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Sample records for tandem kappab enhancer

  1. Crystal Structure of NFAT Bound to the HIV-1 LTR Tandem ?B Enhancer Element

    SciTech Connect

    Bates, Darren L.; Barthel, Kristen K.B.; Wu, Yongqing; Kalhor, Reza; Stroud, James C.; Giffin, Michael J.; Chen, Lin

    2008-05-27

    Here, we have determined the crystal structure of the DNA binding domain of NFAT bound to the HIV-1 long terminal repeat (LTR) tandem {kappa}B enhancer element of 3.05 {angstrom} resolution. NFAT binds as a dimer to the upstream {kappa}B site (Core II), but as a monomer to the 3' end of the downstream {kappa}B site (Core I). The DNA shows a significant bend near the 5' end of Core I, where a lysine residue from NFAT bound to the 3' end of Core II inserts into the minor groove and seems to cause DNA bases to flip out. Consistent with this structural feature, the 5' end of Core I become hypersensitive to dimethylsulfate in the in vivo footprinting upon transcriptional activation of the HIV-1 LTR. Our studies provide a basis for futher investigating the functional mechanism of NFAT in HIV-1 transcription and replication.

  2. A new member of the I kappaB protein family, I kappaB epsilon, inhibits RelA (p65)-mediated NF-kappaB transcription.

    PubMed Central

    Li, Z; Nabel, G J

    1997-01-01

    A novel member of the I kappaB family has been identified as a protein that associated with the p50 subunit of NF-kappaB in a yeast two-hybrid screen. Similar to previously known I kappaB proteins, this member, I kappaB epsilon, has six consecutive ankyrin repeats. I kappaB epsilon mRNA is widely expressed in different human tissues, with highest levels in spleen, testis, and lung. I kappaB epsilon interacts with different NF-kappaB proteins, including p65 (RelA), c-Rel, p50, and p52, in vitro and in vivo and inhibits the DNA-binding activity of both p50-p65 and p50-c-Rel complexes effectively. Endogenous and transfected NF-kappaB (RelA-dependent) transcriptional activation is inhibited by I kappaB epsilon. I kappaB epsilon mRNA is expressed at different levels in specific cell types and is synthesized constitutively in transformed B-cell lines. It also displays differential induction in response to tumor necrosis factor alpha, interleukin-1, or phorbol ester stimulation compared to I kappaB alpha in non-B-cell lines. Therefore, I kappaB epsilon represents a novel I kappaB family member which provides an alternative mechanism for regulation of NF-kappaB-dependent transcription. PMID:9315679

  3. Hybrid tandem solar cell enhanced by a metallic hole-array as the intermediate electrode.

    PubMed

    Zhang, Xuanru; Huang, Qiuping; Hu, Jigang; Knize, Randy J; Lu, Yalin

    2014-10-20

    A metallic hole-array structure was inserted into a tandem solar cell structure as an intermediate electrode, which allows a further fabrication of a novel and efficient hybrid organic-inorganic tandem solar cell. The inserted hole-array layer reflects the higher-energy photons back to the top cell, and transmits lower-energy photons to the bottom cell via the extraordinary optical transmission (EOT) effect. In this case light absorption in both top and bottom subcells can be simultaneously enhanced via both structural and material optimizations. Importantly, this new design could remove the constraints of requiring lattice-matching and current-matching between the used two cascaded subcells in a conventional tandem cell structure, and therefore, the tunnel junction could be no longer required. As an example, a novel PCBM/CIGS tandem cell was designed and investigated. A systematic modeling study was made on the structural parameter tuning, with the period ranging from a few hundreds nanometers to over one micrometer. Surface plasmon polaritons, magnetic plasmon polaritons, localized surface plasmons, and optical waveguide modes were found to participate in the EOT and the light absorption enhancement. Impressively, more than 40% integrated power enhancement can be achieved in a variable structural parameter range. PMID:25607297

  4. Ozone enhances diesel exhaust particles (DEP)-induced interleukin-8 (IL-8) gene expression in human airway epithelial cells through activation of nuclear factors- kappaB (NF-kappaB) and IL-6 (NF-IL6).

    PubMed

    Kafoury, Ramzi M; Kelley, James

    2005-12-01

    Ozone, a highly reactive oxidant gas is a major component of photochemical smog. As an inhaled toxicant, ozone induces its adverse effects mainly on the lung. Inhalation of particulate matter has been reported to cause airway inflammation in humans and animals. Furthermore, epidemiological evidence has indicated that exposure to particulate matter (PM[2.5-10]), including diesel exhaust particles (DEP) has been correlated with increased acute and chronic respiratory morbidity and exacerbation of asthma. Previously, exposure to ozone or particulate matter and their effect on the lung have been addressed as separate environmental problems. Ozone and particulate matter may be chemically coupled in the ambient air. In the present study we determined whether ozone exposure enhances DEP effect on interleukin-8 (IL-8) gene expression in human airway epithelial cells. We report that ozone exposure (0.5 ppm x 1 hr) significantly increased DEP-induced IL-8 gene expression in A549 cells (117 +/- 19 pg/ml, n = 6, p < 0.05) as compared to cultures treated with DEP (100 microg/ml x 4 hr) alone (31 +/- 3 pg/ml, n = 6), or cultures exposed to purified air (24 +/- 6 pg/ml, n = 6). The increased DEP-induced IL-8 gene expression following ozone exposure was attributed to ozone-induced increase in the activity of the transcription factors NF-kappaB and NF-IL6. The results of the present study indicate that ozone exposure enhances the toxicity of DEP in human airway epithelial cells by augmenting IL-8 gene expression, a potent chemoattractant of neutrophils in the lung. PMID:16819095

  5. Thrust Enhancement of Flapping Wings in Tandem and Biplane Configurations by Pure Plunging Motion

    NASA Astrophysics Data System (ADS)

    Yilmaz, S. Banu; Sahin, Mehmet; Unal, M. Fevzi

    2012-11-01

    The propulsion performance of flapping NACA0012 airfoils undergoing harmonic plunging motion in tandem and biplane wing configurations is investigated numerically. An unstructured finite volume solver based on Arbitrary Lagrangian-Eulerian formulation is utilized in order to solve the incompressible unsteady Navier-Stokes equations. Four different tandem and four different biplane wing combinations are considered. Various instantaneous and time-averaged aerodynamic parameters including lift and drag coefficients, vorticity contours and streamlines are calculated for each case and compared with each other. As a reference the single wing case corresponding to the deflected jet phenomenon in Jones and Platzer (Exp. Fluids 46:799-810, 2009) is also studied. In these simulations, the Reynolds number is chosen as 252, the reduced frequency of plunging motion (k = 2 ?f /U?) is 12.3 and the plunge amplitude non-dimensionalized with respect to chord is 0.12. The solutions of the single wing case indicate dependence on the location of start-up vortices. Meanwhile the multiple wing configurations indicate that the highest thrust enhancement is obtained in one of the biplane cases where the two wings closely moving towards each other namely biplane asynchronous-closer case.

  6. Performance enhancement of existing two-stage sounding rocket vehicles through the use of tandem booster systems

    NASA Technical Reports Server (NTRS)

    Flores, C. C.; Gurkin, L. W.

    1982-01-01

    The three-stage Taurus-Nike-Tomahawk launch vehicle is being considered for performance enhancement of the existing Taurus-Tomahawk flight system. In addition, performance enhancement of other existing two-stage launch vehicles is being considered through the use of tandem booster systems. Aeroballistic characteristics of the proposed Taurus-Nike-Tomahawk vehicle are presented, as are overall performance capabilities of other potential three-stage flight systems.

  7. MEASUREMENT OF PYRETHROID RESIDUES IN ENVIRONMENTAL AND FOOD SAMPLES BY ENHANCED SOLVENT EXTRACTION/SUPERCRITICAL FLUID EXTRACTION COUPLED WITH GAS CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    The abstract summarizes pyrethorid methods development research. It provides a summary of sample preparation and analytical techniques such as supercritical fluid extraction, enhance solvent extraction, gas chromatography and tandem mass spectrometry.

  8. Performance enhancement in a-Si:H/?c-Si:H tandem solar cells with periodic microstructured surfaces.

    PubMed

    Shen, Xiangqian; Wang, Qingkang; Wangyang, Peihua; Huang, Kun; Chen, Le; Liu, Daiming

    2015-04-01

    Here we report on an efficient light-coupling scheme with a periodic microstructured surface to enhance the performance of thin film silicon solar cells. The centerpiece of the surface structure is the hemispherical pit arrays (HPAs), which are fabricated using an inexpensive and scalable process. The integration of HPAs into micromorph tandem thin film silicon solar cells leads to superior broadband reflection suppression properties. With this design, the reflection losses of the tandem cell are reduced to only 1.5%. We demonstrate an efficiency increase from 11.67% to 12.23% compared to a conventional cell with a flat surface, with a 4.6% increase in short circuit current density. The surface microstructures reported here can be applied to a variety of photovoltaic devices to further improve their performance. PMID:25831315

  9. Ion Mobility Tandem Mass Spectrometry Enhances Performance of Bottom-up Proteomics

    PubMed Central

    Helm, Dominic; Vissers, Johannes P. C.; Hughes, Christopher J.; Hahne, Hannes; Ruprecht, Benjamin; Pachl, Fiona; Grzyb, Arkadiusz; Richardson, Keith; Wildgoose, Jason; Maier, Stefan K.; Marx, Harald; Wilhelm, Mathias; Becher, Isabelle; Lemeer, Simone; Bantscheff, Marcus; Langridge, James I.; Kuster, Bernhard

    2014-01-01

    One of the limiting factors in determining the sensitivity of tandem mass spectrometry using hybrid quadrupole orthogonal acceleration time-of-flight instruments is the duty cycle of the orthogonal ion injection system. As a consequence, only a fraction of the generated fragment ion beam is collected by the time-of-flight analyzer. Here we describe a method utilizing postfragmentation ion mobility spectrometry of peptide fragment ions in conjunction with mobility time synchronized orthogonal ion injection leading to a substantially improved duty cycle and a concomitant improvement in sensitivity of up to 10-fold for bottom-up proteomic experiments. This enabled the identification of 7500 human proteins within 1 day and 8600 phosphorylation sites within 5 h of LC-MS/MS time. The method also proved powerful for multiplexed quantification experiments using tandem mass tags exemplified by the chemoproteomic interaction analysis of histone deacetylases with Trichostatin A. PMID:25106551

  10. Enhanced absorption in tandem solar cells by applying hydrogenated In2O3 as electrode

    NASA Astrophysics Data System (ADS)

    Yin, Guanchao; Steigert, Alexander; Manley, Phillip; Klenk, Reiner; Schmid, Martina

    2015-11-01

    To realize the high efficiency potential of perovskite/chalcopyrite tandem solar cells in modules, hydrogenated In2O3 (IO:H) as electrode is investigated. IO:H with an electron mobility of 100 cm2 V-1 s-1 is demonstrated. Compared to the conventional Sn doped In2O3 (ITO), IO:H exhibits a decreased electron concentration and leads to almost no sub-bandgap absorption up to the wavelength of 1200 nm. Without a trade-off between transparency and lateral resistance in the IO:H electrode, the tandem cell keeps increasing in efficiency as the IO:H thickness increases and efficiencies above 22% are calculated. In contrast, the cells with ITO as electrode perform much worse due to the severe parasitic absorption in ITO. This indicates that IO:H has the potential to lead to high efficiencies, which is otherwise constrained by the parasitic absorption in conventional transparent conductive oxide electrode for tandem solar cells in modules.

  11. Correction of errors in tandem mass spectrum extraction enhances phosphopeptide identification.

    PubMed

    Hao, Piliang; Ren, Yan; Tam, James P; Sze, Siu Kwan

    2013-12-01

    The tandem mass spectrum extraction of phosphopeptides is more difficult and error-prone than that of unmodified peptides due to their lower abundance, lower ionization efficiency, the cofragmentation with other high-abundance peptides, and the use of MS(3) on MS(2) fragments with neutral losses. However, there are still no established methods to evaluate its correctness. Here we propose to identify and correct these errors via the combinatorial use of multiple spectrum extraction tools. We evaluated five free and two commercial extraction tools using Mascot and phosphoproteomics raw data from LTQ FT Ultra, in which RawXtract 1.9.9.2 identified the highest number of unique phosphopeptides (peptide expectation value <0.05). Surprisingly, ProteoWizzard (v. 3.0.3476) extracted wrong precursor mass for most MS(3) spectra. Comparison of the top three free extraction tools showed that only 54% of the identified spectra were identified consistently from all three tools, indicating that some errors might happen during spectrum extraction. Manual check of 258 spectra not identified from all three tools revealed 405 errors of spectrum extraction with 7.4% in selecting wrong precursor charge, 50.6% in selecting wrong precursor mass, and 42.1% in exporting MS/MS fragments. We then corrected the errors by selecting the best extracted MGF file for each spectrum among the three tools for another database search. With the errors corrected, it results in the 22.4 and 12.2% increase in spectrum matches and unique peptide identification, respectively, compared with the best single method. Correction of errors in spectrum extraction improves both the sensitivity and confidence of phosphopeptide identification. Data analysis on nonphosphopeptide spectra indicates that this strategy applies to unmodified peptides as well. The identification of errors in spectrum extraction will promote the improvement of spectrum extraction tools in future. PMID:24147958

  12. Pulsed Multiple Reaction Monitoring Approach to Enhancing Sensitivity of a Tandem Quadrupole Mass Spectrometer

    SciTech Connect

    Belov, Mikhail E.; Prasad, Satendra; Prior, David C.; Danielson, William F.; Weitz, Karl K.; Ibrahim, Yehia M.; Smith, Richard D.

    2011-02-23

    Liquid chromatography (LC)-triple quadrupole mass spectrometers operating in a Multiple Reaction Monitoring (MRM) mode are increasingly used for quantitative analysis of low abundance analytes in highly complex biochemical matrices. After development and selection of optimum MRM transition, sensitivity and data quality limitations are largely related to mass spectral peak interferences from sample or matrix constituents and statistical limitations at low number of ions reaching the detector. Herein, we report a new approach to enhancing MRM sensitivity by converting the continuous stream of ions from the ion source into a pulsed ion beam through the use of an Ion Funnel Trap (IFT). Evaluation of the pulsed MRM approach was performed with a tryptic digest of Shewanella oneidensis strain MR-1 spiked with several reference peptides. The sensitivity improvement observed with the IFT coupled to the triple quadrupole instrument is based on several unique features. First, ion accumulation in the radio frequency (RF) ion trap facilitates improved droplet desolvation, which is manifested in the reduced background ion noise at the detector. Second, signal amplitude for a given transition is enhanced because of an order-of-magnitude increase in the ion charge density per unit time compared to a continuous mode of operation. Third, signal detection at the full duty cycle is obtained, as the trap use eliminates dead times between transitions, which are inevitable with continuous ion streams. In comparison with the conventional approach, the pulsed MRM signals showed up to 5-fold enhanced peak amplitude and 2-3 fold reduced chemical background, resulting in an improvement in the limit of detection (LOD) by a factor of ~ 4 to ~ 8.

  13. Tandem tracking

    USGS Multimedia Gallery

    Biologist Sabrina Davenport tandem tracks the Lower Missouri River during high water on June 2, 2011.  Two boats (note boat out window) tracking in tandem can detect fish effectively across a wider river and can turn to search behind wing dikes and sandbars where sturgeon can hide during h...

  14. Current matching using CdSe quantum dots to enhance the power conversion efficiency of InGaP/GaAs/Ge tandem solar cells.

    PubMed

    Lee, Ya-Ju; Yao, Yung-Chi; Tsai, Meng-Tsan; Liu, An-Fan; Yang, Min-De; Lai, Jiun-Tsuen

    2013-11-01

    A III-V multi-junction tandem solar cell is the most efficient photovoltaic structure that offers an extremely high power conversion efficiency. Current mismatching between each subcell of the device, however, is a significant challenge that causes the experimental value of the power conversion efficiency to deviate from the theoretical value. In this work, we explore a promising strategy using CdSe quantum dots (QDs) to enhance the photocurrent of the limited subcell to match with those of the other subcells and to enhance the power conversion efficiency of InGaP/GaAs/Ge tandem solar cells. The underlying mechanism of the enhancement can be attributed to the QD's unique capacity for photon conversion that tailors the incident spectrum of solar light; the enhanced efficiency of the device is therefore strongly dependent on the QD's dimensions. As a result, by appropriately selecting and spreading 7 mg/mL of CdSe QDs with diameters of 4.2 nm upon the InGaP/GaAs/Ge solar cell, the power conversion efficiency shows an enhancement of 10.39% compared to the cell's counterpart without integrating CdSe QDs. PMID:24514936

  15. Identification of nuclear factor kappaB (NF-?B) binding motifs in Biomphalaria glabrata.

    PubMed

    Humphries, Judith; Harter, Briana

    2015-12-01

    Biomphalaria glabrata acts as the intermediate host to the parasite, Schistosoma mansoni, and for this reason, the immune system of B. glabrata has been researched extensively. Several studies have demonstrated that the transcriptome profile of B. glabrata changes following exposure to a variety of pathogens, yet very little is known regarding the regulation of gene expression in this species. Nuclear factor kappaB (NF-?B) homologues have recently been identified in B. glabrata but few functional studies have been carried out on this family of transcription factors. The aims of this study therefore were to identify NF-?B binding sites (?B motifs) in B. glabrata and examine them via functional assays. Two different ?B motifs were predicted. Furthermore, the Rel homology domain (RHD) of a B. glabrata NF-?B was able to bind these ?B motifs in EMSAs, as well as a vertebrate ?B motif. PMID:26277107

  16. Enhanced fill factor of tandem organic solar cells incorporating a diketopyrrolopyrrole-based low-bandgap polymer and optimized interlayer.

    PubMed

    Wang, Dong Hwan; Kyaw, Aung Ko Ko; Park, Jong Hyeok

    2015-01-01

    We demonstrate that reproducible results can be obtained from tandem solar cells based on the wide-bandgap poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2',1',3'-benzothiadiazole] (PCDTBT) and the diketopyrrolopyrrole (DPP)-based narrow bandgap polymer (DT-PDPP2T-TT) with a decyltetradecyl (DT) and an electron-rich 2,5-di-2-thienylthieno[3,2-b]thiophene (2T-TT) group fabricated using an optimized interlayer (ZnO NPs/ph-n-PEDOT:PSS) [NPs: nanoparticles; ph-n: pH-neutral PEDOT: poly(3,4-ethylenedioxythiophene); PSS: polystyrene sulfonate]. The tandem cells are fabricated by applying a simple process without thermal annealing. The ZnO NP interlayer operates well when the ZnO NPs are dispersed in 2-methoxyethanol, as no precipitation and chemical reactions occur. In addition to the ZnO NP film, we used neutral PEDOT:PSS as a second interlayer which is not affect to the sequential deposited bulk heterojunction (BHJ) active layer of acidification. The power conversion efficiency (PCE) of a tandem device reaches 7.4?% (open-circuit voltage VOC =1.53?V, short-circuit current density JSC =7.3?mA?cm(-2) , and fill factor FF=67?%). Furthermore, FF is increased to up to 71?% when another promising large bandgap (bandgap ?1.94?eV) polymer (PBnDT-FTAZ) is used. The surface of each layer with nanoscale morphology (BHJ1/ZnO NPs film/ph-n-PEDOT:PSS/BHJ2) was examined by means of AFM analysis during sequential processing. The combination of these factors, efficient DPP-based narrow bandgap material and optimized interlayer, leads to the high FF (average approaches 70?%) and reproducibly operating tandem BHJ solar cells. PMID:25404201

  17. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry.

    PubMed

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2015-07-01

    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method. PMID:25882424

  18. Repression of transforming-growth-factor-beta-mediated transcription by nuclear factor kappaB.

    PubMed Central

    Nagarajan, R P; Chen, F; Li, W; Vig, E; Harrington, M A; Nakshatri, H; Chen, Y

    2000-01-01

    Activation of transforming growth factor-beta (TGF-beta) and activin receptors leads to phosphorylation of Sma- and Mad-related protein 2 (Smad2) and Smad3, which function as transcription factors to regulate gene expression. Smad7 is a regulatory protein which is able to inhibit TGF-beta and activin signalling in a negative-feedback loop, mediated by a direct regulation by Smad3 and Smad4 via a Smad-binding element (SBE) in the Smad7 promoter. Interestingly, we found that the Smad7 promoter was also regulated by nuclear factor kappaB (NF-kappaB), a transcription factor which plays an important role in inflammation and the immune response. Expression of NF-kappaB p65 subunit was able to inhibit the Smad7 promoter activity, and this inhibition could be reversed by co-expression of IkappaB, an inhibitor of NF-kappaB. In addition, the inhibitory activity of p65 was observed in a minimal promoter that contained only the Smad7 SBE and a TATA box, without any consensus NF-kappaB binding site. This inhibitory effect appeared to be common to other TGF-beta- and activin-responsive promoters, since p65 also inhibited the forkhead-activin-signal-transducer-2-mediated activation of a Xenopus Mix.2 promoter, as well as the Smad3-mediated activation of 3TP-lux which contains PMA-responsive elements and a plasminogen-activator-inhibitor-1 promoter. Activation of endogenous NF-kappaB by tumour necrosis factor-alpha (TNF-alpha) was also able to inhibit the Smad7 promoter in human embryonic kidney 293 cells. In human hepatoma HepG2 cells, TNF-alpha was able to inhibit TGF-beta- and activin-mediated transcriptional activation. Furthermore, overexpression of the transcription co-activator p300 could abrogate the inhibitory effect of NF-kappaB on the Smad7 promoter. Taken together, these data have indicated a novel mode of crosstalk between the Smad and the NF-kappaB signalling cascades at the transcriptional level by competing for a limiting pool of transcription co-activators. PMID:10839991

  19. Tandem betatron

    DOEpatents

    Keinigs, Rhonald K. (Santa Fe, NM)

    1992-01-01

    Two betatrons are provided in tandem for alternately accelerating an electron beam to avoid the single flux swing limitation of conventional betatrons and to accelerate the electron beam to high energies. The electron beam is accelerated in a first betatron during a period of increasing magnetic flux. The eletron beam is extracted from the first betatron as a peak magnetic flux is reached and then injected into a second betatron at a time of minimum magnetic flux in the second betatron. The cycle may be repeated until the desired electron beam energy is obtained. In one embodiment, the second betatron is axially offset from the first betatron to provide for electron beam injection directly at the axial location of the beam orbit in the second betatron.

  20. A tandem sequence motif acts as a distance-dependent enhancer in a set of genes involved in translation by binding the proteins NonO and SFPQ

    PubMed Central

    2011-01-01

    Background Bioinformatic analyses of expression control sequences in promoters of co-expressed or functionally related genes enable the discovery of common regulatory sequence motifs that might be involved in co-ordinated gene expression. By studying promoter sequences of the human ribosomal protein genes we recently identified a novel highly specific Localized Tandem Sequence Motif (LTSM). In this work we sought to identify additional genes and LTSM-binding proteins to elucidate potential regulatory mechanisms. Results Genome-wide analyses allowed finding a considerable number of additional LTSM-positive genes, the products of which are involved in translation, among them, translation initiation and elongation factors, and 5S rRNA. Electromobility shift assays then showed specific signals demonstrating the binding of protein complexes to LTSM in ribosomal protein gene promoters. Pull-down assays with LTSM-containing oligonucleotides and subsequent mass spectrometric analysis identified the related multifunctional nucleotide binding proteins NonO and SFPQ in the binding complex. Functional characterization then revealed that LTSM enhances the transcriptional activity of the promoters in dependency of the distance from the transcription start site. Conclusions Our data demonstrate the power of bioinformatic analyses for the identification of biologically relevant sequence motifs. LTSM and the here found LTSM-binding proteins NonO and SFPQ were discovered through a synergistic combination of bioinformatic and biochemical methods and are regulators of the expression of a set of genes of the translational apparatus in a distance-dependent manner. PMID:22185324

  1. Emodin has cytotoxic and protective effects in rat C6 glioma cells: roles of Mdr1a and nuclear factor kappaB in cell survival.

    PubMed

    Kuo, Tzu-Ching; Yang, Jai-Sing; Lin, Meng-Wei; Hsu, Shu-Chun; Lin, Jen-Jyh; Lin, Hui-Ju; Hsia, Te-Chun; Liao, Ching-Lung; Yang, Mei-Due; Fan, Ming-Jen; Wood, W G; Chung, Jing-Gung

    2009-09-01

    1,3,8-Trihydroxy-6-methylanthaquinone (emodin) is recognized as an antiproliferative compound. In the present study, however, we show that emodin has both toxic and survival effects in glioma cells and that the survival effects involve Mdr1a. Emodin inhibited the proliferation and induced apoptosis of C6 cells in a 12-h treatment, but C6 cells survived a 72-h drug treatment, indicating resistance to emodin. Emodin-induced apoptosis was reduced by inhibition of the expression and activation of apoptosis-associated proteins including p53, Bax, Bcl-2, Fas, and caspase-3. C6 cells could express antioxidant proteins (superoxide dismutase and catalase) to decrease reactive oxygen species-induced cytotoxicity of emodin and overexpress multidrug resistance genes (Mdr1a, MRP2, MRP3, and MRP6) to decrease the intracellular accumulation of emodin. Electrophoretic mobility shift analysis showed that emodin decreased nuclear factor kappaB (NF-kappaB) expression in 24 h of treatment, but in 48 h, emodin increased NF-kappaB activity. A confocal microscope showed that emodin induced NF-kappaB translocation from cytoplasm to nuclei. C6 cells would activate the mitogen-activated protein kinase survival pathway and express the DNA repair gene (MGMT) and associated proteins (PARP and XRCC1) to recover the cell activity. C6 cells also expressed GRP78 to decrease emodin-induced endoplasmic reticulum (ER) stress that would cause apoptosis in C6 cells, and GRP78 inhibited the expression of GADD153 to enhance the expression of Bcl-2 that could balance the ER- and mitochondria-induced apoptosis of C6 cells. PMID:19549930

  2. Enhanced SDC-assisted digestion coupled with lipid chromatography-tandem mass spectrometry for shotgun analysis of membrane proteome.

    PubMed

    Lin, Yong; Wang, Kunbo; Liu, Zhonghua; Lin, Haiyan; Yu, Lijun

    2015-10-01

    Despite the biological importance of membrane proteins, their analysis has lagged behind that of soluble proteins and still presents a great challenge mainly because of their highly hydrophobic nature and low abundance. Sodium deoxycholate (SDC)-assisted digestion strategy has been introduced in our previous papers, which cleverly circumvents many of the challenges in shotgun membrane proteomics. However, it is associated with significant sample loss due to the slightly weaker extraction/solubilization ability of 1% SDC. In this study, an enhanced SDC-assisted digestion method (ESDC method) was developed that incorporates the almost strongest ability of SDC with a high concentration (5%) to lyse membrane and extract/solubilize hydrophobic membrane proteins, and then dilution to 1% for more efficient digestion. The comparative study using rat liver membrane-enriched sample showed that, compared with previous SDC-assisted method and the "universal" filter-aided sample preparation (FASP) method, the ESDC method not only increased the identified number of total proteins, membrane proteins, hydrophobic proteins, integral membrane proteins (IMPs) and IMPs with more than 5 transmembrane domains (TMDs) by an average of 10.8%, 13.2%, 17.8%, 17.9% and 52.9%, respectively, but also enhanced the identified number of total peptides and hydrophobic peptides by averagely 12.5% and 14.2%. These results demonstrated that the ESDC method provides a substantial improvement in the recovery and identification of membrane proteins, especially those with high hydrophobicity and multiple TMDs, and thereby displaying more potential for shotgun membrane proteomics. PMID:26319803

  3. 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

  4. Enhanced Methamphetamine Metabolism in Rhesus Macaque as Compared with Human: An Analysis Using a Novel Method of Liquid Chromatography with Tandem Mass Spectrometry, Kinetic Study, and Substrate Docking

    PubMed Central

    Wang, Lei; Bosinger, Steven; Li, Junhao; Shah, Ankit; Gangwani, Mohitkumar; Nookala, Anantha; Liu, Xun; Cao, Lu; Jackson, Austin; Silverstein, Peter S.; Fox, Howard S.; Li, Weihua; Kumar, Anil

    2014-01-01

    Methamphetamine (MA), which remains one of the widely used drugs of abuse, is metabolized by the cytochrome P450 (P450) family of enzymes in humans. However, metabolism of methamphetamine in macaques is poorly understood. Therefore, we first developed and validated a very sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) method using solid phase extraction of rhesus plasma with a lower limit of quantitation at 1.09 ng/ml for MA and its metabolites, 4-hydroxy methamphetamine (4-OH MA), amphetamine (AM), 4-OH amphetamine (4-OH AM), and norephedrine. We then analyzed plasma samples of MA-treated rhesus, which showed >10-fold higher concentrations of AM (?29 ng/ml) and 4-OH AM (?28 ng/ml) than MA (?2 ng/ml). Because the plasma levels of MA metabolites in rhesus were much higher than in human samples, we examined MA metabolism in human and rhesus microsomes. Interestingly, the results showed that AM and 4-OH AM were formed more rapidly and that the catalytic efficiency (Vmax/Km) for the formation of AM was ?8-fold higher in rhesus than in human microsomes. We further examined the differences in these kinetic characteristics using three selective inhibitors of each human CYP2D6 and CYP3A4 enzymes. The results showed that each of these inhibitors inhibited both d- and l-MA metabolism by 20%–60% in human microsomes but not in rhesus microsomes. The differences between human and rhesus CYP2D6 and CYP3A4 enzymes were further assessed by docking studies for both d and l-MA. In conclusion, our results demonstrated an enhanced MA metabolism in rhesus compared with humans, which is likely to be caused by differences in MA-metabolizing P450 enzymes between these species. PMID:25301936

  5. Roxithromycin inhibits nuclear factor kappaB signaling and endoplasmic reticulum stress in intestinal epithelial cells and ameliorates experimental colitis in mice.

    PubMed

    Choi, Younjeong; Koh, Seong-Joon; Lee, Hee Sook; Kim, Ji Won; Gwan Kim, Byeong; Lee, Kook Lae; Kim, Joo Sung

    2015-12-01

    Roxithromycin is known to have anti-inflammatory and immunoregulatory activity. However, little information is available on the effect of roxithromycin in intestinal inflammation. The aim of this study was to investigate the effect of roxithromycin on NF- ?B signaling and ER stress in intestinal epithelial cells (IECs) and the effect of roxithromycin on dextran sulfate sodium (DSS)-induced acute colitis in a murine model. HCT116 cells and COLO205 cells were pretreated with roxithromycin and then stimulated with tumor necrosis factor-? (TNF-?). Interleukin (IL)-8 expression was determined by real-time reverse transcription-polymerase chain reaction. Nuclear factor kappaB (NF-?B) DNA-binding activity and I?B phosphorylation/degradation were evaluated by electrophoretic mobility shift assay and Western blot analysis. The molecular markers of endoplasmic reticulum stress, including p-JNK, phosphorylated eukaryotic initiation factor 2 (p-eIF2?), C/EBP homologous protein (CHOP), and X-box binding protein 1 (XBP1) were evaluated using western blotting and PCR. Mice were given 4% DSS for five days with or without roxithromycin. Primary IECs were isolated from mice with DSS-induced colitis. Roxithromycin significantly inhibited the upregulated expression of IL-8. Pretreatment with roxithromycin markedly attenuated NF-?B DNA-binding activity and I?B phosphorylation/degradation. CHOP and XBP1 mRNA expression were enhanced in the presence of TNF-?, and it was dampened by pretreatment of roxithromycin. c-Jun-N-terminal kinase (JNK) phosphorylation and the level of p-eIF2? were also downregulated by the pretreatment of roxithromycin. Roxithromycin significantly reduced the severity of DSS-induced murine colitis, as assessed by the disease activity index, colon length, and histology. In addition, the DSS-induced phospho-I?B kinase activation was significantly decreased in roxithromycin-pretreated mice. Finally, I?B degradation was reduced in primary IECs from mice treated with roxithromycin. These results suggest that roxithromycin may have potential usefulness in the treatment of inflammatory bowel disease. PMID:26088864

  6. Involvement of diacylglycerol production in activation of nuclear factor kappaB by a CD14-mediated lipopolysaccharide stimulus.

    PubMed Central

    Yamamoto, H; Hanada, K; Nishijima, M

    1997-01-01

    Exposure of Chinese hamster CHO-K1 transfectant cells expressing mouse CD14 (CHO/CD14 cells) to lipopolysaccharide (LPS) induced rapid elevation of the cellular diacylglycerol (DAG) and choline/phosphocholine levels and nuclear translocation of nuclear factor kappaB (NFkappaB). When cells were incubated with short-chain DAG analogues or bacterial phospholipase C, NFkappaB activation occurred even without the LPS stimulus. Treatment of CHO/CD14 cells with tricyclo[5.2.1.0(2.6)]decyl-(9[8])xanthogenate (D609), an inhibitor of phosphatidylcholine-specific phospholipase C and phospholipase D, almost completely inhibited not only the LPS-dependent production of DAG and choline/phosphocholine but also the LPS-dependent NFkappaB activation. In contrast, treatment of cells with 1-(6-¿[3-methoxyoestra-1,3, 5(10)-trien-17beta-yl]-1H-pyrrole-2,5-dione (U73122), an inhibitor of phosphatidylinositol-specific phospholipase C in vitro, did not affect the LPS-dependent activation of NFkappaB. Production of DAG and activation of NFkappaB after the LPS stimulus were observed in mouse macrophage-like J774.1 cells, and this response to LPS by J774. 1 cells was also inhibited by D609. These results suggest that the production of DAG from phosphatidylcholine was upstream of NFkappaB activation in response to a CD14-mediated LPS stimulus. PMID:9224650

  7. Nuphar lutea thioalkaloids inhibit the nuclear factor kappaB pathway, potentiate apoptosis and are synergistic with cisplatin and etoposide.

    PubMed

    Ozer, Janet; Eisner, Nadav; Ostrozhenkova, Elena; Bacher, Adelbert; Eisenreich, Wolfgang; Benharroch, Daniel; Golan-Goldhirsh, Avi; Gopas, Jacob

    2009-10-01

    We screened thirty-four methanolic plant extracts for inhibition of the constitutive nuclear factor kappaB (NFkappaB) activity by a NFkappaB-luciferase reporter gene assay. Strong inhibition of NFkappaB activity was found in extracts of leaf and rhizome from Nuphar lutea L. SM. (Nuphar). The inhibitory action was narrowed down to a mixture of thionupharidines and/or thionuphlutidines that were identified in chromatography fractions by one- and two-dimensional NMR analysis. Dimeric sesquiterpene thioalkaloids were identified as the major components of the mixture. The Nuphar alkaloids mixture (NUP) showed a dose dependent inhibition of NFkappaB activity in a luciferase reporter gene assay as well as reduction of nuclear NFkappaB subunits expression as tested by western blots and immunohistochemistry. Decreased DNA binding was demonstrated in electro mobility shift assays. NUP inhibited both inducible and constitutive NFkappaB activation and affected the canonical and alternative pathways. Suppression of NFkappaB was not cell type specific. Induction of apoptosis by the alkaloid mixture was demonstrated by time-dependent and dose-dependent cleavage of procaspase-9 and PARP. Synergistic cytotoxicity of the active mixture with cisplatin and etoposide was demonstrated. Overall, our results show that NUP inhibits the NFkappaB pathway and acts as a sensitizer to conventional chemotherapy, enabling the search for its specific target and application against cancer and inflammation. PMID:19713755

  8. Efficient enhancement of hydrogen production by Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrochemical cell

    SciTech Connect

    Liu, Ying; Ren, Feng Chen, Chao; Liu, Chang; Xing, Zhuo; Liu, Dan; Xiao, Xiangheng; Wu, Wei; Zheng, Xudong; Liu, Yichao; Jiang, Changzhong; Shen, Shaohua; Fu, Yanming

    2015-03-23

    Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu{sub 2}O/ZnO photoelectrode comparing to that of the Cu{sub 2}O film. The high performance of the Ag/Cu{sub 2}O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode.

  9. Thermal-barrier production and indentification in a tandem mirror

    SciTech Connect

    Grubb, D.P.; Allen, S.L.; Casper, T.A.; Clauser, J.F.; Coensgen, F.H.; Correll, D.L.; Cummins, W.F.; Damm, C.C.; Foote, J.H.; Goodman, R.K.; Hill, D.N.; Hooper,Jr., E.B.; Hornady, R.S.; Hunt, A.L.; Kerr, R.G.; Leppelmeier, G.W.; Marilleau, J.; Moller, J.M.; Molvik, A.W.; Nexsen, W.E.; Pickles, W.L.; Porter, G.D.; Poulsen, P.; Silver, E.H.; Simonen, T.C.; Stallard, B.W.; Turner, W.C.; Hsu, W.L.; Yu, T.L.; Barter, J.D.; Christensen, T.; Dimonte, G.; Romesser, T.W.; Ellis, R.F.; James, R.A.; Lasnier, C.J.; Berzins, L.V.; Carter, M.R.; Clower, C.A.; Failor, B.H.; Falabella, S.; Flammer, M.; Nash, T.

    1984-08-20

    In thermal-barrier experiments in the tandem mirror experiment upgrade axial confinement times of 50 to 100 ms have been achieved. During enhanced confinement we measured the thermal-barrier potential profile using a neutral-particle-beam probe. The experimental data agree qualitatively and quantitatively with the theory of thermal-barrier formation in a tandem mirror.

  10. Tandem mobile robot system

    SciTech Connect

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  11. Mutagenesis of 8-oxoguanine adjacent to an abasic site in simian kidney cells: tandem mutations and enhancement of G-->T transversions.

    PubMed

    Kalam, M Abul; Basu, Ashis K

    2005-08-01

    Clustered DNA damages are well-established characteristics of ionizing radiation. As a model clustered lesion in the same strand of DNA, we have evaluated the mutagenic potential of 8-oxoguanine (8-oxoG) adjacent to a uracil in simian kidney cells using a phagemid vector. The uracil residue would be excised by the enzyme uracil DNA glycosylase in vivo generating an abasic site (AP site). A solitary uracil in either GUGTC or GTGUC sequence context provided >60% progeny containing GTGTC indicating that dAMP incorporation opposite the AP site or uracil occurred, but a >30% population showed replacement of U by A, C, or G, which suggests that dTMP, dGMP, or dCMP incorporation also occurred, respectively, opposite the AP site. While the preference for targeted base substitutions at the GUG site was T > C > A > G, the same at the GUC site was T > A > C > G. We conclude that base incorporation opposite an AP site is sequence-dependent. For 8-oxoG, as compared to 23-24% G-->T mutants from a single 8-oxoG in a TG(8-oxo)T sequence context, the tandem lesions UG(8-oxo)T and TG(8-oxo)U generated approximately 60 and >85% progeny, respectively, that did not contain the TGT sequence. A significant fraction of tandem mutations were detected when uracil was adjacent to 8-oxoG. What we found most interesting is that the total targeted G(8-oxo)-->T transversions that included both single and tandem mutations at the TG(8-oxo)U site was nearly 60% relative to about 30% at the UG(8-oxo)T site. A higher mutational frequency at the TG(8-oxo)U sequence may arise from a change in DNA polymerase that is more error prone. Thermal melting experiments showed that the Tm for the 8-oxoG:C pair in the TG(8-oxo)(AP*) sequence in a 12-mer was lower than the same in a (AP*)G(8-oxo)T 12-mer with deltadeltaG 0.8 kcal/mol (where AP* represents tetrahydrofuran, the model abasic site). When the 8-oxoG:C pair in each sequence was compared with a 8-oxoG:A pair, the former was found to be more stable than the latter. The preference for C over A opposite 8-oxoG for the (AP*)G(8-oxo)T 12-mer duplex with a deltadeltaG of 1.6 kcal/mol dropped to 0.4 kcal/mol in the TG(8-oxo)(AP*) 12-mer duplex. This suggests that the polymerase discrimination to incorporate dCMP over dAMP would be less efficient in the TG(8-oxo)(AP*) sequence relative to (AP*)G(8-oxo)T. Additionally, the efficiency of recognition and excision of A opposite 8-oxoG by a mismatch repair protein may be impaired in the TG(8-oxo)(AP*) sequence context. PMID:16097791

  12. Tandem mirror fusion research

    SciTech Connect

    Baldwin, D.E.

    1983-12-02

    The tandem mirror program has evolved considerably in the last decade. Of significance is the viable reactor concept embodied in the MARS design. An aggressive experimental program, culminating in the operation of MFTF-B in late 1986, will provide a firm basis for refining the MARS design as necessary for constructing a reactor prototype in the 1990s.

  13. Organic Tandem Solar Cells: Design and Formation

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chao

    In the past decade, research on organic solar cells has gone through an important development stage leading to major enhancements in power conversion efficiency, from 4% to 9% in single-junction devices. During this period, there are many novel processing techniques and device designs that have been proposed and adapted in organic solar-cell devices. One well-known device architecture that helps maximize the solar cell efficiency is the multi-junction tandem solar-cell design. Given this design, multiple photoactive absorbers as subcells are stacked in a monolithic fashion and assembled via series connection into one complete device, known as the tandem solar cell. Since multiple absorbers with different optical energy bandgaps are being applied in one tandem solar-cell device, the corresponding solar cell efficiency is maximized through expanded absorption spectrum and reduced carrier thermalization loss. In Chapter 3, the architecture of solution-processible, visibly transparent solar cells is introduced. Unlike conventional organic solar-cell devices with opaque electrodes (such as silver, aluminum, gold and etc.), the semi-transparent solar cells rely on highly transparent electrodes and visibly transparent photoactive absorbers. Given these two criteria, we first demonstrated the visibly transparent single-junction solar cells via the polymer absorber with near-infrared absorption and the top electrode based on solution-processible silver nanowire conductor. The highest visible transparency (400 ˜ 700 nm) of 65% was achieved for the complete device structure. More importantly, power conversion efficiency of 4% was also demonstrated. In Chapter 4, we stacked two semi-transparent photoactive absorbers in the tandem architecture in order to realize the semi-transparent tandem solar cells. A noticeable performance improvement from 4% to 7% was observed. More importantly, we modified the interconnecting layers with the incorporation of a thin conjugated polyelectrolyte layer functioning as the surface dipole formation layer to provide better electrical contact with the photoactive layer. Due to the effectiveness of the conjugated polyelectrolyte layer, performance improvement was also observed. Furthermore, other issues regarding the semi-transparent tandem solar cells (e.g., photocurrent matching, exterior color tuning, and transparency tuning) are all explored to optimize best performance. In Chapter 5 and 6, the architectures of double- and triple-junction tandem solar cells are explored. Theoretically, triple-junction tandem solar cells with three photoactive absorbers with cascaded energy bandgaps have the potential to achieve higher performance, in comparison with double-junction tandem solar cells. Such expectations can be ascribed to the minimized carrier thermalization loss and further improved light absorption. However, the design of triple-junction solar cells often involves sophisticated multiple layer deposition as well as substantial optimization. Therefore, there is a lack of successful demonstrations of triple-junction solar cells outperforming the double-junction counterparts. To solve the incompatible issues related to the layer deposition in the fabrication, we proposed a novel architecture of inverted-structure tandem solar cells with newly designed interconnecting layers. Our design of interconnecting layers does not only focus on maintaining the orthogonal solution processing advantages, but also provides an excellent compatibility in the energy level alignment to allow different absorber materials to be used. Furthermore, we also explored the light management inside the double- and triple-junction tandem solar cells. The study of light management was carried out through optical simulation method based transfer matrix formalism. The intention is to obtain a balanced photocurrent output from each subcells inside the tandem solar cell, thus the minimal recombination loss at the contact of interconnecting layers and the optimal efficiency can be expected. With help from simulations, we were able to ca

  14. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, Ian J. (Albuquerque, NM); Wendt, Joel R. (Albuquerque, NM)

    1994-01-01

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors.

  15. Transcription factor Spi-B binds unique sequences present in the tandem repeat promoter/enhancer of JC virus and supports viral activity

    PubMed Central

    Marshall, Leslie J.; Dunham, Lisa; Major, Eugene O.

    2010-01-01

    Progressive multifocal leukoencephalopathy (PML) is an often fatal demyelinating disease caused by lytic infection of oligodendrocytes with JC virus (JCV). The development of PML in non-immunosuppressed individuals is a growing concern with reports of mortality in patients treated with mAb therapies. JCV can persist in the kidneys, lymphoid tissue and bone marrow. JCV gene expression is restricted by non-coding viral regulatory region sequence variation and cellular transcription factors. Because JCV latency has been associated with cells undergoing haematopoietic development, transcription factors previously reported as lymphoid specific may regulate JCV gene expression. This study demonstrates that one such transcription factor, Spi-B, binds to sequences present in the JCV promoter/enhancer and may affect early virus gene expression in cells obtained from human brain tissue. We identified four potential Spi-B-binding sites present in the promoter/enhancer elements of JCV sequences from PML variants and the non-pathogenic archetype. Spi-B sites present in the promoter/enhancers of PML variants alone bound protein expressed in JCV susceptible brain and lymphoid-derived cell lines by electromobility shift assays. Expression of exogenous Spi-B in semi- and non-permissive cells increased early viral gene expression. Strikingly, mutation of the Spi-B core in a binding site unique to the Mad-4 variant was sufficient to abrogate viral activity in progenitor-derived astrocytes. These results suggest that Spi-B could regulate JCV gene expression in susceptible cells, and may play an important role in JCV activity in the immune and nervous systems. PMID:20826618

  16. Current results of the tandem mirror experiment

    SciTech Connect

    Drake, R.P.

    1980-04-09

    The basic operating characteristics of the Tandem Mirror Experiment, (TMX) at the Lawrence Livermore Laboratory in the USA have been established. Tandem-mirror plasmas have been produced using neutral-beam-fueled end plugs and a gas-fueled center cell. An axial potential well between the end plugs has been measured. There is direct evidence that this potential well enhances the axial confinement of the center-cell ions. The observed densities and loss currents are consistent with preliminary studies of the particle sources and losses near the magnetic axis. The observed confinement is consistent with theory when plasma fluctuations are low. When the requirement of drift-cyclotron loss-cone mode stability is violated, the plasma fluctuations degrade the center-cell confinement.

  17. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W. (Golden, CO)

    1994-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

  18. Monolithic tandem solar cell

    DOEpatents

    Wanlass, M.W.

    1994-06-21

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. 9 figs.

  19. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W. (Golden, CO)

    1991-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

  20. Tandems as injectors for synchrotrons

    SciTech Connect

    Ruggiero, A.G.

    1992-01-01

    This is a review on the use of Tandem electrostatic accelerators for injection and filling of synchrotrons to accelerate intense beams of heavy-ions to relativistic energies. The paper emphasizes the need of operating the Tandems in pulsed mode for this application. It has been experimentally demonstrated that at the present this type of accelerators still provides the most reliable and best performance.

  1. Tandems as injectors for synchrotrons

    SciTech Connect

    Ruggiero, A.G.

    1992-08-01

    This is a review on the use of Tandem electrostatic accelerators for injection and filling of synchrotrons to accelerate intense beams of heavy-ions to relativistic energies. The paper emphasizes the need of operating the Tandems in pulsed mode for this application. It has been experimentally demonstrated that at the present this type of accelerators still provides the most reliable and best performance.

  2. Nuclear factor {kappa}B (NF{kappa}B) and cyclooxygenase-2 (Cox-2) expression in the irradiated colorectum is associated with subsequent histopathological changes

    SciTech Connect

    Yeoh, Ann S.J. . E-mail: ann.yeoh@imvs.sa.gov.au; Bowen, Joanne M.; Gibson, Rachel J.; Keefe, Dorothy M.K.

    2005-12-01

    Purpose: Recent studies have proposed that mucositis development is the same throughout the gastrointestinal tract (GIT), as it is formed from one structure embryologically. Radiation-induced oral mucositis studies have outlined the key involvement of nuclear factor {kappa}B (NF{kappa}B) and cyclooxygenase-2 (Cox-2) in its pathobiology. The purpose of this study was therefore to investigate the expression of NF{kappa}B and Cox-2 in the irradiated colorectum and to correlate these with the associated histopathologic changes. Methods and Materials: Colorectal tissues from 28 colorectal cancer patients treated with preoperative radiotherapy were analyzed for histopathologic changes using a variety of tissue staining methods. The expression of NF{kappa}B and Cox-2 in these tissues was investigated using immunohistochemistry. Changes in expression of these proteins were then correlated with the histopathologic changes. Results: Radiation therapy caused injury to the normal colorectal tissue surrounding tumor site, particularly around the blood vessels. These changes were reflected in changes in NF{kappa}B and Cox-2 expression. Conclusions: We conclude that different regions of the GIT, the colorectum, and oral cavity have similar underlying mechanisms of radiation-induced mucositis. Understanding these mechanisms will allow new approaches to be developed to specifically target steps in the evolution of alimentary mucositis.

  3. Isoliquiritigenin Inhibits Metastatic Breast Cancer Cell-induced Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin Ratio in Human Osteoblastic Cells

    PubMed Central

    Lee, Sun Kyoung; Park, Kwang-Kyun; Kim, Ki Rim; Kim, Hyun-Jeong; Chung, Won-Yoon

    2015-01-01

    Bone destruction induced by the metastasis of breast cancer cells is a frequent complication that is caused by the interaction between cancer cells and bone cells. Receptor activator of nuclear factor kappa-B ligand (RANKL) and the endogenous soluble RANKL inhibitor, osteoprotegerin (OPG), directly play critical roles in the differentiation, activity, and survival of osteoclasts. In patients with bone metastases, osteoclastic bone resorption promotes the majority of skeletal-related events and propagates bone metastases. Therefore, blocking osteoclast activity and differentiation via RANKL inhibition can be a promising therapeutic approach for cancer-associated bone diseases. We investigated the potential of isoliquiritigenin (ISL), which has anti-proliferative, anti-angiogenic, and anti-invasive effects, as a preventive and therapeutic agent for breast cancer cell-induced bone destruction. ISL at non-toxicity concentrations significantly inhibited the RANKL/OPG ratio by reducing the production of RANKL and restoring OPG production to control levels in hFOB1.19 cells stimulated with conditioned medium (CM) of MDA-MB-231 cells. In addition, ISL reduced the expression of cyclooxygenase-2 in hFOB1.19 cells stimulated by CM of MDA-MB-231 cells. Therefore, ISL may have inhibitory potential on breast cancer-induced bone destruction.

  4. Fueling of tandem mirror reactors

    SciTech Connect

    Gorker, G.E.; Logan, B.G.

    1985-01-01

    This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed for the Tandem Mirror Reactor Systems Code (TMRSC) to select the pellet injector/accelerator combination which most nearly satisfies the fueling requirements for a given machine design.

  5. Collective Flow Enhancement by Tandem Flapping Wings

    NASA Astrophysics Data System (ADS)

    Gravish, Nick; Peters, Jacob M.; Combes, Stacey A.; Wood, Robert J.

    2015-10-01

    We examine the fluid-mechanical interactions that occur between arrays of flapping wings when operating in close proximity at a moderate Reynolds number (Re ?100 - 1000 ). Pairs of flapping wings are oscillated sinusoidally at frequency f , amplitude ?M, phase offset ? , and wing separation distance D*, and outflow speed v* is measured. At a fixed separation distance, v* is sensitive to both f and ? , and we observe both constructive and destructive interference in airspeed. v* is maximized at an optimum phase offset, ?max, which varies with wing separation distance, D*. We propose a model of collective flow interactions between flapping wings based on vortex advection, which reproduces our experimental data.

  6. Osteopontin is associated with nuclear factor {kappa}B gene expression during tail-suspension-induced bone loss

    SciTech Connect

    Ishijima, Muneaki; Ezura, Yoichi . E-mail: ezura.mph@mril.tmd.ac.jp; Tsuji, Kunikazu

    2006-10-01

    Osteoporosis due to unloading-induced bone loss is a critical issue in the modern aging society. Although the mechanisms underlying this phenomenon are largely unknown, osteopontin (OPN) is one of the critical mediators required for unloading-induced bone loss [M. Ishijima, S.R. Rittling, T. Yamashita, K. Tsuji, H. Kurosawa, A. Nifuji, D.T. Denhardt, and M. Noda, Enhancement of osteoclastic bone resorption and suppression of osteoblastic bone formation in response to reduced mechanical stress do not occur in the absence of osteopontin, J Exp Med, 193 (2001) 399-404]. To clarify the molecular bases for OPN actions, we carried out microarray analyses on the genes expressed in the femoral bone marrow cells in wild type and OPN-/- mice. The removal of the mechanical load induced bone loss in wild type, but not in OPN-/- mice, as previously reported. Expression analysis of 9586 cDNAs on a microarray system revealed that OPN deficiency blocked tail-suspension-induced expression of ten genes (group A). This observation was confirmed based on semi-quantitative RT-PCR analyses. On the other hand, expression of four genes (group B) was not altered by tail suspension in wild type but was enhanced in OPN-deficient mice. NF-{kappa}B p105 subunit gene (Nfkb1) was found in group A and Bax in group B. p53 gene expression was upregulated by tail suspension in wild type mice, but it was no longer observed in OPN-/- mice. These data indicate that OPN acts to mediate mechanical stress signaling upstream to the genes encoding apoptosis-related molecules, and its action is associated with alteration of the genes.

  7. Ten tandem repeats of {beta}-hCG 109-118 enhance immunogenicity and anti-tumor effects of {beta}-hCG C-terminal peptide carried by mycobacterial heat-shock protein HSP65

    SciTech Connect

    Zhang Yankai; Yan Rong; He Yi; Liu Wentao; Cao Rongyue; Yan Ming; Li Taiming; Liu Jingjing; Wu Jie . E-mail: wu_jie97@yahoo.com.cn

    2006-07-14

    The {beta}-subunit of human chorionic gonadotropin ({beta}-hCG) is secreted by many kinds of tumors and it has been used as an ideal target antigen to develop vaccines against tumors. In view of the low immunogenicity of this self-peptide,we designed a method based on isocaudamer technique to repeat tandemly the 10-residue sequence X of {beta}-hCG (109-118), then 10 tandemly repeated copies of the 10-residue sequence combined with {beta}-hCG C-terminal 37 peptides were fused to mycobacterial heat-shock protein 65 to construct a fusion protein HSP65-X10-{beta}hCGCTP37 as an immunogen. In this study, we examined the effect of the tandem repeats of this 10-residue sequence in eliciting an immune by comparing the immunogenicity and anti-tumor effects of the two immunogens, HSP65-X10-{beta}hCGCTP37 and HSP65-{beta}hCGCTP37 (without the 10 tandem repeats). Immunization of mice with the fusion protein HSP65-X10-{beta}hCGCTP37 elicited much higher levels of specific anti-{beta}-hCG antibodies and more effectively inhibited the growth of Lewis lung carcinoma (LLC) in vivo than with HSP65-{beta}hCGCTP37, which should suggest that HSP65-X10-{beta}hCGCTP37 may be an effective protein vaccine for the treatment of {beta}-hCG-dependent tumors and multiple tandem repeats of a certain epitope are an efficient method to overcome the low immunogenicity of self-peptide antigens.

  8. Characterization of osteoprotegerin binding to glycosaminoglycans by surface plasmon resonance: Role in the interactions with receptor activator of nuclear factor {kappa}B ligand (RANKL) and RANK

    SciTech Connect

    Theoleyre, S.; Kwan Tat, S.; Vusio, P.; Blanchard, F.; Gallagher, J.; Ricard-Blum, S.; Fortun, Y.; Padrines, M.; Redini, F.; Heymann, D. . E-mail: dominique.heymann@univ-nantes.fr

    2006-08-25

    Osteoprotegerin (OPG) is a decoy receptor for receptor activator of nuclear factor {kappa}B ligand (RANKL), a key inducer of osteoclastogenesis via its receptor RANK. We previously showed that RANK, RANKL, and OPG are able to form a tertiary complex and that OPG must be also considered as a direct effector of osteoclast functions. As OPG contains a heparin-binding domain, the present study investigated the interactions between OPG and glycosaminoglycans (GAGs) by surface plasmon resonance and their involvement in the OPG functions. Kinetic data demonstrated that OPG binds to heparin with a high-affinity (K {sub D}: 0.28 nM) and that the pre-incubation of OPG with heparin inhibits in a dose-dependent manner the OPG binding to the complex RANK-RANKL. GAGs from different structure/origin (heparan sulfate, dermatan sulfate, and chondroitin sulfate) exert similar activity on OPG binding. The contribution of the sulfation pattern and the size of the oligosaccharide were determined in this inhibitory mechanism. The results demonstrated that sulfation is essential in the OPG-blocking function of GAGs since a totally desulfated heparin loses its capacity to bind and to block OPG binding to RANKL. Moreover, a decasaccharide is the minimal structure that totally inhibits the OPG binding to the complex RANK-RANKL. Western blot analysis performed in 293 cells surexpressing RANKL revealed that the pre-incubation of OPG with these GAGs strongly inhibits the OPG-induced decrease of membrane RANKL half-life. These data support an essential function of the related glycosaminoglycans heparin and heparan sulfate in the activity of the triad RANK-RANKL-OPG.

  9. Tandem Terminal Ion Source

    SciTech Connect

    2000-10-23

    OAK-B135 Tandem Terminal Ion Source. The terminal ion source (TIS) was used in several experiments during this reporting period, all for the {sup 7}Be({gamma}){sup 8}B experiment. Most of the runs used {sup 1}H{sup +} at terminal voltages from 0.3 MV to 1.5 MV. One of the runs used {sup 2}H{sup +} at terminal voltage of 1.4 MV. The other run used {sup 4}He{sup +} at a terminal voltage of 1.37 MV. The list of experiments run with the TIS to date is given in table 1 below. The tank was opened four times for unscheduled source repairs. On one occasion the tank was opened to replace the einzel lens power supply which had failed. The 10 kV unit was replaced with a 15 kV unit. The second time the tank was opened to repair the extractor supply which was damaged by a tank spark. On the next occasion the tank was opened to replace a source canal which had sputtered away. Finally, the tank was opened to replace the discharge bottle which had been coated with aluminum sputtered from the exit canal.

  10. Tandem Cylinder Noise Predictions

    NASA Technical Reports Server (NTRS)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to capture the complete decay in the spanwise correlation, thereby producing reasonable noise radiation levels.

  11. Tandem-structured, hot electron based photovoltaic cell with double Schottky barriers

    PubMed Central

    Lee, Young Keun; Lee, Hyosun; Park, Jeong Young

    2014-01-01

    We demonstrate a tandem-structured, hot electron based photovoltaic cell with double Schottky barriers. The tandem-structured, hot electron based photovoltaic cell is composed of two metal/semiconductor interfaces. Two types of tandem cells were fabricated using TiO2/Au/Si and TiO2/Au/TiO2, and photocurrent enhancement was detected. The double Schottky barriers lead to an additional pathway for harvesting hot electrons, which is enhanced through multiple reflections between the two barriers with different energy ranges. In addition, light absorption is improved by the band-to-band excitation of both semiconductors with different band gaps. Short-circuit current and energy conversion efficiency of the tandem-structured TiO2/Au/Si increased by 86% and 70%, respectively, compared with Au/Si metal/semiconductor nanodiodes, showing an overall solar energy conversion efficiency of 5.3%. PMID:24694838

  12. Polymer homo-tandem solar cells with best efficiency of 11.3%.

    PubMed

    Zhou, Huiqiong; Zhang, Yuan; Mai, Cheng-Kang; Collins, Samuel D; Bazan, Guillermo C; Nguyen, Thuc-Quyen; Heeger, Alan J

    2015-03-11

    Rational materials design and interface engineering are both essential to realize a high performance for tandem cells. Two identical bulk heterojunctions are connected in series using novel interconnection layers combining pH-neutral conjugated polyelectrolytes and a thin film of ZnO nanoparticles by a solution process. The best performing tandem cells achieve a power conversion efficiency of 11.3%, with 25% enhancement in efficiency compared with single cells, which arises primarily from the increased light absorption. PMID:25645197

  13. MR-Tandem: parallel X!Tandem using Hadoop MapReduce on Amazon Web Services

    PubMed Central

    Pratt, Brian; Howbert, J. Jeffry; Tasman, Natalie I.; Nilsson, Erik J.

    2012-01-01

    Summary: MR-Tandem adapts the popular X!Tandem peptide search engine to work with Hadoop MapReduce for reliable parallel execution of large searches. MR-Tandem runs on any Hadoop cluster but offers special support for Amazon Web Services for creating inexpensive on-demand Hadoop clusters, enabling search volumes that might not otherwise be feasible with the compute resources a researcher has at hand. MR-Tandem is designed to drop in wherever X!Tandem is already in use and requires no modification to existing X!Tandem parameter files, and only minimal modification to X!Tandem-based workflows. Availability and implementation: MR-Tandem is implemented as a lightly modified X!Tandem C++ executable and a Python script that drives Hadoop clusters including Amazon Web Services (AWS) Elastic Map Reduce (EMR), using the modified X!Tandem program as a Hadoop Streaming mapper and reducer. The modified X!Tandem C++ source code is Artistic licensed, supports pluggable scoring, and is available as part of the Sashimi project at http://sashimi.svn.sourceforge.net/viewvc/sashimi/trunk/trans_proteomic_pipeline/extern/xtandem/. The MR-Tandem Python script is Apache licensed and available as part of the Insilicos Cloud Army project at http://ica.svn.sourceforge.net/viewvc/ica/trunk/mr-tandem/. Full documentation and a windows installer that configures MR-Tandem, Python and all necessary packages are available at this same URL. Contact: brian.pratt@insilicos.com PMID:22072385

  14. Tandem Filter Development for Thermophotovoltaic Energy Conversion from January 2003 to February 2006

    SciTech Connect

    Fourspring PM

    2007-03-19

    The intent of this report is to summarize the tandem filter development for spectral control of thermophotovoltaic energy conversion from January 2003 to the termination of the program in February 2006 and to closeout tandem filter development in order to capture the knowledge gained from the development effort. Over the last three years, the goals of the tandem filter development have been the following: (1) Study the limits of the design of the interference optical coatings component of a tandem filter in order to develop higher performance designs; (2) Enhance the fabrication process of the optical interference coatings to increase the fidelity with the intended design and allow more complex, higher performing designs; (3) Support TPV module testing by providing tandem filters and assembly assistance; (4) Identify and develop materials for optical interference coatings that are stable at higher temperatures than current materials; and (5) Improve the understanding of the directional and spectral reflectance and transmittance characterization of the completed tandem filters to insure the veracity of the characterization data and to provide useful feedback to the tandem filter development process. This development effort has been a collaboration between KAPL and its contracted development partner, Rugate Technologies Inc.

  15. ''Flute'' instability in tandem mirrors

    SciTech Connect

    Timofeev, A.V.

    1983-05-01

    This analysis is based on the circumstance that flute-like waves in the end mirror systems of a tandem mirror convert into Alfven waves in the central solenoid. The effect of the end regions on the Alfven waves can be taken into account through boundary conditions at the ends of the central mirror system. A two-dimensional differential wave equation describing the plasma oscillations in a tandem mirror is reduced to a one-dimensional integral equation which determines the radial structure of the flutes in the end regions. If the growth rate is sufficiently high, this integral equation transforms into a differential equation. If the flute waves are stabilized by finite-Larmor-radius effects, the energy transfer into the central mirror system through the excitation of Alfven waves drives an instability of negative-energy waves.

  16. Nanocrystal assembly for tandem catalysis

    DOEpatents

    Yang, Peidong; Somorjai, Gabor; Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu

    2014-10-14

    The present invention provides a nanocrystal tandem catalyst comprising at least two metal-metal oxide interfaces for the catalysis of sequential reactions. One embodiment utilizes a nanocrystal bilayer structure formed by assembling sub-10 nm platinum and cerium oxide nanocube monolayers on a silica substrate. The two distinct metal-metal oxide interfaces, CeO.sub.2--Pt and Pt--SiO.sub.2, can be used to catalyze two distinct sequential reactions. The CeO.sub.2--Pt interface catalyzed methanol decomposition to produce CO and H.sub.2, which were then subsequently used for ethylene hydroformylation catalyzed by the nearby Pt--SiO.sub.2 interface. Consequently, propanal was selectively produced on this nanocrystal bilayer tandem catalyst.

  17. Nanocrystal bilayer for tandem catalysis

    NASA Astrophysics Data System (ADS)

    Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu; Huo, Ziyang; Habas, Susan E.; Soejima, Tetsuro; Aliaga, Cesar E.; Somorjai, Gabor A.; Yang, Peidong

    2011-05-01

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts.

  18. "Nanocrystal bilayer for tandem catalysis"

    SciTech Connect

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  19. Modeling and Simulation of Tandem Tollbooth Operations with Max-Algebra Approach

    NASA Astrophysics Data System (ADS)

    Hong, Young-Chae; Kim, Dong-Kyu; Kho, Seung-Young; Kim, Soo Wook; Yang, Hongsuk

    This study proposes a new model to simulate tandem tollbooth system in order to enhance planning and management of toll plaza facilities. A discrete-event stochastic microscopic simulation model is presented and developed to evaluate the operational performance of tandem tollbooth. Traffic behavior is represented using a set of mathematical and logical algorithms. Modified versions of Max-algebra approach are integrated into this new algorithm to simulate traffic operation at toll plazas. Computational results show that the benefit of tandem tollbooth depends on the number of serial tollbooth, service time and reaction time of drivers. The capacity of tandem tollbooth increases when service time follows a normal distribution rather than negative exponential distribution. Specifically, the lower variance of service time is, the better capacity tollbooth has. In addition, the ratio of driver's reaction time to service time affects the increasing ratio of the capacity extended by tollbooth.

  20. Short Tandem Repeat DNA Internet Database

    National Institute of Standards and Technology Data Gateway

    SRD 130 Short Tandem Repeat DNA Internet Database (Web, free access)   Short Tandem Repeat DNA Internet Database is intended to benefit research and application of short tandem repeat DNA markers for human identity testing. Facts and sequence information on each STR system, population data, commonly used multiplex STR systems, PCR primers and conditions, and a review of various technologies for analysis of STR alleles have been included.

  1. B-cell antigen receptor activates transcription factors NFAT (nuclear factor of activated T-cells) and NF-kappaB (nuclear factor kappaB) via a mechanism that involves diacylglycerol.

    PubMed

    Antony, P; Petro, J B; Carlesso, G; Shinners, N P; Lowe, J; Khan, W N

    2004-02-01

    Engagement of the B-cell antigen receptor (BCR) induces the activation of various transcription factors, including NFAT (nuclear factor of activated T-cells) and NF-kappaB (nuclear factor kappaB), which participate in long-term biological responses such as proliferation, survival and differentiation of B-lymphocytes. We addressed the biochemical basis of this process using the DT40 chicken B-cell lymphoma. We discovered that Bruton's tyrosine kinase (BTK) and phospholipase C-gamma2 (PLC-gamma2) are required to activate NFAT and NF-kappaB, and to produce the lipid second messenger diacylglycerol in response to BCR cross-linking. Therefore the functional integrity of the BTK/PLC-gamma2/diacylglycerol signalling axis is crucial for BCR-directed activation of both transcription factors NFAT and NF-kappaB. PMID:14748726

  2. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...the tandem to end office links (or a surrogate based on the proportion of copper...the tandem to end office links (or a surrogate based on the proportion of copper and...the tandem to end office links (or a surrogate based on the proportion of copper...

  3. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...the tandem to end office links (or a surrogate based on the proportion of copper...the tandem to end office links (or a surrogate based on the proportion of copper and...the tandem to end office links (or a surrogate based on the proportion of copper...

  4. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...the tandem to end office links (or a surrogate based on the proportion of copper...the tandem to end office links (or a surrogate based on the proportion of copper and...the tandem to end office links (or a surrogate based on the proportion of copper...

  5. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...the tandem to end office links (or a surrogate based on the proportion of copper...the tandem to end office links (or a surrogate based on the proportion of copper and...the tandem to end office links (or a surrogate based on the proportion of copper...

  6. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...the tandem to end office links (or a surrogate based on the proportion of copper...the tandem to end office links (or a surrogate based on the proportion of copper and...the tandem to end office links (or a surrogate based on the proportion of copper...

  7. Improved monolithic tandem solar cell

    SciTech Connect

    Wanlass, M.W.

    1991-04-23

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

  8. Tandem mirror technology demonstration facility

    SciTech Connect

    Not Available

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M/sup 2/) on an 8-m/sup 2/ test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m/sup 2/ and give the necessary experience for successful operation of an ETR.

  9. Optimizing a tandem disk model

    NASA Astrophysics Data System (ADS)

    Healey, J. V.

    1983-08-01

    The optimum values of the solidity ratio, tip speed ratio (TSR), and the preset angle of attack, the corresponding distribution, and the breakdown mechanism for a tandem disk model for a crosswind machine such as a Darrieus are examined analytically. Equations are formulated for thin blades with zero drag in consideration of two plane rectangular disks, both perpendicular to the wind flow. Power coefficients are obtained for both disks and comparisons are made between a single-disk system and a two-disk system. The power coefficient for the tandem disk model is shown to be a sum of the coefficients of the individual disks, with a maximum value of twice the Betz limit at an angle of attack of -1 deg and the TSR between 4-7. The model, applied to the NACA 0012 profile, gives a maximum power coefficient of 0.967 with a solidity ratio of 0.275 and highly limited ranges for the angle of attack and TSR.

  10. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    SciTech Connect

    Li, Guijun Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

    2014-06-09

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800?nm) and bottom (800–1100?nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  11. Tandem mass spectrometry: analysis of complex mixtures

    SciTech Connect

    Singleton, K.E.

    1985-01-01

    Applications of tandem mass spectrometry (MS/MS) for the analysis of complex mixtures results in increased specificity and selectivity by using a variety of reagent gases in both negative and positive ion modes. Natural isotopic abundance ratios were examined in both simple and complex mixtures using parent, daughter and neutral loss scans. MS/MS was also used to discover new compounds. Daughter scans were used to identify seven new alkaloids in a cactus species. Three of these alkaloids were novel compounds, and included the first simple, fully aromatic isoquinoline alkaloids reported in Cactaceae. MS/MS was used to characterize the chemical reaction products of coal in studies designed to probe its macromolecular structure. Negative ion chemical ionization was utilized to study reaction products resulting from the oxidation of coal. Possible structural units in the precursor coal were predicted based on the reaction products identified, aliphatic and aromatic acids and their anhydrides. The MS/MS method was also used to characterize reaction products resulting from coal liquefaction and/or extraction. These studies illustrate the types of problems for which MS/MS is useful. Emphasis has been placed on characterization of complex mixtures by selecting experimental parameters which enhance the information obtained. The value of using MS/MS in conjunction with other analytical techniques as well as the chemical pretreatment is demonstrated.

  12. Software dependability in the Tandem GUARDIAN system

    NASA Technical Reports Server (NTRS)

    Lee, Inhwan; Iyer, Ravishankar K.

    1995-01-01

    Based on extensive field failure data for Tandem's GUARDIAN operating system this paper discusses evaluation of the dependability of operational software. Software faults considered are major defects that result in processor failures and invoke backup processes to take over. The paper categorizes the underlying causes of software failures and evaluates the effectiveness of the process pair technique in tolerating software faults. A model to describe the impact of software faults on the reliability of an overall system is proposed. The model is used to evaluate the significance of key factors that determine software dependability and to identify areas for improvement. An analysis of the data shows that about 77% of processor failures that are initially considered due to software are confirmed as software problems. The analysis shows that the use of process pairs to provide checkpointing and restart (originally intended for tolerating hardware faults) allows the system to tolerate about 75% of reported software faults that result in processor failures. The loose coupling between processors, which results in the backup execution (the processor state and the sequence of events) being different from the original execution, is a major reason for the measured software fault tolerance. Over two-thirds (72%) of measured software failures are recurrences of previously reported faults. Modeling, based on the data, shows that, in addition to reducing the number of software faults, software dependability can be enhanced by reducing the recurrence rate.

  13. Hydrodynamic studies on two traveling wavy foils in tandem arrangement

    NASA Astrophysics Data System (ADS)

    Deng, Jian; Shao, Xue-Ming; Yu, Zhao-Sheng

    2007-11-01

    In this study, the hydrodynamic interactions between two tandem foils undergoing fishlike swimming motion are investigated numerically by solving the Navier-Stokes equations with the immersed-boundary method. The two foils represent two tandem propellers attached on a concept ship. The thrusts and efficiencies at three typical Strouhal numbers, i.e., St =0.4, 0.6, and 0.8, are investigated. The results show that a fish situated directly behind another one does not always undergo a lower thrust. Whether it experiences a thrust enhancement or reduction depends on the Strouhal number. At a relatively low Strouhal number (e.g., St =0.4), the usual wake drag-reduction effect predominates over the drag-enhancement effect caused by the reverse von Kármán vortices, resulting in a thrust enhancement. The opposite happens at a relatively high Strouhal number (e.g., St =0.8). The downstream fish can benefit from the upstream one by slalom between the vortices rather than through them. For the upstream fish, the thrusts and efficiencies for all Strouhal numbers studied are higher than those for a single fish when the two fish are closely spaced, and approach those for a single fish as the spacing is increased.

  14. Cytokine dependent inverse regulation of CD54 (ICAM1) and major histocompatibility complex class I antigens by nuclear factor kappaB in HEp2 tumor cell line: effect on the function of natural killer cells.

    PubMed

    Jewett, Anahid; Wang, Mei-Ying; Teruel, Antonia; Poupak, Ziaei; Bostanian, Zohrab; Park, No-Hee

    2003-05-01

    The aim of this study is to investigate the mechanisms by which elevated nuclear factor kappaB (NFkappaB) activity in HEp2 cells can modulate the function and survival of immune effector cells. Inhibition of NFkappaB functional activity by stable expression of IkappaB super-repressor rendered HEp2 cells (HEp2-IkappaB((S32AS36A))) susceptible to natural killer (NK) cell mediated cytotoxicity. Increase in surface ICAM1 expression was greater on HEp2-IkappaB((S32AS36A)) cells than on the surface of vector alone transfected HEp2 cells when these cells were treated with IFN-gamma. In contrast, tumor necrosis factor alpha (TNF-alpha) treatment augmented ICAM-1 expression on the surface of vector-alone transfected HEp2 cells and not on the HEp2-IkappaB((S32AS36A)) cells. Moreover, synergistic augmentation of ICAM-1 by a combination of TNF-alpha and interferon-gamma (IFN-gamma) treatment was completely abrogated on the surface of HEp2-IkappaB((S32AS36A)) cells. The addition of blocking antibody to ICAM-1 surface antigen partially inhibited the increased cytotxicity mediated by interleukin-2 treated NK cells against HEp2-IkappaB((S32AS36A)) cells. In contrast to ICAM-1, the expression of major histocompatibility complex (MHC) class I antigens were downregulated when the function of nuclear NFkappaB was inhibited in HEp2 cells. The addition of IFN-gamma to HEp2-kappaB((S32AS36A)) cells increased the expression of MHC class I antigen and rendered these cells less susceptible to NK cell mediated cytotoxicity. Secretion of IFN-gamma and granulocyte macrophage-colony-stimulating factor (GM-CSF) by NK cells was also significantly increased in the presence of HEp2-IkappaB((S32AS36A)) cells, and the treatment of these tumor cells with IFN-gamma prior to their addition to the cultures of NK cells decreased the released IFN-gamma and GM-CSF by NK cells. However, the levels of NK cell mediated cytotoxicity and IFN-gamma secretion remained significantly higher in the presence of both untreated and IFN-gamma treated HEp2-IkappaB((S32AS36A)) cells when compared with vector-alone transfected HEp2 cells. Thus, NFkappaB regulates inversely the expression of ICAM-1 and MHC class I antigens on HEp2 tumor cells and this may contribute to the resistance of these cells to NK cell mediated cytotoxicity. PMID:12691701

  15. Growing bottleneck features for tandem ASR 

    E-print Network

    Frankel, Joe; Wang, Dong; King, Simon

    2008-01-01

    We present a method for training bottleneck MLPs for use in tandem ASR. Experiments on meetings data show that this approach leads to improved performance compared with training MLPs from a random initialization.

  16. Initial operation of ORIC with tandem injection

    SciTech Connect

    Ludemann, C.A.; Ball, J.B.; Beckers, R.M.; Cleary, T.P.; Hudson, E.D.; Lord, R.S.; Martin, J.A.; Milner, W.T.; Mosko, S.W.; Ziegler, N.F.

    1981-01-01

    Coupled operation of the 25 MV tandem and ORIC was achieved on January 27, 1981. The initial beam was 324 MeV /sup 16/O/sup 8 +/ followed shortly by oxygen at 400 MeV-the maximum design energy. Following additional installation and testing of the tandem, coupled operation for a nuclear physics experiment began in August. Performance of the system was in close agreement with that predicted from calculations.

  17. Small GTPase Rho signaling is involved in {beta}1 integrin-mediated up-regulation of intercellular adhesion molecule 1 and receptor activator of nuclear factor {kappa}B ligand on osteoblasts and osteoclast maturation

    SciTech Connect

    Hirai, Fumihiko; Nakayamada, Shingo; Okada, Yosuke; Saito, Kazuyoshi; Kurose, Hitoshi; Mogami, Akira; Tanaka, Yoshiya . E-mail: tanaka@med.uoeh-u.ac.jp

    2007-04-27

    We assessed the characteristics of human osteoblasts, focusing on small GTPase Rho signaling. {beta}1 Integrin were highly expressed on osteoblasts. Engagement of {beta}1 integrins by type I collagen augmented expression of intercellular adhesion molecule 1 (ICAM-1) and receptor activator of nuclear factor {kappa}B ligand (RANKL) on osteoblasts. Rho was activated by {beta}1 stimulation in osteoblasts. {beta}1 Integrin-induced up-regulation of ICAM-1 and RANKL was inhibited by transfection with adenoviruses encoding C3 transferase or pretreated with Y-27632, specific Rho and Rho-kinase inhibitors. Engagement of {beta}1 integrin on osteoblasts induced formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNC) in a coculture system of osteoblasts and peripheral monocytes, but this action was completely abrogated by transfection of C3 transferase. Our results indicate the direct involvement of Rho-mediated signaling in {beta}1 integrin-induced up-regulation of ICAM-1 and RANKL and RANKL-dependent osteoclast maturation. Thus, Rho-mediated signaling in osteoblasts seems to introduce major biases to bone resorption.

  18. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Tandem-switched transport and tandem charge. 69... 69.123, per-minute common transport charges described in paragraph (a)(1) of this section shall be... pricing zones as described in section 69.123, per-minute common transport charges described in...

  19. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Tandem-switched transport and tandem charge. 69... 69.123, per-minute common transport charges described in paragraph (a)(1) of this section shall be... pricing zones as described in section 69.123, per-minute common transport charges described in...

  20. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Tandem-switched transport and tandem charge. 69... 69.123, per-minute common transport charges described in paragraph (a)(1) of this section shall be... pricing zones as described in section 69.123, per-minute common transport charges described in...

  1. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Tandem-switched transport and tandem charge. 69... 69.123, per-minute common transport charges described in paragraph (a)(1) of this section shall be... pricing zones as described in section 69.123, per-minute common transport charges described in...

  2. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Tandem-switched transport and tandem charge. 69... 69.123, per-minute common transport charges described in paragraph (a)(1) of this section shall be... pricing zones as described in section 69.123, per-minute common transport charges described in...

  3. Brookhaven National Laboratory Tandem Facility

    SciTech Connect

    Lindgren, R.

    1983-01-01

    Our MP7 accelerator has had about 70% utilization in the past year, clocking 6000 hours, of which approximately 10% was at terminal voltages between 14.75 and 16.25 MV. This pelletron system, installed in 1977, has logged 40,000 hours, and to date has broken five chains, three in the past four months. There are still two chains that have gone the total time. The injector machine, MP6, with its three chains installed in 1980, has accumulated 18000 hours with no chain failures. About six percent of the operating time in the past year was devoted to four-stage operation or accel-decel production of low energy highly stripped ions, for atomic physics experiments. This type of operation was improved by the addition of a remotely inserted gridded lens at the exit of the special last acceleration tube. Some examples of the beams we have produced are 2.5 MeV /sup 35/Cl, Q16 10 na, 8 MeV /sup 32/S, Q15 .5 na, 2.5 MeV /sup 19/F, 09 20 na. We have acquired two General Ionex 860, Roy Middleton Mark VII sputter sources. One of these we have mounted on an ion pump, with integral focus lens, steerers and perture, and dedicated it to /sup 14/C use, for injection into MP7. To date, from June, we have used it for four runs totaling 32 8-hour shifts, and 116 ..mu..a hours, with a maximum injected beam of 2.5 ..mu..a. The other 860 sputter source was used in a pulse mode to test for possible injection of the tandem accelerated heavy ion beam into BNL's AGS.

  4. Development of a rapid capture-cum-detection method for Escherichia coli O157 from apple juice comprising nano-immunomagnetic separation in tandem with surface enhanced Raman scattering.

    PubMed

    Najafi, Roya; Mukherjee, Shubhasish; Hudson, Jim; Sharma, Anup; Banerjee, Pratik

    2014-10-17

    A combined capture and detection method comprising of nano-immunomagnetic separation (NIMS) and surface enhanced Raman spectroscopy (SERS) was developed to detect Escherichia coli O157 from liquid media including apple juice. The capture antibodies (cAbs) were immobilized on magnetite-gold (Fe3O4/Au) magnetic nanoparticles (MNPs) which were used for separation and concentration of the E. coli O157 cells from model liquid food matrix. The capture efficiency (CE) for E. coli O157 using MNP was found to be approximately 84-94%. No cross reactivity was observed with background non-target organisms. There was a significant difference in the mean CE of bacteria captured by MNP and commercially sourced immunomagnetic microbeads (p<0.05). For the detection of target pathogen, SERS labels were prepared by conjugating gold nanoparticles with Raman reporter molecules and the detector antibody (dAb). Au-Raman label-dAb was interacted with gold coated MNP-cAb-E. coli O157 complex. The ability of this immunoassay to detect E. coli O157 in apple juice was investigated. We have successfully applied the synthesized Fe3O4/Au nanoclusters to E. coli O157 detection in apple juice using the SERS method. The lowest detectable bacterial cell concentration in apple juice was 10(2)CFU/mL with a total analysis time of less than an hour. This method presents a convenient way of preconcentration, separation, and detection of low levels of target pathogen from liquid food matrix. PMID:25133877

  5. LLNL tandem mirror experiment (TMX) upgrade vacuum system

    SciTech Connect

    Pickles, W.L.; Chargin, A.K.; Drake, R.P.; Hunt, A.L.; Lang, D.D.; Murphy, J.J.; Poulsen, P.; Simonen, T.C.; Batzer, T.H.; Stack, T.P.; Wong, R.L.

    1982-04-01

    The tandem mirror experiment (TMX) upgrade is a large, tandem, magnetic-mirror fusion experiment with stringent requirements on base pressure (10/sup -8/ Torr), low H reflux from the first walls, and peak gas pressure (5 x 10/sup -7/ Torr) due to neutral beam gas during plasma operation. The 225 m/sup 3/ vacuum vessel is initially evacuated by turbopumps. Cryopumps provide a continuous sink for gases other than helium, deuterium, and hydrogen. The neutral beam system introduces up to 480 l/s of H or D. The hydrogen isotopes are pumped at very high speed by titanium sublimed onto two cylindrical radially separated stainless steel quilted liners with a total surface area of 540 m/sup 2/. These surfaces (when cooled to about 80 K) provide a pumping speed of 6 x 10/sup 7/ l/s for hydrogen. The titanium getter system is programmable and is used for heating as well as gettering. The inner plasma liner can be operated at elevated temperatures to enhance migration of gases away from the surfaces close to the plasma. Glow discharge cleaning is part of the pumpdown procedure. The design features are discussed in conjunction with the operating procedures developed to manage the dynamic vacuum conditions.

  6. Tandem gene amplification mediates copper resistance in yeast.

    PubMed Central

    Fogel, S; Welch, J W

    1982-01-01

    Resistance to copper's toxicity in yeast is controlled by the CUP1r locus. This gene was cloned by transforming sensitive recipients (cup1(8)) with a collection of hybrid DNA molecules, consisting of random yeast DNA fragments inserted into the vector YRp7. Four resistant transformants were studied in detail. Autonomously replicating or integrated by homologous recombination into chromosomal sites, the corresponding plasmids and several subclones confer resistance on sensitive recipients carrying the natural variant allele, cup1(8). Tetrad analysis and genetic mapping established that integration occurs typically at the cup1(8) site located 28 centimorgans distal to thr1, a chromosome VIII marker. Restriction endonuclease cleavage and electrophoretic mobility studies revealed that the CUP1r locus consists of a tandem array of repetitive units. Each unit is 1.95 kilobases in length and contains single sites for Kpn I and Xba I and two Sau3A sites. The sensitive allele represents one repeat and the resistant allele embraces 15 tandemly arrayed repeat units. Progressive selections in higher copper concentrations establish strains with markedly enhanced resistance. Resistance, we propose, is mediated by a gene amplification mechanism based on unequal sister chromatid exchange. Images PMID:6291039

  7. High performance polymer tandem solar cell

    PubMed Central

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2015-01-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. PMID:26669577

  8. High performance polymer tandem solar cell.

    PubMed

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd Rashid Bin; Jang, Jin

    2015-01-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. PMID:26669577

  9. Tandem-mirror program: status and projection

    SciTech Connect

    Van Atta, C.M.

    1981-03-12

    Construction of MFTF-B is scheduled for completion in 1985. Results of experiments in TMX-U and MFTF-B will permit the design of the D-T burning tandem-mirror next-step facility (TMNS) in which physics issues will not be at issue. TMNS will be a facility for engineering research and development. The end cells of TMNS are expected to be appropriate for a tandem-mirror demonstration fusion reactor (TMR), construction of which should begin about 1986 for operation in the 1990's.

  10. Experimental study on tandem pumped fiber amplifier

    NASA Astrophysics Data System (ADS)

    Xiao, Hu; Xu, Jiangming; Wu, Wuming; Zhou, Pu; Xu, Xiaojun

    2012-07-01

    We present the experimental results of a 1083 nm fiber amplifier tandem pumped by 1030 nm fiber laser. The output characteristics of the tandem pumped amplifier with cladding-pump and core-pump schemes are both investigated. The 1083 nm signal laser has not been efficiently amplified when cladding-pumped by 1030 nm laser for the weak absorption of the gain fiber. The core-pump scheme works well with the amplifier. The output properties with different gain fiber length are experimentally investigated. The maximum output power is 2.4 W with power conversion efficiency of 60%.

  11. Tandem mirror thermal barrier experimental program plan

    SciTech Connect

    Coensgen, F.H.; Drake, R.P.; Simonen, T.C.

    1980-01-02

    This report describes an experimental plan for the development of the Tandem Mirror Thermal Barrier. Included is: (1) a description of thermal barrier related physics experiments; (2) thermal barrier related experiments in the existing TMX and Phaedrus experiments; (3) a thermal barrier TMX upgrade; and (4) initiation of investigations of axisymmetric magnetic geometry. Experimental studies of the first two items are presently underway. Results are expected from the TMX upgrade by the close of 1981 and from axisymmetric tandem mirror experiments at the end of 1983. Plans for Phaedrus upgrades are developing for the same period.

  12. Antiosteoclastogenesis activity of a CO2 laser antagonizing receptor activator for nuclear factor kappaB ligand-induced osteoclast differentiation of murine macrophages

    NASA Astrophysics Data System (ADS)

    Kuo, Chun-Liang; Kao, Chia-Tze; Fang, Hsin-Yuan; Huang, Tsui-Hsien; Chen, Yi-Wen; Shie, Ming-You

    2015-03-01

    Macrophage cells are the important effector cells in the immune reaction which are indispensable for osteoclastogenesis; their heterogeneity and plasticity renders macrophages a primer target for immune system modulation. In recent years, there have been very few studies about the effects of macrophage cells on laser treatment-regulated osteoclastogenesis. In this study, RAW 264.7 macrophage cells were treated with RANKL to regulate osteoclastogenesis. We used a CO2 laser as a model biostimulation to investigate the role of osteoclastogenic. We also evaluated cell viability, cell death and cathepsin K expression. The CO2 laser inhibited a receptor activator of the NF-?B ligand (RANKL)-induced formation of osteoclasts during the osteoclast differentiation process. It was also found that irradiation for two times reduced RANKL-enhanced TRAP activity in a dose-dependent manner. Furthermore, CO2 laser-treatment diminished the expression and secretion of cathepsin K elevated by RANKL and was concurrent with the inhibition of TRAF6 induction and NF-?B activation. The current report demonstrates that CO2 laser abrogated RANKL-induced osteoclastogenesis by retarding osteoclast differentiation. The CO2 laser can modulate every cell through dose-dependent in vitro RANKL-mediated osteoclastogenesis, such as the proliferation and fusion of preosteoclasts and the maturation of osteoclasts. Therefore, the current results serve as an improved explanation of the cellular roles of macrophage cell populations in osteoclastogenesis as well as in alveolar bone remodeling by CO2 laser-treatment.

  13. 47 CFR 69.129 - Signalling for tandem switching.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Signalling for tandem switching. 69.129 Section 69.129 Telecommunication... § 69.129 Signalling for tandem switching. A charge that is expressed in...for provision of signalling for tandem switching. [59 FR 32930, June 27,...

  14. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Canard or tandem wing configurations. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  15. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Canard or tandem wing configurations. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  16. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Canard or tandem wing configurations. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  17. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Canard or tandem wing configurations. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  18. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Canard or tandem wing configurations. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  19. Technology for large tandem mirror experiments

    SciTech Connect

    Thomassen, K.I.

    1980-09-04

    Construction of a large tandem mirror (MFTF-B) will soon begin at Lawrence Livermore National Laboratory (LLNL). Designed to reach break-even plasma conditions, the facility will significantly advance the physics and technology of magnetic-mirror-based fusion reactors. This paper describes the objectives and the design of the facility.

  20. Note on Hovering Turns with Tandem Helicopters

    NASA Technical Reports Server (NTRS)

    Reeder, John P; Tapscott, Robert J

    1955-01-01

    The source of an appreciable pitching-moment difference between left and right hovering turns for a tandem helicopter is described. The difference in pitching moment results from the difference in rotational speed of the counter rotating rotors with respect to the air while the helicopter is turning.

  1. Edge diagnostics for tandem mirror machines

    SciTech Connect

    Allen, S.L.

    1984-09-14

    The edge plasma in a tandem mirror machine shields the plasma core from cold neutral gas and impurities. A variety of diagnostics are used to measure the fueling, shielding, and confinement of the edge plasma in both the end plug and central cell regions. Fast ion gauges and residual gas analyzers measure the gas pressure and composition outside of the plasma. An array of Langmuir probes is used to measure the electron density and temperature. Extreme ultraviolet (euv) and visible spectroscopy are used to measure both the impurity and deuterium densities and to estimate the shielding factor for the core plasma. The linear geometry of a tandem mirror also allows direct measurements of the edge plasma by sampling the ions and electrons lost but the ends of the machine. Representative data obtained by these diagnostics during operation of the Tandem Mirror Experiment (TMX) and Tandem Mirror Experiment-Upgrade (TMX-U) experiments are presented. Diagnostics that are currently being developed to diagnose the edge plasma are also discussed.

  2. MASPIC: Intensity-Based Tandem Mass Spectrometry Scoring Scheme That Improves Peptide Identification at High Confidence

    SciTech Connect

    Narasimhan, Chandrasegaran NMN; Tabb, Dave L; Verberkmoes, Nathan C; Thompson, Melissa R; Hettich, Robert {Bob} L; Uberbacher, Edward C

    2005-01-01

    Algorithmic search engines bridge the gap between large tandem mass spectrometry data sets and the identification of proteins associated with biological samples. Improvements in these tools can greatly enhance biological discovery. We present a new scoring scheme for comparing tandem mass spectra with a protein sequence database. The MASPIC (Multinomial Algorithm for Spectral Profile-based Intensity Comparison) scorer converts an experimental tandem mass spectrum into a m/z profile of probability and then scores peak lists from potential candidate peptides using a multinomial distribution model. The MASPIC scoring scheme incorporates intensity, spectral peak density variations, and m/z error distribution associated with peak matches into a multinomial distribution. The scoring scheme was validated on two standard protein mixtures and an additional set of spectra collected on a complex ribosomal protein mixture from Rhodopseudomonas palustris. The results indicate a 5-15% improvement over Sequest for high-confidence identifications. The performance gap grows as sequence database size increases. Additional tests on spectra from proteinase-K digest data showed similar performance improvements demonstrating the advantages in using MASPIC for studying proteins digested with less specific proteases. All these investigations show MASPIC to be a versatile and reliable system for peptide tandem mass spectral identification.

  3. Dye Sensitized Tandem Photovoltaic Cells

    SciTech Connect

    Barber, Greg D.

    2009-12-21

    This work provided a new way to look at photoelectrochemical cells and their performance. Although thought of as low efficiency, a the internal efficiency of a 9% global efficiency dye sensitized solar cell is approximately equal to an 18% efficient silicon cell when each is compared to their useful spectral range. Other work undertaken with this contract also reported the first growth oriented titania and perovskite columns on a transparent conducting oxide. Other work has shown than significant performance enhancement in the performance of dye sensitized solar cells can be obtained through the use of coupling inverse opal photonic crystals to the nanocrystalline dye sensitized solar cell. Lastly, a quick efficient method was developed to bond titanium foils to transparent conducting oxide substrates for anodization.

  4. Tandem microwave waste remediation and decontamination system

    DOEpatents

    Wicks, George G. (North Aiken, SC); Clark, David E. (Gainesville, FL); Schulz, Rebecca L. (Gainesville, FL)

    1999-01-01

    The invention discloses a tandem microwave system consisting of a primary chamber in which microwave energy is used for the controlled combustion of materials. A second chamber is used to further treat the off-gases from the primary chamber by passage through a susceptor matrix subjected to additional microwave energy. The direct microwave radiation and elevated temperatures provide for significant reductions in the qualitative and quantitative emissions of the treated off gases. The tandem microwave system can be utilized for disinfecting wastes, sterilizing materials, and/or modifying the form of wastes to solidify organic or inorganic materials. The simple design allows on-site treatment of waste by small volume waste generators.

  5. DDES and IDDES of tandem cylinders.

    SciTech Connect

    Balakrishnan, R.; Garbaruk, A.; Shur, M.; Strelets, M.; Spalart, P.; New Technologies and Services - Russia; St.-Peterburg State Polytechnic Univ.; Boeing Commercial Airplanes

    2010-09-09

    The paper presents an overview of the authors contribution to the BANC-I Workshop on the flow past tandem cylinders (Category 2). It includes an outline of the simulation approaches, numerics, and grid used, the major results of the simulations, their comparison with available experimental data, and some preliminary conclusions. The effect of varying the spanwise period in the simulations is strong for some quantities, and not others.

  6. Current and lattice matched tandem solar cell

    DOEpatents

    Olson, Jerry M. (Lakewood, CO)

    1987-01-01

    A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga.sub.x In.sub.1-x P (0.505.ltoreq.X.ltoreq.0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

  7. Brookhaven National Laboratory Tandem accelerator upgrading program

    SciTech Connect

    Thieberger, P.; Manni, M.A.; Lindgren, R.; McKeown, M.; Carlson, C.; Wegner, H.E.

    1981-01-01

    The three-stage Tandem Van de Graaff accelerator facility at Brookhaven National Laboratory has undergone various upgrading programs since the early 1970's. The original 10 MV waranteed MP Van de Graaff accelerator of 1970 now operates in excess of 14 MV because of many improvements over the years: the purpose of this paper is to report on the most recent improvements which have been completed and also on those that are presently under construction and being implemented.

  8. TandEM: Titan and Enceladus mission

    USGS Publications Warehouse

    Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, C.; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, J.; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, C.D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa

    2009-01-01

    TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfi??re) and possibly several landing probes to be delivered through the atmosphere. ?? Springer Science + Business Media B.V. 2008.

  9. Locating tandem repeats in weighted sequences in proteins

    PubMed Central

    2013-01-01

    A weighted biological sequence is a string in which a set of characters may appear at each position with respective probabilities of occurrence. We attempt to locate all the tandem repeats in a weighted sequence. A repeated substring is called a tandem repeat if each occurrence of the substring is directly adjacent to each other. By introducing the idea of equivalence classes in weighted sequences, we identify the tandem repeats of every possible length using an iterative partitioning technique. We also present the algorithm for recording the tandem repeats, and prove that the problem can be solved in O(n2) time. PMID:23815711

  10. 47 CFR 36.124 - Tandem switching equipment-Category 2.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Tandem switching equipment-Category 2. 36.124 Section...Central Office Equipment § 36.124 Tandem switching equipment—Category 2. (a) Tandem switching equipment is contained in Accounts...

  11. Tandem robot control system and method for controlling mobile robots in tandem

    SciTech Connect

    Hayward, David R.; Buttz, James H.; Shirey, David L.

    2002-01-01

    A control system for controlling mobile robots provides a way to control mobile robots, connected in tandem with coupling devices, to navigate across difficult terrain or in closed spaces. The mobile robots can be controlled cooperatively as a coupled system in linked mode or controlled individually as separate robots.

  12. The Naples University 3 MV tandem accelerator

    SciTech Connect

    Campajola, L.; Brondi, A.

    2013-07-18

    The 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented.

  13. HRIBF Tandem Accelerator Radiation Safety System Upgrade

    SciTech Connect

    Blankenship, J.L.; Juras, R.C.

    1998-11-04

    The HRIBF Tandem Accelerator Radiation Safety System was designed to permit experimenters and operations staff controlled access to beam transport and experiment areas with accelerated beam present. Neutron-Gamma detectors are mounted in eaeh area at points of maximum dose rate and the resulting signals are integrated by redundan~ circuitry; beam is stopped if dose rate or integrated dose exceeds established limits. This paper will describe the system, in use for several vears at the HRIBF, and discuss changes recently made to modernize the system and to make the system compliant with DOE Order 5480.25 and related ORNL updated safety rules.

  14. Method of fabricating bifacial tandem solar cells

    DOEpatents

    Wojtczuk, Steven J; Chiu, Philip T; Zhang, Xuebing; Gagnon, Edward; Timmons, Michael

    2014-10-07

    A method of fabricating on a semiconductor substrate bifacial tandem solar cells with semiconductor subcells having a lower bandgap than the substrate bandgap on one side of the substrate and with subcells having a higher bandgap than the substrate on the other including, first, growing a lower bandgap subcell on one substrate side that uses only the same periodic table group V material in the dislocation-reducing grading layers and bottom subcells as is present in the substrate and after the initial growth is complete and then flipping the substrate and growing the higher bandgap subcells on the opposite substrate side which can be of different group V material.

  15. A Hybrid Approach To Tandem Cylinder Noise

    NASA Technical Reports Server (NTRS)

    Lockard, David P.

    2004-01-01

    Aeolian tone generation from tandem cylinders is predicted using a hybrid approach. A standard computational fluid dynamics (CFD) code is used to compute the unsteady flow around the cylinders, and the acoustics are calculated using the acoustic analogy. The CFD code is nominally second order in space and time and includes several turbulence models, but the SST k - omega model is used for most of the calculations. Significant variation is observed between laminar and turbulent cases, and with changes in the turbulence model. A two-dimensional implementation of the Ffowcs Williams-Hawkings (FW-H) equation is used to predict the far-field noise.

  16. Flute waves in a tandem mirror

    SciTech Connect

    Mikhailovskaya, L.V.

    1984-03-01

    Stability conditions are derived for flute waves in a short tandem mirror stabilized by end cells with a min B. The frequency spectrum of the flute waves is analyzed. Those conditions under which the resonant excitation of waves by ions and electrons must be taken into account are found. When end cells without a min B are added to a central mirror system, the system becomes destabilized as the result of resonant excitation of waves at a frequency near the precession frequency of ions having a finite energy distribution.

  17. Stereoscopic images in confocal (tandem scanning) microscopy.

    PubMed

    Boyde, A

    1985-12-13

    Stereoscopic pair images with parallel projection geometry are obtained by through-focusing along two inclined axes while recording two (summed and stacked) images with a microscope with a very shallow depth of field. The two stack images sample the same depth slice of translucent or reflective specimens. The method will work most conveniently with a tandem scanning microscope (a direct-view, confocal scanning optical microscope). This is a direct method for recording stereo images that can be used to the limit of resolution in optical microscopy. It demonstrates a previously unrealized advantage of confocal optical microscopy. PMID:4071051

  18. High-sensitivity mass spectrometry with a tandem accelerator

    SciTech Connect

    Henning, W.

    1983-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems.

  19. ERROR VISUALIZATION FOR TANDEM ACOUSTIC MODELING ON THE AURORA TASK

    E-print Network

    Ellis, Dan

    ERROR VISUALIZATION FOR TANDEM ACOUSTIC MODELING ON THE AURORA TASK Manuel J. Reyes. This structure reduces the error rate on the Aurora 2 noisy English digits task by more than 50% compared development of tandem systems showed an improvement in the performance on the Aurora task [2] of these systems

  20. A tandem-based compact dual-energy gamma generator

    SciTech Connect

    Persaud, A.; Kwan, J.W.; Leitner, M.; Leung, K.N.; Ludewigt, B.; Tanaka, N.; Waldron, W.; Wilde, S.; Antolak, A.J.; Morse, D.H.; Raber, T.

    2009-11-11

    A dual-energy tandem-type gamma generator has been developed at E.O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications.

  1. APPLICATION NOTE SILVER Helps Assign Peptides to Tandem

    E-print Network

    Roth, Frederick

    APPLICATION NOTE SILVER Helps Assign Peptides to Tandem Mass Spectra Using Intensity-Based Scoring" peptide-spectrum matches (PSMs). SILVER is web-based software that assists manual curation of tandem mass. The SILVER interface provides a visual representation of match quality between each candidate fragment ion

  2. Speckle-phase measurement in a tandem-vortex coronagraph.

    PubMed

    Serabyn, Eugene; Wallace, J Kent; Mawet, Dimitri

    2011-10-01

    A tandem-vortex coronagraph can in theory enable high-contrast imaging behind a classical on-axis telescope. Here we point out that a tandem-vortex coronagraph configuration can also directly enable the measurement of the phases of focal-plane speckles, thereby allowing for their suppression in the resultant high-contrast image. PMID:22016212

  3. Tandem-type pulse tube refrigerator without reservoir

    NASA Astrophysics Data System (ADS)

    Ki, Taekyung; Jeong, Sangkwon; Ko, Junseok; Park, Jiho

    2015-12-01

    In this paper, a tandem-type pulse tube refrigerator without a reservoir is discussed and investigated. For its practical application a tandem-type compressor is designed to generate two pulsating pressure waves with opposite phases, simultaneously. A tandem-type pulse tube refrigerator consists of a tandem-type compressor and two identical pulse tube refrigerators. The two identical pulse tube refrigerators share the same heat exchangers and one can be connected with the other by an inertance tube without a reservoir. In this proposed configuration, the mechanical vibration and temperature oscillations in the cold-end heat exchanger can be internally suppressed due to its intrinsic opposite-characteristic operation. To examine the quantitative evaluation of the tandem feature which does not require a reservoir in the pulse tube, an evolutionary approach has been attempted. A general structure of a pulse tube refrigerator is modified into tandem Stirling-type and GM-type machines and the transformed configuration has been simulated for tandem operation. The simulation results clearly demonstrate that a properly designed tandem-type pulse tube refrigerator without a reservoir can function favorably.

  4. The Shaft Torque of a Tandem Axial-Piston Pump

    E-print Network

    Manring, Noah D.

    that is experienced when stand- ing near a lawn mower or riding on a subway. In the past, there have been many for describing the theoretical torque ripple of a tandem pump design. This equation is also a function point of view for a tandem axial-piston pump design. Literature Review. Over the past 25 years

  5. Form-Focused Interaction in Online Tandem Learning

    ERIC Educational Resources Information Center

    O'Rourke, Breffni

    2005-01-01

    Tandem language learning--a configuration involving pairs of learners with complementary target/native languages--is an underexploited but potentially very powerful use of computer-mediated communication (CMC) in second-language pedagogy. Tandem offers the benefits of authentic, culturally grounded interaction, while also promoting a pedagogical…

  6. Theoretical studies in tandem mirror physics

    SciTech Connect

    Cohen, R.H.; Auerbach, S.P.; Baldwin, D.E.; Byers, J.A.; Chen, Y.J.; Cohen, B.I.; Freis, R.P.; Gilmore, J.M.; Hammer, J.H.; Kaiser, T.B.

    1984-07-17

    Recent developments in six areas of tandem-mirror theory are explored. Specifically, FLR terms (including electric-field drift) have been added to our 3-D paraxial MHD equilibrium code. Our low-frequency MHD stability analysis with FLR, which previously included only m/sub theta/ = 1 rigid perturbations, has been extended to incorporate moderate m/sub theta/, rotational drive, finite-beta effects on wall stabilization, and the well-digging effect of energetic electrons by using three computational techniques. In addition, we have examined the microstability of relativistic electrons with a loss-cone distribution, emphasizing the whistler and cyclotron-maser instabilities. We have also studied techniques for controlling radial transport, including the floating of segmented end plates and the tuning of transition-region coils, and have quantified the residual transport in a tandem mirror with axisymmetric throttle coils. Earlier work on the effect of ECRH on potentials in thermal-barrier cells has been extended. The transition between the weak- and strong-heating regimes has been examined using Fokker-Planck and Monte Carlo codes; an analytic model for the potentials relative to the end wall has been developed. Finally, our investigation of drift-frequency pumping of thermal-barrier ions has demonstrated that pumping is optimized when the magnetic fluctuation is perpendicular to both the unperturbed field and the thin fan, and that an adequate pumping rate is obtainable in future machines.

  7. The physiological effects of cycling on tandem and single bicycles

    PubMed Central

    Seifert, J; Bacharach, D; Burke, E; Langenfeld, M; Snyder, A

    2003-01-01

    Objective: The purpose of this field study was to compare the physiological responses from cycling on a tandem road bicycle to those from cycling on a single road bicycle. Methods: Nine pairs of experienced, recreational tandem cyclists rode a tandem or their single bicycle for 5 min at each velocity of 19.3, 22.5, 25.8, and 29.0 kph on a flat, paved surface. Heart rate (HR), rating of perceived exertion (RPE), and lactic acid (LA) data were collected after each interval. Results: Riding a tandem resulted in lower HR, RPE, and LA mean values across the four velocities compared to the single bicycle. Mean (SD) HR, RPE, and LA for tandem and single bicycles were 126 (20.7) v 142 (20.1) bpm, 10.1 (1.7) v 11.3 (2.6), and 1.46 (1.0) mM/L v 2.36 (1.7) mM/L, respectively. No position differences were observed between the captain and stoker (front and rear positions) when both were on the tandem. Stokers had significantly lower HR, LA, and RPE values when they rode a tandem compared to a single bicycle. No statistical differences were observed between bicycles for the captains. When on the single bicycle, captains exhibited significantly lower HR, RPE, and LA values than stokers. Conclusion: Cycling on a tandem resulted in lower physiological stress than when cycling at the same velocity on a single bicycle. Cyclists were able to ride from 4.8–8.0 kph faster on a tandem than on a single bicycle at similar physiological stress. Apparently, stokers can add to power output on a tandem without adding significantly to wind resistance. PMID:12547743

  8. Tandem Time-of-Flight (TOF/TOF) Mass Spectrometry and Proteomics†

    PubMed Central

    Cotter, Robert J.; Iltchenko, Serguei; Wang, Dongxia; Gundry, Rebekah

    2010-01-01

    A dual reflectron tandem time-of-flight (TOF/TOF) mass spectrometer reported in 1993 gave rise to the invention and development of the curved-field reflectron (CFR) for focusing product ions. The CFR is used in this case as the second mass analyzer in a tandem instrument (based on the Kratos AXIMA CFR) in which the first mass analyzer is a linear TOF that focuses ions by pulsed extraction. Because ions can be focused over a broad range of kinetic energies, deceleration of precursor ions and/or reacceleration of product ions is not required. Thus, product ions produced by post-source processes (laser induced dissociation or LID, metastable decomposition and opportunistic collisions) are recorded in the product ion mass spectra at the same times as their isomass ions produced by collision induced dissociation (CID). In general both LID and CID product ion mass spectra are very similar, producing primarily b-series and y-series ions, though there is some preference for fragmentation at weaker bonds such as those at proline or aspartic acid residues. The tandem mass spectrometer has been used to determine the acetylation sites for a histone acetyl transferase (HAT) protein. A novel and improved method for derivatizing tryptic fragments by N-terminal sulfonation produces almost exclusively y-series ions, and has been used to determine protein ubiquitination. The tandem mass spectrometer has also been used to identify potential biomarkers associated with heart failure, in particular that fraction containing albumin that is generally removed from serum samples to permit protein biomarker analysis. Analysis of the unfractionated serum, the albuminome, and the depleted serum is also carried out using surface-enhanced laser desorption/ionization (SELDI) and the high molecular weight proteins are monitored by using a Comet macromizer™ TOF mass spectrometer with a very high mass cryocooled detector. PMID:20717501

  9. LLNL Tandem Mirror Experiment (TMX) upgrade vacuum system

    SciTech Connect

    Pickles, W.L.; Chargin, A.K.; Drake, R.P.

    1981-09-15

    TMX Upgrade is a large, tandem, magnetic-mirror fusion experiment with stringent requirements on base pressure (10/sup -8/ torr), low H reflux from the first walls, and peak gas pressure (5 x 10/sup -7/ torr) due to neutral beam gas during plasma operation. The 225 m/sup 3/ vacuum vessel is initially evacuated by turbopumps. Cryopumps provide a continuous sink for gases other than helium, deuterium, and hydrogen. The neutral beam system introduces up to 480 l/s of H or D. The hydrogen isotopes are pumped at very high speed by titanium sublimed onto two cylindrical radially separated stainless steel quilted liners with a total surface area of 540 m/sup 2/. These surfaces (when cooled to about 80/sup 0/K) provide a pumping speed of 6 x 10/sup 7/ l/s for hydrogen. The titanium getter system is programmable and is used for heating as well as gettering. The inner plasma liner can be operated at elevated temperatures to enhance migration of gases away from the surfaces close to the plasma. Glow discharge cleaning is part of the pumpdown procedure. The design features are discussed in conjunction with the operating procedures developed to manage the dynamic vacuum conditions.

  10. Negative deuterium ions for tandem mirror next step and tandem mirror reactors

    SciTech Connect

    Hamilton, G.W.

    1980-09-25

    Recent designs for mirror fusion reactors with good power balance include ambipolar potential plugs to reduce end losses and thermal barriers to maintain a difference in electron temperature between the large-volume central cell plasma and the confining end plugs. These designs led to several new requirements for D/sup 0/ neutral beams derived from negative ions at energies of 150 to 200 keV and possibly higher. Such beams are required for injection of fat ions into the plugs and the barrier and for charge-exchange pumping of thermal ions diffusing into the barrier. Negative ions are preferred for these purposes because of their relatively high efficiency of neutralization and their high purity of single-energy D/sup -/. Examples of injector designs for Tandem Mirror Next Step (TMNS) and Tandem Mirror Reactors (TMR) are presented.

  11. A new tandem mass spectrometer for photofragment spectroscopy of cold, gas-phase molecular ions

    SciTech Connect

    Svendsen, Annette; Lorenz, Ulrich J.; Boyarkin, Oleg V.; Rizzo, Thomas R.

    2010-07-15

    We present here the design of a new tandem mass spectrometer that combines an electrospray ion source with a cryogenically cooled ion trap for spectroscopic studies of cold, gas-phase ions. The ability to generate large ions in the gas phase without fragmentation, cool them to {approx}10 K in an ion trap, and perform photofragment spectroscopy opens up new possibilities for spectroscopic characterization of large biomolecular ions. The incorporation of an ion funnel, together with a number of small enhancements, significantly improves the sensitivity, signal stability, and ease of use compared with the previous instrument built in our laboratory.

  12. Magnetic alignment of the Tara tandem mirror

    NASA Astrophysics Data System (ADS)

    Post, R. S.; Coleman, J. W.; Irby, J. H.; Olmstead, M. M.; Torti, R. P.

    1985-06-01

    Techniques developed for the alignment of high-energy accelerators have been applied to the alignment of the Tara tandem mirror magnetic confinement device. Tools used were: a transit/laser surveyor's system for establishing an invariant reference; optical scattering from ferromagnetic crystallites for establishing magnetic centers in the quadrupole anchor/transition modules; an electron-optical circle-generating wand for alignment of the solenoidal plug and central cell modules; and four differently configured electron emissive probes, including a 40-beam flux mapping e gun, for testing the alignment of the coils under vacuum. Procedures are outlined, and results are given which show that the magnetic axes of the individual coils in the Tara set have been made colinear with each other and with the reference to within ±1.0 mm over the length of the machine between the anchor midplanes.

  13. Protein Sequencing with Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ziady, Assem G.; Kinter, Michael

    The recent introduction of electrospray ionization techniques that are suitable for peptides and whole proteins has allowed for the design of mass spectrometric protocols that provide accurate sequence information for proteins. The advantages gained by these approaches over traditional Edman Degradation sequencing include faster analysis and femtomole, sometimes attomole, sensitivity. The ability to efficiently identify proteins has allowed investigators to conduct studies on their differential expression or modification in response to various treatments or disease states. In this chapter, we discuss the use of electrospray tandem mass spectrometry, a technique whereby protein-derived peptides are subjected to fragmentation in the gas phase, revealing sequence information for the protein. This powerful technique has been instrumental for the study of proteins and markers associated with various disorders, including heart disease, cancer, and cystic fibrosis. We use the study of protein expression in cystic fibrosis as an example.

  14. Routine approach to qualitatively screen for 300 pesticides and quantify those frequently detected in fruits and vegetables using liquid chromatography tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes an efficient and effective analytical scheme to first screen for 300 pesticides in fruit and vegetables samples using liquid chromatography tandem mass spectrometry (LC-MS/MS) with a commercial enhanced product ion method. Then, the presumed positive extracts were analyzed using...

  15. Ultra-sensitive tandem colloidal quantum-dot photodetectors

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenyu; Hu, Wenjia; Mo, Chen; Liu, Yan; Zhang, Wenjun; You, Guanjun; Wang, Li; Atalla, Mahmoud R. M.; Zhang, Yu; Liu, Jie; Kurhade, Kandhar K.; Xu, Jian

    2015-10-01

    The solution-processed PbSe colloidal quantum-dot (CQD) infrared photodetector with tandem architecture is proposed to address the high dark current issue. The electrical transport mechanism in tandem has been fundamentally changed in which the recombination of carriers at an intermediate layer becomes dominant rather than carriers hopping between nearest neighbors in CQD materials. As a result, the tandem photodetector exhibits ultra-high detectivities of 4.7 × 1013 Jones and 8.1 × 1013 Jones under 34 ?W cm-2 illumination at 1100 nm, at 275 K and 100 K, respectively.

  16. Ultra-sensitive tandem colloidal quantum-dot photodetectors.

    PubMed

    Jiang, Zhenyu; Hu, Wenjia; Mo, Chen; Liu, Yan; Zhang, Wenjun; You, Guanjun; Wang, Li; Atalla, Mahmoud R M; Zhang, Yu; Liu, Jie; Kurhade, Kandhar K; Xu, Jian

    2015-10-21

    The solution-processed PbSe colloidal quantum-dot (CQD) infrared photodetector with tandem architecture is proposed to address the high dark current issue. The electrical transport mechanism in tandem has been fundamentally changed in which the recombination of carriers at an intermediate layer becomes dominant rather than carriers hopping between nearest neighbors in CQD materials. As a result, the tandem photodetector exhibits ultra-high detectivities of 4.7 × 10(13) Jones and 8.1 × 10(13) Jones under 34 ?W cm(-2) illumination at 1100 nm, at 275 K and 100 K, respectively. PMID:26388137

  17. Kinetically Stabilized Axisymmetric Tandem Mirrors: Summary of Studies

    SciTech Connect

    Post, R F

    2005-02-08

    The path to practical fusion power through plasma confinement in magnetic fields, if it is solely based on the present front-runner, the tokamak, is clearly long, expensive, and arduous. The root causes for this situation lie in the effects of endemic plasma turbulence and in the complexity the tokamak's ''closed'' field geometry. The studies carried out in the investigations described in the attached reports are aimed at finding an approach that does not suffer from these problems. This goal is to be achieved by employing an axisymmetric ''open'' magnetic field geometry, i.e. one generated by a linear array of circular magnet coils, and employing the magnetic mirror effect in accomplishing the plugging of end leakage. More specifically, the studies were aimed at utilizing the tandem-mirror concept in an axisymmetric configuration to achieve performance superior to the tokamak, and in a far simpler system, one for which the cost and development time could be much lower than that for the tokamak, as exemplified by ITER and its follow-ons. An important stimulus for investigating axisymmetric versions of the tandem mirror is the fact that, beginning from early days in fusion research there have been examples of axisymmetric mirror experiments where the plasma exhibited crossfield transport far below the turbulence-enhanced rates characteristic of tokamaks, in specific cases approaching the ''classical'' rate. From the standpoint of theory, axisymmetric mirror-based systems have special characteristics that help explain the low levels of turbulence that have been observed. Among these are the facts that there are no parallel currents in the equilibrium state, and that the drift surfaces of all of the trapped particles are closed surfaces, as shown early on by Teller and Northrop. In addition, in such systems it is possible to arrange that the radial boundary of the confined plasma terminates without contact with the chamber wall. This possibility reduces the probability of so-called ''temperature-gradient'' instabilities, known to be endemic to closed systems. Finally, the open-ended nature of the field readily allows the control of the radial potential distribution, a circumstance that has been shown, for example in the Gamma 10 tandem-mirror experiment at Tsukuba Japan, to suppress drift-type instability modes. Standing against all of these attractive properties of axisymmetric mirror-based systems is the fact, shown early on, that such systems are prone to MHD ''interchange'' instabilities, one in which the plasma column drifts transversely, at a rate far above classical transport. Observed early on, the ''cure'' that was universally adopted, as first demonstrated in the famous ''Ioffe experiment'', was to abandon axisymmetry and employ so-called ''magnetic-well'' fields, ones in which the field increases radially and axially from its interior, strongly suppressing the MHD interchange mode, up to plasma ''beta'' values approaching unity, observed in the 2X2B experiment. When the tandem mirror concept was introduced in 1976 every experiment that was constructed employed various combinations of non-axisymmetric coil configurations (''Baseball,'' and ''Yin-Yang'' coils) to create the magnetic fields. But it came at a heavy price: non-axisymmetric fields gave rise to new non-classical loss channels, and the complexity of the fields introduced difficult engineering problems. It was well recognized at the time that it would be highly advantageous to preserve axisymmetry of the tandem mirror coils, but there was no apparent way to stabilize the ubiquitous MHD interchange mode. A decade later a way to accomplish this end was analyzed theoretically, and, a few years later successfully demonstrated experimentally, in the Gas Dynamic Trap (GDT) experiment at Novosibirsk. The concept: the presence of a sufficient amount of plasma on the expanding field lines outside the end mirrors of a mirror machine can act as an ''anchor,'' MHD stabilizing the interior, confined, plasma. Moreover, Ryutov's theory showed that the pressure of this a

  18. TACHYON: Tandem Execution for Efficient Live Patch Testing Matthew Maurer

    E-print Network

    Brumley, David

    TACHYON: Tandem Execution for Efficient Live Patch Testing Matthew Maurer maurer@cmu.edu Carnegie in TACHYON, a system for online patch testing in Linux. TACHYON is able to automatically check and verify

  19. Tandem isomerization/telomerization of long chain dienes

    E-print Network

    Torrente-Murciano, Laura; Nielsen, David J.; Cavell, Kingsley\tJ.; Lapkin, Alexei A.

    2014-06-13

    The ?rst example of a tandem reaction involving double-bond migration in combination with telomerization is reported. Homogeneous and heterogeneous Ru catalysts were employed as isomerization catalysts, and telomerization was realized using a...

  20. Tandem wheel drop-legs for standard truck trailer

    NASA Technical Reports Server (NTRS)

    Cantwell, W.; Selstad, R.

    1970-01-01

    Tandem wheel drop-leg device provides a semitrailer with fore and aft mobility that allows it to be moved without a prime mover. The modified drop-legs have trunnion dual wheels and an adjustable brace.

  1. Design of tandem mirror reactors with thermal barriers

    SciTech Connect

    Carlson, G.A.

    1980-01-01

    End-plug technologies for tandem mirror reactors include high-field superconducting magnets, neutral beam injectors, and gyrotrons for electron cyclotron resonant heating (ECRH). In addition to their normal use for sustenance of the end-plug plasmas, neutral beam injectors are used for ''pumping'' trapped ions from the thermal barrier regions by charge exchange. An extra function of the axially directed pump beams is the removal of thermalized alpha particles from the reactor. The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror fusion Test Facility (MFTF-B) in 1984.

  2. Plasma-wall interactions in tandem mirror machines

    SciTech Connect

    Allen, S.L.

    1984-11-01

    A description is presented of the plasma-surface interactions in thermal-barrier tandem-mirror machines. The thermal-barrier mode of axial confinement is an integral part of a tandem mirror, and it dictates the required plasma conditions, particularly at the surface of the plasma. For this reason, a qualitative discussion of the thermal barrier is presented first in Section 2. A brief description of the experimental configuration used in tandem mirrors to create the thermal barrier is then examined in detail in Section 3; the TMX-U and MFTF-B machines are used as specific examples. In Section 4, the relevant plasma-surface interaction issues are addressed, and experimental results from currently operating tandom mirror machines are included. Section 5 is both a summary and a discussion of future work concerned with plasma-surface interactions in tandem mirrors.

  3. Solar-to-Chemical Energy Conversion with Photoelectrochemical Tandem Cells.

    PubMed

    Sivula, Kevin

    2013-01-01

    Efficiently and inexpensively converting solar energy into chemical fuels is an important goal towards a sustainable energy economy. An integrated tandem cell approach could reasonably convert over 20% of the sun's energy directly into chemical fuels like H2 via water splitting. Many different systems have been investigated using various combinations of photovoltaic cells and photoelectrodes, but in order to be economically competitive with the production of H2 from fossil fuels, a practical water splitting tandem cell must optimize cost, longevity and performance. In this short review, the practical aspects of solar fuel production are considered from the perspective of a semiconductor-based tandem cell and the latest advances with a very promising technology - metal oxide photoelectrochemical tandem cells - are presented. PMID:23574955

  4. The Bucharest Tandem Accelerator - part of the European Infrastructure

    SciTech Connect

    Zamfir, Nicolae Victor

    2007-04-23

    The Bucharest Tandem van de Graaff accelerator in Bucharest is described. The scientific program in both applied and basic research is outlined. Through many international collaborations, the accelerator is, indeed, part of the European Nuclear Physics Research infrastructure.

  5. Short tandem repeat (STR) profile authentication via machine learning techniques

    E-print Network

    Shcherbina, Anna

    2012-01-01

    Short tandem repeat (STR) DNA profiles have multiple uses in forensic analysis, kinship identification, and human biometrics. However, as biotechnology progresses, there is a growing concern that STR profiles can be created ...

  6. D STAND DELIVERY END OF #44 TANDEM BREAKDOWN MILL WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    D STAND DELIVERY END OF #44 TANDEM BREAKDOWN MILL WITH UPCOILER. BACKUP ROLLS, 40 TONS. WORK ROLLS, 20 TONS., C. 1900. OPERATING SPEED, 600'/MINUTE. AUTOMATIC GAUGE CONTROL. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  7. Tandem shock waves in medicine and biology: a review of potential applications and successes

    NASA Astrophysics Data System (ADS)

    Lukes, P.; Fernández, F.; Gutiérrez-Aceves, J.; Fernández, E.; Alvarez, U. M.; Sunka, P.; Loske, A. M.

    2015-07-01

    Shock waves have been established as a safe and effective treatment for a wide range of diseases. Research groups worldwide are working on improving shock wave technology and developing new applications of shock waves to medicine and biology. The passage of a shock wave through soft tissue, fluids, and suspensions containing cells may result in acoustic cavitation i.e., the expansion and violent collapse of microbubbles, which generates secondary shock waves and the emission of microjets of fluid. Cavitation has been recognized as a significant phenomenon that produces both desirable and undesirable biomedical effects. Several studies have shown that cavitation can be controlled by emitting two shock waves that can be delayed by tenths or hundreds of microseconds. These dual-pulse pressure pulses, which are known as tandem shock waves, have been shown to enhance in vitro and in vivo urinary stone fragmentation, cause significant cytotoxic effects in tumor cells, delay tumor growth, enhance the bactericidal effect of shock waves and significantly increase the efficiency of genetic transformations in bacteria and fungi. This article provides an overview of the basic physical principles, methodologies, achievements and potential uses of tandem shock waves to improve biomedical applications.

  8. Global design optimization for an axial-flow tandem pump based on surrogate method

    NASA Astrophysics Data System (ADS)

    Li, D. H.; Zhao, Y.; Y Wang, G.

    2013-12-01

    Tandem pump, compared with multistage pump, goes without guide vanes between impellers. Better cavitation performance and significant reduction of the axial geometry scale is important for high-speed propulsion. This study presents a global design optimization method based on surrogated method for an axial-flow tandem pump to enhance trade-off performances: energy and cavitation performances. At the same time, interactions between impellers and impacts on the performances are analyzed. Fixed angle of blades in impellers and phase angle are performed as design variables. Efficiency and minimum average pressure coefficient (MAPC) on axial sectional surface in front impeller are the objective function, which can represent energy and cavitation performances well. Different surrogate models are constructed, and Global Sensitivity Analysis and Pareto Front method are used. The results show that, 1) Influence from phase angle on performances can be neglected compared with other two design variables, 2) Impact ratio of fixed angle of blades in two impellers on efficiency are the same as their designed loading distributions, which is 4:6, 3) The optimization results can enhance the trade-off performances well: efficiency is improved by 0.6%, and the MAPC is improved by 4.5%.

  9. Light Signaling Mechanism of Two Tandem Bacteriophytochromes.

    PubMed

    Yang, Xiaojing; Stojkovi?, Emina A; Ozarowski, Wesley B; Kuk, Jane; Davydova, Erna; Moffat, Keith

    2015-07-01

    RpBphP2 and RpBphP3, two tandem bacteriophytochromes from the photosynthetic bacterium Rhodopseudomonas palustris, share high sequence identity but exhibit distinct photoconversion behavior. Unlike the canonical RpBphP2, RpBphP3 photoconverts to an unusual near-red-absorbing (Pnr) state; both are required for synthesis of light-harvesting complexes under low-light conditions. Here we report the crystal structures of the photosensory core modules of RpBphP2 and RpBphP3. Despite different quaternary structures, RpBphP2 and RpBphP3 adopt nearly identical tertiary structures. The RpBphP3 structure reveals tongue-and-groove interactions at the interface between the GAF and PHY domains. A single mutation in the PRxSF motif at the GAF-PHY interface abolishes light-induced formation of the Pnr state in RpBphP3, possibly due to altered structural rigidity of the chromophore-binding pocket. Structural comparisons suggest that long-range signaling involves structural rearrangement of the helical spine at the dimer interface. These structures, together with mutational studies, provide insights into photoconversion and the long-range signaling mechanism in phytochromes. PMID:26095026

  10. Landmarks and ant search strategies after interrupted tandem runs.

    PubMed

    Basari, Norasmah; Bruendl, Aisha C; Hemingway, Charlotte E; Roberts, Nicholas W; Sendova-Franks, Ana B; Franks, Nigel R

    2014-03-15

    During a tandem run, a single leading ant recruits a single follower to an important resource such as a new nest. To examine this process, we used a motorized gantry, which has not previously been used in ant studies, to track tandem running ants accurately in a large arena and we compared their performance in the presence of different types of landmark. We interrupted tandem runs by taking away the leader and moved a large distant landmark behind the new nest just at the time of this separation. Our aim was to determine what information followers might have obtained from the incomplete tandem run they had followed, and how they behaved after the tandem run had been interrupted. Our results show that former followers search by using composite random strategies with elements of sub-diffusive and diffusive movements. Furthermore, when we provided more landmarks former followers searched for longer. However, when all landmarks were removed completely from the arena, the ants' search duration lasted up to four times longer. Hence, their search strategy changes in the presence or absence of landmarks. Even after extensive search of this kind, former followers headed back to their old nest but did not return along the path of the tandem run they had followed. The combination of the position to which the large distant landmark behind the new nest was moved and the presence or absence of additional landmarks influenced the orientation of the former followers' paths back to the old nest. We also found that these ants exhibit behavioural lateralization in which they possibly use their right eye more than their left eye to recognize landmarks for navigation. Our results suggest that former follower ants learn landmarks during tandem running and use this information to make strategic decisions. PMID:24198259

  11. Hot-electron plasma formation and confinement in the tandem mirror experiment-upgrade

    SciTech Connect

    Ress, D.B.

    1988-06-01

    The tandem mirror experiment-upgrade (TMX-U) at the Lawrence Livermore National Laboratory (LLNL) is the first experiment to investigate the thermal-barrier tandem-mirror concept. One attractive feature of the tandem magnetic mirror as a commercial power reactor is that the fusion reactions occur in an easily accessible center-cell. On the other hand, complicated end-cells are necessary to provide magnetohydrodynamic (MHD) stability and improved particle confinement of the center-cell plasma. In these end-cells, enhanced confinement is achieved with a particular axial potential profile that is formed with electron-cyclotron range-of-frequency heating (ECRF heating, ECRH). By modifying the loss rates of electrons at spatially distinct locations within the end-cells, the ECRH can tailor the plasma potential profile in the desired fashion. Specifically, the thermal-barrier concept requires generation of a population of energetic electrons near the midplane of each end-cell. To be effective, the transverse (to the magnetic field) spatial structure of the hot-electron plasma must be fairly uniform. In this dissertation we characterize the spatial structure of the ECRH-generated plasma, and determine how the structure builds up in time. Furthermore, the plasma should efficiently absorb the ECRF power, and a large fraction of the electrons must be well confined near the end-cell midplane. Therefore, we also examine in detail the ECRH power balance, determining how the ECRF power is absorbed by the plasma, and the processes through which that power is confined and lost. 43 refs., 69 figs., 6 tabs.

  12. Dynamic analysis of FPSO with a tandem offloading system

    SciTech Connect

    Nishimoto, K.; Brinati, H.L.; Fucatu, C.H.

    1996-12-31

    Turret-moored tankers have been conceived by the oil industry as a Floating Production Storage and Offloading system (FPSO). The oil stored in ship hull may be offloaded by a shuttle ship connected to the FPSO by a hawser, in a so called tandem system configuration. The problem of dynamic instability, that arises with other ship mooring systems, like single point mooring and spread mooring systems subjected to the environment forces, may also be present with the tandem system. The present paper is concerned with the dynamic analysis of the tandem system. It is an extension of the research that the authors had carried out with the application of a new mathematical model to deal with the SPM dynamics. This formulation is a manoeuvering model specially developed to represent low speed ship motion. Initially presented is the mathematical model that represents the dynamics of the tandem system. Particular emphasis is given to the description of the slow ship dynamics for the two vessels. Simulation of the mathematical model is used to analyze the dynamical behavior of the tandem system. The effects of hawser length, wind and current speeds and wave angle of incidence are investigated.

  13. Numerical simulations of the current-matching effect and operation mechanisms on the performance of InGaN/Si tandem cells

    PubMed Central

    2014-01-01

    Numerical simulations are conducted to study the current-matching effect and operation mechanisms in and to design the optimized device structure of InGaN/Si tandem cells. The characteristics of short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and conversion efficiency (?) of InGaN/Si tandem cells are determined by the current-matching effect. The similar trend of ? to that of Jsc shows that Jsc is a dominant factor in determining the performance of InGaN/Si tandem cells. In addition, the combined effects of the Jsc, Voc, and FF lead to an optimized ? in the medium-indium, xpn-InGaNInGaN?to?Si, InGaN/Si tandem cell. At xpn-InGaNInGaN?to?Si, the Jsc of the InGaN subcell is equal to that of the Si subcell such that an InGaN/Si tandem cell reaches the current matching condition to operate at the maximum power point. Similar to the Jsc and FF, the ? for low- xpn-InGaNxpn-InGaNInGaN?to?Si InGaN/Si tandem cells are InGaN- and Si subcell-limited, respectively. Furthermore, the p- and n-layer thicknesses, indium content, and position of depletion region of InGaN subcell should be adjusted to reapportion the light between the two subcells and to achieve the maximum conversion efficiency. With appropriate thicknesses of p- and n-InGaN, In0.5–0.6Ga0.5–0.4?N/Si tandem cells can exhibit as high as approximately 34% to 36.5% conversion efficiency, demonstrating that a medium-indium InGaN/Si tandem cell results in a high-efficiency solar cell. Simulation results determine that the current-matching effect and operation mechanisms of InGaN/Si tandem cells can be utilized for efficiency enhancement through the optimized device structures. PMID:25520599

  14. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

  15. UPGRADE AND OPERATION OF THE BNL TANDEMS FOR RHIC INJECTION.

    SciTech Connect

    STESKI,D.B.; ALESSI,J.; BENJAMIN,J.; CARLSON,C.; MANNI,M.; THIEBERGER,P.; WIPLICH,M.

    2001-06-18

    One of the tandem Van de Graaffs (MP7) at Brookhaven National Laboratory (BNL) has successfully completed its first year as an injector for the Relativistic Heavy Ion Collider (RHIC). The tandem provided pulsed beam of Au{sup +32} (peak intensity 80 e{mu}A, 500{micro}s) with only 17 hours of downtime during a 5 month run. Improvements are being made to further increase the intensity of the gold beam for the experimental run starting in 2001. A second tandem Van de Graaff (MP6) has been extensively upgraded and can now reach a terminal voltage of over 14MV. A beamline has been constructed to transport the MP6 beam around MP7 and then connect to the existing MP7 beamlines. This has allowed MP6 to deliver beam to local target rooms for an outside user program, while MP7 has simultaneously injected RHIC. MP6 can also be used as an injector for RHIC.

  16. Dosimetric Comparison of Tandem and Ovoids vs. Tandem and Ring for Intracavitary Gynecologic Applications

    SciTech Connect

    Levin, Daphne Menhel, Janna; Rabin, Tanya; Pfeffer, M. Raphael; Symon, Zvi

    2008-01-01

    We evaluated dosimetric differences in tandem and ovoid (TO) and tandem and ring (TR) gynecologic brachytherapy applicators. Seventeen patients with cervical cancer (Stages II-IV) receiving 3 high-dose-rate (HDR) brachytherapy applications (both TO and TR) were studied. Patients underwent computed tomography (CT) scans with contrast in bladder, and were prescribed 8 Gy to ICRU points A, with additional optimization goals of maintaining the pear-shaped dose distribution and minimizing bladder and rectum doses. Bladder and rectum point doses, mean, and maximum doses were calculated. Total treatment time and volumes treated to 95%, 85%, 50%, and 20% or the prescription dose were compared. There were no significant differences between TO and TR applicators in doses to prescription points or critical organs. However, there were significant differences (p < 0.001) between the applicators in treated volumes and total treatment time. The TO treated larger volumes over a longer time. Within each patient, when the applicators were compared, treated volumes were also found to be significantly different (p < 0.01, {chi}{sup 2}). Our results demonstrate that the 2 applicators, while delivering the prescribed dose to points A and keeping critical organ doses below tolerance, treat significantly different volumes. It is unclear if this difference is clinically meaningful. TO applicators may be treating surrounding healthy tissue unnecessarily, or TR applicators may be underdosing tumor tissue. Further investigation with appropriate imaging modalities is required for accurate delineation of target volumes. Clearly, the TO and TR are not identical, and should not be used interchangeably without further study.

  17. Counter-Rotating Tandem Motor Drilling System

    SciTech Connect

    Kent Perry

    2009-04-30

    Gas Technology Institute (GTI), in partnership with Dennis Tool Company (DTC), has worked to develop an advanced drill bit system to be used with microhole drilling assemblies. One of the main objectives of this project was to utilize new and existing coiled tubing and slimhole drilling technologies to develop Microhole Technology (MHT) so as to make significant reductions in the cost of E&P down to 5000 feet in wellbores as small as 3.5 inches in diameter. This new technology was developed to work toward the DOE's goal of enabling domestic shallow oil and gas wells to be drilled inexpensively compared to wells drilled utilizing conventional drilling practices. Overall drilling costs can be lowered by drilling a well as quickly as possible. For this reason, a high drilling rate of penetration is always desired. In general, high drilling rates of penetration (ROP) can be achieved by increasing the weight on bit and increasing the rotary speed of the bit. As the weight on bit is increased, the cutting inserts penetrate deeper into the rock, resulting in a deeper depth of cut. As the depth of cut increases, the amount of torque required to turn the bit also increases. The Counter-Rotating Tandem Motor Drilling System (CRTMDS) was planned to achieve high rate of penetration (ROP) resulting in the reduction of the drilling cost. The system includes two counter-rotating cutter systems to reduce or eliminate the reactive torque the drillpipe or coiled tubing must resist. This would allow the application of maximum weight-on-bit and rotational velocities that a coiled tubing drilling unit is capable of delivering. Several variations of the CRTDMS were designed, manufactured and tested. The original tests failed leading to design modifications. Two versions of the modified system were tested and showed that the concept is both positive and practical; however, the tests showed that for the system to be robust and durable, borehole diameter should be substantially larger than that of slim holes. As a result, the research team decided to complete the project, document the tested designs and seek further support for the concept outside of the DOE.

  18. The innervation of tandem muscle spindles in the cat neck.

    PubMed

    Richmond, F J; Bakker, G J; Bakker, D A; Stacey, M J

    1986-03-22

    Patterns of innervation were examined in tandem muscle spindles teased from silver-stained muscles of the cat neck. Each tandem spindle was composed of two or more encapsulated receptors linked in series by a shared bag2 fiber. In most tandem spindles, two different types of encapsulation were identified according to differences in their intrafusal fiber content. One type, the b1b2c unit, contained typical bag1, bag2, and chain fibers and was structurally similar to single spindles described in other cat muscles. Each b1b2c unit contained a single primary sensory ending and 1-6 secondary endings. Fusimotor innervation was supplied by many axons. Some fusimotor axons ended in trail ramifications on bag2 and chain fibers, others ended in plates on the bag1 or long chain fiber. The other type of tandem encapsulation, the b2c unit, had only bag2 and chain fibers in its intrafusal fiber bundle. The b2c unit was usually supplied by only one sensory axon that ended on the nucleated part of the intrafusal fiber bundle. This single ending had a more variable terminal morphology than the primary ending in b1b2c units. A few b2c units (3/49) were also supplied by a secondary ending. The fusimotor innervation of the b2c unit was relatively simple. A single pole of the b2c unit was usually supplied by only one to three axons, all ending in trail ramifications. No plate endings were found in b2c units. These morphological specializations suggest that b1b2c and b2c units in tandem spindles differ in both their transductive and fusimotor mechanisms. Thus, the tandem spindle is a specialized structure that may provide additional proprioceptive information beyond that available from single muscle spindles. PMID:2422225

  19. Performance predictions for monolithic, thin-film CdTe/Ge tandem solar cells

    E-print Network

    Pulfrey, David L.

    Performance predictions for monolithic, thin-film CdTe/Ge tandem solar cells D.L. Pulfrey*, J. Dell on this by adding a thin-film germanium cell in a monolithic, tandem arrangement. Here we report on simulations

  20. Protein Complexes Characterization in Arabidopsis thaliana by Tandem Affinity Purification Coupled

    E-print Network

    Hirt, Heribert

    237 Chapter 18 Protein Complexes Characterization in Arabidopsis thaliana by Tandem Affinity the proteins involved in protein complexes in Arabidopsis thaliana and decipher some mechanisms of regulation in vivo protein complexes. Key words Arabidopsis thaliana, Protein complexes, Tandem affinity purification

  1. Rules of Stereoselectivity in Tandem Oxidative Polycyclization Reaction with Rhenium(VII) Oxides

    E-print Network

    Keinan, Ehud

    Rules of Stereoselectivity in Tandem Oxidative Polycyclization Reaction with Rhenium(VII) Oxides, Israel ReceiVed April 17, 1998 The tandem oxidative polycyclization reaction with rhenium- (VII) reagents

  2. Tandem riboswitch architectures exhibit complex gene control functions.

    PubMed

    Sudarsan, Narasimhan; Hammond, Ming C; Block, Kirsten F; Welz, Rüdiger; Barrick, Jeffrey E; Roth, Adam; Breaker, Ronald R

    2006-10-13

    Riboswitches are structured RNAs typically located in the 5' untranslated regions of bacterial mRNAs that bind metabolites and control gene expression. Most riboswitches sense one metabolite and function as simple genetic switches. However, we found that the 5' region of the Bacillus clausii metE messenger RNA includes two riboswitches that respond to S-adenosylmethionine and coenzyme B12. This tandem arrangement yields a composite gene control system that functions as a two-input Boolean NOR logic gate. These findings and the discovery of additional tandem riboswitch architectures reveal how simple RNA elements can be assembled to make sophisticated genetic decisions without involving protein factors. PMID:17038623

  3. Summary of the MARS tandem-mirror reactor design

    SciTech Connect

    Logan, B.G.

    1983-09-01

    A recently completed two-year study of a commercial tandem-mirror reactor design (Mirror Advanced Reactor Study (MARS)) is briefly reviewed. The end plugs are designed for trapped-particle stability, MHD ballooning, balanced geodesic curvature, and small radial electric fields in the central cell. New technologies such as lithium-lead blankets, 24 T hybrid coils, gridless direct converters and plasma halo vacuum pumps are highlighted. General characteristics of the MARS tandem mirror and STARFIRE tokamak reactor design are compared. A design of an upgrade of MFTF-B incorporating many of the MARS features is discussed.

  4. Tandem junction amorphous semiconductor photovoltaic cell

    DOEpatents

    Dalal, Vikram L. (Newark, DE)

    1983-01-01

    A photovoltaic stack comprising at least two p.sup.+ i n.sup.+ cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p.sup.+ i n.sup.+ cells.

  5. Tandem junction amorphous semiconductor photovoltaic cell

    DOEpatents

    Dalal, V.L.

    1983-06-07

    A photovoltaic stack comprising at least two p[sup +]i n[sup +] cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p[sup +]i n[sup +] cells. 3 figs.

  6. Pedagogical Design of an eTandem Chinese-French Writing Course

    E-print Network

    Pedagogical Design of an eTandem Chinese-French Writing Course Jue Wang (ESTAS, Faculty of Arts/China and French/Switzerland. The eTandem Chinese-French writing course included theme-based oral communication and learning, tandem language learning, telecollaboration, intercultural competence, peer-to-peer correction

  7. High efficiency GaAs/Ge monolithic tandem solar cells

    NASA Technical Reports Server (NTRS)

    Tobin, S. P.; Vernon, S. M.; Bajgar, C.; Haven, V. E.; Geoffroy, L. M.; Sanfacon, M. M.; Lillington, D. R.; Hart, R. E., Jr.

    1988-01-01

    Two-terminal monolithic tandem cells consisting of a GaAs solar cell grown epitaxially on a Ge solar cell substrate are very attractive for space applications. Tandem cells of GaAs grown by metal-organic chemical vapor deposition on thin Ge were investigated to address both higher efficiency and reduced weight. Two materials growth issues associated with this heteroepitaxial system, autodoping of the GaAs layers by Ge and diffusion of Ga and As into the Ge substrate, were addressed. The latter appears to result in information of an unintentional p-n junction in the Ge. Early simulator measurements gave efficiencies as high as 21.7 percent for 4 cm2 GaAs/Ge cells, but recent high-altitude testing has given efficiencies of 18 percent. Sources of errors in simulator measurements of two-terminal tandem cells are discussed. A limiting efficiency of about 36 percent for the tandem cell at AMO was calculated. Ways to improve the performance of present cells, primarily by increasing the Isc and Voc of the Ge cell, are proposed.

  8. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    14 Aeronautics and Space 1 2011-01-01 2011-01-01...23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard...configurations. The forward structure of a canard or tandem...

  9. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    14 Aeronautics and Space 1 2010-01-01 2010-01-01...23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard...configurations. The forward structure of a canard or tandem...

  10. Texture Synthesis with Tandem Genetic Algorithms using Nonparametric Partially

    E-print Network

    Ashlock, Dan

    ordered Markov model for the exam- ple texture. The genetic algorithms used are themselves are quiteTexture Synthesis with Tandem Genetic Algorithms using Nonparametric Partially Ordered Markov textures. We use a pair of genetic algorithms to cre- ate fast one-pass generating algorithms for five

  11. TassDB: a database of alternative tandem splice sites

    E-print Network

    Will, Sebastian

    , Ernst-Abbe-Platz 2, 07743 Jena, Germany, 2 Genome Analysis, Leibniz Institute for Age Research. This database should facilitate further experimental studies and large-scale bioinformatics analyses of tandem important processes such as the formation and function of synapses (4), axon guidance in Drosophila (5

  12. Vacuum insulation tandem accelerator for B. Bayanov1

    E-print Network

    Taskaev, Sergey Yur'evich

    of Nuclear Physics, Novosibirsk, Russia 2 Institute of Physics and Power Engineering, Obninsk, Russia 3, as a powerful source of high voltage. Negative hydrogen ion beam is injected into electrostatic tandem of high current hydrogen negative ions by special geometry of potential electrodes with vacuum insulation

  13. Production of Arq+ ions with a tandem linear Paul trap

    NASA Astrophysics Data System (ADS)

    Higaki, H.; Nagayasu, K.; Iwai, T.; Ito, K.; Okamoto, H.

    2015-06-01

    A tandem linear Paul trap was used to create highly charged Argon ions by electron impact ionizations. By improving the operation scheme, the production of Ar4+ ions was confirmed. Possible improvements for the future experiments with laser cooled Ca+ ions are suggested.

  14. Bio-olefins from unsaturated fatty acids via tandem catalysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new catalytic route to bio-olefins from unsaturated fatty acids will be described. At the heart of the process, the catalyst apparently functions in a tandem mode by both dynamically isomerizing the positions of double bonds in an aliphatic chain and, subsequently, decarboxylating specific isomers...

  15. High power tandem-pumped thulium-doped fiber laser.

    PubMed

    Wang, Yao; Yang, Jianlong; Huang, Chongyuan; Luo, Yongfeng; Wang, Shiwei; Tang, Yulong; Xu, Jianqiu

    2015-02-01

    We propose a cascaded tandem pumping technique and show its high power and high efficient operation in the 2-?m wavelength region, opening up a new way to scale the output power of the 2-?m fiber laser to new levels (e.g. 10 kW). Using a 1942 nm Tm(3+) fiber laser as the pump source with the co- (counter-) propagating configuration, the 2020 nm Tm(3+) fiber laser generates 34.68 W (35.15W) of output power with 84.4% (86.3%) optical-to-optical efficiency and 91.7% (92.4%) slope efficiency, with respect to launched pump power. It provides the highest slope efficiency reported for 2-?m Tm(3+)-doped fiber lasers, and the highest output power for all-fiber tandem-pumped 2-?m fiber oscillators. This system fulfills the complete structure of the proposed cascaded tandem pumping technique in the 2-?m wavelength region (~1900 nm ? ~1940 nm ? ~2020 nm). Numerical analysis is also carried out to show the power scaling capability and efficiency of the cascaded tandem pumping technique. PMID:25836159

  16. Auto-Tandem Palladium Catalysis: From Isoxazole to 2-Azafluorenone.

    PubMed

    Das, Sajal; Hong, Dongsub; Chen, Zhiwei; She, Zhigang; Hersh, William H; Subramaniam, Gopal; Chen, Yu

    2015-11-20

    An auto-tandem palladium catalysis from halogen-substituted isoxazoles and Michael acceptors is described. It involves two mechanistically distinct palladium-catalyzed reactions, a Heck reaction and a rearrangement, leading to 2-azafluorenones. It is the first example of palladium-catalyzed ring opening of isoxazoles and rearrangement of the ?-imino ketone ring-opening product. PMID:26567443

  17. Peptide Retention Time Prediction Yields Improved Tandem Mass Spectrum Identification

    E-print Network

    Noble, William Stafford

    %, with the largest increase for non-specific cleavage with elastase. Keywords: Mass spectrometry, proteomics, peptide is shotgun proteomics using liquid chromatography and tandem mass spectrometry (LC-MS/MS)1 (McCormack et al, and thus the identity of the original proteins, can be automatically deduced by a database search algorithm

  18. Decision treedriven tandem mass spectrometry for shotgun proteomics

    E-print Network

    Cai, Long

    -scale protein sequencing. Tandem mass spectrometry, the process of peptide ion dissociation followed by mass efforts use enzymatic digestion of complex protein mixtures to generate samples contain- ing thousands of peptides1­3. The resultant mixtures are rich in chemical diversity as the peptides vary in length, post

  19. Robust Decentralized Detection and Social Learning in Tandem Networks

    NASA Astrophysics Data System (ADS)

    Ho, Jack; Tay, Wee Peng; Quek, Tony Q. S.; Chong, Edwin K. P.

    2015-10-01

    We study a tandem of agents who make decisions about an underlying binary hypothesis, where the distribution of the agent observations under each hypothesis comes from an uncertainty class. We investigate both decentralized detection rules, where agents collaborate to minimize the error probability of the final agent, and social learning rules, where each agent minimizes its own local minimax error probability. We then extend our results to the infinite tandem network, and derive necessary and sufficient conditions on the uncertainty classes for the minimax error probability to converge to zero when agents know their positions in the tandem. On the other hand, when agents do not know their positions in the network, we study the cases where agents collaborate to minimize the asymptotic minimax error probability, and where agents seek to minimize their worst-case minimax error probability (over all possible positions in the tandem). We show that asymptotic learning of the true hypothesis is no longer possible in these cases, and derive characterizations for the minimax error performance.

  20. Tandem Fan Applications in Advanced STOVL Fighter Configurations

    NASA Technical Reports Server (NTRS)

    Zola, Charlse L.; Wilson, Samuel B., III; Eskey, Megan A.

    1984-01-01

    The series/parallel tandem fan engine is evaluated for application in advanced STOVL supersonic fighter aircraft. Options in engine cycle parameters and design of the front fan flow diverter are examined for their effects on engine weight, dimensions, and other factors in integration of the engine with the aircraft. Operation of the engine in high-bypass flow mode during cruise and loiter flight is considered as a means of minimizizng fuel consumption. Engine thrust augmentation by burning in the front fan exhaust is discussed. Achievement of very sort takeoff with vectored thrust in briefly reviewed for tandem fan engine configurations with vectorable front fan nozzles. Examples are given of two aircraft configuration planforms, a delta-canard, and a forward-swept wing, to illustrate the major features. design considerations, and potential performance of the tandem fan installation in each. Full realization of the advantages of tandem fan propulsion are found to depend on careful selection of the aircraft configuration, since integration requirements can strongly influence the engine performance.

  1. Dynamics of tandem bubble interaction in a microfluidic channel

    PubMed Central

    Yuan, Fang; Sankin, Georgy; Zhong, Pei

    2011-01-01

    The dynamics of tandem bubble interaction in a microfluidic channel (800?×?21 ?m, W?×?H) have been investigated using high-speed photography, with resultant fluid motion characterized by particle imaging velocimetry. A single or tandem bubble is produced reliably via laser absorption by micron-sized gold dots (6 ?m in diameter with 40 ?m in separation distance) coated on a glass surface of the microfluidic channel. Using two pulsed Nd:YAG lasers at ??=?1064 nm and ?10 ?J/pulse, the dynamics of tandem bubble interaction (individual maximum bubble diameter of 50 ?m with a corresponding collapse time of 5.7 ?s) are examined at different phase delays. In close proximity (i.e., interbubble distance?=?40 ?m or ??=?0.8), the tandem bubbles interact strongly with each other, leading to asymmetric deformation of the bubble walls and jet formation, as well as the production of two pairs of vortices in the surrounding fluid rotating in opposite directions. The direction and speed of the jet (up to 95 m/s), as well as the orientation and strength of the vortices can be varied by adjusting the phase delay. PMID:22088007

  2. An investigation of the tyrothricin complex by tandem mass spectrometry

    NASA Astrophysics Data System (ADS)

    Barber, M.; Bell, D. J.; Morris, M. R.; Tetler, L. W.; Monaghan, J. J.; Morden, W. E.; Bycroft, B. W.; Green, B. N.

    1992-12-01

    Tandem mass spectrometry has been shown to be a powerful technique for determining the structures of biological compounds. This paper details the mass spectrometric methods employed to characterise the structural variations found within a mixture of cyclic decapeptides, tyrothricin, produced by the bacterium Bacillus brevis.

  3. CHARACTERIZATION OF INTEGRINS AND ASSOCIATED PROTEINS USING MALDI TANDEM MASS

    E-print Network

    Ens, Werner

    CHARACTERIZATION OF INTEGRINS AND ASSOCIATED PROTEINS USING MALDI TANDEM MASS SPECTROMETRY IGOR not function in isolation, but rather are essential components of dynamic supramolecular complexes, the associated proteins found in the complexes differ, resulting in the initiation of unique signal transduction

  4. Transport of a high brightness proton beam through the Munich tandem accelerator

    NASA Astrophysics Data System (ADS)

    Moser, M.; Greubel, C.; Carli, W.; Peeper, K.; Reichart, P.; Urban, B.; Vallentin, T.; Dollinger, G.

    2015-04-01

    Basic requirement for ion microprobes with sub-?m beam focus is a high brightness beam to fill the small phase space usually accepted by the ion microprobe with enough ion current for the desired application. We performed beam transport simulations to optimize beam brightness transported through the Munich tandem accelerator. This was done under the constraint of a maximum ion current of 10 ?A that is allowed to be injected due to radiation safety regulations and beam power constrains. The main influence of the stripper foil in conjunction with intrinsic astigmatism in the beam transport on beam brightness is discussed. The calculations show possibilities for brightness enhancement by using astigmatism corrections and asymmetric filling of the phase space volume in the x- and y-direction.

  5. Analysis of an "off-ladder" allele at the Penta D short tandem repeat locus.

    PubMed

    Yang, Y L; Wang, J G; Wang, D X; Zhang, W Y; Liu, X J; Cao, J; Yang, S L

    2015-01-01

    Kinship testing of a father and his son from Guangxi, China, the location of the Zhuang minority people, was performed using the PowerPlex® 18D System with a short tandem repeat typing kit. The results indicated that both the father and his son had an off-ladder allele at the Penta D locus, with a genetic size larger than that of the maximal standard allelic ladder. To further identify this locus, monogenic amplification, gene cloning, and genetic sequencing were performed. Sequencing analysis demonstrated that the fragment size of the Penta D-OL locus was 469 bp and the core sequence was [AAAGA]21, also called Penta D-21. The rare Penta D-21 allele was found to be distributed among the Zhuang population from the Guangxi Zhuang Autonomous Region of China; therefore, this study improved the range of DNA data available for this locus and enhanced our ability for individual identification of gene loci. PMID:26634472

  6. Flute instability and the associated radial transport in the tandem mirror with a divertor mirror cell

    SciTech Connect

    Katanuma, I.; Yagi, K.; Haraguchi, Y.; Ichioka, N.; Masaki, S.; Ichimura, M.; Imai, T.

    2010-11-15

    The flute instability and the associated radial transport are investigated in the tandem mirror with a divertor mirror cell (the GAMMA10 A-divertor) with help of computer simulation, where GAMMA10 is introduced [Inutake et al., Phys. Rev. Lett. 55, 939 (1985)]. The basic equations used in the simulation were derived on the assumption of an axisymmetric magnetic field. So the high plasma pressure in a nonaxisymmetric minimum-B anchor mirror cell, which is important for the flute mode stability, is taken into account by redefining the specific volume of a magnetic field line. It is found that the flute modes are stabilized by the minimum-B magnetic field even with a divertor mirror although its stabilizing effects are weaker than that without the divertor mirror. The flute instability enhances the radial transport by intermittently repeating the growing up and down of the Fourier amplitude of the flute instability in time.

  7. Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer

    NASA Technical Reports Server (NTRS)

    Tanaka, S.; Mielczarek, K.; Ovalle-Robles, R.; Wang, B.; Hsu, D.; Zakhidov, A. A.

    2009-01-01

    We demonstrate an organic photovoltaic cell with a monolithic tandem structure in parallel connection. Transparent multiwalled carbon nanotube sheets are used as an interlayer anode electrode for this parallel tandem. The characteristics of front and back cells are measured independently. The short circuit current density of the parallel tandem cell is larger than the currents of each individual cell. The wavelength dependence of photocurrent for the parallel tandem cell shows the superposition spectrum of the two spectral sensitivities of the front and back cells. The monolithic three-electrode photovoltaic cell indeed operates as a parallel tandem with improved efficiency.

  8. Tandem ligation of multipartite peptides with cell-permeable activity.

    PubMed

    Eom, Khee Dong; Miao, Zhenwei; Yang, Jin-Long; Tam, James P

    2003-01-01

    To prepare multipartite peptides with several functional cargoes including a cell-permeable sequence or transportant for intracellular delivery, tandem ligation of peptides is a convenient convergent approach with the fewest synthetic steps. It links three or four unprotected segments forming two or more regiospecific bonds consecutively without a deprotection step. This paper describes a tandem ligation strategy to prepare multipartite peptides with normal and branched architectures carrying a novel transportant peptide that is rich in arginine and proline to permit their cargoes to be translocated across membranes to affect their biological functions in cytoplasm. Our strategy consists of three ligation methods specific for amino terminal cysteine (Cys), serine/threonine (Ser/Thr), and N(alpha)-chloroacetylated amine to afford Xaa-Cys, Xaa-OPro (oxaproline) and Xaa-psiGly (pseudoglycine) at the ligation sites, respectively. Assembly of single-chain peptides from three different segments was achieved by the tandem Cys/OPro ligation to form two amide bonds, an Xaa-Cys and then an Xaa-OPro. Assembly of two- and three-chain peptides with branched architectures from four different segments was accomplished by tandem Cys/psiGly/OPro ligation. These NT-specific tandem ligation strategies were successful in generating cell-permeable multipartite peptides with one-, two-, and three-chain architectures, ranging in size from 52 to 75 residues and without the need of a protection or deprotection step. In addition, our results show that there is considerable flexibility in architectural design to obtain cell-permeable multipartite peptides containing a transportant sequence. PMID:12515508

  9. Development of an advanced spacecraft tandem mass spectrometer

    NASA Astrophysics Data System (ADS)

    Drew, Russell C.

    1992-03-01

    The purpose of this research was to apply current advanced technology in electronics and materials to the development of a miniaturized Tandem Mass Spectrometer that would have the potential for future development into a package suitable for spacecraft use. The mass spectrometer to be used as a basis for the tandem instrument would be a magnetic sector instrument, of Nier-Johnson configuration, as used on the Viking Mars Lander mission. This instrument configuration would then be matched with a suitable second stage MS to provide the benefits of tandem MS operation for rapid identification of unknown organic compounds. This tandem instrument is configured with a newly designed GC system to aid in separation of complex mixtures prior to MS analysis. A number of important results were achieved in the course of this project. Among them were the development of a miniaturized GC subsystem, with a unique desorber-injector, fully temperature feedback controlled oven with powered cooling for rapid reset to ambient conditions, a unique combination inlet system to the MS that provides for both membrane sampling and direct capillary column sample transfer, a compact and ruggedized alignment configuration for the MS, an improved ion source design for increased sensitivity, and a simple, rugged tandem MS configuration that is particularly adaptable to spacecraft use because of its low power and low vacuum pumping requirements. The potential applications of this research include use in manned spacecraft like the space station as a real-time detection and warning device for the presence of potentially harmful trace contaminants of the spacecraft atmosphere, use as an analytical device for evaluating samples collected on the Moon or a planetary surface, or even use in connection with monitoring potentially hazardous conditions that may exist in terrestrial locations such as launch pads, environmental test chambers or other sensitive areas. Commercial development of the technology could lead to a new family of environmental test instruments that would be small and portable, yet would give quick analyses of complex samples.

  10. Index versus tandem selection after repeated generations of selection.

    PubMed

    Villanueva, B; Kennedy, B W

    1993-02-01

    A theoretical comparison between two multiple-trait selection methods, index and tandem selection, after several generations of selection was carried out. An infinite number of loci determining the traits, directional and truncation selection, discrete generations and infinite population size were assumed. Under these assumptions, changes in genetic parameters over generations are due to linkage disequilibrium generated by selection. Changes continue for several generations until equilibrium is approached. Algebraic expressions for asymptotic responses from index selection can be derived if index weights are maintained constant across generations. Expressions at equilibrium for genetic parameters and responses are given for the index and its component traits. The loss in response by using initial index weights throughout all generations, instead of updating them to account for changes in genetic parameters, was analyzed. The benefit of using optimum weights was very small ranging from 0% to about 1.5% for all cases studied. Recurrence formulae to predict genetic parameters and responses at each generation of selection are given for both index and tandem selection. A comparison between expected response in the aggregate genotype at equilibrium from index and tandem selection is made considering two traits of economic importance. The results indicate that although index selection is more efficient for improving the aggregate breeding value, its relative efficiency with respect to tandem selection decreases after repeated cycles of selection. The reduction in relative efficiency is highest with the highest selection intensity and heritabilities and with negative correlations between the two traits. The advantage of index over tandem selection might be further reduced if changes in genetic parameters due to gene frequency changes produced by selection, random fluctuations due to the finite size of the population, and errors in estimation of parameters, were also considered. PMID:24196040

  11. Development of an advanced spacecraft tandem mass spectrometer

    NASA Technical Reports Server (NTRS)

    Drew, Russell C.

    1992-01-01

    The purpose of this research was to apply current advanced technology in electronics and materials to the development of a miniaturized Tandem Mass Spectrometer that would have the potential for future development into a package suitable for spacecraft use. The mass spectrometer to be used as a basis for the tandem instrument would be a magnetic sector instrument, of Nier-Johnson configuration, as used on the Viking Mars Lander mission. This instrument configuration would then be matched with a suitable second stage MS to provide the benefits of tandem MS operation for rapid identification of unknown organic compounds. This tandem instrument is configured with a newly designed GC system to aid in separation of complex mixtures prior to MS analysis. A number of important results were achieved in the course of this project. Among them were the development of a miniaturized GC subsystem, with a unique desorber-injector, fully temperature feedback controlled oven with powered cooling for rapid reset to ambient conditions, a unique combination inlet system to the MS that provides for both membrane sampling and direct capillary column sample transfer, a compact and ruggedized alignment configuration for the MS, an improved ion source design for increased sensitivity, and a simple, rugged tandem MS configuration that is particularly adaptable to spacecraft use because of its low power and low vacuum pumping requirements. The potential applications of this research include use in manned spacecraft like the space station as a real-time detection and warning device for the presence of potentially harmful trace contaminants of the spacecraft atmosphere, use as an analytical device for evaluating samples collected on the Moon or a planetary surface, or even use in connection with monitoring potentially hazardous conditions that may exist in terrestrial locations such as launch pads, environmental test chambers or other sensitive areas. Commercial development of the technology could lead to a new family of environmental test instruments that would be small and portable, yet would give quick analyses of complex samples.

  12. Fully integrated, fully automated generation of short tandem repeat profiles

    PubMed Central

    2013-01-01

    Background The generation of short tandem repeat profiles, also referred to as ‘DNA typing,’ is not currently performed outside the laboratory because the process requires highly skilled technical operators and a controlled laboratory environment and infrastructure with several specialized instruments. The goal of this work was to develop a fully integrated system for the automated generation of short tandem repeat profiles from buccal swab samples, to improve forensic laboratory process flow as well as to enable short tandem repeat profile generation to be performed in police stations and in field-forward military, intelligence, and homeland security settings. Results An integrated system was developed consisting of an injection-molded microfluidic BioChipSet cassette, a ruggedized instrument, and expert system software. For each of five buccal swabs, the system purifies DNA using guanidinium-based lysis and silica binding, amplifies 15 short tandem repeat loci and the amelogenin locus, electrophoretically separates the resulting amplicons, and generates a profile. No operator processing of the samples is required, and the time from swab insertion to profile generation is 84 minutes. All required reagents are contained within the BioChipSet cassette; these consist of a lyophilized polymerase chain reaction mix and liquids for purification and electrophoretic separation. Profiles obtained from fully automated runs demonstrate that the integrated system generates concordant short tandem repeat profiles. The system exhibits single-base resolution from 100 to greater than 500 bases, with inter-run precision with a standard deviation of ±0.05 - 0.10 bases for most alleles. The reagents are stable for at least 6 months at 22°C, and the instrument has been designed and tested to Military Standard 810F for shock and vibration ruggedization. A nontechnical user can operate the system within or outside the laboratory. Conclusions The integrated system represents the first generation of a turnkey approach to short tandem repeat profiling and has the potential for use in both the field (for example, police booking stations, the battlefield, borders and ports) and the forensic laboratory. PMID:23915594

  13. DaphniaDaphnia Genes Encoding Multiple Tandem ZnGenes Encoding Multiple Tandem Zn--finger Proteinsfinger Proteins Yang Bai and Gary W. Stuart

    E-print Network

    Stuart, Gary W.

    DaphniaDaphnia Genes Encoding Multiple Tandem ZnGenes Encoding Multiple Tandem Zn orthologous groups shared between humans and invertebrates. From a phylogenetic perspective, the Daphnia genome would be expected to contain identifiable members for most of these groups. Likely orthologs

  14. Tandem Repeats in Proteins: Prediction Algorithms and Biological Role

    PubMed Central

    Pellegrini, Marco

    2015-01-01

    Tandem repetitions in protein sequence and structure is a fascinating subject of research which has been a focus of study since the late 1990s. In this survey, we give an overview on the multi-faceted aspects of research on protein tandem repeats (PTR for short), including prediction algorithms, databases, early classification efforts, mechanisms of PTR formation and evolution, and synthetic PTR design. We also touch on the rather open issue of the relationship between PTR and flexibility (or disorder) in proteins. Detection of PTR either from protein sequence or structure data is challenging due to inherent high (biological) signal-to-noise ratio that is a key feature of this problem. As early in silico analytic tools have been key enablers for starting this field of study, we expect that current and future algorithmic and statistical breakthroughs will have a high impact on the investigations of the biological role of PTR. PMID:26442257

  15. Single P-N junction tandem photovoltaic device

    DOEpatents

    Walukiewicz, Wladyslaw (Kensington, CA); Ager, III, Joel W. (Berkeley, CA); Yu, Kin Man (Lafayette, CA)

    2011-10-18

    A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

  16. Single P-N junction tandem photovoltaic device

    DOEpatents

    Walukiewicz, Wladyslaw (Kensington, CA); Ager, III, Joel W. (Berkeley, CA); Yu, Kin Man (Lafayette, CA)

    2012-03-06

    A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

  17. Versatile communication strategies among tandem WW domain repeats

    PubMed Central

    Dodson, Emma Joy; Fishbain-Yoskovitz, Vered; Rotem-Bamberger, Shahar

    2015-01-01

    Interactions mediated by short linear motifs in proteins play major roles in regulation of cellular homeostasis since their transient nature allows for easy modulation. We are still far from a full understanding and appreciation of the complex regulation patterns that can be, and are, achieved by this type of interaction. The fact that many linear-motif-binding domains occur in tandem repeats in proteins indicates that their mutual communication is used extensively to obtain complex integration of information toward regulatory decisions. This review is an attempt to overview, and classify, different ways by which two and more tandem repeats cooperate in binding to their targets, in the well-characterized family of WW domains and their corresponding polyproline ligands. PMID:25710931

  18. Reflectance modulator based on tandem Fabry-Perot resonators

    SciTech Connect

    Fritz, I.J.; Klem, J.F.; Wendt, J.R. )

    1991-08-12

    We present calculations and data on a novel, electrically tunable reflector structure consisting of tandem Fabry--Perot resonators grown as a single epitaxial device. The device consists of three mirrors (quarter-wave stacks of AlGaAs and AlAs) separated by two cavities (one an AlGaAs alloy and the other a GaAs/AlGaAs superlattice) on a GaAs substrate. The tandem cavities produce a characteristic double-dipped reflectance spectrum which can be modulated by tunable electro-optic effects in the superlattice cavity. Our demonstration device has a modulation depth of {gt}10% over a 20 nm bandwidth with {lt}4 V of bias swing.

  19. Summary of results from the Tandem Mirror Experiment (TMX)

    SciTech Connect

    Simonen, T.C.

    1981-02-26

    This report summarizes results from the successful experimental operation of the Tandem Mirror Experiment (TMX) over the period October 1978 through September 1980. The experimental program, summarized by the DOE milestones given in Table 1-1, had three basic phases: (1) an 8-month checkout period, October 1978 through May 1979; (2) a 6-month initial period of operation, June through November 1979, during which the basic principles of the tandem configuration were demonstrated (i.e., plasma confinement was improved over that of a single-cell mirror); and (3) a 10-month period, December 1979 through September 1980, during which the initial TMX results were corroborated by additional diagnostic measurements and many detailed physics investigations were carried out. This report summarizes the early results, presents results of recent data analysis, and outlines areas of ongoing research and data analysis which will be reported in future journal publications.

  20. Interior of elevator tower, Block 31, looking northeast. Otis Tandem ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior of elevator tower, Block 31, looking northeast. Otis Tandem Gearless Elevator Hoist (1941); floor selector (far left), in foreground is the motor generator set which includes exciter (left), AC motor (center), DC generator (right); beyond is the passenger motor (right), hoist cable and drum (center), freight motor (left). - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  1. 27. Bollinger twinchain tandem, pigcasting machine, located at the north ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. Bollinger twin-chain tandem, pig-casting machine, located at the north end of the plant. Prior to closing, approximately 40 percent of the plant's: iron production was cast into pigs and sold to foundry customers. The pig-casting machine employed a controller, lime man, trough man, and crane operator. - Central Furnaces, 2650 Broadway, east bank of Cuyahoga River, Cleveland, Cuyahoga County, OH

  2. Rational design of ?-helical tandem repeat proteins with closed architectures.

    PubMed

    Doyle, Lindsey; Hallinan, Jazmine; Bolduc, Jill; Parmeggiani, Fabio; Baker, David; Stoddard, Barry L; Bradley, Philip

    2015-12-24

    Tandem repeat proteins, which are formed by repetition of modular units of protein sequence and structure, play important biological roles as macromolecular binding and scaffolding domains, enzymes, and building blocks for the assembly of fibrous materials. The modular nature of repeat proteins enables the rapid construction and diversification of extended binding surfaces by duplication and recombination of simple building blocks. The overall architecture of tandem repeat protein structures--which is dictated by the internal geometry and local packing of the repeat building blocks--is highly diverse, ranging from extended, super-helical folds that bind peptide, DNA, and RNA partners, to closed and compact conformations with internal cavities suitable for small molecule binding and catalysis. Here we report the development and validation of computational methods for de novo design of tandem repeat protein architectures driven purely by geometric criteria defining the inter-repeat geometry, without reference to the sequences and structures of existing repeat protein families. We have applied these methods to design a series of closed ?-solenoid repeat structures (?-toroids) in which the inter-repeat packing geometry is constrained so as to juxtapose the amino (N) and carboxy (C) termini; several of these designed structures have been validated by X-ray crystallography. Unlike previous approaches to tandem repeat protein engineering, our design procedure does not rely on template sequence or structural information taken from natural repeat proteins and hence can produce structures unlike those seen in nature. As an example, we have successfully designed and validated closed ?-solenoid repeats with a left-handed helical architecture that--to our knowledge--is not yet present in the protein structure database. PMID:26675735

  3. On the continuous plug potential profile in a tandem mirror

    NASA Astrophysics Data System (ADS)

    Katanuma, I.; Kiwamoto, Y.; Tatematsu, Y.; Ishii, K.; Saito, T.; Tamano, T.; Yatsu, K.

    1998-05-01

    The plug potential is formed experimentally, even without high energy sloshing ion population in the end-mirror cells of a tandem mirror. It has been shown analytically that the plug potential can be formed in the present experimental conditions by using the plausible distribution functions of ions and electrons and a small ionization source. In this paper, the required ionization rate is estimated for the continuous potential profile around the plug by using Emmert's source.

  4. Crux: rapid open source protein tandem mass spectrometry analysis.

    PubMed

    McIlwain, Sean; Tamura, Kaipo; Kertesz-Farkas, Attila; Grant, Charles E; Diament, Benjamin; Frewen, Barbara; Howbert, J Jeffry; Hoopmann, Michael R; Käll, Lukas; Eng, Jimmy K; MacCoss, Michael J; Noble, William Stafford

    2014-10-01

    Efficiently and accurately analyzing big protein tandem mass spectrometry data sets requires robust software that incorporates state-of-the-art computational, machine learning, and statistical methods. The Crux mass spectrometry analysis software toolkit ( http://cruxtoolkit.sourceforge.net ) is an open source project that aims to provide users with a cross-platform suite of analysis tools for interpreting protein mass spectrometry data. PMID:25182276

  5. Crux: Rapid Open Source Protein Tandem Mass Spectrometry Analysis

    PubMed Central

    2015-01-01

    Efficiently and accurately analyzing big protein tandem mass spectrometry data sets requires robust software that incorporates state-of-the-art computational, machine learning, and statistical methods. The Crux mass spectrometry analysis software toolkit (http://cruxtoolkit.sourceforge.net) is an open source project that aims to provide users with a cross-platform suite of analysis tools for interpreting protein mass spectrometry data. PMID:25182276

  6. Short-pulse CO? laser with longitudinal tandem discharge tube.

    PubMed

    Uno, K; Akitsu, T; Jitsuno, T

    2014-10-01

    We developed a longitudinally excited CO2 laser with a tandem discharge tube. The tandem scheme was constituted of two 30-cm long discharge tubes connected with an intermediate electrode. Two parts, each consisting of a charged capacitance and a 30-cm long discharge tube, were electrically connected in parallel and switched by a spark gap. The tandem scheme produced a short laser pulse like that of a TEA-CO2 laser with a charging voltage of -24.8 kV, which was smaller than the -40.0 kV charging voltage of our previous CO2 laser. At a gas pressure of 3.8 kPa, the spike pulse width was 145 ns, the pulse tail length was 58.8 ?s, the output energy was 52.0 mJ, and the spike pulse energy was 2.4 mJ. We also investigated the dependence of the laser pulse and the discharge voltage on gas pressure. PMID:25362375

  7. The mechanics and behavior of cliff swallows during tandem flights.

    PubMed

    Shelton, Ryan M; Jackson, Brandon E; Hedrick, Tyson L

    2014-08-01

    Cliff swallows (Petrochelidon pyrrhonota) are highly maneuverable social birds that often forage and fly in large open spaces. Here we used multi-camera videography to measure the three-dimensional kinematics of their natural flight maneuvers in the field. Specifically, we collected data on tandem flights, defined as two birds maneuvering together. These data permit us to evaluate several hypotheses on the high-speed maneuvering flight performance of birds. We found that high-speed turns are roll-based, but that the magnitude of the centripetal force created in typical maneuvers varied only slightly with flight speed, typically reaching a peak of ~2 body weights. Turning maneuvers typically involved active flapping rather than gliding. In tandem flights the following bird copied the flight path and wingbeat frequency (~12.3 Hz) of the lead bird while maintaining position slightly above the leader. The lead bird turned in a direction away from the lateral position of the following bird 65% of the time on average. Tandem flights vary widely in instantaneous speed (1.0 to 15.6 m s(-1)) and duration (0.72 to 4.71 s), and no single tracking strategy appeared to explain the course taken by the following bird. PMID:24855672

  8. Tandem cylinder aerodynamic sound control using porous coating

    NASA Astrophysics Data System (ADS)

    Liu, Hanru; Azarpeyvand, Mahdi; Wei, Jinjia; Qu, Zhiguo

    2015-01-01

    This study is concerned with the application of porous coatings as a passive flow control method for reducing the aerodynamic sound from tandem cylinders. The aim here is to perform a parametric proof-of-concept study to investigate the effectiveness of porous treatment on bare tandem cylinders to control and regularize the vortex shedding and flow within the gap region between the two bluff bodies, and thereby control the aerodynamic sound generation mechanism. The aerodynamic simulations are performed using 2D transient RANS approach with k - ? turbulence model, and the acoustic computations are carried out using the standard Ffowcs Williams-Hawkings (FW-H) acoustic analogy. Numerical flow and acoustic results are presented for bare tandem cylinders and porous-covered cylinders, with different porosities and thicknesses. Experimental flow and acoustic data are also provided for comparison. Results show that the proper use of porous coatings can lead to stabilization of the vortex shedding within the gap region, reduction of the vortex shedding interaction with the downstream body, and therefore the generation of tonal and broadband noise. It has also been observed that the magnitude and the frequency of the primary tone reduce significantly as a result of the flow regularization. The proposed passive flow-induced noise and vibration control method can potentially be used for other problems involving flow interaction with bluff bodies.

  9. Preliminary design of a Tandem-Mirror-Next-Step facility

    SciTech Connect

    Damm, C.C.; Doggett, J.N.; Bulmer, R.H.

    1980-12-18

    The Tandem-Mirror-Next-Step (TMNS) facility is designed to demonstrate the engineering feasibility of a tandem-mirror reactor. The facility is based on a deuterium-tritium (D-T) burning, tandem-mirror device with a fusion power output of 245 MW. The fusion power density in the central cell is 2.1 MW/m/sup 3/, with a resultant neutron wall loading of 0.5 MW/m/sup 2/. Overall machine length is 116 m, and the effective central-cell length is 50.9 m. The magnet system includes end cells with yin-yang magnets to provide magnetohydrodynamic (MHD) stability and thermal-barrier cells to help achieve a plasma Q of 4.7 (where Q = fusion power/injected power). Neutral beams at energies up to 200 keV are used for plasma heating, fueling, and barrier pumping. Electron cyclotron resonant heating at 50 and 100 GHz is used to control the electron temperature in the barriers. Based on the resulting engineering design, the overall cost of the facility is estimated to be just under $1 billion. Unresolved physics issues include central-cell ..beta..-limits against MHD ballooning modes (the assumed reference value of ..beta.. exceeds the current theory-derived limit), and the removal of thermalized ..cap alpha..-particles from the plasma.

  10. Sticky interconnect for solution-processed tandem solar cells.

    PubMed

    Tung, Vincent C; Kim, Jaemyung; Cote, Laura J; Huang, Jiaxing

    2011-06-22

    Graphene oxide (GO) can be viewed as a two-dimensional, random diblock copolymer with distributed nanosize graphitic patches and highly oxidized domains, thus capable of guiding the assembly of other materials through both ?-? stacking and hydrogen bonding. Upon mixing GO and conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in water, a dispersion with dramatically increased viscosity is obtained, which turns into sticky thin films upon casting. Surprisingly, the insulating GO makes PEDOT much more conductive by altering its chain conformation and morphology. The GO/PEDOT gel can function as a metal-free solder for creating mechanical and electrical connections in organic optoelectronic devices. As a proof-of-concept, polymer tandem solar cells have been fabricated by a direct adhesive lamination process enabled by the sticky GO/PEDOT film. The sticky interconnect can greatly simplify the fabrication of organic tandem architectures, which has been quite challenging via solution processing. Thus, it could facilitate the construction of high-efficiency tandem solar cells with different combinations of solution-processable materials. PMID:21615169

  11. Colon-targeted delivery of piceatannol enhances anti-colitic effects of the natural product: potential molecular mechanisms for therapeutic enhancement

    PubMed Central

    Yum, Soohwan; Jeong, Seongkeun; Lee, Sunyoung; Nam, Joon; Kim, Wooseong; Yoo, Jin-Wook; Kim, Min-Soo; Lee, Bok Luel; Jung, Yunjin

    2015-01-01

    Piceatannol (PCT), an anti-colitic natural product, undergoes extensive Phase II hepatic metabolism, resulting in very low bioavailability. We investigated whether colon-targeted delivery of PCT could enhance anti-colitic effects and how therapeutic enhancement occurred at the molecular level. Molecular effects of PCT were examined in human colon carcinoma cells and inflamed colons. The anti-colitic effects of PCT in a colon-targeted capsule (colon-targeted PCT) were compared with PCT in a gelatin capsule (conventional PCT) in a trinitrobenzene sulfonic acid-induced rat colitis model. Colon-targeted PCT elicited greatly enhanced recovery of the colonic inflammation. In HCT116 cells, PCT inhibited nuclear factor kappaB while activating anti-colitic transcription factors, nuclear factor-erythroid 2 (NF-E2) p45-related factor 2, and hypoxia-inducible factor-1. Colon-targeted PCT, but not conventional PCT, modulated production of the target gene products of the transcription factors in the inflamed colonic tissues. Rectal administration of PCT, which simulates the therapeutic action of colon-targeted PCT, also ameliorated rat colitis and reproduced the molecular effects in the inflamed colonic tissues. Colon-targeted delivery increased therapeutic efficacy of PCT against colitis, likely resulting from multitargeted effects exerted by colon-targeted PCT. The drug delivery technique may be useful for therapeutic optimization of anti-colitic lead compounds including natural products. PMID:26273188

  12. Drift wave stability and transport in tandem mirrors

    NASA Astrophysics Data System (ADS)

    Pratt, Jane Lillian

    In recent years experimental advances at the GAMMA-10 facility in Tsukuba, Japan have shown that tandem mirrors should remain an important subject for theoretical study. The absence of toroidal curvature and relatively weak internal plasma parallel currents in a tandem mirror gives the mirror system strongly favorable stability and transport properties compared with toroidal systems. GAMMA-10 experiments (T. Cho et al. PRL (97), 2006) demonstrate that sheared plasma rotation suppresses turbulent radial losses by controlling radial potential profiles. Achievements of the GAMMA-10 include 2.5 keV ion confining potentials and electron temperatures approaching 1 keV (T. Cho, Private correspondence, Dec 24th, 2006). Total energy confinement times for the GAMMA-10 experiment are significantly larger than corresponding empirical confinement times in toroidal devices. At the temperatures currently achieved in the GAMMA-10, the end loss rate tau?? ? 100 ms so that radial losses determine the energy confinement time tauE, as intended in tandem mirror reactor designs (R. F. Post, T.K. Fowler, et al., Fusion Science and Technology, (47), 2005). The most current measurements of tauE are on the order of 72 ms. Tandem mirrors exhibit a qualitatively different type of drift wave transport than do toroidal devices, as we have shown by developing confinement time scaling predictions (J. Pratt and W. Horton, Phys. Plasmas (13), 2006. W. Horton, J. Pratt, H.L. Berk, M. Hirata. Proceedings of the Open Magnetic Systems For Plasma Confinement Conference. Tsukuba, Japan, July 17-21, 2006). These predictions use a variety of standard transport models, e.g., Bohm, gyro-Bohm, and electron-temperature gradient models. We analyze electrostatic drift wave eigenmodes for the electrostatic potential and the magnetic perturbation in the GAMMA-10. We use teraFLOPS speed, large scale parallel computers to integrate the orbits in models of the drift wave losses in the GAMMA-10. We extrapolate these results to reactor designs for the kinetically stabilized tandem mirror reactor proposed by Post et al., and discuss implications for its stability, transport, and performance.

  13. Enhanced oil recovery system

    DOEpatents

    Goldsberry, Fred L. (Spring, TX)

    1989-01-01

    All energy resources available from a geopressured geothermal reservoir are used for the production of pipeline quality gas using a high pressure separator/heat exchanger and a membrane separator, and recovering waste gas from both the membrane separator and a low pressure separator in tandem with the high pressure separator for use in enhanced oil recovery, or in powering a gas engine and turbine set. Liquid hydrocarbons are skimmed off the top of geothermal brine in the low pressure separator. High pressure brine from the geothermal well is used to drive a turbine/generator set before recovering waste gas in the first separator. Another turbine/generator set is provided in a supercritical binary power plant that uses propane as a working fluid in a closed cycle, and uses exhaust heat from the combustion engine and geothermal energy of the brine in the separator/heat exchanger to heat the propane.

  14. Reactor issues for tandem mirrors operating in the negative-potential mode

    SciTech Connect

    Perkins, L.J.; Campbell, R.B.

    1985-12-02

    During 1985, interest has been revived at LLNL in tandem mirrors operating in the negative-potential mode. The negative tandem is formed by combining ECRH-sustained hot electron end cell plasmas with pumping mechanisms to remove trapped ions from the end cells. No sloshing ions are required. The resulting negative potential in the end cells confines the central cell electrons. The requirement of charge neutrality causes the ambipolar potential of the central cell to become negative relative to the end wall (hence, the name ''negative' tandem mirror), thereby providing central cell ion confinement. This potential distribution is the exact inverse of the axial distribution for the conventional (positive) tandem mirror without thermal barriers. In the negative tandem mirror, central cell electrons are confined electrostatically, end cell electrons are confined magnetically, and ions are confined electrostatically everywhere. In this report, we briefly assess the reactor issues pertinent to the operation of the tandem mirror in the negative mode. 7 refs., 5 figs.

  15. Tandem mirror reactor studies at Lawrence Livermore National Laboratory, FY 1980

    SciTech Connect

    Carlson, G.A.; Neef, W.S. Jr.

    1981-03-20

    The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror Fusion Test Facility (MFTF-B) in 1984. Continued analysis and conceptual design over this period will evolve the optimal configuration and parameters for a power-producing reactor. In this article we describe the progress we have made in this reactor design study effort during 1980.

  16. PTGBase: an integrated database to study tandem duplicated genes in plants

    PubMed Central

    Yu, Jingyin; Ke, Tao; Tehrim, Sadia; Sun, Fengming; Liao, Boshou; Hua, Wei

    2015-01-01

    Tandem duplication is a wide-spread phenomenon in plant genomes and plays significant roles in evolution and adaptation to changing environments. Tandem duplicated genes related to certain functions will lead to the expansion of gene families and bring increase of gene dosage in the form of gene cluster arrays. Many tandem duplication events have been studied in plant genomes; yet, there is a surprising shortage of efforts to systematically present the integration of large amounts of information about publicly deposited tandem duplicated gene data across the plant kingdom. To address this shortcoming, we developed the first plant tandem duplicated genes database, PTGBase. It delivers the most comprehensive resource available to date, spanning 39 plant genomes, including model species and newly sequenced species alike. Across these genomes, 54?130 tandem duplicated gene clusters (129?652 genes) are presented in the database. Each tandem array, as well as its member genes, is characterized in complete detail. Tandem duplicated genes in PTGBase can be explored through browsing or searching by identifiers or keywords of functional annotation and sequence similarity. Users can download tandem duplicated gene arrays easily to any scale, up to the complete annotation data set for an entire plant genome. PTGBase will be updated regularly with newly sequenced plant species as they become available. Database URL: http://ocri-genomics.org/PTGBase/. PMID:25797062

  17. Quantification of endogenous brassinosteroids in sub-gram plant tissues by in-line matrix solid-phase dispersion-tandem solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Lu; Duan, Chunfeng; Wu, Dapeng; Guan, Yafeng

    2014-09-12

    A matrix solid-phase dispersion (MSPD)-tandem mixed mode anion exchange (MAX)-mixed mode cation exchange (MCX) solid phase extraction-high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for quantification of six endogenous brassinosteroids (BRs) (24-epibrassinolide, 24-epicastasterone, 6-deoxo-24-epicastasterone, dolichosterone, teasterone and typhasterol) in rice plant tissues. Non-polar interferences were removed effectively by C8 dispersant used in MSPD, while the following tandem MAX-MCX process facilitated the elimination of polar and ionizable compounds. The weak reversed-phase retention feature of MAX-MCX leaded to good compatibility of the elution solvents in the in-line coupled MSPD-MAX-MCX system. This system was optimized for extraction and purification of BRs in plant samples. The effects of the type of solid phase, the elution solvent, the extraction temperature and the clean-up material were studied. Before HPLC separation, BRs purified were derivatized by m-aminophenylboronic acid to enhance the sensitivity of MS/MS to BRs. Compared with traditional liquid-liquid extraction and solid phase extraction (LLE-SPE), the proposed MSPD-MAX-MCX method showed higher extraction efficiency, lower matrix effect, and advantages of easy manipulation and time-saving. The in-line MSPD-MAX-MCX coupled with HPLC-MS/MS method provided a linear response over two orders of magnitude of BRs concentration with correlation coefficients above 0.9982, limits of detection between 0.008 and 0.04ngmL(-1), relative standard deviations (RSDs) below 29.4%, and recoveries above 77.8%. The proposed method has been successfully applied to analysis of endogenous BRs in rice plant at booting stage and maturity stage. PMID:25092597

  18. Forensic analysis of printing inks using tandem Laser Induced Breakdown Spectroscopy and Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Subedi, Kiran; Trejos, Tatiana; Almirall, José

    2015-01-01

    Elemental analysis, using either LA-ICP-MS or LIBS, can be used for the chemical characterization of materials of forensic interest to discriminate between source materials originating from different sources and also for the association of materials known to originate from the same source. In this study, a tandem LIBS/LA-ICP-MS system that combines the benefits of both LIBS and LA-ICP-MS was evaluated for the characterization of samples of printing inks (toners, inkjets, intaglio and offset.). The performance of both laser sampling methods is presented. A subset of 9 black laser toners, 10 colored (CMYK) inkjet samples, 12 colored (CMYK) offset samples and 12 intaglio inks originating from different manufacturing sources were analyzed to evaluate the discrimination capability of the tandem method. These samples were selected because they presented a very similar elemental profile by LA-ICP-MS. Although typical discrimination between different ink sources is found to be > 99% for a variety of inks when only LA-ICP-MS was used for the analysis, additional discrimination was achieved by combining the elemental results from the LIBS analysis to the LA-ICP-MS analysis in the tandem technique, enhancing the overall discrimination capability of the individual laser ablation methods. The LIBS measurements of the Ca, Fe, K and Si signals, in particular, improved the discrimination for this specific set of different ink samples previously shown to exhibit very similar LA-ICP-MS elemental profiles. The combination of these two techniques in a single setup resulted in better discrimination of the printing inks with two distinct fingerprint spectra, providing information from atomic/ionic emissions and isotopic composition (m/z) for each ink sample.

  19. A T-cell specific transcriptional enhancer element 3 prime of C sub. alpha. in the human T-cell receptor. alpha. locus

    SciTech Connect

    Ho, Icheng; Yang, Lihsuan; Morle, G.; Leiden, J.M. )

    1989-09-01

    A transcriptional enhancer element has been identified 4.5 kilobases 3{prime} of C{sub {alpha}} (constant region {alpha} chain) in the human T-cell receptor (TCR) {alpha}-chain locus. This enhancer is active on both a TCR V{sub {alpha}} (variable region {alpha} chain) promoter and the minimal simian virus 40 promoter in TCR {alpha}/{beta} Jurkat and EL4 cells but is inactive on a V{sub {alpha}} promoter TCR {gamma}/{delta} PEER and Molt-13 cells, clone 13 B cells, and HeLa fibroblasts. The enhancer has been localized to a 116-base-pair BstXI/Dra I restriction enzyme fragment, which lacks immunoglobulin octamer and {kappa}B enhancer motifs but does contain a consensus cAMP-response element (CRE). DNase I footprint analyses demonstrated that the minimal enhancer contains two binding sites for Jurkat nuclear proteins. One of these sites corresponds to the CRE, while the other does not correspond to a known transcriptional enhancer motif. These data support a model in which TCR {alpha} gene transcription is regulated by a unique set of cis-acting sequences and trans-acting factors, which are differentially active in cells of the TCR {alpha}/{beta} lineage. In addition, the TCR {alpha} enhancer may play a role in activating oncogene expression in T-lymphoblastoid tumors that have previously been shown to display chromosomal translocations into the human TCR {alpha} locus.

  20. Interpretation of tandem mass spectra obtained from cyclic nonribosomal peptides.

    PubMed

    Liu, Wei-Ting; Ng, Julio; Meluzzi, Dario; Bandeira, Nuno; Gutierrez, Marcelino; Simmons, Thomas L; Schultz, Andrew W; Linington, Roger G; Moore, Bradley S; Gerwick, William H; Pevzner, Pavel A; Dorrestein, Pieter C

    2009-06-01

    Natural and non-natural cyclic peptides are a crucial component in drug discovery programs because of their considerable pharmaceutical properties. Cyclosporin, microcystins, and nodularins are all notable pharmacologically important cyclic peptides. Because these biologically active peptides are often biosynthesized nonribosomally, they often contain nonstandard amino acids, thus increasing the complexity of the resulting tandem mass spectrometry data. In addition, because of the cyclic nature, the fragmentation patterns of many of these peptides showed much higher complexity when compared to related counterparts. Therefore, at the present time it is still difficult to annotate cyclic peptides MS/MS spectra. In this current work, an annotation program was developed for the annotation and characterization of tandem mass spectra obtained from cyclic peptides. This program, which we call MS-CPA is available as a web tool (http://lol.ucsd.edu/ms-cpa_v1/Input.py). Using this program, we have successfully annotated the sequence of representative cyclic peptides, such as seglitide, tyrothricin, desmethoxymajusculamide C, dudawalamide A, and cyclomarins, in a rapid manner and also were able to provide the first-pass structure evidence of a newly discovered natural product based on predicted sequence. This compound is not available in sufficient quantities for structural elucidation by other means such as NMR. In addition to the development of this cyclic annotation program, it was observed that some cyclic peptides fragmented in unexpected ways resulting in the scrambling of sequences. In summary, MS-CPA not only provides a platform for rapid confirmation and annotation of tandem mass spectrometry data obtained with cyclic peptides but also enables quantitative analysis of the ion intensities. This program facilitates cyclic peptide analysis, sequencing, and also acts as a useful tool to investigate the uncommon fragmentation phenomena of cyclic peptides and aids the characterization of newly discovered cyclic peptides encountered in drug discovery programs. PMID:19413302

  1. Tandem-repeat protein domains across the tree of life

    PubMed Central

    Jernigan, Kristin K.

    2015-01-01

    Tandem-repeat protein domains, composed of repeated units of conserved stretches of 20–40 amino acids, are required for a wide array of biological functions. Despite their diverse and fundamental functions, there has been no comprehensive assessment of their taxonomic distribution, incidence, and associations with organismal lifestyle and phylogeny. In this study, we assess for the first time the abundance of armadillo (ARM) and tetratricopeptide (TPR) repeat domains across all three domains in the tree of life and compare the results to our previous analysis on ankyrin (ANK) repeat domains in this journal. All eukaryotes and a majority of the bacterial and archaeal genomes analyzed have a minimum of one TPR and ARM repeat. In eukaryotes, the fraction of ARM-containing proteins is approximately double that of TPR and ANK-containing proteins, whereas bacteria and archaea are enriched in TPR-containing proteins relative to ARM- and ANK-containing proteins. We show in bacteria that phylogenetic history, rather than lifestyle or pathogenicity, is a predictor of TPR repeat domain abundance, while neither phylogenetic history nor lifestyle predicts ARM repeat domain abundance. Surprisingly, pathogenic bacteria were not enriched in TPR-containing proteins, which have been associated within virulence factors in certain species. Taken together, this comparative analysis provides a newly appreciated view of the prevalence and diversity of multiple types of tandem-repeat protein domains across the tree of life. A central finding of this analysis is that tandem repeat domain-containing proteins are prevalent not just in eukaryotes, but also in bacterial and archaeal species. PMID:25653910

  2. Tandem-repeat protein domains across the tree of life.

    PubMed

    Jernigan, Kristin K; Bordenstein, Seth R

    2015-01-01

    Tandem-repeat protein domains, composed of repeated units of conserved stretches of 20-40 amino acids, are required for a wide array of biological functions. Despite their diverse and fundamental functions, there has been no comprehensive assessment of their taxonomic distribution, incidence, and associations with organismal lifestyle and phylogeny. In this study, we assess for the first time the abundance of armadillo (ARM) and tetratricopeptide (TPR) repeat domains across all three domains in the tree of life and compare the results to our previous analysis on ankyrin (ANK) repeat domains in this journal. All eukaryotes and a majority of the bacterial and archaeal genomes analyzed have a minimum of one TPR and ARM repeat. In eukaryotes, the fraction of ARM-containing proteins is approximately double that of TPR and ANK-containing proteins, whereas bacteria and archaea are enriched in TPR-containing proteins relative to ARM- and ANK-containing proteins. We show in bacteria that phylogenetic history, rather than lifestyle or pathogenicity, is a predictor of TPR repeat domain abundance, while neither phylogenetic history nor lifestyle predicts ARM repeat domain abundance. Surprisingly, pathogenic bacteria were not enriched in TPR-containing proteins, which have been associated within virulence factors in certain species. Taken together, this comparative analysis provides a newly appreciated view of the prevalence and diversity of multiple types of tandem-repeat protein domains across the tree of life. A central finding of this analysis is that tandem repeat domain-containing proteins are prevalent not just in eukaryotes, but also in bacterial and archaeal species. PMID:25653910

  3. Producing thermochemical hydrogen with the tandem-mirror reactor

    SciTech Connect

    Werner, R.W.; Hickman, R.G.

    1982-05-07

    Fusion power holds the promise to supply not only electricity but also fuels to meet the balance of our energy needs. A new integrated power and breeding blanket design is described for tandem mirror reactors. The blanket incorporates features that make it suitable for synthetic fuel production. In particular, it is matched to the thermal and electrical power requirements of the General Atomic water-splitting process for production of hydrogen. Some improvements to the high temperature chemical process steps are described. These improvements are expected to allow production of hydrogen at about $13/GJ wholesale, including financing costs, capital amortization, and profit.

  4. Current- and lattice-matched tandem solar cell

    DOEpatents

    Olson, J.M.

    1985-10-21

    A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga/sub x/In/sub 1-x/P (0.505 equal to or less than x equal to or less than 0.515) top cell semiconductor lattice-matched to a GaAs bottom cell semiconductor at a low resistance heterojunction, preferably a p/sup +//n/sup +/ heterojunction between the cells. The top and bottom cells are both lattice-matched and current-matched for high efficiency solar radiation conversion to electrical energy.

  5. Time-Of Potential Diagnostics for Tandem Mirrors.

    NASA Astrophysics Data System (ADS)

    Archer, Branch T., III

    1987-09-01

    Two time-of-flight potential diagnostics for tandem mirrors are investigated. These diagnostics are designed to measure axial potential variations in tandem mirror plasma geometries. One approach investigated employs an electron beam as a potential probe, and the other employs a helium ion beam. In each case, a modulated beam is injected along the magnetic axis of the magnetic field into the plasma confinement region. The velocity of the beam particles varies as the beam moves through variations in the electrostatic potential. Since the beam is modulated, variations in beam velocity modify the modulation phase of the beam along the beam trajectory. In the case of the electron beam, the phase of the beam is remotely detected by using a Rogowski loop which encircles the plasma. The phase of the helium ion beam can be measured by observing the light emitted by the helium ions. A Rogowski loop was built and installed on the Berkeley Ten Meter Multiple Mirror Experiment (MMX) to measure plasma potentials using a modulated electron beam. An existing electron gun design was improved for use in this experiment. The criteria for the loop design and response characteristics are presented, along with results obtained for the plasma potential in the device. A theoretical study was made regarding the feasibility of the modulated ion beam concept for measuring potentials in the TMX-U and MFTF-B tandem mirror machines at the Lawrence Livermore National Laboratory. The estimated potential uncertainties for these machines appear quite small, provided an ion beam of the required quality can be modulated at a high enough frequency. In order to address this concern, a 5 kV, 10 mA ion beam was designed, fabricated, and tested. The beam was extracted from a mirror-confined plasma which was driven by an 800W, 2.45 GHz microwave source. A variety of approaches were attempted in order to produce a modulated beam. Eventually a method was developed to produce a 20% modulation of the beam at 1-2 MHz. Thus use of the ion beam technique to measure axial potential variations on large tandem mirrors should be feasible.

  6. Search for the optimal linker in tandem hairpin polyamides.

    PubMed

    Kers, Inger; Dervan, Peter B

    2002-10-01

    In order to target specific DNA sequences >or=10 base pairs in size by minor groove binding ligands, a search for the optimal linker in dimers of hairpin polyamides was initiated. Two series of tandem polyamides ImPyIm-(R)[ImPyIm-(R)(H2N)gamma-PyPyPy-L](HN)gamma-PyPyPy-beta-Dp (1a-e), where L represents a series of 4-8 carbon long aliphatic amino acid linkers, and ImPyIm-(R)[ImPyIm-(R)(H2N)gamma-PyPyPyIm-L](HN)gamma-PyPyPy-beta-Dp (2a-e), where L represents a series of 2-6 carbon long aliphatic amino acid linkers, were synthesized and characterized by quantitative DNase I footprinting. beta, gamma and Dp represents beta-alanine, gamma-aminobutyric acid, and 3-(dimethylamino)propylamine, respectively. It was found that the five-carbon 5-aminovaleric acid (delta), is suitable to span one base-pair (bp) of DNA when incorporated into a tandem polyamide. ImPyIm-(R)[ImPyIm-(R)(H2N)gamma-PyPyPy-delta](HN)gamma-PyPyPy-beta-Dp (1b) binds the 10 bp binding-site 5'-AGTGAAGTGA-3' with equilibrium association constant K(a)=3.2 x 10(10) M(-1) and ImPyIm-(R)[ImPyIm-(R)(H2N)gamma-PyPyPyIm-delta](HN)gamma-PyPyPy-beta-Dp (2d) binds the 11 bp binding-site 5'-AGTGATAGTGA-3' with K(a)=9.7 x 10(9) M(-1). Tandem 1b also bind the 11 bp site but with lower affinity affording a 15-fold specificity for the shorter binding site. Replacing a methylene group in the amino acid linker with an oxygen atom to form tandem polyamide ImPyIm-(R)[ImPyIm-(R)(H2N)gamma-PyPyPy-E](HN)gamma-PyPyPy-beta-Dp (4) where E represents the ether linker, resulted in that an 80-fold specificity for the 10 bp binding site over the 11 bp site. PMID:12150881

  7. Plasma performance study for the tandem mirror reactor

    SciTech Connect

    Boghosian, B.M.

    1980-01-01

    A computer code was developed for assessing the performance of new variations on the thermal barrier idea for tandem mirror reactors (TMR's). The code solves the particle and energy balance equations simultaneously for each species of particles in each portion of the machine. The code is thus able to determine the neutral beam and ECRH injection powers that are required to sustain an equilibrium situation, and, from these, to determine the machine's Q value. This paper focuses on the methodology and numerical algorithms used in accomplishing this solution. We plan to use this code to compare the A-cell barrier TMR with axisymmetric TMR's.

  8. Expanding the toolbox of tandem mass spectrometry with algorithms to identify mass spectra from more than one peptide

    E-print Network

    Wang, Jian

    sequence database searching in proteomics data analysis.database search of mixture tandem mass spectra”, Molecular & Cellular Proteomics,database search of mixture tandem mass spectra”, Molecular & Cellular Proteomics,

  9. Low-temperature-processed efficient semi-transparent planar perovskite solar cells for bifacial and tandem applications.

    PubMed

    Fu, Fan; Feurer, Thomas; Jäger, Timo; Avancini, Enrico; Bissig, Benjamin; Yoon, Songhak; Buecheler, Stephan; Tiwari, Ayodhya N

    2015-01-01

    Semi-transparent perovskite solar cells are highly attractive for a wide range of applications, such as bifacial and tandem solar cells; however, the power conversion efficiency of semi-transparent devices still lags behind due to missing suitable transparent rear electrode or deposition process. Here we report a low-temperature process for efficient semi-transparent planar perovskite solar cells. A hybrid thermal evaporation-spin coating technique is developed to allow the introduction of PCBM in regular device configuration, which facilitates the growth of high-quality absorber, resulting in hysteresis-free devices. We employ high-mobility hydrogenated indium oxide as transparent rear electrode by room-temperature radio-frequency magnetron sputtering, yielding a semi-transparent solar cell with steady-state efficiency of 14.2% along with 72% average transmittance in the near-infrared region. With such semi-transparent devices, we show a substantial power enhancement when operating as bifacial solar cell, and in combination with low-bandgap copper indium gallium diselenide we further demonstrate 20.5% efficiency in four-terminal tandem configuration. PMID:26576667

  10. Low-temperature-processed efficient semi-transparent planar perovskite solar cells for bifacial and tandem applications

    NASA Astrophysics Data System (ADS)

    Fu, Fan; Feurer, Thomas; Jäger, Timo; Avancini, Enrico; Bissig, Benjamin; Yoon, Songhak; Buecheler, Stephan; Tiwari, Ayodhya N.

    2015-11-01

    Semi-transparent perovskite solar cells are highly attractive for a wide range of applications, such as bifacial and tandem solar cells; however, the power conversion efficiency of semi-transparent devices still lags behind due to missing suitable transparent rear electrode or deposition process. Here we report a low-temperature process for efficient semi-transparent planar perovskite solar cells. A hybrid thermal evaporation-spin coating technique is developed to allow the introduction of PCBM in regular device configuration, which facilitates the growth of high-quality absorber, resulting in hysteresis-free devices. We employ high-mobility hydrogenated indium oxide as transparent rear electrode by room-temperature radio-frequency magnetron sputtering, yielding a semi-transparent solar cell with steady-state efficiency of 14.2% along with 72% average transmittance in the near-infrared region. With such semi-transparent devices, we show a substantial power enhancement when operating as bifacial solar cell, and in combination with low-bandgap copper indium gallium diselenide we further demonstrate 20.5% efficiency in four-terminal tandem configuration.

  11. Charge generation layers for all-solution processed organic tandem light emitting diodes with regular device architecture

    NASA Astrophysics Data System (ADS)

    Höfle, Stefan; Bernhard, Christoph; Bruns, Michael; Kübel, Christian; Scherer, Torsten; Colsmann, Alexander

    2015-10-01

    We present multi-photon OLEDs where enhanced light emission was achieved by stacking two OLEDs utilizing a regular device architecture (top cathode) and an intermediate charge carrier generation layer (CGL) for monolithic device interconnection. With respect to future printing processes for organic optoelectronic devices, all functional layers were deposited from solution. The CGL comprises a low-work function zinc oxide layer that was applied from solution under ambient conditions and at moderate processing temperatures and a high-work function interlayer that was realized from various solution processable precursor-based metal oxides, like molybdenum-, vanadium- and tungsten-oxide. Since every injected electron-hole pair generates two photons, the luminance and the current efficiency of the tandem OLED at a given device current are doubled while the power efficiency remains constant. At a given luminance, the lower operating current in the tandem device reduces electrical stress and improves the device life-time. ToF-SIMS, TEM/FIB and EDX analyses provided evidence of a distinct layer sequence without intermixing upon solution deposition.

  12. Ammonia chemical ionization tandem mass spectrometry in structural determination of alkaloids.

    E-print Network

    Ammonia chemical ionization tandem mass spectrometry in structural determination of alkaloids. II 7 June 2001 Chemical ionization tandem mass spectrometry (CI-MS/MS) of alkaloids with ammonia alkaloids in extracts from six pseudomyrmecine ants of the genus Tetraponera. The MS/MS techniques along

  13. 47 CFR 69.713 - Common line, traffic-sensitive, and tandem-switched transport services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-switched transport services. 69.713 Section 69.713 Telecommunication FEDERAL COMMUNICATIONS COMMISSION..., traffic-sensitive, and tandem-switched transport services. (a) Scope. This paragraph governs requests for...)(2) of this chapter. (3) The traffic-sensitive components of tandem-switched transport services,...

  14. Tandem Time-of-Flight Mass Spectrometer for Photodissociation of Biopolymer Ions

    E-print Network

    Kim, Myung Soo

    Tandem Time-of-Flight Mass Spectrometer for Photodissociation of Biopolymer Ions Generated A tandem time-of-flight mass spectrometer for the study of photodissociation of biopolymer ions generated unimolecularly during its flight to the detector, which is called the metastable ion decomposition (MID) [4

  15. 47 CFR 69.713 - Common line, traffic-sensitive, and tandem-switched transport services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Common line, traffic-sensitive, and tandem-switched transport...Flexibility § 69.713 Common line, traffic-sensitive, and tandem-switched transport...and 69.154. (2) Services in the traffic-sensitive basket, as described...

  16. Tandem Catalysis A Highly Efficient and Rapid Approach to Synthetic Elaboration

    E-print Network

    Stoltz, Brian M.

    is transformed sequentially. A B Catalyst X Mechanism I C Mechanism II Catalyst Y Auto-tandem catalysis Mechanism I C Mechanism II Catalyst Y A Catalyst X Mechanism I Mechanism II Catalyst Y A C NH2 O HRh catalysis 3.) Auto-tandem catalysis A.) Increasing efficency in palladium catalysed reactions B.) Samarium

  17. Laboratory Exercises DNA Fingerprint Analysis of Three Short Tandem Repeat (STR)

    E-print Network

    Love, John J.

    Laboratory Exercises DNA Fingerprint Analysis of Three Short Tandem Repeat (STR) Loci State University, San Diego, California 92182-1030 We have devised and implemented a DNA fingerprinting and education. Keywords: DNA fingerprinting, forensic science, genomic DNA, PCR, short tandem repeat (STR) loci

  18. Semi-transparent perovskite solar cells for tandems with silicon and CIGS

    E-print Network

    McGehee, Michael

    Semi-transparent perovskite solar cells for tandems with silicon and CIGS Colin D. Bailie,a M on top to make a tandem solar cell. We use a transparent silver nanowire electrode on perovskite solar in efficiency over the bottom cell alone. This work paves the way for integrating perovskites into a low

  19. [Large tandem repeats of mesocricetus a uratus in silico and in situ].

    PubMed

    Miheev, D Yu; Podgornaya, O I; Ostromyshenskii, D I

    2015-01-01

    The class of tandemly repeated sequences exists only in eukaryotic genomes and absent in prokaryotes. The tens percent of eukaryotic genome are built up of the tandem repeats. The whole set of different tandem repeats is not revealed to any of the eukaryote species in spite of the half century history of its investigation by molecular biology methods. Previously we found the set of tandem repeats in the database of well assembled mouse genome with the bioinformatics methods. In the current work we applied the same methods to the poorly assembled hamster Mesocricetus auratus genome. 19 tandem repeats families have been found in hamster genome by bioinformatics (in silico). Only one of tandem repeats' families found have been cloned previously and exists in the Repbase, the database of all known repetitive fragments. The rest of the families are new and need the experimental verification by FISH (in situ). Oligo probes were designed at the base of in silico found sequences. Oligo probe for the known tandem repeat gives the same signal as the cloned probe, i.e., probes designed are suitable for oligo-FISH. All four oligo probes tested give signal at the heterochromatic centromeric region as expected, though with different intensities and at different number of chromosomes. The results show the power of the in silico methods for the mostly mysterious genome component, tandem repeats, investigation. PMID:26035966

  20. Single and Tandem Axial p-i-n Nanowire Photovoltaic Devices

    E-print Network

    Xie, Xiaoliang Sunney

    Single and Tandem Axial p-i-n Nanowire Photovoltaic Devices Thomas J. Kempa,, Bozhi Tian,, Dong Rip-i-n+-p+-i-n silicon nanowire (SiNW) photovoltaic elements. Scanning electron microscopy images of selectively etched. Finally, a novel single SiNW tandem solar cell consisting of synthetic integration of two photovoltaic

  1. Simulation of Two Dimensional Electrophoresis and Tandem Mass Spectrometry for Teaching Proteomics

    ERIC Educational Resources Information Center

    Fisher, Amanda; Sekera, Emily; Payne, Jill; Craig, Paul

    2012-01-01

    In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations--2D electrophoresis and tandem mass spectrometry.…

  2. Studies in tandem mirror theory. Paper IAEA-CN-38/F-4

    SciTech Connect

    Baldwin, D.E.; Cohen, R.H.; Cutler, T.A.

    1980-06-02

    This paper discusses the formation, maintenance, and microstability of thermal barriers, which have been introduced as a means for improving tandem mirror reactor performance at reduced technological demands. It also describes calculations of tandem mirror central-cell ..beta.. limits due to MHD ballooning modes.

  3. Comparative analysis of tandem repeats from hundreds of species reveals unique insights into centromere evolution

    PubMed Central

    2013-01-01

    Background Centromeres are essential for chromosome segregation, yet their DNA sequences evolve rapidly. In most animals and plants that have been studied, centromeres contain megabase-scale arrays of tandem repeats. Despite their importance, very little is known about the degree to which centromere tandem repeats share common properties between different species across different phyla. We used bioinformatic methods to identify high-copy tandem repeats from 282 species using publicly available genomic sequence and our own data. Results Our methods are compatible with all current sequencing technologies. Long Pacific Biosciences sequence reads allowed us to find tandem repeat monomers up to 1,419 bp. We assumed that the most abundant tandem repeat is the centromere DNA, which was true for most species whose centromeres have been previously characterized, suggesting this is a general property of genomes. High-copy centromere tandem repeats were found in almost all animal and plant genomes, but repeat monomers were highly variable in sequence composition and length. Furthermore, phylogenetic analysis of sequence homology showed little evidence of sequence conservation beyond approximately 50 million years of divergence. We find that despite an overall lack of sequence conservation, centromere tandem repeats from diverse species showed similar modes of evolution. Conclusions While centromere position in most eukaryotes is epigenetically determined, our results indicate that tandem repeats are highly prevalent at centromeres of both animal and plant genomes. This suggests a functional role for such repeats, perhaps in promoting concerted evolution of centromere DNA across chromosomes. PMID:23363705

  4. A MAX-ALGEBRA APPROACH TO MODELING AND SIMULATION OF TANDEM QUEUEING SYSTEMS

    E-print Network

    Krivulin, Nikolai K.

    A MAX-ALGEBRA APPROACH TO MODELING AND SIMULATION OF TANDEM QUEUEING SYSTEMS Nikolai K. Krivulin St.Petersburg State University Abstract. Max-algebra models of tandem single-server queueing systems with both finite of queueing systems, algebra models arise naturally from the recursive equations of the Lindley type, which

  5. THE DESIGN, OPTIMIZATION AND TESTING OF Y CHROMOSOME SHORT TANDEM REPEAT

    E-print Network

    THE DESIGN, OPTIMIZATION AND TESTING OF Y CHROMOSOME SHORT TANDEM REPEAT MEGAPLEXES by Richard THE DESIGN, OPTIMIZATION AND TESTING OF Y CHROMOSOME SHORT TANDEM REPEAT MEGAPLEXES BY Richard Schoske ABSTRACT A multiplex polymerase chain reaction (PCR) assay capable of the simultaneous amplifying 20 Y

  6. Tandem Repeat Stability in Escherichia coli O157:H7 is Dependent on Environmental Stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multilocus variable number tandem repeat analysis (MLVA) is used for source tracking Escherichia coli O157:H7 in agricultural environments. Tandem repeats were stable after limited replication, but changed after irradiation, elevated temperatures and starvation conditions. Plasmid, pO157, was lost ...

  7. Negotiation of Meaning and Corrective Feedback in Japanese/English eTandem

    ERIC Educational Resources Information Center

    Bower, Jack; Kawaguchi, Satomi

    2011-01-01

    This paper presents a comparative analysis of corrective feedback provided by participants in an eTandem interaction between university students in Japan and Australia who were learning each other's language. Corrective feedback provided to tandem partners during interaction via text-based Synchronous Computer Mediated Communication (SCMC) is…

  8. Comparative analysis of tandem repeats from hundreds of species reveals unique insights into centromere evolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Centromeres are essential for chromosome segregation, yet their DNA sequences evolve rapidly. In most animals and plants that have been studied, centromeres contain megabase-scale arrays of tandem repeats. Despite their importance, very little is known about the degree to which centromere tandem r...

  9. Comparative analysis of tandem repeats from hundreds of species reveals unique insights into centromere evolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Centromeres are essential for chromosome segregation, yet their DNA sequences evolve rapidly. In most animals and plants that have been studied, centromeres comprise of megabase-scale arrays of tandem repeats. The true prevalence of centromere tandem repeats, and whether they exhibit conserved seque...

  10. Functional divergence in tandemly duplicated Arabidopsis thaliana trypsin inhibitor genes.

    PubMed Central

    Clauss, M J; Mitchell-Olds, T

    2004-01-01

    In multigene families, variation among loci and alleles can contribute to trait evolution. We explored patterns of functional and genetic variation in six duplicated Arabidopsis thaliana trypsin inhibitor (ATTI) loci. We demonstrate significant variation in constitutive and herbivore-induced transcription among ATTI loci that show, on average, 65% sequence divergence. Significant variation in ATTI expression was also found between two molecularly defined haplotype classes. Population genetic analyses for 17 accessions of A. thaliana showed that six ATTI loci arranged in tandem within 10 kb varied 10-fold in nucleotide diversity, from 0.0009 to 0.0110, and identified a minimum of six recombination events throughout the tandem array. We observed a significant peak in nucleotide and indel polymorphism spanning ATTI loci in the interior of the array, due primarily to divergence between the two haplotype classes. Significant deviation from the neutral equilibrium model for individual genes was interpreted within the context of intergene linkage disequilibrium and correlated patterns of functional differentiation. In contrast to the outcrosser Arabidopsis lyrata for which recombination is observed even within ATTI loci, our data suggest that response to selection was slowed in the inbreeding, annual A. thaliana because of interference among functionally divergent ATTI loci. PMID:15082560

  11. Compartmentalization of Incompatible Catalytic Transformations for Tandem Catalysis.

    PubMed

    Lu, Jie; Dimroth, Jonas; Weck, Marcus

    2015-10-14

    In Nature, incompatible catalytic transformations are being carried out simultaneously through compartmentalization that allows for the combination of incompatible catalysts in tandem reactions. Herein, we take the compartmentalization concept to the synthetic realm and present an approach that allows two incompatible transition metal catalyzed transformations to proceed in one pot in tandem. The key is the site isolation of both catalysts through compartmentalization using a core-shell micellar support in an aqueous environment. The support is based on amphiphilic triblock copolymers of poly(2-oxazoline)s with orthogonal functional groups on the side chain that can be used to cross-link covalently the micelle and to conjugate two metal catalysts in different domains of the micelle. The micelle core and shell provide different microenvironments for the transformations: Co-catalyzed hydration of an alkyne proceeds in the hydrophobic core, while the Rh-catalyzed asymmetric transfer hydrogenation of the intermediate ketone into a chiral alcohol occurs in the hydrophilic shell. PMID:26426145

  12. RepeatsDB: a database of tandem repeat protein structures

    PubMed Central

    Di Domenico, Tomás; Potenza, Emilio; Walsh, Ian; Gonzalo Parra, R.; Giollo, Manuel; Minervini, Giovanni; Piovesan, Damiano; Ihsan, Awais; Ferrari, Carlo; Kajava, Andrey V.; Tosatto, Silvio C.E.

    2014-01-01

    RepeatsDB (http://repeatsdb.bio.unipd.it/) is a database of annotated tandem repeat protein structures. Tandem repeats pose a difficult problem for the analysis of protein structures, as the underlying sequence can be highly degenerate. Several repeat types haven been studied over the years, but their annotation was done in a case-by-case basis, thus making large-scale analysis difficult. We developed RepeatsDB to fill this gap. Using state-of-the-art repeat detection methods and manual curation, we systematically annotated the Protein Data Bank, predicting 10 745 repeat structures. In all, 2797 structures were classified according to a recently proposed classification schema, which was expanded to accommodate new findings. In addition, detailed annotations were performed in a subset of 321 proteins. These annotations feature information on start and end positions for the repeat regions and units. RepeatsDB is an ongoing effort to systematically classify and annotate structural protein repeats in a consistent way. It provides users with the possibility to access and download high-quality datasets either interactively or programmatically through web services. PMID:24311564

  13. Bifacial Si Heterojunction-Perovskite Organic-Inorganic Tandem to Produce Highly Efficient Solar Cell

    E-print Network

    Asadpour, Reza; Khan, M Ryyan; Alam, Muhammad A

    2015-01-01

    As single junction thin-film technologies, both Si heterojunction (HIT) and Perovskite based solar cells promise high efficiencies at low cost. One expects that a tandem cell design with these cells connected in series will improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics, however, we find that a traditional series connected tandem design suffers from low Jsc due to band-gap mismatch and current matching constraints. It requires careful thickness optimization of Perovskite to achieve any noticeable efficiency gain. Specifically, a traditional tandem cell with state-of-the-art HIT (24%) and Perovskite (20%) sub-cells provides only a modest tandem efficiency of ~25%. Instead, we demonstrate that a bifacial HIT/Perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration, the same state-of the-art sub-cells achieve a normalized output of 33%, exceed...

  14. GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects

    SciTech Connect

    Zolper, J.C.; Klem, J.F.; Plut, T.A.; Tigges, C.P.

    1995-01-01

    We report a new approach to tunnel junctions that employs a pseudomorphic GaAsSb layer to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling. Since the majority of the band offset between GaAsSb and InGaAs or InAlAs is in the valence band, when an GaAsSb layer is placed at an InGaAs or InAlAs p-n junction the tunneling distance is reduced and the tunneling current is increased. For all doping levels studied, the presence of the GaAsSb-layer enhanced the forward tunneling characteristics. In fact, in a InGaAs/GaAsSb tunnel diode a peak tunneling current sufficient for a 1000 sun intercell interconnect was achieved with p = 1.5{times}l0{sup 18} cm{sup -3} while a similarly doped all-InGaAs diode was rectifying. This approach affords a new degree of freedom in designing tunnel junctions for tandem solar cell interconnects. Previously only doping levels could be varied to control the tunneling properties. Our approach relaxes the doping requirements by employing a GaAsSb-based heterojunction.

  15. The tandem repeats enabling reversible switching between the two phases of ?-lactamase substrate spectrum.

    PubMed

    Yi, Hyojeong; Song, Han; Hwang, Junghyun; Kim, Karan; Nierman, William C; Kim, Heenam Stanley

    2014-09-01

    Expansion or shrinkage of existing tandem repeats (TRs) associated with various biological processes has been actively studied in both prokaryotic and eukaryotic genomes, while their origin and biological implications remain mostly unknown. Here we describe various duplications (de novo TRs) that occurred in the coding region of a ?-lactamase gene, where a conserved structure called the omega loop is encoded. These duplications that occurred under selection using ceftazidime conferred substrate spectrum extension to include the antibiotic. Under selective pressure with one of the original substrates (amoxicillin), a high level of reversion occurred in the mutant ?-lactamase genes completing a cycle back to the original substrate spectrum. The de novo TRs coupled with reversion makes a genetic toggling mechanism enabling reversible switching between the two phases of the substrate spectrum of ?-lactamases. This toggle exemplifies the effective adaptation of de novo TRs for enhanced bacterial survival. We found pairs of direct repeats that mediated the DNA duplication (TR formation). In addition, we found different duos of sequences that mediated the DNA duplication. These novel elements-that we named SCSs (same-strand complementary sequences)-were also found associated with ?-lactamase TR mutations from clinical isolates. Both direct repeats and SCSs had a high correlation with TRs in diverse bacterial genomes throughout the major phylogenetic lineages, suggesting that they comprise a fundamental mechanism shaping the bacterial evolution. PMID:25233343

  16. Confirmation and quantification of clenbuterol in horse urine using liquid chromatography tandem mass spectrometry triple quadrupole.

    PubMed

    Bishop, Jennifer; Heffron, Brendan; Taddei, Lisa; Benoit, Marc; Hurt, Laura; Costello, Sara; Gross, Melissa; Negrusz, Adam

    2015-03-01

    Clenbuterol (CLE) is used in horses as a bronchodilator and for its anabolic steroid-like effects. CLE is a Class 3 drug according to current Association of Racing Commissioners International (ARCI) Uniform Classification Guidelines. The Racing Medication and Testing Consortium recommended a urine CLE threshold of 140 pg/mL after careful scientific review of the results of studies describing the disposition of CLE in the horse and this threshold was adopted by the ARCI. Enzyme-linked immunosorbent assay was previously used to screen samples for CLE in Illinois, but could not detect such low concentrations in urine. Thus, a liquid-liquid extraction of CLE from urine followed by quantification by liquid chromatography-tandem mass spectrometry was developed and validated. Method validation included testing stability, ion suppression and enhancement, precision, accuracy and uncertainty. Intra-, interday and total precision and accuracy were calculated for each control and found to be within the ±15% acceptance range. The Guide to the Expression of Uncertainty in Measurement approach was used to calculate uncertainty, which was 11% at the 95% confidence level. In the past 5 years, only 15 samples were reported as positive for CLE in Illinois. This new method was used in a pilot program to screen and confirm samples received from thoroughbred and harness horses. PMID:25505053

  17. Engineering validamycin production by tandem deletion of ?-butyrolactone receptor genes in Streptomyces hygroscopicus 5008.

    PubMed

    Tan, Gao-Yi; Peng, Yao; Lu, Chenyang; Bai, Linquan; Zhong, Jian-Jiang

    2015-03-01

    Paired homologs of ?-butyrolactone (GBL) biosynthesis gene afsA and GBL receptor gene arpA are located at different positions in genome of Streptomyces hygroscopicus 5008. Inactivation of afsA homologs dramatically decreased biosynthesis of validamycin, an important anti-fungal antibiotic and a critical substrate for antidiabetic drug synthesis, and the deletion of arpA homologs increased validamycin production by 26% (?shbR1) and 20% (?shbR3). By double deletion, the ?shbR1/R3 mutant showed higher transcriptional levels of adpA-H (the S. hygroscopicus ortholog of the global regulatory gene adpA) and validamycin biosynthetic genes, and validamycin production increased by 55%. Furthermore, by engineering a high-producing industrial strain via tandem deletion of GBL receptor genes, validamycin production and productivity were enhanced from 19 to 24 g/L (by 26%) and from 6.7 to 9.7 g/L(-1) d(-1) (by 45%), respectively, which was the highest ever reported. The strategy demonstrated here may be useful to engineering other Streptomyces spp. with multiple pairs of afsA-arpA homologs. PMID:25527439

  18. Tandem Spinach Array for mRNA Imaging in Living Bacterial Cells

    PubMed Central

    Zhang, Jichuan; Fei, Jingyi; Leslie, Benjamin J.; Han, Kyu Young; Kuhlman, Thomas E.; Ha, Taekjip

    2015-01-01

    Live cell RNA imaging using genetically encoded fluorescent labels is an important tool for monitoring RNA activities. A recently reported RNA aptamer-fluorogen system, the Spinach, in which an RNA aptamer binds and induces the fluorescence of a GFP-like 3,5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI) ligand, can be readily tagged to the RNA of interest. Although the aptamer–fluorogen system is sufficient for imaging highly abundant non-coding RNAs (tRNAs, rRNAs, etc.), it performs poorly for mRNA imaging due to low brightness. In addition, whether the aptamer-fluorogen system may perturb the native RNA characteristics has not been systematically characterized at the levels of RNA transcription, translation and degradation. To increase the brightness of these aptamer-fluorogen systems, we constructed and tested tandem arrays containing multiple Spinach aptamers (8–64 aptamer repeats). Such arrays enhanced the brightness of the tagged mRNA molecules by up to ~17 fold in living cells. Strong laser excitation with pulsed illumination further increased the imaging sensitivity of Spinach array-tagged RNAs. Moreover, transcriptional fusion to the Spinach array did not affect mRNA transcription, translation or degradation, indicating that aptamer arrays might be a generalizable labeling method for high-performance and low-perturbation live cell RNA imaging. PMID:26612428

  19. Focused tandem shock waves in water and their potential application in cancer treatment

    NASA Astrophysics Data System (ADS)

    Lukes, P.; Sunka, P.; Hoffer, P.; Stelmashuk, V.; Pouckova, P.; Zadinova, M.; Zeman, J.; Dibdiak, L.; Kolarova, H.; Tomankova, K.; Binder, S.; Benes, J.

    2014-01-01

    The generator of two focused successive (tandem) shock waves (FTSW) in water produced by underwater multichannel electrical discharges at two composite electrodes, with a time delay between the first and second shock waves of 10 s, was developed. It produces, at the focus, a strong shock wave with a peak positive pressure of up to 80 MPa, followed by a tensile wave with a peak negative pressure of up to MPa, thus generating at the focus a large amount of cavitation. Biological effects of FTSW were demonstrated in vitro on hemolysis of erythrocytes and cell viability of human acute lymphoblastic leukemia cells as well as on tumor growth delay ex vivo and in vivo experiments performed with B16 melanoma, T-lymphoma, and R5-28 sarcoma cell lines. It was demonstrated in vivo that FTSW can enhance antitumor effects of chemotherapeutic drugs, such as cisplatin, most likely due to increased permeability of the membrane of cancer cells induced by FTSW. Synergetic cytotoxicity of FTSW with sonosensitive porphyrin-based drug Photosan on tumor growth was observed, possibly due to the cavitation-induced sonodynamic effect of FTSW.

  20. Tandem Spinach Array for mRNA Imaging in Living Bacterial Cells.

    PubMed

    Zhang, Jichuan; Fei, Jingyi; Leslie, Benjamin J; Han, Kyu Young; Kuhlman, Thomas E; Ha, Taekjip

    2015-01-01

    Live cell RNA imaging using genetically encoded fluorescent labels is an important tool for monitoring RNA activities. A recently reported RNA aptamer-fluorogen system, the Spinach, in which an RNA aptamer binds and induces the fluorescence of a GFP-like 3,5-difluoro-4-hydroxybenzylidene imidazolinone (DFHBI) ligand, can be readily tagged to the RNA of interest. Although the aptamer-fluorogen system is sufficient for imaging highly abundant non-coding RNAs (tRNAs, rRNAs, etc.), it performs poorly for mRNA imaging due to low brightness. In addition, whether the aptamer-fluorogen system may perturb the native RNA characteristics has not been systematically characterized at the levels of RNA transcription, translation and degradation. To increase the brightness of these aptamer-fluorogen systems, we constructed and tested tandem arrays containing multiple Spinach aptamers (8-64 aptamer repeats). Such arrays enhanced the brightness of the tagged mRNA molecules by up to ~17 fold in living cells. Strong laser excitation with pulsed illumination further increased the imaging sensitivity of Spinach array-tagged RNAs. Moreover, transcriptional fusion to the Spinach array did not affect mRNA transcription, translation or degradation, indicating that aptamer arrays might be a generalizable labeling method for high-performance and low-perturbation live cell RNA imaging. PMID:26612428

  1. Acoustics and Surface Pressure Measurements from Tandem Cylinder Configurations

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, Thomas F.; Lockard, David P.; Choudhari, Meelan M.; Stead, Daniel J.

    2014-01-01

    Acoustic and unsteady surface pressure measurements from two cylinders in tandem configurations were acquired to study the effect of spacing, surface trip and freestream velocity on the radiated noise. The Reynolds number ranged from 1.15x10(exp 5) to 2.17x10(exp 5), and the cylinder spacing varied between 1.435 and 3.7 cylinder diameters. The acoustic and surface pressure spectral characteristics associated with the different flow regimes produced by the cylinders' wake interference were identified. The dependence of the Strouhal number, peak Sound Pressure Level and spanwise coherence on cylinder spacing and flow velocity was examined. Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the largest and smallest cylinder spacing tested.

  2. Physics issues in mirror and tandem mirror systems

    SciTech Connect

    Post, R.F.

    1984-06-15

    Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed.

  3. ''Moderate-m'' ballooning modes in quadrapole stabilized tandem mirrors

    SciTech Connect

    Nevins, W.M.; Pearlstein, L.D.

    1988-07-01

    The beta limits on the central cells of nonaxisymmetric tandem mirrors due to moderate-m ballooning modes are studied. Both finite Larmor radius (FLR) effects and corrections associated with the finite extent of the ballooning modes in the plane perpendicular to B are retained. The assumption of short perpendicular wavelength together with the large ellipticity of the flux surfaces near the magnetohydrodynamic (MHD) anchor cells allows a reduction of the three-dimensional problem into a sequence of three one-dimensional problems. The marginal stable boundary for the Mirror Fusion Test Facility (MFTF-B) (National Technical Information Service Document Nos. 82020108 and UCID-19359) is calculated and compared with that obtained from a low mode number calculation.

  4. Identification of Tandem Mass Spectra of Mixtures of Isomeric Peptides

    PubMed Central

    Chen, Xi; Drogaris, Paul; Bern, Marshall

    2010-01-01

    Shotgun proteomics separates peptides by chromatography and precursor mass over charge, yet in almost any large data set of a complex sample there will be some tandem mass spectra containing more than one peptide. These mixture spectra contain two co-eluting peptides with close precursor mass over charge, and sometimes contain exact isomers, often the same peptide with the same modification in two different positions. Isomers present a problem when the position of the modification is of special interest, as in histone modification studies or “oxidative footprinting” studies of protein structure. Here we give algorithms for identifying isomeric mixtures, and present results on two different histones and four oxidative footprinting targets. Five of the six targets contain at least one peptide that appears in isomeric mixtures, but in none of the cases are mixtures so prevalent that they greatly impact the overall identification rate. PMID:20329787

  5. Tandem synthesis of alternating polyesters from renewable resources

    PubMed Central

    Robert, Carine; de Montigny, Frédéric; Thomas, Christophe M.

    2011-01-01

    The vast majority of commodity materials are obtained from petrochemical feedstocks. These resources will plausibly be depleted within the next 100 years, and the peak in global oil production is estimated to occur within the next few decades. In this regard, biomass represents an abundant carbon-neutral renewable resource for the production of polymers. Here we report a new strategy, based on tandem catalysis, to obtain renewable materials. Commercially available complexes are found to be efficient catalysts for alternating polyesters from the cyclization of dicarboxylic acids followed by alternating copolymerization of the resulting anhydrides with epoxides. This operationally simple method is an attractive strategy for the production of new biodegradable polyesters. PMID:22158441

  6. Total synthesis of (+)-chinensiolide B via tandem allylboration/lactonization.

    PubMed

    Elford, Tim G; Hall, Dennis G

    2010-02-10

    The chinensiolides are a family of guaiane type alpha-methylene gamma-lactone natural products recently isolated from Ixeris chinensis Nakai, a plant used in Chinese folk medicine. The first enantioselective total synthesis of (+)-chinensiolide B was accomplished in 15 steps for the longest linear sequence with an overall yield of 6.7% starting from inexpensive and readily available (R)-carvone. A highly stereoselective and E/Z-selective tandem allylboration/lactonization reaction between two highly functionalized partners was exploited as a key step. The synthesis also highlights several solutions to chemoselectivity issues arising from the reactive alpha-methylene gamma-lactone. For instance, a ring-closing metathesis formed the requisite seven-membered ring in a chemoselective fashion while avoiding the reactivity of the conjugated alpha-methylene unit. PMID:20067261

  7. Configuration and layout of the tandem mirror Fusion Power Demonstrator

    SciTech Connect

    Clarkson, I.R.; Neef, W.S.

    1983-11-30

    Studies have been performed during the past year to determine the configuration of a tandem mirror Fusion Power Demonstrator (FPD) machine capable of producing 1750 MW of fusion power. The FPD is seen as the next logical step after the Mirror Fusion Test Facility-B (MFTF-B) toward operation of a power reactor. The design of the FPD machine allows a phased construction: Phase I, a hydrogen or deuterium checkout machine; Phase 2, a DT breakeven machine; Phase 3, development of the Phase 2 machine to provide net power and act as a reactor demonstrator. These phases are essential to the development of remote handling equipment and the design of components that will ultimately be remotely handled. Phasing also permits more modes funding early in the program with some costs committed only after reaching major milestones.

  8. Modification of the argon stripping target of the tandem accelerator.

    PubMed

    Makarov, A; Ostreinov, Yu; Taskaev, S; Vobly, P

    2015-12-01

    The tandem accelerator with vacuum insulation has been proposed and developed in Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1MV potential of the high-voltage electrode, converted into protons in the gas stripping target inside the electrode, and then protons are accelerated again by the same potential. A stationary proton beam with 2MeV energy, 1.6mA current, 0.1% energy monochromaticity, and 0.5% current stability is obtained now. To conduct Boron Neutron Capture Therapy it is planned to increase the proton beam current to at least 3mA. The paper presents the results of experimental studies clarifying the reasons for limiting the current, and gives suggestions for modifying the gas stripping target in order to increase the proton beam current along with the stability of the accelerator. PMID:26242555

  9. Characterization of plant polyadenylation complexes by using tandem affinity purification.

    PubMed

    Zhao, Hongwei; Ye, Xinfu; Li, Qingshun Quinn

    2015-01-01

    Messenger RNA in eukaryotic cells is initially produced as a nascent transcript (pre-mRNA) without a polyadenine [poly(A)] tail to the 3' end. The precise cleavage of the pre-mRNA and addition of a poly(A) track need the communication between cis-elements in the pre-mRNA sequences and transacting protein factors recognizing them. Based on homology analyses, Arabidopsis cleavage and polyadenylation specificity factor (AtCPSF) complex should play a critical role in pre-mRNA 3' end processing. Here we describe the isolation of AtCPSF complex by using a tandem affinity purification (TAP) method. We demonstrate that TAP is a potent protein complex isolating approach that can fulfill a downstream protein identification purpose based on mass spectrometry techniques. PMID:25487205

  10. Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

    NASA Astrophysics Data System (ADS)

    Oliva, Jorge; Papadimitratos, Alexios; Desirena, Haggeo; De la Rosa, Elder; Zakhidov, Anvar A.

    2015-11-01

    Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process.

  11. DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Chaban, Galina M.; Wang, Dunyou; Dateo, Christopher E.

    2005-01-01

    Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported.

  12. Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Dziendziel, Randolph J. (Middle Grove, NY); Baldasaro, Paul F. (Clifton Park, NY); DePoy, David M. (Clifton Park, NY)

    2010-09-07

    This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

  13. Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Dziendziel, Randolph J. (Middle Grove, NY); DePoy, David Moore (Clifton Park, NY); Baldasaro, Paul Francis (Clifton Park, NY)

    2007-01-23

    This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

  14. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, Edward J. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY); Dziendziel, Randolph J. (Middlegrove, NY)

    1997-01-01

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.IF ; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5.lambda..sub.IF.

  15. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, E.J.; Baldasaro, P.F.; Dziendziel, R.J.

    1997-12-23

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength {lambda}{sub IF} approximately equal to the bandgap wavelength {lambda}{sub g} of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5{lambda}{sub IF} to {lambda}{sub IF} and reflect from {lambda}{sub IF} to about 2{lambda}{sub IF}; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5{lambda}{sub IF}. 10 figs.

  16. Radical-driven peptide backbone dissociation tandem mass spectrometry.

    PubMed

    Oh, Han Bin; Moon, Bongjin

    2015-01-01

    In recent years, a number of novel tandem mass spectrometry approaches utilizing radical-driven peptide gas-phase fragmentation chemistry have been developed. These approaches show a peptide fragmentation pattern quite different from that of collision-induced dissociation (CID). The peptide fragmentation features of these approaches share some in common with electron capture dissociation (ECD) or electron transfer dissociation (ETD) without the use of sophisticated equipment such as a Fourier-transform mass spectrometer. For example, Siu and coworkers showed that CID of transition metal (ligand)-peptide ternary complexes led to the formation of peptide radical ions through dissociative electron transfer (Chu et al., 2000. J Phys Chem B 104:3393-3397). The subsequent collisional activation of the generated radical ions resulted in a number of characteristic product ions, including a, c, x, z-type fragments and notable side-chain losses. Another example is the free radical initiated peptide sequencing (FRIPS) approach, in which Porter et al. and Beauchamp et al. independently introduced a free radical initiator to the primary amine group of the lysine side chain or N-terminus of peptides (Masterson et al., 2004. J Am Chem Soc 126:720-721; Hodyss et al., 2005 J Am Chem Soc 127: 12436-12437). Photodetachment of gaseous multiply charged peptide anions (Joly et al., 2008. J Am Chem Soc 130:13832-13833) and UV photodissociation of photolabile radical precursors including a C-I bond (Ly & Julian, 2008. J Am Chem Soc 130:351-358; Ly & Julian, 2009. J Am Soc Mass Spectrom 20:1148-1158) also provide another route to generate radical ions. In this review, we provide a brief summary of recent results obtained through the radical-driven peptide backbone dissociation tandem mass spectrometry approach. PMID:24863492

  17. Calcium channel blocker verapamil enhances endoplasmic reticulum stress and cell death induced by proteasome inhibition in myeloma cells.

    PubMed

    Meister, Silke; Frey, Benjamin; Lang, Veronika R; Gaipl, Udo S; Schett, Georg; Schlötzer-Schrehardt, Ursula; Voll, Reinhard E

    2010-07-01

    The proteasome inhibitor bortezomib is clinically approved for the treatment of multiple myeloma. However, long-term remissions are difficult to achieve, and myeloma cells often develop secondary resistance to proteasome inhibitors. We recently demonstrated that the extraordinary sensitivity of myeloma cells toward bortezomib is dependent on their extensive immunoglobulin synthesis, thereby triggering the terminal unfolded protein response (UPR). Here, we investigated whether verapamil, an inhibitor of the multidrug resistance (MDR) gene product, can enhance the cytotoxicity of bortezomib. The combination of bortezomib and verapamil synergistically decreased the viability of myeloma cells by inducing cell death. Importantly, bortezomib-mediated activation of major UPR components was enhanced by verapamil. The combination of bortezomib and verapamil resulted in caspase activation followed by poly(ADP-ribose) polymerase cleavage, whereas nuclear factor kappaB (NF-kappaB) activity declined in myeloma cells. Also, we found reduced immunoglobulin G secretion along with increased amounts of ubiquitinylated proteins within insoluble fractions of myeloma cells when using the combination treatment. Verapamil markedly induced reactive oxygen species production and autophagic-like processes. Furthermore, verapamil decreased MDR1 expression. We conclude that verapamil increased the antimyeloma effect of bortezomib by enhancing ER stress signals along with NF-kappaB inhibition, leading to cell death. Thus, the combination of bortezomib with verapamil may improve the efficacy of proteasome inhibitory therapy. PMID:20651984

  18. An approach for configuring space photovoltaic tandem arrays based on cell layer performance

    NASA Technical Reports Server (NTRS)

    Flora, C. S.; Dillard, P. A.

    1991-01-01

    Meeting solar array performance goals of 300 W/Kg requires use of solar cells with orbital efficiencies greater than 20 percent. Only multijunction cells and cell layers operating in tandem produce this required efficiency. An approach for defining solar array design concepts that use tandem cell layers involve the following: transforming cell layer performance at standard test conditions to on-orbit performance; optimizing circuit configuration with tandem cell layers; evaluating circuit sensitivity to cell current mismatch; developing array electrical design around selected circuit; and predicting array orbital performance including seasonal variations.

  19. Tandem bis-aza-Michael addition reaction of amines in aqueous medium promoted by polystyrenesulfonic Acid

    EPA Science Inventory

    An efficient and environmentally benign tandem bis-aza-Michael addition of amines catalyzed by polystyrene sulfonic acid (PSSA) is described. This operationally simple high yielding microwave assisted synthetic protocol proceeded in water in the absence of any organic solvent.

  20. Progress towards the synthesis of tetracyclic heteroaromatic compounds via tandem benzannulation-cyclization strategies

    E-print Network

    Mamaliga, Galina

    2012-01-01

    A tandem benzannulation-cyclization strategy was successfully applied to the synthesis of a tetracyclic heteroaromatic compound expected to have interesting electronic properties. Benzannulation of a diazo ketone and a ...

  1. Studies of the Lateral-Directional Flying Qualities of a Tandem Helicopter in Forward Flight

    NASA Technical Reports Server (NTRS)

    Amer, Kenneth B; Tapscott, Robert J

    1954-01-01

    An investigation of the lateral-directional flying qualities of a tandem-rotor helicopter in forward flight was undertaken to determine desirable goals for helicopter lateral-directional flying qualities and possible methods of achieving these goals in the tandem-rotor helicopter. Comparison between directional stability as measured in flight and rotor-off model tests in a wind tunnel shows qualitative agreement and, hence, indicates such wind-tunnel test, despite the absence of the rotors, to be one effective method of studying means of improving the directional stability of the tandem helicopter. Flight-test measurements of turns and oscillations, in conjunction with analytical studies, suggest possible practical methods of achieving the goals of satisfactory turn and oscillatory characteristics in the tandem helicopter.

  2. Tandem benzannulation-ring closing metathesis strategy for the synthesis of benzo-fused nitrogen heterocycles ;

    E-print Network

    Mak, Xiao Yin

    2008-01-01

    A tandem benzannulation-ring closing metathesis strategy for the efficient synthesis of benzo-fused nitrogen heterocycles such as dihydroquinolines, benzazepines, and benzazocines has been developed. This strategy is based ...

  3. Progress in radiocarbon dating with the Chalk River MP tandem accelerator

    SciTech Connect

    Andrews, H.R.; Ball, G.C.; Brown, R.M.; Davies, W.G.; Imahori, Y.; Milton, J.C.D.

    1980-01-01

    The evolution of a tandem accelerator /sup 14/C dating system at Chalk River is recounted. Background problems and sources of instability are discussed and solutions are described. Details of sample chemistry and source preparation are presented.

  4. Retrotransposons and Tandem Repeat Sequences in the Nuclear Genomes of Cryptomonad Algae

    E-print Network

    Archibald, John

    ). For example, approximately 10% of the 60- megabase (Mb) genome of Trypanosoma cruzi is comprised of a 195-bp) retrotransposons and tandem repeat sequences are a prominent feature of the nuclear genomes of both organisms

  5. Synfuels from fusion: producing hydrogen with the Tandem Mirror Reactor and thermochemical cycles

    SciTech Connect

    Werner, R.W.; Ribe, F.L.

    1981-01-21

    This volume contains the following sections: (1) the Tandem Mirror fusion driver, (2) the Cauldron blanket module, (3) the flowing microsphere, (4) coupling the reactor to the process, (5) the thermochemical cycles, and (6) chemical reactors and process units. (MOW)

  6. A One-Pot Tandem Olefin Isomerization/Metathesis-Coupling (ISOMET) Reaction

    E-print Network

    Dobereiner, Graham E.

    A tandem catalytic reaction has been developed as part of a process to discover tungsten-based olefin metathesis catalysts that have a strong preference for terminal olefins over cis or trans internal isomers in olefin ...

  7. Multifunctional Coatings from Scalable Single Source Precursor Chemistry in Tandem Photoelectrochemical Water Splitting

    E-print Network

    Lai, Yi-Hsuan; Palm, David W.; Reisner, Erwin

    2015-11-24

    The straightforward and inexpensive fabrication of stabilized and activated photoelectrodes for application in tandem photoelectrochemical (PEC) water splitting is reported. Semiconductors such as Si, WO3 and BiVO4 can be coated with a composite...

  8. Fuel properties of heptadecene isomers prepared via tandem isomerization-decarboxylation of oleic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heptadecene isomers were prepared via tandem isomerization-decarboxylation of oleic acid using catalytic triruthenium dodecacarbonyl [Ru3(CO)12]. Chromatographic and spectroscopic characterization of the isolated heptadecene mixture indicated that it consisted of 96% internal isomers and 4% aromatic...

  9. Tandem Oxidative Cyclization with Rhenium Oxide. Total Synthesis of 17,18-bisepi-Goniocin

    E-print Network

    Keinan, Ehud

    Tandem Oxidative Cyclization with Rhenium Oxide. Total Synthesis of 17,18-bisepi-Goniocin Subhash C of a rhenium(VII) reagent to produce a single stereoisomer of a tris-THF product. Surprisingly, however

  10. Tandem Polymer Solar Cells Featuring a Spectrally Matched Low-Bandgap Polymer

    SciTech Connect

    Dou, L.; You, J.; Yang, J.; Chen, C. C.; He, Y.; Murase, S.; Moriarty, T.; Emery, K.; Li, G.; Yang, Y.

    2012-03-01

    Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of a suitable low-bandgap polymer. Here, we demonstrate highly efficient single and tandem polymer solar cells featuring a low-bandgap conjugated polymer (PBDTT-DPP: bandgap, {approx}1.44 eV). A single-layer device based on the polymer provides a power conversion efficiency of {approx}6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which is, to the best of our knowledge, the highest certified efficiency for a polymer solar cell to date.

  11. Design and long-term monitoring of DSC/CIGS tandem solar module

    NASA Astrophysics Data System (ADS)

    Vildanova, M. F.; Nikolskaia, A. B.; Kozlov, S. S.; Shevaleevskiy, O. I.

    2015-11-01

    This paper describes the design and development of tandem dye-sensitized/Cu(In, Ga)Se (DSC/CIGS) PV modules. The tandem PV module comprised of the top DSC module and a bottom commercial 0,8 m2 CIGS module. The top DSC module was made of 10 DSC mini-modules with the field size of 20 × 20 cm2 each. Tandem DSC/CIGS PV modules were used for providing the long-term monitoring of energy yield and electrical parameters in comparison with standalone CIGS modules under outdoor conditions. The outdoor test facility, containing solar modules of both types and a measurement unit, was located on the roof of the Institute of Biochemical Physics in Moscow. The data obtained during monitoring within the 2014 year period has shown the advantages of the designed tandem DSC/CIGS PV-modules over the conventional CIGS modules, especially for cloudy weather and low-intensity irradiation conditions.

  12. Hybrid de novo tandem repeat detection using short and long reads

    PubMed Central

    2015-01-01

    Background As one of the most studied genome rearrangements, tandem repeats have a considerable impact on genetic backgrounds of inherited diseases. Many methods designed for tandem repeat detection on reference sequences obtain high quality results. However, in the case of a de novo context, where no reference sequence is available, tandem repeat detection remains a difficult problem. The short reads obtained with the second-generation sequencing methods are not long enough to span regions that contain long repeats. This length limitation was tackled by the long reads obtained with the third-generation sequencing platforms such as Pacific Biosciences technologies. Nevertheless, the gain on the read length came with a significant increase of the error rate. The main objective of nowadays studies on long reads is to handle the high error rate up to 16%. Methods In this paper we present MixTaR, the first de novo method for tandem repeat detection that combines the high-quality of short reads and the large length of long reads. Our hybrid algorithm uses the set of short reads for tandem repeat pattern detection based on a de Bruijn graph. These patterns are then validated using the long reads, and the tandem repeat sequences are constructed using local greedy assemblies. Results MixTaR is tested with both simulated and real reads from complex organisms. For a complete analysis of its robustness to errors, we use short and long reads with different error rates. The results are then analysed in terms of number of tandem repeats detected and the length of their patterns. Conclusions Our method shows high precision and sensitivity. With low false positive rates even for highly erroneous reads, MixTaR is able to detect accurate tandem repeats with pattern lengths varying within a significant interval. PMID:26399998

  13. Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

    SciTech Connect

    Calderon, M.O.; Hunt, A.L.; Lang, D.D.; Nexsen, W.E.; Pickles, W.L.; Turner, W.C.

    1983-08-12

    The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal-barrier experiments designed to provide an improved performance for tandem-mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering system.

  14. OPTIMIZATION OF a-SiGe BASED TRIPLE, TANDEM AND SINGLE-JUNCTION SOLAR Xunming Deng

    E-print Network

    Deng, Xunming

    OPTIMIZATION OF a-SiGe BASED TRIPLE, TANDEM AND SINGLE-JUNCTION SOLAR CELLS Xunming Deng Department improvements in device fabrication, the UT group fabricated 1) triple-junction a-Si/a-SiGe/a- SiGe solar cells with 12.5% initial efficiency and 10.7% stable efficiency, tandem-junction a-Si/a-SiGe solar cells with 12

  15. Synthesis of Pyrrolidines and Pyrroles via Tandem Amination/Cyanation/Alkylation and Amination/Oxidation Sequences

    PubMed Central

    Han, Junbin; Lu, Zhichao; Hammond, Gerald B.; Xu, Bo

    2014-01-01

    Starting from a primary amine-tethered alkyne 1, a copper-catalyzed three-component tandem amination/cyanation/alkylation sequence gives ?-CN pyrrolidine 6 in good yield and regioselectivity. Also, a silver mediated tandem amination/oxidation of a secondary amine-tethered alkyne 7 produces functionalized pyrrole 8 in good yield. All reactions were conducted in one pot without any protection/deprotection steps. PMID:25386099

  16. Solution-processed white phosphorescent tandem organic light-emitting devices.

    PubMed

    Chiba, Takayuki; Pu, Yong-Jin; Kido, Junji

    2015-08-26

    Solution-processed phosphorescent tandem organic light-emitting devices (OLEDs) exhibit extremely high efficiencies (94 cd A(-1) ) and 26% external quantum efficiency (EQE) at 5000 cd m(-2) for green phosphorescent devices and 69 cd A(-1) and 28% EQE at 5000 cd m(-2) for white phosphorescent devices. Development of these highly efficient solution-processed tandem-OLEDs with inverted device structure paves the way to printable, low-cost, and large-area white lighting. PMID:26212355

  17. Tandem solar cells made from amorphous silicon and polymer bulk heterojunction sub-cells.

    PubMed

    Park, Sung Heum; Shin, Insoo; Kim, Kwang Ho; Street, Robert; Roy, Anshuman; Heeger, Alan J

    2015-01-14

    A tandem solar cell based on a combination of an amorphous silicon (a-Si) and polymer solar cell (PSC) is demonstrated. As these tandem devices can be readily fabricated by low-cost methods, they require only a minor increase in the total manufacturing cost. Therefore, a combination of a-Si and PSC provides a compelling solution to reduce the cost of electricity produced by photovoltaics. PMID:25410395

  18. Moral Enhancement

    PubMed Central

    Douglas, Thomas

    2008-01-01

    Opponents of biomedical enhancement often claim that, even if such enhancement would benefit the enhanced, it would harm others. But this objection looks unpersuasive when the enhancement in question is a moral enhancement — an enhancement that will expectably leave the enhanced person with morally better motives than she had previously. In this article I (1) describe one type of psychological alteration that would plausibly qualify as a moral enhancement, (2) argue that we will, in the medium-term future, probably be able to induce such alterations via biomedical intervention, and (3) defend future engagement in such moral enhancements against possible objections. My aim is to present this kind of moral enhancement as a counter-example to the view that biomedical enhancement is always morally impermissible. PMID:19132138

  19. On the trajectory scaling of tandem twin jets in cross-flow in close proximity

    NASA Astrophysics Data System (ADS)

    New, T. H.; Zang, B.

    2015-11-01

    An experimental study has been conducted on tandem twin jets in cross-flow (JICF) in close proximity to investigate the relationships between their trajectories, separation distances and velocity ratios. Results show that the front and rear jets, each with initially distinct jet trajectory, merge into a single trajectory shortly after they exhaust into the cross-flow. Furthermore, the merged tandem JICF attains deeper cross-flow penetration than that of a single JICF at the same velocity ratio. The front jet is also observed to provide `shielding' for the rear jet such that the latter penetrates relatively deeper into the cross-flow, which corroborates observations made by earlier studies. In particular, the present study demonstrates that it is possible to collapse the tandem JICF merged trajectories by ` rD'-scaling, where A and B coefficients show slight reductions and increments, respectively, with increasing separation distance. Collapsing the merged trajectories by using single JICF A and B coefficients leads to the notion of effective velocity ratio for tandem JICF, which enable the authors to propose a modification in the ` rD'-scaling law for tandem JICF. Lastly, the modified ` rD'-scaling law is applied to trajectory data from an earlier tandem JICF study, and its validity is demonstrated by the resulting good collapse.

  20. Ligand binding by the tandem glycine riboswitch depends on aptamer dimerization but not double ligand occupancy

    PubMed Central

    Ruff, Karen M.

    2014-01-01

    The glycine riboswitch predominantly exists as a tandem structure, with two adjacent, homologous ligand-binding domains (aptamers), followed by a single expression platform. The recent identification of a leader helix, the inclusion of which eliminates cooperativity between the aptamers, has reopened the debate over the purpose of the tandem structure of the glycine riboswitch. An equilibrium dialysis-based assay was combined with binding-site mutations to monitor glycine binding in each ligand-binding site independently to understand the role of each aptamer in glycine binding and riboswitch tertiary interactions. A series of mutations disrupting the dimer interface was used to probe how dimerization impacts ligand binding by the tandem glycine riboswitch. While the wild-type tandem riboswitch binds two glycine equivalents, one for each aptamer, both individual aptamers are capable of binding glycine when the other aptamer is unoccupied. Intriguingly, glycine binding by aptamer-1 is more sensitive to dimerization than glycine binding by aptamer-2 in the context of the tandem riboswitch. However, monomeric aptamer-2 shows dramatically weakened glycine-binding affinity. In addition, dimerization of the two aptamers in trans is dependent on glycine binding in at least one aptamer. We propose a revised model for tandem riboswitch function that is consistent with these results, wherein ligand binding in aptamer-1 is linked to aptamer dimerization and stabilizes the P1 stem of aptamer-2, which controls the expression platform. PMID:25246650

  1. Numerical analysis of the s1020 airfoils in tandem under different flapping configurations

    NASA Astrophysics Data System (ADS)

    Lim, K. B.; Tay, W. B.

    2010-05-01

    The objective of this project is to improve the performance of the efficiency, thrust and lift of flapping wings in tandem arrangement. This research investigates the effect of the arrangement of the airfoils in tandem on the performance of the airfoils by varying the phase difference and distance between the airfoils. Three flapping configurations from an earlier phase of a research which gives high efficiency, thrust and lift are used in the tandem simulation. It is found all the different flapping configurations show improvement in the efficiency, thrust or lift when the distance between the two airfoils and the phase angle between the heaving positions of the two airfoils are optimal. The average thrust coefficient of the tandem arrangement managed to attain more than twice that of the single one (4.84 vs. 2.05). On the other hand, the average lift coefficient of the tandem arrangement also increased to 4.59, as compared to the original single airfoil value of 3.04. All these results obtained will aid in the design of a better ornithopter with tandem wing arrangement.

  2. Single and Tandem Stents in Sheep Iliac Arteries: Is There a Difference in Patency?

    SciTech Connect

    Schuermann, Karl; Vorwerk, Dierk; Buecker, Arno; Grosskortenhaus, Stefanie; Guenther, Rolf W.

    1998-09-15

    Purpose: To compare patency and neointima formation of single and tandem arterial stents. Methods: In each of six sheep, two Memotherm nitinol stents (tandem stents) were inserted into the external iliac artery on one side and a single stent into the artery on the opposite side. The size of the iliac lumen was assessed in the proximal, middle, and distal segments of the stents by intravascular ultrasound (IVUS) before, immediately after, and 1 month after implantation when the sheep were killed. Neointimal thickness was determined in the proximal, middle, and distal segments of each stent by light microscopy. Results: All stents remained patent. There was no significant difference in lumen and neointimal thickness between single and tandem stents. Cranial tandem stents showed a significantly wider lumen and smaller neointimal thickness than caudal tandem stents. In the proximal and distal segments, the lumen of the stents was significantly smaller and the neointimal thickness greater than in the middle segment; differences in neointimal thickness were significant only between the proximal and the middle segment. Conclusion: In an experimental setting, tandem stents did not interfere with one another with regard to patency and neointima formation when compared with a single contralateral stent. Neointimal thickening after stent insertion seems to be inversely related to the original arterial diameter.

  3. Genome-wide computational prediction of tandem gene arrays: application in yeasts

    PubMed Central

    2010-01-01

    Background This paper describes an efficient in silico method for detecting tandem gene arrays (TGAs) in fully sequenced and compact genomes such as those of prokaryotes or unicellular eukaryotes. The originality of this method lies in the search of protein sequence similarities in the vicinity of each coding sequence, which allows the prediction of tandem duplicated gene copies independently of their functionality. Results Applied to nine hemiascomycete yeast genomes, this method predicts that 2% of the genes are involved in TGAs and gene relics are present in 11% of TGAs. The frequency of TGAs with degenerated gene copies means that a significant fraction of tandem duplicated genes follows the birth-and-death model of evolution. A comparison of sequence identity distributions between sets of homologous gene pairs shows that the different copies of tandem arrayed paralogs are less divergent than copies of dispersed paralogs in yeast genomes. It suggests that paralogs included in tandem structures are more recent or more subject to the gene conversion mechanism than other paralogs. Conclusion The method reported here is a useful computational tool to provide a database of TGAs composed of functional or nonfunctional gene copies. Such a database has obvious applications in the fields of structural and comparative genomics. Notably, a detailed study of the TGA catalog will make it possible to tackle the fundamental questions of the origin and evolution of tandem gene clusters. PMID:20092627

  4. Aerodynamics of biplane and tandem wings at low Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Jones, R.; Cleaver, D. J.; Gursul, I.

    2015-06-01

    Experiments were performed to investigate the aerodynamic characteristics of two-wing configurations at a low Reynolds number of 100,000. The wing models were rectangular flat plates with a semi-aspect ratio of two. The stagger between the wings was varied from ? X/c = 0 to 1.5; the gap was varied from ? Y/c = 0 to 2 and ? Y/c = -1.5 to 1.5 for biplane and tandem configurations, respectively, with the decalage angle fixed at 0°. Lift, drag, aerodynamic efficiency and power efficiency ratios show that for small incidence angles, performance compared with the single wing is degraded. However, for single-wing post-stall angles of attack, lift performance improves and stall is delayed significantly for many configurations with nonzero gap, i.e., ? Y/c ? 0. For a fixed angle of attack, there are optimal gaps between the wings for which total lift becomes maximum. Particle image velocimetry measurements show that performance improvement relies heavily on the strength of the inter-wing flow and the interaction of the separated shear layers from the leading edge and trailing edge of the leading wing with the trailing wing. Unsteady forces are found to intensify for certain two-wing configurations. A switching between the stalled and unstalled states for the trailing wing as well as a switching between the merged and distinct wakes is shown to have high flow unsteadiness and large lift fluctuations.

  5. Tandem Differential Mobility Analyzer/Aerodynamic Particle Sizer (APS) Handbook

    SciTech Connect

    Collins, D

    2010-06-18

    The tandem differential mobility analyzer (TDMA) is a single instrument that cycles through a series of complementary measurements of the physical properties of size-resolved submicron particles. In 2008, the TDMA was augmented through the addition of an aerodynamic particle sizer (APS), which extends the upper limit of the measured size distribution into the supermicron range. These two instruments are operated in parallel, but because they are controlled by a common computer and because the size distributions measured by the two are integrated in the produced datastreams, they are described together here. Throughout the day, the TDMA sequentially measures submicron aerosol size distributions and size-resolved hygroscopic growth distributions. More specifically, the instrument is operated as a scanning DMA to measure size distributions and as a TDMA to measure size-resolved hygroscopicity. A typical measurement sequence requires roughly 45 minutes. Each morning additional measurements are made of the relative humidity (RH) dependent hygroscopicity and temperature-dependent volatility of size-resolved particles. When the outside temperature and RH are within acceptable ranges, the hydration state of size-resolved particles is also characterized. The measured aerosol distributions complement the array of aerosol instruments in the Aerosol Observing System (AOS) and provide additional details of the light-scattering and cloud-nucleating characteristics of the aerosol.

  6. Measurements of Unsteady Wake Interference Between Tandem Cylinders

    NASA Technical Reports Server (NTRS)

    Jenkins, Luther N.; Neuhart, Dan H.; McGinley, Cahterine B.; Choudhari, Meelan M.; Khorrami, Mehdi R.

    2006-01-01

    A multi-phase, experimental study in the Basic Aerodynamics Research Tunnel at the NASA Langley Research Center has provided new insight into the unsteady flow interaction around cylinders in tandem arrangement. Phase 1 of the study characterized the mean and unsteady near-field flow around two cylinders of equal diameter using 2-D Particle Image Velocimetry (PIV) and hot-wire anemometry. These measurements were performed at a Reynolds number of 1.66 x 10(exp 5), based on cylinder diameter, and spacing-to-diameter ratios, L/D, of 1.435 and 3.7. The current phase, Phase 2, augments this dataset by characterizing the surface flow on the same configurations using steady and unsteady pressure measurements and surface flow visualization. Transition strips were applied to the front cylinder during both phases to produce a turbulent boundary layer upstream of the flow separation. For these flow conditions and L/D ratios, surface pressures on both the front and rear cylinders show the effects of L/D on flow symmetry, pressure recovery, and the location of flow separation and attachment. Mean streamlines and instantaneous vorticity obtained from the PIV data are used to explain the flow structure in the gap and near-wake regions and its relationship to the unsteady surface pressures. The combination of off-body and surface measurements provides a comprehensive dataset to develop and validate computational techniques for predicting the unsteady flow field at higher Reynolds numbers.

  7. Measurements of the Flowfield Interaction Between Tandem Cylinders

    NASA Technical Reports Server (NTRS)

    Neuhart, Dan H.; Jenkins, Luther N.; Choudhari, Meelan M.; Khorrami, Mehdi R.

    2009-01-01

    This paper presents the most recent measurements from an ongoing investigation of the unsteady wake interference between a pair of circular cylinders in tandem. The purpose of this investigation is to help build an in-depth experimental database for this canonical flow configuration that embodies the effects of component interaction in landing gear noise. This new set of measurements augments the previous database at the primary Reynolds number (based on tunnel speed and cylinder diameter) of 1.66 105 in four important respects. First, better circumferential resolution of surface pressure fluctuations is obtained via cylinder "clocking". Second, higher resolution particle image velocimetry measurements of the shear layer separating from the cylinders are achieved. Third, the effects of simultaneous boundary layer trips along both the front and rear cylinders, versus front cylinder alone in the previous measurements, are studied. Lastly, on-surface and off-surface characteristics of unsteady flow near the "critical" cylinder spacing, wherein the flow switches intermittently between two states that are characteristic of lower and higher spacings, are examined. This critical spacing occurs in the middle of a relatively sudden change in the drag of either cylinder and is characterized by a loud intermittent noise and a flow behavior that randomly transitions between shear layer attachment to the rear cylinder and constant shedding and rollup in front of it. Analysis of this bistable flow state reveals much larger spanwise correlation lengths of surface pressure fluctuations than those at larger and smaller values of the cylinder spacing.

  8. Reuse of denaturing polyacrylamide gels for short tandem repeat analysis.

    PubMed

    Tereba, A; Micka, K A; Schumm, J W

    1998-11-01

    Denaturing polyacrylamide gel electrophoretic analysis of amplified polymorphic short tandem repeat (STR) loci using fluorescent markers is a mainstay of forensic and paternity testing. To reduce the drawback of preparing gels or using expensive precast gels, we have developed a simple and rapid method to reuse gels between 2 and 8 times over a period of several days. Following the initial electrophoresis and scan, the original samples are removed from the gel by a 1-1.5-h reverse-electrophoresis step. This step heats the gel for the next set of samples and can be performed several days after the initial electrophoresis. Sample bands remain sharp on subsequent runs, but edge effects (frowning of the outside lanes) become progressively worse and ultimately limit gel reuse. Well distortions and separation of the gel from the plates become problems if the gel is used more than twice. However, degassing the gel solution and bonding the gel to both plates eliminate these problems. Precast gels also can be used multiple times. Using this technique, we have successfully analyzed samples amplified with a nine-locus multiplex system and characterized the separated products using a fluorescent scanner and software. PMID:9821592

  9. A tandem mirror hybrid plume plasma propulsion facility

    NASA Technical Reports Server (NTRS)

    Chang-Diaz, F. R.; Yang, T. F.; Krueger, W. A.; Peng, S.; Urbahn, J.; Yao, X.; Griffin, D.

    1988-01-01

    A concept in electrodeless plasma propulsion, which is also capable of delivering a variable Isp, is presented. The concept involves a three-stage system of plasma injection, heating, and subsequent ejection through a magnetic nozzle. The nozzle produces the hybrid plume by the coaxial injection of hypersonic neutral gas. The gas layer, thus formed, protects the material walls from the hot plasma and, through increased collisions, helps detach it from the diverging magnetic field. The physics of this concept is evaluated numerically through full spatial and temporal simulations; these explore the operating characteristics of such a device over a wide region of parameter space. An experimental facility to study the plasma dynamics in the hybrid plume was built. The device consists of a tandem mirror operating in an asymmetric mode. A later upgrade of this system will incorporate a cold plasma injector at one end of the machine. Initial experiments involve the full characterization of the operating envelope, as well as extensive measurements of plasma properties at the exhaust. The results of the numerical simulations are described.

  10. Immunological dominance of Trypanosoma cruzi tandem repeat proteins.

    PubMed

    Goto, Yasuyuki; Carter, Darrick; Reed, Steven G

    2008-09-01

    Proteins with tandem repeat (TR) domains have been found in various protozoan parasites, often acting as targets of B-cell responses. However, the extent of the repeats within Trypanosoma cruzi, the causative agent of Chagas' disease, has not been examined well. Here, we present a systematic survey of the TR genes found in T. cruzi, in comparison with other organisms. Although the characteristics of TR genes varied from organism to organism, the presence of genes having large TR domains was unique to the trypanosomatids examined, including T. cruzi. Sequence analyses of T. cruzi TR genes revealed their divergency; they do not share such characteristics as sequence similarity or biased cellular location predicted by the presence of a signal sequence or transmembrane domain(s). In contrast, T. cruzi TR proteins seemed to possess significant antigenicity. A number of previously characterized T. cruzi antigens were detected by this computational screening, and several of those antigens contained a large TR domain. Further analyses of the T. cruzi genome demonstrated that previously uncharacterized TR proteins in this organism may also be immunodominant. Taken together, T. cruzi is rich in large TR domain-containing proteins with immunological significance; it is worthwhile further analyzing such characteristics of TR proteins as the copy number and consensus sequence of the repeats to determine whether they might contribute to the biological variability of T. cruzi strains with regard to induced immunological responses, host susceptibility, disease outcomes, and pathogenicity. PMID:18625739

  11. Probabilistic consensus scoring improves tandem mass spectrometry peptide identification.

    PubMed

    Nahnsen, Sven; Bertsch, Andreas; Rahnenführer, Jörg; Nordheim, Alfred; Kohlbacher, Oliver

    2011-08-01

    Database search is a standard technique for identifying peptides from their tandem mass spectra. To increase the number of correctly identified peptides, we suggest a probabilistic framework that allows the combination of scores from different search engines into a joint consensus score. Central to the approach is a novel method to estimate scores for peptides not found by an individual search engine. This approach allows the estimation of p-values for each candidate peptide and their combination across all search engines. The consensus approach works better than any single search engine across all different instrument types considered in this study. Improvements vary strongly from platform to platform and from search engine to search engine. Compared to the industry standard MASCOT, our approach can identify up to 60% more peptides. The software for consensus predictions is implemented in C++ as part of OpenMS, a software framework for mass spectrometry. The source code is available in the current development version of OpenMS and can easily be used as a command line application or via a graphical pipeline designer TOPPAS. PMID:21644507

  12. Tandem ion mobility spectrometry coupled to laser excitation.

    PubMed

    Simon, Anne-Laure; Chirot, Fabien; Choi, Chang Min; Clavier, Christian; Barbaire, Marc; Maurelli, Jacques; Dagany, Xavier; MacAleese, Luke; Dugourd, Philippe

    2015-09-01

    This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collision is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source. PMID:26429458

  13. Vortex evolution behind tandem cylinders under forced vibration

    NASA Astrophysics Data System (ADS)

    Yang, Yingchen; Aydin, Tayfun; Ekmekci, Alis

    2012-11-01

    Flow past two circular cylinders in tandem arrangement has been studied experimentally employing the hydrogen bubble visualization technique. The two cylinders had the same diameter (D = 6.35 mm), and were subjected to forced in-phase vibration in the cross-flow direction. The Reynolds number based on the cylinder diameter was Re = 250. Both the vibration frequency (fe) and center-to-center pitch ratio (P / D) were varied in certain ranges, whereas the vibration amplitude (A) was fixed at A / D = 0.25. The flow visualization resulted diverse and highly-repetitive vortex patterns. They were classified into two typical modes: a low-frequency mode and a high-frequency mode. The difference between the two modes is on the number of vortices formed per vibration cycle. For the low-frequency mode, the number is four; for the high-frequency model, it is two. In both modes, the vortex formation is phase-locked to the cylinder motion. For a specified mode with a fixed vortex number per cycle, the way the vortices evolve in the wake can be somewhat different by changing the vibration frequency and pitch ratio. These affecting factors have been examined in this work, and the associated vortex patterns have been characterized and compared.

  14. Liquid chromatography tandem mass spectrometry in the clinical laboratory.

    PubMed

    Adaway, Joanne E; Keevil, Brian G; Owen, Laura J

    2015-01-01

    Clinical laboratory medicine has seen the introduction and evolution of liquid chromatography tandem mass spectrometry in routine clinical laboratories over the last 10-15 years. There still exists a wide diversity of assays from very esoteric and highly specialist manual assays to more simplified kit-based assays. The technology is not static as manufacturers are continually making improvements. Mass spectrometry is now commonly used in several areas of diagnostics including therapeutic drug monitoring, toxicology, endocrinology, paediatrics and microbiology. Some of the most high throughput analyses or common analytes include vitamin D, immunosuppressant monitoring, androgen measurement and newborn screening. It also offers flexibility for the measurement of analytes in a variety of different matrices which would prove difficult with immunoassays. Unlike immunoassays or high-pressure liquid chromatography assays using ultraviolet or fluorescence detection, mass spectrometry offers better specificity and reduced interferences if attention is paid to potential isobaric compounds. Furthermore, multiplexing, which enables multiple analytes to be measured with the same volume of serum is advantageous, and the requirement for large sample volumes is decreasing as instrument sensitivity increases. There are many emerging applications in the literature. Using mass spectrometry to identify novel isoforms or modified peptides is possible as is quantification of proteins and peptides, with or without protein digests. Future developments by the manufacturers may also include mechanisms to improve the throughput of samples and strategies to decrease the level of skill required by the operators. PMID:25313226

  15. Vacuum vessel for the tandem Mirror Fusion Test Facility

    SciTech Connect

    Gerich, J.W.

    1986-03-10

    In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10/sup -8/ torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m/sup 3/ internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system.

  16. The 2 MV tandem pelletron accelerator of the Louvre Museum

    NASA Astrophysics Data System (ADS)

    Amsel, G.; Menu, M.; Moulin, J.; Salomon, J.

    1990-01-01

    The IBA facility of the Louvre Museum, code AGLAE, is based on the 6SDH-2 2 MV tandem Pelletron accelerator of NEC. A number of details of this machine have been specially designed with NEC to match the specific needs required for museum studies, i.e.: p, d, 3He, 4He, 15N beams from a single rf source, purely electrostatic focusing, halo-free submillimeter beam impacts, high-energy as well as low-energy operation at relatively high currents for resonance depth profiling of light nuclei including 1H, the possibility to automatize the machine operation as far as possible, development towards 14C AMS, and a microbeam extension. Special features of this machine include electrostatic steerers at the injection and electrostatic dog-leg steerers at the high-energy side, double slits at both sides of the accelerator, triplets instead of doublets for beam symmetry, turbomolecular recirculation of the stripper gas at the terminal, a new design of the stripper system itself, and a double feedback system with two capacitive pickoff plates for optimum energy spread and stability. The reasons of these special features will be explained and the characteristics of the machine as observed until now will be presented.

  17. Rapid comparison of diacetylmorphine on banknotes by tandem mass spectrometry.

    PubMed

    Ebejer, Karl A; Brereton, Richard G; Carter, James F; Ollerton, Samantha L; Sleeman, Richard

    2005-01-01

    A procedure is described for the determination of the distribution of the contamination of banknotes with controlled drugs using tandem mass spectrometry. The method is illustrated using diacetylmorphine, which is the major active component of heroin. A series of banknotes is introduced into the mass spectrometer and the intensities of two product ions (m/z 328 and 268) derived from the precursor protonated molecule (m/z 370) are recorded. A banknote is considered contaminated if it shows a significant peak for both product ions, and if the ratio of intensities of these two peaks falls within accepted limits. The distribution of diacetylmorphine on sterling banknotes taken from general circulation within the UK can be modelled by an arcsin (square root) transformation of the data or by a log transformation of the data with a higher proportion of contamination. The two models were found to be in close agreement, predicting an upper limit (at 99.9% confidence) of contamination on banknotes from general circulation between 9 and 10%. The percentage contamination in a case study was calculated and compared to the background distribution using the two models proposed. This comparison revealed that the contamination present in the case study was inconsistent with that present on banknotes in general circulation. PMID:15988724

  18. A new concept of a vacuum insulation tandem accelerator.

    PubMed

    Sorokin, I; Taskaev, S

    2015-12-01

    A tandem accelerator with vacuum insulation has been proposed and developed in the Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1MV potential of the high voltage electrode, converted into protons in the gas stripping target inside the electrode, and then the protons are accelerated again by the same potential. The potential for high voltage and intermediate electrodes is supplied by the sectioned rectifier through a sectioned bushing insulator with a resistive divider. In this work, we propose a radical improvement of the accelerator concept. It is proposed to abandon the separate placement of the accelerator and the power supply and connect them through the bushing insulator. The source of high voltage is proposed to be located inside the accelerator insulator with high voltage and intermediate electrodes mounted on it. This will reduce the facility height from 7m to 3m and make it really compact and attractive for placing in a clinic. This will significantly increase the stability of the accelerator because the potential for intermediate electrodes can be fed directly from the relevant sections of the rectifier. PMID:26122976

  19. Microchip-based forensic short tandem repeat genotyping.

    PubMed

    Kim, Yong Tae; Heo, Hyun Young; Oh, Shin Hye; Lee, Seung Hwan; Kim, Do Hyun; Seo, Tae Seok

    2015-08-01

    Micro total analysis system (?TAS) or lab-on-a-chip (LOC) technology has advanced over decades, and the high performance for chemical and biological analysis has been well demonstrated with advantages of low sample consumption, rapid analysis time, high-throughput screening, and portability. In particular, ?TAS or LOC based genetic applications have been extensively explored, and the short tandem repeat (STR) typing on a chip has garnered attention in the forensic community due to its special use for human identification in the field of mass disaster and missing person investigation, paternity testing, and perpetrator identification. The STR typing process consists of sample collection, DNA extraction, DNA quantitation, STR loci amplification, capillary electrophoretic separation, and STR profiling. Recent progress of microtechnology shows its ability to substitute the conventional analytical tools, and furthermore demonstrates total integration of the whole STR processes on a single wafer for on-site STR typing. In this review article, we highlighted some representative results for fluorescence labeling techniques, microchip-based DNA purification, on-chip polymerase chain reaction (PCR), a capillary electrophoretic microdevice, and a fully integrated microdevice for STR typing. PMID:25963560

  20. Planetary In Situ Sample Analysis with Tandem Two-Step Laser Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Brinckerhoff, W. B.; Getty, S. A.; Cornish, T. J.; Ecelberger, S. A.; Li, X.; Merrill Floyd, M. A.; Arevalo, R.; Elsila, J.; Callahan, M. P.

    2012-12-01

    Future surface missions to comets and outer solar system satellites such as Europa, Enceladus, and Titan will benefit strongly from investigations that can detect a wide range of organics in complex sample mixtures and ices, as well as determine the structure of selected molecules, to provide insight into their origin and evolution. At the same time, such missions are likely to be among the most highly constrained in mass and power resources, particularly those flown within the tightly focused Discovery and New Frontiers programs. Techniques requiring minimal or no sample manipulation or preparation may be needed to reduce complexity. Pulsed laser-based mass spectrometry may satisfy such requirements, with total instrument masses potentially less than 5 kg, particularly where analysis of higher-molecular weight, nonvolatile species is a priority objective. Prototype flight-compatible mass spectrometers under active development in our lab are based on direct ultraviolet Nd:YAG laser desorption and ionization (LDI) of solid samples under high vacuum. Prompt ions from a single few ns-duration laser pulse are accelerated into a compact time-of-flight mass spectrometer (TOF-MS). Both inorganic species including elements and oxides such as M_xO_y (M = Mg, Al, Cl, Ca, Fe; x, y = 1-4) from the mineral matrix as well as organics with molecular weights up to several kDa are readily detected over a range of laser intensities. To improve our ability to distinguish among peaks and patterns in the often-complex LDI spectra obtained from natural samples, we have recently begun systematically testing several critical instrument enhancements. First, by moving the common voltage bias of the ion flight tube and detector to a common negative potential, we are able to switch between positive and negative ion detection modes with only electrostatic switching. Inter-comparison of cation and anion spectra can provide highly diagnostic information on both inorganic (e.g., Na+ and K+ vs. Cl-) and organic moieties. Second, by focusing a separate "post-ionization" laser pulse just above the sample surface, we can achieve two-step laser mass spectrometry, or L2MS, in the same highly-miniaturized TOF-MS. L2MS enables selective analysis of aromatic organics even in the presence of a complex mineral matrix. Finally, by introducing an ion optical gate in the flight path, we are able to take advantage of the broad focusing capabilities of the "curved field" reflectron at the core of the TOF-MS to achieve pseudo-tandem structural analysis of selected organics. The high-speed gate is used to admit only the molecular ion/s of interest into the reflectron. Diagnostic fragments of the ion/s obtained through metastable decay or active collision-induced dissociation (CID) remain in focus despite having widely variable velocities and masses. As such even molecular isomers with differing fragmentation pathways may be distinguished through a series of pseudo-tandem mass spectra that could be obtained in an automatic process during a mission. The "real-world" benefits of these enhancements are being fully characterized using a set of synthetic and natural standard samples as well as several planetary analogs and meteorites.

  1. Tandem Benzophenone Amino Pyridines, Potent and Selective Inhibitors of Human Leukotriene C4 Synthase.

    PubMed

    Kleinschmidt, Thea K; Haraldsson, Martin; Basavarajappa, Devaraj; Lundeberg, Erik; Thulasingam, Madhuranayaki; Ekoff, Maria; Fauland, Alexander; Lehmann, Christoph; Kahnt, Astrid S; Lindbom, Lennart; Haeggström, Jesper Z

    2015-10-01

    Cysteinyl leukotrienes (cys-LTs) are lipid mediators of inflammation. The enzyme catalyzing synthesis of cys-LTs, leukotriene C4 synthase (LTC4S), is considered an important drug target. Here we report the synthesis and characterization of three tandem benzophenone amino pyridines as inhibitors of LTC4S in vitro and in vivo. The inhibitors were characterized in vitro using recombinant human LTC4S, MonoMac 6 cells, and a panel of peripheral human immune cells. In vivo, the compounds were tested in the Zymosan A-induced peritonitis mouse model. The molecules, denoted TK04, TK04a, and TK05, were potent and selective inhibitors of LTC4S with IC50 values of 116, 124, and 95 nM, respectively. Molecular docking revealed binding in a hydrophobic crevice between two enzyme monomers and interaction with two catalytic residues, Arg104 and Arg31. The TK compounds potently inhibited cys-LT biosynthesis in immune cells. In coincubations of platelets and polymorphonuclear leukocytes, inhibition of LTC4S led to shunting of LTA4 toward anti-inflammatory lipoxin A4, which was significantly enhanced by simultaneous inhibition of LTA4H. Finally, we found that TK05 (6 mg?kg(-1)?body weight) reduces LTE4 levels in peritoneal lavage fluid by 88% and significantly decreases vascular permeability in vivo. Our findings indicate that the TK compounds are valuable experimental tools in eicosanoid research in vitro and in vivo. Their chemical structures may serve as leads for further inhibitor design. Novel drugs depleting cys-LT production could be beneficial for treatment of inflammatory diseases associated with overexpression of LTC4S. PMID:26283693

  2. Determination of triapine, a ribonucleotide reductase inhibitor, in human plasma by liquid chromatography tandem mass spectrometry.

    PubMed

    Feng, Ye; Kunos, Charles A; Xu, Yan

    2015-09-01

    Triapine is an inhibitor of ribonucleotide reductase (RNR). Studies have shown that triapine significantly decreases the activity of RNR and enhanced the radiation-mediated cytotoxicity in cervical and colon cancer. In this work, we have developed and validated a selective and sensitive LC-MS/MS method for the determination of triapine in human plasma. In this method, 2-[(3-fluoro-2-pyridinyl)methylene] hydrazinecarbothioamide (NSC 266749) was used as the internal standard (IS); plasma samples were prepared by deproteinization with acetonitrile; tripaine and the IS were separated on a Waters Xbridge Shield RP18 column (3.5 µm; 2.1 × 50 mm) using a mobile phase containing 25.0% methanol and 75.0% ammonium bicarbonate buffer (10.0 mM, pH 8.50; v/v); column eluate was monitored by positive turbo-ionspray tandem mass spectrometry; and quantitation of triapine was carried out in multiple-reaction-monitoring mode. The method developed had a linear calibration range of 0.250-50.0 ng/mL with correlation coefficient of 0.999 for triapine in human plasma. The IS-normalized recovery and the IS-normalized matrix factor of triapine were 101-104% and 0.89-1.05, respectively. The accuracy expressed as percentage error and precision expressed as coefficient of variation were ?±6 and ?8%, respectively. The validated LC-MS/MS method was applied to the measurement of triapine in patient samples from a phase I clinical trial. PMID:25677991

  3. High performance liquid chromatography tandem mass spectrometry assay for the determination of cobinamide in pig plasma.

    PubMed

    McCracken, Brent A; Brittain, Matthew K

    2015-12-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been widely utilized for the analysis of compounds in biological matrices due to its selectivity and sensitivity. This study describes the application of an LC-MS/MS-based approach toward the analysis of cobinamide in Yorkshire pig plasma. The selectivity, accuracy, precision, recovery, linearity, range, carryover, sensitivity, matrix effect, interference, stability, reproducibility, and ruggedness of the method were investigated in pig plasma. The accuracy and precision of the method was determined to be within 10% over three different days over a range of concentrations (25-10,000ng/mL) that spanned more than two orders of magnitude. The lower limit of quantitation (LLOQ) for dicyanocobinamide was determined to be 25ng/mL in pig plasma. Carryover was acceptable, as the area response of the carryover blanks were ?15% of the area response of the nearest LLOQ standard for the analyte, while it was nonexistent for the internal standard. Specificity was ensured using six different lots of pig plasma. While the matrix effects of dicyanocobinamide in plasma were enhanced, ginsenoside Rb1 experienced signal suppression under the described conditions. The absolute recovery results for both compounds were consistent, precise, and reproducibly lower than expected at ?60% for dicyanocobinamide and ?22% for ginsenoside Rb1, confirming that a matrix standard curve was required for accurate quantitation. Cobinamide was shown to be very stable in matrix at various storage conditions including room temperature, refrigerated, and frozen at time intervals of 20h, 4 days, and 60 days respectively. This method was demonstrated to be sensitive, reproducible, stable, and rugged, and it should be applicable to the analysis of cobinamide in other biological matrices and species. PMID:26540437

  4. Performance-improved thin-film a-Si:H/?c-Si:H tandem solar cells by two-dimensionally nanopatterning photoactive layer

    PubMed Central

    2014-01-01

    Tandem solar cells consisting of amorphous and microcrystalline silicon junctions with the top junction nanopatterned as a two-dimensional photonic crystal are studied. Broadband light trapping, detailed electron/hole transport, and photocurrent matching modulation are considered. It is found that the absorptances of both junctions can be significantly increased by properly engineering the duty cycles and pitches of the photonic crystal; however, the photocurrent enhancement is always unevenly distributed in the junctions, leading to a relatively high photocurrent mismatch. Further considering an optimized intermediate layer and device resistances, the optimally matched photocurrent approximately 12.74 mA/cm2 is achieved with a light-conversion efficiency predicted to be 12.67%, exhibiting an enhancement of over 27.72% compared to conventional planar configuration. PMID:24521244

  5. Performance-improved thin-film a-Si:H/?c-Si:H tandem solar cells by two-dimensionally nanopatterning photoactive layer.

    PubMed

    Zhang, Cheng; Li, Xiaofeng; Shang, Aixue; Zhan, Yaohui; Yang, Zhenhai; Wu, Shaolong

    2014-01-01

    Tandem solar cells consisting of amorphous and microcrystalline silicon junctions with the top junction nanopatterned as a two-dimensional photonic crystal are studied. Broadband light trapping, detailed electron/hole transport, and photocurrent matching modulation are considered. It is found that the absorptances of both junctions can be significantly increased by properly engineering the duty cycles and pitches of the photonic crystal; however, the photocurrent enhancement is always unevenly distributed in the junctions, leading to a relatively high photocurrent mismatch. Further considering an optimized intermediate layer and device resistances, the optimally matched photocurrent approximately 12.74 mA/cm2 is achieved with a light-conversion efficiency predicted to be 12.67%, exhibiting an enhancement of over 27.72% compared to conventional planar configuration. PMID:24521244

  6. 10.2% power conversion efficiency polymer tandem solar cells consisting of two identical sub-cells.

    PubMed

    You, Jingbi; Chen, Chun-Chao; Hong, Ziruo; Yoshimura, Ken; Ohya, Kenichiro; Xu, Run; Ye, Shenglin; Gao, Jing; Li, Gang; Yang, Yang

    2013-08-01

    Polymer tandem solar cells with 10.2% power conversion efficiency are demonstrated via stacking two PDTP-DFBT:PC?? BM bulk heterojunctions, connected by MoO?/PEDOT:PSS/ZnO as an interconnecting layer. The tandem solar cells increase the power conversion efficiency of the PDTP-DFBT:PC?? BM system from 8.1% to 10.2%, successfully demonstrating polymer tandem solar cells with identical sub-cells of double-digit efficiency. PMID:23716123

  7. Stenting for malignant ureteral obstruction: Tandem, metal or metal-mesh stents.

    PubMed

    Elsamra, Sammy E; Leavitt, David A; Motato, Hector A; Friedlander, Justin I; Siev, Michael; Keheila, Mohamed; Hoenig, David M; Smith, Arthur D; Okeke, Zeph

    2015-07-01

    Extrinsic malignant compression of the ureter is not uncommon, often refractory to decompression with conventional polymeric ureteral stents, and frequently associated with limited survival. Alternative options for decompression include tandem ureteral stents, metallic stents and metal-mesh stents, though the preferred method remains controversial. We reviewed and updated our outcomes with tandem ureteral stents for malignant ureteral obstruction, and carried out a PubMed search using the terms "malignant ureteral obstruction," "tandem ureteral stents," "ipsilateral ureteral stents," "metal ureteral stent," "resonance stent," "silhouette stent" and "metal mesh stent." A comprehensive review of the literature and summary of outcomes is provided. The majority of studies encountered were retrospective with small sample sizes. The evidence is most robust for metal stents, whereas only limited data exists for tandem or metal-mesh stents. Metal and metal-mesh stents are considerably more expensive than tandem stenting, but the potential for less frequent stent exchanges makes them possibly cost-effective over time. Urinary tract infections have been associated with all stent types. A wide range of failure rates has been published for all types of stents, limiting direct comparison. Metal and metal-mesh stents show a high incidence of stent colic, migration and encrustation, whereas tandem stents appear to produce symptoms equivalent to single stents. Comparison is difficult given the limited evidence and heterogeneity of patients with malignant ureteral obstruction. It is clear that prospective, randomized studies are necessary to effectively scrutinize conventional, tandem, metallic ureteral and metal-mesh stents for their use in malignant ureteral obstruction. PMID:25950837

  8. Revisiting hyper- and hypo-androgenism by tandem mass spectrometry.

    PubMed

    Fanelli, Flaminia; Gambineri, Alessandra; Mezzullo, Marco; Vicennati, Valentina; Pelusi, Carla; Pasquali, Renato; Pagotto, Uberto

    2013-06-01

    Modern endocrinology is living a critical age of transition as far as laboratory testing and biochemical diagnosis are concerned. Novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for steroid measurement in biological fluids have abundantly demonstrated their analytical superiority over immunometric platforms that until now have dominated the world of steroid hormones determination in clinical laboratories. One of the most useful applications of LC-MS/MS is in the hypogonadism and hyperandrogenism field: LC-MS/MS has proved particularly suitable for the detection of low levels of testosterone typical of women and children, and in general more reliable in accurately determining hypogonadal male levels. This technique also offers increased informative power by allowing multi-analytical profiles that give a more comprehensive picture of the overall hormonal asset. Several LC-MS/MS methods for testosterone have been published in the last decade, some of them included other androgen or more comprehensive steroid profiles. LC-MS/MS offers the concrete possibility of achieving a definitive standardization of testosterone measurements and the generation of widely accepted reference intervals, that will set the basis for a consensus on the diagnostic value of biochemical testing. The present review is aimed at summarizing technological advancements in androgen measurements in serum and saliva. We also provide a picture of the state of advancement of standardization of testosterone assays, of the redefinition of androgen reference intervals by novel assays and of studies using LC-MS/MS for the characterization and diagnosis of female hyperandrogenism and male hypogonadism. PMID:23619762

  9. Flow and noise predictions for the tandem cylinder aeroacoustic benchmarka)

    NASA Astrophysics Data System (ADS)

    Brès, Guillaume A.; Freed, David; Wessels, Michael; Noelting, Swen; Pérot, Franck

    2012-03-01

    Flow and noise predictions for the tandem cylinder benchmark are performed using lattice Boltzmann and Ffowcs Williams-Hawkings methods. The numerical results are compared to experimental measurements from the Basic Aerodynamic Research Tunnel and Quiet Flow Facility (QFF) at NASA Langley Research Center. The present study focuses on two configurations: the first configuration corresponds to the typical setup with uniform inflow and spanwise periodic boundary condition. To investigate installation effects, the second configuration matches the QFF setup and geometry, including the rectangular open jet nozzle, and the two vertical side plates mounted in the span to support the test models. For both simulations, the full span of 16 cylinder diameters is simulated, matching the experimental dimensions. Overall, good agreement is obtained with the experimental surface data, flow field, and radiated noise measurements. In particular, the presence of the side plates significantly reduces the excessive spanwise coherence observed with periodic boundary conditions and improves the predictions of the tonal peak amplitude in the far-field noise spectra. Inclusion of the contributions from the side plates in the calculation of the radiated noise shows an overall increase in the predicted spectra and directivity, leading to a better match with the experimental measurements. The measured increase is about 1 to 2 dB at the main shedding frequency and harmonics, and is likely caused by reflections on the spanwise side plates. The broadband levels are also slightly higher by about 2 to 3 dB, likely due to the shear layers from the nozzle exit impacting the side plates.

  10. On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

    NASA Astrophysics Data System (ADS)

    Minárik, Stanislav

    2015-08-01

    A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensity acts on ions in any stage. In general, non-relativistic dynamics is used for the description of the ion transport in tandem accelerator. Energies of accelerated ions are too low and relativistic effects cannot be commonly observed by standard experimental technique. Estimation of possible relativistic correction of ion trajectories is therefore only a matter of calculation. In this note, we briefly present such calculation. Our aim is to show how using the relativistic dynamics modifies the particles trajectory in tandem type accelerator and what parameters determine this modification.

  11. Efficient Monolithic Perovskite/Silicon Tandem Solar Cell with Cell Area >1 cm(2).

    PubMed

    Werner, Jérémie; Weng, Ching-Hsun; Walter, Arnaud; Fesquet, Luc; Seif, Johannes Peter; De Wolf, Stefaan; Niesen, Bjoern; Ballif, Christophe

    2016-01-01

    Monolithic perovskite/crystalline silicon tandem solar cells hold great promise for further performance improvement of well-established silicon photovoltaics; however, monolithic tandem integration is challenging, evidenced by the modest performances and small-area devices reported so far. Here we present first a low-temperature process for semitransparent perovskite solar cells, yielding efficiencies of up to 14.5%. Then, we implement this process to fabricate monolithic perovskite/silicon heterojunction tandem solar cells yielding efficiencies of up to 21.2 and 19.2% for cell areas of 0.17 and 1.22 cm(2), respectively. Both efficiencies are well above those of the involved subcells. These single-junction perovskite and tandem solar cells are hysteresis-free and demonstrate steady performance under maximum power point tracking for several minutes. Finally, we present the effects of varying the intermediate recombination layer and hole transport layer thicknesses on tandem cell photocurrent generation, experimentally and by transfer matrix simulations. PMID:26687850

  12. Bifacial Si Heterojunction-Perovskite Organic-Inorganic Tandem to Produce Highly Efficient Solar Cell

    E-print Network

    Reza Asadpour; Raghu V. K. Chavali; M. Ryyan Khan; Muhammad A. Alam

    2015-05-15

    As single junction thin-film technologies, both Si heterojunction (HIT) and Perovskite based solar cells promise high efficiencies at low cost. One expects that a tandem cell design with these cells connected in series will improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics, however, we find that a traditional series connected tandem design suffers from low Jsc due to band-gap mismatch and current matching constraints. It requires careful thickness optimization of Perovskite to achieve any noticeable efficiency gain. Specifically, a traditional tandem cell with state-of-the-art HIT (24%) and Perovskite (20%) sub-cells provides only a modest tandem efficiency of ~25%. Instead, we demonstrate that a bifacial HIT/Perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration, the same state-of the-art sub-cells achieve a normalized output of 33%, exceeding the bifacial HIT performance at practical albedo reflections. Unlike the traditional design, this bifacial design is relatively insensitive to Perovskite thickness variations, which may translate to simpler manufacture and higher yield.

  13. Tandem solar cells deposited using hot-wire chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    van Veen, M. K.

    2003-05-01

    In this thesis, the application of the hot-wire chemical vapor deposition (HWCVD) technique for the deposition of silicon thin films is described. The HWCVD technique is based on the dissociation of silicon-containing gasses at the catalytic surface of a hot filament. Advantages of this technique are the high deposition rate, the low equipment costs, and the scalability. The main goal of this thesis is the optimization of the material properties of both hydrogenated amorphous silicon and microcrystalline silicon, so that these materials can be incorporated as the absorbing layers in tandem solar cells. Firstly, the influence of specific deposition parameters on the material quality of hydrogenated amorphous silicon was investigated. With the use of tantalum filaments, the deposition temperature could be decreased to moderate temperatures, while the (electronic) properties of the amorphous silicon were improved. However, at these low filament temperatures the silicide formation at the filaments was enhanced, resulting in a decrease in the deposition rate and a deterioration of the material quality over time. For extensive silicide formation, even epitaxial growth on crystalline wafers was observed. By preheating the filaments at elevated temperature before deposition, the influence of silicide formation could be minimized, which resulted in an improvement in the reproducibility of the material quality. Solar cells, in which the absorbing layer was made at moderate temperature, had high open-circuit voltages and high fill factors. The best n-i-p structured cell on plain stainless steel had an initial efficiency of 7.2 %. The incorporation of amorphous silicon in p-i-n structured cells with a textured front contact resulted in a higher short-circuit current density and a higher efficiency. Occasionally, many n-i-p structured cells showed shunting problems. The number of working cells was directly correlated to the age of the filaments. The presence of silicides on the wires resulted in a deterioration of the material quality and in the formation of shunting paths. By annealing the filaments before deposition, most silicon was evaporated from the filaments, and its influence was minimized. Furthermore, the incorporation of a buffer layer between the n- and i-layer resulted in a change of the sticking probability of adverse radicals and a reduced formation of shunting paths. Next, the influence of the hydrogen dilution of the silane gas on the material properties of microcrystalline silicon was investigated. Crystalline growth occurred at high hydrogen dilutions. Different microcrystalline layers were incorporated as the absorbing layer in n-i-p structured solar cells. The best cells were made with material that was deposited at the edge of the transition from the microcrystalline to the amorphous regime. The best cell had an initial efficiency of 4.8 %. Furthermore, the applicability of the HWCVD technique for the deposition of microcrystalline n-doped layers was investigated. The material with the highest conductivity was deposited at moderate temperature, using a high hydrogen dilution. Application of these n-layers in n-i-p structured solar cells resulted in similar open- circuit voltages, but lower short-circuit current densities compared to solar cells with a plasma-enhanced deposited n-layer. Further optimization of the hot-wire n-layers is necessary. Finally, the different intrinsic layers were incorporated in tandem solar cells. It was possible to obtain high open-circuit voltages and high fill factors. Spectral response measurements of n-i-p/n-i-p structured solar cells indicated that a low photocurrent easily leaked through the bottom cell, which did not occur in p-i-n/p-i-n cells. Apparently, the order in which the p- and n-layer in the tunnel-recombination junction were deposited influenced this small leakage effect. This junction needs further optimization in n-i-p structured tandem solar cells. Based on the achieved efficiencies for amorphous and microcrystalline solar cells on untextured stainless steel, effic

  14. Alkane metathesis by tandem alkane-dehydrogenation-olefin-metathesis catalysis and related chemistry.

    PubMed

    Haibach, Michael C; Kundu, Sabuj; Brookhart, Maurice; Goldman, Alan S

    2012-06-19

    Methods for the conversion of both renewable and non-petroleum fossil carbon sources to transportation fuels that are both efficient and economically viable could greatly enhance global security and prosperity. Currently, the major route to convert natural gas and coal to liquids is Fischer-Tropsch catalysis, which is potentially applicable to any source of synthesis gas including biomass and nonconventional fossil carbon sources. The major desired products of Fischer-Tropsch catalysis are n-alkanes that contain 9-19 carbons; they comprise a clean-burning and high combustion quality diesel, jet, and marine fuel. However, Fischer-Tropsch catalysis also results in significant yields of the much less valuable C(3) to C(8)n-alkanes; these are also present in large quantities in oil and gas reserves (natural gas liquids) and can be produced from the direct reduction of carbohydrates. Therefore, methods that could disproportionate medium-weight (C(3)-C(8)) n-alkanes into heavy and light n-alkanes offer great potential value as global demand for fuel increases and petroleum reserves decrease. This Account describes systems that we have developed for alkane metathesis based on the tandem operation of catalysts for alkane dehydrogenation and olefin metathesis. As dehydrogenation catalysts, we used pincer-ligated iridium complexes, and we initially investigated Schrock-type Mo or W alkylidene complexes as olefin metathesis catalysts. The interoperability of the catalysts typically represents a major challenge in tandem catalysis. In our systems, the rate of alkane dehydrogenation generally limits the overall reaction rate, whereas the lifetime of the alkylidene complexes at the relatively high temperatures required to obtain practical dehydrogenation rates (ca. 125 -200 °C) limits the total turnover numbers. Accordingly, we have focused on the development and use of more active dehydrogenation catalysts and more stable olefin-metathesis catalysts. We have used thermally stable solid metal oxides as the olefin-metathesis catalysts. Both the pincer complexes and the alkylidene complexes have been supported on alumina via adsorption through basic para-substituents. This process does not significantly affect catalyst activity, and in some cases it increases both the catalyst lifetime and the compatibility of the co-catalysts. These molecular catalysts are the first systems that effect alkane metathesis with molecular-weight selectivity, particularly for the conversion of C(n)n-alkanes to C(2n-2)n-alkanes plus ethane. This molecular-weight selectivity offers a critical advantage over the few previously reported alkane metathesis systems. We have studied the factors that determine molecular-weight selectivity in depth, including the isomerization of the olefinic intermediates and the regioselectivity of the pincer-iridium catalyst for dehydrogenation at the terminal position of the n-alkane. Our continuing work centers on the development of co-catalysts with improved interoperability, particularly olefin-metathesis catalysts that are more robust at high temperature and dehydrogenation catalysts that are more active at low temperature. We are also designing dehydrogenation catalysts based on metals other than iridium. Our ongoing mechanistic studies are focused on the apparently complex combination of factors that determine molecular-weight selectivity. PMID:22584036

  15. Tandem concentrator photovoltaic array applied to Space Station Freedom evolutionary power requirements

    NASA Technical Reports Server (NTRS)

    Fisher, Edward M., Jr.

    1991-01-01

    Additional power is required to support Space Station Freedom (SSF) evolution. Boeing Defense and Space Group, LeRC, and Entech Corporation have participated in the development of efficiency gallium arsenide and gallium antimonide solar cells make up the solar array tandem cell stacks. Entech's Mini-Dome Fresnel Lens Concentrators focus solar energy onto the active area of the solar cells at 50 times one solar energy flux. Development testing for a flight array, to be launched in Nov. 1992 is under way with support from LeRC. The tandem cells, interconnect wiring, concentrator lenses, and structure were integrated into arrays subjected to environmental testing. A tandem concentrator array can provide high mass and area specific power and can provide equal power with significantly less array area and weight than the baseline array design. Alternatively, for SSF growth, an array of twice the baseline power can be designed which still has a smaller drag area than the baseline.

  16. Tandem white organic light-emitting diodes adopting a C60:rubrene charge generation layer

    NASA Astrophysics Data System (ADS)

    Bi, Wen-Tao; Wu, Xiao-Ming; Hua, Yu-Lin; Sun, Jin-E.; Xiao, Zhi-Hui; Wang, Li; Yin, Shou-Gen

    2014-01-01

    Organic bulk heterojunction fullerence (C60) doped 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) as the high quality charge generation layer (CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes (OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of (0.40, 0.35) at 100 cd/m2 and (0.36, 0.34) at 1000 cd/m2 have been demonstrated by employing the developed CGL, respectively.

  17. Two-terminal monolithic InP-based tandem solar cells with tunneling intercell ohmic connections

    NASA Technical Reports Server (NTRS)

    Shen, C. C.; Chang, P. T.; Emery, K. A.

    1991-01-01

    A monolithic two-terminal InP/InGaAsP tandem solar cell was successfully fabricated. This tandem solar cell consists of a p/n InP homojunction top subcell and a 0.95 eV p/n InGaAsP homojunction bottom subcell. A patterned 0.95 eV n(+)/p(+) InGaAsP tunnel diode was employed as an intercell ohmic connection. The solar cell structure was prepared by two-step liquid phase epitaxial growth. Under one sun, AM1.5 global illumination, the best tandem cell delivered a conversion efficiency of 14.8 pct.

  18. Rapidly convergent algorithms for 3-D tandem and stellarator equilibria in the paraxial approximation

    SciTech Connect

    McNamara, B.

    1984-04-01

    Tandem and stellarator equilibria at high ..beta.. have proved hard to compute and the relaxation methods of Bauer et al., Chodura and Schluter, Hirshman, Strauss, and Pearlstein et al. have been slow to converge. This paper reports an extension of the low-..beta.. analytic method of Pearlstein, Kaiser, and Newcomb to arbitrary ..beta.. for tandem mirrors which converges in 10 to 20 iterations. Extensions of the method to stellarator equilibria are proposed and are very close to the analytic method of Johnson and Greene - the stellarator expansion. Most of the results of all these calculations can be adequately described by low-..beta.. approximations since the MHD stability limits occur at low ..beta... The tandem mirror, having weak curvature and a long central cell, allows finite Larmor radius effects to eliminate most ballooning modes and offers the possibility of really high average ..beta... This is the interest in developing such three-dimensional numerical algorithms.

  19. Perovskite Solar Cells with Large-Area CVD-Graphene for Tandem Solar Cells.

    PubMed

    Lang, Felix; Gluba, Marc A; Albrecht, Steve; Rappich, Jörg; Korte, Lars; Rech, Bernd; Nickel, Norbert H

    2015-07-16

    Perovskite solar cells with transparent contacts may be used to compensate for thermalization losses of silicon solar cells in tandem devices. This offers a way to outreach stagnating efficiencies. However, perovskite top cells in tandem structures require contact layers with high electrical conductivity and optimal transparency. We address this challenge by implementing large-area graphene grown by chemical vapor deposition as a highly transparent electrode in perovskite solar cells, leading to identical charge collection efficiencies. Electrical performance of solar cells with a graphene-based contact reached those of solar cells with standard gold contacts. The optical transmission by far exceeds that of reference devices and amounts to 64.3% below the perovskite band gap. Finally, we demonstrate a four-terminal tandem device combining a high band gap graphene-contacted perovskite top solar cell (Eg = 1.6 eV) with an amorphous/crystalline silicon bottom solar cell (Eg = 1.12 eV). PMID:26266857

  20. Enhancing practice Quality Enhancement Themes

    E-print Network

    Paxton, Anthony T.

    Enhancing practice Quality Enhancement Themes: The First Year Experience Transforming assessment DDaavviidd NNiiccooll #12;Preface The approach to quality and standards in higher education (HE) in Scotland the enhancement-led approach to quality and standards in Scottish higher education. Norman Sharp Director, QAA

  1. Gold-catalyzed tandem reactions of methylenecyclopropanes and vinylidenecyclopropanes.

    PubMed

    Zhang, Di-Han; Tang, Xiang-Ying; Shi, Min

    2014-03-18

    Gold catalysis is often the key step in the synthesis of natural products, and is a powerful tool for tandem or domino reaction processes. Both gold salts and complexes are among the most powerful soft Lewis acids for electrophilic activation of carbon-carbon multiple bonds toward a variety of nucleophiles. The core of these reactions relies on the interaction between gold catalysts and ?-bonds of alkenes, alkynes, and allenes. Activation of functional groups by gold complexes provides a useful and important method for facilitating many different organic transformations with high atom efficiency. Although they are highly strained, methylenecyclopropanes (MCPs) and vinylidenecyclopropanes (VDCPs) are readily accessible molecules that have served as useful building blocks in organic synthesis. Because of their unique structural and electronic properties, significant developments have been made in the presence of transition metal catalysts such as nickel, rhodium, palladium, and ruthenium during the past decades. However, less attention has been paid to the gold-catalyzed chemistry of MCPs and VDCPs. In this Account, we describe gold-catalyzed chemical transformations of MCPs and VDCPs developed both in our laboratory and by other researchers. Chemists have demonstrated that MCPs and VDCPs have amphiphilic properties. When MCPs or VDCPs are activated by a gold catalyst, subsequent nucleophilic attack by other reagents or ring-opening (ring-expansion) of the cyclopropane moiety will occur. However, the C-C double bonds of MCPs and VDCPs can also serve as nucleophilic reagents while more electrophilic reagents are present and activated by gold catalyst, and then further cascade reactions take place as triggered by the release of ring strain of cyclopropane. Based on this strategy, both our group and others have found some interesting gold-catalyzed transformations in recent years. These transformations of MCPs and VDCPs can produce a variety of polycyclic and heterocyclic structures, containing different sized skeletons. Moreover, we have carried out some isotopic labeling experiments and computational studies for mechanistic investigation. These reactions always give the desired products with high level control of chemo-, regio-, and diastereoselectivities, making them highly valuable for the synthesis of natural products and to the pharmaceutical industry and medicine in general. PMID:24168021

  2. Mouse-Specific Tandem IgY7-SuperMix Immunoaffinity Separations for Improved LC-MS/MS Coverage of the Plasma Proteome

    SciTech Connect

    Zhou, Jianying; Petritis, Brianne O.; Petritis, Konstantinos; Norbeck, Angela D.; Weitz, Karl K.; Moore, Ronald J.; Camp, David G.; Kulkarni, Rohit N.; Smith, Richard D.; Qian, Weijun

    2009-09-01

    We report on a customized mouse specific SuperMix immunoaffinity column and strategy for separating low abundance proteins from high and moderate abundance proteins in mouse plasma. When applied in tandem with a mouse IgY7 column that removes the seven most abundant proteins in blood, the SuperMix column captures >100 additional moderate abundance proteins, thus allowing significant enrichment of low abundance proteins in the flow-through fraction. A side-by-side comparison of results obtained from 2D-LC-MS/MS analyses of flow-through samples from IgY7 and SuperMix columns revealed a nearly two-fold improvement in the overall proteome coverage. Detection of low abundance proteins was also enhanced, as evidenced by a more than two-fold increase in the coverage of cytokines, growth factors, and other low abundance proteins. Moreover, the tandem separations are automated, reproducible, and allow effective identification of protein abundance differences from LC-MS/MS analyses. Considering the overall reproducibility and increased sensitivity using the IgY7-SuperMix separation system, we anticipate broad applications of this strategy for biomarker discovery using mouse models.

  3. J Physiol 587.20 (2009) pp 47694783 4769 The response of the tandem pore potassium channel

    E-print Network

    Feng, Jianfeng

    2009-01-01

    J Physiol 587.20 (2009) pp 4769­4783 4769 The response of the tandem pore potassium channel TASK-3 potassium channel TASK-3 is thought to open and shut at its selectivity filter in response to changes Tandem pore potassium channels help set the resting membrane potential of a wide variety of cells

  4. GENETIC DIVERSITY OF TYPHA LATIFOLIA (TYPHACEAE) AND THE IMPACT OF POLLUTANTS EXAMINED WITH TANDEM-REPETITIVE DNA PROBES

    EPA Science Inventory

    Genetic diversity at variable-number-tandem-repeat (VNTR) loci was examined in the common cattail, Typha latifolia (Typhaceae), using three synthetic DNA probes composed of tandemly repeated "core" sequences (GACA, GATA, and GCAC). The principal objectives of this investigation w...

  5. Copper-mediated tandem reaction of ?-ketoesters/ketones with tertiary amines for the synthesis of 2,3-dihydrofurans.

    PubMed

    Guo, Shengmei; Lu, Lin; Gong, Jiuhan; Zhu, Zheng; Xu, Feng; Wei, Zhenhong; Cai, Hu

    2015-04-21

    A copper-mediated tandem reaction of ?-ketoesters/ketones with tertiary amines was achieved, which provides a simple and efficient approach to the synthesis of 2,3-dihydrofuran derivatives. In this tandem reaction, the tertiary amine not only offers the methylene moiety but also serves as the base. PMID:25785570

  6. Renal function after tandem high-dose chemotherapy and autologous stem cell transplantation in children with Wilms tumor.

    PubMed

    Lee, Soo Hyun; Paik, Kyung Hoon; Sung, Ki Woong; Son, Meong Hi; Yoo, Keon Hee; Koo, Hong Hoe; Kim, Ju Youn; Cho, Eun Joo

    2011-12-01

    Despite increasing evidence that tandem HDCT and autoSCT might improve the survival of patients with high-risk solid tumors, patients with Wilms tumor may be at high risk of acute and chronic renal impairment during and after tandem HDCT/autoSCT because they usually have a single kidney. We investigated the feasibility of tandem HDCT/autoSCT in patients with Wilms tumor, focusing on renal function. Six patients with relapsed/progressed Wilms tumor were assigned to undergo tandem HDCT/autoSCT. One patient developed transient ARF during the first HDCT/autoSCT. All other patients underwent the second HDCT/autoSCT as scheduled. Acute renal dysfunction during the second HDCT/autoSCT was transient and manageable. Indicators of glomerular function such as creatinine clearance, serum creatinine, and albumin excretion were in the normal range at three?yr after tandem HDCT/autoSCT. Subclinical tubular dysfunctions, such as increased excretion of ?-N-acetylglucosaminidase and ?2-microglobulin, were identified at one and three yr after tandem HDCT/autoSCT; however, no patient required treatment for these conditions. These results are helpful to consider tandem HDCT/autoSCT as a treatment option in patients with Wilms tumor. Longer duration of follow-up and close monitoring of tubular function are required if tandem HDCT/autoSCT is indicated in patients with Wilms tumor. PMID:22060039

  7. Electrolytes based on TEMPO-Co tandem redox systems outperform single redox systems in dye-sensitized solar cells.

    PubMed

    Cong, Jiayan; Hao, Yan; Boschloo, Gerrit; Kloo, Lars

    2015-01-01

    A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)3 (2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (VOC ) increase, from 862?mV to 965?mV, was observed in the tandem redox system, while the short-circuit current density (JSC ) was maintained. The conversion efficiency was observed to increase from 7.1?% for cells containing the single Co(bpy)3 (2+/3+) redox couple, to 8.4?% for cells containing the TEMPO-Co tandem redox system. The reason for the increase in VOC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most efficient tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs. PMID:25504818

  8. 76 FR 40935 - Vertical Tandem Lifts in Marine Terminals; Extension of the Office of Management and Budget's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... Reduction Act of 1995 (44 U.S.C. 3506 et seq.) and Secretary of Labor's Order No. 5-2010 (72 FR 55355... Occupational Safety and Health Administration Vertical Tandem Lifts in Marine Terminals; Extension of the... collection requirements contained in the Standard on Vertical Tandem Lifts (VTLs) in Marine Terminals (29...

  9. 76 FR 40935 - Vertical Tandem Lifts in Marine Terminals; Extension of the Office of Management and Budget's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ...OSHA-2011-0066] Vertical Tandem Lifts in Marine Terminals; Extension of the Office of Management...Vertical Tandem Lifts (VTLs) in Marine Terminals (29 CFR part 1917). The collection...transporting vertically coupled containers in a terminal. DATES: Comments must be...

  10. Enhancement of Chaperone-Mediated Protein Folding Through Substrate Protein Interactions with the Groel C-Termini 

    E-print Network

    Weaver, Jeremy Scott

    2015-04-28

    of the C-terminal residues of the GroEL protein enhancing of the folding of substrate proteins. The 23 C-terminal residues of the GroEL monomer partially consist of four tandem repeats of a Gly-Gly-Met motif, leading to an intrinsically disordered...

  11. Nonlinear optical propagation in a tandem structure comprising nonlinear absorption and scattering materials

    SciTech Connect

    Wang, Kangpeng; Ju, Yongfeng; He, Jin; Zhang, Long E-mail: lzhang@siom.ac.cn; Wang, Jun E-mail: lzhang@siom.ac.cn; Chen, Yu; Blau, Werner J.

    2014-01-13

    Laser propagation in a tandem structure comprising carbon nanotubes and phthalocyanines is studied by Z-scan method. Due to the different mechanisms of the two materials, the laser beam can be attenuated with different absorptivities, by changing the sequence of light passing through each material. Numerical simulations considering the effect of path length and the change of nonlinear coefficient within each material are conducted for understanding the distribution of laser intensity in the tandem system and hence, fitting of the asymmetric Z-scan curves. The results are helpful for the design of nonlinear optical devices comprising multiple nonlinear materials and mechanisms.

  12. Desymmetrization of 7-azabicycloalkenes by tandem olefin metathesis for the preparation of natural product scaffolds

    PubMed Central

    Maison, Wolfgang; Büchert, Marina; Deppermann, Nina

    2007-01-01

    Background Tandem olefin metathesis sequences are known to be versatile for the generation of natural product scaffolds and have also been used for ring opening of strained carbo- and heterocycles. In this paper we demonstrate the potential of these reactions for the desymmetrization of 7-azabicycloalkenes. Results We have established efficient protocols for the desymmetrization of different 7-azabicycloalkenes by intra- and intermolecular tandem metathesis sequences with ruthenium based catalysts. Conclusion Desymmetrization of 7-azabicycloalkenes by olefin metathesis is an efficient process for the preparation of common natural product scaffolds such as pyrrolidines, indolizidines and isoindoles. PMID:18088413

  13. Synthesis of Highly Substituted Quinolines via a Tandem Ynamide Benzannulation/Iodocyclization Strategy.

    PubMed

    Willumstad, Thomas P; Boudreau, Paul D; Danheiser, Rick L

    2015-12-01

    A two-stage "tandem strategy" for the regiocontrolled synthesis of very highly substituted quinolines is described. Benzannulation based on the reaction of cyclobutenones or diazo ketones with N-propargyl-substituted ynamides proceeds via a cascade of several pericyclic reactions to generate multiply substituted aniline derivatives. In the second stage of the tandem strategy, triflate derivatives of the phenolic benzannulation products undergo Larock cyclization upon exposure to iodine to form products that are further elaborated by methods such as palladium-catalyzed coupling to generate quinolines that can be substituted at every position of the bicyclic system. PMID:26259034

  14. Solution-processed high-performance colloidal quantum dot tandem photodetectors on flexible substrates

    SciTech Connect

    Jiang, Zhenyu; You, Guanjun; Wang, Li; Liu, Jie; Xu, Jian; Hu, Wenjia; Zhang, Yu

    2014-08-28

    We report a high-performance colloidal quantum dot (CQD)-based near-infrared tandem photodetector fabricated on flexible substrates via solution-processed method. The tandem photodetector on poly(ethylene terephthalate) substrates exhibited low dark current and high detectivities over ?8.8?×?10{sup 11} Jones at near infrared range at ?0.5?V bias and over ?10{sup 13} Jones near 0 bias. The critical bend radii of ?8?mm and ?3?mm have been demonstrated for tensile and compressive bending, respectively. The performance of photodetectors remains stable under mechanical stress, making PbSe CQD material a promise candidate for flexible infrared sensing applications.

  15. Plasma confinement experiments in the TMX tandem mirror. Paper IAEA-CN-38/F-1

    SciTech Connect

    Simonen, T.C.; Anderson, C.A.; Casper, T.A.

    1980-05-22

    Results from the new Tandem Mirror Experiment (TMX) are described. Tandem-mirror density and potential profiles are produced using end-plug neutral-beam injection and central-cell gas-fueling. TMX parameters are near those predicted theoretically. The end-plug electron temperature is higher than in the comparably sized single-mirror 2XIIB. Axial confinement of the finite-beta central-cell plasma is improved by the end plugs by as much as a factor of 9. In TMX, end-plug microinstability limits central-cell confinement in agreement with theory.

  16. Tandem Z-Selective Cross-Metathesis/Dihydroxylation: Synthesis of anti-1,2-Diols.

    PubMed

    Dornan, Peter K; Wickens, Zachary K; Grubbs, Robert H

    2015-06-01

    A stereoselective synthesis of anti-1,2-diols has been developed using a multitasking Ru catalyst in an assisted tandem catalysis protocol. A cyclometalated Ru complex catalyzes first a Z-selective cross-metathesis of two terminal olefins, followed by a stereospecific dihydroxylation. Both steps are catalyzed by Ru, as the Ru complex is converted to a dihydroxylation catalyst upon addition of NaIO4. A variety of olefins were transformed into valuable, highly functionalized, and stereodefined molecules. Mechanistic experiments were performed to probe the nature of the oxidation step and catalyst inhibition pathways. These experiments point the way to more broadly applicable tandem catalytic transformations. PMID:25914354

  17. Tandem repeats discovery service (TReaDS) applied to finding novel cis-acting factors in repeat expansion diseases

    PubMed Central

    2012-01-01

    Background Tandem repeats are multiple duplications of substrings in the DNA that occur contiguously, or at a short distance, and may involve some mutations (such as substitutions, insertions, and deletions). Tandem repeats have been extensively studied also for their association with the class of repeat expansion diseases (mostly affecting the nervous system). Comparative studies on the output of different tools for finding tandem repeats highlighted significant differences among the sets of detected tandem repeats, while many authors pointed up how critical it is the right choice of parameters. Results In this paper we present TReaDS - Tandem Repeats Discovery Service, a tandem repeat meta search engine. TReaDS forwards user requests to several state of the art tools for finding tandem repeats and merges their outcome into a single report, providing a global, synthetic, and comparative view of the results. In particular, TReaDS allows the user to (i) simultaneously run different algorithms on the same data set, (ii) choose for each algorithm a different setting of parameters, and (iii) obtain a report that can be downloaded for further, off-line, investigations. We used TReaDS to investigate sequences associated with repeat expansion diseases. Conclusions By using the tool TReaDS we discover that, for 27 repeat expansion diseases out of a currently known set of 29, long fuzzy tandem repeats are covering the expansion loci. Tests with control sets confirm the specificity of this association. This finding suggests that long fuzzy tandem repeats can be a new class of cis-acting elements involved in the mechanisms leading to the expansion instability. We strongly believe that biologists can be interested in a tool that, not only gives them the possibility of using multiple search algorithm at the same time, with the same effort exerted in using just one of the systems, but also simplifies the burden of comparing and merging the results, thus expanding our capabilities in detecting important phenomena related to tandem repeats. PMID:22536970

  18. Linguistic Affordances of Korean-English Tandem Learning: A Case Study of Korean-English On-Line Chat Pair Interaction

    ERIC Educational Resources Information Center

    Cheon, Heesok

    2012-01-01

    In an attempt to explore an environment for language learning that tandem learning via real-time chat affords to foreign language learners and how language learners respond to those affordances, this study examined learner interaction in online Korean-English Tandem Learning with focus on how tandem learners engaged in peer assistance and how they…

  19. Blastomyces Virulence Adhesin-1 Protein Binding to Glycosaminoglycans Is Enhanced by Protein Disulfide Isomerase

    PubMed Central

    Beaussart, Audrey; Brandhorst, Tristan

    2015-01-01

    ABSTRACT Blastomyces adhesin-1 (BAD-1) protein mediates the virulence of the yeast Blastomyces dermatitidis, in part by binding host lung tissue, the extracellular matrix, and cellular receptors via glycosaminoglycans (GAGs), such as heparan sulfate. The tandem repeats that make up over 90% of BAD-1 appear in their native state to be tightly folded into an inactive conformation, but recent work has shown that they become activated and adhesive upon reduction of a disulfide linkage. Here, atomic force microscopy (AFM) of a single BAD-1 molecule interacting with immobilized heparin revealed that binding is enhanced upon treatment with protein disulfide isomerase and dithiothreitol (PDI/DTT). PDI/DTT treatment of BAD-1 induced a plateau effect in atomic force signatures that was consistent with sequential rupture of tandem binding domains. Inhibition of PDI in murine macrophages blunted BAD-1 binding to heparin in vitro. Based on AFM, we found that a short Cardin-Weintraub sequence paired with a WxxWxxW sequence in the first, degenerate repeat at the N terminus of BAD-1 was sufficient to initiate heparin binding. Removal of half of the 41 BAD-1 tandem repeats led to weaker adhesion, illustrating their role in enhanced binding. Mass spectroscopy of the tandem repeat revealed that the PDI-induced interaction with heparin is characterized by ruptured disulfide bonds and that cysteine thiols remain reduced. Further binding studies showed direct involvement of thiols in heparin ligation. Thus, we propose that the N-terminal domain of BAD-1 governs the initial association with host GAGs and that proximity to GAG-associated host PDI catalyzes activation of additional binding motifs conserved within the tandem repeats, leading to enhanced avidity and availability of reduced thiols. PMID:26396244

  20. Oak Ridge 25URC Tandem Accelerator 1999 SNEAP Lab Report

    SciTech Connect

    Haynes, D.L.; Juras, R.C.; Meigs, M.J.

    1999-10-01

    A major milestone was reached in the end of October 1998, when an experimentally-useful {sup 17}F beam (t{sub 1/2}=64.5 s) of 3 x 10{sup 4} ions per second (ips) was delivered to experimenters at the astrophysics endstation. A beam of {approx}8 {micro}A of 44 MeV deuterons incident on a target of thin fibers of HfO{sub 2}, together with an aluminum vapor feed, produced a beam of Al{sup 17}F{sup +} ions which, after first-stage mass analysis and breakup/charge exchange in Cs vapor, yielded 4 x 10{sup 7} ips F{sup {minus}} off the RIB platform. The {sup 17}F produced for this first useful experiment had only slight contamination of {sup 17}O (<1%), but the breakup of the molecular AlF introduced a large energy spread and the large emittance of the beam probably resulted in some transmission loss through the tandem. A new negative surface ionization source was installed and was used for most of the 1119 hours of {sup 17}F production in FY 1999. This source has been used to deliver 2 x 10{sup 5} ips of {sup 17}F (with {approx}3 {micro}A incident deuterons) but it can be highly contaminated with more than ten {sup 17}O for every {sup 17}F. A pure {sup 17}F beam of this magnitude has been obtained by using post-stripping to produce fully stripped fluorine ions with greater efficiency being obtained for the higher accelerated beam energies. Ion source development continues both at the UNISOR facility and at two ion source test stands. The next priority for RIB development is the production of a {sup 56}Ni beam. Because of the long lifetime and the highly refractory nature of Ni, the beam will not be produced by conventional ISOL techniques, but rather in a multi-sample sputter source, in which a target can be bombarded with Oak Ridge Isochronous Cyclotron (ORIC) beam for a period comparable with its half-life, and then rotated to a position where the activity can be exposed to a sputter beam for production of a {sup 56}Ni negative-ion beam. This batch mode source is designed so that one production target can be exposed to ORIC beams while another is simultaneously being sputtered. The batch mode source has produced stable beam on the RIB injector platform. Other development activities are primarily focused on a uranium carbide/reticulated vitreous carbon fiber target for production of neutron-rich beams by fission and a liquid germanium target system for production of proton-rich isotopes of As, Ga, and Se.

  1. Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: selection of extraction solvent.

    PubMed

    Mol, Hans G J; van Dam, Ruud C J; Steijger, Odile M

    2003-10-10

    A method based on liquid chromatography (LC)-mass spectrometry (MS)/MS was developed for sensitive determination of a number of less gas chromatography (GC)-amenable organophosphorus pesticides (OPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion) in cabbage and grapes. For extraction, several solvents were evaluated with respect to the possibility of direct injection, matrix-induced suppression or enhancement of response, and extraction efficiency. Overall, ethyl acetate was the most favourable solvent for extraction, although a solvent switch was required. For some pesticide/matrix combinations, reconstitution of the residue after evaporation required special attention. Extracts were analysed on a C18 column with polar endcapping. The pesticides were ionised using atmospheric pressure chemical ionisation on a tandem mass spectrometer in multiple reaction monitoring mode. The final method is straightforward and involves extraction with ethyl acetate and a solvent switch to 0.1% acetic acid/water without further cleanup. The method was validated at the 0.01 and 0.5 mg/kg level, for both cabbage and grapes. Recoveries were between 80 and 101% with R.S.D. < 11% (n = 5). The limit of quantification was 0.01 mg/kg and limits of detection were between 0.001 and 0.004 mg/kg. PMID:14570325

  2. Detection and structural characterization of amino polyaromatic hydrocarbon-deoxynucleoside adducts using fast atom bombardment and tandem mass spectrometry.

    PubMed

    Annan, R S; Giese, R W; Vouros, P

    1990-11-15

    Fast atom bombardment (FAB) and tandem mass spectrometry (MS/MS) are shown to be useful methods for the detection and structural characterization of nanogram amounts of amino polyaromatic hydrocarbon-nucleoside DNA adducts. The positive ion spectra of four aromatic amine guanosine adducts were studied in detail. The FAB spectra of these adducts exhibit an [MH]+ ion and a more abundant aglycon fragment ion, [AH2]+, which results from the loss of the deoxyribose sugar. The sensitivity of the adducts to FAB was enhanced by preparing trimethylsilyl (TMS) ether derivatives. High-quality full-scan spectra could be obtained on less than 70 ng of the derivatized adducts without signal averaging. With a B/E-linked scan of the [MH]+ ion for the TMS2 species, these same adducts could be detected by examination of their metastable ion spectra at levels as low as 4-5 ng (S/N greater than 10). Collision-induced dissociation (CID) of the [MH]+ ion yields the aglycon fragment and an ion, S1, which results from cleavage through the sugar. The CID spectrum of the aglycon [AH2]+ ion is much more useful, providing structural information relating to the base, the polyaromatic hydrocarbon, and, possibly, the site of covalent attachment. Differentiation of isomeric aminophenanthrene-guanine adducts was demonstrated on the basis of the CID spectra of their respective [AH2]+ ions. The use of TMS derivatives also improves the sensitivity of these methods. PMID:2077944

  3. Proteomic analysis of human O {sup 6}-methylguanine-DNA methyltransferase by affinity chromatography and tandem mass spectrometry

    SciTech Connect

    Niture, Suryakant K.; Doneanu, Catalin E.; Velu, Chinavenmeni S.; Bailey, Nathan I.; Srivenugopal, Kalkunte S. . E-mail: Kalkunte.srivenugopal@ttuhsc.edu

    2005-12-02

    Recent evidence suggests that human O {sup 6}-methylguanine-DNA methyltransferase (MGMT), a DNA repair protein that protects the genome against mutagens and accords tumor resistance to many anticancer alkylating agents, may have other roles besides repair. Therefore, we isolated MGMT-interacting proteins from extracts of HT29 human colon cancer cells using affinity chromatography on MGMT-Sepharose. Specific proteins bound to this column were identified by electrospray ionization tandem mass spectrometry and/or Western blotting. These procedures identified >60 MGMT-interacting proteins with diverse functions including those involved in DNA replication and repair (MCM2, PCNA, ORC1, DNA polymerase {delta}, MSH-2, and DNA-dependent protein kinase), cell cycle progression (CDK1, cyclin B, CDK2, CDC7, CDC10, 14-3-3 protein, and p21{sup waf1/cip1}), RNA processing and translation (poly(A)-binding protein, nucleolin, heterogeneous nuclear ribonucleoproteins, A2/B1, and elongation factor-1{alpha}), several histones (H4, H3.4, and H2A.1), and topoisomerase I. The heat shock proteins, HSP-90{alpha} and {beta}, also bound strongly with MGMT. The DNA repair activity of MGMT was greatly enhanced in the presence of interacting proteins or histones. These data, for the first time, suggest that human MGMT is likely to have additional functions, possibly, in sensing and integrating the DNA damage/repair-related signals with replication, cell cycle progression, and genomic stability.

  4. METHODS FOR AROMATIC AND HETEROCYCLIC AMINE CARCINOGEN-DNA ADDUCT ANALYSIS BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

    PubMed Central

    Neale, Jason R.; Smith, Ned B.; Pierce, William M.; Hein, David W.

    2008-01-01

    Xenobiotic-DNA adducts are used as biomarkers to assess the genotoxic effects of carcinogens. Rats were dosed with 4-aminobiphenyl (4-ABP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). DNA was isolated from the colons of vehicle and carcinogen-treated rats and digested using different nucleases and alkaline phosphatase. Deoxyribonucleoside adducts were quantified by capillary liquid chromatography-tandem mass spectrometry (LC-MS/MS) using isotope dilution methods with deuterated internal standards. Major adducts were those bound to the C8 position of deoxyguanosine. 3?- and 5?-Exonucleases were the most efficient nucleases at isolating dG-C8-ABP adducts. However, bulky adducts such as dG-C8-MeIQx and dG-C8-PhIP were better isolated using nuclease P1 rather than a combination of micrococcal nuclease and spleen phosphodiesterase. The use of DNase I enhanced the detection of all three adducts. We describe LC-MS/MS methods for DNA adduct detection and support the testing of different nucleases that increase DNA digestion efficiency and make available more DNA adducts for detection. PMID:19122802

  5. Monolith immuno-affinity enrichment liquid chromatography tandem mass spectrometry for quantitative protein analysis of recombinant bovine somatotropin in serum.

    PubMed

    Smits, Nathalie G E; Blokland, Marco H; Wubs, Klaas L; Nessen, Merel A; van Ginkel, Leen A; Nielen, Michel W F

    2015-08-01

    The use of recombinant bovine somatotropin (rbST) to enhance milk production is approved in several countries, but it is prohibited in the European Union. According to EU legislation, it is necessary to confirm positive screening results prior to enforcement. Although adequate screening assays are available nowadays, development of liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory methods to detect low levels of rbST is still a challenge. Here, we present a novel approach using immuno-affinity enrichment on monolithic micro-columns in combination with state-of-the-art ultra-high pressure LC-MS/MS (UHPLC-MS/MS) detection. The developed approach enables detection and confirmation of rbST in serum at a decision limit (CC?) concentration of 0.8 ng mL(-1). Furthermore, the method is easy to handle, robust and reproducible. We successfully applied the confirmatory method to serum samples from rbST treated cows that were found suspect after immunoassay-based screening. The use of rbST could be confirmed over 1 week after treatment, and the developed method demonstrated the sensitivity needed for effective control. Graphical Abstract Graphical summary of the workflow, for serum preparation, enrichment with monolith microcolumns and LC-MS/MS measurement of rbST. PMID:26077745

  6. Icariin enhances the healing of rapid palatal expansion induced root resorption in rats.

    PubMed

    Wang, Feng; Liu, Zhifeng; Lin, Songshan; Lu, Huaixiu; Xu, Juan

    2012-08-15

    Icariin has been reported to enhance bone healing and treat osteoporosis. In this study, we examined the effect of Icariin on rapid palatal expansion induced root resorption in rats. Our hypothesis is that Icariin can enhance the healing of rapid palatal expansion induced root resorption. Forty-eight male Wistar rats were divided randomly and equally into three groups (n=16 rats each). The rats were untreated (negative control) or treated with rapid palatal expansion without (positive control) or with Icariin at 2.5 mg/kg day (Icariin-treated groups). An initial force of 50×g was applied to the areas between the right and left upper first molars of the rats for 21 days. Eight rats were randomly chosen from each group, and the root resorption index (RRI) was determined with scanning electron microscopy (SEM). Upper first molar-centered buccal- lingual tissue slices were generated from the upper first molars and peridentium of the remaining eight rats from each group. Specimen slices were analyzed with HE and tararate-resistant acid phosphatase staining, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) immunohistochemistry, and optical microscopy. Analyses of cell number, densitometry, and one-way analysis of variance were performed. The Icariin-treated groups displayed decreased RRI values, decreased osteoclast numbers and activity levels, and increased OPG/RANKL expression ratios. High-power SEM revealed reparative cementum in the Icariin-treated samples. Icariin regulates osteoclast differentiation via the OPG/RANKL ratio, evoking a reparative effect on rapid palatal expansion induced root resorption in rats. PMID:22818561

  7. Quasi-linear gradients for capillary liquid chromatography with mass and tandem mass

    E-print Network

    Colonius, Tim

    Quasi-linear gradients for capillary liquid chromatography with mass and tandem mass spectrometry Gradient elution, capillary liquid chromatography mass spectrometry was performed with linear, static phase, high performance liquid chromatography (LC/MS) to the electrospray source.8,9 Among

  8. STRUCTURAL CHARACTERIZATION OF REACTIVE DYES USING SECONDARY ION MASS SPECTROMETRY/TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    Reactive Blue 19 (RB 19), its reactive form (RB 19-VS) and its hydrolyzed form, (RB 19-OH) were examined using liquid secondary ion mass spectrometry/tandem mass spectrometry (LSIMS/MS/MS) in the negative-ion mode under low-energy collision conditions (240-300 eV). tructurally ch...

  9. Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry

    E-print Network

    Hammock, Bruce D.

    Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry EUN (LC-MS/MS) method for determining urinary creatinine was developed and used to evaluate 24 h urine of creatinine was 0.59 min. The linear range was 1-2000 ng/mL, with a detection limit in urine of 1 ng/mL. LC

  10. Biomimetic total synthesis of forbesione and desoxymorellin utilizing a tandem Claisen/DielsAlder/Claisen rearrangement

    E-print Network

    Theodorakis, Emmanuel

    Biomimetic total synthesis of forbesione and desoxymorellin utilizing a tandem Claisen synthesis of forbesione (1) and desoxymorellin (3) is presented. Central to the strategy is a biomimetic Claisen/Diels­Alder reaction.8 This biomimetic scenario has been recently explored by Nicolaou and Li

  11. "One-pot" access to dihydrofurans via tandem oxidative difunctionalization and ring contraction of aminopyrans.

    PubMed

    Mandha, Santhosh Reddy; Alla, Manjula; Nanubolu, Jagadeesh Babu

    2014-07-01

    An operationally simple and efficient protocol for the construction of dihydrofuran derivatives has been accomplished via a sequential addition of N-chlorosuccinimide and a base to 2-amino-4H-pyran derivatives in alcohol medium. The one-pot protocol proceeding via tandem oxidative difunctionalization and ring contraction provides an entirely new strategy for the construction of the dihydrofuran skeleton. PMID:24846686

  12. Perovskite-Hematite Tandem Cells for Efficient Overall Solar Driven Water Splitting.

    PubMed

    Gurudayal; Sabba, Dharani; Kumar, Mulmudi Hemant; Wong, Lydia Helena; Barber, James; Grätzel, Michael; Mathews, Nripan

    2015-06-10

    Photoelectrochemical water splitting half reactions on semiconducting photoelectrodes have received much attention but efficient overall water splitting driven by a single photoelectrode has remained elusive due to stringent electronic and thermodynamic property requirements. Utilizing a tandem configuration wherein the total photovoltage is generated by complementary optical absorption across different semiconducting electrodes is a possible pathway to unassisted overall light-induced water splitting. Because of the low photovoltages generated by conventional photovoltaic materials (e.g., Si, CIGS), such systems typically consist of triple junction design that increases the complexity due to optoelectrical trade-offs and are also not cost-effective. Here, we show that a single solution processed organic-inorganic halide perovskite (CH3NH3PbI3) solar cell in tandem with a Fe2O3 photoanode can achieve overall unassisted water splitting with a solar-to-hydrogen conversion efficiency of 2.4%. Systematic electro-optical studies were performed to investigate the performance of tandem device. It was found that the overall efficiency was limited by the hematite's photocurrent and onset potential. To understand these limitations, we have estimated the intrinsic solar to chemical conversion efficiency of the doped and undoped Fe2O3 photoanodes. The total photopotential generated by our tandem system (1.87 V) exceeds both the thermodynamic and kinetic requirements (1.6 V), resulting in overall water splitting without the assistance of an electrical bias. PMID:25942281

  13. Supplemental Material for DNA Fingerprint Analysis of Three Short Tandem Repeat

    E-print Network

    Love, John J.

    1 Supplemental Material for ­ DNA Fingerprint Analysis of Three Short Tandem Repeat STR Loci genetics and its significance in DNA fingerprint analysis (plus an example calculation of allelic frequency Lab report for PCR and STR analysis. page 2 B. EXPERIMENTAL PROCEDURES Step I: Isolation of DNA using

  14. Combined Dynamic Arrays for Storing and Searching Semi-Ordered Tandem Mass Spectrometry Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When performing bioinformatics analysis on tandem mass spectrometry data, there is a computational need to efficiently store and sort these semi-ordered data sets. To solve this problem, a new data structure based on dynamic arrays was designed and implemented in an algorithm that parses semi-order...

  15. Tandem isomerization-decarboxylation for converting alkenoic fatty acids into alkenes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report a facile Ru-catalyzed route to alkenes from alkenoic fatty acids via a readily accessible pre-catalyst [Ru(CO)2RCO2]n. The catalyst apparently functions in a tandem mode by dynamically isomerizing the positions of double bonds in an aliphatic chain and, subsequently, decarboxylating specif...

  16. Fuel properties of heptadecene isomers prepared via tandem isomerization-decarboxylation of oleic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heptadecene isomers were prepared via tandem isomerization-decarboxylation of oleic acid using catalytic triruthenium dodecacarbonyl [Ru3(CO)12]. Chromatographic and spectroscopic characterization of the isolated heptadecene mixture indicated that it consisted of 96% internal trans isomers and 4% ar...

  17. Bio-olefins via tandem isomerization-decarboxylation catalysis upon fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A facile Ru-catalyzed route to bio-alkenes from alkenoic fatty acids will be discussed. A readily accessible pre-catalyst [Ru(CO)2RCO2]n. apparently functions in a tandem mode by dynamically isomerizing the positions of double bonds in an aliphatic chain and, subsequently, decarboxylating specific i...

  18. Expression Analysis of ABC Transporters Reveals Differential Functions of Tandemly Duplicated Genes in

    E-print Network

    Baillie, David

    molecules across the plasma membrane or the intracellular membranes of organelles, such as the endoplasmicExpression Analysis of ABC Transporters Reveals Differential Functions of Tandemly Duplicated Genes, BC Canada V5Z 1L6 We have previously identified 60 predicted ABC transporter genes

  19. 47 CFR 36.124 - Tandem switching equipment-Category 2.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Tandem switching equipment-Category 2. 36.124 Section 36.124 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES JURISDICTIONAL SEPARATIONS PROCEDURES; STANDARD PROCEDURES FOR SEPARATING TELECOMMUNICATIONS PROPERTY COSTS, REVENUES, EXPENSES, TAXES AND...

  20. Indium-catalyzed, novel route to ?,?-disubstituted indanones via tandem Nakamura addition-hydroarylation-decarboxylation sequence.

    PubMed

    Rajesh, Nimmakuri; Prajapati, Dipak

    2015-02-25

    A novel method for the construction of ?,?-disubstituted indanones has been developed via tandem Nakamura addition-hydroarylation-decarboxylation process. Indium(III) triflate was demonstrated as a versatile multitasking catalyst, which catalyzes three different chemical transformations under one-pot conditions. PMID:25619532

  1. Analysis and validation of proteomic data generated by tandem mass spectrometry

    E-print Network

    Kihara, Daisuke

    ,and renders databases containing proteomic data essentially useless3. In this review we discuss critical. For large-scale proteomics studies database searching remains the most frequently used peptideAnalysis and validation of proteomic data generated by tandem mass spectrometry Alexey I

  2. Improving Tandem Mass Spectrum Identification Using Peptide Retention Time Prediction across

    E-print Network

    Noble, William Stafford

    used technology is shotgun proteomics using liquid chromatog- raphy (LC)-tandem mass spectrometry (MS, and thus the identity of the original proteins, can be obtained by database search algorithms such as SEQUEST.3 As with any high-throughput technology, shotgun proteomics experiments must manage the tradeoff

  3. A Comparison of Tandem Walk Performance Between Bed Rest Subjects and Astronauts

    NASA Technical Reports Server (NTRS)

    Miller, Chris; Peters, Brian; Kofman, Igor; Philips, Tiffany; Batson, Crystal; Cerisano, Jody; Fisher, Elizabeth; Mulavara, Ajitkumar; Feiveson, Alan; Reschke, Millard; Bloomberg, Jacob

    2015-01-01

    Astronauts experience a microgravity environment during spaceflight, which results in a central reinterpretation of both vestibular and body axial-loading information by the sensorimotor system. Subjects in bed rest studies lie at 6deg head-down in strict bed rest to simulate the fluid shift and gravity-unloading of the microgravity environment. However, bed rest subjects still sense gravity in the vestibular organs. Therefore, bed rest isolates the axial-unloading component, thus allowing for the direct study of its effects. The Tandem Walk is a standard sensorimotor test of dynamic postural stability. In a previous abstract, we compared performance on a Tandem Walk test between bed rest control subjects, and short- and long-duration astronauts both before and after flight/bed rest using a composite index of performance, called the Tandem Walk Parameter (TWP), that takes into account speed, accuracy, and balance control. This new study extends the previous data set to include bed rest subjects who performed exercise countermeasures. The purpose of this study was to compare performance during the Tandem Walk test between bed rest subjects (with and without exercise), short-duration (Space Shuttle) crewmembers, and long-duration International Space Station (ISS) crewmembers at various time points during their recovery from bed rest or spaceflight.

  4. Monte Carlo particle simulation and finite-element techniques for tandem mirror transport

    SciTech Connect

    Rognlien, T.D.; Cohen, B.I.; Matsuda, Y.; Stewart, J.J. Jr.

    1985-12-01

    A description is given of numerical methods used in the study of axial transport in tandem mirrors owing to Coulomb collisions and rf diffusion. The methods are Monte Carlo particle simulations and direct solution to the Fokker-Planck equations by finite-element expansion. 11 refs.

  5. IDENTIFICATION OF FLAVONE AGLYCONES AND GLYCOSIDES IN SOYBEAN PODS BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS) was used to identify flavone aglycones and glycosides in soybean pods. Tandem mass spectrometry (MS/MS and MS3) and photodiode array detection were also utilized in flavone characterizat...

  6. MEASUREMENT OF OXIDATIVE STRESS PARAMETERS USING LIQUID CHROMATOGRAPHY - TANDEM MASS SPECTROSCOPY (LC-MS/MS)

    EPA Science Inventory

    What is the study?
    An invited review article. Measurement of oxidative stress parameters using liquid chromatography-tandem mass spectroscopy (LC-MS/MS)
    Why was it done?
    Although oxidative stress is frequently cited as a cause of various adverse biological eff...

  7. Analysis of the performances of an axial flow tandem pump based on CFD computations

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Bai, Z. Y.; Zhang, M. D.; Wang, G. Y.

    2012-11-01

    Tandem pump, compared with multistage pump, goes without guide vanes between impellers. Significant reduction of the axial geometry scale, resulting from lack of guide vanes, makes great sense to high-speed propulsion. Direct interactions between front and rear impellers may lead to special flows, which are different from those in a multistage pump. There are few studies of these differences. In this article, CFD computations of flows in an axial flow tandem pump are conducted to predict the performances. FBM turbulence model, which is introduced to commercial software, is used for the simulations. Circulation coefficient is defined to help analyze energy characteristics. The results demonstrate that power of the tandem pump increases slowly as discharge is getting larger. The tandem pump has better adaptability under large discharge conditions. The head of the rear impeller is not sensitive to discharge's change, which results from that the front impeller weakens the influence of discharge's change on the rear impeller, so pump's energy characteristics may be improved.

  8. Heat-pipe liquid-pool-blanket concept for the Tandem Mirror Reactor

    SciTech Connect

    Hoffman, M.A.; Werner, R.W.; Johnson, G.L.

    1981-10-01

    The blanket concept for the tandem mirror reactor described in this paper was developed to produce the medium temperature heat (approx. 850 to 950 K) for the General Atomic sulfur-iodine thermochemical process for producing hydrogen. This medium temperature heat from the blanket constitutes about 81% of the total power output of the fusion reactor.

  9. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    SciTech Connect

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.

    1996-02-01

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  10. Making the Case for Objective Performance Metrics in Newborn Screening by Tandem Mass Spectrometry

    ERIC Educational Resources Information Center

    Rinaldo, Piero; Zafari, Saba; Tortorelli, Silvia; Matern, Dietrich

    2006-01-01

    The expansion of newborn screening programs to include multiplex testing by tandem mass spectrometry requires understanding and close monitoring of performance metrics. This is not done consistently because of lack of defined targets, and interlaboratory comparison is almost nonexistent. Between July 2004 and April 2006 (N = 176,185 cases), the…

  11. ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS BY ION TRAP TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    An ion-trap mass spectrometer with a wave board and tandem mass spectrometry software was used to analyze gas chromatographically separated polycyclic aromatic hydrocarbons (PAHs) by using collision-induced dissociation (CID). The nonresonant (multiple collision) mode was used to...

  12. Sensitive, Preclinical Detection of Prions in Brain by nanospray liquid chromatography/tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More sensitive detection of prions in brain is important because it would allow early detection of disease in young animals and assure a safer food supply. We quantitated the amount of proteinase K-resistant prion protein (PrP 27-30) by use of nano-scale liquid chromatography coupled to a tandem ma...

  13. Butelase-mediated synthesis of protein thioesters and its application for tandem chemoenzymatic ligation.

    PubMed

    Cao, Yuan; Nguyen, Giang K T; Tam, James P; Liu, Chuan-Fa

    2015-11-24

    Using a recently discovered peptide ligase, butelase 1, we developed a novel method to access protein thioesters in good yield. We successfully combined it with native chemical ligation and sortase-mediated ligation in tandem for protein C-terminal labeling and dual-terminal labeling to exploit the orthogonality of these three ligation methods. PMID:26462854

  14. CHARACTERIZATION OF DOXYLAMINE AND PYRILAMINE METABOLITES VIA THERMOSPRAY/MASS SPECTROMETRY AND TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    Analysis of doxylamine N-oxide and pyrilamine N-oxide as synthetic standards and biologically derived metabolites by thermospray mass spectrometry (TSP/MS) provided (M + H)+ ions for each metabolite. TSP/tandem mass spectrometry (TSP/MS/MS) of the (M + H)+ ions provided fragment ...

  15. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.

    EPA Science Inventory

    In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

  16. TRINS: a method for gene modification by randomized tandem repeat insertions

    E-print Network

    Tawfik, Dan S.

    , the protein modifi- cations that are readily available through gene manipulations can be describedTRINS: a method for gene modification by randomized tandem repeat insertions Yakov Kipnis1,2, Eynat fragments of the target gene via rolling-circle amplification, and the con- current incorporation

  17. The heterochronic maize mutant Corngrass1 results from overexpression of a tandem microRNA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We cloned Cg1 and found that it encodes two tandem miR156 genes that are over expressed in the meristem and lateral organs. Furthermore, a target of Cg1 is teosinte glume architecture11, a gene known to have played a role in the domestication of maize from teosinte. Cg1 mutant plants overexpressing ...

  18. Ion Cyclotron Resonant Heating slot antenna for the Tandem Mirror Experiment-Upgrade

    SciTech Connect

    Brooksby, C.A.; Calderson, M.O.; Cummins, W.F.; Ferguson, S.W.; Williamson, V.L.

    1985-11-14

    The Ion Cyclotron Resonant Heating (ICRH) slot antenna has been a part of the ion and electron plasma heating system in the central cell region of the Tandem Mirror Experiment-Upgrade (TMX-U). This paper presents the mechanical design and arrangement of the antenna, coax feed lines, feedthroughs, and matching network for the slot antenna.

  19. Development of a tandem repeat-based multilocus typing system distinguishing Babesia bovis geographic isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mini and microsatellite sequences have proven to be excellent tools for the differentiation of strains and populations in several protozoan parasites due to their high variability. In the present work we have searched the genome of the tick-transmitted bovine hemoprotozoon Babesia bovis for tandem r...

  20. Nuclear breeder reactor fuel element with axial tandem stacking and getter

    DOEpatents

    Gibby, Ronald L. (Richland, WA); Lawrence, Leo A. (Kennewick, WA); Woodley, Robert E. (Richland, WA); Wilson, Charles N. (Richland, WA); Weber, Edward T. (Kennewick, WA); Johnson, Carl E. (Elk Grove, IL)

    1981-01-01

    A breeder reactor fuel element having a tandem arrangement of fissile and fertile fuel with a getter for fission product cesium disposed between the fissile and fertile sections. The getter is effective at reactor operating temperatures to isolate the cesium generated by the fissile material from reacting with the fertile fuel section.

  1. Structural basis for functional cooperation between tandem helicase cassettes in Brr2-mediated

    E-print Network

    Munk, Axel

    Structural basis for functional cooperation between tandem helicase cassettes in Brr2-mediated, two ring-like helicase cassettes intimately interact and functionally cooperate and how retinitis, and U6 in the major spliceosome) or its plethora of non-snRNP factors bear a preformed active center

  2. Algorithms for Identifying Protein Cross-links via Tandem Mass Spectrometry

    E-print Network

    Church, George M.

    an alternative ap- proach to detecting protein-protein interactions and adding reliable inter-amino acid conAlgorithms for Identifying Protein Cross-links via Tandem Mass Spectrometry Ting Chen Jake Ja e y method that provides a rapid solution to the discovery of protein-protein interactions and protein

  3. Tandem modular protein-based hydrogels constructed using a novel two-component approach.

    PubMed

    Lv, Shanshan; Cao, Yi; Li, Hongbin

    2012-01-31

    Leucine zipper sequences have been widely used to engineer protein-based hydrogels for biomedical applications. Previously, we have used this method to engineer tandem modular protein-based hydrogels as a step toward developing extracellular matrix-mimetic hydrogels. However, the spontaneous self-association of leucine zipper sequences in solution has made it challenging to express and purify tandem modular proteins carrying leucine zipper under native conditions. To obviate this problem, here we report a novel two-component approach to engineer tandem modular protein-based hydrogels. This methodology makes use of two complementary leucine zipper sequences (CCE and CCK), which do not self-associate but self-assemble into heterodimeric coiled-coils at neutral pH, as functional groups to drive the self-assembly of protein hydrogels. The two protein components are bifunctional and trifunctional tandem modular proteins carrying the leucine zipper functional groups. We found that the two proteins carrying CCE or CCK can be expressed and purified under native conditions with high yield. Upon mixing, the aqueous solution of the two proteins readily forms a transparent hydrogel. The resultant hydrogel can undergo reversible sol-gel transitions as a function of temperature, and shows much improved erosion properties. This method provides a new approach to tune the topology and physical properties of the protein hydrogels via genetic engineering, and opens the possibility to systematically explore the use of large native extracellular proteins to engineer extracellular matrix-mimetic hydrogels. PMID:22085110

  4. Optical design of GaN/In(x)Ga(1-x)N/cSi tandem solar cells with triangular diffraction grating.

    PubMed

    Lin, Leo Jyun-Hong; Chiou, Yih-Peng

    2015-06-01

    Optical design in enhancing optical absorption of group-III-nitride- and multiple quantum well-based GaN/InxGa1-xN/cSi dual-junction tandem solar cells with triangular diffraction grating is simulated and optimized by using combined two-dimensional rigorous coupled wave analysis and transfer matrix methods. This paper thoroughly examines these phenomena of optical absorption affected by antireflection coatings, multiple thin-film layers and diffraction gratings with the integrated perspectives of semiconductor physics and electromagnetic theory for the first time. An improvement of 58% in absorption compared to the prototype SC is obtained which means more than 80% of incoming light (h? > EgSi) can be harvested in this thin-film (< 4 ?m in total) design. PMID:26072886

  5. Randomized Trial of Oral Misoprostol Treatment for Cervical Ripening Before Tandem Application in Cervix Cancer

    SciTech Connect

    Cepni, Kimia; Gul, Sule; Cepni, Ismail; Gueralp, Onur; Sal, Veysel; Mayadagli, Alpaslan

    2011-11-01

    Purpose: To investigate the efficacy of oral misoprostol administered to facilitate tandem application to the cervix as a part of brachytherapy in patients with cervical cancer. Methods and Materials: Eighty patients with cervical cancer who had been planned to undergo brachytherapy at Dr. Luetfi Kirdar Kartal Training and Research Hospital were evaluated in a double-blind, prospective, randomized trial. Patients were divided randomly into two groups of 40 patients. The first and second groups received 400 {mu}g of misoprostol orally and placebo, respectively, 3 h before tandem application. The two groups were compared in terms of age, diameter of tumor, parity, age at first intercourse, amount of bleeding and pain at first tandem application, length of endometrial cavity measured by hysterometer, and size of Hegar dilators used for cervical dilatation. Results: Of all cases, 63.6%, 16.3%, 10%, 6.3%, 2.5%, and 1.3% were Stage IIB, IIIB, IIIA, IVA, IIA and IIC, respectively. Mean ({+-}SD) age (range) was 49.3 {+-} 13.1 (25-83) years and 56.6 {+-} 13.2 (30-78) years in the study and control groups, respectively (p = 0.015). Age at first intercourse, diameter of tumor, parity, amount of bleeding at first tandem application, and length of endometrial cavity measured by hysterometer were not significantly different between the two groups. Pain score was significantly higher in the control group (p < 0.001). Application was significantly easier in the study group compared with controls (p < 0.001). Average size of initial Hegar dilators used for cervical dilatation was significantly higher in the study group compared with controls (p = 0.017). Conclusion: Administration of misoprostol 400 {mu}g orally for cervical ripening before tandem application facilitates the procedure, increases patient tolerability and comfort, and may decrease complication rates.

  6. Specific Tandem Repeats Are Sufficient for Paramutation-Induced Trans-Generational Silencing

    PubMed Central

    Bader, Rechien; Arteaga-Vazquez, Mario A.; Chandler, Vicki L.

    2013-01-01

    Paramutation is a well-studied epigenetic phenomenon in which trans communication between two different alleles leads to meiotically heritable transcriptional silencing of one of the alleles. Paramutation at the b1 locus involves RNA-mediated transcriptional silencing and requires specific tandem repeats that generate siRNAs. This study addressed three important questions: 1) are the tandem repeats sufficient for paramutation, 2) do they need to be in an allelic position to mediate paramutation, and 3) is there an association between the ability to mediate paramutation and repeat DNA methylation levels? Paramutation was achieved using multiple transgenes containing the b1 tandem repeats, including events with tandem repeats of only one half of the repeat unit (413 bp), demonstrating that these sequences are sufficient for paramutation and an allelic position is not required for the repeats to communicate. Furthermore, the transgenic tandem repeats increased the expression of a reporter gene in maize, demonstrating the repeats contain transcriptional regulatory sequences. Transgene-mediated paramutation required the mediator of paramutation1 gene, which is necessary for endogenous paramutation, suggesting endogenous and transgene-mediated paramutation both require an RNA-mediated transcriptional silencing pathway. While all tested repeat transgenes produced small interfering RNAs (siRNAs), not all transgenes induced paramutation suggesting that, as with endogenous alleles, siRNA production is not sufficient for paramutation. The repeat transgene-induced silencing was less efficiently transmitted than silencing induced by the repeats of endogenous b1 alleles, which is always 100% efficient. The variability in the strength of the repeat transgene-induced silencing enabled testing whether the extent of DNA methylation within the repeats correlated with differences in efficiency of paramutation. Transgene-induced paramutation does not require extensive DNA methylation within the transgene. However, increased DNA methylation within the endogenous b1 repeats after transgene-induced paramutation was associated with stronger silencing of the endogenous allele. PMID:24146624

  7. Structure of a Longitudinal Actin Dimer Assembled by Tandem W Domains: Implications for Actin Filament Nucleation

    SciTech Connect

    Rebowski, Grzegorz; Namgoong, Suk; Boczkowska, Malgorzata; Leavis, Paul C.; Navaza, Jorge; Dominguez, Roberto

    2013-11-20

    Actin filament nucleators initiate polymerization in cells in a regulated manner. A common architecture among these molecules consists of tandem WASP homology 2 domains (W domains) that recruit three to four actin subunits to form a polymerization nucleus. We describe a low-resolution crystal structure of an actin dimer assembled by tandem W domains, where the first W domain is cross-linked to Cys374 of the actin subunit bound to it, whereas the last W domain is followed by the C-terminal pointed end-capping helix of thymosin {beta}4. While the arrangement of actin subunits in the dimer resembles that of a long-pitch helix of the actin filament, important differences are observed. These differences result from steric hindrance of the W domain with intersubunit contacts in the actin filament. We also determined the structure of the first W domain of Vibrio parahaemolyticus VopL cross-linked to actin Cys374 and show it to be nearly identical with non-cross-linked W-Actin structures. This result validates the use of cross-linking as a tool for the study of actin nucleation complexes, whose natural tendency to polymerize interferes with most structural methods. Combined with a biochemical analysis of nucleation, the structures may explain why nucleators based on tandem W domains with short inter-W linkers have relatively weak activity, cannot stay bound to filaments after nucleation, and are unlikely to influence filament elongation. The findings may also explain why nucleation-promoting factors of the Arp2/3 complex, which are related to tandem-W-domain nucleators, are ejected from branch junctions after nucleation. We finally show that the simple addition of the C-terminal pointed end-capping helix of thymosin {beta}4 to tandem W domains can change their activity from actin filament nucleation to monomer sequestration.

  8. Multiple tandemly repeated binding sites for cellular nuclear factor 1 that surround the major immediate-early promoters of simian and human cytomegalovirus.

    PubMed Central

    Jeang, K T; Rawlins, D R; Rosenfeld, P J; Shero, J H; Kelly, T J; Hayward, G S

    1987-01-01

    We show that the large DNA genomes of human and simian cytomegaloviruses (HCMV and SCMV, respectively) each contain multiple binding sites for purified cellular nuclear factor 1 (NF1) protein. Examination of the major immediate-early (IE) gene region in the HindIII H fragment of SCMV (Colburn) by filter binding assays showed that it competed 45-fold better than the single adenovirus type 2 binding site for NF1 protein and that it contained at least two distinct binding loci. Direct DNase I footprinting analyses of the 5' upstream locus detected at least 20 adjacent NF1-binding sites located between positions -600 and -1300 relative to the IE94 mRNA start site. DNA sequence analysis of the region revealed a conserved consensus NF1 recognition element (T)TGG(C/A)N5GCCAA embedded within each of 23 highly diverged 30-base-pair tandem repeats, together with a second downstream cluster of five consensus NF1-binding sites between positions +470 and +570 in the large first intron. Two separate NF1-binding loci were also found in the equivalent IE68 gene of HCMV(Towne) DNA, but in this case the DNA sequence and competition filter binding experiments indicated a maximum of only four to five consensus binding sites encompassing the promoter-enhancer region. In transient expression assays, neither the isolated upstream IE94 tandem repeats nor a synthetic single-copy consensus NF1-binding site acted as transcriptional cis activators or enhancers when placed adjacent to the simian virus 40 minimal early region promoter. We conclude that the large and complex 5' upstream promoter-regulatory region for the SCMV IE94 gene comprises two distinct domains. The previously described four sets of 13- to 18-base-pair interspersed repeat elements between -55 and -580 provide most of the high basal transcriptional strength, whereas the arrangement of further upstream tandemly repeated NF1-binding sites may contribute significantly to the expanded biological host range for expression of SCMV IE94 compared with HCMV IE68. Images PMID:3033283

  9. Tandem C-H oxidation/cyclization/rearrangement and its application to asymmetric syntheses of (-)-brussonol and (-)-przewalskine E.

    PubMed

    Jiao, Zhi-Wei; Tu, Yong-Qiang; Zhang, Qing; Liu, Wen-Xing; Zhang, Shu-Yu; Wang, Shao-Hua; Zhang, Fu-Min; Jiang, Sen

    2015-01-01

    Natural products are a vital source of lead compounds in drug discovery. Development of efficient tandem reactions to build useful compounds and apply them to the synthesis of natural products is not only a significant challenge but also an important goal for chemists. Here we describe a tandem C-H oxidation/cyclization/rearrangement of isochroman-derived allylic silylethers, promoted by DDQ and InCl3. This method allows the efficient construction of tricyclic benzoxa[3.2.1]octanes with a wide substrate scope. We employ this tandem reaction to achieve the asymmetric total syntheses of (-)-brussonol and (-)-przewalskine E. PMID:26081438

  10. Tandem C–H oxidation/cyclization/rearrangement and its application to asymmetric syntheses of (?)-brussonol and (?)-przewalskine E

    PubMed Central

    Jiao, Zhi-Wei; Tu, Yong-Qiang; Zhang, Qing; Liu, Wen-Xing; Zhang, Shu-Yu; Wang, Shao-Hua; Zhang, Fu-Min; Jiang, Sen

    2015-01-01

    Natural products are a vital source of lead compounds in drug discovery. Development of efficient tandem reactions to build useful compounds and apply them to the synthesis of natural products is not only a significant challenge but also an important goal for chemists. Here we describe a tandem C–H oxidation/cyclization/rearrangement of isochroman-derived allylic silylethers, promoted by DDQ and InCl3. This method allows the efficient construction of tricyclic benzoxa[3.2.1]octanes with a wide substrate scope. We employ this tandem reaction to achieve the asymmetric total syntheses of (?)-brussonol and (?)-przewalskine E. PMID:26081438

  11. DeconMSn: A Software Tool for accurate parent ion monoisotopic mass determination for tandem mass spectra

    SciTech Connect

    Mayampurath, Anoop M.; Jaitly, Navdeep; Purvine, Samuel O.; Monroe, Matthew E.; Auberry, Kenneth J.; Adkins, Joshua N.; Smith, Richard D.

    2008-04-01

    We present a new software tool for tandem MS analyses that: • accurately calculates the monoisotopic mass and charge of high–resolution parent ions • accurately operates regardless of the mass selected for fragmentation • performs independent of instrument settings • enables optimal selection of search mass tolerance for high mass accuracy experiments • is open source and thus can be tailored to individual needs • incorporates a SVM-based charge detection algorithm for analyzing low resolution tandem MS spectra • creates multiple output data formats (.dta, .MGF) • handles .RAW files and .mzXML formats • compatible with SEQUEST, MASCOT, X!Tandem

  12. Development of tandem time-of-flight instrumentation for the examination of prompt photodissociation of peptides using 193-nm radiation 

    E-print Network

    Morgan, Joseph William

    2006-04-12

    )............................................. 40 21 Tandem mass spectra of laminin fragment 925-933 (CDPGYIGSR)..... 41 22 Tandem mass spectra of [D-Tyr27,36, D-Thr32] neuropeptide Y fragment 27-36 amide (YINLITRQRY-NH2)......................................... 43 23 Tandem mass... consisting of two 24 precision steel translation stages (UMR8.51, Newport Corp., Irvine, CA) allowing 51 mm of motion in both x and y directions [101]. The sample plate is positioned by operation of two linear motion feedthroughs (BLM-133-2, MDC Corp...

  13. Oak Ridge 25URC Tandem Accelerator 2008 SNEAP Lab Report

    SciTech Connect

    Meigs, Martha J; Juras, Raymond C

    2011-01-01

    During FY 2008, the 25URC operated for slightly over 3,000 research hours. The radioactive species {sup 80}Ge and {sup 17,18}F accounted for 763 of these hours. This included an experiment using {sup 17}F which was only possible due to an improvement of a factor of 50 in beam intensity over our previous facility record. Twenty stable beam species were provided this year. Operation for the experimental program was at terminal potentials from 2.02 to 23.8 MV. Approximately 200 hours of conditioning were done to return the machine to operation after tank openings. There were six tank openings during the year: three scheduled for general maintenance and three unscheduled. Two of the unscheduled openings were required to correct shorting rod issues and the other was to reestablish communication with one of the major dead sections. On July 28, an event happened that caused all accelerators at the Holifield Radioactive Ion Beam Facility (HRIBF) to suspend operation. At approximately 8 AM on that Monday, during operations with approximately 12 {micro}A of 50-MeV protons on a uranium carbide target, delivering neutron-rich {sup 81}Zn beam to the new Low-energy Radioactive Ion Beam Spectroscopy Station (LeRIBSS), a radiological control technician (RCT) reported higher than normal radiation levels just outside the shield door to the IRIS1 vault (the room in which RIBs are produced at HRIBF). The measured dose rate equivalent was 4 mrem/hr. The presence of radiological contamination on the floor just outside the shield door was subsequently noted, as was the possible presence of airborne radioactivity. These observations were reported to facility management. Accelerators were put in standby immediately and the building evacuated. The event was subsequently declared a laboratory operational emergency. Parts of the building were cleared for reentry to collect belongings on Monday afternoon. The entire building was cleared for reoccupation on Tuesday morning after a detailed radiological survey found no contamination outside the shielded vaults. No decontamination was required. No individual received any detectable radiological dose as a result of this event. The 25URC tandem accelerator was given permission to resume operation with stable beams in early September, but radioactive ion production is still not allowed. Subsequent analysis indicated a release that consisted entirely of noble gasses (Xe and Kr isotopes). We believe we have identified two unrelated failures, one associated with the HVAC system and the other with the roughing system exhaust which accounts for both the escape of noble gasses into the IRIS1 vault and their migration outside the vault. An investigation team report is expected by October 24. At that time, corrective actions will be determined and the path to future radioactive ion beam production will be known. The break from operations allowed a few upgrades to be implemented. The most notable was the installation and commissioning of a SNICS ion source purchased from National Electrostatics Corporation (NEC). The SNICS replaced the old Alton/Aarhus source that we have used for many years. An ANU style gas cathode holder was purchased also but has not yet been implemented. The first beams have been produced by the source and the biggest problem encountered was reducing the beam for very low current experiments. A new power supply for the injection magnet was installed during this period also. Radioactive ion beam (RIB) development at the High Power Target Laboratory (HPTL) has been delayed this year while installing the platforms, conduits and equipment for the second Injector for Radioactive Ion Species (IRIS2) which is co-located with the HPTL facility. Therefore, the majority of development activities have been performed at the two off-line ion source test facilities (ISTF1 and ISTF2) and the On-Line Test Facility (OLTF). Both test facilities have been developing systems which will eventually be used with IRIS2. Two new tunable Ti:Sapphire lasers have been ordered for continuing development of an ion source

  14. ENHANCEMENT & ADVANCEMENT

    E-print Network

    Thompson, Michael

    , Savage, Martin, Borin, & Kustra, (2011). PEARLS Model: Institutional Influencers that Enhance and Advance University Teaching and Learning The PEARLS model, was developed to depict the Institutional Influencers all disciplines, and applicable to all institutions (Chick & Poole, 2014). PEARLS Model: Institutional

  15. Biocatalyst Enhancement

    EPA Science Inventory

    The increasing availability of enzyme collections has assisted attempts by pharmaceutical producers to adopt green chemistry approaches to manufacturing. A joint effort between an enzyme producer and a pharmaceutical manufacturer has been enhanced over the past three years by ena...

  16. Tandem repeat regions within the Burkholderia pseudomallei genome and their application for high resolution genotyping

    PubMed Central

    U'Ren, Jana M; Schupp, James M; Pearson, Talima; Hornstra, Heidie; Friedman, Christine L Clark; Smith, Kimothy L; Daugherty, Rebecca R Leadem; Rhoton, Shane D; Leadem, Ben; Georgia, Shalamar; Cardon, Michelle; Huynh, Lynn Y; DeShazer, David; Harvey, Steven P; Robison, Richard; Gal, Daniel; Mayo, Mark J; Wagner, David; Currie, Bart J; Keim, Paul

    2007-01-01

    Background The facultative, intracellular bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a serious infectious disease of humans and animals. We identified and categorized tandem repeat arrays and their distribution throughout the genome of B. pseudomallei strain K96243 in order to develop a genetic typing method for B. pseudomallei. We then screened 104 of the potentially polymorphic loci across a diverse panel of 31 isolates including B. pseudomallei, B. mallei and B. thailandensis in order to identify loci with varying degrees of polymorphism. A subset of these tandem repeat arrays were subsequently developed into a multiple-locus VNTR analysis to examine 66 B. pseudomallei and 21 B. mallei isolates from around the world, as well as 95 lineages from a serial transfer experiment encompassing ~18,000 generations. Results B. pseudomallei contains a preponderance of tandem repeat loci throughout its genome, many of which are duplicated elsewhere in the genome. The majority of these loci are composed of repeat motif lengths of 6 to 9 bp with 4 to 10 repeat units and are predominately located in intergenic regions of the genome. Across geographically diverse B. pseudomallei and B.mallei isolates, the 32 VNTR loci displayed between 7 and 28 alleles, with Nei's diversity values ranging from 0.47 and 0.94. Mutation rates for these loci are comparable (>10-5 per locus per generation) to that of the most diverse tandemly repeated regions found in other less diverse bacteria. Conclusion The frequency, location and duplicate nature of tandemly repeated regions within the B. pseudomallei genome indicate that these tandem repeat regions may play a role in generating and maintaining adaptive genomic variation. Multiple-locus VNTR analysis revealed extensive diversity within the global isolate set containing B. pseudomallei and B. mallei, and it detected genotypic differences within clonal lineages of both species that were identical using previous typing methods. Given the health threat to humans and livestock and the potential for B. pseudomallei to be released intentionally, MLVA could prove to be an important tool for fine-scale epidemiological or forensic tracking of this increasingly important environmental pathogen. PMID:17397553

  17. Cross-lingual Portability of MLP-Based Tandem Features -- A Case Study for English and Hungarian 

    E-print Network

    Toth, Laszlo; Frankel, Joe; Gosztolya, Gabor; King, Simon

    2008-01-01

    One promising approach for building ASR systems for less-resourced languages is cross-lingual adaptation. Tandem ASR is particularly well suited to such adaptation, as it includes two cascaded modelling steps: feature ...

  18. Transition-metal-free tandem radical thiocyanooxygenation of olefinic amides: a new route to SCN-containing heterocycles.

    PubMed

    Yang, Hua; Duan, Xin-Hua; Zhao, Jing-Feng; Guo, Li-Na

    2015-04-17

    A novel transition-metal-free tandem radical thiocyanooxygenation of olefinic amides with potassium thiocyanate has been developed under mild conditions. This method allows a reliable and practical access to diverse SCN-containing heterocycles bearing a wide range of functional groups in good to excellent yields. Furthermore, this tandem reaction provides a simple method for the construction of C-O and C-S bonds in one step. PMID:25839712

  19. Two-dimensional cascade test of a highly loaded, low-solidity, tandem airfoil turbine rotor blade

    NASA Technical Reports Server (NTRS)

    Kline, J. F.; Stabe, R. G.

    1973-01-01

    A tip region section of a low-solidity tandem airfoil blade for a turbine rotor was tested in a two-dimensional cascade tunnel at solidities of 0.736 and 0.912. Blade surface static pressures and blade exit total and static pressure and flow angle were surveyed. Blade surface velocities, wake shapes, and kinetic energy losses were analyzed and compared with values for 1.852 solidity tandem airfoil blading.

  20. Tandem photovoltaic solar cell with III-V diffused junction booster cell

    SciTech Connect

    Fraas, L.M.; Avery, J.E.; Girard, G.R.

    1992-02-25

    This patent describes a GaAs/GaSb tandem solar cell having improved conversion efficiency. It comprises: a GaAs upper cell having a predetermined bandgap selected for optimal performance of the tandem solar cell; a GaSb booster cell positioned beneath the GaAs upper cell to receive light transmitted through the GaAs upper cell and responsive to such light; and light conditioning means associated with the upper cell and the booster cell for achieving and energy conversion efficiency of at least 31% AMO. This patent also describes the cell as defined in claim 2, wherein the light conditioning means includes a prismatic coverglass for optically eliminating grid line obscuration losses on at least the upper cell and a concentrating lens for focusing solar energy onto an upper surface of the upper cell.

  1. Structure and Notch Receptor Binding of the Tandem WWE Domain of Deltex

    SciTech Connect

    Zweifel,M.; Leahy, D.; Barrick, D.

    2005-01-01

    Deltex is a cytosolic effector of Notch signaling thought to bind through its N-terminal domain to the Notch receptor. Here we report the structure of the Drosophila Deltex N-terminal domain, which contains two tandem WWE sequence repeats. The WWE repeats, which adopt a novel fold, are related by an approximate two-fold axis of rotation. Although the WWE repeats are structurally distinct, they interact extensively and form a deep cleft at their junction that appears well suited for ligand binding. The two repeats are thermodynamically coupled; this coupling is mediated in part by a conserved segment that is immediately C-terminal to the second WWE domain. We demonstrate that although the Deltex WWE tandem is monomeric in solution, it forms a heterodimer with the ankyrin domain of the Notch receptor. These results provide structural and functional insight into how Deltex modulates Notch signaling, and how WWE modules recognize targets for ubiquitination.

  2. Pyramidal surface textures for light trapping and antireflection in perovskite-on-silicon tandem solar cells.

    PubMed

    Schneider, Bennett W; Lal, Niraj N; Baker-Finch, Simeon; White, Thomas P

    2014-10-20

    Perovskite-on-silicon tandem solar cells show potential to reach > 30% conversion efficiency, but require careful optical control. We introduce here an effective light-management scheme based on the established pyramidal texturing of crystalline silicon cells. Calculations show that conformal deposition of a thin film perovskite solar cell directly onto the textured front surface of a high efficiency silicon cell can yield front surface reflection losses as low as 0.52mA/cm(2). Combining this with a wavelength-selective intermediate reflector between the cells additionally provides effective light-trapping in the high-bandgap top cell, resulting in calculated absolute efficiency gains of 2 - 4%. This approach provides a practical and effective method to adapt existing high efficiency silicon cell designs for use in tandem cells, with conversion efficiencies approaching 35%. PMID:25607299

  3. Protein-Protein Interactions of Tandem Affinity Purified Protein Kinases from Rice

    PubMed Central

    Rohila, Jai S.; Chen, Mei; Chen, Shuo; Chen, Johann; Cerny, Ronald L.; Dardick, Christopher; Canlas, Patrick; Fujii, Hiroaki; Gribskov, Michael; Kanrar, Siddhartha; Knoflicek, Lucas; Stevenson, Becky; Xie, Mingtang; Xu, Xia; Zheng, Xianwu; Zhu, Jian-Kang; Ronald, Pamela; Fromm, Michael E.

    2009-01-01

    Eighty-eight rice (Oryza sativa) cDNAs encoding rice leaf expressed protein kinases (PKs) were fused to a Tandem Affinity Purification tag (TAP-tag) and expressed in transgenic rice plants. The TAP-tagged PKs and interacting proteins were purified from the T1 progeny of the transgenic rice plants and identified by tandem mass spectrometry. Forty-five TAP-tagged PKs were recovered in this study and thirteen of these were found to interact with other rice proteins with a high probability score. In vivo phosphorylated sites were found for three of the PKs. A comparison of the TAP-tagged data from a combined analysis of 129 TAP-tagged rice protein kinases with a concurrent screen using yeast two hybrid methods identified an evolutionarily new rice protein that interacts with the well conserved cell division cycle 2 (CDC2) protein complex. PMID:19690613

  4. Hydrogen vibrational population distributions and negative ion generation in tandem high density hydrogen discharges

    SciTech Connect

    Hiskes, J.R.; Karo, A.M.; Willmann, P.A.

    1984-10-01

    The tandem high-density hydrogen negative-ion-source system is optimized to identify the largest possible ion concentrations and extracted ion currents. The optimization includes varying the length of the second chamber, varying neutral gas and electron densities, and varying the ratio of atomic to molecular density. Vibrational excitation occurs via high-energy electron excitation (E-V process) and H/sub 2//sup +/ surface neutralization (s-V process). These processes are considered separately and acting in parallel. The solutions are presented in terms of a dimensional scale factor, R. For a system scale length R = 1 cm, optimum extracted current densities are in the range 50 to 100 mA cm/sup -2/. A single-chamber s-V system with the high-energy electron component suppressed can provide larger ion concentrations than a tandem E-V, s-V system. 14 references, 4 figures.

  5. The Lawrence Livermore National Laboratory (LLNL) multi-user Tandem Laboratory

    SciTech Connect

    Davis, J.C.

    1988-09-01

    An FN tandem laboratory, cofounded by several Lawrence Livermore National Laboratory Divisions, Sandia Livermore, and the University of California Regents, is now operational at Livermore. The accelerator, formerly the University of Washington injector, has been upgraded with SF/sub 6/, Dowlish tubes, and a NEC pelletron charging system. A conventional duoplasmatron, a tritium source, and two Cs sputtering sources will be fielded on the accelerator. Pulsed beams will be available from two source positions. The laboratory has been designed to accommodate up to 19 experimental positions with excellent optics and working vacuum. The facility is unshielded with both accelerator and radiological systems under the control of a distributed microprocessor system. Research activities at the tandem include nuclear physics and astrophysics, materials science and characterization programs, and accelerator mass spectrometry for archaeology, biomedical, environmental and geoscience investigators. 3 refs., 1 fig.

  6. Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

    SciTech Connect

    St Clair, Jason M.; McCabe, David C.; Crounse, John D.; Steiner, Urs; Wennberg, Paul O.

    2010-09-15

    A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH{sub 3}OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH{sub 3}OOH with CF{sub 3}O{sup -} clustering chemistry. CH{sub 3}OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H{sub 2}O is {+-}80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H{sub 2}O is estimated to be better than {+-}40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

  7. Hyper sensitive protein detection by Tandem-HTRF reveals Cyclin D1 dynamics in adult mouse

    PubMed Central

    Zampieri, Alexandre; Champagne, Julien; Auzemery, Baptiste; Fuentes, Ivanna; Maurel, Benjamin; Bienvenu, Frédéric

    2015-01-01

    We present here a novel method for the semi-quantitative detection of low abundance proteins in solution that is both fast and simple. It is based on Homogenous Time Resolved Förster Resonance Energy Transfer (HTRF), between a lanthanide labeled donor antibody and a d2 or XL665 labeled acceptor antibody that are both raised against different epitopes of the same target. This novel approach we termed “Tandem-HTRF”, can specifically reveal rare polypeptides from only a few microliters of cellular lysate within one hour in a 384-well plate format. Using this sensitive approach, we observed surprisingly that the core cell cycle regulator Cyclin D1 is sustained in fully developed adult organs and harbors an unexpected expression pattern affected by environmental challenge. Thus our method, Tandem-HTRF offers a promising way to investigate subtle variations in the dynamics of sparse proteins from limited biological material. PMID:26503526

  8. Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

    SciTech Connect

    Hunt, A.L.; Lang, D.D.; Nexsen, W.E.; Pickles, W.L.; Turner, W.C.

    1984-09-01

    The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal barrier experiments designed to provide an improved performance for tandem mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering system. Various recorded pressure vs time histories produced by the machine's internal vacuum systems and their pumping mechanisms are presented. An upgraded computer code for calculating dynamic pressures is described. Our concluding remarks deal with the problems of establishing and maintaining a pressure measuring system for a large fusion experiment, where the quality and reliability of components must be carefully considered.

  9. Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure

    PubMed Central

    May, Matthias M.; Lewerenz, Hans-Joachim; Lackner, David; Dimroth, Frank; Hannappel, Thomas

    2015-01-01

    Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators. PMID:26369620

  10. Tandem Domains with Tuned Interactions Are a Powerful Biological Design Principle.

    PubMed

    Nussinov, Ruth; Tsai, Chung-Jung

    2015-11-01

    Allosteric effects of mutations, ligand binding, or post-translational modifications on protein function occur through changes to the protein's shape, or conformation. In a cell, there are many copies of the same protein, all experiencing these perturbations in a dynamic fashion and fluctuating through different conformations and activity states. According to the "conformational selection and population shift" theory, ligand binding selects a particular conformation. This perturbs the ensemble and induces a population shift. In a new PLOS Biology paper, Melacini and colleagues describe a novel model of protein regulation, the "Double-Conformational Selection Model", which demonstrates how two tandem ligand-binding domains interact to regulate protein function. Here we explain how tandem domains with tuned interactions-but not single domains-can provide a blueprint for sensitive activation sensors within a narrow window of ligand concentration, thereby promoting signaling control. PMID:26618518

  11. Tandem Mirror Experiment Upgrade (TMX-U) overview-recent events

    SciTech Connect

    Calderon, M.O.; Bell, H.H.

    1985-11-14

    Since its construction and commissioning was completed in the winter of 1981, the Tandem Mirror Experiment Upgrade (TMX-U) has been conducting tandem mirror thermal barrier experiments. The work, following the fall of 1983 when strong plugging with thermal barriers was achieved, has been directed toward controlling radial transport and forming thermal barriers with high density and Beta. This paper describes the overall engineering component of these efforts. Major changes to the machine have included vacuum improvements, changes to the Electron and Ion Cyclotron Resonance Heating systems (ECRH and ICRH), and the installation of a Plasma Potential Control system (PPC) for radial transport reduction. TMX-U operates an extensive diagnostics system that acquires data from 21 types of diagnostic instruments with more than 600 channels, in addition to 246 machine parameters. The changes and additions will be presented. The closing section of this paper will describe the initial study work for a proposed TMX-U octupole configured machine.

  12. Searching molecular structure databases with tandem mass spectra using CSI:FingerID

    PubMed Central

    Dührkop, Kai; Shen, Huibin; Meusel, Marvin; Rousu, Juho; Böcker, Sebastian

    2015-01-01

    Metabolites provide a direct functional signature of cellular state. Untargeted metabolomics experiments usually rely on tandem MS to identify the thousands of compounds in a biological sample. Today, the vast majority of metabolites remain unknown. We present a method for searching molecular structure databases using tandem MS data of small molecules. Our method computes a fragmentation tree that best explains the fragmentation spectrum of an unknown molecule. We use the fragmentation tree to predict the molecular structure fingerprint of the unknown compound using machine learning. This fingerprint is then used to search a molecular structure database such as PubChem. Our method is shown to improve on the competing methods for computational metabolite identification by a considerable margin. PMID:26392543

  13. Charge generation layers for solution processed tandem organic light emitting diodes with regular device architecture.

    PubMed

    Höfle, Stefan; Bernhard, Christoph; Bruns, Michael; Kübel, Christian; Scherer, Torsten; Lemmer, Uli; Colsmann, Alexander

    2015-04-22

    Tandem organic light emitting diodes (OLEDs) utilizing fluorescent polymers in both sub-OLEDs and a regular device architecture were fabricated from solution, and their structure and performance characterized. The charge carrier generation layer comprised a zinc oxide layer, modified by a polyethylenimine interface dipole, for electron injection and either MoO3, WO3, or VOx for hole injection into the adjacent sub-OLEDs. ToF-SIMS investigations and STEM-EDX mapping verified the distinct functional layers throughout the layer stack. At a given device current density, the current efficiencies of both sub-OLEDs add up to a maximum of 25 cd/A, indicating a properly working tandem OLED. PMID:25832776

  14. Individual identification of cats and dogs using mitochondrial DNA tandem repeats?

    PubMed

    Fridez, F; Rochat, S; Coquoz, R

    1999-01-01

    Cats and dogs are very common animals in the human environment. In Switzerland, one in five households owns a cat or a dog. Their hairs are very easily transferred and could be used as a frequent trace evidence. Using DNA analysis, identification of these animals should be possible as it is in human identification. However, most of the time, no nuclear DNA can be recovered from the hair. It is therefore necessary to rely on mtDNA. Cats and dogs have tandemly repeated sequences in their mtDNA control region. In this study, the authors show that these tandem repeats are very polymorphic but are also the source of a very high level of heteroplasmy. The authors, therefore, examined if this might prevent their use in forensic identification. PMID:10795405

  15. Tandem array of nanoelectronic readers embedded coplanar to a fluidic nanochannel for correlated single biopolymer analysis

    PubMed Central

    Lesser-Rojas, Leonardo; Sriram, K. K.; Liao, Kuo-Tang; Lai, Shui-Chin; Kuo, Pai-Chia; Chu, Ming-Lee; Chou, Chia-Fu

    2014-01-01

    We have developed a two-step electron-beam lithography process to fabricate a tandem array of three pairs of tip-like gold nanoelectronic detectors with electrode gap size as small as 9?nm, embedded in a coplanar fashion to 60?nm deep, 100?nm wide, and up to 150??m long nanochannels coupled to a world-micro-nanofluidic interface for easy sample introduction. Experimental tests with a sealed device using DNA-protein complexes demonstrate the coplanarity of the nanoelectrodes to the nanochannel surface. Further, this device could improve transverse current detection by correlated time-of-flight measurements of translocating samples, and serve as an autocalibrated velocimeter and nanoscale tandem Coulter counters for single molecule analysis of heterogeneous samples. PMID:24753731

  16. Searching molecular structure databases with tandem mass spectra using CSI:FingerID.

    PubMed

    Dührkop, Kai; Shen, Huibin; Meusel, Marvin; Rousu, Juho; Böcker, Sebastian

    2015-10-13

    Metabolites provide a direct functional signature of cellular state. Untargeted metabolomics experiments usually rely on tandem MS to identify the thousands of compounds in a biological sample. Today, the vast majority of metabolites remain unknown. We present a method for searching molecular structure databases using tandem MS data of small molecules. Our method computes a fragmentation tree that best explains the fragmentation spectrum of an unknown molecule. We use the fragmentation tree to predict the molecular structure fingerprint of the unknown compound using machine learning. This fingerprint is then used to search a molecular structure database such as PubChem. Our method is shown to improve on the competing methods for computational metabolite identification by a considerable margin. PMID:26392543

  17. A transposable element can drive the concerted evolution of tandemly repetitious DNA.

    PubMed Central

    Thompson-Stewart, D; Karpen, G H; Spradling, A C

    1994-01-01

    Recombination and conversion have been proposed to drive the concerted evolution of tandemly repeated DNA sequences. However, specific correction events within the repeated genes of multicellular organisms have not been observed directly, so their nature has remained speculative. We investigated whether the excision of transposable P elements from tandemly repeated sequences would induce unequal gene conversion. Genetically marked elements located in a subtelomeric repeat were mobilized, and the structure of the region was analyzed in progeny. We observed that the number of repeats was frequently altered. Decreases were more common than increases, and this bias probably resulted from intrinsic mechanisms governing P element-induced double-strand break repair. Our results suggest that transposable elements play an important role in the evolution of repetitious DNA. Images PMID:8090766

  18. Tandem Domains with Tuned Interactions Are a Powerful Biological Design Principle

    PubMed Central

    Nussinov, Ruth; Tsai, Chung-Jung

    2015-01-01

    Allosteric effects of mutations, ligand binding, or post-translational modifications on protein function occur through changes to the protein’s shape, or conformation. In a cell, there are many copies of the same protein, all experiencing these perturbations in a dynamic fashion and fluctuating through different conformations and activity states. According to the “conformational selection and population shift” theory, ligand binding selects a particular conformation. This perturbs the ensemble and induces a population shift. In a new PLOS Biology paper, Melacini and colleagues describe a novel model of protein regulation, the “Double-Conformational Selection Model”, which demonstrates how two tandem ligand-binding domains interact to regulate protein function. Here we explain how tandem domains with tuned interactions—but not single domains—can provide a blueprint for sensitive activation sensors within a narrow window of ligand concentration, thereby promoting signaling control. PMID:26618518

  19. Tandem injected relativistic heavy ion facility at Brookhaven: Present and future

    SciTech Connect

    Thieberger, P.; Barton, D.S.; Benjamin, J.; Chasman, C.; Foelsche, H.; Wegner, H.E.

    1987-04-01

    The Brookhaven Tandem Facility has been recently joined to the Alternating Gradient Synchrotron (AGS) by means of an approx. =680 meter long heavy ion transfer line. The design and construction of this line are described as well as the Tandem and AGS modifications which made it possible to initiate a relativistic heavy ion research program. Operational experience and performance during the first 14.6 GeV/amu /sup 16/O and /sup 28/Si runs are reviewed. At present the facility is capable of accelerating ions up to mass approx.32. Future developments are described which will lead to the acceleration of heavier ions up to gold, and hopefully to the construction of a relativistic heavy ion collider for the entire mass range at center of mass energies up to 250 GeV per nucleon pair.

  20. Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure.

    PubMed

    May, Matthias M; Lewerenz, Hans-Joachim; Lackner, David; Dimroth, Frank; Hannappel, Thomas

    2015-01-01

    Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators. PMID:26369620

  1. Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure

    NASA Astrophysics Data System (ADS)

    May, Matthias M.; Lewerenz, Hans-Joachim; Lackner, David; Dimroth, Frank; Hannappel, Thomas

    2015-09-01

    Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators.

  2. Flexible organic tandem solar modules: a story of up-scaling

    NASA Astrophysics Data System (ADS)

    Spyropoulos, George D.; Kubis, Peter; Li, Ning; Lucera, Luca; Salvador, Michael; Baran, Derya; Machui, Florian; Ameri, Tayebeh; Voigt, Monika M.; Brabec, Christoph J.

    2014-10-01

    The competition in the field of solar energy between Organic Photovoltaics (OPVs) and several Inorganic Photovoltaic technologies is continuously increasing to reach the ultimate purpose of energy supply from inexpensive and easily manufactured solar cell units. Solution-processed printing techniques on flexible substrates attach a tremendous opportunity to the OPVs for the accomplishment of low-cost and large area applications. Furthermore, tandem architectures came to boost up even more OPVs by increasing the photon-harvesting properties of the device. In this work, we demonstrate the road of realizing flexible organic tandem solar modules constructed by a fully roll-to-roll compatible processing. The modules exhibit an efficiency of 5.4% with geometrical fill factors beyond 80% and minimized interconnection-resistance losses. The processing involves low temperature (<70 °C), coating methods compatible with slot die coating and high speed and precision laser patterning.

  3. Complex formation of p65/RelA with nuclear Akt1 for enhanced transcriptional activation of NF-{kappa}B

    SciTech Connect

    Kwon, Osong; Kim, Kyung A; He, Long; Jung, Mira; Jeong, Sook Jung; Ahn, Jong Seog Kim, Bo Yeon

    2008-01-25

    Akt1 was revealed to interact with Ki-Ras in the cytoplasm of Ki-Ras-transformed human prostate epithelial cells, 267B1/K-ras. Moreover, p65/RelA in the nucleus was found to interact with both Ki-Ras and Akt1, suggesting the nuclear translocation of Akt1:Ki-Ras complex for NF- {kappa}B activation. In support of this, compared with wild type Akt1, the dominant negative Akt1 mutant was decreased in its nuclear expression, reducing the Ki-Ras-induced NF-{kappa}B transcriptional activation. Moreover, inhibitors of Ras (sulindac sulfide and farnesyltransferase inhibitor I) or PI3K/Akt (wortmannin), reduced the amounts of Akt1 and Ki-Ras in the nucleus as well as partial NF-{kappa}B activity. The complete inhibition of Ki-Ras-induced NF-{kappa}B activation, however, could only be obtained by combined treatment with wortmannin and proteasome inhibitor-1. Accordingly, clonogenic assay showed Akt1 contribution to I{kappa}B{alpha}-mediated NF-{kappa}B activation for oncogenic cell growth by Ki-Ras. Our data suggest a crucial role of Ki-Ras:Akt1 complex in NF-{kappa}B transcriptional activation and enhancement of cell survival.

  4. Perfluorooctanoic acid enhances colorectal cancer DLD-1 cells invasiveness through activating NF-?B mediated matrix metalloproteinase-2/-9 expression

    PubMed Central

    Miao, Chen; Ma, Jun; Zhang, Yajie; Chu, Yimin; Li, Ji; Kuai, Rong; Wang, Saiyu; Peng, Haixia

    2015-01-01

    Objective: Perfluorooctanoic acid (PFOA) is widely used in consumer products and detected in human serum. Our study meant to elucidate the uncovered molecular mechanisms underlying the PFOA induced colorectal cancer cell DLD-1 invasion and matrix metalloproteinases (MMP) expression. Methods and results: Trans-well filter assay appeared that PFOA treatment stimulated DLD-1 cells invasion significantly. Meanwhile, the results of luciferase reporter, quantitative real-time PCR, western blotting, and gelatin zymography showed that PFOA induced MMP-2/-9 expression and enzyme activation levels consistently (P < 0.05 each). Subsequently, western blotting and immunofluorescence assay demonstrated that PFOA could enhance nuclear factor kappaB (NF-?B) activity by stimulating NF-?B translocation into nuclear in DLD-1 cells. Furthermore, JSH-23, a well-known NF-?B inhibitor, could reverse the PFOA induced colorectal cancer cell invasion and MMP-2/-9 expression. Conclusions: Our study confirmed that PFOA could induce colorectal cancer cell DLD-1 invasive ability and MMP-2/-9 expression through activating NF-?B, which deserves more concerns on environmental pollutant-resulted public health risk. PMID:26617761

  5. Genome-wide analysis of tandem repeats in Tribolium castaneum genome reveals abundant and highly dynamic tandem repeat families with satellite DNA features in euchromatic chromosomal arms

    PubMed Central

    Pavlek, Martina; Gelfand, Yevgeniy; Plohl, Miroslav; Meštrovi?, Nevenka

    2015-01-01

    Although satellite DNAs are well-explored components of heterochromatin and centromeres, little is known about emergence, dispersal and possible impact of comparably structured tandem repeats (TRs) on the genome-wide scale. Our bioinformatics analysis of assembled Tribolium castaneum genome disclosed significant contribution of TRs in euchromatic chromosomal arms and clear predominance of satellite DNA-typical 170 bp monomers in arrays of ?5 repeats. By applying different experimental approaches, we revealed that the nine most prominent TR families Cast1–Cast9 extracted from the assembly comprise ?4.3% of the entire genome and reside almost exclusively in euchromatic regions. Among them, seven families that build ?3.9% of the genome are based on ?170 and ?340 bp long monomers. Results of phylogenetic analyses of 2500 monomers originating from these families show high-sequence dynamics, evident by extensive exchanges between arrays on non-homologous chromosomes. In addition, our analysis shows that concerted evolution acts more efficiently on longer than on shorter arrays. Efficient genome-wide distribution of nine TR families implies the role of transposition only in expansion of the most dispersed family, and involvement of other mechanisms is anticipated. Despite similarities in sequence features, FISH experiments indicate high-level compartmentalization of centromeric and euchromatic tandem repeats. PMID:26428853

  6. Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors, part 8

    NASA Technical Reports Server (NTRS)

    Brent, J. A.; Clemmons, D. R.

    1974-01-01

    An experimental investigation was conducted with an 0.8 hub/tip ratio, single-stage, axial flow compressor to determine the potential of tandem-airfoil blading for improving the efficiency and stable operating range of compressor stages. The investigation included testing of a baseline stage with single-airfoil blading and two tandem-blade stages. The overall performance of the baseline stage and the tandem-blade stage with a 20-80% loading split was considerably below the design prediction. The other tandem-blade stage, which had a rotor with a 50-50% loading split, came within 4.5% of the design pressure rise (delta P(bar)/P(bar) sub 1) and matched the design stage efficiency. The baseline stage with single-airfoil blading, which was designed to account for the actual rotor inlet velocity profile and the effects of axial velocity ratio and secondary flow, achieved the design predicted performance. The corresponding tandem-blade stage (50-50% loading split in both blade rows) slightly exceeded the design pressure rise but was 1.5 percentage points low in efficiency. The tandem rotors tested during both phases demonstrated higher pressure rise and efficiency than the corresponding single-airfoil rotor, with identical inlet and exit airfoil angles.

  7. GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators

    SciTech Connect

    Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, S.; Moriarty, T.; Romero, M. J.

    2005-08-01

    We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM, {approx}1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resulting handle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24 cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.

  8. High Energy Collisions on Tandem Time-of-Flight Mass Spectrometers

    NASA Astrophysics Data System (ADS)

    Cotter, Robert J.

    2013-05-01

    Long before the introduction of matrix-assisted laser desorption/ionization (MALDI), electrospray ionization (ESI), Orbitraps, and any of the other tools that are now used ubiquitously for proteomics and metabolomics, the highest performance mass spectrometers were sector instruments, providing high resolution mass measurements by combining an electrostatic energy analyzer (E) with a high field magnet (B). In its heyday, the four sector mass spectrometer (or EBEB) was the crown jewel, providing the highest performance tandem mass spectrometry using single, high energy collisions to induce fragmentation. During a time in which quadrupole and tandem triple quadrupole instruments were also enjoying increased usage and popularity, there were, nonetheless, some clear advantages for sectors over their low collision energy counterparts. Time-of-flight (TOF) mass spectrometers are high voltage, high vacuum instruments that have much in common with sectors and have inspired the development of tandem instruments exploiting single high energy collisions. In this retrospective, we recount our own journey to produce high performance TOFs and tandem TOFs, describing the basic theory, problems, and the advantages for such instruments. An experiment testing impulse collision theory (ICT) underscores the similarities with sector mass spectrometers where this concept was first developed. Applications provide examples of more extensive fragmentation, side chain cleavages, and charge-remote fragmentation, also characteristic of high energy sector mass spectrometers. Moreover, the so-called curved-field reflectron has enabled the design of instruments that are simpler, collect and focus all of the ions, and may provide the future technology for the clinic, for tissue imaging, and the characterization of microorganisms.

  9. Half-life of Si-32 from tandem-accelerator mass spectrometry

    NASA Technical Reports Server (NTRS)

    Elmore, D.; Anantaraman, N.; Fulbright, H. W.; Gove, H. E.; Nishiizumi, K.; Murrell, M. T.; Honda, M.; Hans, H. S.

    1980-01-01

    A newly developed mass-spectrometry technique employing a tandem Van de Graaff accelerator together with a special beam-transport system and heavy-ion detector has been used to determine the half-life of Si-32. The result obtained, 108 plus or minus 18 yr, disagrees with the accepted value of 330 plus or minus 40 yr. The implications of the new half-life of Si-32, which is used for dating studies, are discussed.

  10. Sunflower centromeres consist of a centromere-specific LINE and a chromosome-specific tandem repeat

    PubMed Central

    Nagaki, Kiyotaka; Tanaka, Keisuke; Yamaji, Naoki; Kobayashi, Hisato; Murata, Minoru

    2015-01-01

    The kinetochore is a protein complex including kinetochore-specific proteins that plays a role in chromatid segregation during mitosis and meiosis. The complex associates with centromeric DNA sequences that are usually species-specific. In plant species, tandem repeats including satellite DNA sequences and retrotransposons have been reported as centromeric DNA sequences. In this study on sunflowers, a cDNA-encoding centromere-specific histone H3 (CENH3) was isolated from a cDNA pool from a seedling, and an antibody was raised against a peptide synthesized from the deduced cDNA. The antibody specifically recognized the sunflower CENH3 (HaCENH3) and showed centromeric signals by immunostaining and immunohistochemical staining analysis. The antibody was also applied in chromatin immunoprecipitation (ChIP)-Seq to isolate centromeric DNA sequences and two different types of repetitive DNA sequences were identified. One was a long interspersed nuclear element (LINE)-like sequence, which showed centromere-specific signals on almost all chromosomes in sunflowers. This is the first report of a centromeric LINE sequence, suggesting possible centromere targeting ability. Another type of identified repetitive DNA was a tandem repeat sequence with a 187-bp unit that was found only on a pair of chromosomes. The HaCENH3 content of the tandem repeats was estimated to be much higher than that of the LINE, which implies centromere evolution from LINE-based centromeres to more stable tandem-repeat-based centromeres. In addition, the epigenetic status of the sunflower centromeres was investigated by immunohistochemical staining and ChIP, and it was found that centromeres were heterochromatic. PMID:26583020

  11. History and development of the Aerodynamic Ground Effect Craft (AGEC) with tandem wings

    NASA Astrophysics Data System (ADS)

    Joerg, G. W.

    The tandem-wing configuration aerodynamic ground effect craft (AGEC) presented are capable of fuel economies that reduce consumption to 10-15 percent of what may be expected from conventional high speed water craft. Exceptional quietness and freedom from vibrations or shocks are enjoyed by cabin occupants due to the air cushion. The catamaranlike configuration involves only a few cm of draft, allowing operations in very shallow waters. Rescue, coast guard, and mass transportation applications are envisioned.

  12. Copper-catalyzed Tandem Annulation/Arylation for the Synthesis of Diindolylmethanes from Propargylic Alcohols

    PubMed Central

    Li, Hui; Li, Xiaoxun; Wang, Hao-Yuan; Winston-McPherson, Gabrielle N.; Geng, Hao-miao Julie; Guzei, Ilia A.

    2014-01-01

    Various highly substituted 2,3?-diindolylmethane heterocycles were prepared from propargylic alcohols and indole nucleophiles via a transition metal-catalyzed tandem indole annulation/arylation reaction for the first time. Among the metal catalysts we examined, the most economical copper(I) catalyst provided the highest efficiency. The indole nucleophiles could also be replaced by other electron-rich arenes or alcohols. PMID:25178910

  13. Flow induced vibration and noise by a pair of tandem cylinders due to buffeting

    NASA Technical Reports Server (NTRS)

    Kim, C. M.; Conlisk, A. T.

    1990-01-01

    The generation of noise by vortex buffeting on a pair of cylinders in tandem in unsteady high-Reynolds-number flow is investigated analytically. The derivation of the governing equations is outlined, and numerical results for several initial vortex configurations are presented in extensive graphs and characterized in detail. Particular attention is given to the possibility of chaotic vortex motion, and it is shown that chaotic motion does not occur when there are three vortices but does appear when there are four.

  14. Tandem Duplications and the Limits of Natural Selection in Drosophila yakuba and Drosophila simulans

    PubMed Central

    Rogers, Rebekah L.; Cridland, Julie M.; Shao, Ling; Hu, Tina T.; Andolfatto, Peter; Thornton, Kevin R.

    2015-01-01

    Tandem duplications are an essential source of genetic novelty, and their variation in natural populations is expected to influence adaptive walks. Here, we describe evolutionary impacts of recently-derived, segregating tandem duplications in Drosophila yakuba and Drosophila simulans. We observe an excess of duplicated genes involved in defense against pathogens, insecticide resistance, chorion development, cuticular peptides, and lipases or endopeptidases associated with the accessory glands across both species. The observed agreement is greater than expectations on chance alone, suggesting large amounts of convergence across functional categories. We document evidence of widespread selection on the D. simulans X, suggesting adaptation through duplication is common on the X. Despite the evidence for positive selection, duplicates display an excess of low frequency variants consistent with largely detrimental impacts, limiting the variation that can effectively facilitate adaptation. Standing variation for tandem duplications spans less than 25% of the genome in D. yakuba and D. simulans, indicating that evolution will be strictly limited by mutation, even in organisms with large population sizes. Effective whole gene duplication rates are low at 1.17 × 10?9 per gene per generation in D. yakuba and 6.03 × 10?10 per gene per generation in D. simulans, suggesting long wait times for new mutations on the order of thousands of years for the establishment of sweeps. Hence, in cases where adaptation depends on individual tandem duplications, evolution will be severely limited by mutation. We observe low levels of parallel recruitment of the same duplicated gene in different species, suggesting that the span of standing variation will define evolutionary outcomes in spite of convergence across gene ontologies consistent with rapidly evolving phenotypes. PMID:26176952

  15. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W. (Golden, CO)

    2011-11-29

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  16. High-efficiency, monolithic, multi-bandgap, tandem, photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W

    2014-05-27

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  17. Neutronics shielding analysis for the end plug of a tandem mirror fusion reactor

    SciTech Connect

    Ragheb, M M.H.; Maynard, C W

    1981-01-01

    A neutronics analysis using the Monte Carlo method is carried out for the end-plug penetration and magnet system of a tandem mirror fusion reactor. Detailed penetration and magnet three-dimensional configurations are modelled. A method of position dependent angular source biasing is developed to adequately sample the DT fusion source in the central cell region and obtain flux contributions at the penetration components.

  18. Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

    SciTech Connect

    Werner, R.W.

    1982-11-01

    This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H/sub 2/SO/sub 4/-H/sub 2/O system. (MOW)

  19. Trifluoroacetic anhydride promoted tandem conjugate addition of boronic acids/acetal ring opening.

    PubMed

    Roscales, Silvia; Csáky, Aurelio G

    2012-03-01

    A new stereoselective tandem reaction consisting of the metal-free conjugate addition of boronic acids followed by an intramolecular ring opening of a cyclic acetal has been disclosed. Optically pure polysubstituted tetrahydropyrans have been synthesized diastereoselectively by this new reaction. Two new C-C bonds and up to three stereocenters are formed in a single step, allowing the generation of quaternary stereocenters. PMID:22339156

  20. Consistent in-frame internal tandem duplications of BCOR characterize clear cell sarcoma of the kidney.

    PubMed

    Ueno-Yokohata, Hitomi; Okita, Hajime; Nakasato, Keiko; Akimoto, Shingo; Hata, Jun-ichi; Koshinaga, Tsugumichi; Fukuzawa, Masahiro; Kiyokawa, Nobutaka

    2015-08-01

    Clear cell sarcoma of the kidney (CCSK) is one of the major pediatric renal neoplasms, but its associated genetic abnormalities are largely unknown. We identified internal tandem duplications in the BCOR gene (BCL6 corepressor) affecting the C terminus in 100% (20/20) of CCSK tumors but in none (0/193) of the other pediatric renal tumors. CCSK tumors expressed only an aberrant BCOR allele, indicating a close correlation between BCOR aberration and CCSK tumorigenesis. PMID:26098867

  1. Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors

    SciTech Connect

    Krikorian, O.H.

    1980-10-10

    Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.

  2. Diesel and alkane fuels from biomass by organocatalysis and metal-acid tandem catalysis.

    PubMed

    Liu, Dajiang; Chen, Eugene Y-X

    2013-12-01

    Combo deal: Biomass furaldehydes are upgraded into oxygenated diesel and high-quality C10-12 linear alkane fuels. The first of two steps involves solvent-free self-condensation (Umpolung) through organocatalysis using an N-heterocyclic carbene (NHC), yielding C10 -C12 furoin intermediates. In the metal-acid tandem catalysis step, in water, the furoin intermediates are converted into oxygenated biodiesel by hydrogenation, etherification or esterification; or into premium alkane jet fuels by hydrodeoxygenation. PMID:23939751

  3. Flight and Analytical Methods for Determining the Coupled Vibration Response of Tandem Helicopters

    NASA Technical Reports Server (NTRS)

    Yeates, John E , Jr; Brooks, George W; Houbolt, John C

    1957-01-01

    Chapter one presents a discussion of flight-test and analysis methods for some selected helicopter vibration studies. The use of a mechanical shaker in flight to determine the structural response is reported. A method for the analytical determination of the natural coupled frequencies and mode shapes of vibrations in the vertical plane of tandem helicopters is presented in Chapter two. The coupled mode shapes and frequencies are then used to calculate the response of the helicopter to applied oscillating forces.

  4. Pericyte NF-?B activation enhances endothelial cell proliferation and proangiogenic cytokine secretion in vitro

    PubMed Central

    LaBarbera, Katherine E; Hyldahl, Robert D; O'Fallon, Kevin S; Clarkson, Priscilla M; Witkowski, Sarah

    2015-01-01

    Pericytes are skeletal muscle resident, multipotent stem cells that are localized to the microvasculature. In vivo, studies have shown that they respond to damage through activation of nuclear-factor kappa-B (NF-?B), but the downstream effects of NF-?B activation on endothelial cell proliferation and cell–cell signaling during repair remain unknown. The purpose of this study was to examine pericyte NF-?B activation in a model of skeletal muscle damage; and use genetic manipulation to study the effects of changes in pericyte NF-?B activation on endothelial cell proliferation and cytokine secretion. We utilized scratch injury to C2C12 cells in coculture with human primary pericytes to assess NF-?B activation and monocyte chemoattractant protein-1 (MCP-1) secretion from pericytes and C2C12 cells. We also cocultured endothelial cells with pericytes that expressed genetically altered NF-?B activation levels, and then quantified endothelial cell proliferation and screened the conditioned media for secreted cytokines. Pericytes trended toward greater NF-?B activation in injured compared to control cocultures (P = 0.085) and in comparison to C2C12 cells (P = 0.079). Second, increased NF-?B activation in pericytes enhanced the proliferation of cocultured endothelial cells (1.3-fold, P = 0.002). Finally, we identified inflammatory signaling molecules, including MCP-1 and interleukin 8 (IL-8) that may mediate the crosstalk between pericytes and endothelial cells. The results of this study show that pericyte NF-?B activation may be an important mechanism in skeletal muscle repair with implications for the development of therapies for musculoskeletal and vascular diseases, including peripheral artery disease. PMID:25911453

  5. Suture retraction technique to prevent parent vessel obstruction following aneurysm tandem clipping.

    PubMed

    Rayan, Tarek; Amin-Hanjani, Sepideh

    2015-08-01

    With large or giant aneurysms, the use of multiple tandem clips can be essential for complete obliteration of the aneurysm. One potential disadvantage, however, is the considerable cumulative weight of these clips, which may lead to kinking of the underlying parent vessels and obstruction of flow. The authors describe a simple technique to address this problem, guided by intraoperative blood flow measurements, in a patient with a ruptured near-giant 2.2 × 1.7-cm middle cerebral artery bifurcation aneurysm that was treated with the tandem clipping technique. A total of 11 clips were applied in a vertical stacked fashion. The cumulative weight of the clips caused kinking of the temporal M2 branch of the bifurcation with reduction of flow. A 4-0 Nurolon suture tie was applied to the hub of one of the clips and was tethered to the dura of the sphenoid ridge by a small mini-clip and reinforced by application of tissue sealant. The patient underwent intraoperative indocyanine green videoangiography as well as catheter angiography, which demonstrated complete aneurysmal obliteration and preservation of vessel branches. Postoperative angiography confirmed patency of the bifurcation vessels with mild vasospasm. The patient had a full recovery with no postoperative complications and was neurologically intact at her 6-month follow-up. The suture retraction technique allows a simple solution to parent vessel obstruction following aneurysm tandem clipping, in conjunction with the essential guidance provided by intraoperative flow measurements. PMID:25723304

  6. High efficiency AlGaAs/Si tandem solar cell over 20%

    SciTech Connect

    Umeno, Masayoshi; Kato, Toshimich; Yang, Mingju; Azuma, Yutaka; Soga, Tetsuo; Jimbo, Takashi

    1994-12-31

    A high-efficiency AlGaAs/Si tandem solar cell is fabricated by metal-organic chemical vapor deposition (MOCVD). It consists of a Al{sub 0.15}Ga{sub 0.85}As top cell and a Si bottom cell. The crystalline quality of the Al{sub 0.15}Ga{sub 0.85}As heteroepitaxial layer grown on Si is improved using a high-temperature growth process (800 C) and thermal cycle annealing (300--900 C). The quantum efficiency of the Si bottom cell in the long wavelength region is improved by back surface field. The conversion efficiencies of the tandem solar cell under AMO and 1sun measurement conditions with 4-terminal and 2-terminal configuration are 20.0% and 19.0%, respectively. The conversion efficiencies of the tandem solar cell with graded-band-gap emitter Al{sub x}Ga{sub 1{minus}x}As layer achieved 20.6% and 19.9% under same condition with 4-terminal and 2-terminal configuration, respectively.

  7. Highly Transparent Dual-Sensitized Titanium Dioxide Nanotube Arrays for Spontaneous Solar Water Splitting Tandem Configuration.

    PubMed

    Shin, Kahee; Park, Jong Hyeok

    2015-08-26

    Vertically aligned one-dimensional (1D) titanium dioxide (TiO2) arrays on transparent conducting oxide (TCO) substrates, which can act as host electron transport materials for low bandgap materials, were synthesized via a hydrothermal reaction combined with a controlled chemical etching process. By controlling the chemical etching conditions, we can maximize the light transmission properties of the 1D TiO2 arrays, which is beneficial for the front electrode in photoelectrochemical (PEC) tandem configurations. As a result, dual sensitization to form 1D TiO2@CdS@CdSe (CdS and CdSe coated 1D TiO2) results in excellent photocurrent density, as well as transparency, and the resulting material is able to pass unabsorbed photons through the front electrode into the rear bias solar cell. Owing to the improved light transmission in combination with the increased specific surface area of the obtained 1D TiO2 arrays from the controlled etching process, a high-efficiency PEC tandem device with ?2.1% was successfully fabricated for unassisted hydrogen evolution. Efficient PEC tandem device was fabricated for unassisted solar hydrogen generation using highly transparent composite electrode composed of dual sensitization to form 1D TiO2@CdS@CdSe. PMID:26266330

  8. Short-pulse CO2 laser with longitudinal tandem discharge tube

    NASA Astrophysics Data System (ADS)

    Uno, K.; Akitsu, T.; Jitsuno, T.

    2014-10-01

    We developed a longitudinally excited CO2 laser with a tandem discharge tube. The tandem scheme was constituted of two 30-cm long discharge tubes connected with an intermediate electrode. Two parts, each consisting of a charged capacitance and a 30-cm long discharge tube, were electrically connected in parallel and switched by a spark gap. The tandem scheme produced a short laser pulse like that of a TEA-CO2 laser with a charging voltage of -24.8 kV, which was smaller than the -40.0 kV charging voltage of our previous CO2 laser. At a gas pressure of 3.8 kPa, the spike pulse width was 145 ns, the pulse tail length was 58.8 ?s, the output energy was 52.0 mJ, and the spike pulse energy was 2.4 mJ. We also investigated the dependence of the laser pulse and the discharge voltage on gas pressure.

  9. Atmospheric sampling glow discharge ionizataion and triple quadrupole tandem mass spectrometry for explosives vapor detection

    SciTech Connect

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.; Hart, K.J.; Glish, G.L.; Grant, B.C.; Chambers, D.M.

    1993-08-01

    The detection and identification of trace vapors of hidden high explosives is an excellent example of a targeted analysis problem. It is desirable to push to ever lower levels the quantity or concentration of explosives material that provides an analytical signal, while at the same time discriminating against all other uninteresting material. The detection system must therefore combine high sensitivity with high specificity. This report describes the philosophy behind the use of atmospheric sampling glow discharge ionization, which is a sensitive, rugged, and convenient means for forming anions from explosives molecules, with tandem mass spectrometry, which provides unparalleled specificity in the identification of explosives-related ions. Forms of tandem mass spectrometry are compared and contrasted to provide a summary of the characteristics to be expected from an explosives detector employing mass spectrometry/mass spectrometry. The instrument developed for the FAA, an atmospheric sampling glow discharge/triple quadrupole mass spectrometer, is described in detail with particular emphasis on the ion source/spectrometer interface and on the capabilities of the spectrometer. Performance characteristics of the system are also described as they pertain to explosives of interest including a description of an automated procedure for the detection and identification of specific explosives. A comparison of various tandem mass spectrometers mated with atmospheric sampling glow discharge is then described and preliminary studies with a vapor preconcentration system provided by the FAA will be described.

  10. Changes in Variable Number of Tandem Repeats in 'Candidatus Liberibacter asiaticus' through Insect Transmission.

    PubMed

    Katoh, Hiroshi; Inoue, Hiromitsu; Iwanami, Toru

    2015-01-01

    Citrus greening (huanglongbing) is the most destructive citrus disease worldwide. The disease is associated with three species of 'Candidatus Liberibacter' among which 'Ca. Liberibacter asiaticus' has the widest distribution. 'Ca. L. asiaticus' is commonly transmitted by a phloem-feeding insect vector, the Asian citrus psyllid Diaphorina citri. A previous study showed that isolates of 'Ca. L. asiaticus' were clearly differentiated by variable number of tandem repeat (VNTR) profiles at four loci in the genome. In this study, the VNTR analysis was further validated by assessing the stability of these repeats after multiplication of the pathogen upon host-to-host transmission using a 'Ca. L. asiaticus' strain from Japan. The results showed that some tandem repeats showed detectable changes after insect transmission. To our knowledge, this is the first report to demonstrate that the repeat numbers VNTR 002 and 077 of 'Ca. L. asiaticus' change through psyllid transmission. VNTRs in the recipient plant were apparently unrelated to the growing phase of the vector. In contrast, changes in the number of tandem repeats increased with longer acquisition and inoculation access periods, whereas changes were not observed through psyllid transmission after relatively short acquisition and inoculation access periods, up to 20 and 19 days, respectively. PMID:26402645

  11. Changes in Variable Number of Tandem Repeats in ‘Candidatus Liberibacter asiaticus’ through Insect Transmission

    PubMed Central

    2015-01-01

    Citrus greening (huanglongbing) is the most destructive citrus disease worldwide. The disease is associated with three species of ‘Candidatus Liberibacter’ among which ‘Ca. Liberibacter asiaticus’ has the widest distribution. ‘Ca. L. asiaticus’ is commonly transmitted by a phloem-feeding insect vector, the Asian citrus psyllid Diaphorina citri. A previous study showed that isolates of ‘Ca. L. asiaticus’ were clearly differentiated by variable number of tandem repeat (VNTR) profiles at four loci in the genome. In this study, the VNTR analysis was further validated by assessing the stability of these repeats after multiplication of the pathogen upon host-to-host transmission using a ‘Ca. L. asiaticus’ strain from Japan. The results showed that some tandem repeats showed detectable changes after insect transmission. To our knowledge, this is the first report to demonstrate that the repeat numbers VNTR 002 and 077 of ‘Ca. L. asiaticus’ change through psyllid transmission. VNTRs in the recipient plant were apparently unrelated to the growing phase of the vector. In contrast, changes in the number of tandem repeats increased with longer acquisition and inoculation access periods, whereas changes were not observed through psyllid transmission after relatively short acquisition and inoculation access periods, up to 20 and 19 days, respectively. PMID:26402645

  12. Flow-induced vibrations of two tandem circular cylinders in a parallel-wall channel

    NASA Astrophysics Data System (ADS)

    Jiang, Ren-Jie; Lin, Jian-Zhong; Ku, Xiao-Ke

    2014-10-01

    Flow-induced vibrations of one and two tandem circular cylinders in the flow around cylinders in a parallel-wall channel are numerically studied by the lattice Boltzmann method. Within a range of Reynolds number Re = [1, 160], the effects of streamwise separation between two cylinders S/D = [1.25, 3], mass ratio M = [0.05, 5], and blockage ratio ? = [1/2, 1/8] on the motions of cylinders and fluids are investigated, respectively. For the case of an isolated cylinder, as the mass ratio is 1, no large-amplitude oscillation is observed, and as the mass ratio is 0.1, the cylinder motion translates from the steady regime to the biased periodic vibration with a large oscillation amplitude gradually as Reynolds number is increased from 1 to 160. For the case of two cylinders in tandem, two steady regimes and a variety of distinct oscillation regimes with the corresponding flow structures are observed. The critical mass ratio of the two tandem cylinders in the strong coupling regime is about an order of magnitude larger than that of an isolated cylinder. For blockage ratio is more than 1/5, the vibration type of the cylinders is exclusive, while for blockage ratio is less than 1/6, the cylinder oscillation state is bistable. The mechanisms of the observed phenomena are also discussed.

  13. Control of surface thermal scratch of strip in tandem cold rolling

    NASA Astrophysics Data System (ADS)

    Chen, Jinshan; Li, Changsheng

    2014-07-01

    The thermal scratch seriously affects the surface quality of the cold rolled stainless steel strip. Some researchers have carried out qualitative and theoretical studies in this field. However, there is currently a lack of research on effective forecast and control of thermal scratch defects in practical production, especially in tandem cold rolling. In order to establish precise mathematical model of oil film thickness in deformation zone, the lubrication in cold rolling process of SUS410L stainless steel strip is studied, and major factors affecting oil film thickness are also analyzed. According to the principle of statistics, mathematical model of critical oil film thickness in deformation zone for thermal scratch is built, with fitting and regression analytical method, and then based on temperature comparison method, the criterion for deciding thermal scratch defects is put forward. Storing and calling data through SQL Server 2010, a software on thermal scratch defects control is developed through Microsoft Visual Studio 2008 by MFC technique for stainless steel in tandem cold rolling, and then it is put into practical production. Statistics indicate that the hit rate of thermal scratch is as high as 92.38%, and the occurrence rate of thermal scratch is decreased by 89.13%. Owing to the application of the software, the rolling speed is increased by approximately 9.3%. The software developed provides an effective solution to the problem of thermal scratch defects in tandem cold rolling, and helps to promote products surface quality of stainless steel strips in practical production.

  14. In vitro evaluation of the TandemHeart pediatric centrifugal pump.

    PubMed

    Svitek, Robert G; Smith, Douglas E; Magovern, James A

    2007-01-01

    The pediatric TandemHeart pump is being developed for short-term circulatory support of patients varying in size from 2 to 40 kg. The pump withdraws blood from the left atrium via cannula inserted percutaneously, either through the right internal jugular vein or transhepatically, and pumps the blood back into the arterial system via the carotid or femoral artery. High resolution stereolithography (SLA) was used to create an upper housing and impeller design, which were assembled into a functional pump prototype. Pressure-flow characteristics of the pump were determined in a blood analogue solution and compared with the pressure-flow requirements of the intended cannulation. At 5,500 rpm, the pump was able to generate 0.4 L/min of flow with a pressure rise of 325 mm Hg and 2.0 L/min with a pressure rise of 250 mm Hg. The hydraulic performance of the pump will enable at least 50% of cardiac output when the arterial cannula is placed in the carotid artery. The hemolysis of the TandemHeart pediatric pump at 5,500 rpm was compared with the BP-50 pediatric centrifugal pump in vitro using bovine blood flowing at 0.4 L/min against 250 mm Hg. The TandemHeart pump produced a similar increase in plasma free hemoglobin levels during the duration of the 6 hour test. PMID:18043160

  15. Linkage Position and Residue Identification of Disaccharides by Tandem Mass Spectrometry and Linear Discriminant Analysis

    SciTech Connect

    Hui Zhang; Steve M. Brokman; Ning Fang; Nicola L. Pohl; Edward S. Yeung

    2008-03-20

    The discrimination of isomeric disaccharides with different linkage types and different monosaccharide residues--glucose (Glc), galactose (Gal), and mannose (Man) at the non-reducing end - was investigated with tandem mass spectrometry (MS/MS) and linear discriminant analysis (LDA). Conventional matrix-assisted laser desorption/ionization (MALDI)-MS has strong interference peaks from matrix ions in the low mass region (<500 Da). This greatly limits the application of MALDI-MS for the analysis of small molecules such as saccharides. We solved this problem by using LDI with acidic fullerene matrix, which gives a very clean background in the low-mass region. Disaccharides with different linkage types give different tandem mass spectral profiles from various cross-ring fragmentation pathways. Disaccharides with the same linkage type but with three different kinds of monosaccharide residues bear the same fragmentation profiles. However, the relative ratios of the fragment ion intensities were found to be distinctly different among the three disaccharide isomers. By employing statistical tools such as LDA to classify the tandem mass spectra, disaccharide isomers with either different linkages or different monosaccharide residues were successfully classified.

  16. Linkage Position and Residue Identification of Disaccharides by Tandem mass Spectrometry and linear Discriminant Analysis

    SciTech Connect

    Hui Zhang; Steve M. Brokman; Ning Fang; Nicola L. Pohl; Edward S. Yeung

    2008-03-20

    The discrimination of isomeric disaccharides with different linkage types and different monosaccharide residues--glucose (Glc), galactose (Gal), and mannose (Man) at the non-reducing end--was investigated with tandem mass spectrometry (MS/MS) and linear discriminant analysis (LDA). Conventional matrix-assisted laser desorption/ionization (MALDI)-MS has strong interference peaks from matrix ions in the low mass region (<500 Da). This greatly limits the application of MALDI-MS for the analysis of small molecules such as saccharides. We solved this problem by using LDI with acidic fullerene matrix, which gives a very clean background in the low-mass region. Disaccharides with different linkage types give different tandem mass spectral profiles from various cross-ring fragmentation pathways. Disaccharides with the same linkage type but with three different kinds of monosaccharide residues bear the same fragmentation profiles. However, the relative ratios of the fragment ion intensities were found to be distinctly different among the three disaccharide isomers. By employing statistical tools such as LDA to classify the tandem mass spectra, disaccharide isomers with either different linkages or different monosaccharide residues were successfully classified.

  17. A polymer tandem solar cell with 10.6% power conversion efficiency

    PubMed Central

    You, Jingbi; Dou, Letian; Yoshimura, Ken; Kato, Takehito; Ohya, Kenichiro; Moriarty, Tom; Emery, Keith; Chen, Chun-Chao; Gao, Jing; Li, Gang; Yang, Yang

    2013-01-01

    An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4?eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2?,3?-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38?eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900?nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25?°C, 1,000?Wm?2, IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%. PMID:23385590

  18. A polymer tandem solar cell with 10.6% power conversion efficiency.

    PubMed

    You, Jingbi; Dou, Letian; Yoshimura, Ken; Kato, Takehito; Ohya, Kenichiro; Moriarty, Tom; Emery, Keith; Chen, Chun-Chao; Gao, Jing; Li, Gang; Yang, Yang

    2013-01-01

    An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4 eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2',3'-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm(-2), IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%. PMID:23385590

  19. Chimeric adenoviral vector Ad5/F35-mediated APE1 siRNA enhances sensitivity of human colorectal cancer cells to radiotherapy in vitro and in vivo.

    PubMed

    Xiang, D-B; Chen, Z-T; Wang, D; Li, M-X; Xie, J-Y; Zhang, Y-S; Qing, Y; Li, Z-P; Xie, J

    2008-10-01

    Apurinic/apyrimidinic endonuclease (APE1), a bifunctional AP endonuclease/redox factor, is important in DNA repair and redox signaling, may be associated with radioresistance. Here we investigate whether targeted inhibition of APE1 can sensitize tumor cells to irradiation in vitro and in vivo. We first constructed chimeric adenoviral vector Ad5/F35 carrying human APE1 siRNA (Ad5/F35-APE1 siRNA). The infectivity of chimeric Ad5/F35 to LOVO colon cancer cells was greater than that of Ad5. APE1 was strongly expressed and nuclear factor kappaB (NF-kappaB), a downstream molecule of APE1, known as a radioresistance factor, was constitutively active in LOVO cells. Infection of LOVO cells with Ad5/F35-APE1 siRNA resulted in a dose-dependent decrease of APE1 protein and AP endonuclease activity in vitro. Ad5/F35-APE1 siRNA significantly enhanced sensitivity of LOVO cells to irradiation in clonogenic survival assays, associated with increased cell apoptosis. The APE1 expression in LOVO cells was induced by irradiation in a dose-dependent manner, accompanied with the enhancement of DNA-binding activity of NF-kappaB and Ad5/F35-APE1 siRNA effectively inhibited constitutive and irradiation-induced APE1 expression and NF-kappaB activation. In a subcutaneous nude mouse colon cancer model, Ad5/F35-APE1 siRNA (5 x 10(8) IU, intratumoral injection) inhibited the expression of APE1 protein in LOVO xenografts, and significantly enhanced inhibition of tumor growth by irradiation. In conclusion, APE1 may be involved as one of the radioresistance factors, and targeted inhibition of APE1 shows an effective means of enhancing tumor sensitivity to radiotherapy. PMID:18535621

  20. High efficiency a-Si:H/a-SiGe:H tandem solar cells fabricated with the combination of V- and U-shaped band gap profiling techniques

    NASA Astrophysics Data System (ADS)

    Inthisang, Sorapong; Krajangsang, Taweewat; Hongsingthong, Aswin; Limmanee, Amornrat; Kittisontirak, Songkiate; Jaroensathainchok, Suttinan; Moolakorn, Apichan; Dousse, Adrien; Sritharathikhun, Jaran; Sriprapha, Kobsak

    2015-08-01

    Hydrogenated amorphous silicon germanium (a-SiGe:H) films prepared by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) using a mixture of SiH4, H2, and GeH4 were investigated for their use as the bottom cell of amorphous silicon/amorphous silicon germanium (a-Si:H/a-SiGe:H) tandem solar cell structures. Narrow optical band gaps (Eopt) in the range of 1.5 to 1.6 eV were obtained by varying the GeH4/(SiH4 + GeH4) gas flow rate ratio in low-temperature deposition. The a-SiGe:H films deposited with various GeH4/(SiH4 + GeH4) gas flow rate ratios were used as intrinsic layers for the a-Si:H/a-SiGe:H tandem solar cells with different graded band gaps: V-, VU-, and U-shapes. It was found that using the VU-shape improves the solar cell efficiency owing to a higher Jsc when compared with using V-shape. The VU-shape’s Voc and FF are also improved when compared with the U-shape’s Voc and FF. As a result, a high efficiency of 11.0% (Voc = 1.74 V, Jsc = 9.07 mA/cm2, and FF = 0.70) was successfully achieved with the solar cells fabricated using the VU-shape graded band gap technique.

  1. Controlling the Morphology of BDTT-DPP-Based Small Molecules via End-Group Functionalization for Highly Efficient Single and Tandem Organic Photovoltaic Cells.

    PubMed

    Kim, Ji-Hoon; Park, Jong Baek; Yang, Hoichang; Jung, In Hwan; Yoon, Sung Cheol; Kim, Dongwook; Hwang, Do-Hoon

    2015-11-01

    A series of narrow-band gap, ?-conjugated small molecules based on diketopyrrolopyrrole (DPP) electron acceptor units coupled with alkylthienyl-substituted-benzodithiophene (BDTT) electron donors were designed and synthesized for use as donor materials in solution-processed organic photovoltaic cells. In particular, by end-group functionalization of the small molecules with fluorine derivatives, the nanoscale morphologies of the photoactive layers of the photovoltaic cells were successfully controlled. The influences of different fluorine-based end-groups on the optoelectronic and morphological properties, carrier mobilities, and the photovoltaic performances of these materials were investigated. A high power conversion efficiency (PCE) of 6.00% under simulated solar light (AM 1.5G) illumination has been achieved for organic photovoltaic cells based on a small-molecule bulk heterojunction system consisting of a trifluoromethylbenzene (CF3) end-group-containing oligomer (BDTT-(DPP)2-CF3) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. As a result, the introduction of CF3 end-groups has been found to enhance both the short circuit current density (JSC) and fill factor (FF). A tandem photovoltaic device comprising an inverted BDTT-(DPP)2-CF3:PC71BM cell and a poly(3-hexylthiophene) (P3HT):indene-C60-bisadduct (IC60BA)-based cell as the top and bottom cell components, respectively, showed a maximum PCE of 8.30%. These results provide valuable guidelines for the rational design of conjugated small molecules for applications in high-performance organic photovoltaic cells. Furthermore, to the best of our knowledge, this is the first report on the design of fluorine-functionalized BDTT-DPP-based small molecules, which have been shown to be a viable candidate for use in inverted tandem cells. PMID:26457421

  2. Neonatal Screening of Inborn Errors of Metabolism Using Tandem Mass Spectrometry

    PubMed Central

    2003-01-01

    Executive Summary Objectives and Method The Medical Advisory Secretariat undertook a review of the evidence on the effectiveness and cost-effectiveness of using tandem mass spectrometer [MS/MS] for the neonatal screening of inborn errors of metabolism [IEM]. The review is based on two systematic reviews commissioned by the National Health Services (United Kingdom) and relevant research literature that was published after the completion of these two systematic reviews. A horizon scanning was conducted to determine the current status of neonatal screening programs in other national and international jurisdictions. The MAS also consulted with stakeholders including the laboratory branch, an expert in IEM at a pediatric hospital, MS/MS experts and a MS/MS manufacturer. Result Synthesis of information obtained from the above process showed that: Ontario is currently screening all newborns for phenylketonuria [PKU] and congenital hypothyroidism [CH] using the Guthrie method on dry blood spots obtained by heel prick before discharge from hospital. MS/MS can detect 25 IEMs in a single process on the same dry blood spot. Computer algorithms have been used to automate the MS/MS screening process to provide rapid throughputs of 400 samples or more per day. Screening for additional IEMs using MS/MS does not add significant cost to the program. MS/MS -based neonatal screening showed sensitivity of 100% and specificity of 83% to 99% depending on the IEM. The specificity of MS/MS in detecting PKU is significantly superior to that of the current Guthrie method and is therefore able to reduce the number of false positive results. For certain inborn errors of metabolism not currently screened, early detection and simple treatment could avoid early mortality and prevent or reduce mental retardation Using eligibility criteria recommended by the World Health Organization adapted to Ontario, a rating system was developed and applied to assess the IEMs recommended for inclusion in neonatal screening. The assessment showed that PKU and CH should continued to be screened. In addition, medium chain acyl-CoA dehydrogenase deficiency [MCADD] and congenital adrenal hyperplasia [CAH] met most of the criteria for inclusion in a neonatal screening program. MCADD can be screened with PKU by MS/MS while the test for CAH requires a different methodology. An expanded neonatal program would require an enhanced infrastructure for result interpretation, reporting, care provision and counseling. Important ethical and societal issues including informed consent need to be addressed. As of 1998, twenty-six states in the United States were using MS/MS for newborn screening of IEMs. In Canada, British Columbia, Saskatchewan and Nova Scotia use MS/MS for IEM related assays. Manitoba is planning to implement MS/MS -based neonatal screening in 2003. Among Canadian jurisdictions, British Columbia, Manitoba, Quebec, Nova Scotia and Saskatchewan are screening for more IEMs than Ontario. PMID:23074443

  3. Simultaneous analysis of buprenorphine, methadone, cocaine, opiates and nicotine metabolites in sweat by liquid chromatography tandem mass spectrometry

    PubMed Central

    Concheiro, Marta; Shakleya, Diaa M.

    2013-01-01

    A liquid chromatography tandem mass spectrometry method for buprenorphine (BUP), norbuprenorphine (NBUP), methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylecgonine, ecgonine methyl ester (EME), morphine, codeine, 6-acetylmorphine, heroin, 6-acetylcodeine, cotinine, and trans-3?-hydroxycotinine quantification in sweat was developed and comprehensively validated. Sweat patches were mixed with 6 mL acetate buffer at pH 4.5, and supernatant extracted with Strata-XC-cartridges. Reverse-phase separation was achieved with a gradient mobile phase of 0.1% formic acid and acetonitrile in 15 min. Quantification was achieved by multiple reaction monitoring of two transitions per compound. The assay was a linear 1–1,000 ng/patch, except EME 5–1,000 ng/patch. Intra-, inter-day and total imprecision were <10.1%CV, analytical recovery 87.2–107.7%, extraction efficiency 35.3– 160.9%, and process efficiency 25.5–91.7%. Ion suppression was detected for EME (?63.3%) and EDDP (?60.4%), and enhancement for NBUP (42.6%). Deuterated internal standards compensated for these effects. No carryover was detected, and all analytes were stable for 24 h at 22 °C, 72 h at 4 °C, and after three freeze/thaw cycles. The method was applied to weekly sweat patches from an opioid-dependent BUP-maintained pregnant woman; 75.0% of sweat patches were positive for BUP, 93.8% for cocaine, 37.5% for opiates, 6.3% for methadone and all for tobacco biomarkers. This method permits a fast and simultaneous quantification of 14 drugs and metabolites in sweat patches, with good selectivity and sensitivity. PMID:21125263

  4. Comparison of genetic structures and biochemical properties of tandem cutinase-type polyesterases from Thermobifida alba AHK119.

    PubMed

    Thumarat, Uschara; Kawabata, Takeshi; Nakajima, Maho; Nakajima, Hajime; Sugiyama, Akifumi; Yazaki, Kazufumi; Tada, Tomoko; Waku, Tomonori; Tanaka, Naoki; Kawai, Fusako

    2015-11-01

    This study described the genetic map of tandem genes (est1 and est119) encoding cutinase-type polyesterases in Thermobifida alba AHK119 and comparison of wild type and mutant enzymes of Est1 and Est119. Two genes were independently and constitutively expressed. The activity of Est1 was higher by approximately 1.6-1.7-fold than that of Est119 towards p-nitrophenyl butyrate, although both enzymes shared 95% sequence identity and 98% similarity and possessed similar 3D structures except that several amino acids in the probable substrate-docking loops were different from each other. Calcium ion enhanced the activity and the thermostability of both enzymes. Based on conserved sequences among Thermobifida cutinases, valine, proline and lysine were introduced into Est1 at Ala68, Thr253 and Met256, respectively. Among wild and mutant enzymes of Est119 and Est1, Est1 (A68V/T253P) possessed three prolines in the substrate-docking loops and displayed the highest thermostability that spotlighted the important effect of proline numbers in the loops. Est1 (A68V/T253P) was stable for 1 h below 60°C and even at 65°C, more than 70% and 50% activities were maintained after 30 and 60 min, respectively. Est1 (A68V/T253P) degraded various aliphatic and aliphatic-co-aromatic polyesters and hydrophilized an amorphous PET film. The enzyme hydrolyzed a PET trimer model compound, indicating its specificity towards an ester bond between terephthalic acid and ethylene glycol. PMID:25910960

  5. Rapid analysis of pharmaceuticals and personal care products in fish plasma micro-aliquots using liquid chromatography tandem mass spectrometry.

    PubMed

    Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

    2015-02-27

    A sensitive analytical method based on liquid-liquid extraction (LLE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for rapid analysis of 11 pharmaceuticals and personal care products (PPCPs) in fish plasma micro-aliquots (?20?L). Target PPCPs included, bisphenol A, carbamazepine, diclofenac, fluoxetine, gemfibrozil, ibuprofen, naproxen, risperidone, sertraline, simvastatin and triclosan. A relatively quicker and cheaper LLE procedure exhibited comparable analyte recoveries with solid-phase extraction. Rapid separation and analysis of target compounds in fish plasma extracts was achieved by employing a high efficiency C-18 HPLC column (Agilent Poroshell 120 SB-C18, 2.1mm×50mm, 2.7?m) and fast polarity switching, enabling effective monitoring of positive and negative ions in a single 9min run. With the exception of bisphenol A, which exhibited relatively high background contamination, method detection limits of individual PPCPs ranged between 0.15 and 0.69pg/?L, while method quantification limits were between 0.05 and 2.3pg/?L. Mean matrix effect (ME) values ranged between 65 and 156% for the various target analytes. Isotope dilution quantification using isotopically labelled internal surrogates was utilized to correct for signal suppression or enhancement and analyte losses during sample preparation. The method was evaluated by analysis of 20?L plasma micro-aliquots collected from zebrafish (Danio rerio) from a laboratory bioaccumulation study, which included control group fish (no exposure), as well as fish exposed to environmentally relevant concentrations of PPCPs. Using the developed LC-MS/MS based method, concentrations of the studied PPCPs were consistently detected in the low pg/?L (ppb) range. The method may be useful for investigations requiring fast, reliable concentration measurements of PPCPs in fish plasma. In particular, the method may be applicable for in situ contaminant biomonitoring, as well as bioaccumulation and toxicology studies employing small fishes with low blood compartment volumes. PMID:25640994

  6. Ultra-performance liquid chromatography tandem mass spectrometry for the rapid simultaneous analysis of nine organophosphate esters in milk powder.

    PubMed

    Guo, Xindong; Mu, Tongna; Xian, Yanping; Luo, Donghui; Wang, Chao

    2016-04-01

    Organophosphate esters (OPEs) are common flame retardants that are used in a wide variety of products. These compounds might migrate into and pollute food products. An analytical method involving an improved approach called the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed to simultaneously measure trace levels of nine OPEs in milk powder. Separation of the nine OPEs was optimized on a reversed-phase column within 7min. The stable isotope tri-n-butyl phosphate-d27 (TBP-d27) was used as an internal standard. This method was validated in terms of its linearity, sensitivity, precision, accuracy and matrix effects. Matrix-matched calibration curves were constructed with 1/x(2) as the weighting factor for all of the target compounds resulting in coefficients of regression lines between 0.9938 and 0.9999. The average accuracy was between 73.5% and 110.2%. Intra- and inter-assay precisions for six replicates ranged from 3.9% to 8.9% or below 11%, respectively. The limits of detection (LODs) were in the range of 0.1-0.25?g/kg, and the limits of quantification (LOQs) were below 1.5?g/kg. Significant matrix effects have been observed, but suppression or enhancement of the signal was compensated for by the use of an isotopically labeled internal standard. This validated method was successfully applied to determine the concentrations of the OPEs in milk powder. PMID:26593541

  7. Optimal design of high-efficiency single-junction and tandem concentrator space cells at 80 deg C and 100 SUNS

    NASA Technical Reports Server (NTRS)

    Fan, J. C. C.; Palm, B. J.

    1984-01-01

    Computer analysis was used to determine the AMO conversion efficiency of single-junction crystalline cells, two-cell and three-cell crystalline tandem structures operating under 100 suns and at 80 C. For optimally designed devices, the calculated efficiencies are 24% for single-junction cells, 33 to 35% for two-cell tandem structures, and 37 to 39% for three-cell tandem structures. Practical efficiencies are expected to be about 15 relative percentage points lower in each case.

  8. A variable tandem repeat locus mapped to chromosome band 10q26 is amplified and rearranged in leukocyte DNAs of two cancer patients.

    PubMed Central

    Colb, M; Yang-Feng, T; Francke, U; Mermer, B; Parkinson, D R; Krontiris, T G

    1986-01-01

    A highly polymorphic locus associated with the variable tandem repetition of a 35 bp consensus sequence was mapped to chromosome 10, band q26. Examination of leukocyte DNA from a cancer patient revealed the twenty-fold amplification of one allelic fragment of this locus, while the other allelic fragment demonstrated a normal copy number. In another patient, Southern blotting of leukocyte DNA detected the deletion of the 3'-flanking region from one tandem repeat allele. These results indicate that variable tandem repeats may mark highly unstable regions of DNA in the human genome which can be altered by changes more extensive than simple tandem repeat variation. Images PMID:3022240

  9. Determination of imatinib and its active metabolite N-desmethyl imatinib in human plasma by liquid chromatography/tandem mass spectrometry.

    PubMed

    Zhang, Mei; Moore, Grant A; Fernyhough, Liam J; Barclay, Murray L; Begg, Evan J

    2012-10-01

    Imatinib is a first-line treatment for chronic myelogenous leukaemia (CML). The pharmacokinetics of imatinib in patients with CML are characterised by large interpatient variability. Concentration monitoring of imatinib and its active metabolite N-desmethyl imatinib (DMI) is considered necessary to enhance the safe and effective use of imatinib. A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry assay was developed for the simultaneous determination of imatinib and its metabolite DMI in human plasma. After proteins were precipitated with acetonitrile, imatinib, DMI and the internal standard D8-imatinib were resolved on a Gemini-NX 3 ?m C18 column using gradient elution of 0.05 % formic acid and methanol. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves of imatinib and DMI were adequately fitted by quadratic equations (r > 0.999) over the concentration range of 10 to 2,000 ng/mL which encompasses clinical concentrations. Bias was ?±8.3 %, intra- and inter-day coefficients of variation (imprecision) were ?8.0 % and the limit of quantification was 10 ng/mL for both imatinib and DMI. The assay is being used successfully in clinical practice to enhance the safe and effective use of imatinib. PMID:22865010

  10. Comprehensive analysis of nonenzymatic post-translational ?-lactoglobulin modifications in processed milk by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Meltretter, Jasmin; Wüst, Johannes; Pischetsrieder, Monika

    2013-07-17

    Nonenzymatic post-translational protein modifications (nePTMs) result in changes of the protein structure that may severely influence physiological and technological protein functions. In the present study, ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) was applied for the systematic identification and site-specific analysis of nePTMs of ?-lactoglobulin in processed milk. For this purpose, ?-lactoglobulin, which had been heated with lactose under conditions to force nePTM formation (7 d/60 °C), was screened for predicted modifications by using full scans and enhanced resolution scan experiments combined with enhanced product ion scans. Thus, the main glycation, glycoxidation, oxidation, and deamidation products of lysine, arginine, methionine, cysteine, tryptophan, and asparagine, as well as the N-terminus, were identified. Using these MS data, a very sensitive scheduled multiple reaction monitoring method suitable for the analysis of milk products was developed. Consequently, 14 different PTM structures on 25 binding sites of ?-lactoglobulin were detected in different milk products. PMID:23772976

  11. EDITORIAL: Enhancing nanolithography Enhancing nanolithography

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2012-01-01

    Lithography was invented in late 18th century Bavaria by an ambitious young playwright named Alois Senefelder. Senefelder experimented with stone, wax, water and ink in the hope of finding a way of reproducing text so that he might financially gain from a wider distribution of his already successful scripts. His discovery not only facilitated the profitability of his plays, but also provided the world with an affordable printing press that would ultimately democratize the dissemination of art, knowledge and literature. Since Senefelder, experiments in lithography have continued with a range of innovations including the use of electron beams and UV that allow increasingly higher-resolution features [1, 2]. Applications for this have now breached the limits of paper printing into the realms of semiconductor and microelectronic mechanical systems technology. In this issue, researchers demonstrate a technique for fabricating periodic features in poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) [3]. Their method combines field enhancements from silica nanospheres with laser-interference lithography to provide a means of patterning a polymer that has the potential to open the market of low-end, high-volume microelectronics. Laser-interference lithography has already been used successfully in patterning. Researchers in Korea used laser-interference lithography to generate stamps for imprinting a two-dimensional photonic crystal structure into green light emitting diodes (LEDs) [4]. The imprinted patterns comprised depressions 100 nm deep and 180 nm wide with a periodicity of 295 nm. In comparison with unpatterned LEDs, the intensity of photoluminescence was enhanced by a factor of seven in the LEDs that had the photonic crystal structures imprinted in them. The potential of exploiting field enhancements around nanostructures for new technologies has also attracted a great deal of attention. Researchers in the USA and Australia have used the field enhancements around an array of nanorods to improve the operation of a Schottky diode device operating in reverse bias. The diode is used for gas sensing, an application that also benefits from the high surface to volume ratio of nanostructures for gas adsorption [5]. Enhancing the electric field is also hugely advantageous for Raman spectroscopy. The vibrational modes probed with Raman spectroscopy provide a useful, highly distinctive molecular signature but the signal is weak. An array of nanoneedles fabricated by researchers in China and Japan has demonstrated controllable and repeatable enhancements to Raman signals of 108 [6]. Researchers in the UK have demonstrated how the field enhancements resulting from the plasmonic properties of metal nanoparticles can be tuned to carefully manipulate their effect on the fluorescence intensity, lifetime and Raman signal from nearby fluorophores. They also successfully decoupled the effects on radiative and non-radiative decay and shed light on the hot spots present in surface-enhanced Raman spectroscopy measurements. Plasmonics has enormous potential in the field of optoelectronics. In recognition of the fertility of research in this field, Nanotechnology will publish a special issue on plasmonics in optoeletronics later this year. The work of Suman Das and colleagues in the USA and Germany reported in this issue combines both field enhancements and laser-interference lithography to impart a nanoporous structure to a polymer with high industrial potential. PEDOT-PSS has high conductivity and is also moderately transparent, making it eligible for transparent conductors in electroluminescent devices, conducting layers in capacitors, photovoltaic cells and sensors. It has also been considered recently for bioelectronic applications, in particular neuronal cell signalling and neural interfaces, as a result of its electronic and ionic conductivity. The researchers irradiated a monolayer of silica nanospheres on a film of PEDOT-PSS with interfering laser beams. The interference gave rise to a periodic line-like pattern in the i

  12. Transcription of the hypersensitive site HS2 enhancer in erythroid cells

    SciTech Connect

    Tuan, D.; Suming Kong; Hu, K. )

    1992-12-01

    In the human genome, the erythroid-specific hypersensitive site HS2 enhancer regulates the transcription of the downstream [beta]-like globin genes 10-50 kilobases away. The mechanism of HS2 enhancer function is not known. The present study employs RNA protection assays to analyze the transcriptional status of the HS2 enhancer in transfected recombinant chloramphenicol acetyltransferase (CAT) plasmids. In erythroid K562 cells in which the HS2 enhancer is active, the HS2 sequence directs the synthesis of long enhancer transcripts that are initiated apparently from within the enhancer and elongated through the intervening DNA into the cis-linked CAT gene. In nonerythroid HL-60 cells in which the HS2 enhancer is inactive, long enhancer transcripts are not detectable. Splitting the HS2 enhancer between two tandem Ap1 sites abolishes the synthesis of a group of long enhancer transcripts and results in loss of enhancer function and transcriptional silencing of the cis-linked CAT gene. In directing the synthesis of RNA through the intervening DNA and the gene by a tracking and transcription mechanism, the HS2 enhancer may (i) open up the chromatin structure of a gene domain and (ii) deliver enhancer binding proteins to the promoter sequence where they may stimulate the transcription of the gene at the cap site. 42 refs., 4 figs., 1 tab.

  13. Comparison of tandem-in-space and tandem-in-time mass spectrometry in gas chromatography determination of pesticides: application to simple and complex food samples.

    PubMed

    Garrido Frenich, A; Plaza-Bolaños, P; Martínez Vidal, J L

    2008-09-01

    Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) is one of the most powerful techniques in pesticide residue analysis. MS/MS can be conceived in two ways: tandem in space (e.g. triple quadrupole, QqQ) or in time (e.g. ion trap, IT). QqQ and IT are commonly interfaced to GC; however, there has not been any direct comparison between them in pesticide residue analysis so far. In the present work, the performance of GC coupled to these two analyzers (GC-QqQ-MS/MS and GC-IT-MS/MS) was studied and compared for pesticide residue analysis as well as its application in food analysis. The large volume injection (LVI) technique together with programmed-temperature vaporization (PTV) was applied. For this purpose, 19 pesticides, including organochlorine and organophophorus pesticides and pyrethroids, were analyzed in both systems. Mass spectrometric data, performance characteristics (linearity, intra-day and inter-day precision) and the influence of the matrix nature on the analysis of low concentrations were compared. The target compounds were analyzed in solvent and in two representative food matrices such as cucumber (high water content) and egg (high fat content). MS data and intra-day precision were similar in QqQ and IT, whereas inter-day precision was significantly worse in QqQ. Linearity (expressed as determination coefficient, R(2)) in the range 10-150 microg L(-1) was adequate in both systems; however, better R(2) values were obtained with the QqQ analyzer in high and low concentration ranges (1-50 and 1-750 microg L(-1), respectively). The influence of the matrix nature on the analysis of low concentrations of each analyzer was also evaluated. The QqQ and IT performance was similar in cucumber and solvent. However, QqQ provided better sensitivity in egg working in selected reaction monitoring (SRM). PMID:18667209

  14. Photon management for enhanced open-circuit voltage in nanostructured solar cells

    NASA Astrophysics Data System (ADS)

    Sandhu, S.; Yu, Z.; Fan, S.

    2015-10-01

    We review the recent progress on using pure photonic engineering for voltage enhancement of nanostructured solar cells. These works use a detailed balance analysis for the current-voltage modeling of their devices, while taking into account of intrinsic material nonidealities to determine their fundamental limiting performances. The physics of voltage enhancement in these nanostructures is elucidated and shown to be related to the suppression of thermal emission in the immediate vicinity of the material electronic bandgap. We also review a recent work on using thermal emission suppresion in a single material tandem cell configuration to overcome the Shockley-Queisser limit.

  15. Bifacial Si heterojunction-perovskite organic-inorganic tandem to produce highly efficient ( ?T * ˜ 33%) solar cell

    NASA Astrophysics Data System (ADS)

    Asadpour, Reza; Chavali, Raghu V. K.; Ryyan Khan, M.; Alam, Muhammad A.

    2015-06-01

    As single junction photovoltaic (PV) technologies, both Si heterojunction (HIT) and perovskite based solar cells promise high efficiencies at low cost. Intuitively, a traditional tandem cell design with these cells connected in series is expected to improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics, however, we find that a traditional series connected tandem design suffers from low J S C due to band-gap mismatch and current matching constraints. Specifically, a traditional tandem cell with state-of-the-art HIT ( ? = 24 % ) and perovskite ( ? = 20 % ) sub-cells provides only a modest tandem efficiency of ? T ˜ 25%. Instead, we demonstrate that a bifacial HIT/perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration, the same state-of-the-art sub-cells achieve a normalized output of ?T * = 33%, exceeding the bifacial HIT performance at practical albedo reflections. Unlike the traditional design, this bifacial design is relatively insensitive to perovskite thickness variations, which may translate to simpler manufacture and higher yield.

  16. Enhancing bioremediation

    SciTech Connect

    Koenigsberg, S.

    1997-02-01

    Oxygen is often the limiting factor in aerobic bioremediation. Without adequate oxygen, contaminant degradation will either cease or proceed by highly inefficient anaerobic processes. Researchers at Regenesis Bioremediation Products recently develope a technology to combat this problem, Oxygen Release Compound (ORC) a unique formulation of magnesium peroxide release oxygen slowly when hydrated. ORC is idea for supporting bioremediation of underground storage tank releases. ORC treatment represents a low intensity approach to remediation - simple, passive, low-cost, long term enhancement of a natural attenuation. 1 fig.

  17. Flexible micromorph tandem a-Si/{mu}c-Si solar cells

    SciTech Connect

    Soederstroem, T.; Haug, F.-J.; Terrazzoni-Daudrix, V.; Ballif, C.

    2010-01-15

    The deposition of a stack of amorphous (a-Si:H) and microcrystalline ({mu}c-Si:H) tandem thin film silicon solar cells (micromorph) requires at least twice the time used for a single junction a-Si:H cell. However, micromorph devices have a higher potential efficiency, thanks to the broader absorption spectrum of {mu}c-Si:H material. High efficiencies can only be achieved by mitigating the nanocracks in the {mu}c-Si:H cell and the light-induced degradation of the a-Si:H cell. As a result, {mu}c-Si:H cell has to grow on a smooth substrate with large periodicity (>1 {mu}m) and the a-Si:H cell on sharp pyramids with smaller feature size ({approx}350 nm) to strongly scatter the light in the weak absorption spectra of a-Si:H material. The asymmetric intermediate reflector introduced in this work uncouples the growth and light scattering issues of the tandem micromorph solar cells. The stabilized efficiency of the tandem n-i-p/n-i-p micromorph is increased by a relative 15% compared to a cell without AIR and 32% in relative compared to an a-Si:H single junction solar cells. The overall process (T<200 deg. C) is kept compatible with low cost plastic substrates. The best stabilized efficiency of a cell deposited on polyethylene-naphthalate plastic substrate is 9.8% after 1000 h of light soaking at V{sub oc}, 1 sun, and 50 deg. C.

  18. High resolution DEM from Tandem-X interferometry: an accurate tool to characterize volcanic activity

    NASA Astrophysics Data System (ADS)

    Albino, Fabien; Kervyn, Francois

    2013-04-01

    Tandem-X mission was launched by the German agency (DLR) in June 2010. It is a new generation high resolution SAR sensor mainly dedicated to topographic applications. For the purpose of our researches focused on the study of the volcano-tectonic activity in the Kivu Rift area, a set of Tandem-X bistatic radar images were used to produce a high resolution InSAR DEM of the Virunga Volcanic Province (VVP). The VVP is part of the Western branch of the African rift, situated at the boundary between D.R. Congo, Rwanda and Uganda. It has two highly active volcanoes, Nyiragongo and Nyamulagira. A first task concerns the quantitative assessment of the vertical accuracy that can be achieved with these new data. The new DEMs are compared to other space borne datasets (SRTM, ASTER) but also to field measurements given by differential GPS. Multi-temporal radar acquisitions allow us to produce several DEM of the same area. This appeared to be very useful in the context of an active volcanic context where new geomorphological features (faults, fissures, volcanic cones and lava flows) appear continuously through time. For example, since the year 2000, time of the SRTM acquisition, we had one eruption at Nyiragongo (2002) and six eruptions at Nyamulagira (2001, 2002, 2004, 2006, 2010 and 2011) which all induce large changes in the landscape with the emplacement of new lava fields and scoria cones. From our repetitive Tandem-X DEM production, we have a tool to identify and also quantify in term of size and volume all the topographic changes relative to this past volcanic activity. These parameters are high value information to improve the understanding of the Virunga volcanoes; the accurate estimation of erupted volume and knowledge of structural features associated to past eruptions are key parameters to understand the volcanic system, to ameliorate the hazard assessment, and finally contribute to risk mitigation in a densely populated area.

  19. Force measurements of flexible tandem wings in hovering and forward flights.

    PubMed

    Zheng, Yingying; Wu, Yanhua; Tang, Hui

    2015-01-01

    Aerodynamic forces, power consumptions and efficiencies of flexible and rigid tandem wings undergoing combined plunging/pitching motion were measured in a hovering flight and two forward flights with Strouhal numbers of 0.6 and 0.3. Three flexible dragonfly-like tandem wing models termed Wing I, Wing II, and Wing III which are progressively less flexible, as well as a pair of rigid wings as the reference were operated at three phase differences of 0°, 90° and 180°. The results showed that both the flexibility and phase difference have significant effects on the aerodynamic performances. In both hovering and forward flights at a higher oscillation frequency of 1 Hz (St = 0.6), the Wing III model outperformed the other wing models with larger total horizontal force coefficient and efficiency. In forward flight at the lower frequency of 0.5 Hz (St = 0.3), Wing III, rigid wings and Wing II models performed best at 0°, 90° and 180° phase difference, respectively. From the time histories of force coefficients of fore- and hind-wings, different peak values, phase lags, and secondary peaks were found to be the important reasons to cause the differences in the average horizontal force coefficients. Particle image velocimetry and deformation measurements were performed to provide the insights into how the flexibility affects the aerodynamic performance of the tandem wings. The spanwise bending deformation was found to contribute to the horizontal force, by offering a more beneficial position to make LEV more attached to the wing model in both hovering and forward flights, and inducing a higher-velocity region in forward flight. PMID:25656164

  20. Advanced photovoltaic power systems using tandem GaAs/GaSb concentrator modules

    NASA Technical Reports Server (NTRS)

    Fraas, L. M.; Kuryla, M. S.; Pietila, D. A.; Sundaram, V. S.; Gruenbaum, P. E.; Avery, J. E.; Dihn, V.; Ballantyne, R.; Samuel, C.

    1992-01-01

    In 1989, Boeing announced the fabrication of a tandem gallium concentrator solar cell with an energy conversion efficiency of 30 percent. This research breakthrough has now led to panels which are significantly smaller, lighter, more radiation resistant, and potentially less expensive than the traditional silicon flat plate electric power supply. The new Boeing tandem concentrator (BTC) module uses an array of lightweight silicone Fresnel lenses mounted on the front side of a light weight aluminum honeycomb structure to focus sunlight onto small area solar cells mounted on a thin back plane. This module design is shown schematically. The tandem solar cell in this new module consists of a gallium arsenide light sensitive cell with a 24 percent energy conversion efficiency stacked on top of a gallium antimonide infrared sensitive cell with a conversion efficiency of 6 percent. This gives a total efficiency 30 percent for the cell-stack. The lens optical efficiency is typically 85 percent. Discounting for efficiency losses associated with lens packing, cell wiring, and cell operating temperature still allows for a module efficiency of 22 percent which leads to a module power density of 300 Watts/sq. m. This performance provides more than twice the power density available from a single crystal silicon flat plate module and at least four times the power density available from amorphous silicon modules. The fact that the lenses are only 0.010 ft. thick and the aluminum foil back plane is only 0.003 ft. thick leads to a very lightweight module. Although the cells are an easy to handle thickness of 0.020 ft., the fact that they are small, occupying one-twenty-fifth of the module area, means that they add little to the module weight. After summing all the module weights and given the high module power, we find that we are able to fabricate BTC modules with specific power of 100 watts/kg.