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Sample records for sensitive nanoprobes binary

  1. A novel nanoprobe for the sensitive detection of Francisella tularensis.

    PubMed

    Kim, Ji-eun; Seo, Youngmin; Jeong, Yoon; Hwang, Mintai P; Hwang, Jangsun; Choo, Jaebum; Hong, Jong Wook; Jeon, Jun Ho; Rhie, Gi-eun; Choi, Jonghoon

    2015-11-15

    Francisella tularensis is a human zoonotic pathogen and the causative agent of tularemia, a severe infectious disease. Given the extreme infectivity of F. tularensis and its potential to be used as a biological warfare agent, a fast and sensitive detection method is highly desirable. Herein, we construct a novel detection platform composed of two units: (1) Magnetic beads conjugated with multiple capturing antibodies against F. tularensis for its simple and rapid separation and (2) Genetically-engineered apoferritin protein constructs conjugated with multiple quantum dots and a detection antibody against F. tularensis for the amplification of signal. We demonstrate a 10-fold increase in the sensitivity relative to traditional lateral flow devices that utilize enzyme-based detection methods. We ultimately envision the use of our novel nanoprobe detection platform in future applications that require the highly-sensitive on-site detection of high-risk pathogens. PMID:26057442

  2. A highly sensitive and flexible magnetic nanoprobe labeled immunochromatographic assay platform for pathogen Vibrio parahaemolyticus.

    PubMed

    Liu, Yingying; Zhang, Zhaohuan; Wang, Yilong; Zhao, Yong; Lu, Ying; Xu, Xiaowei; Yan, Jun; Pan, Yingjie

    2015-10-15

    A magnetic nanoprobe labeled immunochromatographic test strip (MNP/ICTS) was developed to detect food-borne pathogen Vibrio parahaemolyticus. Specific antibody against V. parahaemolyticus was used as test line by coating onto the nitrocellulose membrane. Magnetic nanoprobe was prepared by immobilizing the specific antibody onto the surface of superparamagnetic nanoparticles. Specificity and sensitivity of the MNP/ICTS system were verified by artificially contaminated shrimp homogenate samples. Reliability and application feasibility of the MNP/ICTS system were demonstrated by using seafood samples (n=36). Comparing with polymerase chain reaction (PCR) and traditional culture methods, the MNP/ICTS system is found to be not only a rapid qualitative analysis (~10 min), but also an accurately quantitative detection platform. Through its rapid magnetic separation property, the MNP/ICTS system is capable to flexibly combine with a sample enrichment and pre-incubation process. This combination makes the qualitative sensitivity for the food samples surged more than 100-fold. A naked-eye observation of 1.58×10(2) CFU/g V. parahaemolyticus was realized. This sensitivity could meet the V. parahaemolyticus test threshold value in many countries. Also, the total sample pre-treatment plus MNP/ICTS assay only needs about 4.5h. Namely, we can get test results in a day. Hence, the developed MNP/ICTS assay platform is simple, rapid and highly sensitive. It is a flexible test platform for pathogen detection. The favorable comparison with PCR and culture methods further proves that the developed MNP/ICTS is applicable into food-borne pathogen or other areas where a simple, rapid, sensitive and point-of-care analysis is desirable. PMID:26188497

  3. Photon upconversion sensitized nanoprobes for sensing and imaging of pH

    NASA Astrophysics Data System (ADS)

    Arppe, Riikka; Näreoja, Tuomas; Nylund, Sami; Mattsson, Leena; Koho, Sami; Rosenholm, Jessica M.; Soukka, Tero; Schäferling, Michael

    2014-05-01

    Acidic pH inside cells indicates cellular dysfunctions such as cancer. Therefore, the development of optical pH sensors for measuring and imaging intracellular pH is a demanding challenge. The available pH-sensitive probes are vulnerable to e.g. photobleaching or autofluorescence background in biological materials. Our approach circumvents these problems due to near infrared excitation and upconversion photoluminescence. We introduce a nanosensor based on upconversion resonance energy transfer (UC-RET) between an upconverting nanoparticle (UCNP) and a fluorogenic pH-dependent dye pHrodo™ Red that was covalently bound to the aminosilane surface of the nanoparticles. The sensitized fluorescence of the pHrodo™ Red dye increases strongly with decreasing pH. By referencing the pH-dependent emission of pHrodo™ Red with the pH-insensitive upconversion photoluminescence of the UCNP, we developed a pH-sensor which exhibits a dynamic range from pH 7.2 to 2.5. The applicability of the introduced pH nanosensor for pH imaging was demonstrated by imaging the two emission wavelengths of the nanoprobe in living HeLa cells with a confocal fluorescence microscope upon 980 nm excitation. This demonstrates that the presented pH-nanoprobe can be used as an intracellular pH-sensor due to the unique features of UCNPs: excitation with deeply penetrating near-infrared light, high photostability, lack of autofluorescence and biocompatibility due to an aminosilane coating.Acidic pH inside cells indicates cellular dysfunctions such as cancer. Therefore, the development of optical pH sensors for measuring and imaging intracellular pH is a demanding challenge. The available pH-sensitive probes are vulnerable to e.g. photobleaching or autofluorescence background in biological materials. Our approach circumvents these problems due to near infrared excitation and upconversion photoluminescence. We introduce a nanosensor based on upconversion resonance energy transfer (UC-RET) between an

  4. Reaction-Driven Self-Assembled Micellar Nanoprobes for Ratiometric Fluorescence Detection of CS2 with High Selectivity and Sensitivity.

    PubMed

    Lu, Wei; Xiao, Peng; Liu, Zhenzhong; Gu, Jincui; Zhang, Jiawei; Huang, Youju; Huang, Qing; Chen, Tao

    2016-08-10

    The detection of highly toxic CS2, which is known as a notorious occupational hazard in various industrial processes, is important from both environmental and public safety perspectives. We describe here a robust type of chemical-reaction-based supramolecular fluorescent nanoprobes for ratiometric determination of CS2 with high selectivity and sensitivity in water medium. The micellar nanoprobes self-assemble from amphiphilic pyrene-modified hyperbranched polyethylenimine (Py-HPEI) polymers with intense pyrene excimer emission. Selective sensing is based on a CS2-specific reaction with hydrophilic amino groups to produce hydrophobic dithiocarbamate moieties, which can strongly quench the pyrene excimer emission via a known photoinduced electron transfer (PET) mechanism. Therefore, the developed micellar nanoprobes are free of the H2S interference problem often encountered in the widely used colorimetric assays and proved to show high selectivity over many potentially competing chemical species. Importantly, the developed approach is capable of CS2 sensing even in complex tap and river water samples. In addition, in view of the modular design principle of these powerful micellar nanoprobes, the sensing strategy used here is expected to be applicable to the development of various sensory systems for other environmentally important guest species. PMID:27419849

  5. Highly selective and sensitive nanoprobes for cyanide based on gold nanoclusters with red fluorescence emission

    NASA Astrophysics Data System (ADS)

    Zhang, Guomei; Qiao, Yunyun; Xu, Ting; Zhang, Caihong; Zhang, Yan; Shi, Lihong; Shuang, Shaomin; Dong, Chuan

    2015-07-01

    We report a novel and environmentally friendly fluorescent probe for detecting the cyanide ion (CN-) using l-amino acid oxidase (LAAOx)-protected Au nanoclusters (LAAOx@AuNCs) with red emission. The fluorescence-based sensing behaviour of LAAOx@AuNCs towards anions was investigated in buffered aqueous media. Among the anions studied, CN- was found to effectively quench the fluorescence emission of AuNCs based on CN- induced Au core decomposition. Excellent sensitivity and selectivity toward the detection of CN- in aqueous solution were observed. The CN- detection limit was determined to be approximately 180 nM, which is 15 times lower than the maximum level (2700 nM) of CN- in drinking water permitted by the World Health Organization (WHO). A linear relationship between the fluorescence intensity and CN- concentration was observed in two ranges of CN- concentration, including 3.2 × 10-6 to 3.4 × 10-5 mol L-1 and 3.81 × 10-5 to 1.04 × 10-4 mol L-1. The high sensitivity and selectivity to CN- among the 17 types of anions make the AuNCs good candidates for use in fluorescent nanoprobes of CN-.

  6. FRET-based biofriendly apo-GO(x)-modified gold nanoprobe for specific and sensitive glucose sensing and cellular imaging.

    PubMed

    Li, Lu; Gao, Feifei; Ye, Jian; Chen, Zhenzhen; Li, Qingling; Gao, Wen; Ji, Lifei; Zhang, Ruirui; Tang, Bo

    2013-10-15

    In this paper, we have developed a biofriendly and high sensitive apo-GOx (inactive form of glucose oxidase)-modified gold nanoprobe for quantitative analysis of glucose and imaging of glucose consumption in living cells. This detection system is based on fluorescence resonance energy transfer between apo-GOx modified AuNPs (Au nanoparticles) and dextran-FITC (dextran labeled with fluorescein isothiocyanate). Once glucose is present, quenched fluorescence of FITC recovers due to the higher affinity of apo-GOx for glucose over dextran. The nanoprobe shows excellent selectivity toward glucose over other monosaccharides and most biological species present in living cells. A detection limit as low as 5 nM demonstrates the high sensitivity of the nanoprobe. Introduction of apo-GOx, instead of GOx, can avoid the consumption of O2 and production of H2O2 during the interaction with glucose, which may exert effects on normal physiological events in living cells and even lead to cellular damage. Due to the low toxicity of this detection system and reliable cellular uptake ability of AuNPs, imaging of intracellular glucose consumption was successfully realized in cancer cells. PMID:24032474

  7. Dual-emitting quantum dot/carbon nanodot-based nanoprobe for selective and sensitive detection of Fe(3+) in cells.

    PubMed

    Wang, Chuanxi; Huang, Yijun; Jiang, Kaili; Humphrey, Mark G; Zhang, Chi

    2016-07-21

    A novel dual-emitting fluorescence probe is developed for rapid and ultrasensitive detection of Fe(3+). The nanoprobe is prepared by coating CdSe semiconductor quantum dots (SQDs) onto the surface of carbon nanodot (CND) doped TiO2 microspheres. The as-prepared nanoprobe exhibits the corresponding dual emissions at 436 and 596 nm for CNDs and CdSe, respectively, under a single excitation wavelength. The blue fluorescence of the CNDs is insensitive to Fe(3+), whereas the orange emission of the CdSe SQDs is functionalized to be selectively quenched by Fe(3+). The intensity ratio of I436/I596 shows a good linear relationship with the concentration of Fe(3+) in the range of 10(-9) to 10(-5) M. The nanoprobe provides an effective platform for the reliable detection of Fe(3+) with a detection limit as low as 10 nM. Besides, this ratiometric nanosensor exhibits good selectivity for Fe(3+) over other metal ions. The results reveal that the nanoprobe could provide a sensitive sensor for rapid detection of Fe(3+) with high selectivity and sensitivity. Moreover, 293T cells are used as models to achieve a potential application as a probe for monitoring Fe(3+) in cells. Thus, these dual-emitting nanoprobes could work as an alternative to conventional fluorescence probes for biolabeling, sensing and other applications. PMID:27197565

  8. Monodispersity of magnetic immuno-nanoprobes enhances the detection sensitivity of low abundance biomarkers in one drop of serum.

    PubMed

    Capangpangan, Rey Y; dela Rosa, Mira Anne C; Obena, Rofeamor P; Chou, Yu-Jen; Tzou, Der-Lii; Shih, Shao-Ju; Chiang, Ming-Hsi; Lin, Chun-Cheng; Chen, Yu-Ju

    2015-11-21

    To enhance the detection sensitivity of target clinical protein biomarkers, a simple and rapid nanoprobe-based immuno-affinity mass spectrometry assay employing biocompatible monodisperse magnetic nanoparticles (MNPs) is reported herein. The MNPs were synthesized via a streamlined protocol that includes (a) fabrication of core MNPs using the thermal decomposition method to minimize aggregation, (b) surface protection by gold coating (MNP@Au) and surfactant coating using MNP@IGEPAL to improve hydrophilicity, and lastly, (c) oriented functionalization of antibodies to maximize immuno-affinity. The enrichment performances of the monodisperse MNPs for the C-reactive protein (CRP) serum biomarker were then evaluated and compared with aggregated magnetic nanoparticles synthesized from the conventional co-precipitation method (MNP(CP)). The detection sensitivity for CRP at an extremely low amount of serum sample (1 μL) was enhanced ∼19- and ∼15-fold when monodisperse MNP@Au and MNP@IGEPAL, respectively, were used. Furthermore, the detection sensitivity of CRP by this approach (1 ng mL(-1), S/N = 3) provided a 1000-fold sensitivity enhancement to the clinical cut-off (1 μg mL(-1)) of CRP. We supposed that these observed improvements are due to the enhanced nanoparticle dispersibility and size uniformity which eliminated completely other non-specific binding of high-abundance serum proteins. Most interestingly, the enrichment efficiency correlates more closely with the MNP dispersibility than the ligand density. Our investigation revealed the critical role of MNP dispersibility, as well as provided mechanistic insight into its impact on immunoaffinity enrichment and detection of CRP in one drop of serum sample. This strategy offers an essential advantage over the other methods by providing a simple and facile biofunctionalization protocol while maintaining excellent solvent dispersibility of MNPs. PMID:26447802

  9. A cobalt oxyhydroxide nanoflake-based nanoprobe for the sensitive fluorescence detection of T4 polynucleotide kinase activity and inhibition.

    PubMed

    Cen, Yao; Yang, Yuan; Yu, Ru-Qin; Chen, Ting-Ting; Chu, Xia

    2016-04-14

    Phosphorylation of nucleic acids with 5'-OH termini catalyzed by polynucleotide kinase (PNK) is an inevitable process and has been implicated in many important cellular events. Here, we found for the first time that there was a significant difference in the adsorbent ability of cobalt oxyhydroxide (CoOOH) nanoflakes between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), which resulted in the fluorescent dye-labeled dsDNA still retaining strong fluorescence emission, while the fluorescence signal of ssDNA was significantly quenched by CoOOH nanoflakes. Based on this discovery, we developed a CoOOH nanoflake-based nanoprobe for the fluorescence sensing of T4 PNK activity and its inhibition by combining it with λ exonuclease cleavage reaction. In the presence of T4 PNK, dye-labeled dsDNA was phosphorylated and then cleaved by λ exonuclease to generate ssDNA, which could adsorb on the CoOOH nanoflakes and whose fluorescence was quenched by CoOOH nanoflakes. Due to the high quenching property of CoOOH nanoflakes as an efficient energy acceptor, a sensitive and selective sensing approach with satisfactory performance for T4 PNK sensing in a complex biological matrix has been successfully constructed and applied to the screening of inhibitors. The developed approach may potentially provide a new platform for further research, clinical diagnosis, and drug discovery of nucleotide kinase related diseases. PMID:27030367

  10. A cobalt oxyhydroxide nanoflake-based nanoprobe for the sensitive fluorescence detection of T4 polynucleotide kinase activity and inhibition

    NASA Astrophysics Data System (ADS)

    Cen, Yao; Yang, Yuan; Yu, Ru-Qin; Chen, Ting-Ting; Chu, Xia

    2016-04-01

    Phosphorylation of nucleic acids with 5'-OH termini catalyzed by polynucleotide kinase (PNK) is an inevitable process and has been implicated in many important cellular events. Here, we found for the first time that there was a significant difference in the adsorbent ability of cobalt oxyhydroxide (CoOOH) nanoflakes between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), which resulted in the fluorescent dye-labeled dsDNA still retaining strong fluorescence emission, while the fluorescence signal of ssDNA was significantly quenched by CoOOH nanoflakes. Based on this discovery, we developed a CoOOH nanoflake-based nanoprobe for the fluorescence sensing of T4 PNK activity and its inhibition by combining it with λ exonuclease cleavage reaction. In the presence of T4 PNK, dye-labeled dsDNA was phosphorylated and then cleaved by λ exonuclease to generate ssDNA, which could adsorb on the CoOOH nanoflakes and whose fluorescence was quenched by CoOOH nanoflakes. Due to the high quenching property of CoOOH nanoflakes as an efficient energy acceptor, a sensitive and selective sensing approach with satisfactory performance for T4 PNK sensing in a complex biological matrix has been successfully constructed and applied to the screening of inhibitors. The developed approach may potentially provide a new platform for further research, clinical diagnosis, and drug discovery of nucleotide kinase related diseases.Phosphorylation of nucleic acids with 5'-OH termini catalyzed by polynucleotide kinase (PNK) is an inevitable process and has been implicated in many important cellular events. Here, we found for the first time that there was a significant difference in the adsorbent ability of cobalt oxyhydroxide (CoOOH) nanoflakes between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), which resulted in the fluorescent dye-labeled dsDNA still retaining strong fluorescence emission, while the fluorescence signal of ssDNA was significantly quenched by Co

  11. Förster Resonance Energy Transfer-Based Self-Assembled Nanoprobe for Rapid and Sensitive Detection of Postoperative Pancreatic Fistula.

    PubMed

    Hamano, Nobuhito; Murata, Masaharu; Kawano, Takahito; Piao, Jing Shu; Narahara, Sayoko; Nakata, Ryosuke; Akahoshi, Tomohiko; Ikeda, Tetsuo; Hashizume, Makoto

    2016-03-01

    Postoperative pancreatic fistula (POPF) is the most serious and challenging complication following gastroenterological surgery. Activated pancreatic juice leaking from the organ remnant contains proteases that attack the surrounding tissue, potentially leading to severe inflammation, tissue necrosis, and fistula formation. However, it is difficult to observe pancreatic leakage during surgery and to evaluate the protease activity of leaked fluid at the patient's bedside. This report describes a protein nanocage-based protease ratiometric sensor comprising a pancreatic protease-sensitive small heat-shock protein (HSP) 16.5, which is a naturally occurring protein in Methanococcus jannaschii that forms a spherical structure by self-assembly of 24 subunits, and a chemically conjugated donor-acceptor dye pair for Förster resonance energy transfer (FRET). The HSP-FRET probe was constructed by subunit exchange of each dye-labeled engineered HSP, resulting in a spherical nanocage of approximately 10 nm in diameter, which exhibited very high stability against degradation in blood plasma and no remarkable toxicity in mice. The efficiency of FRET was found to depend on both the dye orientation and the acceptor/donor ratio. Pancreatic proteases, including trypsin, α-chymotrypsin, and elastase, were quantitatively analyzed by fluorescence recovery with high specificity using the HSP-FRET nanoprobe. Furthermore, the HSP-FRET nanoprobe was sufficiently sensitive to detect POPF in the pancreatic juice of patients using only the naked eye within 10 min. Thus, this novel nanoprobe is proposed as an effective and convenient tool for the detection of POPF and the visualization of activated pancreatic juice during gastroenterological surgery. PMID:26845508

  12. Chemiluminescence immunoassay for the rapid and sensitive detection of antibody against porcine parvovirus by using horseradish peroxidase/detection antibody-coated gold nanoparticles as nanoprobes.

    PubMed

    Zhou, Yuan; Zhou, Tao; Zhou, Rui; Hu, Yonggang

    2014-06-01

    A rapid, simple, facile, sensitive and enzyme-amplified chemiluminescence immunoassay (CLIA) method to detect antibodies against porcine parvovirus has been developed. Horseradish peroxidase (HRP) and the detection antibody were simultaneously co-immobilized on the surface of gold nanoparticles using the electrostatic method to form gold nanoparticle-based nanoprobes. This nanoprobe was employed in a sandwich-type CLIA, which enables CL signal readout from enzymatic catalysis and results in signal amplification. The presence of porcine parvovirus infection was determined in porcine parvovirus antibodies by measuring the CL intensity caused by the reaction of HRP-luminol with H2 O2 . Under optimal conditions, the obtained calibration plot for the standard positive serum was approximately linear within the dilution range of 1:80 to 1:5120. The limit of detection for the assay was 1:10,240 (S/N = 3), which is much lower than that typically achieved with an enzyme-linked immunosorbent assay (1:160; S/N = 3). A series of repeatability measurements using 1:320-fold diluted standard positive serum gave reproducible results with a relative standard deviation of 4.9% (n = 11). The ability of the immunosensor to analyze clinical samples was tested on porcine sera. The immunosensor had an efficiency of 90%, a sensitivity of 93.3%, and a specificity of 87.5% relative to the enzyme-linked immunosorbent assay results. PMID:23832716

  13. Gold nanoprobes-based resonance Rayleigh scattering assay platform: Sensitive cytosensing of breast cancer cells and facile monitoring of folate receptor expression.

    PubMed

    Cai, Huai-Hong; Pi, Jiang; Lin, Xiaoying; Li, Baole; Li, Aiqun; Yang, Pei-Hui; Cai, Jiye

    2015-12-15

    A rapid, facile assay for sensitive cytosensing of breast cancer cells should help to guide potential medical evaluation for breast cancer. Here, we report development of novel resonance Rayleigh scattering (RRS) cytosensor for cell recognitions and folate (FA) receptor expression analyses on living cells. Using FA-conjugated gold nanoparticles (FA-AuNPs) as nanoprobes, the constructed nanoprobes-assembled recognition interface could increase the binding capacity for cell recognition, amplify Au-aggregates-enhanced RRS signal, and then enhance the sensitivity for membrane antibody assay. FA-AuNPs-based RRS measurements enabled a distinct 34-times-enhancement in RRS intensities after incubation with human breast cancer cells, compared with normal cells. Receptor-targeted cytosensor was used to quantitatively detect human breast cancer MCF-7, liver cancer HepG2 and normal cells, which expressing different amount of FA receptor, respectively. The detection limit for MCF-7 cells was 12 cells/mL with good selectivity and reproducibility. Furthermore, the proposed cytosensor allowed for dynamic evaluation of FA receptor expression on different living cells after dihydroartemisinin stimulus. This assay platform shows the good potential for clinical diagnostics and antibody-targeted drug screening. PMID:26141102

  14. Shape-changing magnetic assemblies as high-sensitivity NMR-readable nanoprobes

    PubMed Central

    Zabow, G.; Dodd, S. J.; Koretsky, A. P.

    2015-01-01

    Fluorescent and plasmonic labels and sensors have revolutionized molecular biology, helping visualize in vitro cellular and biomolecular processes1–3. Increasingly, such probes are now designed to respond to wavelengths in the near infrared region, where reduced tissue autofluorescence and photon attenuation enable subsurface in vivo sensing4. But even in the near infrared, optical resolution and sensitivity decrease rapidly with increasing depth. Here we present a sensor design that obviates the need for optical addressability by operating in the NMR radio-frequency (RF) spectrum, where signal attenuation and distortion by tissue and biological media are negligible, where background interferences vanish, and where sensors can be spatially located using standard magnetic resonance imaging (MRI) equipment. The RF-addressable sensor assemblies presented here are comprised of pairs of magnetic disks spaced by swellable hydrogel material; they reversibly reconfigure in rapid response to chosen stimuli, to give geometry-dependent, dynamic NMR spectral signatures. Sensors can be made from biocompatible materials, are detectable down to low concentrations, and offer potential responsive NMR spectral shifts approaching a million times those of traditional magnetic resonance spectroscopies. Inherent adaptability should allow such shape-changing systems to measure numerous different environmental and physiological indicators, affording broadly generalizable, MRI-compatible, RF analogues to optically-based probes for use in basic chemical, biological and medical research. PMID:25778701

  15. Shape-changing magnetic assemblies as high-sensitivity NMR-readable nanoprobes.

    PubMed

    Zabow, G; Dodd, S J; Koretsky, A P

    2015-04-01

    Fluorescent and plasmonic labels and sensors have revolutionized molecular biology, helping visualize cellular and biomolecular processes. Increasingly, such probes are now being designed to respond to wavelengths in the near-infrared region, where reduced tissue autofluorescence and photon attenuation enable subsurface in vivo sensing. But even in the near-infrared region, optical resolution and sensitivity decrease rapidly with increasing depth. Here we present a sensor design that obviates the need for optical addressability by operating in the nuclear magnetic resonance (NMR) radio-frequency spectrum, where signal attenuation and distortion by tissue and biological media are negligible, where background interferences vanish, and where sensors can be spatially located using standard magnetic resonance imaging (MRI) equipment. The radio-frequency-addressable sensor assemblies presented here comprise pairs of magnetic disks spaced by swellable hydrogel material; they reversibly reconfigure in rapid response to chosen stimuli, to give geometry-dependent, dynamic NMR spectral signatures. The sensors can be made from biocompatible materials, are themselves detectable down to low concentrations, and offer potential responsive NMR spectral shifts that are close to a million times greater than those of traditional magnetic resonance spectroscopies. Inherent adaptability should allow such shape-changing systems to measure numerous different environmental and physiological indicators, thus providing broadly generalizable, MRI-compatible, radio-frequency analogues to optically based probes for use in basic chemical, biological, medical and engineering research. PMID:25778701

  16. Shape-changing magnetic assemblies as high-sensitivity NMR-readable nanoprobes

    NASA Astrophysics Data System (ADS)

    Zabow, G.; Dodd, S. J.; Koretsky, A. P.

    2015-04-01

    Fluorescent and plasmonic labels and sensors have revolutionized molecular biology, helping visualize cellular and biomolecular processes. Increasingly, such probes are now being designed to respond to wavelengths in the near-infrared region, where reduced tissue autofluorescence and photon attenuation enable subsurface in vivo sensing. But even in the near-infrared region, optical resolution and sensitivity decrease rapidly with increasing depth. Here we present a sensor design that obviates the need for optical addressability by operating in the nuclear magnetic resonance (NMR) radio-frequency spectrum, where signal attenuation and distortion by tissue and biological media are negligible, where background interferences vanish, and where sensors can be spatially located using standard magnetic resonance imaging (MRI) equipment. The radio-frequency-addressable sensor assemblies presented here comprise pairs of magnetic disks spaced by swellable hydrogel material; they reversibly reconfigure in rapid response to chosen stimuli, to give geometry-dependent, dynamic NMR spectral signatures. The sensors can be made from biocompatible materials, are themselves detectable down to low concentrations, and offer potential responsive NMR spectral shifts that are close to a million times greater than those of traditional magnetic resonance spectroscopies. Inherent adaptability should allow such shape-changing systems to measure numerous different environmental and physiological indicators, thus providing broadly generalizable, MRI-compatible, radio-frequency analogues to optically based probes for use in basic chemical, biological, medical and engineering research.

  17. SHG nanoprobes: advancing harmonic imaging in biology.

    PubMed

    Dempsey, William P; Fraser, Scott E; Pantazis, Periklis

    2012-05-01

    Second harmonic generating (SHG) nanoprobes have recently emerged as versatile and durable labels suitable for in vivo imaging, circumventing many of the inherent drawbacks encountered with classical fluorescent probes. Since their nanocrystalline structure lacks a central point of symmetry, they are capable of generating second harmonic signal under intense illumination - converting two photons into one photon of half the incident wavelength - and can be detected by conventional two-photon microscopy. Because the optical signal of SHG nanoprobes is based on scattering, rather than absorption as in the case of fluorescent probes, they neither bleach nor blink, and the signal does not saturate with increasing illumination intensity. When SHG nanoprobes are used to image live tissue, the SHG signal can be detected with little background signal, and they are physiologically inert, showing excellent long-term photostability. Because of their photophysical properties, SHG nanoprobes provide unique advantages for molecular imaging of living cells and tissues with unmatched sensitivity and temporal resolution. PMID:22392481

  18. Gold nanoprobes for theranostics

    PubMed Central

    Panchapakesan, Balaji; Book-Newell, Brittany; Sethu, Palaniappan; Rao, Madhusudhana; Irudayaraj, Joseph

    2011-01-01

    Gold nanoprobes have become attractive diagnostic and therapeutic agents in medicine and life sciences research owing to their reproducible synthesis with atomic level precision, unique physical and chemical properties, versatility of their morphologies, flexibility in functionalization, ease of targeting, efficiency in drug delivery and opportunities for multimodal therapy. This review highlights some of the recent advances and the potential for gold nanoprobes in theranostics. PMID:22122586

  19. Plasmonic nanoprobes for SERS biosensing and bioimaging

    PubMed Central

    Vo-Dinh, Tuan; Wang, Hsin-Neng; Scaffidi, Jonathan

    2013-01-01

    This article provides an overview of the development and application of plasmonic nanoprobes developed in our laboratory for biosensing and bioimaging. We describe the use of plasmonics surface-enhanced Raman scattering (SERS) gene probes for the detection of diseases using DNA hybridization to target biospecies (HIV gene, breast cancer genes etc.). For molecular imaging, we describe a hyperspectral surface-enhanced Raman imaging (HSERI) system that combines imaging capabilities with SERS detection to identify cellular components using Raman dye-labeled silver nanoparticles in cellular systems The detection of specific target DNA sequences associated with breast cancer using “molecular sentinel” nanoprobes and the use of a plasmonic nanosensor to monitor pH in single cells are presented and discussed. Plasmonic nanosensors and nanoprobes have been developed as sensitive and selective tolls for environmental monitoring, cellular biosensing, medical diagnostics and high throughput screnning. PMID:19517422

  20. Gold nanoprobe functionalized with specific fusion protein selection from phage display and its application in rapid, selective and sensitive colorimetric biosensing of Staphylococcus aureus.

    PubMed

    Liu, Pei; Han, Lei; Wang, Fei; Petrenko, Valery A; Liu, Aihua

    2016-08-15

    Staphylococcus aureus (S. aureus) is one of the most ubiquitous pathogens in public healthcare worldwide. It holds great insterest in establishing robust analytical method for S. aureus. Herein, we report a S. aureus-specific recognition element, isolated from phage monoclone GQTTLTTS, which was selected from f8/8 landscape phage library against S. aureus in a high-throughput way. By functionalizing cysteamine (CS)-stabilized gold nanoparticles (CS-AuNPs) with S. aureus-specific pVIII fusion protein (fusion-pVIII), a bifunctional nanoprobe (CS-AuNPs@fusion-pVIII) for S. aureus was developed. In this strategy, the CS-AuNPs@fusion-pVIII could be induced to aggregate quickly in the presence of target S. aureus, resulting in a rapid colorimetric response of gold nanoparticles. More importantly, the as-designed probe exhibited excellent selectivity over other bacteria. Thus, the CS-AuNPs@fusion-pVIII could be used as the indicator of target S. aureus. This assay can detect as low as 19CFUmL(-1)S. aureus within 30min. Further, this approach can be applicable to detect S. aureus in real water samples. Due to its sensitivity, specificity and rapidness, this proposed method is promising for on-site testing of S. aureus without using any costly instruments. PMID:27085951

  1. Magnetomotive Molecular Nanoprobes

    PubMed Central

    John, Renu; Boppart, Stephen A.

    2012-01-01

    Tremendous developments in the field of biomedical imaging in the past two decades have resulted in the transformation of anatomical imaging to molecular-specific imaging. The main approaches towards imaging at a molecular level are the development of high resolution imaging modalities with high penetration depths and increased sensitivity, and the development of molecular probes with high specificity. The development of novel molecular contrast agents and their success in molecular optical imaging modalities have lead to the emergence of molecular optical imaging as a more versatile and capable technique for providing morphological, spatial, and functional information at the molecular level with high sensitivity and precision, compared to other imaging modalities. In this review, we discuss a new class of dynamic contrast agents called magnetomotive molecular nanoprobes for molecular-specific imaging. Magnetomotive agents are superparamagnetic nanoparticles, typically iron-oxide, that are physically displaced by the application of a small modulating external magnetic field. Dynamic phase-sensitive position measurements are performed using any high resolution imaging modality, including optical coherence tomography (OCT), ultrasonography, or magnetic resonance imaging (MRI). The dynamics of the magnetomotive agents can be used to extract the biomechanical tissue properties in which the nanoparticles are bound, and the agents can be used to deliver therapy via magnetomotive displacements to modulate or disrupt cell function, or hyperthermia to kill cells. These agents can be targeted via conjugation to antibodies, and in vivo targeted imaging has been shown in a carcinogen-induced rat mammary tumor model. The iron-oxide nanoparticles also exhibit negative T2 contrast in MRI, and modulations can produce ultrasound imaging contrast for multimodal imaging applications. PMID:21517766

  2. Nanoprobes with optical tweezers for biological applications

    NASA Astrophysics Data System (ADS)

    Kendrick, Mark; McIntyre, David; Ostroverkhova, Oksana; Bychkova, Valeriya; Shvarev, Alexey

    2010-03-01

    We explore the use of sub-micron sized particles in optical tweezer traps as nanoprobes in microfluidic devices and biological cells. For applications that require high spatial resolution, the ability to suppress the particle's natural Brownian motion down to the nanometer or sub-nanometer scales is essential. However, the optical tweezer force scales with the volume of the particle making it difficult to confine and manipulate nanometer sized particles with high precision. To overcome this difficulty, we explore the possibility of using optically resonant particles as nanoprobes. The resonant particles should experience an increase in the optical tweezer force at wavelengths on the red side of the absorption resonance, resulting in a tighter confinement. We explore this phenomenon by measuring the trapping force acting on resonant particles (dye-filled polymeric and metallic particles) as a function of trapping laser wavelength and discuss the feasibility of using them as a high spatial resolution probe. In addition, we use similar particles as optically trapped nanoprobes to monitor temporal and spatial differences in an inhomogeneous environment; for example, we have developed pH-sensitive fluorescent nanoprobes for biological applications.

  3. Plasmonic nanoprobes: from chemical sensing to medical diagnostics and therapy

    NASA Astrophysics Data System (ADS)

    Vo-Dinh, Tuan; Fales, Andrew M.; Griffin, Guy D.; Khoury, Christopher G.; Liu, Yang; Ngo, Hoan; Norton, Stephen J.; Register, Janna K.; Wang, Hsin-Neng; Yuan, Hsiangkuo

    2013-10-01

    This article provides an overview of the development and applications of plasmonics-active nanoprobes in our laboratory for chemical sensing, medical diagnostics and therapy. Molecular Sentinel nanoprobes provide a unique tool for DNA/RNA biomarker detection both in a homogeneous solution or on a chip platform for medical diagnostics. The possibility of combining spectral selectivity and high sensitivity of the surface-enhanced Raman scattering (SERS) process with the inherent molecular specificity of nanoprobes provides an important multiplex diagnostic modality. Gold nanostars can provide an excellent multi-modality platform, combining two-photon luminescence with photothermal therapy as well as Raman imaging with photodynamic therapy. Several examples of optical detection using SERS and photonics-based treatments are presented to illustrate the usefulness and potential of the plasmonic nanoprobes for theranostics, which seamlessly combines diagnostics and therapy.

  4. An upconversion luminescence nanoprobe for the ultrasensitive detection of hyaluronidase.

    PubMed

    Wang, Zhe; Li, Xiaohua; Song, Yanchao; Li, Lihong; Shi, Wen; Ma, Huimin

    2015-06-01

    A new upconversion luminescence nanoprobe for the detection of hyaluronidase has been developed by coupling the hyaluronic acid-bearing upconversion fluorescence nanoparticles (HA-UCNPs) with poly(m-phenylenediamine) (PMPD) nanospheres via covalent linkage. The nanoprobe alone exhibits an extremely low background signal owing to the effective fluorescence quenching by electron-rich PMPD and the near-infrared excitation characteristic (λex = 980 nm) of HA-UCNPs; upon reaction with hyaluronidase, however, a more than 31-fold fluorescence enhancement is produced. Compared with the corresponding nanosystem assembled via physical adsorption, the prepared nanoprobe shows a largely increased stability and a much higher signal-to-background ratio, which offers an ultrasensitive assay for hyaluronidase, with a detection limit of 0.6 ng/mL. The nanoprobe has been successfully used to determine hyaluronidase in human serum samples from both colorectal cancer patients and healthy people, disclosing that the serum hyaluronidase level in colorectal cancer patients is roughly 3 times higher than that in healthy people. Furthermore, the nanoprobe has also been employed to study the activity change of hyaluronidase affected by different concentrations of arsenate (a potential carcinogen), and the results show that even a low dosage of arsenate (50 μg/L) can raise the activity of hyaluronidase by about one-third, revealing the relationship between arsenate and the enzyme. The proposed method is not only simple but also highly sensitive, making it useful to assay hyaluronidase in relevant clinical samples. PMID:25947627

  5. Biomolecular recognition and detection using gold-based nanoprobes

    NASA Astrophysics Data System (ADS)

    Crew, Elizabeth

    The ability to control the biomolecular interactions is important for developing bioanalytical probes used in biomolecule and biomarker detections. This work aims at a fundamental understanding of the interactions and reactivities involving DNA, miRNA, and amino acids using gold-based nanoparticles as nanoprobes, which has implications for developing new strategies for the early detection of diseases, such as cancer, and controlled delivery of drugs. Surface modifications of the nanoprobes with DNA, miRNA, and amino acids and the nanoprobe directed biomolecular reactivities, such as complementary-strand binding, enzymatic cutting and amino acid interactions, have been investigated. Among various analytical techniques employed for the analysis of the biomolecule-nanoprobe interactions, surface enhanced Raman scattering spectroscopy (SERS) has been demonstrated to provide a powerful tool for real time monitoring of the DNA assembly and enzymatic cutting processes in solutions. This demonstration harnesses the "hot-spot" characteristic tuned by the interparticle biomolecular-regulated interactions and distances. The assembly of gold nanoparticles has also been exploited as sensing thin films on chemiresistor arrays for the detection of volatile organic compounds, including biomarker molecules associated with diabetes. Important findings of the nanoprobes in delivering miRNA to cells, detecting DNA hybridization kinetics, discerning chiral recognition with enantiomeric cysteines, and sensing biomarker molecules with the nanostructured thin films will be discussed, along with their implications to enhancing sensitivity, selectivity and limits of detection.

  6. Multifunctional imaging nanoprobes

    PubMed Central

    Jarzyna, Peter A.; Gianella, Anita; Skajaa, Torjus; Knudsen, Gitte; Deddens, Lisette H.; Cormode, David P.; Fayad, Zahi A.; Mulder, Willem J. M.

    2011-01-01

    Multifunctional imaging nanoprobes have proven to be of great value in the research of pathological processes, as well as the assessment of the delivery, fate, and therapeutic potential of encapsulated drugs. Moreover, such probes may potentially support therapy schemes by the exploitation of their own physical properties, e.g., through thermal ablation. This review will present four classes of nanoparticulate imaging probes used in this area: multifunctional probes (1) that can be tracked with at least three different and complementary imaging techniques, (2) that carry a drug and have bimodal imaging properties, (3) that are employed for nucleic acid delivery and imaging, and (4) imaging probes with capabilities that can be used for thermal ablation. We will highlight several examples where the suitable combination of different (bio)materials like polymers, inorganic nanocrystals, fluorophores, proteins/peptides, and lipids can be tailored to manufacture multifunctional probes to accomplish nanomaterials of each of the aforementioned classes. Moreover, it will be demonstrated how multimodality imaging approaches improve our understanding of in vivo nanoparticle behavior and efficacy at different levels, ranging from the subcellular level to the whole body. PMID:20039335

  7. A symmetrical fluorous dendron-cyanine dye-conjugated bimodal nanoprobe for quantitative 19F MRI and NIR fluorescence bioimaging.

    PubMed

    Wang, Zhe; Yue, Xuyi; Wang, Yu; Qian, Chunqi; Huang, Peng; Lizak, Marty; Niu, Gang; Wang, Fu; Rong, Pengfei; Kiesewetter, Dale O; Ma, Ying; Chen, Xiaoyuan

    2014-08-01

    (19)F MRI and optical imaging are two powerful noninvasive molecular imaging modalities in biomedical applications. (19)F MRI has great potential for high resolution in vivo imaging, while fluorescent probes enable ultracontrast cellular/tissue imaging with high accuracy and sensitivity. A bimodal nanoprobe is developed, integrating the merits of (19)F MRI and fluorescence imaging into a single synthetic molecule, which is further engineered into nanoprobe, by addressing shortcomings of conventional contrast agents to explore the quantitative (19)F MRI and fluorescence imaging and cell tracking. Results show that this bimodal imaging nanoprobe presents high correlation of (19)F MR signal and NIR fluorescence intensity in vitro and in vivo. Additionally, this nanoprobe enables quantitative (19)F MR analysis, confirmed by a complementary fluorescence analysis. This unique feature can hardly be obtained by traditional (19)F MRI contrast agents. It is envisioned that this nanoprobe can hold great potential for quantitative and sensitive multi-modal molecular imaging. PMID:24789108

  8. Quantum dot-labeled aptamer nanoprobes specifically targeting glioma cells

    NASA Astrophysics Data System (ADS)

    Chen, Xue-Chai; Deng, Yu-Lin; Lin, Yi; Pang, Dai-Wen; Qing, Hong; Qu, Feng; Xie, Hai-Yan

    2008-06-01

    Two new techniques, aptamer-based specific recognition and quantum dot (QD)-based fluorescence labeling, are becoming increasingly important in biosensing. In this study, these two techniques have been coupled together to construct a new kind of fluorescent QD-labeled aptamer (QD-Apt) nanoprobe by conjugating GBI-10 aptamer to the QD surface. GBI-10 is a single-stranded DNA (ssDNA) aptamer for tenascin-C, which distributes on the surface of glioma cells as a dominant extracellular matrix protein. The QD-Apt nanoprobe can recognize the tenascin-C on the human glioma cell surface, which will be helpful for the development of new convenient and sensitive in vitro diagnostic assays for glioma. The QD-Apt nanoprobe has particular features such as strong fluorescence, stability, monodispersity and uniformity. In addition, this probe preparation method is universal, so it is expected to provide a new type of stable nanoprobe for high-throughput and fast biosensing detection and bioimaging. New methods for real-time and dynamic tracking and imaging can be accordingly developed.

  9. Observation of Molecular Diffusion in Polyelectrolyte-Wrapped SERS Nanoprobes

    PubMed Central

    2015-01-01

    The popularity of nanotechnology-based sensing technologies has rapidly expanded within the past decade. Surface-enhanced Raman spectroscopy (SERS) is one such technique capable of chemically specific and highly sensitive measurements. The careful preparation of SERS-active nanoprobes is immensely vital for biological applications where nanoprobes are exposed to harsh ionic and protein rich microenvironments. Encapsulation of optical reporter molecules via layer-by-layer (LbL) polyelectrolyte wrapping is an emerging technique that also permits facile modification of surface chemistry and charge. LbL wrapping can be performed within a few hours and does not require the use of organic solvents or hazardous silanes. Nonetheless, the stability of its products requires further characterization and analysis. In this study, Raman-active methylene blue molecules were electrostatically encapsulated within alternating layers of cationic and anionic polyelectrolytes surrounding gold nanospheres. We observed molecular diffusion of methylene blue through polyelectrolyte layers by monitoring the change in SERS intensity over a period of more than 5 weeks. To minimize diffusion and improve the long-term storage stability of our nanoprobes, two additional nanoprobe preparation techniques were performed: thiol coating and cross-linking of the outer polyelectrolyte layer. In both cases, molecular diffusion is significantly diminished. PMID:24998291

  10. Cost-Sensitive Local Binary Feature Learning for Facial Age Estimation.

    PubMed

    Lu, Jiwen; Liong, Venice Erin; Zhou, Jie

    2015-12-01

    In this paper, we propose a cost-sensitive local binary feature learning (CS-LBFL) method for facial age estimation. Unlike the conventional facial age estimation methods that employ hand-crafted descriptors or holistically learned descriptors for feature representation, our CS-LBFL method learns discriminative local features directly from raw pixels for face representation. Motivated by the fact that facial age estimation is a cost-sensitive computer vision problem and local binary features are more robust to illumination and expression variations than holistic features, we learn a series of hashing functions to project raw pixel values extracted from face patches into low-dimensional binary codes, where binary codes with similar chronological ages are projected as close as possible, and those with dissimilar chronological ages are projected as far as possible. Then, we pool and encode these local binary codes within each face image as a real-valued histogram feature for face representation. Moreover, we propose a cost-sensitive local binary multi-feature learning method to jointly learn multiple sets of hashing functions using face patches extracted from different scales to exploit complementary information. Our methods achieve competitive performance on four widely used face aging data sets. PMID:26415174

  11. Rare Earth Nanoprobes for Functional Biomolecular Imaging and Theranostics

    PubMed Central

    Naczynski, Dominik J.; Tan, Mei Chee; Riman, Richard E.; Moghe, Prabhas V.

    2014-01-01

    Contrast agents designed to visualize the molecular mechanisms underlying cancer pathogenesis and progression have deepened our understanding of disease complexity and accelerated the development of enhanced drug strategies targeted to specific biochemical pathways. For the next generation probes and imaging systems to be viable, they must exhibit enhanced sensitivity and robust quantitation of morphologic and contrast features, while offering the ability to resolve the disease-specific molecular signatures that may be critical to reconstitute a more comprehensive portrait of pathobiology. This feature article provides an overview on the design and advancements of emerging biomedical optical probes in general and evaluates the promise of rare earth nanoprobes, in particular, for molecular imaging and theranostics. Combined with new breakthroughs in nanoscale probe configurations, and improved dopant compositions, and multimodal infrared optical imaging, rare-earth nanoprobes can be used to address a wide variety of biomedical challenges, including deep tissue imaging, real-time drug delivery tracking and multispectral molecular profiling. PMID:24921049

  12. Partially reduced graphene oxide as highly efficient DNA nanoprobe.

    PubMed

    Wang, Yan-Hong; Deng, Hao-Hua; Liu, Yin-Huan; Shi, Xiao-Qiong; Liu, Ai-Lin; Peng, Hua-Ping; Hong, Guo-Lin; Chen, Wei

    2016-06-15

    This work investigates the effect of reduction degree on graphene oxide (GO)-DNA interaction and the fluorescence quenching mechanism. Partial reduced graphene oxide (pRGO), which maintains well water-dispersibility, is synthesized using a mild reduction method by incubating GO suspension under alkaline condition at room temperature. The fluorescence quenching enhances with the restoration degree of sp(2) carbon bonds and follows the static quenching mechanism. The binding constant values imply that pRGO has much stronger affinity with ssDNA than GO. Utilizing this highly efficient nanoprobe, a universal sensing strategy is proposed for homogeneous detection of DNA. Compared with the reported GO-based DNA, this present strategy has obvious advantages such as requirement of low nanoprobe dosage, significantly reduced background, fast fluorescence quenching, and improved sensitivity. Even without any amplification process, the limit of detection can reach as low as 50 pM. PMID:26826548

  13. Targeting Angiogenesis Using a C-Type Atrial Natriuretic Factor–Conjugated Nanoprobe and PET

    PubMed Central

    Liu, Yongjian; Pressly, Eric D.; Abendschein, Dana R.; Hawker, Craig J.; Woodard, Geoffrey E.; Woodard, Pamela K.; Welch, Michael J.

    2014-01-01

    Sensitive, specific, and noninvasive detection of angiogenesis would be helpful in discovering new strategies for the treatment of cardiovascular diseases. Recently, we reported the 64Cu-labeled C-type atrial natriuretic factor (CANF) fragment for detecting the upregulation of natriuretic peptide clearance receptor (NPR-C) with PET on atherosclerosis-like lesions in an animal model. However, it is unknown whether NPR-C is present and overexpressed during angiogenesis. The goal of this study was to develop a novel CANF-integrated nanoprobe to prove the presence of NPR-C and offer sensitive detection with PET during development of angiogenesis in mouse hind limb. Methods We prepared a multifunctional, core-shell nanoparticle consisting of DOTA chelators attached to a poly(methyl methacrylate) core and CANF-targeting moieties attached to poly(ethylene glycol) chain ends in the shell of the nanoparticle. Labeling of this nanoparticle with 64Cu yielded a high-specific-activity nanoprobe for PET imaging NPR-C receptor in a mouse model of hind limb ischemia–induced angiogenesis. Histology and immunohistochemistry were performed to assess angiogenesis development and NPR-C localization. Results 15O-H2O imaging showed blood flow restoration in the previously ischemic hind limb, consistent with the development of angiogenesis. The targeted DOTA-CANF-comb nanoprobe showed optimized pharmacokinetics and biodistribution. PET imaging demonstrated significantly higher tracer accumulation for the targeted DOTA-CANF-comb nanoprobe than for either the CANF peptide tracer or the nontargeted control nanoprobe (P < 0.05, both). Immunohistochemistry confirmed NPR-C upregulation in the angiogenic lesion with colocalization in both endothelial and smooth muscle cells. PET and immunohistochemistry competitive receptor blocking verified the specificity of the targeted nanoprobe to NPR-C receptor. Conclusion As evidence of its translational potential, this customized DOTA

  14. Poly(m-phenylenediamine)-based fluorescent nanoprobe for ultrasensitive detection of matrix metalloproteinase 2.

    PubMed

    Wang, Zhe; Li, Xiaohua; Feng, Duan; Li, Lihong; Shi, Wen; Ma, Huimin

    2014-08-01

    A novel fluorescence nanoprobe for the detection of matrix metalloproteinase 2 (MMP2) has been developed by engineering the fluorescein isothiocyanate-labeled peptide onto the surface of poly(m-phenylenediamine) (PMPD) nanoparticles through covalent linkage. The nanoprobe itself displays a low background signal due to the effective fluorescence quenching by electron-rich PMPD, but its reaction with MMP2 causes 11-fold fluorescence enhancement. Compared with similar fluorescence nanosystems for MMP2 assembled through physical adsorption, the as-prepared nanoprobe is significantly more stable and displays a strikingly higher signal-to-background ratio, which leads to a high sensitivity for MMP2 assay, with a detection limit of 32 pM. Most notably, the nanoprobe has been successfully applied to determine MMP2 in human serum samples, demonstrating that the MMP2 level in serum from colorectal cancer (CRC) patients is 2 times higher than that from healthy people. Moreover, the nanoprobe has also been used to monitor MMP2 secreted by CRC cells that were grown under normoxic and hypoxic conditions, respectively, and the results show that the cells under hypoxic conditions produce higher level of MMP2 than those under normoxic conditions. Our method is simple and can offer a highly sensitive detection of MMP2 in relevant clinical samples. PMID:25029076

  15. Two-Dimensional Optoelectronic Graphene Nanoprobes for Neural Nerwork

    NASA Astrophysics Data System (ADS)

    Hong, Tu; Kitko, Kristina; Wang, Rui; Zhang, Qi; Xu, Yaqiong

    2014-03-01

    Brain is the most complex network created by nature, with billions of neurons connected by trillions of synapses through sophisticated wiring patterns and countless modulatory mechanisms. Current methods to study the neuronal process, either by electrophysiology or optical imaging, have significant limitations on throughput and sensitivity. Here, we use graphene, a monolayer of carbon atoms, as a two-dimensional nanoprobe for neural network. Scanning photocurrent measurement is applied to detect the local integration of electrical and chemical signals in mammalian neurons. Such interface between nanoscale electronic device and biological system provides not only ultra-high sensitivity, but also sub-millisecond temporal resolution, owing to the high carrier mobility of graphene.

  16. Quantifying the microvascular origin of BOLD-fMRI from first principles with two-photon microscopy and an oxygen-sensitive nanoprobe.

    PubMed

    Gagnon, Louis; Sakadžić, Sava; Lesage, Frédéric; Musacchia, Joseph J; Lefebvre, Joël; Fang, Qianqian; Yücel, Meryem A; Evans, Karleyton C; Mandeville, Emiri T; Cohen-Adad, Jülien; Polimeni, Jonathan R; Yaseen, Mohammad A; Lo, Eng H; Greve, Douglas N; Buxton, Richard B; Dale, Anders M; Devor, Anna; Boas, David A

    2015-02-25

    The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences. PMID:25716864

  17. Carbon Dots Embedded Magnetic Nanoparticles @Chitosan @Metal Organic Framework as a Nanoprobe for pH Sensitive Targeted Anticancer Drug Delivery.

    PubMed

    Chowdhuri, Angshuman Ray; Singh, Tanya; Ghosh, Sudip Kumar; Sahu, Sumanta Kumar

    2016-07-01

    Recently, nanoscale metal organic frameworks (NMOFs) have been demonstrated as a promising carrier for drug delivery, as they possess many advantages like large surface area, high porosity, and tunable functionality. However, there are no reports about the functionalization of NMOFs, which combines cancer-targeted drug delivery/imaging, magnetic property, high drug loading content, and pH-sensitive drug release into one system. Existing formulations for integrating target molecules into NMOF are based on multistep synthetic processes. However, in this study, we report an approach that combines NMOF (IRMOF-3) synthesis and target molecule (Folic acid) encapsulation on the surface of chitosan modified magnetic nanoparticles in a single step. A noticeable feature of chitosan is control and pH responsive drug release for several days. More importantly, doxorubicin (DOX) was incorporated into magnetic NMOF formulation and showed high drug loading (1.63 g DOX g(-1) magnetic NMOFs). To demonstrate the optical imaging, carbon dots (CDs) are encapsulated into the synthesized magnetic NMOF, thereby endowing fluorescence features to the nanoparticles. These folate targeted magnetic NMOF possess more specific cellular internalization toward folate-overexpressed cancer (HeLa) cells in comparison to normal (L929) cells. PMID:27305490

  18. Neurotoxin-conjugated upconversion nanoprobes for direct visualization of tumors under near-infrared irradiation.

    PubMed

    Yu, Xue-Feng; Sun, Zhengbo; Li, Min; Xiang, Yang; Wang, Qu-Quan; Tang, Fenfen; Wu, Yingliang; Cao, Zhijian; Li, Wenxin

    2010-11-01

    We report the development of neurotoxin-mediated upconversion nanoprobes for tumor targeting and visualization in living animals. The nanoprobes were synthesized by preparing polyethylenimine-coated hexagonal-phase NaYF(4):Yb,Er/Ce nanoparticles and conjugating them with recombinant chlorotoxin, a typical peptide neurotoxin that could bind with high specificity to many types of cancer cells. Nanoprobes that specifically targeted glioma cells were visualized by laser scanning upconversion fluorescence microscopy. Good probe biocompatibility was displayed with cellular and animal toxicity determinations. Animal studies were performed using Balb-c nude mice injected intravenously with the nanoprobes. The obtained high-contrast images demonstrated highly specific tumor binding and direct tumor visualization with bright red fluorescence under 980-nm near-infrared irradiation. The high sensitivity and high specificity of the neurotoxin-mediated upconversion nanoprobes and the simplification of the required optical device for tumor visualization suggest an approach that may help improve the effectiveness of the diagnostic and therapeutic modalities available for tumor patients. PMID:20728213

  19. Scanning Kelvin nanoprobe detection in materials science and biochemical analysis.

    PubMed

    Cheran, Larisa-Emilia; Sadeghi, Saman; Thompson, Michael

    2005-12-01

    The Kelvin nanoprobe is an extremely sensitive instrument capable of discerning subtle molecular interactions using vibrating electromagnetic and acoustic fields. It is based on the measurement of a fundamental material property, the work function. Modulation of this substrate parameter is caused by the adsorption or desorption of molecules, oxidation, corrosion, contamination, mechanical stress, illumination, temperature changes, electrostatic charging, surface treatment, attached dipolar structures and/or the immobilization of biomolecules. The present article explains the general principles of the method and offers an indication of the wide range of possible applications, with an emphasis on potential use in the biotechnological arena. PMID:16284653

  20. Sensitivity-based adaptive learning rules for binary feedforward neural networks.

    PubMed

    Zhong, Shuiming; Zeng, Xiaoqin; Wu, Shengli; Han, Lixin

    2012-03-01

    This paper proposes a set of adaptive learning rules for binary feedforward neural networks (BFNNs) by means of the sensitivity measure that is established to investigate the effect of a BFNN's weight variation on its output. The rules are based on three basic adaptive learning principles: the benefit principle, the minimal disturbance principle, and the burden-sharing principle. In order to follow the benefit principle and the minimal disturbance principle, a neuron selection rule and a weight adaptation rule are developed. Besides, a learning control rule is developed to follow the burden-sharing principle. The advantage of the rules is that they can effectively guide the BFNN's learning to conduct constructive adaptations and avoid destructive ones. With these rules, a sensitivity-based adaptive learning (SBALR) algorithm for BFNNs is presented. Experimental results on a number of benchmark data demonstrate that the SBALR algorithm has better learning performance than the Madaline rule II and backpropagation algorithms. PMID:24808553

  1. Self-illuminating nanoprobe for in vivo imaging of cancers over-expressing the folate receptor

    NASA Astrophysics Data System (ADS)

    Miller, Steven C.; Beviglia, Lucia; Yeung, Pete; Bhattacharyya, Sukanta; Sobek, Daniel

    2012-03-01

    New in vivo imaging reagents with increased sensitivity and penetration depth are needed to advance our understanding of metastases and accelerate the development of therapeutics. The folate receptor (FR) is a promising imaging target that is up-regulated in many human carcinomas, including cancers of the ovary, breast, pancreas, endometrium, lungs, kidneys, colon, brain, and myeloid cells. Zymera has developed a self-illuminating Bioluminescence Resonance Energy Transfer Quantum Dot (BRET-Qdot) nanoprobe conjugated with folate (BQ-Folate) for in vivo imaging of cancers overexpressing FR. BQ-Folate is a novel nanoprobe formed by co-conjugating Renilla reniformis luciferase enzyme and folate to near-infrared (NIR) emitting quantum dots. The luciferase substrate, coelenterazine, activates the BQ-Folate nanoprobe generating luminescence emission in the near-infrared (NIR) region (655 nm) for increased sensitivity and penetration depth. Because BQ-Folate requires no external light source for light emission, it has significant advantages for challenging in vivo preclinical optical imaging applications, such as the detection of early stage metastases. Zymera and OncoMed Pharmaceuticals have demonstrated that in vivo imaging with the BQ-Folate nanoprobe detected the primary tumor and early stage metastases in an orthotopic NOD/SCID mouse model of human pancreatic cancer.

  2. Off-Resonance Saturation MRI of Superparamagnetic Nanoprobes: Theoretical Models and Experimental Validations

    PubMed Central

    Khemtong, Chalermchai; Togao, Osamu; Ren, Jimin; Kessinger, Chase W.; Takahashi, Masaya; Sherry, A. Dean; Gao, Jinming

    2011-01-01

    Off-resonance saturation (ORS) is a new magnetic resonance imaging (MRI) method that has shown greatly improved contrast sensitivity for the detection of cancer-specific biomarkers by superparamagnetic nanoprobes in vivo. However, quantitative understanding of the ORS contrast mechanism and its dependence on the structural parameters of superparamagnetic nanoprobes are still lacking. Here we propose a quantitative model of ORS contrast and its experimental validation by superparamagnetic polymeric micelles (SPPM) with precisely controlled structural properties. Size selected, monodisperse Fe3O4 nanoparticles (6.1 ± 0.2 nm) were used to form a series of SPPM nanoprobes with specifically controlled corona thickness using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxypoly(ethylene glycol) (DSPE-PEG) with different PEG molecular weights. Transmission electron microscopy and dynamic light scattering showed that SPPM were uniform in size. The average hydrodynamic diameters of SPPM with PEG lengths of 0.55, 1, 2, and 5 kD were 16.6 ± 2.8, 18.4 ± 2.9, 24.1 ± 3.4, and 28.9 ± 3.4 nm, respectively. MRI experiments at 7T determined that r2 values of SPPM with 0.55, 1, 2, and 5 kD PEG as corona were 201 ± 3, 136 ± 8, 107 ± 5, and 108 ± 8 Fe mM-1s-1, respectively. ORS intensity from Z-spectra of SPPM showed a significant correlation with the inverse of T2 relaxation rates (1/T2, s-1) of the SPPM nanoprobes regardless of the PEG corona thickness. These data provide the fundamental understanding of the structure-property relationships between the SPPM nanostructures and ORS sensitivity, which offers useful mechanistic insights for the future improvement of SPPM nanoprobes in cancer molecular imaging applications. PMID:21277813

  3. Counter electrodes from binary ruthenium selenide alloys for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Li, Pinjiang; Cai, Hongyuan; Tang, Qunwei; He, Benlin; Lin, Lin

    2014-12-01

    Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, cost-effectiveness, relatively high efficiency, and easy fabrication. However, the reduction of fabrication cost without sacrifice of power conversion efficiencies of the DSSCs is a golden rule for their commercialization. Here we design a new binary ruthenium selenide (Ru-Se) alloy counter electrodes (CEs) by a low-temperature hydrothermal reduction method. The electrochemical behaviors are evaluated by cyclic voltammogram, electrochemical impedance, and Tafel measurements, giving an optimized Ru/Se molar ratio of 1:1. The DSSC device with RuSe alloy CE achieves a power conversion efficiency of 7.15%, which is higher than 5.79% from Pt-only CE based DSSC. The new concept, easy process along with promising results provide a new approach for reducing cost but enhancing photovoltaic performances of DSSCs.

  4. Enzymatically catalytic signal tracing by a glucose oxidase and ferrocene dually functionalized nanoporous gold nanoprobe for ultrasensitive electrochemical measurement of a tumor biomarker.

    PubMed

    Cheng, Hui; Xu, Lingling; Zhang, Haili; Yu, Aimin; Lai, Guosong

    2016-07-21

    A nanoporous gold nanosphere (pAu NS) was synthesized to load high-content glucose oxidase (GOx) and ferrocene (Fc) for the successful preparation of a new gold nanoprobe. After the specific recognition of the tumor biomarker of carcinoembryonic antigen (CEA) at a gold electrode based aptasensor, this GOx and Fc dually functionalized pAu NS nanoprobe was further used for sandwich immunoreaction and signal tracing. Based on the Fc-mediated GOx-catalytic reaction, the gold nanoprobes quantitatively captured onto the electrode surface produced a sensitive electrochemical signal corresponding to the protein recognition events, which led to the development of a new biosensing method for CEA measurement. Both the high loading of GOx and Fc on the pAu NS nanocarrier and the enzymatically catalytic reaction of the nanoprobe greatly amplify the electrochemical signal; meanwhile, the immobilization of the Fc mediator on this enzyme nanoprobe and the highly specific aptamer recognition drastically decrease the background current, resulting in the achievement of ultrahigh sensitivity of the method. Under optimum conditions, this method shows an excellent analytical performance including a wide linear relationship of five-order of magnitude and a low detection limit down to 0.45 pg mL(-1). Thus this pAu NS based gold nanoprobe and the proposed immunoassay method provide great potential for practical applications. PMID:27186605

  5. pHe-induced charge-reversible NIR fluorescence nanoprobe for tumor-specific imaging.

    PubMed

    Dong, Chunhong; Liu, Zhongyun; Zhang, Lei; Guo, Weisheng; Li, Xue; Liu, Junqing; Wang, Hanjie; Chang, Jin

    2015-04-15

    Inspired by the specificity of acid tumor microenvironment, we constructed a flexible charge-reversible near-infrared (NIR) fluorescence nanoprobe in response to tumor extracellular pH (pHe) for effective tumor-specific imaging. The nanoprobe consists of an NIR-emitted CuInS2/ZnS quantum dot (CIS/ZS QDs) core and a tailored lauric acid and 2,3-dimethylmaleic anhydride modified ε-polylysine (ε-PL-g-LA/DMA) shell, which provides not only a dense protective layer for the QDs but also the ability of pHe-induced positive charge-mediated endocytosis into tumor cells. The results showed that the QDs@ε-PL-g-LA/DMA nanoprobe with a uniform size of 40 nm had high chemical stability at pH 7.4 and excellent optical properties. Especially, it swiftly reversed its surface charge to positive in 20 min when exposed to pHe due to the cleavage of the β-carboxyl amide bond of ε-PL-g-LA/DMA. Moreover, the cell uptake of the pHe-sensitive QDs nanoprobe exposed at pH 6.8 into HeLa cells is much more significant than that at pH 7.4, which further verified the availability of the electrostatic adsorptive endocytosis facilitated targeting ability. The pHe-induced targeting imparted the QDs nanoprobe a broad targeting ability in a variety of solid tumors. Furthermore, as an effective alternative mechanism for tumor targeting, responsive charge reversion is also universally applicable to other cancer theranostics agent. PMID:25799279

  6. Sonophoric nanoprobe aided pH measurement in vivo using photoacoustic spectroscopy†

    PubMed Central

    Ray, Aniruddha; Yoon, Hyung Ki; Koo Lee, Yong Eun

    2014-01-01

    Presented here is a novel method of in vivo pH sensing utilizing a hybrid optical imaging technique, photoacoustic imaging (PAI), and pH sensitive polymeric nanoprobes. Nanoprobes with hydrophobic core containing a pH sensitive dye were synthesized and used to measure the pH level ex vivo first and then in vivo by performing experiments on a rat joint model, with an achieved precision of less than 0.1 pH units. The ability of the hydrophobic functional groups in the polyacrylamide matrix to shield the molecular dye from being affected by the proteins in the plasma, and prevent the dye from leaching out, is also demonstrated. PMID:23598348

  7. Sensitivity comparison of searches for binary black hole coalescences with ground-based gravitational-wave detectors

    NASA Astrophysics Data System (ADS)

    Mohapatra, Satya; Cadonati, Laura; Caudill, Sarah; Clark, James; Hanna, Chad; Klimenko, Sergey; Pankow, Chris; Vaulin, Ruslan; Vedovato, Gabriele; Vitale, Salvatore

    2014-07-01

    Searches for gravitational-wave transients from binary black hole coalescences typically rely on one of two approaches: matched filtering with templates and morphology-independent excess power searches. Multiple algorithmic implementations in the analysis of data from the first generation of ground-based gravitational-wave interferometers have used different strategies for the suppression of non-Gaussian noise transients and have targeted different regions of the binary black hole parameter space. In this paper we compare the sensitivity of three such algorithms: matched filtering with full coalescence templates, matched filtering with ringdown templates, and a morphology-independent excess power search. The comparison is performed at a fixed false alarm rate and relies on Monte Carlo simulations of binary black hole coalescences for spinning, nonprecessing systems with a total mass of 25-350 M⊙, which covers a portion of the parameter space of stellar mass and intermediate mass black hole binaries. We find that in the mass range of 25-100 M⊙, the sensitive distance of the search, marginalized over source parameters, is the best with matched filtering to full waveform templates, which is within 10% of the next most sensitive search of morphology-independent excess power algorithm, at a false alarm rate of 3 events/year. In the mass range of 100-350 M⊙, the same comparison favors the morphology-independent excess power search within 20% of matched filtering with ringdown templates. The dependence on mass and spin is also explored.

  8. Plasmonic coupling of dual gold nanoprobes for SERS imaging of sialic acids on living cells.

    PubMed

    Song, Wanyao; Ding, Lin; Chen, Yunlong; Ju, Huangxian

    2016-08-23

    This work reports a benzoic group functionalized gold nanoflower as a bridge probe for both recognition of target sialic acids and assembly of poly(N-acetylneuraminic acid) modified gold nanoparticles, which leads to plasmonic coupling of two kinds of gold nanoprobes in a single-core-multi-satellite nanostructure to produce a sensitive surface-enhanced Raman scattering (SERS) signal for the imaging of sialic acids on living cells. PMID:27500291

  9. A multiplex and straightforward aqueous phase immunoassay protocol through the combination of SERS-fluorescence dual mode nanoprobes and magnetic nanobeads.

    PubMed

    Zong, Shenfei; Wang, Zhuyuan; Zhang, Ruohu; Wang, Chunlei; Xu, Shuhong; Cui, Yiping

    2013-03-15

    A novel aqueous phase immunoassay protocol was demonstrated, using surface enhanced Raman scattering (SERS)-fluorescence dual mode nanoprobes combined with magnetic nanobeads (MBs). Here, the dual mode nanoprobes provide an excellent multiplexing ability while the MBs greatly simplify the immunoassay process. Basically, the nanoprobes were acquired by assembling the Raman reporter tagged Au@Ag core-shell nanorods and quantum dots onto the silica nanospheres. When the specific antigens are presented in the immunoassay system containing antibody modified nanoprobes and MBs, the nanoprobes are captured by the MBs and further precipitated by a magnet. Consequently, both SERS and fluorescence signals are detected in the precipitates. Sandwich type immunoassay was conducted to examine the practicability of this protocol. Experimental results confirmed that the presented immunoassay protocol can accomplish highly specific and sensitive recognition of the target antigens. The detection limit was found out to be 0.1 pg/mL. We anticipate that high throughput bioanalysis can be fulfilled using the proposed immunoassay protocol, as the dual mode nanoprobes provide a great multiplexing capability while the MBs facilitate the convenient aqueous phase detection of the analytes. PMID:23084027

  10. Developing New Nanoprobes from Semiconductor Nanocrystals

    SciTech Connect

    Fu, Aihua

    2006-05-29

    In recent years, semiconductor nanocrystal quantum dots havegarnered the spotlight as an important new class of biological labelingtool. Withoptical properties superior to conventional organicfluorophores from many aspects, such as high photostability andmultiplexing capability, quantum dots have been applied in a variety ofadvanced imaging applications. This dissertation research goes along withlarge amount of research efforts in this field, while focusing on thedesign and development of new nanoprobes from semiconductor nanocrystalsthat are aimed for useful imaging or sensing applications not possiblewith quantum dots alone. Specifically speaking, two strategies have beenapplied. In one, we have taken advantage of the increasing capability ofmanipulating the shape of semiconductor nanocrystals by developingsemiconductor quantum rods as fluorescent biological labels. In theother, we have assembled quantum dots and gold nanocrystals into discretenanostructures using DNA. The background information and synthesis,surface manipulation, property characterization and applications of thesenew nanoprobes in a few biological experiments are detailed in thedissertation.

  11. Perfluoro anion based binary and ternary ionic liquids as electrolytes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lin, Hsi-Hsin; Peng, Jia-De; Suryanarayanan, V.; Velayutham, D.; Ho, Kuo-Chuan

    2016-04-01

    In this work, eight new ionic liquids (ILs) based on triethylammonium (TEA) or n-methylpiperidinium (NMP) cations and perfluoro carboxylate (PFC) anions having different carbon chain lengths are synthesized and their physico-chemical properties such as density, decomposition temperature, viscosity and conductivity are determined. Photovoltaic characteristics of dye-sensitized solar cells (DSSCs) with binary ionic liquids electrolytes, containing the mixture of the synthesized ILs and 1-methyl-3-propyl imidazolium iodide (PMII) (v/v = 35/65), are evaluated. Among the different ILs, solar cells containing NMP based ILs show higher VOC than that of TEA, whereas, higher JSC is noted for the DSSCs incorporated with the latter when compared to the former. Further, the photo-current of the DSSCs decreases with the increase of the carbon chain length of perfluoro carboxylate anionic group of ILs. The cell performance of the DSSC containing ternary ionic liquids-based electrolytes compose of NMP-2C/TEA-2C/PMII (v/v/v = 28/7/65) exhibits a JSC of 12.99 mA cm-2, a VOC of 639.0 mV, a FF of 0.72, and a cell efficiency of 6.01%. The extraordinary durability of the DSSC containing the above combination of electrolytes stored in dark at 50 °C is proved to be unfailing up to 1200 h.

  12. Aptamer loaded MoS2 nanoplates as nanoprobes for detection of intracellular ATP and controllable photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Jia, Li; Ding, Lin; Tian, Jiangwei; Bao, Lei; Hu, Yaoping; Ju, Huangxian; Yu, Jun-Sheng

    2015-09-01

    In this work we designed a MoS2 nanoplate-based nanoprobe for fluorescence imaging of intracellular ATP and photodynamic therapy (PDT) via ATP-mediated controllable release of 1O2. The nanoprobe was prepared by simply assembling a chlorine e6 (Ce6) labelled ATP aptamer on MoS2 nanoplates, which have favorable biocompatibility, unusual surface-area-to-mass ratio, strong affinity to single-stranded DNA, and can quench the fluorescence of Ce6. After the nanoprobe was internalized into the cells and entered ATP-abundant lysosomes, its recognition to ATP led to the release of the single-stranded aptamer from MoS2 nanoplates and thus recovered the fluorescence of Ce6 at an excitation wavelength of 633 nm, which produced a highly sensitive and selective method for imaging of intracellular ATP. Meanwhile, the ATP-mediated release led to the generation of 1O2 under 660 nm laser irradiation, which could induce tumor cell death with a lysosomal pathway. The controllable PDT provided a model approach for design of multifunctional theranostic nanoprobes. These results also promoted the development and application of MoS2 nanoplate-based platforms in biomedicine.In this work we designed a MoS2 nanoplate-based nanoprobe for fluorescence imaging of intracellular ATP and photodynamic therapy (PDT) via ATP-mediated controllable release of 1O2. The nanoprobe was prepared by simply assembling a chlorine e6 (Ce6) labelled ATP aptamer on MoS2 nanoplates, which have favorable biocompatibility, unusual surface-area-to-mass ratio, strong affinity to single-stranded DNA, and can quench the fluorescence of Ce6. After the nanoprobe was internalized into the cells and entered ATP-abundant lysosomes, its recognition to ATP led to the release of the single-stranded aptamer from MoS2 nanoplates and thus recovered the fluorescence of Ce6 at an excitation wavelength of 633 nm, which produced a highly sensitive and selective method for imaging of intracellular ATP. Meanwhile, the ATP

  13. Enzymatically catalytic deposition of gold nanoparticles by glucose oxidase-functionalized gold nanoprobe for ultrasensitive electrochemical immunoassay.

    PubMed

    Cheng, Hui; Lai, Guosong; Fu, Li; Zhang, Haili; Yu, Aimin

    2015-09-15

    A novel ultrasensitive immunoassay method was developed by combination of the enzymatically catalytic gold deposition with the prepared gold nanoprobe and the gold stripping analysis at an electrochemical chip based immunosensor. The immunosensor was constructed through covalently immobilizing capture antibody at a carbon nanotube (CNT) modified screen-printed carbon electrode. The gold nanoprobe was prepared by loading signal antibody and high-content glucose oxidase (GOD) on the nanocarrier of gold nanorod (Au NR). After sandwich immunoreaction, the GOD-Au NR nanoprobe could be quantitatively captured onto the immunosensor surface and then induce the deposition of gold nanoparticles (Au NPs) via the enzymatically catalytic reaction. Based on the electrochemical stripping analysis of the Au NR nanocarriers and the enzymatically produced Au NPs, sensitive electrochemical signal was obtained for the immunoassay. Both the GOD-induced deposition of Au NPs by the nanoprobe and the sensitive electrochemical stripping analysis on the CNTs based sensing surface greatly amplified the signal response, leading to the ultrahigh sensitivity of this method. Using carcinoembryonic antigen as a model analyte, excellent analytical performance including a wide linear range from 0.01 to 100 ng/mL and a detection limit down to 4.2 pg/mL was obtained. In addition, this immunosensor showed high specificity and satisfactory reproducibility, stability and reliability. The relatively positive detection potential excluded the conventional interference from dissolved oxygen. Thus this electrochemical chip based immunosensing method provided great potentials for practical applications. PMID:25932794

  14. Improving the sensitivity of a search for coalescing binary black holes with nonprecessing spins in gravitational wave data

    NASA Astrophysics Data System (ADS)

    Privitera, Stephen; Mohapatra, Satyanarayan R. P.; Ajith, Parameswaran; Cannon, Kipp; Fotopoulos, Nickolas; Frei, Melissa A.; Hanna, Chad; Weinstein, Alan J.; Whelan, John T.

    2014-01-01

    We demonstrate for the first time a search pipeline with improved sensitivity to gravitational waves from coalescing binary black holes with spins aligned to the orbital angular momentum by the inclusion of spin effects in the search templates. We study the pipeline recovery of simulated gravitational wave signals from aligned-spin binary black holes added to real detector noise, comparing the pipeline performance with aligned-spin filter templates to the same pipeline with nonspinning filter templates. Our results exploit a three-parameter phenomenological waveform family that models the full inspiral-merger-ringdown coalescence and treats the effect of aligned spins with a single effective spin parameter χ. We construct template banks from these waveforms by a stochastic placement method and use these banks as filters in the recently developed gstlal search pipeline. We measure the observable volume of the analysis pipeline for binary black hole signals with Mtotal and χ ∈[0,0.85]. We find an increase in observable volume of up to 45% for systems with 0.2≤χ≤0.85 with almost no loss of sensitivity to signals with 0≤χ≤0.2. We also show that the use of spinning templates in the search pipeline provides for more accurate recovery of the binary mass parameters as well as an estimate of the effective spin parameter. We demonstrate this analysis on 25.9 days of data obtained from the Hanford and Livingston detectors in LIGO's fifth observation run.

  15. Time-resolved luminescent biosensing based on inorganic lanthanide-doped nanoprobes.

    PubMed

    Zheng, Wei; Tu, Datao; Huang, Ping; Zhou, Shanyong; Chen, Zhuo; Chen, Xueyuan

    2015-03-11

    Time-resolved (TR) photoluminescence (PL) biosensing has been widely adopted in many research and medical institutions. However, commercial molecular TRPL bioprobes like lanthanide (Ln(3+))-chelates suffer from poor photochemical stability and long-term toxicity. Inorganic Ln(3+)-doped nanocrystals (NCs), owing to their superior physicochemical properties over Ln(3+)-chelates, are regarded as a new generation of luminescent nanoprobes for TRPL biosensing. The long-lived PL of Ln(3+)-doped NCs combined with the TRPL technique is able to completely suppress the interference of the short-lived background, resulting in a background-free signal and therefore a remarkable sensitivity for biosensing. In this feature article, we summarize the latest advancements in inorganic Ln(3+)-doped NCs as TRPL nano-bioprobes from their fundamental optical properties to their potential applications for ultrasensitive biodetection and high-resolution bioimaging. Future efforts towards the commercialization of these nanoprobes are also proposed. PMID:25633111

  16. Sharp gold based hybrid nanoprobes for cell imaging through dark-field microscopy

    NASA Astrophysics Data System (ADS)

    Lerouge, Frederic; Navarro, Julien R. G.; Foscan, Monica; Chaput, Frederic; Baldeck, Patrice; Parola, Stéphane

    2015-08-01

    Numerous works are based on the design, the elaboration and the study of the optical properties of gold nanoprobes for potential applications in biotechnologies (bioimaging, biosensing). Among all the possible shapes, it appears that sharp gold nanostructures exhibit interesting features due to the strong filed generated at their tips ends, making them very sensitive to the surrounding medium. Here we describe a complete study of PEGylated gold nanoparticles : nanostars and bipyramids as potential agents for bioimaging. The nanoprobes are first prepared in high yield before functionalization with a biocompatible polymer. Then, the PEGylated gold nanoparticles are incubated with melanoma B16-F10 cells and observed using Dark-field microscopy. Results show that the biocompatible gold nanoparticles are easily internalized and most of them localized within the cells.

  17. Multifunctional upconversion nanoprobe for tumor fluorescence imaging and near-infrared thermal therapy

    NASA Astrophysics Data System (ADS)

    Wei, Yanchun; Chen, Qun; Wu, Baoyan; Xing, Da

    2014-09-01

    The combination of diagnostics and therapeutics is growing rapidly in cancer treatment. Here, using upconversion nanoparticles coated with chitosan conjugated with a targeting molecule and loaded with indocyanine green (ICG), an excitation-selectable nanoprobe with highly integrated functionalities, including the emission of visible and near-infrared (NIR) light, strong optical absorption in the NIR region and high photostability was developed. After injected in mice, the nanoprobes targeted to the tumor vascular system. NIR lasers (980 and 808 nm) were then selectively applied to the mice. The results show that, the emitted upconversion fluorescence and NIR fluorescence can be used in a complementary manner for high signal/noise ratio and sensitive tumor imaging for more precise tumor localization; Highly effective photothermal therapy can be realized using 808 nm laser irradiation. The upconversion fluorescence at 654 nm is useful for monitoring treatment effect during thermal therapy. In summary, using the nanoprobes, outstanding therapeutic efficacy could be realized and the nanofabrication strategy would highlight the promise of upconversion nanoparticles in cancer theranostics.

  18. Excitation-Selectable Nanoprobe for Tumor Fluorescence Imaging and Near-Infrared Thermal Therapy.

    PubMed

    Wei, Yanchun; Chen, Qun; Wu, Baoyan; Xing, Da

    2016-01-01

    The combination of diagnostics and therapeutics is growing rapidly in cancer treatment. Here, using upconversion nanoparticles coated with chitosan conjugated with a targeting molecule and loaded with indocyanine green (ICG), we develop an excitation-selectable nanoprobe with highly integrated functionalities, including the emission of visible and near-infrared (NIR) light, strong optical absorption in the NIR region and high photostability. After intravenous injection in tumor bearing mice, the nanoprobes target to the tumor vascular system. NIR lasers (980 and 808 nm) are then selectively applied to the mice. The results show that the emitted upconversion fluorescence and NIR fluorescence can be used in a complementary manner for high signal/noise ratio and sensitive tumor imaging for more precise tumor localization. Highly effective photothermal therapy is realized using 808 nm laser irradiation, and the upconversion fluorescence at 654 nm can be used for monitoring treatment effect during the thermal therapy. In summary, using the nanoprobes, outstanding therapeutic efficacy could be realized through flexible excitation control, precise tumor localization, highly effective photothermal conversion and real-time treatment monitoring. The nanofabrication strategy highlights the promise of nanoparticles in cancer theranostics. PMID:27301175

  19. SERS nanoprobes for the monitoring of endogenous nitric oxide in living cells.

    PubMed

    Cui, Jing; Hu, Kai; Sun, Jia-Jia; Qu, Lu-Lu; Li, Da-Wei

    2016-11-15

    Nitric Oxide (NO) is a significant gaseous signalling molecule in various pathological and physiological pathways, whereas many of its functions are still ambiguous in part because of the shortage of powerful detection approaches. Herein, we present a type of reaction-based surface-enhanced Raman scattering (SERS) nanoprobes, o-phenylenediamine-modified gold nanoparticles (AuNPs/OPD), to detect the level of the endogenous NO in living cells. The detection is achieved through the SERS variation of AuNPs/OPD caused by the reaction between NO and OPD on the surface of AuNPs. The proposed SERS nanoprobes have a good stability and a rapid response to NO within 30s Moreover, as a result of the reaction specificity coupled with SERS fingerprinting, AuNPs/OPD nanoprobes demonstrate high selectivity towards NO over other biologically relevant species with a sensitivity at 10(-7)M level. Thereby, this SERS strategy can be used for monitoring NO that is endogenously produced in living macrophages, indicating immense potential in studying NO-involved pathophysiological processes in biological systems. PMID:27183283

  20. Aptamer loaded MoS2 nanoplates as nanoprobes for detection of intracellular ATP and controllable photodynamic therapy.

    PubMed

    Jia, Li; Ding, Lin; Tian, Jiangwei; Bao, Lei; Hu, Yaoping; Ju, Huangxian; Yu, Jun-Sheng

    2015-10-14

    In this work we designed a MoS2 nanoplate-based nanoprobe for fluorescence imaging of intracellular ATP and photodynamic therapy (PDT) via ATP-mediated controllable release of (1)O2. The nanoprobe was prepared by simply assembling a chlorine e6 (Ce6) labelled ATP aptamer on MoS2 nanoplates, which have favorable biocompatibility, unusual surface-area-to-mass ratio, strong affinity to single-stranded DNA, and can quench the fluorescence of Ce6. After the nanoprobe was internalized into the cells and entered ATP-abundant lysosomes, its recognition to ATP led to the release of the single-stranded aptamer from MoS2 nanoplates and thus recovered the fluorescence of Ce6 at an excitation wavelength of 633 nm, which produced a highly sensitive and selective method for imaging of intracellular ATP. Meanwhile, the ATP-mediated release led to the generation of (1)O2 under 660 nm laser irradiation, which could induce tumor cell death with a lysosomal pathway. The controllable PDT provided a model approach for design of multifunctional theranostic nanoprobes. These results also promoted the development and application of MoS2 nanoplate-based platforms in biomedicine. PMID:26367253

  1. pH-Activatable MnO-Based Fluorescence and Magnetic Resonance Bimodal Nanoprobe for Cancer Imaging.

    PubMed

    Hsu, Benedict You Wei; Ng, Michael; Tan, Aaron; Connell, John; Roberts, Thomas; Lythgoe, Mark; Zhang, Yu; Wong, Siew Yee; Bhakoo, Kishore; Seifalian, Alexander M; Li, Xu; Wang, John

    2016-03-01

    Stimuli-responsive nanoprobes that combine both fluorescence and magnetic resonance imaging (MRI) are anticipated to be highly beneficial for tumor visualization with high imaging sensitivity. By employing an interfacial templating scheme, a pH-activatable fluorescence/MRI dual-modality imaging nanoprobe is successfully developed based on the coencapsulation of MnO nanoparticles and coumarin-545T inside a hybrid silica nanoshell. To promote cancer cell targeting with high-specificity, the nanoprobes are also conjugated with folic acid to establish a greater affinity for cancer cells that over-express folate receptors on their cell membrane. In the new nanosystem, MnO nanoparticles are shown to function as an efficient fluorescence quencher of coumarin-545T prior to cellular uptake. However, fluorescence recovery is achieved upon acidic dissolution of the MnO nanoparticles following receptor-mediated endocytosis into the low pH compartments of the cancer cells. Meanwhile, the Mn(2+) ions thus released are also shown to exert a strong T1 contrast enhancement in the cancer cells. Therefore, by demonstrating the dual-activatable MRI and fluorescence imaging in response to the low pH conditions, it is envisioned that these nanoprobes would have tremendous potential for emerging cancer-imaging modalities such as image-guided cancer therapy. PMID:26895111

  2. Construction of LRET-based nanoprobe using upconversion nanoparticles with confined emitters and bared surface as luminophore.

    PubMed

    Li, Zhen; Lv, Songwei; Wang, Yali; Chen, Shiyu; Liu, Zhihong

    2015-03-11

    Upconversion nanoparticles (UCNPs) are promising energy donors for luminescence resonance energy transfer (LRET) and have widely been used to construct nanoprobes. To improve the LRET efficiency, which is currently a limiting factor for UCNPs-based bioassay, we herein propose a strategy to construct LRET-based nanoprobe using UCNPs with confined emitters and bared surface as the luminophore, with Ca(2+) as the proof-of-concept target. The sandwich-structure upconversion nanoparticles (SWUCNPs) are designed with a core-inner shell-outer shell architecture, in which the emitting ions (Ln(3+)) are precisely located in the inner shell near the particle surface, which is close enough to external energy acceptors. The target receptor (Fluo-4) is directly tagged on bared surface of SWUCNPs, which further reduces the donor-to-acceptor distance. Our strategy contributes to significantly improved LRET efficiency and hence affords an ultrahigh sensitivity for Ca(2+) detection. The as-constructed nanoprobe is structurally stable and exhibits good biocompatibility, which ensures uptake and reliable observation in living cells. The nanoprobe can be used for monitoring the different levels of cytosol [Ca(2+)] in living cells. Furthermore, it is applicable in Ca(2+) imaging in mice liver tissues. PMID:25707940

  3. A photothermally responsive nanoprobe for bioimaging based on Edman degradation.

    PubMed

    Liu, Yi; Wang, Zhantong; Zhang, Huimin; Lang, Lixin; Ma, Ying; He, Qianjun; Lu, Nan; Huang, Peng; Liu, Yijing; Song, Jibin; Liu, Zhibo; Gao, Shi; Ma, Qingjie; Kiesewetter, Dale O; Chen, Xiaoyuan

    2016-05-19

    A new type of photothermally responsive nanoprobe based on Edman degradation has been synthesized and characterized. Under irradiation by an 808 nm laser, the heat generated by the gold nanorod core breaks the thiocarbamide structure and releases the fluorescent dye Cy5.5 with increased near-infrared (NIR) fluorescence under mild acidic conditions. This RGD modified nanoprobe is capable of fluorescence imaging of ανβ3 over-expressing U87MG cells in vitro and in vivo. This Edman degradation-based nanoprobe provides a novel strategy to design activatable probes for biomedical imaging and drug/gene delivery. PMID:27149392

  4. Fluorescent magnetic hybrid nanoprobe for multimodal bioimaging

    NASA Astrophysics Data System (ADS)

    Koktysh, Dmitry; Bright, Vanessa; Pham, Wellington

    2011-07-01

    A fluorescent magnetic hybrid imaging nanoprobe (HINP) was fabricated by the conjugation of superparamagnetic Fe3O4 nanoparticles and visible light emitting (~600 nm) fluorescent CdTe/CdS quantum dots (QDs). The assembly strategy used the covalent linking of the oxidized dextran shell of magnetic particles to the glutathione ligands of QDs. The synthesized HINP formed stable water-soluble colloidal dispersions. The structure and properties of the particles were characterized by transmission electron and atomic force microscopy, energy dispersive x-ray analysis and inductively coupled plasma optical emission spectroscopy, dynamic light scattering analysis, optical absorption and photoluminescence spectroscopy, and fluorescent imaging. The luminescence imaging region of the nanoprobe was extended to the near-infrared (NIR) (~800 nm) by conjugation of the superparamagnetic nanoparticles with synthesized CdHgTe/CdS QDs. Cadmium, mercury based QDs in HINP can be easily replaced by novel water-soluble glutathione stabilized AgInS2/ZnS QDs to present a new class of cadmium-free multimodal imaging agents. The observed NIR photoluminescence of fluorescent magnetic nanocomposites supports their use for bioimaging. The developed HINP provides dual-imaging channels for simultaneous optical and magnetic resonance imaging.

  5. Identification of Paracoccidioides brasiliensis by gold nanoprobes

    NASA Astrophysics Data System (ADS)

    Martins, Jaciara F. S.; Castilho, Maiara L.; Cardoso, Maria A. G.; Carreiro, Andrea P.; Martin, Airton A.; Raniero, Leandro

    2012-01-01

    Paracoccidioides brasiliensis (P. brasiliensis) is a thermal dimorphic fungus and causal agent of paracoccidioidomycosis. Epidemiological data shows that it is mainly concentrated in Central and South America countries, with most registered cases in Colombia, Brazil, and Venezuela. The histopathological similarity with others fungal infection makes the diagnosis of P. brasiliensis more complicated. Therefore, the aim of this work was to find a positive and negative test for P. brasiliensis using gold nanoprobes as a new tool for P. brasiliensis detection. Gold nanoparticles were synthesized by reduction of gold chloride with sodium citrate. The results of this procedure is a wine-red solution with a maximum absorption in the range of ~520-530nm. A specific P. brasiliensis sequence of oligonucleotide was bonded to the nanoparticles, which maintained the wine-red color. The color changes from red to blue for negative diagnostic and is unchanged for a positive test. The H-bond interaction of DNA with the complementary DNA keeps strands together and forms double helical structure, maintaining the colloid stability. However, for non-complimentary DNA sequence the nanoprobes merge into a cluster, changing the light absorption.

  6. Fluorescent magnetic hybrid nanoprobe for multimodal bioimaging

    PubMed Central

    Bright, Vanessa

    2011-01-01

    A fluorescent magnetic hybrid imaging nanoprobe (HINP) was fabricated by conjugation of superparamagnetic Fe3O4 nanoparticles and visible light-emitting (~600 nm) fluorescent CdTe/CdS quantum dots (QDs). The assembly strategy used the covalent linking of the oxidized dextran shell of magnetic particles to the glutathione ligands of QDs. Synthesized HINP formed stable water-soluble colloidal dispersions. The structure and properties of the particles were characterized by transmission electron and atomic force microscopy, energy dispersive X-ray analysis and inductively coupled plasma optical emission spectroscopy, dynamic light scattering analysis, optical absorption and photoluminescence spectroscopy, and fluorescent imaging. The luminescence imaging region of the nanoprobe was extended to the near-infrared (NIR) (~800 nm) by conjugation of superparamagnetic nanoparticles with synthesized CdHgTe/CdS QDs. Cadmium, mercury based QDs in HINP can be easily replaced by novel water soluble glutathione stabilized AgInS2/ZnS QDs to present a new class of cadmium-free multimodal imaging agents. Observed NIR photoluminescence of fluorescent magnetic nanocomposites supports their use for bioimaging. The developed HINP provides dual-imaging channels for simultaneous optical and magnetic resonance imaging. PMID:21597146

  7. A hard X-ray nanoprobe beamline for nanoscale microscopy

    PubMed Central

    Winarski, Robert P.; Holt, Martin V.; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G. Brian; McNulty, Ian; Maser, Jörg

    2012-01-01

    The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals. PMID:23093770

  8. Dextran-based fluorescent nanoprobes for sentinel lymph node mapping.

    PubMed

    Dai, Tingting; Zhou, Shuyan; Yin, Chuyang; Li, Shengli; Cao, Weigang; Liu, Wei; Sun, Kang; Dou, Hongjing; Cao, Yilin; Zhou, Guangdong

    2014-09-01

    Biopsy of sentinel lymph node (SLN) has become a common practice to predict whether tumor metastasis has occurred, so proper SLN positioning tracers are highly required. Due to many drawbacks of SLN tracers currently used, developing ideal, biosafe SLN imaging agents is always an urgent issue. The current study designed a novel fluorescent nanoprobe for accurate SLN mapping. Dextran-based nanogel (DNG) was prepared through a highly efficient self-assembly assisted approach and serves as a multi-functional platform for conjugating wide spectra emitting fluorescent agents. The newly fabricated fluorescent DNG (FDNG) could be designed with optimum size and stable fluorescent intensity for specific SLN imaging. Furthermore, a long-term dynamic course in vivo (from 1 min to 72 h) revealed the satisfactory specificity, sensitivity, and stability for SLN mapping. Most importantly, both in vitro and in vivo evaluations indicated that FDNG had fine biosafety and biocompatibility with lymphatic endothelial cells. All these results supported that FDNG could be used as highly efficient molecular imaging probes for specific, sensitive, stable, non-invasive, and safe SLN mapping, which provides efficient and accurate location for SLN biopsy and thus predicts tumor metastasis as well as directs therapies. Besides, our recent studies further demonstrated that DNG could also serve as a specific and controllable drug carrier, indicating a potential application for specific therapies of various lymph-associated diseases. PMID:24957293

  9. A photothermally responsive nanoprobe for bioimaging based on Edman degradation

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Wang, Zhantong; Zhang, Huimin; Lang, Lixin; Ma, Ying; He, Qianjun; Lu, Nan; Huang, Peng; Liu, Yijing; Song, Jibin; Liu, Zhibo; Gao, Shi; Ma, Qingjie; Kiesewetter, Dale O.; Chen, Xiaoyuan

    2016-05-01

    A new type of photothermally responsive nanoprobe based on Edman degradation has been synthesized and characterized. Under irradiation by an 808 nm laser, the heat generated by the gold nanorod core breaks the thiocarbamide structure and releases the fluorescent dye Cy5.5 with increased near-infrared (NIR) fluorescence under mild acidic conditions. This RGD modified nanoprobe is capable of fluorescence imaging of ανβ3 over-expressing U87MG cells in vitro and in vivo. This Edman degradation-based nanoprobe provides a novel strategy to design activatable probes for biomedical imaging and drug/gene delivery.A new type of photothermally responsive nanoprobe based on Edman degradation has been synthesized and characterized. Under irradiation by an 808 nm laser, the heat generated by the gold nanorod core breaks the thiocarbamide structure and releases the fluorescent dye Cy5.5 with increased near-infrared (NIR) fluorescence under mild acidic conditions. This RGD modified nanoprobe is capable of fluorescence imaging of ανβ3 over-expressing U87MG cells in vitro and in vivo. This Edman degradation-based nanoprobe provides a novel strategy to design activatable probes for biomedical imaging and drug/gene delivery. Electronic supplementary information (ESI) available: HPLC, MS and 1H NMR spectrum. See DOI: 10.1039/c6nr01400c

  10. A General and Facile Strategy to Fabricate Multifunctional Nanoprobes for Simultaneous (19)F Magnetic Resonance Imaging, Optical/Thermal Imaging, and Photothermal Therapy.

    PubMed

    Hu, Gaofei; Li, Nannan; Tang, Juan; Xu, Suying; Wang, Leyu

    2016-09-01

    (19)F magnetic resonance imaging (MRI), due to its high sensitivity and negligible background, is anticipated to be a powerful noninvasive, sensitive, and accurate molecular imaging technique. However, the major challenge of (19)F MRI is to increase the number of (19)F atoms while maintaining the solubility and molecular mobility of the probe. Here, we successfully developed a facile and general strategy to synthesize the multifunctional (19)F MRI nanoprobes by encapsulating the hydrophobic inorganic nanoparticles (NPs) into a hybrid polymer micelle consisting of hydrolysates of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDTES) and oleylamine-functionalized poly(succinimide) (PSIOAm). Due to their good water dispersibility, excellent molecular mobility resulting from the ultrathin coating, and high (19)F atom numbers, these nanoprobes generate a separate sharp singlet of (19)F nuclear magnetic resonance (NMR) signal (at -82.8 ppm) with half peak width of ∼28 Hz, which is highly applicable for (19)F MRI. Significantly, by varying the inorganic core from metals (Au), oxides (Fe3O4), fluorides (NaYF4:Yb(3+)/Er(3+)), and phosphates (YPO4) to semiconductors (Cu7S4 and Ag2S, ZnS:Mn(2+)) NPs, which renders the nanoprobes' multifunctional properties such as photothermal ability (Au, Cu7S4), magnetism (Fe3O4), fluorescence (ZnS:Mn(2+)), near-infrared (NIR) fluorescence (Ag2S), and upconversion (UC) luminescence. Meanwhile, the as-prepared nanoprobes possess relatively small sizes (about 50 nm), which is beneficial for long-time circulation. The proof-of-concept in vitro (19)F NMR and photothermal ablation of ZnS:Mn(2+)@PDTES/PSIOAm and Cu7S4@PDTES/PSIOAm nanoprobes further suggest that these nanoprobes hold wide potentials for multifunctional applications in biomedical fields. PMID:27534896

  11. Nanoprobes, nanostructured materials and solid state materials

    NASA Astrophysics Data System (ADS)

    Yin, Houping

    2005-07-01

    Novel templates have been developed to prepare nanostructured porous materials through nonsurfactant templated pathway. And new applications of these materials, such as drug delivery and molecular imprinting, have been explored. The relationship between template content and pore structure has been investigated. The composition and pore structures were studied in detail using IR, TGA, SEM, TEM, BET and XRD. The obtained mesoporous materials have tunable diameters in the range of 2--12 nm. Due to the many advantages of this nonsurfactant templated pathway, such as environment friendly and biocompatibility, controlled release of antibiotics in the nanoporous materials were studied. The in vitro release properties were found to depend on the silica structures which were well tuned by varying the template content. A controlled long-term release pattern of vancomycin was achieved when the template content was 30 wt% or lower. Nanoscale electrochemical probes with dimensions as small as 50 nm in diameter and 1--2 mum in length were fabricated using electron beam deposition on the apex of conventional micron size electrodes. The electroactive region was limited to the extreme tip of the nanoprobe by coating with an insulating polymer and re-opening of the coating at the extreme tip. The novel nanoelectrodes thus prepared were employed to probe neurons in mouse brain slice and the results suggest that the nanoprobes were capable of recording neuronal excitatory postsynaptic potential signals. Interesting solid state chemistry was found in oxygenated iron phthalocyanine. Their Mossbauer spectra show the formation of four oxygenated species apart from the unoxygenated parent compound. The oxygen-bridged compounds formed in the solid matrix bear no resemblance to the one formed by solution chemistry. Tentative assignment of species has been made with the help of Mossbauer and IR spectroscopy. An effort to modify aniline trimer for potential nanoelectronics applications and to

  12. Nanoprobe arrays for multiple single cell insertion using heterogeneous nanosphere lithography (HNSL)

    NASA Astrophysics Data System (ADS)

    Seo, Yoon Ho; Kim, Lo Hyun; Kim, Young-Beom; Ryu, Wonhyoung

    2013-08-01

    Nanoprobe arrays for multiple single cell insertion were developed using heterogeneous nanosphere lithography. Using two heterogeneous nanoparticles as sacrificial and masking particles, high aspect ratio Si nanoprobes were fabricated in an array with spacing between the nanoprobes ranging from a few to tens of micrometers. For registered single cell analysis, multiple and precise insertion of nanoprobes into multiple single cells in a parallel fashion was demonstrated using micropipette suction and micromanipulators.

  13. A pH-sensitive binary drug delivery system based on poly(caprolactone)-heparin conjugates.

    PubMed

    Ye, Lin; Gao, Zemin; Zhou, Yu; Yin, Xuan; Zhang, Xinpeng; Zhang, Aiying; Feng, Zengguo

    2014-03-01

    PCL-heparin conjugates were synthesized by coupling mono-hydroxyl terminated PCL (Mn = 2000-10000 g/mol) with heparin via EDC/NHS chemistry. The conjugates enabled to self-assemble into the core-shell nanoparticles in around 100 nm diameter to load binary anti-cancer drugs. Lipophilic and neutral paclitaxel (PTX) was first encapsulated in the core, and then hydrophilic and positive charged doxorubicin (DOX) was incorporated into the negative charged shell of PTX loaded nanoparticles via the electrostatic interaction. The in vitro release profiles of the binary-drug loaded nanoparticles revealed that both PTX and DOX were sustainably released from the particles but behaved differently. The release of DOX was pH dependent, ensuring more drug to be released in the tumor cells than in the normal ones. Hence these particles were featured by a sequential controlled drug delivery behavior with a significant cytotoxicity to cervical cancer (Hela cell) and breast cancer (MDA-MB-321) cells. The CLSM observations clearly indicated that both loaded PTX and DOX aggregated in the nucleus of tumor cells to exert their anti-tumor pharmacodynamic effect on the cells. PMID:23554308

  14. Directed searches for continuous gravitational waves from binary systems: Parameter-space metrics and optimal Scorpius X-1 sensitivity

    NASA Astrophysics Data System (ADS)

    Leaci, Paola; Prix, Reinhard

    2015-05-01

    We derive simple analytic expressions for the (coherent and semicoherent) phase metrics of continuous-wave sources in low-eccentricity binary systems for the two regimes of long and short segments compared to the orbital period. The resulting expressions correct and extend previous results found in the literature. We present results of extensive Monte Carlo studies comparing metric mismatch predictions against the measured loss of detection statistics for binary parameter offsets. The agreement is generally found to be within ˜10 %- 30 % . For an application of the metric template expressions, we estimate the optimal achievable sensitivity of an Einstein@Home directed search for Scorpius X-1, under the assumption of sufficiently small spin wandering. We find that such a search, using data from the upcoming advanced detectors, would be able to beat the torque-balance level [R. V. Wagoner, Astrophys. J. 278, 345 (1984); L. Bildsten, Astrophys. J. 501, L89 (1998).] up to a frequency of ˜500 - 600 Hz , if orbital eccentricity is well constrained, and up to a frequency of ˜160 - 200 Hz for more conservative assumptions about the uncertainty on orbital eccentricity.

  15. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Hao, Feng; Lin, Hong; Zhang, Jing; Li, Jianbao

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency.

  16. Upconversion nanoprobes for efficiently in vitro imaging reactive oxygen species and in vivo diagnosing rheumatoid arthritis.

    PubMed

    Chen, Zhaowei; Liu, Zhen; Li, Zhenhua; Ju, Enguo; Gao, Nan; Zhou, Li; Ren, Jinsong; Qu, Xiaogang

    2015-01-01

    Over-generation of reactive oxygen species (ROS) is closely associated with the biological processes of rheumatoid arthritis (RA). Thus, efficient monitoring ROS in inflammatory joints would be essential for better understanding the pathogenesis and optimizing therapeutic interventions. Herein, we designed a ratiometric nanoprobe utilizing upconversion nanoparticles (UCNPs) conjugated with chromophore labeled hyaluronic acid (HA) for high sensitively sensing ROS in the aqueous solution, bioimaging ROS in inflammatory mimic cells and diagnosing RA in vivo. In this approach, the conjugation of HA conferred UCNPs not only water solubility but also biocompatibility and ROS recognizing properties. Particularly, the HA backbone cleavage and detachment of chromophore labeled HA fragments from UCNPs induced by ROS inhibited the luminescent energy transfer (LRET) and allowed rational metric upconversion luminescence (UCL) emission as the detection signal. Importantly, the upconversion nanoprobe showed high effectiveness for early assessing the treatment response of arthritic animals to an antiarthritic drug-methotrexate (MTX). PMID:25477167

  17. Multiplex acute leukemia cytosensing using multifunctional hybrid electrochemical nanoprobes at a hierarchically nanoarchitectured electrode interface

    NASA Astrophysics Data System (ADS)

    Zheng, Tingting; Tan, Tingting; Zhang, Qingfeng; Fu, Jia-Ju; Wu, Jia-Jun; Zhang, Kui; Zhu, Jun-Jie; Wang, Hui

    2013-10-01

    We have developed a robust, nanobiotechnology-based electrochemical cytosensing approach with high sensitivity, selectivity, and reproducibility toward the simultaneous multiplex detection and classification of both acute myeloid leukemia and acute lymphocytic leukemia cells. The construction of the electrochemical cytosensor involves the hierarchical assembly of dual aptamer-functionalized, multilayered graphene-Au nanoparticle electrode interface and the utilization of hybrid electrochemical nanoprobes co-functionalized with redox tags, horseradish peroxidase, and cell-targeting nucleic acid aptamers. The hybrid nanoprobes are multifunctional, capable of specifically targeting the cells of interest, amplifying the electrochemical signals, and generating distinguishable signals for multiplex cytosensing. The as-assembled electrode interface not only greatly facilitates the interfacial electron transfer process due to its high conductivity and surface area but also exhibits excellent biocompatibility and specificity for cell recognition and adhesion. A superstructured sandwich-type sensor geometry is adopted for electrochemical cytosensing, with the cells of interest sandwiched between the nanoprobes and the electrode interface. Such an electrochemical sensing strategy allows for ultrasensitive, multiplex acute leukemia cytosensing with a detection limit as low as ~350 cells per mL and a wide linear response range from 5 × 102 to 1 × 107 cells per mL for HL-60 and CEM cells, with minimal cross-reactivity and interference from non-targeting cells. This electrochemical cytosensing approach holds great promise as a new point-of-care diagnostic tool for early detection and classification of human acute leukemia and may be readily expanded to multiplex cytosensing of other cancer cells.We have developed a robust, nanobiotechnology-based electrochemical cytosensing approach with high sensitivity, selectivity, and reproducibility toward the simultaneous multiplex

  18. Photoacoustics and fluorescence based nanoprobes towards functional and structural imaging in vivo

    NASA Astrophysics Data System (ADS)

    Ray, Aniruddha

    Imaging of chemical analytes and structural properties related to physiological activities within biological systems is of great bio-medical interest; it can contribute to the fundamental understanding of biological systems and can be applied to the diagnosis and prognosis of diseases, especially tumors. The work presented in this thesis focuses on the development and application of polymeric nanoprobe aided optical imaging of chemical analytes (Oxygen, pH) and structural properties in live cells and animal models. To this end, specific nanoprobes, based on the polyacrylamide nanoplatform, bearing both appropriate targeting functionalities, and high concentrations of sensing and contrast agents, have been developed. The nanoprobes presented here are biodegradable, biocompatible and non-toxic, rendering them safe for in vivo use. Furthermore the nanoprobes are designed to have variable optical properties that are dependent on the local concentration of the specific analyte of interest. Optical imaging techniques that are particularly suited for deep tissue applications, such as two-photon fluorescence and photoacoustics, were applied for non-invasive real-time imaging and sensing in cancer cells, tumor spheroids and animal models. Our results demonstrate that this technique enables high sensitive detection of chemical analytes with a sensitivity of <5 Torr for oxygen and <0.1 pH units in vivo, which is better than the currently available in vivo functional imaging techniques. This non-invasive and non-ionizing, yet low cost, method will enable morphological and functional evaluation across any tissue, with both high spatial and temporal resolution but without eliciting short- or long-term tissue damage. Currently no gold standard exists for such xii functional imaging. The approach presented here can be used for early detection and diagnosis of tumors, as well as for monitoring the progression of disease and therapy. This technique will also enable observing

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

    PubMed

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

    2014-05-01

    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. PMID:24631541

  20. Nanofiber-net-binary structured membranes for highly sensitive detection of trace HCl gas.

    PubMed

    Wang, Xianfeng; Wang, Jialin; Si, Yang; Ding, Bin; Yu, Jianyong; Sun, Gang; Luo, Wenjing; Zheng, Gang

    2012-12-01

    This work describes the detection of trace hydrogen chloride (HCl) gas through analyses of the resonance frequency signal from quartz crystal microbalance (QCM) sensors coated with polyaniline (PANI) functionalized polyamide 6 (PA 6) (PANI-PA 6) nanofiber-net-binary (NNB) structured membranes. The PA 6 NNB substrate comprising nanofibers and spider-web-like nano-nets fabricated by a versatile electro-spinning/netting (ESN) process offered an ideal interface for the uniform PANI functionalization and enhanced sensing performance. Benefiting from the large specific surface area, high porosity, and strong adhesive force to the QCM electrode of the PANI-PA 6 NNB membranes, the developed HCl-selective sensors exhibited a rapid response, good reproducibility and stability, and low detection limit (7 ppb) at room temperature. Additionally, the PANI-PA 6 NNB sensing membranes presented visible color changes upon cycled exposure to HCl and ammonia, suggesting their potential application in the development of colorimetric sensors. The PANI-PA 6 NNB coated QCM sensors are considered to be a promising candidate for trace HCl gas detection in practical applications. PMID:23108331

  1. Silica-based nanoprobes for biomedical imaging and theranostic applications†

    PubMed Central

    Vivero-Escoto, Juan L.; Huxford-Phillips, Rachel C.

    2013-01-01

    Nanoparticle-based contrast agents are attracting a great deal of attention for various biomedical imaging and theranostic applications. Compared to conventional contrast agents, nanoparticles possess several potential advantages to improve in vivo detection and to enhance targeting efficiency. Silica-based nanoprobes can be engineered to achieve longer blood circulation times, specific clearance pathways, and multivalent binding. In this tutorial review, we summarize the latest progress on designing silica-based nanoprobes for imaging and theranostic applications. The synthesis of both solid silica and mesoporous silica nanoparticles is described, along with different approaches used for surface functionalization. Special emphasis is placed on the application of silica-based nanoprobes in optical, magnetic resonance, and multimodal imaging. The latest breakthroughs in the applications of silica nanoparticles as theranostic agents are also highlighted. PMID:22234515

  2. Aptamer-modified magnetic nanoprobe for molecular MR imaging of VEGFR2 on angiogenic vasculature

    NASA Astrophysics Data System (ADS)

    Kim, Bongjune; Yang, Jaemoon; Hwang, Myeonghwan; Choi, Jihye; Kim, Hyun-Ouk; Jang, Eunji; Lee, Jung Hwan; Ryu, Sung-Ho; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2013-09-01

    Nucleic acid-based aptamers have been developed for the specific delivery of diagnostic nanoprobes. Here, we introduce a new class of smart imaging nanoprobe, which is based on hybridization of a magnetic nanocrystal with a specific aptamer for specific detection of the angiogenic vasculature of glioblastoma via magnetic resonance (MR) imaging. The magnetic nanocrystal imaging core was synthesized using the thermal decomposition method and enveloped by carboxyl polysorbate 80 for water solubilization and conjugation of the targeting moiety. Subsequently, the surface of the carboxylated magnetic nanocrystal was modified with amine-functionalized aptamers that specifically bind to the vascular growth factor receptor 2 (VEGFR2) that is overexpressed on angiogenic vessels. To assess the targeted imaging potential of the aptamer-conjugated magnetic nanocrystal for VEGFR2 markers, the magnetic properties and MR imaging sensitivity were investigated using the orthotopic glioblastoma mouse model. In in vivo tests, the aptamer-conjugated magnetic nanocrystal effectively targeted VEGFR2 and demonstrated excellent MR imaging sensitivity with no cytotoxicity.

  3. An Ultrasensitive Chemiluminescence Biosensor for Carcinoembryonic Antigen Based on Autocatalytic Enlargement of Immunogold Nanoprobes

    PubMed Central

    Hao, Minjia; Ma, Zhanfang

    2012-01-01

    A sensitive flow injection chemiluminescence assay for carcinoembryonic antigen (CEA) detection based on signal amplification with gold nanoparticles (NPs) is reported in the present work. The sandwich system of CEA/anti-CEA/goat-anti-mouse IgG functionalized Au nanoparticles was used as the sensing platform. In order to improve detection sensitivity, a further gold enlargement step was developed based on the autocatalytic Au deposition of gold nanoprobes via the reduction of AuCl4− to Au0 on their surface in the presence of NH2OH·HCl. AuCl4−, which is a soluble product of gold nanoprobes, served as an analyte in the CL reaction for the indirect measurement of CEA. Under optimized conditions, the CL intensity of the system was linearly related to the logarithm of CEA concentration in the range of 100 pg·mL−1 to 1,000 ng·mL−1, with a detection limit of 20 pg·mL−1. PMID:23443399

  4. MoS2-based nanoprobes for detection of silver ions in aqueous solutions and bacteria.

    PubMed

    Yang, Yu; Liu, Teng; Cheng, Liang; Song, Guosheng; Liu, Zhuang; Chen, Meiwan

    2015-04-15

    Silver as an extensively used antibacterial agent also poses potential threats to the environment and human health. Hence, in this work, we design a fluorescent nanoprobe by using rhodamine B isothiocyanate (RhoBS) adsorbed MoS2 nanosheets to realize sensitive and selective detection of Ag(+). On the surface of RhoBS-loaded MoS2 nanosheets, Ag(+) can be reduced to Ag nanoparticles, which afterward could not only lead to the detachment of RhoBS molecules and thus their recovered fluorescence but also the surface-enhanced fluorescence from RhoBS remaining adsorbed on MoS2. Such an interesting mechanism allows highly sensitive detection of Ag(+) (down to 10 nM) with great selectivity among other metal ions. Moreover, we further demonstrate that our MoS2-RhoBS complex could act as a nontoxic nanoprobe to detect Ag(+) in live bacteria samples. Our work resulted from an unexpected finding and suggests the promise of two-dimensional transition-metal sulfide nanosheets as a novel platform for chemical and biological sensing. PMID:25776005

  5. Bacteriophage-based nanoprobes for rapid bacteria separation

    NASA Astrophysics Data System (ADS)

    Chen, Juhong; Duncan, Bradley; Wang, Ziyuan; Wang, Li-Sheng; Rotello, Vincent M.; Nugen, Sam R.

    2015-10-01

    The lack of practical methods for bacterial separation remains a hindrance for the low-cost and successful development of rapid detection methods from complex samples. Antibody-tagged magnetic particles are commonly used to pull analytes from a liquid sample. While this method is well-established, improvements in capture efficiencies would result in an increase of the overall detection assay performance. Bacteriophages represent a low-cost and more consistent biorecognition element as compared to antibodies. We have developed nanoscale bacteriophage-tagged magnetic probes, where T7 bacteriophages were bound to magnetic nanoparticles. The nanoprobe allowed the specific recognition and attachment to E. coli cells. The phage magnetic nanprobes were directly compared to antibody-conjugated magnetic nanoprobes. The capture efficiencies of bacteriophages and antibodies on nanoparticles for the separation of E. coli K12 at varying concentrations were determined. The results indicated a similar bacteria capture efficiency between the two nanoprobes.The lack of practical methods for bacterial separation remains a hindrance for the low-cost and successful development of rapid detection methods from complex samples. Antibody-tagged magnetic particles are commonly used to pull analytes from a liquid sample. While this method is well-established, improvements in capture efficiencies would result in an increase of the overall detection assay performance. Bacteriophages represent a low-cost and more consistent biorecognition element as compared to antibodies. We have developed nanoscale bacteriophage-tagged magnetic probes, where T7 bacteriophages were bound to magnetic nanoparticles. The nanoprobe allowed the specific recognition and attachment to E. coli cells. The phage magnetic nanprobes were directly compared to antibody-conjugated magnetic nanoprobes. The capture efficiencies of bacteriophages and antibodies on nanoparticles for the separation of E. coli K12 at varying

  6. Highly stable SERS pH nanoprobes produced by co-solvent controlled AuNP aggregation.

    PubMed

    Wei, Haoran; Willner, Marjorie R; Marr, Linsey C; Vikesland, Peter J

    2016-08-15

    Production of gold nanoparticle (AuNP) surface-enhanced Raman spectroscopy (SERS) nanoprobes requires replicable aggregation to produce multimers with high signal intensity. Herein, we illustrate a novel, yet simple, approach to produce SERS nanoprobes through control of co-solvent composition. AuNP multimers were produced by mixing AuNP monomers in water : ethanol co-solvent for variable periods of time. By varying the water : ethanol ratio and the amount of 4-mercaptobenzoic acid (4-MBA) present, the aggregation rate can be systematically controlled. Thiolated poly(ethylene glycol) was then added to halt the aggregation process and provide steric stability. This approach was used to produce pH nanoprobes with excellent colloidal stability in high ionic strength environments and in complex samples. The pH probe exhibits broad pH sensitivity over the range 6-11 and we calculate that a single AuNP dimer in a 35 fL volume is sufficient to generate a detectable SERS signal. As a proof-of-concept, the probes were used to detect the intracellular pH of human prostate cancer cells (PC-3). The internalized probes exhibit a strong 4-MBA signal without any interfering bands from either the cells or the culture media and produce exceptionally detailed pH maps. pH maps obtained from 19 xy surface scans and 14 yz depth scans exhibit highly consistent intracellular pH in the range of 5 to 7, thus indicating the greater reliability and reproducibility of our pH probes compared with other probes previously reported in the literature. Our water : ethanol co-solvent production process is fast, simple, and efficient. Adjustment of solvent composition may become a powerful way to produce SERS tags or nanoprobes in the future. PMID:27143623

  7. In vivo tumor-targeted dual-modal fluorescence/CT imaging using a nanoprobe co-loaded with an aggregation-induced emission dye and gold nanoparticles.

    PubMed

    Zhang, Jimei; Li, Chan; Zhang, Xu; Huo, Shuaidong; Jin, Shubin; An, Fei-Fei; Wang, Xiaodan; Xue, Xiangdong; Okeke, C I; Duan, Guiyun; Guo, Fengguang; Zhang, Xiaohong; Hao, Jifu; Wang, Paul C; Zhang, Jinchao; Liang, Xing-Jie

    2015-02-01

    As an intensely studied computed tomography (CT) contrast agent, gold nanoparticle has been suggested to be combined with fluorescence imaging modality to offset the low sensitivity of CT. However, the strong quenching of gold nanoparticle on fluorescent dyes requires complicated design and shielding to overcome. Herein, we report a unique nanoprobe (M-NPAPF-Au) co-loading an aggregation-induced emission (AIE) red dye and gold nanoparticles into DSPE-PEG(2000) micelles for dual-modal fluorescence/CT imaging. The nanoprobe was prepared based on a facile method of "one-pot ultrasonic emulsification". Surprisingly, in the micelles system, fluorescence dye (NPAPF) efficiently overcame the strong fluorescence quenching of shielding-free gold nanoparticles and retained the crucial AIE feature. In vivo studies demonstrated the nanoprobe had superior tumor-targeting ability, excellent fluorescence and CT imaging effects. The totality of present studies clearly indicates the significant potential application of M-NPAPF-Au as a dual-modal non-invasive fluorescence/X-ray CT nanoprobe for in vivo tumor-targeted imaging and diagnosis. PMID:25542798

  8. The sensitivity of Daphnia magna and Daphnia curvirostris to 10 veterinary antibacterials and to some of their binary mixtures.

    PubMed

    Dalla Bona, Mirco; Di Leva, Vincenzo; De Liguoro, Marco

    2014-11-01

    Aim of this study was to evaluate the suitability of Daphnia curvirostris for the acute toxicity test usually performed on Daphnia magna, and to compare the sensitivity of the two species toward 10 antibacterials [enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimethoxine (SDM) and trimethoprim (TMP)] and some of their binary mixtures. Furthermore, a tentative prolonged-toxicity test (lasting 13d) was settled up in order to evidence toxic responses with drug concentrations that were uneffective in the classic 48h immobilization test. Results showed that D. curvirostris was more sensitive than D. magna to the majority of compounds (6 out of 10). Lowest 48h EC50s were obtained with EFX (4.3mgL(-1) in D. curvirostris) and SGD (6.2mgL(-1) in D. magna). The toxicity of paired compounds was always concentration-additive or less than concentration-additive. In the prolonged-toxicity test mortality and/or reproduction inhibition were constantly observed. It was concluded that: (1) D. curvirostris could be a suitable model for the evaluation of acute toxicity of antibacterials since its sensitivity was generally greater than that of D. magna; (2) the toxicity of EFX and SGD should be given special attention as the two compounds, in the prolonged test, showed to be active at concentrations of 0.9mgL(-1) and 2.5mgL(-1), respectively; (3) the concentration addition is usually a reasonable worst case estimation of the environmental impact of antibacterial mixtures. PMID:24630458

  9. Multifunctional Nanoprobes for Cancer Cell Targeting, Imaging and Anticancer Drug Delivery

    NASA Astrophysics Data System (ADS)

    Linkov, Pavel; Laronze-Cochard, Marie; Sapi, Janos; Sidorov, Lev N.; Nabiev, Igor

    The diagnosis and treatment of cancer have been greatly improved with recent developments in bio-nanotechnology, including engineering of multifunctional probes. One of the promising nanoscale tools for cancer imaging is fluorescent quantum dots (QDs), whose small size and unique optical properties allow them to penetrate into cells and ensure highly sensitive optical diagnosis of cancer at the cellular level. Furthermore, novel multi-functional probes have been developed in which QDs are conjugated with one or several functional molecules, including targeting moieties and therapeutic agents. Here, the strategy for engineering novel nanocarriers for controlled nucleus-targeted antitumor drug delivery and real-time imaging by single- or two-photon microscopy is described. A triple multifunctional nanoprobe is being developed that consists of a nitrogen-based heterocyclic derivative, an anticancer agent interacting with a DNA in living cells; a recognized molecule serving as a vector responsible for targeted delivery of the probe into cancer cells; and photoluminescent QDs providing the imaging capability of the probe. Subsequent optimization of the multifunctional nanoprobe will offer new possibilities for cancer diagnosis and treatment.

  10. A turn-on fluorescent nanoprobe for selective determination of selenium(IV).

    PubMed

    Liang, Song; Chen, Jiao; Pierce, David T; Zhao, Julia Xiaojun

    2013-06-12

    A turn-on fluorescent nanoprobe was developed for selective determination of selenium(IV). A trace amount of selenium, as an essential nutrient, plays an important role in human health. It has been proven that a selenium deficiency will result in serious health problems. The developed nanoprobe is capable of in situ detection of selenium with target-induced signaling, and no separation step is needed. The nanoprobe consists of a silica nanoparticle core and a coating layer containing selenium(IV)-induced fluorescent molecules, 3,3'-diaminobenzidine (DAB). The nanoprobes have no fluorescence signals if they are not exposed to selenium(IV). However, the nanoprobes will be "turned on", with fluorescence, when they bind to the targets of selenium(IV). With this strategy, the selenium(IV) are first collected and enriched on a small domain of the nanoprobes. Then, with an excitation at 420 nm, the nanoprobes emit fluorescence signals at 530 nm. The fluorescence intensity is proportional to the selenium concentration. A fluorescence microscope was used to monitor the process of enriching and collecting of the selenium(IV) by the nanoprobes. The optimal conditions for the determination of selenium(IV) using the nanoprobe were investigated including pH, solvent, and linear range. The interference from common metal ions was studied as well. This study is expected to shed light on how to design turn-on fluorescent nanoprobes for in situ monitoring of a wide variety of targets in biological processes. PMID:23676764

  11. Design and assembly of supramolecular dual-modality nanoprobes

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Zhang, Pengcheng; Ray Banerjee, Sangeeta; Xu, Jiadi; Pomper, Martin G.; Cui, Honggang

    2015-05-01

    We report the design and synthesis of self-assembling dual-modality molecular probes containing both a fluorophore for optical imaging and a metal ion chelator for imaging with MRI or radionuclide methods. These molecular probes can spontaneously associate into spherical nanoparticles under physiological conditions. We demonstrate the use of these supramolecular nanoprobes for live-cell optical imaging, as well as their potential use as MRI contrast agents after complexation with gadolinium. Our results suggest that self-assembly into supramolecular nanoprobes presents an effective means to enhance and tune the relaxivities of molecular probes.We report the design and synthesis of self-assembling dual-modality molecular probes containing both a fluorophore for optical imaging and a metal ion chelator for imaging with MRI or radionuclide methods. These molecular probes can spontaneously associate into spherical nanoparticles under physiological conditions. We demonstrate the use of these supramolecular nanoprobes for live-cell optical imaging, as well as their potential use as MRI contrast agents after complexation with gadolinium. Our results suggest that self-assembly into supramolecular nanoprobes presents an effective means to enhance and tune the relaxivities of molecular probes. Electronic supplementary information (ESI) available: Experimental methods, materials, synthesis schemes, sample characterization, fluorescence measurements, cellular uptake and MRI experimental details. See DOI: 10.1039/c5nr01518a

  12. An ultrasmall and metabolizable PEGylated NaGdF4:Dy nanoprobe for high-performance T1/T2-weighted MR and CT multimodal imaging

    NASA Astrophysics Data System (ADS)

    Jin, Xiaoying; Fang, Fang; Liu, Jianhua; Jiang, Chunhuan; Han, Xueli; Song, Zhongkai; Chen, Jinxing; Sun, Guoying; Lei, Hao; Lu, Lehui

    2015-09-01

    Lanthanide-based multimodal probes with high sensitivity, simple synthesis strategy, and good biocompatibility promise new applications for clinical diagnosis. However, today's challenge is not only to develop high-performance multimodal probes for more accurate and reliable diagnosis, but also to understand the fate of these probes in vivo. In this context, a novel PEGylated Dy-doped NaGdF4 nanoprobe (PEG-NaGdF4:Dy) was designed and fabricated as a T1/T2-weighted MRI/CT imaging agent. This nanoprobe has a distinct longitudinal relaxivity (r1 = 5.17 mM-1 s-1), relatively high transverse relaxivity (r2 = 10.64 mM-1 s-1), and exhibits strong X-ray attenuation properties (44.70 HU L g-1) in vitro. Furthermore, T1/T2-weighted MRI/CT imaging in vivo confirmed that this PEG-NaGdF4:Dy nanoprobe could lead to a significant contrast enhancement effect on liver, spleen and kidney at 24 h post injection. The MTT assay, histological analysis, and biodistribution investigation demonstrated that this multifunctional nanoprobe possessed relatively low cytotoxicity, negligible tissue damage and could be completely excreted out of the body of mice as time prolonged. Therefore, the present PEG-NaGdF4:Dy nanoprobe has the potential for the development of multifunctional T1/T2-weighted MRI/CT imaging to provide more comprehensive and accurate diagnosis information.Lanthanide-based multimodal probes with high sensitivity, simple synthesis strategy, and good biocompatibility promise new applications for clinical diagnosis. However, today's challenge is not only to develop high-performance multimodal probes for more accurate and reliable diagnosis, but also to understand the fate of these probes in vivo. In this context, a novel PEGylated Dy-doped NaGdF4 nanoprobe (PEG-NaGdF4:Dy) was designed and fabricated as a T1/T2-weighted MRI/CT imaging agent. This nanoprobe has a distinct longitudinal relaxivity (r1 = 5.17 mM-1 s-1), relatively high transverse relaxivity (r2 = 10.64 mM-1 s-1), and

  13. Mirror Metrology Using Nano-Probe Supports

    NASA Technical Reports Server (NTRS)

    Robinson, David; Hong, Maoling; Byron, Glenn; McClelland, Ryan; Chan, Kai-Wing

    2012-01-01

    stabilize the mirror for measurement, nano-probes support the mirror, causing the mirror to be over-constrained.

  14. 3D Image Processing of Two-Photon Microscopy Images Depicting Nanoprobes in Skin

    NASA Astrophysics Data System (ADS)

    Bongo, Andrew E.

    Choosing a deconvolution algorithm can be beneficial when imaging nanoprobes in skin by means of two-photon microscopy. By design, deconvolution algorithms can increase the signal to noise ratio of the raw images and thus make it easier to identify discrete, subresolution nanoprobes from blurry two-photon image data. This poses the favorable benefit of knowing more precise locations of nanoprobes inside skin. This thesis demonstrates how the Expectation-Maximization deconvolution algorithm (EM algorithm) can be applied to three-dimensional, two-photon images depicting quantum dot nanoprobes inside human skin. This was accomplished in part by devising a way to deliver nanoprobes inside skin by means of low frequency ultrasound. Many nanoprobes become sparsely scattered inside skin when using this nanoprobe delivery methodology. The scattered nanoprobes resulting from the nanoprobe delivery pose a unique benefit in acquiring an experimental point spread function of the imaging system. This in turn gives an accurate representation of the point spread function that can be used as an input to the EM algorithm. The methodology of utilizing the EM algorithm in this manner is presented.

  15. Horseradish peroxidase and aptamer dual-functionalized nanoprobe for the amplification detection of alpha-methylacyl-CoA racemase.

    PubMed

    Zeng, Yongyi; Zheng, Aixian; Wu, Jing; Cai, Zhixiong; Huang, Aimin; Liu, Xiaolong

    2015-10-29

    Alpha-methylacyl-CoA racemase (AMACR) is over-expressed in many cancer types and can serve as a novel diagnostic biomarker. Development of convenient and sensitive detection methods of AMACR is of particular importance for cancer diagnosis. Aptamers are a type of recognition elements, which possess many advantages over antibody, making them suitable for applications in biosensing and biotechnology. In this work, we use the efficient surface modification of gold nanoparticles (AuNPs) to prepare the horseradish peroxidase (HRP) and aptamer dual-functionalized nanoprobe. The immobilization of HRP and thiol-terminated aptamer on the surface of AuNPs can be achieved through electrostatic interaction and the formation of Au-S bond, respectively. This nanoprobe, which is used as discriminating and catalytic probe, can be combined with enzyme immunoassay method to increase the detection sensitivity of AMACR. The detection limit can reach as low as 4.6 pg mL(-1) due to the dual signal amplification from enzymatic cycling and the high loading of enzymes on AuNPs. This sensitivity is about three orders of magnitude higher than that of AMACR aptamer based fluorescence method, which is also comparable to or one order of magnitude higher than that of ELISA. Furthermore, this method is more simple and effective, which not only avoids the conjugation between recognition element and the catalytic enzyme, but also achieves greater signal amplification. This assay could be used as a sensitive and selective platform for the detection of target protein. PMID:26547498

  16. Achieving Vibration Stability of the NSLS-II Hard X-ray Nanoprobe Beamline

    SciTech Connect

    Simos, N.; Chu, Y. N.; Broadbent, A.; Nazaretski, E.; Margulies, L.; Dyling, O.; Shen, Q.; Fallier, M.

    2010-08-30

    The Hard X-ray Nanoprobe (HXN) Beamline of National Synchrotron Light Source II (NSLS-lI) requires high levels of stability in order to achieve the desired instrument resolution. To ensure that the design of the endstation helps meet the stringent criteria and that natural and cultural vibration is mitigated both passively and actively, a comprehensive study complimentary to the design process has been undertaken. Vibration sources that have the potential to disrupt sensitive experiments such as wind, traffic and NSLS II operating systems have been studied using state of the art simulations and an array of field data. Further, final stage vibration isolation principles have been explored in order to be utilized in supporting endstation instruments. This paper presents results of the various study aspects and their influence on the HXN design optimization.

  17. Andreev nanoprobe of half-metallic CrO2 films using superconducting cuprate tips

    NASA Astrophysics Data System (ADS)

    Turel, C. S.; Guilaran, I. J.; Xiong, P.; Wei, J. Y. T.

    2011-11-01

    Superconducting tips of YBa2Cu3O7-x were used to perform point-contact Andreev reflection spectroscopy on half-metallic CrO2 thin films. At 4.2 K, strong suppression of the d-wave Andreev reflection characteristics was observed, consistent with the high spin polarization of CrO2. Our technique was validated by comparison with data taken on non-magnetic Au films and with data taken by superconducting Pb tips. The point contacts were estimated to be ≲10 nm in size, attesting to their ballistic and microscopic nature. Our results demonstrate the feasibility of using superconducting cuprate tips as spin-sensitive nanoprobes of ferromagnets.

  18. Electrochemical nanoprobes for the chemical detection of neurotransmitters

    PubMed Central

    Colombo, Michelle L.

    2015-01-01

    Neurotransmitters, acting as chemical messengers, play an important role in neurotransmission, which governs many functional aspects of nervous system activity. Electrochemical probes have proven a very useful technique to study neurotransmission, especially to quantify and qualify neurotransmitters. With the emerging interests in probing neurotransmission at the level of single cells, single vesicles, as well as single synapses, probes that enable detection of neurotransmitters at the nanometer scale become vitally important. Electrochemical nanoprobes have been successfully employed in nanometer spatial resolution imaging of single nanopores of Si membrane and single Au nanoparticles, providing both topographical and chemical information, thus holding great promise for nanometer spatial study of neurotransmission. Here we present the current state of electrochemical nanoprobes for chemical detection of neurotransmitters, focusing on two types of nanoelectrodes, i.e. carbon nanoelectrode and nano-ITIES pipet electrode. PMID:26327927

  19. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes.

    PubMed

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  20. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes

    PubMed Central

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J.; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C.; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  1. MRI nanoprobes based on chemical exchange saturation transfer: LnIII chelates anchored on the surface of mesoporous silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Ferrauto, Giuseppe; Carniato, Fabio; Tei, Lorenzo; Hu, He; Aime, Silvio; Botta, Mauro

    2014-07-01

    The formation of ternary complexes between neutral LnIII-DO3A chelates anchored on MCM-41 mesoporous silica nanoparticles (MSNs) and silanol groups on the surface allows obtaining highly efficient chemical exchange saturation transfer (CEST) MRI nanoprobes. These new probes achieve excellent sensitivity in the μM range (per LnIII ion), significantly greater than that of other paramagnetic CEST nanosystems such as dendrimers or micelles and three orders of magnitude higher than that of the corresponding molecular agents.The formation of ternary complexes between neutral LnIII-DO3A chelates anchored on MCM-41 mesoporous silica nanoparticles (MSNs) and silanol groups on the surface allows obtaining highly efficient chemical exchange saturation transfer (CEST) MRI nanoprobes. These new probes achieve excellent sensitivity in the μM range (per LnIII ion), significantly greater than that of other paramagnetic CEST nanosystems such as dendrimers or micelles and three orders of magnitude higher than that of the corresponding molecular agents. Electronic supplementary information (ESI) available: Synthesis and characterization of the materials; Z- and ST-spectra of all materials; sensitivity threshold for TmDO3A-MCM-41 and EuDO3A-MCM-41 pH and temperature dependence of ST% for TbDO3A-MCM-41. See DOI: 10.1039/c4nr02753a

  2. Parameter estimation using a complete signal and inspiral templates for low-mass binary black holes with Advanced LIGO sensitivity

    NASA Astrophysics Data System (ADS)

    Cho, Hee-Suk

    2015-12-01

    We study the validity of inspiral templates in gravitational wave data analysis with Advanced LIGO sensitivity for low mass binary black holes with total masses of M≤slant 30{M}⊙ . We mainly focus on the nonspinning system. As our complete inspiral-merger-ringdown waveform model ({I}{M}{R} ), we assume the phenomenological model, ‘PhenomA’, and define our inspiral template model ({{I}}{{merg}}) by taking the inspiral part into account from {I}{M}{R} up to the merger frequency ({f}{{merg}}). We first calculate the true statistical uncertainties using {I}{M}{R} signals and {I}{M}{R} templates. Next, using {I}{M}{R} signals and {{I}}{{merg}} templates, we calculate fitting factors and systematic biases, and compare the biases with the true statistical uncertainties. We find that the valid criteria of the bank of {{I}}{{merg}} templates are obtained as {M}{{crit}}˜ 24{M}⊙ for detection (if M\\gt {M}{{crit}}, the fitting factor is smaller than 0.97), and {M}{{crit}}˜ 26{M}⊙ for parameter estimation (if M\\gt {M}{{crit}}, the systematic bias is larger than the true statistical uncertainty where the signal-to-noise ratio is 20), respectively. In order to see the dependence on the cutoff frequency of the inspiral waveforms, we define another inspiral model {{I}}{{isco}} which is terminated at the innermost-stable-circular-orbit frequency ({f}{{isco}}\\lt {f}{{merg}}). We find that the valid criteria of the bank of {{I}}{{isco}} templates are obtained as {M}{{crit}}˜ 15{M}⊙ and ˜ 17{M}⊙ for detection and parameter estimation, respectively. We investigate the statistical uncertainties for the inspiral template models considering various signal-to-noise ratios, and compare those to the true statistical uncertainties. We also consider the aligned-spinning system with fixed mass ratio ({m}1/{m}2=3) and spin (χ =0.5) by employing the recent phenomenological model, ‘PhenomC’. In this case, we find that the true statistical uncertainties can be much larger

  3. Fabrication of SERS-fluorescence dual modal nanoprobes and application to multiplex cancer cell imaging

    NASA Astrophysics Data System (ADS)

    Lee, Sangyeop; Chon, Hyangah; Yoon, Soo-Young; Lee, Eun Kyu; Chang, Soo-Ik; Lim, Dong Woo; Choo, Jaebum

    2011-12-01

    We report a highly sensitive optical imaging technology using surface-enhanced Raman scattering (SERS)-fluorescence dual modal nanoprobes (DMNPs). Fluorescence microscopy is a well-known imaging technique that shows specific protein distributions within cells. However, most currently available fluorescent organic dyes have relatively weak emission intensities and are rapidly photo-bleached. Thus more sensitive and stable probes are needed. In this work we develop DMNPs, which can be used for both SERS and fluorescence detection. SERS detection is a powerful technique that allows ultrasensitive chemical or biochemical analysis through unlimited multiplexing and single molecule sensitivity. Combining advantages of fluorescence and SERS allows these dual modal nanostructures to be used as powerful probes for novel biomedical imaging. In this work, the fabrication and characterization of the SERS-fluorescence DMNPs and application to biological imaging were investigated using markers CD24 and CD44, which are co-expressed in MDA-MB-231 breast cancer cells, as a model system. SERS imaging with DMNPs was found to be a powerful tool to determine the co-localization of CD24 and CD44 in the cell.We report a highly sensitive optical imaging technology using surface-enhanced Raman scattering (SERS)-fluorescence dual modal nanoprobes (DMNPs). Fluorescence microscopy is a well-known imaging technique that shows specific protein distributions within cells. However, most currently available fluorescent organic dyes have relatively weak emission intensities and are rapidly photo-bleached. Thus more sensitive and stable probes are needed. In this work we develop DMNPs, which can be used for both SERS and fluorescence detection. SERS detection is a powerful technique that allows ultrasensitive chemical or biochemical analysis through unlimited multiplexing and single molecule sensitivity. Combining advantages of fluorescence and SERS allows these dual modal nanostructures to be used

  4. A higher performance dye-sensitized solar cell based on the modified PMII/EMIMBF4 binary room temperature ionic liquid electrolyte

    NASA Astrophysics Data System (ADS)

    Wang, Wu-yang; Cao, Da-peng; Wang, Chao; Zhang, Xiang-yu; Mi, Bao-xiu; Gao, Zhi-qiang; Liang, Zhong-cheng

    2016-07-01

    Additives and iodine (I2) are used to modify the binary room temperature ionic liquid (RTIL) electrolyte to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs). The short-circuit current density ( J SC) of 17.89 mA/cm2, open circuit voltage ( V OC) of 0.71 V and fill factor ( FF) of 0.50 are achieved in the optimal device. An average photoelectric conversion efficiency ( PCE) of 6.35% is achieved by optimization, which is over two times larger than that of the parent device before optimization (2.06%), while the maximum PCE can reach up to 6.63%.

  5. Preparation and characterization of nontoxic magnetic-luminescent nanoprobe

    NASA Astrophysics Data System (ADS)

    Yin, Nai-Qiang; Liu, Ling; Lei, Jie-Mei; Liu, Yan-Song; Gong, Mao-Gang; Wu, Yi-Zhi; Zhu, Li-Xin; Xu, Xiao-Liang

    2012-11-01

    A novel nontoxic, magnetic, and luminescent nanoprobe is prepared by using complex nanoparticles, which are composed of Fe3O4 nanoparticles and Mn-doped ZnS quantum dots (QDs). The nanocomposite probe can provide visible optical and magnetic resonance images simultaneously. Compared with the previously toxic cadmium and mercury based QDs, the superiority of the Mn-doped ZnS QDs is little virulence. The structure and the properties of the particles are characterized by energy dispersive X-ray analysis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and vibrating sample magnetometer.

  6. High-resolution fluorescence mapping of impurities in historical zinc oxide pigments: hard X-ray nanoprobe applications to the paints of Pablo Picasso

    NASA Astrophysics Data System (ADS)

    Casadio, Francesca; Rose, Volker

    2013-04-01

    Here for the first time we describe the use of high resolution nanoprobe X-ray fluorescence (XRF) mapping for the analysis of artists' paints, hierarchically complex materials typically composed of binder, pigments, fillers, and other additives. The work undertaken at the nanoprobe sought to obtain highly spatially resolved, highly sensitive mapping of metal impurities (Pb, Cd, Fe, and other metals) in submicron particles of zinc oxide pigments used in early 20th century artists' tube paints and enamel paints, with particular emphasis on Ripolin, a popular brand of French house paint used extensively by Pablo Picasso and some of his contemporaries. Analysis revealed that the Zn oxide particles only contain a little Fe, proving that the highest quality Zn oxide pigment, free of Pb and Cd, was used for Ripolin house paints as well as artists' paints. Nanoprobe XRF mapping also demonstrated that artists' tube paints generally have more abundant fillers and additional whites (based on Pb, Ti, Ca) than Ripolin paints, which contain mostly pure zinc oxide. The chemical characterization of paints at the nanoscale opens the path to a better understanding of their fabrication and chemical reactivity.

  7. Nanoprobe-Enhanced, Split Aptamer-Based Electrochemical Sandwich Assay for Ultrasensitive Detection of Small Molecules.

    PubMed

    Zhao, Tao; Liu, Ran; Ding, Xiaofan; Zhao, Juncai; Yu, Haixiang; Wang, Lei; Xu, Qing; Wang, Xuan; Lou, Xinhui; He, Miao; Xiao, Yi

    2015-08-01

    It is quite challenging to improve the binding affinity of antismall molecule aptamers. We report that the binding affinity of anticocaine split aptamer pairs improved by up to 66-fold by gold nanoparticles (AuNP)-attached aptamers due to the substantially increased local concentration of aptamers and multiple and simultaneous ligand interactions. The significantly improved binding affinity enables the detection of small molecule targets with unprecedented sensitivity, as demonstrated in nanoprobe-enhanced split aptamer-based electrochemical sandwich assays (NE-SAESA). NE-SAESA replaces the traditional molecular reporter probe with AuNPs conjugated to multiple reporter probes. The increased binding affinity allowed us to use 1,000-fold lower reporter probe concentrations relative to those employed in SAESA. We show that the near-elimination of background in NE-SAESA effectively improves assay sensitivity by ∼1,000-100,000-fold for ATP and cocaine detection, relative to equivalent SAESA. With the ongoing development of new strategies for the selection of aptamers, we anticipate that our sensor platform should offer a generalizable approach for the high-sensitivity detection of diverse targets. More importantly, we believe that NE-SAESA represents a novel strategy to improve the binding affinity between a small molecule and its aptamer and potentially can be extended to other detection platforms. PMID:26171721

  8. Solid-phase single molecule biosensing using dual-color colocalization of fluorescent quantum dot nanoprobes

    NASA Astrophysics Data System (ADS)

    Liu, Jianbo; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Liu, Wei; Wang, Dong

    2013-10-01

    The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to the QD560-TBA I substrate. Thus, the presence of the target thrombin can be determined based on fluorescent colocalization measurements of the nanoassemblies, without target amplification or probe separation. The detection limit of this assay reached 0.8 pM. This fluorescent colocalization assay has enabled single molecule recognition in a separation-free detection format, and can serve as a sensitive biosensing platform that greatly suppresses the nonspecific adsorption false-positive signal. This method can be extended to other areas such as multiplexed immunoassay, single cell analysis, and real time biomolecule interaction studies.The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to

  9. Photostimulable Near-Infrared Persistent Luminescent Nanoprobes for Ultrasensitive and Longitudinal Deep-Tissue Bio-Imaging

    PubMed Central

    Chuang, Yen-Jun; Zhen, Zipeng; Zhang, Fan; Liu, Feng; Mishra, Jyoti P.; Tang, Wei; Chen, Hongmin; Huang, Xinglu; Wang, Lianchun; Chen, Xiaoyuan; Xie, Jin; Pan, Zhengwei

    2014-01-01

    In vivo fluorescence imaging suffers from suboptimal signal-to-noise ratio and shallow detection depth, which is caused by the strong tissue autofluorescence under constant external excitation and the scattering and absorption of short-wavelength light in tissues. Here we address these limitations by using a novel type of optical nanoprobes, photostimulable LiGa5O8:Cr3+ near-infrared (NIR) persistent luminescence nanoparticles, which, with very-long-lasting NIR persistent luminescence and unique photo-stimulated persistent luminescence (PSPL) capability, allow optical imaging to be performed in an excitation-free and hence, autofluorescence-free manner. LiGa5O8:Cr3+ nanoparticles pre-charged by ultraviolet light can be repeatedly (>20 times) stimulated in vivo, even in deep tissues, by short-illumination (~15 seconds) with a white light-emitting-diode flashlight, giving rise to multiple NIR PSPL that expands the tracking window from several hours to more than 10 days. Our studies reveal promising potential of these nanoprobes in cell tracking and tumor targeting, exhibiting exceptional sensitivity and penetration that far exceed those afforded by conventional fluorescence imaging. PMID:25285164

  10. Directly interrogating single quantum dot labelled UvrA2 molecules on DNA tightropes using an optically trapped nanoprobe

    PubMed Central

    Simons, Michelle; Pollard, Mark R.; Hughes, Craig D.; Ward, Andrew D.; Van Houten, Bennett; Towrie, Mike; Botchway, Stan W.; Parker, Anthony W.; Kad, Neil M.

    2015-01-01

    In this study we describe a new methodology to physically probe individual complexes formed between proteins and DNA. By combining nanoscale, high speed physical force measurement with sensitive fluorescence imaging we investigate the complex formed between the prokaryotic DNA repair protein UvrA2 and DNA. This approach uses a triangular, optically-trapped “nanoprobe” with a nanometer scale tip protruding from one vertex. By scanning this tip along a single DNA strand suspended between surface-bound micron-scale beads, quantum-dot tagged UvrA2 molecules bound to these ‘”DNA tightropes” can be mechanically interrogated. Encounters with UvrA2 led to deflections of the whole nanoprobe structure, which were converted to resistive force. A force histogram from all 144 detected interactions generated a bimodal distribution centered on 2.6 and 8.1 pN, possibly reflecting the asymmetry of UvrA2’s binding to DNA. These observations successfully demonstrate the use of a highly controllable purpose-designed and built synthetic nanoprobe combined with fluorescence imaging to study protein-DNA interactions at the single molecule level. PMID:26691010

  11. Photostimulable near-infrared persistent luminescent nanoprobes for ultrasensitive and longitudinal deep-tissue bio-imaging.

    PubMed

    Chuang, Yen-Jun; Zhen, Zipeng; Zhang, Fan; Liu, Feng; Mishra, Jyoti P; Tang, Wei; Chen, Hongmin; Huang, Xinglu; Wang, Lianchun; Chen, Xiaoyuan; Xie, Jin; Pan, Zhengwei

    2014-01-01

    In vivo fluorescence imaging suffers from suboptimal signal-to-noise ratio and shallow detection depth, which is caused by the strong tissue autofluorescence under constant external excitation and the scattering and absorption of short-wavelength light in tissues. Here we address these limitations by using a novel type of optical nanoprobes, photostimulable LiGa5O8:Cr(3+) near-infrared (NIR) persistent luminescence nanoparticles, which, with very-long-lasting NIR persistent luminescence and unique photo-stimulated persistent luminescence (PSPL) capability, allow optical imaging to be performed in an excitation-free and hence, autofluorescence-free manner. LiGa5O8:Cr(3+) nanoparticles pre-charged by ultraviolet light can be repeatedly (>20 times) stimulated in vivo, even in deep tissues, by short-illumination (~15 seconds) with a white light-emitting-diode flashlight, giving rise to multiple NIR PSPL that expands the tracking window from several hours to more than 10 days. Our studies reveal promising potential of these nanoprobes in cell tracking and tumor targeting, exhibiting exceptional sensitivity and penetration that far exceed those afforded by conventional fluorescence imaging. PMID:25285164

  12. Multifunctional hydrogel nano-probes for atomic force microscopy

    PubMed Central

    Lee, Jae Seol; Song, Jungki; Kim, Seong Oh; Kim, Seokbeom; Lee, Wooju; Jackman, Joshua A.; Kim, Dongchoul; Cho, Nam-Joon; Lee, Jungchul

    2016-01-01

    Since the invention of the atomic force microscope (AFM) three decades ago, there have been numerous advances in its measurement capabilities. Curiously, throughout these developments, the fundamental nature of the force-sensing probe—the key actuating element—has remained largely unchanged. It is produced by long-established microfabrication etching strategies and typically composed of silicon-based materials. Here, we report a new class of photopolymerizable hydrogel nano-probes that are produced by bottom-up fabrication with compressible replica moulding. The hydrogel probes demonstrate excellent capabilities for AFM imaging and force measurement applications while enabling programmable, multifunctional capabilities based on compositionally adjustable mechanical properties and facile encapsulation of various nanomaterials. Taken together, the simple, fast and affordable manufacturing route and multifunctional capabilities of hydrogel AFM nano-probes highlight the potential of soft matter mechanical transducers in nanotechnology applications. The fabrication scheme can also be readily utilized to prepare hydrogel cantilevers, including in parallel arrays, for nanomechanical sensor devices. PMID:27199165

  13. EGFR-specific nanoprobe biodistribution in mouse models

    NASA Astrophysics Data System (ADS)

    Fashir, Samia A.; Castilho, Maiara L.; Hupman, Michael A.; Lee, Christopher L. D.; Raniero, Leandro J.; Alwayn, Ian; Hewitt, Kevin C.

    2015-06-01

    Nanotechnology offers a targeted approach to both imaging and treatment of cancer, the leading cause of death worldwide. Previous studies have found nanoparticles with a wide variety of coatings initiate an immune response leading to sequestration in the liver and spleen. In an effort to find a nanoparticle platform which does not elicit an immune response we created 43/44 nm gold or silver nanoparticles coated with biomolecules normally produced by the body, α-lipoic acid and the Epidermal Growth Factor (EGF), and have used mass spectroscopy to determine their biodistribution in mouse models, 24 hours following tail vein injection. Relative to controls, mouse EGF (mEGF) coated silver and gold nanoprobes are found at reduced levels in the liver and spleen. mEGF coated gold nanoprobes on the other hand do not appear to elicit any immune response, as they are found at background levels in these organs. As a result they should remain in circulation for longer and accumulate at high levels in tumors by the enhanced permeability retention (EPR) effect.

  14. Multifunctional hydrogel nano-probes for atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Jae Seol; Song, Jungki; Kim, Seong Oh; Kim, Seokbeom; Lee, Wooju; Jackman, Joshua A.; Kim, Dongchoul; Cho, Nam-Joon; Lee, Jungchul

    2016-05-01

    Since the invention of the atomic force microscope (AFM) three decades ago, there have been numerous advances in its measurement capabilities. Curiously, throughout these developments, the fundamental nature of the force-sensing probe--the key actuating element--has remained largely unchanged. It is produced by long-established microfabrication etching strategies and typically composed of silicon-based materials. Here, we report a new class of photopolymerizable hydrogel nano-probes that are produced by bottom-up fabrication with compressible replica moulding. The hydrogel probes demonstrate excellent capabilities for AFM imaging and force measurement applications while enabling programmable, multifunctional capabilities based on compositionally adjustable mechanical properties and facile encapsulation of various nanomaterials. Taken together, the simple, fast and affordable manufacturing route and multifunctional capabilities of hydrogel AFM nano-probes highlight the potential of soft matter mechanical transducers in nanotechnology applications. The fabrication scheme can also be readily utilized to prepare hydrogel cantilevers, including in parallel arrays, for nanomechanical sensor devices.

  15. Multifunctional hydrogel nano-probes for atomic force microscopy.

    PubMed

    Lee, Jae Seol; Song, Jungki; Kim, Seong Oh; Kim, Seokbeom; Lee, Wooju; Jackman, Joshua A; Kim, Dongchoul; Cho, Nam-Joon; Lee, Jungchul

    2016-01-01

    Since the invention of the atomic force microscope (AFM) three decades ago, there have been numerous advances in its measurement capabilities. Curiously, throughout these developments, the fundamental nature of the force-sensing probe-the key actuating element-has remained largely unchanged. It is produced by long-established microfabrication etching strategies and typically composed of silicon-based materials. Here, we report a new class of photopolymerizable hydrogel nano-probes that are produced by bottom-up fabrication with compressible replica moulding. The hydrogel probes demonstrate excellent capabilities for AFM imaging and force measurement applications while enabling programmable, multifunctional capabilities based on compositionally adjustable mechanical properties and facile encapsulation of various nanomaterials. Taken together, the simple, fast and affordable manufacturing route and multifunctional capabilities of hydrogel AFM nano-probes highlight the potential of soft matter mechanical transducers in nanotechnology applications. The fabrication scheme can also be readily utilized to prepare hydrogel cantilevers, including in parallel arrays, for nanomechanical sensor devices. PMID:27199165

  16. First principle study of the sensitivity of CO adsorption on pure and binary clusters of lead and silicon

    NASA Astrophysics Data System (ADS)

    Narayan Samanta, Pabitra; Das, Kalyan Kumar

    2014-07-01

    The interactions of a CO molecule with pure and binary clusters of Pb and Si up to five atoms are theoretically investigated. The lowest-energy isomers of metal cluster carbonyl complexes are obtained by global optimization of the potential energy hypersurface using Monte Carlo simulation coupled with simulated annealing followed by pseudopotential based plane wave density functional theory (DFT) calculations, and then by local optimization using hybrid DFT calculations at the B3LYP/ aug-cc-pVTZ-pp level of theory. The CO binding energies and Gibbs free energy changes (ΔG) are computed to determine the kinetic and thermodynamic stability of the metal cluster-CO complexes. The variations of adsorption energy, HOMO-LUMO energy gap, and NBO charge on the CO fragment with the size of the metal clusters are reported. The linear correlations among different parameters such as C-O bond elongation, changes in the C-O stretching frequency, and NBO charge on CO are established to confirm the CO adsorption on various pure and binary clusters of Pb and Si. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-40750-2

  17. Fluorescent and Bioluminescent Nanoprobes for In Vitro and In Vivo Detection of Matrix Metalloproteinase Activity.

    PubMed

    Lee, Hawon; Kim, Young-Pil

    2015-06-01

    Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade the extracellular matrix (ECM) and regulate the extracellular microenvironment. Despite the significant role that MMP activity plays in cell-cell and cell-ECM interactions, migration, and differentiation, analyses of MMPs in vitro and in vivo have relied upon their abundance using conventional immunoassays, rather than their enzymatic activities. To resolve this issue, diverse nanoprobes have emerged and proven useful as effective activity-based detection tools. Here, we review the recent advances in luminescent nanoprobes and their applications in in vitro diagnosis and in vivo imaging of MMP activity. Nanoprobes with the purpose of sensing MMP activity consist of recognition and detection units, which include MMP-specific substrates and luminescent (fluorescent or bioluminescent) nanoparticles, respectively. With further research into improvement of the optical performance, it is anticipated that luminescent nanoprobes will have great potential for the study of the functional roles of proteases in cancer biology and nanomedicine. PMID:25817215

  18. Rational design of a bisphenol A aptamer selective surface-enhanced Raman scattering nanoprobe.

    PubMed

    Marks, Haley L; Pishko, Michael V; Jackson, George W; Coté, Gerard L

    2014-12-01

    Surface-enhanced Raman scattering (SERS) optical nanoprobes offer a number of advantages for ultrasensitive analyte detection. These functionalized colloidal nanoparticles are a multifunctional assay component. providing a platform for conjugation to spectral tags, stabilizing polymers, and biorecognition elements such as aptamers or antibodies. We demonstrate the design and characterization of a SERS-active nanoprobe and investigate the nanoparticles' biorecognition capabilities for use in a competitive binding assay. Specifically, the nanoprobe is designed for the quantification of bisphenol A (BPA) levels in the blood after human exposure to the toxin in food and beverage plastic packaging. The nanoprobes demonstrated specific affinity to a BPA aptamer with a dissociation constant Kd of 54 nM, and provided a dose-dependent SERS spectra with a limit of detection of 3 nM. Our conjugation approach shows the versatility of colloidal nanoparticles in assay development, acting as detectable spectral tagging elements and biologically active ligands concurrently. PMID:25329684

  19. Rational Design of a Bisphenol A Aptamer Selective Surface-Enhanced Raman Scattering Nanoprobe

    PubMed Central

    2015-01-01

    Surface-enhanced Raman scattering (SERS) optical nanoprobes offer a number of advantages for ultrasensitive analyte detection. These functionalized colloidal nanoparticles are a multifunctional assay component. providing a platform for conjugation to spectral tags, stabilizing polymers, and biorecognition elements such as aptamers or antibodies. We demonstrate the design and characterization of a SERS-active nanoprobe and investigate the nanoparticles’ biorecognition capabilities for use in a competitive binding assay. Specifically, the nanoprobe is designed for the quantification of bisphenol A (BPA) levels in the blood after human exposure to the toxin in food and beverage plastic packaging. The nanoprobes demonstrated specific affinity to a BPA aptamer with a dissociation constant Kd of 54 nM, and provided a dose-dependent SERS spectra with a limit of detection of 3 nM. Our conjugation approach shows the versatility of colloidal nanoparticles in assay development, acting as detectable spectral tagging elements and biologically active ligands concurrently. PMID:25329684

  20. Mobile based gold nanoprobe TB diagnostics for point-of-need.

    PubMed

    Veigas, B; Fortunato, E; Baptista, P V

    2015-01-01

    Nanotechnology based diagnostics has provided improved tools for pathogen detection and sensitive and specific characterization of antibiotic resistance signatures. Tuberculosis (TB) is caused by members of the Mycobacterium tuberculosis Complex (MTBC) and, according to the World Health Organization, is one of the most serious infectious diseases in the world. Recent advances in molecular diagnostics of TB have improved both the detection time and sensitivity but they still require specialized technical personnel and cumbersome laboratory equipment. Diagnostics at point-of-need is crucial to TB control as it may provide rapid identification of pathogen together with the resistance profile of TB strains, originated from single nucleotide polymorphisms (SNPs) in different loci, allowing for a more accurate indication of the adequate therapy.Gold nanoparticles have been widely used in molecular diagnostics platforms. Here, we describe the use of gold nanoprobes (oligonucleotide functionalized gold nanoparticles) to be used in a non-cross-linking colorimetric method for the direct detection of specific DNA targets. Due to the remarkable optical properties of gold nanoparticles, this detection system provides colorimetric detection of the pathogen together with the potential of identification of several single nucleotide polymorphisms (SNPs) involved in TB resistance to antibiotics. For point-of-need use, we adapted this strategy to a low-cost mobile scheme using a paper based revelation platform and where the spectral signature is transposed to RGB data via a smartphone device. This way, identification of pathogen and characterization of resistance signatures is achieved at point-of-need. PMID:25626530

  1. Dextran-coated gold nanoprobes for the concentration and detection of protein biomarkers.

    PubMed

    Chiu, Ricky Y T; Nguyen, Phuong T; Wang, Juntian; Jue, Erik; Wu, Benjamin M; Kamei, Daniel T

    2014-11-01

    The lateral-flow immunoassay (LFA) is a well-established point-of-care detection assay that is rapid, inexpensive, easy to use, and portable. However, its sensitivity is lower than that of traditional lab-based assays. Previously, we improved the sensitivity of LFA by concentrating the target biomolecules using aqueous two-phase systems (ATPSs) prior to their detection. In this study, we report the first-ever utilization of dextran-coated gold nanoprobes (DGNPs) as the colorimetric indicator for LFA. In addition, the DGNPs are the key component in our pre-concentration process, where they remain stable and functional in the high salt environment of our ATPS solution, capture the target protein with conjugated antibodies, and allow the rapid concentration of the target protein in our ATPS for use in the subsequent LFA detection step. By combining this pre-concentration step with LFA, the detection limit of LFA for a model protein was improved by 10-fold. We further improved our ATPS from previous studies by enabling phase separation at room temperature in 30 min. By using DGNPs for the concentration and detection of protein biomarkers in the sequential combination of the ATPS and LFA steps, we move closer to developing an effective protein detection assay which uses no power or lab-based equipment. PMID:24874602

  2. Nanotubes as nanoprobes in scanning probe microscopy

    NASA Astrophysics Data System (ADS)

    Dai, Hongjie; Hafner, Jason H.; Rinzler, Andrew G.; Colbert, Daniel T.; Smalley, Richard E.

    1996-11-01

    SINCE the invention of the scanning tunnelling microscope1, the value of establishing a physical connection between the macroscopic world and individual nanometre-scale objects has become increasingly evident, both for probing these objects2-4 and for direct manipulation5-7 and fabrication8-10 at the nanometre scale. While good progress has been made in controlling the position of the macroscopic probe of such devices to sub-ångström accuracy, and in designing sensitive detection schemes, less has been done to improve the probe tip itself4. Ideally the tip should be as precisely defined as the object under investigation, and should maintain its integrity after repeated use not only in high vacuum but also in air and water. The best tips currently used for scanning probe microscopy do sometimes achieve sub-nanometre resolution, but they seldom survive a 'tip crash' with the surface, and it is rarely clear what the atomic configuration of the tip is during imaging. Here we show that carbon nanotubes11,12 might constitute well defined tips for scanning probe microscopy. We have attached individual nanotubes several micrometres in length to the silicon cantilevers of conventional atomic force microscopes. Because of their flexibility, the tips are resistant to damage from tip crashes, while their slenderness permits imaging of sharp recesses in surface topography. We have also been able to exploit the electrical conductivity of nanotubes by using them for scanning tunnelling microscopy.

  3. Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes

    NASA Astrophysics Data System (ADS)

    Wang, Hsin-Neng; Vo-Dinh, Tuan

    2009-02-01

    We have demonstrated for the first time the feasibility of multiplex detection using the surface-enhanced Raman scattering-based molecular sentinel (MS) technology in a homogeneous solution. Two MS nanoprobes tagged with different Raman labels were used to detect the presence of the erbB-2 and ki-67 breast cancer biomarkers. The multiplexing capability of the MS technique was demonstrated by mixing the two MS nanoprobes and tested in the presence of single or multiple DNA targets.

  4. A Prodrug-type, MMP-2-targeting Nanoprobe for Tumor Detection and Imaging

    PubMed Central

    Wang, Yaping; Lin, Tingting; Zhang, Wenyuan; Jiang, Yifan; Jin, Hongyue; He, Huining; Yang, Victor C.; Chen, Yi; Huang, Yongzhuo

    2015-01-01

    Tumor-associated proteases (TAPs) have been intensively studied because of their critical roles in cancer development. As a case in point, expression of matrix metalloproteases (MMP) is significantly up-regulated in tumorigenesis, invasion, and metastasis among a majority of cancers. Here we present a prodrug-type, MMP-2-responsive nanoprobe system with high efficiency and low toxicity for detecting MMP-2-overexpressed tumors. The nanoprobe system is featured by its self-assembled fabrication and FRET effect. This prodrug-type nanoprobe is selectively activated by MMP-2, and thus useful for detection of the MMP-2-overexpressed cells and tumors. The nanoprobe system works successfully in various animal tumor models, including human fibrosarcoma and subcutaneous glioma xenograft. Furthermore, in order to overcome the blood brain barrier (BBB) and achieve brain tumor targeting, a transferrin-receptor targeting peptide (T7 peptide) is strategically incorporated into the nanoprobe. The T7-functionalized nanoprobe is capable of detecting the orthotopic brain tumor, with clear, real-time in vivo imaging. This method is promising for in vivo detection of brain tumor, and real-time monitor of a TAP (i.e., MMP-2). PMID:26000052

  5. Biomolecular environment, quantification, and intracellular interaction of multifunctional magnetic SERS nanoprobes.

    PubMed

    Büchner, Tina; Drescher, Daniela; Merk, Virginia; Traub, Heike; Guttmann, Peter; Werner, Stephan; Jakubowski, Norbert; Schneider, Gerd; Kneipp, Janina

    2016-08-15

    Multifunctional composite nanoprobes consisting of iron oxide nanoparticles linked to silver and gold nanoparticles, Ag-Magnetite and Au-Magnetite, respectively, were introduced by endocytic uptake into cultured fibroblast cells. The cells containing the non-toxic nanoprobes were shown to be displaceable in an external magnetic field and can be manipulated in microfluidic channels. The distribution of the composite nanostructures that are contained in the endosomal system is discussed on the basis of surface-enhanced Raman scattering (SERS) mapping, quantitative laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) micromapping, and cryo soft X-ray tomography (cryo soft-XRT). Cryo soft-XRT of intact, vitrified cells reveals that the composite nanoprobes form intra-endosomal aggregates. The nanoprobes provide SERS signals from the biomolecular composition of their surface in the endosomal environment. The SERS data indicate the high stability of the nanoprobes and of their plasmonic properties in the harsh environment of endosomes and lysosomes. The spectra point at the molecular composition at the surface of the Ag-Magnetite and Au-Magnetite nanostructures that is very similar to that of other composite structures, but different from the composition of pure silver and gold SERS nanoprobes used for intracellular investigations. As shown by the LA-ICP-MS data, the uptake efficiency of the magnetite composites is approximately two to three times higher than that of the pure gold and silver nanoparticles. PMID:27353290

  6. A Novel Nanoprobe for Multimodal Imaging Is Effectively Incorporated into Human Melanoma Metastatic Cell Lines

    PubMed Central

    Aasen, Synnøve Nymark; Pospisilova, Aneta; Eichler, Tilo Wolf; Panek, Jiri; Hruby, Martin; Stepanek, Petr; Spriet, Endy; Jirak, Daniel; Skaftnesmo, Kai Ove; Thorsen, Frits

    2015-01-01

    To facilitate efficient drug delivery to tumor tissue, several nanomaterials have been designed, with combined diagnostic and therapeutic properties. In this work, we carried out fundamental in vitro and in vivo experiments to assess the labeling efficacy of our novel theranostic nanoprobe, consisting of glycogen conjugated with a red fluorescent probe and gadolinium. Microscopy and resazurin viability assays were used to study cell labeling and cell viability in human metastatic melanoma cell lines. Fluorescence lifetime correlation spectroscopy (FLCS) was done to investigate nanoprobe stability. Magnetic resonance imaging (MRI) was performed to study T1 relaxivity in vitro, and contrast enhancement in a subcutaneous in vivo tumor model. Efficient cell labeling was demonstrated, while cell viability, cell migration, and cell growth was not affected. FLCS showed that the nanoprobe did not degrade in blood plasma. MRI demonstrated that down to 750 cells/μL of labeled cells in agar phantoms could be detected. In vivo MRI showed that contrast enhancement in tumors was comparable between Omniscan contrast agent and the nanoprobe. In conclusion, we demonstrate for the first time that a non-toxic glycogen-based nanoprobe may effectively visualize tumor cells and tissue, and, in future experiments, we will investigate its therapeutic potential by conjugating therapeutic compounds to the nanoprobe. PMID:26370983

  7. Zooming in on a sleeping giant: milliarcsecond High Sensitivity Array imaging of the black hole binary V404 Cyg in quiescence

    NASA Astrophysics Data System (ADS)

    Miller-Jones, J. C. A.; Gallo, E.; Rupen, M. P.; Mioduszewski, A. J.; Brisken, W.; Fender, R. P.; Jonker, P. G.; Maccarone, T. J.

    2008-08-01

    Observations of the black hole X-ray binary V404 Cyg with the very long baseline interferometer the High Sensitivity Array (HSA) have detected the source at a frequency of 8.4GHz, providing a source position accurate to 0.3mas relative to the calibrator source. The observations put an upper limit of 1.3mas on the source size (5.2au at 4kpc) and a lower limit of 7 × 106 K on its brightness temperature during the normal quiescent state, implying that the radio emission must be non-thermal, most probably synchrotron radiation, possibly from a jet. The radio light curves show a short flare, with a rise time of ~30min, confirming that the source remains active in the quiescent state.

  8. FITC-quencher based caspase 3-activatable nanoprobes for effectively sensing caspase 3 in vitro and in cells

    NASA Astrophysics Data System (ADS)

    Tang, Anming; Mei, Bin; Wang, Weijuan; Hu, Wanglai; Li, Fang; Zhou, Jun; Yang, Qing; Cui, Hua; Wu, Mian; Liang, Gaolin

    2013-09-01

    By employing fluorescence resonance energy transfer (FRET) quenching, we rationally designed two new FITC-quencher based nanoprobes for effectively sensing caspase 3 (Casp3) in vitro and in cells. Our nanoprobes hold promise for assessing the chemotherapeutic effect of cancer treatment.By employing fluorescence resonance energy transfer (FRET) quenching, we rationally designed two new FITC-quencher based nanoprobes for effectively sensing caspase 3 (Casp3) in vitro and in cells. Our nanoprobes hold promise for assessing the chemotherapeutic effect of cancer treatment. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03339b

  9. Quantum Dot-Based Nanoprobes for In Vivo Targeted Imaging

    PubMed Central

    Zhu, Yian; Hong, Hao; Xu, Zhi Ping; Li, Zhen; Cai, Weibo

    2013-01-01

    Fluorescent semiconductor quantum dots (QDs) have attracted tremendous attention over the last decade. The superior optical properties of QDs over conventional organic dyes make them attractive labels for a wide variety of biomedical applications, whereas their potential toxicity and instability in biological environment has puzzled scientific researchers. Much research effort has been devoted to surface modification and functionalization of QDs to make them versatile probes for biomedical applications, and significant progress has been made over the last several years. This review article aims to describe the current state-of-the-art of the synthesis, modification, bioconjugation, and applications of QDs for in vivo targeted imaging. In addition, QD-based multifunctional nanoprobes are also summarized. PMID:24206136

  10. Preparation and Characterization of Bimodal Magnetofluorescent Nanoprobes for Biomedical Application

    NASA Astrophysics Data System (ADS)

    Lei, Jie-Mei; Xu, Xiao-Liang; Liu, Ling; Yin, Nai-Qiang; Zhu, Li-Xin

    2012-09-01

    Magnetic-fluorescent bifunctional Fe3O4/SiO2-CdTeS nanocomposites are synthesized. Fe3O4 superparamagnetic nanoparticles are firstly prepared through the thermal decomposition of Fe oleate precursors and coated with a mesoporous silica shell using the Stöber method, and the silica surface is then modified with positively charged amino groups by adding 3-aminopropyltrimethoxysilane. Finally, negatively charged CdTeS quantum dots are linked and assembled onto the positively charged surface of Fe3O4/SiO2 through electrostatic interactions. X-ray diffraction, transmission electron microscopy, photoluminescence spectroscopy, and magnetometry are applied to characterize the nanocomposites. The results show that the bifunctional nanocomposites combine the optical properties of near-infrared CdTeS quantum dots with the superparamagnetic properties of Fe3O4 perfectly, expressing the potential application as a biocompatible magnetofuorescent nanoprobe for in vivo labelling.

  11. Quantum dot-based nanoprobes for in vivo targeted imaging.

    PubMed

    Zhu, Y; Hong, H; Xu, Z P; Li, Z; Cai, W

    2013-12-01

    Fluorescent semiconductor quantum dots (QDs) have attracted tremendous attention over the last decade. The superior optical properties of QDs over conventional organic dyes make them attractive labels for a wide variety of biomedical applications, whereas their potential toxicity and instability in biological environment have puzzled scientific researchers. Much research effort has been devoted to surface modification and functionalization of QDs to make them versatile probes for biomedical applications, and significant progress has been made over the last several years. This review article aims to describe the current state-of-the-art of the synthesis, modification, bioconjugation, and applications of QDs for in vivo targeted imaging. In addition, QD-based multifunctional nanoprobes are also summarized. PMID:24206136

  12. Nonlinear nanoprobes for characterizing ultrafast optical near field

    NASA Astrophysics Data System (ADS)

    Li, Haifeng

    With the rapid development of ultrafast optics and nanophotonics, it is crucial to measure the spatiotemporal evolution of an ultrafast optical near field in nanometer spatial and femtosecond temporal resolution with minimal perturbation. Although near-field scanning optical microscopy (NSOM) can achieve nanoscale spatial resolution and various ultrashort pulse diagnostic tools can characterize femtosecond laser pulses, yet such capability to noninvasively characterize the nanoscale characteristics of femtosecond pulses in all three spatial dimensions remains elusive. In this dissertation, we developed different types of nonlinear optical probes to characterize ultrashort optical pulses. The nonlinear optical probe is composed of three parts, a silica fiber taper, a single nanowire bonded to the end of the fiber and nonlinear nanoparticles attached on the tip of the nanowire. The optical fiber taper can be readily mounted on a mechanical stage and served as a macroscopic interface for handling and positioning control. The single nanowire bridges the dimension gap between the nanocrystals and the fiber taper, and is critical for achieving large aspect ratio and hence minimizing optical scattering and perturbation. The nonlinear nanoparticles give rise to its capability to characterize ultrashort optical pulses. The unique fusion of nanoscale and nonlinear features in developed nonlinear optical probes provides the ability of probing ultrafast optical field in complex 3D microand nano- structures. The demonstration of such ability is crucial for understanding the interaction of ultrafast optical fields and nanoscale systems. The fabrication processes of the nonlinear optical probes are illustrated in detail and the optical properties of the probes are investigated. Two different types of nonlinear optical probes, two-photon fluorescent nanoprobes and Second HARmonic nanoProbes (SHARP), are fabricated. Interferometric autocorrelation measurements near the focal point

  13. PEG-Like Nanoprobes: Multimodal, Pharmacokinetically and Optically Tunable Nanomaterials

    PubMed Central

    Guo, Yanyan; Yuan, Hushan; Claudio, Natalie M.; Kura, Sreekanth; Shakerdge, Naomi; Mempel, Thorsten R.; Bacskai, Brian J.; Josephson, Lee

    2014-01-01

    “PEG-like Nanoprobes” (PN’s) are pharmacokinetically and optically tunable nanomaterials whose disposition in biological systems can be determined by fluorescence or radioactivity. PN’s feature a unique design where a single PEG polymer surrounds a short fluorochrome and radiometal bearing peptide, and endows the resulting nanoprobe with pharmacokinetic control (based on molecular weight of the PEG selected) and optical tunability (based on the fluorochrome selected), while the chelate provides a radiolabeling option. PN’s were used to image brain capillary angiography (intravital 2-photon microscopy), tumor capillary permeability (intravital fluorescent microscopy), and the tumor enhanced permeability and retention (EPR) effect (111In-PN and SPECT). Clinical applications of PN’s include use as long blood half-life fluorochromes for intraoperative angiography, for measurements of capillary permeability in breast cancer lesions, and to image EPR by SPECT, for stratifying patient candidates for long-circulating nanomedicines that may utilize the EPR mechanism. PMID:24781778

  14. Design of Metalloporphyrin-Based Dendritic Nanoprobes for Two-Photon Microscopy of Oxygen

    PubMed Central

    Lebedev, Artem Y.; Troxler, Thomas; Vinogradov, Sergei A.

    2009-01-01

    Metalloporphyrin-based phosphorescent nanoprobes are being developed for two-photon microscopy of oxygen. In these molecular constructs generation of porphyrin triplet states upon two-photon excitation is induced upon the intramolecular Förster-type resonance energy transfer from a covalently attached 2P antenna. In the earlier developed prototypes, electron transfer between the antenna and the metalloporphyrin strongly interfered with the phosphorescence, reducing the sensitivity and the dynamic range of the sensors. By tuning the distances between the antenna and the core and adjusting their redox potentials the unwanted electron transfer could be prevented. An array of phosphorescent Pt porphyrins (energy transfer acceptors) and 2P dyes (energy transfer donors) was screened using dynamic quenching of phosphorescence, and the FRET-pair with the minimal ET rate was identified. This pair, consisting of Coumarin-343 and Pt meso-tetra-(4-alkoxyphenyl)porphyrin, was used to construct a probe in which the antenna fragments were linked to the termini of G3 poly(arylglycine) (AG) dendrimer with PtP core. The folded dendrimer formed an insulating layer between the porphyrin and the antenna, simultaneously controlling the rate of oxygen quenching (Stern-Volmer oxygen quenching constant). Modification of the dendrimer periphery with oligoethyleneglycol residues made the probe’s signal insensitive to the presence of proteins and other macromolecular solutes. PMID:19763243

  15. Ultrasensitive Detection of Ebola Virus Oligonucleotide Based on Upconversion Nanoprobe/Nanoporous Membrane System.

    PubMed

    Tsang, Ming-Kiu; Ye, WeiWei; Wang, Guojing; Li, Jingming; Yang, Mo; Hao, Jianhua

    2016-01-26

    Ebola outbreaks are currently of great concern, and therefore, development of effective diagnosis methods is urgently needed. The key for lethal virus detection is high sensitivity, since early-stage detection of virus may increase the probability of survival. Here, we propose a luminescence scheme of assay consisting of BaGdF5:Yb/Er upconversion nanoparticles (UCNPs) conjugated with oligonucleotide probe and gold nanoparticles (AuNPs) linked with target Ebola virus oligonucleotide. As a proof of concept, a homogeneous assay was fabricated and tested, yielding a detection limit at picomolar level. The luminescence resonance energy transfer is ascribed to the spectral overlapping of upconversion luminescence and the absorption characteristics of AuNPs. Moreover, we anchored the UCNPs and AuNPs on a nanoporous alumina (NAAO) membrane to form a heterogeneous assay. Importantly, the detection limit was greatly improved, exhibiting a remarkable value at the femtomolar level. The enhancement is attributed to the increased light-matter interaction throughout the nanopore walls of the NAAO membrane. The specificity test suggested that the nanoprobes were specific to Ebola virus oligonucleotides. The strategy combining UCNPs, AuNPs, and NAAO membrane provides new insight into low-cost, rapid, and ultrasensitive detection of different diseases. Furthermore, we explored the feasibility of clinical application by using inactivated Ebola virus samples. The detection results showed great potential of our heterogeneous design for practical application. PMID:26720408

  16. The Bionanoprobe: hard X-ray fluorescence nanoprobe with cryogenic capabilities

    PubMed Central

    Chen, S.; Deng, J.; Yuan, Y.; Flachenecker, C.; Mak, R.; Hornberger, B.; Jin, Q.; Shu, D.; Lai, B.; Maser, J.; Roehrig, C.; Paunesku, T.; Gleber, S. C.; Vine, D. J.; Finney, L.; VonOsinski, J.; Bolbat, M.; Spink, I.; Chen, Z.; Steele, J.; Trapp, D.; Irwin, J.; Feser, M.; Snyder, E.; Brister, K.; Jacobsen, C.; Woloschak, G.; Vogt, S.

    2014-01-01

    Hard X-ray fluorescence microscopy is one of the most sensitive techniques for performing trace elemental analysis of biological samples such as whole cells and tissues. Conventional sample preparation methods usually involve dehydration, which removes cellular water and may consequently cause structural collapse, or invasive processes such as embedding. Radiation-induced artifacts may also become an issue, particularly as the spatial resolution increases beyond the sub-micrometer scale. To allow imaging under hydrated conditions, close to the ‘natural state’, as well as to reduce structural radiation damage, the Bionanoprobe (BNP) has been developed, a hard X-ray fluorescence nanoprobe with cryogenic sample environment and cryo transfer capabilities, dedicated to studying trace elements in frozen-hydrated biological systems. The BNP is installed at an undulator beamline at sector 21 of the Advanced Photon Source. It provides a spatial resolution of 30 nm for two-dimensional fluorescence imaging. In this first demonstration the instrument design and motion control principles are described, the instrument performance is quantified, and the first results obtained with the BNP on frozen-hydrated whole cells are reported. PMID:24365918

  17. Tunneling of redox enzymes to design nano-probes for monitoring NAD(+) dependent bio-catalytic activity.

    PubMed

    Akshath, Uchangi Satyaprasad; Bhatt, Praveena

    2016-11-15

    Monitoring of bio-catalytic events by using nano-probes is of immense interest due to unique optical properties of metal nanoparticles. In the present study, tunneling of enzyme activity was achieved using redox cofactors namely oxidized cytochrome-c (Cyt-c) and Co-enzyme-Q (Co-Q) immobilized on Quantum dots (QDs) which acted as a bio-probe for NAD(+) dependent dehydrogenase catalyzed reaction. We studied how electron transfer from substrate to non-native electron acceptors can differentially modify photoluminescence properties of CdTe QDs. Two probes were designed, QD-Ox-Cyt-c and QD-Ox-Co-Q, which were found to quench the fluorescence of QDs. However, formaldehyde dehydrogenase (FDH) catalyzed reduction of Cyt-c and Co-Q on the surface of QDs lead to fluorescence turn-on of CdTe QDs. This phenomenon was successfully used for the detection of HCHO in the range of 0.01-100,000ng/mL (LOD of 0.01ng/mL) using both QD-Ox-Cyt-c (R(2)=0.93) and QD-Ox-Co-Q (R(2)=0.96). Further probe performance and stability in samples like milk, wine and fruit juice matrix were studied and we could detect HCHO in range of 0.001-100,000ng/mL (LOD of 0.001ng/mL) with good stability and sensitivity of probe in real samples (R(2)=0.97). Appreciable recovery and detection sensitivity in the presence of metal ions suggests that the developed nano-probes can be used successfully for monitoring dehydrogenase based bio-catalytic events even in the absence of NAD(+). Proposed method is advantageous over classical methods as clean up/ derivatization of samples is not required for formaldehyde detection. PMID:27179565

  18. Optimized dendrimer-encapsulated gold nanoparticles and enhanced carbon nanotube nanoprobes for amplified electrochemical immunoassay of E. coli in dairy product based on enzymatically induced deposition of polyaniline.

    PubMed

    Zhang, Xinai; Shen, Jianzhong; Ma, Haile; Jiang, Yuxiang; Huang, Chenyong; Han, En; Yao, Boshui; He, Yunyao

    2016-06-15

    A highly sensitive immunosensor was reported for Escherichia coli assay in dairy product based on electrochemical measurement of polyaniline (PAn) that was catalytically deposited by horseradish peroxidase (HRP) labels. Herein, the immunosensor was developed by using poly(amidoamine) dendrimer-encapsulated gold nanoparticles (PAMAM(Au)) as sensing platform. Importantly, the optimal HAuCl4/PAMAM ratio was investigated to design the efficient PAMAM(Au) nanocomposites. The nanocomposites were proven to not only increase the amount of immobilized capture antibody (cAb), but also accelerate the electron transfer process. Moreover, the {dAb-CNT-HRP} nanoprobes were prepared by exploiting the amplification effect of multiwalled carbon nanotubes (CNTs) for loading detection antibody (dAb) and enormous HRP labels. After a sandwich immunoreaction, the quantitatively captured nanoprobes could catalyze oxidation aniline to produce electroactive PAn for electrochemical measurement. On the basis of signal amplification of the PAMAM(Au)-based immunosensor and the {dAb-CNT-HRP} nanoprobes, the proposed strategy exhibited a linear relationship between the peak current of PAn and the logarithmic value of E. coli concentration ranging from 1.0 × 10(2) to 1.0 × 10(6) cfu mL(-1) with a detection limit of 50 cfu mL(-1) (S/N=3), and the electrochemical detection of E. coli could be achieved in 3h. The electrochemical immunosensor was also used to determine E. coli in dairy product (pure fresh milk, infant milk powder, yogurt in shelf-life and expired yogurt), and the recoveries of standard additions were in the range of 96.8-108.7%. Overall, this method gave a useful protocol for E. coli assay with high sensitivity, acceptable accuracy and satisfying stability, and thus provided a powerful tool to estimate the quality of dairy product. PMID:26908184

  19. In vivo MRI detection of gliomas by chlorotoxin-conjugated superparamagnetic nanoprobes.

    PubMed

    Sun, Conroy; Veiseh, Omid; Gunn, Jonathan; Fang, Chen; Hansen, Stacey; Lee, Donghoon; Sze, Raymond; Ellenbogen, Richard G; Olson, Jim; Zhang, Miqin

    2008-03-01

    Converging advances in the development of nanoparticle-based imaging probes and improved understanding of the molecular biology of brain tumors offer the potential to provide physicians with new tools for the diagnosis and treatment of these deadly diseases. However, the effectiveness of promising nanoparticle technologies is currently limited by insufficient accumulation of these contrast agents within tumors. Here a biocompatible nanoprobe composed of a poly(ethylene glycol) (PEG) coated iron oxide nanoparticle that is capable of specifically targeting glioma tumors via the surface-bound targeting peptide, chlorotoxin (CTX), is presented. The preferential accumulation of the nanoprobe within gliomas and subsequent magnetic resonance imaging (MRI) contrast enhancement are demonstrated in vitro in 9L cells and in vivo in tumors of a xenograft mouse model. TEM imaging reveals that the nanoprobes are internalized into the cytoplasm of 9L cells and histological analysis of selected tissues indicates that there are no acute toxic effects of these nanoprobes. High targeting specificity and benign biological response establish this nanoprobe as a potential platform to aid in the diagnosis and treatment of gliomas and other tumors of neuroectodermal origin. PMID:18232053

  20. SERS-fluorescence joint spectral encoded magnetic nanoprobes for multiplex cancer cell separation.

    PubMed

    Wang, Zhuyuan; Zong, Shenfei; Chen, Hui; Wang, Chunlei; Xu, Shuhong; Cui, Yiping

    2014-11-01

    A new kind of cancer cell separation method is demonstrated, using surface-enhanced Raman scattering (SERS) and fluorescence dual-encoded magnetic nanoprobes. The designed nanoprobes can realize SERS-fluorescence joint spectral encoding (SFJSE) and greatly improve the multiplexing ability. The nanoprobes have four main components, that is, the magnetic core, SERS generator, fluorescent agent, and targeting antibody. These components are assembled with a multi-layered structure to form the nanoprobes. Specifically, silica-coated magnetic nanobeads (MBs) are used as the inner core. Au core-Ag shell nanorods (Au@Ag NRs) are employed as the SERS generators and attached on the silica-coated MBs. After burying these Au@Ag NRs with another silica layer, CdTe quantum dots (QDs), that is, the fluorescent agent, are anchored onto the silica layer. Finally, antibodies are covalently linked to CdTe QDs. SFJSE is fulfilled by using different Raman molecules and QDs with different emission wavelengths. By utilizing four human cancer cell lines and one normal cell line as the model cells, the nanoprobes can specifically and simultaneously separate target cancer cells from the normal ones. This SFJSE-based method greatly facilitates the multiplex, rapid, and accurate cancer cell separation, and has a prosperous potential in high-throughput analysis and cancer diagnosis. PMID:24862088

  1. An efficient core-shell fluorescent silica nanoprobe for ratiometric fluorescence detection of pH in living cells.

    PubMed

    Fu, Jingni; Ding, Changqin; Zhu, Anwei; Tian, Yang

    2016-08-01

    Intracellular pH plays a vital role in cell biology, including signal transduction, ion transport and homeostasis. Herein, a ratiometric fluorescent silica probe was developed to detect intracellular pH values. The pH sensitive dye fluorescein isothiocyanate isomer I (FITC), emitting green fluorescence, was hybridized with reference dye rhodamine B (RB), emitting red fluorescence, as a dual-emission fluorophore, in which RB was embedded in a silica core of ∼40 nm diameter. Moreover, to prevent fluorescence resonance energy transfer between FITC and RB, FITC was grafted onto the surface of core-shell silica colloidal particles with a shell thickness of 10-12 nm. The nanoprobe exhibited dual emission bands centered at 517 and 570 nm, under single wavelength excitation of 488 nm. RB encapsulated in silica was inert to pH change and only served as reference signals for providing built-in correction to avoid environmental effects. Moreover, FITC (λem = 517 nm) showed high selectivity toward H(+) against metal ions and amino acids, leading to fluorescence variation upon pH change. Consequently, variations of the two fluorescence intensities (Fgreen/Fred) resulted in a ratiometric pH fluorescent sensor. The specific nanoprobe showed good linearity with pH variation in the range of 6.0-7.8. It can be noted that the fluorescent silica probe demonstrated good water dispersibility, high stability and low cytotoxicity. Accordingly, imaging and biosensing of pH variation was successfully achieved in HeLa cells. PMID:27291898

  2. Work-function measurement by high-resolution scanning Kelvin nanoprobe

    NASA Astrophysics Data System (ADS)

    Cheran, Larisa-Emilia; Johnstone, Sherri; Sadeghi, Saman; Thompson, Michael

    2007-03-01

    Nanoscience promises to transform today's world in the same way that integrated semiconductor devices transformed the world of electronics and computation. In the post-genomic era, the greatest challenge is to make connections between the structures and functions of biomolecules at the nanometre-scale level in order to underpin the understanding of larger scale systems in the fields of human biology and physiology. To achieve this, instruments with new capabilities need to be researched and developed, with particular emphasis on new levels of sensitivity, precision and resolution for biomolecular analysis. This paper describes an instrument able to analyse structures that range from tenths of a nanometre (proteins, DNA) to micron-scale structures (living cells), which can be investigated non-destructively in their normal state and subsequently in chemical- or biochemical-modified conditions. The high-resolution scanning Kelvin nanoprobe (SKN) measures the work-function changes at molecular level, instigated by local charge reconfiguration due to translational motion of mobile charges, dipolar relaxation of bound charges, interfacial polarization and structural and conformational modifications. In addition to detecting surface electrical properties, the instrument offers, in parallel, the surface topographic image, with nanometre resolution. The instrument can also be used to investigate subtle work function/topography variations which occur in, for example, corrosion, contamination, adsorption and desorption of molecules, crystallographic studies, mechanical stress studies, surface photovoltaic studies, material science, biocompatibility studies, microelectronic characterization in semiconductor technology, oxide and thin films, surface processing and treatments, surfaces and interfaces characterization. This paper presents the design and development of the instrument, the basic principles of the method and the challenges involved to achieve nanometric resolution

  3. Moving graphene devices from lab to market: advanced graphene-coated nanoprobes.

    PubMed

    Hui, Fei; Vajha, Pujashree; Shi, Yuanyuan; Ji, Yanfeng; Duan, Huiling; Padovani, Andrea; Larcher, Luca; Li, Xiao Rong; Xu, Jing Juan; Lanza, Mario

    2016-04-28

    After more than a decade working with graphene there is still a preoccupying lack of commercial devices based on this wonder material. Here we report the use of high-quality solution-processed graphene sheets to fabricate ultra-sharp probes with superior performance. Nanoprobes are versatile tools used in many fields of science, but they can wear fast after some experiments, reducing the quality and increasing the cost of the research. As the market of nanoprobes is huge, providing a solution for this problem should be a priority for the nanotechnology industry. Our graphene-coated nanoprobes not only show enhanced lifetime, but also additional unique properties of graphene, such as hydrophobicity. Moreover, we have functionalized the surface of graphene to provide piezoelectric capability, and have fabricated a nano relay. The simplicity and low cost of this method, which can be used to coat any kind of sharp tip, make it suitable for the industry, allowing production on demand. PMID:26593053

  4. A smart fluorescence nanoprobe for the detection of cellular alkaline phosphatase activity and early osteogenic differentiation.

    PubMed

    Cao, Feng-Yi; Fan, Jin-Xuan; Long, Yue; Zeng, Xuan; Zhang, Xian-Zheng

    2016-07-01

    In the past decades, biomaterials were designed to induce stem cell toward osteogenic differentiation. However, conventional methods for evaluation osteogenic differentiation all required a process of cell fixation or lysis, which induce waste of a large number of cells. In this study, a fluorescence nanoprobe was synthesized by combining phosphorylated fluoresceinamine isomer I (FLA) on the surface of mesoporous silica-coated superparamagnetic iron oxide (Fe3O4@mSiO2) nanoparticles. In the presence of alkaline phosphatase (ALP), the phosphorylated FLA on the nanoprobe would be hydrolyzed, resulting in a fluorescence recovery of FLA. During early osteogenic differentiation, a high-level expression of cellular ALP was induced, which accelerated the hydrolysis of phosphorylated FLA, resulting in an enhancement of cellular fluorescence intensity. This fluorescence nanoprobe provides us a rapid and non-toxic method for the detection of cellular ALP activity and early osteogenic differentiation. PMID:26961462

  5. Bioorthogonal SERS Nanoprobes for Mulitplex Spectroscopic Detection, Tumor Cell Targeting, and Tissue Imaging.

    PubMed

    Wu, Junzhou; Liang, Duanwei; Jin, Qingqing; Liu, Jie; Zheng, Meiling; Duan, Xuanming; Tang, Xinjing

    2015-09-01

    A surface-enhanced Raman scattering (SERS) technique shows extraordinary features for a range of biological and biomedical applications. Herein, a series of novel bioorthogonal SERS nanoprobes were constructed with Gold nanoflower (AuNF) and Raman reporters, the signals of which were located in a Raman-silent region of biological samples. AS1411 aptamer was also co-conjugated with AuNF through a self-assembled monolayer coverage strategy. Multiplex SERS imaging using these nanoprobes with three different bioorthogonal small-molecule Raman reporters is successfully achieved with high multiplexing capacity in a biologically Raman-silent region. These Raman nanoprobes co-conjugated with AS1411 showed high affinity for tumor cells with overexpressed nucleolin and can be used for selective tumor cell screening and tissue imaging. PMID:26222682

  6. Graphene oxide-encoded Ag nanoshells with single-particle detection sensitivity towards cancer cell imaging based on SERRS.

    PubMed

    Yim, DaBin; Kang, Homan; Jeon, Su-Ji; Kim, Hye-In; Yang, Jin-Kyoung; Kang, Tae Wook; Lee, Sangyeop; Choo, Jaebum; Lee, Yoon-Sik; Kim, Jin Woong; Kim, Jong-Ho

    2015-05-21

    Developing ultrasensitive Raman nanoprobes is one of the emerging interests in the field of biosensing and bioimaging. Herein, we constructed a new type of surface-enhanced resonance Raman scattering nanoprobe composed of an Ag nanoshell as a surface-enhanced Raman scattering-active nanostructure, which was encapsulated with 4,7,10-trioxa-1,13-tridecanediamine-functionalized graphene oxide as an ultrasensitive Raman reporter exhibiting strong resonance Raman scattering including distinct D and G modes. The designed nanoprobe was able to produce much more intense and simpler Raman signals even at a single particle level than the Ag nanoshell bearing a well-known Raman reporter, which is beneficial for the sensitive detection of a target in a complex biological system. Finally, this ultrasensitive nanoprobe successfully demonstrated its potential for bioimaging of cancer cells using Raman spectroscopy. PMID:25811703

  7. ZnO light-emitting nanoprobes for tumor detection

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Tsan; Shen, Yi-Chun; Yang, Sheng-Chieh; Yang, Tsung-Lin; Huang, Jian-Jang

    2013-02-01

    Tumor detection is a significant health issue, but it is still a limit to identify cancer cells during tumor resection by using traditional methods such as fluorescence. In this study, zinc oxide (ZnO) nanorods bonded to antibodies was investigated as nanoprobes for sensing cancer cells. The result shows that antibodies toward epidermal growth factor receptor (EGFR) can be connected to ZnO nanorods and EGFR receptors of squamous cell carcinoma (SCC). The cancer cells can be recognized via the observation of purple light emission from these probes by using naked eye or an optical microscope. By contrast, the HS68 cells with less EGFR expression had no purple light emission as the probes were washed off. Besides, from the photoluminescent spectra, the intensity ratio between the purple light (from ZnO nanorods) and green band (from the autofluorescence of cells) is much higher in SCC than in HS68 cells, which suggest that the cancer cells can be detected by comparing the peak intensity ratio. The probes have the potential clinical application for real-time tumor detection, and the cancer cells can be excised more precisely with the help of purple light emission.

  8. Tumor Vascular Permeability to a Nanoprobe Correlates to Tumor-Specific Expression Levels of Angiogenic Markers

    PubMed Central

    Karathanasis, Efstathios; Chan, Leslie; Karumbaiah, Lohitash; McNeeley, Kathleen; D'Orsi, Carl J.; Annapragada, Ananth V.; Sechopoulos, Ioannis; Bellamkonda, Ravi V.

    2009-01-01

    Background Vascular endothelial growth factor (VEGF) receptor-2 is the major mediator of the mitogenic, angiogenic, and vascular hyperpermeability effects of VEGF on breast tumors. Overexpression of VEGF and VEGF receptor-2 is associated with the degree of pathomorphosis of the tumor tissue and unfavorable prognosis. In this study, we demonstrate that non-invasive quantification of the degree of tumor vascular permeability to a nanoprobe correlates with the VEGF and its receptor levels and tumor growth. Methodology/Principal Findings We designed an imaging nanoprobe and a methodology to detect the intratumoral deposition of a 100 nm-scale nanoprobe using mammography allowing measurement of the tumor vascular permeability in a rat MAT B III breast tumor model. The tumor vascular permeability varied widely among the animals. Notably, the VEGF and VEGF receptor-2 gene expression of the tumors as measured by qRT-PCR displayed a strong correlation to the imaging-based measurements of vascular permeability to the 100 nm-scale nanoprobe. This is in good agreement with the fact that tumors with high angiogenic activity are expected to have more permeable blood vessels resulting in high intratumoral deposition of a nanoscale agent. In addition, we show that higher intratumoral deposition of the nanoprobe as imaged with mammography correlated to a faster tumor growth rate. This data suggest that vascular permeability scales to the tumor growth and that tumor vascular permeability can be a measure of underlying VEGF and VEGF receptor-2 expression in individual tumors. Conclusions/Significance This is the first demonstration, to our knowledge, that quantitative imaging of tumor vascular permeability to a nanoprobe represents a form of a surrogate, functional biomarker of underlying molecular markers of angiogenesis. PMID:19513111

  9. Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system.

    PubMed

    Bandara, T M W J; Dissanayake, M A K L; Jayasundara, W J M J S R; Albinsson, I; Mellander, B-E

    2012-06-28

    Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex4N(+)I(-)) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex4N(+)I(-) with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 × 10(-3) S cm(-1) at 25 °C, and a glass transition at -102.4 °C. However, the electrolyte containing 100% Hex4N(+)I(-) and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex4N(+)I(-) and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm(-2) short circuit current density. PMID:22618351

  10. Recent patents on imaging nanoprobes for brain tumor diagnosis and therapy.

    PubMed

    Qi, Lifeng; Zheng, Shu; Lin, Biaoyang

    2010-06-01

    Multifunctional nanoprobes, such as nanocrystals, nanoshells, and luminescent nanomaterials, have been developed for imaging biological processes; such as cell signaling, neuroimaging, protein conformation probing, DNA conformation probing, gene transcription, virus infection and replication in cells, protein dynamics, tumor diagnosis, and therapy evaluation. With the application of nanotechnology for CNS-active agents' delivery, nanostructured materials are emerging as a powerful means for diagnosis of CNS disorders, including brain tumors, because of their unique optical size, and surface properties. This review summarizes the recent patents on imaging nanoprobes for brain tumor diagnosis and therapy. The future development in this active cross-disciplinary field will be discussed as well. PMID:20156135

  11. Binary Plutinos

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    2015-08-01

    The Pluto-Charon binary was the first trans-neptunian binary to be identified in 1978. Pluto-Charon is a true binary with both components orbiting a barycenter located between them. The Pluto system is also the first, and to date only, known binary with a satellite system consisting of four small satellites in near-resonant orbits around the common center of mass. Seven other Plutinos, objects in 3:2 mean motion resonance with Neptune, have orbital companions including 2004 KB19 reported here for the first time. Compared to the Cold Classical population, the Plutinos differ in the frequency of binaries, the relative sizes of the components, and their inclination distribution. These differences point to distinct dynamical histories and binary formation processes encountered by Plutinos.

  12. Magnetic Force Nanoprobe for Direct Observation of Audio Frequency Tonotopy of Hair Cells.

    PubMed

    Kim, Ji-Wook; Lee, Jae-Hyun; Ma, Ji-Hyun; Chung, Eunna; Choi, Hongsuh; Bok, Jinwoong; Cheon, Jinwoo

    2016-06-01

    Sound perception via mechano-sensation is a remarkably sensitive and fast transmission process, converting sound as a mechanical input to neural signals in a living organism. Although knowledge of auditory hair cell functions has advanced over the past decades, challenges remain in understanding their biomechanics, partly because of their biophysical complexity and the lack of appropriate probing tools. Most current studies of hair cells have been conducted in a relatively low-frequency range (<1000 Hz); therefore, fast kinetic study of hair cells has been difficult, even though mammalians have sound perception of 20 kHz or higher. Here, we demonstrate that the magnetic force nanoprobe (MFN) has superb spatiotemporal capabilities to mechanically stimulate spatially-targeted individual hair cells with a temporal resolution of up to 9 μs, which is equivalent to approximately 50 kHz; therefore, it is possible to investigate avian hair cell biomechanics at different tonotopic regions of the cochlea covering a full hearing frequency range of 50 to 5000 Hz. We found that the variation of the stimulation frequency and amplitude of hair bundles creates distinct mechanical responsive features along the tonotopic axis, where the kinetics of the hair bundle recovery motion exhibits unique frequency-dependent characteristics: basal, middle, and apical hair bundles can effectively respond at their respective ranges of frequency. We revealed that such recovery kinetics possesses two different time constants that are closely related to the passive and active motilities of hair cells. The use of MFN is critical for the kinetics study of free-standing hair cells in a spatiotemporally distinct tonotopic organization. PMID:27215487

  13. Efficient Two-Photon Fluorescence Nanoprobe for Turn-On Detection and Imaging of Ascorbic Acid in Living Cells and Tissues.

    PubMed

    Meng, Hong-Min; Zhang, Xiao-Bing; Yang, Chan; Kuai, Hailan; Mao, Guo-Jiang; Gong, Liang; Zhang, Wenhan; Feng, Suling; Chang, Junbiao

    2016-06-01

    Ascorbic acid (AA) serves as a key coenzyme in many metabolic pathways, and its abnormal level is found to be associated with several diseases. Therefore, monitoring AA level in living systems is of great biomedical significance. In comparison with one-photon excited fluorescent probes, two-photon (TP) excited probes are more suitable for bioimaging, as they could afford higher imaging resolution with deeper imaging depth. Here, we report for the first time an efficient TP fluorescence probe for turn-on detection and imaging of AA in living cells and tissues. In this nanosystem, the negatively charged two-photon nanoparticles (TPNPs), which were prepared by modifying the silica nanoparticles with a two-photon dye, could adsorb cobalt oxyhydroxide (CoOOH) nanoflakes which carried positive charge by electrostatic force, leading to a remarkable decrease in their fluorescence intensity. However, the introduction of AA could induce the fluorescence recovery of the nanoprobe because it could reduce CoOOH into Co(2+) and result in the destruction of the CoOOH nanoflakes. The nanosystem exhibits a high sensitivity toward AA, with a LOD of 170 nM observed. It also shows high selectivity toward AA over common potential interfering species. The nanoprobe possessed both the advantages of TP imaging and excellent membrane-permeability and good biocompatibility of the silica nanoparticles and was successfully applied in TP-excited imaging of AA in living cells and tissues. PMID:27161421

  14. Performance characteristics of guanine incorporated PVDF-HFP/PEO polymer blend electrolytes with binary iodide salts for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Senthil, R. A.; Theerthagiri, J.; Madhavan, J.; Arof, A. K.

    2016-08-01

    In this work, we have investigated the influence of guanine as an organic dopant in dye-sensitized solar cell (DSSC) based on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) polymer blend electrolyte along with binary iodide salts (potassium iodide (KI) and tetrabutylammonium iodide (TBAI)) and iodine (I2). The PVDF-HFP/KI + TBAI/I2, PVDF-HFP/PEO/KI + TBAI/I2 and guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolytes were prepared by solution casting technique using DMF as solvent. The PVDF-HFP/KI + TBAI/I2 electrolyte showed an ionic conductivity value of 9.99 × 10-5 Scm-1, whereas, it was found to be increased to 4.53 × 10-5 Scm-1 when PEO was blended with PVDF-HFP/KI + TBAI/I2 electrolyte. However, a maximum ionic conductivity value of 3.67 × 10-4 Scm-1 was obtained for guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 blend electrolyte. The photovoltaic properties of all these polymer electrolytes in DSSCs were characterized. As a consequence, the power conversion efficiency of the guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC was significantly improved to 4.98% compared with PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC (2.46%). These results revealed that the guanine can be an effective organic dopant to enhance the performance of DSSCs.

  15. Fluorescent and bioluminescent nanoprobes for in vitro and in vivo detection of matrix metalloproteinase activity

    PubMed Central

    Lee, Hawon; Kim, Young-Pil

    2015-01-01

    Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade the extracellular matrix (ECM) and regulate the extracellular microenvironment. Despite the significant role that MMP activity plays in cell-cell and cell-ECM interactions, migration, and differentiation, analyses of MMPs in vitro and in vivo have relied upon their abundance using conventional immunoassays, rather than their enzymatic activities. To resolve this issue, diverse nanoprobes have emerged and proven useful as effective activity-based detection tools. Here, we review the recent advances in luminescent nanoprobes and their applications in in vitro diagnosis and in vivo imaging of MMP activity. Nanoprobes with the purpose of sensing MMP activity consist of recognition and detection units, which include MMP-specific substrates and luminescent (fluorescent or bioluminescent) nanoparticles, respectively. With further research into improvement of the optical performance, it is anticipated that luminescent nanoprobes will have great potential for the study of the functional roles of proteases in cancer biology and nanomedicine. [BMB Reports 2015; 48(6): 313-318] PMID:25817215

  16. Investigation of apoptotic events at molecular level induced by SERS guided targeted theranostic nanoprobe.

    PubMed

    Narayanan, Nisha; Nair, Lakshmi V; Karunakaran, Varsha; Joseph, Manu M; Nair, Jyothi B; N, Ramya A; Jayasree, Ramapurath S; Maiti, Kaustabh Kumar

    2016-06-01

    Herein, we have examined distinctive structural and functional variations of cellular components during apoptotic cell death induced by a targeted theranostic nanoprobe, MMP-SQ@GNR@LAH-DOX, which acted as a SERS "on/off" probe in the presence of a MMP protease and executed synergistic photothermal chemotherapy, as reflected by the SERS fingerprinting, corresponding to the phosphodiester backbone of DNA. PMID:27211810

  17. A robot-based detector manipulator system for a hard x-ray nanoprobe instrument.

    SciTech Connect

    Shu, D., Maser, J., Holt, M. , Winarski, R., Preissner, C.,Lai, B., Vogt, S., Stephenson, G.B.

    2007-11-11

    This paper presents the design of a robot-based detector manipulator for microdiffraction applications with a hard X-ray nanoprobe instrument system being constructed at the Advanced Photon Source (APS) for the Center for Nanoscale Materials (CNM) being constructed at Argonne National Laboratory (ANL). Applications for detectors weighing from 1.5 to 100 kg were discussed in three configurations.

  18. Multifunctional nanoprobe for cancer cell targeting and simultaneous fluorescence/magnetic resonance imaging.

    PubMed

    Wei, Zhenzhen; Wu, Yafeng; Zhao, Yuewu; Mi, Li; Wang, Jintao; Wang, Jimin; Zhao, Jinjin; Wang, Lixin; Liu, Anran; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2016-09-28

    Multifunctional nanoprobes with distinctive magnetic and fluorescent properties are highly useful in accurate and early cancer diagnosis. In this study, nanoparticles of Fe3O4 core with fluorescent SiO2 shell (MFS) are synthesized by a facile improved Stöber method. These nanoparticles owning a significant core-shell structure exhibit good dispersion, stable fluorescence, low cytotoxicity and excellent biocompatibility. TLS11a aptamer (Apt1), a specific membrane protein for human liver cancer cells which could be internalized into cells, is conjugated to the MFS nanoparticles through the formation of amide bond working as a target-specific moiety. The attached TLS11a aptamers on nanoparticles are very stable and can't be hydrolyzed by DNA hydrolytic enzyme in vivo. Both fluorescence and magnetic resonance imaging show significant uptake of aptamer conjugated nanoprobe by HepG2 cells compared to 4T1, SGC-7901 and MCF-7 cells. In addition, with the increasing concentration of the nanoprobe, T2-weighted MRI images of the as-treated HepG2 cells are significantly negatively enhanced, indicating that a high magnetic field gradient is generated by MFS-Apt1 which has been specifically captured by HepG2 cells. The relaxivity of nanoprobe is calculated to be 11.5 mg(-1)s(-1). The MR imaging of tumor-bearing nude mouse is also confirmed. The proposed multifunctional nanoprobe with the size of sub-100 nm has the potential to provide real-time imaging in early liver cancer cell diagnosis. PMID:27619098

  19. Binary stars.

    PubMed

    Paczynacuteski, B

    1984-07-20

    Most stars in the solar neighborhood are either double or multiple systems. They provide a unique opportunity to measure stellar masses and radii and to study many interesting and important phenomena. The best candidates for black holes are compact massive components of two x-ray binaries: Cygnus X-1 and LMC X-3. The binary radio pulsar PSR 1913 + 16 provides the best available evidence for gravitational radiation. Accretion disks and jets observed in close binaries offer a very good testing ground for models of active galactic nuclei and quasars. PMID:17749544

  20. A multifunctional mesoporous Fe3O4/SiO2/CdTe magnetic-fluorescent composite nanoprobe

    NASA Astrophysics Data System (ADS)

    Yin, Naiqiang; Wu, Ping; Liang, Guo; Cheng, Wenjing

    2016-03-01

    A multifunctional mesoporous, magnetic and fluorescent Fe3O4/SiO2/CdTe nanoprobe with well-defined core-shell nanostructures was prepared. This multifunctional nanoprobe was synthesized through a novel method mainly including two steps. The first step involved the controlled growth of mesoporous silica layer onto the surface of Fe3O4 nanoparticle using tetraethyl orthosilicate as silica source, cationic surfactant cetyltrimethylammonium bromide as template, and 1,3,5-triisopropylbenzene as pore swelling agents. The second step involved the layer-by-layer assembly of 3-aminopropyltrimethoxysilane and fluorescent CdTe quantum dots with the mesoporous Fe3O4/SiO2 nanoparticles. The well-designed nanoprobe exhibits strong excitonic photoluminescence and superparamagnetism at room temperature. In attention, the mesoporous silica layer of the nanoprobe with great loading capacity makes it a promising candidate as targeted drug delivery platform.

  1. A NaYbF4: Tm3+ nanoprobe for CT and NIR-to-NIR fluorescent bimodal imaging.

    PubMed

    Xing, Huaiyong; Bu, Wenbo; Ren, Qingguo; Zheng, Xiangpeng; Li, Ming; Zhang, Shengjian; Qu, Haiyun; Wang, Zheng; Hua, Yanqing; Zhao, Kuaile; Zhou, Liangping; Peng, Weijun; Shi, Jianlin

    2012-07-01

    Early diagnosis that combines the high-resolutional CT and sensitive NIR-fluorescence bioimaging could provide more accurate information for cancerous tissues, which, however, remain a big challenge. Here we report a simple bimodal imaging platform based on PEGylated NaYbF(4): Tm(3+) nanoparticles (NPs) of less than 20 nm in diameter for both CT and NIR-fluorescence bioimaging. The as-designed nanoprobes showed excellent in vitro and in vivo performances in the dual-bioimaging, very low cytotoxicity and no detectable tissue damage in one month. Remarkably, the Yb(3+) in the lattice of NaYbF(4): Tm(3+) NPs functions not only as a promising CT contrast medium due to its high X-ray absorption coefficiency, but also an excellent sensitizer contributing to the strong NIR-fluorescent emissions for its large NIR absorption cross-section. In addition, these NPs could be easily excreted mainly via feces without detectable remnant in the animal bodies. PMID:22538199

  2. A New Polymer Nanoprobe Based on Chemiluminescence Resonance Energy Transfer for Ultrasensitive Imaging of Intrinsic Superoxide Anion in Mice.

    PubMed

    Li, Ping; Liu, Lu; Xiao, Haibin; Zhang, Wei; Wang, Lulin; Tang, Bo

    2016-03-01

    Despite significant developments in optical imaging of superoxide anion (O2(•-)) as the preliminary reactive oxygen species, novel visualizing strategies that offer ultrahigh sensitivity are still imperative. This is mainly because intrinsic concentrations of O2(•-) are extremely low in living systems. Herein, we present the rational design and construction of a new polymer nanoprobe PCLA-O2(•-) for detecting O2(•-) based on chemiluminescence (CL) resonance energy transfer without an external excitation source. Structurally, PCLA-O2(•-) contains two moieties linked covalently, namely imidazopyrazinone that is capable of CL triggered by O2(•-) as the energy donor and conjugated polymers with light-amplifying property as the energy acceptor. Experiment results demonstrate that PCLA-O2(•-) exhibits ultrahigh sensitivity at the picomole level, dramatically prolonged luminescence time, specificity, and excellent biocompatibility. Without exogenous stimulation, this probe for the first time in situ visualizes O2(•-) level differences between normal and tumor tissues of mice. These exceptional features ensure that PCLA-O2(•-) as a self-luminescing probe is an alternative in vivo imaging approach for ultralow level O2(•-). PMID:26908223

  3. Nanobiophotonics for molecular imaging of cancer: Au- and Ag-based Epidermal Growth Factor receptor (EGFR) specific nanoprobes

    NASA Astrophysics Data System (ADS)

    Lucas, Leanne J.; Hewitt, Kevin C.

    2012-03-01

    Our aim is to create and validate a novel SERS-based nanoprobe for optical imaging of the epidermal growth factor receptor (EGFR). Gold and silver nanoparticles (Au/AgNPs) of various sizes were synthesized and coupled to epidermal growth factor (EGF) via a short ligand, α-lipoic acid (206 g/mol), which binds strongly to both Au and Ag nanoparticles via its disulfide end group. We used carbodiimide chemistry to couple EGF to α-lipoic acid. These nanoprobes were tested for binding affinity using Enzyme Linked ImmunoSorbent Assay (ELISA) and, in-vitro, using EGFRoverexpressing A431 cells. The nanoprobes show excellent EGFR-specific binding. Time of Flight Mass Spectrometry demonstrate the carbodiimide based linking of the carboxylic acid end-group of α-lipoic acid to one or more of the three (terminal, or 2 lysine) amine groups on EGF. ELISA confirms that the linked EGF is active by itself, and following conjugation with gold or silver nanoparticles. Compared with bare nanoparticles, UV-Vis spectroscopy of Ag-based nanoprobes exhibit significant plasmon red-shift, while there was no discernable shift for Au-based ones. Dark field microscopy shows abundant uptake by EGFR overexpressing A431 cells, and serves to further confirm the excellent binding affinity. Nanoprobe internalization and consequent aggregation is thought to be the basis of enhanced light scattering in the dark field images, supporting the notion that these nanoprobes should provide excellent SERS signals at all nanoprobe sizes. In summary, novel EGFR-specific nanoprobes have been synthesized and validated by standard assay and in cell culture for use as SERS optical imaging probes.

  4. Real-time detection of implant-associated neutrophil responses using a formyl peptide receptor-targeting NIR nanoprobe

    PubMed Central

    Zhou, Jun; Tsai, Yi-Ting; Weng, Hong; Tang, Ewin N; Nair, Ashwin; Davé, Digant P; Tang, Liping

    2012-01-01

    Neutrophils play an important role in implant-mediated inflammation and infection. Unfortunately, current methods which monitor neutrophil activity, including enzyme measurements and histological evaluation, require many animals and cannot be used to accurately depict the dynamic cellular responses. To understand the neutrophil interactions around implant-mediated inflammation and infection it is critical to develop methods which can monitor in vivo cellular activity in real time. In this study, formyl peptide receptor (FPR)-targeting near-infrared nanoprobes were fabricated. This was accomplished by conjugating near-infrared dye with specific peptides having a high affinity to the FPRs present on activated neutrophils. The ability of FPR-targeting nanoprobes to detect and quantify activated neutrophils was assessed both in vitro and in vivo. As expected, FPR-targeting nanoprobes preferentially accumulated on activated neutrophils in vitro. Following transplantation, FPR-targeting nanoprobes preferentially accumulated at the biomaterial implantation site. Equally important, a strong relationship was observed between the extent of fluorescence intensity in vivo and the number of recruited neutrophils at the implantation site. Furthermore, FPR-targeting nanoprobes may be used to detect and quantify the number of neutrophils responding to a catheter-associated infection. The results show that FPR-targeting nanoprobes may serve as a powerful tool to monitor and measure the extent of neutrophil responses to biomaterial implants in vivo. PMID:22619542

  5. Moving graphene devices from lab to market: advanced graphene-coated nanoprobes

    NASA Astrophysics Data System (ADS)

    Hui, Fei; Vajha, Pujashree; Shi, Yuanyuan; Ji, Yanfeng; Duan, Huiling; Padovani, Andrea; Larcher, Luca; Li, Xiao Rong; Xu, Jing Juan; Lanza, Mario

    2016-04-01

    After more than a decade working with graphene there is still a preoccupying lack of commercial devices based on this wonder material. Here we report the use of high-quality solution-processed graphene sheets to fabricate ultra-sharp probes with superior performance. Nanoprobes are versatile tools used in many fields of science, but they can wear fast after some experiments, reducing the quality and increasing the cost of the research. As the market of nanoprobes is huge, providing a solution for this problem should be a priority for the nanotechnology industry. Our graphene-coated nanoprobes not only show enhanced lifetime, but also additional unique properties of graphene, such as hydrophobicity. Moreover, we have functionalized the surface of graphene to provide piezoelectric capability, and have fabricated a nano relay. The simplicity and low cost of this method, which can be used to coat any kind of sharp tip, make it suitable for the industry, allowing production on demand.After more than a decade working with graphene there is still a preoccupying lack of commercial devices based on this wonder material. Here we report the use of high-quality solution-processed graphene sheets to fabricate ultra-sharp probes with superior performance. Nanoprobes are versatile tools used in many fields of science, but they can wear fast after some experiments, reducing the quality and increasing the cost of the research. As the market of nanoprobes is huge, providing a solution for this problem should be a priority for the nanotechnology industry. Our graphene-coated nanoprobes not only show enhanced lifetime, but also additional unique properties of graphene, such as hydrophobicity. Moreover, we have functionalized the surface of graphene to provide piezoelectric capability, and have fabricated a nano relay. The simplicity and low cost of this method, which can be used to coat any kind of sharp tip, make it suitable for the industry, allowing production on demand. Electronic

  6. Tunable and amplified Raman gold nanoprobes for effective tracking (TARGET): in vivo sensing and imaging

    NASA Astrophysics Data System (ADS)

    Gandra, Naveen; Hendargo, Hansford C.; Norton, Stephen J.; Fales, Andrew M.; Palmer, Gregory M.; Vo-Dinh, Tuan

    2016-04-01

    We describe the development of a highly tunable, physiologically stable, and ultra-bright Raman probe, named as TARGET (Tunable and Amplified Raman Gold Nanoprobes for Effective Tracking), for in vitro and in vivo surface-enhanced Raman scattering (SERS) applications. The TARGET structure consists of a gold core inside a larger gold shell with a tunable interstitial gap similar to a ``nanorattle'' structure. The combination of galvanic replacement and the seed mediated growth method was employed to load Raman reporter molecules and subsequently close the pores to prevent leaking and degradation of reporters under physiologically extreme conditions. Precise tuning of the core-shell gap width, core size, and shell thickness allows us to modulate the plasmonic effect and achieve a maximum electric-field (E-field) intensity. The interstitial gap of TARGET nanoprobes can be designed to exhibit a plasmon absorption band at 785 nm, which is in resonance with the dye absorption maximum and lies in the ``tissue optical window'', resulting in ultra-bright SERS signals for in vivo studies. The results of in vivo measurements of TARGETs in laboratory mice illustrated the usefulness of these nanoprobes for medical sensing and imaging.We describe the development of a highly tunable, physiologically stable, and ultra-bright Raman probe, named as TARGET (Tunable and Amplified Raman Gold Nanoprobes for Effective Tracking), for in vitro and in vivo surface-enhanced Raman scattering (SERS) applications. The TARGET structure consists of a gold core inside a larger gold shell with a tunable interstitial gap similar to a ``nanorattle'' structure. The combination of galvanic replacement and the seed mediated growth method was employed to load Raman reporter molecules and subsequently close the pores to prevent leaking and degradation of reporters under physiologically extreme conditions. Precise tuning of the core-shell gap width, core size, and shell thickness allows us to modulate the

  7. Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Pravec, P.

    2006-06-01

    There are now nearly 100 binary asteroids known. In the last year alone, 30 binary asteroids have been discovered, half of them by lightcurves showing eclipse events. Similar to eclipsing binary stars, such observations allow determination of orbit period and sizes and shapes of the primary and secondary relative to the orbital dimension. From these parameters one can estimate the mean density of the system, and a number of dynamical properties such as total specific angular momentum, tidal evolution time scales of spins and orbit, and precession frequencies of the orbit about the primary and of the solar induced "general precession" of the system. We have extracted parameters for all systems with enough observations to allow meaningful determinations. Some preliminary results include: (1) Binaries are roughly as prevalent among small main-belt asteroids as among Near-Earth Asteroids. (2) Most binaries are partially asynchronous, with the secondary synchronized to the orbit period, but the primary still spinning much faster. This is consistent with estimated tidal damping time scales. (3) Most systems have near the critical maximum angular momentum for a single "rubble pile" body, but not much more, and some less. Thus fission appears not to be a viable formation mechanism for all binaries, although near-critical spin rate seems to play a role. (4) Orbits of the secondaries are essentially in the equatorial plane of the primary. Since most primary spins are still fast, the satellites must have been formed into low inclination orbits. (5) Precession frequencies are in the range of the shorter resonance frequencies in the solar system (tens of thousands of years), thus resonance interactions can be expected to have altered spin orientations as systems evolved slowly by tidal friction or other processes. (6) Primaries are unusually spheroidal, which is probably necessary for stability of the binary once formed.

  8. NIR-to-NIR two-photon excited CaF2:Tm3+,Yb3+ nanoparticles: multifunctional nanoprobes for highly penetrating fluorescence bio-imaging.

    PubMed

    Dong, Ning-Ning; Pedroni, Marco; Piccinelli, Fabio; Conti, Giamaica; Sbarbati, Andrea; Ramírez-Hernández, Juan Enrique; Maestro, Laura Martínez; Iglesias-de la Cruz, Maria Carmen; Sanz-Rodriguez, Francisco; Juarranz, Angeles; Chen, Feng; Vetrone, Fiorenzo; Capobianco, John A; Solé, José García; Bettinelli, Marco; Jaque, Daniel; Speghini, Adolfo

    2011-11-22

    In this study, we report on the remarkable two-photon excited fluorescence efficiency in the "biological window" of CaF(2):Tm(3+),Yb(3+) nanoparticles. On the basis of the strong Tm(3+) ion emission (at around 800 nm), tissue penetration depths as large as 2 mm have been demonstrated, which are more than 4 times those achievable based on the visible emissions in comparable CaF(2):Er(3+),Yb(3+) nanoparticles. The outstanding penetration depth, together with the fluorescence thermal sensitivity demonstrated here, makes CaF(2):Tm(3+),Yb(3+) nanoparticles ideal candidates as multifunctional nanoprobes for high contrast and highly penetrating in vivo fluorescence imaging applications. PMID:21957870

  9. Investigation of apoptotic events at molecular level induced by SERS guided targeted theranostic nanoprobe

    NASA Astrophysics Data System (ADS)

    Narayanan, Nisha; Nair, Lakshmi V.; Karunakaran, Varsha; Joseph, Manu M.; Nair, Jyothi B.; N, Ramya A.; Jayasree, Ramapurath S.; Maiti, Kaustabh Kumar

    2016-06-01

    Herein, we have examined distinctive structural and functional variations of cellular components during apoptotic cell death induced by a targeted theranostic nanoprobe, MMP-SQ@GNR@LAH-DOX, which acted as a SERS ``on/off'' probe in the presence of a MMP protease and executed synergistic photothermal chemotherapy, as reflected by the SERS fingerprinting, corresponding to the phosphodiester backbone of DNA.Herein, we have examined distinctive structural and functional variations of cellular components during apoptotic cell death induced by a targeted theranostic nanoprobe, MMP-SQ@GNR@LAH-DOX, which acted as a SERS ``on/off'' probe in the presence of a MMP protease and executed synergistic photothermal chemotherapy, as reflected by the SERS fingerprinting, corresponding to the phosphodiester backbone of DNA. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03385g

  10. Investigations of electrical transport properties of individual carbon nanotubes with nanoprober

    NASA Astrophysics Data System (ADS)

    Feng, Wei; Hayama, Kazumi; Akinaga, Hiroyuki

    2016-06-01

    We investigated and discussed quantitatively the transport properties of individual multiwalled (MW) carbon nanotubes (CNTs) by four-terminal measurement using a nanoprobing system. The homogeneity of the CNT was visibly examined using the electron beam absorbed current function of the nanoprober. The observed ohmic properties of the current–voltage characteristics and metallic transport properties of the CNTs proved that reliable contact of four probes was achieved on the outermost shell of MWCNTs. The experimental methodology was validated for the intrinsic properties of individual CNTs. Lower resistance per unit length was evaluated for thicker CNT. The measured resistance per unit length was lower than those reported by other researchers, but higher than ideally expected.

  11. Three-Dimensional Rapid Prototyping of Multidirectional Polymer Nanoprobes for Single Cell Insertion.

    PubMed

    Yang, Dasom; Hong, Hyeonaug; Seo, Yoon Ho; Kim, Lo Hyun; Ryu, WonHyoung

    2015-08-01

    Three-dimensional (3D) thermal drawing at nanoscale as a novel rapid prototyping method was demonstrated to create multidirectional polymer nanoprobes for single cell analysis. This 3D drawing enables simple and rapid fabrication of polymeric nanostructures with high aspect ratio. The effect of thermal drawing parameters, such as drawing speeds, dipping depths, and contact duration on the final geometry of polymer nanostructures was investigated. Vertically aligned and L-shaped nanoprobes were fabricated and their insertion into living single cells such as algal cells and human neural stem cells was demonstrated. This technique can be extended to create more complex 3D structures by controlling drawing steps and directions on any surface. PMID:26144221

  12. Label-Free Carbon-Dots-Based Ratiometric Fluorescence pH Nanoprobes for Intracellular pH Sensing.

    PubMed

    Shangguan, Jingfang; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Liu, Jinquan; Tang, Jinlu; Yang, Xue; Huang, Jin

    2016-08-01

    Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels. PMID:27334762

  13. Targeted Near-Infrared Fluorescent Turn-on Nanoprobe for Activatable Imaging and Effective Phototherapy of Cancer Cells.

    PubMed

    Li, Na; Li, Tingting; Hu, Chao; Lei, Xiaomin; Zuo, Yunpeng; Han, Heyou

    2016-06-22

    A novel and green multifunctional nanoplatform as a nanocarrier for drug delivery, cell imaging, and phototherapy has been engineered. The nanoplatform is composed of stabilized carbon spheres (CSs) as cores, a coated polydopamine (PDA) shell, targeted folic acid (FA), and the loaded anticancer drug indocyanine green (ICG), obtaining CSs@PDA-FA@ICG nanocomposites (NCs). The biocompatible PDA shell provided a high fluorescence quenching efficiency and a surface rich in functional groups for anchoring FA for targeting cancer cells. Aromatic ICG could be effectively loaded into the CSs@PDA-FA system via hydrophobic interactions and π-π stacking with a loading efficiency of 58.9%. Notably, the activated NIR fluorescence in an intracellular environment made CSs@PDA-FA@ICG a sensitive "OFF" to "ON" nanoprobe that can be used for NIR imaging. Moreover, compared to ICG alone, the CSs@PDA-FA@ICG NCs could induce efficient photoconversion for simultaneous synergetic photodynamic therapy (PDT) and photothermal therapy (PTT) under a single NIR laser irradiation. The results demonstrated that CSs@PDA-FA@ICG NCs as a targeted and activated nanoplatform provide new opportunities to facilitate the accurate diagnosis of cancer and enhanced treatment efficacy. This work stimulates more interest in the design of the facile surface functionalization strategy to construct other multifunctional nanocomposites, such as nanotubes and nanorods. PMID:25996034

  14. Smart nanoprobes for the detection of alkaline phosphatase activity during osteoblast differentiation.

    PubMed

    Lim, Eun-Kyung; Keem, Joo Oak; Yun, Hui-suk; Jung, Jinyoung; Chung, Bong Hyun

    2015-02-21

    Gold nanoparticle-conjugated fluorescent hydroxyapatite (AuFHAp) was developed as a smart nanoprobe for measuring alkaline phosphatase (ALP) activity. AuFHAp showed NIR fluorescence due to the hydrolysis of its phosphate groups by ALP. In addition, gold nanoparticles help reduce the nonspecific signal by absorbing nonspecific fluorescence. Through in vitro tests, we confirmed that the AuFHAp probe was capable of detecting ALP levels related to osteoblast activity in living cells with high fluorescence intensity. PMID:25623488

  15. Photoacoustic and Fluorescence Image-Guided Surgery Using a Multifunctional Targeted Nanoprobe

    PubMed Central

    Xi, Lei; Zhou, Guangyin; Gao, Ning; Yang, Lily; Gonzalo, David A.; Hughes, Steven J.; Jiang, Huabei

    2016-01-01

    Purpose A complete surgical excision with negative tumor margins is the single most important factor in the prediction of long-term survival for most cancer patients with solid tumors. We hypothesized that image-guided surgery using nanoparticle-enhanced photoacoustic and fluorescence imaging could significantly reduce the rate of local recurrence. Methods A murine model of invasive mammary carcinoma was utilized. Three experimental groups were included: (1) control; (2) tumor-bearing mice injected with non-targeted nanoprobe; and (3) tumor-bearing mice injected with targeted nanoprobe. The surgeon removed the primary tumor following the guidance of photoacoustic imaging (PAI), then inspected the surgical wound and removed the suspicious tissue using intraoperative near-infrared (NIR) fluorescence imaging. The mice were followed with bioluminescence imaging weekly to quantify local recurrence. Results Nanoprobe-enhanced photoacoustic contrast enabled PAI to map the volumetric tumor margins up to a depth of 31 mm. The targeted nanoparticles provided significantly greater enhancement than non-targeted nano-particles. Seven mice in the group injected with the targeted nanoprobes underwent additional resections based upon NIR fluorescence imaging. Pathological analysis confirmed residual cancer cells in the re-resected specimens in 5/7 mice. Image-guided resection resulted in a significant reduction in local recurrence; 8.7 and 33.3 % of the mice in the targeted and control groups suffered recurrence, respectively. Conclusions These results suggest that photoacoustic and NIR intraoperative imaging can effectively assist a surgeon to locate primary tumors and to identify residual disease in real-time. This technology has promise to overcome current clinical challenges that result in the need for second surgical procedures. PMID:24554061

  16. Tunable and amplified Raman gold nanoprobes for effective tracking (TARGET): in vivo sensing and imaging.

    PubMed

    Gandra, Naveen; Hendargo, Hansford C; Norton, Stephen J; Fales, Andrew M; Palmer, Gregory M; Vo-Dinh, Tuan

    2016-04-28

    We describe the development of a highly tunable, physiologically stable, and ultra-bright Raman probe, named as TARGET (Tunable and Amplified Raman Gold Nanoprobes for Effective Tracking), for in vitro and in vivo surface-enhanced Raman scattering (SERS) applications. The TARGET structure consists of a gold core inside a larger gold shell with a tunable interstitial gap similar to a "nanorattle" structure. The combination of galvanic replacement and the seed mediated growth method was employed to load Raman reporter molecules and subsequently close the pores to prevent leaking and degradation of reporters under physiologically extreme conditions. Precise tuning of the core-shell gap width, core size, and shell thickness allows us to modulate the plasmonic effect and achieve a maximum electric-field (E-field) intensity. The interstitial gap of TARGET nanoprobes can be designed to exhibit a plasmon absorption band at 785 nm, which is in resonance with the dye absorption maximum and lies in the "tissue optical window", resulting in ultra-bright SERS signals for in vivo studies. The results of in vivo measurements of TARGETs in laboratory mice illustrated the usefulness of these nanoprobes for medical sensing and imaging. PMID:27064259

  17. A choline derivate-modified nanoprobe for glioma diagnosis using MRI

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Huang, Shixian; Shao, Kun; Liu, Yang; An, Sai; Kuang, Yuyang; Guo, Yubo; Ma, Haojun; Wang, Xuxia; Jiang, Chen

    2013-04-01

    Gadolinium (Gd) chelate contrast-enhanced magnetic resonance imaging (MRI) is a preferred method of glioma detection and preoperative localisation because it offers high spatial resolution and non-invasive deep tissue penetration. Gd-based contrast agents, such as Gd-diethyltriaminepentaacetic acid (DTPA-Gd, Magnevist), are widely used clinically for tumor diagnosis. However, the Gd-based MRI approach is limited for patients with glioma who have an uncompromised blood-brain barrier (BBB). Moreover, the rapid renal clearance and non-specificity of such contrast agents further hinders their prevalence. We present a choline derivate (CD)-modified nanoprobe with BBB permeability, glioma specificity and a long blood half-life. Specific accumulation of the nanoprobe in gliomas and subsequent MRI contrast enhancement are demonstrated in vitro in U87 MG cells and in vivo in a xenograft nude model. BBB and glioma dual targeting by this nanoprobe may facilitate precise detection of gliomas with an uncompromised BBB and may offer better preoperative and intraoperative tumor localization.

  18. Au-nanoprobes for detection of SNPs associated with antibiotic resistance in Mycobacterium tuberculosis

    NASA Astrophysics Data System (ADS)

    Veigas, Bruno; Machado, Diana; Perdigão, João; Portugal, Isabel; Couto, Isabel; Viveiros, Miguel; Baptista, Pedro V.

    2010-10-01

    Tuberculosis (TB) is one of the leading causes of infection in humans, causing high morbility and mortality all over the world. The rate of new cases of multidrug resistant tuberculosis (MDRTB) continues to increase, and since these infections are very difficult to manage, they constitute a serious health problem. In most cases, drug resistance in Mycobacterium tuberculosis has been related to mutations in several loci within the pathogen's genome. The development of fast, cheap and simple screening methodologies would be of paramount relevance for the early detection of these mutations, essential for the timely and effective diagnosis and management of MDRTB patients. The use of gold nanoparticles derivatized with thiol-modified oligonucleotides (Au-nanoprobes) has led to new approaches in molecular diagnostics. Based on the differential non-cross-linking aggregation of Au-nanoprobes, we were able to develop a colorimetric method for the detection of specific sequences and to apply this approach to pathogen identification and single base mutations/single nucleotide polymorphisms (SNP) discrimination. Here we report on the development of Au-nanoprobes for the specific identification of SNPs within the beta subunit of the RNA polymerase (rpoB locus), responsible for resistance to rifampicin in over 95% of rifampicin resistant M. tuberculosis strains.

  19. Tracking SERS-active nanoprobe intracellular uptake for chemical and biological sensing

    NASA Astrophysics Data System (ADS)

    Gregas, Molly K.; Yan, Fei; Scaffidi, Jonathan; Wang, Hsin-Neng; Khoury, Christopher; Zhang, Yan; Vo-Dinh, Tuan

    2007-09-01

    A critical aspect of the use of nanoprobes for intracellular studies in chemical and biological sensing involves a fundamental understanding of their uptake and trajectory in cells. In this study, we describe experiments using surface-enhanced Raman scattering (SERS) spectroscopy and mapping to track cellular uptake of plasmonics-active labeled nanoparticles. Three different Raman-active labels with positive, negative, and neutral charges were conjugated to silver colloidal nanoparticles with the aim of spatially and temporally profiling intracellular delivery and tracking of nanoprobes during uptake in single mammalian cells. 1-D Raman spectra and 2-D Raman mapping are used to identify and locate the probes via their SERS signal intensities. Because Raman spectroscopy is very specific for identification of chemical and molecular signatures, the development of functionalized plasmonics-active nanoprobes capable of exploring intracellular spaces and processes has the ability to provide specific information on the effects of biological and chemical pollutants in the intracellular environment. The results indicate that this technique will allow study of when, where, and how these substances affect cells and living organisms.

  20. Epidermal Growth Factor Receptor-Specific Nanoprobe Biodistribution in Mouse Models.

    PubMed

    Lee, Christopher L D; Fashir, Samia B; Castilho, Maiara L; Hupman, Michael A; Raniero, Leandro J; Alwayn, Ian; Hewitt, Kevin C

    2016-01-01

    Nanotechnology offers a targeted approach to both imaging and treatment of cancer, the leading cause of death worldwide. Previous studies have found that nanoparticles with a wide variety of coatings initiate an immune response leading to sequestration in the liver and spleen. In an effort to find a nanoparticle platform which does not elicit an immune response, we created 43 nm and 44 nm of gold and silver nanoparticles coated with biomolecules normally produced by the body, α-lipoic acid and the epidermal growth factor (EGF), and have used mass spectroscopy to determine their biodistribution in mouse models, 24 h after tail vein injection. Relative to controls, mouse EGF (mEGF)-coated silver and gold nanoprobes are found at background levels in all organs including the liver and spleen. The lack of sequestration of mEGF-coated nanoprobes in the liver and spleen and the corresponding uptake of control nanoprobes at elevated levels in these organs suggest that the former are not recognized by the immune system. Further studies of cytokine and interleukin levels in the blood are required to confirm avoidance of an immune response. PMID:26852838

  1. New binary systems: beaming binaries

    NASA Astrophysics Data System (ADS)

    Morales, J. C.; Weingrill, J.; Mazeh, T.; Ribas, I.

    2011-11-01

    Exoplanet missions such as COROT and Kepler are providing precise photometric follow-up data of new kinds of variable stars undetected till now. Beaming binaries are among these objects. On these binary systems, the orbital motion of their components is fast enough to produce a detectable modulation on the received flux due to relativistic effects (Zucker et al. 2007). The great advantage of these systems is that it is possible to reconstruct the radial velocity curve of the system from this photometric modulation and thus, orbital parameters such as the mass ratio and the semi-major axis can be estimated from photometry without the necessity of spectroscopic follow-up. In this poster, we briefly introduce the analysis of this kind of binary systems and in particular, the eclipsing cases.

  2. Binary Planets

    NASA Astrophysics Data System (ADS)

    Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

    2014-11-01

    Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

  3. Microlensing Signature of Binary Black Holes

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  4. Separation in 5 Msun Binaries

    NASA Astrophysics Data System (ADS)

    Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

    2013-01-01

    Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

  5. Synthesis and characterization of an HSP27-targeted nanoprobe for in vivo photoacoustic imaging of early nerve injury.

    PubMed

    Chen, Hongjiang; Yang, Sihua; Zhou, Ting; Xu, Jiankun; Hu, Jun; Xing, Da

    2016-08-01

    Imaging is routinely used for clinical and diagnostic purposes, but techniques capable of high specificity and resolution for the early detection of nerve injury are still limited. In this study, we found that heat shock protein 27 (HSP27) becomes highly upregulated within 3 to 7 days of nerve injury. Taking advantage of this expression pattern, we conjugated gold nanorods (GNRs) to HSP27-specific antibodies to generate a nanoprobe (GNR-HSP27Abs) that could be targeted to the site of nerve injury and detected by near-infrared photoacoustic imaging. Notably, photoacoustic images acquired 12hours after local administration of GNR-HSP27Abs demonstrated that the nanoprobe can distinguish between injured and uninjured nerves in rats. Taken together, these findings expand the application of nanoprobe-targeted photoacoustic imaging to the detection of injured nerves, and prompt further development of this novel imaging platform for clinical application. PMID:27046663

  6. Development of Multifunctional Fluorescent-Magnetic Nanoprobes for Selective Capturing and Multicolor Imaging of Heterogeneous Circulating Tumor Cells.

    PubMed

    Pramanik, Avijit; Vangara, Aruna; Viraka Nellore, Bhanu Priya; Sinha, Sudarson Sekhar; Chavva, Suhash Reddy; Jones, Stacy; Ray, Paresh Chandra

    2016-06-22

    Circulating tumor cells (CTC) are highly heterogeneous in nature due to epithelial-mesenchymal transition (EMT), which is the major obstacle for CTC analysis via "liquid biopsy". This article reports the development of a new class of multifunctional fluorescent-magnetic multicolor nanoprobes for targeted capturing and accurate identification of heterogeneous CTC. A facile design approach for the synthesis and characterization of bioconjugated multifunctonal nanoprobes that exhibit excellent magnetic properties and emit very bright and photostable multicolor fluorescence at red, green, and blue under 380 nm excitation is reported. Experimental data presented show that the multifunctional multicolor nanoprobes can be used for targeted capture and multicolor fluorescence mapping of heterogeneous CTC and can distinguish targeted CTC from nontargeted cells. PMID:27255574

  7. Gold on paper-paper platform for Au-nanoprobe TB detection.

    PubMed

    Veigas, Bruno; Jacob, Jorge M; Costa, Mafalda N; Santos, David S; Viveiros, Miguel; Inácio, João; Martins, Rodrigo; Barquinha, Pedro; Fortunato, Elvira; Baptista, Pedro Viana

    2012-11-21

    Tuberculosis (TB) remains one of the most serious infectious diseases in the world and the rate of new cases continues to increase. The development of cheap and simple methodologies capable of identifying TB causing agents belonging to the Mycobacterium tuberculosis Complex (MTBC), at point-of-need, in particular in resource-poor countries where the main TB epidemics are observed, is of paramount relevance for the timely and effective diagnosis and management of patients. TB molecular diagnostics, aimed at reducing the time of laboratory diagnostics from weeks to days, still require specialised technical personnel and labour intensive methods. Recent nanotechnology-based systems have been proposed to circumvent these limitations. Here, we report on a paper-based platform capable of integrating a previously developed Au-nanoprobe based MTBC detection assay-we call it "Gold on Paper". The Au-nanoprobe assay is processed and developed on a wax-printed microplate paper platform, allowing unequivocal identification of MTBC members and can be performed without specialised laboratory equipment. Upon integration of this Au-nanoprobe colorimetric assay onto the 384-microplate, differential colour scrutiny may be captured and analysed with a generic "smartphone" device. This strategy uses the mobile device to digitalise the intensity of the colour associated with each colorimetric assay, perform a Red Green Blue (RGB) analysis and transfer relevant information to an off-site lab, thus allowing for efficient diagnostics. Integration of the GPS location metadata of every test image may add a new dimension of information, allowing for real-time epidemiologic data on MTBC identification. PMID:23000923

  8. Nanoprobe studies: Electrical transport in carbon nanotubes and crystal structure of aluminum nitride surfaces

    NASA Astrophysics Data System (ADS)

    Biswas, Sujit Kumar

    Nanoprobes are an extraordinary set of experimental tools that allow fabrication, manipulation, and measurement in nano-scale systems. The primary use of a nanoprobe for imaging tiny objects is supplemented by powerful electrical techniques, namely scanning surface potential microscopy and current sensing atomic force microscopy. They allow us to measure potential, and current in carbon nanotube circuits. Nanoprobes are superior to conventional two- or four-probe measurements because they can provide spatial information of local electronic properties. This makes them highly attractive in studying junctions and contacts with carbon nanotubes. We have studied single-walled carbon nanotube circuits, forming junctions to other nanotubes. The experimental results indicate that these junctions act like potential barriers of about 50 meV that can confine electrons with an effective mass of 0.003 me , within nanotube channels of length 0.5 mum lying in-between two such potential barriers. This leads to quantization of the channel, forming a resonant tunneling structure. We have also found that single-walled nanotubes have phase coherence lengths of the order of 1 mum. This leads to situations where the electron interference effects at scattering centers need to be considered. We have seen direct evidence of this, in the non-linear resistance increase within nanotubes with few defects. Ambipolar transistor behavior was measured in a p-type single-walled nanotube circuit that showed electron injection across the Schottky junction at high positive bias. We have also studied multi-walled carbon nanotube circuits using scanning potential microscopy, and found that a back gate potential can vary the resistance of the channel. Vertical nanotube arrays, suitable for interconnects, were also measured. These hollow multi-walled nanotube channels were about 45 nm in diameter, and 50 mum in length, fabricated in an anodized alumina template. We found that these structures could

  9. Measurement of minority carrier diffusion lengths in GaAs nanowires by a nanoprobe technique

    NASA Astrophysics Data System (ADS)

    Darbandi, A.; Watkins, S. P.

    2016-07-01

    Minority carrier diffusion lengths in both p-type and n-type GaAs nanowires were studied using electron beam induced current by means of a nanoprobe technique without lithographic processing. The diffusion lengths were determined for Au/GaAs rectifying junctions as well as axial p-n junctions. By incorporating a thin lattice-matched InGaP passivating shell, a 2-fold enhancement in the minority carrier diffusion lengths and one order of magnitude reduction in the surface recombination velocity were achieved.

  10. X-ray-Induced Shortwave Infrared Biomedical Imaging Using Rare-Earth Nanoprobes

    PubMed Central

    2015-01-01

    Shortwave infrared (SWIR or NIR-II) light provides significant advantages for imaging biological structures due to reduced autofluorescence and photon scattering. Here, we report on the development of rare-earth nanoprobes that exhibit SWIR luminescence following X-ray irradiation. We demonstrate the ability of X-ray-induced SWIR luminescence (X-IR) to monitor biodistribution and map lymphatic drainage. Our results indicate X-IR imaging is a promising new modality for preclinical applications and has potential for dual-modality molecular disease imaging. PMID:25485705

  11. Small-Protein-Stabilized Semiconductor Nanoprobe for Targeted Imaging of Cancer Cells.

    PubMed

    Zhao, Ning; Liu, Siyu; Jiang, Qike; Lan, Tian; Cheng, Zhen; Liu, Hongguang

    2016-07-01

    Recently, semiconductor nanoparticles such as quantum dots (QDs) have attracted significant attention for bioimaging. Complex chemical functionalization, surface modification, and bioconjugation chemistry are generally required to tag biomolecules to QDs for imaging of different biomarkers. In this study, we report a simple method for production of QDs stabilized by the small protein, Affibody (AF-QDs) for fluorescent imaging of the human epidermal growth factor receptor type 2 (HER2) in human A549 lung cancer cells. This one-pot synthesis of AF-QDs avoids complex chemical conjugation procedures and demonstrates a promising approach for the preparation of fluorescent nanoprobes for imaging of cancer targets. PMID:27123671

  12. CXCR-4 Targeted, Short Wave Infrared (SWIR) Emitting Nanoprobes for Enhanced Deep Tissue Imaging and Micrometastatic Lesion Detection

    PubMed Central

    Zevon, Margot; Ganapathy, Vidya; Kantamneni, Harini; Mingozzi, Marco; Kim, Paul; Adler, Derek; Sheng, Yang; Tan, Mei Chee; Pierce, Mark; Riman, Richard E.; Roth, Charles M.; Moghe, Prabhas V.

    2016-01-01

    Realizing the promise of precision medicine in cancer therapy depends on identifying and tracking of cancerous growths in order to maximize treatment options and improve patient outcomes. However, this goal of early detection remains unfulfilled by current clinical imaging techniques that fail to detect diseased lesions, due to their small size and sub-organ localization. With proper probes, optical imaging techniques can overcome this limitation by identifying the molecular phenotype of tumors at both macroscopic and microscopic scales. In this study, we propose the first use of nanophotonic short wave infrared technology to molecularly phenotype small sub-surface lesions for more sensitive detection and improved patient outcomes. To this end, we designed human serum albumin encapsulated rare-earth (RE) nanoparticles (ReANCs)[1, 2] with ligands for targeted lesion imaging. AMD3100, an antagonist to CXCR4 (a chemokine receptor involved in cell motility and a classic marker of cancer metastasis) was adsorbed onto ReANCs to form functionalized ReANCs (fReANCs). Functionalized nanoparticles were able to discriminate and preferentially accumulate in receptor positive lesions when injected intraperitoneally in a subcutaneous tumor model. Additionally, fReANCs, administered intravenously, were able to target sub-tissue tumor micro-lesions, at a maximum depth of 10.5 mm, in a lung metastatic model of breast cancer. Internal lesions identified with fReANCs were 2.25 times smaller than those detected with unfunctionalized ReANCs (p < .01) with the smallest tumor being 18.9 mm3. Thus, we present an integrated nanoprobe detection platform that allows target-specific identification of sub-tissue cancerous lesions. PMID:26514367

  13. A Next-Generation Hard X-Ray Nanoprobe Beamline for In Situ Studies of Energy Materials and Devices

    NASA Astrophysics Data System (ADS)

    Maser, Jörg; Lai, Barry; Buonassisi, Tonio; Cai, Zhonghou; Chen, Si; Finney, Lydia; Gleber, Sophie-Charlotte; Jacobsen, Chris; Preissner, Curt; Roehrig, Chris; Rose, Volker; Shu, Deming; Vine, David; Vogt, Stefan

    2014-01-01

    The Advanced Photon Source is developing a suite of new X-ray beamlines to study materials and devices across many length scales and under real conditions. One of the flagship beamlines of the APS upgrade is the In Situ Nanoprobe (ISN) beamline, which will provide in situ and operando characterization of advanced energy materials and devices under varying temperatures, gas ambients, and applied fields, at previously unavailable spatial resolution and throughput. Examples of materials systems include inorganic and organic photovoltaic systems, advanced battery systems, fuel cell components, nanoelectronic devices, advanced building materials and other scientifically and technologically relevant systems. To characterize these systems at very high spatial resolution and trace sensitivity, the ISN will use both nanofocusing mirrors and diffractive optics to achieve spots sizes as small as 20 nm. Nanofocusing mirrors in Kirkpatrick-Baez geometry will provide several orders of magnitude increase in photon flux at a spatial resolution of 50 nm. Diffractive optics such as zone plates and/or multilayer Laue lenses will provide a highest spatial resolution of 20 nm. Coherent diffraction methods will be used to study even small specimen features with sub-10 nm relevant length scale. A high-throughput data acquisition system will be employed to significantly increase operations efficiency and usability of the instrument. The ISN will provide full spectroscopy capabilities to study the chemical state of most materials in the periodic table, and enable X-ray fluorescence tomography. In situ electrical characterization will enable operando studies of energy and electronic devices such as photovoltaic systems and batteries. We describe the optical concept for the ISN beamline, the technical design, and the approach for enabling a broad variety of in situ studies. We furthermore discuss the application of hard X-ray microscopy to study defects in multi-crystalline solar cells, one

  14. A Next-Generation Hard X-Ray Nanoprobe Beamline for In Situ Studies of Energy Materials and Devices

    SciTech Connect

    Maser, Jong; Lai, Barry; Buonassisi, Toni; Cai, Zhonghou; Chen, Si; Finney, Lydia; Gleber, Sophie-Charlotte; Jacobsen, Chris; Preissner, Curt; Chris Roehrig; Rose, Volker; Shu, Deming; Vine, David; Vogt, Stefan

    2013-08-20

    The Advanced Photon Source is developing a suite of new X-ray beamlines to study materials and devices across many length scales and under real conditions. One of the flagship beamlines of the APS upgrade is the In Situ Nanoprobe (ISN) beamline, which will provide in situ and operando characterization of advanced energy materials and devices under varying temperatures, gas ambients, and applied fields, at previously unavailable spatial resolution and throughput. Examples of materials systems include inorganic and organic photovoltaic systems, advanced battery systems, fuel cell components, nanoelectronic devices, advanced building materials and other scientifically and technologically relevant systems. To characterize these systems at very high spatial resolution and trace sensitivity, the ISN will use both nanofocusing mirrors and diffractive optics to achieve spots sizes as small as 20 nm. Nanofocusing mirrors in Kirkpatrick–Baez geometry will provide several orders of magnitude increase in photon flux at a spatial resolution of 50 nm. Diffractive optics such as zone plates and/or multilayer Laue lenses will provide a highest spatial resolution of 20 nm. Coherent diffraction methods will be used to study even small specimen features with sub-10 nm relevant length scale. A high-throughput data acquisition system will be employed to significantly increase operations efficiency and usability of the instrument. The ISN will provide full spectroscopy capabilities to study the chemical state of most materials in the periodic table, and enable X-ray fluorescence tomography. In situ electrical characterization will enable operando studies of energy and electronic devices such as photovoltaic systems and batteries. We also describe the optical concept for the ISN beamline, the technical design, and the approach for enabling a broad variety of in situ studies. Furthermore, we discuss the application of hard X-ray microscopy to study defects in multi-crystalline solar

  15. Ratiometric Fluorescence Nanoprobes for Subcellular pH Imaging with a Single-Wavelength Excitation in Living Cells.

    PubMed

    Pan, Wei; Wang, Honghong; Yang, Limin; Yu, Zhengze; Li, Na; Tang, Bo

    2016-07-01

    Abnormal pH values in the organelles are closely associated with inappropriate cellular functions and many diseases. Monitoring subcellular pH values and their variations is significant in biological processes occurring in living cells and tissues. Herein, we develop a series of ratiometric fluorescence nanoprobes for quantification and imaging of pH values with a single-wavelength excitation in cytoplasm, lysosomes, and mitochondria. The nanoprobes consist of mesoporous silica nanoparticles assembled with aminofluorescein as the recognition unit for pH measurement and ethidium bromide as reference fluorophore. Further conjugation of subcellular targeting moiety enables the nanoprobes to specifically target lysosome and mitochondria. Confocal fluorescence imaging demonstrated that the nanoprobes could effectively monitor the pH fluctuations from 5.0 to 8.3 in living cells by ratio imaging with 488 nm excitation. Subcellular pH determination and imaging in lysosome and mitochondria could also be achieved in different conditions. The current method can offer a general strategy to determine subcellular analytes and investigate the interactions in biological samples. PMID:27295434

  16. Amplified inhibition of the electrochemical signal of ferrocene by enzyme-functionalized graphene oxide nanoprobe for ultrasensitive immunoassay.

    PubMed

    Lai, Guosong; Cheng, Hui; Xin, Dinghong; Zhang, Haili; Yu, Aimin

    2016-01-01

    A nanoprobe-induced signal inhibition mechanism was designed for ultrasensitive electrochemical immunoassay at a chitosan-ferrocene (CS-Fc) based immunosensor. The nanoprobe was prepared by covalently loading signal antibody and high-content horseradish peroxidase (HRP) on the graphene oxide (GO) nanocarrier. The immunosensor was prepared through the stepwise assembly of gold nanoparticles (Au NPs) and capture antibody at a CS-Fc modified electrode. After sandwich immunoreaction, the GO-HRP nanoprobes were quantitatively captured onto the immunosensor surface and thus induced the production of a layer of insoluble film through the enzymatically catalytic reaction of the HRP labels. Both the dielectric immunocomplex formed on the immunosensor surface and the enzymatic precipitate with low electroconductivity led to the electrochemical signal decease of the Fc indicator, which was greatly amplified by the multi-enzyme signal amplification of the nanoprobe. Based on this amplified signal inhibition mechanism, a new ultrasensitive electrochemical immunoassay method was developed. Using carcinoembryonic antigen as a model analyte, this method showed a wide linear range over 5 orders of magnitude with a detection limit down to 0.54 pg/mL. Besides, the immunosensor showed good specificity, acceptable reproducibility and stability as well as satisfactory reliability for the serum sample analysis. PMID:26703270

  17. A novel photoacoustic nanoprobe of ICG@PEG-Ag2S for atherosclerosis targeting and imaging in vivo.

    PubMed

    Wu, Chenxin; Zhang, Yejun; Li, Zhen; Li, Chunyan; Wang, Qiangbin

    2016-07-01

    Atherosclerosis is a major cause of cardiovascular and cerebrovascular diseases that have high mortality and disability rates. Because of its unclear pathogenic mechanism and heterogeneous distribution feature, it is still a big challenge to achieve precise diagnosis and therapy of atherosclerosis at its early stage in vivo. Herein, we fabricated a new ICG@PEG-Ag2S nanoprobe by a simple self-assembly of DT-Ag2S QDs, amphipathic C18/PEG polymer molecules and ICG. The ICG@PEG-Ag2S nanoprobe showed relatively long blood retention and was selectively accumulated in the region of atherosclerotic plaque due to the lipophilicity of the C18 chain to the atherosclerosis microenvironment, and thus the atherosclerosis was real-time monitored by high contrast-enhanced photoacoustic (PA) imaging of ICG. Combining the high signal-to-noise ratio (SNR) and high spatial resolution fluorescence imaging of Ag2S QDs in the second near-infrared window (NIR-II) and related histological assessment in vitro, the feasibility of this new nanoprobe for atherosclerosis targeting in an Apoe(-/-) mouse model was verified. Additionally, hemolysis and coagulation assays of the ICG@PEG-Ag2S revealed its decent hemocompatibility and no histological changes were observed in the main organs of the mouse. Such a simple, multifunctional nanoprobe for targeting and PA imaging of atherosclerosis will have a great potential for future clinical applications. PMID:26853187

  18. Construction of an upconversion nanoprobe with few-atom silver nanoclusters as the energy acceptor.

    PubMed

    Xiao, Yan; Zeng, Lingyu; Xia, Tian; Wu, Zhengjun; Liu, Zhihong

    2015-04-27

    Herein we report that few-atom silver nanoclusters (Ag NCs) can be effective energy acceptors for upconversion phosphors (UCPs). A luminescence resonance energy transfer (LRET) probe for biothiols was constructed by decorating UCPs with dithiol-stabilized Ag NCs. Owing to the unique properties of ultrasmall NCs, properties which bridge the gap between those of small molecules and those of nanoparticles, the use of approximately 1.9 nm Ag NCs as energy acceptors endows the probe with high energy-transfer efficiency, good biocompatibility, and flexibility. The UCP-Ag NC nanoprobe enables rapid and robust target assay in solutions. It was also uploaded into living cells and used to detect intracellular biothiol levels with high discrimination. Moreover, the probe shows transportability in vivo and can be used for tissue imaging. The facile growth of few-atom metal NCs on diverse templates may enable the development of various nanoprobes combining UCPs and metal NCs. PMID:25753304

  19. A value-added exopolysaccharide as a coating agent for MRI nanoprobes.

    PubMed

    Palma, Susana I C J; Rodrigues, Carlos A V; Carvalho, Alexandra; Morales, Maria del Puerto; Freitas, Filomena; Fernandes, Alexandra R; Cabral, Joaquim M S; Roque, Ana C A

    2015-09-14

    Fucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA-stabilized nanoparticles (MNP-DMSA) resulted in a hybrid magnetic-biopolymeric nanosystem (MNP-DMSA-EPS) with a hydrodynamic size of 170 nm, a negative surface charge under physiological conditions and transverse to longitudinal relaxivity ratio, r2/r1, of 148. In vitro studies with two human cell lines (colorectal carcinoma - HCT116 - and neural stem/progenitor cells - ReNcell VM) showed that EPS promotes internalization of nanoparticles in both cell lines. In vitro MRI cell phantoms showed a superior performance of MNP-DMSA-EPS in ReNcell VM, for which the iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12-20 μg Fe per ml) and short incubation times. Furthermore, ReNcell VM multipotency was not affected by culture in the presence of MNP-DMSA or MNP-DMSA-EPS for 14 days. Our study suggests that Fucopol-coated MNPs represent useful cell labeling nanoprobes for MRI. PMID:26186402

  20. Smart nanoprobes for ultrasensitive detection of breast cancer via magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Lee, Jaemin; Yang, Jaemoon; Seo, Sung-Baek; Ko, Hyun-Ju; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2008-12-01

    Antibody-conjugated hydrophilic magnetic nanocrystals for use as smart nanoprobes were developed for ultrasensitive detection of breast cancer via magnetic resonance (MR) imaging. MnFe2O4 nanocrystals (MNCs) for use as MR imaging contrast agents were synthesized by thermal decomposition to take advantage of their MR signal enhancement effect. The MNC surfaces were then modified with amphiphilic tri-block copolymers (dicarboxy poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)), not only allowing the MNCs to transfer from the organic to the aqueous phase, but also increasing the colloidal stability of the MNCs by masking poly(ethylene glycol). The physicochemical properties of the synthesized hydrophilic magnetic nanocrystals (HMNCs) were fully investigated. Trastuzumab (TZ), a monoclonal antibody against human epidermal growth factor receptor (HER2/neu), was further conjugated on the surface of HMNCs to specifically target HER2/neu over-expressed breast cancer cells. MR imaging analysis of target cells treated with TZ-conjugated HMNCs (TZ-HMNCs) clearly demonstrated their potential as high-performance nanoprobes for selective imaging.

  1. Multiple functional nanoprobe for contrast-enhanced bimodal cellular imaging and targeted therapy.

    PubMed

    Meng, Hong-Min; Lu, Limin; Zhao, Xu-Hua; Chen, Zhuo; Zhao, Zilong; Yang, Chan; Zhang, Xiao-Bing; Tan, Weihong

    2015-04-21

    Many one-photon fluorescence-based theranostic nanosystems have been developed for simultaneous therapeutic intervention/monitoring for various types of cancers. However, for early diagnosis of cancer, two-photon fluorescence microscopy (TPFM) can realize deep-tissue imaging with higher spatial resolution. In this study, we first report a multiple functional nanoprobe for contrast-enhanced bimodal cellular imaging and targeted therapy. Components of the nanoprobe include (1) two-photon dye-doped mesoporous silica nanoparticles (TPD-MSNs); (2) MnO2 nanosheets that act as a (i) gatekeeper for TPD-MSNs, (ii) quencher for TP fluorescence, and (iii) contrast agent for MRI; (3) cancer cell-targeting aptamers. Guided by aptamers, TPD-MSNs are rapidly internalized into the target cells. Next, intracellular glutathione reduces MnO2 to Mn(2+) ions, resulting in contrast-enhanced TP fluorescence and magnetic resonance signal for cellular imaging. Meanwhile, preloaded doxorubicin and Chlorin e6 are released for chemotherapy and photodynamic therapy, respectively, with a synergistic effect and significantly enhanced therapeutic efficacy. PMID:25791340

  2. Active-target T1-weighted MR Imaging of Tiny Hepatic Tumor via RGD Modified Ultra-small Fe3O4 Nanoprobes

    PubMed Central

    Jia, Zhengyang; Song, Lina; Zang, Fengchao; Song, Jiacheng; Zhang, Wei; Yan, Changzhi; Xie, Jun; Ma, Zhanlong; Ma, Ming; Teng, Gaojun; Gu, Ning; Zhang, Yu

    2016-01-01

    Developing ultrasensitive contrast agents for the early detection of malignant tumors in liver is highly demanded. Constructing hepatic tumors specific targeting probes could provide more sensitive imaging information but still faces great challenges. Here we report a novel approach for the synthesis of ultra-small Fe3O4 nanoparticles conjugated with c(RGDyK) and their applications as active-target T1-weighted magnetic resonance imaging (MRI) contrast agent (T1-Fe3O4) for imaging tiny hepatic tumors in vivo. RGD-modified T1-Fe3O4 nanoprobes exhibited high r1 of 7.74 mM-1s-1 and ultralow r2/r1 of 2.8 at 3 T, reflecting their excellent T1 contrast effect at clinically relevant magnetic field. High targeting specificity together with favorable biocompatibility and strong ability to resist against non-specific uptake were evaluated through in vitro studies. Owing to the outstanding properties of tumor angiogenesis targeting with little phagocytosis in liver parenchyma, hepatic tumor as small as 2.2 mm was successfully detected via the T1 contrast enhancement of RGD-modified T1-Fe3O4. It is emphasized that this is the first report on active-target T1 imaging of hepatic tumors, which could not only significantly improve diagnostic sensitivity, but also provide post therapeutic assessments for patients with liver cancer. PMID:27570550

  3. Active-target T1-weighted MR Imaging of Tiny Hepatic Tumor via RGD Modified Ultra-small Fe3O4 Nanoprobes.

    PubMed

    Jia, Zhengyang; Song, Lina; Zang, Fengchao; Song, Jiacheng; Zhang, Wei; Yan, Changzhi; Xie, Jun; Ma, Zhanlong; Ma, Ming; Teng, Gaojun; Gu, Ning; Zhang, Yu

    2016-01-01

    Developing ultrasensitive contrast agents for the early detection of malignant tumors in liver is highly demanded. Constructing hepatic tumors specific targeting probes could provide more sensitive imaging information but still faces great challenges. Here we report a novel approach for the synthesis of ultra-small Fe3O4 nanoparticles conjugated with c(RGDyK) and their applications as active-target T1-weighted magnetic resonance imaging (MRI) contrast agent (T1-Fe3O4) for imaging tiny hepatic tumors in vivo. RGD-modified T1-Fe3O4 nanoprobes exhibited high r1 of 7.74 mM(-1)s(-1) and ultralow r2/r1 of 2.8 at 3 T, reflecting their excellent T1 contrast effect at clinically relevant magnetic field. High targeting specificity together with favorable biocompatibility and strong ability to resist against non-specific uptake were evaluated through in vitro studies. Owing to the outstanding properties of tumor angiogenesis targeting with little phagocytosis in liver parenchyma, hepatic tumor as small as 2.2 mm was successfully detected via the T1 contrast enhancement of RGD-modified T1-Fe3O4. It is emphasized that this is the first report on active-target T1 imaging of hepatic tumors, which could not only significantly improve diagnostic sensitivity, but also provide post therapeutic assessments for patients with liver cancer. PMID:27570550

  4. A value-added exopolysaccharide as a coating agent for MRI nanoprobes

    NASA Astrophysics Data System (ADS)

    Palma, Susana I. C. J.; Rodrigues, Carlos A. V.; Carvalho, Alexandra; Morales, Maria Del Puerto; Freitas, Filomena; Fernandes, Alexandra R.; Cabral, Joaquim M. S.; Roque, Ana C. A.

    2015-08-01

    Fucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA-stabilized nanoparticles (MNP-DMSA) resulted in a hybrid magnetic-biopolymeric nanosystem (MNP-DMSA-EPS) with a hydrodynamic size of 170 nm, a negative surface charge under physiological conditions and transverse to longitudinal relaxivity ratio, r2/r1, of 148. In vitro studies with two human cell lines (colorectal carcinoma - HCT116 - and neural stem/progenitor cells - ReNcell VM) showed that EPS promotes internalization of nanoparticles in both cell lines. In vitro MRI cell phantoms showed a superior performance of MNP-DMSA-EPS in ReNcell VM, for which the iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12-20 μg Fe per ml) and short incubation times. Furthermore, ReNcell VM multipotency was not affected by culture in the presence of MNP-DMSA or MNP-DMSA-EPS for 14 days. Our study suggests that Fucopol-coated MNPs represent useful cell labeling nanoprobes for MRI.Fucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA

  5. Development of an aptamer-conjugated fluorescent nanoprobe for MMP2

    PubMed Central

    2014-01-01

    Matrix metalloproteinase 2 (MMP2) plays critical roles in various diseases, such as atherosclerosis and cancer, and has been suggested to contribute to the instability of atherosclerotic plaque. To visualize MMP2 in pathologic tissues, we developed an aptamer targeting MMP2 protein by performing eight rounds of modified DNA systematic evolution of ligands by exponential enrichment (SELEX). The aptamer showed high affinity for MMP2 (Kd = 5.59 nM), precipitated MMP2, and detected MMP2 protein in pathological tissues such as atherosclerotic plaque and gastric cancer tissues. Furthermore, a MMP2 aptamer-conjugated fluorescent nanoprobe successfully visualized atherosclerotic plaques in apolipoprotein E (ApoE) knockout mice. These results suggest that the devised MMP2 aptamer could be useful for the development of various diagnostic tools. PMID:24589243

  6. Microgel photonics and lab on fiber technology for advanced label-free fiber optic nanoprobes

    NASA Astrophysics Data System (ADS)

    Giaquinto, M.; Micco, A.; Aliberti, A.; Ricciardi, A.; Ruvo, M.; Cutolo, A.; Cusano, A.

    2016-05-01

    We experimentally demonstrate a novel optical fiber label free optrode platform resulting from the integration between two rapidly emerging technologies such as Lab-on-Fiber Technology (LOFT) and Microgel Photonics (MPs). The device consists of a microgel (MG) layer painted on a metallic slabs supporting plasmonic resonances, directly integrated on the optical fiber tip. A molecular binding event induces significant changes in the MG layer thickness (and consequently in its 'equivalent' refractive index) resulting in an evident wavelength shift of the resonant feature. As a case of study, glucose-responsive MGs have been synthesized by incorporating into the gel matrix boronic acid moieties, whose interaction with glucose rules the driving forces for gel swelling. Our results pave the way for new technological routes aimed to develop advanced label free fiber optic nanoprobes.

  7. Development of an aptamer-conjugated fluorescent nanoprobe for MMP2

    NASA Astrophysics Data System (ADS)

    Han, Myoung-Eun; Baek, Sungmin; Kim, Hyun-Jung; Lee, Jung Hwan; Ryu, Sung-Ho; Oh, Sae-Ock

    2014-03-01

    Matrix metalloproteinase 2 (MMP2) plays critical roles in various diseases, such as atherosclerosis and cancer, and has been suggested to contribute to the instability of atherosclerotic plaque. To visualize MMP2 in pathologic tissues, we developed an aptamer targeting MMP2 protein by performing eight rounds of modified DNA systematic evolution of ligands by exponential enrichment (SELEX). The aptamer showed high affinity for MMP2 ( K d = 5.59 nM), precipitated MMP2, and detected MMP2 protein in pathological tissues such as atherosclerotic plaque and gastric cancer tissues. Furthermore, a MMP2 aptamer-conjugated fluorescent nanoprobe successfully visualized atherosclerotic plaques in apolipoprotein E (ApoE) knockout mice. These results suggest that the devised MMP2 aptamer could be useful for the development of various diagnostic tools.

  8. Coherent Bragg nanodiffraction at the hard X-ray Nanoprobe beamline

    PubMed Central

    Hruszkewycz, S. O.; Holt, M. V.; Maser, J.; Murray, C. E.; Highland, M. J.; Folkman, C. M.; Fuoss, P. H.

    2014-01-01

    Bragg coherent diffraction with nanofocused hard X-ray beams provides unique opportunities for quantitative in situ studies of crystalline structure in nanoscale regions of complex materials and devices by a variety of diffraction-based techniques. In the case of coherent diffraction imaging, a major experimental challenge in using nanoscale coherent beams is maintaining a constant scattering volume such that coherent fringe visibility is maximized and maintained over the course of an exposure lasting several seconds. Here, we present coherent Bragg diffraction patterns measured from different nanostructured thin films at the Sector 26 Nanoprobe beamline at the Advanced Photon Source and demonstrate that with nanoscale positional control, coherent diffraction patterns can be measured with source-limited fringe visibilities more than 50% suitable for imaging by coherent Bragg ptychography techniques. PMID:24470418

  9. Highly sensitive ochratoxin A impedimetric aptasensor based on the immobilization of azido-aptamer onto electrografted binary film via click chemistry.

    PubMed

    Hayat, Akhtar; Sassolas, Audrey; Marty, Jean-Louis; Radi, Abd-Elgawad

    2013-01-15

    The aptamer immobilization onto organized mixed layers of diazonium salts via click chemistry was explored. The immobilized aptamer was employed in the fabrication of a highly sensitive and reusable electrochemical impedimetric aptasensor for the detection of ochratoxin A (OTA). The screen-printed carbon electrodes (SPCEs) were first modified by electrografting of a protected 4-((trimethylsilyl)ethynyl) benzene (TMSi-Eth-Ar) layer followed by a second one of p-nitrobenzene (p-NO(2)-Ar) by means of electrochemical reduction of their corresponding diazonium salts, (TMSi-Eth-Ar-N(2)(+)) and (p-NO(2)-ArN(2)(+)). After deprotection, a layer with active ethynyl groups was obtained. In the presence of copper (I) catalyst, the ethynyl groups reacted efficiently with aptamer bearing an azide function, thus forming a covalent 1,2,3-triazole linkage. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of ferri/ferrocyanide redox probe [Fe(CN)(6)](4-/3-) were used to characterize each step in the aptasensor development. The increase in electron-transfer resistance (R(et)) values due to the specific aptamer-OTA interaction was proportional to the concentration of OTA in a range between 1.25 ng/L and 500 ng/L, with a detection limit of 0.25 ng/L. PMID:23200352

  10. Simultaneous Visualization of Multiple mRNAs and Matrix Metalloproteinases in Living Cells Using a Fluorescence Nanoprobe.

    PubMed

    Pan, Wei; Yang, Huijun; Li, Na; Yang, Limin; Tang, Bo

    2015-04-13

    Simultaneous monitoring of multiple tumour markers is of great significance for improving the accuracy of early cancer detection. In this study, a fluorescence nanoprobe has been prepared that can simultaneously monitor and visualize multiple mRNAs and matrix metalloproteinases (MMPs) in living cells. Confocal fluorescence imaging results indicate that the nanoprobe could effectively distinguish between cancer cells and normal cells even if one tumour maker of normal cells was overexpressed. Furthermore, it can detect changes in the expression levels of mRNAs and MMPs in living cells. The current approach could provide new tools for early cancer detection and monitoring the changes in expression levels of biomarkers during tumour progression. PMID:25752514

  11. Microwave-assisted polyol synthesis of gadolinium-doped green luminescent carbon dots as a bimodal nanoprobe.

    PubMed

    Gong, Ningqiang; Wang, Hao; Li, Shuai; Deng, Yunlong; Chen, Xiao'ai; Ye, Ling; Gu, Wei

    2014-09-16

    The development of multimodal nanoprobes is highly desired in medical imaging because it integrates the advantages of multiple imaging modes. In this study, the gadolinium-doped green luminescent carbon dots (Gd-CDs) were prepared by the simple one-step microwave-assisted polyol method. The obtained Gd-CDs emitted a unique green photoluminescence with a quantum yield of 5.4%. The Gd-CDs exhibited a low cytotoxicity and could optically label the C6 glioma cells. Meanwhile, the r1 relaxivity of Gd-CDs was measured to be 11.356 mM(-1) s(-1). This high r1 value together with the r2/r1 ratio close to 1 nominates Gd-CDs as an excellent T1 contrast agent for magnetic resonance imaging. These Gd-CDs combining two complementary imaging modalities are therefore a promising bimodal nanoprobe in medical imaging for a better diagnosis. PMID:25157595

  12. A novel photoacoustic nanoprobe of ICG@PEG-Ag2S for atherosclerosis targeting and imaging in vivo

    NASA Astrophysics Data System (ADS)

    Wu, Chenxin; Zhang, Yejun; Li, Zhen; Li, Chunyan; Wang, Qiangbin

    2016-06-01

    Atherosclerosis is a major cause of cardiovascular and cerebrovascular diseases that have high mortality and disability rates. Because of its unclear pathogenic mechanism and heterogeneous distribution feature, it is still a big challenge to achieve precise diagnosis and therapy of atherosclerosis at its early stage in vivo. Herein, we fabricated a new ICG@PEG-Ag2S nanoprobe by a simple self-assembly of DT-Ag2S QDs, amphipathic C18/PEG polymer molecules and ICG. The ICG@PEG-Ag2S nanoprobe showed relatively long blood retention and was selectively accumulated in the region of atherosclerotic plaque due to the lipophilicity of the C18 chain to the atherosclerosis microenvironment, and thus the atherosclerosis was real-time monitored by high contrast-enhanced photoacoustic (PA) imaging of ICG. Combining the high signal-to-noise ratio (SNR) and high spatial resolution fluorescence imaging of Ag2S QDs in the second near-infrared window (NIR-II) and related histological assessment in vitro, the feasibility of this new nanoprobe for atherosclerosis targeting in an Apoe-/- mouse model was verified. Additionally, hemolysis and coagulation assays of the ICG@PEG-Ag2S revealed its decent hemocompatibility and no histological changes were observed in the main organs of the mouse. Such a simple, multifunctional nanoprobe for targeting and PA imaging of atherosclerosis will have a great potential for future clinical applications.Atherosclerosis is a major cause of cardiovascular and cerebrovascular diseases that have high mortality and disability rates. Because of its unclear pathogenic mechanism and heterogeneous distribution feature, it is still a big challenge to achieve precise diagnosis and therapy of atherosclerosis at its early stage in vivo. Herein, we fabricated a new ICG@PEG-Ag2S nanoprobe by a simple self-assembly of DT-Ag2S QDs, amphipathic C18/PEG polymer molecules and ICG. The ICG@PEG-Ag2S nanoprobe showed relatively long blood retention and was selectively

  13. Reagentless electrochemiluminescent detection of protein biomarker using graphene-based magnetic nanoprobes and poly-L-lysine as co-reactant.

    PubMed

    Liao, Ni; Zhuo, Ying; Chai, Ya-Qin; Xiang, Yun; Han, Jing; Yuan, Ruo

    2013-07-15

    This work described the construction of a reagentless and ultrasensitive electrochemiluminescence (ECL) immunosensor using poly-L-lysine as a co-reactant with Ru(bpy)3(2+) for signal amplification and magnetic Fe3O4 loaded graphene nanosheet as nanoprobes, which can achieve an impressive detection limit of 0.03 pg/mL human total 3,3',5-triiodothyronine (T3), a kind of diagnostic markers of thyroid disease. The bionanoprobes were prepared based on the coimmobilization of Ru(bpy)3(2+) and T3 detection antibody on the Fe3O4 loaded graphene nanosheet and the sensing interface was achieved by assembling T3 capture antibody on the gold nanoparticles (AuNPs) loaded electro-deposited L-lysine film modified bare glass carbon electrode (GCE). ECL responses were generated from the modified electrodes described above by just immersing them in phosphate buffer solutions (PBS) based on the sandwich-type immunoreactions. T3 was measured quantitatively in the range from 0.1 pg/mL to 10 ng/mL, which exhibits sufficiently high sensitivity and stability. The reagentless ECL immunoassay is a promising approach for the detection of a wide range of molecular analytes. PMID:23500362

  14. Long persistent near infrared luminescence nanoprobes LiGa5O8:Cr3+-PEG-OCH3 for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Fu, Xiaoyan; Liu, Chunlin; Shi, Junpeng; Man, Huizi; Xu, Jia; Zhang, Hongwu

    2014-09-01

    The Cr3+-doped LiGa5O8 nanoparticles (LGNPs) with long-persistent near-infrared phosphorescence were obtained through a sol-gel approach followed by heat treatment at 800 °C in air. The obtained results reveal that the nanoparticles with an average diameter of 100 nm are well defined and have pure structure of LiGa5O8. After illumination for 3 min using a 254 nm UV lamp, the LGNPs exhibit strong near-infrared peak at ca. 720 nm belonging to tissue transparency window which can last for more than 1 h. Via surface modified with PEG-5000-OCH3, the LGNPs-PEG-OCH3 exhibit excellent biocompatibility and low toxicity. Under in vitro pre-excitation using a 254 nm UV lamp for 3 min, the in vivo distribution of the LGNPs-PEG-OCH3 in the abdomen can be detected in real time for more than 1 h. All the results indicate that the LGNPs-PEG-OCH3 can be used as potential nanoprobes to realize in vivo, real time and long time imaging with high sensitivity.

  15. New type of redox nanoprobe: C60-based nanomaterial and its application in electrochemical immunoassay for doping detection.

    PubMed

    Han, Jing; Zhuo, Ying; Chai, Ya-Qin; Xiang, Yun; Yuan, Ruo

    2015-02-01

    Carbon nanomaterials were usually exploited as nanocarriers in an electrochemical immunosensor but rarely acted as redox nanoprobes. Herein, our motivation is to adequately utilize the inner redox activity of fullerene (C60) to obtain a new type of redox nanoprobe based on a hydrophilic C60 nanomaterial. First, C60 nanoparticles (C60NPs) were prepared by phase-transfer method and functionalized with amino-terminated polyamidoamine (PAMAM) to obtain the PAMAM decorated C60NPs (PAMAM-C60NPs) which have better hydrophilicity compared to that of unmodified C60NPs and possesses abundant amine groups for further modification. Following that, gold nanoparticles (nano-Au) were absorbed on the PAMAM-C60NPs surface, and the resultant Au-PAMAM-C60NPs were employed as a new type of redox nanoprobe and nanocarrier to label detection antibodies (Ab2). Doping control has become the biggest problem facing international sport. Erythropoietin (EPO) as a blood doping agent has been a hotspot in doping control. After sandwich-type immunoreaction between EPO (as a model) and Ab2-labeled Au-PAMAM-C60NPs, the resultant immunosensor was further incubated with a drop of tetraoctylammonium bromide (TOAB) which acts as booster to arouse the inner redox activity of Au-PAMAM-C60NPs, thus a pair of reversible redox peaks is observed. As a result, the proposed immunosensor shows a wide linear range and a relatively low detection limit for EPO. This strategy paves a new avenue for exploring the redox nanoprobe based on carbon nanomaterials in the electrochemical biosensor field. PMID:25547661

  16. Organometallic nanoprobe to enhance optical response on the polycyclic aromatic hydrocarbon benzo[a]pyrene immunoassay using SERS technology.

    PubMed

    Dribek, Mohamed; Rinnert, Emmanuel; Colas, Florent; Crassous, Marie-Pierre; Thioune, Néné; David, Catalina; de la Chapelle, Marc; Compère, Chantal

    2014-08-12

    We demonstrated the use of a new organometallic nanoprobe for competitive surface-enhanced Raman scattering (SERS) immunoassay devoted to the detection of polycyclic aromatic hydrocarbons (PAH) such as benzo[a]pyrene (BaP) in seawater. The nanoprobes are gold nanoparticles (GNPs) labeled by a Raman reporter, the 5,5'-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) and functionalized with monoclonal antibodies anti-BaP. The antibodies are bound with a high specificity to the analyte while the GNPs enhanced the Raman scattering of the DSNB. This type of immunoassay involved the grafting of BaP onto a sensing surface. Thus, NH2-terminated self-assembled monolayer is formed on the surface of gold substrate using cysteamine. Amines finally reacted with 6-formylbenzo[a]pyrene. So, this SERS detection involves four steps: (i) the nanoprobes are incubated with the sample; (ii) a drop of the mixture is then put onto the substrate; (iii) the surface is rinsed; and (iv) the surface is analyzed by Raman spectroscopy. To synthesize the nanoprobes, firstly, we prepared GNPs according to Frens' method. Then, GNPs were spontaneously labeled by the DSNB Raman reporter, thanks to a strong gold-sulfur interaction. Thereafter, BaP antibodies were cross-linked to the DSNB labeled GNPs by reaction of proteins primary amino groups with N-hydroxyl succinimide (NHS). Before use in SERS detection, their activity was controlled by surface plasmon resonance technique. The present method allows us to detect BaP at trace concentration (2 nmol/L). The results demonstrate that the proposed method has a great potential for application in the monitoring of seawater. PMID:25109469

  17. Transferrin-targeted magnetic/fluorescence micelles as a specific bi-functional nanoprobe for imaging liver tumor

    NASA Astrophysics Data System (ADS)

    Qi, Hui; Li, Zhengzheng; Du, Kai; Mu, Ketao; Zhou, Qing; Liang, Shuyan; Zhu, Wenzhen; Yang, Xiangliang; Zhu, Yanhong

    2014-10-01

    In order to delineate the location of the tumor both before and during operation, we developed targeted bi-functional polymeric micelles for magnetic resonance (MR) and fluorescence imaging in liver tumors. Hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) were loaded into the polymeric micelles through self-assembly of an amphiphilic block copolymer poly(ethylene glycol)-poly(ɛ-caprolactone). After, transferrin (Tf) and near-infrared fluorescence molecule Cy5.5 were conjugated onto the surface of the polymeric micelles to obtain the nanosized probe SPIO@PEG- b-PCL-Tf/Cy5.5 (SPPTC). Imaging capabilities of this nanoprobe were evaluated both in vitro and in vivo. The accumulation of SPPTC in HepG2 cells increased over SPIO@PEG- b-PCL-Cy5.5 (SPPC) by confocal microscopy. The targeted nanoprobe SPPTC possessed favorable properties on the MR and fluorescence imaging both in vitro and in vivo. The MTT results showed that the nanoprobes were well tolerated. SPPTC had the potential for pre-operation evaluation and intra-operation navigation of tumors in clinic.

  18. Transferrin-targeted magnetic/fluorescence micelles as a specific bi-functional nanoprobe for imaging liver tumor

    PubMed Central

    2014-01-01

    In order to delineate the location of the tumor both before and during operation, we developed targeted bi-functional polymeric micelles for magnetic resonance (MR) and fluorescence imaging in liver tumors. Hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) were loaded into the polymeric micelles through self-assembly of an amphiphilic block copolymer poly(ethylene glycol)-poly(ϵ-caprolactone). After, transferrin (Tf) and near-infrared fluorescence molecule Cy5.5 were conjugated onto the surface of the polymeric micelles to obtain the nanosized probe SPIO@PEG-b-PCL-Tf/Cy5.5 (SPPTC). Imaging capabilities of this nanoprobe were evaluated both in vitro and in vivo. The accumulation of SPPTC in HepG2 cells increased over SPIO@PEG-b-PCL-Cy5.5 (SPPC) by confocal microscopy. The targeted nanoprobe SPPTC possessed favorable properties on the MR and fluorescence imaging both in vitro and in vivo. The MTT results showed that the nanoprobes were well tolerated. SPPTC had the potential for pre-operation evaluation and intra-operation navigation of tumors in clinic. PMID:25400528

  19. A novel optical nanoprobe for trypsin detection and inhibitor screening based on Mn-doped ZnSe quantum dots.

    PubMed

    Gao, Xue; Tang, Guangchao; Li, Yang; Su, Xingguang

    2012-09-19

    In this paper, a novel optical nanoprobe (Mn:ZnSe d-dots-Arg(6)) for trypsin detection and its inhibitor screening has been constructed successfully based on the fluorescence quenching and recovery of Mn:ZnSe d-dots. Mn:ZnSe d-dots would aggregate in the presence of positively charged Arg(6) (six arginine residues) due to electrostatic interactions that result in the fluorescence quenching. Arg(6) can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the aggregation of Mn:ZnSe d-dots can be prohibited, which lead to the fluorescence recovery. Experimental results show that the recovery in fluorescence intensity is linearly proportional to the concentration of trypsin within the range of 0.1-12.0 μg mL(-1) with a detection limit of 40 ng mL(-1) under the optimized experimental conditions. We also prove the feasibility of fluorescence recovery of Mn:ZnSe d-dots for trypsin detection through the resonance light scattering (RLS) technique. Additionally, the optical nanoprobe can be employed for screening the inhibitors of trypsin. The optical nanoprobe was successfully applied for the determination of trypsin in human serum and urine samples with good accuracy and satisfactory recovery. PMID:22882833

  20. New Insight of Tetraphenylethylene-based Raman Signatures for Targeted SERS Nanoprobe Construction Toward Prostate Cancer Cell Detection.

    PubMed

    Ramya, Adukkadan N; Joseph, Manu M; Nair, Jyothi B; Karunakaran, Varsha; Narayanan, Nisha; Maiti, Kaustabh Kumar

    2016-04-27

    We have designed and synthesized novel tetraphenylethylene (TPE) appended organic fluorogens and unfold their unique Raman fingerprinting reflected by surface-enhanced Raman scattering (SERS) upon adsorption on nanoroughened gold surface as a new insight in addition to their prevalent aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) phenomena. A series of five TPE analogues has been synthesized consisting of different electron donors such as (1) indoline with propyl (TPE-In), (2) indoline with lipoic acid (TPE-In-L), (3) indoline with Boc-protected propyl amine (TPE-In-Boc), (4) benzothaizole (TPE-B), and (5) quinaldine (TPE-Q). Interestingly, all five TPE analogues produced multiplexing Raman signal pattern, out of which TPE-In-Boc showed a significant increase in signal intensity in the fingerprint region. An efficient SERS nanoprobe has been constructed using gold nanoparticles as SERS substrate, and the TPE-In as the Raman reporter, which conjugated with a specific peptide substrate, Cys-Ser-Lys-Leu-Gln-OH, well-known for the recognition of prostate-specific antigen (PSA). The designated nanoprobe TPE-In-PSA@Au acted as SERS "ON/OFF" probe in peace with the vicinity of PSA protease, which distinctly recognizes PSA expression with a limit of detection of 0.5 ng in SERS platform. Furthermore, TPE-In-PSA@Au nanoprobe was efficiently recognized the overexpressed PSA in human LNCaP cells, which can be visualized through SERS spectral analysis and SERS mapping. PMID:27049934

  1. Detectability of Gravitational Waves from High-Redshift Binaries

    NASA Astrophysics Data System (ADS)

    Rosado, Pablo A.; Lasky, Paul D.; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-01

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳1010M⊙ can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

  2. Detectability of Gravitational Waves from High-Redshift Binaries.

    PubMed

    Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-11

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms. PMID:27015470

  3. Search for Binary Trojans

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Grundy, W. M.; Ryan, E. L.; Benecchi, S. D.

    2015-11-01

    We have reexamined 41 Trojan asteroids observed with the Hubble Space Telescope (HST) to search for unresolved binaries. We have identified one candidate binary with a separation of 53 milliarcsec, about the width of the diffraction limited point-spread function (PSF). Sub-resolution-element detection of binaries is possible with HST because of the high signal-to-noise ratio of the observations and the stability of the PSF. Identification and confirmation of binary Trojans is important because a Trojan Tour is one of five possible New Frontiers missions. A binary could constitute a potentially high value target because of the opportunity to study two objects and to test models of the primordial nature of binaries. The potential to derive mass-based physical information from the binary orbit could yield more clues to the origin of Trojans.

  4. Self-assembled mPEG-PCL-g-PEI micelles for multifunctional nanoprobes of doxorubicin delivery and magnetic resonance imaging and optical imaging.

    PubMed

    Guo, Qingfa; Kuang, Lei; Cao, Hui; Li, Weizhong; Wei, Jing

    2015-12-01

    In this paper, a novel bifunctional nanoprobe based on polyethylene glycol(MPEG)-poly(ϵ-caprolactone)(ϵ-CL)-polyethylenimine(PEI) labeled with FITC (MPEG-PCL-PEI-FITC, PCIF) were prepared to provide tumor therapy and simultaneous diagnostic information via magnetic resonance imaging (MRI) and optical imaging. Superparamagnetic iron oxide (SPIO) and doxorubicin (DOX) loaded PCIF (PCIF/SPIO/DOX) nanoprobes were prepared by self-assembling into micelles, which had uniformly distributed particle size of 130 ± 5 nm and a zeta potential of +35 ± 2 mV. Transmission electronic microscopy(TEM) showed that SPIO NPs were loaded into PCIF micelles. The PCIF/SPIO/DOX nanoprobes were superparamagnetic at 300 K with saturated magnetization of 20.5 emu/g Fe by vibrating-sample-magnetomete (VSM). Studies on cellular uptake of PCIF/SPIO/DOX nanoprobes demonstrated that SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI were simultaneously taken up by the breast cancer (4T1) cells. After intravenous injection of PCIF/SPIO/DOX nanoprobes in 4T1 tumor-bearing mice, SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI micelles were simultaneously delivered into tumor tissue by histochemisty. This work is important for the applications to multimodal diagnostic and theragnosis as nanomedicine. PMID:26513751

  5. PHOEBE: PHysics Of Eclipsing BinariEs

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick

    2011-06-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability.

  6. DNA-templated assembly of a heterobivalent quantum dot nanoprobe for extra- and intracellular dual-targeting and imaging of live cancer cells.

    PubMed

    Wei, Wei; He, Xuewen; Ma, Nan

    2014-05-26

    Quantum dots (QDs) hold great promise for the molecular imaging of cancer because of their superior optical properties. Although cell-surface biomarkers can be readily imaged with QDs, non-invasive live-cell imaging of critical intracellular cancer markers with QDs is a great challenge because of the difficulties in the automatic delivery of QD probes to the cytosol and the ambiguity of intracellular targeting signals. Herein, we report a new type of DNA-templated heterobivalent QD nanoprobes with the ability to target and image two spatially isolated cancer markers (nucleolin and mRNA) present on the cell surface and in the cell cytosol. Bypassing endolysosomal sequestration, this type of QD nanoprobes undergo macropinocytosis following the nucleolin targeting and then translocate to the cytosol for mRNA targeting. Fluorescence resonance energy transfer (FRET) based confocal microscopy enables unambiguous signal deconvolution of mRNA-targeted QD nanoprobes inside cancer cells. PMID:24740625

  7. Imaging PEG-like nanoprobes in tumor, transient ischemia, and inflammatory disease models.

    PubMed

    Wilks, Moses Q; Normandin, Marc D; Yuan, Hushan; Cho, Hoonsung; Guo, Yanyan; Herisson, Fanny; Ayata, Cenk; Wooten, Dustin W; El Fakhri, Georges; Josephson, Lee

    2015-06-17

    The iron chelator deferoxamine (DFO), approved for the treatment of iron overload, has been examined as a therapeutic in a variety of conditions which iron may exacerbate. To evaluate the potential of DFO-bearing PEG-like nanoprobes (DFO-PNs) as therapeutics, we determined their pharmacokinetics (PK) in normal mice, and imaged their accumulation in a tumor model and in models of transient brain ischemia and inflammation. DFO-PNs consist of a DFO, a Cy5.5, and PEG (5 kDa or 30 kDa) attached to Lys-Cys scaffold. Tumor uptake of a [(89)Zr]:DFO-PN(10) (30 kDa PEG, diameter 10 nm) was imaged by PET, surface fluorescence, and fluorescence microscopy. DFO-PN(10) was internalized by tumor cells (fluorescence microscopy) and by cultured cells (by FACS). [(89)Zr]:DFO-PN(4.3) (5 kDa PEG, diameter 4.3 nm) concentrated at incision generated inflammations but not at sites of transient brain ischemia. DFO-PNs are fluorescent, PK tunable forms of DFO that might be investigated as antitumor or anti-inflammatory agents. PMID:25971846

  8. Bifunctional electro-optical nanoprobe to real-time detect local biochemical processes in single cells.

    PubMed

    Zheng, Xin Ting; Hu, Weihua; Wang, Houxiao; Yang, Hongbin; Zhou, Wei; Li, Chang Ming

    2011-07-15

    A bifunctional electro-optical nanoprobe with integrated nanoring electrode and optical nanotip was fabricated and investigated to simultaneously detect both electrical and optical signals in real-time with high spatial resolution. Concurrent measurements of the oxidant generation and the intracellular antioxidant levels in single cells correlate the stronger oxidant generation with an altered initial antioxidant response in the breast cancer cells in comparison to the normal ones suggesting that the cell malignancy is associated with the strength of oxidative stress, and the higher antioxidant level may be the cause of the drug resistance. While the optical detection indicates the fluctuation of the intracellular redox homeostasis, the chronoamperometric signals allow quantitative real-time detection of the H₂O₂ release and decay. Furthermore, the nanoscale probe enables localized simultaneous detections thus discovering that activated enzymes responsible for the oxidative stress target at specific membrane regions. This method promises applications in study of the dynamics of important physiological processes, and provides the opportunity to unravel the interplay of various signaling pathways. PMID:21632233

  9. Fabrication and biological imaging application of AIE-active luminescent starch based nanoprobes.

    PubMed

    Liu, Meiying; Huang, Hongye; Wang, Ke; Xu, Dazhuang; Wan, Qing; Tian, Jianwen; Huang, Qiang; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2016-05-20

    Fabrication of water dispersible, biocompatible and ultrabright luminescent polymeric nanoprobes (LPNs) has been the subject of great research interest. Although a number of LPNs have been fabricated previously through different strategies, the preparation of luminescent carbohydrate polymers with aggregation-induced emission (AIE) characterstic has received only limited attention. In this work, we reported for the first time that AIE-active luminescent starch can be facilely fabricated via mixing the aldehyde-contained AIE dye 4-(1,2,2-triphenylvinyl) benzaldehyde (TPE-CHO) with carboxyl methyl starch sodium (CMS) and amino phenylboronic acid in a one-pot procedure, in which aminophenylboronic acid can serve as the linkage for conjugation of TPE-CHO and CMS. The final products (TPE-CMS LPNs) were characterized by a number of characterization techniques such as (1)H nuclear magnetic resonance spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and fluorescence Spectroscopy in detail. To examine their biomedical application potential, the biocompatibility as well as cell uptake behavior of TPE-CMS LPNs were further determined. We demonstrated that TPE-CMS LPNs showed high water dispersibility and strong fluorescence, well biocompatibility and efficient cell internalization behavior, making them promising candidates for various biomedical applications. PMID:26917371

  10. Design for an X-ray Nanoprobe Prototype with a Sub-10-nm Positioning Requirement

    NASA Astrophysics Data System (ADS)

    Shu, D.; Maser, J.; Lai, B.; Vogt, S.

    2004-05-01

    We are developing a new hard x-ray nanoprobe beamline with 30 nm resolution at the Advanced Photon Source (APS). Imaging and spectroscopy at this resolution level require staging of x-ray optics and specimens with a mechanical repeatability of better than 10 nm. We have developed a prototype instrument with a novel interferometrically controlled scanning stage system. The system consists of nine DC-motor-driven stages, four picomotor-driven stages, and two PZT-driven stages. An APS-designed custom-built laser Doppler displacement meter system provides two-dimensional differential displacement measurement with subnanometer resolution between the zone-plate x-ray optics and the sample holder. Also included is the alignment and stable positioning of two stacked zone plates for increasing the focusing efficiency. The entire scanning system was designed with high stiffness, high repeatability, low drift, flexible scanning schemes, and possibility of fast feedback for differential motion. Designs of the scanning stage system, as well as preliminary mechanical test results, are presented in this paper.

  11. In situ deposition of Prussian blue on mesoporous carbon nanosphere for sensitive electrochemical immunoassay.

    PubMed

    Lai, Guosong; Zhang, Haili; Yu, Aimin; Ju, Huangxian

    2015-12-15

    A Prussian blue (PB) functionalized mesoporous carbon nanosphere (MCN) composite was prepared for loading signal antibody and high-content glucose oxidase (GOD) to obtain a new nanoprobe for sensitive electrochemical immunoassay. The MCN nanocarrier with an average diameter of 180 nm was synthesized by using mesoporous silica nanosphere as a hard template in combination with a hydrothermal carbonization method. This hydrophilic carbon nanomaterial provided an ideal platform for in situ deposition of high-content PB to form the MCN-PB nanocomposite. Based on the step-wise assembly of polyelectrolyte and gold nanoparticles (Au NPs) on the negative-charged nanocomposite, signal antibody and high-content GOD were loaded on this nanocarrier to obtain the nanoprobe. After a sandwich immunoreaction at an Au NPs-modified screen-printed carbon electrode based immunosensor, the nanoprobes were quantitatively captured on the electrode surface to produce sensitive electrochemical response with a PB-mediated GOD catalytic reaction for immunoassay. The high loading of PB and GOD on the nanoprobe greatly amplified the electrochemical signal, leading to the development of a new immunoassay method with high sensitivity. Using human immunoglobulin G as a model analyte, excellent analytical performance including a wide linear range from 0.01 to 100 ng/mL and a low detection limit down to 7.8 pg/mL was obtained. Additionally, the immunosensor showed high specificity, satisfactory stability and repeatability as well as acceptable reliability. The PB-mediated GOD electrochemical system well excluded the conventional interference from the dissolved oxygen. Thus this immunoassay method provides great potentials for practical applications. PMID:26201983

  12. Case A Binary Evolution

    SciTech Connect

    Nelson, C A; Eggleton, P P

    2001-03-28

    We undertake a comparison of observed Algol-type binaries with a library of computed Case A binary evolution tracks. The library consists of 5500 binary tracks with various values of initial primary mass M{sub 10}, mass ratio q{sub 0}, and period P{sub 0}, designed to sample the phase-space of Case A binaries in the range -0.10 {le} log M{sub 10} {le} 1.7. Each binary is evolved using a standard code with the assumption that both total mass and orbital angular momentum are conserved. This code follows the evolution of both stars until the point where contact or reverse mass transfer occurs. The resulting binary tracks show a rich variety of behavior which we sort into several subclasses of Case A and Case B. We present the results of this classification, the final mass ratio and the fraction of time spent in Roche Lobe overflow for each binary system. The conservative assumption under which we created this library is expected to hold for a broad range of binaries, where both components have spectra in the range G0 to B1 and luminosity class III - V. We gather a list of relatively well-determined observed hot Algol-type binaries meeting this criterion, as well as a list of cooler Algol-type binaries where we expect significant dynamo-driven mass loss and angular momentum loss. We fit each observed binary to our library of tracks using a {chi}{sup 2}-minimizing procedure. We find that the hot Algols display overall acceptable {chi}{sup 2}, confirming the conservative assumption, while the cool Algols show much less acceptable {chi}{sup 2} suggesting the need for more free parameters, such as mass and angular momentum loss.

  13. An Nd3+-sensitized upconversion nanophosphor modified with a cyanine dye for the ratiometric upconversion luminescence bioimaging of hypochlorite

    NASA Astrophysics Data System (ADS)

    Zou, Xianmei; Liu, Yi; Zhu, Xingjun; Chen, Min; Yao, Liming; Feng, Wei; Li, Fuyou

    2015-02-01

    Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in vivo. The excitation laser efficiently reduced the heating effect, compared to the commonly used 980 nm laser for upconversion systems.Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in

  14. Erythrocyte-derived nano-probes functionalized with antibodies for targeted near infrared fluorescence imaging of cancer cells

    PubMed Central

    Mac, Jenny T.; Nuñez, Vicente; Burns, Joshua M.; Guerrero, Yadir A.; Vullev, Valentine I.; Anvari, Bahman

    2016-01-01

    Constructs derived from mammalian cells are emerging as a new generation of nano-scale platforms for clinical imaging applications. Herein, we report successful engineering of hybrid nano-structures composed of erythrocyte-derived membranes doped with FDA-approved near infrared (NIR) chromophore, indocyanine green (ICG), and surface-functionalized with antibodies to achieve molecular targeting. We demonstrate that these constructs can be used for targeted imaging of cancer cells in vitro. These erythrocyte-derived optical nano-probes may provide a potential platform for clinical translation, and enable molecular imaging of cancer biomarkers. PMID:27446657

  15. Preliminary design of a zone plate based hard X-ray monochromatic diffraction nanoprobe for materials studies at APS

    NASA Astrophysics Data System (ADS)

    Cai, Zhonghou; Liu, Wenjun; Tischler, Jonathan Z.; Shu, Deming; Xu, Ruqing; Schmidt, Oliver

    2013-09-01

    Aiming at studies of the micro/nano-structures of a broad range materials and electronic devices, Advance Photon Source (APS) is developing a dedicated diffraction nanoprobe (DNP) beamline for the needs arising from a multidiscipline research community. As a part of the APS Upgrade Project, the planed facility, named Sub-micron 3-D Diffraction (S3DD) beamline1, integrates the K-B mirror based polychromatic Laue diffraction and the Fresnel zone-plate based monochromatic diffraction techniques that currently support 3D/2D microdiffraction programs at the 34-ID-E and 2-ID-D of the APS, respectively. Both diffraction nanoprobes are designed to have a 50-nm or better special resolution. The zone-plate based monochromatic DNP has been preliminarily designed and will be constructed at the sector 34-ID. It uses an APS-3.0-cm period or APS-3.3-cm period undulator, a liquid-nitrogen cooled mirror as its first optics, and a water cooled small gap silicon double-crystal monochromator with an energy range of 5-30 keV. A set of zone plates have been designed to optimize for focusing efficiency and the working distance based on the attainable beamline length and the beam coherence. To ensure the nanoprobe performance, high stiffness and high precision flexure stage systems have been designed or demonstrated for optics mounting and sample scanning, and high precision temperature control of the experimental station will be implemented to reduce thermal instability. Designed nanoprobe beamline has a good management on thermal power loading on optical components and allows high degree of the preservation of beam brilliance for high focal flux and coherence. Integrated with variety of X-ray techniques, planed facility provides nano-XRD capability with the maximum reciprocal space accessibility and allows micro/nano-spectroscopy studies with K-edge electron binding energies of most elements down to Vanadium in the periodic table. We will discuss the preliminary design of the zone

  16. Detecting De-gelation through Tissue Using Magnetically Modulated Optical Nanoprobes (MagMOONs)

    PubMed Central

    Nguyen, KhanhVan T.; Anker, Jeffrey N.

    2014-01-01

    Alginate gels are widely used for drug delivery and implanted devices. The rate at which these gels break down is important for controlling drug release. Since the de-gelation may be different in vivo, monitoring this process in situ is essential. However, it is challenging to monitor the gel through tissue due to optical scattering and tissue autofluorescence. Herein we describe a method to detect through tissue the chemically-induced changes in viscosity and de-gelation process of alginate gels using magnetically modulated optical nanoprobes (MagMOONs). The MagMOONs are fluorescent magnetic microspheres coated with a thin layer of opaque metal on one hemisphere. The metal layer prevents excitation and emission light from passing through one side of the MagMOONs, which creates orientation-dependent fluorescence intensity. The magnetic particles also align in an external magnetic field and give blinking signals when they rotate to follow an external modulated magnetic field. The blinking signals from these MagMOONs are distinguished from background autofluorescence and can be tracked on a single particle level in the absence of tissue, or for an ensemble average of particles blinking through tissue. When these MagMOONs are dispersed in calcium alginate gel, they become sensors for detecting gel degradation upon addition of either ammonium ion or alginate lyase. Our results show MagMOONs start blinking approximately 10 minutes after 2 mg/mL alginate lyase addition and this blinking is clearly detected even through up to 4 mm chicken breast. This approach can potentially be employed to detect bacterial biofilm formation on medical implants by sensing specific proteases that either activate a related function or regulate biofilm formation. It can also be applied to other biosensors and drug delivery systems based on enzyme-catalyzed breakdown of gel components. PMID:26273129

  17. Nanoscopium: a Scanning Hard X-ray Nanoprobe Beamline at Synchrotron Soleil

    NASA Astrophysics Data System (ADS)

    Somogyi, A.; Polack, F.; Moreno, T.

    2010-06-01

    Nanoscopium is the single scanning hard X-ray nano-probe beamline planned at SOLEIL. This ˜155 m long beamline will fully exploit the high brilliance and coherence characteristics of the X-ray beam both for diffraction limited focusing and for contrast formation. It will offer the most advanced imaging techniques in multimodal mode and will be a research tool for a wide user community working in the fields of earth-, environmental-, and life-sciences. The different μ-μnano-probe techniques offered by the beamline will permit elemental mapping at trace (ppm) levels (scanning XRF), speciation mapping (XANES), phase gradient mapping (scanning differential phase contrast), and density-contrast based imaging of internal structures (coherent diffraction imaging) in the 30 nm to 1 μm spatial resolution range, also in "in situ conditions". Nanoscopium will cover the 5-20 keV energy range. The stability of the nanobeam will be ensured by horizontally reflecting beamline optics (a sagitally and a tangentially pre-focusing mirror, horizontally reflecting monochromators) in front of the overfilled secondary source. Trade-off between high energy resolution (ΔE/E˜10-4) and high flux (1011 ph/s with ΔE/E˜10-2) will be achieved by two interchangeable monochromators (a double crystal and a double multilayer one). KB mirror and FZP lenses will be used as focusing devices. The beamline is in the design and construction phase. It is foreseen to be open for users at the beginning of 2013.

  18. Rearranging a nanoprobe: Line foci, grid shadow patterns and performance tests

    NASA Astrophysics Data System (ADS)

    Rothermel, Martin; Butz, Tilman; Reinert, Tilo

    2009-06-01

    After a major modification of the target chamber at the Leipzig high energy ion nanoprobe the probe forming lens system, consisting of two separated quadrupole doublets, had been carefully realigned. This was done by adjusting the line foci position of each individual quadrupole on the centre position defined by the unfocused beam. Using a high magnification microscope the alignment process is very effective and precise. The lens system could be precisely realigned except an intrinsic rotational misalignment which is essentially reduced by a correction lens. Grid shadow patterns have been taken and analysed in order to assess the characteristics of the system. The dominant aberrations are spherical with an additional parasitic octupole. The grid shadow method is also very useful to determine the best position of the aperture diaphragms which minimizes the influence of the aberrations onto the beam spot size. The rearrangement allowed larger aperture diaphragms for higher beam currents at a moderate increase in beam spot sizes. Performance tests yielded proton microbeam currents and half-widths of 4.5 nA at 1.5 μm, 8.3 nA at 1.5 μm and 17.2 nA at 2 μm. For high resolution work the expected beam spots around 0.3 μm at 100 pA were not achieved. The reason is very likely interference on the beam scanner, correlated in x- and y-direction, which results from the insufficiently rectified power supply voltage of the transconductance amplifier.

  19. Merging compact binaries in hierarchical triple systems: Resonant excitation of binary eccentricity

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Lai, Dong; Yuan, Ye-Fei

    2015-12-01

    We study the secular dynamics of compact binaries (consisting of white dwarfs, neutron stars or black holes) with tertiary companions in hierarchical triple systems. As the inner binary (with initially negligible eccentricity) undergoes orbital decay due to gravitational radiation, its eccentricity can be excited by gravitational forcing from the tertiary. This excitation occurs when the triple system passes through an "apsidal precession resonance," when the precession rate of the inner binary, driven by the gravitational perturbation of the external companion and general relativity, matches the precession rate of the outer binary. The eccentricity excitation requires the outer companion to be on an eccentric orbit, with the mutual inclination between the inner and outer orbits less than ˜40 ° . Gravitational wave (GW) signals from the inner binary can be significantly modified as the system evolves through the apsidal precession resonance. For some system parameters (e.g., a white dwarf binary with a brown dwarf tertiary), the resonance can happen when the binary emits GWs in the 10-4-10-1 Hz range (the sensitivity band of LISA).

  20. Template bank for gravitational waveforms from coalescing binary black holes: Nonspinning binaries

    SciTech Connect

    Ajith, P.; Hewitson, M.; Babak, S.; Chen, Y.; Krishnan, B.; Whelan, J. T.; Dorband, N.; Pollney, D.; Rezzolla, L.; Sintes, A. M.; Bruegmann, B.; Hannam, M.; Husa, S.; Sperhake, U.; Diener, P.; Gonzalez, J.; Santamaria, L.; Thornburg, J.

    2008-05-15

    Gravitational waveforms from the inspiral and ring-down stages of the binary black-hole coalescences can be modeled accurately by approximation/perturbation techniques in general relativity. Recent progress in numerical relativity has enabled us to model also the nonperturbative merger phase of the binary black-hole coalescence problem. This enables us to coherently search for all three stages of the coalescence of nonspinning binary black holes using a single template bank. Taking our motivation from these results, we propose a family of template waveforms which can model the inspiral, merger, and ring-down stages of the coalescence of nonspinning binary black holes that follow quasicircular inspiral. This two-dimensional template family is explicitly parametrized by the physical parameters of the binary. We show that the template family is not only effectual in detecting the signals from black-hole coalescences, but also faithful in estimating the parameters of the binary. We compare the sensitivity of a search (in the context of different ground-based interferometers) using all three stages of the black-hole coalescence with other template-based searches which look for individual stages separately. We find that the proposed search is significantly more sensitive than other template-based searches for a substantial mass range, potentially bringing about remarkable improvement in the event rate of ground-based interferometers. As part of this work, we also prescribe a general procedure to construct interpolated template banks using nonspinning black-hole waveforms produced by numerical relativity.

  1. Predicting binary merger event rates for advanced LIGO/Virgo

    NASA Astrophysics Data System (ADS)

    Holz, Daniel; Belczynski, Chris; O'Shaughnessy, Richard; Bulik, Tomek; LIGO Collaboration

    2016-03-01

    We discuss estimates of the rates of mergers of binary systems composed of neutron stars and/or stellar mass black holes. We use the StarTrack population synthesis code, and make predictions for the detection rate of compact binary coalescences with the advanced LIGO/Virgo gravitational wave detectors. Because these instruments are sensitive to massive (M > 20M⊙) stellar-mass binary black holes mergers out to high redshift (z > 1), we discuss the cosmological effects which must be taken into account when calculating LIGO detection rates, including a generalization of the calculation of the ``peanut factor'' and the sensitive time-volume.

  2. Facile preparation and biological imaging of luminescent polymeric nanoprobes with aggregation-induced emission characteristics through Michael addition reaction.

    PubMed

    Lv, Qiulan; Wang, Ke; Xu, Dazhuang; Liu, Meiying; Wan, Qing; Huang, Hongye; Liang, Shangdong; Zhang, Xiaoyong; Wei, Yen

    2016-09-01

    Water dispersion aggregation-induced emission (AIE) dyes based nanomaterials have recently attracted increasing attention in the biomedical fields because of their unique optical properties, outstanding performance as imaging and therapeutic agents. The methods to conjugate hydrophilic polymers with AIE dyes to solve the hydrophobic nature of AIE dyes and makeS them widely used in biomedicine, which have been extensively explored and paid great effort previously. Although great advance has been made in the fabrication and biomedical applications of AIE-active polymeric nanoprobes, facile and efficient strategies for fabrication of biodegradable AIE-active nanoprobes are still high desirable. In this work, amphiphilic biodegradable fluorescent organic nanoparticles (PLL-TPE-O-E FONs) have been fabricated for the first time by conjugation of AIE dye tetraphenylethene acrylate (TPE-O-E) with Poly-l-Lysine (PLL) through a facile one-step Michael addition reaction, which was carried out under rather mild conditions, included air atmosphere, near room temperature and absent of metal catalysts or hazardous reagents. Due to the unique AIE properties, these amphiphilic copolymers tend to self-assemble into high luminescent water dispersible nanoparticles with size range from 400 to 600nm. Laser scanning microscope and cytotoxicity results revealed that PLL-TPE-O-E FONs can be internalized into cytoplasm with negative cytotoxicity, which implied that PLL-TPE-O-E FONs are promising for biological applications. PMID:27311129

  3. Analytical Study of BAM (Al/GaAs) and Photovoltaic Samples Using State-of-The-Art Auger Nanoprobes

    SciTech Connect

    Yadav, P.; Bouttemy, M.; Vigneron, J.; Etcheberry, A.; Martinez, E.; Renault, O.; Mur, P.; Chabli, A.; Munoz, D.

    2011-11-10

    For the analysis of certified semiconducting Al{sub 0.7}Ga{sub 0.3}As/GaAs superlattices and photovoltaic samples, we used new generations Auger nano-probes such as the JEOL JAMP-9500F Field emission Microprobe and the PHI-700 Xi system. These nano-probes are generally used for the chemical analysis of complex nano-structures at the deca-nanometric scale. In this paper, we first used both systems for the determination of the surface composition of an Al{sub 0.7}Ga{sub 0.3}As/GaAs reference sample. In that, we studied the impact of surface topography on the Auger analysis. Secondly, we used both systems for chemical analysis of photovoltaic samples. Here, we investigated the in-depth chemical composition, in particular the a-Si:H (n)/ZnO/Al and ITO/a-Si:H (p) interfaces, after a specific cross-section preparation. However, limitations such as image drift due to acoustic vibration and heating effects due to continuous bombardment of energetic electrons at the same point are still a big challenge for quick, routine analysis.

  4. Analytical Study of BAM (Al/GaAs) and Photovoltaic Samples Using State-of-The-Art Auger Nanoprobes

    NASA Astrophysics Data System (ADS)

    Yadav, P.; Bouttemy, M.; Martinez, E.; Vigneron, J.; Renault, O.; Mur, P.; Munoz, D.; Etcheberry, A.; Chabli, A.

    2011-11-01

    For the analysis of certified semiconducting Al0.7Ga0.3As/GaAs superlattices and photovoltaic samples, we used new generations Auger nano-probes such as the JEOL JAMP-9500F Field emission Microprobe and the PHI-700 Xi system. These nano-probes are generally used for the chemical analysis of complex nano-structures at the deca-nanometric scale. In this paper, we first used both systems for the determination of the surface composition of an Al0.7Ga0.3As/GaAs reference sample. In that, we studied the impact of surface topography on the Auger analysis. Secondly, we used both systems for chemical analysis of photovoltaic samples. Here, we investigated the in-depth chemical composition, in particular the a-Si:H (n)/ZnO/Al and ITO/a-Si:H (p) interfaces, after a specific cross-section preparation. However, limitations such as image drift due to acoustic vibration and heating effects due to continuous bombardment of energetic electrons at the same point are still a big challenge for quick, routine analysis.

  5. Application prospective of nanoprobes with MRI and FI dual-modality imaging on breast cancer stem cells in tumor.

    PubMed

    Chen, Hetao; Wang, Yu; Wang, Tong; Shi, Dongxing; Sun, Zengrong; Xia, Chunhui; Wang, Baiqi

    2016-01-01

    Breast cancer (BC) is a serious disease to threat lives of women. Numerous studies have proved that BC originates from cancer stem cells (CSCs). But at present, no one approach can quickly and simply identify breast cancer stem cells (BCSCs) in solid tumor. Nanotechnology is probably able to realize this goal. But in study process, scientists find it seems that nanomaterials with one modality, such as magnetic resonance imaging (MRI) or fluorescence imaging (FI), have their own advantages and drawbacks. They cannot meet practical requirements in clinic. The nanoprobe combined MRI with FI modality is a promising tool to accurately detect desired cells with low amount in tissue. In this work, we briefly describe the MRI and FI development history, analyze advantages and disadvantages of nanomaterials with single modality in cancer cell detection. Then the application development of nanomaterials with dual-modality in cancer field is discussed. Finally, the obstacles and prospective of dual-modal nanoparticles in detection field of BCSCs are also pointed out in order to speed up clinical applications of nanoprobes. PMID:27339420

  6. Persistent luminescence nanoprobe for biosensing and lifetime imaging of cell apoptosis via time-resolved fluorescence resonance energy transfer.

    PubMed

    Zhang, Lei; Lei, Jianping; Liu, Jintong; Ma, Fengjiao; Ju, Huangxian

    2015-10-01

    Time-resolved fluorescence technique can reduce the short-lived background luminescence and auto-fluorescence interference from cells and tissues by exerting the delay time between pulsed excitation light and signal acquisition. Here, we prepared persistent luminescence nanoparticles (PLNPs) to design a universal time-resolved fluorescence resonance energy transfer (TR-FRET) platform for biosensing, lifetime imaging of cell apoptosis and in situ lifetime quantification of intracellular caspase-3. Three kinds of PLNPs-based nanoprobes are assembled by covalently binding dye-labeled peptides or DNA to carboxyl-functionalized PLNPs for the efficient detection of caspase-3, microRNA and protein. The peptides-functionalized nanoprobe is also employed for fluorescence lifetime imaging to monitor cell apoptosis, which shows a dependence of cellular fluorescence lifetime on caspase-3 activity and thus leads to an in situ quantification method. This work provides a proof-of-concept for PLNPs-based TR-FRET analysis and demonstrates its potential in exploring dynamical information of life process. PMID:26232881

  7. Patterned forest-assembly of single-wall carbon nanotubes and carbon nanotube atomic force microscopy nanoprobes

    NASA Astrophysics Data System (ADS)

    Wei, Haoyan

    Single-wall carbon nanotubes (SWNTs) are envisioned to greatly impact future science and technology particularly in the nanoscale range due to their unique one dimensional structure with tunable electrical conductivity. Thus they have received considerable attention in the development of nanodevices, field emitters and biosensors. The ability to place carbon nanotubes (CNTs) with controlled orientation at desired sites presents one major challenge in assembling these remarkable nanostructures into useful functional devices. In this dissertation a metal-assisted self-assembly technique was utilized in which dense rope-lattice-like SWNT forests with upright direction were obtained by immobilizing carboxylated nanotubes from dimethylformamide (DMF) nonaqueous media onto the underlying substrates with the linkage of FeO(OH)/FeOCl crystallites. In comparison with growing CNTs by chemical vapor deposition (CVD) on patterned catalyst pads, this self-assembly approach can take advantage of post-synthesis SWNT separation according to length and type (met allic versus semiconducting). Since FeO(OH)/FeOCl crystallites acted as linkers to bridge CNTs onto the substrates, the appropriate placement of these iron deposits was pivotal to realize the desired SWNT patterns. To assist in localizing these FeO(OH)/FeOCl crystallites, three approaches on diverse substrates including Nafion, Si/SiO x and Au were investigated with the aid of low-energy electron-beam direct writing (on Nafion and Si/SiOx) and photolithography (on Au) by creating preferential precipitation sites for FeO(OH)/FeOCl crystallites. Such differential deposition of FeO(OH)/FeOCl crystallites provided the basis for the patterned site-specific self-assembly of SWNT forests as demonstrated by atomic force microscopy (AFM) and resonance Raman spectroscopy. A second part of this dissertation resulted in CNT nanoprobes on conductive AFM probes fabricated with the help of a positive dielectrophoretic (DEP) process. Under

  8. In Vivo Immunotoxicity of SiO2@(Y0.5Gd0.45Eu0.05)2O3 as Dual-Modality Nanoprobes

    PubMed Central

    Tian, Xiumei; Li, Ermao; Yang, Fanwen; Peng, Ye; Zhu, Jixiang; He, Fupo; Chen, Xiaoming

    2014-01-01

    We have successfully synthesized SiO2@(Y0.5Gd0.45Eu0.05)2O3 nanocomposites as a potential dual-modality nanoprobe for molecular imaging in vitro. However, their immunotoxicity assessment in vivo remains unknown. In this article, the in vitro biocompatibility of our dual-modality nanoprobes was assayed in terms of cell viability and apoptosis. In vivo immunotoxicity was investigated by monitoring the generation of reactive oxygen species (ROS), cluster of differentiation (CD) markers and cytokines in Balb/c mice. The data show that the in vitro biocompatibility was satisfactory. In addition, the immunotoxicity data revealed there are no significant changes in the expression levels of CD11b and CD71 between the nanoprobe group and the Gd in a diethylenetriaminepentaacetic acid (DTPA) chelator (Gd-DTPA) group 24 h after injection in Balb/c mice (p > 0.05). Importantly, there are significant differences in the expression levels of CD206 and CD25 as well as the secretion of IL-4 and the generation of ROS 24 h after injection (p < 0.05). Transmission electron microscopy (TEM) images showed that few nanoprobes were localized in the phagosomes of liver and lung. In conclusion, the toxic effects of our nanoprobes may mainly result from the aggregation of particles in phagosomes. This accumulation may damage the microstructure of the cells and generate oxidative stress reactions that further stimulate the immune response. Therefore, it is important to evaluate the in vivo immunotoxicity of these rare earth-based biomaterials at the molecular level before molecular imaging in vivo. PMID:25105724

  9. Binary synchronous simulator

    NASA Technical Reports Server (NTRS)

    Rogers, J. R., III

    1980-01-01

    Flexible simulator for trouble-shooting data transmission system uses binary synchronous communications protocol to produce error-free transmission of data between two points. Protocol may be used to replace display generator or be directly fed to display generator.

  10. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  11. Binary pattern deflectometry.

    PubMed

    Butel, Guillaume P; Smith, Greg A; Burge, James H

    2014-02-10

    Deflectometry is widely used to accurately calculate the slopes of any specular reflective surface, ranging from car bodies to nanometer-level mirrors. This paper presents a new deflectometry technique using binary patterns of increasing frequency to retrieve the surface slopes. Binary Pattern Deflectometry allows almost instant, simple, and accurate slope retrieval, which is required for applications using mobile devices. The paper details the theory of this deflectometry method and the challenges of its implementation. Furthermore, the binary pattern method can also be combined with a classic phase-shifting method to eliminate the need of a complex unwrapping algorithm and retrieve the absolute phase, especially in cases like segmented optics, where spatial algorithms have difficulties. Finally, whether it is used as a stand-alone or combined with phase-shifting, the binary patterns can, within seconds, calculate the slopes of any specular reflective surface. PMID:24663273

  12. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  13. Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Batten, A.; Murdin, P.

    2000-11-01

    Historically, spectroscopic binary stars were binary systems whose nature was discovered by the changing DOPPLER EFFECT or shift of the spectral lines of one or both of the component stars. The observed Doppler shift is a combination of that produced by the constant RADIAL VELOCITY (i.e. line-of-sight velocity) of the center of mass of the whole system, and the variable shift resulting from the o...

  14. Binary-Symmetry Detection

    NASA Technical Reports Server (NTRS)

    Lopez, Hiram

    1987-01-01

    Transmission errors for zeros and ones tabulated separately. Binary-symmetry detector employs psuedo-random data pattern used as test message coming through channel. Message then modulo-2 added to locally generated and synchronized version of test data pattern in same manner found in manufactured test sets of today. Binary symmetrical channel shows nearly 50-percent ones to 50-percent zeroes correspondence. Degree of asymmetry represents imbalances due to either modulation, transmission, or demodulation processes of system when perturbed by noise.

  15. Direct Exoplanet Detection with Binary Differential Imaging

    NASA Astrophysics Data System (ADS)

    Rodigas, Timothy J.; Weinberger, Alycia; Mamajek, Eric E.; Males, Jared R.; Close, Laird M.; Morzinski, Katie; Hinz, Philip M.; Kaib, Nathan

    2015-10-01

    Binaries are typically excluded from direct imaging exoplanet surveys. However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems. Here, we suggest that visual binaries offer unique advantages for direct imaging. We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at a high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star. We demonstrate this by observing a young visual binary separated by 4″ with MagAO/Clio-2 at 3.9 μm, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright. Comparing BDI to angular differential imaging (ADI), we find that BDI’s 5σ contrast is ˜0.5 mag better than ADI’s within ˜1″ for the particular binary we observed. Because planets typically reside close to their host stars, BDI is a promising technique for discovering exoplanets in stellar systems that are often ignored. BDI is also 2-4× more efficient than ADI and classical reference PSF subtraction, since planets can be detected around both the target and PSF reference simultaneously. We are currently exploiting this technique in a new MagAO survey for giant planets in 140 young nearby visual binaries. BDI on a space-based telescope would not be limited by isoplanatism effects and would therefore be an even more powerful tool for imaging and discovering planets. This paper includes data obtained at the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  16. Assessment of the nature interactions of β-amyloid protein by a nanoprobe method.

    PubMed

    Caballero, Leonardo; Mena, Juan; Morales-Alvarez, Aurora; Kogan, Marcelo J; Melo, Francisco

    2015-01-01

    We present a method based on atomic force microscopy (AFM) to assess the work of adhesion between the interfaces of gold AFM tips functionalized with three peptides derived from β-sheet breaker LPFFD [CLPFFD-NH2 (i0) and their isomers CDLPFF-NH2 (i1) and CLPDFF-NH2 (i2)], and the beta-amyloid protein (Aβ1-42). β-Amyloid protein was deposited onto a highly oriented graphite (HOPG) surface as protofibrils and fibrils. The presence of the residues Leu (L), Phe (F), and Phe (F), which are also present in the native sequence, confirm that the peptides are able to bind to the aggregates of Aβ1-42 fibrils and protofibrils. Force of adhesion data were directly obtained from the maximum force on retraction, and the work of adhesion was calculated from the Jhonson-Kendall-Roberts model (JKR-Model). Both the polar and dispersive contributions to the surface energy of the peptides i0, i1, and i2, as well as Aβ1-42 fibrils and protofibrils, were determined by means of measuring the contact angle and using the two-fluid method. The macroscopic energies of the functionalized gold surfaces do not differ significantly between isomers, which confirms the similar nature of the peptides i0, i1, and i2 but suggests that the macroscopic measurements are not able to distinguish specific sequences. The nanoprobe reveals a typical adhesion work value associated with the interaction of protofibrils with i0 and i2; this value is three times higher than that of i1. The difference is attributed to the hydrophobic nature of protofibrils, the predominant exposition of hydrophobic residues of the peptides i0 and i2, with respect to i1, and the degree of functionalization. i0 and i2 presented a slight adhesion with Aβ fibrils, which is associated with the exposed hydrophilic groups of these fibrils (onto HOPG) compared to the protofibrils. However, i1 showed interaction with both Aβ fibrils and protofibrils. For this, we propose an explanation based on the fact that the peptide i1 locates

  17. Sensitive imaging and effective capture of Cu(2+): Towards highly efficient theranostics of Alzheimer's disease.

    PubMed

    Cui, Zhaowen; Bu, Wenbo; Fan, Wenpei; Zhang, Jiawen; Ni, Dalong; Liu, Yanyan; Wang, Jing; Liu, Jianan; Yao, Zhenwei; Shi, Jianlin

    2016-10-01

    As a distinct feature of Alzheimer's disease (AD), the presence of excess metal ions in the brain is most probably one of the main causative factors for the aggregation of β-Amyloid (Aβ) proteins. The design of nanoprobes for detection and control of ion concentrations will be of great importance in predicting the progression of AD and simultaneously providing effective treatments. Herein, we report the design and synthesis of a novel yet smart nanoprobe that can sensitively detect the Cu(2+) concentration and concurrently capture Cu(2+) both in vitro and in vivo. The designed nanoprobe (UCHQ) combines two main components: upconversion nanoparticles (UCNPs) used for the detection and upconversion luminescence (UCL) imaging of Cu(2+) upon 980 nm exposure and the chelator 8-hydroxyquinoline-2-carboxylic acid (HQC) used for chelating Cu(2+) and AD therapy. The results show that the emission intensity of UCHQ is highly dependent on the Cu(2+) concentrations due to the luminescence resonance energy transfer (LRET) from UCNPs to HQC-bonded Cu(2+). Fascinatingly, the as-constructed UCHQs could be used for UCL imaging of Aβ both in cells and AD mice. Most importantly, UCHQs could not only inhibit the Aβ aggregation-induced apoptosis via capturing overmuch Cu(2+) but also accelerate the nontoxic structural transformation of Aβ. PMID:27454062

  18. In vitro and in vivo magnetic resonance imaging with chlorotoxin-conjugated superparamagnetic nanoprobes for targeting hepatocarcinoma.

    PubMed

    Chen, Zhu; Xiao, En-Hua; Kang, Zhen; Zeng, Wen-Bin; Tan, Hui-Long; Li, Hua-Bing; Bian, Du-Jun; Shang, Quan-Liang

    2016-05-01

    The present study aimed to assess the in vitro and in vivo magnetic resonance imaging (MRI) features of chlorotoxin (CTX)-conjugated superparamagnetic iron oxide (SPIO) nanoprobes. CTX-conjugated nanoprobes were composed of SPIO coated with polyethylene glycol (PEG) and conjugated with CTX. The nanoprobes were termed SPIO-PEG-CTX. MRI of the SPIO and SPIO-PEG-CTX solutions at a different concentration was performed with a 3.0-T MRI scanner (Philips Achieva 3.0T X Series; Phillips Healthcare, The Netherlands). Rabbit VX2 hepatocarcinoma was established by a traditional laparotomy method (injection of the tumor particles into the liver using a 15G syringe needle) following approval by the institutional animal care and use committee. Contrast-enhanced MRI of VX2 rabbits (n=8) was performed using the same MRI scanner with SPIO‑PEG-CTX solutions as the contrast agent. Data were analyzed with calibration curve and a paired t-test. The SPIO-PEG-CTX nanoparticles were successfully prepared. With increasing concentrations of the solutions, the MRI signal intensity was increased at T1WI, but decreased at T2WI, which were the same as that for SPIO. Rabbit VX2 carcinoma appeared as a low MRI signal at T1WI, and high at T2WI. After injection of the contrast agent, the MRI signal of carcinoma was decreased relative to that before injection at T2WI (1,161±331.5 vs. 1,346±300.5; P=0.004<0.05), while the signal of the adjacent normal hepatic tissues was unchanged (480.6±165.1 vs. 563.4±67.8; P=0.202>0.05). The SPIO-PEG-CTX nanoparticles showed MRI negative enhancement at T2WI and a targeting effect in liver cancer, which provides the theoretical basis for further study of the early diagnosis of hepatocellular carcinoma. PMID:26934940

  19. Commission 42: Close Binaries

    NASA Astrophysics Data System (ADS)

    Giménez, Alvaro; Rucinski, Slavek; Szkody, P.; Gies, D.; Kang, Y.-W.; Linsky, J.; Livio, M.; Morrell, N.; Hilditch, R.; Nordström, B.; Ribas, I.; Sion, E.; Vrielman, S.

    2007-03-01

    The triennial report from Commission 42 covers various topics like massive binaries, contact systems, cataclysmic variables and low-mass binary stars. We try in a number of sections to provide an update on the current status of the main research areas in the field of close binaries. It is not a formal review, even complete or comprehensive, but an attempt to bring the main topics on recent research to astronomers working in other fields. References are also not comprehensive and simply added to the text to help the reader looking for deeper information on the subject. For this reason, we have chosen to include references (sometimes incomplete for ongoing work) not in a list at the end but integrated with the main text body. Complete references and additional sources can be easily obtained through web access of ADS or SIMBAD. Furthermore, the summary of papers on close-binary research contained in the Bibliography of Close Binaries (BCB) can be accessed from the web site of Commission 42. I would like to express the gratitude of the commission for the careful work of Colin Scarfe as Editor-in-Chief of BCB and Andras Holl and Attila Sragli for maintaining the web pages of the Commission within the structure of Division V. Finally, K. Olah and J. Jurcsik are gratefully acknowledged for their continued support as editors of the Information Bulletin on Variable Stars (IBVS), also accessible through the commission web page.

  20. Virgin silver nanoparticles as colorimetric nanoprobe for simultaneous detection of iodide and bromide ion in aqueous medium

    NASA Astrophysics Data System (ADS)

    Bothra, Shilpa; Kumar, Rajender; Pati, Ranjan K.; Kuwar, Anil; Choi, Heung-Jin; Sahoo, Suban K.

    2015-10-01

    A simple colorimetric nanoprobe based on virgin silver nanoparticles (AgNPs) was developed for the selective detection of iodide and bromide ions via aggregation and anti-aggregation mechanism. With addition of I- ions, virgin AgNPs, in presence of Fe3+, showed perceptible color change from yellow to colorless along with disappearance of surface plasmon resonance (SPR) band of AgNPs at 400 nm. But in presence of Cr3+, AgNPs turned yellow upon addition of I-and Br- anions. The developed virgin AgNPs probe showed high specificity and selectivity with the detection limits down to 0.32 μM and 1.32 μM for I- ions via two different mechanistic routes. Also, the designed probe detects Br- with a detection limit down to 1.67 μM.

  1. X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens

    PubMed Central

    de Jonge, Martin D.; Ryan, Christopher G.; Jacobsen, Chris J.

    2014-01-01

    X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer. PMID:25177992

  2. Virgin silver nanoparticles as colorimetric nanoprobe for simultaneous detection of iodide and bromide ion in aqueous medium.

    PubMed

    Bothra, Shilpa; Kumar, Rajender; Pati, Ranjan K; Kuwar, Anil; Choi, Heung-Jin; Sahoo, Suban K

    2015-01-01

    A simple colorimetric nanoprobe based on virgin silver nanoparticles (AgNPs) was developed for the selective detection of iodide and bromide ions via aggregation and anti-aggregation mechanism. With addition of I(-) ions, virgin AgNPs, in presence of Fe(3+), showed perceptible color change from yellow to colorless along with disappearance of surface plasmon resonance (SPR) band of AgNPs at 400 nm. But in presence of Cr(3+), AgNPs turned yellow upon addition of I(-)and Br(-) anions. The developed virgin AgNPs probe showed high specificity and selectivity with the detection limits down to 0.32 μM and 1.32 μM for I(-) ions via two different mechanistic routes. Also, the designed probe detects Br(-) with a detection limit down to 1.67 μM. PMID:25950637

  3. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  4. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  5. Simulating Contact Binaries

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan; Clayton, Geoffrey C.; Frank, Juhan; Tohline, Joel E.; Staff, Jan E.; Motl, Patrick M.; Marcello, Dominic

    2014-06-01

    About one in every 150 stars is a contact binary system of WUMa type and it was thought for a long time that such a binary would naturally proceed towards merger, forming a single star. In September 2008 such a merger was observed in the eruption of a “red nova", V1309 Sco. We are developing a hydrodynamics simulation for contact binaries using Self Consistent Field (SCF) techniques, so that their formation, structural, and merger properties could be studied. This model can also be used to probe the stability criteria such as the large-scale equatorial circulations and the minimum mass ratio. We also plan to generate light curves from the simulation data in order to compare with the observed case of V1309 Sco. A comparison between observations and simulations will help us better understand the nova-like phenomena of stellar mergers.

  6. Gravity waves, chaos, and spinning compact binaries

    PubMed

    Levin

    2000-04-17

    Spinning compact binaries are shown to be chaotic in the post-Newtonian expansion of the two-body system. Chaos by definition is the extreme sensitivity to initial conditions and a consequent inability to predict the outcome of the evolution. As a result, the spinning pair will have unpredictable gravitational waveforms during coalescence. This poses a challenge to future gravity wave observatories which rely on a match between the data and a theoretical template. PMID:11019134

  7. Towards realistic simulations of non-vacuum compact binaries

    NASA Astrophysics Data System (ADS)

    Neilsen, David; Anderson, Matthew; Draper, Christian; Hirschmann, Eric; Lehner, Luis; Liebling, Steven; Miguel, Megevand; Motl, Patrick; Palenzuela, Carlos

    2011-04-01

    Binary mergers in non-vacuum spacetimes often display complex dynamics that are sensitive to the physical phenomena included in the model, and which may affect the gravitational wave signature from the system. For example, magnetic fields, cooling mechanisms, and equations of state influence the merger and post-merger evolution of compact binaries. Thus, these effects should be included in computational models that connect with astrophysical observations. In this talk we present results of neutron star evolutions with a finite-temperature equation of state in the context of binary mergers, and we also consider effects of other relevant physical phenomena.

  8. Identification list of binaries

    NASA Astrophysics Data System (ADS)

    Malkov,, O.; Karchevsky,, A.; Kaygorodov, P.; Kovaleva, D.

    The Identification List of Binaries (ILB) is a star catalogue constructed to facilitate cross-referencing between different catalogues of binary stars. As of 2015, it comprises designations for approximately 120,000 double/multiple systems. ILB contains star coordinates and cross-references to the Bayer/Flemsteed, DM (BD/CD/CPD), HD, HIP, ADS, WDS, CCDM, TDSC, GCVS, SBC9, IGR (and some other X-ray catalogues), PSR designations, as well as identifications in the recently developed BSDB system. ILB eventually became a part of the BDB stellar database.

  9. Binary coding for hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Chang, Chein-I.; Chang, Chein-Chi; Lin, Chinsu

    2004-10-01

    Binary coding is one of simplest ways to characterize spectral features. One commonly used method is a binary coding-based image software system, called Spectral Analysis Manager (SPAM) for remotely sensed imagery developed by Mazer et al. For a given spectral signature, the SPAM calculates its spectral mean and inter-band spectral difference and uses them as thresholds to generate a binary code word for this particular spectral signature. Such coding scheme is generally effective and also very simple to implement. This paper revisits the SPAM and further develops three new SPAM-based binary coding methods, called equal probability partition (EPP) binary coding, halfway partition (HP) binary coding and median partition (MP) binary coding. These three binary coding methods along with the SPAM well be evaluated for spectral discrimination and identification. In doing so, a new criterion, called a posteriori discrimination probability (APDP) is also introduced for performance measure.

  10. Self-Assembly of Electron Donor-Acceptor-Based Carbazole Derivatives: Novel Fluorescent Organic Nanoprobes for Both One- and Two-Photon Cellular Imaging.

    PubMed

    Zhang, Jinfeng; Chen, Wencheng; Kalytchuk, Sergii; Li, King Fai; Chen, Rui; Adachi, Chihaya; Chen, Zhan; Rogach, Andrey L; Zhu, Guangyu; Yu, Peter K N; Zhang, Wenjun; Cheah, Kok Wai; Zhang, Xiaohong; Lee, Chun-Sing

    2016-05-11

    In this study, we report fluorescent organic nanoprobes with intense blue, green, and orange-red emissions prepared by self-assembling three carbazole derivatives into nanorods/nanoparticles. The three compounds consist of two or four electron-donating carbazole groups linked to a central dicyanobenzene electron acceptor. Steric hindrance from the carbazole groups leads to noncoplanar 3D molecular structures favorable to fluorescence in the solid state, while the donor-acceptor structures endow the molecules with good two-photon excited emission properties. The fluorescent organic nanoprobes exhibit good water dispersibility, low cytotoxicity, superior resistance against photodegradation and photobleaching. Both one- and two-photon fluorescent imaging were shown in the A549 cell line. Two-photon fluorescence imaging with the fluorescent probes was demonstrated to be more effective in visualizing and distinguishing cellular details compared to conventional one-photon fluorescence imaging. PMID:27097920

  11. Dye-free near-infrared surface-enhanced Raman scattering nanoprobes for bioimaging and high-performance photothermal cancer therapy.

    PubMed

    Liu, Zhiming; Ye, Binggang; Jin, Mei; Chen, Haolin; Zhong, Huiqing; Wang, Xinpeng; Guo, Zhouyi

    2015-04-21

    Near-infrared surface-enhanced Raman scattering (NIR SERS) imaging is now a promising molecular imaging technology due to its narrow spectral bandwidth, low background interference and deep imaging depth. In this work, we report a novel strategy for fabrication of NIR SERS nanoprobes without using any expensive and highly toxic organic dyes. Multifunctional conducting polymer (CP) materials, serving as both biocompatible surface coatings and NIR-active reporters, are directly fabricated on the surface of gold nanorods (GNRs) via facile oxidative polymerization. The dye-free NIR SERS nanoprobes (GNR-CPs) exhibit good structural stability, good biocompatibility and intriguing NIR SERS activity. GNR-CPs also show an extraordinary NIR photothermal transduction efficiency, indicating the potential for cancer therapy. The applications of GNR-CPs as new types of theranostic agents for NIR SERS imaging and high-performance photothermal therapy are accomplished in vitro and in vivo. PMID:25804427

  12. Dye-free near-infrared surface-enhanced Raman scattering nanoprobes for bioimaging and high-performance photothermal cancer therapy

    NASA Astrophysics Data System (ADS)

    Liu, Zhiming; Ye, Binggang; Jin, Mei; Chen, Haolin; Zhong, Huiqing; Wang, Xinpeng; Guo, Zhouyi

    2015-04-01

    Near-infrared surface-enhanced Raman scattering (NIR SERS) imaging is now a promising molecular imaging technology due to its narrow spectral bandwidth, low background interference and deep imaging depth. In this work, we report a novel strategy for fabrication of NIR SERS nanoprobes without using any expensive and highly toxic organic dyes. Multifunctional conducting polymer (CP) materials, serving as both biocompatible surface coatings and NIR-active reporters, are directly fabricated on the surface of gold nanorods (GNRs) via facile oxidative polymerization. The dye-free NIR SERS nanoprobes (GNR-CPs) exhibit good structural stability, good biocompatibility and intriguing NIR SERS activity. GNR-CPs also show an extraordinary NIR photothermal transduction efficiency, indicating the potential for cancer therapy. The applications of GNR-CPs as new types of theranostic agents for NIR SERS imaging and high-performance photothermal therapy are accomplished in vitro and in vivo.Near-infrared surface-enhanced Raman scattering (NIR SERS) imaging is now a promising molecular imaging technology due to its narrow spectral bandwidth, low background interference and deep imaging depth. In this work, we report a novel strategy for fabrication of NIR SERS nanoprobes without using any expensive and highly toxic organic dyes. Multifunctional conducting polymer (CP) materials, serving as both biocompatible surface coatings and NIR-active reporters, are directly fabricated on the surface of gold nanorods (GNRs) via facile oxidative polymerization. The dye-free NIR SERS nanoprobes (GNR-CPs) exhibit good structural stability, good biocompatibility and intriguing NIR SERS activity. GNR-CPs also show an extraordinary NIR photothermal transduction efficiency, indicating the potential for cancer therapy. The applications of GNR-CPs as new types of theranostic agents for NIR SERS imaging and high-performance photothermal therapy are accomplished in vitro and in vivo. Electronic

  13. Folate Receptor-targeted Aggregation-enhanced Near-IR Emitting Silica Nanoprobe for One-photon in vivo and Two-photon ex vivo Fluorescence Bioimaging

    PubMed Central

    Wang, Xuhua; Morales, Alma R.; Urakami, Takeo; Zhang, Lifu; Bondar, Mykhailo V.; Komatsu, Masanobu; Belfield, Kevin D.

    2011-01-01

    A two-photon absorbing (2PA) and aggregation-enhanced near infrared (NIR) emitting pyran derivative, encapsulated in and stabilized by silica nanoparticles (SiNPs), is reported as a nanoprobe for two-photon fluorescence microscopy (2PFM) bioimaging that overcomes fluorescence quenching associated with high chromophore loading. The new SiNP probe exhibited aggregate-enhanced emission producing nearly twice as strong signal as the unaggregated dye, a three-fold increase in two-photon absorption relative to the DFP in solution, and approx. four-fold increase in photostability. The surface of the nanoparticles was functionalized with a folic acid (FA) derivative for folate-mediated delivery of the nanoprobe for 2PFM bioimaging. Surface modification of SiNPs with the FA derivative was supported by zeta potential variation and 1H NMR spectral characterization of the SiNPs as a function of surface modification. In vitro studies using HeLa cells expressing folate receptor (FR) indicated specific cellular uptake of the functionalized nanoparticles. The nanoprobe was demonstrated for FRtargeted one-photon in vivo imaging of HeLa tumor xenograft in mice upon intravenous injection of the probe. The FR-targeting nanoprobe not only exhibited highly selective tumor targeting but also readily extravasated from tumor vessels, penetrated into the tumor parenchyma, and was internalized by the tumor cells. Two-photon fluorescence microscopy bioimaging provided three-dimensional (3D) cellular-level resolution imaging up to 350 µm deep in the HeLa tumor. PMID:21688841

  14. Imaging mesenchymal stem cells containing single wall nanotube nanoprobes in a 3D scaffold using photo-thermal optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Connolly, Emma; Subhash, Hrebesh M.; Leahy, Martin; Rooney, Niall; Barry, Frank; Murphy, Mary; Barron, Valerie

    2014-02-01

    Despite the fact, that a range of clinically viable imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), photo emission tomography (PET), ultrasound and bioluminescence imaging are being optimised to track cells in vivo, many of these techniques are subject to limitations such as the levels of contrast agent required, toxic effects of radiotracers, photo attenuation of tissue and backscatter. With the advent of nanotechnology, nanoprobes are leading the charge to overcome these limitations. In particular, single wall nanotubes (SWNT) have been shown to be taken up by cells and as such are effective nanoprobes for cell imaging. Consequently, the main aim of this research is to employ mesenchymal stem cells (MSC) containing SWNT nanoprobes to image cell distribution in a 3D scaffold for cartilage repair. To this end, MSC were cultured in the presence of 32μg/ml SWNT in cell culture medium (αMEM, 10% FBS, 1% penicillin/streptomycin) for 24 hours. Upon confirmation of cell viability, the MSC containing SWNT were encapsulated in hyaluronic acid gels and loaded on polylactic acid polycaprolactone scaffolds. After 28 days in complete chondrogenic medium, with medium changes every 2 days, chondrogenesis was confirmed by the presence of glycosaminoglycan. Moreover, using photothermal optical coherence tomography (PT-OCT), the cells were seen to be distributed through the scaffold with high resolution. In summary, these data reveal that MSC containing SWNT nanoprobes in combination with PT-OCT offer an exciting opportunity for stem cell tracking in vitro for assessing seeding scaffolds and in vivo for determining biodistribution.

  15. Separation in Binary Alloys

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.

    1986-01-01

    Studies of monotectic alloys and alloy analogs reviewed. Report surveys research on liquid/liquid and solid/liquid separation in binary monotectic alloys. Emphasizes separation processes in low gravity, such as in outer space or in free fall in drop towers. Advances in methods of controlling separation in experiments highlighted.

  16. Binary concatenated coding system

    NASA Technical Reports Server (NTRS)

    Monford, L. G., Jr.

    1973-01-01

    Coding, using 3-bit binary words, is applicable to any measurement having integer scale up to 100. System using 6-bit data words can be expanded to read from 1 to 10,000, and 9-bit data words can increase range to 1,000,000. Code may be ''read'' directly by observation after memorizing simple listing of 9's and 10's.

  17. Binary primitive alternant codes

    NASA Technical Reports Server (NTRS)

    Helgert, H. J.

    1975-01-01

    In this note we investigate the properties of two classes of binary primitive alternant codes that are generalizations of the primitive BCH codes. For these codes we establish certain equivalence and invariance relations and obtain values of d and d*, the minimum distances of the prime and dual codes.

  18. Interacting binaries. Lecture notes 1992.

    NASA Astrophysics Data System (ADS)

    Nussbaumer, H.; Orr, A.

    These lecture notes represent a unique collection of information and references on current research on interacting binaries: S. N. Shore puts the emphasis on observations and their connection to relevant physics. He also discusses symbiotic stars. Cataclysmic variables are the subject of M. Livio's course, whereas E. P. J. van den Heuvel concentrates on more massive binaries and X-ray binaries.

  19. On the detectability of eccentric binary pulsars

    NASA Astrophysics Data System (ADS)

    Bagchi, Manjari; Lorimer, Duncan R.; Wolfe, Spencer

    2013-06-01

    By generalizing earlier work of Johnston and Kulkarni, we present a detailed description of the reduction in the signal-to-noise ratio for observations of binary pulsars. We present analytical expressions, and provide software, to calculate the sensitivity reduction for orbits of arbitrary eccentricity. We find that this reduction can be quite significant, especially in the case of a massive companion like another neutron star or a black hole. On the other hand, the reduction is less for highly eccentric orbits. We also demonstrate that this loss of sensitivity can be recovered by employing `acceleration search' or `acceleration-jerk search' algorithms.

  20. 808 nm-excited upconversion nanoprobes with low heating effect for targeted magnetic resonance imaging and high-efficacy photodynamic therapy in HER2-overexpressed breast cancer.

    PubMed

    Zeng, Leyong; Pan, Yuanwei; Zou, Ruifen; Zhang, Jinchao; Tian, Ying; Teng, Zhaogang; Wang, Shouju; Ren, Wenzhi; Xiao, Xueshan; Zhang, Jichao; Zhang, Lili; Li, Aiguo; Lu, Guangming; Wu, Aiguo

    2016-10-01

    To avoid the overheating effect of excitation light and improve the efficacy of photodynamic therapy (PDT) of upconversion nanoplatform, a novel nanoprobe based on 808 nm-excited upconversion nanocomposites (T-UCNPs@Ce6@mSiO2) with low heating effect and deep penetration has been successfully constructed for targeted upconversion luminescence, magnetic resonance imaging (MRI) and high-efficacy PDT in HER2-overexpressed breast cancer. In this nanocomposite, photosensitizers (Ce6) were covalently conjugated inside of mesoporous silica to enhance the PDT efficacy by shortening the distance of fluorescence resonance energy transfer and to decrease the cytotoxicity by preventing the undesired leakage of Ce6. Compared with UCNPs@mSiO2@Ce6, UCNPs@Ce6@mSiO2 greatly promoted the singlet oxygen generation and amplified the PDT efficacy under the excitation of 808 nm laser. Importantly, the designed nanoprobe can greatly improve the uptake of HER2-positive cells and tumors by modifying the site-specific peptide, and the in vivo experiments showed excellent MRI and PDT via intravenous injection by modeling MDA-MB-435 tumor-bearing nude mice. Our strategy may provide an effective solution for overcoming the heating effect and improving the PDT efficacy of upconversion nanoprobes, and has potential application in visualized theranostics of HER2-overexpressed breast cancer. PMID:27376560

  1. Binary Black Hole Mergers from Globular Clusters: Implications for Advanced LIGO.

    PubMed

    Rodriguez, Carl L; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Haster, Carl-Johan; Rasio, Frederic A

    2015-07-31

    The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. In this Letter, we study the formation of black hole binaries in an extensive collection of realistic globular cluster models. By comparing these models to observed Milky Way and extragalactic globular clusters, we find that the mergers of dynamically formed binaries could be detected at a rate of ∼100 per year, potentially dominating the binary black hole merger rate. We also find that a majority of cluster-formed binaries are more massive than their field-formed counterparts, suggesting that Advanced LIGO could identify certain binaries as originating from dense stellar environments. PMID:26274407

  2. Proposed search for the detection of gravitational waves from eccentric binary black holes

    NASA Astrophysics Data System (ADS)

    Tiwari, V.; Klimenko, S.; Christensen, N.; Huerta, E. A.; Mohapatra, S. R. P.; Gopakumar, A.; Haney, M.; Ajith, P.; McWilliams, S. T.; Vedovato, G.; Drago, M.; Salemi, F.; Prodi, G. A.; Lazzaro, C.; Tiwari, S.; Mitselmakher, G.; Da Silva, F.

    2016-02-01

    Most compact binary systems are expected to circularize before the frequency of emitted gravitational waves (GWs) enters the sensitivity band of the ground based interferometric detectors. However, several mechanisms have been proposed for the formation of binary systems, which retain eccentricity throughout their lifetimes. Since no matched-filtering algorithm has been developed to extract continuous GW signals from compact binaries on orbits with low to moderate values of eccentricity, and available algorithms to detect binaries on quasicircular orbits are suboptimal to recover these events, in this paper we propose a search method for detection of gravitational waves produced from the coalescences of eccentric binary black holes (eBBH). We study the search sensitivity and the false alarm rates on a segment of data from the second joint science run of LIGO and Virgo detectors, and discuss the implications of the eccentric binary search for the advanced GW detectors.

  3. Microfluidic binary phase flow

    NASA Astrophysics Data System (ADS)

    Angelescu, Dan; Menetrier, Laure; Wong, Joyce; Tabeling, Patrick; Salamitou, Philippe

    2004-03-01

    We present a novel binary phase flow regime where the two phases differ substantially in both their wetting and viscous properties. Optical tracking particles are used in order to investigate the details of such multiphase flow inside capillary channels. We also describe microfluidic filters we have developed, capable of separating the two phases based on capillary pressure. The performance of the filters in separating oil-water emulsions is discussed. Binary phase flow has been previously used in microchannels in applications such as emulsion generation, enhancement of mixing and assembly of custom colloidal paticles. Such microfluidic systems are increasingly used in a number of applications spanning a diverse range of industries, such as biotech, pharmaceuticals and more recently the oil industry.

  4. Binary Love relations

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Yunes, Nicolás

    2016-07-01

    When in a tight binary, the mutual tidal deformations of neutron stars get imprinted onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave (GW) observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the GW model. We here resolve this problem by discovering approximately equation-of-state (EoS)-insensitive relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the GW model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between EoS models, and improve tests of general relativity and cosmology.

  5. Contact binary stars

    NASA Astrophysics Data System (ADS)

    Mochnacki, S. W.

    1981-04-01

    Densities, corrected primary colors, minimum periods, inferred masses, luminosities, and specific angular momenta are computed from data on 37 W Ursae Majoris systems. A-type systems, having lower densities and angular momenta than the W-type systems, are shown to be evolved, and a new class of contact binary is identified, the OO Aquilae systems, whose members have evolved into contact. Evolutionary grids based on the contact condition agree with observation, except in that the evolved A-type systems have lost more angular momentum than predicted by gravitational radiation alone. This is accounted for by stellar wind magnetic braking, which is shown to be effective on a shorter time scale and to be important in other kinds of binaries containing a cool, tidally coupled component.

  6. Binary Optics Toolkit

    Energy Science and Technology Software Center (ESTSC)

    1996-04-02

    This software is a set of tools for the design and analysis of binary optics. It consists of a series of stand-alone programs written in C and some scripts written in an application-specific language interpreted by a CAD program called DW2000. This software can be used to optimize the design and placement of a complex lens array from input to output and produce contours, mask designs, and data exported for diffractive optic analysis.

  7. Parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.; Crockett, Thomas W.; Nicol, David M.

    1993-01-01

    Binary dissection is widely used to partition non-uniform domains over parallel computers. This algorithm does not consider the perimeter, surface area, or aspect ratio of the regions being generated and can yield decompositions that have poor communication to computation ratio. Parametric Binary Dissection (PBD) is a new algorithm in which each cut is chosen to minimize load + lambda x(shape). In a 2 (or 3) dimensional problem, load is the amount of computation to be performed in a subregion and shape could refer to the perimeter (respectively surface) of that subregion. Shape is a measure of communication overhead and the parameter permits us to trade off load imbalance against communication overhead. When A is zero, the algorithm reduces to plain binary dissection. This algorithm can be used to partition graphs embedded in 2 or 3-d. Load is the number of nodes in a subregion, shape the number of edges that leave that subregion, and lambda the ratio of time to communicate over an edge to the time to compute at a node. An algorithm is presented that finds the depth d parametric dissection of an embedded graph with n vertices and e edges in O(max(n log n, de)) time, which is an improvement over the O(dn log n) time of plain binary dissection. Parallel versions of this algorithm are also presented; the best of these requires O((n/p) log(sup 3)p) time on a p processor hypercube, assuming graphs of bounded degree. How PBD is applied to 3-d unstructured meshes and yields partitions that are better than those obtained by plain dissection is described. Its application to the color image quantization problem is also discussed, in which samples in a high-resolution color space are mapped onto a lower resolution space in a way that minimizes the color error.

  8. Evolutionary models of binaries

    NASA Astrophysics Data System (ADS)

    van Rensbergen, Walter; Mennekens, Nicki; de Greve, Jean-Pierre; Jansen, Kim; de Loore, Bert

    2011-07-01

    We have put on CDS a catalog containing 561 evolutionary models of binaries: J/A+A/487/1129 (Van Rensbergen+, 2008). The catalog covers a grid of binaries with a B-type primary at birth, different values for the initial mass ratio and a wide range of initial orbital periods. The evolution was calculated with the Brussels code in which we introduced the spinning up and the creation of a hot spot on the gainer or its accretion disk, caused by impacting mass coming from the donor. When the kinetic energy of fast rotation added to the radiative energy of the hot spot exceeds the binding energy, a fraction of the transferred matter leaves the system: the evolution is liberal during a short lasting era of rapid mass transfer. The spin-up of the gainer was modulated using both strong and weak tides. The catalog shows the results for both types. For comparison, we included the evolutionary tracks calculated with the conservative assumption. Binaries with an initial primary below 6 Msolar show hardly any mass loss from the system and thus evolve conservatively. Above this limit differences between liberal and conservative evolution grow with increasing initial mass of the primary star.

  9. Searching for gravitational waves from binary coalescence

    NASA Astrophysics Data System (ADS)

    Babak, S.; Biswas, R.; Brady, P. R.; Brown, D. A.; Cannon, K.; Capano, C. D.; Clayton, J. H.; Cokelaer, T.; Creighton, J. D. E.; Dent, T.; Dietz, A.; Fairhurst, S.; Fotopoulos, N.; González, G.; Hanna, C.; Harry, I. W.; Jones, G.; Keppel, D.; McKechan, D. J. A.; Pekowsky, L.; Privitera, S.; Robinson, C.; Rodriguez, A. C.; Sathyaprakash, B. S.; Sengupta, A. S.; Vallisneri, M.; Vaulin, R.; Weinstein, A. J.

    2013-01-01

    We describe the implementation of a search for gravitational waves from compact binary coalescences in LIGO and Virgo data. This all-sky, all-time, multidetector search for binary coalescence has been used to search data taken in recent LIGO and Virgo runs. The search is built around a matched filter analysis of the data, augmented by numerous signal consistency tests designed to distinguish artifacts of non-Gaussian detector noise from potential detections. We demonstrate the search performance using Gaussian noise and data from the fifth LIGO science run and demonstrate that the signal consistency tests are capable of mitigating the effect of non-Gaussian noise and providing a sensitivity comparable to that achieved in Gaussian noise.

  10. An individually coated near-infrared fluorescent protein as a safe and robust nanoprobe for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Yang, Yu; Xiang, Kun; Yang, Yi-Xin; Wang, Yan-Wen; Zhang, Xin; Cui, Yangdong; Wang, Haifang; Zhu, Qing-Qing; Fan, Liqiang; Liu, Yuanfang; Cao, Aoneng

    2013-10-01

    A prerequisite for in vivo fluorescence imaging is the safety of fluorescent probes. Among all fluorescent probes, fluorescent proteins (FPs) might be the safest ones, which have been widely used in biological sciences at the gene level. But FPs have not been used in vivo in the purified form yet due to the instability of proteins. Here, we individually coat near-infrared (NIR) FPs (NIRFPs) with a silica nanoshell, resulting in NIRFP@silica, one of the safest and brightest NIR fluorescent nanoprobes with a quantum yield of 0.33 for in vivo imaging. The silica shell not only protects NIRFPs from denaturation and metabolic digestion, but also enhances the quantum yield and photostability of the coated NIRFPs. When injected via the tail vein, NIRFP@silica NPs can distribute all over the mouse body, and then can be efficiently eliminated through urine in 24 h, demonstrating its potential applications as a safe and robust NIR fluorescence probe for whole body imaging.A prerequisite for in vivo fluorescence imaging is the safety of fluorescent probes. Among all fluorescent probes, fluorescent proteins (FPs) might be the safest ones, which have been widely used in biological sciences at the gene level. But FPs have not been used in vivo in the purified form yet due to the instability of proteins. Here, we individually coat near-infrared (NIR) FPs (NIRFPs) with a silica nanoshell, resulting in NIRFP@silica, one of the safest and brightest NIR fluorescent nanoprobes with a quantum yield of 0.33 for in vivo imaging. The silica shell not only protects NIRFPs from denaturation and metabolic digestion, but also enhances the quantum yield and photostability of the coated NIRFPs. When injected via the tail vein, NIRFP@silica NPs can distribute all over the mouse body, and then can be efficiently eliminated through urine in 24 h, demonstrating its potential applications as a safe and robust NIR fluorescence probe for whole body imaging. Electronic supplementary information (ESI

  11. Fe XXV line profiles in colliding wind binaries

    NASA Astrophysics Data System (ADS)

    Rauw, Gregor; Mossoux, Enmanuelle; Nazé, Yaël

    2016-02-01

    Strong wind-wind collisions in massive binaries generate a very hot plasma that frequently produces a moderately strong iron line. The morphology of this line depends upon the properties of the wind interaction zone and its orientation with respect to the line of sight. As the binary components revolve around their common centre of mass, the line profiles are thus expected to vary. With the advent of the next generation of X-ray observatories (Astro-H, Athena) that will offer high-resolution spectroscopy above 6 keV, it will become possible to exploit these changes as the most sensitive probe of the inner parts of the colliding wind interaction. Using a simple prescription of the wind-wind interaction in an early-type binary, we have generated synthetic line profiles for a number of configurations and orbital phases. These profiles can help constrain the properties of the stellar winds in such binary systems.

  12. Binary-Signal Recovery

    NASA Technical Reports Server (NTRS)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  13. Binary optics: Trends and limitations

    NASA Technical Reports Server (NTRS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-01-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  14. The Search for Trojan Binaries

    NASA Astrophysics Data System (ADS)

    Merline, William J.; Tamblyn, P. M.; Dumas, C.; Close, L. M.; Chapman, C. R.; Durda, D. D.; Levison, H. F.; Hamilton, D. P.; Nesvorny, D.; Storrs, A.; Enke, B.; Menard, F.

    2007-10-01

    We report on observations of Jupiter Trojan asteroids in search of binaries. We made observations using HST/ACS of 35 small (V = 17.5-19.5) objects in Cycle 14, without detecting any binaires. We have also observed a few dozen Trojans in our ground-based study of larger Trojans, discovering only one binary. The result is that the frequency of moderately-separated binaries among the Trojans seem rather low, likely less than 5%. Although we have only statistics of small numbers, it appears that the binary frequencies are more akin to the larger Main-Belt asteroids, than to the frequency in the TNO region, which probably exceeds 10%. The low frequency is inconsistent with the projections based on Trojan contact binaries by Mann et al. (2006, BAAS 38, 6509), although our work cannot detect very close or contact binaries. We discovered and characterized the orbit and density of the first Trojan binary, (617) Patroclus using the Gemini AO system (Merline et al. 2001 IAUC 7741). A second binary, (624) Hecktor, has now been reported by Marchis et al. (2006, IAUC 8732). In a broad survey of Main Belt asteroids, we found that, among the larger objects, the binary fraction is about 2%, while we are finding that the fraction is significantly higher among smaller asteroids (and this is even more apparent from lightcurve discoveries). Further, characteristics of these smaller systems indicate a distinctly different formation mechanism the the larger MB binaries. Because the Trojans have compositions that are more like the KBOs, while they live in a collisional environment much more like the Main Belt than the KBOs, these objects should hold vital clues to binary formation mechanics. And because there seems to be a distinct difference in larger and smaller main-belt binaries, we sought to detect such differences among the Trojans as well.

  15. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  16. A Microliter-Scale High-throughput Screening System with Quantum-Dot Nanoprobes for Amyloid-β Aggregation Inhibitors

    PubMed Central

    Ishigaki, Yukako; Tanaka, Hiroyuki; Akama, Hiroaki; Ogara, Toshiki; Uwai, Koji; Tokuraku, Kiyotaka

    2013-01-01

    The aggregation of amyloid β protein (Aβ) is a key step in the pathogenesis of Alzheimer’s disease (AD), and therefore inhibitory substances for Aβ aggregation may have preventive and/or therapeutic potential for AD. Here we report a novel microliter-scale high-throughput screening system for Aβ aggregation inhibitors based on fluorescence microscopy-imaging technology with quantum-dot Nanoprobes. This screening system could be analyzed with a 5-µl sample volume when a 1536-well plate was used, and the inhibitory activity could be estimated as half-maximal effective concentrations (EC50). We attempted to comprehensively screen Aβ aggregation inhibitors from 52 spices using this system to assess whether this novel screening system is actually useful for screening inhibitors. Screening results indicate that approximately 90% of the ethanolic extracts from the spices showed inhibitory activity for Aβ aggregation. Interestingly, spices belonging to the Lamiaceae, the mint family, showed significantly higher activity than the average of tested spices. Furthermore, we tried to isolate the main inhibitory compound from Saturejahortensis, summer savory, a member of the Lamiaceae, using this system, and revealed that the main active compound was rosmarinic acid. These results demonstrate that this novel microliter-scale high-throughput screening system could be applied to the actual screening of Aβ aggregation inhibitors. Since this system can analyze at a microscopic scale, it is likely that further minimization of the system would easily be possible such as protein microarray technology. PMID:23991168

  17. Peptide-functionalized ZCIS QDs as fluorescent nanoprobe for targeted HER2-positive breast cancer cells imaging.

    PubMed

    Michalska, Martyna; Florczak, Anna; Dams-Kozlowska, Hanna; Gapinski, Jacek; Jurga, Stefan; Schneider, Raphaël

    2016-04-15

    In this paper, the synthesis of alloyed CuInZnxS2+x quantum dots (ZCIS QDs), their transfer into aqueous solution via a polymer coating technique, and the use of these nanocrystals to selectively target HER2-positive cells, are reported. By optimizing first the ZnS shell deposition process onto the CuInS2 core, and next the encapsulation of the dots with the amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) polymer, water-dispersible ZCIS QDs were successfully prepared. The nanocrystals with a photoluminescence quantum yield of 35% were purified via centrifugation and ultracentrifugation and high quality nanoparticles with narrow size distributions and surface charges were obtained. After verifying the biocompatibility of PMO-coated ZCIS QDs, we coupled these nanocrystals with the LTVSPWY peptide and demonstrated via MTT assay that both bare and the peptide-linked QDs exhibit low cytotoxicity. The HER2-mediated delivery of the peptide-linked QDs was confirmed by confocal microscopy. This study indicates that as engineered QDs can efficiently be used as fluorescent nanoprobes for selective labelling of HER2-positive SKBR3 cancer cells. PMID:26850146

  18. White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

    SciTech Connect

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  19. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    SciTech Connect

    Benson, C.; Jaski, Y.; Powers, T.; Schmidt, O.; Rossi, E.; Maser, J.

    2007-01-19

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  20. Application of micro- and nanoprobes to the analysis of small-sized 3D materials, nanosystems, and nanoobjects

    NASA Astrophysics Data System (ADS)

    Pogrebnjak, A. D.; Ponomarev, A. G.; Shpak, Anatolii P.; Kunitskii, Yu A.

    2012-03-01

    The basic physics behind the interaction of ions with solid-state matter is discussed, with an emphasis on the formation of interaction products between the ions and target atoms. Processes covering modification of high-resistance materials for use in small-sized 3D structure technology are described. Current trends in and problems facing the development of the scanning nuclear microprobe (SNMP) are reviewed. The application of slow positrons to diagnosing materials is examined and the techniques of positron microscopy and microprobing are presented. The potential of near-field microwave microscopy for diagnosing superconducting ceramics and of microwave microscopy for nanotechnology applications are assessed. The examples given include the use of micro- and nanoprobes to analyze nanoobjects (such as green algae cells with 3D-distributed microelements, etc.), to develop the topological aspects of integrated microcircuits in nanoelectronics, and some other applications. The role of iron in pathogenesis of Parkinson's disease is highlighted, the latter being the subject of research in neurochemistry.

  1. Cell nucleus targeting for living cell extraction of nucleic acid associated proteins with intracellular nanoprobes of magnetic carbon nanotubes.

    PubMed

    Zhang, Yi; Hu, Zhengyan; Qin, Hongqiang; Liu, Fangjie; Cheng, Kai; Wu, Ren'an; Zou, Hanfa

    2013-08-01

    Since nanoparticles could be ingested by cells naturally and target at a specific cellular location as designed, the extraction of intracellular proteins from living cells for large-scale analysis by nanoprobes seems to be ideally possible. Nucleic acid associated proteins (NAaP) take the crucial position during biological processes in maintaining and regulating gene structure and gene related behaviors, yet there are still challenges during the global investigation of intracellular NAaP, especially from living cells. In this work, a strategy to extract intracellular proteins from living cells with the magnetic carbon nanotube (oMWCNT@Fe3O4) as an intracellular probe is developed, to achieve the high throughput analysis of NAaP from living human hepatoma BEL-7402 cells with a mass spectrometry-based proteomic approach. Due to the specific intracellular localization of the magnetic carbon nanotubes around nuclei and its strong interaction with nucleic acids, the highly efficient extraction was realized for cellular NAaP from living cells, with the capability of identifying 2383 intracellular NAaP from only ca. 10,000 living cells. This method exhibited potential applications in dynamic and in situ analysis of intracellular proteins. PMID:23815738

  2. Multimodal hard x-ray nanoprobe facility by nested Montel mirrors aimed for 40nm resolution at Taiwan Photon Source

    NASA Astrophysics Data System (ADS)

    Yin, Gung-Chian; Chang, Shi-Hung; Chen, Bo-Yi; Chen, Huang-Yeh; Lin, Bi-Hsuan; Tseng, Shao-Chin; Lee, Chian-Yao; Wu, Shao-Yun; Tang, Mau-Tsu

    2016-01-01

    The hard X-ray nanoprobe facility at Taiwan Photon Source (TPS) provides multimodal X-ray detections, including XRF, XAS, XEOL, projection microscope, CDI, etc. Resulting from the large numerical aperture obtained by utilizing nested Montel mirrors, the beamline with a moderate length 75 meters can conduct similar performance with those beamlines longer than 100 meters. The mirrors are symmetrically placed with a 45 degrees cut. The beamline optics is thus designed to take the advantage of the symmetry of mirrors such that a round focal spot is accomplished. The size and the divergence of the focus spot are simulated around 40 nm and 6.29 mrad, respectively. The whole facility including the beamline and the stations will be operated under vacuum to preserve the photon coherence as well as to prevent the system from unnecessary environmental interference. A SEM in close cooperation with laser interferometers is equipped to precisely locate the position of the sample. This endstation is scheduled to be commissioned in the fall of 2016.

  3. The properties of Gd2O3-assembled silica nanocomposite targeted nanoprobes and their application in MRI.

    PubMed

    Shao, Yuanzhi; Tian, Xiumei; Hu, Wenyong; Zhang, Yongyu; Liu, Huan; He, Haoqiang; Shen, Yingying; Xie, Fukang; Li, Li

    2012-09-01

    The feasibility of the gadolinium-doped mesoporous silica nanocomposite Gd(2)O(3)@MCM-41 as a safe, effective MRI nanoprobe has been validated in the current investigation systematically from atomistic and molecular modeling to its synthesis and characterization on in vivo MR imaging and biocompatibility. The first-principles calculation indicates that it is nearly impossible for toxic Gd ions to dissociate freely from silica. The biocompatibility studies confirm that the nanocomposite is lack of any potential toxicity; the biodistribution studies reveal a greater accumulation of the nanocomposite in liver, spleen, lung and tumor than in kidney, heart and brain; the excretion studies show that the nanocomposite can be cleared nearly 50% via the hepatobiliary transport mechanism after 1.5 months of injection. A larger water proton relaxivity r(1) and a better T(1)-weighted phantom MR imaging capability were detected in the nanocomposite than in the commercially available gadolinium diethylenetriaminepentaacetate. The results demonstrate that the nanocomposite is superior to the commercial counterpart in terms of contrast enhancement with a satisfactory biocompatibility, and it has a high potential to be developed into a safe and effective targeted probe for in vivo molecular imaging of cancer. PMID:22704842

  4. SEARCH FOR SUPERMASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

    SciTech Connect

    Ju, Wenhua; Greene, Jenny E.; Rafikov, Roman R.; Bickerton, Steven J.; Badenes, Carles

    2013-11-01

    Supermassive black hole (SMBH) binaries are expected in a ΛCDM cosmology given that most (if not all) massive galaxies contain a massive black hole (BH) at their center. So far, however, direct evidence for such binaries has been elusive. We use cross-correlation to search for temporal velocity shifts in the Mg II broad emission lines of 0.36 < z < 2 quasars with multiple observations in the Sloan Digital Sky Survey. For ∼10{sup 9} M{sub ☉} BHs in SMBH binaries, we are sensitive to velocity drifts for binary separations of ∼0.1 pc with orbital periods of ∼100 yr. We find seven candidate sub-parsec-scale binaries with velocity shifts >3.4σ ∼ 280 km s{sup –1}, where σ is our systematic error. Comparing the detectability of SMBH binaries with the number of candidates (N ≤ 7), we can rule out that most 10{sup 9} M{sub ☉} BHs exist in ∼0.03-0.2 pc scale binaries, in a scenario where binaries stall at sub-parsec scales for a Hubble time. We further constrain that ≤16% (one-third) of quasars host SMBH binaries after considering gas-assisted sub-parsec evolution of SMBH binaries, although this result is very sensitive to the assumed size of the broad line region. We estimate the detectability of SMBH binaries with ongoing or next-generation surveys (e.g., Baryon Oscillation Spectroscopic Survey, Subaru Prime Focus Spectrograph), taking into account the evolution of the sub-parsec binary in circumbinary gas disks. These future observations will provide longer time baselines for searches similar to ours and may in turn constrain the evolutionary scenarios of SMBH binaries.

  5. Evolution of Close Binary Systems

    SciTech Connect

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  6. Low autocorrelation binary sequences

    NASA Astrophysics Data System (ADS)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  7. BINARY STORAGE ELEMENT

    DOEpatents

    Chu, J.C.

    1958-06-10

    A binary storage device is described comprising a toggle provided with associsted improved driver circuits adapted to produce reliable action of the toggle during clearing of the toggle to one of its two states. or transferring information into and out of the toggle. The invention resides in the development of a self-regulating driver circuit to minimize the fluctuation of the driving voltages for the toggle. The disclosed driver circuit produces two pulses in response to an input pulse: a first or ''clear'' pulse beginning nt substantially the same time but endlrg slightly sooner than the second or ''transfer'' output pulse.

  8. The ζ Aurigae Binaries

    NASA Astrophysics Data System (ADS)

    Griffin, R. Elizabeth; Ake, Thomas B.

    This opening chapter provides a brief historical overview of the ζ Aur stars, with a focus on what K.O. Wright, his predecessors and colleagues at the Dominion Astrophysical Observatory, and his contemporaries further afield, achieved during the era of pre-electronic data. It places the topic within the framework of modern observing, data management and computing, outlines the principal features of the chromospheric-eclipse phenomena which single out the ζ Aur binaries for special study, and describes the considerable potential which this remarkable yet very select group of stars offers for increasing our understanding of stellar physics.

  9. Koronis binaries and the role of families in binary frequency

    NASA Astrophysics Data System (ADS)

    Merline, W. J.; Tamblyn, P. M.; Nesvorny, D.; Durda, D. D.; Chapman, C. R.; Dumas, C.; Owen, W. M.; Storrs, A. D.; Close, L. M.; Menard, F.

    2005-08-01

    Our ground-based adaptive optics observations of many larger Koronis members show no binaries, while our HST survey of smaller Koronis members (say smaller than 10 km) shows a surprising 20% binary fraction. Admittedly, this is from small-number statistics, but we nonetheless calculate a 99% confidence that the binary fraction is different from the 2% we observe among the larger (over 20km) main belt asteroids as a whole. In addition, we estimate that among the two young families (Karin and Veritas) that we surveyed for binaries in our HST Cy 13 program, the binary fraction appears to be less than 5%. These young families both have significantly smaller progenitors than the Koronis family. We have speculated that progenitor size may be a more important factor than age in determination of binary frequency. But here we suggest an alternative idea, that the binary fraction may be more related to what part of the family's size distribution is sampled. Our HST program targeted objects of the same physical sizes, but was clearly sampling further down the size distribution (to smaller sizes, relative to the largest remnant) in the Koronis sample than was the case for Karin and Veritas, which we sampled mostly at the larger sizes, relatively. Our SPH collision models are estimating the typical size-frequency distributions to be expected from catastrophic and non-catastrophic impact events. But they are also appear to be showing that the largest fragments from a collision are less likely to form binaries (as co-orbiting ejecta pairs) than are the smaller fragments. Thus, it might be expected that we would have found fewer binaries among Karin and Veritas than among the Koronis sample. In fact, models of the Karin breakup show binary formation to be unlikely in the size range measured. It some might be tempted to tie the small end of the main-belt binary population to the binaries seen among the NEAs (also small and also showing about 20% fraction), given the 20% fraction

  10. Modeling Binary Neutron Stars

    NASA Astrophysics Data System (ADS)

    Park, Conner; Read, Jocelyn; Flynn, Eric; Lockett-Ruiz, Veronica

    2016-03-01

    Gravitational waves, predicted by Einstein's Theory of Relativity, are a new frontier in astronomical observation we can use to observe phenomena in the universe. Laser Interferometer Gravitational wave Observatory (LIGO) is currently searching for gravitational wave signals, and requires accurate predictions in order to best extract astronomical signals from all other sources of fluctuations. The focus of my research is in increasing the accuracy of Post-Newtonian models of binary neutron star coalescence to match the computationally expensive Numerical models. Numerical simulations can take months to compute a couple of milliseconds of signal whereas the Post-Newtonian can generate similar signals in seconds. However the Post-Newtonian model is an approximation, e.g. the Taylor T4 Post-Newtonian model assumes that the two bodies in the binary neutron star system are point charges. To increase the effectiveness of the approximation, I added in tidal effects, resonance frequencies, and a windowing function. Using these observed effects from simulations significantly increases the Post-Newtonian model's similarity to the Numerical signal.

  11. Expected Bounds on Compact Binary Coalescence Rates from LIGO Observations

    NASA Astrophysics Data System (ADS)

    Sampson, Laura; LIGO Scientific Collaboration Collaboration

    2016-03-01

    The Advanced LIGO detectors have recently completed their first observing run, with a sensitive spacetime volume over 27 times larger than the initial LIGO configuration. In this talk we will examine the expected bounds on compact binary coalescence rates from O1 observations, and discuss the corresponding impact on astrophysical models.

  12. The LIGO Scientific Collaboration search for inspiralling binary neutron stars

    NASA Astrophysics Data System (ADS)

    Brown, Duncan

    2006-04-01

    The three LIGO interferometers and the GEO600 interferometer operate as a network of detectors under the LIGO Scientific Collaboration (LSC). This network has now reached unprecedented levels of sensitivity. In this talk we will present the status and current results from the binary neutron star search in LIGO/GEO data.

  13. THE CLOSE BINARY FRACTION OF DWARF M STARS

    SciTech Connect

    Clark, Benjamin M.; Blake, Cullen H.; Knapp, Gillian R.

    2012-01-10

    We describe a search for close spectroscopic dwarf M star binaries using data from the Sloan Digital Sky Survey to address the question of the rate of occurrence of multiplicity in M dwarfs. We use a template-fitting technique to measure radial velocities from 145,888 individual spectra obtained for a magnitude-limited sample of 39,543 M dwarfs. Typically, the three or four spectra observed for each star are separated in time by less than four hours, but for {approx}17% of the stars, the individual observations span more than two days. In these cases we are sensitive to large-amplitude radial velocity variations on timescales comparable to the separation between the observations. We use a control sample of objects having observations taken within a four-hour period to make an empirical estimate of the underlying radial velocity error distribution and simulate our detection efficiency for a wide range of binary star systems. We find the frequency of binaries among the dwarf M stars with a < 0.4 AU to be 3%-4%. Comparison with other samples of binary stars demonstrates that the close binary fraction, like the total binary fraction, is an increasing function of primary mass.

  14. Misaligned protoplanetary disks in a young binary star system.

    PubMed

    Jensen, Eric L N; Akeson, Rachel

    2014-07-31

    Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star's equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet's orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in a few young binaries are misaligned, but often the measurements of these misalignments are sensitive only to a small portion of the inner disk, and the three-dimensional misalignment of the bulk of the planet-forming disk mass has hitherto not been determined. Here we report that the protoplanetary disks in the young binary system HK Tauri are misaligned by 60 to 68 degrees, such that one or both of the disks are significantly inclined to the binary orbital plane. Our results demonstrate that the necessary conditions exist for misalignment-driven mechanisms to modify planetary orbits, and that these conditions are present at the time of planet formation, apparently because of the binary formation process. PMID:25079553

  15. Multilevel Models for Binary Data

    ERIC Educational Resources Information Center

    Powers, Daniel A.

    2012-01-01

    The methods and models for categorical data analysis cover considerable ground, ranging from regression-type models for binary and binomial data, count data, to ordered and unordered polytomous variables, as well as regression models that mix qualitative and continuous data. This article focuses on methods for binary or binomial data, which are…

  16. THIRTY NEW LOW-MASS SPECTROSCOPIC BINARIES

    SciTech Connect

    Shkolnik, Evgenya L.; Hebb, Leslie; Cameron, Andrew C.; Liu, Michael C.; Neill Reid, I. E-mail: Andrew.Cameron@st-and.ac.u E-mail: mliu@ifa.hawaii.ed

    2010-06-20

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P{sub rot} to determine the true orbital parameters. For those with no P{sub rot}, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems.

  17. Far-Red and Near-IR AIE-Active Fluorescent Organic Nanoprobes with Enhanced Tumor-Targeting Efficacy: Shape-Specific Effects.

    PubMed

    Shao, Andong; Xie, Yongshu; Zhu, Shaojia; Guo, Zhiqian; Zhu, Shiqin; Guo, Jin; Shi, Ping; James, Tony D; Tian, He; Zhu, Wei-Hong

    2015-06-15

    The rational design of high-performance fluorescent materials for cancer targeting in vivo is still challenging. A unique molecular design strategy is presented that involves tailoring aggregation-induced emission (AIE)-active organic molecules to realize preferable far-red and NIR fluorescence, well-controlled morphology (from rod-like to spherical), and also tumor-targeted bioimaging. The shape-tailored organic quinoline-malononitrile (QM) nanoprobes are biocompatible and highly desirable for cell-tracking applications. Impressively, the spherical shape of QM-5 nanoaggregates exhibits excellent tumor-targeted bioimaging performance after intravenously injection into mice, but not the rod-like aggregates of QM-2. PMID:25950152

  18. Searching for gravitational waves from compact binaries with precessing spins

    NASA Astrophysics Data System (ADS)

    Harry, Ian; Privitera, Stephen; Bohé, Alejandro; Buonanno, Alessandra

    2016-07-01

    Current searches for gravitational waves from compact-object binaries with the LIGO and Virgo observatories employ waveform models with spins aligned (or antialigned) with the orbital angular momentum. Here, we derive a new statistic to search for compact objects carrying generic (precessing) spins. Applying this statistic, we construct banks of both aligned- and generic-spin templates for binary black holes and neutron star-black hole binaries, and compare the effectualness of these banks towards simulated populations of generic-spin systems. We then use these banks in a pipeline analysis of Gaussian noise to measure the increase in background incurred by using generic- instead of aligned-spin banks. Although the generic-spin banks have roughly a factor of ten more templates than the aligned-spin banks, we find an overall improvement in signal recovery at a fixed false-alarm rate for systems with high-mass ratio and highly precessing spins. This gain in sensitivity comes at a small loss of sensitivity (≲4 %) for systems that are already well covered by aligned-spin templates. Since the observation of even a single binary merger with misaligned spins could provide unique astrophysical insights into the formation of these sources, we recommend that the method described here be developed further to mount a viable search for generic-spin binary mergers in LIGO/Virgo data.

  19. PROSPECTS FOR DETECTING ASTEROSEISMIC BINARIES IN KEPLER DATA

    SciTech Connect

    Miglio, A.; Chaplin, W. J.; Elsworth, Y.; Handberg, R.; Farmer, R.; Kolb, U.; Girardi, L.; Appourchaux, T.

    2014-03-20

    Asteroseismology may in principle be used to detect unresolved stellar binary systems comprised of solar-type stars and/or red giants. This novel method relies on the detection of the presence of two solar-like oscillation spectra in the frequency spectrum of a single light curve. Here, we make predictions of the numbers of systems that may be detectable in data already collected by the NASA Kepler Mission. Our predictions, which are based upon TRILEGAL and BiSEPS simulations of the Kepler field of view, indicate that as many as 200 or more ''asteroseismic binaries'' may be detectable in this manner. Most of these binaries should be comprised of two He-core-burning red giants. Owing largely to the limited numbers of targets with the requisite short-cadence Kepler data, we expect only a small number of detected binaries containing solar-type stars. The predicted yield of detections is sensitive to the assumed initial mass ratio distribution (IMRD) of the binary components and therefore represents a sensitive calibration of the much debated IMRD near mass ratio unity.

  20. Secure and robust steganographic algorithm for binary images

    NASA Astrophysics Data System (ADS)

    Agaian, Sos S.; Cherukuri, Ravindranath

    2006-05-01

    In recent years, active research has mainly concentrated on authenticating a signature; tracking a document in a digital library, and tamper detection of a scanned document or secured communication using binary images. Binary image steganographical systems provide a solution for the above discussed issues. The two color constraint of the image limits the extension of various LSB embedding techniques to the binary case. In this paper, we present a new data hiding system for binary images and scanned documents. The system initially identifies embeddable blocks and enforces specific block statistics to hide sensitive information. The distribution of the flippable pixels in these blocks is highly uneven over the image. A variable block embedding threshold is employed for capitalizing on this uneven distribution of pixels. In addition, we also present a measure to find the best the cover given a specific file of sensitive information. The simulation was performed over 50 various binary images such the scanned documents, cartoons, threshold color images. Simulation results shows that 1) The amount of data embedded is comparatively higher than the existing algorithms (such as K.H. Hwang et.al [5], J. Chen et.al [10], M.Y.Wu et.al [9]). 2) The visual distortion in cover image is minimal when compared with the existing algorithms (such as J. Chen[10], M.Y.Wu et.al [9]) will be presented.

  1. Signature Visualization of Software Binaries

    SciTech Connect

    Panas, T

    2008-07-01

    In this paper we present work on the visualization of software binaries. In particular, we utilize ROSE, an open source compiler infrastructure, to pre-process software binaries, and we apply a landscape metaphor to visualize the signature of each binary (malware). We define the signature of a binary as a metric-based layout of the functions contained in the binary. In our initial experiment, we visualize the signatures of a series of computer worms that all originate from the same line. These visualizations are useful for a number of reasons. First, the images reveal how the archetype has evolved over a series of versions of one worm. Second, one can see the distinct changes between version. This allows the viewer to form conclusions about the development cycle of a particular worm.

  2. Contact Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Rieger, Samantha

    2015-05-01

    Recent observations have found that some contact binaries are oriented such that the secondary impacts with the primary at a high inclination. This research investigates the evolution of how such contact binaries came to exist. This process begins with an asteroid pair, where the secondary lies on the Laplace plane. The Laplace plane is a plane normal to the axis about which the pole of a satellites orbit precesses, causing a near constant inclination for such an orbit. For the study of the classical Laplace plane, the secondary asteroid is in circular orbit around an oblate primary with axial tilt. This system is also orbiting the Sun. Thus, there are two perturbations on the secondarys orbit: J2 and third body Sun perturbations. The Laplace surface is defined as the group of orbits that lie on the Laplace plane at varying distances from the primary. If the secondary is very close to the primary, the inclination of the Laplace plane will be near the equator of the asteroid, while further from the primary the inclination will be similar to the asteroid-Sun plane. The secondary will lie on the Laplace plane because near the asteroid the Laplace plane is stable to large deviations in motion, causing the asteroid to come to rest in this orbit. Assuming the secondary is asymmetrical in shape and the bodys rotation is synchronous with its orbit, the secondary will experience the BYORP effect. BYORP can cause secular motion such as the semi-major axis of the secondary expanding or contracting. Assuming the secondary expands due to BYORP, the secondary will eventually reach the unstable region of the Laplace plane. The unstable region exists if the primary has an obliquity of 68.875 degrees or greater. The unstable region exists at 0.9 Laplace radius to 1.25 Laplace radius, where the Laplace radius is defined as the distance from the central body where the inclination of the Laplace plane orbit is half the obliquity. In the unstable region, the eccentricity of the orbit

  3. Binaries and distances

    NASA Astrophysics Data System (ADS)

    Pourbaix, D.; Arenou, F.; Halbwachs, J.-L.; Siopis, C.

    2013-02-01

    Gaia's five-year observation baseline might naively lead to the expectation that it will be possible to fit the parallax of any sufficiently nearby object with the default five-parameter model (position at a reference epoch, parallax and proper motion). However, simulated Gaia observations of a `model Universe' composed of nearly 107 objects, 50% of which turn out to be multiple stars, show that the single-star hypothesis can severely affect parallax estimation and that more sophisticated models must be adopted. In principle, screening these spurious single-star solutions is rather straightforward, for example by evaluating the quality of the fits. However, the simulated Gaia observations also reveal that some seemingly acceptable single-star solutions can nonetheless lead to erroneous distances. These solutions turn out to be binaries with an orbital period close to one year. Without auxiliary (e.g., spectroscopic) data, they will remain unnoticed.

  4. VLSI binary updown counter

    NASA Technical Reports Server (NTRS)

    Truong, Trieu-Kie (Inventor); Hsu, In-Shek (Inventor); Reed, Irving S. (Inventor)

    1989-01-01

    A pipeline binary updown counter is comprised of simple stages that may be readily replicated. Each stage is defined by the Boolean logic equation: A(sub n)(t) = A(sub n)(t - 1) exclusive OR (U AND P(sub n)) inclusive OR (D AND Q(sub n)), where A(sub n)(t) denotes the value of the nth bit at time t. The input to the counter has three values represented by two binary signals U and D such that if both are zero, the input is zero, if U = 0 and D = 1, the input is -1 and if U = 1 and D = 0, the input is +1. P(sub n) represents a product of A(sub k)'s for 1 is less than or equal to k is less than or equal to -1, while Q(sub n) represents the product of bar A's for 1 is less than or equal to K is less than or equal to n - 1, where bar A(sub k) is the complement of A(sub k) and P(sub n) and Q(sub n) are expressed as the following two equations: P(sub n) = A(sub n - 1) A(sub n - 2)...A(sub 1) and Q(sub n) = bar A(sub n - 1) bar A(sub n - 2)...bar A(sub 1), which can be written in recursive form as P(sub n) = P(sub n - 1) AND bar A(sub n - 1) and Q(sub n) = Q(sub n - 1) AND bar A(sub n - 1) with the initial values P(sub 1) = 1 and Q(sub 1) = 1.

  5. Small molecule detection by lateral flow strips via aptamer-gated silica nanoprobes.

    PubMed

    Özalp, V Cengiz; Çam, Dilek; Hernandez, Frank J; Hernandez, Luiza I; Schäfer, Thomas; Öktem, Hüseyin A

    2016-04-21

    A fast, sensitive and ratiometric biosensor strategy for small molecule detection was developed through nanopore actuation. The new platform engineers together, a highly selective molecular recognition element, aptamers, and a novel signal amplification mechanism, gated nanopores. As a proof of concept, aptamer gated silica nanoparticles have been successfully used as a sensing platform for the detection of ATP concentrations at a wide linear range from 100 μM up to 2 mM. PMID:27041474

  6. PULSAR BINARY BIRTHRATES WITH SPIN-OPENING ANGLE CORRELATIONS

    SciTech Connect

    O'Shaughnessy, Richard; Kim, Chunglee E-mail: ckim@astro.lu.s

    2010-05-20

    One ingredient in an empirical birthrate estimate for pulsar binaries is the fraction of sky subtended by the pulsar beam: the pulsar beaming fraction. This fraction depends on both the pulsar's opening angle and the misalignment angle between its spin and magnetic axes. The current estimates for pulsar binary birthrates are based on an average value of beaming fractions for only two pulsars, i.e., PSRs B1913+16 and B1534+12. In this paper, we revisit the observed pulsar binaries to examine the sensitivity of birthrate predictions to different assumptions regarding opening angle and alignment. Based on empirical estimates for the relative likelihood of different beam half-opening angles and misalignment angles between the pulsar rotation and magnetic axes, we calculate an effective beaming correction factor, f{sub b,eff}, whose reciprocal is equivalent to the average fraction of all randomly selected pulsars that point toward us. For those pulsars without any direct beam geometry constraints, we find that f{sub b,eff} is likely to be smaller than 6, a canonically adopted value when calculating birthrates of Galactic pulsar binaries. We calculate f{sub b,eff} for PSRs J0737-3039A and J1141-6545, applying the currently available constraints for their beam geometry. As in previous estimates of the posterior probability density function P(R) for pulsar binary birthrates R, PSRs J0737-3039A and J1141-6545 still significantly contribute to, if not dominate, the Galactic birthrate of tight pulsar-neutron star (NS) and pulsar-white dwarf (WD) binaries, respectively. Our median posterior present-day birthrate predictions for tight PSR-NS binaries, wide PSR-NS binaries, and tight PSR-WD binaries given a preferred pulsar population model and beaming geometry are 89 Myr{sup -1}, 0.5 Myr{sup -1}, and 34 Myr{sup -1}, respectively. For long-lived PSR-NS binaries, these estimates include a weak (x1.6) correction for slowly decaying star formation in the galactic disk. For pulsars

  7. Investigations of percutaneous uptake of ultrafine TiO 2 particles at the high energy ion nanoprobe LIPSION

    NASA Astrophysics Data System (ADS)

    Menzel, F.; Reinert, T.; Vogt, J.; Butz, T.

    2004-06-01

    Micronised TiO 2 particles with a diameter of about 15 nm are used in sunscreens as physical UV filter. Due to the small particle size it may be supposed that TiO 2 particles can pass through the uppermost horny skin layer ( stratum corneum) via intercellular channels and penetrate into deeper vital skin layers. Accumulations of TiO 2 particles in the skin can decrease the threshold for allergies of the immune system or cause allergic reactions directly. Spatially resolved ion beam analysis (PIXE, RBS, STIM and secondary electron imaging) was carried out on freeze-dried cross-sections of biopsies of pig skin, on which four different formulations containing TiO 2 particles were applied. The investigations were carried out at the high energy ion nanoprobe LIPSION in Leipzig with a 2.25 MeV proton beam, which was focused to a diameter of 1 μm. The analysis concentrated on the penetration depth and on pathways of the TiO 2 particles into the skin. In these measurements a penetration of TiO 2 particles through the s. corneum into the underlying stratum granulosum via intercellular space was found. Hair follicles do not seem to be important penetration pathways because no TiO 2 was detected inside. The TiO 2 particle concentration in the stratum spinosum was below the minimum detection limit of about 1 particle/μm 2. These findings show the importance of coating the TiO 2 particles in order to prevent damage of RNA and DNA of skin cells by photocatalytic reactions of the penetrated particles caused by absorption of UV light.

  8. A homogenous fluorescence quenching based assay for specific and sensitive detection of influenza virus A hemagglutinin antigen.

    PubMed

    Chen, Longyan; Neethirajan, Suresh

    2015-01-01

    Influenza pandemics cause millions of deaths worldwide. Effective surveillance is required to prevent their spread and facilitate the development of appropriate vaccines. In this study, we report the fabrication of a homogenous fluorescence-quenching-based assay for specific and sensitive detection of influenza virus surface antigen hemagglutinins (HAs). The core of the assay is composed of two nanoprobes namely the glycan-conjugated highly luminescent quantum dots (Gly-QDs), and the HA-specific antibody-modified gold nanoparticle (Ab-Au NPs). When exposed to strain-specific HA, a binding event between the HA and the two nanoprobes takes place, resulting in the formation of a sandwich complex which subsequently brings the two nanoprobes closer together. This causes a decrease in QDs fluorescence intensity due to a non-radiative energy transfer from QDs to Au NPs. A resulting correlation between the targets HA concentrations and fluorescence changes can be observed. Furthermore, by utilizing the specific interaction between HA and glycan with sialic acid residues, the assay is able to distinguish HAs originated from viral subtypes H1 (human) and H5 (avian). The detection limits in solution are found to be low nanomolar and picomolar level for sensing H1-HA and H5-HA, respectively. Slight increase in assay sensitivity was found in terms of detection limit while exposing the assay in the HA spiked in human sera solution. We believe that the developed assay could serve as a feasible and sensitive diagnostic tool for influenza virus detection and discrimination, with further improvement on the architectures. PMID:25884789

  9. A Homogenous Fluorescence Quenching Based Assay for Specific and Sensitive Detection of Influenza Virus A Hemagglutinin Antigen

    PubMed Central

    Chen, Longyan; Neethirajan, Suresh

    2015-01-01

    Influenza pandemics cause millions of deaths worldwide. Effective surveillance is required to prevent their spread and facilitate the development of appropriate vaccines. In this study, we report the fabrication of a homogenous fluorescence-quenching-based assay for specific and sensitive detection of influenza virus surface antigen hemagglutinins (HAs). The core of the assay is composed of two nanoprobes namely the glycan-conjugated highly luminescent quantum dots (Gly-QDs), and the HA-specific antibody-modified gold nanoparticle (Ab-Au NPs). When exposed to strain-specific HA, a binding event between the HA and the two nanoprobes takes place, resulting in the formation of a sandwich complex which subsequently brings the two nanoprobes closer together. This causes a decrease in QDs fluorescence intensity due to a non-radiative energy transfer from QDs to Au NPs. A resulting correlation between the targets HA concentrations and fluorescence changes can be observed. Furthermore, by utilizing the specific interaction between HA and glycan with sialic acid residues, the assay is able to distinguish HAs originated from viral subtypes H1 (human) and H5 (avian). The detection limits in solution are found to be low nanomolar and picomolar level for sensing H1-HA and H5-HA, respectively. Slight increase in assay sensitivity was found in terms of detection limit while exposing the assay in the HA spiked in human sera solution. We believe that the developed assay could serve as a feasible and sensitive diagnostic tool for influenza virus detection and discrimination, with further improvement on the architectures. PMID:25884789

  10. Estimating neighborhood variability with a binary comparison matrix.

    USGS Publications Warehouse

    Murphy, D.L.

    1985-01-01

    A technique which utilizes a binary comparison matrix has been developed to implement a neighborhood function for a raster format data base. The technique assigns an index value to the center pixel of 3- by 3-pixel neighborhoods. The binary comparison matrix provides additional information not found in two other neighborhood variability statistics; the function is sensitive to both the number of classes within the neighborhood and the frequency of pixel occurrence in each of the classes. Application of the function to a spatial data base from the Kenai National Wildlife Refuge, Alaska, demonstrates 1) the numerical distribution of the index values, and 2) the spatial patterns exhibited by the numerical values. -Author

  11. BINARIES AMONG DEBRIS DISK STARS

    SciTech Connect

    Rodriguez, David R.; Zuckerman, B.

    2012-02-01

    We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25% {+-} 4% of our debris disk systems are binary or triple star systems, substantially less than the expected {approx}50%. The period distribution for these suggests a relative lack of systems with 1-100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1-100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk.

  12. Near-infrared fluorescence nanoprobe for enzyme-substrate system sensing and in vitro imaging.

    PubMed

    Yan, Xu; Hu, Tianyu; Wang, Lei; Zhang, Lening; Su, Xingguang

    2016-05-15

    Herein we report a simple and sensitive fluorescent sensing platform for phenol and enzyme activity detection based on 3-aminobenzeneboronic acid functionalized CuInS2 QDs (APBA-CuInS2 QDs). APBA were covalently linked to CuInS2 QDs surface to form the APBA-CuInS2 QDs which had a fairly symmetric fluorescence emission peak at 736nm in the near-infrared spectral region. In the presence of tyrosinase, phenol can be catalyzed the oxidization into catechol, which could reactive toward the boronic acid functional groups of APBA-CuInS2 QDs to form five-membered cyclic esters, leading to the fluorescence quenching of the QDs. The effective fluorescence quenching of APBA-CuInS2 QDs by phenol enabled this proposed nanosensor to sensitively detect the phenol product-related enzyme system, such as acid phosphatase-catalyzed hydrolysis of phenyl phosphate. Thus, the proposed biosensor was utilized for facile, sensitive, and selective detection phenol, tyrosinase and acid phosphatase. The detection limits of phenol, tyrosinase and acid phosphatase reached 0.05μmolL(-1), 0.03UmL(-1) and 6nUmL(-1) for, respectively. The feasibility of the proposed nanosensor in real samples assay was also studied and satisfactory results were obtained. Meanwhile, using the APBA-CuInS2 QDs fluorescence probe, we successfully performed in vitro imaging of human prostate cancer cells, suggesting the biocompatible sensor has potentially extensive application clinic diagnoses assays. PMID:26802574

  13. BDB: The Binary Star Database

    NASA Astrophysics Data System (ADS)

    Dluzhnevskaya, O.; Kaygorodov, P.; Kovaleva, D.; Malkov, O.

    2014-05-01

    Description of the Binary star DataBase (BDB, http://bdb.inasan.ru), the world's principal database of binary and multiple systems of all observational types, is presented in the paper. BDB contains data on physical and positional parameters of 100,000 components of 40,000 systems of multiplicity 2 to 20, belonging to various observational types: visual, spectroscopic, eclipsing, etc. Information on these types of binaries is obtained from heterogeneous sources of data - astronomical and. Organization of the information is based on the careful cross-identification of the objects. BDB can be queried by star identifier, coordinates, and other parameters.

  14. Lab on fiber technology: a versatile fabrication path for optimized nanoprobes

    NASA Astrophysics Data System (ADS)

    Quero, G.; Consales, M.; Crescitelli, A.; Ricciardi, A.; Esposito, E.; Cutolo, A.; Cusano, A.

    2013-05-01

    We recently introduced a reliable fabrication process enabling the integration of dielectric and metallic nanostructures directly on the tip of optical fibers1. It involves conventional deposition and nanopatterning techniques (typically used for planar devices fabrication) suitably adapted to directly operate on the fiber tip. By using this approach, and with a view towards possible applications, here we demonstrate the realization of different technological platforms based on the integration on the fiber facet of periodic and quasi-periodic metallo-dielectric nanostructures supporting localized surface plasmon resonances, that can be used for chemical and biological sensing as well as polarization sensitive devices.

  15. Multifunctional nanoprobe to enhance the utility of optical based imaging techniques

    NASA Astrophysics Data System (ADS)

    Jung, Yeongri; Guan, Guangying; Wei, Chen-Wei; Reif, Roberto; Gao, Xiaohu; O'Donnell, Matthew; Wang, Ruikang K.

    2012-01-01

    Several imaging modalities such as optical coherence tomography, photothermal, photoacoustic and magnetic resonance imaging, are sensitive to different physical properties (i.e. scattering, absorption and magnetic) that can provide contrast within biological tissues. Usually exogenous agents are designed with specific properties to provide contrast for these imaging methods. In nano-biotechnology there is a need to combine several of these properties into a single contrast agent. This multifunctional contrast agent can then be used by various imaging techniques simultaneously or can be used to develop new imaging modalities. We reported and characterized a multifunctional nanoparticle, made from gold nanoshells, which exhibits scattering, photothermal, photoacoustic, and magnetic properties.

  16. Graphene quantum dots: Highly active bifunctional nanoprobes for nonenzymatic photoluminescence detection of hydroquinone.

    PubMed

    He, Yuezhen; Sun, Jian; Feng, Dexiang; Chen, Hongqi; Gao, Feng; Wang, Lun

    2015-12-15

    In this paper, a simple and sensitive photoluminescence method is developed for the hydroquinone quantitation by using graphene quantum dots which simultaneously serve as a peroxidase-mimicking catalyst and a photoluminescence indicator. In the presence of dissolved oxygen, graphene quantum dots with intrinsic peroxidase-mimicking catalytic activity can catalyze the oxidation of hydroquinone to produce p-benzoquinone, an intermediate, which can efficiently quench graphene quantum dots' photoluminescence. Based on this effect, a novel fluorescent platform is proposed for the sensing of hydroquinone, and the detection limit of 5 nM is found. PMID:26164014

  17. Multifunctional nanoprobe to enhance the utility of optical based imaging techniques.

    PubMed

    Jung, Yeongri; Guan, Guangying; Wei, Chen-Wei; Reif, Roberto; Gao, Xiaohu; O'Donnell, Matthew; Wang, Ruikang K

    2012-01-01

    Several imaging modalities such as optical coherence tomography, photothermal, photoacoustic and magnetic resonance imaging, are sensitive to different physical properties (i.e. scattering, absorption and magnetic) that can provide contrast within biological tissues. Usually exogenous agents are designed with specific properties to provide contrast for these imaging methods. In nano-biotechnology there is a need to combine several of these properties into a single contrast agent. This multifunctional contrast agent can then be used by various imaging techniques simultaneously or can be used to develop new imaging modalities. We reported and characterized a multifunctional nanoparticle, made from gold nanoshells, which exhibits scattering, photothermal, photoacoustic, and magnetic properties. PMID:22352665

  18. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  19. Stability of binaries. Part II: Rubble-pile binaries

    NASA Astrophysics Data System (ADS)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  20. Nanomaterial-based optical sensors for sensitive detection of heavy metal ions

    NASA Astrophysics Data System (ADS)

    Wang, Shasha; Chen, Lingxin

    2015-07-01

    Nanometerial-based optical nanoprobes have been extensively developed because of their high sensitivity, good specificity, and potential for easy quantification of species in chemical and biological analysis. With the development of nanotechnology, various kinds of nanomaterials with novel optical properties have heen generated, laying the foundation of optical nanoprobes. By further integrating receptors (chemical ligand, aptamer, molecular imprinting polymer, etc.), the information of binding specific targets will transform into analytically optical signals by employing different detection techniques including colorimetry/UV-Vis spectra, fluorometry and surface enhanced Raman scattering (SERS). In this presentation, firstly, we introduced a simple, rapid and ultrasensitive SERS nanosensor for mercury ion (Hg2+) detection based on the 4-mercaptopyridine (4-MPY) functionalized silver nanoparticles (AgNPs) in the presence of spermine; then, a novel colorimetric nanosensor for mercury species was developed for the first time due to the analyte-induced aggregation of gold nanoparticles (AuNPs) with the assistance of a thiol-containing ligand of diethyldithiocarbamate (DDTC); finally, the sensitive and selective recognition and detection of trypsin was realized in a SERS strategy by using anti-aggregation of 4-MPY-functionalized AgNPs on the basis of the interaction between protamine and trypsin.

  1. Cryptography with DNA binary strands.

    PubMed

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'. PMID:10963862

  2. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    SciTech Connect

    Shevchenko, Ivan I.

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  3. An adaptable binary entropy coder

    NASA Technical Reports Server (NTRS)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  4. Simulating relativistic binaries with Whisky

    NASA Astrophysics Data System (ADS)

    Baiotti, L.

    We report about our first tests and results in simulating the last phase of the coalescence and the merger of binary relativistic stars. The simulations were performed using our code Whisky and mesh refinement through the Carpet driver.

  5. From wide to close binaries?

    NASA Astrophysics Data System (ADS)

    Eggleton, Peter P.

    The mechanisms by which the periods of wide binaries (mass 8 solar mass or less and period 10-3000 d) are lengthened or shortened are discussed, synthesizing the results of recent theoretical investigations. A system of nomenclature involving seven evolutionary states, three geometrical states, and 10 types of orbital-period evolution is developed and applied; classifications of 71 binaries are presented in a table along with the basic observational parameters. Evolutionary processes in wide binaries (single-star-type winds, magnetic braking with tidal friction, and companion-reinforced attrition), late case B systems, low-mass X-ray binaries, and triple systems are examined in detail, and possible evolutionary paths are shown in diagrams.

  6. Achieving Stability Requirements for Nanoprobe and Long Beam Lines at NSLS II. A Comprehensive Study

    SciTech Connect

    Simos,N.; Fallier, M.; Hill, J.; Berman, L.; Evans-Lutterodt, K.; Broadbent, A.

    2008-06-23

    Driven by beam stability requirements at the NSLS II synchrotron, such that the desired small beam sizes and high brightness are both realized and stable, a comprehensive study has been launched seeking to provide assurances that stability at the nanometer level at critical x-ray beam-lines, is achievable, given the natural and cultural vibration environment at the selected site. The study consists of (a) an extensive investigation of the site to evaluate the existing ground vibration, in terms of amplitude, frequency content and coherence, and (b) of a numerical study of wave propagation and interaction with the infrastructure of the sensitive lines. The paper presents results from both aspects of the study.

  7. Ultraviolet spectroscopy of binary systems

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.; Hartmann, L.; Raymond, J. C.

    1980-01-01

    Four typical binary systems that illustrate some of the major problems in the study of binary stars are discussed. Consideration is given to (1) high-luminosity X-ray sources typified by Cyg X-1 (HDE 226868) and Vela XR-1 (HD 77581), (2) low-luminosity X-ray sources (HZ Her), (3) late-type systems of W UMa and RS CVn type, and (4) cool supergiants with a hot companion (VV Cephei).

  8. Binary Properties from Cepheid Radial Velocities (CRaV)

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Remage; Berdnikov, Leonid; Lauer, Jennifer; Morgan, Douglas; Nichols, Joy; Günther, H. Moritz; Gorynya, Natalya; Rastorguev, Alexey; Moskalik, Pawel

    2015-07-01

    We have examined high accuracy radial velocities of Cepheids to determine the binary frequency. The data are largely from the CORAVEL spectrophotometer and the Moscow version, with a typical uncertainty of ≤slant 1 km s-1, and a time span from 1 to 20 years. A systemic velocity was obtained by removing the pulsation component using a high order Fourier series. From this data we have developed a list of stars showing no orbital velocity larger than ±1 km s-1. The binary fraction was analyzed as a function of magnitude, and yields an apparent decrease in this fraction for fainter stars. We interpret this as incompleteness at fainter magnitudes, and derive the preferred binary fraction of 29% ± 8% (20% ± 6% per decade of orbital period) from the brightest 40 stars. A comparison of this fraction in this period range (1-20 years) implies a large fraction for the full period range. This is reasonable in that the high accuracy velocities are sensitive to the longer periods and smaller orbital velocity amplitudes in the period range sampled here. Thus the Cepheid velocity sample provides a sensitive detection in the period range between short period spectroscopic binaries and resolved companions. The recent identification of δ Cep as a binary with very low amplitude and high eccentricity underscores the fact that the binary fractions we derive are lower limits, to which other low amplitude systems will probably be added. The mass ratio (q) distribution derived from ultraviolet observations of the secondary is consistent with a flat distribution for the applicable period range (1-20 years).

  9. TRIPLE-STAR CANDIDATES AMONG THE KEPLER BINARIES

    SciTech Connect

    Rappaport, S.; Deck, K.; Sanchis-Ojeda, R.; Levine, A.; Borkovits, T.; Carter, J.; El Mellah, I.; Kalomeni, B. E-mail: kdeck@mit.edu E-mail: aml@space.mit.edu E-mail: jacarter@cfa.harvard.edu

    2013-05-01

    We present the results of a search through the photometric database of Kepler eclipsing binaries looking for evidence of hierarchical triple-star systems. The presence of a third star orbiting the binary can be inferred from eclipse timing variations. We apply a simple algorithm in an automated determination of the eclipse times for all 2157 binaries. The ''calculated'' eclipse times, based on a constant period model, are subtracted from those observed. The resulting O - C (observed minus calculated times) curves are then visually inspected for periodicities in order to find triple-star candidates. After eliminating false positives due to the beat frequency between the {approx}1/2 hr Kepler cadence and the binary period, 39 candidate triple systems were identified. The periodic O - C curves for these candidates were then fit for contributions from both the classical Roemer delay and so-called physical delay, in an attempt to extract a number of the system parameters of the triple. We discuss the limitations of the information that can be inferred from these O - C curves without further supplemental input, e.g., ground-based spectroscopy. Based on the limited range of orbital periods for the triple-star systems to which this search is sensitive, we can extrapolate to estimate that at least 20% of all close binaries have tertiary companions.

  10. Triple-star Candidates among the Kepler Binaries

    NASA Astrophysics Data System (ADS)

    Rappaport, S.; Deck, K.; Levine, A.; Borkovits, T.; Carter, J.; El Mellah, I.; Sanchis-Ojeda, R.; Kalomeni, B.

    2013-05-01

    We present the results of a search through the photometric database of Kepler eclipsing binaries looking for evidence of hierarchical triple-star systems. The presence of a third star orbiting the binary can be inferred from eclipse timing variations. We apply a simple algorithm in an automated determination of the eclipse times for all 2157 binaries. The "calculated" eclipse times, based on a constant period model, are subtracted from those observed. The resulting O - C (observed minus calculated times) curves are then visually inspected for periodicities in order to find triple-star candidates. After eliminating false positives due to the beat frequency between the ~1/2 hr Kepler cadence and the binary period, 39 candidate triple systems were identified. The periodic O - C curves for these candidates were then fit for contributions from both the classical Roemer delay and so-called physical delay, in an attempt to extract a number of the system parameters of the triple. We discuss the limitations of the information that can be inferred from these O - C curves without further supplemental input, e.g., ground-based spectroscopy. Based on the limited range of orbital periods for the triple-star systems to which this search is sensitive, we can extrapolate to estimate that at least 20% of all close binaries have tertiary companions.

  11. A direct detection of Escherichia coli genomic DNA using gold nanoprobes

    PubMed Central

    2012-01-01

    Background In situation like diagnosis of clinical and forensic samples there exists a need for highly sensitive, rapid and specific DNA detection methods. Though conventional DNA amplification using PCR can provide fast results, it is not widely practised in diagnostic laboratories partially because it requires skilled personnel and expensive equipment. To overcome these limitations nanoparticles have been explored as signalling probes for ultrasensitive DNA detection that can be used in field applications. Among the nanomaterials, gold nanoparticles (AuNPs) have been extensively used mainly because of its optical property and ability to get functionalized with a variety of biomolecules. Results We report a protocol for the use of gold nanoparticles functionalized with single stranded oligonucleotide (AuNP- oligo probe) as visual detection probes for rapid and specific detection of Escherichia coli. The AuNP- oligo probe on hybridization with target DNA containing complementary sequences remains red whereas test samples without complementary DNA sequences to the probe turns purple due to acid induced aggregation of AuNP- oligo probes. The color change of the solution is observed visually by naked eye demonstrating direct and rapid detection of the pathogenic Escherichia coli from its genomic DNA without the need for PCR amplification. The limit of detection was ~54 ng for unamplified genomic DNA. The method requires less than 30 minutes to complete after genomic DNA extraction. However, by using unamplified enzymatic digested genomic DNA, the detection limit of 11.4 ng was attained. Results of UV-Vis spectroscopic measurement and AFM imaging further support the hypothesis of aggregation based visual discrimination. To elucidate its utility in medical diagnostic, the assay was validated on clinical strains of pathogenic Escherichia coli obtained from local hospitals and spiked urine samples. It was found to be 100% sensitive and proves to be highly specific without

  12. Optimal dye-quencher pairs for the design of an "activatable" nanoprobe for optical imaging.

    PubMed

    Simard, Bryan; Tomanek, Boguslaw; van Veggel, Frank C J M; Abulrob, Abedelnasser

    2013-10-01

    Optical imaging offers high sensitivity and portability at low cost. The design of an optimal "activatable" imaging agent could greatly decrease the background noise and increase specificity of the signal. Five different molecules have been used to quench basal fluorescence of an enzyme substrate labeled with Cy5, Cy5.5 or IR800 at a distance of 8 amino acids (32 Å): a 6 nm gold nanoparticle (NP), a 20 nm and a 30 nm iron oxide (FeO) NP, the black hole quencher BHQ-3 and the IRdye quencher QC-1. The quenching efficiencies were 99% for QC1-IR800, 98% for QC1-Cy5.5, 96% for 30 nm FeO NP-Cy5.5, 89% for BHQ3-Cy5, 84% for BHQ3-Cy5.5, 77-90% for 6 nm gold NP-Cy5.5, depending on the number of dyes around the NP, 79% for 20 nm FeO NP-Cy5.5 and 77% for Cy5.5-Cy5. Signal activation upon cleavage by the matrix metalloproteinase MMP9 was proportional to the quenching efficiencies, ranging from 3-fold with Cy5.5-Cy5 to 67-fold with QC1-IR800. This independent work reports on the properties of the dyes and quenchers explaining the superior performance of QC-1 and 30 nm FeO NPs. PMID:23892541

  13. Planets in Evolved Binary Systems

    NASA Astrophysics Data System (ADS)

    Perets, Hagai B.

    2011-03-01

    Exo-planets are typically thought to form in protoplanetary disks left over from protostellar disk of their newly formed host star. However, additional planetary formation and evolution routes may exist in old evolved binary systems. Here we discuss the implications of binary stellar evolution on planetary systems in such environments. In these binary systems stellar evolution could lead to the formation of symbiotic stars, where mass is lost from one star and could be transferred to its binary companion, and may form an accretion disk around it. This raises the possibility that such a disk could provide the necessary environment for the formation of a new, second generation of planets in both circumstellar or circumbinary configurations. Pre-existing first generation planets surviving the post-MS evolution of such systems would be dynamically effected by the mass loss in the systems and may also interact with the newly formed disk. Such planets and/or planetesimals may also serve as seeds for the formation of the second generation planets, and/or interact with them, possibly forming atypical planetary systems. Second generation planetary systems should be typically found in white dwarf binary systems, and may show various observational signatures. Most notably, second generation planets could form in environment which are inaccessible, or less favorable, for first generation planets. The orbital phase space available for the second generation planets could be forbidden (in terms of the system stability) to first generation planets in the pre-evolved progenitor binaries. In addition planets could form in metal poor environments such as globular clusters and/or in double compact object binaries. Observations of exo-planets in such forbidden or unfavorable regions could possibly serve to uniquely identify their second generation character. Finally, we point out a few observed candidate second generation planetary systems, including Gl 86, HD 27442 and all of the

  14. OmpF, a nucleotide-sensing nanoprobe, computational evaluation of single channel activities

    NASA Astrophysics Data System (ADS)

    Abdolvahab, R. H.; Mobasheri, H.; Nikouee, A.; Ejtehadi, M. R.

    2016-09-01

    The results of highthroughput practical single channel experiments should be formulated and validated by signal analysis approaches to increase the recognition precision of translocating molecules. For this purpose, the activities of the single nano-pore forming protein, OmpF, in the presence of nucleotides were recorded in real time by the voltage clamp technique and used as a means for nucleotide recognition. The results were analyzed based on the permutation entropy of current Time Series (TS), fractality, autocorrelation, structure function, spectral density, and peak fraction to recognize each nucleotide, based on its signature effect on the conductance, gating frequency and voltage sensitivity of channel at different concentrations and membrane potentials. The amplitude and frequency of ion current fluctuation increased in the presence of Adenine more than Cytosine and Thymine in milli-molar (0.5 mM) concentrations. The variance of the current TS at various applied voltages showed a non-monotonic trend whose initial increasing slope in the presence of Thymine changed to a decreasing one in the second phase and was different from that of Adenine and Cytosine; e.g., by increasing the voltage from 40 to 140 mV in the 0.5 mM concentration of Adenine or Cytosine, the variance decreased by one third while for the case of Thymine it was doubled. Moreover, according to the structure function of TS, the fractality of current TS differed as a function of varying membrane potentials (pd) and nucleotide concentrations. Accordingly, the calculated permutation entropy of the TS, validated the biophysical approach defined for the recognition of different nucleotides at various concentrations, pd's and polarities. Thus, the promising outcomes of the combined experimental and theoretical methodologies presented here can be implemented as a complementary means in pore-based nucleotide recognition approaches.

  15. The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy.

    PubMed

    Sancey, L; Lux, F; Kotb, S; Roux, S; Dufort, S; Bianchi, A; Crémillieux, Y; Fries, P; Coll, J-L; Rodriguez-Lafrasse, C; Janier, M; Dutreix, M; Barberi-Heyob, M; Boschetti, F; Denat, F; Louis, C; Porcel, E; Lacombe, S; Le Duc, G; Deutsch, E; Perfettini, J-L; Detappe, A; Verry, C; Berbeco, R; Butterworth, K T; McMahon, S J; Prise, K M; Perriat, P; Tillement, O

    2014-09-01

    A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed. PMID:24990037

  16. The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy

    PubMed Central

    Sancey, L; Kotb, S; Roux, S; Dufort, S; Bianchi, A; Crémillieux, Y; Fries, P; Coll, J-L; Rodriguez-Lafrasse, C; Janier, M; Dutreix, M; Barberi-Heyob, M; Boschetti, F; Denat, F; Louis, C; Porcel, E; Lacombe, S; Le Duc, G; Deutsch, E; Perfettini, J-L; Detappe, A; Verry, C; Berbeco, R; Butterworth, K T; McMahon, S J; Prise, K M; Perriat, P; Tillement, O

    2014-01-01

    A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed. PMID:24990037

  17. Graphene-Rhodamine Nanoprobe for Colorimetric and Fluorimetric Hg(2+) Ion Assay.

    PubMed

    Mohan, Anju; Neeroli Kizhakayil, Renuka

    2016-06-01

    This article reveals the first ever prospective application of Graphene-Rhodamine array (GRH) as a colorimetric and fluorimetric sensor for Hg(2+) ions. The duality of Graphene to undergo π-π and dispersive interactions with Rhodamine as well as to act as a selective adsorbent for Hg(2+) is conceptualized in this study. These interactions lead to decrease in absorbance of the dye in the presence of graphene, which is restored when kept in contact with Hg(2+) ions. The feasibility of the mechanism has been proved using EDTA as the coordinating ligand. It is noteworthy that all the optical variations occurred in the visible scale of the electromagnetic spectrum. The GRH array exhibited higher sensitivity toward the target ion with a limit of detection of 2 ppb. A perfect linear variation of absorbance at 554 nm with Hg(2+) concentration was observed in 0-1000 nM range, enabling the use of the system as a quantitative sensor for the test ion. The commendable selectivity of the array toward Hg(2+) ion has been investigated by observing the optical response in the presence of other environmentally relevant metal ions. A reversible turn off and turn on INHIBIT logic gate has been proposed which extends the scope of the designed array for the development of automated chemical systems. The fluorescence resonance energy transfer (FRET) ability of graphene paves the backbone for the fluorimetric detection. Fluorimetric strategy yielded a much lower limit of detection of 380 ppt using this probe, which makes a significant advance in trace detection of Hg(2+) ions. PMID:27195915

  18. Ultra--Low-Frequency Gravitational Radiation from Massive Black Hole Binaries

    NASA Astrophysics Data System (ADS)

    Rajagopal, Mohan; Romani, Roger W.

    1995-06-01

    For massive black hole binaries produced in galactic mergers, we examine the possibility of inspiral induced by interaction with field stars. We model the evolution of such binaries for a range of galaxy core and binary parameters, using numerical results from the literature to compute the binary's energy and angular momentum loss rates due to stellar encounters and including the effect of back-action on the field stars. We find that only a small fraction of binary systems can merge within a Hubble time via unassisted stellar dynamics. External perturbations may, however, cause efficient inspiral. Averaging over a population of central black holes and galaxy mergers, we computed the expected background of gravitational radiation with periods Pw ˜ 1-10 yr. Comparison with sensitivities from millisecond pulsar timing suggests that the strongest sources may be detectable with modest improvements to present experiments.

  19. Are All Dwarf Carbon Stars Binary?

    NASA Astrophysics Data System (ADS)

    Farihi, Jay; Harris, Hugh; Subasavage, John; Bergfors, Carolina; Green, Paul; Gansicke, Boris

    2014-08-01

    The origin of dwarf carbon stars is a persistent astrophysical curiosity dating back to 1977. Only giant stars dredge up interior carbon, and hence the discovery of an unevolved dwarf star with C/O >1 was a big surprise. Astronomers are no closer to understanding these rare and spectrally peculiar stars 37 years later(!). The bulk of dwarf carbon stars show no sign of an evolved companion necessary to account for their externally polluted atmospheres. These stars are sensitive tracers of Galactic chemical evolution and star formation, and provide strong constraints on the potential for carbon-dominated (single star) planetary systems. We propose to conclusively validate or refute the hypothetical binary nature of dwarf carbon stars, and hence their chemical and physical formation channel(s). For all binaries, we will initially constrain and eventually measure orbital periods. By determining their physical separation during the previous epoch of mass transfer, we will distinguish between the Roche lobe overflow and wind capture models for the creation of carbon dwarfs.

  20. A Sandwich Electrochemical Immunosensor Using Magnetic DNA Nanoprobes for Carcinoembryonic Antigen

    PubMed Central

    Gan, Ning; Jia, Liyong; Zheng, Lei

    2011-01-01

    A novel magnetic nanoparticle-based electrochemical immunoassay of carcinoembryonic antigen (CEA) was designed as a model using CEA antibody-functionalized magnetic beads [DNA/Fe3O4/ZrO2; Fe3O4 (core)/ZrO2 (shell) nano particles (ZMPs)] as immunosensing probes. To design the immunoassay, the CEA antibody and O-phenylenediamine (OPD) were initially immobilized on a chitosan/nano gold composite membrane on a glassy carbon electrode (GCE/CS-nano Au), which was used for CEA recognition. Then, horseradish peroxidase (HRP)-labeled anti-CEA antibodies (HRP-CEA Ab2) were bound to the surface of the synthesized magnetic ZMP nanoparticles as signal tag. Thus, the sandwich-type immune complex could be formed between secondary antibody (Ab2) modified DNA/ZMPs nanochains tagged by HRP and GCE/CS-nano Au. Unlike conventional nanoparticle-based electrochemical immunoassays, the recognition elements of this immunoassay included both electron mediators and enzyme labels, which obviously simplifies the electrochemical measurement process. The sandwich-type immunoassay format was used for online formation of the immunocomplex of CEA captured in the detection cell with an external magnet. The electrochemical signals derived from HRP during the reduction of H2O2 with OPD as electron mediator were measured. The method displayed a high sensitivity for CEA detection in the range of 0.008–200 ng/mL, with a detection limit of 5 pg/mL (estimated at a signal-to-noise ratio of 3). The precision, reproducibility, and stability of the immunoassay were good. The use of the assay was evaluated with clinical serum samples, and the results were in excellent accordance with those obtained using the standard enzyme-linked immunosorbent assay (ELISA) method. Thus, the magnetic nanoparticle-based assay format is a promising approach for clinical applications, and it could be further developed for the detection of other biomarkers in cancer diagnosis. PMID:22174606

  1. The Michigan Binary Star Program

    NASA Astrophysics Data System (ADS)

    Lindner, Rudi P.

    2007-07-01

    At the end of the nineteenth century, William J. Hussey and Robert G. Aitken, both at Lick Observatory, began a systematic search for unrecorded binary stars with the aid of the 12" and 36" refracting telescopes at Lick Observatory. Aitken's work (and book on binary stars) are well known, Hussey's contributions less so. In 1905 Hussey, a Michigan engineering graduate, returned to direct the Ann Arbor astronomy program, and immediately he began to design new instrumentation for the study of binary stars and to train potential observers. For a time, he spent six months a year at the La Plata Observatory, where he discovered a number of new pairs and decided upon a major southern hemisphere campaign. He spent a decade obtaining the lenses for a large refractor, through the vicissitudes of war and depression. Finally, he obtained a site in South Africa, a 26" refractor, and a small corps of observers, but he died in London en route to fulfill his dream. His right hand man, Richard Rossiter, established the observatory and spent the next thirty years discovering and measuring binary stars: his personal total is a record for the field. This talk is an account of the methods, results, and utility of the extraordinary binary star factory in the veldt.

  2. Thirty New Low-mass Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Shkolnik, Evgenya L.; Hebb, Leslie; Liu, Michael C.; Reid, I. Neill; Collier Cameron, Andrew

    2010-06-01

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P rot to determine the true orbital parameters. For those with no P rot, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems. Based on observations collected at the W. M. Keck Observatory, the Canada-France-Hawaii Telescope and by the WASP Consortium. The Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation. The CFHT is operated by the National Research Council of Canada

  3. Constraints on Inspiralling Binaries from First LWA Data

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Joanna; Gough, J.; Cutchin, S. E.; Kavic, M.; Simonetti, J. H.; Akukwe, B.; Bear, B.; Tsai, J.; Kassim, N. E.

    2014-01-01

    The merger of a binary neutron star pair is expected to generate a strong transient radio signal. This emission will be strongest at low-frequencies and will disperse as it transverses the interstellar medium, arriving at Earth after coincidentally emitted gravitational or (higher frequency) electromagnetic signals. The rate of compact object merger events is poorly constrained by observations. The first station of Long Wavelength Array (LWA-1) telescope is a low-frequency radio telescope located near Socorro, NM, which is sensitive to a frequency range of 10-88 MHz. I will discuss the sensitivity of LWA-1 to transient radio emission from binary neutron star mergers and a limit set by LWA-1 observations to constrain the rate of such merger events.

  4. Does sensitivity in binary choice tasks depend on response modality?

    PubMed

    Szumska, Izabela; van der Lubbe, Rob H J; Grzeczkowski, Lukasz; Herzog, Michael H

    2016-07-01

    In most models of vision, a stimulus is processed in a series of dedicated visual areas, leading to categorization of this stimulus, and possible decision, which subsequently may be mapped onto a motor-response. In these models, stimulus processing is thought to be independent of the response modality. However, in theories of event coding, common coding, and sensorimotor contingency, stimuli may be very specifically mapped onto certain motor-responses. Here, we compared performance in a shape localization task and used three different response modalities: manual, saccadic, and verbal. Meta-contrast masking was employed at various inter-stimulus intervals (ISI) to manipulate target visibility. Although we found major differences in reaction times for the three response modalities, accuracy remained at the same level for each response modality (and all ISIs). Our results support the view that stimulus-response (S-R) associations exist only for specific instances, such as reflexes or skills, but not for arbitrary S-R pairings. PMID:27236357

  5. Experience with parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.

    1993-01-01

    Parametric Binary Dissection (PBD) is a new algorithm that can be used for partitioning graphs embedded in 2- or 3-dimensional space. It partitions explicitly on the basis of nodes + (lambda)x(edges cut), where lambda is the ratio of time to communicate over an edge to the time to compute at a node. The new algorithm is faster than the original binary dissection algorithm and attempts to obtain better partitions than the older algorithm, which only takes nodes into account. The performance of parametric dissection with plain binary dissection on 3 large unstructured 3-d meshes obtained from computational fluid dynamics and on 2 random graphs were compared. It was showm that the new algorithm can usually yield partitions that are substantially superior, but that its performance is heavily dependent on the input data.

  6. Liquidus of Silicon Binary Systems

    NASA Astrophysics Data System (ADS)

    Safarian, Jafar; Kolbeinsen, Leiv; Tangstad, Merete

    2011-08-01

    Thermodynamic knowledge about liquid silicon is crucial for the production of solar-grade silicon feedstock from molten silicon. In the current study, liquidus for silicon binary alloys is formulated using a previously developed method in which the liquidus curve is calculated using two constants. The liquidus measurements for the silicon portion of the silicon alloys with Al, Ca, Mg, Fe, Ti, Zn, Cu, Ag, Au, Pt, Sn, Pb, Bi, Sb, Ga, In, Ni, Pd, Mn, and Rh are reviewed, and the consistent data were used to determine the liquidus constants. The liquidus curves for silicon binary systems are calculated and plotted. It is indicated that the calculated liquidus curves fit well with the experimental data. A correlation between the determined liquidus constants is also observed, which can be used to gain a better understanding of the thermodynamics of the silicon binary melts.

  7. An electrically powered binary star?

    NASA Astrophysics Data System (ADS)

    Wu, Kinwah; Cropper, Mark; Ramsay, Gavin; Sekiguchi, Kazuhiro

    2002-03-01

    We propose a model for stellar binary systems consisting of a magnetic and a non-magnetic white dwarf pair which is powered principally by electrical energy. In our model the luminosity is caused by resistive heating of the stellar atmospheres arising from induced currents driven within the binary. This process is reminiscent of the Jupiter-Io system, but greatly increased in power because of the larger companion and stronger magnetic field of the primary. Electrical power is an alternative stellar luminosity source, following on from nuclear fusion and accretion. We find that this source of heating is sufficient to account for the observed X-ray luminosity of the 9.5-min binary RX J1914+24, and provides an explanation for its puzzling characteristics.

  8. Sunflower-type nanogels carrying a quantum dot nanoprobe for both superior gene delivery efficacy and tracing of human mesenchymal stem cells.

    PubMed

    Park, Ji Sun; Yi, Se Won; Kim, Hye Jin; Kim, Seong Min; Shim, Sung Han; Park, Keun-Hong

    2016-01-01

    Sunflower-type nanogels carrying the QD 655 nanoprobe can be used for both gene transfection and bioimaging of hMSCs. The entry of sunflower-type nanogels into hMSCs can be possibly controlled by changing the formation of QDs. The physico-chemical properties of sunflower-type nanogels internalized by hMSCs were confirmed by AFM, SEM, TEM, gel retardation, and ζ-potential analyses. The bioimaging capacity was confirmed by confocal laser microscopy, Kodak imaging, and Xenogen imaging. Specifically, we investigated the cytotoxicity of sunflower-type nanogels via SNP analysis. Internalization of sunflower-type nanogels does not cause malfunction of hMSCs. PMID:26576046

  9. In vivo cancer targeting and fluorescence-CT dual-mode imaging with nanoprobes based on silver sulfide quantum dots and iodinated oil

    NASA Astrophysics Data System (ADS)

    Qin, Meng-Yao; Yang, Xiao-Quan; Wang, Kan; Zhang, Xiao-Shuai; Song, Ji-Tao; Yao, Ming-Hao; Yan, Dong-Mei; Liu, Bo; Zhao, Yuan-Di

    2015-11-01

    In this article, a fluorescence-CT dual-mode nanoprobe is successfully synthesized by making use of distearoylphosphatidylethanolamine-poly(ethylene glycol)-folate (DSPE-PEG2000-FA) and other amphiphilic molecules to coat silver sulfide (Ag2S) quantum dots (QDs) and iodinated oil simultaneously. In vitro experiments show that the fluorescence wavelength of the nanoprobe is 1170 nm in the near infrared-II region. Its size is 139.6 nm, it has good dispersibility, and it has low cellular toxicity at concentrations up to 25 μg mL-1 Ag. In vivo experiments revealed that the probe has a rather long circulation time (blood half-life of 5.7 hours), and the tissue histopathological tests show that it is not obviously harmful to major organs' normal function. Biochemical analysis (glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels) and blood analysis (white blood cell, red blood cell, hemoglobin and blood platelet counts) reveal that it has little influence on blood within 15 days of administration. When injected into HeLa xenograft nude mice by the tail vein, the probe elicited intensely enhanced fluorescence and X-ray computed tomography (CT) signals in the tumors after 24 hours, and the structure, size and position of tumor tissue were shown clearly. In a word, the probe has good tumor targeting capabilities, and it has significant value in fluorescence-CT dual-mode imaging in vivo.In this article, a fluorescence-CT dual-mode nanoprobe is successfully synthesized by making use of distearoylphosphatidylethanolamine-poly(ethylene glycol)-folate (DSPE-PEG2000-FA) and other amphiphilic molecules to coat silver sulfide (Ag2S) quantum dots (QDs) and iodinated oil simultaneously. In vitro experiments show that the fluorescence wavelength of the nanoprobe is 1170 nm in the near infrared-II region. Its size is 139.6 nm, it has good dispersibility, and it has low cellular toxicity at concentrations up to 25 μg mL-1 Ag. In vivo experiments revealed that the

  10. The Signature of Black Hole-Neutron Star Binaries

    NASA Astrophysics Data System (ADS)

    Liebling, Steven; Anderson, Matthew; Hirschmann, Eric; Lehner, Luis; Motl, Patrick; Neilsen, David; Palenzuela, Carlos

    2011-04-01

    Black hole-neutron star (BHNS) binaries are key gravitational wave sources, merging in the frequency band to which Earth-based GW detectors are most sensitive. Furthermore, as possible candidates for short-hard gamma ray bursts, combined observations in both gravitational and electromagnetic bands of BHNS mergers is thus an exciting possibility. This talk will discuss results from simulations that account for gravitational and magnetic effects as well as connections with processes capable of explaining key features of gamma ray bursts.

  11. Chandra Observation of Luminous and Ultraluminous X-ray Binaries in M101

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Pence, W. D.; Snowden, S. L.; Kuntz, K. D.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    X-ray binaries in the Milky Way are among the brightest objects on the X-ray sky. With the increasing sensitivity of recent missions, it is now possible to study X-ray binaries in nearby galaxies. We present data on six ultraluminous binaries in the nearby spiral galaxy, M101, obtained with Chandra ACIS-S. Of these, five appear to be similar to ultraluminous sources in other galaxies, while the brightest source, P098, shows some unique characteristics. We present our interpretation of the data in terms of an optically thick outflow, and discuss implications.

  12. ``Smart'' theranostic lanthanide nanoprobes with simultaneous up-conversion fluorescence and tunable T1-T2 magnetic resonance imaging contrast and near-infrared activated photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Das, Gautom Kumar; Vijayaragavan, Vimalan; Xu, Qing Chi; Padmanabhan, Parasuraman; Bhakoo, Kishore K.; Tamil Selvan, Subramanian; Tan, Timothy Thatt Yang

    2014-10-01

    The current work reports a type of ``smart'' lanthanide-based theranostic nanoprobe, NaDyF4:Yb3+/NaGdF4:Yb3+,Er3+, which is able to circumvent the up-converting poisoning effect of Dy3+ ions to give efficient near infrared (980 nm) triggered up-conversion fluorescence, and offers not only excellent dark T2-weighted MR contrast but also tunable bright and T1-weighted MR contrast properties. Due to the efficient up-converted energy transfer from the nanocrystals to chlorin e6 (Ce6) photosensitizers loaded onto the nanocrystals, cytotoxic singlet oxygen was generated and photodynamic therapy was demonstrated. Therefore, the current multifunctional nanocrystals could be potentially useful in various image-guided diagnoses where bright or dark MRI contrast could be selectively tuned to optimize image quality, but also as an efficient and more penetrative near-infrared activated photodynamic therapy agent.The current work reports a type of ``smart'' lanthanide-based theranostic nanoprobe, NaDyF4:Yb3+/NaGdF4:Yb3+,Er3+, which is able to circumvent the up-converting poisoning effect of Dy3+ ions to give efficient near infrared (980 nm) triggered up-conversion fluorescence, and offers not only excellent dark T2-weighted MR contrast but also tunable bright and T1-weighted MR contrast properties. Due to the efficient up-converted energy transfer from the nanocrystals to chlorin e6 (Ce6) photosensitizers loaded onto the nanocrystals, cytotoxic singlet oxygen was generated and photodynamic therapy was demonstrated. Therefore, the current multifunctional nanocrystals could be potentially useful in various image-guided diagnoses where bright or dark MRI contrast could be selectively tuned to optimize image quality, but also as an efficient and more penetrative near-infrared activated photodynamic therapy agent. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01717j

  13. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging.

    PubMed

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-12

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo. PMID:25716884

  14. Orbits of 15 visual binaries

    NASA Astrophysics Data System (ADS)

    Heintz, W. D.

    1981-04-01

    Micrometer observations in 1979-1980 permitted the computation of substantially revised or new orbital elements for 15 visual pairs. They include the bright stars 52 Ari and 78 UMa (in the UMa cluster), four faint dK pairs, and the probable triple ADS 16185. Ephemerides for equator of data are listed in a table along with the orbital elements of the binaries. The measured positions and their residuals are listed in a second table. The considered binaries include ADS 896, 2336, 6315, 7054, 7629, 8092, 8555, 8739, 13987, 16185, Rst 1658, 3906, 3972, 4529, and Jsp 691.

  15. Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

    SciTech Connect

    2010-04-29

    A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

  16. Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

    ScienceCinema

    None

    2011-10-06

    A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

  17. Mental Effort in Binary Categorization Aided by Binary Cues

    ERIC Educational Resources Information Center

    Botzer, Assaf; Meyer, Joachim; Parmet, Yisrael

    2013-01-01

    Binary cueing systems assist in many tasks, often alerting people about potential hazards (such as alarms and alerts). We investigate whether cues, besides possibly improving decision accuracy, also affect the effort users invest in tasks and whether the required effort in tasks affects the responses to cues. We developed a novel experimental tool…

  18. BINARY YORP EFFECT AND EVOLUTION OF BINARY ASTEROIDS

    SciTech Connect

    Steinberg, Elad; Sari, Re'em

    2011-02-15

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over {approx}10{sup 4}-10{sup 5} years for a D{sub p} = 2 km primary with a D{sub s} = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J{sub 2} effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  19. Recent Minima of 193 Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Samolyk, G.

    2016-06-01

    This paper continues the publication of times of minima for eclipsing binary stars from observations reported to the AAVSO Eclipsing Binary section. Times of minima from CCD observations received by the author from November 2015 through January 2016 are presented.

  20. Sensitive and selective detection of copper ions with highly stable polyethyleneimine-protected silver nanoclusters.

    PubMed

    Yuan, Zhiqin; Cai, Na; Du, Yi; He, Yan; Yeung, Edward S

    2014-01-01

    Copper is a highly toxic environmental pollutant with bioaccumulative properties. Therefore, sensitive Cu(2+) detection is very important to prevent over-ingestion, and visual detection using unaugmented vision is preferred for practical applications. In this study, hyperbranched polyethyleneimine-protected silver nanoclusters (hPEI-AgNCs) were successfully synthesized using a facile, one-pot reaction under mild conditions. The hPEI-AgNCs were very stable against extreme pH, ionic strength, temperature, and photoillumination and could act as sensitive and selective Cu(2+) sensing nanoprobes in aqueous solutions with a 10 nM limit of detection. In addition, hPEI-AgNCs-doped agarose hydrogels were developed as an instrument-free and regenerable platform for visual Cu(2+) and water quality monitoring. PMID:24274096

  1. Hydrodynamic Simulations of Contact Binaries

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan; Clayton, Geoffrey C.; Frank, Juhan; Marcello, Dominic; Motl, Patrick M.; Staff, Jan E.

    2015-01-01

    The motivation for our project is the peculiar case of the 'red nova" V1309 Sco which erupted in September 2008. The progenitor was, in fact, a contact binary system. We are developing a simulation of contact binaries, so that their formation, structural, and merger properties could be studied using hydrodynamics codes. The observed transient event was the disruption of the secondary star by the primary, and their subsequent merger into one star; hence to replicate this behavior, we need a core-envelope structure for both the stars. We achieve this using a combination of Self Consistant Field (SCF) technique and composite polytropes, also known as bipolytropes. So far we have been able to generate close binaries with various mass ratios. Another consequence of using bipolytropes is that according to theoretical calculations, the radius of a star should expand when the core mass fraction exceeds a critical value, resulting in interesting consequences in a binary system. We present some initial results of these simulations.

  2. Discs in misaligned binary systems

    NASA Astrophysics Data System (ADS)

    Rawiraswattana, Krisada; Hubber, David A.; Goodwin, Simon P.

    2016-08-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-alignment processes, which tend to misalign the components. The alignment process dominates in systems with misalignment angle near 90°, while the anti-alignment process dominates in systems with the misalignment angle near 0° or 180°. This means that highly misaligned systems will become more aligned but slightly misaligned systems will become more misaligned.

  3. Generating Constant Weight Binary Codes

    ERIC Educational Resources Information Center

    Knight, D.G.

    2008-01-01

    The determination of bounds for A(n, d, w), the maximum possible number of binary vectors of length n, weight w, and pairwise Hamming distance no less than d, is a classic problem in coding theory. Such sets of vectors have many applications. A description is given of how the problem can be used in a first-year undergraduate computational…

  4. Chemical Evolution of Binary Stars

    NASA Astrophysics Data System (ADS)

    Izzard, R. G.

    2013-02-01

    Energy generation by nuclear fusion is the fundamental process that prevents stars from collapsing under their own gravity. Fusion in the core of a star converts hydrogen to heavier elements from helium to uranium. The signature of this nucleosynthesis is often visible in a single star only for a very short time, for example while the star is a red giant or, in massive stars, when it explodes. Contrarily, in a binary system nuclear-processed matter can captured by a secondary star which remains chemically polluted long after its more massive companion star has evolved and died. By probing old, low-mass stars we gain vital insight into the complex nucleosynthesis that occurred when our Galaxy was much younger than it is today. Stellar evolution itself is also affected by the presence of a companion star. Thermonuclear novae and type Ia supernovae result from mass transfer in binary stars, but big questions still surround the nature of their progenitors. Stars may even merge and one of the challenges for the future of stellar astrophysics is to quantitatively understand what happens in such extreme systems. Binary stars offer unique insights into stellar, galactic and extragalactic astrophysics through their plethora of exciting phenomena. Understanding the chemical evolution of binary stars is thus of high priority in modern astrophysics.

  5. Orbits of Six Binary Stars

    NASA Astrophysics Data System (ADS)

    Olevic, D.; Cvetkovic, Z.

    2005-04-01

    Preliminary orbital elements of binary systems WDS 03494-1956 = RST 2324, WDS 03513+2621 = A 1830, WDS 04093-2025 = RST 2333, WDS 06485-1226 = A 2935, WDS 07013-0906 = A 671, and WDS 18323-1439 = CHR 73 are presented. For all systems but WDS 18323-1439 the individual masses and dynamical parallaxes are derived.

  6. A Galactic Binary Detection Pipeline

    NASA Technical Reports Server (NTRS)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  7. A general catalogue of close binary systems

    NASA Technical Reports Server (NTRS)

    Webbink, Ronald F.

    1994-01-01

    A comprehensive catalog of close binary stars to be used for the study of the fundamental properties of stars and for the exploration and elucidation of evolutionary processes in those systems, is presented. Spectroscopic binaries, variable stars, suspected variable stars, and interacting binaries are included in the scope of the catalog.

  8. Observing Massive Black Hole Binary Coalescences with LISA

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2005-01-01

    Massive black hole binary coalescences are among the most important astrophysical sources of gravitational waves to be observed by LISA. The ability to observe and characterize such sources with masses approximately equal to 105 M/odot and larger at high redshifts is strongly dependent on the sensitivity of LISA in the low frequency (0.1 mHz and below) regime. We examine LISA's ability to observe these systems at redshifts up to z approximately equal to 10 for various proposed values of the low frequency sensitivity, under current assumptions about the merger rates. The discussion will focus on the astrophysical information that can be gained by these observations.

  9. Gravity darkening in binary stars

    NASA Astrophysics Data System (ADS)

    Espinosa Lara, F.; Rieutord, M.

    2012-11-01

    Context. Interpretation of light curves of many types of binary stars requires the inclusion of the (cor)relation between surface brightness and local effective gravity. Until recently, this correlation has always been modeled by a power law relating the flux or the effective temperature and the effective gravity, namely Teff ∝ geffβ . Aims: We look for a simple model that can describe the variations of the flux at the surface of stars belonging to a binary system. Methods: This model assumes that the energy flux is a divergence-free vector anti-parallel to the effective gravity. The effective gravity is computed from the Roche model. Results: After explaining in a simple manner the old result of Lucy (1967, Z. Astrophys., 65, 89), which says that β ~ 0.08 for solar type stars, we first argue that one-dimensional models should no longer be used to evaluate gravity darkening laws. We compute the correlation between log Teff and log geff using a new approach that is valid for synchronous, weakly magnetized, weakly irradiated binaries. We show that this correlation is approximately linear, validating the use of a power law relation between effective temperature and effective gravity as a first approximation. We further show that the exponent β of this power law is a slowly varying function, which we tabulate, of the mass ratio of the binary star and the Roche lobe filling factor of the stars of the system. The exponent β remains mostly in the interval [0.20,0.25] if extreme mass ratios are eliminated. Conclusions: For binary stars that are synchronous, weakly magnetized and weakly irradiated, the gravity darkening exponent is well constrained and may be removed from the free parameters of the models.

  10. Sensitivity Analysis Without Assumptions

    PubMed Central

    VanderWeele, Tyler J.

    2016-01-01

    Unmeasured confounding may undermine the validity of causal inference with observational studies. Sensitivity analysis provides an attractive way to partially circumvent this issue by assessing the potential influence of unmeasured confounding on causal conclusions. However, previous sensitivity analysis approaches often make strong and untestable assumptions such as having an unmeasured confounder that is binary, or having no interaction between the effects of the exposure and the confounder on the outcome, or having only one unmeasured confounder. Without imposing any assumptions on the unmeasured confounder or confounders, we derive a bounding factor and a sharp inequality such that the sensitivity analysis parameters must satisfy the inequality if an unmeasured confounder is to explain away the observed effect estimate or reduce it to a particular level. Our approach is easy to implement and involves only two sensitivity parameters. Surprisingly, our bounding factor, which makes no simplifying assumptions, is no more conservative than a number of previous sensitivity analysis techniques that do make assumptions. Our new bounding factor implies not only the traditional Cornfield conditions that both the relative risk of the exposure on the confounder and that of the confounder on the outcome must satisfy but also a high threshold that the maximum of these relative risks must satisfy. Furthermore, this new bounding factor can be viewed as a measure of the strength of confounding between the exposure and the outcome induced by a confounder. PMID:26841057

  11. MILLIONS OF MULTIPLES: DETECTING AND CHARACTERIZING CLOSE-SEPARATION BINARY SYSTEMS IN SYNOPTIC SKY SURVEYS

    SciTech Connect

    Terziev, Emil; Law, Nicholas M.; Arcavi, Iair; Baranec, Christoph; Bui, Khanh; Dekany, Richard G.; Kulkarni, S. R.; Riddle, Reed; Tendulkar, Shriharsh P.; Bloom, Joshua S.; Burse, Mahesh P.; Chorida, Pravin; Das, H. K.; Punnadi, Sujit; Ramaprakash, A. N.; Kraus, Adam L.; Nugent, Peter; Ofek, Eran O.; Sullivan, Mark

    2013-06-01

    The direct detection of binary systems in wide-field surveys is limited by the size of the stars' point-spread functions (PSFs). A search for elongated objects can find closer companions, but is limited by the precision to which the PSF shape can be calibrated for individual stars. Based on a technique from weak-lensing analysis, we have developed the BinaryFinder algorithm to search for close binaries by using precision measurements of PSF ellipticity across wide-field survey images. We show that the algorithm is capable of reliably detecting binary systems down to Almost-Equal-To 1/5 of the seeing limit, and can directly measure the systems' position angles, separations, and contrast ratios. To verify the algorithm's performance we evaluated 100,000 objects in Palomar Transient Factory (PTF) wide-field-survey data for signs of binarity, and then used the Robo-AO robotic laser adaptive optics system to verify the parameters of 44 high-confidence targets. We show that BinaryFinder correctly predicts the presence of close companions with a <11% false-positive rate, measures the detected binaries' position angles within 1 Degree-Sign to 4 Degree-Sign (depending on signal-to-noise ratio and separation), and separations within 25%, and weakly constrains their contrast ratios. When applied to the full PTF data set, we estimate that BinaryFinder will discover and characterize {approx}450,000 physically associated binary systems with separations <2 arcsec and magnitudes brighter than m{sub R} = 18. New wide-field synoptic surveys with high sensitivity and sub-arcsecond angular resolution, such as LSST, will allow BinaryFinder to reliably detect millions of very faint binary systems with separations as small as 0.1 arcsec.

  12. Binary black hole mergers from globular clusters: Masses, merger rates, and the impact of stellar evolution

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carl L.; Chatterjee, Sourav; Rasio, Frederic A.

    2016-04-01

    in the local Universe will have originated in a globular cluster, but we also explore the sensitivity of this result to different assumptions for binary stellar evolution. If black holes were born with significant natal kicks, comparable to those of neutron stars, then the merger rate of binary black holes from globular clusters would be comparable to that from the field, with approximately 1 /2 of mergers originating in clusters. Finally we point out that population synthesis results for the field may also be modified by dynamical interactions of binaries taking place in dense star clusters which, unlike globular clusters, dissolved before the present day.

  13. X-ray binaries in globular clusters

    NASA Technical Reports Server (NTRS)

    Grindlay, Jonathan E.

    1988-01-01

    X-ray and optical studies of compact binaries and globular clusters are reviewed. Topics covered include, the formation of compact binaries by three-body interactions and by tidal capture, studies of the 11 minute binary in NGC 6624 and the 8.5 hour binary in M 15 (AC211), and an evolutionary model for compact binary formation. Optical searches for X-ray binaries in globular clusters are examined including CCD surveys and studies of NGC 6712. In addition, globular clusters with central cusps in their surface brightness profiles, questions concerning the blue color of binaries, diffuse line emission from CVs, and the possibility that X-ray burst sources in the galactic bulge were formed by tidal capture in globular clusters which have since been disrupted are discussed.

  14. Longterm lightcurves of X-ray binaries

    NASA Astrophysics Data System (ADS)

    Clarkson, William

    The X-ray Binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight ( P orb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena, indeed the resulting accretion/ outflow process is among the most efficient energy-conversion machines in the universe. The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves above 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ~3 years' overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X- 1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band. Chapters 1 & 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 & 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE

  15. Binary 193nm photomasks aging phenomenon study

    NASA Astrophysics Data System (ADS)

    Dufaye, Félix; Sartelli, Luca; Pogliani, Carlo; Gough, Stuart; Sundermann, Frank; Miyashita, Hiroyuki; Hidenori, Yoshioka; Charras, Nathalie; Brochard, Christophe; Thivolle, Nicolas

    2011-05-01

    193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long period. These 193nm binary masks seem to be well-known but recent studies have shown surprising degrading effects, like Electric Field induced chromium Migration (EFM) [1] or chromium migration [2] [3] . Phase shift Masks (PSM) or Opaque MoSi On Glass (OMOG) might not be concerned by these effects [4] [6] under certain conditions. In this paper, we will focus our study on two layers gate and metal lines. We will detail the effects of mask aging, with SEM top view pictures revealing a degraded chromium edge profile and TEM chemical analyses demonstrating the growth of a chromium oxide on the sidewall. SEMCD measurements after volume production indicated a modified CD with respect to initial CD data after manufacture. A regression analysis of these CD measurements shows a radial effect, a die effect and an isolated-dense effect. Mask cleaning effectiveness has also been investigated, with sulphate or ozone cleans, to recover the mask quality in terms of CD. In complement, wafer intrafield CD measurements have been performed on the most sensitive structure to monitor the evolution of the aging effect on mask CD uniformity. Mask CD drift have been correlated with exposure dose drift and isolated-dense bias CD drift on wafers. In the end, we will try to propose a physical explanation of this aging phenomenon and a solution to prevent from it occurring.

  16. The MACHO Project LMC variable star inventory. V. Classification and orbits of 611 eclipsing binary stars

    SciTech Connect

    The MACHO Collaboration

    1997-07-01

    We report the characteristics of 611 eclipsing binary stars in the Large Megallanic Cloud found by using the MACHO Project photometry database. The sample is magnitude limited, and extends down the main sequence to about spectral type A0. Many evolved binaries are also included. Each eclipsing binary is classified according to the traditional scheme of the {ital General Catalogue of Variable Stars} (EA and EB), and also according to a new decimal classification scheme defined in this paper. The new scheme is sensitive to the two major sources of variance in eclipsing binary star light curves{emdash}the sum of radii, and the surface-brightness ratio, and allow greater precision in characterizing the light curves. Examples of each type of light curve and their variations are given. Sixty-four of the eclipsing binaries have eccentric, rather than circular, orbits. The ephemeris and principal photometric characteristics of each eclipsing binary are listed in a table. Photometric orbits based on the Nelson{endash}Davis{endash}Etzel model have been fitted to all light curves. These data will be useful for planning future observations of these binaries. Plots of all data and fitted orbits and a table of the fitted orbital parameters are available on the AAS CD-ROM series, Vol. 9, 1997. These data are also available at the MACHO home page (http://wwwmacho.mcmaster.ca/). {copyright} {ital 1997 American Astronomical Society.}

  17. Dynamical Formation Signatures of Black Hole Binaries in the First Detected Mergers by LIGO

    NASA Astrophysics Data System (ADS)

    O’Leary, Ryan M.; Meiron, Yohai; Kocsis, Bence

    2016-06-01

    The dynamical formation of stellar-mass black hole–black hole binaries has long been a promising source of gravitational waves for the Laser Interferometer Gravitational-Wave Observatory (LIGO). Mass segregation, gravitational focusing, and multibody dynamical interactions naturally increase the interaction rate between the most massive black holes in dense stellar systems, eventually leading them to merge. We find that dynamical interactions, particularly three-body binary formation, enhance the merger rate of black hole binaries with total mass M tot roughly as \\propto {M}{{tot}}β , with β ≳ 4. We find that this relation holds mostly independently of the initial mass function, but the exact value depends on the degree of mass segregation. The detection rate of such massive black hole binaries is only further enhanced by LIGO’s greater sensitivity to massive black hole binaries with M tot ≲ 80 {M}ȯ . We find that for power-law BH mass functions dN/dM ∝ M ‑α with α ≤ 2, LIGO is most likely to detect black hole binaries with a mass twice that of the maximum initial black hole mass and a mass ratio near one. Repeated mergers of black holes inside the cluster result in about ∼5% of mergers being observed between two and three times the maximum initial black hole mass. Using these relations, one may be able to invert the observed distribution to the initial mass function with multiple detections of merging black hole binaries.

  18. Binary Candidates and Fractions in the Jovian Trojan and Hilda Populations from NEOWISE Lightcurves

    NASA Astrophysics Data System (ADS)

    Sonnett, Sarah M.; Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J. M.

    2014-11-01

    Objects in orbital resonance with Jupiter, particularly Jovian Trojans (hereafter, Trojans) and Hildas, are some of the most diagnostic and accessible small body populations for constraining planetary migration patterns since their capture and physical state must be explained by dynamical evolution models. Different solar system formation models (e.g., gentle vs. rapid giant planet migration) predict different formation locations and dynamical histories for Trojans (and Hildas, which are likely fed from the Trojan region). Different dynamical environments can also produce different binary fractions as a function of separation between the two components. In order to explore whether the dynamical environment during early solar system evolution was mild or turbulent by helping discern which binary formation mechanism dominated for Trojans and Hildas, we searched the Trojan and Hilda thermal rotational lightcurves cataloged by NEOWISE for anomalously large lightcurve amplitudes indicative of close or contact binaries. These tight binary candidates are in need of dense follow-up observations to confirm their binarity. We also compared binary fractions between various Trojan subpopulations and for Trojans versus Hildas. We present binary fractions corrected for sampling and sensitivity biases and for survey efficiency at detecting tight binaries.

  19. Close supermassive binary black holes

    NASA Astrophysics Data System (ADS)

    Gaskell, C. Martin

    2010-01-01

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive blackhole binary (SMB). The AGN J1536+0441 (=SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that 1536+044 is an example of line emission from a disc. If this is correct, the lack of clear optical spectral evidence for close SMBs is significant and argues either that the merging of close SMBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  20. Binary nucleation at low temperatures

    NASA Technical Reports Server (NTRS)

    Zahoransky, R. A.; Peters, F.

    1985-01-01

    The onset of homogeneous condensation of binary vapors in the supersaturated state is studied in ethanol/n-propanol and water/ethanol via their unsteady expansion in a shock tube at temperatures below 273 K. Ethanol/n-propanol forms a nearly ideal solution, whereas water/ethanol is an example of a strongly nonideal mixture. Vapor mixtures of various compositions are diluted in dry air at small mole fractions and expanded in the driver section from room temperature. The onset of homogeneous condensation is detected optically and the corresponding thermodynamic state is evaluated. The experimental results are compared with the binary nucleation theory, and the particular problems of theoretical evaluation at low temperatures are discussed.

  1. Binary Stars in SBS Survey

    NASA Astrophysics Data System (ADS)

    Erastova, L. K.

    2016-06-01

    Thirty spectroscopic binary stars were found in the Second Byurakan Survey (SBS). They show composite spectra - WD(DA)+dM or dC (for example Liebert et al. 1994). They may have red color, if the radiation of the red star dominates, and blue one, if the blue star is brighter and have peculiar spectrum in our survey plate. We obtained slit spectra for most of such objects. But we often see the spectrum of one component, because our slit spectra did not cover all optical range. We examine by eye the slit spectra of all SBS stellar objects (˜700) in SDSS DR7, DR8 or DR9 independent on our observations. We confirmed or discovered the duplicity of 30 stars. Usually they are spectroscopic binaries, where one component is WD (DA) and the second one is a red star with or without emission. There also are other components combinations. Sometimes there are emission lines, probably, indicating variable ones.

  2. Orbits of six visual binaries

    NASA Astrophysics Data System (ADS)

    Couteau, P.

    1987-12-01

    Recent interferometric and visual observations have been used to compile orbital elements for the binaries COU 79, Phi 342, ADS 5726, COU 292, ADS 15487, and COU 542. The problematic binaries COU 79 and Phi 342 are discussed in detail. The results for COU 79 indicate a dynamic parallax of 0.0182 arcsec and absolute visual magnitudes of 2.5 and 2.8, values which are not consistent with the previously-determined spectral type of F6V. A parallax of 0.01420 arcsec is found for Phi 342, and the visual magnitudes of 2.74 and 3.13 are indicative of superluminous stars outside of the main sequence.

  3. CHARACTERIZATION OF SEVEN ULTRA-WIDE TRANS-NEPTUNIAN BINARIES

    SciTech Connect

    Parker, Alex H.; Kavelaars, J. J.; Petit, Jean-Marc; Jones, Lynne; Gladman, Brett; Parker, Joel

    2011-12-10

    The low-inclination component of the Classical Kuiper Belt is host to a population of extremely widely separated binaries. These systems are similar to other trans-Neptunian binaries (TNBs) in that the primary and secondary components of each system are of roughly equal size. We have performed an astrometric monitoring campaign of a sample of seven wide-separation, long-period TNBs and present the first-ever well-characterized mutual orbits for each system. The sample contains the most eccentric (2006 CH{sub 69}, e{sub m} = 0.9) and the most widely separated, weakly bound (2001 QW{sub 322}, a/R{sub H} {approx_equal} 0.22) binary minor planets known, and also contains the system with lowest-measured mass of any TNB (2000 CF{sub 105}, M{sub sys} {approx_equal} 1.85 Multiplication-Sign 10{sup 17} kg). Four systems orbit in a prograde sense, and three in a retrograde sense. They have a different mutual inclination distribution compared to all other TNBs, preferring low mutual-inclination orbits. These systems have geometric r-band albedos in the range of 0.09-0.3, consistent with radiometric albedo estimates for larger solitary low-inclination Classical Kuiper Belt objects, and we limit the plausible distribution of albedos in this region of the Kuiper Belt. We find that gravitational collapse binary formation models produce an orbital distribution similar to that currently observed, which along with a confluence of other factors supports formation of the cold Classical Kuiper Belt in situ through relatively rapid gravitational collapse rather than slow hierarchical accretion. We show that these binary systems are sensitive to disruption via collisions, and their existence suggests that the size distribution of TNOs at small sizes remains relatively shallow.

  4. Characterization of Seven Ultra-wide Trans-Neptunian Binaries

    NASA Astrophysics Data System (ADS)

    Parker, Alex H.; Kavelaars, J. J.; Petit, Jean-Marc; Jones, Lynne; Gladman, Brett; Parker, Joel

    2011-12-01

    The low-inclination component of the Classical Kuiper Belt is host to a population of extremely widely separated binaries. These systems are similar to other trans-Neptunian binaries (TNBs) in that the primary and secondary components of each system are of roughly equal size. We have performed an astrometric monitoring campaign of a sample of seven wide-separation, long-period TNBs and present the first-ever well-characterized mutual orbits for each system. The sample contains the most eccentric (2006 CH69, em = 0.9) and the most widely separated, weakly bound (2001 QW322, a/RH ~= 0.22) binary minor planets known, and also contains the system with lowest-measured mass of any TNB (2000 CF105, M sys ~= 1.85 × 1017 kg). Four systems orbit in a prograde sense, and three in a retrograde sense. They have a different mutual inclination distribution compared to all other TNBs, preferring low mutual-inclination orbits. These systems have geometric r-band albedos in the range of 0.09-0.3, consistent with radiometric albedo estimates for larger solitary low-inclination Classical Kuiper Belt objects, and we limit the plausible distribution of albedos in this region of the Kuiper Belt. We find that gravitational collapse binary formation models produce an orbital distribution similar to that currently observed, which along with a confluence of other factors supports formation of the cold Classical Kuiper Belt in situ through relatively rapid gravitational collapse rather than slow hierarchical accretion. We show that these binary systems are sensitive to disruption via collisions, and their existence suggests that the size distribution of TNOs at small sizes remains relatively shallow.

  5. Circularization time of binary galaxies

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; de Freitas Pacheco, J. A.

    1994-11-01

    We report the results of numerical experiments performed to study the orbital circularization time of binary galaxies. We find that the time scale is quite long (larger than the Hubble time), confirming earlier calculations. The results depend on the initial conditions. From our simulations we obtained a fitting formula for the circularization time as a function of the initial orbital parameters like the pericentric distance, mass ratio, and eccentricity.

  6. Cool Star Binaries with ALEXIS

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1998-01-01

    We proposed to search for high-temperature, flare-produced Fe XXIII line emission from active cool star binary systems using the ALEXIS all-sky survey. Previous X-ray transient searches with ARIEL V and HEAO-1, and subsequent shorter duration monitoring with the GINGA and EXOSAT satellites demonstrated that active binaries can produce large (EM approximately equals 10(exp 55-56/cu cm) X-ray flares lasting several hours or longer. Hot plasma from these flares at temperatures of 10(exp 7)K or more should produce Fe XXIII line emission at lambda = 132.8 A, very near the peak response of ALEXIS telescopes 1A and 2A. Our primary goals were to estimate flare frequency for the largest flares in the active binary systems, and, if the data permitted, to derive a distribution of flare energy vs. frequency for the sample as a whole. After a long delay due to the initial problems with the ALEXIS attitude control, the heroic efforts on the part of the ALEXIS satellite team enabled us to carry out this survey. However, the combination of the higher than expected and variable background in the ALEXIS detectors, and the lower throughput of the ALEXIS telescopes resulted in no convincing detections of large flares from the active binary systems. In addition, vignetting-corrected effective exposure times from the ALEXIS aspect solution were not available prior to the end of this contract; therefore, we were unable to convert upper limits measured in ALEXIS counts to the equivalent L(sub EUV).

  7. Looking for Interacting Binaries in Old Open Clusters

    NASA Technical Reports Server (NTRS)

    Grindley, Jonathan

    2005-01-01

    We requested a 12 ks observation of the old open cluster NGC7142 with the aim to investigate the population of interacting binaries, and compare the properties with those of interacting binaries in other old open clusters. Unfortunately, the observation suffered from long periods of background flaring, and as a result the effective exposure time was shortened to only approximately 25% of the planned exposure. The sensitivity to detect sources in the cluster was therefore much reduced, hampering a useful comparison with other clusters observed with Chandra and XMM. We detect 5 sources (all less than 300 counts) in the full field of view of the detectors; based on the large separations from the cluster center, we expect that at least 3-4 are not associated with the cluster. A brief paper that reports the results is in preparation.

  8. Very faint X-ray binaries with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Armas Padilla, M.

    2016-06-01

    A population of very faint X-ray binaries has been discovered in the last years thanks to the improvement in sensitivity and resolution of the new generations of X-ray missions. These systems show anomalously low luminosities, below 10^{36} ergs/sec, challenging our understanding of accretion physics and binary evolution models, and thereby opening new windows for both observational and theoretical work on accretion onto compact objects. XMM-Newton is playing a crucial role in the study of this dim family of objects thanks to its incomparable spectral capabilities at low luminosities. I will review the state-of-the-art of the field and present our XMM results in both black hole and neutron star objects. Finally, I will discuss the possibilities that the new generation of X-ray telescopes offer for this research line.

  9. Impact of LISA's Low Frequency Sensitivity on Observations of Massive Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Baker, J.; Centrella, J.

    2005-01-01

    LISA will be able to detect gravitational waves from inspiralling massive black hole (MBH) binaries out to redshifts z > 10. If the binary masses and luminosity distances can be extracted from the Laser Interferometer Space Antenna (LISA) data stream, this information can be used to reveal the merger history of MBH binaries and their host galaxies in the evolving universe. Since this parameter extraction generally requires that LISA observe the inspiral for a significant fraction of its yearly orbit, carrying out this program requires adequate sensitivity at low frequencies, f < 10(exp -4) Hz. Using several candidate low frequency sensitivities, we examine LISA's potential for characterizing MBH binary coalescences at redshifts z > 1.

  10. Pulsed Accretion onto Eccentric and Circular Binaries

    NASA Astrophysics Data System (ADS)

    Muñoz, Diego J.; Lai, Dong

    2016-08-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ∼ 5 times the binary period P b, accretion onto an eccentric binary is predominantly modulated at the period ∼ 1{P}{{b}}. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10–20 times larger than its companion. This “symmetry breaking” between the stars, however, alternates over timescales of order 200P b and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the net accretion rates onto individual stars are the same, reaching a quasi-steady state with the circumbinary disk. These results have important implications for the accretion behavior of binary T Tauri stars and supermassive binary black holes.

  11. Pulsed Accretion onto Eccentric and Circular Binaries

    NASA Astrophysics Data System (ADS)

    Muñoz, Diego J.; Lai, Dong

    2016-08-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ˜ 5 times the binary period P b, accretion onto an eccentric binary is predominantly modulated at the period ˜ 1{P}{{b}}. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10–20 times larger than its companion. This “symmetry breaking” between the stars, however, alternates over timescales of order 200P b and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the net accretion rates onto individual stars are the same, reaching a quasi-steady state with the circumbinary disk. These results have important implications for the accretion behavior of binary T Tauri stars and supermassive binary black holes.

  12. Galaxy Rotation and Rapid Supermassive Binary Coalescence

    NASA Astrophysics Data System (ADS)

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-01

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

  13. Young and Waltzing Binary Stars

    NASA Astrophysics Data System (ADS)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  14. Evolution of binary stars in multiple-population globular clusters - II. Compact binaries

    NASA Astrophysics Data System (ADS)

    Hong, Jongsuk; Vesperini, Enrico; Sollima, Antonio; McMillan, Stephen L. W.; D'Antona, Franca; D'Ercole, Annibale

    2016-04-01

    We present the results of a survey of N-body simulations aimed at exploring the evolution of compact binaries in multiple-population globular clusters. We show that as a consequence of the initial differences in the structural properties of the first-generation (FG) and the second-generation (SG) populations and the effects of dynamical processes on binary stars, the SG binary fraction decreases more rapidly than that of the FG population. The difference between the FG and SG binary fraction is qualitatively similar to but quantitatively smaller than that found for wider binaries in our previous investigations. The evolution of the radial variation of the binary fraction is driven by the interplay between binary segregation, ionization and ejection. Ionization and ejection counteract in part the effects of mass segregation but for compact binaries the effects of segregation dominate and the inner binary fraction increases during the cluster evolution. We explore the variation of the difference between the FG and the SG binary fraction with the distance from the cluster centre and its dependence on the binary binding energy and cluster structural parameters. The difference between the binary fraction in the FG and the SG populations found in our simulations is consistent with the results of observational studies finding a smaller binary fraction in the SG population.

  15. Extrasolar binary planets. I. Formation by tidal capture during planet-planet scattering

    SciTech Connect

    Ochiai, H.; Nagasawa, M.; Ida, S.

    2014-08-01

    We have investigated (1) the formation of gravitationally bounded pairs of gas-giant planets (which we call 'binary planets') from capturing each other through planet-planet dynamical tide during their close encounters and (2) the subsequent long-term orbital evolution due to planet-planet and planet-star quasi-static tides. For the initial evolution in phase 1, we carried out N-body simulations of the systems consisting of three Jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing, and this fraction is almost independent of the initial stellarcentric semimajor axes of the planets, while ejection and merging rates sensitively depend on the semimajor axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by long-term quasi-static tide. We analytically calculated the quasi-static tidal evolution in phase 2. The binary planets first enter the spin-orbit synchronous state by the planet-planet tide. The planet-star tide removes angular momentum of the binary motion, eventually resulting in a collision between the planets. However, we found that the binary planets survive the tidal decay for the main-sequence lifetime of solar-type stars (∼10 Gyr), if the binary planets are beyond ∼0.3 AU from the central stars. These results suggest that the binary planets can be detected by transit observations at ≳ 0.3 AU.

  16. STRUCTURE AND EVOLUTION OF CIRCUMBINARY DISKS AROUND SUPERMASSIVE BLACK HOLE BINARIES

    SciTech Connect

    Rafikov, Roman R.

    2013-09-10

    We explore properties of circumbinary disks around supermassive black hole (SMBH) binaries in centers of galaxies by reformulating standard viscous disk evolution in terms of the viscous angular momentum flux F{sub J}. If the binary stops gas inflow and opens a cavity in the disk, then the inner disk evolves toward a constant-F{sub J} (rather than a constant M-dot ) state. We compute disk properties in different physical regimes relevant for SMBH binaries, focusing on the gas-assisted evolution of systems starting at separations 10{sup -4} - 10{sup -2} pc, and find the following. (1) Mass pileup at the inner disk edge caused by the tidal barrier accelerates binary inspiral. (2) Binaries can be forced to merge even by a disk with a mass below that of the secondary. (3) Torque on the binary is set non-locally, at radii far larger than the binary semi-major axis; its magnitude does not reflect disk properties in the vicinity of the binary. (4) Binary inspiral exhibits hysteresis-it depends on the past evolution of the disk. (5) The Eddington limit can be important for circumbinary disks even if they accrete at sub-Eddington rates, but only at late stages of the inspiral. (6) Gas overflow across the orbit of the secondary can be important for low secondary mass, high- M-dot systems, but mainly during the inspiral phase dominated by the gravitational wave emission. (7) Circumbinary disks emit more power and have harder spectra than constant M-dot disks; their spectra are very sensitive to the amount of overflow across the secondary orbit.

  17. Hunting for brown dwarf binaries and testing atmospheric models with X-Shooter

    NASA Astrophysics Data System (ADS)

    Manjavacas, E.; Goldman, B.; Alcalá, J. M.; Zapatero-Osorio, M. R.; Béjar, V. J. S.; Homeier, D.; Bonnefoy, M.; Smart, R. L.; Henning, T.; Allard, F.

    2016-01-01

    The determination of the brown dwarf binary fraction may contribute to the understanding of the substellar formation mechanisms. Unresolved brown dwarf binaries may be revealed through their peculiar spectra or the discrepancy between optical and near-infrared spectral-type classification. We obtained medium-resolution spectra of 22 brown dwarfs with these characteristics using the X-Shooter spectrograph at the Very Large Telescope. We aimed to identify brown dwarf binary candidates, and to test if the BT-Settl 2014 atmospheric models reproduce their observed spectra. To find binaries spanning the L-T boundary, we used spectral indices and compared the spectra of the selected candidates to single spectra and synthetic binary spectra. We used synthetic binary spectra with components of same spectral type to determine as well the sensitivity of the method to this class of binaries. We identified three candidates to be combination of L plus T brown dwarfs. We are not able to identify binaries with components of similar spectral type. In our sample, we measured minimum binary fraction of 9.1^{+9.9}_{-3.0} per cent. From the best fit of the BT-Settl models 2014 to the observed spectra, we derived the atmospheric parameters for the single objects. The BT-Settl models were able to reproduce the majority of the spectral energy distributions from our objects, and the variation of the equivalent width of the Rb I (794.8 nm) and Cs I (852.0 nm) lines with the spectral type. None the less, these models did not reproduce the evolution of the equivalent widths of the Na I (818.3 and 819.5 nm) and K I (1253 nm) lines with the spectral type.

  18. Massive Binaries: Dynamical and Evolutionary Transformations

    NASA Astrophysics Data System (ADS)

    Gies, D. R.

    2012-12-01

    Observations of massive binaries offer us key insight about the formation, evolution, and destinies of massive stars. Here I review some advances in observational and theoretical studies of massive binaries. Surveys for binaries using radial velocity, photometric, and high angular resolution methods show that the binary frequency is high for O stars in clusters. Evolutionary models for interacting binaries demonstrate the importance of angular momentum transfer during Roche lobe overflow. The mass gainer may reach critical rotation and stem further accretion, and there are many observed cases that show the consequences of such mass loss and transfer. New hydrodynamical models describe colliding wind physics in eccentric binaries such as η Carinae and WR 140. All these research topics are championed by Tony Moffat, and the current richness of this field is due in large measure to his energetic pursuits.

  19. New RR Lyrae variables in binary systems

    NASA Astrophysics Data System (ADS)

    Hajdu, G.; Catelan, M.; Jurcsik, J.; Dékány, I.; Drake, A. J.; Marquette, J.-B.

    2015-04-01

    Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated (O-C) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 yr, leading to a final sample of 12 firm binary candidates. We provide O-C diagrams and binary parameters for this final sample, and also discuss the properties of eight additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that ≳ 4 per cent of the RRL reside in binary systems.

  20. Polyamine-capped gold nanorod as a localized surface Plasmon resonance probe for rapid and sensitive copper(II) ion detection.

    PubMed

    Liu, Yingshuai; Zhao, Yanan; Wang, Yuchen; Li, Chang Ming

    2015-02-01

    Polyamine-capped gold nanorods (AuNRs) were developed as nanoprobes for localized surface Plasmon resonance (LSPR)-based simple, selective, and sensitive detection of Cu(2+) ions. Poly(sodium-4-styrenesulfonate) (PSS) and polyethylenimine (PEI) was successively adsorbed on the positively charged AuNRs via electrostatic adsorption, resulting in polyamine-capped AuNRs (called "PEI-PSS-AuNRs" thereafter), in which PEI offered bifunctions of providing sufficient positive charges and static hindrance to ensure stability of the AuNRs and serving as a Cu(2+) ion recognition molecule via specific chelation. The as-prepared PEI-PSS-AuNRs were characterized by UV-vis spectroscopy, zeta potential analyzer, and transmission electron microscopy (TEM). Experimental results show that the polyelectrolytes PSS and PEI have been successfully adsorbed on AuNRs. The PEI-PSS-AuNRs were then employed as nanoprobes for Cu(2+) ion detection. A linear range from 1μM to 5mM and a detection limit (3σ/k) of 0.24μM were achieved in PBS. The concentration dependent shifts of longitudinal extinction peak of PEI-PSS-AuNRs notably results from the specific PEI-Cu(2+) chelation-induced changes of dielectric property of polyelectrolyte film attached on nanoprobes. The negligible interference from other metal ions demonstrates good selectivity of the PEI-PSS-AuNRs for Cu(2+) sensing. Moreover, the developed probes were successfully used to detect Cu(2+) in river water, demonstrating their feasibility for analysis of surface water sample. PMID:25463169

  1. Close binary stars in globular clusters

    NASA Technical Reports Server (NTRS)

    Margon, Bruce

    1991-01-01

    Although close binary stars are thought theoretically to play a major role in globular cluster dynamics, virtually no non-degenerate close binaries are known in clusters. We review the status of observations in this area, and report on two new programs which are finally yielding candidate systems suitable for further study. One of the objects, a close eclipsing system in omega Cen, is also a big straggler, thus finally proving firm evidence that globular cluster blue stragglers really are binary stars.

  2. Survival of planets around shrinking stellar binaries

    NASA Astrophysics Data System (ADS)

    Munoz, Diego Jose; Lai, Dong

    2015-12-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 days, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. We present new results (PNAS 112, 30, p 9264) on the orbital evolution of planets around binaries undergoing orbital decay by this "LK+tide" mechanism. From secular and N-body calculations, we show how planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Either outcome can explain these planets' elusiveness to detection. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer specific predictions as to what their orbital configurations should be like.

  3. Survival of planets around shrinking stellar binaries

    PubMed Central

    Muñoz, Diego J.; Lai, Dong

    2015-01-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov–Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like. PMID:26159412

  4. Survival of planets around shrinking stellar binaries.

    PubMed

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like. PMID:26159412

  5. Nonergodicity of microfine binary systems

    NASA Astrophysics Data System (ADS)

    Son, L. D.; Sidorov, V. E.; Popel', P. S.; Shul'gin, D. B.

    2016-02-01

    The correction to the equation of state that is related to the nonergodicity of diffusion dynamics is discussed for a binary solid solution with a limited solubility. It is asserted that, apart from standard thermodynamic variables (temperature, volume, concentration), this correction should be taken into account in the form of the average local chemical potential fluctuations associated with microheterogeneity in order to plot a phase diagram. It is shown that a low value of this correction lowers the miscibility gap and that this gap splits when this correction increases. This situation is discussed for eutectic systems and Ga-Pb, Fe-Cu, and Cu-Zr alloys.

  6. Tomographic reconstruction of binary fields

    NASA Astrophysics Data System (ADS)

    Roux, Stéphane; Leclerc, Hugo; Hild, François

    2012-09-01

    A novel algorithm is proposed for reconstructing binary images from their projection along a set of different orientations. Based on a nonlinear transformation of the projection data, classical back-projection procedures can be used iteratively to converge to the sought image. A multiscale implementation allows for a faster convergence. The algorithm is tested on images up to 1 Mb definition, and an error free reconstruction is achieved with a very limited number of projection data, saving a factor of about 100 on the number of projections required for classical reconstruction algorithms.

  7. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  8. Coronal Metallicities of Active Binaries

    NASA Astrophysics Data System (ADS)

    Kashyap, V.; Drake, J. J.; Pease, D. O.; Schmitt, J. H. M. M.

    1998-09-01

    We analyze EUV and X-ray data on a sample of X-ray active binary stars to determine coronal abundances. EUVE spectrometer data are used to obtain line fluxes, which are then used to determine Differential Emission Measures (DEMs). The continuum emission predicted for these DEMs (constrained at high temperatures by measurements in the X-ray regime where available) are then compared with EUVE/DS counts to derive coronal metallicities. These measurements indicate whether the coronae on these stars are metal deficient (the ``MAD Syndrome'') or subject to the FIP-effect (low First Ionization Potential elements have enhanced abundances relative to the photospheres).

  9. Young and Waltzing Binary Stars

    NASA Astrophysics Data System (ADS)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  10. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  11. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  12. Graphene oxide quantum dots@silver core-shell nanocrystals as turn-on fluorescent nanoprobe for ultrasensitive detection of prostate specific antigen.

    PubMed

    Pei, Haimeng; Zhu, Shuyun; Yang, Minghui; Kong, Rongmei; Zheng, Yiqun; Qu, Fengli

    2015-12-15

    We report a fluorescent turn-on nanoprobe for ultrasensitive detection of prostate specific antigen (PSA) based on graphene oxide quantum dots@silver (GQDs@Ag) core-shell nanocrystals. The success of this work relies on the assembly of quantities of GQDs in one GQDs@Ag probe, which makes the ratio of probe to target significantly increased and thus enables the fluorescent signal enhancement. When the silver shell was removed via oxidative etching using hydrogen peroxide (H2O2), the incorporated GQDs could be readily released and the whole process caused little change to their fluorescence performance. We tested the probe for the ultrasensitive detection of PSA based on the sandwich protocol of immunosensors. In particular, magnetic beads (MBs) were employed to immobilize anti-PSA antibody (Ab1) and acted as a separable capture probe, while GQDs@Ag was used as detection probe by linking antibody (Ab2). The developed immunosensor showed a good linear relationship between the fluorescence intensity and the concentration of PSA in the range from 1 pg/mL to 20 ng/mL with a detection limit of 0.3 pg/mL. The immunosensor used for the analysis of clinical serum samples exhibited satisfactory results, which demonstrated its potential for practical diagnostic applications. This method provides a possible solution to the application of GQDs in immunosensing and could be potentially extended to other similar systems. PMID:26257182

  13. High-resolution nanoprobe X-ray fluorescence characterization of heterogeneous calcium and heavy metal distributions in alkali-activated fly ash.

    PubMed

    Provis, John L; Rose, Volker; Bernal, Susan A; van Deventer, Jannie S J

    2009-10-01

    The nanoscale distribution of elements within fly ash and the aluminosilicate gel products of its alkaline activation ("fly ash geopolymers") are analyzed by means of synchrotron X-ray fluorescence using a hard X-ray Nanoprobe instrument. The distribution of calcium within a hydroxide-activated (fly ash/KOH solution) geopolymer gel is seen to be highly heterogeneous, with these data providing for the first time direct evidence of the formation of discrete high-calcium particles within the binder structure of a geopolymer synthesized from a low-calcium (<2 wt % as oxides) fly ash. The silicate-activated (fly ash/potassium silicate solution) sample, by contrast, shows a much more homogeneous geopolymer gel binder structure surrounding the unreacted fly ash particles. This has important implications for the understanding of calcium chemistry within aluminosilicate geopolymer gel phases. Additionally, chromium and iron are seen to be very closely correlated within the structures of both fly ash and the geopolymer product and remain within the regions of the geopolymer which can be identified as unreacted fly ash particles. Given that the potential for chromium release has been one of the queries surrounding the widespread utilization of construction materials derived from fly ash, the observation that this element appears to be localized within the fly ash rather than dispersed throughout the gel binder indicates that it is unlikely to be released problematically into the environment. PMID:19788232

  14. High-sensitivity label-free optical fiber optrodes based on the excitation of Bloch surface waves

    NASA Astrophysics Data System (ADS)

    Scaravilli, M.; Castaldi, G.; Cusano, A.; Galdi, V.

    2016-05-01

    In this study, the possibility to excite Bloch surface waves (BSWs) on the tip of a single-mode optical fiber is explored for the first time. In particular, we first show the possibility to achieve an on-tip excitation of BSWs, with optimized characteristic of the arising resonances, via an "all-fiber" grating-coupled configuration. Furthermore, envisioning novel high-performance fiber tip nanoprobes for label-free biosensing, we introduce an ad hoc design aimed at maximizing the refractive-index sensitivity. Numerical results indicate that the estimated sensitivities are comparable with those exhibited by current plasmonic lab-on-tip bio-probes, but are accompanied by a higher spectral selectivity. Therefore, this preliminary work paves the way to the development of new classes of miniaturized surface-wave optical fiber devices for low-detection-limit label-free chemical and biological sensing.

  15. Polarisation modulation in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ingram, Adam; Maccarone, Thomas

    2016-07-01

    X-ray polarimetry promises to provide a powerful new lever arm for studying accretion onto black holes with the next generation of X-ray telescopes. I will discuss how polarisation can be used to help constrain the physical origin of quasi-periodic oscillations (QPOs) observed in the X-ray light curves of accreting black holes. QPOs may be signatures of the frame dragging effect: in General Relativity, a spinning black hole twists up the surrounding space-time, causing vertical precession of nearby orbits. In the truncated disc / precessing inner flow model, the entire inner accretion flow precesses as a solid body causing a modulation in the X-ray flux through solid angle and Doppler effects. This model also predicts the observed polarisation of the X-ray signal to vary quasi-periodically. I will summarise our work to model the polarisation signal from a precessing accretion flow, starting with simple assumptions about the emission mechanism but taking General Relativity fully into account. We find that it should be possible to measure the predicted modulation in polarisation degree for a reasonable region of parameter space with a polarimeter capable of detecting ~60 counts per second from a bright black hole binary. I will also show that sensitivity can be greatly improved by correlating the signal with a high count rate reference band signal.

  16. Phonon Dispersion in Equiatomic Li-Based Binary Alloys

    NASA Astrophysics Data System (ADS)

    Aditya, Vora M.

    2008-02-01

    The computations of the phonon dispersion curves (PDC) of four equiatomic Li-based binary alloys, namely Li0.5Na0.5, Li0.5K0.5, Li0.5Rb0.5 and Li0.5Cs0.5, to second order in the local model potential is discussed in terms of the real-space sum of Born von Karman central force constants. Instead of the concentration average of the force constants of metallic Li, Na, K, Rb and Cs, the pseudo-alloy atom (PAA) is adopted to compute directly the force constants of four equiatomic Li-based binary alloys. The exchange and correlation functions due to Hartree (H) and Ichimaru-Utsumi (IU) are used to investigate the influence of screening effects. The phonon frequencies of four equiatomic Li-based binary alloys in the longitudinal branch are more sensitive to the exchange and correlation effects in comparison with the transverse branches. However, the frequencies in the longitudinal branch are suppressed due to IU-screening function than the frequencies due to static H-screening function.

  17. Searching Planets Around Some Selected Eclipsing Close Binary Stars Systems

    NASA Astrophysics Data System (ADS)

    Nasiroglu, Ilham; Slowikowska, Agnieszka; Krzeszowski, Krzysztof; Zejmo, M. Michal; Er, Hüseyin; Goździewski, Krzysztof; Zola, Stanislaw; Koziel-Wierzbowska, Dorota; Debski, Bartholomew; Ogloza, Waldemar; Drozdz, Marek

    2016-07-01

    We present updated O-C diagrams of selected short period eclipsing binaries observed since 2009 with the T100 Telescope at the TUBITAK National Observatory (Antalya, Turkey), the T60 Telescope at the Adiyaman University Observatory (Adiyaman, Turkey), the 60cm at the Mt. Suhora Observatory of the Pedagogical University (Poland) and the 50cm Cassegrain telescope at the Fort Skala Astronomical Observatory of the Jagiellonian University in Krakow, Poland. All four telescopes are equipped with sensitive, back-illuminated CCD cameras and sets of wide band filters. One of the targets in our sample is a post-common envelope eclipsing binary NSVS 14256825. We collected more than 50 new eclipses for this system that together with the literature data gives more than 120 eclipse timings over the time span of 8.5 years. The obtained O-C diagram shows quasi-periodic variations that can be well explained by the existence of the third body on Jupiter-like orbit. We also present new results indicating a possible light time travel effect inferred from the O-C diagrams of two other binary systems: HU Aqr and V470 Cam.

  18. Observation of asteroids with GRAVITY - Physical characterization of binary systems

    NASA Astrophysics Data System (ADS)

    Matter, A.; Delbo, M.; Carry, B.; Tanga, P.

    2014-12-01

    Density and internal structures are among the most important characteristics of asteroids, yet these properties are also some of the least known. For distant asteroids (in the Main Belt and beyond) these properties were up to now accessible only for the largest (>100 km in size) asteroids. Going to smaller and fainter asteroids can revolutionize our understanding because we will be sampling a new regime in physical properties. Here we discuss how ground-based optical interferometry with the GRAVITY instrument can be used to observe the motion of asteroid satellites to determine the mass of small binary systems. Following the expected sensitivity performances in K-band of GRAVITY, we present a sample of binary targets potentially observable in single-field mode. The feasibility of such observations will strongly be dependent on the ability of the control software of GRAVITY to track objects moving at high rate on the sky (differential motion ˜f 10 mas.s^{-1}). Although the dual-field mode could allow to increase the sample of small binary asteroids observable, it seems to be currently unfeasible given the high differential motion of asteroids.

  19. Mutual Orbits of Transneptunian Binaries

    NASA Astrophysics Data System (ADS)

    Grundy, William M.; Noll, K. S.; Roe, H. G.; Porter, S. B.; Trujillo, C. A.; Benecchi, S. D.; Buie, M. W.

    2012-10-01

    We report the latest results from a program of high spatial resolution imaging to resolve the individual components of binary transneptunian objects. These observations use Hubble Space Telescope and also laser guide star adaptive optics systems on Keck and Gemini telescopes on Mauna Kea. From relative astrometry over multiple epochs, we determine the mutual orbits of the components, and thus the total masses of the systems. Accurate masses anchor subsequent detailed investigations into the physical characteristics of these systems. For instance, dynamical masses enable computation of bulk densities for systems where the component sizes can be estimated from other measurements. Additionally, patterns in the ensemble characteristics of binary orbits offer clues to circumstances in the protoplanetary nebula when these systems formed, as well as carrying imprints of various subsequent dynamical evolution processes. The growing ensemble of known orbits shows intriguing patterns that can shed light on the evolution of this population of distant objects. This work has been supported by an NSF Planetary Astronomy grant and by several Hubble Space Telescope and NASA Keck data analysis grants. The research makes use of data from the Gemini Observatory obtained through NOAO survey program 11A-0017, from a large number of Hubble Space Telescope programs, and from several NASA Keck programs.

  20. 2-D traveling-wave patterns in binary fluid convection

    SciTech Connect

    Surko, C.M.; Porta, A.L.

    1996-12-31

    An overview is presented of recent experiments designed to study two-dimensional traveling-wave convection in binary fluid convection in a large aspect ratio container. Disordered patterns are observed when convection is initiated. As time proceeds, they evolve to more ordered patterns, consisting of several domains of traveling-waves separated by well-defined domain boundaries. The detailed character of the patterns depends sensitively on the Rayleigh number. Numerical techniques are described which were developed to provide a quantitative characterization of the traveling-wave patterns. Applications of complex demodulation techniques are also described, which make a detailed study of the structure and dynamics of the domain boundaries possible.

  1. Binary Colloidal Alloy Test-5: Three-Dimensional Melt

    NASA Technical Reports Server (NTRS)

    Yodh, Arjun G.

    2008-01-01

    Binary Colloidal Alloy Test - 5: Three-Dimensional Melt (BCAT-5-3DMelt) photographs initially randomized colloidal samples in microgravity to determine their resulting structure over time. BCAT-5-3D-Melt will allow the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-3D-Melt will look at the mechanisms of melting using three-dimensional temperature sensitive colloidal crystals. Results will help scientists develop fundamental physics concepts previously shadowed by the effects of gravity.

  2. Detectability of eccentric compact binary coalescences with advanced gravitational-wave detectors

    NASA Astrophysics Data System (ADS)

    Coughlin, M.; Meyers, P.; Thrane, E.; Luo, J.; Christensen, N.

    2015-03-01

    Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. While most binaries are expected to possess circular orbits, some may be eccentric, for example, if they are formed through dynamical capture. Eccentric orbits can create difficulty for matched filtering searches due to the challenges of creating effective template banks to detect these signals. In previous work, we showed how seedless clustering can be used to detect low-mass (Mtotal≤10 M⊙) compact binary coalescences for both spinning and eccentric systems, assuming a circular post-Newtonian expansion. Here, we describe a parametrization that is designed to maximize sensitivity to low-eccentricity (0 ≤ɛ ≤0.6 ) systems, derived from the analytic equations. We show that this parametrization provides a robust and computationally efficient method for detecting eccentric low-mass compact binaries. Based on these results, we conclude that advanced detectors will have a chance of detecting eccentric binaries if optimistic models prove true. However, a null observation is unlikely to firmly rule out models of eccentric binary populations.

  3. Fabricating binary optics: An overview of binary optics process technology

    NASA Technical Reports Server (NTRS)

    Stern, Margaret B.

    1993-01-01

    A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.

  4. Gravitational radiation, inspiraling binaries, and cosmology

    NASA Technical Reports Server (NTRS)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  5. Spectroscopic Binary Frequency among CNO Stars

    NASA Astrophysics Data System (ADS)

    Levato, H.; Malaroda, S.; Garcia, B.; Morell, N.

    1987-05-01

    ABSTRACT. Radial velocity variations are- analyzed through a sample of 35 OB stars with CH anomalies.Bolton and Rogers' proposal (1978) is con- firmed in the sense that the OBN stars appear preferably in short-period binary systems, in contrast to OBC stars. : STARS-BINARY - STARS-EARLY TYPE

  6. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    SciTech Connect

    Iwasawa, Masaki; An, Sangyong; Matsubayashi, Tatsushi; Funato, Yoko; Makino, Junichiro

    2011-04-10

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  7. An Acidity Scale for Binary Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1987-01-01

    Discusses the classification of binary oxides as acidic, basic, or amphoteric. Demonstrates how a numerical scale for acidity/basicity of binary oxides can be constructed using thermochemical data for oxoacid salts. Presents the calculations derived from the data that provide the numeric scale values. (TW)

  8. A MULTIWAVELENGTH STUDY OF BINARY QUASARS AND THEIR ENVIRONMENTS

    SciTech Connect

    Green, Paul J.; Aldcroft, Thomas L.; Trichas, Markos; Myers, Adam D.; Barkhouse, Wayne A.; Richards, Gordon T.; Ruiz, Angel; Hopkins, Philip F.

    2011-12-10

    We present Chandra X-ray imaging and spectroscopy for 14 quasars in spatially resolved pairs targeted as part of a complete sample of binary quasars with small transverse separations drawn from Sloan Digital Sky Survey (SDSSDR6) photometry. We measure the X-ray properties of all 14 QSOs, and study the distribution of X-ray and optical-to-X-ray power-law indices in these binary quasars. We find no significant difference when compared with large control samples of isolated quasars, true even for SDSS J1254+0846, discussed in detail in a companion paper, which clearly inhabits an ongoing, pre-coalescence galaxy merger showing obvious tidal tails. We present infrared photometry from our observations with SAO Wide-field InfraRed Camera at the MMT, and from the Wide-field Infrared Survey Explorer Preliminary Data Release, and fit simple spectral energy distributions to all 14 QSOs. We find preliminary evidence that substantial contributions from star formation are required, but possibly no more so than for isolated X-ray-detected QSOs. Sensitive searches of the X-ray images for extended emission and the optical images for optical galaxy excess show that these binary QSOs-expected to occur in strong peaks of the dark matter distribution-are not preferentially found in rich cluster environments. While larger binary QSO samples with richer far-IR and submillimeter multiwavelength data might better reveal signatures of merging and triggering, optical color selection of QSO pairs may be biased against such signatures. X-ray and/or variability selection of QSO pairs, while challenging, should be attempted. We present in an Appendix a primer on X-ray flux and luminosity calculations.

  9. Search for gravitational waves from low mass compact binary coalescence in LIGO's sixth science run and Virgo's science runs 2 and 3

    NASA Astrophysics Data System (ADS)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barker, D.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Basti, A.; Batch, J.; Bauchrowitz, J.; Bauer, Th. S.; Bebronne, M.; Behnke, B.; Beker, M. G.; Bell, A. S.; Belletoile, A.; Belopolski, I.; Benacquista, M.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Breyer, J.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brummit, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet–Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Conte, R.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M.; Coulon, J.-P.; Couvares, P.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, R. M.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daudert, B.; Daveloza, H.; Davier, M.; Davies, G.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; Del Pozzo, W.; del Prete, M.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Paolo Emilio, M.; Di Virgilio, A.; Díaz, M.; Dietz, A.; DiGuglielmo, J.; Donovan, F.; Dooley, K. L.; Dorsher, S.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Endrőczi, G.; Engel, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Farr, W.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Flanigan, M.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P. J.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Ganija, M. R.; Garcia, J.; Garofoli, J. A.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Geng, R.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Gray, N.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Ha, T.; Hage, B.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Hardt, A.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Herrera, V.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hong, T.; Hooper, S.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Izumi, K.; Jacobson, M.; Jang, H.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kamaretsos, I.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Keresztes, Z.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B.; Kim, C.; Kim, D.; Kim, H.; Kim, K.; Kim, N.; Kim, Y.-M.; King, P. J.; Kinsey, M.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kokeyama, K.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lawrie, C.; Lazzarini, A.; Leaci, P.; Lee, C. H.; Lee, H. M.; Leindecker, N.; Leong, J. R.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marandi, A.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Menendez, D.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Moesta, P.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morgia, A.; Mori, T.; Mosca, S.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nash, T.; Naticchioni, L.; Nawrodt, R.; Necula, V.; Nelson, J.; Newton, G.; Nishizawa, A.; Nocera, F.; Nolting, D.; Nuttall, L.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pedraza, M.; Peiris, P.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Phelps, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Pöld, J.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Ramet, C. R.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Redwine, K.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rodriguez, C.; Rodruck, M.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Ryll, H.; Sainathan, P.; Sakosky, M.; Salemi, F.; Samblowski, A.; Sammut, L.; Sancho de la Jordana, L.; Sandberg, V.; Sankar, S.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schlamminger, S.; Schnabel, R.; Schofield, R. M. S.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Smith, R. J. E.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Sperandio, L.; Stefszky, M.; Stein, A. J.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Taffarello, L.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Tseng, K.; Tucker, E.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vitale, S.; Vitale, S.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, X.; Wang, Z.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, H. R.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zadroźny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, F.; Zhang, L.; Zhang, W.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

    2012-04-01

    We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M⊙; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3×10-4, 3.1×10-5, and 6.4×10-6Mpc-3yr-1, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.

  10. Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3

    NASA Technical Reports Server (NTRS)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G. S.; Ceron, E. Amador; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Blackburn, L.; Camp, J. B.; Cannizzo, J.

    2012-01-01

    We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20. 2010. We searched for signals from binaries with total mass between 2 and 25 Stellar Mass; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3 x 10(exp -4), 3.1 x 10(exp -5), and 6.4 x 10(exp -6)/cu Mpc/yr, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.

  11. The evolution of close binary stars

    NASA Astrophysics Data System (ADS)

    Tutukov, A. V.; Cherepashchuk, A. M.

    2016-05-01

    A review of our current understanding of the physics and evolution of close binary stars with various masses under the influence of the nuclear evolution of their components and their magnetic stellar winds is presented. The role of gravitational-wave radiation by close binaries on their evolution and the loss of their orbital angular momentum is also considered. The final stages in the evolution of close binary systems are described. The review also notes the main remaining tasks related to studies of the physics and evolution of various classes of close binaries, including analyses of collisions of close binaries and supermassive black holes in galactic nuclei. Such a collision could lead to the capture of one of the components by the black hole and the acceleration of the remaining component to relativistic speeds.

  12. Eclipsing Binaries: The Primary Distance Indicator

    NASA Astrophysics Data System (ADS)

    Kang, Y.-W.; Hong, K.-S.; Lee, J.

    2007-06-01

    we have investigated how much confidence we can place in eclipsing binaries as distance indicators. The absolute visual magnitudes and the photometric distances of the selected 318 eclipsing binaries were calculated and compared with those calculated from Hipparcos parallaxes. The absolute magnitudes and distances of eclipsing binary systems deduced from analysis of light curves and radial velocity curves are confirmed to have the same accuracy as the Hipparcos parallaxes within an error of 10 percent of the parallax value. This means that photometric distances are accurate enough over a couple thousand parsecs on the basis of the eclipsing binaries used in this paper. The photometric distances of contact binaries show good agreement with those of Rucinski (1996).

  13. Neutron Star Mass Distribution in Binaries

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hwan; Kim, Young-Min

    2016-05-01

    Massive neutron stars with ∼ 2Mʘ have been observed in neutron star-white dwarf binaries. On the other hand, well-measured neutron star masses in double-neutron-star binaries are still consistent with the limit of 1.5Mʘ. These observations raised questions on the neutron star equations of state and the neutron star binary evolution processes. In this presentation, a hypothesis of super-Eddington accretion and its implications are discussed. We argue that a 2Mʘ neutron star is an outcome of the super-Eddington accretion during the evolution of neutron star-white dwarf binary progenitors. We also suggest the possibility of the existence of new type of neutron star binary which consists of a typical neutron star and a massive compact companion (high-mass neutron star or black hole) with M ≥ 2Mʘ.

  14. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  15. EQUILIBRIUM CONFIGURATIONS OF SYNCHRONOUS BINARIES: NUMERICAL SOLUTIONS AND APPLICATION TO KUIPER BELT BINARY 2001 QG{sub 298}

    SciTech Connect

    Gnat, Orly; Sari, Re'em

    2010-08-20

    We present numerical computations of the equilibrium configurations of tidally locked homogeneous binaries rotating in circular orbits. Unlike the classical Roche approximations, we self-consistently account for the tidal and rotational deformations of both components, and relax the assumptions of ellipsoidal configurations and Keplerian rotation. We find numerical solutions for mass ratios q between 10{sup -3} and 1, starting at a small angular velocity for which tidal and rotational deformations are small, and following a sequence of increasing angular velocities. Each series terminates at an appropriate 'Roche limit', above which no equilibrium solution can be found. Even though the Roche limit is crossed before the 'Roche lobe' is filled, any further increase in the angular velocity will result in mass-loss. For close, comparable-mass binaries, we find that local deviations from ellipsoidal forms may be as large as 10%-20%, and departures from Keplerian rotation are significant. We compute the light curves that arise from our equilibrium configurations, assuming their distance is >>1 AU (e.g., in the Kuiper Belt). We consider both backscatter (proportional to the projected area) and diffuse (Lambert) reflections. Backscatter reflection always yields two minima of equal depths. Diffuse reflection, which is sensitive to the surface curvature, generally gives rise to unequal minima. We find detectable intensity differences of up to 10% between our light curves and those arising from the Roche approximations. Finally, we apply our models to Kuiper Belt binary 2001 QG{sub 298}, and find a nearly edge-on binary with a mass ratio q = 0.93{sup +0.07}{sub -0.03}, angular velocity {omega}{sup 2}/G{rho} = 0.333 {+-} 0.001 (statistical errors only), and pure diffuse reflection. For the observed period of 2001 QG{sub 298}, these parameters imply a bulk density {rho} = 0.72 {+-} 0.04 g cm{sup -3}.

  16. Planar infrared binary phase reflectarray.

    PubMed

    Ginn, James; Lail, Brian; Alda, Javier; Boreman, Glenn

    2008-04-15

    A reflective, binary phase reflectarray is demonstrated in the infrared, at a wavelength of 10.6 microm. The unique aspect of this work, at this frequency band, is that the specific desired phase shift is achieved using an array of subwavelength metallic patches on top of a ground-plane-backed dielectric stand-off layer. This is an alternative to the usual method of constructing a reflective Fresnel zone plate by means of a given thickness of dielectric. This initial demonstration of the reflectarray approach at infrared is significant in that there is inherent flexibility to create a range of phase shifts by varying the dimensions of the patches. This will allow for a multilevel phase distribution, or even a continuous variation of phase, across an optical surface with only two-dimensional lithography, avoiding the need for dielectric height variations. PMID:18414530

  17. Detecting galactic binaries with LISA

    NASA Astrophysics Data System (ADS)

    Cornish, Neil J.; Porter, Edward K.

    2005-09-01

    One of the main sources of gravitational waves for the LISA space-borne interferometer is galactic binary systems. The waveforms for these sources are represented by eight parameters of which four are intrinsic and four are extrinsic to the system. Geometrically, these signals exist in an 8D parameter space. By calculating the metric tensor on this space, we calculate the number of templates needed to search for such sources. We show in this study that below a particular monochromatic frequency of f0 ~ 1.6 × 10-3 Hz we can ignore one of the intrinsic parameters and search over a 7D space. Beyond this frequency, we have a change in dimensionality of the parameter space from 7 to 8 dimensions. This sudden change in dimensionality results in a change in the scaling of template number as a function of the monochromatic frequency from ~f1.250 to ~f5.880.

  18. Normal evaporation of binary alloys

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1972-01-01

    In the study of normal evaporation, it is assumed that the evaporating alloy is homogeneous, that the vapor is instantly removed, and that the alloy follows Raoult's law. The differential equation of normal evaporation relating the evaporating time to the final solute concentration is given and solved for several important special cases. Uses of the derived equations are exemplified with a Ni-Al alloy and some binary iron alloys. The accuracy of the predicted results are checked by analyses of actual experimental data on Fe-Ni and Ni-Cr alloys evaporated at 1600 C, and also on the vacuum purification of beryllium. These analyses suggest that the normal evaporation equations presented here give satisfactory results that are accurate to within an order of magnitude of the correct values, even for some highly concentrated solutions. Limited diffusion and the resultant surface solute depletion or enrichment appear important in the extension of this normal evaporation approach.

  19. Record-Breaking Eclipsing Binary

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two eclipses are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two eclipses. (The blue KELT observations during the eclipse show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the eclipse last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind

  20. Sensitive skin.

    PubMed

    Misery, L; Loser, K; Ständer, S

    2016-02-01

    Sensitive skin is a clinical condition defined by the self-reported facial presence of different sensory perceptions, including tightness, stinging, burning, tingling, pain and pruritus. Sensitive skin may occur in individuals with normal skin, with skin barrier disturbance, or as a part of the symptoms associated with facial dermatoses such as rosacea, atopic dermatitis and psoriasis. Although experimental studies are still pending, the symptoms of sensitive skin suggest the involvement of cutaneous nerve fibres and neuronal, as well as epidermal, thermochannels. Many individuals with sensitive skin report worsening symptoms due to environmental factors. It is thought that this might be attributed to the thermochannel TRPV1, as it typically responds to exogenous, endogenous, physical and chemical stimuli. Barrier disruptions and immune mechanisms may also be involved. This review summarizes current knowledge on the epidemiology, potential mechanisms, clinics and therapy of sensitive skin. PMID:26805416

  1. TWENTY-FIVE SUBARCSECOND BINARIES DISCOVERED BY LUNAR OCCULTATIONS

    SciTech Connect

    Richichi, A.; Fors, O.; Cusano, F.; Moerchen, M.

    2013-09-15

    We report on 25 subarcsecond binaries, detected for the first time by means of lunar occultations in the near-infrared (near-IR) as part of a long-term program using the ISAAC instrument at the ESO Very Large Telescope. The primaries have magnitudes in the range K = 3.8-10.4, and the companions in the range K = 6.4-12.1. The magnitude differences have a median value of 2.8, with the largest being 5.4. The projected separations are in the range 6-748 mas and with a median of 18 mas, or about three times less than the diffraction limit of the telescope. Among our binary detections are a pre-main-sequence star and an enigmatic Mira-like variable previously suspected to have a companion. Additionally, we quote an accurate first-time near-IR detection of a previously known wider binary. We discuss our findings on an individual basis as far as made possible by the available literature, and we examine them from a statistical point of view. We derive a typical frequency of binarity among field stars of Almost-Equal-To 10%, in the resolution and sensitivity range afforded by the technique ( Almost-Equal-To 0.''003 to Almost-Equal-To 0.''5, and K Almost-Equal-To 12 mag, respectively). This is in line with previous results using the same technique but we point out interesting differences that we can trace up to sensitivity, time sampling, and average distance of the targets. Finally, we discuss the prospects for further follow-up studies.

  2. Characterization of the benchmark binary NLTT 33370 {sup ,}

    SciTech Connect

    Schlieder, Joshua E.; Bonnefoy, Mickaël; Herbst, T. M.; Henning, Thomas; Biller, Beth; Bergfors, Carolina; Brandner, Wolfgang; Lépine, Sébastien; Rice, Emily; Berger, Edo; Skemer, Andrew; Hinz, Philip; Defrère, Denis; Leisenring, Jarron; Chauvin, Gaël; Lagrange, Anne-Marie; Lacour, Sylvestre; Skrutskie, Michael

    2014-03-01

    We confirm the binary nature of the nearby, very low mass (VLM) system NLTT 33370 with adaptive optics imaging and present resolved near-infrared photometry and integrated light optical and near-infrared spectroscopy to characterize the system. VLT-NaCo and LBTI-LMIRCam images show significant orbital motion between 2013 February and 2013 April. Optical spectra reveal weak, gravity-sensitive alkali lines and strong lithium 6708 Å absorption that indicate the system is younger than field age. VLT-SINFONI near-IR spectra also show weak, gravity-sensitive features and spectral morphology that is consistent with other young VLM dwarfs. We combine the constraints from all age diagnostics to estimate a system age of ∼30-200 Myr. The 1.2-4.7 μm spectral energy distribution of the components point toward T {sub eff} = 3200 ± 500 K and T {sub eff} = 3100 ± 500 K for NLTT 33370 A and B, respectively. The observed spectra, derived temperatures, and estimated age combine to constrain the component spectral types to the range M6-M8. Evolutionary models predict masses of 97{sub −48}{sup +41} M{sub Jup} and 91{sub −44}{sup +41} M{sub Jup} from the estimated luminosities of the components. KPNO-Phoenix spectra allow us to estimate the systemic radial velocity of the binary. The Galactic kinematics of NLTT 33370AB are broadly consistent with other young stars in the solar neighborhood. However, definitive membership in a young, kinematic group cannot be assigned at this time and further follow-up observations are necessary to fully constrain the system's kinematics. The proximity, age, and late-spectral type of this binary make it very novel and an ideal target for rapid, complete orbit determination. The system is one of only a few model calibration benchmarks at young ages and VLMs.

  3. Super-resolving angular rotation measurement using binary-outcome homodyne detection.

    PubMed

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Zhang, Jiandong; Cen, Longzhu; Wang, Feng; Zhao, Yuan

    2016-08-01

    There has been much recent interest in high precision angular rotation measurement using photon orbital angular momentum to realize super-resolving angular rotation measurement. It is well known that quantum detection strategies can obtain a quantum-enhanced performance. Here, we prove that binary-outcome homodyne detection method can obtain a narrower signal peak, showing better resolution compared with the existing data processing method. Since the photon loss is unavoidable in the actual non-ideal optical system, this paper further discusses the impact of photon loss on the resolution and sensitivity of angular rotation measurement with binary-outcome homodyne detection method. PMID:27505811

  4. Fully-coherent all-sky search for gravitational-waves from compact binary coalescences

    NASA Astrophysics Data System (ADS)

    Macleod, D.; Harry, I. W.; Fairhurst, S.

    2016-03-01

    We introduce a fully coherent method for searching for gravitational wave signals generated by the merger of black hole and/or neutron star binaries. This extends the coherent analysis previously developed and used for targeted gravitational wave searches to an all-sky, all-time search. We apply the search to one month of data taken during the fifth science run of the LIGO detectors. We demonstrate an increase in sensitivity of 25% over the coincidence search, which is commensurate with expectations. Finally, we discuss prospects for implementing and running a coherent search for gravitational wave signals from binary coalescence in the advanced gravitational wave detector data.

  5. Encounters between binaries and neutron stars

    NASA Technical Reports Server (NTRS)

    Davies, M. B.; Benz, W.; Hills, J. G.

    1993-01-01

    We simulated encounters between a neutron star and primordial and tidal-capture binaries. In the case of encounters involving a tidal-capture binary, comprising a white dwarf and a main-sequence star, we find that most exchange encounters will produce a single merged object with the white dwarf and neutron star engulfed in a common envelope of gas donated by the main-sequence primary of the original binary. A small fraction of exchanges induce a merger of the white dwarf and main-sequence star, with this object being unbound to the neutron star, and the two objects having a large relative speed at infinity. For encounters involving a primordial binary, fewer encounters require the inclusion of hydrodynamical effects. Those involving collisions or close encounters tend to produce a binary comprised of the two merged stars (now forming one star) and the third star. The binaries produced typically have large enough separations to prevent the formation of a single merged object until subsequent stellar evolution of one of the components causes it to fill its Roche lobe. Clean exchanges produce binaries with large eccentricities; they are typically sufficiently wide to avoid circularization.

  6. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.; Chambers, John; Duncan, Martin J.; Adams, Fred

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets within binary star systems, using a new, ultrafast, symplectic integrator that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems and we have begun to delineate the range of parameter space for which this statement is true. Results of our initial simulations of planetary growth around each star in the alpha Centauri system and other 'wide' binary systems, as well as around both stars in very close binary systems, will be presented.

  7. Be/X-Ray Pulsar Binary Science with LOFT

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    Accretion disks are ubiquitous in astronomical sources. Accretion powered pulsars are a good test bed for accretion disk physics, because unlike for other objects, the spin of the neutron star is directly observable allowing us to see the effects of angular momentum transfer onto the pulsar. The combination of a sensitive wide-field monitor and the large area detector on LOFT will enable new detailed studies of accretion powered pulsars which I will review. RXTE observations have shown an unusually high number of Be/X-ray pulsar binaries in the SMC. Unlike binaries in the Milky Way, these systems are all at the same distance, allowing detailed population studies using the sensitive LOFT WFM, potentially providing connections to star formation episodes. For Galactic accreting pulsar systems, LOFT will allow measurement of spectral variations within individual pulses, mapping the accretion column in detail for the first time. LOFT will also provide better constraints on magnetic fields in accreting pulsars, allowing measurements of cyclotron features, observations of transitions into the centrifugal inhibition regime, and monitoring of spin-up rate vs flux correlations. Coordinated multi-wavelength observations are crucial to extracting the best science from LOFT from these and numerous other objects.

  8. In vitro and in vivo targeting imaging of pancreatic cancer using a Fe3O4@SiO2 nanoprobe modified with anti-mesothelin antibody.

    PubMed

    Liu, Fang; Le, Wenjun; Mei, Tianxiao; Wang, Tiegong; Chen, Luguang; Lei, Yi; Cui, Shaobin; Chen, Bingdi; Cui, Zheng; Shao, Chengwei

    2016-01-01

    Pancreatic cancer is a highly malignant disease with a 5-year survival rate <5% mainly due to lack of early diagnosis and effective therapy. In an effort to improve the early diagnostic rate of pancreatic cancer, a nanoprobe Fe3O4@SiO2 modified with anti-mesothelin antibody (A-MFS) was prepared to target cells and tumor tissues highly expressing mesothelin in vitro (human pancreatic cancer cell line SW1990) and in vivo (subcutaneously transplanted tumors) studies. The A-MFS probe was successfully prepared and was spherical and uniform with a hydrodynamic diameter between 110 and 130 nm. Cell Counting Kit-8 testing indicated that A-MFS was nontoxic in vitro and in vivo studies. The in vitro study showed that the A-MFS probe specifically targeted SW1990 cells with high mesothelin expression. The in vivo study was conducted in Siemens 3.0 T magnetic resonance imaging. The average T2-weighted signal values of the xenografts were 966.533±31.56 before injecting A-MFS and 691.133±56.84 before injecting saline solution. After injection of 0.1 mL A-MFS via nude mouse caudal vein for 2.5 hours, the average T2-weighted signal of the xenograft decreased by 342.533±42.6. The signal value decreased by -61.233±33.9 and -58.7±19.4 after injection of the saline and Fe3O4@SiO2. The decrease of tumor signal by A-MFS was much more significant than that by saline and Fe3O4@SiO2 (P<0.05). The results demonstrated the high stability and nontoxicity of A-MFS, which effectively targeted pancreatic cancer in vitro and in vivo. A-MFS is a promising agent for diagnosis of pancreatic cancer. PMID:27274243

  9. In situ optical sequencing and structure analysis of a trinucleotide repeat genome region by localization microscopy after specific COMBO-FISH nano-probing

    NASA Astrophysics Data System (ADS)

    Stuhlmüller, M.; Schwarz-Finsterle, J.; Fey, E.; Lux, J.; Bach, M.; Cremer, C.; Hinderhofer, K.; Hausmann, M.; Hildenbrand, G.

    2015-10-01

    Trinucleotide repeat expansions (like (CGG)n) of chromatin in the genome of cell nuclei can cause neurological disorders such as for example the Fragile-X syndrome. Until now the mechanisms are not clearly understood as to how these expansions develop during cell proliferation. Therefore in situ investigations of chromatin structures on the nanoscale are required to better understand supra-molecular mechanisms on the single cell level. By super-resolution localization microscopy (Spectral Position Determination Microscopy; SPDM) in combination with nano-probing using COMBO-FISH (COMBinatorial Oligonucleotide FISH), novel insights into the nano-architecture of the genome will become possible. The native spatial structure of trinucleotide repeat expansion genome regions was analysed and optical sequencing of repetitive units was performed within 3D-conserved nuclei using SPDM after COMBO-FISH. We analysed a (CGG)n-expansion region inside the 5' untranslated region of the FMR1 gene. The number of CGG repeats for a full mutation causing the Fragile-X syndrome was found and also verified by Southern blot. The FMR1 promotor region was similarly condensed like a centromeric region whereas the arrangement of the probes labelling the expansion region seemed to indicate a loop-like nano-structure. These results for the first time demonstrate that in situ chromatin structure measurements on the nanoscale are feasible. Due to further methodological progress it will become possible to estimate the state of trinucleotide repeat mutations in detail and to determine the associated chromatin strand structural changes on the single cell level. In general, the application of the described approach to any genome region will lead to new insights into genome nano-architecture and open new avenues for understanding mechanisms and their relevance in the development of heredity diseases.

  10. In vitro and in vivo targeting imaging of pancreatic cancer using a Fe3O4@SiO2 nanoprobe modified with anti-mesothelin antibody

    PubMed Central

    Liu, Fang; Le, Wenjun; Mei, Tianxiao; Wang, Tiegong; Chen, Luguang; Lei, Yi; Cui, Shaobin; Chen, Bingdi; Cui, Zheng; Shao, Chengwei

    2016-01-01

    Pancreatic cancer is a highly malignant disease with a 5-year survival rate <5% mainly due to lack of early diagnosis and effective therapy. In an effort to improve the early diagnostic rate of pancreatic cancer, a nanoprobe Fe3O4@SiO2 modified with anti-mesothelin antibody (A-MFS) was prepared to target cells and tumor tissues highly expressing mesothelin in vitro (human pancreatic cancer cell line SW1990) and in vivo (subcutaneously transplanted tumors) studies. The A-MFS probe was successfully prepared and was spherical and uniform with a hydrodynamic diameter between 110 and 130 nm. Cell Counting Kit-8 testing indicated that A-MFS was nontoxic in vitro and in vivo studies. The in vitro study showed that the A-MFS probe specifically targeted SW1990 cells with high mesothelin expression. The in vivo study was conducted in Siemens 3.0 T magnetic resonance imaging. The average T2-weighted signal values of the xenografts were 966.533±31.56 before injecting A-MFS and 691.133±56.84 before injecting saline solution. After injection of 0.1 mL A-MFS via nude mouse caudal vein for 2.5 hours, the average T2-weighted signal of the xenograft decreased by 342.533±42.6. The signal value decreased by −61.233±33.9 and −58.7±19.4 after injection of the saline and Fe3O4@SiO2. The decrease of tumor signal by A-MFS was much more significant than that by saline and Fe3O4@SiO2 (P<0.05). The results demonstrated the high stability and nontoxicity of A-MFS, which effectively targeted pancreatic cancer in vitro and in vivo. A-MFS is a promising agent for diagnosis of pancreatic cancer. PMID:27274243

  11. Evaluation of the effects of amyloid β aggregation from seaweed extracts by a microliter-scale high-throughput screening system with a quantum dot nanoprobe.

    PubMed

    Ogara, Toshiki; Takahashi, Tomohito; Yasui, Hajime; Uwai, Koji; Tokuraku, Kiyotaka

    2015-07-01

    Inhibitors of amyloid β (Aβ) aggregation have the potential to serve as lead compounds for anti-Alzheimer's disease (AD) agents because Aβ aggregation is a key step in AD pathogenesis. Recently, we developed a novel microliter-scale high-throughput screening (MSHTS) system for Aβ aggregation inhibitors that applied fluorescence microscopic analysis with quantum dot nanoprobes, and attempted to comprehensively screen the inhibitors from spices using this system (Ishigaki et al., PLoS One, 8, e72992, 2013). In this study, we tried to evaluate the inhibitory activities of 11 seaweed extracts on Aβ aggregation using the MSHTS system. The half-maximal effective concentration (EC50) of the ethanolic extracts from all seaweeds exceeded 4.9 mg/ml, indicating that the extracts inhibit Aβ aggregation although this activity was significantly lower than that displayed by members of the Lamiaceae, a family of herbal spices that showed highest activity among 52 spices tested in our 2013 study. On the other hand, the EC50 of boiling water extracts was 0.013-0.42 mg/ml which was comparable with the EC50 of the extracts from the Lamiaceae family. These results suggest that the extraction efficiency of the inhibitors by boiling water extraction was higher than that by ethanolic extraction. Moreover, analysis of fluorescence micrographs, which were obtained from the MSHTS system, revealed that the morphology of the Aβ aggregates coincubated with boiling water extracts differed from control aggregates, suggesting that the MSHTS system is also useful for screening substances that affect the morphology of aggregates. PMID:25534595

  12. Second Einstein Telescope mock data and science challenge: Low frequency binary neutron star data analysis

    NASA Astrophysics Data System (ADS)

    Meacher, Duncan; Cannon, Kipp; Hanna, Chad; Regimbau, Tania; Sathyaprakash, B. S.

    2016-01-01

    The Einstein Telescope is a conceived third-generation gravitational-wave detector that is envisioned to be an order of magnitude more sensitive than advanced LIGO, Virgo, and Kagra, which would be able to detect gravitational-wave signals from the coalescence of compact objects with waveforms starting as low as 1 Hz. With this level of sensitivity, we expect to detect sources at cosmological distances. In this paper we introduce an improved method for the generation of mock data and analyze it with a new low-latency compact binary search pipeline called gstlal. We present the results from this analysis with a focus on low-frequency analysis of binary neutron stars. Despite compact binary coalescence signals lasting hours in the Einstein Telescope sensitivity band when starting at 5 Hz, we show that we are able to discern various overlapping signals from one another. We also determine the detection efficiency for each of the analysis runs conducted and show a proof of concept method for estimating the number signals as a function of redshift. Finally, we show that our ability to recover the signal parameters has improved by an order of magnitude when compared to the results of the first mock data and science challenge. For binary neutron stars we are able to recover the total mass and chirp mass to within 0.5% and 0.05%, respectively.

  13. Gamma-ray binaries and related systems

    NASA Astrophysics Data System (ADS)

    Dubus, Guillaume

    2013-08-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high- (0.1-100 GeV) and very high-energy (>100 GeV) gamma rays. A new class has emerged called "gamma-ray binaries", since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary ( η Car) have also been detected—"related systems" that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common? What drives their high-energy emission? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as the components revolve on their orbit. I explain the basic ingredients that models of gamma-ray binaries use, the challenges that they currently face, and how they can bring insights into the physics of pulsars. I discuss how gamma-ray emission from microquasars provides a window into the connection between accretion-ejection and acceleration, while η Car and novae raise new questions on the physics of these objects—or on the theory of diffusive shock acceleration. Indeed, explaining the gamma-ray emission from binaries strains our theories of high-energy astrophysical processes, by testing them on scales and in environments that were generally not foreseen, and this is how these detections are most valuable.

  14. Interrupted Binary Mass Transfer in Star Clusters

    NASA Astrophysics Data System (ADS)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  15. Climate Sensitivity

    SciTech Connect

    Lindzen, Richard

    2011-11-09

    Warming observed thus far is entirely consistent with low climate sensitivity. However, the result is ambiguous because the sources of climate change are numerous and poorly specified. Model predictions of substantial warming aredependent on positive feedbacks associated with upper level water vapor and clouds, but models are notably inadequate in dealing with clouds and the impacts of clouds and water vapor are intimately intertwined. Various approaches to measuring sensitivity based on the physics of the feedbacks will be described. The results thus far point to negative feedbacks. Problems with these approaches as well as problems with the concept of climate sensitivity will be described.

  16. Solidification phenomena of binary organic mixtures

    NASA Technical Reports Server (NTRS)

    Chang, K.

    1982-01-01

    The coalescence rates and motion of liquid bubbles in binary organic mixtures were studied. Several factors such as temperature gradient, composition gradient, interfacial tension, and densities of the two phases play important roles in separation of phases of immiscible liquids. An attempt was made to study the effect of initial compositions on separation rates of well-dispersed organic mixtures at different temperatures and, ultimately, on the homogeneity of solidification of the immiscible binary organic liquids. These organic mixtures serve as models for metallic pseudo binary systems under study. Two specific systems were investigated: ethyl salicylate - diethyl glycol and succinonitrile - water.

  17. Spin-orbit coupling in binary asteroids

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc; Naidu, Shantanu P.

    2016-01-01

    We use radar images with decameter resolution to measure the sizes, shapes, spin states, mutual orbits, masses, and densities of components of asteroid binaries and triples. We simulate the spin-orbit dynamics of these systems and map the possible spin configurations of the satellites on surface of section plots. The presence of chaotic regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, delay BYORP-type evolution, and extend the lifetime of binaries.

  18. Contact binary stars as standard candles

    NASA Astrophysics Data System (ADS)

    Klagyivik, P.; Csizmadia, Sz.

    2004-06-01

    Rucinski (1996) suggested to use contact binary stars as standard candles. We investigated the properties of contact binary stars in order to search for possibility of their using as standard candles. For this purpose a catalogue of their light curve solution was compiled and on the basis of the catalogue data we calculated the rate of energy transfer between the two components. This allowed us to determine the mass-luminosity relation of the primary as well as secondary components in a contact binary and using Kepler's third law and the strict geometry a very reliable distance determination method was developed.

  19. Radio Detection of Neutron Star Binary Mergers

    NASA Astrophysics Data System (ADS)

    Bear, Brandon; Cardena, Brett; Dispoto, Dana; Papadopoulos, Joanna; Kavic, Michael; Simonetti, John

    2011-10-01

    Neutron star binary systems lose energy through gravitational radiation, and eventually merge. The gravitational radiation from the merger can be detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO). It is expected that a transient radio pulse will also be produced during the merger event. Detection of such radio transients would allow for LIGO to search for signals within constrained time periods. We calculate the LWA-1 detection rate of transient events from neutron star binary mergers. We calculate the detection rate of transient events from neutron star binary mergers for the Long Wavelength Array and the Eight-meter-wavelength Transient Array.

  20. Variance in binary stellar population synthesis

    NASA Astrophysics Data System (ADS)

    Breivik, Katelyn; Larson, Shane L.

    2016-03-01

    In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

  1. Dynamics of binary asteroids. I - Hill's case

    NASA Astrophysics Data System (ADS)

    Chauvineau, B.; Mignard, F.

    1990-02-01

    The present investigation of the dynamics of hypothesized binary (or multiple) asteroids attempts to evaluate the likelihood of their dynamic stability, giving attention to the trajectories of Hill's (1977) problem (including only the gravitational perturbation of the sun) to define the effects of solar perturbations on the relative motion of a binary asteroid. Only for the cases of close binary asteroids, can the Jacobian constant be unambiguously related to the semimajor axis of a weakly disturbed Keplerian ellipse. A greater likelihood is found for a stable asteroid with retrograde orbit, in both the synodic and the inertial frames, that with direct orbit.

  2. Binary Star database BDB: datasets and services

    NASA Astrophysics Data System (ADS)

    Malkov, O. Yu.; Kaygorodov, P. V.; Koravleva, D. A.; Oblak, E.; Debray, B.

    Description of the Binary star DataBase (BDB, http://bdb.inasan.ru), the world's principal database of binary and multiple systems of all observational types, is presented in the paper. BDB contains data on physical and positional parameters of 100,000 components of 40,000 systems of multiplicity 2 to 20, belonging to various observational types: visual, spectroscopic, eclipsing, etc. Information on these types of binaries is obtained from heterogeneous sources of data astronomical catalogues and surveys. Organization of the information is based on the careful cross-identification of the objects. BDB can be queried by star identifier, coordinates, and other paramete

  3. Measuring the Masses of Ophiuchus Binaries

    NASA Astrophysics Data System (ADS)

    Schaefer, Gail

    2014-02-01

    Our goal is to measure dynamical masses of low-mass (<1 Msun) young (<5 Myr) binary components. We propose to continue mapping the orbits of young pairs using AO imaging. Combined with high-resolution spectroscopy, this will yield mass precisions of <5. This is important to validate and distinguish among theoretical calculations of young star evolution, which are most discrepant for low-mass stars. We target 22 binaries in Ophiuchus with unmapped orbits and 1 binary for which additional astrometry will yield precision values for its masses and distance. We request two half-nights, with LGS and NGS AO using NIRC2 on Keck II.

  4. Robust speech recognition from binary masks.

    PubMed

    Narayanan, Arun; Wang, DeLiang

    2010-11-01

    Inspired by recent evidence that a binary pattern may provide sufficient information for human speech recognition, this letter proposes a fundamentally different approach to robust automatic speech recognition. Specifically, recognition is performed by classifying binary masks corresponding to a word utterance. The proposed method is evaluated using a subset of the TIDigits corpus to perform isolated digit recognition. Despite dramatic reduction of speech information encoded in a binary mask, the proposed system performs surprisingly well. The system is compared with a traditional HMM based approach and is shown to perform well under low SNR conditions. PMID:21110529

  5. Eclipsing binaries in the ASAS survey

    NASA Astrophysics Data System (ADS)

    Nedoroščík, J.; Vaňko, M.; Pribulla, T.

    2014-03-01

    We present a statistical investigation of eclipsing binaries presented in the ASAS (http://www.astrouw.edu.pl/asas/?page=download) survey. Applying the Fourier analysis on the ASAS light curves, we used the relations between coefficients to infer principal properties of eclipsing binaries. The systems with eccentric orbits were found and for the same sample the minimum eccentricity was estimated. We also selected short-period detached eclipsing binaries suitable for the detection of circumbinary exoplanets. Systems with the equal minima depth were also discussed.

  6. Gluten Sensitivity

    MedlinePlus

    Gluten is a protein found in wheat, rye, and barley. It is found mainly in foods but ... products like medicines, vitamins, and supplements. People with gluten sensitivity have problems with gluten. It is different ...

  7. Gluten Sensitivity

    MedlinePlus

    ... have problems with gluten. It is different from celiac disease, an immune disease in which people can't ... the symptoms of gluten sensitivity are similar to celiac disease. They include tiredness and stomachaches. It can cause ...

  8. Pulsars in binary systems: probing binary stellar evolution and general relativity.

    PubMed

    Stairs, Ingrid H

    2004-04-23

    Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system. PMID:15105492

  9. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    SciTech Connect

    Haghighipour, Nader; Kaltenegger, Lisa

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  10. Empirical Treatment Effectiveness Models for Binary Outcomes.

    PubMed

    Dalton, Jarrod E; Dawson, Neal V; Sessler, Daniel I; Schold, Jesse D; Love, Thomas E; Kattan, Michael W

    2016-01-01

    Randomized trials provide strong evidence regarding efficacy of interventions but are limited in their capacity to address potential heterogeneity in effectiveness within broad clinical populations. For example, a treatment that on average is superior may be distinctly worse in certain patients. We propose a technique for using large electronic health registries to develop and validate decision models that measure-for distinct combinations of covariate values-the difference in predicted outcomes among 2 alternative treatments. We demonstrate the methodology in a prototype analysis of in-hospital mortality under alternative revascularization treatments. First, we developed prediction models for a binary outcome of interest for each treatment. Decision criteria were then defined based on the treatment-specific model predictions. Patients were then classified as receiving concordant or discordant care (in relation to the model recommendation), and the association between discordance and outcomes was evaluated. We then present alternative decision criteria and validation methodologies, as well as sensitivity analyses that investigate 1) the imbalance between treatments on observed covariates and 2) the aggregate impact of unobserved covariates. Our methodology supplements population-average clinical trial results by modeling heterogeneity in outcomes according to specific covariate values. It thus allows for assessment of current practice, from which cogent hypotheses for improved care can be derived. Newly emerging large population registries will allow for accurate predictions of outcome risk under competing treatments, as complex functions of predictor variables. Whether or not the models might be used to inform decision making depends on the extent to which important predictors are available. Further work is needed to understand the strengths and limitations of this approach, particularly in relation to those based on randomized trials. PMID:25852080

  11. Prospects for Observing Ultracompact Binaries with Space-Based Gravitational Wave Interferometers and Optical Telescopes

    NASA Technical Reports Server (NTRS)

    Littenberg, T. B.; Larson, S. L.; Nelemans, G.; Cornish, N. J.

    2012-01-01

    Space-based gravitational wave interferometers are sensitive to the galactic population of ultracompact binaries. An important subset of the ultracompact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multimessenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher information matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 deg(exp 2) and bright enough to be detected by a magnitude-limited survey.We find, depending on the choice ofGW detector characteristics, limiting magnitude and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.

  12. A Decade in the Life of the Massive Black-Hole Binary IC10 X-1

    NASA Astrophysics Data System (ADS)

    Laycock, Silas

    2014-11-01

    Chandra thanks to its angular resolution, sensitivity and endurance has been able to monitor individual X-ray binaries in the starburst galaxy IC 10. The WR+BH binary known as IC10 X-1 is regarded as one of the most massive stellar black holes; a class of objects representing the pinnacle of the stellar mass function. BH binaries occupy key roles in seeding SMBHs, producing long GRBs at birth, and gravitational waves at death. We report our use of Chandra to refine the orbital ephemeris of X1 and match-up the radial velocity curve of the optical spectral lines with the X-ray eclipse. The resulting phase offset has fascinating implications for our understanding of the interactions between the WR star, its wind, and the radiation field of the BH.

  13. Assembling the Largest, Most Distant Sample of Halo Wide Binaries for Galactic Structure and Dynamics

    NASA Astrophysics Data System (ADS)

    Coronado, J.; Chanamé, J.

    2015-10-01

    Samples of wide binaries (agtrsim \\ 100\\ AU) are a gold mine for Galactic studies. They have been used on a large list of applications in a diversity of fields. In the dynamical arena, wide binaries provided the first meaningful constraints on the mass and nature of disk dark matter and, more recently, they were used to close the remaining parameter space of MACHO-like halo dark matter not accessible to the micro-lensing campaigns. All these applications were possible when samples of these objects became large enough to not be dominated by random, chance alignments of two unrelated stars projected on the sky. Nevertheless, still today the largest available sample of the particularly valuable halo wide binaries free from selection biases, contains not much more than 100 systems, and conclusions on dark matter are very sensitive to this fact.

  14. Gravitational waves from binary supermassive black holes missing in pulsar observations.

    PubMed

    Shannon, R M; Ravi, V; Lentati, L T; Lasky, P D; Hobbs, G; Kerr, M; Manchester, R N; Coles, W A; Levin, Y; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Dai, S; Keith, M J; Osłowski, S; Reardon, D J; van Straten, W; Toomey, L; Wang, J-B; Wen, L; Wyithe, J S B; Zhu, X-J

    2015-09-25

    Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be <1.0 × 10(-15) with 95% confidence. This limit excludes predicted ranges for A(c,yr) from current models with 91 to 99.7% probability. We conclude that binary evolution is either stalled or dramatically accelerated by galactic-center environments and that higher-cadence and shorter-wavelength observations would be more sensitive to gravitational waves. PMID:26404832

  15. Effect of eccentricity on searches for gravitational waves from coalescing compact binaries in ground-based detectors

    SciTech Connect

    Brown, Duncan A.; Zimmerman, Peter J.

    2010-01-15

    Inspiralling compact binaries are expected to circularize before their gravitational-wave signals reach the sensitive frequency band of ground-based detectors. Current searches for gravitational waves from compact binaries using the LIGO and Virgo detectors therefore use circular templates to construct matched filters. Binary formation models have been proposed which suggest that some systems detectable by the LIGO-Virgo network may have non-negligible eccentricity. We investigate the ability of the restricted 3.5 post-Newtonian order TaylorF2 template bank, used by LIGO and Virgo to search for gravitational waves from compact binaries with masses M{<=}35M{sub {center_dot},} to detect binaries with nonzero eccentricity. We model the gravitational waves from eccentric binaries using the x-model post-Newtonian formalism proposed by Hinder et al.[I. Hinder, F. Hermann, P. Laguna, and D. Shoemaker, arXiv:0806.1037v1]. We find that small residual eccentricities (e{sub 0} < or approx. 0.05 at 40 Hz) do not significantly affect the ability of current LIGO searches to detect gravitational waves from coalescing compact binaries with total mass 2M{sub {center_dot}<}M<15M{sub {center_dot}.} For eccentricities e{sub 0} > or approx. 0.1, the loss in matched filter signal-to-noise ratio due to eccentricity can be significant and so templates which include eccentric effects will be required to perform optimal searches for such systems.

  16. Excited-state proton transfer dynamics of firefly's chromophore D-luciferin in DMSO-water binary mixture.

    PubMed

    Kuchlyan, Jagannath; Banik, Debasis; Roy, Arpita; Kundu, Niloy; Sarkar, Nilmoni

    2014-12-01

    In this article we have investigated intermolecular excited-state proton transfer (ESPT) of firefly's chromophore D-luciferin in DMSO-water binary mixtures using steady-state and time-resolved fluorescence spectroscopy. The unusual behavior of DMSO-water binary mixture as reported by Bagchi et al. (J. Phys. Chem. B 2010, 114, 12875-12882) was also found using D-luciferin as intermolecular ESPT probe. The binary mixture has given evidence of its anomalous nature at low mole fractions of DMSO (below XD = 0.4) in our systematic investigation. Upon excitation of neutral D-luciferin molecule, dual fluorescence emissions (protonated and deprotonated form) are observed in DMSO-water binary mixture. A clear isoemissive point in the time-resolved area normalized emission spectra further indicates two emissive species in the excited state of D-luciferin in DMSO-water binary mixture. DMSO-water binary mixtures of different compositions are fascinating hydrogen bonding systems. Therefore, we have observed unusual changes in the fluorescence emission intensity, fluorescence quantum yield, and fluorescence lifetime of more hydrogen bonding sensitive anionic form of D-luciferin in low DMSO content of DMSO-water binary mixture. PMID:25415652

  17. Simultaneous isolation and detection of circulating tumor cells with a microfluidic silicon-nanowire-array integrated with magnetic upconversion nanoprobes.

    PubMed

    Wang, Chao; Ye, Min; Cheng, Liang; Li, Rui; Zhu, Wenwen; Shi, Zhen; Fan, Chunhai; He, Jinkang; Liu, Jian; Liu, Zhuang

    2015-06-01

    The development of sensitive and convenient methods for detection, enrichment, and analysis of circulating tumor cells (CTCs), which serve as an importance diagnostic indicator for metastatic progression of cancer, has received tremendous attention in recent years. In this work, a new approach characteristic of simultaneous CTC capture and detection is developed by integrating a microfluidic silicon nanowire (SiNW) array with multifunctional magnetic upconversion nanoparticles (MUNPs). The MUNPs were conjugated with anti-EpCAM antibody, thus capable to specifically recognize tumor cells in the blood samples and pull them down under an external magnetic field. The capture efficiency of CTCs was further improved by the integration with a microfluidic SiNW array. Due to the autofluorescence free nature in upconversion luminescence (UCL) imaging, our approach allows for highly sensitive detection of small numbers of tumor cells, which afterward could be collected for further analysis and re-culturing. We have further demonstrated that this approach can be applied to detect CTCs in clinical blood samples from lung cancer patients, and obtained consistent results by analyzing the UCL signals and the clinical outcomes of lung cancer metastasis. Therefore our approach represents a promising platform in CTC capture and detection with potential clinical utilization in cancer diagnosis and prognosis. PMID:25907039

  18. Minima Times of Selected Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Parimucha, S.; Dubovsky, P.; Kudak, V.; Perig, V.

    2016-05-01

    We present 221 CCD minima times of the 76 selected eclipsing binaries obtained during 2013-2016 at Observatory at Kolonica Saddle in Slovakia and Observatory of Laboratory of Space Research, Uzhhorod National University in Ukraine

  19. ROTATIONAL DOPPLER BEAMING IN ECLIPSING BINARIES

    SciTech Connect

    Groot, Paul J.

    2012-01-20

    In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.

  20. Binary NEAs Summary V1.0

    NASA Astrophysics Data System (ADS)

    Pravec, P.; Scheirich, P.

    2006-03-01

    This data set includes a summary table of the characteristics of known binary near-Earth asteroids, compiled by Petr Pravec and Petr Scheirich. A list of references to the original observations is also included.