Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis

NASA Astrophysics Data System (ADS)

Tonannavar, J.; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B.; Patil, Nikhil A.; Mulimani, B. G.

2016-02-01

We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400 cm- 1) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis.

PubMed

Tonannavar, J; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B; Patil, Nikhil A; Mulimani, B G

2016-02-05

We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400c m(-1)) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH. Copyright © 2015 Elsevier B.V. All rights reserved.

Nanoparticle Nucleation Is Termolecular in Metal and Involves Hydrogen: Evidence for a Kinetically Effective Nucleus of Three {Ir3H2x·P2W15Nb3O62}6- in Ir(0)n Nanoparticle Formation From [(1,5-COD)IrI·P2W15Nb3O62]8- Plus Dihydrogen.

PubMed

Özkar, Saim; Finke, Richard G

2017-04-19

The nucleation process yielding Ir(0) ∼300 nanoparticles from (Bu 4 N) 5 Na 3 [(1,5-COD)Ir·P 2 W 15 Nb 3 O 62 ] (abbreviated hereafter as (COD)Ir·POM 8- , where POM 9- = the polyoxometalate, P 2 W 15 Nb 3 O 62 9- ) under H 2 is investigated to learn the true molecularity, and hence the associated kinetically effective nucleus (KEN), for nanoparticle formation for the first time. Recent work with this prototype transition-metal nanoparticle formation system ( J. Am. Chem. Soc. 2014 , 136 , 17601 - 17615 ) revealed that nucleation in this system is an apparent second-order in the precatalyst, A = (COD)Ir·POM 8- , not the higher order implied by classic nucleation theory and its nA ⇌ A n , "critical nucleus", A n concept. Herein, the three most reasonable more intimate mechanisms of nucleation are tested: bimolecular nucleation, termolecular nucleation, and a mechanism termed "alternative termolecular nucleation" in which 2(COD)Ir + and 1(COD)Ir·POM 8- yield the transition state of the rate-determining step of nucleation. The results obtained definitively rule out a simple bimolecular nucleation mechanism and provide evidence for the alternative termolecular mechanism with a KEN of 3, Ir 3 . All higher molecularity nucleation mechanisms were also ruled out. Further insights into the KEN and its more detailed composition involving hydrogen, {Ir 3 H 2x POM} 6- , are also obtained from the established role of H 2 in the Ir(0) ∼300 formation balanced reaction stoichiometry, from the p(H 2 ) dependence of the kinetics, and from a D 2 /H 2 kinetic isotope effect of 1.2(±0.3). Eight insights and conclusions are presented. A section covering caveats in the current work, and thus needed future studies, is also included.

193Ir Mössbauer spectroscopy of Pt-IrO 2 nanoparticle catalysts developed for detection and removal of carbon monoxide from air

NASA Astrophysics Data System (ADS)

Sawicki, J. A.; Marcinkowska, K.; Wagner, F. E.

2010-08-01

Mössbauer spectroscopy of 73.0 keV gamma-ray transition in 193Ir and supplementary analytical techniques were used to study the microstructure and chemical form of polymer-supported hydrophobic bimetallic Pt-Ir catalysts for detection and removal of CO from humid air at ambient conditions. The catalysts, typically with a composition of 9 wt.% Pt and 1 wt.% Ir, were prepared by incipient wetness impregnation of polystyrene-divinylbenzene (SDB) granules with ethanol solutions of hexachloroplatinic and hexachloroiridic acids. This procedure, followed by reduction in H 2 or CO at only 200 °C or 250 °C, resulted in formation of highly-dispersed Pt-Ir particles usually smaller than 20 nm and having high catalytic activity and selectivity. Mössbauer spectra of 73.0 keV gamma-ray transition in 193Ir were taken after consecutive steps of preparation and exposure of catalysts to better understand and further improve the fabrication processes. In the as-impregnated state, iridium was found mostly as Ir(III) in [IrCl 6] 3- ions, with only a small fraction of Ir(IV) in [IrCl 6] 2- ions. The iridium in bimetallic clusters formed by reduction in hydrogen showed a strong tendency towards oxidation on exposure to air at room temperature, while Pt remained mostly metallic. In the most active and stable catalysts, the Ir and Pt in metallic regions of the clusters did not tend to segregate, unlike in Pt-Ir/silica-supported catalysts studied by us earlier. Further, this study shows that the IrO 2-like regions in the clusters exhibit stronger deviations from local symmetry and stoichiometry of crystalline IrO 2 than observed previously in Pt-Ir/silica catalysts. Our study also indicates that in the examined Pt-IrO 2 nanoparticles iridium largely provides the dissociative O 2 adsorption sites, while the CO adsorption occurs primarily at metallic Pt sites.

IRS Spectral Maps of Photoevaporative Columns in M16, Carina, and the Galactic Center

NASA Astrophysics Data System (ADS)

Cotera, Angela; Healy, Kevin; Hester, Jeff; Sellgren, Kris; Simpson, Janet; Stolovy, Susan

2008-03-01

Photoevaporated columns of dust and gas - also called elephant trunks, pillars or fingers - are found in the periphery of H II regions, and have been observed within the Galaxy, the SMC and the LMC. These features are sites of current star formation, but the question remains whether the columns persist because stars formed in the denser regions prior to interactions with the UV radiation and stellar winds of nearby massive stars, or because of core collapse resulting from these interactions. Mapping the distribution of the physical states of the dust and gas in these columns is a necessary step towards understanding the possible star formation mechanisms within these dynamic objects. We propose to obtain IRS spectral maps of columns within M 16, the Carina nebula, and the Galactic center (GC) to understand the effects on these pillars from different stellar populations and initial conditions, and to better understand star formation in the GC. Within the spectral range of the high resolution IRS modes (9.9-37.2 micron) there are a wealth of molecular, atomic and PAH emission lines that will enable us to determine the excitation state, dust and gas temperatures, and probe the shock characteristics within the columns. Using the IRS spectral mapping mode, in conjunction with the CUBISM tool and the CLOUDY H II region model code, we will be able to construct detailed maps of the accessible emission lines and derived parameters for each column. IRS mapping of elephant trunks has not been done to date, yet provides a wealth of information unobtainable for the foreseeable future once Cycle 5 is completed.

Spitzer Space Telescope IRS Spectral Mapping of Photoionized Columns in M16 and the Carina HII Regions

NASA Astrophysics Data System (ADS)

Cotera, Angela; Simpson, J. P.; Sellgren, K.; Stolovy, S. R.

2013-01-01

Photoevaporated columns of dust and gas - also called elephant trunks, pillars or fingers - are found in the periphery of many H II regions. They have been observed within the Galaxy, the SMC and the LMC. These features are thought to be sites of current star formation, but the question remains whether the columns persist because stars formed in the denser regions prior to interactions with the UV radiation and stellar winds of nearby massive stars, or because of core collapse resulting from these interactions. We have obtained Spitzer IRS spectral maps of three columns within M 16 and three columns within the Carina nebula, to test our understanding of the impact on these transitory features of differing stellar populations and initial conditions. We use the wealth of molecular, atomic and PAH emission lines located within the spectral range of the high resolution IRS modes (9.9-37.2 micron) to determine the excitation state, dust and gas temperatures, and probe the shock characteristics within the columns as a function of location. Using the IRS spectral mapping mode, in conjunction with the CUBISM tool and the CLOUDY H II region model code, we have constructed detailed maps of the accessible emission lines and derived parameters for each column. Mapping the distribution of the physical states of the dust and gas in these columns is enhancing our understanding of the competing processes within these dynamic objects. The data presented here represent the only IRS spectral maps of photoionized pillars.

Constraining Cometary Crystal Shapes from IR Spectral Features

NASA Astrophysics Data System (ADS)

Wooden, D. H.; Lindsay, S.; Harker, D. E.; Kelley, M. S.; Woodward, C. E.; Murphy, J. R.

2013-12-01

A major challenge in deriving the silicate mineralogy of comets is ascertaining how the anisotropic nature of forsterite crystals affects the spectral features' wavelength, relative intensity, and asymmetry. Forsterite features are identified in cometary comae near 10, 11.05-11.2, 16, 19, 23.5, 27.5 and 33 μm [1-10], so accurate models for forsterite's absorption efficiency (Qabs) are a primary requirement to compute IR spectral energy distributions (SEDs, λFλ vs. λ) and constrain the silicate mineralogy of comets. Forsterite is an anisotropic crystal, with three crystallographic axes with distinct indices of refraction for the a-, b-, and c-axis. The shape of a forsterite crystal significantly affects its spectral features [13-16]. We need models that account for crystal shape. The IR absorption efficiencies of forsterite are computed using the discrete dipole approximation (DDA) code DDSCAT [11,12]. Starting from a fiducial crystal shape of a cube, we systematically elongate/reduce one of the crystallographic axes. Also, we elongate/reduce one axis while the lengths of the other two axes are slightly asymmetric (0.8:1.2). The most significant grain shape characteristic that affects the crystalline spectral features is the relative lengths of the crystallographic axes. The second significant grain shape characteristic is breaking the symmetry of all three axes [17]. Synthetic spectral energy distributions using seven crystal shape classes [17] are fit to the observed SED of comet C/1995 O1 (Hale-Bopp). The Hale-Bopp crystalline residual better matches equant, b-platelets, c-platelets, and b-columns spectral shape classes, while a-platelets, a-columns and c-columns worsen the spectral fits. Forsterite condensation and partial evaporation experiments demonstrate that environmental temperature and grain shape are connected [18-20]. Thus, grain shape is a potential probe for protoplanetary disk temperatures where the cometary crystalline forsterite formed. The

Observation and theory of reorientation-induced spectral diffusion in polarization-selective 2D IR spectroscopy.

PubMed

Kramer, Patrick L; Nishida, Jun; Giammanco, Chiara H; Tamimi, Amr; Fayer, Michael D

2015-05-14

In nearly all applications of ultrafast multidimensional infrared spectroscopy, the spectral degrees of freedom (e.g., transition frequency) and the orientation of the transition dipole are assumed to be decoupled. We present experimental results which confirm that frequency fluctuations can be caused by rotational motion and observed under appropriate conditions. A theory of the frequency-frequency correlation function (FFCF) observable under various polarization conditions is introduced, and model calculations are found to reproduce the qualitative trends in FFCF rates. The FFCF determined with polarization-selective two-dimensional infrared (2D IR) spectroscopy is a direct reporter of the frequency-rotational coupling. For the solute methanol in a room temperature ionic liquid, the FFCF of the hydroxyl (O-D) stretch decays due to spectral diffusion with different rates depending on the polarization of the excitation pulses. The 2D IR vibrational echo pulse sequence consists of three excitation pulses that generate the vibrational echo, a fourth pulse. A faster FFCF decay is observed when the first two excitation pulses are polarized perpendicular to the third pulse and the echo, 〈XXY Y〉, than in the standard all parallel configuration, 〈XXXX〉, in which all four pulses have the same polarization. The 2D IR experiment with polarizations 〈XY XY〉 ("polarization grating" configuration) gives a FFCF that decays even more slowly than in the 〈XXXX〉 configuration. Polarization-selective 2D IR spectra of bulk water do not exhibit polarization-dependent FFCF decays; spectral diffusion is effectively decoupled from reorientation in the water system.

Observation and theory of reorientation-induced spectral diffusion in polarization-selective 2D IR spectroscopy

NASA Astrophysics Data System (ADS)

Kramer, Patrick L.; Nishida, Jun; Giammanco, Chiara H.; Tamimi, Amr; Fayer, Michael D.

2015-05-01

In nearly all applications of ultrafast multidimensional infrared spectroscopy, the spectral degrees of freedom (e.g., transition frequency) and the orientation of the transition dipole are assumed to be decoupled. We present experimental results which confirm that frequency fluctuations can be caused by rotational motion and observed under appropriate conditions. A theory of the frequency-frequency correlation function (FFCF) observable under various polarization conditions is introduced, and model calculations are found to reproduce the qualitative trends in FFCF rates. The FFCF determined with polarization-selective two-dimensional infrared (2D IR) spectroscopy is a direct reporter of the frequency-rotational coupling. For the solute methanol in a room temperature ionic liquid, the FFCF of the hydroxyl (O-D) stretch decays due to spectral diffusion with different rates depending on the polarization of the excitation pulses. The 2D IR vibrational echo pulse sequence consists of three excitation pulses that generate the vibrational echo, a fourth pulse. A faster FFCF decay is observed when the first two excitation pulses are polarized perpendicular to the third pulse and the echo, , than in the standard all parallel configuration, , in which all four pulses have the same polarization. The 2D IR experiment with polarizations ("polarization grating" configuration) gives a FFCF that decays even more slowly than in the configuration. Polarization-selective 2D IR spectra of bulk water do not exhibit polarization-dependent FFCF decays; spectral diffusion is effectively decoupled from reorientation in the water system.

IR spectral analysis for the diagnostics of crust earthquake precursors

NASA Astrophysics Data System (ADS)

Umarkhodgaev, R. M.; Liperovsky, V. A.; Mikhailin, V. V.; Meister, C.-V.; Naumov, D. Ju

2012-04-01

In regions of future earthquakes, a few days before the seismic shock, the emanation of radon and hydrogen is being observed, which causes clouds of increased ionisation in the atmosphere. In the present work the possible diagnostics of these clouds using infrared (IR) spectroscopy is considered, which may be important and useful for the general geophysical system of earthquake prediction and the observation of industrial emissions of radioactive materials into the atmosphere. Some possible physical processes are analysed, which cause, under the condition of additional ionisation in a pre-breakdown electrical field, emissions in the IR interval. In doing so, the transparency region of the IR spectrum at wavelengths of 7-15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH4, CO2, N2O, NO2, NO, and O3. The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analysed. The laboratory equipment for the investigation of the IR absorption spectrum is constructed for the cases of normal and decreased atmospheric pressures. The syntheses of ozone and nitrous oxides are performed in the barrier discharge. It is studied if the products of the syntheses may be used to model atmospheric processes where these components take part. Spectra of products of the syntheses in the wavelength region of 2-10 μm are observed and analysed. A device is created for the syntheses and accumulation of nitrous oxides. Experiments to observe the IR-spectra of ozone and nitrous oxides during the syntheses and during the further evolution of these molecules are performed. For the earthquake prediction, practically, the investigation of emission spectra is most important, but during the laboratory experiments, the radiation of the excited molecules is shifted by a

Spectral Confirmation of New Galactic LBV and WN Stars Associated With Mid-IR Nebulae

NASA Astrophysics Data System (ADS)

Stringfellow, Guy; Gvaramadze, Vasilii V.

2014-08-01

Luminous Blue Variable (LBV) stars represent an extremely rare class and short-lived phase in the lives of very luminous massive stars with high mass loss rates. Extragalactic LBVs are responsible for producing false supernovae (SN), the SN Impostors, and have been directly linked with the progenitors of actual SN, indicating the LBV phase can be a final endpoint for massive star evolution. Yet only a few confirmed LBVs have been identified in the Galaxy. Their stellar evolution is poorly constrained by observations, and the physical reason for their unstable nature, both in terms of moderate spectral and photometric variability of a few magnitudes and the giant eruptions a la η Car that rival SN explosions, remains a mystery. Newly discovered mid-IR shells act as signposts, pointing to the central massive stars (LBV and Wolf-Rayet [WR] stars) that produced them. We have undertaken a spectroscopic survey of possible progenitor stars within these shells and are discovering that many are LBVs and WN-type WR transitional stars. We propose to extend this IR spectral survey to the south to search for new progenitor stars associated with dozens of newly identified shells. This survey should result in a substantial increase of new WRs and candidate LBVs for continued future study. Spectral analysis will yield new insights into the winds and physical properties of these rare and important objects, and lead to a better understanding of the physics driving giant eruptions.

Far-ultraviolet spectral changes of titanium dioxide with gold nanoparticles by ultraviolet and visible light

NASA Astrophysics Data System (ADS)

Tanabe, Ichiro; Kurawaki, Yuji

2018-05-01

Attenuated total reflectance spectra including the far-ultraviolet (FUV, ≤ 200 nm) region of titanium dioxide (TiO2) with and without gold (Au) nanoparticles were measured. A newly developed external light-irradiation system enabled to observe spectral changes of TiO2 with Au nanoparticles upon light irradiations. Absorption in the FUV region decreased and increased by the irradiation with ultraviolet and visible light, respectively. These spectral changes may reflect photo-induced electron transfer from TiO2 to Au nanoparticles under ultraviolet light and from Au nanoparticles to TiO2 under visible light, respectively.

Synthesis and spectral studies on Cd(II) dithiocarbamate complexes and their use as precursors for CdS nanoparticles

NASA Astrophysics Data System (ADS)

Sathiyaraj, Ethiraj; Padmavathy, Krishnaraj; Kumar, Chandran Udhaya; Krishnan, Kannan Gokula; Ramalingan, Chennan

2017-11-01

Bis(N-cyclopropyl-N-4-chlorobenzyldithiocarbamato-S,S‧)cadmium(II) (1) and (2,2‧-bipyridine) bis(N-cyclopropyl-N-4-chlorobenzyldithiocarbamato-S,S‧)cadmium(II) (2) have been synthesized and characterized by FT-IR, 1HNMR and 13C NMR analyses. For the complex 2, single crystal X-ray diffraction analysis and computational studies (optimized geometry, HOMO-LUMO and MEP) have been executed employing DFT/B3LYP method with LANL 2DZ basic set. The optimized bond lengths and bond angles agree well with the experimental results. The complexes 1 and 2 have been used as single source precursors for the synthesis of ethyleneglycol capped CdS1 and CdS2 nanoparticles, respectively. CdS1 and CdS2 nanoparticles have been synthesized by solvothermal method. PXRD, SEM, Elemental colour mapping, EDAX, TEM and UV-Vis spectroscopy have been used to characterize the as-prepared CdS nanoparticles. The X-ray diffraction pattern confirms both their hexagonal structures.

Synthesis and characterization of near IR fluorescent albumin nanoparticles for optical detection of colon cancer.

PubMed

Cohen, Sarit; Pellach, Michal; Kam, Yossi; Grinberg, Igor; Corem-Salkmon, Enav; Rubinstein, Abraham; Margel, Shlomo

2013-03-01

Near IR (NIR) fluorescent human serum albumin (HSA) nanoparticles hold great promise as contrast agents for tumor diagnosis. HSA nanoparticles are considered to be biocompatible, non-toxic and non-immunogenic. In addition, NIR fluorescence properties of these nanoparticles are important for in vivo tumor diagnostics, with low autofluorescence and relatively deep penetration of NIR irradiation due to low absorption of biomatrices. The present study describes the synthesis of new NIR fluorescent HSA nanoparticles, by entrapment of a NIR fluorescent dye within the HSA nanoparticles, which also significantly increases the photostability of the dye. Tumor-targeting ligands such as peanut agglutinin (PNA) and anti-carcinoembryonic antigen antibodies (anti-CEA) were covalently conjugated to the NIR fluorescent albumin nanoparticles, increasing the potential fluorescent signal in tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent HSA nanoparticles was demonstrated in a chicken embryo model and a rat model. In future work we also plan to encapsulate cancer drugs such as doxorubicin within the NIR fluorescent HSA nanoparticles for both colon cancer imaging and therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

EPR and IR spectral investigations on some leafy vegetables of Indian origin

NASA Astrophysics Data System (ADS)

Prasuna, C. P. Lakshmi; Chakradhar, R. P. S.; Rao, J. L.; Gopal, N. O.

2009-09-01

EPR spectral investigations have been carried out on four edible leafy vegetables of India, which are used as dietary component in day to day life. In Rumex vesicarius leaf sample, EPR spectral investigations at different temperatures indicate the presence of anti-ferromagnetically coupled Mn(IV)-Mn(IV) complexes. EPR spectra of Trigonella foenum graecum show the presence of Mn ions in multivalent state and Fe 3+ ions in rhombic symmetry. EPR spectra of Basella rubra indicate the presence of Mn(IV)-O-Mn(IV) type complexes. The EPR spectra of Basella rubra have been studied at different temperatures. It is found that the spin population for the resonance signal at g = 2.06 obeys the Boltzmann distribution law. The EPR spectra of Moringa oliefera leaves show the presence of Mn 2+ ions. Radiation induced changes in free radical of this sample have also been studied. The FT-IR spectra of Basella rubra and Moringa oliefera leaves show the evidences for the protein matrix bands and those corresponding to carboxylic C dbnd O bonds.

Far-ultraviolet spectral changes of titanium dioxide with gold nanoparticles by ultraviolet and visible light.

PubMed

Tanabe, Ichiro; Kurawaki, Yuji

2018-05-15

Attenuated total reflectance spectra including the far-ultraviolet (FUV, ≤200nm) region of titanium dioxide (TiO 2 ) with and without gold (Au) nanoparticles were measured. A newly developed external light-irradiation system enabled to observe spectral changes of TiO 2 with Au nanoparticles upon light irradiations. Absorption in the FUV region decreased and increased by the irradiation with ultraviolet and visible light, respectively. These spectral changes may reflect photo-induced electron transfer from TiO 2 to Au nanoparticles under ultraviolet light and from Au nanoparticles to TiO 2 under visible light, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Collisions of Ir Oxide Nanoparticles with Carbon Nanopipettes: Experiments with One Nanoparticle.

PubMed

Zhou, Min; Yu, Yun; Hu, Keke; Xin, Huolin L; Mirkin, Michael V

2017-03-07

Investigating the collisions of individual metal nanoparticles (NPs) with electrodes can provide new insights into their electrocatalytic behavior, mass transport, and interactions with surfaces. Here we report a new experimental setup for studying NP collisions based on the use of carbon nanopipettes to enable monitoring multiple collision events involving the same NP captured inside the pipet cavity. A patch clamp amplifier capable of measuring pA-range currents on the microsecond time scale with a very low noise and stable background was used to record the collision transients. The analysis of current transients produced by oxidation of hydrogen peroxide at one IrO x NP provided information about the origins of deactivation of catalytic NPs and the effects of various experimental conditions on the collision dynamics. High-resolution TEM of carbon pipettes was used to attain better understanding of the NP capture and collisions.

Collisions of Ir oxide nanoparticles with carbon nanopipettes: Experiments with one nanoparticle

DOE PAGES

Zhou, Min; Yu, Yun; Hu, Keke; ...

2017-02-03

Investigating the collisions of individual metal nanoparticles (NPs) with electrodes can provide new insights into their electrocatalytic behavior, mass transport, and interactions with surfaces. Here we report a new experimental setup for studying NP collisions based on the use of carbon nanopipettes to enable monitoring multiple collision events involving the same NP captured inside the pipet cavity. A patch clamp amplifier capable of measuring pA-range currents on the microsecond time scale with a very low noise and stable background was used to record the collision transients. The analysis of current transients produced by oxidation of hydrogen peroxide at one IrOxmore » NP provided information about the origins of deactivation of catalytic NPs and the effects of various experimental conditions on the collision dynamics. Lastly, high-resolution TEM of carbon pipettes was used to attain better understanding of the NP capture and collisions.« less

Electrochemical Catalyst-Support Effects and Their Stabilizing Role for IrOx Nanoparticle Catalysts during the Oxygen Evolution Reaction.

PubMed

Oh, Hyung-Suk; Nong, Hong Nhan; Reier, Tobias; Bergmann, Arno; Gliech, Manuel; Ferreira de Araújo, Jorge; Willinger, Elena; Schlögl, Robert; Teschner, Detre; Strasser, Peter

2016-09-28

Redox-active support materials can help reduce the noble-metal loading of a solid chemical catalyst while offering electronic catalyst-support interactions beneficial for catalyst durability. This is well known in heterogeneous gas-phase catalysis but much less discussed for electrocatalysis at electrified liquid-solid interfaces. Here, we demonstrate experimental evidence for electronic catalyst-support interactions in electrochemical environments and study their role and contribution to the corrosion stability of catalyst/support couples. Electrochemically oxidized Ir oxide nanoparticles, supported on high surface area carbons and oxides, were selected as model catalyst/support systems for the electrocatalytic oxygen evolution reaction (OER). First, the electronic, chemical, and structural state of the catalyst/support couple was compared using XANES, EXAFS, TEM, and depth-resolved XPS. While carbon-supported oxidized Ir particle showed exclusively the redox state (+4), the Ir/IrOx/ATO system exhibited evidence of metal/metal-oxide support interactions (MMOSI) that stabilized the metal particles on antimony-doped tin oxide (ATO) in sustained lower Ir oxidation states (Ir(3.2+)). At the same time, the growth of higher valent Ir oxide layers that compromise catalyst stability was suppressed. Then the electrochemical stability and the charge-transfer kinetics of the electrocatalysts were evaluated under constant current and constant potential conditions, where the analysis of the metal dissolution confirmed that the ATO support mitigates Ir(z+) dissolution thanks to a stronger MMOSI effect. Our findings raise the possibility that MMOSI effects in electrochemistry-largely neglected in the past-may be more important for a detailed understanding of the durability of oxide-supported nanoparticle OER catalysts than previously thought.

Dust Effects on Nucleation Kinetics and Nanoparticle Product Size Distributions: Illustrative Case Study of a Prototype Ir(0)n Transition-Metal Nanoparticle Formation System.

PubMed

Özkar, Saim; Finke, Richard G

2017-07-05

The question is addressed if dust is kinetically important in the nucleation and growth of Ir(0) n nanoparticles formed from [Bu 4 N] 5 Na 3 (1,5-COD)Ir I ·P 2 W 15 Nb 3 O 62 (hereafter [(COD)Ir·POM] 8- ), reduced by H 2 in propylene carbonate solvent. Following a concise review of the (often-neglected) literature addressing dust in nucleation phenomena dating back to the late 1800s, the nucleation and growth kinetics of the [(COD)Ir·POM] 8- precatalyst system are examined for the effects of 0.2 μm microfiltration of the solvent and precatalyst solution, of rinsing the glassware with that microfiltered solvent, of silanizing the glass reaction vessel, for the addition of <0.2 μm γ-Al 2 O 3 (inorganic) dust, for the addition of flame-made carbon-based (organic) dust, and as a function of the starting, microfiltered [(COD)Ir·POM 8- ] concentration. Efforts to detect dust and its removal by dynamic light scattering and by optical microscopy are also reported. The results yield a list of eight important conclusions, the four most noteworthy of which are (i) that the nucleation apparent rate "constant" k 1obs(bimol) is shown to be slowed by a factor of ∼5 to ∼7.6, depending on the precise experiment and its conditions, just by the filtration of the precatalyst solution using a 0.20 μm filter and rinsing the glassware surface with 0.20 μm filtered propylene carbonate solvent; (ii) that simply employing a 0.20 μm filtration step narrows the size distribution of the resulting Ir(0) n nanoparticles by a factor of 2.4 from ±19 to ±8%, a remarkable result; (iii) that the narrower size distribution can be accounted for by the slowed nucleation rate constant, k 1obs(bimol) , and by the unchanged autocatalytic growth rate constant, k 2obs(bimol) , that is, by the increased ratio of k 2obs(bimol) /k 1obs(bimol) that further separates nucleation from growth in time for filtered vs unfiltered solutions; and (iv) that five lines of evidence indicate that the

Effect of toxicity of Ag nanoparticles on SERS spectral variance of bacteria

NASA Astrophysics Data System (ADS)

Cui, Li; Chen, Shaode; Zhang, Kaisong

2015-02-01

Ag nanoparticles (NPs) have been extensively utilized in surface-enhanced Raman scattering (SERS) spectroscopy for bacterial identification. However, Ag NPs are toxic to bacteria. Whether such toxicity can affect SERS features of bacteria and interfere with bacterial identification is still unknown and needed to explore. Here, by carrying out a comparative study on non-toxic Au NPs with that on toxic Ag NPs, we investigated the influence of nanoparticle concentration and incubation time on bacterial SERS spectral variance, both of which were demonstrated to be closely related to the toxicity of Ag NPs. Sensitive spectral alterations were observed on Ag NPs with increase of NPs concentration or incubation time, accompanied with an obvious decrease in number of viable bacteria. In contrast, SERS spectra and viable bacterial number on Au NPs were rather constant under the same conditions. A further analysis on spectral changes demonstrated that it was cell response (i.e. metabolic activity or death) to the toxicity of Ag NPs causing spectral variance. However, biochemical responses to the toxicity of Ag were very different in different bacteria, indicating the complex toxic mechanism of Ag NPs. Ag NPs are toxic to a great variety of organisms, including bacteria, fungi, algae, protozoa etc., therefore, this work will be helpful in guiding the future application of SERS technique in various complex biological systems.

Engineering of near IR fluorescent albumin nanoparticles for in vivo detection of colon cancer.

PubMed

Cohen, Sarit; Margel, Shlomo

2012-08-14

The use of near-infrared (NIR) fluorescence imaging techniques has gained great interest for early detection of cancer because water and other intrinsic biomolecules display negligible absorption or autofluorescence in this region. Novel fluorescent nanoparticles with potential to improve neoplasm detection sensitivity may prove to be a valuable tool in early detection of colon tumors. The present study describes the synthesis and use of NIR fluorescent albumin nanoparticles as a diagnostic tool for detection of colon cancer. These fluorescent nanoparticles were prepared by a precipitation process of human serum albumin (HSA) in aqueous solution in the presence of a carboxylic acid derivative of the NIR dye IR-783 (CANIR). Tumor-targeting ligands such as peanut agglutinin (PNA), anti-carcinoembryonic antigen antibodies (anti-CEA) and tumor associated glycoprotein-72 monoclonal antibodies (anti-TAG-72) were covalently conjugated to the albumin nanoparticles via the surface carboxylate groups by using the carbodiimide activation method. Leakage of the encapsulated dye into PBS containing 4% HSA or human bowel juice was not detected. This study also demonstrates that the encapsulation of the NIR fluorescent dye within the HSA nanoparticles reduces the photobleaching of the dye significantly. Specific colon tumor detection in a mouse model was demonstrated for PNA, anti-CEA and anti-TAG-72 conjugated NIR fluorescent HSA nanoparticles. These bioactive NIR fluorescent albumin nanoparticles also detected invisible tumors that were revealed as pathological only subsequent to histological analysis. These results may suggest a significant advantage of NIR fluorescence imaging using NIR fluorescent nanoparticles over regular colonoscopy. In future work we plan to broaden this study by encapsulating cancer drugs, such as paclitaxel and doxorubicin, within these biodegradable NIR fluorescent HSA nanoparticles, in order to use them for both detection as well as therapy of colon

Engineering of near IR fluorescent albumin nanoparticles for in vivo detection of colon cancer

PubMed Central

2012-01-01

Background The use of near-infrared (NIR) fluorescence imaging techniques has gained great interest for early detection of cancer because water and other intrinsic biomolecules display negligible absorption or autofluorescence in this region. Novel fluorescent nanoparticles with potential to improve neoplasm detection sensitivity may prove to be a valuable tool in early detection of colon tumors. Methods The present study describes the synthesis and use of NIR fluorescent albumin nanoparticles as a diagnostic tool for detection of colon cancer. These fluorescent nanoparticles were prepared by a precipitation process of human serum albumin (HSA) in aqueous solution in the presence of a carboxylic acid derivative of the NIR dye IR-783 (CANIR). Tumor-targeting ligands such as peanut agglutinin (PNA), anti-carcinoembryonic antigen antibodies (anti-CEA) and tumor associated glycoprotein-72 monoclonal antibodies (anti-TAG-72) were covalently conjugated to the albumin nanoparticles via the surface carboxylate groups by using the carbodiimide activation method. Results and discussion Leakage of the encapsulated dye into PBS containing 4% HSA or human bowel juice was not detected. This study also demonstrates that the encapsulation of the NIR fluorescent dye within the HSA nanoparticles reduces the photobleaching of the dye significantly. Specific colon tumor detection in a mouse model was demonstrated for PNA, anti-CEA and anti-TAG-72 conjugated NIR fluorescent HSA nanoparticles. These bioactive NIR fluorescent albumin nanoparticles also detected invisible tumors that were revealed as pathological only subsequent to histological analysis. Conclusions These results may suggest a significant advantage of NIR fluorescence imaging using NIR fluorescent nanoparticles over regular colonoscopy. In future work we plan to broaden this study by encapsulating cancer drugs, such as paclitaxel and doxorubicin, within these biodegradable NIR fluorescent HSA nanoparticles, in order to

Blinking and spectral diffusion of CdSe/ZnS nanoparticles

NASA Astrophysics Data System (ADS)

Lorke, Axel; Braam, Daniel; Mölleken, Andreas; Offer, Matthias; Prinz, Günther; Geller, Martin

2012-02-01

Even though the tunable optical properties of colloidal nanoparticles have been studied extensively, their luminescent behaviour is still not fully understood. The random emission intermittency and the power-law of on- and off-times as well as shifts in the emission wavelength still lack a comprehensive understanding [1]. We investigate the excitonic structure of CdSe/ZnS core/shell nanoparticles using a micro-photoluminescence (PL) setup with confocal as well as imaging optics. The nanoparticles are dispersed in toluene with 1% PMMA and deposited by spin-coating on different substrates (bare Si/SiO2 as well as Si/SiO2 covered with different rough metallic layers). Depending on the substrate, we observe emission intermittency or nearly blinking-free emission with spectral jumps of 25 meV in the emission energy. Both can be assigned to excitonic transitions affected by additional charge inside or outside the nanoparticle [2]. Furthermore, we observe a phonon replica of 25 meV and smaller (<10 meV) energetic shifts of the emission lines, which are likely caused random charge variations in the environment of the nanoparticle. [4pt] [1] P. Frantsuzov et al., Nature 4, 519 (2008). [0pt] [2] A. Efros, Nature Mat. 7, 612 (2008)

Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

NASA Astrophysics Data System (ADS)

Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

2016-03-01

Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

Exchange bias of Ni nanoparticles embedded in an antiferromagnetic IrMn matrix.

PubMed

Kuerbanjiang, Balati; Wiedwald, Ulf; Haering, Felix; Biskupek, Johannes; Kaiser, Ute; Ziemann, Paul; Herr, Ulrich

2013-11-15

The magnetic properties of Ni nanoparticles (Ni-NPs) embedded in an antiferromagnetic IrMn matrix were investigated. The Ni-NPs of 8.4 nm mean diameter were synthesized by inert gas aggregation. In a second processing step, the Ni-NPs were in situ embedded in IrMn films or SiOx films under ultrahigh vacuum (UHV) conditions. Findings showed that Ni-NPs embedded in IrMn have an exchange bias field HEB = 821 Oe at 10 K, and 50 Oe at 300 K. The extracted value of the exchange energy density is 0.06 mJ m(-2) at 10 K, which is in good accordance with the results from multilayered thin film systems. The Ni-NPs embedded in SiOx did not show exchange bias. As expected for this particle size, they are superparamagnetic at T = 300 K. A direct comparison of the Ni-NPs embedded in IrMn or SiOx reveals an increase of the blocking temperature from 210 K to around 400 K. The coercivity of the Ni-NPs exchange coupled to the IrMn matrix at 10 K is 8 times larger than the value for Ni-NPs embedded in SiOx. We studied time-dependent remanent magnetization at different temperatures. The relaxation behavior is described by a magnetic viscosity model which reflects a rather flat distribution of energy barriers. Furthermore, we investigated the effects of different field cooling processes on the magnetic properties of the embedded Ni-NPs. Exchange bias values fit to model calculations which correlate the contribution of the antiferromagnetic IrMn matrix to its grain size.

Pullulan-coated phospholipid and Pluronic F68 complex nanoparticles for carrying IR780 and paclitaxel to treat hepatocellular carcinoma by combining photothermal therapy/photodynamic therapy and chemotherapy

PubMed Central

Zhang, Tao; Wan, Guoyun; Chen, Bowei; Xiong, Qingqing; Zhang, Jie; Zhang, Wenxue; Wang, Yinsong

2017-01-01

IR780, a near-infrared dye, can also be used as a photosensitizer both for photothermal therapy (PTT) and photodynamic therapy (PDT). In this study, we designed a simple but effective nanoparticle system for carrying IR780 and paclitaxel, thus hoping to combine PTT/PDT and chemotherapy to treat hepatocellular carcinoma (HCC). This nanosystem, named PDF nanoparticles, consisted of phospholipid/Pluronic F68 complex nanocores and pullulan shells. IR780 and paclitaxel were loaded separately into PDF nanoparticles to form PDFI and PDFP nanoparticles, which had regular sphere shapes and relatively small sizes. Upon near-infrared laser irradiation at 808 nm, PDFI nanoparticles showed strong PTT/PDT efficacy both in vitro and in vivo. In MHCC-97H cells, the combined treatment of PDFI nanoparticles/laser irradiation and PDFP nanoparticles exhibited significant synergistic effects on inhibiting cell proliferation and inducing cell apoptosis and cell cycle arrest at G2/M phase. In MHCC-97H tumor-bearing mice, PDFI nanoparticles exhibited excellent HCC-targeting and accumulating capability after intravenous injection. Furthermore, the combined treatment of PDFI nanoparticles/laser irradiation and PDFP nanoparticles also effectively inhibited the tumor growth and the tumor angiogenesis in MHCC-97H tumor-bearing mice. In summary, we put forward a therapeutic strategy for HCC treatment by combining PTT/PDT and chemotherapy. PMID:29255359

Pullulan-coated phospholipid and Pluronic F68 complex nanoparticles for carrying IR780 and paclitaxel to treat hepatocellular carcinoma by combining photothermal therapy/photodynamic therapy and chemotherapy.

PubMed

Wang, Dan; Zhang, Sipei; Zhang, Tao; Wan, Guoyun; Chen, Bowei; Xiong, Qingqing; Zhang, Jie; Zhang, Wenxue; Wang, Yinsong

2017-01-01

IR780, a near-infrared dye, can also be used as a photosensitizer both for photothermal therapy (PTT) and photodynamic therapy (PDT). In this study, we designed a simple but effective nanoparticle system for carrying IR780 and paclitaxel, thus hoping to combine PTT/PDT and chemotherapy to treat hepatocellular carcinoma (HCC). This nanosystem, named PDF nanoparticles, consisted of phospholipid/Pluronic F68 complex nanocores and pullulan shells. IR780 and paclitaxel were loaded separately into PDF nanoparticles to form PDFI and PDFP nanoparticles, which had regular sphere shapes and relatively small sizes. Upon near-infrared laser irradiation at 808 nm, PDFI nanoparticles showed strong PTT/PDT efficacy both in vitro and in vivo. In MHCC-97H cells, the combined treatment of PDFI nanoparticles/laser irradiation and PDFP nanoparticles exhibited significant synergistic effects on inhibiting cell proliferation and inducing cell apoptosis and cell cycle arrest at G2/M phase. In MHCC-97H tumor-bearing mice, PDFI nanoparticles exhibited excellent HCC-targeting and accumulating capability after intravenous injection. Furthermore, the combined treatment of PDFI nanoparticles/laser irradiation and PDFP nanoparticles also effectively inhibited the tumor growth and the tumor angiogenesis in MHCC-97H tumor-bearing mice. In summary, we put forward a therapeutic strategy for HCC treatment by combining PTT/PDT and chemotherapy.

Radical protection by differently composed creams in the UV/VIS and IR spectral ranges.

PubMed

Meinke, Martina C; Syring, Felicia; Schanzer, Sabine; Haag, Stefan F; Graf, Rüdiger; Loch, Manuela; Gersonde, Ingo; Groth, Norbert; Pflücker, Frank; Lademann, Jürgen

2013-01-01

Modern sunscreens are well suited to provide sufficient protection in the UV range because the filter substances absorb or scatter UV radiation. Although up to 50% of radicals are formed in the visible and infrared spectral range during solar radiation protection strategies are not provided in this range. Previous investigations of commercially available products have shown that in addition to physical filters, antioxidants (AO) are necessary to provide protective effects in the infrared range by neutralizing already formed radicals. In this study, the efficacy of filter substances and AO to reduce radical formation in both spectral ranges was investigated after UV/VIS or IR irradiation. Optical properties and radical protection were determined for the investigated creams. It was found that organic UV filters lower radical formation in the UV/VIS range to 35% compared to untreated skin, independent of the presence of AO. Further reduction to 14% was reached by addition of 2% physical filters, whereas physical filters alone were ineffective in the UV/VIS range due to the low concentration. In contrast, this filter type reduced radical formation in the IR range significantly to 65%; similar effects were aroused after application of AO. Sunscreens which contain organic UV filters, physical filters and AO ensure protection in the complete solar spectrum. © 2013 The American Society of Photobiology.

Calculation and experimental validation of spectral properties of microsize grains surrounded by nanoparticles.

PubMed

Yu, Haitong; Liu, Dong; Duan, Yuanyuan; Wang, Xiaodong

2014-04-07

Opacified aerogels are particulate thermal insulating materials in which micrometric opacifier mineral grains are surrounded by silica aerogel nanoparticles. A geometric model was developed to characterize the spectral properties of such microsize grains surrounded by much smaller particles. The model represents the material's microstructure with the spherical opacifier's spectral properties calculated using the multi-sphere T-matrix (MSTM) algorithm. The results are validated by comparing the measured reflectance of an opacified aerogel slab against the value predicted using the discrete ordinate method (DOM) based on calculated optical properties. The results suggest that the large particles embedded in the nanoparticle matrices show different scattering and absorption properties from the single scattering condition and that the MSTM and DOM algorithms are both useful for calculating the spectral and radiative properties of this particulate system.

The Effect of PtRuIr Nanoparticle Crystallinity in Electrocatalytic Methanol Oxidation

PubMed Central

Ma, Yanjiao; Wang, Rongfang; Wang, Hui; Liao, Shijun; Key, Julian; Linkov, Vladimir; Ji, Shan

2013-01-01

Two structural forms of a ternary alloy PtRuIr/C catalyst, one amorphous and one highly crystalline, were synthesized and compared to determine the effect of their respective structures on their activity and stability as anodic catalysts in methanol oxidation. Characterization techniques included TEM, XRD, and EDX. Electrochemical analysis using a glassy carbon disk electrode for cyclic voltammogram and chronoamperometry were tested in a solution of 0.5 mol L−1 CH3OH and 0.5 mol L−1 H2SO4. Amorphous PtRuIr/C catalyst was found to have a larger electrochemical surface area, while the crystalline PtRuIr/C catalyst had both a higher activity in methanol oxidation and increased CO poisoning rate. Crystallinity of the active alloy nanoparticles has a big impact on both methanol oxidation activity and in the CO poisoning rate. PMID:28809233

Phototoxic effect of conjugates of plasmon-resonance nanoparticles with indocyanine green dye on Staphylococcus aureus induced by IR laser radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuchina, E S; Tuchin, Valerii V; Khlebtsov, B N

2011-04-30

The effect of IR laser radiation ({lambda} = 805 - 808 nm) on the bacteria of the strain Staphylococcus aureus 209 P, incubated in indocyanine green solutions, is studied, as well as that of colloid gold nanoshells, nanocages and their conjugates with indocyanine green. It is found that the S. aureus 209 P cells are equally subjected to the IR laser radiation ({lambda} = 805 nm) after preliminary sensitisation with indocyanine green and gold nanoparticles separately and with conjugates of nanoparticles and indocyanine green. The enhancement of photodynamic and photothermal effects by 5 % is observed after 30 min ofmore » laser illumination ({lambda} = 808 nm) of bacteria, treated with conjugates of indocyanine green and nanocages. (optical technologies in biophysics and medicine)« less

Nonlinear-optical properties of thick composite media with vanadium dioxide nanoparticles. II. Self-focusing of mid-IR radiation

NASA Astrophysics Data System (ADS)

Vinogradova, O. P.; Ostrosablina, A. A.; Sidorov, A. I.

2006-02-01

This paper presents the experimental and theoretical results of a study of the interaction of pulsed laser radiation with thick composite media containing nanoparticles of vanadium dioxide (VO2). It is established that the reversible semiconductor-metal phase transition that occurs in the VO2 nanoparticles under the action of radiation can produce self-focusing of the mid-IR radiation by the formation of a photoinduced dynamic lens. An analysis is carried out of how the radiation intensity affects the dynamics of the given process.

The mid-IR spectral effects of darkening agents and porosity on the silicate surface features of airless bodies

NASA Astrophysics Data System (ADS)

Young, C. L.; Wray, J. J.; Poston, M.; Hand, K. P.; Carlson, R. W.

2017-12-01

The surfaces of airless bodies present opportunities to investigate the physical processes acting on planetary systems over time, without the need to account for surface-atmosphere interactions. Silicate surfaces mixed with fine-grained optically dark material with varying degrees of porosity are ubiquitous on many airless bodies (e.g., Earth's Moon, Deimos, Phobos, asteroids, meteorites, and moons of the outer solar system). Although the mid-IR is rich in emissivity features of important minerals and molecular groups, including organics [e.g., 1], it is less studied for airless conditions and presents challenges in signal-to-noise ratio, especially for the colder outer solar system bodies with fined-grained surfaces [2, 3]. We systematically measured the mid-IR spectra of different mixtures of three silicates (antigorite, lizardite, and pure silica) with varying porosities and amounts of darkening agent (iron oxide and carbon). Serpentines, such as antigorite and lizardite, are common to airless surfaces, and their mid-IR spectra in the presence of darkening agents and different surface porosities would be typical for those measured by spacecraft. Although pure silica has only been measured in the plumes of Enceladus, it presents exciting possibilities for other Saturn-system surfaces due to long range transport [4], and it is therefore important to investigate how its spectral signature would be manifested in the mid-IR. Overall, this work provides a library of mineral mixtures to facilitate dealing with current and future mid-IR datasets of airless bodies. These results are also applicable to the development of future missions to airless bodies, and our continuing efforts will help determine if mid-IR spectrometry is worthwhile for surface compositional studies of icy bodies. The mixtures presented here could be useful for testing future mid-IR instruments by confirming detectability of spectral features for typical materials on the surfaces of interest. [1

Optical element for full spectral purity from IR-generated EUV light sources

NASA Astrophysics Data System (ADS)

van den Boogaard, A. J. R.; Louis, E.; van Goor, F. A.; Bijkerk, F.

2009-03-01

Laser produced plasma (LLP) sources are generally considered attractive for high power EUV production in next generation lithography equipment. Such plasmas are most efficiently excited by the relatively long, infrared wavelengths of CO2-lasers, but a significant part of the rotational-vibrational excitation lines of the CO2 radiation will be backscattered by the plasma's critical density surface and consequently will be present as parasitic radiation in the spectrum of such sources. Since most optical elements in the EUV collecting and imaging train have a high reflection coefficient for IR radiation, undesirable heating phenomena at the resist level are likely to occur. In this study a completely new principle is employed to obtain full separation of EUV and IR radiation from the source by a single optical component. While the application of a transmission filter would come at the expense of EUV throughput, this technique potentially enables wavelength separation without loosing reflectance compared to a conventional Mo/Si multilayer coated element. As a result this method provides full spectral purity from the source without loss in EUV throughput. Detailed calculations on the principal of functioning are presented.

Silica nanoparticles for micro-particle imaging velocimetry: fluorosurfactant improves nanoparticle stability and brightness of immobilized iridium(III) complexes.

PubMed

Lewis, David J; Dore, Valentina; Rogers, Nicola J; Mole, Thomas K; Nash, Gerard B; Angeli, Panagiota; Pikramenou, Zoe

2013-11-26

To establish highly luminescent nanoparticles for monitoring fluid flows, we examined the preparation of silica nanoparticles based on immobilization of a cyclometalated iridium(III) complex and an examination of the photophysical studies provided a good insight into the Ir(III) microenvironment in order to reveal the most suitable silica nanoparticles for micro particle imaging velocimetry (μ-PIV) studies. Iridium complexes covalently incorporated at the surface of preformed silica nanoparticles, [Ir-4]@Si500-Z, using a fluorinated polymer during their preparation, demonstrated better stability than those without the polymer, [Ir-4]@Si500, as well as an increase in steady state photoluminescence intensity (and therefore particle brightness) and lifetimes which are increased by 7-fold compared with nanoparticles with the same metal complex attached covalently throughout their core, [Ir-4]⊂Si500. Screening of the nanoparticles in fluid flows using epi-luminescence microscopy also confirm that the brightest, and therefore most suitable particles for microparticle imaging velocimetry (μ-PIV) measurements are those with the Ir(III) complex immobilized at the surface with fluorosurfactant, that is [Ir-4]@Si500-Z. μ-PIV studies demonstrate the suitability of these nanoparticles as nanotracers in microchannels.

Tropospheric Ozone Near-Nadir-Viewing IR Spectral Sensitivity and Ozone Measurements from NAST-I

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Smith, William L.; Larar, Allen M.

2001-01-01

Infrared ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) from the NASA ER-2 aircraft (approximately 20 km altitude) with a spectral resolution of 0.25/cm were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented.

Formation mechanism of monodispersed spherical core-shell ceria/polymer hybrid nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izu, Noriya, E-mail: n-izu@aist.go.jp; Uchida, Toshio; Matsubara, Ichiro

2011-08-15

Graphical abstract: The formation mechanism for core-shell nanoparticles is considered to be as follows: nucleation and particle growth occur simultaneously (left square); very slow particle growth occurs (middle square). Highlights: {yields} The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the PVP molecular weight. {yields} The size of the nanoparticles increased by a 2-step process as the reflux heating time increased. {yields} The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. -- Abstract: Very unique core-shell ceria (ceriummore » oxide)/polymer hybrid nanoparticles that have monodispersed spherical structures and are easily dispersed in water or alcohol without the need for a dispersant were reported recently. The formation mechanism of the unique nanoparticles, however, was not clear. In order to clarify the formation mechanism, these nanoparticles were prepared using a polyol method (reflux heating) under varied conditions of temperature, time, and concentration and molecular weight of added polymer (poly(vinylpyrrolidone)). The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the poly(vinylpyrrolidone) molecular weight. Furthermore, the size of the nanoparticles increased by a 2-step process as the reflux heating time increased. The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. From these results, the formation mechanism was discussed and proposed.« less

Computational Design of Tunable UV-Vis-IR Filters Based on Silver Nanoparticle Arrays

NASA Astrophysics Data System (ADS)

Waters, Michael; Shi, Guangsha; Kioupakis, Emmanouil

We propose design strategies to develop selective optical filters in the UV-Vis-IR spectrum using the surface plasmon response of silver nanoparticle arrays. Our finite-difference time-domain simulations allow us to rapidly evaluate many nanostructures comprising simple geometries while varying their shape, height, width, and spacing. Our results allow us to identify trends in the filtering spectra as well as the relative amount of absorption and reflection. Optical filtering with nanoparticles is applicable to any transparent substrate and can be easily adapted to existing manufacturing processes while keeping the total cost of materials low. This work was supported by Guardian Industries Corp.

Detection and classification of salmonella serotypes using spectral signatures collected by fourier transform infrared (FT-IR) spectroscopy

USDA-ARS?s Scientific Manuscript database

Spectral signatures of Salmonella serotypes namely Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky were collected using Fourier transform infrared spectroscopy (FT-IR). About 5-10 µL of Salmonella suspensions with concentrations of 1...

Spectral dependence of fluorescence near plasmon resonant metal nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Yeechi

The optical properties of fluorophores are significantly modified when placed within the near field (0--100 nm) of plasmon resonant metal nanostructures, due to the competition between increased decay rates and "hotspots" of concentrated electric fields. The decay rates and effective electric field intensities are highly dependent on the relative position of dye and metal and the overlap between plasmon resonance and dye absorption and emission. Understanding these dependencies can greatly improve the performance of biosensing and nanophotonic devices. In this dissertation, the fluorescence intensity of organic dyes and CdSe quantum dots near single metal nanoparticles is studied as a function of the local surface plasmon resonance (LSPR) of the nanoparticle. Single metal nanoparticles have narrow, well-defined, intense local surface plasmon resonances that are tunable across the visible spectrum by changes in size and shape. First, we show that organic dyes can be self-assembled on single silver nanoprisms into known configurations by the hybridization of thiolated DNA oligomers. We correlate the fluorescence intensity of the dyes to the LSPR of the individual nanoprism to which they are attached. For each of three different organic dyes, we observe a strong correlation between the fluorescence intensity of the dye and the degree of spectral overlap with the plasmon resonance of the nanoparticle. On average, we observe the brightest fluorescence from dyes attached to metal nanoparticles that have a LSPR scattering peak 40--120 meV higher in energy than the emission peak of the fluorophore. Second, the plasmon-enhanced fluorescence from CdSe/CdS/CdZnS/ZnS core/shell quantum dots is studied near a variety of silver and gold nanoparticles. With single-particle scattering spectroscopy, the localized surface plasmon resonance spectra of single metal nanoparticles is correlated with the photoluminescence excitation (PLE) spectra of the nearby quantum dots. The PLE

Laser ablative decoration of micro-diamonds by gold nanoparticles for fabrication of hybrid plasmonic-dielectric antennae

NASA Astrophysics Data System (ADS)

Ivanova, A. K.; Ionin, A. A.; Khmelnitskii, R. A.; Kudryashov, S. I.; Levchenko, A. O.; Mel'nik, N. N.; Rudenko, A. A.; Saraeva, I. N.; Umanskaya, S. P.; Zayarny, D. A.; Nguyen, L. V.; Nguyen, T. T. H.; Pham, M. H.; Pham, D. V.; Do, T. H.

2017-06-01

Hybrid plasmonic-dielectric antennae are fabricated by laser ablation of gold in water sols of micro-diamonds. Electron microscopy and energy-dispersive x-ray spectroscopy of their deposits on a silicon wafer surface indicate close proximity of gold nanoparticles and micro-diamonds, which is supported by photoluminescence studies demonstrating strong (eight-fold) damping of micro-diamond luminescence owing to the attachment of the gold nanoparticles. UV-near-IR spectroscopy of their sols reveals a considerable plasmonic effect, related to red spectral shifts of surface plasmon resonance for the gold nanoparticles in the laser-ablation-fabricated antennae.

Multipolar response of nonspherical silicon nanoparticles in the visible and near-infrared spectral ranges

NASA Astrophysics Data System (ADS)

Terekhov, Pavel D.; Baryshnikova, Kseniia V.; Artemyev, Yuriy A.; Karabchevsky, Alina; Shalin, Alexander S.; Evlyukhin, Andrey B.

2017-07-01

Spectral multipole resonances of parallelepiped-, pyramid-, and cone-like shaped silicon nanoparticles excited by linearly polarized light waves are theoretically investigated. The numerical finite element method is applied for the calculations of the scattering cross sections as a function of the nanoparticles geometrical parameters. The roles of multipole moments (up to the third order) in the scattering process are analyzed using the semianalytical multipole decomposition approach. The possibility of scattering pattern configuration due to the tuning of the multipole contributions to the total scattered waves is discussed and demonstrated. It is shown that cubic nanoparticles can provide a strong isotropic side scattering with minimization of the scattering in forward and backward directions. In the case of the pyramidal and conical nanoparticles the total suppression of the side scattering can be obtained. It was found that due to the shape factor of the pyramidal and conical nanoparticles their electric toroidal dipole resonance can be excited in the spectral region of the first electric and magnetic dipole resonances. The influence of the incident light directions on the optical response of the pyramidal and conical nanoparticles is discussed. The obtained results provide important information that can be used for the development of nanoantennas with improved functionality due to the directional scattering effects.

The design and application of a multi-band IR imager

NASA Astrophysics Data System (ADS)

Li, Lijuan

2018-02-01

Multi-band IR imaging system has many applications in security, national defense, petroleum and gas industry, etc. So the relevant technologies are getting more and more attention in rent years. As we know, when used in missile warning and missile seeker systems, multi-band IR imaging technology has the advantage of high target recognition capability and low false alarm rate if suitable spectral bands are selected. Compared with traditional single band IR imager, multi-band IR imager can make use of spectral features in addition to space and time domain features to discriminate target from background clutters and decoys. So, one of the key work is to select the right spectral bands in which the feature difference between target and false target is evident and is well utilized. Multi-band IR imager is a useful instrument to collect multi-band IR images of target, backgrounds and decoys for spectral band selection study at low cost and with adjustable parameters and property compared with commercial imaging spectrometer. In this paper, a multi-band IR imaging system is developed which is suitable to collect 4 spectral band images of various scenes at every turn and can be expanded to other short-wave and mid-wave IR spectral bands combination by changing filter groups. The multi-band IR imaging system consists of a broad band optical system, a cryogenic InSb large array detector, a spinning filter wheel and electronic processing system. The multi-band IR imaging system's performance is tested in real data collection experiments.

Passive IR flexi-scope with two spectral colors for household screening of gastrointestinal disorders

NASA Astrophysics Data System (ADS)

Byrd, Kenneth; Szu, Harold

2006-04-01

According to our generalized Shannon Sampling Theorem of developmental system biology, we should increase the sampling frequency of the passive Infrared (IR) spectrum ratio test, (I 8~12mm / I 3~5mm). This procedure proved to be effective in DCIS using the satellite-grade IR spectrum cameras for an early developmental symptom of the "angiogenesis" effect. Thus, we propose to augment the annual hospital checkup of, or biannual Colonoscopy, with an inexpensive non-imaging IR-Flexi-scope intensity measurement device which could be conducted regularly at a household residence without the need doctoral expertise or a data basis system. The only required component would be a smart PC, which would be used to compute the degree of thermal activities through the IR spectral ratio. It will also be used to keep track of the record and send to the medical center for tele-diagnosis. For the purpose of household screening, we propose to have two integrated passive IR probes of dual-IR-color spectrum inserted into the body via the IR fiber-optic device. In order to extract the percentage of malignancy, based on the ratio of dual color IR measurements, the key enabler is the unsupervised learning algorithm in the sense of the Duda & Hart Unlabelled Data Classifier without lookup table exemplars. This learning methodology belongs to the Natural Intelligence (NI) of the human brain, which can effortlessly reduce the redundancy of pair inputs and thereby enhance the Signal to Noise Ratio (SNR) better than any single sensor for the salient feature extraction. Thus, we can go beyond a closed data basis AI expert system to tailor to the individual ground truth without the biases of the prior knowledge.

Tailoring plasmonic nanoparticles and fractal patterns

NASA Astrophysics Data System (ADS)

Rosa, Lorenzo; Juodkazis, Saulius

2011-12-01

We studied new three-dimensional tailoring of nano-particles by ion-beam and electron-beam lithographies, aiming for features and nano-gaps down to 10 nm size. Electron-beam patterning is demonstrated for 2D fabrication in combination with plasmonic metal deposition and lift-off, with full control of spectral features of plasmonic nano-particles and patterns on dielectric substrates. We present wide-angle bow-tie rounded nano-antennas whose plasmonic resonances achieve strong field enhancement at engineered wavelength range, and show how the addition of fractal patterns defined by standard electron beam lithography achieve light field enhancement from visible to far-IR spectral range and scalable up towards THz band. Field enhancement is evaluated by FDTD modeling on full-3D simulation domains using complex material models, showing the modeling method capabilities and the effect of staircase approximations on field enhancement and resonance conditions, especially at metal corners, where a minimum rounding radius of 2 nm is resolved and a five-fold reduction of spurious ringing at sharp corners is obtained by the use of conformal meshing.

Micromega/IR: Design and status of a near-infrared spectral microscope for in situ analysis of Mars samples

NASA Astrophysics Data System (ADS)

Leroi, Vaitua; Bibring, Jean-Pierre; Berthe, Michel

2009-07-01

MicrOmega is an ultra miniaturized spectral microscope for in situ analysis of samples. It is composed of 2 microscopes; one with a spatial sampling less or equal to 4 μm, working in 4 colors in the visible range: MicrOmega/VIS, and a NIR hyperspectral microscope working in the spectral range 0.9-4 μm with a spatial sampling of 20 μm per pixel: MicrOmega/IR (described in this paper). MicrOmega/IR illuminates and images samples a few mm in size and acquires the NIR spectrum of each resolved pixel in up to 320 contiguous spectral channels. The goal of this instrument is to analyze in situ the composition of collected samples at almost their grain size scale, in a non-destructive way. With the chosen spectral range and resolution, a wide variety of constituents can be identified: minerals, such as pyroxene and olivine, ferric oxides, hydrated phyllosilicates, sulfates and carbonates and ices and organics. The composition of the various phases within a given sample is a critical record of its formation and evolution. Coupled to the mapping information, it provides unique clues to describe the history of the parent body (planet, satellite and small body). In particular, the capability to identify hydrated grains and to characterize their adjacent phases has a huge potential in the search for possible bio-relics.

67P/CG morphological units and VIS-IR spectral classes: a Rosetta/VIRTIS-M perspective

NASA Astrophysics Data System (ADS)

Filacchione, Gianrico; Capaccioni, Fabrizio; Ciarniello, Mauro; Raponi, Andrea; De Sanctis, Maria Cristina; Tosi, Federico; Piccioni, Giuseppe; Cerroni, Priscilla; Capria, Maria Teresa; Palomba, Ernesto; Longobardo, Andrea; Migliorini, Alessandra; Erard, Stephane; Arnold, Gabriele; Bockelee-Morvan, Dominique; Leyrat, Cedric; Schmitt, Bernard; Quirico, Eric; Barucci, Antonella; McCord, Thomas B.; Stephan, Katrin; Kappel, David

2015-11-01

VIRTIS-M, the 0.25-5.1 µm imaging spectrometer on Rosetta (Coradini et al., 2007), has mapped the surface of 67P/CG nucleus since July 2014 from a wide range of distances. Spectral analysis of global scale data indicate that the nucleus presents different terrains uniformly covered by a very dark (Ciarniello et al., 2015) and dehydrated organic-rich material (Capaccioni et al., 2015). The morphological units identified so far (Thomas et al., 2015; El-Maarry et al., 2015) include dust-covered brittle materials regions (like Ash, Ma'at), exposed material regions (Seth), large-scale depressions (like Hatmehit, Aten, Nut), smooth terrains units (like Hapi, Anubis, Imhotep) and consolidated surfaces (like Hathor, Anuket, Aker, Apis, Khepry, Bastet, Maftet). For each of these regions average VIRTIS-M spectra were derived with the aim to explore possible connections between morphology and spectral properties. Photometric correction (Ciarniello et al., 2015), thermal emission removal in the 3.5-5 micron range and georeferencing have been applied to I/F data in order to derive spectral indicators, e.g. VIS-IR spectral slopes, their crossing wavelength (CW) and the 3.2 µm organic material band’s depth (BD), suitable to identify and map compositional variations. Our analysis shows that smooth terrains have the lower slopes in VIS (<1.7E-3 1/µm) and IR (0.4E-3 1/µm), CW=0.75 µm and BD=8-12%. Intermediate VIS slope=1.7-1.9E-3 1/µm, and higher BD=10-12.8%, are typical of consolidated surfaces, some dust covered regions and Seth where the maximum BD=13% has been observed. Large-scale depressions and Imhotep are redder with a VIS slope of 1.9-2.1E-3 1/µm, CW at 0.85-0.9 µm and BD=8-11%. The minimum VIS-IR slopes are observed above the Hapi, in agreement with the presence of water ice sublimation and recondensation processes observed by VIRTIS in this region (De Sanctis et al., 2015).Authors acknowledge ASI, CNES, DLR and NASA financial support.References:-Coradini et al

The Extreme Star Formation Activity of Arp 299 Revealed by Spitzer IRS Spectral Mapping

NASA Astrophysics Data System (ADS)

Alonso-Herrero, Almudena; Rieke, George H.; Colina, Luis; Pereira-Santaella, Miguel; García-Marín, Macarena; Smith, J.-D. T.; Brandl, Bernhard; Charmandaris, Vassilis; Armus, Lee

2009-05-01

We present Spitzer/IRS spectral mapping observations of the luminous infrared galaxy Arp 299 (IC 694 + NGC 3690) covering the central ~45'' ~ 9 kpc. The integrated mid-IR spectrum of Arp 299 is similar to that of local starbursts despite its strongly interacting nature and high-IR luminosity, L IR ~ 6 × 1011 L sun. This is explained because the star formation (probed by, e.g., high [Ne III]15.56 μm/[Ne II]12.81 μm line ratios) is spread across at least 6-8 kpc. Moreover, a large fraction of this star formation is taking place in young regions of moderate mid-IR optical depths such as the C+C' complex in the overlap region between the two galaxies and in H II regions in the disks of the galaxies. It is only source A, the nuclear region of IC 694, which shows the typical mid-IR characteristics of ultraluminous infrared galaxies (ULIRGs; L IR > 1012 L sun), that is, very compact (less than 1 kpc) and dust-enshrouded star formation resulting in a deep silicate feature and moderate equivalent widths of the polycyclic aromatic hydrocarbons. The nuclear region of NGC 3690, known as source B1, hosts a low-luminosity active galactic nucleus (AGN) and is surrounded by regions of star formation. Although the high-excitation [Ne V]14.32 μm line typical of AGN is not detected in B1, its upper limit is consistent with the value expected from the X-ray luminosity. The AGN emission is detected in the form of a strong hot-dust component that accounts for 80%-90% of the 6 μm luminosity of B1. The similarity between the Arp 299 integrated mid-IR spectrum and those of high-z ULIRGs suggests that Arp 299 may represent a local example, albeit with lower IR luminosity and possibly higher metallicity, of the star formation processes occurring at high-z. Based on observations obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407.

The influence of the spectral emissivity of flat-plate calibrators on the calibration of IR thermometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cárdenas-García, D.; Méndez-Lango, E.

Flat Calibrators (FC) are an option for calibration of infrared thermometers (IT) with a fixed large target. FCs are neither blackbodies, nor gray-bodies; their spectral emissivity is lower than one and depends on wavelength. Nevertheless they are used as gray-bodies with a nominal emissivity value. FCs can be calibrated radiometrically using as reference a calibrated IR thermometer (RT). If an FC will be used to calibrate ITs that work in the same spectral range as the RT then its calibration is straightforward: the actual FC spectral emissivity is not required. This result is valid for any given fixed emissivity assessedmore » to the FC. On the other hand, when the RT working spectral range does not match with that of the ITs to be calibrated with the FC then it is required to know the FC spectral emissivity as part of the calibration process. For this purpose, at CENAM, we developed an experimental setup to measure spectral emissivity in the infrared spectral range, based on a Fourier transform infrared spectrometer. Not all laboratories have emissivity measurement capability in the appropriate wavelength and temperature ranges to obtain the spectral emissivity. Thus, we present an estimation of the error introduced when the spectral range of the RT used to calibrate an FC and the spectral ranges of the ITs to be calibrated with the FC do not match. Some examples are developed for the cases when RT and IT spectral ranges are [8,13] μm and [8,14] μm respectively.« less

Catalytic performance of M@Ni (M = Fe, Ru, Ir) core-shell nanoparticles towards ammonia decomposition for CO x -free hydrogen production

NASA Astrophysics Data System (ADS)

Chen, Xin; Zhou, Junwei; Chen, Shuangjing; Zhang, Hui

2018-06-01

To reduce the use of precious metals and maintain the catalytic activity for NH3 decomposition reaction, it is an effective way to construct bimetallic nanoparticles with special structures. In this paper, by using density functional theory methods, we investigated NH3 decomposition reaction on three types of core-shell nanoparticles M@Ni (M = Fe, Ru, Ir) with 13 core M atoms and 42 shell Ni atoms. The size of these three particles is about 1 nm. Benefit from alloying with Ru in this nanocluster, Ru@Ni core-shell nanoparticles exhibit catalytic activity comparable to that of single metal Ru, based on the analysis of the adsorption energy and potential energy diagram of NH3 decomposition, as well as N2 desorption processes. However, as for Fe@Ni and Ir@Ni core-shell nanoparticles, their catalytic activities are still unsatisfactory compared to the active metal Ru. In addition, in order to further explain the synergistic effect of bimetallic core-shell nanoparticles, the partial density of states were also calculated. The results show that d-band electrons provided by the core metal are the main factors affecting the entire catalytic process.

IR spectral assignments for the hydrated excess proton in liquid water.

PubMed

Biswas, Rajib; Carpenter, William; Fournier, Joseph A; Voth, Gregory A; Tokmakoff, Andrei

2017-04-21

The local environmental sensitivity of infrared (IR) spectroscopy to a hydrogen-bonding structure makes it a powerful tool for investigating the structure and dynamics of excess protons in water. Although of significant interest, the line broadening that results from the ultrafast evolution of different solvated proton-water structures makes the assignment of liquid-phase IR spectra a challenging task. In this work, we apply a normal mode analysis using density functional theory of thousands of proton-water clusters taken from reactive molecular dynamics trajectories of the latest generation multistate empirical valence bond proton model (MS-EVB 3.2). These calculations are used to obtain a vibrational density of states and IR spectral density, which are decomposed on the basis of solvated proton structure and the frequency dependent mode character. Decompositions are presented on the basis of the proton sharing parameter δ, often used to distinguish Eigen and Zundel species, the stretch and bend character of the modes, the mode delocalization, and the vibrational mode symmetry. We find there is a wide distribution of vibrational frequencies spanning 1200-3000 cm -1 for every local proton configuration, with the region 2000-2600 cm -1 being mostly governed by the distorted Eigen-like configuration. We find a continuous red shift of the special-pair O⋯H + ⋯O stretching frequency, and an increase in the flanking water bending intensity with decreasing δ. Also, we find that the flanking water stretch mode of the Zundel-like species is strongly mixed with the flanking water bend, and the special pair proton oscillation band is strongly coupled with the bend modes of the central H 5 O2+moiety.

IR spectral assignments for the hydrated excess proton in liquid water

NASA Astrophysics Data System (ADS)

Biswas, Rajib; Carpenter, William; Fournier, Joseph A.; Voth, Gregory A.; Tokmakoff, Andrei

2017-04-01

The local environmental sensitivity of infrared (IR) spectroscopy to a hydrogen-bonding structure makes it a powerful tool for investigating the structure and dynamics of excess protons in water. Although of significant interest, the line broadening that results from the ultrafast evolution of different solvated proton-water structures makes the assignment of liquid-phase IR spectra a challenging task. In this work, we apply a normal mode analysis using density functional theory of thousands of proton-water clusters taken from reactive molecular dynamics trajectories of the latest generation multistate empirical valence bond proton model (MS-EVB 3.2). These calculations are used to obtain a vibrational density of states and IR spectral density, which are decomposed on the basis of solvated proton structure and the frequency dependent mode character. Decompositions are presented on the basis of the proton sharing parameter δ, often used to distinguish Eigen and Zundel species, the stretch and bend character of the modes, the mode delocalization, and the vibrational mode symmetry. We find there is a wide distribution of vibrational frequencies spanning 1200-3000 cm-1 for every local proton configuration, with the region 2000-2600 cm-1 being mostly governed by the distorted Eigen-like configuration. We find a continuous red shift of the special-pair O⋯H+⋯O stretching frequency, and an increase in the flanking water bending intensity with decreasing δ. Also, we find that the flanking water stretch mode of the Zundel-like species is strongly mixed with the flanking water bend, and the special pair proton oscillation band is strongly coupled with the bend modes of the central H5+O2 moiety.

IR spectral properties of dust and ice at the Mars south polar cap

NASA Astrophysics Data System (ADS)

Titus, T. N.; Kieffer, H. H.

2001-11-01

Removal of atmospheric dust effects is required to derive surface IR spectral emissivity. Commonly, the atmospheric-surface separation is based on radiative transfer (RT) spectral inversion methods using nadir-pointing observations. This methodology depends on a priori knowledge of the spectral shape of each atmospheric aerosol (e.g. dust or water ice) and a large thermal contrast between the surface and atmosphere. RT methods fail over the polar caps due to low thermal contrast between the atmosphere and the surface. We have used multi-angle Emission Phase Function (EPF) observations to estimate the opacity spectrum of dust over the springtime south polar cap and the underlying surface radiance, and thus, the surface emissivity. We include a few EPFs from Hellas Basin as a basis for comparisons between the spectral shape of polar and non-polar dust. Surface spectral emissivities over the seasonal cap are compared to CO2 models. Our results show that the spectral shape of the polar dust opacity is not constant, but is a two-parameter family that can be characterized by the 9 um and 20 um opacities. The 9 um opacity varies from 0.15 to 0.45 and characterizes the overall atmospheric conditions. The 9 um to 20 um opacity ratio varies from 2.0 to 5.1, suggesting changes in dust size distribution over the polar caps. Derived surface temperatures from the EPFs confirm that the slightly elevated temperatures (relative to CO2 frost temperature) observed in ``cryptic'' regions are a surface effect, not atmospheric. Comparison of broad-band reflectivity and surface emissivities to model spectra suggest the bright regions (e.g. perennial cap, Mountains of Mitchell) have higher albedos due to a thin surface layer of fine-grain CO2 (perhaps either frost or fractured ice) with an underlying layer of either coarse grain or slab CO2 ice.

Radiometric Cross-Calibration of the HJ-1B IRS in the Thermal Infrared Spectral Band

NASA Astrophysics Data System (ADS)

Sun, K.

2012-12-01

The natural calamities occur continually, environment pollution and destruction in a severe position on the earth presently, which restricts societal and economic development. The satellite remote sensing technology has an important effect on improving surveillance ability of environment pollution and natural calamities. The radiometric calibration is precondition of quantitative remote sensing; which accuracy decides quality of the retrieval parameters. Since the China Environment Satellite (HJ-1A/B) has been launched successfully on September 6th, 2008, it has made an important role in the economic development of China. The satellite has four infrared bands; and one of it is thermal infrared. With application fields of quantitative remote sensing in china, finding appropriate calibration method becomes more and more important. Many kinds of independent methods can be used to do the absolute radiometric calibration. In this paper, according to the characteristic of thermal infrared channel of HJ-1B thermal infrared multi-spectral camera, the thermal infrared spectral band of HJ-1B IRS was calibrated using cross-calibration methods based on MODIS data. Firstly, the corresponding bands of the two sensors were obtained. Secondly, the MONDTRAN was run to analyze the influences of different spectral response, satellite view zenith angle, atmosphere condition and temperature on the match factor. In the end, their band match factor was calculated in different temperature, considering the dissimilar band response of the match bands. Seven images of Lake Qinghai in different time were chosen as the calibration data. On the basis of radiance of MODIS and match factor, the IRS radiance was calculated. And then the calibration coefficients were obtained by linearly regressing the radiance and the DN value. We compared the result of this cross-calibration with that of the onboard blackbody calibration, which consistency was good.The maximum difference of brightness temperature

New format presentation for infrared spectral emittance data. Infrared spectrometry studies, phase 5

NASA Technical Reports Server (NTRS)

Lyon, R. J. P.; Green, A. A.

1972-01-01

Methods for infrared radiance measurements from geological materials were studied for airborne use over terrains with minimal vegetation. The tasks of the investigation were: (1) calculation of emittance ratios, (2) comparison of IR spectral emittance data with K-band scatterometer data over Pisgah Crater, and (3) standard infrared spectral file. Published papers reporting the research are included.

Nonlocal Coulomb correlations in pure and electron-doped Sr2IrO4 : Spectral functions, Fermi surface, and pseudo-gap-like spectral weight distributions from oriented cluster dynamical mean-field theory

NASA Astrophysics Data System (ADS)

Martins, Cyril; Lenz, Benjamin; Perfetti, Luca; Brouet, Veronique; Bertran, François; Biermann, Silke

2018-03-01

We address the role of nonlocal Coulomb correlations and short-range magnetic fluctuations in the high-temperature phase of Sr2IrO4 within state-of-the-art spectroscopic and first-principles theoretical methods. Introducing an "oriented-cluster dynamical mean-field scheme", we compute momentum-resolved spectral functions, which we find to be in excellent agreement with angle-resolved photoemission spectra. We show that while short-range antiferromagnetic fluctuations are crucial to accounting for the electronic properties of Sr2IrO4 even in the high-temperature paramagnetic phase, long-range magnetic order is not a necessary ingredient of the insulating state. Upon doping, an exotic metallic state is generated, exhibiting cuprate-like pseudo-gap spectral properties, for which we propose a surprisingly simple theoretical mechanism.

A calibration method for the measurement of IR detector spectral responses using a FTIR spectrometer equipped with a DTGS reference cell

NASA Astrophysics Data System (ADS)

Gravrand, Olivier; Wlassow, J.; Bonnefond, L.

2014-07-01

Various high performance IR detectors are today available on the market from QWIPs to narrow gap semiconductor photodiodes, which exhibit various spectral features. In the astrophysics community, the knowledge of the detector spectral shape is of first importance. This quantity (spectral QE or response) is usually measured by means of a monochromator followed by an integrating sphere and compared to a calibrated reference detector. This approach is usually very efficient in the visible range, where all optical elements are very well known, particularly the reference detector. This setup is also widely used in the near IR (up to 3μm) but as the wavelength increases, it becomes less efficient. For instance, the internal emittance of integrating spheres in the IR, and the bad knowledge of reference detectors for longer wavelengths tend to degrade the measurement reliability. Another approach may therefore be considered, using a Fourier transform IR spectrometer (FTIR). In this case, as opposed to the monochromator, the tested detector is not in low flux condition, the incident light containing a mix of different wavelengths. Therefore, the reference detector has to be to be sensitive (and known) in the whole spectral band of interest, because it will sense all those wavelengths at the same time. A popular detector used in this case is a Deuterated Triglycine Sulfate thermal detector (DTGS). Being a pyro detetector, the spectral response of such a detector is very flat, mainly limited by its window. However, the response of such a detector is very slow, highly depending on the temporal frequency of the input signal. Moreover, being a differential detector, it doesn't work in DC. In commercial FTIR spectrometers, the source luminance is usually continuously modulated by the moving interferometer, and the result is that the interferogram mixes optical spectral information (optical path difference) and temporal variations (temporal frequency) so that the temporal

Visualisation of distribution of gold nanoparticles in liver tissues ex vivo and in vitro using the method of optical coherence tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genina, Elina A; Terentyuk, G S; Khlebtsov, B N

2012-06-30

The possibility of visualising the distribution of gold nanoparticles in liver by means of the method of optical coherence tomography is studied experimentally in model samples of beef liver in vitro and rat liver ex vivo. In the experiments we used the gold nanoparticles in the form of nanocages with resonance absorption in the near-IR spectral region. In the model studies the suspension of nanoparticles was applied to the surface of the sample, which then was treated with ultrasound. In the ex vivo studies the suspension of nanoparticles was injected to the laboratory rats intravenously. The image contrast and themore » optical depth of detection of blood vessels and liver structure components are calculated, as well as the depth of liver optical probing before and after the injection of nanoparticles. It was shown that the administration of the nanoparticle increases significantly the imaging contrast of liver blood vessels owing to the localisation of the nanoparticles therein.« less

Optical phonon modes of III-V nanoparticles and indium phosphide/II-VI core-shell nanoparticles: A Raman and infrared study

NASA Astrophysics Data System (ADS)

Manciu, Felicia Speranta

The prospects for realizing efficient nanoparticle light emitters in the visible/near IR for communications and bio-medical applications have benefited from progress in chemical fabrication of nanoparticles. III-V semiconductor nanopaticles such as GaP and InP are promising materials for the development of "blue" and "green" emitters, respectively, due to their large effective bandgaps. Enhanced emission efficiency has been achieved for core-shell nanoparticles, since inorganic shell materials increase electronic tunability and may decrease surface defects that often occur for nanoparticles capped with organic molecules. Also, the emission wavelength of InP nanoparticle cores can be tuned from green to red by changing the shell material in InP/II-VI core-shell nanoparticles. Investigations of phonon modes in nanocrystals are of both fundamental and applied interest. In the former case the optical phonon modes, such as surface/interface modes, are dependent on the nanoparticle dimensions, and also can provide information about dynamical properties of the nanoparticles and test the validity of various theoretical approaches. In the latter case the vibronic properties of nanoparticle emitters are controlled by confined phonons and modifications of the electron-phonon interaction by the confinement. Thus, the objective of the present thesis is the detailed study of the phonon modes of III-V nanoparticles (GaP and InP) and InP/II-VI core-shell nanoparticles by IR absorption and Raman scattering spectroscopies, and an elucidation of their complex vibrational properties. With the exception of three samples (two GaP and one InP), all samples were synthesized by a novel colloidal chemistry method, which does not requires added surfactant, but rather treatment of the corresponding precursors in octadecene noncoordinative solvent. Sample quality was characterized by ED, TEM and X-ray diffraction. Based on a comparison with a dielectric continuum model, the observed features

Experimental modeling of local laser hyperthermia using thermosensitive nanoparticles absorbing in NIR

NASA Astrophysics Data System (ADS)

Romanishkin, Igor D.; Grachev, Pavel V.; Pominova, Daria V.; Burmistrov, Ivan A.; Sildos, Ilmo; Vanetsev, Alexander S.; Orlovskaya, Elena O.; Orlovskii, Yuri V.; Loschenov, Victor B.; Ryabova, Anastasia V.

2018-04-01

In this work we investigated the use of composite crystalline core/shell nanoparticles LaF3:Nd3+(1%)@DyPO4 for fluorescence-based contactless thermometry, as well as laser-induced hyperthermia effect in optical model of biological tissue with modeled neoplasm. In preparation for this, a thermal calibration of the nanoparticles luminescence spectra was carried out. The results of the spectroscopic temperature measurement were compared to infrared thermal camera measurements. It showed that there is a significant difference between temperature recorded with IR camera and the actual temperature of the nanoparticles in the depth of the tissue model. The temperature calculated using the spectral method was up to 10 °C higher.

Principles, performance, and applications of spectral reconstitution (SR) in quantitative analysis of oils by Fourier transform infrared spectroscopy (FT-IR).

PubMed

García-González, Diego L; Sedman, Jacqueline; van de Voort, Frederik R

2013-04-01

Spectral reconstitution (SR) is a dilution technique developed to facilitate the rapid, automated, and quantitative analysis of viscous oil samples by Fourier transform infrared spectroscopy (FT-IR). This technique involves determining the dilution factor through measurement of an absorption band of a suitable spectral marker added to the diluent, and then spectrally removing the diluent from the sample and multiplying the resulting spectrum to compensate for the effect of dilution on the band intensities. The facsimile spectrum of the neat oil thus obtained can then be qualitatively or quantitatively analyzed for the parameter(s) of interest. The quantitative performance of the SR technique was examined with two transition-metal carbonyl complexes as spectral markers, chromium hexacarbonyl and methylcyclopentadienyl manganese tricarbonyl. The estimation of the volume fraction (VF) of the diluent in a model system, consisting of canola oil diluted to various extents with odorless mineral spirits, served as the basis for assessment of these markers. The relationship between the VF estimates and the true volume fraction (VF(t)) was found to be strongly dependent on the dilution ratio and also depended, to a lesser extent, on the spectral resolution. These dependences are attributable to the effect of changes in matrix polarity on the bandwidth of the ν(CO) marker bands. Excellent VF(t) estimates were obtained by making a polarity correction devised with a variance-spectrum-delineated correction equation. In the absence of such a correction, SR was shown to introduce only a minor and constant bias, provided that polarity differences among all the diluted samples analyzed were minimal. This bias can be built into the calibration of a quantitative FT-IR analytical method by subjecting appropriate calibration standards to the same SR procedure as the samples to be analyzed. The primary purpose of the SR technique is to simplify preparation of diluted samples such that

UNTANGLING THE NEAR-IR SPECTRAL FEATURES IN THE PROTOPLANETARY ENVIRONMENT OF KH 15D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arulanantham, Nicole A.; Herbst, William; Gilmore, Martha S.

2017-01-10

We report on Gemini/GNIRS observations of the binary T Tauri system V582 Mon (KH 15D) at three orbital phases. These spectra allow us to untangle five components of the system: the photosphere and magnetosphere of star B, the jet, scattering properties of the ring material, and excess near-infrared (near-IR) radiation previously attributed to a possible self-luminous planet. We confirm an early-K subgiant classification for star B and show that the magnetospheric He i emission line is variable, possibly indicating increased mass accretion at certain times. As expected, the H{sub 2} emission features associated with the inner part of the jetmore » show no variation with orbital phase. We show that the reflectance spectrum for the scattered light has a distinctive blue slope and spectral features consistent with scattering and absorption by a mixture of water and methane ice grains in the 1–50 μ m size range. This suggests that the methane frost line is closer than ∼5 au in this system, requiring that the grains be shielded from direct radiation. After correcting for features from the scattered light, jet, magnetosphere, and photosphere, we confirm the presence of leftover near-IR light from an additional source, detectable near minimum brightness. A spectral emission feature matching the model spectrum of a 10 M {sub J}, 1 Myr old planet is found in the excess flux, but other expected features from this model are not seen. Our observations, therefore, tentatively support the picture that a luminous planet is present within the system, although they cannot yet be considered definitive.« less

FT-IR spectroscopy study on cutaneous neoplasie

NASA Astrophysics Data System (ADS)

Crupi, V.; De Domenico, D.; Interdonato, S.; Majolino, D.; Maisano, G.; Migliardo, P.; Venuti, V.

2001-05-01

In this work we report a preliminary study of Fourier transform infrared spectroscopy on normal and neoplastic human skin samples suffering from two kinds of cancer, namely epithelioma and basalioma. The analyzed skin samples have been drawn from different parts of the human body, after biopsies. By performing a complex band deconvolution due to the complexity of the tissue composition, the analysis within the considered frequency region (900-4000 cm -1) of the collected IR spectra, allowed us, first of all, to characterize the presence of the pathologies and to show clear different spectral features passing from the normal tissue to the malignant one in particular within the region (1500-2000 cm -1) typical of the lipid bands.

Study of physical properties of metal oxide nanoparticles obtained in acoustoplasma discharge

NASA Astrophysics Data System (ADS)

Bulychev, N. A.; Kazaryan, M. A.; Zakharyan, A. R.; Bodryshev, V. V.; Kirichenko, M. N.; Shevchenko, S. N.; Yakunin, V. G.; Timoshenko, V. Y.; Bychenko, A. B.

2018-04-01

Nanoparticles of tungsten, copper, iron, and zinc oxides were synthesized in acoustoplasma discharge. Their size distribution was studied by electron microscopy and laser correlation spectroscopy. Ultrasound was found to narrow significantly the size distribution width of zinc oxide nanoparticles. Water suspensions of zinc oxide nanoparticles showed photoluminescence in red and near infrared spectral ranges, which makes them a promising material for luminescent diagnostics of biological systems.

Laboratory IR Studies and Astrophysical Implications of C2H2-Containing Binary Ices

NASA Technical Reports Server (NTRS)

Knez, C.; Moore, M.; Ferrante, R.; Hudson, R.

2012-01-01

Studies of molecular hot cores and protostellar environments have shown that the observed abundance of gas-phase acetylene (C2H2) cannot be matched by chemical models without the inclusion of C2H2 molecules subliming from icy grain mantles. Searches for infrared (IR) spectral features of solid-phase acetylene are under way, but few laboratory reference spectra of C2H2 in icy mixtures, which are needed for spectral fits to observational data, have been published. Here, we report a systematic study of the IR spectra of condensed-phase pure acetylene and acetylene in ices dominated by carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water (H2O). We present new spectral data for these ices, including band positions and intrinsic band strengths. For each ice mixture and concentration, we also explore the dependence of acetylene's nu5-band position (743 cm-1, 13.46 micrometers) and FWHM on temperature. Our results show that the nu5 feature is much more cleanly resolved in ices dominated by non-polar and low-polarity molecules, specifically CO, CO2, and CH4, than in mixtures dominated by H2O-ice. We compare our laboratory ice spectra with observations of a quiescent region in Serpens.

MMI-based MOEMS FT spectrometer for visible and IR spectral ranges

NASA Astrophysics Data System (ADS)

Al-Demerdash, Bassem M.; Medhat, Mostafa; Sabry, Yasser M.; Saadany, Bassam; Khalil, Diaa

2014-03-01

MEMS spectrometers have very strong potential in future healthcare and environmental monitoring applications, where Michelson interferometers are the core optical engine. Recently, MEMS Michelson interferometers based on using silicon interface as a beam splitter (BS) has been proposed [7, 8]. This allows having a monolithically-integrated on-chip FTIR spectrometer. However silicon BS exhibits high absorption loss in the visible range and high material dispersion in the near infrared (NIR) range. For this reason, we propose in this work a novel MOEMS interferometer allowing operation over wider spectral range covering both the infrared (IR) and the visible ranges. The proposed architecture is based on spatial splitting and combining of optical beams using the imaging properties of Multi-Mode Interference MMI waveguide. The proposed structure includes an optical splitter for spatial splitting an input beam into two beams and a combiner for spatial combining the two interferometer beams. A MEMS moveable mirror is provided to produce an optical path difference between the two beams. The new interferometer is fabricated using DRIE technology on an SOI wafer. The movable mirror is metalized and attached to a comb-drive actuator fabricated in the same lithography step in a self-aligned manner on chip. The novel interferometer is tested as a Fourier transform spectrometer. Red laser, IR laser and absorption spectra of different materials are measured with a resolution of 2.5 nm at 635-nm wavelength. The structure is a very compact one that allows its integration and fabrication on a large scale with very low cost.

Morphological and Spectral Characteristics of Hybrid Nanosystems Based on Mono- and Bimetallic Platinum Nanoparticles and Silver

NASA Astrophysics Data System (ADS)

Valueva, S. V.; Vylegzhanina, M. E.; Sukhanova, T. E.

2018-02-01

Morphological and spectral characteristics of hybrid nanosystems (NSes) based on mono- and bimetallic silver and platinum nanoparticles (NPs) stabilized by a cationic polyelectrolyte (CP), poly- N,N,N,N-trimethylmethacryloyloxyethylammonium methylsulfate, are determined via static/dynamic light scattering, UV spectroscopy, and atomic force microscopy. The formation of dense spherical polymolecular nanostructures is established. The possibility of controlling the morphological and spectral characteristics of the NS is shown by varying the nature and composition of NPs.

Highly Stable Bimetallic AuIr/TiO₂ Catalyst: Physical Origins of the Intrinsic High Stability against Sintering.

PubMed

Han, Chang Wan; Majumdar, Paulami; Marinero, Ernesto E; Aguilar-Tapia, Antonio; Zanella, Rodolfo; Greeley, Jeffrey; Ortalan, Volkan

2015-12-09

It has been a long-lived research topic in the field of heterogeneous catalysts to find a way of stabilizing supported gold catalyst against sintering. Herein, we report highly stable AuIr bimetallic nanoparticles on TiO2 synthesized by sequential deposition-precipitation. To reveal the physical origin of the high stability of AuIr/TiO2, we used aberration-corrected scanning transmission electron microscopy (STEM), STEM-tomography, and density functional theory (DFT) calculations. Three-dimensional structures of AuIr/TiO2 obtained by STEM-tomography indicate that AuIr nanoparticles on TiO2 have intrinsically lower free energy and less driving force for sintering than Au nanoparticles. DFT calculations on segregation behavior of AuIr slabs on TiO2 showed that the presence of Ir near the TiO2 surface increases the adhesion energy of the bimetallic slabs to the TiO2 and the attractive interactions between Ir and TiO2 lead to higher stability of AuIr nanoparticles as compared to Au nanoparticles.

Surface enhanced Raman spectral studies of 2-bromo-1,4-naphthoquinone.

PubMed

Geetha, K; Umadevi, M; Sathe, G V; Vanelle, P; Terme, T; Khoumeri, O

2015-03-05

Silver nanoparticles have been synthesized by a simple and inexpensive solution combustion method with urea as fuel. The structural and morphology of the silver nanoparticles were investigated through X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersion Spectra (EDS) techniques. Structural and morphological results confirmed the nanocrystalline nature of the silver nanoparticles. Density Functional Theory (DFT) calculations were also performed to study the ground and excited state behavior of 2-bromo-1,4-naphthoquinone (2-BrNQ) and 2-BrNQ on silver nanoparticles. Surface-Enhanced Raman Scattering (SERS) spectra of 2-BrNQ adsorbed on silver nanoparticles were investigated. The CO, CH in-plane bending and CBr stretching modes were enhanced in SERS spectrum with respect to normal Raman spectrum. The spectral analysis reveals that the 2-BrNQ adsorbed 'stand-on' orientation on the silver surface. Density Functional Theory (DFT) calculations are also performed to study the vibrational features of 2-BrNQ molecule and 2-BrNQ molecule on silver surface. Copyright © 2014 Elsevier B.V. All rights reserved.

Nonlinear optical properties of thick composite media with vanadium dioxide nanoparticles. I. Self-defocusing of radiation in the visible and near-IR regions

NASA Astrophysics Data System (ADS)

Ostrosablina, A. A.; Sidorov, A. I.

2005-07-01

This paper presents the experimental and theoretical results of a study of the interaction of pulsed laser radiation with thick composite media containing nanoparticles of vanadium dioxide (VO2). It establishes that the reversible semiconductor-metal phase transition that occurs in VO2 nanoparticles under the action of radiation can produce self-defocusing of radiation in the visible and near-IR regions because of the formation of a photoinduced dynamic lens. An analysis is carried out of how the radiation intensity affects the dynamics of these processes. It is shown that photoinduced absorption and scattering play a role in forming the nonlinear optical response.

Radiative heat pumping from the Earth using surface phonon resonant nanoparticles.

PubMed

Gentle, A R; Smith, G B

2010-02-10

Nanoparticles that have narrow absorption bands that lie entirely within the atmosphere's transparent window from 7.9 to 13 mum can be used to radiatively cool to temperatures that are well below ambient. Heating from incoming atmospheric radiation in the remainder of the Planck radiation spectrum, where the atmosphere is nearly "black", is reduced if the particles are dopants in infrared transmitting polymers, or in transmitting coatings on low emittance substrates. Crystalline SiC nanoparticles stand out with a surface phonon resonance from 10.5 to 13 mum clear of the atmospheric ozone band. Resonant SiO(2) nanoparticles are complementary, absorbing from 8 to 10 mum, which includes atmospheric ozone emissions. Their spectral location has made SiC nanoparticles in space dust a feature in ground-based IR astronomy. Optical properties are presented and subambient cooling performance analyzed for doped polyethylene on aluminum. A mixture of SiC and SiO(2) nanoparticles yields high performance cooling at low cost within a practical cooling rig.

Composite multilobe descriptors for cross-spectral recognition of full and partial face

NASA Astrophysics Data System (ADS)

Cao, Zhicheng; Schmid, Natalia A.; Bourlai, Thirimachos

2016-08-01

Cross-spectral image matching is a challenging research problem motivated by various applications, including surveillance, security, and identity management in general. An example of this problem includes cross-spectral matching of active infrared (IR) or thermal IR face images against a dataset of visible light images. A summary of recent developments in the field of cross-spectral face recognition by the authors is presented. In particular, it describes the original form and two variants of a local operator named composite multilobe descriptor (CMLD) for facial feature extraction with the purpose of cross-spectral matching of near-IR, short-wave IR, mid-wave IR, and long-wave IR to a gallery of visible light images. The experiments demonstrate that the variants of CMLD outperform the original CMLD and other recently developed composite operators used for comparison. In addition to different IR spectra, various standoff distances from close-up (1.5 m) to intermediate (50 m) and long (106 m) are also investigated. Performance of CMLD I to III is evaluated for each of the three cases of distances. The newly developed operators, CMLD I to III, are further utilized to conduct a study on cross-spectral partial face recognition where different facial regions are compared in terms of the amount of useful information they contain for the purpose of conducting cross-spectral face recognition. The experimental results show that among three facial regions considered in the experiments the eye region is the most informative for all IR spectra at all standoff distances.

The Effect of Inorganic Nanoparticles on the Luminescence Properties of the 5CB Liquid Crystal

NASA Astrophysics Data System (ADS)

Bezrodna, T. V.; Klishevich, G. V.; Curmei, N. D.; Melnyk, V. I.; Nesprava, V. V.

2017-09-01

The luminescence spectral characteristics of nanocomposites based on the 5CB liquid crystal with dispersions of inorganic particles of carbon nanotubes (CNTs), the mineral montmorillonite (MMT), and nanotubes of titanium dioxide TiO2 (TNT) were investigated in the temperature range of 4.3-300 K. The IR absorption spectra of the composites at room temperature in the region of 390-4000 cm-1 were studied. The dependence of the luminescent properties of the composites on the physical properties and parameters of the nanoparticles was studied. It was established that the longwave shift of the luminescence spectra of the composites in relation to the spectra of the pure liquid crystal is related to the specific surface area of the nanoparticles. The longwave shifts of the spectra at room and low temperatures are analyzed.

Spectral reflectance relationships to leaf water stress

NASA Technical Reports Server (NTRS)

Ripple, William J.

1986-01-01

Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

IR Spectroscopic signs of malignant neoplasms in the thyroid gland

NASA Astrophysics Data System (ADS)

Tolstorozhev, G. B.; Skornyakov, I. V.; Butra, V. A.

2012-03-01

We use Fourier transform IR spectroscopy to study thyroid tumor tissues which were removed during surgery. The IR spectra of the tissues with pathological foci are compared with data from histologic examination. In the region of N-H, C-H, and C = O stretching vibrations, the IR spectra of the tissues for thyroid cancer are different from the IR spectra of tissues without malignant formations. We identify the spectral signs of thyroid cancer. We show that IR analysis is promising for identification of thyroid pathology at the molecular level.

A study on the stability and green synthesis of silver nanoparticles using Ziziphora tenuior (Zt) extract at room temperature.

PubMed

Sadeghi, Babak; Gholamhoseinpoor, F

2015-01-05

Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles in a single-step green synthesis process. This biogenic reduction of metal ion to base metal is quite rapid, readily conducted at room temperature and pressure, and easily scaled up. Mediated Synthesis by plant extracts is environmentally benign. The involved reducing agents include the various water soluble plant metabolites (e.g. alkaloids, phenolic compounds, terpenoids) and co-enzymes. Silver (Ag) nanoparticles have the particular focus of plant-based syntheses. Extracts of a diverse range of Ziziphora tenuior (Zt) have been successfully used in making nanoparticles. The aim of this study was to investigate the antioxidant properties of this plant and its ability to synthesize silver nanoparticles. Z.tenuior leaves were used to prepare the aqueous extract for this study. Silver nanoparticles were characterized with different techniques such as UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 8 to 40 nm. FT-IR spectroscopy revealed that silver nanoparticles were functionalized with biomolecules that have primary amine group (NH₂), carbonyl group, -OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of silver nanoparticles with size of 38 nm. In addition to plant extracts, live plants can be used for the synthesis. Here were view the methods of making nanoparticles using plant extracts. The scanning electron microscopy (SEM) implies the right of forming silver nanoparticles. The results of TEM, SEM, FT-IR, UV-VIS and XRD confirm that the leaves extract of Zt can synthesis silver nanoparticles. Copyright © 2014 Elsevier B.V. All rights

UV-visible spectroscopic estimation of photodegradation of rhodamine-B dye using tin(IV) oxide nanoparticles.

PubMed

Sangami, G; Dharmaraj, N

2012-11-01

Nanocrystalline, tin(IV) oxide (SnO(2)) particles has been prepared by thermal decomposition of tin oxalate precursor obtained from the reactions of tin(IV) chloride and sodium oxalate using eggshell membrane (ESM). The as-prepared SnO(2) nanoparticles were characterized by thermal studies, transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman, FT-IR and UV-visible studies and used as a photocatalyst for the degradation of rhodamine-B (Rh-B) dye. The size of the prepared nanoparticles was in the range of 5-12nm as identified from the TEM images. Powder XRD data revealed the presence of a tetragonal, rutile crystalline phase of the tin(IV) oxide nanoparticles. Thermal analysis showed that the decomposition of tin oxalate precursor to yield the titled tin(IV) oxide nanoparticles was completed below 500°C. The extent of degradation of Rh-B in the presence of SnO(2) monitored by absorption spectral measurements demonstrated that 94.48% of the selected dye was degraded upon irradiation with UV light for 60 min. Copyright © 2012 Elsevier B.V. All rights reserved.

Data fusion of Landsat TM and IRS images in forest classification

Treesearch

Guangxing Wang; Markus Holopainen; Eero Lukkarinen

2000-01-01

Data fusion of Landsat TM images and Indian Remote Sensing satellite panchromatic image (IRS-1C PAN) was studied and compared to the use of TM or IRS image only. The aim was to combine the high spatial resolution of IRS-1C PAN to the high spectral resolution of Landsat TM images using a data fusion algorithm. The ground truth of the study was based on a sample of 1,020...

IR spectroscopic characteristics of cell cycle and cell death probed by synchrotron radiation based Fourier transform IR spectromicroscopy

NASA Technical Reports Server (NTRS)

Holman, H. Y.; Martin, M. C.; Blakely, E. A.; Bjornstad, K.; McKinney, W. R.

2000-01-01

Synchrotron radiation based Fourier transform IR (SR-FTIR) spectromicroscopy allows the study of individual living cells with a high signal to noise ratio. Here we report the use of the SR-FTIR technique to investigate changes in IR spectral features from individual human lung fibroblast (IMR-90) cells in vitro at different points in their cell cycle. Clear changes are observed in the spectral regions corresponding to proteins, DNA, and RNA as a cell changes from the G(1)-phase to the S-phase and finally into mitosis. These spectral changes include markers for the changing secondary structure of proteins in the cell, as well as variations in DNA/RNA content and packing as the cell cycle progresses. We also observe spectral features that indicate that occasional cells are undergoing various steps in the process of cell death. The dying or dead cell has a shift in the protein amide I and II bands corresponding to changing protein morphologies, and a significant increase in the intensity of an ester carbonyl C===O peak at 1743 cm(-1) is observed. Copyright John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 57: 329-335, 2000.

Determination of phenolic compounds using spectral and color transitions of rhodium nanoparticles.

PubMed

Gatselou, Vasiliki; Christodouleas, Dionysios C; Kouloumpis, Antonios; Gournis, Dimitrios; Giokas, Dimosthenis L

2016-08-17

This work reports a new approach for the determination of phenolic compounds based on their interaction with citrate-capped rhodium nanoparticles. Phenolic compounds (i.e., catechins, gallates, cinnamates, and dihydroxybenzoic acids) were found to cause changes in the size and localized surface plasmon resonance of rhodium nanoparticles, and therefore, give rise to analyte-specific spectral and color transitions in the rhodium nanoparticle suspensions. Upon reaction with phenolic compounds (mainly dithydroxybenzoate derivatives, and trihydroxybenzoate derivatives), new absorbance peaks at 350 nm and 450 nm were observed. Upon reaction with trihydroxybenzoate derivatives, however, an additional absorbance peak at 580 nm was observed facilitating the speciation of phenolic compounds in the sample. Both absorbance peaks at 450 nm and 580 nm increased with increasing concentration of phenolic compounds over a linear range of 0-500 μM. Detection limits at the mid-micromolar levels were achieved, depending on the phenolic compound involved, and with satisfactory reproducibility (<7.3%). On the basis of these findings, two rhodium nanoparticles-based assays for the determination of the total phenolic content and total catechin content were developed and applied in tea samples. The obtained results correlated favorably with commonly used methods (i.e., Folin-Ciocalteu and aluminum complexation assay). Not the least, the finding that rhodium nanoparticles can react with analytes and exhibit unique localized surface plasmon resonance bands in the visible region, can open new opportunities for developing new optical and sensing analytical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Adsorption of collagen to indium oxide nanoparticles and infrared emissivity study thereon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou Yuming; Shan Yun; Sun Yanqing

Adsorption of collagen to indium oxide nanoparticles was carried out in water-acetone solution at volumetric ratio of 1:1 with pH value varying from 3.2 to 9.3. As indicated by TGA, maximum collagen adsorption to indium oxide nanoparticles occurred at pH of 3.2. It was proposed that noncovalent interactions such as hydrogen bonding, hydrophilic and electrostatic interactions made main contributions to collagen adsorption. The IR emissivity values (8-14 {mu}m) of collagen-adsorbed indium oxide nanoparticles decreased significantly compared to either pure collagen or indium oxide nanoparticles possibly due to the interfacial interactions between collagen and indium oxide nanoparticles. And the lowest infraredmore » emissivity value of 0.587 was obtained at collagen adsorption of 1.94 g/100 g In{sub 2}O{sub 3}. On the chance of improved compatibility with organic adhesives, the chemical activity of adsorbed collagen was further confirmed by grafting copolymerization with methyl methacrylate by formation of polymer shell outside, as evidenced by IR spectrum and transmission electron microscopy.« less

Spectroscopic studies of nanoparticle-sensitised photorefractive polymers

NASA Astrophysics Data System (ADS)

Aslam, Farzana; Binks, David J.; Daniels, Steve; Pickett, Nigel; O'Brien, Paul

2005-09-01

We report on the absorbance and photoluminescence spectra of photorefractive polymer composites sensitized by three different types of nanoparticles. Each nanoparticle is passivated by 1-hexadecylamine (HDA) and the composites also consist of the charge transporting matrix poly( N-vinylcarbazole) and the dye 1-(2'-ethylhexyloxy)-2,5-dimethyl-4-(4-nitrophenylazo) benzene. A strong spectral feature is observed that is attributed to a complex formed between the dye and HDA; elemental analysis indicates that the formation of this complex is determined by the metal content of the nanoparticle surface. The photoluminescence quantum yield for the complex is greatly reduced when the HDA is attached to the nanoparticle, indicating that a charge transfer occurs.

Interaction Between Cyanine Dye IR-783 and Polystyrene Nanoparticles in Solution.

PubMed

Zhang, Yunzhi; Xu, Hui; Casabianca, Leah B

2018-05-17

The interactions between small molecule drugs or dyes and nanoparticles are important to the use of nanoparticles in medicine. Noncovalent adsorption of dyes on nanoparticle surfaces is also important to the development of nanoparticle dual-use imaging contrast agents. In the present work, solution-state NMR is used to examine the noncovalent interaction between a near-infrared cyanine dye and the surface of polystyrene nanoparticles in solution. Using 1D proton NMR, we can approximate the number of dye molecules that associate with each nanoparticle for different sized nanoparticles. Saturation-Transfer Difference (STD)-NMR was also used to show that protons near the positively-charged nitrogen in the dye are more strongly associated with the negatively-charged nanoparticle surface than protons near the negatively-charged sulfate groups of the dye. The methods described here can be used to study similar drug or dye molecules interacting with the surface of organic nanoparticles. This article is protected by copyright. All rights reserved.

Simultaneous multi-beam planar array IR (pair) spectroscopy

DOEpatents

Elmore, Douglas L.; Rabolt, John F.; Tsao, Mei-Wei

2005-09-13

An apparatus and method capable of providing spatially multiplexed IR spectral information simultaneously in real-time for multiple samples or multiple spatial areas of one sample using IR absorption phenomena requires no moving parts or Fourier Transform during operation, and self-compensates for background spectra and degradation of component performance over time. IR spectral information and chemical analysis of the samples is determined by using one or more IR sources, sampling accessories for positioning the samples, optically dispersive elements, a focal plane array (FPA) arranged to detect the dispersed light beams, and a processor and display to control the FPA, and display an IR spectrograph. Fiber-optic coupling can be used to allow remote sensing. Portability, reliability, and ruggedness is enhanced due to the no-moving part construction. Applications include determining time-resolved orientation and characteristics of materials, including polymer monolayers. Orthogonal polarizers may be used to determine certain material characteristics.

Composite multi-lobe descriptor for cross spectral face recognition: matching active IR to visible light images

NASA Astrophysics Data System (ADS)

Cao, Zhicheng; Schmid, Natalia A.

2015-05-01

Matching facial images across electromagnetic spectrum presents a challenging problem in the field of biometrics and identity management. An example of this problem includes cross spectral matching of active infrared (IR) face images or thermal IR face images against a dataset of visible light images. This paper describes a new operator named Composite Multi-Lobe Descriptor (CMLD) for facial feature extraction in cross spectral matching of near-infrared (NIR) or short-wave infrared (SWIR) against visible light images. The new operator is inspired by the design of ordinal measures. The operator combines Gaussian-based multi-lobe kernel functions, Local Binary Pattern (LBP), generalized LBP (GLBP) and Weber Local Descriptor (WLD) and modifies them into multi-lobe functions with smoothed neighborhoods. The new operator encodes both the magnitude and phase responses of Gabor filters. The combining of LBP and WLD utilizes both the orientation and intensity information of edges. Introduction of multi-lobe functions with smoothed neighborhoods further makes the proposed operator robust against noise and poor image quality. Output templates are transformed into histograms and then compared by means of a symmetric Kullback-Leibler metric resulting in a matching score. The performance of the multi-lobe descriptor is compared with that of other operators such as LBP, Histogram of Oriented Gradients (HOG), ordinal measures, and their combinations. The experimental results show that in many cases the proposed method, CMLD, outperforms the other operators and their combinations. In addition to different infrared spectra, various standoff distances from close-up (1.5 m) to intermediate (50 m) and long (106 m) are also investigated in this paper. Performance of CMLD is evaluated for of each of the three cases of distances.

Spectral Selectivity of Plasmonic Interactions between Individual Up-Converting Nanocrystals and Spherical Gold Nanoparticles.

PubMed

Piątkowski, Dawid; Schmidt, Mikołaj K; Twardowska, Magdalena; Nyk, Marcin; Aizpurua, Javier; Maćkowski, Sebastian

2017-08-04

We experimentally demonstrate strong spectral selectivity of plasmonic interaction that occurs between α-NaYF₄:Er 3+ /Yb 3+ nanocrystals, which feature two emission bands, and spherical gold nanoparticles, with plasmon frequency resonant with one of the emission bands. Spatially-resolved luminescence intensity maps acquired for individual nanocrystals, together with microsecond luminescence lifetime images, show two qualitatively different effects that result from the coupling between plasmon excitations in metallic nanoparticles and emitting states of the nanocrystals. On the one hand, we observe nanocrystals, whose emission intensity is strongly enhanced for both resonant and non-resonant bands with respect to the plasmon resonance. Importantly, this increase is accompanied with shortening of luminescence decays times. In contrast, a significant number of nanocrystals exhibits almost complete quenching of the emission resonant with the plasmon resonance of gold nanoparticles. Theoretical analysis indicates that such an effect can occur for emitters placed at distances of about 5 nm from gold nanoparticles. While under these conditions, both transitions experience significant increases of the radiative emission rates due to the Purcell effect, the non-radiative energy transfer between resonant bands results in strong quenching, which in that situation nullifies the enhancement.

Mars atmosphere studies with the SPICAM IR emission phase function observations

NASA Astrophysics Data System (ADS)

Trokhimovskiy, Alexander; Fedorova, Anna; Montmessin, Franck; Korablev, Oleg; Bertaux, Jean-Loup

Emission Phase Function (EPF) observations is a powerful tool for characterization of atmosphere and surface. EPF sequence provides the extensive coverage of scattering angles above the targeted surface location which allow to separate the surface and aerosol scattering, study a vertical distribution of minor species and aerosol properties. SPICAM IR instrument on Mars Express mission provides continuous atmospheric observations in near IR (1-1.7 mu) in nadir and limb starting from 2004. For the first years of SPICAM operation only a very limited number of EPFs was performed. But from the mid 2013 (Ls=225, MY31) SPICAM EPF observations become rather regular. Based on the multiple-scattering radiative transfer model SHDOM, we analyze equivalent depths of carbon dioxide (1,43 mu) and water vapour (1,38 mu) absorption bands and their dependence on airmass during observation sequence to get aerosol optical depths and properties. The derived seasonal dust opacities from near IR can be used to retrieve the size distribution from comparison with simultaneous results of other instruments in different spectral ranges. Moreover, the EPF observations of water vapour band allow to access poorly known H2O vertical distribution for different season and locations.

FT-IR spectroscopy characterization of schwannoma: a case study

NASA Astrophysics Data System (ADS)

Ferreira, Isabelle; Neto, Lazaro P. M.; das Chagas, Maurilio José; Carvalho, Luís. Felipe C. S.; dos Santos, Laurita; Ribas, Marcelo; Loddi, Vinicius; Martin, Airton A.

2016-03-01

Schwannoma are rare benign neural neoplasia. The clinical diagnosis could be improved if novel optical techniques are performed. Among these techniques, FT-IR is one of the currently techniques which has been applied for samples discrimination using biochemical information with minimum sample preparation. In this work, we report a case of a schwannoma in the cervical region. A histological examination described a benign process. An immunohistochemically examination demonstrated positivity to anti-S100 protein antibody, indicating a diagnosis of schwannoma. The aim of this analysis was to characterize FT-IR spectrum of the neoplastic and normal tissue in the fingerprint (1000-1800 cm-1) and high wavenumber region (2800-3600 cm-1). The IR spectra were collect from tumor tissue and normal nerve samples by a FT-IR spectrophotometer (Spotlight Perkin Elmer 400, USA) with 64 scans, and resolution of 4 cm-1. A total of twenty spectra were recorded (10 from schwannoma and 10 from nerve). Multivariate Analysis was used to classify the data. Through average and standard deviation analysis we observed that the main spectral change occurs at ≍1600 cm-1 (amide I) and ≍1400 cm-1 (amide III) in the fingerprint region, and in CH2/CH3 protein-lipids and OH-water vibrations for the high wavenumber region. In conclusion, FT-IR could be used as a technique for schwannoma analysis helping to establish specific diagnostic.

AOTF near-IR spectrometers for study of Lunar and Martian surface composition

NASA Astrophysics Data System (ADS)

Ivanov, A.; Korablev, O.; Mantsevich, S.; Vyazovetskiy, N.; Fedorova, A.; Evdokimova, N.; Stepanov, A.; Titov, A.; Kalinnikov, Y.; Kuzmin, R.; Kiselev, A.; Bazilevsky, A.; Bondarenko, A.; Dokuchaev, I.; Moiseev, P.; Victorov, A.; Berezhnoy, A.; Skorov, Y.; Bisikalo, D.; Velikodsky, Y.

2014-04-01

The series of the AOTF near-IR spectrometers is developed in Moscow Space Research Institute for study of Lunar and Martian surface composition in the vicinity of a lander or a rover. Lunar Infrared Spectrometer (LIS) is an experiment onboard Luna-Glob (launch in 2017) and Luna- Resurs (launch in 2019) Russian surface missions. It's a pencil-beam spectrometer to be pointed by a robotic arm of the landing module. The instrument's field of view (FOV) of 1° is co-aligned with the FOV(45°) of a stereo TV camera. Infrared Spectrometer for ExoMars (ISEM) is an experiment onboard ExoMars (launch in 2018) ESARoscosmos rover. It's spectrometer based on LIS with required redesign for ExoMars mission. The ISEM instrument is mounted on the rover's mast coaligned with the FOV (5°) of High Resolution camera (HRC). Spectrometers and are intended for study of the surface composition in the vicinity of the lander and rover. The spectrometers will provide measurements of selected surface areas in the spectral range of 1.15-3.3 μm. The spectral selection is provided by acoustooptic tunable filter (AOTF), which scans the spectral range sequentially. Electrical command of the AOTF allows selecting the spectral sampling, and permits a random access if needed.

Characterization of KCNE1 inside Lipodisq Nanoparticles for EPR Spectroscopic Studies of Membrane Proteins.

PubMed

Sahu, Indra D; Zhang, Rongfu; Dunagan, Megan M; Craig, Andrew F; Lorigan, Gary A

2017-06-01

EPR spectroscopic studies of membrane proteins in a physiologically relevant native membrane-bound state are extremely challenging due to the complexity observed in inhomogeneity sample preparation and dynamic motion of the spin-label. Traditionally, detergent micelles are the most widely used membrane mimetics for membrane proteins due to their smaller size and homogeneity, providing high-resolution structure analysis by solution NMR spectroscopy. However, it is often difficult to examine whether the protein structure in a micelle environment is the same as that of the respective membrane-bound state. Recently, lipodisq nanoparticles have been introduced as a potentially good membrane mimetic system for structural studies of membrane proteins. However, a detailed characterization of a spin-labeled membrane protein incorporated into lipodisq nanoparticles is still lacking. In this work, lipodisq nanoparticles were used as a membrane mimic system for probing the structural and dynamic properties of the integral membrane protein KCNE1 using site-directed spin labeling EPR spectroscopy. The characterization of spin-labeled KCNE1 incorporated into lipodisq nanoparticles was carried out using CW-EPR titration experiments for the EPR spectral line shape analysis and pulsed EPR titration experiment for the phase memory time (T m ) measurements. The CW-EPR titration experiment indicated an increase in spectral line broadening with the addition of the SMA polymer which approaches close to the rigid limit at a lipid to polymer weight ratio of 1:1, providing a clear solubilization of the protein-lipid complex. Similarly, the T m titration experiment indicated an increase in T m values with the addition of SMA polymer and approaches ∼2 μs at a lipid to polymer weight ratio of 1:2. Additionally, CW-EPR spectral line shape analysis was performed on six inside and six outside the membrane spin-label probes of KCNE1 in lipodisq nanoparticles. The results indicated significant

AgCl-doped CdSe quantum dots with near-IR photoluminescence.

PubMed

Kotin, Pavel Aleksandrovich; Bubenov, Sergey Sergeevich; Mordvinova, Natalia Evgenievna; Dorofeev, Sergey Gennadievich

2017-01-01

We report the synthesis of colloidal CdSe quantum dots doped with a novel Ag precursor: AgCl. The addition of AgCl causes dramatic changes in the morphology of synthesized nanocrystals from spherical nanoparticles to tetrapods and finally to large ellipsoidal nanoparticles. Ellipsoidal nanoparticles possess an intensive near-IR photoluminescence ranging up to 0.9 eV (ca. 1400 nm). In this article, we explain the reasons for the formation of the ellipsoidal nanoparticles as well as the peculiarities of the process. The structure, Ag content, and optical properties of quantum dots are also investigated. The optimal conditions for maximizing both the reaction yield and IR photoluminescence quantum yield are found.

THE ORION FINGERS: NEAR-IR SPECTRAL IMAGING OF AN EXPLOSIVE OUTFLOW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youngblood, Allison; Bally, John; Ginsburg, Adam, E-mail: allison.youngblood@colorado.edu

2016-06-01

We present near-IR (1.1–2.4 μ m) position–position–velocity cubes of the 500 year old Orion BN/KL explosive outflow with spatial resolution 1″ and spectral resolution 86 km s{sup −1}. We construct integrated intensity maps free of continuum sources of 15 H{sub 2} and [Fe ii] lines while preserving kinematic information of individual outflow features. Included in the detected H{sub 2} lines are the 1-0 S(1) and 1-0 Q(3) transitions, allowing extinction measurements across the outflow. Additionally, we present dereddened flux ratios for over two dozen outflow features to allow for the characterization of the true excitation conditions of the BN/KL outflow. All of themore » ratios show the dominance of the shock excitation of the H{sub 2} emission, although some features exhibit signs of fluorescent excitation from stellar radiation or J-type shocks. We also detect tracers of the PDR/ionization front north of the Trapezium stars in [O i] and [Fe ii] and analyze other observed outflows not associated with the BN/KL outflow.« less

Imaging of Biological Cells Using Luminescent Silver Nanoparticles

NASA Astrophysics Data System (ADS)

Kravets, Vira; Almemar, Zamavang; Jiang, Ke; Culhane, Kyle; Machado, Rosa; Hagen, Guy; Kotko, Andriy; Dmytruk, Igor; Spendier, Kathrin; Pinchuk, Anatoliy

2016-01-01

The application of luminescent silver nanoparticles as imaging agents for neural stem and rat basophilic leukemia cells was demonstrated. The experimental size dependence of the extinction and emission spectra for silver nanoparticles were also studied. The nanoparticles were functionalized with fluorescent glycine dimers. Spectral position of the resonance extinction and photoluminescence emission for particles with average diameters ranging from 9 to 32 nm were examined. As the particle size increased, the spectral peaks for both extinction and the intrinsic emission of silver nanoparticles shifted to the red end of the spectrum. The intrinsic photoluminescence of the particles was orders of magnitude weaker and was spectrally separated from the photoluminescence of the glycine dimer ligands. The spectral position of the ligand emission was independent of the particle size; however, the quantum yield of the nanoparticle-ligand system was size-dependent. This was attributed to the enhancement of the ligand's emission caused by the local electric field strength's dependence on the particle size. The maximum quantum yield determined for the nanoparticle-ligand complex was (5.2 ± 0.1) %. The nanoparticles were able to penetrate cell membranes of rat basophilic leukemia and neural stem cells fixed with paraformaldehyde. Additionally, toxicity studies were performed. It was found that towards rat basophilic leukemia cells, luminescent silver nanoparticles had a toxic effect in the silver atom concentration range of 10-100 μM.

GIFTS SM EDU Radiometric and Spectral Calibrations

NASA Technical Reports Server (NTRS)

Tian, J.; Reisse, R. a.; Johnson, D. G.; Gazarik, J. J.

2007-01-01

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument gathers measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the processing algorithms involved in the calibration. The calibration procedures can be subdivided into three categories: the pre-calibration stage, the calibration stage, and finally, the post-calibration stage. Detailed derivations for each stage are presented in this paper.

Inversion technique for IR heterodyne sounding of stratospheric constituents from space platforms

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Shapiro, G. L.; Alvarez, J. M.

1981-01-01

The techniques which have been employed for inversion of IR heterodyne measurements for remote sounding of stratospheric trace constituents usually rely on either geometric effects based on limb-scan observations (i.e., onion peel techniques) or spectral effects by using weighting functions corresponding to different frequencies of an IR spectral line. An experimental approach and inversion technique are discussed which optimize the retrieval of concentration profiles by combining the geometric and the spectral effects in an IR heterodyne receiver. The results of inversions of some synthetic CIO spectral lines corresponding to solar occultation limb scans of the stratosphere are presented, indicating considerable improvement in the accuracy of the retrieved profiles. The effects of noise on the accuracy of retrievals are discussed for realistic situations.

Inversion technique for IR heterodyne sounding of stratospheric constituents from space platforms.

PubMed

Abbas, M M; Shapiro, G L; Alvarez, J M

1981-11-01

The techniques which have been employed for inversion of IR heterodyne measurements for remote sounding of stratospheric trace constituents usually rely on either geometric effects based on limb-scan observations (i.e., onion peel techniques) or spectral effects by using weighting functions corresponding to different frequencies of an IR spectral line. An experimental approach and inversion technique are discussed which optimize the retrieval of concentration profiles by combining the geometric and the spectral effects in an IR heterodyne receiver. The results of inversions of some synthetic ClO spectral lines corresponding to solar occultation limb scans of the stratosphere are presented, indicating considerable improvement in the accuracy of the retrieved profiles. The effects of noise on the accuracy of retrievals are discussed for realistic situations.

Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe 1-xM xSi, M=Ir,Os

DOE PAGES

Delaire, O.; Al-Qasir, Iyad I.; May, Andrew F.; ...

2015-03-31

The vibrational behavior of heavy substitutional impurities (M=Ir,Os) in Fe 1-xM xSi (x = 0, 0.02, 0.04, 0.1) was investigated with a combination of inelastic neutron scattering (INS), transport measurements, and first-principles simulations. In this paper, our INS measurements on single-crystals mapped the four-dimensional dynamical structure factor, S(Q;E), for several compositions and temperatures. Our results show that both Ir and Os impurities lead to the formation of a weakly dispersive resonance vibrational mode, in the energy range of the acoustic phonon dispersions of the FeSi host. We also show that Ir doping, which introduces free carriers and increases electron-phonon coupling,more » leads to softened interatomic force-constants compared to doping with Os, which is isoelectronic to Fe. We analyze the phonon S(Q,E) from INS through a Green's function model incorporating the phonon self-energy based on first-principles density functional theory (DFT) simulations. Calculations of the quasiparticle spectral functions in the doped system reveal the hybridization between the resonance and the acoustic phonon modes. Finally, our results demonstrate a strong interaction of the host acoustic dispersions with the resonance mode, likely leading to the large observed suppression in lattice thermal conductivity.« less

Temporal spectral response of a corn canopy

NASA Technical Reports Server (NTRS)

Markham, B. L.; Kimes, D. S.; Tucker, C. J.; Mcmurtrey, J. E., III

1981-01-01

Techniques developed for the prediction of winter wheat yields from remotely sensed data indicating crop status over the growing season are tested for their applicability to corn. Ground-based spectral measurements in the Landsat Thematic Mapper bands 3 (0.62-0.69 microns), 4 (0.76-0.90 microns) and 5 (1.55-1.75 microns) were performed at one-week intervals throughout the growing season for 24 plots of corn, and analyzed to derive spectral ratios and normalized spectral differences of the IR and shortwave IR bands with the red. The ratios of the near IR and shortwave IR bands are found to provide the highest and most consistent correlations with corn yield and dry matter accumulation, however the value of band 5 could not be tested due to the absence of water stress conditions. Integration of spectral ratios over several dates improved the correlations over those of any single date by achieving a seasonal, rather than instantaneous, estimate of crop status. Results point to the desirability of further tests under other growth conditions to determine whether satellite-derived data will be useful in providing corn yield information.

Hydrogen peroxide-responsive copolyoxalate nanoparticles for detection and therapy of ischemia-reperfusion injury.

PubMed

Lee, Dongwon; Bae, Soochan; Ke, Qingen; Lee, Jiyoo; Song, Byungjoo; Karumanchi, S Ananth; Khang, Gilson; Choi, Hak Soo; Kang, Peter M

2013-12-28

The main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury is the generation of high level of hydrogen peroxide (H2O2). In this study, we report a novel diagnostic and therapeutic strategy for I/R injury based on H2O2-activatable copolyoxalate nanoparticles using a murine model of hind limb I/R injury. The nanoparticles are composed of hydroxybenzyl alcohol (HBA)-incorporating copolyoxalate (HPOX) that, in the presence of H2O2, degrades completely into three known and safe compounds, cyclohexanedimethanol, HBA and CO2. HPOX effectively scavenges H2O2 in a dose-dependent manner and hydrolyzes to release HBA which exerts intrinsic antioxidant and anti-inflammatory activities both in vitro and in vivo models of hind limb I/R. HPOX nanoparticles loaded with fluorophore effectively and robustly image H2O2 generated in hind limb I/R injury, demonstrating their potential for bioimaging of H2O2-associated diseases. Furthermore, HPOX nanoparticles loaded with anti-apoptotic drug effectively release the drug payload after I/R injury, exhibiting their effectiveness for a targeted drug delivery system for I/R injury. We anticipate that multifunctional HPOX nanoparticles have great potential as H2O2 imaging agents, therapeutics and drug delivery systems for H2O2-associated diseases. © 2013.

Studies on the chemical synthesis and characterization of lead oxide nanoparticles with different organic capping agents

NASA Astrophysics Data System (ADS)

Arulmozhi, K. T.; Mythili, N.

2013-12-01

Lead oxide (PbO) nanoparticles were chemically synthesized using Lead (II) acetate as precursor. The effects of organic capping agents such as Oleic acid, Ethylene Diamine Tetra Acetic acid (EDTA) and Cetryl Tri Methyl Butoxide (CTAB) on the size and morphology of the nanoparticles were studied. Characterization techniques such as X-ray diffraction (XRD), Fourier Transform-Infrared spectroscopy (FT-IR), Photoluminescence (PL) Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) were used to analyse the prepared nanoparticles for their physical, structural and optical properties. The characterization studies reveal that the synthesized PbO nanoparticles had well defined crystalline structure and sizes in the range of 25 nm to 36 nm for capping agents used and 40 nm for pure PbO nanoparticles.

ZnO nanoparticles as an efficient, heterogeneous, reusable, and ecofriendly catalyst for four-component one-pot green synthesis of pyranopyrazole derivatives in water.

PubMed

Sachdeva, Harshita; Saroj, Rekha

2013-01-01

An extremely efficient catalytic protocol for the synthesis of a series of pyranopyrazole derivatives developed in a one-pot four-component approach in the presence of ZnO nanoparticles as heterogeneous catalyst using water as a green solvent is reported. Greenness of the process is well instituted as water is exploited both as reaction media and medium for synthesis of catalyst. The ZnO nanoparticles exhibited excellent catalytic activity, and the proposed methodology is capable of providing the desired products in good yield (85-90%) and short reaction time. After reaction course, ZnO nanoparticles can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. All the synthesized compounds have been characterized on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral studies.

One-step green synthesis and characterization of plant protein-coated mercuric oxide (HgO) nanoparticles: antimicrobial studies

NASA Astrophysics Data System (ADS)

Das, Amlan Kumar; Marwal, Avinash; Sain, Divya; Pareek, Vikram

2015-03-01

The present study demonstrates the bioreductive green synthesis of nanosized HgO using flower extracts of an ornamental plant Callistemon viminalis. The flower extracts of Callistemon viminalis seem to be environmentally friendly, so this protocol could be used for rapid production of HgO. Till date, there is no report of synthesis of nanoparticles using flower extract of Callistemon viminalis. Mercuric acetate was taken as the metal precursor in the present experiment. The flower extract was found to act as a reducing as well as a stabilizing agent. The phytochemicals present in the flower extract act as reducing agent which include proteins, saponins, phenolic compounds, phytosterols, and flavonoids. FT-IR spectroscopy confirmed that the extract had the ability to act as a reducing agent and stabilizer for HgO nanoparticles. The formation of the plant protein-coated HgO nanoparticles was first monitored using UV-Vis absorption spectroscopy. The UV-Vis spectroscopy revealed the formation of HgO nanoparticles by exhibiting the typical surface plasmon absorption maxima at 243 nm. The average particle size formed ranges from 2 to 4 nm. The dried form of synthesized nanoparticles was further characterized using TGA, XRD, TEM, and FTIR spectroscopy. FT-IR spectra of synthesized HgO nanoparticles were performed to identify the possible bio-molecules responsible for capping and stabilization of nanoparticles, which confirm the formation of plant protein-coated HgO nanoparticles that is further corroborated by TGA study. The optical band gap of HgO nanoparticle was measured to be 2.48 eV using cutoff wavelength which indicates that HgO nanoparticles can be used in metal oxide semiconductor-based photovoltaic cells. A possible core-shell structure of the HgO nanobiocomposite has been proposed.

The Near and Far-IR SEDs of Spitzer GTO ULIRGs

NASA Astrophysics Data System (ADS)

Marshall, Jason; Armus, Lee; Spoon, Henrik

2008-03-01

Spectra of a sample of 109 ultraluminous infrared galaxies (ULIRGs) have been obtained as part of the Spitzer IRS GTO program, providing a dataset with which to study the underlying obscured energy source(s) (i.e., AGN and/or starburst activity) powering ULIRGs in the local universe, and providing insight into the high-redshift infrared-luminous galaxies responsible for the bulk of the star-formation energy density at z = 2-3. As part of this effort, we have developed the CAFE spectral energy distribution decomposition tool to analyze the UV to sub-mm SEDs of these galaxies (including their IRS spectra). Sufficient photometry for these decompositions exists for approximately half of the GTO ULIRGs. However, we lack crucial data for the other half of the sample in either or both the 2-5 micron gap between the near-IR passbands and the start of the IRS wavelength coverage and the far-IR beyond 100 microns. These spectral regions provide critical constraints on the amount of hot dust near the dust sublimation temperature (indicating the presence of an AGN) and the total luminosity and mass of dust in the galaxy (dominated by the coldest dust emitting at far-IR wavelengths). We therefore propose to obtain IRAC observations in all channels and MIPS observations at 70 and 160 microns for the 37 and 17 GTO ULIRGs lacking data in these wavelength ranges, respectively. Considering its very low cost of 7.3 total hours of observation, the scientific return from this program is enormous: nearly doubling the number of GTO ULIRGs with full spectral coverage, and completing a dataset that is sure to be an invaluable resource well beyond the lifetime of Spitzer.

Structural and magnetic studies of nanocrystalline Y{sub 2}Ir{sub 2}O{sub 7}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dwivedi, Vinod Kumar, E-mail: vinodd@iitk.ac.in; Mukhopadhyay, Soumik

2015-06-24

In this paper, we discuss synthesis of Y{sub 2}Ir{sub 2}O{sub 7} nanoparticles via chemical solution process. Structural analysis shows single cubic phase with Fd-3m space group symmetry. The particle size and distribution were studied by Transmission Electron Microscopy experiments. The average particle size turns out to be 50nm, which is in good agreement with the XRD results. Magnetic characterization shows no evidence of long range ordering even in presence of strong correlations.

Spectral engineering of LaF3:Ce3+ nanoparticles: The role of Ce3+ in surface sites

NASA Astrophysics Data System (ADS)

Jacobsohn, L. G.; Toncelli, A.; Sprinkle, K. B.; Kucera, C. J.; Ballato, J.

2012-04-01

Due to the high surface-to-volume ratio, luminescence centers on the surface have relative dominance in the overall spectral response of nanoparticles. The luminescence of LaF3:Ce3+ nanoparticles was investigated in the spectral and temporal domains with a particular focus on the role of Ce3+ on the surface. These nanoparticles present two luminescence bands at 4.10 eV and 4.37 eV attributed to Ce3+ transitions from the 5d level to the spin-orbit split 4f ground levels 2F5/2 and 2F7/2, in addition to a low-energy band at 3.62 eV that has been attributed to Ce3+ ions residing in perturbed sites. The growth of up to three undoped shells, ca. 0.9 nm thick each, around the core promoted a progressive enhancement of luminescence output, concomitant with an increase in the fluorescence lifetime due to the weakening of energy transfer through multipolar interaction between Ce3+ in the core and quenching defects on the surface. Also, the growth of the first shell led to a decrease in the relative intensity of the low-energy band and a 0.23 eV shift to higher energies. These results were interpreted as being due to the existence of two types of perturbed sites, one on the surface that is eliminated by the growth of the first shell, and another within the volume of the nanoparticle, similar to observations in bulk single crystals. This work demonstrates how surface engineering can affect and control the luminescence behavior of this nanomaterial.

AOTF near-IR spectrometers for study of Lunar and Martian surface composition

NASA Astrophysics Data System (ADS)

Korablev, O.; Kiselev, A.; Vyazovetskiy, N.; Fedorova, A.; Evdokimova, N.; Stepanov, A.; Titov, A.; Kalinnikov, Y.; Kuzmin, R. O.; Bazilevsky, A. T.; Bondarenko, A.; Moiseev, P.

2013-09-01

The series of the AOTF near-IR spectrometers is developed in Moscow Space Research Institute for study of Lunar and Martian surface composition in the vicinity of a lander or a rover. Lunar Infrared Spectrometer (LIS) is an experiment onboard Luna-Glob (launch in 2015) and Luna-Resurs (launch in 2017) Russian surface missions. The LIS is mounted on the mechanic arm of landing module in the field of view (45°) of stereo TV camera. Infrared Spectrometer for ExoMars (ISEM) is an experiment onboard ExoMars (launch in 2018) ESARoscosmos rover. The ISEM instrument is mounted on the rover's mast together with High Resolution camera (HRC). Spectrometers will provide measurements of selected surface area in the spectral range of 1.15-3.3 μm. The electrically commanded acousto-optic filter scans sequentially at a desired sampling, with random access, over the entire spectral range.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization

NASA Astrophysics Data System (ADS)

Gopi, D.; Kanimozhi, K.; Bhuvaneshwari, N.; Indira, J.; Kavitha, L.

2014-01-01

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy (1H NMR) and carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications.

Third-generation intelligent IR focal plane arrays

NASA Astrophysics Data System (ADS)

Caulfield, H. John; Jack, Michael D.; Pettijohn, Kevin L.; Schlesselmann, John D.; Norworth, Joe

1998-03-01

SBRC is at the forefront of industry in developing IR focal plane arrays including multi-spectral technology and '3rd generation' functions that mimic the human eye. 3rd generation devices conduct advanced processing on or near the FPA that serve to reduce bandwidth while performing needed functions such as automatic target recognition, uniformity correction and dynamic range enhancement. These devices represent a solution for processing the exorbitantly high bandwidth coming off large area FPAs without sacrificing systems sensitivity. SBRC's two-color approach leverages the company's HgCdTe technology to provide simultaneous multiband coverage, from short through long wave IR, with near theoretical performance. IR systems that are sensitive to different spectral bands achieve enhanced capabilities for target identification and advanced discrimination. This paper will provide a summary of the issues, the technology and the benefits of SBRC's third generation smart and two-color FPAs.

Characterization and carboplatin loaded chitosan nanoparticles for the chemotherapy against breast cancer in vitro studies.

PubMed

Khan, Md Asad; Zafaryab, Md; Mehdi, Syed Hassan; Quadri, Javed; Rizvi, M Moshahid A

2017-04-01

Aim of the studies to synthesized chitosan nanoparticles by an ionic interaction procedure. The nanoparticles were characterized by physicochemical methods like, DLS, TEM, Surface potential measurements, FT-IR and DSC. The average particle size of chitosan and carboplatin nanoparticles was found to be 277.25±11.37nm and 289.30±8.15nm and zeta potential was found to be 31±3.14mV and 33±2.15mV respectively with low polydispersity index. The maximum entrapment of carboplatin in nanoparticles was a spherical shape with a positive charge. The maximum encapsulation and loading efficiencies of carboplatin (5mg/ml) were obtained to be 58.43% and 13.27% respectively. The nanocarboplatin was better blood compatibility as compared to chitosan nanoparticles. Finally, the cytotoxic effects of the carboplatin loaded chitosan nanoparticles were tested in-vitro against breast cancer (MCF-7) cell lines. Our studies showed that the chitosan nanoparticles could be used as a promising candidate for drug delivery for the therapeutic treatment of breast cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Extending laser plasma accelerators into the mid-IR spectral domain with a next-generation ultra-fast CO 2 laser

DOE PAGES

Pogorelsky, I. V.; Babzien, M.; Ben-Zvi, I.; ...

2016-01-20

Here we discuss how expanding the scope of relativistic plasma research to wavelengths longer than λ/≈0.8₋1.1μm covered by conventional mode-locked solid-state lasers would offer attractive opportunities due to the quadratic scaling of the ponderomotive electron energy and critical plasma density with λ. Answering this quest, a next-generation mid-IR laser project is being advanced at the BNL ATF as a part of the user facility upgrade. We discuss the technical approach to this conceptually new 100 TW, 100 fs, λ=9₋11 μm CO 2 laser BESTIA (Brookhaven Experimental Supra-Terawatt Infrared at ATF) that encompasses several innovations applied for the first time tomore » molecular gas lasers. BESTIA will enable new regimes of laser plasma accelerators. One for example is shock-wave ion acceleration from gas jets. We review ongoing efforts to achieve stable, monoenergetic proton acceleration by dynamically shaping the plasma density profile from a hydrogen gas target with laser-produced blast waves. At its full power, 100 TW BESTIA promises to achieve proton beams at energy exceeding 200 MeV. In addition to ion acceleration in over-critical plasma, the ultra-intense mid-IR laser BESTIA will open new opportunities in driving wakefields in tenuous plasmas, expanding the landscape of Laser Wake Field Accelerator (LWFA) studies into unexplored long-wavelength spectral domain. Simple wavelength scaling suggests that a 100-TW CO2 laser beam will be capable to efficiently generate plasma “bubbles” thousand times bigger in volume compared to a near-IR solid state laser of an equivalent power. Combined with a femtosecond electron linac available at the ATF, this wavelength scaling will facilitate study of external seeding and staging of LWFA.« less

NASA's Far-IR/Submillimeter Roadmap Missions SAFIR and SPECS

NASA Technical Reports Server (NTRS)

Leisawitz, David

2003-01-01

The far-IR is rich with information about star, disk and planet formation because protostars emit predominantly in this spectral range, and the radiation can escape from the inherently dusty stellar birth sites. Spectral lines contain particularly valuable information about the cooling, collapse, and chemistry of molecular cloud cores and protostars. However, the interpretation of line intensities and profiles is model-dependent; ultimately, high angular resolution is needed to break model degeneracy and definitively characterize the source. Processes occurring on scales smaller than 10,000 AU (72 arcsec at 140 pc, where the nearest protostellar objects are found) likely affect the stellar initial mass function and determine the product of cloud collapse (Binary star or planetary system? How many planets, and what kind will they be?) The next-generation far-IR observatories SIRTF, SOFIA, and Herschel will revolutionize star formation studies and leave the community yearning for telescopes that operate in this spectral region but provide many orders of magnitude better angular resolution. NASA's space science roadmap includes the JWST-scale Single Aperture Far-IR (SAFIR) telescope and the 1 km maximum baseline far-IR interferometer, SPECS (the Submillimeter Probe of the Evolution of Cosmic Structure). I will give the scientific motivation for these missions, describe mission concepts and telescope measurement capabilities, and compare these capabilities with those of the next-generation IR telescopes and with the complementary JWST and ALMA. I will also describe the Space Infrared Interferometric Telescope (SPIRIT), a science and technology pathfinder for SPECS, which could be ready to launch in about a decade. At 100 microns, SAFIR will provide 2.5 arcsec resolution (10 times better than SIRTF), SPIRIT will provide 0.25 arcsec resolution, and SPECS will provide 10 milli-arcsec resolution, which is comparable to that of the Hubble Space Telescope.

Toward the characterization of biological toxins using field-based FT-IR spectroscopic instrumentation

NASA Astrophysics Data System (ADS)

Schiering, David W.; Walton, Robert B.; Brown, Christopher W.; Norman, Mark L.; Brewer, Joseph; Scott, James

2004-12-01

IR spectroscopy is a broadly applicable technique for the identification of covalent materials. Recent advances in instrumentation have made Fourier Transform infrared (FT-IR) spectroscopy available for field characterization of suspect materials. Presently, this instrumentation is broadly deployed and used for the identification of potential chemical hazards. This discussion concerns work towards expanding the analytical utility of field-based FT-IR spectrometry in the characterization of biological threats. Two classes of materials were studied: biologically produced chemical toxins which were non-peptide in nature and peptide toxin. The IR spectroscopic identification of aflatoxin-B1, trichothecene T2 mycotoxin, and strychnine was evaluated using the approach of spectral searching against large libraries of materials. For pure components, the IR method discriminated the above toxins at better than the 99% confidence level. The ability to identify non-peptide toxins in mixtures was also evaluated using a "spectral stripping" search approach. For the mixtures evaluated, this method was able to identify the mixture components from ca. 32K spectral library entries. Castor bean extract containing ricin was used as a representative peptide toxin. Due to similarity in protein spectra, a SIMCA pattern recognition methodology was evaluated for classifying peptide toxins. In addition to castor bean extract the method was validated using bovine serum albumin and myoglobin as simulants. The SIMCA approach was successful in correctly classifying these samples at the 95% confidence level.

Application of organic IR788-loaded semi-interpenetrating network dyes for photoacoustic imaging

NASA Astrophysics Data System (ADS)

Phuc Nguyen, Van; Kim, Hyejin; Kang, Mingyeong; Kwak, Minseok; Kang, Hyun Wook

2017-07-01

In this study, we present the feasibility of a biocompatible Lumogen® IR788-loaded polymeric nanoparticle (NP) as a novel photoabsorbing agent for photoacoustic (PA) imaging. The NP was fabricated through a semi-interpenetrating network (sIPN) within the core of F127 resulting in IR788-sIPN formation. To evaluate the PA sensitivity of the material, tubing phantoms were injected with various concentrations of IR788-sIPN, and H1975 lung-tumor-bearing mice were intratumorally injected with IR788-sIPN. Compared with the background, the PA contrast was enhanced up to 80 and 40% in the phantom and in vivo experiments, respectively. IR788-sIPN can be a feasible IR-absorbing material for early cancer detection.

Study of BSA protein adsorption/release on hydroxyapatite nanoparticles

NASA Astrophysics Data System (ADS)

Swain, Sanjaya Kumar; Sarkar, Debasish

2013-12-01

Three different spherical, rod and fibrous morphologies of hydroxyapatite (HA) nanoparticles have been prepared through control over the processing parameters like temperature, pH and Ca:P ratio. Protein adsorption/release with respect to HA nanoparticle morphologies are investigated using model protein bovine serum albumin (BSA). BSA adsorption on HA nanoparticles follows Langmuir adsorption isotherm. Thermal analysis and FT-IR spectrum confirms the BSA adhesion and retention of their secondary structure. High surface area with high Ca:P ratio nanorod adsorbs relatively more amount (28 mg BSA/gm of nanorod HA) of BSA within 48 h in comparison with counterpart fibroid and spherical morphologies. Slow and steady BSA release (75 wt% of adsorbed BSA in 96 h) from nanorod HA is found as futuristic drug delivery media.

Airborne pipeline leak detection: UV or IR?

NASA Astrophysics Data System (ADS)

Babin, François; Gravel, Jean-François; Allard, Martin

2016-05-01

This paper presents a study of different approaches to the measurement of the above ground vapor plume created by the spill caused by a small 0.1 l/min (or less) leak in an underground liquid petroleum pipeline. The scenarios are those for the measurement from an airborne platform. The usual approach is that of IR absorption, but in the case of liquid petroleum products, there are drawbacks that will be discussed, especially when using alkanes to detect a leak. The optical measurements studied include UV enhanced Raman lidar, UV fluorescence lidar and IR absorption path integrated lidars. The breadboards used for testing the different approaches will be described along with the set-ups for leak simulation. Although IR absorption would intuitively be the most sensitive, it is shown that UV-Raman could be an alternative. When using the very broad alkane signature in the IR, the varying ground spectral reflectance are a problem. It is also determined that integrated path measurements are preferred, the UV enhanced Raman measurements showing that the vapor plume stays very close to the ground.

Spectral properties of nanocomposites based on fluorine-containing polymer and gold nanoparticles

NASA Astrophysics Data System (ADS)

Barmina, E. V.; Mel’nik, N. N.; Rakov, I. I.; Ivanov, V. E.; Simakin, A. V.; Gudkov, S. V.; Shafeev, G. A.

2018-04-01

The optical properties of nanocomposites of gold nanoparticles and fluorine-containing polymer have been studied. Gold nanoparticles were obtained by laser ablation of gold or terbium targets in organic solvents. The thus formed colloidal solutions were used to prepare nanocomposites of gold nanoparticles in polymer matrices of transparent and colorless fluorine-containing polymer. The polymer matrix is found to promote aggregation of nanoparticles of metal under study into elongated chains. In turn, metal nanoparticles influence on the polymer matrix. Gold nanoparticles amplify the Raman signal of the polymer matrix. In addition, the Raman spectra of nanocomposites indicate aggregation of disordered carbon around the nanoparticles obtained by laser ablation in organic solvents.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization.

PubMed

Gopi, D; Kanimozhi, K; Bhuvaneshwari, N; Indira, J; Kavitha, L

2014-01-24

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy ((1)H NMR) and carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

[IR study on a series of tungsten clusters].

PubMed

Yu, R; Chen, J; Lu, S

2000-10-01

In this paper, the IR study on a series of tungsten clusters which contain a [W2S4]2+ or [W2MM'S4]4+ (M,M'=Cu,Ag) core is reported. According to the results of X-ray structural analysis and the IR spectra of the clusters, some characteristic IR absorptions of the clusters were assigned. The study of IR spectra of these clusters shows that the variation of structure can reflect on the IR spectra significantly.

Magnesium Nanoparticle Plasmonics.

PubMed

Biggins, John S; Yazdi, Sadegh; Ringe, Emilie

2018-06-13

Nanoparticles of some metals (Cu/Ag/Au) sustain oscillations of their electron cloud called localized surface plasmon resonances (LSPRs). These resonances can occur at optical frequencies and be driven by light, generating enhanced electric fields and spectacular photon scattering. However, current plasmonic metals are rare, expensive, and have a limited resonant frequency range. Recently, much attention has been focused on earth-abundant Al, but Al nanoparticles cannot resonate in the IR. The earth-abundant Mg nanoparticles reported here surmount this limitation. A colloidal synthesis forms hexagonal nanoplates, reflecting Mg's simple hexagonal lattice. The NPs form a thin self-limiting oxide layer that renders them stable suspended in 2-propanol solution for months and dry in air for at least two week. They sustain LSPRs observable in the far-field by optical scattering spectroscopy. Electron energy loss spectroscopy experiments and simulations reveal multiple size-dependent resonances with energies across the UV, visible, and IR. The symmetry of the modes and their interaction with the underlying substrate are studied using numerical methods. Colloidally synthesized Mg thus offers a route to inexpensive, stable nanoparticles with novel shapes and resonances spanning the entire UV-vis-NIR spectrum, making them a flexible addition to the nanoplasmonics toolbox.

Differentiation of aflatoxigenic and non-aflatoxigenic strains of Aspergilli by FT-IR spectroscopy.

PubMed

Atkinson, Curtis; Pechanova, Olga; Sparks, Darrell L; Brown, Ashli; Rodriguez, Jose M

2014-01-01

Fourier transform infrared spectroscopy (FT-IR) is a well-established and widely accepted methodology to identify and differentiate diverse microbial species. In this study, FT-IR was used to differentiate 20 strains of ubiquitous and agronomically important phytopathogens of Aspergillus flavus and Aspergillus parasiticus. By analyzing their spectral profiles via principal component and cluster analysis, differentiation was achieved between the aflatoxin-producing and nonproducing strains of both fungal species. This study thus indicates that FT-IR coupled to multivariate statistics can rapidly differentiate strains of Aspergilli based on their toxigenicity.

Interaction of amino acid-functionalized silver nanoparticles and Candida albicans polymorphs: A deep-UV fluorescence imaging study.

PubMed

Dojčilović, Radovan; Pajović, Jelena D; Božanić, Dušan K; Bogdanović, Una; Vodnik, Vesna V; Dimitrijević-Branković, Suzana; Miljković, Miona G; Kaščaková, Slavka; Réfrégiers, Matthieu; Djoković, Vladimir

2017-07-01

The interaction of the tryptophan functionalized Ag nanoparticles and live Candida albicans cells was studied by synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging at the DISCO beamline of Synchrotron SOLEIL. DUV imaging showed that incubation of the fungus with functionalized nanoparticles results in significant increase in the fluorescence signal. The analysis of the images revealed that the interaction of the nanoparticles with (pseudo)hyphae polymorphs of the diploid fungus was less pronounced than in the case of yeast cells or budding spores. The changes in the intensity of the fluorescence signals of the cells after incubation were followed in [327-353nm] and [370-410nm] spectral ranges that correspond to the fluorescence of tryptophan in non-polar and polar environment, respectively. As a consequence of the environmental sensitivity of the silver-tryptophan fluorescent nanoprobe, we were able to determine the possible accumulation sites of the nanoparticles. The analysis of the intensity decay kinetics showed that the photobleaching effects were more pronounced in the case of the functionalized nanoparticle treated cells. The results of time-integrated emission in the mentioned spectral ranges suggested that the nanoparticles penetrate the cells, but that the majority of the nanoparticles attach to the cells' surfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Advances in handheld FT-IR instrumentation

NASA Astrophysics Data System (ADS)

Arnó, Josep; Cardillo, Len; Judge, Kevin; Frayer, Maxim; Frunzi, Michael; Hetherington, Paul; Levy, Dustin; Oberndorfer, Kyle; Perec, Walter; Sauer, Terry; Stein, John; Zuidema, Eric

2012-06-01

FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenges of ConOps (Concepts of Operation) in emergency response and military field applications require a significant redesign of the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, quick and easy interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the advances resulting from a project designed to overcome the challenges associated with miniaturizing FT-IR instruments. The project team developed a disturbance-corrected permanently aligned cube corner interferometer for improved robustness and optimized opto-mechanical design to maximize optical throughput and signal-to-noise ratios. Thermal management and heat flow were thoroughly modeled and studied to isolate sensitive components from heat sources and provide the widest temperature operation range. Similarly, extensive research on mechanical designs and compensation techniques to protect against shock and vibration will be discussed. A user interface was carefully created for military and emergency response applications to provide actionable information in a visual, intuitive format. Similar to the HazMatID family of products, state-of-the-art algorithms were used to quickly identify the chemical composition of complex samples based on the spectral information. This article includes an overview of the design considerations, tests results, and performance validation of the mechanical ruggedness, spectral, and thermal performance.

Microstructures as IR-sensors with Staphylococcus aureus bacteria

NASA Astrophysics Data System (ADS)

Baikova, T. V.; Danilov, P. A.; Gonchukov, S. A.; Yermachenko, V. M.; Ionin, A. A.; Khmelnitskii, R. A.; Kudryashov, S. I.; Nguyen, T. T. H.; Rudenko, A. A.; Saraeva, I. N.; Svistunova, T. S.; Zayarny, D. A.

2017-09-01

Using a micro-hole grating in a supported silver film as a laser-fabricated novel optical platform for surface-enhanced IR absoprtion/reflection spectroscopy, characteristic absorption bands of Staphylococcus aureus, especially - its buried carotenoid fragments - were detected in FT-IR spectra with 10-fold analytical enhancement, paving the way to spectral express-identification of the pathogenic microorganisms.

Application of FT-IR spectroscopy on breast cancer serum analysis

NASA Astrophysics Data System (ADS)

Elmi, Fatemeh; Movaghar, Afshin Fayyaz; Elmi, Maryam Mitra; Alinezhad, Heshmatollah; Nikbakhsh, Novin

2017-12-01

Breast cancer is regarded as the most malignant tumor among women throughout the world. Therefore, early detection and proper diagnostic methods have been known to help save women's lives. Fourier Transform Infrared (FT-IR) spectroscopy, coupled with PCA-LDA analysis, is a new technique to investigate the characteristics of serum in breast cancer. In this study, 43 breast cancer and 43 healthy serum samples were collected, and the FT-IR spectra were recorded for each one. Then, PCA analysis and linear discriminant analysis (LDA) were used to analyze the spectral data. The results showed that there were differences between the spectra of the two groups. Discriminating wavenumbers were associated with several spectral differences over the 950-1200 cm- 1(sugar), 1190-1350 cm- 1 (collagen), 1475-1710 cm- 1 (protein), 1710-1760 cm- 1 (ester), 2800-3000 cm- 1 (stretching motions of -CH2 & -CH3), and 3090-3700 cm- 1 (NH stretching) regions. PCA-LDA performance on serum IR could recognize changes between the control and the breast cancer cases. The diagnostic accuracy, sensitivity, and specificity of PCA-LDA analysis for 3000-3600 cm- 1 (NH stretching) were found to be 83%, 84%, 74% for the control and 80%, 76%, 72% for the breast cancer cases, respectively. The results showed that the major spectral differences between the two groups were related to the differences in protein conformation in serum samples. It can be concluded that FT-IR spectroscopy, together with multivariate data analysis, is able to discriminate between breast cancer and healthy serum samples.

Directionality of Spectral and Polarimetric Measurements of Soils

NASA Astrophysics Data System (ADS)

Furey, J.; Zahniser, S. R.; Morgan, C.; Lewis, M. G.

2017-12-01

Spectral and polarimetric instruments mounted on a goniometer in a laboratory setting measured directionality effects for discriminating disturbed from undisturbed soils at varied illumination and look angles. Over 8000 custom polarimetric images, using rotating linear polarizers, were acquired at 63 goniometer positions in the Visible (Vis), Near InfraRed (NIR), Short Wave IR (SWIR), and Long Wave IR (LWIR) spectral bands, as well as a hyperspectral imager in the Vis through NIR (Resonon Pika), and a nonimaging hyperspectral instrument (ASD Fieldspec). The soils had been sampled from earlier field studies in the Global Undisturbed/Disturbed Earth (GUIDE) program, and the soil surfaces were prepared in disturbed and undisturbed states for laboratory measurement. No one spectral range was most effective at discriminating at all azimuth and elevation angles for any soil, but polarimetric SWIR was the most often effective. Azimuthal spectral variations did not provide statistically significant discrimination in themselves. Other preliminary findings are that polarimetry is key to understanding azimuthal effects and that nadir spectra are the least predictive.

Study of polarized IR spectra of the hydrogen bond system in crystals of styrylacetic acid

NASA Astrophysics Data System (ADS)

Flakus, Henryk T.; Jabłońska, Magdalena; Jones, Peter G.

2006-10-01

We have investigated the polarized IR spectra of the hydrogen bond system in crystals of trans-styrylacetic acid C 6H 5sbnd CH dbnd CH sbnd CH 2sbnd COOH, and also in crystals of the following three deuterium isotopomers of the compound: C 6H 5sbnd CH dbnd CH sbnd CH 2sbnd COOD, C 6H 5sbnd CH dbnd CH sbnd CD 2sbnd COOH and C 6H 5sbnd CH dbnd CH sbnd CD 2sbnd COOD. The spectra were measured at room temperature and at 77 K by a transmission method. The spectral studies were preceded by determination of the X-ray crystal structure. Theoretical analysis of the results concerned linear dichroic effects, the H/D isotopic and temperature effects, observed in the solid-state IR spectra of the hydrogen and of the deuterium bond, at the frequency ranges of the νO sbnd H and the νO sbnd D bands, respectively. Basic spectral properties of the crystals can be interpreted satisfactorily in terms of the " strong-coupling" theory, when based on a hydrogen bond dimer model. This model sufficiently explained not only a two-branch structure of the νO sbnd H and the νO sbnd D bands, and temperature-induced evolution of the crystalline spectra, but also the linear dichroic effects observed in the band frequency ranges. A vibronic mechanism was analyzed, responsible for promotion of the symmetry-forbidden transition in the IR for the totally symmetric proton stretching vibrations in centrosymmetric hydrogen bond dimers. It was found to be of minor importance, when compared with analogous spectral properties of arylcarboxylic acid, or of cinnamic acid crystals. These effects were ascribed to a substantial weakening of electronic couplings between the hydrogen bonds of the associated carboxyl groups and the styryl radicals, associated with the separation of these groups in styrylacetic acid molecules by methylene groups in the molecules.

Biogenic silver nanoparticles using Rhinacanthus nasutus leaf extract: synthesis, spectral analysis, and antimicrobial studies

PubMed Central

Pasupuleti, Visweswara Rao; Prasad, TNVKV; Shiekh, Rayees Ahmad; Balam, Satheesh Krishna; Narasimhulu, Ganapathi; Reddy, Cirandur Suresh; Rahman, Ismail Ab; Gan, Siew Hua

2013-01-01

Nanotechnology is gaining momentum due to its ability to transform metals into nanoparticles. The synthesis, characterization, and applications of biologically synthesized nanomaterials have become an important branch of nanotechnology. Plant extracts are a cost-effective, ecologically friendly, and efficient alternative for the large-scale synthesis of nanoparticles. In this study, silver nanoparticles (AgNps) were synthesized using Rhinacanthus nasutus leaf extract. After exposing the silver ions to the leaf extract, the rapid reduction of silver ions led to the formation of AgNps in solution. The synthesis was confirmed by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. The in vitro antimicrobial activity of the AgNps synthesized using R. nasutus leaf extract was investigated against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli, Aspergillus niger, and Aspergillus flavus using a disc diffusion method. The AgNps showed potential activity against all of the bacterial strains and fungal colonies, indicating that R. nasutus has the potential to be used in the development of value-added products in the biomedical and nanotechnology-based industries. PMID:24039419

Biogenic silver nanoparticles using Rhinacanthus nasutus leaf extract: synthesis, spectral analysis, and antimicrobial studies.

PubMed

Pasupuleti, Visweswara Rao; Prasad, T N V; Shiekh, Rayees Ahmad; Balam, Satheesh Krishna; Narasimhulu, Ganapathi; Reddy, Cirandur Suresh; Ab Rahman, Ismail; Gan, Siew Hua

2013-01-01

Nanotechnology is gaining momentum due to its ability to transform metals into nanoparticles. The synthesis, characterization, and applications of biologically synthesized nanomaterials have become an important branch of nanotechnology. Plant extracts are a cost-effective, ecologically friendly, and efficient alternative for the large-scale synthesis of nanoparticles. In this study, silver nanoparticles (AgNps) were synthesized using Rhinacanthus nasutus leaf extract. After exposing the silver ions to the leaf extract, the rapid reduction of silver ions led to the formation of AgNps in solution. The synthesis was confirmed by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. The in vitro antimicrobial activity of the AgNps synthesized using R. nasutus leaf extract was investigated against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli, Aspergillus niger, and Aspergillus flavus using a disc diffusion method. The AgNps showed potential activity against all of the bacterial strains and fungal colonies, indicating that R. nasutus has the potential to be used in the development of value-added products in the biomedical and nanotechnology-based industries.

Multi-spectral imaging with infrared sensitive organic light emitting diode

PubMed Central

Kim, Do Young; Lai, Tzung-Han; Lee, Jae Woong; Manders, Jesse R.; So, Franky

2014-01-01

Commercially available near-infrared (IR) imagers are fabricated by integrating expensive epitaxial grown III-V compound semiconductor sensors with Si-based readout integrated circuits (ROIC) by indium bump bonding which significantly increases the fabrication costs of these image sensors. Furthermore, these typical III-V compound semiconductors are not sensitive to the visible region and thus cannot be used for multi-spectral (visible to near-IR) sensing. Here, a low cost infrared (IR) imaging camera is demonstrated with a commercially available digital single-lens reflex (DSLR) camera and an IR sensitive organic light emitting diode (IR-OLED). With an IR-OLED, IR images at a wavelength of 1.2 µm are directly converted to visible images which are then recorded in a Si-CMOS DSLR camera. This multi-spectral imaging system is capable of capturing images at wavelengths in the near-infrared as well as visible regions. PMID:25091589

Multi-spectral imaging with infrared sensitive organic light emitting diode

NASA Astrophysics Data System (ADS)

Kim, Do Young; Lai, Tzung-Han; Lee, Jae Woong; Manders, Jesse R.; So, Franky

2014-08-01

Commercially available near-infrared (IR) imagers are fabricated by integrating expensive epitaxial grown III-V compound semiconductor sensors with Si-based readout integrated circuits (ROIC) by indium bump bonding which significantly increases the fabrication costs of these image sensors. Furthermore, these typical III-V compound semiconductors are not sensitive to the visible region and thus cannot be used for multi-spectral (visible to near-IR) sensing. Here, a low cost infrared (IR) imaging camera is demonstrated with a commercially available digital single-lens reflex (DSLR) camera and an IR sensitive organic light emitting diode (IR-OLED). With an IR-OLED, IR images at a wavelength of 1.2 µm are directly converted to visible images which are then recorded in a Si-CMOS DSLR camera. This multi-spectral imaging system is capable of capturing images at wavelengths in the near-infrared as well as visible regions.

Photochemistry of Fe:H2O Adducts in Argon Matrixes: A Combined Experimental and Theoretical Study in the Mid-IR and UV-Visible Regions.

PubMed

Deguin, Vincent; Mascetti, Joëlle; Simon, Aude; Ben Amor, Nadia; Aupetit, Christian; Latournerie, Sandra; Noble, Jennifer A

2018-01-18

The photochemistry of Fe:H 2 O adducts is of interest in fields as diverse as catalysis and astrochemistry. Industrially, iron can be used as a catalyst to convert H 2 O to H 2 , whereas in the interstellar medium it may be an important component of dust grains, influencing the chemistry on their icy surfaces. This study consisted of the deposition and spectral characterization of binary systems of atomic iron with H 2 O in cryogenic argon matrixes. In this way, we were able to obtain information about the interaction of the two species; we observed the formation of adducts of iron monomers and dimers with water molecules in the mid-IR and UV-visible spectral domains. Upon irradiation with a UV radiation source, the iron species were inserted into the water molecules to form HFeOH and HFe 2 OH, leading in some cases to the formation of FeO possibly accompanied by the production of H 2 . DFT and correlated multireference wave function calculations confirmed our attributions. This combination of IR and UV-visible spectroscopy with theoretical calculations allowed us to determine, for the first time, the spectral characteristics of iron adducts and their photoproducts in the UV-visible and in the OH stretching region of the mid-IR domain.

An improved synthesis, spectroscopic (FT-IR, NMR) study and DFT computational analysis (IR, NMR, UV-Vis, MEP diagrams, NBO, NLO, FMO) of the 1,5-methanoazocino[4,3-b]indole core structure

NASA Astrophysics Data System (ADS)

Uludağ, Nesimi; Serdaroğlu, Goncagül

2018-03-01

This study examines the synthesis of azocino[4,3-b]indole structure, which constitutes the tetracyclic framework of uleine, dasycarpidoneand tubifolidineas well as ABDE substructure of the strychnosalkaloid family. It has been synthesized by Fischer indolization of 2 and through the cylization of 4 by 2,3-dichlor-5-6-dicyanobenzoquinone (DDQ). 1H and 1C NMR chemical shifts have been predicted with GIAO approach and the calculated chemical shifts show very good agreement with observed shifts. FT-IR spectroscopy is important for the analysis of functional groups of synthesized compounds and we also supported FT-IR vibrational analysis with computational IR analysis. The vibrational spectral analysis was performed at B3LYP level of the theory in both the gas and the water phases and it was compared with the observed IR values for the important functional groups. The DFT calculations have been conducted to determine the most stable structure of the 1,2,3,4,5,6,7-Hexahydro-1,5-methanoazocino [4,3-b] indole (5). The Frontier Molecular Orbital Analysis, quantum chemical parameters, physicochemical properties have been predicted by using the same theory of level in both gas phase and the water phase, at 631 + g** and 6311++g** basis sets. TD- DFT calculations have been performed to predict the UV- Vis spectral analysis for this synthesized molecule. The Natural Bond Orbital (NBO) analysis have been performed at B3LYP level of theory to elucidate the intra-molecular interactions such as electron delocalization and conjugative interactions. NLO calculations were conducted to obtain the electric dipole moment and polarizability of the title compound.

Upconversion of the mid-IR pulses to the near-IR in LiGaS2

NASA Astrophysics Data System (ADS)

Kato, Kiyoshi; Umemura, Nobuhiro; Okamoto, Takuya; Petrov, Valentin

2018-02-01

This paper reports on the phase-matching properties of LiGaS2 for upconverting a Nd:YAG laser-pumped KTP and AgGaS2 optical parametric oscillator (OPO) at mid-IR to the near-IR by mixing with its pump source together with the new Sellmeier equations that provide a good reproduction of the present experimental results as well as the published data points of second-harmonic generation (SHG) and sum-frequency generation (SFG) of a CO2 laser, a Ti:Al2O3 laser-pumped optical parametric amplifier (OPA), and a Nd:YAG laser-pumped OPO in the mid-IR. This index formula gives the important information that group velocity mismatch (GVM) (Δsp = 1/υs - 1/υp) of LiGaS2 in the 4 - 11 μm range is 12 27 fs/mm lower than that of the widely used LiInS2, which makes it ideal for the upconversion of the mid-IR femtosecond pulses having large spectral bandwidths to the near-IR.

Prophylactic Treatment with Cerium Oxide Nanoparticles Attenuate Hepatic Ischemia Reperfusion Injury in Sprague Dawley Rats.

PubMed

Manne, Nandini D P K; Arvapalli, Ravikumar; Graffeo, Vincent A; Bandarupalli, Venkata V K; Shokuhfar, Tolou; Patel, Sweetu; Rice, Kevin M; Ginjupalli, Gautam Kumar; Blough, Eric R

2017-01-01

Hepatic ischemia reperfusion is one the main causes for graft failure following transplantation. Although, the molecular events that lead to hepatic failure following ischemia reperfusion (IR) are diverse and complex, previous studies have shown that excessive formation of reactive oxygen species (ROS) are responsible for hepatic IR injury. Cerium oxide (CeO2) nanoparticles have been previously shown to act as an anti-oxidant and anti-inflammatory agent. Here, we evaluated the protective effects of CeO2 nanoparticles on hepatic ischemia reperfusion injury. Male Sprague Dawley rats were randomly assigned to one of the four groups: Control, CeO2 nanoparticle only, hepatic ischemia reperfusion (IR) group and hepatic ischemia reperfusion (IR) plus CeO2 nanoparticle group (IR+ CeO2). Partial warm hepatic ischemia was induced in left lateral and median lobes for 1h, followed by 6h of reperfusion. Animals were sacrificed after 6h of reperfusion and blood and tissue samples were collected and processed for various biochemical experiments. Prophylactic treatment with CeO2 nanoparticles (0.5mg/kg i.v (IR+CeO2 group)) 1 hour prior to hepatic ischemia and subsequent reperfusion injury lead to a decrease in serum levels of alanine aminotransaminase and lactate dehydrogenase at 6 hours after reperfusion. These changes were accompanied by significant decrease in hepatocyte necrosis along with reduction in several serum inflammatory markers such as macrophage derived chemokine, macrophage inflammatory protein-2, KC/GRO, myoglobin and plasminogen activator inhibitor-1. However, immunoblotting demonstrated no significant changes in the levels of apoptosis related protein markers such as bax, bcl2 and caspase 3 in IR and IR+ CeO2 groups at 6 hours suggesting necrosis as the main pathway for hepatocyte death. Taken together, these data suggest that CeO2 nanoparticles attenuate IR induced cell death and can be used as a prophylactic agent to prevent hepatic injury associated with graft

Group 12 dithiocarbamate complexes: Synthesis, spectral studies and their use as precursors for metal sulfides nanoparticles and nanocomposites

NASA Astrophysics Data System (ADS)

Ajibade, Peter A.; Ejelonu, Benjamin C.

2013-09-01

Zn(II), Cd(II) and Hg(II) dithiocarbamate complexes have been synthesized and characterized by elemental analysis, thermogravimetric analysis, UV-Vis, FTIR, 1H- and 13C NMR spectroscopy. The complexes were thermolysed at 180 °C and used as single molecule precursors for the synthesis of HDA capped ZnS, CdS and HgS nanoparticles and polymethylmethacrylate (PMMA) nanocomposites. The optical and structural properties of the nanoparticles and nanocomposites were studied by UV-Vis, PL, XRD and SEM. The crystallites sizes of the nanoparticles varied between 3.03 and 23.45 nm. SEM and EDX analyses of the nanocomposites confirmed the presence of the nanoparticles in the polymer matrix.

Combining spectral material properties in the infrared and the visible spectral range for qualification and nondestructive evaluation of components

NASA Astrophysics Data System (ADS)

Eisler, K.; Goldammer, M.; Rothenfusser, M.; Arnold, W.; Homma, C.

2012-05-01

The spectral selective thermography with infrared filters can be used to determine or to distinguish materials such as contaminations on a metallic component. With additional visual information, the indications by the IR signal can be selectively accentuated or suppressed for easier evaluation of passive and active thermography measurements. For flash thermography the detected IR signal between 3.4 and 5.1 μm is analyzed with regard to the spectral material information. The presented hybrid camera uses beam overlapping to obtain combined images of both in the infrared and the visual range.

Compositional maps and VIS-IR spectral indicators of Vesta's surface retrieved from VIR hyperspectral data

NASA Astrophysics Data System (ADS)

Filacchione, G.; Ammannito, E.; Coradini, A.; De sanctis, M.; Capaccioni, F.; Tosi, F.; Capria, M. T.; Palomba, E.; Magni, G.; Fonte, S.; Carraro, F.; McSween, H. Y.; Raymond, C. A.; Russell, C. T.; McCord, T. B.; Pieters, C. M.; Sunshine, J. M.; Titus, T. N.; Combe, J.; Dawn Science Team

2011-12-01

In July 2011, VIR-MS, Visible and Infrared Mapping Spectrometer, aboard the Dawn mission has started a systematic exploration of minor planet Vesta from a 5000 km polar orbit (approach phase). Since then, the instrument has returned hyperspectral cubes in the 0.25-5 μm range with both global and regional views of Vesta's surface. Thanks to the high spatial (250 μrad IFOV, corresponding to a 1.25 km/pixel scale from a 5000 km altitude orbit) and spectral resolution (2 nm/band between 0.25-1 μm and 10 nm/band in the 1-5 μm range), VIR has the capabilities to infer the mineralogical composition of the crust, to discriminate among the very different compositional units, to map their distribution across the surface and to correlate composition with geological features. Since the amount of information provided by each VIR pixel is very large (864 channels), we have developed the VIR Mineralogical Tool (VMT) with the scope of measuring some specific spectral quantities which are tuned to identify the different howarditic, eucritic and diogenitic (HED) components of the crust, thanks to laboratory measurements and ground-based observations of HED meteorites. Continuum levels, VIS-IR band ratios, band I-II properties (center, depth, width, asymmetry), spectral slopes and their mutual correlations are among the principal spectral indicators used to infer the crustal basaltic composition. As a general rule for basaltic materials: 1) the ratio of band I/II areas gives the Band Area Ratio (BAR) which is function of the relative abundance of olivine/orthopyroxene; 2) the value of the I Vs. II band depths is an indicator of the composition, allowing to discriminate among HEDs. An alternative method is based on the correlation between band I width and 0.7-1.3 μm slope or the band I depth Vs. the 0.67-0.95 μm slope; 3) the amount of Fs, Wo and Mg is retrieved from the band I center and band II minima wavelengths; 4) the alteration of the surface, induced by weathering

New Ir Bis-Carbonyl Precursor for Water Oxidation Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Daria L.; Beltrán-Suito, Rodrigo; Thomsen, Julianne M.

2016-02-05

This paper introduces IrI(CO)2(pyalc) (pyalc = (2-pyridyl)-2-propanoate) as an atom-efficient precursor for Ir-based homogeneous oxidation catalysis. This compound was chosen to simplify analysis of the water oxidation catalyst species formed by the previously reported Cp*IrIII(pyalc)OH water oxidation precatalyst. Here, we present a comparative study on the chemical and catalytic properties of these two precursors. Previous studies show that oxidative activation of Cp*Ir-based precursors with NaIO4 results in formation of a blue IrIV species. This activation is concomitant with the loss of the placeholder Cp* ligand which oxidatively degrades to form acetic acid, iodate, and other obligatory byproducts. The activation processmore » requires substantial amounts of primary oxidant, and the degradation products complicate analysis of the resulting IrIV species. The species formed from oxidation of the Ir(CO)2(pyalc) precursor, on the other hand, lacks these degradation products (the CO ligands are easily lost upon oxidation) which allows for more detailed examination of the resulting Ir(pyalc) active species both catalytically and spectroscopically, although complete structural analysis is still elusive. Once Ir(CO)2(pyalc) is activated, the system requires acetic acid or acetate to prevent the formation of nanoparticles. Investigation of the activated bis-carbonyl complex also suggests several Ir(pyalc) isomers may exist in solution. By 1H NMR, activated Ir(CO)2(pyalc) has fewer isomers than activated Cp*Ir complexes, allowing for advanced characterization. Future research in this direction is expected to contribute to a better structural understanding of the active species. A diol crystallization agent was needed for the structure determination of 3.« less

Rapid discrimination of three Uighur medicine of Eremurus by FT-IR combined with 2DCOS-IR

NASA Astrophysics Data System (ADS)

Zhu, Yun; Xu, Chang-hua; Huang, Jian; Li, Guo-yu; Zhou, Qun; Liu, Xin-Hu; Sun, Su-qin; Wang, Jin-hui

2014-07-01

As complicated mixture systems, traditional Chinese medicines (TCMs) are difficult to be identified and discriminated, especially for the drug samples originated from the same source. In this study, a tri-step infrared spectroscopy method, i.e., conventional infrared spectroscopy (FT-IR) combined with second derivatives spectra and two-dimensional correlation infrared spectroscopy (2DCOS-IR), was employed to study and identify three Uighur drugs of Eremurus in Xinjiang, i.e. Eremurus altaicus (Pall.) Stev (AET), E. inderiensis (M.Bieb.)Regel(CB), E. anisopterus (Kar.et Kir.) Regel(YC). It was founded that the conventional IR spectra of the three species Eremurus were very similar based on the peak positions and shapes, indicating that the three had similar chemical profiles. On the basis of the different IR spectra of reference compounds and microscopic identification, the roots of YC, CB and AET all have comparable amount of calcium oxalate. The second derivative spectra of Eremurus enhanced the spectral resolution and amplified the small differences, especially at about 1468 cm-1, 1454 cm-1, and 1164 cm-1, and subsequently provided some dissimilarity in their calcium oxalate content. AET has relatively higher content of calcium oxalate but the lower content of anthraquinones. Moreover, the 2D-IR spectra revealed tiny differences among the three species by providing dynamic structural information of their chemical components in a more direct and visual way. The differences embodied mainly on the intensity of the auto-peaks at 971 cm-1, 1008 cm-1, 1468 cm-1 and 1578 cm-1. As a result, it was demonstrated that the macroscopic IR fingerprint method could discriminate the three similar Uighur drugs, YC, CB and AET.

Infrared spectral imaging as a novel approach for histopathological recognition in colon cancer diagnosis

NASA Astrophysics Data System (ADS)

Nallala, Jayakrupakar; Gobinet, Cyril; Diebold, Marie-Danièle; Untereiner, Valérie; Bouché, Olivier; Manfait, Michel; Sockalingum, Ganesh Dhruvananda; Piot, Olivier

2012-11-01

Innovative diagnostic methods are the need of the hour that could complement conventional histopathology for cancer diagnosis. In this perspective, we propose a new concept based on spectral histopathology, using IR spectral micro-imaging, directly applied to paraffinized colon tissue array stabilized in an agarose matrix without any chemical pre-treatment. In order to correct spectral interferences from paraffin and agarose, a mathematical procedure is implemented. The corrected spectral images are then processed by a multivariate clustering method to automatically recover, on the basis of their intrinsic molecular composition, the main histological classes of the normal and the tumoral colon tissue. The spectral signatures from different histological classes of the colonic tissues are analyzed using statistical methods (Kruskal-Wallis test and principal component analysis) to identify the most discriminant IR features. These features allow characterizing some of the biomolecular alterations associated with malignancy. Thus, via a single analysis, in a label-free and nondestructive manner, main changes associated with nucleotide, carbohydrates, and collagen features can be identified simultaneously between the compared normal and the cancerous tissues. The present study demonstrates the potential of IR spectral imaging as a complementary modern tool, to conventional histopathology, for an objective cancer diagnosis directly from paraffin-embedded tissue arrays.

Experiment research on infrared targets signature in mid and long IR spectral bands

NASA Astrophysics Data System (ADS)

Wang, Chensheng; Hong, Pu; Lei, Bo; Yue, Song; Zhang, Zhijie; Ren, Tingting

2013-09-01

Since the infrared imaging system has played a significant role in the military self-defense system and fire control system, the radiation signature of IR target becomes an important topic in IR imaging application technology. IR target signature can be applied in target identification, especially for small and dim targets, as well as the target IR thermal design. To research and analyze the targets IR signature systematically, a practical and experimental project is processed under different backgrounds and conditions. An infrared radiation acquisition system based on a MWIR cooled thermal imager and a LWIR cooled thermal imager is developed to capture the digital infrared images. Furthermore, some instruments are introduced to provide other parameters. According to the original image data and the related parameters in a certain scene, the IR signature of interested target scene can be calculated. Different background and targets are measured with this approach, and a comparison experiment analysis shall be presented in this paper as an example. This practical experiment has proved the validation of this research work, and it is useful in detection performance evaluation and further target identification research.

ATR-IR study of skin components: Lipids, proteins and water. Part I: Temperature effect

NASA Astrophysics Data System (ADS)

Olsztyńska-Janus, S.; Pietruszka, A.; Kiełbowicz, Z.; Czarnecki, M. A.

2018-01-01

In this work we report the studies of the effect of temperature on skin components, such as lipids, proteins and water. Modifications of lipids structure induced by increasing temperature (from 20 to 90 °C) have been studied using ATR-IR (Attenuated Total Reflectance Infrared) spectroscopy, which is a powerful tool for characterization of the molecular structure and properties of tissues, such as skin. Due to the small depth of penetration (0.6-5.6 μm), ATR-IR spectroscopy probes only the outermost layer of the skin, i.e. the stratum corneum (SC). The assignment of main spectral features of skin components allows for the determination of phase transitions from the temperature dependencies of band intensities [e.g. νas(CH2) and νs(CH2)]. The phase transitions were determined by using two methods: the first one was based on the first derivative of the Boltzmann function and the second one employed tangent lines of sigmoidal, aforementioned dependencies. The phase transitions in lipids were correlated with modifications of the structure of water and proteins.

Potential for enhancing external beam radiotherapy for lung cancer using high-Z nanoparticles administered via inhalation

NASA Astrophysics Data System (ADS)

Hao, Yao; Altundal, Yucel; Moreau, Michele; Sajo, Erno; Kumar, Rajiv; Ngwa, Wilfred

2015-09-01

Nanoparticle-aided radiation therapy is emerging as a promising modality to enhance radiotherapy via the radiosensitizing action of high atomic number (Z) nanoparticles. However, the delivery of sufficiently potent concentrations of such nanoparticles to the tumor remain a challenge. This study investigates the dose enhancement to lung tumors due to high-Z nanoparticles (NPs) administered via inhalation during external beam radiotherapy. Here NPs investigated include: cisplatin nanoparticles (CNPs), carboplatin nanoparticles (CBNPs), and gold nanoparticles (GNPs). Using Monte Carlo-generated megavoltage energy spectra, a previously employed analytic method was used to estimate dose enhancement to lung tumors due to radiation-induced photoelectrons from the NPs administered via inhalation route (IR) in comparison to intravenous (IV) administration. Previous studies have indicated about 5% of FDA-approved cisplatin concentrations reach the lung via IV. Meanwhile recent experimental studies indicate that 3.5-14.6 times higher concentrations of NPs can reach the lung by IR compared to IV. Taking these into account, the dose enhancement factor (DEF) defined as the ratio of the radiotherapy dose with and without nanoparticles was calculated for a range of NPs concentrations and tumor sizes. The DEF for IR was then compared with that for IV. For IR with 3.5 times higher concentrations than IV, and 2 cm diameter tumor, clinically significant DEF values of up to 1.19, 1.26, and 1.51 were obtained for CNPs, CBNPs and GNPs. In comparison values of 1.06, 1.08, and 1.15 were obtained via IV administration. For IR with 14.6 times higher concentrations, even higher DEF values were obtained e.g. 1.81 for CNPs. Results also showed that the DEF increased with increasing field size or decreasing tumor volume, as expected. The results of this work indicate that IR administration of targeted high-Z CNPs/CBNPs/GNPs could enable clinically significant DEF to lung tumors compared to IV

Spectral and Vertical Distribution Properties of Titan's Particulates from Thermal-IR CIRS Data: Physical Implications

NASA Technical Reports Server (NTRS)

Anderson, Carrie M.; Samuelson, Robert; Vinatier, Sandrine

2011-01-01

Analyses of far-IR spectra between 20 and 560/cm (500 and 18 micron) recorded by the Cassini Composite Infrared Spectrometer (CIRS) yield the spectral dependence and the vertical distribution of Titan's photochemical aerosol and stratospheric ice clouds. Below the stratopause (approx. 300 km) the aerosol appears to be incompletely mixed for the following reasons: 1) the altitude dependence of the aerosol mass absorption coefficient is larger at higher altitudes than at lower altitudes, 2} the aerosol scale height varies with altitude, which implies some kind of layering effect, and 3) the aerosol abundance varies with latitude. The spectral shape of the aerosol opacity appears to be independent in altitude and latitude below the stratopause, even though inhomogeneities in the abundance appear to be prevalent throughout this altitude region. This implies that aerosol chemistry is restricted to altitude regions above the stratopause, where pressures are less than approx 0.1 mbar. The aerosol exhibits an extremely broad emisSion feature with a spectral peak at 140/cm (71 micron), which is not evident in laboratory simulated Titan aerosols (tholin) that are created at pressures greater than 0.1 mbar. A strong broad emission feature centered roughly around 160 cm-1 corresponds very closely to those found in nitrile ice spectra. This feature is pervasive throughout the region from high northern to high southern latitudes. The inference of nitrile ices is consistent with the highly restricted altitude ranges over which these features are observed, and appear to be dominated by HCN and HC3N. At low and moderate latitudes these clouds are observed to be located between 60 and 100 km, whereas at high northern latitudes during northern winter these clouds are observed at altitudes between 150 and 165 km. The ubiquitous nature of these nitrile ice clouds is inconsistent with a simple meridional circulation concept, suggesting that the true dynamical situation is more complex.

Ir Spectroscopic Studies on Microsolvation of HCl by Water

NASA Astrophysics Data System (ADS)

Mani, Devendra; Schwan, Raffael; Fischer, Theo; Dey, Arghya; Kaufmann, Matin; Redlich, Britta; van der Meer, Lex; Schwaab, Gerhard; Havenith, Martina

2016-06-01

Acid dissociation reactions are at the heart of chemistry. These reactions are well understood at the macroscopic level. However, a microscopic level understanding is still in the early stages of development. Questions such as 'how many H_2O molecules are needed to dissociate one HCl molecule?' have been posed and explored both theoretically and experimentally.1-5 Most of the theoretical calculations predict that four H_2O molecules are sufficient to dissociate one HCl molecule, resulting in the formation of a solvent separated H_3O+(H_2O)3Cl- cluster.1-3 IR spectroscopy in helium nanodroplets has earlier been used to study this dissociation process.3-5 However, these studies were carried out in the region of O-H and H-Cl stretch, which is dominated by the spectral features of undissociated (HCl)m-(H_2O)n clusters. This contributed to the ambiguity in assigning the spectral features arising from the dissociated cluster.4,5 Recent predictions from Bowman's group, suggest the presence of a broad spectral feature (1300-1360 wn) for the H_3O+(H_2O)3Cl- cluster, corresponding to the umbrella motion of H_3O+ moiety.6 This region is expected to be free from the spectral features due to the undissociated clusters. In conjunction with the FELIX laboratory, we have performed experiments on the (HCl)m(H_2O)n (m=1-2, n≥4) clusters, aggregated in helium nanodroplets, in the 900-1700 wn region. Mass selective measurements on these clusters revealed the presence of a weak-broad feature which spans between 1000-1450 wn and depends on both HCl as well as H_2O concentration. Measurements are in progress for the different deuterated species. The details will be presented in the talk. References: 1) C.T. Lee et al., J. Chem. Phys., 104, 7081 (1996). 2) H. Forbert et al., J. Am. Chem. Soc., 133, 4062 (2011). 3) A. Gutberlet et al., Science, 324, 1545 (2009). 4) S. D. Flynn et al., J. Phys. Chem. Lett., 1, 2233 (2010). 5) M. Letzner et al., J. Chem. Phys., 139, 154304 (2013). 6) J. M

Allophane on Mars: Evidence from IR Spectroscopy and TES Spectral Models

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Rampe, E. B.; Kraft, M. D.; Sharp. T. G.; Golden, D. C.; Christensen, P. C.

2010-01-01

Allophane is an alteration product of volcanic glass and a clay mineral precursor that is commonly found in basaltic soils on Earth. It is a poorly-crystalline or amorphous, hydrous aluminosilicate with Si/Al ratios ranging from approx.0.5-1 [Wada, 1989]. Analyses of thermal infrared (TIR) spectra of the Martian surface from TES show high-silica phases at mid-to-high latitudes that have been proposed to be primary volcanic glass [Bandfield et al., 2000; Bandfield, 2002; Rogers and Christensen, 2007] or poorly-crystalline secondary silicates such as allophane or aluminous amorphous silica [Kraft et al., 2003; Michalski et al., 2006; Rogers and Christensen, 2007; Kraft, 2009]. Phase modeling of chemical data from the APXS on the Mars Exploration Rover Spirit suggest the presence of allophane in chemically weathered rocks [Ming et al., 2006]. The presence of allophane on Mars has not been previously tested with IR spectroscopy because allophane spectra have not been available. We synthesized allophanes and allophanic gels with a range of Si/Al ratios to measure TIR emission and VNIR reflectance spectra and to test for the presence of allophane in Martian soils. VNIR reflectance spectra of the synthetic allophane samples have broad absorptions near 1.4 m from OH stretching overtones and 1.9 m from a combination of stretching and bending vibrations in H2O. Samples have a broad absorption centered near 2.25 microns, from AlAlOH combination bending and stretching vibrations, that shifts position with Si/Al ratio. Amorphous silica (opaline silica or primary volcanic glass) has been identified in CRISM spectra of southern highland terrains based on the presence of 1.4, 1.9, and broad 2.25 m absorptions [Mustard et al., 2008]; however, these absorptions are also consistent with the presence of allophane. TIR emission spectra of the synthetic allophanes show two spectrally distinct types: Si-rich and Al-rich. Si-rich allophanes have two broad absorptions centered near 1080

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

NASA Astrophysics Data System (ADS)

de Julián Fernández, C.; Mattei, G.; Paz, E.; Novak, R. L.; Cavigli, L.; Bogani, L.; Palomares, F. J.; Mazzoldi, P.; Caneschi, A.

2010-04-01

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO2 matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles.

PubMed

de Julián Fernández, C; Mattei, G; Paz, E; Novak, R L; Cavigli, L; Bogani, L; Palomares, F J; Mazzoldi, P; Caneschi, A

2010-04-23

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO(2) matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Probing the Invisible Universe: The Case for Far-IR/Submillimeter Interferometry

NASA Technical Reports Server (NTRS)

Leisawitz, D.; Armstrong, T.; Benford, D. J.; Blain, A.; Borne, K.; Danchi, W.; Evans, N.; Gardner, J.; Gezari, D.; Harwit, M.

2004-01-01

The question "How did we get here and what will the future bring?"captures the human imagination and the attention of the National Academy of Science's Astronomy and Astrophysics Survey Committee (AASC). Fulfillment of this fundamental goal requires astronomers to have sensitive, high angular and spectral resolution observations in the far-infrared/submillimeter (far- IR/sub-mm) spectral region. With half the luminosity of the universe and vital information about galaxy, star and planet formation, observations in this spectral region require capabilities similar to those currently available or planned at shorter wavelengths. In this paper we summarize the scientific motivation, some mission concepts and technology requirements for far-IR/sub-mm space interferometers that can be developed in the 2010-2020 timeframe.

Probing The Invisible Universe: The Case for Far-IR/Submillimeter Interferometry

NASA Technical Reports Server (NTRS)

Leisawitz, D.; Armstrong, T; Benford, D.; Blain, A.; Borne, K.; Danchi, W.; Evans, N.; Gardner, J.; Gezari, D.; Harwit, M.

2003-01-01

The question "How did we get here and what will the future bring? captures the human imagination and the attention of the National Academy of Science s Astronomy and Astrophysics Survey Committee (AASC). Fulfillment of this fundamental goal requires astronomers to have sensitive, high angular and spectral resolution observations in the far-infrared submillimeter (far-IR-sub-mm) spectral region. With half the luminosity of the universe and vital information about galaxy, star and planet formation, observations in this spectral region require capabilities similar to those currently available or planned at shorter wavelengths. The scientific motivation, some mission concepts and technology requirements for far-IR-sub-mm space interferometers that can be developed in the 2010-2020 timeframe are summarized.

Evaluation of the treatment with resveratrol-loaded nanoparticles in intestinal injury model caused by ischemia and reperfusion.

PubMed

Borges, Stephanie Carvalho; Ferreira, Paulo Emílio Botura; da Silva, Luisa Mota; de Paula Werner, Maria Fernanda; Irache, Juan Manuel; Cavalcanti, Osvaldo Albuquerque; Buttow, Nilza Cristina

2018-03-01

The gastrointestinal tract is extremely sensitive to ischemia and reperfusion (I/R). Studies have reported that resveratrol (RSV) is able to combat damage caused by intestinal I/R. Because of its effectiveness in increasing the permanence and bioavailability of resveratrol in the intestinal epithelium, we investigated whether the effect of resveratrol-loaded in poly(anhydride) nanoparticles reduce oxidative stress and promote myenteric neuroprotection in the ileum of rats subjected to I/R. Physicochemical evaluations were performed on nanoparticles. The animals were divided into nine groups (n = 6/group) and treated every 48 h. Treatments with resveratrol (7 mg/kg of body weight) were applied 5 days before surgery and continued for 7 days after surgery (reperfusion period). The superior mesenteric artery was occluded to cause I/R injury. Oxidative stress, myeloperoxidase, nitrite, aspartate aminotransferase, alanine aminotransferase, immunolabeling of myenteric neurons and glial cells, and gastrointestinal transit was evaluated. Both nanoparticle formulations presented negative charge with homogeneous distribution, and the payload, showed an encapsulation efficiency of 60%. Resveratrol administered in free form prevented alterations that were caused by I/R. The results of the groups treated with RSV-loaded nanoparticles presented similar results to the group treated with free resveratrol. Treatment with empty nanoparticles showed that poly(anhydride) is not an ideal nanocarrier for application in in vivo models of intestinal I/R injury, because of hepatotoxicity that may be caused by epithelial barrier dysfunction that triggers the translocation of nanoparticles. Copyright © 2018 Elsevier B.V. All rights reserved.

Group 12 dithiocarbamate complexes: synthesis, spectral studies and their use as precursors for metal sulfides nanoparticles and nanocomposites.

PubMed

Ajibade, Peter A; Ejelonu, Benjamin C

2013-09-01

Zn(II), Cd(II) and Hg(II) dithiocarbamate complexes have been synthesized and characterized by elemental analysis, thermogravimetric analysis, UV-Vis, FTIR, (1)H- and (13)C NMR spectroscopy. The complexes were thermolysed at 180 °C and used as single molecule precursors for the synthesis of HDA capped ZnS, CdS and HgS nanoparticles and polymethylmethacrylate (PMMA) nanocomposites. The optical and structural properties of the nanoparticles and nanocomposites were studied by UV-Vis, PL, XRD and SEM. The crystallites sizes of the nanoparticles varied between 3.03 and 23.45 nm. SEM and EDX analyses of the nanocomposites confirmed the presence of the nanoparticles in the polymer matrix. Copyright © 2013 Elsevier B.V. All rights reserved.

Mid-IR laser system for advanced neurosurgery

NASA Astrophysics Data System (ADS)

Klosner, M.; Wu, C.; Heller, D. F.

2014-03-01

We present work on a laser system operating in the near- and mid-IR spectral regions, having output characteristics designed to be optimal for cutting various tissue types. We provide a brief overview of laser-tissue interactions and the importance of controlling certain properties of the light beam. We describe the principle of operation of the laser system, which is generally based on a wavelength-tunable alexandrite laser oscillator/amplifier, and multiple Raman conversion stages. This configuration provides robust access to the mid-IR spectral region at wavelengths, pulse energies, pulse durations, and repetition rates that are attractive for neurosurgical applications. We summarize results for ultra-precise selective cutting of nerve sheaths and retinas with little collateral damage; this has applications in procedures such as optic-nerve-sheath fenestration and possible spinal repair. We also report results for cutting cornea, and dermal tissues.

Green synthesis of silver nanoparticles using Terminalia chebula extract at room temperature and their antimicrobial studies

NASA Astrophysics Data System (ADS)

Mohan Kumar, Kesarla; Sinha, Madhulika; Mandal, Badal Kumar; Ghosh, Asit Ranjan; Siva Kumar, Koppala; Sreedhara Reddy, Pamanji

2012-06-01

A green rapid biogenic synthesis of silver nanoparticles (Ag NPs) using Terminalia chebula (T. chebula) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 452 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by T. chebula extract was completed within 20 min which was evidenced potentiometrically. Synthesised nanoparticles were characterised using UV-vis spectroscopy, Fourier transformed infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The hydrolysable tannins such as di/tri-galloyl-glucose present in the extract were hydrolyzed to gallic acid and glucose that served as reductant while oxidised polyphenols acted as stabilizers. In addition, it showed good antimicrobial activity towards both Gram-positive bacteria (S. aureus ATCC 25923) and Gram-negative bacteria (E. coli ATCC 25922). Industrially it may be a smart option for the preparation of silver nanoparticles.

Electrochemical synthesis and characterization of zinc oxalate nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com; Roushani, Mahmoud; Department of Chemistry, Ilam University, Ilam

2013-03-15

Highlights: ► Synthesis of zinc oxalate nanoparticles via electrolysis of a zinc plate anode in sodium oxalate solutions. ► Design of a Taguchi orthogonal array to identify the optimal experimental conditions. ► Controlling the size and shape of particles via applied voltage and oxalate concentration. ► Characterization of zinc oxalate nanoparticles by SEM, UV–vis, FT-IR and TG–DTA. - Abstract: A rapid, clean and simple electrodeposition method was designed for the synthesis of zinc oxalate nanoparticles. Zinc oxalate nanoparticles in different size and shapes were electrodeposited by electrolysis of a zinc plate anode in sodium oxalate aqueous solutions. It was foundmore » that the size and shape of the product could be tuned by electrolysis voltage, oxalate ion concentration, and stirring rate of electrolyte solution. A Taguchi orthogonal array design was designed to identify the optimal experimental conditions. The morphological characterization of the product was carried out by scanning electron microscopy. UV–vis and FT-IR spectroscopies were also used to characterize the electrodeposited nanoparticles. The TG–DTA studies of the nanoparticles indicated that the main thermal degradation occurs in two steps over a temperature range of 350–430 °C. In contrast to the existing methods, the present study describes a process which can be easily scaled up for the production of nano-sized zinc oxalate powder.« less

Optical Characterization of Single Plasmonic Nanoparticles

PubMed Central

Olson, Jana; Dominguez-Medina, Sergio; Hoggard, Anneli; Wang, Lin-Yung; Chang, Wei-Shun; Link, Stephan

2015-01-01

This tutorial review surveys the optical properties of plasmonic nanoparticles studied by various single particle spectroscopy techniques. The surface plasmon resonance of metallic nanoparticles depends sensitively on the nanoparticle geometry and its environment, with even relatively minor deviations causing significant changes in the optical spectrum. Because for chemically prepared nanoparticles a distribution of their size and shape is inherent, ensemble spectra of such samples are inhomogeneously broadened, hiding the properties of the individual nanoparticles. The ability to measure one nanoparticle at a time using single particle spectroscopy can overcome this limitation. This review provides an overview of different steady-state single particle spectroscopy techniques that provide detailed insight into the spectral characteristics of plasmonic nanoparticles. PMID:24979351

Resolution study of imaging in nanoparticle optical phantoms

NASA Astrophysics Data System (ADS)

Ortiz-Rascón, E.; Bruce, N. C.; Flores-Flores, J. O.; Sato-Berru, R.

2011-08-01

We present results of resolution and optical characterization studies of silicon dioxide nanoparticle solutions. These phantoms consist of spherical particles with a mean controlled diameter of 168 and 429 nm. The importance of this work lies in using these solutions to develop phantoms with optical properties that closely match those of human breast tissue at near-IR wavelengths, and also to compare different resolution criteria for imaging studies at these wavelengths. Characterization involves illuminating the solution with a laser beam transmitted through a recipient of known width containing the solution. Resulting intensity profiles from the light spot are measured as function of the detector position. Measured intensity profiles were fitted to the calculated profiles obtained from diffusion theory, using the method of images. Fitting results give us the absorption and transport scattering coefficients. These coefficients can be modified by changing the particle concentration of the solution. We found that these coefficients are the same order of magnitude as those of human tissue reported in published studies. The resolution study involves measuring the edge response function (ERF) for a mask embedded on the nanoparticle solutions and fitting it to the calculated ERF, obtaining the resolution for the Hebden, Sparrow and Bentzen criteria.

HOMA1-IR and HOMA2-IR indexes in identifying insulin resistance and metabolic syndrome: Brazilian Metabolic Syndrome Study (BRAMS).

PubMed

Geloneze, Bruno; Vasques, Ana Carolina Junqueira; Stabe, Christiane França Camargo; Pareja, José Carlos; Rosado, Lina Enriqueta Frandsen Paez de Lima; Queiroz, Elaine Cristina de; Tambascia, Marcos Antonio

2009-03-01

To investigate cut-off values for HOMA1-IR and HOMA2-IR to identify insulin resistance (IR) and metabolic syndrome (MS), and to assess the association of the indexes with components of the MS. Nondiabetic subjects from the Brazilian Metabolic Syndrome Study were studied (n = 1,203, 18 to 78 years). The cut-off values for IR were determined from the 90th percentile in the healthy group (n = 297) and, for MS, a ROC curve was generated for the total sample. In the healthy group, HOMA-IR indexes were associated with central obesity, triglycerides and total cholesterol (p < 0.001). The cut-off values for IR were: HOMA1-IR > 2.7 and HOMA2-IR > 1.8; and, for MS were: HOMA1-IR > 2.3 (sensitivity: 76.8%; specificity: 66.7%) and HOMA2-IR > 1.4 (sensitivity: 79.2%; specificity: 61.2%). The cut-off values identified for HOMA1-IR and HOMA2-IR indexes have a clinical and epidemiological application for identifying IR and MS in Westernized admixtured multi-ethnic populations.

Absorption Spectra of Gold Nanoparticle Suspensions

NASA Astrophysics Data System (ADS)

Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

2018-02-01

Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

Using Fourier transform IR spectroscopy to analyze biological materials

PubMed Central

Baker, Matthew J; Trevisan, Júlio; Bassan, Paul; Bhargava, Rohit; Butler, Holly J; Dorling, Konrad M; Fielden, Peter R; Fogarty, Simon W; Fullwood, Nigel J; Heys, Kelly A; Hughes, Caryn; Lasch, Peter; Martin-Hirsch, Pierre L; Obinaju, Blessing; Sockalingum, Ganesh D; Sulé-Suso, Josep; Strong, Rebecca J; Walsh, Michael J; Wood, Bayden R; Gardner, Peter; Martin, Francis L

2015-01-01

IR spectroscopy is an excellent method for biological analyses. It enables the nonperturbative, label-free extraction of biochemical information and images toward diagnosis and the assessment of cell functionality. Although not strictly microscopy in the conventional sense, it allows the construction of images of tissue or cell architecture by the passing of spectral data through a variety of computational algorithms. Because such images are constructed from fingerprint spectra, the notion is that they can be an objective reflection of the underlying health status of the analyzed sample. One of the major difficulties in the field has been determining a consensus on spectral pre-processing and data analysis. This manuscript brings together as coauthors some of the leaders in this field to allow the standardization of methods and procedures for adapting a multistage approach to a methodology that can be applied to a variety of cell biological questions or used within a clinical setting for disease screening or diagnosis. We describe a protocol for collecting IR spectra and images from biological samples (e.g., fixed cytology and tissue sections, live cells or biofluids) that assesses the instrumental options available, appropriate sample preparation, different sampling modes as well as important advances in spectral data acquisition. After acquisition, data processing consists of a sequence of steps including quality control, spectral pre-processing, feature extraction and classification of the supervised or unsupervised type. A typical experiment can be completed and analyzed within hours. Example results are presented on the use of IR spectra combined with multivariate data processing. PMID:24992094

Anionic 11-mercaptoundecanoic acid capped ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Šimšíková, Michaela; Antalík, Marián; Kaňuchová, Mária; Škvarla, Jiří

2013-10-01

The anionic zinc oxide nanoparticles have been prepared at room temperature by a precipitation method using ZnCl2 and NaOH and surface modification with 11-mercaptoundecanoic acid (MUA). Atomic force microscopy (AFM) was used for definition of morphology and size of prepared nanoparticles which was proved by measurements of particle size distribution using Zetasizer. Successful coating with MUA as surfactant was acknowledged by X-ray photoelectron spectroscopy and ATR FT-IR spectroscopy. The isoelectric point (IEP) of ZnO-MUA nanoparticles was obtained by measurements of zeta potential and FT-IR dependence on pH; the obtained value was approximately 3.58. The value of exchanged protons was 2.88 which indicates a positive binding cooperativity of modified nanoparticles.

Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines

NASA Astrophysics Data System (ADS)

Raouafi, Nour E.; Riley, Pete; Gibson, Sarah; Fineschi, Silvano; Solanki, Sami K.

2016-06-01

The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. This makes the development of measurement methods of coronal magnetic fields a high priority in solar physics. The Hanle effect in the UV and IR spectral lines is a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations to study the magnitude of the signal to be expected for typical coronal magnetic fields for selected spectral lines in the UV and IR wavelength ranges, namely the HI Ly-α and the He I 10830 Å lines. We show that the selected lines are useful for reliable diagnosis of coronal magnetic fields. The results show that the combination of polarization measurements of spectral lines with different sensitivities to the Hanle effect may be most appropriate for deducing coronal magnetic properties from future observations.

Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

PubMed

Sadeghi, Babak; Mohammadzadeh, M; Babakhani, B

2015-07-01

Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR). Copyright © 2015 Elsevier B.V. All rights reserved.

Polymer-encapsulated metal nanoparticles: optical, structural, micro-analytical and hydrogenation studies of a composite material.

PubMed

Scalzullo, Stefania; Mondal, Kartick; Witcomb, Mike; Deshmukh, Amit; Scurrell, Mike; Mallick, Kaushik

2008-02-20

A single-step synthesis route is described for the preparation of a metal-polymer composite in which palladium acetate and meta-amino benzoic acid were used as the precursors for palladium nanoparticles and poly(meta-amino benzoic acid) (PABA). The palladium nanoparticles were found to be uniformly dispersed and highly stabilized throughout the macromolecule matrix. The resultant composite material was characterized by means of different techniques, such as IR and Raman spectroscopy, which provided information regarding the chemical structure of the polymer, whereas electron microscopy images yielded information regarding the morphology of the composite material and the distribution of the metal particles in the composite material. The composite material was used as a catalyst for the ethylene hydrogenation reaction and showed catalytic activity at higher temperatures. TEM studies confirmed the changed environment of the nanoparticles at these temperatures.

Photo-Redox Activated Drug Delivery Systems Operating Under Two Photon Excitation in the Near-IR

PubMed Central

Guardado-Alvarez, Tania M.; Devi, Lekshmi Sudha; Vabre, Jean-Marie; Pecorelli, Travis; Schwartz, Benjamin J.; Durand, Jean-Olivier; Mongin, Olivier; Blanchard-Desce, Mireille; Zink, Jeffrey I.

2014-01-01

We report the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by “snap-top” caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes inter-molecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. We describe the operation of the “snap-top” release mechanism by both one- and two-photon activation. This system presents a proof of concept of a near-IR photoredox-induced nanoparticle delivery system that may lead to a new type of photodynamic drug release therapy. PMID:24647752

Photo-redox activated drug delivery systems operating under two photon excitation in the near-IR.

PubMed

Guardado-Alvarez, Tania M; Devi, Lekshmi Sudha; Vabre, Jean-Marie; Pecorelli, Travis A; Schwartz, Benjamin J; Durand, Jean-Olivier; Mongin, Olivier; Blanchard-Desce, Mireille; Zink, Jeffrey I

2014-05-07

We report the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by "snap-top" caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes inter-molecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. We describe the operation of the "snap-top" release mechanism by both one- and two-photon activation. This system presents a proof of concept of a near-IR photoredox-induced nanoparticle delivery system that may lead to a new type of photodynamic drug release therapy.

Photocatalytic studies of electrochemically synthesized polysaccharide-functionalized ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Kaur, Simranjeet; Kaur, Harpreet

2018-05-01

The present work reports the electrochemical synthesis of polysaccharide-functionalized ZnO nanoparticles using sodium hydroxide, starch, and zinc electrodes for the degradation of cationic dye (Rhodamine-B) under sunlight. Physiochemical properties of synthesized sample have been characterized by different techniques such as XRD, TEM, FESEM, EDS, IR, and UV-visible spectroscopic techniques. The influence of various factors such as effect of dye concentration, contact time, amount of photocatalyst, and pH has been studied. The results obtained from the photodegradation study showed that degradation rate of Rhodamine-B dye has been increased with increase of amount of photocatalyst and decreased with increase in initial dye concentration. Furthermore, the kinetics of the degradation has been investigated. It has been found that the photodegradation of Rhodamine-B dye follows pseudo-first-order kinetics and prepared photocatalyst can effectively degrade the cationic dye. Thus, this ecofriendly and efficient photocatalyst can be used for the treatment of dye-contaminated water. This catalyst also showed the antibacterial activity against Bacillus pumilus and Escherichia coli bacterial strains, so the synthesized nanoparticles also have the pharmaceutical properties.

Concepts for compact mid-IR spectroscopy in photochemistry

NASA Astrophysics Data System (ADS)

Cu-Nguyen, Phuong-Ha; Wang, Ziyu; Zappe, Hans

2016-11-01

Mid-infrared (IR) spectroscopy, typically 3 to 5 µm, is often the technology of choice to monitor the interaction between and concentration of molecules during photochemical reactions. However, classical mid-IR spectrometers are bulky, complex and expensive, making them unsuitable for use in the miniaturized microreactors increasingly being employed for chemical synthesis. We present here the concept for an ultra-miniaturized mid-IR spectrometer directly integrated onto a chemical microreactor to monitor the chemical reaction. The spectrometer is based on micro-machined Fabry-Perot resonator filters realized using pairs of Bragg mirrors to achieve a high spectral resolution. The fabrication of the optical filters is outlined and the measurement of transmittance spectra in the mid-IR range show a good agreement with theory and are thus promising candidates for a fully integrated system.

Biomimetic synthesis of silver nanoparticles by Citrus limon (lemon) aqueous extract and theoretical prediction of particle size.

PubMed

Prathna, T C; Chandrasekaran, N; Raichur, Ashok M; Mukherjee, Amitava

2011-01-01

In the present study, silver nanoparticles were rapidly synthesized at room temperature by treating silver ions with the Citrus limon (lemon) extract. The effect of various process parameters like the reductant concentration, mixing ratio of the reactants and the concentration of silver nitrate were studied in detail. In the standardized process, 10(-2)M silver nitrate solution was interacted for 4h with lemon juice (2% citric acid concentration and 0.5% ascorbic acid concentration) in the ratio of 1:4 (vol:vol). The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance as determined by UV-Visible spectra in the range of 400-500 nm. X-ray diffraction analysis revealed the distinctive facets (111, 200, 220, 222 and 311 planes) of silver nanoparticles. We found that citric acid was the principal reducing agent for the nanosynthesis process. FT-IR spectral studies demonstrated citric acid as the probable stabilizing agent. Silver nanoparticles below 50 nm with spherical and spheroidal shape were observed from transmission electron microscopy. The correlation between absorption maxima and particle sizes were derived for different UV-Visible absorption maxima (corresponding to different citric acid concentrations) employing "MiePlot v. 3.4". The theoretical particle size corresponding to 2% citric acid concentration was compared to those obtained by various experimental techniques like X-ray diffraction analysis, atomic force microscopy, and transmission electron microscopy. Copyright © 2010 Elsevier B.V. All rights reserved.

Optimization of Immunolabeled Plasmonic Nanoparticles for Cell Surface Receptor Analysis

PubMed Central

Seekell, Kevin; Price, Hillel; Marinakos, Stella; Wax, Adam

2011-01-01

Noble metal nanoparticles hold great potential as optical contrast agents due to a unique feature, known as the plasmon resonance, which produces enhanced scattering and absorption at specific frequencies. The plasmon resonance also provides a spectral tunability that is not often found in organic fluorophores or other labeling methods. The ability to functionalize these nanoparticles with antibodies has led to their development as contrast agents for molecular optical imaging. In this review article, we present methods for optimizing the spectral agility of these labels. We discuss synthesis of gold nanorods, a plasmonic nanoparticle in which the plasmonic resonance can be tuned during synthesis to provide imaging within the spectral window commonly utilized in biomedical applications. We describe recent advances in our group to functionalize gold and silver nanoparticles using distinct antibodies, including EGFR, HER-2 and IGF-1, selected for their relevance to tumor imaging. Finally, we present characterization of these nanoparticle labels to verify their spectral properties and molecular specificity. PMID:21911063

Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy

PubMed Central

Dhakal, Sagar; Chao, Kuanglin; Schmidt, Walter; Qin, Jianwei; Kim, Moon; Chan, Diane

2016-01-01

Turmeric powder (Curcuma longa L.) is valued both for its medicinal properties and for its popular culinary use, such as being a component in curry powder. Due to its high demand in international trade, turmeric powder has been subject to economically driven, hazardous chemical adulteration. This study utilized Fourier Transform-Raman (FT-Raman) and Fourier Transform-Infra Red (FT-IR) spectroscopy as separate but complementary methods for detecting metanil yellow adulteration of turmeric powder. Sample mixtures of turmeric powder and metanil yellow were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1%, and 0.01% (w/w). FT-Raman and FT-IR spectra were acquired for these mixture samples as well as for pure samples of turmeric powder and metanil yellow. Spectral analysis showed that the FT-IR method in this study could detect the metanil yellow at the 5% concentration, while the FT-Raman method appeared to be more sensitive and could detect the metanil yellow at the 1% concentration. Relationships between metanil yellow spectral peak intensities and metanil yellow concentration were established using representative peaks at FT-Raman 1406 cm−1 and FT-IR 1140 cm−1 with correlation coefficients of 0.93 and 0.95, respectively. PMID:28231130

Silica nanoparticles with a substrate switchable luminescence

NASA Astrophysics Data System (ADS)

Bochkova, O. D.; Mustafina, A. R.; Fedorenko, S. V.; Konovalov, A. I.

2011-04-01

Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required step for the gaining to these nanoparticles marking and sensing functions. Thus covalent and non-covalent surface modification of these nanoparticles was developed to provide the binding with biotargets and sensing of anions. The dicationic surfactant coating of negatively charged Tb(III)-TCAS doped silica nanoparticles was chosen as the basis for the anion responsible system. The reversible insertion of the quenching anions (namely phenol red) into the surfactant based layer at the surface of luminescent nanoparticles switches off the Tb-centered luminescence. In turn the reversible reestablishment of the luminescence results from the competitive insertion of the non-quenching anions into the surfactant layer at the silica/water interface. The hydrophobic anions exemplified by dodecylsulfates versus hydrophilic ones (hydrophosphates) are preferable in the competition with phenol red anions.

Characterization and identification of microorganisms by FT-IR microspectrometry

NASA Astrophysics Data System (ADS)

Ngo-Thi, N. A.; Kirschner, C.; Naumann, D.

2003-12-01

We report on a novel FT-IR approach for microbial characterization/identification based on a light microscope coupled to an infrared spectrometer which offers the possibility to acquire IR-spectra of microcolonies containing only few hundred cells. Microcolony samples suitable for FT-IR microspectroscopic measurements were obtained by a replica technique with a stamping device that transfers spatially accurate cells of microcolonies growing on solid culture plates to a special, IR-transparent or reflecting stamping plate. High quality spectra could be recorded either by applying the transmission/absorbance or the reflectance/absorbance mode of the infrared microscope. Signal to noise ratios higher than 1000 were obtained for microcolonies as small as 40 μm in diameter. Reproducibility levels were established that allowed species and strain identification. The differentiation and classification capacity of the FT-IR microscopic technique was tested for different selected microorganisms. Cluster and factor analysis methods were used to evaluate the complex spectral data. Excellent discrimination between bacteria and yeasts, and at the same time Gram-negative and Gram-positive bacterial strains was obtained. Twenty-two selected strains of different species within the genus Staphylococcus were repetitively measured and could be grouped into correct species cluster. Moreover, the results indicated that the method allows also identifications at the subspecies level. Additionally, the new approach allowed spectral mapping analysis of single colonies which provided spatially resolved characterization of growth heterogeneity within complex microbial populations such as colonies.

Synthesis, spectral studies, antimicrobial, antioxidant and insect antifeedant activities of some 9 H-fluorene-2-yl keto-oxiranes

NASA Astrophysics Data System (ADS)

Thirunarayanan, G.; Vanangamudi, G.

2011-10-01

Thirteen ee (α S, β R) 9 H-fluorene-2-yl keto-oxiranes (2-(9 H)-fluorene-4-yl[3-(substituted phenyl)oxiran-2-yl]methanones) have been synthesized by phase transfer catalysed epoxidation of 9 H-fluorene-2-yl chalcones. The yields of oxiranes are more than 95%. The synthesized oxiranes have been characterized by IR, 1H, 13C and GC-MS spectral data. The spectral data are correlated with Hammett substituent constants and Swain-Lupton parameters. From the regression analysis, the effect of substituents on the group frequencies has been predicted. The antimicrobial, antioxidant and insect antifeedant activities of all the synthesized oxiranes have been studied.

A Sensitivity Study on the Effects of Particle Chemistry, Asphericity and Size on the Mass Extinction Efficiency of Mineral Dust in the Earth's Atmosphere: From the Near to Thermal IR

NASA Technical Reports Server (NTRS)

Hansell, R. A., Jr.; Reid, J. S.; Tsay, S. C.; Roush, T. L.; Kalashnikova, O. V.

2011-01-01

To determine a plausible range of mass extinction efficiencies (MEE) of terrestrial atmospheric dust from the near to thermal IR, sensitivity analyses are performed over an extended range of dust microphysical and chemistry perturbations. The IR values are subsequently compared to those in the near-IR, to evaluate spectral relationships in their optical properties. Synthesized size distributions consistent with measurements, model particle size, while composition is defined by the refractive indices of minerals routinely observed in dust, including the widely used OPAC/Hess parameterization. Single-scattering properties of representative dust particle shapes are calculated using the T-matrix, Discrete Dipole Approximation and Lorenz-Mie light-scattering codes. For the parameterizations examined, MEE ranges from nearly zero to 1.2 square meters per gram, with the higher values associated with non-spheres composed of quartz and gypsum. At near-IR wavelengths, MEE for non-spheres generally exceeds those for spheres, while in the thermal IR, shape-induced changes in MEE strongly depend on volume median diameter (VMD) and wavelength, particularly for MEE evaluated at the mineral resonant frequencies. MEE spectral distributions appear to follow particle geometry and are evidence for shape dependency in the optical properties. It is also shown that non-spheres best reproduce the positions of prominent absorption peaks found in silicates. Generally, angular particles exhibit wider and more symmetric MEE spectral distribution patterns from 8-10 micrometers than those with smooth surfaces, likely due to their edge-effects. Lastly, MEE ratios allow for inferring dust optical properties across the visible-IR spectrum. We conclude the MEE of dust aerosol are significant for the parameter space investigated, and are a key component for remote sensing applications and the study of direct aerosol radiative effects.

Green synthesis and spectral characterization of silver nanoparticles from Lakshmi tulasi (Ocimum sanctum) leaf extract

NASA Astrophysics Data System (ADS)

Subba Rao, Y.; Kotakadi, Venkata S.; Prasad, T. N. V. K. V.; Reddy, A. V.; Sai Gopal, D. V. R.

2013-02-01

A simple method for the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of Lakshmi tulasi (Ocimum sanctum) leaf as a reducing and stabilizing agent. AgNPs were rapidly synthesized using aqueous extract of tulasi leaf with AgNO3 solution within 15 min. The green synthesized AgNPs were characterized using physic-chemical techniques viz., UV-Vis, X-ray diffraction (XRD), scanning electron microscope (SEM) coupled with X-ray energy dispersive spectroscopy (EDX) and Fourier transform-infrared spectroscopy (FT-IR). Characterization data reveals that the particles were crystalline in nature and triangle shaped with an average size of 42 nm. The zeta potential of AgNPs were found to be -55.0 mV. This large negative zeta potential value indicates repulsion among AgNPs and their dispersion stability.

Study of transitional doubly-odd /sup 186/Ir and /sup 184/Ir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben Braham, A.; Bourgeois, C.; Kilcher, P.

1987-12-10

The transitional doubly-odd iridium nuclei with A = 184 and 186 have been studied from the ..beta../sup +//EC decay of the corresponding platinum isotopes using the on-line mass separator ISOCELE. Configurations can be reasonably Attributed to the low-lying states of /sup 184/Ir in agreement with results already known. On the other hand an E3 transition observed in /sup 186/Ir suggests that the known long-lived 1.7h 2/sup -/ state is located at 137.5 keV above the 16h 5/sup +/ state, raising questions about structure of this latter state.

Experimental Raman and IR spectral and theoretical studies of vibrational spectrum and molecular structure of Pantothenic acid (vitamin B5)

NASA Astrophysics Data System (ADS)

Srivastava, Mayuri; Singh, N. P.; Yadav, R. A.

2014-08-01

Vibrational spectrum of Pantothenic acid has been investigated using experimental IR and Raman spectroscopies and density functional theory methods available with the Gaussian 09 software. Vibrational assignments of the observed IR and Raman bands have been proposed in light of the results obtained from computations. In order to assign the observed IR and Raman frequencies the potential energy distributions (PEDs) have also been computed using GAR2PED software. Optimized geometrical parameters suggest that the overall symmetry of the molecule is C1. The molecule is found to possess eight conformations. Conformational analysis was carried out to obtain the most stable configuration of the molecule. In the present paper the vibrational features of the lowest energy conformer C-I have been studied. The two methyl groups have slightly distorted symmetries from C3V. The acidic Osbnd H bond is found to be the smallest one. To investigate molecular stability and bond strength we have used natural bond orbital analysis (NBO). Charge transfer occurs in the molecule have been shown by the calculated highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energies. The mapping of electron density iso-surface with electrostatic potential (ESP), has been carried out to get the information about the size, shape, charge density distribution and site of chemical reactivity of the molecule.

Raman scattering studies on PEG functionalized hydroxyapatite nanoparticles

NASA Astrophysics Data System (ADS)

Yamini, D.; Devanand Venkatasubbu, G.; Kumar, J.; Ramakrishnan, V.

2014-01-01

The pure hydroxyapatite (HAP) nanoparticles (NPs) have been synthesized by wet chemical precipitation method. Raman spectral measurements have been made for pure HAP, pure Polyethylene glycol (PEG) 6000 and PEG coated HAP in different mass ratios (sample 1, sample 2 and sample 3). The peaks observed in Raman spectrum of pure HAP and the XRD pattern have confirmed the formation of HAP NPs. Vibrational modes have been assigned for pure HAP and pure PEG 6000. The observed variation in peak position of Raman active vibrational modes of PEG in PEG coated HAP has been elucidated in this work, in terms of intermolecular interactions between PEG and HAP. Further these results suggest that the functionalization of nanoparticles may be independent of PEG mass.

Infrared (IR) photon-sensitive spectromicroscopy in a cryogenic environment

DOEpatents

Pereverzev, Sergey

2016-06-14

A system designed to suppress thermal radiation background and to allow IR single-photon sensitive spectromicroscopy of small samples by using both absorption, reflection, and emission/luminescence measurements. The system in one embodiment includes: a light source; a plurality of cold mirrors configured to direct light along a beam path; a cold or warm sample holder in the beam path; windows of sample holder (or whole sample holder) are transparent in a spectral region of interest, so they do not emit thermal radiation in the same spectral region of interest; a cold monochromator or other cold spectral device configured to direct a selected fraction of light onto a cold detector; a system of cold apertures and shields positioned along the beam path to prevent unwanted thermal radiation from arriving at the cold monochromator and/or the detector; a plurality of optical, IR and microwave filters positioned along the beam path and configured to adjust a spectral composition of light incident upon the sample under investigation and/or on the detector; a refrigerator configured to maintain the detector at a temperature below 1.0K; and an enclosure configured to: thermally insulate the light source, the plurality of mirrors, the sample holder, the cold monochromator and the refrigerator.

Photometric and Spectral Study of the Saturnian Satellites

NASA Technical Reports Server (NTRS)

Newman, Sarah F.

2005-01-01

Photometric and spectra analysis of data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) has yielded intriguing findings regarding the surface properties of several of the icy Saturnian satellites. Spectral cubes were obtained of these satellites with a wavelength distribution in the IR far more extensive than from any previous observations. Disk-integrated solar phase curves were constructed in several key IR wavelengths that are indicative of key properties of the surface of the body, such as macroscopic roughness, fluffiness (or the porosity of the surface), global albedo and scattering properties of surface particles. Polynomial fits to these phase curves indicate a linear albedo trend of the curvature of the phase functions. Rotational phase functions from Enceladus were found to exhibit a double-peaked sinusoidal curve, which shows larger amplitudes for bands corresponding to water ice and a linear amplitude-albedo trend. These functions indicate regions on the surface of the satellite of more recent geologic activity. In addition, recent images of Enceladus show tectonic features and an absence of impact craters on Southern latitudes which could be indicative of a younger surface. Investigations into the properties of these features using VIMS are underway.

Exploring the Full Range of Properties of Quasar Spectral Distributions

NASA Technical Reports Server (NTRS)

Wilkes, B.

1998-01-01

The aim of this work is to support our ISO, far-infrared (IR) observing program of quasars and active galaxies. We have obtained, as far as possible, complete spectral energy distributions (radio-X-ray) of the ISO sample in order to fully delineate the continuum shapes and to allow detailed modelling of that continuum. This includes: ground-based optical, near-IR and mm data, the spectral ranges closest to the ISO data, within 1-2 years of the ISO observations themselves. ISO was launched in Nov 1995 and is currently observing routinely. It has an estimated lifetime is 2 years. All near-IR and optical imaging and spectroscopy are now in hand and in the process of being reduced, mm data collection and proposal writing continues.

Impaired Insulin Signaling is Associated with Hepatic Mitochondrial Dysfunction in IR+/--IRS-1+/- Double Heterozygous (IR-IRS1dh) Mice.

PubMed

Franko, Andras; Kunze, Alexander; Böse, Marlen; von Kleist-Retzow, Jürgen-Christoph; Paulsson, Mats; Hartmann, Ursula; Wiesner, Rudolf J

2017-05-30

Mitochondria play a pivotal role in energy metabolism, but whether insulin signaling per se could regulate mitochondrial function has not been identified yet. To investigate whether mitochondrial function is regulated by insulin signaling, we analyzed muscle and liver of insulin receptor (IR) +/- -insulin receptor substrate-1 (IRS-1) +/- double heterozygous (IR-IRS1dh) mice, a well described model for insulin resistance. IR-IRS1dh mice were studied at the age of 6 and 12 months and glucose metabolism was determined by glucose and insulin tolerance tests. Mitochondrial enzyme activities, oxygen consumption, and membrane potential were assessed using spectrophotometric, respirometric, and proton motive force analysis, respectively. IR-IRS1dh mice showed elevated serum insulin levels. Hepatic mitochondrial oxygen consumption was reduced in IR-IRS1dh animals at 12 months of age. Furthermore, 6-month-old IR-IRS1dh mice demonstrated enhanced mitochondrial respiration in skeletal muscle, but a tendency of impaired glucose tolerance. On the other hand, 12-month-old IR-IRS1dh mice showed improved glucose tolerance, but normal muscle mitochondrial function. Our data revealed that deficiency in IR/IRS-1 resulted in normal or even elevated skeletal muscle, but impaired hepatic mitochondrial function, suggesting a direct cross-talk between insulin signaling and mitochondria in the liver.

Molecular oxygen adsorption and dissociation on Au12M clusters with M = Cu, Ag or Ir

NASA Astrophysics Data System (ADS)

Jiménez-Díaz, Laura M.; Pérez, Luis A.

2018-03-01

In this work, we present a density functional theory study of the structural and electronic properties of isolated neutral clusters of the type Au12M, with M = Cu, Ag, or Ir. On the other hand, there is experimental evidence that gold-silver, gold-copper and gold-iridium nanoparticles have an enhanced catalytic activity for the CO oxidation reaction. In order to address these phenomena, we also performed density functional calculations of the adsorption and dissociation of O2 on these nanoparticles. Moreover, to understand the effects of Cu, Ag, and Ir impurity atoms on the dissociation of O2, we also analyze this reaction in the corresponding pure gold cluster. The results indicate that the substitution of one gold atom in a Au13 cluster by Ag, Cu or Ir diminishes the activation energy barrier for the O2 dissociation by nearly 1 eV. This energy barrier is similar for Au12Ag and Au12Cu, whereas for Au12Ir is even lower. These results suggest that the addition of other transition metal atoms to gold nanoclusters can enhance their catalytic activity towards the CO oxidation reaction, independently of the effect that the substrate could have on supported nanoclusters.

New high spectral resolution spectrograph and mid-IR camera for the NASA Infrared Telescope Facility

NASA Astrophysics Data System (ADS)

Tokunaga, Alan T.; Bus, Schelte J.; Connelley, Michael; Rayner, John

2016-10-01

The NASA Infrared Telescope Facility (IRTF) is a 3.0 m infrared telescope located at an altitude of 4.2 km near the summit of Mauna Kea on the island of Hawaii. The IRTF was established by NASA to support planetary science missions. We show new observational capabilities resulting from the completion of iSHELL, a 1-5 μm echelle spectrograph with resolving power of 70,000 using a 0.375 arcsec slit. This instrument will be commissioned starting in August 2016. The spectral grasp of iSHELL is enormous due to the cross-dispersed design and use of a 2Kx2K HgCdTe array. Raw fits files will be publicly archived, allowing for more effective use of the large amount of spectral data that will be collected. The preliminary observing manual for iSHELL, containing the instrument description, observing procedures and estimates of sensitivity can be downloaded at http://irtfweb.ifa.hawaii.edu/~ishell/iSHELL_observing_manual.pdf. This manual and instrument description papers can be downloaded at http://bit.ly/28NFiMj. We are also working to restore to service our 8-25 μm camera, MIRSI. It will be upgraded with a closed cycle cooler that will eliminate the need for liquid helium and allow continuous use of MIRSI on the telescope. This will enable a wider range of Solar System studies at mid-IR wavelengths, with particular focus on thermal observations of NEOs. The MIRSI upgrade includes plans to integrate a visible CCD camera that will provide simultaneous imaging and guiding capabilities. This visible imager will utilize similar hardware and software as the MORIS system on SpeX. The MIRSI upgrade is being done in collaboration with David Trilling (NAU) and Joseph Hora (CfA). For further information on the IRTF and its instruments including visitor instruments, see: http:// irtfweb.ifa.hawaii.edu/. We gratefully acknowledge the support of NASA contract NNH14CK55B, NASA Science Mission Directorate, and NASA grant NNX15AF81G (Trilling, Hora) for the upgrade of MIRSI.

Spectral-kinetic characteristics of luminescence of pentaerythritol tetranitrate with inclusions of iron nanoparticles upon explosion induced by laser pulses

NASA Astrophysics Data System (ADS)

Aduev, B. P.; Nurmukhametov, D. R.; Belokurov, G. M.; Nelyubina, N. V.; Gudilin, A. V.

2017-03-01

Spectral-kinetic characteristics of luminescence of tetranitropentaeritrite with inclusions of iron nanoparticles upon an explosion induced by laser pulses are measured with high temporal resolution. It is shown that the luminescence occurring during exposure to the laser pulse is a result of initiating a chemical reaction in tetranitropentaeritrite and is chemiluminescence. The glow is presumably associated with the excited nitrogen dioxide, NO2, which is formed by the rupture of O-NO2 bond in the tetranitropentaeritrite molecule.

IR technology for enhanced force protection by AIM

NASA Astrophysics Data System (ADS)

Breiter, R.; Ihle, T.; Rode, W.; Wendler, J.; Rühlich, I.; Haiml, M.; Ziegler, J.

2008-04-01

In all recent missions our forces are faced with various types of asymmetric threads like snipers, IEDs, RPGs or MANPADS. 2 nd and 3 rd Gen IR technology is a backbone of modern force protection by providing situational awareness and accurate target engagement at day/night. 3 rd Gen sensors are developed for thread warning capabilities by use of spectral or spatial information. The progress on a dual-color IR module is discussed in a separate paper [1]. A 1024x256 SWIR array with flexure bearing compressor and pulse tube cold finger provides > 50,000h lifetime for space or airborne hyperspectral imaging in pushbroom geometry with 256 spectral channels for improved change detection and remote sensing of IEDs or chemical agents. Similar concepts are pursued in the LWIR with either spectroscopic imaging or a system of LWIR FPA combined with a cooled tunable Laser to do spectroscopy with stimulated absorption of specific wavelengths. AIM introduced the RangIR sight to match the requirements of sniper teams, AGLs and weapon stations, extending the outstanding optronic performance of the fielded HuntIR with position data of a target by a laser range finder (LRF), a 3 axis digital magnetic compass (DMC) and a ballistic computer for accurate engagement of remote targets. A version with flexure bearing cooler with >30,000h life time is being developed for continuous operation in e.g. gunfire detection systems. This paper gives an overview of AIM's technologies for enhanced force protection.

A Fast Hyperspectral Vector Radiative Transfer Model in UV to IR spectral bands

NASA Astrophysics Data System (ADS)

Ding, J.; Yang, P.; Sun, B.; Kattawar, G. W.; Platnick, S. E.; Meyer, K.; Wang, C.

2016-12-01

We develop a fast hyperspectral vector radiative transfer model with a spectral range from UV to IR with 5 nm resolutions. This model can simulate top of the atmosphere (TOA) diffuse radiance and polarized reflectance by considering gas absorption, Rayleigh scattering, and aerosol and cloud scattering. The absorption component considers several major atmospheric absorbers such as water vapor, CO2, O3, and O2 including both line and continuum absorptions. A regression-based method is used to parameterize the layer effective optical thickness for each gas, which substantially increases the computation efficiency for absorption while maintaining high accuracy. This method is over 500 times faster than the existing line-by-line method. The scattering component uses the successive order of scattering (SOS) method. For Rayleigh scattering, convergence is fast due to the small optical thickness of atmospheric gases. For cloud and aerosol layers, a small-angle approximation method is used in SOS calculations. The scattering process is divided into two parts, a forward part and a diffuse part. The scattering in the small-angle range in the forward direction is approximated as forward scattering. A cloud or aerosol layer is divided into thin layers. As the ray propagates through each thin layer, a portion diverges as diffuse radiation, while the remainder continues propagating in forward direction. The computed diffuse radiance is the sum of all of the diffuse parts. The small-angle approximation makes the SOS calculation converge rapidly even in a thick cloud layer.

Standardized cell samples for midIR technology development

NASA Astrophysics Data System (ADS)

Kastl, Lena; Rommel, Christina E.; Kemper, Björn; Schnekenburger, Jürgen

2015-03-01

The application of midIR spectroscopy towards human cell and tissue samples is impaired by the need for technical solutions and lacking sample standards for technology development. We here present the standardization of stable test samples for the continuous development and testing of novel optical system components. We have selected cell lines representing the major cellular skin constituents keratinocytes and fibroblasts (NIH-3T3, HaCaT). In addition, two skin cancer cell types (A-375 and SK-MEL-28 cells) were analyzed. Cells were seeded on CaF2 substrates and measured dried and under aqueous medium as well as fixated and unfixated. Several independent cell preparations were analyzed with an FTIR spectrometer in the wave number range from 1000 - 4000 cm-1. The obtained data demonstrate that fixed and dehydrated cells on CaF2 can be stored in pure ethanol for several weeks without significant losses in quality of the spectral properties. The established protocol of cell seeding on CaF2 substrates, chemical fixation, dehydration, storage under ethanol and air-drying is suitable for the production of reliable midIR standards. The retrieved spectra demonstrate that fixed cells on CaF2 can be prepared reproducibly; with stable midIR spectral properties over several weeks and properties mimicking reliable unfixed cells. Moreover, the fixated samples on CaF2 show clear differences in the cell type specific spectra that can be identified by principle component analysis. In summary, the standardized cell culture samples on CaF2 substrates are suitable for the development of a midIR device and the optimization of the specific midIR spectra.

H2O2-responsive molecularly engineered polymer nanoparticles as ischemia/reperfusion-targeted nanotherapeutic agents

NASA Astrophysics Data System (ADS)

Lee, Dongwon; Bae, Soochan; Hong, Donghyun; Lim, Hyungsuk; Yoon, Joo Heung; Hwang, On; Park, Seunggyu; Ke, Qingen; Khang, Gilson; Kang, Peter M.

2013-07-01

The main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury is the overproduction of reactive oxygen species (ROS). Hydrogen peroxide (H2O2), the most abundant form of ROS produced during I/R, causes inflammation, apoptosis and subsequent tissue damages. Here, we report H2O2-responsive antioxidant nanoparticles formulated from copolyoxalate containing vanillyl alcohol (VA) (PVAX) as a novel I/R-targeted nanotherapeutic agent. PVAX was designed to incorporate VA and H2O2-responsive peroxalate ester linkages covalently in its backbone. PVAX nanoparticles therefore degrade and release VA, which is able to reduce the generation of ROS, and exert anti-inflammatory and anti-apoptotic activity. In hind-limb I/R and liver I/R models in mice, PVAX nanoparticles specifically reacted with overproduced H2O2 and exerted highly potent anti-inflammatory and anti-apoptotic activities that reduced cellular damages. Therefore, PVAX nanoparticles have tremendous potential as nanotherapeutic agents for I/R injury and H2O2-associated diseases.

Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

NASA Astrophysics Data System (ADS)

Cristescu, R.; Visan, A.; Socol, G.; Surdu, A. V.; Oprea, A. E.; Grumezescu, A. M.; Chifiriuc, M. C.; Boehm, R. D.; Yamaleyeva, D.; Taylor, M.; Narayan, R. J.; Chrisey, D. B.

2016-06-01

The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF* excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

Size dependence of magneto-optical activity in silver nanoparticles with dimensions between 10 and 60 nm studied by MCD spectroscopy.

PubMed

Shiratsu, Taisuke; Yao, Hiroshi

2018-02-07

Size-dependent magneto-optical activity in Ag nanoparticles with dimensions from 10 to 60 nm is demonstrated with magnetic circular dichroism (MCD) spectroscopy. The Ag nanoparticles are prepared on the basis of a seeded-growth strategy using sodium citrate and/or tannic acid as reducing agents in aqueous solution. The obtained nanoparticles are roughly spherical, but those larger than ∼28 nm have a slight diversity of shapes with quasi-spherical polyhedrons. They exhibit a derivative-like MCD response in the localized surface plasmon resonance (LSPR) region, which originates from two circular modes of surface magnetoplasmons. With an increase in the nanoparticle diameter, the bisignated MCD signal is strongly distorted and weakened. Such a distortion for large-sized Ag nanoparticles can be phenomenologically simulated on the basis of both spectral inhomogeneity and MCD signal lobe asymmetry. Then the maximum value of MCD amplitude (MCD max ), which is obtained by normalization of the amplitude to the LSPR peak absorbance, first increases with increasing particle diameter and then decreases with a maximum for the 23 nm nanoparticle. Interestingly, the MCD max values are inversely correlated with the spectral bandwidth of LSPR extinction. This behaviour is discussed from a viewpoint of inhomogeneous effects of both spectral and size/shape distributions. We believe the present results will advance the design and application of optical devices based on magnetoplasmonics.

Radiative Properties of Thin Films of Common Dielectric Materials in the IR Spectral Range of 1.5-14.2 μm: Application to Infrared Imaging

NASA Astrophysics Data System (ADS)

Bañobre, Asahel; Marthi, Sita Rajyalaxmi; Ravindra, N. M.

2018-05-01

To measure, map and control temperature, imaging of materials in a thermal furnace routinely utilizes non-contact sensors, such as pyrometers. These pyrometers require a pre-knowledge of the radiative properties of materials in the desired infrared range of wavelengths. In this study, radiative properties of some commonly used thin films of dielectric materials are investigated within the infrared (IR) spectral range of 1.5-14.2 μm. Radiative properties of aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminum nitride (AlN) and silicon nitride (Si3N4) have been simulated and compared, utilizing a matrix method of representing the optical properties. The simulated results of the radiative properties show that Si3N4 is an excellent choice for the infrared radiation absorbing layer that is currently used in infrared uncooled detectors (microbolometers) because of its optical, mechanical and electrical properties. A case study of the radiative properties of an infrared uncooled microbolometer (Honeywell structure) is presented and discussed in the infrared spectral range of 8-14 μm. The results obtained serve as useful information for the design and fabrication of infrared imaging systems and components such as coatings, detectors, filters, lenses and waveguides.

Theoretical studies on photoelectron and IR spectral properties of Br2.-(H2O)n clusters.

PubMed

Pathak, A K; Mukherjee, T; Maity, D K

2007-07-28

We report vertical detachment energy (VDE) and IR spectra of Br2.-.(H2O)n clusters (n=1-8) based on first principles electronic structure calculations. Cluster structures and IR spectra are calculated at Becke's half-and-half hybrid exchange-correlation functional (BHHLYP) with a triple split valence basis function, 6-311++G(d,p). VDE for the hydrated clusters is calculated based on second order Moller-Plesset perturbation (MP2) theory with the same set of basis function. On full geometry optimization, it is observed that conformers having interwater hydrogen bonding among solvent water molecules are more stable than the structures having double or single hydrogen bonded structures between the anionic solute, Br2.-, and solvent water molecules. Moreover, a conformer having cyclic interwater hydrogen bonded network is predicted to be more stable for each size hydrated cluster. It is also noticed that up to four solvent H2O units can reside around the solute in a cyclic interwater hydrogen bonded network. The excess electron in these hydrated clusters is localized over the solute atoms. Weighted average VDE is calculated for each size (n) cluster based on statistical population of the conformers at 150 K. A linear relationship is obtained for VDE versus (n+3)(-1/3) and bulk VDE of Br2.- aqueous solution is calculated as 10.01 eV at MP2 level of theory. BHHLYP density functional is seen to make a systematic overestimation in VDE values by approximately 0.5 eV compared to MP2 data in all the hydrated clusters. It is observed that hydration increases VDE of bromine dimer anion system by approximately 6.4 eV. Calculated IR spectra show that the formation of Br2.--water clusters induces large shifts from the normal O-H stretching bands of isolated water keeping bending modes rather insensitive. Hydrated clusters, Br2.-.(H2O)n, show characteristic sharp features of O-H stretching bands of water in the small size clusters.

Theoretical studies on photoelectron and IR spectral properties of Br2.-(H2O)n clusters

NASA Astrophysics Data System (ADS)

Pathak, A. K.; Mukherjee, T.; Maity, D. K.

2007-07-01

We report vertical detachment energy (VDE) and IR spectra of Br2•-•(H2O)n clusters (n=1-8) based on first principles electronic structure calculations. Cluster structures and IR spectra are calculated at Becke's half-and-half hybrid exchange-correlation functional (BHHLYP) with a triple split valence basis function, 6-311++G(d,p). VDE for the hydrated clusters is calculated based on second order Moller-Plesset perturbation (MP2) theory with the same set of basis function. On full geometry optimization, it is observed that conformers having interwater hydrogen bonding among solvent water molecules are more stable than the structures having double or single hydrogen bonded structures between the anionic solute, Br2•-, and solvent water molecules. Moreover, a conformer having cyclic interwater hydrogen bonded network is predicted to be more stable for each size hydrated cluster. It is also noticed that up to four solvent H2O units can reside around the solute in a cyclic interwater hydrogen bonded network. The excess electron in these hydrated clusters is localized over the solute atoms. Weighted average VDE is calculated for each size (n) cluster based on statistical population of the conformers at 150K. A linear relationship is obtained for VDE versus (n+3)-1/3 and bulk VDE of Br2•- aqueous solution is calculated as 10.01eV at MP2 level of theory. BHHLYP density functional is seen to make a systematic overestimation in VDE values by ˜0.5eV compared to MP2 data in all the hydrated clusters. It is observed that hydration increases VDE of bromine dimer anion system by ˜6.4eV. Calculated IR spectra show that the formation of Br2•--water clusters induces large shifts from the normal O-H stretching bands of isolated water keeping bending modes rather insensitive. Hydrated clusters, Br2•-•(H2O)n, show characteristic sharp features of O-H stretching bands of water in the small size clusters.

Illumination analysis of LAPAN's IR micro bolometer

NASA Astrophysics Data System (ADS)

Bustanul, A.; Irwan, P.; Andi M., T.

2016-10-01

We have since 2 years ago been doing a research in term of an IR Micrometer Bolometer which aims to fulfill our office, LAPAN, desire to put it as one of payloads into LAPAN's next micro satellite project, either at LAPAN A4 or at LAPAN A5. Due to the lack of experience on the subject, everything had been initiated by spectral radiance analysis adjusted by catastrophes sources in Indonesia, mainly wild fire (forest fire) and active volcano. Based on the result of the appropriate spectral radiance wavelength, 3.8 - 4 μm, and field of view (FOV), we, then, went through the further analysis, optical analysis. Focusing in illumination matter, the process was done by using Zemax software. Optical pass Interference and Stray light were two things that become our concern throughout the work. They could also be an evaluation of the performance optimization of illumination analysis of our optical design. The results, graphs, show that our design performance is close diffraction limited and the image blur of the geometrical produced by Lapan's IR Micro Bolometer lenses is in the pixel area range. Therefore, our optical design performance is relatively good and will produce image with high quality. In this paper, the Illumination analysis and process of LAPAN's Infra Red (IR) Micro Bolometer is presented.

Demonstration of Bias-Controlled Algorithmic Tuning of Quantum Dots in a Well (DWELL) MidIR Detectors

DTIC Science & Technology

2009-06-01

additionally be utilized to cover a wider spectral range. In recent years, the long-wave IR ( LWIR : 8–12 m) region of the electromagnetic spectrum has been... LWIR region, and they can be sensed by their apparent temper- atures and spectral signatures in the LWIR . Currently, there are three main material...technologies for photonic IR photodetectors in the LWIR region. The HgCdTe (MCT) detector is the current state of the art due to its high responsivity

High-Resolution Light Transmission Spectroscopy of Nanoparticles in Real Time

NASA Astrophysics Data System (ADS)

Tanner, Carol; Sun, Nan; Deatsch, Alison; Li, Frank; Ruggiero, Steven

2017-04-01

As implemented here, Light Transmission Spectroscopy (LTS) is a high-resolution real-time technique for eliminating spectral noise and systematic effects in wide band spectroscopic measurements of nanoparticles. In this work, we combine LTS with spectral inversion for the purpose of characterizing the size, shape, and number of nanoparticles in solution. The apparatus employs a wide-band multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, and the wavelength dependent light detection system ranges from 200 to 1100 nm with <=1 nm resolution. With this system, nanoparticles ranging from 1 to 3000 nm diameters can be studied. The nanoparticles are typically suspended in pure water or water-based buffer solutions. For testing and calibration purposes, results are presented for nanoparticles composed of polystyrene and gold. Mie theory is used to model the total extinction cross-section, and spectral inversion is employed to obtain quantitative particle size distributions. Discussed are the precision, accuracy, resolution, and sensitivity of our results. The technique is quite versatile and can be applied to spectroscopic investigations where wideband, accurate, low-noise, real-time spectra are desired. University of Notre Dame Office of Research, College of Science, Department of Physics, and USDA.

Plant-mediated synthesis of silver nanoparticles using parsley ( Petroselinum crispum) leaf extract: spectral analysis of the particles and antibacterial study

NASA Astrophysics Data System (ADS)

Roy, Kaushik; Sarkar, C. K.; Ghosh, C. K.

2015-12-01

Synthesis of nanomaterials may involve various routes including physical, chemical and biological approaches. Here, the biological green route was chosen to prepare silver nanoparticles from silver salts to avoid the requirement of costly instruments and involvement of hazardous chemicals as well. To make the process clean and green, leaf extract of parsley ( Petroselinum crispum) was used to synthesize Ag nanoparticles at room temperature. The formation of Ag-nanoparticles was monitored by UV-Vis spectroscopy. The presence of silver in the sample and its crystalline nature were verified by X-ray diffraction (XRD) analysis. The size distribution profile and particle size in the suspension were manipulated from dynamic light scattering (DLS) pattern. The shape, size and morphology of the biogenic nanoparticles were studied using high resolution transmission electron microscope (TEM). Fourier transform infra-red spectroscopy was used to detect the biomolecules responsible for reduction of silver ions. These biogenic Ag-nanoparticles showed appreciable antibacterial efficacy against three bacteria— Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus.

Multifunctional organically modified silica nanoparticles for chemotherapy, adjuvant hyperthermia and near infrared imaging.

PubMed

Nagesetti, Abhignyan; McGoron, Anthony J

2016-11-01

We report a novel system of organically modified silica nanoparticles (Ormosil) capable of near infrared fluorescence and chemotherapy with adjuvant hyperthermia for image guided cancer therapy. Ormosil nanoparticles were loaded with a chemotherapeutic, Doxorubicin (DOX) and cyanine dye, IR820. Ormosil particles had a mean diameter of 51.2±2.4 nanometers and surface charge of -40.5±0.8mV. DOX was loaded onto Ormosil particles via physical adsorption (FDSIR820) or covalent linkage (CDSIR820) to the silanol groups on the Ormosil surface. Both formulations retained DOX and IR820 over a period of 2 days in aqueous buffer, though CDSIR820 retained more DOX (93.2%) compared to FDSIR820 (77.0%) nanoparticles. Exposure to near infrared laser triggered DOX release from CDSIR820. Uptake of nanoparticles was determined by deconvolution microscopy in ovarian carcinoma cells (Skov-3). CDSIR820 localized in the cell lysosomes whereas cells incubated with FDSIR820 showed DOX fluorescence from the nucleus indicating leakage of DOX from the nanoparticle matrix. FDSIR820 nanoparticles showed severe toxicity in Skov-3 cells whereas CDSIR820 particles had the same cytotoxicity profile as bare (No DOX and IR820) Ormosil particles. Furthermore, exposure of CDSIR820 nanoparticles to Near Infrared laser at 808 nanometers resulted in generation of heat (to 43°C from 37°C) and resulted in enhanced cell killing compared to Free DOX treatment. Bio-distribution studies showed that CDSIR820 nanoparticles were primarily present in the organs of Reticuloendothelial (RES) system. Copyright © 2016 Elsevier B.V. All rights reserved.

External-Cavity Quantum Cascade Laser Spectroscopy for Mid-IR Transmission Measurements of Proteins in Aqueous Solution.

PubMed

Alcaráz, Mirta R; Schwaighofer, Andreas; Kristament, Christian; Ramer, Georg; Brandstetter, Markus; Goicoechea, Héctor; Lendl, Bernhard

2015-07-07

In this work, we report mid-IR transmission measurements of the protein amide I band in aqueous solution at large optical paths. A tunable external-cavity quantum cascade laser (EC-QCL) operated in pulsed mode at room temperature allowed one to apply a path length of up to 38 μm, which is four times larger than that applicable with conventional FT-IR spectrometers. To minimize temperature-induced variations caused by background absorption of the ν2-vibration of water (HOH-bending) overlapping with the amide I region, a highly stable temperature control unit with relative temperature stability within 0.005 °C was developed. An advanced data processing protocol was established to overcome fluctuations in the fine structure of the emission curve that are inherent to the employed EC-QCL due to its mechanical instabilities. To allow for wavenumber accuracy, a spectral calibration method has been elaborated to reference the acquired IR spectra to the absolute positions of the water vapor absorption bands. Employing this setup, characteristic spectral features of five well-studied proteins exhibiting different secondary structures could be measured at concentrations as low as 2.5 mg mL(-1). This concentration range could previously only be accessed by IR measurements in D2O. Mathematical evaluation of the spectral overlap and comparison of second derivative spectra confirm excellent agreement of the QCL transmission measurements with protein spectra acquired by FT-IR spectroscopy. This proves the potential of the applied setup to monitor secondary structure changes of proteins in aqueous solution at extended optical path lengths, which allow experiments in flow through configuration.

Sensitivity Study of IROE Cloud Retrievals Using VIIRS M-Bands and Combined VIIRS/CrIS IR Observations

NASA Astrophysics Data System (ADS)

Wang, C.; Platnick, S. E.; Meyer, K.; Ackerman, S. A.; Holz, R.; Heidinger, A.

2017-12-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi-NPP spacecraft is considered as the next generation of instrument providing operational moderate resolution imaging capabilities after the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. However, cloud-top property (CTP) retrieval algorithms designed for the two instruments cannot be identical because of the absence of CO2 bands on VIIRS. In this study, we conduct a comprehensive sensitivity study of cloud retrievals utilizing a IR-Optimal Estimation (IROE) based algorithm. With a fast IR radiative transfer model, the IROE simultaneously retrieves cloud-top height (CTH), cloud optical thickness (COT), cloud effective radius (CER) and corresponding uncertainties using a set of IR bands. Three retrieval runs are implemented for this sensitivity study: retrievals using 1) three native VIIRS M-Bands at 750m resolution (8.5-, 11-, and 12-μm), 2) three native VIIRS M-Bands with spectrally integrated CO2 bands from the Cross-Track Infrared Sounder (CrIS), and 3) six MODIS IR bands (8.5-, 11-, 12-, 13.3-, 13.6-, and 13.9-μm). We select a few collocated MODIS and VIIRS granules for pixel-level comparison. Furthermore, aggregated daily and monthly cloud properties from the three runs are also compared. It shows that, the combined VIIRS/CrIS run agrees well with the MODIS-only run except for pixels near cloud edges. The VIIRS-only run is close to its counterparts when clouds are optically thick. However, for optically thin clouds, the VIIRS-only run can be readily influenced by the initial guess. Large discrepancies and uncertainties can be found for optically thin clouds from the VIIRS-only run.

Application of IRS-1D data in water erosion features detection (case study: Nour roud catchment, Iran).

PubMed

Solaimani, K; Amri, M A Hadian

2008-08-01

The aim of this study was capability of Indian Remote Sensing (IRS) data of 1D to detecting erosion features which were created from run-off. In this study, ability of PAN digital data of IRS-1D satellite was evaluated for extraction of erosion features in Nour-roud catchment located in Mazandaran province, Iran, using GIS techniques. Research method has based on supervised digital classification, using MLC algorithm and also visual interpretation, using PMU analysis and then these were evaluated and compared. Results indicated that opposite of digital classification, with overall accuracy 40.02% and kappa coefficient 31.35%, due to low spectral resolution; visual interpretation and classification, due to high spatial resolution (5.8 m), prepared classifying erosion features from this data, so that these features corresponded with the lithology, slope and hydrograph lines using GIS, so closely that one can consider their boundaries overlapped. Also field control showed that this data is relatively fit for using this method in investigation of erosion features and specially, can be applied to identify large erosion features.

Raman scattering studies on PEG functionalized hydroxyapatite nanoparticles.

PubMed

Yamini, D; Devanand Venkatasubbu, G; Kumar, J; Ramakrishnan, V

2014-01-03

The pure hydroxyapatite (HAP) nanoparticles (NPs) have been synthesized by wet chemical precipitation method. Raman spectral measurements have been made for pure HAP, pure Polyethylene glycol (PEG) 6000 and PEG coated HAP in different mass ratios (sample 1, sample 2 and sample 3). The peaks observed in Raman spectrum of pure HAP and the XRD pattern have confirmed the formation of HAP NPs. Vibrational modes have been assigned for pure HAP and pure PEG 6000. The observed variation in peak position of Raman active vibrational modes of PEG in PEG coated HAP has been elucidated in this work, in terms of intermolecular interactions between PEG and HAP. Further these results suggest that the functionalization of nanoparticles may be independent of PEG mass. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral studies of 2-pyrazoline derivatives: structural elucidation through single crystal XRD and DFT calculations.

PubMed

Chinnaraja, D; Rajalakshmi, R; Srinivasan, T; Velmurugan, D; Jayabharathi, J

2014-04-24

A series of biologically active N-thiocarbamoyl pyrazoline derivatives have been synthesized using anhydrous potassium carbonate as the catalyst. All the synthesized compounds were characterized by FT-IR, (1)H NMR, (13)C NMR spectral studies, LCMS, CHN Analysis and X-ray diffraction analysis (compound 7). In order to supplement the XRD parameters, molecular modelling was carried out by Gaussian 03W. From the optimized structure, the energy, dipolemoment and HOMO-LUMO energies of all the systems were calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy

NASA Astrophysics Data System (ADS)

Qu, Lei; Chen, Jian-bo; Zhang, Gui-Jun; Sun, Su-qin; Zheng, Jing

2017-03-01

As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p = 0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR.

Diagnosis of Breast Cancer Based on FT-IR Spectroscopy

NASA Astrophysics Data System (ADS)

Venkatachalam, P.; Rao, L. Lakshmana; Kumar, N. Krishna; Jose, Anupama; Nazeer, Shaiju S.

2008-11-01

Breast cancer is one of the most important malignant forms of cancer and a great threat to life for women. In the present study, the spectral characteristics of human breast tissues in normal and cancerous state have been investigated by Fourier transform infrared (FT-IR) absorption spectroscopy in the spectral region from 4000 to 400 cm-1. Several spectral differences were detected in the frequency regions N-H stretching, C-H vibrations, amide bands and 900-1300 cm-1. The ratio of intensities of the bands of A3300/A3015 & A1650/A1550, A2924/A2853, A1080/A1236, A1204/A1650, A1055/A1467 and A1045/A1467 provide conformational changes of protein, lipids, nucleic acids, collagen, carbohydrates and glycogen respectively in the human breast tissues. There are obvious differences in the spectral features between normal and cancerous tissues because of changes in molecular compositions and structures that accompany the transformation from a normal to a cancerous state. The differences suggest that the spectral information are useful for the diagnosis of breast cancer and may serve as a basis for conformational changes in tissue components during carcinogenesis.

Multispectral near-IR reflectance imaging of simulated early occlusal lesions: Variation of lesion contrast with lesion depth and severity

PubMed Central

Simon, Jacob C.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

2014-01-01

Background and Objectives Early demineralization appears with high contrast at near-IR wavelengths due to a ten to twenty fold difference in the magnitude of light scattering between sound and demineralized enamel. Water absorption in the near-IR has a significant effect on the lesion contrast and the highest contrast has been measured in spectral regions with higher water absorption. The purpose of this study was to determine how the lesion contrast changes with lesion severity and depth for different spectral regions in the near-IR and compare that range of contrast with visible reflectance and fluorescence. Materials and Methods Forty-four human molars were used in this in vitro study. Teeth were painted with an acid-resistant varnish, leaving a 4×4 mm window on the occlusal surface of each tooth exposed for demineralization. Artificial lesions were produced in the unprotected windows after 12–48 hr exposure to a demineralizing solution at pH-4.5. Near-IR reflectance images were acquired over several near-IR spectral distributions, visible light reflectance, and fluorescence with 405-nm excitation and detection at wavelengths greater than 500-nm. Crossed polarizers were used for reflectance measurements to reduce interference from specular reflectance. Cross polarization optical coherence tomography (CP-OCT) was used to non-destructively assess the depth and severity of demineralization in each sample window. Matching two dimensional CP-OCT images of the lesion depth and integrated reflectivity were compared with the reflectance and fluorescence images to determine how accurately the variation in the lesion contrast represents the variation in the lesion severity. Results Artificial lesions appear more uniform on tooth surfaces exposed to an acid challenge at visible wavelengths than they do in the near-IR. Measurements of the lesion depth and severity using CP-OCT show that the lesion severity varies markedly across the sample windows and that the lesion

Multiband optical-IR variability of the blazar PKS 0537-441

NASA Astrophysics Data System (ADS)

Li, Xiao-Pan; Wang, Li-Sha; Yang, Cheng; Yang, Hai-yan; Zhou, Li; Xu, Guang-Yang; Shan, Yu-Qiong; Liu, Jie; Luo, Yu-Hui; Zhang, Li

2018-06-01

We have reconsidered the simultaneous and homogeneous optical-IR light curves and the corresponding spectral indices curve of the blazar PKS 0537-441 from January 2011 to May 2015. All the curves show significant fluctuations on various timescales, and the flux variations seem to be more pronounced towards the IR bands. The relation between average fluxes and spectral indices reveals the existence of redder-when-brighter (RWB) and bluer-when-brighter (BWB) trends at different flux levels, along with a long-term achromatic trend and a mild RWB trend on short-term timescales. Cross-correlation analyses present an energy-dependent time delay that the lower-frequency variations follow higher-frequency ones by a few weeks and a hysteresis pattern between spectra and fluxes. Our analysis reveals some potential coherence between low-energy-peaked BL Lacs (LBLs) and FSRQs, and indicates that the observed flux variability and spectral changes could be due to the superposition of a dominant jet emission, an underlying thermal contribution from a more slowly varying disk and/or other geometric effects under the shock-in-jet scenario.

Studying the silver nanoparticles influence on thermodynamic behavior and antimicrobial activities of novel amide Gemini cationic surfactants.

PubMed

Shaban, Samy M; Abd-Elaal, Ali A

2017-07-01

Three novels amide Gemini cationic surfactants with various alkyl chains and their silver nanohybrid with silver nanoparticles were synthesized and a confirmation study for surfactant and their nanoparticles formation has been established using IR, 1 HNMR, TEM and UV-Vis spectroscopy. The surface-active properties of these surfactants and their nanoform were investigated through surface tension and electrical conductivity measurements and a comparative study has been established. The thermodynamic parameters of micellization and adsorption were assessed at temperatures range from 25 to 65°C. The effect of silver particles on the surface behavior of the synthesized surfactant has been discussed. The aggregation behavior of silver nanoparticles with these synthesized Gemini surfactants in water were investigated using dynamic light scattering and transmission electron microscopy. Furthermore, the antimicrobial activities of these synthesized amide Gemini surfactants and their nanostructure with silver against both Gram positive and Gram negative bacteria were also investigated. Copyright © 2017 Elsevier B.V. All rights reserved.

Fiber Delivery of mid-IR lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kriesel, J.M.; Gat, N.; Bernacki, Bruce E.

2011-08-24

Fiber optics for the visible to near infrared (NIR) wavelength regimes (i.e. = 0.42 {mu}m) have proven to be extremely useful for a myriad of applications such as telecommunications, illumination, and sensors because they enable convenient, compact, and remote delivery of laser beams. Similarly, there is a need for fiber optics operating at longer wavelengths. For example, systems operating in the mid-IR regime (i.e., = 314 {mu}m) are being developed to detect trace molecular species with far-reaching applications, such as detecting explosives on surfaces, pollutants in the environment, and biomarkers in the breath of a patient. Furthermore, with the increasingmore » availability of quantum cascade lasers (QCLs) which are semiconductor lasers that operate in the mid-IR regime additional uses are rapidly being developed. Here, we describe the development of hollow-core fibers for delivery of high-quality mid-IR laser beams across a broad spectral range.« less

MicrOmega IR: a new infrared hyperspectral imaging microscope or in situ analysis

NASA Astrophysics Data System (ADS)

Vaitua, Leroi; Bibring, Jean-Pierre; Berthé, Michel

2017-11-01

MicrOmega IR is an ultra miniaturized Near Infrared hyperspectral microscope for in situ analysis of samples. It is designed to be implemented on board space planetary vehicles (lander and/or rovers). It acquires images of samples typically some 5 mm in width with a spatial sampling of 20 μm. On each pixel, MicrOmega acquires the spectrum in the spectral range 0.9 - 2.6 μm, with a possibility to extend the sensibility up to 4 μm. The spectrum will be measured in up to 300 contiguous spectral channels (600 in the extended range): given the diagnostic spectral features present in this domain, it provides the composition of each spatially resolved constituent. MicrOmega has thus the potential to identify: minerals, such as pyroxene and olivine, ferric oxides, hydrated phases such as phyllosilicates, sulfates and carbonates, ices and organics. The composition of the various phases within a given sample is a critical record of its formation and evolution. Coupled to the mapping information, it provides unique clues to describe the history of the parent body. In particular, the capability to identify hydrated grains and to characterize their adjacent phases has a huge potential in the search for potential bio-relics in Martian samples. This purely non destructive characterization enables further analyses (e.g. through mass spectrometry) to be performed, and/or to contribute to sample selection to return to Earth. MicrOmega IR is coupled to a visible microscope: MicrOmega VIS. Thus, the MicrOmega instrument is developed by an international consortium: IAS (Orsay, France), LESIA (Meudon, France), CBM (Orléans, France), University Of Bern (Bern, Switzerland), IKI (Moscow, Russia). This instrument (MicrOmega IR, MicrOmega VIS and the electronics) is selected for the ESA Exomars mission (launch scheduled for 2013). MicrOmega IR will be used in a reduced spectral range (0.9 - 2.6 μm), due to power, mass and thermal constraints: however, most minerals and other

Generation of drugs coated iron nanoparticles through high energy ball milling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radhika Devi, A.; Murty, B. S.; Chelvane, J. A.

The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

Synthesis and characterization of PEG-P(MAA-SS-VCL) nanoparticles

NASA Astrophysics Data System (ADS)

Yu, L. L.; Yang, K.; Mu, R. H.; Zhang, N.; Su, L.

2016-07-01

The PEG-P(MAA-SS-VCL) nanoparticles were obtained using disulfide containing dimethacrylate (SS) as cross-linking agent, using polyethylene glycol methyl acrylate (PEGMA), N-Vinyl-ε-caprolactam (VCL), and methacrylic acid (MAA) as monomers via homogeneous polymerization in aqueous. The PEG-P(MAA-SS-VCL) nanoparticles were characterized by FT-IR and TGA. The particle size and morphology variation in different environments were detected by dynamic light scattering (DLS) and scanning electron microscopy (SEM). It is the very method that PEG-P(MAA-SS-VCL) nanoparticles can be obtained in this study.

FT-IR and DFT study of lemon peel

NASA Astrophysics Data System (ADS)

Berezin, K. V.; Likhter, A. M.; Shagautdinova, I. T.; Chernavina, M. L.; Novoselova, A. V.

2017-03-01

Experimental FT-IR spectra of lemon peel are registered in the 650 - 3800 cm-1 range. The influence of peel artificial and natural dehydration on its vibrational spectrum is studied. The colored outer surface of lemon peel is proved not to have a significant impact on FT-IR spectrum. It is determined that only dehydration processes affect the FT-IR vibrational spectrum of the peel when a lemon is stored for 28 days under natural laboratory conditions. Polymer molecule models for dietary fibers, such as cellulose, hemicellulose, pectin, lignin, as well as hesperidin - flavonoid glycoside, and free moisture cluster are developed within the framework of DFT/B3LYP/6-31G(d) theoretical method. By implementing supramolecular approach, modeling of the vibrational FT-IR spectrum of lemon peel is carried out and its detailed theoretical interpretation is presented.

FT-IR Spectroscopic Analysis of Normal and Malignant Human Oral Tissues

NASA Astrophysics Data System (ADS)

Krishnakumar, N.; Madhavan, R. Nirmal; Sumesh, P.; Palaniappan, Pl. Rm.; Venkatachalam, P.; Ramachandran, C. R.

2008-11-01

FT-IR spectroscopy has been used to explore the changes in the vibrational bands of normal and oral squamous cell carcinoma (OSCC) tissues in the region 4000-400 cm-1. Significant changes in the spectral features were observed. The spectral changes were the results of characteristics structural alterations at the molecular level in the malignant tissues. These alterations include structural changes of proteins and possible increase of its content, an increase in the nucleic-to-cytoplasm ratio, an increase in the relative amount of DNA, an increase in the rate of phosphorylation process induced by carcinogenesis, a loss of hydrogen bonding of the C-OH groups in the amino acid residues of proteins, a decrease in the relative amount of lipids compared to normal epithelial oral tissues. The results of the present study demonstrate that the FT-IR technique has the feasibility of discriminating malignant from normal tissues and other pathological states in a short period of time and may detect malignant transformation earlier than the standard histological examination stage.

Spectral analysis of the structure of ultradispersed diamonds

NASA Astrophysics Data System (ADS)

Uglov, V. V.; Shimanski, V. I.; Rusalsky, D. P.; Samtsov, M. P.

2008-07-01

The structure of ultradispersed diamonds (UDD) is studied by spectral methods. The presence of diamond crystal phase in the UDD is found based on x-ray analysis and Raman spectra. The Raman spectra also show sp2-and sp3-hybridized carbon. Analysis of IR absorption spectra suggests that the composition of functional groups present in the particles changes during the treatment.

A Feasibility Study on the Geophysical Response to Nanoparticles in the Subsurface

EPA Science Inventory

The research presented herein aims to determine if a spectral induced polarization (SIP) response exists due to nanoparticles in a saturated sand matrix. If a SIP response is realized in such an experimental setting, then it is feasible that SIP may be capable of delineating nano...

Improvement of polypyrrole nanowire devices by plasmonic space charge generation: high photocurrent and wide spectral response by Ag nanoparticle decoration.

PubMed

Lee, S-H; Bae, J; Lee, S W; Jang, J-W

2015-11-07

In this study, improvement of the opto-electronic properties of non-single crystallized nanowire devices with space charges generated by localized surface plasmon resonance (LSPR) is demonstrated. The photocurrent and spectral response of single polypyrrole (PPy) nanowire (NW) devices are increased by electrostatically attached Ag nanoparticles (Ag NPs). To take advantage of plasmon-exciton coupling in the photocurrent of the device, 80 nm of Ag NPs (454 nm = λmax) were chosen for matching the maximum absorption with PPy NWs (442 nm = λmax). The photocurrent density is remarkably improved, up to 25.3 times (2530%), by the Ag NP decoration onto the PPy NW (PPyAgNPs NW) under blue light (λ = 425-475 nm) illumination. In addition, the PPyAgNPs NW shows a photocurrent decay time twice that of PPy NW, as well as an improved spectral response of the photocurrent. The improved photocurrent efficiency, decay time, and spectral response resulted from the space charges generated by the LSPR of Ag NPs. Furthermore, the increasing exponent (m) of the photocurrent (JPC ∼ V(m)) and finite-differential time domain (FDTD) simulation straightforwardly indicate relatively large plasmonic space charge generation under blue light illumination. These results prove that the performance of non-single crystallized polymer nanowire devices can also be improved by plasmonic enhancement.

Interactions of Fluorescein Dye with Spherical and Star Shaped Gold Nanoparticles.

PubMed

Pal, Gopa Dutta; Paul, Somnath; Bardhan, Munmun; Ganguly, Tapan

2018-04-01

UV-vis absorption, FT-IR, steady state fluorescence and fluorescence lifetime measurements were made on Fluorescein dye (Fl dye) molecules in presence of gold nanoparticles of different morphologies: spherical gold nanoparticles (GNP) and star shaped gold nanoparticles (GNS). The experimental observations demonstrate that Fl dye molecules form dimers when adsorbed on nanosurface of spherical gold particles. On the other hand possibly due to lack of adsorption on the surface of GNS the dye molecules were unable to form dimers. The projected tips on the surface of GNS may possibly hinder the dyes to adsorb on the surface of this nanoparticle. From the spectral analysis and measurements of thermodynamic parameters it is inferred that two different types of ground state interactions occur between Fl-dye-GNP and Fl dye-GNS systems. Both the observed negative values of the thermodynamic parameters ΔH and ΔS in the case of the former system predict the possibility of occurrences of hydrogen bonding interactions between two neighboring Fl dye molecules when adsorbed on the nanosurface of GNP. On the other hand in Fl dye-GNS system electrostatic interactions appear to occur, as evidenced from negative ΔH and positive value of ΔS, between the positive charges residing on the tips of the nanoparticles and anionic form of Fl dye. It has been concluded that as the adsorption of organic dyes on solid surfaces is prerequisite for the degradation of dye pollutants, the present experimental observations demonstrate that GNP could be used as a better candidate than GNS in degradation mechanism of the xanthenes dyes.

Spectral dependence of the main parameters of ITE silicon avalanche photodiodes

NASA Astrophysics Data System (ADS)

Wegrzecka, Iwona; Grynglas, Maria; Wegrzecki, Maciej

2001-08-01

New applications for avalanche photodiodes (APDs) as in systems using visible radiation, have prompted the need for the evaluation of detection properties of ITE APDs in the 400 divided by 700 nm spectral range. The paper presents the method and result of studies on the spectral dependence of the gain, dark and noise currents, sensitivity and excess noise factor of ITE APDs. The studies have shown that ITE APDs optimized for the near IR radiation can be effectively applied in the detection of radiation above the 500 nm wavelength.

Orientation of N-(1-(2-chlorophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide on silver nanoparticles: SERS studies.

PubMed

Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Meenakumari, V; Milton Franklin Benial, A

2014-10-15

In the present study, the silver nanoparticles were synthesized using a solution combustion method with urea as fuel. The prepared silver nanoparticles show an FCC crystalline structure with particle size of 59nm. FESEM image shows the prepared silver is a rod like structure. The surface-enhanced Raman scattering (SERS) spectrum indicates that the N-(1-(2-chlorophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide (CS) molecule adsorbed on the silver nanoparticles. The spectral analysis reveals that the sulfonamide is adsorbed by tilted orientation on the silver surface. The Hatree Fock calculations were also performed to predict the vibrational motions of CS. This present investigation has been a model system to deduce the interaction of drugs with DNA. Copyright © 2014 Elsevier B.V. All rights reserved.

Complementarity of UV and IR differential absorption lidar for global measurements of atmospheric species

NASA Technical Reports Server (NTRS)

Megie, G.; Menzies, R. T.

1980-01-01

An analysis of the potential capabilities of a spectrally diversified DIAL technique for monitoring atmospheric species is presented assuming operation from an earth-orbiting platform. Emphasis is given to the measurement accuracies and spatial and temporal resolutions required to meet present atmospheric science objectives. The discussion points out advantages of spectral diversity to perform comprehensive studies of the atmosphere; in general it is shown that IR systems have an advantage in lower atmospheric measurements, while UV systems are superior for middle and upper atmospheric measurements.

Synthesis and spectroscopic study of CdS nanoparticles using hydrothermal method

NASA Astrophysics Data System (ADS)

AL-Mamoori, Mohammed H. K.; Mahdi, Dunia K.; Al-Shrefi, Saif M.

2018-05-01

In this work, cadmium sulfide nanoparticles (powder) with diameter 50.8 nm was prepared using hydrothermal method. The structural and optical properties of CdS nanoparticles was studied by X-ray diffraction, FESEM, EDS, FTIR, UV-Diffuse Reflectance spectroscopy and Photoluminance spectrum. X-ray diffraction reveal the formation the purity of prepared phase of CdS particles with hexagonal wurtzite structure with particle size 31.8nm by using sheerer equation. The energy dispersion scattering (EDS) examination explains that the sample is composed of a large amount of Cd and S which are exactly CdS nanoparticles and there is a very small trace of (Zn) and (O) element observed because of there is a small pollutions in the measurement place of samples. FESEM shows the spherical shape of nanoparticles with around 50.8 nm diameter. The optical absorption spectral study identified the red shift of the sample in comparison to bulk ZnO in three dimensions. Photoluminance spectrum (PL) at room temperature showed that there are two luminescence peaks at 433.14 nm and 518.21nm. Samples demonstrate a sharp emission band at around 433.18 nm, which is attributed to the typical exciton luminescence. The broad band at 518.21nm which were attributed to the trapped luminescence. The green emission band at 518.21 nm was associated with the emission due to electronic transition from the conduction band to an accepter level due to interstitial sulphur ion.

Impaired Insulin Signaling is Associated with Hepatic Mitochondrial Dysfunction in IR+/−-IRS-1+/− Double Heterozygous (IR-IRS1dh) Mice

PubMed Central

Franko, Andras; Kunze, Alexander; Böse, Marlen; von Kleist-Retzow, Jürgen-Christoph; Paulsson, Mats; Hartmann, Ursula; Wiesner, Rudolf J.

2017-01-01

Mitochondria play a pivotal role in energy metabolism, but whether insulin signaling per se could regulate mitochondrial function has not been identified yet. To investigate whether mitochondrial function is regulated by insulin signaling, we analyzed muscle and liver of insulin receptor (IR)+/−-insulin receptor substrate-1 (IRS-1)+/− double heterozygous (IR-IRS1dh) mice, a well described model for insulin resistance. IR-IRS1dh mice were studied at the age of 6 and 12 months and glucose metabolism was determined by glucose and insulin tolerance tests. Mitochondrial enzyme activities, oxygen consumption, and membrane potential were assessed using spectrophotometric, respirometric, and proton motive force analysis, respectively. IR-IRS1dh mice showed elevated serum insulin levels. Hepatic mitochondrial oxygen consumption was reduced in IR-IRS1dh animals at 12 months of age. Furthermore, 6-month-old IR-IRS1dh mice demonstrated enhanced mitochondrial respiration in skeletal muscle, but a tendency of impaired glucose tolerance. On the other hand, 12-month-old IR-IRS1dh mice showed improved glucose tolerance, but normal muscle mitochondrial function. Our data revealed that deficiency in IR/IRS-1 resulted in normal or even elevated skeletal muscle, but impaired hepatic mitochondrial function, suggesting a direct cross-talk between insulin signaling and mitochondria in the liver. PMID:28556799

RESOLVING THE ACTIVE GALACTIC NUCLEUS AND HOST EMISSION IN THE MID-INFRARED USING A MODEL-INDEPENDENT SPECTRAL DECOMPOSITION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernán-Caballero, Antonio; Alonso-Herrero, Almudena; Hatziminaoglou, Evanthia

2015-04-20

We present results on the spectral decomposition of 118 Spitzer Infrared Spectrograph (IRS) spectra from local active galactic nuclei (AGNs) using a large set of Spitzer/IRS spectra as templates. The templates are themselves IRS spectra from extreme cases where a single physical component (stellar, interstellar, or AGN) completely dominates the integrated mid-infrared emission. We show that a linear combination of one template for each physical component reproduces the observed IRS spectra of AGN hosts with unprecedented fidelity for a template fitting method with no need to model extinction separately. We use full probability distribution functions to estimate expectation values andmore » uncertainties for observables, and find that the decomposition results are robust against degeneracies. Furthermore, we compare the AGN spectra derived from the spectral decomposition with sub-arcsecond resolution nuclear photometry and spectroscopy from ground-based observations. We find that the AGN component derived from the decomposition closely matches the nuclear spectrum with a 1σ dispersion of 0.12 dex in luminosity and typical uncertainties of ∼0.19 in the spectral index and ∼0.1 in the silicate strength. We conclude that the emission from the host galaxy can be reliably removed from the IRS spectra of AGNs. This allows for unbiased studies of the AGN emission in intermediate- and high-redshift galaxies—currently inaccesible to ground-based observations—with archival Spitzer/IRS data and in the future with the Mid-InfraRed Instrument of the James Webb Space Telescope. The decomposition code and templates are available at http://denebola.org/ahc/deblendIRS.« less

IR reflectance spectroscopy of carbon dioxide clathrate hydrates. Implications for Saturn's icy moons.

NASA Astrophysics Data System (ADS)

Oancea, A.; Grasset, O.; Le Menn, E.; Bezacier, L.; Bollengier, O.; Le Mouélic, S.; Tobie, G.

2012-04-01

A CO2 spectral band was discovered by VIMS on the Saturn's satellites Dione, Hyperion, Iapetus and Phoebe [1]. The band position on the three first satellites corresponds to CO2 trapped in a complex material, but no indication exists whether this latter is water ice or some mineral or complex organic compound [1]. On Phoebe, the CO2 spectral band is consistent with solid CO2 or CO2 molecules trapped in the small cages of a clathrate hydrate structure [2]. It is thought that clathrate hydrates could play a significant role in the chemistry of the solar nebula [3] and in the physical evolution of astrophysical objects [4]. But so far, no clathrate hydrate structure has been observed in astrophysical environments. Moreover, identification of molecules trapped in a clathrate hydrate structure is extremely difficult because of the strong IR vibration modes of the water ice matrix. In this work, experimental IR reflectance spectra for CO2 clathrate hydrates are studied on grains and films. Clathrates are synthesized in a high pressure autoclave at low temperatures. IR spectral analysis is made with a low pressure and low temperature cryostat. These experimental conditions - 80 < T < 110 K, P~10-5 bar - are relevant to icy moons' surfaces. We have observed that the IR reflectance, in the spectral region (3 - 5 μm) characterized by H2O and CO2 high absorption coefficients, is strongly dependent on physical (size, surface) and optical (n and k) properties of the samples. The impact of these parameters on the CO2 clathrate IR reflectance spectrum will be presented. A comparison between the absorption bands of CO2 clathrate hydrates obtained in our lab and CO2 absorption bands as detected by VIMS on the icy satellites of Saturn will be shown. This experimental work confirms that VIMS data are not consistent with the presence of structure I CO2 clathrate hydrates on the surface of the icy moons. Possibility of having metastable structure II still remains unsolved and will be

IR and Raman spectra of nitroanthracene isomers: substitional effects based on density functional theory study.

PubMed

Alparone, Andrea; Librando, Vito

2012-04-01

Structure, IR and Raman spectra of 1-, 2- and 9-nitroanthracene isomers (1-NA, 2-NA and 9-NA) were calculated and analyzed through density functional theory computations using the B3LYP functional with the 6-311+G** basis set. Steric and π-conjugative effects determine the characteristic ONCC dihedral angles, which vary from 0° (2-NA) to 28-29° (1-NA) and 59° (9-NA), influencing the relative order of stability along the series 9-NA<1-NA<2-NA. The spectral regions at wavenumber values>3000 cm(-1) and <1000 cm(-1) little depend on the substituent position. The Raman and IR intensity values of the characteristic symmetric nitro group stretching transition, appearing between 1310 and 1345 cm(-1), are rather sensitive to the position of the substituent, decreasing regularly on passing from the planar to the NO2-rotated isomers (9-NA<1-NA<2-NA). In the medium-energy spectral region (1000-1700 cm(-1)), the number and the relative position of the strongest Raman bands are of potential utility to discriminate the NA isomers. Structural and spectroscopic results suggest that the unknown mutagenic activity of 1-NA is expected to be between that of 9-NA and 2-NA. Copyright © 2011 Elsevier B.V. All rights reserved.

Plasmonic and silicon spherical nanoparticle antireflective coatings

NASA Astrophysics Data System (ADS)

Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

2016-03-01

Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

Plasmonic and silicon spherical nanoparticle antireflective coatings

PubMed Central

Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

2016-01-01

Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes. PMID:26926602

The Jet-Cooled High-Resolution IR Spectrum of Formic Acid Cyclic Dimer

NASA Astrophysics Data System (ADS)

Goubet, Manuel; Bteich, Sabath; Huet, Therese R.; Pirali, Olivier; Asselin, Pierre; Soulard, Pascale; Jabri, Atef; Roy, P.; Georges, Robert

2017-06-01

As the simplest carboxylic acid, formic acid (FA) is an excellent model molecule to investigate the general properties of carboxylic acids. FA is also an atmospherically and astrophysically relevant molecule. It is well known that its dimeric form is predominant in the gas phase at temperatures below 423 K. The cyclic conformation of the dimer (FACD) is an elementary system to be understood for the concerted hydrogen transfer through equivalent hydrogen bonds, an essential process within biomolecules. The IR range is a crucial spectral region, particularly the far-IR, as it gives a direct access to the intermolecular vibrational modes involved in this process. Moreover, due to its centrosymmetric conformation, the FACD exhibits no pure rotation spectrum and, due to spectral line congestion and Doppler broadening, IR bands cannot be rotationally resolved at room temperature. So far, only parts of the ν_{5}-GS band (C-O stretch) have been observed under jet-cooled conditions using laser techniques. We present here six rotationally resolved IR bands of FACD recorded under jet-cooled conditions using the Jet-AILES apparatus and the QCL spectrometer at MONARIS, including the far-IR ν_{24}-GS band (intermolecular in-plane bending). Splitting due to vibration-rotation-tunneling motions are clearly observed. A full spectral analysis is in progress starting from the GS constants obtained by Goroya et al. and with the support of electronic structure calculations. T. Miyazawa and K. S. Pitzer, J. Am. Chem. Soc. 81, 74, 1959 R. Georges, M. Freytes, D. Hurtmans, I. Kleiner, J. Vander Auwera, M. Herman, Chem. Phys. 305, 187, 2004 M. Ortlieb and M. Havenith, J. Phys. Chem. A 111, 7355, 2007; K. G. Goroya, Y. Zhu, P. Sun and C. Duan, J. Chem. Phys. 140, 164311, 2014 This work is supported by the CaPPA project (Chemical and Physical Properties of the Atmosphere) ANR-11-LABX-0005-01

IR Spectrometer Using 90-degree Off-axis Parabolic Mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert M. Malone, Richard, G. Hacking, Ian J. McKenna, and Daniel H. Dolan

2008-09-02

A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light ource at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output IR recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the secondmore » parabolic mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement singlepoint pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.« less

Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks.

PubMed

Yan, Chang; Nishida, Jun; Yuan, Rongfeng; Fayer, Michael D

2016-08-03

Water of hydration plays an important role in minerals, determining their crystal structures and physical properties. Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump-probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O). 2D IR spectra revealed that water arrangement in freshly precipitated gypsum contained a small amount of inhomogeneity. Following annealing at 348 K, water molecules became highly ordered; the 2D IR spectrum became homogeneously broadened (motional narrowed). PSPP measurements observed only inertial orientational relaxation. In contrast, water in bassanite's tubular channels is dynamically disordered. 2D IR spectra showed a significant amount of inhomogeneous broadening caused by a range of water configurations. At 298 K, water dynamics cause spectral diffusion that sampled a portion of the inhomogeneous line width on the time scale of ∼30 ps, while the rest of inhomogeneity is static on the time scale of the measurements. At higher temperature, the dynamics become faster. Spectral diffusion accelerates, and a portion of the lower temperature spectral diffusion became motionally narrowed. At sufficiently high temperature, all of the dynamics that produced spectral diffusion at lower temperatures became motionally narrowed, and only homogeneous broadening and static inhomogeneity were observed. Water angular motions in bassanite exhibit temperature-dependent diffusive orientational relaxation in a restricted cone of angles. The experiments were made possible by eliminating the vast amount of scattered light produced by the granulated powder samples using phase cycling methods.

Mid-IR Plasmonics, Cavity Coupled Excitations, and IR Spectra of Individual Airborne Particulate Matter

NASA Astrophysics Data System (ADS)

Luthra, Antriksh

With the advances in plasmonics, new fields have evolved involving the mixing of light with various states like Surface Plasmons (SPs), Surface Phonons (SPh), molecular emitters or resonators, and wavelength scale cavities. This work concentrates on the interaction of infrared (IR) light with SPs, cavity modes, and molecular vibrations. In the first chapter, the field of Plasmonics is introduced from a classical and a quantum mechanical perspective and a comparison of both is presented. In Chapter 2, the interaction of cavity modes with vibrations is discussed. Briefly, when IR light is illuminated upon an etalon, its fringes disperse as function of angle. If there is a dielectric in a cavity having a vibrational transition in the fringe region, it leads to a strong interaction that gives rise to a Rabi splitting. Data was obtained from collaborators at the U.S. Naval Research Laboratory (NRL) and a derivation for the dispersion of etalon cavity modes was carried out to model the peak positions of the fringes. In Chapter 3, the excitation of Surface Plasmons Polaritons (SPPs) on metal bi-gratings is discussed. The resonance condition occurs when the momentum of the IR light parallel to the surface plus the grating vector match the momentum of the SPP. Experiments were performed in the GammaX space (ky=0) and the resonance peak positions were modeled with SPP momentum matching equations. In Chapter 4, the application of plasmonics in the mid-IR frequency range that overlaps with the frequencies of molecular vibrations is explored. The plasmonic mesh has interesting optical properties, it focuses more light in the holes and that leads to an enhancement of the IR spectra of a particle trapped in the mesh hole. In this work, plasmonic mesh is used to study airborne particles that are usually difficult to study using FTIR spectroscopy due to strong Mie scattering effect. Respiring dust particles of 4 microns size has significant negative health consequences. Different

ZnO nanoparticles based fiber optic gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narasimman, S.; Sivacoumar, R.; Alex, Z. C.

In this work, ZnO nanoparticles were synthesized by simple aqueous chemical route method. The synthesized ZnO nanoparticles were characterized by X-ray diffraction and scanning electron microscope. The sensitivity of the nanoparticles was studied for different gases like acetone, ammonia and ethanol in terms of variation in spectral light intensity. The XRD and SEM analysis confirms the formation of hexagonal wurtzite structure with the grain size of 11.2 nm. The small cladding region of the optical fiber was replaced with the synthesized nanoparticles. The light spectrum was recorded for different gas concentrations. The synthesized nanoparticles showed high sensitivity towards ammonia in lowmore » ppm level and acetone in high ppm level.« less

Attenuation of near-IR light through dentin at wavelengths from 1300–1650-nm

PubMed Central

Chan, Andrew C.; Darling, Cynthia L.; Chan, Kenneth H.; Fried, Daniel

2014-01-01

Light scattering in dental enamel decreases markedly from the UV to the near-IR and recent studies employing near-IR transillumination and reflectance imaging including optical coherence tomography indicate that this wavelength region is ideally suited for imaging dental caries due to the high transparency of enamel. The opacity of dentin is an important factor in optimizing the contrast of demineralization in reflectance measurements. It also influences the contrast of occlusal lesions in transillumination. Light scattering in dentin is an order of magnitude larger than in enamel, it is highly anisotropic and has a different spectral light scattering dependence than enamel. The objective of this study was to measure the optical attenuation of near-IR light through dentin at near-IR wavelengths from 1300–1650-nm. In this study the collimated transmission of near-IR light through polished thin sections of dentin of 0.05 to 0.6 mm thickness was measured. Beer-Lambert plots show that the attenuation coefficients range in magnitude from 20 to 40 cm−1. Attenuation increased significantly with increasing wavelength and the increases were not entirely consistent with increased water absorption. PMID:24839373

Spectral gain measurements of quantum confined emitters, and design and fabrication of intersubband quantum box laser structures

NASA Astrophysics Data System (ADS)

Tsvid, Gene

Semiconductor laser active regions are commonly characterized by photo- and electro-luminescence (PL, EL) and cavity length analysis. However quantitative spectral information is not readily extracted from PL and EL data and comparison of different active region materials can be difficult. More quantifiable spectral information is contained in the optical gain spectra. This work reports on spectral gain studies, using multi-segmented interband devices, of InGaAs quantum well and quantum dot active regions grown by metalorganic chemical vapor deposition (MOCVD). Using the fundamental connection between gain and spontaneous emission spectra, the spontaneous radiative current and spontaneous radiative efficiency is evaluated for these active regions. The spectral gain and spontaneous radiative efficiency measurements of 980 nm emitting InGaAs quantum well (QW) material provides a benchmark comparison to previous results obtained on highly-strained, 1200 nm emitting InGaAs QW material. These studies provide insight into carrier recombination and the role of the current injection efficiency in InGaAs QW lasers. The spectral gain of self-assembled MOCVD grown InGaAs quantum dots (QD) active regions are also investigated, allowing for comparison to InGaAs QW material. The second part of my talk will cover intersubband-transition QW and quantum-box (QB) lasers. Quantum cascade (QC) lasers have emerged as compact and technologically important light sources in the mid-infrared (IR) and far-IR wavelength ranges infringing on the near-IR and terahertz spectral regions respectively. However, the overall power conversion efficiency, so-called wallplug efficiency, of the best QC lasers, emitting around 5 microns, is ˜9% in CW operation and very unlikely to exceed 15%. In order to dramatically improve the wallplug efficiency of mid-IR lasers (i.e., to about 50%), intersubband QB (IQB) lasers have been proposed. The basic idea, the optimal design and the progress towards the

IN SITU INFRARED MEASUREMENTS OF FREE-FLYING SILICATE DURING CONDENSATION IN THE LABORATORY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishizuka, Shinnosuke; Kimura, Yuki; Sakon, Itsuki

2015-04-20

We developed a new experimental system for infrared (IR) measurements on free-flying nucleating nanoparticles in situ and applied it to studies on silicate particles. We monitored the condensation of magnesium-bearing silicate nanoparticles from thermally evaporated magnesium and silicon monoxide vapor under an atmosphere of oxygen and argon. The IR spectrum of newly condensed particles showed a spectral feature for non-crystalline magnesium-bearing silicate that is remarkably consistent with the IR spectrum of astronomically observed non-crystalline silicate around oxygen-rich evolved stars. The silicate crystallized at <500 K and eventually developed a high crystallinity. Because of the size effects of nanoparticles, the silicatemore » would be expected to be like a liquid at least during the initial stages of nucleation and growth. Our experimental results therefore suggest decreasing the possible formation temperature of crystalline silicates in dust formation environments with relatively higher pressure.« less

Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy.

PubMed

Qu, Lei; Chen, Jian-Bo; Zhang, Gui-Jun; Sun, Su-Qin; Zheng, Jing

2017-03-05

As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p=0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR. Copyright © 2016 Elsevier B.V. All rights reserved.

The pressure tunning Raman and IR spectral studies on the multinuclear metal carbyne complexes

NASA Astrophysics Data System (ADS)

Xu, Zhenhua; Butler, Ian S.; Mayr, Andreas

2005-03-01

The Raman and infrared (IR) spectra of four tungsten metal carbyne complexes I, II, IV and V [Cl(CO) 2(L)W tbnd CC 6H 4sbnd (C tbnd CC 6H 4) nsbnd N tbnd C sbnd ] 2M (L = TMEDA, n = 0, M = PdI 2 or ReCl(CO) 3; L = DPPE, n = 1, M = PdI 2 or ReCl(CO) 3) were studied at high external pressure. Their pressure-induced phase transitions were observed near 20 kbar (complexes I), 15 kbar (complexes II), 25 kbar (complex IV) and 30 kbar (complex V). The pressure-induced phase transition likely is first order in complex I and the pressure-induced phase transitions of complexes II, IV and V are mostly second order. The pressure sensitivities d ν/d p of ν(W tbnd C) are high in the low-pressure phase area and very low in the high-pressure phase area due to the pressure strengthening π back-bonding from metal W to π * orbital of C tbnd O in fragment Cl(CO) 2(L)W tbnd C. The pressure strengthening metal π back-bonding from metal Re or Pd to π * orbital of C tbnd O or C tbnd N also happened to both of central metal centers of NCPd(I 2)CN in complex I and NCReCl(CO) 3CN in complex II.

Comparative structural analysis of cytidine, ethenocytidine and their protonated salts. II. IR spectral studies.

PubMed Central

Krzyzosiak, W; Jaskólski, M; Sierzputowska-Gracz, H; Wiewiórowski, M

1982-01-01

The IR spectra of crystalline cytidine (Cyd), ethenocytidine (epsilon Cyd), and their hydrochlorides (Cyd-Hcl and epsilon CyD-HCl) have been analyzed to determine the spectroscopic manifestations of the structural differences that were previously established for these nucleosides from X-ray studies. O,N-Deuteration of the samples turned out to be a successful approach to obtaining interpretable spectra. The analysis was carried out in three frequency ranges: (i) The 2600-1900 cm-1 range originating from the vO-D and VN-D vibrations. All intermolecular hydrogen bonds could be recognized here. The positions of the individual vO-D (vN-D) bands were correlated with the geometrical delta HB parameters presenting the strengths of hydrogen bonds in which these groups act as donors (ii) The 1750-1500 cm-1 region originating from the stretching vibrations of double bonds. All absorption bands in this region were interpreted in terms of electronic structures of the base fragments. (iii) The region of the C-H stretching vibrations of the base fragments (3200-3000 cm-1) and sugar moieties (3000-2800 cm-1). The Csp2-H vibrations also reflect the electronic structures of the base fragments, whereas the vCsp-H frequencies seem to be sensitive to etheno-bridging and to the presence of an intramolecular C6-H...05' hydrogen bond. PMID:7079184

Hydrophobic binding peptide-conjugated hybrid lipid-mesoporous silica nanoparticles for effective chemo-photothermal therapy of pancreatic cancer.

PubMed

Thapa, Raj Kumar; Nguyen, Hanh Thuy; Gautam, Milan; Shrestha, Aarajana; Lee, Eung Seok; Ku, Sae Kwang; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

2017-11-01

Nanoparticle-based drug delivery systems are designed to reach tumor sites based on their enhanced permeation and retention effects. However, a lack of interaction of these nanoparticles with cancer cells might lead to reduced uptake in the tumors, which might compromise the therapeutic efficacy of the system. Therefore, we developed bortezomib and IR-820-loaded hybrid-lipid mesoporous silica nanoparticles conjugated with the hydrophobic-binding peptide, cyclosporine A (CsA), and referred to them as CLMSN/BIR. Upon reaching the tumor site, CsA interacts hydrophobically with the cancer cell membranes to allow effective uptake of the nanoparticles. Nanoparticles ∼160 nm in size were prepared and the stability of IR-820 significantly improved. High cellular uptake of the nanoparticles was evident with pronounced apoptotic effects in PANC-1 and MIA PaCa-2 cells that were mediated by the chemotherapeutic effect of bortezomib and the photothermal and reactive oxygen species generation effects of IR-820. An in vivo biodistribution study indicated there was high accumulation in the tumor with an enhanced photothermal effect in PANC-1 xenograft mouse tumors. Furthermore, enhanced antitumor effects in PANC-1 xenograft tumors were observed with minimal toxicity induction in the organs of mice. Cumulatively, these results indicated the promising effects of CLMSN/BIR for effective chemo-phototherapy of pancreatic cancers.

FT-IR and Zeta potential measurements on TiO nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Jaiveer; Rathore, Ravi; Kaurav, Netram, E-mail: netramkaurav@yahoo.co.uk

2016-05-23

In the present investigation, ultrafine TiO particles have been synthesized successfully by thermal decomposition method. The sample was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. As-synthesized TiO nanoparticles have a cubic structure as characterized by power X-ray diffraction (XRD), which shows that TiO nanoparticles have narrow size distribution with particle size 11.5 nm. FTIR data shows a strong peak at 1300 cm{sup −1}, assignable to the Ti-O stretching vibrations mode.

Computer-generated predictions of the structure and of the IR and Raman spectra of VX. Final report, May-August 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hameka, H.F.; Jensen, J.O.

1993-05-01

This report presents the computed optimized geometry and vibrational IR and Raman frequencies of the V-agent VX. The computations are performed with the Gaussian 90 Program Package using 6-31G* basis sets. We assign the vibrational frequencies and correct each frequency by multiplying it with a previously derived 6-31G* correction factor. The result is a computer-generated prediction of the IR and Raman spectra of VX. This study was intended as a blind test of the utility of IR spectral prediction. Therefore, we intentionally did not look at experimental data on the IR and Raman spectra of VX.... IR Spectra, VX, Ramanmore » spectra, Computer predictions.« less

Standoff aircraft IR characterization with ABB dual-band hyper spectral imager

NASA Astrophysics Data System (ADS)

Prel, Florent; Moreau, Louis; Lantagne, Stéphane; Bullis, Ritchie D.; Roy, Claude; Vallières, Christian; Levesque, Luc

2012-09-01

Remote sensing infrared characterization of rapidly evolving events generally involves the combination of a spectro-radiometer and infrared camera(s) as separated instruments. Time synchronization, spatial coregistration, consistent radiometric calibration and managing several systems are important challenges to overcome; they complicate the target infrared characterization data processing and increase the sources of errors affecting the final radiometric accuracy. MR-i is a dual-band Hyperspectal imaging spectro-radiometer, that combines two 256 x 256 pixels infrared cameras and an infrared spectro-radiometer into one single instrument. This field instrument generates spectral datacubes in the MWIR and LWIR. It is designed to acquire the spectral signatures of rapidly evolving events. The design is modular. The spectrometer has two output ports configured with two simultaneously operated cameras to either widen the spectral coverage or to increase the dynamic range of the measured amplitudes. Various telescope options are available for the input port. Recent platform developments and field trial measurements performances will be presented for a system configuration dedicated to the characterization of airborne targets.

Trade-off studies of a hyperspectral infrared sounder on a geostationary satellite.

PubMed

Wang, Fang; Li, Jun; Schmit, Timothy J; Ackerman, Steven A

2007-01-10

Trade-off studies on spectral coverage, signal-to-noise ratio (SNR), and spectral resolution for a hyperspectral infrared (IR) sounder on a geostationary satellite are summarized. The data density method is applied for the vertical resolution analysis, and the rms error between true and retrieved profiles is used to represent the retrieval accuracy. The effects of spectral coverage, SNR, and spectral resolution on vertical resolution and retrieval accuracy are investigated. The advantages of IR and microwave sounder synergy are also demonstrated. When focusing on instrument performance and data processing, the results from this study show that the preferred spectral coverage combines long-wave infrared (LWIR) with the shorter middle-wave IR (SMidW). Using the appropriate spectral coverage, a hyperspectral IR sounder with appropriate SNR can achieve the required science performance (1 km vertical resolution, 1 K temperature, and 10% relative humidity retrieval accuracy). The synergy of microwave and IR sounders can improve the vertical resolution and retrieval accuracy compared to either instrument alone.

Material of LAPAN's thermal IR camera equipped with two microbolometers in one aperture

NASA Astrophysics Data System (ADS)

Bustanul, A.; Irwan, P.; Andi M., T.

2017-11-01

Besides the wavelength used, there is another factor that we have to notice in designing an optical system. It is material used which is correct for the spectral bands determined. Basically, due the limitation of the available range and expensive, choosing and determining materials for Infra Red (IR) wavelength are more difficult and complex rather than visible spectrum. We also had the same problem while designing our thermal IR camera equipped with two microbolometers sharing aperture. Two spectral bands, 3 - 4 μm (MWIR) and 8 - 12 μm (LWIR), have been decided to be our thermal IR camera spectrum to address missions, i.e., peat land fire, volcanoes activities, and Sea Surface Temperature (SST). Referring those bands, we chose the appropriate material for LAPAN's IR camera optics. This paper describes material of LAPAN's IR camera equipped with two microbolometer in one aperture. First of all, we were learning and understanding of optical materials properties all matters of IR technology including its bandwidths. Considering some aspects, i.e., Transmission, Index of Refraction, Thermal properties covering the index gradient and coefficient of thermal expansion (CTE), the analysis then has been accomplished. Moreover, we were utilizing a commercial software, Thermal Desktop/Sinda Fluint, to strengthen the process. Some restrictions such as space environment, low cost, and performance mainly durability and transmission, were also cared throughout the trade off the works. The results of all those analysis, either in graphs or in measurement, indicate that the lens of LAPAN's IR camera with sharing aperture is based on Germanium/Zinc Selenide materials.

2.5 TW, two-cycle IR laser pulses via frequency domain optical parametric amplification.

PubMed

Gruson, V; Ernotte, G; Lassonde, P; Laramée, A; Bionta, M R; Chaker, M; Di Mauro, L; Corkum, P B; Ibrahim, H; Schmidt, B E; Legaré, F

2017-10-30

Broadband optical parametric amplification in the IR region has reached a new milestone through the use of a non-collinear Frequency domain Optical Parametric Amplification system. We report a laser source delivering 11.6 fs pulses with 30 mJ of energy at a central wavelength of 1.8 μm at 10 Hz repetition rate corresponding to a peak power of 2.5 TW. The peak power scaling is accompanied by a pulse shortening of about 20% upon amplification due to the spectral reshaping with higher gain in the spectral wings. This source paves the way for high flux soft X-ray pulses and IR-driven laser wakefield acceleration.

Oxadiazole-carbazole polymer (POC)-Ir(ppy)3 tunable emitting composites

NASA Astrophysics Data System (ADS)

Bruno, Annalisa; Borriello, Carmela; Di Luccio, Tiziana; Sessa, Lucia; Concilio, Simona; Haque, Saif A.; Minarini, Carla

2017-04-01

POC polymer is an oxadiazole-carbazole copolymer we have previously synthetized and established as light emitting material in Organic Light Emitting Devices (OLEDs), although POC quantum yield emission efficiency and color purity still need to be enhanced. On the other hand, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) complexes, namely Ir(ppy)3 are among the brightest luminophores employed in green light emitting devices. Our aim, in this work, is to take advantage of Ir(ppy)3 bright emission by combining the Ir complex with blue emitting POC to obtain tunable light emitting composites over a wide range of the visible spectrum. Here we have investigated the optical proprieties POC based nanocomposites with different concentrations of Ir(ppy)3, ranging from 1 to 10 wt%. Both spectral and time resolved fluorescence measurements show an efficient energy transfer from the polymer to the dopants, resulting in white-emitting composites. The most intense and stable emission has been found when POC was doped with about 5 wt% concentration of Ir(ppy)3.

Molecular imaging and sensing using plasmonic nanoparticles

NASA Astrophysics Data System (ADS)

Crow, Matthew James

Noble metal nanoparticles exhibit unique optical properties that are beneficial to a variety of applications, including molecular imaging. The large scattering cross sections of nanoparticles provide high contrast necessary for biomarkers. Unlike alternative contrast agents, nanoparticles provide refractive index sensitivity revealing information regarding the local cellular environment. Altering the shape and composition of the nanoparticle shifts the peak resonant wavelength of scattered light, allowing for implementation of multiple spectrally distinct tags. In this project, nanoparticles that scatter in different spectral windows are functionalized with various antibodies recognizing extra-cellular receptors integral to cancer progression. A hyperspectral imaging system is developed, allowing for visualization and spectral characterization of cells labeled with these conjugates. Various molecular imaging and microspectroscopy applications of plasmonic nanoparticles are then investigated. First, anti-EGFR gold nanospheres are shown to quantitatively measure receptor expression with similar performance to fluorescence assays. Second, anti-EGFR gold nanorods and novel anti-IGF-1R silver nanospheres are implemented to indicate local cellular refractive indices. Third, because biosensing capabilities of nanoparticle tags may be limited by plasmonic coupling, polarization mapping is investigated as a method to discern these effects. Fourth, plasmonic coupling is tested to monitor HER-2 dimerization. Experiments reveal the interparticle conformation of proximal HER-2 bound labels, required for plasmonic coupling-enhanced dielectric sensing. Fifth, all three functionalized plasmonic tags are implemented simultaneously to indicate clinically relevant cell immunophenotype information and changes in the cellular dielectric environment. Finally, flow cytometry experiments are conducted utilizing the anti-EGFR nanorod tag to demonstrate profiling of receptor expression

Electrosynthesis and characterization of zinc tungstate nanoparticles

NASA Astrophysics Data System (ADS)

Rahimi-Nasrabadi, Mehdi; Pourmortazavi, Seied Mahdi; Ganjali, Mohammad Reza; Hajimirsadeghi, Seiedeh Somayyeh; Zahedi, Mir Mahdi

2013-09-01

Zinc tungstate nanoparticles with different sizes are produced through an electrolysis process including a zinc plate anode in sodium tungstate solution. The shape and size of the product was found to be controlled by varying reaction parameters such as electrolysis voltage, stirring rate of electrolyte solution and temperature. The morphological (SEM) characterization analysis was performed on the product and UV-Vis spectrophotometry and FT-IR spectroscopy was utilized to characterize the electrodeposited nanoparticles. Study of the particle size of the product versus the electrolysis voltage showed that, increasing the voltage from 4 to 8 V, led to the particle size of zinc tungstate to decrease, but further increasing the voltage from 8 to 12 V, the particle size of the produced particles increased. The size and shape of the product was also found to be dependent on the stirring rate and temperature of the electrolyte solution. X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, and photoluminescence, were used to study the structure as well as composition of the nano-material prepared under optimum conditions.

FT-IR spectrum of grape seed oil and quantum models of fatty acids triglycerides

NASA Astrophysics Data System (ADS)

Berezin, K. V.; Antonova, E. M.; Shagautdinova, I. T.; Chernavina, M. L.; Dvoretskiy, K. N.; Grechukhina, O. N.; Vasilyeva, L. M.; Rybakov, A. V.; Likhter, A. M.

2018-04-01

FT-IR spectra of grape seed oil and glycerol were registered in the 650-4000 cm-1 range. Molecular models of glycerol and some fatty acids that compose the oil under study - linoleic, oleic, palmitic and stearic acids - as well as their triglycerides were developed within B3LYP/6-31G(d) density functional model. A vibrating FT-IR spectrum of grape seed oil was modeled on the basis of calculated values of vibrating wave numbers and IR intensities of the fatty acids triglycerides and with regard to their percentage. Triglyceride spectral bands that were formed by glycerol linkage vibrations were revealed. It was identified that triglycerol linkage has a small impact on the structure of fatty acids and, consequently, on vibrating wave numbers. The conducted molecular modeling became a basis for theoretical interpretation on 10 experimentally observed absorption bands in FT-IR spectrum of grape seed oil.

Formation of nanoparticles from thin silver films irradiated by laser pulses in air

NASA Astrophysics Data System (ADS)

Nastulyavichus, A. A.; Smirnov, N. A.; Kudryashov, S. I.; Ionin, A. A.; Saraeva, I. N.; Busleev, N. I.; Rudenko, A. A.; Khmel'nitskii, R. A.; Zayarnyi, D. A.

2018-03-01

Some specific features of the transport of silver nanoparticles onto a SiO2 substrate under focused nanosecond IR laser pulses is experimentally investigated. A possibility of obtaining silver coatings is demonstrated. The formation of silver nanostructures as a result of pulsed laser ablation in air is studied. Nanoparticles are formed by exposing a silver film to radiation of an HTF MARK (Bulat) laser marker (λ = 1064 nm). The thus prepared nanoparticles are analysed using scanning electron microscopy and optical spectroscopy.

Green synthesis of silver nanoparticles using tannins

NASA Astrophysics Data System (ADS)

Raja, Pandian Bothi; Rahim, Afidah Abdul; Qureshi, Ahmad Kaleem; Awang, Khalijah

2014-09-01

Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.

Electron magnetic resonance and magnetooptical studies of nanoparticle-containing borate glasses

NASA Astrophysics Data System (ADS)

Kliava, Janis; Edelman, Irina; Ivanova, Oxana; Ivantsov, Ruslan; Petrakovskaja, Eleonora; Hennet, Louis; Thiaudière, Dominique; Saboungi, Marie-Louise

2011-03-01

We report electron magnetic resonance (EMR) and magnetooptical studies of borate glasses of molar composition 22.5K 2O-22.5Al 2O 3-55B 2O 3 co-doped with low concentrations of Fe 2O 3 and MnO. In as-prepared samples the paramagnetic ions, as a rule, are in diluted state. However, in the case where the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles with characteristics close to those of manganese ferrite are formed already at the first stage of the glass preparation, as evidenced by both magnetic circular dichroism (MCD) and EMR. After thermal treatment all glasses show characteristic MCD and EMR spectra, attesting to the presence of magnetic nanoparticles, predominantly including iron ions. Preliminary EXAFS measurements at the Fe K-absorption edge show an emergence of nanoparticles with a structure close to MnFe 2O 4 after annealing the glasses at 560 °C. By computer simulating the EMR spectra at variable temperatures, a superparamagnetic nature of relatively broad size and shape distribution with the average diameter of ca. 3-4 nm. The characteristic temperature-dependent shift of the apparent resonance field is explained by a strong temperature dependence of the magnetic anisotropy in the nanoparticles. The formation of magnetic nanoparticles confers to the potassium-alumina-borate glasses magnetic and magneto-optical properties typical of magnetically ordered substances. At the same time, they remain transparent in a part of the visible and near infrared spectral range and display a high Faraday rotation value.

Spectral study of interaction between chondroitin sulfate and nanoparticles and its application in quantitative analysis

NASA Astrophysics Data System (ADS)

Ma, Yi; Wei, Maojie; Zhang, Xiao; Zhao, Ting; Liu, Xiumei; Zhou, Guanglian

2016-01-01

In this work, the interaction between chondroitin sulfate (CS) and gold nanoparticles (GNPs) and silver nanoparticles (SNPs) was characterized for the first time. Plasma resonance scattering (PRS) and plasma resonance absorption (PRA) were used to investigate the characteristics of their spectrum. The results suggested that the CS with negative charge could interact with metal nanoparticles with negative charge and the adsorption of CS on the surface of SNPs was more regular than that of GNPs. The resonance scattering spectra also further confirmed the interaction between CS and SNPs. A new method for detection of CS based on the interaction was developed. CS concentrations in the range of 0.02-3.5 μg/mL were proportional to the decreases of absorbance of SNPs. Compared with other reported methods, the proposed method is simple and workable without complex process, high consumption and expensive equipments. The developed method was applied to the determination of the CS contents from different biological origins and the results were compared with those obtained by the method of Chinese Pharmacopeia. The effects of matrix in plasma and other glycosaminoglycans on the determination of CS were also investigated. The results showed that a small quantity of blood plasma had no effect on the determination of CS and when the concentration ratio of CS to heparin was more than 10:1, the influence of heparin on the detection of CS could be ignored. This work gave a specific research direction for the detection of CS in the presence of metal nanoparticles.

Gaz Phase IR and UV Spectroscopy of Neutral Contact Ion Pairs

NASA Astrophysics Data System (ADS)

Habka, Sana; Brenner, Valerie; Mons, Michel; Gloaguen, Eric

2016-06-01

Cations and anions, in solution, tend to pair up forming ion pairs. They play a crucial role in many fundamental processes in ion-concentrated solutions and living organisms. Despite their importance and vast applications in physics, chemistry and biochemistry, they remain difficult to characterize namely because of the coexistence of several types of pairing in solution. However, an interesting alternative consists in applying highly selective gas phase spectroscopy which can offer new insights on these neutral ion pairs. Our study consists in characterizing contact ion pairs (CIPs) in isolated model systems (M+, Ph-(CH2)n-COO- with M=Li, Na, K, Rb, Cs, and n=1-3), to determine their spectral signatures and compare them to ion pairs in solution. We have used laser desorption to vaporize a solid tablet containing the desired salt. Structural information for each system was obtained by mass-selective, UV and IR laser spectroscopy combined with high level quantum chemistry calculations1. Evidence of the presence of neutral CIPs was found by scanning the π-π* transition of the phenyl ring using resonant two-photon ionization (R2PI). Then, conformational selective IR/UV double resonance spectra were recorded in the CO2- stretch region for each conformation detected. The good agreement between theoretical data obtained at the BSSE-corrected-fullCCSD(T)/dhf-TZVPP//B97-D3/dhf-TZVPP level and experimental IR spectra led us to assign the 3D structure for each ion pair formed. Spectral signatures of (M+, Ph-CH2-COO-) pairs, were assigned to a bidentate CIPs between the alkali cation and the carboxylate group. In the case of (Li+, Ph-(CH2)3-COO-) pairs, the presence of a flexible side chain promotes a cation-π interaction leading to a tridentate O-O-π structure with its unique IR and UV signatures. IR spectra obtained on isolated CIPs were found very much alike the ones published on lithium and sodium acetate in solution2. However, in the case of sodium acetate, solution

The EarthCARE multi spectral imager thermal infrared optical unit

NASA Astrophysics Data System (ADS)

Chang, M. P. J. L.; Woods, D.; Baister, Guy; Lobb, Dan; Wood, Trevor

2017-11-01

The EarthCARE satellite mission objective is the observation of clouds and aerosols from low Earth orbit. The key spatial context providing instrument within the payload suite of 4 instruments is the Multi-Spectral Imager (MSI), previously described in [1]. The MSI is intended to provide information on the horizontal variability of the atmospheric conditions and to identify e.g. cloud type, textures, and temperature. It will form Earth images at 500m ground sample distance (GSD) over a swath width of 150km; it will image Earth in 7 spectral bands: one visible, one near-IR, two short-wave IR and three thermal IR. The instrument will be comprised of two key parts: • a visible-NIR-SWIR (VNS) optical unit radiometrically calibrated using a sun illuminated quasivolume diffuser and shutter system • a thermal IR (TIR) optical unit radiometrically calibrated using cold space and an internal black-body. This paper, being the first of a sequence of two, will provide an overview of the MSI and enter into more detail the critical performance parameters and detailed design the MSI TIR optical design. The TIR concept is to provide pushbroom imaging of its 3 bands through spectral separation from a common aperture. The result is an efficient, well controlled optical design without the need for multiple focal plane arrays. The designed focal plane houses an area array detector and will meet a challenging set of requirements, including radiometric resolution, accuracy, distortion and MTF.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes.

PubMed

Harrington, Walter N; Haji, Mwafaq R; Galanzha, Ekaterina I; Nedosekin, Dmitry A; Nima, Zeid A; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S; Zharov, Vladimir P

2016-11-08

Photoswitchable fluorescent proteins with controllable light-dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light-dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes

NASA Astrophysics Data System (ADS)

Harrington, Walter N.; Haji, Mwafaq R.; Galanzha, Ekaterina I.; Nedosekin, Dmitry A.; Nima, Zeid A.; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S.; Zharov, Vladimir P.

2016-11-01

Photoswitchable fluorescent proteins with controllable light-dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light-dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes

PubMed Central

Harrington, Walter N.; Haji, Mwafaq R.; Galanzha, Ekaterina I.; Nedosekin, Dmitry A.; Nima, Zeid A.; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S.; Zharov, Vladimir P.

2016-01-01

Photoswitchable fluorescent proteins with controllable light–dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light–dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy. PMID:27824110

Far-IR measurements at Cerro Toco, Chile: FIRST, REFIR, and AERI

NASA Astrophysics Data System (ADS)

Cageao, Richard P.; Alford, J. Ashley; Johnson, David G.; Kratz, David P.; Mlynczak, Martin G.

2010-09-01

In mid-2009, the Radiative Heating in the Underexplored Bands Campaign II (RHUBC-II) was conducted from Cerro Toco, Chile, a high, dry, remote mountain plateau, 23°S , 67.8°W at 5.4km, in the Atacama Desert of Northern Chile. From this site, dominant IR water vapor absorption bands and continuum, saturated when viewed from the surface at lower altitudes, or in less dry locales, were investigated in detail, elucidating infrared (IR) absorption and emission in the atmosphere. Three Fourier Transform InfraRed (FTIR) instruments were at the site, the Far-Infrared Spectroscopy of the Troposphere (FIRST), the Radiation Explorer in the Far Infrared (REFIR), and the Atmospheric Emitted Radiance Interferometer (AERI). In a side-by-side comparison, these measured atmospheric downwelling radiation, with overlapping spectral coverage from 5 to 100μm (2000 to 100cm-1), and instrument spectral resolutions from 0.5 to 0.643cm-1, unapodized. In addition to the FTIR and other ground-based IR and microwave instrumentation, pressure/temperature/relative humidity measuring sondes, for atmospheric profiles to 18km, were launched from the site several times a day. The derived water vapor profiles, determined at times matching the FTIR measurement times, were used to model atmospheric radiative transfer. Comparison of instrument data, all at the same spectral resolution, and model calculations, are presented along with a technique for determining adjustments to line-by-line calculation continuum models. This was a major objective of the campaign.

Far-IR Measurements at Cerro Toco, Chile: FIRST, REFIR, and AERI

NASA Technical Reports Server (NTRS)

Cageao, Richard P.; Alford, J. Ashley; Johnson, David G.; Kratz, David P.; Mlynczak, Martin G.

2010-01-01

In mid-2009, the Radiative Heating in the Underexplored Bands Campaign II (RHUBC-II) was conducted from Cerro Toco, Chile, a high, dry, remote mountain plateau, 23degS , 67.8degW at 5.4km, in the Atacama Desert of Northern Chile. From this site, dominant IR water vapor absorption bands and continuum, saturated when viewed from the surface at lower altitudes, or in less dry locales, were investigated in detail, elucidating IR absorption and emission in the atmosphere. Three FTIR instruments were at the site, the Far-Infrared Spectroscopy of the Troposphere (FIRST), the Radiation Explorer in the Far Infrared (REFIR), and the Atmospheric Emitted Radiance Interferometer (AERI). In a side-by-side comparison, these measured atmospheric downwelling radiation, with overlapping spectral coverage from 5 to100um (2000 to 100/cm), and instrument spectral resolutions from 0.5 to 0.64/cm, unapodized. In addition to the FTIR and other ground-based IR and microwave instrumentation, pressure/temperature/relative humidity measuring sondes, for atmospheric profiles to 18km, were launched from the site several times a day. The derived water vapor profiles, determined at times matching the FTIR measurement times, were used to model atmospheric radiative transfer. Comparison of instrument data, all at the same spectral resolution, and model calculations, are presented along with a technique for determining adjustments to line-by-line calculation continuum models. This was a major objective of the campaign.

Activity and Durability of Iridium Nanoparticles in the Oxygen Evolution Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alia, Shaun M.; Rasimick, Brian; Ngo, Chilan

Unsupported iridium (Ir) nanoparticles, that serve as standard oxygen evolution reaction (OER) catalysts in acidic electrolyzers, were investigated for electrochemical performance and durability in rotating disk electrode (RDE) half-cells. Fixed potential holds and potential cycling were applied to probe the durability of Ir nanoparticles, and performance losses were found to be driven by particle growth (coarsening) at moderate potential (1.4 to 1.6 V) and Ir dissolution at higher potential (>/=1.8 V). Several different commercially available samples were evaluated and standardized conditions for performance comparison are reported. In conclusion, the electrocatalyst RDE results have also been compared to results obtained formore » performance and durability in electrolysis cells.« less

Activity and Durability of Iridium Nanoparticles in the Oxygen Evolution Reaction

DOE PAGES

Alia, Shaun M.; Rasimick, Brian; Ngo, Chilan; ...

2016-07-15

Unsupported iridium (Ir) nanoparticles, that serve as standard oxygen evolution reaction (OER) catalysts in acidic electrolyzers, were investigated for electrochemical performance and durability in rotating disk electrode (RDE) half-cells. Fixed potential holds and potential cycling were applied to probe the durability of Ir nanoparticles, and performance losses were found to be driven by particle growth (coarsening) at moderate potential (1.4 to 1.6 V) and Ir dissolution at higher potential (>/=1.8 V). Several different commercially available samples were evaluated and standardized conditions for performance comparison are reported. In conclusion, the electrocatalyst RDE results have also been compared to results obtained formore » performance and durability in electrolysis cells.« less

Spectral Identification of New Galactic cLBV and WR Stars

NASA Astrophysics Data System (ADS)

Stringfellow, G. S.; Gvaramadze, V. V.; Beletsky, Y.; Kniazev, A. Y.

2012-12-01

We have undertaken a near-IR spectral survey of stars associated with compact nebulae recently revealed by the Spitzer and WISE imaging surveys. These circumstellar nebulae, produced by massive evolved stars, display a variety of symmetries and shapes and are often only evident at mid-IR wavelengths. Stars associated with ˜50 of these nebulae have been observed. We also obtained recent spectra of previously confirmed (known) luminous blue variables (LBVs) and candidate LBVs (cLBVs). The spectral similarity of the stars observed when compared directly to known LBVs and Wolf-Rayet (WR) stars indicate many are newly identified cLBVs, with a few being newly discovered WR stars, mostly of WN8-9h spectral type. These results suggest that a large population of previously unidentified cLBVs and related transitional stars reside in the Galaxy and confirm that circumstellar nebulae are inherent to most (c)LBVs.

Active and stable Ir@Pt core–shell catalysts for electrochemical oxygen reduction

DOE PAGES

Strickler, Alaina L.; Jackson, Ariel; Jaramillo, Thomas F.

2016-12-28

Electrochemical oxygen reduction is an important reaction for many sustainable energy technologies, such as fuel cells and metal–air batteries. Kinetic limitations of this reaction, expensive electrocatalysts, and catalyst instability, however, limit the commercial viability of such devices. Herein, we report an active Ir@Pt core–shell catalyst that combines platinum overlayers with nanostructure effects to tune the oxygen binding to the Pt surface, thereby achieving enhanced activity and stability for the oxygen reduction reaction. Ir@Pt nanoparticles with several shell thicknesses were synthesized in a scalable, inexpensive, one-pot polyol method. Electrochemical analysis demonstrates the activity and stability of the Ir@Pt catalyst, with specificmore » and mass activities increasing to 2.6 and 1.8 times that of commercial Pt/C (TKK), respectively, after 10 000 stability cycles. Furthermore, activity enhancement of the Ir@Pt catalyst is attributed to weakening of the oxygen binding to the Pt surface induced by the Ir core.« less

Design and development of hydrogel nanoparticles for mercaptopurine

PubMed Central

Senthil, V.; Kumar, R. Suresh; Nagaraju, C. V. V.; Jawahar, N.; Ganesh, G. N. K.; Gowthamarajan, K.

2010-01-01

Hydrogel nanoparticles have gained attention in recent years as they demonstrate the features and characters of hydrogels and nanoparticles at the same time. In the present study chitosan and carrageenan have been used, as hydrogel nanoparticles of mercaptopurine are developed using natural, biodegradable, and biocompatible polymers like chitosan and carrageenan. As these polymers are hydrophilic in nature, the particles will have a long life span in systemic circulation. Hydrogel nanoparticles with mercaptopurine is form an antileukemia drug by the counter polymer gelation method. Fourier-Transform Infrared (FT-IR) studies have shown a compatibility of polymers with the drug. The diameter of hydrogel nanoparticles was about 370 – 800 nm with a positive zeta potential of 26 – 30 mV. The hydrogel nanoparticles were almost spherical in shape, as revealed by scanning electron microscopy (SEM). Drug loading varied from 9 to 17%. Mercaptopurine released from the nanoparticles at the end of the twenty-fourth hour was about 69.48 – 76.52% at pH 7.4. The drug release from the formulation was following zero order kinetics, which was evident from the release kinetic studies and the mechanism of drug release was anomalous diffusion, which indicated that the drug release was controlled by more than one process. PMID:22247867

Spectral Diffusion: An Algorithm for Robust Material Decomposition of Spectral CT Data

PubMed Central

Clark, Darin P.; Badea, Cristian T.

2014-01-01

Clinical successes with dual energy CT, aggressive development of energy discriminating x-ray detectors, and novel, target-specific, nanoparticle contrast agents promise to establish spectral CT as a powerful functional imaging modality. Common to all of these applications is the need for a material decomposition algorithm which is robust in the presence of noise. Here, we develop such an algorithm which uses spectrally joint, piece-wise constant kernel regression and the split Bregman method to iteratively solve for a material decomposition which is gradient sparse, quantitatively accurate, and minimally biased. We call this algorithm spectral diffusion because it integrates structural information from multiple spectral channels and their corresponding material decompositions within the framework of diffusion-like denoising algorithms (e.g. anisotropic diffusion, total variation, bilateral filtration). Using a 3D, digital bar phantom and a material sensitivity matrix calibrated for use with a polychromatic x-ray source, we quantify the limits of detectability (CNR = 5) afforded by spectral diffusion in the triple-energy material decomposition of iodine (3.1 mg/mL), gold (0.9 mg/mL), and gadolinium (2.9 mg/mL) concentrations. We then apply spectral diffusion to the in vivo separation of these three materials in the mouse kidneys, liver, and spleen. PMID:25296173

Spectral diffusion: an algorithm for robust material decomposition of spectral CT data.

PubMed

Clark, Darin P; Badea, Cristian T

2014-11-07

Clinical successes with dual energy CT, aggressive development of energy discriminating x-ray detectors, and novel, target-specific, nanoparticle contrast agents promise to establish spectral CT as a powerful functional imaging modality. Common to all of these applications is the need for a material decomposition algorithm which is robust in the presence of noise. Here, we develop such an algorithm which uses spectrally joint, piecewise constant kernel regression and the split Bregman method to iteratively solve for a material decomposition which is gradient sparse, quantitatively accurate, and minimally biased. We call this algorithm spectral diffusion because it integrates structural information from multiple spectral channels and their corresponding material decompositions within the framework of diffusion-like denoising algorithms (e.g. anisotropic diffusion, total variation, bilateral filtration). Using a 3D, digital bar phantom and a material sensitivity matrix calibrated for use with a polychromatic x-ray source, we quantify the limits of detectability (CNR = 5) afforded by spectral diffusion in the triple-energy material decomposition of iodine (3.1 mg mL(-1)), gold (0.9 mg mL(-1)), and gadolinium (2.9 mg mL(-1)) concentrations. We then apply spectral diffusion to the in vivo separation of these three materials in the mouse kidneys, liver, and spleen.

Silver nanoparticles synthesized with Rumex hymenosepalus extracts: effective broad-spectrum microbicidal agents and cytotoxicity study.

PubMed

Rodríguez-León, Ericka; Íñiguez-Palomares, Ramón A; Navarro, Rosa Elena; Rodríguez-Beas, César; Larios-Rodríguez, Eduardo; Alvarez-Cirerol, Francisco J; Íñiguez-Palomares, Claudia; Ramírez-Saldaña, Maricela; Hernández Martínez, Javier; Martínez-Higuera, Aarón; Galván-Moroyoqui, José Manuel; Martínez-Soto, Juan Manuel

2017-08-21

We synthesized silver nanoparticles using Rumex hymenosepalus root extract (Rh). Nanoparticles were subjected to a purification process and final product is a composite of Rh and silver nanoparticles (AgNPsC). Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to perform a microstructure study. Additionally, two fractions (RhA and RhB) were obtained from the original extract by filtration with tetrahydrofuran (THF); both fractions were analyzed using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH); total polyphenol content was also determined. Separate inhibition tests for AgNPsC and RhA and RhB were applied to Gram-positive bacteria, Gram-negative bacteria, and yeast (Candida albicans) using the well diffusion method. Extract fractions were found to have inhibitory effects only over Gram-positive bacteria, and silver nanoparticles showed inhibitory effects over all the evaluated microorganisms. Cytotoxicity was evaluated using the tetrazolium dye (MTT) assay in mononuclear peripheral blood cells. In addition, we assessment AgNPsC in THP-1 monocyte cell line, using the cell viability estimation by trypan blue dye exclusion test (TB) and Live/Dead (LD) cell viability assays by confocal microscopy.

Green synthesis, characterization and catalytic degradation studies of gold nanoparticles against congo red and methyl orange.

PubMed

Umamaheswari, C; Lakshmanan, A; Nagarajan, N S

2018-01-01

The present study reports, novel and greener method for synthesis of gold nanoparticles (AuNPs) using 5,7-dihydroxy-6-metoxy-3 ' ,4 ' methylenedioxyisoflavone (Dalspinin), isolated from the roots of Dalbergia coromandeliana was carried out for the first time. The synthesized gold nanoparticles were characterized by UV-Vis spectroscopy, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The observed surface plasmon resonance (SPR) at 532nm in the UV-Vis absorption spectrum indicates the formation of gold nanoparticles. The powder XRD and SAED pattern for synthesized gold nanoparticles confirms crystalline nature. The HR-TEM images showed that the AuNPs formed were small in size, highly monodispersed and spherical in shape. The average particle sizes of the AuNPs are found to be ~10.5nm. The prepared AuNPs were found to be stable for more than 5months without any aggregation. The catalytic degradation studies of the synthesized AuNPs towards degradation of congo red and methyl orange, showed good catalytic in the complete degradation of both the dyes. The reduction catalyzed by gold nanoparticles followed the pseudo-first order kinetics, with a rate constant of 4.5×10 -3 s -1 (R 2 =0.9959) and 1.7×10 -3 s -1 (R 2 =0.9918) for congo red (CR) and methyl orange (MO), respectively. Copyright © 2017. Published by Elsevier B.V.

[Retrieval of the Optical Thickness and Cloud Top Height of Cirrus Clouds Based on AIRS IR High Spectral Resolution Data].

PubMed

Cao, Ya-nan; Wei, He-li; Dai, Cong-ming; Zhang, Xue-hai

2015-05-01

A study was carried out to retrieve optical thickness and cloud top height of cirrus clouds from the Atmospheric Infrared Sounder (AIRS) high spectral resolution data in 1070~1135 cm-1 IR band using a Combined Atmospheric Radiative Transfer model (CART) by brightness temperature difference between model simulation and AIRS observation. The research is based on AIRS LIB high spectral infrared observation data combined with Moderate Resolution Imaging Spectroradiometer (MODIS) cloud product data. Brightness temperature spectra based, on the retrieved cirrus optical thickness and cloud top height were simulated and compared with brightness temperature spectra of AIRS observation in the 650~1150 cm-1 band. The cirrus optical thickness and cloud top height retrieved were compared with brightness temperature of AIRS for channel 760 (900.56 cm-1, 11. 1 µm) and cirrus reflectance of MODIS cloud product. And cloud top height retrieved was compared with cloud top height from MODIS. Results show that the brightness temperature spectra simulated were basically consistent with AIRS observation under the condition of retrieval in the 650~1150 cm-1 band. It means that CART can be used to simulate AIRS brightness temperature spectra. The retrieved cirrus parameters are consistent with brightness temperature of AIRS for channel 11. 1 µm with low brightness temperature corresponding to large cirrus optical thickness and high cloud top height. And the retrieved cirrus parameters are consistent with cirrus reflectance of MODIS cloud product with high cirrus reflectance corresponding to large cirrus optical thickness and high cloud top height. Correlation coefficient of brightness temperature between retrieved cloud top height and MODIS cloud top height was relatively high. They are mostly located in the range of 8. 5~11.5 km, and their probability distribution trend is approximately identical. CART model is feasible to retrieve cirrus properties, and the retrieval is reliable.

Salinity and spectral reflectance of soils

NASA Technical Reports Server (NTRS)

Szilagyi, A.; Baumgardner, M. F.

1991-01-01

The basic spectral response related to the salt content of soils in the visible and reflective IR wavelengths is analyzed in order to explore remote sensing applications for monitoring processes of the earth system. The bidirectional reflectance factor (BRF) was determined at 10 nm of increments over the 520-2320-nm spectral range. The effect of salts on reflectance was analyzed on the basis of 162 spectral measurements. MSS and TM bands were simulated within the measured spectral region. A strong relationship was found in variations of reflectance and soil characteristics pertaining to salinization and desalinization. Although the individual MSS bands had high R-squared values and 75-79 percent of soil/treatment combinations were separable, there was a large number of soil/treatment combinations not distinguished by any of the four highly correlated MSS bands under consideration.

Discrimination of Fritillary according to geographical origin with Fourier transform infrared spectroscopy and two-dimensional correlation IR spectroscopy.

PubMed

Hua, Rui; Sun, Su-Qin; Zhou, Qun; Noda, Isao; Wang, Bao-Qin

2003-09-19

Fritillaria is a traditional Chinese herbal medicine for eliminating phlegm and relieving a cough with a long history in China and some other Asian countries. The objective of this study is to develop a nondestructive and accurate method to discriminate Fritillaria of different geographical origins, which is a troublesome work by existing analytical methods. We conducted a systematic study on five kinds of Fritillaria by Fourier transform infrared spectroscopy, second derivative infrared spectroscopy, and two-dimensional (2D) correlation infrared spectroscopy under thermal perturbation. Because Fritillaria consist of a large amount of starch, the conventional IR spectra of different Fritillaria only have very limited spectral feature differences. Based on these differences, we can separate different Fritillaria to a limited extent, but this method was deemed not very practical. The second derivative IR spectra of Fritillaria could enhance spectrum resolution, amplify the differences between the IR spectra of different Fritillaria, and provide some dissimilarity in their starch content, when compared with the spectrum of pure starch. Finally, we applied thermal perturbation to Fritillaria and analyzed the resulting spectra by the 2D correlation method to distinguish different Fritillaria easily and clearly. The distinction of very similar Fritillaria was possible because the spectral resolution was greatly enhanced by the 2D correlation spectroscopy. In addition, with the dynamic information of molecular structure provided by 2D correlation IR spectra, we studied the differences in the stability of active components of Fritillaria. The differences embodied mainly on the intensity ratio of the auto-peak at 985 cm(-1) and other auto-peaks. The 2D correlation IR spectroscopy (2D IR) of Fritillaria can be a new and powerful method to discriminate Fritillaria.

Phytosynthesis and Characterization of Silver Nanoparticles Using Callus of JATROPHA CURCAS: a Biotechnological Approach

NASA Astrophysics Data System (ADS)

Demissie, A. G.; Lele, S. S.

2013-06-01

The present study reports a rapid plant-based biosynthesis of silver nanoparticles using callus extract of Jatropha curcas L. The particle size and morphological analyses were carried out using Zetasizer, SEM, TEM. The physicochemical properties were monitored using UV-Vis spectroscopic, IR and DSC. The formation of silver nanoparticle was confirmed by using UV-Vis spectrophotometer and absorbance peaks at 421 nm. The silver nanoparticle was found to be a negatively charged with size ranging from 2 nm to 50 nm. The morphology of the nanoparticle is uniformly spherical and has a dispersion ratio of 0.14. The physicochemical study using DSC indicated significant thermal stability and crystalline nature of the nanoparticle. This intracellular biosynthesis of silver nanoparticles is simple, cheap and eco-friendly than other mechanical and chemical approaches.

Microwave mediated synthesis of ZnS spherical nanoparticles for IR optical ceramics

NASA Astrophysics Data System (ADS)

Ravichandran, D.; Wharton, T.; Devan, B.; Korenstein, R.; Tustison, R.; Komarneni, S.

2011-06-01

The existing material choice for long-wave infrared (LWIR) and semi-active laser domes is multispectral zinc sulfide (ZnS), made by chemical vapor deposition. An alternative route to make more erosion-resistant ZnS could be through hot pressing ZnS nanoparticles into small-grain material. We have attempted to produce ZnS nanoparticles both by microwave and microwave-hydrothermal methods. Microwave route produced ultrahigh purity, homogeneous, well dispersed, and uniformly spherical ZnS nanoparticles. Microwave-hydrothermal route produced equiaxed cubic-faceted nanoparticles. The powder X-ray diffraction patterns of ZnS shows the presence of broad reflections corresponding to the (1 1 1), (2 2 0), and (3 1 1) planes of the cubic crystalline ZnS material. The domain size of the particles estimated from the Debye-Scherrer formula for the main reflection (111) gives a value of 2.9 and 2.5 for the microwave and microwave-hydrothermal methods respectively.

Cellular imaging using temporally flickering nanoparticles.

PubMed

Ilovitsh, Tali; Danan, Yossef; Meir, Rinat; Meiri, Amihai; Zalevsky, Zeev

2015-02-04

Utilizing the surface plasmon resonance effect in gold nanoparticles enables their use as contrast agents in a variety of applications for compound cellular imaging. However, most techniques suffer from poor signal to noise ratio (SNR) statistics due to high shot noise that is associated with low photon count in addition to high background noise. We demonstrate an effective way to improve the SNR, in particular when the inspected signal is indistinguishable in the given noisy environment. We excite the temporal flickering of the scattered light from gold nanoparticle that labels a biological sample. By preforming temporal spectral analysis of the received spatial image and by inspecting the proper spectral component corresponding to the modulation frequency, we separate the signal from the wide spread spectral noise (lock-in amplification).

A Comparison of Analytical and Data Preprocessing Methods for Spectral Fingerprinting

PubMed Central

LUTHRIA, DEVANAND L.; MUKHOPADHYAY, SUDARSAN; LIN, LONG-ZE; HARNLY, JAMES M.

2013-01-01

Spectral fingerprinting, as a method of discriminating between plant cultivars and growing treatments for a common set of broccoli samples, was compared for six analytical instruments. Spectra were acquired for finely powdered solid samples using Fourier transform infrared (FT-IR) and Fourier transform near-infrared (NIR) spectrometry. Spectra were also acquired for unfractionated aqueous methanol extracts of the powders using molecular absorption in the ultraviolet (UV) and visible (VIS) regions and mass spectrometry with negative (MS−) and positive (MS+) ionization. The spectra were analyzed using nested one-way analysis of variance (ANOVA) and principal component analysis (PCA) to statistically evaluate the quality of discrimination. All six methods showed statistically significant differences between the cultivars and treatments. The significance of the statistical tests was improved by the judicious selection of spectral regions (IR and NIR), masses (MS+ and MS−), and derivatives (IR, NIR, UV, and VIS). PMID:21352644

Application of spectroscopic methods (FT-IR, Raman, ECD and NMR) in studies of identification and optical purity of radezolid

NASA Astrophysics Data System (ADS)

Michalska, Katarzyna; Gruba, Ewa; Mizera, Mikołaj; Lewandowska, Kornelia; Bednarek, Elżbieta; Bocian, Wojciech; Cielecka-Piontek, Judyta

2017-08-01

In the presented study, N-{[(5S)-3-(2-fluoro-4‧-{[(1H-1,2,3-triazol-5-ylmethyl)amino]methyl}biphenyl-4-yl)-2-oxo-1,3-oxazolidin-5-yl]methyl}acetamide (radezolid) was synthesized and characterized using FT-IR, Raman, ECD and NMR. The aim of this work was to assess the possibility of applying classical spectral methods such as FT-IR, Raman, ECD and NMR spectroscopy for studies on the identification and optical purity of radezolid. The experimental interpretation of FT-IR and Raman spectra of radezolid was conducted in combination with theoretical studies. Density functional theory (DFT) with the B3LYP hybrid functional was used for obtaining radezolid spectra. Full identification was carried out by COSY, 1H {13C} HSQC and 1H {13C} HMBC experiments. The experimental NMR chemical shifts and spin-spin coupling constants were compared with theoretical calculations using the DFT method and B3LYP functional employing the 6-311 ++G(d,p) basis set and the solvent polarizable continuum model (PCM). The experimental ECD spectra of synthesized radezolid were compared with experimental spectra of the reference standard of radezolid. Theoretical calculations enabled us to conduct HOMO and LUMO analysis and molecular electrostatic potential maps were used to determine the active sites of microbiologically active form of radezolid enantiomer. The relationship between results of ab initio calculations and knowledge about chemical-biological properties of S-radezolid and other oxazolidinone derivatives are also discussed.

The Problem of Spectral Mimicry of Supergiants

NASA Astrophysics Data System (ADS)

Klochkova, V. G.; Chentsov, E. L.

2018-01-01

The phenomenon of spectral mimicry refers to the fact that hypergiants and post-AGB supergiants—stars of different masses in fundamentally different stages of their evolution—have similar optical spectra, and also share certain other characteristics (unstable extended atmospheres, expanding dust-gas envelopes, high IR excesses). As a consequence, it is not always possible to distinguish post-AGB stars from hypergiants based on individual spectral observations in the optical. Examples of spectral mimicry are analyzed using uniform, high-quality spectral material obtained on the 6-m telescope of the Special Astrophysical Observatory in the course of long-term monitoring of high-luminosity stars. It is shown that unambiguously resolving the mimicry problem for individual stars requires the determination of a whole set of parameters: luminosity, wind parameters, spectral energy distribution, spectral features, velocity field in the atmosphere and circumstellar medium, behavior of the parameters with time, and the chemical composition of the atmosphere.

Dynamics of polymer nanoparticles and chains.

NASA Astrophysics Data System (ADS)

Streletzky, Kiril; McKenna, John; Hillier, Gerry

2006-10-01

We present a Dynamic Light Scattering study of transport properties of the polymer chains and nanoparticles made out of the same starting solution. The spectra of both systems are highly non-exponential requiring a spectral time moment analysis. Our findings indicate the existence of several modes of relaxation in both systems. The comparison of the mean relaxation rates and diffusion coefficients of the different modes in two systems under good solvent conditions will be reported. Temperature sensitivity of the polymer nanoparticles and its possible applications in pharmaceutical, coatings, and petroleum industries will also be discussed.

Multichannel Dynamic Fourier-Transform IR Spectrometer

NASA Astrophysics Data System (ADS)

Balashov, A. A.; Vaguine, V. A.; Golyak, Il. S.; Morozov, A. N.; Khorokhorin, A. I.

2017-09-01

A design of a multichannel continuous scan Fourier-transform IR spectrometer for simultaneous recording and analysis of the spectral characteristics of several objects is proposed. For implementing the design, a multi-probe fiber is used, constructed from several optical fibers connected into a single optical connector and attached at the output of the interferometer. The Fourier-transform spectrometer is used as a signal modulator. Each fiber is individually mated with an investigated sample and a dedicated radiation detector. For the developed system, the radiation intensity of the spectrometer is calculated from the condition of the minimum spectral resolution and parameters of the optical fibers. Using the proposed design, emission spectra of a gas-discharge neon lamp have been recorded using a single fiber 1 mm in diameter with a numerical aperture NA = 0.22.

IR-IR Conformation Specific Spectroscopy of Na+(Glucose) Adducts

NASA Astrophysics Data System (ADS)

Voss, Jonathan M.; Kregel, Steven J.; Fischer, Kaitlyn C.; Garand, Etienne

2018-01-01

We report an IR-IR double resonance study of the structural landscape present in the Na+(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na+(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctive Na+ coordination. [Figure not available: see fulltext.

Multiple-frame IR photo-recorder KIT-3M

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roos, E; Wilkins, P; Nebeker, N

2006-05-15

This paper reports the experimental results of a high-speed multi-frame infrared camera which has been developed in Sarov at VNIIEF. Earlier [1] we discussed the possibility of creation of the multi-frame infrared radiation photo-recorder with framing frequency about 1 MHz. The basis of the photo-recorder is a semiconductor ionization camera [2, 3], which converts IR radiation of spectral range 1-10 micrometers into a visible image. Several sequential thermal images are registered by using the IR converter in conjunction with a multi-frame electron-optical camera. In the present report we discuss the performance characteristics of a prototype commercial 9-frame high-speed IR photo-recorder.more » The image converter records infrared images of thermal fields corresponding to temperatures ranging from 300 C to 2000 C with an exposure time of 1-20 {micro}s at a frame frequency up to 500 KHz. The IR-photo-recorder camera is useful for recording the time evolution of thermal fields in fast processes such as gas dynamics, ballistics, pulsed welding, thermal processing, automotive industry, aircraft construction, in pulsed-power electric experiments, and for the measurement of spatial mode characteristics of IR-laser radiation.« less

Antimicrobial and anticancer efficacy of antineoplastic agent capped gold nanoparticles.

PubMed

Selvaraj, V; Grace, A Nirmala; Alagar, M; Hamerton, I

2010-04-01

Synthesis of thioguanine (TG)-capped Au nanoparticles (Au@TG) and their enhanced in vitro antimicrobial and anticancer efficacy against Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, E. coli, Aspergillus fumigatus, Aspergillus niger and Hep2 cancer cell (Human epidermiod cell) have been reported. The nature of binding between 6-TG and the gold nanoparticles via complexation is investigated using ultraviolet-visible spectrum, cyclic voltammetry, transmission electron microscopy, fluorescence and Fourier transform infrared (FT-IR) spectroscopy. The present experimental studies suggests that Au@TG are more potential than TG towards antimicrobial and anticancer activities. Hence, gold nanoparticles have the potential to be used as effective carriers for anticancer drug.

Fourier Transform Infrared Spectroscopy (FT-IR) and Simple Algorithm Analysis for Rapid and Non-Destructive Assessment of Developmental Cotton Fibers.

PubMed

Liu, Yongliang; Kim, Hee-Jin

2017-06-22

With cotton fiber growth or maturation, cellulose content in cotton fibers markedly increases. Traditional chemical methods have been developed to determine cellulose content, but it is time-consuming and labor-intensive, mostly owing to the slow hydrolysis process of fiber cellulose components. As one approach, the attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy technique has also been utilized to monitor cotton cellulose formation, by implementing various spectral interpretation strategies of both multivariate principal component analysis (PCA) and 1-, 2- or 3-band/-variable intensity or intensity ratios. The main objective of this study was to compare the correlations between cellulose content determined by chemical analysis and ATR FT-IR spectral indices acquired by the reported procedures, among developmental Texas Marker-1 (TM-1) and immature fiber ( im ) mutant cotton fibers. It was observed that the R value, CI IR , and the integrated intensity of the 895 cm -1 band exhibited strong and linear relationships with cellulose content. The results have demonstrated the suitability and utility of ATR FT-IR spectroscopy, combined with a simple algorithm analysis, in assessing cotton fiber cellulose content, maturity, and crystallinity in a manner which is rapid, routine, and non-destructive.

Far-Ir Spectroscopy of Neutral Gas Phase Peptides: Signatures from Combined Experiments and Simulations

NASA Astrophysics Data System (ADS)

Mahé, Jérôme; Gaigeot, Marie-Pierre; Bakker, Daniël; Jaeqx, Sander; Rijs, Anouk

2016-06-01

Within the past two decades, action vibrational spectroscopy has become an almost routine experimental method to probe the structures of molecules and clusters in the gas phase (neutral and ions). Such experiments are mainly performed in the 1000-4000 wn fingerprint regions. Though successful in many respects, these spectral domains can be however restrictive in the information provided, and sometimes reach limitations for unravelling structures without ambiguity. In a collaborative work with the group of Dr A.M. Rijs (FELIX laboratory, Radbout University, The Netherlands) we have launched a new strategy where the far-IR/Tera-Hertz domain (100-800 wn domain) is experimentally probed for neutral gas phase molecules. Our group in Paris apply finite temperature DFT-based molecular dynamics (DFT-MD) simulations in order to unravel the complex signatures arising in the far-IR domain, and provide an unambiguous assignment both of the structural conformation of the gas phase molecules (taking into account the experimental conditions) and an understanding of the spectral signatures/fingerprints. We will discuss our experimental and theoretical investigations on two neutral peptides in the 100-800 wn far-IR spectral domain, i.e. Z-Ala6 and PheGly dipeptide, that represent two systems which definitive conformational assignment was not possible without the far IR signatures. We will also present our very recent results on the Phe-X peptide series, where X stands for Gly, Ala, Pro, Val, Ser, Cys, combining experiments and DFT-MD simulations, providing a detailed understanding of the vibrational fingerprints in the far-IR domain. In all exemples, we will show how DFT-MD simulations is the proper theoretical tool to account for vibrational anharmonicities and mode couplings, of prime importance in the far-IR domain. References : J. Mahé, S. Jaeqx, A.M. Rijs, M.P. Gaigeot, Phys. Chem. Chem. Phys., 17 :25905 (2015) S. Jaeqx, J. Oomens, A. Cimas, M.P. Gaigeot, A.M. Rijs, Angew

Simple synthetic route for hydroxyapatite colloidal nanoparticles via a Nd:YAG laser ablation in liquid medium

NASA Astrophysics Data System (ADS)

Mhin, Sung Wook; Ryu, Jeong Ho; Kim, Kang Min; Park, Gyeong Seon; Ryu, Han Wool; Shim, Kwang Bo; Sasaki, Takeshi; Koshizaki, Naoto

2009-08-01

Pulsed laser ablation (PLA) in liquid medium was successfully employed to synthesize hydroxyapatite (HAp) colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the HAp nanoparticles were investigated in detail. The obtained HAp nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were studied in terms of the explosive ejection mechanism by investigating the change of the surface morphology on target. The stoichiometry and bonding properties were studied by using XPS, FT-IR and Raman spectroscopy. A molar ratio of Ca/P of the prepared HAp nanoparticles was more stoichiometric than the value reported in the case of ablation in vacuum.

Strong vibronic coupling effects in polarized IR spectra of the hydrogen bond in N-methylthioacetamide crystals

NASA Astrophysics Data System (ADS)

Flakus, Henryk T.; Śmiszek-Lindert, Wioleta; Stadnicka, Katarzyna

2007-06-01

This paper presents the investigation results of the polarized IR spectra of the hydrogen bond in crystals of N-methylthioacetamide. The spectral studies were preceded by the determination of the crystal X-ray structure. The spectra were measured at 283 K and at 77 K by a transmission method, using polarized light. Theoretical analysis of the results concerned the linear dichroic effects, the H/D isotopic and temperature effects, observed in the solid-state IR spectra of the hydrogen and of the deuterium bond at the frequency ranges of the νN-H and the νN-D bands, respectively. The main spectral properties of the crystals can be interpreted satisfactorily in terms of the simple quantitative theory of the IR spectra of the hydrogen bond, i.e., the " strong-coupling" theory on the basis of the hydrogen bond centrosymmetric dimer model. The spectra revealed that the strongest vibrational exciton coupling involved the closely spaced hydrogen bonds, each belonging to a different chain of associated N-methylthioacetamide molecules. The crystal spectral properties, along with an abnormal H/D isotopic effect in the spectra, were found to be strongly influenced by vibronic coupling mechanisms in these dimers. These mechanisms were considered as responsible for the activation in IR of the totally symmetric proton stretching vibrations in the dimers. On analyzing the spectra of isotopically diluted crystalline samples of N-methylthioacetamide, it was proved that a non-random distribution of the protons and deuterons took place in the hydrogen bond lattices. In an individual hydrogen-bonded chain in the crystals distribution of the hydrogen isotope atoms H and D was fully random. The H/D isotopic " self-organization" mechanism, of a vibronic nature, involved a pair of hydrogen bonds from a unit cell, where each hydrogen bond belonged to a different chain of the associated molecules.

Adaptive optics high-resolution IR spectroscopy with silicon grisms and immersion gratings

NASA Astrophysics Data System (ADS)

Ge, Jian; McDavitt, Daniel L.; Chakraborty, Abhijit; Bernecker, John L.; Miller, Shane

2003-02-01

The breakthrough of silicon immersion grating technology at Penn State has the ability to revolutionize high-resolution infrared spectroscopy when it is coupled with adaptive optics at large ground-based telescopes. Fabrication of high quality silicon grism and immersion gratings up to 2 inches in dimension, less than 1% integrated scattered light, and diffraction-limited performance becomes a routine process thanks to newly developed techniques. Silicon immersion gratings with etched dimensions of ~ 4 inches are being developed at Penn State. These immersion gratings will be able to provide a diffraction-limited spectral resolution of R = 300,000 at 2.2 micron, or 130,000 at 4.6 micron. Prototype silicon grisms have been successfully used in initial scientific observations at the Lick 3m telescope with adaptive optics. Complete K band spectra of a total of 6 T Tauri and Ae/Be stars and their close companions at a spectral resolution of R ~ 3000 were obtained. This resolving power was achieved by using a silicon echelle grism with a 5 mm pupil diameter in an IR camera. These results represent the first scientific observations conducted by the high-resolution silicon grisms, and demonstrate the extremely high dispersing power of silicon-based gratings. New discoveries from this high spatial and spectral resolution IR spectroscopy will be reported. The future of silicon-based grating applications in ground-based AO IR instruments is promising. Silicon immersion gratings will make very high-resolution spectroscopy (R > 100,000) feasible with compact instruments for implementation on large telescopes. Silicon grisms will offer an efficient way to implement low-cost medium to high resolution IR spectroscopy (R ~ 1000-50000) through the conversion of existing cameras into spectrometers by locating a grism in the instrument's pupil location.

IR spectral studies of the formation of prebiological organic molecules in ion-bombarded ices

NASA Astrophysics Data System (ADS)

Hudson, R.; Moore, M.

To better understand the formation of C- and CN-containing molecules in cold cosmic environments we have performed a variety of processing experiments on icy mixtures. We will discuss details of condensed-phase synthetic pathways for several acids, alcohols, and aldehydes. For N2 -rich ices containing CH4 , we will show that several CN-bonded acids are easily formed. We will compare carbonic and formic acid production in H O-, CO- and CO2 -dominated ices.2 Condensed-phase pathways for the synthesis of several alcohols including methanol and ethylene glycol, along with several aldehydes including formaldehyde and acetaldehyde, will be discussed. While warming irradiated ices, IR spectra help track the formation of new species from, for example, radical or acid-base reactions, and the loss of species due to vaporization. These experiments demonstrate that condensed-phase reactions lead to cometary and interstellar molecules of varying volatilities. Several newly synthesized species are particularly relevant to recent radio detections, and are of high interest to astronomers and astrobiologists. This research is funded through NRA 344-33-01 and 344-02-57.

Pixelated coatings and advanced IR coatings

NASA Astrophysics Data System (ADS)

Pradal, Fabien; Portier, Benjamin; Oussalah, Meihdi; Leplan, Hervé

2017-09-01

Reosc developed pixelated infrared coatings on detector. Reosc manufactured thick pixelated multilayer stacks on IR-focal plane arrays for bi-spectral imaging systems, demonstrating high filter performance, low crosstalk, and no deterioration of the device sensitivities. More recently, a 5-pixel filter matrix was designed and fabricated. Recent developments in pixelated coatings, shows that high performance infrared filters can be coated directly on detector for multispectral imaging. Next generation space instrument can benefit from this technology to reduce their weight and consumptions.

Fast Fourier Transform IR Characterization of Epoxy GY Systems Crosslinked with Aliphatic and Cycloaliphatic EH Polyamine Adducts

PubMed Central

Nikolic, Goran; Zlatkovic, Sasa; Cakic, Milorad; Cakic, Suzana; Lacnjevac, Caslav; Rajic, Zoran

2010-01-01

The use of fast FT-IR spectroscopy as a sensitive method to estimate a change of the crosslinking kinetics of epoxy resin with polyamine adducts is described in this study. A new epoxy formulation based on the use of polyamine adducts as the hardeners was analyzed. Crosslinking reactions of the different stoichiometric mixtures of the unmodified GY250 epoxy resin with the aliphatic EH606 and the cycloaliphatic EH637 polyamine adducts were studied using mid FT-IR spectroscopic techniques. As the crosslinking proceeded, the primary amine groups in polyamine adduct are converted to secondary and the tertiary amines. The decrease in the IR band intensity of epoxy groups at about 915 cm−1, as well as at about 3,056 cm−1, was observed due to process. Mid IR spectral analysis was used to calculate the content of the epoxy groups as a function of crosslinking time and the crosslinking degree of resin. The amount of all the epoxy species was estimated from IR spectra to changes during the crosslinking kinetics of epichlorhydrin. PMID:22315562

Spectroscopic characterization of enzymatic flax retting: Factor analysis of FT-IR and FT-Raman data

NASA Astrophysics Data System (ADS)

Archibald, D. D.; Henrikssen, G.; Akin, D. E.; Barton, F. E.

1998-06-01

Flax retting is a chemical, microbial or enzymatic process which releases the bast fibers from the stem matrix so they can be suitable for mechanical processing before spinning into linen yarn. This study aims to determine the vibrational spectral features and sampling methods which can be used to evaluate the retting process. Flax stems were retted on a small scale using an enzyme mixture known to yield good retted flax. Processed stems were harvested at various time points in the process and the retting was evaluated by conventional methods including weight loss, color difference and Fried's test, a visual ranking of how the stems disintegrate in hot water. Spectroscopic measurements were performed on either whole stems or powders of the fibers that were mechanically extracted from the stems. Selected regions of spectra were baseline and amplitude corrected using a variant of the multiplicative signal correction method. Principal component regression and partial least-squares regression with full cross-validation were used to determine the spectral features and rate of spectral transformation by regressing the spectra against the retting time in hours. FT-Raman of fiber powders and FT-IR reflectance of whole stems were the simplest and most precise methods for monitoring the retting transformation. Raman tracks the retting by measuring the decrease in aromatic signal and subtle changes in the C-H stretching vibrations. The IR method uses complex spectral features in the fingerprint and carbonyl region, many of which are due to polysaccharide components. Both spectral techniques monitor the retting process with greater precision than the reference method.

IR-IR Conformation Specific Spectroscopy of Na +(Glucose) Adducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voss, Jonathan M.; Kregel, Steven J.; Fischer, Kaitlyn C.

Here in this paper we report an IR-IR double resonance study of the structural landscape present in the Na +(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na +(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctivemore » Na+ coordination.« less

IR-IR Conformation Specific Spectroscopy of Na +(Glucose) Adducts

DOE PAGES

Voss, Jonathan M.; Kregel, Steven J.; Fischer, Kaitlyn C.; ...

2017-09-27

Here in this paper we report an IR-IR double resonance study of the structural landscape present in the Na +(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na +(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctivemore » Na+ coordination.« less

Individual and collective modes of surface magnetoplasmon in thiolate-protected silver nanoparticles studied by MCD spectroscopy

NASA Astrophysics Data System (ADS)

Yao, Hiroshi; Shiratsu, Taisuke

2016-05-01

) spectroscopy. The samples examined are decanethiol (DT)-, azobenzenethiol (ABT)-, and ABT/DT mixed-monolayer-protected Ag nanoparticles. ABT-protected Ag nanoparticles are somewhat aggregated and thus exhibit a broad, collective mode of plasmonic absorption, whereas other samples with highly-dispersed nanoparticles show an individual mode of LSPR absorption. In all Ag nanoparticles, a derivative-like MCD signal is observed under an applied magnetic field of 1.6 T, which can be explained in terms of two circular modes of magnetoplasmon caused by the increase (or decrease) in the Lorentz force imparted on the free electrons that oscillate in the left (or right) circular orbits in the nanosphere. For the Ag nanoparticles exhibiting an individual LSPR mode, in particular, simultaneous deconvolution analysis of UV-vis absorption and MCD spectra reveal that (i) the amplitude of the magnetoplasmonic component with lower frequency (ω-), resulting from the reduction in the confinement strength of collective electrons by the Lorentz force, is stronger than that with a higher frequency (ω+) (ii) the accurate shift or cyclotron frequency between two magnetoplasmonic modes (ωc = ω+ - ω-) is size-dependent, and presents a very large value with implications for the apparent enhancement of the local magnetic-field in the Ag nanoparticles. These results strongly suggest that the Ag-thiolate layer or Ag-S bonding on the nanoparticle surface plays a significant role in the MO enhancement. Electronic supplementary information (ESI) available: EDX spectroscopic analysis of various Ag nanoparticle samples; MCD signals normalized to absorbance for the Ag(DT)L and Ag(DT)S samples; deconvolution of UV-vis absorption and MCD spectra using three Lorentzian components; IR spectral changes upon photoisomerization; thermal cis-to-trans relaxation of azobenzene in the Ag(ABT) sample; UV-vis absorption spectra of Ag nanoparticle samples in the presence/absence of a magnetic field of 1.6 T. See DOI: 10

Spectral Signature of Radiative Forcing by East Asian Dust-Soot Mixture

NASA Astrophysics Data System (ADS)

Zhu, A.; Ramanathan, V.

2007-12-01

The Pacific Dust Experiment (PACDEX) provides the first detailed sampling of dust-soot mixtures from the western Pacific to the eastern Pacific Ocean. The data includes down and up spectral irradiance, mixing state of dust and soot, and other aerosol properties. This study attempts to simulate the radiative forcing by dust-soot mixtures during the experimental period. The MODTRAN band model was employed to investigate the spectral signatures of solar irradiance change induced by aerosols at moderate spectral resolutions. For the short wave band (300-1100nm) used in this study, the reduction of downward irradiance at surface by aerosols greatly enhances with increasing wavelength in the UV band (300-400nm), reaches a maximum in the blue band, then gradually decreases toward the red band. In the near-IR band (700-1100nm), irradiance reduction by aerosols shows great fluctuations in the band with center wavelength at around 940nm, 820nm, 720nm, 760nm, 690nm, where the aerosol effect is overwhelmed by the water vapor and O2 absorptions. The spectral pattern of irradiance reduction varies for different aerosol species. The maximum reduction lies at around 450nm for soot, and shifting to about 490nm for East Asian mineral dust. It's worth noting that although soot aerosols reduce more irradiance than East Asian dust in the UV and blue band, the impact of dust to the irradiance exceeds that by soot at the longer wavelength band (i.e. around 550nm). The reduction of irradiance by East Asian dust (soot) in the UV band, visible band, and near-IR accounts for about 6% (10%), 56% (64%), and 38% (26%) of total irradiance reduction. As large amount of soot aerosols are involved during the long range transport of East Asian dust, the optical properties of dust aerosols are modified with different mixing state with soot, the spectral pattern of the irradiance reduction will be changed. The study of aerosol forcing at moderate spectral resolutions has the potential application for

Orientation of N-benzoyl glycine on silver nanoparticles: SERS and DFT studies

NASA Astrophysics Data System (ADS)

Parameswari, A.; Asath, R. Mohamed; Premkumar, R.; Benial, A. Milton Franklin

2017-05-01

Surface enhanced Raman scattering (SERS) studies of N-benzoyl glycine (NBG) adsorbed on silver nanoparticles (AgNPs) was studied by experimental and density functional theory (DFT) approach. Single crystals of NBG were prepared using slow evaporation method. The AgNPs were prepared and characterized. The DFT/ B3PW91 method with LanL2DZ basis set was used to optimize the molecular structure of NBG and NBG adsorbed on silver cluster. The calculated and observed vibrational frequencies were assingned on the basis of potential energy distribution calculation. The reduced band gap value was obtained for NBG adsorbed on silver nanoparticles from the frontier molecular orbitals analysis. Natural bond orbital analysis was carried out to inspect the intra-molecular stabilization interactions, which are responsible for the bio activity and nonlinear optical property of the molecule. The spectral analysis was also evidenced that NBG would adsorb tilted orientation on the silver surface over the binding sites such as lone pair electron of N atom in amine group and through phenyl ring π system.

Fitting the spectral energy distributions of galaxies with CIGALE : Code Investigating GALaxy Emission

NASA Astrophysics Data System (ADS)

Giovannoli, E.; Buat, V.

2013-03-01

We use the code CIGALE (Code Investigating Galaxies Emission: Burgarella et al. 2005; Noll et al. 2009) which provides physical information about galaxies by fitting their UV (ultraviolet)-to-IR (infrared) spectral energy distribuition (SED). CIGALE is based on the use of a UV-optical stellar SED plus a dust IR-emitting component. We study a sample of 136 Luminous Infrared Galaxies (LIRGs) at z˜0.7 in the ECDF-S previously studied in Giovannoli et al. (2011). We focus on the way the empirical Dale & Helou (2002) templates reproduce the observed SEDs of the LIRGs. Fig. 1 shows the total infrared luminosity (L IR ) provided by CIGALE using the 64 templates (x axis) and using 2 templates (y axis) representative of the whole sample. Despite the larger dispersion when only 1 or 2 Herschel data are available, the agreement between both values is good with Δ log L IR = 0.0013 ± 0.045 dex. We conclude that 2 IR SEDs can be used alone to determine the L IR of LIRGs at z˜0.7 in an SED-fitting procedure.

Gold nanoparticles and electroporation impose both separate and synergistic radiosensitizing effects in HT-29 tumor cells: an in vitro study.

PubMed

Rezaee, Zohre; Yadollahpour, Ali; Bayati, Vahid; Negad Dehbashi, Fereshteh

2017-01-01

Radiation therapy (RT) is the gold standard treatment for more than half of known tumors. Despite recent improvements in RT efficiency, the side effects of ionizing radiation (IR) in normal tissues are a dose-limiting factor that restricts higher doses in tumor treatment. One approach to enhance the efficiency of RT is the application of radiosensitizers to selectively increase the dose at the tumor site. Gold nanoparticles (GNPs) and electroporation (EP) have shown good potential as radiosensitizers for RT. This study aims to investigate the sensitizing effects of EP, GNPs, and combined GNPs-EP on the dose enhancement factor (DEF) for 6 MV photon energy. Radiosensitizing effects of EP, GNPs, and combinations of GNPs-EP were comparatively investigated in vitro for intestinal colon cancer (HT-29) and Chinese hamster ovary (CHO) cell lines by MTT assay and colony formation assay at 6 MV photon energy in six groups: IR (control group), GNPs+IR, GNPs (24 h)+IR, EP+IR, GNPs+EP+IR, and GNPs (24 h)+EP+IR. Treatment of both cell lines with EP, GNPs, and combined GNPs-EP significantly enhanced the response of cells to irradiation. However, the HT-29 showed higher DEF values for all groups. In addition, the DEF value for HT-29 cells for GNPs+IR, GNPs (24 h)+IR, EP+IR, GNPs+EP+IR, and GNPs (24 h)+EP+IR was, respectively, 1.17, 1.47, 1.36, 2.61, and 2.89, indicating synergistic radiosensitizing effect for the GNPs (24 h)+EP+IR group. Furthermore, the synergistic effect was observed just for HT-29 tumor cell lines. Combined GNPs-EP protocols induced synergistic radiosensitizing effect in HT-29 cells, and the effect is also tumor specific. This combined therapy can be beneficially used for the treatment of intrinsically less radiosensitive tumors.

Bioselective synthesis of gold nanoparticles from diluted mixed Au, Ir, and Rh ion solution by Anabaena cylindrica

NASA Astrophysics Data System (ADS)

Rochert, Anna S.; Rösken, Liz M.; Fischer, Christian B.; Schönleber, Andreas; Ecker, Dennis; van Smaalen, Sander; Geimer, Stefan; Wehner, Stefan

2017-11-01

Over the last years, an environmentally friendly and economically efficient way of nanoparticle production has been found in the biosynthesis of metal nanoparticles by bacteria and cyanobacteria. In this study, Anabaena cylindrica, a non-toxic cyanobacterium, is deployed in a diluted ionic aqueous mixture of equal concentrations of gold, iridium, and rhodium, of 0.1 mM each, for the selective biosynthesis of metal nanoparticles (NPs). To analyze the cyanobacterial metal uptake, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometry (ICP-MS) were applied. Only gold can be found in crystalline and nanoparticle form inside the cells of A. cylindrica, and it is the only metal for which ICP-MS analyses show a rapid decrease of the concentration in the culture medium. A slight decrease of rhodium and none of iridium was observed in the evaluated timeline of 51 h. The average diameter size of the emerging gold nanoparticles increased over the first few days, but is found to be below 10 nm even after more than 2 days. A new evaluation method was used to determine the spatially resolved distribution of the nanoparticles inside the cyanobacterial cells. This new method was also used to analyze TEM images from earlier studies of A. cylindrica and Anabaena sp., both incubated with an overall concentration of 0.8 mM Au3+ to compare the metal uptake. A. cylindrica was found to be highly selective towards the formation of gold nanoparticles in the presence of rhodium and iridium.

Spectral Properties of Gas-phase Condensed Fullerene-like Carbon Nanoparticles from Far-ultraviolet to Infrared Wavelengths

NASA Astrophysics Data System (ADS)

Jäger, C.; Mutschke, H.; Henning, Th.; Huisken, F.

2008-12-01

Carbon solids are ubiquitous material in interstellar space. However, the formation pathway of carbonaceous matter in astrophysical environments, as well as in terrestrial gas-phase condensation reactions, is not yet understood. Laser ablation of graphite in different quenching gas atmospheres, such as pure He, He/H2, and He/H2O at varying pressures, is used to synthesize very small, fullerene-like carbon nanoparticles. The particles are characterized by very small diameters between 1 and 4 nm and a disturbed onion-like structure. The soot particles extracted from the condensation zone obviously represent a very early stage of particle condensation. The spectral properties have been measured from the far-ultraviolet (FUV; λ = 120 nm) to the mid-infrared (MIR; λ = 15 μm). The seedlike soot particles show strong absorption bands in the 3.4 μm range. The profile and the intensity pattern of the 3.4 μm band of the diffuse interstellar medium can be well reproduced by the measured 3.4 μm profile of the condensed particles; however, all the carbon which is left to form solids is needed to fit the intensity of the interstellar bands. In contrast to the assumption that onion-like soot particles could be the carriers of the interstellar ultraviolet (UV) bump, our very small onion-like carbon nanoparticles do not show distinct UV bands due to (π-π*) transitions.

Rapid discrimination of extracts of Chinese propolis and poplar buds by FT-IR and 2D IR correlation spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Yan-Wen; Sun, Su-Qin; Zhao, Jing; Li, Yi; Zhou, Qun

2008-07-01

The extract of Chinese propolis (ECP) has recently been adulterated with that of poplar buds (EPB), because most of ECP is derived from the poplar plant, and ECP and EPB have almost identical chemical compositions. It is very difficult to differentiate them by using the chromatographic methods such as high performance liquid chromatography (HPLC) and gas chromatography (GC). Therefore, how to effectively discriminate these two mixtures is a problem to be solved urgently. In this paper, a rapid method for discriminating ECP and EPB was established by the Fourier transform infrared (FT-IR) spectra combined with the two-dimensional infrared correlation (2D IR) analysis. Forty-three ECP and five EPB samples collected from different areas of China were analyzed by the FT-IR spectroscopy. All the ECP and EPB samples tested show similar IR spectral profiles. The significant differences between ECP and EPB appear in the region of 3000-2800 cm -1 of the spectra. Based on such differences, the two species were successfully classified with the soft independent modeling of class analogy (SIMCA) pattern recognition technique. Furthermore, these differences were well validated by a series of temperature-dependent dynamic FT-IR spectra and the corresponding 2D IR plots. The results indicate that the differences in these two natural products are caused by the amounts of long-chain alkyl compounds (including long-chain alkanes, long-chain alkyl esters and long chain alkyl alcohols) in them, rather than the flavonoid compounds, generally recognized as the bioactive substances of propolis. There are much more long-chain alkyl compounds in ECP than those in EPB, and the carbon atoms of the compounds in ECP remain in an order Z-shaped array, but those in EPB are disorder. It suggests that FT-IR and 2D IR spectroscopy can provide a valuable method for the rapid differentiation of similar natural products, ECP and EPB. The IR spectra could directly reflect the integrated chemical

Dynamics of a Room Temperature Ionic Liquid in Supported Ionic Liquid Membranes vs the Bulk Liquid: 2D IR and Polarized IR Pump-Probe Experiments.

PubMed

Shin, Jae Yoon; Yamada, Steven A; Fayer, Michael D

2017-01-11

Supported ionic liquid membranes (SILMs) are membranes that have ionic liquids impregnated in their pores. SILMs have been proposed for advanced carbon capture materials. Two-dimensional infrared (2D IR) and polarization selective IR pump-probe (PSPP) techniques were used to investigate the dynamics of reorientation and spectral diffusion of the linear triatomic anion, SeCN - , in poly(ether sulfone) (PES) membranes and room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf 2 ). The dynamics in the bulk EmimNTf 2 were compared to its dynamics in the SILM samples. Two PES membranes, PES200 and PES30, have pores with average sizes, ∼300 nm and ∼100 nm, respectively. Despite the relatively large pore sizes, the measurements reveal that the reorientation of SeCN - and the RTIL structural fluctuations are substantially slower in the SILMs than in the bulk liquid. The complete orientational randomization, slows from 136 ps in the bulk to 513 ps in the PES30. 2D IR measurements yield three time scales for structural spectral diffusion (SSD), that is, the time evolution of the liquid structure. The slowest decay constant increases from 140 ps in the bulk to 504 ps in the PES200 and increases further to 1660 ps in the PES30. The results suggest that changes at the interface propagate out and influence the RTIL structural dynamics even more than a hundred nanometers from the polymer surface. The differences between the IL dynamics in the bulk and in the membranes suggest that studies of bulk RTIL properties may be poor guides to their use in SILMs in carbon capture applications.

Studying the morphological features of plasma treated silver and PEGylated silver nanoparticles: antibacterial activity

NASA Astrophysics Data System (ADS)

Waseem, M.; Awan, T.; Yasin, H. M.; Rehman, N. U.

2018-03-01

A strategy to treat the silver and PEGylated silver nanoparticles with plasma was being purposed. Oil in water (o/w) microemulsion method was used for the synthesis of Ag nanoparticles (AgNPs). Polyethylene glycol (PEG) having molecular weight 600 was used to coat the surface of AgNPs. Optical emission spectroscopy (OES) was used to characterize the plasma and it is noted that plasma treatment is useful to modify the structural characteristic of silver nanoparticles. The nanoparticles were treated with helium-oxygen mixture plasma, generated in plasma needle at atmospheric pressure. Both AgNPs and PEGylated AgNPs before and after plasma treatment were characterized by x-rays diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The crystallite size of silver nanoparticles after the treatment of plasma decreases from 71 nm to 27 nm. The SEM micrographs show that the size of Ag nanoparticles was nearly 118 nm whereas the thickness of the silver needle was around 135 nm. All the characteristics IR bands associated to the silver nanoparticles were detected. The FTIR spectrum also support the accumulation of OH radicals in the plasma treated samples. The samples before and after plasma treatment were screened against Gram positive (Bacillus Subtilis and Staphylococcus Aureus) and Gram negative (Escherichia Coli and Pseudomonas Aeruginosa) bacteria. The promising response was detected when plasma treated PEGylated AgNPs was tested against bacterial strains.

Noninvasive Thermal Ablation of Osteomyelitis-Causing Bacteria using Functionalized Nanoparticles

DTIC Science & Technology

2012-03-01

2008). One alternative approach to antibiotics includes the use of near infrared ( IR ) radiation to thermally kill pathogenic organisms (Kam, 2005...Zharov, 2006). Whereas near IR wavelengths pass harmlessly through the human body, they are known to heat gold nanoshells to high temperatures (>70°C...nanoparticles both alone and complexed with PlyCB (Fig. 8). Task 3. Determine depth of IR radiation penetration and range of thermal damage. (months 11- 15

Dual-Enzyme Characteristics of Polyvinylpyrrolidone-Capped Iridium Nanoparticles and Their Cellular Protective Effect against H2O2-Induced Oxidative Damage.

PubMed

Su, Hua; Liu, Dan-Dan; Zhao, Meng; Hu, Wei-Liang; Xue, Shan-Shan; Cao, Qian; Le, Xue-Yi; Ji, Liang-Nian; Mao, Zong-Wan

2015-04-22

Polyvinylpyrrolidone-stabilized iridium nanoparticles (PVP-IrNPs), synthesized by the facile alcoholic reduction method using abundantly available PVP as protecting agents, were first reported as enzyme mimics showing intrinsic catalase- and peroxidase-like activities. The preparation procedure was much easier and more importantly, kinetic studies found that the catalytic activity of PVP-IrNPs was comparable to previously reported platinum nanoparticles. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterization indicated that PVP-IrNPs had the average size of approximately 1.5 nm and mainly consisted of Ir(0) chemical state. The mechanism of PVP-IrNPs' dual-enzyme activities was investigated using XPS, Electron spin resonance (ESR) and cytochrome C-based electron transfer methods. The catalase-like activity was related to the formation of oxidized species Ir(0)@IrO2 upon reaction with H2O2. The peroxidase-like activity originated from their ability acting as electron transfer mediators during the catalysis cycle, without the production of hydroxyl radicals. Interestingly, the protective effect of PVP-IrNPs against H2O2-induced cellular oxidative damage was investigated in an A549 lung cancer cell model and PVP-IrNPs displayed excellent biocompatibility and antioxidant activity. Upon pretreatment of cells with PVP-IrNPs, the intracellular reactive oxygen species (ROS) level in response to H2O2 was decreased and the cell viability increased. This work will facilitate studies on the mechanism and biomedical application of nanomaterials-based enzyme mimic.

Effect of silver nanoparticles on the spectral luminescent properties of a gelatin film

NASA Astrophysics Data System (ADS)

Efendiev, T. Sh.; Kruchenok, J. V.; Rubinov, A. N.

2013-03-01

We studied the absorption and fluorescence spectra of a rhodamine 6G-activated gelatin film of thickness 10 μm, with and without silver nanoparticles. We observed that doping the film with nanoparticles of diameter 5 nm leads to an increase in the intensity of the absorption spectrum by a factor of 1.17 and its short-wavelength shift (~1.5 nm), while the intensity of the fluorescence spectrum increases by a factor of ~2.

Synthesis and structural, optical and thermal properties of CdS:Zn2+ nanoparticles

NASA Astrophysics Data System (ADS)

Muruganandam, S.; Anbalagan, G.; Murugadoss, G.

2014-12-01

Undoped and Zn (1-5, 10 %) -doped CdS nanoparticles were successfully synthesized by chemical method and polyvinylpyrrolidone was used as capping agent. The morphology and crystalline structure of the samples were studied by transmission electron microscopy and X-ray diffraction. The average particle size of the spherical nanoparticles determined by these techniques was of the order of 2.5-6 nm. The functional groups of the capping agent on CdS:Zn2+ surface were identified by FT-IR study. The band gap of the nanoparticles was calculated using UV-visible absorption spectra and the result showed that the band gap values were dramatically blue shifted from the bulk CdS. The optimum concentration of the doping ions was selected through absorption study. Photoluminescence of the CdS:Zn2+ nanoparticle showed strong blue and green emission. The thermal properties of the nanoparticles were analyzed by thermogravimetric-differential thermal analysis.

Development of new magnetic nanoparticles: Oligochitosan obtained by γ-rays and -coated Fe3O4 nanoparticles

NASA Astrophysics Data System (ADS)

Le Thi, Thao Nguyen; Nguyen, Thi Hiep; Hoang, Dong Quy; Tran, Tuong, Vi; Nguyen, Ngoc Thuy; Nguyen, Dai Hai

2017-11-01

Oligochitosan (OCS) have been utilized as a potential bioactive material for improving food quality and human health. In this study, superparamagnetic iron oxide (Fe3O4) nanoparticles were originally coated with OCS irradiated by gamma rays for their possible biomedical applications. The formation of Fe3O4@OCS was characterized by Fourier transform infrared (FT-IR), X-ray diffraction patterns (XRD), energy dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TGA). In addition, the superparamagnetic properties and sizes and morphologies of Fe3O4 and Fe3O4@OCS nanoparticles were demonstrated by vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM), respectively. These results indicated that Fe3O4@OCS nanoparticles still maintained their superparamagnetic properties after polymeric coating, and were nearly spherical in shape with average diameter of 14.4 ± 0.31 nm, compared with 11.8 ± 0.52 nm of bare Fe3O4 nanoparticles, respectively. As a result, Fe3O4@OCS nanoparticles may serve as a promising platform for the development of new magnetic materials, which could be useful for biomedical applications.

Synthesis procedure optimization and characterization of europium (III) tungstate nanoparticles

NASA Astrophysics Data System (ADS)

Rahimi-Nasrabadi, Mehdi; Pourmortazavi, Seied Mahdi; Ganjali, Mohammad Reza; Reza Banan, Ali; Ahmadi, Farhad

2014-09-01

Taguchi robust design as a statistical method was applied for the optimization of process parameters in order to tunable, facile and fast synthesis of europium (III) tungstate nanoparticles. Europium (III) tungstate nanoparticles were synthesized by a chemical precipitation reaction involving direct addition of europium ion aqueous solution to the tungstate reagent solved in an aqueous medium. Effects of some synthesis procedure variables on the particle size of europium (III) tungstate nanoparticles were studied. Analysis of variance showed the importance of controlling tungstate concentration, cation feeding flow rate and temperature during preparation of europium (III) tungstate nanoparticles by the proposed chemical precipitation reaction. Finally, europium (III) tungstate nanoparticles were synthesized at the optimum conditions of the proposed method. The morphology and chemical composition of the prepared nano-material were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, FT-IR spectroscopy and fluorescence.

Up-conversion multiwave (White) luminescence in the visible spectral range under excitation by IR laser diodes in the active BaY2F8:Yb3+,Pr3+ medium

NASA Astrophysics Data System (ADS)

Pushkar', A. A.; Uvarova, T. V.; Kiiko, V. V.

2011-08-01

The possibilities of occupying high-lying 4 f states of Pr3+ ions in the active BaY2F8:Yb3+,Pr3+ medium according to the photon avalanche and step-by-step sensitization mechanisms are compared. It is shown that the photon avalanche is unlikely to occur in the BaY2F8:Yb3+,Pr3+ crystal. The multiband luminescence spectra in the visible spectral range (white emission) under single- and multiwave pumping of BaY2F8:Yb3+,Pr3+ crystal by IR laser diodes are reported.

Analysis of cosmetic residues on a single human hair by ATR FT-IR microspectroscopy

NASA Astrophysics Data System (ADS)

Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Naranitad, Suwimol; Ekgasit, Sanong

2018-05-01

In this work, ATR FT-IR spectra of single human hair and cosmetic residues on hair surface are successfully collected using a homemade dome-shaped Ge μIRE accessary installed on an infrared microscope. By collecting ATR spectra of hairs from the same person, the spectral patterns are identical and superimposed while different spectral features are observed from ATR spectra of hairs collected from different persons. The spectral differences depend on individual hair characteristics, chemical treatments, and cosmetics on hair surface. The "Contact-and-Collect" technique that transfers remarkable materials on the hair surface to the tip of the Ge μIRE enables an identification of cosmetics on a single hair. Moreover, the differences between un-split and split hairs are also studied in this report. These highly specific spectral features can be employed for unique identification or for differentiation of hairs based on the molecular structures of hairs and cosmetics on hairs.

Green way genesis of silver nanoparticles using multiple fruit peels waste and its antimicrobial, anti-oxidant and anti-tumor cell line studies

NASA Astrophysics Data System (ADS)

Naganathan, Kiruthika; Thirunavukkarasu, Somanathan

2017-04-01

Green synthesis of silver nanoparticles (SNP) opens a new path to kill and prevent various infectious diseases and also tumor. In this study, we have synthesized silver nanoparticles using multiple fruit peel waste (pomegranate, orange, banana and apple (POBA)). The primarily nanoparticles formation has been confirmed by the color change. The synthesized SNP were analyzed by various physicochemical techniques such as UV- Visible spectroscopy, x-ray diffraction (XRD), fourier transform infra red (FT-IR) spectroscopy and transmission electron microscope (TEM). The formation of SNP was confirmed by its absorbance peak observed at 430 nm in UV-Visible spectrum. Further, the obtained SNP were identified by XRD and TEM, respectively to know the crystalline nature and size and shape of the particles. The activities of SNP were checked with human pathogens (Salmonella, E.coli and Pseudomonas), plant pathogen (Fusarium) and marine pathogen (Aeromonas hydrophila) and also studied the scavenging effect and anticancer properties against MCF-7 cell lines. This studies proves that the SNP prepared from fruit waste peel extract approach appears extremely fast, cost efficient, eco-friendly and alternative for conventional methods of SNP synthesis to promote the usage of these nanoparticles in medicinal application.

Hydrothermal assisted growth of CdSe nanoparticles and study on its dielectric properties

NASA Astrophysics Data System (ADS)

Jamble, Shweta N.; Ghoderao, Karuna P.; Kale, Rohidas B.

2017-11-01

In this work, we have synthesized cadmium selenide (CdSe) nanoparticles by using cadmium chloride (CdCl2) as cadmium ion and sodium selenosulfate (Na2SeSO3) as selenium ion sources through a simple, convenient and cost-effective hydrothermal route at 180 °C temperature for 24 h. Aqueous ammonia was employed as a complex reagent to adjust the pH of the solution. Structural analysis of the obtained product was carried out by using x-ray diffractometer, which revealed that the final product has a cubic structure of CdSe with average crystallite size 13.15 nm. The cauliflower-like CdSe nanostructures were confirmed from the scanning electron microscopy and high-resolution transmission electron microscopy. EDS analysis indicates that the obtained product has a good elemental stoichiometric ratio. The electron diffraction pattern reveals the polycrystalline nature of CdSe. From UV-visible absorption spectral analysis, the optical energy bandgap of CdSe nanoparticles was found to be 1.90 eV. XPS spectra presented Cd 3d3/2, Cd 3d5/2 and Se 3d3/2 peaks at 411.04, 404.29 and 53.52 eV respectively. The CdSe nanoparticles exhibit photoluminescence with two distinct emission bands at 632 nm and 720 nm. FTIR study was used towards the understanding of the formation mechanism and bonding on the surface of the resulting nanoparticles. The dielectric properties of a pelletized sample of CdSe nanoparticles were carried out at room temperature.

Spectroscopic studies of ozone in cryosolutions: FT-IR spectra of 16O3 in liquid nitrogen, oxygen, argon and krypton

NASA Astrophysics Data System (ADS)

Bulanin, Kirill M.; Bulanin, Michael O.; Rudakova, Aida V.; Kolomijtsova, Tatiana D.; Shchepkin, Dmitrij N.

2018-03-01

We have measured and interpreted the IR spectra of ozone dissolved in liquid nitrogen, oxygen, argon, and krypton in the 650-4700 cm-1 spectral region at 79-117 K. Frequency shifts, band intensities and bandshapes of 22 spectral features of soluted ozone were analyzed. The bands of the A1 symmetry have a complex contour and possess an excess intensity with respect to the value of the purely vibrational transition moment. It was found that this effect is related to the manifestation of the Coriolis interaction. The bandshape distortion manifests itself as an additional intensity from the side of the B1 symmetry band being an intensity source in the case of the Coriolis interaction.

FT-IR spectroscopic, thermal analysis of human urinary stones and their characterization

NASA Astrophysics Data System (ADS)

Selvaraju, R.; Raja, A.; Thiruppathi, G.

2015-02-01

In the present study, FT-IR, XRD, TGA-DTA spectral methods have been used to investigate the chemical compositions of urinary calculi. Multi-components of urinary calculi such as calcium oxalate, hydroxyl apatite, struvite and uric acid have been studied. The chemical compounds are identified by FT-IR spectroscopic technique. The mineral identification was confirmed by powder X-ray diffraction patterns as compared with JCPDS reported values. Thermal analysis techniques are considered the best techniques for the characterization and detection of endothermic and exothermic behaviors of the urinary stones. The percentages of each hydrate (COM and COD) are present together, in the presences of MAPH or UA. Finally, the present study suggests that the Urolithiasis is significant health problem in children, and is very common in some parts of the world, especially in India. So that present study is so useful and helpful to the scientific community for identification of latest human health problems and their remedies using spectroscopic techniques.

Synthesis, spectral, thermal and antimicrobial studies of transition metal complexes of 14-membered tetraaza[N4] macrocyclic ligand

NASA Astrophysics Data System (ADS)

Shankarwar, Sunil G.; Nagolkar, Bhagwat B.; Shelke, Vinod A.; Chondhekar, Trimbak K.

2015-06-01

A series of metal complexes of Mn(II), Co(II), Ni(II), Cu(II), have been synthesized with newly synthesized biologically active macrocyclic ligand. The ligand was synthesized by condensation of β-diketone 1-(4-chlorophenyl)-3-(2-hydroxyphenyl)propane-1,3-dione and o-phenylene diamine. All the complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, 1H-NMR, UV-Vis spectroscopy and mass spectroscopy. From the analytical data, stoichiometry of the complexes was found to be 1:2 (metal:ligand). Thermal behavior (TG/DTA) and kinetic parameters suggest more ordered activated state in complex formation. All the complexes are of high spin type and six coordinated. On the basis of IR, electronic spectral studies and magnetic behavior, an octahedral geometry has been assigned to these complexes. The antibacterial and antifungal activities of the ligand and its metal complexes, has been screened in vitro against Staphylococcus aureus, Escherichia coli and Aspergillus niger, Trichoderma respectively.

Tin-decorated ruthenium nanoparticles: a way to tune selectivity in hydrogenation reaction

NASA Astrophysics Data System (ADS)

Bonnefille, Eric; Novio, Fernando; Gutmann, Torsten; Poteau, Romuald; Lecante, Pierre; Jumas, Jean-Claude; Philippot, Karine; Chaudret, Bruno

2014-07-01

Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity.Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00791c

Spectral, thermal, kinetic, molecular modeling and eukaryotic DNA degradation studies for a new series of albendazole (HABZ) complexes

NASA Astrophysics Data System (ADS)

El-Metwaly, Nashwa M.; Refat, Moamen S.

2011-01-01

This work represents the elaborated investigation for the ligational behavior of the albendazole ligand through its coordination with, Cu(II), Mn(II), Ni(II), Co(II) and Cr(III) ions. Elemental analysis, molar conductance, magnetic moment, spectral studies (IR, UV-Vis and ESR) and thermogravimetric analysis (TG and DTG) have been used to characterize the isolated complexes. A deliberate comparison for the IR spectra reveals that the ligand coordinated with all mentioned metal ions by the same manner as a neutral bidentate through carbonyl of ester moiety and NH groups. The proposed chelation form for such complexes is expected through out the preparation conditions in a relatively acidic medium. The powder XRD study reflects the amorphous nature for the investigated complexes except Mn(II). The conductivity measurements reflect the non-electrolytic feature for all complexes. In comparing with the constants for the magnetic measurements as well as the electronic spectral data, the octahedral structure was proposed strongly for Cr(III) and Ni(II), the tetrahedral for Co(II) and Mn(II) complexes but the square-pyramidal for the Cu(II) one. The thermogravimetric analysis confirms the presence or absence of water molecules by any type of attachments. Also, the kinetic parameters are estimated from DTG and TG curves. ESR spectrum data for Cu(II) solid complex confirms the square-pyramidal state is the most fitted one for the coordinated structure. The albendazole ligand and its complexes are biologically investigated against two bacteria as well as their effective effect on degradation of calf thymus DNA.

A statistical evaluation of spectral fingerprinting methods using analysis of variance and principal component analysis

USDA-ARS?s Scientific Manuscript database

Six methods were compared with respect to spectral fingerprinting of a well-characterized series of broccoli samples. Spectral fingerprints were acquired for finely-powdered solid samples using Fourier transform-infrared (IR) and Fourier transform-near infrared (NIR) spectrometry and for aqueous met...

[Research on the measurement of flue-dust concentration in Vis, IR spectral region].

PubMed

Sun, Xiao-gang; Tang, Hong; Yuan, Gui-bin

2008-10-01

In the measurement of flue-dust concentration based on the transmission method, the dependent model algorithm was used to invert the flue-dust concentration in the visible, infrared and visible-infrared spectral regions respectively. By the analysis and comparison of the accuracy, linearity and sensitivity of the inversion flue-dust concentration, the optimal spectral region was determined. Meanwhile, the influence of the water droplet with different size distribution and volume concentration was simulated, and a method was proposed which has advantages of simplicity, rapidity, and suitability for on line measurement. Simulation experiments illustrate that the flue-dust concentration can be inverted very well in the visible-infrared spectral region, and it is feasible to use the ratio of the constrained light extinction method to overcome the influence of water droplet. The inverse results all remain satisfactory when 2% stochastic noise is added to the value of the light extinction.

Laboratory mid-IR spectra of equilibrated and igneous meteorites. Searching for observables of planetesimal debris

NASA Astrophysics Data System (ADS)

de Vries, B. L.; Skogby, H.; Waters, L. B. F. M.; Min, M.

2018-06-01

Meteorites contain minerals from Solar System asteroids with different properties (like size, presence of water, core formation). We provide new mid-IR transmission spectra of powdered meteorites to obtain templates of how mid-IR spectra of asteroidal debris would look like. This is essential for interpreting mid-IR spectra of past and future space observatories, like the James Webb Space Telescope. First we present new transmission spectra of powdered ordinary chondrite, pallasite and HED meteorites and then we combine them with already available transmission spectra of chondrites in the literature, giving a total set of 64 transmission spectra. In detail we study the spectral features of minerals in these spectra to obtain measurables used to spectroscopically distinguish between meteorite groups. Being able to differentiate between dust from different meteorite types means we can probe properties of parent bodies, like their size, if they were wet or dry and if they are differentiated (core formation) or not. We show that the transmission spectra of wet and dry chondrites, carbonaceous and ordinary chondrites and achondrite and chondrite meteorites are distinctly different in a way one can distinguish in astronomical mid-IR spectra. Carbonaceous chondrites type < 3 (aqueously altered) show distinct features of hydrated silicates (hydrosilicates) compared to the olivine and pyroxene rich ordinary chondrites (dry and equilibrated meteorites). Also the iron concentration of the olivine in carbonaceous chondrites differs from ordinary chondrites, which can be probed by the wavelength peak position of the olivine spectral features. The transmission spectra of chondrites (not differentiated) are also strongly different from the achondrite HED meteorites (meteorites from differentiated bodies like 4 Vesta), where the latter show much stronger pyroxene signatures. The two observables that spectroscopically separate the different meteorites groups (and thus the different

IR spectroscopic studies in microchannel structures

NASA Astrophysics Data System (ADS)

Guber, A. E.; Bier, W.

1998-06-01

By means of the various microengineering methods available, microreaction systems can be produced among others. These microreactors consist of microchannels, where chemical reactions take place under defined conditions. For optimum process control, continuous online analytics is envisaged in the microchannels. For this purpose, a special analytical module has been developed. It may be applied for IR spectroscopic studies at any point of the microchannel.

Studying the nonlinearity in Sonic IR NDE

NASA Astrophysics Data System (ADS)

Yu, Qiuye; Obeidat, Omar; Han, Xiaoyan

2017-02-01

Sonic IR Imaging combines pulsed ultrasound excitation and infrared imaging to detect defects in materials. The sound pulse causes rubbing due to non--unison motion between faces of defects, and infrared sensors image the temperature map over the target to identify defects. It works in various materials, including metal/metal alloy, ceramics, and composite materials. Its biggest advantage is that it's a fast, wide area NDE technique. It takes only a fraction of a second or a few seconds, depending on the thermal properties of the target, for one test over a few square feet. However, due to the nonlinearity in the coupling between the ultrasound transducer and the target, the repeatability has been an issue, which affects its application. In this paper, we present our study on this issue in Sonic IR.

pH dependent conjugation of Ibuprofen to PEGylated nanoparticles

NASA Astrophysics Data System (ADS)

Bharti, Shivani; Jain, Shikshita; Kaur, Gurvir; Gupta, Shikha; Tripathi, S. K.

2018-04-01

In this paper, Ibuprofen, a water insoluble drug was covalently attached to PEGylated nanoparticles. Firstly, Surface functionalization of water dispersed core/shell nanoparticles had been done using hydrophilic polymer PEG-diamine. Therefore, PEGylated nanoparticles contain NH2 groups over the surface of nanoparticles and can be used for the further attachment of biomolecules. Ibuprofen was covalently loaded on the PEGylated core/shell nanoparticles using carbodiimide reaction. The synthesis had been carried out under two different pH environments, as the solubility of Ibuprofen is pH dependent. The resultant samples were characterized using UV-Vis absorption and FT-IR spectroscopy. The results strongly suggest the successful chemical conjugation of Ibuprofen to PEGylated nanoparticles in aqueous media and they could be further used for drug delivery applications.

Purification, immobilization, and characterization of nattokinase on PHB nanoparticles.

PubMed

Deepak, Venkataraman; Pandian, Suresh babu Ram Kumar; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

2009-12-01

In this study, nattokinase was purified from Bacillus subtilis using ion exchange chromatography and immobilized upon polyhydroxybutyrate (PHB) nanoparticles. A novel strain isolated from industrial dairy waste was found to synthesize polyhydroxyalkanoates (PHA) and the strain was identified as Brevibacterium casei SRKP2. PHA granules were extracted from 48 h culture and the FT-IR analysis characterized them as PHB, a natural biopolymer from B. casei. Nanoprecipitation by solvent displacement technique was used to synthesize PHB nanoparticles. PHB nanoparticles were characterized using transmission electron microscopy and particle size ranged from 100-125 nm. Immobilization of nattokinase upon PHB nanoparticles resulted in a 20% increase in the enzyme activity. Immobilization also contributed to the enhanced stability of the enzyme. Moreover, the activity was completely retained on storage at 4 degrees C for 25 days. The method has proven to be highly simple and can be implemented to other enzymes also.

Silica-coated manganite and Mn-based ferrite nanoparticles: a comparative study focused on cytotoxicity

NASA Astrophysics Data System (ADS)

Kaman, Ondřej; Dědourková, Tereza; Koktan, Jakub; Kuličková, Jarmila; Maryško, Miroslav; Veverka, Pavel; Havelek, Radim; Královec, Karel; Turnovcová, Karolína; Jendelová, Pavla; Schröfel, Adam; Svoboda, Ladislav

2016-04-01

Magnetic oxide nanoparticles provide a fascinating tool for biological research and medicine, serving as contrast agents, magnetic carriers, and core materials of theranostic systems. Although the applications rely mostly on iron oxides, more complex oxides such as perovskite manganites may provide a much better magnetic performance. To assess the risk of their potential use, in vitro toxicity of manganite nanoparticles was thoroughly analysed and compared with another prospective system of Mn-Zn ferrite nanoparticles. Magnetic nanoparticles of La0.63Sr0.37MnO3 manganite were prepared by two distinct methods, namely the molten salt synthesis and the traditional sol-gel route, whereas nanoparticles of Mn0.61Zn0.42Fe1.97O4 ferrite, selected as a comparative material, were synthesized by a new procedure under hydrothermal conditions. Magnetic cores were coated with silica and, moreover, several samples of manganite nanoparticles with different thicknesses of silica shell were prepared. The size-fractionated and purified products were analysed using transmission electron microscopy, dynamic light scattering, measurement of the zeta-potential dependence on pH, IR spectroscopy, and SQUID magnetometry. The silica-coated products with accurately determined concentration by atomic absorption spectroscopy were subjected to a robust evaluation of their cytotoxicity by four different methods, including detailed analysis of the concentration dependence of toxicity, analysis of apoptosis, and experiments on three different cell lines. The results, comparing two manganese-containing systems, clearly indicated superior properties of the Mn-Zn ferrite, whose silica-coated nanoparticles show very limited toxic effects and thus constitute a promising material for bioapplications.

Development of a Near-Ir Cavity Enhanced Absorption Spectrometer for the Detection of Atmospheric Oxidation Products and Organoamines

NASA Astrophysics Data System (ADS)

Eddingsaas, Nathan C.; Jewell, Breanna; Thurnherr, Emily

2014-06-01

An estimated 10,000 to 100,000 different compounds have been measured in the atmosphere, each one undergoes many oxidation reactions that may or may not degrade air quality. To date, the fate of even some of the most abundant hydrocarbons in the atmosphere is poorly understood. One difficulty is the detection of atmospheric oxidation products that are very labile and decompose during analysis. To study labile species under atmospheric conditions, a highly sensitive, non-destructive technique is needed. Here we describe a near-IR incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) setup that we are developing to meet this end. We have chosen to utilize the near-IR, where vibrational overtone absorptions are observed, due to the clean spectral windows and better spectral separation of absorption features. In one spectral window we can simultaneously and continuously monitor the composition of alcohols, hydroperoxides, and carboxylic acids in an air mass. In addition, we have used our CEAS setup to detect organoamines. The long effective path length of CEAS allows for low detection limits, even of the overtone absorption features, at ppb and ppt levels.

IR Bandwidth and Crystal Thickness Effects on THG Efficiency and Temporal Shaping of Quasi-Rectangular UV Pulses: Part II - Incident IR Ripple

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolton, Paul R.; Limborg-Deprey, Cecile; /SLAC

We have investigated the effect of incident ir spectral bandwidth and crystal thickness, on uv pulses produced by third harmonic generation (THG) in a crystal pair. Our focus is on the third harmonic generation efficiency and longitudinal uv intensity profile parameters of SNLO predictions that are evaluated for three incident ir spectral bandwidths and a range of crystal thicknesses. These results represent a continuation of earlier work in which the effects of the same selected ir bandwidths and range of crystal thicknesses were investigated using a pair of BBO Type I crystals in a simplistic geometry for which the longitudinalmore » intensity plateau has a zero slope, 'flattop' profile. The current work is distinguished from the previous work by an imposed ripple on the ir intensity longitudinal profile and constitutes a portion of a Part II effort to which we have made reference. As with preceding work, all third harmonic data are net results at the exit of the second BBO crystal. Predictions are obtained with the modified SNLO code developed by Arlee Smith at the Sandia National Laboratories. This modification has allowed us to pursue the 'coupled' case in which the output of the first BBO crystal is used as input to the second one. This includes both the fundamental and second harmonic light. Defined parameters are consistent with previous work. The presented cases are best results. The criteria for selection of these reported cases are highest THG efficiency combined with minimum intensity ripple in the plateau. The incident ir pulse is quasi-rectangular with an imposed 5.2 % (rms) intensity ripple added to the plateau. The ir pulse bandwidth is centered at 800 nm. Second harmonic generation occurs in the first BBO crystal and THG occurs in the second crystal as a consequence of sum frequency generation. Type I phase matching is used throughout, so that for a negative uniaxial crystal: n{sub 2}{sup e}({theta}) = n{sub 1}{sup o};(SHG) (1.1) 3n{sub 3}{sup 3

A Study of IR Loss Correction Methodologies for Commercially Available Pyranometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Chuck; Andreas, Afshin; Augustine, John

2017-03-24

This presentation provides a high-level overview of a study of IR Loss Connection Methodologies for Commercially Available Pyranometers. The IR Loss Corrections Study is investigating how various correction methodologies work for several makes and models of commercially available pyranometers in common use, both when operated in ventilators with DC fans and without ventilators, as when they are typically calibrated.

Fluorescence multiplexing with time-resolved and spectral discrimination using a near-IR detector.

PubMed

Zhu, Li; Stryjewski, Wieslaw; Lassiter, Suzanne; Soper, Steven A

2003-05-15

We report on the design and performance of a two-color, time-resolved detector for the acquisition of both steady-state and time-resolved fluorescence data acquired in real time during the capillary gel electrophoresis separation of DNA sequencing fragments. The detector consisted of a pair of pulsed laser diodes operating at 680 and 780 nm. The diode heads were coupled directly to single-mode fibers, which were terminated into a single fiber mounted via a FC/PC connector to the detector body. The detector contained a dichroic filter, which directed the dual-laser beams to an objective. The objective focused the laser light into a capillary gel column and also collected the resulting fluorescence emission. The dual-color emission was transmitted through the dichroic and focused onto a multimode fiber (core diameter 50 microm), which carried the luminescence to a pair of single-photon avalanche diodes (SPADs). The emission was sorted spectrally using a second dichroic onto one of two SPADs and isolated using appropriate interference filters (710- or 810-nm channel). The dual-color detector demonstrated a time response of 450 and 510 ps (fwhm) for the 710- and 810-nm channels, respectively. The mass detection limits for two near-IR dye-labeled sequencing primers electrophoresed in a capillary gel column were found to be 7.1 x 10(-21) and 3.2 x 10(-20) mol (SNR = 3) for the 710- and 810-nm detector channels, respectively. In addition, no leakage of luminescence excited at 680 nm was observed in the 810-nm channel or 780-nm excited luminescence into the 710-nm channel. An M13mp18 template was sequenced in a single capillary gel column using a two-color, two-lifetime format. The read length was found to be 650 base pairs for the test template at a calling accuracy of 95.1% using a linear poly(dimethylacrylamide) (POP6) gel column, with the read length determined primarily by the electrophoretic resolution produced by the sieving gel.

Opuntia ficus indica peel derived pectin mediated hydroxyapatite nanoparticles: synthesis, spectral characterization, biological and antimicrobial activities.

PubMed

Gopi, D; Kanimozhi, K; Kavitha, L

2015-04-15

In the present study, we have adapted a facile and efficient green route for the synthesis of HAP nanoparticles using pectin as a template which was extracted from the peel of prickly pear (Opuntia ficus indica) fruits. The concentration of pectin plays a major role in the behavior of crystallinity, purity, morphology as well as biological property of the as-synthesized HAP nanoparticles. The extracted pectin and the as-synthesized nanoparticles were characterized by various analytical techniques. The in vitro apatite formation on the surface of the as-synthesized nanoparticles in simulated body fluid (SBF) for various days showed an enhanced bioactivity. Also, the antimicrobial activity was investigated using various microorganisms. All the results revealed the formation of pure, low crystalline and discrete granular like HAP nanoparticles of size around 25 nm with enhanced biological and antimicrobial activities. Hence the as-synthesized nanoparticles can act as a better bone regenerating material in the field of biomedicine. Copyright © 2015 Elsevier B.V. All rights reserved.

Opuntia ficus indica peel derived pectin mediated hydroxyapatite nanoparticles: Synthesis, spectral characterization, biological and antimicrobial activities

NASA Astrophysics Data System (ADS)

Gopi, D.; Kanimozhi, K.; Kavitha, L.

2015-04-01

In the present study, we have adapted a facile and efficient green route for the synthesis of HAP nanoparticles using pectin as a template which was extracted from the peel of prickly pear (Opuntia ficus indica) fruits. The concentration of pectin plays a major role in the behavior of crystallinity, purity, morphology as well as biological property of the as-synthesized HAP nanoparticles. The extracted pectin and the as-synthesized nanoparticles were characterized by various analytical techniques. The in vitro apatite formation on the surface of the as-synthesized nanoparticles in simulated body fluid (SBF) for various days showed an enhanced bioactivity. Also, the antimicrobial activity was investigated using various microorganisms. All the results revealed the formation of pure, low crystalline and discrete granular like HAP nanoparticles of size around 25 nm with enhanced biological and antimicrobial activities. Hence the as-synthesized nanoparticles can act as a better bone regenerating material in the field of biomedicine.

Characterization of Organosolv Lignins using Thermal and FT-IR Spectroscopic Analysis

Treesearch

Rhea J. Sammons; David P. Harper; Nicole Labbe; Joseph J. Bozell; Thomas Elder; Timothy G. Rials

2013-01-01

A group of biomass-derived lignins isolated using organosolv fractionation was characterized by FT-IR spectral and thermal property analysis coupled with multivariate analysis. The principal component analysis indicated that there were significant variations between the hardwood, softwood, and grass lignins due to the differences in syringyl and guaiacyl units as well...

Theoretical and experimental studies of hydrogen adsorption and desorption on Ir surfaces

DOE PAGES

Kaghazchi, Payam; Jacob, Timo; Chen, Wenhua; ...

2013-06-03

Here, we report adsorption and desorption of hydrogen on planar Ir(210) and faceted Ir(210), consisting of nanoscale {311} and (110) facets, by means of temperature programmed desorption (TPD) and density functional theory (DFT) in combination with the ab initio atomistic thermodynamics approach. TPD spectra show that only one H 2 peak is seen from planar Ir(210) at all coverages whereas a single H 2 peak is observed at around 440 K (F1) at fractional monolayer (ML) coverage and an additional H 2 peak appears at around 360 K (F2) at 1 ML coverage on faceted Ir(210), implying structure sensitivity inmore » recombination and desorption of hydrogen on faceted Ir(210) versus planar Ir(210), but no evidence is found for size effects in recombination and desorption of hydrogen on faceted Ir(210) for average facet sizes of 5-14 nm. Calculations indicate that H prefers to bind at the two-fold short-bridge sites of the Ir surfaces. In addition, we studied the stability of the Ir surfaces in the presence of hydrogen at different H coverages through surface free energy plots as a function of the chemical potential, which is also converted to a temperature scale. Moreover, the calculations revealed the origin of the two TPD peaks of H 2 from faceted Ir(210): F1 from desorption of H 2 on {311} facets while F2 from desorption of H 2 on (110) facets.« less

Spitzer-IRS Spectroscopic Studies of Oxygen-Rich Asymptotic Giant Branch Star and Red Supergiant Star Dust Properties

NASA Astrophysics Data System (ADS)

Sargent, Benjamin A.; Srinivasan, Sundar; Speck, Angela; Volk, Kevin; Kemper, Ciska; Reach, William T.; Lagadec, Eric; Bernard, Jean-Philippe; McDonald, Iain; Meixner, Margaret

2015-01-01

We analyze the dust emission features seen in Spitzer Space Telescope Infrared Spectrograph (IRS) spectra of Oxygen-rich (O-rich) asymptotic giant branch (AGB) and red supergiant (RSG) stars. The spectra come from the Spitzer Legacy program SAGE-Spectroscopy (PI: F. Kemper) and other archival Spitzer-IRS programs. The broad 10 and 20 micron emission features attributed to amorphous dust of silicate composition seen in the spectra show evidence for systematic differences in the centroid of both emission features between O-rich AGB and RSG populations. Radiative transfer modeling using the GRAMS grid of models of AGB and RSG stars suggests that the centroid differences are due to differences in dust properties. We present an update of our investigation of differences in dust composition, size, shape, etc that might be responsible for these spectral differences. We explore how these differences may arise from the different circumstellar environments around RSG and O-rich AGB stars. BAS acknowledges funding from NASA ADAP grant NNX13AD54G.

VLT near- to mid-IR imaging and spectroscopy of the M 17 UC1 - IRS5 region

NASA Astrophysics Data System (ADS)

Chen, Zhiwei; Nürnberger, Dieter E. A.; Chini, Rolf; Jiang, Zhibo; Fang, Min

2015-06-01

Aims: We investigate the surroundings of the hypercompact H ii region M 17 UC1 to probe the physical properties of the associated young stellar objects and the environment of massive star formation. Methods: We use diffraction-limited near-IR (VLT/NACO) and mid-IR (VLT/VISIR) images to reveal the different morphologies at various wavelengths. Likewise, we investigate the stellar and nebular content of the region with VLT/SINFONI integral field spectroscopy with a resolution R ˜ 1500 at H + K bands. Results: Five of the seven point sources in this region show L-band excess emission. A geometric match is found between the H2 emission and near-IR polarized light in the vicinity of IRS5A, and between the diffuse mid-IR emission and near-IR polarization north of UC1. The H2 emission is typical for dense photodissociation regions (PDRs), which are initially far-ultraviolet pumped and repopulated by collisional de-excitation. The spectral types of IRS5A and B273A are B3-B7 V/III and G4-G5 III, respectively. The observed infrared luminosity LIR in the range 1-20 μm is derived for three objects; we obtain 2.0 × 103 L⊙ for IRS5A, 13 L⊙ for IRS5C, and 10 L⊙ for B273A. Conclusions: IRS5 might be a young quadruple system. Its primary star IRS5A is confirmed to be a high-mass protostellar object (˜9 M⊙, ˜1 × 105 yrs); it might have terminated accretion due to the feedback from stellar activities (radiation pressure, outflow) and the expanding H ii region of M 17. The object UC1 might also have terminated accretion because of the expanding hypercompact H ii region, which it ionizes. The disk clearing process of the low-mass young stellar objects in this region might be accelerated by the expanding H ii region. The outflows driven by UC1 are running south-north with its northeastern side suppressed by the expanding ionization front of M 17; the blue-shifted outflow lobe of IRS5A is seen in two types of tracers along the same line of sight in the form of H2 emission

Ultrafast transient absorption studies of hematite nanoparticles: the effect of particle shape on exciton dynamics.

PubMed

Fitzmorris, Bob C; Patete, Jonathan M; Smith, Jacqueline; Mascorro, Xiomara; Adams, Staci; Wong, Stanislaus S; Zhang, Jin Z

2013-10-01

Much progress has been made in using hematite (α-Fe2 O3 ) as a potentially practical and sustainable material for applications such as solar-energy conversion and photoelectrochemical (PEC) water splitting; however, recent studies have shown that the performance can be limited by a very short charge-carrier diffusion length or exciton lifetime. In this study, we performed ultrafast studies on hematite nanoparticles of different shapes to determine the possible influence of particle shape on the exciton dynamics. Nanorice, multifaceted spheroidal nanoparticles, faceted nanocubes, and faceted nanorhombohedra were synthesized and characterized by using SEM and XRD techniques. Their exciton dynamics were investigated by using femtosecond transient absorption (TA) spectroscopy. Although the TA spectral features differ for the four samples studied, their decay profiles are similar, which can be fitted with time constants of 1-3 ps, approximately 25 ps, and a slow nanosecond component extending beyond the experimental time window that was measured (2 ns). The results indicate that the overall exciton lifetime is weakly dependent on the shape of the hematite nanoparticles, even though the overall optical absorption and scattering are influenced by the particle shape. This study suggests that other strategies need to be developed to increase the exciton lifetime or to lengthen the exciton diffusion length in hematite nanostructures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extending Supernova Spectral Templates for Next Generation Space Telescope Observations

NASA Astrophysics Data System (ADS)

Roberts-Pierel, Justin; Rodney, Steven A.; Steven Rodney

2018-01-01

Widely used empirical supernova (SN) Spectral Energy Distributions (SEDs) have not historically extended meaningfully into the ultraviolet (UV), or the infrared (IR). However, both are critical for current and future aspects of SN research including UV spectra as probes of poorly understood SN Ia physical properties, and expanding our view of the universe with high-redshift James Webb Space Telescope (JWST) IR observations. We therefore present a comprehensive set of SN SED templates that have been extended into the UV and IR, as well as an open-source software package written in Python that enables a user to generate their own extrapolated SEDs. We have taken a sampling of core-collapse (CC) and Type Ia SNe to get a time-dependent distribution of UV and IR colors (U-B,r’-[JHK]), and then generated color curves are used to extrapolate SEDs into the UV and IR. The SED extrapolation process is now easily duplicated using a user’s own data and parameters via our open-source Python package: SNSEDextend. This work develops the tools necessary to explore the JWST’s ability to discriminate between CC and Type Ia SNe, as well as provides a repository of SN SEDs that will be invaluable to future JWST and WFIRST SN studies.

Spectral evolution of distributed feedback laser of gold nanoparticles doped solid-state dye laser medium

NASA Astrophysics Data System (ADS)

An, N. T. M.; Lien, N. T. H.; Hoang, N. D.; Nghia, N. T.; Hoa, D. Q.

2017-10-01

Characteristics of suppressed relaxation oscillation of a distributed feedback dye laser (DFDL) based on the energy transfer process in a mixture of spherical gold nanoparticles-doped solid-state polymethylmetacrylate dissolved 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran dye was theoretically and experimentally studied. Single pulse generation regime of the DFDL can be obtained with a suitable gold nanoparticle concentration and ratio of pump power over lasing threshold. Numerical analysis and experimental approach showed that in this regime, the first-pulse laser pulsewidth is rather unchanged while varying the gold nanoparticles concentration in the range of 2.0 × 109-2.0 × 1010 par cm-3. The enhancement of first pulse and the suppression of the secondary pulses by bi-direction energy transfer of spherical gold nanoparticles were experimentally observed.

Quantitative IR microscopy and spectromics open the way to 3D digital pathology.

PubMed

Bobroff, Vladimir; Chen, Hsiang-Hsin; Delugin, Maylis; Javerzat, Sophie; Petibois, Cyril

2017-04-01

Currently, only mass-spectrometry (MS) microscopy brings a quantitative analysis of chemical contents of tissue samples in 3D. Here, the reconstruction of a 3D quantitative chemical images of a biological tissue by FTIR spectro-microscopy is reported. An automated curve-fitting method is developed to extract all intense absorption bands constituting IR spectra. This innovation benefits from three critical features: (1) the correction of raw IR spectra to make them quantitatively comparable; (2) the automated and iterative data treatment allowing to transfer the IR-absorption spectrum into a IR-band spectrum; (3) the reconstruction of an 3D IR-band matrix (x, y, z for voxel position and a 4 th dimension with all IR-band parameters). Spectromics, which is a new method for exploiting spectral data for tissue metadata reconstruction, is proposed to further translate the related chemical information in 3D, as biochemical and anatomical tissue parameters. An example is given with oxidative stress distribution and the reconstruction of blood vessels in tissues. The requirements of IR microscopy instrumentation to propose 3D digital histology as a clinical routine technology is briefly discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alginate/cashew gum nanoparticles for essential oil encapsulation.

PubMed

de Oliveira, Erick F; Paula, Haroldo C B; de Paula, Regina C M

2014-01-01

Alginate/cashew gum nanoparticles were prepared via spray-drying, aiming at the development of a biopolymer blend for encapsulation of an essential oil. Nanoparticles were characterized regarding to their hydrodynamic volume, surface charge, Lippia sidoides essential oil content and release profile, in addition to being analyzed by infrared spectroscopy (FT-IR), thermal analysis (TGA/DSC) and X-ray diffractometry. Nanoparticles in solution were found to have averaged sizes in the range 223-399 nm, and zeta potential values ranging from -30 to -36 mV. Encapsulated oil levels varied from 1.9 to 4.4% with an encapsulation efficiency of up to 55%. The in vitro release profile showed that between 45 and 95% of oil was released within 30-50h. Kinetic studies revealed that release pattern follow a Korsmeyer-Peppas mechanism. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral line narrowing in PPLN OPO devices for 1-μm wavelength doubling

NASA Astrophysics Data System (ADS)

Perrett, Brian J.; Terry, Jonathan A. C.; Mason, Paul D.; Orchard, David A.

2004-12-01

One route to generating mid-infrared (mid-IR) radiation is through a two-stage non-linear conversion process from the near-IR, exploiting powerful neodymium lasers operating at wavelengths close to 1 μm. In the first stage of this process non-linear conversion within a degenerate optical parametric oscillator (OPO) is used to double the wavelength of the 1 μm laser. The resultant 2 μm radiation is then used to pump a second OPO, based on a material such as ZGP, for conversion into the 3 to 5 μm mid-IR waveband. Periodically poled lithium niobate (PPLN) is a useful material for conversion from 1 to 2 μm due to its high non-linear coefficient (deff ~ 16 pm/V) and the long crystal lengths available (up to 50 mm). Slope efficiencies in excess of 40% have readily been achieved using a simple plane-plane resonator when pumped at 10 kHz with 3.5 mJ pulses from a 1.047 μm Nd:YLF laser. However, the OPO output was spectrally broad at degeneracy with a measured full-width-half-maximum (FWHM) linewidth of approximately 65 nm. This output linewidth is significantly broader than the spectral acceptance bandwidth of ZGP for conversion into the mid-IR. In this paper techniques for spectral narrowing the output from a degenerate PPLN OPO are investigated using two passive elements, a diffraction grating and an air spaced etalon. Slope efficiencies approaching 20% have been obtained using the grating in a dog-leg cavity configuration producing spectrally narrow 2 μm output with linewidths as low as 2 nm. A grating-narrowed degenerate PPLN OPO has been successfully used to pump a ZGP OPO.

UV, visible, and near-IR reflectivity data for magnetic soils/rocks from Brazil

NASA Technical Reports Server (NTRS)

Vempati, R. K.; Morris, R. V.; Lauer, H. V., Jr.; Coey, J. M. D.

1991-01-01

The objective is to obtain UV, visible, and near-IR reflectivity spectra for several magnetic Brazilian soils/rocks and compare them to corresponding data for Mars to see if these materials satisfy both magnetic and spectral constraints for Mars. Selected physical properties of the magnetic Brazilian soils/rocks are presented. In general, the spectral features resulting from ferric crystal-field transitions are much better defined in the spectra of the magnetic Brazilian soils/rocks than in Martian spectral data. Presumably, this results from a relatively higher proportion of crystalline ferric oxides for the former. The apparent masking of the spectral signature of maghemite by hematite or goethite for the Brazilian samples implies the magnetic and spectral constraints for Mars can be decoupled. That is, maghemite may be present in magnetically-significant but optically-insignificant amounts compared to crystalline hematite.

Radiative transfer modeling for analyses with Akatsuki/IR2 images

NASA Astrophysics Data System (ADS)

Sato, Takao M.; Satoh, Takehiko; Hashimoto, George L.; Lee, Yeon Joo; Sagawa, Hideo; Kasaba, Yasumasa

2017-10-01

The 2-micron camera (IR2) onboard Japanese Venus orbiter, Akatsuki had regularly observed Venus with four narrow-band filters (1.735, 2.02, 2.26, and 2.32 micron) from the late of March, 2016 until the electronic device was unable to control IR2 on December 9, 2016. For approximately nine months, we accumulated more than 3,000 dayside and nightside images of Venus. The main purposes of analyzing IR2 data are (i) to study the dynamics in the upper, middle, and lower atmosphere with the cloud-tracked winds, (ii) to derive the cloud top altitude with the 2.02 micron channel which is located in a CO2 absorption band, (iii) to deduce CO distribution, which is thought to be a good tracer of the atmospheric circulation below the massive clouds, by utilizing the 2.26 and 2.32 micron channels, and (iv) to investigate aerosol properties of the lower clouds with the 1.735 and 2.26 micron channels. For purposes (ii)-(iv), we have developed a line-by-line based radiative transfer model for generating synthetic radiance at the IR2 channels. For both solar and thermal radiation cases, adding doubling method (Hovenier et al., 2004; Liu and Weng, 2006) is selected for solving multiple scattering by clouds and molecules. We considered a total of eight molecules (H2O, CO2, CO, SO2, HF, HCl, OCS, and N2) and line parameters of the first three molecules are taken from HITEMP10 and those of the others are from HITRAN12. For all considered molecules, their line shapes are modelled as Voigt function with cutoff of 125 cm-1. For CO2, additional modification is done based on Tonkov et al. (1996). A cloud model consisting of four modal cloud particles with a mixture of 75% H2SO4 and 25% H2O is taken from Haus et al. (2013). This model was tested from near-infrared to mid-infrared ranges for the spectral analyses of Venus Express and Venera 15 data, which is useful for interpreting the very limited spectral information such as Akatsuki data. In this presentation, we will show the detail of

Measurement of ablation threshold of oxide-film-coated aluminium nanoparticles irradiated by femtosecond laser pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chefonov, O V; Ovchinnikov, A V; Il'ina, I V

We report the results of experiments on estimation of femtosecond laser threshold intensity at which nanoparticles are removed from the substrate surface. The studies are performed with nanoparticles obtained by femtosecond laser ablation of pure aluminium in distilled water. The attenuation (or extinction, i.e. absorption and scattering) spectra of nanoparticles are measured at room temperature in the UV and optical wavelength ranges. The size of nanoparticles is determined using atomic force microscopy. A new method of scanning photoluminescence is proposed to evaluate the threshold of nanoparticle removal from the surface of a glass substrate exposed to IR femtosecond laser pulsesmore » with intensities 10{sup 11} – 10{sup 13} W cm{sup -2}. (interaction of laser radiation with matter)« less

Green synthesis of silica nanoparticles using sugarcane bagasse

NASA Astrophysics Data System (ADS)

Mohd, Nur Kamilah; Wee, Nik Nur Atiqah Nik; Azmi, Alyza A.

2017-09-01

Silica nanoparticles have been great attention as it being evaluated for used in abundant fields and applications. Due to this significance, this research was conducted to synthesis silica nanoparticles using local agricultural waste, sugarcane bagasse. We executed extraction and precipitation process as it involved low cost, less toxic and low energy process compared to other methods. The Infrared (IR) spectra showed the vibration peak of Si-O-Si, which clearly be the evidence for the silica characteristics in the sample. In this research, amorphous silica nanoparticles with spherical morphology with an average size of 30 nm, and specific surface area of 111 m2/g-1 have been successfully synthesized. The XRD patterns showed the amorphous nature of silica nanoparticles. As a comparison, the produced silica nanoparticles from sugarcane bagasse are compared with the respective nanoparticles synthesized using Stöber method.

Direct and rapid determination of cotton maturity by FT-Mid-IR technique

USDA-ARS?s Scientific Manuscript database

FT-mid-IR (FT-MIR) spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-90...

Antibacterial Activity of Polyaniline Coated Silver Nanoparticles Synthesized from Piper Betle Leaves Extract.

PubMed

Mamun Or Rashida, Md; Shafiul Islam, Md; Azizul Haque, Md; Arifur Rahman, Md; Tanvir Hossain, Md; Abdul Hamid, Md

2016-01-01

Plants or natural resources have been found to be a good alternative method for nanoparticles synthesis. In this study, polyaniline coated silver nanoparticles (AgNPs) synthesized from Piper betle leaves extract were investigated for their antibacterial activity. Silver nanoparticles were prepared from the reduction of silver nitrate and NaBH4 was used as reducing agent. Silver nanoparticles and extracts were mixed thoroughly and then coated by polyaniline. Prepared nanoparticles were characterized by Visual inspection, Ultraviolet-visible spectroscopy (UV), Fourier transform infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) techniques. Antibacterial activities of the synthesized silver nanoparticles were tested against Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 14028, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. UV-Vis spectrum of reaction mixture showed strong absorption peak with centering at 400 nm. The FT-IR results imply that Ag-NPs were successfully synthesized and capped with bio-compounds present in P. betle. TEM image showed that Ag-NPs formed were well dispersed with a spherical structures and particle size ranging from 10 to 30 nm. The result revealed that Ag-Extract NPs showed 32.78±0.64 mm zone of inhibition against S. aureus, whereas norfloxacin (positive control) showed maximum 32.15±0.40 mm zone of inhibition for S. aureus. Again, maximum zone of inhibition 29.55±0.45 mm was found for S. typhi, 27.12±0.38 mm for E. coli and 21.95±0.45 mm for P. aeruginosa. The results obtained by this study can't be directly extrapolated to human; so further studies should be undertaken to established the strong antimicrobial activity of Ag-Extract NPs for drug development program.

Antibacterial Activity of Polyaniline Coated Silver Nanoparticles Synthesized from Piper Betle Leaves Extract

PubMed Central

Mamun Or Rashida, Md.; Shafiul Islam, Md.; Azizul Haque, Md.; Arifur Rahman, Md.; Tanvir Hossain, Md.; Abdul Hamid, Md.

2016-01-01

Plants or natural resources have been found to be a good alternative method for nanoparticles synthesis. In this study, polyaniline coated silver nanoparticles (AgNPs) synthesized from Piper betle leaves extract were investigated for their antibacterial activity. Silver nanoparticles were prepared from the reduction of silver nitrate and NaBH4 was used as reducing agent. Silver nanoparticles and extracts were mixed thoroughly and then coated by polyaniline. Prepared nanoparticles were characterized by Visual inspection, Ultraviolet-visible spectroscopy (UV), Fourier transform infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) techniques. Antibacterial activities of the synthesized silver nanoparticles were tested against Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 14028, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. UV–Vis spectrum of reaction mixture showed strong absorption peak with centering at 400 nm. The FT-IR results imply that Ag-NPs were successfully synthesized and capped with bio-compounds present in P. betle. TEM image showed that Ag-NPs formed were well dispersed with a spherical structures and particle size ranging from 10 to 30 nm. The result revealed that Ag-Extract NPs showed 32.78±0.64 mm zone of inhibition against S. aureus, whereas norfloxacin (positive control) showed maximum 32.15±0.40 mm zone of inhibition for S. aureus. Again, maximum zone of inhibition 29.55±0.45 mm was found for S. typhi, 27.12±0.38 mm for E. coli and 21.95±0.45 mm for P. aeruginosa. The results obtained by this study can’t be directly extrapolated to human; so further studies should be undertaken to established the strong antimicrobial activity of Ag-Extract NPs for drug development program. PMID:27642330

Spectroscopic studies of ozone in cryosolutions: FT-IR spectra of 16O3 in liquid nitrogen, oxygen, argon and krypton.

PubMed

Bulanin, Kirill M; Bulanin, Michael O; Rudakova, Aida V; Kolomijtsova, Tatiana D; Shchepkin, Dmitrij N

2018-03-15

We have measured and interpreted the IR spectra of ozone dissolved in liquid nitrogen, oxygen, argon, and krypton in the 650-4700cm -1 spectral region at 79-117K. Frequency shifts, band intensities and bandshapes of 22 spectral features of soluted ozone were analyzed. The bands of the А 1 symmetry have a complex contour and possess an excess intensity with respect to the value of the purely vibrational transition moment. It was found that this effect is related to the manifestation of the Coriolis interaction. The bandshape distortion manifests itself as an additional intensity from the side of the В 1 symmetry band being an intensity source in the case of the Coriolis interaction. Copyright © 2017. Published by Elsevier B.V.

Toward optimal spatial and spectral quality in widefield infrared spectromicroscopy of IR labelled single cells.

PubMed

Mattson, Eric C; Unger, Miriam; Clède, Sylvain; Lambert, François; Policar, Clotilde; Imtiaz, Asher; D'Souza, Roshan; Hirschmugl, Carol J

2013-10-07

Advancements in widefield infrared spectromicroscopy have recently been demonstrated following the commissioning of IRENI (InfraRed ENvironmental Imaging), a Fourier Transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center. The present study demonstrates the effects of magnification, spatial oversampling, spectral pre-processing and deconvolution, focusing on the intracellular detection and distribution of an exogenous metal tris-carbonyl derivative 1 in a single MDA-MB-231 breast cancer cell. We demonstrate here that spatial oversampling for synchrotron-based infrared imaging is critical to obtain accurate diffraction-limited images at all wavelengths simultaneously. Resolution criteria and results from raw and deconvoluted images for two Schwarzschild objectives (36×, NA 0.5 and 74×, NA 0.65) are compared to each other and to prior reports for raster-scanned, confocal microscopes. The resolution of the imaging data can be improved by deconvolving the instrumental broadening that is determined with the measured PSFs, which is implemented with GPU programming architecture for fast hyperspectral processing. High definition, rapidly acquired, FTIR chemical images of respective spectral signatures of the cell 1 and shows that 1 is localized next to the phosphate- and Amide-rich regions, in agreement with previous infrared and luminescence studies. The infrared image contrast, localization and definition are improved after applying proven spectral pre-processing (principal component analysis based noise reduction and RMie scattering correction algorithms) to individual pixel spectra in the hyperspectral cube.

a UV Spectral Library of Metal-Poor Massive Stars

NASA Astrophysics Data System (ADS)

Robert, Carmelle

1994-01-01

We propose to use the FOS to build a snapshot library of UV spectra of a sample of about 50 metal-poor massive stars located in the Magellanic Clouds. The majority of libraries already existing contains spectra of hot stars with chemical abundances close to solar. The high spectral resolution achieves with the FOS will be a major factor for the uniqueness of this new library. UV spectral libraries represent fundamental tools for the study of the massive star populations of young star-forming regions. Massive stars, which are impossible to identify directly in the optical-IR part of a composite spectrum, display on the other hand key signatures in the UV region. These signatures are mainly broad, metallicity dependent spectral features formed in the hot star winds. They require a high spectral resolution (of the order of 200-300 km/s) for an adequate study. A spectral library of metal-poor massive stars represents also a unique source of data for a stellar atmosphere analysis. Within less then 10 min we will obtain a high signal-to-noise ratio of at least 30. Finally, since short exposure times are possible, this proposal makes extremely good use of the capabilities of HST. We designed an observing strategy which yields a maximum scientific return at a minimum cost of spacecraft time.

Biosorption of food dyes onto Spirulina platensis nanoparticles: equilibrium isotherm and thermodynamic analysis.

PubMed

Dotto, G L; Lima, E C; Pinto, L A A

2012-01-01

The biosorption of food dyes FD&C red no. 40 and acid blue 9 onto Spirulina platensis nanoparticles was studied at different conditions of pH and temperature. Four isotherm models were used to evaluate the biosorption equilibrium and the thermodynamic parameters were estimated. Infra red analysis (FT-IR) and energy dispersive X-ray spectroscopy (EDS) were used to verify the biosorption behavior. The maximum biosorption capacities of FD&C red no. 40 and acid blue 9 were found at pH 4 and 298 K, and the values were 468.7 mg g(-1) and 1619.4 mg g(-1), respectively. The Sips model was more adequate to fit the equilibrium experimental data (R2>0.99 and ARE<5%). Thermodynamic study showed that the biosorption was exothermic, spontaneous and favorable. FT-IR and EDS analysis suggested that at pH 4 and 298 K, the biosorption of both dyes onto nanoparticles occurred by chemisorption. Copyright © 2011 Elsevier Ltd. All rights reserved.

Green synthesis of silver nanoparticles using marine algae Caulerpa racemosa and their antibacterial activity against some human pathogens

NASA Astrophysics Data System (ADS)

Kathiraven, T.; Sundaramanickam, A.; Shanmugam, N.; Balasubramanian, T.

2015-04-01

We present the synthesis and antibacterial activity of silver nanoparticles using Caulerpa racemosa, a marine algae. Fresh C. racemosa was collected from the Gulf of Mannar, Southeast coast of India. The seaweed extract was used for the synthesis of AgNO3 at room temperature. UV-visible spectrometry study revealed surface plasmon resonance at 413 nm. The characterization of silver nanoparticle was carried out using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscope (TEM). FT-IR measurements revealed the possible functional groups responsible for reduction and stabilization of the nanoparticles. X-ray diffraction analysis showed that the particles were crystalline in nature with face-centered cubic geometry.TEM micrograph has shown the formation of silver nanoparticles with the size in the range of 5-25 nm. The synthesized AgNPs have shown the best antibacterial activity against human pathogens such as Staphylococcus aureus and Proteus mirabilis. The above eco-friendly synthesis procedure of AgNPs could be easily scaled up in future for the industrial and therapeutic needs.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes.

PubMed

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy ( 1 H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1 H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes

PubMed Central

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

Ternary electrocatalysts for oxidizing ethanol to carbon dioxide: making ir capable of splitting C-C bond.

PubMed

Li, Meng; Cullen, David A; Sasaki, Kotaro; Marinkovic, Nebojsa S; More, Karren; Adzic, Radoslav R

2013-01-09

Splitting the C-C bond is the main obstacle to electrooxidation of ethanol (EOR) to CO(2). We recently demonstrated that the ternary PtRhSnO(2) electrocatalyst can accomplish that reaction at room temperature with Rh having a unique capability to split the C-C bond. In this article, we report the finding that Ir can be induced to split the C-C bond as a component of the ternary catalyst. We characterized and compared the properties of several carbon-supported nanoparticle (NP) electrocatalysts comprising a SnO(2) NP core decorated with multimetallic nanoislands (MM' = PtIr, PtRh, IrRh, PtIrRh) prepared using a seeded growth approach. An array of characterization techniques were employed to establish the composition and architecture of the synthesized MM'/SnO(2) NPs, while electrochemical and in situ infrared reflection absorption spectroscopy studies elucidated trends in activity and the nature of the reaction intermediates and products. Both EOR reactivity and selectivity toward CO(2) formation of several of these MM'/SnO(2)/C electrocatalysts are significantly higher compared to conventional Pt/C and Pt/SnO(2)/C catalysts. We demonstrate that the PtIr/SnO(2)/C catalyst with high Ir content shows outstanding catalytic properties with the most negative EOR onset potential and reasonably good selectivity toward ethanol complete oxidation to CO(2).

Wetlands delineation by spectral signature analysis and legal implications

NASA Technical Reports Server (NTRS)

Anderon, R. R.; Carter, V.

1972-01-01

High altitude analysis of wetland resources and the use of such information in an operational mode to address specific problems of wetland preservation at a state level are discussed. Work efforts were directed toward: (1) developing techniques for using large scale color IR photography in state wetlands mapping program, (2) developing methods for obtaining wetlands ecology information from high altitude photography, (3) developing means by which spectral data can be more accurately analyzed visually, and (4) developing spectral data for automatic mapping of wetlands.

New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies

NASA Astrophysics Data System (ADS)

Nallathamby, Prakash D.; Mortensen, Ninell P.; Palko, Heather A.; Malfatti, Mike; Smith, Catherine; Sonnett, James; Doktycz, Mitchel J.; Gu, Baohua; Roeder, Ryan K.; Wang, Wei; Retterer, Scott T.

2015-04-01

functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach described here is applicable to the synthesis of a large class of nanomaterials with multiple core and surface functionalities. This work combined with the biodistribution data suggests that the radiolabeling schemes carried out in this study have broad implications for use in pharmacokinetic studies for a variety of nanomaterials. Electronic supplementary information (ESI) available: (S1) High-Resolution Transmission Electron Microscopy (HRTEM) image of iron oxide nanoparticles, (S2) Superconducting Quantum Interference Device (SQUID) measurement of magnetization of super paramagnetic iron oxide nanoparticles, (S3) Fourier Transform Infrared Spectroscopy (FT-IR) spectra of Fe-Si-COO- synthesised using Grignard reagents (S4) FT-IR spectra of iron oxide nanoparticles silanized with commercially available N-[(3-Trimethoxysilyl)propyl]ethylenediamine triacetic acid tripotassium salt, (S5) Synthesis of hyperbranched amine functionalized iron oxide nanoparticles from amino propyl triethyl silane functionalized iron nanoparticles using ethyleneimine as an initiator and polymerizing agent. See DOI: 10.1039/c4nr06441k

H/D isotopic recognition and temperature effects in IR spectra of hydrogen-bonded cyclic dimers in crystals: 3-Methylcinnamic acid and 4-phenylbutyric acid

NASA Astrophysics Data System (ADS)

Hachuła, Barbara; Jabłońska-Czapla, Magdalena; Flakus, Henryk T.; Nowak, Maria; Kusz, Joachim

2015-01-01

In the present work, the experimental and theoretical study of the nature of the inter-hydrogen bond interactions in two different carboxylic acids, 3-methylcinnamic acid (3MCA) and 4-phenylbutyric acid (4PBA), were reported. The polarized IR spectra of 3MCA and 4PBA crystals were recorded at the frequency ranges of the νOsbnd H and νOsbnd D bands. The spectral properties of 3MCA and 4PBA interpreted with the aid of the calculations based on the "strong-coupling" model. The differences in the spectral properties of the two different dimeric systems in the crystals provide a valuable information about the existence of a direct relationship between the crystal spectral properties in IR and the electronic structure of the molecular systems. In 3MCA crystals strong vibrational exciton interactions favor a "tail-to-head" (TH)-type Davydov coupling widespread via the π-electrons, whereas in 4PBA crystals a weak "through-space" (SS) exciton coupling is responsible for a "side-to-side"-type coupling. The relative contribution of each individual exciton coupling mechanism in IR spectra generation strongly depends on temperature and molecular electronic structure. The H/D isotopic recognition effect, depending on a non-random distribution of protons and deuterons in the crystal hydrogen bridges, was also analyzed.

Spectral Invariance Principles Observed in Spectral Radiation Measurements of the Transition Zone

NASA Technical Reports Server (NTRS)

Marshak, Alexander

2011-01-01

The main theme for our research is the understanding and closure of the surface spectral shortwave radiation problem in fully 3D cloud situations by combining the new ARM scanning radars, shortwave spectrometers, and microwave radiometers with the arsenal of radiative transfer tools developed by our group. In particular, we define first a large number of cloudy test cases spanning all 3D possibilities not just the customary uniform-overcast ones. Second, for each case, we define a "Best Estimate of Clouds That Affect Shortwave Radiation" using all relevant ARM instruments, notably the new scanning radars, and contribute this to the ARM Archive. Third, we test the ASR-signature radiative transfer model RRTMG_SW for those cases, focusing on the near-IR because of long-standing problems in this spectral region, and work with the developers to improve RRTMG_SW in order to increase its penetration into the modeling community.

General review of multispectral cooled IR development at CEA-Leti, France

NASA Astrophysics Data System (ADS)

Boulard, F.; Marmonier, F.; Grangier, C.; Adelmini, L.; Gravrand, O.; Ballet, P.; Baudry, X.; Baylet, J.; Badano, G.; Espiau de Lamaestre, R.; Bisotto, S.

2017-02-01

Multicolor detection capabilities, which bring information on the thermal and chemical composition of the scene, are desirable for advanced infrared (IR) imaging systems. This communication reviews intra and multiband solutions developed at CEA-Leti, from dual-band molecular beam epitaxy grown Mercury Cadmium Telluride (MCT) photodiodes to plasmon-enhanced multicolor IR detectors and backside pixelated filters. Spectral responses, quantum efficiency and detector noise performances, pros and cons regarding global system are discussed in regards to technology maturity, pixel pitch reduction, and affordability. From MWIR-LWIR large band to intra MWIR or LWIR bands peaked detection, results underline the full possibility developed at CEA-Leti.

Unusual island formations of Ir on Ge (111) studied by STM

NASA Astrophysics Data System (ADS)

van Zijll, M.; Huffman, E.; Lovinger, D. J.; Chiang, S.

2017-12-01

Island formation on the Ir/Ge(111) surface is studied using ultrahigh vacuum scanning tunneling microscopy. Ir was deposited at room temperature onto a Ge (111) substrate with coverages between 0.5 and 2.0 monolayers (ML). The samples were annealed to temperatures between 550 and 800 K, and then cooled prior to imaging. With 1.0 ML Ir coverage, at annealing temperatures 650-750 K, round islands form at locations where domain boundaries of the substrate reconstruction intersect. Both the substrate and the islands display a (√{ 3} x√{ 3}) R30∘ reconstruction. Additionally, a novel surface formation is observed where the Ir gathers along the antiphase domain boundaries between competing surface domains of the Ge surface reconstruction. This gives the appearance of the Ir in the domain boundaries forming pathways between different islands. The islands formed at higher annealing temperatures resulted in larger island sizes, which is evidence of Ostwald ripening. We present a model for the islands and the pathways which is consistent with our observations.

Fabrication of IrSi(3)/p-Si Schottky diodes by a molecular beam epitaxy technique

NASA Technical Reports Server (NTRS)

Lin, T. L.; Iannelli, J. M.

1990-01-01

IrSi(3)/p-Si Schottky diodes have been fabricated by a molecular beam epitaxy technique at 630 C. Good surface morphology was observed for IrSi(3) layers grown at temperatures below 680 C, and an increasing tendency to form islands is observed in samples grown at higher temperatures. Good diode current-voltage characteristics were observed and Schottky barrier heights of 0.14-0.18 eV were determined by activation energy analysis and spectral response measurement.

Thermal, structural, functional, optical and magnetic studies of pure and Ba doped CdO nanoparticles.

PubMed

Sivakumar, S; Venkatesan, A; Soundhirarajan, P; Khatiwada, Chandra Prasad

2015-12-05

In this research, a chemical precipitation method was used to synthesize undoped and doped cadmium oxide nanoparticles and studied by TG-DTA, XRD, FT-IR, SEM, with EDX and antibacterial activities, respectively. The melting points, thermal stability and the kinetic parameters like entropy (ΔS), enthalpy (ΔH), Gibb's energy (ΔG), activation energy (E), frequency factor (A) were evaluated from TG-DTA measurements. X-ray diffraction analysis (XRD) brought out the information about the synthesized products exist in spherical in shape with cubic structure. The functional groups and band area of the samples were established by Fourier transform infrared (FT-IR) spectroscopy. The direct and indirect band gap energy of pure and doped samples were determined by UV-Vis-DRS. The surface morphological, elemental compositions and particles sizes were evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Finally, antibacterial activities indicated the Gram-positive and Gram-negative bacteria are more active in transporter, dehydrogenize and periplasmic enzymatic activities of pure and doped samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Automated ablation of dental composite using an IR pulsed laser coupled to a plume emission spectral feedback system.

PubMed

Jang, Andrew T; Chan, Kenneth H; Fried, Daniel

2017-09-01

The purpose of this study is to assemble a laser system for the selective removal of dental composite from tooth surfaces, that is feasible for clinical use incorporating a spectral feedback system, a scanning system, articulating arm and a clinical hand-piece, and evaluate the performance of that system on extracted teeth. Ten extracted teeth were collected and small fillings were placed on the occlusal surface of each tooth. A clinical system featuring a CO 2 laser operating at 50 Hz and spectral optical feedback was used to remove the composite. Removal was confirmed using a cross polarized optical coherence tomography (CP-OCT) system designed for clinical use. The system was capable of rapidly removing composite from small preparations on tooth occlusal surfaces with a mean loss of enamel of less than 20 μm. We have demonstrated that spectral feedback can be successfully employed in an automated system for composite removal by incorporating dual photodiodes and a galvanometer controlled CO 2 laser. Additionally, the use of registered OCT images presents as a viable method for volumetric benchmarking. Overall, this study represents the first implementation of spectral feedback into a clinical hand-piece and serves as a benchmark for a future clinical study. Lasers Surg. Med. 49:658-665, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert M. Malone, Ian J. McKenna

2008-03-01

A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light Source at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolicmore » mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement single-point pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.« less

Photosensitized synthesis of silver nanoparticles using Withania somnifera leaf powder and silver nitrate.

PubMed

Raut, Rajesh Warluji; Mendhulkar, Vijay Damodhar; Kashid, Sahebrao Balaso

2014-03-05

The metal nanoparticle synthesis is highly explored field of nanotechnology. The biological methods seem to be more effective; however, due to slow reduction rate and polydispersity of the resulting products, they are less preferred. In the present study, we report rapid and facile synthesis of silver nanoparticles at room temperature. The exposure of reaction mixtures containing silver nitrate and dried leaf powder of Withania somnifera Linn to direct sunlight resulted in reduction of metal ions within five minutes whereas, the dark exposure took almost 12h. Further studies using different light filters reveal the role of blue light in reduction of silver ions. The synthesized silver nanoparticles were characterized by UV-Vis, Infrared spectroscopy (IR), Transmission Electron Microscopy (TEM), X-ray Diffraction studies (XRD), Nanoparticle Tracking Analysis (NTA), Energy Dispersive Spectroscopy (EDS), and Cyclic Voltammetry (CV). The Antibacterial and antifungal studies showed significant activity as compared to their respective standards. Copyright © 2014 Elsevier B.V. All rights reserved.

Vibrational and theoretical study of selected diacetylenes.

PubMed

Roman, Maciej; Baranska, Malgorzata

2013-11-01

Six commonly used disubstituted diacetylenes with short side-chains (RCCCCR, where R=CH2OH, CH2OPh, C(CH3)2OH, C(CH3)3, Si(CH3)3, and Ph) were analyzed using vibrational spectroscopy and quantum-chemical calculations to shed new light on structural and spectroscopic properties of these compounds. Prior to that the conformational analysis of diacetylenes was performed to search the Potential Energy Surface for low-energy minima. Theoretical investigations were followed by the potential energy distribution (PED) analysis to gain deeper insight into FT-Raman and FT-IR spectra that, in some cases, were recorded for the first time for the studied compounds. The analysis was focused mainly on spectral features of the diacetylene system sensitive to the substitution. Shifts of the characteristic bands and changes in bond lengths were observed when changing the substituent. Furthermore, Fermi resonance was observed in the vibrational spectra of some diacetylenes. FT-IR spectra were measured by using two methods, i.e. transmission (with KBr substrate) and Attenuated Total Reflection (ATR), showing the latter adequate and fast tool for IR measurements of diacetylenes. Additionally, Surface Enhanced Raman Spectroscopy (SERS) was applied for phenyl derivative for the first time to study its interaction with metallic nanoparticles that seems to be perpendicular. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of a spectral break in the nonthermal emission of AO 0235+164

NASA Technical Reports Server (NTRS)

Odell, S. L.; Puschell, J. J.; Stein, W. A.; Warner, J. W.

1977-01-01

Results are reported for braod-band photometry of the BL Lac object AO 0235+164 carried out over the spectral range from 0.36 to 3.5 microns in December 1975 and in October and November 1976. It is found that the continuum of this object steepened at visible wavelengths between December 1975 and October 1976, but maintained a relatively constant slope in the near-IR despite a factor-of-ten decrease in flux from the maximum level. Visible-wavelength data are cited which appear to suggest that the steepening of the visible spectrum occurred in less than 300 days, while the near-IR level may have been nearly constant. It is shown that the observed change in the spectral shape of the visible-wavelength continuum cannot be explained in terms of a 'composite' model consisting of an unchanging galaxy and a varying nonthermal source with constant spectral index. Two other general classes of models are considered: intrinsic variability and extrinsic modulation.

Biosynthesis of silver nanoparticles using Alternanthera sessilis (Linn.) extract and their antimicrobial, antioxidant activities.

PubMed

Niraimathi, K L; Sudha, V; Lavanya, R; Brindha, P

2013-02-01

The present work focuses the use of the aqueous extract of Alternanthera sessilis Linn. (Amaranthaceae) in producing silver nanoparticles (AgNPs) from silver nitrate aqueous. Phytochemical analysis of the extract revealed the presence of alkaloid, tannins, ascorbic acid, carbohydrates and proteins and they serve as effective reducing and capping agents for converting silver nitrate into nanoparticles. The synthesized silver nanoparticles (AgNPs) were also tested for proteins and ascorbic acid. Its pH was also determined (5.63). The AgNPs obtained was characterized by UV-vis spectroscopy, FT-IR spectroscopy, SEM, Zeta sizer and TG-DSC. SEM images which revealed the presence of various shapes and sizes. FT-IR spectrum showed the AgNPs having a coating of proteins indicating a dual role of bio-molecules responsible for capping and efficient stabilization of the silver nanoparticles. Presence of impurities and melting point profile were screened by TG-DSC analyzer. AgNPs were synthesized from the silver nitrate through the reducing power of ascorbic acid present in A. sessilis leaves. In this study, we also investigated antimicrobial and antioxidant activity of green synthesized AgNPs. The antimicrobial activity is investigated by Bauer et al.'s method. Antioxidant activity was done by DPPH method. Copyright © 2012 Elsevier B.V. All rights reserved.

In vivo small animal micro-CT using nanoparticle contrast agents

PubMed Central

Ashton, Jeffrey R.; West, Jennifer L.; Badea, Cristian T.

2015-01-01

Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research. PMID:26581654

Development of silane grafted ZnO core shell nanoparticles loaded diglycidyl epoxy nanocomposites film for antimicrobial applications.

PubMed

Suresh, S; Saravanan, P; Jayamoorthy, K; Ananda Kumar, S; Karthikeyan, S

2016-07-01

In this article a series of epoxy nanocomposites film were developed using amine functionalized (ZnO-APTES) core shell nanoparticles as the dispersed phase and a commercially available epoxy resin as the matrix phase. The functional group of the samples was characterized using FT-IR spectra. The most prominent peaks of epoxy resin were found in bare epoxy and in all the functionalized ZnO dispersed epoxy nanocomposites (ZnO-APTES-DGEBA). The XRD analysis of all the samples exhibits considerable shift in 2θ, intensity and d-spacing values but the best and optimum concentration is found to be 3% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposites supported by FT-IR results. From TGA measurements, 100wt% residue is obtained in bare ZnO nanoparticles whereas in ZnO core shell nanoparticles grafted DGEBA residue percentages are 37, 41, 45, 46 and 52% for 0, 1, 3, 5 and 7% ZnO-APTES-DGEBA respectively, which is confirmed with ICP-OES analysis. From antimicrobial activity test, it was notable that antimicrobial activity of 7% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposite film has best inhibition zone effect against all pathogens under study. Copyright © 2016 Elsevier B.V. All rights reserved.

Modular Spectral Inference Framework Applied to Young Stars and Brown Dwarfs

NASA Technical Reports Server (NTRS)

Gully-Santiago, Michael A.; Marley, Mark S.

2017-01-01

In practice, synthetic spectral models are imperfect, causing inaccurate estimates of stellar parameters. Using forward modeling and statistical inference, we derive accurate stellar parameters for a given observed spectrum by emulating a grid of precomputed spectra to track uncertainties. Spectral inference as applied to brown dwarfs re: Synthetic spectral models (Marley et al 1996 and 2014) via the newest grid spans a massive multi-dimensional grid applied to IGRINS spectra, improving atmospheric models for JWST. When applied to young stars(10Myr) with large starpots, they can be measured spectroscopically, especially in the near-IR with IGRINS.

Diamond-like nanoparticles influence on flavonoids transport: molecular modelling

NASA Astrophysics Data System (ADS)

Plastun, Inna L.; Agandeeva, Ksenia E.; Bokarev, Andrey N.; Zenkin, Nikita S.

2017-03-01

Intermolecular interaction of diamond-like nanoparticles and flavonoids is investigated by numerical simulation. Using molecular modelling by the density functional theory method, we analyze hydrogen bonds formation and their influence on IR - spectra and structure of molecular complex which is formed due to interaction between flavonoids and nanodiamonds surrounded with carboxylic groups. Enriched adamantane (1,3,5,7 - adamantanetetracarboxylic acid) is used as an example of diamond-like nanoparticles. Intermolecular forces and structure of hydrogen bonds are investigated. IR - spectra and structure parameters of quercetin - adamantanetetracarboxylic acid molecular complex are obtained by numerical simulation using the Gaussian software complex. Received data coincide well with experimental results. Intermolecular interactions and hydrogen bonding structure in the obtained molecular complex are examined. Possibilities of flavonoids interaction with DNA at the molecular level are also considered.

Electronic structure, local magnetism, and spin-orbit effects of Ir(IV)-, Ir(V)-, and Ir(VI)-based compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laguna-Marco, M. A.; Kayser, P.; Alonso, J. A.

2015-06-01

Element- and orbital-selective x-ray absorption and magnetic circular dichroism measurements are carried out to probe the electronic structure and magnetism of Ir 5d electronic states in double perovskite Sr2MIrO6 (M = Mg, Ca, Sc, Ti, Ni, Fe, Zn, In) and La2NiIrO6 compounds. All the studied systems present a significant influence of spin-orbit interactions in the electronic ground state. In addition, we find that the Ir 5d local magnetic moment shows different character depending on the oxidation state despite the net magnetization being similar for all the compounds. Ir carries an orbital contribution comparable to the spin contribution for Ir4+ (5d(5))more » and Ir5+ (5d(4)) oxides, whereas the orbital contribution is quenched for Ir6+ (5d(3)) samples. Incorporation of a magnetic 3d atom allows getting insight into the magnetic coupling between 5d and 3d transition metals. Together with previous susceptibility and neutron diffractionmeasurements, the results indicate that Ir carries a significant local magnetic moment even in samples without a 3d metal. The size of the (small) net magnetization of these compounds is a result of predominant antiferromagnetic interactions between local moments coupled with structural details of each perovskite structure« less

Synthesis and properties of silver nanoparticles in sodium bismuth borate glasses

NASA Astrophysics Data System (ADS)

Patwari, D. Rajeshree; Eraiah, B.

2018-04-01

Rare earth doped Sodium Bismuth Borate glass samples with silver chloride were prepared by melt quenching method. X-Ray diffraction pattern was used to confirm the amorphous nature of the samples. UV-Visible Spectra was recorded to study the optical properties. Surface plasmon resonance (SPR) peak was observed due to the formation of silver nanoparticles before and after heat treatment and the presence of silver nanoparticles were confirmed by UV-Visible Spectral studies and transmission electron microscopy. The surface plasmon resonance band became wider and red shifted after longer heat treatment.

Modified ferrite core-shell nanoparticles magneto-structural characterization

NASA Astrophysics Data System (ADS)

Klekotka, Urszula; Piotrowska, Beata; Satuła, Dariusz; Kalska-Szostko, Beata

2018-06-01

In this study, ferrite nanoparticles with core-shell structures and different chemical compositions of both the core and shell were prepared with success. Proposed nanoparticles have in the first and second series magnetite core, and the shell is composed of a mixture of ferrites with Fe3+, Fe2+ and M ions (where M = Co2+, Mn2+ or Ni2+) with a general composition of M0.5Fe2.5O4. In the third series, the composition is inverted, the core is composed of a mixture of ferrites and as a shell magnetite is placed. Morphology and structural characterization of nanoparticles were done using Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and Infrared spectroscopy (IR). While room temperature magnetic properties were measured using Mössbauer spectroscopy (MS). It is seen from Mössbauer measurements that Co always increases hyperfine magnetic field on Fe atoms at RT, while Ni and Mn have opposite influences in comparison to pure Fe ferrite, regardless of the nanoparticles structure.

Missing Fe: hydrogenated iron nanoparticles

NASA Astrophysics Data System (ADS)

Bilalbegović, G.; Maksimović, A.; Mohaček-Grošev, V.

2017-03-01

Although it was found that the FeH lines exist in the spectra of some stars, none of the spectral features in the interstellar medium (ISM) have been assigned to this molecule. We suggest that iron atoms interact with hydrogen and produce Fe-H nanoparticles which sometimes contain many H atoms. We calculate infrared spectra of hydrogenated iron nanoparticles using density functional theory methods and find broad, overlapping bands. Desorption of H2 could induce spinning of these small Fe-H dust grains. Some of hydrogenated iron nanoparticles possess magnetic and electric moments and should interact with electromagnetic fields in the ISM. FenHm nanoparticles could contribute to the polarization of the ISM and the anomalous microwave emission. We discuss the conditions required to form FeH and FenHm in the ISM.

Green synthesis of silver nanoparticles using Alternanthera dentata leaf extract at room temperature and their antimicrobial activity

NASA Astrophysics Data System (ADS)

Kumar, Deenadayalan Ashok; Palanichamy, V.; Roopan, Selvaraj Mohana

2014-06-01

A green rapid biogenic synthesis of silver nanoparticles AgNPs using Alternanthera dentata (A. dentata) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 430 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by A. dentata extract was completed within 10 min. Synthesized nanoparticles were characterized using UV-visible spectroscopy; Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM). The extracellular silver nanoparticles synthesis by aqueous leaf extract demonstrates rapid, simple and inexpensive method comparable to chemical and microbial methods. The colloidal solution of silver nanoparticles were found to exhibit antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and, Enterococcus faecalis.

The toxic effects of l-Cysteine-capped cadmium sulfide nanoparticles on the aquatic plant Spirodela polyrrhiza

NASA Astrophysics Data System (ADS)

Khataee, Alireza; Movafeghi, Ali; Nazari, Fatemeh; Vafaei, Fatemeh; Dadpour, Mohammad Reza; Hanifehpour, Younes; Joo, Sang Woo

2014-12-01

Plants play an important role in the fate of nanoparticles in the environment through their uptake, bioaccumulation, and transfer to trophic chains. However, the impacts of nanoparticles on plants as essential components of all ecosystems are not well documented. In the present study, the toxic effects of l-Cysteine-capped CdS nanoparticles on Spirodela polyrrhiza as an aquatic higher plant species were studied. l-Cysteine-capped CdS nanoparticles were synthesized using hydrothermal method and their characteristics were determined by XRD, SEM, HR-TEM, and FT-IR techniques. The diameter of majority of synthesized nanoparticles was about 15-20 nm. Subsequently, the uptake of l-Cysteine-capped CdS nanoparticles by the plant species was confirmed using epifluorescence microscopy. The activity of peroxidase and superoxide dismutase as antioxidant enzymes was assayed and the relative frond number was calculated in the presence of different concentrations of l-Cysteine-capped CdS nanoparticles. The obtained results revealed the toxic effects of the synthesized nanoparticles on S. polyrrhiza, leading to growth reduction and significant changes in antioxidant enzymes' activity.

Growth and spectral-luminescent study of SrMoO4 crystals doped with Tm3+ ions

NASA Astrophysics Data System (ADS)

Dunaeva, E. E.; Zverev, P. G.; Doroshenko, M. E.; Nekhoroshikh, A. V.; Ivleva, L. I.; Osiko, V. V.

2016-03-01

SrMoO4 crystals doped with Tm3+ ions have been produced from a melt using the Czochralski method; their spectral-luminescent characteristics have been studied, and laser radiation has been generated at the wavelength of 1.94 μm using laser-diode excitation. The high absorption section at the wavelength of 795 nm, the fairly high luminescence section, the long lifetime at the upper laser level 3F4 of 1.5 ms, and a wide luminescence band allow one to hope for developing efficient tunable Tm3+: SrMoO4 crystal lasers with diode pumping in the range of 1.7-2.0 μm, which are capable of implementing SRS self-transformation of radiation into the middle IR band.

Synthesis and Spectral Evaluation of Some Unsymmetrical Mesoporphyrinic Complexes

PubMed Central

Boscencu, Rica; Oliveira, Anabela Sousa; Ferreira, Diana P.; Ferreira, Luís Filipe Vieira

2012-01-01

Synthesis and spectral evaluation of new zinc and copper unsymmetrical mesoporphyrinic complexes are reported. Zn(II)-5-(4-acetoxy-3-methoxyphenyl)-10,15,20- tris-(4-carboxymethylphenyl)porphyrin, Zn(II)-5-[(3,4-methylenedioxy)phenyl]-10,15,20- tris-(4-carboxymethylphenyl)porphyrin, Cu(II)-5-(4-acetoxy-3-methoxyphenyl)-10,15,20- tris-(4-carboxymethylphenyl)porphyrin and Cu(II)-5-[(3,4-methylenedioxy)phenyl]-10,15,20- tris-(4-carboxymethylphenyl)porphyrin were synthesized using microwave-assisted synthesis. The complexes were characterized by elemental analysis, FT-IR, UV-Vis, EPR and NMR spectroscopy, which fully confirmed their structure. The spectral absorption properties of the porphyrinic complexes were studied in solvents with different polarities. Fluorescence emission and singlet oxygen formation quantum yields were evaluated for the compounds under study, revealing high yields for the zinc derivatives. The copper complexes are not emissive and only display residual capacity for singlet oxygen formation. PMID:22942693

Assessing soybean leaf area and leaf biomass by spectral measurements

NASA Technical Reports Server (NTRS)

Holben, B. N.; Tucker, C. J.; Fan, C. J.

1979-01-01

Red and photographic infrared spectral radiances were correlated with soybean total leaf area index, green leaf area index, chlorotic leaf area index, green leaf biomass, chlorotic leaf biomass, and total biomass. The most significant correlations were found to exist between the IR/red radiance ratio data and green leaf area index and/or green leaf biomass (r squared equals 0.85 and 0.86, respectively). These findings demonstrate that remote sensing data can supply information basic to soybean canopy growth, development, and status by nondestructive determination of the green leaf area or green leaf biomass.

Probing Radiation Pressure and Hot Gas Feedback through Spectral Simulation of Mid-IR to Submillimeter Fine-Structure Lines in Ultraluminous Infrared Galaxies

NASA Astrophysics Data System (ADS)

Fischer, Jacqueline

observations from Spitzer IRS, Herschel PACS, and Herschel SPIRE that heretofore have never been analyzed together in a comprehensive fashion. The publically available Cloudy spectral synthesis code includes photoionization physics, as well as the physics of the transition regions between HII regions and molecular clouds (photodissociation regions (PDRs) and X-ray dominated regions (XDRs) existing beyond the hot ionized centers of AGNs and the cold conditions in molecular clouds. In previous work using Cloudy, we modeled the far-infrared spectra in a sample of the 10 brightest galaxies at 60 microns with infrared luminosities greater than 10^10 Lsol. We showed that both high ionization parameters and high far-infrared optical depths are necessary to explain the far-infrared line deficits found in the only ULIRG in that sample. Here we propose to further develop these models and to apply them for the first time to the full set of available mid-IR, far-IR, and submillimeter spectroscopic observations of 20 ULIRGs and a small comparison sample of LIRGs in the Spitzer and Herschel Archives with multilevel OH observations. With the constraints provided by the numerous mid-IR through submillimeter fine-structure line diagnostics for each galaxy we will evaluate the relative dynamical importance of radiation pressure and hot gas pressure during this pivotal stage of galaxy evolution, and will determine which of these mechanisms is responsible for the momentum fluxes we derived from the multilevel OH Herschel observations of galaxies with powerful molecular outflows.

Development of detailed design concepts for the EarthCARE multi-spectral imager

NASA Astrophysics Data System (ADS)

Lobb, Dan; Escadero, Isabel; Chang, Mark; Gode, Sophie

2017-11-01

The EarthCARE mission is dedicated to the study of clouds by observations from a satellite in low Earth orbit. The payload will include major radar and LIDAR instruments, supported by a multi-spectral imager (MSI) and a broadband radiometer. The paper describes development of detailed design concepts for the MSI, and analysis of critical performance parameters. The MSI will form Earth images at 500m ground sample distance (GSD) over a swath width of 150km, from a nominal platform altitude of around 400km. The task of the MSI is to provide spatial context for the single-point measurements made by the radar and LIDAR systems; it will image Earth in 7 spectral bands: one visible, one near-IR, two short-wave IR and three thermal IR. The MSI instrument will be formed in two parts: a visible-NIR-SWIR (VNS) system, radiometrically calibrated using a sunilluminated diffuser, and a thermal IR (TIR) system calibrated using cold space and an internal black-body. The VNS system will perform push-broom imaging, using linear array detectors (silicon and InGaAs) and 4 separate lenses. The TIR system will use a microbolometer array detector in a time delay and integration (TDI) mode. Critical issues discussed for the VNS system include detector selection and detailed optical design trade-offs. The latter are related to the desirability of dichroics to achieve a common aperture, which influences the calibration hardware and lens design. The TIR system's most significant problems relate to control of random noise and bias errors, requiring optimisation of detector operation and calibration procedures.

Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

PubMed

Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

2015-03-03

Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data.

High-speed spectral infrared imaging of spark ignition engine combustion. (Reannouncement with new availability information)

DOE Office of Scientific and Technical Information (OSTI.GOV)

McComiskey, T.; Jiang, H.; Qian, Y.