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1

A cell type-specific enhancer in the human B7.1 gene regulated by NF- kappaB  

PubMed Central

The costimulatory molecule B7.1 provides a second signal critical for T cell activation. The distribution of this integral membrane protein is restricted to certain tissues where its level of expression is modulated by multiple exogenous stimuli. To identify the molecular basis for specificity and inducibility, the chromatin configuration of the human B7.1 gene was examined in intact nuclei from various cell types. The identification of a tissue-specific deoxyribonuclease I hypersensitive site approximately 3kb upstream of the transcription start site led to the characterization of a cell type-specific enhancer region. This 183-bp region was both cell type specific and responsive to two distinct stimuli, lipopolysaccharide and dibutyryl cAMP, known to regulate B7.1 expression. Deletional and site-directed mutagenesis revealed the presence of multiple functionally critical cis elements within this region, one of which was a nuclear factor (NF)-kappaB consensus sequence. In B7.1-positive B cells, this element bound several members of the NF-kappaB family, transcription factors already implicated in signal transduction pathways relevant to B7.1 expression. This is the first description, to our knowledge, of regulatory elements that control expression of a gene encoding a B7 costimulatory molecule. PMID:8642282

1996-01-01

2

Tandem shock waves to enhance genetic transformation of Aspergillus niger.  

PubMed

Filamentous fungi are used in several industries and in academia to produce antibiotics, metabolites, proteins and pharmaceutical compounds. The development of valuable strains usually requires the insertion of recombinant deoxyribonucleic acid; however, the protocols to transfer DNA to fungal cells are highly inefficient. Recently, underwater shock waves were successfully used to genetically transform filamentous fungi. The purpose of this research was to demonstrate that the efficiency of transformation can be improved significantly by enhancing acoustic cavitation using tandem (dual-pulse) shock waves. Results revealed that tandem pressure pulses, generated at a delay of 300 ?s, increased the transformation efficiency of Aspergillus niger up to 84% in comparison with conventional (single-pulse) shock waves. This methodology may also be useful to obtain new strains required in basic research and biotechnology. PMID:24680880

Loske, Achim M; Fernández, Francisco; Magaña-Ortíz, Denis; Coconi-Linares, Nancy; Ortíz-Vázquez, Elizabeth; Gómez-Lim, Miguel A

2014-08-01

3

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

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

Microcavity-enhanced light-trapping for highly efficient organic parallel tandem solar cells.  

PubMed

A high-performance parallel tandem solar cell employing ultra-thin Ag as the intermediate anode is demonstrated, which comprises a semitransparent front sub-cell and a microcavity assisted back sub-cell. In addition to the extended optical field as a result of the tandem architecture, the prominent microcavity resonance formed in the back sub-cell enables such a parallel tandem configuration to possess high light utilization efficiency (the peak EQE value is over 80%) and a high photovoltaic performance of 9.2%. This study establishes an effective architecture that can be generally applicable to all organic materials for improving their performance. PMID:25168104

Zuo, Lijian; Chueh, Chu-Chen; Xu, Yun-Xiang; Chen, Kung-Shih; Zang, Yue; Li, Chang-Zhi; Chen, Hongzheng; Jen, Alex K-Y

2014-10-22

6

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

7

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

PubMed

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. PMID:23893238

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

2013-01-01

8

Activation of the nuclear factor kappaB pathway by astrocyte elevated gene-1: implications for tumor progression and metastasis.  

PubMed

Astrocyte elevated gene-1 (AEG-1) was initially identified as an HIV-1- and tumor necrosis factor alpha (TNF-alpha)-inducible transcript in primary human fetal astrocytes by a rapid subtraction hybridization approach. Interestingly, AEG-1 expression is elevated in subsets of breast cancer, glioblastoma multiforme and melanoma cells and AEG-1 cooperates with Ha-ras to promote transformation of immortalized melanocytes. Activation of the transcription factor nuclear factor kappaB (NF-kappaB), a TNF-alpha downstream signaling component, is associated with several human illnesses, including cancer, and NF-kappaB controls the expression of multiple genes involved in tumor progression and metastasis. We now document that AEG-1 is a significant positive regulator of NF-kappaB. Enhanced expression of AEG-1 via a replication-incompetent adenovirus (Ad.AEG-1) in HeLa cells markedly increased binding of the transcriptional activator p50/p65 complex of NF-kappaB. The NF-kappaB activation induced by AEG-1 corresponded with degradation of IkappaBalpha and nuclear translocation of p65 that resulted in the induction of NF-kappaB downstream genes. Infection with an adenovirus expressing the mt32IkappaBalpha superrepressor (Ad.IkappaBalpha-mt32), which prevents p65 nuclear translocation, inhibited AEG-1-induced enhanced agar cloning efficiency and increased matrigel invasion of HeLa cells. We also document that TNF-alpha treatment resulted in nuclear translocation of both AEG-1 and p65 wherein these two proteins physically interacted, suggesting a potential mechanism by which AEG-1 could activate NF-kappaB. Our findings suggest that activation of NF-kappaB by AEG-1 could represent a key molecular mechanism by which AEG-1 promotes anchorage-independent growth and invasion, two central features of the neoplastic phenotype. PMID:16452207

Emdad, Luni; Sarkar, Devanand; Su, Zao-zhong; Randolph, Aaron; Boukerche, Habib; Valerie, Kristoffer; Fisher, Paul B

2006-02-01

9

Pulsed multiple reaction monitoring approach to enhancing sensitivity of a tandem quadrupole mass spectrometer.  

PubMed

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

2011-03-15

10

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

SciTech Connect

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

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

2011-02-23

11

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

PubMed

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

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

2013-11-01

12

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

2014-11-17

13

Effect of resveratrol on activation of nuclear factor kappa-B and inflammatory factors in rat model of acute pancreatitis  

PubMed Central

AIM: To observe the effect of resveratrol on nuclear factor Kappa-B (NF-?B) activation and the inflammatory response in sodium taurocholate-induced pancreatitis in rats. METHODS: Seventy-two male SD rats were randomly divided into three groups: sham operation group (control), severe acute pancreatitis (SAP) group, and severe acute pancreatitis group treated with resveratrol (RES). A SAP model was established by injecting 4% sodium taurocholate 1 mL/kg through puncturing the pancreatic duct. In Res group, Res was given at 30 mg/kg b.m. intraperitoneally after the SAP model was successfully established. Eight animals from each group were sacrificed at 3, 6 and 12 h after modeling. The expression of NF-?B activation of pancreas was detected by immunohistochemical staining, whereas the levels of TNF-? and IL-8 in pancreatic tissues were estimated by radioimmunoassay. The pathological changes of pancreas and lungs were examined microscopically. RESULTS: Much less hyperemia, edema, dust-colored necrotic focus and soaps were noticed in pancreas in RES group than in SAP group. In RES group, hemorrhage, exudates and infiltration of inflammatory cells in pancreas and interstitial edema, destruction of alveolar wall in lung were significantly less than in SAP group. In the SAP group, the activation of NF-?B in pancreatic tissues was enhanced significantly at any measure point compared with control group (64.23±10.72% vs 2.56±0.65%, 55.86±11.34% vs 2.32±0.42%, 36.23±2.30% vs 2.40±0.36%,P <0.01), TNF-?,IL-8 were also increased and reached their peak at 6 h and then declined. The activation of NF-?B and the levels of TNF-? and IL-8 in RES group were significantly lower than those in SAP group (P<0.01): activation (52.63±9.45% vs 64.23±10.72%, 40.52±8.40% vs 55.86±11.34%, 29.83±5.37% vs 36.23±2.30%), TNF-? (132.76±15.68 pg/mL vs 158.36±12.58 pg/mL, 220.32±23.57 pg/mL vs 247.67± 11.62 pg/mL, 175.68±18.43 pg/mL vs 197.35±12.57 pg/mL) and IL-8 (0.62±0.21 ?g/L vs 0.83±0.10 ?g/L, 1.10±0.124 ?g/L vs 1.32±0.18 ?g/L, 0.98±0.16 ?g/L vs 1.27±0.23 ?g/L). CONCLUSION: The activation of NF-?B is involved in the inflammatory response of rats with SAP. Resveratrol could effectively inhibit the expression of NF-?B activation, alleviate the severity of SAP through its anti-inflammatory effects and regulate the inflammatory mediators. PMID:15641139

Meng, Yong; Ma, Qing-Yong; Kou, Xiao-Ping; Xu, Jun

2005-01-01

14

Determination of Androgen Receptor Degradation Enhancer ASC-J9® in Mouse Sera and Organs with Liquid Chromatography Tandem Mass Spectrometry  

PubMed Central

A novel androgen receptor (AR) degradation enhancer ASC-J9® has displayed beneficial effects during the in vitro and in vivo studies for treatment of prostate cancer, liver cancer, bladder cancer and spinal and bulbar muscular atrophy (SBMA). It works mainly by inducing the degradation of AR with minimal side effects on the tested mice. Here we developed a fast, robust and more sensitive method for the quantification of ASC-J9® in 100 ?L of mouse serum by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The limit of quantification (LOQ) was found to be 5nM for ASCJ9®. This method was successfully applied to investigate the pharmacokinetics of ASC-J9® in mice serum samples and also the distribution of the drug in various mice organs after single dose injection with results showing that ASC-J9® could be quickly absorbed in vivo and had a relatively slow elimination half-life of 5.45 h. The ASC-J9® also exhibited a higher tendency to accumulate in organs such as liver, testes and prostate. PMID:24042123

Soh, Shu Fang; Huang, Chiung-Kuei; Lee, Soo Ok; Xu, Defeng; Yeh, Shuyuan; Li, Jun; Yong, Eu Leong; Gong, Yinhan; Chang, Chawnshang

2013-01-01

15

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

16

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

17

Association of sustained ERK activity with integrin ?3 induction during receptor activator of nuclear factor kappaB ligand (RANKL)-directed osteoclast differentiation  

Microsoft Academic Search

Osteoclast differentiation is a multi-step process that involves cell proliferation, commitment, and fusion. Some adhesion molecules, including integrin ?v?3, have been shown to have roles in osteoclast fusion. In the course of studying with pharmacologic agents known to inhibit protein tyrosine kinases of the Src family, we found that radicicol increased cell fusion during receptor activator of nuclear factor kappaB

Hong-Hee Kim; Woon Jae Chung; Soo Woong Lee; Pah-Jin Chung; Jae Won You; Ho Jeong Kwon; Sakae Tanaka; Zang Hee Lee

2003-01-01

18

Isolation and tandem mass fragmentations of an anti-inflammatory compound from Aralia elata.  

PubMed

One-step isolation of a saponin from Aralia elata was undertaken using high-speed countercurrent chromatography coupled with evaporative light scattering detection. A triterpenoid saponin, elatoside F, was purified with 96.8% purity using a two-phase-system comprising chloroform-methanol-water-isopropanol. The yield was 35.0 mg from 348.2 mg of the enriched saponin fraction. In vitro anti-inflammatory study demonstrated that elatoside F inhibited lipopolysaccharide-induced nitric oxide production, as well as nuclear factor kappaB activation, in a dose-dependent manner. Two types of mass ionization technique were compared on elatoside F to investigate characteristic fragmentation patterns. MALDI-TOF tandem mass spectrometric fragmentation patterns of sodiated ions provided structural information on glycosidic cleavages and on extensive cross-ring cleavages. Electrospray ionization multiple-stage tandem mass fragmentation of both sodiated and lithiated ions could provide information on glycosidic cleavages. All observed tandem mass fragmentation spectra provided valuable elatoside F structural information when unknown samples from crude extracts are under screening by mass spectrometry. PMID:19557359

Lee, Ju Hyeon; Ha, Young Wan; Jeong, Choon Sik; Kim, Yeong Shik; Park, Youmie

2009-06-01

19

Tandem hydrofoil system  

Microsoft Academic Search

A tandem hydrofoil system enables an improvement in the lift-drag ratio of a high-speed ship. The conditions for favorable application of this type of foil structure are determined. The data on hydrofoil boats using a tandem system are presented. The problem of the stability of the vertical plane motion of a hydrofoil with bow and stern foils is considered. The

Konstantin I. Matveev; Ivan Ivanovich Matveev

2001-01-01

20

Ajoene, a compound of garlic, induces apoptosis in human promyeloleukemic cells, accompanied by generation of reactive oxygen species and activation of nuclear factor kappaB.  

PubMed

The pharmacological role of garlic in prevention and treatment of cancer has received increasing attention, but thorough investigations into the molecular mechanisms of action of garlic compounds are rare. The present study demonstrates that ajoene, a major compound of garlic induces apoptosis in human leukemic cells, but not in peripheral mononuclear blood cells of healthy donors. The effect was dose and time dependent. Apoptosis was judged by three criteria, morphology of cells, quantification of subdiploid DNA content by flow cytometry, and detection of DNA fragmentation by gel electrophoresis. Ajoene increased the production of intracellular peroxide in a dose- and time-dependent fashion, which could be partially blocked by preincubation of the human leukemic cells with the antioxidant N-acetylcysteine. Interestingly, N-acetylcysteine-treated cells showed a 50% loss of ajoene-induced apoptosis. Moreover, ajoene was demonstrated to activate nuclear translocation of the transcription factor nuclear factor kappaB, an effect that was abrogated in N-acetylcysteine-loaded cells. These results suggested that ajoene might induce apoptosis in human leukemic cells via stimulation of peroxide production and activation of nuclear factor kappaB. This is a novel aspect in the biological profile of this garlic compound and an important step in elucidating the underlying molecular mechanisms of its antitumor action. PMID:9495804

Dirsch, V M; Gerbes, A L; Vollmar, A M

1998-03-01

21

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

22

5,7-dihydroxy-3,4,6-trimethoxyflavone inhibits the inflammatory effects induced by Bacteroides fragilis enterotoxin via dissociating the complex of heat shock protein 90 and I kappaB alpha and I kappaB kinase-gamma in intestinal epithelial cell culture.  

PubMed

Enterotoxin produced by enterotoxigenic Bacteroides fragilis (BFT) has been associated with mucosal inflammation and diarrhoeal diseases. In this study, the anti-inflammatory molecular mechanism of 5,7-dihydroxy-3,4,6-trimethoxyflavone (eupatilin) was characterized in an HT-29 intestinal epithelial cell line stimulated with BFT. Pre-treatment of HT-29 cells with eupatilin decreased the production significantly of both interleukin (IL)-8 and prostaglandin E(2) induced by BFT in a dose-dependent manner. BFT-activated nuclear factor-kappaB (NF-kappaB) signals in HT-29 cells and pretreatment with eupatilin suppressed NF-kappaB activation that resulted in the significant inhibition of IL-8 and cyclo-oxygenase-2 expression. BFT-induced phosphorylation of both I kappaB alpha and I kappaB kinase (IKK) signals was prevented in eupatilin-pretreated HT-29 cells. Transfection of siRNA for IKK-alpha and IKK-beta decreased the production of IL-8 and prostaglandin E(2); however, the transfection of IKK-beta siRNA showed a more significant reduction of BFT-induced I kappaB alpha phosphorylation compared with that of IKK-alpha siRNA. In addition, herbimycin A, a specific inhibitor of heat shock protein 90 (Hsp90), decreased the BFT-induced activation of IKK and NF-kappaB, suggesting that Hsp90 is associated with a pathway of IKK-NF-kappaB-IL-8/cyclo-oxygenase-2 gene signalling. Furthermore, eupatilin dissociated the complex between Hsp90 and IKK-gamma in BFT-stimulated HT-29 cells. These results suggest that eupatilin can suppress the NF-kappaB signalling pathway by targeting the Hsp90-IKK-gamma complex in intestinal epithelial cells and may attenuate BFT-induced inflammatory responses. PMID:19220840

Kim, J M; Lee, D H; Kim, J S; Lee, J Y; Park, H-G; Kim, Y-J; Oh, Y-K; Jung, H C; Kim, S I

2009-03-01

23

Simple and practical derivatization procedure for enhanced detection of carboxylic acids in liquid chromatography-electrospray ionization-tandem mass spectrometry.  

PubMed

A simple and practical derivatization procedure for increasing the detection responses of carboxylic acids in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) has been developed. 2-Hydrazinopyridine (HP) and 2-picolylamine (PA) rapidly reacted with biologically and clinically important carboxylic acids [chenodeoxycholic acid, glycochenodeoxycholic acid, prostaglandin E2, 2-(-carboxyethyl)-6-hydroxy-2,7,8-trimethylchroman (gamma-CEHC),alpha-lipoic acid, homovanillic acid (HVA) and 5-hydroxyindole-3-acetic acid] in the presence of 2,2'-dipyridyl disulfide and triphenylphosphine. The resulting HP- and PA-derivatives were highly responsive in ESI-MS operating in the positive-ion mode and gave characteristic product ions during MS/MS, which enabled the sensitive detection using selected reaction monitoring. Among the two reagents, PA was of more practical use; the detection responses of the PA-derivatives were increased by 9-158-fold over the intact carboxylic acids and the limits of detection were in the low femtomole range (1.5-5.6 fmol on column). The PA-derivatization was successfully applied to a biological sample analysis; the derivatization followed by LC-ESI-MS/MS enabled the detection of trace amounts of bile acids, gamma-CEHC and HVA in human saliva with a simple pretreatment, small sample volume and short analysis time. PMID:20376914

Higashi, Tatsuya; Ichikawa, Takuya; Inagaki, Shinsuke; Min, Jun Zhe; Fukushima, Takeshi; Toyo'oka, Toshimasa

2010-09-01

24

Insulin-like growth factor-I protects colon cancer cells from death factor-induced apoptosis by potentiating tumor necrosis factor alpha-induced mitogen-activated protein kinase and nuclear factor kappaB signaling pathways.  

PubMed

Resistance of cancer cells against apoptosis induced by death factors contributes to the limited efficiency of immune- and drug-induced destruction of tumors. We report here that insulin and insulin-like growth factor-I (IGF-I) fully protect HT29-D4 colon carcinoma cells from IFN-gamma/tumor necrosis factor-alpha (TNF) induced apoptosis. Survival signaling initiated by IGF-I was not dependent on the canonical survival pathway involving phosphatidylinositol 3'-kinase. In addition, neither pp70(S6K) nor protein kinase C conveyed IGF-I antiapoptotic function. Inhibition of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) with the MAPK/ERK kinase inhibitor PD098059 and MAPK/p38 with the specific inhibitor SB203580 partially reversed, in a nonadditive manner, the IGF-I survival effect. Inhibition of nuclear factor kappaB (NF-kappaB) activity by preventing degradation of the inhibitor of NF-kappaB (IkappaB-alpha) with BAY 11-7082 also blocked in part the IGF-I antiapoptotic effect. However, the complete reversal of the IGF-I effect was obtained only when NF-kappaB and either MAPK/ERK or MAPK/p38 were inhibited together. Because these pathways are also those used by TNF to signal inflammation and survival, these data point to a cross talk between IGF-I- and TNF-induced signaling. We further report that TNF-induced IL-8 production was indeed strongly enhanced upon IGF-I addition, and this effect was totally abrogated by both MAPK and NF-kappaB inhibitors. The IGF-I antiapoptotic function was stimulus-dependent because Fas- and IFN/Fas-induced apoptosis was not efficiently inhibited by IGF-I. This was correlated with the weak ability of Fas ligation to enhance IL-8 production in the presence or absence of IGF-I. These findings indicate that the antiapoptotic function of IGF-I in HT29-D4 cells is based on the enhancement of the survival pathways initiated by TNF, but not Fas, and mediated by MAPK/p38, MAPK/ERK, and NF-kappaB, which act in concert to suppress the proapoptotic signals. In agreement with this model, we show that it was possible to render HT29-D4 cells resistant to Fas-induced apoptosis provided that IGF-I and TNF receptors were activated simultaneously. PMID:10766192

Remacle-Bonnet, M M; Garrouste, F L; Heller, S; André, F; Marvaldi, J L; Pommier, G J

2000-04-01

25

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

26

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

27

Monolithic tandem solar cell  

SciTech Connect

It is an object of the invention to provide a monolithic tandem photovoltaic solar cell which is highly radiation resistant and efficient; in which the energy bandgap of the lower subcell can be tailored for specific applications; solar cell comprising layers of InP and GaInAsP (or GaInAs), where said photovoltaic cell is useful, for example, in space power applications; having an improved power-to-mass ratio; in which subcells are lattice-matches; and are both two terminal and three terminal monolithic tandem photovoltaic solar cells. To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the monolithic tandem photovoltaic solar cell may comprise; (a) an InP substrate having an upper surface; (b) a first photoactive subcell on the upper surface of the InP substrate; wherein the first subcell comprises GaInAs (which could include GaInAsP) and includes a homojunction; and (c) a second photoactive subcell on the first subcell; wherein the second subcell comprises InP and includes a homojunction. The cell is described in detail. 5 figs., 2 tabs.

Wanlass, M.W.

1989-11-03

28

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

29

Homosexual tandem running as selfish herd in Reticulitermes speratus: novel antipredatory behavior in termites.  

PubMed

We investigated the predator avoidance mechanism of post-swarming alates of the lower subterranean termite, Reticulitermes speratus Kolbe. In some lower termites, homosexual tandem running is observed in addition to ordinary heterosexual tandem running. An experiment designed to compare the risk of predation by a termite-hunting ant, Brachyponera chinensis Emery, showed that homosexual tandem running reduced the predation risk until termites encounter the opposite sex. Since an individual ant cannot capture two dealates at once, one of the two dealates forming a tandem can escape while the ant captures its partner. Therefore, the "post-encounter risk" of individuals running in tandem was lower than that of single individuals. The "encounter risk" with predatory ants was also examined using a mathematical model considering the increased detectability of the predator due to enhanced size of the prey unit. It was suggested that tandem running reduces the predation risk of both participants, even when the enhanced encounter risk was taken into account. In males, competition for the back position was often observed, and consequently, the male at the back was always larger than the male in front. When a male-male tandem encountered a female, the back male won the female more often than the front male. This result suggested that male-male tandem running should result in selection pressure in favor of vigorous males. In conclusion, tandem running decreases the individual predation risk through the dilution effect, and it also plays a role as a mechanism of indirect sexual selection. PMID:11786032

Matsuura, Kenji; Kuno, Eizi; Nishida, Takayoshi

2002-01-01

30

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

31

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 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.

Wanlass, Mark W. (Golden, CO)

1994-01-01

32

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, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

Wanlass, Mark W. (Golden, CO)

1991-01-01

33

Monolithic tandem solar cell  

SciTech Connect

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

Wanlass, M.W.

1991-05-28

34

Requirement of RhoA activity for increased nuclear factor kappaB activity and PC-3 human prostate cancer cell invasion.  

PubMed

To determine the molecular mechanisms of aggressive prostate cancer behavior, we studied RhoGTPases in high and low invasive variants of PC-3 prostate cancer cells. Prior studies with these cells revealed that elevated nuclear factor kappaB (NF-kappaB) expression and activity were necessary for the highly invasive phenotype. In the current study, increased RhoA expression was found in the PC-3 highly invasive cells as compared with the PC-3 low invasive cells through cDNA array and Western blot analyses. Similarly, RhoA activity, as measured by the Rhotekin binding assay, was elevated in the PC-3 highly invasive cells. Transfection of these highly invasive cells with dominant negative RhoA N19 or treatment with 1.0 micro g/ml RhoA inhibitor C3 exoenzyme demonstrated that RhoA activity was necessary for both NF-kappaB activity and cellular invasion of a Matrigel reconstituted basement membrane. Furthermore, stable transfection of the PC-3 highly invasive cells with constitutively active RhoA Q63L resulted in activation of NF-kappaB activity and Matrigel invasion, effects reversed by treatment of the cells with C3 exoenzyme. RhoA was also shown to act through the motility component of the invasion process. RhoA activity was therefore both necessary and sufficient for the elevated NF-kappaB, invasion, and motility activities of the PC-3 highly invasive cells. These findings suggest molecular targets to control cancer cell invasion and aid in the development of definitive tools for predicting the invasive and metastatic potential of cancer cells. PMID:12649199

Hodge, Jennelle C; Bub, Jeffrey; Kaul, Sushma; Kajdacsy-Balla, André; Lindholm, Paul F

2003-03-15

35

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

SciTech Connect

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

Theoleyre, S. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Kwan Tat, S. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Vusio, P. [IFR26, Institut de Biologie, Nantes Hospital (France); Blanchard, F. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Gallagher, J. [Department of Medical Oncology, PICR, Christie Hospital NHS Trust, Wilmslow Rd, Manchester M20 4BX (United Kingdom); Ricard-Blum, S. [CNRS, UMR 5086, UCBL, Institut de Biologie et Chimie des Proteines, 7 passage du Vercors 69367 Lyon Cedex 07 (France); Fortun, Y. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Universite d'Angers, IUT (France); Padrines, M. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Redini, F. [INSERM, ERI 7, Nantes, F-44035 (France); Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France); Heymann, D. [INSERM, ERI 7, Nantes, F-44035 (France) and Universite de Nantes, Laboratoire de Physiopathologie de la Resorption Osseuse et Therapie des Tumeurs Osseuses Primitives, EA3822, Nantes F-44035 (France)]. E-mail: dominique.heymann@univ-nantes.fr

2006-08-25

36

Nuclear factor kappaB is downregulated and correlates with p53 in the Min mouse mucosa during an accelerated tumor growth.  

PubMed

The nuclear factor kappaB signaling pathway has gained attention for its role in the carcinogenic process. We have measured the protein levels of the p65 subunit during a growth of adenomas in the Min mouse model for colon cancer. To study how an accelerated growth of adenomas affect cell signalling, adenoma growth was increased by an inulin diet (10%) that we have shown previously to be a promotor of adenoma formation. In our study, the association between NF-kappaB, p53, beta-catenin, Fas and COX-2 were evaluated by measuring their protein levels in 9- and 15-week old Min mouse adenomas and surrounding mucosa. The amount of p65 rouse between 9- and 15-weeks in the mucosa of the control-fed mice (p = 0.032). The inulin-fed mice had less p65 in the nucleus of the mucosa at 15 weeks of age compared to the control (p = 0.064), although the adenomas were significantly larger (1.46 mm +/- 0.12 for inulin, 0.97 mm +/- 0.12 for control, p < 0.001). Nuclear p65 correlated positively with nuclear p53 in the mucosa (p < 0.001) and adenoma (p < 0.001) tissues. Also, p65 correlated positively with nuclear beta-catenin in the mucosa (p = 0.012) and the adenoma (p = 0.001). Fas expression increased in the inulin group between 9-15 weeks (p = 0.034) and correlated negatively with p65 (p = 0.03). The amount of COX-2 in the adenoma tissue increased between 9-15 weeks and did not correlate with p65. The results suggest that p65 is involved in a p53-dependent apoptotic response in the Min mouse. PMID:16049962

Rajakangas, Johanna; Pajari, Anne-Maria; Misikangas, Marjo; Mutanen, Marja

2006-01-15

37

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

38

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

SciTech Connect

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

Zhang Yankai [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Yan Rong [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); He Yi [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Liu Wentao [Nanjing Medical University, Nanjing 210029 (China); Cao Rongyue [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Yan Ming [National Drug Screening Laboratory, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Li Taiming [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Liu Jingjing [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China); Wu Jie [Minigene Pharmacy Laboratory, Biopharmaceutical College, China Pharmaceutical University, Tongjia Xiang 24, Nanjing 210009 (China)]. E-mail: wu_jie97@yahoo.com.cn

2006-07-14

39

Microstability of the TMX tandem mirror experiments  

SciTech Connect

In the tandem mirror device, an efficient source of warm ions, the central cell, is available for stabilization of ion loss-cone instabilities. These instabilities previously limited ion confinement in single-cell mirror experiments. In the simple tandem mirror device, TMX, the drift cyclotron loss-cone (DCLC) mode was stabilized by plasma flow from the central cell into the end cell. However, to enhance the central-cell confinement and provide MHD stability, neutral beams were injected perpendicular to the magnetic field, which resulted in the excitation in the end cell of the Alfven ion-cyclotron (AIC) instability driven by plasma pressure and velocity distribution anisotropy. In the thermal-barrier experiment, TMX-U, the end-cell beams were injected at a 45/sup 0/ angle to the magnetic field to produce a sloshing-ion distribution, which is required to form the thermal barrier and the plugging potential. Ion distributions created by oblique injection were stable to the AIC mode and to the midplane (minimum magnetic field location) DCLC mode. However, an ion loss-cone instability remained at an axial location just outside the outboard peak of the sloshing-ion axial density profile, which is the density peak closest to the end wall. This mode can enhance the sloshing-ion loss rate, particularly at the lower levels of electron-cyclotron resonance heating (ECRH) used to form the thermal barrier. The stability to ion-cyclotron modes is critical to the performance of tandem mirrors and to designs for a mirror-based, high-fluence neutron source.

Casper, T.A.; Berzins, L.V.

1987-08-01

40

'Fairy Chimney'-shaped tandem metamaterials as double resonance SERS substrates.  

PubMed

A highly tunable design for obtaining double resonance substrates to be used in surface-enhanced Raman spectroscopy is proposed. Tandem truncated nanocones composed of Au-SiO(2)-Au layers are designed, simulated and fabricated to obtain resonances at laser excitation and Stokes frequencies. Surface-enhanced Raman scattering experiments are conducted to compare the enhancements obtained from double resonance substrates to those obtained from single resonance gold truncated nanocones. The best enhancement factor obtained using the new design is 3.86 × 10(7). The resultant tandem structures are named after "Fairy Chimneys" rock formation in Cappadocia, Turkey. PMID:23060087

Cinel, Neval A; Bütün, Serkan; Erta?, Gülay; Ozbay, Ekmel

2013-02-25

41

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

42

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

43

Enhance  

NSDL National Science Digital Library

It doesn't take a Photoshop expert to create attractive graphics for the Web. To prove this, the folks at MicroFrontier have released three graphic creation/editing packages for the Macintosh, each aimed at a different user level. All three applications support Photoshop 3.0 compatible plug-ins and basic features such as scanner support, image and resolution scaling, and basic image enhancement. Enhance, aimed at the graphics professionals, adds even more features, including multiple layers, opacity control, sixteen levels of undo, convolution filter effects, and CYMK support. A save-disabled demo version of each application is available at the MicroFrontier Website. The price for Enhance is $100 .

1998-01-01

44

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

45

Improved tandem mirror fusion reactor  

Microsoft Academic Search

It is shown that the introduction of barrier potentials between the plugs and solenoid of a tandem mirror substantially reduce ion energy and density required in end plugs. Several means for creating barriers and some of the important physics issues are discussed.

D. E. Baldwin; B. G. Logan

1979-01-01

46

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

47

Nanocrystal bilayer for tandem catalysis  

NASA Astrophysics Data System (ADS)

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; Habas, Susan E.; Soejima, Tetsuro; Aliaga, Cesar E.; Somorjai, Gabor A.; Yang, Peidong

2011-05-01

48

"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

49

Recent Activities at Tokai Tandem Accelerator  

SciTech Connect

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 {sup 8,9}Li 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 [Department of Research Reactor and Tandem Accelerator, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan)

2010-05-12

50

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

51

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

52

The construction of tandem dye-sensitized solar cells from chemically-derived nanoporous photoelectrodes  

NASA Astrophysics Data System (ADS)

A tandem dye-sensitized solar cell (tandem-DSSC) was synthesized on the basis of thin-film semiconductor electrodes. The nanoporous p-type NiO films were successfully obtained by simultaneous deposition of Al and Ni, followed by selective etching of Al and oxidation. Likewise, the n-type photoanode was made where Ag was etched in nitric acid after the initial formation of Ag/TiO2 nanocomposites. Such dye-sensitized photoelectrodes were combined to construct a tandem solar cell which exhibited an enhanced open-circuit voltage. Also, the tandem devices were subjected to various light fluxes to correlate the experimental cell parameters (open-circuit voltage, short-circuit current, fill factor, recombination shunt resistance, etc.) with the ideal one-diode model. Interestingly, impedance spectra of the tandem cell was well matched with the parameters from each of the n-type or p-type DSSC, indicative of successfully-designed tandem structure.

Choi, Hongsik; Hwang, Taehyun; Lee, Sangheon; Nam, Seunghoon; Kang, Joonhyeon; Lee, Byungho; Park, Byungwoo

2015-01-01

53

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

54

FABRICATION OF FUEL RODS BY TANDEM ROLLING  

Microsoft Academic Search

The tandem rolling process used industrially to manufacture tubular ; resistance heating elements was investigated to determine its applicability for ; fabricating rod-type fuel elements. Approximately 90 stainless steel clad fuel ; rods containing natural UOâ were tandem-rolled to establish optimum rolling ; parameters and fuel rod design. Fuel rod diameter, cladding wall thickness, UO\\/; sub 2\\/ particle size, rolling

Lingafelter

1961-01-01

55

Tandem junction amorphous silicon solar cells  

DOEpatents

An amorphous silicon solar cell has an active body with two or a series of layers of hydrogenated amorphous silicon arranged in a tandem stacked configuration with one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon arranged in tandem configuration can have the same bandgap or differing bandgaps.

Hanak, Joseph J. (Lawrenceville, NJ)

1981-01-01

56

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

57

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

58

Tandem Mirror Reactor Systems Code (Version I)  

SciTech Connect

A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.

Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.

1985-09-01

59

Advances in Tandem Mirror fusion power reactors  

Microsoft Academic Search

The Tandem Mirror exhibits several distinctive features which make the reactor embodiment of the principle very attractive: Simple low-technology linear central cell; steady-state operation; high-..beta.. operation; no driven current or disruptions; divertorless operation; direction conversion of end-loss power; low-surface heat loads; and advanced fusion fuel capability. In this paper, we examine these features in connection with two tandem mirror reactor

L. J. Perkins; B. G. Logan

1986-01-01

60

Phosphatidylcholine-specific phospholipase C and phospholipase D are respectively implicated in mitogen-activated protein kinase and nuclear factor kappaB activation in tumour-necrosis-factor-alpha-treated immature acute-myeloid-leukaemia cells.  

PubMed Central

Tumour necrosis factor-alpha (TNFalpha) has been reported to induce potent growth inhibition of committed myeloid progenitor cells, whereas it is a potential growth stimulator of human CD34(+)CD38(-) multipotent haematopoietic cells. The present study was aimed at evaluating the respective role of two phospholipases, phosphatidylcholine-specific phospholipase C (PC-PLC) and phospholipase D (PLD) in the response of the CD34(+) CD38(-) KG1a cells to TNFalpha. In these cells TNFalpha triggered phosphoinositide 3-kinase (PI3K)-dependent PC hydrolysis within 4-8 min with concomitant production of both diacylglycerol (DAG) and phosphocholine (P-chol). DAG and P-chol production was accompanied by extracellular-signal-related protein kinase-1 ('ERK-1') activation and DNA-synthesis stimulation. PC-PLC stimulation was followed by PI3K-independent PLD activation with concomitant phosphatidic acid (PA) production followed by PA-derived DAG accumulation and sustained nuclear factor kappaB (NF-kappaB) activation. PLD/NF-kappaB signalling activation played no role in the TNFalpha proliferative effect and conferred no consistent protection of KG1a cells towards antileukaemic agents. Altogether these results suggest that, in KG1a cells, TNFalpha can stimulate in parallel PC-PLC and PLD, whose lipid products activate in turn mitogen-activated protein kinase (MAP kinase) and NF-kappaB signalling respectively. Finally, our study suggests that PC-PLC, but not PLD, plays a role in the TNFalpha proliferative effect in immature myeloid cells. PMID:11023832

Plo, I; Lautier, D; Levade, T; Sekouri, H; Jaffrézou, J P; Laurent, G; Bettaïeb, A

2000-01-01

61

Lack of p53 Decreases Basal Oxidative Stress Levels in the Brain Through Upregulation of Thioredoxin-1, Biliverdin Reductase-A, Manganese Superoxide Dismutase, and Nuclear Factor Kappa-B  

PubMed Central

Abstract Aims: The basal oxidative and nitrosative stress levels measured in cytosol, mitochondria, and nuclei as well as in the whole homogenate obtained from the brain of wild type (wt) and p53 knockout [p53(?/?)] mice were evaluated. We hypothesized that the loss of p53 could trigger the activation of several protective mechanisms such as those involving thioredoxin-1 (Thio-1), the heme-oxygenase-1/biliverdin reductase-A (HO-1/BVR-A) system, manganese superoxide dismutase (MnSOD), the IkB kinase type ? (IKK?)/nuclear factor kappa-B (NF-kB), and the nuclear factor-erythroid 2 (NF-E2) related factor 2 (Nrf-2). Results: A decrease of protein carbonyls, protein-bound 4-hydroxy-2-nonenal (HNE), and 3-nitrotyrosine (3-NT) was observed in the brain from p53(?/?) mice compared with wt. Furthermore, we observed a significant increase of the expression levels of Thio-1, BVR-A, MnSOD, IKK?, and NF-kB. Conversely a significant decrease of Nrf-2 protein levels was observed in the nuclear fraction isolated from p53(?/?) mice. No changes were found for HO-1. Innovation: This is the first study of basal oxidative/nitrosative stress in in vivo conditions of brain obtained from p53(?/?) mice. New insights into the role of p53 in oxidative stress have been gained. Conclusion: We demonstrated, for the first time, that the lack of p53 reduces basal oxidative stress levels in mice brain. Due to the pivotal role that p53 plays during cellular stress response our results provide new insights into novel therapeutic strategies to modulate protein oxidation and lipid peroxidation having p53 as a target. The implications of this work are profound, particularly for neurodegenerative disorders. Antioxid. Redox Signal. 16, 1407–1420. PMID:22229939

Barone, Eugenio; Cenini, Giovanna; Sultana, Rukhsana; Di Domenico, Fabio; Fiorini, Ada; Perluigi, Marzia; Noel, Teresa; Wang, Chi; Mancuso, Cesare; St. Clair, Daret K.

2012-01-01

62

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

63

Ant search strategies after interrupted tandem runs.  

PubMed

Tandem runs are a form of recruitment in ants. During a tandem run, a single leader teaches one follower the route to important resources such as sources of food or better nest sites. In the present study, we investigate what tandem leaders and followers do, in the context of nest emigration, if their partner goes missing. Our experiments involved removing either leaders or followers at set points during tandem runs. Former leaders first stand still and wait for their missing follower but then most often proceed alone to the new nest site. By contrast, former followers often first engage in a Brownian search, for almost exactly the time that their former leader should have waited for them, and then former followers switch to a superdiffusive search. In this way, former followers first search their immediate neighbourhood for their lost leader before becoming ever more wide ranging so that in the absence of their former leader they can often find the new nest, re-encounter the old one or meet a new leader. We also show that followers gain useful information even from incomplete tandem runs. These observations point to the important principle that sophisticated communication behaviours may have evolved as anytime algorithms, i.e. procedures that are beneficial even if they do not run to completion. PMID:20435821

Franks, Nigel R; Richardson, Thomas O; Keir, Samantha; Inge, Stephen J; Bartumeus, Frederic; Sendova-Franks, Ana B

2010-05-01

64

Understanding tandem organic photovoltaic cell performance  

NASA Astrophysics Data System (ADS)

We develop a framework to understand the performance of tandem organic photovoltaic (OPV) cells consisting of a series-connected stack of an arbitrary number of sub-cells. The power conversion efficiency penalty, ??, is defined as the loss incurred when the tandem cell is at its maximum power point (MPP) but one or more sub-cells are not operating at their individual MPPs. To minimize ??, the current at the MPP for each sub-cell must be equal. We also develop a method to calculate the tandem cell spectral mismatch factor and fill factor, showing that they are related to both the fill factors and short circuit currents of all the constituent sub-cells. By including the current generated in the dark, exciton dissociation at the donor-acceptor heterojunction, and photoconductivity, along with current losses due to polaron-pair and bimolecular recombination, we simulate the operation of small molecule bilayer and mixed-layer sub-cells used in the tandem, and from these results derive the behavior of the integrated device. This analysis is used to understand and optimize tandem OPV cell performance.

Lassiter, Brian E.; Kyle Renshaw, C.; Forrest, Stephen R.

2013-06-01

65

Tandem mirror thermal barrier experimental program plan  

SciTech Connect

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

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

1980-01-02

66

High voltage series connected tandem junction solar battery  

DOEpatents

A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

Hanak, Joseph J. (Lawrenceville, NJ)

1982-01-01

67

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

68

Vacuum insulation tandem accelerator for B. Bayanov1  

E-print Network

-exchange tube in the center of high-voltage electrode, a proton beam is formed at the outlet of the tandem neutron therapy facility [1]. The main idea of tandem accelerator is providing high rate acceleration, as a powerful source of high voltage. Negative hydrogen ion beam is injected into electrostatic tandem

Taskaev, Sergey Yur'evich

69

Incorporating Peer Assessment into Tandem Learning  

ERIC Educational Resources Information Center

A credit-rated tandem course unit has been running at the University of Manchester for the past six years and an element of peer assessment has always been present in the assessment procedure. Unfortunately, the course leaders found that this element was not entirely satisfactory. Although there were clear criteria in the course documentation for…

Morley, John; Truscott, Sandra

2006-01-01

70

Micromorph tandem solar cells: optimization of the microcrystalline silicon bottom cell in a single chamber system  

NASA Astrophysics Data System (ADS)

We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 ?m. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.

Zhang, Xiao-Dan; Zheng, Xin-Xia; Xu, Sheng-Zhi; Lin, Quan; Wei, Chang-Chun; Sun, Jian; Geng, Xin-Hua; Zhao, Ying

2011-10-01

71

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

72

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

73

Probabilistic approaches to alignment with tandem repeats  

PubMed Central

Background Short tandem repeats are ubiquitous in genomic sequences and due to their complex evolutionary history pose a challenge for sequence alignment tools. Results To better account for the presence of tandem repeats in pairwise sequence alignments, we propose a simple tractable pair hidden Markov model that explicitly models their presence. Using the framework of gain functions, we design several optimization criteria for decoding this model and describe resulting decoding algorithms, ranging from the traditional Viterbi and posterior decoding to block-based decoding algorithms tailored to our model. We compare the accuracy of individual decoding algorithms on simulated and real data and find that our approach is superior to the classical three-state pair HMM. Conclusions Our study illustrates versatility of pair hidden Markov models coupled with appropriate decoding criteria as a modeling tool for capturing complex sequence features. PMID:24580741

2014-01-01

74

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

75

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

76

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

77

The metal interlayer in the charge generation layer of tandem organic light-emitting diodes  

NASA Astrophysics Data System (ADS)

This work studies the interface in the charge generation layer (CGL), consisting of aluminum (Al) doped in poly(ethylene glycol) dimethyl ether as an n-type layer and 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethane (F4-TCNQ) doped in N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine as an p-type layer, in tandem organic light-emitting diodes (OLEDs). Introducing a thin high work function metal interlayer (e.g., Ag or Au) effectively improves the transport and inhibits the accumulation of charges in the CGL, which markedly reduces the operating voltage and enhances the efficiency of tandem OLEDs. We attribute that the high density of surface states on metal clusters (interlayer) reduce the junction barrier to facilitate the transport of carriers through CGL. Experimental results show enhancements of tandem OLEDs by an additional metal interlayer as follows: luminous efficiency increases from 37.2 to 51.4 cd A-1, the light turn-on voltage decreases from 9.2 to 6.6 V, and luminescence at 10 mA cm-2 increases from 3712 to 5211 cd m-2.

Lee, Yu-Hao; Lin, Ming-Wei; Wen, Ten-Chin; Guo, Tzung-Fang

2013-10-01

78

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

79

TandEM: Titan and Enceladus mission  

NASA Astrophysics Data System (ADS)

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 (Montgolfière) and possibly several landing probes to be delivered through the atmosphere.

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.; Müller-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.; Bénilan, Y.; Bertucci, C.; Bézard, B.; Bjoraker, G. L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M. T.; Chassefière, 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.; Küppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le Mouélic, 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.; Menor Salvan, C.; Milillo, A.; Mitchell, D. G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, C. D.; Nixon, C. A.; Nna Mvondo, D.; 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.; Ruiz Bermejo, M.; 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, C.; Thissen, R.; Tomasko, M. G.; Toublanc, D.; Vali, H.; Vardavas, I.; Vuitton, V.; West, R. A.; Yelle, R.; Young, E. F.

2009-03-01

80

Effective optical path length for tandem diffuse cubic cavities as gas absorption cell  

NASA Astrophysics Data System (ADS)

Tandem diffuse cubic cavities designed by connecting two single diffuse cubic-shaped cavities, A and B, with an aperture (port fraction fap) in the middle of the connecting baffle was developed as a gas absorption cell. The effective optical path length (EOPL) was evaluated by comparing the oxygen absorption signal in the cavity and in air based on tunable diode laser absorption spectroscopy (TDLAS). Experimental results manifested an enhancement of EOPL for the tandem diffuse cubic cavities as the decrease of fap and can be expressed as the sum of EOPL of two single cubic cavities at fap < 0.01, which coincided well with theoretical analysis. The simulating EOPL was smaller than experimental results at fap > 0.01, which indicated that back scattering light from cavity B to cavity A cannot be ignored at this condition.

Yu, J.; Gao, Q.; Zhang, Y. G.; Zhang, Z. G.; Wu, S. H.

2014-12-01

81

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

...exogenous adjustments to the service band index for the interconnection...upward adjustments to the service band index for the tandem-switched...forth in paragraphs (j) and (k) of this section, telephone...38(b)(4) and 61.49(k) of this chapter; or...

2014-10-01

82

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

83

The capacity of digital links in tandem  

NASA Technical Reports Server (NTRS)

The present investigation is concerned with the error control strategy used in connection with digital data networks, taking into account the capacity of the end-to-end channel. It is assumed that the only source of noise is Gaussian and that bandwidth limitation on capacity can be ignored. Attention is given to L links in tandem with binary repeaters, the asymptotic capacity with a large number of links, some alternative repeater strategies, and approaches for lowering the bit error probability. Numerical results are presented, taking into consideration capacity versus link error probability for various numbers of links.

Posner, E. C.; Rubin, A. L.

1984-01-01

84

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

85

Method of fabricating bifacial tandem solar cells  

SciTech Connect

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

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

2014-10-07

86

Some new ideas for Tandem Mirror blankets  

SciTech Connect

The Tandem Mirror Reactor, with its cylindrical central cell, has led to numerous blanket designs taking advantage of the simple geometry. Also many new applications for fusion neutrons are now being considered. To the pure fusion electricity producers and hybrids producing fissile fuel, we are adding studies of synthetic fuel producers and fission-suppressed hybrids. The three blanket concepts presented are new ideas and should be considered illustrative of the breadth of Livermore's application studies. They are not meant to imply fully analyzed designs.

Neef, W.S. Jr.

1981-10-12

87

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

88

Potential of optical design in tandem micromorph silicon solar cells  

NASA Astrophysics Data System (ADS)

The potential of three advanced optical designs in tandem micromorph silicon solar cells are analysed by means of optical simulations: enhanced light scattering, intermediate reflector (interlayer) and antireflective coating (ARC) on glass. The effects on quantum efficiency, QE, and short circuit current density, J SC, of the top and bottom cell are investigated. In case of enhanced light scattering, the role of haze parameter and angular distribution function of scattered light is analysed separately. High haze parameter improves light trapping in top and bottom cell. However, the improvement in QE and J SC of the bottom cell is limited at higher haze parameters due to increased absorption in top cell and increased optical losses in realistic textured ZnO/Ag back contact. Broad ADF plays an important role for improving the performances of both, top and bottom cell. The role of refractive index of an interlayer between top and bottom cell is analysed. Significant increases in QE and J SC of the top cell are revealed for small refractive indexes of the interlayer (n < 2.0). At the same time noticeable decrease in the performance of the bottom cell is observed. Optimisation of thickness and refractive index of a single-layer ARC on glass is carried out in order to obtain maximal J SC either in top or in bottom cell. Moderate increases in J SC and QE are obtained for optimised ARC parameters. Among the three optical designs, the greatest potential, considering the improvements in both cells, is revealed for enhanced light scattering.

Krc, J.; Campa, A.; Smole, F.; Topic, M.

2006-04-01

89

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

90

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

91

The Bucharest FN Tandem Accelerator: Modernization and Development  

NASA Astrophysics Data System (ADS)

The Bucharest FN tandem accelerator, installed in 1973 and upgraded in 1983 to 9 MV, has been used for atomic and nuclear physics studies as well as for different applications using accelerated ion beams. In the last three years a program of modernization of the tandem accelerator including the replacement of the old accelerator equipment by new ones, installation of a pelletron system for the Van de Graaff generator and installation of new negative ion injectors was undertaken. In parallel a development of the tandem accelerator was started. In 2009, a beam pulsing system in the nanosecond range is scheduled to be installed. All these works aimed to transform the tandem accelerator in a reliable and efficient tool for research and applications are presented. The main lines of the research program at the Bucharest tandem accelerator are shortly presented too.

Dobrescu, S.; Mosu, D. V.; Moisa, D.; Papureanu, S.

2009-03-01

92

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

93

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

94

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

95

Quantitative analysis of sirolimus (Rapamycin) in blood by high-performance liquid chromatography–electrospray tandem mass spectrometry  

Microsoft Academic Search

We report here a quantitative method for the analysis of sirolimus in blood using solid-phase sample preparation and HPLC–electrospray-tandem mass spectrometry detection. Blood samples (500 ?l) were prepared by pre-treatment with acetonitrile: 15 mM zinc sulphate (70:30, v\\/v), containing 32-demethoxysirolimus (internal standard) and C18 solid-phase extraction. The electrospray conditions were chosen to enhance the [M+NH4]+ species at the expense of

Paul J Taylor; Anthony G Johnson

1998-01-01

96

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

97

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

SciTech Connect

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

Hamilton, G.W.

1980-09-25

98

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

99

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

100

Parametric systems analysis for tandem mirror hybrids  

SciTech Connect

Fusion fission systems, consisting of fissile producing fusion hybrids combining a tandem mirror fusion driver with various blanket types and net fissile consuming LWR's, have been modeled and analyzed parametrically. Analysis to date indicates that hybrids can be competitive with mined uranium when U/sub 3/O/sub 8/ cost is about 100 $/lb., adding less than 25% to present day cost of power from LWR's. Of the three blanket types considered, uranium fast fission (UFF), thorium fast fission (ThFF), and thorium fission supressed (ThFS), the ThFS blanket has a modest economic advantage under most conditions but has higher support ratios and potential safety advantages under all conditions.

Lee, J.D.; Chapin, D.L.; Chi, J.W.H.

1980-09-01

101

The construction of tandem dye-sensitized solar cells from chemically-derived nanoporous photoelectrodes  

E-print Network

Nanoporous electrode a b s t r a c t A tandem dye-sensitized solar cell (tandem-DSSC) was synthesized-type DSSC, indicative of successfully-designed tandem structure. © 2014 Elsevier B.V. All rights reserved. 1, the concept of `tandem- DSSC' has started evolving where both working and counter elec- trodes in the DSSC

Park, Byungwoo

102

Recent Activities in Tandem, Booster and TRIAC at Tokai  

SciTech Connect

Present status and recent developments of the tandem accelerator, superconducting booster, and radioactive nuclear beam accelerator TRIAC 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 noble-gas ions. A superconducting cavity for low-velocity ions was developed. Radioactive nuclear beams of {sup 8}Li, {sup 123}In, and {sup 143}Ba were accelerated. Recent experimental results of nuclear physics are also reported.

Ishii, Tetsuro; Matsuda, Makoto; Kabumoto, Hiroshi; Osa, Akihiko [Department of Research Reactor and Tandem Accelerator, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan)

2009-05-04

103

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

104

The Bucharest Tandem Accelerator - part of the European Infrastructure  

SciTech Connect

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

Zamfir, Nicolae Victor [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box Mg-6, Bucharest-Magurele (Romania)

2007-04-23

105

Argonne tandem as injector to a superconducting linac  

SciTech Connect

The Argonne Tandem uses Pelletron chains, NEC accelerator tubes, and a dual closed-corona system. Its main function is to be an injector for a superconducting linear accelerator. As long as the transverse and longitudinal emittances are within the acceptance of the linac, the output beam quality of the tandem-linac system is essentially determined by the tandem. The sensitivity of the linac to the longitudinal emittance ..delta..E..delta..t of the incident beam makes the output beam quality dependent on the negative-ion velocity distribution in the source, transit-time effects in the tandem, molecular-beam dissociation, and stripper-foil uniformity. This paper discusses these beam-degrading effects.

Yntema, J.L.; Den Hartog, P.K.; Henning, W.; Kutschera, W.

1980-01-01

106

INTEGRATED TANDEM ELECTROABSORPTION MODULATORS FOR HIGH-SPEED OTDM APPLICATIONS  

E-print Network

INTEGRATED TANDEM ELECTROABSORPTION MODULATORS FOR HIGH-SPEED OTDM APPLICATIONS Volkan Kaman, Yi of California, Santa Barbara, CA 93106, USA Tel: 1-805-893-4883 Fax: 1-805-893-3262 (kaman@opto.ucsb.edu) Sheng

Bowers, John

107

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

108

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

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

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

109

NTRFinder: a software tool to find nested tandem repeats  

PubMed Central

We introduce the software tool NTRFinder to search for a complex repetitive structure in DNA we call a nested tandem repeat (NTR). An NTR is a recurrence of two or more distinct tandem motifs interspersed with each other. We propose that NTRs can be used as phylogenetic and population markers. We have tested our algorithm on both real and simulated data, and present some real NTRs of interest. NTRFinder can be downloaded from http://www.maths.otago.ac.nz/~aamatroud/. PMID:22121222

Matroud, Atheer A.; Hendy, M. D.; Tuffley, C. P.

2012-01-01

110

Advanced high-efficiency concentrator tandem solar cells  

Microsoft Academic Search

Computer modeling studies of two-junction concentrator tandem solar cells show that infrared (IR)-responsive bottom cells are essential to achieve the highest performance levels in both terrestrial and space applications. These studies also show that medium-bandgap\\/low-bandgap tandem pairs hold a clear performance advantage under concentration when compared to high-bandgap\\/medium-bandgap pairs, even at high operating temperatures (up to 100°C). Consequently, two novel

M. W. Wanlass; T. J. Coutts; J. S. Ward; K. A. Emery; T. A. Gessert; C. R. Osterwald

1991-01-01

111

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

112

Intragenic tandem repeat variation between Legionella pneumophila strains  

PubMed Central

Background Bacterial genomes harbour a large number of tandem repeats, yet the possible phenotypic effects of those found within the coding region of genes are only beginning to be examined. Evidence exists from other organisms that these repeats can be involved in the evolution of new genes, gene regulation, adaptation, resistance to environmental stresses, and avoidance of the immune system. Results In this study, we have investigated the presence and variability in copy number of intragenic tandemly repeated sequences in the genome of Legionella pneumophila, the etiological agent of a severe pneumonia known as Legionnaires' disease. Within the genome of the Philadelphia strain, we have identified 26 intragenic tandem repeat sequences using conservative selection criteria. Of these, seven were "polymorphic" in terms of repeat copy number between a large number of L. pneumophila serogroup 1 strains. These strains were collected from a wide variety of environments and patients in several geographical regions. Within this panel of strains, all but one of these seven genes exhibited statistically different patterns in repeat copy number between samples from different origins (environmental, clinical, and hot springs). Conclusion These results support the hypothesis that intragenic tandem repeats could play a role in virulence and adaptation to different environments. While tandem repeats are an increasingly popular focus of molecular typing studies in prokaryotes, including in L. pneumophila, this study is the first examining the difference in tandem repeat distribution as a function of clinical or environmental origin. PMID:19077205

Coil, David A; Vandersmissen, Liesbeth; Ginevra, Christophe; Jarraud, Sophie; Lammertyn, Elke; Anné, Jozef

2008-01-01

113

Flavonoid profile in soybeans by high-performance liquid chromatography/tandem mass spectrometry.  

PubMed

Flavonoid profiling of a soybean sample has been performed by liquid chromatography/positive electrospray tandem mass spectrometry (LC/ESI(+)-MS/MS) using a quadrupole-linear ion trap (QLIT) instrument with an information-dependent data acquisition (IDA) protocol that looped, in a single run, an enhanced MS scan and an enhanced product ion scan. As compromise between time and obtainable information, spectra acquisition was split into two distinct runs: 220-450 Th and 400-800 Th, respectively. The isoflavones daidzein and genistein were identified as aglycones, monoglycosides, diglycosides, triglycosides, acetylglycosides, malonylglycosides, malonyl diglycosides, and dimalonyl diglycosides, whereas glycitein triglycosides, acetylglycosides, and dimalonyl diglycosides were not detected. Also kaempferol di- and triglycosides, malonylglycosides and malonyl diglycosides, previously reported in soy leaves and pods, and four naringenin malonylglycosides were identified. PMID:17569102

Cavaliere, Chiara; Cucci, Francesca; Foglia, Patrizia; Guarino, Chiara; Samperi, Roberto; Laganà, Aldo

2007-01-01

114

Aconitum pseudo-laeve var. erectum inhibits receptor activator of nuclear factor kappa-B ligand-induced osteoclastogenesis via the c-Fos/nuclear factor of activated T-cells, cytoplasmic 1 signaling pathway and prevents lipopolysaccharide-induced bone loss in mice.  

PubMed

Aconitum pseudo-laeve var. erectum (APE) has been widely shown in herbal medicine to have a therapeutic effect on inflammatory conditions. However, there has been no evidence on whether the extract of APE is involved in the biological bone metabolism process, particularly osteoclast-mediated bone resorption. In this study, we confirmed that the administration of APE could restore normal skeletal conditions in a murine model of lipopolysaccharide (LPS)-induced bone loss via a decrease in the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio and osteoclast number. We then investigated the effect of APE on the RANKL-induced formation and function of osteoclasts to elucidate its underlying molecular mechanisms. APE suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive cells, as well as the bone-resorbing activity of mature osteoclasts. Furthermore, APE attenuated nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and c-Fos without affecting any early signal pathway of osteoclastogenesis. Subsequently, APE significantly downregulated the expression of various genes exclusively expressed in osteoclasts. These results demonstrate that APE restores LPS-induced bone loss through a decrease of the serum RANKL/OPG ratio, and inhibits osteoclast differentiation and function, suggesting the promise of APE as a potential cure for various osteoclast-associated bone diseases. PMID:25100255

Baek, Jong Min; Kim, Ju-Young; Cheon, Yoon-Hee; Park, Sun-Hyang; Ahn, Sung-Jun; Yoon, Kwon-Ha; Oh, Jaemin; Lee, Myeung Su

2014-01-01

115

Landmarks and ant search strategies after interrupted tandem runs.  

PubMed

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

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

2014-03-15

116

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

117

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

118

Dynamic analysis of FPSO with a tandem offloading system  

SciTech Connect

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

Nishimoto, K.; Brinati, H.L.; Fucatu, C.H. [Univ. of Sao Paulo (Brazil). Dept. of Naval Architecture and Ocean Engineering

1996-12-31

119

Parallel Tandems of Dye Sensitized Solar Cells with CNT Collector  

NASA Astrophysics Data System (ADS)

In this presentation, we demonstrate the fabrication of monolithic parallel tandem dye sensitized solar cells using a semitransparent layer of carbon nanotubes. Each DSC sub-cell has titania photoelectrode with two different dyes: N 719 and N 749, which absorb light in different parts of solar spectrum. This layer of carbon nanotubes laminated on highly porous polymeric Millipore filter acts as both the collector of charge carrier and as the catalyst of the I/I3^- redox reaction that completes the function of the cell, overall allowing easier fabrication for tandem solar cell devices, with a potential for creating flexible devices in the future. The parallel tandem shows the total photocurrent which is nearly the sum of two Isc currents of constituent cells, and total Voc, which is average of two Voc, while conventional in-series DSC tandems show the lowest Voc and slightly increased Isc[1]. Thus the higher efficiency can be achieved in parallel DSC tandems, and we discuss the physical reasons for this effect. [1] Yanagida, et.al. J. of Photochemistry and Photobiology A: Chemistry Volume 164, Issues 1-3, 1 June 2004, Pages 33-39

Velten, Josef; Yuan, Chao-Chen; Zakhidov, Anvar

2009-03-01

120

The design and numerical analysis of tandem thermophotovoltaic cells  

NASA Astrophysics Data System (ADS)

In this paper, numerical analysis of GaSb =(Eg = 0.72 eV)/Ga0.84In0.16As0.14Sb0.86 (Eg = 0.53 eV) tandem thermophotovoltaic (TPV) cells is carried out by using Silvaco/Atlas software. In the tandem cells, a GaSb p-n homojunction is used for the top cell and a GaInAsSb p-n homojunction for the bottom cell. A heavily doped GaSb tunnel junction connects the two sub-cells together. The simulations are carried out at a radiator temperature of 2000 K and a cell temperature of 300 K. The radiation photons are injected from the top of the tandem cells. Key properties of the single- and dual-junction TPV cells, including I-V characteristic, maximum output power (Pmax), open-circuit voltage (Voc), short-circuit current (Isc), etc. are presented. The effects of the sub-cell thickness and carrier concentration on the key properties of tandem cells are investigated. A comparison of the dual-TPV cells with GaSb and GaInAsSb single junction cells shows that the Pmax of tandem cells is almost twice as great as that of the single-junction cells.

Yang, Hao-Yu; Liu, Ren-Jun; Wang, Lian-Kai; Lü, You; Li, Tian-Tian; Li, Guo-Xing; Zhang, Yuan-Tao; Zhang, Bao-Lin

2013-10-01

121

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

122

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

123

Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors.  

PubMed

Thin-film silicon tandem solar cells are composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell, stacked and connected in series. In order to match the photocurrents of the top cell and the bottom cell, a proper photon management is required. Up to date, single-layer intermediate reflectors of limited spectral selectivity are applied to match the photocurrents of the top and the bottom cell. In this paper, we design and prototype multilayer intermediate reflectors based on aluminum doped zinc oxide and doped microcrystalline silicon oxide with a spectrally selective reflectance allowing for improved current matching and an overall increase of the charge carrier generation. The intermediate reflectors are successfully integrated into state-of-the-art tandem solar cells resulting in an increase of overall short-circuit current density by 0.7 mA/cm(2) in comparison to a tandem solar cell with the standard single-layer intermediate reflector. PMID:25322181

Hoffmann, Andre; Paetzold, Ulrich W; Zhang, Chao; Merdzhanova, Tsvetelina; Lambertz, Andreas; Ulbrich, Carolin; Bittkau, Karsten; Rau, Uwe

2014-08-25

124

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

125

Properties of tandem balloons connected by extendable suspension wires  

NASA Astrophysics Data System (ADS)

It is well known that tandem balloons have interesting properties, for example, a combination of a zero-pressure balloon and a super-pressure balloon which withstands high pressure can achieve the long-duration flight against the difference of the day-night temperature. Here, we studied the response of tandem balloons when we change the length of the suspension rope. For example, a tandem balloon with a large zero-pressure balloon and a small superpressure balloon, one can change the floating altitude of the zero-pressure balloon without changing the altitude of the supper-pressure balloon. We are going to show our results of the properties based on analytic calculation.

Saito, Yoshitaka

126

A tandem mirror plasma source for hybrid plume plasma studies  

NASA Technical Reports Server (NTRS)

A tandem mirror device to be considered as a hot plasma source for the hybrid plume rocket concept is discussed. The hot plamsa from this device is injected into an exhaust duct, which will interact with an annular hypersonic layer of neutral gas. The device can be used to study the dynamics of the hybrid plume, and to verify the numerical predictions obtained with computer codes. The basic system design is also geared towards low weight and compactness, and high power density at the exhaust. The basic structure of the device consists of four major subsystems: (1) an electric power supply; (2) a low temperature, high density plasma gun, such as a stream gun, an MPD source or gas cell; (3) a power booster in the form of a tandem mirror machine; and (4) an exhaust nozzle arrangement. The configuration of the tandem mirror section is shown.

Yang, T. F.; Chang, F. R.; Miller, R. H.; Wenzel, K. W.; Krueger, W. A.

1985-01-01

127

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

128

Silicon based tandem cells: novel photocathodes for hydrogen production.  

PubMed

A photovoltaic tandem cell made of amorphous silicon (a-Si) and microcrystalline silicon (?c-Si) was investigated as a photocathode for hydrogen evolution in a photoelectrochemical device. The electronic and electrochemical properties of the samples were characterized using X-ray photoemission spectroscopy (XPS) and cyclic voltammetry (CV), whereas the morphology of the surface in contact with the electrolyte was investigated by scanning electron microscopy (SEM). The electric efficiency of the tandem cell was determined to be 5.2% in a photoelectrochemical (PEC) setup in acidic solution which is only about half of the photovoltaic efficiency of the tandem cell. A significant improvement in efficiency was achieved with platinum as a catalyst which was deposited by physical vapour deposition (PVD) under ultra-high vacuum (UHV) conditions. PMID:24710175

Calvet, W; Murugasen, E; Klett, J; Kaiser, B; Jaegermann, W; Finger, F; Hoch, S; Blug, M; Busse, J

2014-06-28

129

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

130

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

131

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

132

Tandem riboswitch architectures exhibit complex gene control functions.  

PubMed

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

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

2006-10-13

133

Tandem catalysis of amines using porous graphene oxide.  

PubMed

Porous graphene oxide can be used as a metal-free catalyst in the presence of air for oxidative coupling of primary amines. Herein, we explore a GO-catalyzed carbon-carbon or/and carbon-heteroatom bond formation strategy to functionalize primary amines in tandem to produce a series of valuable products, i.e., ?-aminophosphonates, ?-aminonitriles, and polycyclic heterocompounds. Furthermore, when decorated with nano-Pd, the Pd-coated porous graphene oxide can be used as a bifunctional catalyst for tandem oxidation and hydrogenation reactions in the N-alkylation of primary amines, achieving good to excellent yields under mild conditions. PMID:25551171

Su, Chenliang; Tandiana, Rika; Balapanuru, Janardhan; Tang, Wei; Pareek, Kapil; Nai, Chang Tai; Hayashi, Tamio; Loh, Kian Ping

2015-01-21

134

Tandem Cycloisomerization/Suzuki Coupling of Arylethynyl MIDA Boronates  

PubMed Central

A tandem gold-catalyzed cycloisomerization/Suzuki cross coupling sequence involving arylethynyl-N-methyliminodiacetic acid boronates is described. Combining the mildness of homogeneous gold catalysis with the versatility of N-methyliminodiacetic acid (MIDA) boronates, this tandem two-step method enables the rapid assembly of various aryl-substituted heterocycles without having to isolate or purify any heterocyclic MIDA boronate intermediates. Another major advantage of this method is that a wide range of heterocycles bearing different aryl groups may be made from a single MIDA boronate alkyne precursor. PMID:21765556

Chan, Julian M. W.; Amarante, Giovanni W.; Toste, F. Dean

2011-01-01

135

Speeding up tandem mass spectral identification using indexes  

PubMed Central

Motivation: Tandem mass spectrometry (MS/MS) has been routinely used in proteomics studies. Post-translational modification (PTM) identification is a challenging problem in tandem mass spectral analysis. Results: In this article, we define two scoring functions for identifying peptides/proteins with PTMs from MS/MS spectra: match scores and diagonal scores, as well as two spectral identification problems based on the two scores. We propose several index-based algorithms for the two problems. Both theoretical and experimental analyses show that the index-based algorithms significantly improve on speed when compared with existing algorithms. Contact: xil018@cs.ucsd.edu PMID:22543365

Liu, Xiaowen; Mammana, Alessandro; Bafna, Vineet

2012-01-01

136

The Time-to-Empty for Tandem Jackson Michael A. Zazanis  

E-print Network

The Time-to-Empty for Tandem Jackson Networks Michael A. Zazanis Department of Statistics Athens Abstract We derive the distribution of the time-to-empty for an open tandem Jackson network assuming that Jackson network. The results obtained are used in the analysis of a two-class tandem Jackson network

Zazanis, Michael A.

137

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

2014-12-01

138

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.

139

C60/N,N?-bis(1-naphthyl)-N,N?-diphenyl-1,1?-biphenyl-4,4?-diamine:MoO3 as the interconnection layer for high efficient tandem blue fluorescent organic light-emitting diodes  

PubMed Central

The high efficient tandem blue fluorescent organic light emitting diodes (OLEDs) with the transparent interconnection layer (ICL) of fullerence (C60)/Molybdenum oxide (MoO3)-doped N,N?-bis(1-naphthyl)-N,N?-diphenyl-1,1?-biphenyl-4,4?-diamine (NPB) were presented. A stack consisting of 0.5?nm of LiF and 1?nm of Ca, which is located from C60 to adjacent electron transporting layer is used as an electron injection layer. The experiment results indicate that the luminance of the tandem device is basically equal to that of the traditional single-unit device, but the current density of the tandem device is much less than that of the single-unit device under a same luminance. The current efficiency and the maximal power efficiency of tandem device with LiF/Ca/C60/NPB:MoO3/MoO3-based interconnection layer have been approximately enhanced by 250% and 126%, respectively. In addition, we also analyze that the mechanism of the efficiency enhancement is ascribed to the effective charge separation and transport of the ICL in tandem OLEDs. PMID:23861554

Wu, Xiaoming; Bi, Wentao; Hua, Yulin; Sun, Jin'e; Xiao, Zhihui; Wang, Li; Yin, Shougen

2013-01-01

140

Improving the efficiency of thin film tandem solar cells by plasmonic intermediate reflectors  

NASA Astrophysics Data System (ADS)

Thin film tandem solar cells made of amorphous and microcrystalline silicon provide renewable energy at the benefit of low material consumption. As a drawback, these materials do not posses the high carrier mobilities of their crystalline counterpart which limits the feasible material thickness. For maintaining the light absorption as high as possible, photon management is required. Here we show that metallic nanodiscs that sustain localized plasmon polaritons can increase the efficiency of such solar cells if they are incorporated into the dielectric intermediate reflector separating the top and the bottom cell. We provide quantitative estimates for the possible absorption enhancement of optimized bi-periodic nanodiscs that are feasible for fabrication. Emphasis is also put on discussing the impact of obliquely incident sun light on the solar cell performance.

Fahr, Stephan; Rockstuhl, Carsten; Lederer, Falk

2010-09-01

141

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

142

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

PubMed

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. PMID:25101717

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

2014-08-29

143

Detection of anabolic steroids in dietary supplements: The added value of an androgen yeast bioassay in parallel with a liquid chromatography–tandem mass spectrometry screening method  

Microsoft Academic Search

Recently we constructed a recombinant yeast cell that expresses the human androgen receptor (hAR) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to androgens. When exposed to testosterone, the concentration where half-maximal activation is reached (EC50) was 50nM. Eighteen different dietary supplements, already analysed by a liquid chromatography–tandem mass spectrometry method (LC–MS\\/MS) for the presence of anabolic

Jeroen C. W. Rijk; Toine F. H. Bovee; Si Wang; Christof Van Poucke; Carlos Van Peteghem; Michel W. F. Nielen

2009-01-01

144

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

145

Bio-olefins from unsaturated fatty acids via tandem catalysis  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

146

Tandem metal relay catalysis: from cyclopropene to polysubstituted furan.  

PubMed

Transmetalation is a key step in traditional coupling reactions. Herein we discuss the most recent progress in the metal-metal relay catalysis based on a transmetalation strategy. An efficient synthetic strategy for the formation of polysubstituted furan derivatives from cyclopropenes based on the tandem metal relay catalysis (TMRC reaction) is summarized. PMID:24962613

Song, Chuanling; Wang, Jianwu; Xu, Zhenghu

2014-08-21

147

Gold-catalyzed tandem cycloisomerization-hydroalkoxylation of homopropargylic alcohols.  

PubMed

The tandem cycloisomerization-hydroalkoxylation of various homopropargylic alcohols in the presence of an alcohol and a dual catalyst system, consisting of a gold precatalyst and a Brønsted acid, provides an efficient route to tetrahydrofuranyl ethers under mild reaction conditions. The reaction can be carried out in various solvents, including alcohol, with both terminal and internal alkynes as the substrate. PMID:16986932

Belting, Volker; Krause, Norbert

2006-09-28

148

Dynamics of tandem bubble interaction in a microfluidic channel.  

PubMed

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

2011-11-01

149

Optimal computation of all tandem repeats in a weighted sequence  

PubMed Central

Background Tandem duplication, in the context of molecular biology, occurs as a result of mutational events in which an original segment of DNA is converted into a sequence of individual copies. More formally, a repetition or tandem repeat in a string of letters consists of exact concatenations of identical factors of the string. Biologists are interested in approximate tandem repeats and not necessarily only in exact tandem repeats. A weighted sequence is a string in which a set of letters may occur at each position with respective probabilities of occurrence. It naturally arises in many biological contexts and provides a method to realise the approximation among distinct adjacent occurrences of the same DNA segment. Results Crochemore’s repetitions algorithm, also referred to as Crochemore’s partitioning algorithm, was introduced in 1981, and was the first optimal O(nlogn)-time algorithm to compute all repetitions in a string of length n. In this article, we present a novel variant of Crochemore’s partitioning algorithm for weighted sequences, which requires optimal O(nlogn) time, thus improving on the best known On2-time algorithm (Zhang et al., 2013) for computing all repetitions in a weighted sequence of length n. PMID:25221616

2014-01-01

150

Molecular Cell Autoregulation of the Rsc4 Tandem  

E-print Network

Molecular Cell Article Autoregulation of the Rsc4 Tandem Bromodomain by Gcn5 Acetylation Andrew P. Endogenous Rsc4 is acetylated only at K25, and Gcn5 is identified as necessary and sufficient for Rsc4 K25 of Rsc4 K25 results in altered growth rates. These data suggest an autoregulatory mechanism in which Gcn5

Hill, Chris

151

The Tandem-RFQ Linac Booster at Sandia National Laboratories  

Microsoft Academic Search

A booster linac based on the Radio Frequency Quadrupole (RFQ linac) has been put into routine operation on the 6.5 MV EN tandem accelerator at the Sandia National Laboratories (SNL) Ion Beam Materials Research Lab (IBMRL) for Radiation Effects Microscopy (REM) experiments with high energy, heavy ion beams. The booster linac consists of two RFQ stages that accelerate heavy ions

F. D. McDaniel; B. L. Doyle; D. L. Buller; R. W. Hamm; Kirtland AFB

152

The Tandem-RFQ Linac Booster at Sandia National Laboratories  

Microsoft Academic Search

A booster linac based on the Radio Frequency Quadrupole (RFQ linac) has been put into routine operation on the 6.5 MV EN tandem accelerator at the Sandia National Laboratories (SNL) Ion Beam Materials Research Lab (IBMRL) for Radiation Effects Microscopy (REM) experiments with high energy, heavy ion beams. The booster linac consists of two RFQ stages that accelerate heavy ions

F. D. McDaniel; B. L. Doyle; P. Rossi; D. L. Buller; R. W. Hamm; H. Schone

2003-01-01

153

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

154

Computing Positional Isotopomer Distributions from Tandem Mass Spectrometric Data  

Microsoft Academic Search

The isotopomer distributions of metabolites are invaluable pieces of information in the computation of the flux distribution in a metabolic network. We describe the use of tandem mass spectrometry with the daughter ion scanning technique in the discovery of positional isotopomer distributions (PID). This technique increases the possibilities of mass spectrometry since given the same fragment ions, it uncovers more

Ari Rantanen; Juho Rousu; Juha T. Kokkonen; Virpi Tarkiainen; Raimo A. Ketola

2002-01-01

155

Tandem Fan Applications in Advanced STOVL Fighter Configurations  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

156

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

157

?-BaB 2O 4 deep UV monolithic walk-off compensating tandem  

NASA Astrophysics Data System (ADS)

The generation of watt-level cw narrow-linewidth sources at specific deep-UV wavelengths corresponding to atomic cooling transitions usually employs external cavity-enhanced second-harmonic generation (SHG) of moderate-power visible lasers in birefringent materials. Among the oxo-borate materials, barium borate (?-BaB 2O 4 or BBO) combines the highest UV band edge and largest nonlinearity but suffers from large walk-off angles that limits the nonlinear interaction length. Alternative quasi-phase-matched (QPM) ferroelectrics are hardly suited for cavity-enhanced operation due to their much larger UV absorption and associated photo-refractive and thermal lensing effects, in addition to the difficult fabrication of fine-pitch domain gratings for short UV coherence lengths. In this work, we investigate an alternative approach to cw deep-UV generation by employing the low-loss BBO in a monolithic walk-off compensating structure [J.-J. Zondy, Ch. Bonnin, D. Lupinski, J. Opt. Soc. Am. B 20 (2003) 1675] to simultaneously enhance the effective nonlinear coefficient while minimizing the UV beam ellipticity under tight focusing. As a preliminary step to cavity-enhanced operation, and in order to apprehend the design difficulties stemming from the extremely low acceptance angle of BBO, we investigate and analyze the single-pass performance of a Lc = 8 mm monolithic walk-off compensating structure made of 2 optically-contacted BBO plates cut for type-I critically phase-matched SHG of a cw ? = 570.4 nm dye laser. As compared with a bulk crystal of identical length, a sharp UV efficiency enhancement factor of 1.65 has been evidenced with the tandem structure, but at ˜-1 nm from the targeted fundamental wavelength, highlighting the sensitivity of this technique when applied to a highly birefringent material such as BBO. Solutions to angle cut residual errors are identified so as to match accurately more complex periodic-tandem structure performance to any target UV wavelength, opening the prospect for high-power, good beam quality deep-UV cw laser sources for atom cooling and trapping.

Friebe, J.; Moldenhauer, K.; Rasel, E. M.; Ertmer, W.; Isaenko, L.; Yelisseyev, A.; Zondy, J.-J.

2006-05-01

158

Development of an advanced spacecraft tandem mass spectrometer  

NASA Astrophysics Data System (ADS)

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.

1992-03-01

159

TRedD--a database for tandem repeats over the edit distance.  

PubMed

A 'tandem repeat' in DNA is a sequence of two or more contiguous, approximate copies of a pattern of nucleotides. Tandem repeats are common in the genomes of both eukaryotic and prokaryotic organisms. They are significant markers for human identity testing, disease diagnosis, sequence homology and population studies. In this article, we describe a new database, TRedD, which contains the tandem repeats found in the human genome. The database is publicly available online, and the software for locating the repeats is also freely available. The definition of tandem repeats used by TRedD is a new and innovative definition based upon the concept of 'evolutive tandem repeats'. In addition, we have developed a tool, called TandemGraph, to graphically depict the repeats occurring in a sequence. This tool can be coupled with any repeat finding software, and it should greatly facilitate analysis of results. Database URL: http://tandem.sci.brooklyn.cuny.edu/ PMID:20624712

Sokol, Dina; Atagun, Firat

2010-01-01

160

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

161

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

162

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

163

Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry of Carotenoids  

PubMed Central

Carotenoids are natural pigments synthesized by plants and photosynthetic microorganisms, some of which, like ?-carotene, are precursors of vitamin A, and others such as lutein and lycopene might function in the prevention of age-related macular degeneration and prostate cancer, respectively. Mass spectrometry provides high sensitivity and selectivity for the identification and quantitative analysis of carotenoids in biological samples, and previous studies have described how atmospheric pressure chemical ionization (APCI) offers distinct advantages over electrospray and fast atom bombardment for the analysis of specific carotenoids. Since APCI product ion tandem mass spectra have been reported for only a few carotenoids, a detailed investigation of twelve carotenes and xanthophylls was carried out using both positive ion and negative ion APCI tandem mass spectrometry with collision-induced dissociation. Using protonated molecules as precursor ions in positive ion mode and radical anions in negative ion mode, characteristic fragment ions were identified that may be used to distinguish between carotenoids. PMID:22408388

van Breemen, Richard B.; Dong, Linlin; Pajkovic, Natasa D.

2011-01-01

164

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

165

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

166

Fluorescent tandem phycobiliprotein conjugates. Emission wavelength shifting by energy transfer.  

PubMed Central

A fluorescent tandem phycobiliprotein conjugate with a large Stokes shift was prepared by the covalent attachment of phycoerythrin to allophycocyanin. The efficiency of energy transfer from phycoerythrin to allophycocyanin in this disulfide-linked conjugate was 90%. A distinctive feature of this phycocyanin conjugate is the wide separation between the intense absorption maximum of phycoerythrin (epsilon = 2.4 x 10(6) cm-1 M-1 at 545 nm) and the fluorescence emission maximum of allophycocyanin (660 nm). Energy transfer from a donor to a covalently attached acceptor can be used to adjust the magnitude of the Stokes shift. Tandem phycobiliprotein conjugates can be used to advantage in fluorescence-activated cell sorting, fluorescence microscopy, and fluorescence immunoassay analyses. PMID:6414547

Glazer, A N; Stryer, L

1983-01-01

167

Parametric instabilities during electron cyclotron heating of tandem mirrors  

NASA Technical Reports Server (NTRS)

Electron cyclotron resonance heating is one of the most commonly used methods of heating electrons in the plugs and in the thermal barriers of tandem mirrors. The intense coherent electromagnetic waves used for such heating are susceptible to parametric decay into other modes. Significant growth rates are found for the decay of either ordinary or extraordinary waves into two magnetized electron plasma waves. This and related effects may result in electron heating mechanisms rather different than those assumed in linear ray-tracing calculations. These results may help explain the unusual effects observed during heating of the Phaedrus tandem mirror device. In the general case, these instabilities may be strongly inhibited by density gradients.

Nicholson, D. R.

1984-01-01

168

MINIMARS: an attractive small tandem mirror fusion reactor  

SciTech Connect

Through the innovative design of a novel end plug scheme employing octopole MHD stabilization, we present the conceptual design of ''MIMIMARS'', 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 enables 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.

1985-11-13

169

Multilocus variable number tandem repeat analysis for Salmonella enterica subspecies  

Microsoft Academic Search

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,\\u000a and Newport). These allowed the selection of markers to develop the genotyping technique, multiple-locus VNTR analysis (MLVA).\\u000a These markers were used

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

2011-01-01

170

Tandem catalysis: a new approach to polypeptides and cyclic carbonates.  

PubMed

A new tandem catalytic system mediates very efficiently and selectively at room temperature two sequential reactions to produce relevant derivatives in one pot. Remarkably, this new concept of catalysis allows the facile synthesis of polypeptides and provides direct access to cyclic carbonates in high yields, through the incorporation of the carbon dioxide released from the initial step, thus achieving full-atom economy. PMID:25251079

Raman, Sumesh K; Brulé, Emilie; Tschan, Mathieu J-L; Thomas, Christophe M

2014-11-18

171

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

172

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

173

Azimuthal ambipolar potential variations and tandem mirror transport  

Microsoft Academic Search

Azimuthal ambipolar potential variations are induced by the magnetic drifts in a quadrupole tandem mirror. Consequently, radial E x B drifts occur and contribute along with the magnetic drifts to the total radial flux in a collisional plasma. This effect is studied self-consistently in the resonant-plateau regime assuming Maxwell-Boltzmann electrons along the field lines. A general form exhibiting the contribution

X. S. Lee; J. R. Myra; P. J. Catto

1983-01-01

174

Azimuthal ambipolar potential variations and tandem mirror transport  

Microsoft Academic Search

Azimuthal ambipolar potential variations are induced by the magnetic drifts in a quadrupole tandem mirror. Consequently, radial E x B drifts occur and contribute along with the magnetic drifts to the total radial flux in a collisional plasma. This effect is studied self-consistently in the resonant-plateau regime assuming Maxwell--Boltzmann electrons along the field lines. A general form exhibiting the contribution

X. S. Lee; J. R. Myra; P. J. Catto

1984-01-01

175

Azimuthal ambipolar potential variations and tandem mirror transport  

Microsoft Academic Search

Azimuthal ambipolar potential variations are induced by the magnetic drifts in a qlodrupole tandem mirror. Consequently, radial E×B drifts occur and contribute along with the magnetic drifts to the total radial flux in a collisional plasma. This effect is studied self-consistently in the resonant-plateau regime assuming Maxwell–Boltzmann electrons along the field lines. A general form exhibiting the contribution of the

X. S. Lee; J. R. Myra; P. J. Catto

1984-01-01

176

Tandem termination signal in plant mRNAs  

PubMed Central

It was proposed that if some mRNA characteristics resulted in a low efficiency of termination signal, an additional closely located stop codon (tandem stop codons) could be used to prevent the harmful readthrough. However, the role of tandem terminators in higher eukaryotes was not verified and remains hypothetical. In this work the sequence features of Arabidopsis thaliana and Oryza sativa mRNAs were analyzed. It was found that plant mRNAs with UGA terminator were characterized by a higher frequency of nonsense codons in the first triplet position of 3?-UTR that could result from a weak natural selection for “reserve” stop signal. Interestingly, the presence of tandem stop codons positively correlated with a specific amino acid composition in the C-terminal position of the encoded proteins. In particular, C-terminal glycine positively correlated with significantly higher frequencies of reserve terminators at the beginning positions of 3?-UTR in UGA-containing mRNAs. This finding coincides with some earlier observations concerning the role of glycine and its codons in inefficient termination of translation and recoding (e.g., 2A oligopeptide). PMID:21539902

Kochetov, Alex V.; Volkova, Oxana A.; Poliakov, Alexander; Dubchak, Inna; Rogozin, Igor B.

2011-01-01

177

Optimal design of high-efficiency tandem cells  

NASA Technical Reports Server (NTRS)

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 percent at one sun and over 30 percent 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. C.; Tsaur, B.-Y.; Palm, B. J.

1982-01-01

178

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

179

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

180

Dehydroxymethylepoxyquinomicin, a novel nuclear Factor-kappaB inhibitor, enhances antitumor activity of taxanes in anaplastic thyroid cancer cells.  

PubMed

Nuclear factor kappaB (NF-kappaB), as an antiapoptotic factor, crucially affects the outcomes of cancer treatments, being one of the major culprits of resistance to chemotherapy. In this study, we investigated whether dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-kappaB inhibitor, can enhance antitumor activities of taxanes in anaplastic thyroid cancer (ATC) cells. Taxanes induced NF-kappaB activation in ATC cells, which could compromise the therapeutic effect of the drugs. However, DHMEQ, by inhibiting the nuclear translocation of NF-kappaB, completely suppressed the DNA binding capacities of NF-kappaB and lowered the levels of nuclear NF-kappaB protein. Compared with single treatment (either taxane or DHMEQ), the combined treatment strongly potentiated apoptosis, confirmed by cell survival assay; Western blotting for poly (ADP-ribose) polymerase, caspase 3, X-linked inhibitor of apoptosis, and survivin; and flow cytometry for annexin V. Furthermore, we also demonstrate for the first time that the combined treatment showed significantly greater inhibitory effect on tumor growth in a nude mice xenograft model. These findings suggest that taxanes are able to induce NF-kappaB activation in ATC cells, which could attenuate antitumor activities of the drugs, but inhibition of NF-kappaB by DHMEQ creates a chemosensitive environment and greatly enhances apoptosis in taxanes-treated ATC cells in vitro and in vivo. Thus, DHMEQ may emerge as an attractive therapeutic strategy to enhance the response to taxanes in ATCs. PMID:18653704

Meng, Zhaowei; Mitsutake, Norisato; Nakashima, Masahiro; Starenki, Dmytro; Matsuse, Michiko; Takakura, Shu; Namba, Hiroyuki; Saenko, Vladimir; Umezawa, Kazuo; Ohtsuru, Akira; Yamashita, Shunichi

2008-11-01

181

Structural and biochemical characterizations of an intramolecular tandem coiled coil protein.  

PubMed

Coiled coil has served as an excellent model system for studying protein folding and developing protein-based biomaterials. Most designed coiled coils function as oligomers, namely intermolecular coiled coils. However, less is known about structural and biochemical behavior of intramolecular coiled coils where coiled coil domains are covalently linked in one polypeptide. Here we prepare a protein which harbors three coiled coil domains with two short linkers, termed intramolecular tandem coiled coil (ITCC) and characterize its structural and biochemical behavior in solution. ITCC consists of three coiled coil domains whose sequences are derived from Coil-Ser and its domain swapped dimer. Modifications include positioning E (Glu) residue at "e" and K (Lys) at "g" positions throughout heptad repeats to enhance ionic interaction among its constituent coiled coil domains. Molecular modeling of ITCC suggests a compact triple helical bundle structure with the second and the third coiled coil domains forming a canonical coiled coil. ITCC exists as a mixture of monomeric and dimeric species in solution. Small-angle X-ray scattering reveals ellipsoidal molecular envelopes for both dimeric and monomeric ITCC in solution. The theoretically modeled structures of ITCC dock well into the envelopes of both species. Higher ionic strength shifts the equilibrium into monomer with apparently more compact structure while secondary structure remains unchanged. Taken together, our results suggest that our designed ITCC is predominantly monomeric structure through the enhanced ionic interactions, and its conformation is affected by the concentration of ionic species in the buffer. PMID:25446089

Shin, Donghyuk; Kim, Gwanho; Kim, Gyuhee; Zheng, Xu; Kim, Yang-Gyun; Lee, Sangho

2014-12-12

182

TL tandem systems for the determination of effective energy in X radiation beams.  

PubMed

Tandem systems usually comprise two detectors with different radiation energy responses and are utilized to determine the effective energy of unknown radiation beams. The aim of this paper was to evaluate the influence of absorbed dose on tandem curves obtained for different TL materials. In the studied dose interval, the results demonstrate that there is no significant influence of dose on the tandem curves. Therefore, the reliability of these systems for the determination of radiation beam effective energy was confirmed. PMID:20097085

Oliveira, Mércia L; Maia, Ana F

2010-01-01

183

Monolithic, Ultra-Thin GaInP\\/GaAs\\/GaInAs Tandem Solar Cells  

Microsoft Academic Search

We present here a new approach to tandem cell design that offers near-optimum subcell bandgaps, as well as other special advantages related to cell fabrication, operation, and cost reduction. Monolithic, ultra-thin GaInP\\/GaAs\\/GaInAs triple-bandgap tandem solar cells use this new approach, which involves inverted epitaxial growth, handle mounting, and parent substrate removal. The optimal ~1-eV bottom subcell in the tandem affords

Mark Wanlass; Phil Ahrenkiel; David Albin; Jeff Carapella; Anna Duda; Keith Emery; Daniel Friedman; John Geisz; Kim Jones; Alan Kibbler; James Kiehl; Sarah Kurtz; William McMahon; Tom Moriarty; Jerry Olson; Aaron Ptak; Manuel Romero; Scott Ward

2006-01-01

184

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

185

Direct Assay of Enzymes in Heme Biosynthesis for the Detection of Porphyrias by Tandem Mass  

E-print Network

in hereditary coproporphyria (HCP), an autosomal dominant acute hepatic porphyria, which is characterized porphyria cutanea tarda and hereditary copro- porphyria, respectively. Electrospray ionization tandem mass

Gelb, Michael

186

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

187

Multistage Regulator Based on Tandem Promoters and CRISPR/Cas.  

PubMed

Accurately controlling expression of target genes between several designed levels is essential for low-noise gene network and dynamic range of gene expression. However, such manipulations have been hard to achieve due to technical limitations. Based on tandem promoters and CRISPR (clustered regularly interspaced short palindromic repeats)/Cas (CRISPR-associated) system, we constructed a multistage regulator that could stably regulate the expression of the reporter gene on three levels, with more than 2-fold difference between each of them. Our findings provide novel insights into constructing a more powerful gene regulation system. PMID:25524111

Jia, Hangxing; Liang, Tong; Wang, Zhaoning; He, Zhaoren; Liu, Yang; Yang, Lei; Zeng, Yan; Liu, Shaopeng; Tang, Linyi; Wang, Jianbo; Chen, Yu; Xie, Zhixiong

2014-12-19

188

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

189

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

190

Plasma performance study for the tandem mirror reactor  

SciTech Connect

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

Boghosian, B.M.

1980-01-01

191

Enantioselective tandem O-nitroso Aldol/Michael reaction.  

PubMed

This communication presents studies that illustrated nitroso Diels-Alder adduct has been obtained in uniformly high enantioselectivity via a tandem nitroso aldol/Michael reaction using an amine catalyst. The regiochemical outcome of this construction is documented to be the opposite to that of the normal nitroso aldol reaction, which has been determined by X-ray analysis. The reaction of the enone with silver-BINAP catalyst has also been investigated in conjunction with the control of regiochemistry in a stepwise process. PMID:15137750

Yamamoto, Yuhei; Momiyama, Norie; Yamamoto, Hisashi

2004-05-19

192

Tandem Measurements of Aerosol Properties—A Review of Mobility Techniques with Extensions  

Microsoft Academic Search

When multiple instruments are used in tandem it is possible to obtain more complete information on particle transport and physicochemical properties than can be obtained with a single instrument. This article discusses tandem measurements in which submicrometer particles classified according to electrical mobility are then characterized with one or more additional methods. Measurement combinations that are summarized here include mobility

D. Dutcher; M. Emery; J. Pagels; H. Sakurai; J. Scheckman; S. Qian; M. R. Stolzenburg; X. Wang; J. Yang; P. H. McMurry

2008-01-01

193

An unsupervised machine learning method for assessing quality of tandem mass spectra  

PubMed Central

Background In a single proteomic project, tandem mass spectrometers can produce hundreds of millions of tandem mass spectra. However, majority of tandem mass spectra are of poor quality, it wastes time to search them for peptides. Therefore, the quality assessment (before database search) is very useful in the pipeline of protein identification via tandem mass spectra, especially on the reduction of searching time and the decrease of false identifications. Most existing methods for quality assessment are supervised machine learning methods based on a number of features which describe the quality of tandem mass spectra. These methods need the training datasets with knowing the quality of all spectra, which are usually unavailable for the new datasets. Results This study proposes an unsupervised machine learning method for quality assessment of tandem mass spectra without any training dataset. This proposed method estimates the conditional probabilities of spectra being high quality from the quality assessments based on individual features. The probabilities are estimated through a constraint optimization problem. An efficient algorithm is developed to solve the constraint optimization problem and is proved to be convergent. Experimental results on two datasets illustrate that if we search only tandem spectra with the high quality determined by the proposed method, we can save about 56 % and 62% of database searching time while losing only a small amount of high-quality spectra. Conclusions Results indicate that the proposed method has a good performance for the quality assessment of tandem mass spectra and the way we estimate the conditional probabilities is effective. PMID:22759570

2012-01-01

194

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...

195

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

196

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

197

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.

198

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

Microsoft Academic Search

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

K. B. Lim; W. B. Tay

2010-01-01

199

Analyzing Proteomes and Protein Function Using Graphical Comparative Analysis of Tandem Mass Spectrometry Results  

Microsoft Academic Search

Although generating large amounts of proteomic data us- ing tandem mass spectrometry has become routine, there is currently no single set of comprehensive tools for the rigorous analysis of tandem mass spectrometry results given the large variety of possible experimental aims. Cur- rently available applications are typically designed for dis- playing proteins and posttranslational modifications from the point of view

K. Jill McAfee; Dexter T. Duncan; Michael Assink; Andrew J. Link

2006-01-01

200

Tandem 1;30 translocation: a new structural abnormality in the horse (Equus caballus)  

Microsoft Academic Search

A 1;30 tandem translocation was found in an 8-yr-old thoroughbred stallion referred because of reduced fertility. The diagnosis was confirmed by GTG and CBG staining. This is the first report of a tandem translocation in the horse.Copyright © 1996 S. Karger AG, Basel

S. E. Long

1996-01-01

201

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...

202

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

203

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

204

Negotiation of Meaning and Corrective Feedback in Japanese/English eTandem  

ERIC Educational Resources Information Center

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

Bower, Jack; Kawaguchi, Satomi

2011-01-01

205

In vitro enhancement effect of humic acid on the progression of lung cancer cells.  

PubMed

Humic acid, a group of polymer, resulting from the decomposition of organic matter has been implicated as a possible etiological factor for Black foot disease and cancer. However, the role of humic acid in carcinogenesis is not well clarified. In this study, we evaluated the enhancement effect of humic acid on the progression of A549 human lung cancer cells. Our findings showed that humic acid increased the migration, adhesion and invasion of A549 cells significantly after treatment at the concentration of 50 and 100 microg/ml for 24 and 48 h as compared with the untreated group. Results of zymography assay indicated that humic acid enhanced the activity of matrix metalloproteinase 9 (MMP-9). By western blotting analysis, humic acid increased the expression of phosphorylated focal adhesion kinase (FAK) and integrin alpha2 that may mediate cell motility and adhesion. Since the activation of signal pathways such as phosphoinositide 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinases (MAPKs) may play a role in the cell invasion, we detected the expression of phosphorylated Akt and phosphorylated MAPKs including extracellular signal-regulated kinase (ERK), Jun N-terminus kinase (JNK), and p38. The result indicated that all kinases stated above were activated by humic acid in A549 cells. However, by adding an inhibitor respectively in the invasion assay, only Akt, ERK, and JNK pathways were found to be involved in the enhancing the invasion of A549 cells by humic acid. In addition, results of electrophoretic mobility shift assay (EMSA) demonstrated that humic acid increased nuclear extract binding to the DNA probe of activator protein 1 (AP-1) and nuclear factor kappaB (NFkappaB) respectively, implying that humic acid enhanced the progression of A549 lung cancer cells through activating multiple signaling pathways including ERK, JNK, and PI3K/Akt and increasing the transcription activation of AP-1 and NFkappaB. PMID:19686714

Lee, Wei-Jiunn; Lu, Fung-Jou; Wang, Shan-Fu; Chen, Yun-Ru; Tseng, Tsui-Hwa

2009-10-30

206

Beyond junk-variable tandem repeats as facilitators of rapid evolution of regulatory and coding sequences.  

PubMed

Copy Number Variations (CNVs) and Single Nucleotide Polymorphisms (SNPs) have been the major focus of most large-scale comparative genomics studies to date. Here, we discuss a third, largely ignored, type of genetic variation, namely changes in tandem repeat number. Historically, tandem repeats have been designated as non functional "junk" DNA, mostly as a result of their highly unstable nature. With the exception of tandem repeats involved in human neurodegenerative diseases, repeat variation was often believed to be neutral with no phenotypic consequences. Recent studies, however, have shown that as many as 10% to 20% of coding and regulatory sequences in eukaryotes contain an unstable repeat tract. Contrary to initial suggestions, tandem repeat variation can have useful phenotypic consequences. Examples include rapid variation in microbial cell surface, tuning of internal molecular clocks in flies and the dynamic morphological plasticity in mammals. As such, tandem repeats can be useful functional elements that facilitate evolvability and rapid adaptation. PMID:24704980

Gemayel, Rita; Cho, Janice; Boeynaems, Steven; Verstrepen, Kevin J

2012-01-01

207

Beyond Junk-Variable Tandem Repeats as Facilitators of Rapid Evolution of Regulatory and Coding Sequences  

PubMed Central

Copy Number Variations (CNVs) and Single Nucleotide Polymorphisms (SNPs) have been the major focus of most large-scale comparative genomics studies to date. Here, we discuss a third, largely ignored, type of genetic variation, namely changes in tandem repeat number. Historically, tandem repeats have been designated as non functional “junk” DNA, mostly as a result of their highly unstable nature. With the exception of tandem repeats involved in human neurodegenerative diseases, repeat variation was often believed to be neutral with no phenotypic consequences. Recent studies, however, have shown that as many as 10% to 20% of coding and regulatory sequences in eukaryotes contain an unstable repeat tract. Contrary to initial suggestions, tandem repeat variation can have useful phenotypic consequences. Examples include rapid variation in microbial cell surface, tuning of internal molecular clocks in flies and the dynamic morphological plasticity in mammals. As such, tandem repeats can be useful functional elements that facilitate evolvability and rapid adaptation. PMID:24704980

Gemayel, Rita; Cho, Janice; Boeynaems, Steven; Verstrepen, Kevin J.

2012-01-01

208

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

209

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

210

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

211

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

212

Multipyrene Tandem Probes for Point Mutations Detection in DNA  

PubMed Central

Here we report design, synthesis and characterization of highly sensitive, specific and stable in biological systems fluorescent probes for point mutation detection in DNA. The tandems of 3?- and 5?-mono- and bis-pyrene conjugated oligo(2?-O-methylribonucleotides), protected by 3?-“inverted” thymidine, were constructed and their potential as new instruments for genetic diagnostics was studied. Novel probes have been shown to exhibit an ability to form stable duplexes with DNA target due to the stabilizing effect of multiple pyrene units at the junction. The relationship between fluorescent properties of developed probes, the number of pyrene residues at the tandem junction, and the location of point mutation has been studied. On the basis of the data obtained, we have chosen the probes possessing the highest fluorescence intensity along with the best mismatch discrimination and deletion and insertion detection ability. Application of developed probes for detection of polymorphism C677T in MTHFR gene has been demonstrated on model systems. PMID:24455205

Kholodar, Svetlana A.; Novopashina, Darya S.; Meschaninova, Mariya I.; Venyaminova, Alya G.

2013-01-01

213

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

214

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

215

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

216

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

217

Evaluating Tandem Language Learning by E-Mail: Report on a Bilateral Project. CLCS Occasional Paper No. 55.  

ERIC Educational Resources Information Center

The report details the Irish portion of an experiment in tandem language learning by electronic mail (e-mail). The partners were Trinity College, Dublin (Ireland) and Ruhr University, Bochum (Germany), funded by the European Union within the International E-Mail Tandem Network as part of a two-year project. Tandem language learning is a form of…

Little, David; Ushioda, Ema; Appel, Marie Christine; Moran, John; O'Rourke, Breffni; Schwienhorst, Klaus

218

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

219

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

220

The Tandem Repeats Enabling Reversible Switching between the Two Phases of ?-Lactamase Substrate Spectrum  

PubMed Central

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

Hwang, Junghyun; Kim, Karan; Nierman, William C.; Kim, Heenam Stanley

2014-01-01

221

GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects  

SciTech Connect

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

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

1995-01-01

222

De novo protein sequencing by combining top-down and bottom-up tandem mass spectra.  

PubMed

There are two approaches for de novo protein sequencing: Edman degradation and mass spectrometry (MS). Existing MS-based methods characterize a novel protein by assembling tandem mass spectra of overlapping peptides generated from multiple proteolytic digestions of the protein. Because each tandem mass spectrum covers only a short peptide of the target protein, the key to high coverage protein sequencing is to find spectral pairs from overlapping peptides in order to assemble tandem mass spectra to long ones. However, overlapping regions of peptides may be too short to be confidently identified. High-resolution mass spectrometers have become accessible to many laboratories. These mass spectrometers are capable of analyzing molecules of large mass values, boosting the development of top-down MS. Top-down tandem mass spectra cover whole proteins. However, top-down tandem mass spectra, even combined, rarely provide full ion fragmentation coverage of a protein. We propose an algorithm, TBNovo, for de novo protein sequencing by combining top-down and bottom-up MS. In TBNovo, a top-down tandem mass spectrum is utilized as a scaffold, and bottom-up tandem mass spectra are aligned to the scaffold to increase sequence coverage. Experiments on data sets of two proteins showed that TBNovo achieved high sequence coverage and high sequence accuracy. PMID:24874765

Liu, Xiaowen; Dekker, Lennard J M; Wu, Si; Vanduijn, Martijn M; Luider, Theo M; Toli?, Nikola; Kou, Qiang; Dvorkin, Mikhail; Alexandrova, Sonya; Vyatkina, Kira; Paša-Toli?, Ljiljana; Pevzner, Pavel A

2014-07-01

223

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

224

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

225

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

226

Long tandem arrays of complex repeat units in Chironomus telomeres.  

PubMed Central

A cloned 340-bp DNA fragment excised by EcoRI from the Chironomus pallividittatus genome has been localized to the telomeres by in situ hybridization as well as to connectives between telomeres. No hybridization was observed in other regions of the chromosomes. Another cloned EcoRI fragment, 525 bp long has also been studied. This represents a partial duplication of the 340-bp sequence. Genomic blot hybridization experiments show that the 340-bp sequence is a representative monomeric unit of tandemly repeated arrays which account for 1.2% of the Chironomus genome, on average 300 kb per telomere. The repeat unit contains two types of subrepeats each present twice per repeat unit. Northern blot hybridization experiments show that the telomere-associated sequences are transcribed into a discrete RNA species approximately 20 kb in size. The evolution of this telomere-associated DNA is discussed. Images Fig. 1. Fig. 3. Fig. 4. Fig. 5. Fig. 6. PMID:4006906

Saiga, H; Edström, J E

1985-01-01

227

Tandem synthesis of alternating polyesters from renewable resources  

PubMed Central

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

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

2011-01-01

228

An RF heated tandem mirror plasma propulsion study  

NASA Technical Reports Server (NTRS)

Experimental results on a tandem mirror hybrid plume rocket involving a three-stage system of plasma injection, heating, and subsequent injection through a magnetic nozzle are presented. In the experiments, a plasma is created by breaking down the gas with electron cyclotron resonance heating at 2 kW in the central cell, and the ion species is then heated to high temperatures with ion cyclotron resonance heating at 10 kW in the end cell. A Langmuir probe measured an electron density of 2.5 x 10 to the 16th/cu m and a temperature of 100 eV in the central cell and an ion density of 1.25 x 10 to the 17th/cu m and a temperature of 500 eV in the end cell.

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

1989-01-01

229

Phase lag between vortex shedding from two tandem bluff bodies  

NASA Astrophysics Data System (ADS)

This paper presents a work on the phase lag (?) between vortex sheddings from two tandem cylinders of various shapes and its influence on fluctuating lift on the upstream cylinder. A differential equation of ?, d?=[4?fs/(2Vc-dVc)] dx, is derived, where fs is the vortex shedding frequency, Vc is the convective velocity of vortices, and x is the downstream distance from the upstream cylinder. Applying the condition ?=2? at L=Lc*, as obtained from experimental data, the equation yields ?=2.44? St(L-Lc*)+2?, where St is the Strouhal number, L is the normalized cylinder center-to-center spacing and Lc* is the critical spacing defined as the minimum L at which the upstream cylinder could shed vortices in the gap between the cylinders. This relationship agrees well with experimental data previously reported as well as presently measured.

Mahbub Alam, Md.; Zhou, Y.

2007-02-01

230

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

231

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

232

Physics issues in mirror and tandem mirror systems  

SciTech Connect

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

Post, R.F.

1984-06-15

233

Features-Based Deisotoping Method for Tandem Mass Spectra  

PubMed Central

For high-resolution tandem mass spectra, the determination of monoisotopic masses of fragment ions plays a key role in the subsequent peptide and protein identification. In this paper, we present a new algorithm for deisotoping the bottom-up spectra. Isotopic-cluster graphs are constructed to describe the relationship between all possible isotopic clusters. Based on the relationship in isotopic-cluster graphs, each possible isotopic cluster is assessed with a score function, which is built by combining nonintensity and intensity features of fragment ions. The non-intensity features are used to prevent fragment ions with low intensity from being removed. Dynamic programming is adopted to find the highest score path with the most reliable isotopic clusters. The experimental results have shown that the average Mascot scores and F-scores of identified peptides from spectra processed by our deisotoping method are greater than those by YADA and MS-Deconv software. PMID:22262971

Yuan, Zheng; Shi, Jinhong; Lin, Wenjun; Chen, Bolin; Wu, Fang-Xiang

2011-01-01

234

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

235

Internal solitary wave propagation observed by tandem satellites  

NASA Astrophysics Data System (ADS)

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

236

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

237

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

238

Intermediate layers for tandem structure of bulk heterojunction photovoltaic cells  

NASA Astrophysics Data System (ADS)

For advanced organic thin film photovoltaic cell, stacked structure of single cells, tandem structure, would be a key issue. Many kinds of tandem structure have been already reported. When an appropriate intermediate layer was inserted between the single cells, open circuit voltage (Voc) can be doubled compared with the single cell. For small molecules, vacuum evaporation can be applicable for fabrication. Systematic investigations have been made to reveal the requirement for the intermediate materials. Quite thin, a few nm thick, metal layer can act as intermediate layer[1]. The metal cannot form continuous layer but island lake structure in such small amount. On the other hand, the combination of the metal oxide (such as ZnO, TiO2 and ITO) and PEDOT:PSS are used for the intermediate layer. We need to reveal minimum requirement for the intermediate materials for polymer based bulkhererojunction cells for low-cost high performance organic photovoltaic cells. We have developed a polymer thin film preparation technique, Evaporative Spray Deposition using Ultradilute Solution (ESDUS)[2]. This method has enabled fabricating organic thin films applicable to polymer light-emitting diodes, organic photovoltaics and organic field-effect transistors13 from highly diluted solutions of 1-10 ppm. Moreover, it has been exhibited that a successive polymer layer can be deposited without damaging the preceding polymer layer by use of a same solvent for each layer deposition. We conduct the systematic investigation of the intermediate materials. Onto the bottom cell/intermediate layer, top cell can be deposited by use of ESDUS.

Kawanami, Akito; Fujita, Katsuhiko

2012-09-01

239

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

240

SVM-RFE based feature selection for tandem mass spectrum quality assessment.  

PubMed

In literature, hundreds of features have been proposed to assess the quality of tandem mass spectra. However, many of these features are irrelevant in describing the spectrum quality and they can degenerate the spectrum quality assessment performance. We propose a two-stage Recursive Feature Elimination based on Support Vector Machine (SVM-RFE) method to select the highly relevant features from those collected in literature. Classifiers are trained to verify the relevance of selected features. The results demonstrate that these selected features can better describe the quality of tandem mass spectra and hence improve the performance of tandem mass spectrum quality assessment. PMID:21491845

Ding, Jiarui; Shi, Jinhong; Wu, Fang-Xiang

2011-01-01

241

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

242

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

243

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

244

Supporting Information Tandem Catalytic Conversion of Glucose to 5-Hydroxymethylfurfural with  

E-print Network

1 Supporting Information Tandem Catalytic Conversion of Glucose to 5-Hydroxymethylfurfural/buffer were performed in pressure-relief reaction vials from Chemglass (Vineland, NJ). One-pot reactions were

Zhao, Huimin

245

Sequence-specific DNA alkylation by tandem Py-Im polyamide conjugates.  

PubMed

Tandem N-methylpyrrole-N-methylimidazole (Py-Im) polyamides with good sequence-specific DNA-alkylating activities have been designed and synthesized. Three alkylating tandem Py-Im polyamides with different linkers, which each contained the same moiety for the recognition of a 10?bp DNA sequence, were evaluated for their reactivity and selectivity by DNA alkylation, using high-resolution denaturing gel electrophoresis. All three conjugates displayed high reactivities for the target sequence. In particular, polyamide 1, which contained a ?-alanine linker, displayed the most-selective sequence-specific alkylation towards the target 10?bp DNA sequence. The tandem Py-Im polyamide conjugates displayed greater sequence-specific DNA alkylation than conventional hairpin Py-Im polyamide conjugates (4 and 5). For further research, the design of tandem Py-Im polyamide conjugates could play an important role in targeting specific gene sequences. PMID:24942204

Taylor, Rhys Dylan; Kawamoto, Yusuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

2014-09-01

246

Supplemental Material for DNA Fingerprint Analysis of Three Short Tandem Repeat  

E-print Network

1 Supplemental Material for ­ DNA Fingerprint Analysis of Three Short Tandem Repeat STR Loci genetics and its significance in DNA fingerprint analysis (plus an example calculation of allelic frequency

Love, John J.

247

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

248

Low driving voltage simplified tandem organic light-emitting devices by using exciplex-forming hosts  

NASA Astrophysics Data System (ADS)

Tandem organic light-emitting devices (OLEDs), i.e., OLEDs containing multiple electroluminescence (EL) units that are vertically stacked, are attracting significant interest because of their ability to realize high current efficiency and long operational lifetime. However, stacking multiple EL units in tandem OLEDs increases driving voltage and complicates fabrication process relative to their standard single unit counterparts. In this paper, we demonstrate low driving voltage tandem OLEDs via utilizing exciplex-forming hosts in the EL units instead of conventional host materials. The use of exciplex-forming hosts reduces the charge injection barriers and the trapping of charges on guest molecules, resulting in the lower driving voltage. The use of exciplex-forming hosts also allows using fewer layers, hence simpler EL configuration which is beneficial for reducing the fabrication complexity of tandem OLEDs.

Zhou, Dong-Ying; Cui, Lin-Song; Zhang, Ying-Jie; Liao, Liang-Sheng; Aziz, Hany

2014-10-01

249

Optimal Audio Transmission over Wireless Tandem Channels Ala' Khalifeh Homayoun Yousefi'zadeh  

E-print Network

1 Optimal Audio Transmission over Wireless Tandem Channels Ala' Khalifeh Homayoun Yousefi propose a statistical optimization framework for transmitting audio sequences over wireless links. Our proposed framework protects audio frames against both temporally cor- related random bit errors introduced

Yousefi'zadeh, Homayoun

250

Aerodynamic characteristics of two-dimensional sharp-edged objects in tandem arrangement?)  

Microsoft Academic Search

The present analysis addresses the problem of the aerodynamic loads of two pris- matic bodies in tandem arrangement. Two identical square cross-section prismatic bodies arranged in tandem are considered and represent a two-dimensional config- uration. The program of the study consists of parallel wind-tunnel experiments and numerical simulation performed with the use of a phase-averaged form of k ? ?

R. GNATOWSKA

251

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

252

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

Microsoft Academic Search

The objective of this project is to improve the performance of the efficiency, thrust and lift of flapping wings in tandem\\u000a arrangement. This research investigates the effect of the arrangement of the airfoils in tandem on the performance of the\\u000a airfoils by varying the phase difference and distance between the airfoils. Three flapping configurations from an earlier\\u000a phase of a

K. B. Lim; W. B. Tay

2010-01-01

253

Integrated tandem traveling-wave electroabsorption modulators for >100 Gbit\\/s OTDM applications  

Microsoft Academic Search

Integrated tandem traveling-wave electroabsorption modulators are demonstrated as high-speed optical short pulse generators and demultiplexers for >100 Gbit\\/s optical time-division-multiplexed systems. The tandem significantly increases the extinction ratio and further compresses the optical pulses in comparison to a single modulator. An extinction ratio of ?50 dB is achieved while optical pulses of 4-6 ps width at 30-40 GHz are generated.

Volkan Kaman; Yi-Jen Chiu; Thomas Liljeberg; Sheng Z. Zhang; John E. Bowers

2000-01-01

254

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

PubMed

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

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

2015-01-01

255

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

PubMed

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

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

2014-09-01

256

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

257

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

258

Quantitative analysis of acetaminophen and its primary metabolites in small plasma volumes by liquid chromatography-tandem mass spectrometry.  

PubMed

A fast and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the simultaneous determination of acetaminophen (APAP) and its glucuronide and sulfate metabolites (APAP-GLU and APAP-SUL) in small plasma volumes. This method included a simple step of sample preparation and a chromatographic separation on an LC-MS-MS system equipped with an electrospray ionization source and a tandem triple quadrupole mass spectrometer in multiple reaction monitoring mode. The analytes and internal standard, APAP deuterated analog, were separated on a C18 column (3.0 µm, 2.1 × 100 mm), using aqueous 1% formic acid and methanol (80:20, v/v) as the mobile phase. The LC-MS-MS method was validated for accuracy, precision, linearity, extraction efficiency, process efficiency and matrix effect. Calibration curves were obtained by fortifying drug-free plasma and ranges of linearity were set between 0.25-20 mg/L. The mean correlation coefficients, r², were >0.99 for APAP and its metabolites. The inter-day and intra-day precision values were less than 11.75 and 13.03%, respectively, at the lower limit of quantification concentration. The usability of the method was demonstrated by studying APAP metabolism in C57BL/6J wild-type and obese ob/ob female mice, in which only small plasma volumes were available. The results showed that APAP glucuronidation was enhanced in obese mice, suggesting that changes in APAP metabolism could modify its toxicity in obesity and related fatty liver disease. PMID:23316031

Gicquel, Thomas; Aubert, Jacinthe; Lepage, Sylvie; Fromenty, Bernard; Morel, Isabelle

2013-03-01

259

Sex-Linked Pheromone Receptor Genes of the European Corn Borer, Ostrinia nubilalis, Are in Tandem Arrays  

PubMed Central

Background Tuning of the olfactory system of male moths to conspecific female sex pheromones is crucial for correct species recognition; however, little is known about the genetic changes that drive speciation in this system. Moths of the genus Ostrinia are good models to elucidate this question, since significant differences in pheromone blends are observed within and among species. Odorant receptors (ORs) play a critical role in recognition of female sex pheromones; eight types of OR genes expressed in male antennae were previously reported in Ostrinia moths. Methodology/Principal Findings We screened an O. nubilalis bacterial artificial chromosome (BAC) library by PCR, and constructed three contigs from isolated clones containing the reported OR genes. Fluorescence in situ hybridization (FISH) analysis using these clones as probes demonstrated that the largest contig, which contained eight OR genes, was located on the Z chromosome; two others harboring two and one OR genes were found on two autosomes. Sequence determination of BAC clones revealed the Z-linked OR genes were closely related and tandemly arrayed; moreover, four of them shared 181-bp direct repeats spanning exon 7 and intron 7. Conclusions/Significance This is the first report of tandemly arrayed sex pheromone receptor genes in Lepidoptera. The localization of an OR gene cluster on the Z chromosome agrees with previous findings for a Z-linked locus responsible for O. nubilalis male behavioral response to sex pheromone. The 181-bp direct repeats might enhance gene duplications by unequal crossovers. An autosomal locus responsible for male response to sex pheromone in Heliothis virescens and H. subflexa was recently reported to contain at least four OR genes. Taken together, these findings support the hypothesis that generation of additional copies of OR genes can increase the potential for male moths to acquire altered specificity for pheromone components, and accordingly, facilitate differentiation of sex pheromones. PMID:21526121

Yasukochi, Yuji; Miura, Nami; Nakano, Ryo; Sahara, Ken; Ishikawa, Yukio

2011-01-01

260

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

261

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

262

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

263

Photosensitized oxidation of phosphatidylethanolamines monitored by electrospray tandem mass spectrometry.  

PubMed

Photodynamic therapy combines visible light and a photosensitizer (PS) in the presence of molecular oxygen to generate reactive oxygen species able to modify biological structures such as phospholipids. Phosphatidylethanolamines (PEs), being major phospholipid constituents of mammalian cells and membranes of Gram-negative bacteria, are potential targets of photosensitization. In this work, the oxidative modifications induced by white light in combination with cationic porphyrins (Tri-Py(+)-Me-PF and Tetra-Py(+)-Me) were evaluated on PE standards. Electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS) were used to identify and characterize the oxidative modifications induced in PEs (POPE: PE 16:0/18:1, PLPE: PE 16:0/18:2, PAPE: PE 16:0/20:4). Photo-oxidation products of POPE, PLPE and PAPE as hydroxy, hydroperoxy and keteno derivatives and products due to oxidation in ethanolamine polar head were identified. Hydroperoxy-PEs were found to be the major photo-oxidation products. Quantification of hydroperoxides (PE-OOH) allowed differentiating the potential effect in photodamage of the two porphyrins. The highest amounts of PE-OOH were notorious in the presence of Tri-Py(+)-Me-PF, a highly efficient PS against bacteria. The identification of these modifications in PEs is an important key point in the understanding cell damage processes underlying photodynamic therapy approaches. PMID:24338891

Melo, Tânia; Santos, Nuno; Lopes, Diana; Alves, Eliana; Maciel, Elisabete; Faustino, Maria A F; Tomé, João P C; Neves, Maria G P M S; Almeida, Adelaide; Domingues, Pedro; Segundo, Marcela A; Domingues, M Rosário M

2013-12-01

264

Trienamines in asymmetric organocatalysis: Diels-Alder and tandem reactions.  

PubMed

The discovery of a novel activation mode provided by organocatalysis is presented. It is demonstrated that the merger of optically active secondary amines and polyenals generates reactive trienamine intermediates, which readily participate in Diels-Alder reactions with different classes of dienophiles, hence, providing a facile entry to highly complex molecular frameworks with excellent stereocontrol. For the Diels-Alder reactions with 3-olefinic oxindoles, spirocyclic oxidoles are formed in high yields, and with enantioselectivities in the range of 94-98% ee. It is demonstrated, that some of these products can be transformed into the hexahydrofuro[2,3-b]indole fragment. The organocatalytic trienamine concept has been extended to also include Diels-Alder reactions of olefins substituted with cyanoacetates providing multifunctional cyclohexenes with three contiguous stereocenters in high yield and good stereocontrol. The novelty of this activation strategy lies within the perfect chirality relay over a distance of up to eight bonds. Moreover, we also present the first trienamine tandem reaction by combining trienamine catalysis with enamine activation. In addition to the experimental results, a detailed mechanistic survey is also provided including NMR spectroscopic studies and calculations of the reactive trienamine intermediates, rationalizing the origin of stereochemistry. PMID:21405125

Jia, Zhi-Jun; Jiang, Hao; Li, Jun-Long; Gschwend, Björn; Li, Qing-Zhu; Yin, Xiang; Grouleff, Julie; Chen, Ying-Chun; Jørgensen, Karl Anker

2011-04-01

265

Learning Peptide-Spectrum Alignment Models for Tandem Mass Spectrometry  

PubMed Central

We present a peptide-spectrum alignment strategy that employs a dynamic Bayesian network (DBN) for the identification of spectra produced by tandem mass spectrometry (MS/MS). Our method is fundamentally generative in that it models peptide fragmentation in MS/MS as a physical process. The model traverses an observed MS/MS spectrum and a peptide-based theoretical spectrum to calculate the best alignment between the two spectra. Unlike all existing state-of-the-art methods for spectrum identification that we are aware of, our method can learn alignment probabilities given a dataset of high-quality peptide-spectrum pairs. The method, moreover, accounts for noise peaks and absent theoretical peaks in the observed spectrum. We demonstrate that our method outperforms, on a majority of datasets, several widely used, state-of-the-art database search tools for spectrum identification. Furthermore, the proposed approach provides an extensible framework for MS/MS analysis and provides useful information that is not produced by other methods, thanks to its generative structure. PMID:25298752

Halloran, John T.; Bilmes, Jeff A.; Noble, William S.

2014-01-01

266

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

267

Vacuum vessel for the tandem Mirror Fusion Test Facility  

SciTech Connect

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

Gerich, J.W.

1986-03-10

268

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

269

Tandem "click" reactions at acetylene-terminated Si(100) monolayers.  

PubMed

We demonstrate a simple method for coupling alkynes to alkynes. The method involves tandem azide-alkyne cycloaddition reactions ("click" chemistry) for the immobilization of 1-alkyne species onto an alkyne modified surface in a one-pot procedure. In the case presented, these reactions take place on a nonoxidized Si(100) surface although the approach is general for linking alkynes to alkynes. The applicability of the method in the preparation of electrically well-behaved functionalized surfaces is demonstrated by coupling an alkyne-tagged ferrocene species onto alkyne-terminated Si(100) surfaces. The utility of the approach in biotechnology is shown by constructing a DNA sensing interface by derivatization of the acetylenyl surface with commercially available alkyne-tagged oligonucleotides. Cyclic voltametry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and X-ray reflectometry are used to characterize the coupling reactions and performance of the final modified surfaces. These data show that this synthetic protocol gives chemically well-defined, electronically well-behaved, and robust (bio)functionalized monolayers on silicon semiconducting surfaces. PMID:21557551

Ciampi, Simone; James, Michael; Michaels, Pauline; Gooding, J Justin

2011-06-01

270

Probabilistic consensus scoring improves tandem mass spectrometry peptide identification.  

PubMed

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

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

2011-08-01

271

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

272

The Tandem-RFQ Linac Booster at Sandia National Laboratories  

NASA Astrophysics Data System (ADS)

A booster linac based on the Radio Frequency Quadrupole (RFQ linac) has been put into routine operation on the 6.5 MV EN tandem accelerator at the Sandia National Laboratories (SNL) Ion Beam Materials Research Lab (IBMRL) for Radiation Effects Microscopy (REM) experiments with high energy, heavy ion beams. The booster linac consists of two RFQ stages that accelerate heavy ions with m/q < 8 from 0.25 MeV/amu up to 1.22 MeV/amu in the first stage and to 1.90 MeV/amu in the second stage to produce high Linear Energy Transfer (LET) ions for REM. This RFQ linac has a total length of 6.0 meters and is installed on a new experimental beam line at the SNL IBMRL to measure single-event upset (SEU) cross-sections of integrated circuits (ICs) and to perform radiation hardness research using REM with the associated Ion Electron Emission Microscope (IEEM). This paper presents the recent beam measurement results from operation of the RFQ linac with beams from silicon to gold and compares these results with theoretical beam dynamics calculations. It also describes the details of the experiments to measure SEU cross-sections and IEEM.

McDaniel, F. D.; Doyle, B. L.; Rossi, P.; Buller, D. L.; Hamm, R. W.; Schone, H.

2003-08-01

273

Tandem mass spectrometry of multiply charged peptides and proteins  

SciTech Connect

In the past two years electrospray ionization (ESI), originally described by Dole and coworkers and reinvigorated by Fenn and coworkers, has received considerable attention as a soft ionization source for mass spectrometry. The ESI method produces intact, multiply charged, gas phase molecular ions of peptides and proteins from aqueous solution with mass to charge ratios (m/a) that are easily within the range of quadrupole mass spectrometers. Because of the possible additional structural information from collisionally induced dissociation (CID)/tandem mass spectrometry, multiply charged ions are likely candidates for examination by this technique, possibly producing all or significant portions of the amino acid sequence. Although the multiply charged ions give abundant fragmentation, it is still a question whether meaningful fragmentation can be efficiently produced by CID. It would also be anticipated that the charge state of the parent ion might significantly affect the daughter ion spectra both in ions observed and their intensities. Three peptides, mellitin, glucagon, and the synthetic T/sub 1/ trypstic fragment of glucagon, and the protein cytochrome-c, have been investigated to examine these issues. 5 refs., 1 fig.

Barinaga, C.J.; Udseth, H.R.; Smith, R.D.

1989-05-01

274

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

PubMed Central

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

2014-01-01

275

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

276

Novel Tandem Biotransformation Process for the Biosynthesis of a Novel Compound, 4-(2,3,5,6-Tetramethylpyrazine-1)-4?-Demethylepipodophyllotoxin?  

PubMed Central

According to the structure of podophyllotoxin and its structure-function relationship, a novel tandem biotransformation process was developed for the directional modification of the podophyllotoxin structure to directionally synthesize a novel compound, 4-(2,3,5,6-tetramethylpyrazine-1)-4?-demethylepipodophyllotoxin (4-TMP-DMEP). In this novel tandem biotransformation process, the starting substrate of podophyllotoxin was biotransformed into 4?-demethylepipodophyllotoxin (product 1) with the demethylation of the methoxyl group at the 4? position by Gibberella fujikuroi SH-f13, which was screened out from Shennongjia prime forest humus soil (Hubei, China). 4?-Demethylepipodophyllotoxin (product 1) was then biotransformed into 4?-demethylpodophyllotoxone (product 2) with the oxidation of the hydroxyl group at the 4 position by Alternaria alternata S-f6, which was screened out from the gathered Dysosma versipellis plants in the Wuhan Botanical Garden, Chinese Academy of Sciences. Finally, 4?-demethylpodophyllotoxone (product 2) and ligustrazine were linked with a transamination reaction to synthesize the target product 4-TMP-DMEP (product 3) by Alternaria alternata S-f6. Compared with podophyllotoxin (i.e., a 50% effective concentration [EC50] of 529 ?M), the EC50 of 4-TMP-DMEP against the tumor cell line BGC-823 (i.e., 0.11 ?M) was significantly reduced by 5,199 times. Simultaneously, the EC50 of 4-TMP-DMEP against the normal human proximal tubular epithelial cell line HK-2 (i.e., 0.40 ?M) was 66 times higher than that of podophyllotoxin (i.e., 0.006 ?M). Furthermore, compared with podophyllotoxin (i.e., log P = 0.34), the water solubility of 4-TMP-DMEP (i.e., log P = 0.66) was significantly enhanced by 94%. For the first time, the novel compound 4-TMP-DMEP with superior antitumor activity was directionally synthesized from podophyllotoxin by the novel tandem biotransformation process developed in this work. PMID:21398491

Tang, Ya-Jie; Zhao, Wei; Li, Hong-Mei

2011-01-01

277

Penetration enhancers  

Microsoft Academic Search

One long-standing approach for improving transdermal drug delivery uses penetration enhancers (also called sorption promoters or accelerants) which penetrate into skin to reversibly decrease the barrier resistance. Numerous compounds have been evaluated for penetration enhancing activity, including sulphoxides (such as dimethylsulphoxide, DMSO), Azones (e.g. laurocapram), pyrrolidones (for example 2-pyrrolidone, 2P), alcohols and alkanols (ethanol, or decanol), glycols (for example propylene

Adrian C Williams; Brian W Barry

2004-01-01

278

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

279

Deep Conservation of Human Protein Tandem Repeats within the Eukaryotes  

PubMed Central

Tandem repeats (TRs) are a major element of protein sequences in all domains of life. They are particularly abundant in mammals, where by conservative estimates one in three proteins contain a TR. High generation-scale duplication and deletion rates were reported for nucleic TR units. However, it is not known whether protein TR units can also be frequently lost or gained providing a source of variation for rapid adaptation of protein function, or alternatively, tend to have conserved TR unit configurations over long evolutionary times. To obtain a systematic picture, we performed a proteome-wide analysis of the mode of evolution for human protein TRs. For this purpose, we propose a novel method for the detection of orthologous TRs based on circular profile hidden Markov models. For all detected TRs, we reconstructed bispecies TR unit phylogenies across 61 eukaryotes ranging from human to yeast. Moreover, we performed additional analyses to correlate functional and structural annotations of human TRs with their mode of evolution. Surprisingly, we find that the vast majority of human TRs are ancient, with TR unit number and order preserved intact since distant speciation events. For example, ?61% of all human TRs have been strongly conserved at least since the root of all mammals, approximately 300 Ma. Further, we find no human protein TR that shows evidence for strong recent duplications and deletions. The results are in contrast to the high generation-scale mutability of nucleic TRs. Presumably, most protein TRs fold into stable and conserved structures that are indispensable for the function of the TR-containing protein. All of our data and results are available for download from http://www.atgc-montpellier.fr/TRE. PMID:24497029

Schaper, Elke; Gascuel, Olivier; Anisimova, Maria

2014-01-01

280

Tandem Fourier transform mass spectrometry of large molecules  

SciTech Connect

Fourier-transform mass spectrometry has a number of key advantages, including simultaneous ion detection over a wide mass range, ultra-high resolution, and extensive capabilities for tandem mass spectrometry (MS/MS, even MS{sup n}). Here, new methods for soft ionization including {sup 252}Cf plasma desorption, 193 nm laser desorption, multiphoton ionization, and electrospray ionization (ESI) are demonstrated to produce abundant molecular ion species from a variety of compounds; ESI spectra of peptides as large as carbonic anhydrase (29,000 Da) with as many as 33+ charges are shown. Sensitivity can be improved up to 100x by remeasuring high mass ions multiple times; after excitation to a larger orbit for detection, energy lost through collisions with background neutrals returns these ions to the center of the cell where they are available for detection or dissociation in subsequent measurements. Photodissociation with 193 nm deposits 6.4 eV per photon absorbed, and produces spectra with extensive sequence information for a variety of peptides with dissociation efficiencies approaching 100%. Surface induced dissociation is demonstrated to produce structurally-useful fragmentation for peptides up to m/z 3100, a mass range where collisionally activated dissociation provides little information. Sensitivity for MS/MS and MS{sup n} measurements is substantially improved by simultaneously recording MS-II spectra of scores of precursors using the Hadamard deconvolution approach. Results with an eleven component mixture demonstrate a signal-to-noise (S/N) gain of 1.8x, as predicted by theory. A Hadamard of differences method is proposed in which all precursors are simultaneously dissociated such that posed in which all precursors are simultaneously dissociated such that MS{sup n} spectra of each of these could be obtained without additional time or sample over measuring just one (with the same S/N) individually.

Williams, E.R.

1990-01-01

281

Flow around two tandem square cylinders near a plane wall  

NASA Astrophysics Data System (ADS)

An experimental study has been conducted to investigate the flow around two identical square cylinders in tandem arrangement and placed near a plane wall at a Reynolds number of 6,300. The inter-cylinder spacing ratio was varied from S * = 0.5 to 6, and the cylinder-to-wall gap ratio from G * = 0.25 to 2. Totally, 42 cases were considered to systematically examine the effects of wall proximity and the mutual interference between the two cylinders in the normalized gap-spacing ( G *- S *) plane. The flow fields were captured using digital particle image velocimetry, in conjunction with measurements of the fluid forces (drag and lift) acting on the downstream cylinder using a piezoelectric load cell. The results show that the flow is highly dependent on the combined values of G * and S *. Categories relating to G * could be broadly classified as small-gap regime ( G * < 0.5) at which periodic vortex shedding from the cylinders is suppressed, intermediate-gap regime (0.5 < G * < 1) where vortex shedding occurs but is under the influence of the wall proximity, and large-gap regime ( G * > 1) where the wall effects become negligible. Similarly, the flow interference between the two cylinders can be divided into three basic categories as a function of S *, namely, shielding regime at S * < 1, reattachment regime at 1 < S * < 3, and impinging regime at S * > 3. Variations of force coefficients, amplitude spectra, Strouhal numbers, and Reynolds shear stress with G * and S * are presented to characterize the different flow regimes.

Wang, X. K.; Hao, Z.; Zhang, J.-X.; Tan, S. K.

2014-10-01

282

Early synthetic dyes--a challenge for tandem mass spectrometry.  

PubMed

The present study concerns identification of early yellow synthetic dyes from silk fibers taken from the 1930 spring color palette of the Lyon Dyers' Guild (La Chambre Syndicale des Teinturiers). The identification was based mainly on the electrospray ionization tandem mass spectrometry spectra obtained in the positive and negative ion modes. This technique was combined with high-performance liquid chromatography, which enabled separation of the analyzed compounds. Spectra registered for each of the examined synthetic dye allowed identification of their lost fragments. Moreover, isotopic profiles and exact measurements of m/z by using time of flight analyzer made possible to evaluate their elemental composition. In consequence, all obtained data, including UV-vis spectra, allowed to reconstruct molecular structures of examined colorants. Due to the lack of standards, the identification of the dyes was based only on the registration of fragment and quasi-molecular ions, what is rather uncommon in such analysis and means groping for the correct structure rather than proving signal identity by comparison with standards. Depending on substituents present in dye molecules, the lost fragments of the examined compounds involved SO(2), NO(•), NO(2)(•), CH(4), C(2)H(4), C(2)H(5)(•), C(2)H(6), CH(2)=N-CH(3), (CH(3))(2)NH, CH(2)=?NH, CH(3)-NH(2), as well as CO and CO(2). The performed study led to identification of various colorants: rhodamine 6?G, rhodamine B, malachite green, quinoline yellow, picric acid and acetoquinone yellow 5JZ. PMID:23378085

Lech, Katarzyna; Wilicka, Ewa; Witowska-Jarosz, Janina; Jarosz, Maciej

2013-02-01

283

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

284

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

285

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

286

Tandem solar cells deposited using hot-wire chemical vapor deposition  

NASA Astrophysics Data System (ADS)

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

van Veen, M. K.

2003-05-01

287

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

288

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

2015-01-21

289

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

290

Tandem organic light-emitting diode with a molybdenum tri-oxide thin film interconnector layer  

NASA Astrophysics Data System (ADS)

A 10-nm-thick molybdenum tri-oxide (MoO3) thin film was used as the interconnector layer in tandem organic light-emitting devices (OLEDs). The tandem OLEDs with two identical emissive units consisting of N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB)/tris(8-hydroxyquinoline) aluminum (Alq3) exhibited current efficiency-current density characteristics superior to the conventional single-unit devices. At 20 mA/cm2, the current efficiency of the tandem OLEDs using the interconnector layers of MoO3 thin film was about 4.0 cd/A, which is about twice that of the corresponding conventional single-unit device (1.8 cd/A). The tandem OLED showed a higher power efficiency than the conventional single-unit device for luminance over 1200 cd/m2. The experimental results demonstrated that a MoO3 thin film with a proper thickness can be used as an effective interconnector layer in tandem OLEDs. Such an interconnector layer can be easily fabricated by simple thermal evaporation, greatly simplifying the device processing and fabrication processes required by previously reported interconnector layers. A possible explanation was proposed for the carrier generation of the MoO3 interconnector layer.

Lu, Fei-Ping; Wang, Qian; Zhou, Xiang

2013-03-01

291

Evidence showing duplication and recombination of cel genes in tandem from hyperthermophilic Thermotoga sp.  

PubMed

This study was conducted to assess the gene duplication and diversification of tandem cellulase genes in thermophilic bacteria. The tandem cellulase genes cel5C and cel5D were cloned from Thermotoga maritima MSB8, and a survey of the thermophilic bacterial genome for tandem cel genes from the databases was carried out. A clone having 2.3 kb fragment from T. maritima MSB8 showed cellulase activity, which had two open reading frames in tandem (cel5C and cel5D). The cel5C gene has 954 bp, which encodes a protein of 317 amino acid residues with a signal peptide of 23 amino acids, and the other gene cel5D consisting of 990 bp encoding a protein of 329 amino acid residues. These two proteins have similarity with the enzymes of glycosyl hydrolase family 5. From the enzyme assay, it was observed that Cel5C was extracellular and Cel5D was intracellular cellulase. Phylogenetic and homology matrix analyses of DNA and protein sequences revealed that family 12 cellulase enzymes Cel12A and Cel12B displayed higher homology (>50 %), but Cel5C and Cel5D enzymes belong to family 5 displayed lower homology (<30 %). In addition, repeated and mirror sequences in tandem genes are supposed to show the existence of gene duplication and recombination. PMID:23001531

Kim, Min Keun; Kang, Tae Ho; Kim, Jungho; Kim, Hoon; Yun, Han Dae

2012-12-01

292

3D numerical modeling of wave forces on tandem fixed cylinders using the BEM  

NASA Astrophysics Data System (ADS)

In this paper a 3D numerical model was developed to study the complicated interaction between waves and a set of tandem fixed cylinders. The fluid was considered to be inviscid and irrotational. Therefore, the Helmholtz equation was used as a governing equation. The boundary element method (BEM) was adopted to discretize the relevant equations. Open boundaries were used in far fields of the study domain. Linear waves were generated and propagated towards tandem fixed cylinders to estimate the forces applied on them. Special attention was paid to consideration of the effect on varying non-dimensional cylinder radius and distance between cylinders, ka and kd on forces and trapped modes. The middle cylinder wave forces and trapped modes in a set of nine tandem cylinders were validated utilizing analytical data. The comparisons confirm the accuracy of the model. The results of the inline wave force estimation on n tandem cylinders show that the critical cylinder in the row is the middle one for odd numbers of cylinders. Furthermore the results show that the critical trapped mode effect occurs for normalized cylinder radiuses close to 0.5 and 1.0. Finally the force estimation for n tandem cylinders confirms that force amplitude of the middle cylinder versus normalized separation distance fluctuates about that of a single cylinder.

Ketabdari, Mohammad Javad; Abaiee, Mohammad Mahdi; Ahmadi, Ali

2013-09-01

293

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

2014-11-15

294

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

295

Simulation of two dimensional electrophoresis and tandem mass spectrometry for teaching proteomics.  

PubMed

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. The two simulations are integrated together and are designed to teach the concept of proteome analysis of prokaryotic and eukaryotic organisms. 2DE-Tandem MS can be used as a freestanding simulation, or in conjunction with a wet lab, to introduce proteomics in the undergraduate classroom. 2DE Tandem MS is a free program available on Sourceforge at https://sourceforge.net/projects/jbf/. It was developed using Java Swing and functions in Mac OSX, Windows, and Linux, ensuring that every student sees a consistent and informative graphical user interface no matter the computer platform they choose. Java must be installed on the host computer to run 2DE Tandem MS. Example classroom exercises are provided in the Supporting Information. PMID:23166029

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

2012-01-01

296

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

297

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

298

Monolithic, two-terminal InP/Ga[sub 0. 47]In[sub 0. 53]As tandem solar cells  

SciTech Connect

Monolithic InP/Ga[sub 0.7]In[sub 0.53]As tandem solar cells have been studied extensively in our laboratory over the last 4 years. Using the three-terminal approach, the tandem cell performance progressed rapidly, and improvements in the epitaxial growth and device processing procedures eventually led to a terrestrial concentrator tandem cell efficiency of 31.8%. Recently, our research has been directed towards the development of two-terminal (i.e., series-connected) monolithic InP/Ga[sub 0.47]In[sub 0.53]As tandem cells. Two-terminal tandem cells are desirable because they can he substituted directly for single-junction solar cells in photovoltaic module circuits that are being manufactured presently. Furthermore, in principle, two-terminal tandems should take less time to grow and process than three-terminal tandems, which would lead to reduced cell manufacturing costs. The data obtained from our previous study of three-terminal InP/Ga[sub 0.47]In[sub 0.53]As tandem cells have shown that the potential performance of two-terminal InP/Ga[sub 0.47]In[sub 0.53]As cells is quite high. Two fundamental problems must be addressed to realize high-performance, two-terminal cells. First, an ohmic electrical interconnect between the top and bottom subcells must be integrated into the monolithic structure to connect the subcells in series. The optical and joule losses in the interconnect should be negligible compared to the tandem cell output. Second, because the subcells are connected in series, techniques for matching the subcell photocurrents and maximizing the tandem cell photocurrent, under relevant solar spectra, are necessary to achieve the highest tandem cell efficiency. In this paper, we describe preliminary progress towards solving these problems and outline directions for future work.

Wanlass, M.W.; Ward, J.S.; Emery, K.A.; Coutts, T.J.

1993-01-01

299

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

300

Identification of the major selenium compound, Se-Methionine, in three yeast (Saccharomyces cerevisiae) dietary supplements by on-line narrowbore liquid chromatography-electrospray tandem mass spectrometry.  

PubMed

On-line monitoring of six Se-compounds was accomplished by using an XTerra MS C18 column coupled to electrospray tandem mass spectrometry (ES-MS-MS). In view of the nature of the compounds, the positively charged ion pairing agent tetraethylammoniumchloride (TEACl) was added to the mobile phase. The HPLC-ES-MS-MS method was optimized with six commercially available Se-compounds. Substitution of the analytical column by the narrowbore type significantly enhanced the sensitivity of the method. We were able to detect the m/z of these six molecules on-line. Furthermore, all product ions could be monitored. The method was applied to three different yeast-based supplements. They were submitted to proteolytic digestion and screened for their Se-content by HPLC-HG-AFS (hydride generation-atomic fluorescence spectrometry). By application of on-line narrowbore HPLC-electrospray tandem mass spectrometry, the main compound present in these three supplements, Se-Methionine, could be measured on its m/z and its product ions. The method can be further extended for on-line measurement of different Se-species in complex matrices PMID:15865193

Dumont, Emmie; De Cremer, Koen; Van Hulle, Marijn; Chéry, Cyrille C; Vanhaecke, Frank; Cornelis, Rita

2005-04-15

301

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

302

Complex evolution of tandem-repetitive DNA in the Chironomus thummi species group.  

PubMed

The subspecies Chironomus thummi thummi and C. t. piger display dramatic differences in the copy number and chromosomal localization of a tandemly repeated DNA family (Cla elements). In order to analyze the evolutionary dynamics of this repeat family, we studied the organization of Cla elements in the related outgroup species C. luridus. We find three different patterns of Cla element organization in C. luridus, showing that Cla elements may be either strictly tandem-repetitive or be an integral part of two higher-order tandem repeats (i.e., Hinf[lur] elements, Sal[lur] elements). All three types of Cla-related repeats are localized in the centromeres of C. luridus chromosomes. This suggests that the dispersed chromosomal localization of Cla elements in C. t. thummi may be the result of an amplification and transposition during evolution of this subspecies. PMID:9060398

Ross, R; Hankeln, T; Schmidt, E R

1997-03-01

303

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

304

Architecture, performance, and implementation of the tandem banyan fast packet switch  

NASA Technical Reports Server (NTRS)

The authors propose a space-division fast packet switch architecture based on banyan interconnection networks, called the tandem banyan switching fabric. It consists of placing banyan networks in tandem, offering multiple paths from each input to each output, thus overcoming in a very simple way the effect of conflicts among packets (to which banyan networks are prone) and achieving output buffering. From a hardware implementation perspective, this architecture is simple in that it consists of several instances of only two VLSI chips, one implementing the banyan network and the other implementing the output buffer function. The basic structure and operation of the tandem banyan switching fabric are described, and its performance is discussed. The authors propose a modification to the basic structure which decreases the hardware complexity of the switch while maintaining its performance. An implementation of the banyan network using a high-performance BiCMOS sea-of-gates on 0.8-micron technology is reported.

Tobagi, Fouad A.; Chiussi, Fabio M.; Kwok, Timothy

1991-01-01

305

Pt-free tandem molecular photoelectrochemical cells for water splitting driven by visible light.  

PubMed

Photoelectrochemical (PEC) cells using molecular catalysts to split water into hydrogen and oxygen have been investigated intensively during the past years. However, the high-cost of Pt counter electrodes and instability of molecular PEC cells hinder the practical applications. We describe in this article a Pt-free tandem molecular PEC cell, for the first time, employing molecular ruthenium- and cobalt-catalysts with strong dipicolinic acid anchoring groups on the respective photoanode and photocathode for total water splitting. The Pt-free tandem molecular PEC cell showed an effective and steady photocurrent density of ca. 25 ?A cm(-2) for water splitting driven by visible light without external bias. This study indicates that tandem molecular PEC cells can provide great potential to the Pt-free devices for light driven total water splitting. PMID:25341620

Fan, Ke; Li, Fusheng; Wang, Lei; Daniel, Quentin; Gabrielsson, Erik; Sun, Licheng

2014-12-14

306

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

307

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

308

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

309

Catalytic asymmetric tandem Friedel–Crafts alkylation/Michael addition reaction for the synthesis of highly functionalized chromans  

PubMed Central

Summary The enantioselective tandem Friedel–Crafts alkylation/Michael addition reaction of indoles with nitroolefin enoates catalyzed by a diphenylamine-linked bis(oxazoline)-Zn(OTf)2 complex was investigated. This tandem reaction afforded functionalized chiral chromans in good yields with moderate to high stereoselectivities (up to 95:5 dr, up to 99% ee). PMID:23843916

Peng, Jiahuan

2013-01-01

310

Chapter 3Synthesis of Tryptophan Derivatives 199 Synthesis of Tryptophan Derivatives by a Tandem FriedelCrafts  

E-print Network

that if catalyst- controlled protonation were operative, the related Friedel­Crafts alkylation reaction with C3 by a Tandem Friedel­Crafts Conjugate Addition/Enantioselective Protonation Reaction 3.1 INTRODUCTION During in the development of a tandem Friedel­Crafts conjugate addition/enantioselective Part of this chapter was published

Winfree, Erik

311

Catalytic asymmetric tandem Friedel-Crafts alkylation/Michael addition reaction for the synthesis of highly functionalized chromans.  

PubMed

The enantioselective tandem Friedel-Crafts alkylation/Michael addition reaction of indoles with nitroolefin enoates catalyzed by a diphenylamine-linked bis(oxazoline)-Zn(OTf)2 complex was investigated. This tandem reaction afforded functionalized chiral chromans in good yields with moderate to high stereoselectivities (up to 95:5 dr, up to 99% ee). PMID:23843916

Peng, Jiahuan; Du, Da-Ming

2013-01-01

312

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, flexible, wafer- free solar technology. Coupled full-field optical and device physics simulations of a Ga0

Atwater, Harry

313

Electrolytes Based on TEMPO-Co Tandem Redox Systems Outperform Single Redox Systems in Dye-sensitized Solar Cells.  

PubMed

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

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

2015-01-01

314

Aryl Ketone Synthesis via Tandem Orthoplatinated Triarylphosphite-Catalyzed Addition Reactions of Arylboronic Acids with Aldehydes Followed by Oxidation  

PubMed Central

Tandem orthoplatinated triarylphosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%. PMID:20849092

Liao, Yuan-Xi; Hu, Qiao-Sheng

2010-01-01

315

Aryl ketone synthesis via tandem orthoplatinated triarylphosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation.  

PubMed

Tandem orthoplatinated triaryl phosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%. PMID:20849092

Liao, Yuan-Xi; Hu, Qiao-Sheng

2010-10-15

316

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...

317

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

318

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

E-print Network

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

Feng, Jianfeng

319

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

320

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

321

Hydrogen photoevolution on InGaP polycrystalline and tandem-type electrodes  

NASA Astrophysics Data System (ADS)

We report on preparation of p-In1- x Ga x P polycrystalline, p-In0.5 Ga0.5P/p-GaAs, and p-In0.5 Ga0.5P/n-GaAs/n-InP tandem-type cathodes. The photovoltaic efficiency of InGaP tandem type epitaxial electrodes is two times higher than that of polycrystalline photocathodes. The most significant advantage of epitaxial electrodes is in their markedly better corrosion resistance in comparison with polycrystalline photocatodes.

Bludská, Jana; Jakubec, Ivo; Nohavica, Dušan; Pekárek, Ladislav

1999-05-01

322

An evaluation of a transient queueing approximation for M/M/1 and tandem queues  

E-print Network

AN EVAI, UATION OF A TRANSIENT QliEUEING APPROXIMATION FOR M/M(I AND TANDEM QUFUES A Thesis SIU-HUNG CHU Submitted to the Graduate College of Texas A&:M University in partial fulfillment, of the requirement for the degree of MASTER OF SCIENCF.... May 1985 Major Subject: Electrical Engineering AN EVALUATION OF A TRANSIENT QUEUEING APPROXIMATION FOR M/M/I AND TANDEM QUEUES A Thesis by SIU-HUNG CHU Approved as to style and content by: Fischer. Thomas R. (E. E) (Chairman of Committee...

Chu, Siu-Hung

2012-06-07

323

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

324

Gold-catalyzed tandem cycloisomerization/functionalization of in situ generated ?-oxo gold carbenes in water.  

PubMed

A gold-catalyzed tandem cycloisomerization/functionalization of in situ generated ?-oxo gold carbenes in water has been developed, which provides ready access to highly functionalized indole derivatives from o-alkynyl anilines and ynamides. Importantly, gold serves dual catalytic roles to mediate both the cycloisomerization of o-alkynyl anilines and the intermolecular oxidation of ynamides at the same time, thus providing a new type of concurrent tandem catalysis. The use of readily available starting materials, a simple procedure, and mild reaction conditions are other notable features of this method. PMID:25229883

Shen, Cang-Hai; Li, Long; Zhang, Wei; Liu, Shuang; Shu, Chao; Xie, Yun-Er; Yu, Yong-Fei; Ye, Long-Wu

2014-10-01

325

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

326

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

327

InGaAs series-connected, tandem, MIM TPV converters  

Microsoft Academic Search

Thermophotovoltaic (TPV) tandem converter technology is being explored in an effort to improve the efficiency of TPV systems while maintaining high power densities. Series-connected (SC) tandem structures incorporate epitaxially grown 0.74 eV lattice-matched Ga\\/sub 0.47\\/In\\/sub 0.53\\/As and 0.63 eV lattice-mismatched Ga\\/sub 0.36\\/In\\/sub 0.64\\/As diodes. Structures have been grown using OMVPE and devices have been fabricated via wet-chemical processing. The 10-cell

R. Wehrer; M. Wanlass; David Wilt; B. Wernsman; R. Siergiej; J. Carapella

2003-01-01

328

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

329

Stir bar sorptive extraction coupled to liquid chromatography-tandem mass spectrometry for the2 determination of pesticides in water samples: method validation and measurement uncertainty3  

E-print Network

1 Title :1 Stir bar sorptive extraction coupled to liquid chromatography-tandem mass spectrometry sorptive extraction followed by liquid desorption and high performance liquid12 chromatography with tandem chromatography-tandem mass spectrometry (LC-30 MSMS), pesticides, surface water, validation, measurement

Paris-Sud XI, Université de

330

Digital genotyping of macrosatellites and multicopy genes reveals novel biological functions associated with copy number variation of large tandem repeats.  

PubMed

Tandem repeats are common in eukaryotic genomes, but due to difficulties in assaying them remain poorly studied. Here, we demonstrate the utility of Nanostring technology as a targeted approach to perform accurate measurement of tandem repeats even at extremely high copy number, and apply this technology to genotype 165 HapMap samples from three different populations and five species of non-human primates. We observed extreme variability in copy number of tandemly repeated genes, with many loci showing 5-10 fold variation in copy number among humans. Many of these loci show hallmarks of genome assembly errors, and the true copy number of many large tandem repeats is significantly under-represented even in the high quality 'finished' human reference assembly. Importantly, we demonstrate that most large tandem repeat variations are not tagged by nearby SNPs, and are therefore essentially invisible to SNP-based GWAS approaches. Using association analysis we identify many cis correlations of large tandem repeat variants with nearby gene expression and DNA methylation levels, indicating that variations of tandem repeat length are associated with functional effects on the local genomic environment. This includes an example where expansion of a macrosatellite repeat is associated with increased DNA methylation and suppression of nearby gene expression, suggesting a mechanism termed "repeat induced gene silencing", which has previously been observed only in transgenic organisms. We also observed multiple signatures consistent with altered selective pressures at tandemly repeated loci, suggesting important biological functions. Our studies show that tandemly repeated loci represent a highly variable fraction of the genome that have been systematically ignored by most previous studies, copy number variation of which can exert functionally significant effects. We suggest that future studies of tandem repeat loci will lead to many novel insights into their role in modulating both genomic and phenotypic diversity. PMID:24945355

Brahmachary, Manisha; Guilmatre, Audrey; Quilez, Javier; Hasson, Dan; Borel, Christelle; Warburton, Peter; Sharp, Andrew J

2014-06-01

331

Digital Genotyping of Macrosatellites and Multicopy Genes Reveals Novel Biological Functions Associated with Copy Number Variation of Large Tandem Repeats  

PubMed Central

Tandem repeats are common in eukaryotic genomes, but due to difficulties in assaying them remain poorly studied. Here, we demonstrate the utility of Nanostring technology as a targeted approach to perform accurate measurement of tandem repeats even at extremely high copy number, and apply this technology to genotype 165 HapMap samples from three different populations and five species of non-human primates. We observed extreme variability in copy number of tandemly repeated genes, with many loci showing 5–10 fold variation in copy number among humans. Many of these loci show hallmarks of genome assembly errors, and the true copy number of many large tandem repeats is significantly under-represented even in the high quality ‘finished’ human reference assembly. Importantly, we demonstrate that most large tandem repeat variations are not tagged by nearby SNPs, and are therefore essentially invisible to SNP-based GWAS approaches. Using association analysis we identify many cis correlations of large tandem repeat variants with nearby gene expression and DNA methylation levels, indicating that variations of tandem repeat length are associated with functional effects on the local genomic environment. This includes an example where expansion of a macrosatellite repeat is associated with increased DNA methylation and suppression of nearby gene expression, suggesting a mechanism termed “repeat induced gene silencing”, which has previously been observed only in transgenic organisms. We also observed multiple signatures consistent with altered selective pressures at tandemly repeated loci, suggesting important biological functions. Our studies show that tandemly repeated loci represent a highly variable fraction of the genome that have been systematically ignored by most previous studies, copy number variation of which can exert functionally significant effects. We suggest that future studies of tandem repeat loci will lead to many novel insights into their role in modulating both genomic and phenotypic diversity. PMID:24945355

Quilez, Javier; Hasson, Dan; Borel, Christelle; Warburton, Peter; Sharp, Andrew J.

2014-01-01

332

Quantitative determination of nebivolol from human plasma using liquid chromatography-tandem mass spectrometry.  

PubMed

In the present work, a rapid, sensitive, specific, precise and accurate liquid chromatography-tandem mass spectrometry method for determination of nebivolol in human plasma was developed and validated with a large calibration curve range (50-5000 pg/mL) which can be used for routine drug analysis and bioequivalence studies. Liquid-liquid extraction method was used to extract the analyte from the human plasma. The separation was achieved using Waters symmetry, C18, 4.6 × 150 mm, 5 ?m column with formic acid in water, 0.01%, v/v: Acetonitrile (40:60) as a mobile phase. A flow rate of 0.8 mL/min, no splitting and run time 2.00 min was used for the chromatographic analysis of nebivolol. Sensitivity of this method was found to be 30 pg/mL. The analyte was analyzed by mass spectrometry in the multiple reaction monitoring mode. A Turbo-Ion spray source was interfaced between the HPLC and triple quadrupole mass spectrometer (MDS Sciex API 4000). The precursor-product ion m/z 406.00-151.00 for nebivolol and m/z 410.20-151.00 for nebivolol-D4 were used for quantification of an analyte and its IS. The method was validated in terms of accuracy, precision, selectivity, absolute recovery, freeze-thaw stability, bench-top stability, dry extract stability, short and long term stock solution stability, wet extract stability and re-injection reproducibility. The within- and between-batch accuracy was found to lie within the range of 87.00-100.40% and within- and between-batch precision was obtained within the range 0.33-8.67%. The mean recovery of all three concentration levels for drug was obtained 67.67% where as the mean recovery of IS was 68.74%. The %RSD value at higher concentration and lower concentration in all stability experiments was within 15%. This method is free from ion suppression, ion enhancement and any type of abnormal ionization. PMID:23500355

Nandania, Jatin; Rajput, S J; Contractor, Pritesh; Vasava, Pragnesh; Solanki, Bhavik; Vohra, Mohsin

2013-04-01

333

Determination of perhexiline and its metabolite hydroxyperhexiline in human plasma by liquid chromatography/tandem mass spectrometry.  

PubMed

Perhexiline is a drug that is used for treatment of moderate to severe angina pectoris that has not responded to other treatment. It has a low therapeutic index, and saturable metabolism that is also subject to genetic polymorphism (CYP2D6). Concentration monitoring of the parent drug and its major metabolite is considered necessary to optimise efficacy and reduce the risk of hepatotoxicity and neuropathy. A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of perhexiline and its metabolite cis-hydroxyperhexiline in human plasma. After proteins were precipitated with acetonitrile, perhexiline, the major metabolite cis-hydroxyperhexiline and nordoxepin as the internal standard were resolved on a phenyl-hexyl column using gradient elution of 0.05% formic acid and methanol. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves were linear over the concentration range 10-2000microg/L (r>0.999), bias was enhance the safe and effective use of perhexiline. PMID:19646935

Zhang, Mei; Moore, Grant A; Barclay, Murray L; Begg, Evan J

2009-10-01

334

Detection of peginesatide in equine serum using liquid chromatography-tandem mass spectrometry for doping control purposes.  

PubMed

Erythropoietin (EPO) and its recombinant analogues are suspected to be illicitly administered to horses for performance enhancing purposes and, consequently, prohibited in equine sports. Recently, a new erythropoiesis-stimulating agent, peginesatide (Omontys, formerly referred to as Hematide), belonging to the upcoming class of EPO-mimetic peptides, received approval for the treatment of anaemia in humans with chronic kidney disease on dialysis. As the pegylated dimeric peptide of approximately 45 kDa without sequence homology to EPO is not detectable by conventional EPO detection assays, specific methods are bound to be established for horse sports drug testing. Thus, by fortifying equine serum with peginesatide, an approach consisting of a proteolytic digestion with subtilisin after protein precipitation was developed, eventually targeting a proteotypic and xenobiotic pentapeptide which is easily accessible to liquid chromatography- tandem mass spectrometry analysis. The method was validated for qualitative purposes and demonstrated to be specific, precise (relative standard deviations below 14%), sensitive (limit of detection 10 ng mL(-1)) and linear. Being simple, cost-effective and readily transferable to other doping control laboratories, a mass spectrometric assay for the detection of therapeutic concentrations of peginesatide in equine serum is, in terms of preventive doping research, applicable to routine analysis shortly after approval of the drug. PMID:22971699

Möller, Ines; Thomas, Andreas; Wingender, Anke; Machnik, Marc; Schänzer, Wilhelm; Thevis, Mario

2012-01-01

335

Detection of buffalo mozzarella adulteration by an ultra-high performance liquid chromatography tandem mass spectrometry methodology.  

PubMed

Over the past years, LC-MS-based approaches have gained a growing interest in food analysis by using different platforms and methodologies. In particular, enhanced selectivity and sensitivity of multiple reaction monitoring (MRM) scan function offer powerful capabilities in detecting and quantifying specific analytes within complex mixtures such as food matrices. The MRM approach, traditionally applied in biomedical research, is particularly suitable for the detection of food adulteration and for the verification of authenticity to assure food safety and quality, both recognized as top priorities by the European Union Commission. Increasingly stringent legislation ensure products safety along every step 'from farm to fork', especially for traditional foods designed with the Protected Designation of Origin certification. Therefore, there is a growing demand of new methodologies for defining food authenticity in order to preserve their unique traits against frauds. In this work, an ultra performance liquid chromatopgraphy-electrospray ionization-tandem mass spectrometry (MS/MS) methodology based on MRM has been developed for the sensitive and selective detection of buffalo mozzarella adulteration. The targeted quantitative analysis was performed by monitoring specific transitions of the phosphorylated ?-casein f33-48 peptide, identified as a novel species-specific proteotypic marker. The high sensitivity of MRM-based MS and the wide dynamic range of triple quadrupole spectrometers have proved to be a valuable tool for the analysis of food matrices such as dairy products, thus offering new opportunities for monitoring food quality and adulterations. PMID:23147815

Russo, Rosita; Severino, Valeria; Mendez, Alberto; Lliberia, Josep; Parente, Augusto; Chambery, Angela

2012-11-01

336

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

337

PROTEIN-PROTEIN INTERACTIONS OF TANDEM AFFINITY PURIFICATION (TAP)-TAGGED PROTEIN KINASES IN RICE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Forty-one rice cDNAs encoding protein kinases were fused to the tandem affinity purification (TAP) tag and expressed in transgenic rice plants. The TAP-tagged kinases and interacting proteins were purified from the T1 progeny of the transgenic rice plants and identified by mass spectrometry. Ninet...

338

Genetic Individualization of Cannabis sativa by a Short Tandem Repeat Multiplex System  

Microsoft Academic Search

Cannabis sativa is the most frequently used of all illicit drugs in the United States. Cannabis has been used throughout history for its stems in the production of hemp fiber, for its seed for oil and food, and for its buds and leaves as a psychoactive drug. Short tandem repeats (STRs), were chosen as molecular markers because of their distinct

Maria Angelica Mendoza Baez

2008-01-01

339

Genetic individualization of Cannabis sativa by a short tandem repeat multiplex system  

Microsoft Academic Search

Cannabis sativa is the most frequently used of all illicit drugs in the United States. Cannabis has been used throughout history for its stems in the production of hemp fiber, for its seed for oil and food, and for its buds and leaves as a psychoactive drug. Short tandem repeats (STRs), were chosen as molecular markers because of their distinct

Maria Angelica Mendoza Baez

2008-01-01

340

Broader pattern of tandem repeats in the mitochondrial control region of Perciformes  

NASA Astrophysics Data System (ADS)

Perciformes, the largest order of vertebrates with 20 suborders, is the most diverse fish order that dominates vertebrate ocean life. The complete mitochondrial control region (CR) of Trichiurus japonicus (Trichiuridae, Scombroidei) and Pampus sp. (Stromateidae, Stromateoidei) were amplified and sequenced. Together with data from GenBank, the tandem repeats in the mitochondrial CR from 48 species, which covered nine suborders of Perciformes, are reported in this study. The tandem repeats tend to be long in the suborder Percoidei and Stromateoidei. The identical repeats in 21 species of Cichlidae suggest a common origin and have existed before species divergence. Larimichthys crocea shows tandem repeats instead of the typical structure of the central conserved sequence blocks, which was first reported in Perciformes and vertebrates. This might have resulted from interruption of the polymerase activity during the H-strand synthesis. The four broader patterns presented here for the tandem repeats, including those in both the 5' and 3' ends, only in the either 5' or 3' end, and in the central conserved domain of the control region, will be useful for understanding the evolution of species.

Cui, Zhaoxia; Liu, Yuan; Chu, Ka Hou

2010-07-01

341

Final version of the pick-up wheels in the Pelletron tandem accelerator at Lund  

NASA Astrophysics Data System (ADS)

A new type of pick-up wheel has been designed and constructed for the charge transport system of the Lund 3UDH Pelletron tandem accelerator. The major improvements compared with older types are a slender design with only one ball bearing and more robust contact pins with a rubber ring between the pinhead and the wheel nave.

Håkansson, Kjell; Hellborg, Ragnar

1993-04-01

342

The heterochronic maize mutant Corngrass1 results from overexpression of a tandem microRNA  

Technology Transfer Automated Retrieval System (TEKTRAN)

We cloned Cg1 and found that it encodes two tandem miR156 genes that are over expressed in the meristem and lateral organs. Furthermore, a target of Cg1 is teosinte glume architecture11, a gene known to have played a role in the domestication of maize from teosinte. Cg1 mutant plants overexpressing ...

343

Multicatalytic tandem reaction of N'-(2-alkynylbenzylidene)hydrazide with indole.  

PubMed

The combination of AgOTf and Dy(OTf)(3) shows high efficiency as a catalyst in the tandem reactions of N'-(2-alkynylbenzylidene)hydrazides with indoles, which generate the unexpected 1-(indol-3-yl)-2-aminoisoquinolinium triflates in good yields. PMID:19830305

Yu, Xingxin; Yang, Xiaodi; Wu, Jie

2009-11-01

344

Combined Dynamic Arrays for Storing and Searching Semi-Ordered Tandem Mass Spectrometry Data  

Technology Transfer Automated Retrieval System (TEKTRAN)

When performing bioinformatics analysis on tandem mass spectrometry data, there is a computational need to efficiently store and sort these semi-ordered data sets. To solve this problem, a new data structure based on dynamic arrays was designed and implemented in an algorithm that parses semi-order...

345

Identification and Characterization of Variable-Number Tandem Repeats in the Yersinia pestis Genome  

Microsoft Academic Search

Yersinia pestis, the infamous plague-causing pathogen, appears to have emerged in relatively recent history. Evidence of this fact comes from several studies that document a lack of nucleotide diversity in the Y. pestis ge- nome. In contrast, we report that variable-number tandem repeat (VNTR) sequences are common in the Y. pestis genome and occur frequently in gene coding regions. Larger

ALEXANDRA M. KLEVYTSKA; LANCE B. PRICE; JAMES M. SCHUPP; PATRICIA L. WORSHAM; JANE WONG; PAUL KEIM; Fort Detrick

2001-01-01

346

Ion-retarding lens improves the abundance sensitivity of tandem mass spectrometers  

NASA Technical Reports Server (NTRS)

Ion-retarding lens which increases the abundance sensitivity of tandem magnetic-analyzer mass spectrometers measures isotopes of low abundance in mass positions adjacent to isotopes of high abundance. The lens increases the abundance sensitivity for isotopes lying farther from high abundance isotopes than the energy cutoff of the lens.

Kaiser, K. A.; Stevens, C. M.

1969-01-01

347

Functional b-propeller lectins by tandem duplications of repetitive units  

E-print Network

Functional b-propeller lectins by tandem duplications of repetitive units Itamar Yadid and Dan S proteins, b-propellers, which are made of 4­10 b-sheet units (blades) circularly arranged around a central- ducing the evolution of functional b-propellers by dupli- cation and fusion of repeated units remains

Tawfik, Dan S.

348

In situ fabrication of polyacrylate-silver nanocomposite through photoinduced tandem reactions involving eosin dye  

E-print Network

1 In situ fabrication of polyacrylate-silver nanocomposite through photoinduced tandem reactions Corresponding authors: lavinia.balan@uha.fr ABSTRACT A silver-acrylate nanocomposite was prepared using a novel-situ fabrication method, the kinetics formation of the nanocomposite and its detailed structural analysis

Paris-Sud XI, Université de

349

Synthesis of substituted azafluorenones from dihalogeno diaryl ketones by palladium-catalyzed auto-tandem processes.  

PubMed

Substituted azafluorenones were synthesized from different dihalogeno diaryl ketones under palladium catalysis by combining either Suzuki or Heck coupling with direct cyclizing arylation. Conditions were identified to allow both auto-tandem processes to proceed successfully from 3-(bromobenzoyl)- or 3-benzoyl-4-bromo-2-chloropyridines, as well as 4-benzoyl-2,3- and 4-benzoyl-2,5-dichloropyridines. PMID:25233952

Marquise, Nada; Dorcet, Vincent; Chevallier, Floris; Mongin, Florence

2014-11-01

350

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

351

Tandem Synthesis of 3-Halo-5-Substituted Isoxazoles from 1-Copper(I) Alkynes and Dihaloformaldoximes.  

PubMed

A tandem synthesis of 3-halo-5-substituted isoxazoles has been developed from 1-copper(I) alkynes and dihaloformaldoximes under base-free conditions. Thus, 1,3-dipolar cycloaddition and all its drawbacks can now be avoided completely. PMID:25397915

Chen, Wenwen; Wang, Bo; Liu, Nan; Huang, Dayun; Wang, Xinyan; Hu, Yuefei

2014-11-14

352

In Two Minds? Learner Attitudes to Bilingualism and the Bilingual Tandem Analyser  

ERIC Educational Resources Information Center

One of the issues that has been debated in the context of fairly open learning partnerships such as tandem learning has been whether and, if so, how much pedagogical support should be provided. Another issue is how do language learners who have grown accustomed to maximising their learning through comprehensible input and output make the…

Kapec, Peter; Schwienhorst, Klaus

2005-01-01

353

Pyridone Annulation via Tandem Curtius Rearrangement/6?-Electrocyclization: Total Synthesis of (?)-Lyconadin C  

PubMed Central

A concise, enantioselective total synthesis of the Lycopodium alkaloid (?)-lyconadin C was achieved in 12 steps and high overall yield. Key features include construction of a luciduline congener through Mannich-type cyclization and a one-pot, tandem Curtius rearrangement/6?-electrocyclization to fashion the 2-pyridone system of lyconadin C. PMID:23909645

Cheng, Xiayun

2013-01-01

354

Design, characterization and fabrication of silicon solar cells for ?50% efficient 6-junction tandem solar cells  

Microsoft Academic Search

A major objective for photovoltaic conversion is to develop high efficiency solar cells. Many approaches are under investigation - Multiple Junction Solar Cell, Multiple Spectrum Solar Cell, Multiple Absorption Path Solar Cell, Multiple Energy Solar Cell, and Multiple Temperature Solar Cells [1]. The Multiple Junction Solar Cell approach based on a six-junction tandem solar cell has been adopted to achieve

Ngwe Soe Zin; Andrew Blakers; Evan Franklin; Vernie Everett

2008-01-01

355

RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.  

EPA Science Inventory

In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

356

-7. Mol. Biol. (1978) 119, 147-166 Tandem Chromosomal Duplications in Salmonella typhimurium  

E-print Network

-7. Mol. Biol. (1978) 119, 147-166 Tandem Chromosomal Duplications in Salmonella typhimurium University of Utah ASalt Lake City, Utah 84112, U.S'.A. (Received 16 August 1977) Salmonella strains are merodiploid for large regions (up to 25%) of the Salmonella genome. (4) Recipient strains that inherit the His

California at Davis, University of

357

J. Mol. Biol. (1978) 126, 53-71 Tandem Genetic Duplications in Salmonella typhimurium  

E-print Network

J. Mol. Biol. (1978) 126, 53-71 Tandem Genetic Duplications in Salmonella typhimurium AND .I. R. ROTH co& and Salmonella typhimurium (Langridge. 1969; Miller $ Roth. 1971; Hill & Combriato of the histidine operon in Salmonella have previously been described. One is based upon the ability of duplica

California at Davis, University of

358

MEASUREMENT OF OXIDATIVE STRESS PARAMETERS USING LIQUID CHROMATOGRAPHY - TANDEM MASS SPECTROSCOPY (LC-MS/MS)  

EPA Science Inventory

What is the study? An invited review article. Measurement of oxidative stress parameters using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) Why was it done? Although oxidative stress is frequently cited as a cause of various adverse biological eff...

359

Cooperative activity of cdk8 and GCN5L within Mediator directs tandem phosphoacetylation  

E-print Network

Cooperative activity of cdk8 and GCN5L within Mediator directs tandem phosphoacetylation of histone of protein-coding genes. Here, we show that the GCN5L acetyltransferase stably associates with Mediator together with the TRRAP polypeptide. Yet, contrary to expectations, TRRAP/GCN5L does not associ- ate

360

Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing  

Microsoft Academic Search

Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiOx) layer separates and connects the front cell and the back cell.

Jin Young Kim; Kwanghee Lee; Nelson E. Coates; Daniel Moses; Thuc-Quyen Nguyen; Mark Dante; Alan J. Heeger

2007-01-01

361

Detecting short tandem repeats from genome data: opening the software black box  

Microsoft Academic Search

Short tandem repeats, specifically microsatellites, are widely used genetic markers, associated with human genetic diseases, and play an important role in various regulatory mechanisms and evolution. Despite their importance, much is yet unknown about their mutational dynamics. The increasing availability of genome data has led to several in silico studies of microsatellite evolution which have produced a vast range of

Angelika Merkel; Neil Gemmell

2008-01-01

362

Sensitive, Preclinical Detection of Prions in Brain by nanospray liquid chromatography/tandem mass spectrometry  

Technology Transfer Automated Retrieval System (TEKTRAN)

More sensitive detection of prions in brain is important because it would allow early detection of disease in young animals and assure a safer food supply. We quantitated the amount of proteinase K-resistant prion protein (PrP 27-30) by use of nano-scale liquid chromatography coupled to a tandem ma...

363

Multiple-Locus Variable-Number Tandem Repeat Analysis Reveals Genetic Relationships within Bacillus anthracis  

Microsoft Academic Search

Bacillus anthracis is one of the most genetically homogeneous pathogens described, making strain discrim- ination particularly difficult. In this paper, we present a novel molecular typing system based on rapidly evolving variable-number tandem repeat (VNTR) loci. Multiple-locus VNTR analysis (MLVA) uses the com- bined power of multiple alleles at several marker loci. In our system, fluorescently labeled PCR primers are

P. Keim; L. B. Price; A. M. Klevytska; K. L. Smith; J. M. Schupp; R. Okinaka; P. J. Jackson; M. E. Hugh-Jones

2000-01-01

364

Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer.  

PubMed

Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution, high spectral resolution, and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror, it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating, which make the anterior Wadsworth condition fulfilling each wavelength, is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. PMID:23292378

Lei, Yu; Lin, Guan-yu

2013-01-01

365

RESEARCH Open Access Real-time PCR detection of the HhaI tandem DNA  

E-print Network

RESEARCH Open Access Real-time PCR detection of the HhaI tandem DNA repeat in pre- and post are required. Methods: An optimized real-time PCR targeting the brugian HhaI repeat was validated with plasma, amicrofilaremic, real-time PCR, HhaI, pre-patent, detection Background Lymphatic filariasis (LF) affects

366

Characterization of Tandem Repeats and Repetitive Elements in the Genomes of Mycosphaerella graminicola and M. figiensis  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the genome of Mycosphaerella graminicola, the causal agent of septoria leaf blotch of wheat, a total of 22745 tandem repeat sites at least 15 bp in length were isolated for motifs from two to 250 bases long by the same processing pipeline that we have used to analyze such repeats in plant EST col...

367

Molecular Resolution and Fragmentation of Fulvic Acid by Electrospray Ionization/Multistage Tandem  

E-print Network

of nutrients for plant growth,1 in the formation and maintenance of good soil structure,1 and in their reactionMolecular Resolution and Fragmentation of Fulvic Acid by Electrospray Ionization/Multistage Tandem distributions of fulvic acid from the Suwannee River, Georgia, were investigated by electro- spray ionization

368

IDENTIFICATION OF FLAVONE AGLYCONES AND GLYCOSIDES IN SOYBEAN PODS BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

High-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS) was used to identify flavone aglycones and glycosides in soybean pods. Tandem mass spectrometry (MS/MS and MS3) and photodiode array detection were also utilized in flavone characterizat...

369

Highly efficient tandem polymer solar cells with a photovoltaic response in the visible light range.  

PubMed

Highly efficient polymer solar cells with a tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion -efficiencies over 10% can be realized with a photovoltaic response within 800 nm. PMID:25530506

Zheng, Zhong; Zhang, Shaoqing; Zhang, Maojie; Zhao, Kang; Ye, Long; Chen, Yu; Yang, Bei; Hou, Jianhui

2015-02-01

370

Expression Analysis of ABC Transporters Reveals Differential Functions of Tandemly Duplicated Genes in  

E-print Network

in humans or in hyper- sensitivity to drugs. For example, mutations in the ABCA1 gene cause very low levelsExpression Analysis of ABC Transporters Reveals Differential Functions of Tandemly Duplicated Genes, BC Canada V5Z 1L6 We have previously identified 60 predicted ABC transporter genes

Baillie, David

371

Status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostic system  

SciTech Connect

This paper presents the current status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics system. For the initial instruments active on TMX-U, the expansions or upgrades that have been implemented are outlined. For the newly added systems, more implementation details are presented.

Coutts, G.W.; Coffield, F.E.; Hornady, R.S.

1983-11-26

372

Internal combustion engine with a central crankshaft and integral tandem annular pistons  

Microsoft Academic Search

An internal combustion engine with tandem annular pistons and a central crankshaft is disclosed, based on that found in British patent 11027 of 11 May 1914. The piston block formed by the two pistons presents, at each axial extremity, a double axial skirt fitted with an outer crown forming the head of the piston as such, and an inner crown

Bernard Esparbes

1993-01-01

373

Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in  

E-print Network

in a multiplex fashion to measure sev- eral lysosomal enzymes relevant to treatable lysosomal storage diseases. Mucopolysaccharidosis type I (MPS-I)4 is a lysosomal storage disorder caused by the deficiency of -L- iduronidase (IdTandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in Dried Blood Spots

Gelb, Michael

374

Modelling single- and tandem-bubble dynamics between two parallel plates for biomedical applications.  

PubMed

Carefully timed tandem microbubbles have been shown to produce directional and targeted membrane poration of individual cells in microfluidic systems, which could be of use in ultrasound-mediated drug and gene delivery. This study aims at contributing to the understanding of the mechanisms at play in such an interaction. The dynamics of single and tandem microbubbles between two parallel plates is studied numerically and analytically. Comparisons are then made between the numerical results and the available experimental results. Numerically, assuming a potential flow, a three-dimensional boundary element method (BEM) is used to describe complex bubble deformations, jet formation, and bubble splitting. Analytically, compressibility and viscous boundary layer effects along the channel walls, neglected in the BEM model, are considered while shape of the bubble is not considered. Comparisons show that energy losses modify the bubble dynamics when the two approaches use identical initial conditions. The initial conditions in the boundary element method can be adjusted to recover the bubble period and maximum bubble volume when in an infinite medium. Using the same conditions enables the method to recover the full dynamics of single and tandem bubbles, including large deformations and fast re-entering jet formation. This method can be used as a design tool for future tandem-bubble sonoporation experiments. PMID:24293683

Hsiao, C-T; Choi, J-K; Singh, S; Chahine, G L; Hay, T A; Ilinskii, Yu A; Zabolotskaya, E A; Hamilton, M F; Sankin, G; Yuan, F; Zhong, P

2013-02-01

375

Pyridone annulation via tandem Curtius rearrangement/6?-electrocyclization: total synthesis of (-)-lyconadin C.  

PubMed

A concise, enantioselective total synthesis of the Lycopodium alkaloid (-)-lyconadin C was achieved in 12 steps and high overall yield. Key features include construction of a luciduline congener through Mannich-type cyclization and a one-pot, tandem Curtius rearrangement/6?-electrocyclization to fashion the 2-pyridone system of lyconadin C. PMID:23909645

Cheng, Xiayun; Waters, Stephen P

2013-08-16

376

Heat-pipe liquid-pool-blanket concept for the Tandem Mirror Reactor  

SciTech Connect

The blanket concept for the tandem mirror reactor described in this paper was developed to produce the medium temperature heat (approx. 850 to 950 K) for the General Atomic sulfur-iodine thermochemical process for producing hydrogen. This medium temperature heat from the blanket constitutes about 81% of the total power output of the fusion reactor.

Hoffman, M.A.; Werner, R.W.; Johnson, G.L.

1981-10-01

377

STRUCTURAL CHARACTERIZATION OF SULFONATED AZO DYES USING LIQUID SECONDARY ION MASS SPECTROMETRY/TANDEM MASS SPECTROMETRY  

EPA Science Inventory

Eight monosulfonated and disulfonated azo dyes were analyzed using liquid secondary ion mass spectrometry/tandem mass spectrometry, in the negative ion mode, under low-energy conditions (110-150 eV). any structurally characteristic fragment ions were obtained, several of which ha...

378

STRUCTURAL CHARACTERIZATION OF REACTIVE DYES USING SECONDARY ION MASS SPECTROMETRY/TANDEM MASS SPECTROMETRY  

EPA Science Inventory

Reactive Blue 19 (RB 19), its reactive form (RB 19-VS) and its hydrolyzed form, (RB 19-OH) were examined using liquid secondary ion mass spectrometry/tandem mass spectrometry (LSIMS/MS/MS) in the negative-ion mode under low-energy collision conditions (240-300 eV). tructurally ch...

379

Analyzing proteomes and protein function using graphical comparative analysis of tandem mass spectrometry results.  

PubMed

Although generating large amounts of proteomic data using tandem mass spectrometry has become routine, there is currently no single set of comprehensive tools for the rigorous analysis of tandem mass spectrometry results given the large variety of possible experimental aims. Currently available applications are typically designed for displaying proteins and posttranslational modifications from the point of view of the mass spectrometrist and are not versatile enough to allow investigators to develop biological models of protein function, protein structure, or cell state. In addition, storage and dissemination of mass spectrometry-based proteomic data are problems facing the scientific community. To address these issues, we have developed a relational database model that efficiently stores and manages large amounts of tandem mass spectrometry results. We have developed an integrated suite of multifunctional analysis software for interpreting, comparing, and displaying these results. Our system, Bioinformatic Graphical Comparative Analysis Tools (BIGCAT), allows sophisticated analysis of tandem mass spectrometry results in a biologically intuitive format and provides a solution to many data storage and dissemination issues. PMID:16707483

McAfee, K Jill; Duncan, Dexter T; Assink, Michael; Link, Andrew J

2006-08-01

380

Variable-number tandem repeats as molecular markers for biotypes of Pasteuria ramosa in Daphnia spp.  

PubMed

Variable-number tandem repeats (VNTRs) have been identified in populations of Pasteuria ramosa, a castrating endobacterium of Daphnia species. The allelic polymorphisms at 14 loci in laboratory and geographically diverse soil samples showed that VNTRs may serve as biomarkers for the genetic characterization of P. ramosa isolates. PMID:17400766

Mouton, Laurence; Nong, Guang; Preston, James F; Ebert, Dieter

2007-06-01

381

Variable-Number Tandem Repeats as Molecular Markers for Biotypes of Pasteuria ramosa in Daphnia spp.?  

PubMed Central

Variable-number tandem repeats (VNTRs) have been identified in populations of Pasteuria ramosa, a castrating endobacterium of Daphnia species. The allelic polymorphisms at 14 loci in laboratory and geographically diverse soil samples showed that VNTRs may serve as biomarkers for the genetic characterization of P. ramosa isolates. PMID:17400766

Mouton, Laurence; Nong, Guang; Preston, James F.; Ebert, Dieter

2007-01-01

382

Analytical study on plate edge noise (Noise generation from tandemly situated trailing and leading edges)  

Microsoft Academic Search

The problem of noise generation due to the interaction between flows and plate edges is treated analytically. In uniform flow containing vorticity waves, two semiinfinite flat plates are placed with the trailing edge of one plate and leading edge of the other being tandemly situated a finite distance apart. This flow is considered to be a simplified model for self-excited

Koji Takahashi; Shojiro Kaji

1993-01-01

383

Analysis of impurity diffusion from tunnel diodes and optimization for operation in tandem cells  

Microsoft Academic Search

The tunnel diode has been applied as an interconnector in monolithic devices such as tandem solar cells. However, thermal degradation due to impurity diffusion is often observed due to growth at above about 600°C. In this study, the impurity diffusion from highly doped tunnel junctions after annealing has been analyzed, and it has been suggested that carbon has the advantage

Nobuaki Kojima; Masaki Okamoto; Stephen J. Taylor; Ming-Ju Yang; Tatsuya Takamoto; Masafumi Yamaguchi; Ken Takahashi; Tsunehiro Unno

1998-01-01

384

Identification of the antidiarrhoeal components in official rhubarb using liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Though the purgative components in official rhubarb are well documented as anthraquinone glycosides and sennosides, the antidiarrhoeal effect and its chemical basis have not been reported before. In this study, liquid chromatography coupled with electrospray ionisation tandem mass spectrometry was used to investigate the main chemicals in the antidiarrhoeal fraction previously isolated from Rheum palmatum L. In total 10 compounds

Jia-bo Wang; Yi Qin; Wei-jun Kong; Zhe-wei Wang; Ling-na Zeng; Fang Fang; Cheng Jin; Yan-ling Zhao; Xiao-he Xiao

2011-01-01

385

Modelling single- and tandem-bubble dynamics between two parallel plates for biomedical applications  

PubMed Central

Carefully timed tandem microbubbles have been shown to produce directional and targeted membrane poration of individual cells in microfluidic systems, which could be of use in ultrasound-mediated drug and gene delivery. This study aims at contributing to the understanding of the mechanisms at play in such an interaction. The dynamics of single and tandem microbubbles between two parallel plates is studied numerically and analytically. Comparisons are then made between the numerical results and the available experimental results. Numerically, assuming a potential flow, a three-dimensional boundary element method (BEM) is used to describe complex bubble deformations, jet formation, and bubble splitting. Analytically, compressibility and viscous boundary layer effects along the channel walls, neglected in the BEM model, are considered while shape of the bubble is not considered. Comparisons show that energy losses modify the bubble dynamics when the two approaches use identical initial conditions. The initial conditions in the boundary element method can be adjusted to recover the bubble period and maximum bubble volume when in an infinite medium. Using the same conditions enables the method to recover the full dynamics of single and tandem bubbles, including large deformations and fast re-entering jet formation. This method can be used as a design tool for future tandem-bubble sonoporation experiments. PMID:24293683

Hsiao, C.-T.; Choi, J.-K.; Singh, S.; Chahine, G. L.; Hay, T. A.; Ilinskii, Yu. A.; Zabolotskaya, E. A.; Hamilton, M. F.; Sankin, G.; Yuan, F.; Zhong, P.

2013-01-01

386

An Exact and Polynomial Distance-Based Algorithm to Reconstruct Single Copy Tandem Duplication Trees  

Microsoft Academic Search

The problem of reconstructing the duplication tree of a set of tandemly repeated sequences which are supposed to have arisen by unequal recombination, was first introduced by Fitch (1977), and has recently received a lot of attention. In this paper, we place ourselves in a distance framework and deal with the restricted problem of reconstructing single copy duplication trees. We

Olivier Elemento; Olivier Gascuel

2003-01-01

387

HRAS1 Variable Number of Tandem Repeats Polymorphism in Japanese Patients with Colorectal Adenoma and Cancer  

Microsoft Academic Search

The highly polymorphic HRAS1 variable number of tandem repeats (VNTR) has been described as an inherited predisposing factor in various human cancers. The aim of the present study was to evaluate the association between the presence of rare HRAS1 VNTR alleles and colorectal adenoma and cancer. A total of 165 Japanese patients underwent total colonoscopy with informed consent, and were

Masahiko Miura; Naoto Maeda; Yoshikazu Murawaki

388

Optimization of the absorption efficiency of an amorphous-silicon thin-film tandem solar cell  

E-print Network

Optimization of the absorption efficiency of an amorphous-silicon thin-film tandem solar cell to be made of hydrogenated amorphous-silicon alloys and the back reflector of bulk aluminum. The incidence-plasmon-polariton (SPP) waves guided by the semiconductor/metal interface [4]. Thin-film solar cells containing amorphous-silicon

389

Dearomatization strategy of ?-enamino ester: construction of indenoazepines via tandem Michael addition/polycyclization.  

PubMed

A dearomatization strategy of ?-enamino esters was developed to construct indenoazepine derivatives. The oxidative dearomatization was combined with a base-promoted tandem Michael addition/polycyclization and an acid-catalyzed aromatization. The nonaromatic structure of the Michael adducts might be essential to the realization of the 7-endo-dig cyclization. PMID:23795890

Yang, Min; Tang, Jie; Fan, Renhua

2013-07-01

390

Broadband Quantum Efficiency Enhancement in High Index Nanowires Resonators  

E-print Network

Light trapping in sub-wavelength semiconductor nanowires (NWs) offers a promising approach to simultaneously reducing material consumption and enhancing photovoltaic performance. Nevertheless, the absorption efficiency of a NW, defined by the ratio of optical absorption cross section to the NW diameter, lingers around 1 in existing NW photonic devices, and the absorption enhancement suffers from a narrow spectral width. Here, we show that the absorption efficiency can be significantly improved in NWs with higher refractive indices, by an experimental observation of up to 350% external quantum efficiency (EQE) in lead sulfide (PbS) NW resonators, a 3-fold increase compared to Si NWs. Furthermore, broadband absorption enhancement is achieved in single tapered NWs, where light of various wavelengths is absorbed at segments with different diameters analogous to a tandem solar cell. Overall, the single NW Schottky junction solar cells benefit from optical resonance, near bandgap open circuit voltage, and long mino...

Yang, Yiming; Hyatt, Steven; Yu, Dong

2015-01-01

391

EDITORIAL: Enhancing nanolithography Enhancing nanolithography  

NASA Astrophysics Data System (ADS)

Lithography was invented in late 18th century Bavaria by an ambitious young playwright named Alois Senefelder. Senefelder experimented with stone, wax, water and ink in the hope of finding a way of reproducing text so that he might financially gain from a wider distribution of his already successful scripts. His discovery not only facilitated the profitability of his plays, but also provided the world with an affordable printing press that would ultimately democratize the dissemination of art, knowledge and literature. Since Senefelder, experiments in lithography have continued with a range of innovations including the use of electron beams and UV that allow increasingly higher-resolution features [1, 2]. Applications for this have now breached the limits of paper printing into the realms of semiconductor and microelectronic mechanical systems technology. In this issue, researchers demonstrate a technique for fabricating periodic features in poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) [3]. Their method combines field enhancements from silica nanospheres with laser-interference lithography to provide a means of patterning a polymer that has the potential to open the market of low-end, high-volume microelectronics. Laser-interference lithography has already been used successfully in patterning. Researchers in Korea used laser-interference lithography to generate stamps for imprinting a two-dimensional photonic crystal structure into green light emitting diodes (LEDs) [4]. The imprinted patterns comprised depressions 100 nm deep and 180 nm wide with a periodicity of 295 nm. In comparison with unpatterned LEDs, the intensity of photoluminescence was enhanced by a factor of seven in the LEDs that had the photonic crystal structures imprinted in them. The potential of exploiting field enhancements around nanostructures for new technologies has also attracted a great deal of attention. Researchers in the USA and Australia have used the field enhancements around an array of nanorods to improve the operation of a Schottky diode device operating in reverse bias. The diode is used for gas sensing, an application that also benefits from the high surface to volume ratio of nanostructures for gas adsorption [5]. Enhancing the electric field is also hugely advantageous for Raman spectroscopy. The vibrational modes probed with Raman spectroscopy provide a useful, highly distinctive molecular signature but the signal is weak. An array of nanoneedles fabricated by researchers in China and Japan has demonstrated controllable and repeatable enhancements to Raman signals of 108 [6]. Researchers in the UK have demonstrated how the field enhancements resulting from the plasmonic properties of metal nanoparticles can be tuned to carefully manipulate their effect on the fluorescence intensity, lifetime and Raman signal from nearby fluorophores. They also successfully decoupled the effects on radiative and non-radiative decay and shed light on the hot spots present in surface-enhanced Raman spectroscopy measurements. Plasmonics has enormous potential in the field of optoelectronics. In recognition of the fertility of research in this field, Nanotechnology will publish a special issue on plasmonics in optoeletronics later this year. The work of Suman Das and colleagues in the USA and Germany reported in this issue combines both field enhancements and laser-interference lithography to impart a nanoporous structure to a polymer with high industrial potential. PEDOT-PSS has high conductivity and is also moderately transparent, making it eligible for transparent conductors in electroluminescent devices, conducting layers in capacitors, photovoltaic cells and sensors. It has also been considered recently for bioelectronic applications, in particular neuronal cell signalling and neural interfaces, as a result of its electronic and ionic conductivity. The researchers irradiated a monolayer of silica nanospheres on a film of PEDOT-PSS with interfering laser beams. The interference gave rise to a periodic line-like pattern in the i

Demming, Anna

2012-01-01

392

Structure of a Longitudinal Actin Dimer Assembled by Tandem W Domains – Implications for Actin Filament Nucleation  

PubMed Central

Actin filament nucleators initiate polymerization in cells in a regulated manner. A common architecture among these molecules consists of tandem W domains that recruit three to four actin subunits to form a polymerization nucleus. We describe a low-resolution crystal structure of an actin dimer assembled by tandem W domains, where the first W domain is crosslinked to Cys-374 of the actin subunit bound to it, whereas the last W domain is followed by the C-terminal pointed end-capping helix of T?4. While the arrangement of actin subunits in the dimer resembles that of a long-pitch helix of the actin filament, important differences are observed. These differences result from steric hindrance of the W domain with inter-subunit contacts in the actin filament. We also determined the structure of the first W domain of Vibrio parahaemolyticus VopL crosslinked to actin Cys-374, and show it to be nearly identical to non-crosslinked W-actin structures. This result validates the use of crosslinking as a tool for the study of actin nucleation complexes, whose natural tendency to polymerize interferes with most structural methods. Combined with a biochemical analysis of nucleation, the structures may explain why nucleators based on tandem W domains with short inter-W linkers have relatively weak activity, cannot stay bound to filaments after nucleation, and are unlikely to influence filament elongation. The findings may also explain why Nucleation Promoting Factors of the Arp2/3 complex, which are related to tandem W domain nucleators, are ejected from branch junctions after nucleation. We finally show that the simple addition of the C-terminal pointed end-capping helix of T?4 to tandem W domains can change their activity from actin filament nucleation to monomer sequestration. PMID:20804767

Rebowski, Grzegorz; Namgoong, Suk; Boczkowska, Malgorzata; Leavis, Paul C.; Navaza, Jorge; Dominguez, Roberto

2010-01-01

393

Randomized Trial of Oral Misoprostol Treatment for Cervical Ripening Before Tandem Application in Cervix Cancer  

SciTech Connect

Purpose: To investigate the efficacy of oral misoprostol administered to facilitate tandem application to the cervix as a part of brachytherapy in patients with cervical cancer. Methods and Materials: Eighty patients with cervical cancer who had been planned to undergo brachytherapy at Dr. Luetfi Kirdar Kartal Training and Research Hospital were evaluated in a double-blind, prospective, randomized trial. Patients were divided randomly into two groups of 40 patients. The first and second groups received 400 {mu}g of misoprostol orally and placebo, respectively, 3 h before tandem application. The two groups were compared in terms of age, diameter of tumor, parity, age at first intercourse, amount of bleeding and pain at first tandem application, length of endometrial cavity measured by hysterometer, and size of Hegar dilators used for cervical dilatation. Results: Of all cases, 63.6%, 16.3%, 10%, 6.3%, 2.5%, and 1.3% were Stage IIB, IIIB, IIIA, IVA, IIA and IIC, respectively. Mean ({+-}SD) age (range) was 49.3 {+-} 13.1 (25-83) years and 56.6 {+-} 13.2 (30-78) years in the study and control groups, respectively (p = 0.015). Age at first intercourse, diameter of tumor, parity, amount of bleeding at first tandem application, and length of endometrial cavity measured by hysterometer were not significantly different between the two groups. Pain score was significantly higher in the control group (p < 0.001). Application was significantly easier in the study group compared with controls (p < 0.001). Average size of initial Hegar dilators used for cervical dilatation was significantly higher in the study group compared with controls (p = 0.017). Conclusion: Administration of misoprostol 400 {mu}g orally for cervical ripening before tandem application facilitates the procedure, increases patient tolerability and comfort, and may decrease complication rates.

Cepni, Kimia; Gul, Sule [Department of Radiation Oncology, Ministry of Health, Dr. Lutfi Kirdar Kartal Training and Research Hospital, Istanbul (Turkey); Cepni, Ismail [Department of Obstetrics and Gynecology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Gueralp, Onur, E-mail: dronur@hotmail.com [Department of Obstetrics and Gynecology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Sal, Veysel [Department of Obstetrics and Gynecology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Mayadagli, Alpaslan [Department of Radiation Oncology, Ministry of Health, Dr. Lutfi Kirdar Kartal Training and Research Hospital, Istanbul (Turkey)

2011-11-01

394

Structure of a Longitudinal Actin Dimer Assembled by Tandem W Domains: Implications for Actin Filament Nucleation  

SciTech Connect

Actin filament nucleators initiate polymerization in cells in a regulated manner. A common architecture among these molecules consists of tandem WASP homology 2 domains (W domains) that recruit three to four actin subunits to form a polymerization nucleus. We describe a low-resolution crystal structure of an actin dimer assembled by tandem W domains, where the first W domain is cross-linked to Cys374 of the actin subunit bound to it, whereas the last W domain is followed by the C-terminal pointed end-capping helix of thymosin {beta}4. While the arrangement of actin subunits in the dimer resembles that of a long-pitch helix of the actin filament, important differences are observed. These differences result from steric hindrance of the W domain with intersubunit contacts in the actin filament. We also determined the structure of the first W domain of Vibrio parahaemolyticus VopL cross-linked to actin Cys374 and show it to be nearly identical with non-cross-linked W-Actin structures. This result validates the use of cross-linking as a tool for the study of actin nucleation complexes, whose natural tendency to polymerize interferes with most structural methods. Combined with a biochemical analysis of nucleation, the structures may explain why nucleators based on tandem W domains with short inter-W linkers have relatively weak activity, cannot stay bound to filaments after nucleation, and are unlikely to influence filament elongation. The findings may also explain why nucleation-promoting factors of the Arp2/3 complex, which are related to tandem-W-domain nucleators, are ejected from branch junctions after nucleation. We finally show that the simple addition of the C-terminal pointed end-capping helix of thymosin {beta}4 to tandem W domains can change their activity from actin filament nucleation to monomer sequestration.

Rebowski, Grzegorz; Namgoong, Suk; Boczkowska, Malgorzata; Leavis, Paul C.; Navaza, Jorge; Dominguez, Roberto (IBS) [IBS; (BBRI); (UPENN-MED)

2013-11-20

395

Secondary Chromosomal Attachment Site and Tandem Integration of the Mobilizable Salmonella Genomic Island 1  

PubMed Central

Background The Salmonella genomic island 1 is an integrative mobilizable element (IME) originally identified in epidemic multidrug-resistant Salmonella enterica serovar Typhimurium (S. Typhimurium) DT104. SGI1 contains a complex integron, which confers various multidrug resistance phenotypes due to its genetic plasticity. Previous studies have shown that SGI1 integrates site-specifically into the S. enterica, Escherichia coli, or Proteus mirabilis chromosome at the 3? end of thdF gene (attB site). Methodology/Principal Findings Here, we report the transfer of SGI1 to a ?thdF mutant of S. Typhimurium LT2. In the absence of thdF, the frequency of transconjugant formation was reduced by around thirty times of magnitude. Through DNA sequencing SGI1 was shown to integrate specifically into a secondary attachment site (2nd attB), which is located in the intergenic region between the chromosomal sodB and purR genes. At this 2nd attB site, we found that a significant fraction of SGI1 transconjugants (43% of wild type and 100% of ?thdF mutant) contained tandem SGI1 arrays. Moreover, in wild type S. Typhimurium LT2 transconjugants, SGI1 integrated into both attachment sites, i.e., thdF and sodB-purR. The formation of SGI1 tandem arrays occurred in both specific attB sites. There was heterogeneity in the size of the SGI1 tandem arrays detected in single transconjugant colonies. Some arrays consisted as far as six SGI1s arranged in tandem. These tandem arrays were shown to persist during serial passages with or without antibiotic selection pressure. Conclusions/Significance The ability of integration into two distinct chromosomal sites and tandem array formation of SGI1 could contribute to its spread and persistence. The existence of a secondary attachment site in the Salmonella chromosome has potential implications for the mobility of SGI1, which may integrate in other attachment sites of other bacterial pathogens that do not possess the 1st or 2nd specific SGI1 attB sites of Salmonella. PMID:18446190

Doublet, Benoît; Golding, George R.; Mulvey, Michael R.; Cloeckaert, Axel

2008-01-01

396

DETERMINATION OF PHTHALATES IN WATER AND SOIL BY TANDEM MASS SPECTROMETRY UNDER CHEMICAL IONIZATION CONDITIONS WITH ISOBUTANE AS REAGENT GAS  

EPA Science Inventory

Phthalate determination is important because phthalates often are major impurities in samples and can have significant health effects. Tandem mass spectrometry under chemical ionization mass spectrometry conditions with isobutane as the reagent gas was used to determine 11 phthal...

397

Small tandemly repeated DNA sequences of higher plants likely originate from a tRNA gene ancestor.  

PubMed Central

Several monomers (177 bp) of a tandemly arranged repetitive nuclear DNA sequence of Brassica oleracea have been cloned and sequenced. They share up to 95% homology between one another and up to 80% with other satellite DNA sequences of Cruciferae, suggesting a common ancestor. Both strands of these monomers show more than 50% homology with many tRNA genes; the best homologies have been obtained with Lys and His yeast mitochondrial tRNA genes (respectively 64% and 60%). These results suggest that small tandemly repeated DNA sequences of plants may have evolved from a tRNA gene ancestor. These tandem repeats have probably arisen via a process involving reverse transcription of polymerase III RNA intermediates, as is the case for interspersed DNA sequences of mammalians. A model is proposed to explain the formation of such small tandemly repeated DNA sequences. Images PMID:3774553

Benslimane, A A; Dron, M; Hartmann, C; Rode, A

1986-01-01

398

Asymmetric tandem reactions of N-sulfonylimines and ?,?-unsaturated aldehydes: an alternative reaction pathway to that of using saturated aldehydes.  

PubMed

An organocatalyzed asymmetric tandem reaction of cyclic N-sulfonylimines and ?,?-unsaturated aldehydes was developed. These substrates follow an alternative reaction pathway to that of reactions involving saturated aldehydes, affording similar piperidine derivatives. PMID:25514188

An, Qianjin; Li, Jing; Shen, Jiefeng; Butt, Nicholas; Liu, Delong; Liu, Yangang; Zhang, Wanbin

2015-01-18

399

B(C6F5)3-promoted tandem silylation and intramolecular hydrosilylation: diastereoselective synthesis of oxasilinanes and oxasilepanes  

PubMed Central

B(C6F5)3 promotes regio- and stereoselective cyclizations of unsaturated alkoxysilanes to generate oxasilinanes and oxasilepanes. The same products are available directly from alkenols via tandem silylation and hydrosilylation. PMID:20919715

Shchepin, Roman; Xu, Chunping; Dussault, Patrick

2010-01-01

400

Selective route to 2-propenyl aryls directly from wood by a tandem organosolv and palladium-catalysed transfer hydrogenolysis.  

PubMed

A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23% yield (92% theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49% yield (92% theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents. PMID:24910404

Galkin, Maxim V; Samec, Joseph S M

2014-08-01

401

Two-dimensional cascade test of a highly loaded, low-solidity, tandem airfoil turbine rotor blade  

NASA Technical Reports Server (NTRS)

A tip region section of a low-solidity tandem airfoil blade for a turbine rotor was tested in a two-dimensional cascade tunnel at solidities of 0.736 and 0.912. Blade surface static pressures and blade exit total and static pressure and flow angle were surveyed. Blade surface velocities, wake shapes, and kinetic energy losses were analyzed and compared with values for 1.852 solidity tandem airfoil blading.

Kline, J. F.; Stabe, R. G.

1973-01-01

402

Irradiation of monolithic InP\\/Ga0.47In0.53As tandem solar cells  

Microsoft Academic Search

Prototype three-terminal, two-junction, monolithic InP\\/Ga0.47 In0.53As tandem solar cells were grown by the National Renewable Energy Laboratory (NREL) using metal-organic chemical vapor deposition (MOCVD). The tandem cells have been irradiated at room temperature with incremental fluences of 1-MeV electrons. One sun, AM0, 25°C I-V measurements and deep level transient spectroscopy (DLTS) measurements are reported for each fluence step. The results

R. J. Walters; G. J. Shaw; G. P. Summers; M. W. Wanlass; J. S. Ward

1992-01-01

403

Monolithic, series-connected InP\\/Ga0.47In0.53As tandem solar cells  

Microsoft Academic Search

The status of monolithic, series-connected InP\\/Ga0.47In 0.53As tandem solar cells is presented. Large-area, 2-terminal tandem cells designed for 1-sun applications in space are reported for the first time. AMO efficiencies as high as 20.1% at 25°C have been measured for cells with an area of 1.00 cm2. Areas for further improvement are discussed

M. W. Wanlass; J. S. Ward; K. A. Emery; T. J. Coutts

1993-01-01

404

GaInP\\/GaAs\\/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators  

Microsoft Academic Search

We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current

M. W. Wanlass; S. P. Ahrenkiel; D. S. Albin; J. J. Carapella; A. Duda; K. Emery; J. F. Geisz; K. Jones; Sarah Kurtz; T. Moriarty; M. J. Romero

2005-01-01

405

Investigation of High-Efficiency InGaP\\/GaAs Tandem Solar Cells under Concentration Operation  

Microsoft Academic Search

The photovoltaic properties of InGaP\\/GaAs tandem solar cells under concentration have been investigated for concentration application. A high efficiency of 31.2% has been obtained for the InGaP\\/GaAs tandem solar cell under 5.1 suns of AM1.5 illumination. However, as the light intensity further increases, the efficiency is limited due to the reduction in the fill factor. The results show that not

Mingju Yang; Tatsuya Takamoto; Eiji Ikeda; Hiroshi Kurita; Masafumi Yamaguchi

1998-01-01

406

High-efficiency orange and tandem white organic light-emitting diodes using phosphorescent dyes with horizontally oriented emitting dipoles.  

PubMed

Tandem white organic light-emitting diodes (WOLEDs) using horizontally oriented phosphorescent dyes in an exciplex-forming co-host are presented, along with an orange OLED. A high external quantum efficiency of 32% is achieved for the orange OLED at 1000 cd m(-2) and the tandem WOLEDs exhibit a high maximum EQE of 54.3% (PE of 63 lm W(-1)). PMID:24923483

Lee, Sunghun; Shin, Hyun; Kim, Jang-Joo

2014-09-01

407

Pyramidal surface textures for light trapping and antireflection in perovskite-on-silicon tandem solar cells.  

PubMed

Perovskite-on-silicon tandem solar cells show potential to reach > 30% conversion efficiency, but require careful optical control. We introduce here an effective light-management scheme based on the established pyramidal texturing of crystalline silicon cells. Calculations show that conformal deposition of a thin film perovskite solar cell directly onto the textured front surface of a high efficiency silicon cell can yield front surface reflection losses as low as 0.52mA/cm2. Combining this with a wavelength-selective intermediate reflector between the cells additionally provides effective light-trapping in the high-bandgap top cell, resulting in calculated absolute efficiency gains of 2 - 4%. This approach provides a practical and effective method to adapt existing high efficiency silicon cell designs for use in tandem cells, with conversion efficiencies approaching 35%. PMID:25607299

Schneider, Bennett W; Lal, Niraj N; Baker-Finch, Simeon; White, Thomas P

2014-10-20

408

Structure and Notch Receptor Binding of the Tandem WWE Domain of Deltex  

SciTech Connect

Deltex is a cytosolic effector of Notch signaling thought to bind through its N-terminal domain to the Notch receptor. Here we report the structure of the Drosophila Deltex N-terminal domain, which contains two tandem WWE sequence repeats. The WWE repeats, which adopt a novel fold, are related by an approximate two-fold axis of rotation. Although the WWE repeats are structurally distinct, they interact extensively and form a deep cleft at their junction that appears well suited for ligand binding. The two repeats are thermodynamically coupled; this coupling is mediated in part by a conserved segment that is immediately C-terminal to the second WWE domain. We demonstrate that although the Deltex WWE tandem is monomeric in solution, it forms a heterodimer with the ankyrin domain of the Notch receptor. These results provide structural and functional insight into how Deltex modulates Notch signaling, and how WWE modules recognize targets for ubiquitination.

Zweifel,M.; Leahy, D.; Barrick, D.

2005-01-01

409

Lightweight concentrator module with 30 percent AM0 efficient GaAs/GaSb tandem cells  

NASA Technical Reports Server (NTRS)

A concept is presented for an aerospace concentrator module with lightweight domed lenses and 30 percent AM0 efficient GaAs/GaSb tandem solar cell circuits. The performance of transparent GaAs cells is reviewed. NASA's high-altitude jet flight calibration data for recent GaSb cells assembled with bulk GaAs filters are reported, along with subsequent Boeing and NASA measurements of GaSb I-V performance at various light levels and temperatures. The expected performance of a basic two-terminal tandem concentrator circuit with three-to-one voltage matching is discussed. All of the necessary components being developed to assemble complete flight test coupons are shown. Straightforward interconnect and assembly techniques yield voltage matched circuits with near-optimum performance over a wide temperature range.

Avery, J. E.; Fraas, L. M.; Sundaram, V. S.; Mansoori, N.; Yerkes, J. W.; Brinker, D. J.; Curtis, H. B.; O'Neill, M. J.

1990-01-01

410

Ligand binding and gene control characteristics of tandem riboswitches in Bacillus anthracis.  

PubMed

Most riboswitches are composed of a single metabolite-binding aptamer and a single expression platform that function together to regulate genes in response to changing metabolite concentrations. In rare instances, two aptamers or sometimes two complete riboswitches reside adjacent to each other in untranslated regions (UTRs) of mRNAs. We have examined an example of a tandem riboswitch in the Gram-positive bacterium Bacillus anthracis that includes two complete riboswitches for thiamine pyrophosphate (TPP). Unlike other complex riboswitch systems described recently, tandem TPP riboswitches do not exhibit cooperative ligand binding and do not detect two different types of metabolites. In contrast, both riboswitches respond independently to TPP and are predicted to function in concert to mimic the more "digital" gene control outcome observed when two aptamers bind ligands cooperatively. Our findings further demonstrate that simple gene control elements made only of RNA can be assembled in different architectures to yield more complex gene control outcomes. PMID:17307816

Welz, Rüdiger; Breaker, Ronald R

2007-04-01

411

Organic-inorganic hybrid tandem multijunction photovoltaics with extended spectral response  

NASA Astrophysics Data System (ADS)

We demonstrate series-connected hybrid tandem multijunction photovoltaics by combining hydrogenated amorphous silicon (a-Si:H) and polymer-based organic photovoltaics (OPVs). To utilize the wide solar spectrum with cost-effective processes, we employed a solution-processed low band gap OPV subcell onto the a-Si:H subcell. The interfacial contact between the subcells strongly affects the photovoltaic performance of the tandem cells. By using MoO3 as an efficient hole transporting intermediate layer instead of the conventional conducting polymer, we obtained power conversion efficiency of 1.84% and open-circuit voltage (VOC) of 1.50 V which corresponds closely to the sum of VOCs of the subcells.

Kim, Taehee; Jeon, Jun Hong; Han, Seunghee; Lee, Doh-Kwon; Kim, Honggon; Lee, Wonmok; Kim, Kyungkon

2011-05-01

412

Detection and reconstruction of tandemly organized de novo copy number variations  

PubMed Central

Background The characterization of structural variations (SV) such as insertions, deletions and copy number variations is a critical step in the process of understanding the full genetic architecture of organisms. Copy number variations (CNV) have attracted much recent attention due to their effects on gene expression and disease status. Results In this paper, we present a method that utilizes next-generation sequencing technologies (NGS), in order to both detect and reconstruct CNVs. We focus on a special type of CNV, namely tandemly organized de novo CNVs, which have been shown to occur with high frequency in the mouse genome. Conclusions We apply our method to CNV regions randomly inserted into the reference mouse genome and show that our method achieves good performance for both detection and reconstruction of tandemly organized de novo CNVs. PMID:21172047

2010-01-01

413

Flexible organic tandem solar modules: a story of up-scaling  

NASA Astrophysics Data System (ADS)

The competition in the field of solar energy between Organic Photovoltaics (OPVs) and several Inorganic Photovoltaic technologies is continuously increasing to reach the ultimate purpose of energy supply from inexpensive and easily manufactured solar cell units. Solution-processed printing techniques on flexible substrates attach a tremendous opportunity to the OPVs for the accomplishment of low-cost and large area applications. Furthermore, tandem architectures came to boost up even more OPVs by increasing the photon-harvesting properties of the device. In this work, we demonstrate the road of realizing flexible organic tandem solar modules constructed by a fully roll-to-roll compatible processing. The modules exhibit an efficiency of 5.4% with geometrical fill factors beyond 80% and minimized interconnection-resistance losses. The processing involves low temperature (<70 °C), coating methods compatible with slot die coating and high speed and precision laser patterning.

Spyropoulos, George D.; Kubis, Peter; Li, Ning; Lucera, Luca; Salvador, Michael; Baran, Derya; Machui, Florian; Ameri, Tayebeh; Voigt, Monika M.; Brabec, Christoph J.

2014-10-01

414

Palladium(II)-Catalyzed Intramolecular Tandem Aminoalkylation via Divergent C(sp(3))-H Functionalization.  

PubMed

We have developed a Pd(II)-catalyzed oxidative tandem aminoalkylation via divergent C(sp(3))-H functionalization, affording three- and five-membered-ring fused indolines in good yields under two optimized conditions, respectively. The mechanism studies have indicated that the benzylic C-H cleavage involved in the former transformation is the rate-determining step, while the cleavage of amide ?-C-H in the latter is not. This is the first example of a Pd-catalyzed tandem reaction involving C(sp(3))-H activation without the employment of prefunctionalized reagents (e.g., halogenated and boron reagents) and directing groups, representing a green and economic protocol for the construction of N-containing heterocycles. PMID:25541675

Du, Wei; Gu, Qiangshuai; Li, Zhongliang; Yang, Dan

2015-01-28

415

Tandem Mirror Experiment Upgrade (TMX-U) overview-recent events  

SciTech Connect

Since its construction and commissioning was completed in the winter of 1981, the Tandem Mirror Experiment Upgrade (TMX-U) has been conducting tandem mirror thermal barrier experiments. The work, following the fall of 1983 when strong plugging with thermal barriers was achieved, has been directed toward controlling radial transport and forming thermal barriers with high density and Beta. This paper describes the overall engineering component of these efforts. Major changes to the machine have included vacuum improvements, changes to the Electron and Ion Cyclotron Resonance Heating systems (ECRH and ICRH), and the installation of a Plasma Potential Control system (PPC) for radial transport reduction. TMX-U operates an extensive diagnostics system that acquires data from 21 types of diagnostic instruments with more than 600 channels, in addition to 246 machine parameters. The changes and additions will be presented. The closing section of this paper will describe the initial study work for a proposed TMX-U octupole configured machine.

Calderon, M.O.; Bell, H.H.

1985-11-14

416

Tandem injected relativistic heavy ion facility at Brookhaven: Present and future  

SciTech Connect

The Brookhaven Tandem Facility has been recently joined to the Alternating Gradient Synchrotron (AGS) by means of an approx. =680 meter long heavy ion transfer line. The design and construction of this line are described as well as the Tandem and AGS modifications which made it possible to initiate a relativistic heavy ion research program. Operational experience and performance during the first 14.6 GeV/amu /sup 16/O and /sup 28/Si runs are reviewed. At present the facility is capable of accelerating ions up to mass approx.32. Future developments are described which will lead to the acceleration of heavier ions up to gold, and hopefully to the construction of a relativistic heavy ion collider for the entire mass range at center of mass energies up to 250 GeV per nucleon pair.

Thieberger, P.; Barton, D.S.; Benjamin, J.; Chasman, C.; Foelsche, H.; Wegner, H.E.

1987-04-01

417

Non-Target Screening of Veterinary Drugs Using Tandem Mass Spectrometry on SmartMass  

NASA Astrophysics Data System (ADS)

Non-target screening of veterinary drugs using tandem mass spectrometric data was performed on the SmartMass platform. This newly developed software uses the characteristic fragmentation patterns (CFP) to identify chemicals, especially those containing particular substructures. A mixture of 17 sulfonamides was separated by ultra performance liquid chromatography (UPLC), and SmartMass was used to process the tandem mass spectrometry (MS/MS) data acquired on an Orbitrap mass spectrometer. The data were automatically extracted, and each sulfonamide was recognized and analyzed with a prebuilt analysis rule. By using this software, over 98 % of the false candidate structures were eliminated, and all the correct structures were found within the top 10 of the ranking lists. Furthermore, SmartMass could also be used to identify slightly modified contraband drugs and metabolites with simple prebuilt rules. [Figure not available: see fulltext.

Xia, Bing; Liu, Xin; Gu, Yu-Cheng; Zhang, Zhao-Hui; Wang, Hai-Yan; Ding, Li-Sheng; Zhou, Yan

2013-05-01

418

Tandem array of nanoelectronic readers embedded coplanar to a fluidic nanochannel for correlated single biopolymer analysis  

PubMed Central

We have developed a two-step electron-beam lithography process to fabricate a tandem array of three pairs of tip-like gold nanoelectronic detectors with electrode gap size as small as 9?nm, embedded in a coplanar fashion to 60?nm deep, 100?nm wide, and up to 150??m long nanochannels coupled to a world-micro-nanofluidic interface for easy sample introduction. Experimental tests with a sealed device using DNA-protein complexes demonstrate the coplanarity of the nanoelectrodes to the nanochannel surface. Further, this device could improve transverse current detection by correlated time-of-flight measurements of translocating samples, and serve as an autocalibrated velocimeter and nanoscale tandem Coulter counters for single molecule analysis of heterogeneous samples. PMID:24753731

Lesser-Rojas, Leonardo; Sriram, K. K.; Liao, Kuo-Tang; Lai, Shui-Chin; Kuo, Pai-Chia; Chu, Ming-Lee; Chou, Chia-Fu

2014-01-01

419

Monolithic InP/Ga0.47In0.53As tandem solar cells for space  

NASA Technical Reports Server (NTRS)

A review is provided of progress made in the development of InP/Ga(0.47)In(0.53)As monolithic tandem solar cells since the last SPRAT conference. Improved one-sun, three terminal tandem designs have resulted in Air Mass Zero (AM0) efficiencies as high as 23.9 pct. at 25 C. Additionally, high efficiency concentrator versions of the three terminal device were developed. The best concentrator tandem has a peak AM0 efficiency of 28.8 pct. under 40.3 suns at 25 C. For the concentrator tandems, the subcell performance parameter temperature coefficients are reported as a function of the concentration ratio. Results from a computer modeling study are presented which provide a clear direction for improving the efficiency of the concentrator tandem. The prospects for fabricating high efficiency, series connected (i.e., two terminal) InP/Ga(0.47)In(0.53)As monolithic tandem cells are also discussed.

Wanlass, M. W.; Ward, J. S.; Coutts, T. J.; Emery, K. A.; Gessert, T. A.; Osterwald, C. R.

1991-01-01

420

GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators  

SciTech Connect

We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM, {approx}1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resulting handle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24 cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.

Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, S.; Moriarty, T.; Romero, M. J.

2005-08-01

421

Determination of genotoxic phenylhydrazine agaritine in mushrooms using liquid chromatography–electrospray ionization tandem mass spectrometry  

Microsoft Academic Search

A new method with good sensitivity and specificity for detecting and quantifying genotoxic hydrazines, agaritine and 4-(hydroxymethyl)phenylhydrazine (HMPH), was developed using liquid chromatography–electrospray tandem mass spectrometry (MS). Synthetic agaritine and HMPH were structurally assigned by H-, C- and two-dimensional nuclear magnetic resonance (NMR) analysis (HMBC and HMQC), high-resolution fast-atom bombardment (HR-FAB) MS and time of flight (TOF) MS. The polar

Kazunari Kondo; Asako Watanabe; Yuko Iwanaga; Ikuro Abe; Hideya Tanaka; Megumi Hamano Nagaoka; Hiroshi Akiyama; Tamio Maitani

2006-01-01

422

Genetic individualization of Cannabis sativa by a short tandem repeat multiplex system  

Microsoft Academic Search

Cannabis sativa is the most frequently used of all illicit drugs in the USA. Cannabis has been used throughout history for its stems in the\\u000a production of hemp fiber, seed for oil and food, and buds and leaves as a psychoactive drug. Short tandem repeats (STRs) were\\u000a chosen as molecular markers owing to their distinct advantages over other genetic methods.

Maria A. Mendoza; DeEtta K. Mills; Hemant Lata; Suman Chandra; Mahmoud A. ElSohly; Jose R. Almirall

2009-01-01

423

Landscape of Standing Variation for Tandem Duplications in Drosophila yakuba and Drosophila simulans  

PubMed Central

We have used whole genome paired-end Illumina sequence data to identify tandem duplications in 20 isofemale lines of Drosophila yakuba and 20 isofemale lines of D. simulans and performed genome wide validation with PacBio long molecule sequencing. We identify 1,415 tandem duplications that are segregating in D. yakuba as well as 975 duplications in D. simulans, indicating greater variation in D. yakuba. Additionally, we observe high rates of secondary deletions at duplicated sites, with 8% of duplicated sites in D. simulans and 17% of sites in D. yakuba modified with deletions. These secondary deletions are consistent with the action of the large loop mismatch repair system acting to remove polymorphic tandem duplication, resulting in rapid dynamics of gain and loss in duplicated alleles and a richer substrate of genetic novelty than has been previously reported. Most duplications are present in only single strains, suggesting that deleterious impacts are common. Drosophila simulans shows larger numbers of whole gene duplications in comparison to larger proportions of gene fragments in D. yakuba. Drosophila simulans displays an excess of high-frequency variants on the X chromosome, consistent with adaptive evolution through duplications on the D. simulans X or demographic forces driving duplicates to high frequency. We identify 78 chimeric genes in D. yakuba and 38 chimeric genes in D. simulans, as well as 143 cases of recruited noncoding sequence in D. yakuba and 96 in D. simulans, in agreement with rates of chimeric gene origination in D. melanogaster. Together, these results suggest that tandem duplications often result in complex variation beyond whole gene duplications that offers a rich substrate of standing variation that is likely to contribute both to detrimental phenotypes and disease, as well as to adaptive evolutionary change. PMID:24710518

Rogers, Rebekah L.; Cridland, Julie M.; Shao, Ling; Hu, Tina T.; Andolfatto, Peter; Thornton, Kevin R.

2014-01-01

424

Liquid chromatography–tandem mass spectrometric assay for diclofenac and three primary metabolites in mouse plasma  

Microsoft Academic Search

The first liquid chromatography–tandem mass spectrometric assay for the simultaneous determination of diclofenac, 4?-hydroxy-diclofenac, 5-hydroxy-diclofenac and diclofenac-acyl-glucuronide in mouse plasma, using a simple sample pre-treatment procedure, was developed and validated. Analytes in plasma were stabilized using acetic acid and ascorbic acid. After addition of the internal standard D4-diclofenac to a 10?l sample volume and protein precipitation with acetonitrile, the supernatant

Rolf W. Sparidans; Jurjen S. Lagas; Afred H. Schinkel; Jan H. M. Schellens; Jos H. Beijnen

2008-01-01

425

A Tandem Duplication of Manganese Superoxide Dismutase in Nosema bombycis and Its Evolutionary Origins  

Microsoft Academic Search

Microsporidia are a group of obligate intracellular eukaryotic parasites with small genomes. They infect animals from a wide\\u000a variety of phyla, including humans. Two manganese superoxide dismutase (MnSOD) genes, designated NbMnSOD1 and NbMnSOD2, were found to be organized in a tandem array within the Nosema bombycis genome. The genes, both 678 bp in length, were found to be more similar to

Heng Xiang; Guoqing Pan; Charles R. Vossbrinck; Ruizhi Zhang; Jinshan Xu; Tian Li; Zeyang Zhou; Cheng Lu; Zhonghuai Xiang

2010-01-01

426

T cell epitope characterization in tandemly repetitive Trypanosoma cruzi B13 protein.  

PubMed

Proteins containing tandemly repetitive sequences are present in several immunodominant protein antigens in pathogenic protozoan parasites. The tandemly repetitive Trypanosoma cruzi B13 protein is recognized by IgG antibodies from 98% of Chagas' disease patients. Little is known about the molecular mechanisms that lead to the immunodominance of the repeated sequences, and there is limited information on T cell epitopes in such repetitive antigens. We finely characterized the T cell recognition of the tandemly repetitive, degenerate B13 protein by T cell lines, clones and PBMC from Chagas' disease cardiomyopathy (CCC), asymptomatic T. cruzi infected (ASY) and non-infected individuals (N). PBMC proliferative responses to recombinant B13 protein were restricted to individuals bearing HLA-DQA1*0501(DQ7), -DR1, and -DR2; B13 peptides bound to the same HLA molecules in binding assays. The HLA-DQ7-restricted minimal T cell epitope [FGQAAAG(D/E)KP] was identified with an overlapping combinatorial peptide library including all B13 sequence variants in T. cruzi Y strain B13 protein; the underlined small residues GQA were the major HLA contact residues. Among natural B13 15-mer variant peptides, molecular modeling showed that several variant positions were solvent (TCR)-exposed, and substitutions at exposed positions abolished recognition. While natural B13 variant peptide S15.9 seems to be the immunodominant epitope for Chagas' disease patients, S15.4 was preferentially recognized by CCC rather than ASY patients, which may be pathogenically relevant. This is the first thorough characterization of T cell epitopes of a tandemly repetitive protozoan antigen and may suggest a role for T cell help in the immunodominance of protozoan repetitive antigens. PMID:15951215

Abel, Lúcia C J; Iwai, Leo K; Viviani, Wladia; Bilate, Angelina M; Faé, Kellen C; Ferreira, Renata C; Goldberg, Anna C; Juliano, Luiz; Juliano, Maria A; Ianni, Bárbara; Mady, Charles; Gruber, Arthur; Hammer, Juergen; Sinigaglia, Francesco; Kalil, Jorge; Cunha-Neto, Edecio

2005-01-01

427

Proteome research based on modern liquid chromatography – tandem mass spectrometry: separation, identification and quantification  

Microsoft Academic Search

Summary.  Recent developments of new generations of mass spectrometers and improvements in the field of chromatography have revolutionized\\u000a protein analytics. Particularly the combination of liquid chromatography as a separation tool for proteins and peptides with\\u000a tandem mass spectrometry as an identification tool referred to as LC-MS\\/MS has generated a powerful and broadly used technique\\u000a in the field of proteomics. The resolution

T. Fröhlich; G. J. Arnold

2006-01-01

428

Tandem chromosome fusions in karyotypic evolution of Muntiacus : evidence from M. feae and M. gongshanensis  

Microsoft Academic Search

The muntjacs (Muntiacus, Cervidae) are famous for their rapid and radical karyotypic diversification via repeated tandem chromosome fusions, constituting\\u000a a paradigm for the studies of karyotypic evolution. Of the five muntjac species with defined karyotypes, three species (i.e.\\u000a Muntiacus reevesi, 2n = 46; M. m. vaginalis, 2n = 6\\/7; and M. crinifrons, 2n = 8\\/9) have so far been investigated

L. Huang; J. Wang; W. Nie; W. Su; F. Yang

2006-01-01

429

High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters  

DOEpatents

A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

Wanlass, Mark W. (Golden, CO)

2011-11-29

430

Dynamics of Tandem Repetitive Afa-Family Sequences in Triticeae, Wheat-Related Species  

Microsoft Academic Search

.   The Afa-family sequences in wheat-related species, Triticeae, are tandem repetitive sequences of 340 bp. All the analyzed\\u000a Triticeae species carried the sequences in their genomes, though the copy numbers varied about 100-fold among the species.\\u000a The nucleotide fragments amplified by PCR were cloned and sequenced, and their behavior in the evolution of Triticeae was\\u000a analyzed by the neighbor-joining (NJ)

Kiyotaka Nagaki; Hisashi Tsujimoto; Tetsuo Sasakuma

1998-01-01

431

Genetics and Genomics of Core Short Tandem Repeat Loci Used in Human Identity Testing  

Microsoft Academic Search

ABSTRACT: Over the past decade, the human identity testing community has settled on a set of core short tandem repeat (STR) loci that are widely used for DNA typing applications. A variety of commercial,kits enable robust amplification of these core STR loci. A brief history is presented regarding,the selection of core autosomal,and Y-chromosomal,STR markers. The physical location of each STR

John M. Butler

2006-01-01

432

Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments  

SciTech Connect

We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented.

Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

1986-08-29

433

Analysis of selected anticonvulsants by high performance liquid chromatography-tandem mass spectrometry.  

PubMed

A method for the analysis of the basic antiepileptic compounds felbamate, lamotrigine, carbamazepine, carbamazepine-10,11-epoxide, gabapentin, pregabalin, levetiracetam, and oxcarbazepine monohydroxy derivative (oxcarb MHD) in human plasma is described. This protocol incorporates a simplified sample preparation step followed by quantitative high performance chromatography-tandem mass spectrometry detection of commonly prescribed and monitored anticonvulsant drugs. Since polytherapy is common in epilepsy patients, use of a multiconstituent assay can improve laboratory efficiency and reduce required analytical time. PMID:22767120

Collins, Jennifer A; Janis, Gregory C

2012-01-01

434

High-efficiency, monolithic, multi-bandgap, tandem, photovoltaic energy converters  

DOEpatents

A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

Wanlass, Mark W

2014-05-27

435

Drug Screening of Preserved Oral Fluid by Liquid Chromatography-Tandem Mass Spectrometry  

Microsoft Academic Search

Background: Oral fluid is an alternative matrix with potential applications in road-side drug screening, work-place testing, drug treatment programs, and epi- demiological surveys. Development of methods for ex- tensive drug screening in oral fluid is warranted. Methods: We developed a liquid chromatography- tandem mass spectrometry (LC-MS\\/MS) method for drug screening of preserved oral fluid collected with the Intercept® collection device.

Elisabeth Leere Øiestad; Unni Johansen; Asbjorg Solberg Christophersen

436

Analysis of nine short tandem repeat (STR) loci in the Slovenian population.  

PubMed

A polymerase chain reaction (PCR)-based short tandem repeat (STR) system consisting of nine loci has recently been introduced in Slovenia for use in routine forensic identity testing. Fluorescently labelled PCR products were analysed using an ABI PRISM 310 Genetic Analyzer. The STR loci analysed exhibit between 6 and 14 observed alleles per locus and have a combined matching probability of 2.3 x 10(-10). PMID:9728751

Zupanic, I; Balazic, J; Komel, R

1998-01-01

437

Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen  

SciTech Connect

This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H/sub 2/SO/sub 4/-H/sub 2/O system. (MOW)

Werner, R.W. (ed.)

1982-11-01

438

Trifluoroacetic anhydride promoted tandem conjugate addition of boronic acids/acetal ring opening.  

PubMed

A new stereoselective tandem reaction consisting of the metal-free conjugate addition of boronic acids followed by an intramolecular ring opening of a cyclic acetal has been disclosed. Optically pure polysubstituted tetrahydropyrans have been synthesized diastereoselectively by this new reaction. Two new C-C bonds and up to three stereocenters are formed in a single step, allowing the generation of quaternary stereocenters. PMID:22339156

Roscales, Silvia; Csáky, Aurelio G

2012-03-01

439

Autoregulation of the Rsc4 Tandem Bromodomain by Gcn5 Acetylation  

Microsoft Academic Search

SUMMARY An important issue for chromatin remodeling complexes is how their bromodomains recog- nize particular acetylated lysine residues in his- tones. The Rsc4 subunit of the yeast remodeler RSC contains an essential tandem bromo- domain (TBD) that binds acetylated K14 of his- tone H3 (H3K14ac). We report a series of crystal structures that reveal a compact TBD that binds H3K14ac

Andrew P. VanDemark; Margaret M. Kasten; Elliott Ferris; Annie Heroux; Christopher P. Hill; Bradley R. Cairns

2007-01-01

440

High-speed submerged and surface piercing cavitating hydrofoils, including tandem case  

Microsoft Academic Search

The iterative method that is originally developed before both for two- and three-dimensional single cavitating hydrofoils moving with a constant speed under free surface is applied to the case of high-speed (Froude number up to 6.5) and some figures are given. The method is also extended to include the surface piercing hydrofoils (vertical struts) and the case of tandem hydrofoils

Sakir Bal

2007-01-01

441

Of mice and men: fuzzy tandem repeats and divergent p53 transcriptional repertoires.  

PubMed

The clinical importance of tumor suppressor p53 makes it one of the most studied transcription factors. A comparison of mammalian p53 transcriptional repertoires may help identify fundamental principles in genome evolution and better understand cancer processes. Here we summarize mechanisms underlying the divergence of mammalian p53 transcriptional repertoires, with an emphasis on the rapid evolution of fuzzy tandem repeats containing p53 response elements. PMID:23412358

Morin, Aurélie; Bardot, Boris; Simeonova, Iva; Lejour, Vincent; Bouarich-Bourimi, Rachida; Toledo, Franck

2013-01-01

442

Structural Characterization of Flavonols and Flavanones in Nanogram Quantities by API-ionspray Tandem Mass Spectrometry  

Microsoft Academic Search

API-ionspray MS and tandem MS\\/MS techniques were utilized to elucidate the structures of ten flavonoids consisting of five flavonols-morin, and one O-methyl and three acetyl derivatives, and five flavanones-desmethoxymatteucinol, and one acetyl and three O-methyl analogs. Morin and desmethoxymatteucinol were isolated and identified previously from the barks of Vanieria cochinchinesis Lour. (Moraceae) and the flowers of Eugenia javanica Lam. (Myrtaceae),

Wu-Nan Wu; Chong Heng Huang

443

Expression of tandem invertase genes associated with sexual and vegetative growth cycles in potato  

Microsoft Academic Search

The organisation of two invertase genes (invGE and invGF) linked in direct tandem repeat within the potato genome is detailed. The genes exhibit a similar intron\\/exon structure which differs from previously described plant invertase genes; while intron locations are conserved between the genes, minor differences in exon length are seen. Both genes encode enzymes with putative extracellular location. Biochemical analysis

Anne L. Maddison; Peter E. Hedley; Rhonda C. Meyer; Naveed Aziz; Diane Davidson; Gordon C. Machray

1999-01-01

444

Evidence for Gene Conversion Between Tandemly Duplicated Cytoplasmic Actin Genes of Helicoverpa armigera (Lepidoptera:Noctuidae)  

Microsoft Academic Search

.   Tandemly duplicated actin genes have been isolated from a Helicoverpa armigera genomic library. Sequence comparisons with actin genes from other species suggest they encode cytoplasmic actins, being most\\u000a closely related to the Bombyx mori A3 actin gene. The duplicated H. armigera actin genes, termed A3a and A3b, share 98.3% nucleotide sequence identity over their entire putative coding region. Analysis

Ian J. Rourke; Peter D. East

1997-01-01

445

Multiresidue pesticide analysis of fruits by ultra-performance liquid chromatography tandem mass spectrometry  

Microsoft Academic Search

Ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS–MS) has been used for screening and quantification\\u000a of 32 pesticides and metabolites in two fruit matrices. The compounds investigated belonged to different chemical families\\u000a of insecticides, acaricides, fungicides, and herbicides; several metabolites were also included. Quantification was conducted\\u000a using matrix-matched standards calibration; response was a linear function of concentration in the

O. J. Pozo; M. Barreda; J. V. Sancho; F. Hernández; J. Ll. Lliberia; M. A. Cortés; B. Bagó

2007-01-01

446

A tandem of ?-tubulin genes preferentially expressed in radicular tissues from Zea mays  

Microsoft Academic Search

The identification of a cDNA (MR19) corresponding to a maize a-tubulin and homologous genomic clones (MG19\\/6 and MG19\\/14) is described. The cDNA has been isolated by differential screening of a cDNA maize root library. We have found two a-tubulin genes in a tandem arrangement in the genomic clones, separated by approximately 1.5 kbp. One of the genes (gene I) contains

Lluís Montoliu; Joan Rigau; Pere Puigdomènech

1990-01-01

447

STRAIN-BALANCED MULTI QUANTUM WELL SOLAR CELLS IN TANDEM STRUCTURES - FIRST EXPERIMENTAL RESULTS  

Microsoft Academic Search

The first results are presented of a monolithic, two terminal tandem solar cell incorporating strain- balanced multi-quantum-wells (MQW) into the second, GaAs based junction. This approach is expected to boost the photocurrent of the lower junction, allowing better spectral matching between top and bottom junctions without the need to thin the top cell. Measured efficiencies of experimental devices compare well

T. N. D. Tibbits; I. M. Ballard; K. W. J. Barnham; D. B. Bushnell; J. P. Connolly; G. Hill; J. S. Roberts; R. Airey; G. Smekens

448

Flight and Analytical Methods for Determining the Coupled Vibration Response of Tandem Helicopters  

NASA Technical Reports Server (NTRS)

Chapter one presents a discussion of flight-test and analysis methods for some selected helicopter vibration studies. The use of a mechanical shaker in flight to determine the structural response is reported. A method for the analytical determination of the natural coupled frequencies and mode shapes of vibrations in the vertical plane of tandem helicopters is presented in Chapter two. The coupled mode shapes and frequencies are then used to calculate the response of the helicopter to applied oscillating forces.

Yeates, John E , Jr; Brooks, George W; Houbolt, John C

1957-01-01

449

Large arrays of tandemly repeated DNA sequences in the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

We describe the characterization of tandemly repeated DNA sequences, which resemble the satellite DNA sequences of multicellular eucaryotes, in the unicellular green alga Chlamydomonas reinhardtii. Restriction enzymes that cleave C. reinhardtii DNA relatively frequently produce a number of high molecular weight DNA fragments in addition to the bulk of low molecular weight DNA fragments. pTANC 1.5 contains a 1.5 kb

Trudy Hails; Mark Jobling; Anil Day

1993-01-01

450

Quantification of rabeprazole in human plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

An analytical method based on liquid chromatography coupled with tandem mass spectrometry detection has been developed and validated for the determination of rabeprazole in human plasma using omeprazole as the internal standard. The analyte and internal standard was extracted with n-hexane–dichloromethane–isopropanol (20:10:1, v\\/v) and chromatographed isocratically on a Diamonsil C18 analytical column. Methanol was used as the mobile phase to

Yong Zhang; Xiaoyan Chen; Qi Gu; Dafang Zhong

2004-01-01

451

Direct current H- source for boron neutron capture therapy tandem acceleratora)  

NASA Astrophysics Data System (ADS)

One year experience of dc H- source operation at 2MeV tandem accelerator is described. The source delivers H- ion beams with controlled current in the range of 1-8mA and energy up to 25keV. Normalized 1rms emittance for 8mA beam is less than 0.2?mmmrad. Negative ions are produced on the cesiated anode of the Penning discharge, driven by plasma injection from the hollow cathode inserts.

Belchenko, Yu.; Sanin, A.; Gusev, I.; Khilchenko, A.; Kvashnin, A.; Rashchenko, V.; Savkin, V.; Zubarev, P.

2008-02-01

452

Available energy analysis of new tandem double-capillary tube refrigeration system for refrigerator-freezers  

Microsoft Academic Search

A new tandem double-capillary tube refrigeration system for refrigerator-freezers is proposed. A capillary tube was added\\u000a between the two evaporators in the fresh and frozen food storage chests to raise the evaporation temperature of the refrigerating\\u000a chamber, and reduce the heat exchange temperature difference and the available energy loss. Peng-Robinson (P-R) equation of\\u000a state was adopted to calculate the thermodynamic

He Maogang; Song Xinzhou; Zhang Ying; Zhang Jiantao

2008-01-01

453

Determination of Gastrodin and Ligustrazine Hydrochloride in Plasma and Brain Dialysate by LC–Tandem MS  

Microsoft Academic Search

A gradient liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of\\u000a gastrodin and ligustrazine hydrochloride in rat plasma and brain dialysates. Zolpidem was used as internal standard. For plasma\\u000a samples, solid-phase extraction was used and the brain dialysates were collected from freely moving rats using brain microdialysis.\\u000a Both were followed by HPLC separation and positive

Yun-Feng Lv; Xin Hu; Wei-Ming Cheng; Ying-Lan Nie; Kai-Shun Bi

2008-01-01

454

Variable-Number-of-Tandem-Repeats Analysis of Genetic Diversity in Pasteuria ramosa  

Microsoft Academic Search

Variable-number-of-tandem-repeats (VNTR) markers are increasingly being used in population genetic studies of bacteria. They\\u000a were recently developed for Pasteuria ramosa, an endobacterium that infects Daphnia species. In the present study, we genotyped P. ramosa in 18 infected hosts from the United Kingdom, Belgium, and two lakes in the United States using seven VNTR markers. Two Daphnia species were collected: D.

L. Mouton; D. Ebert

2008-01-01

455

Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors  

SciTech Connect

Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.

Krikorian, O.H.

1980-10-10

456

Fast quantitative detection of cocaine in beverages using nanoextractive electrospray ionization tandem mass spectrometry  

Microsoft Academic Search

Without any sample pretreatment, effervescent beverage fluids were manually sprayed into the primary ion plume created by\\u000a using a nanoelectrospray ionization source for direct ionization, and the analyte ions of interest were guided into an ion\\u000a trap mass spectrometer for tandem mass analysis. Functional ingredients (e.g., vitamins, taurine, and caffeine, etc.) and\\u000a spiked impurity (e.g., cocaine) in various beverages, such

Bin Hu; Xuejiao Peng; Shuiping Yang; Haiwei Gu; Huanwen Chen; Yanfu Huan; Tingting Zhang; Xiaolin Qiao

2010-01-01

457

The validation of short tandem repeat (STR) loci for use in forensic casework  

Microsoft Academic Search

A quadruplex reaction has been developed which amplifies the short tandem repeat (STR) loci HUMVWA31\\/A, HUMTHO1, HUMF13A1 and HUMFES\\/FPS. Detection of the PCR products employs denaturing poly-acrylamide gels coupled with fluorescent-based technology. This system has been evaluated for use in routine forensic casework and has been shown to be both robust and reproducible. The quadruplex reaction is as sensitive as

J. E. Lygo; P. E. Johnson; D. J. Holdaway; S. Woodroffe; C. P. Kimpton; P. Gill; J. P. Whitaker; T. M. Clayton

1994-01-01

458

Tandem Duplication of D-Loop and Ribosomal RNA Sequences in Lizard Mitochondrial DNA  

Microsoft Academic Search

Some Cnemidophorus exsanguis have mitochondrial DNA's (mtDNA's) that are 22.2 kilobases (kb) in size, whereas most have mtDNA's of 17.4 kb. Restriction site mapping, DNA transfer hybridization experiments, and electron microscopy show that the size increment stems from the tandem duplication of a 4.8-kb region that includes regulatory sequences and transfer and ribosomal RNA genes. This observation is notable in

Craig Moritz; Wesley M. Brown

1986-01-01

459

Tandem Duplications in Animal Mitochondrial DNAs: Variation in Incidence and Gene Content among Lizards  

Microsoft Academic Search

Size, location, gene content, and incidence were determined for 10 lizard mitochondrial DNA duplications. These range from 0.8 to 8.0 kilobases (kb) and account for essentially all of the observed size variation (17-25 kb). Cleavage-site mapping and transfer-hybridization experiments indicate that each duplication is tandem and direct, includes at least one protein or rRNA gene, and is adjacent to or

Craig Moritz; Wesley M. Brown

1987-01-01

460

Comparison of radioimmunoassay and liquid chromatography tandem mass spectrometry for determination of juvenile hormone titers  

Microsoft Academic Search

This paper compares the results of juvenile hormone (JH) titer determinations in two insect species, Melanoplus sanguinipes, a migratory grasshopper, and Acyrthosiphon pisum, the pea aphid, using a chiral-specific JH radioimmunoassay (RIA) and liquid chromatography tandem mass spectrometry (LC-MS\\/MS), after extraction of JH with either hexane or isooctane–methanol.We compared results of JH titer determinations done on extracts of M. sanguinipes

Zhaorigetu Chen; Klaus D. Linse; Tina E. Taub-Montemayor; Mary Ann Rankin

2007-01-01

461

Development of micromorph tandem solar cells on flexible low-cost plastic substrates  

Microsoft Academic Search

We report on the development of fully flexible microcrystalline and micromorph tandem solar cells directly on low-cost substrates like poly-ethylen-terephtalate (PET) and poly-ethylen-naphtalate (PEN). The cells are deposited in nip or nip\\/nip configuration on the plastic substrate coated with a highly reflecting Ag–ZnO back contact. Light trapping is achieved by combining a periodically textured substrate and a diffusing ZnO front

F.-J. Haug; T. Söderström; M. Python; V. Terrazzoni-Daudrix; X. Niquille; C. Ballif

2009-01-01

462

Solution processed, white emitting tandem organic light-emitting diodes with inverted device architecture.  

PubMed

Fully solution processed monochromatic and white-light emitting tandem or multi-photon polymer OLEDs with an inverted device architecture have been realized by employing WO3 /PEDOT:PSS/ZnO/PEI charge carrier generation layers. The luminance of the sub-OLEDs adds up in the stacked device indicating multi-photon emission. The white OLEDs exhibit a CRI of 75. PMID:24899163

Höfle, Stefan; Schienle, Alexander; Bernhard, Christoph; Bruns, Michael; Lemmer, Uli; Colsmann, Alexander

2014-08-13

463