WorldWideScience

Sample records for highly active sers

  1. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

  2. {331}-Faceted trisoctahedral gold nanocrystals: synthesis, superior electrocatalytic performance and highly efficient SERS activity

    Science.gov (United States)

    Song, Yahui; Miao, Tingting; Zhang, Peina; Bi, Cuixia; Xia, Haibing; Wang, Dayang; Tao, Xutang

    2015-04-01

    We investigate the effect of gold (Au) seeds prepared in cetyltrimethylammonium chloride solution (CTAC-Au seeds) on the index facets of trisoctahedral gold nanocrystals (TOH Au NCs). We demonstrate that monodisperse {331}-faceted TOH Au NCs with controllable sizes (from 60 to 255 nm) can be successfully prepared in high yield by using 3.0 nm CTAC-Au seeds or as-prepared 70 nm TOH Au NCs as seeds. We find that the electrocatalytic performance on methanol oxidation and surface enhancement Raman spectroscopy (SERS) activity of {331}-faceted TOH Au NCs is size-dependent. In comparison with well-known nanoporous gold (0.088 mA cm-2), {331}-faceted TOH Au NCs with sizes of 110 nm exhibit fairly high catalytic activity (0.178 mA cm-2) on methanol oxidation (1.0 M) in alkaline media due to the presence of increasing density of atomic steps, ledges, and kinks on the NC surfaces. Their current density is reduced by less than 7% after 500 cycling tests. {331}-Faceted TOH Au NCs with sizes of 175 nm exhibit the highest SERS activity for 4-aminothiophenol (4-ATP) molecules. The enhancement factors of a1 modes of 4-ATP molecules can reach the order of 109 when the 4-ATP concentration is 3 × 10-6 M. Moreover, Raman signals (ag modes) of 4,4'-dimercaptoazobenzene (DMAB) molecules on TOH Au NCs are stronger than those on spherical Au NCs of comparable size due to the enhanced laser-induced transformation of 4-ATP molecules by high-index {331}-facets during SERS measurement. Furthermore, the SERS intensities of 4-methylbenzenethiol (4-MTP) molecules on TOH Au NCs are also higher than those on spherical Au NCs of comparable size due to sharp extremities.We investigate the effect of gold (Au) seeds prepared in cetyltrimethylammonium chloride solution (CTAC-Au seeds) on the index facets of trisoctahedral gold nanocrystals (TOH Au NCs). We demonstrate that monodisperse {331}-faceted TOH Au NCs with controllable sizes (from 60 to 255 nm) can be successfully prepared in high yield by

  3. Facile fabrication of silver nanoparticles with temperature-responsive sizes as highly active SERS substrates

    Science.gov (United States)

    Wu, Jing; Fang, Jinghuai; Cheng, Mingfei; Gong, Xiao

    2016-12-01

    In our work, large-scale silver NPs (nanoparticles) are successfully synthesized on zinc foils with controllable size by regulating the temperature of the displacement reaction. Our results show that when the temperature is 70 °C, the average size of silver NPs is approximately 88 nm in diameter, and they exhibit the strongest SERS activity. The gap between nanoparticles is simultaneously regulated as near as possible, which produces abundant "hot spots" and nanogaps. Crystal violet (CV) was used as probe molecules, and the SERS signals show that the values of relative standard deviation in the intensity of the main vibration modes are less than 10%, demonstrating excellent reproducibility of the silver NPs. Furthermore, the high surface-average enhancement factor of 3.86 × 107 is achieved even when the concentration of CV is 10-7 M, which is sufficient for single-molecule detection. We believe that this low cost and rapid route would get wide applications in chemical synthesis.

  4. Fabrication of highly active and cost effective SERS plasmonic substrates by electrophoretic deposition of gold nanoparticles on a DVD template

    Energy Technology Data Exchange (ETDEWEB)

    Leordean, Cosmin; Marta, Bogdan; Gabudean, Ana-Maria; Focsan, Monica; Botiz, Ioan; Astilean, Simion, E-mail: simion.astilean@phys.ubbcluj.ro

    2015-09-15

    Highlights: • Simple and cost effective electrophoretic method to fabricate plasmonic substrates. • SERS performance at three different excitation laser lines. • Promising applicability in SERS based biosensing. - Abstract: In this work we present a simple, rapid and cost effective method to fabricate highly active SERS substrates. This method consists in an electrophoretic deposition of gold nanoparticles on a metallic nanostructured template of a commercial digital versatile disk (DVD). The negatively charged gold nanoparticles self-assemble on the positively charged DVD metallic film connected to a positive terminal of a battery, due to the influence of the electric field. When gold nanoparticles self-assembled on DVD metallic film, a 10-fold additional enhancement of Raman signal was observed when compared with the case of GNPs self-assembled on a polycarbonate DVD substrate only. Finite-difference time-domain simulations demonstrated that the additional electromagnetic field arising in the hot-spots created between gold nanoparticles and DVD metallic film induces an additional enhancement of the Raman signal. SERS efficiency of the fabricated plasmonic substrate was successfully demonstrated through detection of para-aminothiophenol molecule with three different excitation laser lines (532, 633 and 785 nm). The enhancement factor was calculated to be 10{sup 6} and indicates that plasmonic substrates fabricated through this method could be a promising platform for future SERS based sensors.

  5. SERS-Active Nanoinjector for Intracellular Spectroscopy

    Science.gov (United States)

    Vitol, Elina; Orynbayeva, Zulfiya; Bouchard, Michael; Azizkhan-Clifford, Jane; Friedman, Gary; Gogotsi, Yury

    2009-03-01

    We developed a multifunctional nanopipette which allows simultaneous cell injection and intacellular surface-enhanced Raman spectroscopy (SERS) analysis. SERS spectra contain the characteristic frequencies of molecular bond vibrations. This is a unique method for studying cell biochemistry and physiology on a single organelle level. Unlike the fluorescence spectroscopy, it does not require any specific staining. The principle of SERS is based on very large electromagnetic field enhancement localized around a nano-rough metallic surface. Gold colloids are widely used SERS substrates. Previously, the colloidal nanoparticles were introduced into a cell by the mechanism of endocytosis. The disadvantage of this method is the uncontrollable aggregation and distribution of gold nanoparticles inside a cell which causes a significant uncertainty in the origin of the acquired data. At the same time, the nanoparticle uptake is irreversible. We present a SERS-active nanoinjector, coated with gold nanoparticles, which enables selective signal acquisition from any point-of-interest inside a cell. The nanoinjector provides a highly localized SERS signal with sub-nanometer resolution in real time.

  6. Fabrication of cube-like Fe3O4@SiO2@Ag nanocomposites with high SERS activity and their application in pesticide detection

    International Nuclear Information System (INIS)

    Li, Lei; Zhao, Aiwu; Wang, Dapeng; Guo, Hongyan; Sun, Henghui; He, Qinye

    2016-01-01

    The cube-like Fe 3 O 4 @SiO 2 @Ag (FSA) nanocomposites with great SERS activity have been successfully synthesized by a layer-by-layer procedure in this paper. The cube-like Fe 3 O 4 @SiO 2 core–shell structures were prepared via a new route and Ag nanoparticles were introduced onto their surface through a one-pot hydrothermal reaction. By controlling the reaction time, the coverage rate of Ag on the FSA surface could be tuned, and then a series of FSA composites were obtained. The SERS properties of these FSA composites were investigated using p-aminothiophenol (p-ATP) as the probe molecule. It was found that the FSA composites synthesized with a reaction time of 6 h showed the best SERS performance, and the detection limit for p-ATP could reach 1 × 10 −7 M. For practical application, the FSA composites were also used to detect thiram, one of the dithiocarbamate fungicides that has been widely used as a pesticide in agriculture. The detection limit is as low as 1 × 10 −6 M (0.24 ppm), lower than the maximal residue limit of 7 ppm in fruit prescribed by the US Environmental Protection Agency. The resulting substrate with high SERS activity, stability and strong magnetic responsivity makes the FSA composite a perfect choice for practical SERS detection applications.

  7. Development of SERS active fibre sensors

    International Nuclear Information System (INIS)

    Polwart, Ewan

    2002-01-01

    Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a (3-aminopropyl)trimethoxysilane-derivatised optical fibre. These sensors were used to obtain spectra with good signal to noise ratios from 4-(benzotriazol-5-ylazo)-3,5-dimethoxyphenylamine and crystal violet. Sensing of dyes in effluent was also investigated. The development of sensors for the measurement of pH, by treating the SERS-active fibre tip with pH sensitive dyes is also described. Spectral changes were observed with these sensors as a response to the pH. Partial least squares regression was used to produce linear calibration models for the pH range 5-11 from which it was possible to predict the pH with an accuracy of ∼0.2 pH units. Some of the limitations of these sensors were explored. The feasibility of using these sensors for measurement of oxygen and thiols, was investigated. The measurement of oxygen using methylene blue as a transducer was demonstrated. Two transduction methodologies--reactions with iron porphyrins and pyrrole-2,5-diones

  8. Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection

    Directory of Open Access Journals (Sweden)

    Pedro M. Fierro-Mercado

    2012-01-01

    Full Text Available We report on a novel and extremely low-cost surface-enhanced Raman spectroscopy (SERS substrate fabricated depositing gold nanoparticles on common lab filter paper using thermal inkjet technology. The paper-based substrate combines all advantages of other plasmonic structures fabricated by more elaborate techniques with the dynamic flexibility given by the inherent nature of the paper for an efficient sample collection, robustness, and stability. We describe the fabrication, characterization, and SERS activity of our substrate using 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and 1,3,5-trinitrobenzene as analytes. The paper-based SERS substrates presented a high sensitivity and excellent reproducibility for analytes employed, demonstrating a direct application in forensic science and homeland security.

  9. Electrostatic Assemblies of Well-Dispersed AgNPs on the Surface of Electrospun Nanofibers as Highly Active SERS Substrates for Wide-Range pH Sensing.

    Science.gov (United States)

    Yang, Tong; Ma, Jun; Zhen, Shu Jun; Huang, Cheng Zhi

    2016-06-15

    Surface-enhanced Raman scattering (SERS) has shown high promise in analysis and bioanalysis, wherein noble metal nanoparticles (NMNPs) such as silver nanoparticles were employed as substrates because of their strong localized surface plasmon resonance (LSPR) properties. However, SERS-based pH sensing was restricted because of the aggregation of NMNPs in acidic medium or biosamples with high ionic strength. Herein, by using the electrostatic interaction as a driving force, AgNPs are assembled on the surface of ethylene imine polymer (PEI)/poly(vinyl alcohol) (PVA) electrospun nanofibers, which are then applied as highly sensitive and reproducible SERS substrate with an enhancement factor (EF) of 10(7)-10(8). When p-aminothiophenol (p-ATP) is used as an indicator with its b2 mode, a good and wide linear response to pH ranging from 2.56 to 11.20 could be available, and the as-prepared nanocomposite fibers then could be fabricated as excellent pH sensors in complicated biological samples such as urine, considering that the pH of urine could reflect the acid-base status of a person. This work not only emerges a cost-effective, direct, and convenient approach to homogeneously decorate AgNPs on the surface of polymer nanofibers but also supplies a route for preparing other noble metal nanofibrous sensing membranes.

  10. Sonochemically synthesized Ag nanoparticles as a SERS active substrate and effect of surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Dar, Nitzan, E-mail: n58987012@mail.ncku.edu.tw [Department of Material Science and Engineering, National Cheng Kung University, Tainan 70101 Taiwan (China); Chen, Kuang-Yu [Department of Material Science and Engineering, National Cheng Kung University, Tainan 70101 Taiwan (China); Nien, Yung-Tang, E-mail: ytnien@nfu.edu.tw [Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 63201, Taiwan (China); Perkas, Nina [Institute of nanotechnology and advanced materials, Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002 (Israel); Gedanken, Aharon, E-mail: Aharon.Gedanken@biu.ac.il [Institute of nanotechnology and advanced materials, Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002 (Israel); Chen, In-Gann, E-mail: ingann@mail.ncku.edu.tw [Department of Material Science and Engineering, National Cheng Kung University, Tainan 70101 Taiwan (China)

    2015-03-15

    Highlights: • Solid state Ag SERS active substrates were sonochemically synthesized. • High intensity SERS spectra of both crystal violet and rhodamine 6G were observed. • We discovered that PVP aided synthesized substrates showed higher SERS intensity. - Abstract: Surface enhanced Raman scattering (SERS) enables the detection of substances at low concentrations using silver or gold nanostructure. The SERS technique has many applications, such as environmental detection and biosensing. Sonochemistry is an excellent and cheap deposition technique for coating substrates in a form of nanostructure at ambient temperature. It can also be utilized to prepare large SERS substrates. Here, we used the advantages of sonochemistry to deposit solid SERS substrates immobilized on GaN nanostructure. Morphology was studied by scanning electron microscopy. The elemental composition and the spatial distribution were examined by energy dispersive X-ray spectroscopy. The crystal structure and atomic presence was confirmed by X-ray diffraction. SERS substrates were examined with the analytes crystal violet (10{sup −5} M) and rhodamine 6G (10{sup −6} M), they showed prominent characteristic peaks. We discovered that the SERS intensity of poly-vinyl-pyrrolidinone aided sonochemical deposition of Ag nanoparticles was increased. The reason for the effect is morphological changes of the Ag nanoparticles. Smaller nanoparticles were fabricated, which increase their SERS intensity.

  11. Porous Au-Ag Nanospheres with High-Density and Highly Accessible Hotspots for SERS Analysis.

    Science.gov (United States)

    Liu, Kai; Bai, Yaocai; Zhang, Lei; Yang, Zhongbo; Fan, Qikui; Zheng, Haoquan; Yin, Yadong; Gao, Chuanbo

    2016-06-08

    Colloidal plasmonic metal nanoparticles have enabled surface-enhanced Raman scattering (SERS) for a variety of analytical applications. While great efforts have been made to create hotspots for amplifying Raman signals, it remains a great challenge to ensure their high density and accessibility for improved sensitivity of the analysis. Here we report a dealloying process for the fabrication of porous Au-Ag alloy nanoparticles containing abundant inherent hotspots, which were encased in ultrathin hollow silica shells so that the need of conventional organic capping ligands for stabilization is eliminated, producing colloidal plasmonic nanoparticles with clean surface and thus high accessibility of the hotspots. As a result, these novel nanostructures show excellent SERS activity with an enhancement factor of ∼1.3 × 10(7) on a single particle basis (off-resonant condition), promising high applicability in many SERS-based analytical and biomedical applications.

  12. Au coated PS nanopillars as a highly ordered and reproducible SERS substrate

    Science.gov (United States)

    Kim, Yong-Tae; Schilling, Joerg; Schweizer, Stefan L.; Sauer, Guido; Wehrspohn, Ralf B.

    2017-07-01

    Noble metal nanostructures with nanometer gap size provide strong surface-enhanced Raman scattering (SERS) which can be used to detect trace amounts of chemical and biological molecules. Although several approaches were reported to obtain active SERS substrates, it still remains a challenge to fabricate SERS substrates with high sensitivity and reproducibility using low-cost techniques. In this article, we report on the fabrication of Au sputtered PS nanopillars based on a template synthetic method as highly ordered and reproducible SERS substrates. The SERS substrates are fabricated by anodic aluminum oxide (AAO) template-assisted infiltration of polystyrene (PS) resulting in hemispherical structures, and a following Au sputtering process. The optimum gap size between adjacent PS nanopillars and thickness of the Au layers for high SERS sensitivity are investigated. Using the Au sputtered PS nanopillars as an active SERS substrate, the Raman signal of 4-methylbenzenethiol (4-MBT) with a concentration down to 10-9 M is identified with good signal reproducibility, showing great potential as promising tool for SERS-based detection.

  13. Fabrication of cube-like Fe{sub 3}O{sub 4}@SiO{sub 2}@Ag nanocomposites with high SERS activity and their application in pesticide detection

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lei; Zhao, Aiwu, E-mail: awzhao@iim.ac.cn; Wang, Dapeng; Guo, Hongyan; Sun, Henghui; He, Qinye [Chinese Academy of Sciences, Institute of Intelligent Machines (China)

    2016-07-15

    The cube-like Fe{sub 3}O{sub 4}@SiO{sub 2}@Ag (FSA) nanocomposites with great SERS activity have been successfully synthesized by a layer-by-layer procedure in this paper. The cube-like Fe{sub 3}O{sub 4}@SiO{sub 2} core–shell structures were prepared via a new route and Ag nanoparticles were introduced onto their surface through a one-pot hydrothermal reaction. By controlling the reaction time, the coverage rate of Ag on the FSA surface could be tuned, and then a series of FSA composites were obtained. The SERS properties of these FSA composites were investigated using p-aminothiophenol (p-ATP) as the probe molecule. It was found that the FSA composites synthesized with a reaction time of 6 h showed the best SERS performance, and the detection limit for p-ATP could reach 1 × 10{sup −7} M. For practical application, the FSA composites were also used to detect thiram, one of the dithiocarbamate fungicides that has been widely used as a pesticide in agriculture. The detection limit is as low as 1 × 10{sup −6} M (0.24 ppm), lower than the maximal residue limit of 7 ppm in fruit prescribed by the US Environmental Protection Agency. The resulting substrate with high SERS activity, stability and strong magnetic responsivity makes the FSA composite a perfect choice for practical SERS detection applications.

  14. Highly active surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles infiltrated into SiO{sub 2} inverse opals

    Energy Technology Data Exchange (ETDEWEB)

    Ankudze, Bright; Philip, Anish [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Pakkanen, Tuula T., E-mail: Tuula.Pakkanen@uef.fi [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Matikainen, Antti; Vahimaa, Pasi [Institute of Photonics, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland)

    2016-11-30

    Highlights: • SERS substrates prepared by infiltration of nanoparticles into SiO{sub 2} inverse opal. • The SERS substrate gives an enhancement factor of 10{sup 7} for 4-aminothiophenol. • The sensitivity of the substrate is mainly attributed to gold nanoparticle clusters. - Abstract: SiO{sub 2} inverse opal (IO) films with embedded gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) application are reported. SiO{sub 2} IO films were loaded with AuNPs by a simple infiltration in a single cycle to form Au-SiO{sub 2} IOs. The optical property and the morphology of the Au-SiO{sub 2} IO substrates were characterized; it was observed that they retained the Bragg diffraction of SiO{sub 2} IO and the localized surface plasmon resonance (LSPR) of AuNPs. The SERS property of the Au-SiO{sub 2} IO substrates were studied with methylene blue (MB) and 4-aminothiophenol (4-ATP). The SERS enhancement factors were 10{sup 7} and 10{sup 6} for 4-ATP and MB, respectively. A low detection limit of 10{sup −10} M for 4-ATP was also obtained with the Au-SiO{sub 2} IO substrate. A relative standard deviation of 18.5% for the Raman signals intensity at 1077 cm{sup −1} for 4-ATP shows that the Au-SiO{sub 2} IO substrates have good signal reproducibility. The results of this study indicate that the Au-SiO{sub 2} IO substrates can be used in sensing and SERS applications.

  15. Synthesis, characterization and SERS activity of biosynthesized silver nanoparticles

    Science.gov (United States)

    Bindhu, M. R.; Sathe, V.; Umadevi, M.

    2013-11-01

    Silver nanoparticles were rapidly synthesized using Moringa oleifera flower extract as the reducing agent shows surface plasmon resonance peak at 439 nm. The size and shape of the nanoparticles controlled by varying the concentration of M. oleifera flower extract in the reaction medium. The synthesized silver nanoparticles were well-dispersed spherical nanoparticles with the average size of 14 nm. The retinoic acid present in M. oleifera flower extract used as reducing agent and proteins was responsible for capping of the bioreduced silver nanoparticles. The obtained nanoparticle shows size-dependent SERS activity. The SERS spectrum indicates that the pyridine adsorbed on the silver surface in a stand-on orientation via its nitrogen lone pair electrons.

  16. Nanosphere Templating Through Controlled Evaporation: A High Throughput Method For Building SERS Substrates

    Science.gov (United States)

    Alexander, Kristen; Hampton, Meredith; Lopez, Rene; Desimone, Joseph

    2009-03-01

    When a pair of noble metal nanoparticles are brought close together, the plasmonic properties of the pair (known as a ``dimer'') give rise to intense electric field enhancements in the interstitial gap. These fields present a simple yet exquisitely sensitive system for performing single molecule surface-enhanced Raman spectroscopy (SM-SERS). Problems associated with current fabrication methods of SERS-active substrates include reproducibility issues, high cost of production and low throughput. In this study, we present a novel method for the high throughput fabrication of high quality SERS substrates. Using a polymer templating technique followed by the placement of thiolated nanoparticles through meniscus force deposition, we are able to fabricate large arrays of identical, uniformly spaced dimers in a quick, reproducible manner. Subsequent theoretical and experimental studies have confirmed the strong dependence of the SERS enhancement on both substrate geometry (e.g. dimer size, shape and gap size) and the polarization of the excitation source.

  17. Advanced Gas Sensors Using SERS-Activated Waveguides

    Science.gov (United States)

    Lascola, Robert; McWhorter, Scott; Murph, Simona Hunyadi

    2010-08-01

    This contribution describes progress towards the development and testing of a functionalized capillary that will provide detection of low-concentration gas-phase analytes through SERS. Measurement inside a waveguide allows interrogation of a large surface area, potentially overcoming the short distance dependence of the SERS effect. The possible use of Raman spectroscopy for gas detection is attractive for IR-inactive molecules or scenarios where infrared technology is inconvenient. However, the weakness of Raman scattering limits the use of the technique to situations where low detection limits are not required or large gas pressures are present. With surface-enhanced Raman spectroscopy (SERS), signal enhancements of 106 are often claimed, and higher values are seen in specific instances. However, most of the examples of SERS analysis are on liquid-phase samples, where the molecular density is high, usually combined with some sort of sample concentration at the surface. Neither of these factors is present in gas-phase samples. Because the laser is focused to a small point in the typical experimental setup, and the spatial extent of the effect above the surface is small (microns), the excitation volume is miniscule. Thus, exceptionally large enhancements are required to generate a signal comparable to that obtained by conventional Raman measurements. A reflective waveguide offers a way to increase the interaction volume of the laser with a SERS-modified surface. The use of a waveguide to enhance classical Raman measurements was recently demonstrated by S.M. Angel and coworkers, who obtained 12- to 30-fold sensitivity improvements for nonabsorbing gases (CO2, CH4) with a silvered capillary (no SERS enhancement). Shi et al.. demonstrated 10-to 100-fold enhancement of aqueous Rhodamine 6G in a capillary coated with silver nanoparticles. They observed enhancements of 10- to 100-fold compared to direct sampling, but this relied on a "double substrate", which required

  18. Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

    Directory of Open Access Journals (Sweden)

    Oana-M. Buja

    2017-01-01

    Full Text Available A microfluidic setup which enables on-line monitoring of residues of malachite green (MG using surface-enhanced Raman scattering (SERS is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

  19. Silver coated aluminium microrods as highly colloidal stable SERS platforms.

    Science.gov (United States)

    Pazos-Perez, Nicolas; Borke, Tina; Andreeva, Daria V; Alvarez-Puebla, Ramon A

    2011-08-01

    We report on the fabrication of a novel material with the ability to remain in solution even under the very demanding conditions required for structural and dynamic characterization of biomacromolecule assays. This stability is provided by the increase in surface area of a low density material (aluminium) natively coated with a very hydrophilic surface composed of aluminium oxide (Al(2)O(3)) and metallic silver nanoparticles. Additionally, due to the dense collection of active hot spots on their surface, this material offers higher levels of SERS intensity as compared with the same free and aggregated silver nanoparticles. This journal is © The Royal Society of Chemistry 2011

  20. Reduced graphene oxide wrapped Ag nanostructures for enhanced SERS activity

    Science.gov (United States)

    Nair, Anju K.; Kala, M. S.; Thomas, Sabu; Kalarikkal, Nandakumar

    2018-04-01

    Graphene - metal nanoparticle hybrids have received great attention due to their unique electronic properties, large specific surface area, very high conductivity and more charge transfer. Thus, it is extremely advantages to develop a simple and efficient process to disperse metal nanostructures over the surface of graphene sheets. Herein, we report a hydrothermal assisted strategy for developing reduced graphene oxide /Ag nanomorphotypes (cube, wire) for surface enhanced Raman scattering (SERS) applications, considering the advantages of synergistic effect of graphene and plasmonic properties of Ag nanomorphotypes.

  1. Synthesis of SERS active Au nanowires in different noncoordinating solvents

    Energy Technology Data Exchange (ETDEWEB)

    Hou Xiaomiao; Zhang Xiaoling, E-mail: zhangxl@bit.edu.cn [Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Department of Chemistry, School of Science (China); Fang Yan, E-mail: fangyan@mail.cnu.edu.cn [Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Capital Normal University (China); Chen Shutang; Li Na; Zhou Qi [Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Department of Chemistry, School of Science (China)

    2011-06-15

    Au nanowires with length up to micrometers were synthesized through a simple and one-pot solution growth method. HAuCl{sub 4} was reduced in a micellar structure formed by 1-octadecylamine and oleic acid in hexane, heptane, toluene and chloroform, respectively. As the non-polarity of noncoordinating solvents can affect the nucleation and growth rates of Au nanostructures, Au nanowires with different diameters could be obtained by changing the noncoordinating solvents in the synthetic process. The influences of the solvents on the morphology of Au nanowires were systematically studied. When using hexane as reaction solvent, the product turned to be high portion of Au nanowires with more uniform size than the others. Furthermore, surface-enhanced Raman scattering (SERS) spectrum of 2-thionaphthol was obtained on the Au nanowire-modified substrate, indicating that the as-synthesized Au nanowires have potential for highly sensitive optical detection application.

  2. Design of Hybrid Nanostructural Arrays to Manipulate SERS-Active Substrates by Nanosphere Lithography.

    Science.gov (United States)

    Zhao, Xiaoyu; Wen, Jiahong; Zhang, Mengning; Wang, Dunhui; Wang, Yaxin; Chen, Lei; Zhang, Yongjun; Yang, Jinghai; Du, Youwei

    2017-03-01

    An easy-handling and low-cost method is utilized to controllably fabricate nanopattern arrays as the surface-enhanced Raman scattering (SERS) active substrates with high density of SERS-active areas (hot spots). A hybrid silver array of nanocaps and nanotriangles are prepared by combining magnetron sputtering and plasma etching. By adjusting the etching time of polystyrene (PS) colloid spheres array in silver nanobowls, the morphology of the arrays can be easily manipulated to control the formation and distribution of hot spots. The experimental results show that the hybrid nanostructural arrays have large enhancement factor, which is estimated to be seven times larger than that in the array of nanocaps and three times larger than that in the array of nanorings and nanoparticles. According to the results of finite-difference time-domain simulation, the excellent SERS performance of this array is ascribed to the high density of hot spots and enhanced electromagnetic field.

  3. Combining surface enhanced Raman scattering (SERS) and high-performance thin-layer chromatography (HPTLC)

    Science.gov (United States)

    Koglin, E.

    A new method for preparing SERS active surfaces using silver colloidal spheres deposited on HPTLC plates, used for thin-layer chromatography, is discussed in detail. The sensitivity of these activated HPTLC plates is so high that in-situ vibrational investigations of chromatogram spots are possible at the nanogram level. The HPTLC/SERS spectra of purine, benzoic acid and 1-nitro-pyrene adsorbed on silver colloidal activated silica gel plates are measured in the nanogram region. In addition we also report in this paper on the results of a feasibility study performed to evaluate the analytical potential of micro-Raman spectroscopy (triple monochromator, multichannel detection system) in SERS/HPTLC spot characterization. It permits the acquisition of Raman spectra from HPTLC spots down to 1 μm in size or other forms of microsamples approaching the picogram level in mass.

  4. Laser ablation studies of Deposited Silver Colloids Active in SERS

    International Nuclear Information System (INIS)

    La Porte, R.T.; Moreno, D.S.; Striano, M.C.; Munnoz, M.M.; Garcia-Ramos, J.V.; Cortes, S.S.; Koudoumas, E.

    2002-01-01

    Laser ablation of deposited silver colloids, active in SERS, is carried out at three different laser wavelengths (KrF, XeCl and Nd:YAG at λ = 248, 308 and 532 nm respectively). Emission form excited neutral Ag and Na atoms, present in the ablation plume, is detected with spectral and temporal resolution. The expansion velocity of Ag in the plume is estimated in ∼1x104m s-1, Low-fluence laser ablation of the colloids yields ionized species that are analyzed by time-of-flight mass spectroscopy. Na+ and Agn+(n≤3) are observed. Composition of the mass spectra and widths of the mass peaks are found to be dependent on laser wavelength, suggesting that the dominant ablation mechanisms are different at the different wavelenghts.

  5. Sodium Chloride Crystal-Induced SERS Platform for Controlled Highly Sensitive Detection of Illicit Drugs.

    Science.gov (United States)

    Yu, Borong; Li, Pan; Zhou, Binbin; Tang, Xianghu; Li, Shaofei; Yang, Liangbao

    2018-04-03

    A sodium chloride crystal-driven spontaneous 'hot spot' structure was demonstrated as a SERS-active platform, to get reproducible SERS signals, and eliminate the need for mapping large areas, in comparison with solution phase testing. During the process of solvent evaporation, the crystals produced induced silver aggregates to assemble around themselves. The micro-scale crystals can also act as a template to obtain an optical position, such that the assembled hot area is conveniently located during SERS measurements. More importantly, the chloride ions added in colloids can also replace the citrate and on the surface of the silver sol, and further decrease the background interference. High quality SERS spectra from heroin, methamphetamine (MAMP), and cocaine have been obtained on the crystal-driven hot spot structure with high sensitivity and credible reproducibility. This approach can not only bring the nanoparticles to form plasmonic hot spots in a controlled way, and thus provide high sensitivity, but also potentially be explored as an active substrate for label-free detection of other illicit drugs or additives. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. SERS-active ZnO/Ag hybrid WGM microcavity for ultrasensitive dopamine detection

    Science.gov (United States)

    Lu, Junfeng; Xu, Chunxiang; Nan, Haiyan; Zhu, Qiuxiang; Qin, Feifei; Manohari, A. Gowri; Wei, Ming; Zhu, Zhu; Shi, Zengliang; Ni, Zhenhua

    2016-08-01

    Dopamine (DA) is a potential neuro modulator in the brain which influences a variety of motivated behaviors and plays a key role in life science. A hybrid ZnO/Ag microcavity based on Whispering Gallery Mode (WGM) effect has been developed for ultrasensitive detection of dopamine. Utilizing this effect of structural cavity mode, a Raman signal of R6G (5 × 10-3 M) detected by this designed surface-enhanced Raman spectroscopy (SERS)-active substrate was enhanced more than 10-fold compared with that of ZnO film/Ag substrate. Also, this hybrid microcavity substrate manifests high SERS sensitivity to rhodamine 6 G and detection limit as low as 10-12 M to DA. The Localized Surface Plasmons of Ag nanoparticles and WGM-enhanced light-matter interaction mainly contribute to the high SERS sensitivity and help to achieve a lower detection limit. This designed SERS-active substrate based on the WGM effect has the potential for detecting neurotransmitters in life science.

  7. Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon.

    Science.gov (United States)

    Bandarenka, Hanna V; Girel, Kseniya V; Zavatski, Sergey A; Panarin, Andrei; Terekhov, Sergei N

    2018-05-21

    The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs), and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.

  8. Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon

    Directory of Open Access Journals (Sweden)

    Hanna V. Bandarenka

    2018-05-01

    Full Text Available The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs, and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.

  9. Ser649 and Ser650 are the major determinants of protein kinase A-mediated activation of human hormone-sensitive lipase against lipid substrates

    DEFF Research Database (Denmark)

    Krintel, Christian; Osmark, Peter; Larsen, Martin Røssel

    2008-01-01

    Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from stored triacylglycerols. Its activity is regulated by reversible protein phosphorylation. In rat HSL Ser563, Ser659 and Ser660 have been shown to be phosphorylated by protein kinase A (PKA) in vitro as well...

  10. Structure-dependent SERS activity of plasmonic nanorattles with built-in electromagnetic hotspots.

    Science.gov (United States)

    Liu, Keng-Ku; Tadepalli, Sirimuvva; Wang, Zheyu; Jiang, Qisheng; Singamaneni, Srikanth

    2017-11-20

    Hollow plasmonic nanostructures with built-in and accessible electromagnetic hotspots such as nanorattles, obtained through a galvanic replacement reaction, have received wide attention in chemical and biological sensing and targeted drug delivery. In this study, we investigate the surface enhanced Raman scattering (SERS) activity of plasmonic nanorattles obtained through different degrees of galvanic replacement of Au@Ag nanocubes. We found that the SERS efficacy of the nanorattles is governed by the plasmon extinction intensity, localized surface plasmon resonance (LSPR) wavelength of the nanostructures with respect to the excitation source and intensity of the electromagnetic field at the hotspot, with the latter playing a determining role. Finite-difference time-domain (FDTD) simulations showed excellent agreement with the experimental findings that an optimal degree of galvanic replacement is critical for maximum SERS enhancement. The rational design and synthesis of the plasmonic nanorattles based on these findings can make these nanostructures highly attractive for SERS-based chemical and biological sensing and bioimaging.

  11. [Size dependent SERS activity of gold nanoparticles studied by 3D-FDTD simulation].

    Science.gov (United States)

    Li, Li-mei; Fang, Ping-ping; Yang, Zhi-lin; Huang, Wen-da; Wu, De-yin; Ren, Bin; Tian, Zhong-qun

    2009-05-01

    By synthesizing Au nanoparticles with the controllable size from about 16 to 160 nm and measuring their SERS activity, the authors found that Au nanoparticles film with a size in the range of 120-135 nm showed the highest SERS activity with the 632.8 nm excitation, which is different from previous experimental results and theoretical predictions. The three dimensional finite difference time domain (3D-FDTD)method was employed to simulate the size dependent SERS activity. At the 632.8 nm excitation, the particles with a size of 110 nm shows the highest enhancement under coupling condition and presents an enhancement as high as 10(9) at the hot site. If the enhancement is averaged over the whole surface, the enhancement can still be as high as 10(7), in good agreement with our experimental data. For Au nanoparticles with a larger size such as 220 nm, the multipolar effect leads to the appearance of the second maximum enhancement with the increase in particles size. The averaged enhancement for the excitation line of 325 nm is only 10(2).

  12. Development of chitosan-coated gold nanoflowers as SERS-active probes

    Science.gov (United States)

    Xu, Dan; Gu, Jiangjiang; Wang, Weina; Yu, Xuehai; Xi, Kai; Jia, Xudong

    2010-09-01

    Surface-enhanced Raman scattering (SERS) has been intensely researched for many years as a potential technique for highly sensitive detection. This work, through the reduction of HAuCl4 with pyrrole in aqueous solutions, investigated a facile one-pot synthesis of flower-like Au nanoparticles with rough surfaces. The formation process of the Au nanoflowers (AuNFs) was carefully studied, and a spontaneous assembly mechanism was proposed based on the time-course experimental results. The key synthesis strategy was to use pyrrole as a weak particle stabilizing and reducing agent to confine crystal growth in the limited ligand protection region. The nanometer-scale surface roughness of AuNFs provided several hot spots on a single particle, which significantly increased SERS enhancement. Good biocompatible stable Raman-active probes were synthesized by coating AuNFs with chitosan. The conservation of the SERS effects in living cells suggested that the chitosan-capped AuNFs could be suitable for highly sensitive detection and have potential for targeting of tumors in vivo.

  13. [Preparation of a kind of SERS-active substrates for spot fast analysis].

    Science.gov (United States)

    Ji, Nan; Li, Zhi-Shi; Zhao, Bing; Zou, Bo

    2013-02-01

    A kind of SERS-active substrates was prepared using chemical self-assembly method, aiming at spot fast analysis using portable Raman spectrometer. PDDA was first absorbed on the inner wall of vials, and then Ag colloids were assembled on the inner wall. UV-Vis spectra and Raman spectra of two kinds of blank vials were investigated and the transparent vials were thought to be better for SERS-vials. UV-Vis spectra were used to monitor the assembly process of Ag colloids. SERS activity of our substrates was characterized using p-ATP as probing molecules.

  14. A novel bifunctional Ni-doped TiO2 inverse opal with enhanced SERS performance and excellent photocatalytic activity

    Science.gov (United States)

    Li, Xuehong; Wu, Yun; Shen, Yuhua; Sun, Yan; Yang, Ying; Xie, Anjian

    2018-01-01

    Three-dimensional inverse opal photonic microarray (IOPM) structure exhibits good qualities in structural regularity and interconnectivity, such as high specific surface area, large pore volume, uniform pore size, and ordered periodic construction. Here, a novel nickel-doped titanium dioxide IOPM (Ni-TiO2 IOPM) was fabricated for the first time as a bifunctional material for the applications of surface-enhanced Raman scattering (SERS) substrate and photocatalyst. The Ni doping could change the defect concentration of the substrate to enhance the SERS effect, and could increase the light absorption of the substrate in visible region. The synergistic effect of Ni doping and the periodically ordered porous structure enhanced both SERS sensitivity and photocatalytic activity. As a SERS substrate, the Ni-TiO2 IOPM exhibited highly sensitive detection capability for 4-mercaptobenzoic acid (4-MBA) at a concentration as low as 1 × 10-11 M. Under simulated sunlight, about 95% of the methylene blue (MB) was degraded within 90 min when Ni-TiO2 IOPM was used as the photocatalytst. The Ni-TiO2 IOPM prepared in this work may be a promising bifunctional SERS substrate candidate for organic sewage detection and environment protection. In addition, the fabrication strategy can be extended to synthesize other nanomaterials with orderly and porous structure.

  15. Aluminum nanostructures with strong visible-range SERS activity for versatile micropatterning of molecular security labels.

    Science.gov (United States)

    Lay, Chee Leng; Koh, Charlynn Sher Lin; Wang, Jing; Lee, Yih Hong; Jiang, Ruibin; Yang, Yijie; Yang, Zhe; Phang, In Yee; Ling, Xing Yi

    2018-01-03

    The application of aluminum (Al)-based nanostructures for visible-range plasmonics, especially for surface-enhanced Raman scattering (SERS), currently suffers from inconsistent local electromagnetic field distributions and/or inhomogeneous distribution of probe molecules. Herein, we lithographically fabricate structurally uniform Al nanostructures which enable homogeneous adsorption of various probe molecules. Individual Al nanostructures exhibit strong local electromagnetic field enhancements, in turn leading to intense SERS activity. The average SERS enhancement factor (EF) for individual nanostructures exceeds 10 4 for non-resonant probe molecules in the visible spectrum. These Al nanostructures also retain more than 70% of their original SERS intensities after one-month storage, displaying superb stability under ambient conditions. We further achieve tunable polarization-dependent SERS responses using anisotropic Al nanostructures, facilitating the design of sophisticated SERS-based security labels. Our micron-sized security label comprises two-tier security features, including a machine-readable hybrid quick-response (QR) code overlaid with a set of ciphertexts. Our work demonstrates the versatility of Al-based structures in low-cost modern chemical nano-analytics and forgery protection.

  16. Trace determination of thiram using SERS-active hollow sea-urchin gold nanoparticles

    International Nuclear Information System (INIS)

    Zhang, Guanghui; Zhang, Chuankun; Ma, Yanan; Wang, Zheng; Wang, Shun; Xu, Chan; Wang, Dashuang

    2017-01-01

    Surface-enhanced Raman scattering (SERS) is greatly structure-dependent on the absorbed nanoparticles. Nanostructures with different novel morphologies show different Raman enhancement factor orders of magnitude. Herein, a unique nanostructure with fruitful SERS-active sites, composed of hollow interiors and thorns which named as hollow sea-urchin gold nanoparticles (HSU-GNPs), was synthesized by using a one-pot galvanic replacement method. And the corresponding morphologies and optical properties were characterized by TEM images and absorption spectra. Importantly, the synthetic parameters of HSU-GNPs were optimized to obtain a superior SERS performance by analyzing the formation mechanism and the SERS spectra of R6G-labeled HSU-GNPs which obtained at different concentrations of AgNO_3. Furthermore, the SERS-based application of HSU-GNPs was performed on the dose-response detection of thiram. The experimental result shows this detection strategy is available for thiram with decent sensitivity and reproducibility, which suggests that it is an excellent candidate for the detection of pesticides.

  17. Trace determination of thiram using SERS-active hollow sea-urchin gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guanghui; Zhang, Chuankun, E-mail: zhangchk-lx@huat.edu.cn; Ma, Yanan; Wang, Zheng; Wang, Shun; Xu, Chan; Wang, Dashuang [Hubei University of Automotive Technology, School of Science (China)

    2017-04-15

    Surface-enhanced Raman scattering (SERS) is greatly structure-dependent on the absorbed nanoparticles. Nanostructures with different novel morphologies show different Raman enhancement factor orders of magnitude. Herein, a unique nanostructure with fruitful SERS-active sites, composed of hollow interiors and thorns which named as hollow sea-urchin gold nanoparticles (HSU-GNPs), was synthesized by using a one-pot galvanic replacement method. And the corresponding morphologies and optical properties were characterized by TEM images and absorption spectra. Importantly, the synthetic parameters of HSU-GNPs were optimized to obtain a superior SERS performance by analyzing the formation mechanism and the SERS spectra of R6G-labeled HSU-GNPs which obtained at different concentrations of AgNO{sub 3}. Furthermore, the SERS-based application of HSU-GNPs was performed on the dose-response detection of thiram. The experimental result shows this detection strategy is available for thiram with decent sensitivity and reproducibility, which suggests that it is an excellent candidate for the detection of pesticides.

  18. Effect of Etching on the Optical, Morphological Properties of Ag Thin Films for SERS Active Substrates

    Directory of Open Access Journals (Sweden)

    Desapogu Rajesh

    2013-01-01

    Full Text Available Structural, optical, and morphological properties of Ag thin films before and after etching were investigated by using X-ray diffraction, UV-Vis spectrophotometer, and field emission scanning electron microscopy (FESEM. The HNO3 roughened Ag thin films exhibit excellent enhancement features and better stability than pure Ag thin films. Further, the Ag nanostructures are covered with Rhodamine 6G (Rh6G and then tested with surface enhanced raman spectroscopy (SERS for active substrates. Etched Ag films were found to exhibit a strong SERS effect and excellent thermal stability. Hence, the present method is found to be useful in the development of plasmon-based analytical devices, especially SERS-based biosensors.

  19. Fabrication of SERS Active Surface on Polyimide Sample by Excimer Laser Irradiation

    Directory of Open Access Journals (Sweden)

    T. Csizmadia

    2014-01-01

    Full Text Available A possible application of excimer laser irradiation for the preparation of surface enhanced Raman spectroscopy (SERS substrate is demonstrated. A polyimide foil of 125 μm thickness was irradiated by 240 pulses of focused ArF excimer laser beam (λ = 193 nm, FWHM = 20 ns. The applied fluence was varied between 40 and 80 mJ/cm2. After laser processing, the sample was coated with 40 nm silver by PLD in order to create a conducting layer required for the SERS application. The SERS activity of the samples was tested by Raman microscopy. The Raman spectra of Rhodamine 6G aqueous solution (c=10−3 mol/dm3 were collected from the patterned and metalized areas. For areas prepared at 40–60 mJ/cm2 laser fluences, the measured Raman intensities have shown a linear dependence on the applied laser fluence, while above 60 mJ/cm2 saturation was observed. The morphology of the SERS active surface areas was investigated by scanning electron microscopy. Finite element modeling was performed in order to simulate the laser-absorption induced heating of the polyimide foil. The simulation resulted in the temporal and spatial distribution of the estimated temperature in the irradiated polyimide sample, which are important for understanding the structure formation process.

  20. Highly sensitive, reproducible and stable SERS substrate based on reduced graphene oxide/silver nanoparticles coated weighing paper

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Guina, E-mail: xiaoguina@shnu.edu.cn; Li, Yunxiang; Shi, Wangzhou; Shen, Leo; Chen, Qi; Huang, Lei, E-mail: leihuang@shnu.edu.cn

    2017-05-15

    Highlights: • We developed a paper-based SERS substrate by gravure and inkjet printing methods. • The S-RGO/AgNPs comoposite structure had higher SERS activity than the pure AgNPs. • The Raman enhancement factor of S-RGO/AgNPs substrate was calculated to be 10{sup 9}. • The paper-based substrate exhibited good reproducibility and long-term stability. - Abstract: Paper-based surface-enhanced Raman scattering (SERS) substrates receive a great deal of attention due to low cost and high flexibility. Herein, we developed an efficient SERS substrate by gravure printing of sulfonated reduced graphene-oxide (S-RGO) thin film and inkjet printing of silver nanoparticles (AgNPs) on weighing paper successively. Malachite green (MG) and rhodamine 6G (R6G) were chosen as probe molecules to evaluate the enhanced performance of the fabricated SERS-active substrates. It was found that the S-RGO/AgNPs composite structure possessed higher enhancement ability than the pure AgNPs. The Raman enhancement factor of S-RGO/AgNPs was calculated to be as large as 10{sup 9}. The minimum detection limit for MG and R6G was down to 10{sup −7} M with good linear responses (R{sup 2} = 0.9996, 0.9983) range from 10{sup −4} M to 10{sup −7} M. In addition, the S-RGO/AgNPs exhibited good uniformity with a relative standard deviation (RSD) of 7.90% measured by 572 points, excellent reproducibility with RSD smaller than 3.36%, and long-term stability with RSD less than 7.19%.

  1. SERS Substrates by the Assembly of Silver Nano cubes: High-Throughput and Enhancement Reliability Considerations

    International Nuclear Information System (INIS)

    Rabin, O.; Lee, S.Y.; Rabin, O.

    2012-01-01

    Small clusters of nanoparticles are ideal substrates for SERS measurements, but the SERS signal enhancement by a particular cluster is strongly dependent on its structural characteristics and the measurement conditions. Two methods for high-throughput assembly of silver nano cubes into small clusters at predetermined locations on a substrate are presented. These fabrication techniques make it possible to study both the structure and the plasmonic properties of hundreds of nanoparticle clusters. The variations in SERS enhancement factors from cluster to cluster were analyzed and correlated with cluster size and configuration, and laser frequency and polarization. Using Raman instruments with 633 nm and 785 nm lasers and linear clusters of nano cubes, an increase in the reproducibility of the enhancement and an increase in the average enhancement values were achieved by increasing the number of nano cubes in the cluster, up to 4 nano cubes per cluster. By examining the effect of cluster configuration, it is shown that linear clusters with nano cubes attached in a face-to-face configuration are not as effective SERS substrates as linear clusters in which nano cubes are attached along an edge

  2. [AgBr colloids prepared by electrolysis and their SERS activity research].

    Science.gov (United States)

    Si, Min-Zhen; Fang, Yan; Dong, Gang; Zhang, Peng-Xiang

    2008-01-01

    Ivory-white AgBr colloids were prepared by means of electrolysis. Two silver rods 1.0 cm in diameter and 10.0 cm long were respectively used as the negative and positive electrodes, the aqueous solution of hexadecyl trimethyl ammonium bromide was used as the electrolyte, and a 7 V direct current was applied on the silver rods for three hours. The obtained AgBr colloids were characterized by UV-Vis spectroscopy, transmission electron microscopy, and SERS using a 514. 5 nm laser line on Renishaw 2000 Raman spectrometer. These particles are about nanometer size and their shapes are as spherical or elliptic, with a slight degree of particle aggregation. The UV-Vis spectra exhibit a large plasmon resonance band at about 292.5 nm, similar to that reported in the literature. The AgBr colloids were very stable at room temperature for months. In order to test if these AgBr colloids can be used for SERS research, methyl orange, Sudan red and pyridine were used. It was found that AgBr colloids have SERS activity to these three molicules. For methyl orange, the intense Raman peaks are at 1 123, 1 146, 1 392, 1 448 and 1 594 cm(-1); for Sudan red, the intense Raman peaks are at 1 141, 1 179, 1 433 and 1 590 cm(-1); and for pyridine, the intense Raman peaks are at 1 003, 1 034 and 1 121 cm(-1). It is noticeable that SERS of methyl orange was observed on AgBr colloids, but not on the gray and yellow silver colloids prepared by traditional means. The possible reason was explained. One major advantage of this means is the absence of the spectral interference such as citrate, BH4- arising from reaction products of the colloids formation process. On AgBr colloids, one can get some molecular SERS impossible to get on the gray and yellow silver colloids.

  3. Alkaline phosphatase labeled SERS active sandwich immunoassay for detection of Escherichia coli

    Science.gov (United States)

    Bozkurt, Akif Goktug; Buyukgoz, Guluzar Gorkem; Soforoglu, Mehmet; Tamer, Ugur; Suludere, Zekiye; Boyaci, Ismail Hakki

    2018-04-01

    In this study, a sandwich immunoassay method utilizing enzymatic activity of alkaline phosphatase (ALP) on 5-bromo-4-chloro-3-indolyl phosphate (BCIP) for Escherichia coli (E. coli) detection was developed using surface enhanced Raman spectroscopy (SERS). For this purpose, spherical magnetic gold coated core-shell nanoparticles (MNPs-Au) and rod shape gold nanoparticles (Au-NRs) were synthesized and modified for immunomagnetic separation (IMS) of E. coli from the solution. In order to specify the developed method to ALP activity, Au-NRs were labeled with this enzyme. After successful construction of the immunoassay, BCIP substrate was added to produce the SERS-active product; 5-bromo-4-chloro-3-indole (BCI). A good linearity (R2 = 0.992) was established between the specific SERS intensity of BCI at 600 cm- 1 and logarithmic E. coli concentration in the range of 1.7 × 101-1.7 × 106 cfu mL- 1. LOD and LOQ values were also calculated and found to be 10 cfu mL- 1 and 30 cfu mL- 1, respectively.

  4. A high-performance and low cost SERS substrate of plasmonic nanopillars on plastic film fabricated by nanoimprint lithography with AAO template

    Science.gov (United States)

    Liu, Long; Zhang, Qian; Lu, Yuanshen; Du, Wei; Li, Bin; Cui, Yushuang; Yuan, Changsheng; Zhan, Peng; Ge, Haixiong; Wang, Zhenling; Chen, Yanfeng

    2017-06-01

    As a powerful spectroscopy technique, surface-enhanced Raman scattering (SERS) can provide non-destructive and sensitive characterization down to a single molecular level. Aiming to the main challenges of high-performance SERS-active substrates for their real-world applications involving the ultra-sensitive and reproducible signals detection and signal uniformity with large-area, herein, a facile and reliable strategy based on combination of thermal imprinting polycarbonate (PC) film with porous anodic aluminum oxide (AAO) mold and E-beam evaporation of gold is provided to fabricate a high-quality SERS-active substrate consisting of ultra-dense hot-spots with large-area uniformity. Two kinds of sub-10 nm gaps were obtained, including the nanogaps between the neighboring gold coated PC-nanopillars and those between gold on the top of the nanopillars and that on the base, which actually build up a three-dimensional (3D) hot-spot network for high-performance SERS detection. The effect of structural parameters on SERS enhancement was investigated numerically and experimentally, and by optimizing the structural parameters, a remarkable average SERS enhancement factor up to of 1.4×108 is achieved and it shows an excellent reproducibility with a relative standard deviation of 18%, which allows for enhanced practicability in the application of quantitative biochemical detection.

  5. A high-performance and low cost SERS substrate of plasmonic nanopillars on plastic film fabricated by nanoimprint lithography with AAO template

    Directory of Open Access Journals (Sweden)

    Long Liu

    2017-06-01

    Full Text Available As a powerful spectroscopy technique, surface-enhanced Raman scattering (SERS can provide non-destructive and sensitive characterization down to a single molecular level. Aiming to the main challenges of high-performance SERS-active substrates for their real-world applications involving the ultra-sensitive and reproducible signals detection and signal uniformity with large-area, herein, a facile and reliable strategy based on combination of thermal imprinting polycarbonate (PC film with porous anodic aluminum oxide (AAO mold and E-beam evaporation of gold is provided to fabricate a high-quality SERS-active substrate consisting of ultra-dense hot-spots with large-area uniformity. Two kinds of sub-10 nm gaps were obtained, including the nanogaps between the neighboring gold coated PC-nanopillars and those between gold on the top of the nanopillars and that on the base, which actually build up a three-dimensional (3D hot-spot network for high-performance SERS detection. The effect of structural parameters on SERS enhancement was investigated numerically and experimentally, and by optimizing the structural parameters, a remarkable average SERS enhancement factor up to of 1.4×108 is achieved and it shows an excellent reproducibility with a relative standard deviation of 18%, which allows for enhanced practicability in the application of quantitative biochemical detection.

  6. Telmisartan activates endothelial nitric oxide synthase via Ser1177 phosphorylation in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Masahiro Myojo

    Full Text Available Because endothelial nitric oxide synthase (eNOS has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177 in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172 and eNOS and the concentration of intracellular guanosine 3',5'-cyclic monophosphate (cGMP. Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.

  7. SERS activity of silver and gold nanostructured thin films deposited by pulsed laser ablation

    Science.gov (United States)

    Agarwal, N. R.; Tommasini, M.; Fazio, E.; Neri, F.; Ponterio, R. C.; Trusso, S.; Ossi, P. M.

    2014-10-01

    Nanostructured Au and Ag thin films were obtained by nanosecond pulsed laser ablation in presence of a controlled Ar atmosphere. Keeping constant other deposition parameters such as target-to-substrate distance, incidence angle, laser wavelength and laser fluence, the film morphology, revealed by SEM, ranges from isolated NPs to island structures and sensibly depends on gas pressure (10-100 Pa) and on the laser pulse number (500-3 × 10). The control of these two parameters allows tailoring the morphology and correspondingly the optical properties of the films. The position and width of the surface plasmon resonance peak, in fact, can be varied with continuity. The films showed remarkable surface-enhanced Raman activity (SERS) that depends on the adopted deposition conditions. Raman maps were acquired on micrometer-sized areas of both silver and gold substrates selected among those with the strongest SERS activity. Organic dyes of interest in cultural heritage studies (alizarin, purpurin) have been also considered for bench marking the substrates produced in this work. Also the ability to detect the presence of biomolecules was tested using lysozyme in a label free configuration.

  8. Gold Incorporated Mesoporous Silica Thin Film Model Surface as a Robust SERS and Catalytically Active Substrate

    Directory of Open Access Journals (Sweden)

    Anandakumari Chandrasekharan Sunil Sekhar

    2016-05-01

    Full Text Available Ultra-small gold nanoparticles incorporated in mesoporous silica thin films with accessible pore channels perpendicular to the substrate are prepared by a modified sol-gel method. The simple and easy spin coating technique is applied here to make homogeneous thin films. The surface characterization using FESEM shows crack-free films with a perpendicular pore arrangement. The applicability of these thin films as catalysts as well as a robust SERS active substrate for model catalysis study is tested. Compared to bare silica film our gold incorporated silica, GSM-23F gave an enhancement factor of 103 for RhB with a laser source 633 nm. The reduction reaction of p-nitrophenol with sodium borohydride from our thin films shows a decrease in peak intensity corresponding to –NO2 group as time proceeds, confirming the catalytic activity. Such model surfaces can potentially bridge the material gap between a real catalytic system and surface science studies.

  9. SERS activity with tenfold detection limit optimization on a type of nanoporous AAO-based complex multilayer substrate

    Science.gov (United States)

    Sui, Chaofan; Wang, Kaige; Wang, Shuang; Ren, Junying; Bai, Xiaohong; Bai, Jintao

    2016-03-01

    Most of SERS applications are constricted by heterogeneous hotspots and aggregates of nanostructure, which result in low sensitivity and poor reproducibility of characteristic signals. This work intends to introduce SERS properties of a type of SERS-active substrate, Au-CuCl2-AAO, which is innovatively developed on a porous anodic alumina oxide (AAO) template. Spectral measuring results of Rhodamine 6G (R6G) on this substrate optimized by controlling morphology and gold thickness showed that enhancement factor (2.30 × 107) and detection limit (10-10 M) were both improved and represented better performance than its template AAO. Homogenous hot spots across the region of interest were achieved by scanning SERS intensity distribution for the band at 1505 cm-1 in 5 × 5 μm2 area. Furthermore, the promising SERS activity of the flower-patterned substrate was theoretically explained through simulation of the electromagnetic field distribution. In addition, this SERS substrate is proposed for applications within the field of chemical and biochemical analyses.Most of SERS applications are constricted by heterogeneous hotspots and aggregates of nanostructure, which result in low sensitivity and poor reproducibility of characteristic signals. This work intends to introduce SERS properties of a type of SERS-active substrate, Au-CuCl2-AAO, which is innovatively developed on a porous anodic alumina oxide (AAO) template. Spectral measuring results of Rhodamine 6G (R6G) on this substrate optimized by controlling morphology and gold thickness showed that enhancement factor (2.30 × 107) and detection limit (10-10 M) were both improved and represented better performance than its template AAO. Homogenous hot spots across the region of interest were achieved by scanning SERS intensity distribution for the band at 1505 cm-1 in 5 × 5 μm2 area. Furthermore, the promising SERS activity of the flower-patterned substrate was theoretically explained through simulation of the

  10. High-Throughput Fabrication of Nanocone Substrates through Polymer Injection Moulding For SERS Analysis in Microfluidic Systems

    DEFF Research Database (Denmark)

    Viehrig, Marlitt; Matteucci, Marco; Thilsted, Anil H.

    analysis. Metal-capped silicon nanopillars, fabricated through a maskless ion etch, are state-of-the-art for on-chip SERS substrates. A dense cluster of high aspect ratio polymer nanocones was achieved by using high-throughput polymer injection moulding over a large area replicating a silicon nanopillar...... structure. Gold-capped polymer nanocones display similar SERS sensitivity as silicon nanopillars, while being easily integrable into a microfluidic chips....

  11. Influence of the OGG1 Ser326Cys polymorphism on oxidatively damaged DNA and repair activity

    DEFF Research Database (Denmark)

    Jensen, Annie Aarup; Løhr, Mille; Eriksen, Louise

    2012-01-01

    of the comet assay. We collected blood samples from 1,019 healthy subjects and genotyped for the OGG1 Ser326Cys polymorphism. We found 49 subjects homozygous for the variant genotype (Cys/Cys) and selected same numbers of age-matched subjects with the heterozygous (Ser/Cys) and homozygous wild-type genotype...

  12. SERS activity of Au nanoparticles coated on an array of carbon nanotube nested into silicon nanoporous pillar

    International Nuclear Information System (INIS)

    Jiang Weifen; Zhang Yanfeng; Wang Yusheng; Xu Lei; Li Xinjian

    2011-01-01

    A novel composite structure, Au nanoparticles coated on a nest-shaped array of carbon nanotube nested into a silicon nanoporous pillar array (Au/NACNT/Si-NPA), was fabricated for surface-enhanced Raman scattering (SERS). The morphology of the Au/NACNT/Si-NPA composite structure was characterized with the aid of scanning electron microscopy, X-ray diffraction instrumentation and Transmission electron microscopy. Compared with SERS of rhodamine 6G (R6G) adsorbed on SERS-active Au substrate reported, the SERS signals of R6G adsorbed on these gold nanoparticles were obviously improved. This was attributed to the enlarged specific surface area for adsorption of target molecules brought by the nest-shaped CNTs structure.

  13. Gold nanostars: Benzyldimethylammonium chloride-assisted synthesis, plasmon tuning, SERS and catalytic activity.

    Science.gov (United States)

    Ndokoye, Pancras; Li, Xinyong; Zhao, Qidong; Li, Tingting; Tade, Moses O; Liu, Shaomin

    2016-01-15

    Fabrication of Au nanostars (AuNSs) can expand the application range of Au nanoparticles because of their high electron density and localized surface plasmon resonance (LSPR) on branches. Exploiting this potential requires further refinement of length of the branches and radius of their tips. To this end, we successfully synthesized AuNSs with uniform and sharply-pointed branches by combining benzyldimethylammonium chloride (BDAC) and cetyltrimethylammonium bromide (CTAB) at low BDAC/CTAB ratios. Once mixed with CTAB, BDAC lowers the critical micelle concentration (CMC) for quick formation of the micelles, which provides favorable growth templates for AuNSs formation. Besides, BDAC increases the concentration of Cl(-), which favors Ag(+) in adsorbing on Au facets. This feature is crucial for the yield boosting and synergic shape control of AuNSs regardless of types of Au seeds used. Use of less amounts of seeds as the center of nucleation benefited sharper and longer growth of the branches. AuNSs exhibited excellent enhancement of surface-enhanced Raman scattering (SERS) intensities as the result of high electron density localized at the tips; however, the enhancement degree varied in accordance with the size of branches. In addition, AuNSs showed high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Efficient catalysis over AuNSs originates from their corners, stepped surfaces and high electron density at the tips. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Generalized green synthesis of Fe{sub 3}O{sub 4}/Ag composites with excellent SERS activity and their application in fungicide detection

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Hongyan; Zhao, Aiwu, E-mail: awzhao@iim.ac.cn [University of Science and Technology of China, Department of Chemistry (China); Wang, Rujing [Chinese Academy of Sciences, Institute of Intelligent Machines (China); Wang, Dapeng [University of Science and Technology of China, Department of Chemistry (China); Wang, Liusan; Gao, Qian; Sun, Henghui [Chinese Academy of Sciences, Institute of Intelligent Machines (China); Li, Lei; He, Qinye [University of Science and Technology of China, Department of Chemistry (China)

    2015-12-15

    This paper reports the generalized green synthesis of a series of Fe{sub 3}O{sub 4}/Ag composites by magnetron sputtering method. The amounts of silver nanoparticles located on the hollow Fe{sub 3}O{sub 4} magnetic nanoparticles can be tuned by controlling the sputtering time. The surfaces of Fe{sub 3}O{sub 4}/Ag composites are rough with high density and numerous Ag nanogaps (which can serve as Raman active hot spots to amplify the Raman signal), providing the sound reliability and reproducibility of Raman detection. With p-aminothiophenol and Rhodamine 6G (R6G) for probe molecules, the surface-enhanced Raman scattering (SERS) properties of these Fe{sub 3}O{sub 4}/Ag composites were studied. It was found that the SERS signal reached the maximum with the sputtering time of 130 s, indicating that this compound had most hot spots. In this paper, we used the composite with the strongest SERS signal for thiram detection, and the detection limit can reach 5 × 10{sup −7} mol/L (about 0.012 ppm), which is lower than the maximal residue limit of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency. The Fe{sub 3}O{sub 4}/Ag composites are readily available, easy to carry, and show great potential for applications in universal SERS substrates in practical SERS detection.

  15. Synthesis and characterization of Ag@Cu nano/microstructure ordered arrays as SERS-active substrates

    Science.gov (United States)

    Zhang, Pinhua; Cui, Guangliang; Xiao, Chuanhai; Zhang, Mingzhe; Chen, Li; Shi, Changmin

    2016-06-01

    We fabricated an Ag decorated Cu (Ag@Cu) nano/microstructure ordered array by facile template-free 2D electrodeposition combined with a galvanic reduction method for SERS applications. The Cu nano/microstructure ordered arrays were first synthesized by a 2D electrodeposition method, then Ag nanocubes were decorated on the arrays by galvanic reduction without any capping agent. The pollution-free surface and edge-to-face heterostructure of Ag nanocubes and Cu nano/microstructure arrays provide the powerful field-enhancements for SERS performance. The results verified that the Ag@Cu nano/microstructure ordered arrays have excellent activity for 4-Mercaptopyridine, and the sensitivity limit is as low as 10-8 M. Therefore, this facile route provides a useful platform for the fabrication of a SERS substrate based on nano/microstructure ordered arrays.

  16. Highly Sensitive and Reproducible SERS Sensor for Biological pH Detection Based on a Uniform Gold Nanorod Array Platform.

    Science.gov (United States)

    Bi, Liyan; Wang, Yunqing; Yang, Ying; Li, Yuling; Mo, Shanshan; Zheng, Qingyin; Chen, Lingxin

    2018-05-09

    Conventional research on surface-enhanced Raman scattering (SERS)-based pH sensors often depends on nanoparticle aggregation, whereas the variability in nanoparticle aggregation gives rise to poor repeatability in the SERS signal. Herein, we fabricated a gold nanorod array platform via an efficient evaporative self-assembly method. The platform exhibits great SERS sensitivity with an enhancement factor of 5.6 × 10 7 and maintains excellent recyclability and reproducibility with relative standard deviation (RSD) values of less than 8%. On the basis of the platform, we developed a highly sensitive bovine serum albumin (BSA)-coated 4-mercaptopyridine (4-MPy)-linked (BMP) SERS-based pH sensor to report pH ranging from pH 3.0 to pH 8.0. The intensity ratio variation of 1004 and 1096 cm -1 in 4-MPy showed excellent pH sensitivity, which decreased as the surrounding pH increased. Furthermore, this BMP SERS-based pH sensor was employed to measure the pH value in C57BL/6 mouse blood. We have demonstrated that the pH sensor has great advantages such as good stability, reliability, and accuracy, which could be extended for the design of point-of-care devices.

  17. Hierarchical Nanogaps within Bioscaffold Arrays as a High-Performance SERS Substrate for Animal Virus Biosensing

    NARCIS (Netherlands)

    Shao, Feng; Lu, Zhicheng; Liu, Chen; Han, Heyou; Chen, Kun; Li, Wentao; He, Qigai; Peng, Hui; Chen, Juanni

    2014-01-01

    A three-dimensional (3D) biomimetic SERS substrate with hierarchical nanogaps was formed on the bioscaffold arrays of cicada wings by one-step and reagents-free ion-sputtering techniques. This approach requires a minimal fabrication effort and cost and offers Ag nanoislands and Ag nanoflowers with

  18. Fabrication of silver nanoparticles embedded into polyvinyl alcohol (Ag/PVA) composite nanofibrous films through electrospinning for antibacterial and surface-enhanced Raman scattering (SERS) activities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhijie; Wu, Yunping [National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials, Henan University, Kaifeng 475004 (China); Wang, Zhihua, E-mail: zhwang@henu.edu.cn [College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004 (China); Zou, Xueyan; Zhao, Yanbao [National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials, Henan University, Kaifeng 475004 (China); Sun, Lei, E-mail: sunlei@hneu.edu.cn [National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials, Henan University, Kaifeng 475004 (China)

    2016-12-01

    Silver nanoparticle-embedded polyvinyl alcohol (PVA) nanofibers were prepared through electrospinning technique, using as antimicrobial agents and surface-enhanced Raman scattering (SERS) substrates. Ag nanoparticles (NPs) were synthesized in liquid phase, followed by evenly dispersing in PVA solution. After electrospinning of the mixed solution at room temperature, the PVA embedded with Ag NPs (Ag/PVA) composite nanofibers were obtained. The morphologies and structures of the as-synthesized Ag nanoparticles and Ag/PVA fibers were characterized by the techniques of transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Ag NPs have an average diameter of 13.8 nm, were found to be uniformly dispersed in PVA nanofibers. The Ag/PVA nanofibers provided robust antibacterial activities against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) microorganisms. It's also found that Ag/PVA nanofibers make a significant contribution to the high sensitivity of SERS to 4-mercaptophenol (4-MPh) molecules. - Highlights: • Ag NPs embedded in the PVA electropun nanofibrous films were synthesized successfully. • The as-synthesized nanofibrous film mats exhibit excellent antibacterial properties and SERS activates. • The mechanism of antibacterial and SERS effects were proposed.

  19. Fabrication of silver nanoparticles embedded into polyvinyl alcohol (Ag/PVA) composite nanofibrous films through electrospinning for antibacterial and surface-enhanced Raman scattering (SERS) activities

    International Nuclear Information System (INIS)

    Zhang, Zhijie; Wu, Yunping; Wang, Zhihua; Zou, Xueyan; Zhao, Yanbao; Sun, Lei

    2016-01-01

    Silver nanoparticle-embedded polyvinyl alcohol (PVA) nanofibers were prepared through electrospinning technique, using as antimicrobial agents and surface-enhanced Raman scattering (SERS) substrates. Ag nanoparticles (NPs) were synthesized in liquid phase, followed by evenly dispersing in PVA solution. After electrospinning of the mixed solution at room temperature, the PVA embedded with Ag NPs (Ag/PVA) composite nanofibers were obtained. The morphologies and structures of the as-synthesized Ag nanoparticles and Ag/PVA fibers were characterized by the techniques of transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Ag NPs have an average diameter of 13.8 nm, were found to be uniformly dispersed in PVA nanofibers. The Ag/PVA nanofibers provided robust antibacterial activities against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) microorganisms. It's also found that Ag/PVA nanofibers make a significant contribution to the high sensitivity of SERS to 4-mercaptophenol (4-MPh) molecules. - Highlights: • Ag NPs embedded in the PVA electropun nanofibrous films were synthesized successfully. • The as-synthesized nanofibrous film mats exhibit excellent antibacterial properties and SERS activates. • The mechanism of antibacterial and SERS effects were proposed.

  20. Therapeutic drug monitoring of flucytosine in serum using a SERS-active membrane system

    Science.gov (United States)

    Berger, Adam G.; White, Ian M.

    2017-02-01

    A need exists for near real-time therapeutic drug monitoring (TDM), in particular for antibiotics and antifungals in patient samples at the point-of-care. To truly fit the point-of-care need, techniques must be rapid and easy to use. Here we report a membrane system utilizing inkjet-fabricated surface enhanced Raman spectroscopy (SERS) sensors that allows sensitive and specific analysis despite the elimination of sophisticated chromatography equipment, expensive analytical instruments, and other systems relegated to the central lab. We utilize inkjet-fabricated paper SERS sensors as substrates for 5FC detection; the use of paper-based SERS substrates leverages the natural wicking ability and filtering properties of microporous membranes. We investigate the use of microporous membranes in the vertical flow assay to allow separation of the flucytosine from whole blood. The passive vertical flow assay serves as a valuable method for physical separation of target analytes from complex biological matrices. This work further establishes a platform for easy, sensitive, and specific TDM of 5FC from whole blood.

  1. SERS activity of Ag decorated nanodiamond and nano-β-SiC, diamond-like-carbon and thermally annealed diamond thin film surfaces.

    Science.gov (United States)

    Kuntumalla, Mohan Kumar; Srikanth, Vadali Venkata Satya Siva; Ravulapalli, Satyavathi; Gangadharini, Upender; Ojha, Harish; Desai, Narayana Rao; Bansal, Chandrahas

    2015-09-07

    In the recent past surface enhanced Raman scattering (SERS) based bio-sensing has gained prominence owing to the simplicity and efficiency of the SERS technique. Dedicated and continuous research efforts have been made to develop SERS substrates that are not only stable, durable and reproducible but also facilitate real-time bio-sensing. In this context diamond, β-SiC and diamond-like-carbon (DLC) and other related thin films have been promoted as excellent candidates for bio-technological applications including real time bio-sensing. In this work, SERS activities of nanodiamond, nano-β-SiC, DLC, thermally annealed diamond thin film surfaces were examined. DLC and thermally annealed diamond thin films were found to show SERS activity without any metal nanostructures on their surfaces. The observed SERS activities of the considered surfaces are explained in terms of the electromagnetic enhancement mechanism and charge transfer resonance process.

  2. SERS active systems of water-soluble polythiophene and plasmonic nanoparticles: preparation and optical properties

    Czech Academy of Sciences Publication Activity Database

    Kazim, Samrana; Pfleger, Jiří; Halašová, Klára; Procházka, M.; Bondarev, D.; Vohlídal, J.

    2011-01-01

    Roč. 55, č. 2 (2011), 23905_1-23905_6 ISSN 1286-0042. [International Symposium on Flexible Organic Electronics /3./. Ouranoupolis, 06.07.2010-09.07.2010] R&D Projects: GA AV ČR KAN100500652; GA MŠk 7E10040; GA ČR GAP208/10/0941 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanocomposite * SERS * .pi.-conjugated polymer s Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.771, year: 2011

  3. Graphene oxide-Ag nanoparticles-pyramidal silicon hybrid system for homogeneous, long-term stable and sensitive SERS activity

    Science.gov (United States)

    Guo, Jia; Xu, Shicai; Liu, Xiaoyun; Li, Zhe; Hu, Litao; Li, Zhen; Chen, Peixi; Ma, Yong; Jiang, Shouzhen; Ning, Tingyin

    2017-02-01

    In our work, few layers graphene oxide (GO) were directly synthesized on Ag nanoparticles (AgNPs) by spin-coating method to fabricate a GO-AgNPs hybrid structure on a pyramidal silicon (PSi) substrate for surface-enhanced Raman scattering (SERS). The GO-AgNPs-PSi substrate showed excellent Raman enhancement effect, the minimum detected concentration for Rhodamine 6G (R6G) can reach 10-12 M, which is one order of magnitude lower than the AgNPs-PSi substrate and two order of magnitude lower than the GO-AgNPs-flat-Si substrate. The linear fit calibration curve with error bars is presented and the value of R2 of 612 and 773 cm-1 can reach 0.986 and 0.980, respectively. The excellent linear response between the Raman intensity and R6G concentrations prove that the prepared GO-AgNPs-PSi substrates can serve as good SERS substrate for molecule detection. The maximum deviations of SERS intensities from 20 positions of the GO-AgNPs-PSi substrate are less than 8%, revealing the high homogeneity of the SERS substrate. The excellent homogeneity of the enhanced Raman signals can be attributed to well-separated pyramid arrays of PSi, the uniform morphology of AgNPs and multi-functions of GO layer. Besides, the uniform GO film can effectively protect AgNPs from oxidation and endow the hybrid system a good stability and long lifetime. This GO-AgNPs-PSi substrate may provide a new way toward practical applications for the ultrasensitive and label-free SERS detection in areas of medicine, food safety and biotechnology.

  4. Marine Longilenes, Oxasqualenoids with Ser-Thr Protein Phosphatase 2A Inhibition Activity

    Directory of Open Access Journals (Sweden)

    Francisco Cen-Pacheco

    2018-04-01

    Full Text Available The red seaweed Laurencia viridis is a rich source of oxygenated secondary metabolites that were derived from squalene. We report here the structures of three novel compounds, (+-longilene peroxide (1, longilene (2, and (+-prelongilene (3 that were isolated from this alga, in addition to other substances, 4 and 5, resulting from their acid-mediated degradation. The effect of compounds 1 and 3 against Ser-Thr protein phosphatase type 2A (PP2A was evaluated, showing that (+-longilene peroxide (1 inhibited PP2A (IC50 11.3 μM. In order to explain the interaction between PP2A and compounds 1 and 3, molecular docking simulations onto the PP2A enzyme-binding region were used.

  5. UVC-induced apoptosis in Dubca cells is independent of JNK activation and p53Ser-15 phosphorylation

    International Nuclear Information System (INIS)

    Chathoth, Shahanas; Thayyullathil, Faisal; Hago, Abdulkader; Shahin, Allen; Patel, Mahendra; Galadari, Sehamuddin

    2009-01-01

    Ultraviolet C (UVC) irradiation in mammalian cell lines activates a complex signaling network that leads to apoptosis. By using Dubca cells as a model system, we report the presence of a UVC-induced apoptotic pathway that is independent of c-Jun N-terminal kinases (JNKs) activation and p53 phosphorylation at Ser 15 . Irradiation of Dubca cells with UVC results in a rapid JNK activation and phosphorylation of its downstream target c-Jun, as well as, phosphorylation of activating transcription factor 2 (ATF2). Pre-treatment with JNK inhibitor, SP600125, inhibited UVC-induced c-Jun phosphorylation without preventing UVC-induced apoptosis. Similarly, inhibition of UVC-induced p53 phosphorylation did not prevent Dubca cell apoptosis, suggesting that p53 Ser-15 phosphorylation is not associated with UVC-induced apoptosis signaling. The pan-caspase inhibitor z-VAD-fmk inhibited UVC-induced PARP cleavage, DNA fragmentation, and ultimately apoptosis of Dubca cells. Altogether, our study clearly indicates that UVC-induced apoptosis is independent of JNK and p53 activation in Dubca cells, rather, it is mediated through a caspase dependent pathway. Our findings are not in line with the ascribed critical role for JNKs activation, and downstream phosphorylation of targets such as c-Jun and ATF2 in UVC-induced apoptosis.

  6. Highly porous nanocomposites based on TiO2-noble metal particles for sensitive detection of water pollutants by SERS

    International Nuclear Information System (INIS)

    Baia, M; Melinte, G; Iancu, V; Baia, L; Barbu-Tudoran, L; Diamandescu, L; Cosoveanu, V; Danciu, V

    2011-01-01

    Highly porous nanocomposites based on TiO2 aerogel and silver colloidal particles were prepared by different methods in order to study their capacity to detect pollutant species adsorbed on metallic nanoparticles surface from aqueous solution. The efficiency of the obtained composites to detect contaminants from water by means of SERS was evaluated using acrylamide and crystal violet as test molecules. It was found that the detection limits depend both on pollutant and composite type, and were determined to be in the range of 10 -1 -10 -4 M for acrylamide and around 10 -5 M for the dye molecule. These results prove the potential of the prepared porous composites for further use in the development of new SERS-based sensors devices.

  7. Highly porous nanocomposites based on TiO2-noble metal particles for sensitive detection of water pollutants by SERS

    Energy Technology Data Exchange (ETDEWEB)

    Baia, M; Melinte, G; Iancu, V; Baia, L [Faculty of Physics, Babes-Bolyai University, 400084, Cluj-Napoca (Romania); Barbu-Tudoran, L [Faculty of Biology and Geology, Babes-Bolyai University, 400015, Cluj-Napoca (Romania); Diamandescu, L [National Institute of Materials Physics, PO Box MG-7, 77125, Bucharest-Magurele (Romania); Cosoveanu, V; Danciu, V, E-mail: lucian.baia@phys.ubbcluj.ro [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 400028, Cluj-Napoca (Romania)

    2011-07-06

    Highly porous nanocomposites based on TiO2 aerogel and silver colloidal particles were prepared by different methods in order to study their capacity to detect pollutant species adsorbed on metallic nanoparticles surface from aqueous solution. The efficiency of the obtained composites to detect contaminants from water by means of SERS was evaluated using acrylamide and crystal violet as test molecules. It was found that the detection limits depend both on pollutant and composite type, and were determined to be in the range of 10{sup -1}-10{sup -4} M for acrylamide and around 10{sup -5} M for the dye molecule. These results prove the potential of the prepared porous composites for further use in the development of new SERS-based sensors devices.

  8. 3D Plasmonic Ensembles of Graphene Oxide and Nobel Metal Nanoparticles with Ultrahigh SERS Activity and Sensitivity

    Directory of Open Access Journals (Sweden)

    Jing Lin

    2016-01-01

    Full Text Available We describe a comparison study on 3D ensembles of graphene oxide (GO and metal nanoparticles (silver nanoparticles (AgNPs, gold nanoparticles (GNPs, and gold nanorods (GNRs for surface-enhanced Raman scattering (SERS application. For the first time, GNRs were successfully assembled on the surfaces of GO by means of electrostatic interactions without adding any surfactant. The SERS properties of GO/AgNPs, GO/GNPs, and GO/GNRs were compared using 2-mercaptopyridine (2-Mpy as probing molecule. We found that GO/AgNPs and GO/GNPs substrates are not suitable for detecting 2-Mpy due to the very strong π-π stacking interaction between the 2-Mpy molecules and sp2 carbon structure of GO. Conversely, the GO/GNRs substrates show ultrahigh SERS activity and sensitivity of 2-Mpy with the detection limit as low as ~10-15 M, which is ~2-3 orders of magnitude higher than that of the corresponding GNRs.

  9. Synthesis of silver nanoparticles in the presence of diethylaminoethyl-dextran hydrochloride polymer and their SERS activity

    Science.gov (United States)

    Mikac, L.; Jurkin, T.; Štefanić, G.; Ivanda, Mile; Gotić, Marijan

    2017-09-01

    The silver nanoparticles (AgNPs) were synthesized upon γ-irradiation of AgNO3 precursor suspensions in the presence of diethylaminoethyl-dextran hydrochloride (DEAE-dextran) cationic polymer as a stabilizer. The dose rate of γ-irradiation was 32 kGy h-1, and absorbed doses were 30 and 60 kGy. The γ-irradiation of the precursor suspension at acidic or neutral pH conditions produced predominantly the silver(I) chloride (AgCl) particles, because of the poor solubility of AgCl already present in the precursor suspension. The origin of AgCl in the precursor suspension was due to the presence of chloride ions in DEAE-dextran hydrochloride polymer. The addition of ammonia to the precursor suspension dissolved the AgCl precipitate, and the γ-irradiation of such colourless suspension at alkali pH produced a stable aqueous suspension with rather uniform spherical AgNPs of approximately 30 nm in size. The size of AgNPs was controlled by varying the AgNO3/DEAE-dextran concentration in the suspensions. The surface-enhanced Raman scattering (SERS) activities of synthesized AgNPs were examined using organic molecules rhodamine 6G, pyridine and 4-mercaptobenzoic acid (4-MBA). The NaBH4 was used as SERS aggregation agent. The SERS results have shown that in the presence of synthesized AgNPs, it was possible to detect low concentration of tested compounds.

  10. Field-assisted synthesis of SERS-active silver nanoparticles using conducting polymers

    Science.gov (United States)

    Xu, Ping; Jeon, Sea-Ho; Mack, Nathan H.; Doorn, Stephen K.; Williams, Darrick J.; Han, Xijiang; Wang, Hsing-Lin

    2010-08-01

    A gradient of novel silver nanostructures with widely varying sizes and morphologies is fabricated on a single conducting polyaniline-graphite (P-G) membrane with the assistance of an external electric field. It is believed that the formation of such a silver gradient is a synergetic consequence of the generation of a silver ion concentration gradient along with an electrokinetic flow of silver ions in the field-assisted model, which greatly influences the nucleation and growth mechanism of Ag particles on the P-G membrane. The produced silver dendrites, flowers and microspheres, with sharp edges, intersections and bifurcations, all present strong surface enhanced Raman spectroscopy (SERS) responses toward an organic target molecule, mercaptobenzoic acid (MBA). This facile field-assisted synthesis of Ag nanoparticles via chemical reduction presents an alternative approach to nanomaterial fabrication, which can yield a wide range of unique structures with enhanced optical properties that were previously inaccessible by other synthetic routes.A gradient of novel silver nanostructures with widely varying sizes and morphologies is fabricated on a single conducting polyaniline-graphite (P-G) membrane with the assistance of an external electric field. It is believed that the formation of such a silver gradient is a synergetic consequence of the generation of a silver ion concentration gradient along with an electrokinetic flow of silver ions in the field-assisted model, which greatly influences the nucleation and growth mechanism of Ag particles on the P-G membrane. The produced silver dendrites, flowers and microspheres, with sharp edges, intersections and bifurcations, all present strong surface enhanced Raman spectroscopy (SERS) responses toward an organic target molecule, mercaptobenzoic acid (MBA). This facile field-assisted synthesis of Ag nanoparticles via chemical reduction presents an alternative approach to nanomaterial fabrication, which can yield a wide range

  11. Transition in Survival From Low-Dose Hyper-Radiosensitivity to Increased Radioresistance Is Independent of Activation of ATM SER1981 Activity

    International Nuclear Information System (INIS)

    Krueger, Sarah A.; Collis, Spencer J.; Joiner, Michael C.; Wilson, George D.; Marples, Brian

    2007-01-01

    Purpose: The molecular basis of low-dose hyper-radiosensitivity (HRS) is only partially understood. The aim of this study was to define the roles of ataxia telangiectasia mutated (ATM) activity and the downstream ATM-dependent G 2 -phase cell cycle checkpoint in overcoming HRS and triggering radiation resistance. Methods and Materials: Survival was measured using a high-resolution clonogenic assay. ATM Ser1981 activation was measured by Western blotting. The role of ATM was determined in survival experiments after molecular (siRNA) and chemical (0.4 mM caffeine) inhibition and chemical (20 μg/mL chloroquine, 15 μM genistein) activation 4-6 h before irradiation. Checkpoint responsiveness was assessed in eight cell lines of differing HRS status using flow cytometry to quantify the progression of irradiated (0-2 Gy) G 2 -phase cells entering mitosis, using histone H3 phosphorylation analysis. Results: The dose-response pattern of ATM activation was concordant with the transition from HRS to radioresistance. However, ATM activation did not play a primary role in initiating increased radioresistance. Rather, a relationship was discovered between the function of the downstream ATM-dependent early G 2 -phase checkpoint and the prevalence and overcoming of HRS. Four cell lines that exhibited HRS failed to show low-dose ( 2 -phase checkpoint. These data suggest that clinical exploitation of HRS could be achieved by combining radiotherapy with chemotherapeutic agents that modulate this cell cycle checkpoint

  12. High-performance SERS substrate based on hybrid structure of graphene oxide/AgNPs/Cu film@pyramid Si

    Science.gov (United States)

    Li, Zhe; Xu, Shi Cai; Zhang, Chao; Liu, Xiao Yun; Gao, Sai Sai; Hu, Li Tao; Guo, Jia; Ma, Yong; Jiang, Shou Zhen; Si, Hai Peng

    2016-12-01

    We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/copper film covered silicon pyramid arrays (GO/AgNPs/PCu@Si) by a low-cost and simple method. The GO/AgNPs/PCu@Si substrate presents high sensitivity, good homogeneity and well stability with R6G molecules as a probe. The detected concentration of Rhodamine 6 G (R6G) is as low as 10-15 M. These sensitive SERS behaviors are also confirmed in theory via a commercial COMSOL software, the electric field enhancement is not only formed between the AgNPs, but also formed between the AgNPs and Cu film. And the GO/AgNPs/PCu@Si substrates also present good property on practical application for the detection of methylene blue (MB) and crystal violet (CV). This work may offer a novel and practical method to facilitate the SERS applications in areas of medicine, food safety and biotechnology.

  13. SERPENS CLUSTER B AND VV SER OBSERVED WITH HIGH SPATIAL RESOLUTION AT 70, 160, AND 350 μm

    International Nuclear Information System (INIS)

    Harvey, Paul; Dunham, Michael M.

    2009-01-01

    We report on diffraction-limited observations in the far-infrared (FIR) and submillimeter of the Cluster B region of Serpens (G3-G6 Cluster) and of the Herbig Be star to the south, VV Ser. The observations were made with the Spitzer/MIPS instrument in fine-scale mode at 70 μm, in a normal mapping mode at 160 μm (VV Ser only), and the Caltech Submillimeter Observatory (CSO) Submillimeter High Angular Resolution Camera II (SHARC-II) camera at 350 μm (Cluster B only). We use these data to define the spectral energy distributions of the tightly grouped members of Cluster B, many of whose spectral energy distribution (SED)'s peak in the FIR. We compare our results to those of the c2d survey of Serpens and to published models for the FIR emission from VV Ser. We find that values of L bol and T bol calculated with our new photometry show only modest changes from previous values, and that most source SED classifications remain unchanged.

  14. Cube-like Fe3O4@SiO2@Au@Ag magnetic nanoparticles: a highly efficient SERS substrate for pesticide detection

    Science.gov (United States)

    Sun, Mei; Zhao, Aiwu; Wang, Dapeng; Wang, Jin; Chen, Ping; Sun, Henghui

    2018-04-01

    As a novel surface-enhanced Raman spectroscopic (SERS) nanocomposite, cube-like Fe3O4@SiO2@Au@Ag magnetic nanoparticles (NPs) were synthesized for the first time. Cube-like α-Fe2O3 NPs with uniform size were achieved by optimizing reaction temperature and time. Firstly, the cube-like Fe3O4@SiO2 with good dispersity was achieved by calcining α-Fe2O3@SiO2 NPs in hydrogen atmosphere at 360 °C for 2.5 h, followed by self-assembling a PEI shell via sonication. Furthermore, the Au@Ag particles were densely assembled on the Fe3O4@SiO2 NPs to form the Fe3O4@SiO2@Au@Ag composite structure via strong Ag-N interaction. The obtained nanocomposites exhibited an excellent SERS behavior, reflected by the low detection of limit (p-ATP) at the 5 × 10-14 M level. Moreover, these nanocubes were used for the detection of thiram, and the detection limit can reach 5 × 10-11 M. Meanwhile, the U.S. Environmental Protection Agency specifies that the residue in fruit must be lower than 7 ppm. Hence, the resulting substrate with high SERS activity has great practical potential applications in the rapid detection of chemical, biological, and environment pollutants with a simple portable Raman instrument at trace level.

  15. Graphene oxide-Ag nanoparticles-pyramidal silicon hybrid system for homogeneous, long-term stable and sensitive SERS activity

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jia [School of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Xu, Shicai [Shandong Provincial Key Laboratory of Biophysics, College of Physics and Electronic Information, Dezhou University, Dezhou 253023 (China); Liu, Xiaoyun; Li, Zhe; Hu, Litao; Li, Zhen; Chen, Peixi; Ma, Yong [School of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Jiang, Shouzhen, E-mail: jiang_sz@126.com [School of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Shandong Provincial Key Laboratory of Optics and Photonic Device, Jinan 250014 (China); Ning, Tingyin [School of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Shandong Provincial Key Laboratory of Optics and Photonic Device, Jinan 250014 (China)

    2017-02-28

    Highlights: • We directly grown AgNPs on substrate by annealing method in the quartz tube. Compare with spin-coating Ag nanoparticles solution method, we got more uniform distribution of AgNPs and the AgNPs better adsorption on the substrate. • We use a simple and lost-cost method to obtain the pyramidal silicon (PSi). The PSi possessing well-separated pyramid arrays can make contribution to the homogeneity and sensitivity of the substrate. • In our work, graphene oxide (GO) film is uniformly deposited on AgNPs and PSi by using a spin-coating method. The GO films endow the hybrid system a good stability and enhance the homogeneity and sensitivity of the substrate. - Abstract: In our work, few layers graphene oxide (GO) were directly synthesized on Ag nanoparticles (AgNPs) by spin-coating method to fabricate a GO-AgNPs hybrid structure on a pyramidal silicon (PSi) substrate for surface-enhanced Raman scattering (SERS). The GO-AgNPs-PSi substrate showed excellent Raman enhancement effect, the minimum detected concentration for Rhodamine 6G (R6G) can reach 10{sup −12} M, which is one order of magnitude lower than the AgNPs-PSi substrate and two order of magnitude lower than the GO-AgNPs-flat-Si substrate. The linear fit calibration curve with error bars is presented and the value of R{sup 2} of 612 and 773 cm{sup −1} can reach 0.986 and 0.980, respectively. The excellent linear response between the Raman intensity and R6G concentrations prove that the prepared GO-AgNPs-PSi substrates can serve as good SERS substrate for molecule detection. The maximum deviations of SERS intensities from 20 positions of the GO-AgNPs-PSi substrate are less than 8%, revealing the high homogeneity of the SERS substrate. The excellent homogeneity of the enhanced Raman signals can be attributed to well-separated pyramid arrays of PSi, the uniform morphology of AgNPs and multi-functions of GO layer. Besides, the uniform GO film can effectively protect AgNPs from oxidation and endow

  16. Ser reina

    Directory of Open Access Journals (Sweden)

    José Manuel NIETO SORIA

    2006-07-01

    Full Text Available L’historiographie du règne des Rois Catholiques, héritière directe de celle des autres Trastamare, se caractérise par son étroite relation avec des enjeux politiques concrets. L’activité historiographie s’est ainsi inscrite elle-même dans le cadre des conflits politiques en cours. C’est pourquoi la royauté d’Isabelle Ire de Castille impliqua une bonne part de la production historiographique de cettte époque : soit qu’on dénonçât un déficit de légitimité dû à sa condition féminine, soit qu’on démentît, au contraire, ce déficit en attribuant à la reine des qualités « masculines ». Bien entendu, ces débats furent fonction de l’engagement politique de chacun des historiens.La cronística y la historiografía del reinado de los Reyes Católicos, como directas herederas de la labor historiográfica de la época de los monarcas Trastámara, se caracterizó por su estrecha vinculación con intereses políticos concretos, inscribiéndose la propia actividad historiográfica en el marco de los conflictos políticos en curso. Por ello, la dimensión regia de Isabel I de Castilla supuso una dimensión significativa del quehacer historiográfico de la época, bien para plantear un déficit de legitimidad por razón de su propia condición femenina, bien para negar tal déficit con la atribución de “cualidades masculinas” en su persona. De este modo, la toma en consideración del hecho de “ser reina” representó una dimensión significativa del quehacer historiográfico, de acuerdo siempre con los compromisos políticos de los distintos historiadores de la época.

  17. Toward practical SERS sensing

    Science.gov (United States)

    Zhao, Yiping

    2012-06-01

    Since its discovery more than 30 years ago, surface-enhanced Raman scattering (SERS) has been recognized as a highly sensitive detection technique for chemical and biological sensing and medical diagnostics. However, the practical application of this remarkably sensitive technique has not been widely accepted as a viable diagnostic method due to the difficulty in preparing robust and reproducible substrates that provide maximum SERS enhancement. Here, we demonstrate that the aligned silver nanorod (AgNR) array substrates engineered by the oblique angle deposition method are capable of providing extremely high SERS enhancement factors (>108). The substrates are large area, uniform, reproducible, and compatible with general microfabrication process. The enhancement factor depends strongly on the length and shape of the Ag nanorods and the underlying substrate coating. By optimizing AgNR SERS substrates, we show that SERS is able to detect trace amount of toxins, virus, bacteria, or other chemical and biological molecules, and distinguish different viruses/bacteria and virus/bacteria strains. The substrate can be tailored into a multi-well chip for high throughput screening, integrated into fiber tip for portable sensing, incorporated into fluid/microfluidic devices for in situ real-time monitoring, fabricated onto a flexible substrate for tracking and identification, or used as on-chip separation device for ultra-thin layer chromatography and diagnostics. By combining the unique SERS substrates with a handheld Raman system, it can become a practical and portable sensor system for field applications. All these developments have demonstrated that AgNR SERS substrates could play an important role in the future for practical clinical, industrial, defense, and security sensing applications.

  18. The kinase activity of the Ser/Thr kinase BUB1 promotes TGF-β signaling.

    Science.gov (United States)

    Nyati, Shyam; Schinske-Sebolt, Katrina; Pitchiaya, Sethuramasundaram; Chekhovskiy, Katerina; Chator, Areeb; Chaudhry, Nauman; Dosch, Joseph; Van Dort, Marcian E; Varambally, Sooryanarayana; Kumar-Sinha, Chandan; Nyati, Mukesh Kumar; Ray, Dipankar; Walter, Nils G; Yu, Hongtao; Ross, Brian Dale; Rehemtulla, Alnawaz

    2015-01-06

    Transforming growth factor-β (TGF-β) signaling regulates cell proliferation and differentiation, which contributes to development and disease. Upon binding TGF-β, the type I receptor (TGFBRI) binds TGFBRII, leading to the activation of the transcription factors SMAD2 and SMAD3. Using an RNA interference screen of the human kinome and a live-cell reporter for TGFBR activity, we identified the kinase BUB1 (budding uninhibited by benzimidazoles-1) as a key mediator of TGF-β signaling. BUB1 interacted with TGFBRI in the presence of TGF-β and promoted the heterodimerization of TGFBRI and TGFBRII. Additionally, BUB1 interacted with TGFBRII, suggesting the formation of a ternary complex. Knocking down BUB1 prevented the recruitment of SMAD3 to the receptor complex, the phosphorylation of SMAD2 and SMAD3 and their interaction with SMAD4, SMAD-dependent transcription, and TGF-β-mediated changes in cellular phenotype including epithelial-mesenchymal transition (EMT), migration, and invasion. Knockdown of BUB1 also impaired noncanonical TGF-β signaling mediated by the kinases AKT and p38 MAPK (mitogen-activated protein kinase). The ability of BUB1 to promote TGF-β signaling depended on the kinase activity of BUB1. A small-molecule inhibitor of the kinase activity of BUB1 (2OH-BNPP1) and a kinase-deficient mutant of BUB1 suppressed TGF-β signaling and formation of the ternary complex in various normal and cancer cell lines. 2OH-BNPP1 administration to mice bearing lung carcinoma xenografts reduced the amount of phosphorylated SMAD2 in tumor tissue. These findings indicated that BUB1 functions as a kinase in the TGF-β pathway in a role beyond its established function in cell cycle regulation and chromosome cohesion. Copyright © 2015, American Association for the Advancement of Science.

  19. Design of analog-type high-speed SerDes using digital components for optical chip-to-chip link

    Science.gov (United States)

    Sangirov, Jamshid; Nguyen, Nga T. H.; Ngo, Trong-Hieu; Im, Dong-min; Ukaegbu, Augustine I.; Lee, Tae-Woo; Cho, Mu Hee; Park, Hyo-Hoon

    2010-02-01

    An analog-type high-speed serializer/deserializer (SerDes) has been designed for optical links especially between CPU and memory. The circuit uses a system clock and its phases to multiplex data to the serial link which avoids the need for a PLL-based high frequency clock generation used in serializing parallel data as in conventional SerDes design. The multiplexed link combined with the de-serializing clock is used as a reference signal for de-serialization. The SerDes is being designed in a 0.13 μm Si-CMOS technology. The fabricated serializer has a core chip size of 360 x750 μm2. Power dissipation for the SerDes is 71.4 mW operating up to 6.5 Gbps.

  20. Preparação e caracterização de substratos SERS ativos: um estudo da adsorção do cristal violeta sobre nanopartículas de prata Preparation and characterization of SERS-active substrates: a study of the crystal violet adsorption on silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Henrique de Santana

    2006-04-01

    Full Text Available The structural characterization of molecules used in the sterilization of blood for transfusions, such as crystal violet (CV, is relevant for understanding the action of these prophylactic drugs. The characterization is feasible by surface enhanced resonance Raman spectroscopy (SERRS of CV in solution or on surfaces. The limit of detection of CV by SERRS, in the presence of colloidal particles, using 514.5 nm as excitation radiation, was found to be around 1 ppb. The characterization of CV was also made by SERS, by using different active-particles-containing substrates, proving the versatility of this technique for the study of such structures. The results suggest that the controlled production of highly efficient SERS-active substrates may allow qualitative and quantitative analysis, with high sensitivity, with potential applications in medical and environmental fields.

  1. A green, reusable SERS film with high sensitivity for in-situ detection of thiram in apple juice

    Science.gov (United States)

    Sun, Hongbao; Liu, Hai; Wu, Yiyong

    2017-09-01

    We report a green and reusable surface-enhanced Raman scattering (SERS) film based on PMMA/Ag NPs/graphene. By using this Raman substrate, the SERS signals of R6G were significantly enhanced reaching a minimum detectable concentration of 5 × 10-8 M, due to having lots of hot spots adhered backside to the exposed graphene. The SERS film can be used for in-situ monitoring of trace thiram in apple juice with a detection limit of 1 × 10-6 M (0.24 ppm), which is below the maximal residue limit (MRL) of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency (EPA). Furthermore, reusability studies show that the SERS film can be used repeatedly. In addition, the graphene-enhanced SERS technique shows great potential applications for the in-situ detection and identification of pesticide residues in environmental water, fruits and vegetables.

  2. Highly Sensitive Magnetic-SERS Dual-Function Silica Nanoprobes for Effective On-Site Organic Chemical Detection

    Science.gov (United States)

    Jeong, Cheolhwan; Kim, Hyung-Mo; Park, So Yeon; Cha, Myeong Geun; Park, Sung-Jun; Kyeong, San; Pham, Xuan-Hung; Hahm, Eunil; Ha, Yuna; Jeong, Dae Hong; Jun, Bong-Hyun; Lee, Yoon-Sik

    2017-01-01

    We report magnetic silver nanoshells (M-AgNSs) that have both magnetic and SERS properties for SERS-based detection. The M-AgNSs are composed of hundreds of Fe3O4 nanoparticles for rapid accumulation and bumpy silver shell for sensitive SERS detection by near-infrared laser excitation. The intensity of the SERS signal from the M-AgNSs was strong enough to provide single particle-level detection. We obtained much stronger SERS signal intensity from the aggregated M-AgNSs than from the non-aggregated AgNSs. 4-Fluorothiophenol was detected at concentrations as low as 1 nM, which corresponds to 0.16 ppb. The limit of detection for tetramethylthiuram disulfide was 10 μM, which corresponds to 3 ppm. The M-AgNSs can be used to detect trace amounts of organic molecules using a portable Raman system. PMID:28608835

  3. Highly Sensitive Magnetic-SERS Dual-Function Silica Nanoprobes for Effective On-Site Organic Chemical Detection

    Directory of Open Access Journals (Sweden)

    Cheolhwan Jeong

    2017-06-01

    Full Text Available We report magnetic silver nanoshells (M-AgNSs that have both magnetic and SERS properties for SERS-based detection. The M-AgNSs are composed of hundreds of Fe3O4 nanoparticles for rapid accumulation and bumpy silver shell for sensitive SERS detection by near-infrared laser excitation. The intensity of the SERS signal from the M-AgNSs was strong enough to provide single particle-level detection. We obtained much stronger SERS signal intensity from the aggregated M-AgNSs than from the non-aggregated AgNSs. 4-Fluorothiophenol was detected at concentrations as low as 1 nM, which corresponds to 0.16 ppb. The limit of detection for tetramethylthiuram disulfide was 10 μM, which corresponds to 3 ppm. The M-AgNSs can be used to detect trace amounts of organic molecules using a portable Raman system.

  4. Mass spectrometry and site-directed mutagenesis identify several autophosphorylated residues required for the activity of PrkC, a Ser/Thr kinase from Bacillus subtilis

    DEFF Research Database (Denmark)

    Madec, Edwige; Stensballe, Allan; Kjellström, Sven

    2003-01-01

    We have shown recently that PrkC, which is involved in developmental processes in Bacillus subtilis, is a Ser/Thr kinase with features of the receptor kinase family of eukaryotic Hanks kinases. In this study, we expressed and purified from Escherichia coli the cytoplasmic domain of PrkC containing...... the kinase and a short juxtamembrane region. This fragment, which we designate PrkCc, undergoes autophosphorylation in E.coli. PrkCc is further autophosphorylated in vitro, apparently through a trans-kinase, intermolecular reaction. PrkC also displays kinase activity with myelin basic protein. Using high...... mass accuracy electrospray tandem mass spectrometry (LC-MS/MS) and nanoelectrospray tandem mass spectrometry, we identified seven phosphorylated threonine and one serine residue in PrkCc. All the corresponding residues were replaced by systematic site-directed mutagenesis and the purified mutant...

  5. Effect of resistance exercise under conditions of reduced blood insulin on AMPKα Ser485/491 inhibitory phosphorylation and AMPK pathway activation.

    Science.gov (United States)

    Kido, Kohei; Yokokawa, Takumi; Ato, Satoru; Sato, Koji; Fujita, Satoshi

    2017-08-01

    Insulin stimulates skeletal muscle glucose uptake via activation of the protein kinase B/Akt (Akt) pathway. Recent studies suggest that insulin downregulates AMP-activated protein kinase (AMPK) activity via Ser485/491 phosphorylation of the AMPK α-subunit. Thus lower blood insulin concentrations may induce AMPK signal activation. Acute exercise is one method to stimulate AMPK activation; however, no study has examined the relationship between blood insulin levels and acute resistance exercise-induced AMPK pathway activation. Based on previous findings, we hypothesized that the acute resistance exercise-induced AMPK pathway activation would be augmented by disruptions in insulin secretion through a decrease in AMPKα Ser485/491 inhibitory phosphorylation. To test the hypothesis, 10-wk-old male Sprague-Dawley rats were administered the toxin streptozotocin (STZ; 55 mg/kg) to destroy the insulin secreting β-cells. Three days postinjection, the right gastrocnemius muscle from STZ and control rats was subjected to resistance exercise by percutaneous electrical stimulation. Animals were killed 0, 1, or 3 h later; activation of the Akt/AMPK and downstream pathways in the muscle tissue was analyzed by Western blotting and real-time PCR. Notably, STZ rats showed a significant decrease in basal Akt and AMPKα Ser485/491 phosphorylation, but substantial exercise-induced increases in both AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79 phosphorylation were observed. Although no significant impact on resistance exercise-induced Akt pathway activation or glucose uptake was found, resistance exercise-induced peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 α (PGC-1α) gene expression was augmented by STZ treatment. Collectively, these data suggest that circulating insulin levels may regulate acute resistance exercise-induced AMPK pathway activation and AMPK-dependent gene expression relating to basal AMPKα Ser485/491 phosphorylation. Copyright © 2017

  6. 3D Plasmonic Ensembles of Graphene Oxide and Nobel Metal Nanoparticles with Ultrahigh SERS Activity and Sensitivity

    OpenAIRE

    Jing Lin; Xiansong Wang; Guangxia Shen; Daxiang Cui

    2016-01-01

    We describe a comparison study on 3D ensembles of graphene oxide (GO) and metal nanoparticles (silver nanoparticles (AgNPs), gold nanoparticles (GNPs), and gold nanorods (GNRs)) for surface-enhanced Raman scattering (SERS) application. For the first time, GNRs were successfully assembled on the surfaces of GO by means of electrostatic interactions without adding any surfactant. The SERS properties of GO/AgNPs, GO/GNPs, and GO/GNRs were compared using 2-mercaptopyridine (2-Mpy) as probing mole...

  7. Melanin-Associated Synthesis of SERS-Active Nanostructures and the Application for Monitoring of Intracellular Melanogenesis

    OpenAIRE

    Haixin Dong; Zhiming Liu; Huiqing Zhong; Hui Yang; Yan Zhou; Yuqing Hou; Jia Long; Jin Lin; Zhouyi Guo

    2017-01-01

    Melanin plays an indispensable role in the human body. It serves as a biological reducer for the green synthesis of precious metal nanoparticles. Melanin?Ag nanocomposites were successfully produced which exhibited very strong surface-enhanced Raman scattering (SERS) effect because of the reducibility property of melanin. A melanin?Ag composite structure was synthesized in situ in melanin cells, and SERS technique was performed for the rapid imaging and quantitative assay of intracellular mel...

  8. Security effectiveness review (SER)

    International Nuclear Information System (INIS)

    Kouprianova, I.; Ek, D.; Showalter, R.; Bergman, M.

    1998-01-01

    As part of the on-going DOE/Russian MPC and A activities at the Institute of Physics and Power Engineering (IPPE) and in order to provide a basis for planning MPC and A enhancements, an expedient method to review the effectiveness of the MPC and A system has been adopted. These reviews involve the identification of appropriate and cost-effective enhancements of facilities at IPPE. This effort requires a process that is thorough but far less intensive than a traditional vulnerability assessment. The SER results in a quick assessment of current and needed enhancements. The process requires preparation and coordination between US and Russian analysts before, during, and after information gathering at the facilities in order that the analysis is accurate, effective, and mutually agreeable. The goal of this paper is to discuss the SER process, including the objectives, time scale, and lessons learned at IPPE

  9. SERS- and Electrochemically Active 3D Plasmonic Liquid Marbles for Molecular-Level Spectroelectrochemical Investigation of Microliter Reactions.

    Science.gov (United States)

    Koh, Charlynn Sher Lin; Lee, Hiang Kwee; Phan-Quang, Gia Chuong; Han, Xuemei; Lee, Mian Rong; Yang, Zhe; Ling, Xing Yi

    2017-07-17

    Liquid marbles are emergent microreactors owing to their isolated environment and the flexibility of materials used. Plasmonic liquid marbles (PLMs) are demonstrated as the smallest spectroelectrochemical microliter-scale reactor for concurrent spectro- and electrochemical analyses. The three-dimensional Ag shell of PLMs are exploited as a bifunctional surface-enhanced Raman scattering (SERS) platform and working electrode for redox process modulation. The combination of SERS and electrochemistry (EC) capabilities enables in situ molecular read-out of transient electrochemical species, and elucidate the potential-dependent and multi-step reaction dynamics. The 3D configuration of our PLM-based EC-SERS system exhibits 2-fold and 10-fold superior electrochemical and SERS performance than conventional 2D platforms. The rich molecular-level electrochemical insights and excellent EC-SERS capabilities offered by our 3D spectroelectrochemical system are pertinent in charge transfer processes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Surface-enhanced vibrational spectroscopy of B vitamins: what is the effect of SERS-active metals used?

    Science.gov (United States)

    Kokaislová, A; Matějka, P

    2012-05-01

    Surface-enhanced Raman scattering (SERS) spectroscopy and surface-enhanced infrared absorption (SEIRA) spectroscopy are analytical tools suitable for the detection of small amounts of various analytes adsorbed on metal surfaces. During recent years, these two spectroscopic methods have become increasingly important in the investigation of adsorption of biomolecules and pharmaceuticals on nanostructured metal surfaces. In this work, the adsorption of B-group vitamins pyridoxine, nicotinic acid, folic acid and riboflavin at electrochemically prepared gold and silver substrates was investigated using Fourier transform SERS spectroscopy at an excitation wavelength of 1,064 nm. Gold and silver substrates were prepared by cathodic reduction on massive platinum targets. In the case of gold substrates, oxidation-reduction cycles were applied to increase the enhancement factor of the gold surface. The SERS spectra of riboflavin, nicotinic acid, folic acid and pyridoxine adsorbed on silver substrates differ significantly from SERS spectra of these B-group vitamins adsorbed on gold substrates. The analysis of near-infrared-excited SERS spectra reveals that each of B-group vitamin investigated interacts with the gold surface via a different mechanism of adsorption to that with the silver surface. In the case of riboflavin adsorbed on silver substrate, the interpretation of surface-enhanced infrared absorption (SEIRA) spectra was also helpful in investigation of the adsorption mechanism.

  11. Highly sensitive and stable Ag@SiO2 nanocubes for label-free SERS-photoluminescence detection of biomolecules

    Science.gov (United States)

    Nguyen, Minh-Kha; Su, Wei-Nien; Chen, Ching-Hsiang; Rick, John; Hwang, Bing-Joe

    2017-03-01

    Surface-enhanced Raman scattering (SERS) and fluorescence microscopy are a widely used biological and chemical characterization techniques. However, the peak overlapping in multiplexed experiments and rapid photobleaching of fluorescent organic dyes is still the limitations. When compared to Ag nanocubes (NCs), higher SERS sensitivities can be obtained with thin shelled silica Ag@SiO2 NCs, in contrast metal-enhanced photoluminescence (MEPL) is only found with NCs that have thicker silica shells. A 'dual functionality' represented by the simultaneous strengthening of SERS and MEPL signals can be achieved by mixing Ag@SiO2 NCs, with a silica shell thickness of 1.5 nm and 4.4 nm. This approach allows both the Ag@SiO2 NCs SERS and MEPL sensitivities to be maintained at 90% after 12 weeks of storage. Based on the distinguished detection of creatinine and flavin adenine dinucleotide in the mixture, the integration of SERS and MEPL together on a stable single plasmonic nanoparticle platform offers an opportunity to enhance both biomarker detection sensitivity and specificity.

  12. SERS active Ag encapsulated Fe@SiO2 nanorods in electromagnetic wave absorption and crystal violet detection.

    Science.gov (United States)

    Senapati, Samarpita; Srivastava, Suneel Kumar; Singh, Shiv Brat; Kulkarni, Ajit R

    2014-11-01

    The present work is focused on the preparation of Fe nanorods by the chemical reduction of FeCl3 (aq) using NaBH4 in the presence of glycerol as template followed by annealing of the product at 500°C in the presence of H2 gas flow. Subsequently, its surface has been modified by silica followed by silver nanoparticles to form silica coated Fe (Fe@SiO2) and Ag encapsulated Fe@SiO2 nanostructure employing the Stöber method and silver mirror reaction respectively. XRD pattern of the products confirmed the formation of bcc phase of iron and fcc phase of silver, though silica remained amorphous. FESEM images established the growth of iron nanorods from the annealed product and also formation of silica and silver coating on its surface. The appearance of the characteristics bands in FTIR confirmed the presence of SiO2 on the Fe surface. Magnetic measurements at room temperature indicated the ferromagnetic behavior of as prepared iron nanorods, Fe@SiO2 and silver encapsulated Fe@SiO2 nanostructures. All the samples exhibited strong microwave absorption property in the high frequency range (10GHz), though it is superior for Ag encapsulated Fe@SiO2 (-14.7dB) compared with Fe@SiO2 (-9.7dB) nanostructures of the same thickness. The synthesized Ag encapsulated Fe@SiO2 nanostructure also exhibited the SERS phenomena, which is useful in the detection of the carcinogenic dye crystal violet (CV) upto the concentration of 10(-10)M. All these findings clearly demonstrate that the Ag encapsulated Fe@SiO2 nanostructure could efficiently be used in the environmental remediation. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Transformation of Ag nanocubes into Ag-Au hollow nanostructures with enriched Ag contents to improve SERS activity and chemical stability.

    Science.gov (United States)

    Yang, Yin; Zhang, Qiang; Fu, Zheng-Wen; Qin, Dong

    2014-03-12

    We report a strategy to complement the galvanic replacement reaction between Ag nanocubes and HAuCl4 with co-reduction by ascorbic acid (AA) for the formation of Ag-Au hollow nanostructures with greatly enhanced SERS activity. Specifically, in the early stage of synthesis, the Ag nanocubes are sharpened at corners and edges because of the selective deposition of Au and Ag atoms at these sites. In the following steps, the pure Ag in the nanocubes is constantly converted into Ag(+) ions to generate voids owing to the galvanic reaction with HAuCl4, but these released Ag(+) ions are immediately reduced back to Ag atoms and are co-deposited with Au atoms onto the nanocube templates. We observe distinctive SERS properties for the Ag-Au hollow nanostructures at visible and near-infrared excitation wavelengths. When plasmon damping is eliminated by using an excitation wavelength of 785 nm, the SERS activity of the Ag-Au hollow nanostructures is 15- and 33-fold stronger than those of the original Ag nanocubes and the Ag-Au nanocages prepared by galvanic replacement without co-reduction, respectively. Additionally, Ag-Au hollow nanostructures embrace considerably improved stability in an oxidizing environment such as aqueous H2O2 solution. Collectively, our work suggests that the Ag-Au hollow nanostructures will find applications in SERS detection and imaging.

  14. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    International Nuclear Information System (INIS)

    Zhi-Guo, Xie; Yong-Hua, Lu; Pei, Wang; Kai-Qun, Lin; Jie, Yan; Hai, Ming

    2008-01-01

    A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA) molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area

  15. Importance of uncharged polar residues and proline in the proximal two-thirds (Pro107–Ser128 of the highly conserved region of mouse ileal Na+-dependent bile acid transporter, Slc10a2, in transport activity and cellular expression

    Directory of Open Access Journals (Sweden)

    Saeki Tohru

    2013-02-01

    Full Text Available Abstract Background SLC10A2-mediated reabsorption of bile acids at the distal end of the ileum is the first step in enterohepatic circulation. Because bile acids act not only as detergents but also as signaling molecules in lipid metabolism and energy production, SLC10A2 is important as the key transporter for understanding the in vivo kinetics of bile acids. SLC10A family members and the homologous genes of various species share a highly conserved region corresponding to Gly104–Pro142 of SLC10A2. The functional importance of this region has not been fully elucidated. Results To elucidate the functional importance of this region, we previously performed mutational analysis of the uncharged polar residues and proline in the distal one-third (Thr130–Pro142 of the highly conserved region in mouse Slc10a2. In this study, proline and uncharged polar residues in the remaining two-thirds of this region in mouse Slc10a2 were subjected to mutational analysis, and taurocholic acid uptake and cell surface localization were examined. Cell surface localization of Slc10a2 is necessary for bile acid absorption. Mutants in which Asp or Leu were substituted for Pro107 (P107N or P107L were abundantly expressed, but their cell surface localization was impaired. The S126A mutant was completely impaired in cellular expression. The T110A and S128A mutants exhibited remarkably enhanced membrane expression. The S112A mutant was properly expressed at the cell surface but transport activity was completely lost. Replacement of Tyr117 with various amino acids resulted in reduced transport activity. The degree of reduction roughly depended on the van der Waals volume of the side chains. Conclusions The functional importance of proline and uncharged polar residues in the highly conserved region of mouse Slc10a2 was determined. This information will contribute to the design of bile acid-conjugated prodrugs for efficient drug delivery or SLC10A2 inhibitors for

  16. Surface modification of nanoporous alumina layers by deposition of Ag nanoparticles. Effect of alumina pore diameter on the morphology of silver deposit and its influence on SERS activity

    Science.gov (United States)

    Pisarek, Marcin; Nowakowski, Robert; Kudelski, Andrzej; Holdynski, Marcin; Roguska, Agata; Janik-Czachor, Maria; Kurowska-Tabor, Elżbieta; Sulka, Grzegorz D.

    2015-12-01

    Self-organized Al2O3 nanoporous/nanotubular (Al2O3-NP) oxide layers decorated with silver nanoparticles (Ag-NPs) exhibiting specific properties may serve as attractive SERS substrates for investigating the interactions between an adsorbate and adsorbent, or as stable platforms for detecting various organic compounds. This article presents the influence of the size of the alumina nanopores with a deposit of silver nanoparticles obtained by the magnetron sputtering technique on the morphology of silver film. Moreover, the effect of pore diameter on the intensity of SERS spectra in Ag-NPs/Al2O3-NP/Al composites has also been estimated. For such investigations we used pyridine as a probe molecule, since it has a large cross-section for Raman scattering. To characterize the morphology of the composite oxide layer Ag-NPs/Al2O3-NP/Al, before and after deposition of Ag-NPs by PVD methods (Physical Vapor Deposition), we used scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface analytical technique of surface-enhanced Raman spectroscopy (SERS) was used to investigate the surface activity of the composite. The results obtained show that, for a carefully controlled amount of Ag (0.020 mg/cm2 - deposited on the top of alumina nanopores whose average size varies from ∼86 nm up to ∼320 nm) in the composites investigated, pore size significantly affects SERS enhancement. We obtained distinctly higher intensities of SERS spectra for substrates with an Ag-NPs deposit having a larger diameter of the alumina nanopores. AFM results suggest that both the lateral and perpendicular distribution of Ag-NPs within and on the top of the largest pores is responsible for the highest SERS activity of the resulting Ag-NPs/Al2O3-NP/Al composite layer, since it produces a variety of cavities and slits which function as resonators for the adsorbed molecules. The Ag-NPs/MeOx-NP/Me composite layers obtained ensure a good reproducibility of the SERS measurements.

  17. for SERS and Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Xue Chen

    2011-01-01

    Full Text Available ZnS/Si nanocables were synthesized via a simple two-step thermal evaporation method. The shape and diameter of the ZnS/Si nanocables can be controlled by adjusting the morphologies of the ZnS nanostructures (nanowire or nanoribbon obtained in the first step and the deposition time of the Si shell in the second step, respectively. Furthermore, we obtained polycrystalline Si nanotubes with different shapes and diameters by etching away the inner ZnS core. The as-prepared Si nanotubes were employed as SERS-active substrates, which exhibited a high sensitivity for the detection of R6G. The Si nanotubes also showed effective photocatalytic activity on the decomposition of R6G under the irradiation of visible light.

  18. Galvanic replacement-free deposition of Au on Ag for core-shell nanocubes with enhanced chemical stability and SERS activity.

    Science.gov (United States)

    Yang, Yin; Liu, Jingyue; Fu, Zheng-Wen; Qin, Dong

    2014-06-11

    We report a robust synthesis of Ag@Au core-shell nanocubes by directly depositing Au atoms on the surfaces of Ag nanocubes as conformal, ultrathin shells. Our success relies on the introduction of a strong reducing agent to compete with and thereby block the galvanic replacement between Ag and HAuCl4. An ultrathin Au shell of 0.6 nm thick was able to protect the Ag in the core in an oxidative environment. Significantly, the core-shell nanocubes exhibited surface plasmonic properties essentially identical to those of the original Ag nanocubes, while the SERS activity showed a 5.4-fold further enhancement owing to an improvement in chemical enhancement. The combination of excellent SERS activity and chemical stability may enable a variety of new applications.

  19. High Surface-Enhanced Raman Scattering (SERS) Amplification Factor Obtained with Silver Printed Circuit Boards and the Influence of Phenolic Resins for the Characterization of the Pesticide Thiram.

    Science.gov (United States)

    Silva de Almeida, Francylaine; Bussler, Larissa; Marcio Lima, Sandro; Fiorucci, Antonio Rogério; da Cunha Andrade, Luis Humberto

    2016-07-01

    In this work, low-cost substrates with rough silver surfaces were prepared from commercial copper foil-covered phenolic board (CPB) and an aqueous solution of AgNO3, and were used for surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) measurements. A maximum SERS amplification factor of 1.2 × 10(7) was obtained for Rhodamine 6G (R6G), and use of the CPB resulted in a detection limit for Thiram pesticide of 0.5 µmol L(-1) The minimum detection level was limited by residual traces of phenolic groups that originated from the substrate resin, which became solubilized in the aqueous Ag(+) solution. It was found that the bands corresponding to the impurities had less influence in the Thiram analysis, which could be explained by the high affinity of sulfur for Ag surfaces. The influence of impurities in the SERS analyses therefore depended on the linkage between the rough silver surface and the analyte. The findings demonstrated the ease and effectiveness of using CPB to prepare a nanostructured surface for SERS. © The Author(s) 2016.

  20. Replacement of Ser108 in Plasmodium falciparum enolase results in weak Mg(II) binding: role of a parasite-specific pentapeptide insert in stabilizing the active conformation of the enzyme.

    Science.gov (United States)

    Dutta, Sneha; Mukherjee, Debanjan; Jarori, Gotam K

    2015-06-01

    A distinct structural feature of Plasmodium falciparum enolase (Pfeno) is the presence of a five amino acid insert -104EWGWS108- that is not found in host enolases. Its conservation among apicomplexan enolases has raised the possibility of its involvement in some important physiological function(s). Deletion of this sequence is known to lower k(cat)/K(m), increase K(a) for Mg(II) and convert dimer into monomers (Vora HK, Shaik FR, Pal-Bhowmick I, Mout R & Jarori GK (2009) Arch Biochem Biophys 485, 128-138). These authors also raised the possibility of the formation of an H-bond between Ser108 and Leu49 that could stabilize the apo-Pfeno in an active closed conformation that has high affinity for Mg(II). Here, we examined the effect of replacement of Ser108 with Gly/Ala/Thr on enzyme activity, Mg(II) binding affinity, conformational states and oligomeric structure and compared it with native recombinant Pfeno. The results obtained support the view that Ser108 is likely to be involved in the formation of certain crucial H-bonds with Leu49. The presence of these interactions can stabilize apo-Pfeno in an active closed conformation similar to that of Mg(II) bound yeast enolase. As predicted, S108G/A-Pfeno variants (where Ser108-Leu49 H-bonds are likely to be disrupted) were found to exist in an open conformation and had low affinity for Mg(II). They also required Mg(II) induced conformational changes to acquire the active closed conformational state essential for catalysis. The possible physiological relevance of apo-Pfeno being in such an active state is discussed. © 2015 FEBS.

  1. Microwave assisted facile synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite and their application as active SERS substrate

    International Nuclear Information System (INIS)

    Wadhwa, Heena; Kumar, Devender; Mahendia, Suman; Kumar, Shyam

    2017-01-01

    The present paper represents the facile and rapid synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite with the help of microwave irradiation. The graphene oxide (GO) solution has been prepared in bulk using Hummer's method followed by microwave assisted in-situ reduction of GO and silver nitrate (AgNO_3) by hydrazine hydrate in a short spam of 5 min. The prepared nanocomposite has been characterized using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) Scanning Electron Microscopy (SEM) and UV–Visible spectroscopy. TEM analysis shows that Ag nanoparticles with average size 32 nm are uniformly entangled with in RGO layers. The UV–Visible absorption spectrum of nanocomposite depicts the reduction of GO to RGO along with the formation of Ag nanoparticles with the presence of characteristic surface Plasmon resonance (SPR) peak of Ag nanoparticles at 422 nm. The performance of prepared nanocomposite has been tested as the active Surface Enhanced Raman Scattering (SERS) substrate for Rhodamine 6G with detection limit 0.1 μM. - Highlights: • The RGO and RGO-Ag nanocomposite were synthesized with microwave irradiation. • Ag nanoparticles of average size 32 nm are uniformly entangled within RGO layers. • RGO itself is a florescence quencher with SERS detection limit 1 μM for R6G. • RGO-Ag nanocomposite show good SERS activity for R6G with detection limit 0.1 μM.

  2. Microwave assisted facile synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite and their application as active SERS substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wadhwa, Heena, E-mail: heenawadhwa1988@gmail.com; Kumar, Devender, E-mail: devkumsaroha@kuk.ac.in; Mahendia, Suman, E-mail: mahendia@gmail.com; Kumar, Shyam, E-mail: profshyam@gmail.com

    2017-06-15

    The present paper represents the facile and rapid synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite with the help of microwave irradiation. The graphene oxide (GO) solution has been prepared in bulk using Hummer's method followed by microwave assisted in-situ reduction of GO and silver nitrate (AgNO{sub 3}) by hydrazine hydrate in a short spam of 5 min. The prepared nanocomposite has been characterized using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) Scanning Electron Microscopy (SEM) and UV–Visible spectroscopy. TEM analysis shows that Ag nanoparticles with average size 32 nm are uniformly entangled with in RGO layers. The UV–Visible absorption spectrum of nanocomposite depicts the reduction of GO to RGO along with the formation of Ag nanoparticles with the presence of characteristic surface Plasmon resonance (SPR) peak of Ag nanoparticles at 422 nm. The performance of prepared nanocomposite has been tested as the active Surface Enhanced Raman Scattering (SERS) substrate for Rhodamine 6G with detection limit 0.1 μM. - Highlights: • The RGO and RGO-Ag nanocomposite were synthesized with microwave irradiation. • Ag nanoparticles of average size 32 nm are uniformly entangled within RGO layers. • RGO itself is a florescence quencher with SERS detection limit 1 μM for R6G. • RGO-Ag nanocomposite show good SERS activity for R6G with detection limit 0.1 μM.

  3. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    Energy Technology Data Exchange (ETDEWEB)

    Boca, Sanda C; Astilean, Simion, E-mail: sboca@phys.ubbcluj.ro, E-mail: sastil@phys.ubbcluj.ro [Nanobiophotonics Center, Institute for Interdisciplinary Research in Nanobioscience, Babes-Bolyai University, Treboniu Laurian Street 42, 400271 Cluj-Napoca (Romania)

    2010-06-11

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 deg. C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  4. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    Science.gov (United States)

    Boca, Sanda C.; Astilean, Simion

    2010-06-01

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 °C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  5. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    International Nuclear Information System (INIS)

    Boca, Sanda C; Astilean, Simion

    2010-01-01

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 deg. C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  6. SERS-active Ag, Au and Ag–Au alloy nanoparticles obtained by laser ablation in liquids for sensing methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Olea-Mejía, Oscar, E-mail: oleaoscar@yahoo.com.mx [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Fernández-Mondragón, Mariana; Rodríguez-de la Concha, Gabriela [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Camacho-López, Marco [Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Universidad Autónoma del Estado de México, Km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50925, México (Mexico)

    2015-09-01

    Highlights: • We synthesized Ag/Au nanoparticles by laser ablation in liquids. • We characterized such particles by UV–vis, TEM and EDS/STEM. • The SERS effect was studied for the obtained nanoparticles. • Pure silver nanoparticles showed the highest SERS signals. • We can sense methylene blue at a concentration of 10{sup −10} mole/L. - Abstract: We have synthesized Ag–Au nanoparticles by laser ablation in liquids using five different targets: 100% Ag, 80%Ag/20%Au, 50%Ag/50%Au, 20%Ag/80%Au and 100% Au (weight percentages). We used ethanol and methylene blue solutions in ethanol as the liquid media. The nanoparticles were mostly spherical with diameters 15, 19, 18, 23 and 11 nm, respectively. When alloyed targets were used, the resulting nanoparticles were completely alloyed forming solid solutions as evidenced by UV–vis Spectroscopy and Scanning Transmission Electron Microscopy. The obtained nanoparticles were employed to study the SERS effect of the methylene blue molecule. All the samples showed good SERS activity, however the ones composed of pure silver showed the greatest Raman signal enhancement. Finally, pure Ag nanoparticles were used for sensing methylene blue at different concentrations. While almost no signal can be discerned from the Raman spectrum when no particles are used at a concentration of methylene blue of 1 × 10{sup −2} M (∼3000 ppm), when Ag nanoparticles are used one can observe the characteristic peak of the molecule at concentrations as low as 1 × 10{sup −10} M (∼3 × 10{sup −5} ppm)

  7. Phosphorylation of protein kinase C sites Ser42/44 decreases Ca2+-sensitivity and blunts enhanced length-dependent activation in response to protein kinase A in human cardiomyocytes

    NARCIS (Netherlands)

    Wijnker, P.J.M.; Sequeira Oliveira, V.; Witjas-Paalberends, E.R.; Foster, D.B.; dos Remedios, C.G.; Murphy, A.M.; Stienen, G.J.M.; van der Velden, J.

    2014-01-01

    Protein kinase C (PKC)-mediated phosphorylation of troponin I (cTnI) at Ser42/44 is increased in heart failure. While studies in rodents demonstrated that PKC-mediated Ser42/44 phosphorylation decreases maximal force and ATPase activity, PKC incubation of human cardiomyocytes did not affect maximal

  8. Stamping SERS for creatinine sensing

    Science.gov (United States)

    Li, Ming; Du, Yong; Zhao, Fusheng; Zeng, Jianbo; Santos, Greggy M.; Mohan, Chandra; Shih, Wei-Chuan

    2015-03-01

    Urine can be obtained easily, readily and non-invasively. The analysis of urine can provide metabolic information of the body and the condition of renal function. Creatinine is one of the major components of human urine associated with muscle metabolism. Since the content of creatinine excreted into urine is relatively constant, it is used as an internal standard to normalize water variations. Moreover, the detection of creatinine concentration in urine is important for the renal clearance test, which can monitor the filtration function of kidney and health status. In more details, kidney failure can be imminent when the creatinine concentration in urine is high. A simple device and protocol for creatinine sensing in urine samples can be valuable for point-of-care applications. We reported quantitative analysis of creatinine in urine samples by using stamping surface enhanced Raman scattering (S-SERS) technique with nanoporous gold disk (NPGD) based SERS substrate. S-SERS technique enables label-free and multiplexed molecular sensing under dry condition, while NPGD provides a robust, controllable, and high-sensitivity SERS substrate. The performance of S-SERS with NGPDs is evaluated by the detection and quantification of pure creatinine and creatinine in artificial urine within physiologically relevant concentration ranges.

  9. Phosphorylation of rat kidney Na-K pump at Ser938 is required for rapid angiotensin II-dependent stimulation of activity and trafficking in proximal tubule cells.

    Science.gov (United States)

    Massey, Katherine J; Li, Quanwen; Rossi, Noreen F; Keezer, Susan M; Mattingly, Raymond R; Yingst, Douglas R

    2016-02-01

    How angiotensin (ANG) II acutely stimulates the Na-K pump in proximal tubules is only partially understood, limiting insight into how ANG II increases blood pressure. First, we tested whether ANG II increases the number of pumps in plasma membranes of native rat proximal tubules under conditions of rapid activation. We found that exposure to 100 pM ANG II for 2 min, which was previously shown to increase affinity of the Na-K pump for Na and stimulate activity threefold, increased the amount of the Na-K pump in plasma membranes of native tubules by 33%. Second, we tested whether previously observed increases in phosphorylation of the Na-K pump at Ser(938) were part of the stimulatory mechanism. These experiments were carried out in opossum kidney cells, cultured proximal tubules stably coexpressing the ANG type 1 (AT1) receptor, and either wild-type or a S938A mutant of rat kidney Na-K pump under conditions found by others to stimulate activity. We found that 10 min of incubation in 10 pM ANG II stimulated activity of wild-type pumps from 2.3 to 3.5 nmol K · mg protein(-1) · min(-1) and increased the amount of the pump in the plasma membrane by 80% but had no effect on cells expressing the S938A mutant. We conclude that acute stimulation of Na-K pump activity in native rat proximal tubules includes increased trafficking to the plasma membrane and that phosphorylation at Ser(938) is part of the mechanism by which ANG II directly stimulates activity and trafficking of the rat kidney Na-K pump in opossum kidney cells.

  10. Optimizing silver-capped silicon nanopillars to simultaneously realize macroscopic, practical-level SERS signal reproducibility and high enhancement at low costs

    DEFF Research Database (Denmark)

    Wu, Kaiyu; Rindzevicius, Tomas; Schmidt, Michael Stenbæk

    2017-01-01

    and show that the improved structures exhibit unrivalled macroscale SERS uniformities (RSD: ∼2.5% in millimeter scale, ∼7% in wafer scale) and reproducibility (RSD: ∼1.5% across 3 wafers), while at the same time exhibiting a very large average SERS enhancement factor of >108. The obtained SERS uniformity...

  11. Surface enhanced Raman scattering (SERS) fabrics for trace analysis

    International Nuclear Information System (INIS)

    Liu, Jun; Zhou, Ji; Tang, Bin; Zeng, Tian; Li, Yaling; Li, Jingliang; Ye, Yong; Wang, Xungai

    2016-01-01

    Highlights: • Gold nanoparticles are in-situ synthesized on silk fabrics by heating. • Flexible silk fabrics with gold nanoparticles are used for surface-enhanced Raman scattering (SERS). • SERS activities of silk fabrics with different gold contents are investigated. - Abstract: Flexible SERS active substrates were prepared by modification of silk fabrics with gold nanoparticles. Gold nanoparticles were in-situ synthesized after heating the silk fabrics immersed in gold ion solution. Localized surface plasmon resonance (LSPR) properties of the treated silk fabrics varied as the concentration of gold ions changed, in relation to the morphologies of gold nanoparticles on silk. In addition, X-ray diffraction (XRD) was used to observe the structure of the gold nanoparticle treated silk fabrics. The SERS enhancement effect of the silk fabrics treated with gold nanoparticles was evaluated by collecting Raman signals of different concentrations of p-aminothiophenol (PATP), 4-mercaptopyridine (4-MPy) and crystal violet (CV) solutions. The results demonstrate that the silk fabrics corresponding to 0.3 and 0.4 mM of gold ions possess high SERS activity compared to the other treated fabrics. It is suggested that both the gold content and morphologies of gold nanoparticles dominate the SERS effect of the treated silk fabrics.

  12. Surface enhanced Raman scattering (SERS) fabrics for trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Zhou, Ji [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Tang, Bin, E-mail: bin.tang@deakin.edu.au [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia); Zeng, Tian; Li, Yaling [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Li, Jingliang [Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia); Ye, Yong, E-mail: yeyong@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Wang, Xungai [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia)

    2016-11-15

    Highlights: • Gold nanoparticles are in-situ synthesized on silk fabrics by heating. • Flexible silk fabrics with gold nanoparticles are used for surface-enhanced Raman scattering (SERS). • SERS activities of silk fabrics with different gold contents are investigated. - Abstract: Flexible SERS active substrates were prepared by modification of silk fabrics with gold nanoparticles. Gold nanoparticles were in-situ synthesized after heating the silk fabrics immersed in gold ion solution. Localized surface plasmon resonance (LSPR) properties of the treated silk fabrics varied as the concentration of gold ions changed, in relation to the morphologies of gold nanoparticles on silk. In addition, X-ray diffraction (XRD) was used to observe the structure of the gold nanoparticle treated silk fabrics. The SERS enhancement effect of the silk fabrics treated with gold nanoparticles was evaluated by collecting Raman signals of different concentrations of p-aminothiophenol (PATP), 4-mercaptopyridine (4-MPy) and crystal violet (CV) solutions. The results demonstrate that the silk fabrics corresponding to 0.3 and 0.4 mM of gold ions possess high SERS activity compared to the other treated fabrics. It is suggested that both the gold content and morphologies of gold nanoparticles dominate the SERS effect of the treated silk fabrics.

  13. Phosphorylation of Ser1928 mediates the enhanced activity of the L-type Ca2+ channel Cav1.2 by the β2-adrenergic receptor in neurons.

    Science.gov (United States)

    Qian, Hai; Patriarchi, Tommaso; Price, Jennifer L; Matt, Lucas; Lee, Boram; Nieves-Cintrón, Madeline; Buonarati, Olivia R; Chowdhury, Dhrubajyoti; Nanou, Evanthia; Nystoriak, Matthew A; Catterall, William A; Poomvanicha, Montatip; Hofmann, Franz; Navedo, Manuel F; Hell, Johannes W

    2017-01-24

    The L-type Ca 2+ channel Ca v 1.2 controls multiple functions throughout the body including heart rate and neuronal excitability. It is a key mediator of fight-or-flight stress responses triggered by a signaling pathway involving β-adrenergic receptors (βARs), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA). PKA readily phosphorylates Ser 1928 in Ca v 1.2 in vitro and in vivo, including in rodents and humans. However, S1928A knock-in (KI) mice have normal PKA-mediated L-type channel regulation in the heart, indicating that Ser 1928 is not required for regulation of cardiac Ca v 1.2 by PKA in this tissue. We report that augmentation of L-type currents by PKA in neurons was absent in S1928A KI mice. Furthermore, S1928A KI mice failed to induce long-term potentiation in response to prolonged theta-tetanus (PTT-LTP), a form of synaptic plasticity that requires Ca v 1.2 and enhancement of its activity by the β 2 -adrenergic receptor (β 2 AR)-cAMP-PKA cascade. Thus, there is an unexpected dichotomy in the control of Ca v 1.2 by PKA in cardiomyocytes and hippocampal neurons. Copyright © 2017, American Association for the Advancement of Science.

  14. Superhydrophobic Ag nanostructures on polyaniline membranes with strong SERS enhancement.

    Science.gov (United States)

    Liu, Weiyu; Miao, Peng; Xiong, Lu; Du, Yunchen; Han, Xijiang; Xu, Ping

    2014-11-07

    We demonstrate here a facile fabrication of n-dodecyl mercaptan-modified superhydrophobic Ag nanostructures on polyaniline membranes for molecular detection based on SERS technique, which combines the superhydrophobic condensation effect and the high enhancement factor. It is calculated that the as-fabricated superhydrophobic substrate can exhibit a 21-fold stronger molecular condensation, and thus further amplifies the SERS signal to achieve more sensitive detection. The detection limit of the target molecule, methylene blue (MB), on this superhydrophobic substrate can be 1 order of magnitude higher than that on the hydrophilic substrate. With high reproducibility, the feasibility of using this SERS-active superhydrophobic substrate for quantitative molecular detection is explored. A partial least squares (PLS) model was established for the quantification of MB by SERS, with correlation coefficient R(2) = 95.1% and root-mean-squared error of prediction (RMSEP) = 0.226. We believe this superhydrophobic SERS substrate can be widely used in trace analysis due to its facile fabrication, high signal reproducibility and promising SERS performance.

  15. Highly reproducible surface-enhanced Raman scattering-active Au nanostructures prepared by simple electrodeposition: origin of surface-enhanced Raman scattering activity and applications as electrochemical substrates.

    Science.gov (United States)

    Choi, Suhee; Ahn, Miri; Kim, Jongwon

    2013-05-24

    The fabrication of effective surface-enhanced Raman scattering (SERS) substrates has been the subject of intensive research because of their useful applications. In this paper, dendritic gold (Au) rod (DAR) structures prepared by simple one-step electrodeposition in a short time were examined as an effective SERS-active substrate. The SERS activity of the DAR surfaces was compared to that of other nanostructured Au surfaces with different morphologies, and its dependence on the structural variation of DAR structures was examined. These comparisonal investigations revealed that highly faceted sharp edge sites present on the DAR surfaces play a critical role in inducing a high SERS activity. The SERS enhancement factor was estimated to be greater than 10(5), and the detection limit of rhodamine 6G at DAR surfaces was 10(-8)M. The DAR surfaces exhibit excellent spot-to-spot and substrate-to-substrate SERS enhancement reproducibility, and their long-term stability is very good. It was also demonstrated that the DAR surfaces can be effectively utilized in electrochemical SERS systems, wherein a reversible SERS behavior was obtained during the cycling to cathodic potential regions. Considering the straightforward preparation of DAR substrates and the clean nature of SERS-active Au surfaces prepared in the absence of additives, we expect that DAR surfaces can be used as cost-effective SERS substrates in analytical and electrochemical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Functional human sperm capacitation requires both bicarbonate-dependent PKA activation and down-regulation of Ser/Thr phosphatases by Src family kinases.

    Science.gov (United States)

    Battistone, M A; Da Ros, V G; Salicioni, A M; Navarrete, F A; Krapf, D; Visconti, P E; Cuasnicú, P S

    2013-09-01

    In all mammalian species studied so far, sperm capacitation correlates with an increase in protein tyrosine (Tyr) phosphorylation mediated by a bicarbonate-dependent cAMP/protein kinase A (PKA) pathway. Recent studies in mice revealed, however, that a Src family kinase (SFK)-induced inactivation of serine/threonine (Ser/Thr) phosphatases is also involved in the signaling pathways leading to Tyr phosphorylation. In view of these observations and with the aim of getting a better understanding of the signaling pathways involved in human sperm capacitation, in the present work we investigated the involvement of both the cAMP/PKA and SFK/phosphatase pathways in relation to the capacitation state of the cells. For this purpose, different signaling events and sperm functional parameters were analyzed as a function of capacitation time. Results revealed a very early bicarbonate-dependent activation of PKA indicated by the rapid (1 min) increase in both phospho-PKA substrates and cAMP levels (P < 0.05). However, a complete pattern of Tyr phosphorylation was detected only after 6-h incubation at which time sperm exhibited the ability to undergo the acrosome reaction (AR) and to penetrate zona-free hamster oocytes. Sperm capacitated in the presence of the SFK inhibitor SKI606 showed a decrease in both PKA substrate and Tyr phosphorylation levels, which was overcome by exposure of sperm to the Ser/Thr phosphatase inhibitor okadaic acid (OA). However, OA was unable to induce phosphorylation when sperm were incubated under PKA-inhibitory conditions (i.e. in the absence of bicarbonate or in the presence of PKA inhibitor). Moreover, the increase in PKA activity by exposure to a cAMP analog and a phosphodiesterase inhibitor did not overcome the inhibition produced by SKI606. Whereas the presence of SKI606 during capacitation produced a negative effect (P < 0.05) on sperm motility, progesterone-induced AR and fertilizing ability, none of these inhibitions were observed when sperm

  17. Highly Sensitive and Selective In-Situ SERS Detection of Pb(2+), Hg(2+), and Cd(2+) Using Nanoporous Membrane Functionalized with CNTs.

    Science.gov (United States)

    Shaban, Mohamed; Galaly, A R

    2016-05-04

    Porous Anodic Alumina (PAA) membrane was functionalized with CoFe2O4 nanoparticles and used as a substrate for the growing of very long helical-structured Carbon Nanotubes (CNTs) with a diameter less than 20 nm. The structures and morphologies of the fabricated nanostructures were characterized by field emission- scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), and Raman spectroscopy. By uploading the CNTs on PAA, the characteristic Raman peaks of CNTs and PAA showed 4 and 3 times enhancement, respectively, which leads to more sensitive Surface-Enhanced Raman Spectroscopy (SERS) substrates. For comparison, PAA and CNTs/PAA arrays were used as SERS substrates for the detection of Hg(2+), Cd(2+), and Pb(2+). The proposed sensor demonstrated high sensitivity and selectivity between these heavy metal ions. CNTs/PAA sensor showed excellent selectivity toward Pb(2+) over other metal ions, where the enhancement factor is decreased from ~17 for Pb(2+) to ~12 for Hg(2+) and to ~4 for Cd(2+). Therefore, the proposed CNTs/PAA sensor can be used as a powerful tool for the determination of heavy metal ions in aqueous solutions.

  18. Highly Sensitive and Selective In-Situ SERS Detection of Pb2+, Hg2+, and Cd2+ Using Nanoporous Membrane Functionalized with CNTs

    Science.gov (United States)

    Shaban, Mohamed; Galaly, A. R.

    2016-01-01

    Porous Anodic Alumina (PAA) membrane was functionalized with CoFe2O4 nanoparticles and used as a substrate for the growing of very long helical-structured Carbon Nanotubes (CNTs) with a diameter less than 20 nm. The structures and morphologies of the fabricated nanostructures were characterized by field emission- scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), and Raman spectroscopy. By uploading the CNTs on PAA, the characteristic Raman peaks of CNTs and PAA showed 4 and 3 times enhancement, respectively, which leads to more sensitive Surface-Enhanced Raman Spectroscopy (SERS) substrates. For comparison, PAA and CNTs/PAA arrays were used as SERS substrates for the detection of Hg2+, Cd2+, and Pb2+. The proposed sensor demonstrated high sensitivity and selectivity between these heavy metal ions. CNTs/PAA sensor showed excellent selectivity toward Pb2+ over other metal ions, where the enhancement factor is decreased from ~17 for Pb2+ to ~12 for Hg2+ and to ~4 for Cd2+. Therefore, the proposed CNTs/PAA sensor can be used as a powerful tool for the determination of heavy metal ions in aqueous solutions. PMID:27143512

  19. A high-yield, one-step synthesis of surfactant-free gold nanostars and numerical study for single-molecule SERS application

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, S.; Ringane, A. B.; Arya, A.; Das, G. M.; Dantham, V. R., E-mail: dantham@iitp.ac.in; Laha, R. [Indian Institute of Technology Patna, Department of Physics (India); Hussian, S. [Indian Institute of Technology Patna, Department of Chemistry (India)

    2016-08-15

    We report a high-yield synthesis of star-shaped gold nanostructures in one step, using a new surfactant-free wet chemistry method. Compared to the existing reports, these nanostars were found to have longer and sharper spikes anchored uniformly on the surface of the spherical core, allowing at least a few hot spots irrespective of the incident light polarization. The average experimental values of core radius and spike length were found to be 88.5 and 72 nm, respectively. Using these values in numerical simulations, the local electric field enhancement (η) and localized surface plasmon resonance (LSPR) spectrum were obtained. Moreover, the single-molecule surface-enhanced Raman scattering (SERS) enhancement factor was found to vary from 10{sup 10} to 10{sup 13} depending on the excitation wavelengths. Our theoretical calculations suggest that these nanostructures can be used to fabricate efficient SERS-based biosensors for the detection of single molecules in real time and for predicting structural information of single molecules.

  20. High activity waste disposal

    International Nuclear Information System (INIS)

    Gaul, W.C.

    1990-01-01

    Chem-Nuclear Environmental Services (CNES) has developed a container that is capable of containing high activity waste and can be shipped as a regular DOT Type A shipment. By making the container special form the amount of activity that can be transported in a Type A shipment is greatly enhanced. Special form material presents an extra degree of protection to the environment by requiring the package to be destroyed to get access to the radioactive material and must undergo specific testing requirements, whereas normal form material can allow access to the radioactive material. With the special form container up to 10 caries of radium can be transported in a single package. This paper will describe the considerations that were taken to develop these products

  1. FDTD simulation study of size/gap and substrate-dependent SERS activity study of Au@SiO2 nanoparticles

    International Nuclear Information System (INIS)

    Yang Jing-Liang; Li Ruo-Ping; Han Jun-He; Huang Ming-Ju

    2016-01-01

    We use Au@SiO 2 nanoparticles (NPs) to systematically and comprehensively study the relationship between nanostructure and activity for surface-enhanced Raman scattering. Calculation simulation using the finite different time domain method verifies the experiment results and further reveals that the particle size and the distance between the NPs play vital roles in the surface-enhanced Raman scattering (SERS). Furthermore, in order to better simulate the real experiment, a Au@SiO 2 nanosphere dimer is placed on the silicon substrate and Au substrate, separately. The simulation results show that the large EM field coupling is due to the “hot spots” transferred from the NP–NP gaps to NP–surface of metal gaps, meanwhile, more “hot spots” occur. We also find that the signal intensity strongly depends on the position of the probe molecule. This work provides a better understanding of EM field enhancement. (paper)

  2. Reduction of silver nanoparticles onto graphene oxide nanosheets with N,N-dimethylformamide and SERS activities of GO/Ag composites

    International Nuclear Information System (INIS)

    Yang Yingkui; He Chengen; He Wenjie; Yu Linjuan; Peng Rengui; Xie Xiaolin; Wang Xianbao; Mai Yiuwing

    2011-01-01

    Silver nanoparticles (Ag NPs) have been homogeneously deposited onto graphene oxide (GO) nanosheets by an optimal method, in which N,N-dimethylformamide (DMF) as a co-dispersant of GO and reductant of sliver ions is added to an aqueous suspension of GO and AgNO 3 . GO nanosheets are uniformly covered by Ag NPs with a narrow size distribution and inter-particle gap. Raman signals of GO are greatly enhanced after deposition owing to the charge transfer interaction of GO with Ag NPs. The GO/Ag composite can be further utilized as an effective surface-enhanced Raman scattering (SERS) active substrate. Several new Raman bands and frequency shifts are clearly observed in using 4-aminothiophenol (4-ATP) as a Raman probe on GO/Ag compared to the normal Raman spectrum of solid 4-ATP. The Raman enhancement arises from a major electromagnetic effect and a minor chemical effect.

  3. Electrochemical and in-situ Surface-Enhanced Raman Spectroscopic (SERS) study of passive films formed on low-carbon steel in highly alkaline environments

    Science.gov (United States)

    Mancio, Mauricio

    In reinforced concrete, a passive layer forms because of the alkaline conditions in the pores of the cement paste, where large concentrations of hydroxides create a solution with pH typically between 12 and 14. The corrosion resistance of the material depends on the characteristics and integrity of the passive film; however, currently very limited information is available about the passive films formed on carbon steel under such conditions. This work presents an electrochemical and in-situ Surface-Enhanced Raman Spectroscopic (SERS) study of passive films formed on low-carbon steel in highly alkaline environments. More specifically, the study focuses on the characterization of the films formed on ASTM A36 steel reinforcing bar exposed to aqueous solutions that aim to reproduce the chemistry of the environment typically found within the cement paste. Electrochemical techniques such as cyclic potentiodynamic polarization curves, galvanostatic cathodic polarization and linear polarization resistance were employed, in addition to in-situ Surface Enhanced Raman Spectroscopy (SERS). The experimental setup was built in a way that SERS experiments could be performed simultaneously with potentiodynamic polarization curves, enabling a detailed analysis of the formation and reduction of the surface films as a function of applied potential. Three solutions with different pH levels were used for the polarization and SERS experiments, namely 0.55M KOH + 0.16M NaOH ([OH-]=0.71), 0.08M KOH + 0.02M NaOH ([OH-]=0.10) and 0.008M KOH + 0.002M NaOH ([OH-]=0.01). Additional NaOH solutions in which the pH was varied from 13 to 9 and the ionic strength from 10 -5 to 10-1 were prepared for a pilot study using linear polarization resistance. Results show that the features observed in the cyclic potentiodynamic polarization curves correlated well with the potential arrests observed in the GCP plots as well as with the changes observed in the SERS spectra, providing valuable information about

  4. SERS Engineering Collaboration

    Science.gov (United States)

    2012-06-01

    laser beam. In the second approach, a pulsed laser was used to texture a silicon wafer to form sharp features. Silver was evaporated onto the wafer...orders of magnitude larger than that measured on a gold nanoparticle array on a glass substrate. The largest SERS enhancement for a silver device was...surface plasmons," Yizhuo Chu and Kenneth B. Crozier, Optics Letters vol. 34, 244 (2009) K3. "Gold nanorings as substrates for surface-enhanced Raman

  5. Review on SERS of Bacteria

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-11-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

  6. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

    Science.gov (United States)

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-04-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

  7. SERS-based application in food analytics (Conference Presentation)

    Science.gov (United States)

    Cialla-May, Dana; Radu, Andreea; Jahn, Martin; Weber, Karina; Popp, Jürgen

    2017-02-01

    To establish detection schemes in life science applications, specific and sensitive methods allowing for fast detection times are required. Due to the interaction of molecules with strong electromagnetic fields excited at metallic nanostructures, the molecular fingerprint specific Raman spectrum is increased by several orders of magnitude. This effect is described as surface-enhanced Raman spectroscopy (SERS) and became a very powerful analytical tool in many fields of application. Within this presentation, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer. To do so, the food colorant Sudan III, an indirect carcinogen substance found in chili powder, palm oil or spice mixtures, is detected quantitatively in the background of the competitor riboflavin as well as paprika powder extracts. The SERS-based detection of azorubine (E122) in commercial available beverages with different complexity (e.g. sugar content, alcohol concentration) illustrates the strong potential of SERS as a qualitative as well as semiquantitative prescan method in food analytics. Here, a good agreement between the estimated concentration employing SERS as well as the gold standard technique HPLC, a highly laborious method, is found. Finally, SERS is applied to detect vitamin B2 and B12 in cereals as well as the estimate the ratio of lycopene and β-carotene in tomatoes. Acknowledgement: Funding the projects "QuantiSERS" and "Jenaer Biochip Initiative 2.0" within the framework "InnoProfile Transfer - Unternehmen Region" the Federal Ministry of Education and Research, Germany (BMBF) is gratefully acknowledged.

  8. Tritium labelling of highly selective probes for. delta. -opioid receptors: ( sup 3 H)Tyr-D-Ser(O-t-Bu)-Gly-Phe-Leu-Thr(DSTBULET) and ( sup 3 H)Tyr-D-Ser(O-t-Bu)-Gly-Phe-Leu-Thr(O-t-Bu)(BUBU)

    Energy Technology Data Exchange (ETDEWEB)

    Fellion, E.; Gacel, G.; Roques, B.P. (Institut National de la Sante et de la Recherche Medicale (INSERM), 75 - Paris (France)); Roy, J.; Morgat, J.L. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service de Biochimie)

    1990-08-01

    The introduction of bulky residue(s) in linear enkephalin-related hexapeptides represents a new approach in the design of selective probes for {delta}-opioid receptors, displaying the appropriate criteria to investigate biological and pharmacological properties of the assumed binding site ({delta}) of endogenous enkephalins. The selectivities and high affinities of Tyr-D-Ser(O-t-Bu)-Gly-Phe-Leu-Thr(DSTBULET) and especially Tyr-D-Ser(O-t-Bu)Gly-Phe-Leu-Thr(O-t-Bu) (BUBU) associated with a satisfactory resistance to peptidases, make them the most suitable {delta}-probes reported to date. In the present paper, we report the synthesis of DSTBULET and BUBU under tritiated forms with high specific radioactivities. These radio-labelled probes will enable extensive in vitro and in vivo investigations of {delta}-opioid receptors properties to be carried out. (author).

  9. A SERS-active sensor based on heterogeneous gold nanostar core-silver nanoparticle satellite assemblies for ultrasensitive detection of aflatoxinB1.

    Science.gov (United States)

    Li, Aike; Tang, Lijuan; Song, Dan; Song, Shanshan; Ma, Wei; Xu, Liguang; Kuang, Hua; Wu, Xiaoling; Liu, Liqiang; Chen, Xin; Xu, Chuanlai

    2016-01-28

    A surface-enhanced Raman scattering (SERS) sensor based on gold nanostar (Au NS) core-silver nanoparticle (Ag NP) satellites was fabricated for the first time to detect aflatoxinB1 (AFB1). We constructed the SERS sensor using AFB1 aptamer (DNA1)-modified Ag satellites and a complementary sequence (DNA2)-modified Au NS core. The Raman label (ATP) was modified on the surface of Ag satellites. The SERS signal was enhanced when the satellite NP was attached to the Au core NS. The AFB1 aptamer on the surface of Ag satellites would bind to the targets when AFB1 was present in the system, Ag satellites were then removed and the SERS signal decreased. This SERS sensor showed superior specificity for AFB1 and the linear detection range was from 1 to 1000 pg mL(-1) with the limit of detection (LOD) of 0.48 pg mL(-1). The excellent recovery experiment using peanut milk demonstrated that the sensor could be applied in food and environmental detection.

  10. Development of surface enhanced Raman scattering (SERS) spectroscopy monitoring of fuel markers to prevent fraud

    Science.gov (United States)

    Wilkinson, Timothy; Clarkson, John; White, Peter C.; Meakin, Nicholas; McDonald, Ken

    2013-05-01

    Governments often tax fuel products to generate revenues to support and stimulate their economies. They also subsidize the cost of essential fuel products. Fuel taxation and subsidization practices are both subject to fraud. Oil marketing companies also suffer from fuel fraud with loss of legitimate sales and additional quality and liability issues. The use of an advanced marking system to identify and control fraud has been shown to be effective in controlling illegal activity. DeCipher has developed surface enhanced Raman scattering (SERS) spectroscopy as its lead technology for measuring markers in fuel to identify and control malpractice. SERS has many advantages that make it highly suitable for this purpose. The SERS instruments are portable and can be used to monitor fuel at any point in the supply chain. SERS shows high specificity for the marker, with no false positives. Multiple markers can also be detected in a single SERS analysis allowing, for example, specific regional monitoring of fuel. The SERS analysis from fuel is also quick, clear and decisive, with a measurement time of less than 5 minutes. We will present results highlighting our development of the use of a highly stable silver colloid as a SERS substrate to measure the markers at ppb levels. Preliminary results from the use of a solid state SERS substrate to measure fuel markers will also be presented.

  11. Quiero ser citado

    Directory of Open Access Journals (Sweden)

    Leonardo Romero

    2011-05-01

    Full Text Available Después de varios años de ser editor, muchos de mis jefes confunden la revista con el editor, y es común oír cosas como “conferencia a cargo de la revista” o en conversaciones se dirijan a mí para decir “y porque no te citan”, refiriéndose al motivo porqué la Rev peru biol. no es citada por otros trabajos. Aprovechando ese desquicio, en los siguientes párrafos encarnare a la revista y al editor, en la fusión mágica en la que algunos de mis jefes me imaginan.

  12. Graphene-Plasmonic Hybrid Platform for Label-Free SERS Biomedical Detection

    Science.gov (United States)

    Wang, Pu

    Surface Enhanced Raman Scattering (SERS) has attracted explosive interest for the wealth of vibrational information it provides with minimal invasive effects to target analyte. Nanotechnology, especially in the form of noble metal nanoparticles exhibit unique electromagnetic and chemical characteristics that are explored to realize ultra-sensitive SERS detection in chemical and biological analysis. Graphene, atom-thick carbon monolayer, exhibits superior chemical stability and bio-compatibility. A combination of SERS-active metal nanostructures and graphene will create various synergies in SERS. The main objective of this research was to exploit the applications of the graphene-Au tip hybrid platform in SERS. The hybrid platform consists of a periodic Au nano-pyramid substrate to provide reproducible plasmonic enhancement, and the superimposed monolayer graphene sheet, serving as "built-in" Raman marker. Extensive theoretical and experimental studies were conducted to determine the potentials of the hybrid platform as SERS substrate. Results from both Finite-Domain Time-Domain (FDTD) numerical simulation and Raman scattering of graphene suggested that the hybrid platform boosted a high density of hotspots yielding 1000 times SERS enhancement of graphene bands. Ultra-high sensitivity of the hybrid platform was demonstrated by bio-molecules including dye, protein and neurotransmitters. Dopamine and serotonin can be detected and distinguished at 10-9 M concentration in the presence of human body fluid. Single molecule detection was obtained using a bi-analyte technique. Graphene supported a vibration mode dependent SERS chemical enhancement of ˜10 to the analyte. Quantitative evaluation of hotspots was presented using spatially resolved Raman mapping of graphene SERS enhancement. Graphene plays a crucial role in quantifying SERS hotspots and paves the path for defining SERS EF that could be universally applied to various SERS systems. A reproducible and statistically

  13. Aprendendo a ser psicoterapeuta

    Directory of Open Access Journals (Sweden)

    Elizabeth Amelio Faleiros

    Full Text Available Este estudo investiga, na perspectiva de Jacob Levy Moreno, a concepção que alunos de Psicologia têm sobre o que é ser psicoterapeuta, quais elementos são necessários para o desenvolvimento dessa tarefa e os fatores impeditivos para realizá-la. Propõe formas de soluções para o desempenho daquela função, favorecendo a reflexão sobre a importância dessa tarefa e a responsabilidade do profissional junto ao paciente. A metodologia utilizada é a qualitativa, pois esta permite abordar dimensões da subjetividade dos sujeitos. Os resultados revelam que os alunos possuem em sua concepção os alicerces básicos, cujos indicadores são apontados por Moreno e por outros autores, percebem os requisitos básicos que constituem a essência do papel de terapeuta, evidenciam críticas realistas sobre os fatores limitadores e sugerem ações pedagógicas para minimizá-los.

  14. Mechanistic studies on β-ketoacyl thiolase from Zoogloea ramigera: Identification of the active-site nucleophile as Cys89, its mutation to Ser89, and kinetic and thermodynamic characterization of wild-type and mutant enzymes

    International Nuclear Information System (INIS)

    Thompson, S.; Mayerl, F.; Walsh, C.T.; Peoples, O.P.; Masamune, S.; Sinskey, A.J.

    1989-01-01

    Thiolase proceeds via covalent catalysis involving an acetyl-S-enzyme. The active-site thiol nucleophile is identified as Cys 89 by acetylation with [ 14 C]acetyl-CoA, rapid denaturation, tryptic digestion, and sequencing of the labeled peptide. The native acetyl enzyme is labile to hydrolytic decomposition with t 1/2 of 2 min at pH 7, 25 degree C. Cys 89 has been converted to the alternate nucleophile Ser 89 by mutagenesis and the C89S enzyme overproduced, purified, and assessed for activity. The Ser 89 enzyme retains 1% of the V max of the Cys 89 enzyme in the direction of acetoacetyl-CoA thiolytic cleavage and 0.05% of the V max in the condensation of two acetyl-CoA molecules. A covalent acetyl-O-enzyme intermediate is detected on incubation with [ 14 C]acetyl-CoA and isolation of the labeled Ser 89 -containing tryptic peptide. Comparisons of the Cys 89 and Ser 89 enzymes have been made for kinetic and thermodynamic stability of the acetyl enzyme intermediates both by isolation and by analysis of [ 32 P]CoASH/acetyl-CoA partial reactions and for rate-limiting steps in catalysis with trideuterioacetyl-CoA

  15. Neonatal High Bone Mass With First Mutation of the NF-κB Complex: Heterozygous De Novo Missense (p.Asp512Ser) RELA (Rela/p65).

    Science.gov (United States)

    Frederiksen, Anja L; Larsen, Martin J; Brusgaard, Klaus; Novack, Deborah V; Knudsen, Peter Juel Thiis; Schrøder, Henrik Daa; Qiu, Weimin; Eckhardt, Christina; McAlister, William H; Kassem, Moustapha; Mumm, Steven; Frost, Morten; Whyte, Michael P

    2016-01-01

    Heritable disorders that feature high bone mass (HBM) are rare. The etiology is typically a mutation(s) within a gene that regulates the differentiation and function of osteoblasts (OBs) or osteoclasts (OCs). Nevertheless, the molecular basis is unknown for approximately one-fifth of such entities. NF-κB signaling is a key regulator of bone remodeling and acts by enhancing OC survival while impairing OB maturation and function. The NF-κB transcription complex comprises five subunits. In mice, deletion of the p50 and p52 subunits together causes osteopetrosis (OPT). In humans, however, mutations within the genes that encode the NF-κB complex, including the Rela/p65 subunit, have not been reported. We describe a neonate who died suddenly and unexpectedly and was found at postmortem to have HBM documented radiographically and by skeletal histopathology. Serum was not available for study. Radiographic changes resembled malignant OPT, but histopathological investigation showed morphologically normal OCs and evidence of intact bone resorption excluding OPT. Furthermore, mutation analysis was negative for eight genes associated with OPT or HBM. Instead, accelerated bone formation appeared to account for the HBM. Subsequently, trio-based whole exome sequencing revealed a heterozygous de novo missense mutation (c.1534_1535delinsAG, p.Asp512Ser) in exon 11 of RELA encoding Rela/p65. The mutation was then verified using bidirectional Sanger sequencing. Lipopolysaccharide stimulation of patient fibroblasts elicited impaired NF-κB responses compared with healthy control fibroblasts. Five unrelated patients with unexplained HBM did not show a RELA defect. Ours is apparently the first report of a mutation within the NF-κB complex in humans. The missense change is associated with neonatal osteosclerosis from in utero increased OB function rather than failed OC action. These findings demonstrate the importance of the Rela/p65 subunit within the NF-κB pathway for human

  16. Studies of the Gly482Ser polymorphism of the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) gene in Danish subjects with the metabolic syndrome

    DEFF Research Database (Denmark)

    Ambye, L; Rasmussen, S; Fenger, Mogens

    2005-01-01

    The peroxisome proliferator-activated receptor gamma co-activator 1alpha (PGC-1alpha) is a novel transcriptional co-activator that holds an important role in lipid and glucose metabolism. PGC-1alpha is a candidate gene for the metabolic syndrome (MS) as well as type 2 diabetes. Recent studies...... related to this syndrome. The variant was examined, using PCR-RFLP, in the DanMONICA cohort comprising a population-based sample of 2349 subjects. MS was defined using the National Cholesterol Education Program -- Adult Treatment Panel III (NCEP-ATPIII) criteria. The allelic frequency of the Ser482 allele...... and insulin secretion, 24-ambulatory blood pressure or left ventricular mass index. In conclusion, the Gly482Ser polymorphism of the PGC-1alpha gene is not associated with the metabolic syndrome, related quantitative traits or cardiac hypertrophy among Danish Caucasian subjects...

  17. The IkappaB kinase family phosphorylates the Parkinson's disease kinase LRRK2 at Ser935 and Ser910 during Toll-like receptor signaling.

    Directory of Open Access Journals (Sweden)

    Nicolas Dzamko

    Full Text Available Mutations in leucine-rich repeat kinase 2 (LRRK2 are strongly associated with late-onset autosomal dominant Parkinson's disease. LRRK2 is highly expressed in immune cells and recent work points towards a link between LRRK2 and innate immunity. Here we demonstrate that stimulation of the Toll-Like Receptor (TLR pathway by MyD88-dependent agonists in bone marrow-derived macrophages (BMDMs or RAW264.7 macrophages induces marked phosphorylation of LRRK2 at Ser910 and Ser935, the phosphorylation sites that regulate the binding of 14-3-3 to LRRK2. Phosphorylation of these residues is prevented by knock-out of MyD88 in BMDMs, but not the alternative TLR adaptor protein TRIF. Utilising both pharmacological inhibitors, including a new TAK1 inhibitor, NG25, and genetic models, we provide evidence that both the canonical (IKKα and IKKβ and IKK-related (IKKε and TBK1 kinases mediate TLR agonist induced phosphorylation of LRRK2 in vivo. Moreover, all four IKK members directly phosphorylate LRRK2 at Ser910 and Ser935 in vitro. Consistent with previous work describing Ser910 and Ser935 as pharmacodynamic biomarkers of LRRK2 activity, we find that the TLR independent basal phosphorylation of LRRK2 at Ser910 and Ser935 is abolished following treatment of macrophages with LRRK2 kinase inhibitors. However, the increased phosphorylation of Ser910 and Ser935 induced by activation of the MyD88 pathway is insensitive to LRRK2 kinase inhibitors. Finally, employing LRRK2-deficient BMDMs, we present data indicating that LRRK2 does not play a major role in regulating the secretion of inflammatory cytokines induced by activation of the MyD88 pathway. Our findings provide the first direct link between LRRK2 and the IKKs that mediate many immune responses. Further work is required to uncover the physiological roles that phosphorylation of LRRK2 by IKKs play in controlling macrophage biology and to determine how phosphorylation of LRRK2 by IKKs impacts upon the use of Ser

  18. Batch fabrication of disposable screen printed SERS arrays.

    Science.gov (United States)

    Qu, Lu-Lu; Li, Da-Wei; Xue, Jin-Qun; Zhai, Wen-Lei; Fossey, John S; Long, Yi-Tao

    2012-03-07

    A novel facile method of fabricating disposable and highly reproducible surface-enhanced Raman spectroscopy (SERS) arrays using screen printing was explored. The screen printing ink containing silver nanoparticles was prepared and printed on supporting materials by a screen printing process to fabricate SERS arrays (6 × 10 printed spots) in large batches. The fabrication conditions, SERS performance and application of these arrays were systematically investigated, and a detection limit of 1.6 × 10(-13) M for rhodamine 6G could be achieved. Moreover, the screen printed SERS arrays exhibited high reproducibility and stability, the spot-to-spot SERS signals showed that the intensity variation was less than 10% and SERS performance could be maintained over 12 weeks. Portable high-throughput analysis of biological samples was accomplished using these disposable screen printed SERS arrays.

  19. Analytical characterization using surface-enhanced Raman scattering (SERS) and microfluidic sampling

    International Nuclear Information System (INIS)

    Wang, Chao; Yu, Chenxu

    2015-01-01

    With the rapid development of analytical techniques, it has become much easier to detect chemical and biological analytes, even at very low detection limits. In recent years, techniques based on vibrational spectroscopy, such as surface enhanced Raman spectroscopy (SERS), have been developed for non-destructive detection of pathogenic microorganisms. SERS is a highly sensitive analytical tool that can be used to characterize chemical and biological analytes interacting with SERS-active substrates. However, it has always been a challenge to obtain consistent and reproducible SERS spectroscopic results at complicated experimental conditions. Microfluidics, a tool for highly precise manipulation of small volume liquid samples, can be used to overcome the major drawbacks of SERS-based techniques. High reproducibility of SERS measurement could be obtained in continuous flow generated inside microfluidic devices. This article provides a thorough review of the principles, concepts and methods of SERS-microfluidic platforms, and the applications of such platforms in trace analysis of chemical and biological analytes. (topical review)

  20. Solidification of highly active wastes

    International Nuclear Information System (INIS)

    Morris, J.B.

    1986-07-01

    This document contains the annual reports for the contracts: (A) Glass Technology; (B) Calcination of Highly Active Waste Liquors; (C) Formation and Trapping of Volatile Ruthenium; (D) Deposition of Ruthenium; (E) Enhancement of Off-Gas Aerosol Collection; (F) Volatilisation of Cs, Tc and Te in High Level Waste Vitrification. (author)

  1. Western Canada: high prices, high activity

    International Nuclear Information System (INIS)

    Savidant, S

    2000-01-01

    The forces responsible for the high drilling and exploration activity in Western Canada (recent high prices, excess pipeline capacity, and the promise of as yet undiscovered natural gas resources) are discussed. Supply and demand signposts, among them weather impacts, political response by governments, the high demand for rigs and services, the intense competition for land, the scarcity of qualified human resources, are reviewed/. The geological potential of Western Canada, the implications of falling average pool sizes, the industry's ability to catch up to increasing declines, are explored. The disappearance of easy large discoveries, rising development costs involved in smaller, more complex hence more expensive pools are assessed and the Canadian equity and capital markets are reviewed. The predicted likely outcome of all the above factors is fewer players, increasing expectation of higher returns, and more discipline among the remaining players

  2. and Au nanoparticles for SERS applications

    Directory of Open Access Journals (Sweden)

    Fazio Enza

    2018-01-01

    Full Text Available The morphological and optical properties of noble metal nanoparticles prepared by picosecond laser generated plasmas in water were investigated. First, the ablation efficiency was maximized searching the optimal focusing conditions. The nanoparticle size, measured by Scanning Transmission Electron Microscopy, strongly depends on the laser fluence, keeping fixed the other deposition parameters such as the target to scanner objective distance and laser repetition frequency. STEM images indicate narrow gradients of NP sizes. Hence the optimization of ablation parameters favours a fine tuning of nanoparticles. UV-Visible spectroscopy helped to determine the appropriate laser wavelength to resonantly excite the localized surface plasmon to carry out Surface Enhanced Raman Scattering (SERS measurements. The SERS activity of Ag and Au substrates, obtained spraying the colloids synthesized in water, was tested using crystal violet as a probe molecule. The good SERS performance, observed at excitation wavelength 785 nm, is attributed to aggregation phenomena of nanoparticles sprayed on the support.

  3. Effect of Interface energy and electron transfer on shape, plasmon resonance and SERS activity of supported surfactant-free gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Giangregorio, Maria M. [Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP; Dastmalchi, Babak [Ames Laboratory; Suvorova, Alexandra [University of Western Australia; Bianco, Giuseppe V. [Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP; Hingerl, Kurt [Johannes Kepler University Linz; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP; Losurdo, Maria [Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP

    2014-01-01

    For device integration purposes plasmonic metal nanoparticles must be supported/deposited on substrates. Therefore, it is important to understand the interaction between surfactant-free plasmonic metal nanoparticles and different substrates, as well as to identify factors that drive nanoparticles nucleation and formation. Here we show that for nanoparticles grown directly on supports, the substrate/nanoparticle interfacial energy affects the equilibrium shape of nanoparticles. Therefore, oblate, spherical and prolate Au nanoparticles (NPs) with different shapes have been deposited by radiofrequency sputtering on substrates with different characteristics, namely a dielectric oxide Al2O3 (0001), a narrow bandgap semiconductor Si (100), and a polar piezoelectric wide bandgap semiconductor 4H–SiC (0001). We demonstrate that the higher the substrate surface energy, the higher the interaction with the substrate, resulting in flat prolate Au nanoparticles. The resulting localized surface plasmon resonance characteristics of Au NPs/Al2O3, Au NPs/Si and Au NPs/SiC have been determined by spectroscopic ellipsometry and correlated with their structure and shape studied by transmission electron microscopy. Finally, we have demonstrated the diverse response of the tailored plasmonic substrates as ultrasensitive SERS chemical sensors. Flat oblates Au NPs on SiC result in an enhanced and more stable SERS response. The experimental findings are validated by numerical simulations of electromagnetic fields.

  4. High surface enhanced Raman scattering activity of BN nanosheets–Ag nanoparticles hybrids

    International Nuclear Information System (INIS)

    Yang, Shanshan; Zhang, Zhaochun; Zhao, Jun; Zheng, Houli

    2014-01-01

    Highlights: • Boron nitride–silver nanohybrid was acquired through a liquid-phase reducing route. • The composite shown a high-quality SERS activity. • 2-Mercaptobenzimidazole was chemisorbed on silver surface in vertical orientation. -- Abstract: A facile liquid-phase reducing route was developed to modify boron nitride (BN) nanosheets with silver nanoparticles (AgNPs) in order to fabricate BN–AgNPs hybrids with high surface enhanced Raman scattering (SERS) activity. The layered structure and morphology of BN–AgNPs nanohybrids were characterized by transmission electron microscopy and atomic force microscopy, meanwhile, Fourier transform infrared spectroscopy and ultraviolet–visible were used for studying optical properties and surface plasmon resonance applied to the optical sensor. The SERS of adsorbed 2-mercaptobenzimidazole (MBI) molecule was investigated which shown that the BN–AgNPs substrate exhibited a very strong SERS activity, offering a great potential application in molecular probe sensor. On the basis of the analysis of SERS and the Raman surface selection rules, we could draw a conclusion that the MBI molecule was adsorbed upright on the AgNPs surface through the sulphur and nitrogen atoms. What is more, the cyclic voltammetry experiment indicated the electrochemically irreversible behavior of BN–AgNPs nanohybrids in KCl solution

  5. TLC-SERS Plates with a Built-In SERS Layer Consisting of Cap-Shaped Noble Metal Nanoparticles Intended for Environmental Monitoring and Food Safety Assurance

    Directory of Open Access Journals (Sweden)

    H. Takei

    2015-01-01

    Full Text Available We report on a thin layer chromatograph (TLC with a built-in surface enhanced Raman scattering (SERS layer for in-situ identification of chemical species separated by TLC. Our goal is to monitor mixture samples or diluted target molecules suspended in a host material, as happens often in environmental monitoring or detection of food additives. We demonstrate that the TLC-SERS can separate mixture samples and provide in-situ SERS spectra. One sample investigated was a mixture consisting of equal portions of Raman-active chemical species, rhodamine 6 G (R6G, crystal violet (CV, and 1,2-di(4-pyridylethylene (BPE. The three components could be separated and their SERS spectra were obtained from different locations. Another sample was skim milk with a trace amount of melamine. Without development, no characteristic peaks were observed, but after development, a peak was observed at 694 cm−1. Unlike previous TLC-SERS whereby noble metal nanoparticles are added after development of a sample, having a built-in SERS layer greatly facilitates analysis as well as maintaining high uniformity of noble metal nanoparticles.

  6. Self-catalytic stabilized Ag-Cu nanoparticles with tailored SERS response for plasmonic photocatalysis

    Science.gov (United States)

    He, Lili; Liu, Changqing; Tang, Jia; Zhou, Youchen; Yang, Hui; Liu, Ruiyu; Hu, Jiugang

    2018-03-01

    In-situ SERS monitoring of direct plasmon-driven photocatalysis was achieved using relatively earth-abundant Cu NPs following their decoration with tiny amounts of silver, which promoted excellent SERS and high catalytic activity. The SERS and catalytic performance of the Ag-Cu NPs can be tuned by changing their composition. In particular, it was found that the surface oxidation state of copper could be switched to its metallic state via self-plasmon catalysis under laser irradiation, highlighting the potential of air-unstable copper NPs as stable plasmonic catalysts. These dual functional Ag-Cu NPs were used for SERS real-time monitoring of plasmon-driven photocatalysis reactions involving the degradation of Rhodamine 6G and the dimerization of 4-nitrothiophenol. The corresponding catalytic reaction mechanisms were discussed.

  7. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    Science.gov (United States)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  8. Colloidal systems of silver nanoparticles and high-regioregular cationic polythiophene with ionic-liquid-like pendant groups: Optical properties and SERS.

    Science.gov (United States)

    Kazim, Samrana; Pfleger, Jiří; Procházka, Marek; Bondarev, Dmitrij; Vohlídal, Jiří

    2011-02-15

    We report tuning of structure dependent optical properties of colloidal systems of borate-stabilized silver nanoparticles (Ag NPs) and polythiophene-based cationic polyelectrolyte with ionic-liquid like side groups: poly{3-[6-(1-methylimidazolium-3-yl)hexyl]thiophene-2,5-diyl bromide} (PMHT-Br) towards obtaining local electromagnetic field enhancement effects. Surface-enhanced Raman scattering (SERS) studies showed that the strong electromagnetic field enhancement is related to the formation of aggregates of Ag NPs achieved at the components ratio providing the charge balance between Ag NPs and cationic polythiophene, at which Ag NPs are nearly single-polymer-layer coated, their zeta potential is close to zero and they easily form aggregates in which the mean inter-particle distance enables the occurrence of desired plasmonic effects. Fluorescence quenching is efficient only in the systems with low concentrations of PMHT-Br, in which almost all polymer chains directly interact with the Ag NPs surface. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Cyanuric acid hydrolase from Azorhizobium caulinodans ORS 571: crystal structure and insights into a new class of Ser-Lys dyad proteins.

    Directory of Open Access Journals (Sweden)

    Seunghee Cho

    Full Text Available Cyanuric acid hydrolase (CAH catalyzes the hydrolytic ring-opening of cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, an intermediate in s-triazine bacterial degradation and a by-product from disinfection with trichloroisocyanuric acid. In the present study, an X-ray crystal structure of the CAH-barbituric acid inhibitor complex from Azorhizobium caulinodans ORS 571 has been determined at 2.7 Å resolution. The CAH protein fold consists of three structurally homologous domains forming a β-barrel-like structure with external α-helices that result in a three-fold symmetry, a dominant feature of the structure and active site that mirrors the three-fold symmetrical shape of the substrate cyanuric acid. The active site structure of CAH is similar to that of the recently determined AtzD with three pairs of active site Ser-Lys dyads. In order to determine the role of each Ser-Lys dyad in catalysis, a mutational study using a highly sensitive, enzyme-coupled assay was conducted. The 10⁹-fold loss of activity by the S226A mutant was at least ten times lower than that of the S79A and S333A mutants. In addition, bioinformatics analysis revealed the Ser226/Lys156 dyad as the only absolutely conserved dyad in the CAH/barbiturase family. These data suggest that Lys156 activates the Ser226 nucleophile which can then attack the substrate carbonyl. Our combination of structural, mutational, and bioinformatics analyses differentiates this study and provides experimental data for mechanistic insights into this unique protein family.

  10. Label-free in situ SERS imaging of biofilms.

    Science.gov (United States)

    Ivleva, Natalia P; Wagner, Michael; Szkola, Agathe; Horn, Harald; Niessner, Reinhard; Haisch, Christoph

    2010-08-12

    Surface-enhanced Raman scattering (SERS) is a promising technique for the chemical characterization of biological systems. It yields highly informative spectra, can be applied directly in aqueous environment, and has high sensitivity in comparison with normal Raman spectroscopy. Moreover, SERS imaging can provide chemical information with spatial resolution in the micrometer range (chemical imaging). In this paper, we report for the first time on the application of SERS for in situ, label-free imaging of biofilms and demonstrate the suitability of this technique for the characterization of the complex biomatrix. Biofilms, being communities of microorganisms embedded in a matrix of extracellular polymeric substances (EPS), represent the predominant mode of microbial life. Knowledge of the chemical composition and the structure of the biofilm matrix is important in different fields, e.g., medicine, biology, and industrial processes. We used colloidal silver nanoparticles for the in situ SERS analysis. Good SERS measurement reproducibility, along with a significant enhancement of Raman signals by SERS (>10(4)) and highly informative SERS signature, enables rapid SERS imaging (1 s for a single spectrum) of the biofilm matrix. Altogether, this work illustrates the potential of SERS for biofilm analysis, including the detection of different constituents and the determination of their distribution in a biofilm even at low biomass concentration.

  11. A Ag synchronously deposited and doped TiO2 hybrid as an ultrasensitive SERS substrate: a multifunctional platform for SERS detection and photocatalytic degradation.

    Science.gov (United States)

    Yang, Libin; Sang, Qinqin; Du, Juan; Yang, Ming; Li, Xiuling; Shen, Yu; Han, Xiaoxia; Jiang, Xin; Zhao, Bing

    2018-06-06

    Ag simultaneously deposited and doped TiO2 (Ag-TiO2) hybrid nanoparticles (NPs) were prepared via a sol-hydrothermal method, as both a sensitive surface-enhanced Raman scattering (SERS) substrate and a superior photocatalyst for the first time. Ag-TiO2 hybrid NPs exhibit excellent SERS performance for several probe molecules and the enhancement factor is calculated to be 1.86 × 105. The detection limit of the 4-mercaptobenzoic acid (4-MBA) probe on the Ag-TiO2 substrate is 1 × 10-9 mol L-1, which is four orders of magnitude lower than that on pure TiO2 as a consequence of the synergistic effects of TiO2 and Ag. This is the highest SERS sensitivity among the reported semiconductor substrates and even comparable to noble metal substrates, and a SERS enhancement mechanism from the synergistic contribution of the semiconductor and noble metal was proposed. And importantly, the Ag-TiO2 hybrid shows excellent photocatalytic degradation activity for the detected species under UV light irradiation at lower concentration conditions, even for the hard to degrade 4-MBA molecule. This makes the Ag-TiO2 hybrid promising as a dual-function platform for both highly sensitive SERS detection and photocatalytic degradation of a pollutant system. Moreover, it also proves that the Ag-TiO2 hybrid can serve as a promising recyclable SERS-active substrate by virtue of its photocatalytic self-cleaning properties for some specific applications, for instance comparative studies of different species on the same SERS platform, in addition to the economic benefit.

  12. ser en ortodoncia

    OpenAIRE

    Ruíz-Esculpi, María; Ricse-Chaupis, Estela; Villanueva-Vega, Judith; Torres-Maita, Liz

    2014-01-01

    La primera aplicación del láser en un diente fue realizada en 1965. Desde entonces ha presentado una constante evolución y desarrollo. La tecnología láser permite realizar procedimientos en tejidos duros y blandos, pudiendo ser utilizado con las siguientes finalidades: como prevención de la desmineralización, en la adhesión y remoción de brackets, en la reducción del dolor producto del movimiento dental, en la reparación ósea después de la expansión, en diversas cirugías y otras aplicaciones ...

  13. A 6.25 Gb/s equalizer in 0.18 μm CMOS technology for high-speed SerDes

    International Nuclear Information System (INIS)

    Zhang Mingke; Hu Qingsheng

    2013-01-01

    This paper presents a 0.18 μm CMOS 6.25 Gb/s equalizer for high speed backplane communication. The proposed equalizer is a combined one consisting of a one-tap feed-forward equalizer (FFE) and a two-tap half-rate decision feedback equalizer (DFE) in order to cancel both pre-cursor and post-cursor ISI. By employing an active-inductive peaking circuit for the delay line, the bandwidth of the FFE is increased and the area cost is minimized. CML-based circuits such as DFFs, summers and multiplexes all help to improve the speed of DFEs. Measurement results illustrate that the equalizer operates well when equalizing 6.25 Gb/s data is passed over a 30-inch channel with a loss of 22 dB and consumes 55.8 mW with the supply voltage of 1.8 V. The overall chip area including pads is 0.3 × 0.5 mm 2 . (semiconductor integrated circuits)

  14. High-Activity Dealloyed Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  15. La importancia de ser grande

    OpenAIRE

    Baisre, J. A.

    2007-01-01

    Se responde a las preguntas ¿por qué los mamíferos marinos son los animales más grandes del planeta?, ¿Por qué los peces no pueden ser más grandes?. Éstas y otras interrogantes son respondidas de forma sencilla y clara.

  16. Ser/Thr Phosphorylation Regulates the Fatty Acyl-AMP Ligase Activity of FadD32, an Essential Enzyme in Mycolic Acid Biosynthesis*

    Science.gov (United States)

    Le, Nguyen-Hung; Molle, Virginie; Eynard, Nathalie; Miras, Mathieu; Stella, Alexandre; Bardou, Fabienne; Galandrin, Ségolène; Guillet, Valérie; André-Leroux, Gwenaëlle; Bellinzoni, Marco; Alzari, Pedro; Mourey, Lionel; Burlet-Schiltz, Odile; Daffé, Mamadou; Marrakchi, Hedia

    2016-01-01

    Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is a well known source of antituberculous drug targets. Among the promising new targets in the pathway, FadD32 is an essential enzyme required for the activation of the long meromycolic chain of mycolic acids and is essential for mycobacterial growth. Following the in-depth biochemical, biophysical, and structural characterization of FadD32, we investigated its putative regulation via post-translational modifications. Comparison of the fatty acyl-AMP ligase activity between phosphorylated and dephosphorylated FadD32 isoforms showed that the native protein is phosphorylated by serine/threonine protein kinases and that this phosphorylation induced a significant loss of activity. Mass spectrometry analysis of the native protein confirmed the post-translational modifications and identified Thr-552 as the phosphosite. Phosphoablative and phosphomimetic FadD32 mutant proteins confirmed both the position and the importance of the modification and its correlation with the negative regulation of FadD32 activity. Investigation of the mycolic acid condensation reaction catalyzed by Pks13, involving FadD32 as a partner, showed that FadD32 phosphorylation also impacts the condensation activity. Altogether, our results bring to light FadD32 phosphorylation by serine/threonine protein kinases and its correlation with the enzyme-negative regulation, thus shedding a new horizon on the mycolic acid biosynthesis modulation and possible inhibition strategies for this promising drug target. PMID:27590338

  17. SERS sensors for DVD platform

    DEFF Research Database (Denmark)

    Brøgger, Anna Line

    This Ph.D. thesis explores the engineering of a portable sensor system for detection of rare and small molecules. The Ph.D. project is part of the research project 'Multi-Sensor DVD platform' (MUSE), aiming to integrate different sensors on a rotating disc. The sensors are chosen to complement each...... other, creating more reliable and stable results for the end user. The rotating disc comprises microfluidic channels, which can be utilized for handling and manipulating liquid samples such as blood or water. The focus of this Ph.D. thesis, is on the integration of one specific sensor on a rotating disc....... The sensor is based upon surface enhanced Raman spectroscopy (SERS), which detects molecular vibrations. The aim of this thesis is to cover the different aspects of the sensor system. SERS substrates, consisting of nanopillars with gold or silver caps on top, have been fabricated by standard micro and nano...

  18. Why Ser and not Thr brokers catalysis in the trypsin fold.

    Science.gov (United States)

    Pelc, Leslie A; Chen, Zhiwei; Gohara, David W; Vogt, Austin D; Pozzi, Nicola; Di Cera, Enrico

    2015-02-24

    Although Thr is equally represented as Ser in the human genome and as a nucleophile is as good as Ser, it is never found in the active site of the large family of trypsin-like proteases that utilize the Asp/His/Ser triad. The molecular basis of the preference of Ser over Thr in the trypsin fold was investigated with X-ray structures of the thrombin mutant S195T free and bound to an irreversible active site inhibitor. In the free form, the methyl group of T195 is oriented toward the incoming substrate in a conformation seemingly incompatible with productive binding. In the bound form, the side chain of T195 is reoriented for efficient substrate acylation without causing steric clash within the active site. Rapid kinetics prove that this change is due to selection of an active conformation from a preexisting ensemble of reactive and unreactive rotamers whose relative distribution determines the level of activity of the protease. Consistent with these observations, the S195T substitution is associated with a weak yet finite activity that allows identification of an unanticipated important role for S195 as the end point of allosteric transduction in the trypsin fold. The S195T mutation abrogates the Na(+)-dependent enhancement of catalytic activity in thrombin, activated protein C, and factor Xa and significantly weakens the physiologically important allosteric effects of thrombomodulin on thrombin and of cofactor Va on factor Xa. The evolutionary selection of Ser over Thr in trypsin-like proteases was therefore driven by the need for high catalytic activity and efficient allosteric regulation.

  19. Mutation of the Ser18 phosphorylation site on the sole Saccharomyces cerevisiae UCS protein, She4, can compromise high-temperature survival.

    Science.gov (United States)

    Gomez-Escalante, Susana; Piper, Peter W; Millson, Stefan H

    2017-01-01

    Folding of the myosin head often requires the joint actions of Hsp90 and a dedicated UNC45, Cro1, She4 (UCS) domain-containing cochaperone protein. Relatively weak sequence conservation exists between the single UCS protein of simple eukaryotes (She4 in budding yeast) and the two UCS proteins of higher organisms (the general cell and smooth muscle UNC45s; UNC45-GC and UNC45-SM respectively). In vertebrates, UNC45-GC facilitates cytoskeletal function whereas the 55% identical UNC45-SM assists in the assembly of the contractile apparatus of cardiac and skeletal muscles. UNC45-SM, unlike UNC45-GC, shares with yeast She4 an IDSL sequence motif known to be a site of in vivo serine phosphorylation in yeast. Investigating this further, we found that both a non-phosphorylatable (S18A) and a phosphomimetic (S18E) mutant form of She4 could rescue the type 1 myosin localisation and endocytosis defects of the yeast she4Δ mutant at 39 °C. Nevertheless, at higher temperature (45 °C), only She4 (S18A), not She4(S18E), could substantially rescue the cell lysis defect of she4Δ mutant cells. In the yeast two-hybrid system, the non-phosphorylatable S18A and S251A mutant forms of She4 and UNC45-SM still displayed the stress-enhanced in vivo interaction with Hsp90 seen with the wild-type She4 and UNC45-SM. Such high-temperature enforcement to interaction was though lost with the phosphomimetic mutant forms (She4(S18E) and UNC45-SM (S251E)), an indication that phosphorylation might suppress these increases in She4/Hsp90 and UNC45-SM/Hsp90 interaction with stress.

  20. Tuning SERS for living erythrocytes

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Parshina, E.Y.; Khabanova, V.V.

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) is a unique technique to study submembrane hemoglobin (Hbsm) in erythrocytes. We report the detailed design of SERS experiments on living erythrocytes to estimate dependence of the enhancemen t factor for main Raman bands of Hbsm on silver nanoparticle (Ag......NP) properties. We demonstrate that the enhancement factor for 4/A1g, 10/B1g and A2g Raman bands of Hbsm varies from 105 to 107 under proposed experimental conditions with 473 nm laser excitation. For the first time we show that the enhancement of Raman scattering increases with the increase in the relative...... between small AgNPs and Hbsm and, consequently, leads to the higher enhancement of Raman scattering of Hbsm. The enhancement of higher wavenumber bands 10/B1g and A2g is more sensitive to AgNPs' size and the relative amount of small AgNPs than the enhancement of the lower wavenumber band 4/A1g. This can...

  1. por láser

    Directory of Open Access Journals (Sweden)

    Mayra Garcimuño

    2013-01-01

    Full Text Available En el presente trabajo, la técnica Espectroscopia de plasmas producidos por láser (Laser-induced breakdown spectroscopy –LIBS– se aplicó a la determinación cuan- titativa de Na en agua natural dulce, de interés en agricultura para el estudio de la alcalinidad de aguas de regadío. Para efectuar el análisis, se prepararon soluciones con concentraciones conocidas del analito, se mezclaron con óxido de calcio y se compactaron en pastillas sólidas. Los plasmas se produjeron en aire a presión atmos- férica utilizando un láser pulsado Nd:YAG. Se construyó una curva de calibración y se calculó el límite de detección. Se analizaron muestras de agua natural y los resultados se compararon con los obtenidos mediante espectroscopia de absorción atómica. Se demostró la factibilidad del método para la determinación de Na en agua natural dulce.

  2. SERS detection of biomolecules using lithographed nanoparticles towards a reproducible SERS biosensor

    Energy Technology Data Exchange (ETDEWEB)

    David, Catalina; Guillot, Nicolas; Chapelle, Marc Lamy de la [Laboratoire CSPBAT (FRE 3043), UFR SMBH, Universite Paris XIII, 74 rue Marcel Cachin, F-93017 Bobigny (France); Shen, Hong; Toury, Timothee, E-mail: marc.lamydelachapelle@univ-paris13.fr [ICD-LNIO-UMR, CNRS 6279, Universite de technologie de Troyes, 12 rue Marie Curie, F-10010 Troyes (France)

    2010-11-26

    In this paper we highlight the accurate spectral detection of bovine serum albumin and ribonuclease-A using a surface-enhanced Raman scattering (SERS) substrate based on gold nanocylinders obtained by electron-beam lithography (EBL). The nanocylinders have diameters from 100 to 180 nm with a gap of 200 nm. We demonstrate that optimizing the size and the shape of the lithographed gold nanocylinders, we can obtain SERS spectra of proteins at low concentration. This SERS study enabled us to estimate high enhancement factors (10{sup 5} for BSA and 10{sup 7} for RNase-A) of important bands in the protein Raman spectrum measured for 1 mM concentration. We demonstrate that, to reach the highest enhancement, it is necessary to optimize the SERS signal and that the main parameter of optimization is the LSPR position. The LSPR have to be suitably located between the laser excitation wavelength, which is 632.8 nm, and the position of the considered Raman band. Our study underlines the efficiency of gold nanocylinder arrays in the spectral detection of proteins.

  3. Facile fabrication of Ag dendrite-integrated anodic aluminum oxide membrane as effective three-dimensional SERS substrate

    Science.gov (United States)

    Zhang, Cong-yun; Lu, Ya; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

    2016-07-01

    A novel surface enhanced Raman scattering (SERS)-active substrate has been successfully developed, where Ag-dendrites are assembled on the surface and embedded in the channels of anodic aluminum oxide (AAO) membrane, via electrodeposition in AgNO3/PVP aqueous system. Reaction conditions were systematically investigated to attain the best Raman enhancement. The growth mechanism of Ag dendritic nanostructures has been proposed. The Ag dendrite-integrated AAO membrane with unique hierarchical structures exhibits high SERS activity for detecting rhodamine 6G with a detection limit as low as 1 × 10-11 M. Furthermore, the three-dimensional (3D) substrates display a good reproducibility with the average intensity variations at the major Raman peak less than 12%. Most importantly, the 3D SERS substrates without any surface modification show an outstanding SERS response for the molecules with weak affinity for noble metal surfaces. The potential application for the detection of polycyclic aromatic hydrocarbons (PAHs) was evaluated with fluoranthene as Raman target molecule and a sensitive SERS detection with a limit down to 10-8 M was reached. The 3D SERS-active substrate shows promising potential for rapid detection of trace organic pollutants even weak affinity molecules in the environment.

  4. An association between apo-A4 gene polymorphism (Thr347Ser ...

    African Journals Online (AJOL)

    Pramod Kumar

    Objective: We aimed at studying the relationship between apoA4 gene polymorphisms (Thr347Ser and ... showed significant association with lipid risk factors like high levels of ..... in German population showed that Ser347 allele is associated.

  5. Solidification of highly active wastes

    International Nuclear Information System (INIS)

    Morris, J.B.

    1984-11-01

    Final reports are presented on work on the following topics: glass technology; enhancement of off-gas aerosol collection; formation and trapping of volatile ruthenium; volatilisation of caesium, technetium and tellurium in high-level waste vitrification; deposition of ruthenium; and calcination of high-level waste liquors. (author)

  6. Ser do tempo em Bergson

    OpenAIRE

    Coelho,Jonas Gonçalves

    2004-01-01

    O artigo apresenta a concepção bergsoniana de duração. Pretende-se mostrar que, segundo Bergson, o tempo dos filósofos e cientistas é um tempo fictício, um esquema espacial que oculta a natureza do tempo real, o qual não pode ser separado dos acontecimentos físicos e psicológicos. Para Bergson, o tempo real é sucessão, continuidade, mudança, memória e criação. El presente artículo trata de la concepción bergsoniana de duración. Pretendemos mostrar que, según Bergson, el tiempo de los filós...

  7. Ser do tempo em Bergson

    OpenAIRE

    Coelho, Jonas Gonçalves

    2004-01-01

    O artigo apresenta a concepção bergsoniana de duração. Pretende-se mostrar que, segundo Bergson, o tempo dos filósofos e cientistas é um tempo fictício, um esquema espacial que oculta a natureza do tempo real, o qual não pode ser separado dos acontecimentos físicos e psicológicos. Para Bergson, o tempo real é sucessão, continuidade, mudança, memória e criação. We considered Bergson's duration concept. We intended to show that, according to Bergson, the time of philosophers and scientists i...

  8. Toward hybrid Au nanorods @ M (Au, Ag, Pd and Pt) core-shell heterostructures for ultrasensitive SERS probes

    Science.gov (United States)

    Xie, Xiaobin; Gao, Guanhui; Kang, Shendong; Lei, Yanhua; Pan, Zhengyin; Shibayama, Tamaki; Cai, Lintao

    2017-06-01

    Being able to precisely control the morphologies of noble metallic nanostructures is of essential significance for promoting the surface-enhanced Raman scattering (SERS) effect. Herein, we demonstrate an overgrowth strategy for synthesizing Au @ M (M = Au, Ag, Pd, Pt) core-shell heterogeneous nanocrystals with an orientated structural evolution and highly improved properties by using Au nanorods as seeds. With the same reaction condition system applied, we obtain four well-designed heterostructures with diverse shapes, including Au concave nanocuboids (Au CNs), Au @ Ag crystalizing face central cube nanopeanuts, Au @ Pd porous nanocuboids and Au @ Pt nanotrepangs. Subsequently, the exact overgrowth mechanism of the above heterostructural building blocks is further analysed via the systematic optimiziation of a series of fabrications. Remarkably, the well-defined Au CNs and Au @ Ag nanopeanuts both exhibit highly promoted SERS activity. We expect to be able to supply a facile strategy for the fabrication of multimetallic heterogeneous nanostructures, exploring the high SERS effect and catalytic activities.

  9. The secrets of highly active older adults.

    Science.gov (United States)

    Franke, Thea; Tong, Catherine; Ashe, Maureen C; McKay, Heather; Sims-Gould, Joanie

    2013-12-01

    Although physical activity is a recognized component in the management of many chronic diseases associated with aging, activity levels tend to progressively decline with increasing age (Manini & Pahor, 2009; Schutzer & Graves, 2004). In this article we examine the key factors that facilitate physical activity in highly active community-dwelling older adults. Using a strengths based approach, we examined the factors that facilitated physical activity in our sample of highly active older adults. Twenty-seven older adults participated in face-to face interviews. We extracted a sub-sample of 10 highly active older adults to be included in the analyses. Based on a framework analysis of our transcripts we identified three factors that facilitate physical activity in our sample, these include: 1) resourcefulness: engagement in self-help strategies such as self-efficacy, self-control and adaptability; 2) social connections: the presence of relationships (friend, neighborhood, institutions) and social activities that support or facilitate high levels of physical activity; and 3) the role of the built and natural environments: features of places and spaces that support and facilitate high levels of physical activity. Findings provide insight into, and factors that facilitate older adults' physical activity. We discuss implications for programs (e.g., accessible community centers, with appropriate programming throughout the lifecourse) and policies geared towards the promotion of physical activity (e.g., the development of spaces that facilitate both physical and social activities). © 2013.

  10. Dynamic SERS nanosensor for neurotransmitter sensing near neurons.

    Science.gov (United States)

    Lussier, Félix; Brulé, Thibault; Bourque, Marie-Josée; Ducrot, Charles; Trudeau, Louis-Éric; Masson, Jean-François

    2017-12-04

    Current electrophysiology and electrochemistry techniques have provided unprecedented understanding of neuronal activity. However, these techniques are suited to a small, albeit important, panel of neurotransmitters such as glutamate, GABA and dopamine, and these constitute only a subset of the broader range of neurotransmitters involved in brain chemistry. Surface-enhanced Raman scattering (SERS) provides a unique opportunity to detect a broader range of neurotransmitters in close proximity to neurons. Dynamic SERS (D-SERS) nanosensors based on patch-clamp-like nanopipettes decorated with gold nanoraspberries can be located accurately under a microscope using techniques analogous to those used in current electrophysiology or electrochemistry experiments. In this manuscript, we demonstrate that D-SERS can measure in a single experiment ATP, glutamate (glu), acetylcholine (ACh), GABA and dopamine (DA), among other neurotransmitters, with the potential for detecting a greater number of neurotransmitters. The SERS spectra of these neurotransmitters were identified with a barcoding data processing method and time series of the neurotransmitter levels were constructed. The D-SERS nanosensor was then located near cultured mouse dopaminergic neurons. The detection of neurotransmitters was performed in response to a series of K + depolarisations, and allowed the detection of elevated levels of both ATP and dopamine. Control experiments were also performed near glial cells, showing only very low basal detection neurotransmitter events. This paper demonstrates the potential of D-SERS to detect neurotransmitter secretion events near living neurons, but also constitutes a strong proof-of-concept for the broad application of SERS to the detection of secretion events by neurons or other cell types in order to study normal or pathological cell functions.

  11. Entre contener y ser contenido

    Directory of Open Access Journals (Sweden)

    Jorge Morales Meneses

    2016-08-01

    Full Text Available El presente artículo propone una nueva manera de entender los elementos comunes en la formación y el hacer del diseño y de la arquitectura, posibilitando un pensar común y un coactuar en diversas escalas de intervención, necesarias para el manejo de la complejidad del paisaje contemporáneo. La convicción de un pensar común entre ambas disciplinas permite explorar un marco filosófico que incluye a pensadores tan trascendentales como Aristóteles, Kant y Heidegger, estableciendo un orden de pensamiento que los relaciona y sitúa. En momentos en que el territorio está siendo visible y negativamente afectado por elementos no pensados o que fueron imaginados separadamente, este artículo propone una mirada que le dé sentido de totalidad a las acciones del diseño y de la arquitectura, como elementos que permanentemente se contienen en otros de diferente escala, pero que siempre están vinculados. Reconocer el paisaje físico y mental, tangible e intangible que contiene al diseño y a la arquitectura contribuirá a establecer un marco de acción donde todos los elementos construidos por el ser humano puedan tener un rol específico y una escala asumida, e intercomprenderse para mejor utilización de los recursos, disminuir el impacto ambiental y contribuir a un orden social mejor interpretado por los objetos, espacios y sus representaciones.

  12. Quaternized chitosan/silver nanoparticles composite as a SERS substrate for detecting tricyclazole and Sudan I

    International Nuclear Information System (INIS)

    Chen, Kaihang; Shen, Zuguang; Luo, Jiwen; Wang, Xiaoying; Sun, Runcang

    2015-01-01

    Graphical abstract: - Highlights: • Synthesis optimization of Ag NPs with quaternized chitosan (QCS) was studied. • The size of Ag NPs was tuned by changing the DS and Mw of QCS. • QCS/Ag NPs exhibited much better SERS performance than Ag NPs without free QCS. • QCS/Ag NPs as SERS substrate detected tricyclazole in low concentration of 50 ppb. • QCS/Ag NPs as SERS substrate detected Sudan I with the detection limit of 10 ppm. - Abstract: There is an urgent need to develop a highly sensitive detection system for detecting trace amounts of food contaminants. In this study, optimal synthesis of silver nanoparticles (Ag NPs) with stable and narrow size distribution in the range of 15–25 nm was performed under microwave irradiation, using quaternized chitosan (QCS) as reducing and stabilizing agent. The results showed that the ratio of QCS to [Ag(NH 3 ) 2 ] + , reaction temperature, irradiation time, the degree of substitution (DS) and molecular weight (Mw) of QCS had obvious effects on the formation, particle size and size distribution of Ag NPs. In addition, utilizing QCS/Ag NPs composite as SERS substrate, tricyclazole and Sudan I could be rapidly and sensitively detected with the limit of detection (LOD) as low as 50 ppb and 10 ppm, respectively. Compared with previously reported works, our detection system are of great stability and operability. The QCS was coated on the surface of Ag core, avoiding aggregation of Ag NPs and creating hot spots, in turn, providing superior amplification of SERS. Thus, it is believed that the QCS/Ag NPs composite could be considered as an ideal SERS-active substrate for detection of food contaminants

  13. Quaternized chitosan/silver nanoparticles composite as a SERS substrate for detecting tricyclazole and Sudan I

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kaihang; Shen, Zuguang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Jiwen, E-mail: holdit@126.com [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Xiaoying, E-mail: xyw@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Sun, Runcang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Institute of Biomass Chemistry and Technology, Beijing Forestry University, Beijing 100083 (China)

    2015-10-01

    Graphical abstract: - Highlights: • Synthesis optimization of Ag NPs with quaternized chitosan (QCS) was studied. • The size of Ag NPs was tuned by changing the DS and Mw of QCS. • QCS/Ag NPs exhibited much better SERS performance than Ag NPs without free QCS. • QCS/Ag NPs as SERS substrate detected tricyclazole in low concentration of 50 ppb. • QCS/Ag NPs as SERS substrate detected Sudan I with the detection limit of 10 ppm. - Abstract: There is an urgent need to develop a highly sensitive detection system for detecting trace amounts of food contaminants. In this study, optimal synthesis of silver nanoparticles (Ag NPs) with stable and narrow size distribution in the range of 15–25 nm was performed under microwave irradiation, using quaternized chitosan (QCS) as reducing and stabilizing agent. The results showed that the ratio of QCS to [Ag(NH{sub 3}){sub 2}]{sup +}, reaction temperature, irradiation time, the degree of substitution (DS) and molecular weight (Mw) of QCS had obvious effects on the formation, particle size and size distribution of Ag NPs. In addition, utilizing QCS/Ag NPs composite as SERS substrate, tricyclazole and Sudan I could be rapidly and sensitively detected with the limit of detection (LOD) as low as 50 ppb and 10 ppm, respectively. Compared with previously reported works, our detection system are of great stability and operability. The QCS was coated on the surface of Ag core, avoiding aggregation of Ag NPs and creating hot spots, in turn, providing superior amplification of SERS. Thus, it is believed that the QCS/Ag NPs composite could be considered as an ideal SERS-active substrate for detection of food contaminants.

  14. Achieving optimal SERS through enhanced experimental design.

    Science.gov (United States)

    Fisk, Heidi; Westley, Chloe; Turner, Nicholas J; Goodacre, Royston

    2016-01-01

    One of the current limitations surrounding surface-enhanced Raman scattering (SERS) is the perceived lack of reproducibility. SERS is indeed challenging, and for analyte detection, it is vital that the analyte interacts with the metal surface. However, as this is analyte dependent, there is not a single set of SERS conditions that are universal. This means that experimental optimisation for optimum SERS response is vital. Most researchers optimise one factor at a time, where a single parameter is altered first before going onto optimise the next. This is a very inefficient way of searching the experimental landscape. In this review, we explore the use of more powerful multivariate approaches to SERS experimental optimisation based on design of experiments and evolutionary computational methods. We particularly focus on colloidal-based SERS rather than thin film preparations as a result of their popularity. © 2015 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons, Ltd.

  15. Organelle-targeting surface-enhanced Raman scattering (SERS) nanosensors for subcellular pH sensing.

    Science.gov (United States)

    Shen, Yanting; Liang, Lijia; Zhang, Shuqin; Huang, Dianshuai; Zhang, Jing; Xu, Shuping; Liang, Chongyang; Xu, Weiqing

    2018-01-25

    The pH value of subcellular organelles in living cells is a significant parameter in the physiological activities of cells. Its abnormal fluctuations are commonly believed to be associated with cancers and other diseases. Herein, a series of surface-enhanced Raman scattering (SERS) nanosensors with high sensitivity and targeting function was prepared for the quantification and monitoring of pH values in mitochondria, nucleus, and lysosome. The nanosensors were composed of gold nanorods (AuNRs) functionalized with a pH-responsive molecule (4-mercaptopyridine, MPy) and peptides that could specifically deliver the AuNRs to the targeting subcellular organelles. The localization of our prepared nanoprobes in specific organelles was confirmed by super-high resolution fluorescence imaging and bio-transmission electron microscopy (TEM) methods. By the targeting ability, the pH values of the specific organelles can be determined by monitoring the vibrational spectral changes of MPy with different pH values. Compared to the cases of reported lysosome and cytoplasm SERS pH sensors, more accurate pH values of mitochondria and nucleus, which could be two additional intracellular tracers for subcellular microenvironments, were disclosed by this SERS approach, further improving the accuracy of discrimination of related diseases. Our sensitive SERS strategy can also be employed to explore crucial physiological and biological processes that are related to subcellular pH fluctuations.

  16. SERS substrates for in-situ biosensing (Conference Presentation)

    Science.gov (United States)

    Venugopalan, Priyamvada; Quilis, Nestor; Jakub, Dostalek; Wolfgang, Knoll

    2017-06-01

    Abstract: Recent years have seen a rapid progress in the field of surface-enhanced Raman spectroscopy (SERS) which is attributed to the thriving field of plasmonics [1]. SERS is a susceptible technique that can address basic scientific questions and technological problems. In both cases, it is highly dependent upon the plasmonic substrate, where excitation of the localized surface plasmon resonance enhances the vibrational scattering signal of the analyte molecules adsorbed on to the surface [2]. In this work, using finite difference time domain (FDTD) method we investigate the optical properties of plasmonic nanostructures with tuned plasmonic resonances as a function of dielectric environment and geometric parameters. An optimized geometry will be discussed based on the plasmonic resonant position and the SERS intensity. These SERS substrates will be employed for the detection of changes in conformation caused by interactions between an aptamer and analyte molecules. This will be done by using a microfluidic channel designed within the configuration of the lab-on-a-chip concept based on the intensity changes of the SERS signal. More efficient and reproducible results are obtained for such a quantitative measurement of analytes at low concentration levels. We will also demonstrate that the plasmonic substrates fabricated by top down approach such as e-beam lithography (EBL) and laser interference lithography (LIL) are highly reproducible, robust and can result in high electric field enhancement. Our results demonstrate the potential to use SERS substrates for highly sensitive detection schemes opening up the window for a wide range of applications including biomedical diagnostics, forensic investigation etc. Acknowledgement: This work was supported by the Austrian Science Fund (FWF), project NANOBIOSENSOR (I 2647). References: [1] J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao and R. P. V. Duyne., " Biosensing with plasmonic nanosensors," Nature

  17. Porous Silicon Covered with Silver Nanoparticles as Surface-Enhanced Raman Scattering (SERS) Substrate for Ultra-Low Concentration Detection.

    Science.gov (United States)

    Kosović, Marin; Balarin, Maja; Ivanda, Mile; Đerek, Vedran; Marciuš, Marijan; Ristić, Mira; Gamulin, Ozren

    2015-12-01

    Microporous and macro-mesoporous silicon templates for surface-enhanced Raman scattering (SERS) substrates were produced by anodization of low doped p-type silicon wafers. By immersion plating in AgNO3, the templates were covered with silver metallic film consisting of different silver nanostructures. Scanning electron microscopy (SEM) micrographs of these SERS substrates showed diverse morphology with significant difference in an average size and size distribution of silver nanoparticles. Ultraviolet-visible-near-infrared (UV-Vis-NIR) reflection spectroscopy showed plasmonic absorption at 398 and 469 nm, which is in accordance with the SEM findings. The activity of the SERS substrates was tested using rhodamine 6G (R6G) dye molecules and 514.5 nm laser excitation. Contrary to the microporous silicon template, the SERS substrate prepared from macro-mesoporous silicon template showed significantly broader size distribution of irregular silver nanoparticles as well as localized surface plasmon resonance closer to excitation laser wavelength. Such silver morphology has high SERS sensitivity that enables ultralow concentration detection of R6G dye molecules up to 10(-15) M. To our knowledge, this is the lowest concentration detected of R6G dye molecules on porous silicon-based SERS substrates, which might even indicate possible single molecule detection.

  18. High activity gamma irradiators developed in Hungary

    International Nuclear Information System (INIS)

    Stenger, V.

    1997-01-01

    The development of high activity Gamma irradiators began in Hungary already in the early years of 60s. The very first designs were serving research in irradiation chemistry, radiation physics, food and agricultural research, radiation sterilization, plastic radiation chemistry, radiobiology, cancer therapy, personal and high dose dosimetry, following the international trends. Domestic and new international demands forced us to design and construct High Activity Gamma Irradiators: Multipurpose Pilot, Portable and Large scale bulk, Multipurpose Industrial scale types

  19. Study of pyruvate decarboxylase and thiamine kinase from brewer's yeast by SERS

    Science.gov (United States)

    Maskevich, Sergei A.; Chernikevich, Ivan P.; Gachko, Gennedy A.; Kivach, Leonid N.; Strekal, Nataliya D.

    1993-06-01

    The Surface Enhanced Raman Scattering (SERS) spectra of holopyruvate decarboxylase (PDC) and thiamine kinase (ThK) adsorbed on silver electrode were obtained. In contrast to the Raman, the SERS spectrum of PDC contained no modes of tryptophan residues, it indicates a removal of this moiety from the surface. In the SERS spectrum of ThK the bands belonging to ligands bound to the protein were observed. A correlation between the SERS signal intensity and the enzymatic activity of the ThK separate fraction and found. The influence of amino acids on SERS spectra of thiamine (Th) was studied to determine the possible composition on microsurrounding of coenzyme.

  20. SERS study of surface plasmon resonance induced carrier movement in Au@Cu2O core-shell nanoparticles

    Science.gov (United States)

    Chen, Lei; Zhang, Fan; Deng, Xin-Yu; Xue, Xiangxin; Wang, Li; Sun, Yantao; Feng, Jing-Dong; Zhang, Yongjun; Wang, Yaxin; Jung, Young Mee

    2018-01-01

    A plasmon induced carrier movement enhanced mechanism of surface-enhanced Raman scattering (SERS) was investigated using a charge-transfer (CT) enhancement mechanism. Here, we designed a strategy to study SERS in Au@Cu2O nanoshell nanoparticles with different shell thicknesses. Among the plasmonically coupled nanostructures, Au spheres with Cu2O shells have been of special interest due to their ultrastrong electromagnetic fields and controllable carrier transfer properties, which are useful for SERS. Au@Cu2O nanoshell nanoparticles (NPs) with shell thicknesses of 48-56 nm are synthesized that exhibit high SERS activity. This high activity originates from plasmonic-induced carrier transfer from Au@Cu2O to 4-mercaptobenzoic acid (MBA). The CT transition from the valence band (VB) of Cu2O to the second excited π-π* transition of MBA, and is of b2 electronic symmetry, which was enhanced significantly. The Herzberg-Teller selection rules were employed to predict the observed enhanced b2 symmetry modes. The system constructed in this study combines the long-range electromagnetic effect of Au NPs, localized surface plasmon resonance (LSPR) of the Au@Cu2O nanoshell, and the CT contribution to assist in understanding the SERS mechanism based on LSPR-induced carrier movement in metal/semiconductor nanocomposites.

  1. Plasmonic crystal based solid substrate for biomedical application of SERS

    Science.gov (United States)

    Morasso, Carlo F.; Mehn, Dora; Picciolini, Silvia; Vanna, Renzo; Bedoni, Marzia; Gramatica, Furio; Pellacani, Paola; Frangolho, Ana; Marchesini, Gerardo; Valsesia, Andrea

    2014-02-01

    Surface Enhanced Raman Spectroscopy is a powerful analytical technique that combines the excellent chemical specificity of Raman spectroscopy with the good sensitivity provided by the enhancement of the signal observed when a molecule is located on (or very close to) the surface of suitable nanostructured metallic materials. The availability of cheap, reliable and easy to use SERS substrates would pave the road to the development of bioanalytical tests that can be used in clinical practice. SERS, in fact, is expected to provide not only higher sensitivity and specificity, but also the simultaneous and markedly improved detection of several targets at the same time with higher speed compared to the conventional analytical methods. Here, we present the SERS activity of 2-D plasmonic crystals made by polymeric pillars embedded in a gold matrix obtained through the combination of soft-lithography and plasma deposition techniques on a transparent substrates. The use of a transparent support material allowed us to perform SERS detection from support side opening the possibility to use these substrates in combination with microfluidic devices. In order to demonstrate the potentialities for bioanalytical applications, we used our SERS active gold surface to detect the oxidation product of apomorphine, a well-known drug molecule used in Parkinson's disease which has been demonstrated being difficult to study by traditional HPLC based approaches.

  2. SERS Technique for Rapid Bacterial Screening

    Science.gov (United States)

    This study reports the feasibility of citrate-reduced colloidal silver SERS for differentiating E. coli, Listeria, and Salmonella. FT-Raman and SERS spectra of both silver colloids and colloid-K3PO4 mixtures were collected and analyzed to evaluate the reproducibility and stability of silver colloids...

  3. A Gly482Ser missense mutation in the peroxisome proliferator-activated receptor gamma coactivator-1 is associated with altered lipid oxidation and early insulin secretion in Pima Indians

    DEFF Research Database (Denmark)

    Muller, Yunhua Li; Bogardus, Clifton; Pedersen, Oluf

    2003-01-01

    of the PGC-1 gene predicts a glycine to serine substitution at amino acid 482 and has been associated with type 2 diabetes in a Danish population. In this study, we examined whether this Gly482Ser polymorphism is associated with type 2 diabetes or obesity, or metabolic predictors of these diseases, in Pima...... Indians. There was no association of the Gly482Ser polymorphism with either type 2 diabetes or BMI (n = 984). However, among nondiabetic Pima Indians (n = 183-201), those with the Gly/Gly genotype had a lower mean insulin secretory response to intravenous and oral glucose and a lower mean rate of lipid...

  4. Studies of the Gly482Ser polymorphism of the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) gene in Danish subjects with the metabolic syndrome

    DEFF Research Database (Denmark)

    Ambye, Louise; Rasmussen, Susanne; Fenger, Mogens

    2005-01-01

    related to this syndrome. The variant was examined, using PCR-RFLP, in the DanMONICA cohort comprising a population-based sample of 2349 subjects. MS was defined using the National Cholesterol Education Program -- Adult Treatment Panel III (NCEP-ATPIII) criteria. The allelic frequency of the Ser482 allele...... and insulin secretion, 24-ambulatory blood pressure or left ventricular mass index. In conclusion, the Gly482Ser polymorphism of the PGC-1alpha gene is not associated with the metabolic syndrome, related quantitative traits or cardiac hypertrophy among Danish Caucasian subjects...

  5. SERS-based pesticide detection by using nanofinger sensors

    Science.gov (United States)

    Kim, Ansoon; Barcelo, Steven J.; Li, Zhiyong

    2015-01-01

    Simple, sensitive, and rapid detection of trace levels of extensively used and highly toxic pesticides are in urgent demand for public health. Surface-enhanced Raman scattering (SERS)-based sensor was designed to achieve ultrasensitive and simple pesticide sensing. We developed a portable sensor system composed of high performance and reliable gold nanofinger sensor strips and a custom-built portable Raman spectrometer. Compared to the general procedure and previously reported studies that are limited to laboratory settings, our analytical method is simple, sensitive, rapid, and cost-effective. Based on the SERS results, the chemical interaction of two pesticides, chlorpyrifos (CPF) and thiabendazole (TBZ), with gold nanofingers was studied to determine a fingerprint for each pesticide. The portable SERS-sensor system was successfully demonstrated to detect CPF and TBZ pesticides within 15 min with a detection limit of 35 ppt in drinking water and 7 ppb on apple skin, respectively.

  6. SERS-Based Prognosis of Kidney Transplant Outcome

    Science.gov (United States)

    Chi, Jingmao

    Kidney transplant is the predominant procedure of all organ transplants around the world. The number of patients on the waiting list for a kidney is growing rapidly, yet the number of donations does not keep up with the fast-growing need. This thesis focuses on the surface-enhanced Raman scattering (SERS) analysis of urine samples for prognosis of kidney transplant outcome, which can potentially let patients have a more timely treatment as well as expand the organ pool for transplant. We have observed unique SERS spectral features from urine samples of kidney transplant recipients that have strong associations with the kidney acute rejection (AR) based on the analysis of urine one day after the transplant. Our ability to provide an early prognosis of transplant outcome is a significant advance over the current gold standard of clinical diagnosis, which occurs weeks or months after the surgical procedure. The SERS analysis has also been applied to urine samples from deceased kidney donors. Excellent classification ability was achieved when the enhanced PCA-LDA analysis was used to classify and identify urine samples from different cases. The sensitivity of the acute tubular necrosis (ATN) class is more than 90%, which can indicate the usable kidneys in the high failure risk category. This analysis can help clinicians identify usable kidneys which would be discarded using conventional clinic methods as high failure risk. To investigate the biomarkers that cause the unique SERS features, an HPLC-SERS-MS approach was established. The high-performance liquid chromatography (HPLC) was used to separate the urinary components to reduce the sample complexity. The mass spectrometry (MS) was used to determine the formulas and the structures of the biomarkers. The presence of 1-methyl-2-pyrrolidone (NMP) and adenine in urine samples were confirmed by both MS and SERS analysis. Succinylmonocholine, a metabolite of suxamethonium, has a potential to be the biomarker that causes

  7. Fabrication of SERS Substrate by Multilayered Nanosphere Deposition Technique

    International Nuclear Information System (INIS)

    Fu, Chit Yaw; Dinish, U. S.; Praveen, Thoniyot; Koh, Zhen Yu; Kho, Khiang Wei; Malini, Olivo

    2010-01-01

    Metal film over nanosphere (MFON) has been employed as a reproducible and predictable SERS-active device in biosensing applications. In addition to its economic fabrication process, such substrate can be further processed to a prism-structure with increased SERS enhancement and wider Plasmon tunability. In this work, we investigate an alternative coating method to deposit a larger area of well-ordered PS beads with different sizes (oe = 100nm and 400 nm) onto a glass. The result suggests that the proposed well-coating technique can be suitably used to form closely-packed PS beads with diameter less than 100 nm for developing MFON substrates.

  8. New nanocomposites for SERS studies of living cells and mitochondria

    DEFF Research Database (Denmark)

    Sarycheva, A. S.; Brazhe, N. A.; Baizhumanov, A. A.

    2016-01-01

    A great enhancement in Raman scattering (SERS) from heme-containing submembrane biomolecules inside intact erythrocytes and functional mitochondria is demonstrated for the first time using silver–silica beads prepared using a new method involving aerosol pyrolysis with aqueous diamminesilver...... molecules. The SERS spectra of functional mitochondria are sensitive to the activity of the mitochondrial electron transport chain, thus making the method a novel label-free approach to monitor the redox state and conformation of cytochromes in their natural cell environment. The developed nanocomposites...

  9. Normal Raman and SERS spectroscopy of the vitamin E

    International Nuclear Information System (INIS)

    Cai Tiantian; Gu Huaimin; Yuan Xiaojuan; Liu Fangfang

    2011-01-01

    In this study, surface-enhanced Raman scattering(SERS)spectra of vitamin E were obtained on colloidal silver(Ag). Alpha-(-) tocopherol which is the only form that is recognized to meet human requirements was selected to study. The analytes (±)- -tocopherol were dissolved in chloroform (CHCl 3 ) and the silver colloid was poured into the compound. Silver colloid was reduced by hydroxylamine hydrochloride. The analytes were the supernatant after standing the mixture for the reason that chloroform have no signals in surface-enhanced Raman scattering in the Ag colloid, and it would not affect the determination of the (±)- -tocopherol. The Normal Raman and SERS spectrum of Vitamin E were contrastively studied to realize how the vitamin E stuck to the silver nanoparticles. The results show the fat-soluble substances can be analysed by SERS. The spectra indicate that the molecules are adsorbed on the surface through the COO- groups by the simultaneous involvement of a and -type coordination. These results suggest some important criteria for consideration in SERS measurements and also provide important insights into the problem of predicting SERS activities for different fat-soluble substances.

  10. Normal Raman and SERS spectroscopy of the vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Cai Tiantian; Gu Huaimin; Yuan Xiaojuan; Liu Fangfang, E-mail: guhm@scnu.edu.cn [MOE Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, 510631, Guangzhou (China)

    2011-01-01

    In this study, surface-enhanced Raman scattering(SERS)spectra of vitamin E were obtained on colloidal silver(Ag). Alpha-(-) tocopherol which is the only form that is recognized to meet human requirements was selected to study. The analytes ({+-})- -tocopherol were dissolved in chloroform (CHCl{sub 3}) and the silver colloid was poured into the compound. Silver colloid was reduced by hydroxylamine hydrochloride. The analytes were the supernatant after standing the mixture for the reason that chloroform have no signals in surface-enhanced Raman scattering in the Ag colloid, and it would not affect the determination of the ({+-})- -tocopherol. The Normal Raman and SERS spectrum of Vitamin E were contrastively studied to realize how the vitamin E stuck to the silver nanoparticles. The results show the fat-soluble substances can be analysed by SERS. The spectra indicate that the molecules are adsorbed on the surface through the COO- groups by the simultaneous involvement of a and -type coordination. These results suggest some important criteria for consideration in SERS measurements and also provide important insights into the problem of predicting SERS activities for different fat-soluble substances.

  11. Intracellular surface-enhanced Raman scattering (SERS) with thermally stable gold nanoflowers grown from Pt and Pd seeds

    KAUST Repository

    Song, Hyon Min

    2013-01-01

    SERS provides great sensitivity at low concentrations of analytes. SERS combined with near infrared (NIR)-resonant gold nanomaterials are important candidates for theranostic agents due to their combined extinction properties and sensing abilities stemming from the deep penetration of laser light in the NIR region. Here, highly branched gold nanoflowers (GNFs) grown from Pd and Pt seeds are prepared and their SERS properties are studied. The growth was performed at 80°C without stirring, and this high temperature growth method is assumed to provide great shape stability of sharp tips in GNFs. We found that seed size must be large enough (>30 nm in diameter) to induce the growth of those SERS-active and thermally stable GNFs. We also found that the addition of silver nitrate (AgNO3) is important to induce sharp tip growth and shape stability. Incubation with Hela cells indicates that GNFs are taken up and reside in the cytoplasm. SERS was observed in those cells incubated with 1,10-phenanthroline (Phen)-loaded GNFs. This journal is © 2013 The Royal Society of Chemistry.

  12. Intracellular surface-enhanced Raman scattering (SERS) with thermally stable gold nanoflowers grown from Pt and Pd seeds.

    Science.gov (United States)

    Song, Hyon Min; Deng, Lin; Khashab, Niveen M

    2013-05-21

    SERS provides great sensitivity at low concentrations of analytes. SERS combined with near infrared (NIR)-resonant gold nanomaterials are important candidates for theranostic agents due to their combined extinction properties and sensing abilities stemming from the deep penetration of laser light in the NIR region. Here, highly branched gold nanoflowers (GNFs) grown from Pd and Pt seeds are prepared and their SERS properties are studied. The growth was performed at 80 °C without stirring, and this high temperature growth method is assumed to provide great shape stability of sharp tips in GNFs. We found that seed size must be large enough (>30 nm in diameter) to induce the growth of those SERS-active and thermally stable GNFs. We also found that the addition of silver nitrate (AgNO3) is important to induce sharp tip growth and shape stability. Incubation with Hela cells indicates that GNFs are taken up and reside in the cytoplasm. SERS was observed in those cells incubated with 1,10-phenanthroline (Phen)-loaded GNFs.

  13. Produção de substratos sers eficientes através da deposição de ouro sobre um molde de microesferas de poliestireno Production of efficient sers substrates by depositing gold over a polystyrene beads template

    Directory of Open Access Journals (Sweden)

    Diego Pereira dos Santos

    2010-01-01

    Full Text Available This work reports on the SERS activity of a nanostructured substrate that was obtained by electrodepositing gold over a template consisting of polystyrene microspheres. This substrate displayed superior SERS performance for the detection of 4-merctaptopyridine as compared to a conventional roughened Au electrode. In order to investigate the substrate capability for the detection at low concentration limits, a series of Rhodamine 6G (1 nM spectra were registered. Our spectral dynamics data is in agreement with single-molecule behavior, showing that the control over the substrate morphology is crucial to enable the production of highly reproducible and sensitive SERS substrates.

  14. Correlative SEM SERS for quantitative analysis of dimer nanoparticles.

    Science.gov (United States)

    Timmermans, F J; Lenferink, A T M; van Wolferen, H A G M; Otto, C

    2016-11-14

    A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

  15. In Vitro and In Vivo SERS Biosensing for Disease Diagnosis

    Directory of Open Access Journals (Sweden)

    T. Joshua Moore

    2018-05-01

    Full Text Available For many disease states, positive outcomes are directly linked to early diagnosis, where therapeutic intervention would be most effective. Recently, trends in disease diagnosis have focused on the development of label-free sensing techniques that are sensitive to low analyte concentrations found in the physiological environment. Surface-enhanced Raman spectroscopy (SERS is a powerful vibrational spectroscopy that allows for label-free, highly sensitive, and selective detection of analytes through the amplification of localized electric fields on the surface of a plasmonic material when excited with monochromatic light. This results in enhancement of the Raman scattering signal, which allows for the detection of low concentration analytes, giving rise to the use of SERS as a diagnostic tool for disease. Here, we present a review of recent developments in the field of in vivo and in vitro SERS biosensing for a range of disease states including neurological disease, diabetes, cardiovascular disease, cancer, and viral disease.

  16. Surface-enhanced Raman scattering (SERS) for detection of phenylketonuria for newborn screening

    Science.gov (United States)

    Javanmard, M.; Davis, R. W.

    2014-02-01

    Diagnosis of Phenylketonuria (PKU) in newborns is important because it can potentially help prevent mental retardation since it is treatable by dietary means. PKU results in phenylketonurics having phenylalanine levels as high as 2 mM whereas the normal upper limit in healthy newborns is 120 uM. To this end, we are developing a microfluidic platform integrated with a SERS substrate for detection of high levels of phenylalanine. We have successfully demonstrated SERS detection of phenylalanine using various SERS substrates fabricated using nanosphere lithography, which exhibit high levels of field enhancement. We show detection of SERS at clinically relevant levels.

  17. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    Hochel, R.C.

    1979-01-01

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other trace elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  18. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    Hochel, R.C.; Bowman, W.W.; Zeh, C.W.

    1980-01-01

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program, which is sponsored and funded by the United States Department of Energy, Grand Junction Office. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  19. Engineering Metal Nanostructure for SERS Application

    Directory of Open Access Journals (Sweden)

    Yanqin Cao

    2013-01-01

    Full Text Available Surface-enhanced Raman scattering (SERS has attracted great attention due to its remarkable enhancement and excellent selectivity in the detection of various molecules. Noble metal nanomaterials have usually been employed for producing substrates that can be used in SERS because of their unique local plasma resonance. As the SERS enhancement of signals depends on parameters such as size, shape, morphology, arrangement, and dielectric environment of the nanostructure, there have been a number of studies on tunable nanofabrication and synthesis of noble metals. In this work, we will illustrate progress in engineering metallic nanostructures with various morphologies using versatile methods. We also discuss their SERS applications in different fields and the challenges.

  20. Enclosure for handling high activity materials

    International Nuclear Information System (INIS)

    Jimeno de Osso, F.

    1977-01-01

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

  1. Enclosure for handling high activity materials abstract

    International Nuclear Information System (INIS)

    Jimeno de Osso, F.; Dominguez Rodriguez, G.; Cruz Castillo, F. de la; Rodriguez Esteban, A.

    1977-01-01

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With that purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. A description is given of those aspects that may be of interest to people working in this field. (author) [es

  2. Enclosure for handling high activity materials

    Energy Technology Data Exchange (ETDEWEB)

    Jimeno de Osso, F

    1977-07-01

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

  3. Single molecule SERS: Perspectives of analytical applications

    Czech Academy of Sciences Publication Activity Database

    Vlčková, B.; Pavel, I.; Sládková, M.; Šišková, K.; Šlouf, Miroslav

    834-836, - (2007), s. 42-47 ISSN 0022-2860. [European Congress on Molecular Spectroscopy /28./. Istanbul, 03.09.2006-08.09.2006] R&D Projects: GA ČR GA203/04/0688 Institutional research plan: CEZ:AV0Z40500505 Keywords : surface-enhanced Raman scattering (SERS) * surface-enhanced resonance Raman (SERRS) * single molecule SERS Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.486, year: 2007

  4. Management of synchronized network activity by highly active neurons

    International Nuclear Information System (INIS)

    Shein, Mark; Raichman, Nadav; Ben-Jacob, Eshel; Volman, Vladislav; Hanein, Yael

    2008-01-01

    Increasing evidence supports the idea that spontaneous brain activity may have an important functional role. Cultured neuronal networks provide a suitable model system to search for the mechanisms by which neuronal spontaneous activity is maintained and regulated. This activity is marked by synchronized bursting events (SBEs)—short time windows (hundreds of milliseconds) of rapid neuronal firing separated by long quiescent periods (seconds). However, there exists a special subset of rapidly firing neurons whose activity also persists between SBEs. It has been proposed that these highly active (HA) neurons play an important role in the management (i.e. establishment, maintenance and regulation) of the synchronized network activity. Here, we studied the dynamical properties and the functional role of HA neurons in homogeneous and engineered networks, during early network development, upon recovery from chemical inhibition and in response to electrical stimulations. We found that their sequences of inter-spike intervals (ISI) exhibit long time correlations and a unimodal distribution. During the network's development and under intense inhibition, the observed activity follows a transition period during which mostly HA neurons are active. Studying networks with engineered geometry, we found that HA neurons are precursors (the first to fire) of the spontaneous SBEs and are more responsive to electrical stimulations

  5. Self-assembly Ag nanoparticle monolayer film as SERS Substrate for pesticide detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li, E-mail: zhlisuzh@163.com [School of Chemistry and Life Science, Anhui Key Laboratory of Spin Electron and Nanomaterials (Cultivating Base), Suzhou University, SuZhou 234000 (China)

    2013-04-01

    A self-assembled protocol is introduced to provide effective platforms for the fabrication of ordered Ag nanosized monolayer film. The assembled Ag nanosized monolayer film was characterized using scanning electronic microscopy and surface-enhanced Raman scattering (SERS). The results show that the assembled SERS substrate own excellent Raman enhancement and reproducibility. The synthesized SERS-active substrate was further used to detect methyl-parathion, and the limitation of detection can reach 10{sup −7} M.

  6. In vitro antioxidant activities of the novel pentapeptides Ser-His-Glu-Cys-Asn and Leu-Pro-Phe-Ala-Met and the relationship between activity and peptide secondary structure

    DEFF Research Database (Denmark)

    Yang, Ruiwen; Wang, Jia; Lin, Songyi

    2017-01-01

    ,5-diphenyltetrazolium bromide] assay was used to evaluate cytotoxicity in HepG2 cells. Antioxidant activity was measured using in vitro assays, including the cellular antioxidant activity assay (CAA), 2,2-diphenyl-1-picrylhydrazyl or 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS...... LPFAM (P ABTS inhibition (88.16 ± 0.76%). It had normalized ORAC values of 0.3000 ± 0.0070 µmol GE mg(-1) and 0.0900 ± 0.0020 µmol TE mg(-1) , respectively. The results...

  7. Superhydrophobic SERS substrates based on silicon hierarchical nanostructures

    Science.gov (United States)

    Chen, Xuexian; Wen, Jinxiu; Zhou, Jianhua; Zheng, Zebo; An, Di; Wang, Hao; Xie, Weiguang; Zhan, Runze; Xu, Ningsheng; Chen, Jun; She, Juncong; Chen, Huanjun; Deng, Shaozhi

    2018-02-01

    Silicon nanostructures have been cultivated as promising surface enhanced Raman scattering (SERS) substrates in terms of their low-loss optical resonance modes, facile functionalization, and compatibility with today’s state-of-the-art CMOS techniques. However, unlike their plasmonic counterparts, the electromagnetic field enhancements induced by silicon nanostructures are relatively small, which restrict their SERS sensing limit to around 10-7 M. To tackle this problem, we propose here a strategy for improving the SERS performance of silicon nanostructures by constructing silicon hierarchical nanostructures with a superhydrophobic surface. The hierarchical nanostructures are binary structures consisted of silicon nanowires (NWs) grown on micropyramids (MPs). After being modified with perfluorooctyltriethoxysilane (PFOT), the nanostructure surface shows a stable superhydrophobicity with a high contact angle of ˜160°. The substrate can allow for concentrating diluted analyte solutions into a specific area during the evaporation of the liquid droplet, whereby the analytes are aggregated into a small volume and can be easily detected by the silicon nanostructure SERS substrate. The analyte molecules (methylene blue: MB) enriched from an aqueous solution lower than 10-8 M can be readily detected. Such a detection limit is ˜100-fold lower than the conventional SERS substrates made of silicon nanostructures. Additionally, the detection limit can be further improved by functionalizing gold nanoparticles onto silicon hierarchical nanostructures, whereby the superhydrophobic characteristics and plasmonic field enhancements can be combined synergistically to give a detection limit down to ˜10-11 M. A gold nanoparticle-functionalized superhydrophobic substrate was employed to detect the spiked melamine in liquid milk. The results showed that the detection limit can be as low as 10-5 M, highlighting the potential of the proposed superhydrophobic SERS substrate in

  8. Instaurando maneiras de ser, conhecer e interpretar

    Directory of Open Access Journals (Sweden)

    Maria Stephanou

    1998-01-01

    Full Text Available O artigo propõe a discussão e a problematização do tema "currículo e história". Na primeira parte explicita os fundamentos propostos para a abordagem, as concepções de currículo e história. Na segunda, privilegia as indicações de autores e a experiência pessoal para: a caracterizar o que têm sido os currículos e o ensino de história, particularmente no ensino fundamental, comentan-do suas implicações; b examinar alternativas e encaminhamentos propostos pelos debates da atualidade. Sugere que a aprendizagem de conteúdos históricos na escola, para além da mera aquisição de informações, implica a produção ativa de subjetividades, ou maneiras de ser, conhecer e interpretar o mundo e a si próprio.This article proposes to discuses and to question the theme "curriculum & history". On first part, it explains the fundaments proposed to the dissertation, the conception of curriculum & history. On the second, it grants privilege upon authors remarks and personal experience for purpose to: a characterize what were the curricular activities and the teaching of history, inside primary school particularly, with comments about its implications. b examine alternatives and forwarding proposed by present debates. It suggests that in the school the apprenticeship around historical contents, other than a pure acquisition of information, implies and actives production of subjectivities or manners of being, knowing and interpreting the world and oneself.

  9. Perceived stigma and highly active antiretroviral treatment ...

    African Journals Online (AJOL)

    Perceived stigma and highly active antiretroviral treatment adherence among persons living with HIV/AIDS in the University of Port Harcourt Teaching Hospital. ... Data on socio-demographic characteristics, stigma and adherence to drug regimen were collected using a validated self-administered questionnaire. Data were ...

  10. Disposal of high-activity nuclear wastes

    International Nuclear Information System (INIS)

    Hamilton, E.I.

    1983-01-01

    A discussion is presented on the deep sea ocean disposal for high-activity nuclear wastes. The following topics are covered: effect of ionizing radiation on marine ecosystems; pathways by which radionuclides are transferred to man from the marine environment; information about releases of radioactivity to the sea; radiological protection; storage and disposal of radioactive wastes and information needs. (U.K.)

  11. High-activity liquid packaging design criteria

    International Nuclear Information System (INIS)

    1994-05-01

    In recent studies, it has been acknowledged that there is an emerging need for packaging to transport high-activity liquid off the Hanford Site to support characterization and process development activities of liquid waste stored in underground tanks. These studies have dealt with specimen testing needs primarily at the Hanford Site; however, similar needs appear to be developing at other US Department of Energy (DOE) sites. The need to ship single and multiple specimens to offsite laboratories is anticipated because it is predicted that onsite laboratories will be overwhelmed by an increasing number and size (volume) of samples. Potentially, the specimen size could range from 250 mL to greater than 50 L. Presently, no certified Type-B packagings are available for transport of high-activity liquid radioactive specimens in sizes to support Site missions

  12. Conocer y ser en el paradigma constructivista

    Directory of Open Access Journals (Sweden)

    Jose Antonio Camargo Rodriguez

    2014-03-01

    Full Text Available Toda teoría acerca del aprendizaje se fundamenta en una interpretación del conocimiento, la cual se encuentra, a su vez, ligada a una cierta concepción de «ser». No será posible asimilar verdaderamente cualquiera de tales teorías si se ignoran, o no se consideran con el debido detenimiento, las ideas de conocer y «ser» que le sirven de base. Sc pone de presente que el constructivismo, en contraste con la teoría transmisionista de la enseñanza y el aprendizaje, predominante en la pedagogía tradicional, tiene su fundamento en la interpretación según la cual el conocer es una actividad humana en la que, a medida quo conoce, el hombre construye el «ser». Antes de todo conocimiento, las cosas no tienen un «ser»; están ahí, pero no se sabe lo que son. El «ser», quo constituye el objeto de todo conocer, aquello que el sujeto persigue a través de su conocimiento, no toes dada de antemano, ni le viene de fuera, sino quo es una elaboración quo el mismo realiza a través de su actividad cognoscitiva, un contenido de su propia conciencia. Hay, pues, una cierta paradoja entre las ideas de conocer y «ser» que sirven de fundamento al constructivismo, cuya reflexión se propone en aras de ganar una mejor comprensión, de encontrarle a este paradigma un sentido más allá de la pedagogía y la didáctica.

  13. High activity carbon sorbents for mercury capture

    Directory of Open Access Journals (Sweden)

    Stavropoulos George G.

    2006-01-01

    Full Text Available High efficiency activated carbons have been prepared for removing mercury from gas streams. Starting materials used were petroleum coke, lignite, charcoal and olive seed waste, and were chemically activated with KOH. Produced adsorbents were primarily characterized for their porosity by N2 adsorption at 77 K. Their mercury retention capacity was characterized based on the breakthrough curves. Compared with typical commercial carbons, they have exhibited considerably enhanced mercury adsorption capacity. An attempt has been made to correlate mercury entrapment and pore structure. It has been shown that physical surface area is increased during activation in contrast to the mercury adsorption capacity that initially increases and tends to decrease at latter stages. Desorption of active sites may be responsible for this behavior.

  14. IAEA high temperature gas cooled reactor activities

    International Nuclear Information System (INIS)

    Kendall, J.M.

    2001-01-01

    IAEA activities on high temperature gas cooled reactors are conducted with the review and support of Member States, primarily through the International Working Group on Gas Cooled Reactors (IWGGCR). This paper summarises the results of the IAEA gas cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products, and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (author)

  15. Platelets retain high levels of active plasminogen activator inhibitor 1.

    Directory of Open Access Journals (Sweden)

    Helén Brogren

    Full Text Available The vascular fibrinolytic system is crucial for spontaneous lysis of blood clots. Plasminogen activator inhibitor 1 (PAI-1, the principal inhibitor of the key fibrinolytic enzyme tissue-type plasminogen activator (tPA, is present in platelets at high concentrations. However, the majority of PAI-1 stored in platelets has been considered to be inactive. Our recent finding (Brogren H, et al. Blood 2004 that PAI-1 de novo synthesized in platelets remained active for over 24 h, suggested that PAI-1 stored in the α-granules might be active to a larger extent than previously reported. To re-evaluate this issue, we performed experiments where the fraction of active PAI-1 was estimated by analyzing the tPA-PAI-1 complex formation. In these experiments platelets were lysed with Triton X-100 in the presence of serial dilutions of tPA and subsequently the tPA-PAI-1 complex was evaluated by Western blot. Also, using a non-immunologic assay, tPA was labeled with (125I, and (125I-tPA and (125I-tPA-PAI-1 was quantified by scintigraphy. Interestingly, both methods demonstrated that the majority (>50% of platelet PAI-1 is active. Further analyses suggested that pre-analytical procedures used in previous studies (sonication or freezing/thawing may have substantially reduced the activity of platelet PAI-1, which has lead to an underestimation of the proportion of active PAI-1. Our in vitro results are more compatible with the role of PAI-1 in clot stabilization as demonstrated in physiological and pathophysiological studies.

  16. Detection and quantification of alternative splice sites in Arabidopsis genes AtDCL2 and AtPTB2 with highly sensitive surface enhanced Raman spectroscopy (SERS) and gold nanoprobes.

    Science.gov (United States)

    Kadam, Ulhas S; Schulz, Burkhard; Irudayaraj, Joseph

    2014-05-02

    Alternative splicing (AS) increases the size of the transcriptome and proteome to enhance the physiological capacity of cells. We demonstrate surface enhanced Raman spectroscopy (SERS) in combination with a DNA hybridization analytical platform to identify and quantify AS genes in plants. AS in AtDCL2 and AtPTB2 were investigated using non-fluorescent Raman probes using a 'sandwich assay'. Utilizing Raman probes conjugated to gold nanoparticles we demonstrate the recognition of RNA sequences specific to AtDCL2 and AtPTB2 splice junction variants with detection sensitivity of up to 0.1 fM. Published by Elsevier B.V.

  17. Early high-Tc commercial activity

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The high temperature superconductors have already begun to generate the first stirrings of commercial activity. Companies that supply instruments and chemicals to researchers have enjoyed increased business. At least one company has begun to supply educational materials. Venture capital firms have invested about $15 million in startups to capitalize on developments in high-field applications, superconducting electronics, and magnetic shielding. Consulting firms are gathering and selling market research information. And the federal government is studying the question of how to cooperate with American companies to commercialize the research taking place in the national laboratories. This article discusses these issues

  18. Production of high specific activity silicon-32

    International Nuclear Information System (INIS)

    Phillips, D.R.; Brzezinski, M.A.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development Project (LDRD) at Los Alamos National Laboratory (LANL). There were two primary objectives for the work performed under this project. The first was to take advantage of capabilities and facilities at Los Alamos to produce the radionuclide 32 Si in unusually high specific activity. The second was to combine the radioanalytical expertise at Los Alamos with the expertise at the University of California to develop methods for the application of 32 Si in biological oceanographic research related to global climate modeling. The first objective was met by developing targetry for proton spallation production of 32 Si in KCl targets and chemistry for its recovery in very high specific activity. The second objective was met by developing a validated field-useable, radioanalytical technique, based upon gas-flow proportional counting, to measure the dynamics of silicon uptake by naturally occurring diatoms

  19. Active vibration isolation of high precision machines

    CERN Document Server

    Collette, C; Artoos, K; Hauviller, C

    2010-01-01

    This paper provides a review of active control strategies used to isolate high precisionmachines (e.g. telescopes, particle colliders, interferometers, lithography machines or atomic force microscopes) from external disturbances. The objective of this review is to provide tools to develop the best strategy for a given application. Firstly, the main strategies are presented and compared, using single degree of freedom models. Secondly, the case of huge structures constituted of a large number of elements, like particle colliders or segmented telescopes, is considered.

  20. Wafer-Scale Hierarchical Nanopillar Arrays Based on Au Masks and Reactive Ion Etching for Effective 3D SERS Substrate

    Directory of Open Access Journals (Sweden)

    Dandan Men

    2018-02-01

    Full Text Available Two-dimensional (2D periodic micro/nanostructured arrays as SERS substrates have attracted intense attention due to their excellent uniformity and good stability. In this work, periodic hierarchical SiO2 nanopillar arrays decorated with Ag nanoparticles (NPs with clean surface were prepared on a wafer-scale using monolayer Au NP arrays as masks, followed by reactive ion etching (RIE, depositing Ag layer and annealing. For the prepared SiO2 nanopillar arrays decorated with Ag NPs, the size of Ag NPs was tuned from ca. 24 to 126 nanometers by controlling the deposition thickness of Ag film. Importantly, the SiO2 nanopillar arrays decorated with Ag NPs could be used as highly sensitive SERS substrate for the detection of 4-aminothiophenol (4-ATP and rhodamine 6G (R6G due to the high loading of Ag NPs and a very uniform morphology. With a deposition thickness of Ag layer of 30 nm, the SiO2 nanopillar arrays decorated with Ag NPs exhibited the best sensitive SERS activity. The excellent SERS performance of this substrate is mainly attributed to high-density “hotspots” derived from nanogaps between Ag NPs. Furthermore, this strategy might be extended to synthesize other nanostructured arrays with a large area, which are difficult to be prepared only via conventional wet-chemical or physical methods.

  1. Wafer-Scale Hierarchical Nanopillar Arrays Based on Au Masks and Reactive Ion Etching for Effective 3D SERS Substrate.

    Science.gov (United States)

    Men, Dandan; Wu, Yingyi; Wang, Chu; Xiang, Junhuai; Yang, Ganlan; Wan, Changjun; Zhang, Honghua

    2018-02-04

    Two-dimensional (2D) periodic micro/nanostructured arrays as SERS substrates have attracted intense attention due to their excellent uniformity and good stability. In this work, periodic hierarchical SiO₂ nanopillar arrays decorated with Ag nanoparticles (NPs) with clean surface were prepared on a wafer-scale using monolayer Au NP arrays as masks, followed by reactive ion etching (RIE), depositing Ag layer and annealing. For the prepared SiO₂ nanopillar arrays decorated with Ag NPs, the size of Ag NPs was tuned from ca. 24 to 126 nanometers by controlling the deposition thickness of Ag film. Importantly, the SiO₂ nanopillar arrays decorated with Ag NPs could be used as highly sensitive SERS substrate for the detection of 4-aminothiophenol (4-ATP) and rhodamine 6G (R6G) due to the high loading of Ag NPs and a very uniform morphology. With a deposition thickness of Ag layer of 30 nm, the SiO₂ nanopillar arrays decorated with Ag NPs exhibited the best sensitive SERS activity. The excellent SERS performance of this substrate is mainly attributed to high-density "hotspots" derived from nanogaps between Ag NPs. Furthermore, this strategy might be extended to synthesize other nanostructured arrays with a large area, which are difficult to be prepared only via conventional wet-chemical or physical methods.

  2. Surface modified gold nanoparticles for SERS based detection of vulnerable plaque formations (Conference Presentation)

    Science.gov (United States)

    Matthäus, Christian; Dugandžić, Vera; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2017-02-01

    Cardiovascular diseases are the leading cause of death worldwide. Atherosclerosis is closely related to the majority of these diseases, as a process of thickening and stiffening of the arterial walls through accumulation of lipids, which is a consequence of aging and life style. Atherosclerosis affects all people in some extent, but not all arterial plaques will necessarily lead to the complications, such as thrombosis, stroke and heart attack. One of the greatest challenges in the risk assessment of atherosclerotic depositions is the detection and recognition of plaques which are unstable and prone to rupture. These vulnerable plaques usually consist of a lipid core that attracts macrophages, a type of white blood cells that are responsible for the degradation of lipids. It has been hypothesized that the amount of macrophages relates to the overall plaque stability. As phagocytes, macrophages also act as recipients for nanoscale particles or structures. Administered gold nanoparticles are usually rabidly taken up by macrophages residing within arterial walls and can therefore be indirectly detected. A very sensitive strategy for probing gold nanoparticles is by utilizing surface enhanced Raman scattering (SERS). By modifying the surface of these particles with SERS active labels it is possible to generate highly specific signals that exhibit sensitivity comparable to fluorescence. SERS labeled gold nanoparticles have been synthesized and the uptake dynamics and efficiency on macrophages in cell cultures was investigated using Raman microscopic imaging. The results clearly show that nanoparticles are taken up by macrophages and support the potential of SERS spectroscopy for the detection of vulnerable plaques. Acknowledgements: Financial support from the Carl Zeiss Foundation is highly acknowledged. The project "Jenaer Biochip Initiative 2.0" (03IPT513Y) within the framework "InnoProfile Transfer - Unternehmen Region" is supported by the Federal Ministry of

  3. Neighboring phosphoSer-Pro motifs in the undefined domain of IRAK1 impart bivalent advantage for Pin1 binding.

    Science.gov (United States)

    Rogals, Monique J; Greenwood, Alexander I; Kwon, Jeahoo; Lu, Kun Ping; Nicholson, Linda K

    2016-12-01

    The peptidyl prolyl isomerase Pin1 has two domains that are considered to be its binding (WW) and catalytic (PPIase) domains, both of which interact with phosphorylated Ser/Thr-Pro motifs. This shared specificity might influence substrate selection, as many known Pin1 substrates have multiple sequentially close phosphoSer/Thr-Pro motifs, including the protein interleukin-1 receptor-associated kinase-1 (IRAK1). The IRAK1 undefined domain (UD) contains two sets of such neighboring motifs (Ser131/Ser144 and Ser163/Ser173), suggesting possible bivalent interactions with Pin1. Using a series of NMR titrations with 15N-labeled full-length Pin1 (Pin1-FL), PPIase, or WW domain and phosphopeptides representing the Ser131/Ser144 and Ser163/Ser173 regions of IRAK1-UD, bivalent interactions were investigated. Binding studies using singly phosphorylated peptides showed that individual motifs displayed weak affinities (> 100 μm) for Pin1-FL and each isolated domain. Analysis of dually phosphorylated peptides binding to Pin1-FL showed that inclusion of bivalent states was necessary to fit the data. The resulting complex model and fitted parameters were applied to predict the impact of bivalent states at low micromolar concentrations, demonstrating significant affinity enhancement for both dually phosphorylated peptides (3.5 and 24 μm for peptides based on the Ser131/Ser144 and Ser163/Ser173 regions, respectively). The complementary technique biolayer interferometry confirmed the predicted affinity enhancement for a representative set of singly and dually phosphorylated Ser131/Ser144 peptides at low micromolar concentrations, validating model predictions. These studies provide novel insights regarding the complexity of interactions between Pin1 and activated IRAK1, and more broadly suggest that phosphorylation of neighboring Ser/Thr-Pro motifs in proteins might provide competitive advantage at cellular concentrations for engaging with Pin1. © 2016 Federation of European

  4. Fasting mediated increase in p-BAD(ser155) and p-AKT(ser473) in the prefrontal cortex of mice.

    Science.gov (United States)

    Pitchaimani, Vigneshwaran; Arumugam, Somasundaram; Thandavarayan, Rajarajan Amirthalingam; Karuppagounder, Vengadeshprabhu; Sreedhar, Remya; Afrin, Rejina; Harima, Meilei; Suzuki, Hiroshi; Miyashita, Shizuka; Nomoto, Mayumi; Sone, Hirohito; Suzuki, Kenji; Watanabe, Kenichi

    2014-09-05

    BAD-deficient mice and fasting have several common functional roles in seizures, beta-hydroxybutyrate (BHB) uptake in brain and alteration in counterregulatory hormonal regulation during hypoglycemia. Neuronal specific insulin receptor knockout (NIRKO) mice display impaired counterregulatory hormonal responses during hypoglycemia. In this study we investigated the fasting mediated expression of p-BAD(ser155) and p-AKT(ser473) in different regions of brain (prefrontal cortex, hippocampus, midbrain and hypothalamus). Fasting specifically increases p-BAD(ser155) and p-AKT(ser473) in prefrontal cortex and decreases in other regions of brain. Our results suggest that fasting may increase the uptake BHB by decreasing p-BAD(ser155) in the brain during hypoglycemia except prefrontal cortex and it uncovers specific functional area of p-BAD(ser155) and p-AKT(ser473) that may regulates counter regulatory hormonal response. Overall in support with previous findings, fasting mediated hypoglycemia activates prefrontal cortex insulin signaling which influences the hypothalamic paraventricular nucleus mediated activation of sympathoadrenal hormonal responses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Neutron activation analysis of high purity substances

    International Nuclear Information System (INIS)

    Gil'bert, Eh.N.

    1987-01-01

    Peculiarities of neutron-activation analysis (NAA) of high purity substances are considered. Simultaneous determination of a wide series of elements, high sensitivity (the lower bound of determined contents 10 -9 -10 -10 %), high selectivity and accuracy (Sr=0.10-0.15, and may be decreased up to 0.001), possibility of analysis of the samples from several micrograms to hundreds of grams, simplicity of calibration may be thought NAA advantages. Questions of accounting of NAA systematic errors associated with the neutron flux screening by the analysed matrix and with production of radionuclides of determined elements from accompanying elements according to concurrent nuclear reactions, as well as accounting of errors due to self-absorption of recorded radiation by compact samples, are considered

  6. Detection of Pseudomonas aeruginosa Metabolite Pyocyanin in Water and Saliva by Employing the SERS Technique

    Directory of Open Access Journals (Sweden)

    Olga Žukovskaja

    2017-07-01

    Full Text Available Pyocyanin (PYO is a metabolite specific for Pseudomonas aeruginosa. In the case of immunocompromised patients, it is currently considered a biomarker for life-threating Pseudomonas infections. In the frame of this study it is shown, that PYO can be detected in aqueous solution by employing surface-enhanced Raman spectroscopy (SERS combined with a microfluidic platform. The achieved limit of detection is 0.5 μM. This is ~2 orders of magnitude below the concentration of PYO found in clinical samples. Furthermore, as proof of principle, the SERS detection of PYO in the saliva of three volunteers was also investigated. This body fluid can be collected in a non-invasive manner and is highly chemically complex, making the detection of the target molecule challenging. Nevertheless, PYO was successfully detected in two saliva samples down to 10 μM and in one sample at a concentration of 25 μM. This indicates that the molecules present in saliva do not inhibit the efficient adsorption of PYO on the surface of the employed SERS active substrates.

  7. High-surface-area active carbon

    International Nuclear Information System (INIS)

    O'Grady, T.M.; Wennerberg, A.N.

    1986-01-01

    This paper describes the preparation and properties of a unique active carbon having exceptionally high surface areas, over 2500 m 2 /gm, and extraordinary adsorptive capacities. The carbon is made by a direct chemical activation route in which petroleum coke or other carbonaceous sources are reacted with excess potassium hydroxide at 400 0 to 500 0 C to an intermediate product that is subsequently pyrolyzed at 800 0 to 900 0 C to active carbon containing potassium salts. These are removed by water washing and the carbon is dried to produce a powdered product. A granular carbon can also be made by further processing the powdered carbon by using specialized granulation techniques. Typical properties of the carbon include Iodine Numbers of 3000 to 3600, methylene blue adsorption of 650 to 750 mg/gm, pore volumes of 2.0 to 2.6 cc/gm and less than 3.0% ash. This carbon's high adsorption capacities make it uniquely suited for numerous demanding applications in the medical area, purifications, removal of toxic substances, as catalyst carriers, etc

  8. Acerca de tres dimensiones del ser humano

    OpenAIRE

    Fúnez, Rubén

    2007-01-01

    El autor resume las ideas importantes del libro "Tres dimensiones del ser humano", se pregunta por la importancia del planteamiento zubiriano, tanto para la historia de la filosofía, como para la situación que actualmente nos ha tocado vivir.

  9. Improved galvanic replacement growth of Ag microstructures on Cu micro-grid for enhanced SERS detection of organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Tian-Long [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan); Li, Ji-Guang, E-mail: LI.Jiguang@nims.go.jp [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan); Sun, Xudong, E-mail: xdsun@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Sakka, Yoshio [Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan)

    2016-04-01

    Galvanic growth of Ag nano/micro-structures on Cu micro-grid was systematically studied for surface-enhanced Raman scattering (SERS) applications. Detailed characterizations via FE-SEM and HR-TEM showed that processing parameters, (reaction time, Ag{sup +} concentration, and PVP addition) all substantially affect thermodynamics/kinetics of the replacement reaction to yield substrates of significantly different microstructures/homogeneities and thus varied SERS performances (sensitivity, enhancement factor, and reproducibility) of the Ag substrates in the detection of R6G analyte. PVP as an additive was shown to notably alter nucleation/growth behaviors of the Ag crystals and promote the deposition of dense and uniform Ag films of nearly monodisperse polyhedrons/nanoplates through suppressing dendrites crystallization. Under optimized synthesis (50 mM of Ag{sup +}, 30 s of reaction, and 700 wt.% of PVP), Ag substrates exhibiting a high Raman signal enhancement factor of ~ 1.1 × 10{sup 6} and a low relative standard deviation of ~ 0.13 in the repeated detection of 10 μM R6G were obtained. The facile deposition and excellent performance reported in this work may allow the Ag microstructures to find wider SERS applications. Moreover, growth mechanisms of the different Ag nano/micro-structures were discussed based on extensive FE-SEM and HR-TEM analysis. - Highlights: • A facile synthetic technique of growing SERS active Ag substrates onto Cu micro-grid has been systematically studied. • Changing processing parameters has yielded Ag crystals of various morphologies and SERS performances. • PVP additive was observed to suppress Ag dendrite crystallization for nearly monodispersed Ag polyhedrons/nanoplates. • PVP modified SERS substrate exhibits excellent EF and RSD values in the repeated detection of 10 μM R6G analyte.

  10. [TLC-SERS study on evodiamine in evodia rutaecarpa].

    Science.gov (United States)

    Zhang, Jin-zhi; Wang, Yuan; Chen, Hui; Shao, Hui-bo

    2007-05-01

    A new method for analyzing the ingredients of evodiamine (EV), rutaecarpine (RU), hydroxyevodiamine (HYD), evodiamide (ED), dihydrorutaecarpine (DRU) and 14-formyldihydrorutaecarpine (FDRU) in evodia rutaecarpa using high performance thin layer chromatography (TLC) and surface enhanced Raman spectroscopy (SERS) technique is reported. The character of this method is that standard samples are not needed. The results show that the characteristic spectral bands of EV, RU, HYD, and ED can be obtained from the TLC spot with microgramme of sample. The spectral band at 1562 cm(-1) was obtained with great enhancement. Molecule absorbed in surface silver sol by nr electrons in ring. The spectral bands of EV, RU, HYD and ED are obviously different due to their differences in structure. The TLC and SERS techniques standard samples are a convenient and speedy method to analyze chemical ingredients with high sensitivity for the study of the Chinese traditional medicine.

  11. High-active waste (HAW) data report

    International Nuclear Information System (INIS)

    Duijves, K.A.

    1991-06-01

    Data are presented from the High Active Waste (HAW) experiment, a large-scale, in situ test being performed underground at the Asse salt mine in Remlingen, FRG. These data include selected field information, the test configuration, instrumentation activities and comprehensive results from a large number of gauges. The results are measured data obtained from gap meters, thermocouples, linear displacement trans-ducers, extensometers, inclinometers and pressure gauges. Data certification practices have been described together with the quality assurance of the data reduction and of the data base management system. The experiment began on November 8, 1988 and will continue for five years. Data in this report cover the period from July 1st, 1990 to December 31, 1990. (author). 4 refs.; 100 figs.; 8 tabs

  12. Improving SERS uniformity by isolating hot spots in gold rod-in-shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shanshan; Liu, Zhonghui [Shanghai Jiao Tong University, School of Biomedical Engineering & Med-X Research Institute (China); Bartic, Carmen [KU Leuven, Department of Physics (Belgium); Xu, Hong, E-mail: xuhong@sjtu.edu.cn; Ye, Jian, E-mail: yejian78@sjtu.edu.cn [Shanghai Jiao Tong University, School of Biomedical Engineering & Med-X Research Institute (China)

    2016-08-15

    Surface-enhanced Raman scattering (SERS) tags show ultrasensitivity and multiplexing abilities due to strong and characteristic Raman signals and therefore can be utilized as optical labeling agents similar to fluorescent dyes and quantum dots for biosensing and bioimaging. However, SERS tags have the difficulty to realize quantitative analysis due to the uniformity and reproducibility issue. In this work, we have reported on a new type of SERS tag called Au rod-in-shell (RIS) gap-enhanced Raman tag (GERT). With the high-resolution transmission electron microscopy (TEM) and optical absorbance measurements, we have demonstrated the subnanometer sized gap junctions inside the RIS GERTs. SERS measurements and FDTD calculations show that the core–shell subnanometer gap geometry in the RIS GERTs not only generates strong SERS hot spots but also isolates SERS hot spots by Au shells to avoid the influence when the particle aggregates form, therefore showing better SERS uniformity and stronger SERS intensity than normal Au nanorods. Those RIS NPs exhibit great potential as the labeling agents for SERS-based bioimaging and biosensing applications.

  13. Improving SERS uniformity by isolating hot spots in gold rod-in-shell nanoparticles

    International Nuclear Information System (INIS)

    Wang, Shanshan; Liu, Zhonghui; Bartic, Carmen; Xu, Hong; Ye, Jian

    2016-01-01

    Surface-enhanced Raman scattering (SERS) tags show ultrasensitivity and multiplexing abilities due to strong and characteristic Raman signals and therefore can be utilized as optical labeling agents similar to fluorescent dyes and quantum dots for biosensing and bioimaging. However, SERS tags have the difficulty to realize quantitative analysis due to the uniformity and reproducibility issue. In this work, we have reported on a new type of SERS tag called Au rod-in-shell (RIS) gap-enhanced Raman tag (GERT). With the high-resolution transmission electron microscopy (TEM) and optical absorbance measurements, we have demonstrated the subnanometer sized gap junctions inside the RIS GERTs. SERS measurements and FDTD calculations show that the core–shell subnanometer gap geometry in the RIS GERTs not only generates strong SERS hot spots but also isolates SERS hot spots by Au shells to avoid the influence when the particle aggregates form, therefore showing better SERS uniformity and stronger SERS intensity than normal Au nanorods. Those RIS NPs exhibit great potential as the labeling agents for SERS-based bioimaging and biosensing applications.

  14. Underground disposal of high active waste

    International Nuclear Information System (INIS)

    Engelmann, H.J.

    1982-01-01

    This paper is concerned with the engineering aspects relating to the deep burial of high active waste in stable geological formations. The design of a repository depends upon a number of factors not least of which is the type of rock in which it is to be constructed. High level wastes must be isolated from man's environment for such periods that subsequent release will not result in an unacceptable hazard to human population. Design aspects of repositories are reviewed and conceptual design are present in relation to the geological formations under consideration. Over long time periods the most probable mode of release of radionuclides is through groundwater contacting the waste. The proposed concepts therefore include the use of engineered and natural barriers to delay the eventual release of waterborne radionuclides into mans environment. In all cases the ultimate barrier will be the geological formation. Nevertheless, depending upon the type of host rock, use will be made of various additional engineered barriers to delay water contacting the high level waste for several hundreds of years. During this time the level of radiation and associated heat emitted by the waste, will fall by several orders of magnitude and the rock temperatures within a repository will be returning to ambient. Thereafter the residual activity will mainly arise from the actinides. Containment may be enhanced by surrounding the canisters with materials having high sorption capabilities for many of the radionuclides involved. The depth at which a repository is excavated must be sufficient to ensure that the overburden will withstand changes in environmental conditions. The depth of cover required in different rock types may vary. In clay excavating at depth of up to -250 m appears feasible, while in hard rocks and salts working at depth of up to -1000 m is entirely practicable. (orig./RW)

  15. Processing ser and estar to locate objects and events

    Science.gov (United States)

    Dussias, Paola E.; Contemori, Carla; Román, Patricia

    2016-01-01

    In Spanish locative constructions, a different form of the copula is selected in relation to the semantic properties of the grammatical subject: sentences that locate objects require estar while those that locate events require ser (both translated in English as ‘to be’). In an ERP study, we examined whether second language (L2) speakers of Spanish are sensitive to the selectional restrictions that the different types of subjects impose on the choice of the two copulas. Twenty-four native speakers of Spanish and two groups of L2 Spanish speakers (24 beginners and 18 advanced speakers) were recruited to investigate the processing of ‘object/event + estar/ser’ permutations. Participants provided grammaticality judgments on correct (object + estar; event + ser) and incorrect (object + ser; event + estar) sentences while their brain activity was recorded. In line with previous studies (Leone-Fernández, Molinaro, Carreiras, & Barber, 2012; Sera, Gathje, & Pintado, 1999), the results of the grammaticality judgment for the native speakers showed that participants correctly accepted object + estar and event + ser constructions. In addition, while ‘object + ser’ constructions were considered grossly ungrammatical, ‘event + estar’ combinations were perceived as unacceptable to a lesser degree. For these same participants, ERP recording time-locked to the onset of the critical word ‘en’ showed a larger P600 for the ser predicates when the subject was an object than when it was an event (*La silla es en la cocina vs. La fiesta es en la cocina). This P600 effect is consistent with syntactic repair of the defining predicate when it does not fit with the adequate semantic properties of the subject. For estar predicates (La silla está en la cocina vs. *La fiesta está en la cocina), the findings showed a central-frontal negativity between 500–700 ms. Grammaticality judgment data for the L2 speakers of Spanish showed that beginners were significantly less

  16. [TLC-FT-SERS study on ingredients of Isrhynchophylline].

    Science.gov (United States)

    Wang, Yuan; Wang, Song-ying; Zhao, Yi-xue; Ren, Gui-fen; Zi, Feng-lan

    2002-02-01

    A new method for analysing the ingredients of Isrhynchophylline in Uncaria Rhynchophylla Jacks by thin layer chromatography (TLC) and the surface-enhanced Raman spectroscopy (SERS) is reported in this paper. The results show that the characteristic spectra bands of Isrhynchophylline situated at the thin layer with the amount of sample about 2.5 micrograms were obtained. The difference between SERS and solid spectra was found. Great enhancement of the 1,615 cm-1 spectral band was abstained. Molecule was absorbed in surface silver sol by pi electrons in phenyl and by pair of electrons in N together. An absorption model of Isrhynchophylline and silver sol was proposed. This method can be used to analyse the chemical ingredients with high sensitivity.

  17. Electrodeposited Silver Nanoparticles Patterned Hexagonally for SERS

    International Nuclear Information System (INIS)

    Gu, Geun Hoi; Lee, Sue Yeone; Suh, Jung Sang

    2010-01-01

    We have fabricated hexagonally patterned silver nanoparticles for surface-enhanced Raman scattering (SERS) by electrodepositing silver on the surface of an aluminum plate prepared by completely removing the oxide from anodic aluminum oxide (AAO) templates. Even after completely removing the oxide, well-ordered hexagonal patterns, similar to the shape of graphene, remained on the surface of the aluminum plate. The borders of the hexagonal pattern protruded up to form sorts of nano-mountains at both the sides and apexes of the hexagon, with the apexes protruding even more significantly than the sides. The aluminum plate prepared by completely removing the oxide has been used in the preparation of SERS substrates by sputter-coating of gold or silver on it. Instead of sputter-coating, here we have electro-deposited silver on the aluminum plate. When silver was electro-deposited on the plate, silver nanoparticles were made along the hexagonal margins.

  18. Flexible SERS Substrates: Challenges and Opportunities

    Science.gov (United States)

    2016-01-28

    are still widely used due to the ease with which silver and gold nanoparticles can be produced. Nanoparticle inks are colloidal suspensions of...interactions between the analyte, silver nanoparticles, and a salt. This system has also been applied to detection of trace antibiotics for food safety...Cleanable SERS Substrates Based on Silver Nanoparticle Decorated Electrospun Nano-fibrous Membranes Chaoyang Jiang Porous electrospun nanofibrous

  19. Criatividade em ação: ser criativo é ser criança

    Directory of Open Access Journals (Sweden)

    Antonio Mendes Silva Filho

    2012-11-01

    Full Text Available Todo ser humano é criativo e isso decorre da capacidade de imaginação. Essa capacidade é acentuada quando você tem a possibilidade de explorar e a curiosidade aguçada. Não exemplo melhor do que uma criança. Ser criativo é ser criança. Esta capacidade alcança o ápice quando se busca criar como criança fazendo uso de sagacidade, persistência, desorganização e com a possibilidade de errar. Isso é explorar e experimentar, deixando o cérebro livre e sem pressão, agindo despreocupadamente em determinado período de tempo. Nesse sentido, este artigo explora a importancia dar oportunidade do ser humano explorar sua capacidade de criar via imaginação

  20. Reusable nanosilver-coated magnetic particles for ultrasensitive SERS-based detection of malachite green in water samples

    Science.gov (United States)

    Song, Dan; Yang, Rong; Wang, Chongwen; Xiao, Rui; Long, Feng

    2016-01-01

    A novel nanosilver-deposited silica-coated Fe3O4 magnetic particle (Fe3O4@SiO2@Ag) with uniform size, good SERS activity and magnetic responsiveness was synthesized using amination polymer. The Fe3O4@SiO2@Ag magnetic particles have been successfully applied for ultrasensitive SERS detection of malachite green (MG) in water samples. The mechanism is that MG can be adsorbed on the silver surface of nanosilver-coated magnetic particles via one nitrogen atom, and the Raman signal intensity of MG is significantly enhanced by the nanosilver layer formed on the magnetic particles. The developed sensing system exhibited a sensitive response to MG in the range of 10 fM to 100 μM with a low limit of detection (LOD) 2 fM under optimal conditions. The LOD was several orders of magnitude lower than those of other methods. This SERS-based sensor showed good reproducibility and stability for MG detection. The silver-coated magnetic particles could easily be regenerated as SERS substrates only using low pH solution for multiple sensing events. The recovery of MG added to several water samples at different concentrations ranged from 90% to 110%. The proposed method facilitates the ultrasensitive analysis of dyes to satisfy the high demand for ensuring the safety of water sources. PMID:26964502

  1. Neutron activation analysis of high purity tellurium

    International Nuclear Information System (INIS)

    Gil'bert, Eh.N.; Verevkin, G.V.; Obrazovskij, E.G.; Shatskaya, S.S.

    1980-01-01

    A scheme of neutron activation analysis of high purity tellurium is developed. Weighed amount of Te (0.5 g) is irradiated for 20-40 hr in the flux of 2x10 13 neutron/(cm 2 xs). After decomposition of the sample impurities of gold and palladium are determined by the extraction with organic sulphides. Tellurium separation from the remaining impurities is carried out by the extraction with monothiobenzoic acid from weakly acidic HCl solutions in the presence of iodide-ions, suppressing silver extraction. Remaining impurity elements in the refined product are determined γ-spectrometrically. The method allows to determine 34 impurities with determination limits 10 -6 -10 -11 g

  2. FY16 ASME High Temperature Code Activities

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, M. J. [Chromtech Inc., Oak Ridge, TN (United States); Jetter, R. I. [R. I Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    One of the objectives of the ASME high temperature Code activities is to develop and validate both improvements and the basic features of Section III, Division 5, Subsection HB, Subpart B (HBB). The overall scope of this task is to develop a computer program to be used to assess whether or not a specific component under specified loading conditions will satisfy the elevated temperature design requirements for Class A components in Section III, Division 5, Subsection HB, Subpart B (HBB). There are many features and alternative paths of varying complexity in HBB. The initial focus of this task is a basic path through the various options for a single reference material, 316H stainless steel. However, the program will be structured for eventual incorporation all the features and permitted materials of HBB. Since this task has recently been initiated, this report focuses on the description of the initial path forward and an overall description of the approach to computer program development.

  3. Active interrogation of highly enriched uranium

    Science.gov (United States)

    Fairrow, Nannette Lea

    Safeguarding special nuclear material (SNM) in the Department of Energy Complex is vital to the national security of the United States. Active and passive nondestructive assays are used to confirm the presence of SNM in various configurations ranging from waste to nuclear weapons. Confirmation measurements for nuclear weapons are more challenging because the design complicates the detection of a distinct signal for highly enriched uranium. The emphasis of this dissertation was to investigate a new nondestructive assay technique that provides an independent and distinct signal to confirm the presence of highly enriched uranium (HEU). Once completed and tested this assay method could be applied to confirmation measurements of nuclear weapons. The new system uses a 14-MeV neutron source for interrogation and records the arrival time of neutrons between the pulses with a high efficiency detection system. The data is then analyzed by the Feynman reduced variance method. The analysis determined the amount of correlation in the data and provided a unique signature of correlated fission neutrons. Measurements of HEU spheres were conducted at Los Alamos with the new system. Then, Monte Carlo calculations were performed to verify hypothesis made about the behavior of the neutrons in the experiment. Comparisons of calculated counting rates by the Monte Carlo N-Particle Transport Code (MCNP) were made with the experimental data to confirm that the measured response reflected the desired behavior of neutron interactions in the highly enriched uranium. In addition, MCNP calculations of the delayed neutron build-up were compared with the measured data. Based on the results obtained from this dissertation, this measurement method has the potential to be expanded to include mass determinations of highly enriched uranium. Although many safeguards techniques exist for measuring special nuclear material, the number of assays that can be used to confirm HEU in shielded systems is

  4. The Gly482Ser genotype at the PPARGC1A gene and elevated blood pressure: a meta-analysis involving 13,949 individuals

    DEFF Research Database (Denmark)

    Vimaleswaran, Karani Santhanakrishnan; Luan, Jian'an; Andersen, Gitte

    2008-01-01

    The protein encoded by the PPARGC1A gene is expressed at high levels in metabolically active tissues and is involved in the control of oxidative stress via reactive oxygen species detoxification. Several recent reports suggest that the PPARGC1A Gly482Ser (rs8192678) missense polymorphism may relate...... inversely with blood pressure. We used conventional meta-analysis methods to assess the association between Gly482Ser and systolic (SBP) or diastolic blood pressures (DBP) or hypertension in 13,949 individuals from 17 studies, of which 6,042 were previously unpublished observations. The studies comprised...

  5. Fabrication of ITO-rGO/Ag NPs nanocomposite by two-step chronoamperometry electrodeposition and its characterization as SERS substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Analytical and Testing Center, Sichuan University of Science & Engineering, Zigong, Sichuan 643000 (China); Xu, Yi [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Wang, Chunyan [Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); School of Optoelectronic Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Zhao, Huazhou; Wang, Renjie; Liao, Xin [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Chen, Li; Chen, Gang [Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); School of Optoelectronic Engineering, Chongqing University, Shapingba, Chongqing 400044 (China)

    2015-09-15

    Highlights: • A novel structure of ITO-rGO/Ag NPs substrate was developed for SERS application. • Two-step chronoamperometry deposition method was used to prepare SERS substrate. • The SERS substrate had high SERS activity, good uniformity and reproducibility. - Abstract: A novel composite structure of reduced graphene oxide (rGO)–Ag nanoparticles (Ag NPs) nanocomposite, which was integrated on the indium tin oxide (ITO) glass by a facile and rapid two-step chronoamperometry electrodeposition route, was proposed and developed in this paper. SERS-activity of the rGO/Ag NPs nanocomposite was mainly affected by the structure and size of the fabricated rGO/Ag NPs nanocomposite. In the experiments, the operational conditions of electrodeposition process were studied in details. The electrodeposited time was the important controllable factor, which decided the particle size and surface coverage of the deposited Ag NPs on ITO glass. Under the optimized conditions, the detection limit for rhodamine6G (R6G) was as low as 10{sup −11} M and the Raman enhancement factor was as large as 5.9 × 10{sup 8}, which was 24 times higher than that for the ITO–Ag NPs substrate. Apart from this higher enhancement effect, it was also illustrated that extremely good uniformity and reproducibility with low standard deviation could be obtained by the prepared ITO-rGO/Ag NPs nanocomposite for SRES detection.

  6. Fabrication of ITO-rGO/Ag NPs nanocomposite by two-step chronoamperometry electrodeposition and its characterization as SERS substrate

    International Nuclear Information System (INIS)

    Wang, Rong; Xu, Yi; Wang, Chunyan; Zhao, Huazhou; Wang, Renjie; Liao, Xin; Chen, Li; Chen, Gang

    2015-01-01

    Highlights: • A novel structure of ITO-rGO/Ag NPs substrate was developed for SERS application. • Two-step chronoamperometry deposition method was used to prepare SERS substrate. • The SERS substrate had high SERS activity, good uniformity and reproducibility. - Abstract: A novel composite structure of reduced graphene oxide (rGO)–Ag nanoparticles (Ag NPs) nanocomposite, which was integrated on the indium tin oxide (ITO) glass by a facile and rapid two-step chronoamperometry electrodeposition route, was proposed and developed in this paper. SERS-activity of the rGO/Ag NPs nanocomposite was mainly affected by the structure and size of the fabricated rGO/Ag NPs nanocomposite. In the experiments, the operational conditions of electrodeposition process were studied in details. The electrodeposited time was the important controllable factor, which decided the particle size and surface coverage of the deposited Ag NPs on ITO glass. Under the optimized conditions, the detection limit for rhodamine6G (R6G) was as low as 10 −11 M and the Raman enhancement factor was as large as 5.9 × 10 8 , which was 24 times higher than that for the ITO–Ag NPs substrate. Apart from this higher enhancement effect, it was also illustrated that extremely good uniformity and reproducibility with low standard deviation could be obtained by the prepared ITO-rGO/Ag NPs nanocomposite for SRES detection

  7. Parameter optimization for Ag-coated TiO2 nanotube arrays as recyclable SERS substrates

    Science.gov (United States)

    Sun, Yuyang; Yang, Lulu; Liao, Fan; Dang, Qian; Shao, Mingwang

    2018-06-01

    The Ag-coated titanium dioxide nanotube arrays (Ag-coated TNTs) are obtained via the deposition of Ag nanoparticles on the two-step anodized TNTs. The wall thickness of TNTs is modulated via finite difference time domain simulation to get the favorable electromagnetic field for surface enhanced Raman scattering (SERS). Ag-coated TNTs with optimal wall thickness of 20 nm were employed as the SERS substrates to detect 2-mercaptobenzoxazole, which show superior detection sensitivity and uniformity. In addition, due to the photocatalysis of TNTs, the SERS substrates could clean themselves and be repeatedly used by photo-degradation of target molecules under the ultra-violet irradiation. The Ag-coated TNTs are a kind of bifunctional SERS substrates which can produce high-quality SERS signals and reuse to reduce the cost.

  8. El Segundo Cerebro del ser humano.

    OpenAIRE

    Rocío Ponce

    2015-01-01

    Existen dos tipos de cerebros, el conocido por todos formado por el sistema nervioso central, que sería el cerebro donde las emociones se forman en base a las experiencias anteriores. El segundo cerebro, el otro, ignorado por la mayoría de seres humanos es el cerebro que está en los intestinos, Sistema Nervioso Enteral o mesentérico, que se caracteriza por la relación del cerebro y aparato digestivo, este cerebro posee más neuronas que su par, guarda emociones, determina la respuesta de acuer...

  9. High-Throughput Analysis of Enzyme Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guoxin [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  10. On the chemical enhancement in SERS

    Science.gov (United States)

    Jensen, Lasse

    2012-12-01

    In Surface-enhanced Raman scattering (SERS), the Raman signal of a molecule adsorbed on a metal surface is enhanced by many orders of magnitude. This provides a "finger-print" of molecules which can be used in ultrasensitive sensing devises. Here we present a time-dependent density functional theory (TDDFT) study of the molecule-surface chemical coupling in SERS. A systematic study of the chemical enhancement (CHEM) of meta-and para-substituted pyridines interacting with a small silver cluster (Ag20) is presented. We find that the magnitude of chemical enhancement is governed to a large extent by the energy difference between the highest occupied energy level (HOMO) of the metal and the lowest unoccupied energy level (LUMO) of the molecule. A two-state approximation shows that the enhancement scales roughly as (ωX/ω¯e)4, where accent="true">ω¯e is an average excitation energy between the HOMO of the metal and the LUMO of the molecule and wX the HOMO-LUMO gap of the free molecule. Furthermore, we demonstrate that it is possible to control the CHEM enhancement by switching a dithienylethene photoswitch from its closed form to its open form. The open form of the photoswitch is found to be the strongest Raman scatterer when adsorbed on the surface whereas the opposite is found for the free molecule. This trend is explained using the simple two-state approximation.

  11. Non-labeling multiplex surface enhanced Raman scattering (SERS) detection of volatile organic compounds (VOCs)

    DEFF Research Database (Denmark)

    Wong, Chi Lok; Dinish, U. S.; Schmidt, Michael Stenbæk

    2014-01-01

    chemical sensing layer for the enrichment of gas molecules on sensor surface. The leaning nano-pillar substrate also showed highly reproducible SERS signal in cyclic VOCs detection, which can reduce the detection cost in practical applications. Further, multiplex SERS detection on different combination...... device for multiplex, specific and highly sensitive detection of complex VOCs samples that can find potential applications in exhaled breath analysis, hazardous gas analysis, homeland security and environmental monitoring....

  12. P-Ser-HPr-a link between carbon metabolism and the virulence of some pathogenic bacteria

    DEFF Research Database (Denmark)

    Mijakovic, Ivan

    2005-01-01

    HPr kinase/phosphorylase phosphorylates HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system, at serine-46. P-Ser-HPr is the central regulator of carbon metabolism in Gram-positive bacteria, but also plays a role in virulence development of certain...... pathogens. In Listeria monocytogenes, several virulence genes, which depend on the transcription activator PrfA, are repressed by glucose, fructose, etc., in a catabolite repressor (CcpA)-independent mechanism. However, the catabolite co-repressor P-Ser-HPr was found to inhibit the activity of Prf...... is preceded by an operator site, which serves as target for the CcpA/P-Ser-HPr complex. Numerous Gram-negative pathogens also contain hprK, which is often organised in an operon with transcription regulators necessary for the development of virulence, indicating that in these organisms P-Ser-HPr also plays...

  13. Nanosphere Lithography on Fiber: Towards Engineered Lab-On-Fiber SERS Optrodes

    Directory of Open Access Journals (Sweden)

    Giuseppe Quero

    2018-02-01

    Full Text Available In this paper we report on the engineering of repeatable surface enhanced Raman scattering (SERS optical fiber sensor devices (optrodes, as realized through nanosphere lithography. The Lab-on-Fiber SERS optrode consists of polystyrene nanospheres in a close-packed arrays configuration covered by a thin film of gold on the optical fiber tip. The SERS surfaces were fabricated by using a nanosphere lithography approach that is already demonstrated as able to produce highly repeatable patterns on the fiber tip. In order to engineer and optimize the SERS probes, we first evaluated and compared the SERS performances in terms of Enhancement Factor (EF pertaining to different patterns with different nanosphere diameters and gold thicknesses. To this aim, the EF of SERS surfaces with a pitch of 500, 750 and 1000 nm, and gold films of 20, 30 and 40 nm have been retrieved, adopting the SERS signal of a monolayer of biphenyl-4-thiol (BPT as a reliable benchmark. The analysis allowed us to identify of the most promising SERS platform: for the samples with nanospheres diameter of 500 nm and gold thickness of 30 nm, we measured values of EF of 4 × 105, which is comparable with state-of-the-art SERS EF achievable with highly performing colloidal gold nanoparticles. The reproducibility of the SERS enhancement was thoroughly evaluated. In particular, the SERS intensity revealed intra-sample (i.e., between different spatial regions of a selected substrate and inter-sample (i.e., between regions of different substrates repeatability, with a relative standard deviation lower than 9 and 15%, respectively. Finally, in order to determine the most suitable optical fiber probe, in terms of excitation/collection efficiency and Raman background, we selected several commercially available optical fibers and tested them with a BPT solution used as benchmark. A fiber probe with a pure silica core of 200 µm diameter and high numerical aperture (i.e., 0.5 was found to be the

  14. Hierarchical Ag mesostructures for single particle SERS substrate

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Minwei, E-mail: xuminwei@xjtu.edu.cn; Zhang, Yin

    2017-01-30

    Highlights: • Hierarchical Ag mesostructures with the size of 250, 360 and 500 nm are synthesized via a seed-mediated approach. • The Ag mesostructures present the tailorable size and highly roughened surfaces. • The average enhancement factors for individual Ag mesostructures were estimated to be as high as 10{sup 6}. - Abstract: Hierarchical Ag mesostructures with highly rough surface morphology have been synthesized at room temperature through a simple seed-mediated approach. Electron microscopy characterizations indicate that the obtained Ag mesostructures exhibit a textured surface morphology with the flower-like architecture. Moreover, the particle size can be tailored easily in the range of 250–500 nm. For the growth process of the hierarchical Ag mesostructures, it is believed that the self-assembly mechanism is more reasonable rather than the epitaxial overgrowth of Ag seed. The oriented attachment of nanoparticles is revealed during the formation of Ag mesostructures. Single particle surface enhanced Raman spectra (sp-SERS) of crystal violet adsorbed on the hierarchical Ag mesostructures were measured. Results reveal that the hierarchical Ag mesostructures can be highly sensitive sp-SERS substrates with good reproducibility. The average enhancement factors for individual Ag mesostructures are estimated to be about 10{sup 6}.

  15. High Flight. Aerospace Activities, K-12.

    Science.gov (United States)

    Oklahoma State Dept. of Education, Oklahoma City.

    Following discussions of Oklahoma aerospace history and the history of flight, interdisciplinary aerospace activities are presented. Each activity includes title, concept fostered, purpose, list of materials needed, and procedure(s). Topics include planets, the solar system, rockets, airplanes, air travel, space exploration, principles of flight,…

  16. PKCδ-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

    International Nuclear Information System (INIS)

    Greene, Michael W.; Ruhoff, Mary S.; Roth, Richard A.; Kim, Jeong-a; Quon, Michael J.; Krause, Jean A.

    2006-01-01

    The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKCδ on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKCδ-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKCδ catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1

  17. Design of SERS nanoprobes for Raman imaging: materials, critical factors and architectures.

    Science.gov (United States)

    Li, Mingwang; Qiu, Yuanyuan; Fan, Chenchen; Cui, Kai; Zhang, Yongming; Xiao, Zeyu

    2018-05-01

    Raman imaging yields high specificity and sensitivity when compared to other imaging modalities, mainly due to its fingerprint signature. However, intrinsic Raman signals are weak, thus limiting medical applications of Raman imaging. By adsorbing Raman molecules onto specific nanostructures such as noble metals, Raman signals can be significantly enhanced, termed surface-enhanced Raman scattering (SERS). Recent years have witnessed great interest in the development of SERS nanoprobes for Raman imaging. Rationally designed SERS nanoprobes have greatly enhanced Raman signals by several orders of magnitude, thus showing great potential for biomedical applications. In this review we elaborate on recent progress in design strategies with emphasis on material properties, modifying factors, and structural parameters.

  18. Synthesis of silver nanocubes as a SERS substrate for the determination of pesticide paraoxon and thiram

    Science.gov (United States)

    Wang, Bin; Zhang, Li; Zhou, Xia

    2014-03-01

    The silver cube-like nanostructure with uniform size and high yield have been synthesized through the rapid sulfide-mediated polyol method. The morphology, structure and optical properties of the as-prepared silver nanocubes were characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The Surface-Enhanced Raman Scattering (SERS) performance of the as-prepared Ag nanocubes was characterized by crystal violet (CV) as the probe molecules. Furthermore, the low levels of thiram and pesticide paraoxon can be detected by the SERS technique, which shows that the silver nanocubes as a SERS substrate have excellent sensitivity and reproducibility.

  19. Chitinolytic activity of highly halotolerant Streptomyces tendae ...

    African Journals Online (AJOL)

    User

    many plant diseases by degrading the chitin polymer in ... Chitin in soil can be degraded by a wide variety of microorganisms including fungal and bacterial species. .... fraction contained chitinolytic activity was dialyzed using plastic.

  20. Ser lo mismo, ser diferente: contra la masificación

    OpenAIRE

    Saldarriaga Roa, Alberto

    2005-01-01

    La sociedad moderna se ha configurado, en los dos últimos siglos, como una sociedad de masas. Esto parece ser una condición sine qua non de su estructura y operatividad. La masificación se manifiesta no sólo en el comportamiento social sino también en el

  1. Phospho-Bcl-xL(Ser62) influences spindle assembly and chromosome segregation during mitosis.

    Science.gov (United States)

    Wang, Jianfang; Beauchemin, Myriam; Bertrand, Richard

    2014-01-01

    Functional analysis of a series of phosphorylation mutants reveals that Bcl-xL(Ser62Ala) influences cell entry into anaphase and mitotic exit in taxol-exposed cells compared with cells expressing wild-type Bcl-xL or a series of other phosphorylation mutants, an effect that appears to be independent of its anti-apoptotic activity. During normal mitosis progression, Bcl-xL(Ser62) is strongly phosphorylated by PLK1 and MAPK14/SAPKp38α at the prometaphase, metaphase, and the anaphase boundaries, while it is de-phosphorylated at telophase and cytokinesis. Phospho-Bcl-xL(Ser62) localizes in centrosomes with γ-tubulin and in the mitotic cytosol with some spindle-assembly checkpoint signaling components, including PLK1, BubR1, and Mad2. In taxol- and nocodazole-exposed cells, phospho-Bcl-xL(Ser62) also binds to Cdc20- Mad2-, BubR1-, and Bub3-bound complexes, while Bcl-xL(Ser62Ala) does not. Silencing Bcl-xL expression and expressing the phosphorylation mutant Bcl-xL(Ser62Ala) lead to an increased number of cells harboring mitotic spindle defects including multipolar spindle, chromosome lagging and bridging, aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h. Together, the data indicate that during mitosis, Bcl-xL(Ser62) phosphorylation impacts on spindle assembly and chromosome segregation, influencing chromosome stability. Observations of mitotic cells harboring aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h were also made with cells expressing the phosphorylation mutant Bcl-xL(Ser49Ala) and dual mutant Bcl-xL(Ser49/62Ala).

  2. Stabilization of alanine substituted p53 protein at Ser15, Thr18, and Ser20 in response to ionizing radiation

    International Nuclear Information System (INIS)

    Yamauchi, Motohiro; Suzuki, Keiji; Kodama, Seiji; Watanabe, Masami

    2004-01-01

    Phosphorylation of p53 at Ser15, Thr18, and Ser20 has been thought to be important for p53 stabilization in response to ionizing radiation. In the present study, we examined the X-ray-induced stabilization of Ala-substituted p53 protein at Ser15, Thr18, and Ser20, whose gene expression was controlled under an ecdyson-inducible promoter. We found that all single-, double-, or triple-Ala-substituted p53 at Ser15, Yhr18, and Ser20 were accumulated in the nucleus similarly to wild-type p53 after X-irradiation. These results indicate that the phosphorylation of p53 at Ser15, Thr18, and Ser20 is not necessarily needed for p53 stabilization in response to ionizing radiation

  3. [Study on the ingredients of reserpine by TLC-FT-SERS].

    Science.gov (United States)

    Wang, Y; Zi, F; Wang, Y; Zhao, Y; Zhang, X; Weng, S

    1999-12-01

    A new method for analysing the ingredients of reserpine by thin layer chromatography (TLC) and surface-enhanced Raman spectroscopy (SERS) is reported in this paper. The results show that the characteristic spectral bands of reserpine satuated at the thin layer with the amount of sample about 2 microg were obtained. The difference between SERS and solid spectra was found. An absorption model of reserpine and silver sol was proposed. This method can be used to analyse the chemical ingredients with high sensitivity.

  4. O Talco deve ser utilizado para Pleurodese

    Directory of Open Access Journals (Sweden)

    Steven A. Sahn

    2001-03-01

    Full Text Available RESUMO: A pleurodese està recomendada nos den·ames pleurais malignos quando o tumor não é sensível à quimioterapia. Aprcsenta taxas de sucesso vari:lveis em parte justificadas pelos diferentes agentes e doses utilizadas, a selecção de doentes eo tipo de técnica aplicada. O talco parece ser o agente mais efi caz de pleurodese.Steven Sahn defende que o talco deve ser utilizado para pleurodese, apoiando a sua opini ao em diferentes factores:Mecanisme da pleurodese para talcagcm - o talco após contacto com as células mesoteliais promove um influxo de neutrófil os IL8 mediadus e posterior acumulação de macrófagos, diminuiçãa actividade fibrinolftica e aumento do factor de crescimento dos fi broblastos. Quando o tumor reveste uma grande area de mesotclio, a pleurodese não é tao eficaz.Eficácia - uma revisão da li teratura inglesa de I966 a 1994 constatou que u talco foi o agente mais eficaz de pleurodese, cum uma taxa de sucesso de 93%, comparada cum a da tetraciclina de 67 %, doxicicli na de 72% e bleomicina de 54%. Outras séries reve1aram uma taxa de sucesso do talco sempre superior a 91 %.Custo - o talco é pouco dispendioso e se apl icado em suspensao (“slutTy” por tubo de toracostomia ainda reduz mais os custos inerentes a uma toracoscopia 4uando se utiliza o talco em pó, aprescntando cstas duas tecnicas, taxas ue eticacia scmelhantes. Reacçãoes Adversas Minor e Major Agudas- a toracalgia e a febre são OS efcitos adversos mains frequcntes, frequcntes de todos os agentes de pleurudese. A toracalgia surge em 7% dos doentcs submetiuos a plcurodesc com talco, em 28% com a bleomicina c 40% com a dox iciclina. A tetraciclina provoca geralmente wracalgia grave. A febre surge entre I6 a 69% após talcagem não ultrapassando as 72 horas.As reacçãoes adversas graves sao raras e incluern o cmpiema. arritmia cardfaca e insufcicncia rcspiratória. Se o talco

  5. Highly active thermally stable nanoporous gold catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Biener, Juergen; Wittstock, Arne; Biener, Monika M.; Bagge-Hansen, Michael; Baeumer, Marcus; Wichmann, Andre; Neuman, Bjoern

    2016-12-20

    In one embodiment, a system includes a nanoporous gold structure and a plurality of oxide particles deposited on the nanoporous gold structure; the oxide particles are characterized by a crystalline phase. In another embodiment, a method includes depositing oxide nanoparticles on a nanoporous gold support to form an active structure and functionalizing the deposited oxide nanoparticles.

  6. Fabrication of Semiconductor ZnO Nanostructures for Versatile SERS Application

    Directory of Open Access Journals (Sweden)

    Lili Yang

    2017-11-01

    Full Text Available Since the initial discovery of surface-enhanced Raman scattering (SERS in the 1970s, it has exhibited a huge potential application in many fields due to its outstanding advantages. Since the ultra-sensitive noble metallic nanostructures have increasingly exposed themselves as having some problems during application, semiconductors have been gradually exploited as one of the critical SERS substrate materials due to their distinctive advantages when compared with noble metals. ZnO is one of the most representative metallic oxide semiconductors with an abundant reserve, various and cost-effective fabrication techniques, as well as special physical and chemical properties. Thanks to the varied morphologies, size-dependent exciton, good chemical stability, a tunable band gap, carrier concentration, and stoichiometry, ZnO nanostructures have the potential to be exploited as SERS substrates. Moreover, other distinctive properties possessed by ZnO such as biocompatibility, photocatcalysis and self-cleaning, and gas- and chemo-sensitivity can be synergistically integrated and exerted with SERS activity to realize the multifunctional potential of ZnO substrates. In this review, we discuss the inevitable development trend of exploiting the potential semiconductor ZnO as a SERS substrate. After clarifying the root cause of the great disparity between the enhancement factor (EF of noble metals and that of ZnO nanostructures, two specific methods are put forward to improve the SERS activity of ZnO, namely: elemental doping and combination of ZnO with noble metals. Then, we introduce a distinctive advantage of ZnO as SERS substrate and illustrate the necessity of reporting a meaningful average EF. We also summarize some fabrication methods for ZnO nanostructures with varied dimensions (0–3 dimensions. Finally, we present an overview of ZnO nanostructures for the versatile SERS application.

  7. Conversion of highly active waste to solids

    International Nuclear Information System (INIS)

    Scheffler, K.

    Borosilicate glasses were selected as matrix material for solidification of highly radioactive wastes. Current laboratory work on the VERA process is described. Goals were met by a five-component glass VG-38 and a glass-ceramic VC-15. The VERA process is described: flowsheet, denitration, calcinator, fusion facility

  8. Activities in nuclear and high energy physics

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    High energy and nuclear physics research concerning bubble chamber investigations, European hybrid system ACCMOR, WA 18, PETRA, PEP, VA 4, SING, LENA, LEP 3 and DELPHI experiments is summarized. Experiments with electron beams, and in pions and muons physics, and radiochemistry are reported on.

  9. MODOS DE SER DA JUVENTUDE OCIDENTAL

    Directory of Open Access Journals (Sweden)

    Prof. Dr. Luiz Antônio Dias

    2015-09-01

    Full Text Available O presente artigo é resultado de investigações ainda em andamento no Grupo de Pesquisa “Culturas juvenis, consumo e mobilidade urbana na contemporaneidade”, iniciadas em 2013 junto ao Programa de Mestrado Interdisciplinar em Ciências Humanas da Universidade de Santo Amaro (UNISA. A pesquisa dedica-se a entender, entre outras reflexões, o percurso dos jovens na sociedade contemporânea e as contribuições que eles trouxeram para repensar o espaço urbano. Nesse estudo buscamos localizar no espaço e no tempo em quais condições históricas o sentimento de juventude apareceu para a sociedade. Em seguida, fazemos um minucioso levantamento da trajetória dessa nova categoria social nos mais diferentes períodos da história contemporânea. Chegamos, assim, ao século XX, momento em que as reuniões juvenis deixam de ser fatos isolados e adquirem conotações de manifestações verdadeiramente sociais. Ainda nessa perspectiva de análise, buscamos compreender as similitudes, aproximações e distanciamentos do movimento punk com seus congêneres do passado.

  10. Llegar a ser Simone de Beauvoir

    Directory of Open Access Journals (Sweden)

    Nora Levinton Dolman

    2009-01-01

    Full Text Available A la manera de un Psicoanálisis aplicado a la obra de Simone de Beauvoir se señalan algunos aspectos cruciales que reflejan cómo se va configurando la vida y el pensamiento de una mujer que encarnó, para muchas de nosotras, un modelo de identificación. Su trabajo es en este sentido un espejo y una valiosa muestra de la naturaleza proyectiva de muchos de sus enunciados, donde a partir de su irreemplazable experiencia Simone arriba a conclusiones en las que podemos seguir el rastro de sus vivencias personales. En el contexto singular de su historia personal y en cómo es relatada. Al exponer su vida en sus libros y en numerosas entrevistas concedidas a distintos medios, ha dado lugar a que surgieran diferentes interpretaciones, por lo tanto a que sus palabras y argumentos puedan, como en este artículo, ser utilizados, contrastados entre sí y sometidos a exploración.

  11. Libertas que serás enfermagem

    Directory of Open Access Journals (Sweden)

    Mary Anne Fontenele Martins

    1998-09-01

    Full Text Available O título deste ensaio nos faz lembrar a Inconfidência Mineira, que teve como líder José Joaquim da Silva Xavier, o Tiradentes, sendo um movimento que ansiava por liberdade, assim como a enfermagem que, ao longo dos anos, vem construindo sua história e caminhando em busca de sua autonomia. A presente pesquisa tem como objetivo investigar os caminhos percorridos pela enfermagem, enquanto ciência na busca de sua autonomia, e refletir sobre a atuação do enfermeiro enquanto profissional criativo e autônomo. Estudo respaldado no materialismo histórico e dialético, realizado no período de maio a agosto de 1997 com enfermeiras do Estado do Ceará, que estão envolvidas com o processo histórico da profissão. Os resultados deram origem a uma categoria central, prática profissional e outras três: autonomia, criatividade e disposição para enfrentar desafios, que favoreceram uma melhor compreensão dos caminhos já trilhados pela enfermagem, além de nos permitir entender que o enfermeiro pode ser autônomo e livre.

  12. SERS imaging of cell-surface biomolecules metabolically labeled with bioorthogonal Raman reporters.

    Science.gov (United States)

    Xiao, Ming; Lin, Liang; Li, Zefan; Liu, Jie; Hong, Senlian; Li, Yaya; Zheng, Meiling; Duan, Xuanming; Chen, Xing

    2014-08-01

    Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbondeuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Surface enhanced Raman spectroscopy (SERS) for in vitro diagnostic testing at the point of care

    Science.gov (United States)

    Marks, Haley; Schechinger, Monika; Garza, Javier; Locke, Andrea; Coté, Gerard

    2017-06-01

    Point-of-care (POC) device development is a growing field that aims to develop low-cost, rapid, sensitive in-vitro diagnostic testing platforms that are portable, self-contained, and can be used anywhere - from modern clinics to remote and low resource areas. In this review, surface enhanced Raman spectroscopy (SERS) is discussed as a solution to facilitating the translation of bioanalytical sensing to the POC. The potential for SERS to meet the widely accepted "ASSURED" (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable) criterion provided by the World Health Organization is discussed based on recent advances in SERS in vitro assay development. As SERS provides attractive characteristics for multiplexed sensing at low concentration limits with a high degree of specificity, it holds great promise for enhancing current efforts in rapid diagnostic testing. In outlining the progression of SERS techniques over the past years combined with recent developments in smart nanomaterials, high-throughput microfluidics, and low-cost paper diagnostics, an extensive number of new possibilities show potential for translating SERS biosensors to the POC.

  14. Surface enhanced Raman spectroscopy (SERS for in vitro diagnostic testing at the point of care

    Directory of Open Access Journals (Sweden)

    Marks Haley

    2017-06-01

    Full Text Available Point-of-care (POC device development is a growing field that aims to develop low-cost, rapid, sensitive in-vitro diagnostic testing platforms that are portable, self-contained, and can be used anywhere – from modern clinics to remote and low resource areas. In this review, surface enhanced Raman spectroscopy (SERS is discussed as a solution to facilitating the translation of bioanalytical sensing to the POC. The potential for SERS to meet the widely accepted “ASSURED” (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable criterion provided by the World Health Organization is discussed based on recent advances in SERS in vitro assay development. As SERS provides attractive characteristics for multiplexed sensing at low concentration limits with a high degree of specificity, it holds great promise for enhancing current efforts in rapid diagnostic testing. In outlining the progression of SERS techniques over the past years combined with recent developments in smart nanomaterials, high-throughput microfluidics, and low-cost paper diagnostics, an extensive number of new possibilities show potential for translating SERS biosensors to the POC.

  15. CisSERS: Customizable In Silico Sequence Evaluation for Restriction Sites.

    Directory of Open Access Journals (Sweden)

    Richard M Sharpe

    Full Text Available High-throughput sequencing continues to produce an immense volume of information that is processed and assembled into mature sequence data. Data analysis tools are urgently needed that leverage the embedded DNA sequence polymorphisms and consequent changes to restriction sites or sequence motifs in a high-throughput manner to enable biological experimentation. CisSERS was developed as a standalone open source tool to analyze sequence datasets and provide biologists with individual or comparative genome organization information in terms of presence and frequency of patterns or motifs such as restriction enzymes. Predicted agarose gel visualization of the custom analyses results was also integrated to enhance the usefulness of the software. CisSERS offers several novel functionalities, such as handling of large and multiple datasets in parallel, multiple restriction enzyme site detection and custom motif detection features, which are seamlessly integrated with real time agarose gel visualization. Using a simple fasta-formatted file as input, CisSERS utilizes the REBASE enzyme database. Results from CisSERS enable the user to make decisions for designing genotyping by sequencing experiments, reduced representation sequencing, 3'UTR sequencing, and cleaved amplified polymorphic sequence (CAPS molecular markers for large sample sets. CisSERS is a java based graphical user interface built around a perl backbone. Several of the applications of CisSERS including CAPS molecular marker development were successfully validated using wet-lab experimentation. Here, we present the tool CisSERS and results from in-silico and corresponding wet-lab analyses demonstrating that CisSERS is a technology platform solution that facilitates efficient data utilization in genomics and genetics studies.

  16. CisSERS: Customizable In Silico Sequence Evaluation for Restriction Sites.

    Science.gov (United States)

    Sharpe, Richard M; Koepke, Tyson; Harper, Artemus; Grimes, John; Galli, Marco; Satoh-Cruz, Mio; Kalyanaraman, Ananth; Evans, Katherine; Kramer, David; Dhingra, Amit

    2016-01-01

    High-throughput sequencing continues to produce an immense volume of information that is processed and assembled into mature sequence data. Data analysis tools are urgently needed that leverage the embedded DNA sequence polymorphisms and consequent changes to restriction sites or sequence motifs in a high-throughput manner to enable biological experimentation. CisSERS was developed as a standalone open source tool to analyze sequence datasets and provide biologists with individual or comparative genome organization information in terms of presence and frequency of patterns or motifs such as restriction enzymes. Predicted agarose gel visualization of the custom analyses results was also integrated to enhance the usefulness of the software. CisSERS offers several novel functionalities, such as handling of large and multiple datasets in parallel, multiple restriction enzyme site detection and custom motif detection features, which are seamlessly integrated with real time agarose gel visualization. Using a simple fasta-formatted file as input, CisSERS utilizes the REBASE enzyme database. Results from CisSERS enable the user to make decisions for designing genotyping by sequencing experiments, reduced representation sequencing, 3'UTR sequencing, and cleaved amplified polymorphic sequence (CAPS) molecular markers for large sample sets. CisSERS is a java based graphical user interface built around a perl backbone. Several of the applications of CisSERS including CAPS molecular marker development were successfully validated using wet-lab experimentation. Here, we present the tool CisSERS and results from in-silico and corresponding wet-lab analyses demonstrating that CisSERS is a technology platform solution that facilitates efficient data utilization in genomics and genetics studies.

  17. Reassessing SERS enhancement factors: using thermodynamics to drive substrate design.

    Science.gov (United States)

    Guicheteau, J A; Tripathi, A; Emmons, E D; Christesen, S D; Fountain, Augustus W

    2017-12-04

    Over the past 40 years fundamental and application research into Surface-Enhanced Raman Scattering (SERS) has been explored by academia, industry, and government laboratories. To date however, SERS has achieved little commercial success as an analytical technique. Researchers are tackling a variety of paths to help break through the commercial barrier by addressing the reproducibility in both the SERS substrates and SERS signals as well as continuing to explore the underlying mechanisms. To this end, investigators use a variety of methodologies, typically studying strongly binding analytes such as aromatic thiols and azarenes, and report SERS enhancement factor calculations. However a drawback of the traditional SERS enhancement factor calculation is that it does not yield enough information to understand substrate reproducibility, application potential with another analyte, or the driving factors behind the molecule-metal interaction. Our work at the US Army Edgewood Chemical Biological Center has focused on these questions and we have shown that thermodynamic principles play a key role in the SERS response and are an essential factor in future designs of substrates and applications. This work will discuss the advantages and disadvantages of various experimental techniques used to report SERS enhancement with planar SERS substrates and present our alternative SERS enhancement value. We will report on three types of analysis scenarios that all yield different information concerning the effectiveness of the SERS substrate, practical application of the substrate, and finally the thermodynamic properties of the substrate. We believe that through this work a greater understanding for designing substrates will be achieved, one that is based on both thermodynamic and plasmonic properties as opposed to just plasmonic properties. This new understanding and potential change in substrate design will enable more applications for SERS based methodologies including targeting

  18. Modification of the SERS spectrum of cyanide traces due to complex formation between cyanide and silver

    Science.gov (United States)

    Cao Dao, Tran; Kieu, Ngoc Minh; Quynh Ngan Luong, Truc; Cao, Tuan Anh; Hai Nguyen, Ngoc; Le, Van Vu

    2018-06-01

    It is well known that cyanide is an extremely toxic lethal poison with human death within minutes after exposure to only 300 ppm cyanide. On the other hand, cyanide is released into the environment (mainly through waste water) every day from various human activities. Therefore, rapid, sensitive and cost-effective cyanide trace detection is an urgent need. Surface-enhanced Raman scattering (SERS) is a method that meets these requirements. It should be noted, however, that in this technique SERS substrates, which are usually made of gold or silver, will be leached with aqueous cyanide by the formation of complexes between gold or silver with cyanide. This will cause the SERS spectrum of cyanide to be modified. When determining cyanide concentrations by SERS analysis, this spectral modification should be taken into account. This report presents the SERS spectral modification of aqueous cyanide traces (in ppm and lower concentration range) when the SERS substrates used are flower-like silver micro-structures.

  19. Biofabrication of chitosan-silver composite SERS substrates enabling quantification of adenine by a spectroscopic shift

    International Nuclear Information System (INIS)

    Luo, X L; Bentley, W E; Buckhout-White, S; Rubloff, G W

    2011-01-01

    Surface-enhanced Raman scattering (SERS) has grown dramatically as an analytical tool for the sensitive and selective detection of molecules adsorbed on nano-roughened noble metal structures. Quantification with SERS based on signal intensity remains challenging due to the complicated fabrication process to obtain well-dispersed nanoparticles and well-ordered substrates. We report a new biofabrication strategy of SERS substrates that enable quantification through a newly discovered spectroscopic shift resulting from the chitosan-analyte interactions in solution. We demonstrate this phenomenon by the quantification of adenine, which is an essential part of the nucleic acid structure and a key component in pathways which generate signal molecules for bacterial communications. The SERS substrates were fabricated simply by sequential electrodeposition of chitosan on patterned gold electrodes and electroplating of a silver nitrate solution through the chitosan scaffold to form a chitosan-silver nanoparticle composite. Active SERS signals of adenine solutions were obtained in real time from the chitosan-silver composite substrates with a significant concentration-dependent spectroscopic shift. The Lorentzian curve fitting of the dominant peaks suggests the presence of two separate peaks with a concentration-dependent area percentage of the separated peaks. The chitosan-mediated composite SERS substrates can be easily biofabricated on predefined electrodes within microfluidic channels for real-time detection in microsystems.

  20. Highly Stable and Active Catalyst for Sabatier Reactions

    Science.gov (United States)

    Hu, Jianli; Brooks, Kriston P.

    2012-01-01

    Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

  1. Improving SERS Detection of Bacillus thuringiensis Using Silver Nanoparticles Reduced with Hydroxylamine and with Citrate Capped Borohydride

    International Nuclear Information System (INIS)

    Felix-Rivera, H.; Gonzalez, R.; Rodriguez, G.D.M.; Oliva, M. P.; Hernandez-Rivera, S.P.; Rios-Velazquez, C.

    2011-01-01

    The development of techniques that could be useful in fields other than biological warfare agents countermeasures such as medical diagnostics, industrial microbiology, and environmental applications have become a very important subject of research. Raman spectroscopy can be used in near field or at long distances from the sample to obtain fingerprinting information of chemical composition of microorganisms. In this research, biochemical components of the cell wall and endospores of Bacillus thuringiensis (Bt) were identified by surface-enhanced Raman scattering (SERS) spectroscopy using silver (Ag) nanoparticles (NPs) reduced by hydroxylamine and borohydride capped with sodium citrate. Activation of hot spots, aggregation and surface charge modification of the NPs, was studied and optimized to obtain signal enhancements from Bt by SERS. Slight aggregation of the NPs as well as surface charge modification to a more acidic ambient was induced using small-size borohydride-reduced NPs in the form of metallic suspensions aimed at increasing the Ag NP-Bt interactions. Hydroxylamine-reduced NPs required slight aggregation and no pH modifications in order to obtain high spectral quality results in bringing out SERS signatures of Bt.

  2. Improving SERS Detection of Bacillus thuringiensis Using Silver Nanoparticles Reduced with Hydroxylamine and with Citrate Capped Borohydride

    Directory of Open Access Journals (Sweden)

    Hilsamar Félix-Rivera

    2011-01-01

    Full Text Available The development of techniques that could be useful in fields other than biological warfare agents countermeasures such as medical diagnostics, industrial microbiology, and environmental applications have become a very important subject of research. Raman spectroscopy can be used in near field or at long distances from the sample to obtain fingerprinting information of chemical composition of microorganisms. In this research, biochemical components of the cell wall and endospores of Bacillus thuringiensis (Bt were identified by surface-enhanced Raman scattering (SERS spectroscopy using silver (Ag nanoparticles (NPs reduced by hydroxylamine and borohydride capped with sodium citrate. Activation of “hot spots”, aggregation and surface charge modification of the NPs, was studied and optimized to obtain signal enhancements from Bt by SERS. Slight aggregation of the NPs as well as surface charge modification to a more acidic ambient was induced using small-size borohydride-reduced NPs in the form of metallic suspensions aimed at increasing the Ag NP-Bt interactions. Hydroxylamine-reduced NPs required slight aggregation and no pH modifications in order to obtain high spectral quality results in bringing out SERS signatures of Bt.

  3. Variation in the binding of 125I-labeled interferon-beta ser to cellular receptors during growth of human renal and bladder carcinoma cells in vitro

    International Nuclear Information System (INIS)

    Ruzicka, F.J.; Schmid, S.M.; Groveman, D.S.; Cummings, K.B.; Borden, E.C.

    1987-01-01

    Studies of various established human bladder and renal carcinoma cell lines cultured in vitro demonstrated the presence of specific, saturable, high affinity binding sites for 125 I-labeled human interferon Beta ser IFN-beta ser). This recombinant produced interferon labeled with approximately one atom of 125 I/molecule of IFN expressed minimal or no loss of antiviral activity. A single class of binding sites (1000-2000/cell) with an affinity constant of 10(10)-10(11) L/M was measured at 4 degrees C for cells exhibiting widely different sensitivity to the antiproliferative effect of IFN-beta ser. Major fluctuations in the binding of 125 I-labeled IFN-beta ser to cellular receptors were observed during in vitro proliferation of four of five cell lines examined. A significant decrease (P less than 0.001) in specific binding was observed 48 h after cultures were established. Cell cycle analysis suggested that within the first 24 h and in the very late log and stationary phase of growth of ACHN (human renal carcinoma) cells, variations in the binding of 125 I-labeled IFN-beta ser were partially attributable to binding fluctuations during the mitotic cycle. The 2- to 3-fold decline 24 h following plating of ACHN cells corresponded to a 70% decrease in the number of cells in G0-G1. T24 (human transitional cell carcinoma) and ACHN cells, synchronized by serum starvation, demonstrated increased binding of 125 I-labeled IFN-beta ser 4-16 h following serum replenishment. This increase in receptor binding occurred prior to the onset of DNA and protein synthesis and was followed by a decline immediately prior to cell division. Binding site analysis indicated that the increased binding prior to DNA synthesis was due to a 5- to 6-fold increase in receptor affinity for the radiolabeled ligand

  4. SERS microscopy: plasmonic nanoparticle probes and biomedical applications

    Science.gov (United States)

    Gellner, M.; Schütz, M.; Salehi, M.; Packeisen, J.; Ströbel, P.; Marx, A.; Schmuck, C.; Schlücker, S.

    2010-08-01

    Nanoparticle probes for use in targeted detection schemes and readout by surface-enhanced Raman scattering (SERS) comprise a metal core, Raman reporter molecules and a protective shell. One design of SERS labels specifically optimized for biomedical applications in conjunction with red laser excitation is based on tunable gold/silver nanoshells, which are completely covered by a self-assembled monolayer (SAM) of Raman reporters. A shell around the SAM-coated metal core stabilizes the colloid and prevents particle aggregation. The optical properties and SERS efficiencies of these plasmonic nanostructures are characterized both experimentally and theoretically. Subsequent bioconjugation of SERS probes to ligands such as antibodies is a prerequisite for the selective detection of the corresponding target molecule via the characteristic Raman signature of the label. Biomedical imaging applications of SERS-labeled antibodies for tumor diagnostics by SERS microscopy are presented, using the localization of the tumor suppressor p63 in prostate tissue sections as an example.

  5. A practicable detection system for genetically modified rice by SERS-barcoded nanosensors.

    Science.gov (United States)

    Chen, Kun; Han, Heyou; Luo, Zhihui; Wang, Yanjun; Wang, Xiuping

    2012-04-15

    Since the global cultivation of genetically modified crops constantly expands, it remains a high demand to establish different ways to sort food and feed that consist or contain genetically modified organisms. Surface-enhanced Raman scattering (SERS) spectroscopy is a flexible tool for biological analysis due to its excellent properties for detecting wide varieties of target biomolecules including nucleic acids. In the present study, a SERS-barcoded nanosensor was developed to detect Bacillus thuringiensis (Bt) gene-transformed rice expressing insecticidal proteins. The barcoded sensor was designed by encapsulation of gold nanoparticles with silica and conjugation of oligonucleotide strands for targeting DNA strands. The transition between the cry1A(b) and cry1A(c) fusion gene sequence was used to construct a specific SERS-based detection method with a detection limit of 0.1 pg/mL. In order to build the determination models to screen transgene, a series mixture of Bt rice and normal rice were prepared for SERS assay, and the limit of detection was 0.1% (w/w) transgenic Bt rice relative to normal rice. The sensitivity and accuracy of the SERS-based assay was comparable with real-time PCR. The SERS-barcoded analytical method would provide precise detection of transgenic rice varieties but also informative supplement to avoid false positive outcomes. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  6. Label-free SERS in biological and biomedical applications: Recent progress, current challenges and opportunities

    Science.gov (United States)

    Zheng, Xiao-Shan; Jahn, Izabella Jolan; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2018-05-01

    To achieve an insightful look within biomolecular processes on the cellular level, the development of diseases as well as the reliable detection of metabolites and pathogens, a modern analytical tool is needed that is highly sensitive, molecular-specific and exhibits fast detection. Surface-enhanced Raman spectroscopy (SERS) is known to meet these requirements and, within this review article, the recent progress of label-free SERS in biological and biomedical applications is summarized and discussed. This includes the detection of biomolecules such as metabolites, nucleic acids and proteins. Further, the characterization and identification of microorganisms has been achieved by label-free SERS-based approaches. Eukaryotic cells can be characterized by SERS in order to gain information about the outer cell wall or to detect intracellular molecules and metabolites. The potential of SERS for medically relevant detection schemes is emphasized by the label-free detection of tissue, the investigation of body fluids as well as applications for therapeutic and illicit drug monitoring. The review article is concluded with an evaluation of the recent progress and current challenges in order to highlight the direction of label-free SERS in the future.

  7. Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate

    Directory of Open Access Journals (Sweden)

    Shavini Wijesuriya

    2016-10-01

    Full Text Available Surface-enhanced Raman spectroscopy (SERS substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH4OH and nitric acid (HNO3 helped obtain roughened Ag SERS substrates. Scanning electron microscopy (SEM and interferometry were used to visualize and quantify surface roughness. Flattened Ag wires had inherent, but non-uniform roughness having peaks and valleys in the microscale. NH4OH treatment removed dirt and smoothened the surface, while HNO3 treatment produced a flake-like morphology with visibly more surface roughness features on Ag metal. SERS efficacy was tested using 4-methylbenzenethiol (MBT. The best SERS enhancement for 1 mM MBT was observed for Ag metal etched for 30 s in NH4OH followed by 10 s in HNO3. Further, MBT could be quantified with detection limits of 1 pM and 100 µM, respectively, using 514 nm and 1064 nm Raman spectrometers. Thus, a rapid and less energy intensive method for producing solid Ag SERS substrate and its efficacy in analyte sensing was demonstrated.

  8. Synthesis of Dendritic Silver Nanoparticles and Their Applications as SERS Substrates

    Directory of Open Access Journals (Sweden)

    Jinshan Yu

    2013-01-01

    Full Text Available The silver nanoparticles are synthesized by electrodeposition in ultradilute Ag+ concentration electrolyte under high overpotential. The as prepared Ag nanoparticles, with the sizes ranging from 20 to 30 nm, are arrayed orderly and formed dendritic morphology. The formation of this special dendritic nanoparticle structure can be contributed to the relatively high growth rate and the preferential growth directions along 111 due to the high overpotential, as well as the relative small number of Ag+ ions arriving at the Ag crystal surface per unit time due to the ultradilute Ag+ concentration. Surface enhanced Raman scattering (SERS experiments reveal that the as-prepared dendritic Ag nanoparticles possess high SERS properties and can be used as a candidate substrate for practical SERS applications to detect the Rhodamine 6G molecules.

  9. An improved 99mTc-HYNIC-(Ser)3-LTVSPWY peptide with EDDA/tricine as co-ligands for targeting and imaging of HER2 overexpression tumor.

    Science.gov (United States)

    Khodadust, Fatemeh; Ahmadpour, Sajjad; Aligholikhamseh, Nazan; Abedi, Seyed Mohammad; Hosseinimehr, Seyed Jalal

    2018-01-20

    Overexpression of human epidermal receptor 2 (HER2) has given the opportunity for targeting and delivering of imaging radiotracers. The aim of this study was to evaluate the 99m Tc-HYNIC-(EDDA/tricine)-(Ser) 3 -LTVSPWY peptide for tumor targeting and imaging of tumor with overexpression of HER2. The HYNIC-(Ser) 3 -LTVSPWY was labeled with 99m Tc in presence of EDDA/tricine mixture as co-ligands. The in vitro and in vivo studies of this radiolabeled peptide were performed for cellular specific binding and tumor targeting. The high radiochemical purity of 99m Tc-HYNIC (EDDA/tricine)-(Ser) 3 -LTVSPWY was obtained to be 99%. It exhibited high stability in normal saline and human serum. In HER2 binding affinity study, a significant reduction in uptake of radiolabeled peptide (7.7 fold) was observed by blocking SKOV-3 cells receptors with unlabeled peptide. The K D and B max values for this radiolabeled peptide were determined as 3.3 ± 1.0 nM and 2.9 ± 0.3 × 10 6 CPM/pMol, respectively. Biodistribution study revealed tumor to blood and tumor to muscle ratios about 6.9 and 4 respectively after 4 h. Tumor imaging by gamma camera demonstrated considerable high contrast tumor uptake. This developed 99m Tc-HYNIC-(Ser) 3 -LTVSPWY peptide selectively targeted on HER2 tumor and exhibited a high target uptake combined with acceptable low background activity for tumor imaging in mice. The results of this study and its comparison with another study showed that 99m Tc-HYNIC-(EDDA/tricine)-(Ser) 3 -LTVSPWY is much better than previously reported radiolabeled peptide as 99m Tc-CSSS-LTVSPWY for HER2 overexpression tumor targeting and imaging. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. Nanofabrication of SERS Substrates for Single/Few Molecules Detection

    KAUST Repository

    Melino, Gianluca

    2015-05-04

    Raman spectroscopy is among the most widely employed methods to investigate the properties of materials in several fields of study. Evolution in materials science allowed us to fabricate suitable substrates, at the nanoscale, capable to enhance the electromagnetic field of the signals coming from the samples which at this range turn out to be in most cases singles or a few molecules. This particular variation of the classical technique is called SERS (Surface Enanched Raman Spectroscopy). In this work, the enhancement of the electromagnetic field is obtained by manipulation of the optical properties of metals with respect to their size. By using electroless deposition (bottom up technique), gold and silver nanoparticles were deposited in nanostructured patterns obtained on silicon wafers by means of electron beam lithography (top down technique). Rhodamine 6G in aqueous solution at extremely low concentration (10-8 M) was absorbed on the resultant dimers and the collection of the Raman spectra demonstrated the high efficiency of the substrates.

  11. A study on the correlation between the dewetting temperature of Ag film and SERS intensity.

    Science.gov (United States)

    Quan, Jiamin; Zhang, Jie; Qi, Xueqiang; Li, Junying; Wang, Ning; Zhu, Yong

    2017-11-07

    The thermally dewetted metal nano-islands have been actively investigated as cost-effective SERS-active substrates with a large area, good reproducibility and repeatability via simple fabrication process. However, the correlation between the dewetting temperature of metal film and SERS intensity hasn't been systematically studied. In this work, taking Ag nano-islands (AgNIs) as an example, we reported a strategy to investigate the correlation between the dewetting temperature of metal film and SERS intensity. We described the morphology evolution of AgNIs on the SiO 2 planar substrate in different temperatures and got the quantitative information in surface-limited diffusion process (SLDP) as a function of annealing temperature via classical mean-field nucleation theory. Those functions were further used in the simulation of electromagnetic field to obtain the correlation between the dewetting temperature of Ag film and theoretical analysis. In addition, Raman mapping was done on samples annealed at different temperatures, with R6G as an analyte, to accomplish the analysis of the correlation between the dewetting temperature of Ag film and SERS intensity, which is consistent with the theoretical analysis. For SLDP, we used the morphological characterization of five samples prepared by different annealing temperatures to successfully illustrate the change in SERS intensity with the temperature fluctuation, obtaining a small deviation between the experimental results and theoretic prediction.

  12. Myofilament Calcium Sensitivity: Mechanistic Insight into TnI Ser-23/24 and Ser-150 Phosphorylation Integration

    Directory of Open Access Journals (Sweden)

    Hussam E Salhi

    2016-12-01

    Full Text Available Troponin I (TnI is a major regulator of cardiac muscle contraction and relaxation. During physiological and pathological stress, TnI is differentially phosphorylated at multiple residues through different signaling pathways to match cardiac function to demand. The combination of these TnI phosphorylations can exhibit an expected or unexpected functional integration, whereby the function of two phosphorylations are different than that predicted from the combined function of each individual phosphorylation alone. We have shown that TnI Ser-23/24 and Ser-150 phosphorylation exhibit functional integration and are simultaneously increased in response to cardiac stress. In the current study, we investigated the functional integration of TnI Ser-23/24 and Ser-150 to alter cardiac contraction. We hypothesized that Ser-23/24 and Ser-150 phosphorylation each utilize distinct molecular mechanisms to alter the TnI binding affinity within the thin filament. Mathematical modeling predicts that Ser-23/24 and Ser-150 phosphorylation affect different TnI affinities within the thin filament to distinctly alter the Ca2+-binding properties of troponin. Protein binding experiments validate this assertion by demonstrating pseudo-phosphorylated Ser-150 decreases the affinity of isolated TnI for actin, whereas Ser-23/24 pseudo-phosphorylation is not different from unphosphorylated. Thus, our data supports that TnI Ser-23/24 affects TnI-TnC binding, while Ser-150 phosphorylation alters TnI-actin binding. By measuring force development in troponin-exchanged skinned myocytes, we demonstrate that the Ca2+ sensitivity of force is directly related to the amount of phosphate present on TnI. Furthermore, we demonstrate that Ser-150 pseudo-phosphorylation blunts Ser-23/24-mediated decreased Ca2+-sensitive force development whether on the same or different TnI molecule. Therefore, TnI phosphorylations can integrate across troponins along the myofilament. These data demonstrate

  13. QUE É O "SER DA FAMÍLIA"?

    Directory of Open Access Journals (Sweden)

    Josefa Aida Delgado

    2005-01-01

    Full Text Available Es un estudio basado en la filosofía fenomenológica heideggeriana, su propósito es desvelar los elementos estructurales de la existencia del "ser de la familia". El camino metodológico fue construido con base en el pensamiento de Heidegger. Los datos de la familia fueron recolectados por medio de las entrevistas y las observaciones. Cada uno de nosotros contribuye para su existencia, y ella posibilita el desarrollo de nuestro "ser-en el-mundo" al vivenciar y compartir experiencias cotidianas de la familia. Allí surge la posibilidad de compartir un modo de ser en el mundo, un modo de cuidado para "ser familia en el mundo". Un mundo que genera esa unidad de relacionamiento que emerge de sentimientos interligados entre los integrantes, respondiendo a las exigencias de cada miembro, por el sentimiento de pertenencia primaria generado en ellos. Esa unidad da la posibilidad de nacer a cada uno de nosotros, asi también, nos da la posibilidad de poder ser ser humano, llegando a ser un referencial de sí misma en cada ser humano.

  14. IR, Raman and SERS studies of methyl salicylate

    Science.gov (United States)

    Varghese, Hema Tresa; Yohannan Panicker, C.; Philip, Daizy; Mannekutla, James R.; Inamdar, S. R.

    2007-04-01

    The IR and Raman spectra of methyl salicylate (MS) were recorded and analysed. Surface enhanced Raman scattering (SERS) spectrum was recorded in silver colloid. The vibrational wave numbers of the compound have been computed using the Hartree-Fock/6-31G * basis and compared with the experimental values. SERS studies suggest a flat orientation of the molecule at the metal surface.

  15. Association of the hOGG1 Ser326Cys polymorphism with sporadic amyotrophic lateral sclerosis.

    Science.gov (United States)

    Coppedè, Fabio; Mancuso, Michelangelo; Lo Gerfo, Annalisa; Carlesi, Cecilia; Piazza, Selina; Rocchi, Anna; Petrozzi, Lucia; Nesti, Claudia; Micheli, Dario; Bacci, Andrea; Migliore, Lucia; Murri, Luigi; Siciliano, Gabriele

    2007-06-13

    Amyotropic lateral sclerosis (ALS) is a fatal and progressive neurodegenerative disease causing the loss of motoneurons of the brain and the spinal cord. The etiology of ALS is still uncertain, but males are at increased risk for the disease than females. Several studies have suggested that motoneurons in ALS might be subjected to the double insult of increased DNA oxidative damage and deficiencies in DNA repair systems. Particularly, increased levels of 8-oxoguanine and impairments of the DNA base excision repair system have been observed in neurons of ALS patients. There is evidence that the Ser326Cys polymorphism of the human 8-oxoguanine DNA glycosylase 1 (hOGG1) gene is associated with a reduced DNA repair activity. To evaluate the role of the hOGG1 Ser326Cys polymorphism in sporadic ALS (sALS), we screened 136 patients and 129 matched controls. In the total population, we observed association between both the Cys326 allele (p=0.02) and the combined Ser326Cys+Cys326Cys genotype (OR=1.65, 95% CI=1.06-2.88) and increased risk of disease. After stratification by gender, the Cys326 allele (p=0.01), both the Ser326Cys genotype (OR=2.14, 95% CI=1.09-4.19) and the combined Ser326Cys+Cys326Cys genotype (OR=2.15, 95% CI=1.16-4.01) were associated with sALS risk only in males. No significant association between the Ser326Cys polymorphism and disease phenotype, including age and site of onset and disease progression, was observed. Present results suggest a possible involvement of the hOGG1 Ser326Cys polymorphism in sALS pathogenesis.

  16. Social capital and physical activity among Croatian high school students.

    Science.gov (United States)

    Novak, D; Doubova, S V; Kawachi, I

    2016-06-01

    To examine factors associated with regular physical activity in Croatian adolescents. A cross-sectional survey among high school students was carried out in the 2013/14 school year. A survey was conducted among 33 high schools in Zagreb City, Croatia. Participants were students aged 17-18 years. The dependent variables were regular moderate to vigorous physical activity (MVPA) and overall physical activity measured by the short version of International Physical Activity Questionnaire and defined as 60 min or more of daily physical activity. The independent variables included family, neighborhood, and high school social capital. Other study covariates included: socio-economic status, self-rated health, psychological distress and nutritional status. The associations between physical activity and social capital variables were assessed separately for boys and girls through multiple logistic regression and inverse probability weighting in order to correct for missing data bias. A total of 1689 boys and 1739 girls responded to the survey. A higher percentage of boys reported performing regular vigorous and moderate physical activity (59.4%) and overall physical activity (83.4%), comparing with the girls (35.4% and 70%, respectively). For boys, high family social capital and high informal social control were associated with increased odds of regular MVPA (1.49, 95%CI: 1.18 - 1.90 and 1.26, 95%CI: 1.02 - 1.56, respectively), compared to those with low social capital. For girls, high informal social control was associated with regular overall physical activity (OR 1.38, 95% CI: 1.09 - 1.76). High social capital is associated with regular MVPA in boys and regular overall activity in girls. Intervention and policies that leverage community social capital might serve as an avenue for promotion of physical activity in youth. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  17. Preparation and SERS performance of Au NP/paper strips based on inkjet printing and seed mediated growth: The effect of silver ions

    Science.gov (United States)

    Weng, Guojun; Yang, Yue; Zhao, Jing; Zhu, Jian; Li, Jianjun; Zhao, Junwu

    2018-04-01

    Surface-enhanced Raman scattering (SERS) has been widely used in biomedical sensing with the advantages of high sensitivity and label-free. However, the fabrication of SERS substrates with good Raman activity, reproducibility, and low cost is still under development in practical applications. This paper presents a practicable method for fabricating Au NP/paper strips by using inkjet printing and seed mediated growth. Small gold seed synthesized by borohydride reduction was used as ink and printed on the filter paper. The printed gold seed grew in situ in the growth solution and formed the gold nanoparticle (Au NP)/paper strips. The fabricated paper strip was characterized by diffuse reflectance spectroscopy and scanning electron microscopy (SEM). The diffuse reflectance spectra indicated that the Au NP/paper strips had two local surface plasmon resonance (LSPR) peaks: the short one at around 540 nm and the long one located in the range of 640-840 nm. And the long LSPR peak firstly shifted to red then to blue with the increased concentrations of silver ions in growth solution. From the SEM images, the shape of grown Au NPs was diverse, including sphere, rod, ellipsoid, dimer, trimer, and big aggregates. We thought the short peak came from the LSPR of nanospheres and the transvers LSPR of rod and ellipsoid like particles, while the long peak mainly came from the plasmonic coupling of dimer along the inter-particle axis. The obtained Au NP/paper strip with the long peak located around 650 nm had the highest SERS activity, which could be attributed to the plasmon resonance induced local field enhancement and nanogap effect. Also, the SERS performance results indicated the printed SERS strips exhibited satisfied uniformity and stability, demonstrating the potential of Au NP/paper strip in real-world applications.

  18. Active Gaming Among High School Students--United States, 2010.

    Science.gov (United States)

    Song, MinKyoung; Carroll, Dianna D; Lee, Sarah M; Fulton, Janet E

    2015-08-01

    Our study is the first to describe the prevalence and correlates (demographics, body mass index [BMI], sedentary behaviors, and physical activity) of high school youth who report active videogame playing (active gaming) in a U.S. representative sample. The National Youth Physical Activity and Nutrition Study of 2010 provided data for this study. Active gaming was assessed as the number of days in the 7 days prior to the survey that students in grades 9-12 (14-18 years of age) reported participating in active videogames (e.g., "Wii™ Fit" [Nintendo, Kyoto, Japan], "Dance Dance Revolution" [Konami, Osaka, Japan]). Students reporting ≥1 days were classified as active gamers. Logistic regression was used to examine the association among active gaming and demographic characteristics, BMI, sedentary behaviors, and physical activity. Among 9125 U.S. high school students in grades 9-12 surveyed, 39.9 percent (95 percent confidence interval=37.9 percent, 42.0 percent) reported active gaming. Adjusting for covariates, the following characteristics were positively associated (Pblack, non-Hispanic race/ethnicity; being overweight or obese; watching DVDs >0 hours/day; watching TV >0 hours/day; and meeting guidelines for aerobic and muscle-strengthening physical activity. Four out of 10 U.S. high school students report participating in active gaming. Active gamers tend to spend more time watching DVDs or TV, meet guidelines for physical activity, and/or be overweight or obese compared with nonactive gamers. These findings may serve to provide a baseline to track active gaming in U.S. youth and inform interventions that target sedentary behaviors and/or physical activity.

  19. Physical activity behavior and related characteristics of highly active eighth-grade girls.

    Science.gov (United States)

    Taverno Ross, Sharon E; Dowda, Marsha; Beets, Michael W; Pate, Russell R

    2013-06-01

    Although girls are generally less physically active than boys, some girls regularly engage in high levels of physical activity (PA); however, very little is known about these girls and how they differ from those who are less physically active. This study examined the PA behavior and related characteristics of highly active adolescent girls and compared them with those who are less active. Data from 1,866 eighth-grade girls from six field centers across the United States participating in the Trial of Activity for Adolescent Girls (TAAG) were included in the present analysis. Mixed-model analysis of variance examined differences in sociodemographic, anthropometric, psychosocial, and physical activity (accelerometry and self-report) variables between high- and low-active girls; effect sizes were calculated for the differences. High-active girls were taller, had lower body mass indices and body fat, and were less sedentary. High-active girls scored higher on self-efficacy, enjoyment of PA, self-management strategies, outcome-expectancy value, and support from family and friends than low-active girls. Low-active girls participated in more leisure time and educational sedentary activities than high-active girls. High-active girls participated in more PA classes/lessons outside of school, team sports, and individual sports. They were also more likely to participate in sports in an organized setting in the community or at school than low-active girls. Health promotion efforts should focus on decreasing the amount of time girls spend in sedentary activities and replacing that time with organized PA opportunities; such efforts should seek to minimize perceived barriers and increase self-efficacy and support for PA. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  20. SERS spectra of pyridine adsorbed on nickel film prepared by magnetron sputtering

    Science.gov (United States)

    Li, Daoyong; Ouyang, Yu; Chen, Li; Cao, Weiran; Shi, Shaohua

    2011-02-01

    As a repeating well and cheaper enhancement substrate, the nickel film was fabricated with magnetron sputtering coating instrument. Surface enhanced Raman spectra (SERS) of pyridine adsorbed on this nickel film are compared with the experimental values of gaseous pyridine, the theoretical value of pyridine solution listed in other literatures and our method is better than electro-chemical etching electrode method for large scale preparation. The enhancement factor of the nickel film is calculated and the result indicates that magnetron sputtering coating technology is feasible for obtaining good SERS active surface.

  1. Facile synthesis of Ag dendrites on Al foil via galvanic replacement reaction with [Ag(NH3)2]Cl for ultrasensitive SERS detecting of biomolecules

    International Nuclear Information System (INIS)

    Fu, Jiajia; Ye, Weichun; Wang, Chunming

    2013-01-01

    Symmetric silver dendrites have been synthesized on commercial aluminum foil via galvanic replacement reaction with [Ag(NH 3 ) 2 ]Cl. This process is facile and environmentally friendly, without the use of any templates, surfactants or oxidants, and also avoiding the introduction of fluoride anions as a strong toxicity resulting in hypocalcemia. The products were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and X-ray diffraction (XRD). SEM characterizations and electrochemical measurements including an electrochemical direct current polarization method and OCP-t technique demonstrate that chloride has proven to be the key factor to the formation of well-defined dendritic shape. The as-prepared Ag dendrites are developed as a surface-enhanced Raman scattering (SERS)-active platform for detection of folic acid, DNA and RNA with well resolved bands and high Raman intensities. The detection concentration for the three biomolecules reaches the level of 10 −12 M, and thus the symmetric silver dendrites can potentially be employed as effective SERS sensors for label-free and ultrasensitive biomolecule detection. - Highlights: • Simple galvanic replacement is used to synthesize Ag dendrites on commercial Al foils. • This method avoids the introduction of fluoride anions. • The as-prepared dendrites exhibit high SERS activities for biomolecules. • The detection concentration for the biomolecules reaches the level of 10 −12 M

  2. Facile synthesis of Ag dendrites on Al foil via galvanic replacement reaction with [Ag(NH{sub 3}){sub 2}]Cl for ultrasensitive SERS detecting of biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiajia; Ye, Weichun [Department of Chemistry, Lanzhou University, Lanzhou 73000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 73000 (China); Wang, Chunming, E-mail: wangcm@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 73000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 73000 (China)

    2013-08-15

    Symmetric silver dendrites have been synthesized on commercial aluminum foil via galvanic replacement reaction with [Ag(NH{sub 3}){sub 2}]Cl. This process is facile and environmentally friendly, without the use of any templates, surfactants or oxidants, and also avoiding the introduction of fluoride anions as a strong toxicity resulting in hypocalcemia. The products were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and X-ray diffraction (XRD). SEM characterizations and electrochemical measurements including an electrochemical direct current polarization method and OCP-t technique demonstrate that chloride has proven to be the key factor to the formation of well-defined dendritic shape. The as-prepared Ag dendrites are developed as a surface-enhanced Raman scattering (SERS)-active platform for detection of folic acid, DNA and RNA with well resolved bands and high Raman intensities. The detection concentration for the three biomolecules reaches the level of 10{sup −12} M, and thus the symmetric silver dendrites can potentially be employed as effective SERS sensors for label-free and ultrasensitive biomolecule detection. - Highlights: • Simple galvanic replacement is used to synthesize Ag dendrites on commercial Al foils. • This method avoids the introduction of fluoride anions. • The as-prepared dendrites exhibit high SERS activities for biomolecules. • The detection concentration for the biomolecules reaches the level of 10{sup −12} M.

  3. Activities of everyday life with high spinal loads.

    Directory of Open Access Journals (Sweden)

    Antonius Rohlmann

    Full Text Available Activities with high spinal loads should be avoided by patients with back problems. Awareness about these activities and knowledge of the associated loads are important for the proper design and pre-clinical testing of spinal implants. The loads on an instrumented vertebral body replacement have been telemetrically measured for approximately 1000 combinations of activities and parameters in 5 patients over a period up to 65 months postoperatively. A database containing, among others, extreme values for load components in more than 13,500 datasets was searched for 10 activities that cause the highest resultant force, bending moment, torsional moment, or shear force in an anatomical direction. The following activities caused high resultant forces: lifting a weight from the ground, forward elevation of straight arms with a weight in hands, moving a weight laterally in front of the body with hanging arms, changing the body position, staircase walking, tying shoes, and upper body flexion. All activities have in common that the center of mass of the upper body was moved anteriorly. Forces up to 1650 N were measured for these activities of daily life. However, there was a large intra- and inter-individual variation in the implant loads for the various activities depending on how exercises were performed. Measured shear forces were usually higher in the posterior direction than in the anterior direction. Activities with high resultant forces usually caused high values of other load components.

  4. SERS study of transformation of phenylalanine to tyrosine under particle irradiation

    Science.gov (United States)

    Zhang, Jingjing; Huang, Qing; Yao, Guohua; Ke, Zhigang; Zhang, Hong; Lu, Yilin

    2014-08-01

    Surface enhanced Raman scattering or spectroscopy (SERS) is a very powerful analytical tool which has been widely applied in many scientific research and application fields. It is therefore also very intriguing for us to introduce SERS technique in the radiobiological research, where in many cases only a very few of biomolecules are subjected to changes which however can lead to significant biological effects. The radiation induced biochemical reactions are normally very sophisticated with different substances produced in the system, so currently it is still a big challenge for SERS to analyze such a mixture system which contains multiple analytes. In this context, this work aimed to establish and consolidate the feasibility of SERS as an effective tool in radiation chemistry, and this purpose, we employed SERS as a sensitive probe to a known process, namely, the oxidation of phenylalanine (Phe) under particle irradiation, where the energetic particles were obtained from either plasma discharge or electron-beam. During the irradiation, three types of tyrosine (Tyr), namely, p-Tyr, m-Tyr and o-Tyr were produced, and all these tyrosine isomers together with Phe could be identified and measured based on the SERS spectral analysis of the corresponding enhanced characteristic signals, namely, 1002 cm-1 for Phe, 1161 cm-1 for p-Tyr, 990 cm-1 for m-Tyr, and 970 cm-1 for o-Tyr, respectively. The estimation of the quantities of different tyrosine isomers were also given and verified by conventional method such as high performance liquid chromatography (HPLC). As for comparison of different ways of particle irradiation, our results also indicated that electron-beam irradiation was more efficient for converting Phe into Tyr than plasma discharge treatment, confirming the role of hydroxyl radicals in the Phe-Tyr conformation. Therefore, our work has not only demonstrated that SERS can be successfully applied in the radiobiological study, but also given insights into the

  5. Effect of the size of silver nanoparticles on SERS signal enhancement

    Science.gov (United States)

    He, Rui Xiu; Liang, Robert; Peng, Peng; Norman Zhou, Y.

    2017-08-01

    The localized surface plasmon resonance arising from plasmonic materials is beneficial in solution-based and thin-film sensing applications, which increase the sensitivity of the analyte being tested. Silver nanoparticles from 35 to 65 nm in diameter were synthesized using a low-temperature method and deposited in a monolayer on a (3-aminopropyl)triethoxysilane (APTES)-functionalized glass slide. The effect of particle size on monolayer structure, optical behavior, and surface-enhanced Raman scattering (SERS) is studied. While increasing particle size decreases particle coverage, it also changes the localized surface plasmon resonance and thus the SERS activity of individual nanoparticles. Using a laser excitation wavelength of 633 nm, the stronger localized surface plasmon resonance coupling to this excitation wavelength at larger particle sizes trumps the loss in surface coverage, and greater SERS signals are observed. The SERS signal enhancement accounts for the higher SERS signal, which was verified using a finite element model of a silver nanoparticle dimer with various nanoparticle sizes and separation distances.

  6. Effects of surface topography on SERS response: Correlating nanoscopy with spectroscopy

    Science.gov (United States)

    Das, Sumit Kumar; Ghosh, Manash; Chowdhury, Joydeep

    2018-05-01

    This paper reports for the first time the hidden correlation between the topographical features of the bilayer Langmuir-Blodgett (LB) film substrates of stearic acid (SA) incubated in Au@Ag nanocolloids over various dipping times (DTs) with their corresponding SERS responses. The topographies of the as prepared substrates are investigated from the statistical considerations in terms of lateral correlation length, interface width, Hurst and Lyapnov exponents. The real space of the substrates are mapped directly from the FESEM and AFM images of the bilayer LB film of SA immersed in Au@Ag nanocolloids over various DTs ranging between 6 and 72 h. The SERS spectra of the Rhodamine 6G molecules adsorbed on the as prepared substrates have been reported. The statistical parameters of the substrates that exhibit maximum SERS efficacy have been suggested. The far field distributions in presence and in absence of Raman dipole together with spatial distribution of the near field from the hottest spot of the as prepared substrate have also been reported. To our knowledge, this is the first report that links nanoscopy with SERS spectroscopy from statistical considerations and is expected to open a new window towards the fabrication of more efficient and reproducible SERS active substrates in future endeavours.

  7. Controllable Ag nanostructure patterning in a microfluidic channel for real-time SERS systems.

    Science.gov (United States)

    Leem, Juyoung; Kang, Hyun Wook; Ko, Seung Hwan; Sung, Hyung Jin

    2014-03-07

    We present a microfluidic patterning system for fabricating nanostructured Ag thin films via a polyol method. The fabricated Ag thin films can be used immediately in a real-time SERS sensing system. The Ag thin films are formed on the inner surfaces of a microfluidic channel so that a Ag-patterned Si wafer and a Ag-patterned PDMS channel are produced by the fabrication. The optimum sensing region and fabrication duration for effective SERS detection were determined. As SERS active substrates, the patterned Ag thin films exhibit an enhancement factor (EF) of 4.25 × 10(10). The Ag-patterned polymer channel was attached to a glass substrate and used as a microfluidic sensing system for the real-time monitoring of biomolecule concentrations. This microfluidic patterning system provides a low-cost process for the fabrication of materials that are useful in medical and pharmaceutical detection and can be employed in mass production.

  8. Synthesis by picosecond laser ablation of ligand-free Ag and Au nanoparticles for SERS applications

    Science.gov (United States)

    Fazio, Enza; Spadaro, Salvatore; Santoro, Marco; Trusso, Sebastiano; Lucotti, Andrea.; Tommasini, Matteo.; Neri, Fortunato; Maria Ossi, Paolo

    2018-01-01

    The morphological and optical properties of noble metal nanoparticles prepared by picosecond laser generated plasmas in water were investigated. First, the ablation efficiency was maximized searching the optimal focusing conditions. The nanoparticle size, measured by Scanning Transmission Electron Microscopy, strongly depends on the laser fluence, keeping fixed the other deposition parameters such as the target to scanner objective distance and laser repetition frequency. STEM images indicate narrow gradients of NP sizes. Hence the optimization of ablation parameters favours a fine tuning of nanoparticles. UV-Visible spectroscopy helped to determine the appropriate laser wavelength to resonantly excite the localized surface plasmon to carry out Surface Enhanced Raman Scattering (SERS) measurements. The SERS activity of Ag and Au substrates, obtained spraying the colloids synthesized in water, was tested using crystal violet as a probe molecule. The good SERS performance, observed at excitation wavelength 785 nm, is attributed to aggregation phenomena of nanoparticles sprayed on the support.

  9. Roles of family dynamics on adherence to highly active antiretroviral ...

    African Journals Online (AJOL)

    EB

    Background: Adherence to highly active antiretroviral therapy (HAART) has been proven .... Table 1: Relationship between socio-demographic characteristics and HAART adherence among ... constraints (44%), stigma (15%), travel/migration.

  10. Feasibility of High Energy Lasers for Interdiction Activities

    Science.gov (United States)

    2017-12-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS FEASIBILITY OF HIGH ENERGY LASERS FOR INTERDICTION ACTIVITIES by Carlos Abel Javier Romero... ENERGY LASERS FOR INTERDICTION ACTIVITIES 5. FUNDING NUMBERS 6. AUTHOR(S) Carlos Abel Javier Romero Chero 7. PERFORMING ORGANIZATION NAME(S) AND...the people or cargo. High Energy Laser (HEL) weapons are an effective way to deliver energy precisely from a relative long range. This thesis studies

  11. Human Spaceflight: Activities for the Intermediate and Junior High Student.

    Science.gov (United States)

    Hartsfield, John W.; Hartsfield, Kendra J.

    Since its beginning, space science has created high interest and continues to prod the imagination of students. This activity packet, which has been designed to enhance the curriculum and challenge gifted students, contains background information on spaceflight as well as 24 interdisciplinary classroom activities, 3 crossword puzzles, and 3 word…

  12. Synergistic effects of semiconductor substrate and noble metal nano-particles on SERS effect both theoretical and experimental aspects

    Science.gov (United States)

    Yang, Chen; Liang, Pei; Tang, Lisha; Zhou, Yongfeng; Cao, Yanting; Wu, Yanxiong; Zhang, De; Dong, Qianmin; Huang, Jie; He, Peng

    2018-04-01

    As a means of chemical identification and analysis, Surface enhanced Raman spectroscopy (SERS), with the advantages of high sensitivity and selectivity, non-destructive, high repeatability and in situ detection etc., has important significance in the field of composition detection, environmental science, biological medicine etc. Physical model of coupling effect between different semiconductor substrates and noble metal particles were investigated by using 3D-FDTD method. Mechanism and the effects of excitation wavelength, particle spacing and semiconductor substrate types on the SERS effect were discussed. The results showed that the optimal excitation wavelengths of three noble metals of Ag, Au, Cu, were located at 510, 600 and 630 nm, respectively; SERS effect of Ag, Au, Cu increases with the decreasing of the inter distance of particles, while the distance of the NPs reaches the critical value of 3 nm, the strength of SERS effect will be greatly enhanced. For the four different types of substrate of Ge, Si, SiO2 (glass) and Al2O3, the SERS effect of Ag on SiO2 > Ge > Al2O3 > Si. For Au and Cu nanoparticles, the SERS effect of them on oxide substrate is stronger than that on non-oxide substrate. In order to verify FDTD simulations, taking silver nanoparticles as an example, and silver nanoparticles prepared by chemical method were spinning coating on the four different substrates with R6G as probe molecules. The results show that the experimental results are consistent with FDTD theoretical simulations, and the SERS enhancement effect of Ag-SiO2 substrate is best. The results of this study have important theoretical significance to explain the variations of SERS enhancement on different noble metals, which is also an important guide for the preparation of SERS substrates, especially for the microfluidics. The better Raman effect can be realized by choosing proper substrate type, particle spacing and excitation wavelength, result in expanding the depth and width

  13. Development of optimized nanogap plasmonic substrate for improved SERS enhancement

    Directory of Open Access Journals (Sweden)

    Jayakumar Perumal

    2017-05-01

    Full Text Available SERS enhancement factor (EF of planar substrates depends on the size and shape of the fine nanostructure forming a defect free, well-arranged matrix. Nano-lithographic process is considered to be the most advanced methods employed for the fabrication SERS substrates. Nanostructured plasmonic substrates with nanogap (NG pattern often results in stable, efficient and reproducible SERS enhancement. For such substrates, NG and their diagonal length (DL need to be optimized. Theoretically smaller NGs (∼30-40 nm or smaller results in higher SERS enhancement. However, fabrication of NG substrates below such limit is a challenge even for the most advanced lithography process. In this context, herein, we report the optimization of fabrication process, where higher SERS enhancement can be realized from larger NGs substrates by optimizing their DL of nanostructures between the NGs. Based on simulation we could demonstrate that, by optimizing the DL, SERS enhancement from larger NG substrate such as 60 and 80 nm could be comparable to that of smaller (40nm NG substrates. We envision that this concept will open up new regime in the nanofabrication of practically feasible NG based plasmonic substrates with higher SERS enhancement. Initial results of our experiments are in close agreement with our simulated study.

  14. The physical activity climate in Minnesota middle and high schools.

    Science.gov (United States)

    Samuelson, Anne; Lytle, Leslie; Pasch, Keryn; Farbakhsh, Kian; Moe, Stacey; Sirard, John Ronald

    2010-11-01

    This article describes policies, practices, and facilities that form the physical activity climate in Minneapolis/St. Paul, Minnesota metro area middle and high schools and examines how the physical activity climate varies by school characteristics, including public/private, school location and grade level. Surveys examining school physical activity practices, policies and environment were administered to principals and physical education department heads from 115 middle and high schools participating in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and Activity (TREC-IDEA) study. While some supportive practices were highly prevalent in the schools studied (such as prohibiting substitution of other classes for physical education); other practices were less common (such as providing opportunity for intramural (noncompetitive) sports). Public schools vs. private schools and schools with a larger school enrollment were more likely to have a school climate supportive of physical activity. Although schools reported elements of positive physical activity climates, discrepancies exist by school characteristics. Of note, public schools were more than twice as likely as private schools to have supportive physical activity environments. Establishing more consistent physical activity expectations and funding at the state and national level is necessary to increase regular school physical activity.

  15. Paper based Flexible and Conformal SERS Substrate for Rapid Trace Detection on Real-world Surfaces

    Science.gov (United States)

    Singamaneni, Srikanth; Lee, Chang; Tian, Limei

    2011-03-01

    One of the important but often overlooked considerations in the design of surface enhanced Raman scattering (SERS) substrates for trace detection is the efficiency of sample collection. Conventional designs based on rigid substrates such as silicon, alumina, and glass resist conformal contact with the surface under investigation, making the sample collection inefficient. We demonstrate a novel SERS substrate based on common filter paper adsorbed with gold nanorods, which allows conformal contact with real-world surfaces, thus dramatically enhancing the sample collection efficiency compared to conventional rigid substrates. We demonstrate the detection of trace amounts of analyte (140 pg spread over 4 cm2) by simply swabbing the surface under investigation with the novel SERS substrate. The hierarchical fibrous structure of paper serves as a 3D vasculature for easy uptake and transport of the analytes to the electromagnetic hot spots in the paper. Simple yet highly efficient and cost effective SERS substrate demonstrated here brings SERS based trace detection closer to real-world applications. We acknowledge the financial support from Center for Materials Innovation at Washington University.

  16. PGC-1alpha Gly482Ser polymorphism associates with hypertension among Danish whites

    DEFF Research Database (Denmark)

    Andersen, Gitte; Wegner, Lise; Jensen, Dorit Packert

    2005-01-01

    in combination with previously published results. The Ser/Ser genotype was significantly associated with a reduced risk of hypertension and with lower systolic, diastolic, and mean arterial blood pressure levels, predominantly among women. Finally, in a combined analysis using data obtained in both sexes...... to elucidate the differential role of this polymorphism in men and women.......PGC-1alpha is a coactivator of numerous transcription factors and is expressed in tissues with high energy demands and abundant in mitochondria. It is induced in the myocardium on fasting and physical exercise, and cardiac-specific overexpression stimulates mitochondrial biogenesis in mice...

  17. SERS analysis of Ag nanostructures produced by ion-beam deposition

    Science.gov (United States)

    Atanasov, P. A.; Nedyalkov, N. N.; Nikov, Ru G.; Grüner, Ch; Rauschenbach, B.; Fukata, N.

    2018-03-01

    This study deals with the development of a novel technique for formation of advanced Ag nanostructures (NSs) to be applied to high-resolution analyses based on surface enhanced Raman scattering (SERS). It has direct bearing on human health and food quality, e.g., monitoring small amount or traces of pollutants or undesirable additives. Three types of nanostructured Ag samples were produced using ion-beam deposition at glancing angle (GLAD) on quartz. All fabricated structures were covered with BI-58 pesticide (dimethoate) or Rhodamine 6G (R6G) for testing their potential for use as substrates for (SERS).

  18. Nanostructured Silver Substrates With Stable and Universal SERS Properties: Application to Organic Molecules and Semiconductor Nanoparticles

    Directory of Open Access Journals (Sweden)

    Waurisch C

    2009-01-01

    Full Text Available Abstract Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60–80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time.

  19. Coupling FT Raman and FT SERS microscopy with TLC plates for in situ identification of chemical compounds

    Science.gov (United States)

    Caudin, J. P.; Beljebbar, A.; Sockalingum, G. D.; Angiboust, J. F.; Manfait, M.

    1995-11-01

    Direct analysis of sub-femtogram quantities of chemical compounds on thin layer chromatography plates has been made possible by associating Fourier transform Raman microspectroscopy with SERS spectroscopy. The interfacing elements of the FT Raman microscope system are discussed and optimised such that a lateral resolution on the micron scale is achieved in the sample plane. Micro-FT SERS results obtained from a model biological molecule indicate preservation of molecular conformation upon adsorption at the SERS active surface. With NIR radiation it is thus possible to analyse plates with or without fluorescence indicators.

  20. Severe energy deficit at high altitude inhibits skeletal muscle mTORC1-mediated anabolic signaling without increased ubiquitin proteasome activity.

    Science.gov (United States)

    Margolis, Lee M; Carbone, John W; Berryman, Claire E; Carrigan, Christopher T; Murphy, Nancy E; Ferrando, Arny A; Young, Andrew J; Pasiakos, Stefan M

    2018-06-07

    Muscle loss at high altitude (HA) is attributable to energy deficit and a potential dysregulation of anabolic signaling. Exercise and protein ingestion can attenuate the effects of energy deficit on muscle at sea level (SL). Whether these effects are observed when energy deficit occurs at HA is unknown. To address this, muscle obtained from lowlanders ( n = 8 males) at SL, acute HA (3 h, 4300 m), and chronic HA (21 d, -1766 kcal/d energy balance) before [baseline (Base)] and after 80 min of aerobic exercise followed by a 2-mile time trial [postexercise (Post)] and 3 h into recovery (Rec) after ingesting whey protein (25 g) were analyzed using standard molecular techniques. At SL, Post, and REC, p-mechanistic target of rapamycin (mTOR) Ser2448 , p-p70 ribosomal protein S6 kinase (p70S6K) Ser424/421 , and p-ribosomal protein S6 (rpS6) Ser235/236 were similar and higher ( P anabolic resistance that is exacerbated by energy deficit during acclimatization, with no change in proteolysis.-Margolis, L. M., Carbone, J. W., Berryman, C. E., Carrigan, C. T., Murphy, N. E., Ferrando, A. A., Young, A. J., Pasiakos, S. M. Severe energy deficit at high altitude inhibits skeletal muscle mTORC1-mediated anabolic signaling without increased ubiquitin proteasome activity.

  1. Immunological Response of Hiv-Infected Children to Highly Active ...

    African Journals Online (AJOL)

    BACKGROUND: The effectiveness of highly active antiretroviral therapy (HAART) in children has not been well studied specially in developing countries where the burden of HIV is high. This study was aimed to assess the immunologic response of HIV-infected children to HAART at Pediatric ART Clinic Gondar University ...

  2. Magnetic activity effect on equatorial spread-F under high and low solar activity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Subbarao, K S.V.; Somayajulu, V V; Krishna Murthy, B V

    1986-08-01

    The effect of magnetic activity on spread-F at two equatorial stations, Trivandrum and Huancayo, separated in longitude by about 150 deg, under high and low solar activity conditions has been investigated. Magnetic activity produces strong inhibition effect on spread-F at Huancayo compared to that at Trivandrum especially during high solar activity period. This results in a decrease of spread-F with solar activity at Huancayo in contrast to Trivandrum. These findings are explained in terms of F-region electrodynamics and Rayleigh-Taylor instability mechanism for spread-F.

  3. Planar SERS nanostructures with stochastic silver ring morphology for biosensor chips

    DEFF Research Database (Denmark)

    Semenova, Anna; Goodilin, Eugene; Brazhe, Nadezda

    2012-01-01

    Surface-enhanced Raman spectroscopy (SERS) of living cells has rapidly become a powerful trend in biomedical diagnostics. It is a common belief that highly ordered, artificially engineered substrates are the best future decision in this field. This paper, however, describes an alternative...

  4. Silver-gold core-shell nanoparticles containing methylene blue as SERS labels for probing and imaging of live cells

    International Nuclear Information System (INIS)

    Guo, X.; Guo, Z.; Jin, Y.; Liu, Z.; Zhang, W.; Huang, D.

    2012-01-01

    We report on silver-gold core-shell nanostructures that contain Methylene Blue (MB) at the gold/x96silver interface. They can be used as reporter molecules in surface-enhanced Raman scattering (SERS) labels. The labels are stable and have strong SERS activity. TEM imaging revealed that these nanoparticles display bright and dark stripe structures. In addition, these labels can act as probes that can be detected and imaged through the specific Raman signatures of the reporters. We show that such SERS probes can identify cellular structures due to enhanced Raman spectra of intrinsic cellular molecules measured in the local optical fields of the core-shell nanostructures. They also provide structural information on the cellular environment as demonstrated for these nanoparticles as new SERS-active and biocompatible substrates for imaging of live cells. (author)

  5. Historia de una coma. Gadamer y el sentido del ser

    OpenAIRE

    Vattimo, Gianni

    2005-01-01

    A partir de la doble posibilidad de traducir en las lenguas románicas la expresión gadameriana «Sein, das verstanden werden kann, ist Sprache» como «El ser, que puede ser comprendido, es lenguaje» o como «El ser que puede ser comprendido es lenguaje», se consideran las importantes repercusiones ontológicas que tendría una interpretación más moderada (y más habitual) de ese enunciado (la primera exhibida), o una lectura más radical y nihilista (la que aquí se defiende) del mismo (la ...

  6. Pro-106-Ser mutation and EPSPS overexpression acting together simultaneously in glyphosate-resistant goosegrass (Eleusine indica).

    Science.gov (United States)

    Gherekhloo, Javid; Fernández-Moreno, Pablo T; Alcántara-de la Cruz, Ricardo; Sánchez-González, Eduardo; Cruz-Hipolito, Hugo E; Domínguez-Valenzuela, José A; De Prado, Rafael

    2017-07-27

    Glyphosate has been used for more than 15 years for weed management in citrus groves in the Gulf of Mexico, at up to 3-4 applications per year. Goosegrass (Eleusine indica (L.) Gaertn.) control has sometimes failed. In this research, the mechanisms governing three goosegrass biotypes (Ein-Or from an orange grove, and Ein-Pl1 and Ein-Pl2 from Persian lime groves) with suspected resistance to glyphosate were characterized and compared to a susceptible biotype (Ein-S). Dose-response and shikimate accumulation assays confirmed resistance of the resistant (R) biotypes. There were no differences in glyphosate absorption, but the R biotypes retained up to 62-78% of the herbicide in the treated leaf at 96 h after treatment (HAT), in comparison to the Ein-S biotype (36%). The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity in the Ein-Or and Ein-S biotypes was over 100-fold lower than the Ein-Pl1 and Ein-Pl2 ones. The latter showed a high EPSPS-basal activity, a mutation at Pro-106-Ser position in the EPSPS gene, and EPSPS overexpression. The EPSPS basal and EPSPS overexpression were positively correlated. The R goosegrass biotypes displayed poor glyphosate translocation. Furthermore, this grassweed showed, for the first time, two mechanisms at the target-site level (Pro-106-Ser mutation + EPSPS overexpression) acting together simultaneously against glyphosate.

  7. Activation analysis of high pure quartz used as packing materials

    International Nuclear Information System (INIS)

    Luknitskij, V.A.; Morozov, B.A.

    1979-01-01

    A γ-spectrometric technique of neutron activation determination of microelements in quartz tubes used as a packing material for irradiation in reactors is reported. The analysis of 29 micro-admixtures in quartz tubes of USSR brands ''spectrtosil'' and ''KV'' was carried out. The γ-spectra of ''KV'' quartz irradiated by thermal and epithermal neutrons are presented. The activation by epithermal neutrons provides an activity gain for the nuclei whose resonance integral is high enough as compared to the activation cross-section with regard to thermal neutrons. The activation by epithermal neutrons permits additional determination of W, Cd, V, Th, Mn and Ni and provides for a substantial decrease in the activity of 24 Na, 42 K, 140 La, 46 Sc, 141 Ce, 51 Cr, and 59 Fe, which hinder the determination of the above-mentioned elements. The microelement composition of Soviet-made quartz varieties is compared to that of foreign-made quartz brands

  8. Au nanoparticle arrays with tunable particle gaps by template-assisted electroless deposition for high performance surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    Mu Cheng; Xu Dongsheng; Zhang Jianping

    2010-01-01

    Surface-enhanced Raman spectroscopy (SERS) with enormous enhancements has shown great potential in ultrasensitive detection technologies, but the fabrication of large-scale, controllable and reproducible substrates with high SERS activity is a major challenge. Here, we report the preparation of Au nanoparticle arrays for SERS-active substrates with tunable particle sizes and interparticle gaps, and the enhancement factor of the SERS signal obtained from 4-mercaptopyridine probe molecules was as high as 10 7 . The experimental data points show the increase of enhancement factor as a function of the ratio of diameter to interparticle gap, which can be explained by the averaged electromagnetic field enhancement model. Furthermore, we demonstrated that this type of substrate merits its high uniformity, high reproducibility and excellent long-term stability. As the fabrication protocol of such a SERS substrate is simple and inexpensive, this substrate may anticipate a wide range of applications in SERS-based sensors.

  9. Nonequilibrium Chemical Effects in Single-Molecule SERS Revealed by Ab Initio Molecular Dynamics Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Sean A.; Apra, Edoardo; Govind, Niranjan; Hess, Wayne P.; El-Khoury, Patrick Z.

    2017-02-03

    Recent developments in nanophotonics have paved the way for achieving significant advances in the realm of single molecule chemical detection, imaging, and dynamics. In particular, surface-enhanced Raman scattering (SERS) is a powerful analytical technique that is now routinely used to identify the chemical identity of single molecules. Understanding how nanoscale physical and chemical processes affect single molecule SERS spectra and selection rules is a challenging task, and is still actively debated. Herein, we explore underappreciated chemical phenomena in ultrasensitive SERS. We observe a fluctuating excited electronic state manifold, governed by the conformational dynamics of a molecule (4,4’-dimercaptostilbene, DMS) interacting with a metallic cluster (Ag20). This affects our simulated single molecule SERS spectra; the time trajectories of a molecule interacting with its unique local environment dictates the relative intensities of the observable Raman-active vibrational states. Ab initio molecular dynamics of a model Ag20-DMS system are used to illustrate both concepts in light of recent experimental results.

  10. 75 FR 81284 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Draft...

    Science.gov (United States)

    2010-12-27

    ... Frequency and Ultra High Frequency Active SONAR Technology; Draft Programmatic Environmental Assessment and... Programmatic Environmental Assessment (PEA) for the Nationwide Use of High Frequency (HF) and Ultra High... potential impacts of each alternative on the human and natural environments. DATES: Comments and related...

  11. A microfluidic dialysis device for complex biological mixture SERS analysis

    KAUST Repository

    Perozziello, Gerardo

    2015-08-01

    In this paper, we present a microfluidic device fabricated with a simple and inexpensive process allowing rapid filtering of peptides from a complex mixture. The polymer microfluidic device can be used for sample preparation in biological applications. The device is fabricated by micromilling and solvent assisted bonding, in which a microdialysis membrane (cut-off of 12-14 kDa) is sandwiched in between an upper and a bottom microfluidic chamber. An external frame connects the microfluidic device to external tubes, microvalves and syringe pumps. Bonding strength and interface sealing are pneumatically tested. Microfluidic protocols are also described by using the presented device to filter a sample composed of specific peptides (MW 1553.73 Da, at a concentration of 1.0 ng/μl) derived from the BRCA1 protein, a tumor-suppressor molecule which plays a pivotal role in the development of breast cancer, and albumin (MW 66.5 kDa, at a concentration of 35 μg/μl), the most represented protein in human plasma. The filtered samples coming out from the microfluidic device were subsequently deposited on a SERS (surface enhanced Raman scattering) substrate for further analysis by Raman spectroscopy. By using this approach, we were able to sort the small peptides from the bigger and highly concentrated protein albumin and to detect them by using a label-free technique at a resolution down to 1.0 ng/μl.

  12. SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

    Energy Technology Data Exchange (ETDEWEB)

    Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

    2009-05-06

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  13. N-tritioacetoxyphthalimide: A new high specific activity tritioacetylating reagent

    International Nuclear Information System (INIS)

    Saljoughian, M.; Morimoto, Hiromi; Than, Chit

    1996-01-01

    The authors' aim was to develop a nonvolatile, stable, and facile tritioacetylating reagent and to demonstrate its use on simple peptides. Accordingly, the authors made the synthesis of high specific activity N-(tritioacetoxy) derivatives of succinimide, phthalimide, and naphthalimide a major focus. As the preferred approach, N-(tritioacetoxy)phthalimide was prepared by radical dehalogenation of N-(iodoacetoxy)phthalimide using high specific activity tributyltin tritide. This tritiated acetylation reagent was characterized by 3 H and 1 H NMR spectroscopy and by radio-HPLC. Efficacy of the reagent was investigated by tritioacetylation of several peptides at their N-terminal amino group. 26 refs., 1 fig

  14. Development of cutting machine for disposal of highly activated equipments

    International Nuclear Information System (INIS)

    Iimura, Katumichi; Kitajima, Toshio; Hosokawa, Jinsaku; Abe, Shinichi; Takahashi, Kiyoshi; Ogawa, Mituhiro; Iwai, Takashi

    1994-01-01

    JMTR (Japan Materials Testing Reactor) Project has developed a cutting machine which can cut a highly activated in-pile tube under water and its performance and safety have been confirmed. This machine is for the purpose of cutting a multiplet structure pipe and made possible to cut it under water by adopting under-water discharge method. Furthermore, contamination of canal water and atmosphere is prevented by combining a filter with this machine. This report describes the outline and performance of the developed cutting machine and also results of cutting highly activated in-pile tubes. (author)

  15. Recommendations of activity restriction in high-risk pregnancy scenarios

    DEFF Research Database (Denmark)

    Bendix, Jane; Hegaard, Hanne Kristine; Bergholt, Thomas

    2015-01-01

    activity restriction more often than obstetricians in five of the nine scenarios, in women with preterm premature rupture of membranes, preterm labour, cervical ripening, total placenta praevia, and intrauterine growth restriction, whereas no differences were found in the remaining scenarios. Compared...... to the obstetricians, the midwives also reported that they expected the recommendation to be more effective. Most midwives and obstetricians reported that they thought strict activity restriction was associated with severe or moderate adverse effect, and recommended antithrombotic prophylaxis. Conclusions: Danish...... obstetricians and midwives prescribe activity restriction in most high-risk pregnancies. The degree of activity restriction and the presumed effect vary between clinicians. This may reflect different attitudes and lack of guidelines based on clinical studies of a possible benefit of activity restriction....

  16. Physical activity barriers and motivators among high-risk employees.

    Science.gov (United States)

    Paguntalan, John C; Gregoski, Mathew

    2016-11-22

    Worksite wellness programs offer an ideal setting to target high-risk sedentary workers to improve health status. Lack of physical activity is associated with increased risk for coronary heart disease and mortality. Despite the risks, the number of sedentary workers is increasing. This study examined the perceived barriers and motivators for physical activity among employees at high-risk for coronary heart disease. A purposive sample of 24 high-risk workers participating in a wellness program in rural South Carolina were enrolled in the study. Qualitative data was obtained through semi-structured face-to-face interviews. Grounded theory was used to analyze qualitative data, and identify overarching themes. Physical limitations due to pain and weakness, lack of motivation, and lack of time emerged as the main barriers to physical activity. Family relationships were reported as the strongest motivator along with social support and potential health benefits. Findings highlight the unique experience of high-risk workers with physical activity. The findingsunderscore the need to design and implement effective interventions specifically designed to meet the needs of high-risk employees.

  17. Dyslipidemia in HIV Infected Children Receiving Highly Active Antiretroviral Therapy.

    Science.gov (United States)

    Mandal, Anirban; Mukherjee, Aparna; Lakshmy, R; Kabra, Sushil K; Lodha, Rakesh

    2016-03-01

    To assess the prevalence of dyslipidemia and lipodystrophy in Indian children receiving non-nucleoside reverse transcriptase inhibitor (NNRTI) based highly active antiretroviral therapy (HAART) and to determine the associated risk factors for the same. The present cross-sectional study was conducted at a Pediatric Clinic of a tertiary care teaching center in India, from May 2011 through December 2012. HIV infected children aged 5-15 y were enrolled if they did not have any severe disease or hospital admission within last 3 mo or receive any medications known to affect the lipid profile. Eighty-one children were on highly active antiretroviral therapy (HAART) for at least 6 mo and 16 were receiving no antiretroviral therapy (ART). Participants' sociodemographic, nutritional, clinical, and laboratory data were recorded in addition to anthropometry and evidence of lipodystrophy. Fasting lipid profile, apolipoprotein A1 and B levels were done for all the children. Among the children on highly active antiretroviral therapy (HAART), 38.3 % had dyslipidemia and 80.2 % had lipodystrophy, while 25 % antiretroviral therapy (ART) naïve HIV infected children had dyslipidemia. No clinically significant risk factors could be identified that increased the risk of dyslipidemia or lipodystrophy in children on highly active antiretroviral therapy (HAART). There is a high prevalence of dyslipidemia and lipodystrophy in Indian children with HIV infection with an imminent need to establish facilities for testing and treatment of these children for metabolic abnormalities.

  18. Glutamate Counteracts Dopamine/PKA Signaling via Dephosphorylation of DARPP-32 Ser-97 and Alteration of Its Cytonuclear Distribution.

    Science.gov (United States)

    Nishi, Akinori; Matamales, Miriam; Musante, Veronica; Valjent, Emmanuel; Kuroiwa, Mahomi; Kitahara, Yosuke; Rebholz, Heike; Greengard, Paul; Girault, Jean-Antoine; Nairn, Angus C

    2017-01-27

    The interaction of glutamate and dopamine in the striatum is heavily dependent on signaling pathways that converge on the regulatory protein DARPP-32. The efficacy of dopamine/D1 receptor/PKA signaling is regulated by DARPP-32 phosphorylated at Thr-34 (the PKA site), a process that inhibits protein phosphatase 1 (PP1) and potentiates PKA action. Activation of dopamine/D1 receptor/PKA signaling also leads to dephosphorylation of DARPP-32 at Ser-97 (the CK2 site), leading to localization of phospho-Thr-34 DARPP-32 in the nucleus where it also inhibits PP1. In this study the role of glutamate in the regulation of DARPP-32 phosphorylation at four major sites was further investigated. Experiments using striatal slices revealed that glutamate decreased the phosphorylation states of DARPP-32 at Ser-97 as well as Thr-34, Thr-75, and Ser-130 by activating NMDA or AMPA receptors in both direct and indirect pathway striatal neurons. The effect of glutamate in decreasing Ser-97 phosphorylation was mediated by activation of PP2A. In vitro phosphatase assays indicated that the PP2A/PR72 heterotrimer complex was likely responsible for glutamate/Ca 2+ -regulated dephosphorylation of DARPP-32 at Ser-97. As a consequence of Ser-97 dephosphorylation, glutamate induced the nuclear localization in cultured striatal neurons of dephospho-Thr-34/dephospho-Ser-97 DARPP-32. It also reduced PKA-dependent DARPP-32 signaling in slices and in vivo Taken together, the results suggest that by inducing dephosphorylation of DARPP-32 at Ser-97 and altering its cytonuclear distribution, glutamate may counteract dopamine/D1 receptor/PKA signaling at multiple cellular levels. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Glutamate Counteracts Dopamine/PKA Signaling via Dephosphorylation of DARPP-32 Ser-97 and Alteration of Its Cytonuclear Distribution*

    Science.gov (United States)

    Nishi, Akinori; Matamales, Miriam; Musante, Veronica; Valjent, Emmanuel; Kuroiwa, Mahomi; Kitahara, Yosuke; Rebholz, Heike; Greengard, Paul; Girault, Jean-Antoine; Nairn, Angus C.

    2017-01-01

    The interaction of glutamate and dopamine in the striatum is heavily dependent on signaling pathways that converge on the regulatory protein DARPP-32. The efficacy of dopamine/D1 receptor/PKA signaling is regulated by DARPP-32 phosphorylated at Thr-34 (the PKA site), a process that inhibits protein phosphatase 1 (PP1) and potentiates PKA action. Activation of dopamine/D1 receptor/PKA signaling also leads to dephosphorylation of DARPP-32 at Ser-97 (the CK2 site), leading to localization of phospho-Thr-34 DARPP-32 in the nucleus where it also inhibits PP1. In this study the role of glutamate in the regulation of DARPP-32 phosphorylation at four major sites was further investigated. Experiments using striatal slices revealed that glutamate decreased the phosphorylation states of DARPP-32 at Ser-97 as well as Thr-34, Thr-75, and Ser-130 by activating NMDA or AMPA receptors in both direct and indirect pathway striatal neurons. The effect of glutamate in decreasing Ser-97 phosphorylation was mediated by activation of PP2A. In vitro phosphatase assays indicated that the PP2A/PR72 heterotrimer complex was likely responsible for glutamate/Ca2+-regulated dephosphorylation of DARPP-32 at Ser-97. As a consequence of Ser-97 dephosphorylation, glutamate induced the nuclear localization in cultured striatal neurons of dephospho-Thr-34/dephospho-Ser-97 DARPP-32. It also reduced PKA-dependent DARPP-32 signaling in slices and in vivo. Taken together, the results suggest that by inducing dephosphorylation of DARPP-32 at Ser-97 and altering its cytonuclear distribution, glutamate may counteract dopamine/D1 receptor/PKA signaling at multiple cellular levels. PMID:27998980

  20. Aloe vera Derived Activated High-Surface-Area Carbon for Flexible and High-Energy Supercapacitors.

    Science.gov (United States)

    Karnan, M; Subramani, K; Sudhan, N; Ilayaraja, N; Sathish, M

    2016-12-28

    Materials which possess high specific capacitance in device configuration with low cost are essential for viable application in supercapacitors. Herein, a flexible high-energy supercapacitor device was fabricated using porous activated high-surface-area carbon derived from aloe leaf (Aloe vera) as a precursor. The A. vera derived activated carbon showed mesoporous nature with high specific surface area of ∼1890 m 2 /g. A high specific capacitance of 410 and 306 F/g was achieved in three-electrode and symmetric two-electrode system configurations in aqueous electrolyte, respectively. The fabricated all-solid-state device showed a high specific capacitance of 244 F/g with an energy density of 8.6 Wh/kg. In an ionic liquid electrolyte, the fabricated device showed a high specific capacitance of 126 F/g and a wide potential window up to 3 V, which results in a high energy density of 40 Wh/kg. Furthermore, it was observed that the activation temperature has significant role in the electrochemical performance, as the activated sample at 700 °C showed best activity than the samples activated at 600 and 800 °C. The electron microscopic images (FE-SEM and HR-TEM) confirmed the formation of pores by the chemical activation. A fabricated supercapacitor device in ionic liquid with 3 V could power up a red LED for 30 min upon charging for 20s. Also, it is shown that the operation voltage and capacitance of flexible all-solid-state symmetric supercapacitors fabricated using aloe-derived activated carbon could be easily tuned by series and parallel combinations. The performance of fabricated supercapacitor devices using A. vera derived activated carbon in all-solid-state and ionic liquid indicates their viable applications in flexible devices and energy storage.

  1. Potential application of SERS for arsenic speciation in biological matrices.

    Science.gov (United States)

    Yang, Mingwei; Matulis, Shannon; Boise, Lawrence H; McGoron, Anthony J; Cai, Yong

    2017-08-01

    Speciation of arsenic is usually carried out using chromatography-based methods coupled with spectroscopic determination; however, the inevitable procedures involving sample preparation and separation could potentially alter the integrity of the arsenic metabolites present in biological samples. Surface-enhanced Raman spectroscopy (SERS) could be a promising alternative for providing a reliable arsenic analysis under the influence of a cellular matrix. A method for arsenic speciation using SERS in cellular matrix was developed in this study and four arsenicals were selected, including arsenite (As III ), arsenate (As V ), monomethylarsonic acid (MMA V ) and dimethylarsinic acid (DMA V ). Silver nanoparticles in the form of colliodal suspension with different surface charges, i.e., coated with citrate (AgNPs-Citrate) and spermine (AgNPs-Spermine) were employed as SERS substrates. Adsorption of arsenicals on nanoparticles in colloidal suspensions and the cellular matrix and the pH, size, and zeta potential of the colloidal suspensions were investigated for a better understanding of the SERS signal response of arsenicals in the colloidal suspensions or under the influence of cellular matrix. Arsenicals showed substantially different SERS responses in the two colloidal suspensions, mainly because of the distinct difference in the interaction between the arsenicals and the nanoparticles. Arsenic speciation in cell lysate could be successfully carried out in AgNPs-Spermine suspension, while AgNPs-Citrate could not yield significant SERS signals under the experimental conditions. This study proved that AgNPs-Spermine colloidal suspension could be a promising SERS substrate for studying arsenic metabolism in a biological matrix, reducing the bias caused by traditional techniques that involve sample extraction and pretreatment.

  2. [TLC-FT-SERS study on a pair of optic isomers in ephedra].

    Science.gov (United States)

    Wang, Yuan; Zhang, Jin-zhi; Ma, Xin-yong

    2004-11-01

    A new method for analyzing the ingredients of a pair of optic isomers in ephedra, nor-ephedrine and nor-pseudo-ephedrine, using hyphenated high-efficiency thin layer chromatography (TLC) and surface-enhanced Raman spectroscopy (SERS) techniques, is reported. The results show that the characteristic spectral bands of nor-ephedrine and nor-pseudo-ephedrine can be obtained from the TLC spot with 8 microg sample of about 2.0 mm in diameter. The difference between the SERS and solid spectra was found. Spectral bands at 1004 cm(-1) and 1605 cm(-1) were found greatly enhanced. Molecule was absorbed in surface silver sol by pi electrons in ring. Under similar experimental conditions the spectral information of Levo-nor-ephedrine ramifications TLC-SERS is rich with strong credibility, whereas dextral-nor-ephedrine ramifications show a relatively strong fluorescence backdrop with less spectral information and weak credibility. The effective combination of TLC and SERS can be used to analyse the chemical ingredients with high sensitivity.

  3. A highly sensitive nanoscale pH-sensor using Au nanoparticles linked by a multifunctional Raman-active reporter molecule.

    Science.gov (United States)

    Lawson, Latevi S; Chan, James W; Huser, Thomas

    2014-07-21

    Chemical sensing on the nanoscale has been breaking new ground since the discovery of surface enhanced Raman scattering (SERS). For nanoparticles, controlled particle aggregation is necessary to achieve the largest SERS enhancements. Therefore, aggregating agents such as salts or linker molecules are used in conjunction with chemically sensitive reporters in order to develop robust environmentally sensitive SERS probes. While salt-induced colloidal nanosphere aggregates have produced robust SERS signals, their variability in aggregate size contributes significantly to poor SERS signal reproducibility, which can complicate their use in in vitro cellular studies. Such systems often also lack reproducibility in spectral measurements between different nanoparticle clusters. Preaggregation of colloids via linkers followed by surface functionalization with reporter molecules results in the linker occupying valuable SERS hotspot volume which could otherwise be utilized by additional reporter molecules. Ideally, both functionalities should be obtained from a single molecule. Here, we report the use of 3,5-dimercaptobenzoic acid, a single multifunctional molecule that creates SERS hotspots via the controlled aggregation of nanoparticles, and also reports pH values. We show that 3,5-dimercaptobenzoic acid bound to Au nanospheres results in an excellent pH nanoprobe, producing very robust, and highly reproducible SERS signals that can report pH across the entire physiological range with excellent pH resolution. To demonstrate the efficacy of our novel pH reporters, these probes were also used to image both the particle and pH distribution in the cytoplasm of human induced pluripotent stem cells (hiPSCs).

  4. Sensory experience ratings (SERs) for 1,659 French words: Relationships with other psycholinguistic variables and visual word recognition.

    Science.gov (United States)

    Bonin, Patrick; Méot, Alain; Ferrand, Ludovic; Bugaïska, Aurélia

    2015-09-01

    We collected sensory experience ratings (SERs) for 1,659 French words in adults. Sensory experience for words is a recently introduced variable that corresponds to the degree to which words elicit sensory and perceptual experiences (Juhasz & Yap Behavior Research Methods, 45, 160-168, 2013; Juhasz, Yap, Dicke, Taylor, & Gullick Quarterly Journal of Experimental Psychology, 64, 1683-1691, 2011). The relationships of the sensory experience norms with other psycholinguistic variables (e.g., imageability and age of acquisition) were analyzed. We also investigated the degree to which SER predicted performance in visual word recognition tasks (lexical decision, word naming, and progressive demasking). The analyses indicated that SER reliably predicted response times in lexical decision, but not in word naming or progressive demasking. The findings are discussed in relation to the status of SER, the role of semantic code activation in visual word recognition, and the embodied view of cognition.

  5. Metal Nanoparticles Deposited on Porous Silicon Templates as Novel Substrates for SERS

    Directory of Open Access Journals (Sweden)

    Lara Mikac

    2015-12-01

    Full Text Available In this paper, results on preparation of stable and uniform SERS solid substrates using macroporous silicon (pSi with deposited silver and gold are presented. Macroporous silicon is produced by anodisation of p-type silicon in hydrofluoric acid. The as prepared pSi is then used as a template for Ag and Au depositions. The noble metals were deposited in three different ways: by immersion in silver nitrate solution, by drop-casting silver colloidal solution and by pulsed laser ablation (PLA. Substrates obtained by different deposition processes were evaluated for SERS efficiency using methylene blue (MB and rhodamine 6G (R6G at 514.5, 633 and 785 nm. Using 514.5 nm excitation and R6G the limits of detection (LOD for macroporous Si samples with noble metal nanostructures obtained by immersion of pSi sample in silver nitrate solution and by applying silver colloidal solution to pSi template were 10–9 M and 10–8 M respectively. Using 633 nm laser and MB the most noticeable SERS activity gave pSi samples ablated with 30000 and 45000 laser pulses where the LODs of 10–10 M were obtained. The detection limit of 10–10 M was also reached for 4 mA cm–2-15 min pSi sample, silver ablated with 30000 pulses. Macroporous silicon proved to be a good base for the preparation of SERS substrates.

  6. Synthesis of a tritiated herbicide with high activity: methyl thifensulfuron

    International Nuclear Information System (INIS)

    Bastide, J.; Ortega, F.

    1993-01-01

    In order to study the binding on acetolactate synthase, a tritiated herbicide sulfonylurea (thifensulfuron methyl) of high specific activity was synthesized. By use of C 3 H 3 I for esterification of an acid group, a rapid incorporation of tritium into this compound may be achieved. (Author)

  7. Correlates of highly active antiretroviral therapy adherence among ...

    African Journals Online (AJOL)

    Correlates of highly active antiretroviral therapy adherence among urban Ethiopian clients. ... clients' self-reported adherence to HAART medication, a descriptive, comparative cross-sectional study was carried out among adults receiving HAART medication at the Zewditu Memorial Hospital ART clinic in Addis Ababa.

  8. Roles of family dynamics on adherence to highly active antiretroviral ...

    African Journals Online (AJOL)

    Background: Adherence to highly active antiretroviral therapy (HAART) has been proven to be the only effective treatment for HIV/AIDS worldwide. Good adherence to HAART might require good family support. Objective: To determine the family dynamics and social support of people living with HIV/AIDS (PLWHA) and its ...

  9. Influence of highly active antiretroviral therapy (HAART) on the ...

    African Journals Online (AJOL)

    This report is part of the ongoing highly active antiretroviral therapy (HAART) trial, 167 patients were enlisted, but current analysis was restricted to 107 patients that were about a year old on the programme. The baseline weight, CD4+ cell count and serum albumin of 59 males and 48 females age 15-60 years, were ...

  10. Contact system activation and high thrombin generation in hyperthyroidism.

    Science.gov (United States)

    Kim, Namhee; Gu, Ja-Yoon; Yoo, Hyun Ju; Han, Se Eun; Kim, Young Il; Nam-Goong, Il Sung; Kim, Eun Sook; Kim, Hyun Kyung

    2017-05-01

    Hyperthyroidism is associated with increased thrombotic risk. As contact system activation through formation of neutrophil extracellular traps (NET) has emerged as an important trigger of thrombosis, we hypothesized that the contact system is activated along with active NET formation in hyperthyroidism and that their markers correlate with disease severity. In 61 patients with hyperthyroidism and 40 normal controls, the levels of coagulation factors (fibrinogen, and factor VII, VIII, IX, XI and XII), D-dimer, thrombin generation assay (TGA) markers, NET formation markers (histone-DNA complex, double-stranded DNA and neutrophil elastase) and contact system markers (activated factor XII (XIIa), high-molecular-weight kininogen (HMWK), prekallikrein and bradykinin) were measured. Patients with hyperthyroidism showed higher levels of fibrinogen (median (interquartile range), 315 (280-344) vs 262 (223-300), P  = 0.001), D-dimer (103.8 (64.8-151.5) vs 50.7 (37.4-76.0), P  hyperthyroidism's contribution to coagulation and contact system activation. Free T4 was significantly correlated with factors VIII and IX, D-dimer, double-stranded DNA and bradykinin. This study demonstrated that contact system activation and abundant NET formation occurred in the high thrombin generation state in hyperthyroidism and were correlated with free T4 level. © 2017 European Society of Endocrinology.

  11. Highly Crumpled All-Carbon Transistors for Brain Activity Recording.

    Science.gov (United States)

    Yang, Long; Zhao, Yan; Xu, Wenjing; Shi, Enzheng; Wei, Wenjing; Li, Xinming; Cao, Anyuan; Cao, Yanping; Fang, Ying

    2017-01-11

    Neural probes based on graphene field-effect transistors have been demonstrated. Yet, the minimum detectable signal of graphene transistor-based probes is inversely proportional to the square root of the active graphene area. This fundamentally limits the scaling of graphene transistor-based neural probes for improved spatial resolution in brain activity recording. Here, we address this challenge using highly crumpled all-carbon transistors formed by compressing down to 16% of its initial area. All-carbon transistors, chemically synthesized by seamless integration of graphene channels and hybrid graphene/carbon nanotube electrodes, maintained structural integrity and stable electronic properties under large mechanical deformation, whereas stress-induced cracking and junction failure occurred in conventional graphene/metal transistors. Flexible, highly crumpled all-carbon transistors were further verified for in vivo recording of brain activity in rats. These results highlight the importance of advanced material and device design concepts to make improvements in neuroelectronics.

  12. Enhancing SERS by Means of Supramolecular Charge Transfer

    Science.gov (United States)

    Wong, Eric; Flood, Amar; Morales, Alfredo

    2009-01-01

    In a proposed method of sensing small quantities of molecules of interest, surface enhanced Raman scattering (SERS) spectroscopy would be further enhanced by means of intermolecular or supramolecular charge transfer. There is a very large potential market for sensors based on this method for rapid detection of chemical and biological hazards. In SERS, the Raman signals (vibrational spectra) of target molecules become enhanced by factors of the order of 108 when those molecules are in the vicinities of nanostructured substrate surfaces that have been engineered to have plasmon resonances that enhance local electric fields. SERS, as reported in several prior NASA Tech Briefs articles and elsewhere, has remained a research tool and has not yet been developed into a practical technique for sensing of target molecules: this is because the short range (5 to 20 nm) of the field enhancement necessitates engineering of receptor molecules to attract target molecules to the nanostructured substrate surfaces and to enable reliable identification of the target molecules in the presence of interferants. Intermolecular charge-transfer complexes have been used in fluorescence-, photoluminescence-, and electrochemistry-based techniques for sensing target molecules, but, until now, have not been considered for use in SERS-based sensing. The basic idea of the proposed method is to engineer receptor molecules that would be attached to nanostructured SERS substrates and that would interact with the target molecules to form receptor-target supramolecular charge-transfer complexes wherein the charge transfer could be photoexcited.

  13. IAEA high temperature gas-cooled reactor activities

    International Nuclear Information System (INIS)

    Kendall, J.M.

    2000-01-01

    The IAEA activities on high temperature gas-cooled reactors are conducted with the review and support of the Member states, primarily through the International Working Group on Gas-Cooled Reactors (IWG-GCR). This paper summarises the results of the IAEA gas-cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (authors)

  14. Business cycle and innovation activity in medium-high and high technology industry in Poland

    Directory of Open Access Journals (Sweden)

    Dzikowski Piotr

    2015-12-01

    Full Text Available This article examines differences in an impact of business cycle phases on innovation activity in medium-high and high technology industry in Poland. It is assumed that each business cycle phase influences innovation activity in the same fashion, but its impact varies and it depends on the firm’s innovation activity. The higher innovation activity the less impact of business cycle. The scope of the survey relates to innovation in MHT and HT industry in Poland. The data concerns the innovation at the firm level and the diffusion “new for the company”. Innovation activity is defined by the following activities: (1 expenditure on research and development and investments in fixed assets not used so far such as: abuildings, premises and land; b machinery and equipment, c computer software; (2 implementation of new products and technological processes and (3 innovation cooperation. The methodological part of the analysis includes a logit modeling. The survey includes 1355 companies. Business cycle has a great influence on innovation activity in MTH and HT industry in Poland. The influence of recovery phase is positive whereas both stagnation and recession phases decrease the probability of innovation activity. The character of influence depends on the propensity to take innovation activity. The higher level of innovation activity the enterprises present the less influence of business cycle they get.

  15. Using Electrochemical SERS to Measure the Redox Potential of Drug Molecules Bound to dsDNA—a Study of Mitoxantrone

    International Nuclear Information System (INIS)

    Meneghello, Marta; Papadopoulou, Evanthia; Ugo, Paolo; Bartlett, Philip N.

    2016-01-01

    Interaction with DNA plays an important role in the biological activity of some anticancer drug molecules. In this paper we show that electrochemical surface enhanced Raman spectroscopy at sphere segment void gold electrodes can be used as a highly sensitive technique to measure the redox potential of the anticancer drug mitoxantrone bound to dsDNA. For this system we show that we can follow the redox reaction of the bound molecule and can extract the redox potential for the molecule bound to dsDNA by deconvolution of the SER spectra recorded as a function of electrode potential. We find that mitoxantrone bound to dsDNA undergoes a 2 electron, 1 proton reduction and that the redox potential (-0.87 V vs. Ag/AgCl at pH 7.2) is shifted approximately 0.12 V cathodic of the corresponding value at a glassy carbon electrode. Our results also show that the reduced form of mitoxantrone remains bound to dsDNA and we are able to use the deconvoluted SER spectra of the reduced mitoxantrone as a function of electrode potential to follow the electrochemically driven melting of the dsDNA at more negative potentials.

  16. Ser lugar e ser território como experiências do ser-no-mundo: um exercício de existencialismo geográfico

    Directory of Open Access Journals (Sweden)

    Angelo Serpa

    2017-10-01

    Full Text Available Este ensaio busca aprofundar uma abordagem existencialista dos conceitos de lugar e território assumindo o pressuposto de que eles remetem, antes de tudo, a experiências geográficas que ora se distinguem, ora se aproximam e carregam em si a marca do espaço vivido. Para esta análise, parte-se do conceito de geograficidade – a base pré-consciente e pré-conceitual da geografia – assumindo também que, antes de qualquer conceituação ou estratégia de representação conceitual, as pessoas são seres essencialmente espaciais e que viver é produzir/experienciar espaço. O ensaio está dividido em seis seções: a introdução, uma problematização da dialética entre interior e exterior e seu desdobramento numa abordagem de como lugar e território se exprimem como modos geográficos de existência no espaço público; nas duas últimas seções, reflete-se sobre o papel do corpo nos processos de apropriação do espaço e sobre como ser lugar e ser território se exprimem como facetas do ser-no-mundo em seu sentido mais político.

  17. A versatile SERS-based immunoassay for immunoglobulin detection using antigen-coated gold nanoparticles and malachite green-conjugated protein A/G

    Science.gov (United States)

    A surface enhanced Raman scattering (SERS) immunoassay for antibody detection in serum is described in the present work. The developed assay is conducted in solution and utilizes Au nanoparticles coated with the envelope (E) protein of West Nile Virus (WNV) as the SERS-active substrate and malachite...

  18. High repetition rate, high energy, actively Q-switched all-in-fiber laser

    Science.gov (United States)

    Lecourt, J. B.; Bertrand, A.; Guillemet, S.; Hernandez, Y.; Giannone, D.

    2010-05-01

    We report an actively Q-switched Ytterbium-doped all-in-fibre laser delivering 10ns pulses with high repetition rate (from 100kHz to 1MHz). The laser operation has been validated at three different wavelengths (1040, 1050 and 1064nm). The laser can deliver up to 20Watts average power with an high beam quality (M2 = 1).

  19. Physical properties of highly active liquor containing molybdate solids

    International Nuclear Information System (INIS)

    Dunnett, B.; Ward, T.; Roberts, R.; Cheeseright, J.

    2016-01-01

    The reprocessing of irradiated nuclear fuel at Sellafield produces a nitric acid based Highly Active Liquor (HAL) waste. The liquor, containing fission products and process additives, is concentrated in an evaporator in order to reduce the volume and is then stored in Highly Active Storage Tanks (HASTs) prior to vitrification. Caesium phosphomolybdate (CPM) is precipitated during the evaporation process and can convert to zirconium molybdate (ZM) during storage. During Post Operational Clean Out (POCO) of the HASTs, it is expected that their highly active content will be reduced by repeated cycles of washing using nitric acid and other reagents. Initial washings are likely to have a chemical composition comparable to concentrated HAL, becoming more dilute during the wash-out process. It is expected that the wash-out process will also recover significant quantities of molybdate solids (ZM, CPM or a mixture) from the HASTs. In order to determine the processing challenges from such washings during POCO, the physical properties of varying concentrations of non-active HAL simulants containing molybdate solids have recently been measured by the UK's National Nuclear Laboratory. The following measurements are presented and discussed: Particle size distribution; Density; Settling behaviour of solids; Voidage of settled sediment beds; Viscosity; Yield stress; And influence of ZM morphology on physical properties. (authors)

  20. Characterization of active CMOS pixel sensors on high resistive substrate

    Energy Technology Data Exchange (ETDEWEB)

    Hirono, Toko; Hemperek, Tomasz; Huegging, Fabian; Krueger, Hans; Rymaszewski, Piotr; Wermes, Norbert [Physikalisches Institut, Universitaet Bonn, Bonn (Germany)

    2016-07-01

    Active CMOS pixel sensors are very attractive as radiation imaging pixel detector because they do not need cost-intensive fine pitch bump bonding. High radiation tolerance and time resolution are required to apply those sensors to upcoming particle physics experiments. To achieve these requirements, the active CMOS pixel sensors were developed on high resistive substrates. Signal charges are collected faster by drift in high resistive substrates than in standard low resistive substrates yielding also a higher radiation tolerance. A prototype of the active CMOS pixel sensor has been fabricated in the LFoundry 150 nm CMOS process on 2 kΩcm substrate. This prototype chip was thinned down to 300 μm and the backside has been processed and can contacted by an aluminum contact. The breakdown voltage is around -115 V, and the depletion width has been measured to be as large as 180 μm at a bias voltage of -110 V. Gain and noise of the readout circuitry agree with the designed values. Performance tests in the lab and test beam have been done before and after irradiation with X-rays and neutrons. In this presentation, the measurement results of the active CMOS prototype sensors are shown.

  1. Physical properties of highly active liquor containing molybdate solids

    Energy Technology Data Exchange (ETDEWEB)

    Dunnett, B.; Ward, T.; Roberts, R. [National Nuclear Laboratory, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom); Cheeseright, J. [Sellafield Ltd, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom)

    2016-07-01

    The reprocessing of irradiated nuclear fuel at Sellafield produces a nitric acid based Highly Active Liquor (HAL) waste. The liquor, containing fission products and process additives, is concentrated in an evaporator in order to reduce the volume and is then stored in Highly Active Storage Tanks (HASTs) prior to vitrification. Caesium phosphomolybdate (CPM) is precipitated during the evaporation process and can convert to zirconium molybdate (ZM) during storage. During Post Operational Clean Out (POCO) of the HASTs, it is expected that their highly active content will be reduced by repeated cycles of washing using nitric acid and other reagents. Initial washings are likely to have a chemical composition comparable to concentrated HAL, becoming more dilute during the wash-out process. It is expected that the wash-out process will also recover significant quantities of molybdate solids (ZM, CPM or a mixture) from the HASTs. In order to determine the processing challenges from such washings during POCO, the physical properties of varying concentrations of non-active HAL simulants containing molybdate solids have recently been measured by the UK's National Nuclear Laboratory. The following measurements are presented and discussed: Particle size distribution; Density; Settling behaviour of solids; Voidage of settled sediment beds; Viscosity; Yield stress; And influence of ZM morphology on physical properties. (authors)

  2. Beta activity measurements in high, variable gamma backgrounds

    International Nuclear Information System (INIS)

    Stanga, D.; Sandu, E.; Craciun, L.

    1997-01-01

    In many cases beta activity measurements must be performed in high and variable gamma backgrounds. In such instances it is necessary to use well-shielded detectors but this technique is limited to laboratory equipment and frequently insufficient. In order to perform in a simple manner beta activity measurements in high and variable backgrounds a software-aided counting technique have been developed and a counting system have been constructed. This technique combines the different counting techniques with traditional method of successive measurement of the sample and background. The counting system is based on a programmable multi-scaler which is endowed with appropriate software and allow all operations to be performed via keyboard in an interactive fashion. Two large - area proportional detectors were selected in order to have the same background and the same gamma response within 5%. A program has been developed for the counting data analysis and beta activity computing. The software-aided counting technique has been implemented for beta activity measurement in high and variable backgrounds. (authors)

  3. Label-free direct surface-enhanced Raman scattering (SERS) of nucleic acids (Conference Presentation)

    Science.gov (United States)

    Guerrini, Luca; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Xie, Hainan; Alvarez-Puebla, Ramon

    2016-03-01

    Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity. To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.

  4. Using Ag-embedded TiO{sub 2} nanotubes array as recyclable SERS substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [Lab of Advanced Materials, School of Materials Science & Engineering, Tsinghua University, Beijing 100084 (China); Zhuo, Yuqing; Huang, Liang [Lab of Advanced Materials, School of Materials Science & Engineering, Tsinghua University, Beijing 100084 (China); Mao, Duolu [School of Physical and Electronic Information Engineering, Qinghai Nationalities University, Xining, Qinghai 810007 (China)

    2016-12-01

    Highlights: • Ag embedded nanoparticles inside nanotube have better SERS enhancement than surface cap. • Ag NPs reconstruction via self-migration with UV and humidity control. • Self-cleaning effects both on organic molecule photo-oxidation as well as Ag ions photo-reduction. - Abstract: A simple strategy for synthesizing Ag-loaded TiO{sub 2} nanotube film for use as multifunctional photocatalyst and recyclable surface-enhanced Raman scattering (SERS) substrate is introduced. Highly aligned TiO{sub 2} nanotube arrays (TNTA) prepared via electrochemical anodization were used as a 3D rough host for silver nanoparticles. Ag deposits were sputtered in a vacuum, and it was found that their morphologies were mainly influenced by the diameters of nanotubes and the UV irradiation induced aging process, especially the self-migration of silver along the tubular wall. SERS and the self-cleaning effect were observed using Rhodamine 6G (R6G) as the probe molecule. The results showed that narrow nanotube and silver nanoparticles embedment contributed significantly to both the phenomenal SERS and recyclability.

  5. Nanostructured surfaces for analysis of anticancer drug and cell diagnosis based on electrochemical and SERS tools

    Science.gov (United States)

    El-Said, Waleed A.; Yoon, Jinho; Choi, Jeong-Woo

    2018-04-01

    Discovering new anticancer drugs and screening their efficacy requires a huge amount of resources and time-consuming processes. The development of fast, sensitive, and nondestructive methods for the in vitro and in vivo detection of anticancer drugs' effects and action mechanisms have been done to reduce the time and resources required to discover new anticancer drugs. For the in vitro and in vivo detection of the efficiency, distribution, and action mechanism of anticancer drugs, the applications of electrochemical techniques such as electrochemical cell chips and optical techniques such as surface-enhanced Raman spectroscopy (SERS) have been developed based on the nanostructured surface. Research focused on electrochemical cell chips and the SERS technique have been reviewed here; electrochemical cell chips based on nanostructured surfaces have been developed for the in vitro detection of cell viability and the evaluation of the effects of anticancer drugs, which showed the high capability to evaluate the cytotoxic effects of several chemicals at low concentrations. SERS technique based on the nanostructured surface have been used as label-free, simple, and nondestructive techniques for the in vitro and in vivo monitoring of the distribution, mechanism, and metabolism of different anticancer drugs at the cellular level. The use of electrochemical cell chips and the SERS technique based on the nanostructured surface should be good tools to detect the effects and action mechanisms of anticancer drugs.

  6. Using a silver-enhanced microarray sandwich structure to improve SERS sensitivity for protein detection.

    Science.gov (United States)

    Gu, Xuefang; Yan, Yuerong; Jiang, Guoqing; Adkins, Jason; Shi, Jian; Jiang, Guomin; Tian, Shu

    2014-03-01

    A simple and sensitive method, based on surface-enhanced Raman scattering (SERS), for immunoassay and label-free protein detection is reported. A series of bowl-shaped silver cavity arrays were fabricated by electrodeposition using a self-assembled polystyrene spheres template. The reflection spectra of these cavity arrays were recorded as a function of film thickness, and then correlated with SERS enhancement using sodium thiophenolate as the probe molecule. The results reveal that SERS enhancement can be maximized when the frequency of both the incident laser and the Raman scattering approach the frequency of the localized surface plasmon resonance. The optimized array was then used as the bottom layer of a silver nanoparticle-protein-bowl-shaped silver cavity array sandwich. The second layer of silver was introduced by the interactions between the proteins in the middle layer of the sandwich architecture and silver nanoparticles. Human IgG bound to the surface of this microcavity array can retain its recognition function. With the Raman reporter molecules labeled on the antibody, a detection limit down to 0.1 ng mL(-1) for human IgG is easily achieved. Furthermore, the SERS spectra of label-free proteins (catalase, cytochrome C, avidin and lysozyme) from the assembled sandwich have excellent reproducibility and high quality. The results reveal that the proposed approach has potential for use in qualitative and quantitative detection of biomolecules.

  7. SER Y ESTAR CON ADJETIVOS – SIGNIFICACION DE LAS PROPOSICIONES SER Y ESTAR CON ADJETIVOS – SIGNIFICACION DE LAS PROPOSICIONES

    Directory of Open Access Journals (Sweden)

    Javier García de María

    2008-07-01

    Full Text Available Ser y estar: uno de los temas difíciles de la enseñanza/aprendizaje del español. Este trabajo expone un enfoque que recurre a la significación como hilo conductor. Por una parte, a la significación de ser y de estar como verbos, en sí mismos. Por otra, a la significación de los adjetivos. El planteamiento no es ya qué significa un determinado adjetivo con ser o con estar, sino cuál de estos verbos puede expresar su significado único o cada uno de sus significados. Sobre esta base el análisis considera, primero, los significados de ser/estar y los significados de un adjetivo dado y, segundo, los resultados significativos que arroja la relación entre verbos y adjetivo. Cuando el significado de un adjetivo se pueda expresar con los dos verbos, la elección vendrá determinada por la intencionalidad del hablante en el contexto comunicativo en que se encuentre. A partir de aquí las construcciones en las que aparecen ser y estar son tratadas como proposiciones retórico-argumentativas.Ser and estar: a difficult aspect of Spanish as a foreign language. This essay presents an approach that takes signification as guide line. On the one hand, the signification of ser and estar for their own cause; on the other hand the signification of the adjectives. The question is no longer what the meaning of a given adjective is with ser or with estar, but with which of the two verbs is it possible to express the unique meaning or each of the meanings of that adjective. Starting from this basis the approach considers first, the isolated meanings of the verbs and of the adjectives and, second, the resultant signification out of the relation between the two sides. If the meaning of a given adjective can be expressed by both verbs, the selection of the verb is determined by the intentionality of the speaker in the communicative context in which he negotiates. From this background on the syntactical constructions in which ser and estar appear are treated as

  8. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  9. LA GENÉTICA Y LA DIGNIDAD DEL SER HUMANO

    OpenAIRE

    Nicolás Jouve de Barreda

    2013-01-01

    Los elementos biológicos del hombre no son suficientes para afrontar las cuestiones bioéticas que se plantean en torno al concepto de persona, pero son necesarios para definir con precisión las propiedades de los seres humanos y los aspectos teológicos, filosóficos y jurídicos que son atribuibles a cada persona. El ser humano es un ser singular. En él que conviven dos dimensiones de distinta naturaleza, una material y otra espiritual, y precisamente esta es la principal de las diferencias en...

  10. SERS Raman Sensor Based on Diameter-Modulated Sapphire Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Shimoji, Yutaka

    2010-08-09

    Surface enhanced Raman scattering (SERS) has been observed using a sapphire fiber coated with gold nano-islands for the first time. The effect was found to be much weaker than what was observed with a similar fiber coated with silver nanoparticles. Diameter-modulated sapphire fibers have been successfully fabricated on a laser heated pedestal growth system. Such fibers have been found to give a modest increase in the collection efficiency of induced emission. However, the slow response of the SERS effect makes it unsuitable for process control applications.

  11. High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation

    DEFF Research Database (Denmark)

    Lin, Lin; Pribenszky, Csaba; Molnár, Miklós

    2010-01-01

    An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...... by HHP treatment was investigated in different holding media with or without Ca(2+). The efficiency of activation was tested at different pressure levels and media including T2 (HEPES-buffered TCM-199 containing 2% cattle serum), and mannitol-PVA fusion medium with (MPVA + Ca(2+)) or without Ca(2...

  12. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles

    Science.gov (United States)

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  13. Fabrication of chitosan-silver nanoparticle hybrid 3D porous structure as a SERS substrate for biomedical applications

    Science.gov (United States)

    Jung, Gyeong-Bok; Kim, Ji-Hye; Burm, Jin Sik; Park, Hun-Kuk

    2013-05-01

    We propose a simple, low-cost, large-area, and functional surface enhanced Raman scattering (SERS) substrate for biomedical applications. The SERS substrate with chitosan-silver nanoparticles (chitosan-Ag NPs) hybrid 3D porous structure was fabricated simply by a one-step method. The chitosan was used as a template for the Ag NPs deposition. SERS enhancement by the chitosan-Ag NPs substrate was experimentally verified using rhodamine B as an analyte. Thiolated single stranded DNA was also measured for atopic dermatitis genetic markers (chemokines CCL17) at a low concentration of 5 pM. We successfully designed a novel SERS substrate with silver nanoparticle hybridized 3D porous chitosan that has the potential to become a highly sensitive and selective tool for biomedical applications.

  14. Next-generation Surface Enhanced Raman Scattering (SERS) Substrates for Hazard Detection

    Science.gov (United States)

    2012-09-01

    substrates at differing concentrations ranging from 0.05 ug/cm2 to 50 ug/cm2. These concentrations were independently validated by UV -Vis...standard Klarite substrates at a concentration of 5.0 ug/cm2. The concentration jetted was validated using a secondary UV -Vis technique.(20, 81) After... Spectros ., 994 (1997). [58] Alexander, T.A., Le, D.M., "Characterization of a commercialized SERS-active substrate and its application to the

  15. The Staphylococcus aureus autoinducer-2 synthase LuxS is regulated by Ser/Thr phosphorylation.

    Science.gov (United States)

    Cluzel, Marie-Eve; Zanella-Cléon, Isabelle; Cozzone, Alain J; Fütterer, Klaus; Duclos, Bertrand; Molle, Virginie

    2010-12-01

    The Staphylococcus aureus autoinducer-2 (AI-2) producer protein LuxS is phosphorylated by the Ser/Thr kinase Stk1 at a unique position, Thr14. The enzymatic activity of the phosphorylated isoform of LuxS was abrogated compared to that of nonphosphorylated LuxS, thus providing the first evidence of an AI-2-producing enzyme regulated by phosphorylation and demonstrating that S. aureus possesses an original and specific system for controlling AI-2 synthesis.

  16. The Staphylococcus aureus Autoinducer-2 Synthase LuxS Is Regulated by Ser/Thr Phosphorylation▿

    Science.gov (United States)

    Cluzel, Marie-Eve; Zanella-Cléon, Isabelle; Cozzone, Alain J.; Fütterer, Klaus; Duclos, Bertrand; Molle, Virginie

    2010-01-01

    The Staphylococcus aureus autoinducer-2 (AI-2) producer protein LuxS is phosphorylated by the Ser/Thr kinase Stk1 at a unique position, Thr14. The enzymatic activity of the phosphorylated isoform of LuxS was abrogated compared to that of nonphosphorylated LuxS, thus providing the first evidence of an AI-2-producing enzyme regulated by phosphorylation and demonstrating that S. aureus possesses an original and specific system for controlling AI-2 synthesis. PMID:20870760

  17. Positive selection at codon 38 of the human KCNE1 (= minK gene and sporadic absence of 38Ser-coding mRNAs in Gly38Ser heterozygotes

    Directory of Open Access Journals (Sweden)

    Pfeufer Arne

    2009-08-01

    Full Text Available Abstract Background KCNE1 represents the regulatory beta-subunit of the slowly activating delayed rectifier potassium channel (IKs. Variants of KCNE1 have repeatedly been linked to the long-QT syndrome (LQTS, a disorder which predisposes to deafness, ventricular tachyarrhythmia, syncope, and sudden cardiac death. Results We here analyze the evolution of the common Gly38Ser variant (rs1805127, using genomic DNAs, complementary DNAs, and HEK293-expressed variants of altogether 19 mammalian species. The between species comparison reveals that the human-specific Gly38Ser polymorphism evolved under strong positive Darwinian selection, probably in adaptation to specific challenges in the fine-tuning of IKs channels. The involved amino acid exchanges (Asp > Gly, Gly > Ser are moderately radical and do not induce apparent changes in posttranslational modification. According to population genetic analyses (HapMap phase II a heterozygote advantage accounts for the maintenance of the Gly38Ser polymorphism in humans. On the other hand, the expression of the 38Ser allele seems to be disadvantageous under certain conditions, as suggested by the sporadic deficiency of 38Ser-coding mRNAs in heterozygote Central Europeans and the depletion of homozygotes 38Ser in the Yoruban sample. Conclusion We speculate that individual differences in genomic imprinting or genomic recoding might have contributed to conflicting results of recent association studies between Gly38Ser polymorphism and QT phenotype. The findings thus highlight the relevance of mRNA data in future association studies of genotypes and clinical disorders. To the best of our knowledge, they moreover provide first time evidence for a unique pattern; i.e. coincidence of positive Darwinian selection and polymorphism with a sporadically suppressed expression of one allele.

  18. Preparation of sensitive and recyclable porous Ag/TiO{sub 2} composite films for SERS detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe, E-mail: thwang56@126.com

    2015-12-30

    Graphical abstract: - Highlights: • A new but simple method of fabricating robust TiO{sub 2} films on glass. • AgNPs were deposited on the surface of TiO{sub 2} films with the assistance of UV irradiation. • Substrates with high SERS sensitivity and excellent recyclability. - Abstract: Porous Ag/TiO{sub 2} composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO{sub 2} films. The highest SERS sensitivity that allowed as low as 10{sup −10} M aqueous CV to be detected, was achieved with the PEG/(C{sub 4}H{sub 9}O){sub 4}Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10{sup −10} to 10{sup −5} M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO{sub 2} film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  19. Parallel Computing:. Some Activities in High Energy Physics

    Science.gov (United States)

    Willers, Ian

    This paper examines some activities in High Energy Physics that utilise parallel computing. The topic includes all computing from the proposed SIMD front end detectors, the farming applications, high-powered RISC processors and the large machines in the computer centers. We start by looking at the motivation behind using parallelism for general purpose computing. The developments around farming are then described from its simplest form to the more complex system in Fermilab. Finally, there is a list of some developments that are happening close to the experiments.

  20. Synthesis of high specific activity tritium labelled compounds

    International Nuclear Information System (INIS)

    Parent, P.

    1986-01-01

    Tritiated methyl iodide of high specific activity is synthetized by Fischer-Tropsch reaction of tritium with carbon monoxide, tritiated methanol obtained is reacted with hydriodic acid. It is used for the synthesis of S-adenosyl L-methionine 3 H-methyl and of diazepam 3 H-methyl derivatives. Synthesis of 3-PPP 3 H: (hydroxy-3 phenyl)-3N-n propyl [ 3 H-2.3] piperidine [ 3 H-2.3] with a specific activity of 4.25 T Bq/mM (115 Ci/mM) and of baclofene 3 H with a specific activity of 0.925 TBq (25 Ci/mM) are also described [fr

  1. Characterizing electrostatic turbulence in tokamak plasmas with high MHD activity

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes-Filho, Z O; Santos Lima, G Z dos; Caldas, I L; Nascimento, I C; Kuznetsov, Yu K [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66316, 05315-970, Sao Paulo, SP (Brazil); Viana, R L, E-mail: viana@fisica.ufpr.b [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, 81531-990, Curitiba, PR (Brazil)

    2010-09-01

    One of the challenges in obtaining long lasting magnetic confinement of fusion plasmas in tokamaks is to control electrostatic turbulence near the vessel wall. A necessary step towards achieving this goal is to characterize the turbulence level and so as to quantify its effect on the transport of energy and particles of the plasma. In this paper we present experimental results on the characterization of electrostatic turbulence in Tokamak Chauffage Alfven Bresilien (TCABR), operating in the Institute of Physics of University of Sao Paulo, Brazil. In particular, we investigate the effect of certain magnetic field fluctuations, due to magnetohydrodynamical (MHD) instabilities activity, on the spectral properties of electrostatic turbulence at plasma edge. In some TCABR discharges we observe that this MHD activity may increase spontaneously, following changes in the edge safety factor, or after changes in the radial electric field achieved by electrode biasing. During the high MHD activity, the magnetic oscillations and the plasma edge electrostatic turbulence present several common linear spectral features with a noticeable dominant peak in the same frequency. In this article, dynamical analyses were applied to find other alterations on turbulence characteristics due to the MHD activity and turbulence enhancement. A recurrence quantification analysis shows that the turbulence determinism radial profile is substantially changed, becoming more radially uniform, during the high MHD activity. Moreover, the bicoherence spectra of these two kinds of fluctuations are similar and present high bicoherence levels associated with the MHD frequency. In contrast with the bicoherence spectral changes, that are radially localized at the plasma edge, the turbulence recurrence is broadly altered at the plasma edge and the scrape-off layer.

  2. Designing a new highly active liquid evaporator - 16075

    International Nuclear Information System (INIS)

    Robson, Paul; Candy, Emma

    2009-01-01

    The Highly Active Liquid Effluent Storage (HALES) plant stores, concentrates and conditions Highly Active Liquor (HAL) in evaporators for buffer storage in Highly Active Storage Tanks (HAST). Highly Active (HA) evaporators play a pivotal role in the delivery of reprocessing, historic clean up and hazard reduction missions across the Sellafield site. In addition to the engineering projects implemented to extend the life expectation of the current evaporator fleet, the UK Nuclear Decommissioning Agency (NDA) is sponsoring the construction of a new HA evaporator (Evaporator D) on the Sellafield site. The design and operation of the new HA evaporator is based on existing/recent HA evaporator technology but learning from past operational experience. Operational experience has been a key area where the existing plant operators have influenced both the new design itself and the requirements for commissioning and training. Many of the learning experiences require relatively simple engineering design modifications such as a new internal washing provision and transfer line blockage recovery systems, they are never-the-less expected to significantly improve the flexibility and operational capability of the new evaporator. Issues that the project delivery team has addressed as part of the development of the design and construction have included: - Minimising interruptions and/or changes to the normal operations of interfacing plants during construction, commissioning and operation of the new facility. - Modularization of the plant, enabling fabrication of the majority of the plant equipment off-site within a workshop (as opposed to on-site) environment improving Quality Assurance and reducing on-Site testing needs. - Drawing out the balance between operational and corrosion resistance improvements with actual design and delivery needs. - Provision of a new facility reliant on the infrastructure of an existing and ageing facility and the competing demands of the related safety

  3. Accelerator Production and Separations for High Specific Activity Rhenium-186

    Energy Technology Data Exchange (ETDEWEB)

    Jurisson, Silvia S. [Univ. of Missouri, Columbia, MO (United States); Wilbur, D. Scott [Univ. of Washington, Seattle, WA (United States)

    2016-04-01

    Tungsten and osmium targets were evaluated for the production of high specific activity rhenium-186. Rhenium-186 has potential applications in radiotherapy for the treatment of a variety of diseases, including targeting with monoclonal antibodies and peptides. Methods were evaluated using tungsten metal, tungsten dioxide, tungsten disulfide and osmium disulfide. Separation of the rhenium-186 produced and recycling of the enriched tungsten-186 and osmium-189 enriched targets were developed.

  4. Mining Chemical Activity Status from High-Throughput Screening Assays

    KAUST Repository

    Soufan, Othman

    2015-12-14

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare.

  5. Mining Chemical Activity Status from High-Throughput Screening Assays

    KAUST Repository

    Soufan, Othman; Ba Alawi, Wail; Afeef, Moataz A.; Essack, Magbubah; Rodionov, Valentin; Kalnis, Panos; Bajic, Vladimir B.

    2015-01-01

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare.

  6. Role of ser-237 in the substrate specificity of the carbapenem-hydrolyzing class A beta-lactamase Sme-1.

    Science.gov (United States)

    Sougakoff, W; Naas, T; Nordmann, P; Collatz, E; Jarlier, V

    1999-08-17

    The role of the serine residue found at position 237 in the carbapenemase Sme-1 has been investigated by constructing a mutant in which Ser-237 was replaced by an alanine. The S237A mutant showed a catalytic behavior against penicillins and aztreonam very similar to that of Sme-1. By contrast, S237A was characterized by a reduced catalytic efficiency against cephems, such as cephalothin and cephaloridine. In addition, the weak activity of Sme-1 against the cephamycin cefoxitin was hardly detectable with the mutant enzyme. Finally, the Ser-237-->Ala mutation resulted in a marked decrease in catalytic activity against imipenem, showing that Ser-237 contributes to the carbapenemase activity of the class A beta-lactamase Sme-1.

  7. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    International Nuclear Information System (INIS)

    Yoshinaka, Taeko; Yano, Keiji; Yamaguchi, Hikoyuki

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showed relatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells. (Kako, I.)

  8. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaka, T; Yano, K; Yamaguchi, H [Tokyo Univ. (Japan). Faculty of Agriculture

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showedrelatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells.

  9. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst

    KAUST Repository

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Jaroniec, Mietek; Qiao, Shi Zhang

    2016-01-01

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  10. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst.

    Science.gov (United States)

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-12-14

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  11. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst

    KAUST Repository

    Zheng, Yao

    2016-11-28

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  12. Visualization of elongation measurements using an SER universal testing platform

    Czech Academy of Sciences Publication Activity Database

    Pivokonský, Radek; Filip, Petr; Zelenková, Jana

    2015-01-01

    Roč. 25, č. 1 (2015), s. 1-8 ISSN 1430-6395 R&D Projects: GA ČR(CZ) GAP105/11/2342 Institutional support: RVO:67985874 Keywords : elongational viscosity * Universal Testing Platform (SER) * polymer melts * LDPE Subject RIV: BK - Fluid Dynamics Impact factor: 1.241, year: 2015

  13. SERS internship fall 1995 abstracts and research papers

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Beverly

    1996-05-01

    This report is a compilation of twenty abstracts and their corresponding full papers of research projects done under the US Department of Energy Science and Engineering Research Semester (SERS) program. Papers cover a broad range of topics, for example, environmental transport, supercomputers, databases, biology. Selected papers were indexed separately for inclusion the the Energy Science and Technology Database.

  14. BACH1 Ser919Pro variant and breast cancer risk

    Directory of Open Access Journals (Sweden)

    Eerola Hannaleena

    2006-01-01

    Full Text Available Abstract Background BACH1 (BRCA1-associated C-terminal helicase 1; also known as BRCA1-interacting protein 1, BRIP1 is a helicase protein that interacts in vivo with BRCA1, the protein product of one of the major genes for hereditary predisposition to breast cancer. Previously, two BACH1 germ line missense mutations have been identified in early-onset breast cancer patients with and without family history of breast and ovarian cancer. In this study, we aimed to evaluate whether there are BACH1 genetic variants that contribute to breast cancer risk in Finland. Methods The BACH1 gene was screened for germ line alterations among probands from 43 Finnish BRCA1/2 negative breast cancer families. Recently, one of the observed common variants, Ser-allele of the Ser919Pro polymorphism, was suggested to associate with an increased breast cancer risk, and was here evaluated in an independent, large series of 888 unselected breast cancer patients and in 736 healthy controls. Results Six BACH1 germ line alterations were observed in the mutation analysis, but none of these were found to associate with the cancer phenotype. The Val193Ile variant that was seen in only one family was further screened in an independent series of 346 familial breast cancer cases and 183 healthy controls, but no additional carriers were observed. Individuals with the BACH1 Ser919-allele were not found to have an increased breast cancer risk when the Pro/Ser heterozygotes (OR 0.90; 95% CI 0.70–1.16; p = 0.427 or Ser/Ser homozygotes (OR 1.02; 95% CI 0.76–1.35; p = 0.91 were compared to Pro/Pro homozygotes, and there was no association of the variant with any breast tumor characteristics, age at cancer diagnosis, family history of cancer, or survival. Conclusion Our results suggest that the BACH1 Ser919 is not a breast cancer predisposition allele in the Finnish study population. Together with previous studies, our results also indicate that although some rare germ line variants

  15. BACH1 Ser919Pro variant and breast cancer risk

    International Nuclear Information System (INIS)

    Vahteristo, Pia; Yliannala, Kristiina; Tamminen, Anitta; Eerola, Hannaleena; Blomqvist, Carl; Nevanlinna, Heli

    2006-01-01

    BACH1 (BRCA1-associated C-terminal helicase 1; also known as BRCA1-interacting protein 1, BRIP1) is a helicase protein that interacts in vivo with BRCA1, the protein product of one of the major genes for hereditary predisposition to breast cancer. Previously, two BACH1 germ line missense mutations have been identified in early-onset breast cancer patients with and without family history of breast and ovarian cancer. In this study, we aimed to evaluate whether there are BACH1 genetic variants that contribute to breast cancer risk in Finland. The BACH1 gene was screened for germ line alterations among probands from 43 Finnish BRCA1/2 negative breast cancer families. Recently, one of the observed common variants, Ser-allele of the Ser919Pro polymorphism, was suggested to associate with an increased breast cancer risk, and was here evaluated in an independent, large series of 888 unselected breast cancer patients and in 736 healthy controls. Six BACH1 germ line alterations were observed in the mutation analysis, but none of these were found to associate with the cancer phenotype. The Val193Ile variant that was seen in only one family was further screened in an independent series of 346 familial breast cancer cases and 183 healthy controls, but no additional carriers were observed. Individuals with the BACH1 Ser919-allele were not found to have an increased breast cancer risk when the Pro/Ser heterozygotes (OR 0.90; 95% CI 0.70–1.16; p = 0.427) or Ser/Ser homozygotes (OR 1.02; 95% CI 0.76–1.35; p = 0.91) were compared to Pro/Pro homozygotes, and there was no association of the variant with any breast tumor characteristics, age at cancer diagnosis, family history of cancer, or survival. Our results suggest that the BACH1 Ser919 is not a breast cancer predisposition allele in the Finnish study population. Together with previous studies, our results also indicate that although some rare germ line variants in BACH1 may contribute to breast cancer development, the

  16. Microbial fuel cells with highly active aerobic biocathodes

    Science.gov (United States)

    Milner, Edward M.; Popescu, Dorin; Curtis, Tom; Head, Ian M.; Scott, Keith; Yu, Eileen H.

    2016-08-01

    Microbial fuel cells (MFCs), which convert organic waste to electricity, could be used to make the wastewater infrastructure more energy efficient and sustainable. However, platinum and other non-platinum chemical catalysts used for the oxygen reduction reaction (ORR) at the cathode of MFCs are unsustainable due to their high cost and long-term degradation. Aerobic biocathodes, which use microorganisms as the biocatalysts for cathode ORR, are a good alternative to chemical catalysts. In the current work, high-performing aerobic biocathodes with an onset potential for the ORR of +0.4 V vs. Ag/AgCl were enriched from activated sludge in electrochemical half-cells poised at -0.1 and + 0.2 V vs. Ag/AgCl. Gammaproteobacteria, distantly related to any known cultivated gammaproteobacterial lineage, were identified as dominant in these working electrode biofilms (23.3-44.3% of reads in 16S rRNA gene Ion Torrent libraries), and were in very low abundance in non-polarised control working electrode biofilms (0.5-0.7%). These Gammaproteobacteria were therefore most likely responsible for the high activity of biologically catalysed ORR. In MFC tests, a high-performing aerobic biocathode increased peak power 9-fold from 7 to 62 μW cm-2 in comparison to an unmodified carbon cathode, which was similar to peak power with a platinum-doped cathode at 70 μW cm-2.

  17. Mutational analysis of the pumpkin (Cucurbita maxima) phloem exudate lectin, PP2 reveals Ser-104 is crucial for carbohydrate binding.

    Science.gov (United States)

    Bobbili, Kishore Babu; Bandari, Shyam; Grobe, Kay; Swamy, Musti J

    2014-07-18

    The pumpkin phloem lectin (PP2) is an RNA-binding, defense-related, chitooligosaccharide-specific, homodimeric lectin of Mr 48 kDa expressed at high concentrations in the sieve elements and companion cells of pumpkin (Cucurbita maxima). In the present study, PP2 was expressed in the methylotrophic yeast Pichia pastoris with the Saccharomyces α-factor sequence to direct the recombinant protein into the secretory pathway as a prerequisite for unimpaired folding and posttranslational glycosylation of recombinant PP2. Previous computational modeling and ligand docking studies predicted a putative chitooligosaccharide-binding site on the PP2 surface, which was divided into three subsites, with two amino acid residues in each subsite identified as possible candidates for interaction with chitooligosaccharides (CHOs). In this work, mutational analysis and hemagglutination assays were employed to verify the role of the predicted residues in the carbohydrate binding activity of the protein. The results obtained revealed that mutation of Ser-104 to Ala (S104A) at subsite-2 resulted in about 90% loss of agglutination activity of the protein, indicating that Ser-104 is crucial for the binding of CHOs to PP2. Also, L100A (at subsite-1) and K200A (at subsite-3) independently decreased the lectin activity by about 40%, indicating that these two residues also contribute significantly to sugar binding by PP2. Together, these findings confirm that all the three subsites contribute to varying degrees toward PP2-carbohydrate interaction, and confirm the validity of the computational model, as proposed earlier. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Telomerase activation by genomic rearrangements in high-risk neuroblastoma

    Science.gov (United States)

    Peifer, Martin; Hertwig, Falk; Roels, Frederik; Dreidax, Daniel; Gartlgruber, Moritz; Menon, Roopika; Krämer, Andrea; Roncaioli, Justin L.; Sand, Frederik; Heuckmann, Johannes M.; Ikram, Fakhera; Schmidt, Rene; Ackermann, Sandra; Engesser, Anne; Kahlert, Yvonne; Vogel, Wenzel; Altmüller, Janine; Nürnberg, Peter; Thierry-Mieg, Jean; Thierry-Mieg, Danielle; Mariappan, Aruljothi; Heynck, Stefanie; Mariotti, Erika; Henrich, Kai-Oliver; Glöckner, Christian; Bosco, Graziella; Leuschner, Ivo; Schweiger, Michal R.; Savelyeva, Larissa; Watkins, Simon C.; Shao, Chunxuan; Bell, Emma; Höfer, Thomas; Achter, Viktor; Lang, Ulrich; Theissen, Jessica; Volland, Ruth; Saadati, Maral; Eggert, Angelika; de Wilde, Bram; Berthold, Frank; Peng, Zhiyu; Zhao, Chen; Shi, Leming; Ortmann, Monika; Büttner, Reinhard; Perner, Sven; Hero, Barbara; Schramm, Alexander; Schulte, Johannes H.; Herrmann, Carl; O’Sullivan, Roderick J.; Westermann, Frank; Thomas, Roman K.; Fischer, Matthias

    2016-01-01

    Neuroblastoma is a malignant paediatric tumour of the sympathetic nervous system1. Roughly half of these tumours regress spontaneously or are cured by limited therapy. By contrast, high-risk neuroblastomas have an unfavourable clinical course despite intensive multimodal treatment, and their molecular basis has remained largely elusive2–4. Here we have performed whole-genome sequencing of 56 neuroblastomas (high-risk, n = 39; low-risk, n = 17) and discovered recurrent genomic rearrangements affecting a chromosomal region at 5p15.33 proximal of the telomerase reverse transcriptase gene (TERT). These rearrangements occurred only in high-risk neuroblastomas (12/39, 31%) in a mutually exclusive fashion with MYCN amplifications and ATRX mutations, which are known genetic events in this tumour type1,2,5. In an extended case series (n = 217), TERT rearrangements defined a subgroup of high-risk tumours with particularly poor outcome. Despite a large structural diversity of these rearrangements, they all induced massive transcriptional upregulation of TERT. In the remaining high-risk tumours, TERT expression was also elevated in MYCN-amplified tumours, whereas alternative lengthening of telomeres was present in neuroblastomas without TERT or MYCN alterations, suggesting that telomere lengthening represents a central mechanism defining this subtype. The 5p15.33 rearrangements juxtapose the TERT coding sequence to strong enhancer elements, resulting in massive chromatin remodelling and DNA methylation of the affected region. Supporting a functional role of TERT, neuroblastoma cell lines bearing rearrangements or amplified MYCN exhibited both upregulated TERT expression and enzymatic telomerase activity. In summary, our findings show that remodelling of the genomic context abrogates transcriptional silencing of TERT in high-risk neuroblastoma and places telomerase activation in the centre of transformation in a large fraction of these tumours. PMID:26466568

  19. Subnanomolar Sensitivity of Filter Paper-Based SERS Sensor for Pesticide Detection by Hydrophobicity Change of Paper Surface.

    Science.gov (United States)

    Lee, Minwoo; Oh, Kyudeok; Choi, Han-Kyu; Lee, Sung Gun; Youn, Hye Jung; Lee, Hak Lae; Jeong, Dae Hong

    2018-01-26

    As a cost-effective approach for detecting trace amounts of pesticides, filter paper-based SERS sensors have been the subject of intensive research. One of the hurdles to overcome is the difficulty of retaining nanoparticles on the surface of the paper because of the hydrophilic nature of the cellulose fibers in paper. This reduces the sensitivity and reproducibility of paper-based SERS sensors due to the low density of nanoparticles and short retention time of analytes on the paper surface. In this study, filter paper was treated with alkyl ketene dimer (AKD) to modify its property from hydrophilic to hydrophobic. AKD treatment increased the contact angle of the aqueous silver nanoparticle (AgNP) dispersion, which consequently increased the density of AgNPs. The retention time of the analyte was also increased by preventing its rapid absorption into the filter paper. The SERS signal was strongly enhanced by the increased number of SERS hot spots owing to the increased density of AgNPs on a small contact area of the filter surface. The reproducibility and sensitivity of the SERS signal were optimized by controlling the distribution of AgNPs on the surface of the filter paper by adjusting the concentration of the AgNP solution. Using this SERS sensor with a hydrophobicity-modified filter paper, the spot-to-spot variation of the SERS intensity of 25 spots of 4-aminothiophenol was 6.19%, and the limits of detection of thiram and ferbam as test pesticides were measured to be 0.46 nM and 0.49 nM, respectively. These proof-of-concept results indicate that this paper-based SERS sensor can serve for highly sensitive pesticide detection with low cost and easy fabrication.

  20. Incorporation of multilayered silver nanoparticles into polymer brushes as 3-dimensional SERS substrates and their application for bacteria detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qian; Wang, Xiang-Dong; Tian, Ting; Chu, Li-Qiang, E-mail: chuliqiang@tust.edu.cn

    2017-06-15

    Highlights: • POEGMA/AgNPs composite film prepared via the in-stacking method is employed as 3D SERS substrate. • Control over POEGMA chain length is achieved via SI-ATRP method. • Influence of POEGMA chain length and in-stacking process on SERS performance is investigated. • The 3D SERS substrate is used for the ultrasensitive detection of ATP and S. aureus. - Abstract: Surface-enhanced Raman scattering (SERS) sensors have been extensively studied for ultrasensitive detection of diverse chemical or biological analytes. Facile fabrication of highly sensitive SERS substrates is believed to be of crucial importance in these analytical applications. In this regard, the preparation of 3-dimensional (3D) SERS substrates are explored via the incorporation of multilayered silver nanoparticles (AgNPs) into poly (oligo(ethylene glycol) methacrylate) (POEGMA) brushes by repeating the immersion-rinsing-drying steps for different lengths of time (i.e., the so-called in-stacking method). The POEGMA brushes of different chain lengths are synthesized by surface-initiated atom transfer radical polymerization (ATRP) with various reaction time. The resulting POEGMA/AgNP nanocomposites are characterized by FE-SEM, UV–vis and Raman spectroscopy. FE-SEM and UV–vis results indicate that the AgNPs are successfully incorporated into the POEGMA brushes with a 3D configuration. The nanocomposite films are employed as SERS substrates for the detection of a Raman reporter molecule (i.e., 4-aminothiophenol), giving rise to an enhancement factor of up to 1.29 × 10{sup 7} and also having relatively good uniformity and reproducibility. The obtained 3D SERS substrates are also used for the detection of a typical gram-positive bacterium, Staphylococcus aureus. The limit of detection is found to be as low as ca. 8 CFU/mL.

  1. Passive and Active Monitoring on a High Performance Research Network

    International Nuclear Information System (INIS)

    Matthews, Warren

    2001-01-01

    The bold network challenges described in ''Internet End-to-end Performance Monitoring for the High Energy and Nuclear Physics Community'' presented at PAM 2000 have been tackled by the intrepid administrators and engineers providing the network services. After less than a year, the BaBar collaboration has collected almost 100 million particle collision events in a database approaching 165TB (Tera=10 12 ). Around 20TB has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, for processing and around 40 TB of simulated events have been imported to SLAC from Lawrence Livermore National Laboratory (LLNL). An unforseen challenge has arisen due to recent events and highlighted security concerns at DoE funded labs. New rules and regulations suggest it is only a matter of time before many active performance measurements may not be possible between many sites. Yet, at the same time, the importance of understanding every aspect of the network and eradicating packet loss for high throughput data transfers has become apparent. Work at SLAC to employ passive monitoring using netflow and OC3MON is underway and techniques to supplement and possibly replace the active measurements are being considered. This paper will detail the special needs and traffic characterization of a remarkable research project, and how the networking hurdles have been resolved (or not) to achieve the required high data throughput. Results from active and passive measurements will be compared, and methods for achieving high throughput and the effect on the network will be assessed along with tools that directly measure throughput and applications used to actually transfer data

  2. Passive and Active Monitoring on a High Performance Research Network.

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Warren

    2001-05-01

    The bold network challenges described in ''Internet End-to-end Performance Monitoring for the High Energy and Nuclear Physics Community'' presented at PAM 2000 have been tackled by the intrepid administrators and engineers providing the network services. After less than a year, the BaBar collaboration has collected almost 100 million particle collision events in a database approaching 165TB (Tera=10{sup 12}). Around 20TB has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, for processing and around 40 TB of simulated events have been imported to SLAC from Lawrence Livermore National Laboratory (LLNL). An unforseen challenge has arisen due to recent events and highlighted security concerns at DoE funded labs. New rules and regulations suggest it is only a matter of time before many active performance measurements may not be possible between many sites. Yet, at the same time, the importance of understanding every aspect of the network and eradicating packet loss for high throughput data transfers has become apparent. Work at SLAC to employ passive monitoring using netflow and OC3MON is underway and techniques to supplement and possibly replace the active measurements are being considered. This paper will detail the special needs and traffic characterization of a remarkable research project, and how the networking hurdles have been resolved (or not!) to achieve the required high data throughput. Results from active and passive measurements will be compared, and methods for achieving high throughput and the effect on the network will be assessed along with tools that directly measure throughput and applications used to actually transfer data.

  3. Disulphide linkage: To get cleaved or not? Bulk and nano copper based SERS of cystine

    Science.gov (United States)

    P. J., Arathi; Seemesh, Bhaskar; Rajendra Kumar Reddy, G.; Suresh Kumar, P.; Ramanathan, V.

    2018-05-01

    Different nano-structures of noble metals have been the conventional substrates for carrying out Surface Enhanced Raman Spectroscopy (SERS). In this paper we examine electrodeposited copper (Cu) nano-structures on pencil graphite as novel substrate to carry out SERS measurements by considering L-cystine (Cys-Cys) (dimer of the amino acid cysteine) as the probe. The formation of monolayer of the probe molecule on the substrates was confirmed using cyclic voltammetric measurements. Mode of adsorption of Cys-Cys was observed to be different on bulk Cu (taken in the wire form) and nano-structured Cu on pencil graphite. Whereas in the former the disulphide bond of Cys-Cys remained intact, it got cleaved when Cys-Cys was adsorbed on electrodeposited copper indicating the activated nature of the nano-structure compared to bulk copper. Csbnd S stretching mode of vibration underwent blue shift in Cys-Cys adsorbed on Cu on pencil graphite vis-à-vis Cys-Cys adsorbed on Cu wire. Further evidence on the cleavage of the Csbnd S bond on an activated substrate was obtained by considering a bimetallic substrate comprising of silver on copper which was electrodeposited on pencil graphite. Our studies have demonstrated that nano-copper surface is an excellent substrate for SERS giving 200 μM as lower detection limit for Cys-Cys.

  4. The effect of silver thickness on the enhancement of polymer based SERS substrates

    International Nuclear Information System (INIS)

    Schneidewind, H; Weber, K; Zeisberger, M; Hübner, U; Dellith, A; Cialla-May, D; Mattheis, R; Popp, J

    2014-01-01

    We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films. (paper)

  5. Hierarchically assembled Au microspheres and sea urchin-like architectures: formation mechanism and SERS study.

    Science.gov (United States)

    Wang, Xiansong; Yang, Da-Peng; Huang, Peng; Li, Min; Li, Chao; Chen, Di; Cui, Daxiang

    2012-12-21

    The hierarchically assembled Au microspheres/sea urchin-like structures have been synthesized in aqueous solution at room temperature with and without proteins (bovine serum albumin, BSA) as mediators. The average diameter of an individual Au microsphere is 300-600 nm, which is composed of some compact nanoparticles with an average diameter of about 15 nm. Meanwhile, the sea urchin-like Au architecture exhibits an average diameter of 600-800 nm, which is made up of some nanopricks with an average length of 100-200 nm. These products are characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electronic microscopy (TEM). It is found that the BSA and ascorbic acid (AA) have great effects on the morphology of the resulting products. Two different growth mechanisms are proposed. The study on surface enhanced Raman scattering (SERS) activities is also carried out between Au microspheres and Au sea urchin-like architectures. It is found that Au urchin-like architectures possess much higher SERS activity than the Au microspheres. Our work may shed light on the design and synthesis of hierarchically self-assembled 3D micro/nano-architectures for SERS, catalysis and biosensors.

  6. Unveiling NIR Aza-Boron-Dipyrromethene (BODIPY) Dyes as Raman Probes: Surface-Enhanced Raman Scattering (SERS)-Guided Selective Detection and Imaging of Human Cancer Cells.

    Science.gov (United States)

    Adarsh, Nagappanpillai; Ramya, Adukkadan N; Maiti, Kaustabh Kumar; Ramaiah, Danaboyina

    2017-10-12

    The development of new Raman reporters has attracted immense attention in diagnostic research based on surface enhanced Raman scattering (SERS) techniques, which is a well established method for ultrasensitive detection through molecular fingerprinting and imaging. Herein, for the first time, we report the unique and efficient Raman active features of the selected aza-BODIPY dyes 1-6. These distinctive attributes could be extended at the molecular level to allow detection through SERS upon adsorption onto nano-roughened gold surface. Among the newly revealed Raman reporters, the amino substituted derivative 4 showed high signal intensity at very low concentrations (ca. 0.4 μm for 4-Au). Interestingly, an efficient nanoprobe has been constructed by using gold nanoparticles as SERS substrate, and 4 as the Raman reporter (4-Au@PEG), which unexpectedly showed efficient recognition of three human cancer cells (lung: A549, cervical: HeLa, Fibrosarcoma: HT-1080) without any specific surface marker. We observed well reflected and resolved Raman mapping and characteristic signature peaks whereas, such recognition was not observed in normal fibroblast (3T3L1) cells. To confirm these findings, a SERS nanoprobe was conjugated with a specific tumour targeting marker, EGFR (Epidermal Growth Factor Receptor), a well known targeted agent for Human Fibrosarcoma (HT1080). This nanoprobe efficiently targeted the surface marker of HT1080 cells, threreby demonstrating its use as an ultrasensitive Raman probe for detection and targeted imaging, leaving normal cells unaffected. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ser80Ile mutation and a concurrent Pro25Leu variant of the VHL gene in an extended Hungarian von Hippel-Lindau family

    Directory of Open Access Journals (Sweden)

    Fazakas Ferenc

    2008-04-01

    Full Text Available Abstract Von Hippel-Lindau disease (VHL is a rare autosomal dominant disease characterized by development of cystic and tumorous lesions at multiple sites, including the brain, spinal cord, kidneys, adrenals, pancreas, epididymis and eyes. The clinical phenotype results from molecular abnormalities of the VHL tumor suppressor gene, mapped to human chromosome 3p25-26. The VHL gene encodes two functionally active VHL proteins due to the presence of two translational initiation sites separated by 53 codons. The majority of disease-causing mutations have been detected downstream of the second translational initiation site, but there are conflicting data as to whether few mutations located in the first 53 codons, such as the Pro25Leu could have a pathogenic role. In this paper we report a large Hungarian VHL type 2 family consisting of 32 members in whom a disease-causing AGT80AAT (Ser80Ile c.239G>A, p.Ser80Ile mutation, but not the concurrent CCT25CTT (Pro25Leu c.74C>T, p.Pro25Leu variant co-segregated with the disease. To our knowledge, the Ser80Ile mutation has not been previously described in VHL type 2 patients with high risk of pheochromocytoma and renal cell cancer. Therefore, this finding represents a novel genotype-phenotype association and VHL kindreds with Ser80Ile mutation will require careful surveillance for pheochromocytoma. We concluded that the Pro25Leu variant is a rare, neutral variant, but the presence such a rare gene variant may make genetic counseling difficult.

  8. Ag nanoparticles agargel nanocomposites for SERS detection of cultural heritage interest pigments

    Science.gov (United States)

    Amato, F.; Micciche', C.; Cannas, M.; Gelardi, F. M.; Pignataro, B.; Li Vigni, M.; Agnello, S.

    2018-02-01

    Agarose gel (agargel) composites with commercial and laboratory made silver nanoparticles were prepared by a wet solution method at room temperature. The gel composites were used for pigment extraction and detection by Raman spectroscopy. Red (alizarin) and violet (crystal violet) pigments deposited on paper were extracted by the composites and were investigated by micro-Raman spectroscopy. Evaluation was carried out of the surface-enhanced Raman spectroscopy (SERS) effect induced by the silver nanoparticles embedded in the gel. A kinetic approach as a function of time was used to determine the efficiency of pigments extraction by composites deposition. A non-invasive extraction process of few minutes is demonstrated. This process induces active SERS for both used pigments. The reported results show the full exploitability of agargel silver nanoparticle composites for the extraction of pigments from paper based artworks.

  9. Tobacco Stem-Based Activated Carbons for High Performance Supercapacitors

    Science.gov (United States)

    Xia, Xiaohong; Liu, Hongbo; Shi, Lei; He, Yuede

    2012-09-01

    Tobacco stem-based activated carbons (TS-ACs) were prepared by simple KOH activation and their application as electrodes in the electrical double layer capacitor (EDLC) performed successfully. The BET surface area, pore volume, and pore size distribution of the TS-ACs were evaluated based on N2 adsorption isotherms at 77 K. The surface area of the obtained activated carbons varies over a wide range (1472.8-3326.7 m2/g) and the mesoporosity was enhanced significantly as the ratio of KOH to tobacco stem (TS) increased. The electrochemical behaviors of series TS-ACs were characterized by means of galvanostatic charging/discharging, cyclic voltammetry, and impedance spectroscopy. The correlation between electrochemical properties and pore structure was investigated. A high specific capacitance value as 190 F/g at 1 mA/cm2 was obtained in 1 M LiPF6-EC/DMC/DEC electrolyte solution. Furthermore, good performance is also achieved even at high current densities. A development of new use for TS into a valuable energy storage material is explored.

  10. High Performance Activity Practices in Small Firms in Romania

    Directory of Open Access Journals (Sweden)

    Gabriela ŢUŢUEANU

    2014-12-01

    Full Text Available High Performance Activity Practices in Small Firms in Romania Abstract: High performance activity practices (HPAPs are human resource management activities aimed at stimulating employee and organisational performance. The application of HPAPs is not widespread in small organisations. We examine whether the implementation of coherent bundles of HPAPs (aimed at employee ability, employee motivation or at the opportunity to perform depends on the scarcity of resources, as reflected in the size of the company, and on strategic decision-making in small firms related to the owner’s expertise and attitudes. In our research, a total of 224 employees from 50 small organisations were asked to rate the presence of HPAPs in their organisation. These averaged perceptions were linked to information provided by the owner–managers on the size of their firm and their own expertise and attitudes. The findings support that smaller but coherent bundles of HPAPs can be found in small organisations and that the implementation of these bundles depends on available resources, strategic decision-making and the combination of the two. These findings highlight the need to integrate the notions of resource poverty and strategic decision-making to understand the uptake of bundles of HPAPs within small firms.

  11. Sensitive SERS-pH sensing in biological media using metal carbonyl functionalized planar substrates.

    Science.gov (United States)

    Kong, Kien Voon; Dinish, U S; Lau, Weber Kam On; Olivo, Malini

    2014-04-15

    Conventional nanoparticle based Surface enhanced Raman scattering (SERS) technique for pH sensing often fails due to the aggregation of particles when detecting in acidic medium or biosamples having high ionic strength. Here, We develop SERS based pH sensing using a novel Raman reporter, arene chromium tricarbonyl linked aminothiophenol (Cr(CO)3-ATP), functionalized onto a nano-roughened planar substrates coated with gold. Unlike the SERS spectrum of the ATP molecule that dominates in the 400-1700 cm(-1) region, which is highly interfered by bio-molecules signals, metal carbonyl-ATP (Cr(CO)3)-ATP) offers the advantage of monitoring the pH dependent strong CO stretching vibrations in the mid-IR (1800-2200 cm(-1)) range. Raman signal of the CO stretching vibrations at ~1820 cm(-1) has strong dependency on the pH value of the environment, where its peak undergo noticeable shift as the pH of the medium is varied from 3.0 to 9.0. The sensor showed better sensitivity in the acidic range of the pH. We also demonstrate the pH sensing in a urine sample, which has high ionic strength and our data closely correlate to the value obtained from conventional sensor. In future, this study may lead to a sensitive chip based pH sensing platform in bio-fluids for the early diagnosis of diseases. © 2013 Published by Elsevier B.V.

  12. Sulfurized activated carbon for high energy density supercapacitors

    Science.gov (United States)

    Huang, Yunxia; Candelaria, Stephanie L.; Li, Yanwei; Li, Zhimin; Tian, Jianjun; Zhang, Lili; Cao, Guozhong

    2014-04-01

    Sulfurized activated carbon (SAC), made by coating the pore surface with thiophenic sulfur functional groups from the pyrolysis of sulfur flakes, were characterized and tested for supercapacitor applications. From X-ray photoelectron spectroscopy (XPS), the sulfur content in the SAC was found to be 2.7 at%. Electrochemical properties from potentiostatic and galvanostatic measurements, and electrochemical impedance spectroscopy (EIS) were used to evaluate the effect of sulfur on porous carbon electrodes. The SAC electrode exhibits better conductivity, and an obvious increase in specific capacitance that is almost 40% higher than plain activated carbons (ACs) electrode at a high current density of 1.4 A g-1. The proposed mechanism for improved conductivity and capacitive performance due to the sulfur functional groups on ACs will be discussed.

  13. High active waste (HAW) data report January-June 1991

    International Nuclear Information System (INIS)

    Duijves, K.A.

    1992-04-01

    Data are presented from the High Active Waste (HAW) experiment, a large-scale, in situ test being performed underground at the Asse salt mine in Remlingen, FRG. These data include selected field information, the test configuration, instrumentation activities and comprehensive results from a large number of gauges. The results are measured data obtained from gap meters, thermocouples, linear displacement transducers, extensometers, inclinometers and pressure gauges. Data certification practices have been described together with the quality assurance of the data reduction and of the data base management system. The experiment began on November 8, 1988 and will continue for five years. Data in this report cover the period from January 1st, 1991 to June 30, 1991. (author). 4 refs.; 43 figs.; 8 tabs

  14. Actively Closing the Gap? Social Class, Organized Activities, and Academic Achievement in High School

    Science.gov (United States)

    Morris, David S.

    2015-01-01

    Participation in Organized Activities (OA) is associated with positive behavioral and developmental outcomes in children. However, less is known about how particular aspects of participation affect the academic achievement of high school students from different social class positions. Using the Education Longitudinal Study of 2002, this study…

  15. 78 FR 70567 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final...

    Science.gov (United States)

    2013-11-26

    ... Frequency and Ultra High Frequency Active SONAR Technology; Final Programmatic Environmental Assessment and... each alternative on the human and natural environments. FOR FURTHER INFORMATION CONTACT: If you have... Programmatic Environmental Assessment The scope of the PEA focuses on potential impacts associated with the...

  16. Acridinium esters as high-specific-activity labels in immunoassay

    International Nuclear Information System (INIS)

    Weeks, I.; Beheshti, I.; McCapra, F.; Campbell, A.K.; Woodhead, J.S.

    1983-01-01

    A chemiluminescent acridinium ester has been synthesized that reacts spontaneously with proteins to yield stable, immunoreactive derivatives of high specific activity. The compound has been used to prepare chemiluminescent monoclonal antibodies to human alpha 1-fetoprotein having average incorporation ratios as great as 2.8 mol of label per mole of antibody, which corresponds to a detection limit of approximately 8 X 10(-19) mol. These antibodies have been used in the preliminary development of a two-site immunochemiluminometric assay for human alpha 1-fetoprotein, which requires only a 30-min incubation and a quantification time of 5 s per sample

  17. The denitration of simulated fast reactor highly active liquor waste

    International Nuclear Information System (INIS)

    Saum, C.J.; Ford, L.H.; Platts, N.

    1981-11-01

    Vitrification of the highly active arisings from PFR fuel reprocessing is proposed as the optimum long-term solution to the disposal problem. During vitrification ruthenium volatilises as the tetroxide. Evidence is presented which indicates that a substantial reduction in volatility can be effected by denitration of the liquid feed by treatment with formic acid. The kinetics and stoichiometry of the reactions involved in denitration are examined and empirical rate equations developed. The predictions of the empirical rate equation have been confirmed using a one-tenth scale continuous denitrator, thus giving confidence for the design of full-scale units. (author)

  18. Production of N-13 labeled compounds with high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kazutoshi; Sasaki, Motoji; Yoshida, Yuichiro; Haradahira, Terushi; Inoue, Osamu [National Inst. of Radiological Sciences, Chiba (Japan)

    1997-03-01

    Nitrogen-13 was produced by irradiating ultra pure water saturated with a pure gas (N2, O2, He, H2) with 18 MeV protons. Ion species generated by irradiation were analyzed with radio ion chromatography systems. An automated equipment was developed to synthesize anhydrous (13N)NH3 as a synthetic precursor and (13N)p-nitrophenyl carbamate ((13N)NPC) as a model compound, using the (13N)NH3. The radiochemical yield and specific activity of (13N)NPC was high enough to carry out the receptor study with PET. (author)

  19. Borosilicate glasses for the high activity waste vetrification

    International Nuclear Information System (INIS)

    Cantale, C.; Donato, A.; Guidi, G.

    1984-01-01

    Some results concerning the researches carried out on the high-level wastes vitrification at ENEA, Comb-Mepis-Rifiu laboratory are reported. A fission product solution referred to power plant nuclear fuel reprocessing has been selected and simulated with no radioactive chemicals. Some glass composition have been tested for the vitrification of this solution, the best of them being taken into consideration for real active tests at the hot bench scale plant ESTER in Ispra. The final glasses have been characterized from the chemical and physical point of view; moreover some microstructural investigations have been performed in order to identify few microsegregations and to test the degree of amorphousness of the products

  20. Neutron activation analysis of high-purity zinc

    International Nuclear Information System (INIS)

    Khodzhamberdyeva, A.A.; Usmanova, M.M.; Gil'bert, Eh.N.; Ivanov, I.M.; Yankovskaya, T.A.; Kholyavko, E.P.

    1987-01-01

    The methods of neutron activation analysis of high-purity zinc with preliminary separation of the zinc base using extraction by trialkylbenzylammonium rhodanide in carbon tetrachloride from 0.5-2.0 M nitric acid solutions is developed. Only rhenium is quantitatively extracted together with zinc. Gold, iridium and molybdenum are extracted to 50-60%, and selenium - to 20%. The Na, K, La, Cr, Sc, Co, Cs, Rb, Fe, Zr, Sn, Te, As, Cd, Hf, W, Sb, Sm impurities remain in the aqueous phase. The methods permits to determine the impurities above with detection limits from 1x10 -6 to 4x10 -11 g

  1. Active x-ray optics for high resolution space telescopes

    Science.gov (United States)

    Doel, Peter; Atkins, Carolyn; Brooks, D.; Feldman, Charlotte; Willingale, Richard; Button, Tim; Rodriguez Sanmartin, Daniel; Meggs, Carl; James, Ady; Willis, Graham; Smith, Andy

    2017-11-01

    The Smart X-ray Optics (SXO) Basic Technology project started in April 2006 and will end in October 2010. The aim is to develop new technologies in the field of X-ray focusing, in particular the application of active and adaptive optics. While very major advances have been made in active/adaptive astronomical optics for visible light, little was previously achieved for X-ray optics where the technological challenges differ because of the much shorter wavelengths involved. The field of X-ray astronomy has been characterized by the development and launch of ever larger observatories with the culmination in the European Space Agency's XMM-Newton and NASA's Chandra missions which are currently operational. XMM-Newton uses a multi-nested structure to provide modest angular resolution ( 10 arcsec) but large effective area, while Chandra sacrifices effective area to achieve the optical stability necessary to provide sub-arc second resolution. Currently the European Space Agency (ESA) is engaged in studies of the next generation of X-ray space observatories, with the aim of producing telescopes with increased sensitivity and resolution. To achieve these aims several telescopes have been proposed, for example ESA and NASA's combined International X-ray Observatory (IXO), aimed at spectroscopy, and NASA's Generation-X. In the field of X-ray astronomy sub 0.2 arcsecond resolution with high efficiency would be very exciting. Such resolution is unlikely to be achieved by anything other than an active system. The benefits of a such a high resolution would be important for a range of astrophysics subjects, for example the potential angular resolution offered by active X-ray optics could provide unprecedented structural imaging detail of the Solar Wind bowshock interaction of comets, planets and similar objects and auroral phenomena throughout the Solar system using an observing platform in low Earth orbit. A major aim of the SXO project was to investigate the production of thin

  2. DataHigh: graphical user interface for visualizing and interacting with high-dimensional neural activity

    Science.gov (United States)

    Cowley, Benjamin R.; Kaufman, Matthew T.; Butler, Zachary S.; Churchland, Mark M.; Ryu, Stephen I.; Shenoy, Krishna V.; Yu, Byron M.

    2013-12-01

    Objective. Analyzing and interpreting the activity of a heterogeneous population of neurons can be challenging, especially as the number of neurons, experimental trials, and experimental conditions increases. One approach is to extract a set of latent variables that succinctly captures the prominent co-fluctuation patterns across the neural population. A key problem is that the number of latent variables needed to adequately describe the population activity is often greater than 3, thereby preventing direct visualization of the latent space. By visualizing a small number of 2-d projections of the latent space or each latent variable individually, it is easy to miss salient features of the population activity. Approach. To address this limitation, we developed a Matlab graphical user interface (called DataHigh) that allows the user to quickly and smoothly navigate through a continuum of different 2-d projections of the latent space. We also implemented a suite of additional visualization tools (including playing out population activity timecourses as a movie and displaying summary statistics, such as covariance ellipses and average timecourses) and an optional tool for performing dimensionality reduction. Main results. To demonstrate the utility and versatility of DataHigh, we used it to analyze single-trial spike count and single-trial timecourse population activity recorded using a multi-electrode array, as well as trial-averaged population activity recorded using single electrodes. Significance. DataHigh was developed to fulfil a need for visualization in exploratory neural data analysis, which can provide intuition that is critical for building scientific hypotheses and models of population activity.

  3. DataHigh: graphical user interface for visualizing and interacting with high-dimensional neural activity.

    Science.gov (United States)

    Cowley, Benjamin R; Kaufman, Matthew T; Butler, Zachary S; Churchland, Mark M; Ryu, Stephen I; Shenoy, Krishna V; Yu, Byron M

    2013-12-01

    Analyzing and interpreting the activity of a heterogeneous population of neurons can be challenging, especially as the number of neurons, experimental trials, and experimental conditions increases. One approach is to extract a set of latent variables that succinctly captures the prominent co-fluctuation patterns across the neural population. A key problem is that the number of latent variables needed to adequately describe the population activity is often greater than 3, thereby preventing direct visualization of the latent space. By visualizing a small number of 2-d projections of the latent space or each latent variable individually, it is easy to miss salient features of the population activity. To address this limitation, we developed a Matlab graphical user interface (called DataHigh) that allows the user to quickly and smoothly navigate through a continuum of different 2-d projections of the latent space. We also implemented a suite of additional visualization tools (including playing out population activity timecourses as a movie and displaying summary statistics, such as covariance ellipses and average timecourses) and an optional tool for performing dimensionality reduction. To demonstrate the utility and versatility of DataHigh, we used it to analyze single-trial spike count and single-trial timecourse population activity recorded using a multi-electrode array, as well as trial-averaged population activity recorded using single electrodes. DataHigh was developed to fulfil a need for visualization in exploratory neural data analysis, which can provide intuition that is critical for building scientific hypotheses and models of population activity.

  4. DataHigh: Graphical user interface for visualizing and interacting with high-dimensional neural activity

    Science.gov (United States)

    Cowley, Benjamin R.; Kaufman, Matthew T.; Butler, Zachary S.; Churchland, Mark M.; Ryu, Stephen I.; Shenoy, Krishna V.; Yu, Byron M.

    2014-01-01

    Objective Analyzing and interpreting the activity of a heterogeneous population of neurons can be challenging, especially as the number of neurons, experimental trials, and experimental conditions increases. One approach is to extract a set of latent variables that succinctly captures the prominent co-fluctuation patterns across the neural population. A key problem is that the number of latent variables needed to adequately describe the population activity is often greater than three, thereby preventing direct visualization of the latent space. By visualizing a small number of 2-d projections of the latent space or each latent variable individually, it is easy to miss salient features of the population activity. Approach To address this limitation, we developed a Matlab graphical user interface (called DataHigh) that allows the user to quickly and smoothly navigate through a continuum of different 2-d projections of the latent space. We also implemented a suite of additional visualization tools (including playing out population activity timecourses as a movie and displaying summary statistics, such as covariance ellipses and average timecourses) and an optional tool for performing dimensionality reduction. Main results To demonstrate the utility and versatility of DataHigh, we used it to analyze single-trial spike count and single-trial timecourse population activity recorded using a multi-electrode array, as well as trial-averaged population activity recorded using single electrodes. Significance DataHigh was developed to fulfill a need for visualization in exploratory neural data analysis, which can provide intuition that is critical for building scientific hypotheses and models of population activity. PMID:24216250

  5. Active Photonic crystal fibers for high power applications

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin

    The photonic crystal ber technology provides means to realize bers optimized for high power operation, due to the large single-mode cores and the unique design exibility of the microstructure. The work presented in this thesis focuses on improving the properties of active photonic crystal bers...... contributed to the compounding of new and improved material compositions. The second part is an investigation of pump absorption in photonic crystal bers, demonstrating that the microstructure in photonic crystal bers improves the pump absorption by up to a factor of two compared to step-index bers....... This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential...

  6. High Frequency Active Auroral Research Program (HAARP) Imager

    Science.gov (United States)

    1993-09-30

    T-3 HCTL!; *WR-EN HCTL@ F- 3 HC7L! ; * HACK H(TL-@ F-4 HCTL!; ]NIiT-HOST 00 HB! F8 HCrL!; DSP-RESET INIT-HOST HCTL@ DUP F-6 HCTh! T-6 HCTU! DSP-IRQB...CONSTANTPS2 PI_HI P2-11 OR 3_-1O OR TG..LO OR CONSTANT PS3 P1I.,O P2_.i OR P3..LO OR TG_.LO OR CONSTANT PS4 PlLO P21-1I OR P3_H1 OR TGIIl OR CONSTANTPS5 P1_LO...CONSTANT PSTATEI PS2 SER-IDLE OR CONSTANT PSTATE2 PS3 SERIDLE OR CONSTANT PSTATE3 PS4 SERIDLE OR CONSTANT PSTATE4 PS5 SERIDLE OR CONSTANT PSTATES PS6

  7. Patchy silica-coated silver nanowires as SERS substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hunyadi Murph, Simona E.; Murphy, Catherine J.

    2013-05-08

    We report a class of core-shell nanomaterials that can be used as efficient surface-enhancement Raman scattering (SERS) substrates. The core consists of silver nanowires, prepared through a chemical reduction process, that are used to capture 4- mercaptobenzoic acid (4-MBA), a model analyte. The shell was prepared through a modified Stöber method and consists of patchy or full silica coats. The formation of silica coats was monitored via transmission electron microscopy, UV-visible spectroscopy and phase-analysis light scattering for measuring effective surface charge. Surprisingly, the patchy silica coated silver nanowires are better SERS substrate than silver nanowires; nanomolar concentration of 4-MBA can be detected. In addition, “nano-matryoshka” configurations were used to quantitate/explore the effect of the electromagnetic field at the tips of the nanowire (“hot spots”) in the Raman scattering experiment.

  8. Applications of the surface enhanced Raman scattering (SERS)

    International Nuclear Information System (INIS)

    Picquart, M.; Haro P, E.; Bernard, S.

    2007-01-01

    Full text: Vibration spectroscopy techniques are used for many times to identify substances, determine molecular structure and quantify them, independently of their physical state. Raman spectroscopy as infrared absorption permit to access the vibration energy levels of molecules. In the second case, the permanent dipolar moment is involved while in the first one it is the polarizability (and the induced dipolar moment). Unfortunately, the classical Raman spectroscopy is low sensitive in particular in the case of biological molecules. On the opposite, the surface enhanced Raman spectroscopy (SERS) offers great potentialities. In this case, the molecules are adsorbed on a rough surface or on nanoparticles of gold or silver and the: signal can be increased by a factor of 10 7 to 10 8 . Moreover, the spectral enhancement is greater for the vibrations of the functional group of the molecule adsorbed on the substrate. In this work, we present the main theoretical bases of SERS, and some results obtain on different systems. (Author)

  9. Patchy silica-coated silver nanowires as SERS substrates

    International Nuclear Information System (INIS)

    Hunyadi Murph, Simona E.; Murphy, Catherine J.

    2013-01-01

    We report a class of core–shell nanomaterials that can be used as efficient surface-enhancement Raman scattering (SERS) substrates. The core consists of silver nanowires, prepared through a chemical reduction process, that are used to capture 4-mercaptobenzoic acid (4-MBA), a model analyte. The shell was prepared through a modified Stöber method and consists of patchy or full silica coats. The formation of silica coats was monitored via transmission electron microscopy, UV–visible spectroscopy, and phase-analysis light-scattering for measuring effective surface charge. Surprisingly, the patchy silica-coated silver nanowires are better SERS substrate than silver nanowires; nanomolar concentration of 4-MBA can be detected. In addition, “nano-matryoshka” configurations were used to quantitate/explore the effect of the electromagnetic field at the tips of the nanowire (“hot spots”) in the Raman scattering experiment.

  10. La polémica sobre el ser en el Avicena y Averroes latinos

    OpenAIRE

    García-Marqués, A. (Alfonso)

    1987-01-01

    Fiosofía medieval; recepción del aristotelismo árabe en Occidente; metafísica; aristotelismo platonizante; esencia; universal; accidentalidad del ser; ser y esencia; ser veritativo y ser extramental; crítica de Averroes a Avicena.

  11. SERS-barcoded colloidal gold NP assemblies as imaging agents for use in biodiagnostics

    Science.gov (United States)

    Dey, Priyanka; Olds, William; Blakey, Idriss; Thurecht, Kristofer J.; Izake, Emad L.; Fredericks, Peter M.

    2014-03-01

    There is a growing need for new biodiagnostics that combine high throughput with enhanced spatial resolution and sensitivity. Gold nanoparticle (NP) assemblies with sub-10 nm particle spacing have the benefits of improving detection sensitivity via Surface enhanced Raman scattering (SERS) and being of potential use in biomedicine due to their colloidal stability. A promising and versatile approach to form solution-stable NP assemblies involves the use of multi-branched molecular linkers which allows tailoring of the assembly size, hot-spot density and interparticle distance. We have shown that linkers with multiple anchoring end-groups can be successfully employed as a linker to assemble gold NPs into dimers, linear NP chains and clustered NP assemblies. These NP assemblies with diameters of 30-120 nm are stable in solution and perform better as SERS substrates compared with single gold NPs, due to an increased hot-spot density. Thus, tailored gold NP assemblies are potential candidates for use as biomedical imaging agents. We observed that the hot-spot density and in-turn the SERS enhancement is a function of the linker polymer concentration and polymer architecture. New deep Raman techniques like Spatially Offset Raman Spectroscopy (SORS) have emerged that allow detection from beneath diffusely scattering opaque materials, including biological media such as animal tissue. We have been able to demonstrate that the gold NP assemblies could be detected from within both proteinaceous and high lipid containing animal tissue by employing a SORS technique with a backscattered geometry.

  12. Quantitative SERS Detection of Dopamine in Cerebrospinal Fluid by Dual-Recognition-Induced Hot Spot Generation.

    Science.gov (United States)

    Zhang, Kun; Liu, Yu; Wang, Yuning; Zhang, Ren; Liu, Jiangang; Wei, Jia; Qian, Hufei; Qian, Kun; Chen, Ruoping; Liu, Baohong

    2018-05-09

    Reliable profiling of the extracellular dopamine (DA) concentration in the central nervous system is essential for a deep understanding of its biological and pathological functions. However, quantitative determination of this neurotransmitter remains a challenge because of the extremely low concentration of DA in the cerebrospinal fluid (CSF) of patients. Herein, on the basis of the specific recognition of boronate toward diol and N-hydroxysuccinimide ester toward the amine group, a simple and highly sensitive strategy was presented for DA detection by using surface-enhanced Raman scattering (SERS) spectroscopy as a signal readout. This was realized by first immobilizing 3,3'-dithiodipropionic acid di( N-hydroxysuccinimide ester) on gold thin film surfaces to capture DA, followed by introducing 3-mercaptophenylboronic acid (3-MPBA)-functionalized silver nanoparticles to generate numerous plasmonic "hot spots" with the nanoparticle-on-mirror geometry. Such a dual-recognition mechanism not only avoids complicated bioelement-based manipulations but also efficiently decreases the background signal. With the direct use of the recognition probe 3-MPBA as a Raman reporter, the "signal-on" SERS method was employed to quantify the concentration of DA from 1 pM to 1 μM with a detection limit of 0.3 pM. Moreover, our dual-recognition-directed SERS assay exhibited a high resistance to cerebral interference and was successfully applied to monitoring of DA in CSF samples of patients.

  13. CMOS monolithic active pixel sensors for high energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Snoeys, W., E-mail: walter.snoeys@cern.ch

    2014-11-21

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon are only now starting to make their way into high energy physics. Two major requirements are radiation tolerance and low power consumption. For the most extreme radiation levels, signal charge has to be collected by drift from a depletion layer onto a designated collection electrode without losing the signal charge elsewhere in the in-pixel circuit. Low power consumption requires an optimization of Q/C, the ratio of the collected signal charge over the input capacitance [1]. Some solutions to combine sufficient Q/C and collection by drift require exotic fabrication steps. More conventional solutions up to now require a simple in-pixel readout circuit. Both high voltage CMOS technologies and Monolithic Active Pixel Sensors (MAPS) technologies with high resistivity epitaxial layers offer high voltage diodes. The choice between the two is not fundamental but more a question of how much depletion can be reached and also of availability and cost. This paper tries to give an overview.

  14. Expanding Applications of SERS through Versatile Nanomaterials Engineering (Postprint)

    Science.gov (United States)

    2017-06-22

    which form covalent metal–S bonds), amine, cyanide , and carboxylic acid functional groups; and their adsorption depends on solution pH and ionic...for some SERS sensing appli- cations, such as biosensing in complex biological fluids (where multiple molecules with primary amine and carboxylic acid...bonding interactions.33d,e Furthermore, mixed SAMs can take advantage of multiple types of interactions and build complexity into the surface chemistry

  15. Significado de ser docente para el adulto mayor sanfernandino

    OpenAIRE

    Martina, Martha; Santos, Gladys; Lema, Julia

    2013-01-01

    Objetivos: Comprender el significado de ser docente para el adulto mayor de la Facultad de Medicina de San Marcos y describir las motivaciones que determinan, de alguna forma, su decisión de postergar su retiro, no obstante haber cumplido con los requisitos legales para la jubilación. Diseño: Estudio de caso cualitativo. Institución: Facultad de Medicina, UNMSM. Participantes: Docentes adulto mayores de la Facultad de Medicina. Intervenciones: Entrevista a profundidad. Principales medidas de ...

  16. The BARD1 Cys557Ser variant and breast cancer risk in Iceland.

    Directory of Open Access Journals (Sweden)

    Simon N Stacey

    2006-07-01

    Full Text Available Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer.The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11-3.01, p = 0.014. The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22-4.75, p = 0.015. Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16-8.40, p = 0.046 in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We found that an excess of ancestors

  17. Management of spent high activity radioactive sources (SHARS)

    International Nuclear Information System (INIS)

    2002-09-01

    The objective of this report is to provide all people involved in the handling and management of high activity sources with sufficient information about processes that are required for the safe management of spent high activity radioactive sources (SHARS). This includes examples of spent source management that are already taking place and also a description of the range of appropriate options that are available for each stage in the management process. This report also aims to identify the important issues to be addressed in order to develop a waste management strategy as part of the integrated management strategy that takes account of international experience and the guidance and principles that have been learned from that experience. This report relates specifically to SHARS, which are spent sources that have the potential, with short exposures, to produce acute health effects if handled incorrectly. In addition, they may also incur significant economic costs in any retrieval or environmental remediation operation, following loss of or damage to such a source. The report provides guidance on the technical, administrative and economic issues associated with SHARS from the moment they cease to be in use through to disposal, including temporary storage, transport, conditioning and interim storage

  18. Activated polyaniline-based carbon nanoparticles for high performance supercapacitors

    International Nuclear Information System (INIS)

    Zhou, Jin; Zhu, Tingting; Xing, Wei; Li, Zhaohui; Shen, Honglong; Zhuo, Shuping

    2015-01-01

    Polyaniline (PANI) nanoparticles have been prepared by disperse polymerization of aniline in the presence of poly(4-styrenesulfonate). The PANI nanoparticles are further subjected to pyrolysis treatment and chemical-activation to prepare the activated nitrogen-doped carbon nanoparticles (APCNs). The porosity, structure and nitrogen-doped surface chemistry are analyzed by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, X-ray diffraction and X-ray photoelectron spectroscopy. The capacitive performance of the APCNs materials are test in 6 M KOH electrolyte. Benefitting from the abundant micropores with short length, large specific surface area, hierarchical porosity and heteroatom-doped polar pore surface, the APCNs materials exhibit v exhibit very high specific capacitance up to 341 F g −1 , remarkable power capability and excellent long-term cyclic stability (96.6% after 10 000 cycles). At 40 A g −1 , APCN-2 carbon shows a capacitance of 164 F g −1 , responding to a high energy and power densities of 5.7 Wh kg −1 and 10 000 W kg −1

  19. Control of high frequency microactuators using active structures

    International Nuclear Information System (INIS)

    Kreth, P A; Alvi, F S; Reese, B M; Oates, W S

    2015-01-01

    A fluidically driven microactuator that generates supersonic, pulsed microjets has been implemented with smart materials to actively and precisely control the frequency of the microjets in a closed-loop manner. Since this actuator relies on a number of microscale flow and acoustic phenomena to produce the pulsed microjets, its resonant frequency is determined by its geometry and other flow parameters. The design discussed in this paper integrates piezoelectric stacks by connecting them to movable sidewalls within the actuator such that the microactuator's internal geometry can be controlled by varying the voltage across the piezo-stacks. An open-loop control scheme demonstrates the frequency modulation capabilities that are enabled with this design: very large frequency deviations (up to ±500 Hz) around the actuator design frequency are attained at very high rates (up to 1 kHz). Closed-loop control of the microactuator's frequency was also demonstrated, and the results indicate that (combined with appropriate sensors) this actuator could be used effectively for active, feedback control in high-speed, resonance-dominated flowfields. This proof of concept study clearly illustrates the ability of this robust and compact actuator to produce perturbations that can be modulated and controlled based on the desired control objective. (paper)

  20. Development of High Performance CFRP/Metal Active Laminates

    Science.gov (United States)

    Asanuma, Hiroshi; Haga, Osamu; Imori, Masataka

    This paper describes development of high performance CFRP/metal active laminates mainly by investigating the kind and thickness of the metal. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature.

  1. High Income Inequality as a Structural Factor in Entrepreneurial Activity

    Directory of Open Access Journals (Sweden)

    Antonio Lecuna

    2014-04-01

    Full Text Available Statistical tests on a panel of data from 54 countries over the 2004–2009 period support the proposition that high income inequality and entrepreneurial activity share a positive linear relationship. In a novel approach, the dependent variable is defined from two independent and uncorrelated perspectives: (1 the World Bank Group Entrepreneurship Snapshot, which measures new business entry density based on secondary official sources; and (2 the Total Early Stage Entrepreneurial Activity of the Global Entrepreneurship Monitor project, which is a survey-based measure of formal and informal entrepreneurial participation rates. The empirical strategy is based on the logic that economies with increasing concentrations of wealth tend to encourage entrepreneurial activity because entrepreneurs accumulate more income than workers. Following the disequalizing model, once this inequality appears, it is reinforced in successive generations. The intuition behind this outcome is that a certain level of initial capital is required to establish a new enterprise, which implies that the probability of becoming an entrepreneur increases if an individual has inherited wealth.

  2. Laser in medicine Láser en medicina

    Directory of Open Access Journals (Sweden)

    Juan C. Cárdenas

    1993-03-01

    Full Text Available The fundamentals of laser functioning and a brief historic description on the subject are presented; laser Is classified according to emission potency, materials with which it is built and pulsation. Different mechanisms of action of laser as well as Its indications and contraindications are discussed. Emphasis is given to low-power laser. Local and foreign experiences with Its medlcal use are briefly described

    Se revisan los principios fundamentales del funcionamiento del láser, se hace una breve revisión histórica del mismo y se lo clasifica de acuerdo con la potencia de emisión, los materiales de fabricación y la pulsación. Se enumeran los diferentes mecanismos de acción del láser y sus indicaciones y contraindicaciones haciendo énfasis en lo concerniente al láser de baja potencia, tanto pulsado como no pulsado; se alude a las experiencias nacionales y de otros países.

  3. Solution-dispersible Au nanocube dimers with greatly enhanced two-photon luminescence and SERS

    Science.gov (United States)

    Liu, Xiao-Li; Liang, Shan; Nan, Fan; Yang, Zhong-Jian; Yu, Xue-Feng; Zhou, Li; Hao, Zhong-Hua; Wang, Qu-Quan

    2013-05-01

    We report the synthesis of 43-nm diameter Au nanocube dimers by using Ag+ ions as competitive ligands to freeze l-cysteine-induced assembly process of the nanocubes to a desirable stage. Ascribed to the resonant interparticle coupling with an newly arising plasmon band at 710 nm and local field enhancement, the two-photon luminescence intensity of the Au nanocube dimers in solution was over 20 times stronger than that of the monomers in the wavelength range 555-620 nm. Furthermore, by coupling Raman tags onto the nanocube surface, a solution-based surface-enhanced Raman scattering (SERS) of the nanocube dimers had an enhancement factor of over 10 times compared to the isolated nanocubes. To sum up, with high stability in solution and attractive optical properties, the Au nanocube dimers have potential applications in in vivo bio-imaging and solution-based SERS.We report the synthesis of 43-nm diameter Au nanocube dimers by using Ag+ ions as competitive ligands to freeze l-cysteine-induced assembly process of the nanocubes to a desirable stage. Ascribed to the resonant interparticle coupling with an newly arising plasmon band at 710 nm and local field enhancement, the two-photon luminescence intensity of the Au nanocube dimers in solution was over 20 times stronger than that of the monomers in the wavelength range 555-620 nm. Furthermore, by coupling Raman tags onto the nanocube surface, a solution-based surface-enhanced Raman scattering (SERS) of the nanocube dimers had an enhancement factor of over 10 times compared to the isolated nanocubes. To sum up, with high stability in solution and attractive optical properties, the Au nanocube dimers have potential applications in in vivo bio-imaging and solution-based SERS. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01170d

  4. The calcium-dependent protein kinase RcCDPK2 phosphorylates sucrose synthase at Ser11 in developing castor oil seeds.

    Science.gov (United States)

    Fedosejevs, Eric T; Gerdis, Suzanne A; Ying, Sheng; Pyc, Michal; Anderson, Erin M; Snedden, Wayne A; Mullen, Robert T; She, Yi-Min; Plaxton, William C

    2016-10-15

    Imported sucrose is cleaved by sucrose synthase (SUS) as a critical initial reaction in the biosynthesis of storage end-products by developing seeds. Although SUS is phosphorylated at a conserved seryl residue by an apparent CDPK (Ca 2+ -dependent protein kinase) in diverse plant tissues, the functions and mechanistic details of this process remain obscure. Thus, the native CDPK that phosphorylates RcSUS1 (Ricinus communis SUS1) at Ser 11 in developing COS (castor oil seeds) was highly purified and identified as RcCDPK2 by MS/MS. Purified RcSUS1-K (-kinase) and heterologously expressed RcCDPK2 catalyzed Ca 2+ -dependent Ser 11 phosphorylation of RcSUS1 and its corresponding dephosphopeptide, while exhibiting a high affinity for free Ca 2+ ions [K 0.5 (Ca 2+ ) < 0.4 µM]. RcSUS1-K activity, RcCDPK2 expression, and RcSUS1 Ser 11 phosphorylation peaked during early COS development and then declined in parallel. The elimination of sucrose import via fruit excision triggered RcSUS1 dephosphorylation but did not alter RcSUS1-K activity, suggesting a link between sucrose signaling and posttranslational RcCDPK2 control. Both RcCDPK2-mCherry and RcSUS1-EYFP co-localized throughout the cytosol when transiently co-expressed in tobacco suspension cells, although RcCDPK2-mCherry was also partially localized to the nucleus. Subcellular fractionation revealed that ∼20% of RcSUS1-K activity associates with microsomal membranes in developing COS, as does RcSUS1. In contrast with RcCDPK1, which catalyzes inhibitory phosphorylation of COS bacterial-type phosphoenolpyruvate carboxylase at Ser 451 , RcCDPK2 exhibited broad substrate specificity, a wide pH-activity profile centered at pH 8.5, and insensitivity to metabolite effectors or thiol redox status. Our combined results indicate a possible link between cytosolic Ca 2+ -signaling and the control of photosynthate partitioning during COS development. © 2016 The Author(s); published by Portland Press Limited on behalf of the

  5. Multi-branched gold nanostars with fractal structure for SERS detection of the pesticide thiram

    Science.gov (United States)

    Zhu, Jian; Liu, Mei-Jin; Li, Jian-Jun; Li, Xin; Zhao, Jun-Wu

    2018-01-01

    The surface-enhanced Raman scattering (SERS) activity of multi-branched gold nanostars with fractal structure has been investigated for trace detection of pesticide thiram. Raman spectrum results show that the gold nanostars substrate can produce about 102 fold stronger signal than the thiram alone with the thiram concentration increase of 103 times and 1.4 fold stronger signal than the gold nanostars without fractal feature. In the detection procedure, the most prominent SERS peak at 1376 cm- 1 has been chosen to characterize and quantify the concentration of thiram. Experimental results indicate this Raman substrate based on fractal gold nanostars exhibits excellent selective probing performance for thiram with a detection limit as low as 10- 10 M in solution and 0.24 ng/cm2 in apple peels. Interference experiment results show that the effects from the interfering pesticides could be neglected in the detection procedure. Therefore, the gold nanostars as a SERS substrate have excellent sensitivity and selectivity.

  6. SERS and DFT study of copper surfaces coated with corrosion inhibitor

    Directory of Open Access Journals (Sweden)

    Maurizio Muniz-Miranda

    2014-12-01

    Full Text Available Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT approach.

  7. Silver-gelatine bionanocomposites for qualitative detection of a pesticide by SERS.

    Science.gov (United States)

    Fateixa, S; Soares, S F; Daniel-da-Silva, A L; Nogueira, H I S; Trindade, T

    2015-03-07

    The controlled release of pesticides using hydrogel vehicles is an important procedure to limit the amount of these compounds in the environment, providing an effective way for crop protection. A key-step in the formulation of new materials for these purposes encompasses the monitoring of available pesticides in the gel matrix under variable working conditions. In this work, we report a series of bionanocomposites made of Ag nanoparticles (NPs) and gelatine A for the surface enhanced Raman scattering (SERS) detection of sodium diethyldithiocarbamate (EtDTC) as a pesticide model. These studies demonstrate the effectiveness of these substrates for the detection of EtDTC in aqueous solutions in a concentration as low as 10(-5) M. We have monitored the Raman signal enhancement of this analyte in bionanocomposites having an increasing amount of gelatine due to their relevance in formulating hydrogels of variable gel strengths. Under these conditions, the bionanocomposites have shown an effective SERS activity using EtDTC, demonstrating their effectiveness in the qualitative detection of this analyte. Finally, experiments involving the release of EtDTC from Ag/gelatine samples have been monitored by SERS, which attest the potential of this spectroscopic method in the laboratorial monitoring of hydrogels for pesticide release.

  8. Production of high-specific activity radionuclides using SM high-flux reactor

    International Nuclear Information System (INIS)

    Karelin, Ye.A.; Toporov, Yu.G.; Filimonov, V.T.; Vakhetov, F.Z.; Tarasov, V.A.; Kuznetsov, R.A.; Lebedev, V.M.; Andreev, O.I.; Melnik, M.I.; Gavrilov, V.D.

    1997-01-01

    The development of High Specific Activity (HSA) radionuclides production technologies is one of the directions of RIAR activity, and the high flux research reactor SM, having neutron flux density up to 2.10 15 cm -2 s 1 in a wide range of neutron spectra hardness, plays the principal role in this development. The use of a high-flux reactor for radionuclide production provides the following advantages: production of radionuclides with extremely high specific activity, decreasing of impurities content in irradiated targets (both radioactive and non-radioactive), cost-effective use of expensive isotopically enriched target materials. The production technologies of P-33, Gd-153, W-188, Ni-63, Fe-55,59, Sn-113,117m,119m, Sr- 89, applied in industry, nuclear medicine, research, etc, were developed by RIAR during the last 5-10 years. The research work included the development of calculation procedures for radionuclide reactor accumulation forecast, experimental determination of neutron cross-sections, the development of irradiated materials reprocessing procedures, isolation and purification of radionuclides. The principal results are reviewed in the paper. (authors)

  9. High-frequency TRNS reduces BOLD activity during visuomotor learning.

    Directory of Open Access Journals (Sweden)

    Catarina Saiote

    Full Text Available Transcranial direct current stimulation (tDCS and transcranial random noise stimulation (tRNS consist in the application of electrical current of small intensity through the scalp, able to modulate perceptual and motor learning, probably by changing brain excitability. We investigated the effects of these transcranial electrical stimulation techniques in the early and later stages of visuomotor learning, as well as associated brain activity changes using functional magnetic resonance imaging (fMRI. We applied anodal and cathodal tDCS, low-frequency and high-frequency tRNS (lf-tRNS, 0.1-100 Hz; hf-tRNS 101-640 Hz, respectively and sham stimulation over the primary motor cortex (M1 during the first 10 minutes of a visuomotor learning paradigm and measured performance changes for 20 minutes after stimulation ceased. Functional imaging scans were acquired throughout the whole experiment. Cathodal tDCS and hf-tRNS showed a tendency to improve and lf-tRNS to hinder early learning during stimulation, an effect that remained for 20 minutes after cessation of stimulation in the late learning phase. Motor learning-related activity decreased in several regions as reported previously, however, there was no significant modulation of brain activity by tDCS. In opposition to this, hf-tRNS was associated with reduced motor task-related-activity bilaterally in the frontal cortex and precuneous, probably due to interaction with ongoing neuronal oscillations. This result highlights the potential of lf-tRNS and hf-tRNS to differentially modulate visuomotor learning and advances our knowledge on neuroplasticity induction approaches combined with functional imaging methods.

  10. Porous plasmonic nanocomposites for SERS substrates fabricated by two-step laser method

    Energy Technology Data Exchange (ETDEWEB)

    Koleva, M.E., E-mail: mihaela_ek@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan); Nedyalkov, N.N.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); Gerlach, J.W.; Hirsch, D.; Prager, A.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, D-04318 Leipzig (Germany); Fukata, N.; Jevasuwan, W. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan)

    2016-04-25

    This research is focused on investigation of coupled plasmonic/metal-semiconductor nanomaterials. A two-step laser-assisted method is demonstrated for formation of plasmonic Ag nanoparticles (NPs) distributed into porous metal–oxide semiconductors. The mosaic Ag-ZnO target is used for laser ablation and, subsequently, laser annealing of the deposited layer is applied. The plasmon resonance properties of the nanostructures produced are confirmed by optical transmission spectroscopy. The wurtzite structure of ZnO is formed with tilted c-axis orientation and, respectively, a mixed Raman mode appears at 580 cm{sup −1}. The oxygen pressure applied during a deposition process has impact on the morphology and thickness of the porous nanostructures, but not on the size and size distribution of AgNPs. The porous nanocomposites exhibited potential for SERS applications, most pronounced for the oxygen deficient sample, grown at lower oxygen pressure. The observed considerable SERS enhancement of R6G molecules on AgNP/ZnO can be attributed to the ZnO-to-molecule charge transfer contribution, enhanced by the additional electrons from the local surface plasmon resonance (LSPR) of AgNPs to the ZnO through the conduction band. - Highlights: • Porous AgNPs/ZnO composites are obtained by laser deposition and laser annealing. • Morphology and properties depend on growth oxygen pressure. • The emergence of mixed-symmetry Raman mode at 580 cm{sup −1} is registered. • The AgNPs/ZnO porous nanocomposites are suitable for SERS-active substrates. • The charge transfer enhanced by LSPR has a contribution to SERS effect.

  11. Comparison of physical activities of female football players in junior high school and high school.

    Science.gov (United States)

    Inoue, Yuri; Otani, Yoshitaka; Takemasa, Seiichi

    2017-08-01

    [Purpose] This study aimed to compare physical activities between junior high school and high school female football players in order to explain the factors that predispose to a higher incidence of sports injuries in high school female football players. [Subjects and Methods] Twenty-nine female football players participated. Finger floor distance, the center of pressure during single limb stance with eyes open and closed, the 40-m linear sprint time, hip abduction and extension muscle strength and isokinetic knee flexion and extension peak torque were measured. The modified Star Excursion Balance Test, the three-steps bounding test and three-steps hopping tests, agility test 1 (Step 50), agility test 2 (Forward run), curl-up test for 30 seconds and the Yo-Yo intermittent recovery test were performed. [Results] The high school group was only significantly faster than the junior high school group in the 40-m linear sprint time and in the agility tests. The distance of the bounding test in the high school group was longer than that in the junior high school group. [Conclusion] Agility and speed increase with growth; however, muscle strength and balance do not develop alongside. This unbalanced development may cause a higher incidence of sports injuries in high school football players.

  12. Designing messages with high sensation value: when activation meets reactance.

    Science.gov (United States)

    Xu, Jie

    2015-01-01

    Based on two theoretical models--activation model of information exposure and psychological reactance theory--this study examined the individual and combined effects of message sensation value (MSV) and controlling language on young adults' information processing. Two experimental studies on anti-drunken driving and anti-smoking public service announcements were conducted that were conceptual replications of one another. The measures included perceived threat to freedom, sensation seeking, perceived ad effectiveness and state reactance (anger). Across the two studies, MSV was found to advance the perceived ad effectiveness, and controlling language contributed to anger. A consistent interaction was revealed, such that participants responded positively to the high sensation value messages when presented with low controlling language. The effect of high sensation value anti-smoking ads to advance persuasiveness particularly under the condition of low controlling language was more influential to low sensation seekers. This study suggests that increasing MSV coupled with high controlling language can backfire, especially when targeting young adults. The implications for persuasion in general are considered, as well as the specific findings for drunken driving and smoking.

  13. Functional paper-based SERS substrate for rapid and sensitive detection of Sudan dyes in herbal medicine

    Science.gov (United States)

    Wu, Mianmian; Li, Pan; Zhu, Qingxia; Wu, Meiran; Li, Hao; Lu, Feng

    2018-05-01

    There has been an increasing demand for rapid and sensitive techniques for the identification of Sudan compounds that emerged as the most often illegally added fat-soluble dyes in herbal medicine. In this report, we have designed and fabricated a functionalized filter paper consisting of gold nanorods (GNRs) and mono-6-thio-cyclodextrin (HS-β-CD) as a surface-enhanced Raman spectroscopy (SERS) substrate, in which the GNR provides sufficient SERS enhancement, and the HS-β-CD with strong chemical affinity toward GNR provides the inclusion compound to capture hydrophobic molecules. Moreover, the CD-GNR were uniformly assembled on filter paper cellulose through the electrostatic adsorption and hydrogen bond, so that the CD-GNR paper-based SERS substrate (CD-GNR-paper) demonstrated higher sensitivity for the determination of Sudan III (0.1 μM) and Sudan IV (0.5 μM) than GNRs paper-based SERS substrate (GNR-paper), with high stability after the storage in the open air for 90 days. Importantly, CD-GNR-paper can effectively collect the Sudan dyes from illegally adulterated onto samples of Resina Draconis with a simple operation, further open up new exciting opportunity for SERS detection of more compounds illegally added with high sensitivity and fast signal responses.

  14. Leucipo, Demócrito e Kant: uma Reflexão sobre a Equivalência entre Ser e Não-Ser

    Directory of Open Access Journals (Sweden)

    Eberth Eleuterio dos Santos

    2015-08-01

    Full Text Available De início, apresentaremos a tese de Demócrito e Leucipo, segundo a qual o ser não é mais que o não-ser, tendo como contraponto o pensamento eleata acerca da inexistência necessária do não-ser. Esta discussão nos remete à oposição entre o pleno (cheio e o vazio que será posteriormente traduzida na oposição entre o ser e o nada (ou o não-ser. Desse modo, a oposição entre o pleno e o vazio é uma oposição que se desloca para o ser e o não-ser. Em seguida, faremos a apreciação do escrito pré-crítico kantiano Ensaio para introduzir em filosofia o conceito de grandeza negativa, no qual distinguimos certo tipo de oposição tomada entre grandezas em geral que, acreditamos, poderia ser interpretado como estando de acordo com o posicionamento de Demócrito e Leucipo sobre o estatuto ontológico do não-ser como princípio equivalente ao ser, e não como sua contradição em sentido puramente lógico.

  15. 3D TiO2 submicrostructures decorated by silver nanoparticles as SERS substrate for organic pollutants detection and degradation

    International Nuclear Information System (INIS)

    Chen, Jianjun; Su, Huilan; You, Xueling; Gao, Jing; Lau, Woon Ming; Zhang, Di

    2014-01-01

    Graphical abstract: - Highlights: • Contrive a multifunctional SERS substrate with 3D sub-micrometer structure and multicomponent. • The blue wing of butterfly (Euploea mulciber) is used as template for Ag/TiO 2 nanocomposites. • The 3D submicrostructures Ag/TiO 2 presents superior SERS effect and photocatalytic activity. • Pave a facile route to prepare multifunctional material by utilizing smart structural designs in nature. - Abstract: The blue wing of butterfly Euploea mulciber is used as a template to generate Ag/TiO 2 nanocomposites. Thereinto, Ag nanoparticles are deposited uniformly onto TiO 2 substrate with three dimensional (3D) submicrometer structures. This unique 3D sub-micrometer structures featured with ridges, ribs and struts can provide a large number of active “hot spots” for enhanced Raman signal. Meanwhile, depositing Ag onto the TiO 2 surface can greatly boost its SERS effect and photocatalytic activity by bringing additional electrons into the molecules and inhibiting electrons–holes recombination. Thus, the as-prepared 3D Ag/TiO 2 submicrostructures can not only offer sensitive and reproducible SERS signals, but also present superior photocatalytic activity, which can be utilized to detect and eliminate organic pollutants

  16. Smart SERS Hot Spots: Single Molecules Can Be Positioned in a Plasmonic Nanojunction Using Host-Guest Chemistry.

    Science.gov (United States)

    Kim, Nam Hoon; Hwang, Wooseup; Baek, Kangkyun; Rohman, Md Rumum; Kim, Jeehong; Kim, Hyun Woo; Mun, Jungho; Lee, So Young; Yun, Gyeongwon; Murray, James; Ha, Ji Won; Rho, Junsuk; Moskovits, Martin; Kim, Kimoon

    2018-04-04

    Single-molecule surface-enhanced Raman spectroscopy (SERS) offers new opportunities for exploring the complex chemical and biological processes that cannot be easily probed using ensemble techniques. However, the ability to place the single molecule of interest reliably within a hot spot, to enable its analysis at the single-molecule level, remains challenging. Here we describe a novel strategy for locating and securing a single target analyte in a SERS hot spot at a plasmonic nanojunction. The "smart" hot spot was generated by employing a thiol-functionalized cucurbit[6]uril (CB[6]) as a molecular spacer linking a silver nanoparticle to a metal substrate. This approach also permits one to study molecules chemically reluctant to enter the hot spot, by conjugating them to a moiety, such as spermine, that has a high affinity for CB[6]. The hot spot can accommodate at most a few, and often only a single, analyte molecule. Bianalyte experiments revealed that one can reproducibly treat the SERS substrate such that 96% of the hot spots contain a single analyte molecule. Furthermore, by utilizing a series of molecules each consisting of spermine bound to perylene bisimide, a bright SERS molecule, with polymethylene linkers of varying lengths, the SERS intensity as a function of distance from the center of the hot spot could be measured. The SERS enhancement was found to decrease as 1 over the square of the distance from the center of the hot spot, and the single-molecule SERS cross sections were found to increase with AgNP diameter.

  17. SERS and fluorescence-based ultrasensitive detection of mercury in water.

    Science.gov (United States)

    Makam, Pandeeswar; Shilpa, Rohilla; Kandjani, Ahmad Esmaielzadeh; Periasamy, Selvakannan R; Sabri, Ylias Mohammad; Madhu, Chilakapati; Bhargava, Suresh Kumar; Govindaraju, Thimmaiah

    2018-02-15

    The development of reliable and ultrasensitive detection marker for mercury ions (Hg 2+ ) in drinking water is of great interest for toxicology assessment, environmental protection and human health. Although many Hg 2+ detection methods have been developed, only few offer sensitivities below 1pM. Herein, we describe a simple histidine (H) conjugated perylene diimide (PDI) bolaamphiphile (HPH) as a dual-responsive optical marker to develop highly selective and sensitive probe as visible (sol-to-gel transformation), fluorescence and SERS-based Hg 2+ sensor platform in the water. Remarkably, HPH as a SERS marker supported on Au deposited monodispersed nanospheres monolayers (Au-MNM) of polystyrene offers an unprecedented selectivity and the best ever reported detection limit (LOD) of 60 attomolar (aM, 0.01 parts-per-quadrillion (ppq)) for Hg 2+ in water. This is ten orders of magnitude lower than the United States Environmental Protection Agency (USEPA) tolerance limit of Hg 2+ in drinking water (10nM, 2 ppb). This simple and effective design principle of host-guest interactions driven fluorescence and SERS-based detection may inspire the future molecular engineering strategies for the development of ultrasensitive toxic analyte sensor platforms. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Two-step fabrication of nanoporous copper films with tunable morphology for SERS application

    Science.gov (United States)

    Diao, Fangyuan; Xiao, Xinxin; Luo, Bing; Sun, Hui; Ding, Fei; Ci, Lijie; Si, Pengchao

    2018-01-01

    It is important to design and fabricate nanoporous metals (NPMs) with optimized microstructures for specific applications. In this contribution, nanoporous coppers (NPCs) with controllable thicknesses and pore sizes were fabricated via the combination of a co-sputtering of Cu/Ti with a subsequent dealloying process. The effect of dealloying time on porous morphology and the corresponding surface enhanced Raman scattering (SERS) behaviors were systematically investigated. Transmission electron microscopy (TEM) identified the presences of the gaps formed between ligaments and also the nanobumps on the nanoparticle-aggregated ligament surface, which were likely to contribute as the ;hot spots; for electromagnetic enhancement. The optimal NPC film exhibited excellent SERS performance towards Rhodamine 6G (R6G) with a low limiting detection (10-9 M), along with good uniformity and reproducibility. The calculated enhancement factor of ca. 4.71 × 107 was over Au substrates and comparable to Ag systems, promising the proposed NPC as a cheap candidate for high-performance SERS substrate.

  19. SERS-Fluorescence Dual-Mode pH-Sensing Method Based on Janus Microparticles.

    Science.gov (United States)

    Yue, Shuai; Sun, Xiaoting; Wang, Ning; Wang, Yaning; Wang, Yue; Xu, Zhangrun; Chen, Mingli; Wang, Jianhua

    2017-11-15

    A surface-enhanced Raman scattering (SERS)-fluorescence dual-mode pH-sensing method based on Janus microgels was developed, which combined the advantages of high specificity offered by SERS and fast imaging afforded by fluorescence. Dual-mode probes, pH-dependent 4-mercaptobenzoic acid, and carbon dots were individually encapsulated in the independent hemispheres of Janus microparticles fabricated via a centrifugal microfluidic chip. On the basis of the obvious volumetric change of hydrogels in different pHs, the Janus microparticles were successfully applied for sensitive and reliable pH measurement from 1.0 to 8.0, and the two hemispheres showed no obvious interference. The proposed method addressed the limitation that sole use of the SERS-based pH sensing usually failed in strong acidic media. The gastric juice pH and extracellular pH change were measured separately in vitro using the Janus microparticles, which confirmed the validity of microgels for pH sensing. The microparticles exhibited good stability, reversibility, biocompatibility, and ideal semipermeability for avoiding protein contamination, and they have the potential to be implantable sensors to continuously monitor pH in vivo.

  20. VTEC behavior in the American sector during high solar activity

    CERN Document Server

    Ezquer, R G; Brunini, C; Conicet; Meza, A; Mosert, M; Radicella, S M

    2002-01-01

    The behavior of the vertical total electron content (VTEC) obtained from GPS signals received during the high solar activity year 1999 at stations placed in the American sector, is reported. The considered latitude range extends from 18.4 to -64.7 and the longitude ranges from 281.3 to 297.7. Median, lower and upper quartiles are used to specify variability, because they have the advantage of being less affected by large deviations that can occur during magnetic storms. The results show that the VTEC values corresponding to equinox are greater than those of solstice and that, the highest VTEC values are observed at low latitude stations. In general, the variability during daylight hours is about 30% of median or less, and that observed for nighttime hours is greater than the mentioned percentage, particularly at last hours of the night near the northern peak of the equatorial anomaly.

  1. A Case of Hyperammonemia Associated with High Dihydropyrimidine Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Keiki Nagaharu

    2016-01-01

    Full Text Available Over the past decades, 5-Fluorouracil (5-FU has been widely used to treat several types of carcinoma, including esophageal squamous cell carcinoma. In addition to its common side effects, including diarrhea, mucositis, neutropenia, and anemia, 5-FU treatment has also been reported to cause hyperammonemia. However, the exact mechanism responsible for 5-FU-induced hyperammonemia remains unknown. We encountered an esophageal carcinoma patient who developed hyperammonemia when receiving 5-FU-containing chemotherapy but did not exhibit any of the other common adverse effects of 5-FU treatment. At the onset of hyperammonemia, laboratory tests revealed high dihydropyrimidine dehydrogenase (DPD activity and rapid 5-FU clearance. Our findings suggested that 5-FU hypermetabolism may be one of the key mechanisms responsible for hyperammonemia during 5-FU treatment.

  2. VTEC behavior in the American sector during high solar activity

    International Nuclear Information System (INIS)

    Ezquer, R.G.; Brunini, C.; Meza, A.; Azpilicueta, F.; Mosert, M.; Radicella, S.M.

    2003-01-01

    The behavior of the vertical total electron content (VTEC) obtained from GPS signals received during the high solar activity year 1999 at stations placed in the American sector, is reported. The considered latitude range extends from 18.4 to -64.7 and the longitude ranges from 281.3 to 297.7. Median, lower and upper quartiles are used to specify variability, because they have the advantage of being less affected by large deviations that can occur during magnetic storms. The results show that the VTEC values corresponding to equinox are greater than those of solstice and that, the highest VTEC values are observed at low latitude stations. In general, the variability during daylight hours is about 30% of median or less, and that observed for nighttime hours is greater than the mentioned percentage, particularly at last hours of the night near the northern peak of the equatorial anomaly. (author)

  3. Active optics: off axis aspherics generation for high contrast imaging

    Science.gov (United States)

    Hugot, E.; Laslandes, M.; Ferrari, M.; Vives, S.; Moindrot, S.; El Hadi, K.; Dohlen, K.

    2017-11-01

    Active Optics methods, based on elasticity theory, allow the aspherisation of optical surfaces by stress polishing but also active aspherisation in situ. Researches in this field will impact the final performance and the final cost of any telescope or instrument. The stress polishing method is well suited for the superpolishing of aspheric components for astronomy. Its principle relies on spherical polishing with a full-sized tool of a warped substrate, which becomes aspherical once unwarped. The main advantage of this technique is the very high optical quality obtained either on form or on high spatial frequency errors. Furthermore, the roughness can be decreased down to a few angstroms, thanks the classical polishing with a large pitch tool, providing a substantial gain on the final scientific performance, for instance on the contrast on coronagraphic images, but also on the polishing time and cost. Stress polishing is based on elasticity theory, and requires an optimised deformation system able to provide the right aspherical form on the optical surface during polishing. The optical quality of the deformation is validated using extensive Finite Element Analysis, allowing an estimation of residuals and an optimisation of the warping harness. We describe here the work realised on stress polishing of toric mirrors for VLT-SPHERE and then our actual work on off axis aspherics (OAA) for the ASPIICS-Proba3 mission for solar coronagraphy. The ASPIICS optical design made by Vives et al is a three mirrors anastigmat including a concave off axis hyperboloid and a convex off axis parabola (OAP). We are developing a prototype in order to demonstrate the feasibility of this type of surface, using a multi-mode warping harness (Lemaitre et al). Furthermore, we present our work on variable OAP, meaning the possibility to adjust the shape of a simple OAP in situ with a minimal number of actuators, typically one actuator per optical mode (Focus, Coma and Astigmatism

  4. Development plan. High activity-long living wastes project. Abstract

    International Nuclear Information System (INIS)

    2007-01-01

    This brochure presents the actions that the ANDRA (the French national agency of radioactive wastes) has to implement in the framework of the project of high activity-long living (HALL) radioactive wastes (HAVL project) conformably to the requirements of the program defined in the law from June 28, 2006 (law no 2006-739). This law precises the three, complementary, research paths to explore for the management of this type of wastes: separation and transmutation of long-living radioactive elements, reversible disposal in deep geologic underground, and long duration storage. The ANDRA's action concerns the geologic disposal aspect. The following points are presented: the HALL wastes and their containers, the reversible disposal procedure, the HAVL project: financing of researches, storage concepts, development plan of the project (dynamics, information and dialogue approach, input data, main steps, schedule); the nine programs of the HAVL project (laboratory experiments and demonstration tests, surface survey, scientific program, simulation program, surface engineering studies and technological tests, information and communication program, program of environment and facilities surface observation and monitoring, waste packages management, monitoring and transport program, disposal program); the five transverse technical and scientific activities (safety, reversibility, cost, health and occupational safety, impact study). (J.S.)

  5. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  6. High matrix metalloproteinase activity is a hallmark of periapical granulomas.

    Science.gov (United States)

    de Paula-Silva, Francisco Wanderley Garcia; D'Silva, Nisha J; da Silva, Léa Assed Bezerra; Kapila, Yvonne Lorraine

    2009-09-01

    The inability to distinguish periapical cysts from granulomas before performing root canal treatment leads to uncertainty in treatment outcomes because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Because matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed by using one-way analysis of variance followed by the Tukey test. We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the MMP family. Compared with cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs) in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared with cysts. Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas unlike periapical cysts.

  7. The Role of the PGC1α Gly482Ser Polymorphism in Weight Gain due to Intensive Diabetes Therapy

    Directory of Open Access Journals (Sweden)

    Samir S. Deeb

    2009-01-01

    Full Text Available The Diabetes Control and Complications Trial (DCCT involved intensive diabetes therapy of subjects with type 1 diabetes mellitus (T1DM for an average period of 6.5 years. A subset of these subjects gained excessive weight. We tested for association of polymorphisms in 8 candidate genes with the above trait. We found the Gly482Ser polymorphism in the peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α to be significantly associated with weight gain in males (P=.0045 but not in females. The Ser allele was associated with greater weight gain than the Gly allele (P=.005. Subjects with a family history of type 2 diabetes mellitus (T2DM were more common among those who gained excessive weight. We conclude that T2DM and the Gly482Ser polymorphism in PGC1α contribute to the effect of intensive diabetes therapy on weight gain in males with T1DM.

  8. Distinct Mechanism of Cysteine Oxidation-Dependent Activation and Cold Sensitization of Human Transient Receptor Potential Ankyrin 1 Channel by High and Low Oxaliplatin

    Directory of Open Access Journals (Sweden)

    Takahito Miyake

    2017-11-01

    Full Text Available Oxaliplatin, a third-generation platinum-based chemotherapeutic agent, displays unique acute peripheral neuropathy triggered or enhanced by cold, and accumulating evidence suggests that transient receptor potential ankyrin 1 (TRPA1 is responsible. TRPA1 is activated by oxaliplatin via a glutathione-sensitive mechanism. However, oxaliplatin interrupts hydroxylation of a proline residue located in the N-terminal region of TRPA1 via inhibition of prolyl hydroxylase (PHD, which causes sensitization of TRPA1 to reactive oxygen species (ROS. Furthermore, PHD inhibition endows cold-insensitive human TRPA1 (hTRPA1 with ROS-dependent cold sensitivity. Since cysteine oxidation and proline hydroxylation regulate its activity, their association with oxaliplatin-induced TRPA1 activation and acquirement of cold sensitivity were investigated in the present study. A high concentration of oxaliplatin (1 mM induced outward-rectifier whole-cell currents and increased the intracellular Ca2+ concentration in hTRPA1-expressing HEK293 cells, but did not increase the probability of hTRPA1 channel opening in the inside-out configuration. Oxaliplatin also induced the rapid generation of hydrogen peroxide, and the resultant Ca2+ influx was prevented in the presence of glutathione and in cysteine-mutated hTRPA1 (Cys641Ser-expressing cells, whereas proline-mutated hTRPA1 (Pro394Ala-expressing cells showed similar whole-cell currents and Ca2+ influx. By contrast, a lower concentration of oxaliplatin (100 μM did not increase the intracellular Ca2+ concentration but did confer cold sensitivity on hTRPA1-expressing cells, and this was inhibited by PHD2 co-overexpression. Cold sensitivity was abolished by the mitochondria-targeting ROS scavenger mitoTEMPO and was minimal in cysteine-mutated hTRPA1 (Cys641Ser or Cys665Ser-expressing cells. Thus, high oxaliplatin evokes ROS-mediated cysteine oxidation-dependent hTRPA1 activation independent of PHD activity, while a lower

  9. The safety of high activity long life nuclear waste

    International Nuclear Information System (INIS)

    Devillers, Ch.

    1998-01-01

    The article concerns the deep geological storage for managing high activity long life nuclear waste. He puts forward a context giving a structure to the discussions of those involved concerning an assessment of the safety of a deep geological deposit project. Three main aspects are put forward. The risks for future generations and the time scales to be considered: briefly, the deposit needs to satisfy two functions for protecting man and the environment, namely firstly isolating high activity radionuclides from the biosphere during the time required for their radioactive decay (about ten thousands years), and secondly delay and dilute long life radionuclides without any a priori time limit so as to reduce their effects in the biosphere to extremely low levels. The risks are linked to possible failures of the containment barriers whose causes need to be analysed and be provided against by suitable provisions concerning their design. The definition of these design provisions requires an in depth examination of uncertain elements. The main causes of uncertainty are listed according to the scale of time in question, that is O-10,000 years, 10,000-100,000 years and beyond 100,000 years, stressing the importance of selecting a stable geological site and more generally a solid concept that is not very sensitive in uncertainties. Beyond 100,000 years the extent of uncertainties no longer makes it possible to make realistic predictions. It is thus necessary to consider the alternative scenarios concerning geological and climatic changes and the corresponding increasing risks of radionuclides. The risks in question may be relativized by realizing that on this time scale, the residual activities of soluble and insoluble alpha and beta emitters are comparable to those of a storage centre located on the surface at the end of the monitoring period. Finally, the article considers the approach put forward concerning the safety of a deep geological storage advocated by the French

  10. Doped titanium dioxide nanocrystalline powders with high photocatalytic activity

    International Nuclear Information System (INIS)

    Castro, A.L.; Nunes, M.R.; Carvalho, M.D.; Ferreira, L.P.; Jumas, J.-C.; Costa, F.M.; Florencio, M.H.

    2009-01-01

    Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with anatase structure were successfully synthesized through an hydrothermal route preceded by a precipitation doping step. Structural and morphological characterizations were performed by powder XRD and TEM. Thermodynamic stability studies allowed to conclude that the anatase structure is highly stable for all doped TiO 2 prepared compounds. The photocatalytic efficiency of the synthesized nanopowders was tested and the results showed an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 , whereas no photocatalytic activity was detected for the Fe:TiO 2 and Co:TiO 2 nanopowders. These results were correlated to the doping ions oxidation states, determined by Moessbauer spectroscopy and magnetization data. - Graphical abstract: Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with highly stable anatase structure were successfully synthesized through an hydrothermal route. The photocatalytic efficiencies of the synthesized nanopowders were tested and the results show an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 .

  11. Phosphorylation of Mycobacterium tuberculosis Ser/Thr phosphatase by PknA and PknB.

    Directory of Open Access Journals (Sweden)

    Andaleeb Sajid

    2011-03-01

    Full Text Available The integrated functions of 11 Ser/Thr protein kinases (STPKs and one phosphatase manipulate the phosphorylation levels of critical proteins in Mycobacterium tuberculosis. In this study, we show that the lone Ser/Thr phosphatase (PstP is regulated through phosphorylation by STPKs.PstP is phosphorylated by PknA and PknB and phosphorylation is influenced by the presence of Zn(2+-ions and inorganic phosphate (Pi. PstP is differentially phosphorylated on the cytosolic domain with Thr(137, Thr(141, Thr(174 and Thr(290 being the target residues of PknB while Thr(137 and Thr(174 are phosphorylated by PknA. The Mn(2+-ion binding residues Asp(38 and Asp(229 are critical for the optimal activity of PstP and substitution of these residues affects its phosphorylation status. Native PstP and its phosphatase deficient mutant PstP(c (D38G are phosphorylated by PknA and PknB in E. coli and addition of Zn(2+/Pi in the culture conditions affect the phosphorylation level of PstP. Interestingly, the phosphorylated phosphatase is more active than its unphosphorylated equivalent.This study establishes the novel mechanisms for regulation of mycobacterial Ser/Thr phosphatase. The results indicate that STPKs and PstP may regulate the signaling through mutually dependent mechanisms. Consequently, PstP phosphorylation may play a critical role in regulating its own activity. Since, the equilibrium between phosphorylated and non-phosphorylated states of mycobacterial proteins is still unexplained, understanding the regulation of PstP may help in deciphering the signal transduction pathways mediated by STPKs and the reversibility of the phenomena.

  12. SERS investigations and electrical recording of neuronal networks with three-dimensional plasmonic nanoantennas (Conference Presentation)

    Science.gov (United States)

    De Angelis, Francesco

    2017-06-01

    SERS investigations and electrical recording of neuronal networks with three-dimensional plasmonic nanoantennas Michele Dipalo, Valeria Caprettini, Anbrea Barbaglia, Laura Lovato, Francesco De Angelis e-mail: francesco.deangelis@iit.it Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova Biological systems are analysed mainly by optical, chemical or electrical methods. Normally each of these techniques provides only partial information about the environment, while combined investigations could reveal new phenomena occurring in complex systems such as in-vitro neuronal networks. Aiming at the merging of optical and electrical investigations of biological samples, we introduced three-dimensional plasmonic nanoantennas on CMOS-based electrical sensors [1]. The overall device is then capable of enhanced Raman Analysis of cultured cells combined with electrical recording of neuronal activity. The Raman measurements show a much higher sensitivity when performed on the tip of the nanoantenna in respect to the flat substrate [2]; this effect is a combination of the high plasmonic field enhancement and of the tight adhesion of cells on the nanoantenna tip. Furthermore, when plasmonic opto-poration is exploited [3] the 3D nanoelectrodes are able to penetrate through the cell membrane thus accessing the intracellular environment. Our latest results (unpublished) show that the technique is completely non-invasive and solves many problems related to state-of-the-art intracellular recording approaches on large neuronal networks. This research received funding from ERC-IDEAS Program: "Neuro-Plasmonics" [Grant n. 616213]. References: [1] M. Dipalo, G. C. Messina, H. Amin, R. La Rocca, V. Shalabaeva, A. Simi, A. Maccione, P. Zilio, L. Berdondini, F. De Angelis, Nanoscale 2015, 7, 3703. [2] R. La Rocca, G. C. Messina, M. Dipalo, V. Shalabaeva, F. De Angelis, Small 2015, 11, 4632. [3] G. C. Messina et al., Spatially, Temporally, and Quantitatively Controlled Delivery of

  13. Processing ser and estar to locate objects and events: An ERP study with L2 speakers of Spanish.

    Science.gov (United States)

    Dussias, Paola E; Contemori, Carla; Román, Patricia

    2014-01-01

    In Spanish locative constructions, a different form of the copula is selected in relation to the semantic properties of the grammatical subject: sentences that locate objects require estar while those that locate events require ser (both translated in English as 'to be'). In an ERP study, we examined whether second language (L2) speakers of Spanish are sensitive to the selectional restrictions that the different types of subjects impose on the choice of the two copulas. Twenty-four native speakers of Spanish and two groups of L2 Spanish speakers (24 beginners and 18 advanced speakers) were recruited to investigate the processing of 'object/event + estar/ser ' permutations. Participants provided grammaticality judgments on correct (object + estar ; event + ser ) and incorrect (object + ser ; event + estar ) sentences while their brain activity was recorded. In line with previous studies (Leone-Fernández, Molinaro, Carreiras, & Barber, 2012; Sera, Gathje, & Pintado, 1999), the results of the grammaticality judgment for the native speakers showed that participants correctly accepted object + estar and event + ser constructions. In addition, while 'object + ser ' constructions were considered grossly ungrammatical, 'event + estar ' combinations were perceived as unacceptable to a lesser degree. For these same participants, ERP recording time-locked to the onset of the critical word ' en ' showed a larger P600 for the ser predicates when the subject was an object than when it was an event (*La silla es en la cocina vs. La fiesta es en la cocina). This P600 effect is consistent with syntactic repair of the defining predicate when it does not fit with the adequate semantic properties of the subject. For estar predicates (La silla está en la cocina vs. *La fiesta está en la cocina), the findings showed a central-frontal negativity between 500-700 ms. Grammaticality judgment data for the L2 speakers of Spanish showed that beginners were significantly less accurate than

  14. High salt intake enhances swim stress-induced PVN vasopressin cell activation and active stress coping.

    Science.gov (United States)

    Mitchell, N C; Gilman, T L; Daws, L C; Toney, G M

    2018-07-01

    Stress contributes to many psychiatric disorders; however, responsivity to stressors can vary depending on previous or current stress exposure. Relatively innocuous heterotypic (differing in type) stressors can summate to result in exaggerated neuronal and behavioral responses. Here we investigated the ability of prior high dietary sodium chloride (salt) intake, a dehydrating osmotic stressor, to enhance neuronal and behavioral responses of mice to an acute psychogenic swim stress (SS). Further, we evaluated the contribution of the osmo-regulatory stress-related neuropeptide arginine vasopressin (VP) in the hypothalamic paraventricular nucleus (PVN), one of only a few brain regions that synthesize VP. The purpose of this study was to determine the impact of high dietary salt intake on responsivity to heterotypic stress and the potential contribution of VPergic-mediated neuronal activity on high salt-induced stress modulation, thereby providing insight into how dietary (homeostatic) and environmental (psychogenic) stressors might interact to facilitate psychiatric disorder vulnerability. Salt loading (SL) with 4% saline for 7 days was used to dehydrate and osmotically stress mice prior to exposure to an acute SS. Fluid intake and hematological measurements were taken to quantify osmotic dehydration, and serum corticosterone levels were measured to index stress axis activation. Immunohistochemistry (IHC) was used to stain for the immediate early gene product c-Fos to quantify effects of SL on SS-induced activation of neurons in the PVN and extended amygdala - brain regions that are synaptically connected and implicated in responding to osmotic stress and in modulation of SS behavior, respectively. Lastly, the role of VPergic PVN neurons and VP type 1 receptor (V1R) activity in the amygdala in mediating effects of SL on SS behavior was evaluated by quantifying c-Fos activation of VPergic PVN neurons and, in functional experiments, by nano-injecting the V1R selective

  15. Towards field detection of polycyclic aromatic hydrocarbons (PAHs) in environment water using a self-assembled SERS sensor

    Science.gov (United States)

    Yan, Xia; Shi, Xiaofeng; Yang, Jie; Zhang, Xu; Jia, Wenjie; Ma, Jun

    2017-10-01

    A self-assembled surface enhanced Raman scattering (SERS) sensor is reported in this paper. To achieve high sensitivity, a high sensitive SERS substrate and a high efficient self-constructed light path were made. The SERS substrate was composed by gold nanoparticles (AuNPs, pH=13), glycidyl methacrylate-ethylene dimethacrylate (GMA-EDMA) porous material and syringe filter. The substrate had a good repeatability, and the relative standard deviation (RSD) of the same substrate was less than 5%. The efficiency of the self-constructed light path is about two times better than RPB Y type reflection fiber when the energy density was roughly equal on samples. The size of the SERS sensor is 350×300×180 mm and the weight is 15 kg. Its miniaturization and portable can comply with the requirements of field detection. Besides, it has good sensitivity, stability and selectivity. For lab experiments, strong enhancements of Raman scattering from organic pollutant polycyclic aromatic hydrocarbons (PAHs) molecules were exhibited. The dependences of SERS intensities on concentrations of PAHs were investigated, and the results indicated that they revealed a satisfactory linear relationship in low concentrations. The limits of detection (LODs) of PAHs phenanthrene and fluorene are 8.3×10-10 mol/L and 7.1×10-10 mol/L respectively [signal to noise ratio (S/N) =3]. Based on this SERS sensor, signals of benzo (a) pyrene and pyrene were found in environmental water and the sensor would be an ideal candidate for field detection of PAHs.

  16. Optimization of CMOS active pixels for high resolution digital radiography

    International Nuclear Information System (INIS)

    Kim, Young Soo

    2007-02-01

    CMOS image sensors have poorer performance compared to conventional charge coupled devices (CCDs). Since CMOS Active Pixel Sensors (APSs) in general have higher temporal noise, higher dark current, smaller full well charge capacitance, and lower spectral response, they cannot provide the same wide dynamic range and superior signal-to-noise ratio as CCDs. In view of electronic noise, the main source for the CMOS APS is the pixel, along with other signal processing blocks such as row and column decoder, analog signal processor (ASP), analog-to-digital converter (ADC), and timing and control logic circuitry. Therefore, it is important and necessary to characterize noise of the active pixels in CMOS APSs. We developed our theoretical noise model to account for the temporal noise in active pixels, and then found out the optimum design parameters such as fill actor, each size of the three transistors (source follower, row selection transistor, bias transistor) comprising active pixels, bias current, and load capacitance that can have the maximum signal-to-noise ratio. To develop the theoretical noise model in active pixels, we considered the integration noise of the photodiode and the readout noise of the transistors related to readout. During integration, the shot noise due to the dark current and photocurrent, during readout, the thermal and flicker noise were considered. The developed model can take the input variables such as photocurrent, capacitance of the photodiode, integration time, transconductance of the transistors, channel resistance of the transistors, gate-to-source capacitance of the follower, and load capacitance etc. To validate our noise model, two types of test structures have been realized. Firstly, four types of photodiodes (n_d_i_f_f_u_s_i_o_n/p_s_u_b_s_t_r_a_t_e, n_w_e_l_l/p_s_u_b_s_t_r_a_t_e, n_d_i_f_f_u_s_i_o_n/p_e_p_i_t_a_x_i_a_l/p_s_u_b_s_t_r_a_t_e, n_w_e_l_l/p_e_p_i_t_a_x_i_a_l/p_s_u_b_s_t_r_a_t_e) used in CMOS active pixels were fabricated

  17. Towards SERS based applications in food analytics: Lipophilic sensor layers for the detection of Sudan III in food matrices

    Energy Technology Data Exchange (ETDEWEB)

    Jahn, Martin; Patze, Sophie [Friedrich-Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany); Leibniz Institute of Photonic Technology (IPHT) Jena, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Bocklitz, Thomas [Friedrich-Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany); Weber, Karina [Friedrich-Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany); Leibniz Institute of Photonic Technology (IPHT) Jena, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Cialla-May, Dana, E-mail: dana.cialla-may@uni-jena.de [Friedrich-Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany); Leibniz Institute of Photonic Technology (IPHT) Jena, Albert-Einstein-Strasse 9, 07745 Jena (Germany); Popp, Jürgen [Friedrich-Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany); Leibniz Institute of Photonic Technology (IPHT) Jena, Albert-Einstein-Strasse 9, 07745 Jena (Germany)

    2015-02-20

    Highlights: • A lipophilic sensor layer was applied to enzymatically grown SERS substrates. • Sudan III molecules could be detected in presence of water-insoluble competitors. • The carcinogenic food dye Sudan III was detected in a relevant concentration range. • Multivariate statistics allows quantitative measurements of Sudan III. • Sudan III contaminations were successfully detected out of spiked paprika powder. - Abstract: Food safety is a topic of great importance for our society which places high demands on analytical methods. Surface enhanced Raman spectroscopy (SERS) meets the requirements for a rapid, sensitive and specific detection technique. The fact that metallic colloids, one of the most often used SERS substrates, are usually prepared in aqueous solution makes the detection of water-insoluble substances challenging. In this paper we present a SERS based approach for the detection of water-insoluble molecules by applying a hydrophobic surface modification onto the surface of enzymatic generated silver nanoparticles. By this approach the detection of the illegal water-insoluble food dyes, such as Sudan III in presence of riboflavin, as water-soluble competitor, is possible. Moreover, we demonstrate the usability of this kind of SERS substrates for determination of Sudan III out of spiked paprika extracts.

  18. Towards SERS based applications in food analytics: Lipophilic sensor layers for the detection of Sudan III in food matrices

    International Nuclear Information System (INIS)

    Jahn, Martin; Patze, Sophie; Bocklitz, Thomas; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2015-01-01

    Highlights: • A lipophilic sensor layer was applied to enzymatically grown SERS substrates. • Sudan III molecules could be detected in presence of water-insoluble competitors. • The carcinogenic food dye Sudan III was detected in a relevant concentration range. • Multivariate statistics allows quantitative measurements of Sudan III. • Sudan III contaminations were successfully detected out of spiked paprika powder. - Abstract: Food safety is a topic of great importance for our society which places high demands on analytical methods. Surface enhanced Raman spectroscopy (SERS) meets the requirements for a rapid, sensitive and specific detection technique. The fact that metallic colloids, one of the most often used SERS substrates, are usually prepared in aqueous solution makes the detection of water-insoluble substances challenging. In this paper we present a SERS based approach for the detection of water-insoluble molecules by applying a hydrophobic surface modification onto the surface of enzymatic generated silver nanoparticles. By this approach the detection of the illegal water-insoluble food dyes, such as Sudan III in presence of riboflavin, as water-soluble competitor, is possible. Moreover, we demonstrate the usability of this kind of SERS substrates for determination of Sudan III out of spiked paprika extracts

  19. Low-cost and large-scale flexible SERS-cotton fabric as a wipe substrate for surface trace analysis

    Science.gov (United States)

    Chen, Yanmin; Ge, Fengyan; Guang, Shanyi; Cai, Zaisheng

    2018-04-01

    The large-scale surface enhanced Raman scattering (SERS) cotton fabrics were fabricated based on traditional woven ones using a dyeing-like method of vat dyes, where silver nanoparticles (Ag NPs) were in-situ synthesized by 'dipping-reducing-drying' process. By controlling the concentration of AgNO3 solution, the optimal SERS cotton fabric was obtained, which had a homogeneous close packing of Ag NPs. The SERS cotton fabric was employed to detect p-Aminothiophenol (PATP). It was found that the new fabric possessed excellent reproducibility (about 20%), long-term stability (about 57 days) and high SERS sensitivity with a detected concentration as low as 10-12 M. Furthermore, owing to the excellent mechanical flexibility and good absorption ability, the SERS cotton fabric was employed to detect carbaryl on the surface of an apple by simply swabbing, which showed great potential in fast trace analysis. More importantly, this study may realize large-scale production with low cost by a traditional cotton fabric.

  20. Highly sensitive assay for tyrosine hydroxylase activity by high-performance liquid chromatography.

    Science.gov (United States)

    Nagatsu, T; Oka, K; Kato, T

    1979-07-21

    A highly sensitive assay for tyrosine hydroxylase (TH) activity by high-performance liquid chromatography (HPLC) with amperometric detection was devised based on the rapid isolation of enzymatically formed DOPA by a double-column procedure, the columns fitted together sequentially (the top column of Amberlite CG-50 and the bottom column of aluminium oxide). DOPA was adsorbed on the second aluminium oxide column, then eluted with 0.5 M hydrochloric acid, and assayed by HPLC with amperometric detection. D-Tyrosine was used for the control. alpha-Methyldopa was added to the incubation mixture as an internal standard after incubation. This assay was more sensitive than radioassays and 5 pmol of DOPA formed enzymatically could be measured in the presence of saturating concentrations of tyrosine and 6-methyltetrahydropterin. The TH activity in 2 mg of human putamen could be easily measured, and this method was found to be particularly suitable for the assay of TH activity in a small number of nuclei from animal and human brain.

  1. Trace detection of tetrahydrocannabinol (THC) with a SERS-based capillary platform prepared by the in situ microwave synthesis of AgNPs.

    Science.gov (United States)

    Yüksel, Sezin; Schwenke, Almut M; Soliveri, Guido; Ardizzone, Silvia; Weber, Karina; Cialla-May, Dana; Hoeppener, Stephanie; Schubert, Ulrich S; Popp, Jürgen

    2016-10-05

    In the present study, an ultra-sensitive and highly reproducible novel SERS-based capillary platform was developed and utilized for the trace detection of tetrahydrocannabinol (THC). The approach combines the advantages of microwave-assisted nanoparticle synthesis, plasmonics and capillary forces. By employing a microwave-assisted preparation method, glass capillaries were reproducibly coated with silver nanoparticles in a batch fabrication process that required a processing time of 3 min without needing to use any pre-surface modifications or add surfactants. The coated capillaries exhibited an excellent SERS activity with a high reproducibility and enabled the detection of low concentrations of target molecules. At the same time, only a small amount of analyte and a short and simple incubation process was required. The developed platform was applied to the spectroscopic characterization of tetrahydrocannabinol (THC) and its identification at concentration levels down to 1 nM. Thus, a highly efficient detection system for practical applications, e.g., in drug monitoring/detection, is introduced, which can be fabricated at low cost by using microwave-assisted batch synthesis techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Fabrication of a novel transparent SERS substrate comprised of Ag-nanoparticle arrays and its application in rapid detection of ractopamine on meat

    Science.gov (United States)

    Surface-enhanced Raman spectroscopy (SERS) is an emerging analytical tool that boasts the feature of high detection sensitivity and molecular fingerprint specificity attracting increased attention and showing promise in applications including detecting residues of veterinary drugs. In practice, spec...

  3. Surface-enhanced Raman spectroscopy (SERS) in food analytics: Detection of vitamins B2 and B12 in cereals.

    Science.gov (United States)

    Radu, Andreea Ioana; Kuellmer, Maria; Giese, Bernd; Huebner, Uwe; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2016-11-01

    Food analysis has been gaining interest throughout recent decades for different reasons: the detection of hazardous substances in food and routine investigations of food composition and vitamin/nutrient contents. Regardless of the targeted component, food analysis raises a few challenges regarding the complexity of the matrix and detecting trace amounts of substances. We report herein the results obtained regarding the simultaneous detection of two B vitamins (riboflavin, vitamin B2 and cyanocobalamin, vitamin B12) by means of SERS. SERS provides molecular fingerprint identification and high analytical sensitivity together with a low processing time and cost. All these make SERS a promising tool for the development of food analytical methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Facile fabrication of homogeneous 3D silver nanostructures on gold-supported polyaniline membranes as promising SERS substrates.

    Science.gov (United States)

    Xu, Ping; Mack, Nathan H; Jeon, Sea-Ho; Doorn, Stephen K; Han, Xijiang; Wang, Hsing-Lin

    2010-06-01

    We report a facile synthesis of large-area homogeneous three-dimensional (3D) Ag nanostructures on Au-supported polyaniline (PANI) membranes through a direct chemical reduction of metal ions by PANI. The citric acid absorbed on the Au nuclei that are prefabricated on PANI membranes directs Ag nanoaprticles (AgNPs) to self-assemble into 3D Ag nanosheet structures. The fabricated hybrid metal nanostructures display uniform surface-enhanced Raman scattering (SERS) responses throughout the whole surface area, with an average enhancement factor of 10(6)-10(7). The nanocavities formed by the stereotypical stacking of these Ag nanosheets and the junctions and gaps between two neighboring AgNPs are believed to be responsible for the strong SERS response upon plasmon absorption. These homogeneous metal nanostructure decorated PANI membranes can be used as highly efficient SERS substrates for sensitive detection of chemical and biological analytes.

  5. Stacking faults enriched silver nanowires: facile synthesis, catalysis and SERS investigations.

    Science.gov (United States)

    Xu, Minmin; Yang, Fengzhu; Yuan, Yaxian; Guo, Qinghua; Ren, Bin; Yao, Jianlin; Gu, Renao

    2013-10-01

    A facile approach based on seed-mediated method for synthesis of stacking faults enriched Ag nanowires (SFEANWs) was successfully developed. SFEANWs were formed and attached onto the seed (α-Fe2O3/Au) surfaces through the reduction of AgNO3 by ascorbic acid (AA) in the presence of sodium polyacrylate (PAANa). Their length can be tuned with different concentrations of AgNO3 or PAANa. According to the effects of seeds and PAANa, the plausible growth mechanism of SFEANWs was discussed. The catalytic activity of SFEANWs comparing with fivefold twinned Ag nanowires (FFTANWs) was evaluated through reducing p-nitrophenol by NaBH4. The activation energy of the classical reaction catalyzed by SFEANWs was calculated through the Arrhenius equation. In addition, these SFEANWs exhibited excellent surface enhanced Raman scattering (SERS) activities due to the hot spots located in the cross of the twist wires. The detection limit of by SERS for 1,4-benzenedithiol (1,4-BDT) was estimated about 10(-7) mol/L. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Superhydrophobic analyte concentration utilizing colloid-pillar array SERS substrates.

    Science.gov (United States)

    Wallace, Ryan A; Charlton, Jennifer J; Kirchner, Teresa B; Lavrik, Nickolay V; Datskos, Panos G; Sepaniak, Michael J

    2014-12-02

    The ability to detect a few molecules present in a large sample is of great interest for the detection of trace components in both medicinal and environmental samples. Surface enhanced Raman spectroscopy (SERS) is a technique that can be utilized to detect molecules at very low absolute numbers. However, detection at trace concentration levels in real samples requires properly designed delivery and detection systems. The following work involves superhydrophobic surfaces that have as a framework deterministic or stochastic silicon pillar arrays formed by lithographic or metal dewetting protocols, respectively. In order to generate the necessary plasmonic substrate for SERS detection, simple and flow stable Ag colloid was added to the functionalized pillar array system via soaking. Native pillars and pillars with hydrophobic modification are used. The pillars provide a means to concentrate analyte via superhydrophobic droplet evaporation effects. A ≥ 100-fold concentration of analyte was estimated, with a limit of detection of 2.9 × 10(-12) M for mitoxantrone dihydrochloride. Additionally, analytes were delivered to the surface via a multiplex approach in order to demonstrate an ability to control droplet size and placement for scaled-up uses in real world applications. Finally, a concentration process involving transport and sequestration based on surface treatment selective wicking is demonstrated.

  7. Neutron activation analysis of high pure uranium using preconcentration

    International Nuclear Information System (INIS)

    Sadikov, I.I.; Rakhimov, A.V.; Salimov, M.I.; Zinov'ev, V.G.

    2006-01-01

    Full text: Uranium and its compounds are used as nuclear fuel, and requirements for purity of initial uranium are very high. Therefore highly sensitive and multielemental analysis of uranium is required. One of such methods is neutron activation analysis (NAA). During irradiation of uranium by nuclear reactor neutrons the induced radioactivity of a sample is formed by uranium radionuclide 239 U (T 1/2 = 23,4 min.) and its daughter radionuclide 239 Np (T 1/2 = 2,39 d). Short-lived 239 U almost completely decays in 24 hours after irradiation and the radioactivity of the sample is mainly due to 239 Np and is more than 10 9 Bq for 0.1 g of uranium sample (F = 1*10 14 cm -2 s -1 , t irr . = 5 h). That is why nondestructive determination of the impurities is impossible and they should be separated from 239 Np. When irradiated uranium yields fission products - radionuclides of some elements with mass numbers 91-104 and 131-144. The main problem in NAA of uranium is to take into account correctly the influence of fission products on the analysis results. We have developed a radiochemical separation procedure for RNAA of uranium [1]. Comparing the results of analysis carried out by radiochemical NAA and instrumental NAA with preconcentration of trace elements can be used for evaluating the interference of fission products on uranium analysis results. Preconcentration of trace elements have been carried out by extraction chromatography in 'TBP - 6M HNO 3 ' system [1]. Experiments have shown that if 0.1 g uranium sample is taken for analysis (F = 1*10 14 cm -2 s -1 , t irr . =5 h) the apparent concentration of Y, Zr, Mo, Cs, La, Ce, Pr, Nd exceeds the true concentration by 2500-3000 times and so determination of these elements is not possible by radiochemical NAA. (author)

  8. A gold nanostar-based SERS platform for point-of-care diagnostics of carbapenemase-producing enterobacteriacae

    Science.gov (United States)

    Kang, Wei Cherng Malvin; Wong, Yen Lynn; Piotrowski, Marek; Teo, Woon Pei J.; He, Shuai; Kah, James C.

    2017-04-01

    The ever-increasing spread and emergence of antibiotic resistance poses a serious threat to global public health. With the existence of Carbapenem-resistant Enterobacteriaceae (CRE) produced by the Klebsiella Pneumoniae bacteria, it renders the use of carbapenems, the last-resort class of β-lactam antibiotics, useless against combating against bacterial infections. Such infections reduce the ability to treat complex infections due to the lack of antibiotic options for treatment, leading to CRE-associated mortalities. Current methods of detection, like CarbaNP test and Modified Hodge's Test, have significant limitations in that the time taken for detection of carbapenemase activity ranges between hours to days, and are non-specific in detecting the specific phenotype, making it challenging to isolate patients rapidly and to devise appropriate treatment for infected patients. We propose a methodology by utilising Surface Enhanced Raman Spectroscopy (SERS) to study bacterial β-lactamase activity. This is done via the use of gold nanostars (AuNS), which have reported excellent SERS properties, conjugated with a β-lactam antibiotic ceftriaxole, as a proof-of-concept study to analyse the changes in the SERS spectra associated with cleavage of the β-lactam ring upon interaction with the New Delhi Metalloproteinase (NDM)- producing Escherichia coli (Class B β-lactamase). We are able to obtain detection of carbapenemase activity within 25 minutes, with the associated changes in SERS spectra being diminishing of SERS peaks at 1358cm-1 and 1495cm-1. This project can be further extended to study the activity of other classes of β-lactamases and other β-lactam antibiotics to improve this state of technology for potential adoption by healthcare institutions.

  9. A lipoprotein lipase mutation (Asn291Ser) is associated with reduced HDL cholesterol levels in premature atherosclerosis

    NARCIS (Netherlands)

    Reymer, P.W.A.; Gagné, S E; Groenemeyer, B E; Zhang, H; Forsyth, I; Jansen, H; Seidell, J C; Kromhout, D.; Lie, K E; Kastelein, J.J.

    1995-01-01

    A reduction of high density lipoprotein cholesterol (HDC) is recognized as an important risk factor for coronary artery disease (CAD). We now show in approximately 1 in 20 males with proven atherosclerosis that an Asn291Ser mutation in the human lipoprotein lipase (LPL) gene is associated with

  10. ATM phosphorylation of Mdm2 Ser394 regulates the amplitude and duration of the DNA damage response in mice

    Science.gov (United States)

    Gannon, Hugh S.; Woda, Bruce A.; Jones, Stephen N.

    2012-01-01

    Summary DNA damage induced by ionizing radiation (IR) activates the ATM kinase, which subsequently stabilizes and activates the p53 tumor suppressor protein. Although phosphorylation of p53 by ATM was found previously to modulate p53 levels and transcriptional activities in vivo, it does not appear to be a major regulator of p53 stability. We have utilized mice bearing altered Mdm2 alleles to demonstrate that ATM phosphorylation of Mdm2 serine 394 is required for robust p53 stabilization and activation after DNA damage. In addition, we demonstrate that dephosphorylation of Mdm2 Ser394 regulates attenuation of the p53-mediated response to DNA damage. Therefore, the phosphorylation status of Mdm2 Ser394 governs p53 protein levels and functions in cells undergoing DNA damage. PMID:22624716

  11. Investigation of possible association between Ser9Gly polymorphism of the D3 dopaminergic receptor gene and response to typical antipsychotics in patients with schizophrenia

    Directory of Open Access Journals (Sweden)

    Quirino Cordeiro

    Full Text Available Typical antipsychotics have a high affinity for dopamine receptors. It is therefore of interest to investigate such loci in pharmacogenetic studies on psychosis. We investigated the hypothesis that Ser9Gly polymorphism of the DRD3 gene may play a role in the differences in individual response to typical antipsychotics between schizophrenic patients. The sample was composed of 53 good responders and 59 poor ones. No significant differences between the good and poor responders were found in the allelic distribution (good responders: Ser9 61.32%, Gly9 38.67%; poor responders: Ser9 64.40%, Gly9 35.59%; odds ratio, OR = 0.88, 0.49 < OR < 1.56; chi2 = 0.23, 1 degree of freedom, df, p = 0.63 and genotype distribution (good responders: Ser9/Ser9 37.73%, Ser9/Gly9 47.16%, Gly9/Gly9 15.09%; poor responders: Ser9/Ser9 42.37%, Ser9/Gly9 44.06%, Gly9/Gly9 13.55%; chi2 = 0.25, 2 df, p = 0.88. Nor was there any association with homozygosity (good responders: homozygous: 52.82%, heterozygous: 47.16%; poor responders: homozygous: 55.92%, heterozygous: 44.06%; odds ratio, OR = 0.88, 0.39 < OR < 1.99; chi2 = 0.11, 1 df, p = 0.74. The results did not support the hypothesis that Ser9Gly polymorphism of the DRD3 gene influences the response to typical antipsychotics in our sample of schizophrenics.

  12. Highly active vitrification plant remote handling operational experience and improvements

    International Nuclear Information System (INIS)

    Milgate, I.

    1996-01-01

    All the main process plant and equipment at the Sellafield Waste Vitrification Plant (WVP) is enclosed in heavily shielded concrete walled cells. There is a large quantity of relatively complex plant and equipment which must be remotely operated, maintained or replaced in-cell in a severe environment. The WVP has five in-cell polar cranes which are of modular construction to aid replacement of failed components. Each can be withdrawn into a shielded cell extension for decontamination and hands-on maintenance. The cells have a total of 80 through wall tube positions to receive Master Slave Manipulators (MSMs). The MSMs are used where possible for ''pick and place'' purposes but are often called upon to position substantial pieces of mechanical equipment and thus are subject to heavy loading and high failure rates. An inward flow of air is maintained in the active cells. The discharged air passes through a filter cell where remote damper operation filter changing and maintenance is carried out by means of a PAR3000 manipulator. A Nuclear Engineered Advanced Teleoperated Robot (Neater) swabs the vitrified product container to ensure cleanliness before storage. There is a significant arising of solid radioactive waste from replaced in-cell items which undergoes sorting and size reduction in a breakdown cell equipped with a large reciprocating saw and a hydraulic shear. Improvements to the remote handling facilities made in the light of operational experience are described. (UK)

  13. Lead corrosion evaluation in high activity nuclear waste container (Argentina)

    International Nuclear Information System (INIS)

    Guasp, R.; Lanzani, L.; Bruzzoni, P.; Cufre, W.; Semino, C.J.

    2000-01-01

    This report describes a study of high activity nuclear waste canister corrosion in a deep geological disposal. In this canister design, the vitrified nuclear waste stainless steel container is shielded by a 100 mm thick lead wall. For mechanical resistance, the canister will also have a thin carbon steel external liner. Experimental and mathematical modeling studies are aimed to asses the corrosion kinetics of the carbon steel liner in first instance and then, once this liner has been corroded away, the corrosion kinetics of the main lead barrier. Being that oxygen reduction is the main cathodic reaction that supports the anodic oxidation of iron, a model is described predicting the rate of oxygen consumption in a sealed deep nuclear waste disposal vault as a result of the canister corrosion. Oxidation processes other than container corrosion, and that can account also for oxygen depletion, are not taken into consideration. Corrosion experimental studies on lead and its alloys in groundwater are also reported. These experiments are aimed to improve the corrosion resistance of commercial lead in groundwater. (author)

  14. ''Cold crucible'' vitrification projects for low and high active waste

    International Nuclear Information System (INIS)

    Roux, P.; Jouan, A.

    1998-01-01

    In continuity of the CEA HLW vitrification process experienced for more than 20 years in industrial operations in Cogema reprocessing plants (Marcoule and La Hague), CEA has developed an advanced extended performance cold crucible glass melter to address a wider range of waste like LLW, ILW and in particular waste with very corrosive species or requiring glass with higher elaboration temperature. In the cold crucible melter the bath of molten glass is directly heated by induction while the walls are cooled in order to freeze a protective glass layer. This technology subsequently allows high glass throughput while keeping the flexibility, the maintainability and low secondary waste generation related to a small metallic melter. Its recent use in the glass industry and the thousands of hours of pilot tests performed on inactive surrogates have demonstrated the maturity of this technology and its flexibility of use for processing most of the waste generated at nuclear facilities. SGN has therefore proposed this technology in Italy and Korea and in USA in the frame of the Hanford Privatization phase 1 A feasibility study. Main features of this study but also tests results with Hanford surrogates and active samples are discussed. (author)

  15. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2013-01-01

    of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active

  16. Inability of p53-reactivating compounds Nutlin-3 and RITA to overcome p53 resistance in tumor cells deficient in p53Ser46 phosphorylation.

    Science.gov (United States)

    Ma, Teng; Yamada, Shumpei; Ichwan, Solachuddin J A; Iseki, Sachiko; Ohtani, Kiyoshi; Otsu, Megumi; Ikeda, Masa-Aki

    2012-01-20

    The p53 tumor suppressor protein plays key roles in protecting cells from tumorigenesis. Phosphorylation of p53 at Ser46 (p53Ser46) is considered to be a crucial modification regulating p53-mediated apoptosis. Because the activity of p53 is impaired in most human cancers, restoration of wild-type p53 (wt-p53) function by its gene transfer or by p53-reactivating small molecules has been extensively investigated. The p53-reactivating compounds Nutlin-3 and RITA activate p53 in the absence of genotoxic stress by antagonizing the action of its negative regulator Mdm2. Although controversial, Nutlin-3 was shown to induce p53-mediated apoptosis in a manner independent of p53 phosphorylation. Recently, RITA was shown to induce apoptosis by promoting p53Ser46 phosphorylation. Here we examined whether Nutlin-3 or RITA can overcome resistance to p53-mediated apoptosis in p53-resistant tumor cell lines lacking the ability to phosphorylate p53Ser46. We show that Nutlin-3 did not rescue the apoptotic defect of a Ser46 phosphorylation-defective p53 mutant in p53-sensitive tumor cells, and that RITA neither restored p53Ser46 phosphorylation nor induced apoptosis in p53Ser46 phosphorylation-deficient cells retaining wt-p53. Furthermore, treatment with Nutlin-3 or RITA together with adenoviral p53 gene transfer also failed to induce apoptosis in p53Ser46 phosphorylation-deficient cells either expressing or lacking wt-p53. These results indicate that neither Nutlin-3 nor RITA in able to induce p53-mediated apoptosis in the absence of p53Ser46 phosphorylation. Thus, the dysregulation of this phosphorylation in tumor cells may be a critical factor that limits the efficacy of these p53-based cancer therapies. Copyright © 2011 Elsevier Inc. All rights reserved.