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1

Interactions at a dioxin responsive element (DRE) and an overlapping kappaB site within the hs4 domain of the 3'alpha immunoglobulin heavy chain enhancer.  

PubMed

Our previous results describing the CH12.LX (AhR-expressing) and BCL-1 (AhR-deficient) B cell lines have supported an AhR/dioxin-responsive element (DRE)-mediated mechanism for TCDD-induced inhibition of micro heavy chain expression and thus of IgM secretion. Transcriptional regulation of the Ig heavy chain genes involves several regulatory elements including the 3'alpha Ig heavy chain enhancer, which is composed of four regulatory domains that span approximately 40 kb. One of these domains, hs4, contains a DRE-like site that overlaps a kappaB motif. We have previously demonstrated TCDD-inducible binding of both the AhR nuclear complex and NF-kappaB/Rel proteins to the DRE and kappaB motifs, respectively, as well as TCDD and LPS-induced transcriptional activity through the hs4 domain. The objective of the present study was to determine if the AhR nuclear complex and NF-kappaB/Rel proteins converge at these two overlapping cis-elements and act cooperatively to influence enhancer activity. To eliminate the potential influence of other transcription factors which bind to the hs4 domain, the approach was to construct a series of luciferase reporters containing a variable heavy chain (VH) promoter and a 42 bp fragment of the 1.4 kb hs4 regulatory domain, that included only the overlapping DRE and kappaB motif or mutations of these motifs for transient transfection experiments in CH12.LX and BCL-1 cells. In the CH12.LX cells, TCDD activated the hs4 fragment; however, co-treatment with LPS led to a marked and synergistic activation as previously observed with the wild type 1.4 kb hs4 domain. Mutation of either or both of the DRE and kappaB motifs diminished the effect of TCDD and LPS on the luciferase reporters possessing the 42 bp portion of hs4, and resembled the effect of these treatments on the promoter alone. In the BCL-1 cells, activity of the hs4 fragment was not induced by TCDD and/or LPS treatment. These results suggest that the AhR nuclear complex and NF-kappaB/Rel proteins converge at the DRE and kappaB motif to influence transcriptional activity of the hs4 enhancer fragment. PMID:15212819

Sulentic, Courtney E W; Kang, Jong Soon; Na, Yong Joo; Kaminski, Norbert E

2004-08-01

2

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

PubMed

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

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

2014-10-20

3

Surface-up constructed tandem-inverted bilayer cyclodextrins for enhanced enantioseparation and adsorption.  

PubMed

A new generation of triazole-bridged bilayer cyclodextrins (CDs) chiral stationary phase (CSP) material was constructed via a surface-up 'click' approach. The synergistic effect of the tandem-inverted duplex CDs was evidenced by the superior enantioresolution ability toward selected chiral compounds and the enhanced adsorption ability toward hesperetin. The enantioselectivities of dansyl amino acids and aryl carboxylic acids were promoted by 10-20%, while the resolutions of some aryl carboxylic acids were significantly increased from 0 to 3.5 and beyond. Adsorption experiments of hesperetin reveal that the binding ability of the target bilayer CDCSP is nearly 2.8 times than that of the single layer CDCSP. The current work provides a simple and practical approach to design and synthesize novel functional materials with cooperative CD dimers on surfaces. PMID:24720902

Zhao, Jie; Lu, Xiaohong; Wang, Yong; Tan, Timothy Thatt Yang

2014-05-23

4

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....

5

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

PubMed

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

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

2015-04-01

6

I kappaB alpha physically interacts with a cytoskeleton-associated protein through its signal response domain.  

PubMed Central

The I kappaB alpha protein is a key molecular target involved in the control of NF-kappaB/Rel transcription factors during viral infection or inflammatory reactions. This NF-kappaB-inhibitory factor is regulated by posttranslational phosphorylation and ubiquitination of its amino-terminal signal response domain that targets I kappaB alpha for rapid proteolysis by the 26S proteasome. In an attempt to identify regulators of the I kappaB alpha inhibitory activity, we undertook a yeast two-hybrid genetic screen, using the amino-terminal end of I kappaB alpha as bait, and identified 12 independent interacting clones. Sequence analysis identified some of these cDNA clones as Dlc-1, a sequence encoding a small, 9-kDa human homolog of the outer-arm dynein light-chain protein. In the two-hybrid assay, Dlc-1 also interacted with full-length I kappaB alpha protein but not with N-terminal-deletion-containing versions of I kappaB alpha. I kappaB alpha interacted in vitro with a glutathione S-transferase-Dlc-1 fusion protein, and RelA(p65) did not displace this association, demonstrating that p65 and Dlc-1 contact different protein motifs of I kappaB alpha. Importantly, in HeLa and 293 cells, endogenous and transfected I kappaB alpha coimmunoprecipitated with Myc-tagged or endogenous Dlc-1. Indirect immunofluorescence analyzed by confocal microscopy indicated that Dlc-1 and I kappaB alpha colocalized with both nuclear and cytoplasmic distribution. Furthermore, Dlc-1 and I kappaB alpha were found to associate with the microtubule organizing center, a perinuclear region from which microtubules radiate. Likewise, I kappaB alpha colocalized with alpha-tubulin filaments. Taken together, these results highlight an intriguing interaction between the I kappaB alpha protein and the human homolog of a member of the dynein family of motor proteins and provide a potential link between cytoskeleton dynamics and gene regulation. PMID:9372968

Crépieux, P; Kwon, H; Leclerc, N; Spencer, W; Richard, S; Lin, R; Hiscott, J

1997-01-01

7

Efficient solar water splitting by enhanced charge separation in a bismuth vanadate-silicon tandem photoelectrode  

NASA Astrophysics Data System (ADS)

Metal oxides are generally very stable in aqueous solutions and cheap, but their photochemical activity is usually limited by poor charge carrier separation. Here we show that this problem can be solved by introducing a gradient dopant concentration in the metal oxide film, thereby creating a distributed n+-n homojunction. This concept is demonstrated with a low-cost, spray-deposited and non-porous tungsten-doped bismuth vanadate photoanode in which carrier-separation efficiencies of up to 80% are achieved. By combining this state-of-the-art photoanode with an earth-abundant cobalt phosphate water-oxidation catalyst and a double- or single-junction amorphous Si solar cell in a tandem configuration, stable short-circuit water-splitting photocurrents of ~4 and 3?mA?cm-2, respectively, are achieved under 1 sun illumination. The 4?mA?cm-2 photocurrent corresponds to a solar-to-hydrogen efficiency of 4.9%, which is the highest efficiency yet reported for a stand-alone water-splitting device based on a metal oxide photoanode.

Abdi, Fatwa F.; Han, Lihao; Smets, Arno H. M.; Zeman, Miro; Dam, Bernard; van de Krol, Roel

2013-07-01

8

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

PubMed

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

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

2013-12-01

9

Cytotoxic Enhancement of a Bispecific Diabody by Format Conversion to Tandem Single-chain Variable Fragment (taFv)  

PubMed Central

Diabodies (Dbs) and tandem single-chain variable fragments (taFv) are the most widely used recombinant formats for constructing small bispecific antibodies. However, only a few studies have compared these formats, and none have discussed their binding kinetics and cross-linking ability. We previously reported the usefulness for cancer immunotherapy of a humanized bispecific Db (hEx3-Db) and its single-chain format (hEx3-scDb) that target epidermal growth factor receptor and CD3. Here, we converted hEx3-Db into a taFv format to investigate how format affects the function of a small bispecific antibody; our investigation included a cytotoxicity assay, surface plasmon resonance spectroscopy, thermodynamic analysis, and flow cytometry. The prepared taFv (hEx3-taFv) showed an enhanced cytotoxicity, which may be attributable to a structural superiority to the diabody format in cross-linking target cells but not to differences in the binding affinities of the formats. Comparable cross-linking ability for soluble antigens was observed among hEx3-Db, hEx3-scDb, and hEx3-taFv with surface plasmon resonance spectroscopy. Furthermore, drastic increases in cytotoxicity were found in the dimeric form of hEx3-taFv, especially when the two hEx3-taFv were covalently linked. Our results show that converting the format of small bispecific antibodies can improve their function. In particular, for small bispecific antibodies that target tumor and immune cells, a functional orientation that avoids steric hindrance in cross-linking two target cells may be important in enhancing the growth inhibition effect. PMID:21097496

Asano, Ryutaro; Ikoma, Keiko; Shimomura, Ippei; Taki, Shintaro; Nakanishi, Takeshi; Umetsu, Mitsuo; Kumagai, Izumi

2011-01-01

10

A tandemly repeated thyroglobulin core promoter has potential to enhance efficacy for tissue-specific gene therapy for thyroid carcinomas.  

PubMed

Recombinant adenoviruses, carrying herpes simplex virus thymidine kinase (HSVtk) genes, were developed to evaluate the possibility of tissue-specific gene therapy for thyroid carcinomas. The HSVtk gene was driven by a minimal thyroglobulin (TG) promoter (AdTGtk) and a tandemly repeated minimal TG promoter (Ad2 x TGtk) to obtain thyroid-specific cell killing ability. The transduction of HSVtk genes by infection with Ad2 x TGtk followed by ganciclovir (GCV) treatment showed more powerful cytotoxicity for TG-producing FRTL5 cells, a rat normal thyroid cell line, and FTC-133 cells, a human follicular thyroid carcinoma cell line, than when infected with AdTGtk in vitro. The cell killing ability of Ad2 x TGtk was 10- to 30-fold higher than that of AdTGtk and similar to that of AdCMVtk, which carries HSVtk under the control of CMV promoter. Whereas after treatment with adenovirus/GCV to non-TG-producing cell lines (undifferentiated thyroid carcinoma cell lines and carcinoma cell lines from other tissues), Ad2 x TGtk and AdTGtk needed more than 100-fold concentrated GCV to reach IC(50) compared to AdCMVtk. We confirmed the enhanced efficacy of Ad2 x TGtk for tissue-specific cytotoxicity in vivo. After adenovirus/GCV treatment for FTC-133 tumor-bearing nude mice, Ad2 x TGtk enhanced tumor growth inhibition and survival rates compared to AdTGtk. Tumor growth inhibition and survival rates by Ad2 x TGtk were similar to that by AdCMVtk. Moreover, any toxic effect for rat normal tissues was not revealed after intravenous injections with Ad2 x TGtk and intraperitoneal administrations with GCV in vivo, whereas severe liver damages were observed after treatment with AdCMVtk/GCV. These data indicate a beneficial effect of Ad2 x TGtk for tissue-specific gene therapy for TG-producing thyroid carcinomas without toxicity for normal tissues. PMID:12224028

Takeda, Teiji; Yamazaki, Masanori; Minemura, Kesami; Imai, Yosuke; Inaba, Hidehumi; Suzuki, Satoru; Miyamoto, Takahide; Ichikawa, Kazuo; Kakizawa, Tomoko; Mori, Jun-Ichirou; DeGroot, Leslie J; Hashizume, Kiyoshi

2002-10-01

11

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

PubMed Central

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 matrixes. After development and selection of optimum MRM transitions, 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 on 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 model peptides. The sensitivity improvement observed with the IFT coupled in to the triple quadrupole instrument is based on several unique features. First, ion accumulation 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 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 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 ~4–8. PMID:21344863

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

2011-01-01

12

Bacteria and PAMPs activate nuclear factor kappaB and Gro production in a subset of olfactory ensheathing cells and astrocytes but not in Schwann cells.  

PubMed

The primary olfactory nerves provide uninterrupted conduits for neurotropic pathogens to access the brain from the nasal cavity, yet infection via this route is uncommon. It is conceivable that olfactory ensheathing cells (OECs), which envelope the olfactory nerves along their entire length, provide a degree of immunological protection against such infections. We hypothesized that cultured OECs would be able to mount a biologically significant response to bacteria and pathogen-associated molecular patterns (PAMPs). The response of OECs to Escherichia coli (E. coli) and various PAMPs was compared to that of Schwann cells (SCs), astrocytes (ACs), and microglia (MG). A subset of OECs displayed nuclear localization of nuclear factor kappaB), an inflammatory transcription factor, after treatment with E. coli (20% +/- 5%), lipopolysacchride (33% +/- 9%), and Poly I:C (25% +/- 5%), but not with peptidoglycan or CpG oligonucleotides. ACs displayed a similar level of activation to these treatments, and in addition responded to peptidoglycan. The activation of OECs and ACs was enhanced by coculture with MG (56% +/- 16% and 85% +/- 13%, respectively). In contrast, SCs did not respond to any treatment or to costimulation by MG. Immunostaining for the chemokine Gro demonstrated a functional response that was consistent with NF kappaB activation. OECs expressed mRNA for Toll-like receptors (TLRs) 2 and 4, but only TLR4 protein was detected by Western blotting and immunohistochemistry. The results demonstrate that OECs possess the cellular machinery that permits them to respond to certain bacterial ligands, and may have an innate immune function in protecting the CNS against infection. PMID:17427933

Vincent, Adele J; Choi-Lundberg, Derek L; Harris, Julie A; West, Adrian K; Chuah, Meng Inn

2007-07-01

13

Broadband, polarization-insensitive and wide-angle absorption enhancement of a-Si:H/?c-Si:H tandem solar cells by nanopatterning a-Si:H layer.  

PubMed

A photonic crystal design that significantly enhances the absorption of tandem thin-film solar cells composed by amorphous and microcrystalline silicon (i.e., a-Si:H/?c-Si:H tandem cell) is proposed. The top junction with a-Si:H is nanopatterned as a one-dimensional photonic crystal. Considering the photocurrent matching, we optimally design the junction thickness and the configuration of the nanopattern; moreover, both transverse electric and magnetic incidences with various illuminating angles are taken into account. Calculations by rigorous coupled-wave approach and finite-element method show that the nanophotonic crystal design can improve the absorption and output photocurrent by over 20%, which shows very low sensitivity to the incident polarization. Moreover, the proposed structure is able to sustain the performance for a very wide angle ranges from 0° to ~80°. PMID:24104494

Li, Xiaofeng; Zhang, Cheng; Yang, Zhenhai; Shang, Aixue

2013-07-01

14

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...

15

Enhanced efficiency of single and tandem organic solar cells incorporating a diketopyrrolopyrrole-based low-bandgap polymer by utilizing combined ZnO/polyelectrolyte electron-transport layers.  

PubMed

Power conversion efficiency up to 8.6% is achieved for a solution-processed tandem solar cell based on a diketopyrrolopyrrole-containing polymer as the low-bandgap material after using a thin polyelectrolyte layer to modify the electron-transport ZnO layers, indicating that interfacial engineering is a useful approach to further enhancing the efficiency of tandem organic solar cells. PMID:23847037

Jo, Jang; Pouliot, Jean-Rémi; Wynands, David; Collins, Samuel D; Kim, Jin Young; Nguyen, Thanh Luan; Woo, Han Young; Sun, Yanming; Leclerc, Mario; Heeger, Alan J

2013-09-14

16

Efficiency-enhanced optical parametric down conversion for mid-infrared generation on a tandem periodically poled MgO-doped stoichiometric lithium tantalate chip  

NASA Astrophysics Data System (ADS)

We report an efficiency-enhanced mid-infrared generation via optical parametric down conversion. A tandem periodically-poled MgO-doped stoichiometric lithium tantalate crystal is used to realize on-chip generation and amplification of mid-infrared radiation inside an optical parametric oscillator cavity. We achieved 21.2% conversion efficiency (24% slope efficiency), which is among the highest efficiencies for the pump-to-mid-infrared conversion, with 1064 nm Nd class laser pump. The maximum average output power at 3.87?m reached 635 mW with a 3.0 W pump.

Liu, Y. H.; Xie, Z. D.; Ling, W.; Yuan, Y.; Lv, X. J.; Lu, J.; Hu, X. P.; Zhao, G.; Zhu, S. N.

2011-08-01

17

Efficiency-enhanced optical parametric down conversion for mid-infrared generation on a tandem periodically poled MgO-doped stoichiometric lithium tantalate chip.  

PubMed

We report an efficiency-enhanced mid-infrared generation via optical parametric down conversion. A tandem periodically-poled MgO-doped stoichiometric lithium tantalate crystal is used to realize on-chip generation and amplification of mid-infrared radiation inside an optical parametric oscillator cavity. We achieved 21.2% conversion efficiency (24% slope efficiency), which is among the highest efficiencies for the pump-to-mid-infrared conversion, with 1064 nm Nd class laser pump. The maximum average output power at 3.87 ?m reached 635 mW with a 3.0 W pump. PMID:21935116

Liu, Y H; Xie, Z D; Ling, W; Yuan, Y; Lv, X J; Lu, J; Hu, X P; Zhao, G; Zhu, S N

2011-08-29

18

Efficient enhancement of hydrogen production by Ag/Cu2O/ZnO tandem triple-junction photoelectrochemical cell  

NASA Astrophysics Data System (ADS)

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/Cu2O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu2O/ZnO photoelectrode comparing to that of the Cu2O film. The high performance of the Ag/Cu2O/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.

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

2015-03-01

19

Tandem mass spectrometry and surface enhanced Raman spectroscopy for examining ion-surface and molecule-surface interactions  

Microsoft Academic Search

Interactions of ions and molecules with surfaces were studied in both gas (especially vacuum) and electrochemical environments. In the vacuum environment, a hybrid BEEQ tandem mass spectrometer was used to study hyperthermal ion\\/surface collision processes. The nature of the process at low impact collision energies (typically <10 eV) and the preparation of chemically modified surfaces using such “soft-landing” processes were

Hai Luo

2000-01-01

20

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

PubMed

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

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

2015-01-01

21

Tandem Repeat of a Transcriptional Enhancer Upstream of the Sterol 14alpha Demethylase Gene (CYP51) in Penicillium digitatum  

Microsoft Academic Search

We investigated the mechanism of resistance to demethylation inhibitors (DMI) in Penicillium digitatum by isolating the CYP51 gene, which encodes the target enzyme (P45014DM) of DMI, from three DMI-resistant and three DMI-sensitive strains. The structural genes of all six strains were identical, but in the promoter region, a unique 126-bp sequence was tandemly repeated five times in the DMI-resistant strains

HIROSHI HAMAMOTO; KOJI HASEGAWA; RYOJI NAKAUNE; YOUNG JIN LEE; YOSHIYUKI MAKIZUMI; KATSUMI AKUTSU; TADAAKI HIBI

2000-01-01

22

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

PubMed

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

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

2015-07-01

23

Enhanced separation and characterization of deamidated peptides with RP-ERLIC-based multidimensional chromatography coupled with tandem mass spectrometry.  

PubMed

Deamidation of asparaginyl residues in proteins produces a mixture of asparaginyl, n-aspartyl, and isoaspartyl residues, which affects the proteins' structure, function, and stability. Thus, it is important to identify and quantify the products to evaluate the effects in biological systems. It is still a challenging task to distinguish between the n-Asp and isoAsp deamidation products in a proteome-wide analysis because of their similar physicochemical properties. The quantification of the isomeric deamidated peptides is also rather difficult because of their coelution/poor separation in reverse-phase liquid chromatography (RPLC). We here propose a RP-ERLIC-MS/MS approach for separating and quantifying on a proteome-wide scale the three products related to deamidation of the same peptide. The key to the method is the use of RPLC in the first dimensional separation and ERLIC (electrostatic repulsion-hydrophilic interaction chromatography) in the second, with direct online coupling to tandem MS. The coelution of the three deamidation-related peptides in RPLC is then an asset, as they are collected in the same fraction. They are then separated and identified in the second dimension with ERLIC, which separates peptides on the basis of both pI and GRAVY values. The coelution of the three products in RPLC and their efficient separation in ERLIC were validated using synthetic peptides, and the performance of ERLIC-MS/MS was tested using peptide mixtures from two proteins. Applying this sequence to rat liver tissue, we identified 302 unique N-deamidated peptides, of which 20 were identified via all three deamidation-related products and 70 of which were identified via two of them. PMID:22239700

Hao, Piliang; Qian, Jingru; Dutta, Bamaprasad; Cheow, Esther Sok Hwee; Sim, Kae Hwan; Meng, Wei; Adav, Sunil S; Alpert, Andrew; Sze, Siu Kwan

2012-03-01

24

Targeting receptor-activator of nuclear kappaB ligand in aneurysmal bone cysts: verification of target and therapeutic response.  

PubMed

Aneurysmal bone cyst (ABC) is a benign tumor of bone presenting as a cystic, expansile lesion in both the axial and appendicular skeleton. Axial lesions demand special consideration, because treatment-related morbidity can be devastating. In similar lesions, such as giant cell tumor of bone (GCTB), the receptor-activator of nuclear kappaB ligand (RANKL)-receptor-activator of nuclear kappaB (RANK) signaling axis is essential to tumor progression. Although ABC and GCTB are distinct entities, they both contain abundant multinucleated giant cells and are osteolytic characteristically. We hypothesize that ABCs express both RANKL and RANK similarly in a cell-type specific manner, and that targeted RANKL therapy will mitigate ABC tumor progression. Cellular expression of RANKL and RANK was determined in freshly harvested ABC samples using laser confocal microscopy. A consistent cell-type-specific pattern was observed: fibroblastlike stromal cells expressed RANKL strongly whereas monocyte/macrophage precursor and multinucleated giant cells expressed RANK. Relative RANKL expression was determined by quantitative real-time polymerase chain reaction in ABC and GCTB tissue samples; no difference in relative expression was observed (P > 0.05). In addition, we review the case of a 5-year-old boy with a large, aggressive sacral ABC. After 3 months of targeted RANKL inhibition with denosumab, magnetic resonance imaging demonstrated tumor shrinkage, bone reconstitution, and healing of a pathologic fracture. Ambulation, and bowel and bladder function were restored at 6 months. Denosumab treatment was well tolerated. Post hoc analysis demonstrated strong RANKL expression in the pretreatment tumor sample. These findings demonstrate that RANKL-RANK signal activation is essential to ABC tumor progression. RANKL-targeted therapy may be an effective alternative to surgery in select ABC presentations. PMID:24726460

Pelle, Dominic W; Ringler, Jonathan W; Peacock, Jacqueline D; Kampfschulte, Kevin; Scholten, Donald J; Davis, Mary M; Mitchell, Deanna S; Steensma, Matthew R

2014-08-01

25

Using iTRAQ combined with tandem affinity purification to enhance low-abundance proteins associated with somatically mutated EGFR core complexes in lung cancer.  

PubMed

In this study, we report a novel use for the iTRAQ reagent combined with a peptide mass inclusion list to enhance the signal of low-abundance proteins during analysis by mass spectrometry. C-tagged-SH-EGFR was retrovirally transduced into two mutant lung cancer cell lines (HCC827 and PC9), and the core protein complexes were enriched by tandem affinity purification. Tryptically digested peptides were derivatized with iTRAQ and analyzed by higher-energy collision-induced dissociation mass spectrometry. The data revealed that UBS3B is a member of the EGFR core complex in the HCC827 cell line, which was not apparent by standard, unbiased one-dimensional shotgun analysis and collision-induced dissociation. The expression level of UBS3B, however, was 6-10 times lower than that observed in the PC9 cell line. Thus, using iTRAQ in this fashion allows the identification of low-abundance interactors when combined with samples where the same protein has a higher abundance. Ultimately, this approach may uncover proteins that were previously unknown or only suspected as members of core protein complexes. PMID:20945942

Haura, Eric B; Müller, André; Breitwieser, Florian P; Li, Jiannong; Grebien, Florian; Colinge, Jacques; Bennett, Keiryn L

2011-01-01

26

Analysis of urinary vitamin D? metabolites by liquid chromatography/tandem mass spectrometry with ESI-enhancing and stable isotope-coded derivatization.  

PubMed

The determination of the urinary vitamin D? metabolites might prove helpful in the assessment of the vitamin D status. We developed a method for the determination of trace vitamin D? metabolites, 25-hydroxyvitamin D? [25(OH)D?] and 24,25-dihydroxyvitamin D? [24,25(OH)?D?], in urine using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) combined with derivatization using an ESI-enhancing reagent, 4-(4'-dimethylaminophenyl)-1,2,4-triazoline-3,5-dione (DAPTAD), and its isotope-coded analogue, (2)H4-DAPTAD (d-DAPTAD). The urine samples were treated with ?-glucuronidase, purified with an Oasis hydrophilic-lipophilic balanced (HLB) cartridge, and then subjected to the derivatization. The DAPTAD derivatization enabled the highly sensitive detection (detection limit, 0.25 fmol on the column), and the use of d-DAPTAD significantly improved the assay precision [the intra- (n?=?5) and inter-assay (n?=?3) relative standard deviations did not exceed 9.5%]. The method was successfully applied to urine sample analyses and detected the increases of the urinary 25(OH)D? and 24,25(OH)?D? levels due to vitamin D? administration. PMID:25168117

Ogawa, Shoujiro; Ooki, Satoshi; Shinoda, Kenta; Higashi, Tatsuya

2014-10-01

27

Enantioselective determination of ibuprofen in saliva by liquid chromatography/tandem mass spectrometry with chiral electrospray ionization-enhancing and stable isotope-coded derivatization.  

PubMed

A method was developed and validated for the enantioselective determination of trace ibuprofen (IBU) in saliva using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) combined with the derivatization using a chiral ESI-enhancing reagent, (S)-1-(4-dimethylaminophenylcarbonyl)-3-aminopyrrolidine (DAPAP), and its isotope-coded analog, (2)H4-DAPAP (d-DAPAP). The DAPAP-derivatization enabled the highly sensitive detection [detection limit, 0.15fmol (equivalent to 30fg of intact IBU) on the column] and complete separation (resolution 3.1) of the IBU enantiomers. The use of d-DAPAP significantly improved the assay precision and accuracy; the intra- (n=5) and inter-assay (n=5) relative standard deviations did not exceed 6.2%, and good accuracy (101.3-106.1%) was obtained. The developed method was successfully applied to the quantitative analysis of IBU in saliva. Using this method, salivary concentration-time profiles of each enantiomer after a single oral administration of the racemic IBU to healthy subjects were obtained. The area under the salivary concentration-time curve of the (S)-enantiomer was ca. twice that of the (R)-enantiomer due to the unidirectional chiral inversion of the (R)- to (S)-enantiomer in vivo. Thus, saliva-based noninvasive pharmacokinetic analyses of IBU enantiomers were achieved by this method. PMID:24999866

Ogawa, Shoujiro; Tadokoro, Hiroaki; Sato, Maho; Higashi, Tatsuya

2014-09-01

28

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

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

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

29

An enhanced throughput method for quantification of sulfur mustard adducts to human serum albumin via isotope dilution tandem mass spectrometry.  

PubMed

Here, we report an enhanced throughput method for the diagnosis of human exposure to sulfur mustard. A hydroxyethylthioethyl (HETE) ester-adducted tripeptide, produced by pronase digestion of human serum albumin, was selected as the quantitative exposure biomarker. Cibacron Blue enrichment was developed from an established cartridge method into a 96-well plate format, increasing throughput and ruggedness. This new method decreased sample volume 2.5-fold. Addition of a precipitation and solid-phase extraction concentration step increased the sensitivity of the method. With the conversion to a 96-well plate and optimization of chromatography, the method resulted in a 3-fold decrease in analysis time. Inclusion of a confirmation ion has increased specificity. The method was found to be linear between 0.050 and 50 µM sulfur mustard exposure with a precision for both quality control samples of ?6.5% relative standard deviation and an accuracy of >96%. The limit of detection (3So) was calculated to be ?0.0048 µM, an exposure value similar to that of the HETE-albumin adduct method first described by Noort and co-workers (Noort et al., 1999; Noort el al., 2004) which used protein precipitation to isolate albumin. A convenience set of 124 plasma samples from healthy unexposed individuals was analyzed using this method to assess background levels of exposure to sulfur mustard; no positive results were detected. PMID:24201816

Andacht, Tracy M; Pantazides, Brooke G; Crow, Brian S; Fidder, Alex; Noort, Daan; Thomas, Jerry D; Blake, Thomas A; Johnson, Rudolph C

2014-01-01

30

A Y-short tandem repeat specific DNA enhancement strategy to aid the analysis of late reported (? 6 days) sexual assault cases.  

PubMed

The ability to obtain an autosomal short tandem repeat (STR) profile of the semen donor from the reproductive tract of a living victim rapidly diminishes as the post-coital interval increases. This is of concern where victims of sexual assault provide vaginal samples several days after the incident. In order to overcome the technological impediments inherent in autosomal DNA typing with extended interval samples, we previously employed the use of Y chromosome STR profiling which, by targeting only male DNA, can eliminate masking of the male profile (by the victim's alleles) or critical polymerase chain reaction reagent titration (due to excessive female DNA). Thus employing Y-STR profiling and additional enhancement strategies, we reported the ability to recover Y-STR profiles from samples collected 5 to 6 days after intercourse. However, the reproductive biology literature indicates that spermatozoa are found in the human cervix up to 7 to 10 days post coitus. Thus, even with improved extraction and profiling techniques, we failed to routinely recover profiles from samples collected ? 6 days after intercourse. The aim of the present work was to develop additional strategies to permit the recovery of male donor DNA profiles from ? 6 post-coital samples. Using nested polymerase chain reaction and DNA concentration procedures that together maximize the recovery and targeting of male DNA, we demonstrate the ability to obtain semen donor Y-STR profiles in extended interval post-coital samples collected 6 to 9 days after intercourse. This approaches the recognized time limits of sperm residence in the cervico-vaginal canal as described in the clinical literature. PMID:24526669

Hanson, Ek; Ballantyne, J

2014-10-01

31

Liquid chromatography/tandem mass spectrometry sensitivity enhancement via online sample dilution and trapping: applications in microdosing and dried blood spot (DBS) bioanalysis.  

PubMed

A simple online sample dilution, enrichment, and cleanup technique was developed for sensitive microdosing and dried blood spot (DBS) liquid chromatography/tandem mass spectrometric (LC/MS/MS) bioanalysis. Samples are diluted online with water and enriched in a trap column which is subsequently switched inline with the analytical column. Excellent lansoprazole (in acetonitrile) peak shape is maintained even with an 80-microL injection. In comparison, similar chromatographic peaks were observed only when a small volume of the same solution, i.e., 1 microL, was injected on a regular high-performance liquid chromatography (HPLC) system, where an injection of 5 microL resulted in severe peak fronting. A substantial enhancement in sensitivity is realized in the trapping mode using large injection volumes. The trap column is washed at the beginning and at the end of each injection with aqueous and organic solvent respectively to remove matrix components. This ultimately leads to reduction of matrix effects and mass spectrometer noise, thus facilitating the utilization of protein precipitation as the sample preparation for plasma samples. A lower limit of quantitation (LLOQ) of 0.5 pg/mL was demonstrated for lansoprazole in human plasma with a signal-to-noise (S/N) ratio of 13 using a 100 microL injection. Excellent intra-day precision and accuracy were established for lansoprazole in human plasma with good linearity (R(2) > 0.999) from 0.5 to 500 pg/mL. This level of LLOQ makes LC/MS/MS a practical alternative for microdosing bioanalysis, where the dose is typically 100 times lower than the therapeutic dose. The same technique was applied to quantitate lansoprazole in human whole blood employing DBS technology. With a single 3-mm punch, i.e. approximately 2 microL of whole blood or approximately 1 microL plasma, a LLOQ of 0.1 ng/mL showed sufficient S/N ratio (40) for lansoprazole when 75 microL of extract was injected. In all, the online sample dilution, cleanup, and enrichment technique demonstrated the practical utility of LC/MS/MS in microdosing and DBS bioanalysis. PMID:20740533

Li, Fumin; Zulkoski, John P; Ding, Jie; Brown, Wes; Addison, Tom

2010-09-15

32

Thermal-barrier production and indentification in a tandem mirror  

SciTech Connect

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.

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

33

Thyrotropin modifies activation of nuclear factor kappaB by tumour necrosis factor alpha in rat thyroid cell line.  

PubMed Central

We have recently demonstrated that nuclear factor kappaB (NF-kappaB) mediates the tumour necrosis factor alpha (TNF-alpha)-dependent expression of the gene encoding interleukin 6 (IL-6) in rat thyroid FRTL-5 cells cultured in the presence of thyrotropin (TSH). In the present study we investigated how TSH is involved in the activation of NF-kappaB by TNF-alpha in the cells. Electrophoretic mobility-shift assay revealed that, in the absence of TSH, TNF-alpha activated a single protein-DNA complex containing the p50 subunit but not other NF-kappaB subunits such as p65. In contrast, two distinct protein-DNA complexes were activated in the presence of TSH: the faster-migrating complex contained only p50 subunit; the slower-migrating complex consisted of p65-p50 heterodimer. This TSH effect was mimicked by forskolin and thyroid-stimulating antibodies obtained from patients with Graves's disease, suggesting that an increase in intracellular cAMP is responsible for the induction of different NF-kappaBs by TNF-alpha. A transient transfection study with a luciferase reporter gene driven by multimerized NF-kappaB sites demonstrated that TNF-alpha increased the luciferase activities only in the presence of TSH, and that this increase was inhibited by the co-transfection of mutant p65, which prevented the function of wild-type p65 in a dominant-negative manner. Accordingly, TNF-alpha activated the expression of the IL-6 gene in the presence of TSH but not in its absence. Although the expression of the p105 gene, another known target for NF-kappaB, was increased by TNF-alpha in the absence of TSH, the presence of TSH further increased the mRNA level. Taken together, these observations indicate that the presence of TSH is crucial for the NF-kappaB-mediated actions of TNF-alpha on thyroid follicular cells. PMID:11237861

Kikumori, T; Kambe, F; Nagaya, T; Funahashi, H; Seo, H

2001-01-01

34

Tandem Pairing in Heavy-Fermion Superconductors  

NASA Astrophysics Data System (ADS)

We consider the internal structure of a d-wave heavy-fermion superconducting condensate, showing that it necessarily contains two components condensed in tandem: pairs of quasiparticles on neighboring sites and composite pairs consisting of two electrons bound to a single local moment. These two components draw upon the antiferromagnetic and Kondo interactions to cooperatively enhance the superconducting transition temperature. This tandem condensate is electrostatically active, with an electric quadrupole moment predicted to lead to a superconducting shift in the nuclear quadrupole resonance frequency.

Flint, Rebecca; Coleman, Piers

2010-12-01

35

Tandem mobile robot system  

DOEpatents

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.

Buttz, James H. (Albuquerque, NM); Shirey, David L. (Albuquerque, NM); Hayward, David R. (Albuquerque, NM)

2003-01-01

36

Tandem mirror fusion research  

SciTech Connect

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.

Baldwin, D.E.

1983-12-02

37

Vitamin E as an Antiosteoporotic Agent via Receptor Activator of Nuclear Factor Kappa-B Ligand Signaling Disruption: Current Evidence and Other Potential Research Areas  

PubMed Central

Osteoporosis is a growing healthcare burden that affects the quality of life in the aging population. Vitamin E is a potential prophylactic agent that can impede the progression of osteoporosis. Various in vivo studies demonstrated the antiosteoporotic potential of vitamin E, but evidence on its molecular mechanism of action is limited. A few in vitro studies showed that various forms of vitamin E can affect the receptor activator of nuclear factor kappa-B ligand (RANKL) signaling and their molecular targets, thus preventing the formation of osteoclasts in the early stage of osteoclastogenesis. Various studies have also shown that the effects of the different isoforms of vitamin E differ. The effects of single isoforms and combinations of isoforms on bone metabolism are also different. Vitamin E may affect bone metabolism by disruption of free radical-mediated RANKL signaling, by its oestrogen-like effects, by its effects on the molecular mechanism of bone formation, by the anti-inflammatory effects of its long-chain metabolites on bone cells, and by the inhibition of 3-hydroxyl-3-methyglutaryl coenzyme A (HMG-CoA). In conclusion, the vitamin E isoforms have enormous potential to be used as prophylactic and therapeutic agents in preventing osteoporosis, but further studies should be conducted to elucidate their mechanisms of action. PMID:22919420

Chin, Kok-Yong; Ima-Nirwana, Soelaiman

2012-01-01

38

Tandem resonator reflectance modulator  

DOEpatents

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. 8 figs.

Fritz, I.J.; Wendt, J.R.

1994-09-06

39

Tandem resonator reflectance modulator  

DOEpatents

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.

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

1994-01-01

40

Current results of the tandem mirror experiment  

SciTech Connect

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.

Drake, R.P.

1980-04-09

41

Stereoselective tandem cascade furan cycloadditions.  

PubMed

Oligofurans linked by a rigid tether undergo tandem cycloaddition reactions with high stereoselectivity. The reaction of bisfurans with dimethyl acetylenedicarboxylate (DMAD) involves tandem [4 + 2]/[4 + 2] cycloadditions in a pincer mode. The reaction of oligofurans with arynes involves stereoselective tandem [4 + 2]/[4 + 2] cycloaddition reactions in a domino mode. The corresponding aryne adducts have been transformed into extended perylene derivatives by deoxygenation and aromatization with HCl/EtOH. PMID:24228899

Criado, Alejandro; Vilas-Varela, Manuel; Cobas, Agustín; Pérez, Dolores; Peña, Diego; Guitián, Enrique

2013-12-20

42

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

SciTech Connect

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.

Ishijima, Muneaki [Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 3-10, Kanda-Surugadai 2-Chome, Chiyoda-Ku, Tokyo 101-0062 (Japan); Ezura, Yoichi [Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 3-10, Kanda-Surugadai 2-Chome, Chiyoda-Ku, Tokyo 101-0062 (Japan) and Department of Molecular Biology, Institute of Gerontology, Nippon Medical School, Kawasaki (Japan)]. E-mail: ezura.mph@mril.tmd.ac.jp; Tsuji, Kunikazu [Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 3-10, Kanda-Surugadai 2-Chome, Chiyoda-Ku, Tokyo 101-0062 (Japan)] (and others)

2006-10-01

43

Negative tandem mirror  

SciTech Connect

A tandem mirror configuration can be created by combining hot electron end cell plasmas with neutral beam pumping. A region of large negative potential formed in each end cell confines electrons in the central cell. The requirement of charge neutrality causes the central cell potential to become negative with respect to ground in order to confine ions as well as electrons. We discuss the method of producing and calculating the desired axial potential profile, and show the calculated axial potential profile and plasma parameters for a negative configuration of TMX-Upgrade.

Poulsen, P.; Allen, S.L.; Casper, T.A.; Grubb, D.P.; Jong, R.A.; Nexsen, W.E.; Porter, G.D.; Simonen, T.C.

1981-11-30

44

Monolithic tandem solar cell  

DOEpatents

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.

Wanlass, M.W.

1994-06-21

45

Solution-processed parallel tandem polymer solar cells using silver nanowires as intermediate electrode.  

PubMed

Tandem architecture is the most relevant concept to overcome the efficiency limit of single-junction photovoltaic solar cells. Series-connected tandem polymer solar cells (PSCs) have advanced rapidly during the past decade. In contrast, the development of parallel-connected tandem cells is lagging far behind due to the big challenge in establishing an efficient interlayer with high transparency and high in-plane conductivity. Here, we report all-solution fabrication of parallel tandem PSCs using silver nanowires as intermediate charge collecting electrode. Through a rational interface design, a robust interlayer is established, enabling the efficient extraction and transport of electrons from subcells. The resulting parallel tandem cells exhibit high fill factors of ?60% and enhanced current densities which are identical to the sum of the current densities of the subcells. These results suggest that solution-processed parallel tandem configuration provides an alternative avenue toward high performance photovoltaic devices. PMID:25405589

Guo, Fei; Kubis, Peter; Li, Ning; Przybilla, Thomas; Matt, Gebhard; Stubhan, Tobias; Ameri, Tayebeh; Butz, Benjamin; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

2014-12-23

46

Pharmacological benefit of I(1)-imidazoline receptors activation and nuclear factor kappa-B (NF-?B) modulation in experimental Huntington's disease.  

PubMed

Huntington's disease (HD), a neurodegenerative disorder, is characterized by progressive motor dysfunction, emotional disturbances, dementia, weight loss and anxiety. The tremendous amount of research work is required to identify new pharmacological agents of therapeutic utility to combat this condition. This study investigates the effect of selective modulator of I1-imidazoline receptor (moxonidine) as well as nuclear factor kappa-B (NF-?B) (natrium diethyl dithio carbamate trihydrate-NDDCT) on 3-nitropropionic acid (3-NPA) induced experimental HD condition. 3-NPA was used to induce mitochondrial damage and associated HD symptoms in rats. Anxiety was assessed using Elevated plus maze-EPM and learning-memory was assessed using EPM and Morris water maze-MWM. Different biochemical estimations were used to assess brain striatum oxidative stress (lipid peroxide, superoxide dismutase and catalase), nitric oxide levels (nitrite/nitrate), cholinergic activity (brain striatum acetyl cholinesterase activity), and mitochondrial enzyme complex (I, II and IV) activities. 3-NPA has induced anxiety, impaired learning-memory with a reduction in body weight, locomotor activity, grip strength. It has increased brain striatum acetylcholinesterase-AChE activity, oxidative stress (lipid peroxide, nitrite/nitrate, superoxide dismutase and catalase) and impaired mitochondrial complex enzyme (I, II and IV) activities. Tetrabenazine-TBZ (monoamine storage inhibitor) was used as positive control. Treatment with moxonidine, NDDCT and TBZ significantly attenuated 3-NPA induced reduction in body weight, locomotor activity, grip strength, anxiety as well as impaired learning and memory. Administration of these agents attenuated 3-NPA induced various biochemical impairments. Therefore, modulation of I1-imidazoline receptor as well as NF-?B may be considered as potential pharmacological agents for the management of 3-NPA induced HD. PMID:24582883

Gupta, Surbhi; Sharma, Bhupesh

2014-03-01

47

Enhanced Nicotine Metabolism in HIV-1–Positive Smokers Compared with HIV-Negative Smokers: Simultaneous Determination of Nicotine and its Four Metabolites in Their Plasma Using a Simple and Sensitive Electrospray Ionization Liquid Chromatography–Tandem Mass Spectrometry Technique  

PubMed Central

Smoking is approximately three times more prevalent in HIV-1–positive than HIV-negative individuals in the United States. Nicotine, which is the major constituent of tobacco, is rapidly metabolized mainly by cytochrome P450 (CYP2A6) to many metabolites. In this study, we developed a simple, fast, and sensitive electrospray ionization liquid chromatography–tandem mass spectrometry method using a strong cation solid phase extraction, and determined the concentration of nicotine and its four major metabolites (cotinine, nornicotine, norcotinine, and trans-3?-hydroxycotinine) in the plasma of HIV-1–positive and HIV-negative smokers. The multiple reaction monitoring transitions for nicotine, cotinine, trans-3?-hydroxycotinine, nornicotine, norcotinine, nicotine-d4, and cotinine-d3 were selected at mass-to-charge ratios of 163.3/117.1, 177.5/80.3, 193.2/80.1, 149.5/132.3, 163.4/80.3, 167.3/121.4, and 180.3/101.2, respectively. The lower limit of quantitation for nicotine and its metabolites was 0.53 ng/ml, which is relatively more sensitive than those previously reported. The concentration of nicotine was detected 5-fold lower in HIV-1–positive smokers (7.17 ± 3.8 ng/ml) than that observed in HIV-negative smokers (33.29 ± 15.4 ng/ml), whereas the concentration of the metabolite nornicotine was 3-fold higher in HIV-1–positive smokers (6.8 ± 2.9 ng/ml) than in HIV-negative smokers (2.3 ± 1.2 ng/ml). Although it was statistically nonsignificant, the concentration of the metabolite cotinine was also higher in HIV-1–positive smokers (85.6 ± 60.5 ng/ml) than in HIV-negative smokers (74.9 ± 40.5 ng/ml). In conclusion, a decrease in the concentration of nicotine and an increase in the concentration of its metabolites in HIV-1–positive smokers compared with HIV-negative smokers support the hypothesis that nicotine metabolism is enhanced in HIV-1–positive smokers compared with HIV-negative smokers. PMID:24301609

Earla, Ravinder; Ande, Anusha; McArthur, Carole; Kumar, Anil

2014-01-01

48

Enzyme catalysed tandem reactions.  

PubMed

To transfer to the laboratory, the excellent efficiency shown by enzymes in Nature, biocatalysis, had to mimic several synthetic strategies used by the living organisms. Biosynthetic pathways are examples of tandem catalysis and may be assimilated in the biocatalysis field for the use of isolated multi-enzyme systems in the homogeneous phase. The concurrent action of several enzymes that work sequentially presents extraordinary advantages from the synthetic point of view, since it permits a reversible process to become irreversible, to shift the equilibrium reaction in such a way that enantiopure compounds can be obtained from prochiral or racemic substrates, reduce or eliminate problems due to product inhibition or prevent the shortage of substrates by dilution or degradation in the bulk media, etc. In this review we want to illustrate the developments of recent studies involving in vitro multi-enzyme reactions for the synthesis of different classes of organic compounds. PMID:23490810

Oroz-Guinea, Isabel; García-Junceda, Eduardo

2013-04-01

49

Tandem Cylinder Noise Predictions  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

50

A nanocomposite interconnecting layer for tandem small molecular organic photovoltaic cells  

NASA Astrophysics Data System (ADS)

A nanocomposite interconnecting layer of C60:LiF/Ag/MoOx had been applied in the tandem structure of organic photovoltaic cells to achieve high short circuit current (Jsc) and power conversion efficiency (PCE). The Jsc had been enhanced 40% after applying the nanocomposite interconnecting layer into a tandem structure compared to the conventional interconnecting layer of Bathocuproine (BCP)/Ag/MoOx. The improvement is due to the enhancement of the light absorption of the devices. A tandem device PCE of 3.04% was achieved by further improving the light absorption in the individual subcell units in the tandem structure by means of a bi-functional buffer layer of C60:LiF/BCP.

Luo, D. Y.; Yu, L. M.; Man, J. X.; Liu, Z.; Lu, Z. H.

2014-03-01

51

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

PubMed Central

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

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

2014-01-01

52

Flow through cascades in tandem  

NASA Technical Reports Server (NTRS)

An exact treatment of the problem of finding the incompressible, inviscid two-dimensional flow around two cascades in tandem is presented. The analysis includes solutions of both the direct and the inverse problems. These problems are solved by conformally mapping the tandem cascade onto the region between two concentric circles in which region there are suitably placed flow singularities. Formulas for the velocity and the potential in the annular region are presented in a closed form by means of elliptic functions. The equations are presented in a form suitable for computation.

Spraglin, William E

1951-01-01

53

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

PubMed

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

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

2015-03-01

54

Tandem motors reduce well costs  

Microsoft Academic Search

The new generation of tandem mud motors that recently appeared on the drilling scene is significantly affecting drilling efficiency worldwide. These motors provide drillers with increased horsepower at the bit, higher torque, and faster rates of penetration (ROP). With advanced engineering and more durable materials, motor life is being extended, thereby increasing the time between bit trips and reducing drilling

M. Hooper; C. Daigle; R. Crowe

1995-01-01

55

Tandem Mass Spectrometry in Physiology  

NSDL National Science Digital Library

Tandem mass spectrometry coupled to liquid chromatography (LC-MS/MS) allows identification of proteins in a complex mixture without need for protein purification ("shotgun" proteomics). Recent progress in LC-MS/MS-based quantification, phosphoproteomic analysis, and targeted LC-MS/MS using multiple reaction monitoring (MRM) has made LC-MS/MS a powerful tool for the study of cell physiology.

2007-12-01

56

Tandemly repeated trinucleotides — comparative analysis  

Microsoft Academic Search

Characteristics of 64 possible tandem trinucleotide repeats (TSSR) from Homo sapiens (hs), Mus musculus (mm) and Rattus norvegicus (rn) genomes are presented. Comparative analysis of TSSR frequency depending on their repetitiveness and similarity of the TSSR length distributions is shown. Comparative analysis of TSSR sequence motifs and association between type of motif and its length (n) using ?-coefficient method (quantitatively

Monika Piwowar; Jan Meus; Piotr Piwowar; Justyna Stefaniak; Irena Roterman

2006-01-01

57

Hybrid tandem photovoltaic devices with a transparent conductive interconnecting recombination layer  

SciTech Connect

Highlights: ? This work enhanced power conversion efficiency of the hybrid tandem solar cell from 1.0% to 2.6%. ? The interfacial series resistance of the tandem solar cell was eliminated by inserting ITO layer. ? This work shows the feasibility of the highly efficient hybrid tandem solar cells. -- Abstract: We demonstrate hybrid tandem photovoltaic devices with a transparent conductive interconnecting recombination layer. The series-connected hybrid tandem photovoltaic devices were developed by combining hydrogenated amorphous silicon (a-Si:H) and polymer-based organic photovoltaics (OPVs). In order to enhance the interfacial connection between the subcells, we employed highly transparent and conductive indium tin oxide (ITO) thin layer. By using the ITO interconnecting layer, the power conversion efficiency of the hybrid tandem solar cell was enhanced from 1.0% (V{sub OC} = 1.041 V, J{sub SC} = 2.97 mA/cm{sup 2}, FF = 32.3%) to 2.6% (V{sub OC} = 1.336 V, J{sub SC} = 4.65 mA/cm{sup 2}, FF = 41.98%) due to the eliminated interfacial series resistance.

Kim, Taehee; Choi, Jin Young; Jeon, Jun Hong; Kim, Youn-Su; Kim, Bong-Soo; Lee, Doh-Kwon; Kim, Honggon; Han, Seunghee [Solar Cell Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 136-791 (Korea, Republic of)] [Solar Cell Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 136-791 (Korea, Republic of); Kim, Kyungkon, E-mail: kimkk@ewha.ac.kr [Solar Cell Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 136-791 (Korea, Republic of) [Solar Cell Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 136-791 (Korea, Republic of); Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

2012-10-15

58

Asymmetric tandem organic solar cells  

NASA Astrophysics Data System (ADS)

Organic photovoltaics (OPVs) is an area that has attracted much attention recently as a potential low cost, sustainable source of energy with a good potential for full-scale commercialisation. Understanding the factors that determine the efficiency of such cells is therefore a high priority, as well as developing ways to boost efficiency to commercially-useful levels. In addition to an intensive search for new materials, significant effort has been spent on ways to squeeze more performance out of existing materials, such as multijunction cells. This thesis investigates double junction tandem cells in the context of small molecule organic materials. . Two different organic electron donor materials, boron subphthalocyanine chloride (SubPc) and aluminium phthalocyanine chloride (ClAlPc) were used as donors in heterojunctions with C60 to create tandem cells for this thesis. These materials have been previously used for solar cells and the absorption spectra of the donor materials complement each other, making them good candidates for tandem cell architectures. The design of the recombination layer between the cells is considered first, with silver nanoparticles demonstrated to work well as recombination centres for charges from the front and back sub-cells, necessary to avoid a charge build-up at the interface. The growth conditions for the nanoparticles are optimised, with the tandem cells outperforming the single heterojunction architecture. Optical modelling is considered as a method to improve the understanding of thin film solar cells, where interference effects from the reflective aluminium electrode are important in determining the magnitude of absorption a cell can achieve. The use of such modelling is first demonstrated in hybrid solar cells based on a SubPc donor with a titanium oxide (TiOx) acceptor; this system is ideal for observing the effects of interference as only the SubPc layer has significant absorption. The modelling is then applied to tandem cells where it is used to predict the short-circuit current (Jsc) generation of the sub-cells, which is not accessible experimentally. Current-matching is then used to predict the Jsc of the complete tandem device. . As a support to the optical modelling, ellipsometry measurements of thin films of ClAlPc are presented. These films of known thickness are analysed to extract the complex refractive index for use in optical modelling calculations. A dependence of the complex refractive index on film thickness and substrate is also noted. Finally, the external quantum efficiency (EQE) technique is considered as applied to solar cells, and an additional method is proposed to characterise current balancing in asymmetric tandem cells under illumination. This technique is verified experimentally by two separate sets of data..

Howells, Thomas J.

59

Tandem motors increase well bore penetration rate  

SciTech Connect

Running a positive displacement downhole motor with tandem power sections and the proper bit significantly increases the rate of penetration and reduces stalling problems. The use of positive displacement mud motors (PDMs) with two power sections has improved penetration rates on a number of drilling applications in western Canada. The majority of all the tandem motor runs to date have been successful. Results of these tandem runs show that tandem motors should be considered in any situation where a single motor is run. This paper reviews the performance of tandem motors at several case sites. It describes the design, rate of penetration, bit selection, mud systems, and use in horizontal wells.

Matthews, S. [Halliburton Drilling Systems, Calgary, Alberta (Canada); McCosh, R. [CenAlta Well Services Inc., Calgary, Alberta (Canada)

1996-02-26

60

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

SciTech Connect

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.

Fourspring PM

2007-03-19

61

Nanocrystal assembly for tandem catalysis  

DOEpatents

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.

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

2014-10-14

62

Tandem motors reduce well costs  

SciTech Connect

The new generation of tandem mud motors that recently appeared on the drilling scene is significantly affecting drilling efficiency worldwide. These motors provide drillers with increased horsepower at the bit, higher torque, and faster rates of penetration (ROP). With advanced engineering and more durable materials, motor life is being extended, thereby increasing the time between bit trips and reducing drilling costs. This article reviews the performance, design, and operation of these motors.

Hooper, M.; Daigle, C. [Halliburton Energy Services, Houston, TX (United States); Crowe, R. [Halliburton Energy Services, Aberdeen (United Kingdom)

1995-10-01

63

Tandem compressors in gas storage  

Microsoft Academic Search

To demonstrate that a single gas-turbine compressor set can be an attractive economic alternative to multiunit reciprocating compressors for use in typical gas-storage injection and withdrawal cycles, Cooper Rolls Inc. and Union Gas Ltd., Canada, installed a unique tandem-driven centrifugal compressor rated at 19,690 kW at the Dawn compressor station in south Ontario. Preliminary operating data indicate that the actual

D. W. Wood; R. G. Reid

1979-01-01

64

Rotational stability of tandem mirrors  

Microsoft Academic Search

The general stability equation for low-m rotational-ballooning instabilities in axisymmetric mirror geometry is derived for an isotropic pressure plasma, including a boundary term which represents the stabilizing effect of an unspecified anchor. The corresponding variational principle, together with a particular quadrupole anchor model, is used to compute the low-..beta.. rotational-interchange marginal stability condition for a conventional tandem mirror. The stability

J. P. Freidberg; D. A. D'Ippolito

1983-01-01

65

Rotational stability of tandem mirrors  

Microsoft Academic Search

The general stability equation for low-m rotational-ballooning instabilities in axisymmetric mirror geometry is derived for an isotropic pressure plasma, including a boundary term which represents the stabilizing effect of an unspecified anchor. The corresponding variational principle, together with a particular quadrupole anchor model, is used to compute the low-? rotational-interchange marginal stability condition for a conventional tandem mirror. The stability

J. P. Freidberg; D. A. D’Ippolito

1983-01-01

66

"Nanocrystal bilayer for tandem catalysis"  

SciTech Connect

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

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

67

Advances in tandem reactions with organozinc reagents.  

PubMed

The design and implementation of tandem reactions provides organic chemists with numerous challenges, in particular that of undesired cross-reactivity between substrates. Among organometallics, the use of organozinc reagents in tandem reactions provides several advantages as a result of their broad functional group tolerance and compatibility with transition metals. This review highlights prominent examples of recent advances in tandem reactions with organozinc reagents that illustrate their potential in organic synthesis. PMID:25708795

Kim, Ju Hyun; Ko, Young Ok; Bouffard, Jean; Lee, Sang-Gi

2015-04-10

68

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.

69

Recent Activities at Tokai Tandem Accelerator  

NASA Astrophysics Data System (ADS)

Recent activities at the JAEA-Tokai tandem accelerator facility are presented. The terminal voltage of the tandem accelerator reached 19.1 MV by replacing acceleration tubes. The multi-charged positive-ion injector was installed in the terminal of the tandem accelerator, supplying high-current noble-gas ions. A superconducting cavity for low-velocity ions was developed. Radioactive nuclear beams of 8,9Li and fission products, produced by the tandem accelerator and separated by the ISOL, were supplied with experiment. Recent results of nuclear physics experiments are reported.

Ishii, Tetsuro

2010-05-01

70

The characterization of tandem and corrugated wings  

NASA Astrophysics Data System (ADS)

Dragonfly wings have two distinct features: a tandem configuration and wing corrugation. Both features have been extensively studied with the aim to understand the superior flight performance of dragonflies. In this paper we review recent development of tandem and corrugated wing aerodynamics. With regards to the tandem configuration, this review will focus on wing/wing and wing/vortex interactions at different flapping modes and wing spacing. In addition, the aerodynamics of tandem wings under gusty conditions will be reviewed and compared with isolated wings to demonstrate the gust resistance characteristics of flapping wings. Regarding corrugated wings, we review their structural and aerodynamic characteristics.

Lian, Yongsheng; Broering, Timothy; Hord, Kyle; Prater, Russell

2014-02-01

71

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

Code of Federal Regulations, 2013 CFR

...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the...

2013-10-01

72

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

Code of Federal Regulations, 2012 CFR

...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the...

2012-10-01

73

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

Code of Federal Regulations, 2014 CFR

...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the...

2014-10-01

74

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

Code of Federal Regulations, 2011 CFR

...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the proportion...circuits used in the tandem to end office links (or a surrogate based on the...

2011-10-01

75

14 CFR 23.302 - Canard or tandem wing configurations.  

Code of Federal Regulations, 2013 CFR

... false Canard or tandem wing configurations. 23.302...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward...structure of a canard or tandem wing configuration must:...

2013-01-01

76

14 CFR 23.302 - Canard or tandem wing configurations.  

Code of Federal Regulations, 2012 CFR

... false Canard or tandem wing configurations. 23.302...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward...structure of a canard or tandem wing configuration must:...

2012-01-01

77

14 CFR 23.302 - Canard or tandem wing configurations.  

Code of Federal Regulations, 2011 CFR

... false Canard or tandem wing configurations. 23.302...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward...structure of a canard or tandem wing configuration must:...

2011-01-01

78

14 CFR 23.302 - Canard or tandem wing configurations.  

Code of Federal Regulations, 2010 CFR

... false Canard or tandem wing configurations. 23.302...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward...structure of a canard or tandem wing configuration must:...

2010-01-01

79

14 CFR 23.302 - Canard or tandem wing configurations.  

Code of Federal Regulations, 2014 CFR

... false Canard or tandem wing configurations. 23.302...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing configurations. The forward...structure of a canard or tandem wing configuration must:...

2014-01-01

80

Tandem mirror technology demonstration facility  

SciTech Connect

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.

Not Available

1983-10-01

81

Improved monolithic tandem solar cell  

SciTech Connect

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.

Wanlass, M.W.

1991-04-23

82

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

SciTech Connect

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.

Li, Guijun, E-mail: gliad@connect.ust.hk; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing [State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2014-06-09

83

Photoelectrochemistry of coreshell tandem junction np+  

E-print Network

for water splitting, an integrated solar fuels device requires catalysts connected to the light absorbers S. Lewis*ab Tandem junction (n­p+ -Si/ITO/WO3/liquid) core­shell microwire devices for solar (anode: tandem device, cathode: Pt disc). The solar energy-conversion efficiencies were very low, 0

Atwater, Harry

84

Tandem motors increase well bore penetration rate  

Microsoft Academic Search

Running a positive displacement downhole motor with tandem power sections and the proper bit significantly increases the rate of penetration and reduces stalling problems. The use of positive displacement mud motors (PDMs) with two power sections has improved penetration rates on a number of drilling applications in western Canada. The majority of all the tandem motor runs to date have

S. Matthews; R. McCosh

1996-01-01

85

Argonne Tandem-Linac Accelerator System  

SciTech Connect

Design considerations and operational experience for the existing heavy-ion accelerator consisting of a tandem injecting into a superconducting linac are summarized, with emphasis on the general features of the system. This introduction provides the basis for a discussion of the objectives and design of ATLAS, a larger tandem-linac system being formed by expanding the existing superconducting linac.

Bollinger, L.M.

1983-01-01

86

Survey of plant short tandem DNA repeats  

Microsoft Academic Search

Length variations in simple sequence tandem repeats are being given increased attention in plant genetics. Some short tandem repeats (STRs) from a few plant species, mainly those at the dinucleotide level, have been demonstrated to show polymorphisms and Mendelian inheritance. In the study reported here a search for all of the possible STRs ranging from mononucleotide up to tetranucleotide repeats

Z. Wang; J. L. Weber; G. Zhong; S. D. Tanksley

1994-01-01

87

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

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.

Hirai, Fumihiko [First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807-8555 (Japan); Nakayamada, Shingo [First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807-8555 (Japan); Okada, Yosuke [First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807-8555 (Japan); Saito, Kazuyoshi [First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807-8555 (Japan); Kurose, Hitoshi [Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Mogami, Akira [Pharmaceuticals Research Unit Research and Development Division Mitsubishi Pharma Corporation, Kamoshida-cho, Aoba-ku, Yokohama 227-0033 (Japan); Tanaka, Yoshiya [First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807-8555 (Japan)]. E-mail: tanaka@med.uoeh-u.ac.jp

2007-04-27

88

Optimizing a tandem disk model  

NASA Astrophysics Data System (ADS)

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.

Healey, J. V.

1983-08-01

89

Potent Activation of the Human Tandem Pore Domain K Channel TRESK with Clinical Concentrations of Volatile Anesthetics  

Microsoft Academic Search

The tandem pore domain K channel family mediates backgroundKcurrentspresentinexcitablecells.Currents passed by certain members of the family are enhanced by volatile anesthetics, thus suggesting a novel mechanism of anesthesia. The newest member of the family, termed TRESK (TWIK (tandem pore domain weak inward recti- fying channel)-related spinal cord K channel), has not been studied for anesthetic sensitivity. We isolated the coding

Canhui Liu; John D. Au; Hilary Liao Zou; Joseph F. Cotten; C. Spencer Yost

2004-01-01

90

Radiometric cross-calibration of the Landsat7 ETM+ and Landsat5 TM sensors based on tandem data sets  

Microsoft Academic Search

Early in its mission, the Landsat-7 spacecraft was temporarily placed in a “tandem” orbit very close to that of the Landsat-5 spacecraft in order to facilitate the establishment of sensor calibration continuity between the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-5 Thematic Mapper (TM) sensors. The key period for the tandem configuration was June 1–4, 1999, during which hundreds

P. m. Teillet; J. l. Barker; B. l. Markham; R. R Irish; G. Fedosejevs; J. c. Storey

2001-01-01

91

Tandem mechanisms facilitate dehydration of crude  

SciTech Connect

In tandem, electrostatic and mechanical coalescence mechanisms can dehydrate oil at higher loading rates and/or lower temperatures than either mechanism acting alone. One of the most effective methods for removing entrained (emulsified) water from crude oil involves the use of high-voltage electric fields. Under the influence of an electric field, water droplets dispersed in the oil become polarized (i.e., acquire a net charge). Attractive electrostatic forces between droplets which have acquired opposite charges promote coalescence and, therefore, more rapid gravitation of the aqueous phase from the mixture. The mechanisms of electrostatically enhanced coalescence have been reviewed elsewhere. Both ac and dc electric fields are commonly used in oil field coalescers and a comparison of the relative merits of these two systems and a discussion of the effects of electrode configuration on coalescence are available in the literature. In a high-voltage electric field, water droplets in oil are subjected to hydrodynamic and electrical stresses which can lead to droplet dispersal in competition with electrostatically induced coalescence. These stresses become more severe and are more likely to cause dispersal with increasing droplet diameter and increasing electric field strength. Therefore, electrical and hydrodynamic stresses tend to limit the maximum size of droplets which can exist in the field.

Sublette, K.L.; Johnson, B.

1986-05-19

92

Software dependability in the Tandem GUARDIAN system  

NASA Technical Reports Server (NTRS)

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.

Lee, Inhwan; Iyer, Ravishankar K.

1995-01-01

93

Tandem mass spectrometry: analysis of complex mixtures  

SciTech Connect

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.

Singleton, K.E.

1985-01-01

94

In situ detection of tandem DNA repeat length  

Microsoft Academic Search

A simple method for scoring short tandem DNA repeats is presented. An oligonucleotide target, containing tandem repeats embedded in a unique sequence, was hybridized to a set of complementary probes, containing tandem repeats of known lengths. Single-stranded loop structures formed on duplexes containing a mismatched (different) number of tandem repeats. No loop structure formed on duplexes containing a matched (identical)

Ron Yaar; Przemyslaw Szafranski; Charles R. Cantor; Cassandra L. Smith

1996-01-01

95

Zoledronate inhibits receptor activator of nuclear factor kappa-B ligand-induced osteoclast differentiation via suppression of expression of nuclear factor of activated T-cell c1 and carbonic anhydrase 2.  

PubMed

Bisphosphonates (BPs) are widely used in the prevention of skeletal-related events (SRE), including osteoporosis, skeletal metastases of malignant tumours, and multiple myeloma. Osteonecrosis of the jaw (ONJ) is frequently reported as a major adverse effect induced by BP treatment. The receptor activator of the nuclear factor kappa-B ligand (RANKL) inhibitor, denosumab, has recently been used to prevent SRE, but the frequency of ONJ induced by denosumab is similar to that by BPs. This finding suggests that the inhibition of RANKL-mediated osteoclastogenesis may have a close relationship with the occurrence of ONJ. We therefore investigated the expression status of RANKL-inducible genes in zoledronate-treated mouse osteoclast precursor cells. The molecular targets of zoledronate in the RANKL signal pathway and additional factors associated with osteoclastogenesis were analysed by genome-wide screening. Microarray analysis identified that among 31 genes on 44 entities of RANKL-inducible genes, the mRNA expression level of two genes, i.e., nuclear factor of activated T-cells c1 (NFATc1) and carbonic anhydrase 2 (CAII), was decreased in zoledronate-treated cells. Subsequent analyses verified that these two genes were significantly silenced by zoledronate treatment and that their expression was restored following inhibition of zoledronate action by geranylgeraniol. Zoledronate inhibited RANKL-induced osteoclast differentiation by suppression of NFATc1 and CAII gene expression. Our results suggest that these genes might be common targets for zoledronate and denosumab in the mechanism underlying RANKL-induced osteoclast differentiation. A clear understanding of the common molecular mechanisms of bone-remodelling agents is thus essential for prevention of ONJ. PMID:25601046

Nakagawa, Takayuki; Ohta, Kouji; Kubozono, Kazumi; Ishida, Yoko; Naruse, Takako; Takechi, Masaaki; Kamata, Nobuyuki

2015-04-01

96

New tandem accelerator facility of Tokyo University  

NASA Astrophysics Data System (ADS)

An old tandem accelerator is being replaced by a new one at the University of Tokyo. The new facility consists of a vertical 5 MV Pelletron with two ion sources and dedicated beam lines for fine analytical studies.

Koichi, Kobayashi; Satoshi, Hatori; Chuichiro, Nakano

1993-06-01

97

On decision making in tandem networks  

E-print Network

We study the convergence of Bayesian learning in a tandem social network. Each agent receives a noisy signal about the underlying state of the world, and observes her predecessor's action before choosing her own. We ...

Dia, Manal

2009-01-01

98

Dynamically doped white light emitting tandem devices.  

PubMed

Solution-processed, salt-containing, blue and orange light-emitting layers lead to efficient white light-emitting devices when arranged in a tandem configuration separated by a thin metal layer. PMID:24167058

Akatsuka, Takeo; Roldán-Carmona, Cristina; Ortí, Enrique; Bolink, Henk J

2014-02-01

99

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)

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.

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

2015-03-01

100

Enhanced Interferon Signaling Pathway in Oral Cancer Revealed by Quantitative Proteome Analysis of Microdissected Specimens Using 16O/18O Labeling and Integrated Two-dimensional LC-ESI-MALDI Tandem MS*  

PubMed Central

Oral squamous cell carcinoma (OSCC) remains one of the most common cancers worldwide, and the mortality rate of this disease has increased in recent years. No molecular markers are available to assist with the early detection and therapeutic evaluation of OSCC; thus, identification of differentially expressed proteins may assist with the detection of potential disease markers and shed light on the molecular mechanisms of OSCC pathogenesis. We performed a multidimensional 16O/18O proteomics analysis using an integrated ESI-ion trap and MALDI-TOF/TOF MS system and a computational data analysis pipeline to identify proteins that are differentially expressed in microdissected OSCC tumor cells relative to adjacent non-tumor epithelia. We identified 1233 unique proteins in microdissected oral squamous epithelia obtained from three pairs of OSCC specimens with a false discovery rate of <3%. Among these, 977 proteins were quantified between tumor and non-tumor cells. Our data revealed 80 dysregulated proteins (53 up-regulated and 27 down-regulated) when a 2.5-fold change was used as the threshold. Immunohistochemical staining and Western blot analyses were performed to confirm the overexpression of 12 up-regulated proteins in OSCC tissues. When the biological roles of 80 differentially expressed proteins were assessed via MetaCore™ analysis, the interferon (IFN) signaling pathway emerged as one of the most significantly altered pathways in OSCC. As many as 20% (10 of 53) of the up-regulated proteins belonged to the IFN-stimulated gene (ISG) family, including ubiquitin cross-reactive protein (UCRP)/ISG15. Using head-and-neck cancer tissue microarrays, we determined that UCRP is overexpressed in the majority of cheek and tongue cancers and in several cases of larynx cancer. In addition, we found that IFN-? stimulates UCRP expression in oral cancer cells and enhances their motility in vitro. Our findings shed new light on OSCC pathogenesis and provide a basis for the future development of novel biomarkers. PMID:19297561

Chi, Lang-Ming; Lee, Chien-Wei; Chang, Kai-Ping; Hao, Sheng-Po; Lee, Hang-Mao; Liang, Ying; Hsueh, Chuen; Yu, Chia-Jung; Lee, I-Neng; Chang, Yin-Ju; Lee, Shih-Ying; Yeh, Yuan-Ming; Chang, Yu-Sun; Chien, Kun-Yi; Yu, Jau-Song

2009-01-01

101

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

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

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

2014-10-17

102

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

Code of Federal Regulations, 2010 CFR

...Distance shall be measured as airline distance between the serving...distance shall be measured as airline distance between the tandem...Distance shall be measured as airline distance between the tandem...carrier that is subject to price cap regulation as that...

2010-10-01

103

Comparison of Discrimination Methods for Peptide Classification in Tandem Mass Spectrometry  

E-print Network

Comparison of Discrimination Methods for Peptide Classification in Tandem Mass Spectrometry Anthony versus diseased tissue. Tandem mass spectrometry(MS/MS) of peptides is a central technology, Bioinformatics, Tandem mass spectrometry, Peptide classifica- tion. I. INTRODUCTION TANDEM Mass Spectrometry (MS

104

The Joy of Learning Enhancing Learning Experience -Improving Learning Quality  

E-print Network

involve developing the #12;eTandem Language Learning Integrated in the Curriculum: Reflection fromThe Joy of Learning Enhancing Learning Experience - Improving Learning Quality Proceedings-963-89559-3-7 eTANDEM LANGUAGE LEARNING INTEGRATED IN THE CURRICULUM: REFLECTION FROM STUDENTS'PERSPECTIVES Jue

Halazonetis, Thanos

105

Oxygen-evoked changes in transcriptional activity of the 5'-flanking region of the human amiloride-sensitive sodium channel (alphaENaC) gene: role of nuclear factor kappaB.  

PubMed Central

Expression of the alpha-subunit of the amiloride-sensitive sodium channel (alphaENaC) is regulated by a number of factors in the lung, including oxygen partial pressure (PO2). As transcriptional activation is a mechanism for raising cellular mRNA levels, we investigated the effect of physiological changes in PO2 on the activity of the redox-sensitive transcription factor nuclear factor kappaB (NF-kappaB) and transcriptional activity of 5'-flanking regions of the human alphaENaC gene using luciferase reporter-gene vectors transiently transfected into human adult alveolar carcinoma A549 cells. By Western blotting we confirmed the presence of NF-kappaB p65 but not p50 in these cells. Transiently increasing PO2 from 23 to 42 mmHg for 24 h evoked a significant increase in NF-kappaB DNA-binding activity and transactivation of a NF-kappaB-driven luciferase construct (pGLNF-kappaBpro), which was blocked by the NF-kappaB activation inhibitor sulphasalazine (5 mM). Transcriptional activity of alphaENaC-luciferase constructs containing 5'-flanking sequences (including the NF-kappaB consensus) were increased by raising PO2 from 23 to 142 mmHg if they contained transcriptional initiation sites (TIS) for exons 1A and 1B (pGL3E2.2) or the 3' TIS of exon 1B alone (pGL3E0.8). Sulphasalazine had no significant effect on the activity of these constructs, suggesting that the PO2-evoked rise in activity was not a direct consequence of NF-kappaB activation. Conversely, the relative luciferase activity of a construct that lacked the 3' TIS, a 3' intron and splice site but still retained the 5' TIS and NF-kappaB consensus sequence was suppressed significantly by raising PO2. This effect was reversed by sulphasalazine, suggesting that activation of NF-kappaB mediated PO2-evoked suppression of transcription from the exon 1A TIS of alphaENaC. PMID:12023897

Baines, Deborah L; Janes, Mandy; Newman, David J; Best, Oliver G

2002-01-01

106

Recent ``tandem puff-on-wire`` experiments on ACE-4  

SciTech Connect

The tandem-puff configuration is a variant on a plasma opening switch z-pinch, driven by a microsecond timescale Marx bank. Current flows in an annular-plasma column for about a microsecond and is then commutated to a central, annular-gas puff. The gas puff subsequently implodes near maximum generator current. Previously reported tandem puff experiments were configured with a single, co-axial, 25--50 micron diameter copper wire on the pinch axis. The data showed enhanced yield in the soft x-ray energy range of {approximately}1 keV which included significant Cu L-shell thermal emission. This paper will present recent results using neon gas injected by a fast valve and 11-centimeter diameter annular nozzle, imploded onto one or more central aluminum wires using load currents of over 2 megamps and implosion times in the range of 300--400 nanoseconds. The radiated spectrum is predominantly thermal K-shell radiation from both atomic species. The authors will attempt to characterize the energy transfer mechanisms relative to existing data.

Coleman, P.L.; Rauch, J.; Rix, W.; Thompson, J. [Maxwell Labs., San Diego, CA (United States); Wessel, F.J. [Univ. of California, Irvine, CA (United States). Dept. of Physics

1996-12-31

107

Structural basis for tandem L27 domain-mediated polymerization  

SciTech Connect

The establishment of epithelial cell polarity requires the assembly of multiprotein complexes and is crucial during epithelial morphogenesis. Three scaffolding proteins, Dlg1, MPP7, and Mals3, can be assembled to form a complex that functions in the establishment and maintenance of apicobasal polarity in epithelial tissues through their L27 domains. Here we report the crystal structure of a 4-L27-domain complex derived from the human tripartite complex Dlg1-MPP7-Mals3 in combination with paramagnetic relaxation enhancement measurements. The heterotrimer consists of 2 pairs of heterodimeric L27 domains. These 2 dimers are asymmetric due to the large difference between the N- and C-terminal tandem L27 domain of MPP7. Structural analysis combined with biochemical experiments further reveals that the loop {alpha}A-{alpha}B and helix {alpha}B of the C-terminal L27 domain of MPP7 play a critical role in assembling the entire tripartite complex, suggesting a synergistic tandem L27-mediated assembling event.

Yang, Xue; Xie, Xingqiao; Chen, Liu; Zhou, Hao; Wang, Zheng; Zhao, Weijing; Tian, Ran; Zhang, Rongguang; Tian, Changlin; Long, Jiafu; Shen, Yuequan (UST - China); (Nankai); (Chinese Aca. Sci.)

2010-12-01

108

Tandem-mirror program: status and projection  

SciTech Connect

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.

Van Atta, C.M.

1981-03-12

109

Recovering Sparse Low-rank Blocks in Tandem Mass Spectrometry  

E-print Network

Recovering Sparse Low-rank Blocks in Tandem Mass Spectrometry Christoph Studer1, Graeme Pope2 samples observed using tandem mass spectrometery (TMS). To efficiently perform SLoB-based peptide fragments [5]­ [8] and then, to identify these peptides using tandem mass spectrometery (TMS). In this paper

110

Ruthenium-Catalyzed Concurrent Tandem Reactions University of North Carolina  

E-print Network

Ruthenium-Catalyzed Concurrent Tandem Reactions Greg Boyce University of North Carolina February 8. Enyne Cascades I. Dienyne Metathesis II. Ring Rearrangement Metathesis III. Metathesis/Non-Metathesis I of Tandem Reactions ­ Sequential tandem reactions involve coupling transformations that operate

Johnson, Jeff S.

111

Design and Test of Transonic Compressor Rotor with Tandem Cascade  

Microsoft Academic Search

The stage pressure ratio in axial flow compressors and fans can be considerably increased by using suitable tandem cascades. In the tandem cascade, the gap flow from the clearance between the front and the rear blades makes it possible to control the separation induced by shock. Therefore, the tandem cascade can obtain larger turning and higher pressure ratio without the

Yusuke SAKAI; Akinori MATSUOKA; Shinya SUGA; Keisuke HASHIMOTO

2003-01-01

112

Tandem repeats finder: a program to analyze DNA sequences  

Microsoft Academic Search

A tandem repeat in DNA is two or more contiguous, approximate copies of a pattern of nucleotides. Tandem repeats have been shown to cause human disease, may play a variety of regulatory and evolutionary roles and are important laboratory and analytic tools. Extensive knowledge about pattern size, copy number, mutational history, etc. for tandem repeats has been limited by the

Gary Benson

1999-01-01

113

A Survey On Algorithmic Aspects Of Tandem Repeats Evolution  

Microsoft Academic Search

Local repetitions in genomes are called tandem repeats. A tandem repeat contains multiple, but slightly dieren t copies of a repeated unit. It changes over time as the copies are altered by mutations, when additional copies are created by amplic ation of an existing copy, or when a copy is removed by contraction. Theses changes let tandem repeats evolve dynamically.

Eric Rivals

2004-01-01

114

25 MV tandem accelerator at Oak Ridge  

SciTech Connect

A new heavy-ion accelerator facility is under construction at the Oak Ridge National Laboratory. A brief description of the scope and status of this project is presented with emphasis on the first operational experience with the 25 MV tandem accelerator.

Jones, C.M.

1980-01-01

115

Modelling of tandem cell temperature coefficients  

SciTech Connect

This paper discusses the temperature dependence of the basic solar-cell operating parameters for a GaInP/GaAs series-connected two-terminal tandem cell. The effects of series resistance and of different incident solar spectra are also discussed.

Friedman, D.J. [National Renewable Energy Lab., Golden, CO (United States)

1996-05-01

116

Tandem mirror fusion-fission hybrid studies  

SciTech Connect

Initial tandem mirror hybrid studies predict the ability to produce large amounts of fissile fuel (2 to 7 tons U233 per year from a 4000 MW plant) at a cost that adds less than 25% to the cost of power from a LWR.

Lee, J.D.

1980-04-24

117

Tandem mirror fusion fission hybrid studies  

SciTech Connect

Initial Tandem Mirror Hybrid Study predicts the ability to produce large amounts of fissile fuel (2 to 7 tonnes per year U233 from a 4000 MW plant) at a cost that adds less than 25% to the cost of power from an LWR.

Lee, J.D

1980-02-15

118

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

SciTech Connect

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.

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

2005-01-01

119

Measurements of the hot-electron density during thermal-barrier operation in a tandem mirror experiment  

SciTech Connect

Thermal-barrier operation of a tandem mirror requires the generation of a dense population of energetic, mirror-trapped electrons. This has been confirmed by experimental results from the initial thermal-barrier experiments in the Tandem Mirror Experiment-Upgrade (Phys. Rev. Lett. 53, 783 (1984)). For discharges with similar operating conditions, a dramatic enhancement of the axial confinement time was observed only when the mirror-confined hot-electron density was a large fraction of the total electron density at the position of the thermal barrier. These results are in excellent agreement with theoretical predictions.

James, R.A.; Ellis, R.F.; Lasnier, C.J.; Grubb, D.P.; Casper, T.A.

1986-08-01

120

Dye Sensitized Tandem Photovoltaic Cells  

SciTech Connect

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.

Barber, Greg D.

2009-12-21

121

The LLNL multi-user tandem laboratory  

NASA Astrophysics Data System (ADS)

An FN tandem laboratory, cofunded 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 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.

Davis, J. C.

1989-04-01

122

LLNL multi-user tandem laboratory  

NASA Astrophysics Data System (ADS)

The Physics Department at Lawrence Livermore National Laboratory (LLNL) is building a new tandem Van de Graaff laboratory for nuclear physics and applied physics and technology programs. The laboratory has been funded by a coalition of users including several LLNL divisions, Sandia National Laboratories Livermore, and the University of California. The tandem is the former University of Washington injector FN. The accelerator is upgraded with a Pelletron charging system, Dowlish spiral inclined field beam tubes and SF 6 insulation. The laboratory incorporates several novel design concepts. Initial operation will be in June, 1987 with full operation in October, 1987. Design features, radiological controls, computer assisted operation, and experimental facilities of the laboratory are discussed.

Proctor, I. D.; Davis, J. C.; Eaton, M. R.; Garibaldi, J. L.; Moore, T. L.; Schumacher, B. J.; Southon, J. R.; Zimmerman, T. A.

1988-05-01

123

Tandem microwave waste remediation and decontamination system  

DOEpatents

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.

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

1999-01-01

124

How tandem power motors improve drilling performance  

Microsoft Academic Search

Tandem power section positive displacement mud-motors (TPS-PDMs) can increase penetration rate when used with tricone and PDC bits. This is achieved by increasing the available output torque and shaft rotational speed by reducing pressure drop per stage in the power section. Early PDMs were single-lobe 1:2 rotor-stator ratio motors. Horsepower produced by these PDMs was a result of high output-shaft

B. Califf; M. Johnson

1994-01-01

125

Current and lattice matched tandem solar cell  

DOEpatents

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.

Olson, Jerry M. (Lakewood, CO)

1987-01-01

126

TandEM: Titan and Enceladus mission  

Microsoft Academic Search

TandEM was proposed as an L-class (large) mission in response to ESA’s Cosmic Vision 2015–2025 Call, and accepted for further\\u000a studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds\\u000a tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini–Huygens\\u000a mission. These

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

2009-01-01

127

ICRF fuelling of tandem mirror end plugs  

Microsoft Academic Search

Generation of waves at the ion cyclotron frequency and its harmonics may be useful for fuelling as well as heating the high-energy and high-density mirror end plugs required by a tandem mirror. Fuelling may be accomplished by trapping the ions that are ejected from the central-cell electrostatic well as they flow out through the end plugs. It is shown that

J. Kesner

1979-01-01

128

Tandem mirror next step: remote maintenance  

SciTech Connect

This study of the next proposed experiment in the Mirror Fusion Program, the Tandem Mirror Next Step (TMNS), has included serious consideration of the maintenance requirements of such a large source of high energy neutrons with its attendant throughput of tritium. Although maintenance will be costly in time and money, our conclusion is that with careful attention to a design for maintenance plan such a device can be reliably operated.

Doggett, J.N.; Damm, C.C.; Hanson, C.L.

1980-10-27

129

DDES and IDDES of tandem cylinders.  

SciTech Connect

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.

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

130

TandEM: Titan and Enceladus mission  

USGS Publications Warehouse

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.

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

131

21 CFR 862.1055 - Newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...  

Code of Federal Regulations, 2010 CFR

...and acylcarnitines using tandem mass spectrometry. 862.1055 Section 862...acylcarnitines using tandem mass spectrometry. (a) Identification ...acylcarnitines using tandem mass spectrometry is a device that...

2010-04-01

132

Tandem repeating modular proteins avoid aggregation in single molecule force spectroscopy experiments.  

PubMed

We have used single molecule force spectroscopy to explore the unfolding and refolding behavior of the immunoglobulin-like I27 protein in aqueous 2,2,2-trifluoroethanol (TFE). In bulk solution experiments, a 28% v/v TFE solution has previously been observed to enhance intermolecular attractions and lead to misfolding and aggregation of tandem modular proteins of high sequence identity. In our single molecule experiments, however, we measure successful refolding of the polyprotein I27(8) in all TFE solutions up to 35% v/v. Using a single molecule micromanipulation technique, we have shown that refolding of a polyprotein with identical repeats is not hindered by the presence of this cosolvent. These experimental results provide new insight into the properties of tandem repeating proteins and raise interesting questions as to the evolutionary success of such proteins in avoiding misfolding and aggregation. PMID:18020430

Dougan, Lorna; Fernandez, Julio M

2007-12-13

133

47 CFR 36.124 - Tandem switching equipment-Category 2.  

Code of Federal Regulations, 2010 CFR

... false Tandem switching equipment-Category 2. 36.124 Section 36.124 Telecommunication...124 Tandem switching equipment—Category 2. (a) Tandem switching...included with Local Switching Equipment—Category 3. (1) At toll center...

2010-10-01

134

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

SciTech Connect

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.

Hayward, David R. (Albuquerque, NM); Buttz, James H. (Albuquerque, NM); Shirey, David L. (Albuquerque, NM)

2002-01-01

135

Tandem Dyes: Stability in cocktails and compensation considerations.  

PubMed

Background: The stability and performance of tandem conjugated antibodies can be impaired when stored in antisera cocktails (1,2). This, and the need for frequent re-compensation due to the possible spectral spill over variation between tandem lots, reduces the robustness of clinical flow cytometry panels that include tandems. Since tandems are required for standard 8-10 colour screens, further studies of the stability of tandems in cocktails and their spill over variability are warranted. Methods: The performance of PE- and APC-tandems stored in cocktails was tested on fresh bone marrow, preserved blood and lyophilised cell samples over 1-, 6- or 8-week periods respectively, and their spill over matrices were compared. The observed correction factor differences were used as the basis for analysing how the application of an incorrect compensation matrix could influence data interpretation. Results: Signal intensities and background fluorescence remained constant for all fluorochromes in the cocktails tested. Spill over correction factors for different PE-Cy7 mAbs did not exceed or were only marginally higher than those for non-tandem organic dye conjugated mAb. By applying the correction factor differences observed between tandem mAb lots to clinical data, it was found that the over and under compensation would not alter the clinical interpretation. Conclusions: Tandems can be safely stored and used in cocktails. However, each cocktail should be tested on relevant material prior to use. Exact compensation settings are a requirement for accurate data. Provided that careful evaluation of tandem compensation requirements is carried out, certain tandems may use a generic compensation matrix. © 2013 Clinical Cytometry Society. PMID:24347239

Johansson, Ulrika; Macey, Marion

2013-12-17

136

A Hybrid Approach To Tandem Cylinder Noise  

NASA Technical Reports Server (NTRS)

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.

Lockard, David P.

2004-01-01

137

The Naples University 3 MV tandem accelerator  

SciTech Connect

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.

Campajola, L.; Brondi, A. [Dipartimento di Scienze Fisiche, Universita di Napoli ''Federico II'' Complesso Universitario di Monte S.Angelo via Cintia 80126 Napoli, Italy and Istituto Nazionale di Fisica Nucleare, Sez. di Napoli (Italy)

2013-07-18

138

The Naples University 3 MV tandem accelerator  

NASA Astrophysics Data System (ADS)

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.

Campajola, L.; Brondi, A.

2013-07-01

139

Detection of Recombination in Variable Number Tandem Repeat Sequences  

Microsoft Academic Search

Tandem repeats are repeated sequences whose copies are adjacent along the chromosomes. They account for large portion of eukaryotic genomes and are found in all types of living organisms. Among tandem repeats, those with repeat unit of middle size are called minisatellites. These loci depart from classical loci beca use of the propensity to vary in size due to the

Ezekiel Adebiyi; Eric Rivals

2007-01-01

140

Peptide Retention Time Prediction Yields Improved Tandem Mass Spectrum Identification  

E-print Network

%, 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 chro- matography (LC), mass spectometry (MS), tandem mass spectrometry (MS/MS), support vector

Noble, William Stafford

141

The Shaft Torque of a Tandem Axial-Piston Pump  

E-print Network

The Shaft Torque of a Tandem Axial- Piston Pump Noah D. Manring Viral S. Mehta Mechanical of this study is to identify the best indexed position of two rotating groups within a tandem axial-piston pump rotating group within an axial piston machine. From this analysis, an equation is pro- duced that describes

Manring, Noah D.

142

Experimental Protein Mixture for Validating Tandem Mass Spectral Analysis  

Microsoft Academic Search

Several methods have been used to identify peptides that correspond to tandem mass spec- tra. In this work, we describe a data set of low energy tandem mass spectra generated from a control mixture of known protein components that can be used to evaluate the accuracy of these methods. As an example, these spectra were searched by the SEQUEST application

Andrew Keller; Samuel Purvine; Alexey I. Nesvizhskii; Sergey Stolyar; David R. Goodlett; Eugene Kolker

2002-01-01

143

Idler-resonant femtosecond tandem optical parametric oscillator  

E-print Network

Idler-resonant femtosecond tandem optical parametric oscillator tuning from 2.1 m to 4.2 m Karl A-resonant femtosecond tandem optical parametric oscillator is reported that is based on periodically poled lithium). The configuration uses two cascaded gratings arranged so that the nonresonant signal from the first grating acts

144

Highly Loaded Fan by Using Tandem Cascade Rotor Blade  

Microsoft Academic Search

For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could

Hiroaki Hasegawa; Shinya Suga; Akinori Matsuoka

2003-01-01

145

Tandem Clusters of Membrane Proteins in Complete Genome Sequences  

E-print Network

of genes coding for membrane proteins was investigated in 16 complete genomes: 4 archaea, 11 bacteria of isolated ATP-binding protein components in the ABC transporters. Possible implications of tandem clusterTandem Clusters of Membrane Proteins in Complete Genome Sequences Daisuke Kihara1 and Minoru

Kihara, Daisuke

146

ERROR VISUALIZATION FOR TANDEM ACOUSTIC MODELING ON THE AURORA TASK  

E-print Network

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

Ellis, Dan

147

High-sensitivity mass spectrometry with a tandem accelerator  

SciTech Connect

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.

Henning, W.

1983-01-01

148

Vacuum insulation tandem accelerator for B. Bayanov1  

E-print Network

273 Vacuum insulation tandem accelerator for NCT B. Bayanov1 , Yu. Belchenko1 , V. Belov1 , G of high current hydrogen negative ions by special geometry of potential electrodes with vacuum insulation. Fig. 1 shows the construction of vacuum insulation tandem accelerator developed at BINP, as a base

Taskaev, Sergey Yur'evich

149

A tandem-based compact dual-energy gamma generator  

SciTech Connect

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.

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

150

Identification of GABAC Receptor Protein Homeostasis Network Components from Three Tandem Mass Spectrometry Proteomics Approaches  

PubMed Central

Gamma-amino butyric acid type C (GABAC) receptors inhibit neuronal firing primarily in retina. Maintenance of GABAC receptor protein homeostasis in cells is essential for its function. However, a systematic study of GABAC receptor protein homeostasis (proteostasis) network components is absent. Here, co-immunoprecipitation of human GABAC-?1 receptor complexes was performed in HEK293 cells overexpressing ?1 receptors. To enhance the coverage and reliability of identified proteins, immunoisolated ?1 receptor complexes were subjected to three tandem mass spectrometry (MS)-based proteomic analyses: namely, gel-based tandem MS (GeLC-MS/MS), solution-based tandem MS (SoLC-MS/MS), and multidimensional protein identification technology (MudPIT). From the 107 identified proteins, we assembled GABAC-?1 receptor proteostasis network components, including proteins with protein folding, degradation, and trafficking functions. We studied representative individual ?1 receptor interacting proteins, including calnexin, a lectin chaperone that facilitates glycoprotein folding, and LMAN1, a glycoprotein trafficking receptor, and global effectors that regulate protein folding in cells based on bioinformatics analysis, including HSF1, a master regulator of the heat shock response, and XBP1, a key transcription factor of the unfolded protein response. Manipulating selected GABAC receptor proteostasis network components is a promising strategy to regulate GABAC receptor folding, trafficking, degradation and thus function to ameliorate related retinal diseases. PMID:24079818

Wang, Ya-Juan; Han, Dong-Yun; Tabib, Tracy; Yates, John R.; Mu, Ting-Wei

2013-01-01

151

Bayesian Design of Tandem Networks for Distributed Detection With Multi-Bit Sensor Decisions  

NASA Astrophysics Data System (ADS)

We consider the problem of decentralized hypothesis testing under communication constraints in a topology where several peripheral nodes are arranged in tandem. Each node receives an observation and transmits a message to its successor, and the last node then decides which hypothesis is true. We assume that the observations at different nodes are, conditioned on the true hypothesis, independent and the channel between any two successive nodes is considered error-free but rate-constrained. We propose a cyclic numerical design algorithm for the design of nodes using a person-by-person methodology with the minimum expected error probability as a design criterion, where the number of communicated messages is not necessarily equal to the number of hypotheses. The number of peripheral nodes in the proposed method is in principle arbitrary and the information rate constraints are satisfied by quantizing the input of each node. The performance of the proposed method for different information rate constraints, in a binary hypothesis test, is compared to the optimum rate-one solution due to Swaszek and a method proposed by Cover, and it is shown numerically that increasing the channel rate can significantly enhance the performance of the tandem network. Simulation results for $M$-ary hypothesis tests also show that by increasing the channel rates the performance of the tandem network significantly improves.

Tarighati, Alla; Jalden, Joakim

2015-04-01

152

Progress in the tandem mirror program  

SciTech Connect

Experimental results in TMX have confirmed the basic principles of the tandem-mirror concept. A center-cell particle confinement parameter eta tau approx. 10/sup 11/ cm/sup -3/ s has been obtained at ion temperatures around 100 eV, which is a hundred-fold improvement over single mirrors at the same temperatures. For TMX these results have been obtained at peak beta values in the center cell in the range 10 to 40%, not yet limited by MHD activity; and ion-cyclotron resonant heating (ICRH) in the Phaedrus tandem-mirror experiment has produced beta values approx. 25%, which is several times the ideal MHD limit for that device. In addition, it has been demonstrated that the end fan chambers of TMX simultaneously isolate the hot electrons from the end walls, provide adequate pumping and conveniently dispose of the exhaust plasma energy either by thermal deposition on the end wall or by direct conversion to electricity (at 48% efficiency in agreement with calculations). Also, evidence was obtained for inherent divertor action in TMX, presumably in part responsible for the observed low impurity level (<0.5% low-Z ions in the center cell).

Fowler, T.K.; Borchers, R.R.

1981-09-13

153

Theoretical studies in tandem mirror physics  

SciTech Connect

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.

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

154

Electronic Tandem Language Learning (eTandem): A Third Approach to Second Language Learning for the 21st Century  

ERIC Educational Resources Information Center

Tandem language learning occurs when two learners of different native languages work together to help each other learn the other language. First used in face-to-face contexts, Tandem is now increasingly being used by language-learning partners located in different countries who are linked via various forms of electronic communication, a context…

Cziko, Gary A.

2004-01-01

155

Poiseuille flow-induced vibrations of two cylinders in tandem  

NASA Astrophysics Data System (ADS)

Laminar flows past two tandem cylinders which are free to move transversely in a parallel-wall channel were studied numerically by the lattice Boltzmann method. With fixed Reynolds number Re=100, blockage ratio ?=1/4 and structural damping ?=0, the effect of streamwise separation between two cylinders at a range of S/D=[1.1, 10] on the motions of cylinders and fluids was studied for both mass ratios of m(*)=1 and m(*)=0.1. A variety of distinct vibration regimes involving periodic, quasi-periodic and non-periodic vibrations with corresponding flow patterns were observed. A detailed analysis of the vibration amplitudes, vibration frequencies and relative equilibrium positions for both mass ratios demonstrated that as S/D increases, the interaction of the two cylinders first enhances and then reduces. In the strong coupling regime, both cylinders oscillate periodically around the centerline of the channel with large vibration amplitudes and high vibration frequencies. By comparing with the case of an isolated cylinder, a further study indicated that the gap flow plays an important role in such a dynamic system, and the vortex cores formation behind the front cylinder causes the interaction of the cylinders decouple rapidly. Based on the present observations, such a dynamic model system can be considered as a novel type of vortex-induced vibrations (VIV) and is expected to find applications in fluid mixing and heat transfer.

Lin, Jianzhong; Jiang, Renjie; Chen, Zhongli; Ku, Xiaoke

2013-07-01

156

Initial results of the Tandem Mirror Experiment (TMX) at the Lawrence Livermore Laboratory  

SciTech Connect

Initial experimental results from the Tandem Mirror Experiment (TMX) are presented. Axial profiles of the plasma density and potential necessary for electrostatically enhanced confinement of the central-cell ions have been generated and sustained for the duration of neutral-beam injection. The resulting central-cell ion confinement against axial loss is improved by a factor as large as 9 above that given by magnetic confinement alone. The plasma exhibits gross magnetohydrodynamic stability and microstability. Under some conditions, a residual level of ion cyclotron fluctuations in the end cells heats the central-cell ions and degrades their confinement.

Grubb, D.P.; Anderson, C.A.; Casper, T.A.; Clauser, J.F.; Coensgen, F.H.; Correll, D.L.; Cummins, W.F.; Davis, J.C.; Drake, R.P.; Foote, J.H.

1980-04-02

157

Protein Sequencing with Tandem Mass Spectrometry  

NASA Astrophysics Data System (ADS)

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.

Ziady, Assem G.; Kinter, Michael

158

Electrospray and tandem mass spectrometry in biochemistry.  

PubMed Central

Over the last 20 years, biological MS has changed out of all recognition. This is primarily due to the development in the 1980s of 'soft ionization' methods that permit the ionization and vaporization of large, polar, and thermally labile biomolecules. These developments in ionization mode have driven the design and manufacture of smaller and cheaper mass analysers, making the mass spectrometer a routine instrument in the biochemistry laboratory today. In the present review the revolutionary 'soft ionization' methods will be discussed with particular reference to electrospray. The mass analysis of ions will be described, and the concept of tandem MS introduced. Where appropriate, examples of the application of MS in biochemistry will be provided. Although the present review will concentrate on the MS of peptides/proteins and lipids, all classes of biomolecules can be analysed, and much excellent work has been done in the fields of carbohydrate and nucleic acid biochemistry. PMID:11311115

Griffiths, W J; Jonsson, A P; Liu, S; Rai, D K; Wang, Y

2001-01-01

159

Coevolution of retroelements and tandem zinc finger genes  

PubMed Central

Vertebrate genomes encode large and highly variable numbers of tandem C2H2 zinc finger (tandem ZF) transcription factor proteins. In mammals, most tandem ZF genes also encode a KRAB domain (KZNF proteins). Very little is known about what forces have driven the number and diversity of tandem ZF genes. Recent studies suggest that one role of KZNF proteins is to bind and repress transcription of exogenous retroviruses and their endogenous counterpart LTR retroelements. We report a striking correlation across vertebrate genomes between the number of LTR retroelements and the number of host tandem ZF genes. This correlation is specific to LTR retroelements and ZF genes and was not explained by covariation in other genomic features. We further show that recently active LTR retroelements are correlated with recent tandem ZF gene duplicates across vertebrates. On branches of the primate phylogeny, we find that the appearance of new families of endogenous retroviruses is strongly predictive of the appearance of new duplicate KZNF genes. We hypothesize that retroviral and LTR retroelement burden drives evolution of host tandem ZF genes. This hypothesis is consistent with previously described molecular evolutionary patterns in duplicate ZF genes throughout vertebrates. To further explore these patterns, we investigated 34 duplicate human KZNF gene pairs, all of which underwent an early burst of divergence in the major nucleotide contact residues of their ZF domains, followed by purifying selection in both duplicates. Our results support a host-pathogen model for tandem ZF gene evolution, in which new LTR retroelement challenges drive duplication and divergence of host tandem ZF genes. PMID:21784874

Thomas, James H.; Schneider, Sean

2011-01-01

160

Tandem gene arrays in Trypanosoma brucei: Comparative phylogenomic analysis of duplicate sequence variation  

Microsoft Academic Search

BACKGROUND: The genome sequence of the protistan parasite Trypanosoma brucei contains many tandem gene arrays. Gene duplicates are created through tandem duplication and are expressed through polycistronic transcription, suggesting that the primary purpose of long, tandem arrays is to increase gene dosage in an environment where individual gene promoters are absent. This report presents the first account of the tandem

Andrew P Jackson

2007-01-01

161

Kinetically Stabilized Axisymmetric Tandem Mirrors: Summary of Studies  

SciTech Connect

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

Post, R F

2005-02-08

162

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

E-print Network

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 ...

Shcherbina, Anna

2012-01-01

163

TACHYON: Tandem Execution for Efficient Live Patch Testing Matthew Maurer  

E-print Network

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

Brumley, David

164

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

PubMed

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

Sivula, Kevin

2013-01-01

165

5. GENERAL VIEW OF UNITEDTOD TWIN TANDEM STEAM ENGINE. ...  

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

5. GENERAL VIEW OF UNITED-TOD TWIN TANDEM STEAM ENGINE. - Republic Iron & Steel Company, Youngstown Works, Blooming Mill & Blooming Mill Engines, North of Poland Avenue, Youngstown, Mahoning County, OH

166

Rearrangeability of the Tandem Cascade of Banyan-type Networks  

Microsoft Academic Search

The cascade of two 2^n × 2^n baseline networks in tandem and the cascade of two omega networks through a special interconnection pattern are known to be rearrangeable. These belong to the general problem: for what two banyan-type networks (i.e., bitpermuting unique-routing network) are their tandem cascade a rearrangeable network? We relate the problem to the trace and guide of

Xuesong Tan; Shuo-yen Robert Li; Yuxiu Shen

2005-01-01

167

Patterns of tandem repetition in plant whole genome assemblies  

Microsoft Academic Search

Tandem repeats often confound large genome assemblies. A survey of tandemly arrayed repetitive sequences was carried out in\\u000a whole genome sequences of the green alga Chlamydomonas\\u000a reinhardtii, the moss Physcomitrella patens, the monocots rice and sorghum, and the dicots Arabidopsis thaliana, poplar, grapevine, and papaya, in order to test how these assemblies deal with this fraction of DNA. Our results

Rafael Navajas-Pérez; Andrew H. Paterson

2009-01-01

168

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

NASA Astrophysics Data System (ADS)

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%.

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

2013-12-01

169

Self-assembled growth of tandem nanostructures based on TiO2 mesoporous/ZnO nanowire arrays and their optoelectronic and photoluminescence properties  

NASA Astrophysics Data System (ADS)

Growth of ZnO nanowires within TiO2 mesoporous structures is carried out by hydrothermal method. Structural, optical and thermal characterizations have been carried out by SEM, XRD, EDAX, DTG, TG, PL and UV-Vis spectroscopy. XRD characterization shows that the all diffraction peaks of the tandem nanostructures films can be well indexed to a mixture of hexagonal wurtzite ZnO and anatase TiO2 structures. The UV-Visible absorbance spectrum indicates that the tandem nanostructures based on TiO2 mesoporous/ZnO nanowire arrays have 3.13 eV band gap energy while pure ZnO nanowire and bare TiO2 mesoporous show 3.37 and 3.22 eV band gap energy, respectively. The PL spectra of tandem nanostructures show that the UV, violet and yellow emission peaks appeared at 3.1, 2.6 and 2.3 eV, respectively. It has been shown that from the PL spectra, the enhanced ultraviolet emission of TiO2/ZnO tandem structures is related to the fluorescence resonance energy transfer between TiO2 mesoporous and ZnO nanowires. Thermogravimetric analysis from room temperature to 800 °C has been performed to identify the thermal stability and the amount of tandem TiO2/ZnO structures.

K?l?ç, Bayram; Çelik, Volkan

2015-02-01

170

Novel multiplex format of an extended multilocus variable-number-tandem-repeat analysis of Clostridium difficile correlates with tandem repeat sequence typing.  

PubMed

Subtyping of Clostridium difficile is crucial for outbreak investigations. An extended multilocus variable-number tandem-repeat analysis (eMLVA) of 14 variable number tandem repeat (VNTR) loci was validated in multiplex format compatible with a routine typing laboratory and showed excellent concordance with tandem repeat sequence typing (TRST) and high discriminatory power. PMID:25620018

Jensen, Mie Birgitte Frid; Engberg, Jørgen; Larsson, Jonas T; Olsen, Katharina E P; Torpdahl, Mia

2015-03-01

171

Tandem-mirror technology demonstration facility  

SciTech Connect

Preliminary calculations at LLNL indicate that a Technology Demonstration Facility (TDF) consisting of a tandem mirror machine about the size of TMX could begin providing fusion nuclear engineering data as early as 1988. With high density operation based on physics already demonstrated in TMX, this machine would produce 12 MW of DT neutrons in steady-state from a plasma column 0.08 m in radius and 8 m in length. Allowing space for neutral beam injectors at each end of the column, this would permit testing of blanket modules and components at 1 MW/m/sup 2/ neutron wall load over a cylindrical surface 8 m/sup 2/ in area at a radius of 0.25 m; or one could irradiate thousands of small samples at 2 MW/m/sup 2/ at r = 0.125 m (4 m/sup 2/ area). With improved end-plug physics to be tested in TMX-Upgrade in 1982-83, the wall load at 0.25 m could be increased to 2 MW/m/sup 2/ (4 MW/m/sup 2/ at r = 0.125 m). Construction of the TDF could begin in FY84 and be completed in 4 to 5 years, at a cost roughly estimated as $700M in '81 dollars including engineering and 30% contingency.

Fowler, T.K.; Logan, B.G.

1981-09-18

172

Engineering problems of tandem-mirror reactors  

SciTech Connect

We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper.

Moir, R.W.; Barr, W.L.; Boghosian, B.M.

1981-10-22

173

How tandem power motors improve drilling performance  

SciTech Connect

Tandem power section positive displacement mud-motors (TPS-PDMs) can increase penetration rate when used with tricone and PDC bits. This is achieved by increasing the available output torque and shaft rotational speed by reducing pressure drop per stage in the power section. Early PDMs were single-lobe 1:2 rotor-stator ratio motors. Horsepower produced by these PDMs was a result of high output-shaft rotational speeds and low output torque. Most later PDMs have rotor-stator ratios ranging from 3:4 to 10:11. This change to a higher ratio increased output torque, but also caused a decrease in rotational output-shaft speed. Motor power, a product of torque and speed, has not changed significantly in any particular motor size since the early PDMs. Modern day PDC and tricone ''motor'' bit use requires that PDMs provide high torque and medium to high (180- to 300-rpm) output shaft speeds. This paper discusses the four primary variables in the basic design of any PDM power section for a given diameter tool. Variables are: rotor-stator lobe ratio; lobe spiral pitch; maximum design pressure drop; and number of stages.

Califf, B.; Johnson, M. (Drilex Systems, Inc., Houston, TX (United States))

1994-10-01

174

The Impact of Genome Triplication on Tandem Gene Evolution in Brassica rapa.  

PubMed

Whole genome duplication (WGD) and tandem duplication (TD) are both important modes of gene expansion. However, how WGD influences tandemly duplicated genes is not well studied. We used Brassica rapa, which has undergone an additional genome triplication (WGT) and shares a common ancestor with Arabidopsis thaliana, Arabidopsis lyrata, and Thellungiella parvula, to investigate the impact of genome triplication on tandem gene evolution. We identified 2,137, 1,569, 1,751, and 1,135 tandem gene arrays in B. rapa, A. thaliana, A. lyrata, and T. parvula respectively. Among them, 414 conserved tandem arrays are shared by the three species without WGT, which were also considered as existing in the diploid ancestor of B. rapa. Thus, after genome triplication, B. rapa should have 1,242 tandem arrays according to the 414 conserved tandems. Here, we found 400 out of the 414 tandems had at least one syntenic ortholog in the genome of B. rapa. Furthermore, 294 out of the 400 shared syntenic orthologs maintain tandem arrays (more than one gene for each syntenic hit) in B. rapa. For the 294 tandem arrays, we obtained 426 copies of syntenic paralogous tandems in the triplicated genome of B. rapa. In this study, we demonstrated that tandem arrays in B. rapa were dramatically fractionated after WGT when compared either to non-tandem genes in the B. rapa genome or to the tandem arrays in closely related species that have not experienced a recent whole genome polyploidization event. PMID:23226149

Fang, Lu; Cheng, Feng; Wu, Jian; Wang, Xiaowu

2012-01-01

175

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

SciTech Connect

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.

Ress, D.B.

1988-06-01

176

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

PubMed Central

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

2014-01-01

177

Flow past tandem cylinders under forced vibration  

NASA Astrophysics Data System (ADS)

Flow past two cylinders in tandem arrangement under forced vibration has been studied experimentally employing the hydrogen bubble visualization technique. The Reynolds number, based on the cylinder diameter, is fixed at Re=250. In stationary state of the two cylinders with P/D=2.0, dual vortex shedding frequencies fL (St=0.14) and fH (St=0.18) are identified. fL is associated with the shear layer reattachment behavior and fH is related to the single bluff body behavior. Under a variety of forced vibrations of the two cylinders at a fixed vibration amplitude A/D=0.25, diverse and highly-repetitive vortex patterns are yielded. They are classified into two typical modes—a low-frequency mode and a high-frequency mode. The two modes are represented by two vortex patterns yielded from in-phase vibration of the two cylinders with P/D=2.0 and at vibration frequencies fe?fL and fe?fH. 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, pitch ratio, as well as the vibration type. These affecting factors have been examined in this work, and the associated vortex patterns have been characterized and compared.

Yang, Yingchen; Aydin, Tayfun B.; Ekmekci, Alis

2014-01-01

178

Design of a new tandem wings hybrid airship  

NASA Astrophysics Data System (ADS)

It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform. Through the numerical method, a new tandem wings hybrid airship with both higher utility value and economy efficiency was obtained and its total performance and technical parameters were analyzed in detail. In order to further improve the lift-drag characteristics, we implemented the optimization design for aerodynamic configuration of tandem wings hybrid airship via the response surface method. The results indicate that the tandem wings hybrid airship has considerable volume efficiency and higher aerodynamic characteristics. After optimization, the lift-drag ratio of this hybrid airship was increased by 6.08%. In a given gross lift condition, tandem wings hybrid airship may provide more payload and specific productivity. Furthermore, the size of tandem airship is smaller so the demand for skin flexible materials can be reduced. Results of this study could serve as a new approach to designing buoyancy-lifting integrated hybrid airship.

Li, Feng; Ye, ZhengYin; Gao, Chao

2012-10-01

179

Flow quality experiment in a tandem nozzle wind tunnel at Mach 3  

NASA Astrophysics Data System (ADS)

In this study, the disturbance characterization and flow quality improvement of a newly designed Tandem Nozzle Mach 3 Wind Tunnel are presented. Firstly, a combined modal analysis is conducted to characterize the freestream disturbances with initial set-up of the settling chamber by using a Pitot probe and a hot-wire anemometry. Then, disturbance reduction in the supersonic wind tunnel is investigated by inserting various damping materials into the settling chamber, while a Pitot probe instrumented with Kulite sensor is employed to monitor the variation of the Pitot pressure fluctuation in the test section. Eventually, an optimized configuration of the settling chamber is determined by a combination of certain damping materials. Afterward, the freestream disturbances are re-characterized with the optimized set-up of the settling chamber, and the disturbance level is found to be significantly reduced. Through this study, valuable experience has been acquired for the disturbance reduction in tandem nozzle type supersonic wind tunnel for the first time, which enhances the feasibility of extending the operation range of conventional hypersonic Ludwieg tubes.

Wu, Jie; Zamre, Pradip; Radespiel, Rolf

2015-01-01

180

A tandem mirror hybrid plume plasma propulsion facility  

NASA Technical Reports Server (NTRS)

This paper discusses a novel concept in electrodeless plasma propulsion, in which the materials problems are ameliorated by an electrodeless magnetic confinement scheme borrowed from the tandem mirror approach to controlled thermonuclear fusion. The concept also features a two-stage magnetic nozzle with an annular hypersonic coaxial gas injector near the throat. The nozzle produces hybrid plume by the coaxial injection of hypersonic neutral gas, and 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 tandem mirror plasma propulsion facility is capable of delivering a variable I(sp). The results of numerical simulation of this concept are presented together with those from an experimental tandem-mirror plasma propulsion device.

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

1988-01-01

181

Highly Loaded Fan by Using Tandem Cascade Rotor Blade  

NASA Astrophysics Data System (ADS)

For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could be built. The design of fan with tandem cascades and the fan testing were carried out to develop the high pressure ratio fan for the Air Turbo Ramjet (ATR) propulsion system. The ATR is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds. In particular, high fan pressure ratio contributes to increase the engine thrust during subsonic flight at which the engine does not make use of ram effect. The results of the fan testing indicate that the pressure ratio of 2.2 is achieved in single stage fan.

Hasegawa, Hiroaki; Suga, Shinya; Matsuoka, Akinori

182

Tandem photovoltaic solar cells and increased solar energy conversion efficiency  

NASA Technical Reports Server (NTRS)

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.

Loferski, J. J.

1976-01-01

183

A periodic table of symmetric tandem mismatches in RNA.  

PubMed

The stabilities and structures of a series of RNA octamers containing symmetric tandem mismatches were studied by UV melting and imino proton NMR. The free energy increments for tandem mismatch formation are found to depend upon both mismatch sequence and adjacent base pairs. The observed sequence dependence of tandem mismatch stability is UGGU > GUUG > GAAG > or = AGGA > UUUU > CAAC > or = CUUC approximately UCCU approximately CCCC approximately ACCA approximately AAAA, and the closing base pair dependence is 5'G3'C > 5'C3'G > 5'U3'A approximately 5'A3'U. These results differ from expectations based on models used in RNA folding algorithms and from the sequence dependence observed for folding of RNA hairpins. Imino proton NMR results indicate the sequence dependence is partially due to hydrogen bonding within mismatches. PMID:7533535

Wu, M; McDowell, J A; Turner, D H

1995-03-14

184

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

SciTech Connect

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.

Levin, Daphne [Division of Radiotherapy, Assuta Medical Centers, Tel-Aviv (Israel) and Oncology Institute, Sheba Medical Center, Tel-Hashomer (Israel)], E-mail: daphnelp@yahoo.com; Menhel, Janna; Rabin, Tanya; Pfeffer, M. Raphael; Symon, Zvi [Division of Radiotherapy, Assuta Medical Centers, Tel-Aviv (Israel) and Oncology Institute, Sheba Medical Center, Tel-Hashomer (Israel)

2008-01-01

185

Tandem Catalysis A Highly Efficient and Rapid Approach to Synthetic Elaboration  

E-print Network

catalysis 3.) Auto-tandem catalysis A.) Increasing efficency in palladium catalysed reactions B.) Samarium-pot procedures invloving multiple catalytic transformations. · However, several other terms throughout catalysis? Tandem catalysis: One-pot procedures invloving multiple catalytic transformations. · However

Stoltz, Brian M.

186

Counter-Rotating Tandem Motor Drilling System  

SciTech Connect

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.

Kent Perry

2009-04-30

187

Tandem junction amorphous semiconductor photovoltaic cell  

DOEpatents

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.

Dalal, V.L.

1983-06-07

188

Tandem junction amorphous semiconductor photovoltaic cell  

DOEpatents

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.

Dalal, Vikram L. (Newark, DE)

1983-01-01

189

Verification of automated peptide identifications from proteomic tandem mass spectra  

PubMed Central

Shotgun proteomics yields tandem mass spectra of peptides that can be identified by database search algorithms. When only a few observed peptides suggest the presence of a protein, establishing the accuracy of the peptide identifications is necessary for accepting or rejecting the protein identification. In this protocol, we describe the properties of peptide identifications that can differentiate legitimately identified peptides from spurious ones. The chemistry of fragmentation, as embodied in the ‘mobile proton’ and ‘pathways in competition’ models, informs the process of confirming or rejecting each spectral match. Examples of ion-trap and tandem time-of-flight (TOF/TOF) mass spectra illustrate these principles of fragmentation. PMID:17406459

Tabb, David L; Friedman, David B; Ham, Amy-Joan L

2010-01-01

190

Investigation of flow in centrifugal impeller with tandem inducer  

E-print Network

and the complete test set-up is shown in Fig. 9. The turbocharger was driven by high pressure air which was bled from Garratt gas turbine compressor. Turbocharger speed was controlled by regulating the air supplied from the gate valve. The test compressor has... of the tandem inducer are given in Table l. Table 1 Details of tandem inducer Inducer outer diameters Number of blades Aspect ratio at blade tip 2. 897" 10 0. 94 Space-chord ratio at blade tip 2. 1 AIR INLET (ATMOSPHERE) TEST COMPRESSOR TURBINE...

Nishida, Akira

1976-01-01

191

Lithium hydride doped intermediate connector for high-efficiency and long-term stable tandem organic light-emitting diodes.  

PubMed

Lithium hydride (LiH) is employed as a novel n-dopant in the intermediate connector for tandem organic light-emitting diodes (OLEDs) because of its easy coevaporation with other electron transporting materials. The tandem OLEDs with two and three electroluminescent (EL) units connected by a combination of LiH doped 8-hydroxyquinoline aluminum (Alq3) and 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) demonstrate approximately 2-fold and 3-fold enhancement in current efficiency, respectively. In addition, no extra voltage drop across the intermediate connector is observed. Particularly, the lifetime (T75%) in the tandem OLED with two and three EL units is substantially improved by 3.8 times and 7.4 times, respectively. The doping effect of LiH into Alq3, the charge injection, and transport characteristics of LiH-doped Alq3 are further investigated by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS). PMID:25243919

Ding, Lei; Tang, Xun; Xu, Mei-Feng; Shi, Xiao-Bo; Wang, Zhao-Kui; Liao, Liang-Sheng

2014-10-22

192

Simplified tandem polymer solar cells with an ideal self-organized recombination layer.  

PubMed

A new tandem architecture for printable photovoltaics using a versatile organic nanocomposite containing photoactive and interfacial materials is demonstrated. The nanocomposite forms an ideal self-organized recombination layer via a spontaneous vertical phase separation, which yields a simplified tandem structure fabricated with only four component layers and a high tandem efficiency of 10.8%. PMID:25449142

Kang, Hongkyu; Kee, Seyoung; Yu, Kilho; Lee, Jinho; Kim, Geunjin; Kim, Junghwan; Kim, Jae-Ryoung; Kong, Jaemin; Lee, Kwanghee

2015-02-01

193

Non-metric Similarity Search of Tandem Mass Spectra Including Posttranslational Modifications  

E-print Network

, and these are subsequently analyzed by the tandem mass spec- trometer [2]. However, instead of direct productionNon-metric Similarity Search of Tandem Mass Spectra Including Posttranslational Modifications Jir Prague, Czech Republic http://siret.ms.mff.cuni.cz Abstract In biological applications, the tandem mass

Skopal, Tomas

194

Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry  

E-print Network

Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry EUN, Davis, California 95616 A simple, sensitive, and specific liquid chromatography-tandem mass spectrometry chromatography (HPLC) (17­19), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) (20, 21) method. LC

Hammock, Bruce D.

195

Towards the Prediction of Protein Abundance from Tandem Mass Spectrometry Data  

E-print Network

Towards the Prediction of Protein Abundance from Tandem Mass Spectrometry Data Anthony J Bonner Han the relatively cheap and abundant data available from high-throughput tandem mass spectrometry (MS, Proteomics, Data Min- ing, Proteins, Peptides, Tandem Mass Spectrometry. 1 Introduction. Proteomics

Bonner, Anthony

196

AN ACCURATE AND EFFICIENT ALGORITHM FOR PEPTIDE AND PTM IDENTIFICATION BY TANDEM MASS SPECTROMETRY  

E-print Network

AN ACCURATE AND EFFICIENT ALGORITHM FOR PEPTIDE AND PTM IDENTIFICATION BY TANDEM MASS SPECTROMETRY 117590 Peptide identification by tandem mass spectrometry (MS/MS) is one of the most important problems PTMs. 1. Introduction Peptide identification by tandem mass spectrometry (MS/MS) is a very challenging

Wong, Limsoon

197

On the tandem connection of differential encoding systems: The case of cascaded quantizers  

Microsoft Academic Search

A tandem differential pulse code modulation (DPCM) system structure is developed and the design problem formulated. In the simplified case of cascaded quantizers, the low-to-high and high-to-low bit rate tandems are examined and the performance limitations discussed, Finally the performance of tandem DPCM systems operating at various bit rates is evaluated by simulation.

T. Fischer

1983-01-01

198

THE TANDEM ACCELERATOR EGP-10-1 OF THE CENTRAL INSTITUTE OF NUCLEAR RESEARCH AT ROSSENDORF  

E-print Network

1327 THE TANDEM ACCELERATOR EGP-10-1 OF THE CENTRAL INSTITUTE OF NUCLEAR RESEARCH AT ROSSENDORF H fondamentaux de l'accélérateur tandem EGP 2014 1020141 ainsi que des spécifications techniques. L of the tandem accelerator EGP 2014 10 2014 1are given and technical specifications and additional equipments

Boyer, Edmond

199

Development of high band gap materials for tandem solar cells and simulation studies on mechanical tandem solar cells  

NASA Astrophysics Data System (ADS)

Development of low cost, high efficiency tandem solar cells is essential for large scale adoption of solar energy especially in densely populated regions of the world. In this thesis four-terminal mechanical (stack like) tandem solar cells were evaluated using detailed simulation models and design criteria for selecting candidate materials were established. Since silicon solar cells are low cost and have a multi-giga watt global manufacturing and supply chain capacity already in place then only tandem stacks incorporating silicon as one of the layers in the device was investigated. Two candidate materials which have high band gaps that could be used as top cells in the mechanical tandem device were explored as part of the thesis. Dye-sensitized solar cells (DSSC) sensitized with N719 dye (one of the candidates for the top cell) were fabricated with the goal of enabling a flexible processing path to lower cost. Stainless steel (SS) mesh substrates were used to fabricate anodes for flexible DSSC in order to evaluate them as replacements for more expensive Transparent Conducting Oxides (TCO's). Loss mechanisms in DSSC's due to SS mesh oxidation were quantified and protective coatings to prevent oxidation of SS mesh were developed. The second material which was evaluated for use as the top cell was copper zinc tin sulfide (CZTS). CZTS was deposited through a solution deposition route. Detailed investigations were done on the deposited films to understand the chemistry, crystal structure and its opto-electronic properties. Deposited CZTS films were found to be highly crystalline in <112> direction. The films had a direct band gap of 1.5 eV with absorption coefficient greater than 104 cm -1 in agreement with published values. In the second part of the thesis detailed electrical and optical simulation models of the mechanical tandem solar cells were developed based on the most up-to-date materials physical constants available for each layer. The modeling was used to quantify the various theoretical and practical loss mechanisms in tandem devices. Two configurations were evaluated, first was silicon / germanium tandem cell and the second was gallium arsenide / silicon tandem cell. The simulation models were validated by their close match to the performance of experimental standalone solar cells devices reported in the literature. Finally the efficiency limits of the present generation of high band gap solar cells were discussed. Voltage and current loss of the high band gap solar cells were compared with present generation silicon solar cells and challenges in improving their efficiencies were described.

Vijayakumar, Vishnuvardhanan

200

Incorporation of carbon nanotubes in a hierarchical porous photoanode of tandem quantum dot sensitized solar cells  

NASA Astrophysics Data System (ADS)

The incorporation of multi-walled carbon nanotubes (MWCNT) in quantum dot (QD) sensitized solar cells (QDSC) based on CdSe QDs and quantum rods (QRs) is investigated. The composite hierarchical porous photoanode of titania/CNT is synthesized by sol-gel induced phase separation and QDs/QRs are prepared by the modified solvothermal method. The QDs and QRs form a tandem structure on the hierarchical porous photoanode after deposition by the electrophoretic method. Incorporation of MWCNT in the QDSC photoanode in optimum content (0.32 wt%) causes appreciable enhancement in cells efficiency (about 41% increase). This improvement in efficiency mainly emerges from the beneficial role of MWCNTs in charge injection and collection. The MWCNTs result in longer electron lifetime and higher electron diffusion length, which is confirmed by electrochemical impedance spectroscopy.

Golobostanfard, Mohammad Reza; Abdizadeh, Hossein; Mohajerzadeh, Shamsoddin

2014-08-01

201

Analysis of Short Tandem Repeats by Parallel DNA Threading  

Microsoft Academic Search

The majority of studies employing short tandem repeats (STRs) require investigation of several of these genetic markers. As such, we demonstrate the feasibility of the trinucleotide threading (TnT) approach for scalable analysis of STRs. The TnT method represents a parallel amplification alternative that addresses the obstacles associated with multiplex PCR. In this study, analysis of the STR fragments was performed

Pawel Zajac; Christine Öberg; Afshin Ahmadian

2009-01-01

202

Tandem mass spectrometry of integral membrane proteins for  

E-print Network

Tandem mass spectrometry of integral membrane proteins for top-down proteomics Julian Whitelegge in proteomics has fallen to mass spectrometry (MS) and the significance of the discovery of soft ioni- zation-resolution electrospray-ionization mass spectrometers enable ``top-down'' proteomics, with coverage of bilayer domains. ª

Economou, Tassos

203

Dynamics of tandem bubble interaction in a microfluidic channel  

PubMed Central

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

Yuan, Fang; Sankin, Georgy; Zhong, Pei

2011-01-01

204

Tandem warhead considerations for electronic safety and arming devices  

SciTech Connect

There are four issues that an ESA designer must address when designing a tandem system: (1) warhead detonation shock, (2) warhead detonation ion cloud, (3) warhead detonation electromagnetic pulse, and (4) slapper/sparkgap electromagnetic pulse. Each of these hazards can upset the ESA time delay circuitry which would then either dud the munition or prematurely detonate the main charge. 14 figs.

Dell, D.; Medina, A.

1990-01-01

205

Test of the bunching system for tandem beams  

Microsoft Academic Search

The continuous beams provided by the LNS tandem have to be pulsed into +\\/-3° rf length bursts to reduce the energy spread of the beams extracted from the superconducting cyclotron (DeltaE\\/E < 10-3) and to increase the mean accelerated current. The characteristics of the low energy buncher and of the rebuncher performing this task and the results obtained during preliminary

L. Calabretta; S. Gammino; G. Amata

1993-01-01

206

Simple tandem DNA repeats and human genetic disease  

SciTech Connect

The human genome contains many repeated DNA sequences that vary in complexity of repeating unit from a single nucleotide to a whole gene. The repeat sequences can be widely dispersed or in simple tandem arrays. Arrays of up to 5 or 6 nt are known as simple tandem repeats, and these are widely dispersed and highly polymorphic. Members of one group of the simple tandem repeats, the trinucleotide repeats, can undergo an increase in copy number by a process of dynamic mutation. Dynamic mutations of the CCG trinucleotide give rise to one group of fragile sites on human chromosomes, the rare folate-sensitive group. One member of this group, the fragile X (FRAXA) is responsible for the most common familial form of mental retardation. Another member of the group FRAXE is responsible for a rarer mild form of mental retardation. Similar mutations of AGC repeats give rise to a number of neurological disorders. The expanded repeats are unstable between generations and somatically. The intergenerational instability gives rise to unusual patterns of inheritance - particularly anticipation, the increasing severity and/or earlier age of onset of the disorder in successive generations. Dynamic mutations have been found only in the human species, and possible reasons for this are considered. The mechanism of dynamic mutation is discussed, and a number of observations of simple tandem repeat mutation that could assist in understanding this phenomenon are commented on.

Sutherland, G.R.; Richards, R.I. [Women`s and Children`s Hospital, Adelaide (Australia)

1995-04-25

207

Experimental investigations on tandem compressor cascade performance at low speeds  

Microsoft Academic Search

Minimizing the number of axial flow compressor stages for a specific work output, and thereby lowering the engine size and weight, has always been the designer's goal. Recently, with the emergence of low aspect ratio blades, there has been a renewed interest in tandem blading for maximizing the blade loading further besides improving its off-design performance characteristics.This paper presents aerodynamic

U. K. Saha; B. Roy

1997-01-01

208

Correction of lift coefficient for tandem circular-cascade diffusers  

Microsoft Academic Search

The interaction between two rows of cascades is discussed quantitatively. The lift characteristics of each cascade of a tandem cascade are calculated numerically based on a two-dimensional potential theory, and the result is compared with the lift characteristics of the individual cascades without mutual interaction; then, the correction factors due to mutual interaction are obtained. The performance of a low-solidity

H. Hayami; Y. Senoo; F. Kitayama

1985-01-01

209

Alkyne hydroacylation: switching regioselectivity by tandem ruthenium catalysis.  

PubMed

By using tandem Ru-catalysis, internal alkynes can be coupled with aldehydes for the synthesis of ?,?-unsaturated ketones. The catalyst promotes alkyne transformations with high regioselectivity, with examples that include the differentiation of a methyl vs ethyl substituent on the alkyne. Mechanistic studies suggest that the regioselectivity results from a selective allene formation that is governed by allylic strain. PMID:25608143

Chen, Qing-An; Cruz, Faben A; Dong, Vy M

2015-03-11

210

Electron Heat Conduction in the Phaedrus Tandem Mirror  

Microsoft Academic Search

Experiments to investigate electron heat conduction have been performed on the University of Wisconsin tandem mirror Phaedrus. Electron temperature differences along the magnetic field were generated using a mircowave heat pulse. Probe techniques were developed for the continuous measurement of local electron temperatures with a time resolution of less than one microsecond. Parameter studies indicated that the temperature differences were

Donna Lynn Smatlak

1982-01-01

211

Newborn Screening for Sickle Cell Disease Using Tandem Mass Spectrometry  

E-print Network

cell disease are nowwidespread inNorthAmerican and European countries. Most programs apply isoelectric focusing or HPLC to detect hemoglobin variants. Be-cause tandem mass spectrometry (MS/MS) is being used for screening of inheritedmetabolic disorders and allows protein identification, it was

unknown authors

212

Gas fuelling of Rf-sustained tandem mirror end plugs  

Microsoft Academic Search

The possibility of fuelling pure RF-powered tandem mirror end plugs by gas puffing is considered. It is shown experimentally that gas puffing can lead to significant increases in plug density and that the details of the plug density buildup depended on the antenna locations relative to the central cell and the plug midplane. Large charge-exchange energy loss resulting from the

C. Chan; R. Breun; D. Brouchous; J. Ferron; S. Golovato; R. Goulding; N. Hershkowitz; B. Nelson; J. Pew; L. Yujiri

1984-01-01

213

A census of Tandem system availability between 1985 and 1990  

Microsoft Academic Search

A census of customer outages reported to Tandem showing a clear improvement in the reliability of hardware and maintenance has been taken. It indicates that software is now the major source of reported outages (62%), followed by system operations (15%). This is a dramatic shift from the statistics for 1985. Even after discounting systematic underreporting of operations and environmental outages,

J. Gray

1990-01-01

214

Silicon quantum dot nanostructures for tandem photovoltaic cells  

Microsoft Academic Search

Tandem PV cells – with their increased efficiency due to a multi-band gap approach – usually involve expensive materials and fabrication. Thin film approaches, with an engineered variation in band gap through the use of quantum confinement in Si quantum dots, offer a cheaper alternative. Presented are characterisation and modelling data on fabrication of such Si and Sn QD nanostructures

Gavin Conibeer; Martin Green; Eun-Chel Cho; Dirk König; Young-Hyun Cho; Thipwan Fangsuwannarak; Giuseppe Scardera; Edwin Pink; Yidan Huang; Tom Puzzer; Shujuan Huang; Dengyuan Song; Chris Flynn; Sangwook Park; Xiaojing Hao; Daniel Mansfield

2008-01-01

215

Human tandem repeat sequences in forensic DNA typing  

Microsoft Academic Search

It has been 20 years since the first development of DNA fingerprinting and the start of forensic DNA typing. Ever since, human tandem repeat DNA sequences have been the main targets for forensic DNA analysis. These repeat sequences are classified into minisatellites (or VNTRs) and microsatellites (or STRs). In this brief review, we discuss the historical and current forensic applications

Keiji Tamaki; Alec J. Jeffreys

2005-01-01

216

Relation between Radial and Axial Losses in Tandem Mirrors  

Microsoft Academic Search

The tandem mirror still remains a potentially attractive magnetic confinement geometry. The absence of toroidal curvature and internal plasma parallel current gives the system strongly favorable stability. Additionally, GAMMA-10 experimental results demonstrate that sheared rotation can suppress turbulent radial losses. For an MHD stable system, we investigate the interplay between drift wave (ITG, ETG and Bohm) radial transport and axial

J. Pratt; W. Horton; H. L. Berk

2006-01-01

217

Enhanced oil recovery system  

DOEpatents

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.

Goldsberry, Fred L. (Spring, TX)

1989-01-01

218

Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

219

Development of an advanced spacecraft tandem mass spectrometer  

NASA Technical Reports Server (NTRS)

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.

Drew, Russell C.

1992-01-01

220

Propulsive performance of unsteady tandem hydrofoils in a side-by-side configuration  

NASA Astrophysics Data System (ADS)

Experimental and analytical results are presented on two identical bio-inspired hydrofoils oscillating in a side-by-side configuration. The time-averaged thrust production and power input to the fluid are found to depend on both the oscillation phase differential and the transverse spacing between the foils. For in-phase oscillations, the foils exhibit an enhanced propulsive efficiency at the cost of a reduction in thrust. For out-of-phase oscillations, the foils exhibit enhanced thrust with no observable change in the propulsive efficiency. For oscillations at intermediate phase differentials, one of the foils experiences a thrust and efficiency enhancement while the other experiences a reduction in thrust and efficiency. Flow visualizations reveal how the wake interactions lead to the variations in propulsive performance. Vortices shed into the wake from the tandem foils form vortex pairs rather than vortex streets. For in-phase oscillation, the vortex pairs induce a momentum jet that angles towards the centerplane between the foils, while out-of-phase oscillations produce vortex pairs that angle away from the centerplane between the foils.

Dewey, Peter A.; Quinn, Daniel B.; Boschitsch, Birgitt M.; Smits, Alexander J.

2014-04-01

221

Fully integrated, fully automated generation of short tandem repeat profiles  

PubMed Central

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

2013-01-01

222

Development of tandem time-of-flight instrumentation for the examination of prompt photodissociation of peptides using 193-nm radiation  

E-print Network

........................................................ 37 ix FIGURE Page 19 Tandem mass spectra of C-telopeptide (EKAHDGGR) ......................... 38 20 Tandem mass spectra of [Tyr5, D-Trp6,8,9, Arg10] neurokinin fragment 4-10 amide (DYWVWWR-NH2...)............................................. 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...

Morgan, Joseph William

2006-04-12

223

Trail laying during tandem-running recruitment in the ant Temnothorax albipennis  

NASA Astrophysics Data System (ADS)

Tandem running is a recruitment strategy whereby one ant leads a single naïve nest mate to a resource. While tandem running progresses towards the goal, the leader ant and the follower ant maintain contact mainly by tactile signals. In this paper, we investigated whether they also deposit chemical signals on the ground during tandem running. We filmed tandem-running ants and analysed the position of the gasters of leaders and followers. Our results show that leader ants are more likely to press their gasters down to the substrate compared to follower ants, single ants and transporter ants. Forward tandem-run leaders (those moving towards a new nest site) performed such trail-marking procedures three times more often than reverse tandem leaders (those moving towards an old nest site). That leader ants marked the trails more often during forward tandem runs may suggest that it is more important to maintain the bond with the follower ant on forward tandem runs than on reverse tandem runs. Marked trails on the ground may serve as a safety line that improves both the efficiency of tandem runs and their completion rates.

Basari, Norasmah; Laird-Hopkins, Benita C.; Sendova-Franks, Ana B.; Franks, Nigel R.

2014-07-01

224

Comparing tandem repeats with duplications and excisions of variable degree.  

PubMed

Traditional sequence comparison by alignment employs a mutation model comprised of two events, substitutions and indels (insertions or deletions) of single positions. However, modern genetic analysis knows a variety of more complex mutation events (e.g., duplications, excisions, and rearrangements), especially regarding DNA. With ever more DNA sequence data becoming available, the need to accurately compare sequences which have clearly undergone more complicated types of mutational processes is becoming critical. Herein we introduce a new method for pairwise alignment and comparison of sequences with respect to the special evolution of tandem repeats: substitutions and indels of single positions and, additionally, duplications and excisions of variable degree (i.e., of one or more repeat copies simultaneously) are taken into account. To evaluate our method, we apply it to the spa VNTR (variable number of tandem repeats) cluster of Staphylococcus aureus, a bacterium of high medical importance. PMID:17085848

Sammeth, Michael; Stoye, Jens

2006-01-01

225

III-V/Silicon Lattice-Matched Tandem Solar Cells  

SciTech Connect

A two-junction device consisting of a 1.7-eV GaNPAs junction on a 1.1-eV silicon junction has the theoretical potential to achieve nearly optimal efficiency for a two-junction tandem cell. We have demonstrated a monolithic III-V-on-silicon tandem solar cell in which most of the III-V layers are nearly lattice-matched to the silicon substrate. The cell includes a GaNPAs top cell, a GaP-based tunnel junction (TJ), and a diffused silicon junction formed during the epitaxial growth of GaNP on the silicon substrate. To accomplish this, we have developed techniques for the growth of high crystalline quality lattice-matched GaNPAs on silicon by metal-organic vapor-phase epitaxy.

Geisz, J.; Olson, J.; Friedman, D.; Kurtz, S.; McMahon, W.; Romero, M.; Reedy, R.; Jones, K.; Norman, A.; Duda, A.; Kibbler, A.; Kramer, C.; Young, M.

2005-01-01

226

Nanopyramid structure for ultrathin c-Si tandem solar cells.  

PubMed

Recently, ultrathin crystalline silicon solar cells have gained tremendous interest because they are deemed to dramatically reduce material usage. However, the resulting conversion efficiency is still limited by the incomplete light absorption in such ultrathin devices. In this letter, we propose ultrathin a-Si/c-Si tandem solar cells with an efficient light trapping design, where a nanopyramid structure is introduced between the top and bottom cells. The superior light harvesting results in a 48% and 35% remarkable improvement of the short-circuit current density for the top and bottom cells, respectively. Meanwhile, the use of SiOx mixed-phase nanomaterial helps to provide the maximum light trapping without paying the price of reduced electrical performance, and conversion efficiencies of up to 13.3% have been achieved for the ultrathin tandem cell employing only 8 ?m of silicon, which is 29% higher than the result obtained for the planar cell. PMID:24730470

Li, Guijun; Li, He; Ho, Jacob Y L; Wong, Man; Kwok, Hoi Sing

2014-05-14

227

Single P-N junction tandem photovoltaic device  

DOEpatents

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%.

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

2012-03-06

228

Single P-N junction tandem photovoltaic device  

DOEpatents

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%.

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

2011-10-18

229

Summary of results from the Tandem Mirror Experiment (TMX)  

SciTech Connect

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.

Simonen, T.C. (ed.)

1981-02-26

230

Line-of-sight injection into a tandem accelerator  

NASA Astrophysics Data System (ADS)

A beamline has been designed to accommodate an AMS ion source at the 0° position, injecting in a straight line into the Livermore CAMS tandem accelerator [M.L. Roberts, J.R. Southon, J.C. Davis, I.D. Proctor and D.E. Nelson, Nucl. Instr. and Meth. B56/57 (1991) 882]. An AMS source at this position will allow simultaneous injection of isotopes, providing a testbed for injection techniques which may be used in a low cost RFQ accelerator for tritium AMS measurements. The use of a Wien filter in the beamline will also allow selection of individual isotopes, with the capability of rapid sequential injection of isotopes. The stable isotope current may be collected in a Faraday cup while the radioisotope is injected into the tandem, allowing continuous monitoring of ion source output for calibration purposes. This Wien filter and injection beamline should be adequate for biomedical measurements of 14C as well as for tritium.

Bertsche, Kirk J.

1993-06-01

231

MINIMARS: An attractive small tandem mirror fusion reactor  

NASA Astrophysics Data System (ADS)

Through the innovative design of a novel end plug scheme employing octopole MHD stabilization, we present the conceptual design of MINIMARS, a small commercial fusion reactor based on the tandem mirror principle. The current baseline for MINIMARS has a net electric output of 600 MWe and we have configured the design for short construction times, factory-built modules, inherently safe blanket systems, and multiplexing in station sizes of approx. 600 to 2400 MWe. We demonstrate that the compact octopole end cell provides a number of advantages over the more conventional quadrupole (yin-yang) end cell encountered in the MARS tandem mirror reactor study, and permits ignition to be achieved with much shorter central cell lengths. Accordingly, being economic in small sizes, MINIMARS provides an attractive alternative to the more conventional larger conceptual fusion reactors encountered to date, and would contribute significantly to the lowering of utility financial risk in a developing fusion economy.

Perkins, L. J.; Logan, B. G.; Doggett, J. N.; Devoto, R. S.; Nelson, W. D.; Lousteau, D. C.; Kulcinski, G. L.; Santarius, J. F.; Gordon, J. D.; Campbell, R. B.

1985-11-01

232

Electrostatic plasma-confinement experiments in a tandem mirror system  

SciTech Connect

Results from the tandem mirror experiment are described. The configuration of axial density and potential profiles are created and sustained by neutral-beam injection and gas fueling. Plasma confinement in the center cell is shown to be improved by the end plugs by as much as a factor of 9. The electron temperature is higher than that achieved in our earlier 2XIIB single-cell mirror experiment.

Coensgen, F.H.; Anderson, C.A.; Casper, T.A.; Clauser, J.F.; Condit, W.C.; Correll, D.L.; Cummins, W.F.; Davis, J.C.; Drake, R.P.; Foote, J.H.; Futch, A.H.; Goodman, R.K.; Grubb, D.P.; Hallock, G.A.; Hornady, R.S.; Hunt, A.L.; Logan, B.G.; Munger, R.H.; Nexsen, W.E.; Simonen, T.C.; Slaughter, D.R.; Stallard, B.W.; Strand, O.T.

1980-04-28

233

Generalized recombination in tandem duplications of bacteriophage lambda  

Microsoft Academic Search

Recombination between the tandem duplicated segments of ?b221a106-15 yields unduplicated (“single-copy”) ?b221 phage. The apparent frequency of intramolecular events among these recombinations was determined for both cellular (“Rec”) and bacteriophage (“Red”) generalized recombination systems. The progeny from single-cycle growth experiments with genetically marked duplication phages were treated with EDTA to inactivate all but the singlecopy phages produced by recombination. Analysis

John B. Hays; Robert J. Zagursky

1978-01-01

234

Crux: rapid open source protein tandem mass spectrometry analysis.  

PubMed

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

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

235

R-phycoerythrin-cyanine 5 tandem discerns CD72 polymorphism  

Microsoft Academic Search

By fluorescence analysis, we demonstrated that a fluorochrome tandem composed of R-phycoerythrin and cyanine 5 specifically recognized B cells from SJL, AKR, MRL\\/Mp, and NOD mouse strains, whereas B cells from C57BL\\/6, DBA\\/2, SWR, 129\\/Sv, and BALB\\/c were not stained. A strict correlation was observed between the fixation of the fluorochrome and the pattern of expression of the pan-B cell

Magali Doucet; Neirouz Soussi; Anne-Marie Crain-Denoyelle; Marie-Claude Gendron; Pierre Sanchez

2001-01-01

236

De Novo Peptide Sequencing via Tandem Mass Spectrometry  

Microsoft Academic Search

Peptide sequencing via tandem mass spectrometry (MS\\/MS) is one of the most powerful tools in proteomics for identifying proteins. Because complete genome sequences are accumulat- ing rapidly, the recent trend in interpretation of MS\\/MS spectra has been database search. However, de novo MS\\/MS spectral interpretation remains an open problem typically involving manual interpretation by expert mass spectrometrists. We have developed

Vlado Dancík; Theresa A. Addona; Karl R. Clauser; James E. Vath; Pavel A. Pevzner

1999-01-01

237

Tandem retro-aldol\\/Wittig\\/Michael and related cascade processes  

Microsoft Academic Search

A number of novel tandem sequences initiated by a retro-aldol process are described along with preliminary scope and limitation studies. These include (i) retro-aldol\\/Wittig trapping\\/intramolecular Michael addition, (ii) retro-aldol\\/aza-Wittig\\/intramolecular imine addition, (iii) retro-aldol\\/Henry\\/intramolecular Michael addition and (iv) retro-aldol\\/Knoevenagel\\/intramolecular Michael addition sequences. A range of novel functionalised cyclopentanes, and related systems, are described which should prove to be useful synthetic building

Sandra Beltrán-Rodil; James R. Donald; Michael G. Edwards; Steven A. Raw; Richard J. K. Taylor

2009-01-01

238

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

239

Light-atom neutral beams for tandem mirror end plugs  

Microsoft Academic Search

The advantages and feasibility of neutral beams with Z ? 3 formed from negative ions, accelerated to 0.5–1.0 MeV·amu?1, and neutralized, are investigated for use in tandem mirror reactor end plugs. A reactor plasma physics design incorporating these beams has been done with the result that such a reactor could produce Q's (ratio of fusion power to injected power) of

D. E. Post; L. R. Grisham; J. F. Santarius; G. A. Emmert

1983-01-01

240

Sticky interconnect for solution-processed tandem solar cells.  

PubMed

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

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

2011-06-22

241

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

SciTech Connect

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.

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

1980-12-18

242

Optimal design of high-efficiency tandem cells  

SciTech Connect

Computer analysis indicates that a substantial increase in solar cell conversion efficiencies can be achieved by using two-cell, multi-bandgap tandem structures instead of single-junction cells. Practical AM1 efficiencies of about 30% at one sun and over 30% at multiple suns are to be expected. The further increases in efficiency calculated for a three-cell tandem structure are much smaller and may not justify the added complexity. For inexpensive two-cell tandem modules, Si is preferred for the bottom cell, and the top-cell material should have a bandgap of 1.75 to 1.80 eV. The GaAs-AlAs and GaAs-GaP systems are very attractive candidates for the top cell. Significant advances have been achieved in growing GaAs on Ge-coated Si substrates (for the two-terminal, two-cell structure) and in growing free-standing ultrathin GaAs layers (for the two-terminal or four-terminal structures). These advances should be transferable to the GaAs-AlAs and GaAs-GaP systems.

Fan, J.C.; Palm, B.J.; Tsaur, B.Y.

1982-09-01

243

Tandem cylinder aerodynamic sound control using porous coating  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

244

The mechanics and behavior of cliff swallows during tandem flights.  

PubMed

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

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

2014-08-01

245

Fabrication and characterization of polymer tandem solar cells  

NASA Astrophysics Data System (ADS)

Polymer tandem solar cells were fabricated and characterized. Copolymer poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly((4,4-octyldithieno(3,2-b:20,30-d)silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl) (PSBTBT) were used as p-type semiconductors, and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was used as an n-type semiconductor. The open circuit voltage was improved up to 0.69 V by using the tandem structure of P3HT:PCBM and PSBTBT:PCBM layers as compared with those of P3HT:PCBM and PSBTBT:PCBM single cell of 0.53 V and 0.10 V, respectively. Absorption of the tandem cell was in the range of 400 to 800 nm, which corresponded to a sum of those in P3HT:PCBM and PSBTBT:PCBM single cells.

Maruhashi, Haruto; Suzuki, Atsushi; Akiyama, Tsuyoshi; Oku, Takeo

2013-04-01

246

Tandem Repeat-Containing MITEs in the Clam Donax trunculus  

PubMed Central

Two distinct classes of repetitive sequences, interspersed mobile elements and satellite DNAs, shape eukaryotic genomes and drive their evolution. Short arrays of tandem repeats can also be present within nonautonomous miniature inverted repeat transposable elements (MITEs). In the clam Donax trunculus, we characterized a composite, high copy number MITE, named DTC84. It is composed of a central region built of up to five core repeats linked to a microsatellite segment at one array end and flanked by sequences holding short inverted repeats. The modular composition and the conserved putative target site duplication sequence AA at the element termini are equivalent to the composition of several elements found in the cupped oyster Crassostrea virginica and in some insects. A unique feature of D. trunculus element is ordered array of core repeat variants, distinctive by diagnostic changes. Position of variants in the array is fixed, regardless of alterations in the core repeat copy number. Each repeat harbors a palindrome near the junction with the following unit, being a potential hotspot responsible for array length variations. As a consequence, variations in number of tandem repeats and variations in flanking sequences make every sequenced element unique. Core repeats may be thus considered as individual units within the MITE, with flanking sequences representing a “cassette” for internal repeats. Our results demonstrate that onset and spread of tandem repeats can be more intimately linked to processes of transposition than previously thought and suggest that genomes are shaped by interplays within a complex network of repetitive sequences. PMID:24317975

Šatovi?, Eva; Plohl, Miroslav

2013-01-01

247

Building and searching tandem mass spectral libraries for peptide identification.  

PubMed

Spectral library searching is an emerging approach in peptide identifications from tandem mass spectra, a critical step in proteomic data analysis. Conceptually, the premise of this approach is that the tandem MS fragmentation pattern of a peptide under some fixed conditions is a reproducible fingerprint of that peptide, such that unknown spectra acquired under the same conditions can be identified by spectral matching. In actual practice, a spectral library is first meticulously compiled from a large collection of previously observed and identified tandem MS spectra, usually obtained from shotgun proteomics experiments of complex mixtures. Then, a query spectrum is then identified by spectral matching using recently developed spectral search engines. This review discusses the basic principles of the two pillars of this approach: spectral library construction, and spectral library searching. An overview of the software tools available for these two tasks, as well as a high-level description of the underlying algorithms, will be given. Finally, several new methods that utilize spectral libraries for peptide identification in ways other than straightforward spectral matching will also be described. PMID:21900153

Lam, Henry

2011-12-01

248

Drift wave stability and transport in tandem mirrors  

NASA Astrophysics Data System (ADS)

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.

Pratt, Jane Lillian

249

Multiple-locus variable-number tandem repeat analysis of Salmonella Enteritidis isolates from human and non-human sources using a single multiplex PCR  

PubMed Central

Simplified multiple-locus variable-number tandem repeat analysis (MLVA) was developed using one-shot multiplex PCR for seven variable-number tandem repeats (VNTR) markers with high diversity capacity. MLVA, phage typing, and PFGE methods were applied on 34 diverse Salmonella Enteritidis isolates from human and non-human sources. MLVA detected allelic variations that helped to classify the S. Enteritidis isolates into more evenly distributed subtypes than other methods. MLVA-based S. Enteritidis clonal groups were largely associated with sources of the isolates. Nei's diversity indices for polymorphism ranged from 0.25 to 0.70 for seven VNTR loci markers. Based on Simpson's and Shannon's diversity indices, MLVA had a higher discriminatory power than pulsed field gel electrophoresis (PFGE), phage typing, or multilocus enzyme electrophoresis. Therefore, MLVA may be used along with PFGE to enhance the effectiveness of the molecular epidemiologic investigation of S. Enteritidis infections. PMID:17692097

Cho, Seongbeom; Boxrud, David J; Bartkus, Joanne M; Whittam, Thomas S; Saeed, Mahdi

2007-01-01

250

Exploring the intention of using aspirated cascade to replace tandem cascades  

Microsoft Academic Search

In the present paper, computational fluid dynamics (CFD) simulations were executed to exploring the intent of using aspirated\\u000a cascade to replace tandem cascades. Firstly, the ONERA tandem cascades were investigated, and the performance of the cascades\\u000a at the design point were listed, such as diffusion factor, total pressure loss coefficient, deviation angle etc. For replacing\\u000a the ONERA tandem cascades, a

Shengfeng Zhao; Jianfeng Luo; Xingen Lu; Junqiang Zhu

2010-01-01

251

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

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

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

2014-09-12

252

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

PubMed

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

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

2015-01-01

253

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

PubMed Central

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

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

2015-01-01

254

Conjugated linoleic acid enhances glutathione synthesis and attenuates pathological signs in MRL/MpJ-Fas(lpr) mice.  

PubMed

Conjugated linoleic acid (CLA), a naturally occurring peroxisome proliferator-activated receptor gamma (PPAR gamma) ligand, exhibits proapoptotic, immunomodulatory, and anticancer properties. In this study, we examined the biological effects of CLA administration in the MRL/MpJ-Fas(lpr) mouse, an animal model of systemic lupus erythematosus (SLE). We found that CLA exerted apparently opposed activities in in vitro experiments, depending on its concentration: 100 microM CLA downregulated IFN gamma synthesis and cell proliferation of splenocytes, in association with apoptosis induction and a decrease of intracellular thiols (GSH + GSSG), whereas 25 microM CLA did not significantly influence cell proliferation but enhanced the expression of gamma-glutamylcysteine ligase catalytic subunit (GCLC) and intracellular GSH concentration. Interestingly, the antiproliferative effect at 100 microM was not inhibited by the PPAR gamma antagonist GW9662. In vivo, CLA administration drastically reduced SLE signs (splenomegaly, autoantibodies, and cytokine synthesis), a condition paralleled by the enhancement of GCLC expression and intracellular GSH content. Moreover, CLA administration significantly downregulated nuclear factor kappaB activity independent of PPAR gamma activation and apoptosis induction. In conclusion, enhanced GSH content and GCLC expression in CLA-treated mice suggest a novel biochemical mechanism underlying its immunomodulatory activity and the beneficial effects on murine SLE signs. PMID:16877747

Bergamo, Paolo; Luongo, Diomira; Maurano, Francesco; Mazzarella, Giuseppe; Stefanile, Rosita; Rossi, Mauro

2006-11-01

255

Structural features and ligand binding properties of tandem WW domains from YAP and TAZ, nuclear effectors of the Hippo pathway.  

PubMed

The paralogous multifunctional adaptor proteins YAP and TAZ are the nuclear effectors of the Hippo pathway, a central mechanism of organ size control and stem cell self-renewal. WW domains, mediators of protein-protein interactions, are essential for YAP and TAZ function, enabling interactions with PPxY motifs of numerous partner proteins. YAP has single and double WW domain isoforms (YAP1 and YAP2) whereas only a single WW domain isoform of TAZ has been described to date. Here we identify the first example of a double WW domain isoform of TAZ. Using NMR, we have characterized conformational features and peptide binding of YAP and TAZ tandem WW domains (WW1-WW2). The solution structure of YAP WW2 confirms that it has a canonical three-stranded antiparallel ?-sheet WW domain fold. While chemical shift-based analysis indicates that the WW domains in the tandem WW pairs retain the characteristic WW domain fold, 15N relaxation data show that, within the respective WW pairs, YAP WW1 and both WW1 and WW2 of TAZ undergo conformational exchange. 15N relaxation data also indicate that the linker between the WW domains is flexible in both YAP and TAZ. Within both YAP and TAZ tandem WW pairs, WW1 and WW2 bind single PPxY-containing peptide ligand concurrently and noncooperatively with sub-mM affinity. YAP and TAZ WW1-WW2 bind a dual PPxY-containing peptide with approximately 6-fold higher affinity. Our results indicate that both WW domains in YAP and TAZ are functional and capable of enhanced affinity binding to multi-PPxY partner proteins such as LATS1, ErbB4, and AMOT. PMID:21417403

Webb, Claire; Upadhyay, Abhishek; Giuntini, Francesca; Eggleston, Ian; Furutani-Seiki, Makoto; Ishima, Rieko; Bagby, Stefan

2011-04-26

256

Interpretation of tandem mass spectra obtained from cyclic nonribosomal peptides.  

PubMed

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

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

257

Tandem-repeat protein domains across the tree of life  

PubMed Central

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

Jernigan, Kristin K.

2015-01-01

258

Tandem-repeat protein domains across the tree of life.  

PubMed

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

Jernigan, Kristin K; Bordenstein, Seth R

2015-01-01

259

Numerical Simulation of Cavitation Flow in Tandem Cascade  

Microsoft Academic Search

\\u000a Complex cavitation phenomenon in tandem cascade is investigated numerically. Three-dimensional multi-block structural mesh,\\u000a Finite volume method(FVM), Shear stress transport(SST) turbulence model are employed. Single phase interface tracking model\\u000a is used as the cavitation model. Flow field without cavitation involved is firstly computed as the initial field for further\\u000a cavitation flow simulation. Some results are obtained through the simulation:(1) the position

Can Kang

260

Tandem isomerization/telomerization of long chain dienes.  

PubMed

The first 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 homogeneous Pd(0) precursor complex with a N-heterocyclic carbene (IMes) ligand. Overall conversions approaching 60% were achieved with the best selectivity to telomerization products of 91% attained at 11% conversion. Conversion was markedly higher in the presence of longer-chain alcohol (1-butanol) as the nucleophile (telogen). PMID:24982855

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

2014-01-01

261

Tandem isomerization/telomerization of long chain dienes  

PubMed Central

The first 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 homogeneous Pd(0) precursor complex with a N-heterocyclic carbene (IMes) ligand. Overall conversions approaching 60% were achieved with the best selectivity to telomerization products of 91% attained at 11% conversion. Conversion was markedly higher in the presence of longer-chain alcohol (1-butanol) as the nucleophile (telogen). PMID:24982855

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

2014-01-01

262

Tandemly repeated DNA families in the mouse genome  

PubMed Central

Background Functional and morphological studies of tandem DNA repeats, that combine high portion of most genomes, are mostly limited due to the incomplete characterization of these genome elements. We report here a genome wide analysis of the large tandem repeats (TR) found in the mouse genome assemblies. Results Using a bioinformatics approach, we identified large TR with array size more than 3 kb in two mouse whole genome shotgun (WGS) assemblies. Large TR were classified based on sequence similarity, chromosome position, monomer length, array variability, and GC content; we identified four superfamilies, eight families, and 62 subfamilies - including 60 not previously described. 1) The superfamily of centromeric minor satellite is only found in the unassembled part of the reference genome. 2) The pericentromeric major satellite is the most abundant superfamily and reveals high order repeat structure. 3) Transposable elements related superfamily contains two families. 4) The superfamily of heterogeneous tandem repeats includes four families. One family is found only in the WGS, while two families represent tandem repeats with either single or multi locus location. Despite multi locus location, TRPC-21A-MM is placed into a separated family due to its abundance, strictly pericentromeric location, and resemblance to big human satellites. To confirm our data, we next performed in situ hybridization with three repeats from distinct families. TRPC-21A-MM probe hybridized to chromosomes 3 and 17, multi locus TR-22A-MM probe hybridized to ten chromosomes, and single locus TR-54B-MM probe hybridized with the long loops that emerge from chromosome ends. In addition to in silico predicted several extra-chromosomes were positive for TR by in situ analysis, potentially indicating inaccurate genome assembly of the heterochromatic genome regions. Conclusions Chromosome-specific TR had been predicted for mouse but no reliable cytogenetic probes were available before. We report new analysis that identified in silico and confirmed in situ 3/17 chromosome-specific probe TRPC-21-MM. Thus, the new classification had proven to be useful tool for continuation of genome study, while annotated TR can be the valuable source of cytogenetic probes for chromosome recognition. PMID:22035034

2011-01-01

263

Current- and lattice-matched tandem solar cell  

DOEpatents

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.

Olson, J.M.

1985-10-21

264

Numerical model of tandem organic light-emitting diodes based on a transition metal oxide interconnector layer  

NASA Astrophysics Data System (ADS)

By utilizing a two-step process to express the charge generation and separation mechanism of the transition metal oxides (TMOs) interconnector layer, a numerical model was proposed for tandem organic light emitting diodes (OLEDs) with a TMOs thin film as the interconnector layer. This model is valid not only for an n-type TMOs interconnector layer, but also for a p-type TMOs interconnector layer. Based on this model, the influences of different carrier injection barriers at the interface of the electrode/organic layer on the charge generation ability of interconnector layers were studied. In addition, the distribution characteristics of carrier concentration, electric field intensity and potential in the device under different carrier injection barriers were studied. The results show that when keeping one carrier injection barrier as a constant while increasing another carrier injection barrier, carriers injected into the device were gradually decreased, the carrier generation ability of the interconnector layer was gradually reduced, the electric field intensity at the interface of the organic/electrode was gradually enhanced, and the electric field distribution became nearly linear: the voltage drops in two light units gradually became the same. Meanwhile, the carrier injection ability decreased as another carrier injection barrier increased. The simulation results agree with the experimental data. The obtained results can provide us with a deep understanding of the work mechanism of TMOs-based tandem OLEDs.

Feiping, Lu; Yingquan, Peng; Yongzhong, Xing

2014-04-01

265

A Suboptimal Algorithm for De Novo Peptide Sequencing via Tandem Mass Spectrometry  

E-print Network

given tandem mass spectral data of k ion peaks without searching against protein databases. By transforming the spectral data into a Matrix Spectrum Graph G = (V, E), where |V | = O(k2 ) and |E| = O(k3/menu/denovo.htm. Introduction Protein identification is central to many proteomics projects. Tandem mass spectrometry combined

Chen, Ting

266

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

E-print Network

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

Love, John J.

267

Effects of Environmental Stress on Stability of Tandem Repeat in Escherichia coli O157:H7  

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 exposure to irradiation, elevated temperatures, and starvation conditions. The pO157 plas...

268

Achieving High Performance Polymer Tandem Solar Cells via Novel Materials Design  

E-print Network

GaInP/GaInAs/Ge multijunction solar cells. Appl. Phys. Lett.of tandem/multijunction organic solar cells is nontrivial.multijunction cells and more recently adopted by Kim and Janssen [6,44] in organic tandem solar cells.

Dou, Letian

2014-01-01

269

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...

270

Detection of Neonatal Carnitine Palmitoyltransferase II Deficiency by Expanded Newborn Screening With Tandem Mass Spectrometry  

Microsoft Academic Search

The introduction of tandem mass spec- trometry to newborn screening has substantially ex- panded our ability to diagnose metabolic diseases in the newborn period. We report the first case of neonatal carnitine palmitoyltransferase deficiency II detected by expanded newborn screening with tandem mass spec- trometry. The neonate presented with dysmorphic facial features, structural malformations, renal failure, seizures, and cardiac arrythmias

Simone Albers; Deborah Marsden; Elizabeth Quackenbush; Ann R. Stark; Harvey L. Levy; Mira Irons

2010-01-01

271

Analysis and validation of proteomic data generated by tandem mass spectrometry  

E-print Network

for tandem mass spec- trometry (MS/MS) based proteomics is the fragment ion spectrum (MS/MS spectrumAnalysis and validation of proteomic data generated by tandem mass spectrometry Alexey I Nesvizhskii1,OlgaVitek2 & RuediAebersold3,4 The analysis of the large amount of data generated in mass

Kihara, Daisuke

272

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

ERIC Educational Resources Information Center

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.…

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

2012-01-01

273

Towards the Prediction of Protein Abundance from Tandem Mass Spectrometry Data  

E-print Network

Towards the Prediction of Protein Abundance from Tandem Mass Spectrometry Data Anthony J Bonner Han and abundant data available from high-throughput tandem mass spectrometry (MS/MS). We have developed liver to those in a healthy liver. Modern mass spectrometry makes this possible by enabling

Bonner, Anthony

274

Efficient Simulation of a Tandem Queue with Server Slow-down  

E-print Network

Efficient Simulation of a Tandem Queue with Server Slow-down D.I. Miretskiy , W.R.W. Scheinhardt widespread appli- cation in various domains. One such a variant is the tandem queue with server slow-down, in which the server of the upstream queue reduces its service speed as soon as the down- stream queue

Al Hanbali, Ahmad

275

Highly constrained proteins contain an unexpectedly large number of amino acid tandem repeats  

E-print Network

Highly constrained proteins contain an unexpectedly large number of amino acid tandem repeats Loris Single-amino-acid tandem repeats are very common in mammalian proteins but their function and evolution are still poorly understood. Here we investigate how the variability and prevalence of amino acid repeats

Mularoni, Loris

276

Edinburgh Research Explorer Cross-Lingual Automatic Speech Recognition Using Tandem  

E-print Network

AND LANGUAGE PROCESSING 1 Cross-lingual Automatic Speech Recognition using Tandem Features Partha Lal, Simon Tandem Features' IEEE Transactions on Audio, Speech and Language Processing, vol 21, no. 12, pp. 2506) Published In: IEEE Transactions on Audio, Speech and Language Processing Publisher Rights Statement: © Lal

Edinburgh, University of

277

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

278

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

PubMed Central

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

2013-01-01

279

Recent experiences with the improved EGP-10-1 tandem at Rossendorf  

NASA Astrophysics Data System (ADS)

Since the 4th Tandem Conference in 1978 we have spent considerable effort on the reconstruction of the vacuum system of the tandem EGP-10-1 and on the construction of a Middleton type sputter source. Operational results and preliminary test results concerning the sputter source are presented.

Matthes, H.

1981-05-01

280

Origin and Evolution of Tandem Repeats in the Mitochondrial DNA Control Region of Shrikes (Lanius spp.)  

Microsoft Academic Search

The origin and evolution of a 128-bp tandem repeat in the mtDNA control region of shrikes ( Lanius: Aves) were investigated. The tandem repeat is present in only two species, L. excubitor and L. ludovicianus. In contrast to the variation in repeat number in L. ludovicianus, all individuals of three subspecies of L. excubitor had three repeats. Comparative analysis suggests

Nicholas I. Mundy; Andreas J. Helbig

2004-01-01

281

PERCEPTUALLY WEIGHTED DISTORTION MEASURES AND THE TANDEM CONNECTION OF SPEECH CODECS  

E-print Network

PERCEPTUALLY WEIGHTED DISTORTION MEASURES AND THE TANDEM CONNECTION OF SPEECH CODECS Niranjan, Santa Barbara, CA 93106 {niranjan, gibson}@ece.ucsb.edu ABSTRACT Tandem connections of voice codecs can that Zt is independent of the initial state [3]. For the input source, X, we define the coded output Y

Liebling, Michael

282

Algorithms for Identifying Protein Cross-links via Tandem Mass Spectrometry  

E-print Network

Algorithms for Identifying Protein Cross-links via Tandem Mass Spectrometry Ting Chen Jake Ja e y George M. Church z Abstract Cross-linking technology combined with tandem mass spectrometry is a powerful structures. We studied the problem of detecting the cross-linked peptides and cross-linked amino acids from

Church, George M.

283

High-throughput chiral liquid chromatography/tandem mass spectrometry.  

PubMed

Chiral liquid chromatography is a well-established area of bioanalytical chemistry and is often used during the processes of drug discovery and development. The development and use of a chiral drug require the understanding of the pharmacokinetic characteristics of each of the enantiomers, including potential differences in their absorption, distribution, metabolism, and excretion. Chromatographic techniques coupled to atmospheric pressure ionization-tandem mass spectrometry have shown potential as sensitive and robust tools in the quantitative and qualitative determination of enantiomers in biologic fluids and tissue extracts. However, development of a chiral liquid chromatography method requires time-consuming procedures that are devised empirically. Clearly, there is an incentive to design chromatographic approaches that are easy to use, compatible with mass spectrometry ionization interface conditions, exhibit relatively short run times without compromising sensitivity, and offer a broad analyte specificity. For these reasons, the present paper explores the feasibility of the bonded macrocyclic glycopeptide phases (teicoplanin and vancomycin) for analysis by chiral liquid chromatography/tandem mass spectrometry. Ritalinic acid, pindolol, fluoxetine, oxazepam, propranolol, terbutaline, metoprolol, and nicardipine were tested in this study. Furthermore, an example of a simultaneous chiral LC/MS/MS detection (chromatographic run time approximately 10 min) of four pharmaceutical products resulting in baseline resolutions of all four pairs of enantiomers is presented. Methanol, an MS-compatible mobile phase, was utilized in all the experiments. PMID:10867688

Bakhtiar, R; Tse, F L

2000-01-01

284

Opportunities and limits of AMS with 3-MV tandem accelerators  

NASA Astrophysics Data System (ADS)

With the Vienna Environmental Research Accelerator (VERA, based on a 3-MV tandem accelerator) we have systematically explored the limitations due to terminal voltage, both by modelling and by experiments. If no stable atomic isobars exist, e.g. for 236U or 244Pu, the same detection limits as for large machines have been achieved. In cases where isobar separation is required, the achievable energy is the limitation. To study isobar separation experimentally, we use a new method called ?TOF: the different energy loss in a foil is measured with a time-of-flight (TOF) detector. Separation of 36Cl from 36S is possible. With diamond like carbon (DLC) stripper foils (0.6 ?g/cm 2) and by pushing our Pelletron tandem to 3.6 MV, we achieved a significant increase in energy compared to gas stripping at 3 MV: e.g. 36Cl 7+ at 28.8 MeV instead of 36Cl 5+ at 18 MeV can be used.

Steier, Peter; Golser, Robin; Liechtenstein, Vitaly; Kutschera, Walter; Priller, Alfred; Vockenhuber, Christof; Wallner, Anton

2005-10-01

285

Sequencing technologies and tools for short tandem repeat variation detection.  

PubMed

Short tandem repeats are highly polymorphic and associated with a wide range of phenotypic variation, some of which cause neurodegenerative disease in humans. With advances in high-throughput sequencing technologies, there are novel opportunities to study genetic variation. While available sequencing technologies and bioinformatics tools provide options for mining high-throughput sequencing data, their suitability for analysis of repeat variation is an open question, with tools for quantifying variability in repetitive sequence still in their infancy. We present here a comprehensive survey and empirical evaluation of current sequencing technologies and bioinformatics tools in all stages of an analysis pipeline. While there is not one optimal pipeline to suit all circumstances, we find that the choice of alignment and repeat genotyping tools greatly impacts the accuracy and efficiency by which short tandem repeat variation can be detected. We further note that to detect variation relevant to many repeat diseases, it is essential to choose technologies that offer either long read-lengths or paired-end sequencing, coupled with specific genotyping tools. PMID:24504770

Cao, Minh Duc; Balasubramanian, Sureshkumar; Bodén, Mikael

2015-03-01

286

White organic light-emitting diodes based on tandem structures  

NASA Astrophysics Data System (ADS)

White organic light-emitting diodes made of two electroluminescent (EL) units connected by a charge generation layer were fabricated. Thus, with a tandem structure of indium tin oxide/N ,N'-di(naphthalene-1-yl)-N ,N'-diphenyl-benzidine (NPB)/9,10-bis-(?-naphthyl)-anthrene (ADN)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/tris(8-hydroxyquinoline) aluminum (Alq3)/BCP:Li/V2O5/NPB/Alq3:4-(dicyanomethylene)-2-t-butyle-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran (DCJTB)/Alq3/LiF/Al, a stable white light with Commission Internationale De L'Eclairage chromaticity coordinates from (0.35, 0.32) at 18V to (0.36, 0.36) at 50V was generated. It was clearly seen that the EL spectra consist of red band at 600nm due to DCJTB, green band at 505nm due to Alq3, and blue band at 435nm due to ADN, and the current efficiency and brightness equal basically to the sum of the two EL units. As a result, the tandem devices showed white light emission with a maximum brightness of 10200cd /m2 at a bias of 40V and a maximum current efficiency of 10.7cd/A at a current density of 3.5mA/cm2.

Guo, Fawen; Ma, Dongge

2005-10-01

287

The First Tandem, All-exciplex-based WOLED  

PubMed Central

Exploiting our recently developed bilayer interface methodology, together with a new wide energy-gap, low LUMO acceptor (A) and the designated donor (D) layers, we succeeded in fabricating an exciplex-based organic light-emitting diode (OLED) systematically tuned from blue to red. Further optimization rendered a record-high blue exciplex OLED with ?ext of 8%. We then constructed a device structure configured by two parallel blend layers of mCP/PO-T2T and DTAF/PO-T2T, generating blue and yellow exciplex emission, respectively. The resulting device demonstrates for the first time a tandem, all-exciplex-based white-light OLED (WOLED) with excellent efficiencies ?ext: 11.6%, ?c: 27.7?cd A?1, and ?p: 15.8?ml W?1 with CIE(0.29, 0.35) and CRI 70.6 that are nearly independent of EL intensity. The tandem architecture and blend-layer D/A (1:1) configuration are two key elements that fully utilize the exciplex delay fluorescence, providing a paragon for the use of low-cost, abundant organic compounds en route to commercial WOLEDs. PMID:24895098

Hung, Wen-Yi; Fang, Guan-Cheng; Lin, Shih-Wei; Cheng, Shuo-Hsien; Wong, Ken-Tsung; Kuo, Ting-Yi; Chou, Pi-Tai

2014-01-01

288

36Cl exposure dating with a 3-MV tandem  

NASA Astrophysics Data System (ADS)

36Cl AMS measurements at natural isotopic concentrations have yet been performed only at tandem accelerators with 5 MV terminal voltage or beyond. We have developed a method to detect 36Cl at natural terrestrial isotopic concentrations with a 3-MV system, operated above specifications at 3.5 MV. An effective separation was obtained with an optimized split-anode ionization chamber design (adopted from the ETH/PSI Zurich AMS group), providing a suppression factor of up to 30,000 for the interfering isobar 36S. Despite the good separation, a relatively high sulfur output from the ion source ( 36S -/ 35Cl - ? 4 × 10 -10 for samples prepared from chemically pure reagents), and a possibly cross contamination resulted in a background corresponding to 36Cl/Cl ? 3 × 10 -14. The method was applied to samples containing between 10 5 and 10 6 atoms 36Cl/g rock from sites in Italy and Iran, which were already investigated by other laboratories for surface exposure dating. The 36Cl/Cl ratios in the range from 2 × 10 -13 to 5 × 10 -12 show a generally good agreement with the previous results. These first measurements demonstrate that also 3-MV tandems, constituting the majority of dedicated AMS facilities, are capable of 36Cl exposure dating, which is presently the domain of larger facilities.

Steier, Peter; Forstner, Oliver; Golser, Robin; Kutschera, Walter; Martschini, Martin; Merchel, Silke; Orlowski, Tobias; Priller, Alfred; Vockenhuber, Christof; Wallner, Anton

2010-04-01

289

RepeatsDB: a database of tandem repeat protein structures  

PubMed Central

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

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

290

Functional divergence in tandemly duplicated Arabidopsis thaliana trypsin inhibitor genes.  

PubMed Central

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

Clauss, M J; Mitchell-Olds, T

2004-01-01

291

A Tandem-electrostatic-quadrupole for accelerator-based BNCT  

NASA Astrophysics Data System (ADS)

A project to develop a Tandem-electrostatic-quadrupole (TESQ) accelerator for accelerator-based boron neutron capture therapy (AB-BNCT) is described. A folded Tandem, with 1.25 MV terminal voltage, combined with an electrostatic quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7Li(p, n) 7Be reaction slightly beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7Li(p, n) 7Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT.

Kreiner, A. J.; Kwan, J. W.; Burlón, A. A.; Di Paolo, H.; Henestroza, E.; Minsky, D. M.; Valda, A. A.; Debray, M. E.; Somacal, H.

2007-08-01

292

A numerical parametric study on hydrofoil interaction in tandem  

NASA Astrophysics Data System (ADS)

Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM) and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM). RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid

Kemal, Omer

2015-03-01

293

The first tandem, all-exciplex-based WOLED.  

PubMed

Exploiting our recently developed bilayer interface methodology, together with a new wide energy-gap, low LUMO acceptor (A) and the designated donor (D) layers, we succeeded in fabricating an exciplex-based organic light-emitting diode (OLED) systematically tuned from blue to red. Further optimization rendered a record-high blue exciplex OLED with ?(ext) of 8%. We then constructed a device structure configured by two parallel blend layers of mCP/PO-T2T and DTAF/PO-T2T, generating blue and yellow exciplex emission, respectively. The resulting device demonstrates for the first time a tandem, all-exciplex-based white-light OLED (WOLED) with excellent efficiencies ?(ext): 11.6%, ?(c): 27.7?cd A(-1), and ?(p): 15.8?ml W(-1) with CIE(0.29, 0.35) and CRI 70.6 that are nearly independent of EL intensity. The tandem architecture and blend-layer D/A (1:1) configuration are two key elements that fully utilize the exciplex delay fluorescence, providing a paragon for the use of low-cost, abundant organic compounds en route to commercial WOLEDs. PMID:24895098

Hung, Wen-Yi; Fang, Guan-Cheng; Lin, Shih-Wei; Cheng, Shuo-Hsien; Wong, Ken-Tsung; Kuo, Ting-Yi; Chou, Pi-Tai

2014-01-01

294

The First Tandem, All-exciplex-based WOLED  

NASA Astrophysics Data System (ADS)

Exploiting our recently developed bilayer interface methodology, together with a new wide energy-gap, low LUMO acceptor (A) and the designated donor (D) layers, we succeeded in fabricating an exciplex-based organic light-emitting diode (OLED) systematically tuned from blue to red. Further optimization rendered a record-high blue exciplex OLED with ?ext of 8%. We then constructed a device structure configured by two parallel blend layers of mCP/PO-T2T and DTAF/PO-T2T, generating blue and yellow exciplex emission, respectively. The resulting device demonstrates for the first time a tandem, all-exciplex-based white-light OLED (WOLED) with excellent efficiencies ?ext: 11.6%, ?c: 27.7 cd A-1, and ?p: 15.8 ml W-1 with CIE(0.29, 0.35) and CRI 70.6 that are nearly independent of EL intensity. The tandem architecture and blend-layer D/A (1:1) configuration are two key elements that fully utilize the exciplex delay fluorescence, providing a paragon for the use of low-cost, abundant organic compounds en route to commercial WOLEDs.

Hung, Wen-Yi; Fang, Guan-Cheng; Lin, Shih-Wei; Cheng, Shuo-Hsien; Wong, Ken-Tsung; Kuo, Ting-Yi; Chou, Pi-Tai

2014-06-01

295

An unprecedented, tandem Aldol-Grob reaction sequence  

SciTech Connect

The authors report an unprecedented, tandem Aldol-Grob sequence involving the reaction of ketones with aromatic aldehydes in nonnucleophilic solvents in the presence of boron trifluoride. Although a detailed study of the reaction mechanism has not yet been completed, the consistent formation of (E)-alkene products, as well as the fact that aromatic aldehydes appear to be required, would point toward the intermediacy of a carbocation derivative. A reasonable mechanism would involve the formation of the mixed aldol followed by the formation and subsequent nonsynchronous ring opening of a lactol. The proposed fragmentation is reminiscent of two-step Grob fragmentations that have been reported for N-halo-{alpha}-amino acids and cyclobutane hemiacetals as well as the acid-catalyzed fragmentation of {beta}-hydroxy acetals. The authors examined the effect of various acids on the reaction sequence in order to ascertain which would be most efficient. They conclude that boron trifluoride is the most effective of the acids studied in achieving the new tandem condensation-cleavage sequence.

Kabalka, G.W.; Tejedor, D.; Li, N.S.; Malladi, R.R.; Trotman, S. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States)

1998-09-18

296

Origin and evolution of tandem repeats in the mitochondrial DNA control region of shrikes (Lanius spp.).  

PubMed

The origin and evolution of a 128-bp tandem repeat in the mtDNA control region of shrikes (Lanius: Aves) were investigated. The tandem repeat is present in only two species, L. excubitor and L. ludovicianus. In contrast to the variation in repeat number in L. ludovicianus, all individuals of three subspecies of L. excubitor had three repeats. Comparative analysis suggests that a short direct repeat, and a secondary structure including the tandem repeat and a downstream inverted repeat, may be important in the origin of the tandem repeat by slipped-strand mispairing and its subsequent turnover. Homogenization of repeat sequences is most simply explained by expansion and contraction of the repeat array. Surprisingly, mtDNA sequences from L. excubitor were found to be paraphyletic with respect to L. ludovicianus. These results show the utility of a comparative analysis for insights into the evolutionary dynamics of mtDNA tandem repeats. PMID:15486698

Mundy, Nicholas I; Helbig, Andreas J

2004-08-01

297

Numerical investigation & comparison of a tandem-bladed turbocharger centrifugal compressor stage with conventional design  

NASA Astrophysics Data System (ADS)

Extensive numerical investigations of the performance and flow structure in an unshrouded tandem-bladed centrifugal compressor are presented in comparison to a conventional compressor. Stage characteristics are explored for various tip clearance levels, axial spacings and circumferential clockings. Conventional impeller was modified to tandem-bladed design with no modifications in backsweep angle, meridional gas passage and camber distributions in order to have a true comparison with conventional design. Performance degradation is observed for both the conventional and tandem designs with increase in tip clearance. Linear-equation models for correlating stage characteristics with tip clearance are proposed. Comparing two designs, it is clearly evident that the conventional design shows better performance at moderate flow rates. However; near choke flow, tandem design gives better results primarily because of the increase in throat area. Surge point flow rate also seems to drop for tandem compressor resulting in increased range of operation.

Danish, Syed Noman; Qureshi, Shafiq Rehman; EL-Leathy, Abdelrahman; Khan, Salah Ud-Din; Umer, Usama; Ma, Chaochen

2014-12-01

298

Enhancing Children  

ERIC Educational Resources Information Center

The "enhancement agenda" in educational policy is based on the idea that "something affective", which supports and improves learning, can be a) measured and b) enhanced. This idea is explored, and it is argued that the identity of the "something" that the enhancement agenda seeks to enhance is fatally obscure, as is the idea of measurable…

Cigman, Ruth

2008-01-01

299

Identification of polymorphic tandem repeats by direct comparison of genome sequence from different bacterial strains : a web-based resource  

Microsoft Academic Search

BACKGROUND: Polymorphic tandem repeat typing is a new generic technology which has been proved to be very efficient for bacterial pathogens such as B. anthracis, M. tuberculosis, P. aeruginosa, L. pneumophila, Y. pestis. The previously developed tandem repeats database takes advantage of the release of genome sequence data for a growing number of bacteria to facilitate the identification of tandem

Gilles Vergnaud

2004-01-01

300

Wind stress measurements from the QuikSCAT-SeaWinds scatterometer tandem mission and the impact on an ocean model  

E-print Network

Wind stress measurements from the QuikSCAT-SeaWinds scatterometer tandem mission and the impact by the QuikSCAT-SeaWinds scatterometer tandem mission (April­October 2003) and their impact on ocean model simulation. The diurnal variability captured by twice-daily scatterometer wind from the tandem mission

Talley, Lynne D.

301

Cross-lingual Portability of MLP-Based Tandem Features A Case Study for English and Hungarian  

E-print Network

-lingual adaptation. Tandem ASR is particularly well suited to such adaptation, as it includes two cascaded modelling, as it consists of two cascaded statistical modelling steps. In Sections 2-3 we develop a tandem recognizer usingCross-lingual Portability of MLP-Based Tandem Features ­ A Case Study for English and Hungarian L

Edinburgh, University of

302

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

SciTech Connect

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}.

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

1996-12-31

303

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

DOEpatents

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.

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

2010-09-07

304

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

DOEpatents

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.

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

2007-01-23

305

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

DOEpatents

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.

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

1997-01-01

306

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

NASA Astrophysics Data System (ADS)

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.

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

307

Distinguishing endogenous D-amino acid-containing neuropeptides in individual neurons using tandem mass spectrometry  

PubMed Central

RNA-based protein synthesis produces L-amino acid-containing proteins and peptides. D-amino acid-containing peptides (DAACPs) can be generated from L-amino acid peptides via post-translational modification. In the nervous system, the conformational change of a single L-amino acid in a peptide to its D-form results in altered bioactivity, with some DAACPs having orders-of-magnitude enhanced efficacy. However, this modification is often overlooked when characterizing endogenous peptides. Here, using matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry, neuropeptides that have the second residue isomerized to the D-isoform are distinguished from their L-epimers via differences in the relative amounts of specific fragment ions during tandem MS. By choosing the appropriate fragment ions, and in some cases with the use of metal adducts, epimer discrimination is optimized. Specifically, the cardioexcitatory peptide Asn-DTrp-Phe-amide (NdWFa) was assayed directly from neurons isolated from the sea slug Aplysia californica; the fraction of the peptide with the second residue (W) in the D- versus L-form was 90 ± 10%. We demonstrate that this approach is well suited for confirming DAACPs directly from cells and tissue, advancing our understanding of the L to D modification and the role it plays in cell-to-cell signaling. PMID:21388150

Bai, Lu; Romanova, Elena V.; Sweedler, Jonathan V.

2011-01-01

308

Behavior of the plasma in the anchor cell of the GAMMA 10 tandem mirror  

SciTech Connect

Anchor cells of the GAMMA 10 tandem mirror are composed of minimum-B magnetic field configuration. Behavior of the plasma in the anchor cell is studied using puffing gas flow rate (PGFR) modulation and by covering some parts of the flux tube of each anchor cell by conducting plates (APs). Ambient neutral pressure is decreased by PGFR modulation during axial/potential confinement in both cases without and with APs and it is found that both line density (nl{sub EA}) and diamagnetism (dm{sub EA}) of the anchor cell plasma increase. Lower neutral pressure in the minimum-B region is investigated during the floated APs and significant improvement of the GAMMA 10 plasma parameters is observed. Possible explanations of the experimental results are given from the viewpoint of ambient neutral pressure oriented anchor plasma behavior. Probable reasons of enhanced ambient neutral pressure in the anchor cell and adverse effects of these neutrals on GAMMA 10 plasma parameters are also pointed out.

Islam, Md. Khairul; Nakashima, Yousuke; Higashizono, Yuta; Cho, Teruji [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

2006-08-01

309

Neutral Beam Injection Experiments and Related Behavior of Neutral Particles in the GAMMA 10 Tandem Mirror  

SciTech Connect

Results of neutral beam injection (NBI) experiments in the GAMMA 10 tandem mirror plasmas are presented together with the neutral particle behavior observed in the experiments. A hydrogen neural beam was injected into the hot-ion-mode plasmas by using the injector installed in the central-cell for the plasma heating and fueling. High-energy ions produced by NBI were observed and its energy distribution was measured for the first time with a neutral particle analyzer installed in the central-cell. The temporal and spatial behavior of hydrogen was observed with axially aligned H{sub {alpha}} detectors installed from the central midplane to anchor-cell. Enhancement of hydrogen recycling due to the beam injection and the cause of the observed decrease in plasma diamagnetism are discussed. The Monte-Carlo code DEGAS for neutral transport simulation was applied to the GAMMA 10 central-cell and a 3-dimensional simulation was performed in the NBI experiment. Localization of neutral particle during the beam injection is investigated based on the simulation and it was found that the increased recycling due to the beam injection was dominant near the injection port.

Nakashima, Y. [Plasma Research Center, University of Tsukuba (Japan); Watanabe, K. [Plasma Research Center, University of Tsukuba (Japan); Higashizono, Y. [Plasma Research Center, University of Tsukuba (Japan); Ohki, T. [Plasma Research Center, University of Tsukuba (Japan); Ogita, T. [Plasma Research Center, University of Tsukuba (Japan); Shoji, M. [National Institute for Fusion Science(Japan); Kobayashi, S. [Institute of Advanced Energy, Kyoto University (Japan); Islam, M.K. [Plasma Research Center, University of Tsukuba (Japan); Kubota, Y. [Plasma Research Center, University of Tsukuba (Japan); Yoshikawa, M. [Plasma Research Center, University of Tsukuba (Japan); Kobayashi, T. [Plasma Research Center, University of Tsukuba (Japan); Yamada, M. [Plasma Research Center, University of Tsukuba (Japan); Murakami, R. [Plasma Research Center, University of Tsukuba (Japan); Cho, T. [Plasma Research Center, University of Tsukuba (Japan)

2005-01-15

310

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

PubMed

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

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

2015-03-01

311

Quantification of peramivir in dog plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization.  

PubMed

Peramivir is a novel influenza neuraminidase inhibitor used for anti-influenza. In this article, a novel method was developed to determine peramivir in dog plasma using a derivatization treatment step to increase the retention time and enhance the signal intensity. The sample preparation consisted of a protein precipitation extraction followed by derivatization with 10M hydrochloric acid-methanol (10:90, v/v) and determined by liquid chromatography coupled with tandem mass spectrometry. The selected reaction monitoring mode of the positive ion was performed and the precursor to the product ion transitions of m/z 343?284 and m/z 299?152 were used to measure the derivative of peramivir and Ro 64-0802 (internal standard, an active metabolite of oseltamivir). The chromatographic separation was achieved using a ZORBAX RX-C8 (2.0mm×150mm×5?m) analytical column with an isocratic mobile phase composed of acetonitrile-water-formic acid (30:70:0.1, v/v/v, 0.2mL/min). The method was linear over a concentration range of 0.25-250ng/mL. The average intra-day/inter-day precision values were 4.04-8.17% and 3.02-7.08%, respectively, while the average accuracy value was 93.99-106.48%. This method has been successfully applied to the preclinical dog research of peramivir following intragastric administration. PMID:24280376

Li, Xin; Li, Ying; Wang, Juan; Wang, Lili; Zhong, Wu; Ruan, Jinxiu; Zhang, Zhenqing

2014-01-01

312

Malignant Solitary Fibrous Tumor of Tandem Lesions in the Skull and Spine  

PubMed Central

A Solitary Fibrous Tumor (Sft) Is A Rare Neoplasm Originated From The Pleura, But They Can Occur In A Variety Of Extrathoracic Regions. Although Many Cases Of Primary Sft Have Been Reported, There Are Extremely Rare Repots To Date Of A Malignant Sft In The Spine Or Skull. A 54-year-woman Visited Our Hospital Due To Low Back Pain And Both Leg Radiating Pain. Several Imaging Studies Including Magnetic Resonance Imaging And Computed Tomography Revealed Expansive Enhanced Lesions In The Occipital Bone, T8, S1-2, And Ilium, With Neural Tissue Compression. We Performed Surgical Resection Of The Tumor In Each Site, And Postoperative Radiosurgery And Chemotherapy Were Performed. However, After Six Months, Tumors Were Recurred And Metastasized In Multiple Regions Including Whole Spine And Lung. The Authors Report Here The First Case Of Patient With Malignant Sft Of Tandem Lesions In The Various Bony Structures, Including Skull, Thoracic Spine, And Sacral Spine, With A Rapid Recurrence And Metastasis. Although Malignant Sft Is Extremely Rare, It Should Be Considered In The Differential Diagnosis And Carful Follow-up Is Needed. PMID:24278657

Son, Seong; Jeong, Dong-Hae; Yoo, Chan Jong

2013-01-01

313

TOPEX/Poseidon and Jason-1 Formation Flying; Applications of the Tandem Mission Data  

NASA Astrophysics Data System (ADS)

Jason-1 will join a suite of oceanographic satellites in Earth orbit following its planned December 2001 launch from Vandenburg Air Force Base in California. Jason-1 will be positioned along the same groundtrack that TOPEX/Poseidon has faithfully flown for over nine years. After a brief period of Jason-1 measurement calibration and validation, TOPEX/Poseidon will be maneuvered to an interleaved groundtrack, half-way between the tracks of its former path. TOPEX/Poseidon will continue collecting its valuable data in this new orbital position, thereby increasing the altimetry dataset by a factor of two. Jason-1 will remain on the original TOPEX/Poseidon groundtrack and assume its role as the primary source for many researchers and operational entities utilizing this valued oceanographic data. Jason-1 has a primary mission phase of three years, with a projected five year extended life. As long as TOPEX/Poseidon remains operational, this enhanced dual dataset can provide an unprecedented opportunity for improved resolution in ocean surface topography measurement that may never again be possible. The Tandem Mission phase, as this formation-flying period is described, will be a unique and valuable opportunity for many potentially new scientific discoveries and practical applications. These include, but may not be limited to, ocean eddy velocity and interaction with mean currents, Rossby wave dynamics, coastal currents and tides, oceanic internal tides, fisheries management, ship routing, ocean debris tracking, and offshore operations.

Srinivasan, M.; Fu, L.

2001-12-01

314

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

PubMed

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 24g/L (by 26%) and from 6.7 to 9.7gL(-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

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

2015-03-01

315

2,3,7,8-tetrachlorodibenzo-p-dioxin, an exogenous modulator of the 3'alpha immunoglobulin heavy chain enhancer in the CH12.LX mouse cell line.  

PubMed

Transcriptional regulation of the Ig heavy chain gene involves several regulatory elements, including the 3'alpha enhancer, which is composed of four distinct regulatory domains. DNA binding sites for several transcription factors, including B cell-specific activator protein, nuclear factor for immunoglobulin kappa chain in B cells, and octamer have been identified within the 3'alpha enhancer domains and are believed to be important in regulating 3'alpha enhancer activity. We have identified an additional DNA binding motif, the dioxin-responsive element (DRE), which can contribute to 3'alpha enhancer regulation. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a known disrupter of B cell differentiation (i.e., decreased plasma cell formation, inhibition of micro heavy chain expression, and suppression of IgM secretion), induces binding of the aryl hydrocarbon receptor (AhR) nuclear complex to DREs. TCDD also induces AhR binding to the hypersensitive (hs)4 domain of the 3'alpha enhancer. Interestingly, TCDD enhances LPS-induced activation of the hs4 domain but profoundly inhibits LPS-induced activation of the complete 3'alpha enhancer. Furthermore, site-directed mutational analysis demonstrated that a DRE and kappaB element in the hs4 domain is modulated by TCDD in lipopolysaccharide-activated B cells. We propose that the AhR is a novel transcriptional regulator of the 3'alpha enhancer, which can mediate, at least in part, the effects of TCDD on the 3'alpha enhancer and its domains, putatively contributing to a marked suppression of IgM production. PMID:14718603

Sulentic, Courtney E W; Zhang, Wei; Na, Yong Joo; Kaminski, Norbert E

2004-04-01

316

[Mouse centromeric tandem repeats in silico and in situ].  

PubMed

The search for all sequences containing centromeric (CEN) minor satellite (MiSat) or pericentromeric (peri-CEN) mouse major satellite (MaSat) was conducted in the whole genome shotgun (WGS) database. The sequences were checked for the presence of the known dispersed repeats using the Censor software. The presence of tandem repeats was tested using Tandem Repeat Finder (TRF). Monotonous MiSat and MaSat arrays and MaSat to MiSat array transitions were detected. Moreover, two other types of contacts were revealed: (1) MiSat transition to fragments of retroelements LINE and IAP (ERV family, intracisternal A-type particles), mainly to ORF2 and 5'-LTR containing elements; (2) MaSat transition to two tandem repeats with monomers 21 bp and 31 bp in size. The presence of the MiSat/IAP transition could be checked experimentally. The common DNA motif among the IAP fragments close to MiSat was isolated. IAP-specific primers were constructed and the fragments obtained in PCR with LAP and MiSat primers compiled the plasmid vector library. Clone n51 with the maximum length of the possible insertion (approximately no. 800 bp) was selected from the library. FISH on extended chromatin fibers (fiberFISH) carried out on the n51 clone demonstrated that the main signal definitely belonged to CEN. However, the signals on the chromosome arms were also detected that could be due to the partial homology of n51 to the dispersed repeats. The duplicated fiberFISH with MiSat and n51 allowed to measure the distances between the fragments. The previously obtained MS3 sequence has some homology to IAP and CEN localization. Accordingly, the regular associations of MiSat with IAP retroelements were shown in silico and in situ. Together with the published data, the present findings suggest that retroelements or their fragments may be essential components of the normal centromere of higher eukaryotes. PMID:21061622

Komissarov, A S; Kuznetsova, I S; Podgornaia, O I

2010-09-01

317

Detection of dispersed short tandem repeats using reversible jump Markov chain Monte Carlo.  

PubMed

Tandem repeats occur frequently in biological sequences. They are important for studying genome evolution and human disease. A number of methods have been designed to detect a single tandem repeat in a sliding window. In this article, we focus on the case that an unknown number of tandem repeat segments of the same pattern are dispersively distributed in a sequence. We construct a probabilistic generative model for the tandem repeats, where the sequence pattern is represented by a motif matrix. A Bayesian approach is adopted to compute this model. Markov chain Monte Carlo (MCMC) algorithms are used to explore the posterior distribution as an effort to infer both the motif matrix of tandem repeats and the location of repeat segments. Reversible jump Markov chain Monte Carlo (RJMCMC) algorithms are used to address the transdimensional model selection problem raised by the variable number of repeat segments. Experiments on both synthetic data and real data show that this new approach is powerful in detecting dispersed short tandem repeats. As far as we know, it is the first work to adopt RJMCMC algorithms in the detection of tandem repeats. PMID:22753023

Liang, Tong; Fan, Xiaodan; Li, Qiwei; Li, Shuo-Yen R

2012-10-01

318

Detection of dispersed short tandem repeats using reversible jump Markov chain Monte Carlo  

PubMed Central

Tandem repeats occur frequently in biological sequences. They are important for studying genome evolution and human disease. A number of methods have been designed to detect a single tandem repeat in a sliding window. In this article, we focus on the case that an unknown number of tandem repeat segments of the same pattern are dispersively distributed in a sequence. We construct a probabilistic generative model for the tandem repeats, where the sequence pattern is represented by a motif matrix. A Bayesian approach is adopted to compute this model. Markov chain Monte Carlo (MCMC) algorithms are used to explore the posterior distribution as an effort to infer both the motif matrix of tandem repeats and the location of repeat segments. Reversible jump Markov chain Monte Carlo (RJMCMC) algorithms are used to address the transdimensional model selection problem raised by the variable number of repeat segments. Experiments on both synthetic data and real data show that this new approach is powerful in detecting dispersed short tandem repeats. As far as we know, it is the first work to adopt RJMCMC algorithms in the detection of tandem repeats. PMID:22753023

Liang, Tong; Fan, Xiaodan; Li, Qiwei; Li, Shuo-yen R.

2012-01-01

319

Tandem demodulation lock-in amplifier based on digital signal processor for dual-modulated spectroscopy  

NASA Astrophysics Data System (ADS)

Dual-modulated spectroscopy is one of the most powerful methods in the measurement of modulation spectroscopy. Here we develop a tandem lock-in amplifier (LIA) based on digital signal processor to implement a novel algorithm of tandem demodulation. The theoretical analysis of demodulation algorithm is presented, and the implementation of this tandem LIA is described in detail. Compared to the traditional demodulating way with two LIAs in cascade, this tandem LIA eliminates the extra quantization error of redundant analog-to-digital and digital-to-analog conversions and removes the limitation to the time constant in the commercial LIA, hence lowers the requirement of frequency ratio in dual-modulated spectroscopy. The applications are given as examples in the photoreflectance (PR) measurements of GaAs (100) thin film and GaSb bulk material, respectively, at the different optical energy regions. The experimental results indicate that this tandem is well capable of PR spectra measurement with good PR lineshapes and reasonable signal noise ratio. A brief comparison of GaAs PR results between tandem LIA and two LIAs is made to prove the efficiency and advantages of the tandem LIA.

Qin, Jianhuan; Huang, Zhiming; Ge, Yujian; Hou, Yun; Chu, Junhao

2009-03-01

320

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

321

Targeted Tandem Duplication of a Large Chromosomal Segment in Aspergillus oryzae  

PubMed Central

We describe here the first successful construction of a targeted tandem duplication of a large chromosomal segment in Aspergillus oryzae. The targeted tandem chromosomal duplication was achieved by using strains that had a 5?-deleted pyrG upstream of the region targeted for tandem chromosomal duplication and a 3?-deleted pyrG downstream of the target region. Consequently, strains bearing a 210-kb targeted tandem chromosomal duplication near the centromeric region of chromosome 8 and strains bearing a targeted tandem chromosomal duplication of a 700-kb region of chromosome 2 were successfully constructed. The strains bearing the tandem chromosomal duplication were efficiently obtained from the regenerated protoplast of the parental strains. However, the generation of the chromosomal duplication did not depend on the introduction of double-stranded breaks (DSBs) by I-SceI. The chromosomal duplications of these strains were stably maintained after five generations of culture under nonselective conditions. The strains bearing the tandem chromosomal duplication in the 700-kb region of chromosome 2 showed highly increased protease activity in solid-state culture, indicating that the duplication of large chromosomal segments could be a useful new breeding technology and gene analysis method. PMID:24837372

Sato, Atsushi; Ogawa, Masahiro; Hanya, Yoshiki; Oguma, Tetsuya

2014-01-01

322

Short-tandem repeat analysis in seven Chinese regional populations  

PubMed Central

In the present study, we investigated the application of 13 short tandem repeat (STR) loci (D13S317, D7S820, TH01, D16S539, CSFIPO, VWA, D8S1179, TPOX, FGA, D3S1358, D21S11, D18S51 and D5S818) routinely used in forensic analysis, for delineating population relationships among seven human populations representing the two major geographic groups, namely the southern and northern Chinese. The resulting single topology revealed pronounced geographic and population partitioning, consistent with the differences in geographic location, languages and eating habits. These findings suggest that forensic STR loci might be particularly powerful tools in providing the necessary fine resolution for reconstructing recent human evolutionary history. PMID:21637565

2010-01-01

323

Nonambipolar radial particle transport in a tandem mirror  

SciTech Connect

Nonambipolar transport has been measured in the tandem mirror TMX-U (Phys. Rev. Lett. 53, 783 (1984)) by applying charge conservation to the measured electron currents to the end walls. The resulting confinement time tau/sub perpendicular/ is found to depend upon the central-cell potential phi approximately as tau/sub perpendicular/(msec) = 3phi(kV)/sup -2/. The transport rate, deduced from the data, agrees to within a factor of 1--5 with resonant-transport theory applied to the measured plasma parameters. Attempts to include radial effects by modeling the plasma self-consistently using resonant transport are less successful; near the axis the transport coefficients become too small to explain the equilibrium. Modeling using an ad hoc phi/sup -2/ law for the transport coefficients is more successful.

Hooper E.B. Jr.; Cohen, R.H.; Correll, D.L.; Gilmore, J.M.; Grubb, D.P.

1985-12-01

324

Acoustics and Surface Pressure Measurements from Tandem Cylinder Configurations  

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

325

Design and testing of a tandem row pump inducer  

NASA Technical Reports Server (NTRS)

The design and testing of a tandem row pump inducer having a supercavitating first stage with a 0.60 hub ratio is presented. The second stage tested was a helical impeller with a 0.70 hub ratio. A cubic arc transition was utilized to accomplish the hub change. The first stage had two blades and the free-vortex design approach was empirically modified based on previous experience. The recommended second stage design having four blades and using cambered blade section is presented but the model was not built or tested. The more simple helix was built instead to reduce cost. Data taken included head generation, cavitation observations and unsteady head fluctuations over the 0-100Hz range.

Etter, R. J.

1974-01-01

326

Sulphur hexafluoride as a stripper gas for tandem accelerators  

NASA Astrophysics Data System (ADS)

We have investigated sulphur hexafluoride as a stripper gas in tandem accelerators by using the ANTARES accelerator system at ANSTO to measure charge state distributions for this gas. Results are reported at 4 MV terminal voltage for injected negative ions ranging from carbon to uranium oxide. For iodine and thorium the distributions are extended across a range of energies of practical use for accelerator mass spectrometry, ion beam analysis and other accelerator applications. Charge state distributions using sulphur hexafluoride are found to have mean charge states up to 1 charge unit higher than, and to be broader than, corresponding distributions for argon gas, except in the case of carbon beams. As a result, SF6 is shown to provide significantly higher yields for charge states of heavy ions above the mean charge state. We now perform actinide AMS measurements with 9% yield to the 5+ charge state, compared to 4-5% achieved previously with argon gas.

Hotchkis, M. A. C.; Child, D.; Fink, D.; Garton, D.; Levchenko, V.; Wilcken, K.

2013-05-01

327

A tandem mass spectrometric method for singlet oxygen measurement.  

PubMed

Singlet oxygen, a harmful reactive oxygen species, can be quantified with the substance 2,2,6,6-tetramethylpiperidine (TEMP) that reacts with singlet oxygen, forming a stable nitroxyl radical (TEMPO). TEMPO has earlier been quantified with electron paramagnetic resonance (EPR) spectroscopy. In this study, we designed an ultra-high-performance liquid chromatographic-tandem mass spectrometric (UHPLC-ESI-MS/MS) quantification method for TEMPO and showed that the method based on multiple reaction monitoring (MRM) can be used for the measurements of singlet oxygen from both nonbiological and biological samples. Results obtained with both UHPLC-ESI-MS/MS and EPR methods suggest that plant thylakoid membranes produce 3.7 × 10(-7) molecules of singlet oxygen per chlorophyll molecule in a second when illuminated with the photosynthetic photon flux density of 2000 ?mol m(-2 ) s(-1). PMID:24849296

Karonen, Maarit; Mattila, Heta; Huang, Ping; Mamedov, Fikret; Styring, Stenbjörn; Tyystjärvi, Esa

2014-01-01

328

Orbit averaged radial buildup code for tandem mirror geometry  

SciTech Connect

The radial Fokker-Planck (RFP) model of A. Futch was modified to treat plasma buildup in the tandem mirror plug and center cell with a self-consistent model (TOARBUC). Two major changes have been made to the original version of this code. First, the center cell is treated as having separate electron and ion confining potentials with the ion potential having the opposite sign of that in a conventional mirror. Second, a two-electron-temperature treatment derived by R. Cohen was included in the present model to allow the plug and center cell to have different T/sub e/'s as observed in the experiment. The following sections explain these changes in greater detail.

Campbell, M.; Futch, A.H.

1981-01-22

329

Internal solitary wave propagation observed by tandem satellites  

NASA Astrophysics Data System (ADS)

Internal solitary waves (ISWs) are observed 2 times within 30 min in synthetic aperture radar (SAR) image pairs from the Envisat and ERS-2 tandem satellites. Three pairs of SAR images were acquired in the South China Sea (SCS) in April 2007, August 2008, and March 2009, and 13 ISWs were tracked between the image pair in an ArcGIS environment. The phase speeds of these ISWs are calculated from their spatial displacement and time interval. The resultant ISW speeds agree well with the theoretical values estimated from the Sturm-Louisville equation using local bathymetric and monthly climatology ocean stratification data. This technique reveals the spatial variation in the ISWs speed in the water depth between 100 and 4000 m in the SCS. The study shows that ISWs speed is mainly affected by bottom topography and generally decreases from deep to shallow water from east to west and from south to north.

Liu, Bingqing; Yang, Hong; Zhao, Zhongxiang; Li, Xiaofeng

2014-03-01

330

Activities of the Tandem Accelerator Center, University of Tsukuba  

NASA Astrophysics Data System (ADS)

This annual report includes the research activities and the technical developments carried out at the Tandem Accelerator Center in University of Tsukuba for the period from April 1992 to March 1993. New experimental investigations were made on (1) nuclear spectroscopy was initiated by a new (gamma) ray spectrometer; (2) polarization phenomena in nuclear reactions; (3) the application of energetic heavy ions to solid state physics; (4) the behavior of self interstitial atoms and its migration mechanism in Mo metal; (5) the studies on electronic conduction of metal oxides and bronzes by NMR; (6) Moessbauer studies on Fe-Cr alloy and the RBS analysis of YBCO superconductor films; and (7) a new field was challenged on the micro cluster physics. Nuclear collective motion and the relativistic mean-field theory is also included in this report.

1993-10-01

331

Configuration and layout of the tandem mirror Fusion Power Demonstrator  

SciTech Connect

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.

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

1983-11-30

332

Structural Basis of Actin Filament Nucleation by Tandem W Domains  

PubMed Central

SUMMARY Spontaneous nucleation of actin is very inefficient in cells. To overcome this barrier, cells have evolved a set of actin filament nucleators to promote rapid nucleation and polymerization in response to specific stimuli. However, the molecular mechanism of actin nucleation remains poorly understood. This is hindered largely by the fact that actin nucleus, once formed, rapidly polymerizes into filament, thus making it impossible to capture stable multisubunit actin nucleus. Here, we report an effective double-mutant strategy to stabilize actin nucleus by preventing further polymerization. Employing this strategy, we solved the crystal structure of AMPPNP-actin in complex with the first two tandem W domains of Cordon-bleu (Cobl), a potent actin filament nucleator. Further sequence comparison and functional studies suggest that the nucleation mechanism of Cobl is probably shared by the p53 cofactor JMY, but not Spire. Moreover, the double-mutant strategy opens the way for atomic mechanistic study of actin nucleation and polymerization. PMID:23727244

Chen, Xiaorui; Ni, Fengyun; Tian, Xia; Kondrashkina, Elena; Wang, Qinghua; Ma, Jianpeng

2013-01-01

333

Structural Characterization of Carbohydrates by Fourier Transform Tandem Mass Spectrometry  

PubMed Central

Fourier transform tandem mass spectrometry (MS/MS) provides high mass accuracy, high sensitivity, and analytical versatility and has therefore emerged as an indispensable tool for structural elucidation of biomolecules. Glycosylation is one of the most common posttranslational modifications, occurring in ~50% of proteins. However, due to the structural diversity of carbohydrates, arising from non-template driven biosynthesis, achievement of detailed structural insight is highly challenging. This review briefly discusses carbohydrate sample preparation and ionization methods, and highlights recent developments in alternative high-resolution MS/MS strategies, including infrared multiphoton dissociation (IRMPD), electron capture dissociation (ECD), and electron detachment dissociation (EDD), for carbohydrates with a focus on glycans and proteoglycans from mammalian glycoproteins. PMID:22389641

Zhou, Wen; Håkansson, Kristina

2012-01-01

334

Tandemly repeated tRNA pseudogenes in photobacterium.  

PubMed Central

A region distal to three tRNA genes in Photobacterium phosphoreum, a Gram-negative eubacterium, unexpectedly contains a high number of repeated DNA segments that are closely related to the adjacent tRNAPro gene. The 5' to 3' order of this cluster is tRNAPro-tRNAHis-tRNAPro followed by eight tRNAPro-like structures interspersed by rho-independent terminators. The two tRNAPro genes, which are identical, and the tRNAHis gene have 86% and 87% positional identity, respectively, to their counterparts in the argT operon of Escherichia coli. The facts that these tRNA-like structures are not transcribed, in contrast to the tRNA retropseudogenes of eukaryotes, and that these structures are clustered near their progenitor suggest they are an unusual class of tRNA pseudogenes that arose by tandem duplication. Images PMID:3194413

Giroux, S; Cedergren, R

1988-01-01

335

Assay for Glycosaminoglycans by Tandem Mass Spectrometry and its Applications  

PubMed Central

Glycosaminoglycans (GAGs) are distributed in the whole body and play a variety of important physiological roles associated with inflammation, growth, coagulation, fibrinolysis, lipolysis, and cell-matrix biology. Accumulation of undegraded GAGs in lysosomes gives rise to a distinct clinical syndrome, mucopolysaccharidoses. Measurement of each specific GAG in a variety of specimens is urgently required to understand GAG interaction with other molecules, physiological status of patients, and prognosis and pathogenesis of the disease. We established a highly sensitive and accurate tandem mass spectrometry (LC-MS/MS) method for measurements of disaccharides derived from four specific GAGs [dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and chondroitin sulfate (CS)]. Disaccharides were produced by specific enzyme digestion of each GAG, and quantified by negative ion mode of multiple reaction monitoring. Subclasses of HS and GAGs with identical molecular weights can be separated using a Hypercarbcolumn (2.0 mm×50 mm, 5 ?m) with an aectonitrile gradient in ammonium acetate (pH 11.0). We also developed a GAG assay by RapidFire with tandem mass spectrometry (RF-MS/MS). The RF system consists of an integrated solid phase extraction robot that binds and de-salts samples from assay plates and directly injects them into a MS/MS detector, reducing sample processing time to ten seconds. RF-MS/MS consequently yields much faster throughput than conventional LC-MS/MS-based methods. However, the RF system does not have a chromatographic step, and therefore, cannot distinguish GAGs that have identical molecular weights. Both methods can be applied to analysis of dried blood spots, blood, and urine specimens. In this article, we compare the assay methods for GAGs and describe their potential applications. PMID:25068074

Tomatsu, Shunji; Shimada, Tsutomu; Mason, Robert W; Kelly, Joan; LaMarr, William A; Yasuda, Eriko; Shibata, Yuniko; Futatsumori, Hideyuki; Montaño, Adriana M; Yamaguchi, Seiji; Suzuki, Yasuyuki; Orii, Tadao

2014-01-01

336

Multi-functional MBIT for peptide tandem mass spectrometry.  

PubMed

Isobaric tags have been widely used for the identification and quantification of proteins in mass spectrometry-based proteomics. The mass-balanced, (1) H/(2) H isotope-coded dipeptide tag (MBIT) is a multifunctional isobaric tag based on N-acetyl-Ala-Ala dipeptide containing an amine-reactive linker that conjugates the tag to the primary amines of proteolytic peptides. MBITs provide a pair of isotope-coded quantitation signals separated by 3?Da, which enables 2-plex quantification and identification of proteins in the 15-250?fmol range. Various MBITs diversified at the N-acetyl group or at the side chain of the first alanine provide a pair of bs ions as low-mass quantitation signals in a distinct mass window. Thus, a combination of different MBITs allows multiplex quantification of proteins in a single liquid chromatography-mass spectrometry experiment. Unlike other isobaric tags, MBITs also offer a pair of ys ions as high-mass quantitation signals in a noise-free region, facilitating protein quantification in quadrupole ion trap mass spectrometers. Uniquely, bS ions, forming N-protonated oxazolone, undergo unimolecular dissociation and generate the secondary low-mass quantitation signals, aS ions. The yield of aS ions derived from bS ions can be used to measure the temperature of bS ions, which enables a reproducible acquisition of the peptide tandem mass spectra. Thus, MBITs enable multiplexed quantitation of proteins and the concurrent measurement of ion temperature using bS and aS signal ions as well as the isobaric protein quantitation in resonance-type ion trap using yS (complement of bS ) signal ions. This review provides an overview of MBITs with a focus on the multi-functionality that has been successfully demonstrated in the peptide tandem mass spectrometry. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 34: 209-218, 2015. PMID:24872020

Yoon, Hye-Joo; Seo, Jongcheol; Shin, Seung Koo

2015-04-01

337

Digital Subtraction Fluoroscopic System With Tandem Video Processing Units  

NASA Astrophysics Data System (ADS)

A real-time digital fluoroscopic system utilizing two video processing units (Quantex) in tandem to produce continuous subtraction images of peripheral and internal vessels following intravenous contrast media injection has been inves-tigated. The first processor subtracts a mask image consisting of an exponentially weighted moving average of N1 frames (N1 = 2k where k = 0.7) from each incoming video frame, divides by N1, and outputs the resulting difference image to the second processor. The second unit continuously averages N2 incoming frames (N2 = 2k) and outputs to a video monitor and analog disc recorder. The contrast of the subtracted images can be manipulated by changing gain or by a non-linear output transform. After initial equipment adjustments, a subtraction sequence can be produced without operator interaction with the processors. Alternatively, the operator can freeze the mask and/or the subtracted output image at any time during the sequence. Raw data is preserved on a wide band video tape recorder permitting retrospective viewing of an injection sequence with different processor settings. The advantage of the tandem arrangement is that it has great flexibility in varying the duration and the time of both the mask and injection images thereby minimizing problems of registration between them. In addition, image noise is reduced by compiling video frames rather than by using a large radiation dose for a single frame, which requires a wide dynamic range video camera riot commonly available in diagnostic x-ray equipment. High quality subtraction images of arteries have been obtained in 15 anesthetized dogs using relatively low exposure rates (10-12 ?R/video frame) modest volumes of contrast medium (0.5-1 ml/kg), and low injection flow rates (6-10 ml/sec). The results/ achieved so far suggest that this system has direct clinical applications.

Gould, Robert G.; Lipton, Martin J.; Mengers, Paul; Dahlberg, Roger

1981-07-01

338

The Evolution of Tandemly Repetitive DNA: Recombination Rules  

PubMed Central

Variable numbers of tandem repeats (VNTRs), which include hypervariable regions, minisatellites and microsatellites, can be assigned together with satellite DNAs to define a class of noncoding tandemly repetitive DNA (TR-DNA). The evolution of TR-DNA is assumed to be driven by an unbiased recombinational process. A simulation model of unequal exchange is presented and used to investigate the evolutionary persistence of single TR-DNA lineages. Three different recombination rules are specified to govern the expansion and contraction of a TR-DNA lineage from an initial array of two repeats to, finally, a single repeat allele, which cannot participate in a misalignment and exchange process. In the absence of amplification or selection acting to bias array evolution toward expansion, the probability of attaining a target array size is a function only of the initial number of repeats. We show that the proportions of lineages attaining a targeted array size are the same irrespective of recombination rule and rate, demonstrating that our simulation model is well behaved. The time taken to attain a target array size, the persistence of the target array, and the total persistence time of repetitive array structure, are functions of the initial number of repeats, the rate of recombination, and the rules of misalignment preceding recombinational exchange. These relationships are investigated using our simulation model. While misalignment contraint is probably greatest for satellite DNA it also seems important in accounting for the evolution of VNTR loci including minisatellites. This conclusion is consistent with the observed nonrandom distributions of VNTRs and other TR-DNAs in the human genome. PMID:1468634

Harding, R. M.; Boyce, A. J.; Clegg, J. B.

1992-01-01

339

Radical-driven peptide backbone dissociation tandem mass spectrometry.  

PubMed

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. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 34: 116-132, 2015. PMID:24863492

Oh, Han Bin; Moon, Bongjin

2015-04-01

340

Lightweight tandem GaAs\\/CuInSe2 solar cells  

Microsoft Academic Search

High-efficiency, ultralightweight, mechanically stacked 4-cm2 thin-film tandem solar cells are discussed. The tandem stack consists of a single-crystal, thin-film Ga(Al)As cell fabricated by the cleavage of lateral epitaxy for transfer (CLEFT) process and adhesively bonded to the top of a CdZnS\\/CuInSe2 polycrystalline thin-film cell deposited on glass. Maximum tandem efficiency in a four-terminal configuration of 21.6% AM0 have been demonstrated.

B. J. Stanbery; B. D. King; R. M. Burgess; R. W. McClelland; N. P. Kim; R. P. Gale; R. A. Mickelsen

1990-01-01

341

Pulsating Tandem Microbubble for Localized and Directional Single-Cell Membrane Poration  

NASA Astrophysics Data System (ADS)

The interaction of laser-generated tandem microbubble (maximum diameter of about 50?m) with single (rat mammary carcinoma) cells is investigated in a 25-?m liquid layer. Antiphase and coupled oscillation of the tandem microbubble leads to the formation of alternating, directional microjets (with max microstreaming velocity of 10m/s) and vortices (max vorticity of 350000s-1) in opposite directions. Localized and directional membrane poration (200 nm to 2?m in pore size) can be produced by the tandem microbubble in an orientation and proximity-dependent manner, which is absent from a single oscillating microbubble of comparable size and at the same stand-off distance.

Sankin, G. N.; Yuan, F.; Zhong, P.

2010-08-01

342

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

343

Expansion of stochastic expression repertoire by tandem duplication in mouse Protocadherin-? cluster  

PubMed Central

Tandem duplications are concentrated within the Pcdh cluster throughout vertebrate evolution and as copy number variations (CNVs) in human populations, but the effects of tandem duplication in the Pcdh cluster remain elusive. To investigate the effects of tandem duplication in the Pcdh cluster, here we generated and analyzed a new line of the Pcdh cluster mutant mice. In the mutant allele, a 218-kb region containing the Pcdh-?2 to Pcdh-?c2 variable exons with their promoters was duplicated and the individual duplicated Pcdh isoforms can be disctinguished. The individual duplicated Pcdh-? isoforms showed diverse expression level with stochastic expression manner, even though those have an identical promoter sequence. Interestingly, the 5?-located duplicated Pcdh-?c2, which is constitutively expressed in the wild-type brain, shifted to stochastic expression accompanied by increased DNA methylation. These results demonstrate that tandem duplication in the Pcdh cluster expands the stochastic expression repertoire irrespective of sequence divergence. PMID:25179445

Kaneko, Ryosuke; Abe, Manabu; Hirabayashi, Takahiro; Uchimura, Arikuni; Sakimura, Kenji; Yanagawa, Yuchio; Yagi, Takeshi

2014-01-01

344

A Dynamic Programming Approach to De Novo Peptide Sequencing via Tandem Mass Spectrometry  

E-print Network

A Dynamic Programming Approach to De Novo Peptide Sequencing via Tandem Mass Spectrometry Ting Chen(|V ||E|) time and O(|V |2 ) space using dynamic programming. For an ideal noise-free spectrum with only b

Chen, Ting

345

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

SciTech Connect

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)

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

1981-01-21

346

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....

347

Analyzing Forced Unfolding of Protein Tandems by Ordered Variates, 2: Dependent Unfolding Times  

E-print Network

to the development of new kinetic models, which describe the probabilities of ordered unfolding transitions rather of protein domains in a tandem or a polyprotein are analyzed by ap- plying constant mechanical force (force

Barsegov, Valeri

348

Progress in radiocarbon dating with the Chalk River MP tandem accelerator  

SciTech Connect

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.

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

1980-01-01

349

Room temperature tandem hydroamination and hydrosilation/protodesilation catalysis by a tricarbonylchromium-bound iridacycle.  

PubMed

A chromiumtricarbonyl-bound iridacycle displays novel catalytic virtues for the conversion of terminal aromatic alkynes into racemic N-phenyl, 1-arylethylamines by tandem hydro-amination and hydrosilation/protodesilation reactions under mild "one pot" conditions. PMID:22982813

Iali, Wissam; La Paglia, Frédéric; Le Goff, Xavier-Frédéric; Sredojevi?, Dušan; Pfeffer, Michel; Djukic, Jean-Pierre

2012-10-25

350

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

E-print Network

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 ...

Mak, Xiao Yin

2008-01-01

351

Analogy between MSE estimation theory and information theory in the study of tandem communication links  

E-print Network

This research deals with developing an analogy between concepts in information theory and estimation theory in tandem communication problems. The analogy proposed by Messerschmitt [1] provides the intuitive basis for establishing a correspondence...

Piard, Veronique D.

1994-01-01

352

Tandem polymer solar cells featuring a spectrally matched low-bandgap polymer  

NASA Astrophysics Data System (ADS)

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, ~1.44 eV). A single-layer device based on the polymer provides a power conversion efficiency of ~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.

Dou, Letian; You, Jingbi; Yang, Jun; Chen, Chun-Chao; He, Youjun; Murase, Seiichiro; Moriarty, Tom; Emery, Keith; Li, Gang; Yang, Yang

2012-03-01

353

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

E-print Network

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 ...

Mamaliga, Galina

2012-01-01

354

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...

355

Tandem quadrupole Fourier-transform mass spectrometry of oligopeptides and small proteins.  

PubMed Central

Modifications to the newly developed tandem quadrupole Fourier-transform mass spectrometer have made it possible to record mass spectra on oligopeptides and small proteins in the mass range between 2 and 13 kDa. PMID:3468502

Hunt, D F; Shabanowitz, J; Yates, J R; Zhu, N Z; Russell, D H; Castro, M E

1987-01-01

356

The tandem inverter: combining the advantages of voltage-source and current-source inverters  

Microsoft Academic Search

A combination of a current-source primary inverter and a voltage-source secondary inverter is proposed as the so-called tandem inverter. The primary inverter operates in the square-wave mode, handling most of the converted power, while its output harmonic currents are compensated by the much smaller secondary inverter. As a result, the tandem inverter, to be used for AC motor control, combines

A. M. Trznadlowski; F. Blaabjerg; J. K. Pedersen; N. Patriciu

1998-01-01

357

Application of Tandem Techniques with Contact Mono-Elements or Phased Array Probes: Simulation and Experiments  

NASA Astrophysics Data System (ADS)

Ultrasonic tandem inspection techniques are widely used to detect midwall defects. Conventionally, a pair of probes scans the specimen, one transducer at transmission, one at reception. An alternative application relies on the selection of different elements over an array, some at transmission, others at reception. Simulation tools for tandem inspection have been integrated into the Civa software developed at CEA, with support from EWI. This paper presents some simulation examples for contact monolithic and phased arrays probes.

Raillon, R.; Lozev, M.; Spencer, R.; Kerbrat, E.; Mahaut, S.

2005-04-01

358

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

SciTech Connect

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.

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

1983-08-12

359

BRCA1 interacts with acetylCoA carboxylase through its tandem of BRCT domains  

Microsoft Academic Search

Germ-line alterations in BRCA1 are associated with an increased susceptibility to breast and ovarian cancer. BRCA1 is a 220-kDa protein that contains a tandem of two BRCA1 C-Terminal (BRCT) domains. Among missense and nonsense BRCA1 mutations responsible for family breast cancer, some are located into the BRCT tandem of BRCA1 coding sequence. In an attempt to understand how BRCT is

Clémence Magnard; Richard Bachelier; Anne Vincent; Michel Jaquinod; Sylvie Kieffer; Gilbert M Lenoir; Nicole Dalla Venezia

2002-01-01

360

Tandem mass spectrometer for the detection of nitroaromatic compounds and other electronegative species in ambient air  

NASA Astrophysics Data System (ADS)

A tandem mass spectrometer has been constructed consisting of a quadrupole mass filter followed by a time-of-flight mass spectrometer. Ions are generated in an atmospheric pressure ionization (API) source, which allows for detection of certain types of compounds in ambient air. The combination of API with this tandem mass spectrometer offers the potential to do real-time monitoring of targeted compounds that are of environmental and other concern.

Glish, G. L.; McLuckey, S. A.; McKown, H. S.

361

Hot-Electron Plasma Formation and Confinement in the Tandem Mirror Experiment-Upgrade  

Microsoft Academic Search

Electron-Cyclotron range-of-frequency heating (ECRH) at 28 GHz is used to create a population of mirror -confined hot electrons in the Tandem Mirror Experiment -Upgrade (TMX-U). Generation of a large fraction of such electrons within each end-cell of TMX-U is essential to the formation of the desired electrostatic potential profile of the thermal-barrier tandem mirror. The formation and confinement of the

David Bruce Ress

1988-01-01

362

Structural determination by atmospheric pressure photoionization tandem mass spectrometry of some compounds isolated from the SARA fractions obtained from bitumen.  

PubMed

We have identified compounds obtained from the SARA fractions of bitumen by using atmospheric pressure photoionization mass spectrometry and low-energy collision tandem mass spectrometric analyses with a QqToF-MS/MS hybrid instrument. The identified compounds were isolated from the maltene saturated oil and the aromatic fractions of the SARA components of a bitumen. The QqToF instrument had sufficient mass resolution to provide accurate molecular weight information and to enhance the tandem mass spectrometry results. The APPI-QqToF-MS analysis of the separated compounds showed a series of protonated molecules [M + H](+) and molecular ions [M](+?) of the same mass but having different chemical structures, in the maltene saturated oil and the aromatic SARA fractions. These isobaric ions were a molecular ion [M2 ](+?) at m/z 418.2787 and a protonated molecule [M5 + H](+) at m/z 287.1625 in the saturated oil fraction, and molecular ions [M6 ](+?) at m/z 418.1584 and [M7 ](+?) at m/z 287.1285 in the aromatic fraction. The identification of this series of chemical compounds was achieved by performing CID-MS/MS analyses of the molecular ions [M](+?) ([M1 ](+?) at m/z 446. 2980, [M2 ](+?) at m/z 418.2787, [M3 ](+?) at m/z 360.3350 and [M4 ](+?) at m/z 346.2095) in the saturated oil fraction and of the [M5 + H](+) ion at m/z 287.1625 also in the saturated oil fraction. The observed CID-MS/MS fragmentation differences were explained by proposed different breakdown processes of the precursor ions. The presented tandem mass spectrometric study shows the capability of MS/MS experiments to differentiate between different classes of chemical compounds of the SARA components of bitumen and to explain the reasons for the observed mass spectrometric differences. However, greater mass resolution than that provided by the QqToF-MS/MS instrument would be required for the analysis of the asphaltene fraction of bitumen. PMID:23657961

Tachon, Nadine; Jahouh, Farid; Delmas, Michel; Banoub, Joseph H

2011-09-30

363

The Electron Power Balance in the Tandem Mirror Phaedrus.  

NASA Astrophysics Data System (ADS)

Measurements have been taken of a plasma in the tandem mirror Phaedrus, sustained and heated by RF alone (RF sustained mode), to determine the dominant terms in an electron power balance equation. The ultimate aim of understanding the electron power balance is to determine ways to raise the electron temperaure T(,e), an important step in improving the performance of the tandem mirror. The results of this study are presented in this thesis. The RF sustained plasma is maintained by RF in the end plugs at (omega)(,ci), and by gas puffing and RF at (omega) < (omega)(,ci) in the central cell. The result is a quasi-steady-state plasma lasting (TURN) 8 msec in this study. Typically, the plasma in both end plugs and central cell have T(,e) (TURN) 19 (+OR-) 3 eV, with peak densities of (TURN) 2 x 10('12) cm('-3) throughout. The central cell confining potential (phi)(,c) is near zero for this plasma. Along the plasma axis, the electron power input is from Coulomb drag off of the hotter ions ((TURN) 30%), from direct heating by the plug RF ((TURN) 30%) and by the central cell RF ((TURN) 40%). The power losses are dominated by the convective loss of the electrons to the end walls, amounting to (TURN) 80 to 90% of the total, with the remaining losses due to the ionization of and excitation radiation from neutral molecular and atomic hydrogen. When the plasma within a 1/e radius flux tube is examined, the power losses due to neutral gases becomes larger, particularly from the molecular species. The amount of power lost by neutral gases, however, cannot accurately be determined due to uncertainties in the molecular hydrogen density profile. Finally, by dividing the total electron energy content by the total electron power input, a value for the electron energy confinement time can be determined. On axis, a value of 160 (+OR-) 40 (mu)sec is obtained. The Pastukhov value is. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). on axis, and. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). at a radius of 7.4 cm.

Yujiri, Larry

1982-11-01

364

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

SciTech Connect

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.

Schuermann, Karl; Vorwerk, Dierk; Buecker, Arno; Grosskortenhaus, Stefanie; Guenther, Rolf W. [Department of Diagnostic Radiology, University of Technology, Pauwelsstrasse 30, D-52057 Aachen (Germany)

1998-09-15

365

Exploring the intention of using aspirated cascade to replace tandem cascades  

NASA Astrophysics Data System (ADS)

In the present paper, computational fluid dynamics (CFD) simulations were executed to exploring the intent of using aspirated cascade to replace tandem cascades. Firstly, the ONERA tandem cascades were investigated, and the performance of the cascades at the design point were listed, such as diffusion factor, total pressure loss coefficient, deviation angle etc. For replacing the ONERA tandem cascades, a new cascade was designed with the codes BLADEGEN developed by the authors. The quasi 3-D calculations were carried out using the collection of programs for cascade analysis and design, MISES. The cascade was analyzed and designed by using this code. And the cascade was simulated and analyzed by commercial CFD software. It is found there is an obvious separation on the suction side. Based on the 3D CFD simulation results of the cascade without aspiration, an aspirated cascade was designed by introducing a slot on the suction side. The performance of the aspirated cascade was investigated and compared with the tandem cascades, indicated that under the same inlet condition, the total pressure loss of the single row aspirated cascade was less than that of the tandem cascades, and the outlet static pressure is higher than that of the tandem cascades. Meanwhile, the different suction slot location, suction width and suction mass flow are studied for the aspirated cascade.

Zhao, Shengfeng; Luo, Jianfeng; Lu, Xingen; Zhu, Junqiang

2010-10-01

366

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

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

367

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

PubMed

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

Ruff, Karen M; Strobel, Scott A

2014-11-01

368

Rapid assessment of the coenzyme Q10 redox state using ultrahigh performance liquid chromatography tandem mass spectrometry.  

PubMed

An improved method for accurate and rapid assessment of the coenzyme Q10 (CoQ10) redox state using ultrahigh performance liquid chromatography tandem mass spectrometry was described, with particular attention given to the instability of the reduced form of CoQ10 during sample preparation, chromatographic separation and mass spectrometric detection. As highly lipophilic compounds in complex biological matrices, both reduced and oxidized forms of CoQ10 were extracted simultaneously from the tissue samples by methanol which is superior to ethanol and isopropanol. After centrifugation, the supernatants were immediately separated on a C18 column with isocratic elution using methanol containing 2 mM ammonium acetate as a non-aqueous mobile phase, and detected by positive electrospray ionization tandem mass spectrometry in multiple reaction monitoring (MRM) mode. Ammonium acetate as an additive in methanol provided enhanced mass spectrometric responses for both forms of CoQ10, primarily due to stable formation of adduct ions [M + NH4](+), which served as precursor ions in positive ionization MRM transitions. The assay showed a linear range of 8.6-8585 ng mL(-1) for CoQ10H2 and 8.6-4292 ng mL(-1) for CoQ10. The limits of detection (LODs) were 7.0 and 1.0 ng mL(-1) and limits of quantification (LOQs) were 15.0 and 5.0 ng mL(-1) for CoQ10H2 and CoQ10, respectively. This rapid extractive and analytical method could avoid artificial auto-oxidation of the reduced form of CoQ10, enabling the native redox state assessment. This reliable method was also successfully applied for the measurement of the CoQ10 redox state in liver tissues of mice exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin, revealing the down-regulated mitochondrial electron transport chain. PMID:25140668

Tang, Zhi; Li, Shangfu; Guan, Xinyuan; Schmitt-Kopplin, Philippe; Lin, Shuhai; Cai, Zongwei

2014-11-01

369

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

NASA Astrophysics Data System (ADS)

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.

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

370

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

PubMed Central

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

2014-01-01

371

Detection of stanozolol in environmental waters using liquid chromatography tandem mass spectrometry  

PubMed Central

Background Owing to frequent administration of a wide range of pharmaceutical products, various environmental waters have been found to be contaminated with pharmacologically active substances. For example, stanozolol, a synthetic anabolic steroid, is frequently misused for performance enhancement as well as for illegal growth promoting purposes in veterinary practice. Previously we reported stanozolol in hair samples collected from subjects living in Budapest. For this reason we initiated this study to explore possible environmental sources of steroid contamination. The aim of this study was to develop a method to monitor stanozolol in aqueous matrices using liquid chromatography tandem mass spectrometry (LC-MS/MS). Results Liquid-liquid extraction using pentane was found to be an efficient method for the extraction of stanozolol from water samples. This was followed by direct detection using LC-MS/MS. The method was capable of detecting 0.25 pg/mL stanozolol when only 5 mL water was processed in the presence of stanozolol D3 as internal standard. Fifteen bottled waters analysed were found to be negative for stanozolol. However, three out of six samples from the Danube river, collected from December '09 to November '10, were found to contain stanozolol at concentrations up to 1.82 pg/mL. In contrast, only one sample (out of six) of urban tap water from Budapest city was found to contain stanozolol, at a concentration of 1.19 pg/mL. Conclusion The method developed is efficient, rapid, reproducible, sensitive and robust for the detection of stanozolol in aqueous matrices. PMID:21999747

2011-01-01

372

Multilocus variable number tandem repeat analysis for Salmonella enterica subspecies.  

PubMed

Genomic analysis of Salmonella enterica revealed the existence of a variable number of tandem repeats (VNTR) at multiple loci. Some S. enterica strains are considered as references (Typhi Ty2, Typhi CT18, Typhimurium LT2, Enteritidis LK5, PT4, and Enteritidis 07-2642, and Newport). These allowed the selection of markers to develop the genotyping technique, multiple-locus VNTR analysis (MLVA). These markers were used to discriminate S. enterica isolated from humans, food, or the environment. In this report, the characteristics and specifications of 58 salmonella markers described from 2003 to 2009 are analyzed. Some VNTR loci were used as markers. The markers were used to discriminate S. enterica isolates from different sources and geographical localizations. Among the VNTR loci described in the published reports, eight presented with a high diversity index (DI) of polymorphism of more than 0.80. The selection of several markers within a single locus validated their polymorphism characteristic. Despite unequal DI values, the use of a panel of markers is a powerful discriminatory tool for the surveillance and identification of the source of salmonella outbreak. Depending on the markers selected, MLVA should be used either for macro- or microepidemiological purposes. The main challenge in the future for this technique is standardization. PMID:21153561

Kruy, S L; van Cuyck, H; Koeck, J L

2011-04-01

373

Mechanical design of the Tandem Mirror Experiment Upgrade vacuum system  

SciTech Connect

The Tandem Mirror Experiment Upgrade (TMX Upgrade) vacuum system uses most of the vacuum system from the original TMX and substantially increases its capabilities. The vacuum system provides the main structure for the experimental apparatus, as well as providing and maintaining the vacuum environment. The vacuum vessel provides the structure supporting all magnets, as they are contained inside the vacuum vessel, all of the neutral-beam injectors, and the various diagnostics. The vessel provides the main vacuum enclosure and the various access ports required by the magnet system, injector system, internal vacuum system, and plasma diagnostics. The vacuum environment is created and maintained by two systems, the external vacuum system and the internal vacuum system. The external system consists of mechanical pumps, turbopumps, and cryopumps, and creates a vacuum inside the vessel down to a minimum pressure of 10/sup -6/ Torr. The internal vacuum system further reduces the pressure into the 10/sup -8/ Torr range and provides the fast pumping required to handle the excess gas from the neutral-beam injector system during a plasma shot. The internal vacuum system consists of titanium sublimators and liquid nitrogen (LN) liners that separate the vacuum vessel into various pumping regions.

Lang, D.D.; Calderon, M.O.; Thomas, S.R.; Garner, D.R.

1981-09-24

374

Instability at Short Tandem Repeats in Lymphoblastoid Cell Lines  

PubMed Central

Objectives Epstein Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) are a useful biological resource, however, genomic variations can happen during the generation and immortalization processes of LCLs. The purpose of this study was to identify genomic variations in LCL DNA compared with matched blood DNA using short tandem repeats (STRs) analysis. Methods We analyzed 15 STRs with blood DNA and their matched LCL DNA samples from 6645 unrelated healthy individuals. Results Mutations (such as repeat variations and triallelic patterns) of 15 STR loci were detected in 612 LCL DNAs (9.2% of total) without mutations in their matched blood DNA. The repeat variations of 15 STRs were detected in 526 LCL DNAs (mutation rate = 0.0792) and triallelic patterns were identified in 123 (mutation rate = 0.0185). Among 15 STRs, the most common repeat variations (n = 214, mutation rate = 0.0322) and triallelic patterns (n = 17, mutation rate = 0.0026) were found at FGA locus. Conclusion Our study shows that mutations in STRs can occur during generation and immortalization of LCLs. PMID:24159555

Lee, Jae-Eun; Hong, Eun-Jung; Kim, Ji-Hyun; Shin, So Youn; Kim, Young-Youl; Han, Bok-Ghee

2013-01-01

375

Decision Tree-Driven Tandem Mass Spectrometry for Shotgun Proteomics  

PubMed Central

Mass spectrometry (MS) has become a key technology for modern large-scale protein sequencing. Tandem MS (MS/MS) — the process of peptide ion dissociation followed by mass-to-charge (m/z) analysis — is the critical component of MS approaches. Recent advances in mass spectrometry now permit two discrete, and complementary, types of peptide ion fragmentation — collision-activated dissociation (CAD) and electron transfer dissociation (ETD) on a single instrument. To exploit this complementarity and increase sequencing success rates, we designed and embedded a data dependent-decision tree algorithm (DT) to make unsupervised, real-time decisions of which fragmentation method to employ based on precursor charge (z) and m/z. Large-scale proteome analysis of Saccharomyces cerevisiae and human embryonic stem cells (hES) with the DT algorithm netted 53,055 peptide identifications — besting either CAD (38,293) or ETD (39,507) alone. That trend was maintained upon application of the DT method to phosphoproteomics, yielding 7,422 vs. either 2,801 (CAD) or 5,874 (ETD) phosphopeptides. PMID:18931669

Swaney, Danielle L.; McAlister, Graeme C.; Coon, Joshua J.

2008-01-01

376

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

SciTech Connect

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.

Collins, D

2010-06-18

377

Modeling tandem AAG8-MEK inhibition in melanoma cells.  

PubMed

Drug resistance presents a challenge to the treatment of cancer patients, especially for melanomas, most of which are caused by the hyperactivation of MAPK signaling pathway. Innate or acquired drug-resistant relapse calls for the investigation of the resistant mechanisms and new anti-cancer drugs to provide implications for the ultimate goal of curative therapy. Aging-associated gene 8 (AAG8, encoded by the SIGMAR1 gene) is a chaperone protein profoundly elaborated in neurology. However, roles of AAG8 in carcinogenesis remain unclear. Herein, we discover AAG8 antagonists as new MEK inhibitors in melanoma cells and propose a novel drug combination strategy for melanoma therapy by presenting the experimental evidences. We report that specific antagonism of AAG8, efficiently suppresses melanoma cell growth and migration through, at least in part, the inactivation of the RAS-CRAF-MEK signaling pathway. We further demonstrate that melanoma cells that are resistant to AAG8 antagonist harbor refractory CRAF-MEK activity. MEK acts as a central mediator for anti-cancer effects and also for the resistance mechanism, leading to our proposal of tandem AAG8-MEK inhibition in melanoma cells. Combination of AAG8 antagonist and very low concentration of a MEK inhibitor synergistically restricts the growth of drug-resistant cells. These data collectively pinpoint AAG8 as a potential target and delineate a promising drug combination strategy for melanoma therapy. PMID:24634165

Sun, Bing; Kawahara, Masahiro; Nagamune, Teruyuki

2014-06-01

378

The 2 MV tandem pelletron accelerator of the Louvre Museum  

NASA Astrophysics Data System (ADS)

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.

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

1990-01-01

379

Measurements of Unsteady Wake Interference Between Tandem Cylinders  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

380

The evolution and function of protein tandem repeats in plants.  

PubMed

Sequence tandem repeats (TRs) are abundant in proteomes across all domains of life. For plants, little is known about their distribution or contribution to protein function. We exhaustively annotated TRs and studied the evolution of TR unit variations for all Ensembl plants. Using phylogenetic patterns of TR units, we detected conserved TRs with unit number and order preserved during evolution, and those TRs that have diverged via recent TR unit gains/losses. We correlated the mode of evolution of TRs to protein function. TR number was strongly correlated with proteome size, with about one-half of all TRs recognized as common protein domains. The majority of TRs have been highly conserved over long evolutionary distances, some since the separation of red algae and green plants c. 1.6 billion yr ago. Conversely, recurrent recent TR unit mutations were rare. Our results suggest that the first TRs by far predate the first plants, and that TR appearance is an ongoing process with similar rates across the plant kingdom. Interestingly, the few detected highly mutable TRs might provide a source of variation for rapid adaptation. In particular, such TRs are enriched in leucine-rich repeats (LRRs) commonly found in R genes, where TR unit gain/loss may facilitate resistance to emerging pathogens. PMID:25420631

Schaper, Elke; Anisimova, Maria

2015-04-01

381

ECRH and ICRH in the TMX-U tandem mirror  

SciTech Connect

In the Tandem Mirror Experiment Upgrade (TMX-U), the formation of a thermal barrier and the potential plugging of ion end loss were achieved at central-cell densities up to 2 x 10/sup 12/ cm/sup -3/. The presence of a thermal barrier was confirmed by direct measurement, and ion axial-confinement times in the range 50 to 100 ms were measured. The ECRH in the end cells (a) initiates plasma startup, (b) generates hot, mirror-confined electrons to form thermal barriers, and (c) creates the plugging potential for central-cell ions. The ECRH system consists of four 200 kW, 28 GHz gyrotrons each feeding power to a separate heating location (two in each end plug). Fundamental heating is used at the potential plug, and second harmonic is used in the thermal barrier. Hot-electron plasmas are produced at total end-cell antenna power levels up to 300 kW. Strong single-pass absorption and net hot-electron heating efficiencies exceeding 40% are observed. Hot-electron parameters achieved are: n/sub eh//n/sub et/ up to 0.8, volume-average beta <..beta..> approx. = 0.15, and T/sub x/ (x-ray tail above 40 keV) in the range 75 to 200 keV.

Stallard, B.W.; Cummins, W.F.; Molvik, A.W.; Poulsen, P.; Simonen, T.C.; Falabella, S.; Barter, J.D.; Christensen, T.; Dimonte, G.; Romesser, T.E.

1984-03-15

382

A tandem mirror hybrid plume plasma propulsion facility  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

383

Silicon wafer-based tandem cells: The ultimate photovoltaic solution?  

NASA Astrophysics Data System (ADS)

Recent large price reductions with wafer-based cells have increased the difficulty of dislodging silicon solar cell technology from its dominant market position. With market leaders expected to be manufacturing modules above 16% efficiency at 0.36/Watt by 2017, even the cost per unit area (60-70/m2) will be difficult for any thin-film photovoltaic technology to significantly undercut. This may make dislodgement likely only by appreciably higher energy conversion efficiency approaches. A silicon wafer-based cell able to capitalize on on-going cost reductions within the mainstream industry, but with an appreciably higher than present efficiency, might therefore provide the ultimate PV solution. With average selling prices of 156 mm quasi-square monocrystalline Si photovoltaic wafers recently approaching 1 (per wafer), wafers now provide clean, low cost templates for overgrowth of thin, wider bandgap high performance cells, nearly doubling silicon's ultimate efficiency potential. The range of possible Si-based tandem approaches is reviewed together with recent results and ultimate prospects.

Green, Martin A.

2014-03-01

384

Tandem self-powered photovoltaic-electrochromic window coatings  

SciTech Connect

Wide-gap, transparent amorphous silicon based photovoltaics can be integrated with electrochromic materials to produce a self-powered ``smart`` window coating. Existing electrochromic window designs external electrical connection, which may be economically unfeasible. This problem is solved by the tandem photovoltaic-electrochromic (PV/EC) device, in which a wide-gap amorphous silicon-based alloy (a-SiC:H) photovoltaic device is deposited together with an electrochromic optical transmittance modulator in a monolithic device on a single substrate. In this paper, the authors discuss their proposed monolithic photovoltaic-electrochromic device. They also present studies of transparent, wide-gap (Tauc gap of 1.8 to 2.2 eV) amorphous silicon-carbon thin films and p-i-n devices designed for use in the photovoltaic-electrochromic device. The photovoltaic cells in the PV-EC can operate at low current (<1 mA/cm{sup 2}) because a total injected charge of only 60 {micro}C/cm{sup 2} will darken the EC layer to a visible transmission of 5%, but they will need a high open-circuit voltage (>1.0 V) and high transparency ({approx}70%). They describe the progress toward these design targets.

Bullock, J.N.; Xu, Y.; Benson, D.K.; Branz, H.M. [National Renewable Energy Lab., Golden, CO (United States)

1995-12-31

385

Electrospray Ionization Tandem Mass Spectrometry of Ammonium Cationized Polyethers  

NASA Astrophysics Data System (ADS)

Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers.

Nasioudis, Andreas; Heeren, Ron M. A.; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F.

2011-05-01

386

Measurements of the Flowfield Interaction Between Tandem Cylinders  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

387

Flow past two tandem square cylinders vibrating transversely in phase  

NASA Astrophysics Data System (ADS)

Numerical investigations have been carried out to study the wake characteristics of flow past two tandem square cylinders vibrating in phase. Both the cylinders vibrate in a transverse direction, i.e., perpendicular to the incoming flow with the same frequency and amplitude. The frequency of vibration of the cylinders and the inter-cylinder spacing are varied for fixed values of the Reynolds number (Re = 100) and the amplitude ratio (A/D = 0.4). The synchronous or lock-in regime for the oscillatory wake of the vibrating cylinders has been identified by varying the frequency of the vibration from {{f}_{e}} = 0.4 {{f}_{0}} to 1.6 {{f}_{0}} ({{f}_{0}} being the frequency of vortex shedding behind a stationary square cylinder). The characteristics of lift and drag and the mechanism of vortex shedding are studied by varying the excitation frequency within the lock-in range for each value of inter-cylinder spacing. The complex interaction of flow between the cylinders gives rise to a variety of characteristically different shedding patterns in their wake. For values of inter-cylinder spacing equal to 2D and 3D, periodic, as well as quasi-periodic, lock-in behaviors are observed in the synchronous range.

Mithun, M. G.; Tiwari, Shaligram

2014-10-01

388

Extraction of Builidng Shape from Tandem-X Data  

NASA Astrophysics Data System (ADS)

Large scale mapping and modeling of urban areas is requested in many fields, especially in planning of energy supply and for change detection. For this purpose, SAR systems are highly attractive due to their independency of daytime and weather. The new satellite configuration of TerraSAR-X and TanDEM-X provides single-pass 3D mapping of the earth with unprecedented geometric resolution, allowing for improved detection and extraction of building positions and shapes. In this paper, single-pass interferograms of the TanDEM-X mission are utilized to automatically reconstruct buildings. To this purpose, first an interferogram is calculated from a TanDEM pair. Then, a new detector is applied that analyses phase ramps in the interferogram. Phase ramps being a pattern typically observable in layover areas of buildings, the detector is able to indicate building locations. Afterwards, the detected building areas are analyzed in more detail to extract width, length, and height of the buildings. Last, an edge detector is applied to deduce the building shapes. The reconstruction results are compared with reference data.

Thiele, A.; Wurth, M. M.; Even, M.; Hinz, S.

2013-05-01

389

Solvent extraction and tandem dechlorination for decontamination of soil.  

PubMed

The United States Environmental Protection Agency (US EPA) guidelines allow removal of polychlorinated biphenyls (PCBs) from soils via solvent extraction. This option holds promise for removal of other recalcitrant organic contaminants as well. A study was undertaken to evaluate the effectiveness of solvent extraction with two tandem degradation techniques. The degradation techniques were chemical dehalogenation with immobilized reagents and gamma-ray irradiation. The integrated approach was evaluated with contaminated soils from wood treatment and electric power substation sites. Evaluations were carried out on a bench scale in the laboratory and on a semi-pilot scale at a contaminated site. Binary solvent mixture of alkanes and alcohols yielded the highest extraction efficiencies. Extraction efficiencies in excess of 90% were obtained for PCBs, polychlorinated dibenzo-p-dioxins (PCDDs) and polynuclear aromatic hydrocarbons (PAHs). Extracted PCBs were rapidly degraded through chemical dehalogenation or with high doses of the gamma-ray irradiation. The residual organics in the solvent mixture were removed with activated carbon, and the solvent was recycled for subsequent soil extractions. Contaminants adsorbed on the activated carbon were destroyed with a counter flow oxidation process. PMID:11372830

Nam, P; Kapila, S; Liu, Q; Tumiatti, W; Porciani, A; Flanigan, V

2001-01-01

390

Tandem antioxidant enzymes confer synergistic protective responses in experimental filariasis.  

PubMed

Helminth parasites use antioxidant defence strategies for survival during oxidative stress due to free radicals in the host. Accordingly, tissue-dwelling filarial parasites counteract host responses by releasing a number of antioxidants. Targeting these redox regulation proteins together, would facilitate effective parasite clearance. Here, we report the combined effect of protective immune responses trigged by recombinant Wuchereria bancrofti thioredoxin (WbTRX) and thioredoxin peroxidase (WbTPX) in an experimental filarial model. The expression of WbTRX and WbTPX in different stages of the parasite and their cross-reactivity were analysed by enzyme-linked immunosorbent assay (ELISA). The immunogenicity of recombinant proteins and their protective efficacy were studied in animal models when immunized in single or cocktail mode. The antigens showed cross-reactive epitopes and induced high humoral and cellular immune responses in mice. Further, parasite challenge against Brugia malayi L3 larvae in Mastomys coucha conferred significant protection of 57% and 62% against WbTRX and WbTPX respectively. The efficacy of L3 clearance was significantly higher (71%) (P <  0.001) when the antigens were immunized together, showing a synergistic effect in multiple-mode vaccination. Hence, the study suggests WbTRX and WbTPX to be attractive vaccine candidates when immunized together and provides a tandem block for parasite elimination in the control of lymphatic filariasis. PMID:23676147

Prince, P R; Madhumathi, J; Anugraha, G; Jeyaprita, P J; Reddy, M V R; Kaliraj, P

2014-12-01

391

Sequence analysis of styrenic copolymers by tandem mass spectrometry.  

PubMed

Styrene and smaller molar amounts of either m-dimethylsilylstyrene (m-DMSS) or p-dimethylsilylstyrene (p-DMSS) were copolymerized under living anionic polymerization conditions, and the compositions, architectures, and sequences of the resulting copolymers were characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem mass spectrometry (MS(2)). MS analysis revealed that linear copolymer chains containing phenyl-Si(CH3)2H pendants were the major product for both DMSS comonomers. In addition, two-armed architectures with phenyl-Si(CH3)2-benzyl branches were detected as minor products. The comonomer sequence in the linear chains was established by MS(2) experiments on lithiated oligomers, based on the DMSS content of fragments generated by backbone C-C bond scissions and with the help of reference MS(2) spectra obtained from a polystyrene homopolymer and polystyrene end-capped with a p-DMSS block. The MS(2) data provided conclusive evidence that copolymerization of styrene/DMSS mixtures leads to chains with a rather random distribution of the silylated comonomer when m-DMSS is used, but to chains with tapered block structures, with the silylated units near the initiator, when p-DMSS is used. Hence, MS(2) fragmentation patterns permit not only differentiation of the sequences generated in the synthesis, but also the determination of specific comonomer locations along the polymer chain. PMID:25181590

Yol, Aleer M; Janoski, Jonathan; Quirk, Roderic P; Wesdemiotis, Chrys

2014-10-01

392

An evaluation of tandem mass spectrometry in drug metabolism studies.  

PubMed

The use of precursor ion and constant neutral loss scanning as a means of rapidly detecting drug metabolites is evaluated. Four clinically useful drugs, namely (i) cyclophosphamide, (ii) mifentidine, (iii) cimetropium bromide and (iv) haloperidol, were subjected to microsomal incubations to afford phase I metabolites. Aside from a minor clean-up procedure involving zinc sulfate precipitation of microsomal proteins and solid-phase extraction of metabolites using a Sep-pak C-18 cartridge, the mixtures were analysed directly by fast atom bombardment tandem mass spectrometry. It is demonstrated that such screening strategies are important in detecting novel metabolites. However, there are some problems associated with only using such methods, including (i) the possibility of not detecting metabolites that undergo unusual collision-induced dissociation fragmentation pathways, (ii) the non-detection of metabolites that have undergone metabolic change at unusual sites of reactivity, and (iii) production of artifacts derived from the parent drug by the primary ionization process. Examples are discussed that highlight both the strengths and weaknesses of such an approach. PMID:8102881

Naylor, S; Kajbaf, M; Lamb, J H; Jahanshahi, M; Gorrod, J W

1993-07-01

393

Solution structure and tandem DNA recognition of the C-terminal effector domain of PmrA from Klebsiella pneumoniae.  

PubMed

Klebsiella pneumoniae PmrA is a polymyxin-resistance-associated response regulator. The C-terminal effector/DNA-binding domain of PmrA (PmrAC) recognizes tandem imperfect repeat sequences on the promoters of genes to induce antimicrobial peptide resistance after phosphorylation and dimerization of its N-terminal receiver domain (PmrAN). However, structural information concerning how phosphorylation of the response regulator enhances DNA recognition remains elusive. To gain insights, we determined the nuclear magnetic resonance solution structure of PmrAC and characterized the interactions between PmrAC or BeF3(-)-activated full-length PmrA (PmrAF) and two DNA sequences from the pbgP promoter of K. pneumoniae. We showed that PmrAC binds to the PmrA box, which was verified to contain two half-sites, 5'-CTTAAT-3' and 5'-CCTAAG-3', in a head-to-tail fashion with much stronger affinity to the first than the second site without cooperativity. The structural basis for the PmrAC-DNA complex was investigated using HADDOCK docking and confirmed by paramagnetic relaxation enhancement. Unlike PmrAC, PmrAF recognizes the two sites simultaneously and specifically. In the PmrAF-DNA complex, PmrAN may maintain an activated homodimeric conformation analogous to that in the free form and the interactions between two PmrAC molecules aid in bending and binding of the DNA duplex for transcription activation. PMID:24371275

Lou, Yuan-Chao; Wang, Iren; Rajasekaran, M; Kao, Yi-Fen; Ho, Meng-Ru; Hsu, Shang-Te Danny; Chou, Shan-Ho; Wu, Shih-Hsiung; Chen, Chinpan

2014-04-01

394

Variation in Short Tandem Repeat sequences —a survey of twelve microsatellite loci for use as forensic identification markers  

Microsoft Academic Search

Alleles at 12 Short Tandem Repeat loci have been sequenced to investigate candidate loci for a multiplex Short Tandem Repeat system for forensic identification, and for single-locus amplification of Short Tandem Repeat loci. Variation from the consensus sequence was found at 6 loci, while one locus, D21S11, was found to be complex in sequence. The presence of non-consensus alleles does

A. Urquhart; C. P. Kimpton; T. J. Downes; P. Gill

1994-01-01

395

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

PubMed

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

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

2013-08-01

396

Multivalent Binding of Formin-binding Protein 21 (FBP21)-Tandem-WW Domains Fosters Protein Recognition in the Pre-spliceosome*  

PubMed Central

The high abundance of repetitive but nonidentical proline-rich sequences in spliceosomal proteins raises the question of how these known interaction motifs recruit their interacting protein domains. Whereas complex formation of these adaptors with individual motifs has been studied in great detail, little is known about the binding mode of domains arranged in tandem repeats and long proline-rich sequences including multiple motifs. Here we studied the interaction of the two adjacent WW domains of spliceosomal protein FBP21 with several ligands of different lengths and composition to elucidate the hallmarks of multivalent binding for this class of recognition domains. First, we show that many of the proteins that define the cellular proteome interacting with FBP21-WW1-WW2 contain multiple proline-rich motifs. Among these is the newly identified binding partner SF3B4. Fluorescence resonance energy transfer (FRET) analysis reveals the tandem-WW domains of FBP21 to interact with splicing factor 3B4 (SF3B4) in nuclear speckles where splicing takes place. Isothermal titration calorimetry and NMR shows that the tandem arrangement of WW domains and the multivalency of the proline-rich ligands both contribute to affinity enhancement. However, ligand exchange remains fast compared with the NMR time scale. Surprisingly, a N-terminal spin label attached to a bivalent ligand induces NMR line broadening of signals corresponding to both WW domains of the FBP21-WW1-WW2 protein. This suggests that distinct orientations of the ligand contribute to a delocalized and semispecific binding mode that should facilitate search processes within the spliceosome. PMID:21917930

Klippel, Stefan; Wieczorek, Marek; Schümann, Michael; Krause, Eberhard; Marg, Berenice; Seidel, Thorsten; Meyer, Tim; Knapp, Ernst-Walter; Freund, Christian

2011-01-01

397

Multivalent binding of formin-binding protein 21 (FBP21)-tandem-WW domains fosters protein recognition in the pre-spliceosome.  

PubMed

The high abundance of repetitive but nonidentical proline-rich sequences in spliceosomal proteins raises the question of how these known interaction motifs recruit their interacting protein domains. Whereas complex formation of these adaptors with individual motifs has been studied in great detail, little is known about the binding mode of domains arranged in tandem repeats and long proline-rich sequences including multiple motifs. Here we studied the interaction of the two adjacent WW domains of spliceosomal protein FBP21 with several ligands of different lengths and composition to elucidate the hallmarks of multivalent binding for this class of recognition domains. First, we show that many of the proteins that define the cellular proteome interacting with FBP21-WW1-WW2 contain multiple proline-rich motifs. Among these is the newly identified binding partner SF3B4. Fluorescence resonance energy transfer (FRET) analysis reveals the tandem-WW domains of FBP21 to interact with splicing factor 3B4 (SF3B4) in nuclear speckles where splicing takes place. Isothermal titration calorimetry and NMR shows that the tandem arrangement of WW domains and the multivalency of the proline-rich ligands both contribute to affinity enhancement. However, ligand exchange remains fast compared with the NMR time scale. Surprisingly, a N-terminal spin label attached to a bivalent ligand induces NMR line broadening of signals corresponding to both WW domains of the FBP21-WW1-WW2 protein. This suggests that distinct orientations of the ligand contribute to a delocalized and semispecific binding mode that should facilitate search processes within the spliceosome. PMID:21917930

Klippel, Stefan; Wieczorek, Marek; Schümann, Michael; Krause, Eberhard; Marg, Berenice; Seidel, Thorsten; Meyer, Tim; Knapp, Ernst-Walter; Freund, Christian

2011-11-01

398

Profiling of Parkin-Binding Partners Using Tandem Affinity Purification  

PubMed Central

Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting approximately 1–2% of the general population over age 60. It is characterized by a rather selective loss of dopaminergic neurons in the substantia nigra and the presence of ?-synuclein-enriched Lewy body inclusions. Mutations in the Parkin gene (PARK2) are the major cause of autosomal recessive early-onset parkinsonism. The Parkin protein is an E3 ubiquitin ligase with various cellular functions, including the induction of mitophagy upon mitochondrial depolarizaton, but the full repertoire of Parkin-binding proteins remains poorly defined. Here we employed tandem affinity purification interaction screens with subsequent mass spectrometry to profile binding partners of Parkin. Using this approach for two different cell types (HEK293T and SH-SY5Y neuronal cells), we identified a total of 203 candidate Parkin-binding proteins. For the candidate proteins and the proteins known to cause heritable forms of parkinsonism, protein-protein interaction data were derived from public databases, and the associated biological processes and pathways were analyzed and compared. Functional similarity between the candidates and the proteins involved in monogenic parkinsonism was investigated, and additional confirmatory evidence was obtained using published genetic interaction data from Drosophila melanogaster. Based on the results of the different analyses, a prioritization score was assigned to each candidate Parkin-binding protein. Two of the top ranking candidates were tested by co-immunoprecipitation, and interaction to Parkin was confirmed for one of them. New candidates for involvement in cell death processes, protein folding, the fission/fusion machinery, and the mitophagy pathway were identified, which provide a resource for further elucidating Parkin function. PMID:24244333

Blankenburg, Hagen; Doncheva, Nadezhda T.; Schwienbacher, Christine; Serafin, Alice; Alexa, Adrian; Weichenberger, Christian X.; Albrecht, Mario; Klein, Christine; Hicks, Andrew A.; Pramstaller, Peter P.

2013-01-01

399

Apparatus for continuously producing tandem amorphous photovoltaic cells  

SciTech Connect

A method and a multiple chamber apparatus for the continuous production of tandem, amorphous, photovoltaic solar cells on substrate material, whereby, at least six amorphous layers are continuously and sequentially deposited on the substrate material under steady conditions. The substrate material is driven from a supply core, through at least two triads of deposition chambers, to a take-up core. Each amorphous layer of each p-i-n-type cell is produced in one chamber of the triad of deposition chambers. In the first chamber of each triad of chambers, dopant gases are introduced to deposit a first conductive layer. In the second chamber of each triad of chambers, reaction gases are introduced to deposit an intrinsic layer atop the first layer. And in the third chamber of each triad of chambers, dopant gases are introduced to deposit a second conductive layer, opposite in conductivity from the first conductive layer, atop the intrinsic layer. The multiple chamber apparatus is constructed to substantially prevent the dopant gases in the first or third chamber from contaminating the intrinsic reaction gases in the second chamber of each triad of deposition chambers; and the dopant gases in the third chamber of one triad of deposition chambers and the dopant gases in the first chamber of an adjacent triad of deposition chambers from cross-contamination. In the preferred embodiment, the intrinsic material is an amorphous silicon alloy which is doped by boron to form a p-type alloy and doped by phosphorous to form an n-type alloy. The preferred embodiment further contemplates the use of a glow discharge deposition process wherein vacuum pressure conditions, temperature levels, reaction gas mixtures, reaction gas flow rates, cathode power generation levels, and substrate speed of travel are precisely controlled.

Ovshinsky, H.C.; Izu, M.

1985-01-08

400

Flow and noise predictions for the tandem cylinder aeroacoustic benchmarka)  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

401

Familial Lymphoproliferative Malignancies and Tandem Duplication of NF1 Gene  

PubMed Central

Background. Neurofibromatosis type 1 is a genetic disorder caused by loss-of-function mutations in a tumor suppressor gene (NF1) which codifies the protein neurofibromin. The frequent genetic alterations that modify neurofibromin function are deletions and insertions. Duplications are rare and phenotype in patients bearing duplication of NF1 gene is thought to be restricted to developmental abnormalities, with no reference to cancer susceptibility in these patients. We evaluated a patient who presented with few clinical signs of neurofibromatosis type 1 and a conspicuous personal and familiar history of different types of cancer, especially lymphoproliferative malignancies. The coding region of the NF-1 gene was analyzed by real-time polymerase chain reaction and direct sequencing. Multiplex ligation-dependent probe amplification was performed to detect the number of mutant copies. The NF1 gene analysis showed the following alterations: mosaic duplication of NF1, TRAF4, and MYO1D. Fluorescence in situ hybridization using probes (RP5-1002G3 and RP5-92689) flanking NF1 gene in 17q11.2 and CEP17 for 17q11.11.1 was performed. There were three signals (RP5-1002G3conRP5-92689) in the interphases analyzed and two signals (RP5-1002G3conRP5-92689) in 93% of cells. These findings show a tandem duplication of 17q11.2. Conclusion. The case suggests the possibility that NF1 gene duplication may be associated with a phenotype characterized by lymphoproliferative disorders. PMID:25580325

Fernandes, Gustavo; Souto, Mirela; Costa, Frederico; Oliveira, Edite; Garicochea, Bernardo

2014-01-01

402

Tandem Mass Spectrometry of Modified and Platinated Oligoribonucleotides  

NASA Astrophysics Data System (ADS)

Therapeutic approaches for treatment of various diseases aim at the interruption of transcription or translation. Modified oligonucleotides, such as 2'- O-methyl- and methylphosphonate-derivatives, exhibit high resistance against cellular nucleases, thus rendering application for, e.g., antigene or antisense purposes possible. Other approaches are based on administration of cross-linking agents, such as cis-diamminedichloroplatinum(II) (cisplatin, DDP), which is still the most widely used anticancer drug worldwide. Due to the formation of 1,2-intrastrand cross links at adjacent guanines, replication of the double-strand is disturbed, thus resulting in significant cytotoxicity. Evidence for the gas-phase dissociation mechanism of platinated RNA is given, based on nano-electrospray ionization high-resolution multistage tandem mass spectrometry (MS n ). Confirmation was found by investigating the fragmentation pattern of platinated and unplatinated 2'-methoxy oligoribonucleotide hexamers and their corresponding methylphosphonate derivatives. Platinated 2'-methoxy oligoribonucleotides exhibit a similar gas-phase dissociation behavior as the corresponding DNA and RNA sequences, with the 3'-C-O bond adjacent to the vicinal guanines being cleaved preferentially, leading to wx-ion formation. By examination of the corresponding platinated methylphosphonate derivatives of the 2'-methoxy oligoribonucleotides, the key role of the negatively charged phosphate oxygen atoms in direct proximity to the guanines was proven. The significant alteration of fragmentation due to platination is demonstrated by comparison of the fragment ion patterns of unplatinated and platinated 2'- O-methyl- and 2'- O-methyl methylphosphonate oligoribonucleotides, and the results obtained by H/D exchange experiments.

Nyakas, Adrien; Stucki, Silvan R.; Schürch, Stefan

2011-05-01

403

Generation of Tandem Direct Duplications by Reversed-Ends Transposition of Maize Ac Elements  

PubMed Central

Tandem direct duplications are a common feature of the genomes of eukaryotes ranging from yeast to human, where they comprise a significant fraction of copy number variations. The prevailing model for the formation of tandem direct duplications is non-allelic homologous recombination (NAHR). Here we report the isolation of a series of duplications and reciprocal deletions isolated de novo from a maize allele containing two Class II Ac/Ds transposons. The duplication/deletion structures suggest that they were generated by alternative transposition reactions involving the termini of two nearby transposable elements. The deletion/duplication breakpoint junctions contain 8 bp target site duplications characteristic of Ac/Ds transposition events, confirming their formation directly by an alternative transposition mechanism. Tandem direct duplications and reciprocal deletions were generated at a relatively high frequency (?0.5 to 1%) in the materials examined here in which transposons are positioned nearby each other in appropriate orientation; frequencies would likely be much lower in other genotypes. To test whether this mechanism may have contributed to maize genome evolution, we analyzed sequences flanking Ac/Ds and other hAT family transposons and identified three small tandem direct duplications with the structural features predicted by the alternative transposition mechanism. Together these results show that some class II transposons are capable of directly inducing tandem sequence duplications, and that this activity has contributed to the evolution of the maize genome. PMID:23966872

Peterson, Thomas

2013-01-01

404

Indium tin oxide-free tandem polymer solar cells on opaque substrates with top illumination.  

PubMed

Top-illuminated, indium tin oxide (ITO)-free, tandem polymer solar cells are fabricated on opaque substrates in an inverted device configuration. In the tandem cell, a wide band gap subcell, consisting of poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) blended with [70]PCBM is combined with a small band gap subcell consisting of a mixture of poly[{2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl}-alt-{[2,2'-(1,4-phenylene)bisthiophene]-5,5'-diyl}] (PDPPTPT) and [60]PCBM. Compared to the more common bottom-illuminated inverted tandem polymer solar cells on transparent ITO substrates, the front and back cells must be reversed when using opaque substrates and a transparent and conductive top contact must be employed to enable top illumination. A high conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer in combination with Ag lines surrounding the active area as current collection electrode is used for this purpose. The tandem polymer solar cell on an opaque glass/metal substrate yields a power conversion efficiency of 6.1% when the thicknesses of the photoactive layers are balanced for optimum performance. This is similar to the equivalent inverted tandem device fabricated on a transparent glass/ITO substrate. PMID:25051293

Gupta, Dhritiman; Wienk, Martijn M; Janssen, René A J

2014-08-27

405

Polymer-based parallel tandem solar cells with a transparent ferroelectric interconnecting layer  

NASA Astrophysics Data System (ADS)

We present a parallel polymer tandem solar cell that contains a transparent ferroelectric interconnecting layer based on polyvinylidene fluoride (PVDF) between two subcells. The interconnecting layer suppresses charge recombination, which leads to a large increase in short-circuit current and, thereby, effective parallel connection of the two subcells. The tandem cells maintained open-circuit voltages in the region between those of the subcells. An additional increase in the short-circuit current of the tandem cells was attained by introducing another ferroelectric layer to suppress charge recombination at the interface between the front subcell and a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) layer. As a result, a power conversion efficiency of 5.61% was obtained with the tandem structure PVDF/PCDTBT:PC71BM/PVDF/PTB7:PC71BM (PCDTBT is poly[N-9?-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)], PC71BM is [6,6]-phenyl-C71-butyric acid methyl ester, and PTB7 is thieno[3,4-b]-thiophene/benzodithiophene). The tandem cell was analyzed using a parallel two-diode circuit model. The results obtained from modeling showed excellent agreement with the experimental ones.

Bong Lee, Sang; Cheol Yoon, Sung; Seok Kim, Pan; Park, Sangman; Lim, Jongsun; Sup Yoon, Choon

2014-02-01

406

Ligand binding to WW tandem domains of YAP2 transcriptional regulator is under negative cooperativity.  

PubMed

YES-associated protein 2 (YAP2) transcriptional regulator drives a multitude of cellular processes, including the newly discovered Hippo tumor suppressor pathway, by virtue of the ability of its WW domains to bind and recruit PPXY-containing ligands to specific subcellular compartments. Herein, we employ an array of biophysical tools to investigate allosteric communication between the WW tandem domains of YAP2. Our data show that the WW tandem domains of YAP2 negatively cooperate when binding to their cognate ligands. Moreover, the molecular origin of such negative cooperativity lies in an unfavorable entropic contribution to the overall free energy relative to ligand binding to isolated WW domains. Consistent with this notion, the WW tandem domains adopt a fixed spatial orientation such that the WW1 domain curves outwards and stacks onto the binding groove of the WW2 domain, thereby sterically hindering ligand binding to both itself and its tandem partner. Although ligand binding to both WW domains disrupts such interdomain stacking interaction, they reorient themselves and adopt an alternative fixed spatial orientation in the liganded state by virtue of their ability to engage laterally so as to allow their binding grooves to point outwards and away from each other. In short, while the ability of WW tandem domains to aid ligand binding is well documented, our demonstration that they may also be subject to negative binding cooperativity represents a paradigm shift in our understanding of the molecular action of this ubiquitous family of protein modules. PMID:25283809

Schuchardt, Brett J; Mikles, David C; Hoang, Lawrence M; Bhat, Vikas; McDonald, Caleb B; Sudol, Marius; Farooq, Amjad

2014-12-01

407

Organic-inorganic halide perovskite/crystalline silicon four-terminal tandem solar cells.  

PubMed

Tandem solar cells constructed from a crystalline silicon (c-Si) bottom cell and a low-cost top cell offer a promising way to ensure long-term price reductions of photovoltaic modules. We present a four-terminal tandem solar cell consisting of a methyl ammonium lead triiodide (CH3NH3PbI3) top cell and a c-Si heterojunction bottom cell. The CH3NH3PbI3 top cell exhibits broad-band transparency owing to its design free of metallic components and yields a transmittance of >55% in the near-infrared spectral region. This allows the generation of a short-circuit current density of 13.7 mA cm(-2) in the bottom cell. The four-terminal tandem solar cell yields an efficiency of 13.4% (top cell: 6.2%, bottom cell: 7.2%), which is a gain of 1.8%abs with respect to the reference single-junction CH3NH3PbI3 solar cell with metal back contact. We employ the four-terminal tandem solar cell for a detailed investigation of the optical losses and to derive guidelines for further efficiency improvements. Based on a power loss analysis, we estimate that tandem efficiencies of ?28% are attainable using an optically optimized system based on current technology, whereas a fully optimized, ultimate device with matched current could yield up to 31.6%. PMID:25437303

Löper, Philipp; Moon, Soo-Jin; de Nicolas, Sílvia Martín; Niesen, Bjoern; Ledinsky, Martin; Nicolay, Sylvain; Bailat, Julien; Yum, Jun-Ho; De Wolf, Stefaan; Ballif, Christophe

2015-01-21

408

Detailed balance analysis of area de-coupled double tandem photovoltaic modules  

NASA Astrophysics Data System (ADS)

This paper describes how layers of area de-coupled top and bottom cells in photovoltaic tandem modules can increase the efficiency of two-terminal tandem devices. The point of the area de-coupling is to allow the number of top cells to differ from the number of bottom cells. Within each of the layers, the cells can be horizontally series-connected and the layers can then be current- or voltage-matched with each other in a tandem module. Using detailed balance modeling, it is shown that two-terminal tandem modules of this type can achieve the same theoretical efficiency as stacks of independently operated cells, often referred to as four-terminal cells. Optimal ratios of the number of bottom cells to the number of top cells are calculated. Finally, it is shown that modules with a bottom layer consisting of 60 cells with a band gap of 1.11 eV, resembling standard silicon modules, offer sufficient resolution to optimize the number of top cells and achieve high efficiency over a large range of top cell band gaps. This result extends the list of materials that can be used as top cells in two-terminal tandem modules with silicon bottom cells.

Strandberg, Rune

2015-01-01

409

Tandem DEDs and CARDs suggest novel mechanisms of signaling complex assembly.  

PubMed

Apoptosis is an important process to maintain cellular homeostasis. Deregulated apoptosis has linked to a number of diseases, such as inflammatory diseases, neurodegenerative disorder, and cancers. A major signaling complex in the death receptor signaling pathway leading to apoptosis is death-induced signaling complex (DISC), which is regulated mainly by death effector domain (DED)-containing proteins. There are seven DED-containing proteins in human, including FADD, c-FLIP, caspase-8, caspase-10, DEDD, DEDD2, and PEA-15. The main players in DISC formation employ tandem DEDs for regulating signaling complex formation. The regulatory mechanism of signaling complex formation is important and yet remains unclear. Interestingly, three caspase recruitment domain (CARD)-containing members, which belong to the same DD superfamily as DED-containing proteins, also contains similar tandem CARDs. Recent structural studies have shown that tandem CARDs are essential for the formation of a helical signaling complex. This review summarizes recent structural studies on DED-containing proteins and especially discusses the studies on tandem DEDs and tandem CARDs, which suggest new mechanisms of signaling complex assembly. PMID:25398537

Lo, Yu-Chih; Lin, Su-Chang; Yang, Chao-Yu; Tung, Jung-Yu

2015-02-01

410

Unsupervised land-cover classification using multitemporal ERS-1/2 tandem INSAR data  

NASA Astrophysics Data System (ADS)

In this study the potential of C-band interferometric SAR data in land-cover classification was investigated at a 2500km2 study area around the Helsinki metropolitan area in southern Finland. The area consists of a variety of land-use classes from dense urban areas to lakes, agricultural fields and boreal forests. The INSAR data consists of a time-series of 14 ERS-1/2 Tandem Image pairs with a 24 hour temporal baseline acquired during the ERS Tandem mission in 1995-1996. The data was interferometrically processed into 28 5-look intensity images, 14 Tandem coherence images and two coherence images with a longer temporal baseline (35 and 245 days). All image data was co-registered and orthorectified into map coordinates using an INSAR DEM. The dimension of the input dataset was reduced using Temporal Averaging and Principal Components Transformation (PCT) prior to classification. ISODATA unsupervised classification was performed on dataset consisting of the intensity and Tandem coherence temporal average images, the first intensity PC, two first Tandem coherence PCs and the average of the longtime coherence images. Classification accuracy was assessed by comparing the classification results with aerial orthophotos and digital base maps. Due to gaps in ground truth information overall accuracy and user's accuracy were not assessed. The overall producer's accuracy for six classes (agricultural fields, forest, vegetation, mixed urban, dense urban, water) was 80.9%.

Engdahl, Marcus E.; Hyyppa, Juha M.

2002-01-01

411

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...

412

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

PubMed

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

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

2012-06-19

413

Tandem structured quantum dot/rod sensitized solar cell based on solvothermal synthesized CdSe quantum dots and rods  

NASA Astrophysics Data System (ADS)

The quantum dots (QD) and quantum rods (QR) of different sizes, shapes, and crystalline phases are synthesized by modified solvothermal method spontaneously employed stirring system and controlled internal applied pressure. The tandem structure of QDs and QRs as well as tetrapods is formed on hierarchical porous titania photoanode by means of electrophoretic deposition. A tremendous enhancement in efficiency of the cell is obtained in samples synthesized at 220 °C for 24 h due to the formation of tandem structure, utilization of Cu2S/CNT composite cathode, co-sensitization of CdS and CdSe, and beneficial role of QRs in electron lifetime. Smaller size QDs with higher band gaps penetrate deeper through the macro-channels of the hierarchical porous structure, while the QRs and tetrapods with lower band gaps are placed on upper layers. Although the charge injection is improved in smaller QDs, the electron lifetime in QRs is longer mainly due to the higher absorption cross section, proper charge separation, introduction of quasi-one dimensional route for charge transport through QRs, and higher surface area available for regeneration with electrolyte. The cell shows the efficiency of 1.05% with JSC of 4.48 mA cm-2, VOC of 0.45 V, and fill factor of 0.52.

Golobostanfard, Mohammad Reza; Abdizadeh, Hossein

2014-06-01

414

Highly efficient purification of protein complexes from mammalian cells using a novel streptavidin-binding peptide and hexahistidine tandem tag system: Application to Bruton's tyrosine kinase  

PubMed Central

Tandem affinity purification (TAP) is a generic approach for the purification of protein complexes. The key advantage of TAP is the engineering of dual affinity tags that, when attached to the protein of interest, allow purification of the target protein along with its binding partners through two consecutive purification steps. The tandem tag used in the original method consists of two IgG-binding units of protein A from Staphylococcus aureus (ProtA) and the calmodulin-binding peptide (CBP), and it allows for recovery of 20–30% of the bait protein in yeast. When applied to higher eukaryotes, however, this classical TAP tag suffers from low yields. To improve protein recovery in systems other than yeast, we describe herein the development of a three-tag system comprised of CBP, streptavidin-binding peptide (SBP) and hexa-histidine. We illustrate the application of this approach for the purification of human Bruton's tyrosine kinase (Btk), which results in highly efficient binding and elution of bait protein in both purification steps (>50% recovery). Combined with mass spectrometry for protein identification, this TAP strategy facilitated the first nonbiased analysis of Btk interacting proteins. The high efficiency of the SBP-His6 purification allows for efficient recovery of protein complexes formed with a target protein of interest from a small amount of starting material, enhancing the ability to detect low abundance and transient interactions in eukaryotic cell systems. PMID:21080425

Li, Yifeng; Franklin, Sarah; Zhang, Michael J; Vondriska, Thomas M

2011-01-01

415

Microfluidic chip based nano liquid chromatography coupled to tandem mass spectrometry for the determination of abused drugs and metabolites in human hair.  

PubMed

A microfluidic chip based nano-HPLC coupled to tandem mass spectrometry (nano-HPLC-Chip-MS/MS) has been developed for simultaneous measurement of abused drugs and metabolites: cocaine, benzoylecgonine, cocaethylene, norcocaine, morphine, codeine, 6-acetylmorphine, phencyclidine, amphetamine, methamphetamine, MDMA, MDA, MDEA, and methadone in the hair of drug abusers. The microfluidic chip was fabricated by laminating polyimide films and it integrated an enrichment column, an analytical column and a nanospray tip. Drugs were extracted from hairs by sonication, and the chromatographic separation was achieved in 15 min. The drug identification and quantification criteria were fulfilled by the triple quardropule tandem mass spectrometry. The linear regression analysis was calibrated by deuterated internal standards with all of the R(2) at least over 0.993. The limit of detection (LOD) and the limit of quantification (LOQ) were from 0.1 to 0.75 and 0.2 to 1.25 pg/mg, respectively. The validation parameters including selectivity, accuracy, precision, stability, and matrix effect were also evaluated here. In conclusion, the developed sample preparation method coupled with the nano-HPLC-Chip-MS/MS method was able to reveal the presence of drugs in hairs from the drug abusers, with the enhanced sensitivity, compared with the conventional HPLC-MS/MS. PMID:22281681

Zhu, Kevin Y; Leung, K Wing; Ting, Annie K L; Wong, Zack C F; Ng, Winki Y Y; Choi, Roy C Y; Dong, Tina T X; Wang, Tiejie; Lau, David T W; Tsim, Karl W K

2012-03-01

416

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

SciTech Connect

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.

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

417

Influence of H2O/DEZ ratio on LPCVD ZnO:B films for application in a-Si:H/?c-Si:H tandem solar cells  

NASA Astrophysics Data System (ADS)

In this study, boron doped zinc oxide (ZnO:B) films were prepared at different water to diethyl zinc (H2O/DEZ) flow ratios from 0.6 to 1.4 by a low pressure chemical vapor deposition (LPCVD) technique. It is found that the morphology of ZnO:B films varies from small leaf-like to pyramidal surface structures with the increasing H2O/DEZ flow ratio. The rough ZnO:B films deposited at a relatively H2O/DEZ flow ratio such as 1.2 or 1.4 show a high haze value of up to 28 % at 600 nm and preferential crystallographic orientation. All ZnO:B films were applied in hydrogenated amorphous silicon/microcrystalline silicon tandem solar cells (a-Si:H/?c-Si:H) as front electrodes. The efficiency of the solar cells increases with the increasing H2O/DEZ flow ratio, which is attributed to a high spectral response mainly in the long-wavelength range and the consequent enhancement of short-circuit current. A high-efficiency a-Si:H/?c-Si:H tandem solar cell of 10 % was achieved. The H2O/DEZ ratio is an important process parameter to tune the material properties of LPCVD ZnO:B films and the performances of corresponding silicon thin film solar cells.

Wan, M.; Zhu, H.; Wang, Y.; Yin, J.; Gao, J.; Wang, Z.; Guan, F.; Mai, Y.; Huang, Y.; Yu, W.; Huang, S.

2014-04-01

418

Identification of Flavonoid Glycosides in Rosa chinensis Flowers by Liquid Chromatography-tandem Mass Spectrometry in Combination with 13C Nuclear Magnetic Resonance  

PubMed Central

Flowers of Rosa chinensis are widely used in traditional Chinese medicine as well as in food industry. Flavonoid glycosides are believed to be the major components in R. chinensis that are responsible for its antioxidant activities. In this work, a liquid chromatography-tandem mass spectrometry (HPLC- MS/MS) method was developed for analysis of flavonoid glycosides presented in ethyl acetate extract of dried R. chinensis flowers. Twelve flavonoid glycosides were separated and detected. By comparing the retention times, UV spectra, and tandem MS fragments with those of respective authentic compounds, eight flavonoid glycosides were unequivocally identified. Although the other four were also identified as flavonoid glycosides, the glycosylation positions could not be determined due to lack of authentic compounds. Fortunately, the glycosylation effects were clearly observed in the 13C NMR spectrum of the extract. The detailed structural information was, therefore, obtained to identify the four flavonoid glycosides as quercetin-3-O-D-glucoside, quercetin-3-O-D-xyloside, kaempferol-3-O-D-xyloside and quercetin-3-O-D-(6?-coumaroyl)-galactoside. These flavonoid glycosides were detected and identified for the first time in this botanic material. This work reports on the first use of 13C NMR of a mixture to enhance a rapid HPLC-MS/MS analysis. The proposed analytical protocol was validated with a mixture of authentic flavonoid glycosides. PMID:22749452

Qing, Lin-Sen; Xue, Ying; Zhang, Jian-Guang; Zhang, Zhi-Feng; Liang, Jian; Jiang, Yan; Liu, Yi-Ming; Liao, Xun

2012-01-01

419

Throughput analysis of tandem-type go-back-N ARQ scheme for satellite communications  

NASA Astrophysics Data System (ADS)

The tandem-type go-back-N (GBN) scheme has been proposed for satellite communications to reduce the long roundtrip delay using the on-board processing of satellites. In this paper, we consider the exact analysis of the throughput performance of this scheme and its application to a broadcast communications system such as a point-to-multipoint file transfer system. First, the throughput expression for the point-to-point tandem-type GBN scheme is derived. Second, applying the results of this point-to-point tandem-type GBN scheme to a broadcast (point-to-multipoint) communications system, the relationship of the number of receiving stations to the link bit error rate and the roundtrip propagation delay is shown.

Hayashida, Yukuo

1993-10-01

420

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

NASA Technical Reports Server (NTRS)

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.

Fisher, Edward M., Jr.

1991-01-01

421

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

422

Fourier transform two-dimensional fluorescence excitation spectrometer by using tandem Fabry-Pérot interferometer  

NASA Astrophysics Data System (ADS)

A Fourier transform two-dimensional fluorescence excitation spectrometer (FT-2DFES) was developed based on the multiplex technique using a tandem Fabry-Pérot interferometer (tandem FPI). In addition to the advantage of the multiplex technique, the main advantage of the tandem FPI is applicable to the modulation of transition with a large absorption bandwidth (larger than 100 nm) and is thus applicable to the modulation of the excitation of molecules in the condensed phase. As a demonstration of the effectiveness of FT-2DFES, we succeeded in separately observing the fluorescence excitation peaks from a mixed methanol solution of laser dyes (coumarin 480, rhodamine 6G, DCM (4-dicyanomethylene-2-methyl-6-(p-(dimethylamino)styryl)-4H-pyran), and LDS750). Furthermore, the energy transfer from rhodamine 6G to LDS750 was observed.

Anzai, Hiroshi; Joshi, Neeraj Kumar; Fuyuki, Masanori; Wada, Akihide

2015-01-01

423

Tandem repeats and heteroplasmy in the mitochondrial DNA control region of the loggerhead shrike (Lanius ludovicianus).  

PubMed

We report the presence of a 128 bp tandem repeat in the mitochondrial control region of the loggerhead shrike (Aves: Lanius ludovicianus). All individuals examined had either two or three copies of the repeat or were heteroplasmic for two and three copies. This is the first direct demonstration of a tandem repeat associated with heteroplasmy in the control region of a bird. A novel model for repeat duplication, which involves an inverted repeat located adjacent to the tandemly repeated sequence, is presented. Individuals with three repeats are absent from the endangered population of San Clemente loggerhead shrike in southern California, suggesting that the island endemic has a small effective population size and that there is insignificant gene flow from the adjacent mainland. PMID:8742819

Mundy, N I; Winchell, C S; Woodruff, D S

1996-01-01

424

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

SciTech Connect

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.

McNamara, B.

1984-04-01

425

Improvements of the research infrastructure at the tandem laboratory in IFIN-HH  

NASA Astrophysics Data System (ADS)

An extensive process of modernizing the research infrastructure started 6 years ago at the tandem accelerator in IFIN-HH. Major improvements of the 9 MV FN tandem accelerator installed in IFIN-HH in '73 were done in the late years, making it a very reliable machine, suited for basic and applied research experiments. The developments opened the way for new experiments made for the first time in our laboratory. Two new Cockroft-Walton tandem accelerators were also installed in 2012. The 1 MV HVE Tandetron accelerator is dedicated to AMS measurements, especially for 14C dating, while the 3 MV HVE Tandetron accelerator has the reaction chambers and detection system prepared for ion beam analysis measurements, microprobe experiments and ion implantation.

Ghi??, D. G.; Mou, D. V.; Dogaru, M.; Gugiu, M. M.; Popescu, I. V.; Dobrescu, S.; C?linescu, C. I.; C?ta-Danil, Gh.; En?chescu, M.; M?rginean, N.; Pantelic?, A.; Pantelic?, D.; Petre, A.; Sava, T. B.; Savu, B.; Simion, C. A.; Stan-Sion, C.; St?tescu, M.; Ionescu, P.; Zamfir, N. V.

2013-04-01

426

Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U)  

SciTech Connect

The Tandem Mirror Experiment-Upgrade (TMX-U) incorporates two new features at Lawrence Livermore National Laboratory (LLNL) tandem mirror program, thermal barriers in the end plugs and injection of the neutral beams at several oblique angles. The thermal barriers isolate the electrons in the end plugs from those in the central cell, making it possible to heat them independently with microwaves. In addition, this innovation produces a large potential gradient in the end plugs with lower magnetic fields and lower neutral-beam energies than would be possible in a conventional tandem mirror device. The TMX-U is also designed to test neutral-beam-injection angles as an experimental parameter. We use angles other than 90/sup 0/ to produce a plasma with improved microstability.

Chargin, A.K.; Calderon, M.O.; Moore, T.L.

1983-07-01

427

Gold-catalyzed tandem reactions of methylenecyclopropanes and vinylidenecyclopropanes.  

PubMed

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

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

2014-03-18

428

Aeroacoustic Simulations of Tandem Cylinders with Subcritical Spacing  

NASA Technical Reports Server (NTRS)

Tandem cylinders are being studied because they model a variety of component level interactions of landing gear. The present effort is directed at the case of two identical cylinders with their centroids separated in the streamwise direction by 1.435 diameters. Experiments in the Basic Aerodynamic Research Tunnel and Quiet Flow Facility at NASA Langley Research Center have provided an extensive experimental database of the nearfield flow and radiated noise. The measurements were conducted at a Mach number of 0.1285 and Reynolds number of 1.66x10(exp 5) based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent flow separation and, hence, to simulate a major aspect of 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 experiments exhibited an asymmetry in the surface pressure that was persistent despite attempts to eliminate it through small changes in the configuration. To model the asymmetry, the simulations were run with the cylinder configuration at a nonzero but small angle of attack. The computed results and experiments are in general agreement that vortex shedding for the spacing studied herein is weak relative to that observed at supercritical spacings. Although the shedding was subdued in the simulations, it was still more prominent than in the experiments. Overall, the simulation comparisons with measured near-field data and the radiated acoustics are reasonable, especially if one is concerned with capturing the trends relative to larger cylinder spacings. However, the flow details of the 1.435 diameter spacing have not been captured in full even though very fine grid computations have been performed. Some of the discrepancy may be associated with the simulation s inexact representation of the experimental configuration, but numerical and flow modeling errors are also likely contributors to the observed differences.

Lockard, David P.; Choudhari, Meelan M.; Khorrami, Mehdi R.; Neuhart, Dan H.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

2008-01-01

429

Design and Growth of III-V on Si Microwire Array Tandem Solar Cells Christopher T. Chen1  

E-print Network

Design and Growth of III-V on Si Microwire Array Tandem Solar Cells Christopher T. Chen1 , Daniel B Abstract -- Tandem Ga1-xInxP/Si microwire array solar cells are a route towards a high efficiency, low cost "buffer" layer between the bottom cell and tunnel junction is assumed to harbor a high density of lattice

Atwater, Harry

430

Database Search Algorithm for Identification of Intact Cross-Links in Proteins and Peptides Using Tandem Mass Spectrometry  

E-print Network

, Campus Chemical Instrument Center Mass Spectrometry and Proteomics Facility, the Ohio State University. Keywords: chemical cross-link · tandem mass spectrometry · database search · proteomics Introduction Three Tandem Mass Spectrometry Hua Xu,*,,,§ Pang-Hung Hsu,*,,|,,O Liwen Zhang,# Ming-Daw Tsai,|, and Michael A

Tsai, Ming-Daw

431

Measurement of Component Cell Current-Voltage Characteristics in a Tandem-JunctionTwo-Terminal Solar Cell  

E-print Network

of multijunction solar cells. Keywords Measurement method, I-V characteristics, component cells, tandem junctionTwo-Terminal Solar Cell Chandan Das, Xianbi Xiang and Xunming Deng Department of Physics and Astronomy, University-V) characteristics in a tandem-junction two-terminal solar cell is described. The measurements are performed with (a

Deng, Xunming

432

Overview of the Applications of Tandem Mass Spectrometry (MS\\/MS) in Food Analysis of Nutritionally Harmful Compounds  

Microsoft Academic Search

Tandem mass spectrometry (MS\\/MS) has proved to be a useful and a time saving analytical tool, with many applications of direct detection of target molecules in food samples. When coupled with chromatographic techniques, it combines the separation capabilities of chromatography and the power of MS\\/MS as an identification and confirmation method. This article reviews the use of tandem mass spectrometry

Stamatia I. Kotretsou; Aglaia Koutsodimou

2006-01-01

433

Genetic Diversity of Typha latifolia (Typhaceae) and the Impact of Pollutants Examined with Tandem-Repetitive DNA Probes  

Microsoft Academic Search

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 were to determine whether: (1) the previously reported almost complete lack of polymorphism at allozyme loci in this species was indicative of a reduced

Brian Keane; Stephan Pelikan; Greg P. Toth; M. Kate Smith; Steven H. Rogstad

1999-01-01

434

Roles of RIG-I N-terminal tandem CARD and splice variant in TRIM25-mediated antiviral  

E-print Network

Roles of RIG-I N-terminal tandem CARD and splice variant in TRIM25-mediated antiviral signal-I) recognizes viral RNA in a 5 -triphosphate- dependent manner and initiates an antiviral signaling cascade mutation in the second CARD elimi- nates polyubiquitin attachment. The necessity of the intact tandem CARD

Myong, Sua

435

Tandem reactions, cascade sequences, and biomimetic strategies in total K. C. Nicolaou,ab Tamsyn Montagnona and Scott A. Snydera  

E-print Network

Tandem reactions, cascade sequences, and biomimetic strategies in total synthesis K. C. Nicolaou bonds, particularly carbon­carbon bonds. In this respect, cascade and tandem reactions have long been December 2002 First published as an Advance Article on the web 16th January 2003 Cascade reactions

Snyder, Scott A.

436

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...

437

The EMBO Journal Vol.16 No.3 pp.588598, 1997 Concerted evolution of the tandemly repeated genes  

E-print Network

The EMBO Journal Vol.16 No.3 pp.588­598, 1997 Concerted evolution of the tandemly repeated genes by Elder and Turner, 1995), the mechanisms of only two polymorphisms within the U2 repeat unit: a concerted proposed to account for concerted evolution could not be junction regions flanking the tandem array fall

Kidd, Kenneth

438

High-efficiency GaInP\\/GaAs tandem solar cells  

Microsoft Academic Search

GaInP\\/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AM0) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them

K. A. Bertness; D. J. Friedman; Sarah R. Kurtz; A. E. Kibbler; C. Kramer; J. M. Olson

1994-01-01

439

High-efficiency GaInP\\/GaAs tandem solar cells  

Microsoft Academic Search

GaInP\\/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AMO) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them

K. A. Bertness; D. J. Friedman; S. R. Kurtz; A. E. Kibbler; C. Kramer; J. M. Olson

1994-01-01

440

Microwave heating of electrons in an end plug of the Phaedrus tandem mirror  

Microsoft Academic Search

Experiments were undertaken to investigate the heating of electrons in the tandem mirror Phaedrus by application of a microwave RF pulse into a single end plug (density n\\/sub p\\/ approx. 3.5 x 10¹² cm⁻³, ion energy E\\/sub i\\/ approx. 700 eV, and electron temperature T\\/sub e\\/ approx. 18 eV) of the tandem-mirror plasma. A 1-ms, 25-kW, 15.5-GHz microwave pulse resonant

Sing

1986-01-01

441

Synthesis of naphthalene amino esters and arylnaphthalene lactone lignans through tandem reactions of 2-alkynylbenzonitriles.  

PubMed

Tandem reaction of 2-alkynylbenzonitriles with a Reformatsky reagent turned out to be a novel and efficient approach toward 1-aminonaphthalene-2-carboxylates. Interestingly, with 2-(3-hydroxyprop-1-ynyl)benzonitriles as the substrates, a more sophisticated cascade process occurred to give 9-aminonaphtho[2,3-c]furan-1(3H)-ones in good yields. By using this tandem reaction as a key step, a concise and versatile synthetic strategy for the total synthesis of arylnaphthalene lactone lignans has been developed. PMID:24733055

He, Yan; Zhang, Xinying; Fan, Xuesen

2014-05-30

442

Thin film tandem solar cells based on II-VI compounds  

SciTech Connect

The R and D efforts for the production of thin film tandem solar cells are presented. The tandem structures are based on II-VI- and related compounds and are arranged as electrically isolated (4-terminal) cascades. For the high-bandgap part the material combinations under investigation are p-ZnTe/n-Zn /SUB x/ Cd /SUB 1-x/ S, pn-ZnSe /SUB y/ Te /SUB 1-y/ , and p-CuGaSe/sub 2// n-Zn /SUB x/ Cd /SUB 1-x/ S. The preliminary results of the investigations on all systems are promising; open circuit voltages of 1.3 V have been achieved.

Bloss, W.H.; Kimmerle, J.; Pfisterer, F.; Schock, W.H.

1984-05-01

443

Materials Science Division HVEM-Tandem Facility at Argonne National Laboratory  

SciTech Connect

The ANL-Materials Science Division High Voltage Electron Microscope-Tandem Facility is a unique national research facility available to scientists from industry, universities, and other national laboratories, following a peer evaluation of their research proposals by the Facility Steering Committee. The principal equipment consists of a Kratos EM7 1.2-MV high voltage electron microscope, a 300-kV Texas Nuclear ion accelerator, and a National Electrostatics 2-MV Tandem accelerator. Ions from both accelerators are transmitted into the electron microscope through the ion-beam interface. Recent work at the facility is summarized.

Taylor, A.

1981-10-01

444

Very high frequency plasma deposited amorphous/nanocrystalline silicon tandem solar cells on flexible substrates  

NASA Astrophysics Data System (ADS)

The work in this thesis is to develop high quality intrinsic layers (especially nc-Si:H) for micromorph silicon tandem solar cells/modules on plastic substrates following the substrate transfer method or knows as the Helianthos procedure. Two objectives are covered in this thesis: (1) preliminary work on trial and optimization of single junction and tandem cells on glass substrate, (2) silicon film depositions on Al foil, and afterwards the characterization and development of these cells/modules on a plastic substrate. The first objective includes the development of suitable ZnO:Al TCO for nc Si:H single junction solar cells, fabrication of the aimed micromorph tandem solar cells on glass, and finally the optimization of the nc-Si:H i-layer for the depositions afterwards on Al foil. Chapter 3 addresses the improvement of texture etching of ZnO:Al by studying the HCl etching effect on ZnO:Al films sputter-deposited in a set substrate heater temperature series. With the texture-etched ZnO:Al front TCO, a single junction nc-Si:H solar cell was deposited with an initial efficiency of 8.33%. Chapter 4 starts with studying the light soaking and annealing effects on micromorph tandem solar cell. In the end, a highly stabilized bottom cell current limited tandem cell was made. The tandem shows an initial efficiency of 10.2%, and degraded only 6.9% after 1600 h of light soaking. In Chapter 5, the nc-Si:H i-layers were studied in 3 pressure and inter-electrode distance series. The correlations between plasma physics and the consequent i-layers’ properties are investigated. We show that the Raman crystalline ratio and porosity of the nc-Si:H layer have an interesting relation with the p•d product. By varying p and d, device quality nc-Si:H layer can be deposited at a high rate of 0.6 nm/s. These results in fact are a very important step for the second objective. The second objective is covered by the entire Chapter 6. All silicon layers are deposited on special aluminum foils. Completed devices (including single junction a Si:H, nc-Si:H and micromorph silicon tandem cells/modules) on plastic substrates are characterized and discussed. In the end, 2.5 cm2 area micromorph tandem cells on foil were fabricated with an initial efficiency of the best cell to be 8.12% (FF = 0.64). After 1000 h of light soaking, its efficiency and FF degraded about 15% and 14.2% respectively.

Liu, Y.

2010-02-01

445

Displacement of particles in microfluidics by laser-generated tandem bubbles  

NASA Astrophysics Data System (ADS)

The dynamic interaction between laser-generated tandem bubble and individual polystyrene particles of 2 and 10 ?m in diameter is studied in a microfluidic channel (25 ?m height) by high-speed imaging and particle image velocimetry. The asymmetric collapse of the tandem bubble produces a pair of microjets and associated long-lasting vortices that can propel a single particle to a maximum velocity of 1.4 m/s in 30 ?s after the bubble collapse with a resultant directional displacement up to 60 ?m in 150 ?s. This method may be useful for high-throughput cell sorting in microfluidic devices.

Lautz, Jaclyn; Sankin, Georgy; Yuan, Fang; Zhong, Pei

2010-11-01

446

Improved set of short-tandem-repeat polymorphisms for screening the human genome  

SciTech Connect

Short-tandem-repeat (microsatellite) DNA polymorphisms are widely used for screening the human and other genomes in initial linkage mapping. Since the average spacing between polymorphisms in genome screens is usually {ge}10 cM and since many thousands of human short-tandem-repeat polymorphisms (STRPs) are now available, optimal subsets of STRPs must be selected for screening. Two screening sets of STRPs for humans have been described in the literature, both of which are based primarily on dinucleotide-repeat polymorphisms. Here we describe our eighth and most recent human screening set, which is based almost entirely on trinucleotide-and tetranucleotide-repeat polymorphisms. 7 refs., 1 tab.

Yuan, Bo; Vaske, D.; Weber, J.L. [Marshfield Medical Research Foundation, WI (United States)] [and others

1997-02-01

447

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

SciTech Connect

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.

Wang, Kangpeng; Ju, Yongfeng; He, Jin; Zhang, Long, E-mail: jwang@siom.ac.cn, E-mail: lzhang@siom.ac.cn; Wang, Jun, E-mail: jwang@siom.ac.cn, E-mail: lzhang@siom.ac.cn [Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Chen, Yu [Key Laboratory for Advanced Materials, Department of Chemistry, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Blau, Werner J. [Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); School of Physics and the Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)

2014-01-13

448

Organocatalytic asymmetric arylative dearomatization of 2,3-disubstituted indoles enabled by tandem reactions.  

PubMed

The organocatalytic asymmetric arylative dearomatization of indoles was achieved through two tandem approaches involving 2,3-disubstituted indoles and quinone imine ketals. One approach utilized the enantioselective cascade 1,4 addition/alcohol elimination reaction, the other employed the one-pot tandem arylative dearomatization/transfer hydrogenation sequence. In both cases, enantiomerically pure indole derivatives that bear an all-carbon quaternary stereogenic center were generated in high yields and excellent stereoselectivities (all d.r.>95:5, up to 99%?ee). PMID:25303741

Zhang, Yu-Chen; Zhao, Jia-Jia; Jiang, Fei; Sun, Si-Bing; Shi, Feng

2014-12-01

449

Photoelectrochemical and photovoltaic characteristics of amorphous-silicon-based tandem cells as photocathodes for water splitting.  

PubMed

In this study amorphous silicon tandem solar cells are successfully utilized as photoelectrodes in a photoelectrochemical cell for water electrolysis. The tandem cells are modified with various amounts of platinum and are combined with a ruthenium oxide counter electrode. In a two-electrode arrangement this system is capable of splitting water without external bias with a short-circuit current of 4.50 mA?cm(-2). On the assumption that no faradaic losses occur, a solar-to-hydrogen efficiency of 5.54% is achieved. In order to identify the relevant loss processes, additional three-electrode measurements were performed for each involved half-cell. PMID:25335095

Ziegler, Jürgen; Kaiser, Bernhard; Jaegermann, Wolfram; Urbain, Félix; Becker, Jan-Philipp; Smirnov, Vladimir; Finger, Friedhelm

2014-12-15

450

Tandem-pumped 1120-nm actively Q-switched fiber laser  

NASA Astrophysics Data System (ADS)

We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm. Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser, which is suppressed by pumping with a fiber laser at 1018 nm. At least four times improvement in output peak power is demonstrated in a single laser setup with 1018-nm fiber laser pumping instead of 976-nm laser diode pumping. This is, to the best of our knowledge, the first demonstration of a tandem-pumped Q-switched fiber laser.

Wang, Jian-Hua; Hu, Jin-Meng; Zhang, Shi-Qiang; Chen, Lu-Lu; Fang, Yong; Feng, Yan; Li, Zhi

2015-02-01

451

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

SciTech Connect

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.

Jiang, Zhenyu; You, Guanjun; Wang, Li; Liu, Jie; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Hu, Wenjia [China Tianchen Engineering Corporation, Tianjin 300400 (China); Zhang, Yu [State Key Laboratory on Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2014-08-28

452

The rRNA enhancer regulates rRNA transcription in Saccharomyces cerevisiae.  

PubMed Central

In Saccharomyces cerevisiae, the rRNA genes are organized as a tandem array of head-to-tail repeats. An enhancer of rRNA transcription is present just at the end of each transcription unit, 2 kb away from the next one. This enhancer is unusual for S. cerevisiae in that it acts both upstream and downstream of, and even across, genes. The role of the enhancer in the nutritional regulation of rRNA transcription was studied by introducing a centromere plasmid carrying two rRNA minigenes in tandem, flanking a single enhancer, into cells. Analysis of the transcripts from the two minigenes showed that the enhancer was absolutely required for the stimulation of transcription of rRNA that occurs when cells are shifted from a poor carbon source to a good carbon source. While full enhancer function is provided by a 45-bp region at the 3' end of the 190-bp enhancer, some activity was also conferred by other elements, including both a T-rich stretch and a region containing the binding sites for the proteins Reb1p and Abf1p. We conclude that the enhancer is composed of redundant elements and that it is a major element in the regulation of rRNA transcription. Images PMID:8423793

Morrow, B E; Johnson, S P; Warner, J R

1993-01-01

453

Determination of methylphenidate and its metabolite ritalinic acid in urine by liquid chromatography/tandem mass spectrometry.  

PubMed

Methylphenidate (MPH) is a drug that is licensed for treatment of ADHD and also narcolepsy. Monitoring of the parent drug and its major metabolite ritalinic acid (RA) in urine is considered necessary to ensure compliance with treatment programmes. A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of MPH and its metabolite RA in human urine. After urine was diluted with water, methylphenidate, the major metabolite ritalinic acid, and d?-amphetamine as the internal standard were resolved on a PFP propyl column using gradient elution of 0.02% ammonium formate and acetonitrile. The total analysis time was 13.5 min. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves were linear over the concentration range 5-5000 ?g/L (r>0.997), bias was ? ±20%, intra- and inter-day coefficients of variation (imprecision) were <8% and the limit of detection was 5 ?g/L. The limit of quantitation was set at 100 ?g/L. Matrix effects were up to 140% but these were accounted for by the internal standard. The assay is being used successfully in clinical practice to enhance the safe and effective use of methylphenidate. PMID:22204874

Paterson, Sharon M; Moore, Grant A; Florkowski, Chris M; George, Peter M

2012-01-15

454

Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: selection of extraction solvent.  

PubMed

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

Mol, Hans G J; van Dam, Ruud C J; Steijger, Odile M

2003-10-10

455

Quantitation of five organophosphorus nerve agent metabolites in serum using hydrophilic interaction liquid chromatography and tandem mass spectrometry.  

PubMed

Although nerve agent use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. Exposure can be detected through the analysis of hydrolysis products in urine as well as blood. An analytical method to detect exposure to five nerve agents, including VX, VR (Russian VX), GB (sarin), GD (soman), and GF (cyclosarin), through the analysis of the hydrolysis products, which are the primary metabolites, in serum has been developed and characterized. This method uses solid-phase extraction coupled with high-performance liquid chromatography for separation and isotopic dilution tandem mass spectrometry for detection. An uncommon buffer of ammonium fluoride was used to enhance ionization and improve sensitivity when coupled with hydrophilic interaction liquid chromatography resulting in detection limits from 0.3 to 0.5 ng/mL. The assessment of two quality control samples demonstrated high accuracy (101-105%) and high precision (5-8%) for the detection of these five nerve agent hydrolysis products in serum. PMID:24633507

Hamelin, Elizabeth I; Schulze, Nicholas D; Shaner, Rebecca L; Coleman, Rebecca M; Lawrence, Richard J; Crow, Brian S; Jakubowski, E M; Johnson, Rudolph C

2014-08-01

456

Proteomic analysis of human O {sup 6}-methylguanine-DNA methyltransferase by affinity chromatography and tandem mass spectrometry  

SciTech Connect

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.

Niture, Suryakant K. [Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106 (United States); Doneanu, Catalin E. [Mass Spectrometry Center, Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195 (United States); Velu, Chinavenmeni S. [Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106 (United States); Bailey, Nathan I. [Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106 (United States); Srivenugopal, Kalkunte S. [Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106 (United States)]. E-mail: Kalkunte.srivenugopal@ttuhsc.edu

2005-12-02

457

Rapid and sensitive analysis of 3,4-methylenedioxypyrovalerone in equine plasma using liquid chromatography-tandem mass spectrometry.  

PubMed

3,4-Methylenedioxypyrovalerone (MDPV) is a psychoactive drug with potent stimulant properties and potential for abuse and drug dependency. MDPV was recently classified as a Class I drug by Racing Commissioners International, indicating that it is a banned substance in equine athletes because it lacks therapeutic value in horses. To enforce this ban, a sensitive and fast liquid chromatography-tandem mass spectrometry method was needed. It is for this reason that this method was developed for quantification and confirmation of MDPV in equi