Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques

NASA Astrophysics Data System (ADS)

Du, Yong; Fang, Hong Xia; Zhang, Qi; Zhang, Hui Li; Hong, Zhi

2016-01-01

As an important component of double-stranded DNA, adenine has powerful hydrogen-bond capability, due to rich hydrogen bond donors and acceptors existing within its molecular structure. Therefore, it is easy to form cocrystal between adenine and other small molecules with intermolecular hydrogen-bond effect. In this work, cocrystal of adenine and fumaric acid has been characterized as model system by FT-IR and FT-Raman spectral techniques. The experimental results show that the cocrystal formed between adenine and fumaric acid possesses unique spectroscopical characteristic compared with that of starting materials. Density functional theory (DFT) calculation has been performed to optimize the molecular structures and simulate vibrational modes of adenine, fumaric acid and the corresponding cocrystal. Combining the theoretical and experimental vibrational results, the characteristic bands corresponding to bending and stretching vibrations of amino and carbonyl groups within cocrystal are shifted into lower frequencies upon cocrystal formation, and the corresponding bond lengths show some increase due to the effect of intermolecular hydrogen bonding. Different vibrational modes shown in the experimental spectra have been assigned based on the simulation DFT results. The study could provide experimental and theoretical benchmarks to characterize cocrystal formed between active ingredients and cocrystal formers and also the intermolecular hydrogen-bond effect within cocrystal formation process by vibrational spectroscopic techniques.

Chromatography in the detection and characterization of illegal pharmaceutical preparations.

PubMed

Deconinck, Eric; Sacré, Pierre-Yves; Courselle, Patricia; De Beer, Jacques O

2013-09-01

Counterfeit and illegal pharmaceutical products are an increasing worldwide problem and constitute a major challenge for analytical laboratories to detect and characterize them. Spectroscopic techniques such as infrared spectroscopy and Raman spectroscopy have always been the first methods of choice to detect counterfeits and illegal preparations, but due to the evolution in the seized products and the necessity of risk assessment, chromatographic methods are becoming more important in this domain. This review intends to give a general overview of the techniques described in literature to characterize counterfeit and illegal pharmaceutical preparations, focusing on the role of chromatographic techniques with different detection tools.

Chemical Fingerprinting of Materials Developed Due To Environmental Issues

NASA Technical Reports Server (NTRS)

Smith, Doris A.; McCool, A. (Technical Monitor)

2000-01-01

This paper presents viewgraphs on chemical fingerprinting of materials developed due to environmental issues. Some of the topics include: 1) Aerospace Materials; 2) Building Blocks of Capabilities; 3) Spectroscopic Techniques; 4) Chromatographic Techniques; 5) Factors that Determine Fingerprinting Approach; and 6) Fingerprinting: Combination of instrumental analysis methods that diagnostically characterize a material.

Triterpene derivatives from Abies spectabilis leaves of Nepalese origin.

PubMed

Dall'Acqua, Stefano; Minesso, Paola; Comai, Stefano; Shrestha, Bharat Babu; Gewali, Mohan Bikram; Jha, Pramod Kumar; Innocenti, Gabbriella

2011-06-01

Our ongoing studies of Nepalese medicinal plants has led to the isolation and characterization of five new triterpenes, two known triterpenes and two phenolic derivatives from Abies spectabilis (D.Don) Mirb leaves grown in the high mountain. The structures of the isolated compounds were characterized by means of 1D and 2D NMR spectroscopic and MS techniques.

Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques.

PubMed

Du, Yong; Fang, Hong Xia; Zhang, Qi; Zhang, Hui Li; Hong, Zhi

2016-01-15

As an important component of double-stranded DNA, adenine has powerful hydrogen-bond capability, due to rich hydrogen bond donors and acceptors existing within its molecular structure. Therefore, it is easy to form cocrystal between adenine and other small molecules with intermolecular hydrogen-bond effect. In this work, cocrystal of adenine and fumaric acid has been characterized as model system by FT-IR and FT-Raman spectral techniques. The experimental results show that the cocrystal formed between adenine and fumaric acid possesses unique spectroscopical characteristic compared with that of starting materials. Density functional theory (DFT) calculation has been performed to optimize the molecular structures and simulate vibrational modes of adenine, fumaric acid and the corresponding cocrystal. Combining the theoretical and experimental vibrational results, the characteristic bands corresponding to bending and stretching vibrations of amino and carbonyl groups within cocrystal are shifted into lower frequencies upon cocrystal formation, and the corresponding bond lengths show some increase due to the effect of intermolecular hydrogen bonding. Different vibrational modes shown in the experimental spectra have been assigned based on the simulation DFT results. The study could provide experimental and theoretical benchmarks to characterize cocrystal formed between active ingredients and cocrystal formers and also the intermolecular hydrogen-bond effect within cocrystal formation process by vibrational spectroscopic techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

NASA Astrophysics Data System (ADS)

Coanga, Jean-Maurice

2013-04-01

Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

Novel heterocyclic thiosemicarbazones derivatives as colorimetric and "turn on" fluorescent sensors for fluoride anion sensing employing hydrogen bonding.

PubMed

Ashok Kumar, S L; Saravana Kumar, M; Sreeja, P B; Sreekanth, A

2013-09-01

Two novel heterocyclic thiosemicarbazone derivatives have been synthesized, and characterized, by means of spectroscopic and single crystal X-ray diffraction methods. Their chromophoric-fluorogenic response towards anions in competing solvent dimethyl sulfoxide (DMSO) was studied. The receptor shows selective recognition towards fluoride anion. The binding affinity of the receptors with fluoride anion was calculated using UV-visible and fluorescence spectroscopic techniques. Copyright © 2013 Elsevier B.V. All rights reserved.

Study of spectroscopic properties of nanosized particles of core-shell morphology

NASA Astrophysics Data System (ADS)

Bzhalava, T. N.; Kervalishvili, P. J.

2018-03-01

Method of studying spectroscopic properties of nanosized particles and estimation of resonance wavelength range for determination of specific and unique “spectral” signatures in purpose of sensing, identification of nanobioparticles, viruses is proposed. Elaboration of relevant models of viruses, estimation of spectral response on interaction of electromagnetic (EM) field and viral nanoparticle is the goal of proposed methodology. Core-shell physical model is used as the first approximation of shape-structure of virion. Theoretical solution of EM wave scattering on single spherical virus-like particle (VLP) is applied for determination of EM fields in the areas of core, shell and surrounding medium of (VLP), as well as scattering and absorption characteristics. Numerical results obtained by computer simulation for estimation of EM “spectra” of bacteriophage T7 demonstrate the strong dependence of spectroscopic characteristics on core-shell related electric and geometric parameters of VLP in resonance wavelengths range. Expected spectral response is observable on far-field characterizations. Obtained analytical EM field expressions, modelling technique in complement with experimental spectroscopic methods should be the way of providing the virus spectral signatures, important in bioparticles characterization.

Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

PubMed Central

Bergmair, Michael; Bruno, Giovanni; Cattelan, Denis; Cobet, Christoph; de Martino, Antonello; Fleischer, Karsten; Dohcevic-Mitrovic, Zorana; Esser, Norbert; Galliet, Melanie; Gajic, Rados; Hemzal, Dušan; Hingerl, Kurt; Humlicek, Josef; Ossikovski, Razvigor; Popovic, Zoran V.; Saxl, Ottilia

2009-01-01

This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures. PMID:21170135

Direct Determination of Nonmetals in Solution with Atomic Spectrometry.

ERIC Educational Resources Information Center

McGregor, David A.; And Others

1988-01-01

Addresses solution nonmetal determinations on a fundamental level. Characterizes research in this area of chemical instrumentation. Discusses the fundamental limitations of nonmetal atomic spectrometry, the status of nonmetals and atomic spectroscopic techniques, and current directions in solution nonmetal determinations. (CW)

One-step multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by preparative capillary gas with characterization by spectroscopic and spectrometric techniques and evaluation of biological activity

USDA-ARS?s Scientific Manuscript database

In the present work multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by Preparative Capillary Gas Chromatography (PCGC) with characterization by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have been carried out. Gas chromatography (GC-FID) ...

The fifth solvatomorph of gallic acid with a supramolecular channel structure: Structural complexity and phase transitions

NASA Astrophysics Data System (ADS)

Thomas, Sajesh P.; Kaur, Ramanpreet; Kaur, Jassjot; Sankolli, Ravish; Nayak, Susanta K.; Guru Row, Tayur N.

2013-01-01

A new solvatomorph of gallic acid was generated using chiral additive technique and characterized by single crystal and powder X-ray diffraction, C-13 NMR, IR spectroscopic techniques and thermal analysis. The supramolecular channels formed by hexameric motifs of gallic acid and solvent molecules contain highly disordered solvent molecules with fractional occupancies.

Molecular Modeling of a Probe in 2D IR Spectroscopy

NASA Astrophysics Data System (ADS)

Cooper, Anthony; Larini, Luca

Proteins must adopt a precise three dimensional structure in the folding process in order to perform its designated function. Although much has been learned about folding, there are still many details in structural dynamics that are difficult to characterize by existing experimental techniques. In order to overcome these challenges, novel infrared and fluorescent spectroscopic techniques have recently been employed to probe the molecular structure at the atomistic scale. These techniques rely on the spectroscopic properties of the nitrile group attached to a phenylalanine. In this study, we model this probe and we compute its properties in different solvents. This is done by performing Molecular Dynamics simulations with a PheCN solvated in water, urea and TMAO. We measure the decay rate of the vibrational stretching of the CN group in order to characterize the effects of different solvents on the local structure of the molecule. This data can be used to identify non-trivial conformational changes of the protein in the folding process. Preliminary results show agreement with current experimental data on 2D IR spectroscopy.

A Tape Method for Fast Characterization and Identification of Active Pharmaceutical Ingredients in the 2-18 THz Spectral Range

NASA Astrophysics Data System (ADS)

Kissi, Eric Ofosu; Bawuah, Prince; Silfsten, Pertti; Peiponen, Kai-Erik

2015-03-01

In order to find counterfeit drugs quickly and reliably, we have developed `tape method' a transmission spectroscopic terahertz (THz) measurement technique and compared it with a standard attenuated total reflection (ATR) THz spectroscopic measurement. We used well-known training samples, which include commercial paracetamol and aspirin tablets to check the validity of these two measurement techniques. In this study, the spectral features of some active pharmaceutical ingredients (APIs), such as aspirin and paracetamol are characterized for identification purpose. This work covers a wide THz spectral range namely, 2-18 THz. This proposed simple but novel technique, the tape method, was used for characterizing API and identifying their presence in their dosage forms. By comparing the spectra of the APIs to their dosage forms (powder samples), all distinct fingerprints present in the APIs are also present in their respective dosage forms. The positions of the spectral features obtained with the ATR techniques were akin to that obtained from the tape method. The ATR and the tape method therefore, complement each other. The presence of distinct fingerprints in this spectral range has highlighted the possibility of developing fast THz sensors for the screening of pharmaceuticals. It is worth noting that, the ATR method is applicable to flat faced tablets whereas the tape method is suitable for powders in general (e.g. curved surface tablets that require milling before measurement). Finally, we have demonstrated that ATR techniques can be used to screen counterfeit antimalarial tablets.

Screening concepts, characterization and structural analysis of microbial-derived bioactive lipopeptides: a review.

PubMed

Biniarz, Piotr; Łukaszewicz, Marcin; Janek, Tomasz

2017-05-01

Lipopeptide biosurfactants are surface active biomolecules that are produced by a variety of microorganisms. Microbial lipopeptides have gained the interest of microbiologists, chemists and biochemists for their high biodiversity as well as efficient action, low toxicity and good biodegradability in comparison to synthetic counterparts. In this report, we review methods for the production, isolation and screening, purification and structural characterization of microbial lipopeptides. Several techniques are currently available for each step, and we describe the most commonly utilized and recently developed techniques in this review. Investigations on lipopeptide biosurfactants in natural products require efficient isolation techniques for the characterization and evaluation of chemical and biological properties. A combination of chromatographic and spectroscopic techniques offer opportunities for a better characterization of lipopeptide structures, which in turn can lead to the application of lipopeptides in food, pharmaceutical, cosmetics, agricultural and bioremediation industries.

Complementarity in radiochemical and infrared spectroscopic characterization of electrode adsorption

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

Wieckowski, A.

1994-03-01

Radioactive labelling and infrared spectroscopy are frequently used as direct, in situ probes into the structure of the electrochemical solid/liquid interface. These techniques are compared, in a polemical fashion, in the context of a recent publication by Parry et al. (Langmuir 1993, 9, 1878) where the research potential of the former technique was not adequately depicted. It is shown that radiotracers can clearly differentiate between the surface and solution species, both neutrals and anions. In addition to the surface specificity, the radiotracers offer a quantitative determination of adsorbate surface concentrations, a feature not yet demonstrated with surface infrared spectroscopy inmore » electrochemistry. Therefore, these two techniques are complementary. Examples of the combined radiochemical and spectroscopic measurements of adsorption with equivalent (smooth) electrode surfaces are quoted. 11 refs., 2 figs.« less

Synthesis and Characterization of 1,4-Dihydro-3,1-Benzoxazines and 1,2,3,4-Tetrahydroquinazolines: An Unknown Structure Determination Experiment

ERIC Educational Resources Information Center

Bendorf, Holly D.; Vebrosky, Emily N.; Eck, Brian J.

2016-01-01

In this experiment for an upper-division course in organic structure determination, each student prepares an unknown compound and characterizes the product using multiple spectroscopic techniques. The unknowns, 2-aryl-substituted 1,4-dihydro-3,1-benzoxazines and 1,2,3,4-tetrahydroquinazolines, are prepared in a single step by the condensation of…

Comparison between non-invasive methods used on paintings by Goya and his contemporaries: hyperspectral imaging vs. point-by-point spectroscopic analysis.

PubMed

Daniel, Floréal; Mounier, Aurélie; Pérez-Arantegui, Josefina; Pardos, Carlos; Prieto-Taboada, Nagore; Fdez-Ortiz de Vallejuelo, Silvia; Castro, Kepa

2017-06-01

The development of non-invasive techniques for the characterization of pigments is crucial in order to preserve the integrity of the artwork. In this sense, the usefulness of hyperspectral imaging was demonstrated. It allows pigment characterization of the whole painting. However, it also sometimes requires the complementation of other point-by-point techniques. In the present article, the advantages of hyperspectral imaging over point-by-point spectroscopic analysis were evaluated. For that purpose, three paintings were analysed by hyperspectral imaging, handheld X-ray fluorescence and handheld Raman spectroscopy in order to determine the best non-invasive technique for pigment identifications. Thanks to this work, the main pigments used in Aragonese artworks, and especially in Goya's paintings, were identified and mapped by imaging reflection spectroscopy. All the analysed pigments corresponded to those used at the time of Goya. Regarding the techniques used, the information obtained by the hyperspectral imaging and point-by-point analysis has been, in general, different and complementary. Given this fact, selecting only one technique is not recommended, and the present work demonstrates the usefulness of the combination of all the techniques used as the best non-invasive methodology for the pigments' characterization. Moreover, the proposed methodology is a relatively quick procedure that allows a larger number of Goya's paintings in the museum to be surveyed, increasing the possibility of obtaining significant results and providing a chance for extensive comparisons, which are relevant from the point of view of art history issues.

Function of minerals in the natural radioactivity level of Vaigai River sediments, Tamilnadu, India--spectroscopical approach.

PubMed

Ramasamy, V; Paramasivam, K; Suresh, G; Jose, M T

2014-01-03

Using Gamma ray and Fourier Transform Infrared (FTIR) spectroscopic techniques, level of natural radioactivity ((238)U, (232)Th and (40)K) and mineralogical characterization of Vaigai River sediments have been analyzed with the view of evaluating the radiation risk and its relation to available minerals. Different radiological parameters are calculated to know the entire radiological characterization. The average of activity concentrations and all radiological parameters are lower than the recommended safety limit. However, some sites are having higher radioactivity values than the safety limit. From the FTIR spectroscopic technique, the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, gibbsite, calcite, montmorillonite and organic carbon are identified and they are characterized. The extinction co-efficient values are calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index is calculated to know the crystalline nature of quartz and the result indicates that the presence of ordered crystalline quartz in the present sediment. The role of minerals in the level of radioactivity is assessed by multivariate statistical analysis (Pearson's correlation and Cluster analysis). The statistical analysis confirms that the clay mineral kaolinite is the major factor than other major minerals to induce the important radioactivity variables such as absorbed dose rate and concentrations of (232)Th and (238)U. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis, characterization, and application of novel biodegradable self-assembled 2-(N-phthalimido) ethyl-palmitate nanoparticles for cancer therapy

NASA Astrophysics Data System (ADS)

Kasoju, Naresh; Bora, Debajeet K.; Bhonde, Ramesh R.; Bora, Utpal

2010-03-01

We report the synthesis of novel biodegradable nanoparticles (NPs) which can kill the cancer cells without any additional drug loading. The NP was a self-assembled form of a phthalimide based conjugate, in which the phthalimide moiety was responsible for the anticancer activity. We describe the synthesis of a novel 2-(N-phthalimido) ethyl palmitate (PHEP-Pal) conjugate and subsequent preparation of NPs by a simple self assembly process. The successful synthesis of conjugate was confirmed by various characterization studies including nuclear magnetic resonance spectroscope, Fourier transform infrared spectroscope, TOF-liquid chromatography mass spectroscope, differential scanning calorimetry, and X-ray diffraction unit. The synthesis, shape, size, and size distribution of PHEP-Pal NPs were determined by transmission electron microscope, atomic force microscope, and dynamic light scattering technique. Finally, cell culture studies using A549 and HeLa cells were done to evaluate the anticancer effect of PHEP-Pal NPs, which demonstrated the potency of these NPs for use in cancer chemotherapy.

Large area fabrication of plasmonic nanoparticle grating structure by conventional scanning electron microscope

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

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.

Plasmonic nanoparticle grating (PNG) structure of different periods has been fabricated by electron beam lithography using silver halide based transmission electron microscope film as a substrate. Conventional scanning electron microscope is used as a fabrication tool for electron beam lithography. Optical microscope and energy dispersive spectroscopy (EDS) have been used for its morphological and elemental characterization. Optical characterization is performed by UV-Vis absorption spectroscopic technique.

Structural and spectroscopic changes to natural nontronite induced by experimental impacts between 10 and 40 GPa

NASA Astrophysics Data System (ADS)

Friedlander, Lonia R.; Glotch, Timothy D.; Bish, David L.; Dyar, M. Darby; Sharp, Thomas G.; Sklute, Elizabeth C.; Michalski, Joseph R.

2015-05-01

Many phyllosilicate deposits remotely detected on Mars occur within bombarded terrains. Shock metamorphism from meteor impacts alters mineral structures, producing changed mineral spectra. Thus, impacts have likely affected the spectra of remotely sensed Martian phyllosilicates. We present spectral analysis results for a natural nontronite sample before and after laboratory-generated impacts over five peak pressures between 10 and 40 GPa. We conducted a suite of spectroscopic analyses to characterize the sample's impact-induced structural and spectral changes. Nontronite becomes increasingly disordered with increasing peak impact pressure. Every infrared spectroscopic technique used showed evidence of structural changes at shock pressures above ~25 GPa. Reflectance spectroscopy in the visible near-infrared region is primarily sensitive to the vibrations of metal-OH and interlayer H2O groups in the nontronite octahedral sheet. Midinfrared (MIR) spectroscopic techniques are sensitive to the vibrations of silicon and oxygen in the nontronite tetrahedral sheet. Because the tetrahedral and octahedral sheets of nontronite deform differently, impact-driven structural deformation may contribute to differences in phyllosilicate detection between remote sensing techniques sensitive to different parts of the nontronite structure. Observed spectroscopic changes also indicated that the sample's octahedral and tetrahedral sheets were structurally deformed but not completely dehydroxylated. This finding is an important distinction from previous studies of thermally altered phyllosilicates in which dehydroxylation follows dehydration in a stepwise progression preceding structural deformation. Impact alteration may thus complicate mineral-specific identifications based on the location of OH-group bands in remotely detected spectra. This is a key implication for Martian remote sensing arising from our results.

The Catalyzed Substitution of CO by Isonitriles on (M(CO)6) (M=Cr, Mo, W).

ERIC Educational Resources Information Center

Albers, Michel O.; Singleton, Eric

1986-01-01

Describes experiments designed to: (1) familiarize students with inert atmosphere techniques; (2) teach monitoring reactions with thin-layer chromatography and infrared spectroscopy, isolation, and purification by crystallization and column chromatography; (3) estimate product purity spectroscopically; and (4) characterize reaction products by…

Polyoxygenated ursane and oleanane triterpenes from Siphonodon celastrineus.

PubMed

Kaweetripob, Wirongrong; Mahidol, Chulabhorn; Thongnest, Sanit; Prawat, Hunsa; Ruchirawat, Somsak

2016-09-01

Twenty polyoxygenated triterpenes, including nineteen ursanes and one oleanane, were characterized from the stem material of Siphonodon celastrineus (Celastraceae) through the application of spectroscopic techniques and chemical transformation. Three of the ursane-type triterpenoids possessed the rare 13,27-cyclopropane ring skeleton. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polarization interferometry for real-time spectroscopic plasmonic sensing.

PubMed

Otto, Lauren M; Mohr, Daniel A; Johnson, Timothy W; Oh, Sang-Hyun; Lindquist, Nathan C

2015-03-07

We present quantitative, spectroscopic polarization interferometry phase measurements on plasmonic surfaces for sensing applications. By adding a liquid crystal variable wave plate in our beam path, we are able to measure phase shifts due to small refractive index changes on the sensor surface. By scanning in a quick sequence, our technique is extended to demonstrate real-time measurements. While this optical technique is applicable to different sensor geometries-e.g., nanoparticles, nanogratings, or nanoapertures-the plasmonic sensors we use here consist of an ultrasmooth gold layer with buried linear gratings. Using these devices and our phase measurement technique, we calculate a figure of merit that shows improvement over measuring only surface plasmon resonance shifts from a reflected intensity spectrum. To demonstrate the general-purpose versatility of our phase-resolved measurements, we also show numerical simulations with another common device architecture: periodic plasmonic slits. Since our technique inherently measures both the intensity and phase of the reflected or transmitted light simultaneously, quantitative sensor device characterization is possible.

Synthesis, spectroscopic characterization and structural investigations of new adduct compound of carbazole with picric acid: DNA binding and antimicrobial studies

NASA Astrophysics Data System (ADS)

Saravanabhavan, Munusamy; Sathya, Krishnan; Puranik, Vedavati G.; Sekar, Marimuthu

2014-01-01

Carbazole picrate (CP), a new organic compound has been synthesized, characterized by various analytical and spectroscopic technique such as FT-IR, UV-Vis, 1H and 13C NMR spectroscopy. An orthorhombic geometry was proposed based on single crystal XRD study. The thermal stability of the crystal was studied by using thermo-gravimetric and differential thermal analyses and found that it was stable up to 170 °C. Further, the newly synthesized title compound was tested for its in vitro antibacterial and antifungal activity against various bacterial and fungal species. Also, the compound was tested for its binding activity with Calf thymus (CT) DNA and the results show a considerable interaction between CP and CT-DNA.

A newly synthesized thiazole derivative as a fluoride ion chemosensor: naked-eye, spectroscopic, electrochemical and NMR studies.

PubMed

Sarıgüney, Ahmet Burak; Saf, Ahmet Özgür; Coşkun, Ahmet

2014-07-15

2,3-Indoledione 3-thiosemicarbazone (TSCI) and a novel compound 3-(2-(4-(4-phenoxyphenyl)thiazol-2-yl)hydrazono)indolin-2-one (FTHI) were synthesized with high yield and characterized by spectroscopic techniques. The complexation behaviors of TSCI and FTHI for various anionic species (F(-), Cl(-), Br(-), I(-), NO2(-), NO3(-), BzO(-), HSO4(-), ClO4(-)) in CH3CN were investigated and compared by UV-vis spectroscopy, cyclic voltammetry and (1)H NMR titration techniques. FTHI showed high degree of selectivity for fluoride over other anions. This selectivity could be easily observed by the naked eye, indicating that FTHI is potential colorimetric sensor for fluoride anion. Copyright © 2014 Elsevier B.V. All rights reserved.

Structural and spectroscopic characterization, reactivity study and charge transfer analysis of the newly synthetized 2-(6-hydroxy-1-benzofuran-3-yl) acetic acid

NASA Astrophysics Data System (ADS)

Murthy, P. Krishna; Krishnaswamy, G.; Armaković, Stevan; Armaković, Sanja J.; Suchetan, P. A.; Desai, Nivedita R.; Suneetha, V.; SreenivasaRao, R.; Bhargavi, G.; Aruna Kumar, D. B.

2018-06-01

The title compound 2-(6-hydroxy-1-benzofuran-3-yl) acetic acid (abbreviated as HBFAA) has been synthetized and characterized by FT-IR, FT-Raman and NMR spectroscopic techniques. Solid state crystal structure of HBFAA has been determined by single crystal X-ray diffraction technique. The crystal structure features O-H⋯O and C-H⋯O intermolecular interactions resulting in a two dimensional supramolecular architecture. The presence of various intermolecular interactions is well supported by the Hirshfeld surface analysis. The molecular properties of HBFAA were performed by Density functional theory (DFT) using B3LYP/6-311G++(d,p) method at ground state in gas phase, compile these results with experimental values and shows mutual agreement. The vibrational spectral analysis were carried out using FT-IR and FT-Raman spectroscopic techniques and assignment of each vibrational wavenumber made on the basis of potential energy distribution (PED). And also frontier orbital analysis (FMOs), global reactivity descriptors, non-linear optical properties (NLO) and natural bond orbital analysis (NBO) of HBFAA were computed with same method. Efforts were made in order to understand global and local reactivity properties of title compound by calculations of MEP, ALIE, BDE and Fukui function surfaces in gas phase, together with thermodynamic properties. Molecular dynamics simulation and radial distribution functions were also used in order to understand the influence of water to the stability of title compound. Charge transfer between molecules of HBFAA has been investigated thanks to the combination of MD simulations and DFT calculations.

Multi-modular, tris(triphenylamine) zinc porphyrin-zinc phthalocyanine-fullerene conjugate as a broadband capturing, charge stabilizing, photosynthetic 'antenna-reaction center' mimic.

PubMed

Kc, Chandra B; Lim, Gary N; D'Souza, Francis

2015-04-21

A broadband capturing, charge stabilizing, photosynthetic antenna-reaction center model compound has been newly synthesized and characterized. The model compound is comprised of a zinc porphyrin covalently linked to three units of triphenylamine entities and a zinc phthalocyanine entity. The absorption and fluorescence spectra of zinc porphyrin complemented that of zinc phthalocyanine offering broadband coverage. Stepwise energy transfer from singlet excited triphenylamine to zinc porphyrin, and singlet excited zinc porphyrin to zinc phthalocyanine (kENT ∼ 10(11) s(-1)) was established from spectroscopic and time-resolved transient absorption techniques. Next, an electron acceptor, fullerene was introduced via metal-ligand axial coordination to both zinc porphyrin and zinc phthalocyanine centers, and they were characterized by spectroscopic and electrochemical techniques. An association constant of 4.9 × 10(4) M(-1) for phenylimidazole functionalized fullerene binding to zinc porphyrin, and 5.1 × 10(4) M(-1) for it binding to zinc phthalocyanine was obtained. An energy level diagram for the occurrence of different photochemical events within the multi-modular donor-acceptor conjugate was established from spectral and electrochemical data. Unlike the previous zinc porphyrin-zinc phthalocyanine-fullerene conjugates, the newly assembled donor-acceptor conjugate has been shown to undergo the much anticipated initial charge separation from singlet excited zinc porphyrin to the coordinated fullerene followed by a hole shift process to zinc phthalocyanine resulting in a long-lived charge separated state as revealed by femto- and nanosecond transient absorption spectroscopic techniques. The lifetime of the final charge separated state was about 100 ns.

Myoglobin structure and function: A multiweek biochemistry laboratory project.

PubMed

Silverstein, Todd P; Kirk, Sarah R; Meyer, Scott C; Holman, Karen L McFarlane

2015-01-01

We have developed a multiweek laboratory project in which students isolate myoglobin and characterize its structure, function, and redox state. The important laboratory techniques covered in this project include size-exclusion chromatography, electrophoresis, spectrophotometric titration, and FTIR spectroscopy. Regarding protein structure, students work with computer modeling and visualization of myoglobin and its homologues, after which they spectroscopically characterize its thermal denaturation. Students also study protein function (ligand binding equilibrium) and are instructed on topics in data analysis (calibration curves, nonlinear vs. linear regression). This upper division biochemistry laboratory project is a challenging and rewarding one that not only exposes students to a wide variety of important biochemical laboratory techniques but also ties those techniques together to work with a single readily available and easily characterized protein, myoglobin. © 2015 International Union of Biochemistry and Molecular Biology.

Exploring Raman spectroscopy for the evaluation of glaucomatous retinal changes

NASA Astrophysics Data System (ADS)

Wang, Qi; Grozdanic, Sinisa D.; Harper, Matthew M.; Hamouche, Nicolas; Kecova, Helga; Lazic, Tatjana; Yu, Chenxu

2011-10-01

Glaucoma is a chronic neurodegenerative disease characterized by apoptosis of retinal ganglion cells and subsequent loss of visual function. Early detection of glaucoma is critical for the prevention of permanent structural damage and irreversible vision loss. Raman spectroscopy is a technique that provides rapid biochemical characterization of tissues in a nondestructive and noninvasive fashion. In this study, we explored the potential of using Raman spectroscopy for detection of glaucomatous changes in vitro. Raman spectroscopic imaging was conducted on retinal tissues of dogs with hereditary glaucoma and healthy control dogs. The Raman spectra were subjected to multivariate discriminant analysis with a support vector machine algorithm, and a classification model was developed to differentiate disease tissues versus healthy tissues. Spectroscopic analysis of 105 retinal ganglion cells (RGCs) from glaucomatous dogs and 267 RGCs from healthy dogs revealed spectroscopic markers that differentiated glaucomatous specimens from healthy controls. Furthermore, the multivariate discriminant model differentiated healthy samples and glaucomatous samples with good accuracy [healthy 89.5% and glaucomatous 97.6% for the same breed (Basset Hounds); and healthy 85.0% and glaucomatous 85.5% for different breeds (Beagles versus Basset Hounds)]. Raman spectroscopic screening can be used for in vitro detection of glaucomatous changes in retinal tissue with a high specificity.

Characterization of plasmonic effects in thin films and metamaterials using spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Oates, T. W. H.; Wormeester, H.; Arwin, H.

2011-12-01

In this article, spectroscopic ellipsometry studies of plasmon resonances at metal-dielectric interfaces of thin films are reviewed. We show how ellipsometry provides valuable non-invasive amplitude and phase information from which one can determine the effective dielectric functions, and how these relate to the material nanostructure and define exactly the plasmonic characteristics of the system. There are three related plasmons that are observable using spectroscopic ellipsometry; volume plasmon resonances, surface plasmon polaritons and particle plasmon resonances. We demonstrate that the established method of exploiting surface plasmon polaritons for chemical and biological sensing may be enhanced using the ellipsometric phase information and provide a comprehensive theoretical basis for the technique. We show how the particle and volume plasmon resonances in the ellipsometric spectra of nanoparticle films are directly related to size, surface coverage and constituent dielectric functions of the nanoparticles. The regularly observed splitting of the particle plasmon resonance is theoretically described using modified effective medium theories within the framework of ellipsometry. We demonstrate the wealth of information available from real-time in situ spectroscopic ellipsometry measurements of metal film deposition, including the evolution of the plasmon resonances and percolation events. Finally, we discuss how generalized and Mueller matrix ellipsometry hold great potential for characterizing plasmonic metamaterials and sub-wavelength hole arrays.

Exploring Raman spectroscopy for the evaluation of glaucomatous retinal changes.

PubMed

Wang, Qi; Grozdanic, Sinisa D; Harper, Matthew M; Hamouche, Nicolas; Kecova, Helga; Lazic, Tatjana; Yu, Chenxu

2011-10-01

Glaucoma is a chronic neurodegenerative disease characterized by apoptosis of retinal ganglion cells and subsequent loss of visual function. Early detection of glaucoma is critical for the prevention of permanent structural damage and irreversible vision loss. Raman spectroscopy is a technique that provides rapid biochemical characterization of tissues in a nondestructive and noninvasive fashion. In this study, we explored the potential of using Raman spectroscopy for detection of glaucomatous changes in vitro. Raman spectroscopic imaging was conducted on retinal tissues of dogs with hereditary glaucoma and healthy control dogs. The Raman spectra were subjected to multivariate discriminant analysis with a support vector machine algorithm, and a classification model was developed to differentiate disease tissues versus healthy tissues. Spectroscopic analysis of 105 retinal ganglion cells (RGCs) from glaucomatous dogs and 267 RGCs from healthy dogs revealed spectroscopic markers that differentiated glaucomatous specimens from healthy controls. Furthermore, the multivariate discriminant model differentiated healthy samples and glaucomatous samples with good accuracy [healthy 89.5% and glaucomatous 97.6% for the same breed (Basset Hounds); and healthy 85.0% and glaucomatous 85.5% for different breeds (Beagles versus Basset Hounds)]. Raman spectroscopic screening can be used for in vitro detection of glaucomatous changes in retinal tissue with a high specificity.

Spectroscopic and molecular docking studies on the interaction of human serum albumin with copper(II) complexes

NASA Astrophysics Data System (ADS)

Guhathakurta, Bhargab; Pradhan, Ankur Bikash; Das, Suman; Bandyopadhyay, Nirmalya; Lu, Liping; Zhu, Miaoli; Naskar, Jnan Prakash

2017-02-01

Two osazone based ligands, butane-2,3-dione bis(2‧-pyridylhydrazone) (BDBPH) and hexane-3,4-dione bis(2‧-pyridylhydrazone) (HDBPH), were synthesized out of the 2:1 M Schiff base condensation of 2-hydrazino pyridine respectively with 2,3-butanedione and 3,4-hexanedione. The X-ray crystal structures of both the ligands have been determined. The copper(II) complex of HDBPH has also been synthesized and structurally characterized. HDBPH and its copper(II) complex have thoroughly been characterized through various spectroscopic and analytical techniques. The X-ray crystal structure of the copper complex of HDBPH shows that it is a monomeric Cu(II) complex having 'N4O2' co-ordination chromophore. Interaction of human serum albumin (HSA) with these ligands and their monomeric copper(II) complexes have been studied by various spectroscopic means. The experimental findings show that the ligands as well as their copper complexes are good HSA binders. Molecular docking investigations have also been done to unravel the mode of binding of the species with HSA.

Synthesis, spectroscopic characterization and structural investigations of new adduct compound of carbazole with picric acid: DNA binding and antimicrobial studies.

PubMed

Saravanabhavan, Munusamy; Sathya, Krishnan; Puranik, Vedavati G; Sekar, Marimuthu

2014-01-24

Carbazole picrate (CP), a new organic compound has been synthesized, characterized by various analytical and spectroscopic technique such as FT-IR, UV-Vis, (1)H and (13)C NMR spectroscopy. An orthorhombic geometry was proposed based on single crystal XRD study. The thermal stability of the crystal was studied by using thermo-gravimetric and differential thermal analyses and found that it was stable up to 170°C. Further, the newly synthesized title compound was tested for its in vitro antibacterial and antifungal activity against various bacterial and fungal species. Also, the compound was tested for its binding activity with Calf thymus (CT) DNA and the results show a considerable interaction between CP and CT-DNA. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel salicylic acid-oriented thiourea-type receptors as colorimetric chemosensor: Synthesis, characterizations and selective naked-eye recognition properties

NASA Astrophysics Data System (ADS)

Li, Shaowei; Cao, Xiufang; Chen, Changshui; Ke, Shaoyong

2012-10-01

Based on the salicylic acid backbone, three highly sensitive and selective colorimetric chemosensors with an acylthiourea binding unit have been designed, synthesized and characterized. These chemosensors have been utilized for selective recognition of fluoride anions in dry DMSO solution by typical spectroscopic titration techniques. Furthermore, the obtained chemosensors AR1-3 have shown naked-eye sensitivity for detection of biologically important fluoride ion over other anions in solution.

The application of visible absorption spectroscopy to the analysis of uranium in aqueous solutions

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

Colletti, Lisa Michelle; Copping, Roy; Garduno, Katherine

Through assay analysis into an excess of 1 M H 2SO 4 at fixed temperature a technique has been developed for uranium concentration analysis by visible absorption spectroscopy over an assay concentration range of 1.8 – 13.4 mgU/g. Once implemented for a particular spectrophotometer and set of spectroscopic cells this technique promises to provide more rapid results than a classical method such as Davies-Gray (DG) titration analysis. While not as accurate and precise as the DG method, a comparative analysis study reveals that the spectroscopic method can analyze for uranium in well characterized uranyl(VI) solution samples to within 0.3% ofmore » the DG results. For unknown uranium solutions in which sample purity is less well defined agreement between the developed spectroscopic method and DG analysis is within 0.5%. The technique can also be used to detect the presence of impurities that impact the colorimetric analysis, as confirmed through the analysis of ruthenium contamination. Finally, extending the technique to other assay solution, 1 M HNO 3, HCl and Na 2CO 3, has also been shown to be viable. As a result, of the four aqueous media the carbonate solution yields the largest molar absorptivity value at the most intensely absorbing band, with the least impact of temperature.« less

The application of visible absorption spectroscopy to the analysis of uranium in aqueous solutions

DOE PAGES

Colletti, Lisa Michelle; Copping, Roy; Garduno, Katherine; ...

2017-07-18

Through assay analysis into an excess of 1 M H 2SO 4 at fixed temperature a technique has been developed for uranium concentration analysis by visible absorption spectroscopy over an assay concentration range of 1.8 – 13.4 mgU/g. Once implemented for a particular spectrophotometer and set of spectroscopic cells this technique promises to provide more rapid results than a classical method such as Davies-Gray (DG) titration analysis. While not as accurate and precise as the DG method, a comparative analysis study reveals that the spectroscopic method can analyze for uranium in well characterized uranyl(VI) solution samples to within 0.3% ofmore » the DG results. For unknown uranium solutions in which sample purity is less well defined agreement between the developed spectroscopic method and DG analysis is within 0.5%. The technique can also be used to detect the presence of impurities that impact the colorimetric analysis, as confirmed through the analysis of ruthenium contamination. Finally, extending the technique to other assay solution, 1 M HNO 3, HCl and Na 2CO 3, has also been shown to be viable. As a result, of the four aqueous media the carbonate solution yields the largest molar absorptivity value at the most intensely absorbing band, with the least impact of temperature.« less

Near Field Imaging of Gallium Nitride Nanowires for Characterization of Minority Carrier Diffusion

DTIC Science & Technology

2009-12-01

diffusion length in nanowires is critical to potential applications in solar cells , spectroscopic sensing, and/or lasers and light emitting diodes (LED...technique has been successfully demonstrated with thin film solar cell materials [4, 5]. In these experiments, the diffusion length was measured using a...minority carrier diffusion length . This technique has been used in the near-field collection mode to image the diffusion of holes in n-type GaN

Raman Spectroscopic Imaging of the Whole Ciona intestinalis Embryo during Development

PubMed Central

Nakamura, Mitsuru J.; Hotta, Kohji; Oka, Kotaro

2013-01-01

Intracellular composition and the distribution of bio-molecules play central roles in the specification of cell fates and morphogenesis during embryogenesis. Consequently, investigation of changes in the expression and distribution of bio-molecules, especially mRNAs and proteins, is an important challenge in developmental biology. Raman spectroscopic imaging, a non-invasive and label-free technique, allows simultaneous imaging of the intracellular composition and distribution of multiple bio-molecules. In this study, we explored the application of Raman spectroscopic imaging in the whole Ciona intestinalis embryo during development. Analysis of Raman spectra scattered from C. intestinalis embryos revealed a number of localized patterns of high Raman intensity within the embryo. Based on the observed distribution of bio-molecules, we succeeded in identifying the location and structure of differentiated muscle and endoderm within the whole embryo, up to the tailbud stage, in a label-free manner. Furthermore, during cell differentiation, we detected significant differences in cell state between muscle/endoderm daughter cells and daughter cells with other fates that had divided from the same mother cells; this was achieved by focusing on the Raman intensity of single Raman bands at 1002 or 1526 cm−1, respectively. This study reports the first application of Raman spectroscopic imaging to the study of identifying and characterizing differentiating tissues in a whole chordate embryo. Our results suggest that Raman spectroscopic imaging is a feasible label-free technique for investigating the developmental process of the whole embryo of C. intestinalis. PMID:23977129

Advanced applications of scatterometry based optical metrology

NASA Astrophysics Data System (ADS)

Dixit, Dhairya; Keller, Nick; Kagalwala, Taher; Recchia, Fiona; Lifshitz, Yevgeny; Elia, Alexander; Todi, Vinit; Fronheiser, Jody; Vaid, Alok

2017-03-01

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, and lower cost per transistor. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require continuous development of metrology tools used for characterization of these complex 3D device architectures. Optical scatterometry or optical critical dimension (OCD) is one of the most prevalent inline metrology techniques in semiconductor manufacturing because it is a quick, precise and non-destructive metrology technique. However, at present OCD is predominantly used to measure the feature dimensions such as line-width, height, side-wall angle, etc. of the patterned nano structures. Use of optical scatterometry for characterizing defects such as pitch-walking, overlay, line edge roughness, etc. is fairly limited. Inspection of process induced abnormalities is a fundamental part of process yield improvement. It provides process engineers with important information about process errors, and consequently helps optimize materials and process parameters. Scatterometry is an averaging technique and extending it to measure the position of local process induced defectivity and feature-to-feature variation is extremely challenging. This report is an overview of applications and benefits of using optical scatterometry for characterizing defects such as pitch-walking, overlay and fin bending for advanced technology nodes beyond 7nm. Currently, the optical scatterometry is based on conventional spectroscopic ellipsometry and spectroscopic reflectometry measurements, but generalized ellipsometry or Mueller matrix spectroscopic ellipsometry data provides important, additional information about complex structures that exhibit anisotropy and depolarization effects. In addition the symmetry-antisymmetry properties associated with Mueller matrix (MM) elements provide an excellent means of measuring asymmetry present in the structure. The useful additional information as well as symmetry-antisymmetry properties of MM elements is used to characterize fin bending, overlay defects and design improvements in the OCD test structures are used to boost OCDs' sensitivity to pitch-walking. In addition, the validity of the OCD based results is established by comparing the results to the top down critical dimensionscanning electron microscope (CD-SEM) and cross-sectional transmission electron microscope (TEM) images.

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application.

PubMed

Fernández, José M; Plaza, César; Polo, Alfredo; Plante, Alain F

2012-01-01

The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO(2) respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structural Characterization of Sm(III)(EDTMP).

PubMed

Yang, Y; Pushie, M J; Cooper, D M L; Doschak, M R

2015-11-02

Samarium-153 ethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid) ((153)Sm-EDTMP, or samarium lexidronam), also known by its registered trademark name Quadramet, is an approved therapeutic radiopharmaceutical used in the palliative treatment of painful bone metastases. Typically, patients with prostate, breast, or lung cancer are most likely to go on to require bone pain palliation treatment due to bone metastases. Sm(EDTMP) is a bone-seeking drug which accumulates on rapidly growing bone, thereby delivering a highly region-specific dose of radiation, chiefly through β particle emission. Even with its widespread clinical use, the structure of Sm(EDTMP) has not yet been characterized at atomic resolution, despite attempts to crystallize the complex. Herein, we prepared a 1:1 complex of the cold (stable isotope) of Sm(EDTMP) under alkaline conditions and then isolated and characterized the complex using conventional spectroscopic techniques, as well as with extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional structure calculations, using natural abundance Sm. We present the atomic resolution structure of [Sm(III)(EDTMP)-8H](5-) for the first time, supported by the EXAFS data and complementary spectroscopic techniques, which demonstrate that the samarium coordination environment in solution is in agreement with the structure that has long been conjectured.

Non-destructive characterization of corroded glass surfaces by spectroscopic ellipsometry

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

Kaspar, Tiffany C.; Reiser, Joelle T.; Ryan, Joseph V.

Characterization of the alteration layers that form on glass surfaces during corrosion processes provides valuable information on both the mechanisms and rate of glass alteration. In recent years, state-of-the-art materials and surface characterization techniques have been employed to study various aspects of the alteration layers that result from corrosion. In most cases, these techniques are destructive and thus can only be employed at the end of the corrosion experiment. We show that the alteration layers can be investigated by non-destructive spectroscopic ellipsometry (SE), which provides pertinent information on alteration layer thickness, morphology, and, through correlation of the index of refraction,more » porosity. SE measurements of silicate glass coupons altered in aqueous solutions of pH 3, 5, 7, 9, and 11 at 90 °C for 7 days are compared to cross-sectional secondary electron microscopy images. In most cases, quantitative agreement of the alteration layer thickness is obtained. The fractional porosity calculated from the index of refraction is lower than the porosity calculated from elemental analysis of the aqueous solutions, indicating that the alteration layer has compacted during corrosion or the subsequent supercritical CO 2 drying process. Our results confirm the utility of performing non-destructive SE measurements on corroded glass surfaces.« less

Non-destructive characterization of corroded glass surfaces by spectroscopic ellipsometry

DOE PAGES

Kaspar, Tiffany C.; Reiser, Joelle T.; Ryan, Joseph V.; ...

2017-11-03

Characterization of the alteration layers that form on glass surfaces during corrosion processes provides valuable information on both the mechanisms and rate of glass alteration. In recent years, state-of-the-art materials and surface characterization techniques have been employed to study various aspects of the alteration layers that result from corrosion. In most cases, these techniques are destructive and thus can only be employed at the end of the corrosion experiment. We show that the alteration layers can be investigated by non-destructive spectroscopic ellipsometry (SE), which provides pertinent information on alteration layer thickness, morphology, and, through correlation of the index of refraction,more » porosity. SE measurements of silicate glass coupons altered in aqueous solutions of pH 3, 5, 7, 9, and 11 at 90 °C for 7 days are compared to cross-sectional secondary electron microscopy images. In most cases, quantitative agreement of the alteration layer thickness is obtained. The fractional porosity calculated from the index of refraction is lower than the porosity calculated from elemental analysis of the aqueous solutions, indicating that the alteration layer has compacted during corrosion or the subsequent supercritical CO 2 drying process. Our results confirm the utility of performing non-destructive SE measurements on corroded glass surfaces.« less

Detection of mercury ions using L-cysteine modified electrodes by anodic stripping voltammetric method

NASA Astrophysics Data System (ADS)

Vanitha, M.; Balasubramanian, N.; Joni, I. Made; Panatarani, Camellia

2018-02-01

The detection of contaminants in wastewater is of massive importance in today's situation as they pose a serious threat to the environment as well as humans. One such vital contaminants is mercury and its compound, the reported mercury detectors grieve from low sensitivity, high cost and slow response. In the present work graphene based electrode material is developed for sensing mercury contaminants in wastewater using electrochemical technique. The synthesized material graphene oxide (GO) modified with L-Cysteine in presence of polyvinylpyrrolidone (PVP) as capping agent was characterized using SEM, TEM and Raman Spectroscopic analysis. It is ascertained from the morphological characterization that the nanocomposite exhibits a spherical morphology. The L-cysteine modified graphene oxide electrode is electrochemically characterized using redox couple [Fe(CN)63-/4-] and electrochemical impedance spectroscopic (EIS) analysis. Electrochemical sensing of Hg (II) ions in solution was done using Square wave anodic stripping voltammetry (SWASV). The incorporation of graphene significantly increases the sensitivity and selectivity towards mercury sensing.

Nondestructive spectroscopic characterization of building materials

NASA Astrophysics Data System (ADS)

Kassu, Aschalew; Walker, Lauren; Sanders, Rachel; Farley, Carlton; Mills, Jonathan; Sharma, Anup

2017-04-01

The purpose of this research project is to demonstrate the application of Raman spectroscopy technique for characterization and identification of the distinct Raman signatures of construction materials. The results reported include the spectroscopic characterization of building materials using compact Raman system with 785 nm wavelength laser. The construction materials studied include polyblend sanded grout, fire barrier sealant, acrylic latex caulk plus and white silicone. It is found that, both fire barrier sealant and acrylic latex caulk plus has a prominent Raman band at 1082 cm-1, and three minor Raman signatures located at 275, 706 and 1436 cm-1. On the other hand, sand grout has three major Raman bands at 1265, 1368 and 1455 cm-1, and four minor peaks at 1573, 1683, 1762, and 1868 cm-1. White silicone, which is a widely used sealant material in construction industry, has two major Raman bands at 482 and 703 cm-1, and minor Raman characteristic bands at 783 and 1409 cm-1.

Mg co-ordination with potential carcinogenic molecule acrylamide: Spectroscopic, computational and cytotoxicity studies

NASA Astrophysics Data System (ADS)

Singh, Ranjana; Mishra, Vijay K.; Singh, Hemant K.; Sharma, Gunjan; Koch, Biplob; Singh, Bachcha; Singh, Ranjan K.

2018-03-01

Acrylamide (acr) is a potential toxic molecule produced in thermally processed food stuff. Acr-Mg complex has been synthesized chemically and characterized by spectroscopic techniques. The binding sites of acr with Mg were identified by experimental and computational methods. Both experimental and theoretical results suggest that Mg coordinated with the oxygen atom of Cdbnd O group of acr. In-vitro cytotoxicity studies revealed significant decrease in the toxic level of acr-Mg complex as compared to pure acr. The decrease in toxicity on complexation with Mg may be a useful step for future research to reduce the toxicity of acr.

Synthesis and structural characterization of new oxovanadium(IV) complexes derived from azo-5-pyrazolone with prospective medical importance

NASA Astrophysics Data System (ADS)

Bagdatli, Emine; Altuntas, Eylem; Sayin, Ulku

2017-01-01

Four novel o-hydroxy substituted aryl-(msbnd H, sbnd Cl, sbnd Br, sbnd CH3) azo-5-pyrazolone compounds (2a-d, respectively) were synthesized as azo-group containing ligands by diazotization of aryl amines then coupled with 1-(4-chlorophenyl)-3-isopropyl-1H-pyrazol-5(4H)-one (1) and the structures were confirmed by FTIR, UV-Visible, GC-MS or ESI-LCMS and NMR spectroscopic techniques. As a result, the first synthesis of azo-5-pyrazolone based oxovanadium(IV) complexes (3a-d) was achieved by interaction of 2a-d with half equivalent of vanadyl sulphate pentahydrate in a methanolic medium with moderate to high yields (67, 74, 60, 71 for 3a-d, respectively). The resulting complexes were characterized using FTIR, UV-Visible, ESI-LCMS and EPR spectroscopic techniques as well as with thermogravimetric (TG/DTG) analysis. They have the composition [VO(L)2]·H2O; (3a-c) or [VO(L)2]·CH3OH; (3d) where LH is an azo-5-pyrazolone compound as the ligand (2a-d). The electronic spectra of the complexes are typical of oxovanadium(IV) complexes showing a low intensity band near 500 nm. Spectroscopic results have shown that azo-5-pyrazolone compounds have acted bidendate and the coordination sites are hydroxyl-substituent on the -azo phenyl-aromatic ring and the pyrazolone carbonyl-moiety. The thermal data confirm that the complexes have methanol (3a-c) or water (3d) molecule outside the coordination sphere and the complexes show similar thermogravimetric decomposition fragments which are consistent with the proposed structures. A distorted octahedral geometry has been proposed for these complexes mainly with EPR and the other spectral techniques.

Synthesis, crystal structure and investigation of mononuclear copper(II) and zinc(II) complexes of a new carboxylate rich tripodal ligand and their interaction with carbohydrates in alkaline aqueous solution

PubMed Central

Stewart, Christopher D.; Pedraza, Mayra; Arman, Hadi; Fan, Hua-Jun; Schilling, Eduardo Luiz; Szpoganicz, Bruno; Musie, Ghezai T.

2016-01-01

A new carboxylate rich asymmetric tripodal ligand, N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine (H3camb), and its di-copper(II), (NH4)2[1]2, and di-zinc(II), ((CH3)4 N)2[2]2, complexes have been synthesized as carbohydrate binding models in aqueous solutions. The ligand and complexes have been fully characterized using several techniques, including single crystal X-ray diffraction. The interactions of (NH4)2[1]2 and ((CH3)4 N)2[2]2 with D-glucose, D-mannose, D-xylose and xylitol in aqueous alkaline media were investigated using UV–Vis and 13C-NMR spectroscopic techniques, respectively. The molar conductance, NMR and ESI–MS studies indicate that the complexes dissociate in solution to produce the respective complex anions, 1− and 2−. Complexes 1− and 2− showed chelating ability towards the naturally abundant and biologically relevant sugars, D-glucose, D-mannose, D-xylose, and xylitol. The complex ions bind to one molar equivalent of the sugars, even in the presence of stoichiometric excess of the substrates, in solution. Experimentally obtained spectroscopic data and computational results suggest that the substrates bind to the metal center in a bidentate fashion. Apparent binding constant values, pKapp, between the complexes and the substrates were determined and a specific mode of substrate binding is proposed. The pKapp and relativistic density functional theory (DFT) calculated Gibbs free energy values indicate that D-mannose displayed the strongest interaction with the complexes. Syntheses, characterizations, detailed substrate binding studies using spectroscopic techniques, single crystal X-ray diffraction and geometry optimizations of the complex-substrates with DFT calculations are also reported. PMID:25969174

Synthesis of samarium doped gadolinium oxide nanorods, its spectroscopic and physical properties

NASA Astrophysics Data System (ADS)

Boopathi, G.; Gokul Raj, S.; Ramesh Kumar, G.; Mohan, R.; Mohan, S.

2018-06-01

One-dimensional samarium doped gadolinium oxide [Sm:Gd2O3] nanorods have been synthesized successfully through co-precipitation technique in aqueous solution. The as-synthesized and calcined products were characterized by using powder X-ray diffraction pattern, Fourier transform Raman spectroscopy, thermogravimetric/differential thermal analysis, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, Ultraviolet-Visible spectrometry, photoluminescence spectrophotometer and X-ray photoelectron spectroscopy techniques. The obtained results are discussed in detailed manner.

Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

PubMed Central

Barazzouk, Saïd; Daneault, Claude

2012-01-01

In this work, oxidized nanocellulose (ONC) was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl) carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides) were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectroscopic techniques. PMID:28348303

Positron surface state as a spectroscopic probe for characterizing surfaces of topological insulator materials

NASA Astrophysics Data System (ADS)

Callewaert, Vincent; Shastry, K.; Saniz, Rolando; Makkonen, Ilja; Barbiellini, Bernardo; Assaf, Badih A.; Heiman, Donald; Moodera, Jagadeesh S.; Partoens, Bart; Bansil, Arun; Weiss, A. H.

2016-09-01

Topological insulators are attracting considerable interest due to their potential for technological applications and as platforms for exploring wide-ranging fundamental science questions. In order to exploit, fine-tune, control, and manipulate the topological surface states, spectroscopic tools which can effectively probe their properties are of key importance. Here, we demonstrate that positrons provide a sensitive probe for topological states and that the associated annihilation spectrum provides a technique for characterizing these states. Firm experimental evidence for the existence of a positron surface state near Bi2Te2Se with a binding energy of Eb=2.7 ±0.2 eV is presented and is confirmed by first-principles calculations. Additionally, the simulations predict a significant signal originating from annihilation with the topological surface states and show the feasibility to detect their spin texture through the use of spin-polarized positron beams.

An Iron(II)(1,3-bis(2'-pyridylimino)isoindoline) Complex as a Catalyst for Substrate Oxidation with H2O2. Evidence for a Transient Peroxodiiron(III) Species.

PubMed

Pap, József S; Cranswick, Matthew A; Balogh-Hergovich, E; Baráth, Gábor; Giorgi, Michel; Rohde, Gregory T; Kaizer, József; Speier, Gábor; Que, Lawrence

2013-08-01

The complex [Fe(indH)(solvent) 3 ](ClO 4 ) 2 ( 1 ) has been isolated from the reaction of equimolar amounts of 1,3-bis(2'-pyridylimino)isoindoline (indH) and Fe(ClO 4 ) 2 in acetonitrile and characterized by X-ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H 2 O 2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal-based oxidant. A metastable green species ( 2 ) is observed when 1 is reacted with H 2 O 2 at -40 °C, which has been characterized to have a Fe III ( μ -O)( μ -O 2 )Fe III core on the basis of UV-Vis, electron paramagnetic resonance, resonance Raman, and X-ray absorption spectroscopic data.

The synthesis and spectroscopic characterization of nano calcium fluorapatite using tetra-butylammonium fluoride

NASA Astrophysics Data System (ADS)

Sheykhan, Mehdi; Heydari, Akbar; Ma'mani, Leila; Badiei, Alireza

2011-12-01

Pure homogeneous nano sized biocompatible fluorapatite (FAp) particles were synthesized by a wet chemical procedure using water soluble tetra-butylammonium fluoride (TBAF) without using high temperatures and any purification processes. Combination of the Bragg's law and the plane-spacing equation for the two high intensity lines, namely, (0 0 2) and (3 0 0), gives a = 9.3531 Å, c = 6.8841 Å, confirms the identity of the highly crystalline synthetic material as well as its purity. The effect of various pH's in crystal formation and on their size was also evaluated. The calculated crystallinities were excellent with a rate around 5.0. The synthesized nano FAp was fully characterized by spectroscopic techniques (XRD, SEM, EDS, BET, FT-IR and ICP-AES). The nitrogen adsorption-desorption isotherm showed a type IV diagram and calculation of the surface area was investigated as well.

High sensitivity spectroscopic and thermal characterization of cooling efficiency for optical refrigeration materials

NASA Astrophysics Data System (ADS)

Melgaard, Seth D.; Seletskiy, Denis V.; Di Lieto, Alberto; Tonelli, Mauro; Sheik-Bahae, Mansoor

2012-03-01

Since recent demonstration of cryogenic optical refrigeration, a need for reliable characterization tools of cooling performance of different materials is in high demand. We present our experimental apparatus that allows for temperature and wavelength dependent characterization of the materials' cooling efficiency and is based on highly sensitive spectral differencing technique or two-band differential spectral metrology (2B-DSM). First characterization of a 5% w.t. ytterbium-doped YLF crystal showed quantitative agreement with the current laser cooling model, as well as measured a minimum achievable temperature (MAT) at 110 K. Other materials and ion concentrations are also investigated and reported here.

Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

NASA Astrophysics Data System (ADS)

Baier, S.; Rochet, A.; Hofmann, G.; Kraut, M.; Grunwaldt, J.-D.

2015-06-01

We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques.

PubMed

Baier, S; Rochet, A; Hofmann, G; Kraut, M; Grunwaldt, J-D

2015-06-01

We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

Intrinsic folding of small peptide chains: spectroscopic evidence for the formation of beta-turns in the gas phase.

PubMed

Chin, Wutharath; Dognon, Jean-Pierre; Piuzzi, François; Tardivel, Benjamin; Dimicoli, Iliana; Mons, Michel

2005-01-19

Laser desorption of model peptides coupled to laser spectroscopic techniques enables the gas-phase observation of genuine secondary structures of biology. Spectroscopic evidence for the formation of beta-turns in gas-phase peptide chains containing glycine and phenylalanine residues establishes the intrinsic stability of these forms and their ability to compete with other stable structures. The precise characterization of local minima on the potential energy surface from IR spectroscopy constitutes an acute assessment for the state-of-the-art quantum mechanical calculations also presented. The observation of different types of beta-turns depending upon the residue order within the sequence is found to be consistent with the residue propensities in beta-turns of proteins, which suggests that the prevalence of glycine in type II and II' turns stems essentially from an energetic origin, already at play under isolated conditions.

Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

PubMed Central

Kumirska, Jolanta; Czerwicka, Małgorzata; Kaczyński, Zbigniew; Bychowska, Anna; Brzozowski, Krzysztof; Thöming, Jorg; Stepnowski, Piotr

2010-01-01

Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. PMID:20559489

Synthesis, spectroscopic, single crystal diffraction and potential nonlinear optical properties of novel pyrazoline derivatives: Interplay of experimental and computational analyses.

PubMed

Arshad, Muhammad Nadeem; Birinji, Abdulhadi Salih; Khalid, Muhammad; Asiri, Abdullah M; Al-Amry, Khalid A; Aqlan, Faisal M S; Braga, Ataualpa A C

2018-09-05

Pyrazoline are widely being studied due to their potential applications in chemical field. Herein, five pyrazolines compounds were synthesized and characterized spectroscopically using nuclear magnetic resonance techniques ( 1 H NMR & 13 C NMR) to determine the structures of molecules along-with UV-Visible and infrared (FT-IR) studies for additional spectroscopic support in characterization of entitle synthesized molecules. Unit cells, specific space groups, bond lengths, bond angles and hydrogen bonding interactions were determined by the x-ray diffraction studies. Further, computational study of compounds with B3LYP/6-311 + G(d,p) level were carried out to explore optimized geometry, spectroscopic data for FT-IR, frontier molecular orbitals (FMOs) and non-linear optical (NLO) parameters. While, UV-Vis spectral were performed by TD-DFT/B3LYP/6-311 + G(d,p) level. The experimental results of spectroscopic and single crystal studies were compared and found in good agreement with the computational. The global reactivity parameters have been calculated with the help of the energy of FMOs. The order for the total first and second order hyperpolarizabilities of 1-5 is found in the following orders: 1 > 4 > 3 > 5 > 2 and 1 > 4 > 5 > 2 > 3 respectively. Overall, greater NLO response than urea molecule prove that investigated molecules are excellent candidate for NLO applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Detection and characterization of glaucoma-like canine retinal tissues using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Wang, Qi; Grozdanic, Sinisa D.; Harper, Matthew M.; Hamouche, Karl; Hamouche, Nicholas; Kecova, Helga; Lazic, Tatjana; Hernandez-Merino, Elena; Yu, Chenxu

2013-06-01

Early detection of pathological changes and progression in glaucoma and other neuroretinal diseases remains a great challenge and is critical to reduce permanent structural and functional retina and optic nerve damage. Raman spectroscopy is a sensitive technique that provides rapid biochemical characterization of tissues in a nondestructive and noninvasive fashion. In this study, spectroscopic analysis was conducted on the retinal tissues of seven beagles with acute elevation of intraocular pressure (AEIOP), six beagles with compressive optic neuropathy (CON), and five healthy beagles. Spectroscopic markers were identified associated with the different neuropathic conditions. Furthermore, the Raman spectra were subjected to multivariate discriminate analysis to classify independent tissue samples into diseased/healthy categories. The multivariate discriminant model yielded an average optimal classification accuracy of 72.6% for AEIOP and 63.4% for CON with 20 principal components being used that accounted for 87% of the total variance in the data set. A strong correlation (R2>0.92) was observed between pattern electroretinography characteristics of AEIOP dogs and Raman separation distance that measures the separation of spectra of diseased tissues from normal tissues; however, the underlining mechanism of this correlation remains to be understood. Since AEIOP mimics the pathological symptoms of acute/early-stage glaucoma, it was demonstrated that Raman spectroscopic screening has the potential to become a powerful tool for the detection and characterization of early-stage disease.

Shell-isolated nanoparticle-enhanced Raman spectroscopy study of the adsorption behaviour of DNA bases on Au(111) electrode surfaces.

PubMed

Wen, Bao-Ying; Jin, Xi; Li, Yue; Wang, Ya-Hao; Li, Chao-Yu; Liang, Miao-Miao; Panneerselvam, Rajapandiyan; Xu, Qing-Chi; Wu, De-Yin; Yang, Zhi-Lin; Li, Jian-Feng; Tian, Zhong-Qun

2016-06-21

For the first time, we used the electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (EC-SHINERS) technique to in situ characterize the adsorption behaviour of four DNA bases (adenine, guanine, thymine, and cytosine) on atomically flat Au(111) electrode surfaces. The spectroscopic results of the various molecules reveal similar features, such as the adsorption-induced reconstruction of the Au(111) surface and the drastic Raman intensity reduction of the ring breathing modes after the lifting reconstruction. As a preliminary study of the photo-induced charge transfer (PICT) mechanism, the in situ spectroscopic results obtained on single crystal surfaces are excellently illustrated with electrochemical data.

Spectroscopic analysis of 8-hydroxyquinoline derivatives and investigation of its reactive properties by DFT and molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Sureshkumar, B.; Mary, Y. Sheena; Resmi, K. S.; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Van Alsenoy, C.; Narayana, B.; Suma, S.

2018-03-01

Two 8-hydroxyquinoline derivatives, 5,7-dichloro-8-hydroxyquinoline (57DC8HQ) and 5-chloro-7-iodo-8-hydroxy quinoline (5CL7I8HQ) have been investigated in details by means of spectroscopic characterization and computational molecular modelling techniques. FT-IR and FT-Raman experimental spectroscopic approaches have been utilized in order to obtain detailed spectroscopic signatures of title compounds, while DFT calculations have been used in order to visualize and assign vibrations. The computed values of dipole moment, polarizability and hyperpolarizability indicate that the title molecules exhibit NLO properties. The evaluated HOMO and LUMO energies demonstrate the chemical stability of the molecules. NBO analysis is made to study the stability of the molecules arising from hyperconjugative interactions and charge delocalization. DFT calculations have been also used jointly with MD simulations in order to investigate in details global and local reactivity properties of title compounds. Also, molecular docking has been also used in order to investigate affinity of title compounds against decarboxylase inhibitor and quinoline derivatives can be a lead compounds for developing new antiparkinsonian drug.

X-ray Spectroscopic Characterization of Plasma for a Charged-Particle Energy-Loss Experiment

NASA Astrophysics Data System (ADS)

Hoffman, Nm; Lee, Cl; Wilson, Dc; Barnes, Cris W.; Petrasso, Rd; Li, C.; Hicks, D.

2000-10-01

We are pursuing an approach to a charged-particle energy-loss experiment in which charged fusion products from an imploded ICF capsule travel through a well characterized, spatially separate plasma. For this purpose, a fully ionized, uniform, nearly steady-state carbon-hydrogen plasma will be created by laser irradiation of a plastic foil. The temperature and density structure of this plasma must be determined accurately in order to relate observed energy losses to predictions of theory. Various methods for diagnosing the plasma are possible, including Thomson scattering. Alternatively, if a small admixture of higher-Z material such as chlorine is included in the plastic, x-ray spectroscopic techniques will allow the plasma's temperature and density to be determined. Electron temperature is inferred from the ratios of line strengths of various chlorine ion stages, while electron density is determined from the spectra of lithium-like satellite lines near the He beta line of helium-like chlorine. We present results from detailed-configuration accounting (DCA) models of line emission from C+H+Cl plasmas, and estimate the accuracy with which such plasmas can be characterized.

Positron annihilation lifetime characterization of oxygen ion irradiated rutile TiO2

NASA Astrophysics Data System (ADS)

Luitel, Homnath; Sarkar, A.; Chakrabarti, Mahuya; Chattopadhyay, S.; Asokan, K.; Sanyal, D.

2016-07-01

Ferromagnetic ordering at room temperature has been induced in rutile phase of TiO2 polycrystalline sample by O ion irradiation. 96 MeV O ion induced defects in rutile TiO2 sample has been characterized by positron annihilation spectroscopic techniques. Positron annihilation results indicate the formation of cation vacancy (VTi, Ti vacancy) in these irradiated TiO2 samples. Ab initio density functional theoretical calculations indicate that in TiO2 magnetic moment can be induced either by creating Ti or O vacancies.

Growth, structural, spectroscopic and optical characterization of barium doped calcium tartrate

NASA Astrophysics Data System (ADS)

Verma, Seema; Raina, Bindu; Gupta, Vandana; Bamzai, K. K.

2018-05-01

Barium doped calcium tartrates synthesized by controlled diffusion using silica gel technique at ambient temperature was characterized by single crystal X-ray diffraction which establishes monoclinic crystal system with volume of the unit cell 923.97(10) Ǻ3 and the space group being P21. UV - Vis characterization gives various linear optical constants like absorption, transmittance, reflectance, band gap, extinction coefficient, urbach energy, complex dielectric constant, optical and electrical conductivity. These constants are considered to be essential in characterizing materials that are used in various applications like fabrication of optoelectronic devices. FTIR spectrum establishes the presence of various bands of functional groups expected from metal tartrate with water of crystallization.

Synthesis, antitubercular and anticancer activities of substituted furyl-quinazolin-3(4H)-ones.

PubMed

Raghavendra, Nulgulmnalli M; Thampi, Parameshwaran; Gurubasavarajaswamy, Purvarga M; Sriram, Dharmarajan

2007-12-01

Some novel substituted-3-{[(1E)-(substituted-2-furyl)-methylene]amino}quinazolin-4(3H)-one (5, 6, 7) a-f were synthesized by a multi-step process. These synthesized compounds are characterized by various spectroscopic techniques and evaluated for their antitubercular and anticancer activities. Biological activity indicated that some of the title compounds are potent antitubercular and anticancer agents.

Quantum computational studies, spectroscopic (FT-IR, FT-Raman and UV-Vis) profiling, natural hybrid orbital and molecular docking analysis on 2,4 Dibromoaniline

NASA Astrophysics Data System (ADS)

Abraham, Christina Susan; Prasana, Johanan Christian; Muthu, S.; Rizwana B, Fathima; Raja, M.

2018-05-01

The research exploration will comprise of investigating the molecular structure, vibrational assignments, bonding and anti-bonding nature, nonlinear optical, electronic and thermodynamic nature of the molecule. The research is conducted at two levels: First level employs the spectroscopic techniques - FT-IR, FT-Raman and UV-Vis characterizing techniques; at second level the data attained experimentally is analyzed through theoretical methods using and Density Function Theories which involves the basic principle of solving the Schrodinger equation for many body systems. A comparison is drawn between the two levels and discussed. The probability of the title molecule being bio-active theoretically proved by the electrophilicity index leads to further property analyzes of the molecule. The target molecule is found to fit well with Centromere associated protein inhibitor using molecular docking techniques. Higher basis set 6-311++G(d,p) is used to attain results more concurrent to the experimental data. The results of the organic amine 2, 4 Dibromoaniline is analyzed and discussed.

Detection and Monitoring of Toxic Chemical at Ultra Trace Level by Utilizing Doped Nanomaterial

PubMed Central

Khan, Sher Bahadar; Rahman, Mohammed M.; Akhtar, Kalsoom; Asiri, Abdullah M.

2014-01-01

Composite nanoparticles were synthesized by eco-friendly hydrothermal process and characterized by different spectroscopic techniques. All the spectroscopic techniques suggested the synthesis of well crystalline optically active composite nanoparticles with average diameter of ∼30 nm. The synthesized nanoparticles were applied for the development of chemical sensor which was fabricated by coating the nanoparticles on silver electrode for the recognition of phthalimide using simple I–V technique. The developed sensor exhibited high sensitivity (1.7361 µA.mM−1.cm−2), lower detection limit (8.0 µM) and long range of detection (77.0 µM to 0.38 M). Further the resistances of composite nanoparticles based sensor was found to be 2.7 MΩ which change from 2.7 to 1.7 with change in phthalimide concentration. The major advantages of the designed sensor over existing sensors are its simple technique, low cost, lower detection limit, high sensitivity and long range of detection. It can detect phthalimide even at trace level and sense over wide range of concentrations. Therefore the composite nanoparticals would be a better choice for the fabrication of phthalimide chemical sensor and would be time and cost substituted implement for environmental safety. PMID:25329666

Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

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

Baier, S.; Rochet, A.; Hofmann, G.

2015-06-15

We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor formore » in situ studies.« less

Optical characterization of Mg-doped ZnO thin films deposited by RF magnetron sputtering technique

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

Singh, Satyendra Kumar; Tripathi, Shweta; Hazra, Purnima

2016-05-06

This paper reports the in-depth analysis on optical characteristics of magnesium (Mg) doped zinc oxide (ZnO) thin films grown on p-silicon (Si) substrates by RF magnetron sputtering technique. The variable angle ellipsometer is used for the optical characterization of as-deposited thin films. The optical reflectance, transmission spectra and thickness of as-deposited thin films are measured in the spectral range of 300-800 nm with the help of the spectroscopic ellipsometer. The effect of Mg-doping on optical parameters such as optical bandgap, absorption coefficient, absorbance, extinction coefficient, refractive Index and dielectric constant for as-deposited thin films are extracted to show its application inmore » optoelectronic and photonic devices.« less

Growth and properties of benzil doped benzimidazole (BMZ) single crystals

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

Babu, R. Ramesh, E-mail: rampap2k@yahoo.co.in; Crystal Growth and Crystallography Section, National Physical Laboratory, Krishnan Marg, New Delhi 110 012; Sukumar, M.

2010-09-15

In the present work, we have made an attempt to study the effect of benzil doping on the properties of benzimidazole single crystals. For this purpose we have grown pure and benzil doped benzimidazole single crystals by vertical Bridgman technique. The grown crystals were characterized by various characterization techniques. The presence of dopants confirmed by powder X-ray diffraction (XRD). Crystalline perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD). The transmittance, electrical property and mechanical strength have been analysed using UV-vis-NIR spectroscopic, dielectric and Vicker's hardness studies. The relative second harmonic generation efficiency of pure andmore » doped benzimidazole crystals measured using Kurtz powder test.« less

Spectroscopic ellipsometry analysis of a thin film composite membrane consisting of polysulfone on a porous α-alumina support.

PubMed

Ogieglo, Wojciech; Wormeester, Herbert; Wessling, Matthias; Benes, Nieck E

2012-02-01

Exposure of a thin polymer film to a fluid can affect properties of the film such as the density and thickness. In particular in membrane technology, these changes can have important implications for membrane performance. Spectroscopic ellipsometry is a convenient technique for in situ studies of thin films, because of its noninvasive character and very high precision. The applicability of spectroscopic ellipsometry is usually limited to samples with well-defined interfacial regions, whereas in typical composite membranes, often substantial and irregular intrusion of the thin film into the pores of a support exists. In this work, we provide a detailed characterization of a polished porous alumina membrane support, using variable-angle spectroscopic ellipsometry in combination with atomic force microscopy and mercury porosimetry. Two Spectroscopic ellipsometry optical models are presented that can adequately describe the surface roughness of the support. These models consider the surface roughness as a distinct layer in which the porosity gradually increases toward the outer ambient interface. The first model considers the porosity profile to be linear; the second model assumes an exponential profile. It is shown that the models can be extended to account for a composite membrane geometry, by deposition of a thin polysulfone film onto the support. The developed method facilitates practicability for in situ spectroscopic ellipsometry studies of nonequilibrium systems, i.e., membranes under actual permeation conditions.

Applications of UV/Vis Spectroscopy in Characterization and Catalytic Activity of Noble Metal Nanoparticles Fabricated in Responsive Polymer Microgels: A Review.

PubMed

Begum, Robina; Farooqi, Zahoor H; Naseem, Khalida; Ali, Faisal; Batool, Madeeha; Xiao, Jianliang; Irfan, Ahmad

2018-11-02

Noble metal nanoparticles loaded smart polymer microgels have gained much attention due to fascinating combination of their properties in a single system. These hybrid systems have been extensively used in biomedicines, photonics, and catalysis. Hybrid microgels are characterized by using various techniques but UV/Vis spectroscopy is an easily available technique for characterization of noble metal nanoparticles loaded microgels. This technique is widely used for determination of size and shape of metal nanoparticles. The tuning of optical properties of noble metal nanoparticles under various stimuli can be studied using UV/Vis spectroscopic method. Time course UV/Vis spectroscopy can also be used to monitor the kinetics of swelling and deswelling of microgels and hybrid microgels. Growth of metal nanoparticles in polymeric network or growth of polymeric network around metal nanoparticle core can be studied by using UV/Vis spectroscopy. This technique can also be used for investigation of various applications of hybrid materials in catalysis, photonics, and sensing. This tutorial review describes the uses of UV/Vis spectroscopy in characterization and catalytic applications of responsive hybrid microgels with respect to recent research progress in this area.

Copolymers of polyaniline and poly-o-toluidine: Electrochemical synthesis and characterization

NASA Astrophysics Data System (ADS)

Yadav, Pooja C.; Deshmukh, Megha A.; Patil, Harshada K.; Bodkhe, Gajanan A.; Sayyad, Pasha W.; Ingle, Nikesh N.; Shirsat, Mahendra D.

2018-05-01

In the present study we have reported Electrochemical polymerization of poly(Aniline) (PANI), Poly(O-Toluidine) (POT) and poly(Aniline-co-O-Toluidine) (PAOT) copolymers. Electrochemical Synthesis of PANI, POT and Poly(Aniline-co-O-Toluidine) was done by using Cyclic Voltammetry technique. The morphological study done by Atomic Force Microscopy (AFM) which shows that formation of uniform granular structure and topographic changes in each respective thin film. Spectroscopic characterization was done by FTIR spectroscopy. The FT-IR study revealed the formation of PANI/POT/Poly(Aniline co O-Toluidine) with a absorption band are reported. For structural information done by X-ray diffraction(XRD) Characterization.

Formation, Physicochemical Characterization, and Thermodynamic Stability of the Amorphous State of Drugs and Excipients.

PubMed

Martino, Piera Di; Magnoni, Federico; Peregrina, Dolores Vargas; Gigliobianco, Maria Rosa; Censi, Roberta; Malaj, Ledjan

2016-01-01

Drugs and excipients used for pharmaceutical applications generally exist in the solid (crystalline or amorphous) state, more rarely as liquid materials. In some cases, according to the physicochemical nature of the molecule, or as a consequence of specific technological processes, a compound may exist exclusively in the amorphous state. In other cases, as a consequence of specific treatments (freezing and spray drying, melting and co-melting, grinding and compression), the crystalline form may convert into a completely or partially amorphous form. An amorphous material shows physical and thermodynamic properties different from the corresponding crystalline form, with profound repercussions on its technological performance and biopharmaceutical properties. Several physicochemical techniques such as X-ray powder diffraction, thermal methods of analysis, spectroscopic techniques, gravimetric techniques, and inverse gas chromatography can be applied to characterize the amorphous form of a compound (drug or excipient), and to evaluate its thermodynamic stability. This review offers a survey of the technologies used to convert a crystalline solid into an amorphous form, and describes the most important techniques for characterizing the amorphous state of compounds of pharmaceutical interest.

Enzymatic and spectroscopic properties of a thermostable [NiFe]‑hydrogenase performing H2-driven NAD+-reduction in the presence of O2.

PubMed

Preissler, Janina; Wahlefeld, Stefan; Lorent, Christian; Teutloff, Christian; Horch, Marius; Lauterbach, Lars; Cramer, Stephen P; Zebger, Ingo; Lenz, Oliver

2018-01-01

Biocatalysts that mediate the H 2 -dependent reduction of NAD + to NADH are attractive from both a fundamental and applied perspective. Here we present the first biochemical and spectroscopic characterization of an NAD + -reducing [NiFe]‑hydrogenase that sustains catalytic activity at high temperatures and in the presence of O 2 , which usually acts as an inhibitor. We isolated and sequenced the four structural genes, hoxFUYH, encoding the soluble NAD + -reducing [NiFe]‑hydrogenase (SH) from the thermophilic betaproteobacterium, Hydrogenophilus thermoluteolus TH-1 T (Ht). The HtSH was recombinantly overproduced in a hydrogenase-free mutant of the well-studied, H 2 -oxidizing betaproteobacterium Ralstonia eutropha H16 (Re). The enzyme was purified and characterized with various biochemical and spectroscopic techniques. Highest H 2 -mediated NAD + reduction activity was observed at 80°C and pH6.5, and catalytic activity was found to be sustained at low O 2 concentrations. Infrared spectroscopic analyses revealed a spectral pattern for as-isolated HtSH that is remarkably different from those of the closely related ReSH and other [NiFe]‑hydrogenases. This indicates an unusual configuration of the oxidized catalytic center in HtSH. Complementary electron paramagnetic resonance spectroscopic analyses revealed spectral signatures similar to related NAD + -reducing [NiFe]‑hydrogenases. This study lays the groundwork for structural and functional analyses of the HtSH as well as application of this enzyme for H 2 -driven cofactor recycling under oxic conditions at elevated temperatures. Copyright © 2017 Elsevier B.V. All rights reserved.

Dielectric relaxation studies in Se{sub 90}Cd{sub 8}Sb{sub 2} glassy alloy

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

Shukla, Nitesh; Rao, Vandita; Dwivedi, D. K.

2016-05-06

Se{sub 90}Cd{sub 8}Sb{sub 2} chalcogenide semiconducting alloy was prepared by melt quench technique. The prepared glassy alloy has been characterized by techniques such as scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX).Dielectric properties of Se{sub 90}Cd{sub 8}Sb{sub 2} chalcogenide semiconductor have been studied using impedance spectroscopic technique in the frequency range 5×10{sup 2}Hz - 1×10{sup 5}Hz and in temperature range 303-318K. It is found that dielectric constant ε′ and dielectric loss factor ε″ are dependent on frequency and temperature.

Electrochromic TiO2 Thin Film Prepared by Dip-Coating Technique

NASA Astrophysics Data System (ADS)

Suriani, S.; Kamisah, M. M.

2002-12-01

Titanium dioxide (TiO2) thin films were prepared by using sol-gel dip coating technique. The coating solutions were prepared by reacting titanium isopropoxide as precursors and ethanol as solvent. The films were formed on transparent ITO-coated glass by a dip coating technique and final dried at various temperatures up to 600 °C for 30 minutes. The films were characterized with the UV-Vis-NIR Spectrometer, Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). XRD results show that the films dried at 600 °C form anatase structure. From the spectroscopic studies, the sample shows electrochromic property.

Structural study of Cu(II) complexes with benzo[b]furancarboxylic acids

NASA Astrophysics Data System (ADS)

Kalinowska, Diana; Klepka, Marcin T.; Wolska, Anna; Drzewiecka-Antonik, Aleksandra; Ostrowska, Kinga; Struga, Marta

2017-11-01

Four Cu(II) complexes with 2- and 3-benzo[b]furancarboxylic acids have been synthesized and characterized using combination of two spectroscopic techniques. These techniques were: (i) FTIR and (ii) XAFS. FTIR analysis confirmed that complexes were formed and gave insight into identification of possible coordinating groups to the metallic center. XANES analysis indicated that the oxidation state of Cu is +2. EXAFS analysis allowed to identify that the first coordination sphere is formed by 4-5 oxygen atoms with the Cu-O distances around 2 Å. Combining these techniques it was possible to structurally describe novel Cu(II) complexes with benzo[b]furancarboxylic acids.

Spectroscopic study of Pbs nano-structured layer prepared by Pld utilized as a Hall-effect magnetic sensor

NASA Astrophysics Data System (ADS)

Atwa, D. M.; Aboulfotoh, N.; El-magd, A. Abo; Badr, Y.

2013-10-01

Lead sulfide (PbS) nano-structured films have been grown on quartz substrates using PLD technique. The deposited films were characterized by several structural techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Selected-area electron diffraction patterns (SAED). The results prove the formation of cubic phase of PbS nanocrystals. Elemental analysis of the deposited films compared to the bulk target was obtained via laser induced fluorescence of the produced plasma particles and the energy dispersive X-ray "EDX" technique. The Hall coefficient measurements indicate an efficient performance of the deposited films as a magnetic sensor.

A Comparison of FTNMR and FTIR Techniques.

ERIC Educational Resources Information Center

Ahn, Myong-Ku

1989-01-01

Nuclear magnetic resonance and infrared are two spectroscopic methods that commonly use the Fourier transform technique. Discussed are the similarities and differences in the use of the Fourier transform in these two spectroscopic techniques. (CW)

Broadband mid-infrared and THz chemical detection with quantum cascade laser multi-heterodyne spectrometers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Westberg, Jonas; Sterczewski, Lukasz A.; Patrick, Link; Wysocki, Gerard

2017-05-01

Majority of chemical species of interest in security and safety applications (e.g. explosives) have complex molecular structures that produce unresolved rotational-vibrational spectroscopic signatures in the mid-infrared. This requires spectroscopic techniques that can provide broadband coverage in the mid-IR region to target broadband absorbers and high resolution to address small molecules that exhibit well-resolved spectral lines. On the other hand, many broadband mid-IR absorbers exhibit well-resolved rotational components in the THz spectral region. Thus, development of spectroscopic sensing technologies that can address both spectral regions is of great importance. Here we demonstrate recent progress towards broadband high-resolution spectroscopic sensing applications with Fabry-Perot quantum cascade lasers (QCLs) and frequency combs using multi-heterodyne spectroscopy (MHS) techniques. In this paper, we will present spectroscopic sensing of large and small molecules in the mid-IR region using QCLs operating at 8.5µm. An example high-resolution, broadband MHS of ammonia (small molecule) and isobutane (broadband absorber) at atmospheric pressure in the 1165-1190 cm^-1 range will be discussed. We have developed a balanced MHS system for mitigation of the laser intensity fluctuations. Absorption spectroscopy as well as dispersion spectroscopy with minimum fractional absorption down to 10^-4/Hz1/2 and fast spectral acquisition capabilities down to 10 µs/spectrum range will be demonstrated. In order to mitigate the shortcomings of the limited chemical selectivity in the mid-IR, THz QCL based spectrometer is currently under development to provide spectral de-congestion and thus significantly improve chemical identification. Preliminary characterization of the performance of THZ QCL combs for the THz QCL-MHS will be presented.

Time-frequency analysis in optical coherence tomography for technical objects examination

NASA Astrophysics Data System (ADS)

StrÄ kowski, Marcin R.; Kraszewski, Maciej; Trojanowski, Michał; Pluciński, Jerzy

2014-05-01

Optical coherence tomography (OCT) is one of the most advanced optical measurement techniques for complex structure visualization. The advantages of OCT have been used for surface and subsurface defect detection in composite materials, polymers, ceramics, non-metallic protective coatings, and many more. Our research activity has been focused on timefrequency spectroscopic analysis in OCT. It is based on time resolved spectral analysis of the backscattered optical signal delivered by the OCT. The time-frequency method gives spectral characteristic of optical radiation backscattered or backreflected from the particular points inside the tested device. This provides more information about the sample, which are useful for further analysis. Nowadays, the applications of spectroscopic analysis for composite layers characterization or tissue recognition have been reported. During our studies we have found new applications of spectroscopic analysis. We have used this method for thickness estimation of thin films, which are under the resolution of OCT. Also, we have combined the spectroscopic analysis with polarization sensitive OCT (PS-OCT). This approach enables to obtain a multiorder retardation value directly and may become a breakthrough in PS-OCT measurements of highly birefringent media. In this work, we present the time-frequency spectroscopic algorithms and their applications for OCT. Also, the theoretical simulations and measurement validation of this method are shown.

Vibrational spectroscopy reveals the initial steps of biological hydrogen evolution† †Electronic supplementary information (ESI) available: Complementary resonance Raman and infrared spectroscopic data. See DOI: 10.1039/c6sc01098a Click here for additional data file.

PubMed Central

Katz, S.; Noth, J.; Shafaat, H. S.; Happe, T.; Hildebrandt, P.

2016-01-01

[FeFe] hydrogenases are biocatalytic model systems for the exploitation and investigation of catalytic hydrogen evolution. Here, we used vibrational spectroscopic techniques to characterize, in detail, redox transformations of the [FeFe] and [4Fe4S] sub-sites of the catalytic centre (H-cluster) in a monomeric [FeFe] hydrogenase. Through the application of low-temperature resonance Raman spectroscopy, we discovered a novel metastable intermediate that is characterized by an oxidized [FeIFeII] centre and a reduced [4Fe4S]1+ cluster. Based on this unusual configuration, this species is assigned to the first, deprotonated H-cluster intermediate of the [FeFe] hydrogenase catalytic cycle. Providing insights into the sequence of initial reaction steps, the identification of this species represents a key finding towards the mechanistic understanding of biological hydrogen evolution. PMID:28451119

Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid.

PubMed

Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

2015-03-15

Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields. Copyright © 2014 Elsevier B.V. All rights reserved.

Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid

NASA Astrophysics Data System (ADS)

Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

2015-03-01

Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

In vivo Raman spectral pathology of human atherosclerosis and vulnerable plaque

NASA Astrophysics Data System (ADS)

Motz, Jason T.; Fitzmaurice, Maryann; Miller, Arnold; Gandhi, Saumil J.; Haka, Abigail S.; Galindo, Luis; Dasari, Ramachandra R.; Kramer, John R., Jr.; Feld, Michael S.

2006-03-01

The rupture of vulnerable atherosclerotic plaque accounts for the majority of clinically significant acute cardiovascular events. Because stability of these culprit lesions is directly related to chemical and morphological composition, Raman spectroscopy may be a useful technique for their study. Recent developments in optical fiber probe technology have allowed for the real-time in vivo Raman spectroscopic characterization of human atherosclerotic plaque demonstrated in this work. We spectroscopically examine 74 sites during carotid endarterectomy and femoral artery bypass surgeries. Of these, 34 are surgically biopsied and examined histologically. Excellent signal-to-noise ratio spectra are obtained in only 1 s and fit with an established model, demonstrating accurate tissue characterization. We also report the first evidence that Raman spectroscopy has the potential to identify vulnerable plaque, achieving a sensitivity and specificity of 79 and 85%, respectively. These initial findings indicate that Raman spectroscopy has the potential to be a clinically relevant diagnostic tool for studying cardiovascular disease.

Development of optical MEMS CO2 sensors

NASA Astrophysics Data System (ADS)

McNeal, Mark P.; Moelders, Nicholas; Pralle, Martin U.; Puscasu, Irina; Last, Lisa; Ho, William; Greenwald, Anton C.; Daly, James T.; Johnson, Edward A.; George, Thomas

2002-09-01

Inexpensive optical MEMS gas and chemical sensors offer chip-level solutions to environmental monitoring, industrial health and safety, indoor air quality, and automobile exhaust emissions monitoring. Previously, Ion Optics, Inc. reported on a new design concept exploiting Si-based suspended micro-bridge structures. The devices are fabricated using conventional CMOS compatible processes. The use of photonic bandgap (PBG) crystals enables narrow band IR emission for high chemical selectivity and sensitivity. Spectral tuning was accomplished by controlling symmetry and lattice spacing of the PBG structures. IR spectroscopic studies were used to characterize transmission, absorption and emission spectra in the 2 to 20 micrometers wavelength range. Prototype designs explored suspension architectures and filament geometries. Device characterization studies measured drive and emission power, temperature uniformity, and black body detectivity. Gas detection was achieved using non-dispersive infrared (NDIR) spectroscopic techniques, whereby target gas species were determined from comparison to referenced spectra. A sensor system employing the emitter/detector sensor-chip with gas cell and reflective optics is demonstrated and CO2 gas sensitivity limits are reported.

An Iron(II)(1,3-bis(2′-pyridylimino)isoindoline) Complex as a Catalyst for Substrate Oxidation with H2O2. Evidence for a Transient Peroxodiiron(III) Species

PubMed Central

Pap, József S.; Cranswick, Matthew A.; Balogh-Hergovich, É.; Baráth, Gábor; Giorgi, Michel; Rohde, Gregory T.; Kaizer, József; Speier, Gábor; Que, Lawrence

2014-01-01

The complex [Fe(indH)(solvent)3](ClO4)2 (1) has been isolated from the reaction of equimolar amounts of 1,3-bis(2′-pyridylimino)isoindoline (indH) and Fe(ClO4)2 in acetonitrile and characterized by X-ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H2O2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal-based oxidant. A metastable green species (2) is observed when 1 is reacted with H2O2 at −40 °C, which has been characterized to have a FeIII(μ-O)(μ-O2)FeIII core on the basis of UV-Vis, electron paramagnetic resonance, resonance Raman, and X-ray absorption spectroscopic data. PMID:24587695

RNA Characterization by Solid-State NMR Spectroscopy.

PubMed

Yang, Yufei; Wang, Shenlin

2018-06-21

The structures of RNAs, which play critical roles in various biological processes, provide important clues and insights into the biological functions of these molecules. However, RNA structure determination remains a challenging topic. In recent years, magic-angle-spinning solid-state NMR (MAS SSNMR) has emerged as an alternative technique for structural and dynamic characterization of RNA. MAS SSNMR has been successfully applied to provide atomic-level structural information about several RNA molecules and RNA-protein complexes. In this Minireview, we give an overview of recent progress in the field of MAS SSNMR based RNA structural characterization, and introduce sample preparation strategies and SSNMR spectroscopic techniques that have been incorporated to identify RNA structural elements. We also highlight a few impressive examples of RNAs that have been investigated extensively by SSNMR. Finally, we briefly discuss future technical trends in the use of MAS SSNMR to facilitate RNA structure determination. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of W/C soft x-ray multilayer mirror by ion beam sputtering (IBS) system for below 50A wavelength

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

Biswas, A.; Bhattacharyya, D.

A home-made Ion Beam Sputtering (IBS) system has been developed in our laboratory. Using the IBS system single layer W and single layer C film has been deposited at 1000eV Ar ion energy and 10mA ion current. The W-film has been characterized by grazing Incidence X-ray reflectrometry (GIXR) technique and Atomic Force Microscope technique. The single layer C-film has been characterized by Spectroscopic Ellipsometric technique. At the same deposition condition 25-layer W/C multilayer film has been deposited which has been designed for using as mirror at 30 Degree-Sign grazing incidence angle around 50A wavelength. The multilayer sample has been characterizedmore » by measuring reflectivity of CuK{alpha} radiation and soft x-ray radiation around 50A wavelength.« less

Optical characterization of agricultural pest insects: a methodological study in the spectral and time domains

NASA Astrophysics Data System (ADS)

Li, Y. Y.; Zhang, H.; Duan, Z.; Lian, M.; Zhao, G. Y.; Sun, X. H.; Hu, J. D.; Gao, L. N.; Feng, H. Q.; Svanberg, S.

2016-08-01

Identification of agricultural pest insects is an important aspect in insect research and agricultural monitoring. We have performed a methodological study of how spectroscopic techniques and wing-beat frequency analysis might provide relevant information. An optical system based on the combination of close-range remote sensing and reflectance spectroscopy was developed to study the optical characteristics of different flying insects, collected in Southern China. The results demonstrate that the combination of wing-beat frequency assessment and reflectance spectral analysis has the potential to successfully differentiate between insect species. Further, studies of spectroscopic characteristics of fixed specimen of insects, also from Central China, showed the possibility of refined agricultural pest identification. Here, in addition to reflectance recordings also laser-induced fluorescence spectra were investigated for all the species of insects under study and found to provide complementary information to optically distinguish insects. In order to prove the practicality of the techniques explored, clearly fieldwork aiming at elucidating the variability of parameters, even within species, must be performed.

Advancements in IR spectroscopic approaches for the determination of fungal derived contaminations in food crops.

PubMed

McMullin, David; Mizaikoff, Boris; Krska, Rudolf

2015-01-01

Infrared spectroscopy is a rapid, nondestructive analytical technique that can be applied to the authentication and characterization of food samples in high throughput. In particular, near infrared spectroscopy is commonly utilized in the food quality control industry to monitor the physical attributes of numerous cereal grains for protein, carbohydrate, and lipid content. IR-based methods require little sample preparation, labor, or technical competence if multivariate data mining techniques are implemented; however, they do require extensive calibration. Economically important crops are infected by fungi that can severely reduce crop yields and quality and, in addition, produce mycotoxins. Owing to the health risks associated with mycotoxins in the food chain, regulatory limits have been set by both national and international institutions for specific mycotoxins and mycotoxin classes. This article discusses the progress and potential of IR-based methods as an alternative to existing chemical methods for the determination of fungal contamination in crops, as well as emerging spectroscopic methods.

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

Sohn, H.; Camacho-Bunquin, J.; Langeslay, R. R.

Well-defined, isolated, single-site organovanadium(III) catalyst on SiO 2 [(SiO 2)V(Mes)(THF)] were synthesized via surface organometallic chemistry, and fully characterized using a combination of analytical and spectroscopic techniques (EA, ICP, 1H NMR, TGA-MS, EPR, XPS, DR-UV/Vis, UV-Raman, DRIFTS, XAS). The catalysts exhibit unprecedented reactivity in liquid- and gas-phase alkene/alkyne hydrogenation. Catalyst poisoning experiments revealed that 100% of the V sites are active for hydrogenation.

Synergetic effect of graphene oxide-carbon nanotube on nanomechanical properties of acrylonitrile butadiene styrene nanocomposites

NASA Astrophysics Data System (ADS)

Jyoti, Jeevan; Pratap Singh, Bhanu; Chockalingam, Sreekumar; Joshi, Amish G.; Gupta, Tejendra K.; Dhakate, S. R.

2018-04-01

Herein, multiwall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), graphene oxide-carbon nanotubes (GCNTs) hybrid reinforced acrylonitrile butadiene styrene (ABS) nanocomposites have been prepared by micro twin screw extruder with back flow channel and the effect of different type of fillers on the nanomechanical properties are studied. The combination of both graphene oxide and CNT has enhanced the dispersion in polymer matrix and lower the probability of CNTs aggregation. GCNTs hybrid have been synthesized via novel chemical route and well characterized using Raman spectroscopic technique. The nanoindentation hardness and elastic modulus of GCNTs-ABS hybrid nanocomposites were improved from 211.3 MPa and 4.12 GPa of neat ABS to 298.9 MPa and 6.02 GPa, respectively at 5wt% GCNTs loading. In addition to hardness and elastic modulus, other mechanical properties i.e. plastic index parameter, elastic recovery, ratio of residual displacement after load removal and displacement at the maximum load and plastic deformation energy have also been investigated. These results were correlated with Raman and X-ray photoelectron spectroscopic (XPS) techniques and microstructural characterizations (scanning electron microscopy). Our demonstration would provide guidelines for the fabrication of hard and scratches nanocomposite materials for potential use in, automotive trim components and bumper bars, carrying cases and electronic industries and electromagnetic interference shielding.

Novel acid mono azo dye compound: Synthesis, characterization, vibrational, optical and theoretical investigations of 2-[(E)-(8-hydroxyquinolin-5-yl)-diazenyl]-4,5-dimethoxybenzoic acid

NASA Astrophysics Data System (ADS)

Saçmacı, Mustafa; Çavuş, Hatice Kanbur; Arı, Hatice; Şahingöz, Recep; Özpozan, Talat

2012-11-01

Novel acid mono azo dye, 2-[(E)-(8-hydroxyquinolin-5yl)-diazenyl]-4,5-dimethoxybenzoic acid (HQD), was synthesized by coupling diazonium salt solution of 2-amino-4,5-dimethoxybenzoic acid (DMA) with 8-hydroxyquinoline (HQ). This dye was characterized by UV-vis, IR & Raman, 1H and 13C NMR spectroscopic techniques and elemental analysis. The normal coordinate analysis of HQD was also performed to assign each band in vibrational spectra. DFT (B3LYP and B3PW91) calculations were employed to optimize the geometry, to interpret NMR spectra, to calculate and to determine the stable tautomeric structure of the compound. Natural Bond Orbital (NBO) analysis was performed to investigate intramolecular interactions. The vibrational spectral data obtained from solid phase IR & Raman spectra were assigned based on the results of the theoretical calculations. UV-vis spectroscopic technique was employed to obtain the optical band gap of HQD. The analysis of the optical absorption data revealed the existence of direct and indirect transitions in the optical band gaps. The optical band gaps of HQD have been found 1.95 and 1.90 eV for direct and indirect transitions, respectively.

ENVIRONMENTAL APPLICATIONS OF RAMAN SPECTROSCOPY TO AQUEOUS SYSTEMS

EPA Science Inventory

The aim of this chapter is to demonstrate the great potential that the Raman spectroscopic technique offers for environmental applications, particularly to aqueous systems. We demonstrate the benefits of the technique relative to other information-rich spectroscopic techniques, i...

Infrared spectroscopic near-field mapping of single nanotransistors.

PubMed

Huber, A J; Wittborn, J; Hillenbrand, R

2010-06-11

We demonstrate the application of scattering-type scanning near-field optical microscopy (s-SNOM) for infrared (IR) spectroscopic material recognition in state-of-the-art semiconductor devices. In particular, we employ s-SNOM for imaging of industrial CMOS transistors with a resolution better than 20 nm, which allows for the first time IR spectroscopic recognition of amorphous SiO(2) and Si(3)N(4) components in a single transistor device. The experimentally recorded near-field spectral signature of amorphous SiO(2) shows excellent agreement with model calculations based on literature dielectric values, verifying that the characteristic near-field contrasts of SiO(2) stem from a phonon-polariton resonant near-field interaction between the probing tip and the SiO(2) nanostructures. Local material recognition by s-SNOM in combination with its capabilities of contact-free and non-invasive conductivity- and strain-mapping makes IR near-field microscopy a versatile metrology technique for nanoscale material characterization and semiconductor device analysis with application potential in research and development, failure analysis and reverse engineering.

Isolation, spectroscopic and density functional theory studies of 7-(4-methoxyphenyl)-9H-furo[2,3-f]chromen-9-one: a new flavonoid from the bark of Millettia ovalifolia.

PubMed

Taj Ur Rahman; Arfan, Mohammad; Mahmood, Tariq; Liaqat, Wajiha; Gilani, Mazhar Amjad; Uddin, Ghias; Ludwig, Ralf; Zaman, Khair; Choudhary, M Iqbal; Khattak, Khanzadi Fatima; Ayub, Khurshid

2015-07-05

The phytochemical examination of chloroform soluble fraction (FX2) of methanolic extract of bark of Millettia ovalifolia yielded a new flavonoid; 7-(4-methoxyphenyl)-9H-furo [2,3-f]chromen-9-one (1). Compound 1 is characterized by spectroscopic analytical techniques such as UV, IR, 1D, 2D NMR spectroscopy, and mass spectrometry. A theoretical model is also developed for obtaining geometric, electronic and spectroscopic properties of 1. The geometry optimization and harmonic vibration simulations have been carried out at B3LYP/6-31G(d,p). The vibrational spectrum of compound 1 shows nice correlation with the experimental IR spectrum, through a scaling factor of 0.9613. (1)H and (13)C NMR chemical shifts are simulated using Cramer's re-parameterized function WP04 at 6-31G(d,p) basis set, and correlate nicely with the experimental chemical shifts. Copyright © 2015 Elsevier B.V. All rights reserved.

Isolation, spectroscopic and density functional theory studies of 7-(4-methoxyphenyl)-9H-furo[2,3-f]chromen-9-one: A new flavonoid from the bark of Millettia ovalifolia

NASA Astrophysics Data System (ADS)

Rahman, Taj Ur; Arfan, Mohammad; Mahmood, Tariq; Liaqat, Wajiha; Gilani, Mazhar Amjad; Uddin, Ghias; Ludwig, Ralf; Zaman, Khair; Choudhary, M. Iqbal; Khattak, Khanzadi Fatima; Ayub, Khurshid

2015-07-01

The phytochemical examination of chloroform soluble fraction (FX2) of methanolic extract of bark of Millettia ovalifolia yielded a new flavonoid; 7-(4-methoxyphenyl)-9H-furo [2,3-f]chromen-9-one (1). Compound 1 is characterized by spectroscopic analytical techniques such as UV, IR, 1D, 2D NMR spectroscopy, and mass spectrometry. A theoretical model is also developed for obtaining geometric, electronic and spectroscopic properties of 1. The geometry optimization and harmonic vibration simulations have been carried out at B3LYP/6-31G(d,p). The vibrational spectrum of compound 1 shows nice correlation with the experimental IR spectrum, through a scaling factor of 0.9613. 1H and 13C NMR chemical shifts are simulated using Cramer's re-parameterized function WP04 at 6-31G(d,p) basis set, and correlate nicely with the experimental chemical shifts.

Spectroscopic investigation on structure and pH dependent Cocrystal formation between gamma-aminobutyric acid and benzoic acid

NASA Astrophysics Data System (ADS)

Du, Yong; Xue, Jiadan; Cai, Qiang; Zhang, Qi

2018-02-01

Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00 ≤ pH ≤ 7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields.

Synthesis and characterization of a novel schiff base of 1,2-diaminopropane with substituted salicyaldehyde and its transition metal complexes: Single crystal structures and biological activities

NASA Astrophysics Data System (ADS)

Tadavi, Samina K.; Yadav, Abhijit A.; Bendre, Ratnamala S.

2018-01-01

A novel schiff base H2L derived from simple condensation of 2-hydroxy-6-isopropyl-3-methyl benzaldehyde and 1,2-diaminopropane in 2:1 M ratio and its [MnL], [CoL] and [NiL]2 complexes have been prepared and characterized by spectroscopic technique, elemental analysis, SEM-EDX analysis, and cyclic voltammetry. Additionally, single crystal X-ray diffraction technique has been applied to the schiff base ligand H2L and its nickel complex. The structure of nickel complex exhibited dimeric form with formula [NiL]2 with distorted square planar geometry around each nickel center. Furthermore, all the synthesized compounds were screened for their antimicrobial and antioxidant and DNA cleavage activities.

Ag-doped CdO nanocatalysts: Preparation, characterization and catechol oxidase activity

NASA Astrophysics Data System (ADS)

El-Kemary, Maged; El-Mehasseb, Ibrahim; El-Shamy, Hany

2018-06-01

Silver doped cadmium oxide (Ag/CdO) nanoparticles with an average size of 41 nm have been successfully synthesized via thermal decomposition and liquid impregnation technique. The structural characterization has been performed by using several spectroscopic techniques, e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier-transform infrared (FT-IR). The catechol oxidase has been studied by UV-visible absorption spectroscopy and fourier-transform infrared as well as the mechanism has been assured by cyclic voltammetry and fluorescence spectroscopy. The results indicate that the oxidation does not occur in the presence of unsupported cadmium oxide particles by silver and in the same time, the catechol oxidase activity of silver doped CdO nanoparticles were improved by about three orders of magnitude than silver ions.

Raman Spectroscopy of Microbial Pigments

PubMed Central

Edwards, Howell G. M.; Oren, Aharon

2014-01-01

Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

Synthesis, spectroscopic characterization and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff bases derived from 5-bromo-salicylaldehyde

NASA Astrophysics Data System (ADS)

Kursunlu, Ahmed Nuri; Guler, Ersin; Sevgi, Fatih; Ozkalp, Birol

2013-09-01

In this study, the new Schiff base ligands derived from condensation of amine and 5-bromo-salicylaldehyde were characterized. All compounds, the Schiff bases and the metal complexes, were characterized by elemental analyzes, FT-IR, 1H NMR, 13C NMR and magnetic susceptibility measurements. The synthesized ligands, along with their metal (II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis) and four Gram-positive (Streptococcus pyogones, Bacillus cereus, Staphylococcus aureus and Methicillin-resistant S. aureus) bacterial strains by using disc diffusion and broth microdilution techniques.

HPLC-PFD determination of priority pollutant PAHs in water, sediment, and semipermeable membrane devices

USGS Publications Warehouse

Williamson, K.S.; Petty, J.D.; Huckins, J.N.; Lebo, J.A.; Kaiser, E.M.

2002-01-01

High performance liquid chromatography coupled with programmable fluorescence detection was employed for the determination of 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs) in water, sediment, and semipermeable membrane devices (SPMDs). Chromatographic separation using this analytical method facilitates selectivity, sensitivity (ppt levels), and can serve as a non-destructive technique for subsequent analysis by other chromatographic and spectroscopic techniques. Extraction and sample cleanup procedures were also developed for water, sediment, and SPMDs using various chromatographic and wet chemical methods. The focus of this publication is to examine the enrichment techniques and the analytical methodologies used in the isolation, characterization, and quantitation of 15 PPPAHs in different sample matrices.

Study of marbles from Middle Atlas (Morocco): elemental, mineralogical and structural analysis

NASA Astrophysics Data System (ADS)

Khrissi, S.; Bejjit, L.; Haddad, M.; Falguères, C.; Ait Lyazidi, S.; El Amraoui, M.

2018-05-01

A series of marbles sampled from the region of Middle Atlas (Morocco), are characterized by different complementary spectroscopic techniques. X-Ray fluorescence is used to determine elemental composition of rock while X-Ray diffraction and the Raman spectroscopy are used to determine major crystalline phases (calcite and dolomite) and minor ones (quartz).The samples display typical EPR spectra of Mn2+ in calcite and reveal the presence of Fe3+ ions.

Laser Spectroscopy Characterization of Materials for Frequency Agile Solid State Laser Systems

DTIC Science & Technology

1991-03-15

Lasing Properties of Nd3+:Ba2 ZnGe 2O 7 III. SPECTROSCOPIC PROPERTIES OF CHROMIUM -DOPED LASER CRYSTALS III.1 Laser-Induced Grating Spectroscopy of...rare earth- and chromium -doped Iasor crystals, rare earth-doped glasses, and potassium niobate. Ilas or- spectroscopy techniques were used to...being investigated: rare ea’-Lh-doped laser crystals; chromium -doped laser crystals; and photorefractive crystals and glasses. The important results

Calibration method for spectroscopic systems

DOEpatents

Sandison, David R.

1998-01-01

Calibration spots of optically-characterized material placed in the field of view of a spectroscopic system allow calibration of the spectroscopic system. Response from the calibration spots is measured and used to calibrate for varying spectroscopic system operating parameters. The accurate calibration achieved allows quantitative spectroscopic analysis of responses taken at different times, different excitation conditions, and of different targets.

Calibration method for spectroscopic systems

DOEpatents

Sandison, D.R.

1998-11-17

Calibration spots of optically-characterized material placed in the field of view of a spectroscopic system allow calibration of the spectroscopic system. Response from the calibration spots is measured and used to calibrate for varying spectroscopic system operating parameters. The accurate calibration achieved allows quantitative spectroscopic analysis of responses taken at different times, different excitation conditions, and of different targets. 3 figs.

High-pressure studies on nanocrystalline borderline Co1-xFexS2 (x = 0.4 and 0.5) using Mössbauer spectroscopic and electrical resistivity techniques up to 8 GPa

NASA Astrophysics Data System (ADS)

Chandra, Usha; Sharma, Pooja; Parthasarathy, G.

2016-12-01

Like bulk, Co1-xFexS2 nanoparticles also display an anomaly at x = 0.5. The borderline contiguous Co1-xFexS2 (x = 0.4 and 0.5) nanoparticles were synthesized with colloidal method and characterized for pyrite structure using various techniques, viz., X-ray diffraction, energy dispersive X-ray analysis (EDAX), S K-edge X-ray absorption near edge spectra, transmission electron microscopy (TEM) and Fourier transformed infra-red spectroscopy. The report presents the effect of high pressure on the borderline compositions using the Mössbauer spectroscopic and electrical resistivity techniques. Magnetic measurements on the system showed drastic lowering of Tc due to nanosize of the particles. With increased pressure, quadrupole splitting showed an expected trend of increase to attain a peak representing a second-order phase transition between 4 and 5 GPa for both the compositions. The pressure coefficient of electrical resistivity varied from -0.02 GPa to -0.06 GPa across transition pressure indicating a sluggish nature of transition. This is the first report of pressure effect on nanosized borderline compositions.

Synthesis, spectroscopic, and molecular structure characterizations of some azo derivatives of 2-hydroxyacetophenone

NASA Astrophysics Data System (ADS)

Albayrak, Çiğdem; Gümrükçüoğlu, İsmail E.; Odabaşoğlu, Mustafa; İskeleli, Nazan Ocak; Ağar, Erbil

2009-08-01

Some novel azo compounds were prepared by the reaction of 2-hydroxyacetophenone with aniline and its substituted derivatives. The structures of synthesized azo compounds were determined by IR, UV-Vis, 1H NMR and 13C NMR spectroscopic techniques and the structures of some of these compounds were also determined by X-ray diffraction studies. Structural analysis using IR in solid state shows that the azo form is favoured in the azo compounds whereas UV-Vis analysis of the azo compounds in solution has shown that there is a azo and ionic form. The azo compounds in the basic solvents dimethylformamide (DMF) and dimethylsulfoxide (DMSO) are both azo and ionic form while these compounds in ethyl alcohol (EtOH) and chloroform (CHCl 3) are only azo form.

Spectroscopic investigations of beam-plasma interactions in an ion plume

NASA Technical Reports Server (NTRS)

Ruyten, W. M.; Friedly, V. J.; Peng, X.; Celenza, J. A.; Keefer, D.

1993-01-01

We report the results of spectroscopic investigations of beam-plasma interactions in the plume from a 3 cm ion source operated on argon. Ion-electron, ion-neutral, and electron-neutral scattering are identified by studying the dependence of neutral and ion emission intensities on chamber pressure and mass flow rate, and by analyzing the emission lineshapes at a non-orthogonal angle to the plume axis. Through the Doppler shift, we are able to separate contributions from fast beam ions and fast charge-exchange neutrals on the one hand, and of slow neutrals and slow ions on the other. We discuss the application of this new technique to the characterization of beam plasma interactions in the downstream region of ion thruster engines, and its potential for identifying the processes which lead to grid erosion.

Spectroscopic analysis of roman wall paintings from Casa del Mitreo in Emerita Augusta, Mérida, Spain.

PubMed

Edreira, M C; Feliu, M J; Fernández-Lorenzo, C; Martín, J

2003-05-01

The use of visible spectroscopy, applied to chromatic characterization of Roman wall paintings, allows an easy and trustworthy grouping of the samples studied. The use of other spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS) in conjunction with X-ray diffraction (XRD) allows a good identification of the substances present in the pictorial layers that define and differentiate each chromatic group. In this paper, a study of 40 Roman wall painting samples, from Pinturas Báquicas of Casa del Mitreo in Emerita Augusta (Mérida, Spain), is described. In these samples, some pigments of high quality and cost, as well as some unusual mixtures, not described in the bibliography, have been found.

Spectroscopic characterization and quantitative determination of atorvastatin calcium impurities by novel HPLC method

NASA Astrophysics Data System (ADS)

Gupta, Lokesh Kumar

2012-11-01

Seven process related impurities were identified by LC-MS in the atorvastatin calcium drug substance. These impurities were identified by LC-MS. The structure of impurities was confirmed by modern spectroscopic techniques like 1H NMR and IR and physicochemical studies conducted by using synthesized authentic reference compounds. The synthesized reference samples of the impurity compounds were used for the quantitative HPLC determination. These impurities were detected by newly developed gradient, reverse phase high performance liquid chromatographic (HPLC) method. The system suitability of HPLC analysis established the validity of the separation. The analytical method was validated according to International Conference of Harmonization (ICH) with respect to specificity, precision, accuracy, linearity, robustness and stability of analytical solutions to demonstrate the power of newly developed HPLC method.

Spectroscopic Ellipsometry Studies of Ag and ZnO Thin Films and Their Interfaces for Thin Film Photovoltaics

NASA Astrophysics Data System (ADS)

Sainju, Deepak

Many modern optical and electronic devices, including photovoltaic devices, consist of multilayered thin film structures. Spectroscopic ellipsometry (SE) is a critically important characterization technique for such multilayers. SE can be applied to measure key parameters related to the structural, optical, and electrical properties of the components of multilayers with high accuracy and precision. One of the key advantages of this non-destructive technique is its capability of monitoring the growth dynamics of thin films in-situ and in real time with monolayer level precision. In this dissertation, the techniques of SE have been applied to study the component layer materials and structures used as back-reflectors and as the transparent contact layers in thin film photovoltaic technologies, including hydrogenated silicon (Si:H), copper indium-gallium diselenide (CIGS), and cadmium telluride (CdTe). The component layer materials, including silver and both intrinsic and doped zinc oxide, are fabricated on crystalline silicon and glass substrates using magnetron sputtering techniques. These thin films are measured in-situ and in real time as well as ex-situ by spectroscopic ellipsometry in order to extract parameters related to the structural properties, such as bulk layer thickness and surface roughness layer thickness and their time evolution, the latter information specific to real time measurements. The index of refraction and extinction coefficient or complex dielectric function of a single unknown layer can also be obtained from the measurement versus photon energy. Applying analytical expressions for these optical properties versus photon energy, parameters that describe electronic transport, such as electrical resistivity and electron scattering time, can be extracted. The SE technique is also performed as the sample is heated in order to derive the effects of annealing on the optical properties and derived electrical transport parameters, as well as the intrinsic temperature dependence of these properties and parameters. One of the major achievements of this dissertation research is the characterization of the thickness and optical properties of the interface layer formed between the silver and zinc oxide layers in a back-reflector structure used in thin film photovoltaics. An understanding of the impact of these thin film material properties on solar cell device performance has been complemented by applying reflectance and transmittance spectroscopy as well as simulations of cell performance.

A COMPARISON OF GALAXY COUNTING TECHNIQUES IN SPECTROSCOPICALLY UNDERSAMPLED REGIONS

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

Specian, Mike A.; Szalay, Alex S., E-mail: mspecia1@jhu.edu, E-mail: szalay@jhu.edu

2016-11-01

Accurate measures of galactic overdensities are invaluable for precision cosmology. Obtaining these measurements is complicated when members of one’s galaxy sample lack radial depths, most commonly derived via spectroscopic redshifts. In this paper, we utilize the Sloan Digital Sky Survey’s Main Galaxy Sample to compare seven methods of counting galaxies in cells when many of those galaxies lack redshifts. These methods fall into three categories: assigning galaxies discrete redshifts, scaling the numbers counted using regions’ spectroscopic completeness properties, and employing probabilistic techniques. We split spectroscopically undersampled regions into three types—those inside the spectroscopic footprint, those outside but adjacent to it,more » and those distant from it. Through Monte Carlo simulations, we demonstrate that the preferred counting techniques are a function of region type, cell size, and redshift. We conclude by reporting optimal counting strategies under a variety of conditions.« less

Applications of infrared photo-acoustic spectroscopy for wood samples

Treesearch

Mon-Lin Kuo; John F. McClelland; Siquan Luo; Po-Liang Chien; R.D. Walker; Chung-Yun Hse

1988-01-01

Various infrared (IR) spectroscopic techniques for the analysis of wood samples are briefly discussed. Theories and instrumentation of the newly developed photoacoustic spectroscopic (PAS) technique for measuring absorbance spectra of solids are presented. Some important applications of the PAS technique in wood science research are discussed. The application of the...

InP and GaAs characterization with variable stoichiometry obtained by molecular spray

NASA Technical Reports Server (NTRS)

Massies, J.; Linh, N. T.; Olivier, J.; Faulconnier, P.; Poirier, R.

1979-01-01

Both InP and GaAs surfaces were studied in parallel. A molecular spray technique was used to obtain two semiconductor surfaces with different superficial compositions. The structures of these surfaces were examined by electron diffraction. Electron energy loss was measured spectroscopically in order to determine surface electrical characteristics. The results are used to support conclusions relative to the role of surface composition in establishing a Schottky barrier effect in semiconductor devices.

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application

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

Fernandez, Jose M., E-mail: joseman@sas.upenn.edu; Plaza, Cesar; Polo, Alfredo

2012-01-15

Highlights: Black-Right-Pointing-Pointer Thermal analysis was used to assess stability and composition of organic matter in three diverse municipal waste streams. Black-Right-Pointing-Pointer Results were compared with C mineralization during 90-day incubation, FTIR and {sup 13}C NMR. Black-Right-Pointing-Pointer Thermal analysis reflected the differences between the organic wastes before and after the incubation. Black-Right-Pointing-Pointer The calculated energy density showed a strong correlation with cumulative respiration. Black-Right-Pointing-Pointer Conventional and thermal methods provide complimentary means of characterizing organic wastes. - Abstract: The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and providesmore » a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO{sub 2} respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts.« less

Label-free characterization of articular cartilage in osteoarthritis model mice by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Oshima, Yusuke; Akehi, Mayu; Kiyomatsu, Hiroshi; Miura, Hiromasa

2017-02-01

Osteoarthritis (OA) is very common joint disease in the aging population. Main symptom of OA is accompanied by degenerative changes of articular cartilage. Cartilage contains mostly type II collagen and proteoglycans, so it is difficult to access the quality and morphology of cartilage tissue in situ by conventional diagnostic tools (X-ray, MRI and echography) directly or indirectly. Raman spectroscopy is a label-free technique which enables to analyze molecular composition in degenerative cartilage. In this study, we generated an animal OA model surgically induced by knee joint instability, and the femurs were harvested at two weeks after the surgery. We performed Raman spectroscopic analysis for the articular cartilage of distal femurs in OA side and unaffected side in each mouse. In the result, there is no gross findings in the surface of the articular cartilage in OA. On the other hand, Raman spectral data of the articular cartilage showed drastic changes in comparison between OA and control side. The major finding of this study is that the relative intensity of phosphate band (960 cm-1) increases in the degenerative cartilage. This may be the result of exposure of subchondral bone due to thinning of the cartilage layer. In conclusion, Raman spectroscopic technique is sufficient to characterize articular cartilage in OA as a pilot study for Raman application in cartilage degeneration and regeneration using animal models and human subjects.

Detection and characterization of early plaque formations by Raman probe spectroscopy and optical coherence tomography: an in vivo study on a rabbit model

NASA Astrophysics Data System (ADS)

Matthäus, Christian; Dochow, Sebastian; Egodage, Kokila D.; Romeike, Bernd F.; Brehm, Bernhard R.; Popp, Jürgen

2018-01-01

Intravascular imaging techniques provide detailed specification about plaque appearance and morphology, but cannot deliver information about the biochemical composition of atherosclerotic plaques. As the biochemical composition is related to the plaque type, important aspects such as the risk of a plaque rupture and treatment are still difficult to assess. Currently, various spectroscopic techniques are tested for potential applications for the chemical analysis of plaque depositions. Here, we employ Raman spectroscopy in combination with optical coherence tomography (OCT) for the characterization of plaques on rabbits in vivo. Experiments were carried out on New Zealand white rabbits treated with a fat- and cholesterol-enriched diet, using a Raman probe setup with a 785-nm multimode laser as an excitation source. Subsequently, OCT images were acquired with a swept source at 1305±55 nm at 22.6 mW. Raman spectra were recorded from normal regions and regions with early plaque formations. The probe positioning was monitored by x-ray angiography. The spectral information identified plaque depositions consisting of lipids, with triglycerides as the major component. Afterward, OCT images of the spectroscopically investigated areas were obtained. The spectral information correlates well with the observed intravascular morphology and is in good agreement with histology. Raman spectroscopy can provide detailed biochemical specification of atherosclerotic plaques.

Solid-state reaction synthesis for mixed-phase Eu3+-doped bismuth molybdate and its luminescence properties

NASA Astrophysics Data System (ADS)

Liang, Danyang; Ding, Yu; Wang, Nan; Cai, Xiaomeng; Li, Jia; Han, Linyu; Wang, Shiqi; Han, Yuanyuan; Jia, Guang; Wang, Liyong

2017-09-01

A method for mixed-phase bismuth molybdate doped with Eu3+ ions was developed by solid-state reaction assisting with polyvinyl alcohol (PVA). The results of powder X-ray diffraction showed a mixed-phase structure and the microscopical characterization technology revealed the formation process with the addition of PVA. As a structure inducer, the PVA molecules played a vital role in the formation of phase structure. The as-obtained Eu3+-doped bismuth molybdates were also characterized by using different spectroscopic techniques including FTIR and photoluminescence (PL). The results show that doping concentration, PVA addition and calcination temperature affect photoluminescence properties remarkably.

Principle, system, and applications of tip-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, MingQian; Wang, Rui; Wu, XiaoBin; Wang, Jia

2012-08-01

Raman spectroscopy is a powerful technique in chemical information characterization. However, this spectral method is subject to two obstacles in nano-material detection. One is diffraction limited spatial resolution, and the other is its inherent small Raman cross section and weak signaling. To resolve these problems, a new approach has been developed, denoted as tip-enhanced Raman spectroscopy (TERS). TERS is capable of high-resolution and high-sensitivity detection and demonstrated to be a promising spectroscopic and micro-topographic method to characterize nano-materials and nanostructures. In this paper, the principle and experimental system of TERS are discussed. The latest application of TERS in molecule detection, biological specimen identification, nanao-material characterization, and semi-conductor material determination with some specific experimental examples are presented.

Synthesis, spectroscopic characterization and structural investigations of a new charge transfer complex of 2,6-diaminopyridine with 3,5-dinitrobenzoic acid: DNA binding and antimicrobial studies

NASA Astrophysics Data System (ADS)

Khan, Ishaat M.; Ahmad, Afaq; Kumar, Sarvendra

2013-03-01

A new charge transfer (CT) complex [(DAPH)+(DNB)-] consisting of 2,6-diaminopyridine (DAP) as donor and 3,5-dinitrobenzoic acid (DNB-H) as acceptor, was synthesized and characterized by FTIR, 1H and 13C NMR, ESI mass spectroscopic and X-ray crystallographic techniques. The hydrogen bonding (N+-H⋯O-) plays an important role to consolidate the cation and anion together. CT complex shows a considerable interaction with Calf thymus DNA. The CT complex was also tested for its antibacterial activity against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and two Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa strains by using Tetracycline as standard, and antifungal property against Aspergillus niger, Candida albicans, and Penicillium sp. by using Nystatin as standard. The results were compared with standard drugs and significant conclusions were obtained. A polymeric net work through H-bonding interactions between neighboring moieties was observed. This has been attributed to the formation of 1:1 type CT complex.

Accumulating the hydride state in the catalytic cycle of [FeFe]-hydrogenases

NASA Astrophysics Data System (ADS)

Winkler, Martin; Senger, Moritz; Duan, Jifu; Esselborn, Julian; Wittkamp, Florian; Hofmann, Eckhard; Apfel, Ulf-Peter; Stripp, Sven Timo; Happe, Thomas

2017-07-01

H2 turnover at the [FeFe]-hydrogenase cofactor (H-cluster) is assumed to follow a reversible heterolytic mechanism, first yielding a proton and a hydrido-species which again is double-oxidized to release another proton. Three of the four presumed catalytic intermediates (Hox, Hred/Hred and Hsred) were characterized, using various spectroscopic techniques. However, in catalytically active enzyme, the state containing the hydrido-species, which is eponymous for the proposed heterolytic mechanism, has yet only been speculated about. We use different strategies to trap and spectroscopically characterize this transient hydride state (Hhyd) for three wild-type [FeFe]-hydrogenases. Applying a novel set-up for real-time attenuated total-reflection Fourier-transform infrared spectroscopy, we monitor compositional changes in the state-specific infrared signatures of [FeFe]-hydrogenases, varying buffer pH and gas composition. We selectively enrich the equilibrium concentration of Hhyd, applying Le Chatelier's principle by simultaneously increasing substrate and product concentrations (H2/H+). Site-directed manipulation, targeting either the proton-transfer pathway or the adt ligand, significantly enhances Hhyd accumulation independent of pH.

Synthesis, characterization, antimicrobial activity and DFT studies of 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione and its Mn(II), Co(II), Ni(II) and Zn(II) complexes

NASA Astrophysics Data System (ADS)

Chioma, Festus; Ekennia, Anthony C.; Ibeji, Collins U.; Okafor, Sunday N.; Onwudiwe, Damian C.; Osowole, Aderoju A.; Ujam, Oguejiofo T.

2018-07-01

A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5-29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.

Binder free MnO2/PIn electrode material for supercapacitor application

NASA Astrophysics Data System (ADS)

Purty, B.; Choudhary, R. B.; Kandulna, R.; Singh, R.

2018-05-01

Electrochemically stable MnO2/PIn nanocomposite was synthesized via in-situ chemical oxidative polymerization process. The structural and morphological properties were studied through FTIR and FESEM characterizing techniques. Sphere like PIn and MnO2 nanorods offers interacting surface for charge transfer action. The electrochemical properties were investigated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopic (EIS) techniques. The significant enhancement in capacitance value with 95% coulombic efficiency and relatively low equivalent series resistance (ESR)˜0.4 Ω proved that MnO2/PIn nanocomposite is an excellent performer as an electrode material in the spectrum of supercapcitors and optoelectronic devices.

Noise characterization of broadband fiber Cherenkov radiation as a visible-wavelength source for optical coherence tomography and two-photon fluorescence microscopy.

PubMed

Tu, Haohua; Zhao, Youbo; Liu, Yuan; Liu, Yuan-Zhi; Boppart, Stephen

2014-08-25

Optical sources in the visible region immediately adjacent to the near-infrared biological optical window are preferred in imaging techniques such as spectroscopic optical coherence tomography of endogenous absorptive molecules and two-photon fluorescence microscopy of intrinsic fluorophores. However, existing sources based on fiber supercontinuum generation are known to have high relative intensity noise and low spectral coherence, which may degrade imaging performance. Here we compare the optical noise and pulse compressibility of three high-power fiber Cherenkov radiation sources developed recently, and evaluate their potential to replace the existing supercontinuum sources in these imaging techniques.

Synthesis and optical properties of polycrystalline Li2Al2B2O7 (LABO)

NASA Astrophysics Data System (ADS)

Dagdale, S. R.; Muley, G. G.

2016-05-01

A polycrystalline lithium aluminum borate (Li2Al2B2O7, LABO) has been synthesized by using simple solid-state technique. The obtained LABO polycrystalline was characterized by powder X-ray diffraction; Fourier transform infrared (FT-IR) spectroscopy and second harmonic generation (SHG) efficiency measurement. The functional groups were identified using the FT-IR spectroscopic data. The SHG efficiency of the polycrystalline material was obtained by the classic Kurtz powder technique using a fundamental wavelength 1064 nm of Nd:YAG laser and it is found to be 1.4 times that of potassium dihydrogen phosphate (KDP).

High-power laser with Nd:YAG single-crystal fiber grown by the micro-pulling-down technique

NASA Astrophysics Data System (ADS)

Didierjean, Julien; Castaing, Marc; Balembois, François; Georges, Patrick; Perrodin, Didier; Fourmigué, Jean Marie; Lebbou, Kherreddine; Brenier, Alain; Tillement, Olivier

2006-12-01

We present optical characterization and laser results achieved with single-crystal fibers directly grown by the micro-pulling-down technique. We investigate the spectroscopic and optical quality of the fiber, and we present the first laser results. We achieved a cw laser power of 10 W at 1064 nm for an incident pump power of 60 W at 808 nm and 360 kW peak power for 12 ns pulses at 1 kHz in the Q-switched regime. It is, to the best of our knowledge, the highest laser power ever achieved with directly grown single-crystal fibers.

Structural, spectral, DFT and biological studies on macrocyclic mononuclear ruthenium (II) complexes

NASA Astrophysics Data System (ADS)

Muthukkumar, M.; Kamal, C.; Venkatesh, G.; Kaya, C.; Kaya, S.; Enoch, Israel V. M. V.; Vennila, P.; Rajavel, R.

2017-11-01

Macrocyclic mononuclear ruthenium (II) complexes have been synthesized by condensation method [Ru (L1, L2, L3) Cl2] L1 = (C36 H31 N9), L2= (C42H36N8), L3= (C32H32 N8)]. These ruthenium complexes have been established by elemental analyses and spectroscopic techniques (Fourier transform infrared spectroscopy (FT-IR), 1H- nuclear magnetic resonance (NMR), 13C- NMR and Electrospray ionization mass spectrometry (ESI-MS)). The coordination mode of the ligand has been confirmed and the octahedral geometry around the ruthenium ion has been revealed. Binding affinity and binding mode of ruthenium (II) complexes with Bovine serum Albumin (BSA) have been characterized by Emission spectra analysis. UV-Visible and fluorescence spectroscopic techniques have also been utilized to examine the interaction between ligand and its complexes L1, L2, & L3 with BSA. Chemical parameters and molecular structure of Ru (II) complexes L1H, L2H, & L3H have been determined by DFT coupled with B3LYP/6-311G** functional in both the gaseous and aqueous phases.

Spectroscopic investigation into the design of solid-acid catalysts for the low temperature dehydration of ethanol.

PubMed

Potter, Matthew E; Aswegen, Sivan V; Gibson, Emma K; Silverwood, Ian P; Raja, Robert

2016-07-14

The increased demand for bulk hydrocarbons necessitates research into increasingly sustainable, energy-efficient catalytic processes. Owing to intricately designed structure-property correlations, SAPO-34 has become established as a promising material for the low temperature ethanol dehydration to produce ethylene. However, further optimization of this process requires a precise knowledge of the reaction mechanism at a molecular level. In order to achieve this a range of spectroscopic characterization techniques are required to probe both the interaction with the active site, and also the wider role of the framework. To this end we employ a combination of in situ infra-red and neutron scattering techniques to elucidate the influence of the surface ethoxy species in the activation of both diethyl ether and ethanol, towards the improved formation of ethylene at low temperatures. The combined conclusions of these studies is that the formation of ethylene is the rate determining step, which is of fundamental importance towards the development of this process and the introduction of bio-ethanol as a viable feedstock for ethylene production.

X-ray absorption spectroscopic studies on gold nanoparticles in mesoporous and microporous materials.

PubMed

Akolekar, Deepak B; Foran, Garry; Bhargava, Suresh K

2004-05-01

Au L(3)-edge X-ray absorption spectroscopic measurements were carried out over a series of mesoporous and microporous materials containing gold nanoparticles to investigate the effects of the host matrix and preparation methods on the properties of gold nanoparticles. The materials of structure type MCM-41, ZSM-5, SAPO-18 and LSX with varying framework composition containing low concentrations of gold nanoparticles were prepared and characterized. In these materials the size of the gold nanoparticles varied in the range approximately 1 to 4 nm. A series of gold nanoparticles within different mesoporous and microporous materials have been investigated using X-ray absorption fine structure (XANES, EXAFS) and other techniques. Information such as atomic distances, bonding and neighbouring environment obtained from XAFS measurements was useful in elucidating the nature and structure of gold nanoparticles on these catalytic materials. The influence of the high-temperature (823, 1113, 1273 K) treatment on gold nanoparticles inside the mesoporous matrix was investigated using the XAFS technique. The XAFS and XANES results confirm various characteristics of gold nanoparticles in these materials suitable for catalysis, fabrication of nanodevices and other applications.

Spectroscopic investigation on structure and pH dependent Cocrystal formation between gamma-aminobutyric acid and benzoic acid.

PubMed

Du, Yong; Xue, Jiadan; Cai, Qiang; Zhang, Qi

2018-02-15

Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00≤pH≤7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields. Copyright © 2017 Elsevier B.V. All rights reserved.

Green synthesis and characterization of alginate nanoparticles and its role as a biosorbent for Cr(VI) ions

NASA Astrophysics Data System (ADS)

Geetha, P.; Latha, M. S.; Pillai, Saumya S.; Deepa, B.; Santhosh Kumar, K.; Koshy, Mathew

2016-02-01

Green synthesis of nanoparticles has attained considerable attention in recent years because of its myriad of applications including drug delivery, tissue engineering and water purification. In the present study, alginate nanoparticles stabilized by honey were prepared by cross-linking aqueous solution of alginate with calcium ions. Honey mediated synthesis has been reported earlier for the production of metal nanoparticles. However no literature is available on the use of this technique for polymeric nanoparticles. Highly stable nanoparticles of 10-100 nm size were generated by this technique. The synthesised nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopic techniques. Potential of using these nanoparticles for heavy metal removal was studied by using Cr(VI) from aqueous solution, where a maximum removal efficiency of 93.5% was obtained. This method was also successfully employed for the production of other polymeric nanoparticles like casein, chitosan and albumin.

In-situ spectroscopic investigations of the redox behavior of poly(indole-5-carboxylic-acid) modified electrodes in acidic aqueous solutions.

PubMed

Talbi, H; Billaud, D; Louarn, G; Pron, A

2001-03-01

The oxidation of electrochemically grown poly(indole-5-carboxylic-acid) (P5CO2H) and its spectroscopic properties have been studied by in-situ spectroelectrochemical techniques. The purpose of this paper is to characterize the different modifications on the P5CO2H backbone, induced by the electrochemical oxidation in aqueous acidic solution. We have identified, on the basis of Raman spectra, the vibrational modes associated with neutral and oxidized segments of polymer. It was shown that at least three chemically and optically different species (perhaps other products too) are produced in different potential regimes upon oxidation of this polymer. The results obtained also indicate that the molecular properties of this conducting polymer are better revealed by in-situ resonant spectra than by ex-situ infrared and Raman studies.

The application of thermodynamic and spectroscopic techniques to adhesion in the polyimide/Ti 6-4 and polyphenylquinoxaline/Ti 6-4 systems

NASA Technical Reports Server (NTRS)

Dias, S.; Wightman, J. P.

1984-01-01

The results of calorimetric measurements of Ti adherend surfaces are presented. The measurements were carried out after several chemical pretreatments and after fracture of several lap shear samples aged at high temperature. The exact composition of the Ti samples was Ti(6 percent Al-4 percent V). The adhesives used were polyimides and polyphenylquinoxalines (PPQ). Each chemical pretreatment was accompanied by a unique spectroscopic feature which was characterized by XPS, SEM, and specular reflectance infrared spectroscopy. The energetics of the interaction between primer solutions and the Ti adherend were evaluated by microcalorimetry. Changes in the structure of the surface oxide layer upon heating of the adherend were deduced from immersion temperatures of the PI and PPQ solutions. The XPS and SEM data are given is a table.

Towards optical spectroscopic anatomical mapping (OSAM) for lesion validation in cardiac tissue (Conference Presentation)

NASA Astrophysics Data System (ADS)

Singh-Moon, Rajinder P.; Zaryab, Mohammad; Hendon, Christine P.

2017-02-01

Electroanatomical mapping (EAM) is an invaluable tool for guiding cardiac radiofrequency ablation (RFA) therapy. The principle roles of EAM is the identification of candidate ablation sites by detecting regions of abnormal electrogram activity and lesion validation subsequent to RF energy delivery. However, incomplete lesions may present interim electrical inactivity similar to effective treatment in the acute setting, despite efforts to reveal them with pacing or drugs, such as adenosine. Studies report that the misidentification and recovery of such lesions is a leading cause of arrhythmia recurrence and repeat procedures. In previous work, we demonstrated spectroscopic characterization of cardiac tissues using a fiber optic-integrated RF ablation catheter. In this work, we introduce OSAM (optical spectroscopic anatomical mapping), the application of this spectroscopic technique to obtain 2-dimensional biodistribution maps. We demonstrate its diagnostic potential as an auxiliary method for lesion validation in treated swine preparations. Endocardial lesion sets were created on fresh swine cardiac samples using a commercial RFA system. An optically-integrated catheter console fabricated in-house was used for measurement of tissue optical spectra between 600-1000nm. Three dimensional, Spatio-spectral datasets were generated by raster scanning of the optical catheter across the treated sample surface in the presence of whole blood. Tissue optical parameters were recovered at each spatial position using an inverse Monte Carlo method. OSAM biodistribution maps showed stark correspondence with gross examination of tetrazolium chloride stained tissue specimens. Specifically, we demonstrate the ability of OSAM to readily distinguish between shallow and deeper lesions, a limitation faced by current EAM techniques. These results showcase the OSAMs potential for lesion validation strategies for the treatment of cardiac arrhythmias.

The Origin, Composition and History of Comets from Spectroscopic Studies

NASA Technical Reports Server (NTRS)

Allamandola, L. J.

1997-01-01

A wealth of information essential to understanding the composition and physical structure of cometary ice and hence gain deep insight into the comet's origin and history, can be gleaned by carrying out a full range of spectroscopic studies on the returned sample. These studies ought to be among the first performed as they are generally non-destructive and will provide a broad data bank which will be crucial in planning subsequent analysis. Examples of the spectroscopic techniques along with relative sensitivities and transitions probed, are discussed. Different kind of "spectroscopy" is summarized, with emphasis placed on the kind of information each provides. Infrared spectroscopy should be the premier method of analysis as the mid-IR absorption spectrum of a substance contains more global information about the identity and structure of that material than any other property. In fact, the greatest strides in our understanding of the composition of interstellar ices (thought by many to be the primordial material from which comets have formed) have been taken during the past ten years or so because this was when high quality infrared spectra of the interstellar medium (ISM) first became available. The interpretation of the infrared spectra of mixtures, such as expected in comets, is often (not always) ambiguous. Consequently, a full range of other non-destructive, complementary spectroscopic measurements are required to fully characterize the material, to probe for substances for which the IR is not well suited and to lay the groundwork for future analysis. Given the likelihood that the icy component (including some of the organic and mineral phases) of the returned sample will be exceedingly complex, these techniques must be intensely developed over the next decade and then made ready to apply flawlessly to what will certainly be one of the most precious, and most challenging, samples ever analyzed.

Prospects for laser-induced breakdown spectroscopy for biomedical applications: a review.

PubMed

Singh, Vivek Kumar; Rai, Awadhesh Kumar

2011-09-01

We review the different spectroscopic techniques including the most recent laser-induced breakdown spectroscopy (LIBS) for the characterization of materials in any phase (solid, liquid or gas) including biological materials. A brief history of the laser and its application in bioscience is presented. The development of LIBS, its working principle and its instrumentation (different parts of the experimental set up) are briefly summarized. The generation of laser-induced plasma and detection of light emitted from this plasma are also discussed. The merit and demerits of LIBS are discussed in comparison with other conventional analytical techniques. The work done using the laser in the biomedical field is also summarized. The analysis of different tissues, mineral analysis in different organs of the human body, characterization of different types of stone formed in the human body, analysis of biological aerosols using the LIBS technique are also summarized. The unique abilities of LIBS including detection of molecular species and calibration-free LIBS are compared with those of other conventional techniques including atomic absorption spectroscopy, inductively coupled plasma atomic emission spectroscopy and mass spectroscopy, and X-ray fluorescence.

Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

PubMed Central

Wang, Chuji; Sahay, Peeyush

2009-01-01

Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC) disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS), cavity ringdown spectroscopy (CRDS), integrated cavity output spectroscopy (ICOS), cavity enhanced absorption spectroscopy (CEAS), cavity leak-out spectroscopy (CALOS), photoacoustic spectroscopy (PAS), quartz-enhanced photoacoustic spectroscopy (QEPAS), and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS). Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis. PMID:22408503

UV-fluorescence spectroscopic technique in the diagnosis of breast, ovarian, uterus, and cervix cancer

NASA Astrophysics Data System (ADS)

Das, Bidyut B.; Glassman, Wenling S.; Alfano, Robert R.; Cleary, Joseph; Prudente, R.; Celmer, Edward J.; Lubicz, Stephanie

1991-06-01

Malignant breast tumors can be separated from benign and normal tissues using uv-fluorescence spectroscopic technique. Using the same method one can also distinguish cancerous tissues from noncancerous ones in case of cervix, uterus and ovary.

Extraction, Purification, and Spectroscopic Characterization of a Mixture of Capsaicinoids

ERIC Educational Resources Information Center

Wagner, Carl E.; Cahill, Thomas M.; Marshall, Pamela A.

2011-01-01

This laboratory experiment provides a safe and effective way to instruct undergraduate organic chemistry students about natural-product extraction, purification, and NMR spectroscopic characterization. On the first day, students extract dried habanero peppers with toluene, perform a pipet silica gel column to separate carotenoids from…

Characterization of domain-specific interaction of synthesized dye with serum proteins by spectroscopic and docking approaches along with determination of in vitro cytotoxicity and antiviral activity.

PubMed

Rudra, Suparna; Dasmandal, Somnath; Patra, Chiranjit; Patel, Biman Kumar; Paul, Suvendu; Mahapatra, Ambikesh

2017-11-20

The interaction between a synthesized dye with proteins, bovine, and human serum albumin (BSA, HSA, respectively) under physiological conditions has been characterized in detail, by means of steady-state and time-resolved fluorescence, UV-vis absorption, and circular dichroism (CD) techniques. An extensive time-resolved fluorescence spectroscopic characterization of the quenching process has been undertaken in conjugation with temperature-dependent fluorescence quenching studies to divulge the actual quenching mechanism. From the thermodynamic observations, it is clear that the binding process is a spontaneous molecular interaction, in which van der Waals and hydrogen bonding interactions play the major roles. The UV-vis absorption and CD results confirm that the dye can induce conformational and micro-environmental changes of both the proteins. In addition, the dye binding provokes the functionality of the native proteins in terms of esterase-like activity. The average binding distance (r) between proteins and dye has been calculated using FRET. Cytotoxicity and antiviral effects of the dye have been found using Vero cell and HSV-1F virus by performing MTT assay. The AutoDock-based docking simulation reveals the probable binding location of dye within the sub-domain IIA of HSA and IB of BSA.

Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

NASA Astrophysics Data System (ADS)

Tamer, Ömer; Avcı, Davut; Atalay, Yusuf; Çoşut, Bünyemin; Zorlu, Yunus; Erkovan, Mustafa; Yerli, Yusuf

2016-02-01

A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pic)2(H2O)2] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (pic) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (α) and hyperpolarizability (β) parameters.

High wavenumber Raman spectroscopy in the characterization of urinary metabolites of normal subjects, oral premalignant and malignant patients

NASA Astrophysics Data System (ADS)

Brindha, Elumalai; Rajasekaran, Ramu; Aruna, Prakasarao; Koteeswaran, Dornadula; Ganesan, Singaravelu

2017-01-01

Urine has emerged as one of the diagnostically potential bio fluids, as it has many metabolites. As the concentration and the physiochemical properties of the urinary metabolites may vary under pathological transformation, Raman spectroscopic characterization of urine has been exploited as a significant tool in identifying several diseased conditions, including cancers. In the present study, an attempt was made to study the high wavenumber (HWVN) Raman spectroscopic characterization of urine samples of normal subjects, oral premalignant and malignant patients. It is concluded that the urinary metabolites flavoproteins, tryptophan and phenylalanine are responsible for the observed spectral variations between the normal and abnormal groups. Principal component analysis-based linear discriminant analysis was carried out to verify the diagnostic potentiality of the present technique. The discriminant analysis performed across normal and oral premalignant subjects classifies 95.6% of the original and 94.9% of the cross-validated grouped cases correctly. In the second analysis performed across normal and oral malignant groups, the accuracy of the original and cross-validated grouped cases was 96.4% and 92.1% respectively. Similarly, the third analysis performed across three groups, normal, oral premalignant and malignant groups, classifies 93.3% and 91.2% of the original and cross-validated grouped cases correctly.

Synthesis, spectroscopic, structural and thermal characterizations of vanadyl(IV) adenine complex prospective as antidiabetic drug agent

NASA Astrophysics Data System (ADS)

El-Megharbel, Samy M.; Hamza, Reham Z.; Refat, Moamen S.

2015-01-01

The vanadyl(IV) adenine complex; [VO(Adn)2]ṡSO4; was synthesized and characterized. The molar conductivity of this complex was measured in DMSO solution that showed an electrolyte nature. Spectroscopic investigation of the green solid complex studied here indicate that the adenine acts as a bidentate ligand, coordinated to vanadyl(IV) ions through the nitrogen atoms N7 and nitrogen atom of amino group. Thus, from the results presented the vanadyl(IV) complex has square pyramid geometry. Further characterizations using thermal analyses and scanning electron techniques was useful. The aim of this paper was to introduce a new drug model for the diabetic complications by synthesized a novel mononuclear vanadyl(IV) adenine complex to mimic insulin action and reducing blood sugar level. The antidiabetic ability of this complex was investigated in STZ-induced diabetic mice. The results suggested that VO(IV)/adenine complex has antidiabetic activity, it improved the lipid profile, it improved liver and kidney functions, also it ameliorated insulin hormone and blood glucose levels. The vanadyl(IV) complex possesses an antioxidant activity and this was clear through studying SOD, CAT, MDA, GSH and methionine synthase. The current results support the therapeutic potentiality of vanadyl(IV)/adenine complex for the management and treatment of diabetes.

Betacyanins from bracts of Bougainvillea glabra.

PubMed

Heuer, S; Richter, S; Metzger, J W; Wray, V; Nimtz, M; Strack, D

1994-10-01

Betacyanins from the bracts of Bougainvillea glabra were isolated and characterized by a combination of spectroscopic techniques (DAD-HPLC, NMR, LC-MS, GC-MS, electrospray MS, tandem MS) as gomphrenin I (betanidin 6-O-beta-glucoside) and various derivatives of bougainvillein-v (betanidin 6-O-beta-sophoroside), i.e. mono- and diglucosylsophorosides which are acylated with 4-coumaric and caffeic acid (mono- and diesters). Besides the betacyanins, B. glabra bracts accumulated large amounts of flavonols (kaempferol and quercetin conjugates) reaching ratios of flavonol to betacyanin of 1:1.

X-Ray Spectroscopic Laboratory Experiments in Support of the X-Ray Astronomy Program

NASA Technical Reports Server (NTRS)

Kahn, Steven M.

1997-01-01

Our program is to perform a series of laboratory investigations designed to resolved significant atomic physics uncertainties that limit the interpretation of cosmic X-ray spectra. Specific goals include a quantitative characterization of Fe L-shell spectra; the development of new techniques to simulate Maxwellian plasmas using an Electron Beam Ion Trap (EBIT); and the measurement of dielectronic recombination rates for photoionized gas. New atomic calculations have also been carried out in parallel with the laboratory investigations.

Preparation of antibacterial textile using laser ablation method

NASA Astrophysics Data System (ADS)

Shahidi, Sheila; Rashidian, M.; Dorranian, D.

2018-02-01

A facile in situ laser ablation synthesis of Copper nanoparticles on cotton fabric is reported in this paper. This synthetic method is a laser ablation based fabrication of Cu nanoparticles on cotton fabric for improved performance and antibacterial activity. The treated cotton fabric was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-Visible spectroscopic techniques and antibacterial counting test. Very good antibacterial behavior of treated fabrics achieved. This fabric can be used as medical and industrial textiles.

Isolated, well-defined organovanadium(iii) on silica: Single-site catalyst for hydrogenation of alkenes and alkynes

DOE PAGES

Sohn, H.; Camacho-Bunquin, J.; Langeslay, R. R.; ...

2017-05-03

Well-defined, isolated, single-site organovanadium(III) catalyst on SiO 2 [(SiO 2)V(Mes)(THF)] were synthesized via surface organometallic chemistry, and fully characterized using a combination of analytical and spectroscopic techniques (EA, ICP, 1H NMR, TGA-MS, EPR, XPS, DR-UV/Vis, UV-Raman, DRIFTS, XAS). The catalysts exhibit unprecedented reactivity in liquid- and gas-phase alkene/alkyne hydrogenation. Catalyst poisoning experiments revealed that 100% of the V sites are active for hydrogenation.

Mono-, di-, and tri- tert-butyl ethers of glycerol . A molecular spectroscopic study

NASA Astrophysics Data System (ADS)

Jamróz, Małgorzata E.; Jarosz, Małgorzata; Witowska-Jarosz, Janina; Bednarek, Elżbieta; Tęcza, Witold; Jamróz, Michał H.; Dobrowolski, Jan Cz.; Kijeński, Jacek

2007-07-01

MS, NMR, IR and Raman molecular spectroscopy techniques were applied to characterize 3- tert-butoxy-propane-1,2-diol, 1,3-di- tert-butoxy-propan-2-ol, and 1,2,3-tri- tert-butoxy-propane. These ethers are the main products of glycerol etherification reaction and are excellent oxygen additives for diesel fuel. Computational DFT/ B3LYP/6-31G ** studies were performed to support and rationalize both vibrational spectroscopy analysis and the isomer ratio.

Coherent imaging at the diffraction limit

PubMed Central

Thibault, Pierre; Guizar-Sicairos, Manuel; Menzel, Andreas

2014-01-01

X-ray ptychography, a scanning coherent diffractive imaging technique, holds promise for imaging with dose-limited resolution and sensitivity. If the foreseen increase of coherent flux by orders of magnitude can be matched by additional technological and analytical advances, ptychography may approach imaging speeds familiar from full-field methods while retaining its inherently quantitative nature and metrological versatility. Beyond promises of high throughput, spectroscopic applications in three dimensions become feasible, as do measurements of sample dynamics through time-resolved imaging or careful characterization of decoherence effects. PMID:25177990

Coherent imaging at the diffraction limit.

PubMed

Thibault, Pierre; Guizar-Sicairos, Manuel; Menzel, Andreas

2014-09-01

X-ray ptychography, a scanning coherent diffractive imaging technique, holds promise for imaging with dose-limited resolution and sensitivity. If the foreseen increase of coherent flux by orders of magnitude can be matched by additional technological and analytical advances, ptychography may approach imaging speeds familiar from full-field methods while retaining its inherently quantitative nature and metrological versatility. Beyond promises of high throughput, spectroscopic applications in three dimensions become feasible, as do measurements of sample dynamics through time-resolved imaging or careful characterization of decoherence effects.

Non-Destructive and rapid evaluation of staple foods quality by using spectroscopic techniques: A review.

PubMed

Su, Wen-Hao; He, Hong-Ju; Sun, Da-Wen

2017-03-24

Staple foods, including cereals, legumes, and root/tuber crops, dominate the daily diet of humans by providing valuable proteins, starch, oils, minerals, and vitamins. Quality evaluation of staple foods is primarily carried out on sensory (e.g. external defect, color), adulteration (e.g. species, origin), chemical (e.g. starch, proteins), mycotoxin (e.g. Fusarium toxin, aflatoxin), parasitic infection (e.g. weevil, beetle), and internal physiological (e.g. hollow heart, black heart) aspects. Conventional methods for the quality assessment of staple foods are always laborious, destructive, and time-consuming. Requirements for online monitoring of staple foods have been proposed to encourage the development of rapid, reagentless, and noninvasive techniques. Spectroscopic techniques, such as visible-infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, and spectral imaging, have been introduced as promising analytical tools and applied for the quality evaluation of staple foods. This review summarizes the recent applications and progress of such spectroscopic techniques in determining various qualities of staple foods. Besides, challenges and future trends of these spectroscopic techniques are also presented.

Insights on diagnosis of oral cavity pathologies by infrared spectroscopy: A review

NASA Astrophysics Data System (ADS)

Giorgini, Elisabetta; Balercia, Paolo; Conti, Carla; Ferraris, Paolo; Sabbatini, Simona; Rubini, Corrado; Tosi, Giorgio

2013-11-01

Fourier-Transform Infrared microspectroscopy, a largely used spectroscopic technique in basic and industrial researches, offers the possibility to analyze the vibrational features of molecular groups within a variety of environments. In the bioclinical field, and, in particular, in the study of cells, tissues and biofluids, it could be considered a supporting objective technique able to characterize the biochemical processes involved in relevant pathologies, such as tumoral diseases, highlighting specific spectral markers associable with the principal biocomponents (proteins, lipids and carbohydrates). In this article, we review the applications of infrared spectroscopy to the study of tumoral diseases of oral cavity compartments with the aim to improve understanding of biological processes involved during the onset of these lesions and to afford to an early diagnosis. Spectral studies on mouth, salivary glands and oral cystic lesions, objectively discriminate normal from dysplastic and cancer states characterizing also the grading.

Synthesis and crystal structure of an oxovanadium(IV) complex with a pyrazolone ligand and its use as a heterogeneous catalyst for the oxidation of styrene under mild conditions.

PubMed

Parihar, Sanjay; Pathan, Soyeb; Jadeja, R N; Patel, Anjali; Gupta, Vivek K

2012-01-16

1-Phenyl-3-methyl-4-touloyl-5-pyrazolone (ligand) was synthesized and used to prepare an oxovanadium(IV) complex. The complex was characterized by single-crystal X-ray analysis and various spectroscopic techniques. The single-crystal X-ray analysis of the complex shows that the ligands are coordinated in a syn configuration to each other and create a distorted octahedral environment around the metal ion. A heterogeneous catalyst comprising an oxovanadium(IV) complex and hydrous zirconia was synthesized, characterized by various physicochemical techniques, and successfully used for the solvent-free oxidation of styrene. The influence of the reaction parameters (percent loading, molar ratio of the substrate to H(2)O(2), amount of catalyst, and reaction time) was studied. The catalyst was reused three times without any significant loss in the catalytic activity.

Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

NASA Astrophysics Data System (ADS)

Roldán, Clodoaldo; Juanes, David; Ferrazza, Livio; Carballo, Jorgelina

2016-02-01

This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series "Vision of Spain" commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper-arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.

All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

PubMed Central

Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

2016-01-01

We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm). PMID:26806215

Synthesis, characterization of α-amino acid Schiff base derived Ru/Pt complexes: Induces cytotoxicity in HepG2 cell via protein binding and ROS generation

NASA Astrophysics Data System (ADS)

Alsalme, Ali; Laeeq, Sameen; Dwivedi, Sourabh; Khan, Mohd. Shahnawaz; Al Farhan, Khalid; Musarrat, Javed; Khan, Rais Ahmad

2016-06-01

We have synthesized two new complexes of platinum (1) and ruthenium (2) with α-amino acid, L-alanine, and 2,3-dihydroxybenzaldehyde derived Schiff base (L). The ligand and both complexes were characterized by using elemental analysis and several other spectroscopic techniques viz; IR, 1H, 13C NMR, EPR, and ESI-MS. Furthermore, the protein-binding ability of synthesized complexes was monitored by UV-visible, fluorescence and circular dichroism techniques with a model protein, human serum albumin (HSA). Both the PtL2 and RuL2 complexes displayed significant binding towards HSA. Also, in vitro cytotoxicity assay for both complexes was carried out on human hepatocellular carcinoma cancer (HepG2) cell line. The results showed concentration-dependent inhibition of cell viability. Moreover, the generation of reactive oxygen species was also evaluated, and results exhibited substantial role in cytotoxicity.

All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink.

PubMed

Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

2016-01-25

We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm).

Physico-chemical characterization, density functional theory (DFT) studies and Hirshfeld surface analysis of a new organic optical material: 1H-benzo[d]imidazol-3-ium-2,4,6-trinitrobenzene-1,3 bis(olate)

NASA Astrophysics Data System (ADS)

Dhamodharan, P.; Sathya, K.; Dhandapani, M.

2017-10-01

A novel organic crystal, 1H-benzo[d]imidazol-3-ium-2,4,6-trinitrobenzene-1,3 bis(olate) (BITB), was synthesized. Single crystals of BITB were harvested by solution growth-slow evaporation technique. 1H and 13C NMR spectroscopic techniques were utilized to confirm the presence of various types of carbons and protons in BITB. Single crystal XRD confirms that BITB crystallizes in monoclinic system with a space group of P21/n. The suitability of this material for optical applications was assessed by optical absorption, transmittance, reflectance and refractive index spectroscopic techniques. Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set as used for the optimization of molecular structure of BITB. Greater first order hyperpolarizability value of BITB is due to intensive hydrogen bond network in the crystal. The value is 15 times greater than that of Urea, a reference standard. Computation of frontier molecular orbitals and electrostatic potential surface helped to understand the electron density and reactive sites in BITB. The material was thermally stable up to 220 °C. Hirshfeld surface analysis was performed to quantify the covalent and non covalent interactions.

Application of spectroscopic techniques for the analysis of kidney stones: a pilot study

NASA Astrophysics Data System (ADS)

Shameem, K. M., Muhammed; Chawla, Arun; Bankapur, Aseefhali; Unnikrishnan, V. K.; Santhosh, C.

2016-03-01

Identification and characterization of kidney stone remains one of the important analytical tasks in the medical field. Kidney stone is a common health complication throughout the world, which may cause severe pain, obstruction and infection of urinary tract, and can lead to complete renal damage. It commonly occurs in both sexes regardless of age. Kidney stones have different composition, although each stones have a major single characteristic component. A complete understanding of a sample properties and their function can only be feasible by utilizing elemental and molecular information simultaneously. Two laser based analytical techniques; Laser Induced Breakdown spectroscopy (LIBS) and Raman spectroscopy have been used to study different types of kidney stones from different patients. LIBS and Raman spectroscopy are highly complementary spectroscopic techniques, which provide elemental and molecular information of a sample. Q-switched Nd:YAG laser at 355 nm laser having energy 17mJ per pulse at 10 Hz repetition rate was used for getting LIBS spectra. Raman measurements were carried out using a home assembled micro-Raman spectrometer. Using the recorded Raman spectra of kidney stones, we were able to differentiate different kinds of kidney stones. LIBS spectra of the same stones are showing the evidence of C, Ca, H, and O and also suggest the presence of certain pigments.

Identification and Spectroscopic Characterization of Nonheme Iron(III) Hypochlorite Intermediates.

PubMed

Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G; Padamati, Sandeep K; Gómez, Laura; Hage, Ronald; Costas, Miquel; Browne, Wesley R; de Visser, Sam P

2015-03-27

Fe III -hypohalite complexes have been implicated in a wide range of important enzyme-catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post-translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme Fe III -hypohalite intermediates of possible relevance to iron halogenases. We show that Fe III -OCl polypyridylamine complexes can be sufficiently stable at room temperature to be characterized by UV/Vis absorption, resonance Raman and EPR spectroscopies, and cryo-ESIMS. DFT methods rationalize the pathways to the formation of the Fe III -OCl, and ultimately Fe IV =O, species and provide indirect evidence for a short-lived Fe II -OCl intermediate. The species observed and the pathways involved offer insight into and, importantly, a spectroscopic database for the investigation of iron halogenases.

Identification and Spectroscopic Characterization of Nonheme Iron(III) Hypochlorite Intermediates**

PubMed Central

Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G; Padamati, Sandeep K; Gómez, Laura; Hage, Ronald; Costas, Miquel; Browne, Wesley R; de Visser, Sam P

2015-01-01

FeIII–hypohalite complexes have been implicated in a wide range of important enzyme-catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post-translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme FeIII–hypohalite intermediates of possible relevance to iron halogenases. We show that FeIII-OCl polypyridylamine complexes can be sufficiently stable at room temperature to be characterized by UV/Vis absorption, resonance Raman and EPR spectroscopies, and cryo-ESIMS. DFT methods rationalize the pathways to the formation of the FeIII-OCl, and ultimately FeIV=O, species and provide indirect evidence for a short-lived FeII-OCl intermediate. The species observed and the pathways involved offer insight into and, importantly, a spectroscopic database for the investigation of iron halogenases. PMID:25663379

Glow discharge sources for atomic and molecular analyses

NASA Astrophysics Data System (ADS)

Storey, Andrew Patrick

Two types of glow discharges were used and characterized for chemical analysis. The flowing atmospheric pressure afterglow (FAPA) source, based on a helium glow discharge (GD), was utilized to analyze samples with molecular mass spectrometry. A second GD, operated at reduced pressure in argon, was employed to map the elemental composition of a solid surface with novel optical detection systems, enabling new applications and perspectives for GD emission spectrometry. Like many plasma-based ambient desorption-ionization sources being used around the world, the FAPA requires a supply of helium to operate effectively. With increased pressures on global helium supply and pricing, the use of an interrupted stream of helium for analysis was explored for vapor and solid samples. In addition to the mass spectra generated by the FAPA source, schlieren imaging and infrared thermography were employed to map the behavior of the source and its surroundings under the altered conditions. Additionally, a new annular microplasma variation of the FAPA source was developed and characterized. A spectroscopic imaging system that utilized an adjustable-tilt interference filter was used to map the elemental composition of a sample surface by glow discharge emission spectroscopy. This apparatus was compared to other GD imaging techniques for mapping elemental surface composition. The wide bandpass filter resulted in significant spectral interferences that could be partially overcome with chemometric data processing. Because time-resolved GD emission spectroscopy can provide fine depth-profiling measurements, a natural extension of GD imaging would be its application to three-dimensional characterization of samples. However, the simultaneous cathodic sputtering that occur across the sample results in a sampling process that is not completely predictable. These issues are frequently encountered when laterally varied samples are explored with glow discharge imaging techniques. These insights are described with respect to their consequences for both imaging and conventional GD spectroscopic techniques.

Non-invasive continuous imaging of drug release from soy-based skin equivalent using wide-field interferometry

NASA Astrophysics Data System (ADS)

Gabai, Haniel; Baranes-Zeevi, Maya; Zilberman, Meital; Shaked, Natan T.

2013-04-01

We propose an off-axis interferometric imaging system as a simple and unique modality for continuous, non-contact and non-invasive wide-field imaging and characterization of drug release from its polymeric device used in biomedicine. In contrast to the current gold-standard methods in this field, usually based on chromatographic and spectroscopic techniques, our method requires no user intervention during the experiment, and only one test-tube is prepared. We experimentally demonstrate imaging and characterization of drug release from soy-based protein matrix, used as skin equivalent for wound dressing with controlled anesthetic, Bupivacaine drug release. Our preliminary results demonstrate the high potential of our method as a simple and low-cost modality for wide-field imaging and characterization of drug release from drug delivery devices.

Advances in mechanistic understanding of release rate control mechanisms of extended-release hydrophilic matrix tablets.

PubMed

Timmins, Peter; Desai, Divyakant; Chen, Wei; Wray, Patrick; Brown, Jonathan; Hanley, Sarah

2016-08-01

Approaches to characterizing and developing understanding around the mechanisms that control the release of drugs from hydrophilic matrix tablets are reviewed. While historical context is provided and direct physical characterization methods are described, recent advances including the role of percolation thresholds, the application on magnetic resonance and other spectroscopic imaging techniques are considered. The influence of polymer and dosage form characteristics are reviewed. The utility of mathematical modeling is described. Finally, how all the information derived from applying the developed mechanistic understanding from all of these tools can be brought together to develop a robust and reliable hydrophilic matrix extended-release tablet formulation is proposed.

Characterization of hybrid cobalt-porous silicon systems: protective effect of the Matrix in the metal oxidation

PubMed Central

2012-01-01

In the present work, the characterization of cobalt-porous silicon (Co-PSi) hybrid systems is performed by a combination of magnetic, spectroscopic, and structural techniques. The Co-PSi structures are composed by a columnar matrix of PSi with Co nanoparticles embedded inside, as determined by Transmission Electron Microscopy (TEM). The oxidation state, crystalline structure, and magnetic behavior are determined by X-Ray Absorption Spectroscopy (XAS) and Alternating Gradient Field Magnetometry (AGFM). Additionally, the Co concentration profile inside the matrix has been studied by Rutherford Backscattering Spectroscopy (RBS). It is concluded that the PSi matrix can be tailored to provide the Co nanoparticles with extra protection against oxidation. PMID:22938050

Synchronous luminescence spectroscopic characterization of blood elements of normal and patients with cervical cancer

NASA Astrophysics Data System (ADS)

Muthuvelu, K.; Shanmugam, Sivabalan; Koteeswaran, Dornadula; Srinivasan, S.; Venkatesan, P.; Aruna, Prakasarao; Ganesan, Singaravelu

2011-03-01

In this study the diagnostic potential of synchronous luminescence spectroscopy (SLS) technique for the characterization of normal and different pathological condition of cervix viz., moderately differentiated squamous cell carcinoma (MDSCC), poorly differentiated squamous cell carcinoma (PDSCC) and well differentiated squamous cell carcinoma (WDSSC). Synchronous fluorescence spectra were measured for 70 abnormal cases and 30 normal subjects. Characteristic, highly resolved peaks and significant spectral differences between normal and MDSCC, PDSCC and WDSCC cervical blood formed elements were obtained. The synchronous luminescence spectra of formed elements of normal and abnormal cervical cancer patients were subjected to statistical analysis. Synchronous luminescence spectroscopy provides 90% sensitivity and 92.6% specificity.

Synthesis, Spectral investigation (¹H, ¹³C) and Anti-microbial Screening of benzophenone imines.

PubMed

Khosa, Muhammad Kaleem; Jamal, Muhammad Asghar; Saif, Muhammad Jawad; Muneer, Majid; Rehman, Fazalur; Farman, Muhammad; Shoaib, Hafiz Muhammad; Shahid, Muhammad; Hameed, Shabnam

2015-11-01

New series of benzophenone imines with general formula Ph2-C=NR; R = Benzyl, 4-Fluorobenzyl, Naphthyl, Phenyl, 4-Nitrophenyl were synthesized by condensation of dichlorodiphenylmethane and different aromatic primary amines (1:1) Those imines were characterized by different physiochemical and spectroscopic techniques like melting point, elemental analysis, FT-IR, multinuclear NMR (¹H, ¹³C). After characterization, imines were subjected to anti-microbial activities. All compounds showed promising activity against different bacterial strains like Escherichia coli, Bacillussubtilis, Pasturellam ultocida and Staphylococcus aureus as well as fungal strains like Alternata alternaria, Ganoderma lucidium, Penicillium notatum and Trichoderma harzianum using Amoxicillin and Flucanazole as a standard drugs respectively.

SbCl3-catalyzed one-pot synthesis of 4,4′-diaminotriarylmethanes under solvent-free conditions: Synthesis, characterization, and DFT studies

PubMed Central

2011-01-01

Summary A simple, efficient, and mild procedure for a solvent-free one-step synthesis of various 4,4′-diaminotriarylmethane derivatives in the presence of antimony trichloride as catalyst is described. Triarylmethane derivatives were prepared in good to excellent yields and characterized by elemental analysis, FTIR, 1H and 13C NMR spectroscopic techniques. The structural and vibrational analysis were investigated by performing theoretical calculations at the HF and DFT levels of theory by standard 6-31G*, 6-31G*/B3LYP, and B3LYP/cc-pVDZ methods and good agreement was obtained between experimental and theoretical results. PMID:21445373

Characterization and Discrimination of Gram-Positive Bacteria Using Raman Spectroscopy with the Aid of Principal Component Analysis.

PubMed

Colniță, Alia; Dina, Nicoleta Elena; Leopold, Nicolae; Vodnar, Dan Cristian; Bogdan, Diana; Porav, Sebastian Alin; David, Leontin

2017-09-01

Raman scattering and its particular effect, surface-enhanced Raman scattering (SERS), are whole-organism fingerprinting spectroscopic techniques that gain more and more popularity in bacterial detection. In this work, two relevant Gram-positive bacteria species, Lactobacillus casei ( L. casei ) and Listeria monocytogenes ( L. monocytogenes ) were characterized based on their Raman and SERS spectral fingerprints. The SERS spectra were used to identify the biochemical structures of the bacterial cell wall. Two synthesis methods of the SERS-active nanomaterials were used and the recorded spectra were analyzed. L. casei and L. monocytogenes were successfully discriminated by applying Principal Component Analysis (PCA) to their specific spectral data.

Characterization and Discrimination of Gram-Positive Bacteria Using Raman Spectroscopy with the Aid of Principal Component Analysis

PubMed Central

Leopold, Nicolae; Vodnar, Dan Cristian; Bogdan, Diana; Porav, Sebastian Alin; David, Leontin

2017-01-01

Raman scattering and its particular effect, surface-enhanced Raman scattering (SERS), are whole-organism fingerprinting spectroscopic techniques that gain more and more popularity in bacterial detection. In this work, two relevant Gram-positive bacteria species, Lactobacillus casei (L. casei) and Listeria monocytogenes (L. monocytogenes) were characterized based on their Raman and SERS spectral fingerprints. The SERS spectra were used to identify the biochemical structures of the bacterial cell wall. Two synthesis methods of the SERS-active nanomaterials were used and the recorded spectra were analyzed. L. casei and L. monocytogenes were successfully discriminated by applying Principal Component Analysis (PCA) to their specific spectral data. PMID:28862655

TiO2 supported gold nanoparticles: An efficient photocatalyst for oxidation of alcohol to aldehyde and ketone in presence of visible light irradiation

NASA Astrophysics Data System (ADS)

Gogoi, Nibedita; Borah, Geetika; Gogoi, Pradip K.; Chetia, Tridip Ranjan

2018-01-01

An efficient heterogeneous photocatalyst composed of Au nanoparticle supported on TiO2 (anatase) is prepared by sol-gel method. This prepared nanocomposite showed good catalytic activity in the oxidation of various alcohols to aldehyde and ketone under irradiation of visible light. Various spectroscopic techniques including UV-Visible absorption spectral studies and photoluminescence study are employed to characterize the catalyst. It was also characterized by XRD, TEM, BET, XPS and ICP-AES analysis. In contrast to air and H2O2, use of TBHP as oxidant gave good yield. The reaction conditions with respect to solvent and amount of catalyst are optimized.

Material parameter estimation with terahertz time-domain spectroscopy.

PubMed

Dorney, T D; Baraniuk, R G; Mittleman, D M

2001-07-01

Imaging systems based on terahertz (THz) time-domain spectroscopy offer a range of unique modalities owing to the broad bandwidth, subpicosecond duration, and phase-sensitive detection of the THz pulses. Furthermore, the possibility exists for combining spectroscopic characterization or identification with imaging because the radiation is broadband in nature. To achieve this, we require novel methods for real-time analysis of THz waveforms. This paper describes a robust algorithm for extracting material parameters from measured THz waveforms. Our algorithm simultaneously obtains both the thickness and the complex refractive index of an unknown sample under certain conditions. In contrast, most spectroscopic transmission measurements require knowledge of the sample's thickness for an accurate determination of its optical parameters. Our approach relies on a model-based estimation, a gradient descent search, and the total variation measure. We explore the limits of this technique and compare the results with literature data for optical parameters of several different materials.

Fourier Transform Infrared (FTIR) Spectroscopy, Ultraviolet Resonance Raman (UVRR) Spectroscopy, and Atomic Force Microscopy (AFM) for Study of the Kinetics of Formation and Structural Characterization of Tau Fibrils.

PubMed

Ramachandran, Gayathri

2017-01-01

Kinetic studies of tau fibril formation in vitro most commonly employ spectroscopic probes such as thioflavinT fluorescence and laser light scattering or negative stain transmission electron microscopy. Here, I describe the use of Fourier transform infrared (FTIR) spectroscopy, ultraviolet resonance Raman (UVRR) spectroscopy, and atomic force microscopy (AFM) as complementary probes for studies of tau aggregation. The sensitivity of vibrational spectroscopic techniques (FTIR and UVRR) to secondary structure content allows for measurement of conformational changes that occur when the intrinsically disordered protein tau transforms into cross-β-core containing fibrils. AFM imaging serves as a gentle probe of structures populated over the time course of tau fibrillization. Together, these assays help further elucidate the structural and mechanistic complexity inherent in tau fibril formation.

SEM, EDX, Infrared and Raman spectroscopic characterization of the silicate mineral yuksporite

NASA Astrophysics Data System (ADS)

Frost, Ray L.; López, Andrés; Scholz, Ricardo; Theiss, Frederick L.; Romano, Antônio Wilson

2015-02-01

The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH)ṡH2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0 mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087 cm-1 and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668 cm-1. A very sharp band is observed at 3668 cm-1 and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628 cm-1 are assigned to water stretching vibrations.

Structural and spectroscopic studies of a commercial glassy carbon

NASA Astrophysics Data System (ADS)

Parker, Stewart F.; Imberti, Silvia; Callear, Samantha K.; Albers, Peter W.

2013-12-01

Glassy carbon is a form of carbon made by heating a phenolic resin to high temperature in an inert atmosphere. It has been suggested that it is composed of fullerene-like structures. The aim of the present work was to characterize the material using both structural (neutron diffraction and transmission electron microscopy) and spectroscopic (inelastic neutron scattering, Raman and X-ray photoelectron spectroscopies) methods. We find no evidence to support the suggestion of fullerene-like material being present to a significant extent, rather the model that emerges from all of the techniques is that the material is very like amorphous carbon, consisting of regions of small graphite-like basic structural units of partly stacked but mismatched structure with the edges terminated by hydrogen or hydroxyls. We do find evidence for the presence of a small quantity of water trapped in the network and suggest that this may account for batch-to-batch variation in properties that may occur.

Mono and binuclear ruthenium(II) complexes containing 5-chlorothiophene-2-carboxylic acid ligands: Spectroscopic analysis and computational studies

NASA Astrophysics Data System (ADS)

Swarnalatha, Kalaiyar; Kamalesu, Subramaniam; Subramanian, Ramasamy

2016-11-01

New Ruthenium complexes I, II and III were synthesized using 5-chlorothiophene-2-carboxylic acid (5TPC), as ligand and the complexes were characterized by elemental analysis, FT-IR, 1H, 13C NMR, and mass spectroscopic techniques. Photophysical and electrochemical studies were carried out and the structures of the synthesized complex were optimized using density functional theory (DFT). The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and Mulliken atomic charges of the molecules are determined at the B3LYP method and standard 6-311++G (d,p) basis set starting from optimized geometry. They possess excellent stabilities and their thermal decomposition temperatures are 185 °C, 180 °C and 200 °C respectively, indicating that the metal complexes are suitable for the fabrication processes of optoelectronic devices.

Synthesis and crystal structure determination of copper(II)-complex: In vitro DNA and HSA binding, pBR322 plasmid cleavage, cell imaging and cytotoxic studies.

PubMed

Tabassum, Sartaj; Zaki, Mehvash; Ahmad, Musheer; Afzal, Mohd; Srivastav, Saurabh; Srikrishna, Saripella; Arjmand, Farukh

2014-08-18

New Cu(II) complex 1 of indole-3-propionic acid and 1,10-phenanthroline was synthesized and characterized by analytical, spectroscopic and single crystal X-ray diffraction. In vitro DNA binding studies of 1 was performed by employing UV-vis and fluorescence spectroscopic techniques. The binding affinity towards human serum albumin (HSA) was also investigated to understand the carrier role in body system, as the time dependent HPLC experiment of 1 revealed that bonded drug with protein releases slowly in presence of DNA. Complex 1 exhibited good anti-tumor activity (GI50 values <10 μg/ml), and to elucidate the mechanism of tumor inhibition, topoisomerase I enzymatic activity was carried out and further validated by cell imaging studies which clearly showed its nuclear localization. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Spectroscopic studies and structure of 3-methoxy-2 -[(2,4,4,6,6-pentachloro-1,3,5,2{lambda}{sup 5},4{lambda}{sup 5},6{lambda}{sup 5}-triazatriphosphin-2-yl)oxy] benzaldehyde

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

Oezay, H.; Yildiz, M., E-mail: myildiz@comu.edu.tr; Uenver, H.

2013-01-15

The compound called 3-methoxy-2- [(2,4,4,6,6-pentachloro-1,3,5,2{lambda}{sup 5},4{lambda}{sup 5},6{lambda}{sup 5}-triazatriphosphin-2-yl)oxy] benzaldehyde has been synthesized from the reaction of 2-hydroxy-3-methoxybenzaldehyde with hexachlorocyclotriphosphazene. It has been characterized by elemental analysis, MS, IR, {sup 1}H NMR, {sup 13}C NMR, {sup 31}P NMR and UV-visible spectroscopic techniques. The structure of the title compound has been determind by X-ray analysis. Crystals are orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, Z = 4, a = 7.705(1), b = 12.624(1), c = 17.825(2) A, R{sub 1} = 0.0390 and wR{sub 2} = 0.1074 [I > 2{sigma}(I)], respectively.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer.

PubMed

Khun, Kimleang; Ibupoto, Zafar Hussain; AlSalhi, Mohamad S; Atif, Muhammad; Ansari, Anees A; Willander, Magnus

2013-09-30

In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer

PubMed Central

Khun, Kimleang; Ibupoto, Zafar Hussain; AlSalhi, Mohamad S.; Atif, Muhammad; Ansari, Anees A.; Willander, Magnus

2013-01-01

In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices. PMID:28788336

Growth, structure, Hirshfeld surface and spectroscopic properties of 2-amino-4-hydroxy-6-methylpyrimidinium-2,3-pyrazinedicorboxylate single crystal

NASA Astrophysics Data System (ADS)

Faizan, Mohd; Alam, Mohammad Jane; Afroz, Ziya; Rodrigues, Vítor Hugo Nunes; Ahmad, Shabbir

2018-03-01

The present work is focused on the crystal structure, vibrational spectroscopy and DFT calculations of hydrogen bonded 2,3-pyrazinedicorboxylic acid and 2-amino-4-hydroxy-6-methylpyrimidine (PDCA-.AHMP+) crystal. The crystal structure has been determined using single crystal X-ray diffraction analysis which shows that the crystal belongs to monoclinic space group P21/n. The PDCA-.AHMP+ crystal has been characterized by FTIR, FT-Raman and FT-NMR spectroscopic techniques. The FTIR and FT-Raman spectra of the complex have unique spectroscopic feature as compared with those of the starting material to confirm salt formation. The theoretical vibrational studies have been performed to understand the modes of the vibrations of asymmetric unit of the complex by DFT methods. Hirschfeld surface and 2D fingerprint plots analyses were carried out to investigate the intermolecular interactions and its contribution in the building of PDCA-.AHMP+ crystal. The experimental and simulated 13C and 1H NMR studies have assisted in structural analysis of PDCA-.AHMP+ crystal. The electronic spectroscopic properties of the complex were explored by the experimental as well as theoretical electronic spectra simulated using TD-DFT/IEF-PCM method at B3LYP/6-311++G (d,p) level of theory. In addition, frontier molecular orbitals, molecular electrostatic potential map (MEP) and nonlinear optical (NLO) properties using DFT method have been also presented.

ACCURATE SPECTROSCOPIC CHARACTERIZATION OF PROTONATED OXIRANE: A POTENTIAL PREBIOTIC SPECIES IN TITAN'S ATMOSPHERE.

PubMed

Puzzarini, Cristina; Ali, Ashraf; Biczysko, Malgorzata; Barone, Vincenzo

2014-09-10

An accurate spectroscopic characterization of protonated oxirane has been carried out by means of state-of-the-art computational methods and approaches. The calculated spectroscopic parameters from our recent computational investigation of oxirane together with the corresponding experimental data available were used to assess the accuracy of our predicted rotational and IR spectra of protonated oxirane. We found an accuracy of about 10 cm -1 for vibrational transitions (fundamentals as well as overtones and combination bands) and, in relative terms, of 0.1% for rotational transitions. We are therefore confident that the spectroscopic data provided herein are a valuable support for the detection of protonated oxirane not only in Titan's atmosphere but also in the interstellar medium.

Spectroscopic techniques to study the immune response in human saliva

NASA Astrophysics Data System (ADS)

Nepomnyashchaya, E.; Savchenko, E.; Velichko, E.; Bogomaz, T.; Aksenov, E.

2018-01-01

Studies of the immune response dynamics by means of spectroscopic techniques, i.e., laser correlation spectroscopy and fluorescence spectroscopy, are described. The laser correlation spectroscopy is aimed at measuring sizes of particles in biological fluids. The fluorescence spectroscopy allows studying of the conformational and other structural changings in immune complex. We have developed a new scheme of a laser correlation spectrometer and an original signal processing algorithm. We have suggested a new fluorescence detection scheme based on a prism and an integrating pin diode. The developed system based on the spectroscopic techniques allows studies of complex process in human saliva and opens some prospects for an individual treatment of immune diseases.

EBIC spectroscopy - A new approach to microscale characterization of deep levels in semi-insulating GaAs

NASA Technical Reports Server (NTRS)

Li, C.-J.; Sun, Q.; Lagowski, J.; Gatos, H. C.

1985-01-01

The microscale characterization of electronic defects in (SI) GaAs has been a challenging issue in connection with materials problems encountered in GaAs IC technology. The main obstacle which limits the applicability of high resolution electron beam methods such as Electron Beam-Induced Current (EBIC) and cathodoluminescence (CL) is the low concentration of free carriers in semiinsulating (SI) GaAs. The present paper provides a new photo-EBIC characterization approach which combines the spectroscopic advantages of optical methods with the high spatial resolution and scanning capability of EBIC. A scanning electron microscope modified for electronic characterization studies is shown schematically. The instrument can operate in the standard SEM mode, in the EBIC modes (including photo-EBIC and thermally stimulated EBIC /TS-EBIC/), and in the cathodo-luminescence (CL) and scanning modes. Attention is given to the use of CL, Photo-EBIC, and TS-EBIC techniques.

Non-Destructive Spectroscopic Techniques and Multivariate Analysis for Assessment of Fat Quality in Pork and Pork Products: A Review

PubMed Central

Kucha, Christopher T.; Liu, Li; Ngadi, Michael O.

2018-01-01

Fat is one of the most important traits determining the quality of pork. The composition of the fat greatly influences the quality of pork and its processed products, and contribute to defining the overall carcass value. However, establishing an efficient method for assessing fat quality parameters such as fatty acid composition, solid fat content, oxidative stability, iodine value, and fat color, remains a challenge that must be addressed. Conventional methods such as visual inspection, mechanical methods, and chemical methods are used off the production line, which often results in an inaccurate representation of the process because the dynamics are lost due to the time required to perform the analysis. Consequently, rapid, and non-destructive alternative methods are needed. In this paper, the traditional fat quality assessment techniques are discussed with emphasis on spectroscopic techniques as an alternative. Potential spectroscopic techniques include infrared spectroscopy, nuclear magnetic resonance and Raman spectroscopy. Hyperspectral imaging as an emerging advanced spectroscopy-based technology is introduced and discussed for the recent development of assessment for fat quality attributes. All techniques are described in terms of their operating principles and the research advances involving their application for pork fat quality parameters. Future trends for the non-destructive spectroscopic techniques are also discussed. PMID:29382092

Synthesis, spectroscopic, structural and optical studies of Ru2S3 nanoparticles prepared from single-source molecular precursors

NASA Astrophysics Data System (ADS)

Mbese, Johannes Z.; Ajibade, Peter A.

2017-09-01

Homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared and characterized by spectroscopic techniques and thermogravimetric analyses. The thermogravimetric analyses (TGA) of the ruthenium complexes showed that the complexes decompose to ruthenium(III) sulfide nanoparticles. The ruthenium(III) complexes were dispersed in oleic acid and thermolysed in hexadecylamine to prepared oleic acid/hexadecylamine capped Ru2S3 nanoparticles. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the -NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. EDS spectra revealed that the prepared nanoparticles are mainly composed of Ru and S, confirming the formation of Ru2S3 nanoparticles. Powder XRD confirms that the nanoparticles are in cubic phase. The inner morphology of nanoparticles obtained from transmission electron microscopy (TEM) showed nanoparticles with narrow particle size distributions characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot are in the range 3.44-4.18 eV.

Investigation into structure and dehydration dynamic of gallic acid monohydrate: A Raman spectroscopic study.

PubMed

Cai, Qiang; Xue, Jiadan; Wang, Qiqi; Du, Yong

2018-05-02

The dehydration process of gallic acid monohydrate was carried out by heating method and characterized using Raman spectroscopic technique. Density functional theory calculation with B3LYP function is applied to simulate optimized structures and vibrational frequencies of anhydrous gallic acid and its corresponding monohydrated form. Different vibrational modes are assigned by comparison between experimental and theoretical Raman spectra of above two polymorphs. Raman spectra show that vibrational modes of the monohydrate are distinctively different from those of anhydrous one. Meanwhile, the dynamic information about dehydration process of gallic acid monohydrate could also be observed and monitored directly with the help of Raman spectral analysis. The decay rate of the characteristic band from gallic acid monohydrate and the growth rate of anhydrous one are pretty consistent with each other. It indicates that there is no intermediate present during the dehydration process of gallic acid monohydrate. The results could offer us benchmark works for identifying both anhydrous and hydrated pharmaceutical compounds, characterizing their corresponding molecular conformation within various crystalline forms, and also providing useful information about the process of dehydration dynamic at the microscopic molecular level. Copyright © 2018 Elsevier B.V. All rights reserved.

The origin, composition and history of cometary ices from spectroscopic studies

NASA Technical Reports Server (NTRS)

Allamandola, L. J.

1989-01-01

The spectroscopic analysis of pristine cometary material provides a very important probe of the chemical identity of the material as well as of the physical and chemical conditions which prevailed during the comet's history. Concerning classical spectroscopy, the spectral regions which will most likely prove most useful are the infrared, the visible and ultraviolet. Newer spectroscopic techniques which have the potential to provide equally important information include nuclear magnetic resonance (NMR) and electron spin resonance (ESR). Each technique is summarized with emphasis placed on the kind of information which can be obtained.

In situ optical measurements for characterization of flame species and remote sensing

NASA Astrophysics Data System (ADS)

Cullum, Brian Michael

1998-12-01

The following dissertation describes the use of spectroscopic techniques for both characterization of combustion intermediates and remote chemical sensing. The primary techniques that have been used for these measurements include, laser-induced fluorescence (LIF), time resolved LIF, resonance enhanced multiphoton ionization (REMPI) and Raman spectroscopy. A simple and quantitative means of measuring the efficiency of halogenated flame retardants is described, using laser-induced fluorescence (LIF). Intensity based LIF measurements of OH radical have been used to quantitatively measure the efficacy of halogenated flame retardant/polymer plaques. Temporally resolved LIF has been used to determine the extent to which the chemical kinetic theory of flame retardation applies to the effect of these compounds on combustion. We have shown that LIF of OH radicals is a very sensitive means of measuring the efficiency of these flame retardants as well as the giving information about the nature of flame retardation. In addition, we have developed a technique for the introduction of insoluble polymer plaques into a flame for fluorescence analysis. A high power pulsed Nd:YAG laser is used to ablate the sample into the flame while a second pulse from a dye laser is used to measure the LIF of OH radicals. Spectroscopic techniques are also very useful for trace remote analysis of environmental pollutants via optical fibers. A simple fiber-optic probe suitable for remote analysis using resonance enhanced multiphoton ionization (REMPI) has been developed for this purpose and is used to determine the toluene/gasoline concentration in water samples via a headspace measurement. The limit of detection for toluene in water using this probe is 0.54 ppb (wt/wt) with a sample standard deviation of 0.02 ppb (wt/wt). Another technique that has great potential for optical sensing is fluorescence lifetime imaging. A new method for measuring fluorescence lifetime images of quickly decaying species has been developed. This method employs a high powered pulsed laser that excites the fluorescent species in a dual pulse manner, and a non-gated charge coupled device (CCD) for detection of the fluorescence. Unlike other fluorescence lifetime imaging methods, this technique has the potential of monitoring fluorescent species with picosecond lifetimes.

Computational Amide I Spectroscopy for Refinement of Disordered Peptide Ensembles: Maximum Entropy and Related Approaches

NASA Astrophysics Data System (ADS)

Reppert, Michael; Tokmakoff, Andrei

The structural characterization of intrinsically disordered peptides (IDPs) presents a challenging biophysical problem. Extreme heterogeneity and rapid conformational interconversion make traditional methods difficult to interpret. Due to its ultrafast (ps) shutter speed, Amide I vibrational spectroscopy has received considerable interest as a novel technique to probe IDP structure and dynamics. Historically, Amide I spectroscopy has been limited to delivering global secondary structural information. More recently, however, the method has been adapted to study structure at the local level through incorporation of isotope labels into the protein backbone at specific amide bonds. Thanks to the acute sensitivity of Amide I frequencies to local electrostatic interactions-particularly hydrogen bonds-spectroscopic data on isotope labeled residues directly reports on local peptide conformation. Quantitative information can be extracted using electrostatic frequency maps which translate molecular dynamics trajectories into Amide I spectra for comparison with experiment. Here we present our recent efforts in the development of a rigorous approach to incorporating Amide I spectroscopic restraints into refined molecular dynamics structural ensembles using maximum entropy and related approaches. By combining force field predictions with experimental spectroscopic data, we construct refined structural ensembles for a family of short, strongly disordered, elastin-like peptides in aqueous solution.

Spectroscopic study of honey from Apis mellifera from different regions in Mexico

NASA Astrophysics Data System (ADS)

Frausto-Reyes, C.; Casillas-Peñuelas, R.; Quintanar-Stephano, JL; Macías-López, E.; Bujdud-Pérez, JM; Medina-Ramírez, I.

2017-05-01

The objective of this study was to analyze by Raman and UV-Vis-NIR Spectroscopic techniques, Mexican honey from Apis Mellífera, using representative samples with different botanic origins (unifloral and multifloral) and diverse climates. Using Raman spectroscopy together with principal components analysis, the results obtained represent the possibility to use them for determination of floral origin of honey, independently of the region of sampling. For this, the effect of heat up the honey was analyzed in relation that it was possible to greatly reduce the fluorescence background in Raman spectra, which allowed the visualization of fructose and glucose peaks. Using UV-Vis-NIR, spectroscopy, a characteristic spectrum profile of transmittance was obtained for each honey type. In addition, to have an objective characterization of color, a CIE Yxy and CIE L*a*b* colorimetric register was realized for each honey type. Applying the principal component analysis and their correlation with chromaticity coordinates allowed classifying the honey samples in one plot as: cutoff wavelength, maximum transmittance, tones and lightness. The results show that it is possible to obtain a spectroscopic record of honeys with specific characteristics by reducing the effects of fluorescence.

Spectroscopic analysis and molecular docking of imidazole derivatives and investigation of its reactive properties by DFT and molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Thomas, Renjith; Hossain, Mossaraf; Mary, Y. Sheena; Resmi, K. S.; Armaković, Stevan; Armaković, Sanja J.; Nanda, Ashis Kumar; Ranjan, Vivek Kumar; Vijayakumar, G.; Van Alsenoy, C.

2018-04-01

Solvent-free synthesis pathway for obtaining two imidazole derivatives (2-chloro-1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole (CLMPDI) and 1-(4-bromophenyl)-2-chloro-4,5-dimethyl-1H-imidazole (BPCLDI) has been reported in this work, followed by detailed experimental and computational spectroscopic characterization and reactivity study. Spectroscopic methods encompassed IR, FT-Raman and NMR techniques, with the mutual comparison of experimentally and computationally obtained results at DFT/B3LYP level of theory. Reactivity study based on DFT calculations encompassed molecular orbitals analysis, followed by calculations of molecular electrostatic potential (MEP) and average local ionization energy (ALIE) values, Fukui functions and bond dissociation energies (BDE). Additionally, the stability of title molecules in water has been investigated via molecular dynamics (MD) simulations, while interactivity with aspulvinonedimethylallyl transferase protein has been evaluated by molecular docking procedure. CLMPDI compound showed antimicrobial activity against all four bacterial strain in both gram positive and gram negative bacteria while, BPCLDI showed only in gram positive bacteria, Staphylococcus Aureus (MTCC1144). The first order hyperpolarizability of CLMPDI and BPCLDI are 20.15 and 6.10 times that of the standard NLO material urea.

Observation of molecular level behavior in molecular electronic junction device

NASA Astrophysics Data System (ADS)

Maitani, Masato

In this dissertation, I utilize AFM based scanning probe measurement and surface enhanced Raman scattering based vibrational spectroscopic analysis to directly characterize topographic, electronic, and chemical properties of molecules confined in the local area of M3 junction to elucidate the molecular level behavior of molecular junction electronic devices. In the introduction, the characterization of molecular electronic devices with different types of metal-molecule-metal (M3) structures based upon self-assembled monolayers (SAMs) is reviewed. A background of the characterization methods I use in this dissertation, conducting probe atomic force microscopy (cp-AFM) and surface enhanced Raman spectroscopy (SERS), is provided in chapter 1. Several attempts are performed to create the ideal top metal contacts on SAMs by metal vapor phase deposition in order to prevent the metal penetration inducing critical defects of the molecular electronic devices. The scanning probe microscopy (SPM), such as cp-AFM, contact mode (c-) AFM and non-contact mode (nc-) AFM, in ultra high vacuum conditions are utilized to study the process of the metal-SAM interface construction in terms of the correlation between the morphological and electrical properties including the metal nucleation and filament generation as a function of the functionalization of long-chain alkane thiolate SAMs on Au. In chapter 2, the nascent condensation process of vapor phase Al deposition on inert and reactive SAMs are studied by SPM. The results of top deposition, penetration, and filament generation of deposited Al are discussed and compared to the results previously observed by spectroscopic measurements. Cp-AFM was shown to provide new insights into Al filament formation which has not been observed by conventional spectroscopic analysis. Additionally, the electronic characteristics of individual Al filaments are measured. Chapter 3 reveals SPM characterization of Au deposition onto --COOH terminated SAMs utilized with strong surface dipole-dipole intermolecular interaction based on hydrogen bonding and ionic bonding potentially preventing the metal penetration. The observed results are discussed with kinetic paths of metal atoms on each SAM including temporal vacancies controlled by the intermolecular interactions in SAM upon the comparison with the spectroscopic results previously reported. The results in chapter 2 and 3 strongly suggests that AFM based characterization technique is powerful tool especially for detecting molecular-size local phenomena in vapor phase metal deposition process, especially, the electric short-circuit filaments growing through SAMs, which may induce critical misinterpretation of M3 junction device properties. In Chapter 4, an altered metal deposition process on inert SAM with using a buffer layer is performed to diminish the kinetic energy of impinging metal atoms. SPM characterization reveals an abrupt metal-SAM interface without any metal penetration. Examined electric characteristics also revealed typical non-resonant tunneling characteristics of long chain alkane thiolate SAMs. In chapter 5, the buffer layer assisted growth process is used to prepare a nano particles-SAM pristine interface on SAMs to control the metal-SAM interaction in order to study the fundamental issue of chemical enhancement mechanism of SERS. Identical Au nanoparticles-SAM-Au M3 structures with different Au-SAM interactions reveal a large discrepancy of enhancement factors of ˜100 attributed to the chemical interaction. In chapter 6, Raman spectroscopy of M3 junction is applied to the characterization of molecular electronics devices. A crossed nanowire junction (X-nWJ) device is employed for in-situ electronic-spectroscopic simultaneous characterization using Raman spectroscopy. A detailed study reveals the multi-probe capability of X-nWJ for in-situ Raman and in-elastic electron tunneling spectroscopy (IETS) as vibrational spectroscopies to diagnose molecular electronic devices. In chapter 7, aniline oligomer (OAn) based redox SAMs are characterized by spectroscopic and microscopic methods under different chemical redox states by reflection absorption infrared spectroscopy (RAIRS), Raman, x-ray photoelectron spectroscopy (XPS), and AFM in order to elucidate the mechanism of electric switching molecular junctions previously reported. Obtained results are discussed in terms of the chemical and geometrical conformations of molecules in closely packed SAM domains. In chapter 8, in-situ Raman spectroscopy and cp-AFM microscopic techniques are applied to study the electric switching characteristics of X-nWJ incorporating OAn based SAM. The results of tunneling current and in-situ Raman spectroscopy are discussed with the conformational change of OAn component. The conductance switching mechanism associated with domain conformation change of OAn SAM is proposed and evaluated based on the results.

Measurements of density, temperature, and their fluctuations in turbulent supersonic flow using UV laser spectroscopy

NASA Technical Reports Server (NTRS)

Fletcher, Douglas G.; Mckenzie, R. L.

1992-01-01

Nonintrusive measurements of density, temperature, and their turbulent fluctuation levels were obtained in the boundary layer of an unseeded, Mach 2 wind tunnel flow. The spectroscopic technique that was used to make the measurements is based on the combination of laser-induced oxygen fluorescence and Raman scattering by oxygen and nitrogen from the same laser pulse. Results from this demonstration experiment are compared with previous measurements obtained in the same facility using conventional probes and an earlier spectroscopic technique. Densities and temperatures measured with the current technique agree with the previous surveys to within 3 percent and 2 percent, respectively. The fluctuation amplitudes for both variables agree with the measurements obtained using the earlier spectroscopic technique and show evidence of an unsteady, weak shock wave that perturbs the boundary layer.

Label-free characterization of degenerative changes in articular cartilage by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Oshima, Yusuke; Akehi, Mayu; Kiyomatsu, Hiroshi; Miura, Hiromasa

2017-04-01

Osteoarthritis (OA) is very common joint disease in the aging population. Main symptom of OA is accompanied by degenerative changes of articular cartilage. Raman spectroscopy is a label-free technique which enables to analyze molecular composition in degenerative cartilage. We generated an animal OA model surgically induced by knee joint instability and performed Raman spectroscopic analysis for the articular cartilage. In the result, Raman spectral data of the articular cartilage showed drastic changes in comparison between OA and control side. The relative intensity of phosphate band increases in the degenerative cartilage.

Perylene Bisimide Radicals and Biradicals: Synthesis and Molecular Properties.

PubMed

Schmidt, David; Son, Minjung; Lim, Jong Min; Lin, Mei-Jin; Krummenacher, Ivo; Braunschweig, Holger; Kim, Dongho; Würthner, Frank

2015-11-16

Unprecedented neutral perylene-3,4:9,10-tetracarboxylic acid bisimide (PBI) radicals and biradicals were synthesized by facile chemical oxidation of 4-hydroxyaryl-substituted PBIs. Subsequent characterization by optical and magnetic spectroscopic techniques, as well as quantum chemical calculations, revealed an open-shell singlet biradical ground state for the PBI biradical OS-2(..) (〈s(2)〉=1.2191) with a relatively small singlet-triplet energy gap of 0.041 eV and a large singlet biradical character of y=0.72. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pyrrole based Schiff bases as colorimetric and fluorescent chemosensors for fluoride and hydroxide anions.

PubMed

Velmathi, Sivan; Reena, Vijayaraghavan; Suganya, Sivalingam; Anandan, Sambandam

2012-01-01

An efficient colorimetric sensor with pyrrole-NH moiety as binding site and nitro group as a signaling unit has been synthesized by a one step procedure and characterized by spectroscopic techniques, which displays excellent selectivity and sensitivity for fluoride and hydroxide ions. The hydrogen bonding with these anions provides remarkable colorimetric responses. (1)H NMR and FT IR studies has been carried out to confirm the hydrogen bonding. UV-vis and fluorescence spectral changes can be exploited for real time and on site application.

Synthesis of 2,4,6-trichlorophenyl hydrazones and their inhibitory potential against glycation of protein.

PubMed

Khan, Khalid Mohammed; Shah, Zarbad; Ahmad, Viqar Uddin; Khan, Momin; Taha, Muhammad; Rahim, Fazal; Jahan, Humera; Perveen, Shahnaz; Choudhary, M Iqbal

2011-11-01

2,4,6-Trichlorophenyl hydrazones 1-35 were synthesized and their in vitro antiglycation potential was evaluated. Compounds 14 (IC50 = 27.2 ± 0.00 μM), and 18 (IC50 = 55.7 ± 0.00 μM) showed an excellent activity against glycation of protein, better than the standard (rutin, IC50 = 70 ± 0.50 μM). This study thus identified a novel series of antiglycation agents. A structure-activity relationship has been studied, and all the compounds were characterized by spectroscopic techniques.

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.

Synthesis, characterization and investigation of electrochemical and spectroelectrochemical properties of peripherally tetra 4-phenylthiazole-2-thiol substituted metal-free, zinc(II), copper(II) and cobalt(II) phthalocyanines

NASA Astrophysics Data System (ADS)

Demirbaş, Ümit; Akçay, Hakkı Türker; Koca, Atıf; Kantekin, Halit

2017-08-01

In this study novel peripherally tetra 4-phenylthiazole-2-thiol substituted metal-free phthalocyanine (4) and its zinc(II) (5), copper(II) (6) and cobalt(II) (7) derivatives were synthesized and characterized by a combination of various spectroscopic techniques such as FT-IR, 1H-NMR, UV-vis and MALDI-TOF mass. Electrochemical characterizations of metallo-phthalocyanine complexes were conducted by voltammetric and in situ spectroelectrochemical measurements. CoIIPc went [CoIIPc-2]/[CoIPc-2]1-, [CoIPc-2]1-/[CoIPc-3]2-, [CoIPc-3]2-/[CoIPc-4]3- and [CoIIPc-2]/[CoIIPc-2]1+ reduction and oxidation processes respectively. Differently ZnIIPc only showed four ligand-based reductions and two ligand based oxidation processes.

Review of NMR characterization of pyrolysis oils

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

Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun

Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

Review of NMR characterization of pyrolysis oils

DOE PAGES

Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun; ...

2016-08-24

Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

Recovering the colour-dependent albedo of exoplanets with high-resolution spectroscopy: from ESPRESSO to the ELT.

NASA Astrophysics Data System (ADS)

Martins, J. H. C.; Figueira, P.; Santos, N. C.; Melo, C.; Garcia Muñoz, A.; Faria, J.; Pepe, F.; Lovis, C.

2018-05-01

The characterization of planetary atmospheres is a daunting task, pushing current observing facilities to their limits. The next generation of high-resolution spectrographs mounted on large telescopes - such as ESPRESSO@VLT and HIRES@ELT - will allow us to probe and characterize exoplanetary atmospheres in greater detail than possible to this point. We present a method that permits the recovery of the colour-dependent reflectivity of exoplanets from high-resolution spectroscopic observations. Determining the wavelength-dependent albedo will provide insight into the chemical properties and weather of the exoplanet atmospheres. For this work, we simulated ESPRESSO@VLT and HIRES@ELT high-resolution observations of known planetary systems with several albedo configurations. We demonstrate how the cross correlation technique applied to theses simulated observations can be used to successfully recover the geometric albedo of exoplanets over a range of wavelengths. In all cases, we were able to recover the wavelength dependent albedo of the simulated exoplanets and distinguish between several atmospheric models representing different atmospheric configurations. In brief, we demonstrate that the cross correlation technique allows for the recovery of exoplanetary albedo functions from optical observations with the next generation of high-resolution spectrographs that will be mounted on large telescopes with reasonable exposure times. Its recovery will permit the characterization of exoplanetary atmospheres in terms of composition and dynamics and consolidates the cross correlation technique as a powerful tool for exoplanet characterization.

Spectroscopic determination of anthraquinone in kraft pulping liquors using a membrane interface

Treesearch

X.S. Chai; X.T. Yang; Q.X. Hou; J.Y. Zhu; L.-G. Danielsson

2003-01-01

A spectroscopic technique for determining AQ in pulping liquor was developed to effectively separate AQ from dissolved lignin. This technique is based on a flow analysis system with a Nafion membrane interface. The AQ passed through the membrane is converted into its reduced form, AHQ, using sodium hydrosulfite. AHQ has distinguished absorption characteristics in the...

Synthesis of gold nanochains via photoactivation technique and their catalytic applications.

PubMed

Sinha, Arun Kumar; Basu, Mrinmoyee; Sarkar, Sougata; Pradhan, Mukul; Pal, Tarasankar

2013-05-15

The article reports a simple photoactivation technique for the synthesis of chain like assembly of spherical Au nanocrystals using a nontoxic biochemical, β-cyclodextrin under ~365 nm UV-light irradiation. Under UV irradiation, β-cyclodextrin acts as a reducing as well as capping agent and eventually becomes a stabilizing linker for Au nanoparticles. The UV-visible spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopic techniques are employed to systematically characterize the Au nanochains. Additionally, it is shown that the Au nanocrystals act as an effective catalyst for the reduction in nitrobenzene to aniline and methylene blue to leuco methylene blue in presence of suitable reducing agent. The catalytic reduction reactions and kinetic parameters are evaluated from UV-visible spectroscopy. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluating polymeric biomaterial–environment interfaces by Langmuir monolayer techniques

PubMed Central

Schöne, Anne-Christin; Roch, Toralf; Schulz, Burkhard

2017-01-01

Polymeric biomaterials are of specific relevance in medical and pharmaceutical applications due to their wide range of tailorable properties and functionalities. The knowledge about interactions of biomaterials with their biological environment is of crucial importance for developing highly sophisticated medical devices. To achieve optimal in vivo performance, a description at the molecular level is required to gain better understanding about the surface of synthetic materials for tailoring their properties. This is still challenging and requires the comprehensive characterization of morphological structures, polymer chain arrangements and degradation behaviour. The review discusses selected aspects for evaluating polymeric biomaterial–environment interfaces by Langmuir monolayer methods as powerful techniques for studying interfacial properties, such as morphological and degradation processes. The combination of spectroscopic, microscopic and scattering methods with the Langmuir techniques adapted to polymers can substantially improve the understanding of their in vivo behaviour. PMID:28468918

Spectroscopic properties for identifying sapphire samples from Ban Bo Kaew, Phrae Province, Thailand

NASA Astrophysics Data System (ADS)

Mogmued, J.; Monarumit, N.; Won-in, K.; Satitkune, S.

2017-09-01

Gemstone commercial is a high revenue for Thailand especially ruby and sapphire. Moreover, Phrae is a potential gem field located in the northern part of Thailand. The studies of spectroscopic properties are mainly to identify gemstone using advanced techniques (e.g. UV-Vis-NIR spectrophotometry, FTIR spectrometry and Raman spectroscopy). Typically, UV-Vis-NIR spectrophotometry is a technique to study the cause of color in gemstones. FTIR spectrometry is a technique to study the functional groups in gem-materials. Raman pattern can be applied to identify the mineral inclusions in gemstones. In this study, the natural sapphires from Ban Bo Kaew were divided into two groups based on colors including blue and green. The samples were analyzed by UV-Vis-NIR spectrophotometer, FTIR spectrometer and Raman spectroscope for studying spectroscopic properties. According to UV-Vis-NIR spectra, the blue sapphires show higher Fe3+/Ti4+ and Fe2+/Fe3+ absorption peaks than those of green sapphires. Otherwise, green sapphires display higher Fe3+/Fe3+ absorption peaks than blue sapphires. The FTIR spectra of both blue and green sapphire samples show the absorption peaks of -OH,-CH and CO2. The mineral inclusions such as ferrocolumbite and rutile in sapphires from this area were observed by Raman spectroscope. The spectroscopic properties of sapphire samples from Ban Bo Kaew, Phrae Province, Thailand are applied to be the specific evidence for gemstone identification.

Synthesis and characterization of poly (benzyl trimethyl ammonium chloride) ionic polymer

NASA Astrophysics Data System (ADS)

Mathew, Manjusha Elizabeth; Ahmad, Ishak; Thomas, Sabu; Daik, Rusli; Kassim, Muhammad

2018-04-01

Poly vinyl benzyl chloride (PVBC) was synthesized by free radical polymerization of 4-vinyl benzyl chloride (VBC) using benzoyl peroxide initiator at 80°C. Amine functionalised polymer prepared by treatment of PVBC with trimethyl amine in different solvents such as water, ethanol, tetra hydro furan(THF) and dimethyl formamide(DMF). The polymers characterized structurally by nuclear magnetic resonance and infrared spectroscopic techniques. The thermal decomposition of the polymer is studied by Thermo Gravimetric Analysis(TGA) and found that the polymer has stability up to 230°C. The nitrogen content of the aminated polymer determined by elemental analysis. The nitrogen content obtained from tetra hydro furan and dimethyl formamide solvents are 20.1% and 19.9% respectively.

Physico-Chemical Dynamics of Nanoparticle Formation during Laser Decontamination

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

Cheng, M.D.

2005-06-01

Laser-ablation based decontamination is a new and effective approach for simultaneous removal and characterization of contaminants from surfaces (e.g., building interior and exterior walls, ground floors, etc.). The scientific objectives of this research are to: (1) characterize particulate matter generated during the laser-ablation based decontamination, (2) develop a technique for simultaneous cleaning and spectroscopic verification, and (3) develop an empirical model for predicting particle generation for the size range from 10 nm to tens of micrometers. This research project provides fundamental data obtained through a systematic study on the particle generation mechanism, and also provides a working model for predictionmore » of particle generation such that an effective operational strategy can be devised to facilitate worker protection.« less

Spectroscopic characterization of cell membranes and their constituents of the plant-associated soil bacterium Azospirillum brasilense

NASA Astrophysics Data System (ADS)

Kamnev, A. A.; Antonyuk, L. P.; Matora, L. Yu.; Serebrennikova, O. B.; Sumaroka, M. V.; Colina, M.; Renou-Gonnord, M.-F.; Ignatov, V. V.

1999-05-01

Structural and compositional features of bacterial membranes and some of their isolated constituents (cell surface lipopolysaccharide, phospholipids) of the plant-growth-promoting diazotrophic rhizobacterium Azospirillum brasilense (wild-type strain Sp245) were characterized using Fourier transform infrared (FTIR) spectroscopy and some other techniques. FTIR spectra of the cell membranes were shown to comprise the main vibration modes of the relevant lipopolysaccharide and protein components which are believed to be involved in associative plant-bacterium interactions, as well as of phospholipid constituents. The role and functions of metal cations in the structural organization and physicochemical properties of bacterial cell membranes are also discussed considering their accumulation in the membranes from the culture medium.

Cluster Tool for In Situ Processing and Comprehensive Characterization of Thin Films at High Temperatures.

PubMed

Wenisch, Robert; Lungwitz, Frank; Hanf, Daniel; Heller, René; Zscharschuch, Jens; Hübner, René; von Borany, Johannes; Abrasonis, Gintautas; Gemming, Sibylle; Escobar-Galindo, Ramon; Krause, Matthias

2018-06-13

A new cluster tool for in situ real-time processing and depth-resolved compositional, structural and optical characterization of thin films at temperatures from -100 to 800 °C is described. The implemented techniques comprise magnetron sputtering, ion irradiation, Rutherford backscattering spectrometry, Raman spectroscopy, and spectroscopic ellipsometry. The capability of the cluster tool is demonstrated for a layer stack MgO/amorphous Si (∼60 nm)/Ag (∼30 nm), deposited at room temperature and crystallized with partial layer exchange by heating up to 650 °C. Its initial and final composition, stacking order, and structure were monitored in situ in real time and a reaction progress was defined as a function of time and temperature.

Spectroscopic and Kinetic Characterization of Peroxidase-Like π-Cation Radical Pinch-Porphyrin-Iron(III) Reaction Intermediate Models of Peroxidase Enzymes.

PubMed

Hernández Anzaldo, Samuel; Arroyo Abad, Uriel; León García, Armando; Ramírez Rosales, Daniel; Zamorano Ulloa, Rafael; Reyes Ortega, Yasmi

2016-06-27

The spectroscopic and kinetic characterization of two intermediates from the H₂O₂ oxidation of three dimethyl ester [(proto), (meso), (deuteroporphyrinato) (picdien)]Fe(III) complexes ([FePPPic], [FeMPPic] and [FeDPPic], respectively) pinch-porphyrin peroxidase enzyme models, with s = 5/2 and 3/2 Fe(III) quantum mixed spin (qms) ground states is described herein. The kinetic study by UV/Vis at λmax = 465 nm showed two different types of kinetics during the oxidation process in the guaiacol test for peroxidases (1-3 + guaiacol + H₂O₂ → oxidation guaiacol products). The first intermediate was observed during the first 24 s of the reaction. When the reaction conditions were changed to higher concentration of pinch-porphyrins and hydrogen peroxide only one type of kinetics was observed. Next, the reaction was performed only between pinch-porphyrins-Fe(III) and H₂O₂, resulting in only two types of kinetics that were developed during the first 0-4 s. After this time a self-oxidation process was observed. Our hypotheses state that the formation of the π-cation radicals, reaction intermediates of the pinch-porphyrin-Fe(III) family with the ligand picdien [N,N'-bis-pyridin-2-ylmethyl-propane-1,3-diamine], occurred with unique kinetics that are different from the overall process and was involved in the oxidation pathway. UV-Vis, ¹H-NMR and ESR spectra confirmed the formation of such intermediates. The results in this paper highlight the link between different spectroscopic techniques that positively depict the kinetic traits of artificial compounds with enzyme-like activity.

Use of different spectroscopic techniques in the analysis of Roman age wall paintings.

PubMed

Agnoli, Francesca; Calliari, Irene; Mazzocchin, Gian-Antonio

2007-01-01

In this paper the analysis of samples of Roman age wall paintings coming from: Pordenone, Vicenza and Verona is carried out by using three different techniques: energy dispersive x-rays spectroscopy (EDS), x-rays fluorescence (XRF) and proton induced x-rays emission (PIXE). The features of the three spectroscopic techniques in the analysis of samples of archaeological interest are discussed. The studied pigments were: cinnabar, yellow ochre, green earth, Egyptian blue and carbon black.

Continuous statistical modelling for rapid detection of adulteration of extra virgin olive oil using mid infrared and Raman spectroscopic data.

PubMed

Georgouli, Konstantia; Martinez Del Rincon, Jesus; Koidis, Anastasios

2017-02-15

The main objective of this work was to develop a novel dimensionality reduction technique as a part of an integrated pattern recognition solution capable of identifying adulterants such as hazelnut oil in extra virgin olive oil at low percentages based on spectroscopic chemical fingerprints. A novel Continuous Locality Preserving Projections (CLPP) technique is proposed which allows the modelling of the continuous nature of the produced in-house admixtures as data series instead of discrete points. The maintenance of the continuous structure of the data manifold enables the better visualisation of this examined classification problem and facilitates the more accurate utilisation of the manifold for detecting the adulterants. The performance of the proposed technique is validated with two different spectroscopic techniques (Raman and Fourier transform infrared, FT-IR). In all cases studied, CLPP accompanied by k-Nearest Neighbors (kNN) algorithm was found to outperform any other state-of-the-art pattern recognition techniques. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of volumetric concentration of MWCNTs on the stability and thermal conductivity of nanofluids

NASA Astrophysics Data System (ADS)

Rehman, Wajid Ur; Bhat, A. H.; Suliamon, A. A.; Khan, Ihsan Ullah; Ullah, Hafeez

2016-11-01

Environmental concerns and running down of the fossil fuel deposits which are generally being used as base oil in Drilling Fluid/Mud have attended worldwide attention and thereby, researchers have focused on using environmentally friendly drilling fluids. This study demonstrates the preparation of drilling fluids and to explore the effect of increase in the volumetric concentration of nanoparticles on the stability and thermal conductivity of nanofluids. In this research, for the formation of nanofluids, Jatropha Seed Oil was used as the base oil with the addition of multi-walled carbon nanotubes as the nanoparticles using sonication technique. The raw multi-walled carbon nanotubes were characterized by using SEM for morphological examination. The prepared drilling fluid were characterized by using UV-Visible spectroscopic technique for analyzing the stability. Thermal Conductivity measurements were also carried out for heat transfer efficiency. It was observed that the heat transfer capability of the nanofluid ameliorates with the increase in the loading percentage of multi-walled carbon nanotubes.

Optical characterization of Chinese hybrid rice using laser-induced fluorescence techniques-laboratory and remote-sensing measurements.

PubMed

Duan, Zheng; Peng, Ting; Zhu, Shiming; Lian, Ming; Li, Yiyun; Wei, Fu; Xiong, Jiabao; Svanberg, Sune; Zhao, Quanzhi; Hu, Jiandong; Zhao, Guangyu

2018-05-01

Chinese hybrid rice of different varieties, growing in paddies in the Pingqiao district, north of Xinyang city, Henan province, China, was studied in detailed spectroscopic characteristics using laser-induced fluorescence. The base for the studies was the new South China Normal University mobile lidar laboratory, which was dispatched on site, providing facilities both for laboratory studies using a 405 nm excitation source as well as remote sensing measurements at ranges from around 40 m-120 m, mostly employing the 532 nm output from a Nd:YAG laser. We, in particular, studied the spectral influence of the species varieties as well as the level of nitrogen fertilization supplied. Specially developed contrast functions as well as multivariate techniques with principal components and Fisher's discriminate analyses were applied, and useful characterization of the rice could be achieved. The chlorophyll content mapping of the 30 zones was obtained with the remote sensing measurements.

An empirical evaluation of three vibrational spectroscopic methods for detection of aflatoxins in maize.

PubMed

Lee, Kyung-Min; Davis, Jessica; Herrman, Timothy J; Murray, Seth C; Deng, Youjun

2015-04-15

Three commercially available vibrational spectroscopic techniques, including Raman, Fourier transform near infrared reflectance (FT-NIR), and Fourier transform infrared (FTIR) were evaluated to help users determine the spectroscopic method best suitable for aflatoxin analysis in maize (Zea mays L.) grain based on their relative efficiency and predictive ability. Spectral differences of Raman and FTIR spectra were more marked and pronounced among aflatoxin contamination groups than those of FT-NIR spectra. From the observations and findings in our current and previous studies, Raman and FTIR spectroscopic methods are superior to FT-NIR method in terms of predictive power and model performance for aflatoxin analysis and they are equally effective and accurate in predicting aflatoxin concentration in maize. The present study is considered as the first attempt to assess how spectroscopic techniques with different physical processes can influence and improve accuracy and reliability for rapid screening of aflatoxin contaminated maize samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation and surface characterization of plasma-treated and biomolecular-micropatterned polymer substrates

NASA Astrophysics Data System (ADS)

Langowski, Bryan Alfred

A micropatterning process creates distinct microscale domains on substrate surfaces that differ from the surfaces' original chemical/physical properties. Numerous micropatterning methods exist, each having relative advantages and disadvantages in terms of cost, ease, reproducibility, and versatility. Polymeric surfaces micropatterned with biomolecules have many applications, but are specifically utilized in tissue engineering as cell scaffolds that attempt to controlled tissue generation in vivo and ex vivo. As the physical and chemical cues presented by micropatterned substrates control resulting cellular behavior, characterization of these cues via surface-sensitive analytical techniques is essential in developing cell scaffolds that mimic complex in vivo physicochemical environments. The initial focus of this thesis is the chemical and physical characterization of plasma-treated, microcontact-printed (muCP) polymeric substrates used to direct nerve cell behavior. Unmodified and oxygen plasma-treated poly(methyl methacrylate) (PMMA) substrates were analyzed by surface sensitive techniques to monitor plasma-induced chemical and physical modifications. Additionally, protein-micropattern homogeneity and size were microscopically evaluated. Lastly, poly(dimethylsiloxane) (PDMS) stamps and contaminated PMMA substrates were characterized by spectroscopic and microscopic methods to identify a contamination source during microcontact printing. The final focus of this thesis is the development of microscale plasma-initiated patterning (muPIP) as a versatile, reproducible micropatterning method. Using muPIP, polymeric substrates were micropatterned with several biologically relevant inks. Polymeric substrates were characterized following muPIP by surface-sensitive techniques to identify the technique's underlying physical and chemical bases. In addition, neural stem cell response to muPIP-generated laminin micropatterns was microscopically and biologically evaluated. Finally, enhanced versatility of muPIP in generating microscale poly-L-lysine gradients was demonstrated.

Evaluation of the laser-induced breakdown spectroscopy technique for determination of the chemical composition of copper concentrates

NASA Astrophysics Data System (ADS)

Łazarek, Łukasz; Antończak, Arkadiusz J.; Wójcik, Michał R.; Drzymała, Jan; Abramski, Krzysztof M.

2014-07-01

Laser-induced breakdown spectroscopy (LIBS), like many other spectroscopic techniques, is a comparative method. Typically, in qualitative analysis, synthetic certified standard with a well-known elemental composition is used to calibrate the system. Nevertheless, in all laser-induced techniques, such calibration can affect the accuracy through differences in the overall composition of the chosen standard. There are also some intermediate factors, which can cause imprecision in measurements, such as optical absorption, surface structure and thermal conductivity. In this work the calibration performed for the LIBS technique utilizes pellets made directly from the tested materials (old well-characterized samples). This choice produces a considerable improvement in the accuracy of the method. This technique was adopted for the determination of trace elements in industrial copper concentrates, standardized by conventional atomic absorption spectroscopy with a flame atomizer. A series of copper flotation concentrate samples was analyzed for three elements: silver, cobalt and vanadium. We also proposed a method of post-processing the measurement data to minimize matrix effects and permit reliable analysis. It has been shown that the described technique can be used in qualitative and quantitative analyses of complex inorganic materials, such as copper flotation concentrates. It was noted that the final validation of such methodology is limited mainly by the accuracy of the characterization of the standards.

Characterization, thermal stability studies, and analytical method development of Paromomycin for formulation development.

PubMed

Khan, Wahid; Kumar, Neeraj

2011-06-01

Paromomycin (PM) is an aminoglycoside antibiotic, first isolated in the 1950s, and approved in 2006 for treatment of visceral leishmaniasis. Although isolated six decades back, sufficient information essential for development of pharmaceutical formulation is not available for PM. The purpose of this paper was to determine thermal stability and development of new analytical method for formulation development of PM. PM was characterized by thermoanalytical (DSC, TGA, and HSM) and by spectroscopic (FTIR) techniques and these techniques were used to establish thermal stability of PM after heating PM at 100, 110, 120, and 130 °C for 24 h. Biological activity of these heated samples was also determined by microbiological assay. Subsequently, a simple, rapid and sensitive RP-HPLC method for quantitative determination of PM was developed using pre-column derivatization with 9-fluorenylmethyl chloroformate. The developed method was applied to estimate PM quantitatively in two parenteral dosage forms. PM was successfully characterized by various stated techniques. These techniques indicated stability of PM for heating up to 120 °C for 24 h, but when heated at 130 °C, PM is liable to degradation. This degradation is also observed in microbiological assay where PM lost ∼30% of its biological activity when heated at 130 °C for 24 h. New analytical method was developed for PM in the concentration range of 25-200 ng/ml with intra-day and inter-day variability of < 2%RSD. Characterization techniques were established and stability of PM was determined successfully. Developed analytical method was found sensitive, accurate, and precise for quantification of PM. Copyright © 2010 John Wiley & Sons, Ltd. Copyright © 2010 John Wiley & Sons, Ltd.

Infrared Spectroscopic Imaging of Latent Fingerprints and Associated Forensic Evidence

PubMed Central

Chen, Tsoching; Schultz, Zachary D.; Levin, Ira W.

2011-01-01

Fingerprints reflecting a specific chemical history, such as exposure to explosives, are clearly distinguished from overlapping, and interfering latent fingerprints using infrared spectroscopic imaging techniques and multivariate analysis. PMID:19684917

Characterization of newly synthesized pyrimidine derivatives for corrosion inhibition as inferred from computational chemical analysis

NASA Astrophysics Data System (ADS)

El-Taib Heakal, F.; Rizk, S. A.; Elkholy, A. E.

2018-01-01

Corrosion of metallic constructions is a serious problem in most industries worldwide that can be controlled via addition of special chemicals having adsorption capability on metal surfaces and hence isolating it from the aggressive environment. These chemicals are characterized by being rich in functional groups containing free lone pairs of electrons and/or π-electrons. In the present study four newly imidazole-pyrimidine based ionic derivatives have been synthesized and their structures were characterized by means of elemental analysis and different spectroscopic techniques. Quantum chemical calculations were carried out to give insights into the structural and electronic characteristics of these fabricated compounds. Monte Carlo simulation was also applied to shed the light on our prepared corrosion inhibitor molecules by examining their aptitude to adsorb on iron surface. Our ultimate goal is to help industries in fighting corrosion by providing them with a cheap and efficient anti-corrosion molecules.

Preparation, characterization, and in vitro anti-inflammatory evaluation of novel water soluble kamebakaurin/hydroxypropyl-β-cyclodextrin inclusion complex

NASA Astrophysics Data System (ADS)

Raza, Aun; Sun, Huifang; Bano, Shumaila; Zhao, Yingying; Xu, Xiuquan; Tang, Jian

2017-02-01

To enhance the aqueous solubility of kamebakaurin (KA), it was complexed with hydroxypropyl-β-cyclodextrin (HP-β-CD). In this study, the interaction KA with HP-β-CD and their inclusion complex behavior were determined by different characterization techniques such as UV-vis, 1H NMR, FT-IR, PXRD and SEM. All the characterization information proved the development of inclusion complex KA/HP-β-CD, and this inclusion complex demonstrated discriminable spectroscopic characteristics and properties from free compound KA. The results demonstrated that the water solubility of KA was remarkably increased in the presence of HP-β-CD. Furthermore, in vitro anti-inflammatory study showed that inclusion complex KA/HP-β-CD maintained the anti-inflammatory effect of KA. These results demonstrate that HP-β-CD will be promisingly employed in the application of water-insoluble anti-inflammatory phytochemicals such as KA.

uleSIMS characterization of silver reference surfaces

NASA Astrophysics Data System (ADS)

Palitsin, V. V.; Dowsett, M. G.; Mata, B. Guzmán de la; Oloff, I. W.; Gibbons, R.

2006-07-01

Ultra low energy SIMS (uleSIMS) is a high sensitivity analytical technique that is normally used for ultra shallow profiling at a depth resolution of up to1 nm. This work describes the use of uleSIMS as both a spectroscopic and depth-profiling tool for the characterization of the early stages of corrosion formed on reference surfaces of silver. These samples are being developed to help with the characterization of tarnished surfaces in a cultural heritage context, and uleSIMS enables the tarnishing to be studied from its very earliest stages due to its high sensitivity (ppm-ppb) and surface specificity. We show that, uleSIMS can be used effectively to study the surface chemistry and aid the development of reference surfaces themselves. In particular, handling contaminants, surface dust, and residues from polishing are relatively easy to identify allowing them to be separated from the parts of the mass spectrum specific to the early stages of corrosion.

Melanin from the Nitrogen-Fixing Bacterium Azotobacter chroococcum: A Spectroscopic Characterization

PubMed Central

Banerjee, Raja

2014-01-01

Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state 13C NMR), we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation. PMID:24416247

β-SiH-containing tris(silazido) rare-earth complexes as homogeneous and grafted single-site catalyst precursors for hydroamination

DOE PAGES

Eedugurala, Naresh; Wang, Zhuoran; Yan, KaKing; ...

2017-01-25

A series of homoleptic rare-earth silazido compounds and their silica-grafted derivatives were prepared to compare spectroscopic and catalytic features under homogeneous and interfacial conditions. Trivalent tris(silazido) compounds Ln{N(SiHMe 2) tBu} 3 (Ln = Sc (1), Y (2), Lu (3)) are prepared in high yield by salt metathesis reactions. Solution-phase and solid-state characterization of 1–3 by NMR and IR spectroscopy and X-ray diffraction reveals Ln←H–Si interactions. These features are retained in solvent-coordinated 2·Et 2O, 2·THF, and 3·THF. The change in spectroscopic features characterizing the secondary interactions (ν SiH, 1 J SiH) from the unactivated SiH in the silazane HN(SiHMe 2) tBumore » follows the trend 3 > 2 > 1 ≈ 2·Et 2O > 2·THF ≈ 3·THF. Ligand lability follows the same pattern, with Et 2O readily dissociating from 2·Et 2O while THF is displaced only during surface grafting reactions. 1 and 2·THF graft onto mesoporous silica nanoparticles (MSN) to give Ln{N(SiHMe 2) tBu} n@MSN (Ln = Sc (1@MSN), Y (2@MSN)) along with THF and protonated silazido as HN(SiHMe 2) tBu and H 2N tBu. The surface species are characterized by multinuclear and multidimensional solid-state (SS) NMR spectroscopic techniques, as well as diffuse reflectance FTIR, elemental analysis, and reaction stoichiometry. A key 1 J SiH SSNMR measurement reveals that the grafted sites most closely resemble Ln·THF adducts, suggesting that siloxane coordination occurs in grafted compounds. These species catalyze the hydroamination/bicyclization of aminodialkenes, and both solution-phase and interfacial conditions provide the bicyclized product with equivalent cis:trans ratios. As a result, similar diastereoselectivities mediated by catalytic sites under the two conditions suggest similar effective environments.« less

Applications of QCL mid-IR imaging to the advancement of pathology

NASA Astrophysics Data System (ADS)

Sreedhar, Hari; Varma, Vishal K.; Bird, Benjamin; Guzman, Grace; Walsh, Michael J.

2017-03-01

Quantum Cascade Laser (QCL) spectroscopic imaging is a novel technique with many potential applications to histopathology. Like traditional Fourier Transform Infrared (FT-IR) imaging, QCL spectroscopic imaging derives biochemical data coupled to the spatial information of a tissue sample, and can be used to improve the diagnostic and prognostic value of assessment of a tissue biopsy. This technique also offers advantages over traditional FT-IR imaging, specifically the capacity for discrete frequency and real-time imaging. In this work we present applications of QCL spectroscopic imaging to tissue samples, including discrete frequency imaging, to compare with FT-IR and its potential value to pathology.

Ultrafast current imaging by Bayesian inversion

DOE Data Explorer

Somnath, Suhas; Law, Kody J. H.; Morozovska, Anna; Maksymovych, Petro; Kim, Yunseok; Lu, Xiaoli; Alexe, Marin; Archibald, Richard K; Kalinin, Sergei V; Jesse, Stephen; Vasudevan, Rama K

2016-01-01

Spectroscopic measurements of current-voltage curves in scanning probe microscopy is the earliest and one of the most common methods for characterizing local energy-dependent electronic properties, providing insight into superconductive, semiconductor, and memristive behaviors. However, the quasistatic nature of these measurements renders them extremely slow. Here, we demonstrate a fundamentally new approach for dynamic spectroscopic current imaging via full information capture and Bayesian inference analysis. This "general-mode I-V"method allows three orders of magnitude faster rates than presently possible. The technique is demonstrated by acquiring I-V curves in ferroelectric nanocapacitors, yielding >100,000 I-V curves in <20 minutes. This allows detection of switching currents in the nanoscale capacitors, as well as determination of dielectric constant. These experiments show the potential for the use of full information capture and Bayesian inference towards extracting physics from rapid I-V measurements, and can be used for transport measurements in both atomic force and scanning tunneling microscopy. The data was analyzed using pycroscopy - an open-source python package available at https://github.com/pycroscopy/pycroscopy

Spectroscopic evidence for gas-phase formation of successive beta-turns in a three-residue peptide chain.

PubMed

Chin, Wutharath; Compagnon, Isabelle; Dognon, Jean-Pierre; Canuel, Clélia; Piuzzi, François; Dimicoli, Iliana; von Helden, Gert; Meijer, Gerard; Mons, Michel

2005-02-09

We report the first gas-phase spectroscopic study of a three-residue model of a peptide chain, Ac-Phe-Gly-Gly-NH2 (Ac = acetyl), using the IR/UV double resonance technique. The existence of at least five different conformers under supersonic expansion conditions is established, most of them exhibiting rather strong intramolecular H-bonds. One of the most populated conformers, however, exhibits a different H-bonding network characterized by two weak H-bonds. Comparison of the amide A and I/II experimental data with density functional theory calculations carried out on a series of selected conformations enables us to assign this conformer to two successive beta-turns along the peptide chain, the two H-bonds being of C10 type, i.e., each of them closing a 10-atom ring in the molecule. The corresponding form is found to be more stable than the 310 helix secondary structure (not observed), presumably because of specific effects due to the glycine residues.

Ultrabroadband infrared nanospectroscopic imaging

PubMed Central

Bechtel, Hans A.; Muller, Eric A.; Olmon, Robert L.; Martin, Michael C.; Raschke, Markus B.

2014-01-01

Characterizing and ultimately controlling the heterogeneity underlying biomolecular functions, quantum behavior of complex matter, photonic materials, or catalysis requires large-scale spectroscopic imaging with simultaneous specificity to structure, phase, and chemical composition at nanometer spatial resolution. However, as with any ultrahigh spatial resolution microscopy technique, the associated demand for an increase in both spatial and spectral bandwidth often leads to a decrease in desired sensitivity. We overcome this limitation in infrared vibrational scattering-scanning probe near-field optical microscopy using synchrotron midinfrared radiation. Tip-enhanced localized light–matter interaction is induced by low-noise, broadband, and spatially coherent synchrotron light of high spectral irradiance, and the near-field signal is sensitively detected using heterodyne interferometric amplification. We achieve sub-40-nm spatially resolved, molecular, and phonon vibrational spectroscopic imaging, with rapid spectral acquisition, spanning the full midinfrared (700–5,000 cm−1) with few cm−1 spectral resolution. We demonstrate the performance of synchrotron infrared nanospectroscopy on semiconductor, biomineral, and protein nanostructures, providing vibrational chemical imaging with subzeptomole sensitivity. PMID:24803431

Synthesis, spectroscopic, fluorescence properties and biological evaluation of novel Pd(II) and Cd(II) complexes of NOON tetradentate Schiff bases.

PubMed

Ali, Omyma A M

2014-01-01

The solid complexes of Pd(II) and Cd(II) with N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L(1)), and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L(2)) have been synthesized and characterized by several techniques using elemental analysis (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. Elemental analysis data proved 1:1 stoichiometry for the reported complexes while spectroscopic data indicated square planar and octahedral geometries for Pd(II) and Cd(II) complexes, respectively. The prepared ligands, Pd(II) and Cd(II) complexes exhibited intraligand (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Thermal behavior of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. Both the ligands and their complexes have been screened for antimicrobial activities. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectroscopic studies of Cr VI species in a laser produced plasma

NASA Astrophysics Data System (ADS)

Klemke, Nicolai; Nadarajan, Smijesh; Laban, Dane; Wood, James; Chetty, Dashavir; Kielpinski, David; Litvinyuk, Igor; Sang, Robert

2015-09-01

We present measurements characterizing a laser generated, highly ionized microplasma suitable to extend the cut-off energy of High Harmonic Generation (HHG) to energies up to 5 keV. The HHG process occurs when a strong ultrafast laser hits a gaseous target producing coherent radiation with a much higher photon energy than the driving laser. Commonly, noble gases are used and typical photon energies of several 100 eV are obtained. We plan to use Cr5+ species as the target for HHG as generated by a double pulse method: the first pulse creates the plasma, the second pulse is used to obtain the temperature required for Cr5+. Here, we present results on the optimization of plasma parameters such as the plasma temperature, the number density and the dynamics of Cr5+ by means of spectroscopic techniques in the optical and the XUV regime. This research is supported by Lockheed Martin and the Australian Research Council.

Polarimetric scattering behavior of materials at terahertz frequencies

NASA Astrophysics Data System (ADS)

DiGiovanni, David Anthony

Terahertz spectroscopic techniques have long been used to characterize the electromagnetic behavior of materials for use in radar, astronomy, and remote sensing applications. Spectroscopic information is valuable, but additional information about materials is present in the polarization of the scattered radiation. This thesis has investigated the polarimetric scattering behavior of various rough dielectric and metallic materials from 100 GHz to 1.55 THz. Common building materials and terrain, such as sand, gravel, soil, concrete, and roofing shingles, were studied. In order to obtain a better understanding of basic rough surface scattering phenomenology in this region of the spectrum, roughened metal and plastic samples were studied as well. The scattering behavior of these materials was studied as a function of incident angle, roughness, frequency, and polarization. Theoretical scattering models were used to compare measured results to theoretical predictions. Good agreement was observed between scattering measurements and theoretical predictions based on the small perturbation theory for the roughened metal surfaces. However, a substantial disagreement was observed for the rough dielectric surfaces and is discussed.

Spectroscopic studies on sidewall carboxylic acid functionalization of multi-walled carbon nanotubes with valine

NASA Astrophysics Data System (ADS)

Deborah, M.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

2015-03-01

The valine functionalized multi-walled carbon nanotubes (MWCNTS) were prepared and characterized by using XRD, UV-Vis, FT-IR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (0 0 2) intensity was observed for valine functionalized MWCNTs compared with oxidized MWCNTs, which is likely due to sample purification by acid washing. UV-Vis study shows the formation of valine functionalized MWCNTs. FT-IR study confirms the presence of functional groups of oxidized MWCNTs and valine functionalized MWCNTs. The ESR line shape analysis indicates that the observed EPR line shape is a Gaussian line shape. The g-values indicate that the systems are isotropic in nature. The morphology study was carried out for oxidized MWCNTs and valine functionalized MWCNTs by using SEM. The EDX spectra revealed that the high purity of oxidized MWCNTs and valine functionalized MWCNTs. The functionalization has been chosen because, functionalization of CNTs with amino acids makes them soluble and biocompatible. Thus, they have potential applications in the field of biosensors and targeted drug delivery.

Spectroscopic investigations on oxidized multi-walled carbon nanotubes

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

Anandhi, C. M. S.; Premkumar, S.; Asath, R. Mohamed

2016-05-06

The pristine multi-walled carbon nanotubes (MWCNTs) were oxidized by the ultrasonication process. The oxidized MWCNTs were characterized by the X-ray diffraction (XRD), ultraviolet–visible (UV-Vis) and Fourier transform -Raman (FT-Raman) spectroscopic techniques. The XRD analysis confirms that the oxidized MWCNTs exist in a hexagonal structure and the sharp XRD peak corresponds to the (002) Bragg’s reflection plane, which indicates that the MWCNTs have higher crystalline nature. The UV-Vis analysis confirms that the MWCNTs functionalized with the carboxylic acid. The red shift was observed corresponds to the D band in the Raman spectrum, which reveals that the reduced disordered graphitic structure ofmore » oxidized MWCNTs. The strong Raman peak was observed at 2563 cm{sup -1} corresponds to the overtone of the D band, which is the characteristic vibrational mode of oxidized MWCNTs. The carboxylic acid functionalization of MWCNTs enhances the dispersibility, which paves the way for potential applications in the field of biosensors and targeted drug delivery.« less

Spectroscopic and thermal investigations of charge-transfer complexes formed between sulfadoxine drug and different types of acceptors

NASA Astrophysics Data System (ADS)

Refat, Moamen S.

2011-01-01

Charge-transfer reactions between sulfadoxine (SDOX) as a donor with iodine (I 2), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), p-chloranil (CHL) and picric acid (PA) have been studied in solid and solution forms. The stoichiometry of all complexes was found to be 1:1 by molar ratio method between donor and acceptor at a CT-band absorption bands. The data are discussed in terms of formation constant ( KCT), molar extinction coefficient ( ɛCT), standard free energy (Δ Go), oscillator strength (ƒ), transition dipole moment ( μ), resonance energy ( RN) and ionization potential ( ID). The results indicate that the formation constant ( KCT) for the complexes were shown to be dependent upon the nature of electron acceptor, donor and polarity of solvents which were used. IR, 1H NMR and UV-Vis spectroscopic techniques, Elemental analyses (CHN) and TG-DTG investigation were used to characterize the four sulfadoxine charge-transfer complexes.

Forensic identification of blood in the presence of contaminations using Raman microspectroscopy coupled with advanced statistics: effect of sand, dust, and soil.

PubMed

Sikirzhytskaya, Aliaksandra; Sikirzhytski, Vitali; McLaughlin, Gregory; Lednev, Igor K

2013-09-01

Body fluid traces recovered at crime scenes are among the most common and important types of forensic evidence. However, the ability to characterize a biological stain at a crime scene nondestructively has not yet been demonstrated. Here, we expand the Raman spectroscopic approach for the identification of dry traces of pure body fluids to address the problem of heterogeneous contamination, which can impair the performance of conventional methods. The concept of multidimensional Raman signatures was utilized for the identification of blood in dry traces contaminated with sand, dust, and soil. Multiple Raman spectra were acquired from the samples via automatic scanning, and the contribution of blood was evaluated through the fitting quality using spectroscopic signature components. The spatial mapping technique allowed for detection of "hot spots" dominated by blood contribution. The proposed method has great potential for blood identification in highly contaminated samples. © 2013 American Academy of Forensic Sciences.

IR, 1H NMR, mass, XRD and TGA/DTA investigations on the ciprofloxacin/iodine charge-transfer complex.

PubMed

Refat, Moamen S; El-Hawary, W F; Moussa, Mohamed A A

2011-05-01

The charge-transfer complex (CTC) of ciprofloxacin drug (CIP) as a donor with iodine (I(2)) as a sigma acceptor has been studied spectrophotometrically in CHCl(3). At maximum absorption bands, the stoichiometry of CIP:iodine system was found to be 1:1 ratio according to molar ratio method. The essential spectroscopic data like formation constant (K(CT)), molar extinction coefficient (ɛ(CT)), standard free energy (ΔG°), oscillator strength (f), transition dipole moment (μ), resonance energy (R(N)) and ionization potential (I(D)) were estimated. The spectroscopic techniques such as IR, (1)H NMR, mass and UV-vis spectra and elemental analyses (CHN) as well as TG-DTG and DTA investigations were used to characterize the chelating behavior of CIP/iodine charge-transfer complex. The iodine CT interaction was associated with a presence of intermolecular hydrogen bond. The X-ray investigation was carried out to investigate the iodine doping in the synthetic CT complex. Copyright © 2011 Elsevier B.V. All rights reserved.

Cavity-Enhanced Raman Spectroscopy of Natural Gas with Optical Feedback cw-Diode Lasers.

PubMed

Hippler, Michael

2015-08-04

We report on improvements made on our previously introduced technique of cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers in the gas phase, including a new mode-matching procedure which keeps the laser in resonance with the optical cavity without inducing long-term frequency shifts of the laser, and using a new CCD camera with improved noise performance. With 10 mW of 636.2 nm diode laser excitation and 30 s integration time, cavity enhancement achieves noise-equivalent detection limits below 1 mbar at 1 bar total pressure, depending on Raman cross sections. Detection limits can be easily improved using higher power diodes. We further demonstrate a relevant analytical application of CERS, the multicomponent analysis of natural gas samples. Several spectroscopic features have been identified and characterized. CERS with low power diode lasers is suitable for online monitoring of natural gas mixtures with sensitivity and spectroscopic selectivity, including monitoring H2, H2S, N2, CO2, and alkanes.

Spectroscopic characterization of III-V semiconductor nanomaterials

NASA Astrophysics Data System (ADS)

Crankshaw, Shanna Marie

III-V semiconductor materials form a broad basis for optoelectronic applications, including the broad basis of the telecom industry as well as smaller markets for high-mobility transistors. In a somewhat analogous manner as the traditional silicon logic industry has so heavily depended upon process manufacturing development, optoelectronics often relies instead on materials innovations. This thesis focuses particularly on III-V semiconductor nanomaterials, detailed characterization of which is invaluable for translating the exhibited behavior into useful applications. Specifically, the original research described in these thesis chapters is an investigation of semiconductors at a fundamental materials level, because the nanostructures in which they appear crystallize in quite atypical forms for the given semiconductors. Rather than restricting the experimental approaches to any one particular technique, many different types of optical spectroscopies are developed and applied where relevant to elucidate the connection between the crystalline structure and exhibited properties. In the first chapters, for example, a wurtzite crystalline form of the prototypical zincblende III-V binary semiconductor, GaAs, is explored through polarization-dependent Raman spectroscopy and temperature-dependent photoluminescence, as well as second-harmonic generation (SHG). The altered symmetry properties of the wurtzite crystalline structure are particularly evident in the Raman and SHG polarization dependences, all within a bulk material realm. A rather different but deeply elegant aspect of crystalline symmetry in GaAs is explored in a separate study on zincblende GaAs samples quantum-confined in one direction, i.e. quantum well structures, whose quantization direction corresponds to the (110) direction. The (110) orientation modifies the low-temperature electron spin relaxation mechanisms available compared to the usual (001) samples, leading to altered spin coherence times explored through a novel spectroscopic technique first formulated for the rather different purpose of dispersion engineering for slow-light schemes. The frequency-resolved technique combined with the unusual (110) quantum wells in a furthermore atypical waveguide experimental geometry has revealed fascinating behavior of electron spin splitting which points to the possibility of optically orienting electron spins with linearly polarized light---an experimental result supporting a theoretical description of the phenomenon itself only a few years old. Lastly, to explore a space of further-restricted dimensionality, the final chapters describe InP semiconductor nanowires with dimensions small enough to be considered truly one-dimensional. Like the bulk GaAs of the first few chapters, the InP nanowires here crystallize in a wurtzite structure. In the InP nanowire case, though, the experimental techniques explored for characterization are temperature-dependent time-integrated photoluminescence at the single-wire level (including samples with InAsP insertions) and time-resolved photoluminescence at the ensemble level. The carrier dynamics revealed through these time-resolved studies are the first of their kind for wurtzite InP nanowires. The chapters are thus ordered as a progression from three (bulk), to two (quantum well), to one (nanowire), to zero dimensions (axially-structured nanowire), with the uniting theme the emphasis on connecting the semiconductor nanomaterials' crystallinity to its exhibited properties by relevant experimental spectroscopic techniques, whether these are standard methods or effectively invented for the case at hand.

Comparison between infrared and Raman spectroscopic analysis of maturing rabbit cortical bone.

PubMed

Turunen, Mikael J; Saarakkala, Simo; Rieppo, Lassi; Helminen, Heikki J; Jurvelin, Jukka S; Isaksson, Hanna

2011-06-01

The molecular composition of the organic and inorganic matrices of bone undergoes alterations during maturation. The aim of this study was to compare Fourier transform infrared (FT-IR) and near-infrared (NIR) Raman microspectroscopy techniques for characterization of the composition of growing and developing bone from young to skeletally mature rabbits. Moreover, the specificity and differences of the techniques for determining bone composition were clarified. The humeri of female New Zealand White rabbits, with age range from young to skeletally mature animals (four age groups, n = 7 per group), were studied. Spectral peak areas, intensities, and ratios related to organic and inorganic matrices of bone were analyzed and compared between the age groups and between FT-IR and Raman microspectroscopic techniques. Specifically, the degree of mineralization, type-B carbonate substitution, crystallinity of hydroxyapatite (HA), mineral content, and collagen maturity were examined. Significant changes during maturation were observed in various compositional parameters with one or both techniques. Overall, the compositional parameters calculated from the Raman spectra correlated with analogous parameters calculated from the IR spectra. Collagen cross-linking (XLR), as determined through peak fitting and directly from the IR spectra, were highly correlated. The mineral/matrix ratio in the Raman spectra was evaluated with multiple different peaks representing the organic matrix. The results showed high correlation with each other. After comparison with the bone mineral density (BMD) values from micro-computed tomography (micro-CT) imaging measurements and crystal size from XRD measurements, it is suggested that Raman microspectroscopy is more sensitive than FT-IR microspectroscopy for the inorganic matrix of the bone. In the literature, similar spectroscopic parameters obtained with FT-IR and NIR Raman microspectroscopic techniques are often compared. According to the present results, however, caution is required when performing this kind of comparison.

Ultrafast and nonlinear surface-enhanced Raman spectroscopy.

PubMed

Gruenke, Natalie L; Cardinal, M Fernanda; McAnally, Michael O; Frontiera, Renee R; Schatz, George C; Van Duyne, Richard P

2016-04-21

Ultrafast surface-enhanced Raman spectroscopy (SERS) has the potential to study molecular dynamics near plasmonic surfaces to better understand plasmon-mediated chemical reactions such as plasmonically-enhanced photocatalytic or photovoltaic processes. This review discusses the combination of ultrafast Raman spectroscopic techniques with plasmonic substrates for high temporal resolution, high sensitivity, and high spatial resolution vibrational spectroscopy. First, we introduce background information relevant to ultrafast SERS: the mechanisms of surface enhancement in Raman scattering, the characterization of plasmonic materials with ultrafast techniques, and early complementary techniques to study molecule-plasmon interactions. We then discuss recent advances in surface-enhanced Raman spectroscopies with ultrafast pulses with a focus on the study of molecule-plasmon coupling and molecular dynamics with high sensitivity. We also highlight the challenges faced by this field by the potential damage caused by concentrated, highly energetic pulsed fields in plasmonic hotspots, and finally the potential for future ultrafast SERS studies.

The relationship between the surface composition and electrical properties of corrosion films formed on carbon steel in alkaline sour medium: an XPS and EIS study.

PubMed

Galicia, Policarpo; Batina, Nikola; González, Ignacio

2006-07-27

This work studies the evolution of 1018 carbon steel surfaces during 3-15 day immersion in alkaline sour medium 0.1 M (NH4)2S and 10 ppm CN(-) as (NaCN). During this period of time, surfaces were jointly characterized by electrochemical techniques in situ (electrochemical impedance spectroscopy, EIS) and spectroscopic techniques ex situ (X-ray photoelectron spectroscopy, XPS). The results obtained by these techniques allowed for a description of electrical and chemical properties of the films of corrosion products formed at the 1018 steel surface. There is an interconversion cycle of chemical species that form films of corrosion products whose conversion reactions favor two different types of diffusions inside the films: a chemical diffusion of iron cations and a typical diffusion of atomic hydrogen. These phenomena jointly control the passivity of the interface attacked by the corrosive medium.

Assessment of recent advances in measurement techniques for atmospheric carbon dioxide and methane observations

NASA Astrophysics Data System (ADS)

Zellweger, Christoph; Emmenegger, Lukas; Firdaus, Mohd; Hatakka, Juha; Heimann, Martin; Kozlova, Elena; Spain, T. Gerard; Steinbacher, Martin; van der Schoot, Marcel V.; Buchmann, Brigitte

2016-09-01

Until recently, atmospheric carbon dioxide (CO2) and methane (CH4) measurements were made almost exclusively using nondispersive infrared (NDIR) absorption and gas chromatography with flame ionisation detection (GC/FID) techniques, respectively. Recently, commercially available instruments based on spectroscopic techniques such as cavity ring-down spectroscopy (CRDS), off-axis integrated cavity output spectroscopy (OA-ICOS) and Fourier transform infrared (FTIR) spectroscopy have become more widely available and affordable. This resulted in a widespread use of these techniques at many measurement stations. This paper is focused on the comparison between a CRDS "travelling instrument" that has been used during performance audits within the Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) with instruments incorporating other, more traditional techniques for measuring CO2 and CH4 (NDIR and GC/FID). We demonstrate that CRDS instruments and likely other spectroscopic techniques are suitable for WMO/GAW stations and allow a smooth continuation of historic CO2 and CH4 time series. Moreover, the analysis of the audit results indicates that the spectroscopic techniques have a number of advantages over the traditional methods which will lead to the improved accuracy of atmospheric CO2 and CH4 measurements.

A FIVE-YEAR SPECTROSCOPIC AND PHOTOMETRIC CAMPAIGN ON THE PROTOTYPICAL {alpha} CYGNI VARIABLE AND A-TYPE SUPERGIANT STAR DENEB

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

Richardson, N. D.; Morrison, N. D.; Kryukova, E. E.

2011-01-15

Deneb is often considered the prototypical A-type supergiant and is one of the visually most luminous stars in the Galaxy. A-type supergiants are potential extragalactic distance indicators, but the variability of these stars needs to be better characterized before this technique can be considered reliable. We analyzed 339 high-resolution echelle spectra of Deneb obtained over the five-year span of 1997 through 2001 as well as 370 Stroemgren photometric measurements obtained during the same time frame. Our spectroscopic analysis included dynamical spectra of the H{alpha} profile, H{alpha} equivalent widths, and radial velocities measured from Si II {lambda}{lambda} 6347, 6371. Time-series analysismore » reveals no obvious cyclic behavior that proceeds through multiple observing seasons, although we found a suspected 40 day period in two, non-consecutive observing seasons. Some correlations are found between photometric and radial velocity data sets and suggest radial pulsations at two epochs. No correlation is found between the variability of the H{alpha} profiles and that of the radial velocities or the photometry. Lucy found evidence that Deneb was a long-period single-lined spectroscopic binary star, but our data set shows no evidence for radial velocity variations caused by a binary companion.« less

The optical characterization of organometallic complex thin films by spectroscopic ellipsometry and photovoltaic diode application

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

Özaydın, C.; Güllü, Ö., E-mail: omergullu@gmail.com; Pakma, O.

2016-05-15

Highlights: • Optical properties and thickness of the A novel organometallic complex (OMC) film were investigated by spectroscopic ellipsometry (SE). • Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated • This paper presents the I–V analysis of Au/OMC/n-Si MIS diode. • Current–voltage and photovoltaic properties of the diode were investigated. - Abstract: In this work, organometallic complex (OMC) films have been deposited onto glass or silicon substrates by spin coating technique and their photovoltaic application potential has been investigated. Optical properties and thickness of the film have been investigated by spectroscopic ellipsometry (SE). Also, transmittance spectrum has been taken by UV/vismore » spectrophotometer. The optical method has been used to determine the band gap value of the films. Also, Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated. Current–voltage and photovoltaic properties of the structure were investigated. The ideality factor (n) and barrier height (Φ{sub b}) values of the diode were found to be 2.89 and 0.79 eV, respectively. The device shows photovoltaic behavior with a maximum open-circuit voltage of 396 mV and a short circuit current of 33.8 μA under 300 W light.« less

Spectroscopic and theoretical investigation of conformational changes of proteins by synthesized pyrimidine derivative and its sensitivity towards FRET application

NASA Astrophysics Data System (ADS)

Ghosh, Swadesh; Singharoy, Dipti; Bhattacharya, Subhash Chandra

2018-04-01

Interest in synthesizing and characterizing (IR, NMR and HRMS spectroscopic methods) a pyrimidine based Schiff-base ligand, 2-(2-(Anthracen-9-ylmethylene) hydrazinyl)-4,6-dimethyl pyrimidine (ANHP) has been developed for its application to ascertain the conformational change of protein and sensitivity towards fluorescence resonance energy transfer (FRET) process. Location of ANHP in bovine serum albumin (BSA) and human serum albumin (HSA) proteins environment has been determined using different spectroscopic techniques. Weakly fluorescent ANHP have shown greater protein induced fluorescence enhancement (PIFE) in case of HSA than BSA, though in both cases energy transfer efficiency are almost same but difference in binding constant values encourages us to find the location of ANHP within the complex protein environment. From the FRET parameter and α-helicity change, it has been found that ANHP bound with Trp-214 of HSA and surface Trp-134 of BSA. Conformational changes of proteins have been observed more for HSA than BSA in presence of ANHP, which has confirmed the location of ANHP in both the protein environments. Coupled with experimental studies, molecular docking analysis has also been done to explain the locations and distance dependent FRET process of ANHP in both proteins.

Synthesis, crystal structure, spectroscopic characterization, Hirshfeld surface analysis, and DFT calculations of 1,4-dimethyl-2-oxo-pyrimido[1,2-a]benzimidazole hydrate

NASA Astrophysics Data System (ADS)

El Bakri, Youness; Anouar, El Hassane; Ramli, Youssef; Essassi, El Mokhtar; Mague, Joel T.

2018-01-01

Imidazopyrimidine derivatives are organic synthesized compounds with a pyrimido[1,2-a]benzimidazole as basic skeleton. They are known for their various biological properties and as an important class of compounds in medicinal chemistry. A new 1,4-dimethyl-2-oxo-pyrimido[1,2-a]benzimidazole hydrate derivative of the tilted group has been synthesized and characterized by spectroscopic techniques NMR and FT-IR; and by a single crystal X-ray diffraction. The X-ray results showed that the tricyclic core of the title compound, C12H11N3O·H2O, is almost planar. The molecules stack along the a-axis direction in head-to- tail fashion through π-stacking interactions involving all three rings. The stacks are tied together by direct Csbnd H⋯O hydrogen bonds and by Osbnd H⋯O, Osbnd N⋯N and Csbnd H⋯O hydrogen bonds with the lattice water. DFT calculations at B3LYP/6-311++G(d,p) in gas phase an polarizable continuum model have been carried out to predict the spectral and geometrical data of the tilted compound. The obtained results showed relatively good correlations between the predicted and experimental data with correlation coefficients higher than 98%.

Synthesis, spectroscopic characterization and biological activity of cis-[Ru(hesperidin)(1,10‧-phenanthroline)2](PF6) complex

NASA Astrophysics Data System (ADS)

Oliveira, Regina M. M.; de Souza Daniel, Juliana F.; Carlos, Rose M.

2013-01-01

The new complex cis-[Ru(phen)2(hesperidin)](PF6), complex 1, was synthesized and characterized by analytical (ESI-MS+, EA (C, H, N)) and spectroscopic (FTIR, UV-vis, 1H and 13C NMR) techniques and cyclic voltammetry. Complex 1 is chemically stable in the solid state and in organic solvents such as ethanol, methanol, acetone, and acetonitrile, as shown by spectrophotometric analysis. 1 is also photochemically and chemically stable (pH effects) and more hydrosoluble (518.83 ± 0.91 g mL-1) than free hesperidin (5.92 g mL-1). In accordance with this, the lipophilicity value in aqueous-octanol solution for 1 was -1.28, indicating its high hydrophilic characteristic. Although complex 1 showed to be essentially noncytotoxic, IC50 > 1.0 mmol L-1 as evaluated in the human cervical cancer cells line HeLa, it exhibited a moderate capacity of inhibiting the catalytic activity of the acetylcholinaesterase enzyme, IC50 = 63.6 mol L-1. The Lineweaver-Burk plot and the respective secondary replot indicated that the AChE inhibition was noncompetitive and reversible. These findings shows that complexation of the hesperidin improves physicochemical characteristics and increases the perspectives for development and medical applications of new bioactive-metal complexes.

Diagnostics of hydrogen plasma with in situ optical emission and silicon probes

NASA Astrophysics Data System (ADS)

Lee, Szetsen; Chung, Yi-Jie

2005-11-01

In this work, an approach has been adopted to explore plasma properties by combining an in situ optical emission technique with a contact angle measurement. Hydrogen plasma was generated with a radio-frequency power source. The plasma parameters such as number densities and temperatures were derived from the optical emission spectroscopic data. Small silicon chips were placed at various positions inside a discharge tube as probes for the plasma conditions. The hydrogen-plasma-treated silicon chip surfaces were characterized with the contact angle measurement method. The change of wettability on the silicon surface was observed with various plasma treatment times. The spectroscopic information about the plasma is correlated with the results of the surface characterization. It is found that the rate of the increasing hydrophilicity is sensitive to the amount of helium added and the location in the discharge tube. A simple model describing the relation between the surface coverage area of water droplet and the variation of contact angle has been established. We have proposed plasma excitation and reaction mechanisms for the observed correlation between plasma temperatures and the wettability of the silicon surface. It shows that small silicon chips can serve as "litmus tests" for the plasma conditions without introducing too much perturbation.

Syntheses, spectroscopic properties and molecular structure of silver phytate complexes - IR, UV-VIS studies and DFT calculations

NASA Astrophysics Data System (ADS)

Zając, A.; Dymińska, L.; Lorenc, J.; Ptak, M.; Hanuza, J.

2018-03-01

Silver phytate IP6, IP6Ag, IP6Ag2 and IP6Ag3 complexes in the solid state have been synthesized changing the phosphate to metal mole ratio. The obtained products have been characterized by means of chemical and spectroscopic studies. Attenuated total reflection Fourier transform infrared technique and Raman microscope were used in the measurements. These results were discussed in terms of DFT (Density Functional Theory) quantum chemical calculations using the B3LYP/6-31G(d,p) approach. The molecular structures of these compounds have been proposed on the basis of group theory and geometry optimization taking into account the shape and the number of the observed bands corresponding to the stretching and bending vibrations of the phosphate group and metal-oxygen polyhedron. The role of inter- and intra-hydrogen bonds in stabilization of the structure has been discussed. It was found that three types of hydrogen bonds appear in the studied compounds: terminal, and those engaged in the inter- and intra-molecular interactions. The Fermi resonance as a result of the strong intra-molecular Osbnd H⋯O hydrogen bonds was discovered. Electron absorption spectra have been measured to characterize the electron properties of the studied complexes and their local symmetry.

Spectroscopic Characterization of the Water Oxidation Intermediates in the Blue Dimer Ru-Based Catalyst for Artificial Photosynthesis

NASA Astrophysics Data System (ADS)

Moonshiram, Dooshaye; Pushkar, Yulia; Jurss, Jonah; Concepcion, Javier; Meyer, Thomas; Zakharova, Taisiya; Alperovich, Igor

2012-02-01

Utilization of sunlight requires solar capture, light-to-energy conversion and storage. One effective way to store energy is to convert it into chemical energy by fuel-forming reactions, such as water splitting into hydrogen and oxygen. Ruthenium complexes are among few molecular-defined catalysts capable of water splitting. Mechanistic insights about such catalysts can be acquired by spectroscopic analysis of short-lived intermediates of catalytic water oxidation. Use of techniques such as EPR and X-ray absorption spectroscopy (XAS) are used to determine electronic requirements of catalytic water oxidation. About 30 years ago Meyer and coworkers reported first ruthenium-based catalyst for water oxidation, the ``blue dimer''. We performed EPR studies and characterized structures and electronic configurations of intermediates of water oxidation by the ``blue dimer''. Intermediates were prepared chemically by oxidation of Ru-complexes with defined number of Ce (IV) equivalents and freeze-quenched at controlled times. Changes in oxidation state of Ru atom were detected by XANES at Ru K-edges. K-edges are sensitive to changes in Ru oxidation state for Blue Dimer [3,3]^4+, [3,4]^4+, [3,4]'^4+ and [4,5]^3+ allowing a clear assignment of Ru oxidation state in intermediates. EXAFS demonstrated structural changes.

Characterization and spectroscopic studies of multi-component calcium zinc bismuth phosphate glass ceramics doped with iron ions

NASA Astrophysics Data System (ADS)

Kumar, A. Suneel; Narendrudu, T.; Suresh, S.; Ram, G. Chinna; Rao, M. V. Sambasiva; Tirupataiah, Ch.; Rao, D. Krishna

2018-04-01

Glass ceramics with the composition 10CaF2-20ZnO-(15-x)Bi2O3-55P2O5:x Fe2O3(0≤x≤2.5) were synthesized by melt-quenching technique and heat treatment. These glass ceramics were characterized by XRD and SEM. Spectroscopic studies such as optical absorption, EPR were also carried out on these glass ceramics. From the absorption spectra the observed bands around 438 and 660nm are the octahedral transitions of Fe3+ (d5) ions and another band at about 536 nm is the tetrahedral transition of Fe3+ (d5) ions. The absorption spectrum also consist of a band around 991 nm and is attributed to the octahedral transition of Fe2+ ions. The EPR spectra of the prepared glass ceramics have exhibited two resonance signals one at g1=4.32 and another signal at g2=2.008. The observed decrease in band gap energy up to 2 mol% Fe2O3 doped glass ceramics is an evidence for the change of environment around iron ions and ligands from more covalent to less covalent (ionic) and induces higher concentration of NBOs which causes the depolymerization of the glass ceramic network.

Lupane, friedelane, oleanane, and ursane triterpenes from the stem of Siphonodon celastrineus Griff.

PubMed

Kaweetripob, Wirongrong; Mahidol, Chulabhorn; Prawat, Hunsa; Ruchirawat, Somsak

2013-12-01

Twenty-one triterpenes consisting of a lupane derivative, two friedelanes, an oleanane derivative, and 17 ursane-type triterpenoids, together with three known triterpenes, three sterols, a fatty acid, a sesquiterpene alkaloid, and a glycerol derivative, were isolated from the stem of Siphonodon celastrineus. Their structures were characterized by various spectroscopic techniques, as well as comparison with literature data. Twenty-seven metabolites of these were evaluated for cytotoxic activity against six human cancer cell lines. The biosynthetic formation of a 1,4-dioxane bridge is also discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis and anion recognition studies of novel bis (4-hydroxycoumarin) methane azo dyes

NASA Astrophysics Data System (ADS)

Panitsiri, Amorn; Tongkhan, Sukanya; Radchatawedchakoon, Widchaya; Sakee, Uthai

2016-03-01

Four new bis (4-hydroxycoumarin) methane azo dyes were synthesized by the condensation of 4-hydroxycoumarin with four different azo salicylaldehydes and their structures were characterized by FT-IR, 1H NMR, 13C NMR, HRMS. Anion binding ability in dimethyl sulfoxide (DMSO) solutions with tetrabutylammonium (TBA) salts (F-, Cl-, Br-, I-, AcO- and H2PO4-) was investigated by the naked eye, as well as UV-visible spectroscopy. The sensor shows selective recognition towards fluoride and acetate. The binding affinity of the sensors with fluoride and acetate was calculated using UV-visible spectroscopic technique.

Part 1: Synthesis and visible absorption spectra of some new monoazo dyes derived from ethyl 2-amino-4-(4";-substitutedphenyl)thiophenes

NASA Astrophysics Data System (ADS)

Babür, Banu; Ertan, Nermin

2014-10-01

Series of monoazo dyes from some ethyl 2-amino-4-(4";-substitutedphenyl) thiophenes were prepared and characterized. The structure of the substances was confirmed by FT-IR, 1H NMR and mass spectroscopic techniques. The relationship among the structure of the dyes, their absorption characteristics and the solvatochromic and halochromic behaviors of the dyes were investigated. Introduction of electron-accepting substituent into the diazo moiety results in large bathochromic shifts in all solvents used. The dyes exhibited positive solvatochromism and their solvatochromic properties were discussed in relation to tautomerism.

Spectroscopic, cyclic voltammetric and biological studies of transition metal complexes with mixed nitrogen-sulphur (NS) donor macrocyclic ligand derived from thiosemicarbazide

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Gupta, Lokesh Kumar; Sangeetika

2005-11-01

The complexation of new mixed thia-aza-oxa macrocycle viz., 2,12-dithio-5,9,14,18-tetraoxo-7,16-dithia-1,3,4,10,11,13-hexaazacyclooctadecane containing thiosemicarba-zone unit with a series of transition metals Co(II), Ni(II) and Cu(II) has been investigated, by different spectroscopic techniques. The structural features of the ligand have been studied by EI-mass, 1H NMR and IR spectral techniques. Elemental analyses, magnetic moment susceptibility, molar conductance, IR, electronic, and EPR spectral studies characterized the complexes. Electronic absorption and IR spectra of the complexes indicate octahedral geometry for chloro, nitrato, thiocyanato or acetato complexes. The dimeric and neutral nature of the sulphato complexes are confirmed from magnetic susceptibility and low conductance values. Electronic spectra suggests square-planar geometry for all sulphato complexes. The redox behaviour was studied by cyclic voltammetry, show metal-centered reduction processes for all complexes. The complexes of copper show both oxidation and reduction process. The redox potentials depend on the conformation of central atom in the macrocyclic complexes. Newly synthesized macrocyclic ligand and its transition metal complexes show markedly growth inhibitory activity against pathogenic bacterias and plant pathogenic fungi under study. Most of the complexes have higher activity than that of the metal free ligand.

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.

Hemoglobin consumption by P. falciparum in individual erythrocytes imaged via quantitative phase spectroscopy

NASA Astrophysics Data System (ADS)

Rinehart, Matthew T.; Park, Han Sang; Walzer, Katelyn A.; Chi, Jen-Tsan Ashley; Wax, Adam

2016-04-01

Plasmodium falciparum infection causes structural and biochemical changes in red blood cells (RBCs). To quantify these changes, we apply a novel optical technique, quantitative phase spectroscopy (QPS) to characterize individual red blood cells (RBCs) during the intraerythrocytic life cycle of P. falciparum. QPS captures hyperspectral holograms of individual RBCs to measure spectroscopic changes across the visible wavelength range (475-700 nm), providing complex information, i.e. amplitude and phase, about the light field which has interacted with the cell. The complex field provides complimentary information on hemoglobin content and cell mass, which are both found to dramatically change upon infection by P. falciparum. Hb content progressively decreases with parasite life cycle, with an average 72.2% reduction observed for RBCs infected by schizont-stage P. falciparum compared to uninfected cells. Infection also resulted in a 33.1% reduction in RBC’s optical volume, a measure of the cells’ non-aqueous components. Notably, optical volume is only partially correlated with hemoglobin content, suggesting that changes in other dry mass components such as parasite mass may also be assessed using this technique. The unique ability of QPS to discriminate individual healthy and infected cells using spectroscopic changes indicates that the approach can be used to detect disease.

Spectroscopic methods for the photodiagnosis of nonmelanoma skin cancer.

PubMed

Drakaki, Eleni; Vergou, Theognosia; Dessinioti, Clio; Stratigos, Alexander J; Salavastru, Carmen; Antoniou, Christina

2013-06-01

The importance of dermatological noninvasive imaging techniques has increased over the last decades, aiming at diagnosing nonmelanoma skin cancer (NMSC). Technological progress has led to the development of various analytical tools, enabling the in vivo/in vitro examination of lesional human skin with the aim to increase diagnostic accuracy and decrease morbidity and mortality. The structure of the skin layers, their chemical composition, and the distribution of their compounds permits the noninvasive photodiagnosis of skin diseases, such as skin cancers, especially for early stages of malignant tumors. An important role in the dermatological diagnosis and disease monitoring has been shown for promising spectroscopic and imaging techniques, such as fluorescence, diffuse reflectance, Raman and near-infrared spectroscopy, optical coherence tomography, and confocal laser-scanning microscopy. We review the use of these spectroscopic techniques as noninvasive tools for the photodiagnosis of NMSC.

Spectroscopic methods for the photodiagnosis of nonmelanoma skin cancer

NASA Astrophysics Data System (ADS)

Drakaki, Eleni; Vergou, Theognosia; Dessinioti, Clio; Stratigos, Alexander J.; Salavastru, Carmen; Antoniou, Christina

2013-06-01

The importance of dermatological noninvasive imaging techniques has increased over the last decades, aiming at diagnosing nonmelanoma skin cancer (NMSC). Technological progress has led to the development of various analytical tools, enabling the in vivo/in vitro examination of lesional human skin with the aim to increase diagnostic accuracy and decrease morbidity and mortality. The structure of the skin layers, their chemical composition, and the distribution of their compounds permits the noninvasive photodiagnosis of skin diseases, such as skin cancers, especially for early stages of malignant tumors. An important role in the dermatological diagnosis and disease monitoring has been shown for promising spectroscopic and imaging techniques, such as fluorescence, diffuse reflectance, Raman and near-infrared spectroscopy, optical coherence tomography, and confocal laser-scanning microscopy. We review the use of these spectroscopic techniques as noninvasive tools for the photodiagnosis of NMSC.

MicroRaman, PXRD, EDS and microscopic investigation of magnesium calcite biomineral phases. The case of sea urchin biominerals

NASA Astrophysics Data System (ADS)

Borzęcka-Prokop, B.; Wesełucha-Birczyńska, A.; Koszowska, E.

2007-02-01

This study concerns Mg-calcite characterization (and in particular molecular structure and microstructural studies of mineral phases) of a sea urchin mineralised test and spines. Sea urchins are spiny sea animals (kingdom Animalia, phylum Echinodermata, class Echinoidea). Microscopic observations, SEM, EDS, PXRD and spectroscopic microRaman methods have been applied to characterize the biomineral parts of the sea urchin. The latter technique is very useful in research of biological systems and especially suitable for monitoring differences within biomineral phases exhibiting varieties of morphological forms. Crystalline magnesium calcium carbonate, Mg xCa 1- xCO 3 (magnesian calcite; space group R-3 cH; a = 4.9594(8) Å, c = 16.886(6) Å), has been identified as the predominant biomineral component.

Synthesis, characterization and antibacterial study of tripodal tris-(N-benzoylthioureido)ethylamine

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

Adan, Dalina; Yamin, Bohari; Leng, Ong Wei

A new tripodal tris-(N-benzoylthiouredoethyl)amine has been successfully synthesized and characterized by spectroscopic technique such as FTIR, ESI MS, {sup 1}H and {sup 13}C NMR. The microanalysis data is in a good agreement with the expected molecular formula. The {sup 1}H NMR chemical shift for both amide and thioamide proton are at lower field than their normal value indicates the presence of the hydrogen bond between the carbonyl oxygen atom and thioamide hydrogen. This is possible when the benzoyl group adopt a trans configuration againts thione group along the C-N bond. The compound has been tested for antibacterial activity against threemore » selected bacteria namely Staphylococcus aureus, Proteus vulgaris and Pseudomanas aeroginosa but there is no significant activities observed.« less

Semisynthesis, Characterization and Evaluation of New Adenosine Derivatives as Antiproliferative Agents.

PubMed

Valdés Zurita, Francisco; Brown Vega, Nelson; Gutiérrez Cabrera, Margarita

2018-05-08

We describe the semisynthesis and biological effects of adenosine derivatives, which were anticipated to function as agonists for the A₃ receptor. Molecular docking was used to select candidate compounds. Fifteen nucleoside derivatives were obtained through nucleophilic substitutions of the N ⁶-position of the nucleoside precursor 6-chloropurine riboside by amines of different origin. All compounds were purified by column chromatography and further characterized by spectroscopic and spectrometric techniques, showing moderate yield. These molecules were then evaluated for their antiproliferative activity in human gastric cancer cells expressing the A₃ receptor. We found that the compounds obtained have antiproliferative activity and that new structural modifications can enhance their biological activity. The ADME (Absorption, Distribution, Metabolism and Excretion) properties of the most active compounds were also evaluated theoretically.

Photoelectron spectroscopic and microspectroscopic probes of ferroelectrics

NASA Astrophysics Data System (ADS)

Tǎnase, Liviu C.; Abramiuc, Laura E.; Teodorescu, Cristian M.

2017-12-01

This contribution is a review of recent aspects connected with photoelectron spectroscopy of free ferroelectric surfaces, metals interfaced with these surfaces, graphene-like layers together with some exemplifications concerning molecular adsorption, dissociations and desorptions occurring from ferroelectrics. Standard photoelectron spectroscopy is used nowadays in correlation with other characterization techniques, such as piezoresponse force microscopy, high resolution transmission electron spectroscopy, and ferroelectric hysteresis cycles. In this work we will concentrate mainly on photoelectron spectroscopy and spectro-microscopy characterization of ferroelectric thin films, starting from atomically clean ferroelectric surfaces of lead zirco-titanate, then going towards heterostructures using this material in combination with graphene-like carbon layers or with metals. Concepts involving charge accumulation and depolarization near surface will be revisited by taking into account the newest findings in this area.

Μicro-Raman spectroscopy for the characterization of rock-art pigments from Abrigo del Águila (Badajoz - Spain)

NASA Astrophysics Data System (ADS)

Rosina, P.; Gomes, H.; Collado, H.; Nicoli, M.; Volpe, L.; Vaccaro, C.

2018-06-01

Micro-Raman spectroscopic technique allowed the characterization of organic and inorganic pigments of different colours sampled from a rock-art shelter named Abrigo del Aguila, located in the district of Badajoz, Cabeza del Buey (Extremadura - Spain). Micro-Raman analyses has been coupled with SEM observation and elemental analyses (EDS). The white and the black colours, used for non-representative figures, have been identified respectively as anatase and amorphous carbon, while two different type of red pigment has been found on figurative representations. The darker one, sampled, from a sun-figure, comprises an indeterminate organic compound beside of hematite. The second one, sampled from an anthropomorphic figure, is of a brilliant red and only hematite has been recognized in it.

Synthesis, spectroscopic characterization and pH dependent photometric and electrochemical fate of Schiff bases.

PubMed

Rauf, Abdur; Shah, Afzal; Abbas, Saghir; Rana, Usman Ali; Khan, Salah Ud-Din; Ali, Saqib; Zia-Ur-Rehman; Qureshi, Rumana; Kraatz, Heinz-Bernhard; Belanger-Gariepy, Francine

2015-03-05

A new Schiff base, 1-((4-bromophenylimino) methyl) naphthalen-2-ol (BPIMN) was successfully synthesized and characterized by (1)H NMR, (13)C NMR, FTIR and UV-Vis spectroscopy. The results were compared with a structurally related Schiff base, 1-((4-chlorophenylimino) methyl) naphthalen-2-ol (CPIMN). The photometric and electrochemical fate of BPIMN and CPIMN was investigated in a wide pH range. The experimental findings were supported by quantum mechanical approach. The redox mechanistic pathways were proposed on the basis of results obtained electrochemical techniques. Moreover, pH dependent UV-Vis spectroscopy of BPIMN and CPIMN was carried out and the appearance of isosbestic points indicated the existence of these compounds in different tautomeric forms. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis and molecular characterization of chitosan based polyurethane elastomers using aromatic diisocyanate.

PubMed

Zia, Khalid Mahmood; Anjum, Sohail; Zuber, Mohammad; Mujahid, Muhammad; Jamil, Tahir

2014-05-01

The present research work was performed to synthesize a new series of chitosan based polyurethane elastomers (PUEs) using poly(ɛ-caprolactone) (PCL). The chitosan based PUEs were prepared by step-growth polymerization technique using poly(ɛ-caprolactone) (PCL) and 2,4-toluene diisocyanate (TDI). In the second step the PU prepolymer was extended with different mole ratios of chitosan and 1,4-butane diol (BDO). Molecular engineering was carried out during the synthesis. The conventional spectroscopic characterization of the synthesized samples using FT-IR confirms the existence of the proposed chitosan based PUEs structure. Internal morphology of the prepared PUEs was studied using SEM analysis. The SEM images confirmed the incorporation of chitosan molecules into the PU backbone. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel biosynthesis of Ag-hydroxyapatite: Structural and spectroscopic characterization

NASA Astrophysics Data System (ADS)

Ruíz-Baltazar, Álvaro de Jesús; Reyes-López, Simón Yobanny; Silva-Holguin, Pamela Nair; Larrañaga, Daniel; Estévez, Miriam; Pérez, Ramiro

2018-06-01

Silver-doped hydroxyapatite (Ag-HAP) was obtained by green synthesis route. The dopant silver nanoparticles (AgNPs) were obtained by biosynthesis based on Melissa officinalis extract. This research is focused on the characterization and the use of the nontoxic and environment-friendly Ag-HAP nanocomposite. The structural and morphological characterization of Ag-HAP nanocomposite was carried out by scanning electron microscopy (SEM), X-ray diffraction, Fourier-transform infrared (FT-IR) and Raman spectroscopy. The obtained nanoparticles exhibited a great interaction with the HAP matrix, performing an Ag-HAP nanocomposite. Changes in the structure of the Ag-HAP nanocomposite were corroborated by the different characterization techniques. Additionally, a homogeneous distribution of the AgNPs on the HAP structure was observed. The heterogeneous nucleation process employed to doping the HAP, offer a functional route to obtain a green composite with potentials applications in multiple fields, such as tissue engineering, bone repair as well as protein. These properties can be evaluated in subsequent studies.

New spectroscopic tools and techniques for characterizing M dwarfs and discovering their planets in the near-infrared

NASA Astrophysics Data System (ADS)

Terrien, Ryan C.

M dwarfs are the least massive and most common stars in the Galaxy. Due to their prevalence and long lifetimes, these diminutive stars play an outsize role in several fields of astronomical study. In particular, it is now known that they commonly host planetary systems, and may be the most common hosts of Earth-size, rocky planets in the habitable zone. A comprehensive understanding of M dwarfs is crucial for understanding the origins and conditions of their planetary systems, including their potential habitability. Such an understanding depends on methods for precisely and accurately measuring their properties. These tools have broader applicability as well, underlying the use of M dwarfs as fossils of Galactic evolution, and helping to constrain the structures and interiors of these stars. The measurement of the fundamental parameters of M dwarfs is encumbered by their spectral complexity. Unlike stars of spectral type F, G, or K that are similar to our G type Sun, whose spectra are dominated by continuum emission and atomic features, the cool atmospheres of M dwarfs are dominated by complex molecular absorption. Another challenge for studies of M dwarfs is that these stars are optically faint, emitting much of their radiation in the near-infrared (NIR). The availability and performance of NIR spectrographs have lagged behind those of optical spectrographs due to the challenges of producing low-noise, high-sensitivity NIR detector arrays, which have only recently become available. This thesis discusses two related lines of work that address these challenges, motivated by the development of the Habitable Zone Planet Finder (HPF), a NIR radial velocity (RV) spectrograph under development at Penn State that will search for and confirm planets around nearby M dwarfs. This work includes the development and application of new NIR spectroscopic techniques for characterizing M dwarfs, and the development and optimization of new NIR instrumentation for HPF. The first line of work is centered on a large NIR spectroscopic survey of nearby M dwarfs, undertaken to characterize potential targets for HPF. This survey, and new techniques for measuring M dwarf metallicity, are the subject of Chapter 2. These data will provide crucial information to assess planetary composition, and the stellar metallicities will help us understand the process of planet formation around M dwarfs. These techniques have also enabled strong tests of low-mass stellar models in the benchmark eclipsing binary system CM Draconis, and have helped identify potential directions for improvement in the models, as presented in Chapter 3. The development of new spectroscopic indices for measuring M dwarf luminosity, radius, and potentially alpha-element abundance is discussed in Chapter 4. Finally, Chapter 5 presents a synthesis of these M dwarf characterization techniques and radial velocity (RV) measurements from the SDSS-III APOGEE spectrograph, which we applied to confirm and characterize the first M dwarfs in the nearby Coma Berenices cluster. The second line of work relates to the optimization of HPF. By targeting M dwarfs, HPF will take advantage of the large signal induced by an Earth-mass planet orbiting an M dwarf compared to the same planet orbiting an FGK star. Chapter 6 discusses a number of design trades and parameter optimizations undertaken in order to ensure the best sensitivity to Earth-mass planets. These subtopics include the optimization of the HPF resolution, bandpass, operating temperature, and vacuum phase holographic cross-disperser, as well as prediction of anticipated HPF performance, and the development of an HPF software simulator tool. In carrying out NIR detector tests for HPF, we have also tested an optical filter that selectively blocks long-wavelength thermal background radiation. This type of contamination is a perennial source of noise for NIR instruments, and typically forces these instruments to operate fully cryogenically. The complexity and cost of this approach may be avoided: for instruments operating in the H-band or bluer, the thermal background can be optically filtered, freeing the instrument to operate at warmer temperatures. Chapter 7 details our characterization and application of an interference filter that effectively blocks thermal background when used with a 1.7mum-cutoff HAWAII-2RG NIR detector array. By effectively filtering the thermal background with a single coated optic, this filter offers the potential for simple, cost-effective, warm-pupil NIR astronomical instruments, which can take advantage of the increasing availability of low-noise, high-efficiency NIR detectors.

Measurement of drug-target engagement in live cells by two-photon fluorescence anisotropy imaging.

PubMed

Vinegoni, Claudio; Fumene Feruglio, Paolo; Brand, Christian; Lee, Sungon; Nibbs, Antoinette E; Stapleton, Shawn; Shah, Sunil; Gryczynski, Ignacy; Reiner, Thomas; Mazitschek, Ralph; Weissleder, Ralph

2017-07-01

The ability to directly image and quantify drug-target engagement and drug distribution with subcellular resolution in live cells and whole organisms is a prerequisite to establishing accurate models of the kinetics and dynamics of drug action. Such methods would thus have far-reaching applications in drug development and molecular pharmacology. We recently presented one such technique based on fluorescence anisotropy, a spectroscopic method based on polarization light analysis and capable of measuring the binding interaction between molecules. Our technique allows the direct characterization of target engagement of fluorescently labeled drugs, using fluorophores with a fluorescence lifetime larger than the rotational correlation of the bound complex. Here we describe an optimized protocol for simultaneous dual-channel two-photon fluorescence anisotropy microscopy acquisition to perform drug-target measurements. We also provide the necessary software to implement stream processing to visualize images and to calculate quantitative parameters. The assembly and characterization part of the protocol can be implemented in 1 d. Sample preparation, characterization and imaging of drug binding can be completed in 2 d. Although currently adapted to an Olympus FV1000MPE microscope, the protocol can be extended to other commercial or custom-built microscopes.

Spectroscopic, Elemental and Thermal Analysis, and Positron Annihilation Studies on Ca(II), Sr(II), Ba(II), Pb(II), and Fe(III) Penicillin G Potassium Complexes

NASA Astrophysics Data System (ADS)

Refat, M. S.; Sharshara, T.

2015-11-01

The [Pb(Pin)2] · 3H2O, [M(Pin)(H2O)2(Cl)] · nH2O (M = SrII, CaII or BaII; n = 0-1), and [Fe(Pin)2(Cl)(H2O)] · H2O penicillin G potassium (Pin) complexes were synthesized and characterized using elemental analyses, molar conductivity, thermal analysis and electronic spectroscopy techniques. The positron annihilation lifetime (PAL) and Doppler broadening (DB) techniques have been employed to probe the defects and structural changes of Pin ligand and its complexes. The PAL and DB line-shape parameters were discussed in terms of the structure, molecular weight, ligand-metal molar ratio, and other properties of the Pin complexes.

Tip-enhanced Raman scattering (TERS) and high-resolution bio nano-analysis--a comparison.

PubMed

Deckert-Gaudig, Tanja; Deckert, Volker

2010-10-14

This perspective presents and assesses the development and capabilities of tip-enhanced Raman scattering (TERS) since its discovery in 2000. So far, this technique has proven to be valuable for studies of a variety of inorganic, organic and biochemical specimens. Due to its ability to provide chemical and topographic characterization in a single experiment at a sub-100 nm resolution, TERS has gained importance in super-resolution structural analysis. In this contribution the focus is set on applications with relevance in the biology and medical fields. The potential and challenges of this near-field technique are discussed with respect to state-of-the-art microscopic and spectroscopic imaging methods. Furthermore, possible ways to surpass current boundaries and an outlook to future projects are presented.

Imaging of Scleral Collagen Deformation Using Combined Confocal Raman Microspectroscopy and Polarized Light Microscopy Techniques.

PubMed

Chakraborty, Nilay; Wang, Mian; Solocinski, Jason; Kim, Wonsuk; Argento, Alan

2016-01-01

This work presents an optospectroscopic characterization technique for soft tissue microstructure using site-matched confocal Raman microspectroscopy and polarized light microscopy. Using the technique, the microstructure of soft tissue samples is directly observed by polarized light microscopy during loading while spatially correlated spectroscopic information is extracted from the same plane, verifying the orientation and arrangement of the collagen fibers. Results show the response and orientation of the collagen fiber arrangement in its native state as well as during tensile and compressive loadings in a porcine sclera model. An example is also given showing how the data can be used with a finite element program to estimate the strain in individual collagen fibers. The measurements demonstrate features that indicate microstructural reorganization and damage of the sclera's collagen fiber arrangement under loading. The site-matched confocal Raman microspectroscopic characterization of the tissue provides a qualitative measure to relate the change in fibrillar arrangement with possible chemical damage to the collagen microstructure. Tests and analyses presented here can potentially be used to determine the stress-strain behavior, and fiber reorganization of the collagen microstructure in soft tissue during viscoelastic response.

K[AsW{sub 2}O{sub 9}], the first member of the arsenate–tungsten bronze family: Synthesis, structure, spectroscopic and non-linear optical properties

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

Alekseev, Evgeny V., E-mail: e.alekseev@fz-juelich.de; Institut für Kristallographie, RWTH Aachen, Jägerstraße 17–19 D-52066 Aachen; Felbinger, Olivier

K[AsW{sub 2}O{sub 9}], prepared by high-temperature solid-state reaction, is the first member of the arsenate–tungsten bronze family. The structure of K[AsW{sub 2}O{sub 9}] is based on a 3-dimensional (3D) oxotungstate–arsenate framework with the non-centrosymmetric P2{sub 1}2{sub 1}2{sub 1} space group, a=4.9747(3) Å, b=9.1780(8) Å, c=16.681(2) Å. The material was characterized using X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Raman and infrared (IR) spectroscopic techniques. The results of DSC demonstrate that this phase is stable up to 1076 K. Second harmonic generation (SHG) measurements performed on a powder sample demonstrate noticeable (0.1 of LiIO{sub 3}) non-linear optical (NLO)more » activity. - Graphical abstract: K[AsW{sub 2}O{sub 9}], the first member of arsenate–tungsten bronze family exhibit new three dimensional structure type, significant thermal stability and NLO properties. Highlights: • K[AsW{sub 2}O{sub 9}], the first member of the arsenate–tungsten bronze family was synthesized with solid state reaction technique. • Structure of this phase was investigated with X-ray diffraction, IR and Raman spectroscopy and electron microscopy. • Thermal stability of the phase was determinate with DSC techniques. • NLO properties were investigated.« less

Intramolecular proton transfer boosts water oxidation catalyzed by a Ru complex

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

Matheu, Roc; Ertem, Mehmed Z.; Benet-Buchholz, J.

We introduce a new family of complexes with the general formula [Ru n(tda)(py)2] m+ (n = 2, m = 0, 1; n = 3, m = 1, 2 +; n = 4, m = 2, 3 2+), with tda 2– being [2,2':6',2"-terpyridine]-6,6"-dicarboxylate, including complex [Ru IV(OH)(tda-κ-N 3O)(py) 2] +, 4H +, which we find to be an impressive water oxidation catalyst, formed by hydroxo coordination to 3 2+ under basic conditions. The complexes are synthesized, isolated, and thoroughly characterized by analytical, spectroscopic (UV–vis, nuclear magnetic resonance, electron paramagnetic resonance), computational, and electrochemical techniques (cyclic voltammetry, differential pulse voltammetry, coulometry), includingmore » solid-state monocrystal X-ray diffraction analysis. In oxidation state IV, the Ru center is seven-coordinated and diamagnetic, whereas in oxidation state II, the complex has an unbonded dangling carboxylate and is six-coordinated while still diamagnetic. With oxidation state III, the coordination number is halfway between the coordination of oxidation states II and IV. Species generated in situ have also been characterized by spectroscopic, computational, and electrochemical techniques, together with the related species derived from a different degree of protonation and oxidation states. 4H + can be generated potentiometrically, or voltammetrically, from 3 2+, and both coexist in solution. While complex 3 2+ is not catalytically active, the catalytic performance of complex 4H + is characterized by the foot of the wave analysis, giving an impressive turnover frequency record of 8000 s –1 at pH 7.0 and 50,000 s –1 at pH 10.0. Density functional theory calculations provide a complete description of the water oxidation catalytic cycle of 4H +, manifesting the key functional role of the dangling carboxylate in lowering the activation free energies that lead to O–O bond formation.« less

A Multiscale Vibrational Spectroscopic Approach for Identification and Biochemical Characterization of Pollen

PubMed Central

Bağcıoğlu, Murat; Zimmermann, Boris; Kohler, Achim

2015-01-01

Background Analysis of pollen grains reveals valuable information on biology, ecology, forensics, climate change, insect migration, food sources and aeroallergens. Vibrational (infrared and Raman) spectroscopies offer chemical characterization of pollen via identifiable spectral features without any sample pretreatment. We have compared the level of chemical information that can be obtained by different multiscale vibrational spectroscopic techniques. Methodology Pollen from 15 different species of Pinales (conifers) were measured by seven infrared and Raman methodologies. In order to obtain infrared spectra, both reflectance and transmission measurements were performed on ground and intact pollen grains (bulk measurements), in addition, infrared spectra were obtained by microspectroscopy of multigrain and single pollen grain measurements. For Raman microspectroscopy measurements, spectra were obtained from the same pollen grains by focusing two different substructures of pollen grain. The spectral data from the seven methodologies were integrated into one data model by the Consensus Principal Component Analysis, in order to obtain the relations between the molecular signatures traced by different techniques. Results The vibrational spectroscopy enabled biochemical characterization of pollen and detection of phylogenetic variation. The spectral differences were clearly connected to specific chemical constituents, such as lipids, carbohydrates, carotenoids and sporopollenins. The extensive differences between pollen of Cedrus and the rest of Pinaceae family were unambiguously connected with molecular composition of sporopollenins in pollen grain wall, while pollen of Picea has apparently higher concentration of carotenoids than the rest of the family. It is shown that vibrational methodologies have great potential for systematic collection of data on ecosystems and that the obtained phylogenetic variation can be well explained by the biochemical composition of pollen. Out of the seven tested methodologies, the best taxonomical differentiation of pollen was obtained by infrared measurements on bulk samples, as well as by Raman microspectroscopy measurements of the corpus region of the pollen grain. Raman microspectroscopy measurements indicate that measurement area, as well as the depth of focus, can have crucial influence on the obtained data. PMID:26376486

Intramolecular proton transfer boosts water oxidation catalyzed by a Ru complex

DOE PAGES

Matheu, Roc; Ertem, Mehmed Z.; Benet-Buchholz, J.; ...

2015-07-30

We introduce a new family of complexes with the general formula [Ru n(tda)(py)2] m+ (n = 2, m = 0, 1; n = 3, m = 1, 2 +; n = 4, m = 2, 3 2+), with tda 2– being [2,2':6',2"-terpyridine]-6,6"-dicarboxylate, including complex [Ru IV(OH)(tda-κ-N 3O)(py) 2] +, 4H +, which we find to be an impressive water oxidation catalyst, formed by hydroxo coordination to 3 2+ under basic conditions. The complexes are synthesized, isolated, and thoroughly characterized by analytical, spectroscopic (UV–vis, nuclear magnetic resonance, electron paramagnetic resonance), computational, and electrochemical techniques (cyclic voltammetry, differential pulse voltammetry, coulometry), includingmore » solid-state monocrystal X-ray diffraction analysis. In oxidation state IV, the Ru center is seven-coordinated and diamagnetic, whereas in oxidation state II, the complex has an unbonded dangling carboxylate and is six-coordinated while still diamagnetic. With oxidation state III, the coordination number is halfway between the coordination of oxidation states II and IV. Species generated in situ have also been characterized by spectroscopic, computational, and electrochemical techniques, together with the related species derived from a different degree of protonation and oxidation states. 4H + can be generated potentiometrically, or voltammetrically, from 3 2+, and both coexist in solution. While complex 3 2+ is not catalytically active, the catalytic performance of complex 4H + is characterized by the foot of the wave analysis, giving an impressive turnover frequency record of 8000 s –1 at pH 7.0 and 50,000 s –1 at pH 10.0. Density functional theory calculations provide a complete description of the water oxidation catalytic cycle of 4H +, manifesting the key functional role of the dangling carboxylate in lowering the activation free energies that lead to O–O bond formation.« less

Application of a novel combination of near-infrared spectroscopy and a humidity-controlled 96-well plate to the characterization of the polymorphism of imidafenacin.

PubMed

Uchida, Hiroshi; Yoshinaga, Tokuji; Mori, Hirotoshi; Otsuka, Makoto

2010-11-01

This study aimed to apply a currently available chemometric near-infrared spectroscopy technique to the characterization of the polymorphic properties of drug candidates. The technique requires only small quantities of samples and is therefore applicable to drugs in the early stages of development. The combination of near-infrared spectroscopy and a patented 96-well plate divided into 32 individual, humidity-controlled, three-well compartments was used in the characterization of a hygroscopic drug, imidafenacin, which has two polymorphs and one pseudo-polymorph. Characterization was also conducted with powder X-ray diffraction and thermal analysis. The results were compared with those from routinely used conventional analyses. Both the microanalysis and conventional analysis successfully characterised the substance (transformation and relative stability among the two polymorphs and a pseudo-polymorph) depending on the storage conditions. Near-infrared spectroscopic analyses utilizing a humidity-controlled 96-well plate required only small amounts of the sample for characterization under the various conditions of relative humidity. Near-infrared microanalysis can be applied to polymorphic studies of small quantities of a drug candidate. The results also suggest that the method will predict the behaviors of a hygroscopic candidate in solid pharmaceutical preparations at the early stages of drug development. © 2010 The Authors. JPP © 2010 Royal Pharmaceutical Society of Great Britain.

Chemical mapping of pharmaceutical cocrystals using terahertz spectroscopic imaging.

PubMed

Charron, Danielle M; Ajito, Katsuhiro; Kim, Jae-Young; Ueno, Yuko

2013-02-19

Terahertz (THz) spectroscopic imaging is a promising technique for distinguishing pharmaceuticals of similar molecular composition but differing crystal structures. Physicochemical properties, for instance bioavailability, are manipulated by altering a drug's crystal structure through methods such as cocrystallization. Cocrystals are molecular complexes having crystal structures different from those of their pure components. A technique for identifying the two-dimensional distribution of these alternate forms is required. Here we present the first demonstration of THz spectroscopic imaging of cocrystals. THz spectra of caffeine-oxalic acid cocrystal measured at low temperature exhibit sharp peaks, enabling us to visualize the cocrystal distribution in nonuniform tablets. The cocrystal distribution was clearly identified using THz spectroscopic data, and the cocrystal concentration was calculated with 0.3-1.3% w/w error from the known total concentration. From this result, THz spectroscopy allows quantitative chemical mapping of cocrystals and offers researchers and drug developers a new analytical tool.

FAST CARS: Engineering a laser spectroscopic technique for rapid identification of bacterial spores

PubMed Central

Scully, M. O.; Kattawar, G. W.; Lucht, R. P.; Opatrný, T.; Pilloff, H.; Rebane, A.; Sokolov, A. V.; Zubairy, M. S.

2002-01-01

Airborne contaminants, e.g., bacterial spores, are usually analyzed by time-consuming microscopic, chemical, and biological assays. Current research into real-time laser spectroscopic detectors of such contaminants is based on e.g., resonance fluorescence. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. However, generating and using maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is challenging. In particular, the short dephasing times and rapid internal conversion rates are major obstacles. However, adiabatic fast passage techniques and the ability to generate combs of phase-coherent femtosecond pulses provide tools for the generation and utilization of maximal quantum coherence in large molecules and biopolymers. We call this technique FAST CARS (femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman spectroscopy), and the present article proposes and analyses ways in which it could be used to rapidly identify preselected molecules in real time. PMID:12177405

A novel pulse height analysis technique for nuclear spectroscopic and imaging systems

NASA Astrophysics Data System (ADS)

Tseng, H. H.; Wang, C. Y.; Chou, H. P.

2005-08-01

The proposed pulse height analysis technique is based on the constant and linear relationship between pulse width and pulse height generated from front-end electronics of nuclear spectroscopic and imaging systems. The present technique has successfully implemented into the sump water radiation monitoring system in a nuclear power plant. The radiation monitoring system uses a NaI(Tl) scintillator to detect radioactive nuclides of Radon daughters brought down by rain. The technique is also used for a nuclear medical imaging system. The system uses a position sensitive photomultiplier tube coupled with a scintillator. The proposed techniques has greatly simplified the electronic design and made the system a feasible one for potable applications.

Novel physical chemistry approaches in biophysical researches with advanced application of lasers: Detection and manipulation.

PubMed

Iwata, Koichi; Terazima, Masahide; Masuhara, Hiroshi

2018-02-01

Novel methodologies utilizing pulsed or intense CW irradiation obtained from lasers have a major impact on biological sciences. In this article, recent development in biophysical researches fully utilizing the laser irradiation is described for three topics, time-resolved fluorescence spectroscopy, time-resolved thermodynamics, and manipulation of the biological assemblies by intense laser irradiation. First, experimental techniques for time-resolved fluorescence spectroscopy are concisely explained in Section 2. As an example of the recent application of time-resolved fluorescence spectroscopy to biological systems, evaluation of the viscosity of lipid bilayer membranes is described. The results of the spectroscopic experiments strongly suggest the presence of heterogeneous membrane structure with two different viscosity values in liposomes formed by a single phospholipid. Section 3 covers the time-resolved thermodynamics. Thermodynamical properties are important to characterize biomolecules. However, measurement of these quantities for short-lived intermediate species has been impossible by traditional thermodynamical techniques. Recently, development of a spectroscopic method based on the transient grating method enables us to measure these quantities and also to elucidate reaction kinetics which cannot be detected by other spectroscopic methods. The principle of the measurements and applications to some protein reactions are reviewed. Manipulation and fabrication of supramolecues, amino acids, proteins, and living cells by intense laser irradiation are described in Section 4. Unconventional assembly, crystallization and growth, amyloid fibril formation, and living cell manipulation are achieved by CW laser trapping and femtosecond laser-induced cavitation bubbling. Their spatio-temporal controllability is opening a new avenue in the relevant molecular and bioscience research fields. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017. Published by Elsevier B.V.

Molecular dispersion spectroscopy – new capabilities in laser chemical sensing

PubMed Central

Nikodem, Michal; Wysocki, Gerard

2012-01-01

Laser spectroscopic techniques suitable for molecular dispersion sensing enable new applications and strategies in chemical detection. This paper discusses the current state-of-the art and provides an overview of recently developed chirped laser dispersion spectroscopy (CLaDS) based techniques. CLaDS and its derivatives allow for quantitative spectroscopy of trace-gases and enable new capabilities such as extended dynamic range of concentration measurements, high immunity to photodetected intensity fluctuations, or capability of direct processing of spectroscopic signals in optical domain. Several experimental configurations based on quantum cascade lasers and examples of molecular spectroscopic data are presented to demonstrate capabilities of molecular dispersion spectroscopy in the mid-infrared spectral region. PMID:22809459

Laser Spectroscopy for Atmospheric and Environmental Sensing

PubMed Central

Fiddler, Marc N.; Begashaw, Israel; Mickens, Matthew A.; Collingwood, Michael S.; Assefa, Zerihun; Bililign, Solomon

2009-01-01

Lasers and laser spectroscopic techniques have been extensively used in several applications since their advent, and the subject has been reviewed extensively in the last several decades. This review is focused on three areas of laser spectroscopic applications in atmospheric and environmental sensing; namely laser-induced fluorescence (LIF), cavity ring-down spectroscopy (CRDS), and photoluminescence (PL) techniques used in the detection of solids, liquids, aerosols, trace gases, and volatile organic compounds (VOCs). PMID:22303184

Autofluorescence spectroscopy for multimodal tissues characterization in colitis-associated cancer murine model

NASA Astrophysics Data System (ADS)

Dorez, Hugo; Sablong, Raphaël.; Canaple, Laurence; Saint-Jalmes, Hervé; Gaillard, Sophie; Moussata, Driffa; Beuf, Olivier

2015-07-01

The purpose of this research project is to assess mice colon wall, using three optical modalities (conventional endoscopy, confocal endomicroscopy and optical spectroscopy) and endoluminal MRI. The study is done in the context of inflammatory bowel disease and colorectal cancer that represent 13% of new cases of cancer, every year in western countries. An optical spectroscopic bench (autofluorescence and reflectance) was developed with a flexible fiber probe. This latter has been combined with a mini multi-purpose rigid endoscope and a confocal endomicroscope. The optical modalities were first used in vivo on SWISS mice. Then, a specific optical a phantom (containing two layers of distinct fluorophores) was developed in order to evaluate our two-channel spectroscopic probe as a basic depth-sensitive measurement tool. The preliminary results show the feasibility to combine such modalities in the same in vivo protocol. Conventional endoscopy is useful to depict inflammation along colon wall. Confocal endomicroscopy provides high-contrasted images of microvascularization. Measured optical spectra both depend on biochemical tissue content and layered structure of the medium. The light collected from one channel is not similar to the other, in terms of intensity and spectroscopic profile as the interaction with the medium observed volume is different. A comparative analysis of the spectra based on our in vitro model exhibits a strong correlation between simple index extracted from spectral data and two main phantom characteristics (fluorophore concentrations and superficial layer thickness). This work suggests that this technique could contribute to assess tissues alterations through autofluorescence spectroscopic measurement under endoscopy.

Synthesis and Characterization of Molybdenum Based Colloidal Particles.

PubMed

Moreno; Vidoni; Ovalles; Chaudret; Urbina; Krentzein

1998-11-15

The synthesis and characterization of molybdenum colloidal particles were evaluated using thermal and sonochemical methods and starting from different metal precursors, Mo(CO)6 and (NH4)2MoS4. The products were characterized by elemental analysis, spectroscopic (UV, FTIR), and surface analysis (XPS) techniques, as well as by transmission electron microscopy (TEM) for determining the particle sizes. Using Mo(CO)6 as metal source, particle sizes with an average diameter of 1.5 nm can be obtained using tert-amyl alcohol as solvent and tetrahydrothiophene as sulfurating ligand. The characterization of these particles showed that they are composed of molybdenum oxide MoO3. Using (NH4)2MoS4 as metal precursor, particles with average diameters of 4.7 and 2.5 nm were synthesized using thermal and sonochemical methods, respectively. The characterization of these particles showed them to be composed of molybdenum sulfide, MoS2. The sonochemical method proved to be the fastest and most convenient synthetic pathway of obtaining small colloidal particles at low temperatures and with control of the average size. Copyright 1998 Academic Press.

Multidisciplinary approach for the study of an Egyptian coffin (late 22nd/early 25th dynasty): combining imaging and spectroscopic techniques.

PubMed

Bracci, S; Caruso, O; Galeotti, M; Iannaccone, R; Magrini, D; Picchi, D; Pinna, D; Porcinai, S

2015-06-15

This paper demonstrates that an educated methodology based on both non-invasive and micro invasive techniques in a two-step approach is a powerful tool to characterize the materials and stratigraphies of an Egyptian coffin, which was restored several times. This coffin, belonging to a certain Mesiset, is now located at the Museo Civico Archeologico of Bologna (inventory number MCABo EG 1963). Scholars attributed it to the late 22nd/early 25th dynasty by stylistic comparison. The first step of the diagnostic approach applied imaging techniques on the whole surface in order to select measurements spots and to unveil both original and restored areas. Images and close microscopic examination of the polychrome surface allowed selecting representative areas to be investigated in situ by portable spectroscopic techniques: X-ray Fluorescence (XRF), Fiber Optic Reflectance Spectroscopy (FORS) and Fourier Transform Infrared spectroscopy (FTIR). After the analysis of the results coming from the first step, very few selected samples were taken to clarify the stratigraphy of the polychrome layers. The first step, based on the combination of imaging and spectroscopic techniques in a totally non-invasive modality, is quite unique in the literature on Egyptian coffins and enabled us to reveal many differences in the ground layer's composition and to identify a remarkable number of pigments in the original and restored areas. This work offered also a chance to check the limitations of the non-invasive approach applied on a complex case, namely the right localization of different materials in the stratigraphy and the identification of binding media. Indeed, to dissolve any remaining doubts on superimposed layers belonging to different interventions, it was necessary to sample few micro-fragments in some selected areas and analyze them prepared as cross-sections. The original ground layer is made of calcite, while the restored areas show the presence of either a mixture of calcite and silicates or a gypsum ground, overlapped by lead white. The original pigments were identified as orpiment, cinnabar and red clay, Egyptian blue and green copper based pigments. Some other pigments, such as white lead, Naples yellow, cerulean blue and azurite were only found in the restored areas. Copyright © 2015 Elsevier B.V. All rights reserved.

[Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

PubMed

Jiang, Zhi-quan; Hu, Ke-liang

2016-03-01

In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science.

Spectroscopic characterization of low dose rate brachytherapy sources

NASA Astrophysics Data System (ADS)

Beach, Stephen M.

The low dose rate (LDR) brachytherapy seeds employed in permanent radioactive-source implant treatments usually use one of two radionuclides, 125I or 103Pd. The theoretically expected source spectroscopic output from these sources can be obtained via Monte Carlo calculation based upon seed dimensions and materials as well as the bare-source photon emissions for that specific radionuclide. However the discrepancies resulting from inconsistent manufacturing of sources in comparison to each other within model groups and simplified Monte Carlo calculational geometries ultimately result in undesirably large uncertainties in the Monte Carlo calculated values. This dissertation describes experimentally attained spectroscopic outputs of the clinically used brachytherapy sources in air and in liquid water. Such knowledge can then be applied to characterize these sources by a more fundamental and metro logically-pure classification, that of energy-based dosimetry. The spectroscopic results contained within this dissertation can be utilized in the verification and benchmarking of Monte Carlo calculational models of these brachytherapy sources. This body of work was undertaken to establish a usable spectroscopy system and analysis methods for the meaningful study of LDR brachytherapy seeds. The development of a correction algorithm and the analysis of the resultant spectroscopic measurements are presented. The characterization of the spectrometer and the subsequent deconvolution of the measured spectrum to obtain the true spectrum free of any perturbations caused by the spectrometer itself is an important contribution of this work. The approach of spectroscopic deconvolution that was applied in this work is derived in detail and it is applied to the physical measurements. In addition, the spectroscopically based analogs to the LDR dosimetry parameters that are currently employed are detailed, as well as the development of the theory and measurement methods to arrive at these analogs. Several dosimetrically-relevant water-equivalent plastics were also investigated for their transmission properties within a liquid water environment, as well as in air. The framework for the accurate spectrometry of LDR sources is established as a result of this dissertation work. In addition to the measurement and analysis methods, this work presents the basic measured spectroscopic characteristics of each LDR seed currently in use in the clinic today.

Customizing model membranes and samples for NMR spectroscopic studies of complex membrane proteins.

PubMed

Sanders, C R; Oxenoid, K

2000-11-23

Both solution and solid state nuclear magnetic resonance (NMR) techniques for structural determination are advancing rapidly such that it is possible to contemplate bringing these techniques to bear upon integral membrane proteins having multiple transmembrane segments. This review outlines existing and emerging options for model membrane media for use in such studies and surveys the special considerations which must be taken into account when preparing larger membrane proteins for NMR spectroscopic studies.

Gold(I) NHC-based homo- and heterobimetallic complexes: synthesis, characterization and evaluation as potential anticancer agents.

PubMed

Bertrand, Benoît; Citta, Anna; Franken, Inge L; Picquet, Michel; Folda, Alessandra; Scalcon, Valeria; Rigobello, Maria Pia; Le Gendre, Pierre; Casini, Angela; Bodio, Ewen

2015-09-01

While N-heterocyclic carbenes (NHC) are ubiquitous ligands in catalysis for organic or industrial syntheses, their potential to form transition metal complexes for medicinal applications has still to be exploited. Within this frame, we synthesized new homo- and heterobimetallic complexes based on the Au(I)-NHC scaffold. The compounds were synthesized via a microwave-assisted method developed in our laboratories using Au(I)-NHC complexes carrying a pentafluorophenol ester moiety and another Au(I) phosphane complex or a bipyridine ligand bearing a pendant amine function. Thus, we developed two different methods to prepare homo- and heterobimetallic complexes (Au(I)/Au(I) or Au(I)/Cu(II), Au(I)/Ru(II), respectively). All the compounds were fully characterized by several spectroscopic techniques including far infrared, and were tested for their antiproliferative effects in a series of human cancer cells. They showed moderate anticancer properties. Their toxic effects were also studied ex vivo using the precision-cut tissue slices (PCTS) technique and initial results concerning their reactivity with the seleno-enzyme thioredoxin reductase were obtained.

1-(4-(6-Fluorobenzo [d] isoxazol-3-yl) piperidin-1-yl)-2-(4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl) ethanone: Synthesis, spectroscopic characterization, Hirshfeld surface analysis, cytotoxic studies and docking studies

NASA Astrophysics Data System (ADS)

Govindhan, M.; Viswanathan, V.; Karthikeyan, S.; Subramanian, K.; Velmurugan, D.

2017-08-01

Compound 1-(4-(6-fluorobenzo[d] isoxazol-3-yl) piperidin-1-yl)-2-(4-(hydroxymethyl)-1H-1, 2,3-triazol-1-yl) ethanone was synthesized in good yield by using click chemistry approach with 2-azido-1-(4-(6-flurobenzo[d]isooxazol-3-yl)piperidin-1-yl)ethanone as a starting material. The synthesized compound was characterized using IR, NMR and MS studies. Thermal stability of the compound was analyzed by using TGA and DSC technique. The single crystal XRD analysis was taken part, to confirm the structure of the compound. The intercontacts in the crystal structure are analyzed using Hirshfeld surfaces computational method. Cytotoxicity of the synthesized compound was evaluated and the results were reported. The binding analysis carried out between the newly synthesized molecule with human serum albumin using fluorescence spectroscopy technique to understand the pharmacokinetics nature of the compound for further biological application. The molecular docking studies were evaluated for the compound to elucidate insights of new molecules in carrier protein.

High-pressure spectroscopic measurement on diffusion with a diamond-anvil cell

NASA Astrophysics Data System (ADS)

Aoki, K.; Katoh, Eriko; Yamawaki, H.; Fujihisa, H.; Sakashita, M.

2003-04-01

We report a diamond-anvil-cell (DAC) technique developed for spectroscopic measurement on the diffusion process in molecular solids at high pressure. The diffusion processes of atoms, molecules, or their ionic species are investigated for a bilayer specimen by measuring the variation of infrared vibrational spectra with time. The experimental procedures for the protonic and molecular diffusion measurements on ice at 400 K and 10.2 GPa are presented as an example study. The in situ spectroscopic technique with a DAC significantly extends the pressure range accessible for diffusion measurement. The diffusion process at a rate of 10-16-10-14 m2/s can currently be observed at temperatures of 300-600 K and pressures up to several tens of gigaPascals.

Synthesis and structural characterization of Co2+ ions doped ZnO nanopowders by solid state reaction through sonication

NASA Astrophysics Data System (ADS)

Babu, B.; Rama Krishna, Ch.; Venkata Reddy, Ch.; Pushpa Manjari, V.; Ravikumar, R. V. S. S. N.

2013-05-01

Cobalt ions doped zinc oxide nanopowder was prepared at room temperature by a novel and simple one step solid-state reaction method through sonication in the presence of a suitable surfactant Sodium Lauryl Sulphate (SLS). The prepared powder was characterized by various spectroscopic techniques. Powder XRD data revealed that the crystal structure belongs to hexagonal and its average crystallite size was evaluated. From optical absorption data, crystal fields (Dq), inter-electronic repulsion parameters (B, C) were evaluated. By correlating optical and EPR spectral data, the site symmetry of Co2+ ion in the host lattice was determined as octahedral. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. The CIE chromaticity coordinates are also evaluated from the emission spectrum. FT-IR spectra showed the characteristic vibrational bands of Znsbnd O.

Characterization of the infrared spectra of serum from patients with multiple myeloma

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

Plotnikova, L., E-mail: ljusja@mail.ru; Nosenko, T.; Uspenskaya, M., E-mail: mv-uspenskaya@mail.ru

Multiple myeloma (MM) accounts for about 1% of all types of cancers. MM is characterized by the proliferation of a single clone of plasma cells, which may produce and secrete a homogeneous monoclonal immunoglobulin. The monoclonal immunoglobulin is commonly referred to as an M protein. The M protein acts as a serological “tumor” marker that is useful for diagnosis and disease monitoring. The electrophoretic pattern reveals the M-protein in 80% of MM patients as a single peak or localized band. In our study we applied a combination of high-resolution agarose gel protein electrophoresis (PEL), spectroscopic techniques and thermal analysis tomore » identify the key differences in protein composition, protein structure and their thermal behavior for the samples obtained from the serum of MM patients and healthy donors.« less

Vibrational spectroscopy reveals the initial steps of biological hydrogen evolution.

PubMed

Katz, S; Noth, J; Horch, M; Shafaat, H S; Happe, T; Hildebrandt, P; Zebger, I

2016-11-01

[FeFe] hydrogenases are biocatalytic model systems for the exploitation and investigation of catalytic hydrogen evolution. Here, we used vibrational spectroscopic techniques to characterize, in detail, redox transformations of the [FeFe] and [4Fe4S] sub-sites of the catalytic centre (H-cluster) in a monomeric [FeFe] hydrogenase. Through the application of low-temperature resonance Raman spectroscopy, we discovered a novel metastable intermediate that is characterized by an oxidized [Fe I Fe II ] centre and a reduced [4Fe4S] 1+ cluster. Based on this unusual configuration, this species is assigned to the first, deprotonated H-cluster intermediate of the [FeFe] hydrogenase catalytic cycle. Providing insights into the sequence of initial reaction steps, the identification of this species represents a key finding towards the mechanistic understanding of biological hydrogen evolution.

Synthesis and characterization of multifunctional coordination polymer of the type [CuxNi1-x(dedb)·2H2O]n

NASA Astrophysics Data System (ADS)

Singh, Deepshikha; Kushwaha, Anita; Banerjee, A.; Prasad, R. L.

2015-07-01

New series of multifunctional homometallic and heterobimetallic coordination polymers of the type [CuxNi1-x(dedb)·2H2O]n {where dedb = dianion of 2,5-dichloro-3,6-bis(ethylamino)-1,4-benzoquinone (1); x = 1, (2); 0 (3); 0.5 (4); 0.25 (5); 0.125 (6); 0.0625 (7) and n = degree of polymerization} have been synthesized and characterized by Powder X-ray diffraction, IR, UV-visible and ESR spectroscopic techniques. Variable temperature susceptibility measurement indicates presence of strong ferromagnetic interaction. The effects of copper doping on thermal, magnetic and conducting properties of these polymers have been investigated in this communication. A rare co-existence of ferromagnetism as well as electrical conductivity has been observed in these polymers.

Self-assembly of a tetrahedral 58-nuclear barium vanadium oxide cluster.

PubMed

Kastner, Katharina; Puscher, Bianka; Streb, Carsten

2013-01-07

We report the synthesis and characterization of a molecular barium vanadium oxide cluster featuring high nuclearity and high symmetry. The tetrameric, 2.3 nm cluster H(5)[Ba(10)(NMP)(14)(H(2)O)(8)[V(12)O(33)](4)Br] is based on a bromide-centred, octahedral barium scaffold which is capped by four previously unknown [V(12)O(33)](6-) clusters in a tetrahedral fashion. The compound represents the largest polyoxovanadate-based heterometallic cluster known to date. The cluster is formed in organic solution and it is suggested that the bulky N-methyl-2-pyrrolidone (NMP) solvent ligands allow the isolation of this giant molecule and prevent further condensation to a solid-state metal oxide. The cluster is fully characterized using single-crystal XRD, elemental analysis, ESI mass spectrometry and other spectroscopic techniques.

Performance-Enhanced Bolometric Terahertz Detectors Based on V2O5 for 15 to 30 THz

NASA Astrophysics Data System (ADS)

Sumesh, M. A.; Karanth, S. P.; Thomas, Beno; Rao, G. M.; Viswanathan, M.; Chakraborty, P.; Rao, G. N.

2017-02-01

Terahertz (THz) radiation perception using uncooled detectors are gaining importance due to the increasing demands in the areas of military, space, and industrial, medical, and surveillance applications. In spite of the efforts of researchers to fill the THz gap, there exists a need for detectors in the range between 15 THz and 30 THz. In this paper, we discuss the development of bolometric detectors whose performance is enhanced by an optical immersion technique and their characterization in the aforesaid range of frequencies. These detectors are characterized by high specific detectivity ( D*) of 1.28 × 109 cmHz1/2 W-1 and high radiometric resolution (noise-equivalent temperature difference = 26 mK) and are fast enough for bolometric detectors (time constant = 1.7 ms), which make them suitable for spectroscopic and imaging applications.

Microscopy with slow electrons: from LEEM to XPEEM

ScienceCinema

Bauer, Ernst [Arizona State University, Phoenix, Arizona, United States

2017-12-09

The short penetration and escape depth of electrons with energies below 1 keV make them ideally suited for the study of surfaces and ultrathin films. The combination of the low energy electrons and the high lateral resolution of a microscope produces a powerful method for the characterization of nanostructures on bulk samples, in particular if the microscope is equipped with an imaging energy filter and connected to a synchrotron radiation source. Comprehensive characterization by imaging, diffraction, and spectroscope of the structural, chemical, and magnetic properties is then possible. The Talk will describe the various imaging techniques in using reflected and emitted electrons in low-energy electron microscopy (LEEM) and x-ray photoemission electron microscopy (XPEEM), with an emphasis on magnetic materials with spin-polarized LEEM and x-ray magnetic circular dichroism PEEM. The talk with end with an outlook on future possibilities.

Synthesis and characterization β-ketoamine ligands

NASA Astrophysics Data System (ADS)

Zaid, Nurzati Amani Mohamed; Hassan, Nur Hasyareeda; Karim, Nurul Huda Abd

2018-04-01

β-ketoamine ligands are important members of heterodonor ligand because of their ease of preparation and modification of both steric and/or electronic effects. Complexes with β-ketoamine has received much less attention and there has been no study about this complex with β-ketoamine in ionic liquid reported. Two type of β-ketoamine ligands which are 4-amino-3-pentene-2-onato (A) and 3-amino-2-butenoic acid methyl ester (B) have been synthesized in this work. The resulting compound formed was characterized using standard spectroscopic and structural techniques which includes 1H and 13C, NMR spectroscopy and FTIR spectroscopy. The 1H and 13C NMR spectrum displayed all the expected signals with correct integration and multiplicity. And it is proved that there are some differences between two ligands as observed in NMR and FTIR spectrum.

Inhibitory effect of trichodermanone C, a sorbicillinoid produced by Trichoderma citrinoviride associated to the green alga Cladophora sp., on nitrite production in LPS-stimulated macrophages.

PubMed

Marra, Roberta; Nicoletti, Rosario; Pagano, Ester; DellaGreca, Marina; Salvatore, Maria Michela; Borrelli, Francesca; Lombardi, Nadia; Vinale, Francesco; Woo, Sheridan L; Andolfi, Anna

2018-05-31

From the green alga Cladophora sp. collected in Italy, the marine fungal strain A12 of Trichoderma citrinoviride was isolated, identified and characterized. LC-MS qTOF analysis was applied to perform a metabolic profile of the fungal culture. Chromatographic techniques and spectroscopic methods were used to isolate and characterize the major secondary metabolites produced by this strain in liquid culture. In particular, four known sorbicillinoids (trichodermanone C, spirosorbicillinol A, vertinolide and sorbicillin) were purified and identified, together with 2-phenylethanol and tyrosol. Moreover, metabolomic analysis allowed to detect small amounts of trichodimerol, rezishanone A, 2',3'-dihydrosorbicillin and bisvertinol. For the first time a significant inhibitory effect on nitrite levels has been shown for trichodermanone C in lipopolysaccharide-stimulated J774A.1 macrophages.

Synthesis and spectroscopic characterization of gallic acid and some of its azo complexes

NASA Astrophysics Data System (ADS)

Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

2012-04-01

A series of gallic acid and azo gallic acid complexes were prepared and characterized by elemental analysis, IR, electronic spectra and magnetic susceptibility. The complexes were of different geometries: Octahedral, Tetrahedral and Square Planar. ESR was studied for copper complexes. All of the prepared complexes were of isotropic nature. The thermal analyses of the complexes were studied by DTA and DSC techniques. The thermodynamic parameters and the thermal transitions, such as glass transitions, crystallization and melting temperatures for some ligands and their complexes were evaluated and discussed. The entropy change values, ΔS#, showed that the transition states are more ordered than the reacting complexes. The biological activities of some ligands and their complexes are tested against Gram positive and Gram negative bacteria. The results showed that some complexes have a well considerable activity against different organisms.

Application of Mössbauer Spectroscopy in Earth Sciences

NASA Astrophysics Data System (ADS)

Vandenberghe, Robert E.; De Grave, Eddy

Iron being the fourth most abundant element in the earth crust, 57Fe Mössbauer spectroscopy has become a suitable additional technique for the characterization of all kind of soil materials and minerals. However, for that purpose a good knowledge of the spectral behavior of the various minerals is indispensable. In this chapter a review of the most important soil materials and rock-forming minerals is presented. It starts with a description of the Mössbauer spectroscopic features of the iron oxides and hydroxides, which are essentially present in soils and sediments. Further, the Mössbauer spectra from sulfides, sulfates and carbonates are briefly considered. Finally, the Mössbauer features of the typical and most common silicate and phosphate minerals are reported. The chapter ends with some typical examples, illustrating the use and power of Mössbauer spectroscopy in the characterization of minerals.

Raman spectroscopic characterization of urine of normal and cervical cancer subjects

NASA Astrophysics Data System (ADS)

Pappu, Raja; Prakasarao, Aruna; Dornadula, Koteeswaran; Singaravelu, Ganesan

2017-02-01

Cervical cancer is the fourth most common malignancy in female worldwide; the present method for diagnosis is the biopsy, Pap smear, colposcopy etc. To overcome the drawbacks of diagnosis an alternative technique is required, optical spectroscopy is a new technique where the discrimination of normal and cancer subjects provides valuable potential information in the diagnostic oncology at an early stage. Raman peaks in the spectra suggest interesting differences in various bio molecules. In this regard, non invasive optical detection of cervical cancer using urine samples by Raman Spectroscopy combined with LDA diagnostic algorithm yields an accuracy of 100% for original and cross validated group respectively. As the results were appreciable it is necessary to carry out the analysis for more number of samples to explore the facts hidden at different stages during the development of cervical cancer.

A One-Pot Synthesis of m-Terphenyls: A Guided Exploration of Reaction Chemistry, Chromatography, and Spectroscopy. A Miniproject for the Advanced Organic Chemistry Laboratory

NASA Astrophysics Data System (ADS)

Anam, Kishorekumar T.; Curtis, Michael P.; Irfan, Muhammad J.; Johnson, Michael P.; Royer, Andrew P.; Shahmohammadi, Kianor; Vinod, Thottumkara K.

2002-05-01

This four-week project-based laboratory exercise, developed for advanced organic chemistry students, involves a one-pot synthesis of m-terphenyls. Chemistry of aryl diazonium salts and Grignard reagents and reactivity of aryne intermediates toward nucleophilic reagents form the reaction chemistry basis for the project. The project exposes students to a number of important laboratory techniques (thin-layer chromatography, gas chromatography-mass spectrometry, and column chromatography) for monitoring reaction progress and product isolation. A variety of spectroscopic techniques, including IR, 1H NMR, 13C NMR, and attached proton test are used for product characterization. Students are also introduced to a useful empirical relationship to help predict (with considerable accuracy) the 13C chemical shift values of carbon atoms of substituted benzenes.

Optical, dielectric and morphological studies of sol-gel derived nanocrystalline TiO2 films.

PubMed

Vishwas, M; Sharma, Sudhir Kumar; Narasimha Rao, K; Mohan, S; Gowda, K V Arjuna; Chakradhar, R P S

2009-10-15

Nanocrystalline TiO(2) films have been synthesized on glass and silicon substrates by sol-gel technique. The films have been characterized with optical reflectance/transmittance in the wavelength range 300-1000 nm and the optical constants (n, k) were estimated by using envelope technique as well as spectroscopic ellipsometry. Morphological studies have been carried out using atomic force microscope (AFM). Metal-Oxide-Silicon (MOS) capacitor was fabricated using conducting coating on TiO(2) film deposited on silicon. The C-V measurements show that the film annealed at 300 degrees C has a dielectric constant of 19.80. The high percentage of transmittance, low surface roughness and high dielectric constant suggests that it can be used as an efficient anti-reflection coating on silicon and other optical coating applications and also as a MOS capacitor.

Noise analysis for CCD-based ultraviolet and visible spectrophotometry.

PubMed

Davenport, John J; Hodgkinson, Jane; Saffell, John R; Tatam, Ralph P

2015-09-20

We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a deuterium UV/Vis lamp and UV and visible LEDs. Common noise phenomena include source fluctuation noise, photoresponse nonuniformity, dark current noise, fixed pattern noise, and read noise. These were identified and characterized by varying light source, spectrometer settings, or temperature. A number of noise-limiting techniques are proposed, demonstrating a best-case spectroscopic noise equivalent absorbance of 3.5×10(-4)  AU for the AvaSpec-3648 and 5.6×10(-4)  AU for the Ocean Optics S2000 over a 30 s integration period. These techniques can be used on other CCD spectrometers to optimize performance.

NASA's Optical Measurement Program 2014 H.

NASA Astrophysics Data System (ADS)

Cowardin, H.; Lederer, S.; Stansbery, G.; Seitzer, P.; Buckalew, B.; Abercromby, K.; Barker, E.

2014-09-01

The Optical Measurements Group (OMG) within the NASA Orbital Debris Program Office (ODPO) addresses U.S. National Space Policy goals by monitoring and characterizing debris. Since 2001, the OMG has used the Michigan Orbital Debris Survey Telescope (MODEST) at Cerro Tololo Inter-American Observatory (CTIO) in Chile for general orbital debris survey. The 0.6-m Schmidt MODEST provides calibrated astronomical data of GEO targets, both catalogued and uncatalogued debris, with excellent image quality. The data are utilized by the ODPO modeling group and are included in the Orbital Debris Engineering Model (ORDEM) v. 3.0. MODEST and the CTIO/SMARTS (Small and Moderate Aperture Research Telescope System)0.9 m both acquire filter photometric data, as well as synchronously observing targets in selected optical filters. This information provides data used in material composition studies as well as longer orbital arc data on the same target, without time delay or bias from a rotating, tumbling, or spinning target. NASA, in collaboration with the University of Michigan, began using the twin 6.5-m Magellan telescopes at Las Campanas Observatory in Chile for deep imaging (Baade) and spectroscopic data (Clay) in 2011. Through the data acquired on Baade, debris have been detected that are ~3 magnitudes fainter than detections with MODEST, while the data from Clay provide better resolved information used in material characterization analyses via selected bandpasses. To better characterize and model optical data, the Optical Measurements Center (OMC) at NASA/JSC has been in operation since 2005, resulting in a database of comparison laboratory data. The OMC is designed to emulate illumination conditions in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. Lastly, the OMG is building the Meter Class Autonomous Telescope (MCAT) at Ascension Island. The 1.3-m telescope is designed to observe GEO and LEO targets, using a modified Ritchey-Chrétien configuration on a double horseshoe equatorial mount to allow tracking objects at LEO rates through the domes keyhole at zenith. Through the data collection techniques employed at these unique facilities, NASAs ODPO has developed a multi-faceted approach to characterize the orbital debris risk to satellites in various altitudes and provide material characterization of debris via photometric and spectroscopic measurements. Ultimately, the data are used in conjunction with in-situ and radar measurements to provide accurate data for models of our space environment and service spacecraft risk assessment.

NASA's Optical Measurement Program 2014

NASA Technical Reports Server (NTRS)

Cowardin, H.; Lederer, S.; Stansbery, G.; Seitzer, P.; Buckalew, B.; Abercromby, K.; Barker, E.

2014-01-01

The Optical Measurements Group (OMG) within the NASA Orbital Debris Program Office (ODPO) addresses U.S. National Space Policy goals by monitoring and characterizing debris. Since 2001, the OMG has used the Michigan Orbital Debris Survey Telescope (MODEST) at Cerro Tololo Inter-American Observatory (CTIO) in Chile for general orbital debris survey. The 0.6-m Schmidt MODEST provides calibrated astronomical data of GEO targets, both catalogued and uncatalogued debris, with excellent image quality. The data are utilized by the ODPO modeling group and are included in the Orbital Debris Engineering Model (ORDEM) v. 3.0. MODEST and the CTIO/SMARTS (Small and Moderate Aperture Research Telescope System) 0.9 m both acquire filter photometric data, as well as synchronously observing targets in selected optical filters. This information provides data used in material composition studies as well as longer orbital arc data on the same target, without time delay or bias from a rotating, tumbling, or spinning target. NASA, in collaboration with the University of Michigan, began using the twin 6.5-m Magellan telescopes at Las Campanas Observatory in Chile for deep imaging (Baade) and spectroscopic data (Clay) in 2011. Through the data acquired on Baade, debris have been detected that are 3 magnitudes fainter than detections with MODEST, while the data from Clay provide better resolved information used in material characterization analyses via selected bandpasses. To better characterize and model optical data, the Optical Measurements Center (OMC) at NASA/JSC has been in operation since 2005, resulting in a database of comparison laboratory data. The OMC is designed to emulate illumination conditions in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. Lastly, the OMG is building the Meter Class Autonomous Telescope (MCAT) at Ascension Island. The 1.3-m telescope is designed to observe GEO and LEO targets, using a modified Ritchey-Chrétien configuration on a double horseshoe equatorial mount to allow tracking objects at LEO rates through the dome's keyhole at zenith. Through the data collection techniques employed at these unique facilities, NASA's ODPO has developed a multi-faceted approach to characterize the orbital debris risk to satellites in various altitudes and provide material characterization of debris via photometric and spectroscopic measurements. Ultimately, the data are used in conjunction with in-situ and radar measurements to provide accurate data for models of our space environment and service spacecraft risk assessment.

NASA's Optical Measurement Program 2014

NASA Technical Reports Server (NTRS)

Cowardin, H.; Lederer, S. M.; Stansbery, G.; Seitzer, P.; Buckalew, B.; Abercromby, K.; Barker, E.

2014-01-01

The Optical Measurements Group (OMG) within the NASA Orbital Debris Program Office (ODPO) addresses U.S. National Space Policy goals by monitoring and characterizing debris. Since 2001, the OMG has used the Michigan Orbital Debris Survey Telescope (MODEST) at Cerro Tololo Inter-American Observatory (CTIO) in Chile for general orbital debris surveys. The 0.6-m Schmidt MODEST provides calibrated astronomical data of GEO targets, both catalogued and uncatalogued debris, with excellent image quality. The data are utilized by the ODPO modeling group and are included in the Orbital Debris Engineering Model (ORDEM) v. 3.0. MODEST and the CTIO/SMARTS (Small and Moderate Aperture Research Telescope System) 0.9 m are both employed to acquire filter photometry data as well as synchronously observe targets in selected optical filters. Obtaining data synchronously yields data for material composition studies as well as longer orbital arc data on the same target without time delay or bias from a rotating, tumbling, or spinning target. Observations of GEO orbital debris using the twin 6.5-m Magellan telescopes at Las Campanas Observatory in Chile for deep imaging (Baade) and spectroscopic data (Clay) began in 2011. Through the data acquired on Baade, debris has been detected that reaches approx. 3 magnitudes fainter than detections with MODEST, while the spectral data from Clay provide better resolved information used in material characterization analyses. To better characterize and model optical data, the Optical Measurements Center (OMC) at NASA/JSC has been in operation since 2005, resulting in a database of comparison laboratory data. The OMC is designed to emulate illumination conditions in space using equipment and techniques that parallel telescopic observations and sourcetarget- sensor orientations. Lastly, the OMG is building the Meter Class Autonomous Telescope (MCAT) at Ascension Island. The 1.3-m telescope is designed to observe GEO and LEO targets, using a modified Ritchey-Chrétien configuration on a double horseshoe equatorial mount to allow tracking objects at LEO rates through the dome's keyhole at zenith. Through the data collection techniques employed at these unique facilities, NASA's ODPO has developed a multifaceted approach to characterize the orbital debris risk to satellites in various altitudes and provide insight leading toward material characterization of debris via photometric and spectroscopic measurements. Ultimately, the data are used in conjunction with in-situ and radar measurements to provide accurate data for models of our space environment and for facilitating spacecraft risk assessment.

One-step Multiple Component Isolation from the Oil of Crinitaria tatarica (Less.) Sojak by Preparative Capillary Gas Chromatography with Characterization by Spectroscopic and Spectrometric Techniques and Evaluation of Biological Activity

DTIC Science & Technology

2012-01-01

tatarica oil in n-hexane/diethyl ether (8:2, v/v) were subsequently tested against Colletotrichum spp. and Rf Figure 4. Growth inhibition of Botrytis cinerea ...activity at 3.0 and 30 M and inhibited the growth of B. cinerea by 58.7 and 52.8%, respectively, after 48-h exposure (Fig. 4) and no activ- ity was...collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 2012 2. REPORT TYPE 3. DATES COVERED 00-00

Thiourea based novel chromogenic sensor for selective detection of fluoride and cyanide anions in organic and aqueous media.

PubMed

Kumar, Vinod; Kaushik, M P; Srivastava, A K; Pratap, Ajay; Thiruvenkatam, V; Row, T N Guru

2010-03-17

Novel chromogenic thiourea based sensors 4,4'-bis-[3-(4-nitrophenyl) thiourea] diphenyl ether 1 and 4,4'-bis-[3-(4-nitrophenyl) thiourea] diphenyl methane 2 having nitrophenyl group as signaling unit have been synthesized and characterized by spectroscopic techniques and X-ray crystallography. The both sensors show visual detection, UV-vis and NMR spectral changes in presence of fluoride and cyanide anions in organic solvent as well as in aqueous medium. The absorption spectra indicated the formation of complex between host and guest is in 1:2 stoichiometric ratios. Copyright 2010 Elsevier B.V. All rights reserved.

Fluorescence Spectroscopy for the Monitoring of Food Processes.

PubMed

Ahmad, Muhammad Haseeb; Sahar, Amna; Hitzmann, Bernd

Different analytical techniques have been used to examine the complexity of food samples. Among them, fluorescence spectroscopy cannot be ignored in developing rapid and non-invasive analytical methodologies. It is one of the most sensitive spectroscopic approaches employed in identification, classification, authentication, quantification, and optimization of different parameters during food handling, processing, and storage and uses different chemometric tools. Chemometrics helps to retrieve useful information from spectral data utilized in the characterization of food samples. This contribution discusses in detail the potential of fluorescence spectroscopy of different foods, such as dairy, meat, fish, eggs, edible oil, cereals, fruit, vegetables, etc., for qualitative and quantitative analysis with different chemometric approaches.

Dual exposure, two-photon, conformal phasemask lithography for three dimensional silicon inverse woodpile photonic crystals

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

Shir, Daniel J.; Nelson, Erik C.; Chanda, Debashis

2010-01-01

The authors describe the fabrication and characterization of three dimensional silicon inverse woodpile photonic crystals. A dual exposure, two-photon, conformal phasemask technique is used to create high quality polymer woodpile structures over large areas with geometries that quantitatively match expectations based on optical simulations. Depositing silicon into these templates followed by the removal of the polymer results in silicon inverse woodpile photonic crystals for which calculations indicate a wide, complete photonic bandgap over a range of structural fill fractions. Spectroscopic measurements of normal incidence reflection from both the polymer and siliconphotonic crystals reveal good optical properties.

Inclusion compound of vitamin B6 in β-CD. Physico-chemical and structural investigations

NASA Astrophysics Data System (ADS)

Borodi, Gheorghe; Kacso, Irina; Farcaş, Sorin I.; Bratu, Ioan

2009-08-01

Structural and physico-chemical characterization of supramolecular assembly of vitamin B6 with β-cyclodextrin (β-CD) prepared by different methods (kneading, co-precipitation and freeze-drying) has been performed by using several spectroscopic techniques (FTIR, 1H NMR, UV-Vis), powder X-ray diffraction and DSC in order to evidence the inclusion compound formation. An analysis of the chemical shifts observed in the 1H-NMR spectra and of the vibrational frequency shifts led to the tentative conclusion that the vitamin B6 probably enters the cyclodextrin torus when forming the β-CD-vitamin B6 inclusion complex.

Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations

NASA Astrophysics Data System (ADS)

Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Asiri, Abdullah M.; Kurt, Mustafa

2014-01-01

The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H⋯O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed.

RECONSTRUCTING REDSHIFT DISTRIBUTIONS WITH CROSS-CORRELATIONS: TESTS AND AN OPTIMIZED RECIPE

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

Matthews, Daniel J.; Newman, Jeffrey A., E-mail: djm70@pitt.ed, E-mail: janewman@pitt.ed

2010-09-20

Many of the cosmological tests to be performed by planned dark energy experiments will require extremely well-characterized photometric redshift measurements. Current estimates for cosmic shear are that the true mean redshift of the objects in each photo-z bin must be known to better than 0.002(1 + z), and the width of the bin must be known to {approx}0.003(1 + z) if errors in cosmological measurements are not to be degraded significantly. A conventional approach is to calibrate these photometric redshifts with large sets of spectroscopic redshifts. However, at the depths probed by Stage III surveys (such as DES), let alonemore » Stage IV (LSST, JDEM, and Euclid), existing large redshift samples have all been highly (25%-60%) incomplete, with a strong dependence of success rate on both redshift and galaxy properties. A powerful alternative approach is to exploit the clustering of galaxies to perform photometric redshift calibrations. Measuring the two-point angular cross-correlation between objects in some photometric redshift bin and objects with known spectroscopic redshift, as a function of the spectroscopic z, allows the true redshift distribution of a photometric sample to be reconstructed in detail, even if it includes objects too faint for spectroscopy or if spectroscopic samples are highly incomplete. We test this technique using mock DEEP2 Galaxy Redshift survey light cones constructed from the Millennium Simulation semi-analytic galaxy catalogs. From this realistic test, which incorporates the effects of galaxy bias evolution and cosmic variance, we find that the true redshift distribution of a photometric sample can, in fact, be determined accurately with cross-correlation techniques. We also compare the empirical error in the reconstruction of redshift distributions to previous analytic predictions, finding that additional components must be included in error budgets to match the simulation results. This extra error contribution is small for surveys that sample large areas of sky (>{approx}10{sup 0}-100{sup 0}), but dominant for {approx}1 deg{sup 2} fields. We conclude by presenting a step-by-step, optimized recipe for reconstructing redshift distributions from cross-correlation information using standard correlation measurements.« less

Spectroscopic studies on the interaction of cimetidine drug with biologically significant σ- and π-acceptors

NASA Astrophysics Data System (ADS)

Pandeeswaran, M.; Elango, K. P.

2010-05-01

Spectroscopic studies revealed that the interaction of cimetidine drug with electron acceptors iodine and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted through the initial formation of ionic intermediate to charge transfer (CT) complex. The CT-complexes of the interactions have been characterized using UV-vis, 1H NMR, FT-IR and GC-MS techniques. The formation of triiodide ion, I 3-, is further confirmed by the observation of the characteristic bands in the far IR spectrum for non-linear I 3- ion with C s symmetry at 156 and 131 cm -1 assigned to νas(I-I) and νs(I-I) of the I-I bond and at 73 cm -1 due to bending δ(I 3-). The rate of formation of the CT-complexes has been measured and discussed as a function of relative permittivity of solvent and temperature. The influence of relative permittivity of the medium on the rate indicated that the intermediate is more polar than the reactants and this observation was further supported by spectral studies. Based on the spectroscopic results plausible mechanisms for the interaction of the drug with the chosen acceptors were proposed and discussed and the point of attachment of the multifunctional cimetidine drug with these acceptors during the formation of CT-complex has been established.

Diagnostic Chemical Analysis of Exhaled Human Breath Using a Novel Sub-Millimeter Spectroscopic Approach

NASA Astrophysics Data System (ADS)

Fosnight, Alyssa M.; Moran, Benjamin L.; Branco, Daniela R.; Thomas, Jessica R.; Medvedev, Ivan R.

2013-06-01

As many as 3000 chemicals are reported to be found in exhaled human breath. Many of these chemicals are linked to certain health conditions and environmental exposures. Present state of the art techniques used for analysis of exhaled human breath include mass spectrometry based methods, infrared spectroscopic sensors, electro chemical sensors and semiconductor oxide based testers. Some of these techniques are commercially available but are somewhat limited in their specificity and exhibit fairly high probability of false alarm. Here, we present the results of our most recent study which demonstrated a novel application of a terahertz high resolutions spectroscopic technique to the analysis of exhaled human breath, focused on detection of ethanol in the exhaled breath of a person which consumed an alcoholic drink. This technique possesses nearly ``absolute'' specificity and we demonstrated its ability to uniquely identify ethanol, methanol, and acetone in human breath. This project is now complete and we are looking to extend this method of chemical analysis of exhaled human breath to a broader range of chemicals in an attempt to demonstrate its potential for biomedical diagnostic purposes.

On the Role of Boron in CdTe and CdZnTe Crystals

NASA Astrophysics Data System (ADS)

Pavesi, M.; Marchini, L.; Zha, M.; Zappettini, A.; Zanichelli, M.; Manfredi, M.

2011-10-01

It is well known that group III elements act as donors if they play a substitutional role at the metallic site in II-tellurides; nevertheless, several studies report both on the creation of complexes with vacancies, named A-centers, and on the involvement in self-compensation mechanisms, especially for indium. The boron concentration in II-tellurides is negligible, and its contribution to transport mechanisms has not been studied yet. For the last few years the authors have been developing a new technique to grow CdZnTe by the vertical Bridgman technique, taking advantage of encapsulation by means of boron oxide. In this way, crystals characterized by large single grains, low etch pit density, and high resistivity have been obtained. Recently, x-ray detectors with state-of-the-art performance have been produced from such crystals. Boron contamination, as a consequence of this growth method, is quite low but at least one order of magnitude above values obtained with other growth techniques. Besides being a low-cost technique which is also suitable for large-scale mass production, the encapsulated vertical Bridgman technique is quite useful to prevent dislocations, grain boundaries, and stacking faults; for these reasons, careful characterization was performed to understand the effect of boron both on the electrical properties and on the spectroscopic performance of the final crystals. Our characterization is mainly based on low-temperature photoluminescence in addition to electrical current-voltage measurements, photostimulated current, and x-ray spectroscopy. The results indicate that boron behaves like other group III elements; in fact, boron forms a complex that does not affect the good performance of our x-ray detectors, even if it shows some properties which are typical of A-centers.

Penetration kinetics of dimethyl sulphoxide and glycerol in dynamic optical clearing of porcine skin tissue in vitro studied by Fourier transform infrared spectroscopic imaging.

PubMed

Jiang, Jingying; Boese, Matthias; Turner, Paul; Wang, Ruikang K

2008-01-01

By use of a Fourier transform infrared (FTIR) spectroscopic imaging technique, we examine the dynamic optical clearing processes occurring in hyperosmotically biocompatible agents penetrating into skin tissue in vitro. The sequential collection of images in a time series provides an opportunity to assess penetration kinetics of dimethyl sulphoxide (DMSO) and glycerol beneath the surface of skin tissue over time. From 2-D IR spectroscopic images and 3-D false color diagrams, we show that glycerol takes at least 30 min to finally penetrate the layer of epidermis, while DMSO can be detected in epidermis after only 4 min of being topically applied over stratum corneum sides of porcine skin. The results demonstrate the potential of a FTIR spectroscopic imaging technique as an analytical tool for the study of dynamic optical clearing effects when the bio-tissue is impregnated by hyperosmotically biocompatible agents such as glycerol and DMSO.

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

Genest-Beaulieu, C.; Bergeron, P., E-mail: genest@astro.umontreal.ca, E-mail: bergeron@astro.umontreal.ca

We present a comparative analysis of atmospheric parameters obtained with the so-called photometric and spectroscopic techniques. Photometric and spectroscopic data for 1360 DA white dwarfs from the Sloan Digital Sky Survey (SDSS) are used, as well as spectroscopic data from the Villanova White Dwarf Catalog. We first test the calibration of the ugriz photometric system by using model atmosphere fits to observed data. Our photometric analysis indicates that the ugriz photometry appears well calibrated when the SDSS to AB{sub 95} zeropoint corrections are applied. The spectroscopic analysis of the same data set reveals that the so-called high-log g problem canmore » be solved by applying published correction functions that take into account three-dimensional hydrodynamical effects. However, a comparison between the SDSS and the White Dwarf Catalog spectra also suggests that the SDSS spectra still suffer from a small calibration problem. We then compare the atmospheric parameters obtained from both fitting techniques and show that the photometric temperatures are systematically lower than those obtained from spectroscopic data. This systematic offset may be linked to the hydrogen line profiles used in the model atmospheres. We finally present the results of an analysis aimed at measuring surface gravities using photometric data only.« less

Hydrogen bonding interactions in nicotinamide Ionic Liquids: A comparative spectroscopic and DFT studies

NASA Astrophysics Data System (ADS)

Shukla, Madhulata

2017-03-01

Being biodegradable in nature nicotinamide based Ionic Liquids (ILs) are gaining much attention now a day. Nicotinamide iodide (i.e 1-methyl-3ethoxy carbonyl pyridinium iodide (mNicI)) and 1-methyl-3ethoxy carbonyl pyridinium trifilimide (mNicNTf2) new ILs has been synthesized and has been characterized using different spectroscopic techniques like NMR, UV visible and infrared spectroscopy. Theoretical studies have been performed on several nicotinamide ILs. Geometry and spectral features were further characterized by Density Functional Theory (DFT) calculation. NBO charge distribution and electrostatic potential diagram presents in depth knowledge about interactions between cation and anion. A comparative theoretical study between mNicI and its other analogues i. e 1-methyl-3 ethoxy carbonyl pyridinium chloride and bromide i. e mNicCl and mNicBr has also been performed. Csbnd H⋯X hydrogen bonding along with C⋯X interaction has been reported for the first time for the nicotinamide based ILs. C2sbnd H stretching frequency shifts to higher wavenumber with change to a lesser electronegative anion. mNicCl and mNicBr are expected to be solid in nature with the evidence from the red shift in stretching frequency as compared to mNicI. TD-DFT calculation of mNicI proved that pale yellow color of liquid is due to inherent transition from anion to cation.

Synthesis, X-ray diffraction method, spectroscopic characterization (FT-IR, 1H and 13C NMR), antimicrobial activity, Hirshfeld surface analysis and DFT computations of novel sulfonamide derivatives

NASA Astrophysics Data System (ADS)

Demircioğlu, Zeynep; Özdemir, Fethi Ahmet; Dayan, Osman; Şerbetçi, Zafer; Özdemir, Namık

2018-06-01

Synthesized compounds of N-(2-aminophenyl)benzenesulfonamide 1 and (Z)-N-(2-((2-nitrobenzylidene)amino)phenyl)benzenesulfonamide 2 were characterized by antimicrobial activity, FT-IR, 1H and 13C NMR. Two new Schiff base ligands containing aromatic sulfonamide fragment of (Z)-N-(2-((3-nitrobenzylidene)amino)phenyl)benzenesulfonamide 3 and (Z)-N-(2-((4-nitrobenzylidene)amino)phenyl)benzenesulfonamide 4 were synthesized and investigated by spectroscopic techniques including 1H and 13C NMR, FT-IR, single crystal X-ray diffraction, Hirshfeld surface, theoretical method analyses and by antimicrobial activity. The molecular geometry obtained from the X-ray structure determination was optimized Density Functional Theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set in ground state. From the optimized geometry of the molecules of 3 and 4, the geometric parameters, vibrational wavenumbers and chemical shifts were computed. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP 6-311G++(d,p) was a successful choice. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), molecular electrostatic mep (MEP), Mulliken population method, natural population analysis (NPA) and natural bond orbital analysis (NBO), which cannot be obtained experimentally, were calculated and investigated.

Selenium nanoparticles synthesized in aqueous extract of Allium sativum perturbs the structural integrity of Calf thymus DNA through intercalation and groove binding.

PubMed

Ezhuthupurakkal, Preedia Babu; Polaki, Lokeswara Rao; Suyavaran, Arumugam; Subastri, Ariraman; Sujatha, Venugopal; Thirunavukkarasu, Chinnasamy

2017-05-01

Biomedical application of selenium nanoparticles (SeNPs) demands the eco-friendly composite for synthesis of SeNPs. The present study reports an aqueous extract of Allium sativum (AqEAS) plug-up the current need. Modern spectroscopic, microscopic and gravimetric techniques were employed to characterize the synthesized nanoparticles. Characterization studies revealed the formation of crystalline spherical shaped SeNPs. FTIR spectrum brings out the presence of different functional groups in AqEAS, which influence the SeNPs formation and stabilization. Furthermore the different aspects of the interaction between SeNPs and CT-DNA were scrutinized by various spectroscopic and cyclic voltametric studies. The results reveals the intercalation and groove binding mode of interaction of SeNPs with stacked base pair of CT-DNA. The Stern-Volmer quenching constant (K SV ) were found to be 7.02×10 6 M- 1 (ethidium bromide), 4.22×10 6 M- 1 (acridine orange) and 7.6×10 6 M- 1 (Hoechst) indicating strong binding of SeNPs with CT-DNA. The SeNPs - CT-DNA interactions were directly visualized by atomic force microscopy. The present study unveils the cost effective, innocuous, highly stable SeNPs intricate mechanism of DNA interaction, which will be a milestone in DNA targeted chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Adsorption and spectroscopic characterization of lactoferrin on hydroxyapatite nanocrystals.

PubMed

Iafisco, Michele; Di Foggia, Michele; Bonora, Sergio; Prat, Maria; Roveri, Norberto

2011-01-28

Lactoferrin (LF), a well-characterized protein of blood plasma and milk with antioxidant, cariostatic, anticarcinogenic and anti-inflammatory properties, has been adsorbed onto biomimetic hydroxyapatite (HA) nanocrystals at two different pH values (7.4 and 9.0). The interaction was herein investigated by spectroscopic, thermal and microscopic techniques. The positive electrostatic surface potential of LF at pH 7.4 allows a strong surface interaction with the slightly negative HA nanocrystals and avoids the protein-protein interaction, leading to the formation of a coating protein monolayer. In contrast, at pH 9.0 the surface potential of LF is a mix of negative and positive zones favouring the protein-protein interaction and reducing the interaction with HA nanocrystals; as a result a double layer of coating protein was formed. These experimental findings are supported by the good fittings of the adsorption isotherms by different theoretical models according to Langmuir, Freundlich and Langmuir-Freundlich models. The nanosized HA does not appreciably affect the conformation of the adsorbed protein. In fact, using FT-Raman and FT-IR, we found that after adsorption the protein was only slightly unfolded with a small fraction of the α-helix structure being converted into turn, while the β-sheet content remained almost unchanged. The bioactive surface of HA functionalized with LF could be utilized to improve the material performance towards the biological environment for biomedical applications.

Synthesis, thermal analyses, characterization and biological evaluation of new enrofloxacin vanadium(V) solvates(L) (L = An, DMF, Py, Et3N and o-Tol)

NASA Astrophysics Data System (ADS)

Zordok, Wael A.; Sadeek, Sadeek A.

2016-09-01

Five metal complexes of antibacterial agent enrofloxacin with vanadium(V) in the presence of aniline, pyridine, orthotolidine and triethylamine as nitrogen donor molecules and dimethylformamide as oxygen donor molecule have been prepared and characterized with physicochemical and diverse spectroscopic techniques (IR, UV-Vis. and 1H NMR spectroscopes) as well as thermal analysis. The deprotonated enrofloxacin complexes of V(V) were isolated as solids with the general formulas; [VO(Enr)2DMF]Cl·5H2O, [VO(Enr)2An]Cl·2H2O, [VO(Enr)2o-Tol]Cl·H2O, [VO(Enr)2Py]Cl·4H2O and [VO(Enr)2Et3N]Cl·6H2O. The prepared complexes are formed with a metal to ligand ratios as 1:2:1 for all complexes. The lowest energy model structure of each complex has been proposed by using the density functional theory (DFT) at the B3LYP/CEP-31G level of theory. The energy barrier for the pyridine complex greater than others complexes while, Et3N complex has lower value. The ligand and their metal complexes were also evaluated for their antibacterial activity against three Gram (+ve) and three Gram (-ve) microorganisms.

Optical properties of ultrathin CIGS films studied by spectroscopic ellipsometry assisted by chemical engineering

NASA Astrophysics Data System (ADS)

Loubat, Anaïs; Eypert, Céline; Mollica, Fabien; Bouttemy, Muriel; Naghavi, Negar; Lincot, Daniel; Etcheberry, Arnaud

2017-11-01

CIGS (Cu(In1-x,Gax)Se2) based devices are very efficient for photovoltaic conversion. A non-destructive optical study of CIGS is an important challenge as for evaluation of the material quality, and for device modeling. Spectroscopic Ellipsometry (SE) is well adapted for a quantitative characterization only if the handicaps of the roughness limitation, the oxidized surface, or the compositional gradient are minimized. For this SE study, ungraded and thin CIGS samples are prepared with GGI (x) ratio (=[Ga]/([Ga] + [In])) ranging from 0.15 to 0.60. Thanks to chemical engineering based on acidic bromine solution etching and/or HCl de-oxidation, the SE experiments are performed on flattened surfaces, and also, on as grown de-oxidized samples. Using assumptions based on XPS, AFM and SEM complementary characterizations, we give proof of oxide free flattening surfaces and chemical homogeneity in depth. Using these observations, the SE data are modeled on the basis of a three layer model using an Adachi/Tauc-Lorentz formula for the CIGS dispersion. The optical gap values are determined in good agreement with the x ratio measured by the other characterization techniques. SE is able to well estimate the thickness and roughness variations on each sample. Furthermore, the CIGS optical constant extracted on such reference flat surfaces are then applied to the as grown-de-oxidized surfaces, enabling to describe the SE data obtained on rougher surfaces. A complete consistency of the proposed model is shown as well as the capability of SE to be sensitive to the chemistry of the surface.

Spectroscopic characterization approach to study surfactants effect on ZnO 2 nanoparticles synthesis by laser ablation process

NASA Astrophysics Data System (ADS)

Drmosh, Q. A.; Gondal, M. A.; Yamani, Z. H.; Saleh, T. A.

2010-05-01

Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H 2O 2. The effect of surfactants on the optical and structure of ZnO 2 was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H 2O 2, and H 2O 2 mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO 2 nanoparticles prepared with and without surfactants show a characteristic ZnO 2 absorption at 435-445 cm -1. FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm -1.

Novel cholinesterase modulators and their ability to interact with DNA

NASA Astrophysics Data System (ADS)

Janockova, Jana; Gulasova, Zuzana; Musilek, Kamil; Kuca, Kamil; Kozurkova, Maria

2013-11-01

In the present work, an interaction of four cholinesterase modulators (1-4) with calf thymus DNA was studied via spectroscopic techniques (UV-Vis, fluorescent spectroscopy and circular dichroism). From UV-Vis spectroscopic analysis, the binding constants for DNA-pyridinium oximes complexes were calculated (K = 3.5 × 104 to 1.4 × 105 M-1). All these measurements indicated that the compounds behave as effective DNA-interacting agents. Electrophoretic techniques proved that ligand 2 inhibited topoisomerase I at a concentration 5 μM.

Extinction measurement of dense media by an optical coherence tomography technique

NASA Astrophysics Data System (ADS)

Ago, Tomoki; Iwai, Toshiaki; Yokota, Ryoko

2016-10-01

The optical coherence tomography will make progress as the next stage toward a spectroscopic analysis technique. The spectroscopic analysis is based on the Beer-Lambert law. The absorption and scattering coefficients even for the dense medium can be measured by the Beer-Lambert law because the OCT can detect only the light keeping the coherency which propagated rectilinearly and retro-reflected from scatters. This study is concerned with the quantitative verification of Beer-Lambert law in the OCT imaging.

High-Precision Studies of Compact Variable Stars

NASA Astrophysics Data System (ADS)

Bloemen, Steven

2014-10-01

This book, which is a reworked and updated version of Steven Bloemen's original PhD thesis, reports on several high-precision studies of compact variable stars. Its strength lies in the large variety of observational, theoretical and instrumentation techniques that are presented and used and paves the way towards new and detailed asteroseismic applications of single and binary subdwarf stars. Close binary stars are studied using high cadence spectroscopic datasets collected with state of the art electron multiplying CCDs and analysed using Doppler tomography visualization techniques. The work touches upon instrumentation, presenting the calibration of a new fast, multi-colour camera installed at the Mercator Telescope on La Palma. The thesis also includes theoretical work on the computation of the temperature range in which stellar oscillations can be driven in subdwarf B-stars. Finally, the highlight of the thesis is the measurement of velocities of stars using only photometric data from NASA's Kepler satellite. Doppler beaming causes stars to appear slightly brighter when they move towards us in their orbits, and this subtle effect can be seen in Kepler's brightness measurements. The thesis presents the first validation of such velocity measurements using independent spectroscopic measurements. Since the detection and validation of this Doppler beaming effect, it has been used in tens of studies to detect and characterize binary star systems, which are key calibrators in stellar astronomy.

Spectroscopic, electrochemical DNA binding and in vivo anti-inflammatory studies on newly synthesized Schiff bases of 4-aminophenazone.

PubMed

Arshad, Nasima; Ahmad, Mukhtar; Ashraf, Muhammad Zaman; Nadeem, Humaira

2014-09-05

4-Aminophenazone (Ap-1) Schiff bases i.e., 4-{(3,4,5-trimethoxybenzylidine) amino}phenazone (Ap-2), 4-{(2-chlorobenzylidine) amino}phenazone (Ap-3) and 4-{(4-chlorobenzylidine)amino} phenazone (Ap-4) were synthesized and characterized by different spectroscopic techniques. Interaction of these compounds with ds.DNA was investigated through UV-Visible spectroscopy, fluorescence spectroscopy and cyclic voltammetry at stomach (4.7) and blood (7.4) pH under 37 °C (human body temperature). Instrumental findings were further quantified both kinetically and thermodynamically. Results obtained through these techniques inferred intercalative mode of binding of all the compounds with DNA. The binding constant data, "Kb", and free energy change, ΔG, indicated comparatively greater binding affinity and more spontaneity of binding of compounds with DNA at stomach pH (4.7), respectively. However, among these compounds, Ap-4 showed comparatively greater binding at both the pH. Formation of compound-DNA complex was further confirmed through the decrease in diffusion rates after the addition of DNA. The in vivo anti-inflammatory activity of the compounds was evaluated using the carrageenan-induced hind paw edema method. The results revealed that among all the compounds, Ap-4 showed greater percentage of edema inhibition compared to standard drug. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of an intraluminal differential frequency-domain photoacoustics system

NASA Astrophysics Data System (ADS)

Lashkari, Bahman; Son, Jungik; Liang, Simon; Castelino, Robin; Foster, F. Stuart; Courtney, Brian; Mandelis, Andreas

2016-03-01

Cardiovascular related diseases are ranked as the second highest cause of death in Canada. Among the most important cardiovascular diseases is atherosclerosis. Current methods of diagnosis of atherosclerosis consist of angiography, intravascular ultrasound (IVUS) and optical coherence tomography (OCT). None of these methods possesses adequate sensitivity, as the ideal technique should be capable of both depth profiling, as well as functional imaging. An alternative technique is photoacoustics (PA) which can perform deep imaging and spectroscopy. The presented study explores the application of wavelength-modulated differential photoacoustic radar (WM-DPAR) for characterizing arterial vessels. The wavelength-modulated differential photoacoustic technique was shown to be able to substantially increase the dynamic range and sensitivity of hemoglobin oxygenation level detection. In this work the differential PA technique was used with a very high frequency modulation range. To perform spectroscopic PA imaging, at least two wavelengths are required. The selected wavelengths for this work are 1210 nm and 980 nm. 1210 nm corresponds to the maximum optical absorption coefficient of cholesterol and cholesteryl esters which are the main constituents of plaques. Since water, elastin and collagen also have high absorption coefficients at 1210 nm, this wavelength alone cannot provide very high sensitivity and specificity. The additional wavelength, 980 nm corresponds to high absorption coefficient of those constituents of healthy artery tissue. The simultaneous application of the abovementioned wavelengths can provide higher sensitivity and improved specificity in detecting lipids in the arterial vessels.

A non-destructive spectroscopic study of the decoration of archaeological pottery: from matt-painted bichrome ceramic sherds (southern Italy, VIII-VII B.C.) to an intact Etruscan cinerary urn

NASA Astrophysics Data System (ADS)

Bruni, Silvia; Guglielmi, Vittoria; Della Foglia, Elena; Castoldi, Marina; Bagnasco Gianni, Giovanna

2018-02-01

A study is presented based on the use of entirely non-destructive spectroscopic techniques to analyze the chemical composition of the painted surface layer of archaeological pottery. This study aims to define both the raw materials and the working technology of ancient potters. Energy-dispersive X-ray analysis, micro-Raman spectroscopy, visible and near infrared (NIR) diffuse reflection spectroscopy and external reflection Fourier-transform infrared (FTIR) spectroscopy were applied to matt-painted bichrome pottery sherds (VIII-VII century B.C.) from the site of Incoronata near Metaponto in southern Italy. Two different raw materials, ochre and iron-rich clay, were recognized for the red decoration, while the dark areas resulted to have been obtained by the so-called manganese black technique. In any case, it was demonstrated that the decoration was applied before firing, in spite of its sometimes grainy aspect that could suggest a post-firing application. For the samples with a more sophisticated decorative pattern a red/black/white polychromy was recognized, as the lighter areas correspond to an ;intentional white; obtained by the firing of a calcium-rich clay. Reflection spectroscopy in the visible-NIR and mid-IR as well as micro-Raman spectroscopy were then employed to characterize the decoration of an intact ceramic urn from the Etruscan town of Chiusi, evidencing a post-firing painting based on the use of red ochre, carbon black and lime, possibly imitating the ;fresco; technique used in wall paintings.

Characterization and Differentiation of Petroleum-Derived Products by E-Nose Fingerprints

PubMed Central

Ferreiro-González, Marta; Palma, Miguel; Ayuso, Jesús; Álvarez, José A.; Barroso, Carmelo G.

2017-01-01

Characterization of petroleum-derived products is an area of continuing importance in environmental science, mainly related to fuel spills. In this study, a non-separative analytical method based on E-Nose (Electronic Nose) is presented as a rapid alternative for the characterization of several different petroleum-derived products including gasoline, diesel, aromatic solvents, and ethanol samples, which were poured onto different surfaces (wood, cork, and cotton). The working conditions about the headspace generation were 145 °C and 10 min. Mass spectroscopic data (45–200 m/z) combined with chemometric tools such as hierarchical cluster analysis (HCA), later principal component analysis (PCA), and finally linear discriminant analysis (LDA) allowed for a full discrimination of the samples. A characteristic fingerprint for each product can be used for discrimination or identification. The E-Nose can be considered as a green technique, and it is rapid and easy to use in routine analysis, thus providing a good alternative to currently used methods. PMID:29113069

Spectroscopic characterization of effective components anthraquinones in Chinese medicinal herbs binding with serum albumins

NASA Astrophysics Data System (ADS)

Bi, Shuyun; Song, Daqian; Kan, Yuhe; Xu, Dong; Tian, Yuan; Zhou, Xin; Zhang, Hanqi

2005-11-01

The interactions of serum albumins such as human serum albumin (HSA) and bovine serum albumin (BSA) with emodin, rhein, aloe-emodin and aloin were assessed employing fluorescence quenching and absorption spectroscopic techniques. The results obtained revealed that there are relatively strong binding affinity for the four anthraquinones with HSA and BSA and the binding constants for the interactions of anthraquinones with HSA or BSA at 20 °C were obtained. Anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions. And the competition binding of anthraquinones with serum albumins was also discussed. The Stern-Volmer curves suggested that the quenching occurring in the reactions was the static quenching process. The binding distances and transfer efficiencies for each binding reactions were calculated according to the Föster theory of non-radiation energy transfer. Using thermodynamic equations, the main action forces of these reactions were also obtained. The reasons of the different binding affinities for different anthraquinone-albumin reactions were probed from the point of view of molecular structures.

Synthesis and synergistic antifungal activities of a pyrazoline based ligand and its copper(II) and nickel(II) complexes with conventional antifungals.

PubMed

Ali, Imran; Wani, Waseem A; Khan, Amber; Haque, Ashanul; Ahmad, Aijaz; Saleem, Kishwar; Manzoor, Nikhat

2012-08-01

A pyrazoline based ligand; (5-(4-chlorophenyl)-3-phenyl-4, 5-dihydro-1H-pyrazole-1-carbothioamide) has been synthesized by Claisen-Schmidt condensation of acetophenone with p-chlorobenzaldehyde, followed by sodium hydroxide assisted cyclization of the resulting chalcone with thiosemicarbazide. Metal ion complexes of the synthesized ligand were prepared with Cu(II) and Ni(II) metal ions, separately and respectively. Ligand and the metal complexes were characterized by elemental analysis, FT-IR, UV-Vis, (1)HNMR, ESI-MS and (13)CNMR spectroscopic techniques. Molar conductance measurements in DMSO suggested non-electrolytic nature of the complexes. Tetragonally distorted octahedral geometry for copper and octahedral geometry for the nickel complexes was proposed on the basis of UV-Vis spectroscopic studies and magnetic moment measurements. The complexes were investigated for their ability to kill human fungal pathogen Candida by determining MICs (Minimum inhibitory concentrations), inhibition in solid media and ability to produce a possible synergism with conventional most clinically practiced antifungals by disc diffusion assay and FICI (fractional inhibitory concentration index). Copyright © 2012 Elsevier Ltd. All rights reserved.

Photochemical tuning of ultrathin TiO2/ p-Si p-n junction properties via UV-induced H doping

NASA Astrophysics Data System (ADS)

Lee, Sang Yeon; Kim, Jinseo; Ahn, Byungmin; Cho, In Sun; Yu, Hak Ki; Seo, Hyungtak

2017-03-01

We report a modified TiO2/ p-Si electronic structure that uses ultraviolet exposure for the incorporation of H. This structure was characterized using various photoelectron spectroscopic techniques. The ultraviolet (UV) exposure of the TiO2 surface allowed the Fermi energy level to be tuned by the insertion of H radicals, which induced changes in the heterojunction TiO2/ p-Si diode properties. The UV exposure of the TiO2 surface was performed in air. On UVexposure, a photochemical reaction involving the incorporation of UV-induced H radicals led to the creation of a surface Ti-O-OH group and caused interstitial H doping (Ti-H-O) in the bulk, which modified the electronic structures in different ways, depending on the location of the H. On the basis of the band alignment determined using a combined spectroscopic analysis, it is suggested that the UV-induced H incorporation into the TiO2 could be utilized for the systematic tuning of the heterojunction property for solar cells, photocatalytic applications, and capacitors.

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

Chunshan Song; Hatcher, P.G.; Saini, A.K.

It has been indicated by DOE COLIRN panel that low-temperature catalytic pretreatment is a promising approach to the development of an improved liquefaction process. This work is a fundamental study on effects of pretreatments on coal structure and reactivity in liquefaction. The main objectives of this project are to study the coal structural changes induced by low-temperature catalytic and thermal pretreatments by using spectroscopic techniques; and to clarify the pretreatment-induced changes in reactivity or convertibility of coals. As the second volume of the final report, here we summarize our work on spectroscopic characterization of four raw coals including two subbituminousmore » coals and two bituminous coals, tetrahydrofuran (THF)-extracted but unreacted coals, the coals (THF-insoluble parts) that have been thermally pretreated. in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent, and the coals (THF-insoluble parts) that have been catalytically pretreated in the presence of a dispersed Mo sulfide catalyst in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent.« less

Effect of acid dopants in biodegradable gel polymer electrolyte and the performance in an electrochemical double layer capacitor

NASA Astrophysics Data System (ADS)

Sudhakar, Y. N.; Selvakumar, M.; Krishna Bhat, D.

2015-09-01

Proton-conducting biodegradable gellan gum gel polymer electrolytes (GPEs) have been prepared using three different dopants, namely ortho-phosphoric (o-H3PO4), sulfuric (H2SO4) and hydrochloric acids (HCl). The GPEs were cross-linked using borax. The polymeric gels were characterized by spectroscopic, thermal, ionic conductivities and dielectric measurements. Proton conductivity was in the range of 5.1 × 10-3 to 3.7 × 10-4 s cm-1 and activation energies were between 0.14 meV and 0.19 meV, at different temperatures. Among the doped acids, the H3PO4 doped GPE exhibited thermal stability at varying temperature. Electrochemical double layer capacitors (EDLCs) were fabricated using activated carbon as electrode material and GPEs. The EDLCs were tested using cyclic voltammetry, ac impedance spectroscopic and galvanostatic charge-discharge techniques. The maximum specific capacitance value was 146 F g-1 at a scan rate of 2 mV s-1. Quite stable values were obtained at a constant current density up to 1000 cycles.

[Spectral Analysis about the Pharmaceutical Cocrystal Formation of Piracetam and 3-Hydroxybenzoic Acid].

PubMed

Zhang, Hui-li; Xia, Yi; Hong, Zhi; Du, Yong

2015-07-01

Pharmaceutical cocrystal can improve physical and chemical properties of active pharmaceutical ingredient (API), meanwhile this feature has shown great potential in improving the pharmaceutical's properties and characteristics. In this study, cocrystal formation between piracetam and 3-hydroxybenzoic acid (3HBA) using grinding method has been characterized by Fourier transform infrared (FTIR), Raman and terahertz (THz) spectroscopical techniques. The vibrational modes of different motions are obtained by the assignment of the peaks in the spectra of the starting materials and the cocrystal components. FTIR, Raman and THz spectroscopical results show that the vibrational modes of the cocrystal are different from those of the starting materials. In addition, the dynamic process of the above cocrystal formation is investigated in-depth with Raman and THz spec- tra. Piracetam-3HBA cocrystal is formed pretty fast in first several minutes, and then the formation rate becomes slow. After 35 minutes, such formation process has been completed. The results offer the theoretical benchmark and unique means for real-time monitoring pharmaceutical cocrystal formation and also the corresponding quantitative analysis in the pharmaceutical field.

Molecular structure and spectroscopic characterization of Carbamazepine with experimental techniques and DFT quantum chemical calculations

NASA Astrophysics Data System (ADS)

Suhasini, M.; Sailatha, E.; Gunasekaran, S.; Ramkumaar, G. R.

2015-04-01

A systematic vibrational spectroscopic assignment and analysis of Carbamazepine has been carried out by using FT-IR, FT-Raman and UV spectral data. The vibrational analysis were aided by electronic structure calculations - ab initio (RHF) and hybrid density functional methods (B3LYP) performed with standard basis set 6-31G(d,p). Molecular equilibrium geometries, electronic energies, natural bond order analysis, harmonic vibrational frequencies and IR intensities have been computed. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED) by VEDA program. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λmax were determined by HF/6-311++G(d,p) Time-Dependent method. The thermodynamic functions of the title molecule were also performed using the RHF and DFT methods. The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance (NMR) calculation procedure was also performed, and it was used for assigning the 13C and 1H NMR chemical shifts of Carbamazepine.

Ion beam radiation effects on natural halite crystals

NASA Astrophysics Data System (ADS)

Arun, T.; Ram, S. S.; Karthikeyan, B.; Ranjith, P.; Ray, D. K.; Rout, B.; Krishna, J. B. M.; Sengupta, Pranesh; Parlapalli, Venkata Satyam

2017-10-01

Halites are one of the interesting material due to its color variations. Natural halites whose color ranges from transparent to dark blue were studied by UV-VIS and Raman spectroscopy. The halite crystals were irradiated with 3 MeV proton micro-beam (∼20 μm beam width with ∼80 PA beam current) for 10 and 90 min to study the radiation damage. After 10 mins of irradiation, small spot developed on the surface of transparent halite crystal whereas after 90 mins of irradiation the spot spread inside the bulk leading to a brown coloration (20 μm initial size to ∼2.0 mm final size). The irradiated portion and the un-irradiated portion of the halites was characterized by Raman spectroscopic technique. The variation in the population density was observed from the UV-Vis spectra. The change in the Raman band intensities was observed for transparent, blue colored and proton beam irradiation halites. Such variation of spectroscopic characteristics due to proton irradiation suggests that the halite can be used for the radiation monitoring.

4-Cyano-α-methyl-l-phenylalanine as a spectroscopic marker for the investigation of peptaibiotic-membrane interactions.

PubMed

De Zotti, Marta; Bobone, Sara; Bortolotti, Annalisa; Longo, Edoardo; Biondi, Barbara; Peggion, Cristina; Formaggio, Fernando; Toniolo, Claudio; Dalla Bona, Andrea; Kaptein, Bernard; Stella, Lorenzo

2015-04-01

Two analogs of the ten-amino acid residue, membrane-active lipopeptaibiotic trichogin GA IV, mono-labeled with 4-cyano-α-methyl-L-phenylalanine, a potentially useful fluorescence and IR absorption probe of the local microenvironment, were synthesized by the solid-phase methodology and conformationally characterized. The single modification was incorporated either at the N-terminus (position 1) or near the C-terminus (position 8) of the peptide main chain. In both cases, the replaced amino acid was the equally helicogenic α-aminoisobutyric acid (Aib) residue. We performed a solution conformational analysis by use of FT-IR absorption, CD, and 2D-NMR spectroscopies. The results indicate that both labeled analogs essentially maintain the overall helical propensity of the naturally occurring lipopeptaibiotic. Peptide-membrane interactions were assessed by fluorescence and ATR-IR absorption techniques. Analogies and differences between the two peptides were highlighted. Taken together, our data confirm literature results that some of the spectroscopic parameters of the 4-cyanobenzyl chromophore are sensitive markers of the local microenvironment. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Spectroscopic studies on sidewall carboxylic acid functionalization of multi-walled carbon nanotubes with valine.

PubMed

Deborah, M; Jawahar, A; Mathavan, T; Dhas, M Kumara; Benial, A Milton Franklin

2015-03-15

The valine functionalized multi-walled carbon nanotubes (MWCNTS) were prepared and characterized by using XRD, UV-Vis, FT-IR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (002) intensity was observed for valine functionalized MWCNTs compared with oxidized MWCNTs, which is likely due to sample purification by acid washing. UV-Vis study shows the formation of valine functionalized MWCNTs. FT-IR study confirms the presence of functional groups of oxidized MWCNTs and valine functionalized MWCNTs. The ESR line shape analysis indicates that the observed EPR line shape is a Gaussian line shape. The g-values indicate that the systems are isotropic in nature. The morphology study was carried out for oxidized MWCNTs and valine functionalized MWCNTs by using SEM. The EDX spectra revealed that the high purity of oxidized MWCNTs and valine functionalized MWCNTs. The functionalization has been chosen because, functionalization of CNTs with amino acids makes them soluble and biocompatible. Thus, they have potential applications in the field of biosensors and targeted drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

Methyl-cyclopentadienyl Ruthenium Compounds with 2,2'-Bipyridine Derivatives Display Strong Anticancer Activity and Multidrug Resistance Potential.

PubMed

Côrte-Real, Leonor; Teixeira, Ricardo G; Gírio, Patrícia; Comsa, Elisabeta; Moreno, Alexis; Nasr, Rachad; Baubichon-Cortay, Hélène; Avecilla, Fernando; Marques, Fernanda; Robalo, M Paula; Mendes, Paulo; Ramalho, João P Prates; Garcia, M Helena; Falson, Pierre; Valente, Andreia

2018-04-16

New ruthenium methyl-cyclopentadienyl compounds bearing bipyridine derivatives with the general formula [Ru(η 5 -MeCp)(PPh 3 )(4,4'-R-2,2'-bpy)] + (Ru1, R = H; Ru2, R = CH 3 ; and Ru3, R = CH 2 OH) have been synthesized and characterized by spectroscopic and analytical techniques. Ru1 crystallized in the monoclinic P2 1 / c, Ru2 in the triclinic P1̅, and Ru3 in the monoclinic P2 1 / n space group. In all molecular structures, the ruthenium center adopts a "piano stool" distribution. Density functional theory calculations were performed for all complexes, and the results support spectroscopic data. Ru1 and Ru3 were poor substrates of the main multidrug resistance human pumps, ABCB1, ABCG2, ABCC1, and ABCC2, while Ru2 displayed inhibitory properties of ABCC1 and ABCC2 pumps. Importantly, all compounds displayed a very high cytotoxic profile for ovarian cancer cells (sensitive and resistant) that was much more pronounced than that observed with cisplatin, making them very promising anticancer agents.

Design, Synthesis, Structural and Spectroscopic Studies of Push-Pull Two-Photon Absorbing Chromophores with Acceptor Groups of Varying Strength

PubMed Central

Morales, Alma R.; Frazer, Andrew; Woodward, Adam W.; Ahn-White, Hyo-Yang; Fonari, Alexandr; Tongwa, Paul; Timofeeva, Tatiana; Belfield, Kevin D.

2013-01-01

A new series of unsymmetrical diphenylaminofluorene-based chromophores with various strong π-electron acceptors were synthesized and fully characterized. The systematic alteration of the structural design facilitated the investigation of effects such as molecular symmetry and strength of electron-donating and/or withdrawing termini have on optical nonlinearity. In order to determine the electronic and geometrical properties of the novel compounds, a thorough investigation was carried out by a combination of linear and nonlinear spectroscopic techniques, single crystal X-ray diffraction, and quantum chemical calculations. Finally, on the basis of two-photon absorption (2PA) cross sections, the general trend for π -electron accepting ability, i.e., ability to accept charge transfer from diphenylamine was: 2-pyran-4-ylidene malononitrile (pyranone) > dicyanovinyl > bis(dicyanomethylidene)indane > 1-(thiophen-2-yl)propenone > dicyanoethylenyl > 3-(thiophen-2-yl)propenone. An analog with the 2-pyran-4-ylidene malononitrile acceptor group exhibited a nearly three-fold enhancement of the 2PA< δ (1650 GM at 840 nm), relative to other members of the series. PMID:23305555

A spectroscopic study of Brazilwood paints in medieval books of hours.

PubMed

Melo, Maria João; Otero, Vanessa; Vitorino, Tatiana; Araújo, Rita; Muralha, Vânia S F; Lemos, Ana; Picollo, Marcello

2014-01-01

In this work, microspectrofluorimetry was for the first time applied to the identification of the red organic lakes that are characteristic of the lavish illuminations found in 15(th) century books of hours. Microspectrofluorimetry identified those red paints, ranging from opaque pink to dark red glazes, as brazilwood lakes. An unequivocal characterization was achieved by comparison with reference paints produced following recipes from the medieval treatise The Book on How to Make Colours, and was further confirmed by fiber optic reflectance spectroscopy (FORS). For these treasured cultural objects, microspectrofluorimetry and FORS proved to be the only techniques that could identify, in situ or in microsamples, the chromophore responsible for the pinkish hues: a brazilein-Al(3+) complex. Additionally, a multi-analytical approach provided a full characterization of the color paints, including pigments, additives, and binders. Microspectroscopic techniques, based on infrared and X-ray radiation, enabled us to disclose the full palette of these medieval manuscripts, including the elusive greens, for which, besides malachite, basic copper sulfates were found; Raman microscopy suggested a mixture of brochantite and langite. Infrared analysis proved invaluable for a full characterization of the additives that were applied as fillers or whites (chalk, gypsum, and white lead) as well as the proteinaceous and polysaccharide binders that were found pure or in mixture.

Scanning Tunneling Optical Resonance Microscopy Developed

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Raffaelle, Ryne P.; Lau, Janis E.; Jenkins, Phillip P.; Castro, Stephanie L.; Tin, Padetha; Wilt, David M.; Pal, Anna Maria; Fahey, Stephen D.

2004-01-01

The ability to determine the in situ optoelectronic properties of semiconductor materials has become especially important as the size of device architectures has decreased and the development of complex microsystems has increased. Scanning Tunneling Optical Resonance Microscopy, or STORM, can interrogate the optical bandgap as a function of its position within a semiconductor micro-structure. This technique uses a tunable solidstate titanium-sapphire laser whose output is "chopped" using a spatial light modulator and is coupled by a fiber-optic connector to a scanning tunneling microscope in order to illuminate the tip-sample junction. The photoenhanced portion of the tunneling current is spectroscopically measured using a lock-in technique. The capabilities of this technique were verified using semiconductor microstructure calibration standards that were grown by organometallic vapor-phase epitaxy. Bandgaps characterized by STORM measurements were found to be in good agreement with the bulk values determined by transmission spectroscopy and photoluminescence and with the theoretical values that were based on x-ray diffraction results.

Infrared spectroscopic imaging: Label-free biochemical analysis of stroma and tissue fibrosis.

PubMed

Nazeer, Shaiju S; Sreedhar, Hari; Varma, Vishal K; Martinez-Marin, David; Massie, Christine; Walsh, Michael J

2017-11-01

Infrared spectroscopic tissue imaging is a potentially powerful adjunct tool to current histopathology techniques. By coupling the biochemical signature obtained through infrared spectroscopy to the spatial information offered by microscopy, this technique can selectively analyze the chemical composition of different features of unlabeled, unstained tissue sections. In the past, the tissue features that have received the most interest were parenchymal and epithelial cells, chiefly due to their involvement in dysplasia and progression to carcinoma; however, the field has recently turned its focus toward stroma and areas of fibrotic change. These components of tissue present an untapped source of biochemical information that can shed light on many diverse disease processes, and potentially hold useful predictive markers for these same pathologies. Here we review the recent applications of infrared spectroscopic imaging to stromal and fibrotic regions of diseased tissue, and explore the potential of this technique to advance current capabilities for tissue analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pharmaceutical cocrystals, salts and polymorphs: Advanced characterization techniques.

PubMed

Pindelska, Edyta; Sokal, Agnieszka; Kolodziejski, Waclaw

2017-08-01

The main goal of a novel drug development is to obtain it with optimal physiochemical, pharmaceutical and biological properties. Pharmaceutical companies and scientists modify active pharmaceutical ingredients (APIs), which often are cocrystals, salts or carefully selected polymorphs, to improve the properties of a parent drug. To find the best form of a drug, various advanced characterization methods should be used. In this review, we have described such analytical methods, dedicated to solid drug forms. Thus, diffraction, spectroscopic, thermal and also pharmaceutical characterization methods are discussed. They all are necessary to study a solid API in its intrinsic complexity from bulk down to the molecular level, gain information on its structure, properties, purity and possible transformations, and make the characterization efficient, comprehensive and complete. Furthermore, these methods can be used to monitor and investigate physical processes, involved in the drug development, in situ and in real time. The main aim of this paper is to gather information on the current advancements in the analytical methods and highlight their pharmaceutical relevance. Copyright © 2017 Elsevier B.V. All rights reserved.

Spectroscopic characterization of galaxy clusters in RCS-1: spectroscopic confirmation, redshift accuracy, and dynamical mass-richness relation

NASA Astrophysics Data System (ADS)

Gilbank, David G.; Barrientos, L. Felipe; Ellingson, Erica; Blindert, Kris; Yee, H. K. C.; Anguita, T.; Gladders, M. D.; Hall, P. B.; Hertling, G.; Infante, L.; Yan, R.; Carrasco, M.; Garcia-Vergara, Cristina; Dawson, K. S.; Lidman, C.; Morokuma, T.

2018-05-01

We present follow-up spectroscopic observations of galaxy clusters from the first Red-sequence Cluster Survey (RCS-1). This work focuses on two samples, a lower redshift sample of ˜30 clusters ranging in redshift from z ˜ 0.2-0.6 observed with multiobject spectroscopy (MOS) on 4-6.5-m class telescopes and a z ˜ 1 sample of ˜10 clusters 8-m class telescope observations. We examine the detection efficiency and redshift accuracy of the now widely used red-sequence technique for selecting clusters via overdensities of red-sequence galaxies. Using both these data and extended samples including previously published RCS-1 spectroscopy and spectroscopic redshifts from SDSS, we find that the red-sequence redshift using simple two-filter cluster photometric redshifts is accurate to σz ≈ 0.035(1 + z) in RCS-1. This accuracy can potentially be improved with better survey photometric calibration. For the lower redshift sample, ˜5 per cent of clusters show some (minor) contamination from secondary systems with the same red-sequence intruding into the measurement aperture of the original cluster. At z ˜ 1, the rate rises to ˜20 per cent. Approximately ten per cent of projections are expected to be serious, where the two components contribute significant numbers of their red-sequence galaxies to another cluster. Finally, we present a preliminary study of the mass-richness calibration using velocity dispersions to probe the dynamical masses of the clusters. We find a relation broadly consistent with that seen in the local universe from the WINGS sample at z ˜ 0.05.

Concentric Rings K-Space Trajectory for Hyperpolarized 13C MR Spectroscopic Imaging

PubMed Central

Jiang, Wenwen; Lustig, Michael; Larson, Peder E.Z.

2014-01-01

Purpose To develop a robust and rapid imaging technique for hyperpolarized 13C MR Spectroscopic Imaging (MRSI) and investigate its performance. Methods A concentric rings readout trajectory with constant angular velocity is proposed for hyperpolarized 13C spectroscopic imaging and its properties are analyzed. Quantitative analyses of design tradeoffs are presented for several imaging scenarios. The first application of concentric rings on 13C phantoms and in vivo animal hyperpolarized 13C MRSI studies were performed to demonstrate the feasibility of the proposed method. Finally, a parallel imaging accelerated concentric rings study is presented. Results The concentric rings MRSI trajectory has the advantages of acquisition timesaving compared to echo-planar spectroscopic imaging (EPSI). It provides sufficient spectral bandwidth with relatively high SNR efficiency compared to EPSI and spiral techniques. Phantom and in vivo animal studies showed good image quality with half the scan time and reduced pulsatile flow artifacts compared to EPSI. Parallel imaging accelerated concentric rings showed advantages over Cartesian sampling in g-factor simulations and demonstrated aliasing-free image quality in a hyperpolarized 13C in vivo study. Conclusion The concentric rings trajectory is a robust and rapid imaging technique that fits very well with the speed, bandwidth, and resolution requirements of hyperpolarized 13C MRSI. PMID:25533653

Advanced Characterization Techniques for Sodium-Ion Battery Studies

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

Shadike, Zulipiya; Zhao, Enyue; Zhou, Yong-Ning

Sodium (Na)-ion batteries (NIBs) are considered promising alternative candidates to the well-commercialized lithium-ion batteries, especially for applications in large-scale energy storage systems. The electrochemical performance of NIBs such as the cyclability, rate capability, and voltage profiles are strongly dependent on the structural and morphological evolution, phase transformation, sodium-ion diffusion, and electrode/electrolyte interface reconstruction during charge–discharge cycling. Therefore, in-depth understanding of the structure and kinetics of electrode materials and the electrode/electrolyte interfaces is essential for optimizing current NIB systems and exploring new materials for NIBs. Recently, rapid progress and development in spectroscopic, microscopic, and scattering techniques have provided extensive insight intomore » the nature of structural evolution, morphological changes of electrode materials, and electrode/electrolyte interface in NIBs. Here in this review, a comprehensive overview of both static (ex situ) and real-time (in situ or in operando) techniques for studying the NIBs is provided. Lastly, special focus is placed on how these techniques are applied to the fundamental investigation of NIB systems and what important results are obtained.« less

Method for accurate registration of tissue autofluorescence imaging data with corresponding histology: a means for enhanced tumor margin assessment

NASA Astrophysics Data System (ADS)

Unger, Jakob; Sun, Tianchen; Chen, Yi-Ling; Phipps, Jennifer E.; Bold, Richard J.; Darrow, Morgan A.; Ma, Kwan-Liu; Marcu, Laura

2018-01-01

An important step in establishing the diagnostic potential for emerging optical imaging techniques is accurate registration between imaging data and the corresponding tissue histopathology typically used as gold standard in clinical diagnostics. We present a method to precisely register data acquired with a point-scanning spectroscopic imaging technique from fresh surgical tissue specimen blocks with corresponding histological sections. Using a visible aiming beam to augment point-scanning multispectral time-resolved fluorescence spectroscopy on video images, we evaluate two different markers for the registration with histology: fiducial markers using a 405-nm CW laser and the tissue block's outer shape characteristics. We compare the registration performance with benchmark methods using either the fiducial markers or the outer shape characteristics alone to a hybrid method using both feature types. The hybrid method was found to perform best reaching an average error of 0.78±0.67 mm. This method provides a profound framework to validate diagnostical abilities of optical fiber-based techniques and furthermore enables the application of supervised machine learning techniques to automate tissue characterization.

Advanced Characterization Techniques for Sodium-Ion Battery Studies

DOE PAGES

Shadike, Zulipiya; Zhao, Enyue; Zhou, Yong-Ning; ...

2018-02-19

Sodium (Na)-ion batteries (NIBs) are considered promising alternative candidates to the well-commercialized lithium-ion batteries, especially for applications in large-scale energy storage systems. The electrochemical performance of NIBs such as the cyclability, rate capability, and voltage profiles are strongly dependent on the structural and morphological evolution, phase transformation, sodium-ion diffusion, and electrode/electrolyte interface reconstruction during charge–discharge cycling. Therefore, in-depth understanding of the structure and kinetics of electrode materials and the electrode/electrolyte interfaces is essential for optimizing current NIB systems and exploring new materials for NIBs. Recently, rapid progress and development in spectroscopic, microscopic, and scattering techniques have provided extensive insight intomore » the nature of structural evolution, morphological changes of electrode materials, and electrode/electrolyte interface in NIBs. Here in this review, a comprehensive overview of both static (ex situ) and real-time (in situ or in operando) techniques for studying the NIBs is provided. Lastly, special focus is placed on how these techniques are applied to the fundamental investigation of NIB systems and what important results are obtained.« less

Synthesis, spectroscopic characterization (FT-IR, FT-Raman, and NMR), quantum chemical studies and molecular docking of 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione

NASA Astrophysics Data System (ADS)

Avdović, Edina H.; Milenković, Dejan; Dimitrić Marković, Jasmina M.; Đorović, Jelena; Vuković, Nenad; Vukić, Milena D.; Jevtić, Verica V.; Trifunović, Srećko R.; Potočňák, Ivan; Marković, Zoran

2018-04-01

The experimental and theoretical investigations of structure of the 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione were performed. X-ray structure analysis and spectroscopic methods (FTIR and FT-Raman, 1H and 13C NMR), along with the density functional theory calculations (B3LYP functional with empirical dispersion corrections D3BJ in combination with the 6-311 + G(d,p) basis set), were used in order to characterize the molecular structure and spectroscopic behavior of the investigated coumarin derivative. Molecular docking analysis was carried out to identify the potency of inhibition of the title molecule against human's Ubiquinol-Cytochrome C Reductase Binding Protein (UQCRB) and Methylenetetrahydrofolate reductase (MTHFR). The inhibition activity was obtained for ten conformations of ligand inside the proteins.

Accurate structural and spectroscopic characterization of prebiotic molecules: The neutral and cationic acetyl cyanide and their related species.

PubMed

Bellili, A; Linguerri, R; Hochlaf, M; Puzzarini, C

2015-11-14

In an effort to provide an accurate structural and spectroscopic characterization of acetyl cyanide, its two enolic isomers and the corresponding cationic species, state-of-the-art computational methods, and approaches have been employed. The coupled-cluster theory including single and double excitations together with a perturbative treatment of triples has been used as starting point in composite schemes accounting for extrapolation to the complete basis-set limit as well as core-valence correlation effects to determine highly accurate molecular structures, fundamental vibrational frequencies, and rotational parameters. The available experimental data for acetyl cyanide allowed us to assess the reliability of our computations: structural, energetic, and spectroscopic properties have been obtained with an overall accuracy of about, or better than, 0.001 Å, 2 kcal/mol, 1-10 MHz, and 11 cm(-1) for bond distances, adiabatic ionization potentials, rotational constants, and fundamental vibrational frequencies, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for guiding future experimental investigations and/or astronomical observations.

Characterization of spatial manipulation on ZnO nanocomposites consisting of Au nanoparticles, a graphene layer, and ZnO nanorods

NASA Astrophysics Data System (ADS)

Huang, Shen-Che; Lu, Chien-Cheng; Su, Wei-Ming; Weng, Chen-Yuan; Chen, Yi-Cian; Wang, Shing-Chung; Lu, Tien-Chang; Chen, Ching-Pang; Chen, Hsiang

2018-01-01

Three types of ZnO-based nanocomposites were fabricated consisting of 80-nm Au nanoparticles (NPs), a graphene layer, and ZnO nanorods (NRs). To investigate interactions between the ZnO NRs and Au nanoparticle, multiple material analysis techniques including field-emission scanning electron microscopy (FESEM), surface contact angle measurements, secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic characterizations were performed. Results indicate that incorporating a graphene layer could block the interaction between the ZnO NRs and the Au NPs. Furthermore, the Raman signal of the Au NPs could be enhanced by inserting a graphene layer on top of the ZnO NRs. Investigation of these graphene-incorporated nanocomposites would be helpful to future studies of the physical properties and Raman analysis of the ZnO-based nanostructure design.

Mössbauer spectroscopy.

PubMed

Huynh, Boi Hanh

2011-01-01

Mössbauer spectroscopy has contributed significantly to the studies of Fe-containing proteins. Early applications yielded detailed electronic characterizations of hemeproteins, and thus enhanced our understanding of the chemical properties of this important class of proteins. The next stage of the applications was marked by major discoveries of several novel Fe clusters of complex structures, including the 8Fe7S P cluster and the mixed metal 1Mo7Fe M center in nitrogenase. Since early 1990 s, rapid kinetic techniques have been used to arrest enzymatic reactions for Mössbauer studies. A number of reaction intermediates were discovered and characterized, both spectroscopically and kinetically, providing unprecedented detailed molecular-level mechanistic information. This chapter gives a brief summary of the historical accounts and a concise description of some experimental and theoretical elements in Mössbauer spectroscopy that are essential for understanding Mössbauer spectra. Major biological applications are summarized at the end.

Micro-XRF for characterization of Moroccan glazed ceramics and Portuguese tiles

NASA Astrophysics Data System (ADS)

Guilherme, A.; Manso, M.; Pessanha, S.; Zegzouti, A.; Elaatmani, M.; Bendaoud, R.; Coroado, J.; dos Santos, J. M. F.; Carvalho, M. L.

2013-02-01

A set of enamelled terracotta samples (Zellij) collected from five different monuments in Morocco were object of study. With the aim of characterizing these typically Moroccan artistic objects, X-ray spectroscopic techniques were used as analytical tool to provide elemental and compound information. A lack of information about these types of artistic ceramics is found by the research through international scientific journals, so this investigation is an opportunity to fulfill this gap. For this purpose, micro-Energy Dispersive X-ray Fluorescence (μ-EDXRF), and wavelength dispersive X-ray Fluorescence (WDXRF) and X-ray Diffraction (XRD) were the chosen methods. As complementary information, a comparison with other sort of artistic pottery objects is given, more precisely with Portuguese glazed wall tiles (Azulejos), based in the Islamic pottery traditions. Differences between these two types of decorative pottery were found and presented in this manuscript.

Ultrasound-assisted green bromination of N-cinnamoyl amino acid amides - Structural characterization and antimicrobial evaluation

NASA Astrophysics Data System (ADS)

Stoykova, Boyka; Chochkova, Maya; Ivanova, Galya; Markova, Nadezhda; Enchev, Venelin; Tsvetkova, Iva; Najdenski, Hristo; Štícha, Martin; Milkova, Tsenka

2017-05-01

N-phenylpropenoyl amino acid amides have been brominated using two alternative sonochemically activated green chemistry procedures. The first synthetic procedure has involved an ultrasound assisted bromination in an aqueous medium using ionic liquid as a catalyst of the reaction, whereas in the second one an in situ formation of Br2 via oxidation of HBr by H2O2 has been used. For comparison, the conventional bromination procedure was also used. The newly brominated compounds were characterized by appropriate analytical techniques. A detailed NMR spectroscopic analysis and quantum chemical calculations using Density Functional Theory (DFT) methods have been used to define the stereochemistry of the products. The results confirmed the physicochemical identity and similar yields of the products obtained by the three synthetic procedures employed, and reveal the co-existence of two diastereoisomeric forms of the newly synthesized products. The antibacterial and antifungal activities of the dibrominated amides were evaluated.

Novel aldehyde and thiosemicarbazone derivatives: Synthesis, spectroscopic characterization, structural studies and molecular docking studies

NASA Astrophysics Data System (ADS)

Karakurt, Tuncay; Tahtaci, Hakan; Subasi, Nuriye Tuna; Er, Mustafa; Ağar, Erbil

2016-12-01

In this study our purpose is that, synthesis and characterization of compounds containing the aldehyde and thiosemicarbazone groups and comparison of the theoretical results with the experimental results. The structures of all synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses techniques. The structure of compound (4) (C9H8N4O2S) was also elucidated by X-ray diffraction analysis. In addition, the theoretical IR spectrum, 1H NMR and 13C NMR chemical shift values, frontier molecular orbital values (FMO) of these molecules were analyzed by using Becke-3- Lee-Yang-Parr (B3LYP) method with LanL2DZ basis set. Finally, molecular docking studies were performed on synthesized compounds using the 4DKI beta-lactam protein structure to determine the potential binding mode of inhibitors.

Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

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

Chakraborty, Anindita; Maji, Tapas Kumar, E-mail: tmaji@jncasr.ac.in

2014-12-01

Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF) precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N{sub 2} adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared tomore » only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO{sub 2} adsorption at room temperature.« less

Non-covalent interactions in 2-methylimidazolium copper(II) complex (MeImH)2[Cu(pfbz)4]: Synthesis, characterization, single crystal X-ray structure and packing analysis

NASA Astrophysics Data System (ADS)

Sharma, Raj Pal; Saini, Anju; Kumar, Santosh; Kumar, Jitendra; Sathishkumar, Ranganathan; Venugopalan, Paloth

2017-01-01

A new anionic copper(II) complex, (MeImH)2 [Cu(pfbz)4] (1) where, MeImH = 2-methylimidazolium and pfbz = pentafluorobenzoate has been isolated by reacting copper(II) sulfate pentahydrate, pentafluorobenzoic acid and 2-methylimidazole in ethanol: water mixture in 1:2:2 molar ratio. This complex 1 has been characterized by elemental analysis, thermogravimetric analysis, spectroscopic techniques (UV-Vis, FT-IR) and conductance measurements. The complex salt crystallizes in monoclinic crystal system with space group C2/c. Single crystal X-ray structure determination revealed the presence of discrete ions: [Cu(pfbz)4]2- anion and two 2-methylimidazolium cation (C4H7N2)+. The crystal lattice is stabilized by strong hydrogen bonding and F⋯F interactions between cationic-anionic and the anionic-anionic moieties respectively, besides π-π interactions.

Molecular characterization of the plant biopolyester cutin by AFM and spectroscopic techniques.

PubMed

Benítez, José J; Matas, Antonio J; Heredia, Antonio

2004-08-01

Atomic force microscopy, FT-IR spectroscopy, and solid-state nuclear magnetic resonance have been used to improve our current knowledge on the molecular characteristics of the biopolyester cutin, the main component of the plant cuticle. After comparison of samples of cutin isolated from young and mature tomato fruit cuticles has been possible to establish different degrees of cross-linking in the biopolymer and that the polymer is mainly formed after esterification of secondary hydroxyl groups of the monomers that form this type of cutin. Atomic force microscopy gave useful structural information on the molecular topography of the outer surface of the isolated samples. The texture of these samples is a consequence of the cross-linking degree or chemical status of the polymer. Thus, the more dense and cross-linked cutin from ripe or mature tomato fruit is characterized by a flatter and more globular texture in addition to the development of elongated and orientated superstructures.

Synthesis, structural characterization and tautomeric properties of some novel bis-azo dyes derived from 5-arylidene-2,4-thiazolidinone

NASA Astrophysics Data System (ADS)

Mohammadi, Asadollah; Safarnejad, Mastaneh

Nine new bis-azo dyes derived from 5-arylidene-2,4-thiazolidinone have been synthesized in two steps using Knoevenagel condensation and diazotization-coupling reaction. The structures of the compounds were confirmed by UV-vis, IR, 1H NMR and 13C NMR spectroscopic techniques. The spectral characterizations demonstrate that there is an equilibrium between the azo (T1) and hydrazine (T2 and T3) tautomers for all prepared dyes in solutions. In addition, the solvatochromic behavior of the prepared dyes was evaluated using polarity/polarizability parameter (π*) in various solvents. The UV-vis absorption spectra of dyes show a bathochromic shift with increasing polarity and base strength of the solvents. Finally, the effects of acid and base on the UV-vis absorption spectra of the dyes with different substituent in diazo component are reported.

Polyimide characterization studies - Effect of pendant alkyl groups

NASA Technical Reports Server (NTRS)

Jensen, B. J.; Young, P. R.

1984-01-01

The effect on selected polyimide properties when pendant alkyl groups were attached to the polymer backbone was investigated. A series of polymers were prepared using benzophenone tetracarboxylic acid dianhydride (BTDA) and seven different p-alkyl-m,p'-diaminobenzophenone monomers. The alkyl groups varied in length from C(1) (methyl) to C(9) (nonyl). The polyimide prepared from BTDA and m,p'-diaminobenzophenone was included as a control. All polymers were characterized by various chromatographic, spectroscopic, thermal, and mechanical techniques. Increasing the length of the pendant alkyl group resulted in a systematic decrease in glass transition temperature (Tg) for vacuum cured films. A 70 C decrease in Tg to 193 C was observed for the nonyl polymer compared to the Tg for the control. A corresponding systematic increase in Tg indicative of crosslinking, was observed for air cured films. Thermogravimetric analysis revealed a slight sacrifice in thermal stability with increasing alkyl length. No improvement in film toughness was observed.

Synthesis, characterization, and corrosion protection properties of poly( N-(methacryloyloxymethyl) benzotriazole- co-methyl methacrylate) on mild steel

NASA Astrophysics Data System (ADS)

Srikanth, A. P.; Lavanya, A.; Nanjundan, S.; Rajendran, N.

2006-12-01

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and 13C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.

Spectroscopic characterization of charge-transfer complexes of morpholine with chloranilic and picric acids in organic media: crystal structure of bis(morpholinium 2,4,6-trinitrocyclohexanolate).

PubMed

Refat, Moamen S; El-Zayat, Lamia A; Yeşilel, Okan Zafer

2010-02-01

Electron donor-acceptor interaction of morpholine (morp) with chloranilic acid (cla) and picric acid (pa) as pi-acceptors was investigated spectrophotometrically and found to form stable charge-transfer (CT) complexes (n-pi*) of [(Hmorp)(2)(cla)] and [(Hmorp)(pa)](2). The donor site involved in CT interaction is morpholine nitrogen. These complexes are easily synthesized from the reaction of morp with cla and pa within MeOH and CHCl(3) solvents, respectively. (1)HNMR, IR, elemental analyses, and UV-vis techniques characterize the two morpholinium charge-transfer complexes. Benesi-Hildebrand and its modification methods were applied to the determination of association constant (K), molar extinction coefficient (epsilon). The X-ray crystal structure was carried out for the interpretation the predict structure of the [(Hmorp)(pa)](2) complex. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Spectroscopic characterization of charge-transfer complexes of morpholine with chloranilic and picric acids in organic media: Crystal structure of bis(morpholinium 2,4,6-trinitrocyclohexanolate)

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; El-Zayat, Lamia A.; Yeşilel, Okan Zafer

2010-02-01

Electron donor-acceptor interaction of morpholine (morp) with chloranilic acid (cla) and picric acid (pa) as π-acceptors was investigated spectrophotometrically and found to form stable charge-transfer (CT) complexes (n-π*) of [(Hmorp) 2(cla)] and [(Hmorp)(pa)] 2. The donor site involved in CT interaction is morpholine nitrogen. These complexes are easily synthesized from the reaction of morp with cla and pa within MeOH and CHCl 3 solvents, respectively. 1HNMR, IR, elemental analyses, and UV-vis techniques characterize the two morpholinium charge-transfer complexes. Benesi-Hildebrand and its modification methods were applied to the determination of association constant ( K), molar extinction coefficient ( ɛ). The X-ray crystal structure was carried out for the interpretation the predict structure of the [(Hmorp)(pa)] 2 complex.

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

Ali Sinag; Melike Sungur; Mustafa Gullu

This study describes the detailed hydrocarbon type characterization of the tar (liquid phase) obtained by copyrolysis of Mustafa Kemal Paa (M.K.P.) lignite (Turkey) and low density polyethylene (LDPE) and by pyrolysis of coal and LDPE individually. Various spectroscopic techniques (gas chromatography-mass spectroscopy (GC-MS), nuclear magnetic resonance spectroscopy ({sup 1}H NMR), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC)) are used for characterization, and the effect of the experimental conditions (temperature, lignite:low density polyethylene (LDPE) ratio, and catalyst) on the hydrocarbon distributions is discussed. The results show that the tars obtained by copyrolysis have similar properties with commercial gasolinemore » (especially in the presence of Red mud). Red mud and bentonite used as catalysts make a positive effect on the production of olefins instead aromatics. Polyethylene acts as a hydrogenation medium for the coal product as revealed by FTIR results. 18 refs., 9 figs., 5 tabs.« less

On the Use of Line Depth Ratios to Measure Starspot Properties on Magnetically Active Stars

NASA Astrophysics Data System (ADS)

O'Neal, Douglas

2006-07-01

Photometric and spectroscopic techniques have proven to be effective ways to measure the properties of dark, cool starspots on magnetically active stars. Recently, a technique was introduced using atomic line depth ratios (LDRs) to measure starspot properties. Carefully reproducing this technique using a new set of spectroscopic observations of active stars, we find that the LDR technique encounters difficulties, specifically by overestimating spot temperatures (because the atomic lines blend with titanium oxide absorption in cooler spots) and by not tightly constraining the filling factor of spots. While the use of LDRs for active star studies has great promise, we believe that these concerns need to be addressed before the technique is more widely applied. This paper includes data taken at McDonald Observatory of the University of Texas at Austin.

FT-Raman and NIR spectroscopy data fusion strategy for multivariate qualitative analysis of food fraud.

PubMed

Márquez, Cristina; López, M Isabel; Ruisánchez, Itziar; Callao, M Pilar

2016-12-01

Two data fusion strategies (high- and mid-level) combined with a multivariate classification approach (Soft Independent Modelling of Class Analogy, SIMCA) have been applied to take advantage of the synergistic effect of the information obtained from two spectroscopic techniques: FT-Raman and NIR. Mid-level data fusion consists of merging some of the previous selected variables from the spectra obtained from each spectroscopic technique and then applying the classification technique. High-level data fusion combines the SIMCA classification results obtained individually from each spectroscopic technique. Of the possible ways to make the necessary combinations, we decided to use fuzzy aggregation connective operators. As a case study, we considered the possible adulteration of hazelnut paste with almond. Using the two-class SIMCA approach, class 1 consisted of unadulterated hazelnut samples and class 2 of samples adulterated with almond. Models performance was also studied with samples adulterated with chickpea. The results show that data fusion is an effective strategy since the performance parameters are better than the individual ones: sensitivity and specificity values between 75% and 100% for the individual techniques and between 96-100% and 88-100% for the mid- and high-level data fusion strategies, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Laboratory analyses of micron-sized solid grains: Experimental techniques and recent results

NASA Technical Reports Server (NTRS)

Colangeli, L.; Bussoletti, E.; Blanco, A.; Borghesi, A.; Fonti, S.; Orofino, V.; Schwehm, G.

1989-01-01

Morphological and spectrophotometric investigations have been extensively applied in the past years to various kinds of micron and/or submicron-sized grains formed by materials which are candidate to be present in space. The samples are produced in the laboratory and then characterized in their physio-chemical properties. Some of the most recent results obtained on various kinds of carbonaceous materials are reported. Main attention is devoted to spectroscopic results in the VUV and IR wavelength ranges, where many of the analyzed samples show typical fingerprints which can be identified also in astrophysical and cometary materials. The laboratory methodologies used so far are also critically discussed in order to point out capabilities and present limitations, in the view of possible application to returned comet samples. Suggestions are given to develop new techniques which should overcome some of the problems faced in the manipulation and analysis of micron solid samples.

Plasmonic nanoparticles for a bottom-up approach to fabricate optical metamaterials

NASA Astrophysics Data System (ADS)

Dintinger, José; Scharf, Toralf

2012-03-01

We investigate experimentally metallic nanoparticle composites fabricated by bottom-up techniques as potential candidates for optical metamaterials. Depending on the plasmonic resonances sustained by individual NPs and their nanoscale organization into larger meta-atoms, various properties might emerge. Here, the focus of our contribution is on the fabrication and optical characterization of silver NP clusters with a spherical shape. We start with the characterisation of the "bulk" dielectric constants of silver NP inks by spectroscopic ellipsometry for different nanoparticle densities (i.e from strongly diluted dispersions to solid randomly packed films). The inks are then used to prepare spherical nanoparticle clusters by an oil-in water emulsion technique. The study of their optical properties demonstrates their ability to support Mie resonances in the visible. These resonances are associated with the excitation of a magnetic dipole, which constitutes a prerequisite to the realization of metamaterials with negative permeability.

Study of structural, spectroscopic and dielectric properties of multiferroic cadmium doped Samarium manganite synthesized by solid state reaction method

NASA Astrophysics Data System (ADS)

Gupta, Vandana; Raina, Bindu; Verma, Seema; Bamzai, K. K.

2018-05-01

Samarium manganite doped with cadmium having general formula Sm1-xCdxMnO3 for x = 0.05, 0.15 were synthesized by solid state reaction technique. These compositions were characterized by various techniques like X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and dielectric. XRD analysis confirms the single phase formation with pervoskites structure having orthorhombic phase. Densities were determined and compared with the results obtained by Archimedes principle. The scanning electron micrograph shows that the particle size distribution is almost homogeneous and spherical in shape. FTIR analysis confirms the presence of various atomic bonds within a molecule. A very large value of dielectric constant was observed at low frequencies due to the presence of grains and interfaces. The dielectric constant value decreases with increase in cadmium doping at samarium site.

A vibrational spectroscopic and principal component analysis of triarylmethane dyes by comparative laboratory and portable instrumentation

NASA Astrophysics Data System (ADS)

Doherty, B.; Vagnini, M.; Dufourmantelle, K.; Sgamellotti, A.; Brunetti, B.; Miliani, C.

2014-03-01

This contribution examines the utility of vibrational spectroscopy by bench and portable Raman/surface enhanced Raman and infrared methods for the investigation of ten early triarlymethane dye powder references and dye solutions applied on paper. The complementary information afforded by the techniques is shown to play a key role in the identification of specific spectral marker ranges to distiguish early synthetic dyes of art-historical interest through the elaboration of an in-house database of modern organic dyes. Chemometric analysis has permitted a separation of data by the discrimination of di-phenyl-naphthalenes and triphenylmethanes (di-amino and tri-amino derivatives). This work serves as a prelude to the validation of a non-invasive working method for in situ characterization of these synthetic dyes through a careful comparison of respective strengths and limitations of each portable technique.

Molybdenum oxide nanocolloids prepared by an external field-assisted laser ablation in water

NASA Astrophysics Data System (ADS)

Spadaro, Salvatore; Bonsignore, Martina; Fazio, Enza; Cimino, Francesco; Speciale, Antonio; Trombetta, Domenico; Barreca, Francesco; Saija, Antonina; Neri, Fortunato

2018-01-01

he synthesis of extremely stable molybdenum oxide nanocolloids by pulsed laser ablation was studied. This green technique ensures the formation of contaminant-free nanostructures and the absence of by-products. A focused picosecond pulsed laser beam was used to ablate a solid molybdenum target immersed in deionized water. Molybdenum oxide nearly spherical nanoparticles with dimensions within few nanometers (20-100 nm) are synthesized when the ablation processes were carried out, in water, at room temperature and 80°C. The application of an external electric field during the ablation process induces a nanostructures reorganization, as indicated by Scanning-Transmission Electron Microscopy images analysis. The ablation products were also characterized by some spectroscopic techniques: conventional UV-vis optical absorption, atomic absorption, dynamic light scattering, micro-Raman and X-ray photoelectron spectroscopies. Finally, NIH/3T3 mouse fibroblasts were used to evaluate cell viability by the sulforhodamine B assay

Femtosecond stimulated Raman evidence for charge-transfer character in pentacene singlet fission.

PubMed

Hart, Stephanie M; Silva, W Ruchira; Frontiera, Renee R

2018-02-07

Singlet fission is a spin-allowed process in which an excited singlet state evolves into two triplet states. We use femtosecond stimulated Raman spectroscopy, an ultrafast vibrational technique, to follow the molecular structural evolution during singlet fission in order to determine the mechanism of this process. In crystalline pentacene, we observe the formation of an intermediate characterized by pairs of excited state peaks that are red- and blue-shifted relative to the ground state features. We hypothesize that these features arise from the formation of cationic and anionic species due to partial transfer of electron density from one pentacene molecule to a neighboring molecule. These observations provide experimental evidence for the role of states with significant charge-transfer character which facilitate the singlet fission process in pentacene. Our work both provides new insight into the singlet fission mechanism in pentacene and demonstrates the utility of structurally-sensitive time-resolved spectroscopic techniques in monitoring ultrafast processes.

Coherent Anti-Stokes Raman Spectroscopic Thermometry in a Supersonic Combustor

NASA Technical Reports Server (NTRS)

Cutler, A. D.; Danehy, P. M.; Springer, R. R.; OByrne, S.; Capriotti, D. P.; DeLoach, R.

2003-01-01

An experiment has been conducted to acquire data for the validation of computational fluid dynamics codes used in the design of supersonic combustors. The flow in a supersonic combustor, consisting of a diverging duct with a single downstream-angled wail injector, is studied. Combustor entrance Mach number is 2 and enthalpy nominally corresponds to Mach 7 flight. The primary measurement technique is coherent anti-Stokes Raman spectroscopy, but surface pressures and temperatures have also been acquired. Modern design of experiment techniques have been used to maximize the quality of the data set (for the given level of effort) and to minimize systematic errors. Temperature maps are obtained at several planes in the flow for a case in which the combustor is piloted by injecting fuel upstream of the main injector and one case in which it is not piloted. Boundary conditions and uncertainties are characterized.

Comparison of spectroscopically measured finger and forearm tissue ethanol concentration to blood and breath ethanol measurements

NASA Astrophysics Data System (ADS)

Ridder, Trent D.; Hull, Edward L.; Ver Steeg, Benjamin J.; Laaksonen, Bentley D.

2011-02-01

Previous works investigated a spectroscopic technique that offered a promising alternative to blood and breath assays for determining in vivo alcohol concentration. Although these prior works measured the dorsal forearm, we report the results of a 26-subject clinical study designed to evaluate the spectroscopic technique at a finger measurement site through comparison to contemporaneous forearm spectroscopic, venous blood, and breath measurements. Through both Monte Carlo simulation and experimental data, it is shown that tissue optical probe design has a substantial impact on the effective path-length of photons through the skin and the signal-to-noise ratio of the spectroscopic measurements. Comparison of the breath, blood, and tissue assays demonstrated significant differences in alcohol concentration that are attributable to both assay accuracy and alcohol pharmacokinetics. Similar to past works, a first order kinetic model is used to estimate the fraction of concentration variance explained by alcohol pharmacokinetics (72.6-86.7%). A significant outcome of this work was significantly improved pharmacokinetic agreement with breath (arterial) alcohol of the finger measurement (mean kArt-Fin = 0.111 min-1) relative to the forearm measurement (mean kArt-For = 0.019 min-1) that is likely due to the increased blood perfusion of the finger.

Single-pulse measurement of density and temperature in a turbulent, supersonic flow using UV laser spectroscopy

NASA Technical Reports Server (NTRS)

Fletcher, D. G.; Mckenzie, R. L.

1992-01-01

Nonintrusive measurements of density and temperature and their turbulent fluctuation levels have been obtained in the boundary layer of an unseeded, Mach 2 wind tunnel flow. The spectroscopic technique that was used to make the measurements is based on the combination of laser-induced oxygen fluorescence and Raman scattering by oxygen and nitrogen from the same laser pulse. Results from this demonstration experiment compare favorably with previous measurements obtained in the same facility from conventional probes and an earlier spectroscopic technique.

No microplastics in benthic eelpout (Zoarces viviparus): An urgent need for spectroscopic analyses in microplastic detection.

PubMed

Wesch, Charlotte; Barthel, Anne-Kathrin; Braun, Ulrike; Klein, Roland; Paulus, Martin

2016-07-01

Monitoring the ingestion of microplastics is challenging and suitable detection techniques are insufficiently used. Thus, misidentifying natural for synthetic microfibres cannot be avoided. As part of a framework to monitor the ingestion of microplastics in eelpout, this short report addresses the accurate identification of microfibres. We show that, following visual inspections, putatively synthetic microfibres are indeed of natural origin, as ascertained by spectrometric analyses. Consequently, we call for an inclusion of spectroscopic techniques in standardized microplastic monitoring schemes. Copyright © 2016 Elsevier Inc. All rights reserved.

Accurate spectroscopic characterization of oxirane: A valuable route to its identification in Titan's atmosphere and the assignment of unidentified infrared bands

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

Puzzarini, Cristina; Biczysko, Malgorzata; Bloino, Julien

2014-04-20

In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm{sup –1} for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be usefulmore » for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).« less

Multivariate curve resolution applied to kinetic-spectroscopic data matrices: Dye determination in foods by means of enzymatic oxidation.

PubMed

Boeris, Valeria; Arancibia, Juan A; Olivieri, Alejandro C

2017-07-01

In this work, the combination of chemometric techniques with kinetic-spectroscopic data allowed quantifying two dyes (tartrazine and carminic acid) in complex matrices as mustard, ketchup, asparagus soup powder, pumpkin soup powder, plum jam and orange-strawberry juice. Quantitative analysis was performed without the use of tedious sample pretreatment, due to the achievement of the second-order advantage. The results obtained showed an improvement in simplicity, speed and cost with respect to usual separation techniques, allowing to properly quantifying these dyes obtaining limits of detection below 0.6mgL -1 . In addition, to the best of our knowledge, is the first time that kinetic-spectroscopic data are obtained from the action of laccase for analytical purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

Spectroscopic and Photometric Survey of Northern Sky for the ESA PLATO space mission

NASA Astrophysics Data System (ADS)

Ženovienė, Renata; Bagdonas, Vilius; Drazdauskas, Arnas; Janulis, Rimvydas; Klebonas, Lukas; Mikolaitis, Šarūnas; Pakštienė, Erika; Tautvaišienė, Gražina

2018-04-01

The ESA-PLATO 2.0 mission will perform an in-depth analysis of the large part of the sky-sphere searching for extraterrestrial telluric-like planets. At the Molėtai Astronomical Observatory of Vilnius University, we started a spectroscopic and photometric survey of the northern sky fields that potentially will be targeted by the PLATO mission. We aim to contribute in developing the PLATO input catalogue by delivering a long-duration stellar variability information and a full spectroscopic characterization of brightest targets. First results of this survey are overviewed.

Error analysis applied to several inversion techniques used for the retrieval of middle atmospheric constituents from limb-scanning MM-wave spectroscopic measurements

NASA Technical Reports Server (NTRS)

Puliafito, E.; Bevilacqua, R.; Olivero, J.; Degenhardt, W.

1992-01-01

The formal retrieval error analysis of Rodgers (1990) allows the quantitative determination of such retrieval properties as measurement error sensitivity, resolution, and inversion bias. This technique was applied to five numerical inversion techniques and two nonlinear iterative techniques used for the retrieval of middle atmospheric constituent concentrations from limb-scanning millimeter-wave spectroscopic measurements. It is found that the iterative methods have better vertical resolution, but are slightly more sensitive to measurement error than constrained matrix methods. The iterative methods converge to the exact solution, whereas two of the matrix methods under consideration have an explicit constraint, the sensitivity of the solution to the a priori profile. Tradeoffs of these retrieval characteristics are presented.

Dual functionalized graphene oxide serves as a carrier for delivering oligohistidine- and biotin-tagged biomolecules into cells.

PubMed

Jana, Batakrishna; Mondal, Goutam; Biswas, Atanu; Chakraborty, Indrani; Saha, Abhijit; Kurkute, Prashant; Ghosh, Surajit

2013-11-01

A versatile method of dual chemical functionalization of graphene oxide (GO) with Tris-[nitrilotris(acetic acid)] (Tris-NTA) and biotin for cellular delivery of oligohistidine- and biotin-tagged biomolecules is reported. Orthogonally functionalized GO surfaces with Tris-NTA and biotin to obtain a dual-functionalized GO (DFGO) are prepared and characterized by various spectroscopic and microscopic techniques. Fluorescence microscopic images reveal that DFGO surfaces are capable of binding oligohistidine-tagged biomolecules/proteins and avidin/biotin-tagged biomolecules/proteins orthogonally. The DFGO nanoparticles are non-cytotoxic in nature and can deliver oligohistidine- and biotin-tagged biomolecules simultaneously into the cell. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, analytical analysis, and medicinal aspect of novel benzimidazoles and their metal complexes.

PubMed

Agrawal, Sangeeta; Bhatnagar, Rishi Raj; Tiwari, Anjani; Srivastava, Rakesh; Sharma, Upasana

2013-11-01

Benzimidazole and their metal analogs that can act as multimodal agent and have non-peptidic CCK-B receptor antagonist were synthesized and characterized on the basis of spectroscopic techniques such as FT-IR, NMR, FAB-MS and also evaluated for biologic efficacy. The ligands showed binding to most of the organs, known to express CCK receptors in biodistribution studies. Cholecystokinin (CCK1 and CCK2) receptor binding affinities of these analogs (IC50) are 0.802 ± 0.007 for compound C and 0.326 ± 0.012 for compound D in rat pancreatic acini. These studies have provided a new template for further development of novel agents for various related diseases.

Deposition of amorphous carbon thin films by aerosol-assisted CVD method

NASA Astrophysics Data System (ADS)

Fadzilah, A. N.; Dayana, K.; Rusop, M.

2018-05-01

This paper reports on the deposition of amorphous carbon (a-C) by Aerosol-assisted Chemical Vapor Deposition (AACVD) using natural source of camphor oil as the precursor material. 4 samples were deposited at 4 different deposition flow rate from 15 sccm to 20 sccm, with 5 sccm interval for each sample. The analysis includes the electrical, optical and structural analysis of the data. The a-C structure which came from the manipulation of synthesis parameter was characterized by the solar simulator system, UV-VIS-NIR, Raman spectroscope and AFM. The properties of a-C are highly dependent on the deposition techniques and deposition parameters; hence the influences of gas flow rate were studied.

Nanostructured magnesium oxide biosensing platform for cholera detection

NASA Astrophysics Data System (ADS)

Patel, Manoj K.; Azahar Ali, Md.; Agrawal, Ved V.; Ansari, Z. A.; Ansari, S. G.; Malhotra, B. D.

2013-04-01

We report fabrication of highly crystalline nanostructured magnesium oxide (NanoMgO, size >30 nm) film electrophoretically deposited onto indium-tin-oxide (ITO) glass substrate for Vibrio cholerae detection. The single stranded deoxyribonucleic acid (ssDNA) probe, consisting of 23 bases (O1 gene sequence) immobilized onto NanoMgO/ITO electrode surface, has been characterized using electrochemical, Fourier Transform-Infra Red, and UltraViolet-visible spectroscopic techniques. The hybridization studies of ssDNA/NanoMgO/ITO bioelectrode with fragmented target DNA conducted using differential pulse voltammetry reveal sensitivity as 16.80 nA/ng/cm2, response time of 3 s, linearity as 100-500 ng/μL, and stability of about 120 days.

Synthesis of fluorescent carbon dots by a microwave heating process: structural characterization and cell imaging applications

NASA Astrophysics Data System (ADS)

Stefanakis, Dimitrios; Philippidis, Aggelos; Sygellou, Labrini; Filippidis, George; Ghanotakis, Demetrios; Anglos, Demetrios

2014-10-01

Two types of highly fluorescent carbon dots (C-dots) were prepared by a single-step procedure based on microwave heating citric acid and 6-aminocaproic acid or citric acid and urea in an aqueous solution. The small size of the isolated carbon dots along with their strong absorption in the UV and their excitation wavelength-dependent fluorescence render them ideal nanomaterials for biomedical applications (imaging and sensing). The structure and properties of the two types of C-dot materials were studied using a series of spectroscopic techniques. The ability of the C-dots to be internalized by HeLa cells was demonstrated via 3-photon fluorescence microscopy imaging.

Preparation, linear and NLO properties of DNA-CTMA-SBE complexes

NASA Astrophysics Data System (ADS)

Manea, Ana-Maria; Rau, Ileana; Kajzar, Francois; Meghea, Aurelia

2013-10-01

Synthesis of deoxyribonucleic acid (DNA) - was cetyltrimethylammonium (CTMA) - sea buckthorn extract (SBE) at different concentrations is decribed. The complexes were processed into good optical quality thin films by spin coating on different substrates such as: glass, silica and ITO covered glass substrates. SBE contains many bioactive substances that can be used in the treatment of several diseases, such as cardiovascular disease, cancer, and acute mountain sickness. The obtained thin films were characterized for their spectroscopic, fluorescent, linear and nonlinear optical properties as function of SBE concentration. The third-order nonlinear optical (NLO) properties of thin films were determined by the optical third-harmonic generation technique at 1 064.2 nm fundamental wavelength.

From Single Atoms to Nanoparticles — Spectroscopy on the Atomic Level

NASA Astrophysics Data System (ADS)

Nilius, Niklas

2003-12-01

The scanning tunneling microscope is not only a well-established tool for a topographic characterization of the sample surface on the atomic scale. It also provides a variety of spectroscopic techniques to examine electronic, magnetic, vibrational and optical properties of a localized system. The following presentation gives an overview, how scanning tunneling spectroscopy, inelastic electron tunneling spectroscopy and photon emission spectroscopy with the STM can be employed to investigate spatially confined metal systems and their interaction with molecular gases. The experiments were performed on single Pd and Au atoms, mono-atomic chains and individual Ag clusters on a NiAl support and a Al2O3 thin film.

Synthesis of embedded titanium dioxide nanoparticles by oxygen ion implantation in titanium films

NASA Astrophysics Data System (ADS)

Rukade, Deepti. A.; Desai, C. A.; Kulkarni, Nilesh; Tribedi, L. C.; Bhattacharyya, Varsha

2013-02-01

Thin films of titanium of 100nm thickness are deposited on fused silica substrates. These films are implanted by oxygen ions with implantation energy of 60keV obtained from ECR based highly charged ion accelerator. The implanted films are later annealed in a tube furnace to establish nanophase formation. The post implanted annealed films are characterized by UV-Visible Spectroscopy and Glancing Angle X-ray Diffraction technique (GAXRD). The phase formed and particle size is determined by GAXRD. Nanoparticle formation is confirmed by the UV-VIS spectroscopic analysis that shows quantum size effects in the form of a blue shift in the band-gap energy of titanium-oxide.

New 1-indanone thiosemicarbazone derivatives active against BVDV.

PubMed

Finkielsztein, Liliana M; Castro, Eliana F; Fabián, Lucas E; Moltrasio, Graciela Y; Campos, Rodolfo H; Cavallaro, Lucía V; Moglioni, Albertina G

2008-08-01

Identification of new therapeutic agents for the treatment of viral diseases represents an area of active investigation. In an effort to develop new antiviral compounds, a series of 1-indanone thiosemicarbazone derivatives were synthesized. These derivatives were structurally characterized using several spectroscopic techniques and evaluated against bovine viral diarrhoea virus as a surrogate model for hepatitis C virus. Thiosemicarbazone 2m showed potent anti-bovine viral diarrhoea virus activity with a higher selectivity index (SI=80.29) than that of ribavirin (SI=11.64). This result determines the potentiality of these thiosemicarbazones as antiviral agents for the treatment of infections caused by other highly related members of Flaviviridae family, as hepatitis C virus.

Free-radical sensing by using naphthalimide based mesoporous silica (MCM-41) nanoparticles: A combined fluorescence and cellular imaging study

NASA Astrophysics Data System (ADS)

Jha, Gaurav; Roy, Subhasis; Sahu, Prabhat Kumar; Banerjee, Somnath; Anoop, N.; Rahaman, Abdur; Sarkar, Moloy

2018-01-01

Keeping in mind the advantages of material-based systems over simple molecule-based systems, we have designed and developed three inorganic-organic hybrid systems by anchoring 1,8-naphthalimide derivatives to mesoporous silica nanoparticles for detection of free radicals. Prior to photophysical study, systems are characterized by spectroscopic, microscopic and thermo-gravimetric techniques. Steady state and time-resolved fluorescence studies demonstrate that the hydrazine based system is senstive towards detection of various free radicals. Cellular imaging study reveals cell permeability and toxicity study demonstrates the non-toxic nature of the material. These studies have suggested that present system has the potential to be used in various biological applications.

High-energy cryo x-ray nano-imaging at the ID16A beamline of ESRF

NASA Astrophysics Data System (ADS)

da Silva, Julio C.; Pacureanu, Alexandra; Yang, Yang; Fus, Florin; Hubert, Maxime; Bloch, Leonid; Salome, Murielle; Bohic, Sylvain; Cloetens, Peter

2017-09-01

The ID16A beamline at ESRF offers unique capabilities for X-ray nano-imaging, and currently produces the worlds brightest high energy diffraction-limited nanofocus. Such a nanoprobe was designed for quantitative characterization of the morphology and the elemental composition of specimens at both room and cryogenic temperatures. Billions of photons per second can be delivered in a diffraction-limited focus spot size down to 13 nm. Coherent X-ray imaging techniques, as magnified holographic-tomography and ptychographic-tomography, are implemented as well as X-ray fluorescence nanoscopy. We will show the latest developments in coherent and spectroscopic X-ray nanoimaging implemented at the ID16A beamline

Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses.

PubMed

Ramteke, D D; Gedam, R S

2014-12-10

27.5 Li2O-(72.5-X) B2O3-X Sm2O3 (X=0.5, 1, 1.5 and 2) were prepared by conventional melt quench technique. Impedance spectroscopy (IS) is used to study the electrical properties of these prepared glasses. Modulus formalism is introduced to study relaxation behaviour of these glasses. Scaling model shows the good overlap of data on single master curve which suggests that conduction mechanism in these glasses is compositional dependent. Variation of dielectric constant and dielectric loss with the addition of Sm2O3 and frequency are discussed here. Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetic nanoparticle supported phosphotungstic acid: An efficient catalyst for the synthesis of xanthene derivatives

NASA Astrophysics Data System (ADS)

Patel, Nipun; Katheriya, Deepak; Dadhania, Harsh; Dadhania, Abhishek

2018-05-01

Magnetic nanoparticle supported phosphotungstic acid (Fe3O4@SiO2-HPW) was applied as a highly efficient catalyst for the synthesis of 14H-dibenzoxanthene derivatives via condensation reaction of 2-naphthol and aryl aldehydes. The catalyst was found highly efficient for the synthesis of xanthene derivatives under solvent free condition. The catalyst showed high activity and stability during the reaction and provided excellent yield of the corresponding products in short reaction time. All the synthesized compounds were characterized through FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Furthermore, the catalyst is magnetically recoverable and can be reused several times without significant loss of its catalytic activity.

Spectroscopic Characterization of Key Aromatic and Heterocyclic Molecules: A Route toward the Origin of Life

NASA Astrophysics Data System (ADS)

Puzzarini, Cristina; Baiardi, Alberto; Bloino, Julien; Barone, Vincenzo; Murphy, Thomas E.; Drew, H. Dennis; Ali, Ashraf

2017-09-01

To gain information on the abiotic synthesis of the building blocks of life from simple molecules, and their subsequent chemical evolution to biological systems, the starting point is the identification of target species in Titan-like planets; I.e., planets that resemble the primitive Earth, as well as in Earth-like planets in the habitable zone of their star, namely planets where life can be already originated. In this scenario, molecular spectroscopy plays a crucial role because spectroscopic signatures are at the basis of an unequivocal proof for the presence of these target molecules. Thanks to advances in many different techniques and NASA’s successful Kepler exoplanet transit mission, thousands of diverse planets outside of our solar system have been discovered. The James Webb Space Telescope (JWST), scheduled to be launched in 2018, will be very helpful in the identification of biosignature gases in Earth-like planets’ atmospheres and prebiotic molecule signatures in Titan-like atmospheres, by observing their absorption during transits. Although the search for key-target molecules in exoplanet atmospheres can be carried out by the JWST Transit Spectroscopy in the infrared (IR) region (0.6-29 μm wavelength range), opportunities for their detection in protostellar cores, protoplanetary disks, and on Titan are also offered by interferometric high spectral and spatial resolution observations using the Atacama Large Millimeter/submillimeter Array. In the present work, target molecules have been selected, and their spectroscopic characterization presented in view of supporting their infrared and complementary millimeter/submillimeter-wave spectral observations. In detail, the selected target molecules include: (1) the three-membered oxygen-containing heterocycles, oxirane and protonated oxirane; (2) the cyclopropenyl cation and its methyl derivative; (3) two examples of ortho- and peri-fused tri-cyclic aromatic rings, I.e., the phenalenyl cation ({{{C}}}13{{{{H}}}9}+) and anion ({{{C}}}13{{{{H}}}9}-); and (4) uracil, a specific RNA base.

Spectroscopic Characterization of Key Aromatic Molecules: A Route toward The Origin of Life.

PubMed

Puzzarini, Cristina; Baiardi, Alberto; Bloino, Julien; Barone, Vincenzo; Murphy, Thomas E; Drew, Dennis; Ali, Ashraf

2017-08-04

To gain information on the abiotic synthesis of the building blocks of life from simple molecules, and their subsequent chemical evolution to biological systems, the starting point is the identification of target species in Titan-like planets, i.e., planets that resemble the primitive Earth, as well as in Earth-like planets in the habitable zone of their star, namely planets where life can be already originated. In this scenario, molecular spectroscopy plays a crucial role because spectroscopic signatures are at the basis of an unequivocal proof for the presence of these target molecules. Thanks to the advances in many different techniques and to the NASA successful Kepler exoplanet transit mission, thousands of diverse planets outside of our solar system have been discovered. The James Webb Space Telescope (JWST), scheduled to be launched in 2018, will be very helpful in the identification of biosignature gases in Earth-like planets' atmospheres and of prebiotic molecule signatures in Titan-like atmospheres by observing their absorption during transits. While the search for key-target molecules in exoplanet atmospheres can be carried out by the JWST Transit Spectroscopy in the infrared (IR) region (0.6 - 29 µm wavelength range), opportunities for their detection in protostellar cores, protoplanetary disks and on Titan are also offered by the interferometric high spectral and spatial resolution observations using the Atacama Large Millimeter/submillimeter Array (ALMA). In the present work, target molecules have been selected and their spectroscopic characterization presented in view of supporting their infrared and complementary millimeter/submillimeter-wave spectral observations. In detail, the selected target molecules include: (1) the three-membered oxygen-containing heterocycles: oxirane and protonated oxirane, (2) the cyclopropenyl cation and its methyl derivative, (3) two examples of ortho- and peri-fused tri-cyclic aromatic rings, i.e., the phenalenyl cation (C 13 H 9 + ) and anion (C 13 H 9 -), and (4) uracil, a specific RNA base.

The role of chromatographic and chiroptical spectroscopic techniques and methodologies in support of drug discovery for atropisomeric drug inhibitors of Bruton's tyrosine kinase.

PubMed

Dai, Jun; Wang, Chunlei; Traeger, Sarah C; Discenza, Lorell; Obermeier, Mary T; Tymiak, Adrienne A; Zhang, Yingru

2017-03-03

Atropisomers are stereoisomers resulting from hindered bond rotation. From synthesis of pure atropisomers, characterization of their interconversion thermodynamics to investigation of biological stereoselectivity, the evaluation of drug candidates subject to atropisomerism creates special challenges and can be complicated in both early drug discovery and later drug development. In this paper, we demonstrate an array of analytical techniques and systematic approaches to study the atropisomerism of drug molecules to meet these challenges. Using a case study of Bruton's tyrosine kinase (BTK) inhibitor drug candidates at Bristol-Myers Squibb, we present the analytical strategies and methodologies used during drug discovery including the detection of atropisomers, the determination of their relative composition, the identification of relative chirality, the isolation of individual atropisomers, the evaluation of interconversion kinetics, and the characterization of chiral stability in the solid state and in solution. In vivo and in vitro stereo-stability and stereo-selectivity were investigated as well as the pharmacological significance of any changes in atropisomer ratios. Techniques applied in these studies include analytical and preparative enantioselective supercritical fluid chromatography (SFC), enantioselective high performance liquid chromatography (HPLC), circular dichroism (CD), and mass spectrometry (MS). Our experience illustrates how atropisomerism can be a very complicated issue in drug discovery and why a thorough understanding of this phenomenon is necessary to provide guidance for pharmaceutical development. Analytical techniques and methodologies facilitate key decisions during the discovery of atropisomeric drug candidates by characterizing time-dependent physicochemical properties that can have significant biological implications and relevance to pharmaceutical development plans. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic characterization (FT-IR, FT-Raman, and NMR), quantum chemical studies and molecular docking of 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione.

PubMed

Avdović, Edina H; Milenković, Dejan; Dimitrić Marković, Jasmina M; Đorović, Jelena; Vuković, Nenad; Vukić, Milena D; Jevtić, Verica V; Trifunović, Srećko R; Potočňák, Ivan; Marković, Zoran

2018-04-15

The experimental and theoretical investigations of structure of the 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione were performed. X-ray structure analysis and spectroscopic methods (FTIR and FT-Raman, 1 H and 13 C NMR), along with the density functional theory calculations (B3LYP functional with empirical dispersion corrections D3BJ in combination with the 6-311 + G(d,p) basis set), were used in order to characterize the molecular structure and spectroscopic behavior of the investigated coumarin derivative. Molecular docking analysis was carried out to identify the potency of inhibition of the title molecule against human's Ubiquinol-Cytochrome C Reductase Binding Protein (UQCRB) and Methylenetetrahydrofolate reductase (MTHFR). The inhibition activity was obtained for ten conformations of ligand inside the proteins. Copyright © 2018 Elsevier B.V. All rights reserved.

Pharmaceutical properties of two ethenzamide-gentisic acid cocrystal polymorphs: Drug release profiles, spectroscopic studies and theoretical calculations.

PubMed

Sokal, Agnieszka; Pindelska, Edyta; Szeleszczuk, Lukasz; Kolodziejski, Waclaw

2017-04-30

The aim of this study was to evaluate the stability and solubility of the polymorphic forms of the ethenzamide (ET) - gentisic acid (GA) cocrystals during standard technological processes leading to tablet formation, such as compression and excipient addition. In this work two polymorphic forms of pharmaceutical cocrystals (ETGA) were characterized by 13 C and 15 N solid-state nuclear magnetic resonance and Fourier transformed infrared spectroscopy. Spectroscopic studies were supported by gauge including projector augmented wave (GIPAW) calculations of chemical shielding constants.Polymorphs of cocrystals were easily identified and characterized on the basis of solid-state spectroscopic studies. ETGA cocrystals behaviour during direct compressionand tabletting with excipient addition were tested. In order to choose the best tablet composition with suitable properties for the pharmaceutical industry dissolution profile studies of tablets containing polymorphic forms of cocrystals with selected excipients were carried out. Copyright © 2017. Published by Elsevier B.V.

The Exoplanet Characterization ToolKit (ExoCTK)

NASA Astrophysics Data System (ADS)

Stevenson, Kevin; Fowler, Julia; Lewis, Nikole K.; Fraine, Jonathan; Pueyo, Laurent; Valenti, Jeff; Bruno, Giovanni; Filippazzo, Joseph; Hill, Matthew; Batalha, Natasha E.; Bushra, Rafia

2018-01-01

The success of exoplanet characterization depends critically on a patchwork of analysis tools and spectroscopic libraries that currently require extensive development and lack a centralized support system. Due to the complexity of spectroscopic analyses and initial time commitment required to become productive, there are currently a limited number of teams that are actively advancing the field. New teams with significant expertise, but without the proper tools, face prohibitively steep hills to climb before they can contribute. As a solution, we are developing an open-source, modular data analysis package in Python and a publicly facing web interface focused primarily on atmospheric characterization of exoplanets and exoplanet transit observation planning with JWST. The foundation of these software tools and libraries exist within pockets of the exoplanet community. Our project will gather these seedling tools and grow a robust, uniform, and well maintained exoplanet characterization toolkit.

Nondestructive characterization of textured a-Si:H/c-Si heterojunction solar cell structures with nanometer-scale a-Si:H and In2O3:Sn layers by spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Matsuki, Nobuyuki; Fujiwara, Hiroyuki

2013-07-01

Nanometer-scale hydrogenated amorphous silicon (a-Si:H) layers formed on crystalline silicon (c-Si) with pyramid-shaped textures have been characterized by spectroscopic ellipsometry (SE) using a tilt angle measurement configuration, in an attempt to establish a nondestructive method for the structural characterization of the a-Si:H/c-Si heterojunction solar cells. By applying an a-Si:H dielectric function model developed recently, the thickness and SiH2 content of the a-Si:H layer have been determined even on the textured substrates. Furthermore, from the SE analysis incorporating the Drude model, the carrier properties of the In2O3:Sn layers in the textured solar-cell structure have been characterized.

Hyperspectral laser-induced autofluorescence imaging of dental caries

NASA Astrophysics Data System (ADS)

Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

2012-01-01

Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentine and pulp. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Laser induced autofluorescence was shown to be a useful method for early detection of demineralization. The existing studies involved either a single point spectroscopic measurements or imaging at a single spectral band. In the case of spectroscopic measurements, very little or no spatial information is acquired and the measured autofluorescence signal strongly depends on the position and orientation of the probe. On the other hand, single-band spectral imaging can be substantially affected by local spectral artefacts. Such effects can significantly interfere with automated methods for detection of early caries lesions. In contrast, hyperspectral imaging effectively combines the spatial information of imaging methods with the spectral information of spectroscopic methods providing excellent basis for development of robust and reliable algorithms for automated classification and analysis of hard dental tissues. In this paper, we employ 405 nm laser excitation of natural caries lesions. The fluorescence signal is acquired by a state-of-the-art hyperspectral imaging system consisting of a high-resolution acousto-optic tunable filter (AOTF) and a highly sensitive Scientific CMOS camera in the spectral range from 550 nm to 800 nm. The results are compared to the contrast obtained by near-infrared hyperspectral imaging technique employed in the existing studies on early detection of dental caries.

Combination of multi-scale and multi-edge X-ray spectroscopy for investigating the products obtained from the interaction between kaolinite and metallic iron in anoxic conditions at 90 °C

NASA Astrophysics Data System (ADS)

Rivard, Camille; Montargès-Pelletier, Emmanuelle; Vantelon, Delphine; Pelletier, Manuel; Karunakaran, Chithra; Michot, Laurent J.; Villieras, Frédéric; Michau, Nicolas

2013-02-01

In the context of radioactive waste repository in geological formation, kaolinite-metallic iron interaction in chlorine solution was conducted in batch experiments, under anoxic conditions at 90 °C during 9 months. After a mineralogical characterization at a global scale, products were analyzed at the micrometer and nanometer scales by X-ray absorption spectroscopic techniques (XAS and STXM). Absorption at Al, Si and Fe edges was investigated to have a complete overview of the distribution and status of constituting elements. Whereas Si K-edge results do not evidence significant evolution of silicon status, investigations at Al K-edge and Fe L-edges demonstrate variations at aggregate and particle scales of IVAl:VIAl and Fe2+:Fe3+ ratios. Spectroscopic data evidence the systematic crystallization of Fe-serpentines onto the remaining particles of kaolinite and the absence of pure species (kaolinite or Fe-serpentines). Combination of spatially resolved spectroscopic analyses and TEM-EDXS elemental distribution aims to calculate unit cell formulae of Fe-serpentines layers and abundance of each species in mixed particles. For most of the investigated particles, results reveal that the variations of particles composition are directly linked to the relative contributions of kaolinite and Fe-berthierine in mixed particles. However, for some particles, microscale investigations evidence crystallization of two other Fe-serpentines species, devoid of aluminum, cronstedtite and greenalite.

Optical coherence tomography spectral analysis for detecting apoptosis in vitro and in vivo

NASA Astrophysics Data System (ADS)

Farhat, Golnaz; Giles, Anoja; Kolios, Michael C.; Czarnota, Gregory J.

2015-12-01

Apoptosis is a form of programmed cell death characterized by a series of predictable morphological changes at the subcellular level, which modify the light-scattering properties of cells. We present a spectroscopic optical coherence tomography (OCT) technique to detect changes in subcellular morphology related to apoptosis in vitro and in vivo. OCT data were acquired from acute myeloid leukemia (AML) cells treated with cisplatin over a 48-h period. The backscatter spectrum of the OCT signal acquired from the cell samples was characterized by calculating its in vitro integrated backscatter (IB) and spectral slope (SS). The IB increased with treatment duration, while the SS decreased, with the most significant changes occurring after 24 to 48 h of treatment. These changes coincided with striking morphological transformations in the cells and their nuclei. Similar trends in the spectral parameter values were observed in vivo in solid tumors grown from AML cells in mice, which were treated with chemotherapy and radiation. Our results provide a strong foundation from which future experiments may be designed to further understand the effect of cellular morphology and kinetics of apoptosis on the OCT signal and demonstrate the feasibility of using this technique in vivo.

Identifying Multiple Populations in M71 using CN

NASA Astrophysics Data System (ADS)

Gerber, Jeffrey M.; Friel, Eileen D.; Vesperini, Enrico

2018-01-01

It is now well established that globular clusters (GCs) host multiple stellar populations characterized by differences in several light elements. While these populations have been found in nearly all GCs, we still lack an entirely successful model to explain their formation. A key constraint to these models is the detailed pattern of light element abundances seen among the populations; different techniques for identifying these populations probe different elements and do not always yield the same results. We study a large sample of stars in the GC M71 for light elements C and N, using the CN and CH band strength to identify multiple populations. Our measurements come from low-resolution spectroscopy obtained with the WIYN-3.5m telescope for ~150 stars from the tip of the red-giant branch down to the main-sequence turn-off. The large number of stars and broad spatial coverage of our sample (out to ~3.5 half-light radii) allows us to carry out a comprehensive characterization of the multiple populations in M71. We use a combination of the various spectroscopic and photometric indicators to draw a more complete picture of the properties of the populations and to investigate the consistency of classifications using different techniques.

Structural Characterization of Lignin during Pinus taeda Wood Treatment with Ceriporiopsis subvermispora

PubMed Central

Guerra, Anderson; Mendonça, Régis; Ferraz, André; Lu, Fachuang; Ralph, John

2004-01-01

Pinus taeda wood chips were biotreated with Ceriporiopsis subvermispora under solid-state fermentation for periods varying from 15 to 90 days. Milled wood lignins extracted from sound and biotreated wood samples were characterized by wet-chemical and spectroscopic techniques. Treatment of the lignins by derivatization followed by reductive cleavage (DFRC) made it possible to detect DFRC monomers and dimers that are diagnostic of the occurrence of arylglycerol-β-O-aryl and β-β, β-5, β-1, and 4-O-5 units in the lignin structure. Quantification of these DFRC products indicated that β-O-aryl cleavage was a significant route for lignin biodegradation but that β-β, β-5, β-1, and 4-O-5 linkages were more resistant to the biological attack. The amount of aromatic hydroxyls did not increase with the split of β-O-4 linkages, suggesting that the β-O-4 cleavage products remain as quinone-type structures as detected by UV and visible spectroscopy. Nuclear magnetic resonance techniques also indicated the formation of new substructures containing nonoxygenated, saturated aliphatic carbons (CH2 and CH3) in the side chains of lignins extracted from biotreated wood samples. PMID:15240285

Application of a new non-linear least squares velocity curve analysis technique for spectroscopic binary stars

NASA Astrophysics Data System (ADS)

Karami, K.; Mohebi, R.; Soltanzadeh, M. M.

2008-11-01

Using measured radial velocity data of nine double lined spectroscopic binary systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via the method introduced by Karami and Mohebi (Chin. J. Astron. Astrophys. 7:558, 2007a) and Karami and Teimoorinia (Astrophys. Space Sci. 311:435, 2007). Our numerical results are in good agreement with those obtained by others using more traditional methods.

Infrared spectroscopic imaging for noninvasive detection of latent fingerprints.

PubMed

Crane, Nicole J; Bartick, Edward G; Perlman, Rebecca Schwartz; Huffman, Scott

2007-01-01

The capability of Fourier transform infrared (FTIR) spectroscopic imaging to provide detailed images of unprocessed latent fingerprints while also preserving important trace evidence is demonstrated. Unprocessed fingerprints were developed on various porous and nonporous substrates. Data-processing methods used to extract the latent fingerprint ridge pattern from the background material included basic infrared spectroscopic band intensities, addition and subtraction of band intensity measurements, principal components analysis (PCA) and calculation of second derivative band intensities, as well as combinations of these various techniques. Additionally, trace evidence within the fingerprints was recovered and identified.

Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation.

PubMed

Lee, Joonsup; Wen, Beryl; Carter, Elizabeth A; Combes, Valery; Grau, Georges E R; Lay, Peter A

2017-07-01

Microvesicles (MVs) are involved in cell-cell interactions, including disease pathogenesis. Nondestructive Fourier-transform infrared (FTIR) spectra from MVs were assessed as a technique to provide new biochemical insights into a LPS-induced monocyte model of septic shock. FTIR spectroscopy provided a quick method to investigate relative differences in biomolecular content of different MV populations that was complementary to traditional semiquantitative omics approaches, with which it is difficult to provide information on relative changes between classes (proteins, lipids, nucleic acids, carbohydrates) or protein conformations. Time-dependent changes were detected in biomolecular contents of MVs and in the monocytes from which they were released. Differences in phosphatidylcholine and phosphatidylserine contents were observed in MVs released under stimulation, and higher relative concentrations of RNA and α-helical structured proteins were present in stimulated MVs compared with MVs from resting cells. FTIR spectra of stimulated monocytes displayed changes that were consistent with those observed in the corresponding MVs they released. LPS-stimulated monocytes had reduced concentrations of nucleic acids, α-helical structured proteins, and phosphatidylcholine compared with resting monocytes but had an increase in total lipids. FTIR spectra of MV biomolecular content will be important in shedding new light on the mechanisms of MVs and the different roles they play in physiology and disease pathogenesis.-Lee, J., Wen, B., Carter, E. A., Combes, V., Grau, G. E. R., Lay, P. A. Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation. © FASEB.

Effect of the star formation histories on the SFR-M∗ relation at z ≥ 2

NASA Astrophysics Data System (ADS)

Cassarà, L. P.; Maccagni, D.; Garilli, B.; Scodeggio, M.; Thomas, R.; Le Fèvre, O.; Zamorani, G.; Schaerer, D.; Lemaux, B. C.; Cassata, P.; Le Brun, V.; Pentericci, L.; Tasca, L. A. M.; Vanzella, E.; Zucca, E.; Amorín, R.; Bardelli, S.; Castellano, M.; Cimatti, A.; Cucciati, O.; Durkalec, A.; Fontana, A.; Giavalisco, M.; Grazian, A.; Hathi, N. P.; Ilbert, O.; Paltani, S.; Ribeiro, B.; Sommariva, V.; Talia, M.; Tresse, L.; Vergani, D.; Capak, P.; Charlot, S.; Contini, T.; de la Torre, S.; Dunlop, J.; Fotopoulou, S.; Guaita, L.; Koekemoer, A.; López-Sanjuan, C.; Mellier, Y.; Pforr, J.; Salvato, M.; Scoville, N.; Taniguchi, Y.; Wang, P. W.

2016-08-01

We investigate the effect of different star formation histories (SFHs) on the relation between stellar mass (M∗) and star formation rate (SFR) using a sample of galaxies with reliable spectroscopic redshift zspec> 2 drawn from the VIMOS Ultra-Deep Survey (VUDS). We produce an extensive database of dusty model galaxies, calculated starting from a new library of single stellar population (SSPs) models, weighted by a set of 28 different star formation histories based on the Schmidt function, and characterized by different ratios of the gas infall timescale τinfall to the star formation efficiency ν. Dust extinction and re-emission were treated by means of the radiative transfer calculation. The spectral energy distribution (SED) fitting technique was performed by using GOSSIP+, a tool able to combine both photometric and spectroscopic information to extract the best value of the physical quantities of interest, and to consider the intergalactic medium (IGM) attenuation as a free parameter. We find that the main contribution to the scatter observed in the SFR-M∗ plane is the possibility of choosing between different families of SFHs in the SED fitting procedure, while the redshift range plays a minor role. The majority of the galaxies, at all cosmic times, are best fit by models with SFHs characterized by a high τinfall/ν ratio. We discuss the reliability of a low percentage of dusty and highly star-forming galaxies in the context of their detection in the far infrared (FIR).

Synthesis, characterization, crystal structure and quantum chemical investigations of three novel coumarin-benzenesulfonohydrazide derivatives

NASA Astrophysics Data System (ADS)

Chethan Prathap, K. N.; Lokanath, N. K.

2018-04-01

Coumarin derivatives are an important class of heterocyclic compounds due to their physical and biological properties. Coumarin derivatives have been identified with many significant electro-optical properties and biological activities. Three novel coumarin derivatives containing benzene sulfonohydrazide group were synthesized by condensation reaction. The synthesized compounds were characterized by various spectroscopic techniques (Mass, 1H/13C NMR and FTIR). Thermal and optical properties were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and UV-Vis spectroscopic studies. Finally their structures were confirmed by single crystal X-ray diffraction (XRD) studies. The three compounds exhibit diverse intermolecular interactions, as observed by the crystal packing and Hirshfeld surface analysis. Further, their structures were optimized by density functional theory (DFT) calculations using B3LYP hybrid functionals with 6-311G+(d,p) level basis set. The Mulliken charge, molecular electrostatic potential (MEP), frontier molecular orbitals (HOMO-LUMO) were investigated. The experimentally determined parameters were compared with those calculated theoretically and they complement each other with a very good correlation. The transitions among the molecular orbitals were investigated using time-dependent density functional theory (TD-DFT) and the electronic absorption spectra obtained showed very good agreement with the experimentally measured UV-Vis spectra. Furthermore, non-linear optical (NLO) properties were investigated by calculating polarizabilities and hyperpolarizabilities. All three compounds exhibit significantly high hyperpolarizabilities compared to the reference material urea, which makes them potential candidates for NLO applications.

In Situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries

DOE PAGES

Wang, Ziying; Santhanagopalan, Dhamodaran; Zhang, Wei; ...

2016-05-03

Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode–solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. In this paper, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situmore » conditions. Using a LiCoO 2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO 2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. These findings suggest that the mechanism of interfacial impedance at the LiCoO 2/LiPON interface is caused by chemical changes rather than space charge effects. Finally, insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.« less

Synthesis, spectroscopic characterization, first order nonlinear optical properties and DFT calculations of novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 1,3-diphenyl-4-phenylazo-5-pyrazolone ligand

NASA Astrophysics Data System (ADS)

Abdel-Latif, Samir A.; Mohamed, Adel A.

2018-02-01

Novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions with 1,3-diphenyl-4-phenylazo-5-pyrazolone (L) have been prepared and characterized using different analytical and spectroscopic techniques. 1:1 Complexes of Mn(II), Co(II) and Zn(II) are distorted octahedral whereas Ni(II) complex is square planar and Cu(II) is distorted trigonal bipyramid. 1:2 Complexes of Mn(II), Co(II), Cu(II) and Zn(II) are distorted trigonal bipyramid whereas Ni(II) complex is distorted tetrahedral. All complexes behave as non-ionic in dimethyl formamide (DMF). The electronic structure and nonlinear optical parameters (NLO) of the complexes were investigated theoretically at the B3LYP/GEN level of theory. Molecular stability and bond strengths have been investigated by applying natural bond orbital (NBO) analysis. The geometries of the studied complexes are non-planner. DFT calculations have been also carried out to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The calculated small energy gap between HOMO and LUMO energies shows that the charge transfer occurs within the complexes. The total static dipole moment (μtot), the mean polarizability (<α>), the anisotropy of the polarizability (Δα) and the mean first-order hyperpolarizability (<β>) were calculated and compared with urea as a reference material. The complexes show implying optical properties.

Surface analytical characterization of Streptavidin/poly(3-hexylthiophene) bilayers for bio-electronic applications

NASA Astrophysics Data System (ADS)

Sportelli, M. C.; Picca, R. A.; Manoli, K.; Re, M.; Pesce, E.; Tapfer, L.; Di Franco, C.; Cioffi, N.; Torsi, L.

2017-10-01

The analytical performance of bioelectronic devices is highly influenced by their fabrication methods. In particular, the final architecture of field-effect transistor biosensors combining spin-cast poly(3-hexylthiophene) (P3HT) film and a biomolecule interlayer deposited on a SiO2/Si substrate can lead to the development of highly performing sensing systems, such as for the case of streptavidin (SA) used for biotin sensing. To gain a better understanding of the quality of the interfacial area, critical is the assessment of the morphological features characteristic of the adopted biolayer deposition protocol, namely: the layer-by-layer (LbL) approach and the spin coating technique. The present study relies on a combined surface spectroscopic and morphological characterization. Specifically, X-ray photoelectron spectroscopy operated in the parallel angle-resolved mode allowed the non-destructive investigation of the in-depth chemical composition of the SA film, alone or in the presence of the P3HT overlayer. Spectroscopic data were supported and corroborated by the results obtained with a Scanning Electron and a Helium Ion microscope investigation performed on the SA layer that provided relevant information on the protein structural arrangement or on its surface morphology. Clear differences emerged between the SA layers prepared by the two approaches, with the layer-by-layer deposition resulting in a smoother and better defined bio-electronic interface. Such findings support the superior analytical performance shown by bioelectronic devices based on LbL-deposited protein layers over spin coated ones.

Biologically active Schiff bases containing thiophene/furan ring and their copper(II) complexes: Synthesis, spectral, nonlinear optical and density functional studies

NASA Astrophysics Data System (ADS)

Gündüzalp, Ayla Balaban; Özsen, İffet; Alyar, Hamit; Alyar, Saliha; Özbek, Neslihan

2016-09-01

Schiff bases; 1,8-bis(thiophene-2-carboxaldimine)-p-menthane (L1) and 1,8-bis(furan-2-carboxaldimine)-p-menthane (L2) have been synthesized and characterized by elemental analysis, 1Hsbnd 13C NMR, UV-vis, FT-IR and LC-MS methods. 1H and 13C shielding tensors for L1 and L2 were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments, nonlinear optical (NLO) activities, frontier molecular orbitals (FMOs) and absorption spectrum have been investigated by the same basis set. Schiff base-copper(II) complexes have been synthesized and structurally characterized with spectroscopic methods, magnetic and conductivity measurements. The spectroscopic data suggest that Schiff base ligands coordinate through azomethine-N and thiophene-S/furan-O donors (as SNNS and ONNO chelating systems) to give a tetragonal geometry around the copper(II) ions. Schiff bases and Cu(II) complexes have been screened for their biological activities on different species of pathogenic bacteria, those are, Gram positive bacteria: Bacillus subtitilus, Yersinia enterotica, Bacillus cereus, Listeria monocytogenes, Micrococcus luteus and Gram negative bacteria: Escherichia coli, Pseudomonas aeroginosa, Shigella dysenteriae, Salmonella typhi, Klebsiella pseudomonas by using microdilution technique (MIC values in mM). Biological activity results show that Cu(II) complexes have higher activities than parent ligands and metal chelation may affect significantly the antibacterial behavior of the organic ligands.

A Pragmatic Smoothing Method for Improving the Quality of the Results in Atomic Spectroscopy

NASA Astrophysics Data System (ADS)

Bennun, Leonardo

2017-07-01

A new smoothing method for the improvement on the identification and quantification of spectral functions based on the previous knowledge of the signals that are expected to be quantified, is presented. These signals are used as weighted coefficients in the smoothing algorithm. This smoothing method was conceived to be applied in atomic and nuclear spectroscopies preferably to these techniques where net counts are proportional to acquisition time, such as particle induced X-ray emission (PIXE) and other X-ray fluorescence spectroscopic methods, etc. This algorithm, when properly applied, does not distort the form nor the intensity of the signal, so it is well suited for all kind of spectroscopic techniques. This method is extremely effective at reducing high-frequency noise in the signal much more efficient than a single rectangular smooth of the same width. As all of smoothing techniques, the proposed method improves the precision of the results, but in this case we found also a systematic improvement on the accuracy of the results. We still have to evaluate the improvement on the quality of the results when this method is applied over real experimental results. We expect better characterization of the net area quantification of the peaks, and smaller Detection and Quantification Limits. We have applied this method to signals that obey Poisson statistics, but with the same ideas and criteria, it could be applied to time series. In a general case, when this algorithm is applied over experimental results, also it would be required that the sought characteristic functions, required for this weighted smoothing method, should be obtained from a system with strong stability. If the sought signals are not perfectly clean, this method should be carefully applied

Characterization of cytochrome c as marker for retinal cell degeneration by uv/vis spectroscopic imaging

NASA Astrophysics Data System (ADS)

Hollmach, Julia; Schweizer, Julia; Steiner, Gerald; Knels, Lilla; Funk, Richard H. W.; Thalheim, Silko; Koch, Edmund

2011-07-01

Retinal diseases like age-related macular degeneration have become an important cause of visual loss depending on increasing life expectancy and lifestyle habits. Due to the fact that no satisfying treatment exists, early diagnosis and prevention are the only possibilities to stop the degeneration. The protein cytochrome c (cyt c) is a suitable marker for degeneration processes and apoptosis because it is a part of the respiratory chain and involved in the apoptotic pathway. The determination of the local distribution and oxidative state of cyt c in living cells allows the characterization of cell degeneration processes. Since cyt c exhibits characteristic absorption bands between 400 and 650 nm wavelength, uv/vis in situ spectroscopic imaging was used for its characterization in retinal ganglion cells. The large amount of data, consisting of spatial and spectral information, was processed by multivariate data analysis. The challenge consists in the identification of the molecular information of cyt c. Baseline correction, principle component analysis (PCA) and cluster analysis (CA) were performed in order to identify cyt c within the spectral dataset. The combination of PCA and CA reveals cyt c and its oxidative state. The results demonstrate that uv/vis spectroscopic imaging in conjunction with sophisticated multivariate methods is a suitable tool to characterize cyt c under in situ conditions.

Raman Spectroscopic Detection of Graphitic Carbon of Biogenic Parentage in an Ancient South African Chert

NASA Technical Reports Server (NTRS)

Wang, Alian; Haskin, Larry A.; Kuebler, Karla E.; Jolliff, Bradley L.; Walsh, Maud M.

2001-01-01

The detection of reduced carbon in martian rocks and soils is important in the search for evidence of life. A Raman spectroscopic study of South Africa chert reveals that 50 ppm carbon or less can be determined by this technique. Additional information is contained in the original extended abstract.

Synthesis, and spectroscopic studies of charge transfer complex of 1,2-dimethylimidazole as an electron donor with π-acceptor 2,4-dinitro-1-naphthol in different polar solvents

NASA Astrophysics Data System (ADS)

Miyan, Lal; Khan, Ishaat M.; Ahmad, Afaq

2015-07-01

The charge transfer (CT) complex of 1,2-dimethylimidazole (DMI) as an electron donor with π acceptor 2,4-dinitro-1-naphthol (DNN) has been studied spectrophotometrically in different solvents like chloroform, acetonitrile, methanol, methylene chloride, etc. at room temperature. The CT complex which is formed through the transfer of lone pair electrons from DMI to DNN exhibits well resolved CT bands and the regions of these bands were remarkably different from those of the donor and acceptor. The stoichiometry of the CT complex was found to be 1:1 by a straight-line method between donor and acceptor with maximum absorption bands. The novel CT complex has been characterized by FTIR, TGA-DTA, powder XRD, 1H NMR and 13C NMR spectroscopic techniques. The Benesi-Hildebrand equation has been used to determine the formation constant (KCT), molar extinction coefficient (εCT), standard gibbs free energy (ΔG°) and other physical parameters of the CT complex. The formation constant recorded higher values and molar extinction coefficient recorded lower values in chloroform compared with methylene chloride, methanol and acetonitrile, confirming the strong interaction between the molecular orbital's of donor and acceptor in the ground state in less polar solvent. This CT complex has been studied by absorption spectra of donor 1,2-dimethylimidazole (DMI) and acceptor 2,4-dinitro-1-naphthol (DNN) by using the spectrophotometric technique in various solvents at room temperature.

Spectrometry: Report of panel

NASA Technical Reports Server (NTRS)

Farmer, C. Barney; Murcray, David G.; Abreu, Vincent; Gille, John C.; Hanel, Rudolph A.; Hoell, James M., Jr.; Jamieson, John A.; Zwick, Harold

1987-01-01

Spectroscopic measurements are required to define the spectral background and provide the detailed spectral information that is essential for the design of species-specific systems and the analysis of data obtained from them. This function of spectroscopic measurements is expected to be an important part of any tropospheric remote-sensing program, and both emission and absorption spectroscopy are relevant in this context. The data from such observations are of value to tropospheric science in their own right, during the initial phases while species-specific techniques and instruments are under development. In addition, there are a number of unresolved problems in tropospheric radiative transfer and spectroscopy which presently limit the accuracy and reliability of all remote sensing methods. Only through a supporting program of spectroscopic measurements can progress be made in improving the understanding of these aspects of radiative transfer and ultimately reaching the desired confidence in the accuracy to species-specific monitoring techniques.

Spectroscopic analysis of solar and cosmic X-ray spectra. 1: The nature of cosmic X-ray spectra and proposed analytical techniques

NASA Technical Reports Server (NTRS)

Walker, A. B. C., Jr.

1975-01-01

Techniques for the study of the solar corona are reviewed as an introduction to a discussion of modifications required for the study of cosmic sources. Spectroscopic analysis of individual sources and the interstellar medium is considered. The latter was studied via analysis of its effect on the spectra of selected individual sources. The effects of various characteristics of the ISM, including the presence of grains, molecules, and ionization, are first discussed, and the development of ISM models is described. The expected spectral structure of individual cosmic sources is then reviewed with emphasis on supernovae remnants and binary X-ray sources. The observational and analytical requirements imposed by the characteristics of these sources are identified, and prospects for the analysis of abundances and the study of physical parameters within them are assessed. Prospects for the spectroscopic study of other classes of X-ray sources are also discussed.

The Sloan Digital Sky Survey-II: Photometry and Supernova Ia Light Curves from the 2005 Data

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

Holtzman, Jon A.; /New Mexico State U.; Marriner, John

2010-08-26

We present ugriz light curves for 146 spectroscopically confirmed or spectroscopically probable Type Ia supernovae from the 2005 season of the SDSS-II Supernova survey. The light curves have been constructed using a photometric technique that we call scene modeling, which is described in detail here; the major feature is that supernova brightnesses are extracted from a stack of images without spatial resampling or convolution of the image data. This procedure produces accurate photometry along with accurate estimates of the statistical uncertainty, and can be used to derive photometry taken with multiple telescopes. We discuss various tests of this technique thatmore » demonstrate its capabilities. We also describe the methodology used for the calibration of the photometry, and present calibrated magnitudes and fluxes for all of the spectroscopic SNe Ia from the 2005 season.« less

Glucose Oxidase Adsorption on Sequential Adsorbed Polyelectrolyte Films Studied by Spectroscopic Techniques

NASA Astrophysics Data System (ADS)

Tristán, Ferdinando; Solís, Araceli; Palestino, Gabriela; Gergely, Csilla; Cuisinier, Frédéric; Pérez, Elías

2005-04-01

The adsorption of Glucose Oxidase (GOX) on layers of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) deposited on Sequentially Adsorbed Polyelectrolyte Films (SAPFs) were studied by three different spectroscopic techniques. These techniques are: Optical Wave Light Spectroscopy (OWLS) to measure surface density; Fluorescence Resonance Energy Transfer (FRET) to verify the adsorption of GOX on the surface; and Fourier Transform Infrared Spectroscopy in Attenuated Total Reflection mode (FTIR-HATR) to inspect local structure of polyelectrolytes and GOX. Two positive and two negative polyelectrolytes are used: Cationic poly(ethyleneimine) (PEI) and poly(allylamine hydrochloride) (PAH) and anionic poly(sodium 4-styrene sulfonate) (PSS) and poly(acrylic acid) (PAA). These spectroscopic techniques do not require any labeling for GOX or SAPFs, specifically GOX and PSS are naturally fluorescent and are used as a couple donor-acceptor for the FRET technique. The SAPFs are formed by a (PEI)-(PSS/PAH)2 film followed by (PAA/PAH)n bilayers. GOX is finally deposited on top of SAPFs at different values of n (n=1..5). Our results show that GOX is adsorbed on positive ended SAPFs forming a monolayer. Contrary, GOX adsorption is not observed on negative ended film polyelectrolyte. GOX stability was tested adding a positive and a negative polyelectrolyte after GOX adsorption. Protein is partially removed by PAH and PAA, with lesser force by PAA.

A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

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

Shen, Yujie, E-mail: styojm@physics.tamu.edu; Voronine, Dmitri V.; Sokolov, Alexei V.

2015-08-15

We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

High-Throughput Characterization of Vapor-Deposited Organic Glasses

NASA Astrophysics Data System (ADS)

Dalal, Shakeel S.

Glasses are non-equilibrium materials which on short timescales behave like solids, and on long timescales betray their liquid-like structure. The most common way of preparing a glass is to cool the liquid faster than it can structurally rearrange. Until recently, most preparation schemes for a glass were considered to result in materials with undifferentiable structure and properties. This thesis utilizes a particular preparation method, physical vapor deposition, in order to prepare glasses of organic molecules with properties otherwise considered to be unobtainable. The glasses are characterized using spectroscopic ellipsometry, both as a dilatometric technique and as a reporter of molecular packing. The results reported here develop ellipsometry as a dilatometric technique on a pair of model glass formers, alpha,alpha,beta-trisnaphthylbenzene and indomethacin. It is found that the molecular orientation, as measured by birefringence, can be tuned by changing the substrate temperature during the deposition. In order to efficiently characterize the properties of vapor-deposited indomethacin as a function of substrate temperature, a high-throughput method is developed to capture the entire interesting range of substrate temperatures in just a few experiments. This high-throughput method is then leveraged to describe molecular mobility in vapor-deposited indomethacin. It is also used to demonstrate that the behavior of organic semiconducting molecules agrees with indomethacin quantitatively, and this agreement has implications for emerging technologies such as light-emitting diodes, photovoltaics and thin-film transistors made from organic molecules.

A Parallel Spectroscopic Method for Examining Dynamic Phenomena on the Millisecond Time Scale

PubMed Central

Snively, Christopher M.; Chase, D. Bruce; Rabolt, John F.

2009-01-01

An infrared spectroscopic technique based on planar array infrared (PAIR) spectroscopy has been developed that allows the acquisition of spectra from multiple samples simultaneously. Using this technique, it is possible to acquire spectra over a spectral range of 950–1900cm−1 with a temporal resolution of 2.2ms. The performance of this system was demonstrated by determining the shear-induced orientational response of several low molecular weight liquid crystals. Five different liquid crystals were examined in combination with five different alignment layers, and both primary and secondary screens were demonstrated. Implementation of this high throughput PAIR technique resulted in a reduction in acquisition time as compared to both step-scan and ultra-rapid-scanning FTIR spectroscopy. PMID:19239197

New transition metal complexes and their ring-opened polymers

NASA Astrophysics Data System (ADS)

Apodaca, Paula

An exciting new class of metallacycle (eta5-C5 H4Fe) (CO)2CH2SiR2 that undergoes ring-opening polymerization was recently reported by Sharma et al. [1]. We are interested in further expanding this research area by synthesizing related cyclopentadienyl derivatives containing Fe, Mo, and W in combination with other elements of the group 14. We report here the synthesis and crystal structure characterization of new germa-metallacyclobutanes of Mo and W. In addition, we have successfully synthesized and characterized new ring-opening polymers of the related germanium systems [(eta5-C5 H4Fe)(CO) 2(CH2GeR2)] n. The new polymers were characterized using various spectroscopic techniques and gel permeation chromatography. The recent report on the synthesis of a new class of siloxane polymers based upon base-catalyzed ring opening of phenylene-bridged cyclic siloxanes [2] encouraged us to investigate the related ferrocenyl (Fc, (C5H 5)Fe(C5H4)) siloxane systems. The incorporation of ferrocene could provide new materials with all the interesting properties usually associated with these groups such as thermal and photochemical stability, electrochemical activity and potentially conducting materials. Thus far a new required organometallic monomer containing Fc-R, where R = disilaoxacyclopentene 5 has been synthesized and completely characterized. Based-induced ring-opening polymerizations of 5 were attempted under different reaction conditions and produced, inter alia: (C5H5)Fe(C 5H4)C(SiMe2OH)=CH(SiMe2R), R = nBu (2), tBu (3), Ph (4). The single crystal X-ray structures and full spectroscopic analysis of such products has been accomplished. Furthermore, the reactivity of the ferrocenyl silanols concerning condensation and their behavior under acidic conditions has been investigated. 1Sharma, H.; Cervantes-Lee, F.; Pannell, K. H. J. Am. Chem. Soc. 2004, 126, 1326. 2 Loy, A. D.; Rahimian, K.; Samara, M. Angew. Chem. 1999, 38, 45.

Spectroscopic Characterization of Streptavidin Functionalized Quantum dots1

PubMed Central

Wu, Yang; Lopez, Gabriel P.; Sklar, Larry A.; Buranda, Tione

2007-01-01

The spectroscopic properties of quantum dots can be strongly influenced by the conditions of their synthesis. In this work we have characterized several spectroscopic properties of commercial, streptavidin functionalized quantum dots (QD525, lot#1005-0045 and QD585, Lot#0905-0031 from Invitrogen). This is the first step in the development of calibration beads, to be used in a generalizable quantification scheme of multiple fluorescent tags in flow cytometry or microscopy applications. We used light absorption, photoexcitation, and emission spectra, together with excited-state lifetime measurements to characterize their spectroscopic behavior, concentrating on the 400-500nm wavelength ranges that are important in biological applications. Our data show an anomalous dependence of emission spectrum, lifetimes, and quantum yield (QY) on excitation wavelength that is particularly pronounced in the QD525. For QD525, QY values ranged from 0.2 at 480nm excitation up to 0.4 at 450nm and down again to 0.15 at 350nm. For QD585, QY values were constant at 0.2 between 500nm and 400nm, but dropped to 0.1 at 350nm. We attribute the wavelength dependences to heterogeneity in size and surface defects in the QD525, consistent with characteristics previously described in the chemistry literature. The results are discussed in the context of bridging the gap between what is currently known in the physical chemistry literature of quantum dots, and the quantitative needs of assay development in biological applications. PMID:17368555

Silver sulfadoxinate: Synthesis, structural and spectroscopic characterizations, and preliminary antibacterial assays in vitro

NASA Astrophysics Data System (ADS)

Zanvettor, Nina T.; Abbehausen, Camilla; Lustri, Wilton R.; Cuin, Alexandre; Masciocchi, Norberto; Corbi, Pedro P.

2015-02-01

The sulfa drug sulfadoxine (SFX) reacted with Ag+ ions in aqueous solution, affording a new silver(I) complex (AgSFX), which was fully characterized by chemical, spectroscopic and structural methods. Elemental, ESI-TOF mass spectrometric and thermal analyses of AgSFX suggested a [Ag(C12H13N4O2S)] empirical formula. Infrared spectroscopic measurements indicated ligand coordination to Ag(I) through the nitrogen atoms of the (deprotonated) sulfonamide group and by the pyrimidine ring, as well as through oxygen atom(s) of the sulfonamide group. These hypotheses were corroborated by 13C and 15N SS-NMR spectroscopy and by an unconventional structural characterization based on X-ray powder diffraction data. The latter showed that AgSFX crystallizes as centrosymmetric dimers with a strong Ag⋯Ag interaction of 2.7435(6) Å, induced by the presence of exo-bidentate N,N‧ bridging ligands and the formation of an eight-membered ring of [AgNCN]2 sequence, nearly planar. Participation of oxygen atoms of the sulfonamide residues generates in the crystal a 1D coordination polymer, likely responsible for its very limited solubility in all common solvents. Besides the analytical, spectroscopic and structural description, the antibacterial properties of AgSFX were assayed using disc diffusion methods against Escherichia coli and Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains. The AgSFX complex showed to be active against Gram-positive and Gram-negative bacterial strains, being comparable to the activities of silver sulfadiazine.

Chromocene in porous polystyrene: an example of organometallic chemistry in confined spaces.

PubMed

Estephane, Jane; Groppo, Elena; Vitillo, Jenny G; Damin, Alessandro; Lamberti, Carlo; Bordiga, Silvia; Zecchina, Adriano

2009-04-07

In this work, we present an innovative approach to investigate the structure and the reactivity of a molecularly dispersed organometallic compound. The poly(4-ethylstyrene-co-divinylbenzene) microporous system (PS) is used as "solid solvent" able to molecularly disperse CrCp2, allowing: (i) its full characterization by means of spectroscopic techniques; (ii) the pressure and temperature dependent study of its interaction towards simple molecules like CO freely diffusing through the pores; (iii) the accurate determination of the reaction enthalpies by both direct microcalorimetric measurements and by an indirect spectroscopic approach. The experimental results are compared with quantum-mechanical calculations adopting the DFT approximation with two different functionals (namely BP86 and B3-LYP), showing the limitations and the potentialities of DFT methods in predicting the properties of open shell systems. It is concluded that modern DFT methods are able to give a coherent view of the vibrational properties of the CrCp2 molecule (and of the complex formed upon CO adsorption) that well match the experimental results, while the energetic predictions should be taken with care as they are significantly dependent on the functionals used.

Report on cascade energy relaxation from PVP to Tb3+:Bi2SiO5 nanophosphor through salicylic acid in composite polymeric film

NASA Astrophysics Data System (ADS)

Kumari, Pushpa; Dwivedi, Y.

2018-05-01

The present article reports structural and spectroscopic properties of Tb:Bi2SiO5 nanophosphors dispersed in Polyvinylpyrrolidone polymer film, in presence of Salicylic acid (SA) molecule, which acts as a sensitizer. Detailed structural and spectroscopic characterizations were carried out using X-ray diffraction patterns, Scanning Electron Microscope, Fourier Transform Infrared and Excitation and photoluminescence techniques. The mean crystallite size of Tb3+:Bi2SiO5 nanophosphor and Tb3+:Bi2SiO5 in Polyvinylpyrrolidone polymer composite was estimated ∼22 nm and ∼28 nm, respectively. We have report atleast two times enhancement in Tb3+ ions emission intensity due to the efficient energy transfer from salicylic acid molecule to Tb ions. In addition to energy transfer from salicylic acid, the Polyvinylpyrrolidone polymeric host was also reported to serve as a sensitizer for SA molecule and Tb3+ ions through a cascade energy relaxation process while exciting with 248 nm photons. On 248 nm photon excitation, atleast five improvements in Tb3+ ion emission intensity are reported. Presence of SA molecule facilitates precise colour tuning as obvious from the CIE coordinates.

Molecular structure and spectroscopic characterization of Carbamazepine with experimental techniques and DFT quantum chemical calculations.

PubMed

Suhasini, M; Sailatha, E; Gunasekaran, S; Ramkumaar, G R

2015-04-15

A systematic vibrational spectroscopic assignment and analysis of Carbamazepine has been carried out by using FT-IR, FT-Raman and UV spectral data. The vibrational analysis were aided by electronic structure calculations - ab initio (RHF) and hybrid density functional methods (B3LYP) performed with standard basis set 6-31G(d,p). Molecular equilibrium geometries, electronic energies, natural bond order analysis, harmonic vibrational frequencies and IR intensities have been computed. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED) by VEDA program. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λmax were determined by HF/6-311++G(d,p) Time-Dependent method. The thermodynamic functions of the title molecule were also performed using the RHF and DFT methods. The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance (NMR) calculation procedure was also performed, and it was used for assigning the (13)C and (1)H NMR chemical shifts of Carbamazepine. Copyright © 2015 Elsevier B.V. All rights reserved.

Dynamic and spectroscopic studies of nano-micelles comprising dye in water/ dioctyl sodium sulfosuccinate /decane droplet microemulsion at constant water content

NASA Astrophysics Data System (ADS)

Rahdar, Abbas; Almasi-Kashi, Mohammad

2017-01-01

In the present work, the dynamic and spectroscopic properties of water-in-decane dioctyl sodium sulfosuccinate (AOT) microemulsions comprising dye, Rhodamine B (RB), were studied by varying content of decane at the constant water content (W = 20), by using dynamic light scattering (DLS), UV/visible, and fluorescence techniques. The characterization results of DLS of AOT micelles showed that by decreasing concentration of Rhodamine B in the water/AOT/decane microemulsion, the inter-droplet interactions changed from attractive to repulsive as the mass fraction of nano-droplets (MFD) increased. A deviation in the absorption spectra of Rhodamine B from the Beer's law at the high Rhodamine B concentration (0.001) was observed in the AOT reversed micelles. The Quenching in the emission intensity of AOT droplets comprising Rhodamine B and red shift in λmax of fluorescence of dye was observed as a function of concentration of RB in AOT RMs. The Stokes shift of AOT droplets containing the high concentration of RB, increased with mass fraction of nano-droplet (MFD), whereas at the low Rhodamine B concentration, its variation remained constant up to MFD = 0.07, and then increased.

Nuclear blebbing of biologically active organoselenium compound towards human cervical cancer cell (HeLa): in vitro DNA/HSA binding, cleavage and cell imaging studies.

PubMed

Rizvi, Masood Ahmad; Zaki, Mehvash; Afzal, Mohd; Mane, Manoj; Kumar, Manjeet; Shah, Bhahwal Ali; Srivastav, Saurabh; Srikrishna, Saripella; Peerzada, Ghulam Mustafa; Tabassum, Sartaj

2015-01-27

New pharmacophore organoselenium compound (1) was designed, synthesized and characterized by various spectroscopic methods (IR, ESI-MS, (1)H, (13)C and (77)Se NMR) and further confirmed by X-ray crystallography. Compound 1 consists of two 3,5-bis(trifluoromethyl)phenyl units which are connected to the selenium atom via the organometallic C-Se bond. In vitro DNA binding studies of 1 was investigated by absorption and emission titration methods which revealed that 1 recognizes the minor groove of DNA in accordance with molecular docking studies with the DNA duplex. Gel electrophoretic assay demonstrates the ability of 1 to cleave pBR322 DNA through hydrolytic process which was further validated by T4 religation assay. To understand the drug-protein interaction of which ultimate molecular target was DNA, the affinity of 1 towards HSA was also investigated by the spectroscopic and molecular modeling techniques which showed hydrophobic interaction in the subdomain IIA of HSA. Furthermore, the intracellular localization of 1 was evidenced by cell imaging studies using HeLa cells. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Molecular Organization Induced Anisotropic Properties of Perylene - Silica Hybrid Nanoparticles.

PubMed

Sriramulu, Deepa; Turaga, Shuvan Prashant; Bettiol, Andrew Anthony; Valiyaveettil, Suresh

2017-08-10

Optically active silica nanoparticles are interesting owing to high stability and easy accessibility. Unlike previous reports on dye loaded silica particles, here we address an important question on how optical properties are dependent on the aggregation-induced segregation of perylene molecules inside and outside the silica nanoparticles. Three differentially functionalized fluorescent perylene - silica hybrid nanoparticles are prepared from appropriate ratios of perylene derivatives and tetraethyl orthosilicate (TEOS) and investigated the structure property correlation (P-ST, P-NP and P-SF). The particles differ from each other on the distribution, organization and intermolecular interaction of perylene inside or outside the silica matrix. Structure and morphology of all hybrid nanoparticles were characterized using a range of techniques such as electron microscope, optical spectroscopic measurements and thermal analysis. The organizations of perylene in three different silica nanoparticles were explored using steady-state fluorescence, fluorescence anisotropy, lifetime measurements and solid state polarized spectroscopic studies. The interactions and changes in optical properties of the silica nanoparticles in presence of different amines were tested and quantified both in solution and in vapor phase using fluorescence quenching studies. The synthesized materials can be regenerated after washing with water and reused for sensing of amines.

A Developmental History of Polymer Mass Spectrometry

ERIC Educational Resources Information Center

Vergne, Matthew J.; Hercules, David M.; Lattimer, Robert P.

2007-01-01

The history of the development of mass spectroscopic methods used to characterize polymers is discussed. The continued improvements in methods and instrumentation will offer new and better ways for the mass spectral characterization of polymers and mass spectroscopy (MS) should be recognized as a complementary polymer characterization method along…

Preparation, characterization and crystal structures of three salts of the quaterpyridine ligand

NASA Astrophysics Data System (ADS)

Ciesielski, Artur; Stefankiewicz, Artur R.; Patroniak, Violetta; Kubicki, Maciej

2009-07-01

As a result of a reaction between 6,6'''-dimethyl-2,2':6',2'':6'',2'''-quaterpyridine C 22H 18N 4 and lanthanide(III) salts, compounds, [C 22H 20N 4] 2+·2(CF 3SO 3) - ( 1) and [C 22H 20N 4] 2+·2(ClO 4) - ( 2), have been obtained. They were characterized by spectroscopic techniques (ESI-MS, NMR, IR), elemental analysis, and their formulae were confirmed on the basis of X-ray crystallography. It turned out that the perchlorate crystallizes as two solvates: with acetonitrile and disordered water molecules. These are the first structural characterization of a 6,6'″-dimethyl-2,2':6',2″:6″,2'″-quaterpyridinium dication. Due to the intramolecular hydrogen bond it adopts the previously unobserved cis/trans/cis conformation. In all three crystals the dications have C i symmetry, they occupy the special positions in their respective space groups. In the crystal structures the π-π stacking and weak hydrogen bonds add directionality to the dominating electrostatic interactions between cations and anions.

Artemisinin nanoformulation suitable for intravenous injection: Preparation, characterization and antimalarial activities.

PubMed

Ibrahim, Nehal; Ibrahim, Hany; Sabater, Alicia Moreno; Mazier, Dominique; Valentin, Alexis; Nepveu, Françoise

2015-11-30

More than 40 years after its discovery, artemisinin has become the most promising antimalarial agent. However, no intravenous formulation is available due to its poor aqueous solubility. Here, we report the preparation, characterization, and in vitro and in vivo biological evaluation of biodegradable albumin-bound artemisinin nanoparticles. The nanoparticles were prepared by a combination of a bottom-up and a top-down processes and characterized by different spectroscopic techniques. The preparation process was optimized to develop a nanoformulation with the smallest possible diameter and good homogeneity suitable for intravenous injection enabling direct contact of artemisinin with infected erythrocytes. Chemically and physically stable artemisinin nanoparticles were obtained with excellent entrapment efficiency. In in vitro experiments, the artemisinin nanoformulation was interestingly more effective than non-formulated artemisinin. In Plasmodiumm falciparum-infected 'humanized' mice, the nanoparticles proved to be highly effective with 96% parasitemia inhibition at 10mg/kg/day, prolonging mean survival time without recrudescence. This nanoparticulate albumin-bound system allows the intravenous administration of artemisinin for the first time without harsh organic solvents or cosolvents with 100% bioavailability. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of Fiber Optic ATR-FTIR Methods for In Situ Characterization of Protein Delivery Systems in Real Time

PubMed Central

McFearin, Cathryn L.; Sankaranarayanan, Jagadis; Almutairi, Adah

2011-01-01

Real Time Characterization of Protein Delivery Systems A fiber optic coupled ATR-FTIR spectroscopy technique was applied to the study of two different therapeutic delivery systems, acid degradable hydrogels and nanoparticles. Real time exponential release of a model protein, human serum albumin (HSA), was observed from two different polymeric hydrogels formulated with a pH sensitive crosslinker. Spectroscopic examination of nanoparticles formulated with an acid degradable polymer shell and encapsulated HSA exhibited vibrational signatures characteristic of both particle and payload when exposed to lowered pH conditions demonstrating the ability of this methodology to simultaneously measure phenomena arising from a system with a mixture of components. In addition, thorough characterization of these pH sensitive delivery vehicles without encapsulated protein was also accomplished in order to separate the effects of the payload during degradation. By providing in situ, real time detection in combination with the ability to specifically identify different components in a mixture without involved sample preparation and minimal sample disturbance, the versatility and suitability of this type of experiment for research in the pharmaceutical field is demonstrated. PMID:21476582

Push-through Direction Injectin NMR Automation

EPA Science Inventory

Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are the two major spectroscopic techniques successfully used in metabolomics studies. The non-invasive, quantitative and reproducible characteristics make NMR spectroscopy an excellent technique for detection of endogeno...

Chemistry of MOS-LSI radiation hardening

NASA Technical Reports Server (NTRS)

Grunthaner, P.

1985-01-01

The objective of this task was to obtain chemical information on MOS test samples. Toward this end, high resolution X-ray photoemission spectroscopy (XPS) has been the primary techniques used to characterize the chemistry and structure of the SiO2/Si interface for a variety of MOS structures with differing degrees of susceptibility to damage by ionizing radiation. The major accomplishments of this program are: (1) the identification of a structurally distinct region of SiO2 in the near-interfacial region of thermal SiO2 on Si; (2) the identification in the near-interfacial region of SiO2 structural differences between radiation hard and soft gate oxides; (3) the direct observation of radiation-induced damage sites in thermal SiO2 with XPS using in situ electron stress; (4) the correlation of suboxide state distributions at the SiO2/Si interface with processing parameters and radiation susceptibility; (5) the development of a chemical mechanism for radiation-induced interface state generation in SiO2/Si structures; and (6) the development benign chemical profiling techniques which permit the investigation of oxide/semiconductor structures using surface sensitive electron spectroscopic techniques.

On the magnetic polarizability tensor of US coinage

NASA Astrophysics Data System (ADS)

Davidson, John L.; Abdel-Rehim, Omar A.; Hu, Peipei; Marsh, Liam A.; O'Toole, Michael D.; Peyton, Anthony J.

2018-03-01

The magnetic dipole polarizability tensor of a metallic object gives unique information about the size, shape and electromagnetic properties of the object. In this paper, we present a novel method of coin characterization based on the spectroscopic response of the absolute tensor. The experimental measurements are validated using a combination of tests with a small set of bespoke coin surrogates and simulated data. The method is applied to an uncirculated set of US coins. Measured and simulated spectroscopic tensor responses of the coins show significant differences between different coin denominations. The presented results are encouraging as they strongly demonstrate the ability to characterize coins using an absolute tensor approach.

Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins

NASA Astrophysics Data System (ADS)

Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

2016-03-01

The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm- 1 and 1545 cm- 1, respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

Innovative combination of spectroscopic techniques to reveal nanoparticle fate in a crop plant

NASA Astrophysics Data System (ADS)

Larue, Camille; Castillo-Michel, Hiram; Stein, Ricardo J.; Fayard, Barbara; Pouyet, Emeline; Villanova, Julie; Magnin, Valérie; Pradas del Real, Ana-Elena; Trcera, Nicolas; Legros, Samuel; Sorieul, Stéphanie; Sarret, Géraldine

2016-05-01

Nanotechnology is the new industrial revolution of our century. Its development leads to an increasing use of nanoparticles and thus to their dissemination. Their fate in the environment is of great concern and especially their possible transfer in trophic chains might be an issue for food safety. However, so far our knowledge on this topic has been restricted by the lack of appropriate techniques to characterize their behavior in complex matrices. Here, we present in detail the use of cutting-edge beam-based techniques for nanoparticle in situ localization, quantification and speciation in a crop plant species (Lactuca sativa). Lettuce seedlings have been exposed to TiO2 and Ag nanoparticles and analyzed by inductively coupled plasma spectrometry, micro-particle induced X-ray emission coupled to Rutherford backscattering spectroscopy on nuclear microprobe, micro-X-ray fluorescence spectroscopy and X-ray absorption near edge structure spectroscopy. The benefits and drawbacks of each technique are discussed, and the types of information that can be drawn, for example on the translocation to edible parts, change of speciation within the plant, detoxification mechanisms, or impact on the plant ionome, are highlighted. Such type of coupled approach would be an asset for nanoparticle risk assessment.

L-shaped benzimidazole fluorophores: synthesis, characterization and optical response to bases, acids and anions.

PubMed

Lirag, Rio Carlo; Le, Ha T M; Miljanić, Ognjen Š

2013-05-14

Nine L-shaped benzimidazole fluorophores have been synthesized, computationally evaluated and spectroscopically characterized. These "half-cruciform" fluorophores respond to bases, acids and anions through changes in fluorescence that vary from moderate to dramatic.

HPCO—A Phosphorus‐Containing Analogue of Isocyanic Acid

PubMed Central

Hinz, Alexander; Labbow, René; Rennick, Chris; Schulz, Axel

2017-01-01

Abstract We describe the isolation and spectroscopic characterization of the heavier phosphorus‐containing analogue of isocyanic acid (HPCO), and its isotopologue (DPCO). This fundamental small molecule, which has been postulated to exist in interstellar space, has thus far only been observed at low gas phase concentrations or in inert gas matrices. In this report we describe its synthesis, spectroscopic properties, and reactivity in solution. PMID:28252258

Electroanalytical Evaluation of Nanoparticles by Nano-impact Electrochemistry

NASA Astrophysics Data System (ADS)

Karimi, Anahita

Applications of engineered nanoparticles in electronics, catalysis, solid oxide fuel cells, medicine and sensing continue to increase. Traditionally, nanoparticle systems are characterized by spectroscopic and microscopic techniques. These methods are cumbersome and expensive, which limit their routine use for screening purposes. Electrochemistry is a powerful, yet underutilized tool, for the detection and classification of nanoparticles. The first part of this dissertation investigates a recently developed electrochemical method -- nanoparticle collision electrochemistry -- for detection and characterization of nanoparticles. Three independent projects have been described to evaluate the use of this technique for characterizing nanoparticle based systems including: conjugation with biomolecules, interaction with environmental contaminants and fundamental investigation of conformational changes of nanoparticle capping ligands. The thesis reports the first use of nano-impact electrochemistry to quantitatively investigate bioconjugation and biomolecular recognition at conductive nanoparticles. Furthermore, we also demonstrate the potential of this method as a single step, reagentless and label-free technique for the ultra-sensitive detection of biomolecular targets. A fundamental study of biorecognition is important for the development of therapeutics and molecular diagnosis probes in the biomedical, biosensing and biotechnology fields. The second project describes the use of this method as a screening tool of particle reactivity. We study the interaction and adsorption of a toxic environmental metalloid (Arsenic) with metal oxide nanoparticles to extract mechanistic, speciation and loading information. We discuss the potential of this approach to complement or replace costly characterization techniques and enable routine study of nanoparticles and their reactivity. In the third project, we use the nano-impact method to study the pH-dependent conformational changes of polymeric capping agents on the surface of silver nanoparticles. Nano-impact elecrochemistry has demonstrated promising results for studying functionality, stability and conformational changes of stabilizing agents. The second part of this thesis explores the use of carbon nanomaterials such as graphene and Pt-doped CeO2 for the rational design of enzyme-conjugated nanostructures for biosensing applications. The dissertation reports fabrication, characterization and properties of hybrid CeO2-based bioelectrocatalytic nanostructure material with PEDOT:PSS [poly(3,4ethylenedioxythiophene):poly-styrene-sulfonic acid] on porous carbon materials as novel materials for designing high performance laccase (Lac) biocathodes and biofuel cells.

Oleic Acid Produced by a Marine Vibrio spp. Acts as an Anti-Vibrio parahaemolyticus Agent

PubMed Central

Leyton, Yanett; Borquez, Jorge; Darias, José; Cueto, Mercedes; Díaz-Marrero, Ana R.; Riquelme, Carlos

2011-01-01

It is known that some strains of Vibrio parahaemolyticus are responsible for gastroenteric diseases caused by the ingestion of marine organisms contaminated with these bacterial strains. Organic products that show inhibitory activity on the growth of the pathogenic V. parahaemolyticus were extracted from a Vibrio native in the north of Chile. The inhibitory organic products were isolated by reverse phase chromatography and permeation by Sephadex LH20, and were characterized by spectroscopic and spectrometric techniques. The results showed that the prevailing active product is oleic acid, which was compared with standards by gas chromatography and high-performance liquid chromatography (HPLC). These active products might be useful for controlling the proliferation of pathogenic clones of V. parahaemolyticus. PMID:22073014

Optical Imaging and Spectroscopic Characterization of Self-Assembled Environmental Adsorbates on Graphene

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

Gallagher, Patrick; Li, Yilei; Watanabe, Kenji

Topographic studies using scanning probes have found that graphene surfaces are often covered by micron-scale domains of periodic stripes with a 4 nm pitch. These stripes have been variously interpreted as structural ripples or as self-assembled adsorbates. We show that the stripe domains are optically anisotropic by imaging them using a polarization-contrast technique. Optical spectra between 1.1 and 2.8 eV reveal that the anisotropy in the in-plane dielectric function is predominantly real, reaching 0.6 for an assumed layer thickness of 0.3 nm. Furthermore, the spectra are incompatible with a rippled graphene sheet but would be quantitatively explained by the self-assemblymore » of chainlike organic molecules into nanoscale stripes.« less

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide.

PubMed

Madasu, Suri Babu; Vekariya, Nagaji Ambabhai; Kiran, M N V D Hari; Gupta, Badarinadh; Islam, Aminul; Douglas, Paul S; Babu, Korupolu Raghu

2012-01-01

Eletriptan hydrobromide (1) is a selective serotonin (5-HT(1)) agonist, used for the acute treatment of the headache phase of migraine attacks. During the manufacture of eletriptan hydrobromide the formation of various impurities were observed and identified by LC-MS. To control the formation of these impurities during the preparation of active pharmaceutical ingredients, the structure of the impurities must be known. Major impurities of the eletriptan hydrobromide synthesis were prepared and characterized by using various spectroscopic techniques, i.e., mass spectroscopy, FTIR , (1)H NMR, (13)C NMR/DEPT, and further confirmed by co-injection in HPLC. The present study will be of great help in the synthesis of highly pure eletriptan hydrobromide related compounds.

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide

PubMed Central

Madasu, Suri Babu; Kiran, M N V D Hari; Gupta, Badarinadh; Islam, Aminul; Douglas, Paul S; Babu, Korupolu Raghu

2012-01-01

Summary Eletriptan hydrobromide (1) is a selective serotonin (5-HT1) agonist, used for the acute treatment of the headache phase of migraine attacks. During the manufacture of eletriptan hydrobromide the formation of various impurities were observed and identified by LC–MS. To control the formation of these impurities during the preparation of active pharmaceutical ingredients, the structure of the impurities must be known. Major impurities of the eletriptan hydrobromide synthesis were prepared and characterized by using various spectroscopic techniques, i.e., mass spectroscopy, FTIR , 1H NMR, 13C NMR/DEPT, and further confirmed by co-injection in HPLC. The present study will be of great help in the synthesis of highly pure eletriptan hydrobromide related compounds. PMID:23019477

Acridine-1, 8-diones - A new class of thermally stable NLOphores: Photophysical, (hyper)polarizability and TD-DFT studies

NASA Astrophysics Data System (ADS)

Thorat, Kishor G.; Tayade, Rajratna P.; Sekar, Nagaiyan

2016-12-01

Linear and non-linear optical properties of a series of new acridine-1, 8-dione derivatives are investigated in different solvents by using solvatochromic and computational methods. Values of first-order hyperpolarizabilities (βCT or β0) obtained using solvatochromic and computational methods are compared with the reported values for urea and 3-aminoxanthone. The new materials under study show first hyperpolarizability values 2.3 to 5.6 times larger than that of urea and 2 to 15.6 times more than that of 3-aminoxanthone. The dyes possess very high thermal stabilities. The dyes are prepared using one pot multicomponent reaction between dimedone, various aromatic aldehydes and amino acids, and characterized by spectroscopic techniques.

Efficient photocatalytic degradation of rhodamine 6G with a quantum dot-metal organic framework nanocomposite.

PubMed

Kaur, Rajnish; Vellingiri, Kowsalya; Kim, Ki-Hyun; Paul, A K; Deep, Akash

2016-07-01

The hybrid structures of metal organic frameworks (MOFs) and nanoparticles may offer the realization of effective photocatalytic materials due to combined benefits of the porous and molecular sieving properties of MOF matrix and the functional characteristics of encapsulated nanoparticles. In this study, cadmium telluride (CdTe) quantum dots (QD) are conjugated with a europium-MOF for the synthesis of a novel nanocomposite material with photocatalytic properties. Successful synthesis of a QD/Eu-MOF nanocomposite was characterized with various spectroscopic and microscopic techniques. This QD/Eu-MOF is found to be an effective catalyst to complete the degradation of Rhodamine 6G dye within 50 min. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maple prepared organic heterostructures for photovoltaic applications

NASA Astrophysics Data System (ADS)

Stanculescu, A.; Socol, M.; Socol, G.; Mihailescu, I. N.; Girtan, M.; Stanculescu, F.

2011-09-01

In this study, we present the deposition of ZnPc, Alq3, and PTCDA thin films using Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. We also report the realisation of multilayer structures, made by the successive application of MAPLE. The films have been characterized by spectroscopic (UV-VIS and Photoluminescence) and microscopic (SEM and AFM) methods, and the effect of different deposition conditions such as fluence, number of pulses, and target concentration on the properties has been analysed. This paper also presents some investigations on the electrical conduction in sandwich type structures ITO or Si/organic layer/Au or Cu and ITO/double organic layer/Cu, emphasising the dominant effect of the height of the energetic barriers at the inorganic/organic and organic/organic interfaces.

Characterization of the surface physico-chemistry of plasticized PVC used in blood bag and infusion tubing.

PubMed

Al Salloum, H; Saunier, J; Dazzi, A; Vigneron, J; Etcheberry, A; Marlière, C; Aymes-Chodur, C; Herry, J M; Bernard, M; Jubeli, E; Yagoubi, N

2017-06-01

Commercial infusion tubing and blood storage devices (tubing, blood and platelets bags) made of plasticized PVC were analyzed by spectroscopic, chromatographic and microscopic techniques in order to identify and quantify the additives added to the polymer (lubricants, thermal stabilizers, plasticizers) and to put into evidence their blooming onto the surface of the devices. For all the samples, deposits were observed on the surface but with different kinds of morphologies. Ethylene bis amide lubricant and metallic stearate stabilizers were implicated in the formation of these layers. In contact with aqueous media, these insoluble deposits were damaged, suggesting a possible particulate contamination of the infused solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

Thiadiazole derivatives as New Class of β-glucuronidase inhibitors.

PubMed

Salar, Uzma; Taha, Muhammad; Ismail, Nor Hadiani; Khan, Khalid Mohammed; Imran, Syahrul; Perveen, Shahnaz; Wadood, Abdul; Riaz, Muhammad

2016-04-15

Thiadiazole derivatives 1-24 were synthesized via a single step reaction and screened for in vitro β-glucuronidase inhibitory activity. All the synthetic compounds displayed good inhibitory activity in the range of IC50=2.16 ± 0.01-58.06 ± 1.60 μM as compare to standard d-saccharic acid 1,4-lactone (IC50=48.4 ± 1.25 μM). Molecular docking study was conducted in order to establish the structure-activity relationship (SAR) which demonstrated that thiadiazole as well as both aryl moieties (aryl and N-aryl) involved to exhibit the inhibitory potential. All the synthetic compounds were characterized by spectroscopic techniques (1)H, (13)C NMR, and EIMS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Utility of positron annihilation lifetime technique for the assessment of spectroscopic data of some charge-transfer complexes derived from N-(1-Naphthyl)ethylenediamine dihydrochloride

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; Adam, Abdel Majid A.; Sharshar, T.; Saad, Hosam A.; Eldaroti, Hala H.

2014-03-01

In this work, structural, thermal, morphological, pharmacological screening and positron annihilation lifetime measurements were performed on the interactions between a N-(1-Naphthyl)ethylenediamine dihydrochloride (NEDA·2HCl) donor and three types of acceptors to characterize these CT complexes. The three types of acceptors include π-acceptors (quinol and picric acid), σ-acceptors (iodine) and vacant orbital acceptors (tin(IV) tetrachloride and zinc chloride). The positron annihilation lifetime parameters were found to be dependent on the structure, electronic configuration, the power of acceptors and molecular weight of the CT complexes. The positron annihilation lifetime spectroscopy can be used as a probe for the formation of charge-transfer (CT) complexes.

Optical Imaging and Spectroscopic Characterization of Self-Assembled Environmental Adsorbates on Graphene

DOE PAGES

Gallagher, Patrick; Li, Yilei; Watanabe, Kenji; ...

2018-03-28

Topographic studies using scanning probes have found that graphene surfaces are often covered by micron-scale domains of periodic stripes with a 4 nm pitch. These stripes have been variously interpreted as structural ripples or as self-assembled adsorbates. We show that the stripe domains are optically anisotropic by imaging them using a polarization-contrast technique. Optical spectra between 1.1 and 2.8 eV reveal that the anisotropy in the in-plane dielectric function is predominantly real, reaching 0.6 for an assumed layer thickness of 0.3 nm. Furthermore, the spectra are incompatible with a rippled graphene sheet but would be quantitatively explained by the self-assemblymore » of chainlike organic molecules into nanoscale stripes.« less

Hydroxycinnamic acid-derived polymers constitute the polyaromatic domain of suberin

NASA Technical Reports Server (NTRS)

Bernards, M. A.; Lopez, M. L.; Zajicek, J.; Lewis, N. G.

1995-01-01

Suberin is an abundant, complex, intractable, plant cell wall polymeric network that forms both protective and wound-healing layers. Its function is, therefore, critical to the survival of all vascular plants. Its chemical structure and biosynthesis are poorly defined, although it is known to consist of both aromatic and aliphatic domains. While the composition of the aliphatic component has been fairly well characterized, that of the phenolic component has not. Using a combination of specific carbon-13 labeling techniques, and in situ solid state 13C NMR spectroscopic analysis, we now provide the first direct evidence for the nature of the phenolic domain of suberin and report here that it is almost exclusively comprised of a covalently linked, hydroxycinnamic acid-derived polymeric matrix.

Synthesis, spectral features and biological activity of some novel hetarylazo dyes derived from 6-amino-1,3-dimethyluracil

NASA Astrophysics Data System (ADS)

Yousefi, Hessamoddin; Yahyazadeh, Asieh; Yazdanbakhsh, Mohammad Reza; Rassa, Mehdi; Moradi-e-Rufchahi, Enayat O.'llah

2012-05-01

A series of hetarylazoaminouracil dyes were prepared by coupling of 6-amino-1,3-dimethyluracil with eight diazotized heterocyclic amines in nitrosyl sulphuric acid. The prepared azo dyes were characterized by UV-Vis, FT-IR, 13C NMR, 1H NMR spectroscopic techniques and elemental analysis. The solvatochromism of dyes was evaluated with respect to wavelength of maximum absorption (λmax) in seven solvents with different polarities: acetic acid, methanol, water, chloroform, acetonitrile, dimethyl sulfoxide and dimethyl formamide. The effects of acid, base and concentration of the dye on the visible absorption spectra were also reported. In addition, the antimicrobial activity of the synthesized dyes was evaluated on Escherichia coli, Bacillus subtilis, Micrococcus leuteus and Pseudomonas aeruginosa.

Non-invasive spectroscopic techniques in the diagnosis of non-melanoma skin cancer

NASA Astrophysics Data System (ADS)

Drakaki, E.; Sianoudis, IA; Zois, EN; Makropoulou, M.; Serafetinides, AA; Dessinioti, C.; Stefanaki, E.; Stratigos, AJ; Antoniou, C.; Katsambas, A.; Christofidou, E.

2017-11-01

The number of non-melanoma skin cancers is increasing worldwide and has become an important health and economic issue. Early detection and treatment of skin cancer can significantly improve patient outcome. Therefore there is an increase in the demand for proper management and effective non-invasive diagnostic modalities in order to avoid relapses or unnecessary treatments. Although the gold standard of diagnosis for non-melanoma skin cancers is biopsy followed by histopathology evaluation, optical non-invasive diagnostic tools have obtained increased attention. Emerging non-invasive or minimal invasive techniques with possible application in the diagnosis of non-melanoma skin cancers include high-definition optical coherence tomography, fluorescence spectroscopy, oblique incidence diffuse reflectance spectrometry among others spectroscopic techniques. Our findings establish how those spectrometric techniques can be used to more rapidly and easily diagnose skin cancer in an accurate and automated manner in the clinic.

Spectroscopic vector analysis for fast pattern quality monitoring

NASA Astrophysics Data System (ADS)

Sohn, Younghoon; Ryu, Sungyoon; Lee, Chihoon; Yang, Yusin

2018-03-01

In semiconductor industry, fast and effective measurement of pattern variation has been key challenge for assuring massproduct quality. Pattern measurement techniques such as conventional CD-SEMs or Optical CDs have been extensively used, but these techniques are increasingly limited in terms of measurement throughput and time spent in modeling. In this paper we propose time effective pattern monitoring method through the direct spectrum-based approach. In this technique, a wavelength band sensitive to a specific pattern change is selected from spectroscopic ellipsometry signal scattered by pattern to be measured, and the amplitude and phase variation in the wavelength band are analyzed as a measurement index of the pattern change. This pattern change measurement technique is applied to several process steps and verified its applicability. Due to its fast and simple analysis, the methods can be adapted to the massive process variation monitoring maximizing measurement throughput.

Synthesis, spectroscopic characterizations, crystal structures and DFT studies of nalidixic acid carbonyl hydrazones derivatives

NASA Astrophysics Data System (ADS)

Bergamini, F. R. G.; Ribeiro, M. A.; Lancellotti, M.; Machado, D.; Miranda, P. C. M. L.; Cuin, A.; Formiga, A. L. B.; Corbi, P. P.

2016-09-01

This article describes the synthesis and characterization of the 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazide (hzd) and six carbonyl hydrazones derivatives of the nalidixic with 1H-pyrrol-2-ylmethylidene (hpyrr), 1H-imidazol-2-ylmethylidene (h2imi), pyridin-2-ylmethylidene (h2py), pyridin-3-ylmethylidene (h3py), pyridin-4-ylmethylidene(h4py) and (2-hydroxyphenyl)methylidene (hsali). The carbonyl hydrazones were characterized by elemental and ESI-QTOF-MS analyses, IR and detailed NMR spectroscopic measurements. The 2D NMR experiments allowed the unambiguous assignment of the hydrogen, carbon and nitrogen atoms, which have not been reported for nalidixic acid carbonyl hydrazone derivatives so far. Crystal structures of hzd and the new carbonyl hydrazones h2imi, hpyrr and h3py were determined by X-ray diffraction studies. Although the synthesis of hzd was reported decades ago, the hzd crystal structure have not been reported yet. Geometric optimizations of all the characterized structures were performed with the aid of DFT studies. Despite the fact that the hydrazones with 2-pyridine carboxylic acid (h2py) and salicyl aldehyde (hsali) were already reported by literature, a detailed spectroscopic study followed by DFT studies are also reported for such compounds in this manuscript. Antimicrobial studies of the compounds are also presented.