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Sample records for coordination fluorescent chemosensor

  1. A dithienosilole-based fluorescent chemosensor for multiple logic operations at the molecular level.

    Science.gov (United States)

    Zhang, Chen; Sun, Caixia; Lu, Yahong; Wang, Junxing; He, Xingxing; Lu, Junting; Yin, Shouchun; Qiu, Huayu

    2015-11-05

    A chemosensor consisting of two terpyridines covalently linked to a dithienosilole unit (1) has been synthesized, and its optical and metal sensing properties have been investigated. Due to the metal-organic coordination function, 1 can bind with many transition metal ions and display different fluorescence responses that cause it to function as a "turn-off" fluorescent chemosensor. A significant bathochromic shift in the fluorescence spectra is observed in the presence of Zn(2+). Meanwhile, the emission of 1 is weakened upon exposure to Ag(+) and Fe(2+) and completely quenched by Ni(2+), Co(2+), and Cu(2+). Based on the observed results, several logic gates, such as XNOR, INHIBIT, and IMPLICATION, have been achieved by controlling the chemical inputs. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Nanoparticle-based, organic receptor coupled fluorescent chemosensors for the determination of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navneet, E-mail: navneetkaur@pu.ac.in [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Kaur, Simanpreet; Kaur, Amanpreet [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Saluja, Preeti; Sharma, Hemant [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India); Saini, Anu; Dhariwal, Nisha [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Singh, Ajnesh; Singh, Narinder [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India)

    2014-01-15

    The sensors have been developed using silver nanoparticles coated with organic ligands and are fully characterized with spectroscopic methods. The energy-dispersive X-ray (EDX) analysis revealed the presence of organic receptors on the surface of metal nanoparticles. These chemosensors were tested against a range of biological and environmentally relevant cations in the HEPES buffered DMSO/H{sub 2}O (8:2, v/v) solvent system. The fluorescence intensity of these chemosensors was quenched upon coordination with open shell metal ions such as Cu{sup 2+}/Fe{sup 3+}. Anion recognition properties of the corresponding metal complexes have been studied and the original fluorescence intensity of sensors was restored upon addition of phosphate (0–20 µM). Thus, a highly selective chemosensor has been devised for the micromolar estimation of phosphate in semi-aqueous medium. -- Highlights: • The silver nanoparticles have been decorated with organic receptors for chemosensor applications. • The sensor properties are developed for the estimation of phosphate anion. • Thus the sensor relies on the cation displacement assay. • The phosphate sensing event displays the “ON–OFF–ON” mode of switching in sensor.

  3. Pillararene-based fluorescent chemosensors: recent advances and perspectives.

    Science.gov (United States)

    Chen, Jin-Fa; Lin, Qi; Zhang, You-Ming; Yao, Hong; Wei, Tai-Bao

    2017-12-14

    In 2008, a new class of pillar-shaped supramolecular macrocyclic hosts was reported, known as "pillararenes". Their particular electron-rich cavity and the ease of their functionalization offer possibilities for the design and synthesis of novel fluorescent chemosensors. Subsequently, pillararene-based fluorescent sensors and probes have been rapidly developed. This feature article covers the most recent contributions from the pillararene-based fluorescent sensor field in terms of anion/cation sensing, small molecule recognition, biomolecule detection, fluorescent supramolecular aggregates, and biomedical imaging. Meanwhile, we hope that this feature article will inspire more effort to be devoted to this emerging field.

  4. Fluorescent Chemosensors for Toxic Organophosphorus Pesticides: A Review

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    Kenneth Fletcher

    2010-07-01

    Full Text Available Many organophosphorus (OP based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.

  5. Fluorescent chemosensors for toxic organophosphorus pesticides: a review.

    Science.gov (United States)

    Obare, Sherine O; De, Chandrima; Guo, Wen; Haywood, Tajay L; Samuels, Tova A; Adams, Clara P; Masika, Noah O; Murray, Desmond H; Anderson, Ginger A; Campbell, Keith; Fletcher, Kenneth

    2010-01-01

    Many organophosphorus (OP) based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S) functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O) organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.

  6. Several hemicyanine dyes as fluorescence chemosensors for cyanide anions

    Science.gov (United States)

    Liang, Muhan; Wang, Kangnan; Guan, Ruifang; Liu, Zhiqiang; Cao, Duxia; Wu, Qianqian; Shan, Yanyan; Xu, Yongxiao

    2016-05-01

    Four hemicyanine dyes as chemosensors for cyanide anions were synthesized easily. Their photophysical properties and recognition properties for cyanide anions were investigated. The results indicate that all the dyes can recognize cyanide anions with obvious color, absorption and fluorescence change. The recognition mechanism analysis basing on in situ 1H NMR and Job plot data indicates that to the compounds with hydroxyl group, the recognition mechanism is intramolecular hydrogen bonding interaction. However, to the compounds without hydroxyl group, cyanide anion is bonded to carbon-carbon double bond in conjugated bridge and induces N+ CH3 to neutral NCH3. Fluorescence of the compounds is almost quenched upon the addition of cyanide anions.

  7. Two benzoyl coumarin amide fluorescence chemosensors for cyanide anions

    Science.gov (United States)

    Wang, Zian; Wu, Qianqian; Li, Jiale; Qiu, Shuang; Cao, Duxia; Xu, Yongxiao; Liu, Zhiqiang; Yu, Xueying; Sun, Yatong

    2017-08-01

    Two new benzoyl coumarin amide derivatives with ortho hydroxyl benzoyl as terminal group have been synthesized. Their photophysical properties and recognition properties for cyanide anions in acetonitrile have also been examined. The influence of electron donating diethylamino group in coumarin ring and hydroxyl in benzoyl group on recognition properties was explored. The results indicate that the compounds can recognize cyanide anions with obvious absorption and fluorescence spectral change and high sensitivity. The import of diethylamine group increases smartly the absorption ability and fluorescence intensity of the compound, which allows the recognition for cyanide anions can be observed by naked eyes. The in situ hydrogen nuclear magnetic resonance spectra combining photophysical properties change and job's plot data confirm that Michael addition between the chemosensors and cyanide anions occurs. Molecular conjugation is interrupted, which leads to fluorescence quenching. At the same time, there is a certain extent hydrogen bond reaction between cyanide and hydroxyl group in the compounds, which is beneficial to the recognition.

  8. METAL-CONTAINING CONJUGATED POLYMERS AS FLUORESCENT CHEMOSENSORS IN THE DETECTION OF TOXICANTS

    OpenAIRE

    Fegley, Megan E. A.; Pinnock, Sherryllene S.; Malele, Catherine N.; Jones, Wayne E.

    2012-01-01

    Fluorescent conjugated polymers have received a great deal of recent interest due to their ability to act as chemosensors to detect various chemical species in both environmental and biological systems with sensitivity and selectivity. Examples from the literature include polymer chemosensors that operate on either fluorescence “turn-on” or “turn-off” as mechanisms of sensor response. These responses can be related to either photoinduced electron transfer or electronic energy transfer mechani...

  9. A peptide-based fluorescent chemosensor for measuring cadmium ions in aqueous solutions and live cells.

    Science.gov (United States)

    Wang, Peng; Wu, Jiang; Liu, Lixuan; Zhou, Panpan; Ge, Yushu; Liu, Dan; Liu, Weisheng; Tang, Yu

    2015-11-07

    A novel peptide fluorescent chemosensor (H2L) with a lysine backbone and both -NH2 sites conjugated with cysteine and dansyl groups has been designed and synthesized by solid phase peptide synthesis with Fmoc chemistry. This chemosensor is a promising analytical tool for detecting Cd(2+) based on the photo-induced electron transfer (PET) effect by turn-on response in 100% aqueous solutions. As designed, H2L exhibits excellent cell permeation and low biotoxicity as well as displaying relatively high selectivity and sensitivity. The chemosensor penetrated live HeLa cells and detected intracellular Cd(2+) by turn-on response. The binding stoichiometry and affinity, interference test, pH sensitivity, fluorescence quantum yield, quantum mechanical calculations, lifetimes, and cytotoxicity of the chemosensor H2L to Cd(2+) were also investigated. Moreover, H2L exhibits low biotoxicity with a limit of detection (LOD) for Cd(2+) of about 52 nM, implying that H2L can be used as a highly selective and sensitive peptide fluorescent chemosensor in biological systems.

  10. Highly selective and reversible chemosensor for Pd(2+) detected by fluorescence, colorimetry, and test paper.

    Science.gov (United States)

    Wang, Mian; Liu, Xiaomei; Lu, Huizhe; Wang, Hongmei; Qin, Zhaohai

    2015-01-21

    A "turn-on" fluorescent and colorimetric chemosensor (RBS) for Pd(2+) has been designed and synthesized through introduction of sulfur as a ligand atom to Rhodamine B. RBS exhibits high selectivity (freedom from the interference of Hg(2+ )in particular) and sensitivity toward Pd(2+) with a detection limit as low as 2.4 nM. RBS is also a reversible sensor, and it can be made into test paper to detect Pd(2+) in pure water. Compared to the chemosensors that introduced phosphorus to Rhodamine to detect Pd(2+), RBS can be synthesized more simply and economically.

  11. A novel Lu{sup 3+} fluorescent nano-chemosensor using new functionalized mesoporous structures

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    Hosseini, Morteza, E-mail: smhosseini@khayam.ut.ac.ir [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza; Rafiei-Sarmazdeh, Zahra; Faridbod, Farnoush [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Goldooz, Hassan; Badiei, Alireza [School of Chemistry, University College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Nourozi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Mohammadi Ziarani, Ghodsi [Department of Chemistry, Faculty of Science, Alzahra University, Tehran (Iran, Islamic Republic of)

    2013-04-10

    Graphical abstract: A novel Lu{sup 3+} sensitive fluorescent chemosensor is constructed through the preparation of 8-hydroxyquinoline functionalized mesoporous silica with ordered hexagonal array structure (LUS-SPS-Q). Fluorescence measurements revealed that the emission intensity of the Lu{sup 3+}-bound mesoporous material increases significantly upon addition of various concentrations of Lu{sup 3+}, while the mono-, di-, trivalent cations result in either unchanged or weakened intensities. Highlights: ► 8-Hydroxyquinoline functionalized mesoporous silica is introduced as a selective fluorescent probe for lutetium ions. ► Fluorescent intensity of the chemical probe enhances upon binding to lutetium ions. ► Fluorescence measurements were done in a suspension of mesoporous silica in aqueous solution. -- Abstract: A new Lu{sup 3+} sensitive fluorescent chemosensor is designed using 8-hydroxyquinoline functionalized mesoporous silica with highly ordered structure (LUS-SPS-Q). The characterization of LUS-SPS-Q showed that the organized structure has been preserved after the post grafting procedure. The synthesized material showed a selective interaction with Lu{sup 3+} ion, most probably due to the presence of the fluorophore moiety at its surface. The emission intensity of the Lu{sup 3+}-bound mesoporous material increases with an increase in concentrations of Lu{sup 3+} ion. Addition of other mono-, di-, trivalent ions resulted in insignificant change in the fluorescent intensity. The enhancement of fluorescence is attributed to the strong covalent binding of Lu{sup 3+} ion. The linear response range of Lu{sup 3+} chemo-sensor was from 1.6 × 10{sup −7} to 1.0 × 10{sup −5} mol L{sup −1}. The Limit of detection obtained was 8.2 × 10{sup −8} mol L{sup −1} and the pH range which the proposed chemo-sensor can be applied was 3.3–8.3.

  12. Turn-On Fluorescent Chemosensor for Hg2+ Based on Multivalent Rhodamine Ligands

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    Xuemei Wang

    2012-12-01

    Full Text Available Rhodamine-based fluorescent chemosensors 1 and 2 exhibit selective fluorescence enhancement to Fe3+ and Hg2+ over other metal ions at 580 nm in CH3CN/H2O (3/1, v/v solution. Bis(rhodamine chemosensor 1, under optimized conditions (CH3CN/HEPES buffer (0.02 M, pH = 7.0 (95/5, v/v, shows a high selectivity and sensitivity to Hg2+, with a linear working range of 0–50 μM, a wide pH span of 4–10, and a detection limit of 0.4 μM Hg2+.

  13. A selective calix[6]arene-based fluorescent chemosensor for phosphatidylcholine type lipids.

    Science.gov (United States)

    Brunetti, Emilio; Moerkerke, Steven; Wouters, Johan; Bartik, Kristin; Jabin, Ivan

    2016-11-02

    The development of chemosensors that can selectively detect phosphatidylcholines (PCs) in biological samples is of medical relevance considering the importance of these phospholipids in cell growth and survival. Their selective sensing over phosphatidylethanolamines (PEs) is however a challenging task. We report here on the chemosensing capacities of calix[6]tris-pyrenylurea 1, which is able to selectively interact with phosphatidylcholine-type lipids in organic media. Host 1 also binds them in a biphasic chloroform/water solution, opening the way to the design of selective chemosensors for these lipids in biological media. The results obtained by NMR, fluorescence spectroscopy and modelling studies show that the selectivity is the result of the high degree of complementarity between the lipids' zwitterionic phosphatidylcholine headgroup and the receptor's H-bonding donor site and hydrophobic pocket. The mode of recognition is reminiscent of natural systems, such as human phosphatidylcholine transfer proteins (PC-TPs), validating the biomimetic approach adopted in our work.

  14. New Fluorescent Chemosensors Based on Bio-Inspired Ligands and Macrocycles: From Single Molecules to Nanoparticles

    Science.gov (United States)

    Marques, Elisabete De Jesus Oliveira

    Due to the importance of the development of new fluorescent compounds with multifunctional applications in environmental and analytical sciences, nano-scale technologies and biomedicine, the research summarized in this PhD project was focused on the synthesis of new bio-inspired sensors, containing alanine, trypthophan and cysteine amino acids, provided with benzoxazole chromophores; exploration of its photophysical properties as fluorescence markers and chemosensors, and finally in the synthesis of new gold and silica nanoparticles with emissive properties. At the same time, different macrocyclic compounds bearing anthracene, or furyl, aryl or thienyl moieties linked to an imidazo-aza-crown ether were exploited for the synthesis of solid inorganic complexes and their use as fluorescent chemosensors for metal ions and anions was undertaken. The benzoxazole ring was selected as fluorescence probe for peptide skeleton due to the biological activity, antifungal, antimicrobial and anticancer properties, and also due to the higher emission fluorescence which makes it a good candidate for molecular recognition, biomarkers or biosensors. Several studies on the metal ion association constants and by density functional theory (DFT) were performed. The association of the synthesized compounds to more structured nanoparticles could increase the sensibility of the chemosensor and also its capability for sensing. In our case, incorporation of the cysteine amino acid made them good candidates for linkage to gold surface nanoparticles. However, in same cases due to the energy transfer from the metal core, the emission fluorescence of these decorated nanoparticles was quenched. Taking into account this phenomenon, different commercial light transparent LUDOX(c) silica nanoparticles were prepared and studied, containing the emissive peptides.

  15. A rhodol-based fluorescent chemosensor for hydrazine and its application in live cell bioimaging

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    Tiensomjitr, Khomsan; Noorat, Rattha; Wechakorn, Kanokorn; Prabpai, Samran; Suksen, Kanoknetr; Kanjanasirirat, Phongthon; Pewkliang, Yongyut; Borwornpinyo, Suparerk; Kongsaeree, Palangpon

    2017-10-01

    A rhodol cinnamate fluorescent chemosensor (RC) has been developed for selective detection of hydrazine (N2H4). In aqueous medium, the rhodol-based probe exhibited high selectivity for hydrazine among other molecules. The addition of hydrazine triggered a fluorescence emission with 48-fold enhancement based on hydrazinolysis and a subsequent ring-opening process. The chemical probe also displayed a selective colorimetric response toward N2H4 from colorless solution to pink, readily observed by the naked eye. The detection limit of RC for hydrazine was calculated to be 300 nM (9.6 ppb). RC is membrane permeable and was successfully demonstrated to detect hydrazine in live HepG2 cells by confocal fluorescence microscopy.

  16. Turn-On Fluorescent Chemosensor for Fluoride Based on Pyreneamide Derivative

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Nam Joong; Hong, Sung Won; Hong, Ju Hyun; Jeong, Ju Mi; Nam, Kye Chun [Seoul National University, Seoul (Korea, Republic of)

    2012-01-15

    A new chemosensor with pyreneamide derivative of bipyridine is synthesized. In the free ligand, pyreneamide derivative has nearly no fluorescence in acetonitrile solution. However, in the presence of fluoride ion, a 'turn-on' fluorescence was observed. Simultaneously, the colorless ligand solution became markedly orange when fluoride ion was added to pyreneamide derivative in acetonitrile. This phenomenon suggest that the PET (photoinduced electron transfer) between anion electron and pyrene unit was changed the π-π interaction between bipyridine and pyrene that was modified structure by deprotonation. On account of the important roles of anion in biological, clinical, environmental, catalysis, and chemical processes, the selective and efficient recognition of anion is an area of growing interest in supramolecular chemistry. In particular, the studies of chemosensors toward F{sup -} anion are quite intriguing because of its beneficial effects in human physiology. Also, fluoride is interest due to its established role in dental care and osteoporosis. However, an excess of fluoride ion can lead to fluorosis. Therefore, the development of reliable sensors for F{sup -} is needed for environment and human health care. Color changes that can be detected by the naked eye are widely used as signals for events owing to the inexpensive equipment required or no equipment at all.

  17. A dual-channel fluorescent chemosensor for discriminative detection of glutathione based on functionalized carbon quantum dots.

    Science.gov (United States)

    Huang, Yuanyuan; Zhou, Jin; Feng, Hui; Zheng, Jieyu; Ma, Hui-Min; Liu, Weidong; Tang, Cong; Ao, Hang; Zhao, Meizhi; Qian, Zhaosheng

    2016-12-15

    A convenient, fluorescent dual-channel chemosensor on the basis of bis(3-pyridylmethyl)amine-functionalized carbon quantum dots (BPMA-CQDs) nanoprobe was constructed, and it can discriminatively detect glutathione from its analogues cysteine and homocysteine based on two distinctive strategies. Two distinct fluorescence responses of BPMA-CQDs probe to Cu(II) and Ag(I) were identified and further employed to achieve selective detection of Cu(II) and Ag(I) respectively. Based on the BPMA-CQDs/Cu(II) conjugate, discriminative detection of GSH was achieved in terms of correlation between the amounts of GSH and fluorescence recovery. The addition of GSH into BPMA-CQDs/Cu(II) system induces the reduction of Cu(II) to Cu(I), which could efficiently block PET process resulting in the following fluorescence recovery. Based on the BPMA-CQDs/Ag(I) conjugate, GSH assay could also be established on the basis of fluorescence response to GSH. The introduction of GSH into the preceding system triggers the competitive coordination to Ag(I) between BPMA and GSH, and silver ions are finally taken away by GSH from the probe, where the fluorescence is restored to its original weak state. Both of the detection strategies can achieve discriminative detection of GSH from Cys and Hcy. The assays showed good stability and repeatability, and covered a broad linear range of up to 13.3μM with a lowest detection limit of 42.0nM. Moreover, both of them were utilized to monitor GSH level in live cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Screening of biologically important Zn2 + by a chemosensor with fluorescent turn on-off mechanism

    Science.gov (United States)

    Khan, Tanveer A.; Sheoran, Monika; Nikhil Raj M., Venkata; Jain, Surbhi; Gupta, Diksha; Naik, Sunil G.

    2018-01-01

    Reported herein the synthesis, characterization and biologically important zinc ion binding propensity of a weakly fluorescent chemosensor, 4-methyl-2,6-bis((E)-(2-(4-phenylthiazol-2-yl)hydrazono)methyl)phenol (1). 1H NMR spectroscopic titration experiment reveals the binding knack of 1 to the essential Zn2 +. The photo-physical studies of 1 exhibit an enhancement in the fluorescence by several folds upon binding with the zinc ions attributed to PET-off process, with a binding constant value of 5.22 × 103 M- 1. 1 exhibits an excellent detection range for Zn2 + with lower detection limit value of 2.31 × 10- 8 M. The selectivity of 1 was studied with various mono and divalent metal cations and it was observed that most cations either quenches the fluorescence or remains unchanged except for Cd2 +, which shows a slight enhancement in fluorescence intensity of 1. The ratiometric displacement of Cd2 + ions by Zn2 + ions shows an excellent selectivity towards in-situ detection of Zn2 + ions. Photo-physical studies also support the reversible binding of 1 to Zn2 + ions having on and off mechanism in presence of EDTA. Such recognition of the biologically important zinc ions finds potential application in live cell imaging.

  19. Naphthalenediols: A new class of novel fluorescent chemosensors for selective sensing of Cu{sup 2+} and Ni{sup 2+} in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Kavitha, Ramasamy; Stalin, Thambusamy, E-mail: drstalin76@gmail.com

    2015-02-15

    Naphthalenediols(NDs) such as 1,5-naphthalenediol (1,5-ND) and 2,7-Naphthalenediol (2,7-ND) are found to be potent chemosensor for selective sensing of Cu{sup 2+} and Ni{sup 2+} ions respectively. The sensitivity and selectivity of chemosensors have been studied by incorporating NDs into β-Cyclodextrin (β-CD). The chemosensor behavior of NDs towards various transition metals is studied under selective pH medium. In 1,5-ND, the colorimetric chemosensor behavior has been identified and demonstrated in aqueous medium for the selective detection of Cu{sup 2+} without any modification, likewise 2,7-ND also having sensing ability towards Ni{sup 2+}. The chemosensor probe 1,5-ND showed selective chromogenic behavior towards Cu{sup 2+} ions by changing the colour from pink to purple. No significant colour change is observed upon the addition of other metal ions. The sensing property of naphthalenediols towards metal cations has been studied using UV–vis and fluorescence spectral technique. - highlights: • Naphthalenediols such as 1,5-naphthalenediol and 2,7-Naphthalenediol are acts as a chemosensor for selective sensing of Cu{sup 2+} and Ni{sup 2+} ions. • The binding constants were calculated. • The sensitivity and selectivity of chemosensors have been studied by incorporating 1,5-ND/2,7-ND into β-Cyclodextrin. • UV–vis and fluorescence spectral technique.

  20. A ratiometric fluorescent on-off Zn2+ chemosensor based on a tripropargylamine pyrene azide click adduct.

    Science.gov (United States)

    Ingale, Sachin A; Seela, Frank

    2012-10-19

    A new, easy-to-prepare and highly selective pyrene-linked tris-triazole amine fluorescent chemosensor has been designed from tripropargylamine and pyrene azide using Cu(I)-catalyzed click chemistry. The fluorescence on-off sensor 1 is highly selective for Zn(2+) displaying a ratiometric change in emission. The relative intensity ratio of monomer to excimer fluorescence (M(376)/E(465)) of the sensor increases 80-fold upon the addition of 10 equiv of Zn(2+) ions (with a detection limit of 0.2 μM).

  1. Responsive polymers-based dual fluorescent chemosensors for Zn2+ ions and temperatures working in purely aqueous media.

    Science.gov (United States)

    Liu, Tao; Liu, Shiyong

    2011-04-01

    We report on the fabrication of responsive double hydrophilic block copolymers (DHBCs)-based dual fluorescent chemosensors for Zn(2+) ions and temperatures and investigate the effects of thermo-induced micellization and detection conditions on the probing sensitivity and binding reversibility of Zn(2+) ions. A novel quinoline-based polarity-sensitive and Zn(2+)-recognizing fluorescent monomer (ZQMA, 6) was synthesized at first. Well-defined DHBCs bearing quinoline-based Zn(2+)-recognizing moieties (ZQMA) in the thermoresponsive block, PEG-b-P(MEO(2)MA-co-OEGMA-co-ZQMA), were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEO(2)MA), oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA), and ZQMA in the presence of PEG-based macroRAFT agent. The OEGMA contents in the thermoresponsive block varied in the range of 0-12.0 mol % to tune their lower critical solution temperatures (LCSTs). At 20 °C, almost nonfluorescent PEG-b-P(MEO(2)MA-co-ZQMA) molecularly dissolved in water and can selectively bind with Zn(2+) ions over other common metal ions, leading to prominent fluorescence enhancement due to the coordination of ZQMA with Zn(2+). At a polymer concentration of 0.2 g/L, the Zn(2+) detection limit can be down to ~3.0 nM. PEG-b-P(MEO(2)MA-co-ZQMA) self-assembles into micelles possessing P(MEO(2)MA-co-ZQMA) cores and well-solvated PEG coronas upon heating to above the LCST, and the fluorescence intensity exhibit ~6.0-fold increase due to the fact that ZQMA moieties are now located in a more hydrophobic microenvironment. Compared to the unimer state at 20 °C, although PEG-b-P(MEO(2)MA-co-ZQMA) micelles possess a slightly decreased detection limit for Zn(2+) (~14 nM), reversible binding between ZQMA moieties and Zn(2+) ions at 37 °C can be achieved, as evidenced by the on/off switching of fluorescence emission via the sequential addition of Zn(2+) and EDTA. In vitro fluorescence

  2. A Lanthanide-Based Chemosensor for Bioavailable Fe3+ Using a Fluorescent Siderophore: An Assay Displacement Approach

    Directory of Open Access Journals (Sweden)

    Karl J. Wallace

    2010-02-01

    Full Text Available The measurement of trace analytes in aqueous systems has become increasingly important for understanding ocean primary productivity. In oceanography, iron (Fe is a key element in regulating ocean productivity, microplankton assemblages and has been identified as a causative element in the development of some harmful algal blooms.The chemosenor developed in this study is based on an indicator displacement approach that utilizes time-resolved fluorescence and fluorescence resonance energy transfer as the sensing mechanism to achieve detection of Fe3+ ions as low as 5 nM. This novel approach holds promise for the development of photoactive chemosensors for ocean deployment.

  3. NBD-based fluorescent chemosensor for the selective quantification of copper and sulfide in an aqueous solution and living cells.

    Science.gov (United States)

    Meng, Qingtao; Shi, Yu; Wang, Cuiping; Jia, Hongmin; Gao, Xue; Zhang, Run; Wang, Yongfei; Zhang, Zhiqiang

    2015-03-14

    Chemosensors play important roles in cation and anion recognition in biological, industrial, and environmental processes. Although many efforts have been made to develop artificial fluorescent receptors for Cu(2+) and S(2-), their applications in the detection in bulk solutions are limited. In this work, we report a novel fluorescence chemosensor (NL) based on the 7-nitrobenz-2-oxa-1,3-diazole (NBD) fluorophore for the quantification of Cu(2+) and S(2-) in single intact cells. NL specifically binds to Cu(2+) in the presence of other competing cations, and evident changes in UV-vis and fluorescence spectra in HEPES buffer are noticed. Based on the displacement approach, the selective sense S(2-) with the in situ generated NL-Cu(2+) ensemble gives a remarkable recovery of fluorescence and UV-vis absorption spectra. The detection limits of NL for Cu(2+) and NL-Cu(2+) for S(2-) were estimated to be 1.6 nM and 0.17 μM, respectively. NL and the resultant complex NL-Cu(2+) exhibit low cytotoxicity and cell-membrane permeability, which makes them capable of Cu(2+) and S(2-) imaging and quantification in living MDA-MB-231 cells.

  4. Highly selective fluorescent chemosensor for Zn2+ derived from inorganic-organic hybrid magnetic core/shell Fe3O4@SiO2 nanoparticles.

    Science.gov (United States)

    Wang, Yujiao; Peng, Xiaohong; Shi, Jinmin; Tang, Xiaoliang; Jiang, Jie; Liu, Weisheng

    2012-01-25

    Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn2+ was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe3O4@SiO2 nanoparticles [NPs] (DTH-Fe3O4@SiO2 NPs) using the silanol hydrolysis approach. The DTH-Fe3O4@SiO2 inorganic-organic hybrid material was characterized by transmission electron microscopy, dynamic light scattering, X-ray power diffraction, diffuse reflectance infrared Fourier transform, UV-visible absorption and emission spectrometry. The compound DTH exhibited fluorescence response towards Zn2+ and Mg2+ ions, but the DTH-Fe3O4@SiO2 NPs only effectively recognized Zn2+ ion by significant fluorescent enhancement in the presence of various ions, which is due to the restriction of the N-C rotation of DTH-Fe3O4@SiO2 NPs and the formation of the rigid plane with conjugation when the DTH-Fe3O4@SiO2 is coordinated with Zn2+. Moreover, this DTH-Fe3O4@SiO2 fluorescent chemosensor also displayed superparamagnetic properties, and thus, it can be recycled by magnetic attraction.

  5. A novel and simple fluorescent and colorimetric primary chemosensor based on Congo-Red for sulfite and resultant complex as secondary fluorescent chemosensor towards carbonate ions: Fluorescent probe mimicking INHIBIT logic gate.

    Science.gov (United States)

    Tavallali, Hossein; Deilamy-Rad, Gohar; Parhami, Abolfath; Lohrasbi, Sajedeh

    2016-03-01

    A simple receptor based on Congo-Red (CR) was prepared by complexation of CR into two equivalents of Cu (II) ([CR-(Cu)2]) and it has been designed for detection of sulfite and carbonate ions. This chemosensor exhibits high sensitivity for sulfite over other anions in aqueous buffer solution. It exhibits colorimetric 'naked eye' and fluorometric responses to SO3(2-) which results from the addition of SO3(2)(-) to CR diazo moiety. Hereupon, CO3(2-) greatly limits the fluorescence of the resultant sulfite-receptor complex via a hydrogen bonding interaction ([CR-(Cu)2]-SO3). This system can be applied for selective detection of CO3(2-) in the presence of other anions. The detection limits of SO3(2-), calculated by the colorimetric and fluorometric methods, were found to be 0.07 and 0.09µmolL(-)(1), respectively. The sulfite-receptor complex also displayed the ability to detect up to 0.06µmolL(-)(1) CO3(2-). The fluorescence output mimicked 'INHIBIT' logic gate function. The output was exhibited by the intramolecular charge transfer of the [CR-(Cu)2] probe, and was provided by chemical inputs (SO3(2-) and CO3(2-)). Copyright © 2015 Elsevier B.V. All rights reserved.

  6. A highly selective chemosensor for colorimetric detection of Hg{sup 2+} and fluorescence detection of pH changes in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Kavitha, Ramasamy; Stalin, Thambusamy, E-mail: drstalin76@gmail.com

    2014-05-01

    A naturally existing and unmodified simple chemosensor, 2-hydroxy-1,4-naphthoquinone (2HNQ), was identified and used for both the colorimetric detection of Hg{sup 2+} and the fluorescent (on-off) detection of pH. The distinct color change and quenching of fluorescence emission was visible to the naked eye. More importantly, the chemosensor was used in combination with β-cyclodextrin (β-CD), which enabled the sensor to be solubilized and stabilized in aqueous solutions. The sensor selectively detected Hg{sup 2+} via the stable 1:1 complexation of the CåO and OH groups with Hg{sup 2+} and reflected pH changes in the range from 6 to 12 via a fluorescence on–off response resulting from the deprotonation of the hydroxyl group in 2HNQ. - Highlights: • The 2-Hydroxy-1,4-Naphthoquinone (2HNQ) chemosensor is capable of both colorimetric detection of Hg{sup 2+} and a fluorescence on-off response to pH. • The distinct color change and quenching of fluorescence emission are detectable with the naked eye. • The on– off fluorescence response in the pH range from 6– to 12 is due to the deprotonation of the hydroxyl group in 2HNQ.

  7. Selective and Sensitive Detection of Heavy Metal Ions in 100% Aqueous Solution and Cells with a Fluorescence Chemosensor Based on Peptide Using Aggregation-Induced Emission.

    Science.gov (United States)

    Neupane, Lok Nath; Oh, Eun-Taex; Park, Heon Joo; Lee, Keun-Hyeung

    2016-03-15

    A fluorescent peptidyl chemosensor for the detection of heavy metal ions in aqueous solution as well as in cells was synthesized on the basis of the peptide receptor for the metal ions using an aggregation-induced emission fluorophore. The peptidyl chemosensor (1) bearing tetraphenylethylene fluorophore showed an exclusively selective turn-on response to Hg(2+) among 16 metal ions in aqueous buffered solution containing NaCl. The peptidyl chemosensor complexed Hg(2+) ions and then aggregated in aqueous buffered solution, resulting in the significant enhancement (OFF-On) of emissions at around 470 nm. The fluorescent sensor showed a highly sensitive response to Hg(2+), and about 1.0 equiv of Hg(2+) was enough for the saturation of the emission intensity change. The detection limit (5.3 nM, R(2) = 0.99) of 1 for Hg(2+) ions was lower than the maximum allowable level of Hg(2+) in drinking water by EPA. Moreover, the peptidyl chemosensor penetrated live cells and detected intracellular Hg(2+) ions by the turn-on response.

  8. A new fluorene-based Schiff-base as fluorescent chemosensor for selective detection of Cr3 + and Al3 +

    Science.gov (United States)

    Tajbakhsh, Mahmood; Chalmardi, Gholam Babaei; Bekhradnia, Ahmadreza; Hosseinzadeh, Rahman; Hasani, Nahid; Amiri, Mohammadreza Azizi

    2018-01-01

    2-((9H-fluoren-2-ylimino) methyl)phenol (F3) was synthesized by condensation reaction of 9H-fluoren-2-amine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1H-,13C NMR and molecular mass. F3 exhibits a high selectivity for detection of Cr3 + and Al3 + ions as a fluorescent chemosensor and showed a single emission band at 536 nm upon excitation at 333 nm according to fluorescence emission studies. The addition of Cr3 + and Al3 + make a significant increase in fluorescent intensity at 536 nm in CH3CN, while other metal ions have almost no influence on the fluorescence. The fluorescence enhancement was attributed to the inhibited Cdbnd N isomerization and the obstructed excited state intra-molecular proton transfer (ESIPT) of compound F3. Job's plot and DFT calculations data showed that the binding stoichiometries of F3 with Cr3 + and Al3 + are 2:1. The association constants (Ka) for Cr3 + and Al3 + were calculated and found to be 8.33 × 104 M- 1 and 5.44 × 104 M- 1, respectively. The detection limits were also calculated for Cr3 + and Al3 + and found to be 2.5 × 10- 7 mol/L and 3.1 × 10- 7 mol/L, respectively.

  9. A Cu²⁺-selective fluorescent chemosensor based on BODIPY with two pyridine ligands and logic gate.

    Science.gov (United States)

    Huang, Liuqian; Zhang, Jing; Yu, Xiaoxiu; Ma, Yifan; Huang, Tianjiao; Shen, Xi; Qiu, Huayu; He, Xingxing; Yin, Shouchun

    2015-06-15

    A novel near-infrared fluorescent chemosensor based on BODIPY (Py-1) has been synthesized and characterized. Py-1 displays high selectivity and sensitivity for sensing Cu(2+) over other metal ions in acetonitrile. Upon addition of Cu(2+) ions, the maximum absorption band of Py-1 in CH3CN displays a red shift from 603 to 608 nm, which results in a visual color change from pink to blue. When Py-1 is excited at 600 nm in the presence of Cu(2+), the fluorescent emission intensity of Py-1 at 617 nm is quenched over 86%. Notably, the complex of Py-1-Cu(2+) can be restored with the introduction of EDTA or S(2-). Consequently, an IMPLICATION logic gate at molecular level operating in fluorescence mode with Cu(2+) and S(2-) as chemical inputs can be constructed. Finally, based on the reversible and reproducible system, a nanoscale sequential memory unit displaying "Writing-Reading-Erasing-Reading" functions can be integrated. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A New Sensitive and Selective Off-On Fluorescent Zn2+ Chemosensor Based on 3,3',5,5'-Tetraphenylsubstituted Dipyrromethene.

    Science.gov (United States)

    Bumagina, Natalia A; Antina, Elena V; Nikonova, Anna Yu; Berezin, Mikhail B; Ksenofontov, Alexander A; Vyugin, Anatoly I

    2016-11-01

    3,3',5,5'-Tetraphenyl-2,2'-dipyrromethene was described as a highly sensitive and selective Off-on fluorescent colorimetric chemosensor for Zn2+ based on the chelation-enhanced fluorescence (CHEF) effect. The reaction of dipyrromethene ligand with Zn2+ induces the formation of the [ZnL2] complex, which exhibits the increasing fluorescence in 120 fold compared with ligand in the propanol-1/cyclohexane (1:30) binary mixture. The Zn2+ detection limit was 1.4 × 10-7 М. The UV-Vis and fluorescence spectroscopic studies demonstrated that the dipyrromethene sensor was highly selective toward Zn2+ cations over other metal ions (Na+, Mg2+, Co2+, Ni2+, Fe3+, Cu2+, Mn2+, Cd2+ and Pb2+), excluding Hg2+.

  11. 2-(1,2,3-Triazol-4-yl)pyridine-containing ethynylarenes as selective ‘turn-on’ fluorescent chemosensors for Ni(II)

    Science.gov (United States)

    Christensen, Joseph A.; Fletcher, James T.

    2014-01-01

    A series of ethynylarene compounds containing 2-(1,2,3-triazol-4-yl)pyridine chelating units were studied as fluorescent chemosensors for metal cations in aqueous solution. Analogs possessing two chelating units bridged by either 1,4-diethynylphenyl or 2,7-diethynylnaphthyl subunits displayed large hypsochromic shifts coupled with signal intensification when exposed to increasing concentrations of Ni(II), a unique response among 22 metal cation analytes. This response was shown to be reversible, and is proposed to derive from disruption of aggregate formation upon Ni(II) binding at the peripheral chelating units. PMID:25089063

  12. 2-(1,2,3-Triazol-4-yl)pyridine-containing ethynylarenes as selective 'turn-on' fluorescent chemosensors for Ni(II).

    Science.gov (United States)

    Christensen, Joseph A; Fletcher, James T

    2014-08-01

    A series of ethynylarene compounds containing 2-(1,2,3-triazol-4-yl)pyridine chelating units were studied as fluorescent chemosensors for metal cations in aqueous solution. Analogs possessing two chelating units bridged by either 1,4-diethynylphenyl or 2,7-diethynylnaphthyl subunits displayed large hypsochromic shifts coupled with signal intensification when exposed to increasing concentrations of Ni(II), a unique response among 22 metal cation analytes. This response was shown to be reversible, and is proposed to derive from disruption of aggregate formation upon Ni(II) binding at the peripheral chelating units.

  13. A dual-responsive colorimetric and fluorescent chemosensor based on diketopyrrolopyrrole derivative for naked-eye detection of Fe(3+) and its practical application.

    Science.gov (United States)

    Zhang, Shanshan; Sun, Tao; Xiao, Dejun; Yuan, Fang; Li, Tianduo; Wang, Enhua; Liu, Haixia; Niu, Qingfen

    2018-01-15

    A novel dual-responsive colorimetric and fluorescent chemosensor L based on diketopyrrolopyrrole derivative for Fe(3+) detection was designed and synthesized. In presence of Fe(3+), sensor L displayed strong colorimetric response as amaranth to rose pink and significant fluorescence enhancement and chromogenic change, which served as a naked-eye indicator by an obvious color change from purple to red. The binding constant for L-Fe(3+) complex was found as 2.4×10(4) with the lower detection limit of 14.3nM. The sensing mechanism was investigated in detail by fluorescence measurements, IR and (1)H NMR spectra. Sensor L for Fe(3+) detection also exhibited high anti-interference performance, good reversibility, wide pH response range and instantaneous response time. Furthermore, the sensor L has been used to quantify Fe(3+) ions in practical water samples with good recovery. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A dual-responsive colorimetric and fluorescent chemosensor based on diketopyrrolopyrrole derivative for naked-eye detection of Fe3 + and its practical application

    Science.gov (United States)

    Zhang, Shanshan; Sun, Tao; Xiao, Dejun; Yuan, Fang; Li, Tianduo; Wang, Enhua; Liu, Haixia; Niu, Qingfen

    2018-01-01

    A novel dual-responsive colorimetric and fluorescent chemosensor L based on diketopyrrolopyrrole derivative for Fe3 + detection was designed and synthesized. In presence of Fe3 +, sensor L displayed strong colorimetric response as amaranth to rose pink and significant fluorescence enhancement and chromogenic change, which served as a naked-eye indicator by an obvious color change from purple to red. The binding constant for L-Fe3 + complex was found as 2.4 × 104 with the lower detection limit of 14.3 nM. The sensing mechanism was investigated in detail by fluorescence measurements, IR and 1H NMR spectra. Sensor L for Fe3 + detection also exhibited high anti-interference performance, good reversibility, wide pH response range and instantaneous response time. Furthermore, the sensor L has been used to quantify Fe3 + ions in practical water samples with good recovery.

  15. Heterocyclic ring based colorimetric and fluorescent chemosensor for transition metal ions in an aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Boobalan, Maria susai [Department of Chemistry, St. Joseph' s College (Autonomous), Tiruchirappalli 620002 (India); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2015-02-15

    Heterocyclic ring based R1–R3 have been synthesized from the simple condensation method. R1–R3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R1–R3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R1–R3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R1 and R2 were also successfully demonstrated as a fluorescent probe for detecting Cu{sup 2+} ions in living cells. - highlights: • R1–R3 act as colorimetric and fluorescent sensors for metal ions. • Receptors (R1–R3) detect Cu{sup 2+} ions in aqueous solution at nanomolar levels. • R1 and R2 act as a fluorescent probe for detecting Cu{sup 2+} ions in living cells.

  16. A chromone Schiff-base as Al(III) selective fluorescent and colorimetric chemosensor

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Long; Qin, Jing-can; Li, Tian-rong; Wang, Bao-dui; Yang, Zheng-yin, E-mail: yangzy@lzu.edu.cn

    2014-11-15

    A novel and simple chromone Schiff-base receptor 7-methoxychromone-3-carbaldehyde-(indole-2-formyl) hydrazone (MCIH) was prepared. Among the various metal ions, only Al{sup 3+} induces the fluorescence enhancement and results in “OFF–ON” type sensing with excellent selectivity and high sensitivity in ethanol system. Upon binding of Al{sup 3+}, a significant fluorescence enhancement with an “OFF–ON” ratio over 500-fold was triggered and it features visible light excitation (423 nm) and emission (507 nm) profiles. However, other metal ions had no such significant effect on the fluorescence. Also, MCIH can severe as a highly selective chemodosimeter for Al{sup 3+} with “naked-eye” detection, which is easily observed from colorless to yellow–green. The detection limit of MCIH for Al{sup 3+} detection was as low as 5×10{sup −8} M level. - Highlights: • An easy-to-make colorimetric and fluorescent sensor for Al{sup 3+} was developed. • The sensor exhibits higher selectivity and sensitivity for Al{sup 3+} than other metal ions. • Al{sup 3+} resulted in an instant color change of MCIH from colorless to yellow–green. • The Al{sup 3+} detection limit reaching at 5×10{sup −8} M level in ethanol. • This sensor features visible light excitation (423 nm) and emission (507 nm) profiles.

  17. Analysis of Caffeine in Beverages Using Aspirin as a Fluorescent Chemosensor

    Science.gov (United States)

    Smith, Jordan; Loxley, Kristen; Sheridan, Patrick; Hamilton, Todd M.

    2016-01-01

    Caffeine (1,3,7-trimethylxanthine) is an alkaloid stimulant that is popular in beverages. Fluorescence-coupled methods have been used to measure the caffeine content in coffee, tea, soft drinks, energy drinks, and cosmetics. In this experiment, we have developed a method for detecting caffeine in beverages utilizing the effect of the caffeine…

  18. A novel thiourea-hydrazone-based switch-on fluorescent chemosensor for acetate

    Energy Technology Data Exchange (ETDEWEB)

    Huang Weiwei; Chen Zheng [Department of Chemistry, Nankai University, Tianjin 300071 (China); Lin Hai [Key Laboratory of Functional Polymer Materials of Ministry of Education, Nankai University, Tianjin 300071 (China); Lin Huakuan, E-mail: hklin@nankai.edu.c [Department of Chemistry, Nankai University, Tianjin 300071 (China)

    2011-04-15

    A novel sensor for acetate containing thiourea and hydrazone structure has been synthesized. The anion recognition via hydrogen-bonding interactions could be monitored by anion complexation, which induced changes in UV-vis and fluorescence spectra. In particular, the recognition process could be easily detected by the 'naked-eye'. Further insights to the nature of interactions between receptor 1 and AcO{sup -} were obtained by {sup 1}H NMR titration experiments.

  19. A microscale multi-functional metal-organic framework as a fluorescence chemosensor for Fe(III), Al(III) and 2-hydroxy-1-naphthaldehyde.

    Science.gov (United States)

    Kang, Yang; Zheng, Xiang-Jun; Jin, Lin-Pei

    2016-06-01

    A microscale metal-organic framework [Eu(atpt)1.5(phen)(H2O)]n (H2atpt=2-aminoterephthalic acid, phen=1,10-phenanthroline) (Eu-MOF) was synthesized and characterized by elemental analysis, luminescence spectrum, powder X-ray diffraction, dynamic light scattering and scanning electron microscope. The fluorescence response of Eu-MOF to metal ions and aldehydes showed that Eu-MOF is highly selective to Fe(III), Al(III) and 2-hydroxy-1-naphthaldehyde (2-OH-NA). Eu-MOF could be utilized as a multi-functional fluorescence chemosensor for Fe(III), Al(III) and 2-hydroxy-1-naphthaldehyde (2-OH-NA). The detection limit of Fe(III), Al(III) and 2-OH-NA was 45, 10 and 36μM, respectively. The corresponding sensing mechanisms were explored. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Curcumin as a colorimetric and fluorescent chemosensor for selective recognition of fluoride ion

    Energy Technology Data Exchange (ETDEWEB)

    Wu Fangying, E-mail: fywu@ncu.edu.c [Department of Chemistry and Center of Analysis and Testing, Nanchang University, Nanchang 330031 (China); Sun Meizhen [Department of Chemistry and Center of Analysis and Testing, Nanchang University, Nanchang 330031 (China); Jiangxi Institute of Geological Survey, Nanchang, 330030 (China); Xiang Yanling [Department of Chemistry and Center of Analysis and Testing, Nanchang University, Nanchang 330031 (China); Wu Yumei [Packaging Engineering Institute of Jinan University, Zhuhai 519070 (China); Tong, Du-Qiu [Department of Chemistry and Center of Analysis and Testing, Nanchang University, Nanchang 330031 (China)

    2010-02-15

    The binding properties of curcumin with anions in acetonitrile were examined for the first time by UV-vis absorption and fluorescence spectroscopies. The results showed that curcumin highly and selectively responded to F{sup -} over other anions such as AcO{sup -}, H{sub 2}PO{sub 4}{sup -} and Cl{sup -} because of anionic complex formation via hydrogen bond. Curcumin gave rise to the red-shift of absorption spectra and its fluorescence was quenched with concomitant color change from yellow to purple upon addition of F{sup -}, which was detected by naked eyes. The addition of other anions such as AcO{sup -}, H{sub 2}PO{sub 4}{sup -}, HSO{sub 4}{sup -}, NO{sub 3}{sup -}, Cl{sup -} and Br{sup -} did not result in observable spectral change and solution color change. The binding constant between curcumin and F{sup -} was 2.0x10{sup 5} mol{sup -1} L and the recognizing mechanism was investigated as well.

  1. Naphthalenyl appended semicarbazone as ;turn on; fluorescent chemosensor for selective recognition of fluoride ion

    Science.gov (United States)

    Basheer, Sabeel M.; Haribabu, Jebiti; Bhuvanesh, Nattamai S. P.; Karvembu, Ramasamy; Sreekanth, Anandaram

    2017-10-01

    The reaction of 1-isocyanatonaphthalene with hydrazine hydrate in presence of acetone resulted in the formation of napthyl based semicarbazone (1). The compound has been characterized using UV-Visible, FT-IR, NMR, mass spectroscopic and single crystal X-ray diffraction (XRD) tools. The interaction between 1 and fluoride ion has been investigated by means of UV-Visible and fluorescence spectra. The fluoride ion sensing mechanism of 1 has been studied by hybrid density functional theory (DFT) and time dependent DFT (TD-DFT) methods. The added fluoride ion formed intermolecular hydrogen bonds with the protons of N1sbnd H1 and N2sbnd H2 groups of 1 in the ground state. The N1sbnd H1 proton which is closer to naphthalene moiety prefers to bind fluoride anion in the excited state after deprotonation, which lead to excited state proton transfer (ESPT). The fluoride ion sensing process shows a moderate (31.99 kcal/mol) Gibbs free energy. To understand the dynamic features, the transition state (TS) calculation is performed and the change in entropy is found to be -0.6259 kJ/mol, which shows that the sensing process is thermodynamically allowed.

  2. A new highly selective fluorescent turn-on chemosensor for cyanide anion.

    Science.gov (United States)

    Chen, Yabin; Shi, Wei; Hui, Yonghai; Sun, Xinhua; Xu, Linxian; Feng, Lei; Xie, Zhengfeng

    2015-05-01

    A new simple molecule, 2-((2-phenyl-2H-1,2,3-triazol-4-yl)methylene)malononitrile (M1), was synthesized successfully by the Knoevenagel condensation reaction between 2-phenyl-1,2,3-triazole-4-carboxaldehyde and malononitrile. The receptor M1 is highly sensitive and selective to cyanide anion due to the nucleophilic addition of cyanide anion with M1. Distinct changes on UV-vis and fluorescence spectra can be detected with the addition of cyanide anion to the DMSO solution of M1. Optical properties of M1 were scarcely affected by the addition of other common background anions (F(-), Cl(-), Br(-), I(-), SCN(-), OH(-), CO4(2-), H2PO4(-), SO4(2-), HSO4(-), AcO(-), and NO3(-)) under the same condition. The detection limit of CN(-) reaches ~1.43 μM by M1 and the presence of background anions brought very slight interference for the detection of CN(-). Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Synthesis and Application of an Aldazine-Based Fluorescence Chemosensor for the Sequential Detection of Cu2+ and Biological Thiols in Aqueous Solution and Living Cells

    Directory of Open Access Journals (Sweden)

    Hongmin Jia

    2016-01-01

    Full Text Available A fluorescence chemosensor, 2-hydroxy-1-naphthaldehyde azine (HNA was designed and synthesized for sequential detection of Cu2+ and biothiols. It was found that HNA can specifically bind to Cu2+ with 1:1 stoichiometry, accompanied with a dramatic fluorescence quenching and a remarkable bathochromic-shift of the absorbance peak in HEPES buffer. The generated HNA-Cu2+ ensemble displayed a “turn-on” fluorescent response specific for biothiols (Hcy, Cys and GSH based on the displacement approach, giving a remarkable recovery of fluorescence and UV-Vis spectra. The detection limits of HNA-Cu2+ to Hcy, Cys and GSH were estimated to be 1.5 μM, 1.0 μM and 0.8 μM, respectively, suggesting that HNA-Cu2+ is sensitive enough for the determination of thiols in biological systems. The biocompatibility of HNA towards A549 human lung carcinoma cell, was evaluated by an MTT assay. The capability of HNA-Cu2+ to detect biothiols in live A549 cells was then demonstrated by a microscopy fluorescence imaging assay.

  4. Fast, highly selective and sensitive anionic metal-organic framework with nitrogen-rich sites fluorescent chemosensor for nitro explosives detection.

    Science.gov (United States)

    Wang, Xu-Sheng; Li, Lan; Yuan, Da-Qiang; Huang, Yuan-Biao; Cao, Rong

    2018-02-15

    Developing a highly efficient fluorescent sensor for detection of trace amounts of nitro explosives remains a great challenge. Porous metal-organic frameworks (MOFs) are one class of promising fluorescent sensors towards small molecules. Herein, we constructed an anionic Zn-based MOF FJI-C8 based on π-conjugated aromatic ligand H6TDPAT (2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine) containing nitrogen-rich sites. On account of the high density of uncoordinated N atoms, the high overlap between the emission spectrum of the anionic MOF FJI-C8 and the UV-vis absorption spectrum of the representative nitro explosive 2,4-dinitrophenol (2,4-DNP), and the porosity of the MOF, FJI-C8 is demonstrated to be an excellent chemosensor for 2,4-DNP with fast response time (less than 30s), high selectivity (Ksv=5.11×104M-1 for 2,4-DNP), extra sensitivity (LOD=0.002866mM for 2,4-DNP), low usage amount (0.04mg/mL), good stability and quantitative detection features. To the best of our knowledge, this is the first example for highly selective detection of 2,4-DNP. More importantly, theoretical calculation and control experiments unveiled that the energy transfer is the main mechanism for highly detection of 2,4-DNP. This work will pave the way for designing highly efficient luminescent chemosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Graphene Oxide-terpyridine Conjugate: A Highly Selective Colorimetric and Sensitive Fluorescence Nano-chemosensor for Fe2+ in Aqueous Media

    Directory of Open Access Journals (Sweden)

    Bagher Eftekhari-Sis

    2016-07-01

    Full Text Available A graphene oxide-terpyridine conjugate (GOTC based colorimetric and fluorescent nano-chemosensor was synthesized. It showed high selectivity and sensitivity for Fe2+ and Fe3+ ions in neutral aqueous solution over other metal ions such as Li+, Na+, Ba2+, Ca2+, Al3+, Cd2+, Co2+, Cu2+, Hg2+, Mn2+, Ni2+, Pb2+, Zn2+, Cr3+ and Ag+. In absorption spectra, upon addition of Fe2+ or Fe3+, the sensor displayed a peak at 568 nm, by changing the color of the solution from light pink for GOTC to light magenta and deep magenta for Fe3+ and Fe2+, respectively. Also, the fluorescence studies revealed that, Fe2+, Fe3+ and Co2+ quench the emission of GOTC at 473 nm, while other metal ions do not quench the fluorescence of GOTC in solution. Colorimetric and fluorescence techniques could be used for detection of Fe2+ ion concentration at least about 6-10 μM in water solution. The sensing on test paper was also investigated for the naked-eye detection of Fe2+.

  6. A novel cyanide-selective colorimetric and fluorescent chemosensor: first molecular security keypad lock based on phosphotungstic acid and CN- inputs.

    Science.gov (United States)

    Tavallali, Hossein; Deilamy-Rad, Gohar; Parhami, Abolfath; Hasanli, Nahid

    2014-02-15

    Rhodamine B (RhB) an available dye has been developed as novel and efficient colorimetric and fluorometric chemosensor for cyanide ions in an absolutely aqueous media. The UV-vis absorption and fluorescent emission titrations experiments have been employed to study the sensing process. RhB could act as an efficient "ON-OFF" fluorescent response for phosphotungstic acid (H3PW12O40 or PTA) based on an ion associate process. Also (RhB(+))3 · PTA(3-) could operate as an "OFF-ON" fluorescent sensor for cyanide anions based on a ligand substitution process. It has been identified as highly sensitive probe for CN(-) which responds at 0.3 and 0.04 μmol L(-1) concentration levels by absorption and fluorescent method respectively. Depending upon the sequence of addition of PTA and CN(-) ions into the solution, RhB could be as a molecular security keypad lock with PTA and CN(-) inputs. The ionic inputs to new fluorophore have been mimicked as a superimposed electronic molecular keypad lock. The results were compared successfully (>96%) with the data of a spectrophotometry approved method (EPA 9014-1) for cyanide ions. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Colorimetric and fluorescent chemosensor for highly selective and sensitive relay detection of Cu2 + and H2PO4- in aqueous media

    Science.gov (United States)

    Su, Jun-Xia; Wang, Xiao-Ting; Chang, Jing; Wu, Gui-Yuan; Wang, Hai-Ming; Yao, Hong; Lin, Qi; Zhang, You-Ming; Wei, Tai-Bao

    2017-07-01

    In this manuscript, a new colorimetric and fluorescent chemosensor (T) was designed and synthesized, it could successively detect Cu2 + and H2PO4- in DMSO/H2O (v/v = 9:1, pH = 7.2) buffer solution with high selectivity and sensitivity. When added Cu2 + ions into the solution of T, it showed a color changes from yellow to colorless, meanwhile, the green fluorescence of sensor T quenched. This recognition behavior was not affected in the presence of other cations, including Hg2 +, Ag+, Ca2 +, Co2 +, Ni2 +, Cd2 +, Pb2 +, Zn2 +, Cr3 +, and Mg2 + ions. More interestingly, the Cu2 + ions contain sensor T solution could recover the color and fluorescence upon the addition of H2PO4- anions in the same medium. And other surveyed anions (including F-, Cl-, Br-, I-, AcO-, HSO4-, ClO4-, CN- and SCN-) had nearly no influence on the recognition behavior. The detection limits of T to Cu2 + and T-Cu2 + to H2PO4- were evaluated to be 1.609 × 10- 8 M and 0.994 × 10- 7 M, respectively. In addition, the sensor T also could be served as a recyclable component and the logic gate output was also defined in sensing materials. The test strips based on sensor T were fabricated, which acted as a convenient and efficient Cu2 + and H2PO4- test kits.

  8. A simple, reversible, colorimetric and water-soluble fluorescent chemosensor for the naked-eye detection of Cu2 + in 100% aqueous media and application to real samples

    Science.gov (United States)

    Sun, Tao; Niu, Qingfen; Li, Tianduo; Guo, Zongrang; Liu, Haixia

    2018-01-01

    A simple, reversible, colorimetric and water-soluble fluorescent chemosensor ADA for the naked-eye detection of Cu2 + was developed. Sensor ADA showed high selectivity and sensitivity toward Cu2 + in 100% aqueous media over wide pH range. Sensor ADA exhibited a red-shift in the absorption spectra from 466 to 480 nm that is accompanied by significant color change from light yellow to yellowish brown instantaneously. The Cu2 + recognition is based on the chelation-enhanced fluorescence quenching (CHEQ) effect of the paramagnetic nature. The lowest detection limit is determined to be 15.8 nM, which is much lower than the allowable level of Cu2 + in drinking water set by U.S. Environmental Protection Agency ( 20 μM) and the World Health Organization ( 30 μM). The 1:1 binding process was confirmed by fluorescence measurements, IR analysis and DFT studies. Moreover, sensor ADA was successfully applied for determination of trace level of Cu2 + with 4 reuse cycles in various water samples, which affords promising potential in ion-detection field.

  9. Recognition of switching on or off fluorescence emission spectrum on the Schiff-bases as a Mg2+ chemosensor: A first principle DFT and TD-DFT study

    Science.gov (United States)

    Taherpour, Avat Arman; Jamshidi, Morteza; Rezaei, Omid

    2017-11-01

    Today, due to convenience, rapid diagnosis and etc., chemosensors are widely used to detect metal ions. In the current research, through DFT and TD-DFT methods, 8-hydroxyquinoline-5-carbaldehyde-(benzotriazol-1‧-acetyl) (QCH) ligand was used to identify Mg2+ cation and investigate its fluorescence emission spectrum mechanism. In order to investigate electronic properties, natural bond orbital (NBO) analysis, reduced density gradient (RDG) plots and electron localization function (ELF) as well as, changes in energy gap of HOMO and LUMO orbitals in the ground state, in water solution were used. Energy gap underwent change about ΔE = 0.17 eV in the presence of Mg2+ cation. Using TD-DFT calculations the optical absorption and emission of QCH ligand was investigated in the presence and absence of Mg2+cation. QCH ligand lacks emission spectrum but in the presence of Mg2+cation shows an emission spectrum in the wavelength of λEmi = 611 nm. Using electron-hole theory, photoinduced electron transfer (PET) process and fluorescence emission spectrum mechanism were investigated. Turning on emission spectrum in the presence of Mg2+ cation is due to stopping charge transfer from chelator to fluorophore.

  10. A Highly Selective Naphthalimide-Based Chemosensor: "Naked-Eye" Colorimetric and Fluorescent Turn-On Recognition of Al(3+) and Its Application in Practical Samples, Test Paper and Logic Gate.

    Science.gov (United States)

    Li, Na-Na; Zeng, Shuang; Li, Ming-Qiang; Ma, Yu-Qing; Sun, Xue-Jiao; Xing, Zhi-Yong; Li, Jin-Long

    2017-11-16

    A novel naphthalimide-based colorimetric and fluorescent turn-on chemosensor for Al(3+) was synthesized and characterized with spectroscopic techniques. In MeOH solution, BPAM showed high selectivity and sensitivity to Al(3+) by a 60-fold fluorescence enhancement and blue-shift absorption with visible color changes attributed to the contribution of chelation enhanced fluorescence (CHEF) and inhibition of intramolecular charge transfer (ICT). A 1:1 BPAM-Al(3+) complex confirmed by job's plot and HRMS with a binding constant of 6.37 × 10(4) M(- 1), and the detection limit for Al(3+) was as low as 1.59 × 10(- 7) M. BPAM was successfully applied in real sample detection and assessing the existence of Al(3+) by a colorimetric method on filter paper. Furthermore, the fluorescent signals of BPAM were designed to construct an INHIBIT molecular logic gate.

  11. Fabrication of Polydiacetylene Liposome Chemosensor with Enhanced Fluorescent Self-Amplification and Its Application for Selective Detection of Cationic Surfactants.

    Science.gov (United States)

    Wang, Dong-En; Zhao, Lei; Yuan, Mao-Sen; Chen, Shu-Wei; Li, Tianbao; Wang, Jinyi

    2016-10-07

    Polydiacetylene (PDA) materials have been adopted as one of the powerful conjugated polymers for sensing applications due to their unique optical properties. In this paper, we present a new PDA liposome-based sensor system with enhanced fluorescent self-amplification by tuning a fluorophore fluorescence emission. In this system, a 1,8-naphthalimide derivative employed as a highly fluorescent fluorophore was incorporated into a PDA supermolecule. During the formation of blue PDA liposomes, the fluorescence emission of the fluorophore can be directly quenched, while thermal-induced phase transition of PDA liposomes from blue to red can readily restore this fluorescence emission. These phenomena could be ascribed to the tunable Förster energy transfer between the excited fluorophore and PDA conjugated framework. To demonstrate the sensing performance of this newly prepared PDA liposome-based sensor, the sensor with fluorescent self-amplification was successfully applied for the detection of cationic surfactants (CS). The results show that the PDA liposomes displayed a distinct color change and fluorescence restoration in the presence of cationic surfactant species, and allowed detection of cationic surfactants with high sensitivity and selectivity. The limit of detection for target CS, such as cetyltrimethylammonium bromide (CTAB), can reach as low as 184 nM. Compared to the traditional methods based on colorimetric PDA liposomes, this newly fabricated PDA sensor system was superior for sensitivity. Thus, our findings offer an avenue for the design and development of new types of PDA sensors with enhanced sensitivity.

  12. A novel FRET-based fluorescent chemosensor of β-cyclodextrin derivative for TNT detection in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Lijuan [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); Center of Analytical and Testing, Beihua University, Jilin 132013, P.R China (China); Tong, Cuiyan, E-mail: tongcy959@nenu.edu.cn [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); He, Yao; Liu, Bingxin; Wang, Chunyu; Sha, Jie [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China); Lü, Changli, E-mail: lucl055@nenu.edu.cn [Institute of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2014-02-15

    A new fluorescent sensor based on single water-soluble β-cyclodextrin (β-CD) molecule as the support carrier of donor and acceptor complex was designed, and used for TNT detection by fluorescence resonance energy transfer (FRET). In this sensing platform, per-6-amino-β-CD (per-6-NH{sub 2}-β-CD) was used as the detection vehicle. The probe dye of fluorescein 5(6)-isothiocyanate (FITC) was covalently linked onto the per-6-NH{sub 2}-β-CD rim with the grafting molar ratio of 1:1, the residual amino groups of per-6-NH{sub 2}-β-CD can adsorb TNT molecules by forming Meisenheimer complex (TNT–amine complex) with TNT. The absorbtion spectrum of this complex has a spectral overlapping with the emission of FITC in aqueous solution, so it can strongly suppress the fluorescence emission of the adjacent FITC through FRET on β-CD vehicle. This FRET-based fluorescent sensing technique provides a facile, ultrasensitive and selective detection method for TNT molecule. The observed linear fluorescence intensity change could allow the quantitative detection TNT with the detection limit of 20 nM in water. -- Highlights: • Per-6-NH{sub 2}-β-CD was functionalized with fluorescein 5(6)-isothiocyanate. • The PL quenching of FITC-(NH{sub 2})-CD is sensitive to the content of TNT due to FRET. • The PL sensor allows a quantitative detection TNT with a detection limit of 20 nM. • Our strategy opens up a new perspective in the design of sensor for various analytes.

  13. A highly sensitive turn-on fluorescent chemosensor for recognition of Zn2 + and Hg2 + and applications

    Science.gov (United States)

    Tang, Xu; Han, Juan; Wang, Yun; Bao, Xu; Ni, Liang; Wang, Lei; Li, Longhua

    2017-09-01

    A fluorescence probe has been designed and synthesized, and applied with a combined theoretical and experimental study. Research suggests that the probe can be used to sense Zn2 + and Hg2 + through selective turn-on fluorescence responses in the aqueous HEPES buffer (0.05M, pH = 7.4). The limit of detection (LOD) were determined as 1.46 × 10- 7 M (Zn2 +) and 2.50 × 10- 7 M (Hg2 +). Moreover, based on DFT, the geometry optimizations of probe 1, [1-Hg2 +] complex and [1-Zn2 +] complex were carried out using the Gaussian 09 program, in which the B3LYP function was used. The electronic properties of free probe 1 and the metal complexes were studied based on the Natural Bond Orbital (NBO) analyses. The probe 1 has also been successfully applied to detection of Zn2 + and Hg2 + in living cells.

  14. A calix[2]triazole[2]arene-based fluorescent chemosensor for probing the copper trafficking pathway in Wilson's disease.

    Science.gov (United States)

    Cho, Jihee; Pradhan, Tuhin; Lee, Yun Mi; Kim, Jong Seung; Kim, Sanghee

    2014-11-21

    A pyrenyl-appended calix[2]triazole[2]arene displaying excellent selectivity for Cu(2+) over other metal ions in pyrenyl excimer emission changes was synthesized. The binding mode with Cu(2+) was supported through nuclear magnetic resonance (NMR) studies and density functional theory (DFT) calculations. Fluorescence imaging demonstrates that this new copper sensor is capable of detecting intracellular copper in living cells. Furthermore, through colocalization of the probe with organelle trackers as a function of time, it was observed that copper initially accumulates in lysosomes and then decreases. These results provide evidence for a close relationship between copper and lysosomes in Wilson's disease. This system is the first Cu(2+) ion-induced fluorescent turn-on system used for imaging copper trafficking over time in a Wilson's disease model.

  15. Molecular characteristics of a fluorescent chemosensor for the recognition of ferric ion based on photoresponsive azobenzene derivative

    Science.gov (United States)

    Chi, Zhen; Ran, Xia; Shi, Lili; Lou, Jie; Kuang, Yanmin; Guo, Lijun

    2017-01-01

    Metal ion recognition is of great significance in biological and environmental detection. So far, there is very few research related to the ferric ion sensing based on photoresponsive azobenzene derivatives. In this work, we report a highly selective fluorescent "turn-off" sensor for Fe3 + ions and the molecular sensing characteristics based on an azobenzene derivative, N-(3,4,5-octanoxyphenyl)-N‧-4-[(4-hydroxyphenyl)azophenyl]1,3,4-oxadiazole (AOB-t8). The binding association constant was determined to be 6.07 × 103 M- 1 in ethanol and the stoichiometry ratio of 2:2 was obtained from Job's plot and MS spectra. The AOB-t8 might be likely to form the dimer structure through the chelation of ferric ion with the azobenzene moiety. Meanwhile, it was found that the photoisomerization property of AOB-t8 was regulated by the binding with Fe3 +. With the chelation of Fe3 +, the regulated molecular rigidity and the perturbed of electronic state and molecular geometry was suggested to be responsible for the accelerated isomerization of AOB-t8 to UV irradiation and the increased fluorescence lifetime of both trans- and cis-AOB-t8-Fe(III). Moreover, the reversible sensing of AOB-t8 was successfully observed by releasing the iron ion from AOB-t8-Fe(III) with the addition of citric acid.

  16. A dual analyte fluorescent chemosensor based on a furan-pyrene conjugate for Al3 + & HSO3-

    Science.gov (United States)

    Don, Derin; Velmurugan, K.; Prabhu, J.; Bhuvanesh, N.; Thamilselvan, A.; Nandhakumar, R.

    2017-03-01

    A simple chalcone based dual analyte fluorescent probe FPC for Al3 + and HSO3- ions was developed. FPC detects both the analytes through a "turn off-on" approach and by the PET and ICT mechanism. FPC showed high selectivity and sensitivity for Al3 + and HSO3- ions detection over other interfering and competing metal ions. In addition, the LOD of FPC for sensing Al3 + and HSO3- ions was found to be 1.60 × 10- 7 M and 0.17 × 10- 6 M respectively. An electrochemical desalination technique was employed for the complete removal of Al3 + ions from the environmental water samples by using the probe FPC.

  17. Di- and Triphosphate Recognition and Sensing with Mono- and Dinuclear Fluorescent Zinc(II) Complexes: Clues for the Design of Selective Chemosensors for Anions in Aqueous Media.

    Science.gov (United States)

    Bartoli, Francesco; Bencini, Andrea; Garau, Alessandra; Giorgi, Claudia; Lippolis, Vito; Lunghi, Alessandro; Totti, Federico; Valtancoli, Barbara

    2016-10-10

    The synthesis of a new ligand (L1) containing two 1,4,7-triazacyclononane ([9]aneN 3 ) moieties linked by a 4,5-dimethylenacridine unit is reported. The binding and fluorescence sensing properties toward Cu 2+ , Zn 2+ , Cd 2+ , and Pb 2+ of L1 and receptor L2, composed of two [9]aneN 3 macrocycles bridged by a 6,6''-dimethylen-2,2':6',2''-terpyridine unit, have been studied by coupling potentiometric, UV/Vis absorption, and emission measurements in aqueous media. Both receptors can selectively detect Zn 2+ thanks to fluorescence emission enhancement upon metal binding. The analysis of the binding and sensing properties of the Zn 2+ complexes toward inorganic anions revealed that the dinuclear Zn 2+ complex of L1 selectively binds and senses the triphosphate anion (TP), whereas the mononuclear Zn 2+ complex of L2 displays selective recognition of diphosphate (DP). Binding of TP or DP induces emission quenching of the Zn 2+ complexes with L1 and L2, respectively. These results are exploited to discuss the role played by pH, number of coordinated metal cations, and binding ability of the bridging units in metal and/or anion coordination and sensing. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Study on a highly selective fluorescent chemosensor for Cu{sup 2+} and its direct sensing for proton based on 1,3,4-oxadiazole

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ling [College of Chemistry, Jilin University, Changchun 130024 (China); Gu, Caiying [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); He, Yi [College of Chemistry, Jilin University, Changchun 130024 (China); Wang, Guang, E-mail: wangg923@nenu.edu.cn [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2014-09-15

    A photoinduced electron transfer cation sensor, oxadiazole-bridge-bis(N,N-bis(2-pyridylmethyl)amine), was designed and prepared. This sensor displayed an “off–on–off” fluorescent switch for proton and an “on–off” fluorescent switch for Cu{sup 2+}. The fluorescence emission of the sensor was quenched upon addition of Cu{sup 2+} and proton in CH{sub 3}CN/H{sub 2}O solution (v/v, 4:1) due to electron transfer between the N,N-bis(2-pyridylmethyl)amine and the oxadiazole. The sensor presented high selectivity for Cu{sup 2+} over other metal ions and determined Cu{sup 2+} concentration in a linear fashion from 5×10{sup −7} M to 8×10{sup −5} M. Stern–Volmer analysis showed the binding stoichiometry to be 1:2 (host-guest) with a binding constant of 1.8×10{sup 10} M{sup −2}, calculated using the Benesi–Hilderbrand equation. The response of the sensor to Cu{sup 2+} was instantaneous and reversible, and the usual anions did not influence the selectivity for Cu{sup 2+}. - Highlights: • A new fluorescent sensor based on oxadiazole and N,N-bis-(2-pyridylmethyl)amine was designed. • The sensor displayed sensitive fluorescence response “on–off” to Cu{sup 2+} and “on–off–on” for protons. • Fluorescence intensity showed good linear correlation with Cu{sup 2+} concentration from 5×10{sup −7} M to 8×10{sup −5} M. • The high concentration of metal ions and usual anions did not influence the selectivity for Cu{sup 2+}. • The short response time of the sensor for Cu{sup 2+} (within 20 s) meets practical requirements.

  19. Environment-sensitive benzoxazole based fluorescein derivatives: Synthesis and application to the design of ON–OFF fluorescent chemosensors for microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Vikas; Padalkar, Vikas; Sekar, Nagaiyan, E-mail: nethi.sekar@gmail.com

    2015-02-15

    The intermediate 2-(2′, 4,-dihydroxyphenyl) benzoxazole was used for the synthesis of substituted fluorescein derivatives. Fluorescence behavior of the synthesized fluorescein derivatives was studied under different microenvironments like pH, viscosity, surfactant sodium dodecyl sulfate (SDS) and protein Bovine Serum Albumin (BSA). Further, the fluorescence of these molecules was used for the detection of blood sample. Photophysical properties show that all the fluorescent compounds are very sensitive to pH, and in basic medium these compounds show hyper chromic shift. These compounds are also sensitive to the viscosity of the medium. All the compounds are characterized by FT-IR, H NMR and mass spectral analysis. - Highlights: • Synthesized novel ESIPT inspired compounds which are unknown to this date, synthesis route is very easy. • Existing fluorescein compounds show single absorption in UV region having restricted applications are overcome by introducing ESIPT unit in fluorescein core. • First and unique study of fluorescein compounds having pH sensitive dual absorption–emission characteristics. • Relative fluorescence quantum yield of fluorescein derivatives was investigated.

  20. Pyrene Scaffold as Real-Time Fluorescent Turn-on Chemosensor for Selective Detection of Trace-Level Al(III) and Its Aggregation-Induced Emission Enhancement.

    Science.gov (United States)

    Shyamal, Milan; Mazumdar, Prativa; Maity, Samir; Sahoo, Gobinda P; Salgado-Morán, Guillermo; Misra, Ajay

    2016-01-21

    A pyrene based fluorescent probe, 3-methoxy-2-((pyren-2yl-imino)methyl)phenol (HL), was synthesized via simple one-pot reaction from inexpensive reagents. It exhibited high sensitivity and selectivity toward Al(3+) over other relevant metal ions and also displayed novel aggregation-induced emission enhancement (AIEE) characteristics in its aggregate/solid state. When bound with Al(3+) in 1:1 mode, a significant fluorescence enhancement with a turn-on ratio of over ∼200-fold was triggered via chelation-enhanced fluorescence through sensor complex (Al-L) formation, and amusingly excess addition of Al(3+), dramatic enhancement of fluorescence intensity over manifold through aggregate formation was observed. The 1:1 stoichiometry of the sensor complex (Al-L) was calculated from Job's plot based on UV-vis absorption titration. In addition, the binding site of sensor complex (Al-L) was well-established from the (1)H NMR titrations and also supported by the fluorescence reversibility by adding Al(3+) and EDTA sequentially. Intriguingly, the AIEE properties of HL may improve its impact and studied in CH3CN-H2O mixtures at high water content. To gain insight into the AIEE mechanism of the HL, the size and growth process of particles in different volume percentage of water and acetonitrile mixture were studied using time-resolved photoluminescence, dynamic light scattering, optical microscope, and scanning electron microscope. The molecules of HL are aggregated into ordered one-dimensional rod-shaped microcrystals that show obvious optical waveguide effect.

  1. A novel colorimetric and turn-on fluorescent chemosensor for iron(III) ion detection and its application to cellular imaging

    Science.gov (United States)

    Luo, Aoheng; Wang, Hongqing; Wang, Yuyuan; Huang, Qiao; Zhang, Qin

    2016-11-01

    A novel rhodamine-based dual probe Rh-2 for trivalent ferric ions (Fe3 +) was successfully designed and synthesized, which exhibited a highly sensitive and selective recognition towards Fe3 + with an enhanced fluorescence emission in methanol-water media (v/v = 7/3, pH = 7.2). The probe Rh-2 could be applied to the determination of Fe3 + with a linear range covering from 3.0 × 10- 7 to 1.4 × 10- 5 M and a detection limit of 1.24 × 10- 8 M. Meanwhile, the binding ratio of Rh-2 and Fe3 + was found to be 1:1. Most importantly, the fluorescence and color signal changes of the Rh-2 solution were specific to Fe3 + over other commonly coexistent metal ions. Moreover, the probe Rh-2 has been used to image Fe3 + in living cells with satisfying results.

  2. Bistable Solid-State Fluorescence Switching in Photoluminescent, Infinite Coordination Polymers.

    Science.gov (United States)

    Kim, Jincheol; You, Youngmin; Yoon, Seong-Jun; Kim, Jong H; Kang, Boseok; Park, Sang Kyu; Whang, Dong Ryeol; Seo, Jangwon; Cho, Kilwon; Park, Soo Young

    2017-07-26

    Photo-functional infinite coordinated polymers (ICPs) were synthesized that consist of the photochromic dithienylethene (DTE) and a luminescent bridging unit to give enhanced fluorescence in the solid state. We could fabricate well-ordered micropatterns of these ICPs by a soft-lithographic method, which repeatedly showed high contrast on-off fluorescence switching. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. In Vivo Fluorescent Detection of Fe-S Clusters Coordinated by Human GRX2

    OpenAIRE

    Hoff, Kevin G.; Culler, Stephanie J; Nguyen, Peter Q.; McGuire, Ryan M.; Silberg, Jonathan J.; Smolke, Christina D.

    2009-01-01

    A major challenge to studying Fe-S cluster biosynthesis in higher eukaryotes is the lack of simple tools for imaging metallocluster binding to proteins. We describe the first fluorescent approach for in vivo detection of 2Fe2S clusters that is based upon the complementation of Venus fluorescent protein fragments via human glutaredoxin 2 (GRX2) coordination of a 2Fe2S cluster. We show that Escherichia coli and mammalian cells expressing Venus fragments fused to GRX2 ...

  4. Multiconfigurable logic gates based on fluorescence switching in adaptive coordination polymer nanoparticles.

    Science.gov (United States)

    Pu, Fang; Ju, Enguo; Ren, Jinsong; Qu, Xiaogang

    2014-02-01

    Fluorescence switching of guest molecules confined in coordination polymer nanoparticles (CPNs) generated from nucleotides and lanthanide ions are used to construct multiconfigurable logic gates. Moreover, the potential of the material as fluorescent probe with large Stokes shift is demonstrated for cellular imaging. In this work the logic gate is integrated into the therapeutic agent and this will be highly beneficial in future molecular computing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Highly sensitive multiresponsive chemosensor for selective detection of Hg2+ in natural water and different monitoring environments.

    Science.gov (United States)

    Wu, Dayu; Huang, Wei; Lin, Zhihua; Duan, Chunying; He, Cheng; Wu, Shuo; Wang, Dehui

    2008-08-18

    A new chemosensor RF1 that combines a ferrocene unit and a rhodamine block via the linkage of a carbohydrazone binding unit was designed and prepared for the highly selective detection of Hg (2+) in natural water. This chemosensor displays great brightness and fluorescence enhancement following Hg (2+) coordination within the limit of detection for Hg (2+) at 1 parts per billion (ppb). The fluorescence intensities are nearly proportional to the amount of Hg (2+) at the ppb level. It is capable of distinguishing between the safe and the toxic levels of inorganic mercury in drinking water. Hg (2+)-binding also arouses the absorption of the rhodamine moiety in RF1 significantly with the chromogenic detection limit for Hg (2+) at 50 ppb. The conventional UV-vis spectroscopic method thus has the potential to provide the critical information about the mercury hazard assessment for industrial wastewater discharging. The obvious and characteristic color change of the titration solution from colorless to pink upon the addition of Hg (2+) demonstrates that RF1 can be used for "naked-eye" detection of Hg (2+) in water. The Hg (2+) complexation also causes a significant shift of the redox potential about the ferrocene/ferrocenium couple. The electrochemical responses provide the possibility to quantitative analysis of Hg (2+) at the parts per million (ppm) level. Preliminary investigations in natural water samples including seawater and freshwater indicate that RF1 offers a direct and immediate Hg (2+) detection in complex media, pointing out its potential utility in environment monitoring and assessment. The responses of RF1 are Hg (2+) specific, and the chemosensor exhibits high selectivity toward Hg (2+) over other Group 12 metals, alkali, alkaline earth metals, and most of the divalent first-row transition metals. The RF1-Hg (2+) complex is successfully isolated and the Hg (2+)-binding is reversible. The crystal structure and spectral properties of its congener RF2 that

  6. Fluorescent Sulfur-Tagged Europium(III) Coordination Polymers for Monitoring Reactive Oxygen Species.

    Science.gov (United States)

    Wang, Huai-Song; Bao, Wen-Jing; Ren, Shi-Bin; Chen, Ming; Wang, Kang; Xia, Xing-Hua

    2015-07-07

    Oxidative stress caused by reactive oxygen species (ROS) is harmful to biological systems and implicated in various diseases. A variety of selective fluorescent probes have been developed for detecting ROS to uncover their biological functions. Generally, the preparation of the fluorescent probes usually undergoes multiple synthetic steps, and the successful fluorescent sensing usually relies on trial-and-error tests. Herein we present a simple way to prepare fluorescent ROS probes that can be used both in biological and environmental systems. The fluorescent europium(III) coordination polymers (CPs) are prepared by simply mixing the precursors [2,2'-thiodiacetic acid and Eu(NO3)3·6H2O] in ethanol. Interestingly, with the increase of reaction temperature, the product undergoes a morphological transformation from microcrystal to nanoparticle while the structure and fluorescent properties retain. The fluorescence of the sulfur-tagged europium(III) CPs can be selectively quenched by ROS, and thus, sensitive and selective monitoring of ROS in aerosols by the microcrystals and in live cells by the nanoparticles has been achieved. The results reveal that the sulfur-tagged europium(III) CPs provide a novel sensor for imaging ROS in biological and environmental systems.

  7. Novel optical selective chromone Schiff base chemosensor for Al{sup 3+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chun-jiao; Yang, Zheng-yin, E-mail: yangzy@lzu.edu.cn; Fan, Long; Jin, Xiu-long; An, Jun-mei; Cheng, Xiao-ying; Wang, Bao-dui

    2015-02-15

    A novel Schiff-base fluorescent sensor 7-methoxychromone-3-carbaldehyde-((2′-Benzothiazolylthio)-acetyl) hydrazone (MCAH) was synthesized. The new chemosensor possesses dual PET processes simultaneously introducing by both nitrogen and sulfur donors. Upon binding Al{sup 3+}, a significant fluorescence enhancement with a turn-on ratio over 500-fold was triggered. The detection limit of MCAH for Al{sup 3+} was 3.19×10{sup −8} M. - Highlights: • A novel chemosensor based on multiple PET processes was synthesized by a facile one-step reaction. • The sensor exhibits higher sensitivity for Al{sup 3+} than other metal ions with the detection limit reaching at 10{sup −8} M level in ethanol. • The probe exhibited high selectivity for Al{sup 3+} over other metal ions with 500-fold fluorescence enhancement.

  8. Coordinate-targeted and coordinate-stochastic super-resolution microscopy with the reversibly switchable fluorescent protein Dreiklang.

    Science.gov (United States)

    Jensen, Nickels A; Danzl, Johann G; Willig, Katrin I; Lavoie-Cardinal, Flavie; Brakemann, Tanja; Hell, Stefan W; Jakobs, Stefan

    2014-03-17

    Diffraction-unlimited far-field super-resolution fluorescence (nanoscopy) methods typically rely on transiently transferring fluorophores between two states, whereby this transfer is usually laid out as a switch. However, depending on whether this is induced in a spatially controlled manner using a pattern of light (coordinate-targeted) or stochastically on a single-molecule basis, specific requirements on the fluorophores are imposed. Therefore, the fluorophores are usually utilized just for one class of methods only. In this study we demonstrate that the reversibly switchable fluorescent protein Dreiklang enables live-cell recordings in both spatially controlled and stochastic modes. We show that the Dreiklang chromophore entails three different light-induced switching mechanisms, namely a reversible photochemical one, off-switching by stimulated emission, and a reversible transfer to a long-lived dark state from the S1 state, all of which can be utilized to overcome the diffraction barrier. We also find that for the single-molecule-based stochastic GSDIM approach (ground-state depletion followed by individual molecule return), Dreiklang provides a larger number of on-off localization events as compared to its progenitor Citrine. Altogether, Dreiklang is a versatile probe for essentially all popular forms of live-cell fluorescence nanoscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A turn-on coordination nanoparticle-based fluorescent probe for phosphate in human serum

    Science.gov (United States)

    Lin, Na; Li, Jian; Lu, Zhixiang; Bian, Longchun; Zheng, Liyan; Cao, Qiue; Ding, Zhongtao

    2015-03-01

    Coordination nanoparticles (CNPs) are becoming attractive platforms for chemical sensing applications because their unique adjustable properties offer the opportunity to design various luminescent nanoprobes. Here, we present a CNP-based fluorescent nanoprobe, in which fluorophores (rhodamine B, RB) and quenchers (methylene blue, MB) were spontaneously enfolded by coordination networks self-assembled of adenine, biphenyl-4,4'-dicarboxylic acid (BDA) and zinc ions. The aggregation of fluorophores and quenchers in CNPs resulted in a quenched state fluorescence of RB. RB and MB could be released from CNPs in the presence of phosphate, which triggered the fluorescence of RB. On the basis of recognition-driven disassembly principle, a novel turn-on fluorescent probe for the determination of PO43- with a wide response range (0.5-50 μM) has been successfully applied in the detection of phosphate in human serum samples. This work not only develops a probe for phosphate but also provides a general strategy for designing nanoprobes or nanocarriers towards various targets by altering organic linkers or metal ions.Coordination nanoparticles (CNPs) are becoming attractive platforms for chemical sensing applications because their unique adjustable properties offer the opportunity to design various luminescent nanoprobes. Here, we present a CNP-based fluorescent nanoprobe, in which fluorophores (rhodamine B, RB) and quenchers (methylene blue, MB) were spontaneously enfolded by coordination networks self-assembled of adenine, biphenyl-4,4'-dicarboxylic acid (BDA) and zinc ions. The aggregation of fluorophores and quenchers in CNPs resulted in a quenched state fluorescence of RB. RB and MB could be released from CNPs in the presence of phosphate, which triggered the fluorescence of RB. On the basis of recognition-driven disassembly principle, a novel turn-on fluorescent probe for the determination of PO43- with a wide response range (0.5-50 μM) has been successfully applied in

  10. Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Baoxia [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Huang, Yankai [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Xu; Hao, Yuanqiang [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Ding, Yujie [College of Biochemical Engineering, Anhui Polytechnic University, Wuhu 241000 (China); Wei, Wei; Wang, Qi [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Qu, Peng, E-mail: qupeng0212@163.com [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xu, Maotian, E-mail: xumaotian@sqnc.edu.cn [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

    2016-03-17

    Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg{sup 2+} detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb{sup 3+} from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg{sup 2+} into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg{sup 2+}. As a kind of Hg{sup 2+} nanosensor, the probe exhibited excellent selectivity for Hg{sup 2+} and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg{sup 2+} in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg{sup 2+} was achieved based on time-resolved spectroscopy.

  11. Uranium(VI) coordination polymers with pyromellitate ligand: Unique 1D channel structures and diverse fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingjie, E-mail: yzx@ansto.gov.au [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Bhadbhade, Mohan [Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052 (Australia); Karatchevtseva, Inna [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Price, Jason R. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Liu, Hao [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, PO Box 123, Broadway, Sydney, NSW 2007 (Australia); Zhang, Zhaoming; Kong, Linggen [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Čejka, Jiří [Department of Mineralogy, National Museum, Václavské náměstí, 68, Prague 1, 115 79-CZ (Czech Republic); Lu, Kim; Lumpkin, Gregory R. [Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2015-03-15

    Three new coordination polymers of uranium(VI) with pyromellitic acid (H{sub 4}btca) have been synthesized and structurally characterized. (ED)[(UO{sub 2})(btca)]·(DMSO)·3H{sub 2}O (1) (ED=ethylenediammonium; DMSO=dimethylsulfoxide) has a lamellar structure with intercalation of ED and DMSO. (NH{sub 4}){sub 2}[(UO{sub 2}){sub 6}O{sub 2}(OH){sub 6}(btca)]·~6H{sub 2}O (2) has a 3D framework built from 7-fold coordinated uranyl trinuclear units and btca ligands with 1D diamond-shaped channels (~8.5 Å×~8.6 Å). [(UO{sub 2}){sub 2}(H{sub 2}O)(btca)]·4H{sub 2}O (3) has a 3D network constructed by two types of 7-fold coordinated uranium polyhedron. The unique μ{sub 5}-coordination mode of btca in 3 enables the formation of 1D olive-shaped large channels (~4.5 Å×~19 Å). Vibrational modes, thermal stabilities and fluorescence properties have been investigated. - Graphical abstract: Table of content: three new uranium(VI) coordination polymers with pyromellitic acid (H{sub 4}btca) have been synthesized via room temperature and hydrothermal synthesis methods, and structurally characterized. Two to three dimensional (3D) frameworks are revealed. All 3D frameworks have unique 1D large channels. Their vibrational modes, thermal stabilities and photoluminescence properties have been investigated. - Highlights: • Three new coordination polymers of U(VI) with pyromellitic acid (H{sub 4}btca). • Structures from a 2D layer to 3D frameworks with unique 1D channels. • Unusual µ{sub 5}-(η{sub 1}:η{sub 2}:η{sub 1}:η{sub 2:}η{sub 1}) coordination mode of btca ligand. • Vibrational modes, thermal stabilities and luminescent properties reported.

  12. Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination.

    Science.gov (United States)

    Liu, Baoxia; Huang, Yankai; Zhu, Xu; Hao, Yuanqiang; Ding, Yujie; Wei, Wei; Wang, Qi; Qu, Peng; Xu, Maotian

    2016-03-17

    Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg(2+) detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb(3+) from the quenching effect of O-H vibration in water molecules. The subsequent addition of Hg(2+) into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg(2+). As a kind of Hg(2+) nanosensor, the probe exhibited excellent selectivity for Hg(2+) and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg(2+) in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. A highly selective colorimetric and "turn-on" fluorimetric chemosensor for detecting CN- based on unsymmetrical azine derivatives in aqueous media

    Science.gov (United States)

    Sun, You; Hu, Jing-Han; Qi, Jing; Li, Jian-Bin

    2016-10-01

    A novel highly selective chemosensor S1 for cyanide based on unsymmetrical azine derivative was successfully designed and synthesized, which showed both colorimetric and fluorescence turn-on responses for cyanide ions in aqueous. This structurally simple chemosensor could detect CN- anion over other anions in aqueous solution DMSO/H2O (v/v = 3:2) undergo deprotonation reaction. Results showed that the chemosensor S1 exhibited 50 fold enhancement in fluorescence at 530 nm and showed an obvious change in color from colorless to yellow that could be detected by naked eye under the UV-lamp after the addition of CN- in aqueous solution. Moreover, the detection limit on fluorescence response of the sensor to CN- is down to 6.17 × 10- 8 M by titration method. Test strips based on S1 were obtain, which could be used as a convenient and efficient CN- test kit to detect CN- in aqueous solution.

  14. Flexible and Asymmetric Ligand in Constructing Coordinated Complexes: Synthesis, Crystal Structures and Fluorescent Characterization

    Directory of Open Access Journals (Sweden)

    Jianhua Lin

    2010-12-01

    Full Text Available Flexible and asymmetric ligand L [L = 1-((pyridin-3-ylmethyl-1H-benzotriazole], is used as a basic backbone to construct complicated metal-organic frameworks. Two new polymers, namely, [Ag2(L2(NO32]n (1 and [Ag(L(ClO4]n (2, were synthesized and characterized by X-ray structure analysis and fluorescent spectroscopy. The complex 1 gives an “S” type double helical conformation, whereas complex 2 exhibits a 1D zigzag configuration. Different anions affect the silver coordination geometry and crystal packing topology.

  15. Anion-coordination-induced turn-on fluorescence of an oligourea-functionalized tetraphenylethene in a wide concentration range.

    Science.gov (United States)

    Zhao, Jie; Yang, Dong; Zhao, Yanxia; Yang, Xiao-Juan; Wang, Yao-Yu; Wu, Biao

    2014-06-23

    A tetrakis(bisurea)-decorated tetraphenylethene (TPE) ligand (L(2)) was designed, which, upon coordination with phosphate ions, displays fluorescence "turn-on" over a wide concentration range, from dilute to concentrated solutions and to the solid state. The fluorescence enhancement can be attributed to the restriction of the intramolecular rotation of TPE by anion coordination. The crystal structure of the A4L2 (A=anion) complex of L(2) with monohydrogen phosphate provides direct evidence for the coordination mode of the anion. This "anion-coordination-induced emission" (ACIE) is another approach for fluorescence turn-on in addition to aggregation-induced emission (AIE). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A DFT Study of Pyrrole-Isoxazole Derivatives as Chemosensors for Fluoride Anion

    Directory of Open Access Journals (Sweden)

    Shanshan Tang

    2012-09-01

    Full Text Available The interactions between chemosensors, 3-amino-5-(4,5,6,7-tetrahydro-1H-indol-2-ylisoxazole-4-carboxamide (AIC derivatives, and different anions (F Cl, Br, AcO, and H2PO4 have been theoretically investigated using DFT approaches. It turned out that the unique selectivity of AIC derivatives for F is ascribed to their ability of deprotonating the host sensors. Frontier molecular orbital (FMO analyses have shown that the vertical electronic transitions of absorption and emission for the sensing signals are characterized as intramolecular charge transfer (ICT. The study of substituent effects suggests that all the substituted derivatives are expected to be promising candidates for fluoride chemosensors both in UV-vis and fluorescence spectra except for derivative with benzo[d]thieno[3,2-b]thiophene fragment that can serve as ratiometric fluorescent fluoride chemosensor only.

  17. NATO Advanced Research Workshop on Chemosensors of Ion and Molecule Recognition

    CERN Document Server

    Czarnik, A

    1997-01-01

    In the broad field of supramolecular chemistry, the design and hence the use of chemosensors for ion and molecule recognition have developed at an extroardinary rate. This imaginative and creative area which involves the interface of different disciplines, e.g. organic and inorganic chemistry, physical chemistry, biology, medicine, environmental science, is not only fundamental in nature. It is also clear that progress is most rewarding for several new sensor applications deriving from the specific signal delivered by the analyte-probe interaction. Indeed, if calcium sensing in real time for biological purposes is actually possible, owing to the emergence of efficient fluorescent receptors, other elements can also be specifically detected, identified and finally titrated using tailored chemosensors. Pollutants such as heavy metals or radionuclides are among the main targets since their detection and removal could be envisioned at very low concentrations with, in addition, sensors displaying specific and stron...

  18. A chemosensor showing discriminating fluorescent response for highly selective and nanomolar detection of Cu²⁺ and Zn²⁺ and its application in molecular logic gate.

    Science.gov (United States)

    Fegade, Umesh A; Sahoo, Suban K; Singh, Amanpreet; Singh, Narinder; Attarde, Sanjay B; Kuwar, Anil S

    2015-05-04

    A fluorescent based receptor (4Z)-4-(4-diethylamino)-2-hydroxybenzylidene amino)-1,2dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (receptor 3) was developed for the highly selective and sensitive detection of Cu(2+) and Zn(2+) in semi-aqueous system. The fluorescence of receptor 3 was enhanced and quenched, respectively, with the addition of Zn(2+) and Cu(2+) ions over other surveyed cations. The receptor formed host-guest complexes in 1:1 stoichiometry with the detection limit of 5 nM and 15 nM for Cu(2+) and Zn(2+) ions, respectively. Further, we have effectively utilized the two metal ions (Cu(2+) and Zn(2+)) as chemical inputs for the manufacture of INHIBIT type logic gate at molecular level using the fluorescence responses of receptor 3 at 450 nm. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Optical chemosensors and reagents to detect explosives

    OpenAIRE

    Salinas Soler, Yolanda; Martínez Mañez, Ramón; Marcos Martínez, María Dolores; Sancenón Galarza, Félix; Costero Nieto, Ana Maria; Parra Alvarez, Margarita; Gil Grau, Salvador

    2012-01-01

    This critical review is focused on examples reported from 1947 to 2010 related to the design of chromo-fluorogenic chemosensors and reagents for explosives (141 references). © 2012 The Royal Society of Chemistry. Spanish Government (project MAT2009-14564-C04) Generalitat Valencia (project PROMETEO/2009/016) Spanish Ministry of Science and Innovation Salinas Soler, Y.; Martínez Mañez, R.; Marcos Martínez, MD.; Sancenón Galarza, F.; Costero Nieto, AM.; Parra Alvarez, M.; Gil Grau, S...

  20. 5f state interaction with inner coordination sphere ligands: einsteinium 3+ ion fluorescence in aqueous and organic phases

    Energy Technology Data Exchange (ETDEWEB)

    Beitz, J.V.; Wester, D.W.; Williams, C.W.

    1983-01-01

    The interaction between 5f electron states of einsteinium 3+ ion and coordinated ligands in solution has been probed using laser-induced fluorescence. Aquo einsteinium 3+ ion was observed to fluoresce from its first excited J = 5 state in a broad-band peaking at 9260 wavenumbers. The observed fluorescence lifetimes were 1.05 microseconds and 2.78 microseconds in H/sub 2/O and D/sub 2/O (99+ % D atom), respectively. The non-radiative decay rates derived from the lifetime data are compared with previously reported data for Cm, Sm, Eu, Tb, and Dy aquo 3+ ions. The 5f actinide states exhibit substantially greater non-radiative decay rates than do lanthanide 4f states of similar energy gap. This provides evidence that actinide 5f electrons interact more strongly with their inner coordination sphere than do lanthanide ion 4f electrons. The fluorescence lifetime of einsteinium 3+ ion complexed with 1 formal di(2-ethylhexyl)orthophosphoric acid in h-heptane was 2.34 microseconds. 3 figures, 1 table.

  1. Graphene quantum dots coordinated to mercaptopyridine-substituted phthalocyanines: Characterization and application as fluorescence "turn ON" nanoprobes

    Science.gov (United States)

    Achadu, Ojodomo J.; Nyokong, Tebello

    2017-03-01

    This study reports on the design of novel nanoconjugates of graphene quantum dots (GQDs) and tetra or octa-mercaptopyridine-substituted zinc and aluminium phthalocyanines (Pcs) deployed as fluorescence "turn ON" nanoprobes. The phthalocyanines were separately adsorbed onto the planar structure of graphene quantum dots (GQDs) via π-π stacking interaction to form GQDs-mercaptopyridine Pcs nanoconjugates. The quaternized Pc complexes could also interact with the GQDs through electrostatic attraction due to the positive charges on the Pcs ring substituents and the negative charges on the surface of GQDs. The fluorescence emission of the GQDs was quenched upon coordination to the respective Pcs. However, the fluorescence emission was "turned ON" in the presence of Hg2 + employed as a test analyte. The mechanism of the "turn ON" of the GQDs emission in the nanoconjugates is ascribed to the strong affinity of Hg2 + to bind with the bridging sulfur on the Pcs periphery thereby disrupting the π-π stacking interaction between the GQDs and the Pcs with a consequent "turn ON" of the coordinated GQDs' fluorescence.

  2. Fluorescent and colorimetric sensors for detection of lead, cadmium, and mercury ions.

    Science.gov (United States)

    Kim, Ha Na; Ren, Wen Xiu; Kim, Jong Seung; Yoon, Juyoung

    2012-04-21

    Exposure to even very low levels of lead, cadmium, and mercury ions is known to cause neurological, reproductive, cardiovascular, and developmental disorders, which are more serious problems for children particularly. Accordingly, great efforts have been devoted to the development of fluorescent and colorimetric sensors, which can selectively detect lead, cadmium, and mercury ions. In this critical review, the fluorescent and colorimetric sensors are classified according to their receptors into several categories, including small molecule based sensors, calixarene based chemosensors, BODIPY based chemosensors, polymer based chemosensors, DNA functionalized sensing systems, protein based sensing systems and nanoparticle based sensing systems (197 references). This journal is © The Royal Society of Chemistry 2012

  3. A linear fluorescence-quenching response in an amidine-functionalised solid-state sensor for gas-phase and aqueous CO2 detection.

    Science.gov (United States)

    Das, A; D'Alessandro, D M

    2016-04-28

    An amidine-functionalised metal-organic framework (MOF) was shown to be an effective chemosensor in the presence of gaseous and aqueous phase CO2 by virtue of a quenched fluorescence response. This work demonstrates how multifunctional MOFs with high selectivity for CO2 may be exploited to develop CO2 chemosensors.

  4. Recent Development of Chemosensors Based on Cyanine Platforms.

    Science.gov (United States)

    Sun, Wen; Guo, Shigang; Hu, Chong; Fan, Jiangli; Peng, Xiaojun

    2016-07-27

    The cyanine platforms including cyanine, hemicyanine, and squaraine are good candidates for developing chemosensors because of their excellent photophysical properties, outstanding biocompatibility, and low toxicity to living systems. A huge amount of research work involving chemosensors based on the cyanine platforms has emerged in recent years. This review focuses on the development from 2000 to 2015, in which cyanine, hemicyanine, and squaraine sensors will be separately summarized. In each section, a systematization according to the type of detection mechanism is established. The basic principles about the design of the chemosensors and their applications as bioimaging agents are clearly discussed. In addition, we emphasize the advances that have been made in improving the detection performance through incorporation of the chemosensors into nanoparticles.

  5. Spiropyran-Isoquinoline Dyad as a Dual Chemosensor for Co(II) and In(III) Detection.

    Science.gov (United States)

    Kho, Yong-Min; Shin, Eun Ju

    2017-09-19

    Spiropyran derivatives have been studied as light-regulated chemosensors for a variety of metal cations and anions, but there is little research on chemosensors that simultaneously detect multiple metal cations. In this study, a spiropyran derivative with isoquinoline, SP-IQ, was prepared and it functions investigated as a light-regulated sensor for both Co(2+) and In(3+) cations. A colorless nonfluorescent SP-IQ converts to a pink-colored fluorescent MC-IQ by UV irradiation or standing in the dark, and MC-IQ returns to SP-IQ with visible light. Upon UV irradiation with the Co(2+) cation for 7 min, the stronger absorption at 540 nm and the similar fluorescence intensity at 640 nm are observed, compared to when no metal cation is added, due to the formation of a Co(2+) complex with pink color and pink fluorescence. When placed in the dark with the In(3+) cation for 7 h, the colorless solution of SP-IQ changes to the In(3+) complex with yellow color and pink fluorescence, which shows strong absorption at 410 nm and strong fluorescence at 640 nm. Selective detection of the Co(2+) cation with UV irradiation and the In(3+) cation in the dark could be possible with SP-IQ by both absorption and fluorescence spectroscopy or by the naked eye.

  6. Spiropyran-Isoquinoline Dyad as a Dual Chemosensor for Co(II and In(III Detection

    Directory of Open Access Journals (Sweden)

    Yong-Min Kho

    2017-09-01

    Full Text Available Spiropyran derivatives have been studied as light-regulated chemosensors for a variety of metal cations and anions, but there is little research on chemosensors that simultaneously detect multiple metal cations. In this study, a spiropyran derivative with isoquinoline, SP-IQ, was prepared and it functions investigated as a light-regulated sensor for both Co2+ and In3+ cations. A colorless nonfluorescent SP-IQ converts to a pink-colored fluorescent MC-IQ by UV irradiation or standing in the dark, and MC-IQ returns to SP-IQ with visible light. Upon UV irradiation with the Co2+ cation for 7 min, the stronger absorption at 540 nm and the similar fluorescence intensity at 640 nm are observed, compared to when no metal cation is added, due to the formation of a Co2+ complex with pink color and pink fluorescence. When placed in the dark with the In3+ cation for 7 h, the colorless solution of SP-IQ changes to the In3+ complex with yellow color and pink fluorescence, which shows strong absorption at 410 nm and strong fluorescence at 640 nm. Selective detection of the Co2+ cation with UV irradiation and the In3+ cation in the dark could be possible with SP-IQ by both absorption and fluorescence spectroscopy or by the naked eye.

  7. A New Polymer-Based Fluorescent Chemosensor Incorporating Propane-1,3-Dione and 2,5-Diethynylbenzene Moieties for Detection of Copper(II and Iron(III

    Directory of Open Access Journals (Sweden)

    Dongliang Yang

    2017-07-01

    Full Text Available A novel conjugated polymer (PDBDBM was developed by the polymerization of 1,4-dioctyloxy-2,5-diethynylbenzene with 1,3-bis(4-bromophenylpropane-1,3-dione based on Pd-catalyzed Sonogashira-coupling reaction. The obtained polymer PDBDBM exhibited bright green photoluminescence under UV irradiation. According to the metal ion titration experiments, PDBDBM showed high sensitivity and selectivity for detection of Cu2+ and Fe3+ over other metal ions. The fluorescent detection limits of PDBDBM were calculated to be 5 nM for Cu2+ and 0.4 μM for Fe3+ and the Stern–Volmer quenching constant for Cu2+ and Fe3+ were found to be 1.28 × 108 M−1 and 2.40 × 104 M−1, respectively. These results indicated that the polymer can be used as a potential probe for Cu2+ and Fe3+ detection.

  8. New platinum (II) and palladium (II) complexes of coumarin-thiazole Schiff base with a fluorescent chemosensor properties: Synthesis, spectroscopic characterization, X-ray structure determination, in vitro anticancer activity on various human carcinoma cell lines and computational studies.

    Science.gov (United States)

    Şahin, Ömer; Özdemir, Ümmühan Özmen; Seferoğlu, Nurgül; Genc, Zuhal Karagöz; Kaya, Kerem; Aydıner, Burcu; Tekin, Suat; Seferoğlu, Zeynel

    2018-01-01

    A new coumarin-thiazole based Schiff base (Ligand, L) and its Pd(II), Pt(II) complexes; ([Pd(L) 2 ] and [Pt(L) 2 ]), were synthesized and characterized using spectrophotometric techniques (NMR, IR, UV-vis, LC-MS), magnetic moment, and conductivity measurements. A single crystal X-ray analysis for only L was done. The crystals of L have monoclinic crystal system and P21/c space group. To gain insight into the structure of L and its complexes, we used density functional theory (DFT) method to optimize the molecules. The photophysical properties changes were observed after deprotonation of L with CN - via intermolecular charge transfer (ICT). Additionally, as the sensor is a colorimetric and fluorimetric cyanide probe containing active sites such as coumarin-thiazole and imine (CH=N), it showed fast color change from yellow to deep red in the visible region, and yellow fluorescence after CN - addition to the imine bond, in DMSO. The reaction mechanisms of L with CN - , F - and AcO - ions were evaluated using 1 H NMR shifts. The results showed that, the reaction of L with CN - ion was due to the deprotonation and addition mechanisms at the same time. The anti-cancer activity of L and its Pd(II) and Pt(II) complexes were evaluated in vitro using MTT assay on the human cancer lines MCF-7 (human breast adenocarcinoma), LS174T (human colon carcinoma), and LNCAP (human prostate adenocarcinoma). The anti-cancer effects of L and its complexes, on human cells, were determined by comparing the half maximal inhibitory concentration (IC 50 ) values. The activity results showed that, the Pd(II) complex of L has higher anti-tumor effect than L and its Pt(II) complex against the tested human breast adenocarcinoma (MCF-7), human prostate adenocarcinoma (LNCAP), and human colon carcinoma (LS174T) cell lines. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Rectangular coordination polymer nanoplates: large-scale, rapid synthesis and their application as a fluorescent sensing platform for DNA detection.

    Science.gov (United States)

    Zhang, Yingwei; Luo, Yonglan; Tian, Jingqi; Asiri, Abdullah M; Al-Youbi, Abdulrahman O; Sun, Xuping

    2012-01-01

    In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs) assembled from Cu(II) and 4,4'-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1) RCPN binds dye-labeled single-stranded DNA (ssDNA) probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2) Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA) which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.

  10. Colorimetric and Fluorescent Dual Mode Sensing of Alcoholic Strength in Spirit Samples with Stimuli-Responsive Infinite Coordination Polymers.

    Science.gov (United States)

    Deng, Jingjing; Ma, Wenjie; Yu, Ping; Mao, Lanqun

    2015-07-07

    This study demonstrates a new strategy for colorimetric and fluorescent dual mode sensing of alcoholic strength (AS) in spirit samples based on stimuli-responsive infinite coordination polymers (ICPs). The ICP supramolecular network is prepared with 1,4-bis(imidazol-1-ylmethyl)benzene (bix) as the ligand and Zn(2+) as the central metal ion in ethanol, in which rhodamine B (RhB) is encapsulated through self-adaptive chemistry. In pure ethanol solvent, the as-formed RhB/Zn(bix) is well dispersed and quite stable. However, the addition of water into the ethanol dispersion of RhB/Zn(bix) destroys Zn(bix) network structure, resulting in the release of RhB from ICP into the solvent. As a consequence, the solvent displays the color of released RhB and, at the meantime, turns on the fluorescence of RhB, which constitutes a new mechanism for colorimetric and fluorescent dual mode sensing of AS in commercial spirit samples. With the method developed here, we could distinguish the AS of different commercial spirit samples by the naked eye within a wide linear range from 20 to 100% vol and by monitoring the increase of fluorescent intensity of the released RhB. This study not only offers a new method for on-spot visible detection of AS in commercial spirit samples, but also provides a strategy for designing dual mode sensing mechanisms for different analytical purposes based on novel stimuli-responsive materials.

  11. Photoinduced electron transfer fluorometric Hg(II) chemosensor based on a BODIPY armed with a tetrapod receptor.

    Science.gov (United States)

    Culzoni, M J; Muñoz de la Peña, A; Machuca, A; Goicoechea, H C; Brasca, R; Babiano, R

    2013-12-15

    From the great variety of BODIPY based-chemosensors able to determine Hg(2+), only a small portion has been applied to its determination in environmental and/or biological samples. The lack of studies on the analytical performance of the latter sensors makes interesting the development of investigations oriented to their possible analytical applications. The synthesis of a BODIPY derivative armed with a tetrapod receptor is described. The procedure is based on a previous publication, and the modifications performed to improve the synthesis include alternative procedures with different objectives, as the consecution of a multigram synthesis, improving the low yields of some of the previously proposed procedure steps, simplifying the experimental steps, achieving the desired purity requirements for use with analytical purposes, and enriching the characterization of the implied structures. The characteristics of its selectivity towards Hg(2+) have been investigated, and the OFF-ON fluorometric response, based on a photo-electron transfer (PET) mechanism, served as the base for the development of a method able to determine Hg(2+) in environmental waters at ng mL(-1) levels. The intrinsic fluorescence of the BODIPY core is inhibited and the probe exhibits a weak fluorescence (i.e. "OFF" state due to the deactivating PET effect). Upon complexation, Hg(2+) interacts with the lone-pair electrons on the nitrogen atoms of the receptor moiety so that the electronic transfer from the receptor to the photo-excited fluorophore is slowed down or switched off (i.e. "ON" state due to the suppression of the deactivating PET effect by coordination of the analyte to the probe). Regarding the complex photostability in aqueous solution, it is mandatory to conduct the experiments at darkness due to its photodegradation. The stoichiometry studies indicated a 1:2 relationship for the BODIPY-Hg(2+) complex. The high selectivity towards mercuric ions is considerably influenced by pH, being

  12. A Biphenol-Based Chemosensor for Zn(II) and Cd(II) Metal Ions: Synthesis, Potentiometric Studies, and Crystal Structures.

    Science.gov (United States)

    Ambrosi, Gianluca; Formica, Mauro; Fusi, Vieri; Giorgi, Luca; Macedi, Eleonora; Micheloni, Mauro; Paoli, Paola; Rossi, Patrizia

    2016-08-01

    We synthesized and characterized the ligand N,N'-bis[(2,2'-dihydroxybiphen-3-yl)methyl]-N,N'-dimethylethylenediamine (L), which contains two biphenol moieties linked as side arms to an N,N'-dimethylethylenediamine scaffold. The ligand is highly soluble in a 50/50 (v/v) water/ethanol mixture and, in its deprotonated form H-2L(2-), is able to coordinate transition-metal ions such as Ni(II), Zn(II), Cu(II), Cd(II), and Pd(II). The crystal structures of [Ni(H-2L)·2n-BuOH], [Ni(H-2L)·2MeOH], [Cd(H-2L)·2DMF], [Cu(H-2L)(DMF)], and [Pd(H-2L)(DMF)] were also determined and described. Potentiometric titrations were carried out in a mixed solvent with Zn(II), Cu(II), and Ni(II) metal ions to determine the acid-base and stability constants. L was highly fluorescent in the visible range (400 nm). Moreover, its emission intensity increased upon the addition of Zn(II) or Cd(II) ions in an ethanol/water solution and behaved as a chemosensor for the presence of these ions in the solution.

  13. Fe-nitrilotriacetic acid coordination polymer nanowires: an effective sensing platform for fluorescence-enhanced nucleic acid detection

    Science.gov (United States)

    Zhou, Yunchun; Liu, Qian; Sun, Xuping; Kong, Rongmei

    2017-02-01

    The determination of specific nucleic acid sequences is key in identifying disease-causing pathogens and genetic diseases. In this paper we report the utilization of Fe-nitrilotriacetic acid coordination polymer nanowires as an effective nanoquencher for fluorescence-enhanced nucleic acid detection. The detection is fast and the whole process can be completed within 15 min. This nanosensor shows a low detection limit of 0.2 nM with selectivity down to single-base mismatch. This work provides us with an attractive sensing platform for applications.

  14. Luminescent Metal Nanoclusters for Potential Chemosensor Applications

    Directory of Open Access Journals (Sweden)

    Muthaiah Shellaiah

    2017-12-01

    Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

  15. A napthelene-pyrazol conjugate: Al(III) ion-selective blue shifting chemosensor applicable as biomarker in aqueous solution.

    Science.gov (United States)

    Mukherjee, Manjira; Pal, Siddhartha; Lohar, Somenath; Sen, Buddhadeb; Sen, Supriti; Banerjee, Samya; Banerjee, Snehasis; Chattopadhyay, Pabitra

    2014-10-07

    A newly synthesized and crystalographically characterized napthelene–pyrazol conjugate, 1-[(5-phenyl-1H-pyrazole-3-ylimino)-methyl]-naphthalen-2-ol (HL) behaves as an Al(III) ion-selective chemosensor through internal charge transfer (ICT)-chelation-enhanced fluorescence (CHEF) processes in 100 mM HEPES buffer (water–DMSO 5:1, v/v) at biological pH with almost no interference of other competitive ions. This mechanism is readily studied from electronic, fluorimetric and (1)H NMR titration. The probe (HL) behaved as a highly selective fluorescent sensor for Al(III) ions as low as 31.78 nM within a very short response time (15–20 s). The sensor (HL), which has no cytotoxicity, is also efficient in detecting the distribution of Al(III) ions in HeLa cells via image development under fluorescence microscope.

  16. Tricolor emission of a fluorescent heteroditopic ligand over a concentration gradient of zinc(II) ions.

    Science.gov (United States)

    Sreenath, Kesavapillai; Clark, Ronald J; Zhu, Lei

    2012-09-21

    The internal charge transfer (ICT) type fluoroionophore arylvinyl-bipy (bipy = 2,2'-bipyridyl) is covalently tethered to the spirolactam form of rhodamine to afford fluorescent heteroditopic ligand 4. Compound 4 can be excited in the visible region, the emission of which undergoes sequential bathochromic shifts over an increasing concentration gradient of Zn(ClO(4))(2) in acetonitrile. Coordination of Zn(2+) stabilizes the ICT excited state of the arylvinyl-bipy component of 4, leading to the first emission color shift from blue to green. At sufficiently high concentrations of Zn(ClO(4))(2), the nonfluorescent spirolactam component of 4 is transformed to the fluorescent rhodamine, which turns the emission color from green to orange via intramolecular fluorescence resonance energy transfer (FRET) from the Zn(2+)-bound arylvinyl-bipy fluorophore to rhodamine. While this work offers a new design of ratiometric chemosensors, in which sequential analyte-induced emission band shifts result in the sampling of multiple colors at different concentration ranges (i.e., from blue to green to orange as [Zn(2+)] increases in the current case), it also reveals the nuances of rhodamine spirolactam chemistry that have not been sufficiently addressed in the published literature. These issues include the ability of rhodamine spirolactam as a fluorescence quencher via electron transfer, and the slow kinetics of spirolactam ring-opening effected by Zn(2+) coordination under pH neutral aqueous conditions.

  17. Fluorescence sensing of spermine with a frustrated amphiphile.

    Science.gov (United States)

    Köstereli, Ziya; Severin, Kay

    2012-06-14

    A charge-frustrated amphiphile composed of a pyrene-1,3,6-trisulfonate head group and an eicosane side chain can be used as a fluorescence chemosensor for spermine. The sensor allows the detection of spermine down to the nanomolar concentration range with good selectivity over closely related biogenic amines such as spermidine.

  18. Colorimetric assay for on-the-spot alcoholic strength sensing in spirit samples based on dual-responsive lanthanide coordination polymer particles with ratiometric fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jingjing, E-mail: jjdeng@des.ecnu.edu.cn [School of Ecological and Environmental Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); Shi, Guoyue [Department of Chemistry, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); Zhou, Tianshu, E-mail: tszhou@des.ecnu.edu.cn [School of Ecological and Environmental Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China)

    2016-10-26

    This study demonstrates a new strategy for colorimetric detection of alcoholic strength (AS) in spirit samples based on dual-responsive lanthanide infinite coordination polymer (Ln-ICP) particles with ratiometric fluorescence. The ICP used in this study are composed of two components: one is the supramolecular Ln-ICP network formed by the coordination between the ligand 2,2’-thiodiacetic acid (TDA) and central metal ion Eu{sup 3+}; and the other is a fluorescent dye, i.e., coumarin 343 (C343), both as the cofactor ligand and as the sensitizer, doped into the Ln-ICP network through self-adaptive chemistry. Upon being excited at 300 nm, the red fluorescence of Ln-ICP network itself at 617 nm is highly enhanced due to the concomitant energy transfer from C343 to Eu{sup 3+}, while the fluorescence of C343 at 495 nm is supressed. In pure ethanol solvent, the as-formed C343@Eu-TDA is well dispersed and quite stable. However, the addition of water into ethanolic dispersion of C343@Eu-TDA destructs Eu-TDA network structure, resulting in the release of C343 from ICP network into the solvent. Consequently, the fluorescence of Eu-TDA turns off and the fluorescence of C343 turns on, leading to the fluorescent color change of the dispersion from red to blue, which constitutes a new mechanism for colorimetric sensing of AS in commercial spirit samples. With the method developed here, we could clearly distinguish the AS of different spirit samples within a wide linear range from 10% vol to 100% vol directly by “naked eye” with the help of UV-lamp (365 nm). This study not only offers a new method for on-the-spot visible detection of AS, but also provides a strategy for dual-responsive sensing mode by rational designing the optical properties of the Ln-ICP network and the guest, respectively. - Highlights: • Dual responsive lanthanide coordination polymer particles C343@Eu-TDA were synthesized. • The guest molecular coumarin 343 sensitized the luminescence of Eu

  19. A supramolecular Tröger's base derived coordination zinc polymer for fluorescent sensing of phenolic-nitroaromatic explosives in water.

    Science.gov (United States)

    Shanmugaraju, Sankarasekaran; Dabadie, Charlyne; Byrne, Kevin; Savyasachi, Aramballi J; Umadevi, Deivasigamani; Schmitt, Wolfgang; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

    2017-02-01

    A V-Shaped 4-amino-1,8-napthalimide derived tetracarboxylic acid linker (L; bis-[N-(1,3-benzenedicarboxylic acid)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine) comprising the Tröger's base (TB) structural motif was rationally designed and synthesised to access a nitrogen-rich fluorescent supramolecular coordination polymer. By adopting the straight forward precipitation method, a new luminescent nanoscale Zn(ii) coordination polymer (TB-Zn-CP) was synthesized in quantitative yield using Zn(OAc)2·2H2O and tetraacid linker L (1 : 0.5) in DMF at room temperature. The phase-purity of as-synthesised TB-Zn-CP was confirmed by X-ray powder diffraction analysis, infra-red spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that TB-Zn-CP is thermally stable up to 330 °C and the morphological features of TB-Zn-CP was analysed by SEM and AFM techniques. The N2 adsorption isotherm of thermally activated TB-Zn-CP at 77 K revealed a type-II reversible adsorption isotherm and the calculated Brunauer-Emmett-Teller (BET) surface area was found to be 72 m2 g-1. Furthermore, TB-Zn-CP displayed an excellent CO2 uptake capacity of 76 mg g-1 at 273 K and good adsorption selectivity for CO2 over N2 and H2. The aqueous suspension of as-synthesized TB-Zn-CP showed strong green fluorescence (λmax = 520 nm) characteristics due to the internal-charge transfer (ICT) transition and was used as a fluorescent sensor for the discriminative sensing of nitroaromatic explosives. The aqueous suspension of TB-Zn-CP showed the largest quenching responses with high selectivity for phenolic-nitroaromatics (4-NP, 2,4-DNP and PA) even in the concurrent presence of other potentially competing nitroaromatic analytes. The fluorescence titration studies also provide evidence that TB-Zn-CP detects picric acid as low as the parts per billion (26.3 ppb) range. Furthermore, the observed fluorescence quenching responses of TB-Zn-CP towards picric acid were highly reversible. The

  20. A turn-on fluorescent sensor for detection of cyanide in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shan-Teng; Chir, Jiun-Ly; Jhong, Yi; Wu, An-Tai, E-mail: antai@cc.ncue.edu.tw

    2015-11-15

    2-Hydroxy-1-naphthaldehyde oxime (receptor 1) serves as a selective chemosensor for cyanide anion (CN{sup −}). In the presence of CN{sup −}, an enhanced fluorescent intensity and red-shift were observed. The observed complexation between receptor 1 and CN{sup −} may cause by a hydrogen bonding interaction between the OH group of receptor 1 and CN{sup −}. - Highlights: • 2-Hydroxy-1-naphthaldehyde oxime serves as a selective chemosensor for CN{sup −}. • In the presence of CN{sup −}, an enhanced fluorescent and red-shift were observed.

  1. Development of chemosensor for Sr(2+) using organic nanoparticles: application of sensor in product analysis for oral care.

    Science.gov (United States)

    Kaur, Simanpreet; Kaur, Amanpreet; Kaur, Navneet; Singh, Narinder

    2014-11-07

    A new series of compounds has been developed for the recognition of metal ions and it was found that the position of substituent in the organic compound proved to be the deciding factor for the development of a chemosensor. Reprecipitation method was used to develop organic nanoparticles (ONPs) in aqueous medium and the suspension of ONP in aqueous medium remained stable for one month. These ONPs were studied for their recognition abilities using fluorescence spectroscopy and only ONPs of compound 1 resulted in a sensor for Sr(2+) and the sensor activities were found to be unaffected by the presence of any other cation. The sensor was successfully used to investigate the level of Sr(2+) in an oral gel, as well as toothpastes used to cure sensitive teeth.

  2. An integrated logic system for time-resolved fluorescent "turn-on" detection of cysteine and histidine base on terbium (III) coordination polymer-copper (II) ensemble.

    Science.gov (United States)

    Xue, Shi-Fan; Lu, Ling-Fei; Wang, Qi-Xian; Zhang, Shengqiang; Zhang, Min; Shi, Guoyue

    2016-09-01

    Cysteine (Cys) and histidine (His) both play indispensable roles in many important biological activities. An enhanced Cys level can result in Alzheimer's and cardiovascular diseases. Likewise, His plays a significant role in the growth and repair of tissues as well as in controlling the transmission of metal elements in biological bases. Therefore, it is meaningful to detect Cys and His simultaneously. In this work, a novel terbium (III) coordination polymer-Cu (II) ensemble (Tb(3+)/GMP-Cu(2+)) was proposed. Guanosine monophosphate (GMP) can self-assemble with Tb(3+) to form a supramolecular Tb(3+) coordination polymer (Tb(3+)/GMP), which can be suited as a time-resolved probe. The fluorescence of Tb(3+)/GMP would be quenched upon the addition of Cu(2+), and then the fluorescence of the as-prepared Tb(3+)/GMP-Cu(2+) ensemble would be restored again in the presence of Cys or His. By incorporating N-Ethylmaleimide and Ni(2+) as masking agents, Tb(3+)/GMP-Cu(2+) was further exploited as an integrated logic system and a specific time-resolved fluorescent "turn-on" assay for simultaneously sensing His and Cys was designed. Meanwhile it can also be used in plasma samples, showing great potential to meet the need of practical application. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Fluorescence behavior of glutathione capped CdTe@ZnS quantum dots chemically coordinated to zinc octacarboxy phthalocyanines

    Energy Technology Data Exchange (ETDEWEB)

    Sekhosana, Kutloano E.; Antunes, Edith; Khene, Samson; D’Souza, Sarah [Department of Chemistry, Rhodes University, Grahamstown (South Africa); Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za [Department of Chemistry, Rhodes University, Grahamstown (South Africa)

    2013-04-15

    Core–shell CdTe@ZnS quantum dots capped with glutathione (CdTe@ZnS–GSH) were covalently linked to zinc octacarboxy phthalocyanine (ZnPc(COOH){sub 8}). The conjugate was characterized by UV/Vis, infrared and X-Ray photoelectron spectroscopies as well as transmission electron and atomic force microscopies. The fluorescence quantum yields of the core CdTe capped with thioglycolic acid increased upon formation of the core-shell. Upon conjugation with ZnPc(COOH){sub 8}, the fluorescence quantum yield of CdTe@ZnS–GSH decreased due to energy transfer from the latter to the Pc. The average fluorescence lifetime of the CdTe@ZnS–GSH QD also decreased upon conjugation from 26.2 to 13.3 ns. -- Graphical Abstract: CdTe@ZnS quantum dots capped with glutathione (CdTe@ZnS-GSH) and covalently linked to zinc octacarboxy phthalocyanine (ZnPc(COOH)8), showed decreased fluorescence quantum yield and lifetime of the CdTe@ZnS-GSH following conjugation due to energy transfer. Highlights: ► CdTe@ZnS quantum dots capped with glutathione were synthesized. ► The quantum dots were chemically linked to zinc octacarboxy phthalocyanine. ► The fluorescence quantum yields of the quantum dots decreased on conjugation. ► Fluorescence lifetimes also decreased due to energy transfer.

  4. Sonochemical synthesis and characterization of a new nano Ce(III) coordination supramolecular compound; highly sensitive direct fluorescent sensor for Cu2.

    Science.gov (United States)

    Geranmayeh, Shokoofeh; Mohammadnejad, Masoumeh; Mohammadi, Samaneh

    2018-01-01

    Micro and nano-structures of a new Ce(III) Coordination supramolecular compound, [Ce (1,5-NDS)1.5(H2O)5]n,1, (1,5-Naphthalenedisulfonic acid), were prepared using hydrothermal and sonochemical approaches, respectively. These new micro and nano structures were characterized by elemental analysis, IR spectra, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X-ray diffraction. The X-ray single crystal structure determination of 1 shows that it features a neutral 2D framework based on the [Ce2H20O16S2] clusters as a secondary building unit (SBU) which shows a sql/Shubnikov tetragonal plane net. Moreover by considering the H-bonds, the final structure can be considered as 3D supramolecular network. The influence of ultrasound irradiation time on the morphology and size of the nanostructure 1 was investigated. The results indicated that by increasing the time of ultrasonic radiation, smaller nanostructures form and morphological changes occur. Fluorescent properties of the nanoparticles of 1 were also investigated. Coordination polymer 1 shows high fluorescence intensity and good tendency to copper ion that can be used as an optical sensor for selective and sensitive determination of Cu2+ in aqueous media with detection limit of 3.0μM. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    Science.gov (United States)

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems.

  6. Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

    OpenAIRE

    Malanga, Milo; B?lint, Mih?ly; Pusk?s, Istv?n; Tuza, Kata; Sohajda, Tam?s; Jicsinszky, L?szl?; Szente, Lajos; Fenyvesi, ?va

    2014-01-01

    Summary The fluorescent tagging of cyclodextrin derivatives enlarges their spectroscopic properties thus generating chemosensors, biological tools for visualization and sophisticated photoresponsive devices. Cyclodextrin polymers, due to the cooperative interactions, exhibit additional properties compared to their monomeric counterpart. These macromolecules can be prepared either in well water-soluble form or as gels of high swelling. Two versatile synthetic strategies for introducing a fluor...

  7. Light and colour as analytical detection tools: a journey into the periodic table using polyamines to bio-inspired systems as chemosensors.

    Science.gov (United States)

    Lodeiro, Carlos; Capelo, José Luis; Mejuto, Juan Carlos; Oliveira, Elisabete; Santos, Hugo M; Pedras, Bruno; Nuñez, Cristina

    2010-08-01

    This critical review describes some developments on the chemistry of fluorescent and colorimetric molecular probes or chemosensors, based on polyamines and associated compounds having oxygen and/or sulfur as donor atoms. The reported systems are essentially based on some selected published work in this field in the last five years, and in the work developed by the authors from 2000 onwards. Some interesting properties beyond sensing molecules, ions or/and cations by fluorescence, colorimetry as well as by MALDI-TOF MS spectrometry can arise from these systems. A short brief on different examples activated by PET (photoinduced electron transfer), ICT (internal charge transfer) and EET (electronic energy transfer) phenomena will be provided. Finally the introduction of bio-inspired compounds derived from emissive amino acid or short peptide systems and nanoparticle devices to detect metal ions will be reviewed (202 references).

  8. A Reversible Pyrene-based Turn-on Luminescent Chemosensor for Selective Detection of Fe(3+) in Aqueous Environment with Logic Gate Application.

    Science.gov (United States)

    Mukherjee, Soma; Talukder, Shrabani

    2016-05-01

    A new Schiff-base, HL luminescent chemosensor of 1-amino pyrene and 8-hydroxy quinoline-2-carboxaldehyde was synthesized which demonstrates selective fluorimetric detection of Fe(3+) in aqueous medium with detection limit of 2.52 × 10(-8) M. The receptor shows selective 'turn-on' response towards Fe(3+) over other metal ions. This gradual 'turn-on' fluorescence response for Fe(3+) may be induced via CHEF (chelation-enhanced fluorescence) through close proximity of pyrene rings. The stoichiometry and binding property of HL with Fe(3+) was examined by emission studies. In presence of Fe(3+), HL also exhibits reversible change in emission pattern with EDTA and thus offers an interesting property of molecular 'INHIBIT' logic gate with Fe(3+) and EDTA as chemical inputs.

  9. Structural diversity and fluorescence properties of three 2-sulfoterephthalate Cd{sup II}/Zn{sup II} coordination polymers employing 1,4-bisbenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yixia, E-mail: renyixia1@163.com; Chai, Hongmei; Tang, Long; Hou, Xiangyang; Wang, Jijiang

    2016-02-15

    Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H{sub 2}O){sub 2}]·3H{sub 2}O (1), [Cd{sub 1.5}(2-stp)(1,4-bbi)(H{sub 2}O){sub 2}]·H{sub 2}O (2) and [Zn{sub 2}(2-stp)(μ{sub 2}-OH)(1,4-bbi){sub 1.5}(H{sub 2}O)]·6H{sub 2}O (3) (2-H{sub 3}stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on the formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π* transition, which means they could be potential fluorescence materials. - Graphical abstract: Three new Cd{sup II}/Zn{sup II} 2-sulfoterephthalate (2-H{sub 3}stp) complexes with 1,4-bisbenzimidazole (1,4-bbi) are described. Complex 1 exhibits one-dimensional chain-like structure, 2 is a three-dimensional bbi-pillared wavy-like layer framework, while 3 is a three-dimensional stp-pillared layer architecture. Fluorescence spectra exhibit the π–π* transition of two organic ligands. - Highlights: • Three Cd{sup II}/Mn{sup II} 2-sulfoterephthalate complexes containing 1,4-bisbenzimidazole. • Different structural features despite the same raw materials for 1 and 2. • Fluorescence spectra exhibit the π–π* transition of organic ligands.

  10. Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging

    Science.gov (United States)

    Warrier, Sona; Kharkar, Prashant S.

    2018-01-01

    A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe3+ ions. Probe 1 exhibited high fluorescence emission profile at 447 nm, excellent selectivity towards Fe3+ over other biologically important metal ions (Al3+, Ba2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Sn2+). Interestingly, there was 30-fold decrease in fluorescence intensity upon Fe3+ binding. The limit of detection of Fe3+ was found to be 0.76 μM ( 40 ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe3+.

  11. A cost-effective and practical polybenzanthrone-based fluorescent sensor for efficient determination of palladium (II) ion and its application in agricultural crops and environment.

    Science.gov (United States)

    Zhang, Ge; Wen, Yangping; Guo, Chaoqun; Xu, Jingkun; Lu, Baoyang; Duan, Xuemin; He, Haohua; Yang, Jun

    2013-12-17

    A highly selective and sensitive fluorescent chemosensor suitable for practical measurement of palladium ion (Pd(2+)) in agricultural crops and environment samples has been successfully fabricated using polybenzanthrone (PBA). PBA was facilely electrosynthesized in the mixed electrolyte of acetonitrile and boron trifluoride diethyl etherate. The fluorescence intensity of PBA showed a linear response to Pd(2+) in the concentration range of 5 nM-0.12 mM with a detection limit of 0.277 nM and quantification limit of 0.925 nM. Different compounds existing in agricultural crops and environment such as common metal ions, anions, natural amino acids, carbohydrates, and organic acids were used to examine the selectivity of the as-fabricated sensor, and no obvious fluorescence change could be observed in these interferents and their mixtures. A possible mechanism was proposed that the coordination of PBA and Pd(2+) enhance the aggregation of polymer chains, which led to a significant quenching of PBA emission, and this was further confirmed by absorption spectra monitoring and transmission electron microscopy. The excellent performance of the proposed sensor and satisfactory results of the Pd(2+) determination in practical samples suggested that the PBA-based fluorescent sensor for the determination of Pd(2+) will be a good candidate for application in agriculture and environment. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Solid-phase synthesis of highly fluorescent nitrogen-doped carbon dots for sensitive and selective probing ferric ions in living cells.

    Science.gov (United States)

    Zhang, Haijuan; Chen, Yonglei; Liang, Meijuan; Xu, Laifang; Qi, Shengda; Chen, Hongli; Chen, Xingguo

    2014-10-07

    Carbon quantum dots (C-Dots) have drawn extensive attention in recent years due to their stable physicochemical and photochemical properties. However, the development of nitrogen-doped carbon quantum dots (N-doped C-Dots) is still on its early stage. In this paper, a facile and high-output solid-phase synthesis approach was proposed for the fabrication of N-doped, highly fluorescent carbon quantum dots. The obtained N-doped C-Dots exhibited a strong blue emission with an absolute quantum yield (QY) of up to 31%, owing to fluorescence enhancement effect of introduced N atoms into carbon dots. The strong coordination of oxygen-rich groups on N-doped C-Dots to Fe(3+) caused fluorescence quenching via nonradiative electron-transfer, leading to the quantitative detection of Fe(3+). The probe exhibited a wide linear response concentration range (0.01-500 μM) to Fe(3+) with a detection limit of 2.5 nM. Significantly, the N-doped C-Dots possess negligible cytotoxicity, excellent biocompatibility, and high photostability. All these features are favorable for label-free monitoring of Fe(3+) in complex biological samples. It was then successfully applied for the fluorescence imaging of intracellular Fe(3+). As an efficient chemosensor, the N-doped C-Dots hold great promise to broaden applications in biological systems.

  13. Four thiophene-pyridyl-amide-based Zn{sup II}/Cd{sup II} coordination polymers: Assembly, structures, photocatalytic properties and fluorescent recognition for Fe{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiu-Li; Wu, Xiao-Mei; Liu, Guo-Cheng; Li, Qiao-Min; Lin, Hong-Yan; Wang, Xiang

    2017-05-15

    By tuning metal ions and combining with different dicarboxylates, four new semi-rigid thiophene-bis-pyridyl-bis-amide-based coordination polymers, namely, [Zn(3-bptpa)(1,3-BDC)]·DMA·2H{sub 2}O (1), [Zn(3-bptpa)(5-MIP)] (2), [Cd(3-bptpa)(1,3-BDC)]·2H{sub 2}O (3) and [Cd(3-bptpa)(5-MIP)]·4H{sub 2}O (4) (3-bptpa=N,N′-bis(pyridine-3-yl)thiophene-2,5-dicarboxamide, 1,3-H{sub 2}BDC=1,3-benzenedicarboxylic acid, 5-H{sub 2}MIP=5-methylisophthalic acid, DMA=N,N-dimethylacetamide), were solvothermally/hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analyses, IR spectra, UV–vis diffuse-reflectance spectra (DRS), powder X-ray diffraction (PXRD) and thermal gravimetric analyses (TG). The structural analysis reveals that Zn-complexes 1 and 2 are similar 2D networks. While Cd-complexes 3 and 4 exhibit similar 2-fold interpenetrating 3D α-Po frameworks with the (4{sup 12}·6{sup 3}) topology. The photocatalytic properties for the degradation of methylene blue (MB) under ultraviolet light irradiation of the title complexes have been investigated in detail. Furthermore, the luminescent sensing behaviors for metal cations of 1–4 have been studied, the results indicate that 3 is an excellent fluorescent probe, with high sensitivity, selectivity, and simple regeneration, for environmentally relevant Fe{sup 3+} ions. - Graphical abstract: Four Zn{sup II}/Cd{sup II} coordination polymers with a thiophene-pyridyl-amide ligand have been prepared. The photocatalytic activities and fluorescent sensing properties for metal ions of the title complexes have been investigated. - Highlights: • Four coordination polymers with thiophene-pyridyl-amide ligands have been obtained. • The central metal ions play an important role in the formation of the frameworks. • The photoluminescent sensing and the photocatalytic properties have been investigated.

  14. A simple but efficient strategy to enhance hydrostability of intensely fluorescent Mg-based coordination polymer (CP) via forming a composite of CP with hydrophobic PVDF.

    Science.gov (United States)

    Zhai, Lu; Zhang, Wen-Wei; Zuo, Jing-Lin; Ren, Xiao-Ming

    2016-02-28

    A coordination polymer (CP) of Mg(2+) with 1,3,5-benzenetricarboxylate (BTC(3-)) was synthesized using a solvothermal method. The Mg-CP, with a formula of Mg3(BTC)(HCOO)3(DMF)3, crystallizes in the trigonal space group P3[combining macron], with cell parameters of a = b = 13.972(5) Å, c = 8.090(5) Å and V = 1367.6(11) Å(3), and shows a lamella structure built from planar rosette-type hexanuclear architectures. The Mg-CP emits intense blue fluorescence arising from π* → π transition of intra-ligand of BTC(3-) with 21.69% quantum yield, yet it exhibits poor stability to water. The composites of Mg-CP with hydrophobic polyvinylidene fluoride (PVDF) were sequentially prepared by mechanically mixed, tableted and annealed processes, which showed good compatibility between Mg-CP and PVDF, high hydrostability, and intense blue emission. This study suggests a simple but efficient method to solve the drawbacks of some functional CPs unstable to water and to promote them as practical applications in the field of functional materials.

  15. Four thiophene-pyridyl-amide-based ZnII/CdII coordination polymers: Assembly, structures, photocatalytic properties and fluorescent recognition for Fe3+

    Science.gov (United States)

    Wang, Xiu-Li; Wu, Xiao-Mei; Liu, Guo-Cheng; Li, Qiao-Min; Lin, Hong-Yan; Wang, Xiang

    2017-05-01

    By tuning metal ions and combining with different dicarboxylates, four new semi-rigid thiophene-bis-pyridyl-bis-amide-based coordination polymers, namely, [Zn(3-bptpa)(1,3-BDC)]·DMA·2H2O (1), [Zn(3-bptpa)(5-MIP)] (2), [Cd(3-bptpa)(1,3-BDC)]·2H2O (3) and [Cd(3-bptpa)(5-MIP)]·4H2O (4) (3-bptpa=N,N‧-bis(pyridine-3-yl)thiophene-2,5-dicarboxamide, 1,3-H2BDC=1,3-benzenedicarboxylic acid, 5-H2MIP=5-methylisophthalic acid, DMA=N,N-dimethylacetamide), were solvothermally/hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analyses, IR spectra, UV-vis diffuse-reflectance spectra (DRS), powder X-ray diffraction (PXRD) and thermal gravimetric analyses (TG). The structural analysis reveals that Zn-complexes 1 and 2 are similar 2D networks. While Cd-complexes 3 and 4 exhibit similar 2-fold interpenetrating 3D α-Po frameworks with the (412·63) topology. The photocatalytic properties for the degradation of methylene blue (MB) under ultraviolet light irradiation of the title complexes have been investigated in detail. Furthermore, the luminescent sensing behaviors for metal cations of 1-4 have been studied, the results indicate that 3 is an excellent fluorescent probe, with high sensitivity, selectivity, and simple regeneration, for environmentally relevant Fe3+ ions.

  16. "Naked-eye" screening of metal-based chemosensors for biologically important anions.

    Science.gov (United States)

    Männel-Croisé, Christine; Meister, Christian; Zelder, Felix

    2010-11-15

    A two-step "naked-eye" screening of selective metal-based chemosensors for biologically important anions such as cyanide, phosphate, and oxalate from commercially available metal indicators and metal ions has been developed. Applications in food safety control have been demonstrated.

  17. Highly sensitive optical chemosensor for the detection of Cu 2 using ...

    Indian Academy of Sciences (India)

    ... a terdentate O2N binding unit into one molecule. The chemosensor RHN showed not only a reversible, selective, and sensitive absorbance enhancement response to Cu2+, but also a strong colour development against the colourless blank during the sensing event, a feature that would facilitate `naked-eye' detection.

  18. Selective detection of Cu2 + and Co2 + in aqueous media: Asymmetric chemosensors, crystal structure and spectroscopic studies

    Science.gov (United States)

    Dogaheh, Samira Gholizadeh; Khanmohammadi, Hamid; Carolina Sañudo, E.

    2017-05-01

    Two new azo-azomethine receptors, H2L1 and H2L2, containing hydrazine, naphthalene and different electron withdrawing groups, Cl and NO2, have been designed and synthesized for qualitative and quantitative detection of Cu2 + and Co2 + in aqueous media. The crystal structure of H2L1is reported. The H2L1was used as a chemosensor for selective detection of trace amount of Cu2 + in aqueous media. H2L2 was also applied to naked-eye distinction of Cu2 + and Co2 + from other transition metal ions in aqueous media. Detection limit of Cu2 + is 1.13 μM and 1.26 μM, in water, for H2L1 and H2L2, respectively, which are lower than the World Health Organization (WHO) recommended level. The binuclear Cu2 + and Co2 + complexes of the receptors have been also prepared and characterized using spectroscopic methods and MALDI-TOF mass analysis. Furthermore, the binding stoichiometry between the receptors upon the addition Cu2 + and Co2 + has been investigated using Job's plot. Moreover, the fluorescence emission spectra of the receptors and their metal complexes are also reported.

  19. Analytical assays based on chromogenic and fluorogenic chemosensors for the detection of cyanide

    Directory of Open Access Journals (Sweden)

    Vanderléia Gava Marini

    2010-06-01

    Full Text Available Cyanide (CN– is an anion well–known for its toxicity, being a chemical agent often related to cases of homicide and suicide. Despite being responsible for the toxicity of many animals and plants, it is used in several industrial activities, with innumerous implications in terms of the environment. Due to its high toxicity, the maximum level of CN– concentration allowed by the World Health Organization in potable water is 1.7 µmol/L. This low concentration limit requires methods of visual detection and quantitative determination which are ever more sensitive, simple, reliable, and economical. Advancements in the field of chromogenic and fluorogenic chemosensors for anionic analytes have led to the development of several methodologies for the detection of CN–. Therefore, this review aims to present the main strategies that have been used in the study of quantitative and naked–eye detection of CN– by means of chromogenic and fluorogenic chemosensors. Aspects related to CN–, such as its reactivity, toxicity, applications, and implications in different domains of knowledge, are presented. Recent work involving the development of chemosensors for CN– based on acid–base reactions, chemodosimeters, chromoreactands, and competition assays is also described. In addition, recent studies that make use of nanotechnology to develop strategies for the detection of CN– are also discussed, as well as the prospects envisioned in this field.

  20. Synthesis of New Blue Fluorescent Polymerizable 1,8-Naphthalimides and Their Copolymers with Styrene as Sensors for Fe(III Cations

    Directory of Open Access Journals (Sweden)

    Ivo Grabchev

    2014-01-01

    Full Text Available The synthesis, characterization, and functional properties of two new polymerizable 1,8-naphthalimides (MDs have been described. Their copolymers with styrene designed to act as a fluorescence PET chemosensor have been investigated. The study also reports the influence of different metal cations (Ag+, Mg2+, Cu2+, Sr2+, Co2+, Pb2+, and Fe3+ on the fluorescence intensity of both low and high molecular weight fluorophores.

  1. Efficient one-pot synthesis of hydrophilic and fluorescent molecularly imprinted polymer nanoparticles for direct drug quantification in real biological samples.

    Science.gov (United States)

    Niu, Hui; Yang, Yaqiong; Zhang, Huiqi

    2015-12-15

    Efficient one-pot synthesis of hydrophilic and fluorescent molecularly imprinted polymer (MIP) nanoparticles and their application as optical chemosensor for direct drug quantification in real, undiluted biological samples are described. The general principle was demonstrated by preparing tetracycline (Tc, a broad-spectrum antibiotic)-imprinted fluorescent polymer nanoparticles bearing hydrophilic polymer brushes via poly(2-hydroxyethyl methacrylate) (PHEMA) macromolecular chain transfer agent-mediated reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization in the presence of a fluorescent monomer. The introduction of hydrophilic PHEMA brushes and fluorescence labeling onto/into the MIP nanoparticles proved to not only significantly improve their surface hydrophilicity and lead to their obvious specific binding and high selectivity toward Tc in the undiluted bovine serum, but also impart them with strong fluorescent properties. In particular, significant fluorescence quenching was observed upon their binding with Tc in such complex biological milieu, which makes these Tc-MIP nanoparticles useful optical chemosensor with a detection limit of 0.26 μM. Furthermore, such advanced functional MIP nanoparticles-based chemosensor was also successfully utilized for the direct, sensitive, and accurate determination of Tc in another biological medium (i.e., the undiluted pig serum) with average recoveries ranging from 98% to 102%, even in the presence of several interfering drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Cyclodextrin-Based Metal-Organic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H2S-Involved Coordination Mechanism

    Science.gov (United States)

    Xin, Xuelian; Wang, Jingxin; Gong, Chuanfang; Xu, Hai; Wang, Rongming; Ji, Shijie; Dong, Hanxiao; Meng, Qingguo; Zhang, Liangliang; Dai, Fangna; Sun, Daofeng

    2016-02-01

    Hydrogen sulfide (H2S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H2S in living cells is very important to human health because it has been found that the abnormal levels of H2S in human body can cause Alzheimer’s disease, cancers and diabetes. Herein, we develop a cyclodextrin-based metal-organic nanotube, CD-MONT-2, possessing a {Pb14} metallamacrocycle for efficient detection of H2S. CD-MONT-2‧ (the guest-free form of CD-MONT-2) exhibits turn-on detection of H2S with high selectivity and moderate sensitivity when the material was dissolved in DMSO solution. Significantly, CD-MONT-2‧ can act as a fluorescent turn-on probe for highly selective detection of H2S in living cells. The sensing mechanism in the present work is based on the coordination of H2S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.

  3. Advances in Biosensors, Chemosensors and Assays for the Determination of Fusarium Mycotoxins

    Directory of Open Access Journals (Sweden)

    Xialu Lin

    2016-05-01

    Full Text Available The contaminations of Fusarium mycotoxins in grains and related products, and the exposure in human body are considerable concerns in food safety and human health worldwide. The common Fusarium mycotoxins include fumonisins, T-2 toxin, deoxynivalenol and zearalenone. For this reason, simple, fast and sensitive analytical techniques are particularly important for the screening and determination of Fusarium mycotoxins. In this review, we outlined the related advances in biosensors, chemosensors and assays based on the classical and novel recognition elements such as antibodies, aptamers and molecularly imprinted polymers. Application to food/feed commodities, limit and time of detection were also discussed.

  4. A Turn-on and Reversible Fluorescence Sensor for Zinc Ion Based on 4,5-Diazafluorene Schiff Base.

    Science.gov (United States)

    Li, Hui; Zhang, ShuJiang; Gong, ChenLiang; Wang, JianZhi; Wang, Feng

    2016-09-01

    A new 4,5-diazafluorene-based fluorescent chemosensor has been synthesized by Schiff base condensation of 9,9-bis(3,5-dimethyl-4-aminophenyl)-4,5-diazafluorene with salicylaldehyde. The interaction of Schiff base with different metal ions has been studied over photofluorescent spectra. The results showed that Schiff base exhibited 194-fold enhancements in fluorescence at 465 nm after Zn(2+) ions. Such fluorescent responses could be detected by naked eye under UV-lamp. The complex solution (L-Zn(2+)) exhibited reversibility with EDTA.

  5. Selective chemosensor for Hg(II) ions based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene in aqueous samples

    NARCIS (Netherlands)

    Nuriman, [Unknown; Kuswandi, Bambang; Verboom, Willem

    2009-01-01

    A novel chemosensor, based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene (TPPECTV) as chromophore, has been developed for the colorimetric determination and visual detection of Hg(II) ions. TPPECTV exhibits a pronounced chromogenic behavior toward Hg(II) ions by changing the

  6. Three coordination polymers based on 9,10-di(pyridine-4-yl)anthracene ligand: Syntheses, structures and fluorescent properties

    Science.gov (United States)

    Dong, Jun-Liang; Wang, Duo-Zhi; Jia, Yan-Yuan; Wang, Dan-Hong

    2017-08-01

    Three new mixed-ligand divalent coordination polymers (CPs) {[Zn3(L)(1,4-bdc)3]·2DMF}n (1), {[Zn2(L)(2,6-ndc)2]·3DMF}n (2) and {[Cd2(L)3(2,6-ndc)2]}n (3) [L = 9,10-di(pyridine-4-yl)anthracene, 1,4-H2bdc = 1,4-benzenedicarboxylic acid, 2,6-H2ndc = 2,6-naphthalenedicarboxylic acid] have been prepared and well characterized by elemental analyses, infrared spectroscopy, single-crystal X-ray diffraction techniques, powder X-ray diffraction patterns and thermogravimetric analyses. The crystal structure analyses of coordination polymers (CPs) reveal that all the complexes 1-3 have the three-dimensional (3D) coordination networks. The structure of 1 can be simplified as a sqc3 3D 8-connected framework with the point symbol of (424·64). Particularly, in the presence of the linear 2,6-H2ndc auxiliary ligand, a double-deck interpenetrating pcu 3D network of 2 is assembled by 6-connecting framework with the point symbol of (412·63). Complex 3 exhibits a ttd 3D 5-connected net with a point symbol of (46·64). Further, the solid-state luminescent properties of the complexes 1-3 were measured and studied at room temperature.

  7. Highly Sensitive Fluorescence Probe Based on Functional SBA-15 for Selective Detection of Hg2+

    Directory of Open Access Journals (Sweden)

    Wang Xiaoyu

    2010-01-01

    Full Text Available Abstract An inorganic–organic hybrid fluorescence chemosensor (DA/SBA-15 was prepared by covalent immobilization of a dansylamide derivative into the channels of mesoporous silica material SBA-15 via (3-aminopropyltriethoxysilane (APTES groups. The primary hexagonally ordered mesoporous structure of SBA-15 was preserved after the grafting procedure. Fluorescence characterization shows that the obtained inorganic–organic hybrid composite is highly selective and sensitive to Hg2+ detection, suggesting the possibility for real-time qualitative or quantitative detection of Hg2+ and the convenience for potential application in toxicology and environmental science.

  8. Label-free fluorescent enzymatic assay of citrate synthase by CoA-Au(I) co-ordination polymer and its application in a multi-enzyme logic gate cascade.

    Science.gov (United States)

    Li, Yong; Wang, Huixia; Dai, Futao; Li, Pei; Jin, Xin; Huang, Yan; Nie, Zhou; Yao, Shouzhuo

    2016-12-15

    Citrate synthase (CS) is one of the key metabolic enzymes in the Krebs tricarboxylic acid (TCA) cycle. It regulates energy generation in mitochondrial respiration by catalysing the reaction between oxaloacetic acid (OAA) and acetyl coenzyme A (Ac-CoA) to generate citrate and coenzyme A (CoA). CS has been shown to be a biomarker of neurological diseases and various kinds of cancers. Here, a label-free fluorescent assay has been developed for homogeneously detecting CS and its inhibitor based on the in situ generation of CoA-Au(I) co-ordination polymer (CP) and the fluorescence signal-on by SYBR Green II-stained CoA-Au(I) CP. Because of the unique property of the CoA-Au(I) CP, this CS activity assay method could achieve excellent selectivity and sensitivity, with a linear range from 0.0033 U/μL to 0.264 U/μL and a limit of detection to be 0.00165 U/μL. Meanwhile, this assay method has advantages of being facile and cost effective with quick detection. Moreover, based on this method, a biomimetic logic system was established by rationally exploiting the cascade enzymatic interactions in TCA cycle for chemical information processing. In the TCA cycle-derived logic system, an AND-AND-AND-cascaded gate was rigorously operated step by step in one pot, and is outputted by a label-free fluorescent signal with visualized readout. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Crystal structures, fluorescent and magnetic properties of five new coordination polymers based on biphenyl-3,4 Prime ,5-tricarboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yingli [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Zhao Wenjie [Department of Biochemical Engineering, Xianyang Vocational Technical College, Xianyang 712000 (China); Liu Yu; Liu Bin; Feng Xing; Tan Jinting; Li Xia [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Yang Xuwu, E-mail: yangxuwu@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China)

    2012-08-15

    Five new coordination polymers, {l_brace}[Cd{sub 3}(bpt){sub 2}(DMF){sub 2}]{center_dot}(H{sub 2}O){sub 2}{r_brace}{sub n} (1), [Cd(Hbpt)(bipy){sub 0.5}(H{sub 2}O)]{sub n} (2), [Cd{sub 2}(bpt)(phen){sub 2}Cl]{sub n} (3), {l_brace}[Cu{sub 2}(bpt)(phen)({mu}{sub 2}-OH)(H{sub 2}O)]{center_dot}(H{sub 2}O){sub 2}{r_brace}{sub n} (4) and {l_brace}[Mn{sub 5}(Hbpt){sub 4}(phen){sub 4}({mu}{sub 2}-OH){sub 2}(H{sub 2}O){sub 2}]{center_dot}(H{sub 2}O){sub 2}(CH{sub 3}CN){sub 2}{r_brace}{sub n} (5) have been prepared through hydro(solvo)thermal reactions of H{sub 3}bpt (H{sub 3}bpt=biphenyl-3,4 Prime ,5-tricarboxylic acid) with different pyridyl-containing auxiliary ligands (bipy=4,4 Prime -bipyridine and phen=1,10-phenanthroline). Compound 1 represents a 3D ladder-like framework composed of rod-shaped infinite chains. In 2, the bridging ligand bipy links binuclear cadmium ions to generate a 2D layer. Compound 3 features a 1D ladder structure and further linked by {pi}-{pi} stacking interaction to form a 3D supramolecular network. Compound 4 exhibits a binodal 3-connected net which features the Schlafli symbol of (4{center_dot}8{sup 2}). Compound 5 contains trimetallic cluster and binuclear unite which are further linked by Hbpt ligand to form a 2D layer. Moreover, photoluminescent properties of compounds 1-3 were studied in the solid state. Magnetic susceptibility measurements indicate that compound 4 exhibits ferromagnetic exchange interactions, whereas compound 5 displays antiferromagnetic exchange interactions. - Graphical abstract: Five new coordination polymers have been prepared through reactions of H{sub 3}bpt with different pyridyl-containing auxiliary ligands. The bpt exhibits four new kinds of coordination modes with 'V or Y shape'. Highlights: Black-Right-Pointing-Pointer 1 represents a unique (4{center_dot}8)-connected network with a Schlafli symbol (4{sup 6})(4{sup 12}{center_dot}6{sup 12}{center_dot}8{sup 4}). Black-Right-Pointing-Pointer Compound 4

  10. Rational Design of Cesium-Selective Ionophores and Chemosensors: Dihydrocalix[4]arene Crown-6 Ethers

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Richard A.; Bryan, Jeffrey C.; Brown, Gilbert M.; Engle, Nancy L.; Haverlock, Tamara J.; Hay, Benjamin P.; Urvoas, Agathe; Moyer, Bruce A.

    2003-12-15

    Molecular mechanics calculations performed on calix[4]arene crown-6 ethers predict that the 1,3-dihydro derivatives will exhibit greater complementarity for potassium and cesium ions than the parent 1,3-dialkoxy calix crowns. The X-ray crystal structures of 1,3-alt bis-octyloxycalix[4]arene benzocrown-6 ether, dihydrocalix[4]arene benzocrown-6 ether, and the cesium nitrate complex of dihydrocalix[4]arene benzocrown-6 ether were determined. The cesium complex structure corresponds closely to the structure predicted by molecular mechanics. The dihydrocalix[4]arene crown-6 ethers exhibit enhanced cesium selectivity in the extraction of alkali metal salts and provide a platform for a highly sensitive and selective cesium chemosensor.

  11. The Synthesis and Anion Recognition Property of Symmetrical Chemosensors Involving Thiourea Groups: Theory and Experiments

    Directory of Open Access Journals (Sweden)

    Xuefang Shang

    2015-11-01

    Full Text Available The synthesis of four symmetrical compounds containing urea/thiourea and anthracene/nitrobenzene groups was optimized. N,N’-Di((anthracen-9-yl-methylene thio-carbonohydrazide showed sensitive and selective binding ability for acetate ion among the studied anions. The presence of other competitive anions including F−, H2PO4−, Cl−, Br− and I− did not interfere with the strong binding ability. The mechanism of the host-guest interaction was through multiple hydrogen bonds due to the conformational complementarity and higher basicity. A theoretical investigation explained that intra-molecular hydrogen bonds existed in the compound which could strengthen the anion binding ability. In addition, molecular frontier orbitals in molecular interplay were introduced in order to explain the red-shift phenomenon in the host-guest interaction process. Compounds based on thiourea and anthracene derivatives can thus be used as a chemosensor for detecting acetate ion in environmental and pharmaceutical samples.

  12. Fluorescent Cross-Linked Supramolecular Polymer Constructed by Orthogonal Self-Assembly of Metal-Ligand Coordination and Host-Guest Interaction.

    Science.gov (United States)

    Qian, Xiaomin; Gong, Weitao; Li, Xiaopeng; Fang, Le; Kuang, Xiaojun; Ning, Guiling

    2016-05-10

    A new host molecule consists of four terpyridine groups as the binding sites with zinc(II) ion and a copillar[5]arene incorporated in the center as a spacer to interact with guest molecule was designed and synthesized. Due to the 120 ° angle of the rigid aromatic segment, a cross-linked dimeric hexagonal supramolecular polymer was therefore generated as the result of the orthogonal self-assembly of metal-ligand coordination and host-guest interaction. UV/Vis spectroscopy, (1) H NMR spectroscopy, viscosity and dynamic light-scattering techniques were employed to characterize and understand the cross-linking process with the introduction of zinc(II) ion and guest molecule. More importantly, well-defined morphology of the self-assembled supramolecular structure can be tuned by altering the adding sequence of the two components, that is, the zinc(II) ion and the guest molecule. In addition, introduction of a competitive ligand suggested the dynamic nature of the supramolecular structure. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Syntheses, structures, fluorescence and thermal properties of three lanthanide coordination polymers built by N-benzoyl-N'-(4-benzoxy)thiourea

    Energy Technology Data Exchange (ETDEWEB)

    Li Zifeng; Cheng Xinxin [Department of Chemistry, Zhengzhou University, Henan 450052 (China); Li Gang, E-mail: gangli@zzu.edu.c [Department of Chemistry, Zhengzhou University, Henan 450052 (China); Lu Huijie; Zhang Haifang [Department of Chemistry, Zhengzhou University, Henan 450052 (China)

    2010-11-15

    Three novel lanthanide 1-D chain coordination polymers, namely {l_brace}[Tb({mu}{sub 2}-L){sub 2}({eta}{sup 2}-NO{sub 3})(CH{sub 3}OH)(H{sub 2}O)].0.5CH{sub 3}OH.0.5H{sub 2}O{r_brace}{sub n} (1), {l_brace}[Dy({mu}{sub 2}-L){sub 2}({eta}{sup 2}-NO{sub 3})(CH{sub 3}OH)(H{sub 2}O)].H{sub 2}O{r_brace}{sub n} (2) and {l_brace}[Ce({mu}{sub 2}-L){sub 2}({eta}{sup 2}-NO{sub 3})(H{sub 2}O){sub 3}].H{sub 2}O{r_brace}{sub n} (3) (HL=N-benzoyl-N'-(4-benzoxy)thiourea), have been prepared and characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The luminescence properties and themostabilities of polymers 1-3 have been determined as well.

  14. Developing a genetically encoded green fluorescent protein mutant for sensitive light-up fluorescent sensing and cellular imaging of Hg(II).

    Science.gov (United States)

    Jiang, Tao; Guo, Daiping; Wang, Qian; Wu, Xin; Li, Zhao; Zheng, Zhenhua; Yin, Boyuan; Xia, Lin; Tang, Jixian; Luo, Wenxin; Xia, Ningshao; Jiang, Yunbao

    2015-05-30

    Hg(II) is well-known for quenching fluorescence in a distance dependent manner. Nevertheless, when we exposed the fluorophore of a green fluorescent protein (GFP) toward Hg(II), through H148C mutation, the GFP fluorescence could be "lighted up" by Hg(II) down to sub-nM level. The detection linear range is 0.5-3.0 nM for protein solutions at 8.0 nM. The GFPH148C protein displayed a promising selectivity toward Hg(II) and also the cellular imaging capacity. Spectra measurements suggested that the ground-state redistribution of protein contributed to the fluorescence enhancement, which was found not limited to Hg(II), and thus presented an opening for building a pool of GFP-based chemosensors toward other heavy metal ions. Copyright © 2015. Published by Elsevier B.V.

  15. Multifunctional Magnetic-fluorescent Nanocomposites for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Rakovich Yury

    2008-01-01

    Full Text Available AbstractNanotechnology is a fast-growing area, involving the fabrication and use of nano-sized materials and devices. Various nanocomposite materials play a number of important roles in modern science and technology. Magnetic and fluorescent inorganic nanoparticles are of particular importance due to their broad range of potential applications. It is expected that the combination of magnetic and fluorescent properties in one nanocomposite would enable the engineering of unique multifunctional nanoscale devices, which could be manipulated using external magnetic fields. The aim of this review is to present an overview of bimodal “two-in-one” magnetic-fluorescent nanocomposite materials which combine both magnetic and fluorescent properties in one entity, in particular those with potential applications in biotechnology and nanomedicine. There is a great necessity for the development of these multifunctional nanocomposites, but there are some difficulties and challenges to overcome in their fabrication such as quenching of the fluorescent entity by the magnetic core. Fluorescent-magnetic nanocomposites include a variety of materials including silica-based, dye-functionalised magnetic nanoparticles and quantum dots-magnetic nanoparticle composites. The classification and main synthesis strategies, along with approaches for the fabrication of fluorescent-magnetic nanocomposites, are considered. The current and potential biomedical uses, including biological imaging, cell tracking, magnetic bioseparation, nanomedicine and bio- and chemo-sensoring, of magnetic-fluorescent nanocomposites are also discussed.

  16. Complex-formation-enhanced fluorescence quenching effect for efficient detection of picric acid.

    Science.gov (United States)

    Ding, Aixiang; Yang, Longmei; Zhang, Yuyang; Zhang, Gaobin; Kong, Lin; Zhang, Xuanjun; Tian, Yupeng; Tao, Xutang; Yang, Jiaxiang

    2014-09-15

    Amine-functionalized α-cyanostilbene derivatives (Z)-2-(4-aminophenyl)-3-(4-butoxyphenyl)acrylonitrile (ABA) and (Z)-3-(4-butoxyphenyl)-2-[4-(butylamino)phenyl]acrylonitrile (BBA) were designed for specific recognition of picric acid (PA), an environmental and biological pollutant. The 1:1 host-guest complexes formed between the chemosensors and PA enhanced fluorescence quenching, thus leading to sensitive and selective detection in aqueous media and the solid phase. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Semi-Interpenetrating Polymer Networks with Predefined Architecture for Metal Ion Fluorescence Monitoring

    Directory of Open Access Journals (Sweden)

    Kyriakos Christodoulou

    2016-11-01

    Full Text Available The development of new synthetic approaches for the preparation of efficient 3D luminescent chemosensors for transition metal ions receives considerable attention nowadays, owing to the key role of the latter as elements in biological systems and their harmful environmental effects when present in aquatic media. In this work, we describe an easy and versatile synthetic methodology that leads to the generation of nonconjugated 3D luminescent semi-interpenetrating amphiphilic networks (semi-IPN with structure-defined characteristics. More precisely, the synthesis involves the encapsulation of well-defined poly(9-anthrylmethyl methacrylate (pAnMMA (hydrophobic, luminescent linear polymer chains within a covalent poly(2-(dimethylaminoethyl methacrylate (pDMAEMA hydrophilic polymer network, derived via the 1,2-bis-(2-iodoethoxyethane (BIEE-induced crosslinking process of well-defined pDMAEMA linear chains. Characterization of their fluorescence properties demonstrated that these materials act as strong blue emitters when exposed to UV irradiation. This, combined with the presence of the metal-binding tertiary amino functionalities of the pDMAEMA segments, allowed for their applicability as sorbents and fluorescence chemosensors for transition metal ions (Fe3+, Cu2+ in solution via a chelation-enhanced fluorescence-quenching effect promoted within the semi-IPN network architecture. Ethylenediaminetetraacetic acid (EDTA-induced metal ion desorption and thus material recyclability has been also demonstrated.

  18. Fluorescent zinc–terpyridine complex containing coordinated ...

    Indian Academy of Sciences (India)

    Unknown

    subject of many investigations on their luminescence behaviour by a number of workers 5. Surprisingly very meagre information is available in the literature on the luminescence behaviour of corresponding transition metal complexes 6. The photo- physical/chemical studies of transition metal terpyridine complexes would be ...

  19. A smart gelator as a chemosensor: application to integrated logic gates in solution, gel, and film.

    Science.gov (United States)

    Xue, Pengchong; Lu, Ran; Jia, Junhui; Takafuji, Makoto; Ihara, Hirotaka

    2012-03-19

    A gelator that consisted of one benzimidazole moiety and four amide units was used as a chemosensor. We found that its absorption and emission spectra in solution were sensitive to two complementary chemical stimuli: protons and anions. Thus, YES and INH logic gates were obtained when absorbance was defined as an output. A combination gate of XNOR and AND with an emission output was also obtained. Moreover, wet gels in two solvents were used to construct two more-complicated three-input-three-output gates, owing to the existence of the gel phase as an additional output. Finally, in xerogel films that were formed from two kinds of wet gels, reversible changes in their emission spectra were observed when they were sequentially exposed to volatile acid and NH(3). Another combination two-output logic gate was obtained for xerogel films. Finally, three states of the gelator were used to construct not only basic logic gate, but also some combination gates because of their response to multiple chemical stimuli and their multiple output signals, in which one chemical input could erase the effect of another chemical input. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. A series of coordination polymers constructed from R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands: Syntheses, structures and fluorescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yong-Hong, E-mail: zhou21921@sina.com [School of Chemistry and Material Science, Huaibei Normal University, Huaibei 235000 (China); Zhou, Xu-Wan; Zhou, Su-Rong [School of Chemistry and Material Science, Huaibei Normal University, Huaibei 235000 (China); Tian, Yu-Peng; Wu, Jie-Ying [Department of Chemistry and Chemical Technology, Anhui University, Hefei 230039 (China)

    2017-01-15

    Six novel Zn(II), Cd(II), and Cu(II) mixed-ligand coordination complexes, namely, [Zn{sub 2}Na(sip){sub 2}(bpp){sub 3}(Hbpp)(H{sub 2}O){sub 2}]·8H{sub 2}O (1), [Cd{sub 3}(sip){sub 2}(nbi){sub 6}(H{sub 2}O){sub 2}]·7H{sub 2}O (2), [Zn(sip)(nbi){sub 2}(H{sub 2}O)]·Hnbi·3H{sub 2}O (3), [Cd(hip)(nbi){sub 2}(H{sub 2}O)]·nbi·5H{sub 2}O (4), [Cd{sub 2}(nip){sub 2}(nbi){sub 2}(H{sub 2}O){sub 2}]·DMF (5), and [Cu(nip)(nbi)(H{sub 2}O){sub 2}]·H{sub 2}O (6) (H{sub 3}sip=5-sulfoisophthalic acid, H{sub 2}hip=5-hydroxylisophthalic acid, H{sub 2}nip=5-nitroisophthalic acid, bpp=1,3-bis(4-pyridyl)propane, and nbi=6-nitrobenzimidazole) have been synthesized hydrothermally by the self-assembly of R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands. Single crystal X-ray analyses reveal that two Zn(II) ions and one Na(I) ion of complex 1 are linked through O atoms to generate a 1D linear chain. Then the 2D supramolecular architectures are constructed via intermolecular interactions. In complex 2, the Cd1 ions are connected by bridging carboxyl groups from sip{sup 3−} anions to form 1D double chain, which are further connected by Cd2 ions to afford 2D layer structure. The adjacent 2D layers are further linked via hydrogen-bonding interactions to give 3D supramolecular network. Compounds 3–5 show 1D chain structures, which are assembled into 2D or 3D supramolecular frameworks via weak interactions. In compound 6, the Cu(II) ions are bridged by the nip{sup 2−} ligands to form 48-membered ring, which is assembled into 1Dchain via the π-π stacking interaction. In addition, the thermal stabilities and fluorescence properties of these compounds have also been studied. - Graphical abstract: A series of Cd(II)/Zn(II)/ Cu(II) coordination polymers based on R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands have been synthesized under hydrothermal conditions and structurally characterized. Photoluminescent properties

  1. Spin filtering effect in colorimetric chemosensor L-based molecular devices modulated with different transition metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Shi, F.V.; Lv, Y.Z. [School of Physics and Technology, University of Jinan, Jinan 250022 (China); Zhao, P., E-mail: ss_zhaop@ujn.edu.cn [School of Physics and Technology, University of Jinan, Jinan 250022 (China); Liu, D.S. [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Department of Physics, Jining University, Jining 273155 (China)

    2017-05-15

    Based on the density functional theory in conjunction with the non-equilibrium Green's function formalism, we explore the effect of transition metal (Mn, Fe, Co, Ni) ions on the magnetic transport properties of a new synthesized colorimetric chemosensor L. The calculated results show that only Mn-L can present high-efficiency spin filtering effect, even at room temperature. The underlying mechanism is explained by the spin-resolved electron occupation number, transmission spectra, molecular projected self-consistent Hamiltonian orbitals and their spatial distribution.

  2. Cerium(III) Ion Sensing Based on Graphene Quantum Dots Fluorescent Turn-Off.

    Science.gov (United States)

    Salehnia, Foad; Faridbod, Farnoush; Dezfuli, Amin Shiralizadeh; Ganjali, Mohammad Reza; Norouzi, Parviz

    2017-01-01

    In this work, graphene quantum dots (GQDs) was synthesized through hydrothermal method and used as a photoluminescent bulk nano-chemosensor for detection of Ce3+ ion in the aqueous solution. The synthesized GQD was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Visible absorption and fluorescence emission spectroscopy. The sheet diameters of the synthesized GQDs were mainly distributed in the range of 15-20 nm. The interactions of GQDs with common cations and lanthanide ions were studied by fluorescence spectroscopy. Among the tested cations, Ce3+ ions was able to quench the fluorescence emission intensity of the GQD selectively. This quenching can be attributed to a redox mechanism between Ce3+ ion on the GQDs surface.

  3. Fluorescence and Sensing Applications of Graphene Oxide and Graphene Quantum Dots: A Review.

    Science.gov (United States)

    Zheng, Peng; Wu, Nianqiang

    2017-09-19

    Graphene oxide and graphene quantum dots are attractive fluorophores that are inexpensive, nontoxic, photostable, water-soluble, biocompatible, and environmentally friendly. They find extensive applications in fluorescent biosensors and chemosensors, in which they serve as either fluorophores or quenchers. As fluorophores, they display tunable photoluminescence emission and the "giant red-edge effect". As quenchers, they exhibit a remarkable quenching efficiency through either electron transfer or Förster resonance energy transfer (FRET) process. In this review, the origin of fluorescence and the mechanism of excitation wavelength-dependent fluorescence of graphene oxide and graphene quantum dots are discussed. Sensor design strategies based on graphene oxide and graphene quantum dots are presented. The applications of these sensors in health care, the environment, agriculture, and food safety are highlighted. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Imprinting of Molecular Recognition Sites on Nanostructures and Its Applications in Chemosensors

    Directory of Open Access Journals (Sweden)

    Bianhua Liu

    2008-12-01

    Full Text Available Biological receptors including enzymes, antibodies and active proteins have been widely used as the detection platform in a variety of chemo/biosensors and bioassays. However, the use of artificial host materials in chemical/biological detections has become increasingly attractive, because the synthetic recognition systems such as molecularly imprinted polymers (MIPs usually have lower costs, higher physical/chemical stability, easier preparation and better engineering possibility than biological receptors. Molecular imprinting is one of the most efficient strategies to offer a synthetic route to artificial recognition systems by a template polymerization technique, and has attracted considerable efforts due to its importance in separation, chemo/biosensors, catalysis and biomedicine. Despite the fact that MIPs have molecular recognition ability similar to that of biological receptors, traditional bulky MIP materials usually exhibit a low binding capacity and slow binding kinetics to the target species. Moreover, the MIP materials lack the signal-output response to analyte binding events when used as recognition elements in chemo/biosensors or bioassays. Recently, various explorations have demonstrated that molecular imprinting nanotechniques may provide a potential solution to these difficulties. Many successful examples of the development of MIP-based sensors have also been reported during the past several decades. This review will begin with a brief introduction to the principle of molecular imprinting nanotechnology, and then mainly summarize various synthesis methodologies and recognition properties of MIP nanomaterials and their applications in MIP-based chemosensors. Finally, the future perspectives and efforts in MIP nanomaterials and MIP-based sensors are given.

  5. A highly sensitive, single selective, fluorescent sensor for Al{sup 3+} detection and its application in living cell imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Xing-Pei [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Sun, Shao-bo; Li, Ying-dong [Institute of Integrated Traditional and Western Medicine, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Zhi, Li-hua [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Wu, Wei-na, E-mail: wuwn08@hpu.edu.cn [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Wang, Yuan, E-mail: wangyuan08@hpu.edu.cn [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China)

    2014-11-15

    A new o-aminophenol-based fluorogenic chemosensor methyl 3,5-bis((E)-(2-hydroxyphenylimino)methyl)-4-hydroxybenzoate 1 have been synthesized by Schiff base condensation of methyl 3,5-diformyl-4-hydroxybenzoate with o-aminophenol, which exhibits high selectivity and sensitivity toward Al{sup 3+}. Fluorescence titration studies of receptors 1 with different metal cations in CH{sub 3}OH medium showed highly selective and sensitive towards Al{sup 3+} ions even in the presence of other commonly coexisting metal ions. The detection limit of Al{sup 3+} ions is at the parts per billion level. Interestingly, the Al(III) complex of 1 offered a large Stokes shift (>120 nm), which can miximize the selfquenching effect. In addition, possible utilization of this receptor as bio-imaging fluorescent probe to detect Al{sup 3+} in human cervical HeLa cancer cell lines was also investigated by confocal fluorescence microscopy. - Highlights: • A new Schiff base chemosensor is reported. • The sensor for Al{sup 3+} offers large Stokes shift. • The detection limit of Al{sup 3+} in CH{sub 3}OH solution is at the parts per billion level. • The utilization of sensor for the monitoring of Al{sup 3+} levels in living cells was examined.

  6. TECHNICAL COORDINATION

    CERN Multimedia

    A. Ball

    Overview From a technical perspective, CMS has been in “beam operation” state since 6th November. The detector is fully closed with all components operational and the magnetic field is normally at the nominal 3.8T. The UXC cavern is normally closed with the radiation veto set. Access to UXC is now only possible during downtimes of LHC. Such accesses must be carefully planned, documented and carried out in agreement with CMS Technical Coordination, Experimental Area Management, LHC programme coordination and the CCC. Material flow in and out of UXC is now strictly controlled. Access to USC remains possible at any time, although, for safety reasons, it is necessary to register with the shift crew in the control room before going down.It is obligatory for all material leaving UXC to pass through the underground buffer zone for RP scanning, database entry and appropriate labeling for traceability. Technical coordination (notably Stephane Bally and Christoph Schaefer), the shift crew and run ...

  7. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...... the foundations of the fluorescence phenomenon, introduces some general methodologies and provides selected examples on applications focused to disentangle structural and dynamical aspects of biological processes....

  8. Hg2+-reactive double hydrophilic block copolymer assemblies as novel multifunctional fluorescent probes with improved performance.

    Science.gov (United States)

    Hu, Jinming; Li, Changhua; Liu, Shiyong

    2010-01-19

    We report on novel type of responsive double hydrophilic block copolymer (DHBC)-based multifunctional chemosensors to Hg(2+) ions, pH, and temperatures and investigate the effects of thermo-induced micellization on the detection sensitivity. Well-defined DHBCs bearing rhodamine B-based Hg(2+)-reactive moieties (RhBHA) in the thermo-responsive block, poly(ethylene oxide)-b-poly(N-isopropylacrylamide-co-RhBHA) (PEO-b-P(NIPAM-co-RhBHA)), were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Nonfluorescent RhBHA moieties are subjected to selective ring-opening reaction upon addition of Hg(2+) ions or lowering solution pH, producing highly fluorescent acyclic species. Thus, at room temperature PEO-b-P(NIPAM-co-RhBHA) DHBCs can serve as water-soluble multifunctional and efficient fluorescent chemosensors to Hg(2+) ions and pH. Upon heating above the lower critical solution temperature (approximately 36 degrees C) of the PNIPAM block, they self-assemble into micelles possessing P(NIPAM-co-RhBHA) cores and well-solvated PEO coronas, which were fully characterized by dynamic and static laser light scattering. It was found that the detection sensitivity to Hg(2+) ions and pH could be dramatically improved at elevated temperatures due to fluorescence enhancement of RhBHA residues in the acyclic form, which were embedded within hydrophobic cores of thermo-induced micellar aggregates. This work represents a proof-of-concept example of responsive DHBC-based multifunctional fluorescent chemosensors for the highly efficient detection of Hg(2+) ions, pH, and temperatures with tunable detection sensitivity. Compared to reaction-based small molecule Hg(2+) probes in previous literature reports, the integration of stimuli-responsive block copolymers with well-developed small molecule-based selective sensing moieties in the current study are expected to exhibit preferred advantages including enhanced detection sensitivity, water dispersibility

  9. TECHNICAL COORDINATION

    CERN Multimedia

    A. Ball

    2010-01-01

    Operational Experience At the end of the first full-year running period of LHC, CMS is established as a reliable, robust and mature experiment. In particular common systems and infrastructure faults accounted for <0.6 % CMS downtime during LHC pp physics. Technical operation throughout the entire year was rather smooth, the main faults requiring UXC access being sub-detector power systems and rack-cooling turbines. All such problems were corrected during scheduled technical stops, in the shadow of tunnel access needed by the LHC, or in negotiated accesses or access extensions. Nevertheless, the number of necessary accesses to the UXC averaged more than one per week and the technical stops were inevitably packed with work packages, typically 30 being executed within a few days, placing a high load on the coordination and area management teams. It is an appropriate moment for CMS Technical Coordination to thank all those in many CERN departments and in the Collaboration, who were involved in CMS techni...

  10. Ferrocenyl Chalcone with 2-Anthracenyl Group (2-Anth-C(O)CH=CHFc): Electrochemical and Fluorescent Properties

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su Kyung; Lim, Chae Mi; Lee, Ji Yeon; Noh, Dong Youn [Seoul Women' s University, Seoul (Korea, Republic of)

    2011-01-15

    In this study, a ferrocenyl chalcone with a 2-anthracenyl group, an analogue of was prepared. Unlike is fluorescent and its fluorescence was investigated in relation to its solvent's polarity. Its electrochemical properties were also studied and the local geometry of is suggested from {sup 1}H NMR results. Ferrocenyl chalcones, in which ferrocenyl and aromatic groups are linked by an enone bridge, are versatile compounds exhibiting antiplasmodial and antitumor activities, fluorescent and electrochemical properties, and molecular chemosensor activity. Ferrocenyl chalcones bearing the fluorophores such as 2-naphthalene, 9-anthracene, 1-pyrene, and N-ethyl carbazole, are regarded as good candidates for new fluorescent material. However, ferrocenyl chalcones containing 9-anthracene and 2-naphthalene derivatives have been reported as being not fluorescent, while those containing 1-pyrene and N-ethyl carbazole derivatives are fluorescent. It means that the ferrocenyl group, known as an effective quencher of exited states, is therefore not the only reason why they are non-fluorescent. Some derivatization of fluoro-phores can also disable fluorescence, as demonstrated by 2-acetylanthracene being fluorescent while 9-acetylanthracene is not.

  11. A new unsymmetrical azine derivative based on coumarin group as dual-modal sensor for CN- and fluorescent "OFF-ON" for Zn2 +

    Science.gov (United States)

    Hu, Jing-Han; Sun, You; Qi, Jing; Li, Qiao; Wei, Tai-Bao

    2017-03-01

    A simple chemosensor YS based on coumarin group was designed and synthesized. Its structure was determined by single crystal X-ray diffraction analysis. In the presence of cyanide the sensor showed an immediate visible change in color from colorless to pale yellow by naked-eyes and produced a strong blue fluorescence rapidly in DMSO/H2O (3:7, v/v). The detection limit on fluorescence response of the sensor to CN- is down to 1.69 × 10- 7 M. In addition YS could show fluorescence turn-on response rapidly for Zn2 + over other metals ions such as Fe3 +, Hg2 +, Ag+, Ca2 +, Cu2 +, Co2 +, Ni2 +, Cd2 +, Pb2 +, Cr3 + and Mg2 + in aqueous solutions. Notably, this sensor served as a molecular switch, which was controlled by Zn2 + and EDTA cyclically. Test strips based on YS were fabricated, which could act as a convenient and efficient CN- and Zn2 + test kit. This chemosensor could achieve the detection of two ions, which need not depend on two different sensors.

  12. Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

    Directory of Open Access Journals (Sweden)

    Milo Malanga

    2014-12-01

    Full Text Available The fluorescent tagging of cyclodextrin derivatives enlarges their spectroscopic properties thus generating chemosensors, biological tools for visualization and sophisticated photoresponsive devices. Cyclodextrin polymers, due to the cooperative interactions, exhibit additional properties compared to their monomeric counterpart. These macromolecules can be prepared either in well water-soluble form or as gels of high swelling. Two versatile synthetic strategies for introducing a fluorescent tag (rhodamine, fluorescein, nitrobenzofuran or coumarin into the water-soluble epichlorohydrin branched cyclodextrin polymers were worked out and compared. The fluorescent labeling was realized in three steps: 1 building in azido moieties, 2 transforming the azido groups into amino groups and 3 coupling the proper fluorescent compound to the amino groups. The other strategy started by functionalization of the monomer prior to the branching. Either the fluorescent-labeled monomer or the intermediate azido derivative of the monomer was branched. Further tuning of the properties of the polymer was achieved via branching of the methylated cyclodextrin derivative. The key intermediates and the fluorescent final products were characterized by various spectroscopic techniques and capillary electrophoresis. The applied synthetic routes were evaluated based on the molecular weight, cyclodextrin content of the products and the efficiency of labeling.

  13. Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers.

    Science.gov (United States)

    Malanga, Milo; Bálint, Mihály; Puskás, István; Tuza, Kata; Sohajda, Tamás; Jicsinszky, László; Szente, Lajos; Fenyvesi, Éva

    2014-01-01

    The fluorescent tagging of cyclodextrin derivatives enlarges their spectroscopic properties thus generating chemosensors, biological tools for visualization and sophisticated photoresponsive devices. Cyclodextrin polymers, due to the cooperative interactions, exhibit additional properties compared to their monomeric counterpart. These macromolecules can be prepared either in well water-soluble form or as gels of high swelling. Two versatile synthetic strategies for introducing a fluorescent tag (rhodamine, fluorescein, nitrobenzofuran or coumarin) into the water-soluble epichlorohydrin branched cyclodextrin polymers were worked out and compared. The fluorescent labeling was realized in three steps: 1) building in azido moieties, 2) transforming the azido groups into amino groups and 3) coupling the proper fluorescent compound to the amino groups. The other strategy started by functionalization of the monomer prior to the branching. Either the fluorescent-labeled monomer or the intermediate azido derivative of the monomer was branched. Further tuning of the properties of the polymer was achieved via branching of the methylated cyclodextrin derivative. The key intermediates and the fluorescent final products were characterized by various spectroscopic techniques and capillary electrophoresis. The applied synthetic routes were evaluated based on the molecular weight, cyclodextrin content of the products and the efficiency of labeling.

  14. RUN COORDINATION

    CERN Multimedia

    C. Delaere

    2013-01-01

    Since the LHC ceased operations in February, a lot has been going on at Point 5, and Run Coordination continues to monitor closely the advance of maintenance and upgrade activities. In the last months, the Pixel detector was extracted and is now stored in the pixel lab in SX5; the beam pipe has been removed and ME1/1 removal has started. We regained access to the vactank and some work on the RBX of HB has started. Since mid-June, electricity and cooling are back in S1 and S2, allowing us to turn equipment back on, at least during the day. 24/7 shifts are not foreseen in the next weeks, and safety tours are mandatory to keep equipment on overnight, but re-commissioning activities are slowly being resumed. Given the (slight) delays accumulated in LS1, it was decided to merge the two global runs initially foreseen into a single exercise during the week of 4 November 2013. The aim of the global run is to check that we can run (parts of) CMS after several months switched off, with the new VME PCs installed, th...

  15. RUN COORDINATION

    CERN Multimedia

    Christophe Delaere

    2013-01-01

    The focus of Run Coordination during LS1 is to monitor closely the advance of maintenance and upgrade activities, to smooth interactions between subsystems and to ensure that all are ready in time to resume operations in 2015 with a fully calibrated and understood detector. After electricity and cooling were restored to all equipment, at about the time of the last CMS week, recommissioning activities were resumed for all subsystems. On 7 October, DCS shifts began 24/7 to allow subsystems to remain on to facilitate operations. That culminated with the Global Run in November (GriN), which   took place as scheduled during the week of 4 November. The GriN has been the first centrally managed operation since the beginning of LS1, and involved all subdetectors but the Pixel Tracker presently in a lab upstairs. All nights were therefore dedicated to long stable runs with as many subdetectors as possible. Among the many achievements in that week, three items may be highlighted. First, the Strip...

  16. Discovery of a novel calcium-sensitive fluorescent probe for α-ketoglutarate.

    Science.gov (United States)

    Gan, Lin-Lin; Chen, Lin-Hai; Nan, Fa-Jun

    2017-12-01

    α-Ketoglutarate (α-KG), a pivotal metabolite in energy metabolism, has been implicated in nonalcoholic fatty liver disease (NAFLD) and several cancers. It is recently proposed that plasma α-KG is a surrogate biomarker of NAFLD. Here, we report the development of a novel "turn-on" chemosensor for α-KG that contains a coumarin moiety as a fluorophore. Using benzothiazole-coumarin (BTC) as inspiration, we designed a probe for calcium ion recognition that possesses a unique fluorophore compared with previously reported probes for α-KG measurement. This chemosensor is based on the specific Schiff base reaction and the calcium ion recognition property of the widely used calcium indicator BTC. The probe was synthesized, and a series of parallel experiments were conducted to optimize the chemical recognition process. Compared to the initial weak fluorescence, a remarkable 7.6-fold enhancement in fluorescence intensity (I/I0 at 495 nm) was observed for the conditions in which the probe (1 μmol/L), α-KG (50 μmol/L), and Ca2+ (100 μmol/L) were incubated at 30 °C in EtOH. The probe displayed good selectivity for α-KG even in an environment with an abundance of amino acids and other interfering species such as glutaric acid. We determined that the quantitative detection range of α-KG in EtOH was between 5 and 50 μmol/L. Finally, probe in serum loaded with α-KG (10 mmol/L) showed a 7.4-fold fluorescence enhancement. In summary, a novel probe for detecting the biomarker α-KG through a typical Schiff base reaction has been discovered. With further optimization, this probe may be a good alternative for detecting the physiological metabolite α-KG.

  17. A simplistic approach to green future with eco-friendly luminescent carbon dots and their application to fluorescent nano-sensor 'turn-off' probe for selective sensing of copper ions.

    Science.gov (United States)

    Das, Poushali; Ganguly, Sayan; Bose, Madhuparna; Mondal, Subhadip; Das, Amit Kumar; Banerjee, Susanta; Das, Narayan Chandra

    2017-06-01

    Zero-dimensional fluorescent nanoparticles having specificity as molecular probe appears to be strategically balanced fluorescent nano-probes. In this work, purified lemon extract and l-arginine have been thermally coupled for the extremely acute detection of Cu(2+) in aqueous medium. The Cu(2+) ions may be captured by the amino groups on the surface of the nano-sensor to form cupric ammine complex resulting in quenched fluorescence via an inner filter effect. Our proposed nano-probe is N-doped carbon dots (NCDs) which are efficiently selective as fluorescent chemosensor due to enormous binding affinity towards Cu(2+) in a wide range of concentration (0.05-300μM) within a few minutes. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Octanuclear cubic coordination cages.

    Science.gov (United States)

    Tidmarsh, Ian S; Faust, Thomas B; Adams, Harry; Harding, Lindsay P; Russo, Luca; Clegg, William; Ward, Michael D

    2008-11-12

    Two new bis-bidentate bridging ligands have been prepared, L (naph) and L (anth), which contain two chelating pyrazolyl-pyridine units connected to an aromatic spacer (naphthalene-1,5-diyl and anthracene-9,10-diyl respectively) via methylene connectors. Each of these reacts with transition metal dications having a preference for octahedral coordination geometry to afford {M 8L 12} (16+) cages (for L (anth), M = Cu, Zn; for L (naph), M = Co, Ni, Cd) which have an approximately cubic arrangement of metal ions with a bridging ligand spanning each of the twelve edges, and a large central cavity containing a mixture of anions and/or solvent molecules. The cages based on L (anth) have two cyclic helical {M 4L 4} faces, of opposite chirality, connected by four additional L (anth) ligands as "pillars"; all metal centers have a meridional tris-chelate configuration. In contrast the cages based on L (naph) have (noncrystallographic) S 6 symmetry, with a diagonally opposite pair of corners having a facial tris-chelate configuration with the other six being meridional. An additional significant difference between the two types of structure is that the cubes containing L (anth) do not show significant interligand aromatic stacking interactions. However, in the cages based on L (naph), there are six five-membered stacks of aromatic ligand fragments around the periphery, each based on an alternating array of electron-rich (naphthyl) and electron-deficient (pyrazolyl-pyridine, coordinated to M (2+)) aromatic units. A consequence of this is that the cages {M 8(L (naph)) 12} (16+) retain their structural integrity in polar solvents, in contrast to the cages {M 8(L (anth)) 12} (16+) which dissociate in polar solvents. Consequently, the cages {M 8(L (naph)) 12} (16+) give NMR spectra in agreement with the symmetry observed in the solid state, and their fluorescence spectra (for M = Cd) display (in addition to the normal naphthalene-based pi-pi* fluorescence) a lower-energy exciplex

  19. Fluorescent Sensing of Chlorophenols in Water Using an Azo Dye Modified β-Cyclodextrin Polymer

    Science.gov (United States)

    Ncube, Phendukani; Krause, Rui W.; Mamba, Bhekie B.

    2011-01-01

    A water soluble azo dye modified β-cyclodextrin polymer 4 was synthesized and used as a chemosensor for the detection of chlorinated phenols, model chlorinated by-products (CBPs) of water treatment for drinking purposes. The characterization of the intermediates and the azo dye modified β-CD polymer was done by UV/Vis Spectrophotometry, FT-IR and 1H-NMR spectroscopies. The chlorophenols were capable of quenching the fluorescence of the polymer. The polymer showed greater sensitivity towards 2,4-dichlorophenol, with a sensitivity factor of 0.35 compared to 0.05 and 0.12 for phenol and 4-chlorophenol, respectively. The stability constants (Ks) of the pollutants were also determined by the Benesi-Hildebrand method to be 2.104 × 103 M−1 for 2,4-dichlorophenol and 1.120 × 102 M−1 for 4-chlorophenol. PMID:22163864

  20. A multifunctional Schiff base as a fluorescence sensor for Fe3 + and Zn2 + ions, and a colorimetric sensor for Cu2 + and applications

    Science.gov (United States)

    Tang, Xu; Han, Juan; Wang, Yun; Ni, Liang; Bao, Xu; Wang, Lei; Zhang, Wenli

    2017-02-01

    Chemosensors play important parts in the selective recognition of ions, which is widely applied in various fields of environment, industry and biological sciences. In this work, a chemosensor for multi-metal ions based on rhodamine B derivative was synthesized, which could selectively recognize various metal ions in different solvent system. The addition of Cu2 + caused the color change from colorless to pink in EtOH/H2O (v/v = 1:1) solvent system, which could be quickly identified by the naked eyes with a detection limit of 8.27 × 10- 8 M. In ethanol solution system, the addition of Fe3 + and Zn2 + caused different fluorescence changes with the detection limit of 2.12 × 10- 7 M and 6.64 × 10- 7 M respectively. The binding ratios are 1:1 (1-Cu2 +), 2:1 (1-Fe3 +) and 1:1 (1-Zn2 +), respectively. Meanwhile, the probe 1 was used to detect the trace metal ions in real water samples. Besides, the probe 1 showed sensitive fluorescence signals for Fe3 + in biological cells. The experimental results further verify the application value of the sensor.

  1. Fluorescent sensors based on quinoline-containing styrylcyanine: determination of ferric ions, hydrogen peroxide, and glucose, pH-sensitive properties and bioimaging.

    Science.gov (United States)

    Yang, Xiaodong; Zhao, Peiliang; Qu, Jinqing; Liu, Ruiyuan

    2015-08-01

    A novel styrylcyanine-based fluorescent probe 1 was designed and synthesized via facile methods. Ferric ions quenched the fluorescence of probe 1, whereas the addition of ferrous ions led to only small changes in the fluorescence signal. When hydrogen peroxide was introduced into the solution containing probe 1 and Fe(2+) , Fe(2+) was oxidized to Fe(3+), resulting in the quenching of the fluorescence. The probe 1/Fe(2+) solution fluorescence could also be quenched by H2 O2 released from glucose oxidation by glucose oxidase (GOD), which means that probe 1/Fe(2+) platform could be used to detect glucose. Probe 1 is fluorescent in basic and neutral media but almost non-fluorescent in strong acidic environments. Such behaviour enables it to work as a fluorescent pH sensor in both the solution and solid states and as a chemosensor for detecting volatile organic compounds with high acidity and basicity. Subsequently, the fluorescence microscopic images of probe 1 in live cells and in zebrafish were achieved successfully, suggesting that the probe has good cell membrane permeability and a potential application for imaging in living cells and living organisms. Copyright © 2014 John Wiley & Sons, Ltd.

  2. In vivo fluorescence imaging of bacteriogenic cyanide in the lungs of live mice infected with cystic fibrosis pathogens.

    Directory of Open Access Journals (Sweden)

    Seong-Won Nam

    Full Text Available BACKGROUND: Pseudomonas aeruginosa (PA and Burkholderia cepacia complex (Bcc, commonly found in the lungs of cystic fibrosis (CF patients, often produce cyanide (CN, which inhibits cellular respiration. CN in sputa is a potential biomarker for lung infection by CF pathogens. However, its actual concentration in the infected lungs is unknown. METHODS AND FINDINGS: This work reports observation of CN in the lungs of mice infected with cyanogenic PA or Bcc strains using a CN fluorescent chemosensor (4',5'-fluorescein dicarboxaldehyde with a whole animal imaging system. When the CN chemosensor was injected into the lungs of mice intratracheally infected with either PA or B. cepacia strains embedded in agar beads, CN was detected in the millimolar range (1.8 to 4 mM in the infected lungs. CN concentration in PA-infected lungs rapidly increased within 24 hours but gradually decreased over the following days, while CN concentration in B. cepacia-infected lungs slowly increased, reaching a maximum at 5 days. CN concentrations correlated with the bacterial loads in the lungs. In vivo efficacy of antimicrobial treatments was tested in live mice by monitoring bacteriogenic CN in the lungs. CONCLUSIONS: The in vivo imaging method was also found suitable for minimally invasive testing the efficacy of antibiotic compounds as well as for aiding the understanding of bacterial cyanogenesis in CF lungs.

  3. A new rhodamine based 'turn-on'Cu²⁺ ion selective chemosensor in ...

    Indian Academy of Sciences (India)

    ... to Cu²⁺ ion-assisted hydrolysis followed by spirolactam ring opening of the probe (L) in 20mM HEPES buffer [pH 7.4; water/acetonitrile (9:1 v/v)]. The competitive ions do not affect the selectivity and specificity of the probe (L) in the detection of Cu²⁺ ions. The cell imaging study using fluorescence microscope showed that ...

  4. The role of structure and the metal ion in the fluorescence sensing of nitro compounds for a series of lanthanide(iii) 9,10-anthracene dicarboxylate coordination polymers.

    Science.gov (United States)

    Quah, Hong Sheng; Ng, Li Ting; Vittal, Jagadese J

    2017-12-19

    Twenty-eight lanthanide coordination polymers (CPs) containing 9,10-anthracene dicarboxylate (ADC) linkers have been synthesized and characterized. For the earlier class of lanthanides La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+ and Tb3+, the 3D pcu net was generated from dimethylformamide (DMF) while a 2D hcb net was formed using dimethylacetamide (DMA). Similarly for the later class of lanthanides, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+, a 2D hcb net was formed when dimethylacetamide (DMA) was used. However, the formation of a crystalline product with DMF was possible only when DMSO was added together for these lanthanides, and they yielded 2D structures despite the usage of DMF. Only the single crystal structures of Er3+ and Ho3+ have been determined and the rest of the structures were confirmed by PXRD studies. These compounds have been used to sense various nitro compounds. In particular, they are the most sensitive to Brady's reagent, 2,4-dinitrohydrazobenzene. There was no difference in the quenching extent between the 3D and 2D early lanthanide CPs. For the later lanthanides which adopt 2D structures, the quenching efficiency is higher when DMA instead of DMSO is coordinated suggesting the solvent effect in emission quenching.

  5. Study on the Reactivity of Amino Acid Chemosensor, NPFNP, with Ethanol: Structural Elucidation through Single Crystal XRD and DFT Calculations

    Directory of Open Access Journals (Sweden)

    Beena Varghese

    2017-01-01

    Full Text Available A novel ethoxy derivative of an amino acid chemosensor, 3-naphthyl-1-phenyl-5-(2ʹ-fluoro-5ʹ-nitrophenyl-2-pyrazoline (NPFNP, has been synthesized and characterized by different spectroscopic methods.  A single crystal of the ethoxy derivative, 3-naphthyl-1-phenyl-5-(2ʹ-ethoxy-5ʹ-nitrophenyl-2-pyrazoline NPENP, has been obtained and characterized.  The structure holds interest as it carries biologically active pyrazoline as a central ring attaching to electron donating and withdrawing substituents. The major motivation for this work was to gain detailed insight into the structural parameters of this compound for investigating the influence of crystal packing and geometrical dimensions on optical properties. Time-dependent DFT calculations have been employed for comparing the XRD data with theoretical parameters. The results show that the DFT method at B3LYP/6-31G level can well reproduce the structure of the title compound.

  6. Anionic chromogenic chemosensors highly selective for fluoride or cyanide based on 4-(4-Nitrobenzylideneamine)phenol

    Energy Technology Data Exchange (ETDEWEB)

    Nicoleti, Celso R.; Marini, Vanderleia G.; Zimmermann, Lizandra M.; Machado, Vanderlei G., E-mail: vanderlei.machado@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-08-15

    4-(4-Nitrobenzylideneamine)phenol was used in two strategies allowing the highly selective detection of F{sup -} and CN{sup -}. Firstly, the compound in acetonitrile acts as a chromogenic chemosensor based on the idea that more basic anions cause its deprotonation (colorless solution), generating a colored solution containing phenolate. The discrimination of CN{sup -} over F{sup -} was obtained by adding 1.4% water to acetonitrile: water preferentially solvates F{sup -}, leaving the CN{sup -} free to deprotonate the compound. Another strategy involved an assay comprised of the competition between phenolate dye and the analyte for calyx[4]pyrrole in acetonitrile, a receptor highly selective for F{sup -}. Phenolate and calyx[4]pyrrole form a hydrogen-bonded complex, which changes the color of the medium. On the addition of various anions, only F{sup -} was able to restore the original color corresponding to phenolate in solution due to the fact that the anion dislodges phenolate from the complexation site. (author)

  7. Cation coordination induced modulation of the anion sensing properties of a ferrocene-imidazophenanthroline dyad: multichannel recognition from phosphate-related to chloride anions.

    Science.gov (United States)

    Zapata, Fabiola; Caballero, Antonio; Espinosa, Arturo; Tárraga, Alberto; Molina, Pedro

    2008-06-06

    A new chemosensor molecule 1 based on a ferrocene-imidazophenanthroline dyad, effectively recognizes aqueous hydrogenpyrophosphate and the organic anions ADP and ATP through three different channels. A cathodic shift of the ferrocene/ferrocenium oxidation wave (Delta E 1/2 ranging from -130 mV for hydrogenpyrophosphate and fluoride to -40 mV for ADP). A progressive red-shift of the absorption bands and/or appearance of a new low energy band at 314-319 nm. These changes in the absorption spectra are accompanied by color changes from pale yellow to orange or pink, which allow the potential for "naked eye" detection. The emission spectrum (lambda exc = 390 nm) undergoes an important chelation-enhanced fluorescence effect (CHEF = 50) in the presence of 2.5 equiv of hydrogenpyrophosphate anion and with a large excess of fluoride anion (CHEF = 114). Interestingly, the emission spectrum obtained at different excitation energy (lambda exc = 340 nm) in the presence of AcOH acid is red-shifted and not only perturbed by the hydrogenpyrophosphate anion (CHEF = 71) but also with the organic anions ATP (CHEF = 25), ADP (CHEF = 15), and the dihydrogenphosphate (CHEF = 25). The stable heterobimetallic ruthenium (II) complex 2 selectively senses the chloride anion over other anions examined through two channels: cathodic redox shift (Delta E 1/2 = -80 mV) of the Fe(II)/Fe(III) redox couple keeping the oxidation wave of the ruthenium (II) center unchanged and a significant red emission enhancement (CHEF = 30). (1)H and (31)P NMR studies as well as DFT calculations have been carried out to get information about which molecular sites are involved in bonding. About the deprotonation/coordination dualism, the combined electrochemical, absorption, emission, and NMR data strongly support that fluoride anion induces only deprotonation, anions dihydrogenphosphate, ATP, and ADP from hydrogen-bonded complexes and formation of hydrogen-bonded complex between receptor 1 and

  8. Cationic zinc (II) dimers and one dimensional coordination polymer ...

    Indian Academy of Sciences (India)

    A zinc coordination polymer was synthesised by treating in situ generation of 2 in the presence of 4,4′-bipyridine. These new molecules, dimers and polymer, were characterized by FT-IR, NMR, UV-vis, fluorescent and single crystal X-ray diffraction techniques. Zinc polymer is the first example of 1D coordination polymer ...

  9. Fluorescence microscopy.

    Science.gov (United States)

    Sanderson, Michael J; Smith, Ian; Parker, Ian; Bootman, Martin D

    2014-10-01

    Fluorescence microscopy is a major tool with which to monitor cell physiology. Although the concepts of fluorescence and its optical separation using filters remain similar, microscope design varies with the aim of increasing image contrast and spatial resolution. The basics of wide-field microscopy are outlined to emphasize the selection, advantages, and correct use of laser scanning confocal microscopy, two-photon microscopy, scanning disk confocal microscopy, total internal reflection, and super-resolution microscopy. In addition, the principles of how these microscopes form images are reviewed to appreciate their capabilities, limitations, and constraints for operation. © 2014 Cold Spring Harbor Laboratory Press.

  10. Coumarin-based thiol chemosensor: synthesis, turn-on mechanism, and its biological application.

    Science.gov (United States)

    Jung, Hyo Sung; Ko, Kyoung Chul; Kim, Gun-Hee; Lee, Ah-Rah; Na, Yun-Cheol; Kang, Chulhun; Lee, Jin Yong; Kim, Jong Seung

    2011-03-18

    A new chemodosimetric probe (1) is reported that selectively detects thiols over other relevant biological species by the turning on of its fluorescence through a Michael type reaction. The fluorogenic process upon its reaction was revealed to be mediated by intramolecular charge transfer, as confirmed by time-dependent density functional theory calculations. The application of probe 1 to cells is also examined by confocal microscopy, and its cysteine preference was observed by an ex vivo LC-MS analysis of the cellular metabolite.

  11. Coordination Polymer Gels with Modular Nanomorphologies, Tunable Emissions, and Stimuli-Responsive Behavior Based on an Amphiphilic Tripodal Gelator.

    Science.gov (United States)

    Sutar, Papri; Maji, Tapas Kumar

    2017-08-21

    The recent upsurge in research on coordination polymer gels (CPGs) stems from their synthetic modularity, nanoscale processability, and versatile functionalities. Here we report self-assembly of an amphiphilic, tripodal low-molecular weight gelator (L) that consists of 4,4',4-[1,3,5-phenyl-tri(methoxy)]-tris-benzene core and 2,2':6',2″-terpyridyl termini, with different metal ions toward the formation of CPGs that show controllable nanomorphologies, tunable emission, and stimuli-responsive behaviors. L can also act as a selective chemosensor for Zn(II) with very low limit of detection (0.18 ppm) in aqueous medium. Coordination-driven self-assembly of L with Zn(II) in H2O/MeOH solvent mixture results in a coordination polymer hydrogel (ZnL) that exhibits sheet like morphology and charge-transfer emission. On the other hand, coordination of L with Tb(III) and Eu(III) in CHCl3/tetrahydrofuran solvent mixture results in green- and red-emissive CPGs, respectively, with nanotubular morphology. Moreover, precise stoichiometric control of L/Eu(III)/Tb(III) ratio leads to the formation of bimetallic CPGs that show emissions over a broad spectral range, including white-light-emission. We also explore the multistimuli responsive properties of the white-light-emitting CPG by exploiting the dynamics of Ln(III)-tpy coordination.

  12. Time-Resolved Laser Fluorescence Spectroscopy Study of the Coordination Chemistry of a Hydrophilic CHON [1,2,3-Triazol-4-yl]pyridine Ligand with Cm(III) and Eu(III).

    Science.gov (United States)

    Wagner, Christoph; Mossini, Eros; Macerata, Elena; Mariani, Mario; Arduini, Arturo; Casnati, Alessandro; Geist, Andreas; Panak, Petra J

    2017-02-20

    The complexation of Cm(III) and Eu(III) with the novel i-SANEX complexing agent 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine (PTD) was studied by time-resolved laser fluorescence spectroscopy (TRLFS). The formation of 1:3, 1:2, and 1:1 metal/ligand complexes was identified upon increasing PTD concentration in 10(-3) mol/L HClO4 and in 0.44 mol/L HNO3 solutions. For all these complexes, stability constants were determined at different acid concentrations. Though under the extraction conditions proposed for an An/Ln separation process, that is, for 0.08 mol/L PTD in 0.44 mol/L HNO3, 1:3 complexes represent the major species, a significant fraction of 1:2 complexes was found. This is caused by ligand protonation, and results in lower Eu(III)/Am(III) separation factors compared to SO3-Ph-BTP, until now considered the i-SANEX reference ligand. Focused extraction studies performed at lower proton concentration, where the 1:3 complex is formed exclusively, confirm this assumption.

  13. Strong Fluorescent Smart Organogel as a Dual Sensing Material for Volatile Acid and Organic Amine Vapors.

    Science.gov (United States)

    Xue, Pengchong; Yao, Boqi; Wang, Panpan; Gong, Peng; Zhang, Zhenqi; Lu, Ran

    2015-11-23

    An L-phenylalanine derivative (C12PhBPCP) consisting of a strong emission fluorophore with benzoxazole and cyano groups is designed and synthesized to realize dual responses to volatile acid and organic amine vapors. The photophysical properties and self-assembly of the said derivative in the gel phase are also studied. C12PhBPCP can gelate organic solvents and self-assemble into 1 D nanofibers in the gels. UV/Vis absorption spectral results show H-aggregate formation during gelation, which indicates strong exciton coupling between fluorophores. Both wet gel and xerogel emit strong green fluorescence because the cyano group suppresses fluorescence quenching in the self-assemblies. Moreover, the xerogel film with strong green fluorescence can be used as a dual chemosensor for quantitative detection of volatile acid and organic amine vapors with fast response times and low detection limits owing to its large surface area and amplified fluorescence quenching. The detection limits are 796 ppt and 25 ppb for gaseous aniline and trifluoroacetic acid (TFA), respectively. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Binding selectivity of vitamin K3 based chemosensors towards nickel(II) and copper(II) metal ions

    Science.gov (United States)

    Patil, Amit; Lande, Dipali N.; Nalkar, Archana; Gejji, Shridhar P.; Chakrovorty, Debamitra; Gonnade, Rajesh; Moniz, Tânia; Rangel, Maria; Pereira, Eulália; Salunke-Gawali, Sunita

    2017-09-01

    The vitamin K3 derivatives 2-methyl-3-[(pyridin-2-ylmethyl)-amino]-1,4-naphthoquinone (M-1), 2-methyl-3-[(pyridin-2-ylethyl)-amino]-1,4-naphthoquinone (M-2), 2-methyl-3-((2-(thiophen-2-yl)methyl)amino)naphthalene-1,4-dione (M-3) and 2-methyl-3-((2-(thiophen-2-yl)ethyl)amino)naphthalene-1,4-dione (M-4) have been synthesized, characterized and studied for their chemosensor abilities towards transition metal ions. Crystal structures of M-1 to M-4 revealed a variety of Nsbnd H⋯O, Csbnd H⋯O, Csbnd H⋯π and π⋯π interactions. Minor variations in such interactions by chemical stimuli such as metal ions, results in change in color that can be visualized by naked eyes. It has been shown that electronic structure and 1H NMR, vibrational as well as electronic spectra from the density functional theory agree well with the experiments. The metal ion binding in ethanol, ethanol-water and in mild base triethylamine brings forth recognizing ability of M-1 toward Ni2+ whereas M-2 exhibits large sensing ability for Cu2+ ion. Interestingly M-1 display varying metal ion binding specificity in different solvents with the association constant in ethanol being 11,786 M-1 for Ni2+ compared to 9462 M-1 for the Cu2+. A reversal in preferential binding of M-2 with the respective association constants being 4190 M-1 and 6370 M-1 is discernible.

  15. Characterization of quinoxolinol salen ligands as selective ligands for chemosensors for uranium

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, Michael A. II; Kerns, Spencer A.; Gorden, Anne E.V. [Department of Chemistry and Biochemistry, Auburn University, Auburn, AL (United States)

    2015-12-15

    Quinoxalinol salen ligands have been characterized as selective ligands for the rapid identification of uranyl. The absorption maximum of ligand 1 presented a hypsochromic (blue) shift with the addition of UO{sub 2}{sup 2+} (as the acetate salt), and a bathochromic (red) shift in the presence of Cu{sup 2+} or Co{sup 2+} acetate salts, resulting in distinct, visible color changes for all three metal ions. The absorption maximum of ligand 2 was not observed to change with the addition of UO{sub 2}{sup 2+}; however, it does present a bathochromic shift with the addition of Cu{sup 2+}, and a hypsochromic shift with Co{sup 2+} added. Using TDDFT calculations, it was demonstrated that the hypsochromic shift for UO{sub 2}{sup 2+} ion complexation with ligand 1 is caused by a ligand-to-metal charge transfer, while the bathochromic shift observed with Cu{sup 2+} ion addition was caused by a metal-to-ligand charge transfer. Finally, it was found that the addition of Cu{sup 2+} (as metal salts) to either ligand resulted in rapid, complete quenching of the ligand fluorescence. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Quantifying linguistic coordination

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Tylén, Kristian

    task (Bahrami et al 2010, Fusaroli et al. 2012) we extend to linguistic coordination dynamical measures of recurrence employed in the analysis of sensorimotor coordination (such as heart-rate (Konvalinka et al 2011), postural sway (Shockley 2005) and eye-movements (Dale, Richardson and Kirkham 2012...... of linguistic coordination and their effects at a fine-degree....

  17. An Amidochlorin-Based Colorimetric Fluorescent Probe for Selective Cu2+ Detection

    Directory of Open Access Journals (Sweden)

    Wenting Li

    2016-01-01

    Full Text Available The design and synthesis of selective and sensitive chemosensors for the quantification of environmentally and biologically important ionic species has attracted widespread attention. Amidochlorin p6 (ACP; an effective colorimetric and fluorescent probe for copper ions (Cu2+ in aqueous solution derived from methyl pheophorbide-a (MPa was designed and synthesized. A remarkable color change from pale yellow to blue was easily observed by the naked eye upon addition of Cu2+; and a fluorescence quenching was also determined. The research of fluorescent quenching of ACP-Cu2+ complexation showed the detection limit was 7.5 × 10−8 mol/L; which suggested that ACP can act as a high sensitive probe for Cu2+ and can be used to quantitatively detect low levels of Cu2+ in aqueous solution. In aqueous solution the probe exhibits excellent selectivity and sensitivity toward Cu2+ ions over other metal ions (M = Zn2+; Ni2+; Ba2+; Ag+; Co2+; Na+; K+; Mg2+; Cd2+; Pb2+; Mn2+; Fe3+; and Ca2+. The obvious change from pale yellow to blue upon the addition of Cu2+ could make it a suitable “naked eye” indicator for Cu2+.

  18. Movement coordination during conversation.

    Directory of Open Access Journals (Sweden)

    Nida Latif

    Full Text Available Behavioral coordination and synchrony contribute to a common biological mechanism that maintains communication, cooperation and bonding within many social species, such as primates and birds. Similarly, human language and social systems may also be attuned to coordination to facilitate communication and the formation of relationships. Gross similarities in movement patterns and convergence in the acoustic properties of speech have already been demonstrated between interacting individuals. In the present studies, we investigated how coordinated movements contribute to observers' perception of affiliation (friends vs. strangers between two conversing individuals. We used novel computational methods to quantify motor coordination and demonstrated that individuals familiar with each other coordinated their movements more frequently. Observers used coordination to judge affiliation between conversing pairs but only when the perceptual stimuli were restricted to head and face regions. These results suggest that observed movement coordination in humans might contribute to perceptual decisions based on availability of information to perceivers.

  19. Introduction to fluorescence microscopy.

    Science.gov (United States)

    Ghiran, Ionita C

    2011-01-01

    This chapter is an overview of basic principles of fluorescence microscopy, including a brief history on the invention of this type of microscopy. The chapter highlights important points related to properties of fluorochromes, resolution in fluorescence microscopy, phase contrast and fluorescence, fluorescence filters, construction of a fluorescence microscope, and tips on the correct use of this equipment.

  20. Structurally tuned benzo[h]chromene derivative as Pb{sup 2+} selective ‘turn-on’ fluorescence sensor for living cell imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Sougata; Rani Koner, Rik; Kumar, Sunil [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175001, H.P (India); Mathew, Jomon [Schulich Faculty of Chemistry and the Lise Meitner Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa (Israel); Roy, Anindita [Department of Microbiology, MUC Women’s College, Burdwan, West Bengal (India); Kanti Mukhopadhyay, Subhra [Department of Microbiology, Burdwan University, Burdwan, West Bengal (India); Nandi, Chayan K., E-mail: chayan@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175001, H.P (India); Ghosh, Subrata, E-mail: subrata@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175001, H.P (India)

    2013-11-15

    A benzo[h]chromene derivative, 2-amino-4-phenyl-4H-benzo[h]chromene-3-carbonitrile 1, has been utilized as ‘Turn On’ fluorescence chemosensor for the selective detection of Pb{sup 2+}. The title compound 1 was synthesized in one step using a multicomponent condensation reaction (MCR), and characterized using various spectroscopic techniques. The selectivity was tested over a range of 17 different metal and non-metal ions. Compound 1 was found to be weak fluorescent (Φ{sub 1}=0.06) because of photoinduced electron transfer (PET). The presence of 2 equiv of Pb{sup 2+} showed a significant increase in fluorescence quantum yield (Φ{sub 1−Pb{sup 2}{sup +}}=0.132). A change in weak blue emission of 1 to a glowing green emission along with a prominent red shift (26 nm) in emission band was observed upon addition of Pb{sup 2+} to a methanolic solution of 1. The complexation of 1 with Pb{sup 2+} was proved by mass spectroscopy and NMR studies. Some of our experimental findings have been supported by theoretical studies. Compound 1 was found to be easily permeable to living cells without causing any harm and ultimately was used to detect effectively Pb{sup 2+} in living system. -- Highlights: • Benzo[h]chromene derivative (1) as fluorogenic chemosensor for Pb{sup 2+}. • One-step synthesis of the sensor using multicomponent condensation reaction. • The sensor follows a ‘turn-on’ mechanism through CHEF. • 1–Pb{sup 2+} complex was characterized by various spectroscopic techniques. • The probe can detect Pb{sup 2+} in living cells.

  1. Fluorescence detection: SPIE volume 743

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, E.R.

    1987-01-01

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics.

  2. Two emissive-magnetic composite platforms for Hg(II) sensing and removal: The combination of magnetic core, silica molecular sieve and rhodamine chemosensors.

    Science.gov (United States)

    Mao, Hanping; Liu, Zhongshou

    2018-01-15

    In this paper, a composite sensing platform for Hg(II) optical sensing and removal was designed and reported. A core-shell structure was adopted, using magnetic Fe3O4 nanoparticles as the core, silica molecular sieve MCM-41 as the shell, respectively. Two rhodamine derivatives were synthesized as chemosensor and covalently immobilized into MCM-41 tunnels. Corresponding composite samples were characterized with SEM/TEM images, XRD analysis, IR spectra, thermogravimetry and N2 adsorption/desorption analysis, which confirmed their core-shell structure. Their emission was increased by Hg(II), showing emission turn on effect. High selectivity, linear working curves and recyclability were obtained from these composite samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A squaraine-based colorimetric and F(-) dependent chemosensor for recyclable CO2 gas detection: highly sensitive off-on-off response.

    Science.gov (United States)

    Xia, Guomin; Liu, Yang; Ye, Benfei; Sun, Jianqi; Wang, Hongming

    2015-09-18

    An unsymmetrical squaraine-based chemosensor SH2 has been synthesized, and its sensing behavior towards CO2 gas was described in detail by UV-vis and (1)H NMR spectroscopies in DMSO. The results indicated that the extremely sensitive "naked-eye" CO2 gas detection can be operated in the presence of excess [Bu4N]F (TBAF) and the sensor is easy to recycle. These properties enable SH2 to act as a CO2 and F(-) controlled "OFF-ON-OFF" switch. Combining theoretical analyses, a plausible sensing mechanism was proposed to illustrate how the receptor SH2 works as a CO2 sensitive and selective colorimetric probe in the present system.

  4. Highly sensitive detection of nitroaromatic explosives using an electrospun nanofibrous sensor based on a novel fluorescent conjugated polymer.

    Science.gov (United States)

    Long, Yuanyuan; Chen, Haibo; Wang, Huaming; Peng, Zhou; Yang, Yufei; Zhang, Guoqing; Li, Na; Liu, Feng; Pei, Jian

    2012-09-26

    An electrospun nanofibrous explosive sensor was first constructed based on a newly developed fluorescent conjugated polymer P containing heteroatom polycyclic units. Electrospinning by doping polymer P as a fluorescent probe in a polystyrene supporting matrix afforded a fluorescence nanofibrous film with unique porous structures, and effectively avoided the aggregation of polymer P. The novel explosive sensor exhibited stable fluorescence property, satisfactory reversibility with less than 5% loss of signal intensity after four quenching-regeneration cycles, and good reproducibility among three batches with a relative standard deviation of 2.8%. Such fabricated sensor also showed remarkable sensitivity toward a series of trace nitroaromatic explosive vapors, including picric acid (parts-per-trillion level) and 2,4,6-trinitrotoluene vapor (parts-per-billion level), as well as good selectivity with less than 10% response to typical interferents. Therefore, the present strategy extends the application of different kinds of conjugated polymers for the construction of optical chemosensors. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A simple fluorescent probe for the fast sequential detection of copper and biothiols based on a benzothiazole derivative

    Science.gov (United States)

    Shen, Youming; Zhang, Xiangyang; Zhang, Chunxiang; Zhang, Youyu; Jin, Junling; Li, Haitao

    2018-02-01

    A simple benzothiazole fluorescent chemosensor was developed for the fast sequential detection of Cu2 + and biothiols through modulating the excited-state intramolecular proton transfer (ESIPT) process. The compound 1 exhibits highly selective and sensitive fluorescence ;on-off; recognition to Cu2 + with a 1:1 binding stoichiometry by ESIPT hinder. The in situ generated 1-Cu2 + complex can serve as an ;on-off; fluorescent probe for high selectivity toward biothiols via Cu2 + displacement approach, which exerts ESIPT recovery. It is worth pointing out that the 1-Cu2 + complex shows faster for cysteins (within 1 min) than other biothiols such as homocysteine (25 min) and glutathione (25 min). Moreover, the compound 1 displays 160 nm Stoke-shift for reversibly monitoring Cu2 + and biothiols. In addition, the probe is successfully used for fluorescent cellular imaging. This strategy via modulation the ESIPT state has been used for determination of Cu2 + and Cys with satisfactory results, which further demonstrates its value of practical applications.

  6. Synthesis, characterization and application of poly(acrylamide-co-methylenbisacrylamide) nanocomposite as a colorimetric chemosensor for visual detection of trace levels of Hg and Pb ions

    Energy Technology Data Exchange (ETDEWEB)

    Sedghi, Roya, E-mail: r_sedghi@sbu.ac.ir; Heidari, Bahareh; Behbahani, Mohammad

    2015-03-21

    Highlights: • Poly(acrylamide-co-methylenbisacrylamide) nanocomposite. • Colorimetric chemosensor. • Determination of trace levels of Hg and Pb ions. • Environmental samples. - Abstract: In this study, a new colorimetric chemosensor based on TiO{sub 2}/poly(acrylamide-co-methylenbisacrylamide) nanocomposites was designed for determination of mercury and lead ions at trace levels in environmental samples. The removal and preconcentration of lead and mercury ions on the sorbent was achieved due to sharing an electron pair of N and O groups of polymer chains with the mentioned heavy metal ions. The hydrogel sensor was designed by surface modification of a synthesized TiO{sub 2} nanoparticles using methacryloxypropyltrimethoxysilan (MAPTMS), which provided a reactive C=C bond that polymerized the acrylamide and methylenbisacrylamide. The sorbent was characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), EDS analysis and Fourier transform in frared (FT-IR) spectrometer. This nanostructured composite with polymer shell was developed as a sensitive and selective sorbent for adsorption of mercury and lead ions from aqueous solution at optimized condition. This method involves two-steps: (1) preconcentration of mercury and lead ions by the synthesized sorbent and (2) its selective monitoring of the target ions by complexation with dithizone (DZ). The color of the sorbent in the absence and presence of mercury and lead ions shifts from white to violet and red, respectively. The detection limit of the synthesized nanochemosensor for mercury and lead ions was 1 and 10 μg L{sup −1}, respectively. The method was successfully applied for trace detection of mercury and lead ions in tap, river, and sea water samples.

  7. Coordinate measuring machines

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceabilit...

  8. Coordination failure caused by sunspots

    DEFF Research Database (Denmark)

    Beugnot, Julie; Gürgüç, Zeynep; Øvlisen, Frederik Roose

    2012-01-01

    In a coordination game with Pareto-ranked equilibria, we study whether a sunspot can lead to either coordination on an inferior equilibrium (mis-coordination) or to out-of equilibrium behavior (dis-coordination). While much of the literature searches for mechanisms to attain coordination on the e......In a coordination game with Pareto-ranked equilibria, we study whether a sunspot can lead to either coordination on an inferior equilibrium (mis-coordination) or to out-of equilibrium behavior (dis-coordination). While much of the literature searches for mechanisms to attain coordination...

  9. Chemically induced fluorescence switching of carbon-dots and its multiple logic gate implementation.

    Science.gov (United States)

    Dhenadhayalan, Namasivayam; Lin, King-Chuen

    2015-05-06

    Investigations were carried out on the carbon-dots (C-dots) based fluorescent off - on (Fe(3 + )- S2O3(2-)) and on - off (Zn(2 + )- PO4(3-)) sensors for the detection of metal ions and anions. The sensor system exhibits excellent selectivity and sensitivity towards the detection of biologically important Fe(3 + ), Zn(2 + ) metal ions and S2O3(2-), PO4(3-) anions. It was found that the functional group on the C-dots surface plays crucial role in metal ions and anions detection. Inspired by the sensing results, we demonstrate C-dots based molecular logic gates operation using metal ions and anions as the chemical input. Herein, YES, NOT, OR, XOR and IMPLICATION (IMP) logic gates were constructed based on the selection of metal ions and anions as inputs. This carbon-dots sensor can be utilized as various logic gates at the molecular level and it will show better applicability for the next generation of molecular logic gates. Their promising properties of C-dots may open up a new paradigm for establishing the chemical logic gates via fluorescent chemosensors.

  10. Fundamentals of fluorescence and fluorescence microscopy.

    Science.gov (United States)

    Wolf, David E

    2013-01-01

    This chapter discusses the fundamental physics of fluorescence. The application of fluorescence to microscopy represents an important transition in the development of microscopy, particularly as it applies to biology. It enables quantitating the amounts of specific molecules within a cell, determining whether molecules are complexing on a molecular level, measuring changes in ionic concentrations within cells and organelles, and measuring molecular dynamics. This chapter also discusses the issues important to quantitative measurement of fluorescence and focuses on four of quantitative measurements of fluorescence--boxcar-gated detection, streak cameras, photon correlation, and phase modulation. Although quantitative measurement presents many pitfalls to the beginner, it also presents significant opportunities to one skilled in the art. This chapter also examines how fluorescence is measured in the steady state and time domain and how fluorescence is applied in the modern epifluorescence microscope. Copyright © 2007 Elsevier Inc. All rights reserved.

  11. The curvature coordinate system

    DEFF Research Database (Denmark)

    Almegaard, Henrik

    2007-01-01

    The paper describes a concept for a curvature coordinate system on regular curved surfaces from which faceted surfaces with plane quadrangular facets can be designed. The lines of curvature are used as parametric lines for the curvature coordinate system on the surface. A new conjugate set of lines......, called middle curvature lines, is introduced. These lines define the curvature coordinate system. Using the curvature coordinate system, the surface can be conformally mapped on the plane. In this mapping, elliptic sections are mapped as circles, and hyperbolic sections are mapped as equilateral...... hyperbolas. This means that when a plane orthogonal system of curves for which the vertices in a mesh always lie on a circle is mapped on a surface with positive Gaussian curvature using inverse mapping, and the mapped vertices are connected by straight lines, this network will form a faceted surface...

  12. Environmental Compliance Issue Coordination

    Science.gov (United States)

    An order to establish the Department of Energy (DOE) requirements for coordination of significant environmental compliance issues to ensure timely development and consistent application of Departmental environmental policy and guidance

  13. Supercritical Airfoil Coordinates

    Data.gov (United States)

    National Aeronautics and Space Administration — Rectangular Supercritical Wing (Ricketts) - design and measured locations are provided in an Excel file RSW_airfoil_coordinates_ricketts.xls . One sheet is with Non...

  14. A highly selective and ratiometric fluorescent probe for cyanide by rationally altering the susceptible H-atom.

    Science.gov (United States)

    Hao, Yuanqiang; Nguyen, Khac Hong; Zhang, Yintang; Zhang, Guan; Fan, Shengnan; Li, Fen; Guo, Chao; Lu, Yuanyuan; Song, Xiaoqing; Qu, Peng; Liu, You-Nian; Xu, Maotian

    2018-01-01

    A highly selective and ratiometric fluorescent probe for cyanide was rationally designed and synthesized. The probe comprises a fluorophore unit of naphthalimide and a CN- acceptor of methylated trifluoroacetamide group. For these previous reported trifluoroacetamide derivative-based cyanide chemosensors, the H-atom of amide adjacent to trifluoroacetyl group is susceptible to be attacked by various anions (CN- itself, F-, AcO-, et al.) and even the solvent molecule, which resulted in the bewildered reaction mechanism and poor selectivity of the assay. In this work, the susceptible H-atom of trifluoroacetamide was artfully substituted by alkyl group. Thus a highly specific fluorescent probe was developed for cyanide sensing. Upon the nucleophilic addition of cyanide anion to the carbonyl of trifluoroacetamide moiety of the probe, the ICT process of the probe was significantly enhanced and leading to a remarkable red shift in both absorption and emission spectra of the probe. This fluorescent assay showed a linear range of 1.0-80.0µM and a LOD (limit of detection) of 0.23µM. All the investigated interference have no influence on the sensing behavior of the probe toward cyanide. Moreover, by coating on TLC plate, the probe can be utilized for practical detection of trace cyanide in water samples. Copyright © 2017. Published by Elsevier B.V.

  15. Metric Coordinate Systems

    OpenAIRE

    Calcaterra, Craig; Boldt, Axel; Green, Michael; Bleecker, David

    2002-01-01

    Coordinate systems are defined on general metric spaces with the purpose of generalizing vector fields on a manifold. Conversion formulae are available between metric and Cartesian coordinates on a Hilbert space. Nagumo's Invariance Theorem is invoked to prove the analogue of the classical Cauchy-Lipschitz Theorem for vector fields on a locally compact coordinatized space. A metric space version of Nagumo's Theorem is one consequence. Examples are given throughout.

  16. N-phenyl-1-naphthylamine/β-cyclodextrin inclusion complex as a new fluorescent probe for rapid and visual detection of Pd2+

    Science.gov (United States)

    Maniyazagan, Munisamy; Mohandoss, Sonaimuthu; Sivakumar, Krishnamoorthy; Stalin, Thambusamy

    2014-12-01

    Inclusion complex between N-phenyl-1-naphthylamine (NPN) and β-cyclodextrin (β-CD) was studied by FT-IR, 1H and 2D NMR, XRD, FT-Raman, SEM and DSC techniques. The formation of 1:1 stoichiometric inclusion complex of NPN with β-CD was proposed based on the Nuclear magnetic resonance spectroscopy and Molecular docking study. The molecular encapsulation of host-guest inclusion complex based on simple chemosensor has high selectivity and sensitivity for the determination of Pd2+ ion. Host-guest inclusion complex as a spectroscopic probe is used for the detection of transition metal cation Pd2+. Coordination of this Pd2+ with (NPN/β-CD) inclusion complex exhibited a noticeable color change in the solution state it used for naked-eye detection.

  17. N-phenyl-1-naphthylamine/β-cyclodextrin inclusion complex as a new fluorescent probe for rapid and visual detection of Pd(2+).

    Science.gov (United States)

    Maniyazagan, Munisamy; Mohandoss, Sonaimuthu; Sivakumar, Krishnamoorthy; Stalin, Thambusamy

    2014-12-10

    Inclusion complex between N-phenyl-1-naphthylamine (NPN) and β-cyclodextrin (β-CD) was studied by FT-IR, (1)H and 2D NMR, XRD, FT-Raman, SEM and DSC techniques. The formation of 1:1 stoichiometric inclusion complex of NPN with β-CD was proposed based on the Nuclear magnetic resonance spectroscopy and Molecular docking study. The molecular encapsulation of host-guest inclusion complex based on simple chemosensor has high selectivity and sensitivity for the determination of Pd(2+) ion. Host-guest inclusion complex as a spectroscopic probe is used for the detection of transition metal cation Pd(2+). Coordination of this Pd(2+) with (NPN/β-CD) inclusion complex exhibited a noticeable color change in the solution state it used for naked-eye detection. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Magnetic Coordinate Systems

    Science.gov (United States)

    Laundal, K. M.; Richmond, A. D.

    2017-03-01

    Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.

  19. [Coordination and donation].

    Science.gov (United States)

    Elizalde, J; Lorente, M

    2006-01-01

    The progressive incorporation of organ transplants as a therapeutic resource resulted in organisational adaptation and overall transplant management, leading to the emergence of the figure of the transplant coordinator in the mid-1980s. In Spain, the National Organisation of Transplants (Organización Nacional de Transplantes - ONT) was created, establishing a system - called the "Spanish model" - based on a network of coordinators at three levels: national, the autonomous community and the hospital. This organisational structure is a point of reference at the world level. The prevalence of the Intensive Medicine specialisation amongst hospital transplant coordinators is remarkable. The majority of organs proceed from brain-dead patients with beating hearts and this requires the infrastructure offered by intensive care units. The functions of the coordinator can be summarised in guaranteeing a synchrony of all the elements and teams that come together in an organisational chain that has come to be called the "process of donation". Schematically, the crucial points that the hospital coordinator develops are the following: - Detection of the potential donor. - Maintenance of the donor. - Diagnosis of brain death. - Family consent. - Preparation of the hospital logistics. - Helping the relatives. - Direct involvement in the Program of Guarantee of Quality. - Person of reference in any activity related to the transplant. It would be desirable to achieve the creation of transplant coordination teams, with univocal messages, professionalism and a permanent input of the so-called "human factor", which is so necessary and also so close to the transplant world.

  20. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  1. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  2. Chemo-sensors development based on low-dimensional codoped Mn2O3-ZnO nanoparticles using flat-silver electrodes.

    Science.gov (United States)

    Rahman, Mohammed M; Gruner, George; Al-Ghamdi, Mohammed Saad; Daous, Muhammed A; Khan, Sher Bahadar; Asiri, Abdullah M

    2013-03-28

    Semiconductor doped nanostructure materials have attained considerable attention owing to their electronic, opto-electronic, para-magnetic, photo-catalysis, electro-chemical, mechanical behaviors and their potential applications in different research areas. Doped nanomaterials might be a promising owing to their high-specific surface-area, low-resistances, high-catalytic activity, attractive electro-chemical and optical properties. Nanomaterials are also scientifically significant transition metal-doped nanostructure materials owing to their extraordinary mechanical, optical, electrical, electronic, thermal, and magnetic characteristics. Recently, it has gained significant interest in manganese oxide doped-semiconductor materials in order to develop their physico-chemical behaviors and extend their efficient applications. It has not only investigated the basic of magnetism, but also has huge potential in scientific features such as magnetic materials, bio- & chemi-sensors, photo-catalysts, and absorbent nanomaterials. The chemical sensor also displays the higher-sensitivity, reproducibility, long-term stability, and enhanced electrochemical responses. The calibration plot is linear (r2 = 0.977) over the 0.1 nM to 50.0 μM 4-nitrophenol concentration ranges. The sensitivity and detection limit is ~4.6667 μA cm-2 μM-1 and ~0.83 ± 0.2 nM (at a Signal-to-Noise-Ratio, SNR of 3) respectively. To best of our knowledge, this is the first report for detection of 4-nitrophenol chemical with doped Mn2O3-ZnO NPs using easy and reliable I-V technique in short response time. As for the doped nanostructures, NPs are introduced a route to a new generation of toxic chemo-sensors, but a premeditate effort has to be applied for doped Mn2O3-ZnO NPs to be taken comprehensively for large-scale applications, and to achieve higher-potential density with accessible to individual chemo-sensors. In this report, it is also discussed the prospective utilization of Mn2O3-ZnO NPs on the basis

  3. coordination polymers derived from two different bis-pyridyl-bis-am

    Indian Academy of Sciences (India)

    Three new Ni(II) coordination polymers exhibiting different 1D and 2D framework structures have been hydrothermally ... Keywords. Metal-organic coordination polymer; crystal structure; bis-pyridyl-bis-amide ligand; fluorescence; photocatalysis ... materials for luminescence, catalysis, gas storage and separation, magnetism ...

  4. Anthracene coupled thiourea as a colorimetric sensor for F{sup −}/Cu{sup 2+} and fluorescent sensor for Hg{sup 2+}/picric acid

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy [Organic and Polymer Synthesis Laboratory, Department of Chemistry, National Institute of Technology, Tiruchirappalli-620 015 (India); Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Organic and Polymer Synthesis Laboratory, Department of Chemistry, National Institute of Technology, Tiruchirappalli-620 015 (India); Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2015-05-15

    A new dual chemosensor (Z)-2-(anthracen-9-ylmethylene)-N-phenylhydrazinecarbothioamide R1 was synthesized by incorporating a thiourea derivative as a binding unit and an anthracene group as a fluorescence signalling unit. R1 selectively binds with Cu{sup 2+} and Hg{sup 2+} ions in aqueous medium. R1 exhibits highly selective recognition towards F{sup −} ion and picric acid in organic medium. Fluorescence quenching was observed in case of R1 with Cu{sup 2+} and Hg{sup 2+} ions over commonly coexistent metal ions. Furthermore, fluorescence imaging experiments of Cu{sup 2+} and Hg{sup 2+} ions in living RAW 264.7 cells demonstrate its value of practical applications in biological systems. - Highlights: • R1 exhibited highly selective recognition towards Cu{sup 2+}, Hg{sup 2+} and F{sup −} ions. • The anion detection by R1 is further confirmed by {sup 1}H NMR titration method. • Detection of Cu{sup 2+} and Hg{sup 2+} ion in the living cell was achieved using fluorescence microscope. • R1 selectively sense picric acid over other nitroaromatics.

  5. Coordinating Interactions: The Event Coordination Notation

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    The purpose of a domain model is to concisely capture the concepts of an application’s domain, and their relation among each other. Even though the main purpose of domain models is not on implementing the application, major parts of an application can be generated from the application’s domain...... on a much more technical level. The Event Coordination Notation (ECNO) allows modelling the behaviour of an application on a high level of abstraction that is closer to the application’s domain than to the software realizing it. Still, these models contain all necessary details for actually executing...... models fully automatically with today’s technologies. The focus of today’s code generation technologies, however, is mostly on the structural aspects of the domain; the domain’s behaviour is often not modelled at all, or implemented manually based on some informal models, or the behaviour is modelled...

  6. Introduction to Coordination Chemistry

    CERN Document Server

    Lawrance, Geoffrey Alan

    2010-01-01

    Introduction to Coordination Chemistry examines and explains how metals and molecules that bind as ligands interact, and the consequences of this assembly process. This book describes the chemical and physical properties and behavior of the complex assemblies that form, and applications that may arise as a result of these properties. Coordination complexes are an important but often hidden part of our world?even part of us?and what they do is probed in this book. This book distills the essence of this topic for undergraduate students and for research scientists.

  7. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    C -1 D FLUORESCENT LAMP SPECIFICATION SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . D -1 E LED WAVES’ LED ...friendly products, advances in efficiency, and lower production costs for lamps . The conversion of fluorescent bulbs to LED technology has many benefits...repeatedly turned on and off. (5) LEDs can be used in existing fluorescent lighting fixtures using LED retrofit kits or replacement lamps . (6

  8. Characterization and application studies of ProxyPhos, a chemosensor for the detection of proximally phosphorylated peptides and proteins in aqueous solutions.

    Science.gov (United States)

    Kraskouskaya, D; Cabral, A D; Fong, R; Bancerz, M; Toutah, K; Rosa, D; Gardiner, J E; de Araujo, E D; Duodu, E; Armstrong, D; Fekl, U; Gunning, P T

    2017-06-26

    Proximal phosphorylation on proteins appears to have functional significance and has been associated with several diseases, including Alzheimer's and cancer. While much remains to be learned about the role of proximal phosphorylation in biological systems, no simple and/or affordable technique is available for its detection. To this end, we have previously developed a ProxyPhos chemosensor, which detects proximally phosphorylated peptides and proteins over mono- and non-phosphorylated motifs in aqueous solutions. In this follow-up work, we performed extensive characterization of peptide and protein ProxyPhos assay conditions to achieve enhanced detection, and further explored the selectivity of ProxyPhos, and its potential off-targets. As a result of characterization studies, selective sensing of proximally phosphorylated over mono-phosphorylated peptides and proteins was achieved. Moreover, studies demonstrated that ProxyPhos was compatible with the detection of all commonly phosphorylated residues (i.e. tyrosine, serine and threonine residues). Under optimized conditions, ProxyPhos efficiently discriminated between peptides derived from the activated (proximally phosphorylated, disease-relevant) and inactive (mono-phosphorylated) forms of JAK2, SYK and MAPK1 kinases. In addition, ProxyPhos can be used to probe phosphatase activity on peptides and proteins via detecting changes in proximal phosphorylation, demonstrating immediate utility of this chemosensing system.

  9. Rational design of a novel azoimine appended maleonitrile-based Salen chemosensor for rapid naked-eye detection of copper(II) ion in aqueous media.

    Science.gov (United States)

    Rezaeian, Khatereh; Khanmohammadi, Hamid; Arab, Vajihe

    2015-12-05

    Achieving specific selectivity and high sensitivity for the colorimetric recognition of copper(II) ions in aqueous media over a complex background of potentially competing metal ions is inherently challenging in sensor development. Thus, a novel azo-azomethine receptor (L) based on the combination of 2-amino-3-(5-bromo-2-hydroxybenzylamino)maleonitrile and azo-coupled salicylaldehyde scaffold has been designed and synthesized for the naked-eye and rapid detection of Cu(2+) ion at trace level in a wide pH range. Accordingly, the devised chemosensor distinguished Cu(2+) from other metal ions by distinct color change from light yellow to light brown without any expensive equipment. The binding stoichiometry between Cu(2+) and L has been investigated using Job's plot and MALDI-TOF mass analysis. Remarkably, the current sensor can detect Cu(2+) ions even at 1.07 μM level, which is lower than the World Health Organization (WHO) permissible level (30 μM) in drinking water. Furthermore, sensor L was successfully utilized in the preparation of test strips for the detection of copper(II) ions from aqueous environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Polymeric coordination compounds

    Indian Academy of Sciences (India)

    Administrator

    Metal coordination polymers with one- and two-dimensional structures are of current interest due to their possible relevance to material science 1. In continuation of our previous studies 2,3, several new polymeric compounds are reported here. Among the complexes of silver with aminomethyl pyridine (amp) ...

  11. Coordination Games on Graphs

    NARCIS (Netherlands)

    K.R. Apt (Krzysztof); M.M. Rahn (Mona); G. Schäfer (Guido); S.E. Simon (Sunil)

    2014-01-01

    htmlabstractWe introduce natural strategic games on graphs, which capture the idea of coordination in a local setting.We show that these games have an exact potential and have strong equilibria when the graph is a pseudoforest. We also exhibit some other classes of games for which a strong

  12. Dimensions of Organizational Coordination

    DEFF Research Database (Denmark)

    Jensen, Andreas Schmidt; Aldewereld, Huib; Dignum, Virginia

    2013-01-01

    be supported to include organizational objectives and constraints into their reasoning processes by considering two alternatives: agent reasoning and middleware regulation. We show how agents can use an organizational specification to achieve organizational objectives by delegating and coordinating...... their activities with other agents in the society, using the GOAL agent programming language and the OperA organizational model....

  13. Coordination Compounds in Biology

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 6. Coordination Compounds in Biology - The Chemistry of Vitamin B12 and Model Compounds. K Hussian Reddy. General Article Volume 4 Issue 6 June 1999 pp 67-77 ...

  14. Recursive Advice for Coordination

    DEFF Research Database (Denmark)

    Terepeta, Michal Tomasz; Nielson, Hanne Riis; Nielson, Flemming

    2012-01-01

    Aspect-oriented programming is a programming paradigm that is often praised for the ability to create modular software and separate cross-cutting concerns. Recently aspects have been also considered in the context of coordination languages, offering similar advantages. However, introducing aspects...

  15. Coordination Games on Graphs

    NARCIS (Netherlands)

    Apt, K.R.; Rahn, M.; Schäfer, G.; Simon, S.; Liu, T.-Y.; Qi, Q.; Ye, Y.

    2014-01-01

    We introduce natural strategic games on graphs, which capture the idea of coordination in a local setting. We show that these games have an exact potential and have strong equilibria when the graph is a pseudoforest. We also exhibit some other classes of graphs for which a strong equilibrium exists.

  16. Coordinating Supplemental Reading Instruction

    Science.gov (United States)

    Deeney, Theresa A.

    2008-01-01

    Although supplemental reading services are meant to improve reading achievement of struggling readers and students with reading disabilities, without concerted effort to ensure communication and coordination with in-school instruction, they may fall short of their desired mark. To promote learning, it is critical that any services provided outside…

  17. In vivo quantitative visualization of hypochlorous acid in the liver using a novel selective two-photon fluorescent probe

    Science.gov (United States)

    Wang, Haolu; Jayachandran, Aparna; Gravot, Germain; Liang, Xiaowen; Thorling, Camilla A.; Zhang, Run; Liu, Xin; Roberts, Michael S.

    2016-11-01

    Hypochlorous acid (HOCl) plays a vital role in physiological events and diseases. During hepatic ischemia-reperfusion (I/R) injury, HOCl is generated by neutrophils and diffuses into hepatocytes, causing oxidant stress-mediated injury. Although many probes have been developed to detect HOCl, most were difficult to be distinguished from endogenous fluorophores in intravital imaging and only can be employed under one-photon microscopy. A novel iridium(III) complex-based ferrocene dual-signaling chemosensor (Ir-Fc) was designed and synthesized. Ir-Fc exhibited a strong positive fluorescent response only in the presence of HOCl, whereas negligible fluorescent signals were observed upon the additions of other reactive oxygen/nitrogen species and metal ions. There was a good linear relationship between probe responsive fluorescent intensity and HOCl concentration. Ir-Fc was then intravenously injected into BALB/c mice at the final concentration of 50 μM and the mouse livers were imaged using multiphoton microscopy (MPM). In the I/R liver, reduced autofluorescence was detected by MPM, indicating the hepatocyte necrosis. Remarkable enhancement of red fluorescence was observed in hepatocytes with decreased autofluorescence, indicating the reaction of Ir-Fc with endogenous HOCl molecules. The cellular concentration of HOCl was first calculated based on the intensity of MPM images. No obvious toxic effects were observed in histological examination of major organs after Ir-Fc injection. In summary, Ir-Fc has low cytotoxicity, high specificity to HOCl, and rapid "off-on" fluorescence. It is suitable for dynamic quantitatively monitoring HOCl generation using MPM at the cellular level. This technique can be readily extended to examination of liver diseases and injury.

  18. What is Coordinated in Bimanual Coordination?

    Science.gov (United States)

    Mechsner, Franz; Prinz, Wolfgang

    In periodic bimanual movements there is a characteristic spontaneous tendency towards mirror-symmetry. This phenomenon has widely been interpreted as a tendency towards co-activation of homologous muscles, possibly originating in motoric neuronal structures. The experiments reported here provide evidence contrary to this common claim. The symmetry tendency in bimanual abductive/adductive finger oscillation as well as in bimanual multi-finger tapping is actually towards spatial, perceptual symmetry, without regard to the muscles and thus to the motor commands involved. It is hypothesized that, as a rule, spontaneous coordination phenomena of this kind are purely perceptual-cognitive in nature. Moreover, in the case of a bimanual circling paradigm, the reported findings reveal that highly complex, even 'impossible' movements can easily be performed if, rather than the bodily movements themselves, simple sensory consequences are controlled. It is suggested that voluntary movements are organized by representing and controlling their perceptual goals or anticipated effects, whereas the corresponding motor activity of sometimes high formal complexity is rather spontaneously and flexibly tuned in service of these effects.

  19. Novel Magnet and Thermoresponsive Chemosensory Electrospinning Fluorescent Nanofibers and Their Sensing Capability for Metal Ions

    Directory of Open Access Journals (Sweden)

    Fang-Cheng Liang

    2017-04-01

    Full Text Available Novel multifunctional switchable chemosensors based on fluorescent electrospun (ES nanofibers with sensitivity toward magnetism, temperature, and mercury ions (Hg2+ were prepared using blends of poly(N-isopropylacrylamide-co-(N-methylolacrylamide-co-(Acrylic acid, the fluorescent probe 1-benzoyl-3-[2-(2-allyl-1,3-dioxo-2,3-dihydro-1Hbenzo[de]isoquinolin-6-ylamino-ethyl]-thiourea (BNPTU, and magnetite nanoparticles (NPs, and a single-capillary spinneret. The moieties of N-isopropylacrylamide, N-methylolacrylamide, acrylic acid, BNPTU, and Iron oxide (Fe3O4 NPs were designed to provide thermoresponsiveness, chemical cross-linking, Fe3O4 NPs dispersion, Hg2+ sensing, and magnetism, respectively. The prepared nanofibers exhibited ultrasensitivity to Hg2+ (as low as 10−3 M because of an 80-nm blueshift of the emission maximum (from green to blue and 1.6-fold enhancement of the emission intensity, as well as substantial volume (or hydrophilic to hydrophobic changes between 30 and 60 °C, attributed to the low critical solution temperature of the thermoresponsive N-isopropylacrylamide moiety. Such temperature-dependent variations in the presence of Hg2+ engendered distinct on–off switching of photoluminescence. The magnetic ES nanofibers can be collected using a magnet rather than being extracted through alternative methods. The results indicate that the prepared multifunctional fluorescent ES nanofibrous membranes can be used as naked eye sensors and have the potential for application in multifunctional environmental sensing devices for detecting metal ions, temperature, and magnetism as well as for water purification sensing filters.

  20. A Turn-On Fluorescent Sensor for Selective and Sensitive Detection of Alkaline Phosphatase Activity with Gold Nanoclusters Based on Inner Filter Effect.

    Science.gov (United States)

    Liu, Haijian; Li, Ming; Xia, Yining; Ren, Xueqin

    2017-01-11

    In this work, a novel approach for simple and sensitive determination of alkaline phosphatase (ALP) is developed on the basis of an inner filter effect of p-nitrophenylphosphate (PNPP) on the fluorescence of gold nanoclusters (AuNCs). AuNCs with a high quantum yield of 12% were synthesized by one-pot strategy and were directly applied as fluorescent substance. When AuNCs were mixed with PNPP, the fluorescence of the AuNCs was remarkably quenched or was decreased via the inner filter effect since the absorption spectrum of PNPP overlaps well with the excitation spectrum of the AuNCs. While in the presence of ALP, PNPP was catalytically hydrolyzed into p-nitrophenol, which has different absorption characteristics from those of PNPP, resulting in the recovery of the AuNCs fluorescence. Thus, a novel "turn-on" fluorescent sensor for detecting ALP was established with a detection limit as low as 0.002 U/L (signal-to-noise ratio of 3). The turn-on fluorescent sensor exhibits many merits such as high sensitivity, excellent selectivity, and high signal output because of the low background signals. In addition, the developed sensing method was successfully applied to investigate ALP inhibitors and ALP determination in serum samples. A good linear relationship was obtained in the range from 0.02 to 50 U/L, and satisfactory recoveries at four spiking levels of ALP ranged from 95% to 106% with precision below 5%. The very simple sensing approach proposed here should promote the development of fluorescence turn-on chemosensors for chemo/biodetection.

  1. Coordinating Work with Groupware

    DEFF Research Database (Denmark)

    Pors, Jens Kaaber; Simonsen, Jesper

    2003-01-01

    One important goal of employing groupware is to make possible complex collaboration between geographically distributed groups. This requires a dual transformation of both technology and work practice. The challenge is to re­duce the complexity of the coordination work by successfully inte......­grating the protocol stipulating the collaboration and the ar­te­fact, in form of the groupware application, mediating the col­laboration. This paper analyses a generic groupware application that was deployed in a large financial organisation in order to support working groups distributed throughout four countries....... Using the CSCW frame­work of coordination mechanisms, we have elicited six general factors influencing the integration of the groupware application in two situations....

  2. Conformal Fermi Coordinates

    CERN Document Server

    Dai, Liang; Schmidt, Fabian

    2015-01-01

    Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable ef...

  3. Coordinating Shared Activities

    Science.gov (United States)

    Clement, Bradley

    2004-01-01

    Shared Activity Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.

  4. Global coordination: weighted voting

    Directory of Open Access Journals (Sweden)

    Jan-Erik Lane

    2014-03-01

    Full Text Available In order to halt the depletion of global ecological capital, a number of different kinds of meetings between Governments of countries in the world has been scheduled. The need for global coordination of environmental policies has become ever more obvious, supported by more and more evidence of the running down of ecological capital. But there are no formal or binding arrangements in sight, as global environmental coordination suffers from high transaction costs (qualitative voting. The CO2 equivalent emissions, resulting in global warming, are driven by the unstoppable economic expansion in the global market economy, employing mainly fossil fuel generated energy, although at the same time lifting sharply the GDP per capita of several emerging countries. Only global environmental coordination on the successful model of the World Band and the IMF (quantitative voting can stem the rising emissions numbers and stop further environmental degradation. However, the system of weighted voting in the WB and the IMF must be reformed by reducing the excessive voting power disparities, for instance by reducing all member country votes by the cube root expression.

  5. Fluorescence Live Cell Imaging

    OpenAIRE

    Ettinger, Andreas; Wittmann, Torsten

    2014-01-01

    Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein (FP) tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio and to provide a suitable environment for ...

  6. A fluorescence 'turn-on' chemodosimeter for the specific detection of Pd2+ by a rhodamine appended Schiff base and its application in live cell imaging.

    Science.gov (United States)

    Bhanja, Anup Kumar; Mishra, Snehasis; Das Saha, Krishna; Sinha, Chittaranjan

    2017-07-18

    A new rhodamine based allyl-ether Schiff base (RD) was spectroscopically characterized and used as a colorimetric and fluorimetric sensor. RD acts as turn-on highly selective fluorescent chemosensor for Pd(ii) from only a mixture of Pd(0) and Pd(ii) in the presence of 25 other cations in aqueous-acetonitrile medium. The mechanism for Pd(ii) sensing with RD involves Pd(ii)-triggered terminal (C-O)-allyl bond cleavage followed by opening of the spirolactam ring. Pd(ii) is allylphilic and the (rhodamine)O-allyl moiety selects Pd(ii) from the mixture (Pd(0) + Pd(ii)), and a fluorescence enhancement is observed. The proposal has been supported by spectroscopic data (FTIR, 1H NMR, 13C NMR, and mass spectroscopy). It is again supported by examining the Pd(ii) selectivity of an non-allylated rhodamine appended iminephenol (RD'), which failed to selectively detect Pd(ii). Hence, the presence of the allylether is mandatory in the fluorogenic motif for Pd(ii) selectivity. The limit of detection (LOD) of Pd(ii) by RD is 50 nM at pH 7.4. Fluorescence microscopic studies help in imaging the cellular uptake of Pd2+ at the nM level in the HCT116 (Human colorectal carcinoma) cell line.

  7. Off-on Fluorescent Sensor from On-off Sensor: Exploiting Silver Nanoparticles Influence on the Organic Fluorophore Fluorescence.

    Science.gov (United States)

    Hariharan, P S; Sivasubramanian, Arvind; Anthony, Savarimuthu Philip

    2014-03-01

    Turn-off fluorescence of organic fluorophore, 2-{[4-(2H-Naphtho[1,2-d][1,2,3]triazol-2-yl)-phenyl]carboxylic acid (NTPC), with metal ions (Fe(3+), Cu(2+), Pb(2+)) was converted into turn-on fluorescent sensor for biologically important Zn(2+), Cu(2+) and Fe(3+) metal ions in aqueous solution at ppb level by exploiting strong fluorescence quenching phenomena of metal nanoparticles when organic fluorophores assembled in the vicinity of metallic surface. Amino acid attached phenolic ligands (L) were used as reducing as well as functional capping agents in the synthesis of silver nanoparticles (AgNPs). The hydrogen bonding functionality of L facilitated the assembling of NTPC in the vicinity of metallic surfaces that leads to complete quenching of NTPC fluorescence. The strong and selective coordination of L with metal ions (Zn(2+), Cu(2+) and Fe(3+)) separates the NTPC from the AgNPs surface that turn-on the NTPC fluorescence. HR-TEM and absorption studies confirm the metal coordination with L and separation of NTPC from the AgNPs surface. Mn(2+) showed selective red shifting of NTPC fluorescence after 12 h with all sample. Effects of different amino acid attached phenolic ligands were explored in the metal ion sensitivity and selectivity. This approach demonstrates the multifunctional utility of metal NPs in the development of turn-on fluorescence sensor for paramagnetic heavy metal ions in aqueous solution. ᅟ

  8. Symmetric two-coordinate photodiode

    Directory of Open Access Journals (Sweden)

    Dobrovolskiy Yu. G.

    2008-12-01

    Full Text Available The two-coordinate photodiode is developed and explored on the longitudinal photoeffect, which allows to get the coordinate descriptions symmetric on the steepness and longitudinal resistance great exactness. It was shown, that the best type of the coordinate description is observed in the case of scanning by the optical probe on the central part of the photosensitive element. The ways of improvement of steepness and linear of its coordinate description were analyzed.

  9. Understanding Leadership A Coordination Theory

    OpenAIRE

    J. Foss, Nicolai

    1999-01-01

    Important aspects of leadership behavior can be rendered intelligible through a focus on coordination games. The concept of common knowledge is shown to be particularly important to understanding leadership. Thus, leaders may establish common knowledge conditions and assist the coordination of strategies in this way, or make decisions in situations where coordination problems persist in spite of common knowledge.

  10. Work Coordination Engine

    Science.gov (United States)

    Zendejas, Silvino; Bui, Tung; Bui, Bach; Malhotra, Shantanu; Chen, Fannie; Kim, Rachel; Allen, Christopher; Luong, Ivy; Chang, George; Sadaqathulla, Syed

    2009-01-01

    The Work Coordination Engine (WCE) is a Java application integrated into the Service Management Database (SMDB), which coordinates the dispatching and monitoring of a work order system. WCE de-queues work orders from SMDB and orchestrates the dispatching of work to a registered set of software worker applications distributed over a set of local, or remote, heterogeneous computing systems. WCE monitors the execution of work orders once dispatched, and accepts the results of the work order by storing to the SMDB persistent store. The software leverages the use of a relational database, Java Messaging System (JMS), and Web Services using Simple Object Access Protocol (SOAP) technologies to implement an efficient work-order dispatching mechanism capable of coordinating the work of multiple computer servers on various platforms working concurrently on different, or similar, types of data or algorithmic processing. Existing (legacy) applications can be wrapped with a proxy object so that no changes to the application are needed to make them available for integration into the work order system as "workers." WCE automatically reschedules work orders that fail to be executed by one server to a different server if available. From initiation to completion, the system manages the execution state of work orders and workers via a well-defined set of events, states, and actions. It allows for configurable work-order execution timeouts by work-order type. This innovation eliminates a current processing bottleneck by providing a highly scalable, distributed work-order system used to quickly generate products needed by the Deep Space Network (DSN) to support space flight operations. WCE is driven by asynchronous messages delivered via JMS indicating the availability of new work or workers. It runs completely unattended in support of the lights-out operations concept in the DSN.

  11. Markov stochasticity coordinates

    Science.gov (United States)

    Eliazar, Iddo

    2017-01-01

    Markov dynamics constitute one of the most fundamental models of random motion between the states of a system of interest. Markov dynamics have diverse applications in many fields of science and engineering, and are particularly applicable in the context of random motion in networks. In this paper we present a two-dimensional gauging method of the randomness of Markov dynamics. The method-termed Markov Stochasticity Coordinates-is established, discussed, and exemplified. Also, the method is tweaked to quantify the stochasticity of the first-passage-times of Markov dynamics, and the socioeconomic equality and mobility in human societies.

  12. Theoretical Studies on Two-Photon Fluorescent Hg2+ Probes Based on the Coumarin-Rhodamine System

    Directory of Open Access Journals (Sweden)

    Yujin Zhang

    2017-07-01

    Full Text Available The development of fluorescent sensors for Hg2+ has attracted much attention due to the well-known adverse effects of mercury on biological health. In the present work, the optical properties of two newly-synthesized Hg2+ chemosensors based on the coumarin-rhodamine system (named Pro1 and Pro2 were systematically investigated using time-dependent density functional theory. It is shown that Pro1 and Pro2 are effective ratiometric fluorescent Hg2+ probes, which recognize Hg2+ by Förster resonance energy transfer and through bond energy transfer mechanisms, respectively. To further understand the mechanisms of the two probes, we have developed an approach to predict the energy transfer rate between the donor and acceptor. Using this approach, it can be inferred that Pro1 has a six times higher energy transfer rate than Pro2. Thus the influence of spacer group between the donor and acceptor on the sensing performance of the probe is demonstrated. Specifically, two-photon absorption properties of these two probes are calculated. We have found that both probes show significant two-photon responses in the near-infrared light region. However, only the maximum two-photon absorption cross section of Pro1 is greatly enhanced with the presence of Hg2+, indicating that Pro1 can act as a potential two-photon excited fluorescent probe for Hg2+. The theoretical investigations would be helpful to build a relationship between the structure and the optical properties of the probes, providing information on the design of efficient two-photon fluorescent sensors that can be used for biological imaging of Hg2+ in vivo.

  13. Experiments with Fluorescent Lamps

    Science.gov (United States)

    Kraftmakher, Yaakov

    2010-10-01

    The experiments described below show the irradiance and illuminance spectra of two fluorescent lamps in relation to their color temperatures, and the efficacy in comparison to that of an incandescent lamp. Spectra of "warm white" and "cool daylight" fluorescent lamps are demonstrated.

  14. LEDs for fluorescence microscopy

    NARCIS (Netherlands)

    Young, I.T.; Garini, Y.; Dietrich, H.R.C.; Van Oel, W.; Liqui Lung, G.

    2004-01-01

    Traditional light sources for fluorescence microscopy have been mercury lamps, xenon lamps, and lasers. These sources have been essential in the development of fluorescence microscopy but each can have serious disadvantages: lack of near monochromaticity, heat generation, cost, lifetime of the light

  15. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...

  16. Multicolor, Fluorescent Supercapacitor Fiber.

    Science.gov (United States)

    Liao, Meng; Sun, Hao; Zhang, Jing; Wu, Jingxia; Xie, Songlin; Fu, Xuemei; Sun, Xuemei; Wang, Bingjie; Peng, Huisheng

    2017-10-05

    Fiber-shaped supercapacitors have attracted broad attentions from both academic and industrial communities due to the demonstrated potentials as next-generation power modules. However, it is important while remains challenging to develop dark-environment identifiable supercapacitor fibers for enhancement on operation convenience and security in nighttime applications. Herein, a novel family of colorful fluorescent supercapacitor fibers has been produced from aligned multi-walled carbon nanotube sheets. Fluorescent dye particles are introduced and stably anchored on the surfaces of aligned multi-walled carbon nanotubes to prepare hybrid fiber electrodes with a broad range of colors from red to purple. The fluorescent component in the dye introduces fluorescent indication capability to the fiber, which is particularly promising for flexible and wearable devices applied in dark environment. In addition, the colorful fluorescent supercapacitor fibers also maintain high electrochemical performance under cyclic bending and charge-discharge processes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Coordinating Group report

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    In December 1992, western governors and four federal agencies established a Federal Advisory Committee to Develop On-site Innovative Technologies for Environmental Restoration and Waste Management (the DOIT Committee). The purpose of the Committee is to advise the federal government on ways to improve waste cleanup technology development and the cleanup of federal sites in the West. The Committee directed in January 1993 that information be collected from a wide range of potential stakeholders and that innovative technology candidate projects be identified, organized, set in motion, and evaluated to test new partnerships, regulatory approaches, and technologies which will lead to improve site cleanup. Five working groups were organized, one to develop broad project selection and evaluation criteria and four to focus on specific contaminant problems. A Coordinating Group comprised of working group spokesmen and federal and state representatives, was set up to plan and organize the routine functioning of these working groups. The working groups were charged with defining particular contaminant problems; identifying shortcomings in technology development, stakeholder involvement, regulatory review, and commercialization which impede the resolution of these problems; and identifying candidate sites or technologies which could serve as regional innovative demonstration projects to test new approaches to overcome the shortcomings. This report from the Coordinating Group to the DOIT Committee highlights the key findings and opportunities uncovered by these fact-finding working groups. It provides a basis from which recommendations from the DOIT Committee to the federal government can be made. It also includes observations from two public roundtables, one on commercialization and another on regulatory and institutional barriers impeding technology development and cleanup.

  18. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  19. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

    2012-05-01

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  20. Fluorescent discharge lamp

    Science.gov (United States)

    Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

    1982-01-01

    A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

  1. Fluorescent discharge lamp

    Science.gov (United States)

    Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

    1982-07-01

    A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

  2. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  3. Enterprise Coordination on the Internet

    OpenAIRE

    Charles Petrie

    2011-01-01

    Enterprises are now connected internally and externally to other Enterprises via the Internet in ways that are increasingly difficult to manage, especially as these interconnections become more dynamic. Current methods of coordinating the effects of change as they propagate through these networks of connections are not likely to scale. What is needed is a new paradigm for how the Internet supports such coordination. Indeed, the Internet should and could provide fundamental coordination functi...

  4. Toroidal equilibria in spherical coordinates

    OpenAIRE

    Tsui, K. H.

    2009-01-01

    The standard Grad-Shafranov equation for axisymmetric toroidal plasma equilibrium is customary expressed in cylindrical coordinates with toroidal contours, and through which benchmark equilibria are solved. An alternative approach to cast the Grad-Shafranov equation in spherical coordinates is presented. This equation, in spherical coordinates, is examined for toroidal solutions to describe low $\\beta$ Solovev and high $\\beta$ plasma equilibria in terms of elementary functions.

  5. Fluorescent radiation converter

    Science.gov (United States)

    Viehmann, W. (Inventor)

    1981-01-01

    A fluorescence radiation converter is described which includes a substantially undoped optically transparent substrate and a waveshifter coating deposited on at least one portion of the substrate for absorption of radiation and conversion of fluorescent radiation. The coating is formed to substantially 1000 g/liter of a solvent, 70 to 200 g/liter of an organic polymer, and 0.2 to 25 g/liter of at least one organic fluorescent dye. The incoming incident radiation impinges on the coating. Radiation is absorbed by the fluorescent dye and is re-emitted as a longer wavelength radiation. Radiation is trapped within the substrate and is totally internally reflected by the boundary surface. Emitted radiation leaves the substrate ends to be detected.

  6. Fluorescent filtered electrophosphorescence

    Science.gov (United States)

    Forrest, Stephen R [Princeton, NJ; Sun, Yiru [Princeton, NJ; Giebink, Noel [Princeton, NJ; Thompson, Mark E [Anaheim Hills, CA

    2009-01-06

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  7. Introduction to fluorescence

    CERN Document Server

    Jameson, David M

    2014-01-01

    "An essential contribution to educating scientists in the principles of fluorescence. It will also be an important addition to the libraries of practitioners applying the principles of molecular fluorescence."-Ken Jacobson, Kenan Distinguished Professor of Cell Biology and Physiology, University of North Carolina at Chapel Hill"An exquisite compendium of fluorescence and its applications in biochemistry enriched by a very exciting historical perspective. This book will become a standard text for graduate students and other scientists."-Drs. Zygmunt (Karol) Gryczynski and Ignacy Gryczynski, University of North Texas Health Science Center"… truly a masterwork, combining clarity, precision, and good humor. The reader, novice or expert, will be pleased with the text and will not stop reading. It is a formidable account of the fluorescence field, which has impacted the life sciences so considerably in the last 60 years."-Jerson L. Silva, M.D., Ph.D., Professor and Director, National Institute of Science and Tech...

  8. Consideration in GIS insulation coordination

    Energy Technology Data Exchange (ETDEWEB)

    Bargigia, A.

    1990-01-01

    Analysis of electrical system failures reveals that many are caused by insulation breakdowns due to overvoltages. The problem of insulation co-ordination is then one of the most important aspects in the design of an electrical system. Insulation co-ordination of gas-insulated sub-stations (GIS) has recently received much attention especially due to a large diffusion of this insulation technique. In this review of GIS insulation co-ordination, attention is given to the impact on the insulation co-ordination strategy of the metal-clad disconnector performance during capacity current switching operations.

  9. Aminoquinoline based highly sensitive fluorescent sensor for lead(II) and aluminum(III) and its application in live cell imaging

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Thangaraj; Sivaraman, Gandhi [School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India); Mahesh, Ayyavu, E-mail: mahesh.a06@gmail.com [School of Biological Sciences, Madurai Kamaraj University, Madurai 625021 (India); Chellappa, Duraisamy, E-mail: dcmku123@gmail.com [School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India)

    2015-01-01

    Highlights: • Aminoquinoline derivative was synthesized and used to recognize Pb{sup 2+}/Al{sup 3+}. • ANQ was high sensitive, selective and turn-on sensor for Pb{sup 2+}/Al{sup 3+}. • The Pb{sup 2+} detection limit (2.08 × 10{sup −9} mol L{sup −1}) is reported. • This fluorescence change was further supported by DFT/TD-DFT calculations. • The probe is applied successfully for recognizing intracellular Pb{sup 2+}/Al{sup 3+} within living cells. - Abstract: We have synthesized a new probe 5-((anthracen-9-ylmethylene) amino)quinolin-10-ol (ANQ) based on anthracene platform. The probe was tested for its sensing behavior toward heavy metal ions Hg{sup 2+}, Pb{sup 2+}, light metal Al{sup 3+} ion, alkali, alkaline earth, and transition metal ions by UV–visible and fluorescent techniques in ACN/H{sub 2}O mixture buffered with HEPES (pH 7.4). It shows high selectivity toward sensing Pb{sup 2+}/Al{sup 3+} metal ions. Importantly, 10-fold and 5- fold fluorescence enhancement at 429 nm was observed for probe upon complexation with Pb{sup 2+} and Al{sup 3+} ions, respectively. This fluorescence enhancement is attributable to the prevention of photoinduced electron transfer. The photonic studies indicate that the probe can be adopted as a sensitive fluorescent chemosensor for Pb{sup 2+} and Al{sup 3+} ions.

  10. Fluorescence (Multiwave) Confocal Microscopy.

    Science.gov (United States)

    Welzel, J; Kästle, Raphaela; Sattler, Elke C

    2016-10-01

    In addition to reflectance confocal microscopy, multiwave confocal microscopes with different laser wavelengths in combination with exogenous fluorophores allow fluorescence mode confocal microscopy in vivo and ex vivo. Fluorescence mode confocal microscopy improves the contrast between the epithelium and the surrounding soft tissue and allows the depiction of certain structures, like epithelial tumors, nerves, and glands. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Hybrid fluorescence tomography/x-ray tomography improves reconstruction quality

    Science.gov (United States)

    Schulz, R. B.; Ale, A.; Sarantopoulos, A.; Freyer, M.; Söhngen, R.; Zientkowska, M.; Ntziachristos, V.

    2009-07-01

    A novel hybrid imaging system for simultaneous X-ray and Fluorescence Tomography is presented, capitalizing on 360°-projection free-space fluorescence tomography. The system is implemented within a commercial micro-CT scanner allowing reconstructions with a resolution of 95μm. Acquired data sets are intrinsically coregistered in the same coordinate system and can be used to correctly localize reconstructed fluorescence distributions with morphological features. More importantly, the micro-CT data, automatically segmented into different organ and tissue segments can be used to guide the fluorescence reconstruction algorithm and reduce the ill coditioning of the inverse problem. We showcase the use of the system and the improvements in image quality for lesions in brain and lung.

  12. coordination polymer with a coordinated nitro group of 2-nitrobenzoate

    Indian Academy of Sciences (India)

    WINTEC

    For correspondence. A one-dimensional barium(II) coordination polymer with a coordinated nitro group of 2-nitrobenzoate*. BIKSHANDARKOIL R SRINIVASAN. 1,#. , SANTOSH Y SHETGAONKAR. 1 and. PALLEPOGU RAGHAVAIAH. 1,2. 1. Department of Chemistry, Goa University, Goa 403 206. 2. School of Chemistry ...

  13. An insight into the communication between β-olefin/phenyl olefin-mediated acceptors and porphyrin π-system: a way to establish porphyrin based chemodosimeters and chemosensors.

    Science.gov (United States)

    Chahal, Mandeep K; Sankar, Muniappan; Butcher, Ray J

    2017-02-08

    The synthesis of three new classes of mixed β-pyrrole substituted tetraphenylporphyrins, MTPP(R), MTPP(Br) 2 (R) (where R = -CH[double bond, length as m-dash]C(CN) 2 , -CH[double bond, length as m-dash]C(CN)(COOC 2 H 5 ), -CH[double bond, length as m-dash](CN)(COOH) and M = 2H, Ni(ii), Cu(ii)) and MTPP(NO 2 )(Ph-p-R') 2 (R' = -CHO and -CH[double bond, length as m-dash]C(CN) 2 and M = 2H, Ni(ii), Cu(ii)) have been reported. The crystal structures of CuTPP(Br) 2 -ECA (7a), NiTPP(NO 2 )(Ph-p-CHO) 2 (9) and NiTPP(NO 2 )(Ph-p-CH[double bond, length as m-dash](CN) 2 ) 2 (10) are highly nonplanar among β-trisubstituted porphyrins reported to date as evidenced from the mean displacement of β-pyrrole carbon (ΔC β ) in the range ±(0.39-0.674) Å. The olefin mediated ethyl cyanoacetate is in plane with the porphyrin core in CuTPP(Br) 2 -ECA (the dihedral angle relative to the pyrrole NC 4 -mean plane is 39.81°) while dicyanovinyl stays aside for NiTPP(NO 2 )(Ph-p-CH[double bond, length as m-dash](CN) 2 ) 2 (dihedral angles relative to the pyrrole NC 4 -mean plane are 75.03° and 67.47°). NiTPP-MN (2), NiTPP-ECA (3), NiTPP(Br) 2 -MN (6) and NiTPP(Br) 2 -ECA (7) act as chemodosimeters for toxic CN - ions whereas NiTPP-CAA (4) and NiTPP(Br) 2 -CAA (8) act as chemosensors to detect toxic ions such as CN - , F - and OAc - depending on the acceptor strength and an obstacle in the conjugation pathway. The dicyanovinyl group in the phenyl olefinic-mediated porphyrin NiTPP(NO 2 )(Ph-p-CH[double bond, length as m-dash](CN) 2 ) 2 (10) also acts as chemodosimeter for CN - ions but no vivid changes are observed via different spectroscopic methods.

  14. Fluorescence-based biosensors.

    Science.gov (United States)

    Strianese, Maria; Staiano, Maria; Ruggiero, Giuseppe; Labella, Tullio; Pellecchia, Claudio; D'Auria, Sabato

    2012-01-01

    The field of optical sensors has been a growing research area over the last three decades. A wide range of books and review articles has been published by experts in the field who have highlighted the advantages of optical sensing over other transduction methods. Fluorescence is by far the method most often applied and comes in a variety of schemes. Nowadays, one of the most common approaches in the field of optical biosensors is to combine the high sensitivity of fluorescence detection in combination with the high selectivity provided by ligand-binding proteins. In this chapter we deal with reviewing our recent results on the implementation of fluorescence-based sensors for monitoring environmentally hazardous gas molecules (e.g. nitric oxide, hydrogen sulfide). Reflectivity-based sensors, fluorescence correlation spectroscopy-based (FCS) systems, and sensors relying on the enhanced fluorescence emission on silver island films (SIFs) coupled to the total internal reflection fluorescence mode (TIRF) for the detection of gliadin and other prolamines considered toxic for celiac patients are also discussed herein.

  15. On Coordinating Collaborative Objects

    Directory of Open Access Journals (Sweden)

    Abdessamad Imine

    2010-07-01

    Full Text Available A collaborative object represents a data type (such as a text document designed to be shared by a group of dispersed users. The Operational Transformation (OT is a coordination approach used for supporting optimistic replication for these objects. It allows the users to concurrently update the shared data and exchange their updates in any order since the convergence of all replicas, i.e. the fact that all users view the same data, is ensured in all cases. However, designing algorithms for achieving convergence with the OT approach is a critical and challenging issue. In this paper, we propose a formal compositional method for specifying complex collaborative objects. The most important feature of our method is that designing an OT algorithm for the composed collaborative object can be done by reusing the OT algorithms of component collaborative objects. By using our method, we can start from correct small collaborative objects which are relatively easy to handle and incrementally combine them to build more complex collaborative objects.

  16. Alkynyl-naphthalimide Fluorophores: Gold Coordination Chemistry and Cellular Imaging Applications.

    Science.gov (United States)

    Langdon-Jones, Emily E; Lloyd, David; Hayes, Anthony J; Wainwright, Shane D; Mottram, Huw J; Coles, Simon J; Horton, Peter N; Pope, Simon J A

    2015-07-06

    A range of fluorescent alkynyl-naphthalimide fluorophores has been synthesized and their photophysical properties examined. The fluorescent ligands are based upon a 4-substituted 1,8-naphthalimide core and incorporate structural variations (at the 4-position) to tune the amphiphilic character: chloro (L1), 4-[2-(2-aminoethoxy)ethanol] (L2), 4-[2-(2-methoxyethoxy)ethylamino] (L3), piperidine (L4), morpholine (L5), 4-methylpiperidine (L6), and 4-piperidone ethylene ketal (L7) variants. The amino-substituted species (L2-L7) are fluorescent in the visible region at around 517-535 nm through a naphthalimide-localized intramolecular charge transfer (ICT), with appreciable Stokes' shifts of ca. 6500 cm(-1) and lifetimes up to 10.4 ns. Corresponding two-coordinate Au(I) complexes [Au(L)(PPh3)] were isolated, with X-ray structural studies revealing the expected coordination mode via the alkyne donor. The Au(I) complexes retain the visible fluorescence associated with the coordinated alkynyl-naphthalimide ligand. The ligands and complexes were investigated for their cytotoxicity across a range of cell lines (LOVO, MCF-7, A549, PC3, HEK) and their potential as cell imaging agents for HEK (human embryonic kidney) cells and Spironucleus vortens using confocal fluorescence microscopy. The images reveal that these fluorophores are highly compatible with fluorescence microscopy and show some clear intracellular localization patterns that are dependent upon the specific nature of the naphthalimide substituent.

  17. Selective fluorescence sensing of Cu(II) and Zn(II) using a simple Schiff base ligand: Naked eye detection and elucidation of photoinduced electron transfer (PET) mechanism

    Science.gov (United States)

    Ganguly, Aniruddha; Ghosh, Soumen; Kar, Samiran; Guchhait, Nikhil

    2015-05-01

    A simple Schiff base compound 2-((cyclohexylmethylimino)-methyl)-naphthalen-1-ol (2CMIMN1O) has been synthesized and characterized by 1H NMR, 13C NMR and FT-IR spectroscopic techniques. A significantly low emission yield of the compound has been rationalized in anticipation with photo-induced electron transfer (PET) from the imine receptor moiety to the naphthalene fluorophore unit. Consequently, an evaluation of the transition metal ion-induced modification of the fluorophore-receptor communication reveals the promising prospect of the title compound to function as a chemosensor for Cu2+ and Zn2+ ions selectively, through remarkable fluorescence enhancement as well as visual changes. While perturbation of the PET process has been argued to be the plausible mechanism behind the fluorescence enhancement, the selectivity for these two metal ions has been interpreted on the grounds of an appreciably strong binding interaction. Particularly notable aspects regarding the chemosensory activity of the compound is its ability to detect the aforesaid transition metal ions down to the level of micromolar concentration (detection limit being 2.74 and 2.27 ppm respectively), along with a simple and efficient synthetic procedure.

  18. Fluorescence and co-fluorescence of Tb(3+) and Eu(3+) in acetonitrile using 2,6-pyridine dicarboxylic acid as ligand.

    Science.gov (United States)

    Maji, S; Kumar, Satendra; Sankaran, K

    2015-01-25

    Fluorescence from Tb(3+) and Eu(3+) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent. The enhancement in fluorescence intensity because of non-aqueous environment provided by the MeCN is less significant, where as fluorescence enhancement of more than two orders of magnitude has been observed with the addition of La(3+); a process known as co-fluorescence in MeCN. The present study demonstrates for the first time co-fluorescence of Tb(3+) and Eu(3+) with excitation through the absorption of PDA. Intermolecular energy transfer is believed to be responsible for co-fluorescence enhancement and it becomes possible as the quenching due to water at the secondary coordination spheres of Tb(3+) and Eu(3+) is reduced when MeCN is used as solvent. Copyright © 2014. Published by Elsevier B.V.

  19. Circular dichroism spectroscopy of fluorescent proteins

    NARCIS (Netherlands)

    Visser, N.V.; Hink, M.A.; Borst, J.W.; Krogt, van der G.N.M.; Visser, A.J.W.G.

    2002-01-01

    Circular dichroism (CD) spectra have been obtained from several variants of green fluorescent protein: blue fluorescent protein (BFP), enhanced cyan fluorescent protein (CFP), enhanced green fluorescent protein (GFP), enhanced yellow fluorescent protein (YFP), all from Aequorea victoria, and the red

  20. Coordination of Conditional Poisson Samples

    Directory of Open Access Journals (Sweden)

    Grafström Anton

    2015-12-01

    Full Text Available Sample coordination seeks to maximize or to minimize the overlap of two or more samples. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly used for estimation purposes and to reduce data collection costs. Negative coordination is mainly performed to diminish the response burden of the sampled units. Poisson sampling design with permanent random numbers provides an optimum coordination degree of two or more samples. The size of a Poisson sample is, however, random. Conditional Poisson (CP sampling is a modification of the classical Poisson sampling that produces a fixed-size πps sample. We introduce two methods to coordinate Conditional Poisson samples over time or simultaneously. The first one uses permanent random numbers and the list-sequential implementation of CP sampling. The second method uses a CP sample in the first selection and provides an approximate one in the second selection because the prescribed inclusion probabilities are not respected exactly. The methods are evaluated using the size of the expected sample overlap, and are compared with their competitors using Monte Carlo simulation. The new methods provide a good coordination degree of two samples, close to the performance of Poisson sampling with permanent random numbers.

  1. 75 FR 55947 - Coordinated Communications

    Science.gov (United States)

    2010-09-15

    ... for Final Rules on General Public Political Communications Coordinated with Candidates and Party... Coalition, the Commission defined a new term, ``coordinated general public political communication'' (``GPPC... communications directed or made by persons who previously served as an employee of a candidate or a political...

  2. Introduction to coordinated linear systems

    NARCIS (Netherlands)

    Kempker, P.L.

    2014-01-01

    This chapter serves as an introduction to the concepts of coordinated linear systems, in formal as well as intuitive terms. The concept of a coordinated linear system is introduced and formulated, and some basic properties are derived, providing both a motivaton and a formal basis for the following

  3. Bimanual coordination in dyslexic adults.

    Science.gov (United States)

    Moore, L H; Brown, W S; Markee, T E; Theberge, D C; Zvi, J C

    1995-06-01

    Various types of dyslexia have been associated with tactile-motor coordination deficits and inefficient transfer of information between the two cerebral hemispheres. Twenty-one dyslexic adults were compared to 21 controls on the Bimanual Coordination Task, a test of tactile-motor coordination and interhemispheric collaboration. When compared to control subjects, dyslexics showed a consistent pattern of deficits in bimanual motor coordination, both with and without visual feedback. In particular, dyslexics had greater difficulty relative to normals when the left hand had to move faster than the right, and when the hands had to make opposite (mirror-image) movements, suggesting problems with interhemispheric modulation of visuomotor control. In addition, accuracy on this bimanual coordination task was significantly correlated with the Block Design subtest of the WAIS--R, but not with a rhyme fluency task, suggesting some contribution of right hemisphere controlled visuospatial skill to performance.

  4. Unconventional Molecular Design Approach of High-Efficiency Deep Blue Thermally Activated Delayed Fluorescent Emitters Using Indolocarbazole as an Acceptor.

    Science.gov (United States)

    Seo, Jeong-A; Im, Yirang; Han, Si Hyun; Lee, Chil Won; Lee, Jun Yeob

    2017-11-01

    Unconventional blue thermally activated delayed fluorescent emitters having electron-donating type indolocarbazole as an acceptor were developed by attaching carbazolylcarbazole or acridine donors to the indolocarbazole acceptor. Three compounds were derived from the indolocarbazole acceptor. The indolocarbazole-acridine combined products showed efficient delayed fluorescent behavior and a high quantum efficiency of 19.5% with a color coordinate of (0.15, 0.16) when they were evaluated as thermally activated delayed fluorescent emitters in deep blue fluorescent devices. This is the first demonstration of the use of electron-donating carbazole-derived moieties as efficient acceptor units of blue thermally activated delayed fluorescent emitters.

  5. Keep Meaning in Conversational Coordination

    Directory of Open Access Journals (Sweden)

    Elena Clare Cuffari

    2014-12-01

    Full Text Available Coordination is a widely employed term across recent quantitative and qualitative approaches to intersubjectivity, particularly approaches that give embodiment and enaction central explanatory roles. With a focus on linguistic and bodily coordination in conversational contexts, I review the operational meaning of coordination in recent empirical research and related theorizing of embodied intersubjectivity. This discussion articulates what must be involved in treating linguistic meaning as dynamic processes of coordination. The coordination approach presents languaging as a set of dynamic self-organizing processes and actions on multiple timescales and across multiple modalities that come about and work in certain domains (those jointly constructed in social, interactive, high-order sense-making. These processes go beyond meaning at the level that is available to first-person experience. I take one crucial consequence of this to be the ubiquitously moral nature of languaging with others. Languaging coordinates experience, among other levels of behavior and event. Ethical effort is called for by the automatic autonomy-influencing forces of languaging as coordination.

  6. Keep meaning in conversational coordination.

    Science.gov (United States)

    Cuffari, Elena C

    2014-01-01

    Coordination is a widely employed term across recent quantitative and qualitative approaches to intersubjectivity, particularly approaches that give embodiment and enaction central explanatory roles. With a focus on linguistic and bodily coordination in conversational contexts, I review the operational meaning of coordination in recent empirical research and related theorizing of embodied intersubjectivity. This discussion articulates what must be involved in treating linguistic meaning as dynamic processes of coordination. The coordination approach presents languaging as a set of dynamic self-organizing processes and actions on multiple timescales and across multiple modalities that come about and work in certain domains (those jointly constructed in social, interactive, high-order sense-making). These processes go beyond meaning at the level that is available to first-person experience. I take one crucial consequence of this to be the ubiquitously moral nature of languaging with others. Languaging coordinates experience, among other levels of behavior and event. Ethical effort is called for by the automatic autonomy-influencing forces of languaging as coordination.

  7. Coordinating distributed work : Exploring situated coordination with gaming-simulation

    NARCIS (Netherlands)

    van Laere, J.

    2003-01-01

    Organizational work has become more and more distributed nowadays. Information and communication technologies (ICT) provide opportunities to improve coordination of distributed work, but in practice many organizations struggle with integrating new organizational structures, new work practices and

  8. Concentrators using fluorescent substances

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, M.; Tsukamoto, M. (Hitachi Seisakusho K.K., Tokyo (Japan))

    1990-01-01

    In luminescent concentrators - plates of polymethylmethacrylate (PMMA) or other transparent material with a fluorescent compound dispersed within them - incident light is trapped and concentrated by internal reflection, and shifted to a longer wavelength, as it interacts with fluorescent particles. Experience with the use of luminescent concentrators for electricity generation in conjunction with solar cells, in solar heaters, in amplifiers for light intensity, in long-wave converters and in display panels is discussed. Solar energy conversion efficiencies of 4-5% have been obtained in generating systems combining concentrators containing Fluorol 555 or Rhodamin 6G with GaAs solar cells. (author).

  9. Smartphone fluorescence spectroscopy

    Science.gov (United States)

    Yu, Hojoeng; Tan, Yafang; Cunningham, Brian T.

    2014-03-01

    We demonstrate the first use of smartphone spectrophotometry for readout of fluorescence-based biological assays. We evaluated the smartphone fluorimeter in the context of a fluorescent molecular beacon (MB) assay for detection of a specific nucleic acid sequences in a liquid test sample. The capability of distinguishing a one-point mismatch is also demonstrated by detecting single-base mutation in target nucleic acids. Our approach offers a route towards portable biomolecular assays for viral/bacterial pathogens, disease biomarkers, and toxins.

  10. Smartphone fluorescence spectroscopy.

    Science.gov (United States)

    Yu, Hojeong; Tan, Yafang; Cunningham, Brian T

    2014-09-02

    We demonstrate the first use of smartphone spectrophotometry for readout of fluorescence-based biological assays. We evaluated the smartphone fluorimeter in the context of a fluorescent molecular beacon (MB) assay for detection of specific nucleic acid sequences in a liquid test sample and compared performance against a conventional laboratory fluorimeter. The capability of distinguishing a one-point mismatch is also demonstrated by detecting single-base mutation in target nucleic acids. Our approach offers a route toward portable biomolecular assays for viral/bacterial pathogens, disease biomarkers, and toxins.

  11. Coordinated action in multiteam systems.

    Science.gov (United States)

    Davison, Robert B; Hollenbeck, John R; Barnes, Christopher M; Sleesman, Dustin J; Ilgen, Daniel R

    2012-07-01

    This study investigated coordinated action in multiteam systems employing 233 correspondent systems, comprising 3 highly specialized 6-person teams, that were engaged in an exercise that was simultaneously "laboratory-like" and "field-like." It enriches multiteam system theory through the combination of theoretical perspectives from the team and the large organization literatures, underscores the differential impact of large size and modular organization by specialization, and demonstrates that conventional wisdom regarding effective coordination in traditional teams and large organizations does not always transfer to multiteam systems. We empirically show that coordination enacted across team boundaries at the component team level can be detrimental to performance and that coordinated actions enacted by component team boundary spanners and system leadership positively impact system performance only when these actions are centered around the component team most critical to addressing the demands of the task environment. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

  12. Coordination Games on Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Enea Pestelacci

    2010-07-01

    Full Text Available We propose a model in which agents of a population interacting according to a network of contacts play games of coordination with each other and can also dynamically break and redirect links to neighbors if they are unsatisfied. As a result, there is co-evolution of strategies in the population and of the graph that represents the network of contacts. We apply the model to the class of pure and general coordination games. For pure coordination games, the networks co-evolve towards the polarization of different strategies. In the case of general coordination games our results show that the possibility of refusing neighbors and choosing different partners increases the success rate of the Pareto-dominant equilibrium.

  13. Coordination theory and collaboration technology

    CERN Document Server

    Olson, Gary M; Smith, John B

    2001-01-01

    The National Science Foundation funded the first Coordination Theory and Collaboration Technology initiative to look at systems that support collaborations in business and elsewhere. This book explores the global revolution in human interconnectedness. It will discuss the various collaborative workgroups and their use in technology. The initiative focuses on processes of coordination and cooperation among autonomous units in human systems, in computer and communication systems, and in hybrid organizations of both systems. This initiative is motivated by three scientific issues which have been

  14. Fluorescence lifetime based bioassays

    Science.gov (United States)

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  15. Muscle coordination: the discussion continues

    Science.gov (United States)

    Prilutsky

    2000-01-01

    In this response, the major criticisms of the target article are addressed. Terminology from the target article that may have caused some confusion is clarified. In particular, the tasks that have the basic features of muscle coordination, as identified in the target article, have been limited in scope. A new metabolic optimization criterion suggested by Alexander (2000) is examined for its ability to predict muscle coordination in walking. Issues concerning the validation of muscle force predictions, the rules of muscle coordination, and the role of directional constraints in coordination of two-joint muscles are discussed. It is shown in particular that even in one-joint systems, the forces predicted by the criterion of Crowninshield and Brand (1981) depend upon the muscle moment arms and the physiological cross-sectional areas in much more complex ways than either previously assumed in the target article, or incorrectly derived by Herzog and Ait-Haddou (2000). It is concluded that the criterion of Crowninshield and Brand qualitatively predicts the basic coordination features of the major one- and two-joint muscles in a number of highly skilled, repetitive motor tasks performed by humans under predictable conditions and little demands on stability and accuracy. A possible functional significance of such muscle coordination may be the minimization of perceived effort, muscle fatigue, and/or energy expenditure.

  16. Fluorescent polymers from non-fluorescent photoreactive monomers.

    Science.gov (United States)

    Mueller, Jan O; Voll, Dominik; Schmidt, Friedrich G; Delaittre, Guillaume; Barner-Kowollik, Christopher

    2014-12-25

    A facile, fast and ambient-temperature avenue towards highly fluorescent polymers is introduced via polymerizing non-fluorescent photoreactive monomers based on light-induced NITEC chemistry, providing a platform technology for fluorescent polymers. The resulting polypyrazolines were analyzed in depth and the photo-triggered step-growth process was monitored in a detailed kinetic study.

  17. Fluorescence Microscopy of Single Molecules

    Science.gov (United States)

    Zimmermann, Jan; van Dorp, Arthur; Renn, Alois

    2004-01-01

    The investigation of photochemistry and photophysics of individual quantum systems is described with the help of a wide-field fluorescence microscopy approach. The fluorescence single molecules are observed in real time.

  18. Fluorescence spectroscopy in polymer science

    NARCIS (Netherlands)

    Raja, T.N.; Brouwer, A.M.; Demchenko, A.P.

    2011-01-01

    Polymer science is an interdisciplinary field, combining chemistry, physics, and in some cases biology. Structure, morphology, and dynamical phenomena in natural and synthetic polymers can be addressed using fluorescence spectroscopy. The most attractive aspect of fluorescent reporters is that their

  19. Who's who in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2008-01-01

    The Journal of Fluorescence's sixth Who's Who directory publishes the names, contact details, specialty keywords, and a brief description of scientists employing fluorescence methodology and instrumentation in their working lives. This is a unique reference.

  20. Sputum direct fluorescent antibody (DFA)

    Science.gov (United States)

    ... ency/article/003553.htm Sputum direct fluorescent antibody (DFA) test To use the sharing features on this page, please enable JavaScript. Sputum direct fluorescent antibody (DFA) is a lab test that looks for micro- ...

  1. Metallogels from Coordination Complexes, Organometallic, and Coordination Polymers.

    Science.gov (United States)

    Dastidar, Parthasarathi; Ganguly, Sumi; Sarkar, Koushik

    2016-09-20

    A supramolecular gel results from the immobilization of solvent molecules on a 3D network of gelator molecules stabilized by various supramolecular interactions that include hydrogen bonding, π-π stacking, van der Waals interactions, and halogen bonding. In a metallogel, a metal is a part of the gel network as a coordinated metal ion (in a discrete coordination complex), as a cross-linking metal node with a multitopic ligand (in coordination polymer), and as metal nanoparticles adhered to the gel network. Although the field is relatively new, research into metallogels has experienced a considerable upsurge owing to its fundamental importance in supramolecular chemistry and various potential applications. This focus review aims to provide an insight into the development of designing metallogelators. Because of the limited scope, discussions are confined to examples pertaining to metallogelators derived from discrete coordination complexes, organometallic gelators, and coordination polymers. This review is expected to enlighten readers on the current development of designing metallogelators of the abovementioned class of molecules. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A fluorescence scanning electron microscope

    OpenAIRE

    Kanemaru, Takaaki; Hirata, Kazuho; Takasu, Shin-ichi; Isobe, Shin-Ichiro; Mizuki, Keiji; Mataka, Shuntaro; Nakamura, Kei-ichiro

    2010-01-01

    Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM) and an electron microscope (EM). In the current study, a scanning electron microscope (SEM) (JEOL JXA8600 M) was combined with a fluorescence digital c...

  3. Who's who in fluorescence 2005

    CERN Document Server

    Geddes, Chris D

    2006-01-01

    The Journal of Fluorescence's third Who's Who directory publishes the names, contact details, specialty keywords, photographs, and a brief description of scientists employing fluorescence methodology and instrumentation in their working livesThe directory provides company contact details with a brief list of fluorescence-related products.

  4. Water-soluble conjugated polymers for fluorescent-enzyme assays.

    Science.gov (United States)

    Feng, Fude; Liu, Libing; Yang, Qiong; Wang, Shu

    2010-08-17

    Enzyme assays are receiving more and more research and application interest because of the rapidly increasing demands of clinical diagnosis, environmental analysis, drug discovery, and molecular biology. Water-soluble light-harvesting conjugated polymers (CPs) coordinate the action of a large number of absorbing units to afford an amplified fluorescence signal, which makes them useful as optical platforms in highly sensitive chemical and biological sensors. This Feature Article highlights recent developments of water-soluble CPs for fluorescent assays of enzymes. Different signal transduction mechanisms, such as electron transfer, fluorescence resonance energy transfer (FRET), and aggregation or conformation changes of CPs, are employed in these assays according to the dissimilar nature of enzymes. Potential challenges and future research directions in these approaches based on CPs are also discussed. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Werner coordination chemistry and neurodegeneration.

    Science.gov (United States)

    Telpoukhovskaia, Maria A; Orvig, Chris

    2013-02-21

    Neurodegenerative diseases are capturing the world's attention as being the next set of diseases we must tackle collectively. Not only are the patients experiencing gradual cognitive and physical decline in most cases, but these diseases are fatal with no prevention currently available. As these diseases are progressive, providing care and symptom treatment for the ageing population is becoming both a medical and a financial challenge. This review discusses how Werner coordination chemistry plays a role in three diseases - those of Alzheimer's, Parkinson's, and prions. Metal ions are considered to be involved in these diseases in part via their propensity to cause toxic aggregation of proteins. First, the coordination of metal ions, with emphasis on copper(II), to metalloproteins that are hallmarks of these diseases - amyloid β, α-synuclein, and prion, respectively - will be discussed. We will present the current understanding of the metal coordination environments created by the amino acids of these proteins, as well as metal binding affinity. Second, a diverse set of examples of rationally designed metal chelators to outcompete this deleterious binding will be examined based on coordination mode and affinity toward bio-relevant metal ions. Overall, this review will give a general overview of protein and metal chelator coordination environments in neurodegenerative diseases.

  6. Light Sheet Fluorescence Microscopy

    Science.gov (United States)

    Santi, Peter A.

    2011-01-01

    Light sheet fluorescence microscopy (LSFM) functions as a non-destructive microtome and microscope that uses a plane of light to optically section and view tissues with subcellular resolution. This method is well suited for imaging deep within transparent tissues or within whole organisms, and because tissues are exposed to only a thin plane of light, specimen photobleaching and phototoxicity are minimized compared to wide-field fluorescence, confocal, or multiphoton microscopy. LSFMs produce well-registered serial sections that are suitable for three-dimensional reconstruction of tissue structures. Because of a lack of a commercial LSFM microscope, numerous versions of light sheet microscopes have been constructed by different investigators. This review describes development of the technology, reviews existing devices, provides details of one LSFM device, and shows examples of images and three-dimensional reconstructions of tissues that were produced by LSFM. PMID:21339178

  7. Magnetic fluorescent lamp

    Science.gov (United States)

    Berman, S. M.; Richardson, R. W.

    1983-12-01

    The radiant emission of a mercury argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a zeeman splitting of approximately 1.7 times the thermal line width.

  8. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  9. Magnetic fluorescent lamp

    Science.gov (United States)

    Berman, S.M.; Richardson R.W.

    1983-12-29

    The radiant emission of a mercury-argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide Zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a Zeeman splitting of approximately 1.7 times the thermal line width.

  10. Fluorescent quantification of melanin

    OpenAIRE

    Fernandes, Bruno Pacheco; Matamá, Maria Teresa; Guimarães, Diana Isabel Pereira; Gomes, Andreia; Cavaco-Paulo, Artur

    2016-01-01

    Melanin quantification is reportedly performed by absorption spectroscopy, commonly at 405 nm. Here, we propose the implementation of fluorescence spectroscopy for melanin assessment. In a typical in vitro assay to assess melanin production in response to an external stimulus, absorption spectroscopy clearly overvalues melanin content. This method is also incapable of distinguishing non-melanotic/amelanotic control cells from those that are actually capable of performing melanogenesis. Theref...

  11. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    recycling , and can be disposed safely in a landfill. (2) LEDs offer reduced maintenance costs and fewer bulb replacements, significantly reducing...housings, plastic grates, old wiring) and the new LED technology (cardboard packaging) were broken down and separated into the appropriate container for... recycling . Several fixtures, ballasts and energy efficient fluorescent bulbs that were determined to be in pristine condition were returned to ATC

  12. A selective Chemosensor for Cysteine

    Indian Academy of Sciences (India)

    of important cellular functions including detoxification and metabolism.1 Variation in the physiological level of thiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) is linked to a number of diseases associated with leucocyteloss, psoriasis, liver damage, slow growth, hair depigmentation, edema, lethargy, ...

  13. Coordination Processes in International Organisations

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2008-01-01

    The EU is not a member of the International Labour Organisation (ILO), but relatively elaborate EU coordination takes place anyway. This paper addresses two research questions: 1) How is it possible to evaluate the coordination of the EU in its specific observable configuration in the ILO?, and 2......-à-vis their principals, the Member States. The Commission is the leading agent in the phase leading up to the Conference; the Presidency then takes over. On the one hand, due to the Treaty obligations and their interpretations by the Court of Justice, both the Presidency and the Commission are kept within tight limits...

  14. Blue fluorescent cGMP sensor for multiparameter fluorescence imaging.

    Directory of Open Access Journals (Sweden)

    Yusuke Niino

    Full Text Available Cyclic GMP (cGMP regulates many physiological processes by cooperating with the other signaling molecules such as cyclic AMP (cAMP and Ca(2+. Genetically encoded sensors for cGMP have been developed based on fluorescence resonance energy transfer (FRET between fluorescent proteins. However, to analyze the dynamic relationship among these second messengers, combined use of existing sensors in a single cell is inadequate because of the significant spectral overlaps. A single wavelength indicator is an effective alternative to avoid this problem, but color variants of a single fluorescent protein-based biosensor are limited. In this study, to construct a new color fluorescent sensor, we converted the FRET-based sensor into a single wavelength indicator using a dark FRET acceptor. We developed a blue fluorescent cGMP biosensor, which is spectrally compatible with a FRET-based cAMP sensor using cyan and yellow fluorescent proteins (CFP/YFP. We cotransfected them and loaded a red fluorescent probe for Ca(2+ into cells, and accomplished triple-parameter fluorescence imaging of these cyclic nucleotides and Ca(2+, confirming the applicability of this combination to individually monitor their dynamics in a single cell. This blue fluorescent sensor and the approach using this FRET pair would be useful for multiparameter fluorescence imaging to understand complex signal transduction networks.

  15. Coordination games on directed graphs

    NARCIS (Netherlands)

    K.R. Apt (Krzysztof); S.E. Simon (Sunil); D.K. Wojtczak (Dominik)

    2016-01-01

    textabstractWe study natural strategic games on directed graphs, which capture the idea of coordination in the absence of globally common strategies. We show that these games do not need to have a pure Nash equilibrium and that the problem of determining their existence is NP-complete. The same

  16. [Coordination in oncology, pivot nurses].

    Science.gov (United States)

    Feld, Dominique

    2016-06-01

    The function of the pivot nurse was created when the Cancer Plans were first introduced to improve patient management and has constantly developed since then. It is an essential role for the coordination of care and the different players involved along the patient's care pathway. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Strichartz Estimates in Spherical Coordinates

    OpenAIRE

    Cho, Yonggeun; Lee, Sanghyuk

    2012-01-01

    In this paper we study Strichartz estimates for dispersive equations which are defined by radially symmetric pseudo-differential operators, and of which initial data belongs to spaces of Sobolev type defined in spherical coordinates. We obtain the space time estimates on the best possible range including the endpoint cases.

  18. Atomic coordination reflects peptide immunogenicity

    Directory of Open Access Journals (Sweden)

    Georgios S.E. Antipas

    2016-01-01

    Full Text Available We demonstrated that the immunological identity of variant peptides may be accurately predicted on the basis of atomic coordination of both unprotonated and protonated tertiary structures, provided that the structure of the native peptide (index is known. The metric which was discovered to account for this discrimination is the coordination difference between the variant and the index; we also showed that increasing coordination difference in respect to the index was correlated to a correspondingly weakening immunological outcome of the variant. Additionally, we established that this metric quickly seizes to operate beyond the peptide scale, e.g. over a coordination shell inclusive of atoms up to a distance of 7 Å away from the peptide or over the entire pMHC-TCR complex. Analysis of molecular orbital interactions over a range of formal charges further revealed that the N-terminus of the agonists was always able to sustain a stable ammonium (NH3+ group which was consistently absent in antagonists. We deem that the presence of NH3+ constitutes a secondary observable with a biological consequence, signifying a change in T cell activation. While our analysis of protonated structures relied on the quantum chemical relaxation of the H species, the results were consistent over a wide range of peptide charge and spin polarization conditions.

  19. Spin-crossover coordination nanoparticles.

    Science.gov (United States)

    Volatron, Florence; Catala, Laure; Rivière, Eric; Gloter, Alexandre; Stéphan, Odile; Mallah, Talal

    2008-08-04

    Spin-crossover coordination nanoparticles of the cyanide-bridged three-dimensional network Fe(pyrazine){Pt(CN) 4} were prepared at three different sizes using a microemulsion. The 14 nm particles present a transition centered around 265 K with a hysteresis of 6 K.

  20. Mutually coordinated anticipatory multimodal interaction

    NARCIS (Netherlands)

    Nijholt, Antinus; Reidsma, Dennis; van Welbergen, H.; op den Akker, Hendrikus J.A.; Ruttkay, Z.M.; Esposito, A.; Bourbakis, N.G.; Avouris, N.; Hatzilygeroudis, I.

    2008-01-01

    We introduce our research on anticipatory and coordinated interaction between a virtual human and a human partner. Rather than adhering to the turn taking paradigm, we choose to investigate interaction where there is simultaneous expressive behavior by the human interlocutor and a humanoid. We have

  1. Archimedes' Principle in General Coordinates

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Archimedes' principle is well known to state that a body submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Herein, Archimedes' principle is derived from first principles by using conservation of the stress-energy-momentum tensor in general coordinates. The resulting expression for the force is…

  2. Coordinating talk and practical action

    DEFF Research Database (Denmark)

    Oshima, Sae; Streeck, Jürgen

    2015-01-01

    This paper investigates how talk and practical action are coordinated during one type of activity involving professional communication: the service-assessment sequence in hair salons. During this activity, a practical inspection of the haircut must be coupled with sequentially produced verbal acts...

  3. Fluorescent temperature sensor

    Science.gov (United States)

    Baker, Gary A [Los Alamos, NM; Baker, Sheila N [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

    2009-03-03

    The present invention is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

  4. Fluorescent Europium Chelate Stain

    Science.gov (United States)

    Scaff, W. L.; Dyer, D. L.; Mori, K.

    1969-01-01

    The europium chelate of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (thenoyl-trifluoroacetone; TTA) is firmly bound to microorganisms. It fluoresces brightly at 613 nm with activation at 340 nm. Cells may be stained with 10−3m chelate in 50% ethyl alcohol, followed by washing with 50% ethyl alcohol. Equal or better stains are produced with 10−3m aqueous europium salt, water wash, and 10−2m aqueous TTA. A noncomplexing buffer should be used to maintain the pH at 6.5 to 6.8. Images PMID:4181107

  5. Development of a fluorescent cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, B.C.; Buchwald, M.I.; Epstein, R.I.; Gosnell, T.R.; Mungan, C.E.

    1995-10-01

    Recent work at Los Alamos National Laboratory has demonstrated the physical principles for a new type of solid-state cryocooler based on anti-Stokes fluorescence. Design studies indicate that a vibration-free, low-mass ``fluorescent cryocooler`` could operate for years with efficiencies and cooling powers comparable to current commercial systems. This paper presents concepts for a fluorescent cryocooler, design considerations and expected performance.

  6. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    Science.gov (United States)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  7. A coordination theory for intelligent machines

    Science.gov (United States)

    Wang, Fei-Yue; Saridis, George N.

    1990-01-01

    A formal model for the coordination level of intelligent machines is established. The framework of the coordination level investigated consists of one dispatcher and a number of coordinators. The model called coordination structure has been used to describe analytically the information structure and information flow for the coordination activities in the coordination level. Specifically, the coordination structure offers a formalism to (1) describe the task translation of the dispatcher and coordinators; (2) represent the individual process within the dispatcher and coordinators; (3) specify the cooperation and connection among the dispatcher and coordinators; (4) perform the process analysis and evaluation; and (5) provide a control and communication mechanism for the real-time monitor or simulation of the coordination process. A simple procedure for the task scheduling in the coordination structure is presented. The task translation is achieved by a stochastic learning algorithm. The learning process is measured with entropy and its convergence is guaranteed. Finally, a case study of the coordination structure with three coordinators and one dispatcher for a simple intelligent manipulator system illustrates the proposed model and the simulation of the task processes performed on the model verifies the soundness of the theory.

  8. Highly Efficient Soluble Blue Delayed Fluorescent and Hyperfluorescent Organic Light-Emitting Diodes by Host Engineering.

    Science.gov (United States)

    Jeon, Sang Kyu; Park, Hee-Jun; Lee, Jun Yeob

    2018-01-30

    Solution-processed high-efficiency fluorescent organic light-emitting diodes with an external quantum efficiency over 18% were developed by engineering a host material and device structure designed for solution process. A high triplet energy host material designed for the solution process, (oxybis(3-(tert-butyl)-6,1-phenylene))bis(diphenylphosphine oxide) (DPOBBPE), worked efficiently as the host of blue fluorescent devices because of good solubility, high photoluminescence quantum yield, and good film properties. The DPOBBPE host enabled a high external quantum efficiency of 18.8% in the fluorescent organic light-emitting diodes by the solution process. Moreover, 25.8% external quantum efficiency in the soluble blue thermally activated delayed fluorescent devices was also realized. The 25.8% external quantum efficiency of the DPOBBPE delayed fluorescent device and 18.8% external quantum efficiency of the fluorescent device are the highest efficiency values achieved in the solution-processed blue fluorescent organic light-emitting diodes. Moreover, the solution-processed fluorescent device showed an improved blue color coordinate of (0.14, 0.20) compared to (0.17, 0.31) of the delayed fluorescent device.

  9. Diffraction phase and fluorescence microscopy.

    Science.gov (United States)

    Park, Yongkeun; Popescu, Gabriel; Badizadegan, Kamran; Dasari, Ramachandra R; Feld, Michael S

    2006-09-04

    We have developed diffraction phase and fluorescence (DPF) microscopy as a new technique for simultaneous quantitative phase imaging and epi-fluorescence investigation of live cells. The DPF instrument consists of an interference microscope, which is incorporated into a conventional inverted fluorescence microscope. The quantitative phase images are characterized by sub-nanometer optical path-length stability over periods from milliseconds to a cell lifetime. The potential of the technique for quantifying rapid nanoscale motions in live cells is demonstrated by experiments on red blood cells, while the composite phase-fluorescence imaging mode is exemplified with mitotic kidney cells.

  10. Fluorescent nanodiamonds for ultrasensitive detection

    Science.gov (United States)

    Kimball, Joseph; Shumilov, Dmytro; Maliwa, Badri; Zerda, T. W.; Rout, Bibhu; Fudala, Rafal; Raut, Sangram; Gryczynski, Ignacy; Simanek, Eric; Borejdo, Julian; Rich, Ryan; Akopova, Irina; Gryczynski, Zygmunt

    2014-03-01

    Fluorescent nanodiamonds (NDs) are new and emerging nanomaterials that have potential to be used as fluorescence imaging agents and also as a highly versatile platform for the controlled functionalization and delivery of a wide spectrum of therapeutic agents. We will utilize two experimental methods, TIRF, a relatively simple method based on total internal reflection fluorescence and SPRF, fluorescence enhanced by resonance coupling with surface plasmons. We estimate that the SPRF method will be 100 times sensitive than currently available similar detectors based on detectors. The ultimate goal of this research is to develop microarray platforms that could be used for sensitive, fast and inexpensive gene sequencing and protein detection.

  11. A novel dual-channel chemosensor for CN- using asymmetric double-azine derivatives in aqueous media and its application in bitter almond

    Science.gov (United States)

    Pei, Peng-Xiang; Hu, Jing-Han; Chen, Ying; Sun, You; Qi, Jing

    2017-06-01

    In this paper, we have designed and synthesized a novel sensor L1 based on asymmetric double-azine derivatives, which showed both ;naked eye; recognition and fluorescence responses for CN- in DMSO/H2O (v/v = 4:1, pH = 7.20) solution. This simple sensor L1 could distinguish CN- from coexisting anions via the way of deprotonation and sensing mechanism of intramolecular charge transfer (ICT), and the minimum detection limit on fluorescence response of the sensor L1 towards CN- was down to 9.47 × 10- 7 M. Moreover, we have successfully utilized the sensor L1 to detect CN- in bitter almond. Test strips containing L1 were also prepared, which could act as a practical colorimetric tool to detect CN- in aqueous media.

  12. Argumentation for coordinating shared activities

    Science.gov (United States)

    Clement, Bradley J.; Barrett, Anthony C.; Schaffer, Steven R.

    2004-01-01

    an increasing need for space missions to be able to collaboratively (and competitively) develop plans both within and across missions. In addition, interacting spacecraft that interleave onboard planning and execution must reach consensus on their commitments to each other prior to execution. In domains where missions have varying degrees of interaction and different constraints on communication and computation, the missions will require different coordination protocols in order to efficiently reach consensus with in their imposed deadlines. We describe a Shared Activity Coordination (SHAC) framework that provides a decentralized algorithm for negotiating the scheduling of shared activities over the lifetimes of multiple agents and a foundation for customizing protocols for negotiating planner interactions. We investigate variations of a few simple protocols based on argumentation and distributed constraints satisfaction techniques and evaluate their abilities to reach consistent solutions according to computation, time, and communication costs in an abstract domain where spacecraft propose joint measurements.

  13. A coordination language for databases

    DEFF Research Database (Denmark)

    Li, Ximeng; Wu, Xi; Lluch Lafuente, Alberto

    2017-01-01

    We present a coordination language for the modeling of distributed database applications. The language, baptized Klaim-DB, borrows the concepts of localities and nets of the coordination language Klaim but re-incarnates the tuple spaces of Klaim as databases. It provides high-level abstractions...... and primitives for the access and manipulation of structured data, with integrity and atomicity considerations. We present the formal semantics of Klaim-DB and develop a type system that avoids potential runtime errors such as certain evaluation errors and mismatches of data format in tables, which are monitored...... in the semantics. The use of the language is illustrated in a scenario where the sales from different branches of a chain of department stores are aggregated from their local databases. Raising the abstraction level and encapsulating integrity checks in the language primitives have benefited the modeling task...

  14. TURNAROUND COORDINATOR. YES OR NOT?

    Directory of Open Access Journals (Sweden)

    Martin HROMÁDKA

    2013-12-01

    Full Text Available Both low cost carriers ‘fresh wind’ and liberalisation of ground handling market makes airlines to be cost-wise in every single field. Thus, ground handling contract are cutting down in terms of their costs. Handling companies struggle with pressure being put from the market environment, they rush 25 minutes turnaround with couple of people. This can be potentially dangerous from the safety point of view. One of possible solutions seems to be introducing turnaround coordinator, person who would supervise the ramp handling procedures. This paper discusses the role of turnaround coordinator within the aircraft turnaround process. Duties and responsibilities of this person are described. However, not every airport is staffing this position. The survey shows that smaller airports pay much more attention to this issue than the big ones.

  15. Coordination Dynamics in Cognitive Neuroscience.

    Science.gov (United States)

    Bressler, Steven L; Kelso, J A Scott

    2016-01-01

    Many researchers and clinicians in cognitive neuroscience hold to a modular view of cognitive function in which the cerebral cortex operates by the activation of areas with circumscribed elementary cognitive functions. Yet an ongoing paradigm shift to a dynamic network perspective is underway. This new viewpoint treats cortical function as arising from the coordination dynamics within and between cortical regions. Cortical coordination dynamics arises due to the unidirectional influences imposed on a cortical area by inputs from other areas that project to it, combined with the projection reciprocity that characterizes cortical connectivity and gives rise to reentrant processing. As a result, cortical dynamics exhibits both segregative and integrative tendencies and gives rise to both cooperative and competitive relations within and between cortical areas that are hypothesized to underlie the emergence of cognition in brains.

  16. Coordination dynamics in cognitive neuroscience

    Directory of Open Access Journals (Sweden)

    Steven L Bressler

    2016-09-01

    Full Text Available Many researchers and clinicians in cognitive neuroscience hold to a modular view of cognitive function in which the cerebral cortex operates by the activation of areas with circumscribed elementary cognitive functions. Yet an ongoing paradigm shift to a dynamic network perspective is underway. This new viewpoint treats cortical function as arising from the coordination dynamics within and between cortical regions. Cortical coordination dynamics arises due to the unidirectional influences imposed on a cortical area by inputs from other areas that project to it, combined with the projection reciprocity that characterizes cortical connectivity and gives rise to reentrant processing. As a result, cortical dynamics exhibits both segregative and integrative tendencies and gives rise to both cooperative and competitive relations within and between cortical areas that are hypothesized to underlie the emergence of cognition in brains.

  17. Coordination strategies of crew management

    Science.gov (United States)

    Conley, Sharon; Cano, Yvonne; Bryant, Don

    1991-01-01

    An exploratory study that describes and contrasts two three-person flight crews performing in a B-727 simulator is presented. This study specifically attempts to delineate crew communication patterns accounting for measured differences in performance across routine and nonroutine flight patterns. The communication patterns in the two crews evaluated indicated different modes of coordination, i.e., standardization in the less effective crew and planning/mutual adjustment in the more effective crew.

  18. Medium voltage substation insulation coordination

    Energy Technology Data Exchange (ETDEWEB)

    Caccia, M.; Gambirasio, D. (SAE Sadelmi, Milan (Italy))

    1991-01-01

    With reference to the provisions contained in applicable CEI (Italian Electrotechnical Committee) and IEC (International Electrotechnical Commission) normatives, a review is made of design criteria for the coordination of medium voltage substation switchgear and control gear. The design problematics are discussed with reference to optimization of neutral grounding, three phase ac short circuit calculation methods, and methods for the evaluation of voltages in fault conditions.

  19. Self-organising coordination systems

    OpenAIRE

    Casadei, Matteo

    2009-01-01

    Many research fields are pushing the engineering of large-scale, mobile, and open systems towards the adoption of techniques inspired by self-organisation: pervasive computing, but also distributed artificial intelligence, multi-agent systems, social networks, peer-topeer and grid architectures exploit adaptive techniques to make global system properties emerge in spite of the unpredictability of interactions and behaviour. Such a trend is visible also in coordination models and languages, wh...

  20. Coordination Games on Directed Graphs

    Directory of Open Access Journals (Sweden)

    Krzysztof R. Apt

    2016-06-01

    Full Text Available We study natural strategic games on directed graphs, which capture the idea of coordination in the absence of globally common strategies. We show that these games do not need to have a pure Nash equilibrium and that the problem of determining their existence is NP-complete. The same holds for strong equilibria. We also exhibit some classes of games for which strong equilibria exist and prove that a strong equilibrium can then be found in linear time.

  1. International Tax Competition and Coordination

    OpenAIRE

    Michael Keen; Konrad, Kai A.

    2012-01-01

    This paper aims to provide a comprehensive survey of the theory of international tax competition. Starting with the standard framework, it visits the non-cooperative equilibrium of tax competition, analyses aspects of partial and regional coordination, repeated interaction, stock-flow-effects, agglomeration effects and time consistency issues in dynamic models. We discuss profit shifting in the Keen-Kanbur model and then survey frameworks to analyze countries’ bidding for firms, tax rate diff...

  2. Porphyrin coordination polymer nanospheres and nanorods

    Science.gov (United States)

    Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

    2013-09-10

    A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

  3. Porphyrin coordination polymer nanospheres and nanorods

    Science.gov (United States)

    Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

    2012-12-04

    A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

  4. A novel development of dithizone as a dual-analyte colorimetric chemosensor: detection and determination of cyanide and cobalt (II) ions in dimethyl sulfoxide/water media with biological applications.

    Science.gov (United States)

    Tavallali, Hossein; Deilamy-Rad, Gohar; Parhami, Abolfath; Mousavi, Seyede Zahra

    2013-08-05

    The behavior of dithizone (DTZ), an easily available dye has been studied for the first time in chromogenic sensing of CN(-) as an anionic species and for Co(2+) as a cationic species in DMSO/H2O media. So employing DTZ an efficient colorimetric chemosensor was afforded with a chromogenic selectivity for Co(2+) over other cations with detection limit of 0.04 μmol L(-1). The complex of Co(2+) with DTZ also displayed ability to detect up to 0.43 μmol L(-1) CN(-) (K(+) salts) among other competing anions through a fast response time of less than 30s which is much lower than most recently reported chromogenic probes. The linear dynamic ranges for the determination of Co(2+) and CN(-) were 0.3-4.4 and 3.3-58.6 μmol L(-1) respectively. This method could have potential application in a variety of cases requiring rapid and accurate analysis of Co(2+) and CN(-) for human serum and water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Coordinate unsaturation with fluorinated ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rack, J.L.; Hurlburt, P.K.; Anderson, O.P.; Strauss, S.H. [Colorado State Univ., Ft. Collins, CO (United States)

    1993-12-31

    The preparation and characterization of Zn(OTeF{sub 5}){sub 2} has resulted in a model compound with which to explore the concept of coordinative unsaturation. The coordination of solvents of varying donicity and dielectric constant to the Zn(II) ions in Zn(OTeF{sub 5}){sub 2} was studied by vapor phase monometry, NMR and IR spectroscopy, conductimetry, and X-Ray crystallography. The structures of [Zn(C{sub 6}H{sub 5}NO{sub 2}){sub 2}(OTeF{sub 5})2]2 and Zn(C{sub 6}H{sub 5}NO{sub 2}){sub 3}(OTEF{sub 5}){sub 2} demonstrate the electronic flexibility of some weakly coordinating solvents in that nitrobenzene can function as either an {eta}{sup 1}O or {eta}{sup 2}O,O`-ligand. The dependence of the number of bound solvent molecules and the degree of OTeF{sub 5}{minus} dissociation on solvent donor number and dielectric constant will be presented.

  6. Quantitative approach of speleothems fluorescence

    Science.gov (United States)

    Quiers, Marine; Perrette, Yves; Poulenard, Jérôme; Chalmin, Emilie; Revol, Morgane

    2014-05-01

    In this study, we propose a framework to interpret quantitatively the fluorescence of speleothems organic matter (OM) by the way of a bank of water-extracted organic matter. Due to its efficiency to described dissolved organic matter (DOM) characteritics, fluorescence has been used to determined DOM signatures in natural systems, water circulations, OM transfer from soils, OM evolution in soils or recently, DOM changes in engineered treatment systems. Fluorescence has also been used in speleothems studies, mainly as a growth indicator. Only few studies interpret it as an environmental proxy. Indeed, the fluorescence of OM provides information on the type of organic molecules trapped in speleothems and their evolutions. But the most direct information given by fluorescence is the variation of OM quantities. Actually, increase of fluorescence intensity is generally related to an increase in OM quantity but may also be induced by calcite optical effect or qualitative change of OM. However, analytical technics used in water environments cannot be used for speleothem samples. In this study we propose to give a frame to interpret quantitatively the fluorescence signal of speleothems. 3 different samples of stalagmites from french northern Prealps were used. To allow the quantification of the fluorescence signal, we need to measure the fluorescence and the quantity of organic matter on the same sample. OM of speleothems was extracted by an acid digestion method and analysed with a spectrofluorimeter. However, it was not possible to quantify directly the OM, as the extract solvant was a high-concentrated acid. To solve this problem, a calibration using soil extracts was realised. Soils were chosen in order to represent the diversity of OM present in the environment above the caves. Attention was focused on soil and vegetation types, and landuse. Organic material was water extracted from soils and its fluorescence was also measured. Total organic carbon was performed on the

  7. Shading correction and calibration in bacterial fluorescence measurement by image processing system

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    An image processing system with applications in bacterial (immuno-)fluorescence measurement has been developed. To reach quantitative results, correction for non-uniformities in system sensitivity, both as a function of time (calibration for drifts) and as a function of image coordinates (shading

  8. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  9. Visible fluorescent proteins for FRET

    NARCIS (Netherlands)

    Kremers, G.J.; Goedhart, J.; Gadella, T.W.J.

    2009-01-01

    This chapter discusses the use of Visible fluorescent proteins (VFPs) for FRET studies, a comprehensive table with Förster radii of VFP pairs is presented and recommendations for choosing the right pairs are made. The chapter discusses VFPs that are used for studies that use fluorescence resonance

  10. Fluorescent Proteins for Flow Cytometry.

    Science.gov (United States)

    Hawley, Teresa S; Hawley, Robert G; Telford, William G

    2017-04-03

    Fluorescent proteins have become standard tools for cell and molecular biologists. The color palette of fluorescent proteins spans the ultraviolet, visible, and near-infrared spectrum. Utility of fluorescent proteins has been greatly facilitated by the availability of compact and affordable solid state lasers capable of providing various excitation wavelengths. In theory, the plethora of fluorescent proteins and lasers make it easy to detect multiple fluorescent proteins simultaneously. However, in practice, heavy spectral overlap due to broad excitation and emission spectra presents a challenge. In conventional flow cytometry, careful selection of excitation wavelengths and detection filters is necessary. Spectral flow cytometry, an emerging methodology that is not confined by the "one color, one detector" paradigm, shows promise in the facile detection of multiple fluorescent proteins. This chapter provides a synopsis of fluorescent protein development, a list of commonly used fluorescent proteins, some practical considerations and strategies for detection, and examples of applications. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  11. Fluorescence Spectra of Highlighter Inks

    Science.gov (United States)

    Birriel, Jennifer J.; King, Damon

    2018-01-01

    Fluorescence spectra excited by laser pointers have been the subject of several papers in "TPT". These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by…

  12. Coordination Chemistry of Linear Oligopyrrolic Fragments Inspired by Heme Metabolites

    Science.gov (United States)

    Gautam, Ritika

    Linear oligopyrroles are degradation products of heme, which is converted in the presence of heme oxygenase to bile pigments, such as biliverdin and bilirubin. These tetrapyrrolic oligopyrroles are ubiquitously present in biological systems and find applications in the fields of catalysis and sensing. These linear tetrapyrrolic scaffolds are further degraded into linear tripyrrolic and dipyrrolic fragments. Although these lower oligopyrroles are abundantly present, their coordination chemistry requires further characterization. This dissertation focuses mainly on two classes of bioinspired linear oligopyrroles, propentdyopent and tripyrrindione, and their transition metal complexes, which present a rich ligand-based redox chemistry. Chapter 1 offers an overview of heme degradation to different classes of linear oligopyrroles and properties of their transition metal complexes. Chapter 2 is focused on the tripyrrin-1,14-dione scaffold of the urinary pigment uroerythrin, which coordinates divalent transition metals palladium and copper with square planar geometry. Specifically, the tripyrrin-1, 14-dione ligand binds Cu(II) and Pd(II) as a dianionic organic radical under ambient conditions. The electrochemical study confirms the presence of ligand based redox chemistry, and one electron oxidation or reduction reactions do not alter the planar geometry around the metal center. The X-Ray analysis and the electron paramagnetic resonance (EPR) studies of the complexes in the solid and solution phase reveals intermolecular interactions between the ligand based unpaired electrons and therefore formation of neutral pi-pi dimers. In Chapter 3, the antioxidant activity and the fluorescence sensor properties of the tripyrrin-1,14-dione ligand in the presence of superoxide are described. We found that the tripyrrindione ligand undergoes one-electron reduction in the presence of the superoxide radical anion (O2•- ) to form highly fluorescent H3TD1•- radical anion, which emits

  13. Cantilever torque magnetometry on coordination compounds

    DEFF Research Database (Denmark)

    Perfetti, Mauro

    2017-01-01

    Cantilever Torque Magnetometry (CTM) is one of the leading techniques to deeply understand magnetic anisotropy of coordination compounds. The knowledge of magnetic anisotropy is a mandatory requirement before proceeding with any future application related to the magnetic properties of coordination...

  14. Fluorescence calibration method for single-particle aerosol fluorescence instruments

    Science.gov (United States)

    Shipley Robinson, Ellis; Gao, Ru-Shan; Schwarz, Joshua P.; Fahey, David W.; Perring, Anne E.

    2017-05-01

    Real-time, single-particle fluorescence instruments used to detect atmospheric bioaerosol particles are increasingly common, yet no standard fluorescence calibration method exists for this technique. This gap limits the utility of these instruments as quantitative tools and complicates comparisons between different measurement campaigns. To address this need, we have developed a method to produce size-selected particles with a known mass of fluorophore, which we use to calibrate the fluorescence detection of a Wideband Integrated Bioaerosol Sensor (WIBS-4A). We use mixed tryptophan-ammonium sulfate particles to calibrate one detector (FL1; excitation = 280 nm, emission = 310-400 nm) and pure quinine particles to calibrate the other (FL2; excitation = 280 nm, emission = 420-650 nm). The relationship between fluorescence and mass for the mixed tryptophan-ammonium sulfate particles is linear, while that for the pure quinine particles is nonlinear, likely indicating that not all of the quinine mass contributes to the observed fluorescence. Nonetheless, both materials produce a repeatable response between observed fluorescence and particle mass. This procedure allows users to set the detector gains to achieve a known absolute response, calculate the limits of detection for a given instrument, improve the repeatability of the instrumental setup, and facilitate intercomparisons between different instruments. We recommend calibration of single-particle fluorescence instruments using these methods.

  15. 45 CFR 1310.23 - Coordinated transportation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Coordinated transportation. 1310.23 Section 1310... START PROGRAM HEAD START TRANSPORTATION Special Requirements § 1310.23 Coordinated transportation. (a) Each agency providing transportation services must make reasonable efforts to coordinate transportation...

  16. 78 FR 44519 - Forest Resource Coordinating Committee

    Science.gov (United States)

    2013-07-24

    ... Office of the Secretary Forest Resource Coordinating Committee AGENCY: Forest Service, USDA. ACTION: Notice; Re-establishment of the Forest Resource Coordinating Committee and call for nominations. SUMMARY: The Department of Agriculture re-established the Forest Resource Coordinating Committee (Committee...

  17. 78 FR 34035 - Forest Resource Coordinating Committee

    Science.gov (United States)

    2013-06-06

    ... Forest Service Forest Resource Coordinating Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Forest Resource Coordinating Committee will meet via teleconference every month on... conference call will be posted to the Forest Resource Coordinating Committee Web site, http://www.fs.fed.us...

  18. A Dynamic Coordination Mechanism Using Adjustable Autonomy

    NARCIS (Netherlands)

    Vecht, B. van der; Dignum, F.; Meyer, J.J.C.; Neef, R.M.

    2007-01-01

    Agents in an organization need to coordinate their actions in order to reach the organizational goals. This research describes the relation between types of coordination and the autonomy of actors. In an experimental setting we show that there is not one best way to coordinate in all situations. The

  19. A Dynamic Coordination Mechanism Using Adjustable Autonomy

    NARCIS (Netherlands)

    Neef, R.M.; Vecht, B. van der; Dignum, F.; Meyer, J.J.C.

    2008-01-01

    Agents in an organization need to coordinate their actions in order to reach the organizational goals. This research describes the relation between types of coordination and the autonomy of actors. In an experimental setting we show that there is not one best way to coordinate in all situations. The

  20. Is fiscal policy coordination in EMU desirable?

    NARCIS (Netherlands)

    Beetsma, R.M.W.J.; Debrun, X.; Klaassen, F.J.G.M.

    2001-01-01

    'It is widely argued that Europe's unified monetary policy calls for international coordination of fiscal policy. This paper surveys the issues involved with the coordination of fiscal policies as a demand management tool. We discuss ex-ante and ex-post coordination. The former operates through

  1. 36 CFR 13.1104 - Coordinates.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Coordinates. 13.1104 Section 13.1104 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Administrative Provisions § 13.1104 Coordinates. All coordinates referenced in this subpart use horizontal datum...

  2. Coordination Programming of Photofunctional Molecules

    Directory of Open Access Journals (Sweden)

    Hiroshi Nishihara

    2013-04-01

    Full Text Available Our recent achievements relating to photofunctional molecules are addressed. Section 1 discloses a new concept of photoisomerization. Pyridylpyrimidine-copper complexes undergo a ring inversion that can be modulated by the redox state of the copper center. In combination with an intermolecular photoelectron transfer (PET initiated by the metal-to-ligand charge transfer (MLCT transition of the Cu(I state, we realize photonic regulation of the ring inversion. Section 2 reports on the first examples of heteroleptic bis(dipyrrinatozinc(II complexes. Conventional homoleptic bis(dipyrrinatozinc(II complexes suffered from low fluorescence quantum yields, whereas the heteroleptic ones feature bright fluorescence even in polar solvents. Section 3 describes our new findings on Pechmann dye, which was first synthesized in 1882. New synthetic procedures for Pechmann dye using dimethyl bis(arylethynylfumarate as a starting material gives rise to its new structural isomer. We also demonstrate potentiality of a donor-acceptor-donor type of Pechmann dye in organic electronics.

  3. Coordination of multiple robot arms

    Science.gov (United States)

    Barker, L. K.; Soloway, D.

    1987-01-01

    Kinematic resolved-rate control from one robot arm is extended to the coordinated control of multiple robot arms in the movement of an object. The structure supports the general movement of one axis system (moving reference frame) with respect to another axis system (control reference frame) by one or more robot arms. The grippers of the robot arms do not have to be parallel or at any pre-disposed positions on the object. For multiarm control, the operator chooses the same moving and control reference frames for each of the robot arms. Consequently, each arm then moves as though it were carrying out the commanded motions by itself.

  4. Application coordination in pervasive systems

    CERN Document Server

    Majuntke, Verena Elisabeth

    2013-01-01

    Pervasive applications are designed to support users in their daily life. For this purpose, applications interact with their environment, i.e. their context. They are able to adapt themselves to context changes or to explicitly change the context via actuators. If multiple applications are executed in the same context, interferences are likely to occur. To manage interferences, a coordination framework is presented in this thesis. Interferences are detected using a context model and information about applications' interaction with the context. The resolution of interference is achieved through

  5. Coordinated hybrid automatic repeat request

    KAUST Repository

    Makki, Behrooz

    2014-11-01

    We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users\\' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of M retransmissions and single transmit/receive antennas, the diversity gain of a user increases from M to (J+1)(M-1)+1 where J is the number of users helping that user.

  6. Single Molecule Spectroscopy of Fluorescent Proteins

    NARCIS (Netherlands)

    Blum, Christian; Subramaniam, Vinod

    2009-01-01

    The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject to intense research. Understanding the

  7. Single-molecule spectroscopy of fluorescent proteins

    NARCIS (Netherlands)

    Blum, Christian; Subramaniam, Vinod

    The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject to intense research. Understanding the

  8. A Strategic Design of an Opto-Chemical Security Device with Resettable and Reconfigurable Password Based Upon Dual Channel Two-in-One Chemosensor Molecule

    Science.gov (United States)

    Majumdar, Tapas; Haldar, Basudeb; Mallick, Arabinda

    2017-02-01

    A simple strategy is proposed to design and develop an intelligent device based on dual channel ion responsive spectral properties of a commercially available molecule, harmine (HM). The system can process different sets of opto-chemical inputs generating different patterns as fluorescence outputs at specific wavelengths which can provide an additional level of protection exploiting both password and pattern recognitions. The proposed system could have the potential to come up with highly secured combinatorial locks at the molecular level that could pose valuable real time and on-site applications for user authentication.

  9. Geometrical product specifications. Datums and coordinate systems

    Science.gov (United States)

    Glukhov, V. I.; Ivleva, I. A.; Zlatkina, O. Y.

    2017-06-01

    The work is devoted to the relevant topic such as the technical products quality improvement due to the geometrical specifications accuracy. The research purpose is to ensure the quality indicators on the basis of the systematic approach to the values normalization and geometrical specifications accuracy in the workpiece coordinate systems in the process of design. To achieve the goal two tasks are completed such as the datum features classification according to the number of linear and angular freedom degrees constraints, called the datums informativeness, and the rectangular coordinate systems identification, materialized by workpiece datums sets. The datum features informativeness characterizes the datums functional purpose to limit product workpiece linear and angular degrees of freedom. The datum features informativeness numerically coincides with the kinematic pairs classes and couplings in mechanics. The datum features informativeness identifies the coordinate system without the location redundancy. Each coordinate plane of a rectangular coordinate system has different informativeness 3 + 2 + 1. Each coordinate axis also has different informativeness 4+2+Θ (zero). It is possible to establish the associated workpiece position with three linear and three angular coordinates relative to two axes with the informativeness 4 and 2. is higher, the more informativeness of the coordinate axis or a coordinate plane is, the higher is the linear and angular coordinates accuracy, the coordinate being plotted along the coordinate axis or plane. The systematic approach to the geometrical products specifications positioning in coordinate systems is the scientific basis for a natural transition to the functional dimensions of features position - coordinating dimensions and the size of the features form - feature dimensions of two measures: linear and angular ones. The products technical quality improving is possible due to the coordinate systems introduction materialized by

  10. High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers

    Energy Technology Data Exchange (ETDEWEB)

    Schellenberger, Pascale [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Kaufmann, Rainer [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Siebert, C. Alistair; Hagen, Christoph [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Wodrich, Harald [Microbiologie Fondamentale et Pathogénicité, MFP CNRS UMR 5234, University of Bordeaux SEGALEN, 146 rue Leo Seignat, 33076 Bordeaux (France); Grünewald, Kay, E-mail: kay@strubi.ox.ac.uk [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

    2014-08-01

    Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. - Highlights: • Vitrified mammalian cell were imaged by fluorescence and electron cryo microscopy. • TetraSpeck fluorescence markers were added to correct shifts between cryo fluorescence channels. • FluoSpheres fiducials were used as reference points to assign new coordinates to cryoEM images. • Adenovirus particles were localised with an average correlation precision of 63 nm.

  11. Astroglial networks promote neuronal coordination.

    Science.gov (United States)

    Chever, Oana; Dossi, Elena; Pannasch, Ulrike; Derangeon, Mickael; Rouach, Nathalie

    2016-01-12

    Astrocytes interact with neurons to regulate network activity. Although the gap junction subunits connexin 30 and connexin 43 mediate the formation of extensive astroglial networks that cover large functional neuronal territories, their role in neuronal synchronization remains unknown. Using connexin 30- and connexin 43-deficient mice, we showed that astroglial networks promoted sustained population bursts in hippocampal slices by setting the basal active state of neurons. Astroglial networks limited excessive neuronal depolarization induced by spontaneous synaptic activity, increased neuronal release probability, and favored the recruitment of neurons during bursting, thus promoting the coordinated activation of neuronal networks. In vivo, this sustained neuronal coordination translated into increased severity of acutely evoked epileptiform events and convulsive behavior. These results revealed that connexin-mediated astroglial networks synchronize bursting of neuronal assemblies, which can exacerbate pathological network activity and associated behavior. Our data thus provide molecular and biophysical evidence predicting selective astroglial gap junction inhibitors as anticonvulsive drugs. Copyright © 2016, American Association for the Advancement of Science.

  12. Fluorescent and colorimetric ion probes based on conjugated oligopyrroles.

    Science.gov (United States)

    Ding, Yubin; Tang, Yunyu; Zhu, Weihong; Xie, Yongshu

    2015-03-07

    Metal ions and anions play important roles in many industrial and biochemical processes, and thus it is highly desired to detect them in the relevant systems. Small organic molecule based sensors for selective and sensitive detection of target ions show the advantages of low cost, high sensitivity and convenient implementation. In this area, pyrrole has incomparable advantages. It can be easily incorporated into linear and macrocyclic conjugated structures such as dipyrrins, porphyrins, and N-confused porphyrins, which may utilize the imino N and amino NH moieties for binding metal ions and anions, respectively. In this tutorial review, we focus on representative examples to describe the design, syntheses, sensing mechanisms, and applications of the conjugated oligopyrroles. These compounds could be used as colorimetric or fluorescent ion probes, with the advantages of vivid colour and fluorescence changes, easy structural modification and functionalization, and tunable emission wavelengths. Compared with normal porphyrins, simple di- and tripyrrins, as well as some porphyrinoids are more suitable for designing fluorescence "turn-on" metal probes, because they may exhibit flexible confirmations, and metal coordination will improve the rigidity, resulting in vivid fluorescence enhancement. It is noteworthy that the oligopyrrolic moieties may simultaneously act as the binding unit as well as the reporting moiety, which simplifies the design and syntheses of the probes.

  13. Laser Scanning Fluorescence Microscope

    Science.gov (United States)

    Hansen, Eric W.; Zelten, J. Peter; Wiseman, Benjamin A.

    1988-06-01

    We report on the development of a laser scanning fluorescence microscope possessing several features which facilitate its application to biological and biophysical analyses in living cells. It is built around a standard inverted microscope stand, enabling the use of standard optics, micromanipulation apparatus, and conventional (including video) microscopy in conjunction with laser scanning. The beam is scanned across the specimen by a pair of galvanometer-mounted mirrors, driven by a programmable controller which can operate in three modes: full raster scan, region of interest, and random-access. A full 512x512 pixel image can be acquired in one second. In region of interest mode, several subareas of the field can be selected for more rapid or detailed analysis. For those cases where the time scale of the observed phenomenon precludes full-field imaging, or where a full-field image is unnecessary, the random access mode enables an arbitrary pattern of isolated points to be selected and rapidly sequenced through. Via a graphical user interface implemented on the system's host computer, a user will be able to take a scout image either with video or a full-field laser scan, select regions or points on the scout image with a mouse, and set up experimental parameters such as detector integration times with a window-style menu. The instrument is designed to be a flexible testbed for investigating new techniques, without compromising its utility as a tool for biological research.

  14. Fluorescent labelling in living cells.

    Science.gov (United States)

    Schneider, Anselm Fabian Lowell; Hackenberger, Christian Peter Richard

    2017-12-01

    The labelling of proteins with green fluorescent protein enabled the visualization of proteins in living cells for the first time. Since then, much progress has been made in the field. Modern strategies allow the labelling of proteins in live cells through a range of specialized methods with sophisticated chemical probes that show enhanced photophysical properties compared to fluorescent proteins. This review briefly summarizes recent advances in the field of fluorescent chemical protein labelling inside living cells and illustrates key aspects on the requirements and advantages of each given method. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Coordinate transformation based cryo-correlative methods for electron tomography and focused ion beam milling.

    Science.gov (United States)

    Fukuda, Yoshiyuki; Schrod, Nikolas; Schaffer, Miroslava; Feng, Li Rebekah; Baumeister, Wolfgang; Lucic, Vladan

    2014-08-01

    Correlative microscopy allows imaging of the same feature over multiple length scales, combining light microscopy with high resolution information provided by electron microscopy. We demonstrate two procedures for coordinate transformation based correlative microscopy of vitrified biological samples applicable to different imaging modes. The first procedure aims at navigating cryo-electron tomography to cellular regions identified by fluorescent labels. The second procedure, allowing navigation of focused ion beam milling to fluorescently labeled molecules, is based on the introduction of an intermediate scanning electron microscopy imaging step to overcome the large difference between cryo-light microscopy and focused ion beam imaging modes. These methods make it possible to image fluorescently labeled macromolecular complexes in their natural environments by cryo-electron tomography, while minimizing exposure to the electron beam during the search for features of interest. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Fluorescence lifetime imaging microscopy (FLIM).

    NARCIS (Netherlands)

    van Munster, E.B.; Gadella, Th.W.J.; Rietdorf, J.

    2005-01-01

    Fluorescence lifetime imaging microscopy (FLIM) is a technique to map the spatial distribution of nanosecond excited state lifetimes within microscopic images. FLIM systems have been implemented both in the frequency domain, using sinusoidally intensity-modulated excitation light and modulated

  17. Advanced Methods in Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Luke Fritzky

    2013-01-01

    Full Text Available It requires a good deal of will power to resist hyperbole in considering the advances that have been achieved in fluorescence microscopy in the last 25 years. Our effort has been to survey the modalities of microscopic fluorescence imaging available to cell biologists and perhaps useful for diagnostic pathologists. The gamut extends from established confocal laser scanning through multiphoton and TIRF to the emerging technologies of super-resolution microscopy that breech the Abbé limit of resolution. Also considered are the recent innovations in structured and light sheet illumination, the use of FRET and molecular beacons that exploit specific characteristics of designer fluorescent proteins, fluorescence speckles, and second harmonic generation for native anisometric structures like collagen, microtubules and sarcomeres.

  18. Coordination control of distributed systems

    CERN Document Server

    Villa, Tiziano

    2015-01-01

    This book describes how control of distributed systems can be advanced by an integration of control, communication, and computation. The global control objectives are met by judicious combinations of local and nonlocal observations taking advantage of various forms of communication exchanges between distributed controllers. Control architectures are considered according to  increasing degrees of cooperation of local controllers:  fully distributed or decentralized control,  control with communication between controllers,  coordination control, and multilevel control.  The book covers also topics bridging computer science, communication, and control, like communication for control of networks, average consensus for distributed systems, and modeling and verification of discrete and of hybrid systems. Examples and case studies are introduced in the first part of the text and developed throughout the book. They include: control of underwater vehicles, automated-guided vehicles on a container terminal, contro...

  19. Coordinated Exploration for Grand Challenges

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph

    2016-01-01

    on the acceptance and support of important stakeholders. In this study, we suggest that search consortia are more likely to receive funding when they include representatives of stakeholder concerns, so-called advocacy groups. We extend theory on coordinated exploration in joint search by integrating mechanisms from...... stakeholder theory and argue that advocacy groups improve the generation of potential solutions and provide legitimacy. We test our theory with a unique dataset of 35,249 consortia that proposed solutions to 2,349 grand challenge problems as part of a large European funding program. Our results show...... that advocacy groups benefit search consortia, particularly when consortia exhibit a high dispersion of technological knowledge and when they are inexperienced....

  20. Coordination Frictions and Job Heterogeneity

    DEFF Research Database (Denmark)

    Kennes, John; le Maire, Christian Daniel

    This paper develops and extends a dynamic, discrete time, job to worker matching model in which jobs are heterogeneous in equilibrium. The key assumptions of this economic environment are (i) matching is directed and (ii) coordination frictions lead to heterogeneous local labor markets. We de- rive...... a number of new theoretical results, which are essential for the empirical application of this type of model to matched employer-employee microdata. First, we o¤er a robust equilibrium concept in which there is a continu- ous dispersion of job productivities and wages. Second, we show that our model can...... be readily solved with continuous exogenous worker heterogene- ity, where high type workers (high outside options and productivity) earn higher wages in high type jobs and are hired at least as frequently to the better job types as low type workers (low outside options and productivity). Third, we...

  1. Genetically Encoded Fluorescent Redox Probes

    OpenAIRE

    Hui-Wang Ai; Wei Ren

    2013-01-01

    Redox processes are involved in almost every cell of the body as a consequence of aerobic life. In the past decades, redox biology has been increasingly recognized as one of the key themes in cell signaling. The progress has been accelerated by development of fluorescent probes that can monitor redox conditions and dynamics in cells and cell compartments. This short paper focuses on fluorescent redox probes that are genetically encoded, and discusses their properties, molecular mechanism, adv...

  2. Fluorescence axial nanotomography with plasmonics.

    Science.gov (United States)

    Cade, Nicholas I; Fruhwirth, Gilbert O; Krasavin, Alexey V; Ng, Tony; Richards, David

    2015-01-01

    We present a novel imaging technique with super-resolution axial sensitivity, exploiting the changes in fluorescence lifetime above a plasmonic substrate. Using conventional confocal fluorescence lifetime imaging, we show that it is possible to deliver down to 6 nm axial position sensitivity of fluorophores in whole biological cell imaging. We employ this technique to map the topography of the cellular membrane, and demonstrate its application in an investigation of receptor-mediated endocytosis in carcinoma cells.

  3. X-ray fluorescence holography

    CERN Document Server

    Hayashi, K; Takahashi, Y

    2003-01-01

    X-ray fluorescence holography (XFH) is a new structural analysis method of determining a 3D atomic arrangement around fluorescing atoms. We developed an XFH apparatus using advanced X-ray techniques and succeeded in obtaining high-quality hologram data. Furthermore, we introduced applications to the structural analysis of a thin film and the environment around dopants and, discussed the quantitative analysis of local lattice distortion. (author)

  4. Light Sheet Fluorescence Microscopy (LSFM)

    OpenAIRE

    Adams, Michael W.; Loftus, Andrew F.; Dunn, Sarah E.; Joens, Matthew S.; Fitzpatrick, James A. J.

    2015-01-01

    The development of confocal microscopy techniques introduced the ability to optically section fluorescent samples in the axial dimension, perpendicular to the image plane. These approaches, via the placement of a pinhole in the conjugate image plane, provided superior resolution in the axial (z) dimension resulting in nearly isotropic optical sections. However, increased axial resolution, via pinhole optics, comes at the cost of both speed and excitation efficiency. Light Sheet Fluorescent Mi...

  5. Vertical jump coordination: fatigue effects.

    Science.gov (United States)

    Rodacki, André Luiz Felix; Fowler, Neil E; Bennett, Simon J

    2002-01-01

    The aim of this study was to investigate the segmental coordination of vertical jumps under fatigue of the knee extensor and flexor muscles. Eleven healthy and active subjects performed maximal vertical jumps with and without fatigue, which was imposed by requesting the subjects to extend/flex their knees continuously in a weight machine, until they could not lift a load corresponding to approximately 50% of their body weight. Knee extensor and flexor isokinetic peak torques were also measured before and after fatigue. Video, ground reaction forces, and electromyographic data were collected simultaneously and used to provide several variables of the jumps. Fatiguing the knee flexor muscles did not reduce the height of the jumps or induce changes in the kinematic, kinetic, and electromyographic profiles. Knee extensor fatigue caused the subjects to adjust several variables of the movement, in which the peak joint angular velocity, peak joint net moment, and power around the knee were reduced and occurred earlier in comparison with the nonfatigued jumps. The electromyographic data analyses indicated that the countermovement jumps were performed similarly, i.e., a single strategy was used, irrespective of which muscle group (extensor or flexors) or the changes imposed on the muscle force-generating characteristics (fatigue or nonfatigue). The subjects executed the movements as if they scaled a robust template motor program, which guided the movement execution in all jump conditions. It was speculated that training programs designed to improve jump height performance should avoid severe fatigue levels, which may cause the subjects to learn and adopt a nonoptimal and nonspecific coordination solution. It was suggested that the neural input used in the fatigued condition did not constitute an optimal solution and may have played a role in decreasing maximal jump height achievement.

  6. Coordinating towards a Common Good

    Science.gov (United States)

    Santos, Francisco C.; Pacheco, Jorge M.

    2010-09-01

    Throughout their life, humans often engage in collective endeavors ranging from family related issues to global warming. In all cases, the tragedy of the commons threatens the possibility of reaching the optimal solution associated with global cooperation, a scenario predicted by theory and demonstrated by many experiments. Using the toolbox of evolutionary game theory, I will address two important aspects of evolutionary dynamics that have been neglected so far in the context of public goods games and evolution of cooperation. On one hand, the fact that often there is a threshold above which a public good is reached [1, 2]. On the other hand, the fact that individuals often participate in several games, related to the their social context and pattern of social ties, defined by a social network [3, 4, 5]. In the first case, the existence of a threshold above which collective action is materialized dictates a rich pattern of evolutionary dynamics where the direction of natural selection can be inverted compared to standard expectations. Scenarios of defector dominance, pure coordination or coexistence may arise simultaneously. Both finite and infinite population models are analyzed. In networked games, cooperation blooms whenever the act of contributing is more important than the effort contributed. In particular, the heterogeneous nature of social networks naturally induces a symmetry breaking of the dilemmas of cooperation, as contributions made by cooperators may become contingent on the social context in which the individual is embedded. This diversity in context provides an advantage to cooperators, which is particularly strong when both wealth and social ties follow a power-law distribution, providing clues on the self-organization of social communities. Finally, in both situations, it can be shown that individuals no longer play a defection dominance dilemma, but effectively engage in a general N-person coordination game. Even if locally defection may seem

  7. Design Strategies for Fluorescent Biodegradable Polymeric Biomaterials.

    Science.gov (United States)

    Zhang, Yi; Yang, Jian

    2013-01-14

    The marriage of biodegradable polymer and fluorescent imaging has resulted in an important area of polymeric biomaterials: biodegradable fluorescent polymers. Researchers have put significant efforts on developing versatile fluorescent biomaterials due to their promising in biological/biomedical labeling, tracking, monitoring, imaging, and diagnostic applications, especially in drug delivery, tissue engineering, and cancer imaging applications. Biodegradable fluorescent polymers can function not only as implant biomaterials but also as imaging probes. Currently, there are two major classes of biodegradable polymers used as fluorescent materials. The first class is the combination of non-fluorescent biodegradable polymers and fluorescent agents such as organic dyes and quantum dots. Another class of polymers shows intrinsic photoluminescence as polymers by themselves carrying integral fluorescent chemical structures in or pendent to their polymer backbone, such as Green Fluorescent protein (GFP), and the recently developed biodegradable photoluminescent polymer (BPLP). Thus there is no need to conjugate or encapsulate additional fluorescent materials for the latter. In the present review, we will review the fluorescent biodegradable polymers with emphases on material fluorescence mechanism, design criteria for fluorescence, and their cutting-edge applications in biomedical engineering. We expect that this review will provide insightful discussion on the fluorescent biomaterial design and lead to innovations for the development of the next generation of fluorescent biomaterials and fluorescence-based biomedical technology.

  8. Design Strategies for Fluorescent Biodegradable Polymeric Biomaterials

    OpenAIRE

    Zhang, Yi; Yang, Jian

    2012-01-01

    The marriage of biodegradable polymer and fluorescent imaging has resulted in an important area of polymeric biomaterials: biodegradable fluorescent polymers. Researchers have put significant efforts on developing versatile fluorescent biomaterials due to their promising in biological/biomedical labeling, tracking, monitoring, imaging, and diagnostic applications, especially in drug delivery, tissue engineering, and cancer imaging applications. Biodegradable fluorescent polymers can function ...

  9. Design Strategies for Fluorescent Biodegradable Polymeric Biomaterials

    Science.gov (United States)

    Zhang, Yi; Yang, Jian

    2013-01-01

    The marriage of biodegradable polymer and fluorescent imaging has resulted in an important area of polymeric biomaterials: biodegradable fluorescent polymers. Researchers have put significant efforts on developing versatile fluorescent biomaterials due to their promising in biological/biomedical labeling, tracking, monitoring, imaging, and diagnostic applications, especially in drug delivery, tissue engineering, and cancer imaging applications. Biodegradable fluorescent polymers can function not only as implant biomaterials but also as imaging probes. Currently, there are two major classes of biodegradable polymers used as fluorescent materials. The first class is the combination of non-fluorescent biodegradable polymers and fluorescent agents such as organic dyes and quantum dots. Another class of polymers shows intrinsic photoluminescence as polymers by themselves carrying integral fluorescent chemical structures in or pendent to their polymer backbone, such as Green Fluorescent protein (GFP), and the recently developed biodegradable photoluminescent polymer (BPLP). Thus there is no need to conjugate or encapsulate additional fluorescent materials for the latter. In the present review, we will review the fluorescent biodegradable polymers with emphases on material fluorescence mechanism, design criteria for fluorescence, and their cutting-edge applications in biomedical engineering. We expect that this review will provide insightful discussion on the fluorescent biomaterial design and lead to innovations for the development of the next generation of fluorescent biomaterials and fluorescence-based biomedical technology. PMID:23710326

  10. Fluorescent retroreflective signing of work zones : abstract

    NARCIS (Netherlands)

    Vos, A.P. de; Horst, A.R.A. van der; Alferdinck, J.W.A.M.; Kooi, F.L.

    1999-01-01

    Fluorescent retroreflective materials increase the brightness of traffic signs. In construction work zones a benefit is expected from the increased conspicuity of fluorescent retroreflective signs. Fluorescent material can be used instead of non-fluorescent materials both for the advance warning

  11. 21 CFR 892.1220 - Fluorescent scanner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fluorescent scanner. 892.1220 Section 892.1220...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1220 Fluorescent scanner. (a) Identification. A fluorescent scanner is a device intended to measure the induced fluorescent radiation in the body by exposing...

  12. Control coordination abilities in shock combat sports

    Directory of Open Access Journals (Sweden)

    Natalya Boychenko

    2014-12-01

    Full Text Available Purpose: optimize the process control level of coordination abilities in martial arts. Material and Methods: analysis and compilation of scientific and methodological literature, interviews with coaches of drum martial arts, video analysis techniques, teacher observations. Results: identified specific types of coordination abilities in shock combat sports. Pod branny and offered specific and nonspecific tests to monitor the level of species athletes coordination abilities. Conclusion: it is determined that in order to achieve victory in the fight martial artists to navigate the space to be able to assess and manage dynamic and spatio-temporal parameters of movements, maintain balance, have a high coordination of movements. The proposed tests to monitor species coordination abilities athletes allow an objective assessment of not only the overall level of coordination, and the level of specific types of manifestations of this ability.

  13. Knowledge coordination in distributed software management

    DEFF Research Database (Denmark)

    Persson, John Stouby; Mathiassen, Lars

    2012-01-01

    Software organizations are increasingly relying on cross-organizational and cross-border collaboration, requiring effective coordination of distributed knowledge. However, such coordination is challenging due to spatial separation, diverging communities-of-practice, and unevenly distributed...... communication breakdowns on recordings of their combined teleconferencing and real-time collaborative modeling. As a result, we offer theoretical propositions that explain how distributed software managers can deal with communication breakdowns and effectively coordinate knowledge through multimodal virtual...

  14. Collaborative Supply Chain Planning and Coordination

    DEFF Research Database (Denmark)

    Wong, Chee Yew

    generalizes their key findings, insights, and implications to theory and practice. The thesis concludes several theoretical frameworks and contributions to the theory of responsiveness and supply chain coordination. The thesis begins with analyzing four different responsiveness strategies – differentiating...... processes, particularly the behaviour of risk-taking/avoidance, conflict resolutions, and self-interest. All these lead to conclusion of five propositions or principles of supply chain coordination, and the theory of coordination process and behaviour. Combining the propositions of responsiveness...

  15. Convergence of barycentric coordinates to barycentric kernels

    KAUST Repository

    Kosinka, Jiří

    2016-02-12

    We investigate the close correspondence between barycentric coordinates and barycentric kernels from the point of view of the limit process when finer and finer polygons converge to a smooth convex domain. We show that any barycentric kernel is the limit of a set of barycentric coordinates and prove that the convergence rate is quadratic. Our convergence analysis extends naturally to barycentric interpolants and mappings induced by barycentric coordinates and kernels. We verify our theoretical convergence results numerically on several examples.

  16. Surface Coordination Chemistry of Metal Nanomaterials.

    Science.gov (United States)

    Liu, Pengxin; Qin, Ruixuan; Fu, Gang; Zheng, Nanfeng

    2017-02-15

    Surface coordination chemistry of nanomaterials deals with the chemistry on how ligands are coordinated on their surface metal atoms and influence their properties at the molecular level. This Perspective demonstrates that there is a strong link between surface coordination chemistry and the shape-controlled synthesis, and many intriguing surface properties of metal nanomaterials. While small adsorbates introduced in the synthesis can control the shapes of metal nanocrystals by minimizing their surface energy via preferential coordination on specific facets, surface ligands properly coordinated on metal nanoparticles readily promote their catalysis via steric interactions and electronic modifications. The difficulty in the research of surface coordination chemistry of nanomaterials mainly lies in the lack of effective tools to characterize their molecular surface coordination structures. Also highlighted are several model material systems that facilitate the characterizations of surface coordination structures, including ultrathin nanostructures, atomically precise metal nanoclusters, and atomically dispersed metal catalysts. With the understanding of surface coordination chemistry, the molecular mechanisms behind various important effects (e.g., promotional effect of surface ligands on catalysis, support effect in supported metal nanocatalysts) of metal nanomaterials are disclosed.

  17. The European NEO Coordination Centre

    Science.gov (United States)

    Perozzi, E.; Borgia, B.; Micheli, M.

    An operational approach to NEO (Near-Earth Object) hazard monitoring has been developed at European level within the framework of the Space Situational Awareness Program (SSA) of the European Space Agency (ESA). Through federating European assets and profiting of the expertise developed in European Universities and Research Centers, it has been possible to start the deployment of the so-called SSA NEO Segment. This initiative aims to provide a significant contribution to the worldwide effort to the discovery, follow-up and characterization of the near-Earth object population. A major achievement has been the inauguration in May 2013 of the ESA NEO Coordination Centre located at ESRIN (Frascati, Italy). The goal of the NEOCC Precursor Service operations is twofold: to make available updated information on the NEO population and the associated hazard and to contribute to optimize the NEO observational efforts. This is done by maintaining and improving a Web Portal publicly available at http://neo.ssa.esa.int and by performing follow-up observations through a network of collaborating telescopes and facilities. An overview of the SSA-NEO System and a summary of the first two years of NEOCC operations is presented.

  18. Multipoint fluorescence correlation spectroscopy with total internal reflection fluorescence microscope.

    Science.gov (United States)

    Ohsugi, Yu; Kinjo, Masataka

    2009-01-01

    We report simultaneous determination of diffusion coefficients at different points of a cell membrane using a multipoint fluorescence correlation spectroscopy (FCS) system. A system carrying seven detection areas in the evanescent field is achieved by using seven optical fibers on the image plane in the detection port of an objective-type total internal reflection FCS (TIR-FCS) system. Fluctuation of fluorescence intensity is monitored and evaluated using seven photomultiplier tubes (PMTs) and a newly constructed multichannel correlator. We demonstrate simultaneous-multipoint FCS, with a 3-mus time resolution, to investigate heterogeneous structures such as cell membranes and membrane-binding molecular dynamics near glass surfaces in live cells.

  19. Ultrasensitive fluorescence detection of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Mathies, R.A.; Glazer, A.N.

    1992-01-01

    We have shown that a number of polycationic highly fluorescent dyes form complexes with double-stranded DNA (dsDNA) which are stable to electrophoresis and have characterized in detail such dsDNA complexes with TOTO (1,1[prime]-(4,4,7,7-tetramethyl-4,7-diazaundecamethylene)-bis-4-[3-methyl-2,3-dihydro-(benzo-1,3-thiazole)-2-methylidene]-quinolinium tetraiodide) and oxazole yellow dimer (YOYO; an analogue of TOTO with a benzo-1,3-oxazole in place of the benzo-1,3-thiazole). TOTO and YOYO are virtually non-fluorescent in solution, but form highly fluorescent complexes with dsDNA, up to a maximum dye to DNA bp ratio of 1:4, with >1000-fold fluorescence enhancement. We have developed an assay using YOYO for the quantitation of single-stranded and dsDNA in solution applicable over a range of DNA concentrations from 0.5 to 100 ng per ml. The fluorescent dsDNA-dye complexes allow detection of dsDNA on agarose and acrylamide gels with picogram sensitivity. We have applied these complexes in multiplex mapping experiments for accurate sizing and quantitation of restriction fragments. We have shown that in gel shift experiments the stable dsDNA-dye complexes can be used to detect heteroduplex-Muts complexes with a sensitivity comparable to radioisotopic detection.

  20. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan

    2017-05-12

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  1. [Reading by fluorescent lamp light].

    Science.gov (United States)

    Höfling, G

    1979-08-01

    In dioptrics courses it has hitherto been taught that eyes of near-sighted patients who work in fluorescent light should be slightly under-corrected, since the near point is approximated in bluish light as a result of the chromatic aberration of the eye, in contrast to its location in white light or even the reddish light of incandescent lamps. The theory further states that this recommendation does not apply if close-range refraction occurs under fluorescent light. However, this is seldom the case. In our own investigations this approximation of the near point, under uniform illumination by fluorescent strip lights running across the ceiling, did not occur, at least not in "white" light (No. 33). On the contrary, under an incandescent lamp which was only half as powerful the near point was regularly closer to the eye than under white fluorescent light. The recommendation for under-correction of pulpit spectacles computed in incandescent light can therefore no longer be upheld.--While many patients complain of difficulties in diffuse incandescent light, these may be due to several other illumination factors which have not yet been fully investigated.--Some fundamental differences between diffuse fluorescent lighting and incandescent lamp lighting where there is a fall-off in luminosity are described.

  2. Fluorescence and phosphorescence of rutin

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, Stanislav L., E-mail: bondarev@imaph.bas-net.by [Minsk State Higher Radioengineering College, 220005 Minsk (Belarus); Knyukshto, Valeri N. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 220072 Minsk (Belarus)

    2013-10-15

    Rutin is one of the most promising flavonoid from a pharmacological and biochemical point of view. Here we have explored its spectroscopic and photophysical properties at room temperature and 77 K using steady-state absorption-luminescence methods and pulse spectroscopy equipment. By excitation into the absorption band 1 of rutin in methanol at room temperature the normal Stokes' shifted fluorescence with a maximum at 415 nm and quantum yield of 2×10{sup −4} was revealed. However, by excitation into the bands 2 and 3 any emission wasn’t observed. At 77 K in ethanol glass we have observed fluorescence at 410 nm and phosphorescence at 540 nm for the first time. As a result the adequate energetic scheme including the lowest electronic excited singlet at 26000 cm{sup −1} and triplet at 19600 cm{sup −1} states was proposed. -- Highlights: • Rutin fluorescence and phosphorescence at 77 K were revealed for the first time. • Room temperature fluorescence is determined by maximum at 415 nm and yield of 2×10{sup −4}. • Violation of Vavilov–Kasha rule by excitation into the absorption bands 2 and 3. • Fluorescence and phosphorescence in rutin are caused by the allowed π, π{sup (⁎)} transitions.

  3. Plasmonics Enhanced Smartphone Fluorescence Microscopy.

    Science.gov (United States)

    Wei, Qingshan; Acuna, Guillermo; Kim, Seungkyeum; Vietz, Carolin; Tseng, Derek; Chae, Jongjae; Shir, Daniel; Luo, Wei; Tinnefeld, Philip; Ozcan, Aydogan

    2017-05-18

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  4. Vaidya spacetime in the diagonal coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, V. A., E-mail: berezin@inr.ac.ru; Dokuchaev, V. I., E-mail: dokuchaev@inr.ac.ru; Eroshenko, Yu. N., E-mail: eroshenko@inr.ac.ru [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

    2017-03-15

    We have analyzed the transformation from initial coordinates (v, r) of the Vaidya metric with light coordinate v to the most physical diagonal coordinates (t, r). An exact solution has been obtained for the corresponding metric tensor in the case of a linear dependence of the mass function of the Vaidya metric on light coordinate v. In the diagonal coordinates, a narrow region (with a width proportional to the mass growth rate of a black hole) has been detected near the visibility horizon of the Vaidya accreting black hole, in which the metric differs qualitatively from the Schwarzschild metric and cannot be represented as a small perturbation. It has been shown that, in this case, a single set of diagonal coordinates (t, r) is insufficient to cover the entire range of initial coordinates (v, r) outside the visibility horizon; at least three sets of diagonal coordinates are required, the domains of which are separated by singular surfaces on which the metric components have singularities (either g{sub 00} = 0 or g{sub 00} = ∞). The energy–momentum tensor diverges on these surfaces; however, the tidal forces turn out to be finite, which follows from an analysis of the deviation equations for geodesics. Therefore, these singular surfaces are exclusively coordinate singularities that can be referred to as false fire-walls because there are no physical singularities on them. We have also considered the transformation from the initial coordinates to other diagonal coordinates (η, y), in which the solution is obtained in explicit form, and there is no energy–momentum tensor divergence.

  5. Lanthanide Chemistry: From Coordination in Chemical Complexes Shaping Our Technology to Coordination in Enzymes Shaping Bacterial Metabolism.

    Science.gov (United States)

    Martinez-Gomez, Norma Cecilia; Vu, Huong N; Skovran, Elizabeth

    2016-10-17

    Lanthanide chemistry has only been extensively studied for the last 2 decades, when it was recognized that these elements have unusual chemical characteristics including fluorescent and potent magnetic properties because of their unique 4f electrons.1,2 Chemists are rapidly and efficiently integrating lanthanides into numerous compounds and materials for sophisticated applications. In fact, lanthanides are often referred to as "the seeds of technology" because they are essential for many technological devices including smartphones, computers, solar cells, batteries, wind turbines, lasers, and optical glasses.3-6 However, the effect of lanthanides on biological systems has been understudied. Although displacement of Ca 2+ by lanthanides in tissues and enzymes has long been observed,7 only a few recent studies suggest a biological role for lanthanides based on their stimulatory properties toward some plants and bacteria.8,9 Also, it was not until 2011 that the first biochemical evidence for lanthanides as inherent metals in bacterial enzymes was published.10 This forum provides an overview of the classical and current aspects of lanthanide coordination chemistry employed in the development of technology along with the biological role of lanthanides in alcohol oxidation. The construction of lanthanide-organic frameworks will be described. Examples of how the luminescence field is rapidly evolving as more information about lanthanide-metal emissions is obtained will be highlighted, including biological imaging and telecommunications.11 Recent breakthroughs and observations from different exciting areas linked to the coordination chemistry of lanthanides that will be mentioned in this forum include the synthesis of (i) macrocyclic ligands, (ii) antenna molecules, (iii) coordination polymers, particularly nanoparticles, (iv) hybrid materials, and (v) lanthanide fuel cells. Further, the role of lanthanides in bacterial metabolism will be discussed, highlighting the

  6. Correction of X-ray absorption spectra for thickness inhomogeneity and fluorescence of sample

    CERN Document Server

    Babanov, Y A; Miyanaga, T

    2001-01-01

    For thin powder samples, the EXAFS spectra are often tampered due to the thickness inhomogeneity, and, thick samples, due to the fluorescence at energies above the absorption edge. As a result, the EXAFS amplitude decreases and information about the coordination numbers is distorted. To correct the X-ray absorption spectra for inhomogeneity and fluorescence effects, we propose a new method, which comes to solve the inverse problem. Model calculations were carried out. This method is applied to preliminary processing EXAFS spectra for Ni-Mn alloys.

  7. Project Coordinator - Karianet | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The specific responsibilities of the Project Coordinator are grouped into three categories: Knowledge Management, Research Management and Project Management. As Knowledge Manager, the program coordinator will play a lead role in: Introducing and using knowledge management strategies and tools;; Developing ...

  8. Self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2012-01-01

    This paper regards coordination of networked systems with ternary controllers. We develop a hybrid coordination system which implements a self-triggered communication policy, based on polling the neighbors upon need. We prove that the proposed scheme ensures finite-time convergence to a neighborhood

  9. 78 FR 73819 - Forest Resource Coordinating Committee

    Science.gov (United States)

    2013-12-09

    ... Forest Service Forest Resource Coordinating Committee AGENCY: Forest Service, USDA. ACTION: Notice of Cancellation. SUMMARY: The U.S. Department of Agriculture, Forest Service was required to cancel the October 17-18, 2013 meeting of the Forest Resource Coordinating Committee due to the Government partial shutdown...

  10. 78 FR 57128 - Forest Resource Coordinating Committee

    Science.gov (United States)

    2013-09-17

    ... Forest Service Forest Resource Coordinating Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Forest Resource Coordinating Committee Meeting will meet in Rosslyn, Virginia. The... effectively address the national priorities for non-industrial private forest land. The purpose of this...

  11. Coordinated Neuronal Activity Enhances Corticocortical Communication.

    Science.gov (United States)

    Zandvakili, Amin; Kohn, Adam

    2015-08-19

    Relaying neural signals between cortical areas is central to cognition and sensory processing. The temporal coordination of activity in a source population has been suggested to determine corticocortical signaling efficacy, but others have argued that coordination is functionally irrelevant. We reasoned that if coordination significantly influenced signaling, spiking in downstream networks should be preceded by transiently elevated coordination in a source population. We developed a metric to quantify network coordination in brief epochs, and applied it to simultaneous recordings of neuronal populations in cortical areas V1 and V2 of the macaque monkey. Spiking in the input layers of V2 was preceded by brief epochs of elevated V1 coordination, but this was not the case in other layers of V2. Our results indicate that V1 coordination influences its signaling to direct downstream targets, but that coordinated V1 epochs do not propagate through multiple downstream networks as in some corticocortical signaling schemes. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. 20 CFR 631.37 - Coordination activities.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Coordination activities. 631.37 Section 631.37 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR PROGRAMS UNDER TITLE III OF THE JOB TRAINING PARTNERSHIP ACT State Administration § 631.37 Coordination activities. (a...

  13. Redundant internal coordinates, compliance constants and non ...

    Indian Academy of Sciences (India)

    If chosen properly, the internal coordinates will have minimum mixing in the normal mode representation. This can in principle lead to an automation ... It was shown in the literature that the relaxed force constants could be used as a measure of bond order in all atom-atom distance coordinates. Some of the bonded and ...

  14. A coordination language for mobile components

    NARCIS (Netherlands)

    F. Arbab (Farhad); M.M. Bonsangue (Marcello); F.S. de Boer (Frank)

    1999-01-01

    textabstractAbstract In this paper we present the sigmapi coordination language, a core language for specifying dynamic networks of components. The language is inspired by the Manifold coordination language and by the pi-calculus. The main concepts of the language are components,

  15. Coordinating Units at the Candy Depot

    Science.gov (United States)

    Norton, Anderson; Boyce, Steven; Hatch, Jennifer

    2015-01-01

    In general, units coordination refers to the relationships that students can maintain between various units when working within a numerical situation. It is critical that middle school students learn to coordinate three levels of units not only because of their importance in understanding fractions but also because of their implications for…

  16. Block Coordinate Descent Only Converge to Minimizers

    OpenAIRE

    Song, Enbin; Shen, Zhubin; Shi, Qingjiang

    2017-01-01

    Given a non-convex twice continuously differentiable cost function with Lipschitz continuous gradient, we prove that all of block coordinate gradient descent, block mirror descent and proximal block coordinate descent converge to a local minimizer, almost surely with random initialization. Furthermore, we show that these results also hold true even for the cost functions with non-isolated critical points.

  17. Some thoughts about matrix coordinate transformations

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Joke [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: joke.adam@fys.kuleuven.be; Janssen, Bert [Departamento de Fisica Teorica y del Cosmos and Centro Andaluz de Fisica de Particulas Elementales, Universidad de Granada, 18071 Granada (Spain)], E-mail: bjanssen@ugr.es; Troost, Walter [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: walter.troost@fys.kuleuven.be; Herck, Walter van [Instituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: walter.vanherck@fys.kuleuven.be

    2008-04-17

    Matrix coordinate transformations are defined as substitution operators without requiring an ordering prescription or an inclusion function from the Abelian coordinate transformations. We construct transforming objects mimicking most of the properties of tensors. We point out some problems with the matrix generalization of contravariant vectors. We suggest to use the substitution operators to search for an inclusion function.

  18. Distributed Coordination of Household Electricity Consumption

    DEFF Research Database (Denmark)

    Juelsgaard, Morten; Teixeira, Andre; Johansson, Mikael

    2014-01-01

    This work presents a distributed framework for coordination of flexible electricity consumption for a number of households in the distribution grid. We conduct coordination with the purpose of minimizing a trade-off between individual concerns about discomfort and electricity cost, on the one hand...

  19. Unpacking Coordination Benefits in Supply Networks

    DEFF Research Database (Denmark)

    Petrick, Irene J.; Maitland, Carleen; Pogrebnyakov, Nicolai

    2016-01-01

    This paper examines how coordination among firms in supply networks generates benefits in the short and long terms for firms. It focuses on information technology (IT) and process improvement coordination. Analysis was performed on quantitative and qualitative data from a sample of SMEs in plastics......). These results extend the understanding of how participation in supply networks benefits individual firms....

  20. Guidelines for the Practice of Parenting Coordination

    Science.gov (United States)

    American Psychologist, 2012

    2012-01-01

    Parenting coordination is a nonadversarial dispute resolution process that is court ordered or agreed on by divorced and separated parents who have an ongoing pattern of high conflict and/or litigation about their children. These guidelines are designed to address the developing area of practice known as parenting coordination. In response to the…

  1. An Intrinsic Coordinate System for Fingerprint Matching

    NARCIS (Netherlands)

    Bazen, A.M.; Gerez, Sabih H.; Bigun, J.; Smeraldi, F.

    2001-01-01

    In this paper, an intrinsic coordinate system is proposed for fingerprints. First the fingerprint is partitioned in regular regions, which are regions that contain no singular points. In each regular region, the intrinsic coordinate system is defined by the directional field. When using the

  2. Energy Materials Coordinating Committee (EMaCC)

    Energy Technology Data Exchange (ETDEWEB)

    1991-05-31

    This report summarizes EMaCC activities for fiscal year 1990 and describes the materials research programs of various offices and divisions within the department. The DOE Energy Materials Coordinating Committee (EMaCC) serves primarily to enhance coordination among the Department's materials programs and to further the effective use of materials expertise within the department. (JL)

  3. Motor Coordination and Intelligence Level in Adolescents

    Science.gov (United States)

    Planinsec, Jurij; Pisot, Rado

    2006-01-01

    This study investigated the relationship between motor coordination and intelligence level in adolescents. The sample was comprised of 550 adolescents from Slovenia, aged 13.1 years (SD = 0.87), who attended elementary schools. For assessment of motor coordination a battery of eight tests were used. Assessment of intelligence was carried out with…

  4. Acting together: Representations and coordination processes

    DEFF Research Database (Denmark)

    Vesper, Cordula; Sebanz, Natalie

    2016-01-01

    findings from experimental studies that shed light on general coordination strategies, representations of joint abilities and tasks, mechanisms of predicting own and others’ actions, and non-verbal communication through action. We will conclude by discussing ways in which different coordination mechanisms...

  5. You're a "What"? Recycling Coordinator

    Science.gov (United States)

    Torpey, Elka Maria

    2011-01-01

    Recycling coordinators supervise curbside and dropoff recycling programs for municipal governments or private firms. Today, recycling is mandatory in many communities. And advancements in collection and processing methods have helped to increase the quantity of materials for which the recycling coordinator is responsible. In some communities,…

  6. Fluorescence confocal microscopy for pathologists.

    Science.gov (United States)

    Ragazzi, Moira; Piana, Simonetta; Longo, Caterina; Castagnetti, Fabio; Foroni, Monica; Ferrari, Guglielmo; Gardini, Giorgio; Pellacani, Giovanni

    2014-03-01

    Confocal microscopy is a non-invasive method of optical imaging that may provide microscopic images of untreated tissue that correspond almost perfectly to hematoxylin- and eosin-stained slides. Nowadays, following two confocal imaging systems are available: (1) reflectance confocal microscopy, based on the natural differences in refractive indices of subcellular structures within the tissues; (2) fluorescence confocal microscopy, based on the use of fluorochromes, such as acridine orange, to increase the contrast epithelium-stroma. In clinical practice to date, confocal microscopy has been used with the goal of obviating the need for excision biopsies, thereby reducing the need for pathological examination. The aim of our study was to test fluorescence confocal microscopy on different types of surgical specimens, specifically breast, lymph node, thyroid, and colon. The confocal images were correlated to the corresponding histological sections in order to provide a morphologic parallel and to highlight current limitations and possible applications of this technology for surgical pathology practice. As a result, neoplastic tissues were easily distinguishable from normal structures and reactive processes such as fibrosis; the use of fluorescence enhanced contrast and image quality in confocal microscopy without compromising final histologic evaluation. Finally, the fluorescence confocal microscopy images of the adipose tissue were as accurate as those of conventional histology and were devoid of the frozen-section-related artefacts that can compromise intraoperative evaluation. Despite some limitations mainly related to black/white images, which require training in imaging interpretation, this study confirms that fluorescence confocal microscopy may represent an alternative to frozen sections in the assessment of margin status in selected settings or when the conservation of the specimen is crucial. This is the first study to employ fluorescent confocal microscopy on

  7. Genetically Encoded Fluorescent Redox Probes

    Directory of Open Access Journals (Sweden)

    Hui-Wang Ai

    2013-11-01

    Full Text Available Redox processes are involved in almost every cell of the body as a consequence of aerobic life. In the past decades, redox biology has been increasingly recognized as one of the key themes in cell signaling. The progress has been accelerated by development of fluorescent probes that can monitor redox conditions and dynamics in cells and cell compartments. This short paper focuses on fluorescent redox probes that are genetically encoded, and discusses their properties, molecular mechanism, advantages and pitfalls. Our recent work on reaction-based encoded probes that are responsive to particular redox signaling molecules is also reviewed. Future challenges and directions are also commented.

  8. Genetically encoded fluorescent redox probes.

    Science.gov (United States)

    Ren, Wei; Ai, Hui-Wang

    2013-11-11

    Redox processes are involved in almost every cell of the body as a consequence of aerobic life. In the past decades, redox biology has been increasingly recognized as one of the key themes in cell signaling. The progress has been accelerated by development of fluorescent probes that can monitor redox conditions and dynamics in cells and cell compartments. This short paper focuses on fluorescent redox probes that are genetically encoded, and discusses their properties, molecular mechanism, advantages and pitfalls. Our recent work on reaction-based encoded probes that are responsive to particular redox signaling molecules is also reviewed. Future challenges and directions are also commented.

  9. Transfer Equation in General Curvilinear Coordinates

    Science.gov (United States)

    Freimanis, J.

    The differential operator of the monochromatic polarized radiative transfer equation is studied in case of statistically homogeneous turbid medium in Euclidean three-dimensional space, with arbitrary curvilinear coordinate system defined in it. An apparent rotation of the polarization plane along the light ray with respect to the chosen polarization reference plane generally takes place, due to purely geometric reasons. Using methods of tensor analysis, analytic expressions for the differential operator of the transfer equation depending on the components of the metric tensor and their derivatives are found. Considerable simplifications take place if the coordinate system is orthogonal. As an example, the differential operator of the vector radiative transfer equation in both elliptical conical coordinate system and oblate spheroidal coordinate system is written down. Nonstandard parameterization of standard elliptical conical coordinate system is proposed.

  10. Coordinate metrology accuracy of systems and measurements

    CERN Document Server

    Sładek, Jerzy A

    2016-01-01

    This book focuses on effective methods for assessing the accuracy of both coordinate measuring systems and coordinate measurements. It mainly reports on original research work conducted by Sladek’s team at Cracow University of Technology’s Laboratory of Coordinate Metrology. The book describes the implementation of different methods, including artificial neural networks, the Matrix Method, the Monte Carlo method and the virtual CMM (Coordinate Measuring Machine), and demonstrates how these methods can be effectively used in practice to gauge the accuracy of coordinate measurements. Moreover, the book includes an introduction to the theory of measurement uncertainty and to key techniques for assessing measurement accuracy. All methods and tools are presented in detail, using suitable mathematical formulations and illustrated with numerous examples. The book fills an important gap in the literature, providing readers with an advanced text on a topic that has been rapidly developing in recent years. The book...

  11. Learning and coordinating in a multilayer network

    CERN Document Server

    Lugo, Haydee

    2014-01-01

    We introduce a two layer network model for social coordination incorporating two relevant ingredients: a) different networks of interaction to learn and to obtain a payoff , and b) decision making processes based both on social and strategic motivations. Two populations of agents are distributed in two layers with intralayer learning processes and playing interlayer a coordination game. We find that the skepticism about the wisdom of crowd and the local connectivity are the driving forces to accomplish full coordination of the two populations, while polarized coordinated layers are only possible for all-to-all interactions. Local interactions also allow for full coordination in the socially efficient Pareto-dominant strategy in spite of being the riskier one.

  12. Learning and coordinating in a multilayer network

    Science.gov (United States)

    Lugo, Haydée; Miguel, Maxi San

    2015-01-01

    We introduce a two layer network model for social coordination incorporating two relevant ingredients: a) different networks of interaction to learn and to obtain a pay-off, and b) decision making processes based both on social and strategic motivations. Two populations of agents are distributed in two layers with intralayer learning processes and playing interlayer a coordination game. We find that the skepticism about the wisdom of crowd and the local connectivity are the driving forces to accomplish full coordination of the two populations, while polarized coordinated layers are only possible for all-to-all interactions. Local interactions also allow for full coordination in the socially efficient Pareto-dominant strategy in spite of being the riskier one.

  13. [Fluorescence spectra of ponceau-4R].

    Science.gov (United States)

    Shi, Ai-Min; Zhu, Tuo; Gu, En-Dong; Liu, Zhou-Yi; Xu, Hui

    2009-01-01

    The fluorescence spectra of ponceau 4R induced by 220-400 nm light were studied in the present paper. The result shows that ponceau 4R has four obvious fluorescence spectral peaks respectively located at 420, 530, 635 and 687 nm, each of these fluorescence spectral peaks has different best induced light, and the corresponding fluorescence spectra were listed. It was considered that this fluorescence comes from the transition n --> pi* of n electrons in the -OH and pi* --> pi of pi electrons in the naphthalene. The fluorescence spectral peaks at 420 nm come from the transition n --> pi* and the other three fluorescence spectral peaks come from pi* --> pi. But the intensity of the four fluorescence spectral peaks changes differently with the excited wavelength This paper attempted to give the expression of the four fluorescence spectral peaks based on the microcosmic mechanism. The reason for that ponceau 4R has complex fluorescence characteristic is that ponceau 4R not only has big and conjugate structure such as naphthalene and provides electron group -OH which can intensify its ability to emit fluorescence, but also absorbs electron group such as N=N which can depress its ability to emit fluorescence. Investigation on the fluorescence spectra and its characteristics will contribute to the study on the fluorescence spectra of other azo pigment and help find a new way for checking food safety.

  14. Fluorescence lifetime standards for time and frequency domain fluorescence spectroscopy

    NARCIS (Netherlands)

    Boens, N.; Qin, Wenwu; Basaric, N.; Hofkens, J.; Ameloot, M.; Pouget, J.; Lefevre, J.P.; Valeur, B.; Gratton, E.; Ven, van de M.; Silva jr., D.; Engelborghs, Y.; Willaert, K.; Sillen, A.; Rumbles, G.; Philips, D.; Visser, A.J.W.G.; Hoek, van A.; Lakowicz, J.R.; Malak, H.; Gryczynski, I.; Szabo, A.G.; Krajcarski, D.T.; Tamai, N.; Miura, A.

    2007-01-01

    A series of fluorophores with single-exponential fluorescence decays in liquid solution at 20 C were measured independently by nine laboratories using single-photon timing and multifrequency phase and modulation fluorometry instruments with lasers as excitation source. The dyes that can serve as

  15. PH-sensitive fluorescence detection by diffuse fluorescence tomography

    Science.gov (United States)

    Li, Jiao; Gao, Feng; Duan, Linjing; Wang, Xin; Zhang, Limin; Zhao, Huijuan

    2012-03-01

    The importance of cellular pH has been shown clearly in the study of cell activity, pathological feature, drug metabolism, etc. Monitoring pH changes of living cells and imaging the regions with abnormal pH values in vivo could provide the physiologic and pathologic information for the research of the cell biology, pharmacokinetics, diagnostics and therapeutics of certain diseases such as cancer. Thus, pH-sensitive fluorescence imaging of bulk tissues has been attracting great attention in the regime of near-infrared diffuse fluorescence tomography (DFT), an efficient small-animal imaging tool. In this paper, the feasibility of quantifying pH-sensitive fluorescence targets in turbid medium is investigated using both time-domain and steady-state DFT methods. By use of the specifically designed time-domain and continuous-wave systems and the previously proposed image reconstruction scheme, we validate the method through 2-dimensional imaging experiments on a small-animal-sized phantom with multiply targets of distinct pH values. The results show that the approach can localize the targets with reasonable accuracy and achieve quantitative reconstruction of the pH-sensitive fluorescent yield.

  16. Use of fluorescent Ca2+ dyes with green fluorescent protein and its variants: problems and solutions.

    OpenAIRE

    Bolsover, S.; O. Ibrahim; O'luanaigh, N; Williams, H; Cockcroft, S

    2001-01-01

    We have studied the degree to which fluorescent Ca(2+) indicator dyes, and green fluorescent protein and its variants, can be used together. We find that the most commonly used fluorescent protein, enhanced green fluorescent protein (EGFP), seriously contaminates fura 2 signals. We suggest two alternative combinations for which there is no detectable contamination of the Ca(2+) indicator signal by the fluorescent protein. Blue fluorescent protein can be used with the Ca(2+) indicator Fura Red...

  17. Hierarchical self-assembly of a fluorescence emission-enhanced organogelator and its multiple stimuli-responsive behaviors.

    Science.gov (United States)

    Ren, Yuan-Yuan; Xu, Zheng; Li, Guoqiang; Huang, Junhai; Fan, Xiaotian; Xu, Lin

    2017-01-03

    A discrete hexagonal metallacycle 1 decorated with tetraphenylethylene, amide groups and long hydrophobic alkyl chains was constructed via [3 + 3] coordination-driven self-assembly, from which the fluorescence emission-enhanced organogelator with multiple stimuli-responsiveness was successfully prepared via hierarchical self-assembly.

  18. Chemometric endogenous fluorescence for tissue diagnosis

    Science.gov (United States)

    Li, Run; Vasquez, Kevin; Xu, M.

    2017-02-01

    Endogenous fluorescence is a powerful technique for probing both structure and function of tissue. We show that enabling wide-field fluorescence microscopy with chemometrics can significantly enhance the performance of tissue diagnosis with endogenous fluorescence. The spatial distribution and absolute concentration of fluorophores is uncovered with non-negative factorization aided by the spatial diversity from microscopic autofluorescence color images. Fluorescence quantification in terms of its absolute concentration map avoids issues dependent on specific measurement approach or systems and yields biologically meaningful data. The standardization of endogenous fluorescence in terms of absolute concentration will facilitate its translation to the clinics and simplifies the assessment of competing methods relating to tissue fluorescence.

  19. Sensory Motor Coordination in Robonaut

    Science.gov (United States)

    Peters, Richard Alan, II

    2003-01-01

    As a participant of the year 2000 NASA Summer Faculty Fellowship Program, I worked with the engineers of the Dexterous Robotics Laboratory at NASA Johnson Space Center on the Robonaut project. The Robonaut is an articulated torso with two dexterous arms, left and right five-fingered hands, and a head with cameras mounted on an articulated neck. This advanced space robot, now driven only teleoperatively using VR gloves, sensors and helmets, is to be upgraded to a thinking system that can find, interact with and assist humans autonomously, allowing the Crew to work with Robonaut as a (junior) member of their team. Thus, the work performed this summer was toward the goal of enabling Robonaut to operate autonomously as an intelligent assistant to astronauts. Our underlying hypothesis is that a robot can develop intelligence if it learns a set of basic behaviors (i.e., reflexes - actions tightly coupled to sensing) and through experience learns how to sequence these to solve problems or to accomplish higher-level tasks. We describe our approach to the automatic acquisition of basic behaviors as learning sensory-motor coordination (SMC). Although research in the ontogenesis of animals development from the time of conception) supports the approach of learning SMC as the foundation for intelligent, autonomous behavior, we do not know whether it will prove viable for the development of autonomy in robots. The first step in testing the hypothesis is to determine if SMC can be learned by the robot. To do this, we have taken advantage of Robonaut's teleoperated control system. When a person teleoperates Robonaut, the person's own SMC causes the robot to act purposefully. If the sensory signals that the robot detects during teleoperation are recorded over several repetitions of the same task, it should be possible through signal analysis to identify the sensory-motor couplings that accompany purposeful motion. In this report, reasons for suspecting SMC as the basis for

  20. A Dimmable Electrodeless Fluorescent Lamp

    Science.gov (United States)

    Chen, Yuming; Long, Qi; Chen, Dahua; Li, Weide; Wang, Aiqun

    A dimmable electrodeless fluorescent lamp (induction lamp) is introduced in this paper. The principles of the induction lamp are introduced in details. A dimming approach for the lamp is discussed in both theory and experiment. A continuous dimming range from 30%-100% can be realized with the application of the IC chip.

  1. Fluorescence Spectroscopy in a Shoebox

    Science.gov (United States)

    Farooq Wahab, M.

    2007-08-01

    This article describes construction of a simple, inexpensive fluorometer. It utilizes a flashlight or sunlight source, highlighter marker ink, bowl of water with mirror as dispersing element, and colored cellophane sheets as filters. The human eye is used as a detector. This apparatus is used to demonstrate important concepts related to fluorescence spectroscopy. Using ink from a highlighter marker, one can demonstrate the difference between light scattering and fluorescence emission, the need for an intense light source, phenomenon of the Stokes shift, the choice of filters, the preferred geometry of excitation source and emission detector, and the low detection limits that can be achieved by fluorescence measurements. By reflecting the fluorescence emission from a compact disk, it can be seen that the light emitted by molecules is not monochromatic. Furthermore, a spectrofluorometer is constructed using gratings made from a DVD or a CD. The shoebox fluorometer and spectrofluorometer can serve as useful teaching aids in places where commercial instruments are not available, and it avoids the black box problem of modern instruments.

  2. Fluorescence Spectroscopy and its Applications

    Indian Academy of Sciences (India)

    TECS

    ferent aspects of fluorescence spectroscopy and applications in chemistry, which I hope would be useful to both chemists and spectroscopists. I thank the Indian Academy of Sciences and, in particular, the Editorial. Board of the Journal of Chemical Sciences for inviting me to be the Guest. Editor of this Special Issue.

  3. Fluorescence for high school students

    NARCIS (Netherlands)

    Schultheiss, N.G.; Kool, T.W.

    2012-01-01

    In a not obligatory series of lessons for high school students in the Netherlands we discuss the fluorescence aspects of anthracene. These lessons were developed because HiSPARC (High school Project on Astrophysics Research with Cosmics) detection of cosmic rays are available for different secondary

  4. Fluorescence diagnostics in oncological gynecology

    Science.gov (United States)

    Belyaeva, Ludmila A.; Adamyan, Leila V.; Kozachenko, Vladimir P.; Stratonnikov, Alexander A.; Stranadko, Eugene F.; Loschenov, Victor B.

    2003-10-01

    The method of fluorescent diagnostics (FD) of tumors is a promising tool that may allow to increase sensitivity of tumor detection especially at initial stages. One of the most promising photosensitizers today is 5-aminolevulinic acid (5-ALA) that, actually, is not photosensitizer itself but precursor of protoporphyrin IX (PpIX). This paper deals with cancer diagnostics in gynecology by means of ALA-induced Pp IX laser-fluorescence spectroscopy. The tissue fluorescence spectra in vivo were studied in patients with various pathologies of ovaries, uterine and vulva after 5-aminolevulinic acid administration. It was shown that different pathologies varies in accumulation of Pp IX. Coefficient of fluorescence kf for normal tissue is not high, but exceptions are endometrium and mucous membrane of uterine tubes. Benign tumors of uterus and ovary have low values of kf, but polyps of endometrium exhibit high kf. Optical express-biopsy is important for diagnosis of ovarian cancer and micrometastatic spread. Coefficients of diagnostic contrast were determined for cancer of endometrium, cervical cancer, vulvar cancer.

  5. Ultrasensitive and highly selective detection of Cu2 + ions based on a new carbazole-Schiff

    Science.gov (United States)

    Yin, Jun; Bing, Qijing; Wang, Lin; Wang, Guang

    2018-01-01

    A new chemosensor for Cu2 + based on Schiff base with high sensitivity and selectivity was designed and synthesized. The fluorescence intensity of the chemosensor in CH3CN solution was enhanced 160-fold after the addition of 10 equiv. Cu2 + over other metal ions. In addition, it also facilitates colorimetric detection for Cu2 + in CH3CN solution. The chemosensor displayed low detection limit and fast response time to Cu2 +.

  6. Fluorescent deep-blue and hybrid white emitting devices based on a naphthalene-benzofuran compound

    KAUST Repository

    Yang, Xiaohui

    2013-08-01

    We report the synthesis, photophysics and electrochemical properties of naphthalene-benzofuran compound 1 and its application in organic light emitting devices. Fluorescent deep-blue emitting devices employing 1 as the emitting dopant embedded in 4-4′-bis(9-carbazolyl)-2,2′-biphenyl (CBP) host show the peak external quantum efficiency of 4.5% and Commission Internationale d\\'Énclairage (CIE) coordinates of (0.15, 0.07). Hybrid white devices using fluorescent blue emitting layer with 1 and a phosphorescent orange emitting layer based on an iridium-complex show the peak external quantum efficiency above 10% and CIE coordinates of (0.31, 0.37). © 2013 Published by Elsevier B.V.

  7. Movement constraints on interpersonal coordination and communication.

    Science.gov (United States)

    Tolston, Michael T; Shockley, Kevin; Riley, Michael A; Richardson, Michael J

    2014-10-01

    The present study investigated how constraining movement affects interpersonal coordination and joint cognitive performance. Pairs of participants worked cooperatively to solve picture-puzzle tasks in which they conversed to identify differences between pictures in 3 degree-of-constraint conditions: both participants were free to move their hands (free-free; FF); both participants' hands were restrained (restrained-restrained; RR); and the hands of 1 participant were free while the hands of the other participant were restrained (free-restrained; FR). Eye tracking data were collected, and movement was measured at the waist, hand, and head. Data were analyzed using Cross-Recurrence Quantification Analysis (CRQ). Postural sway coordination, gaze coordination, and task performance were predicted to be highest in FF, followed by RR, and then by FR. Results showed the asymmetric FR condition generally exhibited lesser degrees of coordination than the symmetric Conditions FF and RR, and that the patterning of coordination in the symmetric conditions varied across the measured body segments. These results demonstrate that movement restraints affect not only interpersonal postural coordination, but also joint attention. Additionally, significant positive relationships were found between task performance and total amount of anterior-posterior movement measured at the head, hand and waist; number of utterances; and number of differences pairs found in the puzzles. These findings indicate a relationship between movement and task performance consistent with the hypotheses that both interpersonal coordination and cognitive performance are sensitive to local action constraints.

  8. Ultraviolet Fluorescence Spectra of Fingerprints

    Directory of Open Access Journals (Sweden)

    Naoki Saitoh

    2005-01-01

    Full Text Available We have studied inherent fluorescence spectra and imaging of fingerprints in the deep ultraviolet (UV region with a nanosecond-pulsed Nd-YAG laser system that consists of a tunable laser, a cooled CCD camera, and a grating spectrometer. In this paper, we have studied UV fluorescence spectra of fingerprints under 266-nm illumination. Fluorescence spectra of fingerprints have two main peaks, around 330 nm (peak A and 440 nm (peak B. At first, when a fingerprint has just been pressed, peak A is dominant. However, its intensity reduces as the total illumination time increases. On the other hand, peak B is weak at first. It appears after enough 266-nm illumination and its intensity increases as time elapses. After 3 h of illumination, peak A almost diminishes and peak B becomes dominant. By leaving the fingerprint under a fluorescent lamp in a room without laser illumination, peak A can be restored partly, while the intensity of peak B still increases.Time-resolved fluorescence spectra were also measured for these two peaks. The lifetime of each peak is 2.0 nsec (peak A and 6.2 nsec (peak B on average. Both peaks seem to consist of several components with different lifetimes. In the case of peak A, the 330-nm peak decays fast and a new component at 360 nm becomes dominant when the delay time exceeds 20 nsec. In the case of peak B, unlike peak A, no clear peak separation is observed, but the peak position seems to move from 440 to 460 nm when the delay time becomes larger.

  9. Peptide tag/probe pairs based on the coordination chemistry for protein labeling.

    Science.gov (United States)

    Uchinomiya, Shohei; Ojida, Akio; Hamachi, Itaru

    2014-02-17

    Protein-labeling methods serve as essential tools for analyzing functions of proteins of interest under complicated biological conditions such as in live cells. These labeling methods are useful not only to fluorescently visualize proteins of interest in biological systems but also to conduct protein and cell analyses by harnessing the unique functions of molecular probes. Among the various labeling methods available, an appropriate binding pair consisting of a short peptide and a de novo designed small molecular probe has attracted attention because of its wide utility and versatility. Interestingly, most peptide tag/probe pairs exploit metal-ligand coordination interactions as the main binding force responsible for their association. Herein, we provide an overview of the recent progress of these coordination-chemistry-based protein-labeling methods and their applications for fluorescence imaging and functional analysis of cellular proteins, while highlighting our originally developed labeling methods. These successful examples clearly exemplify the utility and versatility of metal coordination chemistry in protein functional analysis.

  10. Polysulfide Coordination Clusters of the Lanthanides.

    Science.gov (United States)

    Ma, Ying-Zhao; Bestgen, Sebastian; Gamer, Michael T; Konchenko, Sergey N; Roesky, Peter W

    2017-10-16

    The reaction of [(DippForm)2 Ln(thf)2 ] with an excess of elemental sulfur in toluene resulted in the formation of the trinuclear polysulfide coordination clusters [(DippForm)3 Ln3 S12 ] (Ln=Sm, Yb; DippForm=N,N'-bis(2,6-diisopropylphenyl)formamidinate). These are the first f element coordination clusters (Lnn Sx ) with a larger polysulfide unit (n and x>2). The formation of the coordination clusters can be rationalized by the reductive cleavage of S8 with divalent lanthanides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. An Enhanced Model for Stochastic Coordination

    Directory of Open Access Journals (Sweden)

    Nuno Oliveira

    2016-10-01

    Full Text Available Applications developed over the cloud coordinate several, often anonymous, computational resources, distributed over different execution nodes, within flexible architectures. Coordination models able to represent quantitative data provide a powerful basis for their analysis and validation. This paper extends IMCreo, a semantic model for Stochastic reo based on interactive Markov chains, to enhance its scalability, by regarding each channel and node, as well as interface components, as independent stochastic processes that may (or may not synchronise with the rest of the coordination circuit.

  12. Pollution detection using the spectral fluorescent signatures (SFS technique

    Directory of Open Access Journals (Sweden)

    Mª Del Carmen Martín

    2014-06-01

    provide quantitative measurement through the use of algorithms based on libraries from previous samples. Since the different materials and compounds have different spectral signatures of fluorescence, it is possible with a single measure to analyze the different components in the sample. The reliability of this method will depend on the library of samples used. Several substances have been studied through their fluorescence response to incident light by using different methods. Firstly, different oil products have been analyzed in the laboratory, by using eight LED light sources with wavelengths ranging from 270 to 850 nm to excite the samples (Figure 1, employing a USB4000-FL Fluorescence Spectrometer to register the fluorescence spectra. On the one hand the SFS of twelve different types of oils has been obtained by exciting the samples with a 310nm LED light source (in absence of any other source of light (Figure 2. Each sample consisted of 5 ml of distilled water and 400 μl of oil. On the other hand the SFS of oil, gasoline, engine oil and heavy oil has been acquired using all LEDs (Figure 3. Secondly, the Instant Screener M53UVC SFS analyzer has been used to obtain the SFS for screening detection of aluminium concentrations in water samples by a derivatization method. The Instant Screener (IS presents two different software versions (UV and BIO, associated with the excitation and emission wavelength provided and registered (respectively by the instrument. In UV software version, excitation wavelength ranges from 240 to 360 nm and fluorescence is registered from 260 to 575 nm whereas in the BIO version excitation wavelength varies from 400 to 650 nm while emission is registered from 530 to 730 nm. The study is concentrated on the development of a sensitive and selective methodology for the non-fluorescent aluminium ion detection based on the analytical derivatization reaction strategy to form a characteristic fluorescent coordination complex [1, 2]. Morin (Flavonol

  13. Fluorescent Protein Approaches in Alpha Herpesvirus Research

    Directory of Open Access Journals (Sweden)

    Ian B. Hogue

    2015-11-01

    Full Text Available In the nearly two decades since the popularization of green fluorescent protein (GFP, fluorescent protein-based methodologies have revolutionized molecular and cell biology, allowing us to literally see biological processes as never before. Naturally, this revolution has extended to virology in general, and to the study of alpha herpesviruses in particular. In this review, we provide a compendium of reported fluorescent protein fusions to herpes simplex virus 1 (HSV-1 and pseudorabies virus (PRV structural proteins, discuss the underappreciated challenges of fluorescent protein-based approaches in the context of a replicating virus, and describe general strategies and best practices for creating new fluorescent fusions. We compare fluorescent protein methods to alternative approaches, and review two instructive examples of the caveats associated with fluorescent protein fusions, including describing several improved fluorescent capsid fusions in PRV. Finally, we present our future perspectives on the types of powerful experiments these tools now offer.

  14. Fluorescent Protein Approaches in Alpha Herpesvirus Research

    Science.gov (United States)

    Hogue, Ian B.; Bosse, Jens B.; Engel, Esteban A.; Scherer, Julian; Hu, Jiun-Ruey; del Rio, Tony; Enquist, Lynn W.

    2015-01-01

    In the nearly two decades since the popularization of green fluorescent protein (GFP), fluorescent protein-based methodologies have revolutionized molecular and cell biology, allowing us to literally see biological processes as never before. Naturally, this revolution has extended to virology in general, and to the study of alpha herpesviruses in particular. In this review, we provide a compendium of reported fluorescent protein fusions to herpes simplex virus 1 (HSV-1) and pseudorabies virus (PRV) structural proteins, discuss the underappreciated challenges of fluorescent protein-based approaches in the context of a replicating virus, and describe general strategies and best practices for creating new fluorescent fusions. We compare fluorescent protein methods to alternative approaches, and review two instructive examples of the caveats associated with fluorescent protein fusions, including describing several improved fluorescent capsid fusions in PRV. Finally, we present our future perspectives on the types of powerful experiments these tools now offer. PMID:26610544

  15. Preparation and Application of Fluorescent Carbon Dots

    National Research Council Canada - National Science Library

    Zuo, Jun; Jiang, Tao; Zhao, Xiaojing; Xiong, Xiaohong; Xiao, Saijin; Zhu, Zhiqiang

    2015-01-01

      Fluorescent carbon dots (CDs) are a novel type of fluorescent nanomaterials, which not only possess the specific quantum confinement effects of nanomaterials due to the small size of nanomaterials, but also have good...

  16. Preparation and Application of Fluorescent Carbon Dots

    Directory of Open Access Journals (Sweden)

    Jun Zuo

    2015-01-01

    Full Text Available Fluorescent carbon dots (CDs are a novel type of fluorescent nanomaterials, which not only possess the specific quantum confinement effects of nanomaterials due to the small size of nanomaterials, but also have good biocompatibility and high fluorescence. Meanwhile, fluorescence CDs overcome the shortcomings of high toxicity of traditional nanomaterials. Moreover, the preparation procedure of fluorescent CDs is simple and easy. Therefore, fluorescent CDs have great potential applied in photocatalysis, biochemical sensing, bioimaging, drug delivery, and other related areas. In this paper, recent hot researches on fluorescent CDs are reviewed and some problems in the progress of fluorescent CDs are also summarized. At last, a future outlook in this direction is presented.

  17. In vivo near-infrared fluorescence three-dimensional positioning system with binocular stereovision.

    Science.gov (United States)

    Song, Bofan; Jin, Wei; Wang, Ying; Jin, Qinhan; Mu, Ying

    2014-01-01

    Fluorescence is a powerful tool for in-vivo imaging in living animals. The traditional in-vivo fluorescence imaging equipment is based on single-view two-dimensional imaging systems. However, they cannot meet the needs for accurate positioning during modern scientific research. A near-infrared in-vivo fluorescence imaging system is demonstrated, which has the capability of deep source signal detecting and three-dimensional positioning. A three-dimensional coordinates computing (TDCP) method including a preprocess algorithm is presented based on binocular stereo vision theory, to figure out the solution for diffusive nature of light in tissue and the emission spectra overlap of fluorescent labels. This algorithm is validated to be efficient to extract targets from multispectral images and determine the spot center of biological interests. Further data analysis indicates that this TDCP method could be used in three-dimensional positioning of the fluorescent target in small animals. The study also suggests that the combination of a large power laser and deep cooling charge-coupled device will provide an attractive approach for fluorescent detection from deep sources. This work demonstrates the potential of binocular stereo vision theory for three-dimensional positioning for living animal in-vivo imaging.

  18. Interactions of hemin with bovine serum albumin and human hemoglobin: A fluorescence quenching study.

    Science.gov (United States)

    Makarska-Bialokoz, Magdalena

    2017-12-01

    The binding interactions between hemin (Hmi) and bovine serum albumin (BSA) or human hemoglobin (HHb), respectively, have been examined in aqueous solution at pH=7.4, applying UV-vis absorption, as well as steady-state, synchronous and three-dimensional fluorescence spectra techniques. Representative results received for both BSA and HHb intrinsic fluorescence proceeding from the interactions with hemin suggest the formation of stacking non-covalent and non-fluorescent complexes in both the Hmi-BSA and Hmi-HHb systems, with highly possible concurrent formation of a coordinate bond between a group on the protein surface and the metal in Hmi molecule. All the values of calculated parameters, the binding, fluorescence quenching and bimolecular quenching rate constants point to the involvement of static quenching in both the systems studied. The blue shift in the synchronous fluorescence spectra imply the participation of both tryptophan and tyrosine residues in quenching of BSA and HHb intrinsic fluorescence. Depicted outcomes suggest that hemin is supposedly able to influence the physiological functions of BSA and HHb, the most important blood proteins, particularly in case of its overuse. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Highly Fluorescent Metal-Organic-Framework Nanocomposites for Photonic Applications.

    Science.gov (United States)

    Monguzzi, A; Ballabio, M; Yanai, N; Kimizuka, N; Fazzi, D; Campione, M; Meinardi, F

    2018-01-10

    Metal-organic frameworks (MOFs) are porous hybrid materials built up from organic ligands coordinated to metal ions or clusters by means of self-assembly strategies. The peculiarity of these materials is the possibility, according to specific synthetic routes, to manipulate both the composition and ligands arrangement in order to control their optical and energy-transport properties. Therefore, optimized MOFs nanocrystals (nano-MOFs) can potentially represent the next generation of luminescent materials with features similar to those of their inorganic predecessors, that is, the colloidal semiconductor quantum dots. The luminescence of fluorescent nano-MOFs is generated through the radiative recombination of ligand molecular excitons. The uniqueness of these nanocrystals is the possibility to pack the ligand chromophores close enough to allow a fast exciton diffusion but sufficiently far from each other preventing the aggregation-induced effects of the organic crystals. In particular, the formation of strongly coupled dimers or excimers is avoided, thus preserving the optical features of the isolated molecule. However, nano-MOFs have a very small fluorescence quantum yield (QY). In order to overcome this limitation and achieve highly emitting systems, we analyzed the fluorescence process in blue emitting nano-MOFs and modeled the diffusion and quenching mechanism of photogenerated singlet excitons. Our results demonstrate that the excitons quenching in nano-MOFs is mainly due to the presence of surface-located, nonradiative recombination centers. In analogy with their inorganic counterparts, we found that the passivation of the nano-MOF surfaces is a straightforward method to enhance the emission efficiency. By embedding the nanocrystals in an inert polymeric host, we observed a +200% increment of the fluorescence QY, thus recovering the emission properties of the isolated ligand in solution.

  20. Electromagnetic fields emitted by fluorescent and compact fluorescent lamps

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, C.; Sebastiao, D.; Ladeira, D.; Carpinteiro, G.; Antunes, M.; Correia, L.M.; Fernandes, C. [Instituto de Telecomunicacoes, Instituto Superior Tecnico, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal)

    2009-05-15

    In the scope of the monIT Project, it was found that fluorescent and compact fluorescent lamps are also important sources of radiation. More than increasing electromagnetic field (EMF) levels in a particular environment, the radiated EMFs from ballasts may cause interference in other devices. Two different lamps are analysed, both in terms of their radiated frequency spectrum and of their compliance with European EMF recommended exposure levels. As expected, the analysis of results shows that, in the immediate vicinity of a lamp, EMF levels radiated by lighting devices depend on the lamp power. Finally, one can conclude that EMFs radiated from both lamps are in compliance with the EMF reference levels. (author)

  1. Two-photon excited hemoglobin fluorescence

    OpenAIRE

    Zheng, Wei; Li, Dong; Zeng, Yan; Luo, Yi; Qu, Jianan Y.

    2010-01-01

    We discovered that hemoglobin emits high energy Soret fluorescence when two-photon excited by the visible femtosecond light sources. The unique spectral and temporal characteristics of hemoglobin fluorescence were measured by using a time-resolved spectroscopic detection system. The high energy Soret fluorescence of hemoglobin shows the spectral peak at 438 nm with extremely short lifetime. This discovery enables two-photon excitation fluorescence microscopy to become a potentially powerful t...

  2. Entangled-photon coincidence fluorescence imaging.

    Science.gov (United States)

    Scarcelli, Giuliano; Yun, Seok H

    2008-09-29

    We describe fluorescence imaging using the second-order correlation of entangled photon pairs. The proposed method is based on the principle that one photon of the pair carries information on where the other photon has been absorbed and has produced fluorescence in a sample. Because fluorescent molecules serve as "detectors" breaking the entanglement, multiply-scattered fluorescence photons within the sample do not cause image blur. We discuss experimental implementations.

  3. HYbrid Coordinate Ocean Model (HYCOM): Global

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Global HYbrid Coordinate Ocean Model (HYCOM) and U.S. Navy Coupled Ocean Data Assimilation (NCODA) 3-day, daily forecast at approximately 9-km (1/12-degree)...

  4. Interpersonal Coordination: Methods, Achievements, and Challenges

    Directory of Open Access Journals (Sweden)

    Carlos Cornejo

    2017-09-01

    Full Text Available Research regarding interpersonal coordination can be traced back to the early 1960s when video recording began to be utilized in communication studies. Since then, technological advances have extended the range of techniques that can be used to accurately study interactional phenomena. Although such a diversity of methods contributes to the improvement of knowledge concerning interpersonal coordination, it has become increasingly difficult to maintain a comprehensive view of the field. In the present article, we review the main capture methods by describing their major findings, levels of description and limitations. We group them into three categories: video analysis, motion tracking, and psychophysiological and neurophysiological techniques. Revised evidence suggests that interpersonal coordination encompasses a family of morphological and temporal synchronies at different levels and that it is closely related to the construction and maintenance of a common social and affective space. We conclude by arguing that future research should address methodological challenges to advance the understanding of coordination phenomena.

  5. 47 CFR 15.525 - Coordination requirements.

    Science.gov (United States)

    2010-10-01

    ... the UWB device. If the imaging device is intended to be used for mobile applications, the geographical... coordination of routine UWB operations shall not take longer than 15 business days from the receipt of the...

  6. Anatomic breast coordinate system for mammogram analysis

    DEFF Research Database (Denmark)

    Karemore, Gopal; Brandt, S.; Karssemeijer, N.

    2011-01-01

    methodologies as seen from table 2 in given temporal study. Conclusion The curve-linear anatomical breast coordinate system facilitated computerized analysis of mammograms. The proposed coordinate system slightly improved the risk segregation by Mammographic Texture Resemblance and minimized the geometrical......Purpose Many researchers have investigated measures also other than density in the mammogram such as measures based on texture to improve breast cancer risk assessment. However, parenchymal texture characteristics are highly dependent on the orientation of vasculature structure and fibrous tissue...... inside the breast. Most of the risk assessment and CAD modules use a breast region in a image centered Cartesian x,y coordinate system. Nevertheless, anatomical structure follows curve-linear trajectories. We examined an anatomical breast coordinate system that preserves the anatomical correspondence...

  7. Modeling, Control and Coordination of Helicopter Systems

    CERN Document Server

    Ren, Beibei; Chen, Chang; Fua, Cheng-Heng; Lee, Tong Heng

    2012-01-01

    Modeling, Control and Coordination of Helicopter Systems provides a comprehensive treatment of helicopter systems, ranging from related nonlinear flight dynamic modeling and stability analysis to advanced control design for single helicopter systems, and also covers issues related to the coordination and formation control of multiple helicopter systems to achieve high performance tasks. Ensuring stability in helicopter flight is a challenging problem for nonlinear control design and development. This book is a valuable reference on modeling, control and coordination of helicopter systems,providing readers with practical solutions for the problems that still plague helicopter system design and implementation. Readers will gain a complete picture of helicopters at the systems level, as well as a better understanding of the technical intricacies involved. This book also: Presents a complete picture of modeling, control and coordination for helicopter systems Provides a modeling platform for a general class of ro...

  8. Users manual for coordinate generation code CRDSRA

    Science.gov (United States)

    Shamroth, S. J.

    1985-01-01

    Generation of a viable coordinate system represents an important component of an isolated airfoil Navier-Stokes calculation. The manual describes a computer code for generation of such a coordinate system. The coordinate system is a general nonorthogonal one in which high resolution normal to the airfoil is obtained in the vicinity of the airfoil surface, and high resolution along the airfoil surface is obtained in the vicinity of the airfoil leading edge. The method of generation is a constructive technique which leads to a C type coordinate grid. The method of construction as well as input and output definitions are contained herein. The computer code itself as well as a sample output is being submitted to COSMIC.

  9. Coordination Approaches for Complex Software Systems

    NARCIS (Netherlands)

    Bosse, T.; Hoogendoorn, M.; Treur, J.

    2006-01-01

    This document presents the results of a collaboration between the Vrije Universiteit Amsterdam, Department of Artificial Intelligence and Force Vision to investigate coordination approaches for complex software systems. The project was funded by Force Vision.

  10. Coordinated Specialty Care Fact Sheet and Checklist

    Science.gov (United States)

    ... Checklist Share Coordinated Specialty Care Fact Sheet and Checklist Download PDF Download ePub Order a free hardcopy ... webpage: http://www.nimh.nih.gov/raise . CSC Checklist If you are interested in a CSC program, ...

  11. Value-Oriented Coordination Process Modeling

    NARCIS (Netherlands)

    Fatemi, Hassan; van Sinderen, Marten J.; Wieringa, Roelf J.; Hull, Richard; Mendling, Jan; Tai, Stefan

    Business webs are collections of enterprises designed to jointly satisfy a consumer need. Designing business webs calls for modeling the collaboration of enterprises from different perspectives, in particular the business value and coordination process perspectives, and for mutually aligning these

  12. Neural correlates of developmental coordination disorder

    NARCIS (Netherlands)

    Peters, Lieke H. J.; Maathuis, Carel G. B.; Hadders-Algra, Mijna

    2013-01-01

    AIM To review neuroimaging studies in children with developmental coordination disorder (DCD) systematically. Because only a few studies addressed this, we broadened our search and included neuroimaging studies in children with perinatal adversities and motor impairment without cerebral palsy.

  13. Modeling Students' Units Coordinating Activity

    Science.gov (United States)

    Boyce, Steven James

    2014-01-01

    Primarily via constructivist teaching experiment methodology, "units coordination" (Steffe, 1992) has emerged as a useful construct for modeling students' psychological constructions pertaining to several mathematical domains, including counting sequences, whole number multiplicative conceptions, and fractions schemes. I describe how…

  14. 42 CFR 38.1 - Purpose; coordination.

    Science.gov (United States)

    2010-10-01

    ... DISASTER ASSISTANCE FOR CRISIS COUNSELING AND TRAINING § 38.1 Purpose; coordination. (a) Purpose. This part... Federal Disaster Assistance Administration. Contracts and grants awarded under this part are subject to...

  15. Bilateral Coordination of Children who are Blind.

    Science.gov (United States)

    Rutkowska, Izabela; Lieberman, Lauren J; Bednarczuk, Grzegorz; Molik, Bartosz; Kazimierska-Kowalewska, Kalina; Marszałek, Jolanta; Gómez-Ruano, Miguel-Ángel

    2016-04-01

    The purpose of this study was to evaluate the bilateral coordination in children and adolescents with visual impairments aged 7 to 18 years in comparison to their sighted peers. An additional objective was to identify the influence of sex and age on bilateral coordination. Seventy-five individuals with congenital severe visual impairment (40 girls and 35 boys) comprised the visually impaired group. The Sighted group comprised 139 youth without visual impairment. Subtest 4 of the Bruininks-Oseretsky Test of Motor Proficiency was administered to test bilateral coordination. To analyze the effect of the independent variables in the results obtained in the Subtest 4, four linear regression models were applied according to group and sex. The results indicated that severe visual impairment and lack of visual sensation had a negative effect on the development of participants' bilateral coordination, which however did not depend on sex or age. © The Author(s) 2016.

  16. Towards reduction of Paradigm coordination models

    NARCIS (Netherlands)

    S. Andova; L.P.J. Groenewegen; E.P. de Vink (Erik Peter); L. Aceto (Luca); M.R. Mousavi

    2011-01-01

    htmlabstractThe coordination modelling language Paradigm addresses collaboration between components in terms of dynamic constraints. Within a Paradigm model, component dynamics are consistently specified at a detailed and a global level of abstraction. To enable automated verification of Paradigm

  17. Coordinating knowledge transfer within manufacturing networks

    DEFF Research Database (Denmark)

    Yang, Cheng; Johansen, John; Boer, Harry

    2008-01-01

    Along with increasing globalization, the management of international manufacturing networks is becoming increasingly important for industrial companies. This paper mainly focuses on the coordination of knowledge transfer within manufacturing networks. In this context, we propose the time-place ma...

  18. Interpersonal Coordination: Methods, Achievements, and Challenges

    Science.gov (United States)

    Cornejo, Carlos; Cuadros, Zamara; Morales, Ricardo; Paredes, Javiera

    2017-01-01

    Research regarding interpersonal coordination can be traced back to the early 1960s when video recording began to be utilized in communication studies. Since then, technological advances have extended the range of techniques that can be used to accurately study interactional phenomena. Although such a diversity of methods contributes to the improvement of knowledge concerning interpersonal coordination, it has become increasingly difficult to maintain a comprehensive view of the field. In the present article, we review the main capture methods by describing their major findings, levels of description and limitations. We group them into three categories: video analysis, motion tracking, and psychophysiological and neurophysiological techniques. Revised evidence suggests that interpersonal coordination encompasses a family of morphological and temporal synchronies at different levels and that it is closely related to the construction and maintenance of a common social and affective space. We conclude by arguing that future research should address methodological challenges to advance the understanding of coordination phenomena. PMID:29021769

  19. Selective Placement Program Coordinator (SPPC) Directory

    Data.gov (United States)

    Office of Personnel Management — List of the Selective Placement Program Coordinators (SPPC) in Federal agencies, updated as needed. Users can filter the list by choosing a state and/or agency name.

  20. Demonstrating Fluorescence with Neon Paper and Plastic

    Science.gov (United States)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  1. Binocular coordination in response to stereoscopic stimuli.

    OpenAIRE

    Liversedge, S.P.; Holliman, N. S.; Blythe, H.I.

    2009-01-01

    Humans actively explore their visual environment by moving their eyes. Precise coordination of the eyes during visual scanning underlies the experience of a unified perceptual representation and is important for the perception of depth. We report data from three psychological experiments investigating human binocular coordination during visual processing of stereoscopic stimuli.In the first experiment participants were required to read sentences that contained a stereoscopically presented tar...

  2. The Lanthanide Contraction beyond Coordination Chemistry.

    Science.gov (United States)

    Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K; Olvera de la Cruz, Monica; Qiao, Baofu; Ellis, Ross J

    2016-05-10

    The lanthanide contraction is conceptualized traditionally through coordination chemistry. Here we break this mold in a structural study of lanthanide ions dissolved in an amphiphilic liquid. The lanthanide contraction perturbs the weak interactions between molecular aggregates that drive mesoscale assembly and emergent behavior. The weak interactions correlate with lanthanide ion transport properties, suggesting new strategies for rare-earth separation that exploit forces outside of the coordination sphere. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Marching Cubes in Cylindrical and Spherical Coordinates

    Science.gov (United States)

    Goldsmith, J.; Jacobson, A. S.

    1996-01-01

    Isosurface extraction is a common analysis and visualization technique for three-dimensional scalar data. Marching Cubes is the most commonly-used algorithm for finding polygonal representations of isosurfaces in such data. We extend Marching Cubes to produce geometry for data sets that lie in spherical and cylindrical coordinate systems as well as show the steps for derivation of transformations for other coordinate systems.

  4. Chain coordinators’ strategic leadership and coordination effectiveness

    OpenAIRE

    Akhtar, Pervaiz; Kaur, Sushil; Punjaisri, Khanyapuss

    2017-01-01

    Purpose\\ud Although suitable leadership is crucial for chain coordinators (chief executive officers (CEOs), managing directors and heads of departments) to achieve the effectiveness of supply chain coordination (operational and social performances contributing to financial performance), the potential caveats in New Zealand-Euro agri-food supply chains are the lack of theoretical as well as empirical investigations that scrutinize the linkages between leadership styles, their interactions and ...

  5. Total Internal Reflection Fluorescence Microscopy Imaging-Guided Confocal Single-Molecule Fluorescence Spectroscopy

    OpenAIRE

    Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter

    2013-01-01

    We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...

  6. ATP Changes the Fluorescence Lifetime of Cyan Fluorescent protein via an Interaction with His148

    NARCIS (Netherlands)

    Borst, J.W.; Willemse, M.; Slijkhuis, R.; Krogt, G.; Laptenok, S.; Jalink, K.; Wieringa, B.; Fransen, J.A.M.

    2010-01-01

    Recently, we described that ATP induces changes in YFP/CFP fluorescence intensities of Fluorescence Resonance Energy Transfer (FRET) sensors based on CFP-YFP. To get insight into this phenomenon, we employed fluorescence lifetime spectroscopy to analyze the influence of ATP on these fluorescent

  7. ATP changes the fluorescence lifetime of cyan fluorescent protein via an interaction with His148.

    NARCIS (Netherlands)

    Borst, J.W.; Willemse, M.P.; Slijkhuis, R.; Krogt, G. van der; Laptenok, S.P.; Jalink, K.; Wieringa, B.; Fransen, J.A.M.

    2010-01-01

    Recently, we described that ATP induces changes in YFP/CFP fluorescence intensities of Fluorescence Resonance Energy Transfer (FRET) sensors based on CFP-YFP. To get insight into this phenomenon, we employed fluorescence lifetime spectroscopy to analyze the influence of ATP on these fluorescent

  8. Revisiting the photophysics of 9-fluorenone: Ultrafast time-resolved fluorescence and theoretical studies

    Science.gov (United States)

    Chang, Chih-Wei; Sølling, Theis I.; Diau, Eric Wei-Guang

    2017-10-01

    Ultrafast intersystem crossing dynamics of fluorenone in gas and condensed phases were investigated by time-resolved mass spectrometry and fluorescence up-conversion spectroscopy. The former shows the ultrafast Franck-Condon relaxation and the internal conversion dynamics of isolated fluorenone in the gas phase. The latter reveals that the vibrational relaxation time is 2.2 ps and a 110 ps fluorescence lifetime of fluorenone in hexane. The fluorescence lifetime in acetonitrile and dimethylsulfoxide is 16 ns and 15.1 ns, respectively. The potential energy surface along the Cdbnd O out of plane bending motion shows that this coordinate is important for ISC in both polar and non-polar solvents.

  9. Coordinated supply chain dynamic production planning model

    Science.gov (United States)

    Chandra, Charu; Grabis, Janis

    2001-10-01

    Coordination of different and often contradicting interests of individual supply chain members is one of the important issues in supply chain management because the individual members can not succeed without success of the supply chain and vice versa. This paper investigates a supply chain dynamic production planning problem with emphasis on coordination. A planning problem is formally described using a supply chain kernel, which defines supply chain configuration, management policies, available resources and objectives both at supply chain or macro and supply chain member or micro levels. The coordinated model is solved in order to balance decisions made at the macro and micro levels and members' profitability is used as the coordination criterion. The coordinated model is used to determine inventory levels and production capacity across the supply chain. Application of the coordinated model distributes costs burden uniformly among supply chain members and preserves overall efficiency of the supply chain. Influence of the demand series uncertainty is investigated. The production planning model is a part of the integrated supply chain decision modeling system, which is shared among the supply chain members across the Internet.

  10. Sorting fluorescent nanocrystals with DNA

    Energy Technology Data Exchange (ETDEWEB)

    Gerion, Daniele; Parak, Wolfgang J.; Williams, Shara C.; Zanchet, Daniela; Micheel, Christine M.; Alivisatos, A. Paul

    2001-12-10

    Semiconductor nanocrystals with narrow and tunable fluorescence are covalently linked to oligonucleotides. These biocompounds retain the properties of both nanocrystals and DNA. Therefore, different sequences of DNA can be coded with nanocrystals and still preserve their ability to hybridize to their complements. We report the case where four different sequences of DNA are linked to four nanocrystal samples having different colors of emission in the range of 530-640 nm. When the DNA-nanocrystal conjugates are mixed together, it is possible to sort each type of nanoparticle using hybridization on a defined micrometer -size surface containing the complementary oligonucleotide. Detection of sorting requires only a single excitation source and an epifluorescence microscope. The possibility of directing fluorescent nanocrystals towards specific biological targets and detecting them, combined with their superior photo-stability compared to organic dyes, opens the way to improved biolabeling experiments, such as gene mapping on a nanometer scale or multicolor microarray analysis.

  11. Fluorescence spectroscopy for neoplasms control

    Science.gov (United States)

    Bratchenko, I. A.; Kristoforova, Yu. A.; Myakinin, O. O.; Artemyev, D. N.; Kozlov, S. V.; Moryatov, A. A.; Zakharov, V. P.

    2016-04-01

    Investigation of malignant skin tumors diagnosis was performed involving two setups for native tissues fluorescence control in visible and near infrared regions. Combined fluorescence analysis for skin malignant melanomas and basal cell carcinomas was performed. Autofluorescence spectra of normal skin and oncological pathologies stimulated by 457 nm and 785 nm lasers were registered for 74 skin tissue samples. Spectra of 10 melanomas and 27 basal cell carcinomas were registered ex vivo. Skin tumors analysis was made on the basis of autofluorescence spectra intensity and curvature for analysis of porphyrins, lipo-pigments, flavins and melanin. Separation of melanomas and basal cell carcinomas was performed on the basis of discriminant analysis. Overall accuracy of basal cell carcinomas and malignant melanomas separation in current study reached 86.5% with 70% sensitivity and 92.6% specificity.

  12. Correlative fluorescence and electron microscopy.

    Science.gov (United States)

    Schirra, Randall T; Zhang, Peijun

    2014-10-01

    Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation--integration. Copyright © 2014 John Wiley & Sons, Inc.

  13. Fluorescence imaging agents in cancerology.

    Science.gov (United States)

    Paganin-Gioanni, Aurélie; Bellard, Elisabeth; Paquereau, Laurent; Ecochard, Vincent; Golzio, Muriel; Teissié, Justin

    2010-09-01

    One of the major challenges in cancer therapy is to improve early detection and prevention using novel targeted cancer diagnostics. Detection requests specific recognition. Tumor markers have to be ideally present on the surface of cancer cells. Their targeting with ligands coupled to imaging agents make them visible/detectable. Fluorescence imaging is a newly emerging technology which is becoming a complementary medical method for cancer diagnosis. It allows detection with a high spatio-temporal resolution of tumor markers in small animals and in clinical studies. In this review, we focus on the recent outcome of basic studies in the design of new approaches (probes and devices) used to detect tumor cells by fluorescence imaging.

  14. Lanthanide-Coordinated Semiconducting Polymer Dots Used for Flow Cytometry and Mass Cytometry.

    Science.gov (United States)

    Wu, Xu; DeGottardi, Quinn; Wu, I-Che; Yu, Jiangbo; Wu, Li; Ye, Fangmao; Kuo, Chun-Ting; Kwok, William W; Chiu, Daniel T

    2017-11-20

    Simultaneous monitoring of biomarkers as well as single-cell analyses based on flow cytometry and mass cytometry are important for investigations of disease mechanisms, drug discovery, and signaling-network studies. Flow cytometry and mass cytometry are complementary to each other; however, probes that can satisfy all the requirements for these two advanced technologies are limited. In this study, we report a probe of lanthanide-coordinated semiconducting polymer dots (Pdots), which possess fluorescence and mass signals. We demonstrated the usage of this dual-functionality probe for both flow cytometry and mass cytometry in a mimetic cell mixture and human peripheral blood mononuclear cells as model systems. The probes not only offer high fluorescence signal for use in flow cytometry, but also show better performance in mass cytometry than the commercially available counterparts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 78 FR 37781 - Forest Resource Coordinating Committee; Meeting

    Science.gov (United States)

    2013-06-24

    ... Forest Service Forest Resource Coordinating Committee; Meeting AGENCY: Forest Service, USDA. ACTION: Notice of meeting; Correction. SUMMARY: The Forest Service published a document in the Federal Register... FURTHER INFORMATION CONTACT: Maya Solomon, Forest Resource Coordinating Committee Program Coordinator, 202...

  16. Chemical Principles Revisited: Some Aspects of Coordination Chemistry.

    Science.gov (United States)

    Mickey, Charles D.

    1981-01-01

    Reviews characteristics of coordination chemistry, the study of coordination compounds, a major focal point for the inorganic chemist. Provides a brief history regarding the Wernerian System and background information in modern coordination theory. (CS)

  17. Fluorescent compounds present in food

    OpenAIRE

    Soto Serrano, Axel

    2014-01-01

    Póster The food industry demands fast, reliable, cheap and reproducible methods for quality and process control. This bibliographic review work investigates florescence spectroscopy, a method that couldn’t be used in food until the recent technological advances, concretely front-face fluorescence and chemometric tools. This technology presents advantages as compared to classical methods like HPLC or capillary electrophoresis, which require qualified staff, sample preparation and are time-c...

  18. Fluorescent lamp and ballast options

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This paper reviews some of the current technologies for fluorescent lamps and ballasts with particular focus on the most common configuration in Canada - the F32T8, 4 ft length, two-lamp ballast combination. Fluorescent lamps require a high voltage surge for start-up. Technical specifications for the F32T8 lamp were provided along with reasons why they are the preferred choice. The three types of ballasts include electromagnetic, electronic and hybrid. While electromagnetic ballasts perform the same start-up duty, they are not as efficient as electronic or hybrid ballasts. Hybrid ballasts are energy efficient, but they have problems with lamp flicker, tar leakage and shorter life expectancy. Electronic ballasts eliminate flicker, do not leak and have a life expectancy of 25 years. Electronic ballasts can be instant, rapid start, or dimmable. Energy information on different types of ballast systems was presented along with a comparison of the type of light produced according to lamp and ballast combinations. This paper also presents a case study in which the lighting system of a 25-storey building was retrofitted with energy efficient fluorescent lamps and ballasts for an energy savings of about $100,000 per year and a 5 year payback period. 2 tabs., 4 figs.

  19. Fluorescent Protein Based FRET Pairs with Improved Dynamic Range for Fluorescence Lifetime Measurements

    OpenAIRE

    Bobin George Abraham; Karen S Sarkisyan; Mishin, Alexander S.; Ville Santala; Tkachenko, Nikolai V.; Matti Karp

    2015-01-01

    Fluorescence Resonance Energy Transfer (FRET) using fluorescent protein variants is widely used to study biochemical processes in living cells. FRET detection by fluorescence lifetime measurements is the most direct and robust method to measure FRET. The traditional cyan-yellow fluorescent protein based FRET pairs are getting replaced by green-red fluorescent protein variants. The green-red pair enables excitation at a longer wavelength which reduces cellular autofluorescence and phototoxicit...

  20. Fluorescent multiple chemical sensing using time-domain fluorescence lifetime imaging

    OpenAIRE

    Nagl, Stefan

    2008-01-01

    This thesis describes applications of fluorescence lifetime imaging in multiple chemical sensing approaches. Using fluorescence lifetime as an analytical parameter allows extracting more information out of probes than fluorescence intensity measurements and it is therefore attractive in order to quantitate multiple species. It leads to better data quality as fluorescence lifetime measurements are not or less affected by many sources of noise in fluorescence signals such as straylight and othe...

  1. Fluorescence lifetime imaging of skin cancer

    Science.gov (United States)

    Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

    2011-03-01

    Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

  2. Application of Fluorescent Label in Polymer Nanofibers

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka

    2017-01-01

    Full Text Available The electrospinning of fluorescent probe polyamide 6 doped by 7H-benzimidazo[2,1-a]benzo[de]isoquinolin-7-on is presented as a model processing photoluminescent nanofibers. The presence of the fluorescent probe in the fiber layers was confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR; the surface nanofiber structure was described by high-resolution fluorescence microscope and scanning electron microscope images. The prepared nanofibers with the fluorescent label were further characterized by fluorescence spectroscopy, both in the solid phase and in the solution.

  3. Fluorescence spectroscopy of synthetic melanin in solution

    Energy Technology Data Exchange (ETDEWEB)

    Perna, G.; Frassanito, M.C. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, 71100 Foggia (Italy); Palazzo, G. [Dipartimento di Chimica, Universita di Bari, Via Orabona 4, 70126 Bari (Italy); Gallone, A. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, 71100 Foggia (Italy); Mallardi, A. [ICPS-CNR, Via Orabona 4, 70126 Bari (Italy); Biagi, P.F. [Dipartimento Interateneo di Fisica, Universita di Bari, Via Amendola 173, 70126 Bari (Italy); Capozzi, V. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, 71100 Foggia (Italy)], E-mail: v.capozzi@unifg.it

    2009-01-15

    We report a detailed investigation of fluorescence properties of synthetic eumelanin pigment in solution. A complete set of fluorescence spectra in the near-UV and visible range is analysed. Excitation spectra at a few selected emission energies are also investigated. Our measurements support the hypothesis that fluorescence in eumelanin is related to chemically distinct oligomeric units that can be selectively excited. Fluorescence due to large oligomer systems is spectrally differentiated from that due to monomers and small oligomer systems. Fluorescence excitation measurements show the contribution of 5,6-dihydroxyndole-2-carboxylic acid and 5,6-dihydroxyndole monomers to the emission of small-size oligomers.

  4. Expression of strain tensor in orthogonal curvilinear coordinates

    Directory of Open Access Journals (Sweden)

    Xuyan Liu

    2010-01-01

    Full Text Available Based on an analysis of connotation and extension of the concept of the orthogonal curvilinear coordinates, we have deduced a platform of strain tensor expression of Cartesian coordinates, which turns out to be a function of Lame coefficient and unit vector. By using transform matrix between Cartesian coordinates and orthogonal curvilinear coordinates, we have deduced a mathematical expression for correcting displacement vector differential in orthogonal curvilinear coordinates, and given a general expression of strain tensor in orthogonal curvilinear coordinates.

  5. Zn(II)-Coordinated Quantum Dot-FRET Nanosensors for the Detection of Protein Kinase Activity.

    Science.gov (United States)

    Lim, Butaek; Park, Ji-In; Lee, Kyung Jin; Lee, Jin-Won; Kim, Tae-Wuk; Kim, Young-Pil

    2015-07-23

    We report a simple detection of protein kinase activity using Zn(II)-mediated fluorescent resonance energy transfer (FRET) between quantum dots (QDs) and dye-tethered peptides. With neither complex chemical ligands nor surface modification of QDs, Zn(II) was the only metal ion that enabled the phosphorylated peptides to be strongly attached on the carboxyl groups of the QD surface via metal coordination, thus leading to a significant FRET efficiency. As a result, protein kinase activity in intermixed solution was efficiently detected by QD-FRET via Zn(II) coordination, especially when the peptide substrate was combined with affinity-based purification. We also found that mono- and di-phosphorylation in the peptide substrate could be discriminated by the Zn(II)-mediated QD-FRET. Our approach is expected to find applications for studying physiological function and signal transduction with respect to protein kinase activity.

  6. Interaction of fluorescent phospholipids with cyclodextrins.

    Science.gov (United States)

    Denz, Manuela; Haralampiev, Ivan; Schiller, Sabine; Szente, Lajos; Herrmann, Andreas; Huster, Daniel; Müller, Peter

    2016-01-01

    Fluorescent analogs of phospholipids are often employed to investigate the structure and dynamics of lipids in membranes. Some of those studies have used cyclodextrins e.g., to modulate the lipid phase. However, the role of the fluorescence moiety of analogs for the interaction between cyclodextrins and fluorescent lipids has not been investigated so far in detail. Therefore, in the present study the interaction of various fluorescent phospholipid analogs with methylated α-, β- and γ- cyclodextrins was investigated. The analogs differed in their structure, in the length of the fatty acyl chain, in the position of the fluorescence group, and in the attached fluorescence moiety (7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) or dipyrrometheneboron difluoride (BODIPY)). In aqueous buffer, cyclodextrins bind fluorescent lipids disturbing the organization of the analogs. When incorporated into lipid vesicles, analogs are selectively extracted from the membrane upon addition of cyclodextrins. The results show that the interaction of cyclodextrins with fluorescent phospholipids depends on the cyclodextrin species, the fluorescence moiety and the phospholipid structure. The presented data should be of interest for studies using fluorescent phospholipids and cyclodextrins, since the interaction between the fluorescence group and the cyclodextrin may interfere with the process(es) under study. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Basic investigation of concentrator using fluorescent substance

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, Mitsuo

    1986-12-01

    A concentrator was manufactured on an experimental basis to improve the performance of the concentrator using fluorescent substance and the analysis based on the test result of optical characteristics of the materials composing the concentrator was made. The concentrator is composed of fluorescent substance sandwiched between two acrylic sheets. Organic fluorescent solution prepared by dissolving eosin to alcohol and capsulating with transparent encapsulant was used as the fluorescent substance. The concentration ratio based on the characteristic tests of the fluorescent substance and material of acrylic sheet composing the concentrator and the numerical calculation model was calculated. The results show that the difference between the experimental and calculated values is 10%. The result of calculation based on the numerical model indicates that the energy efficiency is decreased through the concentration ratio is increased in a thin concentrator, because the fluorescence is decreased by the absorption during passing more frequently through the fluorescent layer. (1 ref, 10 figs)

  8. Coordination of soccer players during preseason training.

    Science.gov (United States)

    Tessitore, Antonio; Perroni, Fabrizio; Cortis, Cristina; Meeusen, Romain; Lupo, Corrado; Capranica, Laura

    2011-11-01

    This study aimed to verify whether coordination improves as a result of a preseason soccer training. During 5 experimental sessions (days 1, 6, 11, 15, and 19), 16 semiprofessional male soccer players (22.0 ± 3.6 years) were administered 3 specific soccer tests (speed dribbling, shooting a dead ball, and shooting from a pass) and an interlimb coordination test (total duration of a trial: 60 seconds), consisting of isodirectional and nonisodirectional synchronized (1:1 ratio) hand and foot flexions and extensions at an increasing velocity of execution (80, 120, and 180 b·min(-1)). Furthermore, subjective ratings were monitored to assess the recovery state (RestQ) of the players, their perceived exertion (rating of perceived exertion [RPE]) for the whole body, and the perceived muscle pain (rating of muscle pain [RMP]) for the lower limbs and the internal training load by means of the session-RPE method. The ratios between post and pretraining RPE and RMP increased only during the first 2 experimental sessions and decreased after the second week of the training camp (p = 0.001). The Rest-Q showed increases (p fatigue, physical complaints dimensions. Throughout the preseason, the players improved their speed dribbling (p = 0.03), Shooting from a Pass (p = 0.02), and interlimb coordination (p coordination tests succeeded in discriminating coordination in soccer players and could integrate field test batteries during the whole soccer season, because they were easily and inexpensively administrable by coaches.

  9. Coordination and standardization of federal sedimentation activities

    Science.gov (United States)

    Glysson, G. Douglas; Gray, John R.

    1997-01-01

    In August 1964, the Bureau of the Budget issued Circular A-67 to set forth guidelines for the coordination of water-data acquisition activities throughout the Federal government. The U.S. Department of the Interior was assigned the task of implementing Circular A-67, which in turn redelegated this responsibility to the U.S. Geological Survey (USGS). Delegation of the lead responsibility for water-data coordination to the USGS occurred because of its historical role as the primary agency for water-data acquisition in the United States. To provide overall leadership for implementing the provisions of Circular A-67, the USGS established the Office of Water Data Coordination in the Water Resources Division (WRD). In addition, regional and district offices of the WRD were delegated responsibility for coordinating water data within their geographic areas of responsibility. On December 10, 1991, the Office of Management and Budget issued OMB Number Memorandum M-92-01, which expands the USGS's coordination role to encompass all water information. This includes data critical to water resources in the following categories: - surface- and ground-water quality and quantity,

  10. Pseudoknot Formation Seeds the Twister Ribozyme Cleavage Reaction Coordinate.

    Science.gov (United States)

    Vušurović, Nikola; Altman, Roger B; Terry, Daniel S; Micura, Ronald; Blanchard, Scott C

    2017-06-21

    The twister RNA is a recently discovered nucleolytic ribozyme that is present in both bacteria and eukarya. While its biological role remains unclear, crystal structure analyses and biochemical approaches have revealed critical features of its catalytic mechanism. Here, we set out to explore dynamic aspects of twister RNA folding along the cleavage reaction coordinate. To do so, we have employed both bulk and single-molecule fluorescence resonance energy transfer (FRET) methods to investigate a set of twister RNAs with labels strategically positioned at communicating segments. The data reveal that folding of the central pseudoknot (T1), the most crucial structural determinant to promote cleavage, exhibits reversible opening and closing dynamics at physiological Mg2+ concentration. Uncoupled folding, in which T1 formation precedes structuring for closing of stem P1, was confirmed using pre-steady-state three-color smFRET experiments initiated by Mg2+ injection. This finding suggests that the folding path of twister RNA requires proper orientation of the substrate prior to T1 closure such that the U5-A6 cleavage site becomes embraced to achieve its cleavage competent conformation. We also find that the cleaved 3'-fragment retains its compacted pseudoknot fold, despite the absence of the phylogenetically conserved stem P1, rationalizing the poor turnover efficiency of the twister ribozyme.

  11. Fluorescent nanoparticles for intracellular sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ruedas-Rama, Maria J., E-mail: mjruedas@ugr.esmailto [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Walters, Jamie D. [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, UK CB2 1QT (United Kingdom); Orte, Angel [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Hall, Elizabeth A.H., E-mail: lisa.hall@biotech.cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT (United Kingdom)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. Black-Right-Pointing-Pointer Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. Black-Right-Pointing-Pointer Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  12. Far-Field Fluorescence Nanoscopy

    Science.gov (United States)

    Hell, Stefan

    2009-03-01

    The resolution of a far-field optical microscopy is usually limited to d=λ/ λ( 2,α ) . - ( 2,α ) > 200 nm, with nα denoting the numerical aperture of the lens and λ the wavelength of light. While the diffraction barrier has prompted the invention of electron, scanning probe, and x-ray microscopy, the 3D-imaging of the interior of (live) cells requires the use of focused visible light. I will discuss new developments of optical microscopy that I anticipate to have a lasting impact on our understanding of living matter. Emphasis will be placed on physical concepts that have overcome the diffraction barrier in far-field fluorescence microscopy. To set the scene for future directions, I will show that all these concepts share a common strategy: exploiting selected states and transitions of the fluorescent marker to neutralize the limiting role of diffraction. The first viable concept of this kind was Stimulated Emission Depletion (STED) microscopy where the spot diameter followsd λ/ λ( 2,α√1+I / I Is . - Is ) . - ( 2,α√1+I / I Is . - Is ); I / I Is . - Isis a measure of the strength with which the molecule is send from the fluorescent state to the dark ground state. For I / I Is . - Is->∞ it follows that d->0, meaning that the resolution that can, in principle, be molecular. The concept underlying STED microscopy can be expanded by employing other transitions that shuffle the molecule between a dark and a bright state, such as (i) shelving the fluorophore in a dark triplet state, and (ii) photoswitching between a `fluorescence activated' and a `fluorescence deactivated' conformational state. Examples for the latter include photochromic organic compounds, and fluorescent proteins which undergo a cis-trans photoisomerizations. Photoswitching provides ultrahigh resolution at ultralow light levels. Switching can be performed in an ensemble or individually in which case the image is assembled molecule by molecule at high resolution. By providing molecular

  13. Red and Green Fluorescence from Oral Biofilms.

    Directory of Open Access Journals (Sweden)

    Catherine M C Volgenant

    Full Text Available Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation as compared to the sucrose grown biofilms (cariogenic simulation. Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  14. Red and Green Fluorescence from Oral Biofilms.

    Science.gov (United States)

    Volgenant, Catherine M C; Hoogenkamp, Michel A; Krom, Bastiaan P; Janus, Marleen M; Ten Cate, Jacob M; de Soet, Johannes J; Crielaard, Wim; van der Veen, Monique H

    2016-01-01

    Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation) as compared to the sucrose grown biofilms (cariogenic simulation). Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red) were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.

  15. Obesity and Motor Coordination Ability in Taiwanese Children with and without Developmental Coordination Disorder

    Science.gov (United States)

    Zhu, Yi-Ching; Wu, Sheng K.; Cairney, John

    2011-01-01

    The purpose of this study was to investigate the associations between obesity and motor coordination ability in Taiwanese children with and without developmental coordination disorder (DCD). 2029 children (1078 boys, 951 girls) aged nine to ten years were chosen randomly from 14 elementary schools across Taiwan. We used bioelectrical impedance…

  16. Non-commutativity in polar coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, James P. [Universidad Michoacana de San Nicolas de Hidalgo, Ciudad Universitaria, Instituto de Fisica y Matematicas, Morelia, Michoacan (Mexico)

    2017-05-15

    We reconsider the fundamental commutation relations for non-commutative R{sup 2} described in polar coordinates with non-commutativity parameter θ. Previous analysis found that the natural transition from Cartesian coordinates to the traditional polar system led to a representation of [r, φ] as an everywhere diverging series. In this article we compute the Borel resummation of this series, showing that it can subsequently be extended throughout parameter space and hence provide an interpretation of this commutator. Our analysis provides a complete solution for arbitrary r and θ that reproduces the earlier calculations at lowest order and benefits from being generally applicable to problems in a two-dimensional non-commutative space. We compare our results to previous literature in the (pseudo-)commuting limit, finding a surprising spatial dependence for the coordinate commutator when θ >> r{sup 2}. Finally, we raise some questions for future study in light of this progress. (orig.)

  17. Relational Coordination in Danish General Practice

    DEFF Research Database (Denmark)

    Lundstrøm, Sanne Lykke

    and relationship networks through which work is coordinated across functional and organisational boundaries. Previous studies have shown that relational coordination is positively associated with delivery of care for patients with chronic illness. Organisational social capital is used when analysing...... the psychosocial work environment in organisations, and is seen as a powerful resources for improving organisational performance. Relational coordination and organisational social capital may oer new insight and opportunities for general practice to learn. General practice provides cost-efficient, first......This PhD dissertation is a product of my PhD project carried out in collaboration between DTU Management Engineering, The Technical University of Denmark, Research Unit for General Practice at University of Southern Denmark, and Research Unit for General Practice at University of Copenhagen...

  18. Impaired Visual Motor Coordination in Obese Adults.

    LENUS (Irish Health Repository)

    Gaul, David

    2016-09-01

    Objective. To investigate whether obesity alters the sensory motor integration process and movement outcome during a visual rhythmic coordination task. Methods. 88 participants (44 obese and 44 matched control) sat on a chair equipped with a wrist pendulum oscillating in the sagittal plane. The task was to swing the pendulum in synchrony with a moving visual stimulus displayed on a screen. Results. Obese participants demonstrated significantly (p < 0.01) higher values for continuous relative phase (CRP) indicating poorer level of coordination, increased movement variability (p < 0.05), and a larger amplitude (p < 0.05) than their healthy weight counterparts. Conclusion. These results highlight the existence of visual sensory integration deficiencies for obese participants. The obese group have greater difficulty in synchronizing their movement with a visual stimulus. Considering that visual motor coordination is an essential component of many activities of daily living, any impairment could significantly affect quality of life.

  19. TRUCE: A Coordination Action for Unconventional Computation

    DEFF Research Database (Denmark)

    Amos, M.; Stepney, S.; Doursat, R.

    2012-01-01

    , or mixtures of the two) as well as new paradigms which, for example, support combined information processing and material production (as living systems do). UCOMP researchers draw inspiration from a wide and diverse range of sources, from physics, to chemistry, biology and ecology. The field is growing...... and creative approaches, conceptual frameworks, mechanisms and perspectives. UCOMP offers one route towards this. TRUCE is a coordination action to help organize the international UCOMP community. The inherent diversity of the field has led to fragmentation, with many sub-fields developing in parallel....... With large-scale project support now being offered by the European Commission, the time is precisely right to organize and coordinate the field at the European level. This coordination action will engage the European community (and beyond), construct the first UCOMP roadmap, reach out to a wider public...

  20. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.