Beta particle monitor for surfaces

DOEpatents

MacArthur, Duncan W.

1997-01-01

A beta radiation detector which is capable of reliably detecting beta radiation emitted from a surface. An electrically conductive signal collector is adjustably mounted inside an electrically conductive enclosure which may define a single large opening for placing against a surface. The adjustable mounting of the electrically conductive signal collector can be based on the distance from the surface or on the expected beta energy range. A voltage source is connected to the signal collector through an electrometer or other display means for creating an electric field between the signal collector and the enclosure. Air ions created by the beta radiation are collected and the current produced is indicated on the electrometer or other display means.

Beta particle monitor for surfaces

DOEpatents

MacArthur, D.W.

1997-10-21

A beta radiation detector which is capable of reliably detecting beta radiation emitted from a surface. An electrically conductive signal collector is adjustably mounted inside an electrically conductive enclosure which may define a single large opening for placing against a surface. The adjustable mounting of the electrically conductive signal collector can be based on the distance from the surface or on the expected beta energy range. A voltage source is connected to the signal collector through an electrometer or other display means for creating an electric field between the signal collector and the enclosure. Air ions created by the beta radiation are collected and the current produced is indicated on the electrometer or other display means. 2 figs.

Fab is the most efficient format to express functional antibodies by yeast surface display.

PubMed

Sivelle, Coline; Sierocki, Raphaël; Ferreira-Pinto, Kelly; Simon, Stéphanie; Maillere, Bernard; Nozach, Hervé

2018-04-30

Multiple formats are available for engineering of monoclonal antibodies (mAbs) by yeast surface display, but they do not all lead to efficient expression of functional molecules. We therefore expressed four anti-tumor necrosis factor and two anti-IpaD mAbs as single-chain variable fragment (scFv), antigen-binding fragment (Fab) or single-chain Fabs and compared their expression levels and antigen-binding efficiency. Although the scFv and scFab formats are widely used in the literature, 2 of 6 antibodies were either not or weakly expressed. In contrast, all 6 antibodies expressed as Fab revealed strong binding and high affinity, comparable to that of the soluble form. We also demonstrated that the variations in expression did not affect Fab functionality and were due to variations in light chain display and not to misfolded dimers. Our results suggest that Fab is the most versatile format for the engineering of mAbs.

An efficient method for variable region assembly in the construction of scFv phage display libraries using independent strand amplification

PubMed Central

Sotelo, Pablo H.; Collazo, Noberto; Zuñiga, Roberto; Gutiérrez-González, Matías; Catalán, Diego; Ribeiro, Carolina Hager; Aguillón, Juan Carlos; Molina, María Carmen

2012-01-01

Phage display library technology is a common method to produce human antibodies. In this technique, the immunoglobulin variable regions are displayed in a bacteriophage in a way that each filamentous virus displays the product of a single antibody gene on its surface. From the collection of different phages, it is possible to isolate the virus that recognizes specific targets. The most common form in which to display antibody variable regions in the phage is the single chain variable fragment format (scFv), which requires assembly of the heavy and light immunoglobulin variable regions in a single gene. In this work, we describe a simple and efficient method for the assembly of immunoglobulin heavy and light chain variable regions in a scFv format. This procedure involves a two-step reaction: (1) DNA amplification to produce the single strand form of the heavy or light chain gene required for the fusion; and (2) mixture of both single strand products followed by an assembly reaction to construct a complete scFv gene. Using this method, we produced 6-fold more scFv encoding DNA than the commonly used splicing by overlap extension PCR (SOE-PCR) approach. The scFv gene produced by this method also proved to be efficient in generating a diverse scFv phage display library. From this scFv library, we obtained phages that bound several non-related antigens, including recombinant proteins and rotavirus particles. PMID:22692130

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Fourier analysis of surface plasmon waves launched from single nanohole and nanohole arrays: unraveling tip-induced effects.

PubMed

Chang, Y C; Chu, J Y; Wang, T J; Lin, M W; Yeh, J T; Wang, J K

2008-01-21

The authors report the investigation of surface plasmon waves (SPW) generated by single nanohole and nanohole arrays. Scattering-type scanning near-field microscopy is used to directly observe near-field distribution. The images after Fourier transformation display characteristic patterns that match with the derived analytic formula. The correspondence helps to identify the role of the scanning tip in generating SPW, making possible of the removal of this tip-induced effect. This study provides a means to perform in-depth investigation on surface plasmon polaritons.

Simultaneous display of two large proteins on the head and tail of bacteriophage lambda

PubMed Central

2013-01-01

Background Consistent progress in the development of bacteriophage lambda display platform as an alternative to filamentous phage display system was achieved in the recent years. The lambda phage has been engineered to display efficiently multiple copies of peptides or even large protein domains providing a powerful tool for screening libraries of peptides, proteins and cDNA. Results In the present work we describe an original method for dual display of large proteins on the surface of lambda particles. An anti-CEA single-chain antibody fragment and green fluorescent protein or alkaline phosphatase were simultaneously displayed by engineering both gpD and gpV lambda proteins. Conclusions Here we show that such modified phage particles can be used for the detection of target molecules in vitro and in vivo. Dual expression of functional moieties on the surface of the lambda phage might open the way to generation of a new class of diagnostic and therapeutic targeted nanoparticles. PMID:24073829

Design of a holographic waveguide with L configuration

NASA Astrophysics Data System (ADS)

Xiang, Guangxin-Xin; Li, Wen-Qiang

2016-10-01

In order to decrease the complexity to design and manufacture the turning grating of the configuration with one reflecting surface, an L-shape two-dimension extended configuration with single plate is given in the paper. This configuration consists of one specular reflecting surface and three holographic gratings two in which periods and the groove orientations are totally same, which makes gratings design and fabrication easier. According to the calculation and analysis to the optical path of configuration, the dimension of the turning grating is no larger than 40mm×30mm. The simulation result demonstrates the display configuration is reasonable and correct and can realize the display effect with 30°×30° field of view and Φ30mm large exit pupil. This configuration can be applied to an Augmented Reality Display (AR) or a Head-Mounted Display (HMD).

Secretory expression and surface display of a new and biologically active single-chain insulin (SCI-59) analog by lactic acid bacteria.

PubMed

Mao, Ruifeng; Wu, Dongli; Hu, Shimeng; Zhou, Kangping; Wang, Man; Wang, Yefu

2017-04-01

Insulin plays an important role in drug therapies for diabetes mellitus and as the main route of insulin delivery, subcutaneous injection may cause local discomfort, hypoglycemia, hyperinsulinemia, and patient non-compliance. Therefore, oral delivery of insulin is more preferred. However, there is a low bioavailability due to insulin degradation by proteolytic enzymes and severe pH conditions along the gastrointestinal tract. In order to use the food-grade bacteria lactic acid bacteria (LAB) as oral delivery vehicles, a new and bioactive single-chain insulin (SCI-59) analog, containing the insulin B- and A-chains connected by an eight-residue linker (RSRGLPFR), was secretory expressed in Lactococcus lactis NZ3900 without using an antibiotic resistance gene and displayed onto the surface of various non-viable bacteria (NVBs) without genetic modification. Both the free SCI-59 and SCI-59 displayed on the surface of NVBs are biologically active as assayed by their ability to stimulate Akt signaling in differentiated 3T3-L1 adipocytes. Modification of the pH of the medium by NaOH addition at early time during induction can enhance the bioactivity of SCI-59. The C-terminal fused anchoring domain, three LysM repeats, does not affect the formation of disulfide bonds and/or the folding of SCI-59, and SCI-59 could be exposed properly and fully when SCI-59-3LysM bound to the surface of NVBs. Compared to the free form SCI-59, SCI-59 displayed on the surface of NVBs is more stable in simulate gastric juice. It may open new prospects for possible oral treatments of diabetes using live LAB secreting or NVBs carrying bioactive SCI analogs.

Integrated cockpit display and processor: the best solution for Link-16 applications

NASA Astrophysics Data System (ADS)

Smeyne, Alan L.; Savaya, John

2000-08-01

Link-16 Data Link systems are being added to current avionics systems to provide increased situational awareness and command data. By using a single intelligent display system, the impact to existing aircraft systems to implement Link-16 capabilities is minimized. Litton Guidance & Control Systems (G&CS), a military avionics supplier for more than forty years, provides Open System Architecture (OSA), large screen aircraft display systems. Based on a common set of plug-in modules, these Smart Multi-Function Displays (SMFD) are available in a variety of sizes and processing capabilities, any one of which can meet the Link-16 requirements. Using a single smart SMFD connected to a Link-16 subsystem has many advantages. With digital moving map capability, the SMFD can monitor and display air and ground tracks of both friendly and hostile forces while providing potential threat data to the operator. The SMFD can also monitor vehicle status and mission data to share between friendly air and surface forces. To support the integrated digital battlefield, Link-16 capability is required and the Litton G&CS SMFD provides the processing/display functionality to implement this capability.

Elucidating distinct ion channel populations on the surface of hippocampal neurons via single-particle tracking recurrence analysis

NASA Astrophysics Data System (ADS)

Sikora, Grzegorz; Wyłomańska, Agnieszka; Gajda, Janusz; Solé, Laura; Akin, Elizabeth J.; Tamkun, Michael M.; Krapf, Diego

2017-12-01

Protein and lipid nanodomains are prevalent on the surface of mammalian cells. In particular, it has been recently recognized that ion channels assemble into surface nanoclusters in the soma of cultured neurons. However, the interactions of these molecules with surface nanodomains display a considerable degree of heterogeneity. Here, we investigate this heterogeneity and develop statistical tools based on the recurrence of individual trajectories to identify subpopulations within ion channels in the neuronal surface. We specifically study the dynamics of the K+ channel Kv1.4 and the Na+ channel Nav1.6 on the surface of cultured hippocampal neurons at the single-molecule level. We find that both these molecules are expressed in two different forms with distinct kinetics with regards to surface interactions, emphasizing the complex proteomic landscape of the neuronal surface. Further, the tools presented in this work provide new methods for the analysis of membrane nanodomains, transient confinement, and identification of populations within single-particle trajectories.

Phenotypic Heterogeneity in Attachment of Marine Bacteria toward Antifouling Copolymers Unraveled by AFM.

PubMed

El-Kirat-Chatel, Sofiane; Puymege, Aurore; Duong, The H; Van Overtvelt, Perrine; Bressy, Christine; Belec, Lénaïk; Dufrêne, Yves F; Molmeret, Maëlle

2017-01-01

Up to recent years, bacterial adhesion has mostly been evaluated at the population level. Single cell level has improved in the past few years allowing a better comprehension of the implication of individual behaviors as compared to the one of a whole community. A new approach using atomic force microscopy (AFM) to measure adhesion forces between a live bacterium attached via a silica microbead to the AFM tipless cantilever and the surface has been recently developed. The objectives of this study is to examine the bacterial adhesion to a surface dedicated to ship hulls at the population and the cellular level to understand to what extent these two levels could be correlated. Adhesion of marine bacteria on inert surfaces are poorly studied in particular when substrata are dedicated to ship hulls. Studying these interactions in this context are worthwhile as they may involve different adhesion behaviors, taking place in salty conditions, using different surfaces than the ones usually utilized in the literacy. FRC (fouling release coatings)-SPC (self-polishing coatings) hybrids antifouling coatings have been used as substrata and are of particular interest for designing environmentally friendly surfaces, combining progressive surface erosion and low adhesion properties. In this study, a hybrid coating has been synthetized and used to study the adhesion of three marine bacteria, displaying different surface characteristics, using microplate assays associated with confocal scanning laser microscopy (CSLM) and AFM. This study shows that the bacterial strain that appeared to have the weakest adhesion and biofilm formation abilities when evaluated at the population level using microplates assays and CSLM, displayed stronger adhesion forces on the same surfaces at the single cell level using AFM. In addition, one of the strains tested which presented a strong ability to adhere and to form biofilm at the population level, displayed a heterogeneous phenotypic behavior at the single cell level. Therefore, these results suggest that the evaluation of adhesion at the population level cannot always be correlated with adhesion forces measured individually by AFM and that some bacteria are prone to phenotypic heterogeneity among their population.

SEM technique for displaying the three-dimensional structure of wood

Treesearch

C.W. McMillin

1977-01-01

Samples of green Liriodendron tulipifera L. were bandsawed into l/4-inch cubes and boiled in water for 1 hour. Smooth intersecting radial, tangential, and transverse surfaces were prepared with a handheld, single-edge razor blade. After drying, the cubes were affixed to stubs so that the intersection point of the three sectioned surfaces was...

SEM technique for displaying the three-dimensional structure of wood

Treesearch

Charles W. McMillin

1977-01-01

Samples of green Liriodendron tulipifera L. were bandsawed into 1/4-inch cubes and boiled in water for 1 hour. Smooth intersecting radial, tangential, and transverse surfaces were prepared with a handheld, single-edge razor blade. After drying, the cubes were affixed to stubs so that the intersection point of the three sectioned surfaces was...

Parallel selection of antibody libraries on phage and yeast surfaces via a cross-species display.

PubMed

Patel, Chirag A; Wang, Jinqing; Wang, Xinwei; Dong, Feng; Zhong, Pingyu; Luo, Peter P; Wang, Kevin C

2011-09-01

We created a cross-species display system that allows the display of the same antibody libraries on both prokaryotic phage and eukaryotic yeast without the need for molecular cloning. Using this cross-display system, a large, diverse library can be constructed once and subsequently used for display and selection in both phage and yeast systems. In this article, we performed the parallel phage and yeast selection of an antibody maturation library using this cross-display platform. This parallel selection allowed us to isolate more unique hits than single-species selection, with 162 unique clones from phage and 107 unique clones from yeast. In addition, we were able to shuttle yeast hits back to Escherichia coli cells for affinity characterization at a higher throughput.

Recent advances and product enhancements in reflective cholesteric displays

NASA Astrophysics Data System (ADS)

Khan, Asad; Schneider, Tod; Miller, Nick; Marhefka, Duane; Ernst, Todd; Nicholson, Forrest; Doane, Joseph W.

2005-04-01

Bistable reflective cholesteric displays are a liquid crystal display technology developed to fill a market need for very low power displays on a low-cost, high resolution passive matrix. Their unique look, high reflectivity, bistability, and simple structure make them an ideal flat panel display choice for handheld or other portable devices where small lightweight batteries with long lifetimes are important. We discuss recent advances in cholesteric display technology at Kent Displays such as progress towards single layer black and white displays, standard products, lower cost display modules, and various interface options for cholesteric display applications. It will be shown that inclusion of radio frequency (rf) control options and serial peripheral interface (spi) can greatly enhance the cholesteric display module market penetration by enabling quick integration into end devices. Finally, some discussion will be on the progress of the development of flexible reflective cholesteric displays. These flexible displays can dramatically change industrial design methods by enabling curved surfaces with displays integrated in them. Additional discussion in the paper will include applications of various display modes including signs, hand held instrumentation, and the electronic book and reader.

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kushwaha; Pletikosic, I.; Liang, T.

A long-standing issue in topological insulator research has been to find a bulk single crystal material that provides a high quality platform for characterizing topological surface states without interference from bulk electronic states. This material would ideally be a bulk insulator, have a surface state Dirac point energy well isolated from the bulk valence and conduction bands, display quantum oscillations from the surface state electrons, and be growable as large, high quality bulk single crystals. Here we show that this materials obstacle is overcome by bulk crystals of lightly Sn-doped Bi 1.1Sb 0.9Te 2S grown by the Vertical Bridgeman method.more » We characterize Sn-BSTS via angle-resolved photoemission spectroscopy, scanning tunneling microscopy, transport studies, X-ray diffraction, and Raman scattering. We present this material as a high quality topological insulator that can be reliably grown as bulk single crystals and thus studied by many researchers interested in topological surface states.« less

Phage and Yeast Display.

PubMed

Sheehan, Jared; Marasco, Wayne A

2015-02-01

Despite the availability of antimicrobial drugs, the continued development of microbial resistance--established through escape mutations and the emergence of resistant strains--limits their clinical utility. The discovery of novel, therapeutic, monoclonal antibodies (mAbs) offers viable clinical alternatives in the treatment and prophylaxis of infectious diseases. Human mAb-based therapies are typically nontoxic in patients and demonstrate high specificity for the intended microbial target. This specificity prevents negative impacts on the patient microbiome and avoids driving the resistance of nontarget species. The in vitro selection of human antibody fragment libraries displayed on phage or yeast surfaces represents a group of well-established technologies capable of generating human mAbs. The advantage of these forms of microbial display is the large repertoire of human antibody fragments present during a single selection campaign. Furthermore, the in vitro selection environments of microbial surface display allow for the rapid isolation of antibodies--and their encoding genes--against infectious pathogens and their toxins that are impractical within in vivo systems, such as murine hybridomas. This article focuses on the technologies of phage display and yeast display, as these strategies relate to the discovery of human mAbs for the treatment and vaccine development of infectious diseases.

Engineering the cell surface display of cohesins for assembly of cellulosome-inspired enzyme complexes on Lactococcus lactis

PubMed Central

2010-01-01

Background The assembly and spatial organization of enzymes in naturally occurring multi-protein complexes is of paramount importance for the efficient degradation of complex polymers and biosynthesis of valuable products. The degradation of cellulose into fermentable sugars by Clostridium thermocellum is achieved by means of a multi-protein "cellulosome" complex. Assembled via dockerin-cohesin interactions, the cellulosome is associated with the cell surface during cellulose hydrolysis, forming ternary cellulose-enzyme-microbe complexes for enhanced activity and synergy. The assembly of recombinant cell surface displayed cellulosome-inspired complexes in surrogate microbes is highly desirable. The model organism Lactococcus lactis is of particular interest as it has been metabolically engineered to produce a variety of commodity chemicals including lactic acid and bioactive compounds, and can efficiently secrete an array of recombinant proteins and enzymes of varying sizes. Results Fragments of the scaffoldin protein CipA were functionally displayed on the cell surface of Lactococcus lactis. Scaffolds were engineered to contain a single cohesin module, two cohesin modules, one cohesin and a cellulose-binding module, or only a cellulose-binding module. Cell toxicity from over-expression of the proteins was circumvented by use of the nisA inducible promoter, and incorporation of the C-terminal anchor motif of the streptococcal M6 protein resulted in the successful surface-display of the scaffolds. The facilitated detection of successfully secreted scaffolds was achieved by fusion with the export-specific reporter staphylococcal nuclease (NucA). Scaffolds retained their ability to associate in vivo with an engineered hybrid reporter enzyme, E. coli β-glucuronidase fused to the type 1 dockerin motif of the cellulosomal enzyme CelS. Surface-anchored complexes exhibited dual enzyme activities (nuclease and β-glucuronidase), and were displayed with efficiencies approaching 104 complexes/cell. Conclusions We report the successful display of cellulosome-inspired recombinant complexes on the surface of Lactococcus lactis. Significant differences in display efficiency among constructs were observed and attributed to their structural characteristics including protein conformation and solubility, scaffold size, and the inclusion and exclusion of non-cohesin modules. The surface-display of functional scaffold proteins described here represents a key step in the development of recombinant microorganisms capable of carrying out a variety of metabolic processes including the direct conversion of cellulosic substrates into fuels and chemicals. PMID:20840763

Design and calibration of a vacuum compatible scanning tunneling microscope

NASA Technical Reports Server (NTRS)

Abel, Phillip B.

1990-01-01

A vacuum compatible scanning tunneling microscope was designed and built, capable of imaging solid surfaces with atomic resolution. The single piezoelectric tube design is compact, and makes use of sample mounting stubs standard to a commercially available surface analysis system. Image collection and display is computer controlled, allowing storage of images for further analysis. Calibration results from atomic scale images are presented.

Engineering of an ultra-thin molecular superconductor by charge transfer

DOEpatents

Hla, Saw Wai; Hassanien, Abdelrahim; Kendal, Clark

2016-06-07

A method of forming a superconductive device of a single layer of (BETS).sub.2GaCl.sub.4 molecules on a substrate surface which displays a superconducting gap that increases exponentially with the length of the molecular chain is provided.

Magnetic Memory from Site Isolated Dy(III) on Silica Materials

PubMed Central

2017-01-01

Achieving magnetic remanence at single isolated metal sites dispersed at the surface of a solid matrix has been envisioned as a key step toward information storage and processing in the smallest unit of matter. Here, we show that isolated Dy(III) sites distributed at the surface of silica nanoparticles, prepared with a simple and scalable two-step process, show magnetic remanence and display a hysteresis loop open at liquid 4He temperature, in contrast to the molecular precursor which does not display any magnetic memory. This singular behavior is achieved through the controlled grafting of a tailored Dy(III) siloxide complex on partially dehydroxylated silica nanoparticles followed by thermal annealing. This approach allows control of the density and the structure of isolated, “bare” Dy(III) sites bound to the silica surface. During the process, all organic fragments are removed, leaving the surface as the sole ligand, promoting magnetic remanence. PMID:28386602

Magnetic memory from site isolated Dy(III) on silica materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allouche, Florian; Lapadula, Giuseppe; Siddiqi, Georges

Achieving magnetic remanence at single isolated metal sites dispersed at the surface of a solid matrix has been envisioned as a key step toward information storage and processing in the smallest unit of matter. Here, we show that isolated Dy(III) sites distributed at the surface of silica nanoparticles, prepared with a simple and scalable two-step process, show magnetic remanence and display a hysteresis loop open at liquid 4He temperature, in contrast to the molecular precursor which does not display any magnetic memory. This singular behavior is achieved through the controlled grafting of a tailored Dy(III) siloxide complex on partially dehydroxylatedmore » silica nanoparticles followed by thermal annealing. This approach allows control of the density and the structure of isolated, “bare” Dy(III) sites bound to the silica surface. Throughout the process, all organic fragments are removed, leaving the surface as the sole ligand, promoting magnetic remanence.« less

Magnetic memory from site isolated Dy(III) on silica materials

DOE PAGES

Allouche, Florian; Lapadula, Giuseppe; Siddiqi, Georges; ...

2017-02-22

Achieving magnetic remanence at single isolated metal sites dispersed at the surface of a solid matrix has been envisioned as a key step toward information storage and processing in the smallest unit of matter. Here, we show that isolated Dy(III) sites distributed at the surface of silica nanoparticles, prepared with a simple and scalable two-step process, show magnetic remanence and display a hysteresis loop open at liquid 4He temperature, in contrast to the molecular precursor which does not display any magnetic memory. This singular behavior is achieved through the controlled grafting of a tailored Dy(III) siloxide complex on partially dehydroxylatedmore » silica nanoparticles followed by thermal annealing. This approach allows control of the density and the structure of isolated, “bare” Dy(III) sites bound to the silica surface. Throughout the process, all organic fragments are removed, leaving the surface as the sole ligand, promoting magnetic remanence.« less

Real-time analysis of dual-display phage immobilization and autoantibody screening using quartz crystal microbalance with dissipation monitoring.

PubMed

Rajaram, Kaushik; Losada-Pérez, Patricia; Vermeeren, Veronique; Hosseinkhani, Baharak; Wagner, Patrick; Somers, Veerle; Michiels, Luc

2015-01-01

Over the last three decades, phage display technology has been used for the display of target-specific biomarkers, peptides, antibodies, etc. Phage display-based assays are mostly limited to the phage ELISA, which is notorious for its high background signal and laborious methodology. These problems have been recently overcome by designing a dual-display phage with two different end functionalities, namely, streptavidin (STV)-binding protein at one end and a rheumatoid arthritis-specific autoantigenic target at the other end. Using this dual-display phage, a much higher sensitivity in screening specificities of autoantibodies in complex serum sample has been detected compared to single-display phage system on phage ELISA. Herein, we aimed to develop a novel, rapid, and sensitive dual-display phage to detect autoantibodies presence in serum samples using quartz crystal microbalance with dissipation monitoring as a sensing platform. The vertical functionalization of the phage over the STV-modified surfaces resulted in clear frequency and dissipation shifts revealing a well-defined viscoelastic signature. Screening for autoantibodies using antihuman IgG-modified surfaces and the dual-display phage with STV magnetic bead complexes allowed to isolate the target entities from complex mixtures and to achieve a large response as compared to negative control samples. This novel dual-display strategy can be a potential alternative to the time consuming phage ELISA protocols for the qualitative analysis of serum autoantibodies and can be taken as a departure point to ultimately achieve a point of care diagnostic system.

Enhanced Airport Surface Detection Equipment Applications,

DTIC Science & Technology

1985-04-17

of runway capacity for the single mixed runway case . The ASDE display, however, provides independent position and timing information on runway...restored to within approximately 5 percent of the good visibility capacity for the single mixed runway case . The lack of identity informa- tion on the ASDE...D.C. 20591 ENGINEERING AND ECONOMICS RESEARCH, INC. Technical Support Staff Henry R. Schramm Mignonette E. Stephen A-2 I m i . . . -i , ’ ,.i

Panoramic projection avionics displays

NASA Astrophysics Data System (ADS)

Kalmanash, Michael H.

2003-09-01

Avionics projection displays are entering production in advanced tactical aircraft. Early adopters of this technology in the avionics community used projection displays to replace or upgrade earlier units incorporating direct-view CRT or AMLCD devices. Typical motivation for these upgrades were the alleviation of performance, cost and display device availability concerns. In these systems, the upgraded (projection) displays were one-for-one form / fit replacements for the earlier units. As projection technology has matured, this situation has begun to evolve. The Lockheed-Martin F-35 is the first program in which the cockpit has been specifically designed to take advantage of one of the more unique capabilities of rear projection display technology, namely the ability to replace multiple small screens with a single large conformal viewing surface in the form of a panoramic display. Other programs are expected to follow, since the panoramic formats enable increased mission effectiveness, reduced cost and greater information transfer to the pilot. Some of the advantages and technical challenges associated with panoramic projection displays for avionics applications are described below.

Refreshing Refreshable Braille Displays.

PubMed

Russomanno, Alexander; O'Modhrain, Sile; Gillespie, R Brent; Rodger, Matthew W M

2015-01-01

The increased access to books afforded to blind people via e-publishing has given them long-sought independence for both recreational and educational reading. In most cases, blind readers access materials using speech output. For some content such as highly technical texts, music, and graphics, speech is not an appropriate access modality as it does not promote deep understanding. Therefore blind braille readers often prefer electronic braille displays. But, these are prohibitively expensive. The search is on, therefore, for a low-cost refreshable display that would go beyond current technologies and deliver graphical content as well as text. And many solutions have been proposed, some of which reduce costs by restricting the number of characters that can be displayed, even down to a single braille cell. In this paper, we demonstrate that restricting tactile cues during braille reading leads to poorer performance in a letter recognition task. In particular, we show that lack of sliding contact between the fingertip and the braille reading surface results in more errors and that the number of errors increases as a function of presentation speed. These findings suggest that single cell displays which do not incorporate sliding contact are likely to be less effective for braille reading.

A study of laser surface treatment in bonded repair of composite aircraft structures.

PubMed

Li, Shaolong; Sun, Ting; Liu, Chang; Yang, Wenfeng; Tang, Qingru

2018-03-01

Surface pre-treatment is one of the key processes in bonded repair of aircraft carbon fibre reinforced polymer composites. This paper investigates the surface modification of physical and chemical properties by laser ablation and conventional polish treatment techniques. Surface morphology analysed by laser scanning confocal microscopy and scanning electron microscopy showed that a laser-treated surface displayed higher roughness than that of a polish-treated specimen. The laser-treated laminate exhibited more functional groups in the form of O 1 s/C 1 s atomic ratio of 30.89% for laser-treated and 20.14% for polish-treated as evidenced by X-ray photoelectron spectroscopy observation. Contact angle goniometry demonstrated that laser treatment can provide increased surface free energy and wettability. In the light of mechanical interlocking, molecular bonding and thermodynamics theories on adhesion, laser etching process displayed enhanced bonding performance relative to the polishing surface treatment. These properties resulted in an increased single lap shear strength and a cohesive failure mode for laser etching while an adhesive failure mode occurred in polish-treated specimen.

A study of laser surface treatment in bonded repair of composite aircraft structures

NASA Astrophysics Data System (ADS)

Li, Shaolong; Sun, Ting; Liu, Chang; Yang, Wenfeng; Tang, Qingru

2018-03-01

Surface pre-treatment is one of the key processes in bonded repair of aircraft carbon fibre reinforced polymer composites. This paper investigates the surface modification of physical and chemical properties by laser ablation and conventional polish treatment techniques. Surface morphology analysed by laser scanning confocal microscopy and scanning electron microscopy showed that a laser-treated surface displayed higher roughness than that of a polish-treated specimen. The laser-treated laminate exhibited more functional groups in the form of O 1 s/C 1 s atomic ratio of 30.89% for laser-treated and 20.14% for polish-treated as evidenced by X-ray photoelectron spectroscopy observation. Contact angle goniometry demonstrated that laser treatment can provide increased surface free energy and wettability. In the light of mechanical interlocking, molecular bonding and thermodynamics theories on adhesion, laser etching process displayed enhanced bonding performance relative to the polishing surface treatment. These properties resulted in an increased single lap shear strength and a cohesive failure mode for laser etching while an adhesive failure mode occurred in polish-treated specimen.

A study of laser surface treatment in bonded repair of composite aircraft structures

PubMed Central

Sun, Ting; Liu, Chang; Yang, Wenfeng; Tang, Qingru

2018-01-01

Surface pre-treatment is one of the key processes in bonded repair of aircraft carbon fibre reinforced polymer composites. This paper investigates the surface modification of physical and chemical properties by laser ablation and conventional polish treatment techniques. Surface morphology analysed by laser scanning confocal microscopy and scanning electron microscopy showed that a laser-treated surface displayed higher roughness than that of a polish-treated specimen. The laser-treated laminate exhibited more functional groups in the form of O 1 s/C 1 s atomic ratio of 30.89% for laser-treated and 20.14% for polish-treated as evidenced by X-ray photoelectron spectroscopy observation. Contact angle goniometry demonstrated that laser treatment can provide increased surface free energy and wettability. In the light of mechanical interlocking, molecular bonding and thermodynamics theories on adhesion, laser etching process displayed enhanced bonding performance relative to the polishing surface treatment. These properties resulted in an increased single lap shear strength and a cohesive failure mode for laser etching while an adhesive failure mode occurred in polish-treated specimen. PMID:29657748

Sn-doped Bi 1.1Sb 0.9Te 2S bulk crystal topological insulator with excellent properties

DOE PAGES

S. K. Kushwaha; Pletikosic, I.; Liang, T.; ...

2016-04-27

A long-standing issue in topological insulator research has been to find a bulk single crystal material that provides a high quality platform for characterizing topological surface states without interference from bulk electronic states. This material would ideally be a bulk insulator, have a surface state Dirac point energy well isolated from the bulk valence and conduction bands, display quantum oscillations from the surface state electrons, and be growable as large, high quality bulk single crystals. Here we show that this materials obstacle is overcome by bulk crystals of lightly Sn-doped Bi 1.1Sb 0.9Te 2S grown by the Vertical Bridgeman method.more » We characterize Sn-BSTS via angle-resolved photoemission spectroscopy, scanning tunneling microscopy, transport studies, X-ray diffraction, and Raman scattering. We present this material as a high quality topological insulator that can be reliably grown as bulk single crystals and thus studied by many researchers interested in topological surface states.« less

Phage display of functional αβ single-chain T-cell receptor molecules specific for CD1b:Ac₂SGL complexes from Mycobacterium tuberculosis-infected cells.

PubMed

Camacho, Frank; Huggett, Jim; Kim, Louise; Infante, Juan F; Lepore, Marco; Perez, Viviana; Sarmiento, María E; Rook, Graham; Acosta, Armando

2013-01-01

The development of molecules specific for M. tuberculosis-infected cells has important implications, as these tools may facilitate understanding of the mechanisms regulating host pathogen interactions in vivo. In addition, development of new tools capable to targeting M. tuberculosis-infected cells may have potential applications to diagnosis, treatment, and prevention of tuberculosis (TB). Due to the lack of CD1b polymorphism, M. tuberculosis lipid-CD1b complexes could be considered as universal tuberculosis infection markers. The aim of the present study was to display on the PIII surface protein of m13 phage, a human αβ single-chain T-cell receptor molecule specific for CD1b:2-stearoyl-3-hydroxyphthioceranoyl-2´-sulfate-α-α´-D-trehalose (Ac₂SGL) which is a complex presented by human cells infected with M. tuberculosis. The results showed the pIII fusion particle was successfully displayed on the phage surface. The study of the recognition of the recombinant phage in ELISA and immunohistochemistry showed the recognition of CD1b:Ac₂SGL complexes and cells in human lung tissue from a tuberculosis patient respectively, suggesting the specific recognition of the lipid-CD1b complex.

Ribosome Display of Combinatorial Antibody Libraries Derived from Mice Immunized with Heat-Killed Xylella fastidiosa and the Selection of MopB-Specific Single-Chain Antibodies

PubMed Central

Azizi, Armaghan; Arora, Arinder; Markiv, Anatoliy; Lampe, David J.; Miller, Thomas A.

2012-01-01

Pierce's disease is a devastating lethal disease of Vitus vinifera grapevines caused by the bacterium Xylella fastidiosa. There is no cure for Pierce's disease, and control is achieved predominantly by suppressing transmission of the glassy-winged sharpshooter insect vector. We present a simple robust approach for the generation of panels of recombinant single-chain antibodies against the surface-exposed elements of X. fastidiosa that may have potential use in diagnosis and/or disease transmission blocking studies. In vitro combinatorial antibody ribosome display libraries were assembled from immunoglobulin transcripts rescued from the spleens of mice immunized with heat-killed X. fastidiosa. The libraries were used in a single round of selection against an outer membrane protein, MopB, resulting in the isolation of a panel of recombinant antibodies. The potential use of selected anti-MopB antibodies was demonstrated by the successful application of the 4XfMopB3 antibody in an enzyme-linked immunosorbent assay (ELISA), a Western blot assay, and an immunofluorescence assay (IFA). These immortalized in vitro recombinant single-chain antibody libraries generated against heat-killed X. fastidiosa are a resource for the Pierce's disease research community that may be readily accessed for the isolation of antibodies against a plethora of X. fastidiosa surface-exposed antigenic molecules. PMID:22327580

Highly Stable Nanolattice Structures using Nonlinear Laser Lithography

NASA Astrophysics Data System (ADS)

Yavuz, Ozgun; Tokel, Onur; Ergecen, Emre; Pavlov, Ihor; Makey, Ghaith; Ilday, Fatih Omer

Periodic nanopatterning is crucial for multiple technologies, including photovoltaics and display technologies. Conventional optical lithography techniques require complex masks, while e-beam and ion-beam lithography require expensive equipment. With the Nonlinear Laser Lithography (NLL) technique, we had recently shown that various surfaces can be covered with extremely periodic nanopatterns with ultrafast lasers through a single-step, maskless and inexpensive method. Here, we expand NLL nanopatterns to flexible materials, and also present a fully predictive model for the formation of NLL nanostructures as confirmed with experiments. In NLL, a nonlocal positive feedback mechanism (dipole scattering) competes with a rate limiting negative feedback mechanism. Here, we show that judicious use of the laser polarisation can constrain the lattice symmetry, while the nonlinearities regulate periodicity. We experimentally demonstrate that in addition to one dimensional periodic stripes, two dimensional lattices can be produced on surfaces. In particular, hexagonal and square lattices were produced, which are highly desired for display technologies. Notably, with this approach, we can tile flexible substrates, which can find applications in next generation display technologies.

Effects of multi-directional vibrotactile feedback on vestibular-deficient postural performance during continuous multi-directional support surface perturbations.

PubMed

Sienko, K H; Balkwill, M D; Oddsson, L I E; Wall, C

2008-01-01

Single-axis vibrotactile feedback of trunk tilt provided in real-time has previously been shown to significantly reduce the root-mean-square (RMS) trunk sway in subjects with vestibular loss during single-axis perturbation. This research examines the effect of multi-directional vibrotactile feedback on postural sway during continuous multi-directional surface perturbations when the subjects' eyes are closed. Eight subjects with vestibular loss donned a multi-axis feedback device that mapped body tilt estimates onto their torsos with a 3-row by 16-column array of tactile actuators (tactors). Tactor row indicated tilt magnitude and tactor column indicated tilt direction. Root-mean-square trunk tilt, elliptical fits to trunk sway trajectory areas, percentage of time spent outside a no vibrotactile feedback zone, RMS center of pressure, and anchoring index parameters indicating intersegmental coordination were used to assess the efficacy of the multi-directional vibrotactile balance aid. Four tactor display configurations in addition to the tactors off configuration were evaluated. Subjects had significantly reduced RMS trunk sway, significantly smaller elliptical fits of the trajectory area, and spent significantly less time outside of the no feedback zone in the tactors on versus the tactors off configuration. Among the displays evaluated in this study, there was not an optimal tactor column configuration for standing tasks involving continuous surface perturbations. Furthermore, subjects performed worse when erroneous information was displayed. Therefore, a spatial resolution of 90 degrees (4 columns) seems to be as effective as a spatial resolution of 22.5 degrees (16 columns) for control of standing.

Selection of single chain antibody fragments binding to the extracellular domain of 4-1BB receptor by phage display technology.

PubMed

Bagheri, Salman; Yousefi, Mehdi; Safaie Qamsari, Elmira; Riazi-Rad, Farhad; Abolhassani, Mohsen; Younesi, Vahid; Dorostkar, Ruhollah; Movassaghpour, Ali Akbar; Sharifzadeh, Zahra

2017-03-01

The 4-1BB is a surface glycoprotein that pertains to the tumor necrosis factor-receptor family. There is compelling evidence suggesting important roles for 4-1BB in the immune response, including cell activation and proliferation and also cytokine induction. Because of encouraging results of different agonistic monoclonal antibodies against 4-1BB in the treatment of cancer, infectious, and autoimmune diseases, 4-1BB has been suggested as an attractive target for immunotherapy. In this study, single chain variable fragment phage display libraries, Tomlinson I+J, were screened against specific synthetic oligopeptides (peptides I and II) designed from 4-1BB extracellular domain. Five rounds of panning led to selection of four 4-1BB specific single chain variable fragments (PI.12, PI.42, PII.16, and PII.29) which showed specific reaction to relevant peptides in phage enzyme-linked immunosorbent assay. The selected clones were successfully expressed in Escherichia coli Rosetta-gami 2, and their expression was confirmed by western blot analysis. Enzyme-linked immunosorbent assay experiments indicated that these antibodies were able to specifically recognize 4-1BB without any cross-reactivity with other antigens. Flow cytometry analysis demonstrated an acceptable specific binding of the single chain variable fragments to 4-1BB expressed on CCRF-CEM cells, while no binding was observed with an irrelevant antibody. Anti-4-1BB single chain variable fragments enhanced surface CD69 expression and interleukin-2 production in stimulated CCRF-CEM cells which confirmed the agonistic effect of the selected single chain variable fragments. The data from this study have provided a rationale for further experiments involving the biological functions of anti-4-1BB single chain variable fragments in future studies.

Characterization of directionally solidified lead chloride

NASA Technical Reports Server (NTRS)

Singh, Narsingh Bahadur; Duval, W. M. B.; Rosenthal, B. N.

1988-01-01

A directionally solidified PbCl2 material was prepared and analyzed and subsequently used to grow single crystals. It was found that silicon, halogens, sulfur, magnesium, and phosphorus were the hardest impurities to remove by the single-pass directional freezing. Single crystals grown from the purified material displayed good scattering beam quality and showed no absorption peaks between 0.30 to 20 microns. Direct photographic observations of the solid-liquid interface at several G/V (denoting the temperature gradient and the translation velocity, respectively) ratio values showed that, as the G/V ratio decreased, the interface varied from a smooth convex surface to dendritic.

Development of sugar chain-binding single-chain variable fragment antibody to adult T-cell leukemia cells using glyco-nanotechnology and phage display method.

PubMed

Muchima, Kaname; Todaka, Taro; Shinchi, Hiroyuki; Sato, Ayaka; Tazoe, Arisa; Aramaki, Rikiya; Kakitsubata, Yuhei; Yokoyama, Risa; Arima, Naomichi; Baba, Masanori; Wakao, Masahiro; Ito, Yuji; Suda, Yasuo

2018-04-01

Adult T-cell leukemia (ATL) is an intractable blood cancer caused by the infection of human T-cell leukemia virus type-1, and effective medical treatment is required. It is known that the structure and expression levels of cell surface sugar chains vary depending on cell states such as inflammation and cancer. Thus, it is expected that the antibody specific for ATL cell surface sugar chain would be an effective diagnostic tool and a strong candidate for the development of an anti-ATL drug. Here, we developed a stable sugar chain-binding single-chain variable fragment antibody (scFv) that can bind to ATL cells using a fibre-type Sugar Chip and phage display method. The fiber-type Sugar Chips were prepared using O-glycans released from ATL cell lines. The scFv-displaying phages derived from human B cells (diversity: 1.04 × 108) were then screened using the fiber-type Sugar Chips, and an O-glycan-binding scFv was obtained. The flow cytometry analysis revealed that the scFv predominantly bound to ATL cell lines. The sugar chain-binding properties of the scFv was evaluated by array-type Sugar Chip immobilized with a library of synthetic glycosaminoglycan disaccharide structures. Highly sulphated disaccharide structures were found to have high affinity to scFv.

Synthetic vaccines.

PubMed

Lerner, R A

1983-02-01

Synthetic vaccines are designed with the help of computer-graphics programs. These displays generated by Arthur J. Olson of the Research Institute of Scripps Clinic show a method whereby parts of a viral protein that are on the surface of a virus, and therefore accessible to antibodies, can be identified. The backbone of the surface domain of the protein on the outer shell of the tomato bushy-stunt virus is displayed (1) on the basis of coordinates determined by Stephen C. Harrison of Harvard University and his colleagues. A single peptide of the protein is picked out in yellow, with the side chains of its component amino acids indicated in atomic detail (2). The peptide is enlarged and a sphere representing a water molecule is displayed (3). The sphere is rolled around the peptide to generate a map of the surface accessible to water (4); it does so, following an algorithm developed by Michael L. Connolly, by placing a dot at each point of its closest contact with the peptide, taking account of the sphere's own van der Waals radius (zone of influence, in effect) and that of each atom of the peptide and the rest of the protein. A similar-dot-surface map is generated to show what parts of the peptide are still accessible to water when three copies of the protein are associated in an array on the surface of the virus (5) and when four such arrays (out of 60) are in position on the outer surface of the virus (6).

Single crystalline thin films as a novel class of electrocatalysts

DOE PAGES

Snyder, Joshua; Markovic, Nenad; Stamenkovic, Vojislav

2013-01-01

The ubiquitous use of single crystal metal electrodes has garnered invaluable insight into the relationship between surface atomic structure and functional electrochemical properties. But, the sensitivity of their electrochemical response to surface orientation and the amount of precious metal required can limit their use. We present here a generally applicable procedure for producing thin metal films with a large proportion of atomically flat (111) terraces without the use of an epitaxial template. Thermal annealing in a controlled atmosphere induces long-range ordering of magnetron sputtered thin metal films deposited on an amorphous substrate. The ordering transition in these thin metal filmsmore » yields characteristic (111) electrochemical signatures with minimal amount of material and provides an adequate replacement for oriented bulk single crystals. Our procedure can be generalized towards a novel class of practical multimetallic thin film based electrocatalysts with tunable near-surface compositional profile and morphology. Annealing of atomically corrugated sputtered thin film Pt-alloy catalysts yields an atomically smooth structure with highly crystalline, (111)-like ordered and Pt segregated surface that displays superior functional properties, bridging the gap between extended/bulk surfaces and nanoscale systems.« less

Selection harvests in Amazonian rainforests: long-term impacts on soil properties

Treesearch

K.L. McNabb; M.S. Miller; B.G. Lockaby; B.J. Stokes; R.G. Clawson; John A. Stanturf; J.N.M. Silva

1997-01-01

Surface soil properties were compared among disturbance classes associated with a single-tree selection harvest study installed in 1979 in the Brazilian Amazon. Response variables included pH, total N, total organic C, extractable P, exchangeable K, Ca, Mg, and bulk density. In general, concentrations of all elements displayed residual effects 16 years after harvests...

Multifunctional clickable and protein-repellent magnetic silica nanoparticles

NASA Astrophysics Data System (ADS)

Estupiñán, Diego; Bannwarth, Markus B.; Mylon, Steven E.; Landfester, Katharina; Muñoz-Espí, Rafael; Crespy, Daniel

2016-01-01

Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to biological media due to uncontrolled biomolecule adsorption. Therefore, it is important to develop strategies that reduce non-specific protein-particle interactions without losing the introduced surface functionality. Herein, organosilane chemistry is employed to produce magnetic silica nanoparticles bearing differing amounts of amino and alkene functional groups on their surface as orthogonally addressable chemical functionalities. Simultaneously, a short-chain zwitterion is added to decrease the non-specific adsorption of biomolecules on the nanoparticles surface. The multifunctional particles display reduced protein adsorption after incubation in undiluted fetal bovine serum as well as in single protein solutions (serum albumin and lysozyme). Besides, the particles retain their capacity to selectively react with biomolecules. Thus, they can be covalently bio-functionalized with an antibody by means of orthogonal click reactions. These features make the described multifunctional silica nanoparticles a promising system for the study of surface interactions with biomolecules, targeting, and bio-sensing.Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to biological media due to uncontrolled biomolecule adsorption. Therefore, it is important to develop strategies that reduce non-specific protein-particle interactions without losing the introduced surface functionality. Herein, organosilane chemistry is employed to produce magnetic silica nanoparticles bearing differing amounts of amino and alkene functional groups on their surface as orthogonally addressable chemical functionalities. Simultaneously, a short-chain zwitterion is added to decrease the non-specific adsorption of biomolecules on the nanoparticles surface. The multifunctional particles display reduced protein adsorption after incubation in undiluted fetal bovine serum as well as in single protein solutions (serum albumin and lysozyme). Besides, the particles retain their capacity to selectively react with biomolecules. Thus, they can be covalently bio-functionalized with an antibody by means of orthogonal click reactions. These features make the described multifunctional silica nanoparticles a promising system for the study of surface interactions with biomolecules, targeting, and bio-sensing. Electronic supplementary information (ESI) available: Detailed synthetic procedures and additional experimental light scattering and zeta-potential data. See DOI: 10.1039/c5nr08258g

Synthetic single domain antibodies for the conformational trapping of membrane proteins

PubMed Central

Arnold, Fabian M; Stohler, Peter; Bocquet, Nicolas; Hug, Melanie N; Huber, Sylwia; Siegrist, Martin; Hetemann, Lisa; Gera, Jennifer; Gmür, Samira; Spies, Peter; Gygax, Daniel

2018-01-01

Mechanistic and structural studies of membrane proteins require their stabilization in specific conformations. Single domain antibodies are potent reagents for this purpose, but their generation relies on immunizations, which impedes selections in the presence of ligands typically needed to populate defined conformational states. To overcome this key limitation, we developed an in vitro selection platform based on synthetic single domain antibodies named sybodies. To target the limited hydrophilic surfaces of membrane proteins, we designed three sybody libraries that exhibit different shapes and moderate hydrophobicity of the randomized surface. A robust binder selection cascade combining ribosome and phage display enabled the generation of conformation-selective, high affinity sybodies against an ABC transporter and two previously intractable human SLC transporters, GlyT1 and ENT1. The platform does not require access to animal facilities and builds exclusively on commercially available reagents, thus enabling every lab to rapidly generate binders against challenging membrane proteins. PMID:29792401

Geologic Studies of Planetary Surfaces Using Radar Polarimetric Imaging

NASA Technical Reports Server (NTRS)

Carter, Lynn M.; Campbell, Donald B.; Campbell, Bruce A.

2010-01-01

Radar is a useful remote sensing tool for studying planetary geology because it is sensitive to the composition, structure, and roughness of the surface and can penetrate some materials to reveal buried terrain. The Arecibo Observatory radar system transmits a single sense of circular polarization, and both senses of circular polarization are received, which allows for the construction of the Stokes polarization vector. From the Stokes vector, daughter products such as the circular polarization ratio, the degree of linear polarization, and linear polarization angle are obtained. Recent polarimetric imaging using Arecibo has included Venus and the Moon. These observations can be compared to radar data for terrestrial surfaces to better understand surface physical properties and regional geologic evolution. For example, polarimetric radar studies of volcanic settings on Venus, the Moon and Earth display some similarities, but also illustrate a variety of different emplacement and erosion mechanisms. Polarimetric radar data provides important information about surface properties beyond what can be obtained from single-polarization radar. Future observations using polarimetric synthetic aperture radar will provide information on roughness, composition and stratigraphy that will support a broader interpretation of surface evolution.

A layered Dirac system candidate: Fermi surface and anomalous Berry phase in ZrSiSe

NASA Astrophysics Data System (ADS)

Chiu, Yu-Che; Chen, Kuan-Wen; Graf, David; Zhou, Qiong; Martin, Thomas J.; Chan, Julia Y.; Johannes, Michelle; Baumbach, Ryan E.; Balicas, Luis

ZrSiSe was recently claimed to correspond to a novel type of nodal Dirac system. We synthesized single crystals through a combination of solid state reaction and chemical vapor transport. The as-grown single crystals display residual resistivities on the order of 100 nOhmcm at 2K yielding a resistivity ratio surpassing 200. Magnetoresistance (MR) measurements reveal a non-saturating increase in the resistivity by a factor of 500000% under fields up to 35 Tesla. De Haas van Alphen measurements under high magneticfields reveal a Fermi surface that is more complex than previously reported, although its geometry generally agrees with band structure calculations that indicate Dirac-like dispersion in the bulk around the Fermi energy. The charge carrier effective masses extracted from Lifshitz-Kosevich (LK) fits to the amplitude of quantum oscillations were found to range between 0.08me to 0.5me where me is the free electron mass. Fittings of the oscillatory signal to the LK formalism further reveal the existence of cyclotron orbits displaying non-trivial Berry phases approaching pi, which is consistent with the expectations from band structure calculations. funded by DOE, NSF, NHMFL.

Supramolecular organization of pi-conjugated molecules monitored by single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Alvarez, Laurent; Almadori, Yann; Belhboub, Anouar; Le Parc, Rozenn; Aznar, Raymond; Dieudonné-George, Philippe; Rahmani, Abdelali; Hermet, Patrick; Fossard, Frédéric; Loiseau, Annick; Jousselme, Bruno; Campidelli, Stéphane; Saito, Takeshi; Wang, Guillaume; Bantignies, Jean-Louis

2016-03-01

Photoactive pi-conjugated molecules (quaterthiophene and phthalocyanine) are either encapsulated into the hollow core of single-walled carbon nanotubes or noncovalently stacked at their outer surface in order to elaborate hybrid nanosystems with new physical properties, providing practical routes to fit different requirements for potential applications. We are interested in the relationship between the structure and the optoelectronic properties. The structural properties are investigated mainly by x-ray diffraction and/or transmission electron microscopy and Raman spectroscopy. We show that the supramolecular organizations of confined quaterthiophenes depend on the nanocontainer size, whereas phthalocyanine encapsulation leads to the formation of a one-dimensional phase for which the angle between the molecule ring and the nanotube axis is close to 32 deg. Confined phthalocyanine molecules display Raman spectra hardly altered with respect to the bulk phase, suggesting a rather weak interaction with the tubes. In contrast, the vibrational properties of the molecules stacked at the outer surface of tubes display important modifications. We assume a significant curvature of the phthalocyanine induced by the interaction with the tube walls and a change of the central atom position within the molecular ring, in good agreement with our density functional theory calculations.

Single helically folded aromatic oligoamides that mimic the charge surface of double-stranded B-DNA

NASA Astrophysics Data System (ADS)

Ziach, Krzysztof; Chollet, Céline; Parissi, Vincent; Prabhakaran, Panchami; Marchivie, Mathieu; Corvaglia, Valentina; Bose, Partha Pratim; Laxmi-Reddy, Katta; Godde, Frédéric; Schmitter, Jean-Marie; Chaignepain, Stéphane; Pourquier, Philippe; Huc, Ivan

2018-05-01

Numerous essential biomolecular processes require the recognition of DNA surface features by proteins. Molecules mimicking these features could potentially act as decoys and interfere with pharmacologically or therapeutically relevant protein-DNA interactions. Although naturally occurring DNA-mimicking proteins have been described, synthetic tunable molecules that mimic the charge surface of double-stranded DNA are not known. Here, we report the design, synthesis and structural characterization of aromatic oligoamides that fold into single helical conformations and display a double helical array of negatively charged residues in positions that match the phosphate moieties in B-DNA. These molecules were able to inhibit several enzymes possessing non-sequence-selective DNA-binding properties, including topoisomerase 1 and HIV-1 integrase, presumably through specific foldamer-protein interactions, whereas sequence-selective enzymes were not inhibited. Such modular and synthetically accessible DNA mimics provide a versatile platform to design novel inhibitors of protein-DNA interactions.

Force-Balance Dynamic Display

NASA Technical Reports Server (NTRS)

Ferris, Alice T.; White, William C.

1988-01-01

Balance dynamic display unit (BDDU) is compact system conditioning six dynamic analog signals so they are monitored simultaneously in real time on single-trace oscilloscope. Typical BDDU oscilloscope display in scan mode shows each channel occupying one-sixth of total trace. System features two display modes usable with conventional, single-channel oscilloscope: multiplexed six-channel "bar-graph" format and single-channel display. Two-stage visual and audible limit alarm provided for each channel.

Detailed analysis of complex single molecule FRET data with the software MASH

NASA Astrophysics Data System (ADS)

Hadzic, Mélodie C. A. S.; Kowerko, Danny; Börner, Richard; Zelger-Paulus, Susann; Sigel, Roland K. O.

2016-04-01

The processing and analysis of surface-immobilized single molecule FRET (Förster resonance energy transfer) data follows systematic steps (e.g. single molecule localization, clearance of different sources of noise, selection of the conformational and kinetic model, etc.) that require a solid knowledge in optics, photophysics, signal processing and statistics. The present proceeding aims at standardizing and facilitating procedures for single molecule detection by guiding the reader through an optimization protocol for a particular experimental data set. Relevant features were determined from single molecule movies (SMM) imaging Cy3- and Cy5-labeled Sc.ai5γ group II intron molecules synthetically recreated, to test the performances of four different detection algorithms. Up to 120 different parameterizations per method were routinely evaluated to finally establish an optimum detection procedure. The present protocol is adaptable to any movie displaying surface-immobilized molecules, and can be easily reproduced with our home-written software MASH (multifunctional analysis software for heterogeneous data) and script routines (both available in the download section of www.chem.uzh.ch/rna).

The shape of a hole and that of the surface-with-hole cannot be analyzed separately.

PubMed

Bertamini, Marco; Helmy, Mai Salah

2012-08-01

Figure-ground organization has a central role in visual perception, since it creates the regions to which properties, such as shape descriptions, are then assigned. However, there is disagreement on how much shape analysis is independent of figure-ground. The reversal of figure-ground of a single closed region is the purest form of figure-ground organization, and the two resulting percepts are that of an object and that of a hole. Both object and hole are nonaccidental regions and can share an identical outline. We devised a test of how figure-ground and contour ownership dramatically affect how shape is processed. Observers judged the shape of a contour that could be either the same as or different from an irrelevant surrounding contour. We report that different (incongruent) inside and outside contours produce a stronger interference effect when they form a single object-with-hole, as compared with a hierarchical set of surfaces or a single hole separating different surfaces (a trench). We conclude that (1) which surface owns the contour constrains the interference between shapes and that (2) despite some recent claims, holes do not display objectlike properties.

Expression of full-length HER2 protein in Sf9 insect cells and its presentation on the surface of budded virus-like particles.

PubMed

Nika, Lisa; Wallner, Jakob; Palmberger, Dieter; Koczka, Krisztina; Vorauer-Uhl, Karola; Grabherr, Reingard

2017-08-01

Biomarkers of cancer are often glycosylated membrane receptor proteins present on the cellular surface. In order to develop new antibodies for cancer diagnostics or treatment, it is a main pre-requisite that these target proteins are available in a native conformation. However, membrane receptor proteins are notoriously difficult to produce due to their hydrophobic nature and complex architecture. Here, we used the baculovirus-insect cell expression system to produce budded virus-like particles (VLPs) as the scaffold for the presentation of complex membrane proteins. Since the human epidermal growth factor receptor 2 (HER2) is known to be overexpressed in a number of cancers it was chosen as model for a tumor antigen. VLPs displaying full-length HER2 on the surface were produced in Spodoptera frugiperda 9 (Sf9) insect cells and purified by sucrose gradient ultracentrifugation. The number of secreted particles was quantified by nanoparticle tracking analysis. To confirm the presence of HER2 protein on the surface, VLPs were labeled with gold-conjugated antibodies and analyzed by transmission electron microscopy. Functionality of displayed HER2 was investigated by ELISA and a newly established biolayer interferometry based technique. Detection was accomplished using the specific monoclonal antibody Herceptin and filamentous phages displaying a single-chain variable fragment of an anti-HER2 antibody. Significant stronger binding of Herceptin and anti-HER2 phages to HER2-displaying VLPs as compared to control VLPs was demonstrated. Thus, we suggest that Sf9 insect cells are highly feasible for the fast and easy production of various budded VLPs that serve as a platform for full-length membrane receptor presentation. Copyright © 2017. Published by Elsevier Inc.

Versatile microbial surface-display for environmental remediation and biofuels production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Cindy H.; Mulchandani, Ashok; Chen, wilfred

2008-02-14

Surface display is a powerful technique that utilizes natural microbial functional components to express proteins or peptides on the cell exterior. Since the reporting of the first surface-display system in the mid-1980s, a variety of new systems have been reported for yeast, Gram-positive and Gram-negative bacteria. Non-conventional display methods are emerging, eliminating the generation of genetically modified microorganisms. Cells with surface display are used as biocatalysts, biosorbents and biostimulants. Microbial cell-surface display has proven to be extremely important for numerous applications ranging from combinatorial library screening and protein engineering to bioremediation and biofuels production.

Heterologous surface display on lactic acid bacteria: non-GMO alternative?

PubMed Central

Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

2015-01-01

Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union. PMID:25880164

Heterologous surface display on lactic acid bacteria: non-GMO alternative?

PubMed

Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

2015-01-01

Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union.

Rapid in situ generation of two patterned chemoselective surface chemistries from a single hydroxy-terminated surface using controlled microfluidic oxidation.

PubMed

Pulsipher, Abigail; Westcott, Nathan P; Luo, Wei; Yousaf, Muhammad N

2009-06-10

In this work, we develop a new, rapid and inexpensive method to generate spatially controlled aldehyde and carboxylic acid surface groups by microfluidic oxidation of 11-hydroxyundecylphosphonic acid self-assembled monolayers (SAMs) on indium tin oxide (ITO) surfaces. SAMs are activated and patterned using a reversibly sealable, elastomeric polydimethylsiloxane cassette, fabricated with preformed micropatterns by soft lithography. By flowing the mild oxidant pyridinium chlorochromate through the microchannels, only selected areas of the SAM are chemically altered. This microfluidic oxidation strategy allows for ligand immobilization by two chemistries originating from a single SAM composition. ITO is robust, conductive, and transparent, making it an ideal platform for studying interfacial interactions. We display spatial control over the immobilization of a variety of ligands on ITO and characterize the resulting oxime and amide linkages by electrochemistry, X-ray photoelectron spectroscopy, contact angle, fluorescence microscopy, and atomic force microscopy. This general method may be used with many other materials to rapidly generate patterned and tailored surfaces for studies ranging from molecular electronics to biospecific cell-based assays and biomolecular microarrays.

Identification of Useful Nanobodies by Phage Display of Immune Single Domain Libraries Derived from Camelid Heavy Chain Antibodies.

PubMed

Romao, Ema; Morales-Yanez, Francisco; Hu, Yaozhong; Crauwels, Maxine; De Pauw, Pieter; Hassanzadeh, Gholamreza Ghassanzadeh; Devoogdt, Nick; Ackaert, Chloe; Vincke, Cecile; Muyldermans, Serge

2016-01-01

The discovery of functional heavy chain-only antibodies devoid of light chains in sera of camelids and sharks in the early nineties provided access to the generation of minimal-sized, single-domain, in vivo affinity-matured, recombinant antigenbinding fragments, also known as Nanobodies. Recombinant DNA technology and adaptation of phage display vectors form the basis to construct large naïve, synthetic or medium sized immune libraries from where multiple Nanobodies have been retrieved. Alternative selection methods (i.e. bacterial display, bacterial two-hybrid, Cis-display and ribosome display) have also been developed to identify Nanobodies. The antigen affinity, stability, expression yields and structural details of the Nanobodies have been determined by standard technology. Nanobodies were subsequently engineered for higher stability and affinity, to have a sequence closer to that of human immunoglobulin domains, or to add designed effector functions. Antigen specific Nanobodies recognizing with high affinity their cognate antigen were retrieved from various libraries. High expression yields are obtained from microorganisms, even when expressed in the cytoplasm. The purified Nanobodies are shown to possess beneficial biochemical and biophysical properties. The crystal structure of Nanobody::antigen complexes reveal the preference of Nanobodies for cavities on the antigen surface. Thanks to the properties described above, Nanobodies became a highly valued and versatile tool for biomolecular research. Moreover, numerous diagnostic and therapeutic Nanobody-based applications have been developed in the past decade. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Performance evaluation of phage-displayed synthetic human single-domain antibody libraries: A retrospective analysis.

PubMed

Henry, Kevin A; Tanha, Jamshid

2018-05-01

Fully human synthetic single-domain antibodies (sdAbs) are desirable therapeutic molecules but their development is a considerable challenge. Here, using a retrospective analysis of in-house historical data, we examined the parameters that impact the outcome of screening phage-displayed synthetic human sdAb libraries to discover antigen-specific binders. We found no evidence for a differential effect of domain type (V H or V L ), library randomization strategy, incorporation of a stabilizing disulfide linkage or sdAb display format (monovalent vs. multivalent) on the probability of obtaining any antigen-binding human sdAbs, instead finding that the success of library screens was primarily related to properties of target antigens, especially molecular mass. The solubility and binding affinity of sdAbs isolated from successful screens depended both on properties of the sdAb libraries (primarily domain type) and the target antigens. Taking attrition of sdAbs with major manufacturability concerns (aggregation; low expression) and sdAbs that do not recognize native cell-surface antigens as independent probabilities, we calculate the overall likelihood of obtaining ≥1 antigen-binding human sdAb from a single library-target screen as ~24%. Successful library-target screens should be expected to yield ~1.3 human sdAbs on average, each with average binding affinity of ~2 μM. Copyright © 2018 Elsevier B.V. All rights reserved.

Determining minimal display element requirements for surface map displays

DOT National Transportation Integrated Search

2003-04-14

There is a great deal of interest in developing electronic surface map displays to enhance safety and reduce incidents and incursions on or near the airport surface. There is a lack of research, however, detailing the minimal display elements require...

Recent progress in Bacillus subtilis spore-surface display: concept, progress, and future.

PubMed

Wang, He; Wang, Yunxiang; Yang, Ruijin

2017-02-01

With the increased knowledge on spore structure and advances in biotechnology engineering, the newly developed spore-surface display system confers several inherent advantages over other microbial cell-surface display systems including enhanced stability and high safety. Bacillus subtilis is the most commonly used Bacillus species for spore-surface display. The expression of heterologous antigen or protein on the surface of B. subtilis spores has now been practiced for over a decade with noteworthy success. As an update and supplement to other previous reviews, we comprehensively summarize recent studies in the B. subtilis spore-surface display technique. We focus on its benefits as well as the critical factors affecting its display efficiency and offer suggestions for the future success of this field.

Virtual surface characteristics of a tactile display using magneto-rheological fluids.

PubMed

Lee, Chul-Hee; Jang, Min-Gyu

2011-01-01

Virtual surface characteristics of tactile displays are investigated to characterize the feeling of human touch for a haptic interface application. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, friction, and topography of the surface. Thus, the tactile display can provide information on the surface of an organic tissue to the surgeon in virtual reality. In order to investigate the compliance feeling of a human finger's touch, normal force responses of a tactile display under various magnetic fields have been assessed. Also, shearing friction force responses of the tactile display are investigated to simulate the action of finger dragging on the surface. Moreover, different matrix arrays of magnetic poles are applied to form the virtual surface topography. From the results, different tactile feelings are observed according to the applied magnetic field strength as well as the arrays of magnetic poles combinations. This research presents a smart tactile display technology for virtual surfaces.

Individual Magnetic Molecules on Ultrathin Insulating Surfaces

NASA Astrophysics Data System (ADS)

El Hallak, Fadi; Warner, Ben; Hirjibehedin, Cyrus

2012-02-01

Single molecule magnets have attracted ample interest because of their exciting magnetic and quantum properties. Recent studies have demonstrated that some of these molecules can be evaporated on surfaces without losing their magnetic properties [M. Mannini et al., Nature 468, 417, (2010)]. This remarkable progress enhances the chances of real world applications for these molecules. We present STM imaging and spectroscopy data on iron phthalocyanine molecules deposited on Cu(100) and on a Cu2N ultrathin insulating surface. These molecules have been shown to display a large magnetic anisotropy on another thin insulating surface, oxidized Cu(110) [N. Tsukahara et al., Phys. Rev. Lett. 102, 167203 (2009)]. By using a combination of elastic and inelastic electron tunnelling spectroscopy, we investigate the binding of the molecules to the surface and the impact that the surface has on their electronic and magnetic properties.

Yeast surface display of dehydrogenases in microbial fuel-cells.

PubMed

Gal, Idan; Schlesinger, Orr; Amir, Liron; Alfonta, Lital

2016-12-01

Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3μWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9μWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Generation of a Highly Reactive Chicken-Derived Single-Chain Variable Fragment against Fusarium verticillioides by Phage Display

PubMed Central

Hu, Zu-Quan; Liu, Jin-Long; Li, He-Ping; Xing, Shu; Xue, Sheng; Zhang, Jing-Bo; Wang, Jian-Hua; Nölke, Greta; Liao, Yu-Cai

2012-01-01

Fusarium verticillioides is the primary causal agent of Fusarium ear and kernel rot in maize, producing fumonisin mycotoxins that are toxic to humans and domestic animals. Rapid detection and monitoring of fumonisin-producing fungi are pivotally important for the prevention of mycotoxins from entering into food/feed products. Chicken-derived single-chain variable fragments (scFvs) against cell wall-bound proteins from F. verticillioides were isolated from an immunocompetent phage display library. Comparative phage enzyme-linked immunosorbant assays (ELISAs) and sequencing analyses identified four different scFv antibodies with high sensitivity. Soluble antibody ELISAs identified two highly sensitive scFv antibodies, FvCA3 and FvCA4, with the latter being slightly more sensitive. Three-dimensional modeling revealed that the FvCA4 may hold a better overall structure with CDRH3, CDRL1 and CDRL3 centered in the core region of antibody surface compared with that of other scFvs. Immunofluorescence labeling revealed that the binding of FvCA4 antibody was localized to the cell walls of conidiospores and hyphae of F. verticillioides, confirming the specificity of this antibody for a surface target. This scFv antibody was able to detect the fungal mycelium as low as 10−2 μg/mL and contaminating mycelium at a quantity of 10−2 mg/g maize. This is the first report that scFv antibodies derived from phage display have a wide application for rapid and accurate detection and monitoring of fumonisin-producing pathogens in agricultural samples. PMID:22837678

Identification of malaria parasite-infected red blood cell surface aptamers by inertial microfluidic SELEX (I-SELEX)

NASA Astrophysics Data System (ADS)

Birch, Christina M.; Hou, Han Wei; Han, Jongyoon; Niles, Jacquin C.

2015-07-01

Plasmodium falciparum malaria parasites invade and remodel human red blood cells (RBCs) by trafficking parasite-synthesized proteins to the RBC surface. While these proteins mediate interactions with host cells that contribute to disease pathogenesis, the infected RBC surface proteome remains poorly characterized. Here we use a novel strategy (I-SELEX) to discover high affinity aptamers that selectively recognize distinct epitopes uniquely present on parasite-infected RBCs. Based on inertial focusing in spiral microfluidic channels, I-SELEX enables stringent partitioning of cells (efficiency ≥ 106) from unbound oligonucleotides at high volume throughput (~2 × 106 cells min-1). Using an RBC model displaying a single, non-native antigen and live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct, surface-displayed epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, var2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.

Autotransporter-based cell surface display in Gram-negative bacteria.

PubMed

Nicolay, Toon; Vanderleyden, Jos; Spaepen, Stijn

2015-02-01

Cell surface display of proteins can be used for several biotechnological applications such as the screening of protein libraries, whole cell biocatalysis and live vaccine development. Amongst all secretion systems and surface appendages of Gram-negative bacteria, the autotransporter secretion pathway holds great potential for surface display because of its modular structure and apparent simplicity. Autotransporters are polypeptides made up of an N-terminal signal peptide, a secreted or surface-displayed passenger domain and a membrane-anchored C-terminal translocation unit. Genetic replacement of the passenger domain allows for the surface display of heterologous passengers. An autotransporter-based surface expression module essentially consists of an application-dependent promoter system, a signal peptide, a passenger domain of interest and the autotransporter translocation unit. The passenger domain needs to be compatible with surface translocation although till now no general rules have been determined to test this compatibility. The autotransporter technology for surface display of heterologous passenger domains is critically discussed for various applications.

Wetting Hysteresis at the Molecular Scale

NASA Technical Reports Server (NTRS)

Jin, Wei; Koplik, Joel; Banavar, Jayanth R.

1996-01-01

The motion of a fluid-fluid-solid contact line on a rough surface is well known to display hysteresis in the contact angle vs. velocity relationship. In order to understand the phenomenon at a fundamental microscopic level, we have conducted molecular dynamics computer simulations of a Wilhelmy plate experiment in which a solid surface is dipped into a liquid bath, and the force-velocity characteristics are measured. We directly observe a systematic variation of force and contact angle with velocity, which is single-valued for the case of an atomically smooth solid surface. In the microscopically rough case, however, we find (as intuitively expected) an open hysteresis loop. Further characterization of the interface dynamics is in progress.

Thermocapillary Convection in Liquid Droplets

NASA Technical Reports Server (NTRS)

1986-01-01

The purpose of this video is to understand the effects of surface tension on fluid convection. The fluid system chosen is the liquid sessile droplet to show the importance in single crystal growth, the spray drying and cooling of metal, and the advance droplet radiators of the space stations radiators. A cross sectional representation of a hemispherical liquid droplet under ideal conditions is used to show internal fluid motion. A direct simulation of buoyancy-dominant convection and surface tension-dominant convection is graphically displayed. The clear differences between two mechanisms of fluid transport, thermocapillary convection, and bouncy dominant convection is illustrated.

Dissociation of methane on the surface of charged defective carbon nanotubes

NASA Astrophysics Data System (ADS)

Guo, Z. H.; Yan, X. H.; Xiao, Y.

2010-03-01

Based on the framework of density functional theory (CASTEP and DMOL 3 codes), we simulate the dissociation of methane (CH 4) molecule on the surface of charged defective carbon nanotubes (CNTs). The results display that a charged CNT with carbon (C) and molybdenum (Mo) dopants can effectively dissociate CH 4 molecule, and the adsorption strength of H and CH 3 can be controlled by the injected negative charges. Moreover, the barrier between the transition state (TS) and the reactant is 0.1014 eV, and a single imaginary frequency of -0.3 cm is found for the transition state structure.

Stabilizing subnanometer Ag(0) nanoclusters by thiolate and diphosphine ligands and their crystal structures

NASA Astrophysics Data System (ADS)

Yang, Huayan; Wang, Yu; Zheng, Nanfeng

2013-03-01

The combined use of thiolate and diphosphine as surface ligands helps to stabilize subnanometer Ag(0) nanoclusters, resulting in the successful crystallization of two Ag(0)-containing nanoclusters (Ag16 and Ag32) for X-ray single crystal analysis. Both clusters have core-shell structures with Ag86+ and Ag2212+ as their cores, which are not simply either fragments of face-centered cubic metals or their five-fold twinned counterparts. The clusters display UV-Vis absorption spectra consisting of molecule-like optical transitions.The combined use of thiolate and diphosphine as surface ligands helps to stabilize subnanometer Ag(0) nanoclusters, resulting in the successful crystallization of two Ag(0)-containing nanoclusters (Ag16 and Ag32) for X-ray single crystal analysis. Both clusters have core-shell structures with Ag86+ and Ag2212+ as their cores, which are not simply either fragments of face-centered cubic metals or their five-fold twinned counterparts. The clusters display UV-Vis absorption spectra consisting of molecule-like optical transitions. Electronic supplementary information (ESI) available: Experimental details, more pictures of the structure and XPS spectra of the clusters. CCDC 916463 and 916464. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3nr34328f

Cell-surface display of enzymes by the yeast Saccharomyces cerevisiae for synthetic biology.

PubMed

Tanaka, Tsutomu; Kondo, Akihiko

2015-02-01

In yeast cell-surface displays, functional proteins, such as cellulases, are genetically fused to an anchor protein and expressed on the cell surface. Saccharomyces cerevisiae, which is often utilized as a cell factory for the production of fuels, chemicals, and proteins, is the most commonly used yeast for cell-surface display. To construct yeast cells with a desired function, such as the ability to utilize cellulose as a substrate for bioethanol production, cell-surface display techniques for the efficient expression of enzymes on the cell membrane need to be combined with metabolic engineering approaches for manipulating target pathways within cells. In this Minireview, we summarize the recent progress of biorefinery fields in the development and application of yeast cell-surface displays from a synthetic biology perspective and discuss approaches for further enhancing cell-surface display efficiency. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Multiple-Flat-Panel System Displays Multidimensional Data

NASA Technical Reports Server (NTRS)

Gundo, Daniel; Levit, Creon; Henze, Christopher; Sandstrom, Timothy; Ellsworth, David; Green, Bryan; Joly, Arthur

2006-01-01

The NASA Ames hyperwall is a display system designed to facilitate the visualization of sets of multivariate and multidimensional data like those generated in complex engineering and scientific computations. The hyperwall includes a 77 matrix of computer-driven flat-panel video display units, each presenting an image of 1,280 1,024 pixels. The term hyperwall reflects the fact that this system is a more capable successor to prior computer-driven multiple-flat-panel display systems known by names that include the generic term powerwall and the trade names PowerWall and Powerwall. Each of the 49 flat-panel displays is driven by a rack-mounted, dual-central-processing- unit, workstation-class personal computer equipped with a hig-hperformance graphical-display circuit card and with a hard-disk drive having a storage capacity of 100 GB. Each such computer is a slave node in a master/ slave computing/data-communication system (see Figure 1). The computer that acts as the master node is similar to the slave-node computers, except that it runs the master portion of the system software and is equipped with a keyboard and mouse for control by a human operator. The system utilizes commercially available master/slave software along with custom software that enables the human controller to interact simultaneously with any number of selected slave nodes. In a powerwall, a single rendering task is spread across multiple processors and then the multiple outputs are tiled into one seamless super-display. It must be noted that the hyperwall concept subsumes the powerwall concept in that a single scene could be rendered as a mosaic image on the hyperwall. However, the hyperwall offers a wider set of capabilities to serve a different purpose: The hyperwall concept is one of (1) simultaneously displaying multiple different but related images, and (2) providing means for composing and controlling such sets of images. In place of elaborate software or hardware crossbar switches, the hyperwall concept substitutes reliance on the human visual system for integration, synthesis, and discrimination of patterns in complex and high-dimensional data spaces represented by the multiple displayed images. The variety of multidimensional data sets that can be displayed on the hyperwall is practically unlimited. For example, Figure 2 shows a hyperwall display of surface pressures and streamlines from a computational simulation of airflow about an aerospacecraft at various Mach numbers and angles of attack. In this display, Mach numbers increase from left to right and angles of attack increase from bottom to top. That is, all images in the same column represent simulations at the same Mach number, while all images in the same row represent simulations at the same angle of attack. The same viewing transformations and the same mapping from surface pressure to colors were used in generating all the images.

Method for Visually Integrating Multiple Data Acquisition Technologies for Real Time and Retrospective Analysis

NASA Technical Reports Server (NTRS)

Bogart, Edward H. (Inventor); Pope, Alan T. (Inventor)

2000-01-01

A system for display on a single video display terminal of multiple physiological measurements is provided. A subject is monitored by a plurality of instruments which feed data to a computer programmed to receive data, calculate data products such as index of engagement and heart rate, and display the data in a graphical format simultaneously on a single video display terminal. In addition live video representing the view of the subject and the experimental setup may also be integrated into the single data display. The display may be recorded on a standard video tape recorder for retrospective analysis.

Temperature dependence of magnetoresistance in copper single crystals

NASA Astrophysics Data System (ADS)

Bian, Q.; Niewczas, M.

2018-03-01

Transverse magnetoresistance of copper single crystals has been measured in the orientation of open-orbit from 2 K to 20 K for fields up to 9 T. The experimental Kohler's plots display deviation between individual curves below 16 K and overlap in the range of 16 K-20 K. The violation of the Kohler's rule below 16 K indicates that the magnetotransport can not be described by the classical theory of electron transport on spherical Fermi surface with a single relaxation time. A theoretical model incorporating two energy bands, spherical and cylindrical, with different relaxation times has been developed to describe the magnetoresistance data. The calculations show that the electron-phonon scattering rates at belly and neck regions of the Fermi surface have different temperature dependencies, and in general, they do not follow T3 law. The ratio of the relaxation times in belly and neck regions decreases parabolically with temperature as A - CT2 , with A and C being constants.

Display of adenoregulin with a novel Pichia pastoris cell surface display system.

PubMed

Ren, Ren; Jiang, Zhengbing; Liu, Meiyun; Tao, Xinyi; Ma, Yushu; Wei, Dongzhi

2007-02-01

Two Pichia pastoris cell surface display vectors were constructed. The vectors consisted of the flocculation functional domain of Flo1p with its own secretion signal sequence or the alpha-factor secretion signal sequence, a polyhistidine (6xHis) tag for detection, an enterokinase recognition site, and the insertion sites for target proteins. Adenoregulin (ADR) is a 33-amino-acid antimicrobial peptide isolated from Phyllomedusa bicolor skin. The ADR was expressed and displayed on the Pichia pastoris KM71 cell surface with the system reported. The displayed recombinant ADR fusion protein was detected by fluorescence microscopy and confocal laser scanning microscopy (CLSM). The antimicrobial activity of the recombinant adenoregulin was detected after proteolytic cleavage of the fusion protein on cell surface. The validity of the Pichia pastoris cell surface display vectors was proved by the displayed ADR.

Ethanol oxidation on Pt single-crystal electrodes: surface-structure effects in alkaline medium.

PubMed

Busó-Rogero, Carlos; Herrero, Enrique; Feliu, Juan M

2014-07-21

Ethanol oxidation in 0.1 M NaOH on single-crystal electrodes has been studied using electrochemical and FTIR techniques. The results show that the activity order is the opposite of that found in acidic solutions. The Pt(111) electrode displays the highest currents and also the highest onset potential of all the electrodes. The onset potential for the oxidation of ethanol is linked to the adsorption of OH on the electrode surface. However, small (or even negligible) amounts of CO(ads) and carbonate are detected by FTIR, which implies that cleavage of the C-C bond is not favored in this medium. The activity of the electrodes diminishes quickly upon cycling. The diminution of the activity is proportional to the measured currents and is linked to the formation and polymerization of acetaldehyde, which adsorbs onto the electrode surface and prevents further oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the limited recognition of inorganic surfaces by short peptides compared with antibodies.

PubMed

Artzy-Schnirman, Arbel; Abu-Shah, Enas; Dishon, Matan; Soifer, Hadas; Sivan, Yotam; Reiter, Yoram; Benhar, Itai; Sivan, Uri

2014-06-01

The vast potential applications of biomolecules that bind inorganic surfaces led mostly to the isolation of short peptides that target selectively specific materials. The demonstrated differential affinity toward certain surfaces created the impression that the recognition capacity of short peptides may match that of rigid biomolecules. In the following, we challenge this view by comparing the capacity of antibody molecules to discriminate between the (100) and (111A) facets of a gallium arsenide semiconductor crystal with the capacity of short peptides to do the same. Applying selection from several peptide and single chain phage display libraries, we find a number of antibody molecules that bind preferentially a given crystal facet but fail to isolate, in dozens of attempts, a single peptide capable of such recognition. The experiments underscore the importance of rigidity to the recognition of inorganic flat targets and therefore set limitations on potential applications of short peptides in biomimetics. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

The computation of all plane/surface intersections for CAD/CAM applications

NASA Technical Reports Server (NTRS)

Hoitsma, D. H., Jr.; Roche, M.

1984-01-01

The problem of the computation and display of all intersections of a given plane with a rational bicubic surface patch for use on an interactive CAD/CAM system is examined. The general problem of calculating all intersections of a plane and a surface consisting of rational bicubic patches is reduced to the case of a single generic patch by applying a rejection algorithm which excludes all patches that do not intersect the plane. For each pertinent patch the algorithm presented computed the intersection curves by locating an initial point on each curve, and computes successive points on the curve using a tolerance step equation. A single cubic equation solver is used to compute the initial curve points lying on the boundary of a surface patch, and the method of resultants as applied to curve theory is used to determine critical points which, in turn, are used to locate initial points that lie on intersection curves which are in the interior of the patch. Examples are given to illustrate the ability of this algorithm to produce all intersection curves.

Effect of annealing ambience on the formation of surface/bulk oxygen vacancies in TiO2 for photocatalytic hydrogen evolution

NASA Astrophysics Data System (ADS)

Hou, Lili; Zhang, Min; Guan, Zhongjie; Li, Qiuye; Yang, Jianjun

2018-01-01

The surface and bulk oxygen vacancy have a prominent effect on the photocatalytic performance of TiO2. In this study, TiO2 possessing different types and concentration of oxygen vacancies were prepared by annealing nanotube titanic acid (NTA) at various temperatures in air or vacuum atmosphere. TiO2 with the unitary bulk single-electron-trapped oxygen vacancies (SETOVs) formed when NTA were calcined in air. Whereas, TiO2 with both bulk and surface oxygen vacancies were obtained when NTA were annealed in vacuum. The series of TiO2 with different oxygen vacancies were systematically characterized by TEM, XRD, PL, XPS, ESR, and TGA. The PL and ESR analysis verified that surface oxygen vacancies and more bulk oxygen vacancies could form in vacuum atmosphere. Surface oxygen vacancies can trap electron and hinder the recombination of photo-generated charges, while bulk SETOVs act as the recombination center. The surface or bulk oxygen vacancies attributed different roles on the photo-absorbance and activity, leading that the sample of NTA-A400 displayed higher hydrogen evolution rate under UV light, whereas NTA-V400 displayed higher hydrogen evolution rate under visible light because bulk SETOVs can improve visible light absorption because sub-band formed by bulk SETOVs prompted the secondary transition of electron excited.

T Cell Receptor Engineering and Analysis Using the Yeast Display Platform

PubMed Central

Smith, Sheena N.; Harris, Daniel T.; Kranz, David M.

2017-01-01

The αβ heterodimeric T cell receptor (TCR) recognizes peptide antigens that are transported to the cell surface as a complex with a protein encoded by the major histocompatibility complex (MHC). T cells thus evolved a strategy to sense these intracellular antigens, and to respond either by eliminating the antigen-presenting cell (e.g. a virus-infected cell) or by secreting factors that recruit the immune system to the site of the antigen. The central role of the TCR in the binding of antigens as peptide-MHC (pepMHC) ligands has now been studied thoroughly. Interestingly, despite their exquisite sensitivity (e.g. T cell activation by as few as 1 to 3 pepMHC complexes on a single target cell), TCRs are known to have relatively low affinities for pepMHC, with KD values in the micromolar range. There has been interest in engineering the affinity of TCRs in order to use this class of molecules in ways similar to now done with antibodies. By doing so, it would be possible to harness the potential of TCRs as therapeutics against a much wider array of antigens that include essentially all intracellular targets. To engineer TCRs, and to analyze their binding features more rapidly, we have used a yeast display system as a platform. Expression and engineering of a single-chain form of the TCR, analogous to scFv fragments from antibodies, allow the TCR to be affinity matured with a variety of possible pepMHC ligands. In addition, the yeast display platform allows one to rapidly generate TCR variants with diverse binding affinities and to analyze specificity and affinity without the need for purification of soluble forms of the TCRs. The present chapter describes the methods for engineering and analyzing single-chain TCRs using yeast display. PMID:26060072

DOE Office of Scientific and Technical Information (OSTI.GOV)

Díaz-Torres, Raúl; Menelaou, Melita; Roubeau, Olivier

This work introduces a novel family of Co II species having a curcuminoid (CCMoid) ligand, 9Accm, attached, namely [Co(9Accm) 2 (py) 2 ] (1) and [Co(9Accm) 2(2,2'-bpy)] (2), achieved in high yields by the use of a microwave reactor, and exhibiting two different arrangements for the 9Accm ligands, described as "cis"(2) and "trans"(1). The study of the similarities/differences of the magnetic, luminescent and surface behaviors of the two new species, 1 and 2, is the main objective of the present work. The determined single-crystal structures of both compounds are the only Co II -CCMoid structures described in the literature somore » far. Both compounds exhibit large positive D values, that of 1 (D = +74 cm -1 ) being three times larger than that of 2 (D = +24 cm -1 ), and behave as mononuclear Single-Molecule Magnets (SMMs) in the presence of an external magnetic field. Their similar structures but different anisotropy and SMM characteristics provide, for the first time, deep insight on the spin-orbital effects thanks to the use of CASSCF/NEVPT2 calculations implementing such contributions. Further magnetic studies were performed in solution by means of paramagnetic 1H NMR, where both compounds (1 and 2) are stable in CDCl 3 and display high symmetry. Paramagnetic NMR appears to be a useful diagnostic tool for the identification of such molecules in solution, where the resonance values found for the methine group (-CH-) of 9Accm vary significantly depending on the cis or trans disposition of the ligands. Fluorescence studies show that both systems display chelation enhancement of quenching (CHEQ) with regard to the free ligand, while 1 and 2 display similar quantum yields. Deposition of 1-2 on HOPG and Si(100) surfaces using spin-coating was studied using AFM; UV photoemission experiments under the same conditions display 2 as the most robust system. The measured occupied density of states of 2 with UV photoemission is in excellent agreement with theoretical DFT calculations.« less

Multifunctional clickable and protein-repellent magnetic silica nanoparticles.

PubMed

Estupiñán, Diego; Bannwarth, Markus B; Mylon, Steven E; Landfester, Katharina; Muñoz-Espí, Rafael; Crespy, Daniel

2016-02-07

Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to biological media due to uncontrolled biomolecule adsorption. Therefore, it is important to develop strategies that reduce non-specific protein-particle interactions without losing the introduced surface functionality. Herein, organosilane chemistry is employed to produce magnetic silica nanoparticles bearing differing amounts of amino and alkene functional groups on their surface as orthogonally addressable chemical functionalities. Simultaneously, a short-chain zwitterion is added to decrease the non-specific adsorption of biomolecules on the nanoparticles surface. The multifunctional particles display reduced protein adsorption after incubation in undiluted fetal bovine serum as well as in single protein solutions (serum albumin and lysozyme). Besides, the particles retain their capacity to selectively react with biomolecules. Thus, they can be covalently bio-functionalized with an antibody by means of orthogonal click reactions. These features make the described multifunctional silica nanoparticles a promising system for the study of surface interactions with biomolecules, targeting, and bio-sensing.

Touchscreen everywhere: on transferring a normal planar surface to a touch-sensitive display.

PubMed

Dai, Jingwen; Chung, Chi-Kit Ronald

2014-08-01

We address how a human-computer interface with small device size, large display, and touch-input facility can be made possible by a mere projector and camera. The realization is through the use of a properly embedded structured light sensing scheme that enables a regular light-colored table surface to serve the dual roles of both a projection screen and a touch-sensitive display surface. A random binary pattern is employed to code structured light in pixel accuracy, which is embedded into the regular projection display in a way that the user perceives only regular display but not the structured pattern hidden in the display. With the projection display on the table surface being imaged by a camera, the observed image data, plus the known projection content, can work together to probe the 3-D workspace immediately above the table surface, like deciding if there is a finger present and if the finger touches the table surface, and if so, at what position on the table surface the contact is made. All the decisions hinge upon a careful calibration of the projector-camera-table surface system, intelligent segmentation of the hand in the image data, and exploitation of the homography mapping existing between the projector's display panel and the camera's image plane. Extensive experimentation including evaluation of the display quality, hand segmentation accuracy, touch detection accuracy, trajectory tracking accuracy, multitouch capability and system efficiency are shown to illustrate the feasibility of the proposed realization.

Density Functional Theory Study of Chemical Sensing on Surfaces of Single-Layer MOS2 and Graphene (Postprint)

DTIC Science & Technology

2014-04-22

Ruth Pachter AFRL/RXA APRIL 2014 Interim Report Distribution A . Approved for public release; distribution unlimited. See...subject to any penalty for failing to comply with a collection of information if it dows not display a currently valid OMB control number. PLEASE DO NOT...SPONSOR/MONITOR’S REPORT NUMBER(S) AFRL-RX-WP-JA-2014-0158 12. DISTRIBUTION / AVAILABILITY STATEMENT Distribution A . Approved for public release

Green fluorescent protein nanopolygons as monodisperse supramolecular assemblies of functional proteins with defined valency

PubMed Central

Kim, Young Eun; Kim, Yu-na; Kim, Jung A.; Kim, Ho Min; Jung, Yongwon

2015-01-01

Supramolecular protein assemblies offer novel nanoscale architectures with molecular precision and unparalleled functional diversity. A key challenge, however, is to create precise nano-assemblies of functional proteins with both defined structures and a controlled number of protein-building blocks. Here we report a series of supramolecular green fluorescent protein oligomers that are assembled in precise polygonal geometries and prepared in a monodisperse population. Green fluorescent protein is engineered to be self-assembled in cells into oligomeric assemblies that are natively separated in a single-protein resolution by surface charge manipulation, affording monodisperse protein (nano)polygons from dimer to decamer. Several functional proteins are multivalently displayed on the oligomers with controlled orientations. Spatial arrangements of protein oligomers and displayed functional proteins are directly visualized by a transmission electron microscope. By employing our functional protein assemblies, we provide experimental insight into multivalent protein–protein interactions and tools to manipulate receptor clustering on live cell surfaces. PMID:25972078

Multilevel organization in hybrid thin films for optoelectronic applications.

PubMed

Vohra, Varun; Bolognesi, Alberto; Calzaferri, Gion; Botta, Chiara

2009-10-20

In this work we report two simple approaches to prepare hybrid thin films displaying a high concentration of zeolite crystals that could be used as active layers in optoelectronic devices. In the first approach, in order to organize nanodimensional zeolite crystals of 40 nm diameter in an electroactive environment, we chemically modify their external surface and play on the hydrophilic/hydrophobic forces. We obtain inorganic nanocrystals that self-organize in honeycomb electroluminescent polymer structures obtained by breath figure formation. The different functionalizations of the zeolite surface result in different organizations inside the cavities of the polymeric structure. The second approach involving soft-litography techniques allows one to arrange single dye-loaded zeolite L crystals of 800 nm of length by mechanical loading into the nanocavities of a conjugated polymer. Both techniques result in the formation of thin hybrid films displaying three levels of organization: organization of the dye molecules inside the zeolite nanochannels, organization of the zeolite crystals inside the polymer cavities, and micro- or nanostructuration of the polymer.

Networks of gold nanoparticles and bacteriophage as biological sensors and cell-targeting agents

PubMed Central

Souza, Glauco R.; Christianson, Dawn R.; Staquicini, Fernanda I.; Ozawa, Michael G.; Snyder, Evan Y.; Sidman, Richard L.; Miller, J. Houston; Arap, Wadih; Pasqualini, Renata

2006-01-01

Biological molecular assemblies are excellent models for the development of nanoengineered systems with desirable biomedical properties. Here we report an approach for fabrication of spontaneous, biologically active molecular networks consisting of bacteriophage (phage) directly assembled with gold (Au) nanoparticles (termed Au–phage). We show that when the phage are engineered so that each phage particle displays a peptide, such networks preserve the cell surface receptor binding and internalization attributes of the displayed peptide. The spontaneous organization of these targeted networks can be manipulated further by incorporation of imidazole (Au–phage–imid), which induces changes in fractal structure and near-infrared optical properties. The networks can be used as labels for enhanced fluorescence and dark-field microscopy, surface-enhanced Raman scattering detection, and near-infrared photon-to-heat conversion. Together, the physical and biological features within these targeted networks offer convenient multifunctional integration within a single entity with potential for nanotechnology-based biomedical applications. PMID:16434473

Tracking single-particle rotation during macrophage uptake

DOE PAGES

Sanchez, Lucero; Patton, Paul; Anthony, Stephen Michael; ...

2015-06-10

We investigated the rotational dynamics of single microparticles during their internalization by macrophage cells. The microparticles used were triblock patchy particles that display two fluorescent patches on their two poles. The optical anisotropy made it possible to directly visualize and quantify the orientation and rotation of the particles. We show that particles exhibit a mixture of fast and slow rotation as they are uptaken by macrophages and transiently undergo directional rotation during their entry into the cell. As a result, the size of the particles and the surface presentation of ligands exerted a negligible influence on this heterogeneity of particlemore » rotation.« less

Applications of yeast surface display for protein engineering

PubMed Central

Cherf, Gerald M.; Cochran, Jennifer R.

2015-01-01

The method of displaying recombinant proteins on the surface of Saccharomyces cerevisiae via genetic fusion to an abundant cell wall protein, a technology known as yeast surface display, or simply, yeast display, has become a valuable protein engineering tool for a broad spectrum of biotechnology and biomedical applications. This review focuses on the use of yeast display for engineering protein affinity, stability, and enzymatic activity. Strategies and examples for each protein engineering goal are discussed. Additional applications of yeast display are also briefly presented, including protein epitope mapping, identification of protein-protein interactions, and uses of displayed proteins in industry and medicine. PMID:26060074

Real time thermal imaging for analysis and control of crystal growth by the Czochralski technique

NASA Technical Reports Server (NTRS)

Wargo, M. J.; Witt, A. F.

1992-01-01

A real time thermal imaging system with temperature resolution better than +/- 0.5 C and spatial resolution of better than 0.5 mm has been developed. It has been applied to the analysis of melt surface thermal field distributions in both Czochralski and liquid encapsulated Czochralski growth configurations. The sensor can provide single/multiple point thermal information; a multi-pixel averaging algorithm has been developed which permits localized, low noise sensing and display of optical intensity variations at any location in the hot zone as a function of time. Temperature distributions are measured by extraction of data along a user selectable linear pixel array and are simultaneously displayed, as a graphic overlay, on the thermal image.

CARbodies: Human Antibodies Against Cell Surface Tumor Antigens Selected From Repertoires Displayed on T Cell Chimeric Antigen Receptors

PubMed Central

Alonso-Camino, Vanesa; Sánchez-Martín, David; Compte, Marta; Nuñez-Prado, Natalia; Diaz, Rosa M; Vile, Richard; Alvarez-Vallina, Luis

2013-01-01

A human single-chain variable fragment (scFv) antibody library was expressed on the surface of human T cells after transduction with lentiviral vectors (LVs). The repertoire was fused to a first-generation T cell receptor ζ (TCRζ)-based chimeric antigen receptor (CAR). We used this library to isolate antibodies termed CARbodies that recognize antigens expressed on the tumor cell surface in a proof-of-principle system. After three rounds of activation-selection there was a clear repertoire restriction, with the emergence dominant clones. The CARbodies were purified from bacterial cultures as soluble and active proteins. Furthermore, to validate its potential application for adoptive cell therapy, human T cells were transduced with a LV encoding a second-generation costimulatory CAR (CARv2) bearing the selected CARbodies. Transduced human primary T cells expressed significant levels of the CARbodies-based CARv2 fusion protein on the cell surface, and importantly could be specifically activated, after stimulation with tumor cells. This approach is a promising tool for the generation of antibodies fully adapted to the display format (CAR) and the selection context (cell synapse), which could extend the scope of current adoptive cell therapy strategies with CAR-redirected T cells. PMID:23695536

Improvement of LysM-Mediated Surface Display of Designed Ankyrin Repeat Proteins (DARPins) in Recombinant and Nonrecombinant Strains of Lactococcus lactis and Lactobacillus Species

PubMed Central

Zadravec, Petra; Štrukelj, Borut

2015-01-01

Safety and probiotic properties make lactic acid bacteria (LAB) attractive hosts for surface display of heterologous proteins. Protein display on nonrecombinant microorganisms is preferred for therapeutic and food applications due to regulatory requirements. We displayed two designed ankyrin repeat proteins (DARPins), each possessing affinity for the Fc region of human IgG, on the surface of Lactococcus lactis by fusing them to the Usp45 secretion signal and to the peptidoglycan-binding C terminus of AcmA, containing lysine motif (LysM) repeats. Growth medium containing a secreted fusion protein was used to test its heterologous binding to 10 strains of species of the genus Lactobacillus, using flow cytometry, whole-cell enzyme-linked immunosorbent assay (ELISA), and fluorescence microscopy. The fusion proteins bound to the surfaces of all lactobacilli; however, binding to the majority of bacteria was only 2- to 5-fold stronger than that of the control. Lactobacillus salivarius ATCC 11741 demonstrated exceptionally strong binding (32- to 55-fold higher than that of the control) and may therefore be an attractive host for nonrecombinant surface display. Genomic comparison of the species indicated the exopolysaccharides of Lb. salivarius as a possible reason for the difference. Additionally, a 15-fold concentration-dependent increase in nonrecombinant surface display on L. lactis was demonstrated by growing bacteria with sublethal concentrations of the antibiotics chloramphenicol and erythromycin. Nonrecombinant surface display on LAB, based on LysM repeats, was optimized by selecting Lactobacillus salivarius ATCC 11741 as the optimal host and by introducing antibiotics as additives for increasing surface display on L. lactis. Additionally, effective display of DARPins on the surfaces of nonrecombinant LAB has opened up several new therapeutic possibilities. PMID:25576617

Interface and Electronic Characterization of Thin Epitaxial Co3O4 Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaz, C.A.; Zhu, Y.; Wang, H.-Q.

2009-01-15

The interface and electronic structure of thin ({approx} 20-74 nm) Co{sub 3}O{sub 4}(1 1 0) epitaxial films grown by oxygen-assisted molecular beam epitaxy on MgAl{sub 2}O{sub 4}(1 1 0) single crystal substrates have been investigated by means of real and reciprocal space techniques. As-grown film surfaces are found to be relatively disordered and exhibit an oblique low energy electron diffraction (LEED) pattern associated with the O-rich CoO{sub 2} bulk termination of the (1 1 0) surface. Interface and bulk film structure are found to improve significantly with post-growth annealing at 820 K in air and display sharp rectangular LEED patterns,more » suggesting a surface stoichiometry of the alternative Co{sub 2}O{sub 2} bulk termination of the (1 1 0) surface. Non-contact atomic force microscopy demonstrates the presence of wide terraces separated by atomic steps in the annealed films that are not present in the as-grown structures; the step height of {approx}2.7 {angstrom} corresponds to two atomic layers and confirms a single termination for the annealed films, consistent with the LEED results. A model of the (1 x 1) surfaces that allows for compensation of the polar surfaces is presented.« less

Anomalous three-dimensional bulk ac conduction within the Kondo gap of SmB 6 single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laurita, N. J.; Morris, C. M.; Koohpayeh, S. M.

The Kondo insulator SmB 6 has long been known to display anomalous transport behavior at low temperatures, T < 5 K. In this temperatures range, a plateau is observed in the dc resistivity, contrary to the exponential divergence expected for a gapped system. Some recent theoretical calculations suggest that SmB 6 may be the first topological Kondo insulator (TKI) and propose that the residual conductivity is due to topological surface states which reside within the Kondo gap. Since the TKI prediction many experiments have claimed to observe high mobility surface states within a perfectly insulating hybridization gap. We investigate themore » low energy optical conductivity within the hybridization gap of single crystals of SmB 6 via time domain terahertz spectroscopy. Samples grown by both optical floating zone and aluminum flux methods are investigated to probe for differences originating from sample growth techniques. We find that both samples display significant three-dimensional bulk conduction originating within the Kondo gap. Although SmB 6 may be a bulk dc insulator, it shows significant bulk ac conduction that is many orders of magnitude larger than any known impurity band conduction. The nature of these in-gap states and their coupling with the low energy spin excitons of SmB 6 is discussed. In addition, the well-defined conduction path geometry of our optical experiments allows us to show that any surface states, which lie below our detection threshold if present, must have a sheet resistance of R / square ≥ 1000 Ω .« less

Anomalous three-dimensional bulk ac conduction within the Kondo gap of SmB 6 single crystals

DOE PAGES

Laurita, N. J.; Morris, C. M.; Koohpayeh, S. M.; ...

2016-10-21

The Kondo insulator SmB 6 has long been known to display anomalous transport behavior at low temperatures, T < 5 K. In this temperatures range, a plateau is observed in the dc resistivity, contrary to the exponential divergence expected for a gapped system. Some recent theoretical calculations suggest that SmB 6 may be the first topological Kondo insulator (TKI) and propose that the residual conductivity is due to topological surface states which reside within the Kondo gap. Since the TKI prediction many experiments have claimed to observe high mobility surface states within a perfectly insulating hybridization gap. We investigate themore » low energy optical conductivity within the hybridization gap of single crystals of SmB 6 via time domain terahertz spectroscopy. Samples grown by both optical floating zone and aluminum flux methods are investigated to probe for differences originating from sample growth techniques. We find that both samples display significant three-dimensional bulk conduction originating within the Kondo gap. Although SmB 6 may be a bulk dc insulator, it shows significant bulk ac conduction that is many orders of magnitude larger than any known impurity band conduction. The nature of these in-gap states and their coupling with the low energy spin excitons of SmB 6 is discussed. In addition, the well-defined conduction path geometry of our optical experiments allows us to show that any surface states, which lie below our detection threshold if present, must have a sheet resistance of R / square ≥ 1000 Ω .« less

Tangible display systems: bringing virtual surfaces into the real world

NASA Astrophysics Data System (ADS)

Ferwerda, James A.

2012-03-01

We are developing tangible display systems that enable natural interaction with virtual surfaces. Tangible display systems are based on modern mobile devices that incorporate electronic image displays, graphics hardware, tracking systems, and digital cameras. Custom software allows the orientation of a device and the position of the observer to be tracked in real-time. Using this information, realistic images of surfaces with complex textures and material properties illuminated by environment-mapped lighting, can be rendered to the screen at interactive rates. Tilting or moving in front of the device produces realistic changes in surface lighting and material appearance. In this way, tangible displays allow virtual surfaces to be observed and manipulated as naturally as real ones, with the added benefit that surface geometry and material properties can be modified in real-time. We demonstrate the utility of tangible display systems in four application areas: material appearance research; computer-aided appearance design; enhanced access to digital library and museum collections; and new tools for digital artists.

Engineering RNA phage MS2 virus-like particles for peptide display

NASA Astrophysics Data System (ADS)

Jordan, Sheldon Keith

Phage display is a powerful and versatile technology that enables the selection of novel binding functions from large populations of randomly generated peptide sequences. Random sequences are genetically fused to a viral structural protein to produce complex peptide libraries. From a sufficiently complex library, phage bearing peptides with practically any desired binding activity can be physically isolated by affinity selection, and, since each particle carries in its genome the genetic information for its own replication, the selectants can be amplified by infection of bacteria. For certain applications however, existing phage display platforms have limitations. One such area is in the field of vaccine development, where the goal is to identify relevant epitopes by affinity-selection against an antibody target, and then to utilize them as immunogens to elicit a desired antibody response. Today, affinity selection is usually conducted using display on filamentous phages like M13. This technology provides an efficient means for epitope identification, but, because filamentous phages do not display peptides in the high-density, multivalent arrays the immune system prefers to recognize, they generally make poor immunogens and are typically useless as vaccines. This makes it necessary to confer immunogenicity by conjugating synthetic versions of the peptides to more immunogenic carriers. Unfortunately, when introduced into these new structural environments, the epitopes often fail to elicit relevant antibody responses. Thus, it would be advantageous to combine the epitope selection and immunogen functions into a single platform where the structural constraints present during affinity selection can be preserved during immunization. This dissertation describes efforts to develop a peptide display system based on the virus-like particles (VLPs) of bacteriophage MS2. Phage display technologies rely on (1) the identification of a site in a viral structural protein that is present on the surface of the virus particle and can accept foreign sequence insertions without disruption of protein folding and viral particle assembly, and (2) on the encapsidation of nucleic acid sequences encoding both the VLP and the peptide it displays. The experiments described here are aimed at satisfying the first of these two requirements by engineering efficient peptide display at two different sites in MS2 coat protein. First, we evaluated the suitability of the N-terminus of MS2 coat for peptide insertions. It was observed that random N-terminal 10-mer fusions generally disrupted protein folding and VLP assembly, but by bracketing the foreign sequences with certain specific dipeptides, these defects could be suppressed. Next, the suitability of a coat protein surface loop for foreign sequence insertion was tested. Specifically, random sequence peptides were inserted into the N-terminal-most AB-loop of a coat protein single-chain dimer. Again we found that efficient display required the presence of appropriate dipeptides bracketing the peptide insertion. Finally, it was shown that an N-terminal fusion that tended to interfere specifically with capsid assembly could be efficiently incorporated into mosaic particles when co-expressed with wild-type coat protein.

Display technologies: application for the discovery of drug and gene delivery agents

PubMed Central

Sergeeva, Anna; Kolonin, Mikhail G.; Molldrem, Jeffrey J.; Pasqualini, Renata; Arap, Wadih

2007-01-01

Recognition of molecular diversity of cell surface proteomes in disease is essential for the development of targeted therapies. Progress in targeted therapeutics requires establishing effective approaches for high-throughput identification of agents specific for clinically relevant cell surface markers. Over the past decade, a number of platform strategies have been developed to screen polypeptide libraries for ligands targeting receptors selectively expressed in the context of various cell surface proteomes. Streamlined procedures for identification of ligand-receptor pairs that could serve as targets in disease diagnosis, profiling, imaging and therapy have relied on the display technologies, in which polypeptides with desired binding profiles can be serially selected, in a process called biopanning, based on their physical linkage with the encoding nucleic acid. These technologies include virus/phage display, cell display, ribosomal display, mRNA display and covalent DNA display (CDT), with phage display being by far the most utilized. The scope of this review is the recent advancements in the display technologies with a particular emphasis on molecular mapping of cell surface proteomes with peptide phage display. Prospective applications of targeted compounds derived from display libraries in the discovery of targeted drugs and gene therapy vectors are discussed. PMID:17123658

Obligate multivalent recognition of cell surface tomoregulin following selection from a multivalent phage antibody library.

PubMed

Heitner, Tara; Satozawa, Noboru; McLean, Kirk; Vogel, David; Cobb, Ronald R; Liu, Bing; Mahmoudi, Mithra; Finster, Silke; Larsen, Brent; Zhu, Ying; Zhou, Hongxing; Müller-Tiemann, Beate; Monteclaro, Felipe; Zhao, Xiao-Yan; Light, David R

2006-12-01

A therapeutic antibody candidate (AT-19) isolated using multivalent phage display binds native tomoregulin (TR) as a mul-timer not as a monomer. This report raises the importance of screening and selecting phage antibodies on native antigen and reemphasizes the possibility that potentially valuable antibodies are discarded when a monomeric phage display system is used for screening. A detailed live cell panning selection and screening method to isolate multivalently active antibodies is described. AT-19 is a fully human antibody recognizing the cell surface protein TR, a proposed prostate cancer target for therapeutic antibody internalization. AT-19 was isolated from a multivalent single-chain variable fragment (scFv) antibody library rescued with hyperphage. The required multivalency for isolation of AT-19 is supported by fluorescence activated cell sorting data demonstrating binding of the multivalent AT-19 phage particles at high phage concentrations and failure of monovalent particles to bind. Pure monomeric scFv AT-19 does not bind native receptor on cells, whereas dimeric scFv or immunoglobulin G binds with nanomolar affinity. The isolation of AT-19 antibody with obligate bivalent binding activity to native TR is attributed to the use of a multivalent display of scFv on phage and the method for selecting and screening by alternate use of 2 recombinant cell lines.

Yeast cell surface display: An efficient strategy for improvement of bioethanol fermentation performance.

PubMed

Chen, Xianzhong

2017-03-04

The cell surface serves as a functional interface between the inside and the outside of the cell. Within the past 20 y the ability of yeast (Saccharomyces cerevisiae) to display heterologous proteins on the cell surface has been demonstrated. Furthermore, S. cerevisiae has been both developed and applied in expression of various proteins on the cell surface. Using this novel and useful strategy, proteins and peptides of various kinds can be displayed on the yeast cell surface by fusing the protein of interest with the glycosylphosphatidylinositol (GPI)-anchoring system. Consolidated bioprocessing (CBP) using S. cerevisiae represents a promising technology for bioethanol production. However, further work is needed to improve the fermentation performance. There is some excellent previous research regarding construction of yeast biocatalyst using the surface display system to decrease cost, increase efficiency of ethanol production and directly utilize starch or biomass for fuel production. In this commentary, we reviewed the yeast surface display system and highlighted recent work. Additionally, the strategy for decrease of phytate phosphate content in dried distillers grains with solubles (DDGS) by display of phytase on the yeast cell surface is discussed.

Yeast cell surface display: An efficient strategy for improvement of bioethanol fermentation performance

PubMed Central

Chen, Xianzhong

2017-01-01

ABSTRACT The cell surface serves as a functional interface between the inside and the outside of the cell. Within the past 20 y the ability of yeast (Saccharomyces cerevisiae) to display heterologous proteins on the cell surface has been demonstrated. Furthermore, S. cerevisiae has been both developed and applied in expression of various proteins on the cell surface. Using this novel and useful strategy, proteins and peptides of various kinds can be displayed on the yeast cell surface by fusing the protein of interest with the glycosylphosphatidylinositol (GPI)-anchoring system. Consolidated bioprocessing (CBP) using S. cerevisiae represents a promising technology for bioethanol production. However, further work is needed to improve the fermentation performance. There is some excellent previous research regarding construction of yeast biocatalyst using the surface display system to decrease cost, increase efficiency of ethanol production and directly utilize starch or biomass for fuel production. In this commentary, we reviewed the yeast surface display system and highlighted recent work. Additionally, the strategy for decrease of phytate phosphate content in dried distillers grains with solubles (DDGS) by display of phytase on the yeast cell surface is discussed. PMID:27459271

Single layer multi-color luminescent display and method of making

NASA Technical Reports Server (NTRS)

Robertson, James B. (Inventor)

1992-01-01

The invention is a multi-color luminescent display comprising an insulator substrate and a single layer of host material, which may be a phosphor deposited thereon that hosts one or more different impurities, therein forming a pattern of selected and distinctly colored phosphors such as blue, green, and red phosphors in a single layer of host material. Transparent electrical conductor means may be provided for subjecting selected portions of the pattern of colored phosphors to an electric field, thereby forming a multi-color, single layer electroluminescent display. A method of forming a multi-color luminescent display includes the steps of depositing on an insulator substrate a single layer of host material, which itself may be a phosphor, with the properties to host varying quantities of different impurities and introducing one or more of said different impurities into selected areas of the said single layer of host material by thermal diffusion or ion implantation to form a pattern of phosphors of different colors in the said single layer of host material.

Single particle tracking reveals spatial and dynamic organization of the Escherichia coli biofilm matrix

NASA Astrophysics Data System (ADS)

Birjiniuk, Alona; Billings, Nicole; Nance, Elizabeth; Hanes, Justin; Ribbeck, Katharina; Doyle, Patrick S.

2014-08-01

Biofilms are communities of surface-adherent bacteria surrounded by secreted polymers known as the extracellular polymeric substance. Biofilms are harmful in many industries, and thus it is of great interest to understand their mechanical properties and structure to determine ways to destabilize them. By performing single particle tracking with beads of varying surface functionalization it was found that charge interactions play a key role in mediating mobility within biofilms. With a combination of single particle tracking and microrheological concepts, it was found that Escherichia coli biofilms display height dependent charge density that evolves over time. Statistical analyses of bead trajectories and confocal microscopy showed inter-connecting micron scale channels that penetrate throughout the biofilm, which may be important for nutrient transfer through the system. This methodology provides significant insight into a particular biofilm system and can be applied to many others to provide comparisons of biofilm structure. The elucidation of structure provides evidence for the permeability of biofilms to microscale objects, and the ability of a biofilm to mature and change properties over time.

Polychromatic plots: graphical display of multidimensional data.

PubMed

Roederer, Mario; Moody, M Anthony

2008-09-01

Limitations of graphical displays as well as human perception make the presentation and analysis of multidimensional data challenging. Graphical display of information on paper or by current projectors is perforce limited to two dimensions; the encoding of information from other dimensions must be overloaded into the two physical dimensions. A number of alternative means of encoding this information have been implemented, such as offsetting data points at an angle (e.g., three-dimensional projections onto a two-dimensional surface) or generating derived parameters that are combinations of other variables (e.g., principal components). Here, we explore the use of color to encode additional dimensions of data. PolyChromatic Plots are standard dot plots, where the color of each event is defined by the values of one, two, or three of the measurements for that event. The measurements for these parameters are mapped onto an intensity value for each primary color (red, green, or blue) based on different functions. In addition, differential weighting of the priority with which overlapping events are displayed can be defined by these same measurements. PolyChromatic Plots can encode up to five independent dimensions of data in a single display. By altering the color mapping function and the priority function, very different displays that highlight or de-emphasize populations of events can be generated. As for standard black-and-white dot plots, frequency information can be significantly biased by this display; care must be taken to ensure appropriate interpretation of the displays. PolyChromatic Plots are a powerful display type that enables rapid data exploration. By virtue of encoding as many as five dimensions of data independently, an enormous amount of information can be gleaned from the displays. In many ways, the display performs somewhat like an unsupervised cluster algorithm, by highlighting events of similar distributions in multivariate space.

EMU helmet mounted display

NASA Technical Reports Server (NTRS)

Marmolejo, Jose (Inventor); Smith, Stephen (Inventor); Plough, Alan (Inventor); Clarke, Robert (Inventor); Mclean, William (Inventor); Fournier, Joseph (Inventor)

1990-01-01

A helmet mounted display device is disclosed for projecting a display on a flat combiner surface located above the line of sight where the display is produced by two independent optical channels with independent LCD image generators. The display has a fully overlapped field of view on the combiner surface and the focus can be adjusted from a near field of four feet to infinity.

Re-Imagining Archival Display: Creating User-Friendly Finding Aids

ERIC Educational Resources Information Center

Daines, J. Gordon, III; Nimer, Cory L.

2011-01-01

This article examines how finding aids are structured and delivered, considering alternative approaches. It suggests that single-level displays, those that present a single component of a multilevel description to users at a time, have the potential to transform the delivery and display of collection information while improving the user…

Electrokinetic Response of Charge-Selective Nanostructured Polymeric Membranes

NASA Astrophysics Data System (ADS)

Schiffbauer, Jarrod; Li, Diya; Gao, Feng; Phillip, William; Chang, Hsueh-Chia

2017-11-01

Nanostructured polymeric membranes, with a tunable pore size and ease of surface molecular functionalization, are a promising material for separations, filtration, and sensing applications. Recently, such membranes have been fabricated wherein the ion selectivity is imparted by self-assembled functional groups through a two-step process. Amine groups are used to provide a positive surface charge and acid groups are used to yield a negative charge. The membranes can be fabricated as either singly-charged or patterned/mosaic membranes, where there are alternating regions of amine- lined or acid-lined pores. We demonstrate that such membranes, in addition to having many features in common with other charge selective membranes (i.e. AMX or Nafion), display a unique single-membrane rectification behavior. This is due to the asymmetric distribution of charged functional groups during the fabrication process. We demonstrate this rectification effect using both dc current-voltage characteristics as well as dc-biased electrical impedance spectroscopy. Furthermore, surface charge changes due to dc concentration polarization and generation of localized pH shifts are monitored using electrical impedance spectroscopy. (formerly at University of Notre Dame).

Plasmonic detection of mercury via amalgam formation on surface-immobilized single Au nanorods

NASA Astrophysics Data System (ADS)

Schopf, Carola; Martín, Alfonso; Iacopino, Daniela

2017-12-01

Au nanorods were used as plasmonic transducers for investigation of mercury detection through a mechanism of amalgam formation at the nanorod surfaces. Marked scattering color transitions and associated blue shifts of the surface plasmon resonance peak wavelengths (λmax) were measured in individual nanorods by darkfield microscopy upon chemical reduction of Hg(II). Such changes were related to compositional changes occurring as a result of Hg-Au amalgam formation as well as morphological changes in the nanorods' aspect ratios. The plot of λmax shifts vs. Hg(II) concentration showed a linear response in the 10-100 nM concentration range. The sensitivity of the system was ascribed to the narrow width of single nanorod scattering spectra, which allowed accurate determination of peak shifts. The system displayed good selectivity as the optical response obtained for mercury was one order of magnitude higher than the response obtained with competitor ions. Analysis of mercury content in river and tap water were also performed and highlighted both the potential and limitation of the developed method for real sensing applications.

Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules.

PubMed

Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan; Temirov, Ruslan

2015-01-01

Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926-1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface.

Finishing of display glass for mobile electronics using 3M Trizact diamond tile abrasive pads

NASA Astrophysics Data System (ADS)

Zheng, Lianbin; Fletcher, Tim; Na, Tee Koon; Sventek, Bruce; Romero, Vince; Lugg, Paul S.; Kim, Don

2010-10-01

This paper will describe a new method being used during the finishing of glass displays for mobile electronics including mobile hand held devices and notebook computers. The new method consists of using 3M TrizactTM Diamond Tile Abrasive Pads. TrizactTM Diamond Tile is a structured fixed abrasive grinding technology developed by 3M Company. The TrizactTM Diamond Tile structured abrasive pad consists of an organic (polymeric binder) - inorganic (abrasive mineral, i.e., diamond) composite that is used with a water-based coolant. TrizactTM Diamond Tile technology can be applied in both double and single side grinding applications. A unique advantage of TrizactTM Diamond Tile technology is the combination of high stock removal and low sub-surface damage. Grinding results will be presented for both 9 micron and 20 micron grades of TrizactTM Diamond Tile abrasive pads used to finish several common display glasses including Corning GorillaTM glass and Soda Lime glass.

Search for Past Life on Mars: Possible Relict Biogenic Activity in Martian Meteorite ALH84001

NASA Technical Reports Server (NTRS)

McKay, David S.; Gibson, Everett K., Jr.; Thomas-Keprta, Kathie L.; Vali, Hojatollah; Romanek, Christopher S.; Clemett, Simon J.; Chillier, Xavier D. F.; Maechling, Claude R.; Zare, Richard N.

1996-01-01

Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest the PAHs are indigenous to the meteorite. High resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globules show that the globules contain fine-grained, secondary phases of single-domain magnetite and Fe-monosulfides. The carbonate globules are similar in texture and size to some terrestrial bacterially induced carbonate precipitates. Although inorganic formation is possible, formation of the globules by biogenic processes could explain many of the observed features including the PAHs. The PAHs, the carbonate globules, and their associated secondary mineral phases and textures could thus be fossil remains of a past martian biota.

Coverage Dependent Assembly of Anthraquinone on Au(111)

NASA Astrophysics Data System (ADS)

Conrad, Brad; Deloach, Andrew; Einstein, Theodore; Dougherty, Daniel

A study of adsorbate-adsorbate and surface state mediated interactions of anthraquinone (AnQ) on Au(111) is presented. We utilize scanning tunneling microscopy (STM) to characterize the coverage dependence of AnQ structure formation. Ordered structures are observed up to a single monolayer (ML) and are found to be strongly dependent on molecular surface density. While the complete ML forms a well-ordered close-packed layer, for a narrow range of sub-ML coverages irregular close-packed islands are observed to coexist with a disordered pore network linking neighboring islands. This network displays a characteristic pore size and at lower coverages, the soliton walls of the herringbone reconstruction are shown to promote formation of distinct pore nanostructures. We will discuss these nanostructure formations in the context of surface mediated and more direct adsorbate interactions.

Surface colour photometry of galaxies with Schmidt telescopes.

NASA Technical Reports Server (NTRS)

Wray, J. D.

1972-01-01

A method is described which owes its practicality to the capability of Schmidt telescopes to record a number of galaxy images on a single plate and to the existence of high speed computer controlled area-scanning precision microdensitometers such as the Photometric Data Systems model 1010. The method of analysis results in quantitative color-index information which is displayed in a manner that allows any user to effectively study the morphological properties of the distribution of color-index in galaxies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auciello, O.; Ameen, M.S.; Graettinger, T.M.

Ion beam sputtering is presently used to deposit films from single phase YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} targets. Generally, Ar+ ion beams ({approx}1500 eV) produced by Kaufman-type ion sources are used for this purpose. It has been observed that these ion beams induce compositional and morphological changes on the polycrystalline ceramic target surface, which results in the composition of sputtered flux displaying a time-dependent behavior. This in turn may lead to undesirably long times for reaching steady state conditions in the sputtering process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auciello, O.; Ameen, M.S.; Graettinger, T.

Ion beam sputtering is presently used to deposit films from single phase YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} targets. Generally, Ar{sup +} ion beams ({similar to}1500 eV) produced by Kaufman-type ion sources are used for this purpose. It has been observed that these ion beams induce compositional and morphological changes on the polycrystalline ceramic target surface, which results in the composition of sputtered flux displaying a time-dependent behavior. This in turn may lead to undesirably long times for reaching steady state conditions in the sputtering process.

Spatial Attention Enhances Perceptual Processing of Single-Element Displays

NASA Technical Reports Server (NTRS)

Bacon, William; Johnston, James C.; Remington, Roger W.; Null, Cynthia H. (Technical Monitor)

1994-01-01

Shiu and Pashler (1993) reported that precueing masked, single-element displays had negligible effects on identification accuracy. They argued that spatial attention does not actually enhance stimulus perceptibility, but only reduces decision noise. Alternatively, such negative results may arise if cues are sub-optimal, or if masks place an insufficient premium on timely deployment of attention. We report results showing that valid cueing enhances processing of even single-element displays. Spatial attention does indeed enhance perceptual processes.

Combining Phage and Yeast Cell Surface Antibody Display to Identify Novel Cell Type-Selective Internalizing Human Monoclonal Antibodies.

PubMed

Bidlingmaier, Scott; Su, Yang; Liu, Bin

2015-01-01

Using phage antibody display, large libraries can be generated and screened to identify monoclonal antibodies with affinity for target antigens. However, while library size and diversity is an advantage of the phage display method, there is limited ability to quantitatively enrich for specific binding properties such as affinity. One way of overcoming this limitation is to combine the scale of phage display selections with the flexibility and quantitativeness of FACS-based yeast surface display selections. In this chapter we describe protocols for generating yeast surface antibody display libraries using phage antibody display selection outputs as starting material and FACS-based enrichment of target antigen-binding clones from these libraries. These methods should be widely applicable for the identification of monoclonal antibodies with specific binding properties.

A new helper phage for improved monovalent display of Fab molecules.

PubMed

Beaber, John W; Tam, Eric M; Lao, Llewelyn S; Rondon, Isaac J

2012-02-28

Phage display technology is a powerful tool for the identification of novel antibodies for drug discovery. Phage display libraries have been constructed with massive diversity, but their use may be hindered by limited antibody display levels when rescued with the M13KO7 helper phage. Variants of M13KO7 have been constructed previously that increase the levels of display of rescued phage, but all produce phage that display multiple copies of the antibody fragment on their surface and have reduced titer and infectivity. In this study, we describe a new helper phage, XP5, which increased the display level of Fab molecules more than two-fold compared to phage rescued with M13KO7. XP5 uses a combination of ribosome binding site spacing alterations and rare codon clusters to reduce the expression of pIII from the helper phage. This reduction in pIII expression leads to an increase in the incorporation of pIII-Fab fusions during phage rescue. The rescued phage displayed a single copy of the Fab molecule, preventing any avidity effects during the selection process. This also suggests that the percentage of the population of phage displaying a Fab molecule is increased when rescued with XP5. Additionally, the phage titers and infectivity are comparable to libraries rescued with M13KO7. After two rounds of panning we observed a nearly 5-fold increase in the number of antigen binding Fab molecules compared to panning conducted with the same library rescued with M13KO7. The nature of the mutations in XP5 makes it a universal substitute for M13KO7 in pIII-based phage display, compatible with most phagemids and bacterial strains. Copyright © 2011 Elsevier B.V. All rights reserved.

EM-ANIMATE - COMPUTER PROGRAM FOR DISPLAYING AND ANIMATING THE STEADY-STATE TIME-HARMONIC ELECTROMAGNETIC NEAR FIELD AND SURFACE-CURRENT SOLUTIONS

NASA Technical Reports Server (NTRS)

Hom, K. W.

1994-01-01

The EM-ANIMATE program is a specialized visualization program that displays and animates the near-field and surface-current solutions obtained from an electromagnetics program, in particular, that from MOM3D (LAR-15074). The EM-ANIMATE program is windows based and contains a user-friendly, graphical interface for setting viewing options, case selection, file manipulation, etc. EM-ANIMATE displays the field and surface-current magnitude as smooth shaded color fields (color contours) ranging from a minimum contour value to a maximum contour value for the fields and surface currents. The program can display either the total electric field or the scattered electric field in either time-harmonic animation mode or in the root mean square (RMS) average mode. The default setting is initially set to the minimum and maximum values within the field and surface current data and can be optionally set by the user. The field and surface-current value are animated by calculating and viewing the solution at user selectable radian time increments between 0 and 2pi. The surface currents can also be displayed in either time-harmonic animation mode or in RMS average mode. In RMS mode, the color contours do not vary with time, but show the constant time averaged field and surface-current magnitude solution. The electric field and surface-current directions can be displayed as scaled vector arrows which have a length proportional to the magnitude at each field grid point or surface node point. These vector properties can be viewed separately or concurrently with the field or surface-current magnitudes. Animation speed is improved by turning off the display of the vector arrows. In RMS modes, the direction vectors are still displayed as varying with time since the time averaged direction vectors would be zero length vectors. Other surface properties can optionally be viewed. These include the surface grid, the resistance value assigned to each element of the grid, and the power dissipation of each element which has an assigned resistance value. The EM-ANIMATE program will accept up to 10 different surface current cases each consisting of up to 20,000 node points and 10,000 triangle definitions and will animate one of these cases. The capability is used to compare surface-current distribution due to various initial excitation directions or electric field orientations. The program can accept up to 50 planes of field data consisting of a grid of 100 by 100 field points. These planes of data are user selectable and can be viewed individually or concurrently. With these preset limits, the program requires 55 megabytes of core memory to run. These limits can be changed in the header files to accommodate the available core memory of an individual workstation. An estimate of memory required can be made as follows: approximate memory in bytes equals (number of nodes times number of surfaces times 14 variables times bytes per word, typically 4 bytes per floating point) plus (number of field planes times number of nodes per plane times 21 variables times bytes per word). This gives the approximate memory size required to store the field and surface-current data. The total memory size is approximately 400,000 bytes plus the data memory size. The animation calculations are performed in real time at any user set time step. For Silicon Graphics Workstations that have multiple processors, this program has been optimized to perform these calculations on multiple processors to increase animation rates. The optimized program uses the SGI PFA (Power FORTRAN Accelerator) library. On single processor machines, the parallelization directives are seen as comments to the program and will have no effect on compilation or execution. EM-ANIMATE is written in FORTRAN 77 for implementation on SGI IRIS workstations running IRIX 3.0 or later. A minimum of 55Mb of RAM is required for execution of this program; however, the code may be modified to accommodate the available memory of an individual workstation. For program execution, twenty-four bit, double-buffered color capability is suggested, but not required. Sample input and output files and a sample executable are provided on the distribution medium. Electronic documentation is provided in PostScript format and in the form of IRIX man pages. The standard distribution medium for EM-ANIMATE is a .25 inch streaming magnetic IRIX tape cartridge in UNIX tar format. EM-ANIMATE is also available as part of a bundled package, COS-10048 that includes MOM3D, an IRIS program that produces electromagnetic near field and surface current solutions. This program was developed in 1993.

Yeast cell surface display for lipase whole cell catalyst and its applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yun; Zhang, Rui; Lian, Zhongshuai

The cell surface display technique allows for the expression of target proteins or peptides on the microbial cell surface by fusing an appropriate protein as an anchoring motif. Yeast display systems, such as Pichia pastoris, Yarowia lipolytica and Saccharomyces cerevisiae, are ideal, alternative and extensive display systems with the advantage of simple genetic manipulation and post-translational modification of expressed heterologous proteins. Engineered yeasts show high performance characteristics and variant utilizations. Herein, we comprehensively summarize the variant factors affecting lipase whole cell catalyst activity and display efficiency, including the structure and size of target proteins, screening anchor proteins, type and chainmore » length of linkers, and the appropriate matching rules among the above-mentioned display units. Furthermore, we also address novel approaches to enhance stability and activity of recombinant lipases, such as VHb gene co-expression, multi-enzyme co-display technique, and the micro-environmental interference and self-assembly techniques. Finally, we represent the variety of applications of whole cell surface displayed lipases on yeast cells in non-aqueous phases, including synthesis of esters, PUFA enrichment, resolution of chiral drugs, organic synthesis and biofuels. We demonstrate that the lipase surface display technique is a powerful tool for functionalizing yeasts to serve as whole cell catalysts, and increasing interest is providing an impetus for broad application of this technique.« less

Crystal step edges can trap electrons on the surfaces of n-type organic semiconductors.

PubMed

He, Tao; Wu, Yanfei; D'Avino, Gabriele; Schmidt, Elliot; Stolte, Matthias; Cornil, Jérôme; Beljonne, David; Ruden, P Paul; Würthner, Frank; Frisbie, C Daniel

2018-05-30

Understanding relationships between microstructure and electrical transport is an important goal for the materials science of organic semiconductors. Combining high-resolution surface potential mapping by scanning Kelvin probe microscopy (SKPM) with systematic field effect transport measurements, we show that step edges can trap electrons on the surfaces of single crystal organic semiconductors. n-type organic semiconductor crystals exhibiting positive step edge surface potentials display threshold voltages that increase and carrier mobilities that decrease with increasing step density, characteristic of trapping, whereas crystals that do not have positive step edge surface potentials do not have strongly step density dependent transport. A device model and microelectrostatics calculations suggest that trapping can be intrinsic to step edges for crystals of molecules with polar substituents. The results provide a unique example of a specific microstructure-charge trapping relationship and highlight the utility of surface potential imaging in combination with transport measurements as a productive strategy for uncovering microscopic structure-property relationships in organic semiconductors.

Method of forming crystalline silicon devices on glass

DOEpatents

McCarthy, Anthony M.

1995-01-01

A method for fabricating single-crystal silicon microelectronic components on a silicon substrate and transferring same to a glass substrate. This is achieved by utilizing conventional silicon processing techniques for fabricating components of electronic circuits and devices on bulk silicon, wherein a bulk silicon surface is prepared with epitaxial layers prior to the conventional processing. The silicon substrate is bonded to a glass substrate and the bulk silicon is removed leaving the components intact on the glass substrate surface. Subsequent standard processing completes the device and circuit manufacturing. This invention is useful in applications requiring a transparent or insulating substrate, particularly for display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard electronics, and high temperature electronics.

Testing Instrument for Flight-Simulator Displays

NASA Technical Reports Server (NTRS)

Haines, Richard F.

1987-01-01

Displays for flight-training simulators rapidly aligned with aid of integrated optical instrument. Calibrations and tests such as aligning boresight of display with respect to user's eyes, checking and adjusting display horizon, checking image sharpness, measuring illuminance of displayed scenes, and measuring distance of optical focus of scene performed with single unit. New instrument combines all measurement devices in single, compact, integrated unit. Requires just one initial setup. Employs laser and produces narrow, collimated beam for greater measurement accuracy. Uses only one moving part, double right prism, to position laser beam.

A three-dimensional microelectrode array composed of vertically aligned ultra-dense carbon nanotube networks

NASA Astrophysics Data System (ADS)

Nick, C.; Yadav, S.; Joshi, R.; Schneider, J. J.; Thielemann, C.

2015-07-01

Electrodes based on carbon nanotubes are a promising approach to manufacture highly sensitive sensors with a low limit of signal detection and a high signal-to-noise ratio. This is achieved by dramatically increasing the electrochemical active surface area without increasing the overall geometrical dimensions. Typically, carbon nanotube electrodes are nearly planar and composed of randomly distributed carbon nanotube networks having a limited surface gain for a specific geometrical surface area. To overcome this limitation, we have introduced vertically aligned carbon nanotube (VACNT) networks as electrodes, which are arranged in a microelectrode pattern of 60 single electrodes. Each microelectrode features a very high aspect ratio of more than 300 and thus a dramatically increased surface area. These microelectrodes composed of VACNT networks display dramatically decreased impedance over the entire frequency range compared to planar microelectrodes caused by the enormous capacity increase. This is experimentally verified by electrochemical impedance spectroscopy and cyclic voltammetry.

Magnetic electroanatomical mapping for ablation of focal atrial tachycardias.

PubMed

Marchlinski, F; Callans, D; Gottlieb, C; Rodriguez, E; Coyne, R; Kleinman, D

1998-08-01

Uniform success for ablation of focal atrial tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology, and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system (CARTO) offers an on-line display of electrical activation and/or signal amplitude related to the anatomical location of the recorded sites in the mapped chamber. A window of electrical interest is established based on signals timed from an electrical reference that usually represents a fixed electrogram recording from the coronary sinus or the atrial appendage. This window of electrical interest is established to include atrial activation prior to the onset of the P wave activity associated with the site of origin of a focal atrial tachycardia. Anatomical and electrical landmarks are defined with limited fluoroscopic imaging support and more detailed global chamber and more focal atrial mapping can be performed with minimal fluoroscopic guidance. A three-dimensional color map representing atrial activation or voltage amplitude at the magnetically defined anatomical sites is displayed with on-line data acquisition. This display can be manipulated to facilitate viewing from any angle. Altering the zoom control, triangle fill threshold, clipping plane, or color range can all enhance the display of a more focal area of interest. We documented the feasibility of using this single mapping catheter technique for localizing and ablating focal atrial tachycardias. In a consecutive series of 8 patients with 9 focal atrial tachycardias, the use of the single catheter CARTO mapping system was associated with ablation success in all but one patient who had a left atrial tachycardia localized to the medial aspect of the orifice of the left atrial appendage. Only low power energy delivery was used in this patient because of the unavailability of temperature monitoring in the early version of the Navistar catheter, the location of the arrhythmia, and the history of arrhythmia control with flecainide. No attempt was made to limit fluoroscopy time in our study population. Nevertheless, despite data acquisition from 120-320 anatomically distinct sites during global and more detailed focal atrial mapping, total fluoroscopy exposure was typically < 30 minutes and was as little as 12 minutes. The detailed display capabilities of the CARTO system appear to offer the potential of enhancing our understanding of atrial anatomy, atrial activation, and their relationship to surface ECG P wave morphology during focal atrial tachycardias.

Design of Single-Site Photocatalyst using Metal-Organic Framework as Matrix.

PubMed

Wen, Meicheng; Mori, Kohsuke; Kuwahara, Yasutaka; An, Taicheng; Yamashita, Hiromi

2018-05-14

Single-site photocatalyst generally displays excellent photocatalytic activtiy and considerable high stability as compared to homogeneous catalytic system. A rational structural design of single-site photocatalyst with isolated, uniform and spatially separated active sites in a given solid is of prime importance to achieve high photocatalytic activity. Intense attentions have been focused on the engineering and fabrication of single-site photocatalys by using porous materials as platform. Metal-organic frameworks (MOFs) hold great potential for the design and fabrication of single-site photocatalysts due to their remarkable porosity, ultrahigh surface area, extraordinary tailorability and significant diversity. MOFs can provide abundant number of binding sites for anchoring active sites, result in significant enhancement of photocatalytic performance. In this focus review, the development of single-site MOF photocatalysts that perform in important and challenging chemical redox reaction such as photocatalytic water splitting, photocatalytic CO₂ conversion and organic transformations is summarized thoroughly. The successful strategies applied for the construction of single-site MOF photocatalysts and major challenge toward practical application was summarized and pointed out, respectively. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave-assisted synthesis of Pt/CNT nanocomposite electrocatalysts for PEM fuel cells.

PubMed

Zhang, Weimin; Chen, Jun; Swiegers, Gerhard F; Ma, Zi-Feng; Wallace, Gordon G

2010-02-01

Microwave-assisted heating of functionalized, single-wall carbon nanotubes (FCNTs) in ethylene glycol solution containing H(2)PtCl(6), led to the reductive deposition of Pt nanoparticles (2.5-4 nm) over the FCNTs, yielding an active catalyst for proton-exchange membrane fuel cells (PEMFCs). In single-cell testing, the Pt/FCNT composites displayed a catalytic performance that was superior to Pt nanoparticles supported by raw (unfunctionalized) CNTs (RCNTs) or by carbon black (C), prepared under identical conditions. The supporting single-wall carbon nanotubes (SWNTs), functionalized with carboxyl groups, were studied by thermogravimetric analysis (TGA), cyclic voltammetry (CV), and Raman spectroscopy. The loading level, morphology, and crystallinity of the Pt/SWNT catalysts were determined using TGA, SEM, and XRD. The electrochemically active catalytic surface area of the Pt/FCNT catalysts was 72.9 m(2)/g-Pt.

Multiscale study of mononuclear Co II SMMs based on curcuminoid ligands

DOE PAGES

Díaz-Torres, Raúl; Menelaou, Melita; Roubeau, Olivier; ...

2016-01-07

This work introduces a novel family of Co II species having a curcuminoid (CCMoid) ligand, 9Accm, attached, namely [Co(9Accm) 2 (py) 2 ] (1) and [Co(9Accm) 2(2,2'-bpy)] (2), achieved in high yields by the use of a microwave reactor, and exhibiting two different arrangements for the 9Accm ligands, described as "cis"(2) and "trans"(1). The study of the similarities/differences of the magnetic, luminescent and surface behaviors of the two new species, 1 and 2, is the main objective of the present work. The determined single-crystal structures of both compounds are the only Co II -CCMoid structures described in the literature somore » far. Both compounds exhibit large positive D values, that of 1 (D = +74 cm -1 ) being three times larger than that of 2 (D = +24 cm -1 ), and behave as mononuclear Single-Molecule Magnets (SMMs) in the presence of an external magnetic field. Their similar structures but different anisotropy and SMM characteristics provide, for the first time, deep insight on the spin-orbital effects thanks to the use of CASSCF/NEVPT2 calculations implementing such contributions. Further magnetic studies were performed in solution by means of paramagnetic 1H NMR, where both compounds (1 and 2) are stable in CDCl 3 and display high symmetry. Paramagnetic NMR appears to be a useful diagnostic tool for the identification of such molecules in solution, where the resonance values found for the methine group (-CH-) of 9Accm vary significantly depending on the cis or trans disposition of the ligands. Fluorescence studies show that both systems display chelation enhancement of quenching (CHEQ) with regard to the free ligand, while 1 and 2 display similar quantum yields. Deposition of 1-2 on HOPG and Si(100) surfaces using spin-coating was studied using AFM; UV photoemission experiments under the same conditions display 2 as the most robust system. The measured occupied density of states of 2 with UV photoemission is in excellent agreement with theoretical DFT calculations.« less

Cell surface engineering of industrial microorganisms for biorefining applications.

PubMed

Tanaka, Tsutomu; Kondo, Akihiko

2015-11-15

In order to decrease carbon emissions and negative environmental impacts of various pollutants, biofuel/biochemical production should be promoted for replacing fossil-based industrial processes. Utilization of abundant lignocellulosic biomass as a feedstock has recently become an attractive option. In this review, we focus on recent efforts of cell surface display using industrial microorganisms such as Escherichia coli and yeast. Cell surface display is used primarily for endowing cellulolytic activity on the host cells, and enables direct fermentation to generate useful fuels and chemicals from lignocellulosic biomass. Cell surface display systems are systematically summarized, and the drawbacks/perspectives as well as successful application of surface display for industrial biotechnology are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of trimannoside-recognizing peptide sequences from a T7 phage display screen using a QCM device.

PubMed

Nishiyama, Kazusa; Takakusagi, Yoichi; Kusayanagi, Tomoe; Matsumoto, Yuki; Habu, Shiori; Kuramochi, Kouji; Sugawara, Fumio; Sakaguchi, Kengo; Takahashi, Hideyo; Natsugari, Hideaki; Kobayashi, Susumu

2009-01-01

Here, we report on the identification of trimannoside-recognizing peptide sequences from a T7 phage display screen using a quartz-crystal microbalance (QCM) device. A trimannoside derivative that can form a self-assembled monolayer (SAM) was synthesized and used for immobilization on the gold electrode surface of a QCM sensor chip. After six sets of one-cycle affinity selection, T7 phage particles displaying PSVGLFTH (8-mer) and SVGLGLGFSTVNCF (14-mer) were found to be enriched at a rate of 17/44, 9/44, respectively, suggesting that these peptides specifically recognize trimannoside. Binding checks using the respective single T7 phage and synthetic peptide also confirmed the specific binding of these sequences to the trimannoside-SAM. Subsequent analysis revealed that these sequences correspond to part of the primary amino acid sequence found in many mannose- or hexose-related proteins. Taken together, these results demonstrate the effectiveness of our T7 phage display environment for affinity selection of binding peptides. We anticipate this screening result will also be extremely useful in the development of inhibitors or drug delivery systems targeting polysaccharides as well as further investigations into the function of carbohydrates in vivo.

Construction of a cell-surface display system based on the N-terminal domain of ice nucleation protein and its application in identification of mycoplasma adhesion proteins.

PubMed

Bao, S; Yu, S; Guo, X; Zhang, F; Sun, Y; Tan, L; Duan, Y; Lu, F; Qiu, X; Ding, C

2015-07-01

To construct and demonstrate a surface display system that could be used to identify mycoplasma adhesion proteins. Using the N-terminal domain of InaZ (InaZN) as the anchoring motif and the enhanced green fluorescent protein (EGFP) as the reporter, the surface display system pET-InaZN-EGFP was constructed. Then, the mgc2 gene which encodes an adhesin and the holB gene which encodes DNA polymerase III subunit delta' (nonadhesin, negative control) of Mycoplasma gallisepticum were cloned into the pET-InaZN-EGFP respectively. The fusion proteins were expressed in Escherichia coli BL21 (DE3). The distribution of the fusion proteins in E. coli cells was determined using SDS-PAGE followed by Western blotting, based on cell fractionation. Escherichia coli cell surface display of the fusion protein was confirmed by immunofluorescence microscopy. The results indicated that the fusion proteins were not only anchored to the outer membrane fraction but also were successfully displayed on the surface of E. coli cells. Adhesion analysis of E. coli harbouring InaZN-EGFP-mgc2 to host cells showed that the MGC2-positive E. coli cells can effectively adhere to the surfaces of DF-1 cells. A surface display system using the InaZN as the anchoring motif and EGFP as the reporter was developed to identify putative adhesins of mycoplasma. Results indicated that adhesion by the cytadhesin-like protein MGC2 of mycoplasma can be reproduced using this surface display system. This is the first construction of surface display system which could be used to identify the adhesion proteins of mycoplasma. The method developed in this study can even be used to select and identify the adhesion proteins of other pathogens. © 2015 The Society for Applied Microbiology.

Peripheral B cells latently infected with Epstein–Barr virus display molecular hallmarks of classical antigen-selected memory B cells

PubMed Central

Souza, Tatyana A.; Stollar, B. David; Sullivan, John L.; Luzuriaga, Katherine; Thorley-Lawson, David A.

2005-01-01

Epstein–Barr virus (EBV) establishes a lifelong persistent infection within peripheral blood B cells with the surface phenotype of memory cells. To date there is no proof that these cells have the genotype of true germinal-center-derived memory B cells. It is critical to understand the relative contribution of viral mimicry versus antigen signaling to the production of these cells because EBV encodes proteins that can affect the surface phenotype of infected cells and provide both T cell help and B cell receptor signals in the absence of cognate antigen. To address these questions we have developed a technique to identify single EBV-infected cells in the peripheral blood and examine their expressed Ig genes. The genes were all isotype-switched and somatically mutated. Furthermore, the mutations do not cause stop codons and display the pattern expected for antigen-selected memory cells based on their frequency, type, and location within the Ig gene. We conclude that latently infected peripheral blood B cells display the molecular hallmarks of classical antigen-selected memory B cells. Therefore, EBV does not disrupt the normal processing of latently infected cells into memory, and deviations from normal B cell biology are not tolerated in the infected cells. This article provides definitive evidence that EBV in the peripheral blood persists in true memory B cells. PMID:16330748

Tactile feedback to the palm using arbitrarily shaped DEA

NASA Astrophysics Data System (ADS)

Mößinger, Holger; Haus, Henry; Kauer, Michaela; Schlaak, Helmut F.

2014-03-01

Tactile stimulation enhances user experience and efficiency in human machine interaction by providing information via another sensory channel to the human brain. DEA as tactile interfaces have been in the focus of research in recent years. Examples are (vibro-) tactile keyboards or Braille displays. These applications of DEA focus mainly on interfacing with the user's fingers or fingertips only - demonstrating the high spatial resolution achievable with DEA. Besides providing a high resolution, the flexibility of DEA also allows designing free form surfaces equipped with single actuators or actuator matrices which can be fitted to the surface of the human skin. The actuators can then be used to provide tactile stimuli to different areas of the body, not to the fingertips only. Utilizing and demonstrating this flexibility we designed a free form DEA pad shaped to fit into the inside of the human palm. This pad consists of four single actuators which can provide e.g. directional information such as left, right, up and down. To demonstrate the value of such free form actuators we manufactured a PC-mouse using 3d printing processes. The actuator pad is mounted on the back of the mouse, resting against the palm while operating it. Software on the PC allows control of the vibration patterns displayed by the actuators. This allows helping the user by raising attention to certain directions or by discriminating between different modes like "pick" or "manipulate". Results of first tests of the device show an improved user experience while operating the PC mouse.

Development of a Humanized Monoclonal Antibody with Therapeutic Potential against West Nile Virus

PubMed Central

Oliphant, Theodore; Engle, Michael; Nybakken, Grant E.; Doane, Chris; Johnson, Syd; Huang, Ling; Gorlatov, Sergey; Mehlhop, Erin; Marri, Anantha; Chung, Kyung Min; Ebel, Gregory D.; Kramer, Laura D.; Fremont, Daved H.; Diamond, Michael S.

2006-01-01

Neutralization of West Nile virus (WNV) in vivo correlates with the development of an antibody response against the viral envelope (E) protein. Using random mutagenesis and yeast surface display, we defined individual contact residues of 14 newly generated mAbs against domain III of the WNV E protein. MAbs that strongly neutralized WNV localized to a surface patch on the lateral face of domain III. Convalescent antibodies from human patients who had recovered from WNV infection also detected this epitope. One mAb, E16, neutralized 10 different strains in vitro, and demonstrated therapeutic efficacy in mice, even when administered as a single dose 5 d after infection. A humanized version of E16 was generated that retained antigen specificity, avidity, and neutralizing activity. In post-exposure therapeutic trials in mice, a single dose of humanized E16 protected mice against WNV-induced mortality, and thus, may be a viable treatment option against WNV infection in humans. PMID:15852016

Geometry and architecture of faults in a syn-rift normal fault array: The Nukhul half-graben, Suez rift, Egypt

NASA Astrophysics Data System (ADS)

Wilson, Paul; Gawthorpe, Rob L.; Hodgetts, David; Rarity, Franklin; Sharp, Ian R.

2009-08-01

The geometry and architecture of a well exposed syn-rift normal fault array in the Suez rift is examined. At pre-rift level, the Nukhul fault consists of a single zone of intense deformation up to 10 m wide, with a significant monocline in the hanging wall and much more limited folding in the footwall. At syn-rift level, the fault zone is characterised by a single discrete fault zone less than 2 m wide, with damage zone faults up to approximately 200 m into the hanging wall, and with no significant monocline developed. The evolution of the fault from a buried structure with associated fault-propagation folding, to a surface-breaking structure with associated surface faulting, has led to enhanced bedding-parallel slip at lower levels that is absent at higher levels. Strain is enhanced at breached relay ramps and bends inherited from pre-existing structures that were reactivated during rifting. Damage zone faults observed within the pre-rift show ramp-flat geometries associated with contrast in competency of the layers cut and commonly contain zones of scaly shale or clay smear. Damage zone faults within the syn-rift are commonly very straight, and may be discrete fault planes with no visible fault rock at the scale of observation, or contain relatively thin and simple zones of scaly shale or gouge. The geometric and architectural evolution of the fault array is interpreted to be the result of (i) the evolution from distributed trishear deformation during upward propagation of buried fault tips to surface faulting after faults breach the surface; (ii) differences in deformation response between lithified pre-rift units that display high competence contrasts during deformation, and unlithified syn-rift units that display low competence contrasts during deformation, and; (iii) the history of segmentation, growth and linkage of the faults that make up the fault array. This has important implications for fluid flow in fault zones.

Cell wall structure suitable for surface display of proteins in Saccharomyces cerevisiae.

PubMed

Matsuoka, Hiroyuki; Hashimoto, Kazuya; Saijo, Aki; Takada, Yuki; Kondo, Akihiko; Ueda, Mitsuyoshi; Ooshima, Hiroshi; Tachibana, Taro; Azuma, Masayuki

2014-02-01

A display system for adding new protein functions to the cell surfaces of microorganisms has been developed, and applications of the system to various fields have been proposed. With the aim of constructing a cell surface environment suitable for protein display in Saccharomyces cerevisiae, the cell surface structures of cell wall mutants were investigated. Four cell wall mutant strains were selected by analyses using a GFP display system via a GPI anchor. β-Glucosidase and endoglucanase II were displayed on the cell surface in the four mutants, and their activities were evaluated. mnn2 deletion strain exhibited the highest activity for both the enzymes. In particular, endoglucanase II activity using carboxymethylcellulose as a substrate in the mutant strain was 1.9-fold higher than that of the wild-type strain. In addition, the activity of endoglucanase II released from the mnn2 deletion strain by Zymolyase 20T treatment was higher than that from the wild-type strain. The results of green fluorescent protein (GFP) and endoglucanase displays suggest that the amounts of enzyme displayed on the cell surface were increased by the mnn2 deletion. The enzyme activity of the mnn2 deletion strain was compared with that of the wild-type strain. The relative value (mnn2 deletion mutant/wild-type strain) of endoglucanase II activity using carboxymethylcellulose as a substrate was higher than that of β-glucosidase activity using p-nitrophenyl-β-glucopyranoside as a substrate, suggesting that the cell surface environment of the mnn2 deletion strain facilitates the binding of high-molecular-weight substrates to the active sites of the displayed enzymes. Copyright © 2014 John Wiley & Sons, Ltd.

Electrochemical Glucose Biosensor Based on Glucose Oxidase Displayed on Yeast Surface.

PubMed

Wang, Hongwei; Lang, Qiaolin; Liang, Bo; Liu, Aihua

2015-01-01

The conventional enzyme-based biosensor requires chemical or physical immobilization of purified enzymes on electrode surface, which often results in loss of enzyme activity and/or fractions immobilized over time. It is also costly. A major advantage of yeast surface display is that it enables the direct utilization of whole cell catalysts with eukaryote-produced proteins being displayed on the cell surface, providing an economic alternative to traditional production of purified enzymes. Herein, we describe the details of the display of glucose oxidase (GOx) on yeast cell surface and its application in the development of electrochemical glucose sensor. In order to achieve a direct electrochemistry of GOx, the entire cell catalyst (yeast-GOx) was immobilized together with multiwalled carbon nanotubes on the electrode, which allowed sensitive and selective glucose detection.

Rotational Modulation and Activity Cycles at Rotational Extremes: 25 yrs of NURO Photometry for HII 1883

NASA Astrophysics Data System (ADS)

Milingo, Jackie; Saar, Steven; Marschall, Laurence

2018-01-01

We present a 25 yr compilation of V-band differential photometry for the Pleiades K dwarf HII 1883 (V660 Tau). HII 1883 has a rotational period of ~ 0.24 d and displays significant rotational modulation due to non-uniform surface brightness or "starspots". Preliminary work yields a cycle period of ~ 9 yrs and rotational shear (ΔP_rot/) considerably less than solar. HII 1883 is one of the fastest rotating single stars with a known cycle. With additional data available we compare newly determined P_cyc and ΔP_rot/ values with those of other stars, putting HII 1883 into the broader context of dynamo properties in single cool dwarfs.

Method for forming silicon on a glass substrate

DOEpatents

McCarthy, Anthony M.

1995-01-01

A method by which single-crystal silicon microelectronics may be fabricated on glass substrates at unconventionally low temperatures. This is achieved by fabricating a thin film of silicon on glass and subsequently forming the doped components by a short wavelength (excimer) laser doping procedure and conventional patterning techniques. This method may include introducing a heavily boron doped etch stop layer on a silicon wafer using an excimer laser, which permits good control of the etch stop layer removal process. This method additionally includes dramatically reducing the remaining surface roughness of the silicon thin films after etching in the fabrication of silicon on insulator wafers by scanning an excimer laser across the surface of the silicon thin film causing surface melting, whereby the surface tension of the melt causes smoothing of the surface during recrystallization. Applications for this method include those requiring a transparent or insulating substrate, such as display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard and high temperature electronics.

Method for forming silicon on a glass substrate

DOEpatents

McCarthy, A.M.

1995-03-07

A method by which single-crystal silicon microelectronics may be fabricated on glass substrates at unconventionally low temperatures. This is achieved by fabricating a thin film of silicon on glass and subsequently forming the doped components by a short wavelength (excimer) laser doping procedure and conventional patterning techniques. This method may include introducing a heavily boron doped etch stop layer on a silicon wafer using an excimer laser, which permits good control of the etch stop layer removal process. This method additionally includes dramatically reducing the remaining surface roughness of the silicon thin films after etching in the fabrication of silicon on insulator wafers by scanning an excimer laser across the surface of the silicon thin film causing surface melting, whereby the surface tension of the melt causes smoothing of the surface during recrystallization. Applications for this method include those requiring a transparent or insulating substrate, such as display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard and high temperature electronics. 15 figs.

Development of exosome surface display technology in living human cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stickney, Zachary, E-mail: zstickney@scu.edu; Losacco, Joseph, E-mail: jlosacco@scu.edu; McDevitt, Sophie, E-mail: smmcdevitt@scu.edu

Surface display technology is an emerging key player in presenting functional proteins for targeted drug delivery and therapy. Although a number of technologies exist, a desirable mammalian surface display system is lacking. Exosomes are extracellular vesicles that facilitate cell–cell communication and can be engineered as nano-shuttles for cell-specific delivery. In this study, we report the development of a novel exosome surface display technology by exploiting mammalian cell secreted nano-vesicles and their trans-membrane protein tetraspanins. By constructing a set of fluorescent reporters for both the inner and outer surface display on exosomes at two selected sites of tetraspanins, we demonstrated themore » successful exosomal display via gene transfection and monitoring fluorescence in vivo. We subsequently validated our system by demonstrating the expected intracellular partitioning of reporter protein into sub-cellular compartments and secretion of exosomes from human HEK293 cells. Lastly, we established the stable engineered cells to harness the ability of this robust system for continuous production, secretion, and uptake of displayed exosomes with minimal impact on human cell biology. In sum, our work paved the way for potential applications of exosome, including exosome tracking and imaging, targeted drug delivery, as well as exosome-mediated vaccine and therapy.« less

Integrated Display System for Low Visibility Landing and Surface Operations

NASA Technical Reports Server (NTRS)

Beskenis, Sharon Otero; Green, David F., Jr.; Hyer, Paul V.; Johnson, Edward J., Jr.

1998-01-01

This report summarizes the software products and system architectures developed by Lockheed Martin in support of the Low Visibility Landing and Surface Operations (LVLASO) program at NASA Langley Research Center. It presents an overview of the technical aspects, capabilities, and system integration issues associated with an integrated display system (IDS) that collects, processes and presents information to an aircraft flight crew during all phases of landing, roll-out, turn-off, inbound taxi, outbound taxi and takeoff. Communications hardware, drivers, and software provide continuous real-time data at varying rates and from many different sources to the display programs for presentation on a head-down display (HDD) and/or a head-up display (HUD). An electronic moving map of the airport surface is implemented on the HDD which includes the taxi route assigned by air traffic control, a text messaging system, and surface traffic and runway status information. Typical HUD symbology for navigation and control of the aircraft is augmented to provide aircraft deceleration guidance after touchdown to a pilot selected exit and taxi guidance along the route assigned by ATC. HUD displays include scene-linked symbolic runways, runway exits and taxiways that are conformal with the actual locations on the airport surface. Display formats, system architectures, and the various IDS programs are discussed.

Development and characterization of a camelid single-domain antibody directed to human CD22 biomarker.

PubMed

Faraji, Fatemeh; Tajik, Nader; Behdani, Mahdi; Shokrgozar, Mohammad Ali; Zarnani, Amir Hassan; Shahhosseini, Fatemeh; Habibi-Anbouhi, Mahdi

2018-03-15

CD22 is a B-cell-specific trans-membrane glycoprotein, which is found on the surface of the most B cells and modulates their function, survival, and apoptosis. Recently, targeting this cell surface biomarker in B-cell malignancies and disorders has attracted a lot of attention. The variable domain of camelid single-chain antibodies (VHH, nanobody) is a form of antibodies with novel properties including small size (15-17 kDa), thermal and chemical stability, high affinity and homology to human antibody sequences. In this study, a novel anti-CD22-specific VHH (Nb) has been developed and characterized by the screening of an immunized phage display library and its binding to CD22 + B cells is evaluated. Produced anti-CD22 VHH had a single protein band about 17 kDa of molecular size in Western blotting and its binding affinity was approximately 9 × 10 -9  M. Also, this product had high specificity and it was able to recognize the natural CD22 antigen in CD22+ cell lysate as well as on the cell surface (93%). This anti-CD22 VHH with both high affinity and specificity recognizes CD22 antigen well and can be used in diagnosis and treatment of B cell disorders and malignancies. © 2018 International Union of Biochemistry and Molecular Biology, Inc.

Survey Summary of AGATE Concepts Demonstration at Annual NATA Convention March 24-26, 1997. Volume 2; Original Survey Data

NASA Technical Reports Server (NTRS)

1997-01-01

An AGATE Concepts Demonstration was conducted at the Annual National Air Transportation Association (NATA) Convention in 1997. Following, a 5-minute introductory briefing, an interactive simulation of a single-pilot, single-engine aircraft was conducted. The participant was able to take off, fly a brief enroute segment, fly a Global Positioning System (GPS) approach and landing, and repeat the approach and landing segment. The participant was provided an advanced 'highway-in-the-sky' presentation on both a simulated head-up display and on a large LCD head-down display to follow throughout the flight. A single-lever power control and display concept was also provided for control of the engine throughout the flight. A second head-down, multifunction display in the instrument panel provided a moving map display for navigation purposes and monitoring of the status of the aircraft's systems.

Method of forming crystalline silicon devices on glass

DOEpatents

McCarthy, A.M.

1995-03-21

A method is disclosed for fabricating single-crystal silicon microelectronic components on a silicon substrate and transferring same to a glass substrate. This is achieved by utilizing conventional silicon processing techniques for fabricating components of electronic circuits and devices on bulk silicon, wherein a bulk silicon surface is prepared with epitaxial layers prior to the conventional processing. The silicon substrate is bonded to a glass substrate and the bulk silicon is removed leaving the components intact on the glass substrate surface. Subsequent standard processing completes the device and circuit manufacturing. This invention is useful in applications requiring a transparent or insulating substrate, particularly for display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard electronics, and high temperature electronics. 7 figures.

Selection of full-length IgGs by tandem display on filamentous phage particles and Escherichia coli fluorescence-activated cell sorting screening.

PubMed

Mazor, Yariv; Van Blarcom, Thomas; Carroll, Sean; Georgiou, George

2010-05-01

Phage display of antibody libraries is a powerful tool for antibody discovery and evolution. Recombinant antibodies have been displayed on phage particles as scFvs or Fabs, and more recently as bivalent F(ab')(2). We recently developed a technology (E-clonal) for screening of combinatorial IgG libraries using bacterial periplasmic display and selection by fluorescence-activated cell sorting (FACS) [Mazor Y et al. (2007) Nat Biotechnol 25, 563-565]. Although, as a single-cell analysis technique, FACS is very powerful, especially for the isolation of high-affinity binders, even with state of the art instrumentation the screening of libraries with diversity > 10(8) is technically challenging. We report here a system that takes advantage of display of full-length IgGs on filamentous phage particles as a prescreening step to reduce library size and enable subsequent rounds of FACS screening in Escherichia coli. For the establishment of an IgG phage display system, we utilized phagemid-encoded IgG with the fUSE5-ZZ phage as a helper phage. These phage particles display the Fc-binding ZZ protein on all copies of the phage p3 coat protein, and are exploited as both helper phages and anchoring surfaces for the soluble IgG. We demonstrate that tandem phage selection followed by FACS allows the selection of a highly diversified profile of binders from antibody libraries without undersampling, and at the same time capitalizes on the advantages of FACS for real-time monitoring and optimization of the screening process.

Engineering Novel and Improved Biocatalysts by Cell Surface Display

PubMed Central

Smith, Mason R.; Khera, Eshita; Wen, Fei

2017-01-01

Biocatalysts, especially enzymes, have the ability to catalyze reactions with high product selectivity, utilize a broad range of substrates, and maintain activity at low temperature and pressure. Therefore, they represent a renewable, environmentally friendly alternative to conventional catalysts. Most current industrial-scale chemical production processes using biocatalysts employ soluble enzymes or whole cells expressing intracellular enzymes. Cell surface display systems differ by presenting heterologous enzymes extracellularly, overcoming some of the limitations associated with enzyme purification and substrate transport. Additionally, coupled with directed evolution, cell surface display is a powerful platform for engineering enzymes with enhanced properties. In this review, we will introduce the molecular and cellular principles of cell surface display and discuss how it has been applied to engineer enzymes with improved properties as well as to develop surface-engineered microbes as whole-cell biocatalysts. PMID:29056821

A novel emissive projection display (EPD) on transparent phosphor screen

NASA Astrophysics Data System (ADS)

Cheng, Botao; Sun, Leonard; Yu, Ge; Sun, Ted X.

2017-03-01

A new paradigm of digital projection is on the horizon, based on innovative emissive screen that are made fully transparent. It can be readily applied and convert any surface to a high image quality emissive digital display, without affecting the surface appearance. For example, it can convert any glass window or windshield to completely see-through display, with unlimited field of view and viewing angles. It also enables a scalable and economic projection display on a pitch-black emissive screen with black level and image contrast that rivals other emissive displays such as plasma display or OLED.

A single molecule perspective on the functional diversity of in vitro evolved β-glucuronidase.

PubMed

Liebherr, Raphaela B; Renner, Max; Gorris, Hans H

2014-04-23

The mechanisms that drive the evolution of new enzyme activity have been investigated by comparing the kinetics of wild-type and in vitro evolved β-glucuronidase (GUS) at the single molecule level. Several hundred single GUS molecules were separated in large arrays of 62,500 ultrasmall reaction chambers etched into the surface of a fused silica slide to observe their individual substrate turnover rates in parallel by fluorescence microscopy. Individual GUS molecules feature long-lived but divergent activity states, and their mean activity is consistent with classic Michaelis-Menten kinetics. The large number of single molecule substrate turnover rates is representative of the activity distribution within an entire enzyme population. Partially evolved GUS displays a much broader activity distribution among individual enzyme molecules than wild-type GUS. The broader activity distribution indicates a functional division of work between individual molecules in a population of partially evolved enzymes that-as so-called generalists-are characterized by their promiscuous activity with many different substrates.

Non-binary Colour Modulation for Display Device Based on Phase Change Materials.

PubMed

Ji, Hong-Kai; Tong, Hao; Qian, Hang; Hui, Ya-Juan; Liu, Nian; Yan, Peng; Miao, Xiang-Shui

2016-12-19

A reflective-type display device based on phase change materials is attractive because of its ultrafast response time and high resolution compared with a conventional display device. This paper proposes and demonstrates a unique display device in which multicolour changing can be achieved on a single device by the selective crystallization of double layer phase change materials. The optical contrast is optimized by the availability of a variety of film thicknesses of two phase change layers. The device exhibits a low sensitivity to the angle of incidence, which is important for display and colour consistency. The non-binary colour rendering on a single device is demonstrated for the first time using optical excitation. The device shows the potential for ultrafast display applications.

Humoral immune responses against gonadotropin releasing hormone elicited by immunization with phage-peptide constructs obtained via phage display.

PubMed

Samoylov, Alexandre; Cochran, Anna; Schemera, Bettina; Kutzler, Michelle; Donovan, Caitlin; Petrenko, Valery; Bartol, Frank; Samoylova, Tatiana

2015-12-20

Phage display is based on genetic engineering of phage coat proteins resulting in fusion peptides displayed on the surface of phage particles. The technology is widely used for generation of phages with novel characteristics for numerous applications in biomedicine and far beyond. The focus of this study was on development of phage-peptide constructs that stimulate production of antibodies against gonadotropin releasing hormone (GnRH). Phage-peptide constructs that elicit production of neutralizing GnRH antibodies can be used for anti-fertility and anti-cancer applications. Phage-GnRH constructs were generated via selection from a phage display library using several types of GnRH antibodies as selection targets. Such phage constructs were characterized for sequence similarities to GnRH peptide and frequency of their occurrence in the selection rounds. Five of the constructs with suitable characteristics were tested in mice as a single dose 5×10(11) virions (vir) vaccine and were found to be able to stimulate production of GnRH-specific antibodies, but not to suppress testosterone (indirect indicator of GnRH antibody neutralizing properties). Next, one of the constructs was tested at a higher dose of 2×10(12) vir per mouse in combination with a poly(lactide-co-glycolide) (PLGA)-based adjuvant. This resulted in multifold increase in GnRH antibody production and significant reduction of serum testosterone, indicating that antibodies produced in response to the phage-GnRH immunization possess neutralizing properties. To achieve optimal immune responses for desired applications, phage-GnRH constructs can be modified with respect to flanking sequences of GnRH-like peptides displayed on phage. Anticipated therapeutic effects also might be attained using optimized phage doses, a combination of several constructs in a single treatment, or application of adjuvants and advanced phage delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Postdoctoral Fellow | Center for Cancer Research

Cancer.gov

Dr. Mitchell Ho’s laboratory at the National Cancer Institute in Bethesda, Maryland, USA has an open postdoctoral position. We seek a highly motivated and creative individual to participate in a collaborative research project that involves the targeting of tumor-specific cell surface glypicans (e.g. GPC2, GPC3) using human T-cells engineered to express chimeric antigen receptors (CARs). The laboratory focuses on the understanding of the role of glypicans in cancer signaling, in particular Wnt signaling, and the development of CAR T cell therapies for treating liver cancer, neuroblastoma and other cancers. The successful candidate would be involved in isolation of human antibodies and camel or shark single domain antibodies using phage display, yeast display and mammalian cell display technologies, and production of CAR T cells, and preclinical testing of the CAR T cells using mouse tumor models. A recent paper related to the background of this project has been published in PNAS (https://www.ncbi.nlm.nih.gov/pubmed/28739923). Detailed information about Dr. Ho's research and publications can be accessed at: https://ccr.cancer.gov/mitchell-ho

Figure and Ground in the Visual Cortex: V2 Combines Stereoscopic Cues with Gestalt Rules

PubMed Central

Qiu, Fangtu T.; von der Heydt, Rüdiger

2006-01-01

Figure-ground organization is a process by which the visual system identifies some image regions as foreground and others as background, inferring three-dimensional (3D) layout from 2D displays. A recent study reported that edge responses of neurons in area V2 are selective for side-of-figure, suggesting that figure-ground organization is encoded in the contour signals (border-ownership coding). Here we show that area V2 combines two strategies of computation, one that exploits binocular stereoscopic information for the definition of local depth order, and another that exploits the global configuration of contours (gestalt factors). These are combined in single neurons so that the ‘near’ side of the preferred 3D edge generally coincides with the preferred side-of-figure in 2D displays. Thus, area V2 represents the borders of 2D figures as edges of surfaces, as if the figures were objects in 3D space. Even in 3D displays gestalt factors influence the responses and can enhance or null the stereoscopic depth information. PMID:15996555

Figure and ground in the visual cortex: v2 combines stereoscopic cues with gestalt rules.

PubMed

Qiu, Fangtu T; von der Heydt, Rüdiger

2005-07-07

Figure-ground organization is a process by which the visual system identifies some image regions as foreground and others as background, inferring 3D layout from 2D displays. A recent study reported that edge responses of neurons in area V2 are selective for side-of-figure, suggesting that figure-ground organization is encoded in the contour signals (border ownership coding). Here, we show that area V2 combines two strategies of computation, one that exploits binocular stereoscopic information for the definition of local depth order, and another that exploits the global configuration of contours (Gestalt factors). These are combined in single neurons so that the "near" side of the preferred 3D edge generally coincides with the preferred side-of-figure in 2D displays. Thus, area V2 represents the borders of 2D figures as edges of surfaces, as if the figures were objects in 3D space. Even in 3D displays, Gestalt factors influence the responses and can enhance or null the stereoscopic depth information.

A phage display vector optimized for the generation of human antibody combinatorial libraries and the molecular cloning of monoclonal antibody fragments.

PubMed

Solforosi, Laura; Mancini, Nicasio; Canducci, Filippo; Clementi, Nicola; Sautto, Giuseppe Andrea; Diotti, Roberta Antonia; Clementi, Massimo; Burioni, Roberto

2012-07-01

A novel phagemid vector, named pCM, was optimized for the cloning and display of antibody fragment (Fab) libraries on the surface of filamentous phage. This vector contains two long DNA "stuffer" fragments for easier differentiation of the correctly cut forms of the vector. Moreover, in pCM the fragment at the heavy-chain cloning site contains an acid phosphatase-encoding gene allowing an easy distinction of the Escherichia coli cells containing the unmodified form of the phagemid versus the heavy-chain fragment coding cDNA. In pCM transcription of heavy-chain Fd/gene III and light chain is driven by a single lacZ promoter. The light chain is directed to the periplasm by the ompA signal peptide, whereas the heavy-chain Fd/coat protein III is trafficked by the pelB signal peptide. The phagemid pCM was used to generate a human combinatorial phage display antibody library that allowed the selection of a monoclonal Fab fragment antibody directed against the nucleoprotein (NP) of Influenza A virus.

Reorganization of lipid domain distribution in giant unilamellar vesicles upon immobilization with different membrane tethers.

PubMed

Sarmento, M J; Prieto, M; Fernandes, Fábio

2012-11-01

Characterization of phase coexistence in biologically relevant lipid mixtures is often carried out through confocal microscopy of giant unilamellar lipid vesicles (GUVs), loaded with fluorescent membrane probes. This last analysis is generally limited to the vesicle hemisphere further away from the coverslip, in order to avoid artifacts induced by the interaction with the solid surface, and immobilization of vesicles is in many cases required in order to carry out intensity, lifetime or single-molecule based microscopy. This is generally achieved through the use of membrane tethers adhering to a coverslip surface. Here, we aimed to determine whether GUV immobilization through membrane tethers induces changes in lipid domain distribution within liposomes displaying coexistence of lipid lamellar phases. Confocal imaging and a Förster resonance energy transfer (FRET) methodology showed that biotinylated phospholipids present significantly different membrane phase partition behavior upon protein binding, depending on the presence or absence of a linker between the lipid headgroup and the biotinyl moiety. Membrane phases enriched in a membrane tether displayed in some cases a dramatically increased affinity for the immobilization surface, effectively driving sorting of lipid domains to the adherent membrane area, and in some cases complete sequestering of a lipid phase to the interaction surface was observed. On the light of these results, we conclude that tethering of lipid membranes to protein surfaces has the potential to drastically reorganize the distribution of lipid domains, and this reorganization is solely dictated by the partition properties of the protein-tether complex. Copyright © 2012 Elsevier B.V. All rights reserved.

Production of a Recombinant Antibody Specific for i Blood Group Antigen, a Mesenchymal Stem Cell Marker

PubMed Central

Suila, Heli; Tiitinen, Sari; Natunen, Suvi; Laukkanen, Marja-Leena; Kotovuori, Annika; Reinman, Mirka; Satomaa, Tero; Alfthan, Kaija; Laitinen, Saara; Takkinen, Kristiina; Räbinä, Jarkko; Valmu, Leena

2013-01-01

Abstract Multipotent mesenchymal stem/stromal cells (MSCs) offer great promise for future regenerative and anti-inflammatory therapies. Panels of functional and phenotypical markers are currently used in characterization of different therapeutic stem cell populations from various sources. The i antigen (linear poly-N-acetyllactosamine) from the Ii blood group system has been suggested as a marker for MSCs derived from umbilical cord blood (UCB). However, there are currently no commercially available antibodies recognizing the i antigen. In the present study, we describe the use of antibody phage display technology to produce recombinant antibodies recognizing a structure from the surface of mesenchymal stem cells. We constructed IgM phage display libraries from the lymphocytes of a donor with an elevated serum anti-i titer. Antibody phage display technology is not dependent on immunization and thus allows the generation of antibodies against poorly immunogenic molecules, such as carbohydrates. Agglutination assays utilizing i antigen–positive red blood cells (RBCs) from UCB revealed six promising single-chain variable fragment (scFv) antibodies, three of which recognized epitopes from the surface of UCB-MSCs in flow cytometric assays. The amino acid sequence of the VH gene segment of B12.2 scFv was highly similar to the VH4.21 gene segment required to encode anti-i specificities. Further characterization of binding properties revealed that the binding of B12.2 hyperphage was inhibited by soluble linear lactosamine oligosaccharide. Based on these findings, we suggest that the B12.2 scFv we have generated is a prominent anti-i antibody that recognizes i antigen on the surface of both UCB-MSCs and RBCs. This binder can thus be utilized in UCB-MSC detection and isolation as well as in blood group serology. PMID:24083089

Isolation and characterization of anti ROR1 single chain fragment variable antibodies using phage display technique.

PubMed

Aghebati-Maleki, Leili; Younesi, Vahid; Jadidi-Niaragh, Farhad; Baradaran, Behzad; Majidi, Jafar; Yousefi, Mehdi

2017-01-01

Receptor tyrosine kinase-like orphan receptor (ROR1) belongs to one of the families of receptor tyrosine kinases (RTKs). RTKs are involved in the various physiologic cellular functions including proliferation, migration, survival, signaling and differentiation. Several RTKs are deregulated in various cancers implying the targeting potential of these molecules in cancer therapy. ROR1 has recently been shown to be expressed in various types of cancer cells but not in normal adult cells. Hence a molecular inhibitor of extracellular domain of ROR1 that inhibits ROR1-cell surface interaction is of great therapeutic importance. In an attempt to develop molecular inhibitors of ROR1, we screened single chain variable fragment (scFv) phage display libraries, Tomlinson I + J, against one specific synthetic oligopeptide from extracellular domain of ROR1 and selected scFvs were characterized using various immunological techniques. Several ROR1 specific scFvs were selected following five rounds of panning procedure. The scFvs showed specific binding to ROR1 using immunological techniques. Our results demonstrate successful isolation and characterization of specific ROR1 scFvs that may have great therapeutic potential in cancer immunotherapy.

Fine structure of the retinal pigment epithelium of the great horned owl (Bubo virginianus).

PubMed

Braekevelt, C R; Thorlakson, I J

1993-01-01

The fine structure of the retinal epithelium (RPE), choriocapillaries and Bruch's membrane (complexus basalis) has been studied by light and electron microscopy in the great horned owl (Bubo virginianus). The RPE consists of a single layer of cuboidal cells joined laterally in the mid to basal region by a series of tight junctions forming part of the blood-ocular barrier. Basally (sclerally) the epithelial cells show numerous deep infoldings while apically (vitreally) a wealth of microvillar processes interdigitate with the photoreceptor cells. Internally the RPE cells display a large vesicular nucleus, plentiful smooth endoplasmic reticulum (SER) and polysomes with only small scattered profiles of rough endoplasmic reticulum (RER). Numerous pleomorphic mitochondria are basally located. In the light-adapted state the melanosomes are located almost exclusively within the apical processes indicating retinomotor movements. Myeloid bodies are numerous and often show ribosomes on their outer surface. Bruch's membrane is typical of avian species in that it is pentalaminate and the lamina densa is displaced towards the choriocapillaris. The choriocapillaris itself is but minimally fenestrated facing Bruch's membrane. Most fenestrations present show a single layered diaphragm while others display a double-layered diaphragm.

Decolorization of textile dye RB19 using volcanic rock matrix immobilized Bacillus thuringiensis cells with surface displayed laccase.

PubMed

Wan, Juan; Sun, Xiaowen; Liu, Cheng; Tang, Mengjun; Li, Lin; Ni, Hong

2017-06-01

A triplicate volcanic rock matrix-Bacillus thuringiensis-laccase WlacD (VRMs-Bt-WlacD) dye decolorization system was developed. WlacD was displayed on the B. thuringiensis MB174 cell surface to prepare a whole-cell laccase biocatalyst by using two repeat N-terminal domains of autolysin Mbg (Mbgn) 2 as the anchoring motif. Immunofluorescence microscopic assays confirmed that the fusion protein (Mbgn) 2 -WlacD was anchored on the surface of the recombinant B. thuringiensis MB174. After optimization by a single factor test, L 9 (3 4 )-orthogonal test, Plackett-Burman test, steepest ascent method, and Box-Behnken response surface methodology, the whole-cell specific laccase activity of B. thuringiensis MB174 was improved to 555.2 U L -1 , which was 2.25 times than that of the primary culture condition. Optimized B. thuringiensis MB174 cells were further adsorbed by VRMs to prepare VRMs-Bt-WlacD, an immobilized whole-cell laccase biocatalyst. Decolorization capacity of as-prepared VRMs-Bt-WlacD toward an initial concentration of 500 mg L -1 of an textile dye reactive blue 19 (RB19) aqueous solution reached 72.36% at a solid-to-liquid ratio of 10 g-100 mL. Repeated decolorization-activation operations showed the high decolorization capacity of VRMs-Bt-WlacD and have the potential for large-scale or continuous operations.

Blur and the perception of depth at occlusions.

PubMed

Zannoli, Marina; Love, Gordon D; Narain, Rahul; Banks, Martin S

2016-01-01

The depth ordering of two surfaces, one occluding the other, can in principle be determined from the correlation between the occlusion border's blur and the blur of the two surfaces. If the border is blurred, the blurrier surface is nearer; if the border is sharp, the sharper surface is nearer. Previous research has found that observers do not use this informative cue. We reexamined this finding. Using a multiplane display, we confirmed the previous finding: Our observers did not accurately judge depth order when the blur was rendered and the stimulus presented on one plane. We then presented the same simulated scenes on multiple planes, each at a different focal distance, so the blur was created by the optics of the eye. Performance was now much better, which shows that depth order can be reliably determined from blur information but only when the optical effects are similar to those in natural viewing. We asked what the critical differences were in the single- and multiplane cases. We found that chromatic aberration provides useful information but accommodative microfluctuations do not. In addition, we examined how image formation is affected by occlusions and observed some interesting phenomena that allow the eye to see around and through occluding objects and may allow observers to estimate depth in da Vinci stereopsis, where one eye's view is blocked. Finally, we evaluated how accurately different rendering and displaying techniques reproduce the retinal images that occur in real occlusions. We discuss implications for computer graphics.

Display of a β-mannanase and a chitosanase on the cell surface of Lactobacillus plantarum towards the development of whole-cell biocatalysts.

PubMed

Nguyen, Hoang-Minh; Mathiesen, Geir; Stelzer, Elena Maria; Pham, Mai Lan; Kuczkowska, Katarzyna; Mackenzie, Alasdair; Agger, Jane W; Eijsink, Vincent G H; Yamabhai, Montarop; Peterbauer, Clemens K; Haltrich, Dietmar; Nguyen, Thu-Ha

2016-10-04

Lactobacillus plantarum is considered as a potential cell factory because of its GRAS (generally recognized as safe) status and long history of use in food applications. Its possible applications include in situ delivery of proteins to a host, based on its ability to persist at mucosal surfaces of the human intestine, and the production of food-related enzymes. By displaying different enzymes on the surface of L. plantarum cells these could be used as whole-cell biocatalysts for the production of oligosaccharides. In this present study, we aimed to express and display a mannanase and a chitosanase on the cell surface of L. plantarum. ManB, a mannanase from Bacillus licheniformis DSM13, and CsnA, a chitosanase from Bacillus subtilis ATCC 23857 were fused to different anchoring motifs of L. plantarum for covalent attachment to the cell surface, either via an N-terminal lipoprotein anchor (Lp_1261) or a C-terminal cell wall anchor (Lp_2578), and the resulting fusion proteins were expressed in L. plantarum WCFS1. The localization of the recombinant proteins on the bacterial cell surface was confirmed by flow cytometry and immunofluorescence microscopy. The highest mannanase and chitosanase activities obtained for displaying L. plantarum cells were 890 U and 1360 U g dry cell weight, respectively. In reactions with chitosan and galactomannans, L. plantarum CsnA- and ManB-displaying cells produced chito- and manno-oligosaccharides, respectively, as analyzed by high performance anion exchange chromatography (HPAEC) and mass spectrometry (MS). Surface-displayed ManB is able to break down galactomannan (LBG) into smaller manno-oligosaccharides, which can support growth of L. plantarum. This study shows that mannanolytic and chitinolytic enzymes can be anchored to the cell surface of L. plantarum in active forms. L. plantarum chitosanase- and mannanase-displaying cells should be of interest for the production of potentially 'prebiotic' oligosaccharides. This approach, with the enzyme of interest being displayed on the cell surface of a food-grade organism, may also be applied in production processes relevant for food industry.

Expression and display of UreA of Helicobacter acinonychis on the surface of Bacillus subtilis spores.

PubMed

Hinc, Krzysztof; Isticato, Rachele; Dembek, Marcin; Karczewska, Joanna; Iwanicki, Adam; Peszyńska-Sularz, Grazyna; De Felice, Maurilio; Obuchowski, Michał; Ricca, Ezio

2010-01-18

The bacterial endospore (spore) has recently been proposed as a new surface display system. Antigens and enzymes have been successfully exposed on the surface layers of the Bacillus subtilis spore, but only in a few cases the efficiency of expression and the effective surface display and have been determined. We used this heterologous expression system to produce the A subunit of the urease of the animal pathogen Helicobater acinonychis. Ureases are multi-subunit enzymes with a central role in the virulence of various bacterial pathogens and necessary for colonization of the gastric mucosa by the human pathogen H. pylori. The urease subunit UreA has been recognized as a major antigen, able to induce high levels of protection against challenge infections. We expressed UreA from H. acinonychis on the B. subtilis spore coat by using three different spore coat proteins as carriers and compared the efficiency of surface expression and surface display obtained with the three carriers. A combination of western-, dot-blot and immunofluorescence microscopy allowed us to conclude that, when fused to CotB, UreA is displayed on the spore surface (ca. 1 x 10(3) recombinant molecules per spore), whereas when fused to CotC, although most efficiently expressed (7-15 x 10(3) recombinant molecules per spore) and located in the coat layer, it is not displayed on the surface. Experiments with CotG gave results similar to those with CotC, but the CotG-UreA recombinant protein appeared to be partially processed. UreA was efficiently expressed on the spore coat of B. subtilis when fused to CotB, CotC or CotG. Of these three coat proteins CotC allows the highest efficiency of expression, whereas CotB is the most appropriate for the display of heterologous proteins on the spore surface.

Differential Processing of Isolated Object and Multi-item Pop-Out Displays in LIP and PFC.

PubMed

Meyers, Ethan M; Liang, Andy; Katsuki, Fumi; Constantinidis, Christos

2017-10-11

Objects that are highly distinct from their surroundings appear to visually "pop-out." This effect is present for displays in which: (1) a single cue object is shown on a blank background, and (2) a single cue object is highly distinct from surrounding objects; it is generally assumed that these 2 display types are processed in the same way. To directly examine this, we applied a decoding analysis to neural activity recorded from the lateral intraparietal (LIP) area and the dorsolateral prefrontal cortex (dlPFC). Our analyses showed that for the single-object displays, cue location information appeared earlier in LIP than in dlPFC. However, for the display with distractors, location information was substantially delayed in both brain regions, and information first appeared in dlPFC. Additionally, we see that pattern of neural activity is similar for both types of displays and across different color transformations of the stimuli, indicating that location information is being coded in the same way regardless of display type. These results lead us to hypothesize that 2 different pathways are involved processing these 2 types of pop-out displays. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Tangible display systems: direct interfaces for computer-based studies of surface appearance

NASA Astrophysics Data System (ADS)

Darling, Benjamin A.; Ferwerda, James A.

2010-02-01

When evaluating the surface appearance of real objects, observers engage in complex behaviors involving active manipulation and dynamic viewpoint changes that allow them to observe the changing patterns of surface reflections. We are developing a class of tangible display systems to provide these natural modes of interaction in computer-based studies of material perception. A first-generation tangible display was created from an off-the-shelf laptop computer containing an accelerometer and webcam as standard components. Using these devices, custom software estimated the orientation of the display and the user's viewing position. This information was integrated with a 3D rendering module so that rotating the display or moving in front of the screen would produce realistic changes in the appearance of virtual objects. In this paper, we consider the design of a second-generation system to improve the fidelity of the virtual surfaces rendered to the screen. With a high-quality display screen and enhanced tracking and rendering capabilities, a secondgeneration system will be better able to support a range of appearance perception applications.

Surface-confined Ullmann coupling of thiophene substituted porphyrins

NASA Astrophysics Data System (ADS)

Beggan, J. P.; Boyle, N. M.; Pryce, M. T.; Cafolla, A. A.

2015-09-01

The covalent coupling of (5,10,15,20-tetrabromothien-2-ylporphyrinato)zinc(II) (TBrThP) molecules on the Ag(111) surface has been investigated under ultra-high-vacuum conditions, using scanning tunnelling microscopy and x-ray photoelectron spectroscopy. The findings provide atomic-level insight into surface-confined Ullmann coupling of thiophene substituted porphyrins, analyzing the progression of organometallic intermediate to final coupled state. Adsorption of the TBrThP molecules on the Ag(111) surface at room temperature is found to result in the reductive dehalogenation of the bromothienyl substituents and the subsequent formation of single strand and crosslinked coordination networks. The coordinated substrate atoms bridge the proximal thienyl groups of the organometallic intermediate, while the cleaved bromine atoms are bound on the adjacent Ag(111) surface. The intermediate complex displays a thermal lability at ˜423 K that results in the dissociation of the proximal thienyl groups with the concomitant loss of the surface bound bromine. At the thermally induced dissociation of the intermediate complex the resultant thienylporphyrin derivatives covalently couple, leading to the formation of a polymeric network of thiophene linked and meso-meso fused porphyrins.

Optical characterization of display screens by speckle-contrast measurements

NASA Astrophysics Data System (ADS)

Pozo, Antonio M.; Castro, José J.; Rubiño, Manuel

2012-10-01

In recent years, the flat-panel display (FPD) technology has undergone great development. Currently, FPDs are present in many devices. A significant element in FPD manufacturing is the display front surface. Manufacturers sell FPDs with different types of front surface which can be matte (also called anti-glare) or glossy screens. Users who prefer glossy screens consider images shown in these types of displays to have more vivid colours compared with matte-screen displays. However, external light sources may cause unpleasant reflections on the glossy screens. These reflections can be reduced by a matte treatment in the front surface of FPDs. In this work, we present a method to characterize the front surface of FPDs using laser speckle patterns. We characterized three FPDs: a Samsung XL2370 LCD monitor of 23" with matte screen, a Toshiba Satellite A100 laptop of 15.4" with glossy screen, and a Papyre electronic book reader. The results show great differences in speckle contrast values for the three screens characterized and, therefore, this work shows the feasibility of this method for characterizing and comparing FPDs which have different types of front surfaces.

On the evaluation of air mass factors for atmospheric near-ultraviolet and visible absorption spectroscopy

NASA Technical Reports Server (NTRS)

Perliski, Lori M.; Solomon, Susan

1993-01-01

The interpretation of UV-visible twilight absorption measurements of atmospheric chemical constituents is dependent on how well the optical path, or air mass factor, of light collected by the spectrometer is understood. A simple single scattering model and a Monte Carlo radiative transfer scheme have been developed to study the effects of multiple scattering, aerosol scattering, surface albedo and refraction on air mass factors for scattered light observations. At fairly short visible wavelengths (less than about 450 nm), stratospheric air mass factors are found to be relatively insensitive to multiple scattering, surface albedo and refraction, as well as aerosol scattering by background aerosols. Longer wavelengths display greater sensitivity to refraction and aerosol scattering. Tropospheric air mass factors are found to be highly dependent on aerosol scattering, surface albedo and, at long visible wavelengths (about 650 nm), refraction. Absorption measurements of NO2 and O4 are shown to support these conclusions.

Flight Deck Display Technologies for 4DT and Surface Equivalent Visual Operations

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III; Jones, Denis R.; Shelton, Kevin J.; Arthur, Jarvis J., III; Bailey, Randall E.; Allamandola, Angela S.; Foyle, David C.; Hooey, Becky L.

2009-01-01

NASA research is focused on flight deck display technologies that may significantly enhance situation awareness, enable new operating concepts, and reduce the potential for incidents/accidents for terminal area and surface operations. The display technologies include surface map, head-up, and head-worn displays; 4DT guidance algorithms; synthetic and enhanced vision technologies; and terminal maneuvering area traffic conflict detection and alerting systems. This work is critical to ensure that the flight deck interface technologies and the role of the human participants can support the full realization of the Next Generation Air Transportation System (NextGen) and its novel operating concepts.

Design of a single projector multiview 3D display system

NASA Astrophysics Data System (ADS)

Geng, Jason

2014-03-01

Multiview three-dimensional (3D) display is able to provide horizontal parallax to viewers with high-resolution and fullcolor images being presented to each view. Most multiview 3D display systems are designed and implemented using multiple projectors, each generating images for one view. Although this multi-projector design strategy is conceptually straightforward, implementation of such multi-projector design often leads to a very expensive system and complicated calibration procedures. Even for a multiview system with a moderate number of projectors (e.g., 32 or 64 projectors), the cost of a multi-projector 3D display system may become prohibitive due to the cost and complexity of integrating multiple projectors. In this article, we describe an optical design technique for a class of multiview 3D display systems that use only a single projector. In this single projector multiview (SPM) system design, multiple views for the 3D display are generated in a time-multiplex fashion by the single high speed projector with specially designed optical components, a scanning mirror, and a reflective mirror array. Images of all views are generated sequentially and projected via the specially design optical system from different viewing directions towards a 3D display screen. Therefore, the single projector is able to generate equivalent number of multiview images from multiple viewing directions, thus fulfilling the tasks of multiple projectors. An obvious advantage of the proposed SPM technique is the significant reduction of cost, size, and complexity, especially when the number of views is high. The SPM strategy also alleviates the time-consuming procedures for multi-projector calibration. The design method is flexible and scalable and can accommodate systems with different number of views.

Awareness and Detection of Traffic and Obstacles Using Synthetic and Enhanced Vision Systems

NASA Technical Reports Server (NTRS)

Bailey, Randall E.

2012-01-01

Research literature are reviewed and summarized to evaluate the awareness and detection of traffic and obstacles when using Synthetic Vision Systems (SVS) and Enhanced Vision Systems (EVS). The study identifies the critical issues influencing the time required, accuracy, and pilot workload associated with recognizing and reacting to potential collisions or conflicts with other aircraft, vehicles and obstructions during approach, landing, and surface operations. This work considers the effect of head-down display and head-up display implementations of SVS and EVS as well as the influence of single and dual pilot operations. The influences and strategies of adding traffic information and cockpit alerting with SVS and EVS were also included. Based on this review, a knowledge gap assessment was made with recommendations for ground and flight testing to fill these gaps and hence, promote the safe and effective implementation of SVS/EVS technologies for the Next Generation Air Transportation System

Amyloidogenic Regions and Interaction Surfaces Overlap in Globular Proteins Related to Conformational Diseases

PubMed Central

Castillo, Virginia; Ventura, Salvador

2009-01-01

Protein aggregation underlies a wide range of human disorders. The polypeptides involved in these pathologies might be intrinsically unstructured or display a defined 3D-structure. Little is known about how globular proteins aggregate into toxic assemblies under physiological conditions, where they display an initially folded conformation. Protein aggregation is, however, always initiated by the establishment of anomalous protein-protein interactions. Therefore, in the present work, we have explored the extent to which protein interaction surfaces and aggregation-prone regions overlap in globular proteins associated with conformational diseases. Computational analysis of the native complexes formed by these proteins shows that aggregation-prone regions do frequently overlap with protein interfaces. The spatial coincidence of interaction sites and aggregating regions suggests that the formation of functional complexes and the aggregation of their individual subunits might compete in the cell. Accordingly, single mutations affecting complex interface or stability usually result in the formation of toxic aggregates. It is suggested that the stabilization of existing interfaces in multimeric proteins or the formation of new complexes in monomeric polypeptides might become effective strategies to prevent disease-linked aggregation of globular proteins. PMID:19696882

Interaction of Leptospira Elongation Factor Tu with Plasminogen and Complement Factor H: A Metabolic Leptospiral Protein with Moonlighting Activities

PubMed Central

Abe, Cecília M.; Monaris, Denize; Morais, Zenaide M.; Souza, Gisele O.; Vasconcellos, Sílvio A.; Isaac, Lourdes; Abreu, Patrícia A. E.; Barbosa, Angela S.

2013-01-01

The elongation factor Tu (EF-Tu), an abundant bacterial protein involved in protein synthesis, has been shown to display moonlighting activities. Known to perform more than one function at different times or in different places, it is found in several subcellular locations in a single organism, and may serve as a virulence factor in a range of important human pathogens. Here we demonstrate that Leptospira EF-Tu is surface-exposed and performs additional roles as a cell-surface receptor for host plasma proteins. It binds plasminogen in a dose-dependent manner, and lysine residues are critical for this interaction. Bound plasminogen is converted to active plasmin, which, in turn, is able to cleave the natural substrates C3b and fibrinogen. Leptospira EF-Tu also acquires the complement regulator Factor H (FH). FH bound to immobilized EF-Tu displays cofactor activity, mediating C3b degradation by Factor I (FI). In this manner, EF-Tu may contribute to leptospiral tissue invasion and complement inactivation. To our knowledge, this is the first description of a leptospiral protein exhibiting moonlighting activities. PMID:24312361

Isolation of a pH-Sensitive IgNAR Variable Domain from a Yeast-Displayed, Histidine-Doped Master Library.

PubMed

Könning, Doreen; Zielonka, Stefan; Sellmann, Carolin; Schröter, Christian; Grzeschik, Julius; Becker, Stefan; Kolmar, Harald

2016-04-01

In recent years, engineering of pH-sensitivity into antibodies as well as antibody-derived fragments has become more and more attractive for biomedical and biotechnological applications. Herein, we report the isolation of the first pH-sensitive IgNAR variable domain (vNAR), which was isolated from a yeast-displayed, semi-synthetic master library. This strategy enables the direct identification of pH-dependent binders from a histidine-enriched CDR3 library. Displayed vNAR variants contained two histidine substitutions on average at random positions in their 12-residue CDR3 loop. Upon screening of seven rounds against the proof-of-concept target EpCAM (selection for binding at pH 7.4 and decreased binding at pH 6.0), a single clone was obtained that showed specific and pH-dependent binding as characterized by yeast surface display and biolayer interferometry. Potential applications for such pH-dependent vNAR domains include their employment in tailored affinity chromatography, enabling mild elution protocols. Moreover, utilizing a master library for the isolation of pH-sensitive vNAR variants may be a generic strategy to obtain binding entities with prescribed characteristics for applications in biotechnology, diagnostics, and therapy.

A direct biocombinatorial strategy toward next generation, mussel-glue inspired saltwater adhesives.

PubMed

Wilke, Patrick; Helfricht, Nicolas; Mark, Andreas; Papastavrou, Georg; Faivre, Damien; Börner, Hans G

2014-09-10

Biological materials exhibit remarkable, purpose-adapted properties that provide a source of inspiration for designing new materials to meet the requirements of future applications. For instance, marine mussels are able to attach to a broad spectrum of hard surfaces under hostile conditions. Controlling wet-adhesion of synthetic macromolecules by analogue processes promises to strongly impact materials sciences by offering advanced coatings, adhesives, and glues. The de novo design of macromolecules to mimic complex aspects of mussel adhesion still constitutes a challenge. Phage display allows material scientists to design specifically interacting molecules with tailored affinity to material surfaces. Here, we report on the integration of enzymatic processing steps into phage display biopanning to expand the biocombinatorial procedure and enable the direct selection of enzymatically activable peptide adhesion domains. Adsorption isotherms and single molecule force spectroscopy show that those de novo peptides mimic complex aspects of bioadhesion, such as enzymatic activation (by tyrosinase), the switchability from weak to strong binders, and adsorption under hostile saltwater conditions. Furthermore, peptide-poly(ethylene oxide) conjugates are synthesized to generate protective coatings, which possess anti-fouling properties and suppress irreversible interactions with blood-plasma protein cocktails. The extended phage display procedure provides a generic way to non-natural peptide adhesion domains, which not only mimic nature but also improve biological sequence sections extractable from mussel-glue proteins. The de novo peptides manage to combine several tasks in a minimal 12-mer sequence and thus pave the way to overcome major challenges of technical wet glues.

Programmable colloidal molecules from sequential capillarity-assisted particle assembly

PubMed Central

Ni, Songbo; Leemann, Jessica; Buttinoni, Ivo; Isa, Lucio; Wolf, Heiko

2016-01-01

The assembly of artificial nanostructured and microstructured materials which display structures and functionalities that mimic nature’s complexity requires building blocks with specific and directional interactions, analogous to those displayed at the molecular level. Despite remarkable progress in synthesizing “patchy” particles encoding anisotropic interactions, most current methods are restricted to integrating up to two compositional patches on a single “molecule” and to objects with simple shapes. Currently, decoupling functionality and shape to achieve full compositional and geometrical programmability remains an elusive task. We use sequential capillarity-assisted particle assembly which uniquely fulfills the demands described above. This is a new method based on simple, yet essential, adaptations to the well-known capillary assembly of particles over topographical templates. Tuning the depth of the assembly sites (traps) and the surface tension of moving droplets of colloidal suspensions enables controlled stepwise filling of traps to “synthesize” colloidal molecules. After deposition and mechanical linkage, the colloidal molecules can be dispersed in a solvent. The template’s shape solely controls the molecule’s geometry, whereas the filling sequence independently determines its composition. No specific surface chemistry is required, and multifunctional molecules with organic and inorganic moieties can be fabricated. We demonstrate the “synthesis” of a library of structures, ranging from dumbbells and triangles to units resembling bar codes, block copolymers, surfactants, and three-dimensional chiral objects. The full programmability of our approach opens up new directions not only for assembling and studying complex materials with single-particle-level control but also for fabricating new microscale devices for sensing, patterning, and delivery applications. PMID:27051882

Hewlett-Packard's Approaches to Full Color Reflective Displays

NASA Astrophysics Data System (ADS)

Gibson, Gary

2012-02-01

Reflective displays are desirable in applications requiring low power or daylight readability. However, commercial reflective displays are currently either monochrome or capable of only dim color gamuts. Low cost, high-quality color technology would be rapidly adopted in existing reflective display markets and would enable new solutions in areas such as retail pricing and outdoor digital signage. Technical breakthroughs are required to enable bright color gamuts at reasonable cost. Pixel architectures that rely on pure reflection from a single layer of side-by-side primary-color sub-pixels use only a fraction of the display area to reflect incident light of a given color and are, therefore, unacceptably dark. Reflective devices employing stacked color primaries offer the possibility of a somewhat brighter color gamut but can be more complex to manufacture. In this talk, we describe HP's successes in addressing these fundamental challenges and creating both high performance stacked-primary reflective color displays as well as inexpensive single layer prototypes that provide good color. Our stacked displays utilize a combination of careful light management techniques, proprietary high-contrast electro-optic shutters, and highly transparent active-matrix TFT arrays based on transparent metal oxides. They also offer the possibility of relatively low cost manufacturing through roll-to-roll processing on plastic webs. To create even lower cost color displays with acceptable brightness, we have developed means for utilizing photoluminescence to make more efficient use of ambient light in a single layer device. Existing reflective displays create a desired color by reflecting a portion of the incident spectrum while absorbing undesired wavelengths. We have developed methods for converting the otherwise-wasted absorbed light to desired wavelengths via tailored photoluminescent composites. Here we describe a single active layer prototype display that utilizes these materials along with an innovative optical out-coupling scheme. Further benefits of our approach include means for highly power-efficient back-lighting under low ambient light conditions and the possibility of video rate operation.

Crystallographic control of surface structure on the sectoral zoning of iron in a diopside from Orford nickel mine (Quebec), Canada

NASA Astrophysics Data System (ADS)

Paquette, J.; Zangooi, A.; Thornton, K.

2004-05-01

The influence of surface structure on partitioning between mineral and melt (or solution) has been noted by other workers in a handful of minerals, including calcite, dolomite, apatite, topaz and diamond. Each one of these minerals displays at least one crystallographic face where steps present during crystal growth are not equivalent by symmetry. When this is the case, sectors grown at the edge of these steps commonly show differential incorporation of minor or trace elements. In the diopside investigated here, electron probe microanalyses performed on the as-grown (100) surface of several crystals show concentric and sectoral zoning defined by variations in Fe content. Atomic force microscopy (AFM) was used to study the surfaces of the three crystallographic forms present on the diopside crystals, with the goal of relating the compositional zoning to the surface structure of the faces. The dominant {100} faces are covered with growth hillocks consisting of four vicinal faces defined by steps parallel to [010] and [001]. The steps are often bunched into macrosteps and the resulting hillocks are visible optically. The steps along the two crystallographic directions show significant differences in straightness and smoothness that indicate non-equivalent kinetics. The wavier steps correspond to Fe-enriched areas within the {100} sectors. The {010} faces, next in morphological importance, are dominated by a single step orientation and show no differential incorporation. They display topography related to polysynthetic twinning. The {110} faces are much smaller and very few show resolvable steps. Sector zoning (i.e. diffential partitioning among non-equivalent crystallographic faces) has been described in the past from pyroxenes. Explanations have invoked either differences in surface structure among non-equivalent faces or their unequal growth rates. This particular occurrence indicates that trace element incorporation is, in fact, highly site-specific and that significant compositioinal zoning can be induced on a single face without invoking the effect of growth rate. The natural diopside crystals from the Orford nickel mine (Brompton, Quebec) show a unusual bladed habit flattened on {100} faces. Exceptional fluid chemistry during crystallization may therefore be required for the persistence of steps responsible for differential incorporation. Nevertheless, whenever this zoning is present, the trace element involved cannot be expected to reflect thermodynamic equilibrium between the solid and the fluid from which it crystallized.

Controlling surface-segregation of a polymer to display carboxy groups on an outermost surface using perfluoroacyl groups.

PubMed

Nishimori, Keisuke; Kitahata, Shigeru; Nishino, Takashi; Maruyama, Tatsuo

2018-05-10

Controlling the surface properties of solid polymers is important for practical applications. We here succeeded in controlling the surface segregation of polymers to display carboxy groups on an outermost surface, which allowed the covalent immobilization of functional molecules via the carboxy groups on a substrate surface. Random methacrylate-based copolymers containing carboxy groups, in which carboxy groups were protected with perfluoroacyl (Rf) groups, were dip-coated on acrylic substrate surfaces. X-ray photoelectron spectroscopy and contact-angle measurements revealed that the Rf groups were segregated to the outermost surface of the dip-coated substrates. The Rf groups were removed by hydrolysis of the Rf esters in the copolymers, resulting in the display of carboxy groups on the surface. The quantification of carboxy groups on a surface revealed that the carboxy groups were reactive to a water-soluble solute in aqueous solution. The surface segregation was affected by the molecular structure of the copolymer used for dip-coating.

Aircraft control position indicator

NASA Technical Reports Server (NTRS)

Dennis, Dale V. (Inventor)

1987-01-01

An aircraft control position indicator was provided that displayed the degree of deflection of the primary flight control surfaces and the manner in which the aircraft responded. The display included a vertical elevator dot/bar graph meter display for indication whether the aircraft will pitch up or down, a horizontal aileron dot/bar graph meter display for indicating whether the aircraft will roll to the left or to the right, and a horizontal dot/bar graph meter display for indicating whether the aircraft will turn left or right. The vertical and horizontal display or displays intersect to form an up/down, left/right type display. Internal electronic display driver means received signals from transducers measuring the control surface deflections and determined the position of the meter indicators on each dot/bar graph meter display. The device allows readability at a glance, easy visual perception in sunlight or shade, near-zero lag in displaying flight control position, and is not affected by gravitational or centrifugal forces.

Developments toward an 18% efficient silicon solar cell

NASA Technical Reports Server (NTRS)

Meulenberg, A., Jr.

1983-01-01

Limitations to increased open-circuit voltage were identified and experimentally verified for 0.1 ohm-cm solar cells with heavily doped emitters. After major reduction in the dark current contribution from the metal-silicon interface of the grid contacts, the surface recombination velocity of the oxide-silicon interface of shallow junction solar cells is the limiting factor. In deep junction solar cells, where the junction field does not aid surface collection, the emitter bulk is the limiting factor. Singly-diffused, shallow junction cells have been fabricated with open circuit voltages in excess of 645 mV. Double-diffusion shallow and deep junctions cells have displayed voltages above 650 mV. MIS solar cells formed on 0.1 ohm-cm substrates have exibited the lowest dark currents produced in the course of the contract work.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breznay, Nicholas P.; Hayes, Ian M.; Ramshaw, B. J.

In this work, we study magnetotransport properties of the electron-doped superconductor Pr 2-xCe xCuO 4±δ with x = 0.14 in magnetic fields up to 92 T, and observe Shubnikov-de Haas magnetic quantum oscillations. The oscillations display a single frequency F = 255 ± 10 T, indicating a small Fermi pocket that is ~1 % of the two-dimensional Brillouin zone and consistent with a Fermi surface reconstructed from the large holelike cylinder predicted for these layered materials. Despite the low nominal doping, all electronic properties including the effective mass and Hall effect are consistent with overdoped compounds. In conclusion, our studymore » demonstrates that the exceptional chemical control afforded by high quality thin films will enable Fermi surface studies deep into the overdoped cuprate phase diagram.« less

77 FR 49708 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-17

... done in accordance with Figure 24, Steel Part Surface Inspection (Impedance Plane Display), Subject 51... 30, 2012. (ii) Figure 24, Steel Part Surface Inspection (Impedance Plane Display), Subject 51-00-00...

Multichannel analysis of surface waves

USGS Publications Warehouse

Park, C.B.; Miller, R.D.; Xia, J.

1999-01-01

The frequency-dependent properties of Rayleigh-type surface waves can be utilized for imaging and characterizing the shallow subsurface. Most surface-wave analysis relies on the accurate calculation of phase velocities for the horizontally traveling fundamental-mode Rayleigh wave acquired by stepping out a pair of receivers at intervals based on calculated ground roll wavelengths. Interference by coherent source-generated noise inhibits the reliability of shear-wave velocities determined through inversion of the whole wave field. Among these nonplanar, nonfundamental-mode Rayleigh waves (noise) are body waves, scattered and nonsource-generated surface waves, and higher-mode surface waves. The degree to which each of these types of noise contaminates the dispersion curve and, ultimately, the inverted shear-wave velocity profile is dependent on frequency as well as distance from the source. Multichannel recording permits effective identification and isolation of noise according to distinctive trace-to-trace coherency in arrival time and amplitude. An added advantage is the speed and redundancy of the measurement process. Decomposition of a multichannel record into a time variable-frequency format, similar to an uncorrelated Vibroseis record, permits analysis and display of each frequency component in a unique and continuous format. Coherent noise contamination can then be examined and its effects appraised in both frequency and offset space. Separation of frequency components permits real-time maximization of the S/N ratio during acquisition and subsequent processing steps. Linear separation of each ground roll frequency component allows calculation of phase velocities by simply measuring the linear slope of each frequency component. Breaks in coherent surface-wave arrivals, observable on the decomposed record, can be compensated for during acquisition and processing. Multichannel recording permits single-measurement surveying of a broad depth range, high levels of redundancy with a single field configuration, and the ability to adjust the offset, effectively reducing random or nonlinear noise introduced during recording. A multichannel shot gather decomposed into a swept-frequency record allows the fast generation of an accurate dispersion curve. The accuracy of dispersion curves determined using this method is proven through field comparisons of the inverted shear-wave velocity (??(s)) profile with a downhole ??(s) profile.Multichannel recording is an efficient method of acquiring ground roll. By displaying the obtained information in a swept-frequency format, different frequency components of Rayleigh waves can be identified by distinctive and simple coherency. In turn, a seismic surface-wave method is derived that provides a useful noninvasive tool, where information about elastic properties of near-surface materials can be effectively obtained.

Design and Testing of an Unlimited Field-of-regard Synthetic Vision Head-worn Display for Commercial Aircraft Surface Operations

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Shelton, Kevin J.; Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Norman, Robert M.

2007-01-01

Experiments and flight tests have shown that a Head-Up Display (HUD) and a head-down, electronic moving map (EMM) can be enhanced with Synthetic Vision for airport surface operations. While great success in ground operations was demonstrated with a HUD, the research noted that two major HUD limitations during ground operations were their monochrome form and limited, fixed field of regard. A potential solution to these limitations found with HUDs may be emerging Head Worn Displays (HWDs). HWDs are small, lightweight full color display devices that may be worn without significant encumbrance to the user. By coupling the HWD with a head tracker, unlimited field-of-regard may be realized for commercial aviation applications. In the proposed paper, the results of two ground simulation experiments conducted at NASA Langley are summarized. The experiments evaluated the efficacy of head-worn display applications of Synthetic Vision and Enhanced Vision technology to enhance transport aircraft surface operations. The two studies tested a combined six display concepts: (1) paper charts with existing cockpit displays, (2) baseline consisting of existing cockpit displays including a Class III electronic flight bag display of the airport surface; (3) an advanced baseline that also included displayed traffic and routing information, (4) a modified version of a HUD and EMM display demonstrated in previous research; (5) an unlimited field-of-regard, full color, head-tracked HWD with a conformal 3-D synthetic vision surface view; and (6) a fully integrated HWD concept. The fully integrated HWD concept is a head-tracked, color, unlimited field-of-regard concept that provides a 3-D conformal synthetic view of the airport surface integrated with advanced taxi route clearance, taxi precision guidance, and data-link capability. The results of the experiments showed that the fully integrated HWD provided greater path performance compared to using paper charts alone. Further, when comparing the HWD with the HUD concept, there were no differences in path performance. In addition, the HWD and HUD concepts were rated via paired-comparisons the same in terms of situational awareness and workload. However, there were over twice as many taxi incursion events with the HUD than the HWD.

Extraordinary epitaxial alignment of graphene islands on Au(111)

NASA Astrophysics Data System (ADS)

Wofford, Joseph M.; Starodub, Elena; Walter, Andrew L.; Nie, Shu; Bostwick, Aaron; Bartelt, Norman C.; Thürmer, Konrad; Rotenberg, Eli; McCarty, Kevin F.; Dubon, Oscar D.

2012-05-01

Pristine, single-crystalline graphene displays a unique collection of remarkable electronic properties that arise from its two-dimensional, honeycomb structure. Using in situ low-energy electron microscopy, we show that when deposited on the (111) surface of Au carbon forms such a structure. The resulting monolayer, epitaxial film is formed by the coalescence of dendritic graphene islands that nucleate at a high density. Over 95% of these islands can be identically aligned with respect to each other and to the Au substrate. Remarkably, the dominant island orientation is not the better lattice-matched 30° rotated orientation but instead one in which the graphene [01] and Au [011] in-plane directions are parallel. The epitaxial graphene film is only weakly coupled to the Au surface, which maintains its reconstruction under the slightly p-type doped graphene. The linear electronic dispersion characteristic of free-standing graphene is retained regardless of orientation. That a weakly interacting, non-lattice matched substrate is able to lock graphene into a particular orientation is surprising. This ability, however, makes Au(111) a promising substrate for the growth of single crystalline graphene films.

Polymer-Based Protein Engineering: Synthesis and Characterization of Armored, High Graft Density Polymer-Protein Conjugates.

PubMed

Carmali, Sheiliza; Murata, Hironobu; Cummings, Chad; Matyjaszewski, Krzysztof; Russell, Alan J

2017-01-01

Atom transfer radical polymerization (ATRP) from the surface of a protein can generate remarkably dense polymer shells that serve as armor and rationally tune protein function. Using straightforward chemistry, it is possible to covalently couple or display multiple small molecule initiators onto a protein surface. The chemistry is fine-tuned to be sequence specific (if one desires a single targeted site) at controlled density. Once the initiator is anchored on the protein surface, ATRP is used to grow polymers on protein surface, in situ. The technique is so powerful that a single-protein polymer conjugate molecule can contain more than 90% polymer coating by weight. If desired, stimuli-responsive polymers can be "grown" from the initiated sites to prepare enzyme conjugates that respond to external triggers such as temperature or pH, while still maintaining enzyme activity and stability. Herein, we focus mainly on the synthesis of chymotrypsin-polymer conjugates. Control of the number of covalently coupled initiator sites by changing the stoichiometric ratio between enzyme and the initiator during the synthesis of protein-initiator complexes allowed fine-tuning of the grafting density. For example, very high grafting density chymotrypsin conjugates were prepared from protein-initiator complexes to grow the temperature-responsive polymers, poly(N-isopropylacrylamide), and poly[N,N'-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate]. Controlled growth of polymers from protein surfaces enables one to predictably manipulate enzyme kinetics and stability without the need for molecular biology-dependent mutagenesis. © 2017 Elsevier Inc. All rights reserved.

Preparation And Evaluation Techniques of Porous Materials and Mixed Matrix Membranes for Targeted CO2 Separation Applications

NASA Astrophysics Data System (ADS)

Tessema, Tsemre Dingel Mesfin

The use of porous sorbents for physisorptive capture of CO2 from gas mixtures has been deemed attractive due to the low energy penalty associated with recycling of such materials. Porous organic polymers (POPs) have emerged as promising candidates with potential in the treatment of pre- and post- fuel combustion processes to separate CO2 from gas mixtures. Concurrently, significant advances have been made in establishing calculation methods that evaluate the practicality of porous sorbents for targeted gas separation applications. However, these methods rely on single gas adsorption isotherms without accounting for the dynamic gas mixtures encountered in real-life applications. To this end, the design and application of a dynamic gas mixture breakthrough apparatus to assess the CO2 separation performance of a new class of heteroatom (N and O) doped porous carbons derived from a Pyrazole precursor from flue gas mixtures is presented. Here in, two new benzimidazole linked polymers (BILPs) have been designed and synthesized. These polymers display high surface while their imidazole functionality and microporous nature resulted in high CO2 uptakes and isosteric heat of adsorption (Qst). BILP-30 displayed very good selectivity for CO2 in flue gas while BILP-31 was superior in CO2 separation from landfill gas mixtures at 298 K and 1 bar. Additionally, a new POP incorporating a highly conjugated pyrene core into a polymer framework linked by azo-bonds is presented. Azo-Py displays a nanofibrous morphology induced by the pi-pi stacking of the electron rich pyrene core. Due to its high surface area and microporous nature, Azo-Py displays impressive CO2 uptakes at 298 K and 1 bar. Evaluation of the S value for CO2 separation of Azo-Py revealed competitive values for flue gas and landfill gas at 298 K and 1 bar. Finally, a highly cross-linked benzimidazole linked polymer, BILP-4, was successfully incorporated into MatrimidRTM polymer to form a series of new mixed matrix membranes. The surface functionality of BILP-4 was exploited to enhance the interaction with MatrimidRTM polymer matrix to produce robust MMMs which displayed significantly improved CO2 gas permeabilities and ideal selectivities for CO 2/N2.

Mechanism of formation of humus coatings on mineral surfaces 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina

USGS Publications Warehouse

Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.; Sperline, R.P.; Song, Y.

1996-01-01

Hydrophobic and hydrophilic fractions were isolated from a compost leachate. The adsorption isotherms of both fractions on alumina were measured by attenuated total reflectance infrared spectroscopy. The shapes of the adsorption isotherms of the two fractions were different. The isotherms for the hydrophilic fraction showed little change in surface excess with increasing solution concentration above 4 mg L-1. The isotherms for the hydrophobic fraction, on the other hand, displayed a marked increase in surface excess with increasing solution concentration. This increase is evidence for the formation of aggregates (admicelles or hemimicelles) on the alumina surface. Linear dichroism calculations indicated that more of the carboxylate groups in the adsorbed hydrophobic molecules than in the absorbed hydrophilic fraction were free to rotate. The hindered rotation of the carboxylate groups in the adsorbed hydrophilic-fraction molecules probably indicates that these groups are bound to surface aluminum ions by a bidentate mechanism in which the two oxygen atoms of a single carboxylate group bind to separate aluminum ions.

RGD Peptide Cell-Surface Display Enhances the Targeting and Therapeutic Efficacy of Attenuated Salmonella-mediated Cancer Therapy.

PubMed

Park, Seung-Hwan; Zheng, Jin Hai; Nguyen, Vu Hong; Jiang, Sheng-Nan; Kim, Dong-Yeon; Szardenings, Michael; Min, Jung Hyun; Hong, Yeongjin; Choy, Hyon E; Min, Jung-Joon

2016-01-01

Bacteria-based anticancer therapies aim to overcome the limitations of current cancer therapy by actively targeting and efficiently removing cancer. To achieve this goal, new approaches that target and maintain bacterial drugs at sufficient concentrations during the therapeutic window are essential. Here, we examined the tumor tropism of attenuated Salmonella typhimurium displaying the RGD peptide sequence (ACDCRGDCFCG) on the external loop of outer membrane protein A (OmpA). RGD-displaying Salmonella strongly bound to cancer cells overexpressing αvβ3, but weakly bound to αvβ3-negative cancer cells, suggesting the feasibility of displaying a preferential homing peptide on the bacterial surface. In vivo studies revealed that RGD-displaying Salmonellae showed strong targeting efficiency, resulting in the regression in αvβ3-overexpressing cancer xenografts, and prolonged survival of mouse models of human breast cancer (MDA-MB-231) and human melanoma (MDA-MB-435). Thus, surface engineering of Salmonellae to display RGD peptides increases both their targeting efficiency and therapeutic effect.

77 FR 31762 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

..., Steel Part Surface Inspection (Impedance Plane Display), of Part 6, Eddy Current, of the Boeing 707, 720... Subject 51-00-00 Figure 24, Steel Part Surface Inspection (Impedance Plane Display), of Part 6, Eddy...

Remote estimation of the surface characteristics and energy balance over an urban-rural area and the effects of surface heat flux on plume spread and concentration. M.S. Thesis; [St. Louis, Missouri, the Land Between the Lakes, Kentucky and Clarksville, Tennessee

NASA Technical Reports Server (NTRS)

Dicristofaro, D. C. (Principal Investigator)

1980-01-01

A one dimensional boundary layer model was used in conjunction with satellite derived infrared surface temperatures to deduce values of moisture availability, thermal inertia, heat and evaporative fluxes. The Penn State satellite image display system, a sophisticated image display facility, was used to remotely sense these various parameters for three cases: St. Louis, Missouri; the Land Between the Lakes, Kentucky; and Clarksville, Tennessee. The urban centers displayed the maximum daytime surface temperatures which correspond to the minimum values of moisture availability. The urban center of St. Louis and the bodies of water displayed the maximum nighttime surface temperatures which correspond to the maximum thermal inertia values. It is shown that moisture availability and thermal inertia are very much responsible for the formation of important temperature variations over the urban rural complex.

Bacterial whole-cell biocatalysts by surface display of enzymes: toward industrial application.

PubMed

Schüürmann, Jan; Quehl, Paul; Festel, Gunter; Jose, Joachim

2014-10-01

Despite the first report on the bacterial display of a recombinant peptide appeared almost 30 years ago, industrial application of cells with surface-displayed enzymes is still limited. To display an enzyme on the surface of a living cell bears several advantages. First of all, neither the substrate nor the product of the enzymatic reaction needs to cross a membrane barrier. Second, the enzyme being linked to the cell can be separated from the reaction mixture and hence the product by simple centrifugation. Transfer to a new substrate preparation results in multiple cycles of enzymatic conversion. Finally, the anchoring in a matrix, in this case, the cell envelope stabilizes the enzyme and makes it less accessible to proteolytic degradation and material adsorption resulting in continuous higher activities. These advantages in common need to balance some disadvantages before this application can be taken into account for industrial processes, e.g., the exclusion of the enzyme from the cellular metabolome and hence from redox factors or other co-factors that need to be supplied. Therefore, this digest describes the different systems in Gram-positive and Gram-negative bacteria that have been used for the surface display of enzymes so far and focuses on examples among these which are suitable for industrial purposes or for the production of valuable resources, not least in order to encourage a broader application of whole-cell biocatalysts with surface-displayed enzymes.

MEMS tactile display: from fabrication to characterization

NASA Astrophysics Data System (ADS)

Miki, Norihisa; Kosemura, Yumi; Watanabe, Junpei; Ishikawa, Hiroaki

2014-03-01

We report fabrication and characterization of MEMS-based tactile display that can display users various tactile information, such as Braille codes and surface textures. The display consists of 9 micro-actuators that are equipped with hydraulic displacement amplification mechanism (HDAM) to achieve large enough displacement to stimulate the human tactile receptors. HDAM encapsulates incompressible liquids. We developed a liquid encapsulation process, which we termed as Bonding-in-Liquid Technique, where bonding with a UV-curable resin in glycerin is conducted in the liquid, which prevented interfusion of air bubbles and deformation of the membrane during the bonding. HDAM successfully amplified the displacement generated by piezoelectric actuators by a factor of 6. The display could virtually produce "rough" and "smooth" surfaces, by controlling the vibration frequency, displacement, and the actuation periods of an actuator until the adjacent actuator was driven. We introduced a sample comparison method to characterize the surfaces, which involves human tactile sensation. First, we prepared samples whose mechanical properties are known. We displayed a surface texture to the user by controlling the parameters and then, the user selects a sample that has the most similar surface texture. By doing so, we can correlate the parameters with the mechanical properties of the sample as well as find the sets of the parameters that can provide similar tactile information to many users. The preliminary results with respect to roughness and hardness is presented.

Differentiating and characterizing geminal silanols in silicas by (29)Si NMR spectroscopy.

PubMed

Murray, David K

2010-12-01

Single and geminal hydroxyl species in silicas have been characterized using solid-state (29)Si NMR spectroscopy. Differentiating hydroxyl types is important in understanding their roles in chemical toxicity mechanisms for inhaled crystalline silicas responsible for silicosis. (1)H-(29)Si cross polarization NMR spectroscopy has been employed to obtain (29)Si NMR chemical shift data and signal accrual and relaxation characteristics. Spectral deconvolution is used to examine relative single and geminal hydroxyl resonance areas for a series of representative silicas and silica gels. Silicon-containing materials examined include 1878a quartz, and 1879a cristobalite from the National Institute for Science and Technology, kaolin, and several widely used respirable silicas and silica gels. Geminal hydroxyls were observed in every case, with relative resonance areas accounting for 21-65% of total hydroxyl signals. Factors affecting relative areas measured as a function of contact time, relaxation, and surface area are discussed. Subsequent (29)Si and (31)P NMR studies of a silica coated with various sodium hydrogen phosphates show preferential single silanol-phosphate interaction for basic phosphates, and oligomerization products for acidic phosphates. Geminal hydroxyl resonance areas displayed significant error (4-17%) for low surface area silicas, limiting this method to studies exhibiting major changes in chemical or spectroscopic properties. Published by Elsevier Inc.

Interplay between type IV pili activity and exopolysaccharides secretion controls motility patterns in single cells of Myxococcus xanthus

PubMed Central

Hu, Wei; Gibiansky, Maxsim L.; Wang, Jing; Wang, Chuandong; Lux, Renate; Li, Yuezhong; Wong, Gerard C. L.; Shi, Wenyuan

2016-01-01

Myxococcus xanthus performs coordinated social motility of cell groups through the extension and retraction of type IV pili (TFP) on solid surfaces, which requires both TFP and exopolysaccharides (EPS). By submerging cells in a liquid medium containing 1% methylcellulose, M. xanthus TFP-driven motility was induced in isolated cells and independently of EPS. We measured and analyzed the movements of cells using community tracking algorithms, which combine single-cell resolution with statistics from large sample populations. Cells without significant multi-cellular social interactions have surprisingly complex behaviors: EPS− cells exhibited a pronounced increase in the tendency to stand vertically and moved with qualitatively different characteristics than other cells. A decrease in the EPS secretion of cells correlates with a higher instantaneous velocity, but with lower directional persistence in trajectories. Moreover, EPS− cells do not adhere to the surface as strongly as wild-type and EPS overproducing cells, and display a greater tendency to have large deviations between the direction of movement and the cell axis, with cell velocity showing only minimal dependence on the direction of movement. The emerging picture is that EPS does not simply provide rheological resistance to a single mechanism but rather that the availability of EPS impacts motility pattern. PMID:26821939

Display of travelling 3D scenes from single integral-imaging capture

NASA Astrophysics Data System (ADS)

Martinez-Corral, Manuel; Dorado, Adrian; Hong, Seok-Min; Sola-Pikabea, Jorge; Saavedra, Genaro

2016-06-01

Integral imaging (InI) is a 3D auto-stereoscopic technique that captures and displays 3D images. We present a method for easily projecting the information recorded with this technique by transforming the integral image into a plenoptic image, as well as choosing, at will, the field of view (FOV) and the focused plane of the displayed plenoptic image. Furthermore, with this method we can generate a sequence of images that simulates a camera travelling through the scene from a single integral image. The application of this method permits to improve the quality of 3D display images and videos.

Control strategies for planetary rover motion and manipulator control

NASA Technical Reports Server (NTRS)

Trautwein, W.

1973-01-01

An unusual insect-like vehicle designed for planetary surface exploration is made the occasion for a discussion of control concepts in path selection, hazard detection, obstacle negotiation, and soil sampling. A control scheme which actively articulates the pitching motion between a single-loop front module and a dual loop rear module leads to near optimal behavior in soft soil; at the same time the vehicle's front module acts as a reliable tactile forward probe with a detection range much longer than the stopping distance. Some optimal control strategies are discussed, and the photos of a working scale model are displayed.

Surface modification for enhanced silanation of zirconia ceramics.

PubMed

Piascik, J R; Swift, E J; Thompson, J Y; Grego, S; Stoner, B R

2009-09-01

The overall goal of this research was to develop a practical method to chemically modify the surface of high strength dental ceramics (i.e. zirconia) to facilitate viable, robust adhesive bonding using commercially available silanes and resin cements. Investigation focused on a novel approach to surface functionalize zirconia with a Si(x)O(y) "seed" layer that would promote chemical bonding with traditional silanes. ProCAD and ZirCAD blocks were bonded to a dimensionally similar composite block using standard techniques designed for silica-containing materials (silane and resin cement). ZirCAD blocks were treated with SiCl4 by vapor deposition under two different conditions prior to bonding. Microtensile bars were prepared and subjected to tensile forces at a crosshead speed of 1 mm/min scanning electron microscopy was used to analyze fracture surfaces and determine failure mode; either composite cohesive failure (partial or complete cohesive failure within composite) or adhesive failure (partial or complete adhesive failure). Peak stress values were analyzed using single-factor ANOVA (p<0.05). Microtensile testing results revealed that zirconia with a surface treatment of 2.6 nm Si(x)O(y) thick "seed" layer was similar in strength to the porcelain group (control). Analysis of failure modes indicated the above groups displayed higher percentages of in-composite failures. Other groups tested had lower strength values and displayed adhesive failure characteristics. Mechanical data support that utilizing a gas-phase chloro-silane pretreatment to deposit ultra-thin silica-like seed layers can improve adhesion to zirconia using traditional silanation and bonding techniques. This technology could have clinical impact on how high strength dental materials are used today.

Interactive Display of Surfaces Using Subdivision Surfaces and Wavelets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duchaineau, M A; Bertram, M; Porumbescu, S

2001-10-03

Complex surfaces and solids are produced by large-scale modeling and simulation activities in a variety of disciplines. Productive interaction with these simulations requires that these surfaces or solids be viewable at interactive rates--yet many of these surfaced solids can contain hundreds of millions of polygondpolyhedra. Interactive display of these objects requires compression techniques to minimize storage, and fast view-dependent triangulation techniques to drive the graphics hardware. In this paper, we review recent advances in subdivision-surface wavelet compression and optimization that can be used to provide a framework for both compression and triangulation. These techniques can be used to produce suitablemore » approximations of complex surfaces of arbitrary topology, and can be used to determine suitable triangulations for display. The techniques can be used in a variety of applications in computer graphics, computer animation and visualization.« less

Active Camouflage for Infantry Headwear Applications

DTIC Science & Technology

2007-02-01

incorporates a rewriteable display medium. Military, academic, and commercial groups are aiming at developing OLEDs for full- color flexible displays...as shown in Figure 7. Figure 7: Organic LED Prototype shown on a Flexible surface (Kincade, 2004). OLEDs are self-luminous and do not require...brighter, more stable color displays. The OLED manufacturing process is much more amenable to retaining optimum performance on a flexible surface

Method and System for Producing Full Motion Media to Display on a Spherical Surface

NASA Technical Reports Server (NTRS)

Starobin, Michael A. (Inventor)

2015-01-01

A method and system for producing full motion media for display on a spherical surface is described. The method may include selecting a subject of full motion media for display on a spherical surface. The method may then include capturing the selected subject as full motion media (e.g., full motion video) in a rectilinear domain. The method may then include processing the full motion media in the rectilinear domain for display on a spherical surface, such as by orienting the full motion media, adding rotation to the full motion media, processing edges of the full motion media, and/or distorting the full motion media in the rectilinear domain for instance. After processing the full motion media, the method may additionally include providing the processed full motion media to a spherical projection system, such as a Science on a Sphere system.

Exploratory visualization of astronomical data on ultra-high-resolution wall displays

NASA Astrophysics Data System (ADS)

Pietriga, Emmanuel; del Campo, Fernando; Ibsen, Amanda; Primet, Romain; Appert, Caroline; Chapuis, Olivier; Hempel, Maren; Muñoz, Roberto; Eyheramendy, Susana; Jordan, Andres; Dole, Hervé

2016-07-01

Ultra-high-resolution wall displays feature a very high pixel density over a large physical surface, which makes them well-suited to the collaborative, exploratory visualization of large datasets. We introduce FITS-OW, an application designed for such wall displays, that enables astronomers to navigate in large collections of FITS images, query astronomical databases, and display detailed, complementary data and documents about multiple sources simultaneously. We describe how astronomers interact with their data using both the wall's touchsensitive surface and handheld devices. We also report on the technical challenges we addressed in terms of distributed graphics rendering and data sharing over the computer clusters that drive wall displays.

Exploring the Predisposition of the Asian Eye to Development of Dry Eye.

PubMed

Craig, Jennifer P; Wang, Michael T M; Kim, Dabin; Lee, Jung Min

2016-07-01

To investigate the influence of eyelid shape on tear film quality, ocular surface characteristics and dry eye symptomatology by comparing Asian and Caucasian populations. Seventy-four age-matched participants were recruited in a cross-sectional study. Participants were classified into Asian single lid (ASL), Asian double lid (ADL), and Caucasian double lid (CDL) groups. Dry eye symptomatology, ocular surface characteristics, and tear film quality were evaluated in a single clinical session. Meibomian gland dropout was significantly greater in both the ASL and ADL groups than in the CDL group (all P<.05). A greater proportion of ASL and ADL participants exhibited incomplete blinking than CDL patients (all P<.05). There were no significant differences in tear film quality and dry eye symptomatology between the three groups (all P>.05). Exposed ocular surface area, lissamine green staining, and lid wiper epitheliopathy were significantly greater in the ADL group compared to the CDL group (all P<.05). The CDL group displayed significantly greater anterior blepharitis and lid telangiectasia grades compared to both ASL and ADL groups (all P<.05). A higher degree of meibomian gland dropout and incomplete blinking was observed in both Asian groups compared to the Caucasian group, potentially predisposing these groups to dry eye. Copyright © 2016 Elsevier Inc. All rights reserved.

Classification of sea ice types with single-band (33.6 GHz) airborne passive microwave imagery

NASA Astrophysics Data System (ADS)

Eppler, Duane T.; Farmer, L. Dennis; Lohanick, Alan W.; Hoover, Mervyn

1986-09-01

During March 1983 extensive high-quality airborne passive Ka band (33.6 GHz) microwave imagery and coincident high-resolution aerial photography were obtained of ice along a 378-km flight line in the Beaufort Sea. Analysis of these data suggests that four classes of winter surfaces can be distinguished solely on the basis of 33.6-GHz brightness temperature: open water, frazil, old ice, and young/first-year ice. New ice (excluding frazil) and nilas display brightness temperatures that overlap the range of temperatures characteristic of old ice and, to a lesser extent, young/first-year ice. Scenes in which a new ice or nilas are present in appreciable amounts are subject to substantial errors in classification if static measures of Ka band radiometric brightness temperature alone are considered. Textural characteristics of nilas and new ice, however, differ significantly from textural features characteristic of other ice types and probably can be used with brightness temperature data to classify ice type in high-resolution single-band microwave images. In any case, open water is radiometrically the coldest surface observed in any scene. Lack of overlap between brightness temperatures characteristic of other surfaces indicates that estimates of the areal extent of open water based on only 33.6-GHz brightness temperatures are accurate.

Tandem Fusion of Hepatitis B Core Antigen Allows Assembly of Virus-Like Particles in Bacteria and Plants with Enhanced Capacity to Accommodate Foreign Proteins

PubMed Central

Peyret, Hadrien; Gehin, Annick; Thuenemann, Eva C.; Blond, Donatienne; El Turabi, Aadil; Beales, Lucy; Clarke, Dean; Gilbert, Robert J. C.; Fry, Elizabeth E.; Stuart, David I.; Holmes, Kris; Stonehouse, Nicola J.; Whelan, Mike; Rosenberg, William; Lomonossoff, George P.; Rowlands, David J.

2015-01-01

The core protein of the hepatitis B virus, HBcAg, assembles into highly immunogenic virus-like particles (HBc VLPs) when expressed in a variety of heterologous systems. Specifically, the major insertion region (MIR) on the HBcAg protein allows the insertion of foreign sequences, which are then exposed on the tips of surface spike structures on the outside of the assembled particle. Here, we present a novel strategy which aids the display of whole proteins on the surface of HBc particles. This strategy, named tandem core, is based on the production of the HBcAg dimer as a single polypeptide chain by tandem fusion of two HBcAg open reading frames. This allows the insertion of large heterologous sequences in only one of the two MIRs in each spike, without compromising VLP formation. We present the use of tandem core technology in both plant and bacterial expression systems. The results show that tandem core particles can be produced with unmodified MIRs, or with one MIR in each tandem dimer modified to contain the entire sequence of GFP or of a camelid nanobody. Both inserted proteins are correctly folded and the nanobody fused to the surface of the tandem core particle (which we name tandibody) retains the ability to bind to its cognate antigen. This technology paves the way for the display of natively folded proteins on the surface of HBc particles either through direct fusion or through non-covalent attachment via a nanobody. PMID:25830365

An affinity improved single-chain antibody from phage display of a library derived from monoclonal antibodies detects fumonisins by immunoassay.

PubMed

Hu, Zu-Quan; Li, He-Ping; Wu, Ping; Li, Ya-Bo; Zhou, Zhu-Qing; Zhang, Jing-Bo; Liu, Jin-Long; Liao, Yu-Cai

2015-03-31

Fumonisin B analogs, particularly FB1, FB2, and FB3, are major mycotoxins found in cereals. Single-chain fragment variable (scFv) antibodies represent a promising alternative immunoassay system. A phage-displayed antibody library derived from four monoclonal antibodies (mAbs) generated against FB1 was used to screen high binding affinity scFv antibodies; the best candidate was designated H2. Surface plasmon resonance measurements confirmed that the H2 scFv displayed a 82-fold higher binding affinity than its parent mAb. Direct competitive enzyme-linked immunosorbent assay demonstrated that the H2 antibody could competitively bind to free FB1, FB2, and FB3, with an IC50 of 0.11, 0.04, and 0.10 μM, respectively; it had no cross-reactivity to deoxynivalenol, nivalenol and aflatoxin. Validation assays with naturally contaminated samples revealed a linear relationship between the H2 antibody-based assay results and chemical analysis results, that could be expressed as y=1.7072x+5.5606 (R(2)=0.8883). Homology modeling of H2 revealed a favorable binding structure highly complementary to the three fumonisins. Molecular docking analyses suggested that the preferential binding of the H2 scFv to FB2 was due to the presence of a hydrogen radical in its R1 position, leading to a proper electrostatic matching and hydrophobic interaction. The H2 scFv antibody can be used for the rapid, accurate, and specific detection of fumonisin contamination in agricultural samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Frequent pauses in Escherichia coli flagella elongation revealed by single cell real-time fluorescence imaging.

PubMed

Zhao, Ziyi; Zhao, Yifan; Zhuang, Xiang-Yu; Lo, Wei-Chang; Baker, Matthew A B; Lo, Chien-Jung; Bai, Fan

2018-05-14

The bacterial flagellum is a large extracellular protein organelle that extrudes from the cell surface. The flagellar filament is assembled from tens of thousands of flagellin subunits that are exported through the flagellar type III secretion system. Here, we measure the growth of Escherichia coli flagella in real time and find that, although the growth rate displays large variations at similar lengths, it decays on average as flagella lengthen. By tracking single flagella, we show that the large variations in growth rate occur as a result of frequent pauses. Furthermore, different flagella on the same cell show variable growth rates with correlation. Our observations are consistent with an injection-diffusion model, and we propose that an insufficient cytoplasmic flagellin supply is responsible for the pauses in flagellar growth in E. coli.

Coupling Binding to Catalysis: Using Yeast Cell Surface Display to Select Enzymatic Activities.

PubMed

Zhang, Keya; Bhuripanyo, Karan; Wang, Yiyang; Yin, Jun

2015-01-01

We find yeast cell surface display can be used to engineer enzymes by selecting the enzyme library for high affinity binding to reaction intermediates. Here we cover key steps of enzyme engineering on the yeast cell surface including library design, construction, and selection based on magnetic and fluorescence-activated cell sorting.

Microstructure, Texture, and Mechanical Behavior of As-cast Ni-Fe-W Matrix Alloy

NASA Astrophysics Data System (ADS)

Rao, A. Sambasiva; Manda, Premkumar; Mohan, M. K.; Nandy, T. K.; Singh, A. K.

2018-04-01

This article describes the tensile properties, flow, and work-hardening behavior of an experimental alloy 53Ni-29Fe-18W in as-cast condition. The microstructure of the alloy 53Ni-29Fe-18W displays single phase (fcc) in as-cast condition along with typical dendritic features. The bulk texture of the as-cast alloy reveals the triclinic sample symmetry and characteristic nature of coarse-grained materials. The alloy exhibits maximum strength ( σ YS and σ UTS) values along the transverse direction. The elongation values are maximum and minimum along the transverse and longitudinal directions, respectively. Tensile fracture surfaces of both the longitudinal and transverse samples display complete ductile fracture features. Two types of slip lines, namely, planar and intersecting, are observed in deformed specimens and the density of slip lines increases with increasing the amount of deformation. The alloy displays moderate in-plane anisotropy ( A IP) and reasonably low anisotropic index ( δ) values, respectively. The instantaneous or work-hardening rate curves portray three typical stages (I through III) along both the longitudinal and transverse directions. The alloy exhibits dislocation-controlled strain hardening during tensile testing, and slip is the predominant deformation mechanism.

An automatic calibration procedure for remote eye-gaze tracking systems.

PubMed

Model, Dmitri; Guestrin, Elias D; Eizenman, Moshe

2009-01-01

Remote gaze estimation systems use calibration procedures to estimate subject-specific parameters that are needed for the calculation of the point-of-gaze. In these procedures, subjects are required to fixate on a specific point or points at specific time instances. Advanced remote gaze estimation systems can estimate the optical axis of the eye without any personal calibration procedure, but use a single calibration point to estimate the angle between the optical axis and the visual axis (line-of-sight). This paper presents a novel automatic calibration procedure that does not require active user participation. To estimate the angles between the optical and visual axes of each eye, this procedure minimizes the distance between the intersections of the visual axes of the left and right eyes with the surface of a display while subjects look naturally at the display (e.g., watching a video clip). Simulation results demonstrate that the performance of the algorithm improves as the range of viewing angles increases. For a subject sitting 75 cm in front of an 80 cm x 60 cm display (40" TV) the standard deviation of the error in the estimation of the angles between the optical and visual axes is 0.5 degrees.

Isolation of Llama Antibody Fragments for Prevention of Dandruff by Phage Display in Shampoo

PubMed Central

Dolk, Edward; van der Vaart, Marcel; Lutje Hulsik, David; Vriend, Gert; de Haard, Hans; Spinelli, Silvia; Cambillau, Christian; Frenken, Leon; Verrips, Theo

2005-01-01

As part of research exploring the feasibility of using antibody fragments to inhibit the growth of organisms implicated in dandruff, we isolated antibody fragments that bind to a cell surface protein of Malassezia furfur in the presence of shampoo. We found that phage display of llama single-domain antibody fragments (VHHs) can be extended to very harsh conditions, such as the presence of shampoo containing nonionic and anionic surfactants. We selected several VHHs that bind to the cell wall protein Malf1 of M. furfur, a fungus implicated in causing dandruff. In addition to high stability in the presence of shampoo, these VHHs are also stable under other denaturing conditions, such as high urea concentrations. Many of the stable VHHs were found to contain arginine at position 44. Replacement of the native amino acid at position 44 with arginine in the most stable VHH that lacked this arginine resulted in a dramatic further increase in the stability. The combination of the unique properties of VHHs together with applied phage display and protein engineering is a powerful method for obtaining highly stable VHHs that can be used in a wide range of applications. PMID:15640220

Direct Integration of Dynamic Emissive Displays into Knitted Fabric Structures

NASA Astrophysics Data System (ADS)

Bellingham, Alyssa

Smart textiles are revolutionizing the textile industry by combining technology into fabric to give clothing new abilities including communication, transformation, and energy conduction. The advent of electroluminescent fibers, which emit light in response to an applied electric field, has opened the door for fabric-integrated emissive displays in textiles. This thesis focuses on the development of a flexible and scalable emissive fabric display with individually addressable pixels disposed within a fabric matrix. The pixels are formed in areas where a fiber supporting the dielectric and phosphor layers of an electroluminescent structure contacts a conductive surface. This conductive surface can be an external conductive fiber, yarn or wire, or a translucent conductive material layer deposited at set points along the electroluminescent fibers. Different contacting methods are introduced and the different ways the EL yarns can be incorporated into the knitted fabric are discussed. EL fibers were fabricated using a single yarn coating system with a custom, adjustable 3D printed slot die coater for even distribution of material onto the supporting fiber substrates. These fibers are mechanically characterized inside of and outside of a knitted fabric matrix to determine their potential for various applications, including wearables. A 4-pixel dynamic emissive display prototype is fabricated and characterized. This is the first demonstration of an all-knit emissive display with individually controllable pixels. The prototype is composed of a grid of fibers supporting the dielectric and phosphor layers of an electroluminescent (EL) device structure, called EL fibers, and conductive fibers acting as the top electrode. This grid is integrated into a biaxial weft knit structure where the EL fibers make up the rows and conductive fibers make up the columns of the reinforcement yarns inside the supporting weft knit. The pixels exist as individual segments of electroluminescence that occur where the conductive fibers contact the EL fibers. A passive matrix addressing scheme was used to apply a voltage to each pixel individually, creating a display capable of dynamically communicating information. Optical measurements of the intensity and color of emitted light were used to quantify the performance of the display and compare it to state-of-the-art display technologies. The charge-voltage (Q-V) electrical characterization technique is used to gain information about the ACPEL fiber device operation, and mechanical tests were performed to determine the effect everyday wear and tear would have on the performance of the display. The presented textile display structure and method of producing fibers with individual sections of electroluminescence addresses the shortcomings in existing textile display technology and provides a route to directly integrated communicative textiles for applications ranging from biomedical research and monitoring to fashion. An extensive discussion of the materials and methods of production needed to scale this textile display technology and incorporate it into wearable applications is presented.

Surface display of metal binding domain derived from PbrR on Escherichia coli specifically increases lead(II) adsorption.

PubMed

Hui, Chang-Ye; Guo, Yan; Yang, Xue-Qin; Zhang, Wen; Huang, Xian-Qing

2018-05-01

To improve the Pb 2+ biosorption capacity of the potential E. coli biosorbent, a putative Pb 2+ binding domain (PbBD) derived from PbrR was efficiently displayed on to the E. coli cell surface. The PbBD was obtained by truncating the N-terminal DNA-binding domain and C-terminal redundant amino acid residues of the Pb 2+ -sensing transcriptional factor PbrR. Whole-cell sorbents were constructed with the full-length PbrR and PbBD of PbrR genetically engineered onto the surface of E. coli cells using Lpp-OmpA as the anchor. Followed by a 1.71-fold higher display of PbBD than PbrR, the presence of PbBD on the surface of E. coli cells enabled a 1.92-fold higher Pb 2+ biosorption than that found in PbrR-displayed cells. Specific Pb 2+ binding via PbBD was the same as Pb 2+ binding via the full-length PbrR, with no observable decline even in the presence of Zn 2+ and Cd 2+ . Since surface-engineered E. coli cells with PbBD increased the Pb 2+ binding capacity and did not affect the adsorption selectivity, this suggests that surface display of the metal binding domain derived from MerR-like proteins may be used for the bioremediation of specific toxic heavy metals.

Development of a High-Throughput Flow Cytometry Assay to Monitor Defective Trafficking and Rescue of Long QT2 Mutant hERG Channels

PubMed Central

Kanner, Scott A.; Jain, Ananya; Colecraft, Henry M.

2018-01-01

Long QT Syndrome (LQTS) is an acquired or inherited disorder characterized by prolonged QT interval, exertion-triggered arrhythmias, and sudden cardiac death. One of the most prevalent hereditary LQTS subtypes, LQT2, results from loss-of-function mutations in the hERG channel, which conducts IKr, the rapid component of the delayed rectifier K+ current, critical for cardiac repolarization. The majority of LQT2 mutations result in Class 2 deficits characterized by impaired maturation and trafficking of hERG channels. Here, we have developed a high-throughput flow cytometric assay to analyze the surface and total expression of wild-type (WT) and mutant hERG channels with single-cell resolution. To test our method, we focused on 16 LQT2 mutations in the hERG Per-Arnt-Sim (PAS) domain that were previously studied via a widely used biochemical approach that compares levels of 135-kDa immature and 155-kDa fully glycosylated hERG protein to infer surface expression. We confirmed that LQT2 mutants expressed in HEK293 cells displayed a decreased surface density compared to WT hERG, and were differentially rescued by low temperature. However, we also uncovered some notable differences from the findings obtained via the biochemical approach. In particular, three mutations (N33T, R56Q, and A57P) with apparent WT-like hERG glycosylation patterns displayed up to 50% decreased surface expression. Furthermore, despite WT-like levels of complex glycosylation, these mutants have impaired forward trafficking, and exhibit varying half-lives at the cell surface. The results highlight utility of the surface labeling/flow cytometry approach to quantitatively assess trafficking deficiencies associated with LQT2 mutations, to discern underlying mechanisms, and to report on interventions that rescue deficits in hERG surface expression. PMID:29725305

Single Molecule Analysis of Serotonin Transporter Regulation Using Antagonist-Conjugated Quantum Dots Reveals Restricted, p38 MAPK-Dependent Mobilization Underlying Uptake Activation

PubMed Central

Chang, Jerry C.; Tomlinson, Ian D.; Warnement, Michael R.; Ustione, Alessandro; Carneiro, Ana M. D.; Piston, David W.; Blakely, Randy D.; Rosenthal, Sandra J.

2012-01-01

The presynaptic serotonin (5-HT) transporter (SERT) is targeted by widely prescribed antidepressant medications. Altered SERT expression or regulation has been implicated in multiple neuropsychiatric disorders, including anxiety, depression and autism. Here, we implement a generalizable strategy that exploits antagonist-conjugated quantum dots (Qdots) to monitor, for the first time, single SERT proteins on the surface of serotonergic cells. We document two pools of SERT proteins defined by lateral mobility, one that exhibits relatively free diffusion, and a second, localized to cholesterol and GM1 ganglioside-enriched microdomains, that displays restricted mobility. Receptor-linked signalling pathways that enhance SERT activity mobilize transporters that, nonetheless, remain confined to membrane microdomains. Mobilization of transporters arise from a p38 MAPK-dependent untethering of the SERT C-terminus from the juxtamembrane actin cytoskeleton. Our studies establish the utility of ligand-conjugated Qdots for analysis of the behaviour of single membrane proteins and reveal a physical basis for signaling-mediated SERT regulation. PMID:22745492

Proximity-Based Differential Single-Cell Analysis of the Niche to Identify Stem/Progenitor Cell Regulators.

PubMed

Silberstein, Lev; Goncalves, Kevin A; Kharchenko, Peter V; Turcotte, Raphael; Kfoury, Youmna; Mercier, Francois; Baryawno, Ninib; Severe, Nicolas; Bachand, Jacqueline; Spencer, Joel A; Papazian, Ani; Lee, Dongjun; Chitteti, Brahmananda Reddy; Srour, Edward F; Hoggatt, Jonathan; Tate, Tiffany; Lo Celso, Cristina; Ono, Noriaki; Nutt, Stephen; Heino, Jyrki; Sipilä, Kalle; Shioda, Toshihiro; Osawa, Masatake; Lin, Charles P; Hu, Guo-Fu; Scadden, David T

2016-10-06

Physiological stem cell function is regulated by secreted factors produced by niche cells. In this study, we describe an unbiased approach based on the differential single-cell gene expression analysis of mesenchymal osteolineage cells close to, and further removed from, hematopoietic stem/progenitor cells (HSPCs) to identify candidate niche factors. Mesenchymal cells displayed distinct molecular profiles based on their relative location. We functionally examined, among the genes that were preferentially expressed in proximal cells, three secreted or cell-surface molecules not previously connected to HSPC biology-the secreted RNase angiogenin, the cytokine IL18, and the adhesion molecule Embigin-and discovered that all of these factors are HSPC quiescence regulators. Therefore, our proximity-based differential single-cell approach reveals molecular heterogeneity within niche cells and can be used to identify novel extrinsic stem/progenitor cell regulators. Similar approaches could also be applied to other stem cell/niche pairs to advance the understanding of microenvironmental regulation of stem cell function. Copyright © 2016 Elsevier Inc. All rights reserved.

Single Molecule Analysis of Serotonin Transporter Regulation Using Quantum Dots

NASA Astrophysics Data System (ADS)

Chang, Jerry; Tomlinson, Ian; Warnement, Michael; Ustione, Alessandro; Carneiro, Ana; Piston, David; Blakely, Randy; Rosenthal, Sandra

2011-03-01

For the first time, we implement a novel, single molecule approach to define the localization and mobility of the brain's major target of widely prescribed antidepressant medications, the serotonin transporter (SERT). SERT labeled with single quantum dot (Qdot) revealed unsuspected features of transporter mobility with cholesterol-enriched membrane microdomains (often referred to as ``lipid rafts'') and cytoskeleton network linked to transporter activation. We document two pools of surface SERT proteins defined by their lateral mobility, one that exhibits relatively free diffusion in the plasma membrane and a second that displays significantly restricted mobility and localizes to cholesterol-enriched microdomains. Diffusion model prediction and instantaneous velocity analysis indicated that stimuli that act through p38 MAPK-dependent signaling pathways to activate SERT trigger rapid SERT movements within membrane microdomains. Cytoskeleton disruption showed that SERT lateral mobility behaves a membrane raft-constrained, cytoskeleton-associated manner. Our results identify an unsuspected aspect of neurotransmitter transporter regulation that we propose reflects the dissociation of inhibitory, SERT-associated cytoskeletal anchors.

The Pluto system: Initial results from its exploration by New Horizons

NASA Astrophysics Data System (ADS)

Stern, S. A.; Bagenal, F.; Ennico, K.; Gladstone, G. R.; Grundy, W. M.; McKinnon, W. B.; Moore, J. M.; Olkin, C. B.; Spencer, J. R.; Weaver, H. A.; Young, L. A.; Andert, T.; Andrews, J.; Banks, M.; Bauer, B.; Bauman, J.; Barnouin, O. S.; Bedini, P.; Beisser, K.; Beyer, R. A.; Bhaskaran, S.; Binzel, R. P.; Birath, E.; Bird, M.; Bogan, D. J.; Bowman, A.; Bray, V. J.; Brozovic, M.; Bryan, C.; Buckley, M. R.; Buie, M. W.; Buratti, B. J.; Bushman, S. S.; Calloway, A.; Carcich, B.; Cheng, A. F.; Conard, S.; Conrad, C. A.; Cook, J. C.; Cruikshank, D. P.; Custodio, O. S.; Dalle Ore, C. M.; Deboy, C.; Dischner, Z. J. B.; Dumont, P.; Earle, A. M.; Elliott, H. A.; Ercol, J.; Ernst, C. M.; Finley, T.; Flanigan, S. H.; Fountain, G.; Freeze, M. J.; Greathouse, T.; Green, J. L.; Guo, Y.; Hahn, M.; Hamilton, D. P.; Hamilton, S. A.; Hanley, J.; Harch, A.; Hart, H. M.; Hersman, C. B.; Hill, A.; Hill, M. E.; Hinson, D. P.; Holdridge, M. E.; Horanyi, M.; Howard, A. D.; Howett, C. J. A.; Jackman, C.; Jacobson, R. A.; Jennings, D. E.; Kammer, J. A.; Kang, H. K.; Kaufmann, D. E.; Kollmann, P.; Krimigis, S. M.; Kusnierkiewicz, D.; Lauer, T. R.; Lee, J. E.; Lindstrom, K. L.; Linscott, I. R.; Lisse, C. M.; Lunsford, A. W.; Mallder, V. A.; Martin, N.; McComas, D. J.; McNutt, R. L.; Mehoke, D.; Mehoke, T.; Melin, E. D.; Mutchler, M.; Nelson, D.; Nimmo, F.; Nunez, J. I.; Ocampo, A.; Owen, W. M.; Paetzold, M.; Page, B.; Parker, A. H.; Parker, J. W.; Pelletier, F.; Peterson, J.; Pinkine, N.; Piquette, M.; Porter, S. B.; Protopapa, S.; Redfern, J.; Reitsema, H. J.; Reuter, D. C.; Roberts, J. H.; Robbins, S. J.; Rogers, G.; Rose, D.; Runyon, K.; Retherford, K. D.; Ryschkewitsch, M. G.; Schenk, P.; Schindhelm, E.; Sepan, B.; Showalter, M. R.; Singer, K. N.; Soluri, M.; Stanbridge, D.; Steffl, A. J.; Strobel, D. F.; Stryk, T.; Summers, M. E.; Szalay, J. R.; Tapley, M.; Taylor, A.; Taylor, H.; Throop, H. B.; Tsang, C. C. C.; Tyler, G. L.; Umurhan, O. M.; Verbiscer, A. J.; Versteeg, M. H.; Vincent, M.; Webbert, R.; Weidner, S.; Weigle, G. E.; White, O. L.; Whittenburg, K.; Williams, B. G.; Williams, K.; Williams, S.; Woods, W. W.; Zangari, A. M.; Zirnstein, E.

2015-10-01

The Pluto system was recently explored by NASA’s New Horizons spacecraft, making closest approach on 14 July 2015. Pluto’s surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto’s atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto’s diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto’s large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

Single Particle Dynamic Imaging and Fe3+ Sensing with Bright Carbon Dots Derived from Bovine Serum Albumin Proteins

NASA Astrophysics Data System (ADS)

Yang, Qingxiu; Wei, Lin; Zheng, Xuanfang; Xiao, Lehui

2015-12-01

In this work, we demonstrated a convenient and green strategy for the synthesis of highly luminescent and water-soluble carbon dots (Cdots) by carbonizing carbon precursors, i.e., Bovine serum albumin (BSA) nanoparticles, in water solution. Without post surface modification, the as-synthesized Cdots exhibit fluorescence quantum yield (Q.Y.) as high as 34.8% and display superior colloidal stability not only in concentrated salt solutions (e.g. 2 M KCl) but also in a wide range of pH solutions. According to the FT-IR measurements, the Cdots contain many carboxyl groups, providing a versatile route for further chemical and biological functionalization. Through conjugation of Cdots with the transacting activator of transcription (TAT) peptide (a kind of cell penetration peptide (CPP)) derived from human immunodeficiency virus (HIV), it is possible to directly monitor the dynamic interactions of CPP with living cell membrane at single particle level. Furthermore, these Cdots also exhibit a dosage-dependent selectivity toward Fe3+ among other metal ions, including K+, Na+, Mg2+, Hg2+, Co2+, Cu2+, Pb2+ and Al3+. We believed that the Cdots prepared by this strategy would display promising applications in various areas, including analytical chemistry, nanomedicine, biochemistry and so on.

Effects of combining vertical and horizontal information into a primary flight display

NASA Technical Reports Server (NTRS)

Abbott, Terence S.; Nataupsky, Mark; Steinmetz, George G.

1987-01-01

A ground-based aircraft simulation study was conducted to determine the effects of combining vertical and horizontal flight information into a single display. Two display configurations were used in this study. The first configuration consisted of a Primary Flight Display (PFD) format and a Horizontal Situation Display (HSD) with the PFD displayed conventionally above the HSD. For the second display configuration, the HSD format was combined with the PFD format. Four subjects participated in this study. Data were collected on performance parameters, pilot-control inputs, auditory evoked response parameters (AEP), oculometer measurements (eye-scan), and heart rate. Subjective pilot opinion was gathered through questionnaire data and scorings for both the Subjective Workload Assessment Technique (SWAT) and the NASA Task Load Index (NASA-TLX). The results of this study showed that, from a performance and subjective standpoint, the combined configuration was better than the separate configuration. Additionally, both the eye-transition and eye-dwell times for the separate HSD were notably higher than expected, with a 46% increase in available visual time when going from double to single display configuration.

Digital retrospective motion-mode display and processing of electron beam cine-computed tomography and other cross-sectional cardiac imaging techniques

NASA Astrophysics Data System (ADS)

Reed, Judd E.; Rumberger, John A.; Buithieu, Jean; Behrenbeck, Thomas; Breen, Jerome F.; Sheedy, Patrick F., II

1995-05-01

Electron beam computed tomography is unparalleled in its ability to consistently produce high quality dynamic images of the human heart. Its use in quantification of left ventricular dynamics is well established in both clinical and research applications. However, the image analysis tools supplied with the scanners offer a limited number of analysis options. They are based on embedded computer systems which have not been significantly upgraded since the scanner was introduced over a decade ago in spite of the explosive improvements in available computer power which have occured during this period. To address these shortcomings, a workstation-based ventricular analysis system has been developed at our institution. This system, which has been in use for over five years, is based on current workstation technology and therefore has benefited from the periodic upgrades in processor performance available to these systems. The dynamic image segmentation component of this system is an interactively supervised, semi-automatic surface identification and tracking system. It characterizes the endocardial and epicardial surfaces of the left ventricle as two concentric 4D hyper-space polyhedrons. Each of these polyhedrons have nearly ten thousand vertices which are deposited into a relational database. The right ventricle is also processed in a similar manner. This database is queried by other custom components which extract ventricular function parameters such as regional ejection fraction and wall stress. The interactive tool which supervises dynamic image segmentation has been enhanced with a temporal domain display. The operator interactively chooses the spatial location of the endpoints of a line segment while the corresponding space/time image is displayed. These images, with content resembling M-Mode echocardiography, benefit form electron beam computed tomography's high spatial and contrast resolution. The segmented surfaces are displayed along with the imagery. These displays give the operator valuable feedback pertaining to the contiguity of the extracted surfaces. As with M-Mode echocardiography, the velocity of moving structures can be easily visualized and measured. However, many views inaccessible to standard transthoracic echocardiography are easily generated. These features have augmented the interpretability of cine electron beam computed tomography and have prompted the recent cloning of this system into an 'omni-directional M-Mode display' system for use in digital post-processing of echocardiographic parasternal short axis tomograms. This enhances the functional assessment in orthogonal views of the left ventricle, accounting for shape changes particularly in the asymmetric post-infarction ventricle. Conclusions: A new tool has been developed for analysis and visualization of cine electron beam computed tomography. It has been found to be very useful in verifying the consistency of myocardial surface definition with a semi-automated segmentation tool. By drawing on M-Mode echocardiography experience, electron beam tomography's interpretability has been enhanced. Use of this feature, in conjunction with the existing image processing tools, will enhance the presentations of data on regional systolic and diastolic functions to clinicians in a format that is familiar to most cardiologists. Additionally, this tool reinforces the advantages of electron beam tomography as a single imaging modality for the assessment of left and right ventricular size, shape, and regional functions.

Display of fungal hydrophobin on the Pichia pastoris cell surface and its influence on Candida antarctica lipase B

PubMed Central

Wang, Pan; He, Jie; Sun, Yufei; Reynolds, Matthew; Zhang, Li; Han, Shuangyan; Liang, Shuli; Sui, Haixin; Lin, Ying

2016-01-01

To modify the Pichia pastoris cell surface, two classes of hydrophobins, SC3 from Schizophyllum commune and HFBI from Trichoderma reesei, were separately displayed on the cell wall. There was an observable increase in the hydrophobicity of recombinant strains. Candida antarctica lipase B (CALB) was then co-displayed on the modified cells, generating strains GS115/SC3-61/CALB-51 and GS115/HFBI-61/CALB-51. Interestingly, the hydrolytic and synthetic activities of strain GS115/HFBI-61/CALB-51 increased by 37% and 109%, respectively, but decreased by 26% and 43%, respectively, in strain GS115/SC3-61/CALB-51 compared with the hydrophobin-minus recombinant strain GS115/CALB-GCW51. The amount of glycerol by-product from the transesterification reaction adsorbed on the cell surface was significantly decreased following hydrophobin modification, removing the glycerol barrier and allowing substrates to access the active sites of lipases. Electron micrographs indicated that the cell wall structures of both recombinant strains appeared altered, including changes to the inner glucan layer and outer mannan layer. These results suggest that the display of hydrophobins can change the surface structure and hydrophobic properties of P. pastoris, and affect the catalytic activities of CALB displayed on the surface of P. pastoris cells. PMID:26969039

Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian

PubMed Central

Yin, Zongjun; Zhu, Maoyan; Davidson, Eric H.; Bottjer, David J.; Zhao, Fangchen; Tafforeau, Paul

2015-01-01

An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens. PMID:25775601

Prism-based single-camera system for stereo display

NASA Astrophysics Data System (ADS)

Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

2016-06-01

This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

Crystal structure of the anti-(carcinoembryonic antigen) single-chain Fv antibody MFE-23 and a model for antigen binding based on intermolecular contacts.

PubMed

Boehm, M K; Corper, A L; Wan, T; Sohi, M K; Sutton, B J; Thornton, J D; Keep, P A; Chester, K A; Begent, R H; Perkins, S J

2000-03-01

MFE-23 is the first single-chain Fv antibody molecule to be used in patients and is used to target colorectal cancer through its high affinity for carcinoembryonic antigen (CEA), a cell-surface member of the immunoglobulin superfamily. MFE-23 contains an N-terminal variable heavy-chain domain joined by a (Gly(4)Ser)(3) linker to a variable light-chain (V(L)) domain (kappa chain) with an 11-residue C-terminal Myc-tag. Its crystal structure was determined at 2.4 A resolution by molecular replacement with an R(cryst) of 19.0%. Five of the six antigen-binding loops, L1, L2, L3, H1 and H2, conformed to known canonical structures. The sixth loop, H3, displayed a unique structure, with a beta-hairpin loop and a bifurcated apex characterized by a buried Thr residue. In the crystal lattice, two MFE-23 molecules were associated back-to-back in a manner not seen before. The antigen-binding site displayed a large acidic region located mainly within the H2 loop and a large hydrophobic region within the H3 loop. Even though this structure is unliganded within the crystal, there is an unusually large region of contact between the H1, H2 and H3 loops and the beta-sheet of the V(L) domain of an adjacent molecule (strands DEBA) as a result of intermolecular packing. These interactions exhibited remarkably high surface and electrostatic complementarity. Of seven MFE-23 residues predicted to make contact with antigen, five participated in these lattice contacts, and this model for antigen binding is consistent with previously reported site-specific mutagenesis of MFE-23 and its effect on CEA binding.

Advanced Three-Dimensional Display System

NASA Technical Reports Server (NTRS)

Geng, Jason

2005-01-01

A desktop-scale, computer-controlled display system, initially developed for NASA and now known as the VolumeViewer(TradeMark), generates three-dimensional (3D) images of 3D objects in a display volume. This system differs fundamentally from stereoscopic and holographic display systems: The images generated by this system are truly 3D in that they can be viewed from almost any angle, without the aid of special eyeglasses. It is possible to walk around the system while gazing at its display volume to see a displayed object from a changing perspective, and multiple observers standing at different positions around the display can view the object simultaneously from their individual perspectives, as though the displayed object were a real 3D object. At the time of writing this article, only partial information on the design and principle of operation of the system was available. It is known that the system includes a high-speed, silicon-backplane, ferroelectric-liquid-crystal spatial light modulator (SLM), multiple high-power lasers for projecting images in multiple colors, a rotating helix that serves as a moving screen for displaying voxels [volume cells or volume elements, in analogy to pixels (picture cells or picture elements) in two-dimensional (2D) images], and a host computer. The rotating helix and its motor drive are the only moving parts. Under control by the host computer, a stream of 2D image patterns is generated on the SLM and projected through optics onto the surface of the rotating helix. The system utilizes a parallel pixel/voxel-addressing scheme: All the pixels of the 2D pattern on the SLM are addressed simultaneously by laser beams. This parallel addressing scheme overcomes the difficulty of achieving both high resolution and a high frame rate in a raster scanning or serial addressing scheme. It has been reported that the structure of the system is simple and easy to build, that the optical design and alignment are not difficult, and that the system can be built by use of commercial off-the-shelf products. A prototype of the system displays an image of 1,024 by 768 by 170 (=133,693,440) voxels. In future designs, the resolution could be increased. The maximum number of voxels that can be generated depends upon the spatial resolution of SLM and the speed of rotation of the helix. For example, one could use an available SLM that has 1,024 by 1,024 pixels. Incidentally, this SLM is capable of operation at a switching speed of 300,000 frames per second. Implementation of full-color displays in future versions of the system would be straightforward: One could use three SLMs for red, green, and blue, respectively, and the colors of the voxels could be automatically controlled. An optically simpler alternative would be to use a single red/green/ blue light projector and synchronize the projection of each color with the generation of patterns for that color on a single SLM.

Growth Texture and Mechanism of Zinc Nanowires Produced by Mechanical Elongation of Nanocontacts.

PubMed

Yamabe, Kammu; Kizuka, Tokushi

2018-01-01

Two zinc nanotips were brought into contact and elongated inside a transmission electron microscope, thereby growing single-crystal nanowires. The growth dynamics was observed in situ via a lattice imaging method. The preferential crystal growth directions were identified as [101-0], [112-0], [101-2-], and [0001]. Of these, the nanowires grown along the [101-0] and [112-0] directions accounted for 75% of the total and were surrounded by low-energy side surfaces, i.e., {0001}, {101-1}, and {101-0}. On the basis of these features, models of the nanowire morphology were proposed. In either growth direction, the tensile force aligned parallel to the direction along which slip events corresponding to the predominant slip system were unlikely to occur. This led to a high tensile stress for extracting atoms from the growth region, i.e., the promotion of nanowire growth.

Vacuum-deposited, nonpolymeric flexible organic light-emitting devices.

PubMed

Gu, G; Burrows, P E; Venkatesh, S; Forrest, S R; Thompson, M E

1997-02-01

We demonstrate mechanically flexible, organic light-emitting devices (OLED's) based on the nonpolymetric thin-film materials tris-(8-hydroxyquinoline) aluminum (Alq(3)) and N, N(?) -diphenyl- N, N(?) -bis(3-methylphenyl)1- 1(?) biphenyl-4, 4(?) diamine (TPD). The single heterostructure is vacuum deposited upon a transparent, lightweight, thin plastic substrate precoated with a transparent, conducting indium tin oxide thin film. The flexible OLED performance is comparable with that of conventional OLED's deposited upon glass substrates and does not deteriorate after repeated bending. The large-area (~1 - cm>(2)) devices can be bent without failure even after a permanent fold occurs if they are on the convex substrate surface or over a bend radius of ~0.5>cm if they are on the concave surface. Such devices are useful for ultralightweight, flexible, and comfortable full-color flat panel displays.

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

NASA Astrophysics Data System (ADS)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Bacterial surface-displayed GII.4 human norovirus capsid proteins bound to surface of Romaine lettuce through HBGA-like molecules

USDA-ARS?s Scientific Manuscript database

Human Noroviruses (HuNoVs) are the main cause of nonbacterial gastroenteritis. Contaminated produce is a main vehicle for dissemination of HuNoVs. In this study, we used an ice nucleation protein (INP) mediated surface display system to present the protruding domain of GII.4 HuNoV capsid protein (G...

A comparison study of adsorption of benzohydroxamic acid and amyl xanthate on smithsonite with dodecylamine as co-collector

NASA Astrophysics Data System (ADS)

Wang, Zhen; Xu, Longhua; Wang, Jinming; Wang, Li; Xiao, Junhui

2017-12-01

The objective of this paper is to display the results of the flotation and adsorption behaviors of benzohydroxamic acid (BHA), potassium amyl xanthate (KAX), dodecylamine- hydrochloride (DDA), mixed BHA/DDA and KAX/DDA on smithsonite. The flotation results show a collecting ability sequence of BHA > KAX > DDA on smithsonite and the best flotation performance at mixing ratio of 1:4 mol fraction DDA/KAX for mixed collector on smithsonite. The enhancement of smithsonite recovery by co-adsorption of KAX and DDA, while no promotion effect as to mixed BHA/DDA catanionic system, are attributed to the difference in steric effect of absorbed head group. According to the results of zeta potential and contact angle (CA) measurements, a most negative charged and the highest hydrophobic smithsonite surface are attained using KAX with DDA as co-collector, which shows a good agreement with the flotation results. FTIR measurements display the stabilization against oxidation and decomposition of DDA on KAX and the inhibition of preferential adsorbed BHA ions on DDA adsorption. The interaction energies of single and mixed collectors with mineral surface also shows well consistency with experimental results. The adsorption models proposed illustrate the decrease in the electrostatic head-head repulsion and the increase in lateral tail-tail hydrophobic interaction between adjacent KAX anions due to the insertion of DDA cations, while almost no DDA could access to smithsonite surface through adjacent BHA owing to steric effect.

Engineering M13 for phage display.

PubMed

Sidhu, S S

2001-09-01

Phage display is achieved by fusing polypeptide libraries to phage coat proteins. The resulting phage particles display the polypeptides on their surfaces and they also contain the encoding DNA. Library members with particular functions can be isolated with simple selections and polypeptide sequences can be decoded from the encapsulated DNA. The technology's success depends on the efficiency with which polypeptides can be displayed on the phage surface, and significant progress has been made in engineering M13 bacteriophage coat proteins as improved phage display platforms. Functional display has been achieved with all five M13 coat proteins, with both N- and C-terminal fusions. Also, coat protein mutants have been designed and selected to improve the efficiency of heterologous protein display, and in the extreme case, completely artificial coat proteins have been evolved specifically as display platforms. These studies demonstrate that the M13 phage coat is extremely malleable, and this property can be used to engineer the phage particle specifically for phage display. These improvements expand the utility of phage display as a powerful tool in modern biotechnology.

Modelling and analysis of the wetting characteristics of ink for display applications with the surface evolution technique

NASA Astrophysics Data System (ADS)

Shin, Dong-Youn; Brakke, Kenneth A.

2009-06-01

Piezo drop-on-demand inkjet printing technology has attracted the attention of display industries for the production of colour filters for thin film transistor liquid crystal displays (TFT LCD) because of the opportunity of reducing manufacturing cost. Colourant ink droplets ejected from inkjet nozzles selectively fill subpixels surrounded with black matrix (BM). Surface energy differences between the glass substrate and the BM generally guide this ink filling process. This colourant ink filling process, however, results from the complex hydrodynamic interaction of ink with the substrate and the BM. Neither computationally expensive numerical methods nor time and cost expensive experiments are suitable for the derivation of optimum surface conditions at the early development stage. In this study, a more concise surface evolution technique is proposed and ways to find the optimum surface conditions for the fabrication of TFT LCD colour filters and polymer light emitting devices are discussed, which might be useful for chemists and developers of ink and BM material, as well as for process engineers in display industries.

Research and Development of Large Area Color AC Plasma Displays

NASA Astrophysics Data System (ADS)

Shinoda, Tsutae

1998-10-01

Plasma display is essentially a gas discharge device using discharges in small cavities about 0. 1 m. The color plasma displays utilize the visible light from phosphors excited by the ultra-violet by discharge in contrast to monochrome plasma displays utilizing visible light directly from gas discharges. At the early stage of the color plasma display development, the degradation of the phosphors and unstable operating voltage prevented to realize a practical color plasma display. The introduction of the three-electrode surface-discharge technology opened the way to solve the problems. Two key technologies of a simple panel structure with a stripe rib and phosphor alignment and a full color image driving method with an address-and-display-period-separated sub-field method have realized practically available full color plasma displays. A full color plasma display has been firstly developed in 1992 with a 21-in.-diagonal PDP and then a 42-in.-diagonal PDP in 1995 Currently a 50-in.-diagonal color plasma display has been developed. The large area color plasma displays have already been put into the market and are creating new markets, such as a wall hanging TV and multimedia displays for advertisement, information, etc. This paper will show the history of the surface-discharge color plasma display technologies and current status of the color plasma display.

A photophoretic-trap volumetric display

NASA Astrophysics Data System (ADS)

Smalley, D. E.; Nygaard, E.; Squire, K.; van Wagoner, J.; Rasmussen, J.; Gneiting, S.; Qaderi, K.; Goodsell, J.; Rogers, W.; Lindsey, M.; Costner, K.; Monk, A.; Pearson, M.; Haymore, B.; Peatross, J.

2018-01-01

Free-space volumetric displays, or displays that create luminous image points in space, are the technology that most closely resembles the three-dimensional displays of popular fiction. Such displays are capable of producing images in ‘thin air’ that are visible from almost any direction and are not subject to clipping. Clipping restricts the utility of all three-dimensional displays that modulate light at a two-dimensional surface with an edge boundary; these include holographic displays, nanophotonic arrays, plasmonic displays, lenticular or lenslet displays and all technologies in which the light scattering surface and the image point are physically separate. Here we present a free-space volumetric display based on photophoretic optical trapping that produces full-colour graphics in free space with ten-micrometre image points using persistence of vision. This display works by first isolating a cellulose particle in a photophoretic trap created by spherical and astigmatic aberrations. The trap and particle are then scanned through a display volume while being illuminated with red, green and blue light. The result is a three-dimensional image in free space with a large colour gamut, fine detail and low apparent speckle. This platform, named the Optical Trap Display, is capable of producing image geometries that are currently unobtainable with holographic and light-field technologies, such as long-throw projections, tall sandtables and ‘wrap-around’ displays.

ABI domain containing proteins contribute to surface protein display and cell division in Staphylococcus aureus

PubMed Central

Frankel, Matthew B.; Wojcik, Brandon; DeDent, Andrea C.; Missiakas, Dominique M.; Schneewind, Olaf

2012-01-01

Summary The human pathogen Staphyloccocus aureus requires cell wall anchored surface proteins to cause disease. During cell division, surface proteins with YSIRK signal peptides are secreted into the cross wall, a layer of newly synthesized peptidoglycan between separating daughter cells. The molecular determinants for the trafficking of surface proteins are, however, still unknown. We screened mutants with non-redundant transposon insertions by fluorescence-activated cell sorting for reduced deposition of protein A (SpA) into the staphylococcal envelope. Three mutants, each of which harbored transposon insertions in genes for transmembrane proteins, displayed greatly reduced envelope abundance of SpA and surface proteins with YSIRK signal peptides. Characterization of the corresponding mutations identified three transmembrane proteins with abortive infectivity (ABI) domains, elements first described in lactococci for their role in phage exclusion. Mutations in genes for ABI domain proteins, designated spdA, spdB and spdC (surface protein display), diminish the expression of surface proteins with YSIRK signal peptides, but not of precursor proteins with conventional signal peptides. spdA, spdB and spdC mutants display an increase in the thickness of cross walls and in the relative abundance of staphylococci with cross walls, suggesting that spd mutations may represent a possible link between staphylococcal cell division and protein secretion. PMID:20923422

ABI domain-containing proteins contribute to surface protein display and cell division in Staphylococcus aureus.

PubMed

Frankel, Matthew B; Wojcik, Brandon M; DeDent, Andrea C; Missiakas, Dominique M; Schneewind, Olaf

2010-10-01

The human pathogen Staphylococcus aureus requires cell wall anchored surface proteins to cause disease. During cell division, surface proteins with YSIRK signal peptides are secreted into the cross-wall, a layer of newly synthesized peptidoglycan between separating daughter cells. The molecular determinants for the trafficking of surface proteins are, however, still unknown. We screened mutants with non-redundant transposon insertions by fluorescence-activated cell sorting for reduced deposition of protein A (SpA) into the staphylococcal envelope. Three mutants, each of which harboured transposon insertions in genes for transmembrane proteins, displayed greatly reduced envelope abundance of SpA and surface proteins with YSIRK signal peptides. Characterization of the corresponding mutations identified three transmembrane proteins with abortive infectivity (ABI) domains, elements first described in lactococci for their role in phage exclusion. Mutations in genes for ABI domain proteins, designated spdA, spdB and spdC (surface protein display), diminish the expression of surface proteins with YSIRK signal peptides, but not of precursor proteins with conventional signal peptides. spdA, spdB and spdC mutants display an increase in the thickness of cross-walls and in the relative abundance of staphylococci with cross-walls, suggesting that spd mutations may represent a possible link between staphylococcal cell division and protein secretion. © 2010 Blackwell Publishing Ltd.

3-D surface reconstruction of patient specific anatomic data using a pre-specified number of polygons.

PubMed

Aharon, S; Robb, R A

1997-01-01

Virtual reality environments provide highly interactive, natural control of the visualization process, significantly enhancing the scientific value of the data produced by medical imaging systems. Due to the computational and real time display update requirements of virtual reality interfaces, however, the complexity of organ and tissue surfaces which can be displayed is limited. In this paper, we present a new algorithm for the production of a polygonal surface containing a pre-specified number of polygons from patient or subject specific volumetric image data. The advantage of this new algorithm is that it effectively tiles complex structures with a specified number of polygons selected to optimize the trade-off between surface detail and real-time display rates.

Peripheral vision horizon display on the single seat night attack A-10

NASA Technical Reports Server (NTRS)

Nims, D. F.

1984-01-01

The concept of the peripheral vision horizon display (PVHD) held promise for significant reduction in workload for the single seat night attack pilot. For this reason it was incorporated in the single seat night attack (SSNA) A-10. The implementation and results of the PVHD on the SSNA A-10 are discussed as well as the SSNA program. The part the PVHD played in the test and the results and conclusions of that effort are also considered.

The Pluto system: Initial results from its exploration by New Horizons.

PubMed

Stern, S A; Bagenal, F; Ennico, K; Gladstone, G R; Grundy, W M; McKinnon, W B; Moore, J M; Olkin, C B; Spencer, J R; Weaver, H A; Young, L A; Andert, T; Andrews, J; Banks, M; Bauer, B; Bauman, J; Barnouin, O S; Bedini, P; Beisser, K; Beyer, R A; Bhaskaran, S; Binzel, R P; Birath, E; Bird, M; Bogan, D J; Bowman, A; Bray, V J; Brozovic, M; Bryan, C; Buckley, M R; Buie, M W; Buratti, B J; Bushman, S S; Calloway, A; Carcich, B; Cheng, A F; Conard, S; Conrad, C A; Cook, J C; Cruikshank, D P; Custodio, O S; Dalle Ore, C M; Deboy, C; Dischner, Z J B; Dumont, P; Earle, A M; Elliott, H A; Ercol, J; Ernst, C M; Finley, T; Flanigan, S H; Fountain, G; Freeze, M J; Greathouse, T; Green, J L; Guo, Y; Hahn, M; Hamilton, D P; Hamilton, S A; Hanley, J; Harch, A; Hart, H M; Hersman, C B; Hill, A; Hill, M E; Hinson, D P; Holdridge, M E; Horanyi, M; Howard, A D; Howett, C J A; Jackman, C; Jacobson, R A; Jennings, D E; Kammer, J A; Kang, H K; Kaufmann, D E; Kollmann, P; Krimigis, S M; Kusnierkiewicz, D; Lauer, T R; Lee, J E; Lindstrom, K L; Linscott, I R; Lisse, C M; Lunsford, A W; Mallder, V A; Martin, N; McComas, D J; McNutt, R L; Mehoke, D; Mehoke, T; Melin, E D; Mutchler, M; Nelson, D; Nimmo, F; Nunez, J I; Ocampo, A; Owen, W M; Paetzold, M; Page, B; Parker, A H; Parker, J W; Pelletier, F; Peterson, J; Pinkine, N; Piquette, M; Porter, S B; Protopapa, S; Redfern, J; Reitsema, H J; Reuter, D C; Roberts, J H; Robbins, S J; Rogers, G; Rose, D; Runyon, K; Retherford, K D; Ryschkewitsch, M G; Schenk, P; Schindhelm, E; Sepan, B; Showalter, M R; Singer, K N; Soluri, M; Stanbridge, D; Steffl, A J; Strobel, D F; Stryk, T; Summers, M E; Szalay, J R; Tapley, M; Taylor, A; Taylor, H; Throop, H B; Tsang, C C C; Tyler, G L; Umurhan, O M; Verbiscer, A J; Versteeg, M H; Vincent, M; Webbert, R; Weidner, S; Weigle, G E; White, O L; Whittenburg, K; Williams, B G; Williams, K; Williams, S; Woods, W W; Zangari, A M; Zirnstein, E

2015-10-16

The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected. Copyright © 2015, American Association for the Advancement of Science.

Surface Textures and Features Indicative of Endogenous Growth at the McCartys Flow Field, NM, as an Analog to Martian Volcanic Plains

NASA Technical Reports Server (NTRS)

Bleacher, Jacob E.; Crumpler, L. S.; Garry, W. B.; Zimbelman, J. R.; Self, S.; Aubele, J. C.

2012-01-01

Basaltic lavas typically form channels or tubes, which are recognized on the Earth and Mars. Although largely unrecognized in the planetary community, terrestrial inflated sheet flows also display morphologies that share many commonalities with lava plains on Mars. The McCartys lava flow field is among the youngest (approx.3000 yrs) basaltic flows in the continental United States. The southwest sections of the flow displays smooth, flat-topped plateaus with irregularly shaped pits and hummocky inter-plateau units that form a polygonal surface. Plateaus are typically elongate in map view, up to 20 m high and display lineations within the glassy crust. Lineated surfaces occasionally display small < 1m diameter lava coils. Lineations are generally straight and parallel each other, sometimes for over 100 meters. The boundaries between plateaus and depressions are also lineated and tilted to angles sometimes approaching vertical. Plateau-parallel cracks, sometimes containing squeeze-ups, mark the boundary between tilted crust and plateau. Some plateau depressions display level floors with hummocky surfaces, while some are bowl shaped with floors covered in broken lava slabs. The lower walls of pits sometimes display lateral, sagged lava wedges. Infrequently, pit floors display the upper portion of a tumulus from an older flow. In some places the surface crust has been disrupted forming a slabby texture. Slabs are typically on the scale of a meter or less across and no less than 7-10 cm thick. The slabs preserve the lineated textures of the undisturbed plateau crust. It appears that this style of terrain represents the emplacement of an extensive sheet that experiences inflation episodes within preferred regions where lateral spreading of the sheet is inhibited, thereby forming plateaus. Rough surfaces represent inflation-related disruption of pahoehoe lava and not a a lava. Depressions are often the result of non-inflation and can be clearly identified by lateral squeeze-outs along the pit walls that form when the rising crust exposes the still liquid core of the sheet. The plains of Tharsis and Elysium, Mars, display many analogous features

General facile approach to transition-metal oxides with highly uniform mesoporosity and their application as adsorbents for heavy-metal-ion sequestration.

PubMed

Seisenbaeva, Gulaim A; Daniel, Geoffrey; Kessler, Vadim G; Nedelec, Jean-Marie

2014-08-18

Mesoporous powders of transition-metal oxides, TiO2, ZrO2, HfO2, Nb2O5, and Ta2O5, pure from organic impurities were produced by a rapid single-step thermohydrolytic approach. The obtained materials display an impressively large active surface area and sharp pore-size distribution, being composed of partially coalesced uniform nanoparticles with crystalline cores and amorphous shells. They reveal extremely high adsorption capacity in removal of Cr(VI) anions from solutions (25.8 for TiO2, 73.0 for ZrO2, and 74.7 mg g(-1) for Nb2O5 in relation to the Cr2O7(2-) anion), making them very attractive as adsorbents in water remediation applications. The difference in adsorption capacities for the studied oxides may be explained by variation in surface hydration and surface-charge distribution. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concurrent detection of secreted products from human lymphocytes by microengraving: cytokines and antigen-reactive antibodies

PubMed Central

Bradshaw, Elizabeth M.; Kent, Sally C.; Tripuraneni, Vinay; Orban, Tihamer; Ploegh, Hidde L.; Hafler, David A.; Love, J. Christopher

2008-01-01

Cell surface determinants, cytokines and antibodies secreted by hematopoietic cells are used to classify their lineage and function. Currently available techniques are unable to elucidate multiple secreted proteins while also assigning phenotypic surface-displayed markers to the individual living cells. Here, a soft lithographic method, microengraving, was adapted for the multiplexed interrogation of populations of individual human peripheral blood mononuclear cells for secreted cytokines (IFN-γ and IL-6), antigen-specific antibodies, and lineage-specific surface-expressed markers. Application of the method to a clinical sample from a recent onset Type 1 diabetic subject with a positive titer of anti-insulin antibodies showed that ~0.58% of circulating CD19+ B cells secreted proinsulin-reactive antibodies of the IgG isotype and 2–3% of circulating cells secreted IL-6. These data demonstrate the utility of microengraving for interrogating multiple phenotypes of single human cells concurrently and for detecting rare populations of cells by their secreted products. PMID:18675591

Shubnikov-de Haas quantum oscillations reveal a reconstructed Fermi surface near optimal doping in a thin film of the cuprate superconductor Pr 1.86 Ce 0.14 CuO 4 ± δ

DOE PAGES

Breznay, Nicholas P.; Hayes, Ian M.; Ramshaw, B. J.; ...

2016-09-16

In this work, we study magnetotransport properties of the electron-doped superconductor Pr 2-xCe xCuO 4±δ with x = 0.14 in magnetic fields up to 92 T, and observe Shubnikov-de Haas magnetic quantum oscillations. The oscillations display a single frequency F = 255 ± 10 T, indicating a small Fermi pocket that is ~1 % of the two-dimensional Brillouin zone and consistent with a Fermi surface reconstructed from the large holelike cylinder predicted for these layered materials. Despite the low nominal doping, all electronic properties including the effective mass and Hall effect are consistent with overdoped compounds. In conclusion, our studymore » demonstrates that the exceptional chemical control afforded by high quality thin films will enable Fermi surface studies deep into the overdoped cuprate phase diagram.« less

Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

DOE PAGES

Novotny, Z.; Netzer, F. P.; Dohnalek, Z.

2016-03-22

In this study, the growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO 2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. Themore » ceria clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures > 450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters.« less

The contribution of cutaneous and kinesthetic sensory modalities in haptic perception of orientation.

PubMed

Frisoli, Antonio; Solazzi, Massimiliano; Reiner, Miriam; Bergamasco, Massimo

2011-06-30

The aim of this study was to understand the integration of cutaneous and kinesthetic sensory modalities in haptic perception of shape orientation. A specific robotic apparatus was employed to simulate the exploration of virtual surfaces by active touch with two fingers, with kinesthetic only, cutaneous only and combined sensory feedback. The cutaneous feedback was capable of displaying the local surface orientation at the contact point, through a small plate indenting the fingerpad at contact. A psychophysics test was conducted with SDT methodology on 6 subjects to assess the discrimination threshold of angle perception between two parallel surfaces, with three sensory modalities and two shape sizes. Results show that the cutaneous sensor modality is not affected by size of shape, but kinesthetic performance is decreasing with smaller size. Cutaneous and kinesthetic sensory cues are integrated according to a Bayesian model, so that the combined sensory stimulation always performs better than single modalities alone. Copyright © 2010 Elsevier Inc. All rights reserved.

Controlling the Surface Chemistry of Graphite by Engineered Self-Assembled Peptides

PubMed Central

Khatayevich, Dmitriy; So, Christopher R.; Hayamizu, Yuhei; Gresswell, Carolyn; Sarikaya, Mehmet

2012-01-01

The systematic control over surface chemistry is a long-standing challenge in biomedical and nanotechnological applications for graphitic materials. As a novel approach, we utilize graphite-binding dodecapeptides that self-assemble into dense domains to form monolayer thick long-range ordered films on graphite. Specifically, the peptides are rationally designed through their amino acid sequences to predictably display hydrophilic and hydrophobic characteristics while maintaining their self-assembly capabilities on the solid substrate. The peptides are observed to maintain a high tolerance for sequence modification, allowing the control over surface chemistry via their amino acid sequence. Furthermore, through a single step co-assembly of two different designed peptides, we predictably and precisely tune the wettability of the resulting functionalized graphite surfaces from 44 to 83 degrees. The modular molecular structures and predictable behavior of short peptides demonstrated here give rise to a novel platform for functionalizing graphitic materials that offers numerous advantages, including non-invasive modification of the substrate, bio-compatible processing in an aqueous environment, and simple fusion with other functional biological molecules. PMID:22428620

Simultaneous bioremediation and biodetection of mercury ion through surface display of carboxylesterase E2 from Pseudomonas aeruginosa PA1.

PubMed

Yin, Kun; Lv, Min; Wang, Qiaoning; Wu, Yixuan; Liao, Chunyang; Zhang, Weiwei; Chen, Lingxin

2016-10-15

Mercury is a toxic heavy metal and presents significant threats to organisms and natural ecosystems. Recently, the mercury remediation as well as its detection by environmental-friendly biotechnology has received increasing attention. In this study, carboxylesterase E2 from mercury-resistant strain Pseudomonas aeruginosa PA1 has been successfully displayed on the outer membrane of Escherichia coli Top10 bacteria to simultaneously adsorb and detect mercury ion (Hg(2+)). The transmission electron microscopy analysis shows that Hg(2+) can be absorbed by carboxylesterase E2 and accumulated on the outer membrane of surface-displayed E. coli bacteria. The adsorption of Hg(2+) followed a physicochemical, equilibrated and saturatable mechanism, which well fits the traditional Langmuir adsorption model. The surface-displayed system can be regenerated through regulating pH values. As its activity can be inhibited by Hg(2+), carboxylesterase E2 has been used to detect the concentration of Hg(2+) in water samples. The developed surface display system will be of great potential in the simultaneous bioremediation and biodetection of environmental mercury pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optical characterization of display screens by speckle patterns

NASA Astrophysics Data System (ADS)

Pozo, Antonio M.; Castro, José J.; Rubiño, Manuel

2013-10-01

In recent years, flat-panel display (FPD) technology has undergone great development, and now FPDs appear in many devices. A significant element in FPD manufacturing is the display front surface. Manufacturers sell FPDs with different types of front surfaces, which can be matte (also called anti-glare) or glossy screens. Users who prefer glossy screens consider these displays to show more vivid colors compared with matte-screen displays. However, on the glossy screens, external light sources may cause unpleasant reflections that can be reduced by a matte treatment in the front surface. In this work, we present a method to characterize FPD screens using laser-speckle patterns. We characterize three FPDs: a Samsung XL2370 LCD monitor of 23 in. with matte screen, a Toshiba Satellite A100 LCD laptop of 15.4 in. with glossy screen, and a Grammata Papyre 6.1 electronic book reader of 6 in. with ePaper screen (E-ink technology). The results show great differences in speckle-contrast values for the three screens characterized and, therefore, this work shows the feasibility of this method for characterizing and comparing FPDs that have different types of front surfaces.

Automatic detection method for mura defects on display film surface using modified Weber's law

NASA Astrophysics Data System (ADS)

Kim, Myung-Muk; Lee, Seung-Ho

2014-07-01

We propose a method that automatically detects mura defects on display film surfaces using a modified version of Weber's law. The proposed method detects mura defects regardless of their properties and shapes by identifying regions perceived by human vision as mura using the brightness of pixel and image distribution ratio of mura in an image histogram. The proposed detection method comprises five stages. In the first stage, the display film surface image is acquired and a gray-level shift performed. In the second and third stages, the image histogram is acquired and analyzed, respectively. In the fourth stage, the mura range is acquired. This is followed by postprocessing in the fifth stage. Evaluations of the proposed method conducted using 200 display film mura image samples indicate a maximum detection rate of ˜95.5%. Further, the results of application of the Semu index for luminance mura in flat panel display (FPD) image quality inspection indicate that the proposed method is more reliable than a popular conventional method.

The use of computer-generated color graphic images for transient thermal analysis. [for hypersonic aircraft

NASA Technical Reports Server (NTRS)

Edwards, C. L. W.; Meissner, F. T.; Hall, J. B.

1979-01-01

Color computer graphics techniques were investigated as a means of rapidly scanning and interpreting large sets of transient heating data. The data presented were generated to support the conceptual design of a heat-sink thermal protection system (TPS) for a hypersonic research airplane. Color-coded vector and raster displays of the numerical geometry used in the heating calculations were employed to analyze skin thicknesses and surface temperatures of the heat-sink TPS under a variety of trajectory flight profiles. Both vector and raster displays proved to be effective means for rapidly identifying heat-sink mass concentrations, regions of high heating, and potentially adverse thermal gradients. The color-coded (raster) surface displays are a very efficient means for displaying surface-temperature and heating histories, and thereby the more stringent design requirements can quickly be identified. The related hardware and software developments required to implement both the vector and the raster displays for this application are also discussed.

Human Enterovirus 71 Protein Displayed on the Surface of Saccharomyces cerevisiae as an Oral Vaccine.

PubMed

Zhang, Congdang; Wang, Yi; Ma, Shuzhi; Li, Leike; Chen, Liyun; Yan, Huimin; Peng, Tao

2016-06-01

Human enterovirus 71 (EV-A71), a major agent of hand, foot, and mouth disease, has become an important public health issue in recent years. No effective antiviral or vaccines against EV-A71 infection are currently available. EV-A71 infection intrudes bodies through the gastric mucosal surface and it is necessary to enhance mucosal immune response to protect children from these pathogens. Recently, the majority of EV-A71 vaccine candidates have been developed for parenteral immunization. However, parenteral vaccine candidates often induce poor mucosal responses. On the other hand, oral vaccines could induce effective mucosal and systemic immunity, and could be easily and safely administered. Thus, proper oral vaccines have attached more interest compared with parenteral vaccine. In this study, the major immunogenic capsid protein of EV-A71 was displayed on the surface of Saccharomyces cerevisiae. Oral immunization of mice with surface-displayed VP1 S. cerevisiae induced systemic humoral and mucosal immune responses, including virus-neutralizing titers, VP1-specific antibody, and the induction of Th1 immune responses in the spleen. Furthermore, oral immunization of mother mice with surface-displayed VP1 S. cerevisiae conferred protection to neonatal mice against the lethal EV-A71 infection. Furthermore, we observed that multiple boost immunization as well as higher immunization dosage could induce higher EV-A71-specific immune response. Our results demonstrated that surface-displayed VP1 S. cerevisiae could be used as potential oral vaccine against EV-A71 infection.

Three-dimensional display of cortical anatomy and vasculature: MR angiography versus multimodality integration

NASA Astrophysics Data System (ADS)

Henri, Christopher J.; Pike, Gordon; Collins, D. Louis; Peters, Terence M.

1990-07-01

We present two methods for acquiring and viewing integrated 3-D images of cerebral vasculature and cortical anatomy. The aim of each technique is to provide the neurosurgeon or radiologist with a 3-D image containing information which cannot ordinarily be obtained from a single imaging modality. The first approach employs recent developments in MR which is now capable of imaging flowing blood as well as static tissue. Here, true 3-D data are acquired and displayed using volume or surface rendering techniques. The second approach is based on the integration of x-ray projection angiograms and tomographic image data, allowing a composite image of anatomy and vasculature to be viewed in 3-D. This is accomplished by superimposing an angiographic stereo-pair onto volume rendered images of either CT or MR data created from matched viewing geometries. The two approaches are outlined and compared. Results are presented for each technique and potential clinical applications discussed.

Cephalopod-inspired design of electro-mechano-chemically responsive elastomers for on-demand fluorescent patterning

NASA Astrophysics Data System (ADS)

Wang, Qiming; Gossweiler, Gregory R.; Craig, Stephen L.; Zhao, Xuanhe

2014-09-01

Cephalopods can display dazzling patterns of colours by selectively contracting muscles to reversibly activate chromatophores - pigment-containing cells under their skins. Inspired by this novel colouring strategy found in nature, we design an electro-mechano-chemically responsive elastomer system that can exhibit a wide variety of fluorescent patterns under the control of electric fields. We covalently couple a stretchable elastomer with mechanochromic molecules, which emit strong fluorescent signals if sufficiently deformed. We then use electric fields to induce various patterns of large deformation on the elastomer surface, which displays versatile fluorescent patterns including lines, circles and letters on demand. Theoretical models are further constructed to predict the electrically induced fluorescent patterns and to guide the design of this class of elastomers and devices. The material and method open promising avenues for creating flexible devices in soft/wet environments that combine deformation, colorimetric and fluorescent response with topological and chemical changes in response to a single remote signal.

Spontaneous assembly of chemically encoded two-dimensional coacervate droplet arrays by acoustic wave patterning

PubMed Central

Tian, Liangfei; Martin, Nicolas; Bassindale, Philip G.; Patil, Avinash J.; Li, Mei; Barnes, Adrian; Drinkwater, Bruce W.; Mann, Stephen

2016-01-01

The spontaneous assembly of chemically encoded, molecularly crowded, water-rich micro-droplets into periodic defect-free two-dimensional arrays is achieved in aqueous media by a combination of an acoustic standing wave pressure field and in situ complex coacervation. Acoustically mediated coalescence of primary droplets generates single-droplet per node micro-arrays that exhibit variable surface-attachment properties, spontaneously uptake dyes, enzymes and particles, and display spatial and time-dependent fluorescence outputs when exposed to a reactant diffusion gradient. In addition, coacervate droplet arrays exhibiting dynamical behaviour and exchange of matter are prepared by inhibiting coalescence to produce acoustically trapped lattices of droplet clusters that display fast and reversible changes in shape and spatial configuration in direct response to modulations in the acoustic frequencies and fields. Our results offer a novel route to the design and construction of ‘water-in-water' micro-droplet arrays with controllable spatial organization, programmable signalling pathways and higher order collective behaviour. PMID:27708286

Electricity generation from real industrial wastewater using a single-chamber air cathode microbial fuel cell with an activated carbon anode.

PubMed

Mohamed, Hend Omar; Obaid, M; Sayed, Enas Taha; Liu, Yang; Lee, Jinpyo; Park, Mira; Barakat, Nasser A M; Kim, Hak Yong

2017-08-01

This study introduces activated carbon (AC) as an effective anode for microbial fuel cells (MFCs) using real industrial wastewater without treatment or addition of external microorganism mediators. Inexpensive activated carbon is introduced as a proper electrode alternative to carbon cloth and carbon paper materials, which are considered too expensive for the large-scale application of MFCs. AC has a porous interconnected structure with a high bio-available surface area. The large surface area, in addition to the high macro porosity, facilitates the high performance by reducing electron transfer resistance. Extensive characterization, including surface morphology, material chemistry, surface area, mechanical strength and biofilm adhesion, was conducted to confirm the effectiveness of the AC material as an anode in MFCs. The electrochemical performance of AC was also compared to other anodes, i.e., Teflon-treated carbon cloth (CCT), Teflon-treated carbon paper (CPT), untreated carbon cloth (CC) and untreated carbon paper (CP). Initial tests of a single air-cathode MFC display a current density of 1792 mAm -2 , which is approximately four times greater than the maximum value of the other anode materials. COD analyses and Coulombic efficiency (CE) measurements for AC-MFC show the greatest removal of organic compounds and the highest CE efficiency (60 and 71%, respectively). Overall, this study shows a new economical technique for power generation from real industrial wastewater with no treatment and using inexpensive electrode materials.

One Mouse per Child: Interpersonal Computer for Individual Arithmetic Practice

ERIC Educational Resources Information Center

Alcoholado, C.; Nussbaum, M.; Tagle, A.; Gomez, F.; Denardin, F.; Susaeta, H.; Villalta, M.; Toyama, K.

2012-01-01

Single Display Groupware (SDG) allows multiple people in the same physical space to interact simultaneously over a single communal display through individual input devices that work on the same machine. The aim of this paper is to show how SDG can be used to improve the way resources are used in schools, allowing students to work simultaneously on…

A novel shape-changing haptic table-top display

NASA Astrophysics Data System (ADS)

Wang, Jiabin; Zhao, Lu; Liu, Yue; Wang, Yongtian; Cai, Yi

2018-01-01

A shape-changing table-top display with haptic feedback allows its users to perceive 3D visual and texture displays interactively. Since few existing devices are developed as accurate displays with regulatory haptic feedback, a novel attentive and immersive shape changing mechanical interface (SCMI) consisting of image processing unit and transformation unit was proposed in this paper. In order to support a precise 3D table-top display with an offset of less than 2 mm, a custommade mechanism was developed to form precise surface and regulate the feedback force. The proposed image processing unit was capable of extracting texture data from 2D picture for rendering shape-changing surface and realizing 3D modeling. The preliminary evaluation result proved the feasibility of the proposed system.

Design and construction of glutamine binding proteins with a self-adhering capability to unmodified hydrophobic surfaces as reagentless fluorescence sensing devices.

PubMed

Wada, Akira; Mie, Masayasu; Aizawa, Masuo; Lahoud, Pedro; Cass, Anthony E G; Kobatake, Eiry

2003-12-31

The chemically and genetically remodeling of proteins with ligand binding specificities can be utilized to synthesize various protein-based microsensors for detecting single biomolecules. Here, we describe the construction and characterization of fluorophore-labeled glutamine binding proteins (QBP) and derivatives coupled to the independently designed hydrophobic polypeptide (E12) that can adhere onto solid surfaces via hydrophobic interactions. The single cysteine mutant (N160C QBP) modified with the three environmentally sensitive fluorescent dyes (IAANS, acrylodan, and IANBD ester) showed increased changes in fluorescence intensity induced by glutamine binding. The use of these conjugates as reagentless fluorescence sensors enables us to determine the glutamine concentrations (0.1-50 microM) in homogeneous solution. The fusion of N160C QBP with E12, (Gly4-Ser)n spacers (GSn), and IANBD resulted in the novel fluorescence sensing elements having an adhering capability to hydrophobic surfaces of unmodified microplates. In ELISA and fluorescence experiments for the microplates treated with a series of the conjugates, IANBD-labeled N160C QBP-GS1-E12 displayed the best reproducibility in adhesion onto the hydrophobic surfaces and the precise correlation between fluorescence changes and glutamine concentrations. The performance of the biosensor-attached microplate for glutamine titrations demonstrated that the hydrophobic interaction of E12 with solid surfaces is useful for effective immobilization of proteins that need specific conformational movements in recognizing particular biomolecules. Therefore, the technique using E12 as a surface-linking domain for protein adhesion onto unmodified substrates could be applied effectively to prepare microplates/arrays for a wide variety of high-throughput assays on chemical and biological samples.

Manganese-calcium intermixing facilitates heteroepitaxial growth at the (1014) calcite-water interface

DOE PAGES

Xu, Man; Riechers, Shawn L.; Ilton, Eugene S.; ...

2017-09-05

For this research, in situ atomic force microscopy (AFM) measurements were performed to probe surface precipitates that formed on the (10more » $$\\bar{1}$$4) surface of calcite (CaCO 3) single crystals following reaction with Mn2 +-bearing aqueous solutions. Three-dimensional epitaxial islands were observed to precipitate and grow on the surfaces. In situ time-sequenced measurements demonstrated that the growth rates were commensurate with those obtained for epitaxial islands formed on calcite crystals reacted with Cd2 +-bearing aqueous solutions of the same range in supersaturation with respect to the pure metal carbonate phase. This finding was unexpected as rhodochrosite (MnCO 3) and calcite display a 10% lattice mismatch, based on the area of their (10$$\\bar{1}$$4) surface unit cells, whereas the lattice mismatch is only 4% for otavite (CdCO 3) and calcite. Coatings of varying thicknesses were therefore synthesized by reacting calcite single crystals in calcite-equilibrated aqueous solutions with up to 250 μM MnCl 2. Ex situ X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray reflectivity (XRR), and AFM measurements of the reacted crystals demonstrated the formation of an epitaxial (Mn,Ca)CO 3 solid solution. The epitaxial solid solution had a spatially complex composition, whereby the first few nanometers were rich in Ca and the Mn content increased with distance from the original calcite surface, culminating in a topmost region of almost pure MnCO 3 for the thickest coatings. The effective lattice mismatch was therefore much smaller than the nominal mismatch thus explaining the measured growth rates. Lastly, these findings highlight the strong influence played by the substrate on the composition of surface precipitates in aqueous conditions.« less

A high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen

NASA Astrophysics Data System (ADS)

Luo, ZhiJie; Luo, JianKun; Zhao, WenWen; Cao, Yang; Lin, WeiJie; Zhou, GuoFu

2018-02-01

Electrowetting display technology is realized by tuning the surface energy of a hydrophobic surface by applying a voltage based on electrowetting mechanism. With the rapid development of the electrowetting industry, how to analyze efficiently the quality of an electrowetting display screen has a very important significance. There are two kinds of dead pixels on the electrowetting display screen. One is that the oil of pixel cannot completely cover the display area. The other is that indium tin oxide semiconductor wire connecting pixel and foil was burned. In this paper, we propose a high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen. First, we built an aperture ratio-capacitance model based on the electrical characteristics of electrowetting display. A field-programmable gate array is used as the integrated logic hub of the system for a highly reliable and efficient control of the circuit. Dead pixels can be detected and displayed on a PC-based 2D graphical interface in real time. The proposed dead pixel detection scheme reported in this work has promise in automating electrowetting display experiments.

A Human Subject Evaluation of Airport Surface Situational Awareness Using Prototypical Flight Deck Electronic Taxi Chart Displays

DOT National Transportation Integrated Search

1995-11-01

A study was conducted to test the effect on airport surface situational awareness of GPS derived position information : depicted on a prototypical electronic taxi chart display. The effect of position error and position uncertainty : symbology were a...

Pulse propagation, dispersion, and energy in magnetic materials.

PubMed

Scalora, Michael; D'Aguanno, Giuseppe; Mattiucci, Nadia; Akozbek, Neset; Bloemer, Mark J; Centini, Marco; Sibilia, Concita; Bertolotti, Mario

2005-12-01

We discuss pulse propagation effects in generic, electrically and magnetically dispersive media that may display large material discontinuities, such as a surface boundary. Using the known basic constitutive relations between the fields, and an explicit Taylor expansion to describe the dielectric susceptibility and magnetic permeability, we derive expressions for energy density and energy dissipation rates, and equations of motion for the coupled electric and magnetic fields. We then solve the equations of motion in the presence of a single interface, and find that in addition to the now-established negative refraction process an energy exchange occurs between the electric and magnetic fields as the pulse traverses the boundary.

Performance characterization of a single bi-axial scanning MEMS mirror-based head-worn display

NASA Astrophysics Data System (ADS)

Liang, Minhua

2002-06-01

The NomadTM Personal Display System is a head-worn display (HWD) with a see-through, high-resolution, high-luminance display capability. It is based on a single bi-axial scanning MEMS mirror. In the Nomad HWD system, a red laser diode emits a beam of light that is scanned bi-axially by a single MEMS mirror. A diffractive beam diffuser and an ocular expand the beam to form a 12mm exit pupil for comfortable viewing. The Nomad display has an SVGA (800x600) resolution, 60Hz frame rate, 23-degree horizontal field of view (FOV) and 3:4 vertical to horizontal aspect ratio, a luminance of 800~900 foot-Lamberts, see-through capability, 30mm eye-relief distance, and 1-foot to infinity focusing adjustment. We have characterized the performance parameters, such as field of view, distortion, contrast ratio (4x4 black and white checker board), modulation depth, exit pupil size, eye relief distance, maximum luminance, dynamic range ratio (full-on-to-full-off ratio), dimming ratio, and luminance uniformity at image plane. The Class-1 eye-safety requirements per IEC 60825-1 Amendment 2 (CDRH Laser Notice No. 50) are analyzed and verified by experiments. The paper describes all of the testing methods and set-ups as well as the representative test results. The test results demonstrate that the Nomad display is an eye-safe display product with good image quality and good user ergonomics.

Applying Human Factors Evaluation and Design Guidance to a Nuclear Power Plant Digital Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas Ulrich; Ronald Boring; William Phoenix

2012-08-01

The United States (U.S.) nuclear industry, like similar process control industries, has moved toward upgrading its control rooms. The upgraded control rooms typically feature digital control system (DCS) displays embedded in the panels. These displays gather information from the system and represent that information on a single display surface. In this manner, the DCS combines many previously separate analog indicators and controls into a single digital display, whereby the operators can toggle between multiple windows to monitor and control different aspects of the plant. The design of the DCS depends on the function of the system it monitors, but revolvesmore » around presenting the information most germane to an operator at any point in time. DCSs require a carefully designed human system interface. This report centers on redesigning existing DCS displays for an example chemical volume control system (CVCS) at a U.S. nuclear power plant. The crucial nature of the CVCS, which controls coolant levels and boration in the primary system, requires a thorough human factors evaluation of its supporting DCS. The initial digital controls being developed for the DCSs tend to directly mimic the former analog controls. There are, however, unique operator interactions with a digital vs. analog interface, and the differences have not always been carefully factored in the translation of an analog interface to a replacement DCS. To ensure safety, efficiency, and usability of the emerging DCSs, a human factors usability evaluation was conducted on a CVCS DCS currently being used and refined at an existing U.S. nuclear power plant. Subject matter experts from process control engineering, software development, and human factors evaluated the DCS displays to document potential usability issues and propose design recommendations. The evaluation yielded 167 potential usability issues with the DCS. These issues should not be considered operator performance problems but rather opportunities identified by experts to improve upon the design of the DCS. A set of nine design recommendations was developed to address these potential issues. The design principles addressed the following areas: (1) color, (2) pop-up window structure, (3) navigation, (4) alarms, (5) process control diagram, (6) gestalt grouping, (7) typography, (8) terminology, and (9) data entry. Visuals illustrating the improved DCS displays accompany the design recommendations. These nine design principles serve as the starting point to a planned general DCS style guide that can be used across the U.S. nuclear industry to aid in the future design of effective DCS interfaces.« less

The Taxiway Navigation and Situation Awareness (T-NASA) System

NASA Technical Reports Server (NTRS)

Foyle, David C.; Sridhar, Banavar (Technical Monitor)

1997-01-01

The goal of NASA's Terminal Area Productivity (TAP) Low-Visibility Landing and Surface Operations (LVLASO) subelement is to improve the efficiency of airport surface operations for commercial aircraft operating in weather conditions to Category IIIB while maintaining a high degree of safety. Currently, surface operations are one of the least technologically sophisticated components of the air transport system, being conducted in the 1990's with the same basic technology as in the 1930's. Pilots are given little or no explicit information about their current position, and routing information is limited to ATC communications and airport charts. In TAP/LVLASO, advanced technologies such as satellite navigation systems, digital data communications, advanced information presentation technology, and ground surveillance systems will be integrated into flight deck displays to enable expeditious and safe traffic movement on the airport surface. The cockpit display suite is called the T-NASA (Taxiway Navigation and Situation Awareness) System. This system has three integrated components: 1) Moving Map track-up airport surface display with own-ship, traffic and graphical route guidance 2) Scene-Linked Symbology - route/taxi information virtually projected via a Head-up Display (HUD) onto the forward scene; and, 3) 3-D Audio Ground Collision Avoidance and Navigation system - spatially-localized auditory traffic and navigation alerts. In the current paper, the design philosophy of the T-NASA system will be presented, and the T-NASA system display components described.

A search for cataclysmic binaries containing strongly magnetic white dwarfs

NASA Technical Reports Server (NTRS)

Bond, H. E.; Chanmugam, G.

1982-01-01

The AM Herculis type binaries which contain accreting white dwarfs with surface magnetic fields of a few times 10 to the seventh power gauss were studied. If white dwarfs in cataclysmic binaries have a range of field strengths similar to that among single white dwarfs. AM Her like systems should exist with fields as high as 3 x 10 to the eighth power gauss. It is suggested that such objects will not have the strong optical polarization of the AM Her variables; however, they exhibit high harmonic cyclotron emission, making them spectacular UV sources. We made IUE observations of seven candidate cataclysmic variables selected for optical similarity to AM Her binaries. Although all seven objects were detected in the UV, none display unusually strong UV continua. It is suggested that the distribution of magnetic field strengths among single white dwarfs may be different from that among binaries.

Through-space transfer of chiral information mediated by a plasmonic nanomaterial

NASA Astrophysics Data System (ADS)

Ostovar Pour, Saeideh; Rocks, Louise; Faulds, Karen; Graham, Duncan; Parchaňský, Václav; Bouř, Petr; Blanch, Ewan W.

2015-07-01

The ability to detect chirality gives stereochemically attuned nanosensors the potential to revolutionize the study of biomolecular processes. Such devices may structurally characterize the mechanisms of protein-ligand binding, the intermediates of amyloidogenic diseases and the effects of phosphorylation and glycosylation. We demonstrate that single nanoparticle plasmonic reporters, or nanotags, can enable a stereochemical response to be transmitted from a chiral analyte to an achiral benzotriazole dye molecule in the vicinity of a plasmon resonance from an achiral metallic nanostructure. The transfer of chirality was verified by the measurement of mirror image surface enhanced resonance Raman optical activity spectra for the two enantiomers of both ribose and tryptophan. Computational modelling confirms these observations and reveals the novel chirality transfer mechanism responsible. This is the first report of colloidal metal nanoparticles in the form of single plasmonic substrates displaying an intrinsic chiral sensitivity once attached to a chiral molecule.

Mechanism of interactions between CMC binder and Si single crystal facets.

PubMed

Vogl, U S; Das, P K; Weber, A Z; Winter, M; Kostecki, R; Lux, S F

2014-09-02

Interactions of the active material particles with the binder are crucial in tailoring the properties of composite electrodes used in lithium-ion batteries. The dependency of the protonation degree of the carboxyl group in the carboxymethyl cellulose (CMC) structure on the pH value of the preparation solution was investigated by Fourier transform infrared spectroscopy (FTIR). Three different distinctive chemical states of CMC binder were chosen (protonated, deprotonated, and half-half), and their interactions with different silicon single crystal facets were investigated. The different Si surface orientations display distinct differences of strength of interactions with the CMC binder. The CMC/Si adhesion forces in solution and Si wettability of the silicon are also strongly dependent on the protonation degree of the CMC. This work provides an insight into the nature of these interactions, which determine the electrochemical performance of silicon composite electrodes.

Equilibrium Atmospheric Response to North Atlantic SST Anomalies.

NASA Astrophysics Data System (ADS)

Kushnir, Yochanan; Held, Isaac M.

1996-06-01

The equilibrium general circulation model (GCM) response to sea surface temperature (SST) anomalies in the western North Atlantic region is studied. A coarse resolution GCM, with realistic lower boundary conditions including topography and climatological SST distribution, is integrated in perpetual January and perpetual October modes, distinguished from one another by the strength of the midlatitude westerlies. An SST anomaly with a maximum of 4°C is added to the climatological SST distribution of the model with both positive and negative polarity. These anomaly runs are compared to one another, and to a control integration, to determine the atmospheric response. In all cases warming (cooling) of the midlatitude ocean surface yields a warming (cooling) of the atmosphere over and to the east of the SST anomaly center. The atmospheric temperature change is largest near the surface and decreases upward. Consistent with this simple thermal response, the geopotential height field displays a baroclinic response with a shallow anomalous low somewhat downstream from the warm SST anomaly. The equivalent barotropic, downstream response is weak and not robust. To help interpret the results, the realistic GCM integrations are compared with parallel idealized model runs. The idealized model has full physics and a similar horizontal and vertical resolution, but an all-ocean surface with a single, permanent zonal asymmetry. The idealized and realistic versions of the GCM display compatible response patterns that are qualitatively consistent with stationary, linear, quasigeostrophic theory. However, the idealized model response is stronger and more coherent. The differences between the two model response patterns can be reconciled based on the size of the anomaly, the model treatment of cloud-radiation interaction, and the static stability of the model atmosphere in the vicinity of the SST anomaly. Model results are contrasted with other GCM studies and observations.

Data recording and trend display during anaesthesia using 'MacLab'.

PubMed

Kennedy, R R

1991-08-01

A single screen display of variables monitored during anaesthesia may be ergonomically superior to the 'stack' of monitors seen in many anaesthetising locations. A system based on a MacLab (Analogue Digital Instruments) analogue-to-digital convertor used in conjunction with a Macintosh computer was evaluated. The system was configured to provide trend displays of up to eight variables on a single screen. It was found to be a useful adjunct to monitoring during anaesthesia. Advantages of this system are low cost, flexibility, and the quality of the software and support provided. Limitations of this and other similar systems are discussed.

Real-time 3D human pose recognition from reconstructed volume via voxel classifiers

NASA Astrophysics Data System (ADS)

Yoo, ByungIn; Choi, Changkyu; Han, Jae-Joon; Lee, Changkyo; Kim, Wonjun; Suh, Sungjoo; Park, Dusik; Kim, Junmo

2014-03-01

This paper presents a human pose recognition method which simultaneously reconstructs a human volume based on ensemble of voxel classifiers from a single depth image in real-time. The human pose recognition is a difficult task since a single depth camera can capture only visible surfaces of a human body. In order to recognize invisible (self-occluded) surfaces of a human body, the proposed algorithm employs voxel classifiers trained with multi-layered synthetic voxels. Specifically, ray-casting onto a volumetric human model generates a synthetic voxel, where voxel consists of a 3D position and ID corresponding to the body part. The synthesized volumetric data which contain both visible and invisible body voxels are utilized to train the voxel classifiers. As a result, the voxel classifiers not only identify the visible voxels but also reconstruct the 3D positions and the IDs of the invisible voxels. The experimental results show improved performance on estimating the human poses due to the capability of inferring the invisible human body voxels. It is expected that the proposed algorithm can be applied to many fields such as telepresence, gaming, virtual fitting, wellness business, and real 3D contents control on real 3D displays.

Synthesis, crystal structure, Hirshfeld surfaces analysis and anti-ischemic activity of cinnamide derivatives

NASA Astrophysics Data System (ADS)

Zhong, Jian-gang; Han, Jia-pei; Li, Xiao-feng; Xu, Yi; Zhong, Yan; Wu, Bin

2018-02-01

Two cinnamide derivatives, namely, (E)-1-(4-(bis(4-methylphenyl)- methyl)piperazin-1-yl)-3-(3,4-diethoxyphenyl)prop-2-en-1-one (5) and (E)-1-(4-(bis- (4-fluorophenyl)methyl)piperazin-1-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (6), have been synthesized and characterized by IR spectra, High resolution mass spectra, 1H NMR spectra, 13C NMR spectra. The compound 5 is a novel compound and has never been reported in the literature. Their crystal structures were studied by single-crystal X-ray diffraction. They all crystallize in the monoclinic system. The single-crystal X-ray revealed that compound 5 has infinite X-shaped 1-D polymeric chains structure and compound 6 has a layered 3-D structure by intermolecular interactions. Hirshfeld surface analysis demonstrated the presence of H⋯H, O⋯H, C⋯H, F⋯H, Csbnd H⋯π and π⋯π intermolecular interactions. In addition, the MTT assay results indicated that the compounds 5 and 6 display effective activities against neurotoxicity which is induced by glutamine in PC12 cells. The in vivo experiment indicated that the compound 6 has a good protective effect on cerebral infarction.

Combined imaging and chemical sensing using a single optical imaging fiber.

PubMed

Bronk, K S; Michael, K L; Pantano, P; Walt, D R

1995-09-01

Despite many innovations and developments in the field of fiber-optic chemical sensors, optical fibers have not been employed to both view a sample and concurrently detect an analyte of interest. While chemical sensors employing a single optical fiber or a noncoherent fiberoptic bundle have been applied to a wide variety of analytical determinations, they cannot be used for imaging. Similarly, coherent imaging fibers have been employed only for their originally intended purpose, image transmission. We herein report a new technique for viewing a sample and measuring surface chemical concentrations that employs a coherent imaging fiber. The method is based on the deposition of a thin, analyte-sensitive polymer layer on the distal surface of a 350-microns-diameter imaging fiber. We present results from a pH sensor array and an acetylcholine biosensor array, each of which contains approximately 6000 optical sensors. The acetylcholine biosensor has a detection limit of 35 microM and a fast (< 1 s) response time. In association with an epifluorescence microscope and a charge-coupled device, these modified imaging fibers can display visual information of a remote sample with 4-microns spatial resolution, allowing for alternating acquisition of both chemical analysis and visual histology.

Surface display and bioactivity of Bombyx mori acetylcholinesterase on Pichia pastoris

USDA-ARS?s Scientific Manuscript database

To construct the Pichia pastoris (P. pastoris) cell surface display system of Bombyx mori acetylcholinesterase (BmAChE), the gene for the anchor protein (AGa1) was obtained from Saccharomyces cerevisiae and was fused with the modified Bombyx mori acetylcholinesterase gene (bmace) and transformed int...

Taxiway Navigation and Situation Awareness (T-NASA) System : problem, design philosophy, and description of an integrated display suite for low-visibility airport surface operations

DOT National Transportation Integrated Search

1996-01-01

An integrated cockpit display suite, the T-NASA (Taxiway Navigation and : Situation Awareness) system, is under development for NASA's Terminal Area : Productivity (TAP) Low-Visibility Landing and Surface Operations (LVLASO) : program. This system ha...

M13 bacteriophage coat proteins engineered for improved phage display.

PubMed

Sidhu, Sachdev S; Feld, Birte K; Weiss, Gregory A

2007-01-01

This chapter describes a method for increasing levels of protein fusions displayed on the surfaces of M13 bacteriophage particles. By introducing mutations into the anchoring M13 coat protein, protein display levels can be increased by up to two orders of magnitude. Experimental methods are presented for the design, construction, and screening of phage-displayed libraries for improved protein display.

Phage as a template to grow bone mineral nanocrystals.

PubMed

Cao, Binrui; Xu, Hong; Mao, Chuanbin

2014-01-01

Phage display is a biotechnique that fuses functional peptides on the outer surface of filamentous phage by inserting DNA encoding the peptides into the genes of its coat proteins. The resultant peptide-displayed phage particles have been widely used as biotemplates for the synthesis of functional hybrid nanomaterials. Here, we describe the bioengineering of M13 filamentous phage to surface-display bone mineral (hydroxyapatite (HAP))-nucleating peptides derived from dentin matrix protein-1 and using the engineered phage as a biotemplate to grow HAP nanocrystals.

Method and device for measuring single-shot transient signals

DOEpatents

Yin, Yan

2004-05-18

Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.

Survey Summary of AGATE Concepts Demonstration at Annual NATA Convention, March 24-26, 1997. Volume 1; Basic Report

NASA Technical Reports Server (NTRS)

1997-01-01

An AGATE Concepts Demonstration was conducted at the annual National Air Transportation Association (NATA) Convention in 1997. Following a 5-minute introductory briefing, an interactive simulation of a single-pilot, single-engine aircraft was conducted. The participant was able to take off, fly a brief enroute segment, fly a Global Positioning System (GPS) approach and landing, and repeat the approach and landing segment. The participant was provided an advanced "highway-in-the-sky" presentation on both a simulated head-up display and on a large LCD head-down display to follow throughout the flight. A single-lever power control and display concept was also provided for control of the engine throughout the flight. A second head-down, multifunction display in the instrument panel provided a moving map display for navigation purposes and monitoring of the status of the aircraft's systems. An estimated 100 people observed or participated in the demonstration, and 68 surveys were collected. The pilot ratings of the participants ranged from student to Air Transport Rating with an average of 6089 hours total flight time. The overwhelming response was that technologies that simplify piloting tasks are enthusiastically welcomed by pilots of all experience levels. The increase in situation awareness and use of the head-up display were universally accepted and lauded as steps in the right direction.

Multiresolution wavelet analysis for efficient analysis, compression and remote display of long-term physiological signals.

PubMed

Khuan, L Y; Bister, M; Blanchfield, P; Salleh, Y M; Ali, R A; Chan, T H

2006-06-01

Increased inter-equipment connectivity coupled with advances in Web technology allows ever escalating amounts of physiological data to be produced, far too much to be displayed adequately on a single computer screen. The consequence is that large quantities of insignificant data will be transmitted and reviewed. This carries an increased risk of overlooking vitally important transients. This paper describes a technique to provide an integrated solution based on a single algorithm for the efficient analysis, compression and remote display of long-term physiological signals with infrequent short duration, yet vital events, to effect a reduction in data transmission and display cluttering and to facilitate reliable data interpretation. The algorithm analyses data at the server end and flags significant events. It produces a compressed version of the signal at a lower resolution that can be satisfactorily viewed in a single screen width. This reduced set of data is initially transmitted together with a set of 'flags' indicating where significant events occur. Subsequent transmissions need only involve transmission of flagged data segments of interest at the required resolution. Efficient processing and code protection with decomposition alone is novel. The fixed transmission length method ensures clutter-less display, irrespective of the data length. The flagging of annotated events in arterial oxygen saturation, electroencephalogram and electrocardiogram illustrates the generic property of the algorithm. Data reduction of 87% to 99% and improved displays are demonstrated.

Anti-CDR3 Therapy for B-Cell Malignancies

DTIC Science & Technology

2014-10-01

are happy to summarize substantial completion of Task 3. Fig 3 shows a schematic of an M13 phage displaying a single chain Fv. The Tomlinson I phage...the M13 bacteriophage displaying a single chain Fv fused with one copy of the pIII protein. HC LC T A G CDR3 CDR2 CDR1 CDR2 CDR3 CDR1 p

Simultaneous surface display and cargo loading of encapsulin nanocompartments and their use for rational vaccine design.

PubMed

Lagoutte, Priscillia; Mignon, Charlotte; Stadthagen, Gustavo; Potisopon, Supanee; Donnat, Stéphanie; Mast, Jan; Lugari, Adrien; Werle, Bettina

2018-05-11

In the past decades protein nanoparticles have successfully been used for vaccine applications. Their particulate nature and dense repetitive subunit organization makes them perfect carriers for antigen surface display and confers high immunogenicity. Nanoparticles have emerged as excellent candidates for vectorization of biological and immunostimulating molecules. Nanoparticles and biomolecular nanostructures such as ferritins or virus like particles have been used as diagnostic and therapeutic delivery systems, in vaccine development, as nanoreactors, etc. Recently, a new class of bacterial protein compartment has been discovered referred to as encapsulin nanocompartment. These compartments have been used for targeted diagnostics, as therapeutic delivery systems and as nanoreactors. Their biological origin makes them conveniently biocompatible and allows genetic functionalization. The aim of our study was to implement encapsulin nanocompartements for simultaneous epitope surface display and heterologous protein loading for rational vaccine design. For this proof-of-concept-study, we produced Thermotoga maritima encapsulin nanoparticles in E. coli. We demonstrated the ability of simultaneous display in our system by inserting Matrix protein 2 ectodomain (M2e) of influenza A virus at the nanoparticle surface and by packaging of a fluorescent reporter protein (GFP) into the internal cavity. Characterization of the nanoparticles by electronic microscopy confirmed homogenously shaped particles of 24 nm diameter in average. The results further show that engineering of the particle surface improved the loading capacity of the heterologous reporter protein suggesting that surface display may induce a critical elastic deformation resulting in improved stiffness. In Balb/c mice, nanoparticle immunization elicited antibody responses against both the surface epitope and the loaded cargo protein. These results confirm the potential of encapsulin nanocompartments for customized vaccine design and antigen delivery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Distinguishing Different Strategies of Across-Dimension Attentional Selection

ERIC Educational Resources Information Center

Huang, Liqiang; Pashler, Harold

2012-01-01

Selective attention in multidimensional displays has usually been examined using search tasks requiring the detection of a single target. We examined the ability to perceive a spatial structure in multi-item subsets of a display that were defined either conjunctively or disjunctively. Observers saw two adjacent displays and indicated whether the…

14 CFR 255.4 - Display of information.

Code of Federal Regulations, 2010 CFR

2010-01-01

... with the requirements of this section. (1) Each system must offer an integrated display that uses the.... (2) Each integrated display offered by a system must either use elapsed time as a significant factor in selecting service options from the database or give single-plane flights a preference over...

Emissive and reflective properties of curved displays in relation to image quality

NASA Astrophysics Data System (ADS)

Boher, Pierre; Leroux, Thierry; Bignon, Thibault; Collomb-Patton, Véronique; Blanc, Pierre; Sandré-Chardonnal, Etienne

2016-03-01

Different aspects of the characterization of curved displays are presented. The limit of validity of viewing angle measurements without angular distortion on such displays using goniometer or Fourier optics viewing angle instrument is given. If the condition cannot be fulfilled the measurement can be corrected using a general angular distortion formula as demonstrated experimentally using a Samsung Galaxy S6 edge phone display. The reflective properties of the display are characterized by measuring the spectral BRDF using a multispectral Fourier optics viewing angle system. The surface of a curved OLED TV has been measured. The BDRF patterns show a mirror like behavior with and additional strong diffraction along the pixels lines and columns that affect the quality of the display when observed with parasitic lighting. These diffraction effects are very common on OLED surfaces. We finally introduce a commercial ray tracing software that can use directly the measured emissive and reflective properties of the display to make realistic simulation under any lighting environment.

Airborne lidar and radiometric observations of PBL- and low clouds

NASA Technical Reports Server (NTRS)

Flamant, P. H.; Valentin, R.; Pelon, J.

1992-01-01

Boundary layer- and low altitude clouds over open ocean and continent areas have been studied during several field campaigns since mid-1990 using the French airborne backscatter lidar LEANDRE in conjunction with on-board IR and visible radiometers. LEANDRE is an automatic system, and a modification of the instrumental parameters, when airborne, is computer controlled through an operator keyboard. The vertical range squared lidar signals and instrument status are displayed in real time on two dedicated monitors. The lidar is used either down- or up-looking while the aircraft is flying above or below clouds. A switching of the viewing configuration takes about a minute. The lidar measurements provide a high resolution description of cloud morphology and holes in cloud layers. The flights were conducted during various meteorological conditions on single or multilayer stratocumulus and cumulus decks. Analysis on a single shot basis of cloud top (or bottom) altitude and a plot of the corresponding histogram allows one to determine a probability density function (PDF). The preliminary results show the PDFs for cloud top are not Gaussian and symmetric about the mean value. The skewness varies with atmospheric conditions. An example of results recorded over the Atlantic ocean near Biarritz is displayed, showing: (1) the range squared lidar signals as a function of time (here 100 s corresponds to about 8 km, 60 shots are averaged on horizontal); the Planetary Boundary Layer (PBL) - up to 600 m - is observed at the beginning of the leg as well as on surface returns, giving an indication of the porosity; (2) the cloud top altitude variation between 2.4 to 2.8 km during the 150 to 320 s section; and (3) the corresponding PDF. Similar results are obtained on stratocumulus over land. Single shot measurements can be used also to determine an optical porosity at a small scale as well as a fractional cloudiness at a larger scale. A comparison of cloud top altitude retrieved from lidar and narrowbeam IR radiometer is conducted to study the scale integration problem. A good agreement within less than 100 m relies on spatial uniformity and an optically thick layer. In the presence of holes, a discrepancy is observed. This is illustrated in figure 2, displaying as a function of time (1) the lidar signals; (2) the target temperature (either clouds or sea surface) retreived from a narrowbeam IR radiometer, 17 C is the sea surface temperature on that day; and (3) the visible flux, linked to cloud albedo, measured by a pyranometer. In preparation of ASTEX, down- and up-looking measurements where conducted on stratocumulus clouds over the Atlantic Ocean near Quimper in Brittany. Depending on the flight pattern orientation with respect to the wind, the top and bottom cloud morphologies are different. Preliminary results are given on cloud morphology, cloud top PDFs, optical porosity, fractional cloudiness, and comparison of lidar and radiometric measurements.

Enhanced vision flight deck technology for commercial aircraft low-visibility surface operations

NASA Astrophysics Data System (ADS)

Arthur, Jarvis J.; Norman, R. M.; Kramer, Lynda J.; Prinzel, Lawerence J.; Ellis, Kyle K.; Harrison, Stephanie J.; Comstock, J. R.

2013-05-01

NASA Langley Research Center and the FAA collaborated in an effort to evaluate the effect of Enhanced Vision (EV) technology display in a commercial flight deck during low visibility surface operations. Surface operations were simulated at the Memphis, TN (FAA identifier: KMEM) airfield during nighttime with 500 Runway Visual Range (RVR) in a high-fidelity, full-motion simulator. Ten commercial airline flight crews evaluated the efficacy of various EV display locations and parallax and minification effects. The research paper discusses qualitative and quantitative results of the simulation experiment, including the effect of EV display placement on visual attention, as measured by the use of non-obtrusive oculometry and pilot mental workload. The results demonstrated the potential of EV technology to enhance situation awareness which is dependent on the ease of access and location of the displays. Implications and future directions are discussed.

Enhanced Vision Flight Deck Technology for Commercial Aircraft Low-Visibility Surface Operations

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J., III; Norman, R. Michael; Kramer, Lynda J.; Prinzel, Lawrence J., III; Ellis, Kyle K. E.; Harrison, Stephanie J.; Comstock, J. Ray

2013-01-01

NASA Langley Research Center and the FAA collaborated in an effort to evaluate the effect of Enhanced Vision (EV) technology display in a commercial flight deck during low visibility surface operations. Surface operations were simulated at the Memphis, TN (FAA identifier: KMEM) air field during nighttime with 500 Runway Visual Range (RVR) in a high-fidelity, full-motion simulator. Ten commercial airline flight crews evaluated the efficacy of various EV display locations and parallax and mini cation effects. The research paper discusses qualitative and quantitative results of the simulation experiment, including the effect of EV display placement on visual attention, as measured by the use of non-obtrusive oculometry and pilot mental workload. The results demonstrated the potential of EV technology to enhance situation awareness which is dependent on the ease of access and location of the displays. Implications and future directions are discussed.

Phenylacetic acid co-crystals with acridine, caffeine, isonicotinamide and nicotinamide: Crystal structures, thermal analysis, FTIR spectroscopy and Hirshfeld surface analysis

NASA Astrophysics Data System (ADS)

Amombo Noa, Francoise M.; Jacobs, Ayesha

2017-07-01

Co-crystals of phenylacetic acid (PAA) with acridine (ACR), caffeine (CAF), isonicotinamide (INM) and nicotinamide (NAM) have been successfully prepared and characterised by single crystal X-ray diffraction, FTIR spectroscopy, thermal analysis and Hirshfeld surface analysis. The ACR, INM and NAM co-crystals with PAA exhibit the carboxylic acid-pyridine heterosynthon. Furthermore the amide-amide supramolecular homosynthon is observed in the PAA co-crystals with INM and NAM as well as Nsbnd H⋯O interactions between the acid and the respective base. The CAF co-crystal exhibits hydrogen bonding between the imidazole nitrogen and the COOH group of the PAA. The compounds demonstrate different stoichiometries; for PAA·ACR and PAA·INM a 1:1 ratio is displayed, a 2:1 in 2PAA·CAF and a 2:2 in the case of 2PAA·2NAM.

Tailoring Dirac Fermions in Molecular Graphene

NASA Astrophysics Data System (ADS)

Gomes, Kenjiro K.; Mar, Warren; Ko, Wonhee; Camp, Charlie D.; Rastawicki, Dominik K.; Guinea, Francisco; Manoharan, Hari C.

2012-02-01

The dynamics of electrons in solids is tied to the band structure created by a periodic atomic potential. The design of artificial lattices, assembled through atomic manipulation, opens the door to engineer electronic band structure and to create novel quantum states. We present scanning tunneling spectroscopic measurements of a nanoassembled honeycomb lattice displaying a Dirac fermion band structure. The artificial lattice is created by atomic manipulation of single CO molecules with the scanning tunneling microscope on the surface of Cu(111). The periodic potential generated by the assembled CO molecules reshapes the band structure of the two-dimensional electron gas, present as a surface state of Cu(111), into a ``molecular graphene'' system. We create local defects in the lattice to observe the quasiparticle interference patterns that unveil the underlying band structure. We present direct comparison between the tunneling data, first-principles calculations of the band structure, and tight-binding models.

Juno is the egg Izumo receptor and is essential for mammalian fertilisation

PubMed Central

Bianchi, Enrica; Doe, Brendan; Goulding, David; Wright, Gavin J.

2014-01-01

Fertilisation occurs when sperm and egg recognise each other and fuse to form a new, genetically distinct organism. The molecular basis of sperm-egg recognition is unknown, but is likely to require interactions between receptor proteins displayed on their surface. Izumo1 is an essential sperm cell surface protein, but its egg receptor has remained a mystery. Here, we identify Juno as the receptor for Izumo1 on mouse eggs, and show this interaction is conserved within mammals. Female mice lacking Juno are infertile and Juno-deficient eggs do not fuse with normal sperm. Rapid shedding of Juno from the oolemma after fertilisation suggests a mechanism for the membrane block to polyspermy, ensuring eggs normally fuse with just a single sperm. Our discovery of an essential receptor pair at the nexus of conception provides opportunities for the rational development of new fertility treatments and contraceptives. PMID:24739963

Surface compositional mapping by spectral ratioing of ERTS-1 MSS data in the Wind River Basin and Range, Wyoming

NASA Technical Reports Server (NTRS)

Vincent, R. K. (Principal Investigator); Salmon, B. C.; Pillars, W. W.; Harris, J. E.

1975-01-01

The author has identified the following significant results. ERTS data collected in August and October 1972 were processed on digital and special purpose analog recognition computers using ratio enhancement and pattern recognition. Ratios of band-averaged laboratory reflectances of some minerals and rock types known to be in the scene compared favorably with ratios derived from the data by ratio normalization procedures. A single ratio display and density slice of the visible channels of ERTS MSS data, Channel 5/Channel 4 (R5,4), separated the Triassic Chugwater formation (redbeds) from other formations present and may have enhanced iron oxide minerals present at the surface in abundance. Comparison of data sets collected over the same area at two different times of the year by digital processing indicated that spectral variation due to environmental factors was reduced by ratio processing.

Positron-annihilation study of the electronic structure of URu2Si2

NASA Astrophysics Data System (ADS)

Rozing, G. J.; Mijnarends, P. E.; Menovsky, A. A.; de Chtel, P. F.

1991-04-01

Measurements of the two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed on oriented single crystals of URu2Si2. The spectra, obtained with integration along four different symmetry directions, display anisotropic structure in fair agreement with a previous calculation of the two-photon momentum distribution. In particular, the contribution of the f-ligand hybridized electron states is clearly observed and reasonably well described by the band calculation. The 2D-ACAR distribution remains unchanged as the temperature is increased from 6 K in the Fermi-liquid state to 72 K, which is just above the coherence temperature. The inhomogeneity of the positron density in the unit cell complicates the Lock-Crisp-West (LCW) analysis of the experiments in terms of Fermi-surface features. Nevertheless, the disagreement between theory and experiment after LCW folding indicates that the Fermi surface as predicted by local-density-approximation band theory does not apply.

A Phase-Separation Route to Synthesize Porous CNTs with Excellent Stability for Na+ Storage.

PubMed

Chen, Zhi; Wang, Taihong; Zhang, Ming; Cao, Guozhong

2017-06-01

Porous carbon nanotubes (CNTs) are obtained by removing MoO 2 nanoparticles from MoO 2 @C core@shell nanofibers which are synthesized by phase-segregation via a single-needle electrospinning method. The specific surface area of porous CNTs is 502.9 m 2 g -1 , and many oxygen-containing functional groups (COH, CO) are present. As anodes for sodium-ion batteries, the porous CNT electrode displays excellent rate performance and cycling stability (110 mA h g -1 after 1200 cycles at 5 A g -1 ). Those high properties can be attributed to the porous structure and surface modification to steadily store Na + with high capacity. The work provides a facile and broadly applicable way to fabricate the porous CNTs and their composites for batteries, catalysts, and fuel cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and screening of M13 phage display cDNA libraries.

PubMed

Georgieva, Yuliya; Konthur, Zoltán

2011-02-17

The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction studies. However, the generation and selection of cDNA phage display libraries is subjected to intrinsic biological limitations due to their complex nature and heterogeneity, as well as technical difficulties regarding protein presentation on the phage surface. Here, we review the latest developments in this field, discuss a number of strategies and improvements anticipated to overcome these challenges making cDNA and open reading frame (ORF) libraries more readily accessible for phage display. Furthermore, future trends combining phage display with next generation sequencing (NGS) will be presented.

Information presentation through a head-worn display (“smart glasses”) has a smaller influence on the temporal structure of gait variability during dual-task gait compared to handheld displays (paper-based system and smartphone)

PubMed Central

Sedighi, Alireza; Ulman, Sophia M.

2018-01-01

The need to complete multiple tasks concurrently is a common occurrence both daily life and in occupational activities, which can often include simultaneous cognitive and physical demands. As one example, there is increasing availability of head-worn display technologies that can be employed when a user is mobile (e.g., while walking). This new method of information presentation may, however, introduce risks of adverse outcomes such as a decrement to gait performance. The goal of this study was thus to quantify the effects of a head-worn display (i.e., smart glasses) on motor variability during gait and to compare these effects with those of other common information displays (i.e., smartphone and paper-based system). Twenty participants completed four walking conditions, as a single task and in three dual-task conditions (three information displays). In the dual-task conditions, the information display was used to present several cognitive tasks. Three different measures were used to quantify variability in gait parameters for each walking condition (using the cycle-to-cycle standard deviation, sample entropy, and the “goal-equivalent manifold” approach). Our results indicated that participants used less adaptable gait strategies in dual-task walking using the paper-based system and smartphone conditions compared with single-task walking. Gait performance, however, was less affected during dual-task walking with the smart glasses. We conclude that the risk of an adverse gait event (e.g., a fall) in head-down walking conditions (i.e., the paper-based system and smartphone conditions) were higher than in single-task walking, and that head-worn displays might help reduce the risk of such events during dual-task gait conditions. PMID:29630614

Coherence across consciousness levels: Symmetric visual displays spare working memory resources.

PubMed

Dumitru, Magda L

2015-12-15

Two studies demonstrate that the need for coherence could nudge individuals to use structural similarities between binary visual displays and two concurrent cognitive tasks to unduly solve the latter in similar fashion. In an overt truth-judgement task, participants decided whether symmetric colourful displays matched conjunction or disjunction descriptions (e.g., "the black and/or the orange"). In the simultaneous covert categorisation task, they decided whether a colour name (e.g., "black") described a two-colour object or half of a single-colour object. Two response patterns emerged as follows. Participants either acknowledged or rejected matches between disjunction descriptions and two visual stimuli and, similarly, either acknowledged or rejected matches between single colour names and two-colour objects or between single colour names and half of single-colour objects. These findings confirm the coherence hypothesis, highlight the role of coherence in preserving working-memory resources, and demonstrate an interaction between high-level and low-level consciousness. Copyright © 2015 Elsevier Inc. All rights reserved.

X-Windows Widget for Image Display

NASA Technical Reports Server (NTRS)

Deen, Robert G.

2011-01-01

XvicImage is a high-performance XWindows (Motif-compliant) user interface widget for displaying images. It handles all aspects of low-level image display. The fully Motif-compliant image display widget handles the following tasks: (1) Image display, including dithering as needed (2) Zoom (3) Pan (4) Stretch (contrast enhancement, via lookup table) (5) Display of single-band or color data (6) Display of non-byte data (ints, floats) (7) Pseudocolor display (8) Full overlay support (drawing graphics on image) (9) Mouse-based panning (10) Cursor handling, shaping, and planting (disconnecting cursor from mouse) (11) Support for all user interaction events (passed to application) (12) Background loading and display of images (doesn't freeze the GUI) (13) Tiling of images.

An atlas of monthly mean distributions of GEOSAT sea surface height, SSMI surface wind speed, AVHRR/2 sea surface temperature, and ECMWF surface wind components during 1988

NASA Technical Reports Server (NTRS)

Halpern, D.; Zlotnicki, V.; Newman, J.; Brown, O.; Wentz, F.

1991-01-01

Monthly mean global distributions for 1988 are presented with a common color scale and geographical map. Distributions are included for sea surface height variation estimated from GEOSAT; surface wind speed estimated from the Special Sensor Microwave Imager on the Defense Meteorological Satellite Program spacecraft; sea surface temperature estimated from the Advanced Very High Resolution Radiometer on NOAA spacecrafts; and the Cartesian components of the 10m height wind vector computed by the European Center for Medium Range Weather Forecasting. Charts of monthly mean value, sampling distribution, and standard deviation value are displayed. Annual mean distributions are displayed.

Advanced freeform optics enabling ultra-compact VR headsets

NASA Astrophysics Data System (ADS)

Benitez, Pablo; Miñano, Juan C.; Zamora, Pablo; Grabovičkić, Dejan; Buljan, Marina; Narasimhan, Bharathwaj; Gorospe, Jorge; López, Jesús; Nikolić, Milena; Sánchez, Eduardo; Lastres, Carmen; Mohedano, Ruben

2017-06-01

We present novel advanced optical designs with a dramatically smaller display to eye distance, excellent image quality and a large field of view (FOV). This enables headsets to be much more compact, typically occupying about a fourth of the volume of a conventional headset with the same FOV. The design strategy of these optics is based on a multichannel approach, which reduces the distance from the eye to the display and the display size itself. Unlike conventional microlens arrays, which are also multichannel devices, our designs use freeform optical surfaces to produce excellent imaging quality in the entire field of view, even when operating at very oblique incidences. We present two families of compact solutions that use different types of lenslets: (1) refractive designs, whose lenslets are composed typically of two refractive surfaces each; and (2) light-folding designs that use prism-like three-surface lenslets, in which rays undergo refraction, reflection, total internal reflection and refraction again. The number of lenslets is not fixed, so different configurations may arise, adaptable for flat or curved displays with different aspect ratios. In the refractive designs the distance between the optics and the display decreases with the number of lenslets, allowing for displaying a light-field when the lenslet becomes significantly small than the eye pupil. On the other hand, the correlation between number of lenslets and the optics to display distance is broken in light-folding designs, since their geometry permits achieving a very short display to eye distance with even a small number of lenslets.

How to reinforce perception of depth in single two-dimensional pictures

NASA Technical Reports Server (NTRS)

Nagata, S.

1989-01-01

The physical conditions of the display of single 2-D pictures, which produce images realistically, were studied by using the characteristics of the intake of the information for visual depth perception. Depth sensitivity, which is defined as the ratio of viewing distance to depth discrimination threshold, was introduced in order to evaluate the availability of various cues for depth perception: binocular parallax, motion parallax, accommodation, convergence, size, texture, brightness, and air-perspective contrast. The effects of binocular parallax in different conditions, the depth sensitivity of which is greatest at a distance of up to about 10 m, were studied with the new versatile stereoscopic display. From these results, four conditions to reinforce the perception of depth in single pictures were proposed, and these conditions are met by the old viewing devices and the new high-definition and wide television displays.

Filamentous bacteriophage as a novel therapeutic tool for Alzheimer's disease treatment.

PubMed

Solomon, Beka

2008-10-01

Antibodies towards the N-terminal region of the amyloid-beta peptide (AbetaP) bind to Abeta fibrils, leading to their disaggregation. We developed an immunization procedure using filamentous phages displaying the only four amino acids EFRH encompassing amino acids 3-6 of the 42 residues of AbetaP, found to be the main regulatory site for Abeta formation. Phages displaying EFRH epitope are effective in eliciting humoral response against AbetaP which, in turn, relieves amyloid burden in brains of amyloid-beta protein precursor transgenic mice, improving their ability to perform cognitive tasks. In order to overcome the low permeability of the blood brain barrier for targeting 'anti-aggregating' monoclonal antibodies (mAbs) to Abeta plaques in the brain, we applied antibody engineering methods to minimize the size of mAbs while maintaining their biological activity. Single-chain antibodies displayed on the surface of filamentous phage showed the ability to enter the central nervous system (CNS). The genetically engineered filamentous bacteriophage proved to be an efficient, nontoxic viral delivery vector to the brain, offering an obvious advantage over other mammalian vectors. The feasibility of these novel strategies for production and targeting of anti-aggregating antibodies against Abeta plaques to disease affected regions in the CNS may have clinical potential for treatment of Alzheimer's disease.

Control of soft machines using actuators operated by a Braille display.

PubMed

Mosadegh, Bobak; Mazzeo, Aaron D; Shepherd, Robert F; Morin, Stephen A; Gupta, Unmukt; Sani, Idin Zhalehdoust; Lai, David; Takayama, Shuichi; Whitesides, George M

2014-01-07

One strategy for actuating soft machines (e.g., tentacles, grippers, and simple walkers) uses pneumatic inflation of networks of small channels in an elastomeric material. Although the management of a few pneumatic inputs and valves to control pressurized gas is straightforward, the fabrication and operation of manifolds containing many (>50) independent valves is an unsolved problem. Complex pneumatic manifolds-often built for a single purpose-are not easily reconfigured to accommodate the specific inputs (i.e., multiplexing of many fluids, ranges of pressures, and changes in flow rates) required by pneumatic systems. This paper describes a pneumatic manifold comprising a computer-controlled Braille display and a micropneumatic device. The Braille display provides a compact array of 64 piezoelectric actuators that actively close and open elastomeric valves of a micropneumatic device to route pressurized gas within the manifold. The positioning and geometries of the valves and channels in the micropneumatic device dictate the functionality of the pneumatic manifold, and the use of multi-layer soft lithography permits the fabrication of networks in a wide range of configurations with many possible functions. Simply exchanging micropneumatic devices of different designs enables rapid reconfiguration of the pneumatic manifold. As a proof of principle, a pneumatic manifold controlled a soft machine containing 32 independent actuators to move a ball above a flat surface.

Control of Soft Machines using Actuators Operated by a Braille Display

PubMed Central

Mosadegh, Bobak; Mazzeo, Aaron D.; Shepherd, Robert F.; Morin, Stephen A.; Gupta, Unmukt; Sani, Idin Zhalehdoust; Lai, David; Takayama, Shuichi; Whitesides, George M.

2013-01-01

One strategy for actuating soft machines (e.g., tentacles, grippers, and simple walkers) uses pneumatic inflation of networks of small channels in an elastomeric material. Although the management of a few pneumatic inputs and valves to control pressurized gas is straightforward, the fabrication and operation of manifolds containing many (>50) independent valves is an unsolved problem. Complex pneumatic manifolds—often built for a single purpose—are not easily reconfigured to accommodate the specific inputs (i.e., multiplexing of many fluids, ranges of pressures, and changes in flow rates) required by pneumatic systems. This paper describes a pneumatic manifold comprising a computer-controlled braille display and a micropneumatic device. The braille display provides a compact array of 64 piezoelectric actuators that actively close and open elastomeric valves of a micropneumatic device to route pressurized gas within the manifold. The positioning and geometries of the valves and channels in the micropneumatic device dictate the functionality of the pneumatic manifold, and the use of multi-layer soft lithography permits the fabrication of networks in a wide range of configurations with many possible functions. Simply exchanging micropneumatic devices of different designs enables rapid reconfiguration of the pneumatic manifold. As a proof of principle, a pneumatic manifold controlled a soft machine containing 32 independent actuators to move a ball above a flat surface. PMID:24196070

From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

PubMed

Ishii, Jun; Okazaki, Fumiyoshi; Djohan, Apridah Cameliawati; Hara, Kiyotaka Y; Asai-Nakashima, Nanami; Teramura, Hiroshi; Andriani, Ade; Tominaga, Masahiro; Wakai, Satoshi; Kahar, Prihardi; Yopi; Prasetya, Bambang; Ogino, Chiaki; Kondo, Akihiko

2016-01-01

Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source. Parental yeast S. cerevisiae assimilated mannose and glucose as monomeric sugars, producing ethanol from mannose. We constructed yeast strains that express tethered β-mannanase and β-mannosidase; co-display of the two enzymes on the cell surface was confirmed by immunofluorescence staining and enzyme activity assays. The constructed yeast cells successfully hydrolyzed 1,4-β-d-mannan and produced ethanol by assimilating the resulting mannose without external addition of enzymes. Furthermore, the constructed strain produced ethanol from 1,4-β-d-mannan continually during the third batch of repeated fermentation. Additionally, the constructed strain produced ethanol from ivory nut mannan; ethanol yield was improved by NaOH pretreatment of the substrate. We successfully displayed β-mannanase and β-mannosidase on the yeast cell surface. Our results clearly demonstrate the utility of the strain co-displaying β-mannanase and β-mannosidase for ethanol fermentation from mannan biomass. Thus, co-tethering β-mannanase and β-mannosidase on the yeast cell surface provides a powerful platform technology for yeast fermentation toward the production of bioethanol and other biochemicals from lignocellulosic materials containing mannan components.

Display of the Viral Epitopes on Lactococcus lactis: A Model for Food Grade Vaccine against EV71

PubMed Central

Varma, Nadimpalli Ravi S.; Toosa, Haryanti; Foo, Hooi Ling; Alitheen, Noorjahan Banu Mohamed; Nor Shamsudin, Mariana; Arbab, Ali S.; Yusoff, Khatijah; Abdul Rahim, Raha

2013-01-01

In this study, we have developed a system for display of antigens of Enterovirus type 71 (EV71) on the cell surface of L. lactis. The viral capsid protein (VP1) gene from a local viral isolate was utilized as the candidate vaccine for the development of oral live vaccines against EV71 using L. lactis as a carrier. We expressed fusion proteins in E. coli and purified fusion proteins were incubated with L. lactis. We confirmed that mice orally fed with L. lactis displaying these fusion proteins on its surface were able to mount an immune response against the epitopes of EV71. This is the first example of an EV71 antigen displayed on the surface of a food grade organism and opens a new perspective for alternative vaccine strategies against the EV71. We believe that the method of protein docking utilized in this study will allow for more flexible presentations of short peptides and proteins on the surface of L. lactis to be useful as a delivery vehicle. PMID:23476790

Percolation characteristics of solvent invasion in rough fractures under miscible conditions

NASA Astrophysics Data System (ADS)

Korfanta, M.; Babadagli, T.; Develi, K.

2017-10-01

Surface roughness and flow rate effects on the solvent transport under miscible conditions in a single fracture are studied. Surface replicas of seven different rocks (marble, granite, and limestone) are used to represent different surface roughness characteristics each described by different mathematical models including three fractal dimensions. Distribution of dyed solvent is investigated at various flow rate conditions to clarify the effect of roughness on convective and diffusive mixing. After a qualitative analysis using comparative images of different rocks, the area covered by solvent with respect to time is determined to conduct a semi-quantitative analysis. In this exercise, two distinct zones are identified, namely the straight lines obtained for convective (early times) and diffusive (late times) flow. The bending point between these two lines is used to point the transition between the two zones. Finally, the slopes of the straight lines and the bending points are correlated to five different roughness parameters and the rate (Peclet number). It is observed that both surface roughness and flow rate have significant effect on solvent spatial distribution. The largest area covered is obtained at moderate flow rates and hence not only the average surface roughness characteristic is important, but coessentially total fracture surface area needs to be considered when evaluating fluid distribution. It is also noted that the rate effect is critically different for the fracture samples of large grain size (marbles and granite) compared to smaller grain sizes (limestones). Variogram fractal dimension exhibits the strongest correlation with the maximum area covered by solvent, and display increasing trend at the moderate flow rates. Equations with variogram surface fractal dimension in combination with any other surface fractal parameter coupled with Peclet number can be used to predict maximum area covered by solvent in a single fracture, which in turn can be utilized to model oil recovery, waste disposal, and groundwater contamination processes in the presence of fractures.

Manganese-calcium intermixing facilitates heteroepitaxial growth at the 10 1 ¯ 4 calcite-water interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Man; Riechers, Shawn L.; Ilton, Eugene S.

2017-10-01

In situ atomic force microscopy (AFM) measurements were performed to probe surface precipitates that formed on the (10-14) surface of calcite (CaCO3) single crystals following reaction with Mn2+-bearing aqueous solutions with a range of initial concentrations. Three-dimensional epitaxial islands were observed to precipitate and grow on the surfaces and in situ time-sequenced measurements demonstrated that their growth rates were commensurate with those obtained for epitaxial islands formed on calcite crystals reacted with Cd2+-bearing aqueous solutions of the same range in supersaturation with respect to the pure metal carbonate phase. This finding was unexpected as rhodochrosite (MnCO3) and calcite display amore » 10% lattice mismatch, based on the area of their (10-14) surface unit cells, whereas the lattice mismatch is only 4% for otavite (CdCO3) and calcite. Coatings of varying thicknesses were therefore synthesized by reacting calcite single crystals with calcite-equilibrated aqueous solutions with concentrations of up to 250 µM MnCl2 and analyzed to determine the composition of the surface precipitates. Ex situ X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray reflectivity (XRR), and AFM measurements of the reacted crystals demonstrated the formation of an epitaxial (Mn,Ca)CO3 solid solution with a spatially complex composition atop the calcite surface, whereby the first few nanometers were rich in Ca and the Mn content increased with distance from the original calcite surface, culminating in a topmost region of almost pure MnCO3 for the thickest coatings. These findings explain the measured growth rates (the effective lattice mismatch was much smaller than nominal mismatch) and highlight the strong influence played by the substrate on the composition of surface precipitates in aqueous conditions.« less

Highly multiplexed and quantitative cell-surface protein profiling using genetically barcoded antibodies.

PubMed

Pollock, Samuel B; Hu, Amy; Mou, Yun; Martinko, Alexander J; Julien, Olivier; Hornsby, Michael; Ploder, Lynda; Adams, Jarrett J; Geng, Huimin; Müschen, Markus; Sidhu, Sachdev S; Moffat, Jason; Wells, James A

2018-03-13

Human cells express thousands of different surface proteins that can be used for cell classification, or to distinguish healthy and disease conditions. A method capable of profiling a substantial fraction of the surface proteome simultaneously and inexpensively would enable more accurate and complete classification of cell states. We present a highly multiplexed and quantitative surface proteomic method using genetically barcoded antibodies called phage-antibody next-generation sequencing (PhaNGS). Using 144 preselected antibodies displayed on filamentous phage (Fab-phage) against 44 receptor targets, we assess changes in B cell surface proteins after the development of drug resistance in a patient with acute lymphoblastic leukemia (ALL) and in adaptation to oncogene expression in a Myc-inducible Burkitt lymphoma model. We further show PhaNGS can be applied at the single-cell level. Our results reveal that a common set of proteins including FLT3, NCR3LG1, and ROR1 dominate the response to similar oncogenic perturbations in B cells. Linking high-affinity, selective, genetically encoded binders to NGS enables direct and highly multiplexed protein detection, comparable to RNA-sequencing for mRNA. PhaNGS has the potential to profile a substantial fraction of the surface proteome simultaneously and inexpensively to enable more accurate and complete classification of cell states. Copyright © 2018 the Author(s). Published by PNAS.

Online single particle measurement of fireworks pollution during Chinese New Year in Nanning.

PubMed

Li, Jingyan; Xu, Tingting; Lu, Xiaohui; Chen, Hong; Nizkorodov, Sergey A; Chen, Jianmin; Yang, Xin; Mo, Zhaoyu; Chen, Zhiming; Liu, Huilin; Mao, Jingying; Liang, Guiyun

2017-03-01

Time-resolved single-particle measurements were conducted during Chinese New Year in Nanning, China. Firework displays resulted in a burst of SO 2 , coarse mode, and accumulation mode (100-500nm) particles. Through single particle mass spectrometry analysis, five different types of particles (fireworks-metal, ash, dust, organic carbon-sulfate (OC-sulfate), biomass burning) with different size distributions were identified as primary emissions from firework displays. The fireworks-related particles accounted for more than 70% of the total analyzed particles during severe firework detonations. The formation of secondary particulate sulfate and nitrate during firework events was investigated on single particle level. An increase of sulfite peak (80SO 3 - ) followed by an increase of sulfate peaks (97HSO 4 - +96SO 4 - ) in the mass spectra during firework displays indicated the aqueous uptake and oxidation of SO 2 on particles. High concentration of gaseous SO 2 , high relative humidity and high particle loading likely promoted SO 2 oxidation. Secondary nitrate formed through gas-phase oxidation of NO 2 to nitric acid, followed by the condensation into particles as ammonium nitrate. This study shows that under worm, humid conditions, both primary and secondary aerosols contribute to the particulate air pollution during firework displays. Copyright © 2016. Published by Elsevier B.V.

Proof of concept for the simplified breakdown of cellulose by combining Pseudomonas putida strains with surface displayed thermophilic endocellulase, exocellulase and β-glucosidase.

PubMed

Tozakidis, Iasson E P; Brossette, Tatjana; Lenz, Florian; Maas, Ruth M; Jose, Joachim

2016-06-10

The production and employment of cellulases still represents an economic bottleneck in the conversion of lignocellulosic biomass to biofuels and other biocommodities. This process could be simplified by displaying the necessary enzymes on a microbial cell surface. Such an approach, however, requires an appropriate host organism which on the one hand can withstand the rough environment coming along with lignocellulose hydrolysis, and on the other hand does not consume the generated glucose so that it remains available for subsequent fermentation steps. The robust soil bacterium Pseudomonas putida showed a strongly reduced uptake of glucose above a temperature of 50 °C, while remaining structurally intact hence recyclable, which makes it suitable for cellulose hydrolysis at elevated temperatures. Consequently, three complementary, thermophilic cellulases from Ruminiclostridium thermocellum were displayed on the surface of the bacterium. All three enzymes retained their activity on the cell surface. A mixture of three strains displaying each one of these enzymes was able to synergistically hydrolyze filter paper at 55 °C, producing 20 μg glucose per mL cell suspension in 24 h. We could establish Pseudomonas putida as host for the surface display of cellulases, and provided proof-of-concept for a fast and simple cellulose breakdown process at elevated temperatures. This study opens up new perspectives for the application of P. putida in the production of biofuels and other biotechnological products.

Constructing MnO{sub 2}/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Weiwei; Liu, Tiangui, E-mail: tianguiliu@gmail.com; Cao, Shiyi

In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO{sub 2} nanoparticles (MnO{sub 2}/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO{sub 2} nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO{sub 2}/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancementmore » for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO{sub 2} nanoparticles. - Graphical abstract: The MnO{sub 2}/single crystalline ZnO nanorods hybrids, which MnO{sub 2} nanoparticles are loaded on the surface of ZnO nanorods, were prepared by the step-by-step precipitation method under the assistance of ammonia and hydrogen peroxide. Display Omitted - Highlights: • MnO{sub 2}/ZnO nanorod hybrids were prepared by the step-by-step assembly method. • Single crystalline ZnO nanorods can be decorated by MnO{sub 2} nanoparticles. • MnO{sub 2}/ZnO nanorod hybrids possess good photocatalytic and antibacterial activity. • MnO{sub 2} can improve the photocatalytic activity of ZnO nanorods under visible light.« less

Discovery and application of peptides that bind to proteins and solid state inorganic materials

NASA Astrophysics Data System (ADS)

Stearns, Linda A.

A series of three projects was undertaken on the theme of peptide-based molecular recognition. In the first project, a messenger RNA (mRNA) display selection was carried out against the II-VI semiconductors zinc sulfide (ZnS), zinc selenide (ZnSe), and cadmium sulfide (CdS). Sequence analysis of 18-mer semiconductor-binding peptides (SBPs) following four rounds of selection indicated that the amino acid sequences were enriched in polar residues compared to the naive library, suggesting that hydrogen-bonding interactions are a dominant mode of interaction between the SBPs and their cognate inorganic surfaces. Select peptides were expressed as fusions of the green fluorescent protein (GFP) to visualize their recognition of semiconductor crystals. Interpretation of the results was complicated by a high fluorescence background that was observed with certain control GFP fusions. Additional experiments, including cross-specificity binding assays, are needed to characterize the peptides that were isolated in this selection. A second project described the practical application of a known inorganic-binding and nucleating peptide. Peptide A3, which was previously isolated by phage display, was chemically conjugated to a short DNA strand using the heterobifunctional linker succinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (SMCC). The resulting peptide-DNA conjugate was hybridized to ten complementary single-stranded capture probes extending outward from the surface of an origami DNA nanotube. A gold precursor solution was added to initiate nucleation and growth of gold nanoparticles at the site of the peptide. Transmission electron microscopy (TEM) was used to visualize the gold nanoparticle-decorated nanostructures. This approach holds immense promise for organizing compositionally-diverse materials at the nanoscale. In a third project, a novel non-iterative approach to mRNA display called covalent capture was demonstrated. Using human transferrin as a target protein, peptides with low-nanomolar affinity were isolated from a combinatorial library of one trillion distinct 12-mer peptide sequences by using UV light to covalently crosslink the peptides to a photoreactive arm that was displayed on the protein surface. The best peptide isolated from this screen exhibited a binding affinity constant (Kd) of 3 nM, which is equivalent to some of the best peptides isolated after many rounds of traditional bead-based selection. The approach itself is general and could be applied to many different types of problems in molecular biology.

Forces in yeast flocculation

NASA Astrophysics Data System (ADS)

El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P.; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N.; Dufrêne, Yves F.

2015-01-01

In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion (``flocculation'') is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

Discovery and Development of Synthetic and Natural Biomaterials for Protein Therapeutics and Medical Device Applications

NASA Astrophysics Data System (ADS)

Keefe, Andrew J.

Controlling nonspecific protein interactions is important for applications from medical devices to protein therapeutics. The presented work is a compilation of efforts aimed at using zwitterionic (ionic yet charge neutral) polymers to modify and stabilize the surface of sensitive biomedical and biological materials. Traditionally, when modifying the surface of a material, the stability of the underlying substrate. The materials modified in this dissertation are unique due to their unconventional amorphous characteristics which provide additional challenges. These are poly(dimethyl siloxane) (PDMS) rubber, and proteins. These materials may seem dissimilar, but both have amorphous surfaces, that do not respond well to chemical modification. PDMS is a biomaterial extensively used in medical device manufacturing, but experiences unacceptably high levels of non-specific protein fouling when used with biological samples. To reduce protein fouling, surface modification is often needed. Unfortunately conventional surface modification methods, such as Poly(ethylene glycol) (PEG) coatings, do not work for PDMS due to its amorphous state. Herein, we demonstrate how a superhydrophilic zwitterionic material, poly(carboxybetaine methacrylate) (pCBMA), can provide a highly stable nonfouling coating with long term stability due to the sharp the contrast in hydrophobicity between pCBMA and PDMS. Biological materials, such as proteins, also require stabilization to improve shelf life, circulation time, and bioactivity. Conjugation of proteins with PEG is often used to increase protein stability, but has a detrimental effect on bioactivity. Here we have shown that pCBMA conjugation improves stability in a similar fashion to PEG, but also retains, or even improves, binding affinity due to enhanced protein-substrate hydrophobic interactions. Recognizing that pCBMA chemically resembles the combination of lysine (K) and glutamic acid (E) amino acids, we have shown how zwitterionic nonfouling peptides can be genetically engineered onto a protein to form recombinant protein-polymer conjugates. This technique avoids the need to post-modify proteins, that is often expensive and time consuming in protein manufacturing. Finally, we have developed two new peptide screening methods that were able to select for nonfouling peptide sequences. The selection for nonfouling sequences is not possible using traditional methods (phage display, yeast display, bacterial display and resin display) due to the presence of background interference. In our first nonfouling peptide screening method, we measured the fouling properties of peptides that were immobilized on the surface of solid glass beads. Peptides first needed to be rationally designed, and then subsequently evaluated for protein binding. Using this method, we were able to screen of 10's of sequences. Our second nonfouling peptide screening method is able to screen thousands of peptide sequences using a combinatorially generated peptide library. This was accomplished using controlled pore glass (CPG) beads as substrates to develop one-bead-one-compound (OBOC) peptide libraries. The choice of a porous substrate made it possible to synthesize enough peptide material to allow for peptide sequencing from a single bead using mass spectrometry techniques.

Purification of functional baculovirus particles from silkworm larval hemolymph and their use as nanoparticles for the detection of human prorenin receptor (PRR) binding

PubMed Central

2011-01-01

Background Baculovirus, which has a width of 40 nm and a length of 250-300 nm, can display functional peptides, receptors and antigens on its surface by their fusion with a baculovirus envelop protein, GP64. In addition, some transmembrane proteins can be displayed without GP64 fusion, using the native transmembrane domains of the baculovirus. We used this functionality to display human prorenin receptor fused with GFPuv (GFPuv-hPRR) on the surface of silkworm Bombyx mori nucleopolyhedrovirus (BmNPV) and then tested whether these baculovirus particles could be used to detect protein-protein interactions. Results BmNPV displaying GFPuv-hPRR (BmNPV-GFPuv-hPRR) was purified from hemolymph by using Sephacryl S-1000 column chromatography in the presence of 0.01% Triton X-100. Its recovery was 86% and the final baculovirus particles number was 4.98 × 108 pfu. Based on the results of enzyme-linked immunosorbent assay (ELISA), 3.1% of the total proteins in BmNPV-GFPuv-hPRR were GFPuv-hPRR. This value was similar to that calculated from the result of western blot by a densitometry (2.7%). To determine whether BmNPV-GFPuv-hPRR particles were bound to human prorenin, ELISA results were compared with those from ELISAs using protease negative BmNPV displaying β1,3-N-acetylglucosaminyltransferase 2 fused with the gene encoding GFPuv (GGT2) (BmNPV-CP--GGT2) particles, which do not display hPRR on their surfaces. Conclusion The display of on the surface of the BmNPV particles will be useful for the detection of protein-protein interactions and the screening of inhibitors and drugs in their roles as nanobioparticles. PMID:21635720

Ciliary heterogeneity within a single cell: the Paramecium model.

PubMed

Aubusson-Fleury, Anne; Cohen, Jean; Lemullois, Michel

2015-01-01

Paramecium is a single cell able to divide in its morphologically differentiated stage that has many cilia anchored at its cell surface. Many thousands of cilia are thus assembled in a short period of time during division to duplicate the cell pattern while the cell continues swimming. Most, but not all, of these sensory cilia are motile and involved in two main functions: prey capture and cell locomotion. These cilia display heterogeneity, both in their length and their biochemical properties. Thanks to these properties, as well as to the availability of many postgenomic tools and the possibility to follow the regrowth of cilia after deciliation, Paramecium offers a nice opportunity to study the assembly of the cilia, as well as the genesis of their diversity within a single cell. In this paper, after a brief survey of Paramecium morphology and cilia properties, we describe the tools and the protocols currently used for immunofluorescence, transmission electron microscopy, and ultrastructural immunocytochemistry to analyze cilia, with special recommendations to overcome the problem raised by cilium diversity. Copyright © 2015. Published by Elsevier Inc.

Identification and Single-Cell Functional Characterization of an Endodermally Biased Pluripotent Substate in Human Embryonic Stem Cells.

PubMed

Allison, Thomas F; Smith, Andrew J H; Anastassiadis, Konstantinos; Sloane-Stanley, Jackie; Biga, Veronica; Stavish, Dylan; Hackland, James; Sabri, Shan; Langerman, Justin; Jones, Mark; Plath, Kathrin; Coca, Daniel; Barbaric, Ivana; Gokhale, Paul; Andrews, Peter W

2018-05-09

Human embryonic stem cells (hESCs) display substantial heterogeneity in gene expression, implying the existence of discrete substates within the stem cell compartment. To determine whether these substates impact fate decisions of hESCs we used a GFP reporter line to investigate the properties of fractions of putative undifferentiated cells defined by their differential expression of the endoderm transcription factor, GATA6, together with the hESC surface marker, SSEA3. By single-cell cloning, we confirmed that substates characterized by expression of GATA6 and SSEA3 include pluripotent stem cells capable of long-term self-renewal. When clonal stem cell colonies were formed from GATA6-positive and GATA6-negative cells, more of those derived from GATA6-positive cells contained spontaneously differentiated endoderm cells than similar colonies derived from the GATA6-negative cells. We characterized these discrete cellular states using single-cell transcriptomic analysis, identifying a potential role for SOX17 in the establishment of the endoderm-biased stem cell state. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Dual genetically encoded phage-displayed ligands.

PubMed

Mohan, Kritika; Weiss, Gregory A

2014-05-15

M13 bacteriophage display presents polypeptides as fusions to phage coat proteins. Such phage-displayed ligands offer useful reagents for biosensors. Here, we report a modified phage propagation protocol for the consistent and robust display of two different genetically encoded ligands on the major coat protein, P8. The results demonstrate that the phage surface reaches a saturation point for maximum peptide display. Copyright © 2014 Elsevier Inc. All rights reserved.

Autodisplay: Development of an Efficacious System for Surface Display of Antigenic Determinants in Salmonella Vaccine Strains

PubMed Central

Kramer, Uwe; Rizos, Konstantin; Apfel, Heiko; Autenrieth, Ingo B.; Lattemann, Claus T.

2003-01-01

To optimize antigen delivery by Salmonella vaccine strains, a system for surface display of antigenic determinants was established by using the autotransporter secretion pathway of gram-negative bacteria. A modular system for surface display allowed effective targeting of heterologous antigens or fragments thereof to the bacterial surface by the autotransporter domain of AIDA-I, the Escherichia coli adhesin involved in diffuse adherence. A major histocompatibility complex class II-restricted epitope, comprising amino acids 74 to 86 of the Yersinia enterocolitica heat shock protein Hsp60 (Hsp6074-86), was fused to the AIDA-I autotransporter domain, and the resulting fusion protein was expressed at high levels on the cell surface of E. coli and Salmonella enterica serovar Typhimurium. Colonization studies in mice vaccinated with Salmonella strains expressing AIDA-I fusion proteins demonstrated high genetic stability of the generated vaccine strain in vivo. Furthermore, a pronounced T-cell response against Yersinia Hsp6074-86 was induced in mice vaccinated with a Salmonella vaccine strain expressing the Hsp6074-86-AIDA-I fusion protein. This was shown by monitoring Yersinia Hsp60-stimulated IFN-γ secretion and proliferation of splenic T cells isolated from vaccinated mice. These results demonstrate that the surface display of antigenic determinants by the autotransporter pathway deserves special attention regarding the application in live attenuated Salmonella vaccine strains. PMID:12654812

Autodisplay: development of an efficacious system for surface display of antigenic determinants in Salmonella vaccine strains.

PubMed

Kramer, Uwe; Rizos, Konstantin; Apfel, Heiko; Autenrieth, Ingo B; Lattemann, Claus T

2003-04-01

To optimize antigen delivery by Salmonella vaccine strains, a system for surface display of antigenic determinants was established by using the autotransporter secretion pathway of gram-negative bacteria. A modular system for surface display allowed effective targeting of heterologous antigens or fragments thereof to the bacterial surface by the autotransporter domain of AIDA-I, the Escherichia coli adhesin involved in diffuse adherence. A major histocompatibility complex class II-restricted epitope, comprising amino acids 74 to 86 of the Yersinia enterocolitica heat shock protein Hsp60 (Hsp60(74-86)), was fused to the AIDA-I autotransporter domain, and the resulting fusion protein was expressed at high levels on the cell surface of E. coli and Salmonella enterica serovar Typhimurium. Colonization studies in mice vaccinated with Salmonella strains expressing AIDA-I fusion proteins demonstrated high genetic stability of the generated vaccine strain in vivo. Furthermore, a pronounced T-cell response against Yersinia Hsp60(74-86) was induced in mice vaccinated with a Salmonella vaccine strain expressing the Hsp60(74-86)-AIDA-I fusion protein. This was shown by monitoring Yersinia Hsp60-stimulated IFN-gamma secretion and proliferation of splenic T cells isolated from vaccinated mice. These results demonstrate that the surface display of antigenic determinants by the autotransporter pathway deserves special attention regarding the application in live attenuated Salmonella vaccine strains.

Injected phage-displayed-VP28 vaccine reduces shrimp Litopenaeus vannamei mortality by white spot syndrome virus infection.

PubMed

Solís-Lucero, G; Manoutcharian, K; Hernández-López, J; Ascencio, F

2016-08-01

White spot syndrome virus (WSSV) is the most important viral pathogen for the global shrimp industry causing mass mortalities with huge economic losses. Recombinant phages are capable of expressing foreign peptides on viral coat surface and act as antigenic peptide carriers bearing a phage-displayed vaccine. In this study, the full-length VP28 protein of WSSV, widely known as potential vaccine against infection in shrimp, was successfully cloned and expressed on M13 filamentous phage. The functionality and efficacy of this vaccine immunogen was demonstrated through immunoassay and in vivo challenge studies. In ELISA assay phage-displayed VP28 was bind to Litopenaeus vannamei immobilized hemocyte in contrast to wild-type M13 phage. Shrimps were injected with 2 × 10(10) cfu animal(-1) single dose of VP28-M13 and M13 once and 48 h later intramuscularly challenged with WSSV to test the efficacy of the vaccine against the infection. All dead challenged shrimps were PCR WSSV-positive. The accumulative mortality of the vaccinated and challenged shrimp groups was significantly lower (36.67%) than the unvaccinated group (66.67%). Individual phenoloxidase and superoxide dismutase activity was assayed on 8 and 48 h post-vaccination. No significant difference was found in those immunological parameters among groups at any sampled time evaluated. For the first time, phage display technology was used to express a recombinant vaccine for shrimp. The highest percentage of relative survival in vaccinated shrimp (RPS = 44.99%) suggest that the recombinant phage can be used successfully to display and deliver VP28 for farmed marine crustaceans. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultra-high contrast retinal display system for single photoreceptor psychophysics

PubMed Central

Domdei, Niklas; Domdei, Lennart; Reiniger, Jenny L.; Linden, Michael; Holz, Frank G.; Roorda, Austin; Harmening, Wolf M.

2017-01-01

Due to the enormous dynamic range of human photoreceptors in response to light, studying their visual function in the intact retina challenges the stimulation hardware, specifically with regard to the displayable luminance contrast. The adaptive optics scanning laser ophthalmoscope (AOSLO) is an optical platform that focuses light to extremely small retinal extents, approaching the size of single photoreceptor cells. However, the current light modulation techniques produce spurious visible backgrounds which fundamentally limit experimental options. To remove unwanted background light and to improve contrast for high dynamic range visual stimulation in an AOSLO, we cascaded two commercial fiber-coupled acousto-optic modulators (AOMs) and measured their combined optical contrast. By compensating for zero-point differences in the individual AOMs, we demonstrate a multiplicative extinction ratio in the cascade that was in accordance with the extinction ratios of both single AOMs. When latency differences in the AOM response functions were individually corrected, single switch events as short as 50 ns with radiant power contrasts up to 1:1010 were achieved. This is the highest visual contrast reported for any display system so far. We show psychophysically that this contrast ratio is sufficient to stimulate single foveal photoreceptor cells with small and bright enough visible targets that do not contain a detectable background. Background-free stimulation will enable photoreceptor testing with custom adaptation lights. Furthermore, a larger dynamic range in displayable light levels can drive photoreceptor responses in cones as well as in rods. PMID:29359094

Cultured Human Adipose Tissue Pericytes and Mesenchymal Stromal Cells Display a Very Similar Gene Expression Profile

PubMed Central

Malta, Tathiane Maistro; de Deus Wagatsuma, Virgínia Mara; Palma, Patrícia Viana Bonini; Araújo, Amélia Goes; Ribeiro Malmegrim, Kelen Cristina; Morato de Oliveira, Fábio; Panepucci, Rodrigo Alexandre; Silva, Wilson Araújo; Kashima Haddad, Simone; Covas, Dimas Tadeu

2015-01-01

Mesenchymal stromal cells (MSCs) are cultured cells that can give rise to mature mesenchymal cells under appropriate conditions and secrete a number of biologically relevant molecules that may play an important role in regenerative medicine. Evidence indicates that pericytes (PCs) correspond to mesenchymal stem cells in vivo and can give rise to MSCs when cultured, but a comparison between the gene expression profiles of cultured PCs (cPCs) and MSCs is lacking. We have devised a novel methodology to isolate PCs from human adipose tissue and compared cPCs to MSCs obtained through traditional methods. Freshly isolated PCs expressed CD34, CD140b, and CD271 on their surface, but not CD146. Both MSCs and cPCs were able to differentiate along mesenchymal pathways in vitro, displayed an essentially identical surface immunophenotype, and exhibited the ability to suppress CD3+ lymphocyte proliferation in vitro. Microarray expression data of cPCs and MSCs formed a single cluster among other cell types. Further analyses showed that the gene expression profiles of cPCs and MSCs are extremely similar, although MSCs differentially expressed endothelial cell (EC)-specific transcripts. These results confirm, using the power of transcriptomic analysis, that PCs give rise to MSCs and suggest that low levels of ECs may persist in MSC cultures established using traditional protocols. PMID:26192741

Synthetic Vision Enhanced Surface Operations and Flight Procedures Rehearsal Tool

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Williams, Steven P.; Kramer, Lynda J.

2006-01-01

Limited visibility has been cited as predominant causal factor for both Controlled-Flight-Into-Terrain (CFIT) and runway incursion accidents. NASA is conducting research and development of Synthetic Vision Systems (SVS) technologies which may potentially mitigate low visibility conditions as a causal factor to these accidents while replicating the operational benefits of clear day flight operations, regardless of the actual outside visibility condition. Two experimental evaluation studies were performed to determine the efficacy of two concepts: 1) head-worn display application of SVS technology to enhance transport aircraft surface operations, and 2) three-dimensional SVS electronic flight bag display concept for flight plan preview, mission rehearsal and controller-pilot data link communications interface of flight procedures. In the surface operation study, pilots evaluated two display devices and four display modes during taxi under unlimited and CAT II visibility conditions. In the mission rehearsal study, pilots flew approaches and departures in an operationally-challenged airport environment, including CFIT scenarios. Performance using the SVS concepts was compared to traditional baseline displays with paper charts only or EFB information. In general, the studies evince the significant situation awareness and enhanced operational capabilities afforded from these advanced SVS display concepts. The experimental results and conclusions from these studies are discussed along with future directions.

Microshear bond strength of resin composite to teeth affected by molar hypomineralization using 2 adhesive systems.

PubMed

William, Vanessa; Burrow, Michael F; Palamara, Joseph E A; Messer, Louise B

2006-01-01

When restoring hypomineralized first permanent molars, placement of cavo-surface margins can be difficult to ascertain due to uncertainty of the bonding capability of the tooth surface. The purpose of this study was to investigate the adhesion of resin composite bonded to control and hypomineralized enamel with an all-etch single-bottle adhesive or self-etching primer adhesive. Specimens of control enamel (N=44) and hypomineralized enamel (N=45) had a 0.975-mm diameter composite rod (Filtek Supreme Universal Restorative) bonded with either 3M ESPE Single Bond or Clearfil SE Bond following manufacturers' instructions. Specimens were stressed in shear at 1 mm/min to failure (microshear bond strength). Etched enamel surfaces and enamel-adhesive interfaces were examined under scanning electron microscopy. The microshear bond strength (MPa) of resin composite bonded to hypomineralized enamel was significantly lower than for control enamel (3M ESPE Single Bond=7.08 +/- 4.90 vs 16.27 +/- 10.04; Clearfil SE Bond=10.39 +/- 7.56 vs 19.63 +/- 7.42; P=.001). Fractures were predominantly adhesive in control enamel and cohesive in hypomineralized enamel. Scotchbond etchant produced deep interprismatic and intercrystal porosity in control enamel and shallow etch patterns with minimal intercrystal porosity in hypomineralized enamel. Control enamel appeared almost unaffected by SE Primer; hypomineralized enamel showed shallow etching. The hypomineralized enamel-adhesive interface was porous with cracks in the enamel. The control enamel-adhesive interface displayed a hybrid layer of even thickness. The microshear bond strength of resin composite bonded to hypomineralized enamel was significantly lower than for control enamel. This was supported by differences seen in etch patterns and at the enamel-adhesive interface.

Audience perceptions of candidates' appropriateness as a function of nonverbal behaviors displayed during televised political debates.

PubMed

Seiter, John S; Weger, Harry

2005-04-01

Compared to televised debates using a single-screen format, such debates using a split screen presenting both debaters simultaneously show viewers the nonverbal reactions of each debater's opponent. The authors examined how appropriate or inappropriate such nonverbal behaviors are perceived to be. Students watched one of four versions of a televised debate. One version used a single-screen format, showing only the speaker, whereas the other three versions used a split-screen format in which the speaker's oppodent displayed constant, occasional, or no nonverbal disagreement with the speaker. Students then rated the debaters' appropriateness. Analysis indicated that the opponent was perceived to be less appropriate when he displayed any background disagreement compared to when he did not. The students perceived the speaker as most appropriate when his opponent displayed constant nonverbal disagreement.

Integrating Satellite, Radar and Surface Observation with Time and Space Matching

NASA Astrophysics Data System (ADS)

Ho, Y.; Weber, J.

2015-12-01

The Integrated Data Viewer (IDV) from Unidata is a Java™-based software framework for analyzing and visualizing geoscience data. It brings together the ability to display and work with satellite imagery, gridded data, surface observations, balloon soundings, NWS WSR-88D Level II and Level III RADAR data, and NOAA National Profiler Network data, all within a unified interface. Applying time and space matching on the satellite, radar and surface observation datasets will automatically synchronize the display from different data sources and spatially subset to match the display area in the view window. These features allow the IDV users to effectively integrate these observations and provide 3 dimensional views of the weather system to better understand the underlying dynamics and physics of weather phenomena.

Video display engineering and optimization system

NASA Technical Reports Server (NTRS)

Larimer, James (Inventor)

1997-01-01

A video display engineering and optimization CAD simulation system for designing a LCD display integrates models of a display device circuit, electro-optics, surface geometry, and physiological optics to model the system performance of a display. This CAD system permits system performance and design trade-offs to be evaluated without constructing a physical prototype of the device. The systems includes a series of modules which permit analysis of design trade-offs in terms of their visual impact on a viewer looking at a display.

Functional cell-surface display of a lipase-specific chaperone.

PubMed

Wilhelm, Susanne; Rosenau, Frank; Becker, Stefan; Buest, Sebastian; Hausmann, Sascha; Kolmar, Harald; Jaeger, Karl-Erich

2007-01-02

Lipases are important enzymes in biotechnology. Extracellular bacterial lipases from Pseudomonads and related species require the assistance of specific chaperones, designated "Lif" proteins (lipase specific foldases). Lifs, a unique family of steric chaperones, are anchored to the periplasmic side of the inner membrane where they convert lipases into their active conformation. We have previously shown that the autotransporter protein EstA from P. aeruginosa can be used to direct a variety of proteins to the cell surface of Escherichia coli. Here we demonstrate for the first time the functional cell-surface display of the Lif chaperone and FACS (fluorescence-activated cell sorting)-based analysis of bacterial cells that carried foldase-lipase complexes. The model Lif protein, LipH from P. aeruginosa, was displayed at the surface of E. coli cells. Surface exposed LipH was functional and efficiently refolded chemically denatured lipase. The foldase autodisplay system reported here can be used for a variety of applications including the ultrahigh-throughput screening of large libraries of foldase variants generated by directed evolution.

Field ion microscopic studies of the CO oxidation on platinum: Bistability and oscillations

NASA Astrophysics Data System (ADS)

Gorodetskii, V.; Drachsel, W.; Ehsasi, M.; Block, J. H.

1994-05-01

The oscillating CO oxidation is investigated on a Pt-field emitter tip by using the field ion mode of surface imaging of Oad sites with O2 as imaging gas. Based on data of the titration reactions [V. Gorodetskii, W. Drachsel, and J. H. Block, J. Chem. Phys. 100, C. E. UPDATE (1994)], external control parameters for the regions of bistability and of self-sustained isothermal oscillations could be found. On a field emitter tip, oscillations can be generated in a rather large parameter space. The anticlockwise hysteresis of O+2 ion currents in temperature cycles occurs in agreement with results on single crystal planes. Unexpected regular oscillation sequences could occasionally be obtained on the small surface areas of a field emitter tip and measured as function of the CO partial pressure and of the temperature. Different stages within oscillating cycles were documented by field ion images. Oscillations of total ion currents are correlated with variations in the spatial brightness of field ion images. In the manifold of single crystal planes of a field emitter {331} planes around the {011} regions are starting points for oscillations which mainly proceed along [100] vicinals. This excludes the {111} regions from autonomous oscillations. With slightly increased CO partial pressures fast local oscillations at a few hundred surface sites of the Pt(001) plane display short-living CO islands of 40 to 50 Å diameter. Temporal oscillations of the total O+2 ion current are mainly caused by surface plane specific spatial oscillations. The synchronization is achieved by diffusion reaction fronts rather than by gas phase synchronization.

Surface microstructure of bitumen characterized by atomic force microscopy.

PubMed

Yu, Xiaokong; Burnham, Nancy A; Tao, Mingjiang

2015-04-01

Bitumen, also called asphalt binder, plays important roles in many industrial applications. It is used as the primary binding agent in asphalt concrete, as a key component in damping systems such as rubber, and as an indispensable additive in paint and ink. Consisting of a large number of hydrocarbons of different sizes and polarities, together with heteroatoms and traces of metals, bitumen displays rich surface microstructures that affect its rheological properties. This paper reviews the current understanding of bitumen's surface microstructures characterized by Atomic Force Microscopy (AFM). Microstructures of bitumen develop to different forms depending on crude oil source, thermal history, and sample preparation method. While some bitumens display surface microstructures with fine domains, flake-like domains, and dendrite structuring, 'bee-structures' with wavy patterns several micrometers in diameter and tens of nanometers in height are commonly seen in other binders. Controversy exists regarding the chemical origin of the 'bee-structures', which has been related to the asphaltene fraction, the metal content, or the crystallizing waxes in bitumen. The rich chemistry of bitumen can result in complicated intermolecular associations such as coprecipitation of wax and metalloporphyrins in asphaltenes. Therefore, it is the molecular interactions among the different chemical components in bitumen, rather than a single chemical fraction, that are responsible for the evolution of bitumen's diverse microstructures, including the 'bee-structures'. Mechanisms such as curvature elasticity and surface wrinkling that explain the rippled structures observed in polymer crystals might be responsible for the formation of 'bee-structures' in bitumen. Despite the progress made on morphological characterization of bitumen using AFM, the fundamental question whether the microstructures observed on bitumen surfaces represent its bulk structure remains to be addressed. In addition, critical technical challenges associated with AFM characterization of bitumen surface structures are discussed, with possible solutions recommended. For future work, combining AFM with other chemical analysis tools that can generate comparable high resolution to AFM would provide an avenue to linking bitumen's chemistry to its microscopic morphological and mechanical properties and consequently benefit the efforts of developing structure-related models for bituminous materials across the different length scales. Copyright © 2015 Elsevier B.V. All rights reserved.

The B7-1 Cytoplasmic Tail Enhances Intracellular Transport and Mammalian Cell Surface Display of Chimeric Proteins in the Absence of a Linear ER Export Motif

PubMed Central

Lin, Yi-Chieh; Chen, Bing-Mae; Lu, Wei-Cheng; Su, Chien-I; Prijovich, Zeljko M.; Chung, Wen-Chuan; Wu, Pei-Yu; Chen, Kai-Chuan; Lee, I-Chiao; Juan, Ting-Yi; Roffler, Steve R.

2013-01-01

Membrane-tethered proteins (mammalian surface display) are increasingly being used for novel therapeutic and biotechnology applications. Maximizing surface expression of chimeric proteins on mammalian cells is important for these applications. We show that the cytoplasmic domain from the B7-1 antigen, a commonly used element for mammalian surface display, can enhance the intracellular transport and surface display of chimeric proteins in a Sar1 and Rab1 dependent fashion. However, mutational, alanine scanning and deletion analysis demonstrate the absence of linear ER export motifs in the B7 cytoplasmic domain. Rather, efficient intracellular transport correlated with the presence of predicted secondary structure in the cytoplasmic tail. Examination of the cytoplasmic domains of 984 human and 782 mouse type I transmembrane proteins revealed that many previously identified ER export motifs are rarely found in the cytoplasmic tail of type I transmembrane proteins. Our results suggest that efficient intracellular transport of B7 chimeric proteins is associated with the structure rather than to the presence of a linear ER export motif in the cytoplasmic tail, and indicate that short (less than ~ 10-20 amino acids) and unstructured cytoplasmic tails should be avoided to express high levels of chimeric proteins on mammalian cells. PMID:24073236

Is fault surface roughness indicative of fault mechanisms? Observations from experimental Limestone faults

NASA Astrophysics Data System (ADS)

Sagy, A.; Tesei, T.; Collettini, C.

2016-12-01

Geometrical irregularity of contacting surfaces is a fundamental factor controlling friction and energy dissipation during sliding. We performed direct shear experiments on 20x20 cm limestone surfaces by applying constant normal load (40-200 kN) and sliding velocity 1-300 µm/s. Before shearing, the surfaces were polished with maximal measured amplitudes of less than 0.1 mm. After shear, elongated islands of shear zones are observed, characterized by grooves ploughed into the limestone surfaces and by layers of fine grain wear. These structures indicate that the contact areas during shear are scattered and occupy a limited portion of the entire surface area. The surfaces was scanned by a laser profilometer that measures topography using 640 parallel beams in a single run, offer up to 10 µm accuracy and working ranges of 200 mm. Two distinctive types of topographical end members are defined: rough wavy sections and smooth polished ones. The rough zones display ridges with typical amplitudes of 0.1-1 mm that cross the grooves perpendicular to the slip direction. These features are associated with penetrative brittle damage and with fragmentation. The smoother zones display reflective mirror-like surfaces bordered by topographical sharp steps at heights of 0.3-0.5 mm. These sections are localized inside the wear layer or between the wear layer and the host rock, and are not associated with observed penetrative damage. Preliminary statistical analysis suggests that the roughness of the ridges zones can be characterized using a power-low relationship between profile length and mean roughness, with relatively high values of Hurst exponents (e.g. H > 0.65) parallel to the slip direction. The polished zones, on the other hand, corresponded to lower values of Hurst exponents (e.g. H ≤ 0.6). Both structural and roughness measurements indicate that the distinctive topographic variations on the surfaces reflect competing mechanical processes which occur simultaneously during shear. The wavy ridged zone is the surface expression of penetrative cracking and fragmentation which widen the shear zone, while the smooth zones reflect localized flow and plastic deformation of the wear material. The similarity in topography of shear structures between experimental and natural faults suggests similar mechanical processes.

Surface display of synthetic phytochelatins on Saccharomyces cerevisiae for enhanced ethanol production in heavy metal-contaminated substrates.

PubMed

Yang, Chi-En; Chu, I-Ming; Wei, Yu-Hong; Tsai, Shen-Long

2017-12-01

The aim of this work was to study the feasibility of surface displaying synthetic phytochelatin (EC) on Saccharomyces cerevisiae to overcome the inhibitory effect of heavy metals on ethanol production. Via the fusion of a gene encoding EC to an α-agglutinin gene, the engineered S. cerevisiae was able to successfully display EC on its surface. This surface engineered yeast strain exhibited an efficient cadmium adsorption capability and a remarkably enhanced cadmium tolerance. Moreover, its ethanol production efficiency was significantly improved as compared to a control strain in the presence of cadmium. Similar results could also be observed in the presence of other metals, such as nickel, lead and copper. Overall, this method allows simultaneous biorefinery and heavy metal removal when using heavy metal-contaminated biomass as raw materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

A two-dimensional ACAR study of untwinned YBa2Cu3O(7-x)

NASA Astrophysics Data System (ADS)

Smedskjaer, L. C.; Bansil, A.

1991-12-01

We have carried out 2D-ACAR measurements on an untwinned single crystal of YBa2Cu3O(sub 7-x) as a function of temperature, for five temperatures ranging from 30K to 300K. We show that these temperature-dependent 2D-ACAR spectra can be described to a good approximation as a superposition of two temperature independent spectra with temperature-dependent weighting factors. We show further how the data can be used to correct for the 'background' in the experimental spectrum. Such a 'background corrected' spectrum is in remarkable accord with the corresponding band theory predictions, and displays, in particular, clear signatures of the electron ridge Fermi surface.

Functional display of family 11 endoxylanases on the surface of phage M13.

PubMed

Beliën, T; Hertveldt, K; Van den Brande, K; Robben, J; Van Campenhout, S; Volckaert, G

2005-02-09

Two family 11 endoxylanases (EC 3.2.1.8) were functionally displayed on the surface of bacteriophage M13. The genes encoding endo-1,4-xylanase I from Aspergillus niger (ExlA) and endo-1,4-xylanase A from Bacillus subtilis (XynA) were fused to the gene encoding the minor coat protein g3p in phagemid vector pHOS31. Phage rescue resulted in functional monovalent display of the enzymes as was demonstrated by three independent tests. Firstly, purified recombinant phage particles showed a clear hydrolytic activity in an activity assay based on insoluble, chromagenic arabinoxylan substrate. Secondly, specific binding of endoxylanase displaying phages to immobilized endoxylanase inhibitors was demonstrated by interaction ELISA. Finally, two rounds of selection and amplification in a biopanning procedure against immobilized endoxylanase inhibitor were performed. Phages displaying endoxylanases were strongly enriched from background phages displaying unrelated proteins. These results open perspectives to use phage display for analysing protein-protein interactions at the interface between endoxylanases and their inhibitors. In addition, this technology should enable engineering of endoxylanases into novel variants with altered binding properties towards endoxylanase inhibitors.

Surface display of PbrR on Escherichia coli and evaluation of the bioavailability of lead associated with engineered cells in mice.

PubMed

Hui, Changye; Guo, Yan; Zhang, Wen; Gao, Chaoxian; Yang, Xueqin; Chen, Yuting; Li, Limei; Huang, Xianqing

2018-04-09

Human exposure to lead mainly occurs by ingestion of contaminated food, water and soil. Blocking lead uptake in the gastrointestinal tract is a novel prevention strategy. Whole-cell biosorbent for lead was constructed with PbrR genetically engineered on the cell surface of Escherichia coli (E. coli), a predominant strain among intestinal microflora, using lipoprotein (Lpp)-OmpA as the anchoring protein. In vitro, the PbrR displayed cells had an enhanced ability for immobilizing toxic lead(II) ions from the external media at both acidic and neutral pH, and exhibited a higher specific adsorption for lead compared to other physiological two valence metal ions. In vivo, the persistence of recombinant E. coli in the murine intestinal tract and the integrity of surface displayed PbrR were confirmed. In addition, oral administration of surface-engineered E. coli was safe in mice, in which the concentrations of physiological metal ions in blood were not affected. More importantly, lead associated with PbrR-displayed E. coli was demonstrated to be less bioavailable in the experimental mouse model with exposure to oral lead. This is reflected by significantly lower blood and femur lead concentrations in PbrR-displayed E. coli groups compared to the control. These results open up the possibility for the removal of toxic metal ions in vivo using engineered microorganisms as adsorbents.

Detection of fecal contamination on beef meat surfaces using handheld fluorescence imaging device (HFID)

NASA Astrophysics Data System (ADS)

Oh, Mirae; Lee, Hoonsoo; Cho, Hyunjeong; Moon, Sang-Ho; Kim, Eun-Kyung; Kim, Moon S.

2016-05-01

Current meat inspection in slaughter plants, for food safety and quality attributes including potential fecal contamination, is conducted through by visual examination human inspectors. A handheld fluorescence-based imaging device (HFID) was developed to be an assistive tool for human inspectors by highlighting contaminated food and food contact surfaces on a display monitor. It can be used under ambient lighting conditions in food processing plants. Critical components of the imaging device includes four 405-nm 10-W LEDs for fluorescence excitation, a charge-coupled device (CCD) camera, optical filter (670 nm used for this study), and Wi-Fi transmitter for broadcasting real-time video/images to monitoring devices such as smartphone and tablet. This study aimed to investigate the effectiveness of HFID in enhancing visual detection of fecal contamination on red meat, fat, and bone surfaces of beef under varying ambient luminous intensities (0, 10, 30, 50 and 70 foot-candles). Overall, diluted feces on fat, red meat and bone areas of beef surfaces were detectable in the 670-nm single-band fluorescence images when using the HFID under 0 to 50 foot-candle ambient lighting.

Negative differential resistance by molecular resonant tunneling between neutral tribenzosubporphine anchored to a Au(111) surface and tribenzosubporphine cation adsorbed on to a tungsten tip.

PubMed

Majima, Yutaka; Ogawa, Daisuke; Iwamoto, Masachika; Azuma, Yasuo; Tsurumaki, Eiji; Osuka, Atsuhiro

2013-09-25

Tribenzosubporphyrins are boron(III)-chelated triangular bowl-shaped ring-contracted porphyrins that possess a 14π-aromatic circuit. Their flat molecular shapes and discrete molecular orbital diagrams make them ideal for observation by scanning tunneling microscopy (STM). Expanding their applications toward single molecule-based devices requires a fundamental knowledge of single molecular conductance between tribenzosubporphines and the STM metal tip. We utilized a tungsten (W) STM tip to investigate the electronic properties of B-(5-mercaptopentoxy)tribenzosubporphine 1 at the single molecular level. B-(5-mercaptopentoxy)-tribenzosubporphine 1 was anchored to the Au(111) surface via reaction with 1-heptanethiol linkers that were preorganized as a self-assembled monolayer (C7S SAM) on the Au(111) substrate. This arrangement ensured that 1 was electronically decoupled from the metal surface. Differential conductance (dI/dV - V) measurements with the bare W tip exhibited a broad gap region of low conductance and three distinct responses at 2.4,-1.3, and -2.1 V. Bias-voltage-dependent STM imaging of 1 at 65 K displayed a triangle shape at -2.1 < V < -1.3 V and a circle shape at V < -2.1 V, reflecting its HOMO and HOMO-1, respectively. In addition, different conductance behaviors were reproducibly observed, which has been ascribed to the adsorption of a tribenzosubporphine-cation on the W tip. When using a W tip doped with preadsorbed tribenzosubporphine-cation, negative differential resistance (NDR) phenomena were clearly observed in a reproducible manner with a peak-to-valley ratio of 2.6, a value confirmed by spatial mapping conductance measurements. Collectively, the observed NDR phenomena have been attributed to effective molecular resonant tunneling between a neutral tribenzosubporphine anchored to the metal surface and a tribenzosubporphine cation adsorbed on a W tip.

Math on a Sphere: Making Use of Public Displays in Education

ERIC Educational Resources Information Center

Eisenberg, Michael; Basman, Antranig; Hsi, Sherry

2013-01-01

Science on a Sphere (SoS) is a compelling educational display installed at numerous museums and planetariums around the world; essentially the SoS display is a large spherical surface on which multicolor high-resolution depictions of (e.g.) planetary weather maps may be depicted. Fascinating as the SoS display is, however, it is in practice…

Surface display of bacterial tyrosinase on spores of Bacillus subtilis using CotE as an anchor protein.

PubMed

Hosseini-Abari, Afrouzossadat; Kim, Byung-Gee; Lee, Sang-Hyuk; Emtiazi, Giti; Kim, Wooil; Kim, June-Hyung

2016-12-01

Tyrosinases, copper-containing monooxygenases, are widely used enzymes for industrial, medical, and environmental applications. We report the first functional surface display of Bacillus megaterium tyrosinase on Bacillus subtilis spores using CotE as an anchor protein. Flow Cytometry was used to verify surface expression of tyrosinase on the purified spores. Moreover, tyrosinase activity of the displayed enzyme on B. subtilis spores was monitored in the presence of L-tyrosine (substrate) and CuSO 4 (inducer). The stability of the spore-displayed tyrosinase was then evaluated after 15 days maintenance of the spores at room temperature, and no significant decrease in the enzyme activity was observed. In addition, the tyrosinase-expressing spores could be repeatedly used with 62% retained enzymatic activity after six times washing with Tris-HCl buffer. This genetically immobilized tyrosinase on the spores would make a new advance in industrial, medical, and environmental applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flight Demonstration of Integrated Airport Surface Technologies for Increased Capacity and Safety

NASA Technical Reports Server (NTRS)

Jones, Denise R.; Young, Steven D.; Wills, Robert W.; Smith, Kathryn A.; Shipman, Floyd S.; Bryant, Wayne H.; Eckhardt, Dave E., Jr.

1998-01-01

A flight demonstration was conducted to address airport surface movement area capacity and safety issues by providing pilots with enhanced situational awareness information. The demonstration presented an integration of several technologies to government and industry representatives. These technologies consisted of an electronic moving map display in the cockpit, a Differential Global Positioning system (DGPS) receiver, a high speed very high frequency (VHF) data link, an Airport Surface Detection Equipment (ASDE-3) radar, and the Airport Movement Area Safety System (AMASS). Aircraft identification was presented to an air traffic controller on an AMASS display. The onboard electronic map included the display of taxi routes, hold instructions, and clearances, which were sent to the aircraft via data link by the controller. The map also displayed the positions of other traffic and warning information, which were sent to the aircraft automatically from the ASDE-3/AMASS system. This paper describes the flight demonstration in detail, along with test results.

Engineering T7 bacteriophage as a potential DNA vaccine targeting delivery vector.

PubMed

Xu, Hai; Bao, Xi; Wang, Yiwei; Xu, Yue; Deng, Bihua; Lu, Yu; Hou, Jibo

2018-03-20

DNA delivery with bacteriophage by surface-displayed mammalian cell penetrating peptides has been reported. Although, various phages have been used to facilitate DNA transfer by surface displaying the protein transduction domain of human immunodeficiency virus type 1 Tat protein (Tat peptide), no similar study has been conducted using T7 phage. In this study, we engineeredT7 phage as a DNA targeting delivery vector to facilitate cellular internalization. We constructed recombinant T7 phages that displayed Tat peptide on their surface and carried eukaryotic expression box (EEB) as a part of their genomes (T7-EEB-Tat). We demonstrated that T7 phage harboring foreign gene insertion had packaged into infective progeny phage particles. Moreover, when mammalian cells that were briefly exposed to T7-EEB-Tat, expressed a significant higher level of the marker gene with the control cells infected with the wide type phage without displaying Tat peptides. These data suggested that the potential of T7 phage as an effective delivery vector for DNA vaccine transfer.

Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

PubMed Central

Fulati, Alimujiang; Ali, Syed M.Usman; Riaz, Muhammad; Amin, Gul; Nur, Omer; Willander, Magnus

2009-01-01

ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells. PMID:22291545

Self-addressed diffractive lens schemes for the characterization of LCoS displays

NASA Astrophysics Data System (ADS)

Zhang, Haolin; Lizana, Angel; Iemmi, Claudio; Monroy-Ramírez, Freddy A.; Marquez, Andrés.; Moreno, Ignacio; Campos, Juan

2018-02-01

We proposed a self-calibration method to calibrate both the phase-voltage look-up table and the screen phase distribution of Liquid Crystal on Silicon (LCoS) displays by implementing different lens configurations on the studied device within a same optical scheme. On the one hand, the phase-voltage relation is determined from interferometric measurements, which are obtained by addressing split-lens phase distributions on the LCoS display. On the other hand, the surface profile is retrieved by self-addressing a diffractive micro-lens array to the LCoS display, in a way that we configure a Shack-Hartmann wavefront sensor that self-determines the screen spatial variations. Moreover, both the phase-voltage response and the surface phase inhomogeneity of the LCoS are measured within the same experimental set-up, without the necessity of further adjustments. Experimental results prove the usefulness of the above-mentioned technique for LCoS displays characterization.

Surface display of Salmonella epitopes in Escherichia coli and Staphylococcus carnosus.

PubMed

Nhan, Nguyen Thanh; Gonzalez de Valdivia, Ernesto; Gustavsson, Martin; Hai, Truong Nam; Larsson, Gen

2011-04-11

Salmonella enterica serotype Enteritidis (SE) is considered to be one of the most potent pathogenic Salmonella serotypes causing food-borne disease in humans. Since a live bacterial vaccine based on surface display of antigens has many advantages over traditional vaccines, we have studied the surface display of the SE antigenic proteins, H:gm and SefA in Escherichia coli by the β-autotransporter system, AIDA. This procedure was compared to protein translocation in Staphylococcus carnosus, using a staphylococci hybrid vector earlier developed for surface display of other vaccine epitopes. Both SefA and H:gm were translocated to the outer membrane in Escherichia coli. SefA was expressed to full length but H:gm was shorter than expected, probably due to a proteolytic cleavage of the N-terminal during passage either through the periplasm or over the membrane. FACS analysis confirmed that SefA was facing the extracellular environment, but this could not be conclusively established for H:gm since the N-terminal detection tag (His6) was cleaved off. Polyclonal salmonella antibodies confirmed the sustained antibody-antigen binding towards both proteins. The surface expression data from Staphylococcus carnosus suggested that the H:gm and SefA proteins were transported to the cell wall since the detection marker was displayed by FACS analysis. Apart from the accumulated knowledge and the existence of a wealth of equipment and techniques, the results indicate the selection of E. coli for further studies for surface expression of salmonella antigens. Surface expression of the full length protein facing the cell environment was positively proven by standard analysis, and the FACS signal comparison to expression in Staphylococcus carnosus shows that the distribution of the surface protein on each cell was comparatively very narrow in E. coli, the E. coli outer membrane molecules can serve as an adjuvant for the surface antigenic proteins and multimeric forms of the SefA protein were detected which would probably be positive for the realisation of a strong antigenic property. The detection of specific and similar proteolytic cleavage patterns for both the proteins provides a further starting point for the investigation and development of the Escherichia coli AIDA autotransporter efficiency.

Evidence of extensive diversity in bacterial adherence mechanisms that exploit unanticipated stainless steel surface structural complexity for biofilm formation.

PubMed

Davis, Elisabeth M; Li, Dongyang; Shahrooei, Mohammad; Yu, Bin; Muruve, Daniel; Irvin, Randall T

2013-04-01

Three protease-resistant bioorganic 304 stainless steel surfaces were created through the reaction of synthetic peptides consisting of the D-enantiomeric isomer (D-K122-4), the retro-inverso D-enantiomeric isomer (RI-K122-4), and a combination of the two peptides (D+RI) of the Pseudomonas aeruginosa PilA receptor binding domain with steel surfaces. The peptides used to produce the new materials differ only in handedness of their three-dimensional structure, but they reacted with the steel to yield materials that differed in their surface electron work function (EWF) while displaying an identical chemical composition and equivalent surface adhesive force properties. These surfaces allowed for an assessment of the relative role of surface EWF in initial biofilm formation. We examined the ability of various bacteria (selected strains of Listeria monocytogenes, L. innocua, Staphylococcus aureus and S. epidermidis) to initiate biofilm formation. The D-K1224 generated surface displayed the lowest EWF (classically associated with greater molecular interactions and more extensive biofilm formation) but was observed to be least effectively colonized by bacteria (>50% decrease in bacterial adherence of all strains). The highest surface EWF with the lowest surface free energy (RI-K122-4 generated) was more extensively colonized by bacteria, with the binding of some strains being equivalent to unmodified steel. The D+RI generated surface was least effective in minimizing biofilm formation, where some strains displayed enhanced bacterial colonization. Fluorescent microscopy revealed that the D and RI peptides displayed similar but clearly different binding patterns, suggesting that the peptides recognized different sites on the steel, and that differential binding of the peptides to the steel surfaces influences the binding of different bacterial strains and species. We have demonstrated that stainless steel surfaces can be easily modified by peptides to generate surfaces with new physiochemical properties. The D-K122-4-modified surface substantially decreases biofilm formation compared to the RI-K122-4 and D+RI surfaces. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Halftoning method for the generation of motion stimuli

NASA Technical Reports Server (NTRS)

Mulligan, Jeffrey B.; Stone, Leland S.

1989-01-01

This paper describes a novel computer-graphic technique for the generation of a broad class of motion stimuli for vision research, which uses color table animation in conjunction with a single base image. Using this technique, contrast and temporal frequency can be varied with a negligible amount of computation, once a single-base image is produced. Since only two-bit planes are needed to display a single drifting grating, an eight-bit/pixel display can be used to generate four-component plaids, in which each component of the plaid has independently programmable contrast and temporal frequency. Because the contrast and temporal frequencies of the various components are mutually independent, a large number of two-dimensional stimulus motions can be produced from a single image file.

The Role of Remote Sensing Displays in Earth Climate and Planetary Atmospheric Research

NASA Technical Reports Server (NTRS)

DelGenio, Anthony D.; Hansen, James E. (Technical Monitor)

2001-01-01

The communities of scientists who study the Earth's climate and the atmospheres of the other planets barely overlap, but the types of questions they pose and the resulting implications for the use and interpretation of remote sensing data sets have much in common. Both seek to determine the characteristic behavior of three-dimensional fluids that also evolve in time. Climate researchers want to know how and why the general patterns that define our climate today might be different in the next century. Planetary scientists try to understand why circulation patterns and clouds on Mars, Venus, or Jupiter are different from those on Earth. Both disciplines must aggregate large amounts of data covering long time periods and several altitudes to have a representative picture of the rapidly changing atmosphere they are studying. This emphasis separates climate scientists from weather forecasters, who focus at any one time on a limited number of images. Likewise, it separates planetary atmosphere researchers from planetary geologists, who rely primarily on single images (or mosaics of images covering the globe) to study two-dimensional planetary surfaces that are mostly static over the duration of a spacecraft mission yet reveal dynamic processes acting over thousands to millions of years. Remote sensing displays are usually two-dimensional projections that capture an atmosphere at an instant in time. How scientists manipulate and display such data, how they interpret what they see, and how they thereby understand the physical processes that cause what they see, are the challenges I discuss in this chapter. I begin by discussing differences in how novices and experts in the field relate displays of data to the real world. This leads to a discussion of the use and abuse of image enhancement and color in remote sensing displays. I then show some examples of techniques used by scientists in climate and planetary research to both convey information and design research strategies using remote sensing displays.

Rapid turn-around mapping of wildfires and disasters with airborne infrared imagery fro the new FireMapper® 2.0 and Oilmapper systems

Treesearch

James W. Hoffman; Lloyd L. Coulter; Philip J Riggan

2005-01-01

The new FireMapper® 2.0 and OilMapper airborne, infrared imaging systems operate in a "snapshot" mode. Both systems feature the real time display of single image frames, in any selected spectral band, on a daylight readable tablet PC. These single frames are displayed to the operator with full temperature calibration in color or grayscale renditions. A rapid...

Performance evaluation of a kinesthetic-tactual display

NASA Technical Reports Server (NTRS)

Jagacinski, R. J.; Flach, J. M.; Gilson, R. D.; Dunn, R. S.

1982-01-01

Simulator studies demonstrated the feasibility of using kinesthetic-tactual (KT) displays for providing collective and cyclic command information, and suggested that KT displays may increase pilot workload capability. A dual-axis laboratory tracking task suggested that beyond reduction in visual scanning, there may be additional sensory or cognitive benefits to the use of multiple sensory modalities. Single-axis laboratory tracking tasks revealed performance with a quickened KT display to be equivalent to performance with a quickened visual display for a low frequency sum-of-sinewaves input. In contrast, an unquickened KT display was inferior to an unquickened visual display. Full scale simulator studies and/or inflight testing are recommended to determine the generality of these results.

Controlled assembly of high-order nanoarray metal structures on bulk copper surface by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Qin, Wanwan; Yang, Jianjun

2017-07-01

We report a new one-step maskless method to fabricate high-order nanoarray metal structures comprising periodic grooves and particle chains on a single-crystal Cu surface using femtosecond laser pulses at the central wavelength of 400 nm. Remarkably, when a circularly polarized infrared femtosecond laser pulse (spectrally centered at 800 nm) pre-irradiates the sample surface, the geometric dimensions of the composite structure can be well controlled. With increasing the energy fluence of the infrared laser pulse, both the groove width and particle diameter are observed to reduce, while the measured spacing-to-diameter ratio of the nanoparticles tends to present an increasing tendency. A physical scenario is proposed to elucidate the underlying mechanisms: as the infrared femtosecond laser pulse pre-irradiates the target, the copper surface is triggered to display anomalous transient physical properties, on which the subsequently incident Gaussian blue laser pulse is spatially modulated into fringe-like energy depositions via the excitation of ultrafast surface plasmon. During the following relaxation processes, the periodically heated thin-layer regions can be transferred into the metastable liquid rivulets and then they break up into nanodroplet arrays owing to the modified Rayleigh-like instability. This investigation indicates a simple integrated approach for active designing and large-scale assembly of complexed functional nanostructures on bulk materials.

Nucleation and Epitaxy-Mediated Phase Transformation of a Precursor Cadmium Carbonate Phase at the Calcite/Water Interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riechers, Shawn L.; Rosso, Kevin M.; Kerisit, Sebastien N.

Mineral nucleation can be catalyzed by the presence of mineral substrates; however, the mechanisms of heterogeneous nucleation remain poorly understood. A combination of in situ time-sequenced measurements and nano-manipulation experiments were performed using atomic force microscopy (AFM) to probe the mechanisms of heteroepitaxial nucleation of otavite (CdCO3) on calcite (CaCO3) single crystals that exposed the (10-14) surface. Otavite and calcite are isostructural carbonates that display a 4% lattice mismatch, based on their (10-14) surface areas. AFM observations revealed a two-stage process in the nucleation of cadmium carbonate surface precipitates. As evidenced by changes in height, shape, growth behavior, and frictionmore » signal of the precipitates, a precursor phase was observed to initially form on the surface and subsequently undergo an epitaxy-mediated phase transformation to otavite, which then grew epitaxially. Nano-manipulation experiments, in which the applied force was increased progressively until precipitates were removed from the surface, showed that adhesion of the precursor phase to the substrate was distinctively weaker than that of the epitaxial phase, consistent with that of an amorphous phase. These findings demonstrate for the first time that heterogeneous mineral nucleation can follow a non-classical pathway like that found in homogenous aqueous conditions.« less

Quaternary ammonium salts substituted by 5-phenyl-1,3,4-oxadiazole-2-thiol as novel antibacterial agents with low cytotoxicity.

PubMed

Wang, Chun-Hua; Xie, Xian-Rui; Liu, Wen-Shuai; Hou, Gui-Ge; Sun, Ju-Feng; Zhao, Feng; Cong, Wei; Li, Hong-Juan; Xin, Wen-Yu

2017-11-01

Twenty-one novel 5-phenyl-1,3,4-oxadiazole-2-thiol (POT) substituted N-hydroxyethyl quaternary ammonium salts (6a-g, 7a-g, 8a-g) were prepared and characterized by FTIR, NMR, and elemental analysis. Compounds 6a, 6c, and 8a were confirmed by X-ray single-crystal diffraction. They display the unsurpassed antibacterial activity against Staphylococcus aureus, α-H-tococcus, Escherichia coli, P. aeruginosa, Proteus vulgaris, Canidia Albicans, especially 6g, 7g, 8g with dodecyl group. Compounds 8a-d with N,N-dihydroxyethyl and POT groups display unsurpassed antibacterial activity and non-toxicity. The structure-activity relationships indicate that POT and flexible dihydroxyethyl group in QAS are necessary for antibacterial activity and cytotoxicity. SEM and TEM images of E. coli morphologies of 8d show the antibacterial agents can adhere to membrane surfaces to inhibit bacterial growth by disrupting peptidoglycan formation and releasing bacterial cytoplasm from cell membranes. © 2017 John Wiley & Sons A/S.

Humidity-enhanced sub-ppm sensitivity to ammonia of covalently functionalized single-wall carbon nanotube bundle layers

NASA Astrophysics Data System (ADS)

Rigoni, F.; Freddi, S.; Pagliara, S.; Drera, G.; Sangaletti, L.; Suisse, J.-M.; Bouvet, M.; Malovichko, A. M.; Emelianov, A. V.; Bobrinetskiy, I. I.

2017-06-01

A low-cost method for carbon nanotubes (CNTs) network production from solutions on flexible polyethylene naphthalate substrates has been adopted to prepare high quality and well characterized SWCNT bundle layers to be used as the active layer in chemiresistor gas sensors. Two types of SWCNTs have been tested: pristine SWCNTs, deposited from a surfactant solution, and covalently functionalized SWCNTs, deposited from a dimethyl-acetamide solution. The humidity effects on the sensitivity of the SWCNTs network to NH3 have been investigated. The results show that relative humidity favors the response to NH3, confirming recent theoretical predictions. The COOH-functionalized sample displays the largest response owing to both its hydrophilic nature, favoring the interaction with H2O molecules, and its largest surface area. Compared to data available in the literature, the present sensors display a remarkable sensitivity well below the ppm range, which makes them quite promising for environmental and medical applications, where NH3 concentrations (mostly of the order of tens of ppb) have to be detected.

Diversity in recognition of glycans by F-type lectins and galectins: molecular, structural, and biophysical aspects

PubMed Central

Vasta, Gerardo R.; Ahmed, Hafiz; Bianchet, Mario A.; Fernández-Robledo, José A.; Amzel, L. Mario

2013-01-01

Although lectins are “hard-wired” in the germline, the presence of tandemly arrayed carbohydrate recognition domains (CRDs), of chimeric structures displaying distinct CRDs, of polymorphic genes resulting in multiple isoforms, and in some cases, of a considerable recognition plasticity of their carbohydrate binding sites, significantly expand the lectin ligand-recognition spectrum and lectin functional diversification. Analysis of structural/functional aspects of galectins and F-lectins—the most recently identified lectin family characterized by a unique CRD sequence motif (a distinctive structural fold) and nominal specificity for l-Fuc—has led to a greater understanding of self/nonself recognition by proteins with tandemly arrayed CRDs. For lectins with a single CRD, however, recognition of self and nonself glycans can only be rationalized in terms of protein oligomerization and ligand clustering and presentation. Spatial and temporal changes in lectin expression, secretion, and local concentrations in extracellular microenvironments, as well as structural diversity and spatial display of their carbohydrate ligands on the host or microbial cell surface, are suggestive of a dynamic interplay of their recognition and effector functions in development and immunity. PMID:22973821

Pilot Preferences for Information Provided and Its Format for Status, Alerts, and Controls

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.

2004-01-01

With the increased use of cathode ray tubes (CRTs) in flight decks and the computing power available, it is possible to combine status screens, alerts/procedures screens, and control screens onto a single display. This report presents the results of a survey designed to assess the perceived helpfulness and need of various pieces of information that could be included on status and control screens. The results from the survey indicate that operators want parameter ranges that change depending on the current aircraft configuration shown on bow-tie or dial displays. These displays should show the current value, normal range, alert type and range, and predictive information. Respondents wanted to see system relationships to one another for both component control and menu selection. When bringing up these various displays, this information should come up with a single button push. Finally, checklists should sense when a component has changed to the desired state.

A comparison of visual and kinesthetic-tactual displays for compensatory tracking

NASA Technical Reports Server (NTRS)

Jagacinski, R. J.; Flach, J. M.; Gilson, R. D.

1983-01-01

Recent research on manual tracking with a kinesthetic-tactual (KT) display suggests that under certain conditions it can be an effective alternative or supplement to visual displays. In order to understand better how KT tracking compares with visual tracking, both a critical tracking and stationary single-axis tracking tasks were conducted with and without velocity quickening. In the critical tracking task, the visual displays were superior, however, the quickened KT display was approximately equal to the unquickened visual display. In stationary tracking tasks, subjects adopted lag equalization with the quickened KT and visual displays, and mean-squared error scores were approximately equal. With the unquickened displays, subjects adopted lag-lead equalization, and the visual displays were superior. This superiority was partly due to the servomotor lag in the implementation of the KT display and partly due to modality differences.

Seamless tiled display system

NASA Technical Reports Server (NTRS)

Dubin, Matthew B. (Inventor); Larson, Brent D. (Inventor); Kolosowsky, Aleksandra (Inventor)

2006-01-01

A modular and scalable seamless tiled display apparatus includes multiple display devices, a screen, and multiple lens assemblies. Each display device is subdivided into multiple sections, and each section is configured to display a sectional image. One of the lens assemblies is optically coupled to each of the sections of each of the display devices to project the sectional image displayed on that section onto the screen. The multiple lens assemblies are configured to merge the projected sectional images to form a single tiled image. The projected sectional images may be merged on the screen by magnifying and shifting the images in an appropriate manner. The magnification and shifting of these images eliminates any visual effect on the tiled display that may result from dead-band regions defined between each pair of adjacent sections on each display device, and due to gaps between multiple display devices.

Isolation of anti-toxin single domain antibodies from a semi-synthetic spiny dogfish shark display library.

PubMed

Liu, Jinny L; Anderson, George P; Goldman, Ellen R

2007-11-19

Shark heavy chain antibody, also called new antigen receptor (NAR), consists of one single Variable domain (VH), containing only two complementarity-determining regions (CDRs). The antigen binding affinity and specificity are mainly determined by these two CDRs. The good solubility, excellent thermal stability and complex sequence variation of small single domain antibodies (sdAbs) make them attractive alternatives to conventional antibodies. In this report, we construct and characterize a diversity enhanced semi-synthetic NAR V display library based on naturally occurring NAR V sequences. A semi-synthetic shark sdAb display library with a complexity close to 1e9 was constructed. This was achieved by introducing size and sequence variations in CDR3 using randomized CDR3 primers of three different lengths. Binders against three toxins, staphylococcal enterotoxin B (SEB), ricin, and botulinum toxin A (BoNT/A) complex toxoid, were isolated from panning the display library. Soluble sdAbs from selected binders were purified and evaluated using direct binding and thermal stability assays on the Luminex 100. In addition, sandwich assays using sdAb as the reporter element were developed to demonstrate their utility for future sensor applications. We demonstrated the utility of a newly created hyper diversified shark NAR displayed library to serve as a source of thermal stable sdAbs against a variety of toxins.

AOPA Survey Summary of AGATE Concepts Demonstration October 17-19, 1996. Volume 1; Basic Report

NASA Technical Reports Server (NTRS)

1997-01-01

An AGATE Concepts Demonstration was conducted at the Annual Aircraft Owners and Pilots Association (AOPA) Convention in 1996. The demonstration consisted of an interactive simulation of a single-pilot, single-engine aircraft in which the participant took off, flew a brief enroute segment and then flew a Global Positioning System (GPS) approach and landing. The participant was provided an advanced 'pathway-in-the-sky' presentation on both a head-up display and a head-down display to follow throughout the flight. A single lever power control and display concept was also provided for control of the engine throughout the flight. A second head-down, multifunction display in the instrument panel provided a moving map display for navigation purposes and monitoring of the status of the aircraft's systems. An estimated 352 people observed or participated in the demonstration, and 144 surveys were collected. The pilot ratings of the participants ranged from student to Air Transport Rating with an average of 1850 hours total flight time. The performance of the participants was surprisingly good, considering the minimal training in a completely new system concept. The overwhelming response was that technologies that simplify piloting tasks are enthusiastically welcomed by pilots of all experience levels. The increase in situation awareness and reduction in pilot workload were universally accepted and lauded as steps in the right direction.

AOPA Survey Summary of AGATE Concepts Demonstration, October 17-19, 1996. Volume 2; Original Survey Data

NASA Technical Reports Server (NTRS)

1997-01-01

An AGATE Concepts Demonstration was conducted at the Annual Aircraft Owners and Pilots Association (AOPA) Convention in 1996. The demonstration consisted of an interactive simulation of a single-pilot, single-engine aircraft in which the participant took off, flew a brief enroute segment and then flew a Global Positioning System (GPS) approach and landing. The participant was provided an advanced 'pathway-in-the-sky' presentation on both a head-up display and a head-down display to follow throughout the flight. A single lever power control and display concept was also provided for control of the engine throughout the flight A second head-down, multifunction display in the instrument panel provided a moving map display for navigation purposes and monitoring of the status of the aircraft's systems. An estimated 352 people observed or participated in the demonstration, and 144 surveys were collected. The pilot ratings of the participants ranged from student to Air Transport Rating with an average of 1850 hours total flight time. The performance of the participants was surprisingly good, considering the minimal training in a completely new system concept. The overwhelming response was that technologies that simplify piloting tasks are enthusiastically welcomed by pilots of all experience levels. The increase in situation awareness and reduction in pilot workload were universally accepted and lauded as steps in the right direction.

Isolation of anti-toxin single domain antibodies from a semi-synthetic spiny dogfish shark display library

PubMed Central

Liu, Jinny L; Anderson, George P; Goldman, Ellen R

2007-01-01

Background Shark heavy chain antibody, also called new antigen receptor (NAR), consists of one single Variable domain (VH), containing only two complementarity-determining regions (CDRs). The antigen binding affinity and specificity are mainly determined by these two CDRs. The good solubility, excellent thermal stability and complex sequence variation of small single domain antibodies (sdAbs) make them attractive alternatives to conventional antibodies. In this report, we construct and characterize a diversity enhanced semi-synthetic NAR V display library based on naturally occurring NAR V sequences. Results A semi-synthetic shark sdAb display library with a complexity close to 1e9 was constructed. This was achieved by introducing size and sequence variations in CDR3 using randomized CDR3 primers of three different lengths. Binders against three toxins, staphylococcal enterotoxin B (SEB), ricin, and botulinum toxin A (BoNT/A) complex toxoid, were isolated from panning the display library. Soluble sdAbs from selected binders were purified and evaluated using direct binding and thermal stability assays on the Luminex 100. In addition, sandwich assays using sdAb as the reporter element were developed to demonstrate their utility for future sensor applications. Conclusion We demonstrated the utility of a newly created hyper diversified shark NAR displayed library to serve as a source of thermal stable sdAbs against a variety of toxins. PMID:18021450

Quantum Point Contact Single-Nucleotide Conductance for DNA and RNA Sequence Identification.

PubMed

Afsari, Sepideh; Korshoj, Lee E; Abel, Gary R; Khan, Sajida; Chatterjee, Anushree; Nagpal, Prashant

2017-11-28

Several nanoscale electronic methods have been proposed for high-throughput single-molecule nucleic acid sequence identification. While many studies display a large ensemble of measurements as "electronic fingerprints" with some promise for distinguishing the DNA and RNA nucleobases (adenine, guanine, cytosine, thymine, and uracil), important metrics such as accuracy and confidence of base calling fall well below the current genomic methods. Issues such as unreliable metal-molecule junction formation, variation of nucleotide conformations, insufficient differences between the molecular orbitals responsible for single-nucleotide conduction, and lack of rigorous base calling algorithms lead to overlapping nanoelectronic measurements and poor nucleotide discrimination, especially at low coverage on single molecules. Here, we demonstrate a technique for reproducible conductance measurements on conformation-constrained single nucleotides and an advanced algorithmic approach for distinguishing the nucleobases. Our quantum point contact single-nucleotide conductance sequencing (QPICS) method uses combed and electrostatically bound single DNA and RNA nucleotides on a self-assembled monolayer of cysteamine molecules. We demonstrate that by varying the applied bias and pH conditions, molecular conductance can be switched ON and OFF, leading to reversible nucleotide perturbation for electronic recognition (NPER). We utilize NPER as a method to achieve >99.7% accuracy for DNA and RNA base calling at low molecular coverage (∼12×) using unbiased single measurements on DNA/RNA nucleotides, which represents a significant advance compared to existing sequencing methods. These results demonstrate the potential for utilizing simple surface modifications and existing biochemical moieties in individual nucleobases for a reliable, direct, single-molecule, nanoelectronic DNA and RNA nucleotide identification method for sequencing.

System Collects And Displays Demultiplexed Data

NASA Technical Reports Server (NTRS)

Reschke, Millard F.; Fariss, Julie L.; Kulecz, Walter B.; Paloski, William H.

1992-01-01

Electronic system collects, manipulates, and displays in real time results of manipulation of streams of data transmitted from remote scientific instrumentation. Interface circuit shifts data-and-clock signal from differential logic levels of multiplexer to single-ended logic levels of computer. System accommodates nonstandard data-transmission protocol. Software useful in applications where Macintosh computers used in real-time display and recording of data.

Metasecretome-selective phage display approach for mining the functional potential of a rumen microbial community.

PubMed

Ciric, Milica; Moon, Christina D; Leahy, Sinead C; Creevey, Christopher J; Altermann, Eric; Attwood, Graeme T; Rakonjac, Jasna; Gagic, Dragana

2014-05-12

In silico, secretome proteins can be predicted from completely sequenced genomes using various available algorithms that identify membrane-targeting sequences. For metasecretome (collection of surface, secreted and transmembrane proteins from environmental microbial communities) this approach is impractical, considering that the metasecretome open reading frames (ORFs) comprise only 10% to 30% of total metagenome, and are poorly represented in the dataset due to overall low coverage of metagenomic gene pool, even in large-scale projects. By combining secretome-selective phage display and next-generation sequencing, we focused the sequence analysis of complex rumen microbial community on the metasecretome component of the metagenome. This approach achieved high enrichment (29 fold) of secreted fibrolytic enzymes from the plant-adherent microbial community of the bovine rumen. In particular, we identified hundreds of heretofore rare modules belonging to cellulosomes, cell-surface complexes specialised for recognition and degradation of the plant fibre. As a method, metasecretome phage display combined with next-generation sequencing has a power to sample the diversity of low-abundance surface and secreted proteins that would otherwise require exceptionally large metagenomic sequencing projects. As a resource, metasecretome display library backed by the dataset obtained by next-generation sequencing is ready for i) affinity selection by standard phage display methodology and ii) easy purification of displayed proteins as part of the virion for individual functional analysis.

Frameshifting in the p6 cDNA phage display system.

PubMed

Govarts, Cindy; Somers, Klaartje; Stinissen, Piet; Somers, Veerle

2010-12-20

Phage display is a powerful technique that enables easy identification of targets for any type of ligand. Targets are displayed at the phage surface as a fusion protein to one of the phage coat proteins. By means of a repeated process of affinity selection on a ligand, specific enrichment of displayed targets will occur. In our studies using C-terminal display of cDNA fragments to phage coat protein p6, we noticed the occasional enrichment of targets that do not contain an open reading frame. This event has previously been described in other phage display studies using N-terminal display of targets to phage coat proteins and was due to uncommon translational events like frameshifting. The aim of this study was to examine if C-terminal display of targets to p6 is also subjected to frameshifting. To this end, an enriched target not containing an open reading frame was selected and an E-tag was coupled at the C-terminus in order to measure target display at the surface of the phage. The tagged construct was subsequently expressed in 3 different reading frames and display of both target and E-tag measured to detect the occurrence of frameshifting. As a result, we were able to demonstrate display of the target both in the 0 and in the +1 reading frame indicating that frameshifting can also take place when C-terminal fusion to minor coat protein p6 is applied.

Integrating critical interface elements for intuitive single-display aviation control of UAVs

NASA Astrophysics Data System (ADS)

Cooper, Joseph L.; Goodrich, Michael A.

2006-05-01

Although advancing levels of technology allow UAV operators to give increasingly complex commands with expanding temporal scope, it is unlikely that the need for immediate situation awareness and local, short-term flight adjustment will ever be completely superseded. Local awareness and control are particularly important when the operator uses the UAV to perform a search or inspection task. There are many different tasks which would be facilitated by search and inspection capabilities of a camera-equipped UAV. These tasks range from bridge inspection and news reporting to wilderness search and rescue. The system should be simple, inexpensive, and intuitive for non-pilots. An appropriately designed interface should (a) provide a context for interpreting video and (b) support UAV tasking and control, all within a single display screen. In this paper, we present and analyze an interface that attempts to accomplish this goal. The interface utilizes a georeferenced terrain map rendered from publicly available altitude data and terrain imagery to create a context in which the location of the UAV and the source of the video are communicated to the operator. Rotated and transformed imagery from the UAV provides a stable frame of reference for the operator and integrates cleanly into the terrain model. Simple icons overlaid onto the main display provide intuitive control and feedback when necessary but fade to a semi-transparent state when not in use to avoid distracting the operator's attention from the video signal. With various interface elements integrated into a single display, the interface runs nicely on a small, portable, inexpensive system with a single display screen and simple input device, but is powerful enough to allow a single operator to deploy, control, and recover a small UAV when coupled with appropriate autonomy. As we present elements of the interface design, we will identify concepts that can be leveraged into a large class of UAV applications.

Evaluation of Head-Worn Display Concepts for Commercial Aircraft Taxi Operations

NASA Technical Reports Server (NTRS)

Bailey, Randall E.; Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Kramer, Lynda J.

2007-01-01

Previous research has demonstrated that a Head-Up Display (HUD) can be used to enable more capacity and safer aircraft surface operations. This previous research also noted that the HUD exhibited two major limitations which hindered the full potential of the display concept: 1) the monochrome HUD format; and, 2) a limited, fixed field of regard. Full-color Head Worn Displays (HWDs) with very small sizes and weights are emerging to the extent that this technology may be practical for commercial and business aircraft operations. By coupling the HWD with a head tracker, full-color, out-the-window display concepts with an unlimited field-of-regard may be realized to improve efficiency and safety in surface operations. A ground simulation experiment was conducted at NASA Langley to evaluate the efficacy of head-worn display applications which may directly address the limitations of the HUD while retaining all of its advantages in surface operations. The simulation experiment used airline crews to evaluate various displays (HUD, HWD) and display concepts in an operationally realistic environment by using a Chicago, O Hare airport database. The results pertaining to the implications of HWDs for commercial business and transport aviation applications are presented herein. Overall HWD system latency was measured and found to be acceptable, but not necessarily optimal. A few occurrences of simulator sickness were noted while wearing the HWD, but overall there appears to be commercial pilot acceptability and usability to the concept. Many issues were identified which need to be addressed in future research including continued reduction in user encumbrance due to the HWD, and improvement in image alignment, accuracy, and boresighting.

[Surface display of phytase on Saccharomyces cerevisiae for efficient bioethanol production from corn starch].

PubMed

Xiao, Yan; Chen, Xianzhong; Shen, Wei; Yang, Haiquan; Fan, You

2015-12-01

Production of bioethanol using starch as raw material has become a very prominent technology. However, phytate in the raw material not only decreases ethanol production efficiency, but also increases phosphorus discharge. In this study, to decrease phytate content in an ethanol fermentationprocess, Saccharomyces cerevisiae was engineered forheterologous expression of phytase on the cell surface. The phy gene encoding phytase gene was fused with the C-terminal-half region of α-agglutinin and then inserted downstream of the secretion signal gene, to produce a yeast surface-display expression vector pMGK-AG-phy, which was then transformed into S. cerevisiae. The recombinant yeast strain, PHY, successfully displayed phytase on the surface of cells producing 6.4 U/g wet cells and its properties were further characterized. The growthrate and ethanol production of the PHY strain were faster than the parent S. cerevisiae strain in the fermentation medium by simultaneous saccharification and fermentation. Moreover, the phytate concentration decreased by 91% in dry vinasse compared to the control. In summary, we constructed recombinant S. cerevisiae strain displaying phytase on the cell surface, which could effectively reduce the content of phytate, improve the utilization value of vinasse and reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate.

Bioinspired, roughness-induced, water and oil super-philic and super-phobic coatings prepared by adaptable layer-by-layer technique

PubMed Central

Brown, Philip S.; Bhushan, Bharat

2015-01-01

Coatings with specific surface wetting properties are of interest for anti-fouling, anti-fogging, anti-icing, self-cleaning, anti-smudge, and oil-water separation applications. Many previous bioinspired surfaces are of limited use due to a lack of mechanical durability. Here, a layer-by-layer technique is utilized to create coatings with four combinations of water and oil repellency and affinity. An adapted layer-by-layer approach is tailored to yield specific surface properties, resulting in a durable, functional coating. This technique provides necessary flexibility to improve substrate adhesion combined with desirable surface chemistry. Polyelectrolyte binder, SiO2 nanoparticles, and silane or fluorosurfactant layers are deposited, combining surface roughness and necessary chemistry to result in four different coatings: superhydrophilic/superoleophilic, superhydrophobic/superoleophilic, superhydrophobic/superoleophobic, and superhydrophilic/superoleophobic. The superoleophobic coatings display hexadecane contact angles >150° with tilt angles <5°, whilst the superhydrophobic coatings display water contact angles >160° with tilt angles <2°. One coating combines both oleophobic and hydrophobic properties, whilst others mix and match oil and water repellency and affinity. Coating durability was examined through the use of micro/macrowear experiments. These coatings display transparency acceptable for some applications. Fabrication via this novel combination of techniques results in durable, functional coatings displaying improved performance compared to existing work where either durability or functionality is compromised. PMID:26353971

Yeast Surface Display of Two Proteins Previously Shown to Be Protective Against White Spot Syndrome Virus (WSSV) in Shrimp.

PubMed

Ananphongmanee, Vorawit; Srisala, Jiraporn; Sritunyalucksana, Kallaya; Boonchird, Chuenchit

2015-01-01

Cell surface display using the yeasts Saccharomyces cerevisiae and Pichia pastoris has been extensively developed for application in bioindustrial processes. Due to the rigid structure of their cell walls, a number of proteins have been successfully displayed on their cell surfaces. It was previously reported that the viral binding protein Rab7 from the giant tiger shrimp Penaeus monodon (PmRab7) and its binding partner envelope protein VP28 of white spot syndrome virus (WSSV) could independently protect shrimp against WSSV infection. Thus, we aimed to display these two proteins independently on the cell surfaces of 2 yeast clones with the ultimate goal of using a mixture of the two clones as an orally deliverable, antiviral agent to protect shrimp against WSSV infection. PmRab7 and VP28 were modified by N-terminal tagging to the C-terminal half of S. cerevisiae α-agglutinin. DNA fragments, harboring fused-gene expression cassettes under control of an alcohol oxidase I (AOX1) promoter were constructed and used to transform the yeast cells. Immunofluorescence microscopy with antibodies specific to both proteins demonstrated that mutated PmRab7 (mPmRab7) and partial VP28 (pVP28) were localized on the cell surfaces of the respective clones, and fluorescence intensity for each was significantly higher than that of control cells by flow cytometry. Enzyme-linked immunosorbant assay (ELISA) using cells displaying mPmRab7 or pVP28 revealed that the binding of specific antibodies for each was dose-dependent, and could be saturated. In addition, the binding of mPmRab7-expressing cells with free VP28, and vice versa was dose dependent. Binding between the two surface-expressed proteins was confirmed by an assay showing agglutination between cells expressing complementary mPmRab7 and pVP28. In summary, our genetically engineered P. pastoris can display biologically active mPmRab7 and pVP28 and is now ready for evaluation of efficacy in protecting shrimp against WSSV by oral administration.

Program For A Pushbutton Display

NASA Technical Reports Server (NTRS)

Busquets, Anthony M.; Luck, William S., Jr.

1989-01-01

Programmable Display Pushbutton (PDP) is pushbutton device available from Micro Switch having programmable 16X35 matrix of light-emitting diodes on pushbutton surface. Any desired legends display on PDP's, producing user-friendly applications reducing need for dedicated manual controls. Interacts with operator, calls for correct response before transmitting next message. Both simple manual control and sophisticated programmable link between operator and host system. Programmable Display Pushbutton Legend Editor (PDPE) computer program used to create light-emitting-diode (LED) displays for pushbuttons. Written in FORTRAN.

Thermomechanical Characterization of SiC Fiber Tows and Implications for CMC

NASA Technical Reports Server (NTRS)

Yun, H. M.; DiCarlo, J. A.

1999-01-01

In order to better understand SiC fiber behavior within CMC microstructures, mechanical tests were performed on multifilament tows consisting of different types of as produced and pretreated fibers. Tensile strengths of tows and single fibers were measured at room temperature for nonstoichiometric Hi-Nicalon and ZMI fibers and for stoichiometric Hi-Nicalon-S, Tyranno SA. and Sylramic fibers. Based on simple bundle theory, measured strengths for as-produced and sized tows were in general agreement with the single fiber results. However, after sizing removal under inert conditions, tow strengths for the coarser grained stoichiometric fibers were typically lower than those predicted from individual fiber data. This effect is attributed to enhanced fiber-fiber mechanical interaction caused by sizing removal from the rough surfaces of these fibers. In support of this, tow strengths remained high for those fiber types with fine grains or excess surface carbon; and, when re-coated with a BN interphase coating, tow strengths for the coarser grained fibers returned to their as-produced values. When the tows were pretreated in air at intermediate temperatures, tow strengths decreased in a manner that could be correlated with the oxidation characteristics of each fiber type as measured by thermogravimetric analysis. The creep and rupture properties of Hi-Nicalon and Sylramic tows were also measured in air and argon from 1200 to 1400 C. Although displaying transient and environmental effects similar to single fibers, the tows crept faster at short times and slower at long times. This resulted in the tow rupture strengths at long time being much greater than the rupture strengths of single fibers. The CMC implications of the tow results are discussed, as well as the benefits and limitations of tow testing.

Computer-composite mapping for geologists

USGS Publications Warehouse

van Driel, J.N.

1980-01-01

A computer program for overlaying maps has been tested and evaluated as a means for producing geologic derivative maps. Four maps of the Sugar House Quadrangle, Utah, were combined, using the Multi-Scale Data Analysis and Mapping Program, in a single composite map that shows the relative stability of the land surface during earthquakes. Computer-composite mapping can provide geologists with a powerful analytical tool and a flexible graphic display technique. Digitized map units can be shown singly, grouped with different units from the same map, or combined with units from other source maps to produce composite maps. The mapping program permits the user to assign various values to the map units and to specify symbology for the final map. Because of its flexible storage, easy manipulation, and capabilities of graphic output, the composite-mapping technique can readily be applied to mapping projects in sedimentary and crystalline terranes, as well as to maps showing mineral resource potential. ?? 1980 Springer-Verlag New York Inc.

Amplicon Sequencing of the slpH Locus Permits Culture-Independent Strain Typing of Lactobacillus helveticus in Dairy Products

PubMed Central

Moser, Aline; Wüthrich, Daniel; Bruggmann, Rémy; Eugster-Meier, Elisabeth; Meile, Leo; Irmler, Stefan

2017-01-01

The advent of massive parallel sequencing technologies has opened up possibilities for the study of the bacterial diversity of ecosystems without the need for enrichment or single strain isolation. By exploiting 78 genome data-sets from Lactobacillus helveticus strains, we found that the slpH locus that encodes a putative surface layer protein displays sufficient genetic heterogeneity to be a suitable target for strain typing. Based on high-throughput slpH gene sequencing and the detection of single-base DNA sequence variations, we established a culture-independent method to assess the biodiversity of the L. helveticus strains present in fermented dairy food. When we applied the method to study the L. helveticus strain composition in 15 natural whey cultures (NWCs) that were collected at different Gruyère, a protected designation of origin (PDO) production facilities, we detected a total of 10 sequence types (STs). In addition, we monitored the development of a three-strain mix in raclette cheese for 17 weeks. PMID:28775722

Prediction of another semimetallic silicene allotrope with Dirac fermions

NASA Astrophysics Data System (ADS)

Wu, Haiping; Qian, Yan; Du, Zhengwei; Zhu, Renzhu; Kan, Erjun; Deng, Kaiming

2017-11-01

Materials with Dirac point are so amazing since the charge carriers are massless and have an effective speed of light. However, among the predicted two-dimensional silicon allotropes with Dirac point, no one has been directly proved by experiment. This fact motivates us to search for other two-dimensional silicon allotropes. As a result, another stable single atomic layer thin silicon allotrope is found with the help of CALYPSO code in this work. This silicene allotrope is composed of eight-membered rings linked by Si-Si bonds with buckling formation. The electronic calculation reveals that it behaves as a nodal line semimetal with the linear energy dispersion relation near the Fermi surface. Notably, the ab initio molecular dynamics simulations display that the original atomic configuration can be remained even at an extremely high temperature of 1000 K. Additionally, hydrogenation could induce a semimetal-semiconductor transition in this silicene allotrope. We hope this work can expand the family of single atomic layer thin silicon allotropes with special applications.

Architectural transitions in Vibrio cholerae biofilms at single-cell resolution

PubMed Central

Drescher, Knut; Dunkel, Jörn; Nadell, Carey D.; van Teeffelen, Sven; Grnja, Ivan; Wingreen, Ned S.; Stone, Howard A.; Bassler, Bonnie L.

2016-01-01

Many bacterial species colonize surfaces and form dense 3D structures, known as biofilms, which are highly tolerant to antibiotics and constitute one of the major forms of bacterial biomass on Earth. Bacterial biofilms display remarkable changes during their development from initial attachment to maturity, yet the cellular architecture that gives rise to collective biofilm morphology during growth is largely unknown. Here, we use high-resolution optical microscopy to image all individual cells in Vibrio cholerae biofilms at different stages of development, including colonies that range in size from 2 to 4,500 cells. From these data, we extracted the precise 3D cellular arrangements, cell shapes, sizes, and global morphological features during biofilm growth on submerged glass substrates under flow. We discovered several critical transitions of the internal and external biofilm architectures that separate the major phases of V. cholerae biofilm growth. Optical imaging of biofilms with single-cell resolution provides a new window into biofilm formation that will prove invaluable to understanding the mechanics underlying biofilm development. PMID:26933214

Realization of Multi-Stable Ground States in a Nematic Liquid Crystal by Surface and Electric Field Modification

NASA Astrophysics Data System (ADS)

Gwag, Jin Seog; Kim, Young-Ki; Lee, Chang Hoon; Kim, Jae-Hoon

2015-06-01

Owing to the significant price drop of liquid crystal displays (LCDs) and the efforts to save natural resources, LCDs are even replacing paper to display static images such as price tags and advertising boards. Because of a growing market demand on such devices, the LCD that can be of numerous surface alignments of directors as its ground state, the so-called multi-stable LCD, comes into the limelight due to the great potential for low power consumption. However, the multi-stable LCD with industrial feasibility has not yet been successfully performed. In this paper, we propose a simple and novel configuration for the multi-stable LCD. We demonstrate experimentally and theoretically that a battery of stable surface alignments can be achieved by the field-induced surface dragging effect on an aligning layer with a weak surface anchoring. The simplicity and stability of the proposed system suggest that it is suitable for the multi-stable LCDs to display static images with low power consumption and thus opens applications in various fields.

Proof-of-concept switchable hydrophobic/hydrophilic patterned surfaces from thermo-mechanically tailored acrylate systems

NASA Astrophysics Data System (ADS)

Laursen, Christopher M.

A novel, proof-of-concept, switchable hydrophobic/hydrophilic structured surface targeted to assist in antifouling of materials in aqueous environments was created through the development of a multi-tiered platform. The understructure consists of a thermo-mechanically tailored acrylate based polymer patterned in a pillared array, which was then overlaid with spatially tailored hydrophobic/hydrophilic surface chemistry treatments. Development focused on the synthesis of a ternary acrylate system displaying proper thermo-mechanical behavior in submerged conditions for the understructure, creation of a sufficient soft molding technique, and methods to chemically alter water-surface wetting interactions. The final acrylate based polymer constituents were chosen based on expected low-toxicity and the ability to be photopolymerized, while the final system displayed appropriate mechanical toughness, water absorption, and material stiffness over a select temperature window. This was important as alteration in wettability characteristics relied upon a stark transition in the polymeric materials stiffness within a narrow temperature range. The material qualitatively displayed a more hydrophobic state with the pillared surface structures erect, and a more hydrophilic state with the pillars bent over.

Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes.

PubMed

Xiong, Guang; Elam, Jeffrey W; Feng, Hao; Han, Catherine Y; Wang, Hsien-Hau; Iton, Lennox E; Curtiss, Larry A; Pellin, Michael J; Kung, Mayfair; Kung, Harold; Stair, Peter C

2005-07-28

Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.

The possible equilibrium shapes of static pendant drops

NASA Astrophysics Data System (ADS)

Sumesh, P. T.; Govindarajan, Rama

2010-10-01

Analytical and numerical studies are carried out on the shapes of two-dimensional and axisymmetric pendant drops hanging under gravity from a solid surface. Drop shapes with both pinned and equilibrium contact angles are obtained naturally from a single boundary condition in the analytical energy optimization procedure. The numerical procedure also yields optimum energy shapes, satisfying Young's equation without the explicit imposition of a boundary condition at the plate. It is shown analytically that a static pendant two-dimensional drop can never be longer than 3.42 times the capillary length. A related finding is that a range of existing solutions for long two-dimensional drops correspond to unphysical drop shapes. Therefore, two-dimensional drops of small volume display only one static solution. In contrast, it is known that axisymmetric drops can display multiple solutions for a given volume. We demonstrate numerically that there is no limit to the height of multiple-lobed Kelvin drops, but the total volume is finite, with the volume of successive lobes forming a convergent series. The stability of such drops is in question, though. Drops of small volume can attain large heights. A bifurcation is found within the one-parameter space of Laplacian shapes, with a range of longer drops displaying a minimum in energy in the investigated space. Axisymmetric Kelvin drops exhibit an infinite number of bifurcations.

Health monitoring display system for a complex plant

DOEpatents

Ridolfo, Charles F [Bloomfield, CT; Harmon, Daryl L [Enfield, CT; Colin, Dreyfuss [Enfield, CT

2006-08-08

A single page enterprise wide level display provides a comprehensive readily understood representation of the overall health status of a complex plant. Color coded failure domains allow rapid intuitive recognition of component failure status. A three-tier hierarchy of displays provide details on the health status of the components and systems displayed on the enterprise wide level display in a manner that supports a logical drill down to the health status of sub-components on Tier 1 to expected faults of the sub-components on Tier 2 to specific information relative to expected sub-component failures on Tier 3.

Double-heterojunction nanorod light-responsive LEDs for display applications.

PubMed

Oh, Nuri; Kim, Bong Hoon; Cho, Seong-Yong; Nam, Sooji; Rogers, Steven P; Jiang, Yiran; Flanagan, Joseph C; Zhai, You; Kim, Jae-Hwan; Lee, Jungyup; Yu, Yongjoon; Cho, Youn Kyoung; Hur, Gyum; Zhang, Jieqian; Trefonas, Peter; Rogers, John A; Shim, Moonsub

2017-02-10

Dual-functioning displays, which can simultaneously transmit and receive information and energy through visible light, would enable enhanced user interfaces and device-to-device interactivity. We demonstrate that double heterojunctions designed into colloidal semiconductor nanorods allow both efficient photocurrent generation through a photovoltaic response and electroluminescence within a single device. These dual-functioning, all-solution-processed double-heterojunction nanorod light-responsive light-emitting diodes open feasible routes to a variety of advanced applications, from touchless interactive screens to energy harvesting and scavenging displays and massively parallel display-to-display data communication. Copyright © 2017, American Association for the Advancement of Science.

A multiresolution halftoning algorithm for progressive display

NASA Astrophysics Data System (ADS)

Mukherjee, Mithun; Sharma, Gaurav

2005-01-01

We describe and implement an algorithmic framework for memory efficient, 'on-the-fly' halftoning in a progressive transmission environment. Instead of a conventional approach which repeatedly recalls the continuous tone image from memory and subsequently halftones it for display, the proposed method achieves significant memory efficiency by storing only the halftoned image and updating it in response to additional information received through progressive transmission. Thus the method requires only a single frame-buffer of bits for storage of the displayed binary image and no additional storage is required for the contone data. The additional image data received through progressive transmission is accommodated through in-place updates of the buffer. The method is thus particularly advantageous for high resolution bi-level displays where it can result in significant savings in memory. The proposed framework is implemented using a suitable multi-resolution, multi-level modification of error diffusion that is motivated by the presence of a single binary frame-buffer. Aggregates of individual display bits constitute the multiple output levels at a given resolution. This creates a natural progression of increasing resolution with decreasing bit-depth.

The effects of display and autopilot functions on pilot workload for Single Pilot Instrument Flight Rule (SPIFR) operations

NASA Technical Reports Server (NTRS)

Hoh, Roger H.; Smith, James C.; Hinton, David A.

1987-01-01

An analytical and experimental research program was conducted to develop criteria for pilot interaction with advanced controls and displays in single pilot instrument flight rules (SPIFR) operations. The analytic phase reviewed fundamental considerations for pilot workload taking into account existing data, and using that data to develop a divided attention SPIFR pilot workload model. The pilot model was utilized to interpret the two experimental phases. The first experimental phase was a flight test program that evaluated pilot workload in the presence of current and near-term displays and autopilot functions. The second experiment was conducted on a King Air simulator, investigating the effects of co-pilot functions in the presence of very high SPIFR workload. The results indicate that the simplest displays tested were marginal for SPIFR operations. A moving map display aided the most in mental orientation, but had inherent deficiencies as a stand alone replacement for an HSI. Autopilot functions were highly effective for reducing pilot workload. The simulator tests showed that extremely high workload situations can be adequately handled when co-pilot functions are provided.

An anti-CD30 single-chain Fv selected by phage display and fused to Pseudomonas exotoxin A (Ki-4(scFv)-ETÁ) is a potent immunotoxin against a Hodgkin-derived cell line

PubMed Central

Klimka, A; Barth, S; Matthey, B; Roovers, R C; Lemke, H; Hansen, H; Arends, J-W; Diehl, V; Hoogenboom, H R; Engert, A

1999-01-01

The human CD30 receptor is highly overexpressed on the surface of Hodgkin Reed-Sternberg cells and has been shown to be an excellent target for selective immunotherapy using monoclonal antibody-based agents such as immunotoxins. To construct a new recombinant immunotoxin for possible clinical use in patients with Hodgkin's lymphoma, we have chosen the murine anti-CD30 hybridoma Ki-4 to generate a high-affinity Ki-4 single-chain variable fragment (scFv). Hybridoma V-genes were polymerase chain reaction-amplified, assembled, cloned and expressed as a mini-library for display on filamentous phage. Functional Ki-4 scFv were obtained by selection of binding phage on the Hodgkin lymphoma-derived, CD30-expressing cell line L540Cy. The selected recombinant Ki-4 scFv was shown to specifically bind to an overlapping epitope on the CD30 antigen with binding kinetics similar to those of the original antibody. The Ki-4 scFv was subsequently fused to a deletion mutant of Pseudomonas exotoxin A (ETÁ). The resulting immunotoxin Ki-4(scFv)-ETÁ specifically binds to CD30+ L540Cy cells and inhibits the protein synthesis by 50% at a concentration (IC50) of 43 pM. This recombinant immunotoxin is a promising candidate for further clinical evaluation in patients with Hodgkin's lymphoma or other CD30+ malignancies. © 1999 Cancer Research Campaign PMID:10376974

Extension of the carotenoid test to superficially porous C18 bonded phases, aromatic ligand types and new classical C18 bonded phases.

PubMed

Lesellier, E

2012-11-30

The recent introduction of new stationary phases for liquid chromatography based on superficially porous particles, called core-shell or fused-core, dramatically improved the separation performances through very high efficiency, due mainly to reduced eddy diffusion. However, few studies have evaluated the retention and selectivity of C18 phases based on such particles, despite some retention order change reported in literature between some of these phases. The carotenoid test has been developed a few years ago in the goal to compare the chromatographic properties of C18 bonded phases. Based on the analysis of carotenoid pigments by using Supercritical Fluid Chromatography (SFC), it allows, with a single analysis, to measure three main properties of reversed phase chromatography stationary phases: hydrophobicity, polar surface activity and shape selectivity. Previous studies showed the effect of the endcapping treatment, the bonding density, the pore size, and the type of bonding (monomeric vs. polymeric) on these studied properties, and described the classification map used for a direct column comparison. It was applied to ten ODS superficially porous stationary phases, showing varied chromatographic behaviors amongst these phases. As expected, due to the lower specific surface area, these superficially porous phases are less hydrophobic than the fully porous one. In regards of the polar surface activity (residual silanols) and to the shape selectivity, some of these superficially porous phases display close chromatographic properties (Poroshell 120, Halo C18, Ascentis Express, Accucore C18, Nucleoshell C18 on one side and Aeris Wide pore, Aeris peptide and Kinetex XDB on the other side), whereas others, Kinetex C18 and Halo peptide ES C18 display more specific ones. Besides, they can be compared to classical fully porous phases, in the goal to improve method transfer from fully to superficially porous particles. By the way, the paper also report the extension of the test to other ligands such as naphtyl, cholester, phenyl-hexyl, or to the new ODS bonded phases, such as charge surface hybrid phases, High Strength Silica, and Hybrid ones, and also presents results for identical brands using different particle size, such as Luna and Synergi phases. Phenyl-hexyl and napthyl ligands show rather close properties, low hydrophobicity, high polar surface activity and specific shape selectivity, whereas, at the opposite, the cholester phase display a polymeric behavior and a high hydrophobicity. Finally, additional classical (fully porous particles) C18 bonded phases are also reported to complete the data set presented in previous papers. Copyright © 2012 Elsevier B.V. All rights reserved.

Simple liquid crystal display backlight unit comprising only a single-sheet micropatterned polydimethylsiloxane (PDMS) light-guide plate.

PubMed

Lee, Joo-Hyung; Lee, Hong-Seok; Lee, Byung-Kee; Choi, Won-Seok; Choi, Hwan-Young; Yoon, Jun-Bo

2007-09-15

A simple liquid crystal display (LCD) backlight unit (BLU) comprising only a single-sheet polydimethylsiloxane (PDMS) light-guide plate (LGP) has been developed. The PDMS LGP, having micropatterns with an inverse-trapezoidal cross section, was fabricated by backside 3-D diffuser lithography followed by PDMS-to-PDMS replication. The fabricated BLU showed an average luminance of 2878 cd/m(2) with 73.3% uniformity when mounted in a 5.08 cm backlight module with four side view 0.85cd LEDs. The developed BLU can greatly reduce the cost and thickness of LCDs, and it can be applied to flexible displays as a flexible light source due to the flexible characteristic of the PDMS itself.

Planar electroluminescent panel techniques

NASA Technical Reports Server (NTRS)

Kerr, C.; Kell, R. E.

1973-01-01

Investigations of planar electroluminescent multipurpose displays with latch-in memory are described. An 18 x 24 in. flat, thin address panel with elements spacing of 0.100 in. was constructed which demonstrated essentially uniform luminosity of 3-5 foot lamberts for each of its 43200 EL cells. A working model of a 4-bit EL-PC (electroluminescent photoconductive) electrooptical decoder was made which demonstrated the feasibility of this concept. A single-diagram electroluminescent display device with photoconductive-electroluminescent latch-in memory was constructed which demonstrated the conceptual soundness of this principle. Attempts to combine these principles in a single PEL multipurpose display with latch-in memory were unsuccessful and were judged to exceed the state-of-the-art for close-packed (0.10 in. centers) photoconductor-electroluminescent cell assembly.

Enhanced cell-surface display of a heterologous protein using SED1 anchoring system in SED1-disrupted Saccharomyces cerevisiae strain.

PubMed

Bamba, Takahiro; Inokuma, Kentaro; Hasunuma, Tomohisa; Kondo, Akihiko

2018-03-01

Yeast displaying enzymes on the cell surface are used for developing whole-cell biocatalysts. High enzyme activity on the cell surface is required in certain applications such as direct ethanol production from lignocellulosic materials. However, the cell surface enzyme activity is limited by several factors, one of which is the protein amount of the yeast cell wall. In this study, we attempted to improve the incorporation capacity of a displayed heterologous enzyme by disrupting a native cell-wall protein. β-Glucosidase (BGL1) from Aspergillus aculeatus was fused with Saccharomyces cerevisiae Sed1 and displayed on the cell surface of S. cerevisiae BY4741 strain and its SED1 disruptant. Sed1 is one of the most abundant stationary phase yeast cell wall protein. A time course analysis revealed that BGL1 activity of the control strain reached saturation after 48 h of cultivation. In contrast, the BGL1 activity of the SED1 disruptant increased until 72 h of cultivation and was 22% higher than that of the control strain. We also performed relative quantification of cell wall proteins of these strains by nanoscale ultra pressure liquid chromatography electrospray ionization quadrupole time-of-flight tandem mass spectrometry (nano-UPLC-MS E ). The amount of the cell wall-associated BGL1 per unit dry cell-weight of the SED1 disruptant was 19% higher than that of the control strain. These results suggested that the incorporation capacity of the cell wall for BGL1 was increased by disruption of SED1. Disruption of SED1 would be a promising approach for improving display efficiency of heterologous protein fused with Sed1. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Solution growth of single crystal methylammonium lead halide perovskite nanostructures for optoelectronic and photovoltaic applications.

PubMed

Fu, Yongping; Meng, Fei; Rowley, Matthew B; Thompson, Blaise J; Shearer, Melinda J; Ma, Dewei; Hamers, Robert J; Wright, John C; Jin, Song

2015-05-06

Understanding crystal growth and improving material quality is important for improving semiconductors for electronic, optoelectronic, and photovoltaic applications. Amidst the surging interest in solar cells based on hybrid organic-inorganic lead halide perovskites and the exciting progress in device performance, improved understanding and better control of the crystal growth of these perovskites could further boost their optoelectronic and photovoltaic performance. Here, we report new insights on the crystal growth of the perovskite materials, especially crystalline nanostructures. Specifically, single crystal nanowires, nanorods, and nanoplates of methylammonium lead halide perovskites (CH3NH3PbI3 and CH3NH3PbBr3) are successfully grown via a dissolution-recrystallization pathway in a solution synthesis from lead iodide (or lead acetate) films coated on substrates. These single crystal nanostructures display strong room-temperature photoluminescence and long carrier lifetime. We also report that a solid-liquid interfacial conversion reaction can create a highly crystalline, nanostructured MAPbI3 film with micrometer grain size and high surface coverage that enables photovoltaic devices with a power conversion efficiency of 10.6%. These results suggest that single-crystal perovskite nanostructures provide improved photophysical properties that are important for fundamental studies and future applications in nanoscale optoelectronic and photonic devices.

Emotional display rules and emotional labor: the moderating role of commitment.

PubMed

Gosserand, Robin H; Diefendorff, James M

2005-11-01

The authors examined whether commitment to emotional display rules is a necessary condition for emotional display rules to affect behavior at work. Results using structural equation modeling revealed that display rule commitment moderated the relationships of emotional display rule perceptions with surface acting, deep acting, and positive affective delivery at work, such that the relationships were strong and positive when commitment to display rules was high and weak when commitment to display rules was low. These findings suggest that motivation plays a role in the emotional labor process in that individuals must be committed to display rules for these rules to affect behavior. ((c) 2005 APA, all rights reserved).

Undifferentiated Facial Electromyography Responses to Dynamic, Audio-Visual Emotion Displays in Individuals with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Rozga, Agata; King, Tricia Z.; Vuduc, Richard W.; Robins, Diana L.

2013-01-01

We examined facial electromyography (fEMG) activity to dynamic, audio-visual emotional displays in individuals with autism spectrum disorders (ASD) and typically developing (TD) individuals. Participants viewed clips of happy, angry, and fearful displays that contained both facial expression and affective prosody while surface electrodes measured…

A Dark Horse Medium in Basic Business

ERIC Educational Resources Information Center

Eckert, Sidney W.

1974-01-01

The Dark Horse (DH) board is described and discussed as one medium which may be utilized in the classroom. The DH Board holds fairly heavy three-dimensional display objects and consists of two components: a special material which serves as the display surface and an adhesive material which is fixed to objects displayed. (SC)

Patch Finder Plus (PFplus): a web server for extracting and displaying positive electrostatic patches on protein surfaces.

PubMed

Shazman, Shula; Celniker, Gershon; Haber, Omer; Glaser, Fabian; Mandel-Gutfreund, Yael

2007-07-01

Positively charged electrostatic patches on protein surfaces are usually indicative of nucleic acid binding interfaces. Interestingly, many proteins which are not involved in nucleic acid binding possess large positive patches on their surface as well. In some cases, the positive patches on the protein are related to other functional properties of the protein family. PatchFinderPlus (PFplus) http://pfp.technion.ac.il is a web-based tool for extracting and displaying continuous electrostatic positive patches on protein surfaces. The input required for PFplus is either a four letter PDB code or a protein coordinate file in PDB format, provided by the user. PFplus computes the continuum electrostatics potential and extracts the largest positive patch for each protein chain in the PDB file. The server provides an output file in PDB format including a list of the patch residues. In addition, the largest positive patch is displayed on the server by a graphical viewer (Jmol), using a simple color coding.

Recent advances in yeast cell-surface display technologies for waste biorefineries.

PubMed

Liu, Zhuo; Ho, Shih-Hsin; Hasunuma, Tomohisa; Chang, Jo-Shu; Ren, Nan-Qi; Kondo, Akihiko

2016-09-01

Waste biorefinery aims to maximize the output of value-added products from various artificial/agricultural wastes by using integrated bioprocesses. To make waste biorefinery economically feasible, it is thus necessary to develop a low-cost, environment-friendly technique to perform simultaneous biodegradation and bioconversion of waste materials. Cell-surface display engineering is a novel, cost-effective technique that can auto-immobilize proteins on the cell exterior of microorganisms, and has been applied for use with waste biofinery. Through tethering different enzymes (e.g., cellulase, lipase, and protease) or metal-binding peptides on cell surfaces, various yeast strains can effectively produce biofuels and biochemicals from sugar/protein-rich waste materials, catalyze waste oils into biodiesels, or retrieve heavy metals from wastewater. This review critically summarizes recent applications of yeast cell-surface display on various types of waste biorefineries, highlighting its potential and future challenges with regard to commercializing this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Patch Finder Plus (PFplus): A web server for extracting and displaying positive electrostatic patches on protein surfaces

PubMed Central

Shazman, Shula; Celniker, Gershon; Haber, Omer; Glaser, Fabian; Mandel-Gutfreund, Yael

2007-01-01

Positively charged electrostatic patches on protein surfaces are usually indicative of nucleic acid binding interfaces. Interestingly, many proteins which are not involved in nucleic acid binding possess large positive patches on their surface as well. In some cases, the positive patches on the protein are related to other functional properties of the protein family. PatchFinderPlus (PFplus) http://pfp.technion.ac.il is a web-based tool for extracting and displaying continuous electrostatic positive patches on protein surfaces. The input required for PFplus is either a four letter PDB code or a protein coordinate file in PDB format, provided by the user. PFplus computes the continuum electrostatics potential and extracts the largest positive patch for each protein chain in the PDB file. The server provides an output file in PDB format including a list of the patch residues. In addition, the largest positive patch is displayed on the server by a graphical viewer (Jmol), using a simple color coding. PMID:17537808

Development and Evaluation of Single Domain Antibodies for Vaccinia and the L1 Antigen

PubMed Central

Walper, Scott A.; Liu, Jinny L.; Zabetakis, Daniel; Anderson, George P.; Goldman, Ellen R.

2014-01-01

There is ongoing interest to develop high affinity, thermal stable recognition elements to replace conventional antibodies in biothreat detection assays. As part of this effort, single domain antibodies that target vaccinia virus were developed. Two llamas were immunized with killed viral particles followed by boosts with the recombinant membrane protein, L1, to stimulate the immune response for envelope and membrane proteins of the virus. The variable domains of the induced heavy chain antibodies were selected from M13 phage display libraries developed from isolated RNA. Selection via biopanning on the L1 antigen produced single domain antibodies that were specific and had affinities ranging from 4×10−9 M to 7.0×10−10 M, as determined by surface plasmon resonance. Several showed good ability to refold after heat denaturation. These L1-binding single domain antibodies, however, failed to recognize the killed vaccinia antigen. Useful vaccinia binding single domain antibodies were isolated by a second selection using the killed virus as the target. The virus binding single domain antibodies were incorporated in sandwich assays as both capture and tracer using the MAGPIX system yielding limits of detection down to 4×105 pfu/ml, a four-fold improvement over the limit obtained using conventional antibodies. This work demonstrates the development of anti-vaccinia single domain antibodies and their incorporation into sandwich assays for viral detection. It also highlights the properties of high affinity and thermal stability that are hallmarks of single domain antibodies. PMID:25211488

Effects of in-vehicle warning information displays with or without spatial compatibility on driving behaviors and response performance.

PubMed

Liu, Yung-Ching; Jhuang, Jing-Wun

2012-07-01

A driving simulator study was conducted to evaluate the effects of five in-vehicle warning information displays upon drivers' emergent response and decision performance. These displays include visual display, auditory displays with and without spatial compatibility, hybrid displays in both visual and auditory format with and without spatial compatibility. Thirty volunteer drivers were recruited to perform various tasks that involved driving, stimulus-response, divided attention and stress rating. Results show that for displays of single-modality, drivers benefited more when coping with visual display of warning information than auditory display with or without spatial compatibility. However, auditory display with spatial compatibility significantly improved drivers' performance in reacting to the divided attention task and making accurate S-R task decision. Drivers' best performance results were obtained for hybrid display with spatial compatibility. Hybrid displays enabled drivers to respond the fastest and achieve the best accuracy in both S-R and divided attention tasks. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Discovery of high affinity anti-ricin antibodies by B cell receptor sequencing and by yeast display of combinatorial VH:VL libraries from immunized animals.

PubMed

Wang, Bo; Lee, Chang-Han; Johnson, Erik L; Kluwe, Christien A; Cunningham, Josephine C; Tanno, Hidetaka; Crooks, Richard M; Georgiou, George; Ellington, Andrew D

2016-01-01

Ricin is a toxin that could potentially be used as a bioweapon. We identified anti-ricin A chain antibodies by sequencing the antibody repertoire from immunized mice and by selecting high affinity antibodies using yeast surface display. These methods led to the isolation of multiple antibodies with high (sub-nanomolar) affinity. Interestingly, the antibodies identified by the 2 independent approaches are from the same clonal lineages, indicating for the first time that yeast surface display can identify native antibodies. The new antibodies represent well-characterized reagents for biodefense diagnostics and therapeutics development.

Generating 3D and 3D-like animations of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs.

PubMed

Hortolà, Policarp

2010-01-01

When dealing with microscopic still images of some kinds of samples, the out-of-focus problem represents a particularly serious limiting factor for the subsequent generation of fully sharp 3D animations. In order to produce fully-focused 3D animations of strongly uneven surface microareas, a vertical stack of six digital secondary-electron SEM micrographs of a human bloodstain microarea was acquired. Afterwards, single combined images were generated using a macrophotography and light microscope image post-processing software. Subsequently, 3D animations of texture and topography were obtained in different formats using a combination of software tools. Finally, a 3D-like animation of a texture-topography composite was obtained in different formats using another combination of software tools. By one hand, results indicate that the use of image post-processing software not concerned primarily with electron micrographs allows to obtain, in an easy way, fully-focused images of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs. On the other hand, results also indicate that such small series of electron micrographs can be utilized for generating 3D and 3D-like animations that can subsequently be converted into different formats, by using certain user-friendly software facilities not originally designed for use in SEM, that are easily available from Internet. Although the focus of this study was on bloodstains, the methods used in it well probably are also of relevance for studying the surface microstructures of other organic or inorganic materials whose sharp displaying is difficult of obtaining from a single SEM micrograph.

Analysis of the binding loops configuration and surface adaptation of different crystallized single-domain antibodies in response to various antigens.

PubMed

Al Qaraghuli, Mohammed M; Ferro, Valerie A

2017-04-01

Monoclonal antibodies have revolutionized the biomedical field through their ubiquitous utilization in different diagnostics and therapeutic applications. Despite this widespread use, their large size and structural complexity have limited their versatility in specific applications. The antibody variable region that is responsible for binding antigen is embodied within domains that can be rescued individually as single-domain antibody (sdAb) fragments. Because of the unique characteristics of sdAbs, such as low molecular weight, high physicochemical stability, and the ability to bind antigens inaccessible to conventional antibodies, they represent a viable alternative to full-length antibodies. Consequently, 149 crystal structures of sdAbs, originating from human (VH), camelids (VHH), or sharks (VNAR), were retrieved from the Protein Data Bank, and their structures were compared. The 3 types of sdAbs displayed complementarity determining regions (CDRs) with different lengths and configurations. CDR3 of the VHH and VNAR domains were dominated by pleated and extended orientations, respectively. Although VNAR showed the smallest average molecular weight and molecular surface area compared with VHH and VH antibodies. However, the solvent accessible surface area measurements of the 3 tested sdAbs types were very similar. All the antihapten VHH antibodies showed pleated CDR3, which were sufficient to create a binding pocket to accommodate haptens (methotrexate and azo dyes) in terms of shape and electrostatic potential. The sdAbs that recognized lysozyme showed more diversity in their CDR3 orientation to enable them to recognize various topographies of lysozyme. Subsequently, the three sdAb classes were different in size and surface area and have shown distinguishable ability to optimize their CDR length and orientation to recognize different antigen classes. Copyright © 2016 John Wiley & Sons, Ltd.

Head-Worn Display Concepts for Surface Operations for Commerical Aircraft

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Bailey, Randall E.; Shelton, Kevin J.; Williams, Steven P.; Kramer, Lynda J.; Norman, Robert M.

2008-01-01

Experiments and flight tests have shown that a Head-Up Display (HUD) and a head-down electronic moving map (EMM) can be enhanced with Synthetic Vision for airport surface operations. While great success in ground operations was demonstrated with a HUD, the research noted that two major HUD limitations during ground operations were its monochrome form and limited, fixed field-of-regard. A potential solution to these limitations found with HUDs may be emerging with Head Worn Displays (HWDs). HWDs are small display devices that may be worn without significant encumbrance to the user. By coupling the HWD with a head tracker, unlimited field-of-regard may be realized. The results of three ground simulation experiments conducted at NASA Langley Research Center are summarized. The experiments evaluated the efficacy of head-worn display applications of Synthetic Vision and Enhanced Vision technology to improve transport aircraft surface operations. The results of the experiments showed that the fully integrated HWD provided greater pilot performance with respect to staying on the path compared to using paper charts alone. Further, when comparing the HWD with the HUD concept, there were no differences in path performance. In addition, the HWD and HUD concepts were rated via paired-comparisons the same in terms of situation awareness and workload.

Construction of the yeast whole-cell Rhizopus oryzae lipase biocatalyst with high activity.

PubMed

Chen, Mei-ling; Guo, Qin; Wang, Rui-zhi; Xu, Juan; Zhou, Chen-wei; Ruan, Hui; He, Guo-qing

2011-07-01

Surface display is effectively utilized to construct a whole-cell biocatalyst. Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast. Here, the cDNA sequence of Rhizopus oryzae lipase (ROL) was optimized and synthesized according to the codon bias of Saccharomyces cerevisiae, and based on the Saccharomyces cerevisiae cell surface display system with α-agglutinin as an anchor, recombinant yeast displaying fully codon-optimized ROL with high activity was successfully constructed. Compared with the wild-type ROL-displaying yeast, the activity of the codon-optimized ROL yeast whole-cell biocatalyst (25 U/g dried cells) was 12.8-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate (pNPP) as the substrate. To our knowledge, this was the first attempt to combine the techniques of yeast surface display and codon optimization for whole-cell biocatalyst construction. Consequently, the yeast whole-cell ROL biocatalyst was constructed with high activity. The optimum pH and temperature for the yeast whole-cell ROL biocatalyst were pH 7.0 and 40 °C. Furthermore, this whole-cell biocatalyst was applied to the hydrolysis of tributyrin and the resulted conversion of butyric acid reached 96.91% after 144 h.

Improved bread-baking process using Saccharomyces cerevisiae displayed with engineered cyclodextrin glucanotransferase.

PubMed

Shim, Jae-Hoon; Seo, Nam-Seok; Roh, Sun-Ah; Kim, Jung-Wan; Cha, Hyunju; Park, Kwan-Hwa

2007-06-13

A bread-baking process was developed using a potential novel enzyme, cyclodextrin glucanotransferase[3-18] (CGTase[3-18]), that had previously been engineered to have enhanced hydrolyzing activity with little cyclodextrin (CD) formation activity toward starch. CGTase[3-18] was primarily manipulated to be displayed on the cell surface of Saccharomyces cerevisiae. S. cerevisiae carrying pdeltaCGT integrated into the chromosome exhibited starch-hydrolyzing activity at the same optimal pH and temperature as the free enzyme. Volumes of the bread loaves and rice cakes prepared using S. cerevisiae/pdeltaCGT increased by 20% and 45%, respectively, with no detectable CD. Retrogradation rates of the bread and rice cakes decreased significantly during storage. In comparison to the wild type, S. cerevisiae/pdeltaCGT showed improved viability during four freeze-thaw cycles. The results indicated that CGTase[3-18] displayed on the surface of yeast hydrolyzed starch to glucose and maltose that can be used more efficiently for yeast fermentation. Therefore, display of an antistaling enzyme on the cell surface of yeast has potential for enhancing the baking process.

Synthetic Vision Enhanced Surface Operations With Head-Worn Display for Commercial Aircraft

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Shelton, Kevin J.; Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Norman, R. M.

2007-01-01

Experiments and flight tests have shown that airport surface operations can be enhanced by using synthetic vision and associated technologies, employed on a Head-Up Display (HUD) and head-down display electronic moving maps (EMM). Although HUD applications have shown the greatest potential operational improvements, the research noted that two major limitations during ground operations were its monochrome form and limited, fixed field-of-regard. A potential solution to these limitations may be the application of advanced Head Worn Displays (HWDs) particularly during low-visibility operations wherein surface movement is substantially limited because of the impaired vision of pilots and air traffic controllers. The paper describes the results of ground simulation experiments conducted at the NASA Langley Research Center. The results of the experiments showed that the fully integrated HWD concept provided significantly improved path performance compared to using paper charts alone. When comparing the HWD and HUD concepts, there were no statistically-significant differences in path performance or subjective ratings of situation awareness and workload. Implications and directions for future research are described.

Oral vaccine of Lactococcus lactis harbouring pandemic H1N1 2009 haemagglutinin1 and nisP anchor fusion protein elevates anti-HA1 sIgA levels in mice.

PubMed

Joan, Stella Siaw Xiu; Pui-Fong, Jee; Song, Adelene Ai-Lian; Chang, Li-Yen; Yusoff, Khatijah; AbuBakar, Sazaly; Rahim, Raha Abdul

2016-05-01

An oral lactococcal-based vaccine which haboured the haemagglutinin1 (HA1) antigen fused to nisP anchor protein for the purpose of surface displaying the HA1 antigen was developed against H1N1 virus. Recombinant L. lactis strains expressed HA1-nisP fusion proteins when induced with nisin, as confirmed through western blotting. However, immunofluorescense did not detect any surface-displayed proteins, suggesting that the protein was either unsuccessfully translocated or improperly displayed. Despite this, oral administration of recombinant L. lactis strains to BALB/c mice revealed that significant levels of anti-HA1 sIgA antibodies were detected in mice fecal suspension samples of mice group NZ9000 (pNZ:HN) when compared to the negative control NZ9000 (pNZ8048) group. Specific anti-HA1 sIgA antibodies were locally produced and live recombinant lactococcal vaccine was able to elicit humoral response of BALB/c mice despite unsuccessful surface display of the HA1 epitope.

Improved delivery of the OVA-CD4 peptide to T helper cells by polymeric surface display on Salmonella

PubMed Central

2014-01-01

Background Autotransporter proteins represent a treasure trove for molecular engineers who modify Gram-negative bacteria for the export or secretion of foreign proteins across two membrane barriers. A particularly promising direction is the development of autotransporters as antigen display or secretion systems. Immunologists have been using ovalbumin as a reporter antigen for years and have developed sophisticated tools to detect specific T cells that respond to ovalbumin. Although ovalbumin-expressing bacteria are being used to trace T cell responses to colonizing or invading pathogens, current constructs for ovalbumin presentation have not been optimized. Results The activation of T helper cells in response to ovalbumin was improved by displaying the OVA-CD4 reporter epitope as a multimer on the surface of Salmonella and fused to the autotransporter MisL. Expression was optimized by including tandem in vivo promoters and two post-segregational killing systems for plasmid stabilization. Conclusions The use of an autotransporter protein to present relevant epitope repeats on the surface of bacteria, combined with additional techniques favoring stable and efficient in vivo transcription, optimizes antigen presentation to T cells. The technique of multimeric epitope surface display should also benefit the development of new Salmonella or other enterobacterial vaccines. PMID:24898796

Cell Adhesion on RGD-Displaying Knottins with Varying Numbers of Tryptophan Amino Acids to Tune the Affinity for Assembly on Cucurbit[8]uril Surfaces.

PubMed

Sankaran, Shrikrishnan; Cavatorta, Emanuela; Huskens, Jurriaan; Jonkheijm, Pascal

2017-09-05

Cell adhesion is studied on multivalent knottins, displaying RGD ligands with a high affinity for integrin receptors, that are assembled on CB[8]-methylviologen-modified surfaces. The multivalency in the knottins stems from the number of tryptophan amino acid moieties, between 0 and 4, that can form a heteroternary complex with cucurbit[8]uril (CB[8]) and surface-tethered methylviologen (MV 2+ ). The binding affinity of the knottins with CB[8] and MV 2+ surfaces was evaluated using surface plasmon resonance spectroscopy. Specific binding occurred, and the affinity increased with the valency of tryptophans on the knottin. Additionally, increased multilayer formation was observed, attributed to homoternary complex formation between tryptophan residues of different knottins and CB[8]. Thus, we were able to control the surface coverage of the knottins by valency and concentration. Cell experiments with mouse myoblast (C2C12) cells on the self-assembled knottin surfaces showed specific integrin recognition by the RGD-displaying knottins. Moreover, cells were observed to elongate more on the supramolecular knottin surfaces with a higher valency, and in addition, more pronounced focal adhesion formation was observed on the higher-valency knottin surfaces. We attribute this effect to the enhanced coverage and the enhanced affinity of the knottins in their interaction with the CB[8] surface. Collectively, these results are promising for the development of biomaterials including knottins via CB[8] ternary complexes for tunable interactions with cells.

Dramatic enhancement of superconductivity in single-crystalline nanowire arrays of Sn

PubMed Central

Zhang, Ying; Wong, Chi Ho; Shen, Junying; Sze, Sin Ting; Zhang, Bing; Zhang, Haijing; Dong, Yan; Xu, Hui; Yan, Zifeng; Li, Yingying; Hu, Xijun; Lortz, Rolf

2016-01-01

Sn is a classical superconductor on the border between type I and type II with critical temperature of 3.7 K. We show that its critical parameters can be dramatically increased if it is brought in the form of loosely bound bundles of thin nanowires. The specific heat displays a pronounced double phase transition at 3.7 K and 5.5 K, which we attribute to the inner ‘bulk’ contribution of the nanowires and to the surface contribution, respectively. The latter is visible only because of the large volume fraction of the surface layer in relation to the bulk volume. The upper transition coincides with the onset of the resistive transition, while zero resistance is gradually approached below the lower transition. In contrast to the low critical field Hc = 0.03 T of Sn in its bulk form, a magnetic field of more than 3 T is required to fully restore the normal state. PMID:27595646

Detail on Dione False color

NASA Image and Video Library

2006-01-27

The leading hemisphere of Dione displays subtle variations in color across its surface in this false color view. To create this view, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superposed over a clear-filter image. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil. Terrain visible here is on the moon's leading hemisphere. North on Dione (1,126 kilometers, or 700 miles across) is up and rotated 17 degrees to the right. All images were acquired with the Cassini spacecraft narrow-angle camera on Dec. 24, 2005 at a distance of approximately 597,000 kilometers (371,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 21 degrees. Image scale is 4 kilometers (2 miles) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA07688

Polarimetric optical imaging of scattering surfaces.

PubMed

Barter, J D; Lee, P H

1996-10-20

A polarimetric optical specular event detector (OSED) has been developed to provide spatially and temporally resolved polarimetric data of backscattering in the visible from water wave surfaces. The OSED acquires simultaneous, two-dimensionally resolved images of the remote target in two orthogonal planes of polarization. With the use of plane-polarized illumination the OSED presently can measure, in an ensemble of breaking waves, the equivalent four-element polarization matrix common to polarimetric radars. Upgrade to full Stokes parameter state of polarization measurements is straightforward with the use of present single-aperture, multi-imager CCD camera technology. The OSED is used in conjunction with a coherent pulse-chirped radar (PCR), which also measures the four-element polarization matrix, to provide direct time-correlated identification of backscattering mechanisms operative during wave-breaking events which heretofore have not been described theoretically. We describe the instrument and its implementation, and examples of spatially resolved polarimetric data are displayed as correlated with the PCR backscatter cross section and polarization ratio records.

Topological Dirac semimetal phase in Pd and Pt oxides

NASA Astrophysics Data System (ADS)

Li, Gang; Yan, Binghai; Wang, Zhijun; Held, Karsten

2017-01-01

Topological Dirac semimetals (DSMs) exhibit nodal points through which energy bands disperse linearly in three-dimensional (3D) momentum space, a 3D analog of graphene. The first experimentally confirmed DSMs with a pair of Dirac points (DPs), Na3Bi and Cd3As2 , show topological surface Fermi arc states and exotic magnetotransport properties, boosting the interest in the search for stable and nontoxic DSM materials. Based on density-functional theory and dynamical mean-field theory calculations, we predict a family of palladium and platinum oxides to be robust 3D DSMs with three pairs of Dirac points that are well separated from bulk bands. The Fermi arcs at the surface display a Lifshitz transition upon a continuous change of the chemical potential. Corresponding oxides are already available as high-quality single crystals, an excellent precondition for the verification of our predictions by photoemission and magnetotransport experiments, extending DSMs to the versatile family of transition-metal oxides.

Dynamic metrology and data processing for precision freeform optics fabrication and testing

NASA Astrophysics Data System (ADS)

Aftab, Maham; Trumper, Isaac; Huang, Lei; Choi, Heejoo; Zhao, Wenchuan; Graves, Logan; Oh, Chang Jin; Kim, Dae Wook

2017-06-01

Dynamic metrology holds the key to overcoming several challenging limitations of conventional optical metrology, especially with regards to precision freeform optical elements. We present two dynamic metrology systems: 1) adaptive interferometric null testing; and 2) instantaneous phase shifting deflectometry, along with an overview of a gradient data processing and surface reconstruction technique. The adaptive null testing method, utilizing a deformable mirror, adopts a stochastic parallel gradient descent search algorithm in order to dynamically create a null testing condition for unknown freeform optics. The single-shot deflectometry system implemented on an iPhone uses a multiplexed display pattern to enable dynamic measurements of time-varying optical components or optics in vibration. Experimental data, measurement accuracy / precision, and data processing algorithms are discussed.

Assessment of Crack Path Prediction in Non-Proportional Mixed-Mode Fatigue

NASA Technical Reports Server (NTRS)

Highsmith, Shelby, Jr.; Johnson, Steve; Swanson, Gregory; Sayyah, Tarek; Pettit, Richard

2008-01-01

Non-proportional mixed-mode loading is present in many systems and a growing crack can experience any manner of mixed-mode loading. Prediction of the resulting crack path is important when assessing potential failure modes or when performing a failure investigation. Current crack path selection criteria are presented along with data for Inconel 718 under non-proportional mixed-mode loading. Mixed-mode crack growth can transition between path deflection mechanisms with very different orientations. Non-proportional fatigue loadings lack a single parameter for input to current crack path criteria. Crack growth transitions were observed in proportional and non-proportional FCG tests. Different paths displayed distinct fracture surface morphologies. New crack path drivers & transition criteria must be developed.

Modeling on the cathodoluminescence properties of the thin film phosphors for field emission flat panel displays

NASA Astrophysics Data System (ADS)

Cho, Kyu-Gong

2000-12-01

In order to investigate the effects of the film roughness with the fundamental luminance parameters of thin film phosphors, Y2 O3:Eu films with different thickness and roughness values were deposited on various substrate materials using a pulsed laser deposition technique under a controlled experimental procedure. The best luminous efficiency was observed from the Y2O3:Eu films on quartz substrates due to the smaller refractive index and low absorption characteristics of the quartz substrates which produce a larger amount of total internal reflection in the film and low loss of light intensity during the multiple internal reflections. The trapped light inside the film can escape the film more easily due to rougher film surface. The better epitaxial growth capability of the Y2O 3:Eu films with the LaAlO3 substrates resulted in higher luminous efficiency in the small surface roughness region. Higher luminous efficiency was observed in reflection mode than in transmission mode due to the contribution of diffusely scattered light at the air-film interface. A new theoretical model based on the diffraction scattering theory of light, the steady-state diffusion condition of carriers and the Kanaya-Okayama's electron- beam-solid interaction range satisfactorily explains all the experimental results mentioned above. The model also provides solid understandings on the cathodoluminescence properties of the thin film phosphors with the effects of other single or multiple luminance parameters. The parameters encountered for the model are surface roughness, electron-beam-solid interaction, surface recombination rate of carriers, charge carrier diffusion properties, multiple scattering at the interfaces (air- film, film-substrate, and substrate-air), optical properties of the material, film thickness, and substrate type. The model supplies a general solution in both qualitative and quantitative ways to estimate the luminance properties of the thin film phosphors and it can be utilized to optimize the thin film phosphor properties for the application of field emission flat panel displays.

Structure-transfection activity relationships in a series of novel cationic lipids with heterocyclic head-groups.

PubMed

Ivanova, Ekaterina A; Maslov, Mikhail A; Kabilova, Tatyana O; Puchkov, Pavel A; Alekseeva, Anna S; Boldyrev, Ivan A; Vlassov, Valentin V; Serebrennikova, Galina A; Morozova, Nina G; Zenkova, Marina A

2013-11-07

Cationic liposomes are promising candidates for the delivery of various therapeutic nucleic acids. Here, we report a convenient synthesis of carbamate-type cationic lipids with various hydrophobic domains (tetradecanol, dialkylglycerol, cholesterol) and positively charged head-groups (pyridinium, N-methylimidazolium, N-methylmorpholinium) and data on the structure-transfection activity relationships. It was found that single-chain lipids possess high surface activity, which correlates with high cytotoxicity due to their ability to disrupt the cellular membrane by combined hydrophobic and electrostatic interactions. Liposomes containing these lipids also display high cytotoxicity with respect to all cell lines. Irrespective of chemical structures, all cationic lipids form liposomes with similar sizes and surface potentials. The characteristics of complexes composed of cationic liposomes and nucleic acids depend mostly on the type of nucleic acid and P/N ratios. In the case of oligodeoxyribonucleotide delivery, the transfection activity depends on the type of cationic head-group regardless of the type of hydrophobic domain: all types of cationic liposomes mediate efficient oligonucleotide transfer into 80-90% of the eukaryotic cells, and liposomes based on lipids with N-methylmorpholinium cationic head-group display the highest transfection activity. In the case of plasmid DNA and siRNA, the type of hydrophobic domain determines the transfection activity: liposomes composed of cholesterol-based lipids were the most efficient in DNA transfer, while liposomes containing glycerol-based lipids exhibited reasonable activity in siRNA delivery under serum-free conditions.

How members of the human gut microbiota overcome the sulfation problem posed by glycosaminoglycans.

PubMed

Cartmell, Alan; Lowe, Elisabeth C; Baslé, Arnaud; Firbank, Susan J; Ndeh, Didier A; Murray, Heath; Terrapon, Nicolas; Lombard, Vincent; Henrissat, Bernard; Turnbull, Jeremy E; Czjzek, Mirjam; Gilbert, Harry J; Bolam, David N

2017-07-03

The human microbiota, which plays an important role in health and disease, uses complex carbohydrates as a major source of nutrients. Utilization hierarchy indicates that the host glycosaminoglycans heparin (Hep) and heparan sulfate (HS) are high-priority carbohydrates for Bacteroides thetaiotaomicron , a prominent member of the human microbiota. The sulfation patterns of these glycosaminoglycans are highly variable, which presents a significant enzymatic challenge to the polysaccharide lyases and sulfatases that mediate degradation. It is possible that the bacterium recruits lyases with highly plastic specificities and expresses a repertoire of enzymes that target substructures of the glycosaminoglycans with variable sulfation or that the glycans are desulfated before cleavage by the lyases. To distinguish between these mechanisms, the components of the B. thetaiotaomicron Hep/HS degrading apparatus were analyzed. The data showed that the bacterium expressed a single-surface endo-acting lyase that cleaved HS, reflecting its higher molecular weight compared with Hep. Both Hep and HS oligosaccharides imported into the periplasm were degraded by a repertoire of lyases, with each enzyme displaying specificity for substructures within these glycosaminoglycans that display a different degree of sulfation. Furthermore, the crystal structures of a key surface glycan binding protein, which is able to bind both Hep and HS, and periplasmic sulfatases reveal the major specificity determinants for these proteins. The locus described here is highly conserved within the human gut Bacteroides , indicating that the model developed is of generic relevance to this important microbial community.

A comparison of tracking with visual and kinesthetic-tactual displays

NASA Technical Reports Server (NTRS)

Jagacinski, R. J.; Flach, J. M.; Gilson, R. D.

1981-01-01

Recent research on manual tracking with a kinesthetic-tactual (KT) display suggests that under appropriate conditions it may be an effective means of providing visual workload relief. In order to better understand how KT tracking differs from visual tracking, both a critical tracking task and stationary single-axis tracking tasks were conducted with and without velocity quickening. On the critical tracking task, the visual displays were superior; however, the KT quickened display was approximately equal to the visual unquickened display. Mean squared error scores in the stationary tracking tasks for the visual and KT displays were approximately equal in the quickened conditions, and the describing functions were very similar. In the unquickened conditions, the visual display was superior. Subjects using the unquickened KT display exhibited a low frequency lead-lag that may be related to sensory adaptation.

Field ion microscopic studies of the CO oxidation on platinum: Field ion imaging and titration reactions

NASA Astrophysics Data System (ADS)

Gorodetskii, V.; Drachsel, W.; Block, J. H.

1994-05-01

Elementary steps of the CO oxidation—which are important for understanding the oscillatory behavior of this catalytic reaction—are investigated simultaneously on different Pt-single crystal surfaces by field ion microscopy. Due to preferential ionization probabilities of oxygen as imaging gas on those surface sites, which are adsorbed with oxygen, these sites can be imaged in a lateral resolution on the atomic scale. In the titration reaction a COad-precovered field emitter surface reacts with gaseous oxygen adsorbed from the gas phase or, vice versa, the Oad-precovered surface with carbon monoxide adsorbed from the gas phase. The competition of the manifold of single crystal planes exposed to the titration reaction at the field emitter tip is studied. The surface specificity can be documented in the specific reaction delay times of the different planes and in the propagation rates of the reaction-diffusion wave fronts measured on these individual planes during the titration reaction with a time resolution of 40 ms. At 300 K the COad-precovered surfaces display the {011} regions, precisely the {331} planes as the most active, followed by {012}, {122}, {001}, and finally by {111}. Reaction wave fronts move with a velocity of 8 Å/s at {012}, with ≊0.8 Å/s at {111}, and have a very fast ``switch-on'' reaction at the (001) plane with 500 Å/s. At higher temperature, T=350 K, an acceleration of reaction rates is combined with shorter delay times. The titration reaction of a precovered Oad surface with COgas at T=373 K shows the formation of CO islands starting in the {011} regions with a quickly moving reaction front into the other surface areas without showing particular delay times for different surface symmetries. The two reverse titration reactions have a largely different character. The titration of COad with oxygen adsorbed from the gas phase consists of three different steps, (i) the induction times, (ii) the highly surface specific reaction, and (iii) different rates of wave front propagation. The reaction of COgas with a precovered Oad layer on the other hand starts with nucleating islands around the {011} planes from where the whole emitter surface is populated with COad without pronounced surface specifity.

Manufacturing Methods and Engineering for TFT Addressed Display.

DTIC Science & Technology

1980-02-20

type required for the Army’s DMD (Digital Message Device), based on an active-matrix addressed electroluminescent display previously developed by...electroluminescent phosphor as the light emitter, and finally packaging or encapsulation. Because of size limitations of the pilot manufacturing facility, the DMD ...display was designed as two identical halves, which were then to be made individually in the auto- mated machine and later assembled into a single DMD

IceT users' guide and reference.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreland, Kenneth D.

2011-01-01

The Image Composition Engine for Tiles (IceT) is a high-performance sort-last parallel rendering library. In addition to providing accelerated rendering for a standard display, IceT provides the unique ability to generate images for tiled displays. The overall resolution of the display may be several times larger than any viewport that may be rendered by a single machine. This document is an overview of the user interface to IceT.

Rapid, Multiplexed Microfluidic Phage Display

DTIC Science & Technology

2012-01-01

affinity phage- displayed peptides for multiple targets in just a single round and without the need for bacterial infection. The chip is shown to be able...by bacterial titer and amplification, and at least two additional rounds of selection. After the final round of biopan- ning, eluted phage are grown on...agar plates, and individual plaques are selected for DNA characterization to determine the amino acid sequence of the phage-displayed peptides. While

Surface modification of SU8 photoresist for shrinkage improvement in a monolithic MEMS microstructure

NASA Astrophysics Data System (ADS)

Chung, C. K.; Hong, Y. Z.

2007-02-01

The effect of O2 plasma treatment on the surface property of exposed and unexposed SU8 photoresist has been investigated for the fabrication of a monolithic MEMS microstructure. It can solve the non-uniformity problem of second resist coating on the SU8 with high intrinsic shrinkage after exposure and post-exposure baking (PEB) in the fabrication of the stacked polymer-metal or polymer-polymer structure, which was used in the application of microfluid, bio and chemistry. The thickness difference of untreated SU8 before PEB between the exposed and unexposed SU8 was about 0.3% while that after PEB increased to about 6%. It could result in large non-uniformity of about 18 µm thickness difference for the following second resist coating on the hydrophobic surface without plasma treatment. The surface property of SU8 in terms of the contact angle and surface energy can be adjusted by O2 plasma treatment for enhancing the coating uniformity of the following resist. The measured contact angles of the exposed and unexposed SU8 decrease with O2 plasma time, corresponding to the increased surface energy determined by the Lifshitz-van der Waals/Lewis acid-base approach. It displayed that the similar hydrophilic surface property can minimize the thickness difference of second resist coating on the first shrunken SU8. A monolithic nozzle plate with a physical resolution of 600 dpi in a single column was demonstrated for an inkjet application based on the improved uniformity.

Biomolecule mediating synthesis of inorganic nanoparticles and their applications

NASA Astrophysics Data System (ADS)

Wei, Zengyan

Project 1. The conventional phage display technique focuses on screening peptide sequences that can bind on target substrates, however the selected peptides are not necessary to nucleate and mediate the growth of the target inorganic crystals, and in many cases they only show moderate affinity to the targets. Here we report a novel phage display approach that can directly screen peptides catalytically growing inorganic nanoparticles in aqueous solution at room temperature. In this study, the phage library is incubated with zinc precursor at room temperature. Among random peptide sequences displayed on phages, those phages that can grow zinc oxide (ZnO) nanoparticles are selected with centrifugation. After several rounds of selection, the peptide sequences displayed on the phage viruses are analyzed by DNA sequencing. Our screening protocol provide a simple and convenient route for the discovery of catalytic peptides that can grow inorganic nanoparticles at room temperature. This novel screening protocol can extend the method on finding a wide range of new catalysts. Project 2. Genetically engineered collagen peptides are assembled into freestanding films when quantum dots (QDs) are co-assembled as joints between collagen domains. These peptide-based films show excellent mechanical properties with Young's modulus of 20 GPa, much larger than most of the multi-composite polymer films and previously reported freestanding nanoparticle-assembled sheets, and it is even close to that reported for the bone tissue in nature. These films show little permanent deformation under small indentation while the mechanical hysteresis becomes remarkable when the load approaches near and beyond the rupture point, which is also characteristic of the bone tissue. Project 3. The shape-controlled synthesis of nanoparticles have been established in single-phase solutions by controlling growth directions of crystalline facets on seed nanocrystals kinetically; however, it is difficult to rationally predict and design nanoparticle shapes. Here we introduce a methodology to fabricate nanoparticles in smaller sizes by evolving shapes thermodynamically. This strategy enables a more rational approach to fabricate shaped nanoparticles by etching specific positions of atoms on facets of seed nanocrystals in reverse micelle reactors where the surface energy gradient induces desorption of atoms on specific locations on the seed surfaces. From seeds of 12 nm palladium nanocubes, the shape is evolved to concave nanocubes and finally hollow nanocages in the size 10 nm by etching the center of {200} facets. The high surface area-to-volume ratio and the exposure of a large number of palladium atoms on ledge and kink sites of hollow nanocages are advantageous to enhance catalytic activity and recyclability.

How Interactive Is the Interactive Whiteboard?

ERIC Educational Resources Information Center

Quashie, Valerie

2009-01-01

An interactive whiteboard (IWB) is simply a surface onto which a computer screen can be displayed, via a projector. It is touch-sensitive and lets one use a pen like a mouse, controlling the computer from the board itself. Everything that can be displayed on a computer can be displayed onto the whiteboard and, if the computer is linked to speakers…

Screening and identification of human ZnT8-specific single-chain variable fragment (scFv) from type 1 diabetes phage display library.

PubMed

Wu, Qian; Wang, Xiaodong; Gu, Yong; Zhang, Xiao; Qin, Yao; Chen, Heng; Xu, Xinyu; Yang, Tao; Zhang, Mei

2016-07-01

Zinc transporter 8 (ZnT8) is a major autoantigen and a predictive marker in type 1 diabetes (T1D). To investigate ZnT8-specific antibodies, a phage display library from T1D was constructed and single-chain antibodies against ZnT8 were screened and identified. Human T1D single-chain variable fragment (scFv) phage display library consists of approximately 1×10(8) clones. After four rounds of bio-panning, seven unique clones were positive by phage ELISA. Among them, C27 and C22, which demonstrated the highest affinity to ZnT8, were expressed in Escherichia coli Top10F' and then purified by affinity chromatography. C27 and C22 specifically bound ZnT8 N/C fusion protein and ZnT8 C terminal dimer with one Arg325Trp mutation. The specificity to human islet cells of these scFvs were further confirmed by immunohistochemistry. In conclusion, we have successfully constructed a T1D phage display antibody library and identified two ZnT8-specific scFv clones, C27 and C22. These ZnT8-specific scFvs are potential agents in immunodiagnostic and immunotherapy of T1D.

Effect of display update interval, update type, and background on perception of aircraft separation on a cockpit display on traffic information

NASA Technical Reports Server (NTRS)

Jago, S.; Baty, D.; Oconnor, S.; Palmer, E.

1981-01-01

The concept of a cockpit display of traffic information (CDTI) includes the integration of air traffic, navigation, and other pertinent information in a single electronic display in the cockpit. Concise display symbology was developed for use in later full-mission simulator evaluations of the CDTI concept. Experimental variables used included the update interval motion of the aircraft, the update type, (that is, whether the two aircraft were updated at the same update interval or not), the background (grid pattern or no background), and encounter type (straight or curved). Only the type of encounter affected performance.

Battery driven 8 channel pulse height analyzer with compact, single gamma-peak display

DOEpatents

Morgan, John P.; Piper, Thomas C.

1991-01-01

The invention comprises a hand-held wand including an l.e.d. display and a aI photomultiplier tube encased in lead or other suitable gamma shielding material, and an electronics and battery back-pack package connected to the wand.

Human factors considerations in the design and evaluation of flight deck displays and controls

DOT National Transportation Integrated Search

2013-11-01

The objective of this effort is to have a single source document for human factors regulatory and guidance material for flight deck displays and controls, in the interest of improving aviation safety. This document identifies guidance on human factor...

Efficiency enhancement of liquid crystal projection displays using light recycle technology

NASA Technical Reports Server (NTRS)

Wang, Y.

2002-01-01

A new technology developed at JPL using low absorption color filters with polarization and color recycle system, is able to enhance efficiency of a single panel liquid crytal display (LCD) projector to the same efficiency of a 3 panel LCD projector.

A signal detection model predicts the effects of set size on visual search accuracy for feature, conjunction, triple conjunction, and disjunction displays

NASA Technical Reports Server (NTRS)

Eckstein, M. P.; Thomas, J. P.; Palmer, J.; Shimozaki, S. S.

2000-01-01

Recently, quantitative models based on signal detection theory have been successfully applied to the prediction of human accuracy in visual search for a target that differs from distractors along a single attribute (feature search). The present paper extends these models for visual search accuracy to multidimensional search displays in which the target differs from the distractors along more than one feature dimension (conjunction, disjunction, and triple conjunction displays). The model assumes that each element in the display elicits a noisy representation for each of the relevant feature dimensions. The observer combines the representations across feature dimensions to obtain a single decision variable, and the stimulus with the maximum value determines the response. The model accurately predicts human experimental data on visual search accuracy in conjunctions and disjunctions of contrast and orientation. The model accounts for performance degradation without resorting to a limited-capacity spatially localized and temporally serial mechanism by which to bind information across feature dimensions.

Transcriptional Networks in Single Perivascular Cells Sorted from Human Adipose Tissue Reveal a Hierarchy of Mesenchymal Stem Cells.

PubMed

Hardy, W Reef; Moldovan, Nicanor I; Moldovan, Leni; Livak, Kenneth J; Datta, Krishna; Goswami, Chirayu; Corselli, Mirko; Traktuev, Dmitry O; Murray, Iain R; Péault, Bruno; March, Keith

2017-05-01

Adipose tissue is a rich source of multipotent mesenchymal stem-like cells, located in the perivascular niche. Based on their surface markers, these have been assigned to two main categories: CD31 - /CD45 - /CD34 + /CD146 - cells (adventitial stromal/stem cells [ASCs]) and CD31 - /CD45 - /CD34 - /CD146 + cells (pericytes [PCs]). These populations display heterogeneity of unknown significance. We hypothesized that aldehyde dehydrogenase (ALDH) activity, a functional marker of primitivity, could help to better define ASC and PC subclasses. To this end, the stromal vascular fraction from a human lipoaspirate was simultaneously stained with fluorescent antibodies to CD31, CD45, CD34, and CD146 antigens and the ALDH substrate Aldefluor, then sorted by fluorescence-activated cell sorting. Individual ASCs (n = 67) and PCs (n = 73) selected from the extremities of the ALDH-staining spectrum were transcriptionally profiled by Fluidigm single-cell quantitative polymerase chain reaction for a predefined set (n = 429) of marker genes. To these single-cell data, we applied differential expression and principal component and clustering analysis, as well as an original gene coexpression network reconstruction algorithm. Despite the stochasticity at the single-cell level, covariation of gene expression analysis yielded multiple network connectivity parameters suggesting that these perivascular progenitor cell subclasses possess the following order of maturity: (a) ALDH br ASC (most primitive); (b) ALDH dim ASC; (c) ALDH br PC; (d) ALDH dim PC (least primitive). This order was independently supported by specific combinations of class-specific expressed genes and further confirmed by the analysis of associated signaling pathways. In conclusion, single-cell transcriptional analysis of four populations isolated from fat by surface markers and enzyme activity suggests a developmental hierarchy among perivascular mesenchymal stem cells supported by markers and coexpression networks. Stem Cells 2017;35:1273-1289. © 2017 AlphaMed Press.

Biological Templating and the Production of Functional Fibers

DTIC Science & Technology

2006-11-01

technique to express designed functional peptides on the virus surface is so-called phage display . It has been widely used to modify the virus surface...and functionality. By using the phage display technique, short peptides containing 2 to 12 random amino acids can be fused into pIII proteins to... M13 filamentous bacteriophage were spun into continuous microfibers. These fibers can be made out of pure phage solution or a blended solution of

A graphics approach in the design of the dual air density Explorer satellites

NASA Technical Reports Server (NTRS)

Mcdougal, D. S.

1975-01-01

A computer program was developed to generate a graphics display of the Dual Air Density (DAD) Explorer satellites which aids in the engineering and scientific design. The program displays a two-dimensional view of both spacecraft and their surface features from any direction. The graphics have been an indispensable tool in the design, analysis, and understanding of the critical locations of the various surface features for both satellites.

Phage display for the discovery of hydroxyapatite-associated peptides.

PubMed

Jin, Hyo-Eon; Chung, Woo-Jae; Lee, Seung-Wuk

2013-01-01

In nature, proteins play a critical role in the biomineralization process. Understanding how different peptide or protein sequences selectively interact with the target crystal is of great importance. Identifying such protein structures is one of the critical steps in verifying the molecular mechanisms of biomineralization. One of the promising ways to obtain such information for a particular crystal surface is to screen combinatorial peptide libraries in a high-throughput manner. Among the many combinatorial library screening procedures, phage display is a powerful method to isolate such proteins and peptides. In this chapter, we will describe our established methods to perform phage display with inorganic crystal surfaces. Specifically, we will use hydroxyapatite as a model system for discovery of apatite-associated proteins in bone or tooth biomineralization studies. This model approach can be generalized to other desired crystal surfaces using the same experimental design principles with a little modification of the procedures. © 2013 Elsevier Inc. All rights reserved.

Biosynthesis, characterisation and antimicrobial activity of silver nanoparticles using Hibiscus rosa-sinensis petals extracts.

PubMed

Nayak, Debasis; Ashe, Sarbani; Rauta, Pradipta Ranjan; Nayak, Bismita

2015-10-01

Green synthesis of metallic nanoparticles has lured the world from the chemical and physical approaches owing to its rapid, non-hazardous and economic aspect of production mechanism. In this study, silver nanoparticles (AgNPs) were synthesised using petal extracts of Hibiscus rosa-sinensis. The AgNPs displayed characteristic surface plasmon resonance peak at around 421 nm having a mean particle size of 76.25±0.17 nm and carried a charge of -41±0.2 mV. The X-ray diffraction patterns displayed typical peaks of face centred cubic crystalline silver. The surface morphology was characterised by scanning electron microscopy and atomic force microscopy. Fourier transform infrared spectroscopy studies confirmed the surface modifications of the functional groups for the synthesis of AgNPs. Furthermore, the synthesised AgNPs displayed proficient antimicrobial activity against pathogenic strains of Vibrio cholerae, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus.

Clinical evaluation of accommodation and ocular surface stability relavant to visual asthenopia with 3D displays

PubMed Central

2014-01-01

Background To validate the association between accommodation and visual asthenopia by measuring objective accommodative amplitude with the Optical Quality Analysis System (OQAS®, Visiometrics, Terrassa, Spain), and to investigate associations among accommodation, ocular surface instability, and visual asthenopia while viewing 3D displays. Methods Fifteen normal adults without any ocular disease or surgical history watched the same 3D and 2D displays for 30 minutes. Accommodative ability, ocular protection index (OPI), and total ocular symptom scores were evaluated before and after viewing the 3D and 2D displays. Accommodative ability was evaluated by the near point of accommodation (NPA) and OQAS to ensure reliability. The OPI was calculated by dividing the tear breakup time (TBUT) by the interblink interval (IBI). The changes in accommodative ability, OPI, and total ocular symptom scores after viewing 3D and 2D displays were evaluated. Results Accommodative ability evaluated by NPA and OQAS, OPI, and total ocular symptom scores changed significantly after 3D viewing (p = 0.005, 0.003, 0.006, and 0.003, respectively), but yielded no difference after 2D viewing. The objective measurement by OQAS verified the decrease of accommodative ability while viewing 3D displays. The change of NPA, OPI, and total ocular symptom scores after 3D viewing had a significant correlation (p < 0.05), implying direct associations among these factors. Conclusions The decrease of accommodative ability after 3D viewing was validated by both subjective and objective methods in our study. Further, the deterioration of accommodative ability and ocular surface stability may be causative factors of visual asthenopia in individuals viewing 3D displays. PMID:24612686

Threat perception while viewing single intruder conflicts on a cockpit display of traffic information

NASA Technical Reports Server (NTRS)

Ellis, S. R.; Palmer, E.

1982-01-01

Subjective estimates of the threat posed by a single intruder aircraft were determined by showing pilots photographs of a cockpit display of traffic information. The time the intruder was away from the point of minimum separation was found to be the major determinant of the perception of threat. When asked to choose a maneuver to reduce the conflict, pilots selected maneuvers with a bias toward those that would have kept the intruders in sight had they been visible out the cockpit window.

Effect of protein properties on display efficiency using the M13 phage display system.

PubMed

Imai, S; Mukai, Y; Takeda, T; Abe, Y; Nagano, K; Kamada, H; Nakagawa, S; Tsunoda, S; Tsutsumi, Y

2008-10-01

The M13 phage display system is a powerful technology for engineering proteins such as functional mutant proteins and peptides. In this system, it is necessary that the protein is displayed on the phage surface. Therefore, its application is often limited when a protein is poorly displayed. In this study, we attempted to understand the relationship between a protein's properties and its display efficiency using the well-known pIII and pVIII type phage display system. The display of positively charged SV40 NLS and HIV-1 Tat peptides on pill was less efficient than that of the neutrally charged RGDS peptide. When different molecular weight proteins (1.5-58 kDa) were displayed on pIII and pVIII, their display efficiencies were directly influenced by their molecular weights. These results indicate the usefulness in predicting a desired protein's compatibility with protein and peptide engineering using the phage display system.

(100) facets of γ-Al2O3: the active surfaces for alcohol dehydration reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwak, Ja Hun; Mei, Donghai; Peden, Charles HF

2011-05-01

Temperature programmed desorption (TPD) of ethanol, and methanol dehydration reaction were studied on γ-Al2O3 in order to identify the catalytic active sites for alcohol dehydration reactions. Two high temperature (> 473 K) desorption features were observed following ethanol adsorption. Samples calcined at T≤473 K displayed a desorption feature in the 523-533 K temperature range, while those calcined at T ≥ 673 K showed a single desorption feature at 498 K. The switch from the high to low temperature ethanol desorption correlated well with the dehydroxylation of the (100) facets of γ-Al2O3 that was predicted at 550 K DFT calculations. Theoreticalmore » DFT simulations of the mechanism of dehydration. on clean and hydroxylated γ-Al2O3(100) surfaces, find that a concerted elimination of ethylene from an ethanol molecule chemisorbed at an Al3+ pentacoordinated site is the rate limiting step for catalytic cycle on both surfaces. Furthermore, titration of the pentacoordinate Al3+ sites on the (100) facets of γ-Al2O3 by BaO completely turned off the methanol dehydration reaction activity. These results unambiguously demonstrate that only the (100) facets on γ-Al2O3 are the catalytic active surfaces for alcohol dehydration.« less

Multimetallic nanosheets: synthesis and applications in fuel cells.

PubMed

Zeb Gul Sial, Muhammad Aurang; Ud Din, Muhammad Aizaz; Wang, Xun

2018-04-03

Two-dimensional nanomaterials, particularly multimetallic nanosheets with single or few atoms thickness, are attracting extensive research attention because they display remarkable advantages over their bulk counterparts, including high electron mobility, unsaturated surface coordination, a high aspect ratio, and distinctive physical, chemical, and electronic properties. In particular, their ultrathin thickness endows them with ultrahigh specific surface areas and a relatively high surface energy, making them highly favorable for surface active applications; for example, they have great potential for a broad range of fuel cell applications. First, the state-of-the-art research on the synthesis of nanosheets with a controlled size, thickness, shape, and composition is described and special emphasis is placed on the rational design of multimetallic nanosheets. Then, a correlation is performed with the performance of multimetallic nanosheets with modified and improved electrochemical properties and high stability, including for the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), formic acid oxidation (FAO), methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), and methanol tolerance are outlined. Finally, some perspectives and advantages offered by this class of materials are highlighted for the development of highly efficient fuel cell electrocatalysts, featuring low cost, enhanced performance, and high stability, which are the key factors for accelerating the commercialization of future promising fuel cells.

Atomic-scale distortions and temperature-dependent large pseudogap in thin films of the parent iron-chalcogenide superconductor Fe1+y Te

NASA Astrophysics Data System (ADS)

Gerbi, Andrea; Buzio, Renato; Kawale, Shrikant; Bellingeri, Emilio; Martinelli, Alberto; Bernini, Cristina; Tresca, Cesare; Capone, Massimo; Profeta, Gianni; Ferdeghini, Carlo

2017-12-01

We investigate with scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) calculations the surface structures and the electronic properties of Fe1+y Te thin films grown by pulsed laser deposition. Contrary to the regular arrangement of antiferromagnetic nanostripes previously reported on cleaved single-crystal samples, the surface of Fe1+y Te thin films displays a peculiar distribution of spatially inhomogeneous nanostripes. Both STM and DFT calculations show the bias-dependent nature of such features and support the interpretation of spin-polarized tunneling between the FeTe surface and an unintentionally magnetized tip. In addition, the spatial inhomogeneity is interpreted as a purely electronic effect related to changes in hybridization and Fe-Fe bond length driven by local variations in the concentration of excess interstitial Fe cations. Unexpectedly, the surface density of states measured by STS strongly evolves with temperature in close proximity to the antiferromagnetic-paramagnetic first-order transition, and reveals a large pseudogap of 180-250 meV at about 50-65 K. We believe that in this temperature range a phase transition takes place, and the system orders and locks into particular combinations of orbitals and spins because of the interplay between excess interstitial magnetic Fe and strongly correlated d-electrons.

A Comprehensive Study of Formic Acid Oxidation on Palladium Nanocrystals with Different Types of Facets and Twin Defects

DOE PAGES

Choi, Sang-Il; Herron, Jeffrey A.; Scaranto, Jessica; ...

2015-04-13

Palladium has been recognized as the best anodic, monometallic electrocatalyst for the formic acid oxidation (FAO) reaction in a direct formic acid fuel cell. Here we report a systematic study of FAO on a variety of Pd nanocrystals, including cubes, right bipyramids, octahedra, tetrahedra, decahedra, and icosahedra. These nanocrystals were synthesized with approximately the same size, but different types of facets and twin defects on their surfaces. Our measurements indicate that the Pd nanocrystals enclosed by {100} facets have higher specific activities than those enclosed by {111} facets, in agreement with prior observations for Pd single-crystal substrates. If comparing nanocrystalsmore » predominantly enclosed by a specific type of facet, {100} or {111}, those with twin defects displayed greatly enhanced FAO activities compared to their single-crystal counterparts. To rationalize these experimental results, we performed periodic, self-consistent DFT calculations on model single-crystal substrates of Pd, representing the active sites present in the nanocrystals used in the experiments. The calculation results suggest that the enhancement of FAO activity on defect regions, represented by Pd(211) sites, compared to the activity of both Pd(100) and Pd(111) surfaces, could be attributed to an increased flux through the HCOO-mediated pathway rather than the COOH-mediated pathway on Pd(211). Since COOH has been identified as a precursor to CO, a site-poisoning species, a lower coverage of CO at the defect regions will lead to a higher activity for the corresponding nanocrystal catalysts, containing those defect regions.« less

Rapid Genotyping of Single Nucleotide Polymorphisms Influencing Warfarin Drug Response by Surface-Enhanced Laser Desorption and Ionization Time-of-Flight (SELDI-TOF) Mass Spectrometry

PubMed Central

Yang, Shangbin; Xu, LiHui; Wu, Haifeng M.

2010-01-01

Warfarin exhibits significant interindividual variability in dosing requirements. Different drug responses are partly attributed to the single nucleotide polymorphisms (SNPs) that influence either drug action or drug metabolism. Rapid genotyping of these SNPs helps clinicians to choose appropriate initial doses to quickly achieve anticoagulation effects and to prevent complications. We report a novel application of surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF MS) in the rapid genotyping of SNPs that impact warfarin efficacy. The SNPs were first amplified by PCR and then underwent single base extension to generate the specific SNP product. Next, genetic variants displaying different masses were bound to Q10 anionic proteinChips and then genotyped by using SELDI-TOF MS in a multiplex fashion. SELDI-TOF MS offered unique properties of on-chip sample enrichment and clean-ups, which streamlined the testing procedures and eliminated many tedious experimental steps required by the conventional MS-based method. The turn-around time for genotyping three known warfarin-related SNPs, CYP2C9*2, CYP2C9*3, and VKORC1 3673G>A by SELDI-TOF MS was less than 5 hours. The analytical accuracy of this method was confirmed both by bidirectional DNA sequencing and by comparing the genotype results (n = 189) obtained by SELDI-TOF MS to reports from a clinical reference laboratory. This new multiplex genotyping method provides an excellent clinical laboratory platform to promote personalized medicine in warfarin therapy. PMID:20075209

Rapid genotyping of single nucleotide polymorphisms influencing warfarin drug response by surface-enhanced laser desorption and ionization time-of-flight (SELDI-TOF) mass spectrometry.

PubMed

Yang, Shangbin; Xu, LiHui; Wu, Haifeng M

2010-03-01

Warfarin exhibits significant interindividual variability in dosing requirements. Different drug responses are partly attributed to the single nucleotide polymorphisms (SNPs) that influence either drug action or drug metabolism. Rapid genotyping of these SNPs helps clinicians to choose appropriate initial doses to quickly achieve anticoagulation effects and to prevent complications. We report a novel application of surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF MS) in the rapid genotyping of SNPs that impact warfarin efficacy. The SNPs were first amplified by PCR and then underwent single base extension to generate the specific SNP product. Next, genetic variants displaying different masses were bound to Q10 anionic proteinChips and then genotyped by using SELDI-TOF MS in a multiplex fashion. SELDI-TOF MS offered unique properties of on-chip sample enrichment and clean-ups, which streamlined the testing procedures and eliminated many tedious experimental steps required by the conventional MS-based method. The turn-around time for genotyping three known warfarin-related SNPs, CYP2C9*2, CYP2C9*3, and VKORC1 3673G>A by SELDI-TOF MS was less than 5 hours. The analytical accuracy of this method was confirmed both by bidirectional DNA sequencing and by comparing the genotype results (n = 189) obtained by SELDI-TOF MS to reports from a clinical reference laboratory. This new multiplex genotyping method provides an excellent clinical laboratory platform to promote personalized medicine in warfarin therapy.

The bedrock electrical conductivity structure of Northern Ireland

NASA Astrophysics Data System (ADS)

Beamish, David

2013-08-01

An airborne geophysical survey of the whole of Northern Ireland has provided over 4.8 M estimates of the bedrock conductivity over the wide range of geological formations present. This study investigates how such data can be used to provide additional knowledge in relation to existing digital geological map information. A by-product of the analysis is a simplification of the spatially aggregated information obtained in such surveys. The methodology used is a GIS-based attribution of the conductivity estimates using a lithological classification of the bedrock formations. A 1:250k geological classification of the data is performed leading to a 56 unit lithological and geostatistical analysis of the conductivity information. The central moments (medians) of the classified data are used to provide a new digital bedrock conductivity map of Northern Ireland with values ranging from 0.32 to 41.36 mS m-1. This baseline map of conductivities displays a strong correspondence with an existing 4 quadrant, chrono-geological description of Northern Ireland. Once defined, the baseline conductivity map allows departures from the norm to be assessed across each specific lithological unit. Bulk electrical conductivity is controlled by a number of petrophysical parameters and it is their variation that is assessed by the procedures employed. The igneous rocks are found to display the largest variability in conductivity values and many of the statistical distributions are multi-modal. A sequence of low-value modes in these data are associated with intrusives within volcanic complexes. These and much older Neoproterzoic rocks appear to represent very low porosity formations that may be the product of rapid cooling during emplacement. By way of contrast, extensive flood basalts (the Antrim lavas) record a well-defined and much higher median value (12.24 mS m-1) although they display complex spatial behaviour in detail. Sedimentary rocks appear to follow the broad behaviours anticipated by standard theoretical descriptions of rock electrical properties that allow for a term due to grain surface conduction (e.g. the presence of clay). Single lithology sedimentary rocks are represented by an increasing set of conductivities through the sequence sandstone (4.91 mS m-1), limestone (8.41 mS m-1) and mudstone (17.85 mS m-1) with argillaceous rocks providing a conductivity of 41.1 mS m-1. In the case of both sandstone and limestone, the single lithology conductivities are significantly less than their mixed lithology counterparts. Mudrocks display a bimodal statistical distribution and an extended analysis of these rocks is carried out across a Carboniferous basin. The results clearly indicate that non-shale mudstones are distinctly less conductive than their shale counterparts. Shale formations display rapid and large movements in conductivity and it is suggested that the observed sensitivity may be due to competing surface conduction effects due to clay and organic material. A study of the variation of conductivity with geological period is also performed. Both a decreasing trend with age and a modulation that peaks in the Triassic period are observed.

Screening by imaging: scaling up single-DNA-molecule analysis with a novel parabolic VA-TIRF reflector and noise-reduction techniques.

PubMed

van 't Hoff, Marcel; Reuter, Marcel; Dryden, David T F; Oheim, Martin

2009-09-21

Bacteriophage lambda-DNA molecules are frequently used as a scaffold to characterize the action of single proteins unwinding, translocating, digesting or repairing DNA. However, scaling up such single-DNA-molecule experiments under identical conditions to attain statistically relevant sample sizes remains challenging. Additionally the movies obtained are frequently noisy and difficult to analyse with any precision. We address these two problems here using, firstly, a novel variable-angle total internal reflection fluorescence (VA-TIRF) reflector composed of a minimal set of optical reflective elements, and secondly, using single value decomposition (SVD) to improve the signal-to-noise ratio prior to analysing time-lapse image stacks. As an example, we visualize under identical optical conditions hundreds of surface-tethered single lambda-DNA molecules, stained with the intercalating dye YOYO-1 iodide, and stretched out in a microcapillary flow. Another novelty of our approach is that we arrange on a mechanically driven stage several capillaries containing saline, calibration buffer and lambda-DNA, respectively, thus extending the approach to high-content, high-throughput screening of single molecules. Our length measurements of individual DNA molecules from noise-reduced kymograph images using SVD display a 6-fold enhanced precision compared to raw-data analysis, reaching approximately 1 kbp resolution. Combining these two methods, our approach provides a straightforward yet powerful way of collecting statistically relevant amounts of data in a semi-automated manner. We believe that our conceptually simple technique should be of interest for a broader range of single-molecule studies, well beyond the specific example of lambda-DNA shown here.

Evaluation of tactual displays for flight control

NASA Technical Reports Server (NTRS)

Levison, W. H.; Tanner, R. B.; Triggs, T. J.

1973-01-01

Manual tracking experiments were conducted to determine the suitability of tactual displays for presenting flight-control information in multitask situations. Although tracking error scores are considerably greater than scores obtained with a continuous visual display, preliminary results indicate that inter-task interference effects are substantially less with the tactual display in situations that impose high visual scanning workloads. The single-task performance degradation found with the tactual display appears to be a result of the coding scheme rather than the use of the tactual sensory mode per se. Analysis with the state-variable pilot/vehicle model shows that reliable predictions of tracking errors can be obtained for wide-band tracking systems once the pilot-related model parameters have been adjusted to reflect the pilot-display interaction.

Light budget and optimization strategies for display applications of dichroic nematic droplet/polymer films

NASA Astrophysics Data System (ADS)

Drzaic, Paul S.

1991-06-01

A detailed light budget is performed on reflective displays made from nematic droplet/polymer (NCAP) films incorporating dichroic dyes. It is shown that the radiance of these displays can be modeled using a simple scheme involving the convolution of the transmission spectra of the various components of the display. Comparisons are made between the relative importance of these optical elements in the display. It is shown that first-surface reflection (glare) is an important factor in reducing the optical performance of these displays, but that the effect of glare can be minimized through the proper choice of dye concentration.

Thin glass substrates for mobile applications

NASA Astrophysics Data System (ADS)

Mauch, Reiner H.; Wegener, Holger; Kruse, Anke; Hildebrand, Norbert

2000-10-01

Flat panel displays play an important role as the visual interface for today's electronic devices (Notebook computers, PDA's, pagers, mobile phones, etc.). Liquid Crystal Display's are dominating the market. While for higher resolution displays active matrix displays like Thin Film Transistor LCD's are used, portable devices are mainly using Super Twisted Nematic (STN) displays. Based on the application, STN displays for mobile applications require thinner glass substrates with improved surface quality at a lower cost. The requirements and trends for STN glass substrates are identified and discussed. Different glass manufacturing processes are used today for the manufacture of these substrates. Advantages and disadvantages of the different glass substrate types are presented and discussed.

Room temperature deposition of gold onto the diffuse and sharp diffraction spot Si(111)-( 3 × 3) R30° Au surfaces

NASA Astrophysics Data System (ADS)

Plass, Richard; Marks, Laurence D.

1996-06-01

Room temperature gold depositions onto Si(111)-( 3 × 3) R30° Au surfaces with diffuse and sharp diffraction spots [Surf. Sci. 242 (1991) 73] (diffuse and sharp 3 × 3 Au hereafter) under UHV conditions has been monitored using transmission electron diffraction (TED). Both systems display an increase in surface structure diffraction spot intensities up to the completion of 1.0 monolayer (ML) after which the surface beams display an exponential decrease in intensity with coverage. The exponential decay rate decreases after roughly 1.33 ML. These results can be attributed to gold initially diffusing to and filling 3 × 3 Au gold trimer sites in vacancy type surface domain walls [Surf. Sci. 342 (1995) 233], then filling one of three possible sites on the 3 × 3 Au structure with essentially no surface diffusion, disrupting nearby gold trimers. Gold deposition onto the diffuse type structure caused the formation and expansion of satellite arcs around the strongest 3 × 3 beams similar to those seen by others [Surf. Sci. 242 (1991) 73; Jpn. J. Appl. Phys. 16 (1977) 891; J. Vac. Sci. Technol. A 10 (1992) 3486] at elevated temperatures while the sharp structure displayed only a modest shoulder formation near the strongest 3 × 3 beams.

Ligand-targeted theranostic nanomedicines against cancer

DOE PAGES

Yao, Virginia J.; D'Angelo, Sara; Butler, Kimberly S.; ...

2016-01-06

Nanomedicines have significant potential for cancer treatment. Although the majority of nanomedicines currently tested in clinical trials utilize simple, biocompatible liposome-based nanocarriers, their widespread use is limited by non-specificity and low target site concentration and thus, do not provide a substantial clinical advantage over conventional, systemic chemotherapy. In the past 20 years, we have identified specific receptors expressed on the surfaces of tumor endothelial and perivascular cells, tumor cells, the extracellular matrix and stromal cells using combinatorial peptide libraries displayed on bacteriophage. These studies corroborate the notion that unique receptor proteins such as IL-11Rα, GRP78, EphA5, among others, are differentiallymore » overexpressed in tumors and present opportunities to deliver tumor-specific therapeutic drugs. By using peptides that bind to tumor-specific cell-surface receptors, therapeutic agents such as apoptotic peptides, suicide genes, imaging dyes or chemotherapeutics can be precisely and systemically delivered to reduce tumor growth in vivo, without harming healthy cells. Given the clinical applicability of peptide-based therapeutics, targeted delivery of nanocarriers loaded with therapeutic cargos seems plausible. We propose a modular design of a functionalized protocell in which a tumor-targeting moiety, such as a peptide or recombinant human antibody single chain variable fragment (scFv), is conjugated to a lipid bilayer surrounding a silica-based nanocarrier core containing a protected therapeutic cargo. The functionalized protocell can be tailored to a specific cancer subtype and treatment regimen by exchanging the tumor-targeting moiety and/or therapeutic cargo or used in combination to create unique, theranostic agents. In this review, we summarize the identification of tumor-specific receptors through combinatorial phage display technology and the use of antibody display selection to identify recombinant human scFvs against these tumor-specific receptors. We compare the characteristics of different types of simple and complex nanocarriers, and discuss potential types of therapeutic cargos and conjugation strategies. As a result, the modular design of functionalized protocells may improve the efficacy and safety of nanomedicines for future cancer therapy.« less

Ligand-targeted theranostic nanomedicines against cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Virginia J.; D'Angelo, Sara; Butler, Kimberly S.

Nanomedicines have significant potential for cancer treatment. Although the majority of nanomedicines currently tested in clinical trials utilize simple, biocompatible liposome-based nanocarriers, their widespread use is limited by non-specificity and low target site concentration and thus, do not provide a substantial clinical advantage over conventional, systemic chemotherapy. In the past 20 years, we have identified specific receptors expressed on the surfaces of tumor endothelial and perivascular cells, tumor cells, the extracellular matrix and stromal cells using combinatorial peptide libraries displayed on bacteriophage. These studies corroborate the notion that unique receptor proteins such as IL-11Rα, GRP78, EphA5, among others, are differentiallymore » overexpressed in tumors and present opportunities to deliver tumor-specific therapeutic drugs. By using peptides that bind to tumor-specific cell-surface receptors, therapeutic agents such as apoptotic peptides, suicide genes, imaging dyes or chemotherapeutics can be precisely and systemically delivered to reduce tumor growth in vivo, without harming healthy cells. Given the clinical applicability of peptide-based therapeutics, targeted delivery of nanocarriers loaded with therapeutic cargos seems plausible. We propose a modular design of a functionalized protocell in which a tumor-targeting moiety, such as a peptide or recombinant human antibody single chain variable fragment (scFv), is conjugated to a lipid bilayer surrounding a silica-based nanocarrier core containing a protected therapeutic cargo. The functionalized protocell can be tailored to a specific cancer subtype and treatment regimen by exchanging the tumor-targeting moiety and/or therapeutic cargo or used in combination to create unique, theranostic agents. In this review, we summarize the identification of tumor-specific receptors through combinatorial phage display technology and the use of antibody display selection to identify recombinant human scFvs against these tumor-specific receptors. We compare the characteristics of different types of simple and complex nanocarriers, and discuss potential types of therapeutic cargos and conjugation strategies. As a result, the modular design of functionalized protocells may improve the efficacy and safety of nanomedicines for future cancer therapy.« less

Identification and binding mechanism of phage displayed peptides with specific affinity to acid-alkali treated titanium.

PubMed

Sun, Yuhua; Tan, Jing; Wu, Baohua; Wang, Jianxin; Qu, Shuxin; Weng, Jie; Feng, Bo

2016-10-01

Acid-alkali treatment is one of means widely used for preparing bioactive titanium surfaces. Peptides with specific affinity to titanium surface modified by acid-alkali two-steps treatment were obtained via phage display technology. Out of the eight new unique peptides, titanium-binding peptide 54 displayed by monoclonal M13 phage at its pIII coat protein (TBP54-M13 phage) was proved to have higher binding affinity to the substrate. The binding interaction occurred at the domain from phenylalanine at position 1 to arginine at position 6 in the sequences of TBP54 (FAETHRGFHFSF) mainly via the reaction of these residues with the Ti surface. Together the coordination and electrostatic interactions controlled the specific binding of the phage to the substrate. The binding affinity was dependent on the surface basic hydroxyl group content. In addition, the phage showed a different interaction way with the Ti surface without acid-alkali treatment along with an impaired affinity. This study could provide more understanding of the interaction mechanism between the selected peptide and its specific substrate, and develop a promising method for the biofunctionalization of titanium. Copyright © 2016 Elsevier B.V. All rights reserved.

Improving genetic immobilization of a cellulase on yeast cell surface for bioethanol production using cellulose.

PubMed

Yang, Jinying; Dang, Hongyue; Lu, Jian Ren

2013-04-01

In this study, Saccharomyces cerevisiae was genetically engineered to harbor the capability of utilizing celluloses for bioethanol production by displaying active cellulolytic enzymes on the cell surface. An endo-1,4-β-glucanase gene egX was cloned from Bacillus pumilus C-9 and its expression products, the EGX cellulases, were displayed on the cell surface of S. cerevisiae by fusing egX with aga2 that encodes the binding subunit of the S. cerevisiae cell wall protein α-agglutinin. To achieve high gene copies and stability, multicopy integration was obtained by integrating the fusion aga2-egX gene into the rDNA region of the S. cerevisiae chromosome. To achieve high expression and surface display efficiency, the aga2-egX gene was expressed under the control of a strong promoter. The presence of the enzymatically active cellulase fusion proteins on the S. cerevisiae cell surface was verified by carboxymethyl cellulase activity assay and immunofluorescence microscopy. This work presented a promising strategy to genetically engineer yeasts to perform efficient fermentation of cellulosic materials for bioethanol production. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-modal cockpit interface for improved airport surface operations

NASA Technical Reports Server (NTRS)

Arthur, Jarvis J. (Inventor); Bailey, Randall E. (Inventor); Prinzel, III, Lawrence J. (Inventor); Kramer, Lynda J. (Inventor); Williams, Steven P. (Inventor)

2010-01-01

A system for multi-modal cockpit interface during surface operation of an aircraft comprises a head tracking device, a processing element, and a full-color head worn display. The processing element is configured to receive head position information from the head tracking device, to receive current location information of the aircraft, and to render a virtual airport scene corresponding to the head position information and the current aircraft location. The full-color head worn display is configured to receive the virtual airport scene from the processing element and to display the virtual airport scene. The current location information may be received from one of a global positioning system or an inertial navigation system.

Engineering of global regulators and cell surface properties toward enhancing stress tolerance in Saccharomyces cerevisiae.

PubMed

Kuroda, Kouichi; Ueda, Mitsuyoshi

2017-12-01

Microbial cell factories are subject to various stresses, leading to the reductions of metabolic activity and bioproduction efficiency. Therefore, the development of stress-tolerant microorganisms is important for improving bio-production efficiency. Recently, modifications of cell surface properties and master regulators have been shown to be effective approaches for enhancing stress tolerance. The cell surface is an attractive target owing to its interactions with the environment and its role in transmitting environmental information. Cell surface engineering in yeast has enabled the convenient modification of cell surface properties. Displaying random peptide libraries and subsequent screening can successfully improve stress tolerance. Furthermore, master regulators including transcription factors are also promising target to be engineered because stress tolerance is determined by many cooperative factors and modification of master regulators can simultaneously affect the expression of multiple downstream genes. The key single amino acid mutations in transcription factors have been identified by analyzing tolerant yeasts that were isolated by adaptive evolution under stress conditions. This enabled the reconstruction of stress-tolerant yeast without burdening cells by introducing the identified mutations. Therefore, for the construction of stress-tolerant yeast from any strains, these two approaches are promising alternatives to conventional overexpression and deletion of stress-related genes. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

14 CFR 255.4 - Display of information.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Display of information. 255.4 Section 255.4 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC... in selecting service options from the database or give single-plane flights a preference over...

14 CFR 255.4 - Display of information.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Display of information. 255.4 Section 255.4 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC... in selecting service options from the database or give single-plane flights a preference over...

14 CFR 255.4 - Display of information.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Display of information. 255.4 Section 255.4 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC... in selecting service options from the database or give single-plane flights a preference over...

Multiple Mice Based Collaborative One-to-One Learning

ERIC Educational Resources Information Center

Infante, Cristian; Hidalgo, Pedro; Nussbaum, Miguel; Alarcon, Rosa; Gottlieb, Andres

2009-01-01

Exchange is a collaborative learning application, originally developed for wirelessly interconnected Pocket PCs, that provides support for students and a teacher performing a face-to-face computer supported collaborative learning (CSCL) activity in a Single Input/Single Display (SISD) mode. We extend the application to support a single display…

Advances in phage display technology for drug discovery.

PubMed

Omidfar, Kobra; Daneshpour, Maryam

2015-06-01

Over the past decade, several library-based methods have been developed to discover ligands with strong binding affinities for their targets. These methods mimic the natural evolution for screening and identifying ligand-target interactions with specific functional properties. Phage display technology is a well-established method that has been applied to many technological challenges including novel drug discovery. This review describes the recent advances in the use of phage display technology for discovering novel bioactive compounds. Furthermore, it discusses the application of this technology to produce proteins and peptides as well as minimize the use of antibodies, such as antigen-binding fragment, single-chain fragment variable or single-domain antibody fragments like VHHs. Advances in screening, manufacturing and humanization technologies demonstrate that phage display derived products can play a significant role in the diagnosis and treatment of disease. The effects of this technology are inevitable in the development pipeline for bringing therapeutics into the market, and this number is expected to rise significantly in the future as new advances continue to take place in display methods. Furthermore, a widespread application of this methodology is predicted in different medical technological areas, including biosensing, monitoring, molecular imaging, gene therapy, vaccine development and nanotechnology.

Corrosion study of single crystal Ni-Mn-Ga alloy and Tb0.27Dy0.73Fe1.95 alloy for the design of new medical microdevices.

PubMed

Pouponneau, Pierre; Savadogo, Oumarou; Napporn, Teko; Yahia, L'Hocine; Martel, Sylvain

2011-02-01

Once placed in a magnetic field, smart magnetic materials (SMM) change their shape, which could be use for the development of smaller minimally invasive surgery devices activated by magnetic field. However, the potential degradation and release of cytotoxic ions by SMM corrosion has to be determined. This paper evaluates the corrosion resistance of two SMM: a single crystal Ni-Mn-Ga alloy and Tb(0.27)Dy(0.73)Fe(1.95) alloy. Ni-Mn-Ga alloy displayed a corrosion potential (E (corr)) of -0.58 V/SCE and a corrosion current density (i (corr)) of 0.43 μA/cm(2). During the corrosion assay, Ni-Mn-Ga sample surface was partially protected; local pits were formed on 20% of the surface and nickel ions were mainly found in the electrolyte. Tb(0.27)Dy(0.73)Fe(1.95) alloy exhibited poor corrosion properties such as E (corr) of -0.87 V/SCE and i (corr) of 5.90 μA/cm(2). During the corrosion test, this alloy was continuously degraded, its surface was impaired by pits and cracks extensively and a high amount of iron ions was measured in the electrolyte. These alloys exhibited low corrosion parameters and a selective degradation in the electrolyte. They could only be used for medical applications if they are coated with high strain biocompatible materials or embedded in composites to prevent direct contact with physiological fluids.

Immersive Visual Data Analysis For Geoscience Using Commodity VR Hardware

NASA Astrophysics Data System (ADS)

Kreylos, O.; Kellogg, L. H.

2017-12-01

Immersive visualization using virtual reality (VR) display technology offers tremendous benefits for the visual analysis of complex three-dimensional data like those commonly obtained from geophysical and geological observations and models. Unlike "traditional" visualization, which has to project 3D data onto a 2D screen for display, VR can side-step this projection and display 3D data directly, in a pseudo-holographic (head-tracked stereoscopic) form, and does therefore not suffer the distortions of relative positions, sizes, distances, and angles that are inherent in 2D projection. As a result, researchers can apply their spatial reasoning skills to virtual data in the same way they can to real objects or environments. The UC Davis W.M. Keck Center for Active Visualization in the Earth Sciences (KeckCAVES, http://keckcaves.org) has been developing VR methods for data analysis since 2005, but the high cost of VR displays has been preventing large-scale deployment and adoption of KeckCAVES technology. The recent emergence of high-quality commodity VR, spearheaded by the Oculus Rift and HTC Vive, has fundamentally changed the field. With KeckCAVES' foundational VR operating system, Vrui, now running natively on the HTC Vive, all KeckCAVES visualization software, including 3D Visualizer, LiDAR Viewer, Crusta, Nanotech Construction Kit, and ProtoShop, are now available to small labs, single researchers, and even home users. LiDAR Viewer and Crusta have been used for rapid response to geologic events including earthquakes and landslides, to visualize the impacts of sealevel rise, to investigate reconstructed paleooceanographic masses, and for exploration of the surface of Mars. The Nanotech Construction Kit is being used to explore the phases of carbon in Earth's deep interior, while ProtoShop can be used to construct and investigate protein structures.

Analysis of Sequence Diversity at the Highly Polymorphic Cpgp40/15 Locus among Cryptosporidium Isolates from Human Immunodeficiency Virus-Infected Children in South Africa

PubMed Central

Leav, Brett A.; Mackay, Malanie R.; Anyanwu, Akudo; O' Connor, Roberta M.; Cevallos, Ana Maria; Kindra, Gurpreet; Rollins, Nigel C.; Bennish, Michael L.; Nelson, Richard G.; Ward, Honorine D.

2002-01-01

Cryptosporidium sp. is a significant cause of diarrheal disease, particularly in human immunodeficiency virus (HIV)-infected patients in developing countries. We recently cloned and sequenced several alleles of the highly polymorphic single-copy Cryptosporidium parvum gene Cpgp40/15. This gene encodes a precursor protein that is proteolytically cleaved to yield mature cell surface glycoproteins gp40 and gp15, which are implicated in zoite attachment to and invasion of enterocytes. The most-striking feature of the Cpgp40/15 alleles and proteins is their unprecedented degree of sequence polymorphism, which is far greater than that observed for any other gene or protein studied in C. parvum to date. In this study we analyzed nucleic acid and amino acid sequence polymorphism at the Cpgp40/15 locus of 20 C. parvum isolates from HIV-infected South African children. Fifteen isolates exhibited one of four previously identified genotype I alleles at the Cpgp40/15 locus (Ia, Ib, Ic, and Id), while five displayed a novel set of polymorphisms that defined a new Cpgp40/15 genotype I allele, designated genotype Ie. Surprisingly, only 15 of these isolates exhibited concordant type I alleles at the thrombospondin-related adhesive protein of Cryptosporidium and Cryptosporidium oocyst wall protein loci, while five isolates (all of which displayed Cpgp40/15 genotype Ic alleles) displayed genotype II alleles at these loci. Furthermore, the last five isolates also manifested chimeric genotype Ic/Ib or Ic/II alleles at the Cpgp40/15 locus, raising the possibility of sexual recombination within and between prototypal parasite genotypes. Lastly, children infected with isolates having genotype Ic alleles were significantly older than those infected with isolates displaying other genotype I alleles. PMID:12065532

Dual-functioning peptides discovered by phage display increase the magnitude and specificity of BMSC attachment to mineralized biomaterials.

PubMed

Ramaraju, Harsha; Miller, Sharon J; Kohn, David H

2017-07-01

Design of biomaterials for cell-based therapies requires presentation of specific physical and chemical cues to cells, analogous to cues provided by native extracellular matrices (ECM). We previously identified a peptide sequence with high affinity towards apatite (VTKHLNQISQSY, VTK) using phage display. The aims of this study were to identify a human MSC-specific peptide sequence through phage display, combine it with the apatite-specific sequence, and verify the specificity of the combined dual-functioning peptide to both apatite and human bone marrow stromal cells. In this study, a combinatorial phage display identified the cell binding sequence (DPIYALSWSGMA, DPI) which was combined with the mineral binding sequence to generate the dual peptide DPI-VTK. DPI-VTK demonstrated significantly greater binding affinity (1/K D ) to apatite surfaces compared to VTK, phosphorylated VTK (VTK phos ), DPI-VTK phos , RGD-VTK, and peptide-free apatite surfaces (p < 0.01), while significantly increasing hBMSC adhesion strength (τ 50 , p < 0.01). MSCs demonstrated significantly greater adhesion strength to DPI-VTK compared to other cell types, while attachment of MC3T3 pre-osteoblasts and murine fibroblasts was limited (p < 0.01). MSCs on DPI-VTK coated surfaces also demonstrated increased spreading compared to pre-osteoblasts and fibroblasts. MSCs cultured on DPI-VTK coated apatite films exhibited significantly greater proliferation compared to controls (p < 0.001). Moreover, early and late stage osteogenic differentiation markers were elevated on DPI-VTK coated apatite films compared to controls. Taken together, phage display can identify non-obvious cell and material specific peptides to increase human MSC adhesion strength to specific biomaterial surfaces and subsequently increase cell proliferation and differentiation. These new peptides expand biomaterial design methodology for cell-based regeneration of bone defects. This strategy of combining cell and material binding phage display derived peptides is broadly applicable to a variety of systems requiring targeted adhesion of specific cell populations, and may be generalized to the engineering of any adhesion surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pilot Preferences on Displayed Aircraft Control Variables

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.; Gregory, Irene M.

2013-01-01

The experiments described here explored how pilots want available maneuver authority information transmitted and how this information affects pilots before and after an aircraft failure. The aircraft dynamic variables relative to flight performance were narrowed to energy management variables. A survey was conducted to determine what these variables should be. Survey results indicated that bank angle, vertical velocity, and airspeed were the preferred variables. Based on this, two displays were designed to inform the pilot of available maneuver envelope expressed as bank angle, vertical velocity, and airspeed. These displays were used in an experiment involving control surface failures. Results indicate the displayed limitations in bank angle, vertical velocity, and airspeed were helpful to the pilots during aircraft surface failures. However, the additional information did lead to a slight increase in workload, a small decrease in perceived aircraft flying qualities, and no effect on aircraft situation awareness.

Three-dimensional modeling of light rays on the surface of a slanted lenticular array for autostereoscopic displays.

PubMed

Jung, Sung-Min; Kang, In-Byeong

2013-08-10

In this paper, we developed an optical model describing the behavior of light at the surface of a slanted lenticular array for autostereoscopic displays in three dimensions and simulated the optical characteristics of autostereoscopic displays using the Monte Carlo method under actual design conditions. The behavior of light is analyzed by light rays for selected inclination and azimuthal angles; numerical aberrations and conditions of total internal reflection for the lenticular array were found. The intensity and the three-dimensional crosstalk distributions calculated from our model coincide very well with those from conventional design software, and our model shows highly enhanced calculation speed that is 67 times faster than that of the conventional software. From the results, we think that the optical model is very useful for predicting the optical characteristics of autostereoscopic displays with enhanced calculation speed.

Tomato bushy stunt virus (TBSV), a versatile platform for polyvalent display of antigenic epitopes and vaccine design.

PubMed

Kumar, Shantanu; Ochoa, Wendy; Singh, Pratik; Hsu, Catherine; Schneemann, Anette; Manchester, Marianne; Olson, Mark; Reddy, Vijay

2009-05-25

Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of foreign epitopes of interest on their capsid surface to improve their presentation enhancing the antigenicity and host immune response. In the present study, we used the VLPs of Tomato bushy stunt virus (TBSV), an icosahedral plant virus, as a platform to display 180 copies of 16 amino acid epitopes of ricin toxin fused to the C-terminal end of a modified TBSV capsid protein (NDelta52). Expression of the chimeric recombinant protein in insect cells resulted in spontaneous assembly of VLPs displaying the ricin epitope. Cryo-electron microscopy and image reconstruction of the chimeric VLPs at 22 A resolution revealed the locations and orientation of the ricin epitope exposed on the TBSV capsid surface. Furthermore, injection of chimeric VLPs into mice generated antisera that detected the native ricin toxin. The ease of fusing of short peptides of 15-20 residues and their ability to form two kinds (T=1, T=3) of bio-nanoparticles that result in the display of 60 or 180 copies of less constrained and highly exposed antigenic epitopes makes TBSV an attractive and versatile display platform for vaccine design.

Sublethal exposure to methoxyfenozide-treated surfaces reduces the attractiveness and responsiveness in adult oriental fruit moth (Lepidoptera: Tortricidae).

PubMed

Reinke, Michael D; Barrett, Bruce A

2007-02-01

The chemical communication (female attractiveness and male responsiveness) of adult oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide for 48 h were investigated in two laboratory wind tunnel assays. The recapture assay examined the ability of treated males to orient to a single cage of treated females, and the data gathered were mean percentage of males recaptured per treatment. The male sexual behavior assay examined some specific orientation behaviors (associated with sexual excitability) of treated males when they were given a choice of two competing pheromone sources (cages of treated females), and the data gathered were mean time males spent in upwind plume orientations and at source contact (female cage) per treatment. Data from the recapture assay suggests that exposure to methoxyfenozide impacts male responsiveness more than female attractiveness. In contrast, data from the sexual behavior assay strongly revealed that exposure to methoxyfenozide-treated surfaces does negatively impact both the ability of calling females to attract males and of aroused males to display sustained upwind flight behavior and time spent at the female cages.

High-resolution heat-transfer-coefficient maps applicable to compound-curve surfaces using liquid crystals in a transient wind tunnel

NASA Technical Reports Server (NTRS)

Jones, Terry V.; Hippensteele, Steven A.

1988-01-01

Tests were performed in a transient heat transfer tunnel in which the model under test was preheated prior to allowing room temperature air to be suddenly drawn over the model. The resulting movement of isothermal contours on the model is revealed using a surface coating of thermochromic liquid crystals that display distinctive colors at particular temperatures. A video record is obtained of a temperature and time data pair for all points on the model during a single test. Experiments on a duct model are reported in which the model was preheated using a hot air stream. A manner in which initial model temperature nonuniformities could be taken into account was investigated. The duct model was also tested with a steady-state measurement technique and results were compared with the transient measurements, but recognizing that differences existed between the upstream thermal boundary conditions. The steady-state and transient measurements were shown to be consistent with predicted values. The main advantage of this transient heat transfer technique using liquid crystals is that since the test model need not be actively heated, high-resolution measurements on surfaces with complex shapes may be obtained.

[A heart function measuring and analyzing instrument based on single-chip microcomputer].

PubMed

Rong, Z; Liang, H; Wang, S

1999-05-01

An Introduction a measuring and analyzing instrument, based on the single-chip microcomputer, which provides sample gathering, processing, controlling, adjusting, keyboard and printing. All informations are provided and displayed in Chinese.

Surface display of roGFP for monitoring redox status of extracellular microenvironments in Shewanella oneidensis biofilms.

PubMed

Sivakumar, Krishnakumar; Mukherjee, Manisha; Cheng, Hsin-I; Zhang, Yingdan; Ji, Lianghui; Cao, Bin

2015-03-01

Biofilms are the most ubiquitous and resilient form of microbial life on earth. One most important feature of a biofilm is the presence of a self-produced matrix, which creates highly heterogeneous and dynamic microenvironments within biofilms. Redox status in biofilm microenvironments plays a critical role in biofilm development and function. However, there is a lack of non-intrusive tools to quantify extracellular redox status of microenvironments within a biofilm matrix. In this study, using Shewanella oneidensis as a model organism, we demonstrated a novel approach to monitor extracellular redox status in biofilm microenvironments. Specifically, we displayed a redox sensitive fluorescence protein roGFP onto the cell surface of S. oneidensis by fusing it to the C-terminus of BpfA, a large surface protein, and used the surface displayed roGFP as a sensor to quantify the extracellular redox status in the matrix of S. oneidensis biofilms. The fusion of roGFP into BpfA has no negative impacts on cell growth and biofilm formation. Upon exposure to oxidizing agents such as H2 O2 , Ag(+) , and SeO3 (2-) , S. oneidensis BpfA-roGFP cells exhibited a characteristic fluorescence of roGFP. Proteinase treatment assay and super-resolution structured illumination microscopy confirmed the surface localization of BpfA-roGFP. We further used the surface displayed roGFP monitored the extracellular redox status in the matrix at different depths of a biofilm exposed to H2 O2 . This study provides a novel approach to non-invasively monitor extracellular redox status in microenvironments within biofilms, which can be used to understand redox responses of biofilms to environmental perturbations. © 2014 Wiley Periodicals, Inc.

Two graphical user interfaces for managing and analyzing MODFLOW groundwater-model scenarios

USGS Publications Warehouse

Banta, Edward R.

2014-01-01

Scenario Manager and Scenario Analyzer are graphical user interfaces that facilitate the use of calibrated, MODFLOW-based groundwater models for investigating possible responses to proposed stresses on a groundwater system. Scenario Manager allows a user, starting with a calibrated model, to design and run model scenarios by adding or modifying stresses simulated by the model. Scenario Analyzer facilitates the process of extracting data from model output and preparing such display elements as maps, charts, and tables. Both programs are designed for users who are familiar with the science on which groundwater modeling is based but who may not have a groundwater modeler’s expertise in building and calibrating a groundwater model from start to finish. With Scenario Manager, the user can manipulate model input to simulate withdrawal or injection wells, time-variant specified hydraulic heads, recharge, and such surface-water features as rivers and canals. Input for stresses to be simulated comes from user-provided geographic information system files and time-series data files. A Scenario Manager project can contain multiple scenarios and is self-documenting. Scenario Analyzer can be used to analyze output from any MODFLOW-based model; it is not limited to use with scenarios generated by Scenario Manager. Model-simulated values of hydraulic head, drawdown, solute concentration, and cell-by-cell flow rates can be presented in display elements. Map data can be represented as lines of equal value (contours) or as a gradated color fill. Charts and tables display time-series data obtained from output generated by a transient-state model run or from user-provided text files of time-series data. A display element can be based entirely on output of a single model run, or, to facilitate comparison of results of multiple scenarios, an element can be based on output from multiple model runs. Scenario Analyzer can export display elements and supporting metadata as a Portable Document Format file.

Note: Laser beam scanning using a ferroelectric liquid crystal spatial light modulator

NASA Astrophysics Data System (ADS)

Das, Abhijit; Boruah, Bosanta R.

2014-04-01

In this work we describe laser beam scanning using a ferroelectric liquid crystal spatial light modulator. Commercially available ferroelectric liquid crystal spatial light modulators are capable of displaying 85 colored images in 1 s using a time dithering technique. Each colored image, in fact, comprises 24 single bit (black and white) images displayed sequentially. We have used each single bit image to write a binary phase hologram. For a collimated laser beam incident on the hologram, one of the diffracted beams can be made to travel along a user defined direction. We have constructed a beam scanner employing the above arrangement and demonstrated its use to scan a single laser beam in a laser scanning optical sectioning microscope setup.