The hallmarks of breast cancer by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Abramczyk, H.; Surmacki, J.; Brożek-Płuska, B.; Morawiec, Z.; Tazbir, M.

2009-04-01

This paper presents new biological results on ex vivo breast tissue based on Raman spectroscopy and demonstrates its power as diagnostic tool with the key advantage in breast cancer research. The results presented here demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The goal of the paper is to develop the diagnostic ability of Raman spectroscopy in order to find an optical marker of cancer in the breast tissue. Applications of Raman spectroscopy in breast cancer research are in the early stages of development in the world. To the best of our knowledge, this paper is one of the most statistically reliable reports (1100 spectra, 99 patients) on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

Fabrication and Metrology of High-Precision Foil Mirror Mounting Elements

NASA Technical Reports Server (NTRS)

Schattenburg, Mark L.

2002-01-01

During the period of this Cooperative Agreement, MIT (Massachusetts Institute of Technology) developed advanced methods for applying silicon microstructures for the precision assembly of foil x-ray optics in support of the Constellation-X Spectroscopy X-ray Telescope (SXT) development effort at Goddard Space Flight Center (GSFC). MIT developed improved methods for fabricating and characterizing the precision silicon micro-combs. MIT also developed and characterized assembly tools and several types of metrology tools in order to characterize and reduce the errors associated with precision assembly of foil optics. Results of this effort were published and presented to the scientific community and the GSFC SXT team. A bibliography of papers and presentations is offered.

[Atomic force microscopy: a tool to analyze the viral cycle].

PubMed

Bernaud, Julien; Castelnovo, Martin; Muriaux, Delphine; Faivre-Moskalenko, Cendrine

2015-05-01

Each step of the HIV-1 life cycle frequently involves a change in the morphology and/or mechanical properties of the viral particle or core. The atomic force microscope (AFM) constitutes a powerful tool for characterizing these physical changes at the scale of a single virus. Indeed, AFM enables the visualization of viral capsids in a controlled physiological environment and to probe their mechanical properties by nano-indentation. Finally, AFM force spectroscopy allows to characterize the affinities between viral envelope proteins and cell receptors at the single molecule level. © 2015 médecine/sciences – Inserm.

Evaluating minerals of environmental concern using spectroscopy

USGS Publications Warehouse

Swayze, G.A.; Clark, R.N.; Higgins, C.T.; Kokaly, R.F.; Livo, K. Eric; Hoefen, T.M.; Ong, C.; Kruse, F.A.

2006-01-01

Imaging spectroscopy has been successfully used to aid researchers in characterizing potential environmental impacts posed by acid-rock drainage, ore-processing dust on mangroves, and asbestos in serpentine mineral deposits and urban dust. Many of these applications synergistically combine field spectroscopy with remote sensing data, thus allowing more-precise data calibration, spectral analysis of the data, and verification of mapping. The increased accuracy makes these environmental evaluation tools efficient because they can be used to focus field work on those areas most critical to the research effort. The use of spectroscopy to evaluate minerals of environmental concern pushes current imaging spectrometer technology to its limits; we present laboratory results that indicate the direction for future designs of imaging spectrometers.

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.

Characterization and measurement of polymer wear

NASA Technical Reports Server (NTRS)

Buckley, D. H.; Aron, P. R.

1984-01-01

Analytical tools which characterize the polymer wear process are discussed. The devices discussed include: visual observation of polymer wear with SEM, the quantification with surface profilometry and ellipsometry, to study the chemistry with AES, XPS and SIMS, to establish interfacial polymer orientation and accordingly bonding with QUARTIR, polymer state with Raman spectroscopy and stresses that develop in polymer films using a X-ray double crystal camera technique.

Endogenous synchronous fluorescence spectroscopy (SFS) of basal cell carcinoma-initial study

NASA Astrophysics Data System (ADS)

Borisova, E.; Zhelyazkova, Al.; Keremedchiev, M.; Penkov, N.; Semyachkina-Glushkovskaya, O.; Avramov, L.

2016-01-01

The human skin is a complex, multilayered and inhomogeneous organ with spatially varying optical properties. Analysis of cutaneous fluorescence spectra could be a very complicated task; therefore researchers apply complex mathematical tools for data evaluation, or try to find some specific approaches, that would simplify the spectral analysis. Synchronous fluorescence spectroscopy (SFS) allows improving the spectral resolution, which could be useful for the biological tissue fluorescence characterization and could increase the tumour detection diagnostic accuracy.

Prediction of Ba, Co and Ni for tropical soils using diffuse reflectance spectroscopy and X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Arantes Camargo, Livia; Marques Júnior, José; Reynaldo Ferracciú Alleoni, Luís; Tadeu Pereira, Gener; De Bortoli Teixeira, Daniel; Santos Rabelo de Souza Bahia, Angélica

2017-04-01

Environmental impact assessments may be assisted by spatial characterization of potentially toxic elements (PTEs). Diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF) are rapid, non-destructive, low-cost, prediction tools for a simultaneous characterization of different soil attributes. Although low concentrations of PTEs might preclude the observation of spectral features, their contents can be predicted using spectroscopy by exploring the existing relationship between the PTEs and soil attributes with spectral features. This study aimed to evaluate, in three geomorphic surfaces of Oxisols, the capacity for predicting PTEs (Ba, Co, and Ni) and their spatial variability by means of diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF). For that, soil samples were collected from three geomorphic surfaces and analyzed for chemical, physical, and mineralogical properties, and then analyzed in DRS (visible + near infrared - VIS+NIR and medium infrared - MIR) and XRF equipment. PTE prediction models were calibrated using partial least squares regression (PLSR). PTE spatial distribution maps were built using the values calculated by the calibrated models that reached the best accuracy using geostatistics. PTE prediction models were satisfactorily calibrated using MIR DRS for Ba, and Co (residual prediction deviation - RPD > 3.0), Vis DRS for Ni (RPD > 2.0) and FRX for all the studied PTEs (RPD > 1.8). DRS- and XRF-predicted values allowed the characterization and the understanding of spatial variability of the studied PTEs.

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues

NASA Astrophysics Data System (ADS)

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-12-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics.

Probing defect states in polycrystalline GaN grown on Si(111) by sub-bandgap laser-excited scanning tunneling spectroscopy

NASA Astrophysics Data System (ADS)

Hsiao, F.-M.; Schnedler, M.; Portz, V.; Huang, Y.-C.; Huang, B.-C.; Shih, M.-C.; Chang, C.-W.; Tu, L.-W.; Eisele, H.; Dunin-Borkowski, R. E.; Ebert, Ph.; Chiu, Y.-P.

2017-01-01

We demonstrate the potential of sub-bandgap laser-excited cross-sectional scanning tunneling microscopy and spectroscopy to investigate the presence of defect states in semiconductors. The characterization method is illustrated on GaN layers grown on Si(111) substrates without intentional buffer layers. According to high-resolution transmission electron microscopy and cathodoluminescence spectroscopy, the GaN layers consist of nanoscale wurtzite and zincblende crystallites with varying crystal orientations and hence contain high defect state densities. In order to discriminate between band-to-band excitation and defect state excitations, we use sub-bandgap laser excitation. We probe a clear increase in the tunnel current at positive sample voltages during sub-bandgap laser illumination for the GaN layer with high defect density, but no effect is found for high quality GaN epitaxial layers. This demonstrates the excitation of free charge carriers at defect states. Thus, sub-bandgap laser-excited scanning tunneling spectroscopy is a powerful complimentary characterization tool for defect states.

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.

Raman spectroscopy in biomedicine – non-invasive in vitro analysis of cells and extracellular matrix components in tissues

PubMed Central

Brauchle, Eva; Schenke-Layland, Katja

2013-01-01

Raman spectroscopy is an established laser-based technology for the quality assurance of pharmaceutical products. Over the past few years, Raman spectroscopy has become a powerful diagnostic tool in the life sciences. Raman spectra allow assessment of the overall molecular constitution of biological samples, based on specific signals from proteins, nucleic acids, lipids, carbohydrates, and inorganic crystals. Measurements are non-invasive and do not require sample processing, making Raman spectroscopy a reliable and robust method with numerous applications in biomedicine. Moreover, Raman spectroscopy allows the highly sensitive discrimination of bacteria. Rama spectra retain information on continuous metabolic processes and kinetics such as lipid storage and recombinant protein production. Raman spectra are specific for each cell type and provide additional information on cell viability, differentiation status, and tumorigenicity. In tissues, Raman spectroscopy can detect major extracellular matrix components and their secondary structures. Furthermore, the non-invasive characterization of healthy and pathological tissues as well as quality control and process monitoring of in vitro-engineered matrix is possible. This review provides comprehensive insight to the current progress in expanding the applicability of Raman spectroscopy for the characterization of living cells and tissues, and serves as a good reference point for those starting in the field. PMID:23161832

Application of modern surface analytical tools in the investigation of surface deterioration processes

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1983-01-01

Surface profilometry and scanning electron microscopy were utilized to study changes in the surface of polymers when eroded. The X-ray photoelectron spectroscopy (XPS) and depth profile analysis indicate the corrosion of metal and ceramic surfaces and reveal the diffusion of certain species into the surface to produce a change in mechanical properties. Ion implantation, nitriding and plating and their effects on the surface are characterized. Auger spectroscopy analysis identified morphological properties of coatings applied to surfaces by sputter deposition.

Quantification of joint inflammation in rheumatoid arthritis by time-resolved diffuse optical spectroscopy and tracer kinetic modeling

NASA Astrophysics Data System (ADS)

Ioussoufovitch, Seva; Morrison, Laura B.; Lee, Ting-Yim; St. Lawrence, Keith; Diop, Mamadou

2015-03-01

Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation, which can cause progressive joint damage and disability. Diffuse optical spectroscopy (DOS) and imaging have the potential to become potent monitoring tools for RA. We devised a method that combined time-resolved DOS and tracer kinetics modeling to rapidly and reliably quantify blood flow in the joint. Preliminary results obtained from two animals show that the technique can detect joint inflammation as early as 5 days after onset.

Support effects in catalysis studied by in-situ sum frequency generation vibrational spectroscopy and in-situ x-ray spectroscopies

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

Kennedy, Griffin John

Here, kinetic measurements are paired with in-situ spectroscopic characterization tools to investigate colloidally based, supported Pt catalytic model systems in order to elucidate the mechanisms by which metal and support work in tandem to dictate activity and selectivity. The results demonstrate oxide support materials, while inactive in absence of Pt nanoparticles, possess unique active sites for the selective conversion of gas phase molecules when paired with an active metal catalyst.

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.

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.

Optical Spectroscopy of New Materials

NASA Technical Reports Server (NTRS)

White, Susan M.; Arnold, James O. (Technical Monitor)

1993-01-01

Composites are currently used for a rapidly expanding number of applications including aircraft structures, rocket nozzles, thermal protection of spacecraft, high performance ablative surfaces, sports equipment including skis, tennis rackets and bicycles, lightweight automobile components, cutting tools, and optical-grade mirrors. Composites are formed from two or more insoluble materials to produce a material with superior properties to either component. Composites range from dispersion-hardened alloys to advanced fiber-reinforced composites. UV/VIS and FTIR spectroscopy currently is used to evaluate the bonding between the matrix and the fibers, monitor the curing process of a polymer, measure surface contamination, characterize the interphase material, monitor anion transport in polymer phases, characterize the void formation (voids must be minimized because, like cracks in a bulk material, they lead to failure), characterize the surface of the fiber component, and measure the overall optical properties for energy balances.

Multi-Instrument Characterization of the Surfaces and Materials in Microfabricated, Carbon Nanotube-Templated Thin Layer Chromatography Plates. An Analogy to ‘The Blind Men and the Elephant’

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

Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh

Herein we apply a suite of surface/materials analytical tools to characterize some of the materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, static time-of-flight secondary ion spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy (HIM). Materials characterized include: the Si(100) substrate with native oxide: Si/SiO2, alumina (35 nm) deposited as a diffusion barrier on the Si/SiO2: Si/SiO2/Al2O3, iron (6 nm) thermally evaporated on the Al2O3: Si/SiO2/Al2O3/Fe, the iron film annealed in H2 to make Fe catalyst nanoparticles: Si/SiO2/Al2O3/Fe(NP),more » and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO2/Al2O3/Fe(NP)/CNT. The Fe thin films and nanoparticles are found in an oxidized state. Some of the analyses of the CNTs/CNT forests reported appear to be unique: the CNT forest appears to exhibit an interesting ‘channeling’ phenomenon by RBS, we observe an odd-even effect in the ToF-SIMS spectra of Cn- species for n = 1 – 6, with ions at even n showing greater intensity than the neighboring signals, and ions with n ≥ 6 showing a steady decrease in intensity, and valence band characterization of CNTs using X-radiation is reported. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of ‘The Blind Men and the Elephant’. (Of course there is increasing emphasis on the use of multiple characterization tools in surface and materials analysis.) The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.« less

Anti-flammable properties of capable phosphorus-nitrogen containing triazine derivatives on cotton

USDA-ARS?s Scientific Manuscript database

Most of new phosphorus-nitrogen containing compounds were prepared by organic reactions of cyanuric chloride and phosphonates. They were characterized by analytical tools such as proton (1H), carbon (13C), and phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy and elemental analysis (EA)...

Discovery and Characterization of Small Planets from the K2 Mission

NASA Astrophysics Data System (ADS)

Howard, Andrew

The K2 mission offers a unique opportunity to find substantial numbers of new transiting planets with host stars much brighter than those found by Kepler -- ideal targets for measurements of planetary atmospheres (with HST and JWST) and planetary masses and densities (with Doppler spectroscopy). The K2 data present unique challenges compared to the Kepler mission. We propose to build on our team's demonstrated successes with the Kepler photometry and in finding exciting new planetary systems in K2 data. We will search for transiting planets in photometry of all stellar K2 targets in each of the first three K2 Campaigns (Fields C0, C1, and C2). We will adapt and enhance our TERRA transit search tool to detect transits in the K2 photometry, and we will assess candidate transiting planets with a suite of K2-specific vetting tools including pixel-level inspection for transit localization, centroid motion tests, and secondary eclipse searches. We will publicly release TERRA and our pixel-level diagnostics for use by other teams in future analyses of K2 and TESS photometry. We will also develop FreeBLEND, a free and open source tool to robustly quantify the probability of false positive detections for individual planet candidates given reduced photometry, constraints from the K2 pixel-level data, adaptive optics imaging, high-resolution stellar spectroscopy, and radial velocity measurements. This tool will be similar to BLENDER for Kepler, but (a) more computationally efficient and useable on the wide range of galactic latitudes that K2 samples and (b) available for use by the entire community. With these tools we will publicly release high-quality (low-noise) reduced photometry of the K2 target stars as well as catalogs of the transiting planets. Host stars in our planet catalogs will be characterized by medium and high-resolution spectroscopy (as appropriate) to yield accurate planet parameters. For a handful of planets in the sample, we will measure masses using Keck-HIRES to constrain the planets' bulk densities and compositions. This project is relevant to the ADA Program as it focuses on archived K2 mission data. It supports NASA's strategic goals to characterize the diverse population of small exoplanets, identified targets to maximize JWST's exoplanet science yield, and develops community tools for use with K2, TESS, and other future missions.

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues.

PubMed

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-10-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Optical fiber Raman-based spectroscopy for oral lesions characterization: a pilot study

NASA Astrophysics Data System (ADS)

Carvalho, Luis Felipe C. S.; Neto, Lázaro P. M.; Oliveira, Inajara P.; Rangel, João. Lucas; Ferreira, Isabelle; Kitakawa, Dárcio; Martin, Airton A.

2016-03-01

In the clinical daily life various lesions of the oral cavity have shown different aspects, generating an inconclusive or doubtful diagnosis. In general, oral injuries are diagnosed by histopathological analysis from biopsy, which is an invasive procedure and does not gives immediate results. In the other hand, Raman spectroscopy technique it is a real time and minimal invasive analytical tool, with notable diagnostic capability. This study aims to characterize, by optical fiber Raman-based spectroscopy (OFRS), normal, inflammatory, potentially malignant, benign and malign oral lesions. Raman data were collected by a Holospec f / 1.8 spectrograph (Kayser Optical Systems) coupled to an optical fiber, with a 785nm laser line source and a CCD Detector. The data were pre-processed and vector normalized. The average analysis and standard deviation was performed associated with cluster analysis and compared to the histopalogical results. Samples of described oral pathological processes were used in the study. The OFRS was efficient to characterized oral lesions and normal mucosa, in which biochemical information related to vibrational modes of proteins, lipids, nucleic acids and carbohydrates were observed. The technique (OFRS) is able to demonstrate biochemical information concern different types of oral lesions showing that Raman spectroscopy could be useful for an early and minimal invasive diagnosis.

In vivo characterization of colorectal metastases in human liver using diffuse reflectance spectroscopy: toward guidance in oncological procedures

NASA Astrophysics Data System (ADS)

Spliethoff, Jarich W.; de Boer, Lisanne L.; Meier, Mark A. J.; Prevoo, Warner; de Jong, Jeroen; Kuhlmann, Koert; Bydlon, Torre M.; Sterenborg, Henricus J. C. M.; Hendriks, Benno H. W.; Ruers, Theo J. M.

2016-09-01

There is a strong need to develop clinical instruments that can perform rapid tissue assessment at the tip of smart clinical instruments for a variety of oncological applications. This study presents the first in vivo real-time tissue characterization during 24 liver biopsy procedures using diffuse reflectance (DR) spectroscopy at the tip of a core biopsy needle with integrated optical fibers. DR measurements were performed along each needle path, followed by biopsy of the target lesion using the same needle. Interventional imaging was coregistered with the DR spectra. Pathology results were compared with the DR spectroscopy data at the final measurement position. Bile was the primary discriminator between normal liver tissue and tumor tissue. Relative differences in bile content matched with the tissue diagnosis based on histopathological analysis in all 24 clinical cases. Continuous DR measurements during needle insertion in three patients showed that the method can also be applied for biopsy guidance or tumor recognition during surgery. This study provides an important validation step for DR spectroscopy-based tissue characterization in the liver. Given the feasibility of the outlined approach, it is also conceivable to make integrated fiber-optic tools for other clinical procedures that rely on accurate instrument positioning.

Current Advances in the Application of Raman Spectroscopy for Molecular Diagnosis of Cervical Cancer

PubMed Central

Ramos, Inês Raquel Martins; Malkin, Alison; Lyng, Fiona Mary

2015-01-01

Raman spectroscopy provides a unique biochemical fingerprint capable of identifying and characterizing the structure of molecules, cells, and tissues. In cervical cancer, it is acknowledged as a promising biochemical tool due to its ability to detect premalignancy and early malignancy stages. This review summarizes the key research in the area and the evidence compiled is very encouraging for ongoing and further research. In addition to the diagnostic potential, promising results for HPV detection and monitoring treatment response suggest more than just a diagnosis prospective. A greater body of evidence is however necessary before Raman spectroscopy is fully validated for clinical use and larger comprehensive studies are required to fully establish the role of Raman spectroscopy in the molecular diagnostics of cervical cancer. PMID:26180802

Nanoscale visualization and characterization of Myxococcus xanthus cells with atomic force microscopy

PubMed Central

Pelling, Andrew E.; Li, Yinuo; Shi, Wenyuan; Gimzewski, James K.

2005-01-01

Multicellular microbial communities are the predominant form of existence for microorganisms in nature. As one of the most primitive social organisms, Myxococcus xanthus has been an ideal model bacterium for studying intercellular interaction and multicellular organization. Through previous genetic and EM studies, various extracellular appendages and matrix components have been found to be involved in the social behavior of M. xanthus, but none of them was directly visualized and analyzed under native conditions. Here, we used atomic force microscopy (AFM) imaging and in vivo force spectroscopy to characterize these cellular structures under native conditions. AFM imaging revealed morphological details on the extracellular ultrastructures at an unprecedented resolution, and in vivo force spectroscopy of live cells in fluid allowed us to nanomechanically characterize extracellular polymeric substances. The findings provide the basis for AFM as a useful tool for investigating microbial-surface ultrastructures and nanomechanical properties under native conditions. PMID:15840722

Quantitative structure parameters from the NMR spectroscopy of quadrupolar nuclei

DOE PAGES

Perras, Frederic A.

2015-12-15

Here, nuclear magnetic resonance (NMR) spectroscopy is one of the most important characterization tools in chemistry, however, 3/4 of the NMR active nuclei are underutilized due to their quadrupolar nature. This short review centers on the development of methods that use solid-state NMR of quadrupolar nuclei for obtaining quantitative structural information. Namely, techniques using dipolar recoupling as well as the resolution afforded by double-rotation are presented for the measurement of spin–spin coupling between quadrupoles, enabling the measurement of internuclear distances and connectivities.

Rapid detection of foodborne microorganisms on food surface using Fourier transform Raman spectroscopy

NASA Astrophysics Data System (ADS)

Yang, Hong; Irudayaraj, Joseph

2003-02-01

Fourier transform (FT) Raman spectroscopy was used for non-destructive characterization and differentiation of six different microorganisms including the pathogen Escherichia coli O157:H7 on whole apples. Mahalanobis distance metric was used to evaluate and quantify the statistical differences between the spectra of six different microorganisms. The same procedure was extended to discriminate six different strains of E. coli. The FT-Raman procedure was not only successful in discriminating the different E. coli strain but also accurately differentiated the pathogen from non-pathogens. Results demonstrate that FT-Raman spectroscopy can be an excellent tool for rapid examination of food surfaces for microorganism contamination and for the classification of microbial cultures.

High resolution spectroscopy in the microwave and far infrared

NASA Technical Reports Server (NTRS)

Pickett, Herbert M.

1990-01-01

High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

Metalloproteomics: Forward and Reverse Approaches in Metalloprotein Structural and Functional Characterization

PubMed Central

Shi, Wuxian; Chance, Mark R.

2010-01-01

About one-third of all proteins are associated with a metal. Metalloproteomics is defined as the structural and functional characterization of metalloproteins on a genome-wide scale. The methodologies utilized in metalloproteomics, including both forward (bottom-up) and reverse (top-down) technologies, to provide information on the identity, quantity and function of metalloproteins are discussed. Important techniques frequently employed in metalloproteomics include classical proteomics tools such as mass spectrometry and 2-D gels, immobilized-metal affinity chromatography, bioinformatics sequence analysis and homology modeling, X-ray absorption spectroscopy and other synchrotron radiation based tools. Combinative applications of these techniques provide a powerful approach to understand the function of metalloproteins. PMID:21130021

Semi-quantitative analysis of FT-IR spectra of humic fractions of nine US soils

USDA-ARS?s Scientific Manuscript database

Fourier Transform Infrared Spectroscopy (FT-IR) is a simple and fast tool for characterizing soil organic matter. However, most FT-IR spectra are only analyzed qualitatively. In this work, we prepared mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) from nine soils collected from six ...

Diagnosis of meningioma by time-resolved fluorescence spectroscopy.

PubMed

Butte, Pramod V; Pikul, Brian K; Hever, Aviv; Yong, William H; Black, Keith L; Marcu, Laura

2005-01-01

We investigate the use of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) as an adjunctive tool for the intraoperative rapid evaluation of tumor specimens and delineation of tumor from surrounding normal tissue. Tissue autofluorescence is induced with a pulsed nitrogen laser (337 nm, 1.2 ns) and the intensity decay profiles are recorded in the 370 to 500 nm spectral range with a fast digitizer (0.2 ns resolution). Experiments are conducted on excised specimens (meningioma, dura mater, cerebral cortex) from 26 patients (97 sites). Spectral intensities and time-dependent parameters derived from the time-resolved spectra of each site are used for tissue characterization. A linear discriminant analysis algorithm is used for tissue classification. Our results reveal that meningioma is characterized by unique fluorescence characteristics that enable discrimination of tumor from normal tissue with high sensitivity (>89%) and specificity (100%). The accuracy of classification is found to increase (92.8% cases in the training set and 91.8% in the cross-validated set correctly classified) when parameters from both the spectral and the time domain are used for discrimination. Our findings establish the feasibility of using TR-LIFS as a tool for the identification of meningiomas and enables further development of real-time diagnostic tools for analyzing surgical tissue specimens of meningioma or other brain tumors.

Diagnosis of meningioma by time-resolved fluorescence spectroscopy

PubMed Central

Butte, Pramod V.; Pikul, Brian K.; Hever, Aviv; Yong, William H.; Black, Keith L.; Marcu, Laura

2010-01-01

We investigate the use of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) as an adjunctive tool for the intraoperative rapid evaluation of tumor specimens and delineation of tumor from surrounding normal tissue. Tissue autofluorescence is induced with a pulsed nitrogen laser (337 nm, 1.2 ns) and the intensity decay profiles are recorded in the 370 to 500 nm spectral range with a fast digitizer (0.2 ns resolution). Experiments are conducted on excised specimens (meningioma, dura mater, cerebral cortex) from 26 patients (97 sites). Spectral intensities and time-dependent parameters derived from the time-resolved spectra of each site are used for tissue characterization. A linear discriminant analysis algorithm is used for tissue classification. Our results reveal that meningioma is characterized by unique fluorescence characteristics that enable discrimination of tumor from normal tissue with high sensitivity (>89%) and specificity (100%). The accuracy of classification is found to increase (92.8% cases in the training set and 91.8% in the cross-validated set correctly classified) when parameters from both the spectral and the time domain are used for discrimination. Our findings establish the feasibility of using TR-LIFS as a tool for the identification of meningiomas and enables further development of real-time diagnostic tools for analyzing surgical tissue specimens of meningioma or other brain tumors. PMID:16409091

Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

PubMed

Ghosal, Sutapa; Wagner, Jeff

2013-07-07

We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

Characterizing monoclonal antibody formulations in arginine glutamate solutions using 1H NMR spectroscopy

PubMed Central

Kheddo, Priscilla; Cliff, Matthew J.; Uddin, Shahid; van der Walle, Christopher F.; Golovanov, Alexander P.

2016-01-01

ABSTRACT Assessing how excipients affect the self-association of monoclonal antibodies (mAbs) requires informative and direct in situ measurements for highly concentrated solutions, without sample dilution or perturbation. This study explores the application of solution nuclear magnetic resonance (NMR) spectroscopy for characterization of typical mAb behavior in formulations containing arginine glutamate. The data show that the analysis of signal intensities in 1D 1H NMR spectra, when compensated for changes in buffer viscosity, is invaluable for identifying conditions where protein-protein interactions are minimized. NMR-derived molecular translational diffusion rates for concentrated solutions are less useful than transverse relaxation rates as parameters defining optimal formulation. Furthermore, NMR reports on the solution viscosity and mAb aggregation during accelerated stability study assessment, generating data consistent with that acquired by size-exclusion chromatography. The methodology developed here offers NMR spectroscopy as a new tool providing complementary information useful to formulation development of mAbs and other large therapeutic proteins. PMID:27589351

Generation and characterization of ultrathin free-flowing liquid sheets

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

Koralek, Jake D.; Kim, Jongjin B.; Bruza, Petr

The physics and chemistry of liquid solutions play a central role in science, and our understanding of life on Earth. Unfortunately, key tools for interrogating aqueous systems, such as infrared and soft X-ray spectroscopy, cannot readily be applied because of strong absorption in water. Here we use gas-dynamic forces to generate free-flowing, sub-micron, liquid sheets which are two orders of magnitude thinner than anything previously reported. Optical, infrared, and X-ray spectroscopies are used to characterize the sheets, which are found to be tunable in thickness from over 1 μm down to less than 20 nm, which corresponds to fewer thanmore » 100 water molecules thick. At this thickness, aqueous sheets can readily transmit photons across the spectrum, leading to potentially transformative applications in infrared, X-ray, electron spectroscopies and beyond. Lastly, the ultrathin sheets are stable for days in vacuum, and we demonstrate their use at free-electron laser and synchrotron light sources.« less

Characterizing monoclonal antibody formulations in arginine glutamate solutions using 1H NMR spectroscopy.

PubMed

Kheddo, Priscilla; Cliff, Matthew J; Uddin, Shahid; van der Walle, Christopher F; Golovanov, Alexander P

2016-10-01

Assessing how excipients affect the self-association of monoclonal antibodies (mAbs) requires informative and direct in situ measurements for highly concentrated solutions, without sample dilution or perturbation. This study explores the application of solution nuclear magnetic resonance (NMR) spectroscopy for characterization of typical mAb behavior in formulations containing arginine glutamate. The data show that the analysis of signal intensities in 1D 1 H NMR spectra, when compensated for changes in buffer viscosity, is invaluable for identifying conditions where protein-protein interactions are minimized. NMR-derived molecular translational diffusion rates for concentrated solutions are less useful than transverse relaxation rates as parameters defining optimal formulation. Furthermore, NMR reports on the solution viscosity and mAb aggregation during accelerated stability study assessment, generating data consistent with that acquired by size-exclusion chromatography. The methodology developed here offers NMR spectroscopy as a new tool providing complementary information useful to formulation development of mAbs and other large therapeutic proteins.

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.

Generation and characterization of ultrathin free-flowing liquid sheets

DOE PAGES

Koralek, Jake D.; Kim, Jongjin B.; Bruza, Petr; ...

2018-04-10

The physics and chemistry of liquid solutions play a central role in science, and our understanding of life on Earth. Unfortunately, key tools for interrogating aqueous systems, such as infrared and soft X-ray spectroscopy, cannot readily be applied because of strong absorption in water. Here we use gas-dynamic forces to generate free-flowing, sub-micron, liquid sheets which are two orders of magnitude thinner than anything previously reported. Optical, infrared, and X-ray spectroscopies are used to characterize the sheets, which are found to be tunable in thickness from over 1 μm down to less than 20 nm, which corresponds to fewer thanmore » 100 water molecules thick. At this thickness, aqueous sheets can readily transmit photons across the spectrum, leading to potentially transformative applications in infrared, X-ray, electron spectroscopies and beyond. Lastly, the ultrathin sheets are stable for days in vacuum, and we demonstrate their use at free-electron laser and synchrotron light sources.« less

Versatile silicon-waveguide supercontinuum for coherent mid-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Nader, Nima; Maser, Daniel L.; Cruz, Flavio C.; Kowligy, Abijith; Timmers, Henry; Chiles, Jeff; Fredrick, Connor; Westly, Daron A.; Nam, Sae Woo; Mirin, Richard P.; Shainline, Jeffrey M.; Diddams, Scott

2018-03-01

Laser frequency combs, with their unique combination of precisely defined spectral lines and broad bandwidth, are a powerful tool for basic and applied spectroscopy. Here, we report offset-free, mid-infrared frequency combs and dual-comb spectroscopy through supercontinuum generation in silicon-on-sapphire waveguides. We leverage robust fabrication and geometrical dispersion engineering of nanophotonic waveguides for multi-band, coherent frequency combs spanning 70 THz in the mid-infrared (2.5 μm-6.2 μm). Precise waveguide fabrication provides significant spectral broadening with engineered spectra targeted at specific mid-infrared bands. We characterize the relative-intensity-noise of different bands and show that the measured levels do not pose any limitation for spectroscopy applications. Additionally, we use the fabricated photonic devices to demonstrate dual-comb spectroscopy of a carbonyl sulfide gas sample at 5 μm. This work forms the technological basis for applications such as point sensors for fundamental spectroscopy, atmospheric chemistry, trace and hazardous gas detection, and biological microscopy.

High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

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

Rocker, J.; Cornu, D.; Kieseritzky, E.

2014-08-01

A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of themore » resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic species with a density of approximately 5 × 10{sup 11} spins/cm{sup 2}, which is comparable to the limit obtained for the presently available UHV-EPR spectrometer operating at 10 GHz (X-band). Investigation of electron trapped centers in MgO(001) films shows that the increased resolution offered by the experiments at W-band allows to identify new paramagnetic species, that cannot be differentiated with the currently available methodology.« less

A novel analytical method for pharmaceutical polymorphs by terahertz spectroscopy and the optimization of crystal form at the discovery stage.

PubMed

Ikeda, Yukihiro; Ishihara, Yoko; Moriwaki, Toshiya; Kato, Eiji; Terada, Katsuhide

2010-01-01

A novel analytical method for the determination of pharmaceutical polymorphs was developed using terahertz spectroscopy. It was found out that each polymorph of a substance showed a specific terahertz absorption spectrum. In particular, analysis of the second derivative spectrum was enormously beneficial in the discrimination of closely related polymorphs that were difficult to discern by powder X-ray diffractometry. Crystal forms that were obtained by crystallization from various solvents and stored under various conditions were specifically characterized by the second derivative of each terahertz spectrum. Fractional polymorphic transformation for substances stored under stressed conditions was also identified by terahertz spectroscopy during solid-state stability test, but could not be detected by powder X-ray diffractometry. Since polymorphs could be characterized clearly by terahertz spectroscopy, further physicochemical studies could be conducted in a timely manner. The development form of compound examined was determined by the results of comprehensive physicochemical studies that included thermodynamic relationships, as well as chemical and physicochemical stability. In conclusion, terahertz spectroscopy, which has unique power in the elucidation of molecular interaction within a crystal lattice, can play more important role in physicochemical research. Terahertz spectroscopy has a great potential as a tool for polymorphic determination, particularly since the second derivative of the terahertz spectrum possesses high sensitivity for pharmaceutical polymorphs.

Characterizing the hydration state of L-threonine in solution using terahertz time-domain attenuated total reflection spectroscopy

NASA Astrophysics Data System (ADS)

Huang, Huachuan; Liu, Qiao; Zhu, Liguo; Li, Zeren

2018-01-01

The hydration of biomolecules is closely related to the dynamic process of their functional expression, therefore, characterizing hydration phenomena is a subject of keen interest. However, direct measurements on the global hydration state of biomolecules couldn't have been acquired using traditional techniques such as thermodynamics, ultrasound, microwave spectroscopy or viscosity, etc. In order to realize global hydration characterization of amino acid such as L-threonine, terahertz time-domain attenuated total reflectance spectroscopy (THz-TDS-ATR) was adopted in this paper. By measuring the complex permittivity of L-threonine solutions with various concentrations in the THz region, the hydration state and its concentration dependence were obtained, indicating that the number of hydrous water decreased with the increase of concentration. The hydration number was evaluated to be 17.8 when the molar concentration of L-threonine was 0.34 mol/L, and dropped to 13.2 when the molar concentration increased to 0.84 mol/L, when global hydration was taken into account. According to the proposed direct measurements, it is believed that the THz-TDS-ATR technique is a powerful tool for studying the picosecond molecular dynamics of amino acid solutions.

Investigation of hydrogenation of toluene to methylcyclohexane in a trickle bed reactor by low-field nuclear magnetic resonance spectroscopy.

PubMed

Guthausen, Gisela; von Garnier, Agnes; Reimert, Rainer

2009-10-01

Low-field nuclear magnetic resonance (NMR) spectroscopy is applied to study the hydrogenation of toluene in a lab-scale reactor. A conventional benchtop NMR system was modified to achieve chemical shift resolution. After an off-line validity check of the approach, the reaction product is analyzed on-line during the process, applying chemometric data processing. The conversion of toluene to methylcyclohexane is compared with off-line gas chromatographic analysis. Both classic analytical and chemometric data processing was applied. As the results, which are obtained within a few tens of seconds, are equivalent within the experimental accuracy of both methods, low-field NMR spectroscopy was shown to provide an analytical tool for reaction characterization and immediate feedback.

Speciation and Sources of Brown Carbon in Precipitation at Seoul, Korea: Insights from Excitation-Emission Matrix Spectroscopy and Carbon Isotopic Analysis.

PubMed

Yan, Ge; Kim, Guebuem

2017-10-17

Brown carbon (BrC) plays a significant role in the Earth's radiative balance, yet its sources and chemical composition remain poorly understood. In this work, we investigated BrC in the atmospheric environment of Seoul by characterizing dissolved organic matter in precipitation using excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). The two independent fluorescent components identified by PARAFAC were attributed to humic-like substance (HULIS) and biologically derived material based on their significant correlations with measured HULIS isolated using solid-phase extraction and total hydrolyzable tyrosine. The year-long observation shows that HULIS contributes to 66 ± 13% of total fluorescence intensity of our samples on average. By using dual carbon ( 13 C and 14 C) isotopic analysis conducted on isolated HULIS, the HULIS fraction of BrC was found to be primarily derived from biomass burning and emission of terrestrial biogenic gases and particles (>70%), with minor contributions from fossil-fuel combustion. The knowledge derived from this study could contribute to the establishment of a characterizing system of BrC components identified by EEM spectroscopy. Our work demonstrates that, EEM fluorescence spectroscopy is a powerful tool in BrC study, on the basis of its chromophore resolving power, allowing investigation into individual components of BrC by other organic matter characterization techniques.

Micro-Raman spectroscopy as a tool for the characterization of silicon carbide in power semiconductor material processing

NASA Astrophysics Data System (ADS)

De Biasio, M.; Kraft, M.; Schultz, M.; Goller, B.; Sternig, D.; Esteve, R.; Roesner, M.

2017-05-01

Silicon carbide (SiC) is a wide band-gap semi-conductor material that is used increasingly for high voltage power devices, since it has a higher breakdown field strength and better thermal conductivity than silicon. However, in particular its hardness makes wafer processing difficult and many standard semi-conductor processes have to be specially adapted. We measure the effects of (i) mechanical processing (i.e. grinding of the backside) and (ii) chemical and thermal processing (i.e. doping and annealing), using confocal microscopy to measure the surface roughness of ground wafers and micro-Raman spectroscopy to measure the stresses induced in the wafers by grinding. 4H-SiC wafers with different dopings were studied before and after annealing, using depth-resolved micro-Raman spectroscopy to observe how doping and annealing affect: i.) the damage and stresses induced on the crystalline structure of the samples and ii.) the concentration of free electrical carriers. Our results show that mechanical, chemical and thermal processing techniques have effects on this semiconductor material that can be observed and characterized using confocal microscopy and high resolution micro Raman spectroscopy.

Modern Material Analysis Instruments Add a New Dimension to Materials Characterization and Failure Analysis

NASA Technical Reports Server (NTRS)

Panda, Binayak

2009-01-01

Modern analytical tools can yield invaluable results during materials characterization and failure analysis. Scanning electron microscopes (SEMs) provide significant analytical capabilities, including angstrom-level resolution. These systems can be equipped with a silicon drift detector (SDD) for very fast yet precise analytical mapping of phases, as well as electron back-scattered diffraction (EBSD) units to map grain orientations, chambers that admit large samples, variable pressure for wet samples, and quantitative analysis software to examine phases. Advanced solid-state electronics have also improved surface and bulk analysis instruments: Secondary ion mass spectroscopy (SIMS) can quantitatively determine and map light elements such as hydrogen, lithium, and boron - with their isotopes. Its high sensitivity detects impurities at parts per billion (ppb) levels. X-ray photo-electron spectroscopy (XPS) can determine oxidation states of elements, as well as identifying polymers and measuring film thicknesses on coated composites. This technique is also known as electron spectroscopy for chemical analysis (ESCA). Scanning Auger electron spectroscopy (SAM) combines surface sensitivity, spatial lateral resolution (10 nm), and depth profiling capabilities to describe elemental compositions of near and below surface regions down to the chemical state of an atom.

An Assessment of macro-scale in situ Raman and ultraviolet-induced fluorescence spectroscopy for rapid characterization of frozen peat and ground ice

NASA Astrophysics Data System (ADS)

Laing, Janelle R.; Robichaud, Hailey C.; Cloutis, Edward A.

2016-04-01

The search for life on other planets is an active area of research. Many of the likeliest planetary bodies, such as Europa, Enceladus, and Mars are characterized by cold surface environments and ice-rich terrains. Both Raman and ultraviolet-induced fluorescence (UIF) spectroscopies have been proposed as promising tools for the detection of various kinds of bioindicators in these environments. We examined whether macro-scale Raman and UIF spectroscopy could be applied to the analysis of unprocessed terrestrial frozen peat and clear ground ice samples for detection of bioindicators. It was found that this approach did not provide unambiguous detection of bioindicators, likely for a number of reasons, particularly due to strong broadband induced fluorescence. Other contributing factors may include degradation of organic matter in frozen peat to the point that compound-specific emitted fluorescence or Raman peaks were not resolvable. Our study does not downgrade the utility of either UIF or Raman spectroscopy for astrobiological investigations (which has been demonstrated in previous studies), but does suggest that the choice of instrumentation, operational conditions and sample preparation are important factors in ensuring the success of these techniques.

The Optical Absorption Coefficient of Maize Grains Investigated by Photoacoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Rodríguez-Páez, C. L.; Carballo-Carballo, A.; Rico-Molina, R.; Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Moreno-Martínez, E.

2017-01-01

In the maize and tortilla industry, it is important to characterize the color of maize ( Zea mays L.) grain, as it is one of the attributes that directly affect the quality of the tortillas consumed by the population. For this reason, the availability of alternative techniques for assessing and improving the quality of grain is valued. Photoacoustic spectroscopy has proven to be a useful tool for characterizing maize grain. So, the objective of the present study was to determine the optical absorption coefficient β of the maize grain used to make tortillas from two regions of Mexico: (a) Valles Altos, 2012-2013 production cycle and (b) Guasave, Sinaloa, 2013-2014 production cycle. Traditional reflectance measurements, physical characteristics of the grain and nutrient content were also calculated. The experimental results show different characteristics for maize grains.

Electroluminescence and other diagnostic techniques for the study of hot-electron effects in compound semiconductor devices

NASA Astrophysics Data System (ADS)

Zanoni, Enrico; Meneghesso, Gaudenzio; Menozzi, Roberto

2000-03-01

Hot electron in III-V FETs can be indirectly monitored by measuring the current coming out from the gate when the device is biased at high electric fields. This negative current is due to the collection of holes generated by impact ionization in the gate-to drain region. Electroluminescence represents a powerful tool in order to characterize not only hot electrons but also material properties. By using spatially resolved emission microscopy it is possible to show that the light due to cold electron/hole recombination is emitted between the gate and the source (low electric field region), while the contribution due to hot electrons is emitted between the gate and the drain (high electric field region). Deep-traps created in the device by hot carriers can be analysed by means of drain current deep level transient spectroscopy and by transconductance frequency dispersion. Cathodoluminescence, optical beam induced current, X-ray spectroscopy, electron energy loss spectroscopy in combination with a transmission electron microscopy are powerful tools in order to identify and localize surface modification following hot-electron stress tests.

Microanalysis of tool steel and glass with laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Loebe, Klaus; Uhl, Arnold; Lucht, Hartmut

2003-10-01

A laser microscope system for the microanalytical characterization of complex materials is described. The universal measuring principle of laser-induced breakdown spectroscopy (LIBS) in combination with echelle optics permits a fast simultaneous multielement analysis with a possible spatial resolution below 10 pm. The developed system features completely UV-transparent optics for the laser-microscope coupling and the emission beam path and enables parallel signal detection within the wavelength range of 200-800 nm with a spectral resolution of a few picometers. Investigations of glass defects and tool steels were performed. The characterization of a glass defect in a tumbler by a micro-LIBS line scan, with use of a 266-nm diode-pumped Nd:YAG laser for excitation, is possible by simple comparison of plasma spectra of the defect and the surrounding area. Variations in the main elemental composition as well as impurities by trace elements are detected at the same time. Through measurement of the calibration samples with the known concentration of the corresponding element, a correlation between the intensity of spectral lines and the element concentration was also achieved. The change of elemental composition at the transient stellite solder of tool steels has been determined by an area scan. The two-dimensional pictures show abrupt changes of the element distribution along the solder edge and allow fundamental researches of dynamic modifications (e.g., diffusion) in steel.

The characterization of natural gemstones using non-invasive FT-IR spectroscopy: New data on tourmalines.

PubMed

Mercurio, Mariano; Rossi, Manuela; Izzo, Francesco; Cappelletti, Piergiulio; Germinario, Chiara; Grifa, Celestino; Petrelli, Maurizio; Vergara, Alessandro; Langella, Alessio

2018-02-01

Fourteen samples of tourmaline from the Real Museo Mineralogico of Federico II University (Naples) have been characterized through multi-methodological investigations (EMPA-WDS, SEM-EDS, LA-ICP-MS, and FT-IR spectroscopy). The samples show different size, morphology and color, and are often associated with other minerals. Data on major and minor elements allowed to identify and classify tourmalines as follows: elbaites, tsilaisite, schorl, dravites, uvites and rossmanite. Non-invasive, non-destructive FT-IR and in-situ analyses were carried out on the same samples to validate this chemically-based identification and classification. The results of this research show that a complete characterization of this mineral species, usually time-consuming and expensive, can be successfully achieved through non-destructive FT-IR technique, thus representing a reliable tool for a fast classification extremely useful to plan further analytical strategies, as well as to support gemological appraisals. Copyright © 2017 Elsevier B.V. All rights reserved.

Advances in the in Vivo Raman Spectroscopy of Malignant Skin Tumors Using Portable Instrumentation

PubMed Central

Kourkoumelis, Nikolaos; Balatsoukas, Ioannis; Moulia, Violetta; Elka, Aspasia; Gaitanis, Georgios; Bassukas, Ioannis D.

2015-01-01

Raman spectroscopy has emerged as a promising tool for real-time clinical diagnosis of malignant skin tumors offering a number of potential advantages: it is non-intrusive, it requires no sample preparation, and it features high chemical specificity with minimal water interference. However, in vivo tissue evaluation and accurate histopathological classification remain a challenging task for the successful transition from laboratory prototypes to clinical devices. In the literature, there are numerous reports on the applications of Raman spectroscopy to biomedical research and cancer diagnostics. Nevertheless, cases where real-time, portable instrumentations have been employed for the in vivo evaluation of skin lesions are scarce, despite their advantages in use as medical devices in the clinical setting. This paper reviews the advances in real-time Raman spectroscopy for the in vivo characterization of common skin lesions. The translational momentum of Raman spectroscopy towards the clinical practice is revealed by (i) assembling the technical specifications of portable systems and (ii) analyzing the spectral characteristics of in vivo measurements. PMID:26132563

Two states or not two states: Single-molecule folding studies of protein L

NASA Astrophysics Data System (ADS)

Aviram, Haim Yuval; Pirchi, Menahem; Barak, Yoav; Riven, Inbal; Haran, Gilad

2018-03-01

Experimental tools of increasing sophistication have been employed in recent years to study protein folding and misfolding. Folding is considered a complex process, and one way to address it is by studying small proteins, which seemingly possess a simple energy landscape with essentially only two stable states, either folded or unfolded. The B1-IgG binding domain of protein L (PL) is considered a model two-state folder, based on measurements using a wide range of experimental techniques. We applied single-molecule fluorescence resonance energy transfer (FRET) spectroscopy in conjunction with a hidden Markov model analysis to fully characterize the energy landscape of PL and to extract the kinetic properties of individual molecules of the protein. Surprisingly, our studies revealed the existence of a third state, hidden under the two-state behavior of PL due to its small population, ˜7%. We propose that this minority intermediate involves partial unfolding of the two C-terminal β strands of PL. Our work demonstrates that single-molecule FRET spectroscopy can be a powerful tool for a comprehensive description of the folding dynamics of proteins, capable of detecting and characterizing relatively rare metastable states that are difficult to observe in ensemble studies.

Magnetic resonance spectroscopy (MRS) of vertebral column – an additional tool for evaluation of aggressiveness of vertebral haemangioma like lesion

PubMed Central

Jeromel, Miran; Podobnik, Janez

2014-01-01

Background Most vertebral haemangioma are asymptomatic and discovered incidentally. Sometimes the symptomatic lesions present with radiological signs of aggressiveness and their appearance resemble other aggressive lesions (e.g. solitary plasmacytoma). Case report. We present a patient with large symptomatic aggressive haemangioma like lesion in 12th thoracic vertebra in which a magnetic resonance spectroscopy (MRS) was used to analyse fat content within the lesion. The lesion in affected vertebrae showed low fat content with 33% of fat fraction (%FF). The fat content in non-affected (1st lumbar) vertebra was as expected for patient’s age (68%). Based on MRS data, the lesion was characterized as an aggressive haemangioma. The diagnosis was confirmed with biopsy, performed during the treatment – percutaneous vertebroplasty. Conclusions The presented case shows that MRS can be used as an additional tool for evaluation of aggressiveness of vertebral haemangioma like lesions. PMID:24991203

Characterization of Maize Grains with Different Pigmentation Investigated by Photoacoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Rico Molina, R.; Hernández Aguilar, C.; Dominguez Pacheco, A.; Cruz-Orea, A.; López Bonilla, J. L.

2014-10-01

A knowledge of grains' optical parameters is of great relevance in the maize grain technology practice. Such parameters provide information about its absorption and reflectance, which in turn is related to its color. In the dough and tortilla industries, it is important to characterize this attribute of the corn kernel, as it is one of the attributes that directly affects the quality of the food product. Thus, it is important to have techniques that contribute to the characterization of this raw material. It is traditionally characterized by conventional methods, which usually destroy the grain and involve a laborious preparation of material plus they are expensive. The objective of this study was to determine the optical absorption coefficient for maize grains ( Zea mays L.) with different pigmentations by means of photoacoustic spectroscopy (PAS). The genotype A had bluish coloration and genotype B had yellowish coloration. In addition, the photoacoustic signal obtained by two methods was analyzed mathematically: the standard deviation and the first derivative; both results were compared (Fig. 1). In combination with mathematical analysis, PAS may be considered as a potential diagnostic tool for the characterization of the grains. [Figure not available: see fulltext.

Key metabolites in tissue extracts of Elliptio complanata identified using 1H nuclear magnetic resonance spectroscopy

PubMed Central

Hurley-Sanders, Jennifer L.; Levine, Jay F.; Nelson, Stacy A. C.; Law, J. M.; Showers, William J.; Stoskopf, Michael K.

2015-01-01

We used 1H nuclear magnetic resonance spectroscopy to describe key metabolites of the polar metabolome of the freshwater mussel, Elliptio complanata. Principal components analysis documented variability across tissue types and river of origin in mussels collected from two rivers in North Carolina (USA). Muscle, digestive gland, mantle and gill tissues yielded identifiable but overlapping metabolic profiles. Variation in digestive gland metabolic profiles between the two mussel collection sites was characterized by differences in mono- and disaccharides. Variation in mantle tissue metabolomes appeared to be associated with sex. Nuclear magnetic resonance spectroscopy is a sensitive means to detect metabolites in the tissues of E. complanata and holds promise as a tool for the investigation of freshwater mussel health and physiology. PMID:27293708

Characterizing millisecond intermediates in hemoproteins using rapid-freeze-quench resonance Raman spectroscopy.

PubMed

Matsumura, Hirotoshi; Moënne-Loccoz, Pierre

2014-01-01

The combination of rapid freeze quenching (RFQ) with resonance Raman (RR) spectroscopy represents a unique tool with which to investigate the nature of short-lived intermediates formed during the enzymatic reactions of metalloproteins. Commercially available equipment allows trapping of intermediates within a millisecond to second time scale for low-temperature RR analysis resulting in the direct detection of metal-ligand vibrations and porphyrin skeletal vibrations in hemoproteins. This chapter briefly discusses RFQ-RR studies carried out previously in our laboratory and presents, as a practical example, protocols for the preparation of RFQ samples of the reaction of metmyoglobin with nitric oxide (NO) under anaerobic conditions. Also described are important controls and practical procedures for the analysis of these samples by low-temperature RR spectroscopy.

Applications of Raman spectroscopy to gemology.

PubMed

Bersani, Danilo; Lottici, Pier Paolo

2010-08-01

Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals.

Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

NASA Astrophysics Data System (ADS)

García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

2016-12-01

Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

Terahertz spectroscopic investigations of leather in terahertz wave range

NASA Astrophysics Data System (ADS)

Song, Mei-jing; Li, Jiu-sheng

2012-03-01

Pulsed THz time-domain spectroscopy is a coherent technique, in which both the amplitude and the phase of a THz pulse are measured. Recently, material characterization using THz spectroscopy has been applied to biochemicals, pharmaceuticals, polymers and semiconductors and has given us important information. Moreover, THz imaging has progressed and is expected to be applicable for the identification of narcotics and explosives. The most important and characteristic point of THz spectroscopy is said to be its ability to observe intermolecular vibrations in contrast to infrared spectroscopy (IR), which observes intramolecular vibrations. Coherent detection enables direct calculations of both the imaginary and the real parts of the refractive index without using the Kramers-Kronig relations. Terahertz wave spectroscopy has been used to study the properties and absorption spectra characteristic of materials. In this paper, the spectral characteristics of cow skin, pig skin sheep skin, horse skin and deer skin have been measured with terahertz time-domain spectroscopy in the range of 0.1~2.0THz. The results show that THz-TDS technology provides an important tool for quality analysis and detection of leathers.

Thermal Characterization of Carbon Nanotubes by Photothermal Techniques

NASA Astrophysics Data System (ADS)

Leahu, G.; Li Voti, R.; Larciprete, M. C.; Sibilia, C.; Bertolotti, M.; Nefedov, I.; Anoshkin, I. V.

2015-06-01

Carbon nanotubes (CNTs) are multifunctional materials commonly used in a large number of applications in electronics, sensors, nanocomposites, thermal management, actuators, energy storage and conversion, and drug delivery. Despite recent important advances in the development of CNT purity assessment tools and atomic resolution imaging of individual nanotubes by scanning tunnelling microscopy and high-resolution transmission electron microscopy, the macroscale assessment of the overall surface qualities of commercial CNT materials remains a great challenge. The lack of quantitative measurement technology to characterize and compare the surface qualities of bulk manufactured and engineered CNT materials has negative impacts on the reliable and consistent nanomanufacturing of CNT products. In this paper it is shown how photoacoustic spectroscopy and photothermal radiometry represent useful non-destructive tools to study the optothermal properties of carbon nanotube thin films.

Defect States in Copper Indium Gallium Selenide Solar Cells from Two-Wavelength Excitation Photoluminescence Spectroscopy

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

Jensen, Soren A.; Dippo, Patricia; Mansfield, Lorelle M.

2016-11-21

We use two-wavelength excitation photoluminescence spectroscopy to probe defect states in CIGS thin films. Above-Eg excitation is combined with a tunable IR bias light that modulates the population of the defect states. We find that IR illumination in the range of 1400-2000 nm (0.62-0.89 eV) causes a reduction of the PL intensity, the magnitude of which scales linearly with IR power. Further, KF post deposition treatment has only a modest influence on the effect of the IR excitation. Initial data suggest that we have developed an optical characterization tool for band-gap defect states.

Noise spectroscopy as an equilibrium analysis tool for highly sensitive electrical biosensing

NASA Astrophysics Data System (ADS)

Guo, Qiushi; Kong, Tao; Su, Ruigong; Zhang, Qi; Cheng, Guosheng

2012-08-01

We demonstrate an approach for highly sensitive bio-detection based on silicon nanowire field-effect transistors by employing low frequency noise spectroscopy analysis. The inverse of noise amplitude of the device exhibits an enhanced gate coupling effect in strong inversion regime when measured in buffer solution than that in air. The approach was further validated by the detection of cardiac troponin I of 0.23 ng/ml in fetal bovine serum, in which 2 orders of change in noise amplitude was characterized. The selectivity of the proposed approach was also assessed by the addition of 10 μg/ml bovine serum albumin solution.

Characterization of biomaterials using FT-Raman spectroscopy

NASA Astrophysics Data System (ADS)

Söderholm, S.; Roos, Y. H.; Meinander, N.; Hotokka, M.

1998-06-01

Carbohydrates play an important role in the quality and preservation of pharmaceutical and food materials. The storage temperature and water content is very critical in storage and, therefore, it is very important to understand how the physical state of carbohydrates is affected by water. Carbohydrates in foods and pharmaceuticals are usually present in the amorphous form even if other substances present affect the physical properties of carbohydrates it is mainly temperature and water content that determine the physical state. Amorphous carbohydrates show a second order phase transition, the glass transition, that is critical for stability. When carbohydrates are stored above their glass transition temperature they loose stability. Crystallization above the glass transition temperature may result in loss of quality. Raman spectroscopy offers a useful tool in the characterization of phase transitions and effects of temperature and water content on material properties at a molecular level.

Raman spectroscopy as a tool for polyunsaturated compound characterization in gastropod and limnic terrestrial shell specimens

NASA Astrophysics Data System (ADS)

de Oliveira, Leandra N.; de Oliveira, Vanessa E.; D'ávila, Sthefane; Edwards, Howell G. M.; de Oliveira, Luiz Fernando C.

2013-10-01

The colours of mollusc shells were determined using the Raman spectroscopy and these analyses suggest that the conjugated polyenes (carotenoids) and psittacofulvins are the organic pigments incorporated into their skeletal structures responsible by their colorations. The symmetric stretching vibration of the carbonate ion gives rise to a very strong Raman band at ca. 1089 cm-1 and a weak band at 705 cm-1, for all samples; the second band characterizes the aragonite as the inorganic matrix and can be used as a marker. The specimens show bands at 1523-1500 and at 1130-1119 cm-1, assigned to the ν1 and ν2 modes of the polyenic chain vibrations, respectively. Another band at 1293 cm-1, assigned to the CHdbnd CH in-plane rocking mode of the olefinic hydrogen is also observed in all samples, which reinforces the psittacofulvin compound as the main pigment present in the analyzed samples.

Photoinduced force microscopy: A technique for hyperspectral nanochemical mapping

NASA Astrophysics Data System (ADS)

Murdick, Ryan A.; Morrison, William; Nowak, Derek; Albrecht, Thomas R.; Jahng, Junghoon; Park, Sung

2017-08-01

Advances in nanotechnology have intensified the need for tools that can characterize newly synthesized nanomaterials. A variety of techniques has recently been shown which combines atomic force microscopy (AFM) with optical illumination including tip-enhanced Raman spectroscopy (TERS), scattering-type scanning near-field optical microscopy (sSNOM), and photothermal induced resonance microscopy (PTIR). To varying degrees, these existing techniques enable optical spectroscopy with the nanoscale spatial resolution inherent to AFM, thereby providing nanochemical interrogation of a specimen. Here we discuss photoinduced force microscopy (PiFM), a recently developed technique for nanoscale optical spectroscopy that exploits image forces acting between an AFM tip and sample to detect wavelength-dependent polarization within the sample to generate absorption spectra. This approach enables ∼10 nm spatial resolution with spectra that show correlation with macroscopic optical absorption spectra. Unlike other techniques, PiFM achieves this high resolution with virtually no constraints on sample or substrate properties. The applicability of PiFM to a variety of archetypal systems is reported here, highlighting the potential of PiFM as a useful tool for a wide variety of industrial and academic investigations, including semiconducting nanoparticles, nanocellulose, block copolymers, and low dimensional systems, as well as chemical and morphological mixing at interfaces.

Electromagnetic field enhancement effects in group IV semiconductor nanowires. A Raman spectroscopy approach

NASA Astrophysics Data System (ADS)

Pura, J. L.; Anaya, J.; Souto, J.; Prieto, A. C.; Rodríguez, A.; Rodríguez, T.; Periwal, P.; Baron, T.; Jiménez, J.

2018-03-01

Semiconductor nanowires (NWs) are the building blocks of future nanoelectronic devices. Furthermore, their large refractive index and reduced dimension make them suitable for nanophotonics. The study of the interaction between nanowires and visible light reveals resonances that promise light absorption/scattering engineering for photonic applications. Micro-Raman spectroscopy has been used as a characterization tool for semiconductor nanowires. The light/nanowire interaction can be experimentally assessed through the micro-Raman spectra of individual nanowires. As compared to both metallic and dielectric nanowires, semiconductor nanowires add additional tools for photon engineering. In particular, one can grow heterostructured nanowires, both axial and radial, and also one could modulate the doping level and the surface condition among other factors than can affect the light/NW interaction. We present herein a study of the optical response of group IV semiconductor nanowires to visible photons. The study is experimentally carried out through micro-Raman spectroscopy of different group IV nanowires, both homogeneous and axially heterostructured (SiGe/Si). The results are analyzed in terms of the electromagnetic modelling of the light/nanowire interaction using finite element methods. The presence of axial heterostructures is shown to produce electromagnetic resonances promising new photon engineering capabilities of semiconductor nanowires.

Chairside CAD/CAM materials. Part 1: Measurement of elastic constants and microstructural characterization.

PubMed

Belli, Renan; Wendler, Michael; de Ligny, Dominique; Cicconi, Maria Rita; Petschelt, Anselm; Peterlik, Herwig; Lohbauer, Ulrich

2017-01-01

A deeper understanding of the mechanical behavior of dental restorative materials requires an insight into the materials elastic constants and microstructure. Here we aim to use complementary methodologies to thoroughly characterize chairside CAD/CAM materials and discuss the benefits and limitations of different analytical strategies. Eight commercial CAM/CAM materials, ranging from polycrystalline zirconia (e.max ZirCAD, Ivoclar-Vivadent), reinforced glasses (Vitablocs Mark II, VITA; Empress CAD, Ivoclar-Vivadent) and glass-ceramics (e.max CAD, Ivoclar-Vivadent; Suprinity, VITA; Celtra Duo, Dentsply) to hybrid materials (Enamic, VITA; Lava Ultimate, 3M ESPE) have been selected. Elastic constants were evaluated using three methods: Resonant Ultrasound Spectroscopy (RUS), Resonant Beam Technique (RBT) and Ultrasonic Pulse-Echo (PE). The microstructures were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Raman Spectroscopy and X-ray Diffraction (XRD). Young's modulus (E), Shear modulus (G), Bulk modulus (B) and Poisson's ratio (ν) were obtained for each material. E and ν reached values ranging from 10.9 (Lava Ultimate) to 201.4 (e.max ZirCAD) and 0.173 (Empress CAD) to 0.47 (Lava Ultimate), respectively. RUS showed to be the most complex and reliable method, while the PE method the easiest to perform but most unreliable. All dynamic methods have shown limitations in measuring the elastic constants of materials showing high damping behavior (hybrid materials). SEM images, Raman spectra and XRD patterns were made available for each material, showing to be complementary tools in the characterization of their crystal phases. Here different methodologies are compared for the measurement of elastic constants and microstructural characterization of CAD/CAM restorative materials. The elastic properties and crystal phases of eight materials are herein fully characterized. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Magnetic resonance metabolomics of intact tissue: a biotechnological tool in cancer diagnostics and treatment evaluation.

PubMed

Bathen, Tone F; Sitter, Beathe; Sjøbakk, Torill E; Tessem, May-Britt; Gribbestad, Ingrid S

2010-09-01

Personalized medicine is increasingly important in cancer treatment for its role in staging and its potential to improve stratification of patients. Different types of molecules, genes, proteins, and metabolites are being extensively explored as potential biomarkers. This review discusses the major findings and potential of tissue metabolites determined by high-resolution magic angle spinning magnetic resonance spectroscopy for cancer detection, characterization, and treatment monitoring.

Super-resolved FT-IR spectroscopy: Strategies, challenges, and opportunities for membrane biophysics.

PubMed

Li, Jessica J; Yip, Christopher M

2013-10-01

Direct correlation of molecular conformation with local structure is critical to studies of protein- and peptide-membrane interactions, particularly in the context of membrane-facilitated aggregation, and disruption or disordering. Infrared spectroscopy has long been a mainstay for determining molecular conformation, following folding dynamics, and characterizing reactions. While tremendous advances have been made in improving the spectral and temporal resolution of infrared spectroscopy, it has only been with the introduction of scanned-probe techniques that exploit the raster-scanning tip as either a source, scattering tool, or measurement probe that researchers have been able to obtain sub-diffraction limit IR spectra. This review will examine the history of correlated scanned-probe IR spectroscopies, from their inception to their use in studies of molecular aggregates, membrane domains, and cellular structures. The challenges and opportunities that these platforms present for examining dynamic phenomena will be discussed. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies. Copyright © 2013 Elsevier B.V. All rights reserved.

Parasites under the Spotlight: Applications of Vibrational Spectroscopy to Malaria Research.

PubMed

Perez-Guaita, David; Marzec, Katarzyna M; Hudson, Andrew; Evans, Corey; Chernenko, Tatyana; Matthäus, Christian; Miljkovic, Milos; Diem, Max; Heraud, Philip; Richards, Jack S; Andrew, Dean; Anderson, David A; Doerig, Christian; Garcia-Bustos, Jose; McNaughton, Don; Wood, Bayden R

2018-04-20

New technologies to diagnose malaria at high sensitivity and specificity are urgently needed in the developing world where the disease continues to pose a huge burden on society. Infrared and Raman spectroscopy-based diagnostic methods have a number of advantages compared with other diagnostic tests currently on the market. These include high sensitivity and specificity for detecting low levels of parasitemia along with ease of use and portability. Here, we review the application of vibrational spectroscopic techniques for monitoring and detecting malaria infection. We discuss the role of vibrational (infrared and Raman) spectroscopy in understanding the processes of parasite biology and its application to the study of interactions with antimalarial drugs. The distinct molecular phenotype that characterizes malaria infection and the high sensitivity enabling detection of low parasite densities provides a genuine opportunity for vibrational spectroscopy to become a front-line tool in the elimination of this deadly disease and provide molecular insights into the chemistry of this unique organism.

New PLS analysis approach to wine volatile compounds characterization by near infrared spectroscopy (NIR).

PubMed

Genisheva, Z; Quintelas, C; Mesquita, D P; Ferreira, E C; Oliveira, J M; Amaral, A L

2018-04-25

This work aims to explore the potential of near infrared (NIR) spectroscopy to quantify volatile compounds in Vinho Verde wines, commonly determined by gas chromatography. For this purpose, 105 Vinho Verde wine samples were analyzed using Fourier transform near infrared (FT-NIR) transmission spectroscopy in the range of 5435 cm -1 to 6357 cm -1 . Boxplot and principal components analysis (PCA) were performed for clusters identification and outliers removal. A partial least square (PLS) regression was then applied to develop the calibration models, by a new iterative approach. The predictive ability of the models was confirmed by an external validation procedure with an independent sample set. The obtained results could be considered as quite good with coefficients of determination (R 2 ) varying from 0.94 to 0.97. The current methodology, using NIR spectroscopy and chemometrics, can be seen as a promising rapid tool to determine volatile compounds in Vinho Verde wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

PubMed Central

2016-01-01

Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue ‘Raman spectroscopy in art and archaeology’. PMID:27799434

Vibrational spectroscopy

Treesearch

Umesh P. Agarwal; Rajai Atalla

2010-01-01

Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...

Early Detection of Cervical Intraepitelial Neoplasia in a Heterogeneos Group of Colombian Women Using Electrical Impedance Spectroscopy and the Miranda-López Algorithm

NASA Astrophysics Data System (ADS)

Miranda, David A.; Corzo, Sandra P.; González-Correa, Carlos-A.

2012-12-01

Electrical Impedance Spectroscopy (EIS) allows the study of the electrical properties of materials and structures such as biological tissues. EIS can be used as a diagnostic tool for the identification of pathological conditions such as cervical cancer. We used EIS in combination with genetic algorithms to characterize cervical epithelial squamous tissue in a heterogeneous sample of 56 Colombian women. All volunteers had a cytology taken for Papanicolau test and biopsy taken for histopathological analysis from those with a positive result (9 subjects). ROC analysis of the results suggest a sensitivity and specificity in the order of 0.73 and 0.86, respectively.

1H NMR study of inclusion compounds of phenylurea derivatives in β-cyclodextrin

NASA Astrophysics Data System (ADS)

Dupuy, N.; Barbry, D.; Bria, M.; Marquis, S.; Vrielynck, L.; Kister, J.

2005-04-01

Proton nuclear magnetic resonance spectroscopy ( 1H NMR), which has become an important tool for the study "in situ" of β-cyclodextrin (β-CD) complexes, was used to study and structurally characterize the inclusion complexes formed between β-CD and isoproturon, fenuron, monuron and diuron. The high variation of the chemical shifts from the proton located inside the cavity (H-3, H-5 and H-6) coupled with the non variation of the one located outer sphere of the β-CD (H-1, H-2 and H-4) provided clear evidence of the inclusion phenomena. Two-dimensional rotating frame Overhauser effect spectroscopy (ROESY) experiments were carried out to further support the proposed inclusion mode.

Probing surface hydrogen bonding and dynamics by natural abundance, multidimensional, 17O DNP-NMR spectroscopy

DOE PAGES

Perras, Frederic A.; Chaudhary, Umesh; Slowing, Igor I.; ...

2016-05-06

Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR spectroscopy of materials has, however, been limited to studying relatively receptive nuclei, and the particularly rare 17O nuclide, which is of great interest for materials science, has not been utilized. We demonstrate that advanced 17O SSNMR experiments can be performed on surface species at natural isotopic abundance using DNP. We use 17O DNP surface-enhanced 2D SSNMR to measure 17O{ 1H} HETCOR spectra as well as dipolar oscillations on a series of thermally treatedmore » mesoporous silica nanoparticle samples having different pore diameters. These experiments allow for a nonintrusive and unambiguous characterization of hydrogen bonding and dynamics at the surface of the material; no other single experiment can give such details about the interactions at the surface. Lastly, our data show that, upon drying, strongly hydrogen-bonded surface silanols, whose motions are greatly restricted by the interaction when compared to lone silanols, are selectively dehydroxylated.« less

UV irradiation study of a tripeptide isolated in an argon matrix: A tautomerism process evidenced by infrared and X-ray photoemission spectroscopies

NASA Astrophysics Data System (ADS)

Mateo-Marti, E.; Pradier, C. M.

2013-05-01

Matrix isolation is a powerful tool for studying photochemical processes occurring in isolated molecules. In this way, we characterized the chemical modifications occurring within a tri peptide molecule, IGF, when exposed to the influence of Ultraviolet (UV) irradiation. This paper first describes the successful formation of the tripeptide (IGF) argon matrix under vacuum conditions, followed by the in situ UV irradiation and characterization of the molecular matrix reactivity after UV-irradiation. These studies have been performed by combining two complementary spectroscopic techniques, Fourier-Transform Reflexion Absorption Spectroscopy (FT-IRRAS) and X-ray Photoelectron Spectroscopy (XPS). The IR spectra of the isolated peptide-matrix, before and after UV irradiation, revealed significant differences that could be associated either to a partial deprotonation of the molecule or to a tautomeric conversion of some amide bonds to imide ones on some peptide molecules. XPS analyses undoubtedly confirmed the second hypothesis; the combination of IRRAS and XPS results provide evidence that UV irradiation of peptides induces a chemical reaction, namely a shift of the double bond, meaning partial conversion from amide tautomer into an imidic acid tautomer.

Non-Gated Laser Induced Breakdown Spectroscopy Provides a Powerful Segmentation Tool on Concomitant Treatment of Characteristic and Continuum Emission

PubMed Central

Dasari, Ramachandra Rao; Barman, Ishan; Gundawar, Manoj Kumar

2014-01-01

We demonstrate the application of non-gated laser induced breakdown spectroscopy (LIBS) for characterization and classification of organic materials with similar chemical composition. While use of such a system introduces substantive continuum background in the spectral dataset, we show that appropriate treatment of the continuum and characteristic emission results in accurate discrimination of pharmaceutical formulations of similar stoichiometry. Specifically, our results suggest that near-perfect classification can be obtained by employing suitable multivariate analysis on the acquired spectra, without prior removal of the continuum background. Indeed, we conjecture that pre-processing in the form of background removal may introduce spurious features in the signal. Our findings in this report significantly advance the prior results in time-integrated LIBS application and suggest the possibility of a portable, non-gated LIBS system as a process analytical tool, given its simple instrumentation needs, real-time capability and lack of sample preparation requirements. PMID:25084522

Fluorescence Spectroscopy as a Tool for the Assessment of Liver Samples with Several Stages of Fibrosis.

PubMed

Fabila-Bustos, Diego A; Arroyo-Camarena, Úrsula D; López-Vancell, María D; Durán-Padilla, Marco A; Azuceno-García, Itzel; Stolik-Isakina, Suren; Valor-Reed, Alma; Ibarra-Coronado, Elizabeth; Hernández-Quintanar, Luis F; Escobedo, Galileo; de la Rosa-Vázquez, José M

2018-03-01

During the last years, fluorescence spectroscopy has been used as a potential tool for the evaluation and characterization of tissues with different disease conditions due to its low cost, high sensitivity, and minimally or noninvasive character. In this study, fluorescence spectroscopy was used to study 19 paraffin blocks containing human liver tissue from biopsies. All samples were previously analyzed by two senior pathologists in a single-blind trial. After their evaluation, four liver samples were classified as nonfibrosis (F0), four as initial fibrosis (F1-F2), four as advanced fibrosis (F3), and six as cirrhosis (F4). The fluorescence was induced at different wavelengths as follows: 330, 365, and 405 nm using a portable fiber-optic system. The fluorescence spectra were recorded in the range of 400-750 nm. A distinctive correlation between the shape of each spectrum and the level of fibrosis in the liver sample was detected. A multi-variate statistical analysis based on principal component analysis followed by linear discrimination analysis was applied to develop algorithms able to distinguish different stages of fibrosis based on the characteristics of fluorescence spectra. Pairwise comparisons were performed: F0 versus F1-F2, F1-F2 versus F3, F3 versus F4, and F1-F2 versus F4. The algorithms applied to each set of data yielded values of sensitivity and specificity that were higher than 90% and 95%, respectively, in all the analyzed cases. With this study, it is concluded that fluorescence spectroscopy can be used as a complementary tool for the assessment of liver fibrosis in liver tissue samples, which sets the stage for subsequent clinical trials.

Characterization of Rhenium Oxides Using ESCA

NASA Technical Reports Server (NTRS)

Panda, Binayak; Gentz, Steven J. (Technical Monitor)

2001-01-01

High melting point and inherent ductility (toughness) over a wide range of temperature has made Rhenium an engineering material of choice for several thrust chambers in propulsion systems. Although the material remains tough at high temperatures, it still can readily transform to several oxides. As many as eight different oxides have been reported in literature. When characterized using ESCA (Electron Spectroscopy for Chemical Analyses) these oxides show large shifts in the Re 4f line positions. While this unique property could be used as a tool for oxide characterization, literature indicates that only a few of these oxides have been characterized. Current work focuses on characterizing oxides of Rhenium using ESCA. Spectral line Re 4f have been measured for various oxides and the results have been compared with the Re 4f line positions of real-time oxidation products from space hardware.

Reconstructing Folding Energy Landscapes by Single-Molecule Force Spectroscopy

PubMed Central

Woodside, Michael T.; Block, Steven M.

2015-01-01

Folding may be described conceptually in terms of trajectories over a landscape of free energies corresponding to different molecular configurations. In practice, energy landscapes can be difficult to measure. Single-molecule force spectroscopy (SMFS), whereby structural changes are monitored in molecules subjected to controlled forces, has emerged as a powerful tool for probing energy landscapes. We summarize methods for reconstructing landscapes from force spectroscopy measurements under both equilibrium and nonequilibrium conditions. Other complementary, but technically less demanding, methods provide a model-dependent characterization of key features of the landscape. Once reconstructed, energy landscapes can be used to study critical folding parameters, such as the characteristic transition times required for structural changes and the effective diffusion coefficient setting the timescale for motions over the landscape. We also discuss issues that complicate measurement and interpretation, including the possibility of multiple states or pathways and the effects of projecting multiple dimensions onto a single coordinate. PMID:24895850

Detectors for single-molecule fluorescence imaging and spectroscopy

PubMed Central

MICHALET, X.; SIEGMUND, O.H.W.; VALLERGA, J.V.; JELINSKY, P.; MILLAUD, J.E.; WEISS, S.

2010-01-01

Single-molecule observation, characterization and manipulation techniques have recently come to the forefront of several research domains spanning chemistry, biology and physics. Due to the exquisite sensitivity, specificity, and unmasking of ensemble averaging, single-molecule fluorescence imaging and spectroscopy have become, in a short period of time, important tools in cell biology, biochemistry and biophysics. These methods led to new ways of thinking about biological processes such as viral infection, receptor diffusion and oligomerization, cellular signaling, protein-protein or protein-nucleic acid interactions, and molecular machines. Such achievements require a combination of several factors to be met, among which detector sensitivity and bandwidth are crucial. We examine here the needed performance of photodetectors used in these types of experiments, the current state of the art for different categories of detectors, and actual and future developments of single-photon counting detectors for single-molecule imaging and spectroscopy. PMID:20157633

FTIR spectroscopy as a tool for nano-material characterization

NASA Astrophysics Data System (ADS)

Baudot, Charles; Tan, Cher Ming; Kong, Jeng Chien

2010-11-01

Covalently grafting functional molecules to carbon nanotubes (CNTs) is an important step to leverage the excellent properties of that nano-fiber in order to exploit its potential in improving the mechanical and thermal properties of a composite material. While Fourier Transform Infra Red (FTIR) spectroscopy can display the various chemical bonding in a material, we found that the existing database in FTIR library does not cover all the bonding information present in functionalized CNTs because the bond between the grafted molecule and the CNT is new in the FTIR study. In order to extend the applicability of FTIR to nano-material, we present a theoretical method to derive FTIR spectroscopy and compare it with our experimental results. In particular, we illustrate a method for the identification of functional molecules grafted on CNTs, and we are able to confirm that the functional molecules are indeed covalently grafted on the CNTs without any alterations to its functional groups.

Multi-wavelength Raman spectroscopy study of supported vanadia catalysts: Structure identification and quantification

DOE PAGES

Wu, Zili

2014-10-20

Revealing the structure of supported metal oxide catalysts is a prerequisite for establishing the structure - catalysis relationship. Among a variety of characterization techniques, multi-wavelength Raman spectroscopy, combining resonance Raman and non-resonance Raman with different excitation wavelengths, has recently emerged as a particularly powerful tool in not only identifying but also quantifying the structure of supported metal oxide clusters. In our review, we make use of two supported vanadia systems, VO x/SiO 2 and VO x/CeO 2, as examples to showcase how one can employ this technique to investigate the heterogeneous structure of active oxide clusters and to understand themore » complex interaction between the oxide clusters and the support. Moreover, the qualitative and quantitative structural information gained from the multi-wavelength Raman spectroscopy can be utilized to provide fundamental insights for designing more efficient supported metal oxide catalysts.« less

Anharmonic Vibrational Spectroscopy on Metal Transition Complexes

NASA Astrophysics Data System (ADS)

Latouche, Camille; Bloino, Julien; Barone, Vincenzo

2014-06-01

Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic interpretation of experimental data and the full characterization of complex molecules can then be facilitated. Focusing on vibrational spectroscopy, several approaches have been proposed to simulate spectra beyond the double harmonic approximation, so that more details become available. However, a routine use of such tools requires the preliminary definition of a valid protocol with the most appropriate combination of electronic structure and nuclear calculation models. Several benchmark of anharmonic calculations frequency have been realized on organic molecules. Nevertheless, benchmarks of organometallics or inorganic metal complexes at this level are strongly lacking despite the interest of these systems due to their strong emission and vibrational properties. Herein we report the benchmark study realized with anharmonic calculations on simple metal complexes, along with some pilot applications on systems of direct technological or biological interest.

Discrimination of inflammatory bowel disease using Raman spectroscopy and linear discriminant analysis methods

NASA Astrophysics Data System (ADS)

Ding, Hao; Cao, Ming; DuPont, Andrew W.; Scott, Larry D.; Guha, Sushovan; Singhal, Shashideep; Younes, Mamoun; Pence, Isaac; Herline, Alan; Schwartz, David; Xu, Hua; Mahadevan-Jansen, Anita; Bi, Xiaohong

2016-03-01

Inflammatory bowel disease (IBD) is an idiopathic disease that is typically characterized by chronic inflammation of the gastrointestinal tract. Recently much effort has been devoted to the development of novel diagnostic tools that can assist physicians for fast, accurate, and automated diagnosis of the disease. Previous research based on Raman spectroscopy has shown promising results in differentiating IBD patients from normal screening cases. In the current study, we examined IBD patients in vivo through a colonoscope-coupled Raman system. Optical diagnosis for IBD discrimination was conducted based on full-range spectra using multivariate statistical methods. Further, we incorporated several feature selection methods in machine learning into the classification model. The diagnostic performance for disease differentiation was significantly improved after feature selection. Our results showed that improved IBD diagnosis can be achieved using Raman spectroscopy in combination with multivariate analysis and feature selection.

Application of Raman spectroscopy technology to studying Sudan I

NASA Astrophysics Data System (ADS)

Li, Gang; Zhang, Guoping; Chen, Chen

2006-06-01

Being an industrial dye, the Sudan I may have a toxic effect after oral intake on the body, and has recently been shown to cause cancer in rats, mice and rabbits. Because China and some other countries have detected the Sudan I in samples of the hot chilli powder and the chilli products, it is necessary to study the characteristics of this dye. As one kind of molecule scattering spectroscopy, Raman spectroscopy is characterized by the frequency excursion caused by interactions of molecules and photons. The frequency excursion reflects the margin between certain two vibrational or rotational energy states, and shows the information of the molecule. Because Raman spectroscopy can provides quick, easy, reproducible, and non-destructive analysis, both qualitative and quantitative, with no sample preparation required, Raman spectroscopy has been a particularly promising technique for analyzing the characteristics and structures of molecules, especially organic ones. Now, it has a broad application in biological, chemical, environmental and industrial applications. This paper firstly introduces Sudan I dye and the Raman spectroscopy technology, and then describes its application to the Sudan I. Secondly, the fingerprint spectra of the Sudan I are respectively assigned and analyzed in detail. Finally, the conclusion that the Raman spectroscopy technology is a powerful tool to determine the Sudan I is drawn.

The development of "fab-chips" as low-cost, sensitive surface-enhanced Raman spectroscopy (SERS) substrates for analytical applications.

PubMed

Robinson, Ashley M; Zhao, Lili; Shah Alam, Marwa Y; Bhandari, Paridhi; Harroun, Scott G; Dendukuri, Dhananjaya; Blackburn, Jonathan; Brosseau, Christa L

2015-02-07

The demand for methods and technologies capable of rapid, inexpensive and continuous monitoring of health status or exposure to environmental pollutants persists. In this work, the development of novel surface-enhanced Raman spectroscopy (SERS) substrates from metal-coated silk fabric, known as zari, presents the potential for SERS substrates to be incorporated into clothing and other textiles for the routine monitoring of important analytes, such as disease biomarkers or environmental pollutants. Characterization of the zari fabric was completed using scanning electron microscopy, energy dispersive X-ray analysis and Raman spectroscopy. Silver nanoparticles (AgNPs) were prepared, characterized by transmission electron microscopy and UV-vis spectroscopy, and used to treat fabric samples by incubation, drop-coating and in situ synthesis. The quality of the treated fabric was evaluated by collecting the SERS signal of 4,4'-bipyridine on these substrates. When AgNPs were drop-coated on the fabric, sensitive and reproducible substrates were obtained. Adenine was selected as a second probe molecule, because it dominates the SERS signal of DNA, which is an important class of disease biomarker, particularly for pathogens such as Plasmodium spp. and Mycobacterium tuberculosis. Excellent signal enhancement could be achieved on these affordable substrates, suggesting that the developed fabric chips have the potential for expanding the use of SERS as a diagnostic and environmental monitoring tool for application in wearable sensor technologies.

VIS-NIR spectroscopy as a process analytical technology for compositional characterization of film biopolymers and correlation with their mechanical properties.

PubMed

Barbin, Douglas Fernandes; Valous, Nektarios A; Dias, Adriana Passos; Camisa, Jaqueline; Hirooka, Elisa Yoko; Yamashita, Fabio

2015-11-01

There is an increasing interest in the use of polysaccharides and proteins for the production of biodegradable films. Visible and near-infrared (VIS-NIR) spectroscopy is a reliable analytical tool for objective analyses of biological sample attributes. The objective is to investigate the potential of VIS-NIR spectroscopy as a process analytical technology for compositional characterization of biodegradable materials and correlation to their mechanical properties. Biofilms were produced by single-screw extrusion with different combinations of polybutylene adipate-co-terephthalate, whole oat flour, glycerol, magnesium stearate, and citric acid. Spectral data were recorded in the range of 400-2498nm at 2nm intervals. Partial least square regression was used to investigate the correlation between spectral information and mechanical properties. Results show that spectral information is influenced by the major constituent components, as they are clustered according to polybutylene adipate-co-terephthalate content. Results for regression models using the spectral information as predictor of tensile properties achieved satisfactory results, with coefficients of prediction (R(2)C) of 0.83, 0.88 and 0.92 (calibration models) for elongation, tensile strength, and Young's modulus, respectively. Results corroborate the correlation of NIR spectra with tensile properties, showing that NIR spectroscopy has potential as a rapid analytical technology for non-destructive assessment of the mechanical properties of the films. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of far-infrared spectroscopy to the structural identification of protein materials.

PubMed

Han, Yanchen; Ling, Shengjie; Qi, Zeming; Shao, Zhengzhong; Chen, Xin

2018-05-03

Although far-infrared (IR) spectroscopy has been shown to be a powerful tool to determine peptide structure and to detect structural transitions in peptides, it has been overlooked in the characterization of proteins. Herein, we used far-IR spectroscopy to monitor the structure of four abundant non-bioactive proteins, namely, soybean protein isolate (SPI), pea protein isolate (PPI) and two types of silk fibroins (SFs), domestic Bombyx mori and wild Antheraea pernyi. The two globular proteins SPI and PPI result in broad and weak far-IR bands (between 50 and 700 cm-1), in agreement with those of some other bioactive globular proteins previously studied (lysozyme, myoglobin, hemoglobin, etc.) that generally only have random amino acid sequences. Interestingly, the two SFs, which are characterized by a structure composed of highly repetitive motifs, show several sharp far-IR characteristic absorption peaks. Moreover, some of these characteristic peaks (such as the peaks at 260 and 428 cm-1 in B. mori, and the peaks at 245 and 448 cm-1 in A. pernyi) are sensitive to conformational changes; hence, they can be directly used to monitor conformational transitions in SFs. Furthermore, since SF absorption bands clearly differ from those of globular proteins and different SFs even show distinct adsorption bands, far-IR spectroscopy can be applied to distinguish and determine the specific SF component within protein blends.

The use of one- and two- photon induced fluorescence spectroscopy for the optical characterization of carcinogenic aflatoxins

NASA Astrophysics Data System (ADS)

Smeesters, L.; Meulebroeck, W.; Raeymaekers, S.; Thienpont, H.

2014-09-01

Carcinogenic and toxic contaminants in food and feed products are nowadays mostly detected by destructive, time-consuming chemical analyses, like HPLC and LC-MS/MS methods. However, as a consequence of the severe and growing regulations on food products by the European Union, there arose an increased demand for the ultra-fast, high-sensitive and non-destructive detection of contaminants in food and feed products. Therefore, we have investigated fluorescence spectroscopy for the characterization of carcinogenic aflatoxins. With the use of a tunable titanium-sapphire laser in combination with second and third harmonic wavelength generation, both one- and two-photon induced fluorescence excitation wavelengths could be generated using the same setup. We characterized and compared the one- and two-photon induced fluorescence spectra of pure aflatoxin powder, after excitation with 365nm and 730nm respectively. Moreover, we investigated the absolute fluorescence intensity as function of the excitation power density. Afterwards, we applied our characterization setup to the detection of aflatoxins in maize grains. The fluorescence spectra of both healthy and contaminated maize samples were experimentally characterized. In addition to the fluorescence spectrum of the pure aflatoxin, we observed an unwanted influence of the intrinsic fluorescence of the maize. Depending on the excitation wavelength, a varying contrast between the fluorescence spectra of the healthy and contaminated samples was obtained. After a comparison of the measured fluorescence signals, a detection criterion for the optical identification of the contaminated maize samples could be defined. As a result, this illustrates the use of fluorescence spectroscopy as a valuable tool for the non-destructive, real-time and high-sensitive detection of aflatoxins in maize.

Ultrafast structural molecular dynamics investigated with 2D infrared spectroscopy methods.

PubMed

Kraack, Jan Philip

2017-10-25

Ultrafast, multi-dimensional infrared (IR) spectroscopy has been advanced in recent years to a versatile analytical tool with a broad range of applications to elucidate molecular structure on ultrafast timescales, and it can be used for samples in a many different environments. Following a short and general introduction on the benefits of 2D IR spectroscopy, the first part of this chapter contains a brief discussion on basic descriptions and conceptual considerations of 2D IR spectroscopy. Outstanding classical applications of 2D IR are used afterwards to highlight the strengths and basic applicability of the method. This includes the identification of vibrational coupling in molecules, characterization of spectral diffusion dynamics, chemical exchange of chemical bond formation and breaking, as well as dynamics of intra- and intermolecular energy transfer for molecules in bulk solution and thin films. In the second part, several important, recently developed variants and new applications of 2D IR spectroscopy are introduced. These methods focus on (i) applications to molecules under two- and three-dimensional confinement, (ii) the combination of 2D IR with electrochemistry, (iii) ultrafast 2D IR in conjunction with diffraction-limited microscopy, (iv) several variants of non-equilibrium 2D IR spectroscopy such as transient 2D IR and 3D IR, and (v) extensions of the pump and probe spectral regions for multi-dimensional vibrational spectroscopy towards mixed vibrational-electronic spectroscopies. In light of these examples, the important open scientific and conceptual questions with regard to intra- and intermolecular dynamics are highlighted. Such questions can be tackled with the existing arsenal of experimental variants of 2D IR spectroscopy to promote the understanding of fundamentally new aspects in chemistry, biology and materials science. The final part of the chapter introduces several concepts of currently performed technical developments, which aim at exploiting 2D IR spectroscopy as an analytical tool. Such developments embrace the combination of 2D IR spectroscopy and plasmonic spectroscopy for ultrasensitive analytics, merging 2D IR spectroscopy with ultra-high-resolution microscopy (nanoscopy), future variants of transient 2D IR methods, or 2D IR in conjunction with microfluidics. It is expected that these techniques will allow for groundbreaking research in many new areas of natural sciences.

Preparation and Characterization of PETI-330/Multiwalled Carbon Nanotube Composites

NASA Technical Reports Server (NTRS)

Ghose, Sayata; Watson, Kent A.; Working, Dennis C.; Delozier, Donavon M.; Criss, Jim M.; Siochi, Emilie J.; Connell, John W.

2005-01-01

As part of an ongoing effort to incorporate multi-functionality into advanced composites, blends of PETI-330 and multi-walled carbon nanotubes (MWCNTs) were prepared, characterized and fabricated into moldings. The PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight percent by dry mixing the components in a ball mill. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, PETI-330/MWCNT samples were scaled up to approx. 300 g and used to fabricate moldings 10.2 cm x 15.2 cm x 0.32 cm thick. The moldings were fabricated by injecting the mixtures at 260-280 C into a stainless steel tool followed by curing for 1 h at 371 C. The tool was designed to impart high shear during the injection process in an attempt to achieve some alignment of the MWCNTs in the flow direction. Good quality moldings were obtained that were subsequently characterized for thermal, mechanical and electrical properties. The degree of dispersion and alignment of the MWCNTs were investigated using high-resolution scanning electron microscopy and Raman spectroscopy. The preparation and preliminary characterization of PETI-330/MWCNT composites will be discussed. Keywords: phenylethynyl terminated imides, high temperature polymers, nanocomposites,

Dynamic tissue analysis using time- and wavelength-resolved fluorescence spectroscopy for atherosclerosis diagnosis

PubMed Central

Sun, Yinghua; Sun, Yang; Stephens, Douglas; Xie, Hongtao; Phipps, Jennifer; Saroufeem, Ramez; Southard, Jeffrey; Elson, Daniel S.; Marcu, Laura

2011-01-01

Simultaneous time- and wavelength-resolved fluorescence spectroscopy (STWRFS) was developed and tested for the dynamic characterization of atherosclerotic tissue ex vivo and arterial vessels in vivo. Autofluorescence, induced by a 337 nm, 700 ps pulsed laser, was split to three wavelength sub-bands using dichroic filters, with each sub-band coupled into a different length of optical fiber for temporal separation. STWRFS allows for fast recording/analysis (few microseconds) of time-resolved fluorescence emission in these sub-bands and rapid scanning. Distinct compositions of excised human atherosclerotic aorta were clearly discriminated over scanning lengths of several centimeters based on fluorescence lifetime and the intensity ratio between 390 and 452 nm. Operation of STWRFS blood flow was further validated in pig femoral arteries in vivo using a single-fiber probe integrated with an ultrasound imaging catheter. Current results demonstrate the potential of STWRFS as a tool for real-time optical characterization of arterial tissue composition and for atherosclerosis research and diagnosis. PMID:21369214

Characterization of extracellular polymeric substances in the biofilms of typical bacteria by the sulfur K-edge XANES spectroscopy.

PubMed

Lin, Huirong; Ye, Chengsong; Lv, Lu; Zheng, Clark Renjun; Zhang, Shenghua; Zheng, Lei; Zhao, Yidong; Yu, Xin

2014-08-01

A combined approach of physicochemical extraction and sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to characterize the extracellular polymeric substances (EPS) of typical bacterial biofilms in this study. Physicochemical analysis showed variation of the contents of DNA, polysaccharide and protein in different fractions of EPS in different mediums. The sulfur K-edge XANES analysis yielded a variety of spectra. Spectral fitting of the XANES spectra utilizing a large set of model compounds showed that there was more reduced sulfur in both LB-EPS (loosely bound EPS) and TB-EPS (tightly bound EPS) of all the biofilms in LB medium than in R2A medium. More oxidized sulfur was identified in LB-EPS than that in TB-EPS, suggesting different niches and physiological heterogeneity in the biofilms. Our results suggested that the sulfur K-edge XANES can be a useful tool to analyze the sulfur speciation in EPS of biofilms. Copyright © 2014. Published by Elsevier B.V.

Physicochemical Characterization of Functional Lignin–Silica Hybrid Fillers for Potential Application in Abrasive Tools

PubMed Central

Strzemiecka, Beata; Klapiszewski, Łukasz; Jamrozik, Artur; Szalaty, Tadeusz J.; Matykiewicz, Danuta; Sterzyński, Tomasz; Voelkel, Adam; Jesionowski, Teofil

2016-01-01

Functional lignin–SiO2 hybrid fillers were prepared for potential application in binders for phenolic resins, and their chemical structure was characterized. The properties of these fillers and of composites obtained from them with phenolic resin were compared with those of systems with lignin or silica alone. The chemical structure of the materials was investigated by Fourier transform infrared spectroscopy (FT-IR) and carbon-13 nuclear magnetic resonance spectroscopy (13C CP MAS NMR). The thermal stability of the new functional fillers was examined by thermogravimetric analysis–mass spectrometry (TG-MS). Thermo-mechanical properties of the lignin–silica hybrids and resin systems were investigated by dynamic mechanical thermal analysis (DMTA). The DMTA results showed that abrasive composites with lignin–SiO2 fillers have better thermo-mechanical properties than systems with silica alone. Thus, fillers based on lignin might provide new, promising properties for the abrasive industry, combining the good properties of lignin as a plasticizer and of silica as a filler improving mechanical properties. PMID:28773639

Emerging technologies for the non-invasive characterization of physical-mechanical properties of tablets.

PubMed

Dave, Vivek S; Shahin, Hend I; Youngren-Ortiz, Susanne R; Chougule, Mahavir B; Haware, Rahul V

2017-10-30

The density, porosity, breaking force, viscoelastic properties, and the presence or absence of any structural defects or irregularities are important physical-mechanical quality attributes of popular solid dosage forms like tablets. The irregularities associated with these attributes may influence the drug product functionality. Thus, an accurate and efficient characterization of these properties is critical for successful development and manufacturing of a robust tablets. These properties are mainly analyzed and monitored with traditional pharmacopeial and non-pharmacopeial methods. Such methods are associated with several challenges such as lack of spatial resolution, efficiency, or sample-sparing attributes. Recent advances in technology, design, instrumentation, and software have led to the emergence of newer techniques for non-invasive characterization of physical-mechanical properties of tablets. These techniques include near infrared spectroscopy, Raman spectroscopy, X-ray microtomography, nuclear magnetic resonance (NMR) imaging, terahertz pulsed imaging, laser-induced breakdown spectroscopy, and various acoustic- and thermal-based techniques. Such state-of-the-art techniques are currently applied at various stages of development and manufacturing of tablets at industrial scale. Each technique has specific advantages or challenges with respect to operational efficiency and cost, compared to traditional analytical methods. Currently, most of these techniques are used as secondary analytical tools to support the traditional methods in characterizing or monitoring tablet quality attributes. Therefore, further development in the instrumentation and software, and studies on the applications are necessary for their adoption in routine analysis and monitoring of tablet physical-mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Positronics of subnanometer atomistic imperfections in solids as a high-informative structure characterization tool.

PubMed

Shpotyuk, Oleh; Filipecki, Jacek; Ingram, Adam; Golovchak, Roman; Vakiv, Mykola; Klym, Halyna; Balitska, Valentyna; Shpotyuk, Mykhaylo; Kozdras, Andrzej

2015-01-01

Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize different types of nanomaterials treated within three-term fitting procedure are critically reconsidered. In contrast to conventional three-term analysis based on admixed positron- and positronium-trapping modes, the process of nanostructurization is considered as substitutional positron-positronium trapping within the same host matrix. Developed formalism allows estimate interfacial void volumes responsible for positron trapping and characteristic bulk positron lifetimes in nanoparticle-affected inhomogeneous media. This algorithm was well justified at the example of thermally induced nanostructurization occurring in 80GeSe2-20Ga2Se3 glass.

Characterizing extrasolar planets

NASA Astrophysics Data System (ADS)

Brown, Timothy M.

Transiting extrasolar planets provide the best current opportunities for characterizing the physical properties of extrasolar planets. In this review, I first describe the geometry of planetary transits, and methods for detecting and refining the observations of such transits. I derive the methods by which transit light curves and radial velocity data can be analyzed to yield estimates of the planetary radius, mass, and orbital parameters. I also show how visible-light and infrared spectroscopy can be valuable tools for understanding the composition, temperature, and dynamics of the atmospheres of transiting planets. Finally, I relate the outcome of a participatory lecture-hall exercise relating to one term in the Drake equation, namely the lifetime of technical civilizations.

Positronics of subnanometer atomistic imperfections in solids as a high-informative structure characterization tool

NASA Astrophysics Data System (ADS)

Shpotyuk, Oleh; Filipecki, Jacek; Ingram, Adam; Golovchak, Roman; Vakiv, Mykola; Klym, Halyna; Balitska, Valentyna; Shpotyuk, Mykhaylo; Kozdras, Andrzej

2015-02-01

Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize different types of nanomaterials treated within three-term fitting procedure are critically reconsidered. In contrast to conventional three-term analysis based on admixed positron- and positronium-trapping modes, the process of nanostructurization is considered as substitutional positron-positronium trapping within the same host matrix. Developed formalism allows estimate interfacial void volumes responsible for positron trapping and characteristic bulk positron lifetimes in nanoparticle-affected inhomogeneous media. This algorithm was well justified at the example of thermally induced nanostructurization occurring in 80GeSe2-20Ga2Se3 glass.

Infrared Spectroscopy as a Chemical Fingerprinting Tool

NASA Technical Reports Server (NTRS)

Huff, Timothy L.

2003-01-01

Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. Any sample material that will interact with infrared light produces a spectrum and, although normally associated with organic materials, inorganic compounds may also be infrared active. The technique is rapid, reproducible and usually non-invasive to the sample. That it is non-invasive allows for additional characterization of the original material using other analytical techniques including thermal analysis and RAMAN spectroscopic techniques. With the appropriate accessories, the technique can be used to examine samples in liquid, solid or gas phase. Both aqueous and non-aqueous free-flowing solutions can be analyzed, as can viscous liquids such as heavy oils and greases. Solid samples of varying sizes and shapes may also be examined and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be analyzed. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

Diagnostic tool for early detection of ovarian cancers using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Lieber, Chad A.; Molpus, Kelly; Brader, Kevin; Mahadevan-Jansen, Anita

2000-05-01

With an overall survival rate of about 35 percent, ovarian cancer claims more than 13,000 women in the US each year. It is estimated that roughly 1 in 70 women will develop ovarian cancer. Current screening techniques are challenged due to cost-effectiveness, variable false-positive results, and the asymptomatic nature of the early stages of ovarian cancer. The predominant screening method for ovarian cancers is transvaginal sonography (TVS). TVS is fairly accomplished at ovarian cancer detection, however it is inefficient in distinguishing between benign and malignant masses. Accurate diagnosis of the ovarian tumor relies on exploratory laparotomy, thus increasing the cost and hazard of false- positive screening methods. Raman spectroscopy has been sued successfully as a diagnostic tool in several organ systems in vitro. These studies have shown that Raman spectroscopy can be used to provide diagnosis of subtle changes in tissue pathology with high accuracy. Based on this success, we have developed a Raman spectroscopic system for application in the ovary. Using this system, the Raman signatures of normal and various types of non-normal human ovarian tissues were characterized in vitro. Raman spectra are being analyzed, and empirical as well as multivariate discriminatory algorithms developed. Based on the result of this study, a strategy for in vivo trials will be planned.

Probing the Sulfur-Modified Capping Layer of Gold Nanoparticles Using Surface Enhanced Raman Spectroscopy (SERS) Effects.

PubMed

Prado, Adilson R; Souza, Danilo Oliveira de; Oliveira, Jairo P; Pereira, Rayssa H A; Guimarães, Marco C C; Nogueira, Breno V; Dixini, Pedro V; Ribeiro, Moisés R N; Pontes, Maria J

2017-12-01

Gold nanoparticles (AuNP) exhibit particular plasmonic properties when stimulated by visible light, which makes them a promising tool to many applications in sensor technology and biomedical applications, especially when associated to sulfur-based compounds. Sulfur species form a great variety of self-assembled structures that cap AuNP and this interaction rules the optical and plasmonic properties of the system. Here, we report the behavior of citrate-stabilized gold nanospheres in two distinct sulfur colloidal solutions, namely, thiocyanate and sulfide ionic solutions. Citrate-capped gold nanospheres were characterized using ultraviolet-visible (UV-Vis) absorption, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and atomic force microscopy (AFM). In the presence of sulfur species, we have observed the formation of NP clusters and chain-like structures, giving rise to surface-enhanced effects. Surface-enhanced Raman spectroscopy (SERS) pointed to a modification in citrate vibrational modes, which suggests substitution of citrate by either thiocyanate or sulfide ions with distinct dynamics, as showed by in situ fluorescence. Moreover, we report the emergence of surface-enhanced infrared absorption (SEIRA) effect, which corroborates SERS conclusions. Further, SEIRA shows a great potential as a tool for specification of sulfur compounds in colloidal solutions, which is particularly useful when dealing with sensor technology.

Exploring actinide materials through synchrotron radiation techniques.

PubMed

Shi, Wei-Qun; Yuan, Li-Yong; Wang, Cong-Zhi; Wang, Lin; Mei, Lei; Xiao, Cheng-Liang; Zhang, Li; Li, Zi-Jie; Zhao, Yu-Liang; Chai, Zhi-Fang

2014-12-10

Synchrotron radiation (SR) based techniques have been utilized with increasing frequency in the past decade to explore the brilliant and challenging sciences of actinide-based materials. This trend is partially driven by the basic needs for multi-scale actinide speciation and bonding information and also the realistic needs for nuclear energy research. In this review, recent research progresses on actinide related materials by means of various SR techniques were selectively highlighted and summarized, with the emphasis on X-ray absorption spectroscopy, X-ray diffraction and scattering spectroscopy, which are powerful tools to characterize actinide materials. In addition, advanced SR techniques for exploring future advanced nuclear fuel cycles dealing with actinides are illustrated as well. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface-enhanced Raman scattering spectroscopy characterization and identification of foodborne bacteria

NASA Astrophysics Data System (ADS)

Liu, Yongliang; Chen, Yud-Ren; Nou, Xiangwu; Chao, Kaunglin

2007-09-01

Rapid and routine identification of foodborne bacteria are considerably important, because of bio- / agro- terrorism threats, public health concerns, and economic loss. Conventional, PCR, and immunoassay methods for the detection of bacteria are generally time-consuming, chemical reagent necessary and multi-step procedures. Fast microbial detection requires minimal sample preparation, permits the routine analysis of large numbers of samples with negligible reagent costs, and is easy to operate. Therefore, we have developed silver colloidal nanoparticle based surface-enhanced Raman scattering (SERS) spectroscopy as a potential tool for the rapid and routine detection of E. coli and L. monocytogenes. This study presents the further results of our examination on S. typhimonium, one of the most commonly outbreak bacteria, for the characteristic bands and subsequent identification.

Determination of carrier lifetime and mobility in colloidal quantum dot films via impedance spectroscopy

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

Rath, Arup K.; Lasanta, Tania; Bernechea, Maria

2014-02-10

Impedance Spectroscopy (IS) proves to be a powerful tool for the determination of carrier lifetime and majority carrier mobility in colloidal quantum dot films. We employ IS to determine the carrier lifetime in PbS quantum dot Schottky solar cells with Al and we verify the validity of the technique via transient photovoltage. We also present a simple approach based on an RC model that allows the determination of carrier mobility in PbS quantum dot films and we corroborate the results via comparison with space charge limited measurements. In summary, we demonstrate the potential of IS to characterize key-to-photovoltaics optoelectronic properties,more » carrier lifetime, and mobility, in a facile way.« less

A construction of standardized near infrared hyper-spectral teeth database: a first step in the development of reliable diagnostic tool for quantification and early detection of caries

NASA Astrophysics Data System (ADS)

Bürmen, Miran; Usenik, Peter; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

2011-03-01

Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentin and pulp. If left untreated, the disease can lead to pain, infection and tooth loss. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Several papers reported on near infrared (NIR) spectroscopy to be a potentially useful noninvasive spectroscopic technique for early detection of caries lesions. However, the conducted studies were mostly qualitative and did not include the critical assessment of the spectral variability of the sound and carious dental tissues and influence of the water content. Such assessment is essential for development and validation of reliable qualitative and especially quantitative diagnostic tools based on NIR spectroscopy. In order to characterize the described spectral variability, a standardized diffuse reflectance hyper-spectral database was constructed by imaging 12 extracted human teeth with natural lesions of various degrees in the spectral range from 900 to 1700 nm with spectral resolution of 10 nm. Additionally, all the teeth were imaged by digital color camera. The influence of water content on the acquired spectra was characterized by monitoring the teeth during the drying process. The images were assessed by an expert, thereby obtaining the gold standard. By analyzing the acquired spectra we were able to accurately model the spectral variability of the sound dental tissues and identify the advantages and limitations of NIR hyper-spectral imaging.

Neuronavigation using three-dimensional proton magnetic resonance spectroscopy data.

PubMed

Kanberoglu, Berkay; Moore, Nina Z; Frakes, David; Karam, Lina J; Debbins, Josef P; Preul, Mark C

2014-01-01

Applications in clinical medicine can benefit from fusion of spectroscopy data with anatomical imagery. For example, new 3-dimensional (3D) spectroscopy techniques allow for improved correlation of metabolite profiles with specific regions of interest in anatomical tumor images, which can be useful in characterizing and treating heterogeneous tumors that appear structurally homogeneous. We sought to develop a clinical workflow and uniquely capable custom software tool to integrate advanced 3-tesla 3D proton magnetic resonance spectroscopic imaging ((1)H-MRSI) into industry standard image-guided neuronavigation systems, especially for use in brain tumor surgery. (1)H-MRSI spectra from preoperative scanning on 15 patients with recurrent or newly diagnosed meningiomas were processed and analyzed, and specific voxels were selected based on their chemical contents. 3D neuronavigation overlays were then generated and applied to anatomical image data in the operating room. The proposed 3D methods fully account for scanner calibration and comprise tools that we have now made publicly available. The new methods were quantitatively validated through a phantom study and applied successfully to mitigate biopsy uncertainty in a clinical study of meningiomas. The proposed methods improve upon the current state of the art in neuronavigation through the use of detailed 3D (1)H-MRSI data. Specifically, 3D MRSI-based overlays provide comprehensive, quantitative visual cues and location information during neurosurgery, enabling a progressive new form of online spectroscopy-guided neuronavigation. © 2014 S. Karger AG, Basel.

XPS Protocol for the Characterization of Pristine and Functionalized Single Wall Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Sosa, E. D.; Allada, R.; Huffman, C. B.; Arepalli, S.

2009-01-01

Recent interest in developing new applications for carbon nanotubes (CNT) has fueled the need to use accurate macroscopic and nanoscopic techniques to characterize and understand their chemistry. X-ray photoelectron spectroscopy (XPS) has proved to be a useful analytical tool for nanoscale surface characterization of materials including carbon nanotubes. Recent nanotechnology research at NASA Johnson Space Center (NASA-JSC) helped to establish a characterization protocol for quality assessment for single wall carbon nanotubes (SWCNTs). Here, a review of some of the major factors of the XPS technique that can influence the quality of analytical data, suggestions for methods to maximize the quality of data obtained by XPS, and the development of a protocol for XPS characterization as a complementary technique for analyzing the purity and surface characteristics of SWCNTs is presented. The XPS protocol is then applied to a number of experiments including impurity analysis and the study of chemical modifications for SWCNTs.

Studies on the formation and stability of triplex DNA using fluorescence correlation spectroscopy.

PubMed

Hu, Hongyan; Huang, Xiangyi; Ren, Jicun

2016-05-01

Triplex DNA has become one of the most useful recognition motifs in the design of new molecular biology tools, therapeutic agents and sophisticated DNA-based nanomaterials because of its direct recognition of natural double-stranded DNA. In this paper, we developed a sensitive and microscale method to study the formation and stability characterization of triplex DNA using fluorescence correlation spectroscopy (FCS). The principle of this method is mainly based on the excellent capacity of FCS for sensitively distinguishing between free single-strand DNA (ssDNA) fluorescent probes and fluorescent probe-double-strand DNA (dsDNA) hybridized complexes. First, we systematically investigated the experimental conditions of triplex DNA formation. Then, we evaluated the equilibrium association constants (K(a)) under different ssDNA probe lengths, composition and pH. Finally, we used FCS to measure the hybridization fraction of a 20-mer perfectly matched ssDNA probe and three single-base mismatched ssDNA probes with 146-mer dsDNA. Our data illustrated that FCS is a useful tool for the direct determination of the thermodynamic parameters of triplex DNA formation and discrimination of a single-base mismatch of triplex DNA without denaturation. Compared with current methods, our method is characterized by high sensitivity, good universality and small sample and reagent requirements. More importantly, our method has the potential to become a platform for triplex DNA research in vitro. Copyright © 2015 John Wiley & Sons, Ltd.

Study of thermal pre-treatment on anaerobic digestion of slaughterhouse waste by TGA-MS and FTIR spectroscopy.

PubMed

Rodríguez-Abalde, Ángela; Gómez, Xiomar; Blanco, Daniel; Cuetos, María José; Fernández, Belén; Flotats, Xavier

2013-12-01

Thermogravimetric analysis coupled to mass spectrometry (TGA-MS) and Fourier-transform infrared spectroscopy (FTIR) were used to describe the effect of pasteurization as a hygienic pre-treatment of animal by-products over biogas production. Piggery and poultry meat wastes were used as substrates for assessing the anaerobic digestion under batch conditions at mesophilic range. Poultry waste was characterized by high protein and carbohydrate content, while piggery waste presented a major fraction of fat and lower carbohydrate content. Results from anaerobic digestion tests showed a lower methane yield for the pre-treated poultry sample. TGA-MS and FTIR spectroscopy allowed the qualitative identification of recalcitrant nitrogen-containing compounds in the pre-treated poultry sample, produced by Maillard reactions. In the case of piggery waste, the recalcitrant compounds were not detected and its biodegradability test reported higher methane yield and production rates. TGA-MS and FTIR spectroscopy were demonstrated to be useful tools for explaining results obtained by anaerobic biodegradability test and in describing the presence of inhibitory problems.

Structure and Order of Phosphonic Acid-Based Self-Assembled Monolayers on Si(100)

PubMed Central

Dubey, Manish; Weidner, Tobias; Gamble, Lara J.; Castner, David G.

2010-01-01

Organophosphonic acid self-assembled monolayers (SAMs) on oxide surfaces have recently seen increased use in electrical and biological sensor applications. The reliability and reproducibility of these sensors require good molecular organization in these SAMs. In this regard, packing, order and alignment in the SAMs is important, as it influences the electron transport measurements. In this study, we examine the order of hydroxyl- and methyl- terminated phosphonate films deposited onto silicon oxide surfaces by the tethering by aggregation and growth method using complementary, state-of-art surface characterization tools. Near edge x-ray absorption fine structure (NEXAFS) spectroscopy and in situ sum frequency generation (SFG) spectroscopy are used to study the order of the phosphonate SAMs in vacuum and under aqueous conditions, respectively. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry results show that these samples form chemically intact monolayer phosphonate films. NEXAFS and SFG spectroscopy showed that molecular order exists in the octadecylphosphonic acid and 11-hydroxyundecylphosphonic acid SAMs. The chain tilt angles in these SAMs were approximately 37° and 45°, respectively. PMID:20735054

Distinct charge dynamics in battery electrodes revealed by in situ and operando soft X-ray spectroscopy

PubMed Central

Liu, Xiaosong; Wang, Dongdong; Liu, Gao; Srinivasan, Venkat; Liu, Zhi; Hussain, Zahid; Yang, Wanli

2013-01-01

Developing high-performance batteries relies on material breakthroughs. During the past few years, various in situ characterization tools have been developed and have become indispensible in studying and the eventual optimization of battery materials. However, soft X-ray spectroscopy, one of the most sensitive probes of electronic states, has been mainly limited to ex situ experiments for battery research. Here we achieve in situ and operando soft X-ray absorption spectroscopy of lithium-ion battery cathodes. Taking advantage of the elemental, chemical and surface sensitivities of soft X-rays, we discover distinct lithium-ion and electron dynamics in Li(Co1/3Ni1/3Mn1/3)O2 and LiFePO4 cathodes in polymer electrolytes. The contrast between the two systems and the relaxation effect in LiFePO4 is attributed to a phase transformation mechanism, and the mesoscale morphology and charge conductivity of the electrodes. These discoveries demonstrate feasibility and power of in situ soft X-ray spectroscopy for studying integrated and dynamic effects in batteries. PMID:24100759

Effect of dissolved oxygen on two bacterial pathogens examined using ATR-FTIR spectroscopy, microelectrophoresis, and potentiometric titration.

PubMed

Castro, Felipe D; Sedman, Jacqueline; Ismail, Ashraf A; Asadishad, Bahareh; Tufenkji, Nathalie

2010-06-01

The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest. Titration of bacterial cells is used to identify the major proton-active functional groups and the overall concentration of these cell surface ligands at the cell membrane. Analysis of titration data shows notable differences between strains and conditions, confirming the appropriateness of this tool for an overall charge characterization. ATR-FTIR spectroscopy of whole cells is used to further characterize the bacterial biochemical composition and macromolecular structures that might be involved in the development of the net surficial charge of the organisms examined. The evaluation of the integrated intensities of HPO(2)(-) and carbohydrate absorption bands in the IR spectra reveals clear differences between growth protocols. Taken together, the three techniques seem to indicate that the dissolved oxygen tension during cell growth or acclimation can noticeably influence the expression of cell surface molecules and the measurable cell surface charge, though in a strain-dependent fashion.

Microstructural Characterization of Friction Stir Welded Aluminum-Steel Joints

NASA Astrophysics Data System (ADS)

Patterson, Erin E.; Hovanski, Yuri; Field, David P.

2016-06-01

This work focuses on the microstructural characterization of aluminum to steel friction stir welded joints. Lap weld configuration coupled with scribe technology used for the weld tool have produced joints of adequate quality, despite the significant differences in hardness and melting temperatures of the alloys. Common to friction stir processes, especially those of dissimilar alloys, are microstructural gradients including grain size, crystallographic texture, and precipitation of intermetallic compounds. Because of the significant influence that intermetallic compound formation has on mechanical and ballistic behavior, the characterization of the specific intermetallic phases and the degree to which they are formed in the weld microstructure is critical to predicting weld performance. This study used electron backscatter diffraction, energy dispersive spectroscopy, scanning electron microscopy, and Vickers micro-hardness indentation to explore and characterize the microstructures of lap friction stir welds between an applique 6061-T6 aluminum armor plate alloy and a RHA homogeneous armor plate steel alloy. Macroscopic defects such as micro-cracks were observed in the cross-sectional samples, and binary intermetallic compound layers were found to exist at the aluminum-steel interfaces of the steel particles stirred into the aluminum weld matrix and across the interfaces of the weld joints. Energy dispersive spectroscopy chemical analysis identified the intermetallic layer as monoclinic Al3Fe. Dramatic decreases in grain size in the thermo-mechanically affected zones and weld zones that evidenced grain refinement through plastic deformation and recrystallization. Crystallographic grain orientation and texture were examined using electron backscatter diffraction. Striated regions in the orientations of the aluminum alloy were determined to be the result of the severe deformation induced by the complex weld tool geometry. Many of the textures observed in the weld zone and thermo-mechanically affected zones exhibited shear texture components; however, there were many textures that deviated from ideal simple shear. Factors affecting the microstructure which are characteristic of the friction stir welding process, such as post-recrystallization deformation and complex deformation induced by tool geometry were discussed as causes for deviation from simple shear textures.

Protein folding on the ribosome studied using NMR spectroscopy

PubMed Central

Waudby, Christopher A.; Launay, Hélène; Cabrita, Lisa D.; Christodoulou, John

2013-01-01

NMR spectroscopy is a powerful tool for the investigation of protein folding and misfolding, providing a characterization of molecular structure, dynamics and exchange processes, across a very wide range of timescales and with near atomic resolution. In recent years NMR methods have also been developed to study protein folding as it might occur within the cell, in a de novo manner, by observing the folding of nascent polypeptides in the process of emerging from the ribosome during synthesis. Despite the 2.3 MDa molecular weight of the bacterial 70S ribosome, many nascent polypeptides, and some ribosomal proteins, have sufficient local flexibility that sharp resonances may be observed in solution-state NMR spectra. In providing information on dynamic regions of the structure, NMR spectroscopy is therefore highly complementary to alternative methods such as X-ray crystallography and cryo-electron microscopy, which have successfully characterized the rigid core of the ribosome particle. However, the low working concentrations and limited sample stability associated with ribosome–nascent chain complexes means that such studies still present significant technical challenges to the NMR spectroscopist. This review will discuss the progress that has been made in this area, surveying all NMR studies that have been published to date, and with a particular focus on strategies for improving experimental sensitivity. PMID:24083462

Pt decorated MoS2 nanoflakes for ultrasensitive resistive humidity sensor

NASA Astrophysics Data System (ADS)

Burman, Debasree; Santra, Sumita; Pramanik, Panchanan; Guha, Prasanta Kumar

2018-03-01

In this work, we report the fabrication of a low power, humidity sensor where platinum nanoparticles (NPs) decorated few-layered molybdenum disulphide (MoS2) nanoflakes have been used as the sensing layer. A mixed solvent was used to exfoliate the nanoflakes from the bulk powder. Then the Pt/MoS2 composites were prepared by reducing Pt NPs from chloroplatinic acid hexahydrate using a novel reduction technique using sulphide salt. The successful reduction and composite preparation were confirmed using various material characterization tools like scanning electron microscopy, atomic force microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy and UV-visible spectroscopy. The humidity sensors were prepared by drop-coating the Pt-decorated MoS2 on gold interdigitated electrodes and then exposed to various levels of relative humidity (RH). Composites with different weight ratios of Pt were tested and the best response was shown by the Pt/MoS2 (0.25:1) sample with a record high response of ˜4000 times at 85% RH. The response and recovery times were ˜92 s and ˜154 s respectively with repeatable behaviour. The sensor performance was found to be stable when tested over a few months. The underlying sensing mechanisms along with detailed characterization of the various composites have been discussed.

Key Exoplanets in the Era of JWST

NASA Astrophysics Data System (ADS)

Batalha, Natasha; Mandell, Avi; Lewis, Nikole K.; Pontoppidan, Klaus

2017-01-01

In 2018, exoplanet science will enter a new era with the launch of the James Webb Space Telescope (JWST). With JWST's observing power, several studies have sought to characterize how the instruments will perform and what atmospheric spectral features could theoretically be detected using transmission spectroscopy. With just two years left until launch, it is imperative that the exoplanet community begins to digest and integrate these studies into their observing plans and strategies. In order to encourage this and to allow all members of the community access to JWST simulations, we present here an open source tool for creating observation simulations of all observatory-supported time-series spectroscopy modes. We describe our tool, PandExo and use it to calculate the expected signal-to-noise ratio (SNR) for every confirmed planetary system with J<12. Assuming chemical equilibrium, we then determine how many observation hours are needed to attain a SNR of 5 on key molecular absorption bands of H2O, CH4, and CO. We end by determining the number of planets (hot Jupiters, warm Neptunes, super-Earths, etc.) that are currently attainable with JWST.

New Antifouling Platform Characterized by Single-Molecule Imaging

PubMed Central

2015-01-01

Antifouling surfaces have been widely studied for their importance in medical devices and industry. Antifouling surfaces mostly achieved by methoxy-poly(ethylene glycol) (mPEG) have shown biomolecular adsorption less than 1 ng/cm2 which was measured by surface analytical tools such as surface plasmon resonance (SPR) spectroscopy, quartz crystal microbalance (QCM), or optical waveguide lightmode (OWL) spectroscopy. Herein, we utilize a single-molecule imaging technique (i.e., an ultimate resolution) to study antifouling properties of functionalized surfaces. We found that about 600 immunoglobulin G (IgG) molecules are adsorbed. This result corresponds to ∼5 pg/cm2 adsorption, which is far below amount for the detection limit of the conventional tools. Furthermore, we developed a new antifouling platform that exhibits improved antifouling performance that shows only 78 IgG molecules adsorbed (∼0.5 pg/cm2). The antifouling platform consists of forming 1 nm TiO2 thin layer, on which peptidomimetic antifouling polymer (PMAP) is robustly anchored. The unprecedented antifouling performance can potentially revolutionize a variety of research fields such as single-molecule imaging, medical devices, biosensors, and others. PMID:24503420

New antifouling platform characterized by single-molecule imaging.

PubMed

Ryu, Ji Young; Song, In Taek; Lau, K H Aaron; Messersmith, Phillip B; Yoon, Tae-Young; Lee, Haeshin

2014-03-12

Antifouling surfaces have been widely studied for their importance in medical devices and industry. Antifouling surfaces mostly achieved by methoxy-poly(ethylene glycol) (mPEG) have shown biomolecular adsorption less than 1 ng/cm(2) which was measured by surface analytical tools such as surface plasmon resonance (SPR) spectroscopy, quartz crystal microbalance (QCM), or optical waveguide lightmode (OWL) spectroscopy. Herein, we utilize a single-molecule imaging technique (i.e., an ultimate resolution) to study antifouling properties of functionalized surfaces. We found that about 600 immunoglobulin G (IgG) molecules are adsorbed. This result corresponds to ∼5 pg/cm(2) adsorption, which is far below amount for the detection limit of the conventional tools. Furthermore, we developed a new antifouling platform that exhibits improved antifouling performance that shows only 78 IgG molecules adsorbed (∼0.5 pg/cm(2)). The antifouling platform consists of forming 1 nm TiO2 thin layer, on which peptidomimetic antifouling polymer (PMAP) is robustly anchored. The unprecedented antifouling performance can potentially revolutionize a variety of research fields such as single-molecule imaging, medical devices, biosensors, and others.

Nuclear magnetic resonance of polymer electrolyte membrane fuel cells.

PubMed

Suarez, Sophia; Greenbaum, Steve

2010-12-01

In this review, the contribution of NMR spectroscopy to the development of the proton exchange membrane fuel cell (PEMFC) is discussed, with particular emphasis on its use in the characterization of structure and transport in proton exchange membranes (PEMs). Owing to copious amount of information available, results of the past decade will be the main focal point. In addition, its use as a screening tool for the PEM materials will be discussed. Copyright © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Mechanical Anisotropy and Pressure Induced Structural Changes in Piroxicam Crystals Probed by In Situ Indentation and Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Manimunda, Praveena; Hintsala, Eric; Asif, Syed; Mishra, Manish Kumar

2017-01-01

The ability to correlate mechanical and chemical characterization techniques in real time is both lacking and powerful tool for gaining insights into material behavior. This is demonstrated through use of a novel nanoindentation device equipped with Raman spectroscopy to explore the deformation-induced structural changes in piroxicam crystals. Mechanical anisotropy was observed in two major faces ( 0bar{1}1 ) and (011), which are correlated to changes in the interlayer interaction from in situ Raman spectra recorded during indentation. The results of this study demonstrate the considerable potential of an in situ Raman nanoindentation instrument for studying a variety of topics, including stress-induced phase transformation mechanisms, mechanochemistry, and solid state reactivity under mechanical forces that occur in molecular and pharmaceutical solids.

Enhanced detection of aldehydes in Extra-Virgin Olive Oil by means of band selective NMR spectroscopy

NASA Astrophysics Data System (ADS)

Dugo, Giacomo; Rotondo, Archimede; Mallamace, Domenico; Cicero, Nicola; Salvo, Andrea; Rotondo, Enrico; Corsaro, Carmelo

2015-02-01

High resolution Nuclear Magnetic Resonance (NMR) spectroscopy is a very powerful tool for comprehensive food analyses and especially for Extra-Virgin Olive Oils (EVOOs). We use the NMR technique to study the spectral region of aldehydes (8-10 ppm) for EVOOs coming from the south part of Italy. We perform novel experiments by using mono and bidimensional band selective spin-echo pulse sequences and identify four structural classes of aldehydes in EVOOs. For the first time such species are identified in EVOOs without any chemical treatment; only dilution with CDCl3 is employed. This would allow the discrimination of different EVOOs for the aldehydes content increasing the potentiality of the NMR technique in the screening of metabolites for geographical characterization of EVOOs.

Detection of carotenoids present in blood of various animal species using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Liaqat, Maryam; Younus, Ayesha; Saleem, Muhammad; Rashid, Imaad; Yaseen, Maria; Jabeen, Saher

Raman spectroscopy is simple stable powerful diagnostic tool for body fluids, tissues and other biomolecules. Human blood possesses different kind of carotenoids that play a key role for protecting the cells from damaging by different viral and bacterial diseases. Carotenoids are antioxidative components which are capable to overcome the attack of different free radicals and reactive oxygen species. Carotenoids are not prepared by human body, therefore it is recommended to eat carotenoids enrich vegetable foods. No standard data is available on the concentration of useful carotenoids component in non-vegetable consumed items. In present research work, Raman spectroscopy is used to compare various blood components like plasma, serum, carotenoids present in blood of different animal species like goat, sheep, cow and buffalo consumed by human. Especially beta carotene is investigated. The Raman shift ranges from 600-1700 cm-1 for samples. Different characteristic peaks of the blood components are found which are not characterized before in animal samples. Doctrate Student in Photonics Deparatment of Electrical Engineering.

Low-temperature, ultrahigh-vacuum tip-enhanced Raman spectroscopy combined with molecular beam epitaxy for in situ two-dimensional materials' studies

NASA Astrophysics Data System (ADS)

Sheng, Shaoxiang; Li, Wenbin; Gou, Jian; Cheng, Peng; Chen, Lan; Wu, Kehui

2018-05-01

Tip-enhanced Raman spectroscopy (TERS), which combines scanning probe microscopy with the Raman spectroscopy, is capable to access the local structure and chemical information simultaneously. However, the application of ambient TERS is limited by the unstable and poorly controllable experimental conditions. Here, we designed a high performance TERS system based on a low-temperature ultrahigh-vacuum scanning tunneling microscope (LT-UHV-STM) and combined with a molecular beam epitaxy (MBE) system. It can be used for growing two-dimensional (2D) materials and for in situ STM and TERS characterization. Using a 2D silicene sheet on the Ag(111) surface as a model system, we achieved an unprecedented 109 Raman single enhancement factor in combination with a TERS spatial resolution down to 0.5 nm. The results show that TERS combined with a MBE system can be a powerful tool to study low dimensional materials and surface science.

Fourier transform near-infrared spectroscopy application for sea salt quality evaluation.

PubMed

Galvis-Sánchez, Andrea C; Lopes, João Almeida; Delgadillo, Ivonne; Rangel, António O S S

2011-10-26

Near-infrared (NIR) spectroscopy in diffuse reflectance mode was explored with the objective of discriminating sea salts according to their quality type (traditional salt vs "flower of salt") and geographical origin (Atlantic vs Mediterranean). Sea salts were also analyzed in terms of Ca(2+), Mg(2+), K(+), alkalinity, and sulfate concentrations to support spectroscopic results. High concentrations of Mg(2+) and K(+) characterized Atlantic samples, while a high Ca(2+) content was observed in traditional sea salts. A partial least-squares discriminant analysis model considering the 8500-7500 cm(-1) region permitted the discrimination of salts by quality types. The regions 4650-4350 and 5900-5500 cm(-1) allowed salts classification according to their geographical origin. It was possible to classify correctly 85.3 and 94.8% of the analyzed samples according to the salt type and to the geographical origin, respectively. These results demonstrated that NIR spectroscopy is a suitable and very efficient tool for sea salt quality evaluation.

Near-Infrared Spatially Resolved Spectroscopy for Tablet Quality Determination.

PubMed

Igne, Benoît; Talwar, Sameer; Feng, Hanzhou; Drennen, James K; Anderson, Carl A

2015-12-01

Near-infrared (NIR) spectroscopy has become a well-established tool for the characterization of solid oral dosage forms manufacturing processes and finished products. In this work, the utility of a traditional single-point NIR measurement was compared with that of a spatially resolved spectroscopic (SRS) measurement for the determination of tablet assay. Experimental designs were used to create samples that allowed for calibration models to be developed and tested on both instruments. Samples possessing a poor distribution of ingredients (highly heterogeneous) were prepared by under-blending constituents prior to compaction to compare the analytical capabilities of the two NIR methods. The results indicate that SRS can provide spatial information that is usually obtainable only through imaging experiments for the determination of local heterogeneity and detection of abnormal tablets that would not be detected with single-point spectroscopy, thus complementing traditional NIR measurement systems for in-line, and in real-time tablet analysis. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Chemical mapping and quantification at the atomic scale by scanning transmission electron microscopy.

PubMed

Chu, Ming-Wen; Chen, Cheng Hsuan

2013-06-25

With innovative modern material-growth methods, a broad spectrum of fascinating materials with reduced dimensions-ranging from single-atom catalysts, nanoplasmonic and nanophotonic materials to two-dimensional heterostructural interfaces-is continually emerging and extending the new frontiers of materials research. A persistent central challenge in this grand scientific context has been the detailed characterization of the individual objects in these materials with the highest spatial resolution, a problem prompting the need for experimental techniques that integrate both microscopic and spectroscopic capabilities. To date, several representative microscopy-spectroscopy combinations have become available, such as scanning tunneling microscopy, tip-enhanced scanning optical microscopy, atom probe tomography, scanning transmission X-ray microscopy, and scanning transmission electron microscopy (STEM). Among these tools, STEM boasts unique chemical and electronic sensitivity at unparalleled resolution. In this Perspective, we elucidate the advances in STEM and chemical mapping applications at the atomic scale by energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy with a focus on the ultimate challenge of chemical quantification with atomic accuracy.

Ultra-broadband THz time-domain spectroscopy of common polymers using THz air photonics.

PubMed

D'Angelo, Francesco; Mics, Zoltán; Bonn, Mischa; Turchinovich, Dmitry

2014-05-19

Terahertz-range dielectric properties of the common polymers low-density polyethylene (LDPE), cyclic olefin/ethylene copolymer (TOPAS®), polyamide-6 (PA6), and polytetrafluoroethylene (PTFE or Teflon®) are characterized in the ultra-broadband frequency window 2-15 THz, using a THz time-domain spectrometer employing air-photonics for the generation and detection of single-cycle sub-50 fs THz transients. The time domain measurements provide direct access to both the absorption and refractive index spectra. The polymers LDPE and TOPAS® demonstrate negligible absorption and spectrally-flat refractive index across the entire spectroscopy window, revealing the high potential of these polymers for applications in THz photonics such as ultra-broadband polymer-based dielectric mirrors, waveguides, and fibers. Resonant high-frequency polar vibrational modes are observed and assigned in polymers PA6 and PTFE, and their dielectric functions in the complete frequency window 2-15 THz are theoretically reproduced. Our results demonstrate the potential of ultra-broadband air-photonics-based THz time domain spectroscopy as a valuable analytic tool for materials science.

Infrared Spectroscopy as a Chemical Fingerprinting Tool

NASA Technical Reports Server (NTRS)

Huff, Tim; Munafo, Paul M. (Technical Monitor)

2002-01-01

Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. The technique is rapid, reproducible and usually non-invasive. With the appropriate accessories, the technique can be used to examine samples in either a solid, liquid or gas phase. Solid samples of varying sizes and shapes may be used, and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be examined. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Both aqueous and non-aqueous free-flowing solutions can be analyzed using appropriate IR techniques, as can viscous liquids such as heavy oils and greases. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

Raman-in-SEM, a multimodal and multiscale analytical tool: performance for materials and expertise.

PubMed

Wille, Guillaume; Bourrat, Xavier; Maubec, Nicolas; Lahfid, Abdeltif

2014-12-01

The availability of Raman spectroscopy in a powerful analytical scanning electron microscope (SEM) allows morphological, elemental, chemical, physical and electronic analysis without moving the sample between instruments. This paper documents the metrological performance of the SEMSCA commercial Raman interface operated in a low vacuum SEM. It provides multiscale and multimodal analyses as Raman/EDS, Raman/cathodoluminescence or Raman/STEM (STEM: scanning transmission electron microscopy) as well as Raman spectroscopy on nanomaterials. Since Raman spectroscopy in a SEM can be influenced by several SEM-related phenomena, this paper firstly presents a comparison of this new tool with a conventional micro-Raman spectrometer. Then, some possible artefacts are documented, which are due to the impact of electron beam-induced contamination or cathodoluminescence contribution to the Raman spectra, especially with geological samples. These effects are easily overcome by changing or adapting the Raman spectrometer and the SEM settings and methodology. The deletion of the adverse effect of cathodoluminescence is solved by using a SEM beam shutter during Raman acquisition. In contrast, this interface provides the ability to record the cathodoluminescence (CL) spectrum of a phase. In a second part, this study highlights the interest and efficiency of the coupling in characterizing micrometric phases at the same point. This multimodal approach is illustrated with various issues encountered in geosciences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microstructural Study of Micron-Sized Craters Simulating Stardust Impacts in Aluminum 1100 Targets

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Borg, Janet; Troadec, David; Djouadi, Zahia; Horz, Friedrich

2006-01-01

Various microscopic techniques were used to characterize experimental micro- craters in aluminium foils to prepare for the comprehensive analysis of the cometary and interstellar particle impacts in aluminium foils to be returned by the Stardust mission. First, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) were used to study the morphology of the impact craters and the bulk composition of the residues left by soda-lime glass impactors. A more detailed structural and compositional study of impactor remnants was then performed using TEM (Transmission Electron Microscopy), EDS, and electron diffraction methods. The TEM samples were prepared by Focused Ion Beam (FIB) methods. This technique proved to be especially valuable in studying impact crater residues and impact crater morphology. Finally, we also showed that InfraRed microscopy (IR) can be a quick and reliable tool for such investigations. The combination of all of these tools enables a complete microscopic characterization of the craters.

Electron energy loss spectroscopy on semiconductor heterostructures for optoelectronics and photonics applications.

PubMed

Eljarrat, A; López-Conesa, L; Estradé, S; Peiró, F

2016-05-01

In this work, we present characterization methods for the analysis of nanometer-sized devices, based on silicon and III-V nitride semiconductor materials. These methods are devised in order to take advantage of the aberration corrected scanning transmission electron microscope, equipped with a monochromator. This set-up ensures the necessary high spatial and energy resolution for the characterization of the smallest structures. As with these experiments, we aim to obtain chemical and structural information, we use electron energy loss spectroscopy (EELS). The low-loss region of EELS is exploited, which features fundamental electronic properties of semiconductor materials and facilitates a high data throughput. We show how the detailed analysis of these spectra, using theoretical models and computational tools, can enhance the analytical power of EELS. In this sense, initially, results from the model-based fit of the plasmon peak are presented. Moreover, the application of multivariate analysis algorithms to low-loss EELS is explored. Finally, some physical limitations of the technique, such as spatial delocalization, are mentioned. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

The application of atomic force microscopy in mineral flotation.

PubMed

Xing, Yaowen; Xu, Mengdi; Gui, Xiahui; Cao, Yijun; Babel, Bent; Rudolph, Martin; Weber, Stefan; Kappl, Michael; Butt, Hans-Jürgen

2018-06-01

During the past years, atomic force microscopy (AFM) has matured to an indispensable tool to characterize nanomaterials in colloid and interface science. For imaging, a sharp probe mounted near to the end of a cantilever scans over the sample surface providing a high resolution three-dimensional topographic image. In addition, the AFM tip can be used as a force sensor to detect local properties like adhesion, stiffness, charge etc. After the invention of the colloidal probe technique it has also become a major method to measure surface forces. In this review, we highlight the advances in the application of AFM in the field of mineral flotation, such as mineral morphology imaging, water at mineral surface, reagent adsorption, inter-particle force, and bubble-particle interaction. In the coming years, the complementary characterization of chemical composition such as using infrared spectroscopy and Raman spectroscopy for AFM topography imaging and the synchronous measurement of the force and distance involving deformable bubble as a force sensor will further assist the fundamental understanding of flotation mechanism. Copyright © 2018 Elsevier B.V. All rights reserved.

Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms.

PubMed

Woltmann, Eva; Meyer, Hans; Weigel, Diana; Pritzke, Heinz; Posch, Tjorben N; Kler, Pablo A; Schürmann, Klaus; Roscher, Jörg; Huhn, Carolin

2014-10-01

High production output of solid pharmaceutical formulations requires fast methods to ensure their quality. Likewise, fast analytical procedures are required in forensic sciences, for example at customs, to substantiate an initial suspicion. We here present the design and the optimization of an instrumental setup for rapid and non-invasive characterization of tablets by laser-induced fluorescence spectroscopy (with a UV-laser (λ ex = 266 nm) as excitation source) in reflection geometry. The setup was first validated with regard to repeatability, bleaching phenomena, and sensitivity. The effect on the spectra by the physical and chemical properties of the samples, e.g. their hardness, homogeneity, chemical composition, and granule grain size of the uncompressed material, using a series of tablets, manufactured in accordance with design of experiments, was investigated. Investigation of tablets with regard to homogeneity, especially, is extremely important in pharmaceutical production processes. We demonstrate that multiplicative scatter correction is an appropriate tool for data preprocessing of fluorescence spectra. Tablets with different physical and chemical characteristics can be discriminated well from their fluorescence spectra by subjecting the results to principal component analysis.

A reliable confirmation of the chemical structure of synthetic oligonucleotides: Detection of active protons in DNA oligomers by low-temperature FT infrared spectroscopy

NASA Astrophysics Data System (ADS)

Rozenberg, M.; Shoham, G.

2009-01-01

Cooling the samples allowed us to characterize solid oligonucleotides such as dimers, trimers and pentamers of cytidine, for the first time, in the IR range of the out-of-plane bending molecular modes (1000-400 cm -1) at 20 K. Especially interesting are the narrow IR bands of the out-of-plane bending ν4 NH 2 proton mode, which are apparently invisible at room temperature. This unequivocally defined and well-resolved NH 2 bending band should provide important information on the exact chemical form and hydrogen bonding interactions of cytidine amine groups. As such, this unique IR spectroscopy is suggested as a practical analytical tool to validate and characterize synthetic DNA bases and oligonucleotides. Using an approach of this type it was found that desalted oligonucleotide samples of the same nominal composition, but which had been produced by three different manufacturers, differ significantly in their IR spectra. These data suggest that the presumably identical oligonucleotides are in fact different, at least with respect to the content and nature of their NH protons.

A reliable confirmation of the chemical structure of synthetic oligonucleotides: detection of active protons in DNA oligomers by low-temperature FT infrared spectroscopy.

PubMed

Rozenberg, M; Shoham, G

2009-01-01

Cooling the samples allowed us to characterize solid oligonucleotides such as dimers, trimers and pentamers of cytidine, for the first time, in the IR range of the out-of-plane bending molecular modes (1000-400 cm(-1)) at 20K. Especially interesting are the narrow IR bands of the out-of-plane bending nu(4) NH(2) proton mode, which are apparently invisible at room temperature. This unequivocally defined and well-resolved NH(2) bending band should provide important information on the exact chemical form and hydrogen bonding interactions of cytidine amine groups. As such, this unique IR spectroscopy is suggested as a practical analytical tool to validate and characterize synthetic DNA bases and oligonucleotides. Using an approach of this type it was found that desalted oligonucleotide samples of the same nominal composition, but which had been produced by three different manufacturers, differ significantly in their IR spectra. These data suggest that the presumably identical oligonucleotides are in fact different, at least with respect to the content and nature of their NH protons.

Using thermal infrared (TIR) data to characterize dust sources, dust fall and the linkage to climate in the Middle East

NASA Astrophysics Data System (ADS)

Mohammad, R.; Ramsey, M.; Scheidt, S. P.

2010-12-01

Prior to mineral dust deposition affecting albedo, aerosols can have direct and indirect effects on local to regional scale climate by changing both the shortwave and longwave radiative forcing. In addition, mineral dust causes health hazards, such as respiratory-related illnesses and deaths, loss of agricultural soil, and safety hazards to aviation and motorists due to reduced visibility. Previous work utilized satellite and ground-based TIR data to describe the direct longwave radiative effect of the Saharan Air Layer (SAL) over the Atlantic Ocean originating from dust storms in the Western Sahara. TIR emission spectroscopy was used to identify the spectral absorption features of that dust. The current research focuses on Kuwait and utilizes a comprehensive set of spatial, analytical and geological tools to characterize dust emissions and its radiative effects. Surface mineral composition maps for the Kuwait region were created using ASTER images and GIS datasets in order to identify the possible sources of wind-blown dust. Backward trajectory analysis using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests the dust source areas were located in Iraq, Syria, Jordan and Saudi Arabia. Samples collected from two dust storms (May and July 2010) were analyzed for their mineral composition and to validate the dust source areas identified by the modeling and remote sensing analysis. These air fall dust samples were collected in glass containers on a 13 meter high rooftop in the suburb of Rumaithiya in Kuwait. Additional samples will be collected to expand the analysis and their chemical compositions will be characterized by a combination of laboratory X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM) and TIR emission spectroscopy. The overarching objective of this ongoing research is to both characterize the effects of mineral dust on climate as well as establish a predictive tool that can identify dust storm sources and potentially aid in establishing a more accurate prediction and warning system in the Middle East region.

Synthesis and characterization of germa[n]pericyclynes.

PubMed

Tanimoto, Hiroki; Nagao, Tomohiko; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Iseda, Fumiyasu; Nagato, Yuko; Suzuka, Toshimasa; Tsutsumi, Ken; Kakiuchi, Kiyomi

2014-06-14

The synthesis and characterization of novel pericyclynes comprising germanium atoms and acetylenes, germa[n]pericyclynes, are described. The prepared germa[4]-, [6]-, and [8]pericyclynes were compared by (13)C NMR spectroscopy, X-ray crystallography, cyclic voltammetry, UV-visible spectroscopy, fluorescence emission spectroscopy, Raman spectroscopy, and density functional theory calculation analyses.

Direct Force Measurements of Receptor-Ligand Interactions on Living Cells

NASA Astrophysics Data System (ADS)

Eibl, Robert H.

The characterization of cell adhesion between two living cells at the level of single receptor-ligand bonds is an experimental challenge. This chapter describes how the extremely sensitive method of atomic force microscopy (AFM) based force spectroscopy can be applied to living cells in order to probe for cell-to-cell or cell-to-substrate interactions mediated by single pairs of adhesion receptors. In addition, it is outlined how single-molecule AFM force spectroscopy can be used to detect physiologic changes of an adhesion receptor in a living cell. This force spectroscopy allows us to detect in living cells rapidly changing, chemokine SDF-1 triggered activation states of single VLA-4 receptors. This recently developed AFM application will allow for the detailed investigation of the integrin-chemokine crosstalk of integrin activation mechanisms and on how other adhesion receptors are modulated in health and disease. As adhesion molecules, living cells and even bacteria can be studied by single-molecule AFM force spectroscopy, this method is set to become a powerful tool that can not only be used in biophysics, but in cell biology as well as in immunology and cancer research.

Novel single-cell functional analysis of red blood cells using laser tweezers Raman spectroscopy: application for sickle cell disease.

PubMed

Liu, Rui; Mao, Ziliang; Matthews, Dennis L; Li, Chin-Shang; Chan, James W; Satake, Noriko

2013-07-01

Laser tweezers Raman spectroscopy was used to characterize the oxygenation response of single normal adult, sickle, and cord blood red blood cells (RBCs) to an applied mechanical force. Individual cells were subjected to different forces by varying the laser power of a single-beam optical trap, and the intensities of several oxygenation-specific Raman spectral peaks were monitored to determine the oxygenation state of the cells. For all three cell types, an increase in laser power (or mechanical force) induced a greater deoxygenation of the cell. However, sickle RBCs deoxygenated more readily than normal RBCs when subjected to the same optical forces. Conversely, cord blood RBCs were able to maintain their oxygenation better than normal RBCs. These results suggest that differences in the chemical or mechanical properties of fetal, normal, and sickle cells affect the degree to which applied mechanical forces can deoxygenate the cell. Populations of normal, sickle, and cord RBCs were identified and discriminated based on this mechanochemical phenomenon. This study demonstrates the potential application of laser tweezers Raman spectroscopy as a single-cell, label-free analytical tool to characterize the functional (e.g., mechanical deformability, oxygen binding) properties of normal and diseased RBCs. Copyright © 2013 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

A Novel Method for Preparation of Gold NanoBipyramids Using Microwave Irradiation and Its Application in Immunosensors

NASA Astrophysics Data System (ADS)

Huynh, Trong Phat; Ngo, Vo Ke Thanh; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Nghiem, Quoc Dat; Lam, Quang Vinh; Huynh, Thanh Dat

2016-05-01

Gold nanobipyramids (NBPs) have attracted attention for producing smart sensing devices as diagnostic tools in biotechnological and medical applications, because they show more advantageous plasmonic properties than comparable gold nanorods. Normally, NBPs were synthesized using seed-mediated growth process at room temperature. In this report, our group describes a method for synthesising of NBPs using microwave irradiation with ascorbic acid reduction and cetyltrimethylammonium bromide + silver nitrate (AgNO3) as capping agents. The advantages of this method are a highly effective approach to fast and uniform NBPs. The product was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and x-ray powder diffraction. As an application in quartz crystal microbalance immunosensors, NBPs is conjugated with the chloramphenicol antibodies for signal amplification to detect chloramphenicol residuals in the QCM system.

Current-voltage characteristics and transition voltage spectroscopy of individual redox proteins.

PubMed

Artés, Juan M; López-Martínez, Montserrat; Giraudet, Arnaud; Díez-Pérez, Ismael; Sanz, Fausto; Gorostiza, Pau

2012-12-19

Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current-voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins.

Interfacial Microstructure and Mechanical Properties of Friction Stir Welded Joints of Commercially Pure Aluminum and 304 Stainless Steel

NASA Astrophysics Data System (ADS)

Murugan, Balamagendiravarman; Thirunavukarasu, Gopinath; Kundu, Sukumar; Kailas, Satish V.; Chatterjee, Subrata

2018-05-01

In the present investigation, friction stir welding of commercially pure aluminum and 304 stainless steel was carried out at varying tool rotational speeds from 200 to 1000 rpm in steps of 200 rpm using 60 mm/min traverse speed at 2 (degree) tool tilt angle. Microstructural characterization of the interfacial zone was carried out using optical microscope and scanning electron microscope. Energy-dispersive spectroscopy indicated the presence of FeAl3 intermetallic phase. Thickness of the intermetallic layer increased with the increase in tool rotational speed. X-ray diffraction studies indicated the formation of intermetallic phases like FeAl2, Fe4Al13, Fe2Al5, and FeAl3. A maximum tensile strength of 90% that of aluminum along with 4.5% elongation was achieved with the welded sample at tool rotational speed of 400 rpm. The stir zone showed higher hardness as compared to base metals, heat affected zone, and thermo-mechanically affected zone due to the presence of intermetallics. The maximum hardness value at the stir zone was achieved at 1000 rpm tool rotational speed.

Fast Track Characterization of Highly Radioactive Waste Pits Combining Off-the-Shelf Robotics with Innovative Investigation Protocols

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

Chabeuf, Jean-Michel; Boya, Didier

The investigation and characterization of radioactive waste pits and effluent storage tanks represents a substantial and challenging step in the overall decommissioning programme launched by AREVA NC in 1998 on the site of Marcoule on behalf of the French Atomic Energy commission. Physical ,radiological and regulatory constraints, combined with a tight schedule, have lead our teams to use proven conventional instrumentation and robotics in innovative configurations . One such investigation, conducted on a particularly challenging radioactive effluent storage pit, is described below. The 'H' pit is a stainless steel clad concrete cavity, located in the second basement of the de-claddingmore » building of Marcoule site. It was used for forty years as buffer storage for high activity effluents and has a length of 5 meters, a width of 3 meters , a height of 2.5 meters, and is topped by lead plates over 5 cm thick and The bottom of the cavity is covered with a layer of mud containing mainly graphite, diatoms and resins. The mud level ranges from about 20 centimeters to over 50 centimeters. The overall mud volume is around 2.4 cubic meters. Ambient dose rates above the lead plates exceed 10 mSv/h. The main purpose of our investigation was to characterize the muds for future recovery and conditioning prior to decontaminating the pit. The history of the pit together with the varying mud altimetry lead us to believe that sedimentation had probably occurred throughout the years. We thus decided to combine dose rate measurements using IF104 probes, gamma spectroscopy with CdTe probes and sample collections at different depths to ensure the representativeness and full characterization of the muds. Poor access, ambient dose rates have lead us to conceive a robotic arm, mounted on an shaft which can be modified to fit a wide range of pits and tanks. Custom built robotic tools with maximum manoeuvrability generally involve costs and delays far exceeding our purposes. SIT, a French manufacturer of high precision handling equipment for the nuclear industry, supplied us with a user customized 'Python' Robotic arm and the associated computerized command and control equipment within 6 months of the order. The arm allowed the necessary free movement for a precise characterization of the entire pit while being flexible enough to carry varying measuring and sample collection tools. Investigations included video imaging, precise dimensional checks, collection of effluent samples, gamma spectroscopy and collimated dose rate measurements. Specific tooling and arm extensions were created by SIT for each measurement type. The investigations were conducted successfully, providing a detailed view of the pit condition, a complete mapping of collimated dose rates, a grid of gamma spectroscopy, as well as 8 samples of radioactive mud which were subsequently analyzed in our laboratory . A simple yet innovative technology allowed us to fully characterize this pit and its content within a time frame of less than Eight months We subsequently developed a mud recovery scenario, a process for the conditioning of radioactive muds by cementation, and a complete scenario for the pit decontamination and dismantling. The robotic arm is now being used for the characterization and decontamination of other similar environments on the site of Marcoule.« less

A grid matrix-based Raman spectroscopic method to characterize different cell milieu in biopsied axillary sentinel lymph nodes of breast cancer patients.

PubMed

Som, Dipasree; Tak, Megha; Setia, Mohit; Patil, Asawari; Sengupta, Amit; Chilakapati, C Murali Krishna; Srivastava, Anurag; Parmar, Vani; Nair, Nita; Sarin, Rajiv; Badwe, R

2016-01-01

Raman spectroscopy which is based upon inelastic scattering of photons has a potential to emerge as a noninvasive bedside in vivo or ex vivo molecular diagnostic tool. There is a need to improve the sensitivity and predictability of Raman spectroscopy. We developed a grid matrix-based tissue mapping protocol to acquire cellular-specific spectra that also involved digital microscopy for localizing malignant and lymphocytic cells in sentinel lymph node biopsy sample. Biosignals acquired from specific cellular milieu were subjected to an advanced supervised analytical method, i.e., cross-correlation and peak-to-peak ratio in addition to PCA and PC-LDA. We observed decreased spectral intensity as well as shift in the spectral peaks of amides and lipid bands in the completely metastatic (cancer cells) lymph nodes with high cellular density. Spectral library of normal lymphocytes and metastatic cancer cells created using the cellular specific mapping technique can be utilized to create an automated smart diagnostic tool for bench side screening of sampled lymph nodes. Spectral library of normal lymphocytes and metastatic cancer cells created using the cellular specific mapping technique can be utilized to develop an automated smart diagnostic tool for bench side screening of sampled lymph nodes supported by ongoing global research in developing better technology and signal and big data processing algorithms.

High-Resolution Integrated Optical System

NASA Astrophysics Data System (ADS)

Prakapenka, V. B.; Goncharov, A. F.; Holtgrewe, N.; Greenberg, E.

2017-12-01

Raman and optical spectroscopy in-situ at extreme high pressure and temperature conditions relevant to the planets' deep interior is a versatile tool for characterization of wide range of properties of minerals essential for understanding the structure, composition, and evolution of terrestrial and giant planets. Optical methods, greatly complementing X-ray diffraction and spectroscopy techniques, become crucial when dealing with light elements. Study of vibrational and optical properties of minerals and volatiles, was a topic of many research efforts in past decades. A great deal of information on the materials properties under extreme pressure and temperature has been acquired including that related to structural phase changes, electronic transitions, and chemical transformations. These provide an important insight into physical and chemical states of planetary interiors (e.g. nature of deep reservoirs) and their dynamics including heat and mass transport (e.g. deep carbon cycle). Optical and vibrational spectroscopy can be also very instrumental for elucidating the nature of the materials molten states such as those related to the Earth's volatiles (CO2, CH4, H2O), aqueous fluids and silicate melts, planetary ices (H2O, CH4, NH3), noble gases, and H2. The optical spectroscopy study performed concomitantly with X-ray diffraction and spectroscopy measurements at the GSECARS beamlines on the same sample and at the same P-T conditions would greatly enhance the quality of this research and, moreover, will provide unique new information on chemical state of matter. The advanced high-resolution user-friendly integrated optical system is currently under construction and expected to be completed by 2018. In our conceptual design we have implemented Raman spectroscopy with five excitation wavelengths (266, 473, 532, 660, 946 nm), confocal imaging, double sided IR laser heating combined with high temperature Raman (including coherent anti-Stokes Raman scattering) and transient (based on a bright supercontinuum light source) spectroscopies in a wide spectral range (200-1600 nm). Details and future combination of this innovative system with high-resolution synchrotron micro-diffraction at GSECARS for full characterization of materials in-situ at extreme conditions will be discussed.

Study of PVD AlCrN Coating for Reducing Carbide Cutting Tool Deterioration in the Machining of Titanium Alloys.

PubMed

Cadena, Natalia L; Cue-Sampedro, Rodrigo; Siller, Héctor R; Arizmendi-Morquecho, Ana M; Rivera-Solorio, Carlos I; Di-Nardo, Santiago

2013-05-24

The manufacture of medical and aerospace components made of titanium alloys and other difficult-to-cut materials requires the parallel development of high performance cutting tools coated with materials capable of enhanced tribological and resistance properties. In this matter, a thin nanocomposite film made out of AlCrN (aluminum-chromium-nitride) was studied in this research, showing experimental work in the deposition process and its characterization. A heat-treated monolayer coating, competitive with other coatings in the machining of titanium alloys, was analyzed. Different analysis and characterizations were performed on the manufactured coating by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDXS), and X-ray diffraction (XRD). Furthermore, the mechanical behavior of the coating was evaluated through hardness test and tribology with pin-on-disk to quantify friction coefficient and wear rate. Finally, machinability tests using coated tungsten carbide cutting tools were executed in order to determine its performance through wear resistance, which is a key issue of cutting tools in high-end cutting at elevated temperatures. It was demonstrated that the specimen (with lower friction coefficient than previous research) is more efficient in machinability tests in Ti6Al4V alloys. Furthermore, the heat-treated monolayer coating presented better performance in comparison with a conventional monolayer of AlCrN coating.

Study of PVD AlCrN Coating for Reducing Carbide Cutting Tool Deterioration in the Machining of Titanium Alloys

PubMed Central

Cadena, Natalia L.; Cue-Sampedro, Rodrigo; Siller, Héctor R.; Arizmendi-Morquecho, Ana M.; Rivera-Solorio, Carlos I.; Di-Nardo, Santiago

2013-01-01

The manufacture of medical and aerospace components made of titanium alloys and other difficult-to-cut materials requires the parallel development of high performance cutting tools coated with materials capable of enhanced tribological and resistance properties. In this matter, a thin nanocomposite film made out of AlCrN (aluminum–chromium–nitride) was studied in this research, showing experimental work in the deposition process and its characterization. A heat-treated monolayer coating, competitive with other coatings in the machining of titanium alloys, was analyzed. Different analysis and characterizations were performed on the manufactured coating by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDXS), and X-ray diffraction (XRD). Furthermore, the mechanical behavior of the coating was evaluated through hardness test and tribology with pin-on-disk to quantify friction coefficient and wear rate. Finally, machinability tests using coated tungsten carbide cutting tools were executed in order to determine its performance through wear resistance, which is a key issue of cutting tools in high-end cutting at elevated temperatures. It was demonstrated that the specimen (with lower friction coefficient than previous research) is more efficient in machinability tests in Ti6Al4V alloys. Furthermore, the heat-treated monolayer coating presented better performance in comparison with a conventional monolayer of AlCrN coating. PMID:28809266

High-throughput electrical measurement and microfluidic sorting of semiconductor nanowires.

PubMed

Akin, Cevat; Feldman, Leonard C; Durand, Corentin; Hus, Saban M; Li, An-Ping; Hui, Ho Yee; Filler, Michael A; Yi, Jingang; Shan, Jerry W

2016-05-24

Existing nanowire electrical characterization tools not only are expensive and require sophisticated facilities, but are far too slow to enable statistical characterization of highly variable samples. They are also generally not compatible with further sorting and processing of nanowires. Here, we demonstrate a high-throughput, solution-based electro-orientation-spectroscopy (EOS) method, which is capable of automated electrical characterization of individual nanowires by direct optical visualization of their alignment behavior under spatially uniform electric fields of different frequencies. We demonstrate that EOS can quantitatively characterize the electrical conductivities of nanowires over a 6-order-of-magnitude range (10(-5) to 10 S m(-1), corresponding to typical carrier densities of 10(10)-10(16) cm(-3)), with different fluids used to suspend the nanowires. By implementing EOS in a simple microfluidic device, continuous electrical characterization is achieved, and the sorting of nanowires is demonstrated as a proof-of-concept. With measurement speeds two orders of magnitude faster than direct-contact methods, the automated EOS instrument enables for the first time the statistical characterization of highly variable 1D nanomaterials.

Increasing rigor in NMR-based metabolomics through validated and open source tools

PubMed Central

Eghbalnia, Hamid R; Romero, Pedro R; Westler, William M; Baskaran, Kumaran; Ulrich, Eldon L; Markley, John L

2016-01-01

The metabolome, the collection of small molecules associated with an organism, is a growing subject of inquiry, with the data utilized for data-intensive systems biology, disease diagnostics, biomarker discovery, and the broader characterization of small molecules in mixtures. Owing to their close proximity to the functional endpoints that govern an organism’s phenotype, metabolites are highly informative about functional states. The field of metabolomics identifies and quantifies endogenous and exogenous metabolites in biological samples. Information acquired from nuclear magnetic spectroscopy (NMR), mass spectrometry (MS), and the published literature, as processed by statistical approaches, are driving increasingly wider applications of metabolomics. This review focuses on the role of databases and software tools in advancing the rigor, robustness, reproducibility, and validation of metabolomics studies. PMID:27643760

Increasing rigor in NMR-based metabolomics through validated and open source tools.

PubMed

Eghbalnia, Hamid R; Romero, Pedro R; Westler, William M; Baskaran, Kumaran; Ulrich, Eldon L; Markley, John L

2017-02-01

The metabolome, the collection of small molecules associated with an organism, is a growing subject of inquiry, with the data utilized for data-intensive systems biology, disease diagnostics, biomarker discovery, and the broader characterization of small molecules in mixtures. Owing to their close proximity to the functional endpoints that govern an organism's phenotype, metabolites are highly informative about functional states. The field of metabolomics identifies and quantifies endogenous and exogenous metabolites in biological samples. Information acquired from nuclear magnetic spectroscopy (NMR), mass spectrometry (MS), and the published literature, as processed by statistical approaches, are driving increasingly wider applications of metabolomics. This review focuses on the role of databases and software tools in advancing the rigor, robustness, reproducibility, and validation of metabolomics studies. Copyright © 2016. Published by Elsevier Ltd.

Identification of anisodamine tablets by Raman and near-infrared spectroscopy with chemometrics.

PubMed

Li, Lian; Zang, Hengchang; Li, Jun; Chen, Dejun; Li, Tao; Wang, Fengshan

2014-06-05

Vibrational spectroscopy including Raman and near-infrared (NIR) spectroscopy has become an attractive tool for pharmaceutical analysis. In this study, effective calibration models for the identification of anisodamine tablet and its counterfeit and the distinguishment of manufacturing plants, based on Raman and NIR spectroscopy, were built, respectively. Anisodamine counterfeit tablets were identified by Raman spectroscopy with correlation coefficient method, and the results showed that the predictive accuracy was 100%. The genuine anisodamine tablets from 5 different manufacturing plants were distinguished by NIR spectroscopy using partial least squares discriminant analysis (PLS-DA) models based on interval principal component analysis (iPCA) method. And the results showed the recognition rate and rejection rate were 100% respectively. In conclusion, Raman spectroscopy and NIR spectroscopy combined with chemometrics are feasible and potential tools for rapid pharmaceutical tablet discrimination. Copyright © 2014 Elsevier B.V. All rights reserved.

Electron microscopy localization and characterization of functionalized composite organic-inorganic SERS nanoparticles on leukemia cells.

PubMed

Koh, Ai Leen; Shachaf, Catherine M; Elchuri, Sailaja; Nolan, Garry P; Sinclair, Robert

2008-12-01

We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic nanoparticle (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet scanning electron microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron (BSE) detector was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution transmission electron microscopy (TEM) images and scanning Auger electron spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens.

Electron Microscopy Localization and Characterization of Functionalized Composite Organic-Inorganic SERS Nanoparticles on Leukemia Cells

PubMed Central

Koh, Ai Leen; Shachaf, Catherine M.; Elchuri, Sailaja; Nolan, Garry P.; Sinclair, Robert

2008-01-01

We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet Scanning Electron Microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron detector (BSE) was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution Transmission Electron Microscope (TEM) images and Scanning Auger Electron Spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens. PMID:18995965

Atomic-Scale Characterization of Oxide Interfaces and Superlattices Using Scanning Transmission Electron Microscopy

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

Spurgeon, Steven R.; Chambers, Scott A.

Scanning transmission electron microscopy (STEM) has become one of the fundamental tools to characterize oxide interfaces and superlattices. Atomic-scale structure, chemistry, and composition mapping can now be conducted on a wide variety of materials systems thanks to the development of aberration-correctors and advanced detectors. STEM imaging and diffraction, coupled with electron energy loss (EELS) and energy-dispersive X-ray (EDS) spectroscopies, offer unparalleled, high-resolution analysis of structure-property relationships. In this chapter we highlight investigations into key phenomena, including interfacial conductivity in oxide superlattices, charge screening effects in magnetoelectric heterostructures, the design of high-quality iron oxide interfaces, and the complex physics governing atomic-scalemore » chemical mapping. These studies illustrate how unique insights from STEM characterization can be integrated with other techniques and first-principles calculations to develop better models for the behavior of functional oxides.« less

Facile Purification of Milligram to Gram Quantities of Condensed Tannins According to Mean Degree of Polymerization and Flavan-3-ol Subunit Composition.

PubMed

Brown, Ron H; Mueller-Harvey, Irene; Zeller, Wayne E; Reinhardt, Laurie; Stringano, Elisabetta; Gea, An; Drake, Christopher; Ropiak, Honorata M; Fryganas, Christos; Ramsay, Aina; Hardcastle, Emily E

2017-09-13

Unambiguous investigation of condensed tannin (CT) structure-activity relationships in biological systems requires well-characterized, high-purity CTs. Sephadex LH-20 and Toyopearl HW-50F resins were compared for separating CTs from acetone/water extracts, and column fractions analyzed for flavan-3-ol subunits, mean degree of polymerization (mDP), and purity. Toyopearl HW-50F generated fractions with higher mDP values and better separation of procyanidins (PC) and prodelphinidins (PD) but required a prepurification step, needed more time for large scale purifications, and gave poorer recoveries. Therefore, two gradient elution schemes were developed for CT purification on Sephadex LH-20 providing 146-2000 mg/fraction. Fractions were analyzed by thiolysis and NMR spectroscopy. In general, PC/PD ratios decreased and mDP increased during elution. 1 H NMR spectroscopy served as a rapid screening tool to qualitatively determine CT enrichment and carbohydrate impurities present, guiding fractionation toward repurification or 1 H- 13 C HSQC NMR spectroscopy and thiolysis. These protocols provide options for preparing highly pure CT samples.

Light trapping in thin-film solar cells measured by Raman spectroscopy

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

Ledinský, M., E-mail: ledinsky@fzu.cz; Photovoltaics and Thin Film Electronics Laboratory, Institute of Microengineering; Moulin, E.

2014-09-15

In this study, Raman spectroscopy is used as a tool to determine the light-trapping capability of textured ZnO front electrodes implemented in microcrystalline silicon (μc-Si:H) solar cells. Microcrystalline silicon films deposited on superstrates of various roughnesses are characterized by Raman micro-spectroscopy at excitation wavelengths of 442 nm, 514 nm, 633 nm, and 785 nm, respectively. The way to measure quantitatively and with a high level of reproducibility the Raman intensity is described in details. By varying the superstrate texture and with it the light trapping in the μc-Si:H absorber layer, we find significant differences in the absolute Raman intensity measured in the near infraredmore » wavelength region (where light trapping is relevant). A good agreement between the absolute Raman intensity and the external quantum efficiency of the μc-Si:H solar cells is obtained, demonstrating the validity of the introduced method. Applications to thin-film solar cells, in general, and other optoelectronic devices are discussed.« less

Detecting Damage in Composite Material Using Nonlinear Elastic Wave Spectroscopy Methods

NASA Astrophysics Data System (ADS)

Meo, Michele; Polimeno, Umberto; Zumpano, Giuseppe

2008-05-01

Modern aerospace structures make increasing use of fibre reinforced plastic composites, due to their high specific mechanical properties. However, due to their brittleness, low velocity impact can cause delaminations beneath the surface, while the surface may appear to be undamaged upon visual inspection. Such damage is called barely visible impact damage (BVID). Such internal damages lead to significant reduction in local strengths and ultimately could lead to catastrophic failures. It is therefore important to detect and monitor damages in high loaded composite components to receive an early warning for a well timed maintenance of the aircraft. Non-linear ultrasonic spectroscopy methods are promising damage detection and material characterization tools. In this paper, two different non-linear elastic wave spectroscopy (NEWS) methods are presented: single mode nonlinear resonance ultrasound (NRUS) and nonlinear wave modulation technique (NWMS). The NEWS methods were applied to detect delamination damage due to low velocity impact (<12 J) on various composite plates. The results showed that the proposed methodology appear to be highly sensitive to the presence of damage with very promising future NDT and structural health monitoring applications.

An efficient and fast analytical procedure for the bromine determination in waste electrical and electronic equipment plastics.

PubMed

Taurino, R; Cannio, M; Mafredini, T; Pozzi, P

2014-01-01

In this study, X-ray fluorescence (XRF) spectroscopy was used, in combination with micro-Raman spectroscopy, for a fast determination of bromine concentration and then of brominated flame retardants (BFRs) compounds in waste electrical and electronic equipments. Different samples from different recycling industries were characterized to evaluate the sorting performances of treatment companies. This investigation must be considered of prime research interest since the impact of BFRs on the environment and their potential risk on human health is an actual concern. Indeed, the new European Restriction of Hazardous Substances Directive (RoHS 2011/65/EU) demands that plastics with BFRs concentration above 0.1%, being potential health hazards, are identified and eliminated from the recycling process. Our results show the capability and the potential of Raman spectroscopy, together with XRF analysis, as effective tools for the rapid detection of BFRs in plastic materials. In particular, the use of these two techniques in combination can be considered as a promising method suitable for quality control applications in the recycling industry.

Preparation of gold nanoparticles by microwave heating and application of spectroscopy to study conjugate of gold nanoparticles with antibody E. coli O157:H7

NASA Astrophysics Data System (ADS)

Thanh Ngo, Vo Ke; Phuong Uyen Nguyen, Hoang; Phat Huynh, Trong; Nguyen Pham Tran, Nguyen; Lam, Quang Vinh; Dat Huynh, Thanh

2015-09-01

Gold nanoparticles (AuNPs) of 15-20 nm size range have attracted attention for producing smart sensing devices as diagnostic tools in biomedical sciences. Citrate capped AuNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibodies. In this paper we describe a method for the low cost synthesis of gold nanoparticles using sodium citrate (Na3Ct) reduction in chloroauric acid (HAuCl4.3H2O) by microwave heating (diameter about 13-15 nm). Gold nanoparticles were functionalized with surface activation by 3-mercaptopropionic acid for attaching antibody. These nanoparticles were then reacted with anti-E. coli O157:H7, using N-hydroxy succinimide (NHS) and carbondimide hydrochloride (EDC) coupling chemistry. The product was characterized with UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta potential. In addition, the binding of antibody-gold nanoparticles conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy (TEM).

Active antioxidants in ex-vivo examination of burn wound healing by means of IR and Raman spectroscopies-Preliminary comparative research

NASA Astrophysics Data System (ADS)

Pielesz, Anna; Biniaś, Dorota; Sarna, Ewa; Bobiński, Rafał; Kawecki, Marek; Glik, Justyna; Klama-Baryła, Agnieszka; Kitala, Diana; Łabuś, Wojciech; Paluch, Jadwiga; Kraut, Małgorzata

2017-02-01

Being a complex traumatic event, burn injury also affects other organ systems apart from the skin. Wounds undergo various pathological changes which are accompanied by alterations in the molecular environment. Information about molecules may be obtained with the use of Raman spectroscopy and Fourier-transform infrared spectroscopy, and when combined, both methods are a powerful tool for providing material characterization. Alterations in the molecular environment may lead to identifying objective markers of acute wound healing. In general, incubation of samples in solutions of L-ascorbic acid and 5% and 7% orthosilicic acid organizes the collagen structure, whereas the increased intensity of the Raman bands in the region of 1500-800 cm- 1 reveals regeneration of the burn tissue. Since oxidative damage is one of the mechanisms responsible for local and distant pathophysiological events after burn, antioxidant therapy can prove to be beneficial in minimizing burn wounds, which was examined on the basis of human skin samples and chicken skin samples, the latter being subject to modification when heated to a temperature sufficient for the simulation of a burn incident.

Reducing uncertainties in energy dissipation measurements in atomic force spectroscopy of molecular networks and cell-adhesion studies.

PubMed

Biswas, Soma; Leitao, Samuel; Theillaud, Quentin; Erickson, Blake W; Fantner, Georg E

2018-06-20

Atomic force microscope (AFM) based single molecule force spectroscopy (SMFS) is a valuable tool in biophysics to investigate the ligand-receptor interactions, cell adhesion and cell mechanics. However, the force spectroscopy data analysis needs to be done carefully to extract the required quantitative parameters correctly. Especially the large number of molecules, commonly involved in complex networks formation; leads to very complicated force spectroscopy curves. One therefore, generally characterizes the total dissipated energy over a whole pulling cycle, as it is difficult to decompose the complex force curves into individual single molecule events. However, calculating the energy dissipation directly from the transformed force spectroscopy curves can lead to a significant over-estimation of the dissipated energy during a pulling experiment. The over-estimation of dissipated energy arises from the finite stiffness of the cantilever used for AFM based SMFS. Although this error can be significant, it is generally not compensated for. This can lead to significant misinterpretation of the energy dissipation (up to the order of 30%). In this paper, we show how in complex SMFS the excess dissipated energy caused by the stiffness of the cantilever can be identified and corrected using a high throughput algorithm. This algorithm is then applied to experimental results from molecular networks and cell-adhesion measurements to quantify the improvement in the estimation of the total energy dissipation.

Antibody-Unfolding and Metastable-State Binding in Force Spectroscopy and Recognition Imaging

PubMed Central

Kaur, Parminder; Qiang-Fu; Fuhrmann, Alexander; Ros, Robert; Kutner, Linda Obenauer; Schneeweis, Lumelle A.; Navoa, Ryman; Steger, Kirby; Xie, Lei; Yonan, Christopher; Abraham, Ralph; Grace, Michael J.; Lindsay, Stuart

2011-01-01

Force spectroscopy and recognition imaging are important techniques for characterizing and mapping molecular interactions. In both cases, an antibody is pulled away from its target in times that are much less than the normal residence time of the antibody on its target. The distribution of pulling lengths in force spectroscopy shows the development of additional peaks at high loading rates, indicating that part of the antibody frequently unfolds. This propensity to unfold is reversible, indicating that exposure to high loading rates induces a structural transition to a metastable state. Weakened interactions of the antibody in this metastable state could account for reduced specificity in recognition imaging where the loading rates are always high. The much weaker interaction between the partially unfolded antibody and target, while still specific (as shown by control experiments), results in unbinding on millisecond timescales, giving rise to rapid switching noise in the recognition images. At the lower loading rates used in force spectroscopy, we still find discrepancies between the binding kinetics determined by force spectroscopy and those determined by surface plasmon resonance—possibly a consequence of the short tethers used in recognition imaging. Recognition imaging is nonetheless a powerful tool for interpreting complex atomic force microscopy images, so long as specificity is calibrated in situ, and not inferred from equilibrium binding kinetics. PMID:21190677

Autofluorescence lifetime imaging during transoral robotic surgery: a clinical validation study of tumor detection (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lagarto, João. L.; Phipps, Jennifer E.; Unger, Jakob; Faller, Leta M.; Gorpas, Dimitris; Ma, Dinglong M.; Bec, Julien; Moore, Michael G.; Bewley, Arnaud F.; Yankelevich, Diego R.; Sorger, Jonathan M.; Farwell, Gregory D.; Marcu, Laura

2017-02-01

Autofluorescence lifetime spectroscopy is a promising non-invasive label-free tool for characterization of biological tissues and shows potential to report structural and biochemical alterations in tissue owing to pathological transformations. In particular, when combined with fiber-optic based instruments, autofluorescence lifetime measurements can enhance intraoperative diagnosis and provide guidance in surgical procedures. We investigate the potential of a fiber-optic based multi-spectral time-resolved fluorescence spectroscopy instrument to characterize the autofluorescence fingerprint associated with histologic, morphologic and metabolic changes in tissue that can provide real-time contrast between healthy and tumor regions in vivo and guide clinicians during resection of diseased areas during transoral robotic surgery. To provide immediate feedback to the surgeons, we employ tracking of an aiming beam that co-registers our point measurements with the robot camera images and allows visualization of the surgical area augmented with autofluorescence lifetime data in the surgeon's console in real-time. For each patient, autofluorescence lifetime measurements were acquired from normal, diseased and surgically altered tissue, both in vivo (pre- and post-resection) and ex vivo. Initial results indicate tumor and normal regions can be distinguished based on changes in lifetime parameters measured in vivo, when the tumor is located superficially. In particular, results show that autofluorescence lifetime of tumor is shorter than that of normal tissue (p < 0.05, n = 3). If clinical diagnostic efficacy is demonstrated throughout this on-going study, we believe that this method has the potential to become a valuable tool for real-time intraoperative diagnosis and guidance during transoral robot assisted cancer removal interventions.

Dental caries detection by optical spectroscopy: a polarized Raman approach with fibre-optic coupling

NASA Astrophysics Data System (ADS)

Ko, A. C.-T.; Choo-Smith, L.-P.; Werner, J.; Hewko, M.; Sowa, M. G.; Dong, C.; Cleghorn, B.

2006-09-01

Incipient dental caries lesions appear as white spots on the tooth surface; however, accurate detection of early approximal lesions is difficult due to limited sensitivity of dental radiography and other traditional diagnostic tools. A new fibre-optic coupled spectroscopic method based on polarized Raman spectroscopy (P-RS) with near-IR laser excitation is introduced which provides contrast for detecting and characterizing incipient caries. Changes in polarized Raman spectra are observed in PO 4 3- vibrations arising from hydroxyapatite of mineralized tooth tissue. Demineralization-induced morphological/orientational alteration of enamel crystallites is believed to be responsible for the reduction of Raman polarization anisotropy observed in the polarized Raman spectra of caries lesions. Supporting evidence obtained by polarized Raman spectral imaging is presented. A specially designed fibre-optic coupled setup for simultaneous measurement of parallel- and cross-polarized tooth Raman spectra is demonstrated in this study.

The CAnadian NIRISS Unbiased Cluster Survey (CANUCS)

NASA Astrophysics Data System (ADS)

Ravindranath, Swara; NIRISS GTO Team

2017-06-01

CANUCS GTO program is a JWST spectroscopy and imaging survey of five massive galaxy clusters and ten parallel fields using the NIRISS low-resolution grisms, NIRCam imaging and NIRSpec multi-object spectroscopy. The primary goal is to understand the evolution of low mass galaxies across cosmic time. The resolved emission line maps and line ratios for many galaxies, with some at resolution of 100pc via the magnification by gravitational lensing will enable determining the spatial distribution of star formation, dust and metals. Other science goals include the detection and characterization of galaxies within the reionization epoch, using multiply-imaged lensed galaxies to constrain cluster mass distributions and dark matter substructure, and understanding star-formation suppression in the most massive galaxy clusters. In this talk I will describe the science goals of the CANUCS program. The proposed prime and parallel observations will be presented with details of the implementation of the observation strategy using JWST proposal planning tools.

Probing plasmons in three dimensions by combining complementary spectroscopies in a scanning transmission electron microscope

DOE PAGES

Hachtel, Jordan A.; Marvinney, Claire; Mouti, Anas; ...

2016-03-02

The nanoscale optical response of surface plasmons in three-dimensional metallic nanostructures plays an important role in many nanotechnology applications, where precise spatial and spectral characteristics of plasmonic elements control device performance. Electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) within a scanning transmission electron microscope have proven to be valuable tools for studying plasmonics at the nanoscale. Each technique has been used separately, producing three-dimensional reconstructions through tomography, often aided by simulations for complete characterization. Here we demonstrate that the complementary nature of the two techniques, namely that EELS probes beam-induced electronic excitations while CL probes radiative decay, allows usmore » to directly obtain a spatially- and spectrally-resolved picture of the plasmonic characteristics of nanostructures in three dimensions. Furthermore, the approach enables nanoparticle-by-nanoparticle plasmonic analysis in three dimensions to aid in the design of diverse nanoplasmonic applications.« less

Analysis of fresco by laser induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Caneve, L.; Diamanti, A.; Grimaldi, F.; Palleschi, G.; Spizzichino, V.; Valentini, F.

2010-08-01

The laser-based techniques have been shown to be a very powerful tool for artworks characterization and are used in the field of cultural heritage for the offered advantages of minimum invasiveness, in situ applicability and high sensitivity. Laser induced breakdown spectroscopy, in particular, has been applied in this field to many different kinds of ancient materials with successful results. In this work, a fragment of a Roman wall painting from the archaeological area of Pompeii has been investigated by LIBS. The sample elemental composition resulting from LIBS measurements suggested the presence of certain pigments. The ratio of the intensities of different lines related to some characteristic elements is proposed as an indicator for pigment recognition. The depth profiling permitted to put in evidence the presence of successive paint layers with different compositions. A comparison with the results obtained by the microscopy inspection of the sample has been done.

Near-infrared autofluorescence spectroscopy of in vivo soft tissue sarcomas

PubMed Central

Nguyen, John Quan; Gowani, Zain; O'Connor, Maggie; Pence, Isaac; Nguyen, The-Quyen; Holt, Ginger; Mahadevan-Jansen, Anita

2016-01-01

Soft tissue sarcomas (STS) are a rare and heterogeneous group of malignant tumors that are often treated via surgical resection. Inadequate resection can lead to local recurrence and decreased survival rates. In this study, we investigate the hypothesis that near-infrared (NIR) autofluorescence can be utilized for tumor margin analysis by differentiating STS from the surrounding normal tissue. Intraoperative in vivo measurements were acquired from 30 patients undergoing STS resection and were characterized to differentiate between normal tissue and STS. Overall, normal muscle and fat were observed to have the highest and lowest autofluorescence intensities, respectively, with STS falling in between. With the exclusion of well-differentiated liposarcomas, the algorithm's accuracy for classifying muscle, fat, and STS was 93%, 92%, and 88%, respectively. These findings suggest that NIR autofluorescence spectroscopy has potential as a rapid and nondestructive surgical guidance tool that can inform surgeons of suspicious margins in need of immediate re-excision. PMID:26625035

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

Parkin, William M.; Balan, Adrian; Liang, Liangbo

Here, we report how the presence of electron-beam-induced sulfur vacancies affects first-order Raman modes and correlate the effects with the evolution of the in situ transmission-electron microscopy (TEM) two-terminal conductivity of monolayer MoS 2 under electron irradiation. We observe a redshift in the E Raman peak and a less pronounced blueshift in the A' 1 peak with increasing electron dose. Using energy-dispersive X-ray spectroscopy (EDS), we show that irradiation causes partial removal of sulfur and correlate the dependence of the Raman peak shifts with S vacancy density (a few %), which is confirmed by first-principles density functional theory calculations. Inmore » situ device current measurements show exponential decrease in channel current upon irradiation. Our analysis demonstrates that the observed frequency shifts are intrinsic properties of the defective systems and that Raman spectroscopy can be used as a quantitative diagnostic tool to characterize MoS 2-based transport channels.« less

Laser writing of single-crystalline gold substrates for surface enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

2017-07-01

Surface enhanced Raman scattering (SERS) spectroscopy, a powerful contemporary tool for studying low-concentration analytes via surface plasmon induced enhancement of local electric field, is of utility in biochemistry, material science, threat detection, and environmental studies. We have developed a simple, fast, scalable, and relatively low-cost optical method of fabricating and characterizing large-area, reusable and broadband SERS substrates with long storage lifetime. We use tightly focused, intense infra-red laser pulses to write gratings on single-crystalline, Au (1 1 1) gold films on mica which act as SERS substrates. Our single-crystalline SERS substrates compare favourably, in terms of surface quality and roughness, to those fabricated in poly-crystalline Au films. Tests show that our SERS substrates have the potential of detecting urea and 1,10-phenantroline adulterants in milk and water, respectively, at 0.01 ppm (or lower) concentrations.

In vitro and in vivo anti-inflammatory properties of green synthesized silver nanoparticles using Viburnum opulus L. fruits extract.

PubMed

Moldovan, Bianca; David, Luminita; Vulcu, Adriana; Olenic, Liliana; Perde-Schrepler, Maria; Fischer-Fodor, Eva; Baldea, Ioana; Clichici, Simona; Filip, Gabriela Adriana

2017-10-01

A green, rapid and cost effective method for the bio-synthesis of silver nanoparticles (AgNPs), using polyphenols present in European cranberry bush fruit extracts was developed. The obtained AgNPs were characterized by ultra-violet visible spectroscopy (UV-VIS), Fourier transform - infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and X-ray diffraction patterns (XRD). The average size of the spherical AgNPs was found to be 25nm. The anti-inflammatory effect of the biomaterials was investigated, both in vitro (on HaCaT cell line, exposed to UVB radiation) and in vivo (on acute inflammation model in Wistar rats). Our results support the conclusion that the photosynthesized silver nanoparticles present a potent anti-inflammatory activity and could be successfully used as therapeutic tools for treatment of inflammation. Copyright © 2017 Elsevier B.V. All rights reserved.

Lifetime fluorescence spectroscopy for in situ investigation of osteogenic differentiation

NASA Astrophysics Data System (ADS)

Marcu, Laura; Elbarbary, Amir; Zuk, Patricia; De Ugarte, Daniel A.; Benhaim, Prosper; Kurt, Hamza; Hedrick, Marc H.; Ashjian, Peter

2003-07-01

Time-Resolved Laser-Induced Fluorescence Spectroscopy (TR-LIFS) represents a potential tool for the in-situ characterization of bioengineered tissues. In this study, we evaluate the application of TR-LIFS to non-intrusive monitoring of matrix composition during osteogenetic differentiation. Human adipose-derived stem cells, harvested from 3 patients, were induced in osteogenic media for 3, 5, and 7 weeks. Samples were subsequently collected and probed for time-resolved fluorescence emission with a pulsed nitrogen laser. Fluorescence parameters, derived from both spectral- and time-domain, were used for sample characterization. The samples were further analyzed using Western blot analysis and computer-based densitometry. A significant change in the fluorescence parameters was detected for samples beyond 3 weeks of osteogenic differentiation. The spectroscopic observations: 1) show increase of collagen I when contrasted against the time-resolved fluorescence spectra of commercially available collagens; and 2) are in agreement with Western blot analysis that demonstrated significant increase in collagen I content between 3- vs. 5-weeks and 3- vs. 7-weeks and no changes for collagens III, IV, and V. Our results suggest that TR-LIFS can be used as a non-invasive means for the detection of specific collagens in maturing connective tissues.

Optical spectroscopy combined with high-resolution magnetic resonance imaging for digestive wall assessment: endoluminal bimodal probe conception and characterization in vitro, on organic sample and in vivo on a rabbit

NASA Astrophysics Data System (ADS)

Ramgolam, Anoop; Sablong, Raphaël; Lafarge, Lionel; Saint-Jalmes, Hervé; Beuf, Olivier

2011-11-01

Colorectal cancer is a major health issue worldwide. Conventional white light endoscopy (WLE) coupled to histology is considered as the gold standard today and is the most widespread technique used for colorectal cancer diagnosis. However, during the early stages, colorectal cancer is very often characterized by flat adenomas which develop just underneath the mucosal surface. The use of WLE, which is heavily based on the detection of morphological changes, becomes quite delicate due to subtle or quasi-invisible morphological changes of the colonic lining. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where high spatial resolution MRI is combined with autofluorescence and reflectance spectroscopy in a bimodal endoluminal probe to extract morphological data and biochemical information, respectively. The design and conception of the endoluminal probe are detailed and the promising preliminary results obtained in vitro (home-built phantom containing eosin and rhodamine B), on an organic sample (the kiwi fruit) and in vivo on a rabbit are presented and discussed.

Magnetization Dynamics of Amorphous Ribbons and Wires Studied by Inductance Spectroscopy

PubMed Central

Betancourt, Israel

2010-01-01

Inductance spectroscopy is a particular formulation variant of the well known complex impedance formalism typically used for the electric characterization of dielectric, ferroelectric, and piezoelectric materials. It has been successfully exploited as a versatile tool for characterization of the magnetization dynamics in amorphous ribbons and wires by means of simple experiments involving coils for sample holding and impedance analyzer equipment. This technique affords the resolution of the magnetization processes in soft magnetic materials, in terms of reversible deformation of pinned domain walls, domain wall displacements and spin rotation, for which characteristic parameters such as the alloy initial permeability and the relaxation frequencies, indicating the dispersion of each process, can be defined. Additionally, these parameters can be correlated with chemical composition variation, size effects and induced anisotropies, leading to a more physical insight for the understanding of the frequency dependent magnetic response of amorphous alloys, which is of prime interest for the development of novel applications in the field of telecommunication and sensing technologies. In this work, a brief overview, together with recent progress on the magnetization dynamics of amorphous ribbons, wires, microwires and biphase wires, is presented and discussed for the intermediate frequency interval between 10 Hz and 13 MHz. PMID:28879975

Characterization and calibration of a combined laser Raman, fluorescence and coherent Raman spectrometer

NASA Astrophysics Data System (ADS)

Lawhead, Carlos; Cooper, Nathan; Anderson, Josiah; Shiver, Tegan; Ujj, Laszlo

2014-03-01

Electronic and vibrational spectroscopy is extremely important tools used in material characterization; therefore a table-top laser spectrometer system was built in the spectroscopy lab at the UWF physics department. The system is based upon an injection seeded nanosecond Nd:YAG Laser. The second and the third harmonics of the fundamental 1064 nm radiation are used to generate Raman and fluorescence spectra measured with MS260i imaging spectrograph occupied with a CCD detector and cooled to -85 °C, in order to minimize the dark background noise. The wavelength calibration was performed with the emission spectra of standard gas-discharge lamps. Spectral sensitivity calibration is needed before any spectra are recorded, because of the table-top nature of the instrument. A variety of intensity standards were investigated to find standards suitable for our table top setup that do not change the geometry of the system. High quality measurement of Raman standards where analyzed to test spectral corrections. Background fluorescence removal methods were used to improve Raman signal intensity reading on highly fluorescent molecules. This instrument will be used to measure vibrational and electronic spectra of biological molecules.

Exploratory investigations of hypervelocity intact capture spectroscopy

NASA Technical Reports Server (NTRS)

Tsou, P.; Griffiths, D. J.

1993-01-01

The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

Two-dimensional NMR spectroscopy as a tool to link soil organic matter composition to ecosystem processes

NASA Astrophysics Data System (ADS)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Schleucher, Jürgen

2014-05-01

Environmental factors (e.g. temperature and moisture) and the size and composition of soil microbial populations are often considered the main drivers of soil organic matter (SOM) mineralization. Less consideration is given to the role of SOM as a substrate for microbial metabolism and the importance of the organo-chemical composition of SOM on decomposition. In addition, a fraction of the SOM is often considered as recalcitrant to mineralization leading to accumulation of SOM. However, recently the concept of intrinsic recalcitrance of SOM to mineralization has been questioned. The challenge in investigating the role of SOM composition on its mineralization to a large extent stems from the difficulties in obtaining high resolution characterization of a very complex matrix. 13C nuclear magnetic resonance (NMR) spectroscopy is a widely used tool to characterize SOM. However, SOM is a very complex mixture and in the resulting 13C NMR spectra, the identified functional groups may represent different molecular fragments that appear in the same spectral region leading to broad peaks. These overlaps defy attempts to identify molecular moieties, and this makes it impossible to derive information at a resolution needed for evaluating e.g. recalcitrance of SOM. Here we applied a method, developed in wood science for the pulp paper industry, to achieve a better characterization of SOM. We directly dissolved finely ground organic layers of boreal forest floors-litters, fibric and humic horizons of both coniferous and broadleaved stands-in dimethyl sulfoxide and analyzed the resulting solution with a two-dimensional (2D) 1H-13C NMR experiment. We will discuss methodological aspects related to the ability to identify and quantify individual molecular moieties in SOM. We will demonstrate how the spectra resolve signals of CH groups in a 2D plane determined by the 13C and 1H chemical shifts, thereby vastly increasing the resolving power and information content of NMR spectra. The obtained 2D spectra resolve overlaps observed in 1D 13C spectra, so that hundreds of distinct CH moieties can be observed and many individual molecular fragments can be identified. For instance, in the aromatic spectral region, signals originating from various lignin monomers and unsaturated compounds can be resolved. This yields a detailed chemical fingerprint of the SOM samples, and valuable insights on molecular structures. We observed differences in the respective aromatic region of the 2D spectra of the litter layers and the fibric and humic horizons, in relation with humification processes. We were also able to relate the cross-peak complexity and abundance patterns of identifiable molecular moieties to variability in the temperature response of organic matter degradation, as assessed by Q10. To conclude, solution-state 2D NMR spectroscopy is a highly promising new tool to characterize SOM composition at the molecular level, which opens completely new possibilities to link SOM molecular composition to ecosystem processes, and their responses to environmental changes.

Online and Certifiable Spectroscopy Courses Using Information and Communication Tools. a Model for Classrooms and Beyond

NASA Astrophysics Data System (ADS)

Krishnan, Mangala Sunder

2015-06-01

Online education tools and flipped (reverse) class models for teaching and learning and pedagogic and andragogic approaches to self-learning have become quite mature in the last few years because of the revolution in video, interactive software and social learning tools. Open Educational resources of dependable quality and variety are also becoming available throughout the world making the current era truly a renaissance period for higher education using Internet. In my presentation, I shall highlight structured course content preparation online in several areas of spectroscopy and also the design and development of virtual lab tools and kits for studying optical spectroscopy. Both elementary and advanced courses on molecular spectroscopy are currently under development jointly with researchers in other institutions in India. I would like to explore participation from teachers throughout the world in the teaching-learning process using flipped class methods for topics such as experimental and theoretical microwave spectroscopy of semi-rigid and non-rigid molecules, molecular complexes and aggregates. In addition, courses in Raman, Infrared spectroscopy experimentation and advanced electronic spectroscopy courses are also envisaged for free, online access. The National Programme on Technology Enhanced Learning (NPTEL) and the National Mission on Education through Information and Communication Technology (NMEICT) are two large Government of India funded initiatives for producing certified and self-learning courses with financial support for moderated discussion forums. The learning tools and interactive presentations so developed can be used in classrooms throughout the world using flipped mode of teaching. They are very much sought after by learners and researchers who are in other areas of learning but want to contribute to research and development through inter-disciplinary learning. NPTEL is currently is experimenting with Massive Open Online Course (MOOC) strategy, but with proctored and certified examination processes for large numbers in some of the above courses. I would like to present a summary of developments in these areas to help focus classroom (online and offline) learning of Molecular spectroscopy.

Advanced MRI in Multiple Sclerosis: Current Status and Future Challenges

PubMed Central

Fox, Robert J.; Beall, Erik; Bhattacharyya, Pallab; Chen, Jacqueline; Sakaie, Ken

2011-01-01

Synopsis Magnetic resonance imaging (MRI) has rapidly become a leading research tool in the study of multiple sclerosis (MS). Conventional imaging is useful in diagnosis and management of the inflammatory stages of MS, but has limitations in describing the degree of tissue injury as well as the cause of progressive disability seen in the later stages of disease. Advanced MRI techniques hold promise to fill this void. Magnetization transfer imaging is a widely available technique that can characterize demyelination and may be useful in measuring putative remyelinating therapies. Diffusion tensor imaging describes the three-dimensional diffusion of water and holds promise in characterizing neurodegeneration and putative neuroprotective therapies. Spectroscopy measures the imbalance of cellular metabolites and could help unravel the pathogenesis of neurodegeneration in MS. Functional (f) MRI can be used to understand the functional consequences of MS injury, including the impact on cortical function and compensatory mechanisms. These imaging tools hold great promise to increase our understanding of MS pathogenesis and provide greater insight into the efficacy of new MS therapies. PMID:21439446

Probing the Complexities of Structural Changes in Layered Oxide Cathode Materials for Li-Ion Batteries during Fast Charge-Discharge Cycling and Heating.

PubMed

Hu, Enyuan; Wang, Xuelong; Yu, Xiqian; Yang, Xiao-Qing

2018-02-20

The rechargeable lithium-ion battery (LIB) is the most promising energy storage system to power electric vehicles with high energy density and long cycling life. However, in order to meet customers' demands for fast charging, the power performances of current LIBs need to be improved. From the cathode aspect, layer-structured cathode materials are widely used in today's market and will continue to play important roles in the near future. The high rate capability of layered cathode materials during charging and discharging is critical to the power performance of the whole cell and the thermal stability is closely related to the safety issues. Therefore, the in-depth understanding of structural changes of layered cathode materials during high rate charging/discharging and the thermal stability during heating are essential in developing new materials and improving current materials. Since structural changes take place from the atomic level to the whole electrode level, combination of characterization techniques covering multilength scales is quite important. In many cases, this means using comprehensive tools involving diffraction, spectroscopy, and imaging to differentiate the surface from the bulk and to obtain structural/chemical information with different levels of spatial resolution. For example, hard X-ray spectroscopy can yield the bulk information and soft X-ray spectroscopy can give the surface information; X-ray based imaging techniques can obtain spatial resolution of tens of nanometers, and electron-based microcopy can go to angstroms. In addition to challenges associated with different spatial resolution, the dynamic nature of structural changes during high rate cycling and heating requires characterization tools to have the capability of collecting high quality data in a time-resolved fashion. Thanks to the advancement in synchrotron based techniques and high-resolution electron microscopy, high temporal and spatial resolutions can now be achieved. In this Account, we focus on the recent works studying kinetic and thermal properties of layer-structured cathode materials, especially the structural changes during high rate cycling and the thermal stability during heating. Advanced characterization techniques relating to the rate capability and thermal stability will be introduced. The different structure evolution behavior of cathode materials cycled at high rate will be compared with that cycled at low rate. Different response of individual transition metals and the inhomogeneity in chemical distribution will be discussed. For the thermal stability, the relationship between structural changes and oxygen release will be emphatically pointed out. In all these studies being reviewed, advanced characterization techniques are critically applied to reveal complexities at multiscale in layer-structured cathode materials.

Lithology and mineralogy recognition from geochemical logging tool data using multivariate statistical analysis.

PubMed

Konaté, Ahmed Amara; Ma, Huolin; Pan, Heping; Qin, Zhen; Ahmed, Hafizullah Abba; Dembele, N'dji Dit Jacques

2017-10-01

The availability of a deep well that penetrates deep into the Ultra High Pressure (UHP) metamorphic rocks is unusual and consequently offers a unique chance to study the metamorphic rocks. One such borehole is located in the southern part of Donghai County in the Sulu UHP metamorphic belt of Eastern China, from the Chinese Continental Scientific Drilling Main hole. This study reports the results obtained from the analysis of oxide log data. A geochemical logging tool provides in situ, gamma ray spectroscopy measurements of major and trace elements in the borehole. Dry weight percent oxide concentration logs obtained for this study were SiO 2 , K 2 O, TiO 2 , H 2 O, CO 2 , Na 2 O, Fe 2 O 3 , FeO, CaO, MnO, MgO, P 2 O 5 and Al 2 O 3 . Cross plot and Principal Component Analysis methods were applied for lithology characterization and mineralogy description respectively. Cross plot analysis allows lithological variations to be characterized. Principal Component Analysis shows that the oxide logs can be summarized by two components related to the feldspar and hydrous minerals. This study has shown that geochemical logging tool data is accurate and adequate to be tremendously useful in UHP metamorphic rocks analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of photoacoustic mid-infrared spectroscopy to characterize soil properties and soil organic matter stability

NASA Astrophysics Data System (ADS)

Peltre, Clement; Bruun, Sander; Du, Changwen; Stoumann Jensen, Lars

2014-05-01

The persistence of soil organic matter (SOM) is recognized as a major ecosystem property due to its key role in earth carbon cycling, soil quality and ecosystem services. SOM stability is typically studied using biological methods such as measuring CO2-C evolution from microbial decomposition of SOM during laboratory incubation or by physical or chemical fractionation methods, allowing the separation of a labile fraction of SOM. However these methods are time consuming and there is still a need for developing reliable techniques to characterize SOM stability, providing both quantitative measurements and qualitative information, in order to improve our understanding of the mechanisms controlling SOM persistence. Several spectroscopic techniques have been used to characterize and predict SOM stability, such as near infrared reflectance spectroscopy (NIRS) and diffuse reflectance mid-infrared spectroscopy (DRIFT). The latter allows a proper identification of spectral regions corresponding to vibrations of specific molecular or functional groups associated with SOM lability. However, reflectance spectroscopy for soil analyses raises some difficulties related to the low reflectance of soils, and to the high influence of particle size. In the last three decades, the progresses in microphone sensitivity dramatically increased the performance of photoacoustic Fourier transform mid-infrared spectroscopy (FTIR-PAS). This technique offers benefits over reflectance spectroscopy techniques, because particle size and the level of sample reflectance have little effect of on the PAS signal, since FTIR-PAS is a direct absorption technique. Despite its high potential for soil analysis, only a limited number of studies have so far applied FTIR-PAS for soil characterization and its potential for determining SOM degradability still needs to be investigated. The objective of this study was to assess the potential of FTIR-PAS for the characterization of SOM decomposability during laboratory incubation and more classical soil parameters such as carbon and clay content for a range of 36 soils collected from various field experiments in Denmark. Partial least square (PLS) regression was used to correlate the collected FTIR-PAS spectra with the proportion of soil organic carbon mineralized after 34 weeks of incubation at 15° C and pF 2, taken as an indicator of the labile fraction of SOM. Results showed that it is possible to predict the labile fraction of SOM with FTIR PAS with similar accuracy as with NIRS (assessed in a previous study on the same soil set). FTIR-PAS offered the advantage over NIRS to allow identification of the chemical compounds positively or negatively correlated with the labile fraction of SOM. The band at 1612 cm-1 corresponding to polysaccharides, pectin and aromatic C=C was the band most positively correlated with labile SOM, which we attributed to the relative lability of fresh plant debris rich in polysaccharide and aromatic lignin. The band at 1560-1590 cm-1 assigned to N=H, C=N and aromatic C=C vibration was the band most negatively correlated with the labile fraction of SOM, confirming the abundance of nitrogenous and aromatic compounds in stabilized SOM. In conclusion, FTIR-PAS has proved to be a powerful tool to characterize the labile fraction of SOM, offering several benefits over reflectance spectroscopy techniques.

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.

Synthesis and characterization of a helicene-based imidazolium salt and its application in organic molecular electronics.

PubMed

Storch, Jan; Zadny, Jaroslav; Strasak, Tomas; Kubala, Martin; Sykora, Jan; Dusek, Michal; Cirkva, Vladimir; Matejka, Pavel; Krbal, Milos; Vacek, Jan

2015-02-02

Herein we demonstrate the synthesis of a helicene-based imidazolium salt. The salt was prepared by starting from racemic 2-methyl[6]helicene, which undergoes radical bromination to yield 2-(bromomethyl)[6]helicene. Subsequent treatment with 1-butylimidazole leads to the corresponding salt 1-butyl-3-(2-methyl[6]helicenyl)-imidazolium bromide. The prepared salt was subsequently characterized by using NMR spectroscopy and X-ray analysis, various optical spectrometric techniques, and computational chemistry tools. Finally, the imidazolium salt was immobilized onto a SiO2 substrate as a crystalline or amorphous deposit. The deposited layers were used for the development of organic molecular semiconductor devices and the construction of a fully reversible humidity sensor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vibrational spectroscopy for imaging single microbial cells in complex biological samples

DOE PAGES

Harrison, Jesse P.; Berry, David

2017-04-13

Here, vibrational spectroscopy is increasingly used for the rapid and non-destructive imaging of environmental and medical samples. Both Raman and Fourier-transform infrared (FT-IR) imaging have been applied to obtain detailed information on the chemical composition of biological materials, ranging from single microbial cells to tissues. Due to its compatibility with methods such as stable isotope labeling for the monitoring of cellular activities, vibrational spectroscopy also holds considerable power as a tool in microbial ecology. Chemical imaging of undisturbed biological systems (such as live cells in their native habitats) presents unique challenges due to the physical and chemical complexity of themore » samples, potential for spectral interference, and frequent need for real-time measurements. This Mini Review provides a critical synthesis of recent applications of Raman and FT-IR spectroscopy for characterizing complex biological samples, with a focus on developments in single-cell imaging. We also discuss how new spectroscopic methods could be used to overcome current limitations of singlecell analyses. Given the inherent complementarity of Raman and FT-IR spectroscopic methods, we discuss how combining these approaches could enable us to obtain new insights into biological activities either in situ or under conditions that simulate selected properties of the natural environment.« less

Vibrational spectroscopy for imaging single microbial cells in complex biological samples

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

Harrison, Jesse P.; Berry, David

Here, vibrational spectroscopy is increasingly used for the rapid and non-destructive imaging of environmental and medical samples. Both Raman and Fourier-transform infrared (FT-IR) imaging have been applied to obtain detailed information on the chemical composition of biological materials, ranging from single microbial cells to tissues. Due to its compatibility with methods such as stable isotope labeling for the monitoring of cellular activities, vibrational spectroscopy also holds considerable power as a tool in microbial ecology. Chemical imaging of undisturbed biological systems (such as live cells in their native habitats) presents unique challenges due to the physical and chemical complexity of themore » samples, potential for spectral interference, and frequent need for real-time measurements. This Mini Review provides a critical synthesis of recent applications of Raman and FT-IR spectroscopy for characterizing complex biological samples, with a focus on developments in single-cell imaging. We also discuss how new spectroscopic methods could be used to overcome current limitations of singlecell analyses. Given the inherent complementarity of Raman and FT-IR spectroscopic methods, we discuss how combining these approaches could enable us to obtain new insights into biological activities either in situ or under conditions that simulate selected properties of the natural environment.« less

Single-step biosynthesis and characterization of silver nanoparticles using Zornia diphylla leaves: A potent eco-friendly tool against malaria and arbovirus vectors.

PubMed

Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan; Hoti, S L; Khater, Hanem F; Benelli, Giovanni

2016-08-01

Mosquitoes (Diptera: Culicidae) are vectors of important pathogens and parasites, including malaria, dengue, chikungunya, Japanese encephalitis, lymphatic filariasis and Zika virus. The application of synthetic insecticides causes development of resistance, biological magnification of toxic substances through the food chain, and adverse effects on the environment and human health. In this scenario, eco-friendly control tools of mosquito vectors are a priority. Here single-step fabrication of silver nanoparticles (AgNP) using a cheap aqueous leaf extract of Zornia diphylla as reducing and capping agent pf Ag(+) ions has been carried out. Biosynthesized AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of Z. diphylla leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the Z. diphylla leaf extract and Ag NP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized Ag NP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 12.53, 13.42 and 14.61μg/ml, respectively. Biosynthesized Ag NP were found safer to non-target organisms Chironomus circumdatus, Anisops bouvieri and Gambusia affinis, with the respective LC50 values ranging from 613.11 to 6903.93μg/ml, if compared to target mosquitoes. Overall, our results highlight that Z. diphylla-fabricated Ag NP are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target organisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Towards nanometric resolution in multilayer depth profiling: a comparative study of RBS, SIMS, XPS and GDOES.

PubMed

Escobar Galindo, Ramón; Gago, Raul; Duday, David; Palacio, Carlos

2010-04-01

An increasing amount of effort is currently being directed towards the development of new functionalized nanostructured materials (i.e., multilayers and nanocomposites). Using an appropriate combination of composition and microstructure, it is possible to optimize and tailor the final properties of the material to its final application. The analytical characterization of these new complex nanostructures requires high-resolution analytical techniques that are able to provide information about surface and depth composition at the nanometric level. In this work, we comparatively review the state of the art in four different depth-profiling characterization techniques: Rutherford backscattering spectroscopy (RBS), secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectroscopy (GDOES). In addition, we predict future trends in these techniques regarding improvements in their depth resolutions. Subnanometric resolution can now be achieved in RBS using magnetic spectrometry systems. In SIMS, the use of rotating sample holders and oxygen flooding during analysis as well as the optimization of floating low-energy ion guns to lower the impact energy of the primary ions improves the depth resolution of the technique. Angle-resolved XPS provides a very powerful and nondestructive technique for obtaining depth profiling and chemical information within the range of a few monolayers. Finally, the application of mathematical tools (deconvolution algorithms and a depth-profiling model), pulsed sources and surface plasma cleaning procedures is expected to greatly improve GDOES depth resolution.

FT-IR spectroscopy as a tool for rapid identification and intra-species characterization of airborne filamentous fungi.

PubMed

Fischer, Guido; Braun, Silvia; Thissen, Ralf; Dott, Wolfgang

2006-01-01

Identification of microfungi is time-consuming due to cultivation and microscopic examination and can be influenced by the interpretation of the macro- and micro-morphological characters observed. Fungal conidia contain mycotoxins that may be present in bioaerosols and thus the capacity for production of mycotoxins (and allergens) needs to be investigated to create a basis for reliable risk assessment in environmental and occupational hygiene. The present investigation aimed to create a simple but sophisticated method for the preparation of samples and the identification of airborne fungi by FT-IR spectroscopy. The method was suited to reproducibly differentiate Aspergillus and Penicillium species on the generic, the species, and the strain level. There are strong indications that strains of one taxon differing in metabolite production can be reliably distinguished by FT-IR spectroscopy (e.g. Aspergillus parasiticus). On the other hand, species from different taxa being similar in secondary metabolite production showed comparably higher similarities. The results obtained here can serve as a basis for the development of a database for species identification and strain characterization of microfungi. The method presented here will improve and facilitate the risk assessment in case of bioaerosol exposure, as strains with different physiological properties (e.g. toxic, non-toxic) could be differentiated. Moreover, it has the potential to significantly improve the identification of microfungi in various fields of applied microbiological research, e.g. high throughput screening in view of specific physiological properties, biodiversity studies, inventories in environmental microbiology, and quality control measures.

Optical diagnostic techniques in tribological analysis: Applications to wear film characterization, solid lubricant chemical transition, and electrical sliding contacts

NASA Astrophysics Data System (ADS)

Windom, Bret C.

Friction and wear have undisputedly huge macroscopic effects on the cost and lifetime of many mechanical systems. The cost to replace parts and the cost to overcome the energy losses associated with friction, although small in nature, can be enormous over long operating times. The understanding of wear and friction begins with the understanding of the physics and chemistry between the reacting surfaces on a microscopic level. Light as a diagnostic tool is a good candidate to perform the very sensitive microscopic measurements needed to help understand the fundamental science occurring in friction/wear systems. Light's small length scales provide the capabilities to characterize very local surface phenomena, including thin transfer films and surface chemical transitions. Light-based diagnostic techniques provide nearly instantaneous results, enabling one to make in situ/real time measurements which could be used to track wear events and associated chemical kinetics. In the present study, two optical diagnostic techniques were investigated for the analysis of tribological systems. The first technique employed was Raman spectroscopy. Raman spectroscopy was investigated as a possible means for in situ measurement of thin transfer films in order to track the wear kinetics and structural transitions of bulk polymers. A micro-Raman system was designed, built, and characterized to track fresh wear films created from a pin-on-disk tribometer. The system proved capable of characterizing and tracking wear film thicknesses of ˜2 mum and greater. In addition, the system provided results indicating structural changes in the wear film as compared to the bulk when sliding speeds were increased. The spectral changes due to the altering of molecular vibrations can be attributed to the increase in temperature during high sliding speeds. Raman spectroscopy was also used to characterize the oxidation of molybdenum disulphide, a solid lubricant used in many applications, including high vacuum sliding. Resonance Raman effects were observed when an excitation wavelength of 632.8 nm was used. Raman spectroscopy was carried out on amorphous MoS2 while its temperature was increased to track the thermally induced oxidation of the MoS2 surface. In addition, other forms of MoS2 were investigated through Raman spectroscopy in which key distinctions between spectra were made. The second technique employed was atomic emission spectroscopy (AES) used to measure constituent species present in arcs created during electrical sliding contacts. Spectra indicated the presence of copper and zinc in the arcs created between copper fiber bundled brushes and a copper rotor. Atomic emission was used to measure the arc duration with a photo-multiplier tube (PMT) while the collected spectra were processed to assess arc temperature. The results suggest arcing in high-current electrical sliding contacts may be at least partially responsible for the high asymmetrical wear measured during tribology tests.

Characterizing pigments with hyperspectral imaging variable false-color composites

NASA Astrophysics Data System (ADS)

Hayem-Ghez, Anita; Ravaud, Elisabeth; Boust, Clotilde; Bastian, Gilles; Menu, Michel; Brodie-Linder, Nancy

2015-11-01

Hyperspectral imaging has been used for pigment characterization on paintings for the last 10 years. It is a noninvasive technique, which mixes the power of spectrophotometry and that of imaging technologies. We have access to a visible and near-infrared hyperspectral camera, ranging from 400 to 1000 nm in 80-160 spectral bands. In order to treat the large amount of data that this imaging technique generates, one can use statistical tools such as principal component analysis (PCA). To conduct the characterization of pigments, researchers mostly use PCA, convex geometry algorithms and the comparison of resulting clusters to database spectra with a specific tolerance (like the Spectral Angle Mapper tool on the dedicated software ENVI). Our approach originates from false-color photography and aims at providing a simple tool to identify pigments thanks to imaging spectroscopy. It can be considered as a quick first analysis to see the principal pigments of a painting, before using a more complete multivariate statistical tool. We study pigment spectra, for each kind of hue (blue, green, red and yellow) to identify the wavelength maximizing spectral differences. The case of red pigments is most interesting because our methodology can discriminate the red pigments very well—even red lakes, which are always difficult to identify. As for the yellow and blue categories, it represents a good progress of IRFC photography for pigment discrimination. We apply our methodology to study the pigments on a painting by Eustache Le Sueur, a French painter of the seventeenth century. We compare the results to other noninvasive analysis like X-ray fluorescence and optical microscopy. Finally, we draw conclusions about the advantages and limits of the variable false-color image method using hyperspectral imaging.

Near-infrared spectroscopy as a complementary age grading and species identification tool for African malaria vectors

USDA-ARS?s Scientific Manuscript database

Near-infrared spectroscopy (NIRS) was recently applied to age-grade and differentiate laboratory reared Anopheles gambiae sensu strico and Anopheles arabiensis sibling species of Anopheles gambiae sensu lato. In this study, we report further on the accuracy of this tool in simultaneously estimating ...

Autofluorescence and diffuse reflectance patterns in cervical spectroscopy

NASA Astrophysics Data System (ADS)

Marin, Nena Maribel

Fluorescence and diffuse reflectance spectroscopy are two new optical technologies, which have shown promise to aid in the real time, non-invasive identification of cancers and precancers. Spectral patterns carry a fingerprint of scattering, absorption and fluorescence properties in tissue. Scattering, absorption and fluorescence in tissue are directly affected by biological features that are diagnostically significant, such as nuclear size, micro-vessel density, volume fraction of collagen fibers, tissue oxygenation and cell metabolism. Thus, analysis of spectral patterns can unlock a wealth of information directly related with the onset and progression of disease. Data from a Phase II clinical trial to assess the technical efficacy of fluorescence and diffuse reflectance spectroscopy acquired from 850 women at three clinical locations with two research grade optical devices is calibrated and analyzed. Tools to process and standardize spectra so that data from multiple spectrometers can be combined and analyzed are presented. Methodologies for calibration and quality assurance of optical systems are established to simplify design issues and ensure validity of data for future clinical trials. Empirically based algorithms, using multivariate statistical approaches are applied to spectra and evaluated as a clinical diagnostic tool. Physically based algorithms, using mathematical models of light propagation in tissue are presented. The presented mathematical model combines a diffusion theory in P3 approximation reflectance model and a 2-layer fluorescence model using exponential attenuation and diffusion theory. The resulting adjoint fluorescence and reflectance model extracts twelve optical properties characterizing fluorescence efficiency of cervical epithelium and stroma fluorophores, stromal hemoglobin and collagen absorption, oxygen saturation, and stromal scattering strength and shape. Validations with Monte Carlo simulations show that adjoint model extracted optical properties of the epithelium and the stroma can be estimated accurately. Adjoint model is applied to 926 clinical measurements from 503 patients. Mean values of extracted optical properties have demonstrated to characterize the biological changes associated with dysplastic progression. Finally, penalized logistic regression algorithms are applied to discriminate dysplastic stages in tissue based on extracted optical features. This work provides understandable and interpretable information regarding predictive and generalization ability of optical spectroscopy in neoplastic changes using a minimum subset of optical measurements. Ultimately these methodologies would facilitate the transfer of these optical technologies into clinical practice.

Terahertz spectroscopic analysis of crystal orientation in polymers

NASA Astrophysics Data System (ADS)

Azeyanagi, Chisato; Kaneko, Takuya; Ohki, Yoshimichi

2018-05-01

Terahertz time-domain spectroscopy (THz-TDS) is attracting keen attention as a new spectroscopic tool for characterizing various materials. In this research, the possibility of analyzing the crystal orientation in a crystalline polymer by THz-TDS is investigated by measuring angle-resolved THz absorption spectra for sheets of poly(ethylene terephthalate), poly(ethylene naphthalate), and poly(phenylene sulfide). The resultant angle dependence of the absorption intensity of each polymer is similar to that of the crystal orientation examined using pole figures of X-ray diffraction. More specifically, THz-TDS can indicate the alignment of molecules in polymers.

In situ monitoring of cocrystals in formulation development using low-frequency Raman spectroscopy.

PubMed

Otaki, Takashi; Tanabe, Yuta; Kojima, Takashi; Miura, Masaru; Ikeda, Yukihiro; Koide, Tatsuo; Fukami, Toshiro

2018-05-05

In recent years, to guarantee a quality-by-design approach to the development of pharmaceutical products, it is important to identify properties of raw materials and excipients in order to determine critical process parameters and critical quality attributes. Feedback obtained from real-time analyses using various process analytical technology (PAT) tools has been actively investigated. In this study, in situ monitoring using low-frequency (LF) Raman spectroscopy (10-200 cm -1 ), which may have higher discriminative ability among polymorphs than near-infrared spectroscopy and conventional Raman spectroscopy (200-1800 cm -1 ), was investigated as a possible application to PAT. This is because LF-Raman spectroscopy obtains information about intermolecular and/or lattice vibrations in the solid state. The monitoring results obtained from Furosemide/Nicotinamide cocrystal indicate that LF-Raman spectroscopy is applicable to in situ monitoring of suspension and fluidized bed granulation processes, and is an effective technique as a PAT tool to detect the conversion risk of cocrystals. LF-Raman spectroscopy is also used as a PAT tool to monitor reactions, crystallizations, and manufacturing processes of drug substances and products. In addition, a sequence of conversion behaviors of Furosemide/Nicotinamide cocrystals was determined by performing in situ monitoring for the first time. Copyright © 2018 Elsevier B.V. All rights reserved.

SpectraFox: A free open-source data management and analysis tool for scanning probe microscopy and spectroscopy

NASA Astrophysics Data System (ADS)

Ruby, Michael

In the last decades scanning probe microscopy and spectroscopy have become well-established tools in nanotechnology and surface science. This opened the market for many commercial manufacturers, each with different hardware and software standards. Besides the advantage of a wide variety of available hardware, the diversity may software-wise complicate the data exchange between scientists, and the data analysis for groups working with hardware developed by different manufacturers. Not only the file format differs between manufacturers, but also the data often requires further numerical treatment before publication. SpectraFox is an open-source and independent tool which manages, processes, and evaluates scanning probe spectroscopy and microscopy data. It aims at simplifying the documentation in parallel to measurement, and it provides solid evaluation tools for a large number of data.

Laser-Induced Breakdown Spectroscopy (LIBS) for Monitoring the Formation of Hydroxyapatite Porous Layers

PubMed Central

Sola, Daniel; Paulés, Daniel; Grima, Lorena

2017-01-01

Laser-induced breakdown spectroscopy (LIBS) is applied to characterize the formation of porous hydroxyapatite layers on the surface of 0.8CaSiO3-0.2Ca3(PO4)2 biocompatible eutectic glass immersed in simulated body fluid (SBF). Compositional and structural characterization analyses were also conducted by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy. PMID:29211006

Spatially offset Raman spectroscopy for photon migration investigations in long bone

NASA Astrophysics Data System (ADS)

Sowoidnich, Kay; Churchwell, John H.; Buckley, Kevin; Kerns, Jemma G.; Goodship, Allen E.; Parker, Anthony W.; Matousek, Pavel

2015-07-01

Raman Spectroscopy has become an important technique for assessing the composition of excised sections of bone, and is currently being developed as an in vivo tool for transcutaneous detection of bone disease using spatially offset Raman spectroscopy (SORS). The sampling volume of the Raman technique (and thus the amount of bone material interrogated by SORS) depends on the nature of the photon scattering in the probed tissue. Bone is a complex hierarchical material and to date little is known regarding its diffuse scattering properties which are important for the development and optimization of SORS as a diagnostic tool for characterizing bone disease in vivo. SORS measurements at 830 nm excitation wavelength are carried out on stratified samples to determine the depth from which the Raman signal originates within bone tissue. The measurements are made using a 0.38 mm thin Teflon slice, to give a pronounced and defined spectral signature, inserted in between layers of stacked 0.60 mm thin equine bone slices. Comparing the stack of bone slices with and without underlying bone section below the Teflon slice illustrated that thin sections of bone can lose appreciable number of photons through the unilluminated back surface. The results show that larger SORS offsets lead to progressively larger penetration depth into the sample; different Raman spectral signatures could be retrieved through up to 3.9 mm of overlying bone material with a 7 mm offset. These findings have direct impact on potential diagnostic medical applications; for instance on the detection of bone tumors or areas of infected bone.

Characterization of mammalian cell culture raw materials by combining spectroscopy and chemometrics

PubMed Central

Trunfio, Nicholas; Lee, Haewoo; Starkey, Jason; Agarabi, Cyrus; Liu, Jay

2017-01-01

Two of the primary issues with characterizing the variability of raw materials used in mammalian cell culture, such as wheat hydrolysate, is that the analyses of these materials can be time consuming, and the results of the analyses are not straightforward to interpret. To solve these issues, spectroscopy can be combined with chemometrics to provide a quick, robust and easy to understand methodology for the characterization of raw materials; which will improve cell culture performance by providing an assessment of the impact that a given raw material will have on final product quality. In this study, four spectroscopic technologies: near infrared spectroscopy, middle infrared spectroscopy, Raman spectroscopy, and fluorescence spectroscopy were used in conjunction with principal component analysis to characterize the variability of wheat hydrolysates, and to provide evidence that the classification of good and bad lots of raw material is possible. Then, the same spectroscopic platforms are combined with partial least squares regressions to quantitatively predict two cell culture critical quality attributes (CQA): integrated viable cell density and IgG titer. The results showed that near infrared (NIR) spectroscopy and fluorescence spectroscopy are capable of characterizing the wheat hydrolysate's chemical structure, with NIR performing slightly better; and that they can be used to estimate the raw materials’ impact on the CQAs. These results were justified by demonstrating that of all the components present in the wheat hydrolysates, six amino acids: arginine, glycine, phenylalanine, tyrosine, isoleucine and threonine; and five trace elements: copper, phosphorus, molybdenum, arsenic and aluminum, had a large, statistically significant effect on the CQAs, and that NIR and fluorescence spectroscopy performed the best for characterizing the important amino acids. It was also found that the trace elements of interest were not characterized well by any of the spectral technologies used; however, the trace elements were also shown to have a less significant effect on the CQAs than the amino acids. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers, 33:1127–1138, 2017 PMID:28393480

Remote skin tissue diagnostics in vivo by fiber optic evanescent wave Fourier transform infrared (FEW-FTIR) spectroscopy

NASA Astrophysics Data System (ADS)

Afanasyeva, Natalia I.; Kolyakov, Sergei F.; Butvina, Leonid N.

1998-04-01

The new method of fiber-optical evanescent wave Fourier transform IR (FEW-FTIR) spectroscopy has been applied to the diagnostics of normal tissue, as well as precancerous and cancerous conditions. The FEW-FTIR technique is nondestructive and sensitive to changes of vibrational spectra in the IR region, without heating and damaging human and animal skin tissue. Therefore this method and technique is an ideal diagnostic tool for tumor and cancer characterization at an early stage of development on a molecular level. The application of fiber optic technology in the middle IR region is relatively inexpensive and can be adapted easily to any commercially available tabletop FTIR spectrometers. This method of diagnostics is fast, remote, and can be applied to many fields Noninvasive medical diagnostics of skin cancer and other skin diseases in vivo, ex vivo, and in vitro allow for the development convenient, remote clinical applications in dermatology and related fields. The spectral variations from normal to pathological skin tissue and environmental influence on skin have been measured and assigned in the regions of 850-4000 cm-1. The lipid structure changes are discussed. We are able to develop the spectral histopathology as a fast and informative tool of analysis.

Standoff Time-Resolved Laser-Based Spectroscopy Tools for Sample Characterization and Biosignature Detection

NASA Astrophysics Data System (ADS)

Gasda, P. J.; Acosta-Maeda, T.; Lucey, P. G.; Misra, A. K.; Sharma, S. K.; Taylor, J.

2014-12-01

The NASA Mars2020 rover will be searching for signs of past habitability and past life on Mars. Additionally, the rover mission will prepare a cache of highly significant samples for a future sample return mission. NASA requires these samples to be well characterized; the instruments on the rover must be capable of fine-scale in situ mineralogical or elemental analysis with emphasis on biosignature detection or characterization. We have been developing multiple standoff laser-based instruments at the University of Hawaii, Manoa that are capable of fine-scale in situ chemical analysis and biosignatures detection. By employing a time-resolved spectroscopy, we can perform elemental analysis with Laser-Induced Breakdown Spectroscopy (LIBS), mineral and organic analysis with Raman spectroscopy, and biosignature detection with Laser-Induced Fluorescence (LIF). Each of these techniques share the same optics and detection equipment, allowing us to integrate them into a single, compact instrument. High time-resolution (~100 ns/pulse) is the key to this instrument; with it, the detector only records data when the signal is the brightest. Spectra can be taken during the day, LIBS can be measured without a plasma light background, and the Raman signal can be separated from the mineral fluorescence signal. Since bio-organics have very short fluorescence lifetimes, the new instrument can be used to unambiguously detect bio-organics. The prototype uses a low power (0.5 mJ/pulse) 532 nm laser with a detection limit of < 30 ppm of organics in a sample of Antarctica Dry Valley soil measured from 8 m. Another LIF instrument under development in our lab, called the Biofinder, takes advantage of the extremely intense fluorescence signal produced by organics by using a wide laser spot and a camera to produce LIF images of wide area (25 cm area from 2 m distance with 2 mm/pixel resolution). The Biofinder can quickly assess the area around the rover (at 10 frames/s) by imaging sample cores, drill holes, or outcrops, and then allow the slower but more precise instruments on the rover to characterize the regions of interest. Either of these prototypes would be ideally suited for future NASA missions, including human exploration missions. The next iterations of the instruments will be designed specifically for future astronaut explorers.

Performance of mid infrared spectroscopy in skin cancer cell type identification

NASA Astrophysics Data System (ADS)

Kastl, Lena; Kemper, Björn; Lloyd, Gavin R.; Nallala, Jayakrupakar; Stone, Nick; Naranjo, Valery; Penaranda, Francisco; Schnekenburger, Jürgen

2017-02-01

Marker free optical spectroscopy is a powerful tool for the rapid inspection of pathologically suspicious skin lesions and the non-invasive detection of early skin tumors. This goal can be reached by the combination of signal localization and the spectroscopical detection of chemical cell signatures. We here present the development and application of mid infrared spectroscopy (midIR) for the analysis of skin tumor cell types and three dimensional tissue phantoms towards the application of midIR spectroscopy for fast and reliable skin diagnostics. We developed standardized in vitro skin systems with increasing complexity, from single skin cell types as fibroblasts, keratinocytes and melanoma cells, to mixtures of these and finally three dimensional skin cancer phantoms. The cell systems were characterized with different systems in the midIR range up to 12 μm. The analysis of the spectra by novel data processing algorithms demonstrated the clear separation of all cell types, especially melanoma cells. Special attention and algorithm training was required for closely related mesenchymal cell types as dedifferentiated melanoma cells and fibroblasts. Proof of concept experiments with mixtures of in vivo fluorescence labelled skin cell types allowed the test of the new algorithms performance for the identification of specific cell types. The intense training of the software systems with various samples resulted in a increased sensitivity and specificity of the combined midIR and software system. These data highlight the potential of midIR spectroscopy as sensitive and specific future optical biopsy technology.

Vibrational Spectroscopy of Ionic Liquids.

PubMed

Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

2017-05-24

Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

Explosive detection technology

NASA Astrophysics Data System (ADS)

Doremus, Steven; Crownover, Robin

2017-05-01

The continuing proliferation of improvised explosive devices is an omnipresent threat to civilians and members of military and law enforcement around the world. The ability to accurately and quickly detect explosive materials from a distance would be an extremely valuable tool for mitigating the risk posed by these devices. A variety of techniques exist that are capable of accurately identifying explosive compounds, but an effective standoff technique is still yet to be realized. Most of the methods being investigated to fill this gap in capabilities are laser based. Raman spectroscopy is one such technique that has been demonstrated to be effective at a distance. Spatially Offset Raman Spectroscopy (SORS) is a technique capable of identifying chemical compounds inside of containers, which could be used to detect hidden explosive devices. Coherent Anti-Stokes Raman Spectroscopy (CARS) utilized a coherent pair of lasers to excite a sample, greatly increasing the response of sample while decreasing the strength of the lasers being used, which significantly improves the eye safety issue that typically hinders laser-based detection methods. Time-gating techniques are also being developed to improve the data collection from Raman techniques, which are often hindered fluorescence of the test sample in addition to atmospheric, substrate, and contaminant responses. Ultraviolet based techniques have also shown significant promise by greatly improved signal strength from excitation of resonance in many explosive compounds. Raman spectroscopy, which identifies compounds based on their molecular response, can be coupled with Laser Induced Breakdown Spectroscopy (LIBS) capable of characterizing the sample's atomic composition using a single laser.

Spectroscopy of scattered light for the characterization of micro and nanoscale objects in biology and medicine.

PubMed

Turzhitsky, Vladimir; Qiu, Le; Itzkan, Irving; Novikov, Andrei A; Kotelev, Mikhail S; Getmanskiy, Michael; Vinokurov, Vladimir A; Muradov, Alexander V; Perelman, Lev T

2014-01-01

The biomedical uses for the spectroscopy of scattered light by micro and nanoscale objects can broadly be classified into two areas. The first, often called light scattering spectroscopy (LSS), deals with light scattered by dielectric particles, such as cellular and sub-cellular organelles, and is employed to measure their size or other physical characteristics. Examples include the use of LSS to measure the size distributions of nuclei or mitochondria. The native contrast that is achieved with LSS can serve as a non-invasive diagnostic and scientific tool. The other area for the use of the spectroscopy of scattered light in biology and medicine involves using conducting metal nanoparticles to obtain either contrast or electric field enhancement through the effect of the surface plasmon resonance (SPR). Gold and silver metal nanoparticles are non-toxic, they do not photobleach, are relatively inexpensive, are wavelength-tunable, and can be labeled with antibodies. This makes them very promising candidates for spectrally encoded molecular imaging. Metal nanoparticles can also serve as electric field enhancers of Raman signals. Surface enhanced Raman spectroscopy (SERS) is a powerful method for detecting and identifying molecules down to single molecule concentrations. In this review, we will concentrate on the common physical principles, which allow one to understand these apparently different areas using similar physical and mathematical approaches. We will also describe the major advancements in each of these areas, as well as some of the exciting recent developments.

Through the Looking GLASS: A JWST Exploration of Galaxy Formation and Evolution from Cosmic Dawn to Present Day

NASA Astrophysics Data System (ADS)

Treu, Tommaso; Abramson, L.; Bradac, M.; Brammer, G.; Fontana, A.; Henry, A.; Hoag, A.; Huang, K.; Mason, C.; Morishita, T.; Pentericci, L.; Wang, X.

2017-11-01

We propose a carefully designed set of observations of the lensing cluster Abell 2744 to study intrinsically faint magnified galaxies from the epoch of reionization to redshift of 1, demonstrating and characterizing complementary spectroscopic modes with NIRSPEC and NIRISS. The observations are designed to address the questions: 1) when did reionization happen and what were the sources of reionizing photons? 2) How do baryons cycle in and out of galaxies? This dataset with deep spectroscopy on the cluster and deep multiband NIRCAM imaging in parallel will enable a wealth of investigations and will thus be of interest to a broad section of the astronomical community. The dataset will illustrate the power and challenges of: 1) combining rest frame UV and optical NIRSPEC spectroscopy for galaxies at the epoch of reionization, 2) obtaining spatially resolved emission line maps with NIRISS, 3) combining NIRISS and NIRSPEC spectroscopy. Building on our extensive experience with HST slitless spectroscopy and imaging in clusters of galaxies as part of the GLASS, WISP, SURFSUP, and ASTRODEEP projects, we will provide the following science-enabling products to the community: 1)quantitative comparison of spatially resolved (NIRISS) and spectrally resolved (NIRSPEC) spectroscopy, 2) Object based interactive exploration tools for multi-instrument datasets, 3) Interface for easy forced extractionof slitless spectra based on coordinates, 4) UV-optical spectroscopic templates of highredshift galaxies, 5) NIRCAM parallel catalogs and a list of 26 z>=9 dropouts for spectroscopic follow-up in Cycle-2.

Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

ERIC Educational Resources Information Center

Smith, Rachel; Cantrell, Kevin

2007-01-01

Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

Modulated Raman Spectroscopy for Enhanced Cancer Diagnosis at the Cellular Level

PubMed Central

De Luca, Anna Chiara; Dholakia, Kishan; Mazilu, Michael

2015-01-01

Raman spectroscopy is emerging as a promising and novel biophotonics tool for non-invasive, real-time diagnosis of tissue and cell abnormalities. However, the presence of a strong fluorescence background is a key issue that can detract from the use of Raman spectroscopy in routine clinical care. The review summarizes the state-of-the-art methods to remove the fluorescence background and explores recent achievements to address this issue obtained with modulated Raman spectroscopy. This innovative approach can be used to extract the Raman spectral component from the fluorescence background and improve the quality of the Raman signal. We describe the potential of modulated Raman spectroscopy as a rapid, inexpensive and accurate clinical tool to detect the presence of bladder cancer cells. Finally, in a broader context, we show how this approach can greatly enhance the sensitivity of integrated Raman spectroscopy and microfluidic systems, opening new prospects for portable higher throughput Raman cell sorting. PMID:26110401

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.

Two-photon autofluorescence spectroscopy of oral mucosa tissue

NASA Astrophysics Data System (ADS)

Edward, Kert; Shilagard, Tuya; Qiu, Suimin; Vargas, Gracie

2011-03-01

The survival rate for individuals diagnosed with oral cancer is correlated with the stage of detection. Thus the development of novel techniques for the earliest possible detection of malignancies is of critical importance. Single photon (1P) autofluorescence spectroscopy has proven to be a powerful diagnostic tool in this regard, but 2P (two photon) spectroscopy remains essentially unexplored. In this investigation, a spectroscopic system was incorporated into a custom-built 2P laser scanning microscope. Oral cancer was induced in the buccal pouch of Syrian Golden hamsters by tri-weekly topical application of 9,10-dimethyl-1,2-benzanthracene (DMBA).Three separated sites where investigated in each hamster at four excitation wavelengths from 780 nm to 890 nm. A Total of 8 hamsters were investigated (4 normal and 4 DMBA treated). All investigated sites were imaged via 2p imaging, marked for biopsy, processed for histology and H&E staining, and graded by a pathologist. The in vivo emission spectrum for normal, mild/high grade dysplasia and squamous cell carcinoma is presented. It is shown that the hamsters with various stages of dysplasia are characterized by spectral differences as a function of depth and excitation wavelength, compared to normal hamsters.

Spectroscopic characterization of ligands on the surface of water dispersible NaGdF4:Ln3+ nanocrystals

NASA Astrophysics Data System (ADS)

Cichos, J.; Karbowiak, M.

2012-05-01

For electronic or biomedical applications it is desirable to have ligand-free water-dispersible nanocrystals (NCs). The commonly used FTIR spectroscopy often provides a direct evidence for molecules on the surface. In some cases, however, the strong bands of solvent molecules may obscure the peaks of surface bounded ligands. We show that in this regard the emission spectroscopy may be used as a more reliable probing tool. The relevant information can be obtained from emission and excitation spectra, emission decay times as well as from analysis of relative efficiency of excitation energy transfer from Gd3+ to Eu3+ ions. Using these methods we tested samples obtained by various synthetic routes and indicated that only nitrosonium tetrafluoroborate (NOBF4) removes successfully the organic ligands from the nanocrystals surface, yielding organic ligand-free NCs dispersible in aqueous solutions. The conclusions drawn from emission spectroscopy are useful for interpretation of results of FTIR, Raman and NMR studies. The detailed assignment of FTIR peaks for oleate-capped and oleate-free NCs is also provided. Finally, we point to the risk of drawing erroneous conclusions about colloidal stability of nanocrystals if refractive indexes of NCs and medium are similar.

Phonon shift in chemically exfoliated WS2 nanosheet

NASA Astrophysics Data System (ADS)

Sarkar, Abdus Salam; Pal, Suman Kalyan

2018-04-01

We have synthesized few layer WS2 nanosheets in a low boiling point solvent. Few layer of WS2 sheets are characterized by various techniques such as UV-visible and Raman spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). UV-Vis absorption spectra confirm the well dispersed in isopropyl alcohol. SEM and TEM images indicate the sheet like morphology of WS2. Atomic force microscopy image and room temperature Raman spectroscopy confirm the exfoliation of few layer (4-5 layer) of WS2. Further, Raman spectroscopy was used as a meteorology tool to determine the temperature co-efficient. We have systematically investigated the temperature dependent Raman spectroscopic behavior of few layer WS2. Our results depict the softening of the Raman modes E12g in plane vibration and A1g out of plane vibration with increasing the temperature from 77 K to 300 K. Softening of the Raman modes could be explained in terms of the double resonance which is active in the layered materials. The observed temperature coefficients for two Raman peaks E12g and A1g, are - 0.022 cm-1 and -0.009 cm-1, respectively.

Study of mesoporous CdS-quantum-dot-sensitized TiO2 films by using X-ray photoelectron spectroscopy and AFM

PubMed Central

Wojcieszak, Robert; Raj, Gijo

2014-01-01

Summary CdS quantum dots were grown on mesoporous TiO2 films by successive ionic layer adsorption and reaction processes in order to obtain CdS particles of various sizes. AFM analysis shows that the growth of the CdS particles is a two-step process. The first step is the formation of new crystallites at each deposition cycle. In the next step the pre-deposited crystallites grow to form larger aggregates. Special attention is paid to the estimation of the CdS particle size by X-ray photoelectron spectroscopy (XPS). Among the classical methods of characterization the XPS model is described in detail. In order to make an attempt to validate the XPS model, the results are compared to those obtained from AFM analysis and to the evolution of the band gap energy of the CdS nanoparticles as obtained by UV–vis spectroscopy. The results showed that XPS technique is a powerful tool in the estimation of the CdS particle size. In conjunction with these results, a very good correlation has been found between the number of deposition cycles and the particle size. PMID:24605274

Speciation of adsorbates on surface of solids by infrared spectroscopy and chemometrics.

PubMed

Vilmin, Franck; Bazin, Philippe; Thibault-Starzyk, Frédéric; Travert, Arnaud

2015-09-03

Speciation, i.e. identification and quantification, of surface species on heterogeneous surfaces by infrared spectroscopy is important in many fields but remains a challenging task when facing strongly overlapped spectra of multiple adspecies. Here, we propose a new methodology, combining state of the art instrumental developments for quantitative infrared spectroscopy of adspecies and chemometrics tools, mainly a novel data processing algorithm, called SORB-MCR (SOft modeling by Recursive Based-Multivariate Curve Resolution) and multivariate calibration. After formal transposition of the general linear mixture model to adsorption spectral data, the main issues, i.e. validity of Beer-Lambert law and rank deficiency problems, are theoretically discussed. Then, the methodology is exposed through application to two case studies, each of them characterized by a specific type of rank deficiency: (i) speciation of physisorbed water species over a hydrated silica surface, and (ii) speciation (chemisorption and physisorption) of a silane probe molecule over a dehydrated silica surface. In both cases, we demonstrate the relevance of this approach which leads to a thorough surface speciation based on comprehensive and fully interpretable multivariate quantitative models. Limitations and drawbacks of the methodology are also underlined. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesizing and Characterizing Graphene via Raman Spectroscopy: An Upper-Level Undergraduate Experiment That Exposes Students to Raman Spectroscopy and a 2D Nanomaterial

ERIC Educational Resources Information Center

Parobek, David; Shenoy, Ganesh; Zhou, Feng; Peng, Zhenbo; Ward, Michelle; Liu, Haitao

2016-01-01

In this upper-level undergraduate experiment, students utilize micro-Raman spectroscopy to characterize graphene prepared by mechanical exfoliation and chemical vapor deposition (CVD). The mechanically exfoliated samples are prepared by the students while CVD graphene can be purchased or obtained through outside sources. Owing to the intense Raman…

Radioactive Waste Characterization Strategies; Comparisons Between AK/PK, Dose to Curie Modeling, Gamma Spectroscopy, and Laboratory Analysis Methods- 12194

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

Singledecker, Steven J.; Jones, Scotty W.; Dorries, Alison M.

2012-07-01

In the coming fiscal years of potentially declining budgets, Department of Energy facilities such as the Los Alamos National Laboratory (LANL) will be looking to reduce the cost of radioactive waste characterization, management, and disposal processes. At the core of this cost reduction process will be choosing the most cost effective, efficient, and accurate methods of radioactive waste characterization. Central to every radioactive waste management program is an effective and accurate waste characterization program. Choosing between methods can determine what is classified as low level radioactive waste (LLRW), transuranic waste (TRU), waste that can be disposed of under an Authorizedmore » Release Limit (ARL), industrial waste, and waste that can be disposed of in municipal landfills. The cost benefits of an accurate radioactive waste characterization program cannot be overstated. In addition, inaccurate radioactive waste characterization of radioactive waste can result in the incorrect classification of radioactive waste leading to higher disposal costs, Department of Transportation (DOT) violations, Notice of Violations (NOVs) from Federal and State regulatory agencies, waste rejection from disposal facilities, loss of operational capabilities, and loss of disposal options. Any one of these events could result in the program that mischaracterized the waste losing its ability to perform it primary operational mission. Generators that produce radioactive waste have four characterization strategies at their disposal: - Acceptable Knowledge/Process Knowledge (AK/PK); - Indirect characterization using a software application or other dose to curie methodologies; - Non-Destructive Analysis (NDA) tools such as gamma spectroscopy; - Direct sampling (e.g. grab samples or Surface Contaminated Object smears) and laboratory analytical; Each method has specific advantages and disadvantages. This paper will evaluate each method detailing those advantages and disadvantages including; - Cost benefit analysis (basic materials costs, overall program operations costs, man-hours per sample analyzed, etc.); - Radiation Exposure As Low As Reasonably Achievable (ALARA) program considerations; - Industrial Health and Safety risks; - Overall Analytical Confidence Level. The concepts in this paper apply to any organization with significant radioactive waste characterization and management activities working to within budget constraints and seeking to optimize their waste characterization strategies while reducing analytical costs. (authors)« less

Solvate Structures and Computational/Spectroscopic Characterization of LiPF6 Electrolytes

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

Han, Sang D.; Yun, Sung-Hyun; Borodin, Oleg

2015-04-23

Raman spectroscopy is a powerful method for identifying ion-ion interactions, but only if the vibrational band signature for the anion coordination modes can be accurately deciphered. The present study characterizes the PF6- anion P-F Raman symmetric stretching vibrational band for evaluating the PF6-...Li+ cation interactions within LiPF6 crystalline solvates to create a characterization tool for liquid electrolytes. To facilitate this, the crystal structures for two new solvates—(G3)1:LiPF6 and (DEC)2:LiPF6 with triglyme and diethyl carbonate, respectively—are reported. The information obtained from this analysis provides key guidance about the ionic association information which may be obtained from a Raman spectroscopic evaluation ofmore » electrolytes containing the LiPF6 salt and aprotic solvents. Of particular note is the overlap of the Raman bands for both solvent-separated ion pair (SSIP) and contact ion pair (CIP) coordination in which the PF6- anions are uncoordinated or coordinated to a single Li+ cation, respectively.« less

Quantitative skin color measurements in acanthosis nigricans patients: colorimetry and diffuse reflectance spectroscopy.

PubMed

Pattamadilok, Bensachee; Devpura, Suneetha; Syed, Zain U; Agbai, Oma N; Vemulapalli, Pranita; Henderson, Marsha; Rehse, Steven J; Mahmoud, Bassel H; Lim, Henry W; Naik, Ratna; Hamzavi, Iltefat H

2012-08-01

Tristimulus colorimetry and diffuse reflectance spectroscopy (DRS) are white-light skin reflectance techniques used to measure the intensity of skin pigmentation. The tristimulus colorimeter is an instrument that measures a perceived color and the DRS instrument measures biological chromophores of the skin, including oxy- and deoxyhemoglobin, melanin and scattering. Data gathered from these tools can be used to understand morphological changes induced in skin chromophores due to conditions of the skin or their treatments. The purpose of this study was to evaluate the use of these two instruments in color measurements of acanthosis nigricans (AN) lesions. Eight patients with hyperinsulinemia and clinically diagnosable AN were seen monthly. Skin pigmentation was measured at three sites: the inner forearm, the medial aspect of the posterior neck, and anterior neck unaffected by AN. Of the three, measured tristimulus L*a*b* color parameters, the luminosity parameter L* was found to most reliably distinguish lesion from normally pigmented skin. The DRS instrument was able to characterize a lesion on the basis of the calculated melanin concentration, though melanin is a weak indicator of skin change and not a reliable measure to be used independently. Calculated oxyhemoglobin and deoxyhemoglobin concentrations were not found to be reliable indicators of AN. Tristimulus colorimetry may provide reliable methods for respectively quantifying and characterizing the objective color change in AN, while DRS may be useful in characterizing changes in skin melanin content associated with this skin condition. © 2012 John Wiley & Sons A/S.

Fast characterization of solid organic waste content with near infrared spectroscopy in anaerobic digestion.

PubMed

Charnier, Cyrille; Latrille, Eric; Jimenez, Julie; Lemoine, Margaux; Boulet, Jean-Claude; Miroux, Jérémie; Steyer, Jean-Philippe

2017-01-01

The development of anaerobic digestion involves both co-digestion of solid wastes and optimization of the feeding recipe. Within this context, substrate characterisation is an essential issue. Although it is widely used, the biochemical methane potential is not sufficient to optimize the operation of anaerobic digestion plants. Indeed the biochemical composition in carbohydrates, lipids, proteins and the chemical oxygen demand of the inputs are key parameters for the optimisation of process performances. Here we used near infrared spectroscopy as a robust and less-time consuming tool to predict the solid waste content in carbohydrates, lipids and nitrogen, and the chemical oxygen demand. We built a Partial Least Square regression model with 295 samples and validated it with an independent set of 46 samples across a wide range of solid wastes found in anaerobic digestion units. The standard errors of cross-validation were 90mgO 2 ⋅gTS -1 carbohydrates, 2.5∗10 -2 g⋅gTS -1 lipids, 7.2∗10 -3 g⋅gTS -1 nitrogen and 99mgO 2 ⋅gTS -1 chemical oxygen demand. The standard errors of prediction were 53mgO 2 ⋅gTS -1 carbohydrates, 3.2∗10 -2 g⋅gTS -1 lipids, 8.6∗10 -3 g⋅gTS -1 nitrogen and 83mgO 2 ⋅gTS -1 chemical oxygen demand. These results show that near infrared spectroscopy is a new fast and cost-efficient way to characterize solid wastes content and improve their anaerobic digestion monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterizing Aeroallergens by Infrared Spectroscopy of Fungal Spores and Pollen

PubMed Central

Zimmermann, Boris; Tkalčec, Zdenko; Mešić, Armin; Kohler, Achim

2015-01-01

Background Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens. Methodology The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR). The experimental set includes 71 spore (Basidiomycota) and 121 pollen (Pinales, Fagales and Poales) samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years. Results The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps. PMID:25867755

Is it possible to find presence of lactose in pharmaceuticals? - Preliminary studies by ATR-FTIR spectroscopy and chemometrics

NASA Astrophysics Data System (ADS)

Banas, A.; Banas, K.; Kalaiselvi, S. M. P.; Pawlicki, B.; Kwiatek, W. M.; Breese, M. B. H.

2017-01-01

Lactose and saccharose have the same molecular formula; however, the arrangement of their atoms is different. A major difference between lactose and saccharose with regard to digestion and processing is that it is not uncommon for individuals to be lactose intolerant (around two thirds of the population has a limited ability to digest lactose after infancy), but it is rather unlikely to be saccharose intolerant. The pharmaceutical industry uses lactose and saccharose as inactive ingredients of drugs to help form tablets because of their excellent compressibility properties. Some patients with severe lactose intolerance may experience symptoms of many allergic reactions after taking medicine that contains this substance. People who are specifically "allergic" to lactose (not just lactose intolerant) should not use tablets containing this ingredient. Fourier Transform Infrared (FTIR) spectroscopy has a unique chemical fingerprinting capability and plays a significant important role in the identification and characterization of analyzed samples and hence has been widely used in pharmaceutical science. However, a typical FTIR spectrum collected from tablets contains a myriad of valuable information hidden in a family of tiny peaks. Powerful multivariate spectral data processing can transform FTIR spectroscopy into an ideal tool for high volume, rapid screening and characterization of even minor tablet components. In this paper a method for distinction between FTIR spectra collected for tablets with or without lactose is presented. The results seem to indicate that the success of identifying one component in FTIR spectra collected for pharmaceutical composition (that is tablet) is largely dependent on the choice of the chemometric technique applied.

Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

NASA Astrophysics Data System (ADS)

Battaglieri, M.; Briscoe, B. J.; Celentano, A.; Chung, S.-U.; D'Angelo, A.; De Vita, R.; Döring, M.; Dudek, J.; Eidelman, S.; Fegan, S.; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, D. I.; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, D. G.; Ketzer, B.; Klein, F. J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, V.; McKinnon, B.; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, A.; Salgado, C.; Santopinto, E.; Sarantsev, A. V.; Sato, T.; Schlüter, T.; [Silva]da Silva, M. L. L.; Stankovic, I.; Strakovsky, I.; Szczepaniak, A.; Vassallo, A.; Walford, N. K.; Watts, D. P.; Zana, L.

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids.

PubMed

Gumí-Audenis, Berta; Costa, Luca; Carlá, Francesco; Comin, Fabio; Sanz, Fausto; Giannotti, Marina I

2016-12-19

Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information.

Study of carotenoids in cyanobacteria by Raman spectroscopy.

PubMed

de Oliveira, Vanessa End; Neves Miranda, Marcela A C; Soares, Maria Carolina Silva; Edwards, Howell G M; de Oliveira, Luiz Fernando Cappa

2015-01-01

Cyanobacteria have established dominant aquatic populations around the world, generally in aggressive environments and under severe stress conditions, e.g., intense solar radiation. Several marine strains make use of compounds such as the polyenic molecules for their damage protection justifying the range of colours observed for these species. The peridinin/chlorophyll-a/protein complex is an excellent example of essential structures used for self-prevention; their systems allow to them surviving under aggressive environments. In our simulations, few protective dyes are required to the initial specimen defense; this is an important data concern the synthetic priority in order to supply adequate damage protection. Raman measurements obtained with 1064 and 514.5 nm excitations for Cylindrospermopsis raciborskii and Microcystis aeruginosa strains shows bands assignable to the carotenoid peridinin. It was characterized by bands at 1940, 1650, 1515, 1449, 1185, 1155 and 1000 cm(-1) assigned to ν(C=C=C) (allenic vibration), ν(C=C/CO), ν(C=C), δ(C-H, C-18/19), δ(C-H), ν(C-C), and ρ(C-CH3), respectively. Recognition by Raman spectroscopy proved to be an important tool for preliminaries detections and characterization of polyene molecules in several algae, besides initiate an interesting discussion about their synthetic priority. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis, characterization, redox behavior, DNA and protein binding and antibacterial activity studies of ruthenium(II) complexes of bidentate schiff bases.

PubMed

Paul, Hena; Sen, Buddhadeb; Mondal, Tapan Kumar; Chattopadhyay, Pabitra

2017-08-03

Two new ruthenium(II) complexes of Schiff base ligands (L) derived from cinnamaldehyde and ethylenediamine formulated as [Ru(L)(bpy) 2 ](ClO 4 ) 2 , where L 1 = N,N'-bis(4-nitrocinnamald-ehyde)ethylenediamine and L 2 = N,N'-bis(2-nitrocinnamaldehyde)-ethylenediamine for complex 1 and 2, respectively, were isolated in pure form. The complexes were characterized by physicochemical and spectroscopic methods. The electrochemical behavior of the complexes showed the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms. The interaction of the complexes with calf thymus DNA (CT-DNA) using absorption, emission spectral studies and electrochemical techniques have been used to determine the binding constant, K b and the linear Stern-Volmer quenching constant, K SV . The results indicate that the ruthenium(II) complexes interact with CT-DNA strongly in a groove binding mode. The interactions of bovine serum albumin (BSA) with the complexes were also investigated with the help of absorption and fluorescence spectroscopy tools. Absorption spectroscopy proved the formation of a ground state BSA-[Ru(L)(bpy) 2 ](ClO 4 ) 2 complex. The antibacterial study showed that the Ru(II) complexes (1 and 2) have better activity than the standard antibiotics but weak activity than the ligands.

Analysis of Complex Carbohydrate Composition in Plant Cell Wall Using Fourier Transformed Mid-Infrared Spectroscopy (FT-IR).

PubMed

Badhan, Ajay; Wang, Yuxi; McAllister, Tim A

2017-01-01

Fourier transformed mid-infrared spectroscopy (FTIR) is a powerful tool for compositional analysis of plant cell walls (Acebes et al., Front Plant Sci 5:303, 2014; Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Badhan et al., BioMed Res Int 2015: 562952, 2015; Roach et al., Plant Physiol 156:1351-1363, 2011). The infrared spectrum generates a fingerprint of a sample with absorption peaks corresponding to the frequency of vibrations between the bonds of the atoms making up the material. Here, we describe a method focused on the use of FTIR in combination with principal component analysis (PCA) to characterize the composition of the plant cell wall. This method has been successfully used to study complex enzyme saccharification processes like rumen digestion to identify recalcitrant moieties in low-quality forage which resist rumen digestion (Badhan et al., BioMed Res Int 2015: 562952, 2015), as well as to characterize cell wall mutant lines or transgenic lines expressing exogenous hydrolases (Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Roach et al., Plant Physiol 156:1351-1363, 2011). The FTIR method described here facilitates high-throughput identification of the major compositional differences across a large set of samples in a low cost and nondestructive manner.

Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids

PubMed Central

Gumí-Audenis, Berta; Costa, Luca; Carlá, Francesco; Comin, Fabio; Sanz, Fausto; Giannotti, Marina I.

2016-01-01

Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information. PMID:27999368

Molecular Chemistry and Engineering of Boron-Modified Polyorganosilazanes as New Processable and Functional SiBCN Precursors.

PubMed

Viard, Antoine; Fonblanc, Diane; Schmidt, Marion; Lale, Abhijeet; Salameh, Chrystelle; Soleilhavoup, Anne; Wynn, Mélanie; Champagne, Philippe; Cerneaux, Sophie; Babonneau, Florence; Chollon, Georges; Rossignol, Fabrice; Gervais, Christel; Bernard, Samuel

2017-07-06

A series of boron-modified polyorganosilazanes was synthesized from a poly(vinylmethyl-co-methyl)silazane and controlled amounts of borane dimethyl sulfide. The role of the chemistry behind their synthesis has been studied in detail by using solid-state NMR spectroscopy, FTIR spectroscopy, and elemental analysis. The intimate relationship between the chemistry and the processability of these polymers is discussed. Polymers with low boron contents displayed appropriate requirements for facile processing in solution, such as impregnation of host carbon materials, which resulted in the design of mesoporous monoliths with a high specific surface area after pyrolysis. Polymers with high boron content are more appropriate for solid-state processing to design mechanically robust monolith-type macroporous and dense structures after pyrolysis. Boron acts as a crosslinking element, which offers the possibility to extend the processability of polyorganosilazanes and suppress the distillation of oligomeric fragments in the low-temperature region of their thermal decomposition (i.e., pyrolysis) at 1000 °C under nitrogen. Polymers with controlled and high ceramic yields were generated. We provide a comprehensive mechanistic study of the two-step thermal decomposition based on a combination of thermogravimetric experiments coupled with elemental analysis, solid-state NMR spectroscopy, and FTIR spectroscopy. Selected characterization tools allowed the investigation of specific properties of the monolith-type SiBCN materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Raman spectroscopy and immunohistochemistry for schwannoma characterization: a case study

NASA Astrophysics Data System (ADS)

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

2016-03-01

The schwannomas is a tumour of the tissue that covers nerves, called the nerve sheath. Schwannomas are often benign tumors of the Schwan cells, which are the principal glia of the peripheral nervous system (PNS). Preoperative diagnosis of this lesion usually is difficult, therefore, new techniques are being studied as pre surgical evaluation. Among these, Raman spectroscopy, that enables the biochemical identification of the tissue analyzed by their optical properties, may be used as a tool for schwannomas diagnosis. The aim of this study was to discriminate between normal nervous tissue and schwannoma through the confocal Raman spectroscopy and Raman optical fiber-based techniques combined with immunohistochemical analysis. Twenty spectra were analyzed from a normal nerve tissue sample (10) and schwannoma (10) by Holospec f / 1.8 (Kayser Optical Systems) coupled to an optical fiber with a 785nm laser line source. The data were pre-processed and vector normalized. The average analysis and standard deviation was performed associated with cluster analysis. AML, 1A4, CD34, Desmin and S-100 protein markers were used for immunohistochemical analysis. Immunohistochemical analysis was positive only for protein S-100 marker which confirmed the neural schwanomma originality. The immunohistochemistry analysis were important to determine the source of the injury, whereas Raman spectroscopy were able to differentiated tissues types indicating important biochemical changes between normal and benign neoplasia.

Micro-Raman spectroscopy shows how the coating process affects the characteristics of hydroxylapatite.

PubMed

Saber-Samandari, Saeed; Alamara, Kadhim; Saber-Samandari, Samaneh; Gross, Karlis A

2013-12-01

The diversity in the structural and chemical state of apatites allows implant manufacturers to fine-tune implant properties. This requires suitable manufacturing processes and characterization tools to adjust the amorphous phase and hydroxyl content from the source hydroxylapatite. Hydroxylapatite was processed by high-velocity oxy-fuel spraying, plasma spraying and flame spraying, and primarily analyzed by Raman spectroscopy. Investigation of rounded splats, the building blocks of thermal spray coatings, allowed correlation between the visual identity of the splat surface and the Raman spectra. Splats were heat-treated to crystallize any remaining amorphous phase. The ν1 PO4 stretching peak at 950-970 cm(-1) displayed the crystalline order, but the hydroxyl peak at 3572 cm(-1) followed the degree of dehydroxylation. Hydroxyl loss was greatest for flame-sprayed particles, which create the longest residence time for the melted particle. Higher-frequency hydroxyl peaks in flame- and plasma-sprayed splats indicated a lower structural order for the recrystallized hydroxylapatite within the splats. Crystallization at 700 °C has shown potential for revealing hydroxyl ions previously trapped in amorphous calcium phosphate. This work compares Fourier transform infrared and Raman spectroscopy to measure the hydroxyl content in rapidly solidified apatites and shows that Raman spectroscopy is more suitable. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Surface Characterization.

ERIC Educational Resources Information Center

Fulghum, J. E.; And Others

1989-01-01

This review is divided into the following analytical methods: ion spectroscopy, electron spectroscopy, scanning tunneling microscopy, atomic force microscopy, optical spectroscopy, desorption techniques, and X-ray techniques. (MVL)

Characterization of the Ground Paprika Samples Using Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Gucsik, A.; Veres, M.; Himics, L.; Rigó, I.

2017-11-01

Micro-Raman spectroscopy as a powerful technique can be used in food industry, especially in the ground pepper or paprika characterization in order to deter-mine the paprika sample’s origin as well as their quality.

A 90-Day Oral Toxicity Study and a 5-Day Metabolism Study of Diisopropyl Methylphosphonate (DIMP) in Mink.

DTIC Science & Technology

1992-06-01

characterized with infrared and ultraviolet/visible spectroscopy , nuclear magnetic resonance analysis and gas and thin-layer chromatography. These...comparison gas chromatographic major peak profile of diisopropyl methylphosphonate. In brief, infrared and ultraviolet/visible spectroscopy and nuclear...An aliquot of this batch was analyzed by MRI, Kansas City, MO. The characterization consisted of determination of physical properties, spectroscopy

Raman spectroscopy as a tool to characterize heterogenite (CoO·OH) (Katanga Province, Democratic Republic of Congo)

NASA Astrophysics Data System (ADS)

Burlet, C.; Vanbrabant, Y.; Goethals, H.; Thys, T.; Dupin, L.

2011-10-01

Natural heterogenite (CoO·OH) samples were studied by Raman microspectroscopy, electronic microprobe and Electronic BackScattered Diffraction (EBSD). Raw samples and polished sections were made from 10 mines covering the Katanga copperbelt (Katanga Province, Democratic Republic of Congo). Four typical Raman responses have been obtained leading to investigate the laser-induced dehydroxylation of heterogenite into a Co-spinel structure. The results are also compared with EBSD patterns from oven heated heterogenite samples. A close relationship was established between the chemical substitutions of Co by mainly Cu, Ni, Mn and Al and their impact on the mineral Raman response.

Biotransformation of tissue-specific hormone tibolone with fungal culture Trichothecium roseum

NASA Astrophysics Data System (ADS)

Shah, Syed Adnan Ali; Sultan, Sadia; Zaimi bin Mohd Noor, M.

2013-06-01

Whole cells based biotransformation is an important tool for bioconversion of steroids. It can be used to synthesize biologically potent compounds with diverse structures. Biotransformation of tissue-specific hormone tibolone (1) with Trichothecium roseum (ATCC 13411) has being carried out for the first time. Two new and three known metabolites 2-6 were isolated from fermentation of tibolone (1) with Trichothecium roseum and their structures were characterized by 2D NMR spectroscopy and mass spectrometry. The relative stereochemistry of new metabolites 5 and 6 was deduced by 2D NOESY experiments. The effect of cultures on tibolone structural modifications and time-course studies has also been conducted.

Raman spectroscopic investigation of thorium dioxide-uranium dioxide (ThO₂-UO₂) fuel materials.

PubMed

Rao, Rekha; Bhagat, R K; Salke, Nilesh P; Kumar, Arun

2014-01-01

Raman spectroscopic investigations were carried out on proposed nuclear fuel thorium dioxide-uranium dioxide (ThO2-UO2) solid solutions and simulated fuels based on ThO2-UO2. Raman spectra of ThO2-UO2 solid solutions exhibited two-mode behavior in the entire composition range. Variations in mode frequencies and relative intensities of Raman modes enabled estimation of composition, defects, and oxygen stoichiometry in these compounds that are essential for their application. The present study shows that Raman spectroscopy is a simple, promising analytical tool for nondestructive characterization of this important class of nuclear fuel materials.

Characterization and classification of oral tissues using excitation and emission matrix: a statistical modeling approach

NASA Astrophysics Data System (ADS)

Kanniyappan, Udayakumar; Gnanatheepaminstein, Einstein; Prakasarao, Aruna; Dornadula, Koteeswaran; Singaravelu, Ganesan

2017-02-01

Cancer is one of the most common human threats around the world and diagnosis based on optical spectroscopy especially fluorescence technique has been established as the standard approach among scientist to explore the biochemical and morphological changes in tissues. In this regard, the present work aims to extract spectral signatures of the various fluorophores present in oral tissues using parallel factor analysis (PARAFAC). Subsequently, the statistical analysis also to be performed to show its diagnostic potential in distinguishing malignant, premalignant from normal oral tissues. Hence, the present study may lead to the possible and/or alternative tool for oral cancer diagnosis.

Scanning Angle Raman spectroscopy in polymer thin film characterization

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

Nguyen, Vy H.T.

The focus of this thesis is the application of Raman spectroscopy for the characterization of thin polymer films. Chapter 1 provides background information and motivation, including the fundamentals of Raman spectroscopy for chemical analysis, scanning angle Raman scattering and scanning angle Raman scattering for applications in thin polymer film characterization. Chapter 2 represents a published manuscript that focuses on the application of scanning angle Raman spectroscopy for the analysis of submicron thin films with a description of methodology for measuring the film thickness and location of an interface between two polymer layers. Chapter 3 provides an outlook and future directionsmore » for the work outlined in this thesis. Appendix A, contains a published manuscript that outlines the use of Raman spectroscopy to aid in the synthesis of heterogeneous catalytic systems. Appendix B and C contain published manuscripts that set a foundation for the work presented in Chapter 2.« less

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

Bailey, J.E.; Adams, R.; Carlson, A.L.

Stark-shift measurements using emission spectroscopy are a powerful tool for advancing understanding in many plasma physics experiments. The authors use simultaneous 2-D-spatial and time-resolved spectra to study the electric field evolution in the 20 TW Particle Beam Fusion Accelerator II ion diode acceleration gap. Fiber optic arrays transport light from the gap to remote streaked spectrographs operated in a multiplexed mode that enables recording time-resolved spectra from eight spatial locations on a single instrument. Design optimization and characterization measurements of the multiplexed spectrograph properties include the astigmatism, resolution, dispersion variation, and sensitivity. A semi-automated line-fitting procedure determines the Stark shiftmore » and the related uncertainties. Fields up to 10 MV/cm are measured with an accuracy {+-}2--4%. Detailed tests of the fitting procedure confirm that the wavelength shift uncertainties are accurate to better than {+-}20%. Development of an active spectroscopy probe technique that uses laser-induced fluorescence from an injected atomic beam to obtain 3-D space- and time-resolved measurements of the electric and magnetic fields is in progress.« less

Efficient dermal delivery of retinyl palmitate: Progressive polarimetry and Raman spectroscopy to evaluate the structure and efficacy.

PubMed

Lee, Jun Bae; Lee, Dong Ryeol; Choi, Nak Cho; Jang, Jihui; Park, Chun Ho; Yoon, Moung Seok; Lee, Miyoung; Won, Kyoungae; Hwang, Jae Sung; Kim, B Moon

2015-10-12

Over the past decades, there has been a growing interest in dermal drug delivery. Although various novel delivery devices and methods have been developed, dermal delivery is still challenging because of problems such as poor drug permeation, instability of vesicles and drug leakage from vesicles induced by fusion of vesicles. To solve the vesicle instability problems in current dermal delivery systems, we developed materials comprised of liquid crystals as a new delivery vehicle of retinyl palmitate and report the characterization of the liquid crystals using a Mueller matrix polarimetry. The stability of the liquid-crystal materials was evaluated using the polarimeter as a novel evaluation tool along with other conventional methods. The dermal delivery of retinyl palmitate was investigated through the use of confocal Raman spectroscopy. The results indicate that the permeation of retinyl palmitate was enhanced by up to 106% compared to that using an ordinary emulsion with retinyl palmitate. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of wavelet packet transform to compressing Raman spectra data

NASA Astrophysics Data System (ADS)

Chen, Chen; Peng, Fei; Cheng, Qinghua; Xu, Dahai

2008-12-01

Abstract The Wavelet transform has been established with the Fourier transform as a data-processing method in analytical fields. The main fields of application are related to de-noising, compression, variable reduction, and signal suppression. Raman spectroscopy (RS) is characterized by the frequency excursion that can show the information of molecule. Every substance has its own feature Raman spectroscopy, which can analyze the structure, components, concentrations and some other properties of samples easily. RS is a powerful analytical tool for detection and identification. There are many databases of RS. But the data of Raman spectrum needs large space to storing and long time to searching. In this paper, Wavelet packet is chosen to compress Raman spectra data of some benzene series. The obtained results show that the energy retained is as high as 99.9% after compression, while the percentage for number of zeros is 87.50%. It was concluded that the Wavelet packet has significance in compressing the RS data.

Ambient-Pressure X-ray Photoelectron Spectroscopy to Characterize the Solid/Liquid Interface: Probing the Electrochemical Double Layer

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

Favaro, Marco; Liu, Zhi; Crumlin, Ethan J.

Ambient-pressure X-ray photoelectron spectroscopy (APXPS) has contributed greatly to a wide range of research fields, including environmental science, catalysis, and electrochemistry, to name a few. The use of this technique at synchrotron facilities primarily focused on probing the solid/gas interface; however, it quickly advanced to the probing of liquid/vapor interfaces and solid/liquid interfaces through an X-ray-transparent window. Most recently, combining APXPS with “Tender” X-rays (~2.5 keV to 8 keV) on beamline 9.3.1 at the Advanced Light Source in Lawrence Berkeley National Laboratory (which can generate photoelectrons with much longer inelastic mean free paths) has enabled us to probe the solid/liquidmore » interface without needing a window. This innovation allows us to probe interfacial chemistries of electrochemically controlled solid/liquid interfaces undergoing charge transfer reactions. Lastly, these advancements have transitioned APXPS from a traditional surface science tool to an essential interface science technique.« less

Detection of atomic scale changes in the free volume void size of three-dimensional colorectal cancer cell culture using positron annihilation lifetime spectroscopy.

PubMed

Axpe, Eneko; Lopez-Euba, Tamara; Castellanos-Rubio, Ainara; Merida, David; Garcia, Jose Angel; Plaza-Izurieta, Leticia; Fernandez-Jimenez, Nora; Plazaola, Fernando; Bilbao, Jose Ramon

2014-01-01

Positron annihilation lifetime spectroscopy (PALS) provides a direct measurement of the free volume void sizes in polymers and biological systems. This free volume is critical in explaining and understanding physical and mechanical properties of polymers. Moreover, PALS has been recently proposed as a potential tool in detecting cancer at early stages, probing the differences in the subnanometer scale free volume voids between cancerous/healthy skin samples of the same patient. Despite several investigations on free volume in complex cancerous tissues, no positron annihilation studies of living cancer cell cultures have been reported. We demonstrate that PALS can be applied to the study in human living 3D cell cultures. The technique is also capable to detect atomic scale changes in the size of the free volume voids due to the biological responses to TGF-β. PALS may be developed to characterize the effect of different culture conditions in the free volume voids of cells grown in vitro.

Discovery of Cellulose Surface Layer Conformation by Nonlinear Vibrational Spectroscopy

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

Zhang, Libing; Fu, Li; Wang, Hong-fei

2017-03-14

Significant questions remain with respect to the structure and polymorphs of cellulose. These include the cellulose surface layers and the bulk crystalline core as well as the conformational differences. The Total Internal Reflection Sum Frequency Generation Vibrational Spectroscopy (TIR-SFG-VS) combined with the conventional SFG-VS (non-TIR) can help to resolve these questions by selectively characterizing the molecular structures of surface layers and the crystalline core of cellulose. From the SFG spectra in the C-H and O-H regions, we found that the surface layers of Avicel are essentially amorphous; while the surface layers of Iβ cellulose are crystalline but with different structuralmore » and spectroscopic signatures than that of its crystalline core. This work demonstrates the capacity of TIR and Non-TIR SFG-VS tools in selectively studying the structures and polymorphs of cellulose. In addition, these results also suggest that the assignments of major vibrational peaks for cellulose need to be further determined.« less

Supercritical angle fluorescence as a tool to study the interaction between lipid bilayer and peptides

NASA Astrophysics Data System (ADS)

Dubois, Valentin; Serrano, Diana; Seeger, Stefan

2017-06-01

The understanding of processes occurring at the interface between two media are of prior importance in various fields of research, from material sciences to biology. A custom-made microscope objective based on the supercritical angle technique was developed in our group, allowing to probe these interfacial events by carrying out surface-sensitive and low invasive spectroscopy of aqueous samples. A biological example of particular interest is the comprehension of neurodegenerative diseases which seem caused by the interaction of specific peptides with the membrane of the neurons. Taking advantage of our optical setup, we used supercritical angle fluorescence spectroscopy to specifically monitor the interaction between a supported lipid bilayer (SLB) and the Amyloid β peptide, notably responsible of the Alzheimer disease. Different forms of the peptide (40 and 42 amino acids composition) were tested and the interfacial fluorescence measured to get information about the lipid integrity and mobility. The adsorption of the peptide was also characterized in terms of kinetic and affinity.

Detection of Atomic Scale Changes in the Free Volume Void Size of Three-Dimensional Colorectal Cancer Cell Culture Using Positron Annihilation Lifetime Spectroscopy

PubMed Central

Castellanos-Rubio, Ainara; Merida, David; Garcia, Jose Angel; Plaza-Izurieta, Leticia; Fernandez-Jimenez, Nora; Plazaola, Fernando; Bilbao, Jose Ramon

2014-01-01

Positron annihilation lifetime spectroscopy (PALS) provides a direct measurement of the free volume void sizes in polymers and biological systems. This free volume is critical in explaining and understanding physical and mechanical properties of polymers. Moreover, PALS has been recently proposed as a potential tool in detecting cancer at early stages, probing the differences in the subnanometer scale free volume voids between cancerous/healthy skin samples of the same patient. Despite several investigations on free volume in complex cancerous tissues, no positron annihilation studies of living cancer cell cultures have been reported. We demonstrate that PALS can be applied to the study in human living 3D cell cultures. The technique is also capable to detect atomic scale changes in the size of the free volume voids due to the biological responses to TGF-β. PALS may be developed to characterize the effect of different culture conditions in the free volume voids of cells grown in vitro. PMID:24392097

Fluorescence fluctuation spectroscopy for clinical applications

NASA Astrophysics Data System (ADS)

Olson, Eben

Fluorescence correlation spectroscopy (FCS) and the related techniques of brightness analysis have become standard tools in biological and biophysical research. By analyzing the statistics of fluorescence emitted from a restricted volume, a number of parameters including concentrations, diffusion coefficients and chemical reaction rates can be determined. The single-molecule sensitivity, spectral selectivity, small sample volume and non-perturbative measurement mechanism of FCS make it an excellent technique for the study of molecular interactions. However, its adoption outside of the research laboratory has been limited. Potential reasons for this include the cost and complexity of the required apparatus. In this work, the application of fluorescence fluctuation analysis to several clinical problems is considered. Optical designs for FCS instruments which reduce the cost and increase alignment tolerance are presented. Brightness analysis of heterogenous systems, with application to the characterization of protein aggregates and multimer distributions, is considered. Methods for FCS-based assays of two clinically relevant proteins, von Willebrand factor and haptoglobin, are presented as well.

Application of Surface Analysis Methods to Nanomaterials: Summaryof ISO/TC 201 Technical Report: ISO 14187:2011 -Surface Chemical Analysis- Characterization of Nanomaterials

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

Baer, Donald R.

ISO Technical Report (TR) 14187 provides an introduction to (and examples of) the information that can be obtained about nanostructured materials using surface-analysis tools. In addition, both general issues and challenges associated with characterising nanostructured materials and the specific opportunities and challenges associated with individual analytical methods are identified. As the size of objects or components of materials approaches a few nanometres, the distinctions among 'bulk', 'surface' and 'particle' analysis blur. This Technical Report focuses on issues specifically relevant to surface chemical analysis of nanostructured materials. The report considers a variety of analysis methods but focuses on techniques that aremore » in the domain of ISO/TC 201 including Auger electron spectroscopy, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and scanning probe microscopy. Measurements of nanoparticle surface properties such as surface potential that are often made in a solution are not discussed.« less

Fluorescence Lifetime Imaging and Spectroscopy as Tools for Nondestructive Analysis of Works of Art

NASA Astrophysics Data System (ADS)

Comelli, Daniela; D'Andrea, Cosimo; Valentini, Gianluca; Cubeddu, Rinaldo; Colombo, Chiara; Toniolo, Lucia

2004-04-01

A system for advanced fluorescence investigation of works of art has been assembled and integrated in a characterization procedure that allows one to localize and identify organic compounds that are present in artworks. At the beginning of the investigation, fluorescence lifetime imaging and spectroscopy address a selective microsampling of the artwork. Then analytical measurements of microsamples identify the chemical composition of the materials under investigation. Finally, on the basis of fluorescence lifetime and amplitude maps, analytical data are extended to the whole artwork. In such a way, information on the spatial distribution of organic materials can be inferred. These concepts have been successfully applied in an extensive campaign for analysis of Renaissance fresco paintings in Castiglione Olona, Italy. Residue of various types of glue and stucco left from a restoration carried out in the early 1970s was localized and classified. Insight into the technique used by the painter to make gilded reliefs was also obtained.

Ambient-Pressure X-ray Photoelectron Spectroscopy to Characterize the Solid/Liquid Interface: Probing the Electrochemical Double Layer

DOE PAGES

Favaro, Marco; Liu, Zhi; Crumlin, Ethan J.

2017-03-31

Ambient-pressure X-ray photoelectron spectroscopy (APXPS) has contributed greatly to a wide range of research fields, including environmental science, catalysis, and electrochemistry, to name a few. The use of this technique at synchrotron facilities primarily focused on probing the solid/gas interface; however, it quickly advanced to the probing of liquid/vapor interfaces and solid/liquid interfaces through an X-ray-transparent window. Most recently, combining APXPS with “Tender” X-rays (~2.5 keV to 8 keV) on beamline 9.3.1 at the Advanced Light Source in Lawrence Berkeley National Laboratory (which can generate photoelectrons with much longer inelastic mean free paths) has enabled us to probe the solid/liquidmore » interface without needing a window. This innovation allows us to probe interfacial chemistries of electrochemically controlled solid/liquid interfaces undergoing charge transfer reactions. Lastly, these advancements have transitioned APXPS from a traditional surface science tool to an essential interface science technique.« less

Simulating pump-probe photoelectron and absorption spectroscopy on the attosecond timescale with time-dependent density functional theory.

PubMed

De Giovannini, Umberto; Brunetto, Gustavo; Castro, Alberto; Walkenhorst, Jessica; Rubio, Angel

2013-05-10

Molecular absorption and photoelectron spectra can be efficiently predicted with real-time time-dependent density functional theory. We show herein how these techniques can be easily extended to study time-resolved pump-probe experiments, in which a system response (absorption or electron emission) to a probe pulse is measured in an excited state. This simulation tool helps with the interpretation of fast-evolving attosecond time-resolved spectroscopic experiments, in which electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump-pulse duration, intensity, frequency, and time delay), which are absent in a conventional steady-state experiment, provide additional information about electronic structure and dynamics that improve characterization of a system. As an extension of this approach, time-dependent 2D spectroscopy can also be simulated, in principle, for large-scale structures and extended systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature-dependent vibrational spectroscopy to study order-disorder transitions in charge transfer complexes

NASA Astrophysics Data System (ADS)

Isaac, Rohan; Goetz, Katelyn P.; Roberts, Drew; Jurchescu, Oana D.; McNeil, L. E.

2018-02-01

Charge-transfer (CT) complexes are a promising class of materials for the semiconductor industry because of their versatile properties. This class of compounds shows a variety of phase transitions, which are of interest because of their potential impact on the electronic characteristics. Here temperature-dependent vibrational spectroscopy is used to study structural phase transitions in a set of organic CT complexes. Splitting and broadening of infrared-active phonons in the complex formed between pyrene and pyromellitic dianhydride (PMDA) confirm the structural transition is of the order-disorder type and complement previous x-ray diffraction (XRD) results. We show that this technique is a powerful tool to characterize transitions, and apply it to a range of binary CT complexes composed of polyaromatic hyrdocarbons (anthracene, perylene, phenanthrene, pyrene, and stilbene) and PMDA. We extend the understanding of transitions in perylene-PMDA and pyrene-PMDA, and show that there are no order-disorder transitions present in anthracene-PMDA, stilbene-PMDA and phenanthrene-PMDA in the temperature range investigated here.

Raman shifts in electron-irradiated monolayer MoS 2

DOE PAGES

Parkin, William M.; Balan, Adrian; Liang, Liangbo; ...

2016-03-21

Here, we report how the presence of electron-beam-induced sulfur vacancies affects first-order Raman modes and correlate the effects with the evolution of the in situ transmission-electron microscopy (TEM) two-terminal conductivity of monolayer MoS 2 under electron irradiation. We observe a redshift in the E Raman peak and a less pronounced blueshift in the A' 1 peak with increasing electron dose. Using energy-dispersive X-ray spectroscopy (EDS), we show that irradiation causes partial removal of sulfur and correlate the dependence of the Raman peak shifts with S vacancy density (a few %), which is confirmed by first-principles density functional theory calculations. Inmore » situ device current measurements show exponential decrease in channel current upon irradiation. Our analysis demonstrates that the observed frequency shifts are intrinsic properties of the defective systems and that Raman spectroscopy can be used as a quantitative diagnostic tool to characterize MoS 2-based transport channels.« less

Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

PubMed

Nguyen, Luan; Tao, Franklin Feng

2018-02-01

Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

Application of the Pulsed Photoacoustic Spectroscopy in Biomedicine

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

Gutierrez-Juarez, G.; Sims, M. J.; Gupta, S. K.

2008-08-11

The use of optical spectroscopy as a diagnostic tool in biomedical applications and research has grown considerably in the last two decades. One of them is the pulsed photoacoustic or optoacoustic, which promises to be one of the most important tools for disease diagnostic studies, because while most spectroscopies exploit the optical nature of the light-tissue interaction, this field of photoacoustics uses optical energy to generate an acoustic wave which propagates in the tissue environment. The acoustic wave propagation is fundamentally related to various tissue properties and an analysis of the wave dynamics can provide insights into these properties. Thismore » work presents a review on pulsed photoacoustic spectroscopy of several photoacoustic methods to derive information about tissue and tissue phantoms.« less

Model-Based Infrared Metrology for Advanced Technology Nodes and 300 mm Wafer Processing

NASA Astrophysics Data System (ADS)

Rosenthal, Peter A.; Duran, Carlos; Tower, Josh; Mazurenko, Alex; Mantz, Ulrich; Weidner, Peter; Kasic, Alexander

2005-09-01

The use of infrared spectroscopy for production semiconductor process monitoring has evolved recently from primarily unpatterned, i.e. blanket test wafer measurements in a limited historical application space of blanket epitaxial, BPSG, and FSG layers to new applications involving patterned product wafer measurements, and new measurement capabilities. Over the last several years, the semiconductor industry has adopted a new set of materials associated with copper/low-k interconnects, and new structures incorporating exotic materials including silicon germanium, SOI substrates and high aspect ratio trenches. The new device architectures and more chemically sophisticated materials have raised new process control and metrology challenges that are not addressed by current measurement technology. To address the challenges we have developed a new infrared metrology tool designed for emerging semiconductor production processes, in a package compatible with modern production and R&D environments. The tool incorporates recent advances in reflectance instrumentation including highly accurate signal processing, optimized reflectometry optics, and model-based calibration and analysis algorithms. To meet the production requirements of the modern automated fab, the measurement hardware has been integrated with a fully automated 300 mm platform incorporating front opening unified pod (FOUP) interfaces, automated pattern recognition and high throughput ultra clean robotics. The tool employs a suite of automated dispersion-model analysis algorithms capable of extracting a variety of layer properties from measured spectra. The new tool provides excellent measurement precision, tool matching, and a platform for deploying many new production and development applications. In this paper we will explore the use of model based infrared analysis as a tool for characterizing novel bottle capacitor structures employed in high density dynamic random access memory (DRAM) chips. We will explore the capability of the tool for characterizing multiple geometric parameters associated with the manufacturing process that are important to the yield and performance of advanced bottle DRAM devices.

Fragment-Based Drug Discovery Using NMR Spectroscopy

PubMed Central

Harner, Mary J.; Frank, Andreas O.; Fesik, Stephen W.

2013-01-01

Nuclear magnetic resonance (NMR) spectroscopy has evolved into a powerful tool for fragment-based drug discovery over the last two decades. While NMR has been traditionally used to elucidate the three-dimensional structures and dynamics of biomacromolecules and their interactions, it can also be a very valuable tool for the reliable identification of small molecules that bind to proteins and for hit-to-lead optimization. Here, we describe the use of NMR spectroscopy as a method for fragment-based drug discovery and how to most effectively utilize this approach for discovering novel therapeutics based on our experience. PMID:23686385

Dual THz comb spectroscopy

NASA Astrophysics Data System (ADS)

Yasui, Takeshi

2017-08-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Characterization of a commercial software defined radio as high frequency lock-in amplifier for FM spectroscopy.

PubMed

Mahnke, Peter

2018-01-01

A commercial software defined radio based on a Rafael Micro R820T2 tuner is characterized for the use as a high-frequency lock-in amplifier for frequency modulation spectroscopy. The sensitivity limit of the receiver is 1.6 nV/Hz. Frequency modulation spectroscopy is demonstrated on the 6406.69 cm -1 absorption line of carbon monoxide.

Characterization of a commercial software defined radio as high frequency lock-in amplifier for FM spectroscopy

NASA Astrophysics Data System (ADS)

Mahnke, Peter

2018-01-01

A commercial software defined radio based on a Rafael Micro R820T2 tuner is characterized for the use as a high-frequency lock-in amplifier for frequency modulation spectroscopy. The sensitivity limit of the receiver is 1.6 nV/√{Hz }. Frequency modulation spectroscopy is demonstrated on the 6406.69 cm-1 absorption line of carbon monoxide.

Application of Laser Induced Breakdown Spectroscopy under Polar Conditions

NASA Astrophysics Data System (ADS)

Clausen, J. L.; Hark, R.; Bol'shakov, A.; Plumer, J.

2015-12-01

Over the past decade our research team has evaluated the use of commercial-off-the-shelf laser-induced breakdown spectroscopy (LIBS) for chemical analysis of snow and ice samples under polar conditions. One avenue of research explored LIBS suitability as a detector of paleo-climate proxy indicators (Ca, K, Mg, and Na) in ice as it relates to atmospheric circulation. LIBS results revealed detection of peaks for C and N, consistent with the presence of organic material, as well as major ions (Ca, K, Mg, and Na) and trace metals (Al, Cu, Fe, Mn, Ti). The detection of Ca, K, Mg, and Na confirmed that LIBS has sufficient sensitivity to be used as a tool for characterization of paleo-climate proxy indicators in ice-core samples. Techniques were developed for direct analysis of ice as well as indirect measurements of ice via melting and filtering. Pitfalls and issues of direct ice analysis using several cooling techniques to maintain ice integrity will be discussed. In addition, a new technique, laser ablation molecular isotopic spectroscopy (LAMIS) was applied to detection of hydrogen and oxygen isotopes in ice as isotopic analysis of ice is the main tool in paleoclimatology and glaciology studies. Our results demonstrated that spectra of hydroxyl isotopologues 16OH, 18OH, and 16OD can be recorded with a compact spectrograph to determine hydrogen and oxygen isotopes simultaneously. Quantitative isotopic calibration for ice analysis can be accomplished using multivariate chemometric regression as previously realized for water vapor. Analysis with LIBS and LAMIS required no special sample preparation and was about ten times faster than analysis using ICP-MS. Combination of the two techniques in one portable instrument for in-field analysis appears possible and would eliminate the logistical and cost issues associated with ice core management.

Estimation of different source contributions to sediment organic matter in an agricultural-forested watershed using end member mixing analyses based on stable isotope ratios and fluorescence spectroscopy.

PubMed

Derrien, Morgane; Kim, Min-Seob; Ock, Giyoung; Hong, Seongjin; Cho, Jinwoo; Shin, Kyung-Hoon; Hur, Jin

2018-03-15

The two popular source tracing tools of stable isotope ratios (δ 13 C and δ 15 N) and fluorescence spectroscopy were used to estimate the relative source contributions to sediment organic matter (SeOM) at five different river sites in an agricultural-forested watershed (Soyang Lake watershed), and their capabilities for the source assignment were compared. Bulk sediments were used for the stable isotopes, while alkaline extractable organic matter (AEOM) from sediments was used to obtain fluorescent indices for SeOM. Several source discrimination indices were fully compiled for a range of the SeOM sources distributed in the catchments of the watershed, which included soils, forest leaves, crop (C3 and C4) and riparian plants, periphyton, and organic fertilizers. The relative source contributions to the river sediment samples were estimated via end member mixing analysis (EMMA) based on several selected discrimination indices. The EMMA based on the isotopes demonstrated that all sediments were characterized by a medium to a high contribution of periphyton ranging from ~30% to 70% except for one site heavily affected by forest and agricultural fields with relatively high contributions of terrestrial materials. The EMMA based on fluorescence parameters, however, did not show similar results with low contributions from forest leaf and periphyton. The characteristics of the studied watershed were more consistent with the source contributions determined by the isotope ratios. The discrepancy in the EMMA capability for source assignments between the two analytical tools can be explained by the limited analytical window of fluorescence spectroscopy for non-fluorescent dissolved organic matter (FDOM) and the inability of AEOM to represent original bulk particulate organic matter (POM). Copyright © 2017 Elsevier B.V. All rights reserved.

The characterization of hydroxypropyl methylcellulose through the analysis of its substituents

USDA-ARS?s Scientific Manuscript database

The methyl and hydroxypropyl substituents in hydroxypropyl methylcellulose (HPMC) affect the resulting gel properties. These substituents in five HPMC gels were characterized using Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, small-amplitude oscillatory shear measurements, a...

Surface analysis of gold nanoparticles functionalized with thiol-modified glucose SAMs for biosensor applications.

NASA Astrophysics Data System (ADS)

Spampinato, Valentina; Parracino, Mariaantonietta; La Spina, Rita; Rossi, Francois; Ceccone, Giacomo

2016-02-01

In this work, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Principal Component Analysis (PCA) and X-ray Photoelectron Spectroscopy (XPS) have been used to characterize the surface chemistry of gold substrates before and after functionalization with thiol-modified glucose self-assembled monolayers and subsequent biochemical specific recognition of maltose binding protein (MBP). The results indicate that the surface functionalization is achieved both on flat and nanoparticles gold substrates thus showing the potential of the developed system as biodetection platform. Moreover, the method presented here has been found to be a sound and valid approach to characterize the surface chemistry of nanoparticles functionalized with large molecules. Both techniques were proved to be very useful tools for monitoring all the functionalization steps, including the investigation of the biological behaviour of the glucose-modified particles in presence of the maltose binding protein.

Label-Free Imaging and Biochemical Characterization of Bovine Sperm Cells

PubMed Central

Ferrara, Maria Antonietta; Di Caprio, Giuseppe; Managò, Stefano; De Angelis, Annalisa; Sirleto, Luigi; Coppola, Giuseppe; De Luca, Anna Chiara

2015-01-01

A full label-free morphological and biochemical characterization is desirable to select spermatozoa during preparation for artificial insemination. In order to study these fundamental parameters, we take advantage of two attractive techniques: digital holography (DH) and Raman spectroscopy (RS). DH presents new opportunities for studying morphological aspect of cells and tissues non-invasively, quantitatively and without the need for staining or tagging, while RS is a very specific technique allowing the biochemical analysis of cellular components with a spatial resolution in the sub-micrometer range. In this paper, morphological and biochemical bovine sperm cell alterations were studied using these techniques. In addition, a complementary DH and RS study was performed to identify X- and Y-chromosome-bearing sperm cells. We demonstrate that the two techniques together are a powerful and highly efficient tool elucidating some important criterions for sperm morphological selection and sex-identification, overcoming many of the limitations associated with existing protocols. PMID:25836358

X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

NASA Astrophysics Data System (ADS)

Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

2007-10-01

The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

Surface Analysis of Gold Nanoparticles Functionalized with Thiol-Modified Glucose SAMs for Biosensor Applications

PubMed Central

Spampinato, Valentina; Parracino, Maria Antonietta; La Spina, Rita; Rossi, Francois; Ceccone, Giacomo

2016-01-01

In this work, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Principal Component Analysis (PCA) and X-ray Photoelectron Spectroscopy (XPS) have been used to characterize the surface chemistry of gold substrates before and after functionalization with thiol-modified glucose self-assembled monolayers and subsequent biochemical specific recognition of maltose binding protein (MBP). The results indicate that the surface functionalization is achieved both on flat and nanoparticles gold substrates thus showing the potential of the developed system as biodetection platform. Moreover, the method presented here has been found to be a sound and valid approach to characterize the surface chemistry of nanoparticles functionalized with large molecules. Both techniques were proved to be very useful tools for monitoring all the functionalization steps, including the investigation of the biological behavior of the glucose-modified particles in the presence of the maltose binding protein. PMID:26973830

Thermodynamic and structural characterization of an antibody gel

PubMed Central

Esue, Osigwe; Xie, Anna X.; Kamerzell, Tim J.; Patapoff, Thomas W.

2013-01-01

Although extensively studied, protein–protein interactions remain highly elusive and are of increasing interest in drug development. We show the assembly of a monoclonal antibody, using multivalent carboxylate ions, into highly-ordered structures. While the presence and function of similar structures in vivo are not known, the results may present a possible unexplored area of antibody structure-function relationships. Using a variety of tools (e.g., mechanical rheology, electron microscopy, isothermal calorimetry, Fourier transform infrared spectroscopy), we characterized the physical, biochemical, and thermodynamic properties of these structures and found that citrate may interact directly with the amino acid residue histidine, after which the individual protein units assemble into a filamentous network gel exhibiting high elasticity and interfilament interactions. Citrate interacts exothermically with the monoclonal antibody with an association constant that is highly dependent on solution pH and temperature. Secondary structure analysis also reveals involvement of hydrophobic and aromatic residues. PMID:23425660

Microwave platform as a valuable tool for characterization of nanophotonic devices

PubMed Central

Shishkin, Ivan; Baranov, Dmitry; Slobozhanyuk, Alexey; Filonov, Dmitry; Lukashenko, Stanislav; Samusev, Anton; Belov, Pavel

2016-01-01

The rich potential of the microwave experiments for characterization and optimization of optical devices is discussed. While the control of the light fields together with their spatial mapping at the nanoscale is still laborious and not always clear, the microwave setup allows to measure both amplitude and phase of initially determined magnetic and electric field components without significant perturbation of the near-field. As an example, the electromagnetic properties of an add-drop filter, which became a well-known workhorse of the photonics, is experimentally studied with the aid of transmission spectroscopy measurements in optical and microwave ranges and through direct mapping of the near fields at microwave frequencies. We demonstrate that the microwave experiments provide a unique platform for the comprehensive studies of electromagnetic properties of micro- and nanophotonic devices, and allow to obtain data which are hardly acquirable by conventional optical methods. PMID:27759058

CHARACTERIZATION OF METABOLITES IN SMALL FISH BIOFLUIDS AND TISSUES BY NMR SPECTROSCOPY

EPA Science Inventory

Nuclear magnetic resonance (NMR) spectroscopy has been utilized for assessing ecotoxicity in small fish models by means of metabolomics. Two fundamental challenges of NMR-based metabolomics are the detection limit and characterization of metabolites (or NMR resonance assignments...

The 14th Annual James L. Waters Symposium at Pittcon: Raman Spectroscopy

ERIC Educational Resources Information Center

Gardner, Charles W.

2007-01-01

Raman Spectroscopy was the main topic of the 14th Annual James L. Waters Symposium, which was held in March 2003 at Pittcon. The development of the enabling technologies that have made Raman spectroscopy a routine analysis tool in many laboratories worldwide is discussed.

Teaching UV-Vis Spectroscopy with a 3D-Printable Smartphone Spectrophotometer

ERIC Educational Resources Information Center

Grasse, Elise K.; Torcasio, Morgan H.; Smith, Adam W.

2016-01-01

Visible absorbance spectroscopy is a widely used tool in chemical, biochemical, and medical laboratories. The theory and methods of absorbance spectroscopy are typically introduced in upper division undergraduate chemistry courses, but could be introduced earlier with the right curriculum and instrumentation. A major challenge in teaching…

An Inorganic Laboratory Experiment Involving Photochemistry, Liquid Chromatography, and Infrared Spectroscopy.

ERIC Educational Resources Information Center

Post, Elroy W.

1980-01-01

Presents an experiment involving photochemical legand displacement on a metal carbonyl, separation of the product mixture by chromotography, and identification of the components by use of infrared spectroscopy and group theory. The chromatography and spectroscopy are combined as complementary tools in this experiment. (Author/JN)

Vibrational Micro-Spectroscopy of Human Tissues Analysis: Review.

PubMed

Bunaciu, Andrei A; Hoang, Vu Dang; Aboul-Enein, Hassan Y

2017-05-04

Vibrational spectroscopy (Infrared (IR) and Raman) and, in particular, micro-spectroscopy and micro-spectroscopic imaging have been used to characterize developmental changes in tissues, to monitor these changes in cell cultures and to detect disease and drug-induced modifications. The conventional methods for biochemical and histophatological tissue characterization necessitate complex and "time-consuming" sample manipulations and the results are rarely quantifiable. The spectroscopy of molecular vibrations using mid-IR or Raman techniques has been applied to samples of human tissue. This article reviews the application of these vibrational spectroscopic techniques for analysis of biological tissue published between 2005 and 2015.

Gas-phase broadband spectroscopy using active sources: progress, status, and applications

PubMed Central

Cossel, Kevin C.; Waxman, Eleanor M.; Finneran, Ian A.; Blake, Geoffrey A.; Ye, Jun; Newbury, Nathan R.

2017-01-01

Broadband spectroscopy is an invaluable tool for measuring multiple gas-phase species simultaneously. In this work we review basic techniques, implementations, and current applications for broadband spectroscopy. We discuss components of broad-band spectroscopy including light sources, absorption cells, and detection methods and then discuss specific combinations of these components in commonly-used techniques. We finish this review by discussing potential future advances in techniques and applications of broad-band spectroscopy. PMID:28630530

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.

Extended germa[N]pericyclynes: synthesis and characterization.

PubMed

Tanimoto, Hiroki; Fujiwara, Taro; Mori, Junta; Nagao, Tomohiko; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Ito, Shunichiro; Tanaka, Kazuo; Chujo, Yoshiki; Kakiuchi, Kiyomi

2017-02-14

We herein describe the syntheses and characterization of extended germa[N]pericyclynes, which are macrocycles composed of germanium-butadiyne units. The obtained novel extended germa[4]-[8]pericyclynes were characterized by X-ray crystallography, UV-Vis spectroscopy, fluorescence and phosphorescence emission spectroscopy, and cyclic voltammetry, and exhibited characteristic absorptions and emissions. Density functional theory (DFT) calculations suggested smaller HOMO-LUMO gap energy compared to that of general germapericyclynes.

Why Raman Spectroscopy on Mars?-A Case of the Right Tool for the Right Job

NASA Astrophysics Data System (ADS)

Ellery, Alex; Wynn-Williams, David

2003-11-01

We provide a scientific rationale for the astrobiological investigation of Mars. We suggest that, given practical constraints, the most promising locations for the search for former life on Mars are palaeolake craters and the evaporite deposits that may reside within them. We suggest that Raman spectroscopy offers a promising tool for the detection of evidence of former (or extant) biota on Mars. In particular, we highlight the detection of hopanoids as long-lived bacterial cell wall products and photosynthetic pigments as the most promising targets. We further suggest that Raman spectroscopy as a fibre optic-based instrument lends itself to flexible planetary deployment.

Analysis of disulphide bonds found in human hair by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Pina-Ruiz, A. L.; Cordova-Fraga, T.; Plascencia-Castro, A. S.; Hernandez-Rayas, A.; Ruvalcaba, J. M.

2017-04-01

Raman spectroscopy offers information-rich spectra, making it a technique easy to use in areas such as biology, chemistry, and in the field. Human hair spectra has been recorded obtaining interesting information about its composition. Correlating information obtained from these spectra to bone health and determining if Raman spectroscopy could be used as a diagnostic tool of bone health is proposed. Spectra from healthy women were compared to the spectra of women who have suffered a bone fracture, all which were aged 39-60. This technique has potential to become a regular diagnostic tool and further investigation to improve and validate this method are needed.

Why Raman spectroscopy on Mars?--a case of the right tool for the right job.

PubMed

Ellery, Alex; Wynn-Williams, David

2003-01-01

We provide a scientific rationale for the astrobiological investigation of Mars. We suggest that, given practical constraints, the most promising locations for the search for former life on Mars are palaeolake craters and the evaporite deposits that may reside within them. We suggest that Raman spectroscopy offers a promising tool for the detection of evidence of former (or extant) biota on Mars. In particular, we highlight the detection of hopanoids as long-lived bacterial cell wall products and photosynthetic pigments as the most promising targets. We further suggest that Raman spectroscopy as a fibre optic-based instrument lends itself to flexible planetary deployment.

Assessment of Anterior Cingulate Cortex (ACC) and Left Cerebellar Metabolism in Asperger's Syndrome with Proton Magnetic Resonance Spectroscopy (MRS).

PubMed

Goji, Aya; Ito, Hiromichi; Mori, Kenji; Harada, Masafumi; Hisaoka, Sonoka; Toda, Yoshihiro; Mori, Tatsuo; Abe, Yoko; Miyazaki, Masahito; Kagami, Shoji

2017-01-01

Proton magnetic resonance spectroscopy (1H MRS) is a noninvasive neuroimaging method to quantify biochemical metabolites in vivo and it can serve as a powerful tool to monitor neurobiochemical profiles in the brain. Asperger's syndrome (AS) is a type of autism spectrum disorder, which is characterized by impaired social skills and restrictive, repetitive patterns of interest and activities, while intellectual levels and language skills are relatively preserved. Despite clinical aspects have been well-characterized, neurometabolic profiling in the brain of AS remains to be clear. The present study used proton magnetic resonance spectroscopy (1H MRS) to investigate whether pediatric AS is associated with measurable neurometabolic abnormalities that can contribute new information on the neurobiological underpinnings of the disorder. Study participants consisted of 34 children with AS (2-12 years old; mean age 5.2 (±2.0); 28 boys) and 19 typically developed children (2-11 years old; mean age 5.6 (±2.6); 12 boys) who served as the normal control group. The 1H MRS data were obtained from two regions of interest: the anterior cingulate cortex (ACC) and left cerebellum. In the ACC, levels of N-acetylaspartate (NAA), total creatine (tCr), total choline-containing compounds (tCho) and myo-Inositol (mI) were significantly decreased in children with AS compared to controls. On the other hand, no significant group differences in any of the metabolites were found in the left cerebellum. Neither age nor sex accounted for the metabolic findings in the regions. The finding of decreased levels of NAA, tCr, tCho, and mI in the ACC but not in left cerebellar voxels in the AS, suggests a lower ACC neuronal density in the present AS cohort compared to controls.

Green synthesis of chondroitin sulfate-capped silver nanoparticles: characterization and surface modification.

PubMed

Cheng, Kuang-ming; Hung, Yao-wen; Chen, Cheng-cheung; Liu, Cheng-che; Young, Jenn-jong

2014-09-22

A one-step route for the green synthesis of highly stable and nanosized silver metal particles with narrow distribution is reported. In this environmentally friendly synthetic method, silver nitrate was used as silver precursor and biocompatible chondroitin sulfate (ChS) was used as both reducing agent and stabilizing agent. The reaction was carried out in a stirring aqueous medium at the room temperature without any assisted by microwave, autoclave, laser irradiation, γ-ray irradiation or UV irradiation. The transparent colorless solution was converted to the characteristics light red then deep red-brown color as the reaction proceeds, indicating the formation of silver nanoparticles (Ag NPs). The Ag NPs were characterized by UV-visible spectroscopy (UV-vis), photon correlation spectroscopy, laser Doppler anemometry, transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were Ag NPs capped with ChS. In this report, dynamic light scattering (DLS) was used as a routinely analytical tool for measuring size and distribution in a liquid environment. The effects of the reaction time, reaction temperature, concentration and the weight ratio of ChS/Ag+ on the particle size and zeta potential were investigated. The TEM image clearly shows the morphology of the well-dispersed ChS-capped Ag NPs are spherical in shape, and the average size (<20 nm) is much smaller than the Z-average value (76.7 nm) measured by DLS. Meanwhile, the ChS-capped Ag NPs coated with N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) were prepared by an ionic gelation method and the surface charge of Ag NPs was switched from negative to positive. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tunneling mechanism and contact mechanics of colloidal nanoparticle assemblies.

PubMed

Biaye, Moussa; Zbydniewska, Ewa; Mélin, Thierry; Deresmes, Dominique; Copie, Guillaume; Cleri, Fabrizio; Sangeetha, Neralagatta; Decorde, Nicolas; Viallet, Benoit; Grisolia, Jérémie; Ressier, Laurence; Diesinger, Heinrich

2016-11-25

Nanoparticle assemblies with thiol-terminated alkyl chains are studied by conducting atomic force microscopy (c-AFM) regarding their use as strain gauges for touch-sensitive panels. Current-force spectroscopy is used as a characterization tool complementary to the macroscopic setup since it allows a bias to be applied to a limited number of junctions, overcoming the Coulomb blockade energy and focusing on the contact electromechanics and the transport mechanism across the ligand. First, transition voltage spectroscopy is applied with varying force to target the underlying tunneling mechanism by observing whether the transition between the ohmic and exponential current-voltage behavior is force-dependent. Secondly, current-force spectroscopy in the ohmic range below the transition voltage is performed. The current-force behavior of the AFM probe in contact with a nanoparticle multilayer is associated with the spread of force and current within the nanoparticle lattice and at the level of adjacent particles by detailed contact mechanics treatment. The result is twofold: concerning the architecture of sensors, this work is a sample case of contact electromechanics at scales ranging from the device scale down to the individual ligand molecule. Regarding transport across the molecule, the vacuum tunneling mechanism is favored over the conduction by coherent molecular states, which is a decision-making aid for the choice of ligand in applications.

Dual modality instrument for simultaneous optical coherence tomography imaging and fluorescence spectroscopy.

PubMed

Barton, Jennifer Kehlet; Guzman, Francisco; Tumlinson, Alexandre

2004-01-01

We develop a dual-modality device that combines the anatomical imaging capabilities of optical coherence tomography (OCT) with the functional capabilities of laser-induced fluorescence (LIF) spectroscopy. OCT provides cross-sectional images of tissue structure to a depth of up to 2 mm with approximately 10-microm resolution. LIF spectroscopy provides histochemical information in the form of emission spectra from a given tissue location. The OCT subsystem utilizes a superluminescent diode with a center wavelength of 1300 nm, whereas a helium cadmium laser provides the LIF excitation source at wavelengths of 325 and 442 nm. Preliminary data are obtained on eight postmortem aorta samples, each 10 mm in length. OCT images and LIF spectra give complementary information from normal and atherosclerotic portions of aorta wall. OCT images show structures such as intima, media, internal elastic lamina, and fibrotic regions. Emission spectra ratios of 520/490 (325-nm excitation) and 595/635 (442-nm excitation) could be used to identify normal and plaque regions with 97 and 91% correct classification rates, respectively. With miniaturization of the delivery probe and improvements in system speed, this dual-modality device could provide a valuable tool for identification and characterization of atherosclerotic plaques. (c) 2004 Society of Photo-Optical Instrumentation Engineers.

[Comparison of Three Spectroscopies for the Determination of Composition of LDPE/PP Blend with Partial Least-Squares].

PubMed

Chen, Ru-huang; Jin, Gang

2015-08-01

This paper presented an application of mid-infrared (MIR), near-infrared (NIR) and Raman spectroscopies for collecting the spectra of 31 kinds of low density polyethylene/polyprolene (LDPE/PP) samples with different proportions. The different pre-processing methods (multiplicative scatter correction, mean centering and Savitzky-Golay first derivative) and spectral region were explored to develop partial least-squares (PLS) model for LDPE, their influence on the accuracy of PLS model also being discussed. Three spectroscopies were compared about the accuracy of quantitative measurement. Consequently, the pre-processing methods and spectral region have a great impact on the accuracy of PLS model, especially the spectra with subtle difference, random noise and baseline variation. After being pre-processed and spectral region selected, the calibration model of MIR, NIR and Raman exhibited R2/RMSEC values of 0.9906/2.941, 0.9973/1.561 and 0.9972/1.598 respectively, which corrsponding to 0.8876/10.15, 0.8493/11.75 and 0.8757/10.67 before any treatment. The results also suggested MIR, NIR and Raman are three strong tools to predict the content of LDPE in LDPE/PP blend. However, NIR and Raman showed higher accuracy after being pre-processed and more suitability to fast quantitative characterization due to their high measuring speed.

Femtosecond laser ablation of bovine cortical bone

NASA Astrophysics Data System (ADS)

Cangueiro, Liliana T.; Vilar, Rui; Botelho do Rego, Ana M.; Muralha, Vania S. F.

2012-12-01

We study the surface topographical, structural, and compositional modifications induced in bovine cortical bone by femtosecond laser ablation. The tests are performed in air, with a Yb:KYW chirped-pulse-regenerative amplification laser system (500 fs, 1030 nm) at fluences ranging from 0.55 to 2.24 J/cm2. The ablation process is monitored by acoustic emission measurements. The topography of the laser-treated surfaces is studied by scanning electron microscopy, and their constitution is characterized by glancing incidence x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and micro-Raman spectroscopy. The results show that femtosecond laser ablation allows removing bone without melting, carbonization, or cracking. The structure and composition of the remaining tissue are essentially preserved, the only constitutional changes observed being a reduction of the organic material content and a partial recrystallization of hydroxyapatite in the most superficial region of samples. The results suggest that, within this fluence range, ablation occurs by a combination of thermal and electrostatic mechanisms, with the first type of mechanism predominating at lower fluences. The associated thermal effects explain the constitutional changes observed. We show that femtosecond lasers are a promising tool for delicate orthopaedic surgeries, where small amounts of bone must be cut with negligible damage, thus minimizing surgical trauma.

Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

DOE PAGES

Battaglieri, Marco; Briscoe, William; Celentano, Andrea; ...

2015-01-01

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopymore » in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.« less

Distinctive EPR signals provide an understanding of the affinity of bis-(3-hydroxy-4-pyridinonato) copper(II) complexes for hydrophobic environments.

PubMed

Rangel, Maria; Leite, Andreia; Silva, André M N; Moniz, Tânia; Nunes, Ana; Amorim, M João; Queirós, Carla; Cunha-Silva, Luís; Gameiro, Paula; Burgess, John

2014-07-07

In this work we report the synthesis and characterization of a set of 3-hydroxy-4-pyridinone copper(ii) complexes with variable lipophilicity. EPR spectroscopy was used to characterize the structure of copper(ii) complexes in solution, and as a tool to gain insight into solvent interactions. EPR spectra of solutions of the [CuL2] complexes recorded in different solvents reveal the presence of two copper species whose ratio depends on the nature of the solvent. Investigation of EPR spectra in the pure solvents methanol, dimethylsulfoxide, dichloromethane and their 50% (v/v) mixtures with toluene allowed the characterization of two types of copper signals (gzz = 2.30 and gzz = 2.26) whose spin-Hamiltonian parameters are consistent with solvated and non-solvated square-planar copper(ii) complexes. Regarding the potential biological application of ligands and complexes and to get insight into the partition properties in water-membrane interfaces, EPR spectra were also obtained in water-saturated octanol, an aqueous solution buffered at pH = 7.4 and liposome suspensions, for three compounds representative of different hydro-lipophilic balances. Analysis of the EPR spectra obtained in liposomes allowed establishment of the location of the complexes in the water and lipid phases. In view of the results of this work we put forward the use of EPR spectroscopy to assess the affinity of copper(ii) complexes for a hydrophobic environment and also to obtain indirect information about the lipophilicity of the ligands and similar EPR silent complexes.

Application Of Positron Beams For The Characterization Of Nano-scale Pores In Thin Films

NASA Astrophysics Data System (ADS)

Hirata, K.; Ito, K.; Kobayashi, Y.; Suzuki, R.; Ohdaira, T.; Eijt, S. W. H.; Schut, H.; van Veen, A.

2003-08-01

We applied three positron annihilation techniques, positron 3γ-annihilation spectroscopy, positron annihilation lifetime spectroscopy, and angular correlation of annihilation radiation, to the characterization of nano-scale pores in thin films by combining them with variable-energy positron beams. Characterization of pores in thin films is an important part of the research on various thin films of industrial importance. The results of our recent studies on pore characterization of thin films by positron beams will be reported here.

Various MRS application tools for Alzheimer disease and mild cognitive impairment.

PubMed

Gao, F; Barker, P B

2014-06-01

MR spectroscopy is a noninvasive technique that allows the detection of several naturally occurring compounds (metabolites) from well-defined regions of interest within the human brain. Alzheimer disease, a progressive neurodegenerative disorder, is the most common cause of dementia in the elderly. During the past 20 years, multiple studies have been performed on MR spectroscopy in patients with both mild cognitive impairment and Alzheimer disease. Generally, MR spectroscopy studies have found decreased N-acetylaspartate and increased myo-inositol in both patients with mild cognitive impairment and Alzheimer disease, with greater changes in Alzheimer disease than in mild cognitive impairment. This review summarizes the information content of proton brain MR spectroscopy and its related technical aspects, as well as applications of MR spectroscopy to mild cognitive impairment and Alzheimer disease. While MR spectroscopy may have some value in the differential diagnosis of dementias and assessing prognosis, more likely its role in the near future will be predominantly as a tool for monitoring disease response or progression in treatment trials. More work is needed to evaluate the role of MR spectroscopy as a biomarker in Alzheimer disease and its relationship to other imaging modalities. © 2014 by American Journal of Neuroradiology.

BATSE spectroscopy analysis system

NASA Technical Reports Server (NTRS)

Schaefer, Bradley E.; Bansal, Sandhia; Basu, Anju; Brisco, Phil; Cline, Thomas L.; Friend, Elliott; Laubenthal, Nancy; Panduranga, E. S.; Parkar, Nuru; Rust, Brad

1992-01-01

The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS.

Identification and characterization of new designer drug 4-fluoro-PV9 and α-PHP in the seized materials.

PubMed

Majchrzak, Milena; Rojkiewicz, Marcin; Celiński, Rafał; Kuś, Piotr; Sajewicz, Mieczysław

In this study, we present identification and physicochemical characterization of new cathinone derivatives, 4-fluoro-PV9 and already known α-PHP in seized materials. Although the disclosure of α-PHP from an illegal product had been reported and characterized to some extent, the data on α-PHP are also presented together with those of 4-fluoro-PV9. The data of characterization for the two compounds were obtained by high-performance liquid chromatography (HPLC)-mass spectrometry and HPLC-diode array detection, electrospray ionization/ion trap mass spectrometry in MS 2 and MS 3 modes, gas chromatography-mass spectrometry, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and nuclear magnetic resonance spectroscopy. To our knowledge, this is the first report for identification and detailed characterization of 4-fluoro-PV9 circulated on the illegal drug market.

Studies of the Si/SiO2 interface using synchrotron radiation

NASA Technical Reports Server (NTRS)

Hecht, M. H.; Grunthaner, F. J.

1985-01-01

Synchrotron radiation photoemission spectroscopy (SRPS) in the 1-4 KeV photon energy range is a useful tool for interface characterization. Results are presented of a series of studies of the near-interface region of Si/SiO2 which confirm that a bond strain gradient exists in the oxide as a result of lattice mismatch. These experiments include measurement of photoemission lineshape changes as a function of photon energy, corresponding changes in the electron escape depth near the interface, and surface extended X-ray absorption fine structure (SEXAFS) measurements directly indicating the shortening of the Si-Si second nearest neighbor distance in the near-interface region of the oxide.

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.

Biophotonic endoscopy: a review of clinical research techniques for optical imaging and sensing of early gastrointestinal cancer

PubMed Central

Coda, Sergio; Siersema, Peter D.; Stamp, Gordon W. H.; Thillainayagam, Andrew V.

2015-01-01

Detection, characterization, and staging constitute the fundamental elements in the endoscopic diagnosis of gastrointestinal diseases, but histology still remains the diagnostic gold standard. New developments in endoscopic techniques may challenge histopathology in the near future. An ideal endoscopic technique should combine a wide-field, “red flag” screening technique with an optical contrast or microscopy method for characterization and staging, all simultaneously available during the procedure. In theory, biophotonic advances have the potential to unite these elements to allow in vivo “optical biopsy.” These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients. However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology. This review describes some of the most recent applications of biophotonics in endoscopic optical imaging and metrology, along with their fundamental principles and the clinical experience that has been acquired in their deployment as tools for the endoscopist. Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging. PMID:26528489

Deposition and characterization of TiAlSiN nanocomposite coatings prepared by reactive pulsed direct current unbalanced magnetron sputtering

NASA Astrophysics Data System (ADS)

Barshilia, Harish C.; Ghosh, Moumita; Shashidhara; Ramakrishna, Raja; Rajam, K. S.

2010-08-01

This work reports the performance of high speed steel drill bits coated with TiAlSiN nanocomposite coating at different Si contents (5.5-8.1 at.%) prepared using a four-cathode reactive pulsed direct current unbalanced magnetron sputtering system. The surface morphology of the as-deposited coatings was characterized using field emission scanning electron microscopy. The crystallographic structure, chemical composition and bonding structure were evaluated using X-ray diffraction, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, respectively. The corrosion behavior, mechanical properties and thermal stability of TiAlSiN nanocomposite coatings were also studied using potentiodynamic polarization, nanoindentation and Raman spectroscopy, respectively. The TiAlSiN coating thickness was approximately 2.5-2.9 μm. These coatings exhibited a maximum hardness of 38 GPa at a silicon content of approximately 6.9 at.% and were stable in air up to 850 °C. For the performance evaluation, the TiAlSiN coated drills were tested under accelerated machining conditions by drilling a 12 mm thick 304 stainless steel plate. Under dry conditions the uncoated drill bits failed after drilling 50 holes, whereas, TiAlSiN coated drill bits (Si = 5.5 at.%) drilled 714 holes before failure. Results indicated that for TiAlSiN coated drill bits the tool life increased by a factor of more than 14.

X-ray absorption spectroscopy to watch catalysis by metalloenzymes: status and perspectives discussed for the water-splitting manganese complex of photosynthesis.

PubMed

Dau, Holger; Haumann, Michael

2003-01-01

Understanding structure-function relations is one of the main interests in the molecular biosciences. X-ray absorption spectroscopy of biological samples (BioXAS) has gained the status of a useful tool for characterization of the structure of protein-bound metal centers with respect to the electronic structure (oxidation states, orbital occupancies) and atomic structure (arrangement of ligand atoms). Owing to progress in the performance characteristics of synchrotron radiation sources and of experimental stations dedicated to the study of (ultra-dilute) biological samples, it is now possible to carry out new types of BioXAS experiments, which have been impracticable in the past. Of particular interest are approaches to follow biological catalysis at metal sites by characterization of functionally relevant structural changes. In this Article, the first steps towards the use of BioXAS to 'watch' biological catalysis are reviewed for the water-splitting reactions occurring at the manganese complex of photosynthesis. The following aspects are considered: the role of BioXAS in life sciences; methodological aspects of BioXAS; catalysis at the Mn complex of photosynthesis; combination of EXAFS and crystallographic information; the freeze-quench technique to capture semi-stable states; time-resolved BioXAS using a freeze-quench approach; room-temperature experiments and 'real-time' BioXAS; tasks and perspectives.

Characterization and correction of the false-discovery rates in resting state connectivity using functional near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Santosa, Hendrik; Aarabi, Ardalan; Perlman, Susan B.; Huppert, Theodore J.

2017-05-01

Functional near-infrared spectroscopy (fNIRS) is a noninvasive neuroimaging technique that uses low levels of red to near-infrared light to measure changes in cerebral blood oxygenation. Spontaneous (resting state) functional connectivity (sFC) has become a critical tool for cognitive neuroscience for understanding task-independent neural networks, revealing pertinent details differentiating healthy from disordered brain function, and discovering fluctuations in the synchronization of interacting individuals during hyperscanning paradigms. Two of the main challenges to sFC-NIRS analysis are (i) the slow temporal structure of both systemic physiology and the response of blood vessels, which introduces false spurious correlations, and (ii) motion-related artifacts that result from movement of the fNIRS sensors on the participants' head and can introduce non-normal and heavy-tailed noise structures. In this work, we systematically examine the false-discovery rates of several time- and frequency-domain metrics of functional connectivity for characterizing sFC-NIRS. Specifically, we detail the modifications to the statistical models of these methods needed to avoid high levels of false-discovery related to these two sources of noise in fNIRS. We compare these analysis procedures using both simulated and experimental resting-state fNIRS data. Our proposed robust correlation method has better performance in terms of being more reliable to the noise outliers due to the motion artifacts.

Enhanced Vibrational Spectroscopies as Tools for Small Molecule Biosensing

PubMed Central

Boujday, Souhir; Lamy de la Chapelle, Marc; Srajer, Johannes; Knoll, Wolfgang

2015-01-01

In this short summary we summarize some of the latest developments in vibrational spectroscopic tools applied for the sensing of (small) molecules and biomolecules in a label-free mode of operation. We first introduce various concepts for the enhancement of InfraRed spectroscopic techniques, including the principles of Attenuated Total Reflection InfraRed (ATR-IR), (phase-modulated) InfraRed Reflection Absorption Spectroscopy (IRRAS/PM-IRRAS), and Surface Enhanced Infrared Reflection Absorption Spectroscopy (SEIRAS). Particular attention is put on the use of novel nanostructured substrates that allow for the excitation of propagating and localized surface plasmon modes aimed at operating additional enhancement mechanisms. This is then be complemented by the description of the latest development in Surface- and Tip-Enhanced Raman Spectroscopies, again with an emphasis on the detection of small molecules or bioanalytes. PMID:26343666

From near-infrared and Raman to surface-enhanced Raman spectroscopy: progress, limitations and perspectives in bioanalysis.

PubMed

Dumont, Elodie; De Bleye, Charlotte; Sacré, Pierre-Yves; Netchacovitch, Lauranne; Hubert, Philippe; Ziemons, Eric

2016-05-01

Over recent decades, spreading environmental concern entailed the expansion of green chemistry analytical tools. Vibrational spectroscopy, belonging to this class of analytical tool, is particularly interesting taking into account its numerous advantages such as fast data acquisition and no sample preparation. In this context, near-infrared, Raman and mainly surface-enhanced Raman spectroscopy (SERS) have thus gained interest in many fields including bioanalysis. The two former techniques only ensure the analysis of concentrated compounds in simple matrices, whereas the emergence of SERS improved the performances of vibrational spectroscopy to very sensitive and selective analyses. Complex SERS substrates were also developed enabling biomarker measurements, paving the way for SERS immunoassays. Therefore, in this paper, the strengths and weaknesses of these techniques will be highlighted with a focus on recent progress.

[Application of Fourier transform attenuated total reflection infrared spectroscopy in analysis of pulp and paper industry].

PubMed

Zhang, Yong; Cao, Chun-yu; Feng, Wen-ying; Xu, Ming; Su, Zhen-hua; Liu, Xiao-meng; Lü, Wei-jun

2011-03-01

As one of the most powerful tools to investigate the compositions of raw materials and the property of pulp and paper, infrared spectroscopy has played an important role in pulp and paper industry. However, the traditional transmission infrared spectroscopy has not met the requirements of the producing processes because of its disadvantages of time consuming and sample destruction. New technique would be needed to be found. Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) is an advanced spectroscopic tool for nondestructive evaluation and could rapidly, accurately estimate the production properties of each process in pulp and paper industry. The present review describes the application of ATR-FTIR in analysis of pulp and paper industry. The analysis processes will include: pulping, papermaking, environmental protecting, special processing and paper identifying.

Characterizing fiber-reinforced composite structures using AC-impedance spectroscopy (AC-IS)

NASA Astrophysics Data System (ADS)

Woo, Leta Y.

Property enhancement in composites depends largely on the reinforcement. For fiber-reinforced composites, the distribution of fibers is crucial in determining the electrical and mechanical performance. Image analysis methods for characterization can be time-consuming and/or destructive. This work explores the capability of AC-impedance spectroscopy (AC-IS), an electrical measurement technique, to serve as a rapid, non-destructive tool for characterizing composite microstructure. The composite requirements include a filler that is electrically conducting or semi-conducting with higher conductivity than the matrix, and a high-impedance interface or coating between the filler and the matrix. To establish an AC-IS characterization method, cement-matrix composites with steel reinforcement were employed as both a technologically important and a model system to investigate how fibers affect the electrical response. Beginning with spherical particulates and then fibers, composites were examined using composite theory and an "intrinsic conductivity" approach. The intrinsic conductivity approach applies to composites with low volume fractions of fibers (i.e., in the dilute regime) and relates how the composite conductivity varies relative to the matrix as a function of volume fraction. A universal equivalent circuit model was created to understand the AC-IS response of composites based on the geometry and volume fraction of the filler. Deviation from predicted behavior was assessed using a developed f-function, which quantifies how fibers contribute to the overall electrical response of the composite. Using the f-function, an AC-IS method for investigating fiber dispersion was established to characterize alignment, settling/segregation, and aggregation. Alignment was investigated using measurements made in three directions. A point-probe technique characterized settling and/or large-scale inhomogeneous mixing in samples. Aggregation was quantified using a "dispersion factor" that compared theoretical with measured values and served as an upper limit for how well the fibers were dispersed. The AC-IS method was then extended to two different cement-matrix composite systems, low resistivity fresh-paste cement composites (confirmed by time domain reflectometry) and high resistivity cement composites, both of which required additional analysis to apply the AC-IS characterization method.

Univariate and multivariate analysis of tannin-impregnated wood species using vibrational spectroscopy.

PubMed

Schnabel, Thomas; Musso, Maurizio; Tondi, Gianluca

2014-01-01

Vibrational spectroscopy is one of the most powerful tools in polymer science. Three main techniques--Fourier transform infrared spectroscopy (FT-IR), FT-Raman spectroscopy, and FT near-infrared (NIR) spectroscopy--can also be applied to wood science. Here, these three techniques were used to investigate the chemical modification occurring in wood after impregnation with tannin-hexamine preservatives. These spectroscopic techniques have the capacity to detect the externally added tannin. FT-IR has very strong sensitivity to the aromatic peak at around 1610 cm(-1) in the tannin-treated samples, whereas FT-Raman reflects the peak at around 1600 cm(-1) for the externally added tannin. This high efficacy in distinguishing chemical features was demonstrated in univariate analysis and confirmed via cluster analysis. Conversely, the results of the NIR measurements show noticeable sensitivity for small differences. For this technique, multivariate analysis is required and with this chemometric tool, it is also possible to predict the concentration of tannin on the surface.

Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs

PubMed Central

Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

2014-01-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10−7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy. PMID:24448604

Laminated helmet materials characterization by terahertz kinetics spectroscopy

NASA Astrophysics Data System (ADS)

Rahman, Anis; Rahman, Aunik K.

2015-05-01

High speed acquisition of reflected terahertz energy constitutes a kinetics spectrum that is an effective tool for layered materials' deformation characterization under ballistic impact. Here we describe utilizing the kinetics spectrum for quantifying a deformation event due to impact in material used for Soldier's helmet. The same technique may be utilized for real-time assessment of trauma by measuring the helmet wore by athletes. The deformation of a laminated material (e.g., a helmet) is dependent on the nature of impact and projectile; thus can uniquely characterize the impact condition leading to a diagnostic procedure based on the energy received by an athlete during an impact. We outline the calibration process for a given material under ballistic impact and then utilize the calibration for extracting physical parameters from the measured kinetics spectrum. Measured kinetics spectra are used to outline the method and rationale for extending the concept to a diagnosis tool. In particular, captured kinetics spectra from multilayered plates subjected to ballistic hit under experimental conditions by high speed digital acquisition system. An algorithm was devised to extract deformation and deformation velocity from which the energy received on the skull was estimated via laws of nonrelativistic motion. This energy is assumed to be related to actual injury conditions, thus forming a basis for determining whether the hit would cause concussion, trauma, or stigma. Such quantification may be used for diagnosing a Soldier's trauma condition in the field or that of an athlete's.

Multi-faceted characterization of battery reactions: the case of spinel hosts for Mg-ion batteries

NASA Astrophysics Data System (ADS)

Cabana, Jordi

2015-03-01

Electrochemical energy storage was an important enabler of the wireless revolution and it is touted as a key component of a society that shifts away from its dependence on fossil fuels. Batteries are the primary technology when high energy devices are required. They are complex reactors in which multiple physico-chemical phenomena are concurrent in time and space. As a result, it is increasingly clear that holistic approaches to define such phenomena require a breadth of characterization tools. I will exemplify this need in the context of our quest for hosts that are able to reversibly intercalate Mg2+ ions. Systems based on the intercalation of multivalent ions are pushed as next generation devices because, while they can resemble systems using Li+ ions, they can store more charge per mol of intercalated species, and adopt metals as the anode. Using a combination of characterization tools, including X-ray diffraction, spectroscopy and scattering, electron microscopy and nuclear magnetic resonance, we ascertained that spinel oxides are able to reversibly and extensively accommodate Mg2+. The mechanisms of this reaction were also elucidated. The rationale for the choice of techniques and the key pieces they provided to complete the picture will be discussed. This work was supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Molecular and Nanoscale Engineering of High Efficiency Excitonic Solar Cells

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

Jenekhe, Samson A.; Ginger, David S.; Cao, Guozhong

We combined the synthesis of new polymers and organic-inorganic hybrid materials with new experimental characterization tools to investigate bulk heterojunction (BHJ) polymer solar cells and hybrid organic-inorganic solar cells during the 2007-2010 period (phase I) of this project. We showed that the bulk morphology of polymer/fullerene blend solar cells could be controlled by using either self-assembled polymer semiconductor nanowires or diblock poly(3-alkylthiophenes) as the light-absorbing and hole transport component. We developed new characterization tools in-house, including photoinduced absorption (PIA) spectroscopy, time-resolved electrostatic force microscopy (TR-EFM) and conductive and photoconductive atomic force microscopy (c-AFM and pc-AFM), and used them to investigatemore » charge transfer and recombination dynamics in polymer/fullerene BHJ solar cells, hybrid polymer-nanocrystal (PbSe) devices, and dye-sensitized solar cells (DSSCs); we thus showed in detail how the bulk photovoltaic properties are connected to the nanoscale structure of the BHJ polymer solar cells. We created various oxide semiconductor (ZnO, TiO 2) nanostructures by solution processing routes, including hierarchical aggregates and nanorods/nanotubes, and showed that the nanostructured photoanodes resulted in substantially enhanced light-harvesting and charge transport, leading to enhanced power conversion efficiency of dye-sensitized solar cells.« less

Infrared Spectroscopy as a Versatile Analytical Tool for the Quantitative Determination of Antioxidants in Agricultural Products, Foods and Plants

PubMed Central

Cozzolino, Daniel

2015-01-01

Spectroscopic methods provide with very useful qualitative and quantitative information about the biochemistry and chemistry of antioxidants. Near infrared (NIR) and mid infrared (MIR) spectroscopy are considered as powerful, fast, accurate and non-destructive analytical tools that can be considered as a replacement of traditional chemical analysis. In recent years, several reports can be found in the literature demonstrating the usefulness of these methods in the analysis of antioxidants in different organic matrices. This article reviews recent applications of infrared (NIR and MIR) spectroscopy in the analysis of antioxidant compounds in a wide range of samples such as agricultural products, foods and plants. PMID:26783838

Balloon and Button Spectroscopy: A Hands-On Approach to Light and Matter

ERIC Educational Resources Information Center

Ribaudo, Joseph

2016-01-01

Without question, one of the most useful tools an astronomer or physicist can employ to study the universe is spectroscopy. However, for students in introductory physics or astronomy classes, spectroscopy is a relatively abstract concept that combines new physics topics such as thermal radiation, atomic physics, and the wave and particle nature of…

Single-molecule force spectroscopy: optical tweezers, magnetic tweezers and atomic force microscopy

PubMed Central

Neuman, Keir C.; Nagy, Attila

2012-01-01

Single-molecule force spectroscopy has emerged as a powerful tool to investigate the forces and motions associated with biological molecules and enzymatic activity. The most common force spectroscopy techniques are optical tweezers, magnetic tweezers and atomic force microscopy. These techniques are described and illustrated with examples highlighting current capabilities and limitations. PMID:18511917

Green synthesis and characterization of novel gold nanocomposites for electrochemical sensing applications.

PubMed

Tanwar, Shivani; Ho, Ja-an Annie; Magi, Emanuele

2013-12-15

Synthesis, characterization and application of Au-PANI-Calix and Au-PANI-Nap nanocomposites, is reported herein. An easy template free green synthesis is proposed and discussed for easy expediency. A variety of analytical techniques were used to characterize the nanocomposites: UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Dynamic light scattering (DLS), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to characterize the nanocomposites. Surface morphology was studied by transmission electron microscopy (TEM). The nanocomposites were immobilized on screen-printed electrode and showed electroactivity in neutral pH, making them promising candidates for various analytical applications. A sensitive and selective detection of Cu(2+) was perceived on the Au-PANI-Calix modified electrode with no interference from ions K(+), Ni(2+), Co(2+), Pb(2+), Cr(3+) with a detection limit of 10nM. The copper detection is facilitated for accessible ligation with 4-sulfocalix[4]arene, so as the Cu(II)-Calix complex formed. The electrode modified with Au-PANI-Nap showed sensing application towards H2O2 with a detection limit of 1 μM. The modified electrodes were reproducible and stable for 2 months. © 2013 Elsevier B.V. All rights reserved.

Fluorescence Correlation Spectroscopy to find the critical balance between extracellular association and intracellular dissociation of mRNA-complexes.

PubMed

Zhang, Heyang; De Smedt, Stefaan C; Remaut, Katrien

2018-05-10

Fluorescence Correlation Spectroscopy (FCS) is a promising tool to study interactions on a single molecule level. The diffusion of fluorescent molecules in and out of the excitation volume of a confocal microscope leads to the fluorescence fluctuations that give information on the average number of fluorescent molecules present in the excitation volume and their diffusion coefficients. In this context, we complexed mRNA into lipoplexes and polyplexes and explored the association/dissociation degree of complexes by using gel electrophoresis and FCS. FCS enabled us to measure the association and dissociation degree of mRNA-based complexes both in buffer and protein-rich biological fluids such as human serum and ascitic fluid, which is a clear advantage over gel electrophoresis that was only applicable in protein-free buffer solutions. Furthermore, following the complex stability in buffer and biological fluids by FCS assisted to understand how complex characteristics, such as charge ratio and strength of mRNA binding, correlated to the transfection efficiency. We found that linear polyethyleneimine prevented efficient translation of mRNA, most likely due to a too strong mRNA binding, whereas the lipid based carrier Lipofectamine ® messengerMAX did succeed in efficient release and subsequent translation of mRNA in the cytoplasm of the cells. Overall, FCS is a reliable tool for the in depth characterization of mRNA complexes and can help us to find the critical balance keeping mRNA bound in complexes in the extracellular environment and efficient intracellular mRNA release leading to protein production. The delivery of messenger RNA (mRNA) to cells is promising to treat a variety of diseases. Therefore, the mRNA is typically packed in small lipid particles or polymer particles that help the mRNA to reach the cytoplasm of the cells. These particles should bind and carry the mRNA in the extracellular environment (e.g. blood, peritoneal fluid, ...), but should release the mRNA again in the intracellular environment. In this paper, we evaluated a method (Fluorescence Correlation Spectroscopy) that allows for the in depth characterization of mRNA complexes and can help us to find the critical balance keeping mRNA bound in complexes in the extracellular environment and efficient intracellular mRNA release leading to protein production. Copyright © 2018. Published by Elsevier Ltd.

The use of analytical surface tools in the fundamental study of wear. [atomic nature of wear

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1977-01-01

Various techniques and surface tools available for the study of the atomic nature of the wear of materials are reviewed These include chemical etching, x-ray diffraction, electron diffraction, scanning electron microscopy, low-energy electron diffraction, Auger emission spectroscopy analysis, electron spectroscopy for chemical analysis, field ion microscopy, and the atom probe. Properties of the surface and wear surface regions which affect wear, such as surface energy, crystal structure, crystallographic orientation, mode of dislocation behavior, and cohesive binding, are discussed. A number of mechanisms involved in the generation of wear particles are identified with the aid of the aforementioned tools.

Characterization of lipid oxidation process of beef during repeated freeze-thaw by electron spin resonance technology and Raman spectroscopy.

PubMed

Chen, Qingmin; Xie, Yunfei; Xi, Jinzhong; Guo, Yahui; Qian, He; Cheng, Yuliang; Chen, Yi; Yao, Weirong

2018-03-15

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (P<0.05) after RFT. This suggested that lipid oxidation was occurred during RFT. With the increase of radical signal intensity, lower oxidation stability was presented by ESR. Raman intensity of ν(CC) stretching region (1655cm -1 ) was decreased during RFT. Furthermore, lower Raman intensity ratio of I 1655 /I 1442 , I 1655 /I 1745 that determine total unsaturation was also observed. Significant correlations (p<0.01) were obtained among conventional methods, ESR and Raman spectroscopy. Our result has proved that ESR and Raman spectroscopy showed great potential in characterizing lipid oxidation process of beef during RFT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Developing Raman spectroscopy for the nondestructive testing of composite materials.

DOT National Transportation Integrated Search

2009-08-01

The proposed research will develop the application of Raman Spectroscopy as a nondestructive evaluation tool for the condition assessment of carbon fiber composites. Composite materials are increasingly being used in engineered structures and compone...

Quantitative Raman spectroscopy as a tool to study the kinetics and formation mechanism of carbonates.

PubMed

Bonales, L J; Muñoz-Iglesias, V; Santamaría-Pérez, D; Caceres, M; Fernandez-Remolar, D; Prieto-Ballesteros, O

2013-12-01

We have carried out a systematic study of abiotic precipitation at different temperatures of several Mg and Ca carbonates (calcite, nesquehonite, hydrocalcite) present in carbonaceous chondrites. This study highlights the capability of Raman spectroscopy as a primary tool for performing full mineralogical analysis. The precipitation reaction and the structure of the resulting carbonates were monitored and identified with Raman spectroscopy. Raman spectroscopy enabled us to confirm that the precipitation reaction is very fast (minutes) when Ca(II) is present in the solution, whereas for Mg(II) such reactions developed at rather slow rates (weeks). We also observed that both the composition and the reaction mechanisms depended on temperature, which might help to clarify several issues in the fields of planetology and geology, because of the environmental implications of these carbonates on both terrestrial and extraterrestrial objects. Copyright © 2013 Elsevier B.V. All rights reserved.

Ag nanodots decorated SiO2 coated ZnO core-shell nanostructure with enhanced luminescence property as potential imaging agent

NASA Astrophysics Data System (ADS)

Gupta, Jagriti; Barick, K. C.; Hassan, P. A.; Bahadur, Dhirendra

2018-04-01

Ag decorated silica coated ZnO nanocomposite (Ag@SiO2@ZnO NCs) has been synthesized by soft chemical approach. The physico-chemical properties of Ag@SiO2@ZnO NCs are investigated by various sophisticated characterization techniques such as X-ray diffraction, Transmission electron microscopy, X-ray photoelectron spectroscopy, UV-visible absorption and photoluminescent spectroscopy. X-ray diffraction confirms the phase formation of ZnO and Ag in nanocomposite. TEM micrograph clearly shows that Ag nanodots are well decorated over silica coated ZnO NCs. The photoluminescent study reveals the enhancement in the photoluminance property when the Ag nanodots are decorated over silica coated ZnO nanocomposite due to an electromagnetic coupling between excitons and plasmons. Furthermore, the photoluminescent property is an important tool for bio-imaging application, reveal that NCs give green and red emission after excitation with 488 and 535 nm. Therefore, low cytotoxicity and excellent fluorescence stability in vitro makes it a more suitable material for both cellular imaging and therapy for biomedical applications.

Remote Skin Tissue Diagnostics In Vivo By Fiber Optic Evanescent Wave Fourier Transform Infrared (FEW-FTIR) Spectroscopy

NASA Astrophysics Data System (ADS)

Kolyakov, Sergei; Afanasyeva, Natalia; Bruch, Reinhard; Afanasyeva, Natalia

1998-05-01

The new method of fiber optical evanescent wave Fourier transform infrared (FEW-FTIR) spectroscopy has been applied to the diagnostics of normal skin tissue, as well as precancerous and cancerous conditions. The FEW-FTIR technique is nondestructive and sensitive to changes of vibrational spectra in the IR region, without heating and damaging human and animal skin tissue. Therefore this method and technique is an ideal diagnostic tool for tumor and cancer characterization at an early stage of development on a molecular level. The application of fiber optic technology in the middle infrared (MIR) region is relatively inexpensive and can be adapted easily to any commercially available tabletop FTIR spectrometers. This method of diagnostics is fast (several seconds), and can be applied to many fields. Noninvasive medical diagnostics of skin cancer and other skin diseases in vivo, ex vivo, and in vitro allow for the development of convenient, remote clinical applications in dermatology and related fields. The spectral variations from normal to pathological skin tissue and environmental influence on skin have been measured.

Raman and SERS microspectroscopy on living cells: a promising tool toward cellular drug response and medical diagnosis

NASA Astrophysics Data System (ADS)

Beljebbar, Abdelilah; Sockalingum, Ganesh D.; Morjani, Hamid; Manfait, Michel

1999-04-01

Raman spectroscopy has been sued to differentiate between sensitive and MDR-resistant cells using Raman spectral imaging with a 632.8 nm excitation wavelength. The comparison between two spectral images allowed to quantify the differences between sensitive and resistant cell lines in term of proteins, lipids when MDR phenotype is expressed. SER spectroscopy has become a powerful and non-invasive probe for investigating the molecular and cellular interaction of drugs with their targets. The comparison between these models allow to elucidate the biological effect of the drugs. The development of new types of SERS- active substrates has extended the applicability of this technique to medical diagnosis. Two kinds of SERS active substrates, characterized as 'bio-compatible' systems, can be used for investigation on single living cells: colloid suspensions and microelectrodes and island films. This methodology is used for the study of cell membrane components in interaction with the SERS substrates with the aim to understand the resistance mechanism. The constitution of a data bank will allow the follow-up of cancer and future monitoring of therapeutic intervention.

Surface-Enhanced Raman Spectroscopy as a Probe of the Surface Chemistry of Nanostructured Materials.

PubMed

Dick, Susan; Konrad, Magdalena P; Lee, Wendy W Y; McCabe, Hannah; McCracken, John N; Rahman, Taifur M D; Stewart, Alan; Xu, Yikai; Bell, Steven E J

2016-07-01

Surface-enhanced Raman spectroscopy (SERS) is now widely used as a rapid and inexpensive tool for chemical/biochemical analysis. The method can give enormous increases in the intensities of the Raman signals of low-concentration molecular targets if they are adsorbed on suitable enhancing substrates, which are typically composed of nanostructured Ag or Au. However, the features of SERS that allow it to be used as a chemical sensor also mean that it can be used as a powerful probe of the surface chemistry of any nanostructured material that can provide SERS enhancement. This is important because it is the surface chemistry that controls how these materials interact with their local environment and, in real applications, this interaction can be more important than more commonly measured properties such as morphology or plasmonic absorption. Here, the opportunity that this approach to SERS provides is illustrated with examples where the surface chemistry is both characterized and controlled in order to create functional nanomaterials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lipid composition of thermophilic Geobacillus sp. strain GWE1, isolated from sterilization oven.

PubMed

Shah, Siddharth P; Jansen, Susan A; Taylor, Leeandrew Jacques-Asa; Chong, Parkson Lee-Gau; Correa-Llantén, Daniela N; Blamey, Jenny M

2014-05-01

GWE1 strain is an example of anthropogenic thermophilic bacterium, recently isolated from dark crusty material from sterilization ovens by Correa-Llantén et al. (Kor. J. Microb. Biotechnol. 2013. 41(3):278-283). Thermostability is likely to arise from the adaptation of macromolecules such as proteins, lipids and nucleic acids. Complex lipid arrangement and/or type in the cell membrane are known to affect thermostability of microorganisms and efforts were made to understand the chemical nature of the polar lipids of membrane. In this work, we extracted total lipids from GWE1 cell membrane, separated them by TLC into various fractions and characterize the lipid structures of certain fractions with analytical tools such as (1)H, (13)C, (31)P and 2D NMR spectroscopy, ATR-FTIR spectroscopy and MS(n) spectrometry. We were able to identify glycerophosphoethanolamine, glycerophosphate, glycerophosphocholine, glycerophosphoglycerol and cardiolipin lipid classes and an unknown glycerophospholipid class with novel MS/MS spectra pattern. We have also noticed the presence of saturated iso-branched fatty acids with NMR spectra in individual lipid classes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Large array of 2048 tilting micromirrors for astronomical spectroscopy: optical and cryogenic characterization

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Canonica, Michael; Lanzoni, Patrick; Noell, Wilfried; Lani, Sebastien

2014-03-01

Multi-object spectroscopy (MOS) is a powerful tool for space and ground-based telescopes for the study of the formation and evolution of galaxies. This technique requires a programmable slit mask for astronomical object selection. We are engaged in a European development of micromirror arrays (MMA) for generating reflective slit masks in future MOS, called MIRA. MMA with 100 × 200 μm2 single-crystal silicon micromirrors were successfully designed, fabricated and tested. Arrays are composed of 2048 micromirrors (32 x 64) with a peak-to-valley deformation less than 10 nm, a tilt angle of 24° for an actuation voltage of 130 V. The micromirrors were actuated successfully before, during and after cryogenic cooling, down to 162K. The micromirror surface deformation was measured at cryo and is below 30 nm peak-to-valley. These performances demonstrate the ability of such MOEMS device to work as objects selector in future generation of MOS instruments both in ground-based and space telescopes. In order to fill large focal planes (mosaicing of several chips), we are currently developing large micromirror arrays integrated with their electronics.

ESR spectroscopy as a tool for identifying joining fragments of antique marbles: the example of a pulpit by Donatello and Michelozzo.

PubMed

Attanasio, D; Platania, R

2000-06-01

ESR spectroscopy is one of the physicochemical techniques used to characterize archaeological white marbles and obtain information about their quarries of provenance. This is done by measuring selected spectral features of the Mn(2+) impurity ubiquitously present in marbles and developing a statistical classification rule from the variable vectors measured for a significant number of samples of known provenance (the quarry database). Now we show that the overall variability exhibited by the same spectroscopic features decreases rapidly with the linear dimensions of the sampled block and can be used to distinguish fragments belonging to the same piece of stone from those simply originating from the same quarry. Application of the method to the seven marble panels of the Donatello pulpit in Prato (Tuscany) shows that they have all been cut from the same single block and their different degradation must be ascribed to differential weathering and to the different conservation treatments undergone in the past. The limits and possible drawbacks of the method are also discussed. Copyright 2000 Academic Press.

Thermal Gradient Mid- and Far-Infrared Spectroscopy as Tools for Characterization of Protein Carbohydrate Lyophilizates.

PubMed

Mensink, M A; Šibík, J; Frijlink, H W; van der Voort Maarschalk, K; Hinrichs, W L J; Zeitler, J A

2017-10-02

Protein drugs play an important role in modern day medicine. Typically, these proteins are formulated as liquids requiring cold chain processing. To circumvent the cold chain and achieve better storage stability, these proteins can be dried in the presence of carbohydrates. We demonstrate that thermal gradient mid- and far-infrared spectroscopy (FTIR and THz-TDS, respectively) can provide useful information about solid-state protein carbohydrate formulations regarding mobility and intermolecular interactions. A model protein (BSA) was lyophilized in the presence of three carbohydrates with different size and protein stabilizing capacity. A gradual increase in mobility was observed with increasing temperature in formulations containing protein and/or larger carbohydrates (oligo- or polysaccharides), lacking a clear onset of fast mobility as was observed for smaller molecules. Furthermore, both techniques are able to identify the glass transition temperatures (T g ) of the samples. FTIR provides additional information as it can independently monitor changes in protein and carbohydrate bands at the T g . Lastly, THz-TDS confirms previous findings that protein-carbohydrate interactions decrease with increasing molecular weight of the carbohydrate, which results in decreased protein stabilization.

Post-Kerr black hole spectroscopy

NASA Astrophysics Data System (ADS)

Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele

2017-09-01

One of the central goals of the newborn field of gravitational wave astronomy is to test gravity in the highly nonlinear, strong field regime characterizing the spacetime of black holes. In particular, "black hole spectroscopy" (the observation and identification of black hole quasinormal mode frequencies in the gravitational wave signal) is expected to become one of the main tools for probing the structure and dynamics of Kerr black holes. In this paper we take a significant step toward that goal by constructing a "post-Kerr" quasinormal mode formalism. The formalism incorporates a parametrized but general perturbative deviation from the Kerr metric and exploits the well-established connection between the properties of the spacetime's circular null geodesics and the fundamental quasinormal mode to provide approximate, eikonal limit formulas for the modes' complex frequencies. The resulting algebraic toolkit can be used in waveform templates for ringing black holes with the purpose of measuring deviations from the Kerr metric. As a first illustrative application of our framework, we consider the Johannsen-Psaltis deformed Kerr metric and compute the resulting deviation in the quasinormal mode frequency relative to the known Kerr result.

Analytical study of Saint Gregory Nazianzen Icon, Old Cairo, Egypt

NASA Astrophysics Data System (ADS)

Issa, Yousry M.; Abdel-Maksoud, Gomaa; Magdy, Mina

2015-11-01

The study aims to evaluate the state of icon through characterization of the icon layers (ground, paint and varnish layers) and to provide tools for assessment the impact of aging and environmental conditions in order to produce some solutions for conservation of the icon. Analytical techniques used in this study were attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscope-energy dispersive X ray spectroscopy (FESEM-EDX) and amino acid analyzer (AAA). The results obtained revealed that gypsum and lead white were used for ground layer. The identified pigments were lamp carbon black, brown ochre, Prussian blue, yellow ochre and gold leaf. Egg yolk was the binder used with most of pigments and animal glue was used with gold color. The varnish used was shellac resin. It was concluded that stable pigments gave permanent colors and environmental conditions had an influence on promotion of oxidation process. Auto-oxidation of binder and varnish materials occurred by the action of pigment components and light result in cracking of the paint film and fading of the varnish glaze.

Cd hyperfine interactions in DNA bases and DNA of mouse strains infected with Trypanosoma cruzi investigated by perturbed angular correlation spectroscopy and ab initio calculations.

PubMed

Petersen, Philippe A D; Silva, Andreia S; Gonçalves, Marcos B; Lapolli, André L; Ferreira, Ana Maria C; Carbonari, Artur W; Petrilli, Helena M

2014-06-03

In this work, perturbed angular correlation (PAC) spectroscopy is used to study differences in the nuclear quadrupole interactions of Cd probes in DNA molecules of mice infected with the Y-strain of Trypanosoma cruzi. The possibility of investigating the local genetic alterations in DNA, which occur along generations of mice infected with T. cruzi, using hyperfine interactions obtained from PAC measurements and density functional theory (DFT) calculations in DNA bases is discussed. A comparison of DFT calculations with PAC measurements could determine the type of Cd coordination in the studied molecules. To the best of our knowledge, this is the first attempt to use DFT calculations and PAC measurements to investigate the local environment of Cd ions bound to DNA bases in mice infected with Chagas disease. The obtained results also allowed the detection of local changes occurring in the DNA molecules of different generations of mice infected with T. cruzi, opening the possibility of using this technique as a complementary tool in the characterization of complicated biological systems.

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Petronijevic, E.; Leahu, G.; Belardini, A.; Centini, M.; Li Voti, R.; Hakkarainen, T.; Koivusalo, E.; Guina, M.; Sibilia, C.

2018-03-01

Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application.

The use of UV-visible reflectance spectroscopy as an objective tool to evaluate pearl quality.

PubMed

Agatonovic-Kustrin, Snezana; Morton, David W

2012-07-01

Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl's quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry.

Nondestructive surface analysis for material research using fiber optic vibrational spectroscopy

NASA Astrophysics Data System (ADS)

Afanasyeva, Natalia I.

2001-11-01

The advanced methods of fiber optical vibrational spectroscopy (FOVS) has been developed in conjunction with interferometer and low-loss, flexible, and nontoxic optical fibers, sensors, and probes. The combination of optical fibers and sensors with Fourier Transform (FT) spectrometer has been used in the range from 2.5 to 12micrometers . This technique serves as an ideal diagnostic tool for surface analysis of numerous and various diverse materials such as complex structured materials, fluids, coatings, implants, living cells, plants, and tissue. Such surfaces as well as living tissue or plants are very difficult to investigate in vivo by traditional FT infrared or Raman spectroscopy methods. The FOVS technique is nondestructive, noninvasive, fast (15 sec) and capable of operating in remote sampling regime (up to a fiber length of 3m). Fourier transform infrared (FTIR) and Raman fiber optic spectroscopy operating with optical fibers has been suggested as a new powerful tool. These techniques are highly sensitive techniques for structural studies in material research and various applications during process analysis to determine molecular composition, chemical bonds, and molecular conformations. These techniques could be developed as a new tool for quality control of numerous materials as well as noninvasive biopsy.

Synthesis and Characterization of YVO4-Based Phosphor Doped with Eu3+ Ions for Display Devices

NASA Astrophysics Data System (ADS)

Thakur, Shashi; Gathania, Arvind K.

2015-10-01

YVO4:Eu nanophosphor has been synthesized by the sol-gel method. Samples were characterized by x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence, and Raman spectroscopy. The XRD profile confirms the tetragonal phase of the Eu3+-doped YVO4 nanophosphor. The efficiency of the prepared phosphor was analyzed by means of its emission spectral profile. We also observed rich red emission from the prepared phosphor on excitation by an ultraviolet source. The calculated Commission International de l'Éclairage coordinates reveal excellent color purity efficiency. Such luminescent powder is useful as red phosphor in display device applications.

Stepwise synthesis and characterization of germa[4], [5], [8], and [10]pericyclynes.

PubMed

Tanimoto, Hiroki; Nagao, Tomohiko; Fujiwara, Taro; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Suzuka, Toshimasa; Tsutsumi, Ken; Kakiuchi, Kiyomi

2015-07-14

The stepwise syntheses of germa[N]pericyclynes, including [5]pericyclynes, and their characterization are described. The yields of germa[4] and [8]pericyclynes were improved significantly compared to those obtained in previous studies. The routes reported herein afforded the novel germa[5] and [10]pericyclynes, which were characterized by X-ray crystallography, UV-Vis spectroscopy, and fluorescence emission spectroscopy. A unique fluorescence emission was observed for the large germa[10]pericyclyne ring.

INFRARED SPECTROSCOPY: A TOOL FOR DETERMINATION OF THE DEGREE OF CONVERSION IN DENTAL COMPOSITES

PubMed Central

Moraes, Luciene Gonçalves Palmeira; Rocha, Renata Sanches Ferreira; Menegazzo, Lívia Maluf; de AraÚjo, Eudes Borges; Yukimitu, Keizo; Moraes, João Carlos Silos

2008-01-01

Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree. PMID:19089207

Characterization of weakly ionized argon flows for radio blackout mitigation experiments

NASA Astrophysics Data System (ADS)

Steffens, L.; Koch, U.; Esser, B.; Gülhan, A.

2017-06-01

For reproducing the so-called E × B communication blackout mitigation scheme inside the L2K arc heated facility of the DLR in weakly ionized argon §ows, a §at plate model has been equipped with a superconducting magnet, electrodes, and a setup comprising microwave plasma transmission spectroscopy (MPTS). A thorough characterization of the weakly ionized argon §ow has been performed including the use of microwave interferometry (MWI), Langmuir probe measurements, Pitot probe pro¦les, and spectroscopic methods like diode laser absorption spectroscopy (DLAS) and emission spectroscopy.

Suicide Inhibitors of Reverse Transcriptase in the Therapy of AIDS and Other Retroviruses

DTIC Science & Technology

1991-07-01

procedures and characterized by IR and NMR spectroscopy . 140 OH py’ridine Ho t O0Tr OHr01 9 10 1 croi 0 0 Aco uO (CH43)2 -CN TOOH pyridja. 0 OxTr D?450...NMR spectroscopy . The observed chemical shifts are comparable to those reported ’in the literature. The spectrum is of the ABX type where the AB part...characterized by NMR spectroscopy . The presence of the characteristic triphosphate group was confirmed by NMR as indicated in the figure below. NMR

Toward the development of Raman spectroscopy as a nonperturbative online monitoring tool for gasoline adulteration.

PubMed

Tan, Khay M; Barman, Ishan; Dingari, Narahara C; Singh, Gajendra P; Chia, Tet F; Tok, Wee L

2013-02-05

There is a critical need for a real-time, nonperturbative probe for monitoring the adulteration of automotive gasoline. Running on adulterated fuel leads to a substantive increase in air pollution, because of increased tailpipe emissions of harmful pollutants, as well as a reduction in engine performance. Consequently, both classification of the gasoline type and quantification of the adulteration content are of great significance for quality control. Gasoline adulteration detection is currently carried out in the laboratory with gas chromatography, which is time-consuming and costly. Here, we propose the application of Raman spectroscopic measurements for on-site rapid detection of gasoline adulteration. In this proof-of-principle report, we demonstrate the effectiveness of Raman spectra, in conjunction with multivariate analysis methods, in classifying the base oil types and simultaneously detecting the adulteration content in a wide range of commercial gasoline mixtures, both in their native states and spiked with different adulterants. In particular, we show that Raman spectra acquired with an inexpensive noncooled detector provides adequate specificity to clearly discriminate between the gasoline samples and simultaneously characterize the specific adulterant content with a limit of detection below 5%. Our promising results in this study illustrate, for the first time, the capability and the potential of Raman spectroscopy, together with multivariate analysis, as a low-cost, powerful tool for on-site rapid detection of gasoline adulteration and opens substantive avenues for applications in related fields of quality control in the oil industry.

Quantum dot nanoparticle conjugation, characterization, and applications in neuroscience

NASA Astrophysics Data System (ADS)

Pathak, Smita

Quantum dot are semiconducting nanoparticles that have been used for decades in a variety of applications such as solar cells, LEDs and medical imaging. Their use in the last area, however, has been extremely limited despite their potential as revolutionary new biological labeling tools. Quantum dots are much brighter and more stable than conventional fluorophores, making them optimal for high resolution imaging and long term studies. Prior work in this area involves synthesizing and chemically conjugating quantum dots to molecules of interest in-house. However this method is both time consuming and prone to human error. Additionally, non-specific binding and nanoparticle aggregation currently prevent researchers from utilizing this system to its fullest capacity. Another critical issue that has not been addressed is determining the number of ligands bound to nanoparticles, which is crucial for proper interpretation of results. In this work, methods to label fixed cells using two types of chemically modified quantum dots are studied. Reproducible non-specific artifact labeling is consistently demonstrated if antibody-quantum dot conditions are less than optimal. In order to explain this, antibodies bound to quantum dots were characterized and quantified. While other groups have qualitatively characterized antibody functionalized quantum dots using TEM, AFM, UV spectroscopy and gel electrophoresis, and in some cases have reported calculated estimates of the putative number of total antibodies bound to quantum dots, no quantitative experimental results had been reported prior to this work. The chemical functionalization and characterization of quantum dot nanocrystals achieved in this work elucidates binding mechanisms of ligands to nanoparticles and allows researchers to not only translate our tools to studies in their own areas of interest but also derive quantitative results from these studies. This research brings ease of use and increased reliability to nanoparticles in medical imaging.

GEAS Spectroscopy Tools for Authentic Research Investigations in the Classroom

NASA Astrophysics Data System (ADS)

Rector, Travis A.; Vogt, Nicole P.

2018-06-01

Spectroscopy is one of the most powerful tools that astronomers use to study the universe. However relatively few resources are available that enable undergraduates to explore astronomical spectra interactively. We present web-based applications which guide students through the analysis of real spectra of stars, galaxies, and quasars. The tools are written in HTML5 and function in all modern web browsers on computers and tablets. No software needs to be installed nor do any datasets need to be downloaded, enabling students to use the tools in or outside of class (e.g., for online classes).Approachable GUIs allow students to analyze spectra in the same manner as professional astronomers. The stellar spectroscopy tool can fit a continuum with a blackbody and identify spectral features, as well as fit line profiles and determine equivalent widths. The galaxy and AGN tools can also measure redshifts and calcium break strengths. The tools provide access to an archive of hundreds of spectra obtained with the optical telescopes at Kitt Peak National Observatory. It is also possible to load your own spectra or to query the Sloan Digital Sky Survey (SDSS) database.We have also developed curricula to investigate these topics: spectral classification, variable stars, redshift, and AGN classification. We will present the functionality of the tools and describe the associated curriculum. The tools are part of the General Education Astronomy Source (GEAS) project based at New Mexico State University, with support from the National Science Foundation (NSF, AST-0349155) and the National Aeronautics and Space Administration (NASA, NNX09AV36G). Curriculum development was supported by the NSF (DUE-0618849 and DUE-0920293).

Deriving stellar parameters with the SME software package

NASA Astrophysics Data System (ADS)

Piskunov, N.

2017-09-01

Photometry and spectroscopy are complementary tools for deriving accurate stellar parameters. Here I present one of the popular packages for stellar spectroscopy called SME with the emphasis on the latest developments and error assessment for the derived parameters.

Time- and Space-Resolved Spectroscopic Investigation on Pi-Conjugated Nanostructures - 2

DTIC Science & Technology

2016-01-12

15. SUBJECT TERMS Materials Characterization, Materials Chemistry, Nonlinear Optical Materials, Spectroscopy 16. SECURITY CLASSIFICATION...nanostructures will translate into new ground-breaking developments that not only allow the structure-property relationships to be probed in greater detail... spectroscopy . I. Experimental method 1. Steady-state Spectroscopy - UV-Vis-NIR Absorption & Emission Steady-state Spectroscopy - NIR

A highly ordered mesostructured material containing regularly distributed phenols: preparation and characterization at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy.

PubMed

Roussey, Arthur; Gajan, David; Maishal, Tarun K; Mukerjee, Anhurada; Veyre, Laurent; Lesage, Anne; Emsley, Lyndon; Copéret, Christophe; Thieuleux, Chloé

2011-03-14

Highly ordered organic-inorganic mesostructured material containing regularly distributed phenols is synthesized by combining a direct synthesis of the functional material and a protection-deprotection strategy and characterized at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy.

Synthesis and characterization of a new photoluminescent material, tris-[1-10 phenanthroline] aluminium

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

Kumar, Rahul, E-mail: id-kumarrahul003@gmail.com; Bhargava, Parag; Dvivedi, Avanish

A new photoluminescent material namely tris-[1-10 Phenanthroline] Aluminium Al(Phen){sub 3} has been synthesized and characterized. This material was characterized by fourier transform infrared spectroscopy (FTIR),nuclear magnetic resonance (NMR),mass spectroscopy, thermal gravimetric analysis (TGA),ultraviolet-visible spectroscopy(UV) and photoluminescence (PL). This material shows thermal stability up to 300°C. This material showed absorption maxima at 352nm which may be attributed to the moderate energy (π–π{sup *}) transition. Photoluminescence spectra for this material showed the most intense peak at 423 nm and the time resolved photoluminescence spectra showed two life time components. The decay times of the first and second component were 1.4ns and 4.8 ns respectively.

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.

Materials characterization of free volume and void properties by two-dimensional positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Hongmin; Van Horn, J. David; Jean, Y. C.; Hung, Wei-Song; Lee, Kueir-Rarn

2013-04-01

Positron annihilation lifetime spectroscopy (PALS) has been widely used to determine the free volume and void properties in polymeric materials. Recently, a two dimensional positron annihilation lifetime spectroscopy (2DPALS) system has been developed for membrane applications. The system measures the coincident signals between the lifetime and the energy which could separate the 2γ and 3γ annihilations and improve the accuracy in the determination of the free volume and void properties. When 2D-PALS is used in coupling with a variable mono-energy slow positron beam, it could be applied to a variety of material characterization. Results of free volumes and voids properties in a multi-layer polymer membrane characterized using 2D-PALS are presented.

Emerging applications of fluorescence spectroscopy in medical microbiology field.

PubMed

Shahzad, Aamir; Köhler, Gottfried; Knapp, Martin; Gaubitzer, Erwin; Puchinger, Martin; Edetsberger, Michael

2009-11-26

There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

The impact of detergents on the tissue decellularization process: A ToF-SIMS study.

PubMed

White, Lisa J; Taylor, Adam J; Faulk, Denver M; Keane, Timothy J; Saldin, Lindsey T; Reing, Janet E; Swinehart, Ilea T; Turner, Neill J; Ratner, Buddy D; Badylak, Stephen F

2017-03-01

Biologic scaffolds are derived from mammalian tissues, which must be decellularized to remove cellular antigens that would otherwise incite an adverse immune response. Although widely used clinically, the optimum balance between cell removal and the disruption of matrix architecture and surface ligand landscape remains a considerable challenge. Here we describe the use of time of flight secondary ion mass spectroscopy (ToF-SIMS) to provide sensitive, molecular specific, localized analysis of detergent decellularized biologic scaffolds. We detected residual detergent fragments, specifically from Triton X-100, sodium deoxycholate and sodium dodecyl sulphate (SDS) in decellularized scaffolds; increased SDS concentrations from 0.1% to 1.0% increased both the intensity of SDS fragments and adverse cell outcomes. We also identified cellular remnants, by detecting phosphate and phosphocholine ions in PAA and CHAPS decellularized scaffolds. The present study demonstrates ToF-SIMS is not only a powerful tool for characterization of biologic scaffold surface molecular functionality, but also enables sensitive assessment of decellularization efficacy. We report here on the use of a highly sensitive analytical technique, time of flight secondary ion mass spectroscopy (ToF-SIMS) to characterize detergent decellularized scaffolds. ToF-SIMS detected cellular remnants and residual detergent fragments; increased intensity of the detergent fragments correlated with adverse cell matrix interactions. This study demonstrates the importance of maintaining a balance between cell removal and detergent disruption of matrix architecture and matrix surface ligand landscape. This study also demonstrates the power of ToF-SIMS for the characterization of decellularized scaffolds and capability for assessment of decellularization efficacy. Future use of biologic scaffolds in clinical tissue reconstruction will benefit from the fundamental results described in this work. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Analysis of calibration materials to improve dual-energy CT scanning for petrophysical applications

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

Ayyalasomavaiula, K.; McIntyre, D.; Jain, J.

2011-01-01

Dual energy CT-scanning is a rapidly emerging imaging technique employed in non-destructive evaluation of various materials. Although CT (Computerized Tomography) has been used for characterizing rocks and visualizing and quantifying multiphase flow through rocks for over 25 years, most of the scanning is done at a voltage setting above 100 kV for taking advantage of the Compton scattering (CS) effect, which responds to density changes. Below 100 kV the photoelectric effect (PE) is dominant which responds to the effective atomic numbers (Zeff), which is directly related to the photo electric factor. Using the combination of the two effects helps inmore » better characterization of reservoir rocks. The most common technique for dual energy CT-scanning relies on homogeneous calibration standards to produce the most accurate decoupled data. However, the use of calibration standards with impurities increases the probability of error in the reconstructed data and results in poor rock characterization. This work combines ICP-OES (inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectroscopy) analytical techniques to quantify the type and level of impurities in a set of commercially purchased calibration standards used in dual-energy scanning. The Zeff data on the calibration standards with and without impurity data were calculated using the weighted linear combination of the various elements present and used in calculating Zeff using the dual energy technique. Results show 2 to 5% difference in predicted Zeff values which may affect the corresponding log calibrations. The effect that these techniques have on improving material identification data is discussed and analyzed. The workflow developed in this paper will translate to a more accurate material identification estimates for unknown samples and improve calibration of well logging tools.« less

Effect of acidic aqueous solution on chemical and physical properties of polyamide NF membranes

NASA Astrophysics Data System (ADS)

Jun, Byung-Moon; Kim, Su Hwan; Kwak, Sang Kyu; Kwon, Young-Nam

2018-06-01

This work was systematically investigated the effects of acidic aqueous solution (15 wt% sulfuric acid as model wastewater from smelting process) on the physical and chemical properties of commercially available nanofiltration (NF) polyamide membranes, using piperazine (PIP)-based NE40/70 membranes and m-phenylene diamine (MPD)-based NE90 membrane. Surface properties of the membranes were studied before and after exposure to strong acid using various analytical tools: Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), contact angle analyzer, and electrophoretic light scattering spectrophotometer. The characterization and permeation results showed piperazine-based NE40/70 membranes have relatively lower acid-resistance than MPD-based NE90 membrane. Furthermore, density functional theory (DFT) calculation was also conducted to reveal the different acid-tolerances between the piperazine-based and MPD-based polyamide membranes. The easiest protonation was found to be the protonation of oxygen in piperazine-based monomer, and the N-protonation of the monomer had the lowest energy barrier in the rate determining step (RDS). The calculations were well compatible with the surface characterization results. In addition, the energy barrier in RDS is highly correlated with the twist angle (τD), which determines the delocalization of electrons between the carbonyl πCO bond and nitrogen lone pair, and the tendency of the twist angle was also maintained in longer molecules (dimer and trimer). This study clearly explained why the semi-aromatic membrane (NE40/70) is chemically less stable than the aromatic membrane (NE90) given the surface characterizations and DFT calculation results.

Methodology for cork plank characterization (Quercus suber L.) by near-infrared spectroscopy and image analysis

NASA Astrophysics Data System (ADS)

Prades, Cristina; García-Olmo, Juan; Romero-Prieto, Tomás; García de Ceca, José L.; López-Luque, Rafael

2010-06-01

The procedures used today to characterize cork plank for the manufacture of cork bottle stoppers continue to be based on a traditional, manual method that is highly subjective. Furthermore, there is no specific legislation regarding cork classification. The objective of this viability study is to assess the potential of near-infrared spectroscopy (NIRS) technology for characterizing cork plank according to the following variables: aspect or visual quality, porosity, moisture and geographical origin. In order to calculate the porosity coefficient, an image analysis program was specifically developed in Visual Basic language for a desktop scanner. A set comprising 170 samples from two geographical areas of Andalusia (Spain) was classified into eight quality classes by visual inspection. Spectra were obtained in the transverse and tangential sections of the cork planks using an NIRSystems 6500 SY II reflectance spectrophotometer. The quantitative calibrations showed cross-validation coefficients of determination of 0.47 for visual quality, 0.69 for porosity and 0.66 for moisture. The results obtained using NIRS technology are promising considering the heterogeneity and variability of a natural product such as cork in spite of the fact that the standard error of cross validation (SECV) in the quantitative analysis is greater than the standard error of laboratory (SEL) for the three variables. The qualitative analysis regarding geographical origin achieved very satisfactory results. Applying these methods in industry will permit quality control procedures to be automated, as well as establishing correlations between the different classification systems currently used in the sector. These methods can be implemented in the cork chain of custody certification and will also provide a certainly more objective tool for assessing the economic value of the product.

Fourier transform-infrared spectroscopy as a diagnostic tool for mosquito coil smoke inhalation toxicity in Swiss Albino mice

NASA Astrophysics Data System (ADS)

Anusha, Chidambaram; Sankar, Renu; Varunkumar, Krishnamoorthy; Sivasindhuja, Gnanasambantham; Ravikumar, Vilwanathan

2017-12-01

The goal of this study is to establish Fourier transform-infrared (FTIR) spectroscopy as a diagnostic tool for allethrin-based mosquito coil smoke inhalation induced toxicity in mice. Primarily, we confirmed mosquito coil smoke inhalation toxicity in mice via reduced the body, organ weight and major vital organ tissue morphological structure changes. Furthermore, FTIR spectra was collected from control and mosquito coil smoke inhalation (8 h per day for 30 days) mice various tissues like liver, kidney, lung, heart and brain, to investigate the functional groups and their corresponding biochemical content variations. The FTIR spectra result shown major bio macromolecules such as protein and lipid functional peaks were shifted (decreased) in the mosquito coil smoke inhalation group as compared to control. The drastic peak shift was noticed in the liver, kidney followed by lung and brain. It is therefore concluded that the FTIR spectroscopy can be a successful detection tool in mosquito coil smoke inhalation toxicity.

Direct Observation of Markovian Behavior of the Mechanical Unfolding of Individual Proteins

PubMed Central

Cao, Yi; Kuske, Rachel; Li, Hongbin

2008-01-01

Single-molecule force-clamp spectroscopy is a valuable tool to analyze unfolding kinetics of proteins. Previous force-clamp spectroscopy experiments have demonstrated that the mechanical unfolding of ubiquitin deviates from the generally assumed Markovian behavior and involves the features of glassy dynamics. Here we use single molecule force-clamp spectroscopy to study the unfolding kinetics of a computationally designed fast-folding mutant of the small protein GB1, which shares a similar β-grasp fold as ubiquitin. By treating the mechanical unfolding of polyproteins as the superposition of multiple identical Poisson processes, we developed a simple stochastic analysis approach to analyze the dwell time distribution of individual unfolding events in polyprotein unfolding trajectories. Our results unambiguously demonstrate that the mechanical unfolding of NuG2 fulfills all criteria of a memoryless Markovian process. This result, in contrast with the complex mechanical unfolding behaviors observed for ubiquitin, serves as a direct experimental demonstration of the Markovian behavior for the mechanical unfolding of a protein and reveals the complexity of the unfolding dynamics among structurally similar proteins. Furthermore, we extended our method into a robust and efficient pseudo-dwell-time analysis method, which allows one to make full use of all the unfolding events obtained in force-clamp experiments without categorizing the unfolding events. This method enabled us to measure the key parameters characterizing the mechanical unfolding energy landscape of NuG2 with improved precision. We anticipate that the methods demonstrated here will find broad applications in single-molecule force-clamp spectroscopy studies for a wide range of proteins. PMID:18375518

New insight into protein-nanomaterial interactions with UV-visible spectroscopy and chemometrics: human serum albumin and silver nanoparticles.

PubMed

Wang, Yong; Ni, Yongnian

2014-01-21

In recent years, great efforts have focused on the exploration and fabrication of protein nanoconjugates due to potential applications in many fields including bioanalytical science, biosensors, biocatalysis, biofuel cells and bio-based nanodevices. An important aspect of our understanding of protein nanoconjugates is to quantitatively understand how proteins interact with nanomaterials. In this report, human serum albumin (HSA) and citrate-coated silver nanoparticles (AgNPs) are selected as a case study of protein-nanomaterial interactions. UV-visible spectroscopy together with multivariate curve resolution by alternating least squares (MCR-ALS) algorithm is first exploited for the detailed study of AgNPs-HSA interactions. Introduction of the chemometrics tool allows extracting the kinetic profiles, spectra and distribution diagrams of two major absorbing pure species (AgNPs and AgNPs-HSA conjugate). These resolved profiles are then analysed to give the thermodynamic, kinetic and structural information of HSA binding to AgNPs. Transmission electron microscopy, circular dichroism spectroscopy and Fourier transform infrared spectroscopy are used to further characterize the complex system. Moreover, a sensitive spectroscopic biosensor for HSA is fabricated with the MCR-ALS resolved concentration of absorbing pure species. It is found that the linear range for the HSA nanosensor was from 1.9 nM to 45.0 nM with a detection limit of 0.9 nM. It is believed that the proposed method will play an important role in the fabrication and optimization of a robust nanobiosensor or cross-reactive sensors array for the detection and identification of biocomponents.

Staging research of human lung cancer tissues by high-resolution magic angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS 1 H NMR) and multivariate data analysis.

PubMed

Chen, Wenxue; Lu, Shaohua; Wang, Guifang; Chen, Fener; Bai, Chunxue

2017-10-01

High-resolution magic-angle spinning proton nuclear magnetic resonance (HRMAS 1 H NMR) spectroscopy technique was employed to analyze the metabonomic characterizations of lung cancer tissues in hope to identify potential diagnostic biomarkers for malignancy detection and staging research of lung tissues. HRMAS 1 H NMR spectroscopy technique can rapidly provide important information for accurate diagnosis and staging of cancer tissues owing to its noninvasive nature and limited requirement for the samples, and thus has been acknowledged as an excellent tool to investigate tissue metabolism and provide a more realistic insight into the metabonomics of tissues when combined with multivariate data analysis (MVDA) such as component analysis and orthogonal partial least squares-discriminant analysis in particular. HRMAS 1 H NMR spectra displayed the metabonomic differences of 32 lung cancer tissues at the different stages from 32 patients. The significant changes (P < 0.05) of some important metabolites such as lipids, aspartate and choline-containing compounds in cancer tissues at the different stages had been identified. Furthermore, the combination of HRMAS 1 H NMR spectroscopy and MVDA might potentially and precisely provided for a high sensitivity, specificity, prediction accuracy in the positive identification of the staging for the cancer tissues in contrast with the pathological data in clinic. This study highlighted the potential of metabonomics in clinical settings so that the techniques might be further exploited for the diagnosis and staging prediction of lung cancer in future. © 2016 John Wiley & Sons Australia, Ltd.

Two-Dimensional Spectroscopy Is Being Used to Address Core Scientific Questions in Biology and Materials Science.

PubMed

Petti, Megan K; Lomont, Justin P; Maj, Michał; Zanni, Martin T

2018-02-15

Two-dimensional spectroscopy is a powerful tool for extracting structural and dynamic information from a wide range of chemical systems. We provide a brief overview of the ways in which two-dimensional visible and infrared spectroscopies are being applied to elucidate fundamental details of important processes in biological and materials science. The topics covered include amyloid proteins, photosynthetic complexes, ion channels, photovoltaics, batteries, as well as a variety of promising new methods in two-dimensional spectroscopy.

XPS study of ruthenium tris-bipyridine electrografted from diazonium salt derivative on microcrystalline boron doped diamond.

PubMed

Agnès, Charles; Arnault, Jean-Charles; Omnès, Franck; Jousselme, Bruno; Billon, Martial; Bidan, Gérard; Mailley, Pascal

2009-12-28

Boron doped diamond (BDD) functionalization has received an increasing interest during the last few years. Such an infatuation comes from the original properties of BDD, including chemical stability or an electrochemical window, that opens the way for the design of (bio)sensors or smart interfaces. In such a context, diazonium salts appear to be well suited for BDD functionalization as they enable covalent immobilization of functional entities such as enzymes or DNA. In this study we report microcrystalline BDD functionalization with a metallic complex, ruthenium tris(bipyridine), using the p-(tris(bipyridine)Ru(2+))phenyl diazonium salt. Electrografting using cyclic voltammetry (CV) allowed the formation of a ruthenium complex film that was finely characterized using electrochemistry and X-ray photoelectron spectroscopy (XPS). Moreover, we showed that chronopotentiometry (CP) is a convenient tool to monitor Ru complex film deposition through the control of the electrochemical pulse parameters (i.e. current density and pulse duration). Finally, such a control was demonstrated through the correlation between electrochemical and XPS characterizations.

Direct observation of conductive filament formation in Alq3 based organic resistive memories

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

Busby, Y., E-mail: yan.busby@unamur.be; Pireaux, J.-J.; Nau, S.

2015-08-21

This work explores resistive switching mechanisms in non-volatile organic memory devices based on tris(8-hydroxyquinolie)aluminum (Alq{sub 3}). Advanced characterization tools are applied to investigate metal diffusion in ITO/Alq{sub 3}/Ag memory device stacks leading to conductive filament formation. The morphology of Alq{sub 3}/Ag layers as a function of the metal evaporation conditions is studied by X-ray reflectivity, while depth profile analysis with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry is applied to characterize operational memory elements displaying reliable bistable current-voltage characteristics. 3D images of the distribution of silver inside the organic layer clearly point towards the existence of conductive filamentsmore » and allow for the identification of the initial filament formation and inactivation mechanisms during switching of the device. Initial filament formation is suggested to be driven by field assisted diffusion of silver from abundant structures formed during the top electrode evaporation, whereas thermochemical effects lead to local filament inactivation.« less

Flame extinction limit and particulates formation in fuel blends

NASA Astrophysics Data System (ADS)

Subramanya, Mahesh

Many fuels used in material processing and power generation applications are generally a blend of various hydrocarbons. Although the combustion and aerosol formation dynamics of individual fuels is well understood, the flame dynamics of fuel blends are yet to be characterized. This research uses a twin flame counterflow burner to measure flame velocity, flame extinction, particulate formation and particulate morphology of hydrogen fuel blend flames at different H2 concentration, oscillation frequencies and stretch conditions. Phase resolved spectroscopic measurements (emission spectra) of OH, H, O and CH radical/atom concentrations is used to characterize the heat release processes of the flame. In addition flame generated particulates are collected using thermophoretic sample technique and are qualitative analyzed using Raman Spectroscopy and SEM. Such measurements are essential for the development of advanced computational tools capable of predicting fuel blend flame characteristics at realistic combustor conditions. The data generated through the measurements of this research are representative, and yet accurate, with unique well defined boundary conditions which can be reproduced in numerical computations for kinetic code validations.

Nitrogen: A New Class of π-Bonding Partner in Hetero π-Stacking Interaction.

PubMed

Ramanathan, N; Sankaran, K; Sundararajan, K

2017-11-30

Spectroscopy under isolated conditions at low temperatures is an excellent tool to characterize the aggregates stabilized through weak interactions. Within the framework of weak interactions, the π-stacking interactions are considered unconventional with the limited experimental proofs, wherein the bonding associates are either aromatic and heterocyclic compounds or their combinations. Besides aromatic compounds, π-stacking networks can even be realized with molecules possessing electron rich π-clouds. In this work, the N 2 molecule as a possible π-bonding partner is explored for the first time in which hetero π-stacking was achieved between pyrrole and N 2 precursors. The matrix isolation experiments performed by seeding pyrrole and N 2 mixtures in an Ar matrix at low temperatures with subsequent infrared spectral characterization revealed the generation of adducts stabilized through a π(pyrrole)···π(N 2 ) interaction. Under identical conditions with the likelihood of two competing π-stacking and hydrogen-bonding interactions in pyrrole-N 2 associates, π-stacking dominates energetically over hydrogen-bonding interaction.

DFT-Assisted Polymorph Identification from Lattice Raman Fingerprinting

PubMed Central

2017-01-01

A combined experimental and theoretical approach, consisting of lattice phonon Raman spectroscopy and density functional theory (DFT) calculations, is proposed as a tool for lattice dynamics characterization and polymorph phase identification. To illustrate the reliability of the method, the lattice phonon Raman spectra of two polymorphs of the molecule 2,7-dioctyloxy[1]benzothieno[3,2-b]benzothiophene are investigated. We show that DFT calculations of the lattice vibrations based on the known crystal structures, including many-body dispersion van der Waals (MBD-vdW) corrections, predict experimental data within an accuracy of ≪5 cm–1 (≪0.6 meV). Due to the high accuracy of the simulations, they can be used to unambiguously identify different polymorphs and to characterize the nature of the lattice vibrations and their relationship to the structural properties. More generally, this work implies that DFT-MBD-vdW is a promising method to describe also other physical properties that depend on lattice dynamics like charge transport. PMID:28731723

Revealing the planar chemistry of two-dimensional heterostructures at the atomic level.

PubMed

Chou, Harry; Ismach, Ariel; Ghosh, Rudresh; Ruoff, Rodney S; Dolocan, Andrei

2015-06-23

Two-dimensional (2D) atomic crystals and their heterostructures are an intense area of study owing to their unique properties that result from structural planar confinement. Intrinsically, the performance of a planar vertical device is linked to the quality of its 2D components and their interfaces, therefore requiring characterization tools that can reveal both its planar chemistry and morphology. Here, we propose a characterization methodology combining (micro-) Raman spectroscopy, atomic force microscopy and time-of-flight secondary ion mass spectrometry to provide structural information, morphology and planar chemical composition at virtually the atomic level, aimed specifically at studying 2D vertical heterostructures. As an example system, a graphene-on-h-BN heterostructure is analysed to reveal, with an unprecedented level of detail, the subtle chemistry and interactions within its layer structure that can be assigned to specific fabrication steps. Such detailed chemical information is of crucial importance for the complete integration of 2D heterostructures into functional devices.

Delafossite structure of heterogenite polytypes (HCoO2) by Raman and infrared micro-spectroscopy

NASA Astrophysics Data System (ADS)

Burlet, C.; Goethals, H.; Vanbrabant, Y.

2016-04-01

Heterogenite is commonly referred in mineralogy literature as a cobalt oxy-hydroxide CoO(OH). However, detailed analysis of Raman and infrared spectra acquired on particularly well-crystallized natural samples of heterogenite suggests that the mineral can be characterized by a delafossite-type structure, with a general chemical formula ABO2. Indeed, the Raman spectrum of heterogenite, along the one with grimaldiite (HCrO2), lacks visible free OH-group vibrational modes, while the infrared spectrum shows strong hydrogen bond absorption bands. HCoO2 is thus a better formulation of heterogenite that describes more clearly its vibrational behavior and avoids the confusion in literature. Electronic backscattered diffraction (EBSD) is then used to distinguish and map the 2H and 3R heterogenite natural polytypes for the first time. The comparison of EBSD and Raman mappings clearly indicates that the 2H polytype is characterized by an additional peak at 1220 cm- 1. The presence/absence is therefore an efficient tool to distinguish both polytypes.

Characterization of an array of honeys of different types and botanical origins through fluorescence emission based on LEDs.

PubMed

Lastra-Mejías, Miguel; Torreblanca-Zanca, Albertina; Aroca-Santos, Regina; Cancilla, John C; Izquierdo, Jesús G; Torrecilla, José S

2018-08-01

A set of 10 honeys comprising a diverse range of botanical origins have been successfully characterized through fluorescence spectroscopy using inexpensive light-emitting diodes (LEDs) as light sources. It has been proven that each LED-honey combination tested originates a unique emission spectrum, which enables the authentication of every honey, being able to correctly label it with its botanical origin. Furthermore, the analysis was backed up by a mathematical analysis based on partial least square models which led to a correct classification rate of each type of honey of over 95%. Finally, the same approach was followed to analyze rice syrup, which is a common honey adulterant that is challenging to identify when mixed with honey. A LED-dependent and unique fluorescence spectrum was found for the syrup, which presumably qualifies this approach for the design of uncomplicated, fast, and cost-effective quality control and adulteration assessing tools for different types of honey. Copyright © 2018 Elsevier B.V. All rights reserved.

5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones: Zinc triflate-catalyzed one-pot multi-component synthesis, X-ray crystal structure and anti-inflammatory activity

NASA Astrophysics Data System (ADS)

Essid, Idris; Lahbib, Karima; Kaminsky, Werner; Ben Nasr, Cherif; Touil, Soufiane

2017-08-01

Herein we report a simple and efficient one-pot three-component synthesis of 5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones, through the zinc triflate-catalyzed Biginelli-type reaction of β-ketophosphonates, aldehydes and urea. The compounds obtained were characterized by various spectroscopic tools including IR, NMR (1H, 31P, 13C) spectroscopy, mass spectrometry and single crystal X-ray diffraction. All the synthesized compounds were screened, for the first time, for anti-inflammatory activity by carrageenan-induced hind paw edema method, using female Wister rats and they showed significant anti-inflammatory activity in some cases higher than the standard indomethacin.

Spectroscopic Studies of Pre-Biotic Carbon Chemistry

NASA Technical Reports Server (NTRS)

Blake, Geoffrey A.

2002-01-01

As described in the original proposal and in our progress reports, research in the Blake group supported by the Exobiology program seeks to understand the pre-biotic chemistry of carbon along with that of other first- and second-row elements from the earliest stages of star formation through the development of planetary systems. The major tool used is spectroscopy, and the program has observational, laboratory, and theoretical components. The observational and theoretical programs are concerned primarily with a quantitative assessment of the chemical budgets of the biogenic elements in star-forming molecular cloud cores, while the laboratory work is focused on the complex species that characterize the prebiotic chemistry of carbon. We outline below our results over the past two years acquired, in part, with Exobiology support.

Monitoring Cartilage Tissue Engineering Using Magnetic Resonance Spectroscopy, Imaging, and Elastography

PubMed Central

Klatt, Dieter; Magin, Richard L.

2013-01-01

A key technical challenge in cartilage tissue engineering is the development of a noninvasive method for monitoring the composition, structure, and function of the tissue at different growth stages. Due to its noninvasive, three-dimensional imaging capabilities and the breadth of available contrast mechanisms, magnetic resonance imaging (MRI) techniques can be expected to play a leading role in assessing engineered cartilage. In this review, we describe the new MR-based tools (spectroscopy, imaging, and elastography) that can provide quantitative biomarkers for cartilage tissue development both in vitro and in vivo. Magnetic resonance spectroscopy can identify the changing molecular structure and alternations in the conformation of major macromolecules (collagen and proteoglycans) using parameters such as chemical shift, relaxation rates, and magnetic spin couplings. MRI provides high-resolution images whose contrast reflects developing tissue microstructure and porosity through changes in local relaxation times and the apparent diffusion coefficient. Magnetic resonance elastography uses low-frequency mechanical vibrations in conjunction with MRI to measure soft tissue mechanical properties (shear modulus and viscosity). When combined, these three techniques provide a noninvasive, multiscale window for characterizing cartilage tissue growth at all stages of tissue development, from the initial cell seeding of scaffolds to the development of the extracellular matrix during construct incubation, and finally, to the postimplantation assessment of tissue integration in animals and patients. PMID:23574498

Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane—Breath Biomarkers of Serious Diseases

PubMed Central

Wojtas, Jacek

2015-01-01

The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (<3 s) were achieved. Absorption lines of reference samples of the selected volatile biomarkers were probed using a distributed feedback quantum cascade laser and a tunable laser system consisting of an optical parametric oscillator and difference frequency generator. Setup using the first source provided a detection limit of 30 ppb for nitric oxide and 250 ppb for carbonyl sulphide. During experiments employing a second laser, detection limits of 0.9 ppb and 0.3 ppb were obtained for carbonyl sulphide and ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases. PMID:26091398

Study of yttrium 4-nitrocinnamate to promote surface interactions with AS1020 steel

NASA Astrophysics Data System (ADS)

Hien, P. V.; Vu, N. S. H.; Thu, V. T. H.; Somers, A.; Nam, N. D.

2017-08-01

Yttrium 4-nitrocinnamate (Y(4-NO2Cin)3) was added to an aqueous chloride solution and studied as a possible corrosion inhibition system. Electrochemical techniques and surface analysis have been powerful tools to better understand the corrosion and inhibition processes of mild steel in 0.01 M NaCl solution. A combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Potentiodynamic polarization (PD), electrochemical impedance spectroscopy (EIS) and wire beam electrode (WBE) techniques was found to be useful in the characterization of this system. The result indicated that Y(4-NO2Cin)3 is able to effectively inhibit corrosion at a low concentration of 0.45 mM. Surface analysis clearly shows that the surface of steel coupons exposed to Y(4-NO2Cin)3 solution remained uniform and smooth, whereas the surface of steel coupons exposed to solution without inhibitor addition was severely corroded. The results suggest that Y(4-NO2Cin)3 behaves as a mixed inhibitor and mitigates corrosion by promoting random distribution of minor anodes. These are attributed to the formation of metal species bonding to the 4-nitrocinnamate component and hydrolysis of the Y(4-NO2Cin)3 to form oxide/hydroxides as a protective film layer.

New approaches to the analysis of complex samples using fluorescence lifetime techniques and organized media

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

Hertz, P.R.

Fluorescence spectroscopy is a highly sensitive and selective tool for the analysis of complex systems. In order to investigate the efficacy of several steady state and dynamic techniques for the analysis of complex systems, this work focuses on two types of complex, multicomponent samples: petrolatums and coal liquids. It is shown in these studies dynamic, fluorescence lifetime-based measurements provide enhanced discrimination between complex petrolatum samples. Additionally, improved quantitative analysis of multicomponent systems is demonstrated via incorporation of organized media in coal liquid samples. This research provides the first systematic studies of (1) multifrequency phase-resolved fluorescence spectroscopy for dynamic fluorescence spectralmore » fingerprinting of complex samples, and (2) the incorporation of bile salt micellar media to improve accuracy and sensitivity for characterization of complex systems. In the petroleum studies, phase-resolved fluorescence spectroscopy is used to combine spectral and lifetime information through the measurement of phase-resolved fluorescence intensity. The intensity is collected as a function of excitation and emission wavelengths, angular modulation frequency, and detector phase angle. This multidimensional information enhances the ability to distinguish between complex samples with similar spectral characteristics. Examination of the eigenvalues and eigenvectors from factor analysis of phase-resolved and steady state excitation-emission matrices, using chemometric methods of data analysis, confirms that phase-resolved fluorescence techniques offer improved discrimination between complex samples as compared with conventional steady state methods.« less

Probing Nitrosyl Ligation of Surface-Confined Metalloporphyrins by Inelastic Electron Tunneling Spectroscopy

PubMed Central

2013-01-01

Complexes obtained by the ligation of nitric oxide (NO) to metalloporphyrins represent important model systems with biological relevance. Herein we report a molecular-level investigation of surface-confined cobalt tetraphenyl porphyrin (Co-TPP) species and their interaction with NO under ultrahigh vacuum conditions. It is demonstrated that individual NO adducts can be desorbed using the atomically sharp tip of a scanning tunneling microscope, whereby a writing process is implemented for fully saturated regular metalloporphyrin arrays. The low-energy vibrational characteristics of individual Co-TPP-nitrosyl complexes probed by inelastic electron tunneling spectroscopy (IETS) reveal a prominent signature at an energy of ≃31 meV. Using density functional theory-based IETS simulations—the first to be performed on such an extensive interfacial nanosystem—we succeed to reproduce the low-frequency spectrum for the NO-ligated complex and explain the absence of IETS activity for bare Co-TPP. Moreover, we can conclusively assign the IETS peak of NO-Co-TPP to a unique vibration mode involving the NO complexation site, namely, the in-plane Co–N–O rocking mode. In addition, we verify that the propensity rules previously designed on small aromatic systems and molecular fragments hold true for a metal–organic entity. This work notably permits one to envisage IETS spectroscopy as a sensitive tool to chemically characterize hybrid interfaces formed by complex metal–organic units and gaseous adducts. PMID:23718257

Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane--Breath Biomarkers of Serious Diseases.

PubMed

Wojtas, Jacek

2015-06-17

The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (<3 s) were achieved. Absorption lines of reference samples of the selected volatile biomarkers were probed using a distributed feedback quantum cascade laser and a tunable laser system consisting of an optical parametric oscillator and difference frequency generator. Setup using the first source provided a detection limit of 30 ppb for nitric oxide and 250 ppb for carbonyl sulphide. During experiments employing a second laser, detection limits of 0.9 ppb and 0.3 ppb were obtained for carbonyl sulphide and ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases.

X-ray astronomical spectroscopy

NASA Technical Reports Server (NTRS)

Holt, S. S.

1980-01-01

The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

Species authentication and geographical origin discrimination of herbal medicines by near infrared spectroscopy: A review.

PubMed

Wang, Pei; Yu, Zhiguo

2015-10-01

Near infrared (NIR) spectroscopy as a rapid and nondestructive analytical technique, integrated with chemometrics, is a powerful process analytical tool for the pharmaceutical industry and is becoming an attractive complementary technique for herbal medicine analysis. This review mainly focuses on the recent applications of NIR spectroscopy in species authentication of herbal medicines and their geographical origin discrimination.

Synthesis and Characterization of Silicon Nanowires by Electroless Etching

NASA Astrophysics Data System (ADS)

Bhujel, Rabina; Rizal, Umesh; Agarwal, Amit; Swain, Bhabani S.; Swain, Bibhu P.

2018-02-01

Silicon nanowires (SiNWs) were synthesized by two-step electroless etching of p-type Si (100) wafer and characterized by field emission scanning electron microscopy, UV-Vis spectroscopy, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The vibrational signature at 1108 and 2087 cm-1 confirmed SiNWs were passivated by both oxygen and hydrogen atoms. Raman peak at 517 cm-1 indicated crystalline SiNWs with tailing toward redshift due to Fano effect. The Si(2p) and Si(2s) core orbital spectra of SiNWs were found at 99.8 and 150.5 eV, respectively. Moreover, the reflection of SiNWs is minimized to 1 to 5% in the 650-nm wavelength.

Application of THz Vibrational Spectroscopy to Molecular Characterization and the Theoretical Fundamentals: An Illustration Using Saccharide Molecules.

PubMed

Zhang, Feng; Wang, Houng-Wei; Tominaga, Keisuke; Hayashi, Michitoshi; Hasunuma, Tomohisa; Kondo, Akihiko

2017-02-01

This work illustrates several theoretical fundamentals for the application of THz vibrational spectroscopy to molecular characterization in the solid state using two different types of saccharide systems as examples. Four subjects have been specifically addressed: (1) the qualitative differences in the molecular vibrational signatures monitored by THz and mid-IR vibrational spectroscopy; (2) the selection rules for THz vibrational spectroscopy as applied to crystalline and amorphous systems; (3) a normal mode simulation, using α-l-xylose as an example; and (4) a rigorous mode analysis to quantify the percentage contributions of the intermolecular and intramolecular vibrations to the normal mode of interest. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterizing exposures to airborne metals and nanoparticle emissions in a refinery.

PubMed

Miller, Arthur; Drake, Pamela L; Hintz, Patrick; Habjan, Matt

2010-07-01

An air quality survey was conducted at a precious metals refinery in order to evaluate worker exposures to airborne metals and to provide detailed characterization of the aerosols. Two areas within the refinery were characterized: a furnace room and an electro-refining area. In line with standard survey practices, both personal and area air filter samples were collected on 37-mm filters and analyzed for metals by inductively coupled plasma-atomic emission spectroscopy. In addition to the standard sampling, measurements were conducted using other tools, designed to provide enhanced characterization of the workplace aerosols. The number concentration and number-weighted particle size distribution of airborne particles were measured with a fast mobility particle sizer (FMPS). Custom-designed software was used to correlate particle concentration data with spatial location data to generate contour maps of particle number concentrations in the work areas. Short-term samples were collected in areas of localized high concentrations and analyzed using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) to determine particle morphology and elemental chemistry. Analysis of filter samples indicated that all of the workers were exposed to levels of silver above the Occupational Safety and Health Administration permissible exposure limit of 0.01 mg m(-3) even though the localized ventilation was functioning. Measurements with the FMPS indicated that particle number concentrations near the furnace increased up to 1000-fold above the baseline during the pouring of molten metal. Spatial mapping revealed localized elevated particle concentrations near the furnaces and plumes of particles rising into the stairwells and traveling to the upper work areas. Results of TEM/EDS analyses confirmed the high number of nanoparticles measured by the FMPS and indicated the aerosols were rich in metals including silver, lead, antimony, selenium, and zinc. Results of the survey were used to deduce appropriate strategies for mitigation of worker exposure to airborne metals.

Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

PubMed Central

Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

2015-01-01

The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

Characterization of CuHal-intercalated carbon nanotubes with x-ray absorption spectroscopy combined with x-ray photoelectron and resonant photoemission spectroscopies

NASA Astrophysics Data System (ADS)

Brzhezinskaya, M.; Generalov, A.; Vinogdradov, A.; Eliseev, A.

2013-04-01

Encapsulated single-walled carbon nanotubes (SWCNTs) with inner channels filled by different compounds present the new class of composite materials. Such CNTs give opportunity to form 1D nanocrystals as well as quantum nanowires with new physical and chemical properties inside the tubes. The present study is aimed to characterize the possible chemical interaction between CuHal (Hal=I, Cl, Br) and SWCNTs in CuHal@SWCNTs and electronic structure of the latter using high-resolution near edge X-ray absorption fine structure (NEXAFS) spectroscopy combined with high-resolution X-ray photoelectron spectroscopy and resonant photoemission spectroscopy. The present study has shown that there is a chemical interaction between the filler and π-electron subsystem of CNTs which is accompanied by changes of the atomic and electronic structure of the filler during the encapsulating it inside CNTs.

Review of functional near-infrared spectroscopy in neurorehabilitation

PubMed Central

Mihara, Masahito; Miyai, Ichiro

2016-01-01

Abstract. We provide a brief overview of the research and clinical applications of near-infrared spectroscopy (NIRS) in the neurorehabilitation field. NIRS has several potential advantages and shortcomings as a neuroimaging tool and is suitable for research application in the rehabilitation field. As one of the main applications of NIRS, we discuss its application as a monitoring tool, including investigating the neural mechanism of functional recovery after brain damage and investigating the neural mechanisms for controlling bipedal locomotion and postural balance in humans. In addition to being a monitoring tool, advances in signal processing techniques allow us to use NIRS as a therapeutic tool in this field. With a brief summary of recent studies investigating the clinical application of NIRS using motor imagery task, we discuss the possible clinical usage of NIRS in brain–computer interface and neurofeedback. PMID:27429995

Using Modern And Inexpensive Tools In the Classroom To Teach Spectroscopy And To Do Exciting Citizen Science On Astronomical Objects

NASA Astrophysics Data System (ADS)

Field, T.

2014-12-01

Spectroscopy is a key tool used in modern astronomical research. But, it's always been a difficult topic to teach or practice because the expense and complexity of the available tools. Over the past few years, there's been somewhat of a revolution in this field as new technologies have applied. In this presentation we'll review some new spectroscopy tools that enable educators, students and citizen scientists to do exciting spectroscopic work. With the addition of a simple, inexpensive grating, it's now possible to capture scientifically significant spectra of astronomical objects with small (6") telescopes and even just a DSLR. See the tools that citizen scientists are using to contribute data to pro-am collaborations around the world. We'll also examine a simple, surprisingly inexpensive, tripod-mounted spectrometer that can be used in the classroom for demonstrations and hands-on labs with gas tubes and other light sources. Both of the above instruments use a software program named RSpec, which is state of the art software suite that is easy to learn and easy to use. In this presentation we'll see these devices in operation and discuss how they can be used by educators to dramatically improve their teaching of this topic. You'll see how these tools can eliminate the frustration of hand-held rainbow foil and plastic spectrometers. And we'll review some exciting examples of astronomical spectra being collected by amateurs and educators.

RAMAN SPECTROSCOPY-BASED METABOLOMICS FOR DIFFERENTIATING EXPOSURES TO TRIAZOLE FUNGICIDES USING RAT URINE

EPA Science Inventory

Normal Raman spectroscopy was evaluated as a metabolomic tool for assessing the impacts of exposure to environmental contaminants, using rat urine collected during the course of a toxicological study. Specifically, one of three triazole fungicides, myclobutanil, propiconazole or ...

MULTIVARIATE CURVE RESOLUTION OF NMR SPECTROSCOPY METABONOMIC DATA

EPA Science Inventory

Sandia National Laboratories is working with the EPA to evaluate and develop mathematical tools for analysis of the collected NMR spectroscopy data. Initially, we have focused on the use of Multivariate Curve Resolution (MCR) also known as molecular factor analysis (MFA), a tech...

Interphase evolution at two promising electrode materials for Li-ion batteries: LiFePO4 and LiNi1/2 Mn1/2O2.

PubMed

Dupré, Nicolas; Cuisinier, Marine; Martin, Jean-Frederic; Guyomard, Dominique

2014-07-21

The present review reports the characterization and control of interfacial processes occurring on olivine LiFePO(4) and layered LiNi(1/2) Mn(1/2)O(2), standing here as model compounds, during storage and electrochemical cycling. The formation and evolution of the interphase created by decomposition of the electrolyte is investigated by using spectroscopic tools such as magic-angle-spinning nuclear magnetic resonance ((7)Li,(19)F and (31)P) and electron energy loss spectroscopy, in parallel to X-ray photoelectron spectroscopy, to quantitatively describe the interphase and unravel its architecture. The influence of the pristine surface chemistry of the active material is carefully examined. The importance of the chemical history of the surface of the electrode material before any electrochemical cycling and the strong correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior appear clearly from the use of these combined characterization probes. This approach allows identifying interface aging and failure mechanisms. Different types of surface modifications are then investigated, such as intrinsic modifications upon aging in air or methods based on the use of additives in the electrolyte or carbon coatings on the surface of the active materials. In each case, the species detected on the surface of the materials during storage and cycling are correlated with the electrochemical performance of the modified positive electrodes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of point defects in monolayer arsenene

NASA Astrophysics Data System (ADS)

Liang, Xiongyi; Ng, Siu-Pang; Ding, Ning; Wu, Chi-Man Lawrence

2018-06-01

Topological defects that are inevitably found in 2D materials can dramatically affect their properties. Using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) method, the structural, thermodynamic, electronic and magnetic properties of six types of typical point defects in arsenene, i.e. the Stone-Wales defect, single and double vacancies and adatoms, were systemically studied. It was found that these defects were all more easily generated in arsenene with lower formation energies than those with graphene and silicene. Stone-Wales defects can be transformed from pristine arsenene by overcoming a barrier of 2.19 eV and single vacancy defects tend to coalesce into double vacancy defects by diffusion. However, a type of adatom defect does not exhibit kinetic stability at room temperature. In addition, SV defects and another type of adatom defect can remarkably affect the electronic and magnetic properties of arsenene, e.g. they can introduce localized states near the Fermi level, as well as a strongly local magnetic moment due to dangling bond and unpaired electron. Furthermore, the simulated scanning tunneling microscopy (STM) and Raman spectroscopy were computed and the types of point defects can be fully characterized by correlating the STM images and Raman spectra to the defective atomistic structures. The results provide significant insights to the effect of defects in arsenene for potential applications, as well as identifications of two helpful tools (STM and Raman spectroscopy) to distinguish the type of defects in arsenene for future experiments.

In vivo swine myocardial tissue characterization and monitoring during open chest surgery by time-resolved diffuse near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Spinelli, Lorenzo; Contini, Davide; Farina, Andrea; Torricelli, Alessandro; Pifferi, Antonio; Cubeddu, Rinaldo; Ascari, Luca; Potì, Luca; Trivella, Maria Giovanna; L'Abbate, Antonio; Puzzuoli, Stefano

2011-03-01

Cardiovascular diseases are the main cause of death in industrialized countries. Worldwide, a large number of patients suffering from cardiac diseases are treated by surgery. Despite the advances achieved in the last decades with myocardial protection, surgical failure can still occur. This is due at least in part to the imperfect control of the metabolic status of the heart in the various phases of surgical intervention. At present, this is indirectly controlled by the electrocardiogram and the echographic monitoring of cardiac mechanics as direct measurements are lacking. Diffuse optical technologies have recently emerged as promising tools for the characterization of biological tissues like breast, muscles and bone, and for the monitoring of important metabolic parameters such as blood oxygenation, volume and flow. As a matter of fact, their utility has been demonstrated in a variety of applications for functional imaging of the brain, optical mammography and monitoring of muscle metabolism. However, due to technological and practical difficulties, their potential for cardiac monitoring has not yet been exploited. In this work we show the feasibility of the in-vivo determination of absorption and scattering spectra of the cardiac muscle in the 600-1100 nm range, and of monitoring myocardial tissue hemodynamics by time domain near-infrared spectroscopy at 690 nm and 830 nm. Both measurements have been performed on the exposed beating heart during open chest surgery in pigs, an experimental model closely mimicking the clinical cardio-surgical setting.

Characterization of photo-induced valence tautomerism in a cobalt-dioxolene complex by ultrafast spectroscopy

NASA Astrophysics Data System (ADS)

Beni, A.; Bogani, L.; Bussotti, L.; Dei, A.; Gentili, P. L.; Righini, R.

2005-01-01

The valence tautomerism of low-spin CoIII(Cat-N-BQ)(Cat-N-SQ) was investigated by means of UV-vis pump-probe transient absorption spectroscopy in chloroform. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin CoII(Cat-N-BQ)2 that, secondly, reaches the chemical equilibrium with the reactant species.

Consistent characterization of semiconductor saturable absorber mirrors with single-pulse and pump-probe spectroscopy.

PubMed

Fleischhaker, R; Krauss, N; Schättiger, F; Dekorsy, T

2013-03-25

We study the comparability of the two most important measurement methods used for the characterization of semiconductor saturable absorber mirrors (SESAMs). For both methods, single-pulse spectroscopy (SPS) and pump-probe spectroscopy (PPS), we analyze in detail the time-dependent saturation dynamics inside a SESAM. Based on this analysis, we find that fluence-dependent PPS at complete spatial overlap and zero time delay is equivalent to SPS. We confirm our findings experimentally by comparing data from SPS and PPS of two samples. We show how to interpret this data consistently and we give explanations for possible deviations.

In-line NIR spectroscopy for the understanding of polymer-drug interaction during pharmaceutical hot-melt extrusion.

PubMed

Saerens, Lien; Dierickx, Lien; Quinten, Thomas; Adriaensens, Peter; Carleer, Robert; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

2012-05-01

The aim was to evaluate near-infrared spectroscopy for the in-line determination of the drug concentration, the polymer-drug solid-state behaviour and molecular interactions during hot-melt extrusion. Kollidon® SR was extruded with varying metoprolol tartrate (MPT) concentrations (20%, 30% and 40%) and monitored using NIR spectroscopy. A PLS model allowed drug concentration determination. The correlation between predicted and real MPT concentrations was good (R(2)=0.97). The predictive performance of the model was evaluated by the root mean square error of prediction, which was 1.54%. Kollidon® SR with 40% MPT was extruded at 105°C and 135°C to evaluate NIR spectroscopy for in-line polymer-drug solid-state characterisation. NIR spectra indicated the presence of amorphous MPT and hydrogen bonds between drug and polymer in the extrudates. More amorphous MPT and interactions could be found in the extrudates produced at 135°C than at 105°C. Raman spectroscopy, DSC and ATR FT-IR were used to confirm the NIR observations. Due to the instability of the formulation, only in-line Raman spectroscopy was an adequate confirmation tool. NIR spectroscopy is a potential PAT-tool for the in-line determination of API concentration and for the polymer-drug solid-state behaviour monitoring during pharmaceutical hot-melt extrusion. Copyright © 2012 Elsevier B.V. All rights reserved.

Using polarized Raman spectroscopy and the pseudospectral method to characterize molecular structure and function

NASA Astrophysics Data System (ADS)

Weisman, Andrew L.

Electronic structure calculation is an essential approach for determining the structure and function of molecules and is therefore of critical interest to physics, chemistry, and materials science. Of the various algorithms for calculating electronic structure, the pseudospectral method is among the fastest. However, the trade-off for its speed is more up-front programming and testing, and as a result, applications using the pseudospectral method currently lag behind those using other methods. In Part I of this dissertation, we first advance the pseudospectral method by optimizing it for an important application, polarized Raman spectroscopy, which is a well-established tool used to characterize molecular properties. This is an application of particular importance because often the easiest and most economical way to obtain the polarized Raman spectrum of a material is to simulate it; thus, utilization of the pseudospectral method for this purpose will accelerate progress in the determination of molecular properties. We demonstrate that our implementation of Raman spectroscopy using the pseudospectral method results in spectra that are just as accurate as those calculated using the traditional analytic method, and in the process, we derive the most comprehensive formulation to date of polarized Raman intensity formulas, applicable to both crystalline and isotropic systems. Next, we apply our implementation to determine the orientations of crystalline oligothiophenes -- a class of materials important in the field of organic electronics -- achieving excellent agreement with experiment and demonstrating the general utility of polarized Raman spectroscopy for the determination of crystal orientation. In addition, we derive from first-principles a method for using polarized Raman spectra to establish unambiguously whether a uniform region of a material is crystalline or isotropic. Finally, we introduce free, open-source software that allows a user to determine any of a number of polarized Raman properties of a sample given common output from electronic structure calculations. In Part II, we apply the pseudospectral method to other areas of scientific importance requiring a deeper understanding of molecular structure and function. First, we use it to accurately determine the frequencies of vibrational tags on biomolecules that can be detected in real-time using stimulated Raman spectroscopy. Next, we evaluate the performance of the pseudospectral method for calculating excited-state energies and energy gradients of large molecules -- another new application of the pseudospectral method -- showing that the calculations run much more quickly than those using the analytic method. Finally, we use the pseudospectral method to simulate the bottleneck process of a solar cell used for water splitting, a promising technology for converting the sun's energy into hydrogen fuel. We apply the speed of the pseudospectral method by modeling the relevant part of the system as a large, explicitly passivated titanium dioxide nanoparticle and simulating it realistically using hybrid density functional theory with an implicit solvent model, yielding insight into the physical nature of the rate-limiting step of water splitting. These results further validate the particularly fast and accurate simulation methodologies used, opening the door to efficient and realistic cluster-based, fully quantum-mechanical simulations of the bottleneck process of a promising technology for clean solar energy conversion. Taken together, we show how both polarized Raman spectroscopy and the pseudospectral method are effective tools for analyzing the structure and function of important molecular systems.

The Use of UV-Visible Reflectance Spectroscopy as an Objective Tool to Evaluate Pearl Quality

PubMed Central

Agatonovic-Kustrin, Snezana; Morton, David W.

2012-01-01

Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl’s quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry. PMID:22851919

Coherent Raman spectroscopies for measuring molecular flow velocity

NASA Technical Reports Server (NTRS)

She, C. Y.

1982-01-01

Various types of coherent Raman spectroscopy are characterized and their application to molecular flow velocity and direction measurement and species concentration and temperature determination is discussed.

The SuperCam Remote Sensing Suite for MARS 2020: Nested and Co-Aligned LIBS, Raman, and VISIR Spectroscopies, and color micro-imaging

NASA Astrophysics Data System (ADS)

Fouchet, Thierry; Wiens, Roger; Maurice, Sylvestre; Johnson, Jeffrey R.; Clegg, Samuel; Sharma, Shiv; Rull, Fernando; Montmessin, Franck; Anderson, Ryan; Beyssac, Olivier; Bonal, Lydie; Deflores, Lauren; Dromart, Gilles; Fischer, William; Forni, Olivier; Gasnault, Olivier; Grotzinger, John P.; Mangold, Nicolas; Martinez-Frias, Jesus; MacLennan, Scott; McCabe, Kevin; cais, Philippe; Nelson, Tony; Angel, Stanley; Beck, Pierre; Benzerara, Karim; Bernard, Sylvain; Bousquet, Bruno; Bridges, Nathan; Cloutis, Edward; Fabre, Cécile; Grasset, Olivier; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Leveille, Rich; Lewin, Eric; McConnochie, Timothy H.; Melikechi, Noureddine; Meslin, Pierre-Yves; Misra, Anupam; Montagnac, Gilles; Newsom, Horton; Ollila, Ann; Pinet, Patrick; Poulet, Francois; Sobron, Pablo

2016-10-01

As chartered by the Science Definition Team, the Mars 2020 mission addresses four primary objectives: A. Characterize the processes that formed and modified the geologic record within an astrobiologically relevant ancient environment, B. Perform astrobiologically relevant investigations to determine habitability, search for materials with biosignature presentation potential, and search for evidence of past life, C. Assemble a returnable cache of samples and D. Contribute to preparation for human exploration of Mars. The SuperCam instrument, selected for the Mars 2020 rover, as a suite of four instruments, provides nested and co-aligned remote investigations: Laser Induced Breakdown Spectroscopy (LIBS), Raman spectroscopy and time-resolved fluorescence (TRF), visible and near-infrared spectroscopy (VISIR), and high resolution color imaging (RMI). SuperCam appeals broadly to the four Mars 2020 objectives.In detail, SuperCam will perform:1. Microscale mineral identification by combining LIBS elemental and VISIR mineralogical spectroscopies, especially targeting secondary minerals2. Determine the sedimental stratigraphy through color imaging and LIBS and VISIR spectroscopy3. Search for organics and bio-signatures with LIBS and Raman spectroscopy4. Quantify the volatile content of the rocks by LIBS spectroscopy to determine the degree of aquaeous alteration5. Characterize the texture of the rocks by color imaging to determine their alteration processes6. Characterize the rocks' coatings by LIBS spectroscopy7. Characterize the soil and its potential for biosignature preservation8. Monitor the odd-oxygen atmospheric chemistry.To meet these goals SuperCam will perform LIBS spectroscopy on 0.5 mm spot up to 7-meter distance, perform Raman and time-resolved fluoresence up to 12-m distance with a 0.8 mrad angular resolution, a 100 ns time gating in the 534-850 nm spectral range, acquire VISIR spectra in the range 0.4-0.85 μm with a resolution of 0.35 nm, and in the IR range over 1.3-2.6 μm, rich in mineral signatures, with a resolution of 20 nm, and provide RGB images with an angular resolution of 40 μrad over a FOV of 20 mrad.We will present the science performances of SuperCam and the forecasted operation plans.

Stand-Alone Measurements and Characterization | Photovoltaic Research |

Science.gov Websites

Science and Technology Facility cluster tools offer powerful capabilities for measuring and characterizing Characterization tool suite are supplemented by the Integrated Measurements and Characterization cluster tool the Integrated M&C cluster tool using a mobile transport pod, which can keep samples under vacuum

Fourier Transform Infrared Spectroscopy as a Tool in Analysis of Proteus mirabilis Endotoxins.

PubMed

Żarnowiec, Paulina; Czerwonka, Grzegorz; Kaca, Wiesław

2017-01-01

Fourier transform infrared spectroscopy (FT-IR) was used to scan whole bacterial cells as well as lipopolysaccharides (LPSs, endotoxins) isolated from them. Proteus mirabilis cells, with chemically defined LPSs, served as a model for the ATR FT-IR method. The paper focuses on three steps of infrared spectroscopy: (1) sample preparation, (2) IR scanning, and (3) multivariate analysis of IR data (principal component analysis, PCA).

THE ROLE OF RAMAN SPECTROSCOPY IN THE ANALYTICAL CHEMISTRY OF POTABLE WATER

EPA Science Inventory

Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of chemical applications. For example, many recalcitrant industrial-process monitoring problems have been solved in recent years with in-line Raman spectrometers. Raman is attr...

THE ROLE OF RAMAN SPECTROSCOPY IN THE ANALYTICAL CHEMISTRY OF POTABLE WATER

EPA Science Inventory

Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of chemical applications. For example, many recalcitrant industrial process monitoring problems have been solved in recent years with in-line Raman spectrometers. Raman is attr...

Planar diode multiplier chains for THz spectroscopy

NASA Technical Reports Server (NTRS)

Maiwald, Frank W.; Drouin, Brian J.; Pearson, John C.; Mehdi, Imran; Lewena, Frank; Endres, Christian; Winnewisser, Gisbert

2005-01-01

High-resolution laboratory spectroscopy is utilized as a diagnostic tool to determine noise and harmonic content of balanced [9]-[11] and unbalanced [12]-[14] multiplier designs. Balanced multiplier designs suppress unintended harmonics more than -20dB. Much smaller values were measured on unbalanced multipliers.

Soil texture and organic carbon fractions predicted from near-infrared spectroscopy and geostatistics

USDA-ARS?s Scientific Manuscript database

Field-specific management could help achieve agricultural sustainability by increasing production and decreasing environmental impacts. Near-infrared spectroscopy (NIRS) and geostatistics are relatively unexplored tools that could reduce time, labor, and costs of soil analysis. Our objective was to ...

Online UV-visible spectroscopy and multivariate curve resolution as powerful tool for model-free investigation of laccase-catalysed oxidation.

PubMed

Kandelbauer, A; Kessler, W; Kessler, R W

2008-03-01

The laccase-catalysed transformation of indigo carmine (IC) with and without a redox active mediator was studied using online UV-visible spectroscopy. Deconvolution of the mixture spectra obtained during the reaction was performed on a model-free basis using multivariate curve resolution (MCR). Thereby, the time courses of educts, products, and reaction intermediates involved in the transformation were reconstructed without prior mechanistic assumptions. Furthermore, the spectral signature of a reactive intermediate which could not have been detected by a classical hard-modelling approach was extracted from the chemometric analysis. The findings suggest that the combined use of UV-visible spectroscopy and MCR may lead to unexpectedly deep mechanistic evidence otherwise buried in the experimental data. Thus, although rather an unspecific method, UV-visible spectroscopy can prove useful in the monitoring of chemical reactions when combined with MCR. This offers a wide range of chemists a cheap and readily available, highly sensitive tool for chemical reaction online monitoring.

X-ray techniques for innovation in industry

PubMed Central

Lawniczak-Jablonska, Krystyna; Cutler, Jeffrey

2014-01-01

The smart specialization declared in the European program Horizon 2020, and the increasing cooperation between research and development found in companies and researchers at universities and research institutions have created a new paradigm where many calls for proposals require participation and funding from public and private entities. This has created a unique opportunity for large-scale facilities, such as synchrotron research laboratories, to participate in and support applied research programs. Scientific staff at synchrotron facilities have developed many advanced tools that make optimal use of the characteristics of the light generated by the storage ring. These tools have been exceptionally valuable for materials characterization including X-ray absorption spectroscopy, diffraction, tomography and scattering, and have been key in solving many research and development issues. Progress in optics and detectors, as well as a large effort put into the improvement of data analysis codes, have resulted in the development of reliable and reproducible procedures for materials characterization. Research with photons has contributed to the development of a wide variety of products such as plastics, cosmetics, chemicals, building materials, packaging materials and pharma. In this review, a few examples are highlighted of successful cooperation leading to solutions of a variety of industrial technological problems which have been exploited by industry including lessons learned from the Science Link project, supported by the European Commission, as a new approach to increase the number of commercial users at large-scale research infrastructures. PMID:25485139

Development of zinc oxide nanoparticle by sonochemical method and study of their physical and optical properties

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

Khan, Samreen Heena, E-mail: samreen.heena.khan@gmail.com; Suriyaprabha, R.; Pathak, Bhawana, E-mail: bhawana.pathak@cug.ac.in

With the miniaturization of crystal size, the fraction of under-coordinated surface atoms becomes dominant, and hence, materials in the nano-regime behave very differently from the similar material in a bulk. Zinc oxide (ZnO), particularly, exhibits extraordinary properties such as a wide direct band gap (3.37 eV), large excitation binding energy (60 meV), low refractive index (1.9), stability to intense ultraviolet (UV) illumination, resistance to high-energy irradiation, and lower toxicity as compared to other semiconductors. This very property makes Zinc Oxide a potential candidate in many application fields, particularly as a prominent semiconductor. Zinc Oxide plays a significant role in manymore » technological advances with its application in semiconductor mediated photocatalytic processes and sensor, solar cells and others. In present study, Zinc Oxide (ZnO) has been synthesized using three different precursors by sonochemical method. Zinc Acetate Dihydrate, Zinc Nitrate Hexahydrate and Zinc Sulphate Heptahydrate used as a precursor for the synthesis process. The synthesized ZnO nanoparticle has been found under the range of ∼50 nm. Zinc oxide nanoparticles were characterized using different characterizing tools. The as-synthesized ZnO was characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) for the determination of functional group; Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS) for Morphology and elemental detection respectively, Transmission Electron Microscopy for Particle size distribution and morphology and X-Ray Diffraction (XRD) for the confirmation of crystal structure of the nanomaterial. The optical properties of the ZnO were examined by UV-VIS spectroscopy equipped with Diffuse Reflectance spectroscopy (DRS) confirmed the optical band gap of ZnO-3 around 3.23 eV resembles with the band gap of bulk ZnO (3.37eV). The TEM micrograph of the as-synthesized material showed perfectly spherical shaped nanoparticle under the size range of 50nm. The XRD data showed that the ZnO-3 which was synthesized using Zinc Nitrate Hexahydrate as precursor showed the hexagonal wurtzite crystal structure. The XRD data obtained were compared with the JCPDS standard data. The precursor Zinc Nitrate Hexahydrate (ZnO-3) showed the good yield, monodispersity and size of nanoparticle under the range of 50 nm. The ZnO nanoparticles synthesize using different precursor was found effective in order of ZnO-3, followed by ZnO-1 & ZnO-2. The Synthesized ZnO has wider application in environmental remediation and clean-up as a potential nano-catalyst.« less

Growth and characterization of amorphous selenium: An exploration into the glass transition temperature

NASA Astrophysics Data System (ADS)

Schaefers, Justin Kyle

The glass transition temperature (Tg) of alpha-Se films and its correlation to percent As inclusion was explored using such characterization tools as Raman spectroscopy, spectroscopic ellipsometry, atomic force microscopy, and microphotography. The films were deposited under ultra high vacuum conditions in a dedicated molecular beam epitaxy chamber onto semi-insulating GaAs (100) substrates. After deposition, the samples were thermally annealed in 5°C increments until they began to crystallize, as evident in the characterizations performed. It was discovered that not only is Tg directly related to percent As, but that the film thickness is as well. Higher than previously reported values, Tg was found to be 80°C for 0% As, 110°C for 2% As, and 125°C for 5% As. In addition, instead of producing polycrystalline films containing all the allotropes of Se as a result of the annealing process, films of the trigonal allotrope of crystalline selenium (t-Se) were produced through the annealing process. The transition from the amorphous phase to the trigonal phase has never been reported prior to this dissertation. Finally, it was also discovered that the MBE deposition of the films is truly epitaxial in nature.

integrating Solid State NMR and Computations in Membrane Protein Science

NASA Astrophysics Data System (ADS)

Cross, Timothy

2015-03-01

Helical membrane protein structures are influenced by their native environment. Therefore the characterization of their structure in an environment that models as closely as possible their native environment is critical for achieving not only structural but functional understanding of these proteins. Solid state NMR spectroscopy in liquid crystalline lipid bilayers provides an excellent tool for such characterizations. Two classes of restraints can be obtained - absolute restraints that constrain the structure to a laboratory frame of reference when using uniformly oriented samples (approximately 1° of mosaic spread) and relative restraints that restrain one part of the structure with respect to another part such as torsional and distance restraints. Here, I will discuss unique restraints derived from uniformly oriented samples and the characterization of initial structures utilizing both restraint types, followed by restrained molecular dynamics refinement in the same lipid bilayer environment as that used for the experimental restraint collection. Protein examples will be taken from Influenza virus and Mycobacterium tuberculosis. When available comparisons of structures to those obtained using different membrane mimetic environments will be shown and the causes for structural distortions explained based on an understanding of membrane biophysics and its sophisticated influence on membrane proteins.

Positron annihilation spectroscopy: Applications to Si, ZnO, and multilayer semiconductor structures

NASA Astrophysics Data System (ADS)

Schaffer, J. P.; Rohatgi, A.; Dewald, A. B.; Frost, R. L.; Pang, S. K.

1989-11-01

The potential of positron annihilation spectroscopy (PAS) for defect characterization at the atomic scale in semiconductors is demonstrated for Si, ZnO, and multilayer structures, such as an AlGaAs/GaAs solar cell. The types of defects discussed include: i) vacancy complexes, oxygen impurities and dopants, ii) the influence of cooling rates on spatial non-uniformities in defects, and iii) characterization of buried interfaces. In sev-eral instances, the results of the PAS investigations are correlated with data from other established semiconductor characterization techniques.

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.

Auger electron spectroscopy, secondary ion mass spectroscopy and optical characterization of a-C-H and BN films

NASA Technical Reports Server (NTRS)

Pouch, J. J.; Alterovitz, S. A.; Warner, J. D.

1986-01-01

The amorphous dielectrics a-C:H and BN were deposited on III-V semiconductors. Optical band gaps as high as 3 eV were measured for a-C:H generated by C4H10 plasmas; a comparison was made with bad gaps obtained from films prepared by CH4 glow discharges. The ion beam deposited BN films exhibited amorphous behavior with band gaps on the order of 5 eV. Film compositions were studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The optical properties were characterized by ellipsometry, UV/VIS absorption, and IR reflection and transmission. Etching rates of a-C:H subjected to O2 dicharges were determined.

Atomic Force Microscopy: A Powerful Tool to Address Scaffold Design in Tissue Engineering.

PubMed

Marrese, Marica; Guarino, Vincenzo; Ambrosio, Luigi

2017-02-13

Functional polymers currently represent a basic component of a large range of biological and biomedical applications including molecular release, tissue engineering, bio-sensing and medical imaging. Advancements in these fields are driven by the use of a wide set of biodegradable polymers with controlled physical and bio-interactive properties. In this context, microscopy techniques such as Atomic Force Microscopy (AFM) are emerging as fundamental tools to deeply investigate morphology and structural properties at micro and sub-micrometric scale, in order to evaluate the in time relationship between physicochemical properties of biomaterials and biological response. In particular, AFM is not only a mere tool for screening surface topography, but may offer a significant contribution to understand surface and interface properties, thus concurring to the optimization of biomaterials performance, processes, physical and chemical properties at the micro and nanoscale. This is possible by capitalizing the recent discoveries in nanotechnologies applied to soft matter such as atomic force spectroscopy to measure surface forces through force curves. By tip-sample local interactions, several information can be collected such as elasticity, viscoelasticity, surface charge densities and wettability. This paper overviews recent developments in AFM technology and imaging techniques by remarking differences in operational modes, the implementation of advanced tools and their current application in biomaterials science, in terms of characterization of polymeric devices in different forms (i.e., fibres, films or particles).

A Quantitative Infrared Spectroscopy Experiment.

ERIC Educational Resources Information Center

Krahling, Mark D.; Eliason, Robert

1985-01-01

Although infrared spectroscopy is used primarily for qualitative identifications, it is possible to use it as a quantitative tool as well. The use of a standard curve to determine percent methanol in a 2,2,2-trifluoroethanol sample is described. Background information, experimental procedures, and results obtained are provided. (JN)

NIRS-SPM: statistical parametric mapping for near infrared spectroscopy

NASA Astrophysics Data System (ADS)

Tak, Sungho; Jang, Kwang Eun; Jung, Jinwook; Jang, Jaeduck; Jeong, Yong; Ye, Jong Chul

2008-02-01

Even though there exists a powerful statistical parametric mapping (SPM) tool for fMRI, similar public domain tools are not available for near infrared spectroscopy (NIRS). In this paper, we describe a new public domain statistical toolbox called NIRS-SPM for quantitative analysis of NIRS signals. Specifically, NIRS-SPM statistically analyzes the NIRS data using GLM and makes inference as the excursion probability which comes from the random field that are interpolated from the sparse measurement. In order to obtain correct inference, NIRS-SPM offers the pre-coloring and pre-whitening method for temporal correlation estimation. For simultaneous recording NIRS signal with fMRI, the spatial mapping between fMRI image and real coordinate in 3-D digitizer is estimated using Horn's algorithm. These powerful tools allows us the super-resolution localization of the brain activation which is not possible using the conventional NIRS analysis tools.

Synthesis, physicochemical and optical properties of bis-thiosemicarbazone functionalized graphene oxide

NASA Astrophysics Data System (ADS)

Kumar, Santosh; Wani, Mohmmad Y.; Arranja, Claudia T.; Castro, Ricardo A. E.; Paixão, José A.; Sobral, Abilio J. F. N.

2018-01-01

Fluorescent materials are important for low-cost opto-electronic and biomedical sensor devices. In this study we present the synthesis and characterization of graphene modified with bis-thiosemicarbazone (BTS). This new material was characterized using Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible (UV-Vis) and Raman spectroscopy techniques. Further evaluation by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic-force microscopy (AFM) allowed us to fully characterize the morphology of the fabricated material. The average height of the BTSGO sheet is around 10 nm. Optical properties of BTSGO evaluated by photoluminescence (PL) spectroscopy showed red shift at different excitation wavelength compared to graphene oxide or bisthiosemicarbazide alone. These results strongly suggest that BTSGO material could find potential applications in graphene based optoelectronic devices.

Optical characterization of glutamate dehydrogenase monolayers chemisorbed on SiO2

NASA Astrophysics Data System (ADS)

Pompa, P. P.; Blasi, L.; Longo, L.; Cingolani, R.; Ciccarella, G.; Vasapollo, G.; Rinaldi, R.; Rizzello, A.; Storelli, C.; Maffia, M.

2003-04-01

This paper describes the formation of glutamate dehydrogenase monolayers on silicon dioxide, and their characterization by means of physical techniques, i.e., fluorescence spectroscopy and Fourier-transform infrared spectroscopy. Detailed investigations of the intrinsic stability of native proteins in solution were carried out to elucidate the occurrence of conformational changes induced by the immobilization procedure. The enzyme monolayers were deposited on SiO2 after preexposing silicon surfaces to 3-aminopropyltriethoxysilane and reacting the silylated surfaces with glutaric dialdehyde. The optical characterization demonstrates that the immobilization does not interfere with the fold pattern of the native enzyme. In addition, fluorescence spectroscopy, thermal denaturation, and quenching studies performed on the enzyme in solution well describe the folding and unfolding properties of glutamate dehydrogenase. The photophysical studies reported here are relevant for nanobioelectronics applications requiring protein immobilization on a chip.

Characterization of a Continuous Wave Laser for Resonance Ionization Mass Spectroscopy Analysis in Nuclear Forensics

DTIC Science & Technology

2015-06-01

OF A CONTINUOUS WAVE LASER FOR RESONANCE IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS by Sunny G. Lau June 2015 Thesis...IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS 5. FUNDING NUMBERS 6. AUTHOR(S) Sunny G. Lau 7. PERFORMING ORGANIZATION NAME(S) AND...200 words) The application of resonance ionization mass spectroscopy (RIMS) to nuclear forensics involves the use of lasers to selectively ionize

Resonant ultrasound spectroscopy

DOEpatents

Migliori, Albert

1991-01-01

A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

Chemical bath deposition of semiconductor thin films & nanostructures in novel microreactors

NASA Astrophysics Data System (ADS)

McPeak, Kevin M.

Chemical bath deposition (CBD) offers a simple and inexpensive route to deposit semiconductor nanostructures and thin films, but lack of fundamental understanding and control of the underlying chemistry has limited its versatility. CBD is traditionally performed in a batch reactor, requiring only a substrate to be immersed in a supersaturated solution of aqueous precursors such as metal salts, complexing agents, and pH buffers. Highlights of CBD include low cost, operation at low temperature and atmospheric pressure, and scalability to large area substrates. In this dissertation, I explore CBD of semiconductor thin films and nanowire arrays in batch and continuous flow microreactors. Microreactors offer many advantages over traditional reactor designs including a reduction in mass transport limitations, precise temperature control and ease of production scale-up by "numbering up". Continuous flow micoreactors offer the unique advantage of providing reaction conditions that are time-invariant but change smoothly as a function of distance down the reaction channel. Growth from a bath whose composition changes along the reactor length results in deposited materials whose properties vary as a function of position on the substrate, essentially creating a combinatorial library. These substrates can be rapidly characterized to identify relationships between growth conditions and material properties or growth mechanisms. I have used CBD in a continuous flow microreactor to deposit ZnO nanowire arrays and CdZnS films whose optoelectronic properties vary as a function of position. The spatially-dependent optoelectronic properties of these materials have been correlated to changes in the composition, structure or growth mechanisms of the materials and ultimately their growth conditions by rigorous spatial characterization. CBD in a continuous flow microreactor, coupled with spatial characterization, provides a new route to understanding the connection between CBD growth conditions and the resulting optoelectronic properties of the film. The high surface-to-volume ratio of a microreactor also lends itself to in situ characterization studies. I demonstrated the first in situ x-ray absorption fine-structure spectroscopy (XAFS) study of CBD. The high sensitivity and ability to characterize liquid, amorphous and crystalline materials simultaneously make in situ XAFS spectroscopy an ideal tool to study the CBD of inorganic nanomaterials.

Varietal discrimination of hop pellets by near and mid infrared spectroscopy.

PubMed

Machado, Julio C; Faria, Miguel A; Ferreira, Isabel M P L V O; Páscoa, Ricardo N M J; Lopes, João A

2018-04-01

Hop is one of the most important ingredients of beer production and several varieties are commercialized. Therefore, it is important to find an eco-real-time-friendly-low-cost technique to distinguish and discriminate hop varieties. This paper describes the development of a method based on vibrational spectroscopy techniques, namely near- and mid-infrared spectroscopy, for the discrimination of 33 commercial hop varieties. A total of 165 samples (five for each hop variety) were analysed by both techniques. Principal component analysis, hierarchical cluster analysis and partial least squares discrimination analysis were the chemometric tools used to discriminate positively the hop varieties. After optimizing the spectral regions and pre-processing methods a total of 94.2% and 96.6% correct hop varieties discrimination were obtained for near- and mid-infrared spectroscopy, respectively. The results obtained demonstrate the suitability of these vibrational spectroscopy techniques to discriminate different hop varieties and consequently their potential to be used as an authenticity tool. Compared with the reference procedures normally used for hops variety discrimination these techniques are quicker, cost-effective, non-destructive and eco-friendly. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative Analysis of Microbicide Concentrations in Fluids, Gels and Tissues Using Confocal Raman Spectroscopy

PubMed Central

Chuchuen, Oranat; Henderson, Marcus H.; Sykes, Craig; Kim, Min Sung; Kashuba, Angela D. M.; Katz, David F.

2013-01-01

Topical vaginal anti-HIV microbicides are an important focus in female-based strategies to prevent the sexual transmission of HIV. Understanding microbicide pharmacokinetics is essential to development, characterization and implementation of efficacious microbicide drug delivery formulations. Current methods to measure drug concentrations in tissue (e.g., LC-MS/MS, liquid chromatography coupled with tandem mass spectrometry) are highly sensitive, but destructive and complex. This project explored the use of confocal Raman spectroscopy to detect microbicide drugs and to measure their local concentrations in fluids, drug delivery gels, and tissues. We evaluated three candidate microbicide drugs: tenofovir, Dapivirine and IQP-0528. Measurements were performed in freshly excised porcine buccal tissue specimens, gel vehicles and fluids using two Horiba Raman microscopes, one of which is confocal. Characteristic spectral peak calibrations for each drug were obtained using serial dilutions in the three matrices. These specific Raman bands demonstrated strong linear concentration dependences in the matrices and were characterized with respect to their unique vibrational signatures. At least one specific Raman feature was identified for each drug as a marker band for detection in tissue. Sensitivity of detection was evaluated in the three matrices. A specific peak was also identified for tenofovir diphosphate, the anti-HIV bioactive product of tenofovir after phosphorylation in host cells. Z-scans of drug concentrations vs. depth in excised tissue specimens, incubated under layers of tenofovir solution in a Transwell assay, showed decreasing concentration with depth from the surface into the tissue. Time-dependent concentration profiles were obtained from tissue samples incubated in the Transwell assay, for times ranging 30 minutes - 6 hours. Calibrations and measurements from tissue permeation studies for tenofovir showed good correlation with gold standard LC-MS/MS data. These results demonstrate that confocal Raman spectroscopy holds promise as a tool for practical, minimally invasive, label-free measurement of microbicide drug concentrations in fluids, gels and tissues. PMID:24386455

Recent advances in the use of NIR spectroscopy for qualitative control and protection of extra virgin olive oil

USDA-ARS?s Scientific Manuscript database

Recent studies on the use of near infrared (NIR) spectroscopy for the qualitative characterization of extra virgin olive oil, are reported and discussed in this paper. Research results confirms that NIR spectroscopy, combined with chemometric data analysis, allows to simultaneously evaluate all qual...

Preparation, characterization and thermolysis of phenylenediammonium dinitrate salts.

PubMed

Kapoor, Inder Pal Singh; Srivastava, Pratibha; Singh, Gurdip

2008-02-11

Four phenylenediammonium dinitrate salts were prepared and characterized by elemental, Infrared spectroscopy (IR), Ultraviolet spectroscopy (UV) and gravimetric methods. These dinitrates find application in propellant, explosives and pyrotechnics. Their thermal decomposition has been studied using thermogravimetry (TG) and simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC). Kinetics parameters were evaluated by model fitting and isoconversional methods. Their thermolytic pathways have also been suggested, which involves decomposition followed by ignition.

Synthesis and characterization of a new Inonotus obliquus polysaccharide-iron(III) complex.

PubMed

Wang, Jia; Chen, Haixia; Wang, Yanwei; Xing, Lisha

2015-04-01

A new Inonotus obliquus polysaccharide-iron(III) complex (IOPS-iron) was synthesized and characterized. The preparation conditions of IOPS-iron(III) were optimized and the physicochemical properties were characterized by physicochemical methods, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, respectively. The highest iron content of IOPS-iron(III) complex (19.40%) was obtained at the conditions: the ratio of IOPS and FeCl3 • 6H2O was 3:5 (w/w), the pH value of alkali solution was 10, the reaction temperature was 30 °C and the reaction time was 6h. The iron(III) was shown to be bound through the binding sites of the polysaccharide IOPS and it could form spatially separated iron centers on the polysaccharide backbone. IOPS-iron(III) complex was found to have good digestive availability and antioxidant activities in the in vitro assays, which suggested the IOPS-iron(III) complex might be used as a new iron supplement candidate. Copyright © 2015 Elsevier B.V. All rights reserved.

Structural characterization of chemical warfare agent degradation products in decontamination solutions with proton band-selective (1)H-(31)P NMR spectroscopy.

PubMed

Koskela, Harri; Hakala, Ullastiina; Vanninen, Paula

2010-06-15

Decontamination solutions, which are usually composed of strong alkaline chemicals, are used for efficient detoxification of chemical warfare agents (CWAs). The analysis of CWA degradation products directly in decontamination solutions is challenging due to the nature of the matrix. Furthermore, occasionally an unforeseen degradation pathway can result in degradation products which could be eluded to in standard analyses. Here, we present the results of the application of proton band-selective (1)H-(31)P NMR spectroscopy, i.e., band-selective 1D (1)H-(31)P heteronuclear single quantum coherence (HSQC) and band-selective 2D (1)H-(31)P HSQC-total correlation spectroscopy (TOCSY), for ester side chain characterization of organophosphorus nerve agent degradation products in decontamination solutions. The viability of the approach is demonstrated with a test mixture of typical degradation products of nerve agents sarin, soman, and VX. The proton band-selective (1)H-(31)P NMR spectroscopy is also applied in characterization of unusual degradation products of VX in GDS 2000 solution.

Breast tumor characterization using near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Kang, Kyung A.; Chance, Britton; Zhao, Shiyin; Srinivasan, Sudhakar; Patterson, E.; Troupin, R.

1993-09-01

NIR time resolved spectroscopy (TRS) is one of the most feasible methods which can be used for the characterization of biological systems, due to its non-invasive nature and safety features in measurement. Breast cancer is the leading cause of death in women ages 40 - 44 and accounts for 32% of all cancer diagnosis in women. The occurrence rate is as high as one out of nine women in the USA. Breast cancer is the most common form of cancer and the second leading cause of cancer death in North America. Therefore, it is natural for researchers in the field of NIR spectroscopy to have strong interest in optical properties of normal and abnormal breast tissue. One of the main interests of NIR spectroscopy in breast cancer is the localization of the tumor. Another important feature is to characterize an anomaly non- invasively since more than 75% of mammographical anomalies are found to be benign. This could reduce the anxiety that the patients would have, as well as lower the clinical expense for the biopsy and operation (approximately $4,000 per a case).

Spectroscopic sensitivity of real-time, rapidly induced phytochemical change in response to damage.

PubMed

Couture, John J; Serbin, Shawn P; Townsend, Philip A

2013-04-01

An ecological consequence of plant-herbivore interactions is the phytochemical induction of defenses in response to insect damage. Here, we used reflectance spectroscopy to characterize the foliar induction profile of cardenolides in Asclepias syriaca in response to damage, tracked in vivo changes and examined the influence of multiple plant traits on cardenolide concentrations. Foliar cardenolide concentrations were measured at specific time points following damage to capture their induction profile. Partial least-squares regression (PLSR) modeling was employed to calibrate cardenolide concentrations to reflectance spectroscopy. In addition, subsets of plants were either repeatedly sampled to track in vivo changes or modified to reduce latex flow to damaged areas. Cardenolide concentrations and the induction profile of A. syriaca were well predicted using models derived from reflectance spectroscopy, and this held true for repeatedly sampled plants. Correlations between cardenolides and other foliar-related variables were weak or not significant. Plant modification for latex reduction inhibited an induced cardenolide response. Our findings show that reflectance spectroscopy can characterize rapid phytochemical changes in vivo. We used reflectance spectroscopy to identify the mechanisms behind the production of plant secondary metabolites, simultaneously characterizing multiple foliar constituents. In this case, cardenolide induction appears to be largely driven by enhanced latex delivery to leaves following damage. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Quantum state resolved velocity-map imaging spectroscopy: a new tool for collision dynamics at gas/self-assembled monolayer interfaces.

PubMed

Roscioli, Joseph R; Nesbitt, David J

2011-01-01

The dynamics of HCI scattering from a room-temperature -CH3 terminated self-assembled monolayer (SAM) is probed via state-resolved spectroscopy coupled to a velocity-map imaging (VMI) apparatus. The resulting velocity maps provide new insight into the HCl scattering trajectories, revealing for the first time correlations between internal and translational degrees of freedom. Velocity maps at low J are dominated by signatures of both the incident beam (17.3(3) kcal mol(-1)) and a room-temperature trapping-desorption component (TD). At high J, however, the maps contain a large, continuous feature associated primarily with impulsive scattering (IS). Trajectories resulting from these strongly inelastic interactions are readily isolated in the map, and provide a new glimpse into purely impulsive scattering dynamics. Specifically, within the purely-IS HCI region of the velocity maps, the rotational distribution is found to be remarkably Boltzmann like, but with a temperature (472 K) significantly higher than the SAM surface (300 K). By way of contrast, the translational degree of freedom of the impulsively-scattered flux is clearly non-Boltzmann in character, with a strong propensity for in-plane scattering in the forward direction, and yet still exhibiting out-of-plane velocity distributions reasonably well characterized by a temperature of 690 K. These first data establish the prospects for a new class of experimental tools aimed at exploring energy transfer and reactive scattering events on SAMs, liquid, and metal interfaces with quantum state resolved information on correlated internal and translational distributions.

Combination of magnetic resonance imaging and diffuse optical spectroscopy to predict radiation response in the breast: an exploratory pilot study

NASA Astrophysics Data System (ADS)

Klifa, C.; Hattangadi, J.; Watkins, M.; Li, A.; Sakata, T.; Tromberg, B.; Hylton, N.; Park, C.

2007-02-01

Radiation therapy (RT) is a standard treatment after lumpectomy for breast cancer, involving a typical course of approximately 6-7 weeks of daily treatment. Many women find this cumbersome and costly, and therefore many are left with the option of mastectomy. Many groups are now investigating novel ways to deliver RT, by using different techniques and shortening the course of treatment. However, the efficacy and side effects of these strategies are not known. In this project, we wish to develop noninvasive imaging tools that would allow us to measure radiation dose effects in women with breast cancer. We hope this will lead to new ways to identify individuals who may not need radiation therapy, who may safely be treated with new accelerated techniques, or who should be treated with the standard radiation therapy approach. We propose to study the effect of radiation therapy using a combination of two imaging modalities: 1) magnetic resonance imaging (MRI) which will provide detailed information on breast structures and blood vessels and 2) near infra-red diffuse optical spectroscopy (DOS), which measures local biologic properties of breast tissue. Our hypothesis is that by using a combination of modalities we will be able to better characterize radiation effects in breast tissue, by measuring differences between the radiated and non-irradiated breast. The development of novel non-invasive tools providing information about how individuals respond to radiation therapy can lead to important improvement of radiation treatment, and ultimately help guide individualized treatment programs in the future.

Endoscopy-coupled Raman spectroscopy for in vivo discrimination of inflammatory bowel disease

NASA Astrophysics Data System (ADS)

Pence, I. J.; Nguyen, Q. T.; Bi, X.; Herline, A. J.; Beaulieu, D. M.; Horst, S. N.; Schwartz, D. A.; Mahadevan-Jansen, A.

2014-03-01

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's colitis (CC), affects nearly 2 million Americans, and the incidence is increasing worldwide. It has been established that UC and CC are distinct forms of IBD and require different medical care, however the distinction made between UC and CC is based upon inexact clinical, radiological, endoscopic, and pathologic features. A diagnosis of indeterminate colitis occurs in up to 15% of patients when UC and CC features overlap and cannot be differentiated; in these patients, diagnosis relies on long term followup, success or failure of existing treatment, and recurrence of the disease. Thus, there is need for a tool that can improve the sensitivity and specificity for fast, accurate and automated diagnosis of IBD. Here we present colonoscopy-coupled fiber probe-based Raman spectroscopy as a novel in vivo diagnostic tool for IBD. This in vivo study of both healthy control (NC, N=10) and diagnosed IBD patients with UC (N=15) and CC (N=26) aims to characterize spectral signatures of NC, UC, and CC. Samples are correlated with tissue pathology markers and endoscopic evaluation. Optimal collection parameters for detection have been identified based upon the new, application specific instrument design. The collected spectra are processed and analyzed using multivariate statistical techniques to identify spectral markers and discriminate NC, UC, and CC. Development of spectral markers to discriminate disease type is a necessary first step in the development of real-time, accurate and automated in vivo detection of IBD during colonoscopy procedures.

In line NIR quantification of film thickness on pharmaceutical pellets during a fluid bed coating process.

PubMed

Lee, Min-Jeong; Seo, Da-Young; Lee, Hea-Eun; Wang, In-Chun; Kim, Woo-Sik; Jeong, Myung-Yung; Choi, Guang J

2011-01-17

Along with the risk-based approach, process analytical technology (PAT) has emerged as one of the key elements to fully implement QbD (quality-by-design). Near-infrared (NIR) spectroscopy has been extensively applied as an in-line/on-line analytical tool in biomedical and chemical industries. In this study, the film thickness on pharmaceutical pellets was examined for quantification using in-line NIR spectroscopy during a fluid-bed coating process. A precise monitoring of coating thickness and its prediction with a suitable control strategy is crucial to the quality assurance of solid dosage forms including dissolution characteristics. Pellets of a test formulation were manufactured and coated in a fluid-bed by spraying a hydroxypropyl methylcellulose (HPMC) coating solution. NIR spectra were acquired via a fiber-optic probe during the coating process, followed by multivariate analysis utilizing partial least squares (PLS) calibration models. The actual coating thickness of pellets was measured by two separate methods, confocal laser scanning microscopy (CLSM) and laser diffraction particle size analysis (LD-PSA). Both characterization methods gave superb correlation results, and all determination coefficient (R(2)) values exceeded 0.995. In addition, a prediction coating experiment for 70min demonstrated that the end-point can be accurately designated via NIR in-line monitoring with appropriate calibration models. In conclusion, our approach combining in-line NIR monitoring with CLSM and LD-PSA can be applied as an effective PAT tool for fluid-bed pellet coating processes. Copyright © 2010 Elsevier B.V. All rights reserved.

Fluorescence spectroscopy for the detection of potentially malignant disorders and squamous cell carcinoma of the oral cavity.

PubMed

Francisco, Ana Lucia Noronha; Correr, Wagner Rafael; Azevedo, Luciane Hiramatsu; Kern, Vivian Galletta; Pinto, Clóvis Antônio Lopes; Kowalski, Luiz Paulo; Kurachi, Cristina

2014-06-01

Oral cancer is a public health problem with relevant incidence in the world population. The affected patient usually presents advanced stage disease and the consequence of this delay is a reduction in survival rates. Given this, it is essential to detect oral cancer at early stages. Fluorescence spectroscopy is a non-invasive diagnostic tool that can improve cancer detection in real time. It is a fast and accurate technique, relatively simple, which evaluates the biochemical composition and structure using the tissue fluorescence spectrum as interrogation data. Several studies have positive data regarding the tools for differentiating between normal mucosa and cancer, but the difference between cancer and potentially malignant disorders is not clear. The aim of this study was to evaluate the efficacy of fluorescence spectroscopy in the discrimination of normal oral mucosa, oral cancer, and potentially malignant disorders. The fluorescence spectroscopy was evaluated in 115 individuals, of whom 55 patients presented oral squamous cell carcinoma, 30 volunteers showing normal oral mucosa, and 30 patients having potentially malignant disorders. The spectra were classified and compared to histopathology to evaluate the efficiency in diagnostic discrimination employing fluorescence. In order to classify the spectra, a decision tree algorithm (C4.5) was applied. Despite of the high variance observed in spectral data, the specificity and sensitivity obtained were 93.8% and 88.5%, respectively at 406 nm excitation. These results point to the potential use of fluorescence spectroscopy as an important tool for oral cancer diagnosis and potentially malignant disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

FT-Raman Spectroscopy: A Catalyst for the Raman Explosion?

ERIC Educational Resources Information Center

Chase, Bruce

2007-01-01

The limitations of Fourier transform (FT) Raman spectroscopy, which is used to detect and analyze the scattered radiation, are discussed. FT-Raman has served to revitalize a field that was lagging and the presence of Raman instrumentation as a routine analytical tool is established for the foreseeable future.

NANOSTRUCTURED PLANAR WAVEGUIDE DEVICE FOR MOLECULAR IDENTIFICATION OF HAZARDOUS COMPOUNDS IN WATER BY EVANESCENT SURFACE ENHANCED RAMAN SPECTROSCOPY - PHASE I

EPA Science Inventory

Senspex, Inc. proposes to investigate a novel diagnostic tool based upon evanescent field planar waveguide sensing and complementary nanostructured mediated molecular vibration spectroscopy methods for rapid detection and analysis of hazardous biological and chemical targets i...

Visible/near-infrared spectroscopy to predict water holding capacity in broiler breast meat

USDA-ARS?s Scientific Manuscript database

Visible/Near-infrared spectroscopy (Vis/NIRS) was examined as a tool for rapidly determining water holding capacity (WHC) in broiler breast meat. Both partial least squares (PLS) and principal component analysis (PCA) models were developed to relate Vis/NIRS spectra of 85 broiler breast meat sample...

Improved molecular fingerprint analysis employing multi-branched gold nanoparticles in conjunction with surface-enhanced Raman scattering.

PubMed

Johnston, Jencilin; Taylor, Erik N; Gilbert, Richard J; Webster, Thomas J

2016-01-01

Vibrational spectroscopy is a powerful analytical tool that assesses molecular properties based on spectroscopic signatures. In this study, the effect of gold nanoparticle morphology (spherical vs multi-branched) was assessed for the characterization of a Raman signal (ie, molecular fingerprint) that may be helpful for numerous medical applications. Multi-branched gold nanoparticles (MBAuNPs) were fabricated using a green chemistry method which employed the reduction of gold ion solute by 2-[4-(2-hydroxyethyl)-1-piperazyl] ethane sulfonic acid. Two types of reporter dyes, indocyanine (IR820 and IR792) and carbocyanine (DTTC [3,3'-diethylthiatricarbocyanine iodide] and DTDC [3,3'-diethylthiadicarbocyanine iodide]), were functionalized to the surface of the MBAuNPs and stabilized with denatured bovine serum albumin, thus forming the surface-enhanced Raman spectroscopy tag. Fluorescein isothiocyanate-conjugated anti-epidermal growth factor receptor to the surface-enhanced Raman spectroscopy tags and the properties of the resulting conjugates were assessed through determination of the Raman signal. Using the MBAuNP Raman probes synthesized in this manner, we demonstrated that MBAuNP provided significantly more surface-enhanced Raman scattering signal when compared with the associated spherical gold nanoparticle of similar size and concentration. MBAuNP enhancements were retained in the surface-enhanced Raman spectroscopy tags complexed to anti-epidermal growth factor receptor, providing evidence that this could be a useful biological probe for enhanced Raman molecular fingerprinting. Furthermore, while utilizing IR820 as a novel reporter dye linked with MBAuNP, superior Raman signal fingerprint results were obtained. Such results provide significant promise for the use of MBAuNP in the detection of numerous diseases for which biologically specific surface markers exist.

Biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis

NASA Astrophysics Data System (ADS)

Neto, Lázaro P. M.; Martin, Aírton A.; Soto, Claudio A. T.; Santos, André B. O.; Mello, Evandro S.; Pereira, Marina A.; Cernea, Cláudio R.; Brandão, Lenine G.; Canevari, Renata A.

2016-02-01

Thyroid carcinomas represent the main endocrine malignancy and their diagnosis may produce inconclusive results. Raman spectroscopy and gene expression analysis have shown excellent results on the differentiation of carcinomas. This study aimed to improve the discrimination between different thyroid pathologies combining of both analyses. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. Confocal Raman spectra was obtain by using a Rivers Diagnostic System, 785 nm laser excitation and CCD detector. The data was processed by the software Labspec5 and Origin 8.5 and analyzed by Minitab® program. The gene expression analysis was performed by qRT-PCR technique for TG, TPO, PDGFB, SERPINA1, LGALS3 and TFF3 genes and statistically analyzed by Mann-Whitney test. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. Significant differences was observed for TG, LGALS3, SERPINA1 and TFF3 genes between benign lesions and carcinomas, and SERPINA1 and TFF3 genes between papillary and follicular carcinomas. Principal component analysis was performed using PC1 and PC2 in the papillary carcinoma samples that showed over gene expression when compared with normal sample, where 90% of discrimination was observed at the Amide 1 (1655 cm-1), and at the tyrosine spectra region (856 cm-1). The discrimination of tissues thyroid carried out by confocal Raman spectroscopy and gene expression analysis indicate that these techniques are promising tools to be used in the diagnosis of thyroid lesions.

Investigation of the Sensitivity of Transmission Raman Spectroscopy for Polymorph Detection in Pharmaceutical Tablets.

PubMed

Feng, Hanzhou; Bondi, Robert W; Anderson, Carl A; Drennen, James K; Igne, Benoît

2017-08-01

Polymorph detection is critical for ensuring pharmaceutical product quality in drug substances exhibiting polymorphism. Conventional analytical techniques such as X-ray powder diffraction and solid-state nuclear magnetic resonance are utilized primarily for characterizing the presence and identity of specific polymorphs in a sample. These techniques have encountered challenges in analyzing the constitution of polymorphs in the presence of other components commonly found in pharmaceutical dosage forms. Laborious sample preparation procedures are usually required to achieve satisfactory data interpretability. There is a need for alternative techniques capable of probing pharmaceutical dosage forms rapidly and nondestructively, which is dictated by the practical requirements of applications such as quality monitoring on production lines or when quantifying product shelf lifetime. The sensitivity of transmission Raman spectroscopy for detecting polymorphs in final tablet cores was investigated in this work. Carbamazepine was chosen as a model drug, polymorph form III is the commercial form, whereas form I is an undesired polymorph that requires effective detection. The concentration of form I in a direct compression tablet formulation containing 20% w/w of carbamazepine, 74.00% w/w of fillers (mannitol and microcrystalline cellulose), and 6% w/w of croscarmellose sodium, silicon dioxide, and magnesium stearate was estimated using transmission Raman spectroscopy. Quantitative models were generated and optimized using multivariate regression and data preprocessing. Prediction uncertainty was estimated for each validation sample by accounting for all the main variables contributing to the prediction. Multivariate detection limits were calculated based on statistical hypothesis testing. The transmission Raman spectroscopic model had an absolute prediction error of 0.241% w/w for the independent validation set. The method detection limit was estimated at 1.31% w/w. The results demonstrated that transmission Raman spectroscopy is a sensitive tool for polymorphs detection in pharmaceutical tablets.

Raman spectroscopy of graphene-based materials and its applications in related devices.

PubMed

Wu, Jiang-Bin; Lin, Miao-Ling; Cong, Xin; Liu, He-Nan; Tan, Ping-Heng

2018-03-05

Graphene-based materials exhibit remarkable electronic, optical, and mechanical properties, which has resulted in both high scientific interest and huge potential for a variety of applications. Furthermore, the family of graphene-based materials is growing because of developments in preparation methods. Raman spectroscopy is a versatile tool to identify and characterize the chemical and physical properties of these materials, both at the laboratory and mass-production scale. This technique is so important that most of the papers published concerning these materials contain at least one Raman spectrum. Thus, here, we systematically review the developments in Raman spectroscopy of graphene-based materials from both fundamental research and practical (i.e., device applications) perspectives. We describe the essential Raman scattering processes of the entire first- and second-order modes in intrinsic graphene. Furthermore, the shear, layer-breathing, G and 2D modes of multilayer graphene with different stacking orders are discussed. Techniques to determine the number of graphene layers, to probe resonance Raman spectra of monolayer and multilayer graphenes and to obtain Raman images of graphene-based materials are also presented. The extensive capabilities of Raman spectroscopy for the investigation of the fundamental properties of graphene under external perturbations are described, which have also been extended to other graphene-based materials, such as graphene quantum dots, carbon dots, graphene oxide, nanoribbons, chemical vapor deposition-grown and SiC epitaxially grown graphene flakes, composites, and graphene-based van der Waals heterostructures. These fundamental properties have been used to probe the states, effects, and mechanisms of graphene materials present in the related heterostructures and devices. We hope that this review will be beneficial in all the aspects of graphene investigations, from basic research to material synthesis and device applications.

Differential laser-induced perturbation spectroscopy and fluorescence imaging for biological and materials sensing

NASA Astrophysics Data System (ADS)

Burton, Dallas Jonathan

The field of laser-based diagnostics has been a topic of research in various fields, more specifically for applications in environmental studies, military defense technologies, and medicine, among many others. In this dissertation, a novel laser-based optical diagnostic method, differential laser-induced perturbation spectroscopy (DLIPS), has been implemented in a spectroscopy mode and expanded into an imaging mode in combination with fluorescence techniques. The DLIPS method takes advantage of deep ultraviolet (UV) laser perturbation at sub-ablative energy fluences to photochemically cleave bonds and alter fluorescence signal response before and after perturbation. The resulting difference spectrum or differential image adds more information about the target specimen, and can be used in combination with traditional fluorescence techniques for detection of certain materials, characterization of many materials and biological specimen, and diagnosis of various human skin conditions. The differential aspect allows for mitigation of patient or sample variation, and has the potential to develop into a powerful, noninvasive optical sensing tool. The studies in this dissertation encompass efforts to continue the fundamental research on DLIPS including expansion of the method to an imaging mode. Five primary studies have been carried out and presented. These include the use of DLIPS in a spectroscopy mode for analysis of nitrogen-based explosives on various substrates, classification of Caribbean fruit flies versus Caribbean fruit flies that have been irradiated with gamma rays, and diagnosis of human skin cancer lesions. The nitrogen-based explosives and Caribbean fruit flies have been analyzed with the DLIPS scheme using the imaging modality, providing complementary information to the spectroscopic scheme. In each study, a comparison between absolute fluorescence signals and DLIPS responses showed that DLIPS statistically outperformed traditional fluorescence techniques with regards to regression error and classification.

Improved molecular fingerprint analysis employing multi-branched gold nanoparticles in conjunction with surface-enhanced Raman scattering

PubMed Central

Johnston, Jencilin; Taylor, Erik N; Gilbert, Richard J; Webster, Thomas J

2016-01-01

Vibrational spectroscopy is a powerful analytical tool that assesses molecular properties based on spectroscopic signatures. In this study, the effect of gold nanoparticle morphology (spherical vs multi-branched) was assessed for the characterization of a Raman signal (ie, molecular fingerprint) that may be helpful for numerous medical applications. Multi-branched gold nanoparticles (MBAuNPs) were fabricated using a green chemistry method which employed the reduction of gold ion solute by 2-[4-(2-hydroxyethyl)-1-piperazyl] ethane sulfonic acid. Two types of reporter dyes, indocyanine (IR820 and IR792) and carbocyanine (DTTC [3,3′-diethylthiatricarbocyanine iodide] and DTDC [3,3′-diethylthiadicarbocyanine iodide]), were functionalized to the surface of the MBAuNPs and stabilized with denatured bovine serum albumin, thus forming the surface-enhanced Raman spectroscopy tag. Fluorescein isothiocyanate-conjugated anti-epidermal growth factor receptor to the surface-enhanced Raman spectroscopy tags and the properties of the resulting conjugates were assessed through determination of the Raman signal. Using the MBAuNP Raman probes synthesized in this manner, we demonstrated that MBAuNP provided significantly more surface-enhanced Raman scattering signal when compared with the associated spherical gold nanoparticle of similar size and concentration. MBAuNP enhancements were retained in the surface-enhanced Raman spectroscopy tags complexed to anti-epidermal growth factor receptor, providing evidence that this could be a useful biological probe for enhanced Raman molecular fingerprinting. Furthermore, while utilizing IR820 as a novel reporter dye linked with MBAuNP, superior Raman signal fingerprint results were obtained. Such results provide significant promise for the use of MBAuNP in the detection of numerous diseases for which biologically specific surface markers exist. PMID:26730189

Spec Tool; an online education and research resource

NASA Astrophysics Data System (ADS)

Maman, S.; Shenfeld, A.; Isaacson, S.; Blumberg, D. G.

2016-06-01

Education and public outreach (EPO) activities related to remote sensing, space, planetary and geo-physics sciences have been developed widely in the Earth and Planetary Image Facility (EPIF) at Ben-Gurion University of the Negev, Israel. These programs aim to motivate the learning of geo-scientific and technologic disciplines. For over the past decade, the facility hosts research and outreach activities for researchers, local community, school pupils, students and educators. As software and data are neither available nor affordable, the EPIF Spec tool was created as a web-based resource to assist in initial spectral analysis as a need for researchers and students. The tool is used both in the academic courses and in the outreach education programs and enables a better understanding of the theoretical data of spectroscopy and Imaging Spectroscopy in a 'hands-on' activity. This tool is available online and provides spectra visualization tools and basic analysis algorithms including Spectral plotting, Spectral angle mapping and Linear Unmixing. The tool enables to visualize spectral signatures from the USGS spectral library and additional spectra collected in the EPIF such as of dunes in southern Israel and from Turkmenistan. For researchers and educators, the tool allows loading collected samples locally for further analysis.

HIDRA-MAT: A Material Analysis Tool for Fusion Devices

NASA Astrophysics Data System (ADS)

Andruczyk, Daniel; Rizkallah, Rabel; Bedoya, Felipe; Kapat, Aveek; Schamis, Hanna; Allain, Jean Paul

2017-10-01

The former WEGA stellarator which is now operating as HIDRA at the University of Illinois will be almost exclusively used to study the intimate relationship between the plasma interacting with surfaces of different materials. A Material Analysis Tool (HIDRA-MAT) is being designed and will be built based on the successful Material Analysis and Particle Probe (MAPP) which is currently used on NSTX-U at PPPL. This will be an in-situ material diagnostic probe, meaning that all analysis can be done without breaking vacuum. This allows surface changes to be studied in real-time. HIDRA-MAT will consist of several in-situ diagnostics including Langmuir probes (LP), Thermal Desorption Spectroscopy (TDS), X-ray Photo Spectroscopy (XPS) and Ion Scattering Spectroscopy (ISS). This presentation will outline the HIDRA-MAT diagnostic and initial design, as well as its integration into the HIDRA system.

Metal-dielectric interactions

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1979-01-01

Metal direlectric surface interactions and dielectric films on metal substrates were investigated. Since interfacial interaction depends so heavily on the nature of the surfaces, analytical surface tools such as Auger emission spectroscopy, X-ray photoelectron spectroscopy and field ion microscopy were used to assist in surface and interfacial characterization. The results indicate that with metals contacting certain glasses in the clean state interfacial, bonding produces fractures in the glasses while when a film such as water is present, fractures occur in the metal near the interface. Friction forces were used to measure the interfacial bond strengths. Studies with metals contacting polymers using field ion microscopy revealed that strong bonding forces could develop being between a metal and polymer surface with polymer transferring to the metal surface in various ways depending upon the forces applied to the surface in contact. With the deposition of refractory carbides, silicides and borides onto metal and alloy substrates the presence of oxides at the interface or active gases in the deposition plasma were shown to alter interfacial properties and chemistry. Auger ion depth profile analysis indicated the chemical composition at the interface and this could be related to the mechanical, friction, and wear behavior of the coating.

Understanding THz spectra of aqueous solutions: glycine in light and heavy water.

PubMed

Sun, Jian; Niehues, Gudrun; Forbert, Harald; Decka, Dominique; Schwaab, Gerhard; Marx, Dominik; Havenith, Martina

2014-04-02

THz spectroscopy of aqueous solutions has been established as of recently to be a valuable and complementary experimental tool to provide direct insights into the solute-solvent coupling due to hydrogen-bond dynamics involving interfacial water. Despite much experimental progress, understanding THz spectra in terms of molecular motions, akin to mid-infrared spectra, still remains elusive. Here, using the osmoprotectant glycine as a showcase, we demonstrate how this can be achieved by combining THz absorption spectroscopy and ab initio molecular dynamics. The experimental THz spectrum is characterized by broad yet clearly discernible peaks. Based on substantial extensions of available mode-specific decomposition schemes, the experimental spectrum can be reproduced by theory and assigned on an essentially quantitative level. This joint effort reveals an unexpectedly clear picture of the individual contributions of molecular motion to the THz absorption spectrum in terms of distinct modes stemming from intramolecular vibrations, rigid-body-like hindered rotational and translational motion, and specific couplings to interfacial water molecules. The assignment is confirmed by the peak shifts observed in the THz spectrum of deuterated glycine in heavy water, which allow us to separate the distinct modes experimentally.

Diagnostics of AC excited Atmospheric Pressure Plasma Jet with He for Biomedical Applications

NASA Astrophysics Data System (ADS)

Hori, Masaru; Takeda, Keigo; Kumakura, Takumi; Ishikawa, Kenji; Tanaka, Hiromasa; Kondo, Hiroki; Sekine, Makoto; Nakai, Yoshihiro

2014-10-01

Atmospheric pressure plasma jets (APPJ) are frequently used for biomedical applications. Reactive species generated by the APPJ play important roles for treatments of biomedical samples. Therefore, high density APPJ sources are required to realize the high performance. Our group has developed AC excited Ar APPJ with electron density as high as 1015 cm-3, and realized the selective killing of cancer cells and the inactivate spores of Penicillium digitatum. Recently, a new spot-size AC excited APPJ with He gas have been developed. In this study, the He APPJ was characterized by using spectroscopy. The plasma was discharged at a He flow rate of 5 slm and a discharge voltage of AC 9 kV. Gas temperature and electron density of the APPJ were measured by optical emission spectroscopy. From theoretical fitting of 2nd positive system of N2 emission (380.4 nm) and Stark broadening of Balmer β line of H atom (486.1 nm), the gas temperature and the electron density was estimated to be 299 K and 3.4. × 1015 cm-3. The AC excited He APPJ has a potential to realize high density with room temperature and become a very powerful tool for biomedical applications.

Probing Active Species in the Nanoscale by Combining XAFS and TEM in Operando Conditions

NASA Astrophysics Data System (ADS)

Frenkel, Anatoly

Understanding mechanisms of work in nanoscale systems is often hindered by their inherent complexity and by our inability to identify and characterize their ``active'' sites. In the size range of 1-5nm, they feature a variety of structural motifs, sizes, shapes, compositions, degrees of crystalline order as well as multiple temporal scales. An additional challenge is that only a fraction of them are actors in the catalytic performance, while majority are spectators. Significant progress in developing such tools for studying nanomaterials can be achieved only when active species can be reliably isolated from spectators, and their role in mechanism of work is understood. In our approach the activity of nanomaterial is measured concurrently with other characteristics, obtained by advanced scattering, spectroscopy and imaging methods. In this talk I will demonstrate the application of a microreactor, compatible with electron microscopy and X-ray Absorption Fine Structure spectroscopy probes, for this purpose. I will illustrate its application by our observation of reaction-driven restructuring of Pt catalysts in the size range from single atoms to 3nm in diameter during catalytic hydrogenation of ethylene. We acknowledge support of DOE BES Grant No. DE-FG02- 03ER15476.

Investigation of polydopamine coatings by X-ray Photoelectron Spectroscopy as an effective tool for improving biomolecule conjugation

NASA Astrophysics Data System (ADS)

Rella, Simona; Mazzotta, Elisabetta; Caroli, Antonio; De Luca, Maria; Bucci, Cecilia; Malitesta, Cosimino

2018-07-01

Polydopamine (PDA) films have attracted a rapidly increasing research attention during the last years due to its simple and rapid deposition under alkaline conditions in substrate independent manner providing a universal coating for materials with different chemical and physical properties. Furthermore, this polymerized layer is enriched with functional groups that enable immobilization of primary amine or thiol-based biomolecules via a simple dipping process. Although these aspects justify PDA wide and successful application as a versatile coating for biomolecule immobilization, several aspects have not been deeply investigated leaving some key details unclear and thus limiting PDA practical applications. A number of approaches are commonly used for the growth of PDA, but the effect of deposition conditions on film properties, which in turn influence biomolecule immobilization has not been systematically investigated yet. In the present work, an extensive characterization by X-ray Photoelectron Spectroscopy (XPS) is performed on PDA coatings grown under different experimental conditions. Comparison of XPS data about elemental composition, distribution of functional groups and thickness of PDA coatings provided valuable information for identifying more suitable PDA coating for biomolecule anchoring, further explored by in vitro experiments.

Polarized Raman Spectroscopy for Determining the Orientation of di-D-phenylalanine Molecules in a Nanotube.

PubMed

Sereda, Valentin; Ralbovsky, Nicole M; Vasudev, Milana C; Naik, Rajesh R; Lednev, Igor K

2016-09-01

Self-assembly of short peptides into nanostructures has become an important strategy for the bottom-up fabrication of nanomaterials. Significant interest to such peptide-based building blocks is due to the opportunity to control the structure and properties of well-structured nanotubes, nanofibrils, and hydrogels. X-ray crystallography and solution NMR, two major tools of structural biology, have significant limitations when applied to peptide nanotubes because of their non-crystalline structure and large weight. Polarized Raman spectroscopy was utilized for structural characterization of well-aligned D-Diphenylalanine nanotubes. The orientation of selected chemical groups relative to the main axis of the nanotube was determined. Specifically, the C-N bond of CNH 3 + groups is oriented parallel to the nanotube axis, the peptides' carbonyl groups are tilted at approximately 54° from the axis and the COO - groups run perpendicular to the axis. The determined orientation of chemical groups allowed the understanding of the orientation of D-diphenylalanine molecule that is consistent with its equilibrium conformation. The obtained data indicate that there is only one orientation of D-diphenylalanine molecules with respect to the nanotube main axis.

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

PubMed

Shaban, Mohamed; Galaly, A R

2016-05-04

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

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

PubMed Central

Shaban, Mohamed; Galaly, A. R.

2016-01-01

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

Characterization of the excited states of a squaraine molecule with quadratic electroabsorption spectroscopy

NASA Astrophysics Data System (ADS)

Poga, C.; Brown, T. M.; Kuzyk, M. G.; Dirk, Carl W.

1995-04-01

We apply quadratic electroabsorption spectroscopy (QES) to thin-film solid solutions of squarylium dye molecules in poly(methyl methacrylate) polymer to study the dye's electronic excited states and to investigate the importance of these states with regard to their contribution to the third-order nonlinear-optical susceptibility. We first show that the room-temperature tensor ratio a= chi (3)3333/ chi (3)1133 \\approximately 3 throughout most of the visible region to establish that the electronic mechanism dominates. Because QES is a third-order nonlinear-optical susceptibility measurement, it can be used to identify two photon states. By obtaining good agreement between the quadratic electroabsorption spectrum and a three level model, we conclude that there are two dominant states that contribute to the near-resonant and a two-photon state that are separated by less than 0.2 eV in energy. QES is thus shown to be a versatile tool for measuring the nature of excited states in a molecule. Furthermore, by applying a Kramers-Kronig transformation to determine the real part of the response, we are able to assess the two-photon all-optical device figure of merit of these materials. Such an

Evaluation of human serum of severe rheumatoid arthritis by confocal Raman spectroscopy

NASA Astrophysics Data System (ADS)

Carvalho, C. S.; Raniero, L.; Santo, A. M. E.; Pinheiro, M. M.; Andrade, L. E. C.; Cardoso, M. A. G.; Junior, J. S.; Martin, A. A.

2010-02-01

Rheumatoid Arthritis is a systemic chronic inflammatory disease, recurrent and systemic, initiated by autoantibodies and maintained by inflammatory mechanisms cellular applicants. The evaluation of this disease to promote early diagnosis, need an associations of many tools, such as clinical, physical examination and thorough medical history. However, there is no satisfactory consensus due to its complexity. In the present work, confocal Raman spectroscopy was used to evaluate the biochemical composition of human serum of 40 volunteers, 24 patients with rheumatoid arthritis presenting clinical signs and symptoms, and 16 healthy donors. The technique of latex agglutination for the polystyrene covered with human immunoglobulin G and PCR (protein c-reactive) was performed for confirmation of possible false-negative results within the groups, facilitating the statistical interpretation and validation of the technique. This study aimed to verify the changes for the characteristics Raman peaks of biomolecules such as immunoglobulins amides and protein. The results were highly significant with a good separation between groups mentioned. The discriminant analysis was performed through the principal components and correctly identified 92% of the donors. Based on these results, we observed the behavior of arthritis autoimmune, evident in certain spectral regions that characterize the serological differences between the groups.

Amplitude quantification in contact-resonance-based voltage-modulated force spectroscopy

NASA Astrophysics Data System (ADS)

Bradler, Stephan; Schirmeisen, André; Roling, Bernhard

2017-08-01

Voltage-modulated force spectroscopy techniques, such as electrochemical strain microscopy and piezoresponse force microscopy, are powerful tools for characterizing electromechanical properties on the nanoscale. In order to correctly interpret the results, it is important to quantify the sample motion and to distinguish it from the electrostatic excitation of the cantilever resonance. Here, we use a detailed model to describe the cantilever dynamics in contact resonance measurements, and we compare the results with experimental values. We show how to estimate model parameters from experimental values and explain how they influence the sensitivity of the cantilever with respect to the excitation. We explain the origin of different crosstalk effects and how to identify them. We further show that different contributions to the measured signal can be distinguished by analyzing the correlation between the resonance frequency and the measured amplitude. We demonstrate this technique on two representative test samples: (i) ferroelectric periodically poled lithium niobate, and (ii) the Na+-ion conducting soda-lime float glass. We extend our analysis to higher cantilever bending modes and show that non-local electrostatic excitation is strongly reduced in higher bending modes due to the nodes in the lever shape. Based on our analyses, we present practical guidelines for quantitative imaging.

Cyclen dithiocarbamate-functionalized silver nanoparticles as a probe for colorimetric sensing of thiram and paraquat pesticides via host-guest chemistry

NASA Astrophysics Data System (ADS)

Rohit, Jigneshkumar V.; Kailasa, Suresh Kumar

2014-11-01

We have developed a simple and rapid colorimetric method for on-site analysis of thiram and paraquat using cyclen dithiocarbamate-functionalized silver nanoparticles (CN-DTC-Ag NPs) as a colorimetric probe. The synthesized CN-DTC-Ag NPs were characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy, dynamic light scattering, and transmission electron microscopic techniques. The CN-DTC molecules provide good supramolecular self assembly on the surfaces of Ag NPs to encapsulate thiram and paraquat selectively via "host-guest" chemistry, resulting in red-shift in surface plasmon resonance peak of CN-DTC-Ag NPs from 396 to 530 nm and 510 nm and color change from yellow to pink for thiram and to orange for paraquat, which can be naked-eye detected. The present method shows good linearity in the range of 10.0-20.0 µM and of 50.0-250 µM with limits of detection 2.81 × 10-6 M and 7.21 × 10-6 M for thiram and paraquat, respectively. This method was proved as a promising tool for on-site and real-time monitoring of thiram and paraquat in environmental water, potato, and wheat samples.

Spectroscopic Studies of Pre-Biotic Carbon Chemistry

NASA Technical Reports Server (NTRS)

Blake, Geoffrey A.

2003-01-01

As described in the original proposal and in our progress reports, research in the Blake group supported by the Exobiology program seeks to understand the pre-biotic chemistry of carbon along with that of other first- and second-row elements from the earliest stages of star formation through the development of planetary systems. The major tool used is spectroscopy, and the program has observational, laboratory, and theoretical components. The observational and theoretical programs are concerned primarily with a quantitative assessment of the chemical budgets of the biogenic elements in the circumstellar environment of forming stars and planetary systems, while the laboratory work is focused on the complex species that characterize the pre-biotic chemistry of carbon. We outline below our results over the past year acquired, in part, with Exobiology support.

Linear and Nonlinear Molecular Spectroscopy with Laser Frequency Combs

NASA Astrophysics Data System (ADS)

Picque, Nathalie

2013-06-01

The regular pulse train of a mode-locked femtosecond laser can give rise to a comb spectrum of millions of laser modes with a spacing precisely equal to the pulse repetition frequency. Laser frequency combs were conceived a decade ago as tools for the precision spectroscopy of atomic hydrogen. They are now becoming enabling tools for an increasing number of applications, including molecular spectroscopy. Recent experiments of multi-heterodyne frequency comb Fourier transform spectroscopy (also called dual-comb spectroscopy) have demonstrated that the precisely spaced spectral lines of a laser frequency comb can be harnessed for new techniques of linear absorption spectroscopy. The first proof-of-principle experiments have demonstrated a very exciting potential of dual-comb spectroscopy without moving parts for ultra-rapid and ultra-sensitive recording of complex broad spectral bandwidth molecular spectra. Compared to conventional Michelson-based Fourier transform spectroscopy, recording times could be shortened from seconds to microseconds, with intriguing prospects for spectroscopy of short lived transient species. The resolution improves proportionally to the measurement time. Therefore longer recordings allow high resolution spectroscopy of molecules with extreme precision, since the absolute frequency of each laser comb line can be known with the accuracy of an atomic clock. Moreover, since laser frequency combs involve intense ultrashort laser pulses, nonlinear interactions can be harnessed. Broad spectral bandwidth ultra-rapid nonlinear molecular spectroscopy and imaging with two laser frequency combs is demonstrated with coherent Raman effects and two-photon excitation. Real-time multiplex accessing of hyperspectral images may dramatically expand the range of applications of nonlinear microscopy. B. Bernhardt et al., Nature Photonics 4, 55-57 (2010); A. Schliesser et al. Nature Photonics 6, 440-449 (2012); T. Ideguchi et al. arXiv:1201.4177 (2012) T. Ideguchi et al., Optics letters 37, 4498-4500 (2012); T. Ideguchi et al. arXiv:1302.2414 (2013)

High-power ultrafast Yb:fiber laser frequency combs using commercially available components and basic fiber tools

NASA Astrophysics Data System (ADS)

Li, Xinlong; Reber, Melanie A. R.; Corder, Christopher; Chen, Yuning; Zhao, Peng; Allison, Thomas K.

2016-09-01

We present a detailed description of the design, construction, and performance of high-power ultrafast Yb:fiber laser frequency combs in operation in our laboratory. We discuss two such laser systems: an 87 MHz, 9 W, 85 fs laser operating at 1060 nm and an 87 MHz, 80 W, 155 fs laser operating at 1035 nm. Both are constructed using low-cost, commercially available components, and can be assembled using only basic tools for cleaving and splicing single-mode fibers. We describe practical methods for achieving and characterizing low-noise single-pulse operation and long-term stability from Yb:fiber oscillators based on nonlinear polarization evolution. Stabilization of the combs using a variety of transducers, including a new method for tuning the carrier-envelope offset frequency, is discussed. High average power is achieved through chirped-pulse amplification in simple fiber amplifiers based on double-clad photonic crystal fibers. We describe the use of these combs in several applications, including ultrasensitive femtosecond time-resolved spectroscopy and cavity-enhanced high-order harmonic generation.

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

DOE PAGES

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; ...

2018-04-02

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less

Using time reversal to detect entanglement and spreading of quantum information

NASA Astrophysics Data System (ADS)

Gaerttner, Martin

2017-04-01

Characterizing and understanding the states of interacting quantum systems and their non-equilibrium dynamics is the goal of quantum simulation. For this it is crucial to find experimentally feasible means for quantifying how entanglement and correlation build up and spread. The ability of analog quantum simulators to reverse the unitary dynamics of quantum many-body systems provides new tools in this quest. One such tool is the multiple-quantum coherence (MQC) spectrum previously used in NMR spectroscopy which can now be studied in so far inaccessible parameter regimes near zero temperature in highly controllable environments. I present recent progress in relating the MQC spectrum to established entanglement witnesses such as quantum Fisher information. Recognizing the MQC as out-of-time-order correlation functions, which quantify the spreading, or scrambling, of quantum information, allows us to establish a connection between these quantities and multi-partite entanglement. I will show recent experimental results obtained with a trapped ion quantum simulator and a spinor BEC illustrating the power of time reversal protocols. Supported by: JILA-NSF-PFC-1125844, NSF-PHY-1521080, ARO, AFOSR, AFOSR-MURI, DARPA, NIST.

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

NASA Astrophysics Data System (ADS)

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; Zonno, M.; Peli, S.; Day, R. P.; Michiardi, M.; Schneider, M.; Zwartsenberg, B.; Nigge, P.; Zhong, R. D.; Schneeloch, J.; Gu, G. D.; Zhdanovich, S.; Mills, A. K.; Levy, G.; Jones, D. J.; Giannetti, C.; Damascelli, A.

2018-05-01

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces1,2, ultracold Fermi atoms3,4 and cuprate superconductors5,6, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. Here we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bi2Sr2CaCu2O8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

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

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less

Rubber.

ERIC Educational Resources Information Center

Krishen, Anoop

1989-01-01

This review covers methods for identification, characterization, and determination of rubber and materials in rubber. Topics include: general information, nuclear magnetic resonance spectroscopy, infrared spectroscopy, thermal methods, gel permeation chromatography, size exclusion chromatography, analysis related to safety and health, and…

Mössbauer studies of a martensitic transformation and of cryogenic treatments of a D2 tool steel

NASA Astrophysics Data System (ADS)

Costa, B. F. O.; Blumers, M.; Kortmann, A.; Theisen, W.; Batista, A. C.; Klingelhöfer, G.

2013-04-01

A D2 tool steel X153CrVMo12 with composition C1.53 Cr12 V0.95 Mo0.80 Mn0.40(wt% Fe balanced) was studied by use of Mössbauer spectroscopy and X-ray diffraction. It was observed that the study of carbides by X-ray diffraction was difficult while Mössbauer spectroscopy gives some light on the process occurring during cryogenic treatment. With the increase of the martensitic phase the carbides decrease and are dissolved in solid solution of martensite as well as the chromium element.

Label-free pathological evaluation of grade 3 cancer using Stokes shift spectroscopy

NASA Astrophysics Data System (ADS)

Sordillo, Laura A.; Sordillo, Peter P.; Alfano, R. R.

2016-03-01

In this study, Stokes shift spectroscopy (S3) is used for measuring the aggressiveness of malignant tumors. S3 is an optical tool which utilizes the difference between the emission wavelength (λem) and the absorption wavelength (λabs) (the Stokes shift) to give a fixed wavelength shift (Δλs).Our analysis of tumor samples using S3 shows grade 3 (high grade) cancers consistently have increased relative tryptophan content compared to grade 1 or 2 tumors. This technique may be a useful tool in the evaluation of a patient's cancer.

Neutron and gamma-ray energy reconstruction for characterization of special nuclear material

DOE PAGES

Clarke, Shaun D.; Hamel, Michael C.; Di fulvio, Angela; ...

2017-06-30

Characterization of special nuclear material may be performed using energy spectroscopy of either the neutron or gamma-ray emissions from the sample. Gamma-ray spectroscopy can be performed relatively easily using high-resolution semiconductors such as high-purity germanium. Neutron spectroscopy, by contrast, is a complex inverse problem. Here, results are presented for 252Cf and PuBe energy spectra unfolded using a single EJ309 organic scintillator; excellent agreement is observed with the reference spectra. Neutron energy spectroscopy is also possible using a two-plane detector array, whereby time-offlight kinematics can be used. With this system, energy spectra can also be obtained as a function of position.more » Finally, spatial-dependent energy spectra are presented for neutron and gamma-ray sources that are in excellent agreement with expectations.« less

Applications of synchrotron-based spectroscopic techniques in studying nucleic acids and nucleic acid-functionalized nanomaterials

PubMed Central

Wu, Peiwen; Yu, Yang; McGhee, Claire E.; Tan, Li Huey

2014-01-01

In this review, we summarize recent progresses in the application of synchrotron-based spectroscopic techniques for nucleic acid research that takes advantage of high-flux and high-brilliance electromagnetic radiation from synchrotron sources. The first section of the review focuses on the characterization of the structure and folding processes of nucleic acids using different types of synchrotron-based spectroscopies, such as X-ray absorption spectroscopy, X-ray emission spectroscopy, X-ray photoelectron spectroscopy, synchrotron radiation circular dichroism, X-ray footprinting and small-angle X-ray scattering. In the second section, the characterization of nucleic acid-based nanostructures, nucleic acid-functionalized nanomaterials and nucleic acid-lipid interactions using these spectroscopic techniques is summarized. Insights gained from these studies are described and future directions of this field are also discussed. PMID:25205057

Neutron and gamma-ray energy reconstruction for characterization of special nuclear material

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

Clarke, Shaun D.; Hamel, Michael C.; Di fulvio, Angela

Characterization of special nuclear material may be performed using energy spectroscopy of either the neutron or gamma-ray emissions from the sample. Gamma-ray spectroscopy can be performed relatively easily using high-resolution semiconductors such as high-purity germanium. Neutron spectroscopy, by contrast, is a complex inverse problem. Here, results are presented for 252Cf and PuBe energy spectra unfolded using a single EJ309 organic scintillator; excellent agreement is observed with the reference spectra. Neutron energy spectroscopy is also possible using a two-plane detector array, whereby time-offlight kinematics can be used. With this system, energy spectra can also be obtained as a function of position.more » Finally, spatial-dependent energy spectra are presented for neutron and gamma-ray sources that are in excellent agreement with expectations.« less

Applications of synchrotron-based spectroscopic techniques in studying nucleic acids and nucleic acid-functionalized nanomaterials

DOE PAGES

Wu, Peiwen; Yu, Yang; McGhee, Claire E.; ...

2014-09-10

In this paper, we summarize recent progress in the application of synchrotron-based spectroscopic techniques for nucleic acid research that takes advantage of high-flux and high-brilliance electromagnetic radiation from synchrotron sources. The first section of the review focuses on the characterization of the structure and folding processes of nucleic acids using different types of synchrotron-based spectroscopies, such as X-ray absorption spectroscopy, X-ray emission spectroscopy, X-ray photoelectron spectroscopy, synchrotron radiation circular dichroism, X-ray footprinting and small-angle X-ray scattering. In the second section, the characterization of nucleic acid-based nanostructures, nucleic acid-functionalized nanomaterials and nucleic acid-lipid interactions using these spectroscopic techniques is summarized. Insightsmore » gained from these studies are described and future directions of this field are also discussed.« less

Metabolomics As a Tool for the Characterization of Drug-Resistant Epilepsy.

PubMed

Murgia, Federica; Muroni, Antonella; Puligheddu, Monica; Polizzi, Lorenzo; Barberini, Luigi; Orofino, Gianni; Solla, Paolo; Poddighe, Simone; Del Carratore, Francesco; Griffin, Julian L; Atzori, Luigi; Marrosu, Francesco

2017-01-01

Drug resistance is a critical issue in the treatment of epilepsy, contributing to clinical emergencies and increasing both serious social and economic burdens on the health system. The wide variety of potential drug combinations followed by often failed consecutive attempts to match drugs to an individual patient may mean that this treatment stage may last for years with suboptimal benefit to the patient. Given these challenges, it is valuable to explore the availability of new methodologies able to shorten the period of determining a rationale pharmacologic treatment. Metabolomics could provide such a tool to investigate possible markers of drug resistance in subjects with epilepsy. Blood samples were collected from (1) controls (C) ( n  = 35), (2) patients with epilepsy "responder" (R) ( n  = 18), and (3) patients with epilepsy "non-responder" (NR) ( n  = 17) to the drug therapy. The samples were analyzed using nuclear magnetic resonance spectroscopy, followed by multivariate statistical analysis. A different metabolic profile based on metabolomics analysis of the serum was observed between C and patients with epilepsy and also between R and NR patients. It was possible to identify the discriminant metabolites for the three classes under investigation. Serum from patients with epilepsy were characterized by increased levels of 3-OH-butyrate, 2-OH-valerate, 2-OH-butyrate, acetoacetate, acetone, acetate, choline, alanine, glutamate, scyllo-inositol (C < R < NR), and decreased concentration of glucose, lactate, and citrate compared to C (C > R > NR). In conclusion, metabolomics may represent an important tool for discovery of differences between subjects affected by epilepsy responding or resistant to therapies and for the study of its pathophysiology, optimizing the therapeutic resources and the quality of life of patients.

Cancer diagnosis by infrared spectroscopy: methodological aspects

NASA Astrophysics Data System (ADS)

Jackson, Michael; Kim, Keith; Tetteh, John; Mansfield, James R.; Dolenko, Brion; Somorjai, Raymond L.; Orr, F. W.; Watson, Peter H.; Mantsch, Henry H.

1998-04-01

IR spectroscopy is proving to be a powerful tool for the study and diagnosis of cancer. The application of IR spectroscopy to the analysis of cultured tumor cells and grading of breast cancer sections is outlined. Potential sources of error in spectral interpretation due to variations in sample histology and artifacts associated with sample storage and preparation are discussed. The application of statistical techniques to assess differences between spectra and to non-subjectively classify spectra is demonstrated.

The Development of Pulsed Photoacoustic and Photothermal Deflection Spectroscopy as Diagnostic Tools for Combustion.

NASA Astrophysics Data System (ADS)

Rose, Allen Howard

The application of Photoacoustic Deflection Spectroscopy (PADS) and Photothermal Deflection Spectroscopy (PTDS) to the combustion environment has been made to determine the usefulness of these techniques in combustion diagnostics. Both theoretical models and experimental techniques have been developed. With these tools, PADS and PTDS, one can measure absolute species concentration, temperature, and flow velocity in the combustion environment. These techniques are nonintrusive, with a high sensitivity and excellent spatial and temporal resolution. With PADS it is possible to measure OH concentrations down to 1times 10^{14} OH molecules/cm^3 in a single shot and temperatures to an accuracy of ^{ ~}+/- 100{rm K}. With PTDS it is possible to measure OH concentrations down to 3times 10^{12} OH molecules/cm^3 in a single shot and velocities to an accuracy of ^{ ~}+/- 1{rm m/s} in a flame. Higher accuracies can be obtained with further improvements in the experimental apparatus. The disadvantages are: (1) the need for a strong absorbing species within the combustion environment to generate these signals, (2) the lack of knowledge about the major molecular species concentrations in the combustion environment, and (3) the lack of knowledge about the thermodynamic properties of these major species at combustion temperatures. PADS and PTDS would complement other techniques such as coherent anti-Stokes Raman spectroscopy (CARS), laser-induced fluorescence spectroscopy (LIFS), and optogalvanic spectroscopy.

Scanning electron and atomic force microscopy, and raman and x-ray photoelectron spectroscopy characterization of near-isogenic soft and hard wheat kernels and corresponding flours

USDA-ARS?s Scientific Manuscript database

Atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) are used to investigate vitreous (hard) and non-vitreous (soft) wheat kernels and their corresponding wheat flours. AFM data reveal two different microstructures. The vitreous kernel reveals a granular text...

Characterization of III-V Semiconductors.

DTIC Science & Technology

1981-04-01

Conversion Photoluminescence InP Hall Effect Mass Spectroscopy Ion Implantation Photoconductivity Donor-Acceptor 20. ABSTRACT (Continue on reverse side If...Characteristiss .. 72 10.0 FAR INFRARED STUDIES IN GaAs. ....................... 76I11.0 SPARK-SOURCE MASS SPECTROSCOPY IN GaAs...concen- tration, as measured by spark-source mass spectroscopy (SSMS), and the Hall 7 mobility. However, we found that, unfortunately, commercially

Polarization-resolved optical response of plasmonic particle-on-film nanocavities

NASA Astrophysics Data System (ADS)

Zhang, Q.; Li, G.-C.; Lo, T. W.; Lei, D. Y.

2018-02-01

Placing a metal nanoparticle atop a metal film forms a plasmonic particle-on-film nanocavity. Such a nanocavity supports strong plasmonic coupling that results in rich hybridized plasmon modes, rendering the cavity a versatile platform for exploiting a wide range of plasmon-enhanced spectroscopy applications. In this paper, we fully address the polarization-resolved, orientation-dependent far-field optical responses of plasmonic monomer- and dimer-on-film nanocavities by numerical simulations and experiments. With polarization-resolved dark-field spectroscopy, the distinct plasmon resonances of these nanocavities are clearly determined from their scattering spectra. Moreover, the radiation patterns of respective plasmon modes, which are often mixed together in common dark-field imaging, can be unambiguously resolved with our proposed quasi-multispectral imaging method. Explicitly, the radiation pattern of the monomer-on-film nanocavity gradually transitions from a solid spot in the green imaging channel to a doughnut ring in the red channel when tuning the excitation polarization from parallel to perpendicular to the sample surface. This observation holds true for the plasmonic dimer-on-film nanocavity with the dimer axis aligned in the incidence plane; when the dimer axis is normal to the incidence plane, the pattern transitions from a solid spot to a doughnut ring both in the red channel. These studies not only demonstrate a flexible polarization control over the optical responses of plasmonic particle-on-film nanostructures but also enrich the optical tool kit for far-field imaging and spectroscopy characterization of various plasmonic nanostructures.

X-ray Photoelectron Spectroscopy as a tool to investigate silane-based coatings for the protection of outdoor bronze: The role of alloying elements

NASA Astrophysics Data System (ADS)

Masi, G.; Balbo, A.; Esvan, J.; Monticelli, C.; Avila, J.; Robbiola, L.; Bernardi, E.; Bignozzi, M. C.; Asensio, M. C.; Martini, C.; Chiavari, C.

2018-03-01

Application of a protective coating is the most widely used conservation treatment for outdoor bronzes (cast Cu-Sn-Zn-Pb-Sb alloys). However, improving coating protectiveness requires detailed knowledge of the coating/substrate chemical bonding. This is particularly the case for 3-mercapto-propyl-trimethoxy-silane (PropS-SH) applied on bronze, exhibiting a good protective behaviour in outdoor simulated conditions. The present work deals with X-Ray Photoelectron Spectroscopy (XPS) and Electron Microscopy (FEG-SEM + FIB (Focused Ion Beam)) characterization of a thin PropS-SH film on bronze. In particular, in order to better understand the influence of alloying elements on coating performance, PropS-SH was studied first on pure Cu and Sn substrates then on bronzes with increasing alloy additions: Cu8Sn as well as a quinary Cu-Sn-Zn-Pb-Sb bronze. Moreover, considering the real application of this coating on historical bronze substrates, previously artificially aged ("patinated") bronze samples were prepared and a comparison between bare and "patinated" quinary bronzes was performed. In the case of coated quinary bronze, the free surface of samples was analysed by High Resolution Photoelectron Spectroscopy using Synchrotron Radiation (HR-SRPES) at ANTARES (Synchrotron SOLEIL), which offers a higher energy and lateral resolution. By compiling complementary spectroscopic and imaging information, a deeper insight into the interactions between the protective coating and the bronze substrate was achieved.

Discrimination of premalignant conditions of oral cancer using Raman spectroscopy of urinary metabolites

NASA Astrophysics Data System (ADS)

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

2015-03-01

Oral cancers are considered to be one of the most commonly occurring malignancy worldwide. Over 70% of the cases report to the doctor only in advanced stages of the disease, resulting in poor survival rates. Hence it is necessary to detect the disease at the earliest which may increase the five year survival rate up to 90%. Among various optical spectroscopic techniques, Raman spectroscopy has been emerged as a tool in identifying several diseased conditions, including oral cancers. Around 30 - 80% of the malignancies of the oral cavity arise from premalignant lesions. Hence, understanding the molecular/spectral differences at the premalignant stage may help in identifying the cancer at the earliest and increase patient's survival rate. Among various bio-fluids such as blood, urine and saliva, urine is considered as one of the diagnostically potential bio-fluids, as it has many metabolites. The distribution and the physiochemical properties of the urinary metabolites may vary due to the changes associated with the pathologic conditions. The present study is aimed to characterize the urine of 70 healthy subjects and 51 pre-malignant patients using Raman spectroscopy under 785nm excitation, to know the molecular/spectral differences between healthy subjects and premalignant conditions of oral malignancy. Principal component analysis based Linear discriminant analysis were also made to find the statistical significance and the present technique yields the sensitivity and specificity of 86.3% and 92.9% with an overall accuracy of 90.9% in the discrimination of premalignant conditions from healthy subjects urine.

Toroidal Optical Microresonators as Single-Particle Absorption Spectrometers

NASA Astrophysics Data System (ADS)

Heylman, Kevin D.

Single-particle and single-molecule measurements are invaluable tools for characterizing structural and energetic properties of molecules and nanomaterials. Photothermal microscopy in particular is an ultrasensitive technique capable of single-molecule resolution. In this thesis I introduce a new form of photothermal spectroscopy involving toroidal optical microresonators as detectors and a pair of non-interacting lasers as pump and probe for performing single-target absorption spectroscopy. The first three chapters will discuss the motivation, design principles, underlying theory, and fabrication process for the microresonator absorption spectrometer. With an early version of the spectrometer, I demonstrate photothermal mapping and all-optical tuning with toroids of different geometries in Chapter 4. In Chapter 5, I discuss photothermal mapping and measurement of the absolute absorption cross-sections of individual carbon nanotubes. For the next generation of measurements I incorporate all of the advances described in Chapter 2, including a double-modulation technique to improve detection limits and a tunable pump laser for spectral measurements on single gold nanoparticles. In Chapter 6 I observe sharp Fano resonances in the spectra of gold nanoparticles and describe them with a theoretical model. I continued to study this photonic-plasmonic hybrid system in Chapter 7 and explore the thermal tuning of the Fano resonance phase while quantifying the Fisher information. The new method of photothermal single-particle absorption spectroscopy that I will discuss in this thesis has reached record detection limits for microresonator sensing and is within striking distance of becoming the first single-molecule room-temperature absorption spectrometer.

Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

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

Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu

2015-07-28

Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent developmentmore » in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES.« less

Magnetic Resonance Spectroscopy: An Objective Technique for the Quantification of Prostate Cancer Pathologies

DTIC Science & Technology

2007-02-01

5d. PROJECT NUMBER Leo L. Cheng, Ph.D. 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S...Scott RM, Anthony DC, Gonzalez RG, Black PM. Biochemical characterization of pediatric brain tumors by using in vivo and ex vivo magnetic resonance...Biochemical characterization of pediatric brain tumors by using in vivo and ex vivo magnetic resonance spectroscopy. J Neurosurg 2002;96: 1023–1031. 7

Raman structural studies of the nickel electrode

NASA Technical Reports Server (NTRS)

Cornilsen, Bahne C.

1994-01-01

The objectives of this investigation have been to define the structures of charged active mass, discharged active mass, and related precursor materials (alpha-phases), with the purpose of better understanding the chemical and electrochemical reactions, including failure mechanisms and cobalt incorporation, so that the nickel electrode may be improved. Although our primary tool has been Raman spectroscopy, the structural conclusions drawn from the Raman data have been supported and augmented by three other analysis methods: infrared spectroscopy, powder X-ray Diffraction (XRD), and x-ray absorption spectroscopy (in particular EXAFS, Extended X-ray Absorption Fine Structure spectroscopy).