bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring Decay of Black Gum Wood (Nyssa Sylvatica) during Growth of the Shiitake Mushroom (Lentinula edodes) Using Diffuse Reflectance Infrared Spectroscopy
Authors: Vane Christopher H.
Published: October 2003

Abstract diffuse reflectance infrared spectroscopy (DRIFT) and elemental analysis were employed to monitor biodegradation of black gum wood ( Nyssa sylvatica) during growth of the shiitake mushroom ( Lentinula edodes). Black gum was decayed for up to 4.3 years by L. edodes, during which time it was sampled at 19, 31, and 52 months. Biodegraded woods displayed increased % O (w/w) and decreased % C (w/w) relative to the undecayed control. The DRIFT spectra of decayed black gum showed a decrease in relative intensity of absorption bands at 1735 cm−1 assigned to carboxyl functional groups from xylans and an increase in the absorption band at 1640 cm−1 assigned to conjugated carbonyl groups originating from lignin. Xylan decay was rapid initially but slowed after 19 months; however, oxidative decay of the lignin side chains occurred throughout the 52-month decay period. Overall elemental and DRIFT data show that both polysaccharides and lignin were decayed during cultivation of the edible white-rot fungus.
Surface-Sensitive Molecular Information on Polymers from UV-Resonance Raman Spectroscopy
Authors: Wang Jiann-Hua , Klenerman David , Van Der Pol André , Meier Robert J.
Published: October 2003

Ultraviolet resonance Raman spectroscopy (UV-RRS) has been applied to a series of samples of poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) and poly(ethylene terephthalate) (PET) of varying thickness. The spectra demonstrate that under resonance conditions, when absorption is very strong, only a very thin top layer of the sample is probed (hundreds of nanometers range). This allows probing molecular vibrational spectra of the top layer of the sample, with a surface-resolution at least an order of magnitude better than in the case of normal non-resonance Raman spectroscopy and using a microscope.
Raman Spectroscopy-Based Creatinine Measurement in Urine Samples from a Multipatient Population
Authors: McMurdy John W. , Berger Andrew J.
Published: October 2003

Spectroscopic methods of urinalysis offer several advantages over chemical methods, including less sample contact and higher information content. In particular, urine creatinine has been the subject of several spectroscopic studies. We report the first use of Raman spectroscopy to measure creatinine concentrations in unaltered urine samples from a multipatient population. Using near-infrared excitation and a hybrid linear analysis calibration method, a root mean squared error of cross-validation (RMSECV) of 4.9 mg/dL was obtained. The error in the reference chemical method was 1.1 mg/dL. This result shows that the Raman spectroscopy can measure creatinine at clinical levels even in the presence of patient-to-patient variations. Because most assays in urine require creatinine concentration in order to correct for fluctuations in water content, measurement of creatinine is the first step towards more extensive Raman-based urinalysis.
Photodeposition of Silver Can Result in Metal-Enhanced Fluorescence
Authors: Geddes Chris D. , Parfenov Alexandr , Lakowicz Joseph R.
Published: October 2003

Chemically deposited silver particles are widely used for surface-enhanced Raman scattering (SERS) and more recently for surface-enhanced fluorescence (SEF), also known as metal-enhanced fluorescence (MEF). We now show that metallic silver deposited by laser illumination results in an ∼7-fold increased intensity of locally bound indocyanine green. The increased intensity is accompanied by a decreased lifetime and increased photostability. These results demonstrate the possibility of photolithographic preparation of surfaces for enhanced fluorescence in microfluidics, medical diagnostics, and other applications.
Self-Referencing Intensity Measurements Based on Square-Wave Gated Phase-Modulation Fluorimetry
Authors: Rowe H. M. , Chan Sing Po , Demas J. N. , DeGraff B. A.
Published: October 2003

An adaptation of square-wave gated phase-modulation (GPM) fluorimetry allows for self-referenced intensity measurements without the complexity of dual excitation or dual emission wavelengths. This AC technique utilizes square-wave excitation, gated detection, a reference emitter, and a sensor molecule. The theory and experimental data demonstrating the effectiveness and advantages of the adapted GPM scheme are presented. One component must have an extremely short lifetime relative to the other. Both components are affected identically by changes in intensity of the excitation source, but the sensor intensity also depends on the concentration of the analyte. The fluctuations of the excitation source and any optical transmission changes are eliminated by ratioing the sensor emission to the reference emission. As the concentration of the analyte changes, the corresponding sensor intensity changes can be quantified through several schemes including digitization of the signal and digital integration or AC methods. To measure pH, digital methods are used with Na3[Tb(dpa)3] (dpa = 2,6-pyridinedicarboxylic acid) as the long-lived reference molecule and fluorescein as the short-lived sensor molecule. Measurements from the adapted GPM scheme are directly compared to conventional ratiometric measurements. Good agreement between the data collection methods is demonstrated through the apparent pKa. For the adapted GPM measurements, conventional measurements, and a global fit the apparent pKa values agree within less than 2%. A key element of the adapted GPM method is its insensitivity to fluctuations in the source intensity. For a roughly 8-fold change in the excitation intensity, the signal ratio changes by less than 3%.
New Approach to Generalized Two-Dimensional Correlation Spectroscopy. III: Eigenvalue Manipulation Transformation (EMT) for Spectral Selectivity Enhancement
Authors: Jung Young Mee , Kim Seung Bin , Noda Isao
Published: October 2003

This paper demonstrates the potential of eigenvalue manipulating transformation (EMT) of a data matrix for spectral selectivity enhancement, especially useful in 2D correlation analysis. The EMT operation aims at the accentuation of select features of the information content of the original data matrix. For example, by uniformly lowering the power of a set of eigenvalues associated with the original data, the smaller eigenvalues become more prominent and the contributions of secondary loadings become amplified. As a direct consequence of the minor factor accentuation by such EMT operations, 2D correlation spectra gain much stronger discriminating power. The selectivity enhancement effect of such manipulation of eigenvalues is much more noticeable on the synchronous 2D correlation spectrum. This improvement for the spectral selectivity of synchronous 2D correlation spectra is potentially very important, as we usually put more emphasis on the interpretation of asynchronous 2D spectra in 2D correlation analysis due to overlaps of synchronous peaks. Such EMT operations tend to exaggerate the information content of minor PCs and reduce that of major PCs. Thus, much more subtle difference of spectral behavior for each component is now highlighted. Surprisingly, asynchronous 2D correlation spectra are found to be much less sensitive to such EMT operations. The result indicates that the distinction of different band responses has already been accomplished effectively by the original asynchronous 2D correlation analysis.
Application of Mid-Infrared Spectroscopy: Measuring Hydrogen Peroxide Concentrations in Bleaching Baths
Authors: Voraberger Hannes , Ribitsch Volker , Janotta Markus , Mizaikoff Boris
Published: October 2003

The presented work applies mid-infrared attenuated total reflection (ATR) spectroscopy to the measurment of hydrogen peroxide in aqueous matrices. The performance of different ATR crystals mounted in flow cells was investigated in the presence of aqueous hydrogen peroxide solutions. Quantitative determination has been achieved by evaluation of specific OH stretching and deformation vibrations with linear correlation between peak areas or peak heights and hydrogen peroxide concentration in the range of 1–10% (weight in water). Important aspects such as chemical stability of the waveguide material and influences of pH and ionic strength on the performance are discussed. Feasibility for the investigation of real world samples is demonstrated by measuring industrial bleaching solutions with known concentrations of hydrogen peroxide fitting well with calibration graphs established with neat hydrogen peroxide solutions. The presented sensor system is capable of determining hydrogen peroxide within complex matrices and clearly corroborates the potential of providing an in situ measurement concept for on-line hydrogen peroxide detection.
Surface-Enhanced Resonance Raman Scattering: Single-Molecule Detection in a Langmuir—Blodgett Monolayer
Authors: Constantino Carlos J. L. , Lemma Tibebe , Antunes Patricia A. , Goulet Paul , Aroca Ricardo
Published: October 2003

Surface-enhanced resonance Raman scattering (SERRS) is used for single-molecule detection from spatially resolved 1-μm2 sections of a Langmuir–Blodgett (LB) monolayer deposited onto a Ag film. The target molecule, bis (benzimidazo) thioperylene (BZP), is dispersed in an arachidic acid monomolecular layer containing one BZP molecule per μm2, which is also the probing area of the Raman microscope. For concentrated samples (attomole quantities in the field of view), average SERRS, surface-enhanced fluorescence (SEF), and Raman imaging, including line mapping and global images at different temperatures, were recorded. Single-molecule SERRS spectra, obtained using an LB monolayer, present changes in bandwidth and relative intensities, highlighting the properties of single-molecule SERRS that are lost in average SERRS measurements of mixed LB monolayers obtained at the same temperatures. Also, the dilute system phenomenon of blinking is discussed with regard to results obtained from LB monolayers. The dilution process used in the single-molecule LB SERRS work is independently supported by fluorescence results obtained from very dilute solutions with monomer concentrations down to 10−12 M.
Near-Infrared Spectroscopic Monitoring of the Diffusion Process of Deuterium-Labeled Molecules in Wood. Part II: Hardwood
Authors: Tsuchikawa Satoru , Siesler H. W.
Published: October 2003

Fourier transform near-infrared (FT-NIR) transmission spectroscopy was applied to monitor the diffusion process of deuterium-labeled molecules in hardwood (Beech). The results are compared with previous data obtained on softwood (Sitka spruce) in order to consistently understand the state of order in cellulose of wood. The saturation accessibility and diffusion rate varied characteristically with the OH groups in different states of order in the wood substance, the diffusants, and the wood species, respectively. The variation of saturation accessibility should be associated with the fundamental difference of the fine structure such as the microfibrils in the wood substance. The effect of the anatomical cellular structure on the accessibility was reflected in the variation of the diffusion rate with the wood species. The size effect of the diffusants also played an important role for the diffusion process in wood. Since the volumetric percentage of wood fibers and wood rays is relatively similar, the dichroic effects due to the anisotropy of the cellulose chains were apparently diminished. Finally, we proposed a new interpretation of the fine structure of the microfibrils in the cell wall by comparing a series of results from hardwood and softwood. Each elementary fibril in the hardwood has a more homogeneous arrangement in the microfibrils compared to that in the softwood.
Development and Application of Acousto-Optic Background Correction for Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Miller Heather M. , Spudich Thomas M. , Carnahan Jon W.
Published: October 2003

In two configurations, a solid-state acousto-optic (AO) deflector or modulator is mounted in a 0.5 m monochromator for background correction with inductively coupled plasma atomic emission spectrometry (ICP-AES). A fused silica acousto-optic modulator (AOM) is used in the ultraviolet (UV) spectral region applications while a glass AO deflector (AOD) is used for the visible (VIS) region. The system provides rapid sequential observation of adjacent on- and off-line wavelengths for background correction. Seventeen elements are examined using pneumatic nebulization (PN) and electrothermal vaporization (ETV) sample introduction. Calibration plots were obtained with each sample introduction technique. Potable water and vitamin tablets were analyzed. Flame atomic absorption (FAA) was used to verify the accuracy of the AO background correction system.
Temporal and Spatial Evolution of a Laser-Induced Plasma from a Steel Target
Authors: Corsi M. , Cristoforetti G. , Hidalgo M. , Iriarte D. , Legnaioli S. , Palleschi V. , Salvetti A. , Tognoni E.
Published: October 2003

The space and time evolution of a laser-induced plasma from a steel target has been studied using optical time-of-flight and shadowgraphic techniques. The results, obtained for two distinct laser energy regimes, allow us to individuate two different regions in the plume, one characterized by air and continuum emissions produced by the shock wave ionization and the other characterized by emissions from ablated material. Moreover, it was shown that a sufficiently high laser fluence and short delay time of acquisition are needed to avoid inhomogeneous effects in the plasma, as required in analytical applications such as laser-induced breakdown spectroscopy.
Multi-Wavelength Raman Imaging Using a Small-Diameter Image Guide with a Dimension-Reduction Imaging Array
Authors: Carter J. Chance , Scrivens Wally A. , Myrick M. L. , Angel S. Michael
Published: October 2003

A commercially available fiber-optic Raman probe was modified for high-resolution spectral Raman imaging using a 350 μm diameter optical fiber image guide coupled to a dimension-reduction imaging array (DRIA). The DRIA comprised 672 optical fibers, arranged as a square array (21 × 32 fibers) on one end and a linear array (672 × 1 fibers) on the other. An imaging spectrograph was used with the DRIA to acquire multi-wavelength Raman images from −250 to 1800 cm−1 at a spectral resolution of ∼5 cm−1. The utility of this technique for in situ and remote Raman imaging is demonstrated by monitoring the polymerization of a model polymer, dibromostyrene (DBS), while simultaneously measuring the Raman Stokes/anti-Stokes ratio as a function of sample heating time, over a sample area of ∼4 × 1.6 mm.
Raman Spectroscopy as a Tool for Measuring Mutual-Diffusion Coefficients in Hydrogels
Authors: Kwak Sungjong , Lafleur Michel
Published: October 2003

Raman spectroscopy has been exploited to characterize the diffusion properties of solutes in hydrogels. Raman active vibrations were used as intrinsic probes of the solute concentration along gel cylinders. The resulting one-dimensional solute distribution, characterized as a function of both time and space, could be analyzed with a model based on Fick's diffusion law, and the mutual-diffusion coefficient ( Dm) was then determined. To illustrate the potential of this approach, we measured the Dm of two polyethylene glycols (PEG) in Ca–alginate gels. In this case, the intensity of the CH stretching band was used to obtain the concentration profiles of PEGs, whereas the OH stretching band of water was used as an internal intensity standard. In addition to providing a straightforward approach to measuring diffusion coefficients, the Raman profile analysis provides information relative to the accessibility of gels to large molecules. As an example, it was found that the PEG penetration in Ca–alginate gels was restricted, a phenomenon that was dependent on PEG size. The Raman technique presented here effectively characterizes transport properties of solutes in gels, and such characterization is required for developing several technical applications of gels, such as their use as materials for controlled release of drugs.
Sol-Gel-Coated Mid-Infrared Fiber-Optic Sensors
Authors: Janotta Markus , Katzir Abraham , Mizaikoff Boris
Published: October 2003

Application of organically modified sol-gels as novel recognition membranes for mid-infrared fiber-optic sensors is demonstrated for the first time by in situ detection of nitro-based aromatic compounds in aqueous media. Sol-gels were prepared by acid- and base-catalyzed copolymerization of alkyltrimethoxysiloxanes and applied onto the surface of silver halide (AgCl0.3Br0.7) fibers by drip coating. The coating process was monitored in situ using Fourier transform infrared (FT-IR) spectroscopy. Homogeneity of the layers was analyzed by scanning electron microscopy. Sol-gel-coated evanescent field sensors were investigated with respect to their capacity to suppress interfering water background absorptions, repeatability of dissolved analyte enrichment, and sensor response time. Nitrobenzene and parathion are the investigated analytes; figures of merit are derived from calibration curves determined to assess sensitivity and reproducibility of the developed sensor system. It can be concluded that sol-gel-coated infrared fiber-optic sensors enable reproducible detection of nitro-based aromatic compounds in the low ppm concentration range. Due to wide flexibility in tuning chemical properties of sol-gel films along with superior mechanical and chemical stability, organically modified sol-gels represent highly interesting coating materials for mid-infrared sensing applications.
FT-IR Study of a Chemically Amplified Resist for X-ray Lithography
Authors: Tan T. L. , Kudryashov V. A. , Tan B. L.
Published: October 2003

Microelectronic devices for future applications demand lithographic performance that falls within the 0.10 μm region and below. Chemically amplified resists (CARs), such as the positive tone commercial UVIII resist, offer a substantial gain in sensitivity, resolution, and process efficiency in deep ultraviolet, e-beam, and X-ray lithographies. In this work, the UVIII resist is characterized for X-ray lithographic applications by studying the “deprotection” or acid generation–diffusion process of the resist under different conditions of post-exposure bake (PEB) temperature and time, and of X-ray exposure dose. The X-ray irradiation from a copper anode at a wavelength of 1.33 nm was at an intensity of 30 μW/cm2 on the resist surface. The deprotection process of the resist during PEB was accurately monitored by using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 1151, 1369, and 2977 cm−1 in the spectrum of the UVIII resist were found to be useful indicators for the completion of deprotection. Results of the experiments showed that the performance of UVIII could be optimized at the PEB temperature of 140 °C, a time of 2 min, and X-ray exposure dose of 12 mJ/cm2. The change in resist thickness after PEB was also measured. The results were confirmed by scanning electron microscopy (SEM) in which a test structure as small as 0.12 μm was obtained in a 1-μm-thick UVIII resist layer.
Resonance Raman Spectroscopy of Photolabile Transition Metal Carbonyls: Controlled Photoalteration with Continuous Wave Lasers to Record Spectra of Reactants or Transient Species
Authors: Abbott Laurence C. , Feilden Caroline J. , Anderton Clare L. , Moore John N.
Published: October 2003

A method has been developed that enables resonance Raman spectra of photolabile species in solution to be recorded under conditions where the level of photoalteration is controlled: a low level enables reactant spectra to be recorded, whereas a high level enables the spectra of short-lived transient species to be recorded in real time using continuous-wave (CW) lasers and standard Raman detection equipment. The design includes a sealed flow system, enabling air-sensitive species to be studied under an inert atmosphere. A simple theoretical model has been developed to aid the interpretation of experimental results, and its applicability is demonstrated. Controlled photoalteration and its theory are demonstrated with 413.1-nm excitation of carbonmonoxymyoglobin (MbCO), which generates deoxymyoglobin (deoxy-Mb) on photolysis, and for which the spectra of both species are well established. The methods have also been applied to two air-sensitive, photolabile transition metal carbonyls using 514.5-nm wavelength excitation: for Cp2Mo2(CO)6 (Cp = η5–C5H5), increasing levels of photoalteration result only in a decrease in the parent band intensities, relative to the solvent bands; for Cp2Fe2(CO)4, increasing levels of photoalteration result in the appearance of additional bands that are assigned to the transient species CpFe(μ–CO)3FeCp, formed following the loss of a CO ligand.
P—N Bond Length Alterations Monitored by Infrared Absorption and Fourier Transform Raman Spectroscopy in Combination with Density Functional Theory Calculations
Authors: Bolboaca M. , Stey T. , Murso A. , Stalke D. , Kiefer W.
Published: October 2003

Fourier transform (FT) Raman and infrared spectroscopy in combination with density functional theory calculations have been applied to the vibrational characterization of the dimeric zinc diphenylphosphanyl(trimethylsilyl)amide complex [(Me3Si)2NZnPh2PNSiMe3]2 and the ortho-metallated species [Li( o-C6H4PPh2NSiMe3)]2·Et2O in relation to their parent starting materials diphenylphosphanyl (trimethylsilyl)amine Ph2P–N(H)SiMe3 and iminophosphorane Ph3P=NSiMe3. The spectroscopic changes evidenced in the spectra were correlated with the structural parameters in order to provide insight as to what extent the P–N bond is affected by the coordination to the metal center. The employment of density functional theory (DFT) calculations in addition to these spectroscopic methods offers the possibility of predicting whether the Lewis-basic imido nitrogen atom is involved in coordination not only in the solid state, but also in the gas phase.
Characterization of the Electrochemical Reactions in the Li1+xV3O8/Li Cell by Soft X-ray Absorption Spectroscopy and Two-Dimensional Correlation Analysis
Authors: Choi Hyun Chul , Jung Young Mee , Kim Seung Bin
Published: October 2003

We applied soft X-ray absorption spectroscopy (XAS) and two-dimensional (2D) correlation analysis to the first lithium insertion–extraction cycle in a Li1+xV3O8/Li cell in order to investigate the electrochemical reactions of lithium with the Li1+xV3O8 electrode. The V LII,III-edge and O K-edge spectra of the Li1+xV3O8 electrode were obtained for varying electrode lithium content. The insertion of lithium leads to the reduction of the V5+ species present in the pristine Li1+xV3O8 electrode, and to the red shift and the broadening of the spectral features of the V LII,III edge compared to those of the pristine electrode. In the extraction process, the main spectral features at the highest value of the extraction of lithium show some differences compared to the features of the pristine electrode spectrum due to the residual lithium ions in the Li1+xV3O8 structure. The O K-edge spectra revealed that the insertion of lithium mainly affects the V 4sp–O 2p bonds and consequently induces a change in bonding geometry. The 2D correlation analysis of these spectra clearly shows that V–O bonds are significantly perturbed by the insertion–extraction of lithium into the Li1+xV3O8 electrode.
Aqueous Solutions of Uranium(VI) as Studied by Time-Resolved Emission Spectroscopy: A Round-Robin Test
Authors: Billard Isabelle , Ansoborlo Eric , Apperson Kathleen , Arpigny Sylvie , Azenha M. Emilia , Birch David , Bros Pascal , Burrows Hugh D. , Choppin Gregory , Couston Laurent , Dubois Veronique , Fanghänel Thomas , Geipel Gerhard , Hubert Solange , Kim Jae I. , Kimura Takaumi , Klenze Reinhardt , Kronenberg Andreas , Kumke Michael , Lagarde Gerard , Lamarque Gerard , Lis Stefan , Madic Charles , Meinrath Gunther , Moulin Christophe , Nagaishi Ryuji , Parker David , Plancque Gabriel , Scherbaum Franz , Simoni Eric , Sinkov Sergei , Viallesoubranne Carole
Published: October 2003

Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO22+aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.
Identification of Oil Contaminants on Polymer Coated Beverage Cans Using Fluorescence Spectroscopy
Authors: Malecha Michael , Bessant Conrad , Saini Selwayan
Published: October 2003

In a recent publication we introduced a novel method for detection of impurities on beverage can surfaces using Raman spectroscopy. While investigating the technique, limitations emerged due to the low sensitivity of Raman scatter. This is a particular problem with the largest contributor of impurities in beverage cans: lubricants employed in the manufacturing process. This paper presents an alternative approach, using the more sensitive technique of fluorescence spectroscopy to tackle the same problem. Measurements using fluorescence spectroscopy were conducted indirectly in a cuvette as well as directly on a can surface with the aid of fiber optics. The chemometrics methods of linear discriminant analysis (LDA) and principal components analysis (PCA) were used to classify acquired spectra as belonging to one of the 16 investigated lubricants. Fiber-optic scans revealed that a successful detection and recognition of lubricant is possible down to a volume of 0.5 μL deposited on the can surface. Contaminant detection was possible at even lower levels down to 0.01 μL, but reliable identification proved difficult at such low volumes. Indirect measurements of lubricants dissolved in cyclohexane yielded the lowest detection limits between 1–0.1 ppb.
Development of a Broadband Picosecond Infrared Spectrometer and its Incorporation into an Existing Ultrafast Time-Resolved Resonance Raman, UV/Visible, and Fluorescence Spectroscopic Apparatus
Authors: Towrie Michael , Grills David C. , Dyer Joanne , Weinstein Julia A. , Matousek Pavel , Barton Robin , Bailey Philip D. , Subramaniam Naresh , Kwok Wai M. , Ma Chensheng , Phillips David , Parker Anthony W. , George Michael W.
Published: October 2003

We have constructed a broadband ultrafast time-resolved infrared (TRIR) spectrometer and incorporated it into our existing time-resolved spectroscopy apparatus, thus creating a single instrument capable of performing the complementary techniques of femto-/picosecond time-resolved resonance Raman (TR3), fluorescence, and UV/visible/infrared transient absorption spectroscopy. The TRIR spectrometer employs broadband (150 fs, ∼150 cm−1 FWHM) mid-infrared probe and reference pulses (generated by difference frequency mixing of near-infrared pulses in type I AgGaS2), which are dispersed over two 64-element linear infrared array detectors (HgCdTe). These are coupled via custom-built data acquisition electronics to a personal computer for data processing. This data acquisition system performs signal handling on a shot-by-shot basis at the 1 kHz repetition rate of the pulsed laser system. The combination of real-time signal processing and the ability to normalize each probe and reference pulse has enabled us to achieve a high sensitivity on the order of ΔOD ∼ 10−4–10−5 with 1 min of acquisition time. We present preliminary picosecond TRIR studies using this spectrometer and also demonstrate how a combination of TRIR and TR3 spectroscopy can provide key information for the full elucidation of a photochemical process.
Spectroscopic Evaluation of the Effect of a Red Microalgal Polysaccharide on Herpes-Infected Vero Cells
Authors: Huleihel Mahmoud , Talyshinsky Marina , Souprun Yelena , Erukhimovitch Vitaly
Published: October 2003

The sulfated polysaccharide obtained from a species of red microalga has proved to be a potent antiviral agent against various members of the herpes family. In the present study, we used microscopic Fourier transform infrared spectroscopy (FT-IR) to investigate differences between normal cells, those infected with herpes viruses, and infected cells treated with red microalgal polysaccharide. FT-IR enables the characterization of cell or tissue pathology based on characteristic molecular vibrational spectra of the cells. The advantage of microscopic FT-IR spectroscopy over conventional FT-IR spectroscopy is that it facilitates inspection of restricted regions of cell cultures or tissue. Our results showed significant spectral differences at early stages of infection between infected and noninfected cells, and between infected cells treated with the polysaccharide and those not treated. In infected cells, there was an impressive decrease in sugar content and a considerable increase in phosphate levels in conjunction with the infection progress. Our results also proved that sugars penetrated and accumulated inside cells treated with the red microalgal polysaccharide. These could have been sugar fragments of low molecular weight present in the polysaccharide solution, despite purification by dialysis. Such sugar accumulation might be responsible for a breakdown in the internal steps of the viral replication cycle.
Multi-Wavelength Fluorescence-Quenching Model for Determination of Cu2+ Conditional Stability Constants and Ligand Concentrations of Fulvic Acid
Authors: Hays Michael D. , Ryan David K. , Pennell Stephen
Published: October 2003

In this work, a multi-wavelength model (MWM) is developed. It uses fluorescence bands in the fulvic acid (FA) spectrum that quench upon binding of inorganic Cu2+ to FA. Quenching data at pH values of 5, 6, and 7 are placed in sets, containing fluorescence measures at select wavelengths versus added copper ( CM). Intensity data of wavelength set 1 are obtained from 25 nm constant offset synchronous fluorescence spectra (SyF), in which are observed distinct peaks (λex = 415 nm, λem = 440 nm; and λex = 471 nm, λem = 496 nm). Wavelength set 2 intensity data are obtained from the FA fluorescence excitation and emission maxima (λex = 335 nm, λem = 450 nm; and λex = 471 nm, λem = 496 nm). Application of MWM shows that the multi-wavelength data sets characterize ligands of different binding strength (log Kx) and concentration ( CLx). Corresponding to pH values of 5, 6, and 7, mean and standard deviation values for wavelength set 1 are log K415/440 = 4.66 (0.12), 5.03 (0.12), and 5.05 (0.08), log K471/496 = 4.93 (0.06), 5.27 (0.11), and 5.39 (0.09), C415/440 = 3.1 (1.5), 10.9 (4.5), and 7.9 (3.9) μM, C471/496 = 14.3 (3.0), 1.7 (0.6), and 1.4 (0.5) μM. And for wavelength set 2, log K335/450 = 4.50 (0.03), 4.96 (0.27), and 5.22 (0.08), log K471/496 = 5.02 (0.04), 5.42 (0.32), and 5.71 (0.09), C335/450 = 8.8 (0.5), 21.9 (7.9), and 18.7 (0.3) μM, C471/496 = 21.0 (2.5), 7.17 (1.2), and 7.09 (0.3) μM. The ability of the 415/440 nm SyF transect to characterize the main excitation and emission maximum of FA at 335/440 nm is evaluated. Relatively low concentration values returned by the model for this transect (415/440 nm) suggest that it is not entirely illustrative of the maximum. The model predictive capability is verified at pH 6 with two fluorescing Cu2+ chelating organic compounds, L-tyrosine and salicylic acid. This test confirms that the model is capable of providing good estimates of equilibrium binding parameters from multi-wavelength measurements of a mixed ligand system.
Determining Water Content in Human Nails with a Portable Near-Infrared Spectrometer
Authors: Egawa Mariko , Fukuhara Tadao , Takahashi Motoji , Ozaki Yukihiro
Published: October 2003

The water content of human nail plates was determined using a portable near-infrared (NIR) spectrometer with an InGaAs photodiode array detector. NIR diffuse reflectance (DR) spectra were collected from 108 cut nail plates with different relative humidity and in vivo from fingernails. Partial least-squares (PLS) regression was applied to the NIR spectra in the 1115–1645 nm region to develop calibration models that determine the water content in the cut nail plates and fingernails. A good correlation was obtained between the NIR spectra and the water content measured by nuclear magnetic resonance (NMR) for the NIR measurement of both cut nail plates and fingernails. The results indicate that the water content in the nails can be determined very rapidly (1 s) by means of the portable NIR spectrometer and PLS regression.
Observation of Fourier Transform Near-Infrared Vibrational Circular Dichroism to 6150 cm−1
Authors: Nafie Laurence A. , Dukor Rina K. , Roy Jean-René , Rilling Allan , Cao Xiaolin , Buijs Henry
Published: October 2003

We report here the first measurement of near-infrared (NIR) vibrational circular dichroism (VCD) with Fourier transform (FT) instrumentation. The measurements were carried out using a commercial rapid-scan FT-IR VCD spectrometer modified for operation in the NIR region between 3750 and 6150 cm−1. Overtone and combination band VCD intensities, first reported by Keiderling and Stephens using dispersive VCD instrumentation in 1976, were reproduced with equivalent signal quality and spectral resolution using collection times of only a few minutes. These results offer substantial promise for the routine use of rapid-scan FT instrumentation for the measurement of overtone and combination band VCD spectra in the NIR region.
Fourier Transform Infrared Synchrotron Ellipsometry for Studying the Anisotropy of Small Organic Samples
Authors: Hinrichs K. , Gensch M. , Röseler A. , Korte E. H. , Sahre K. , Eichhorn K.-J. , Esser N. , Schade U.
Published: October 2003

An experimental setup for polarization-dependent and spectroscopic ellipsometric measurements was developed that utilizes the brilliance of synchrotron infrared radiation at the electron storage ring at BESSY II for investigations of small samples and sample areas. During commissioning of the beamline and the experimental setup, a 1 mm2 piece of a well-characterized polyimide film was studied to show the benefits of Fourier transform infrared (FT-IR) synchrotron ellipsometry. The band shapes are interpreted with respect to the anisotropic distribution of transition dipole moments within the film. In comparison to a globar source, the signal intensity has been improved by more than one order of magnitude for this example.
Diffuse Reflection Infrared Fourier Transform (DRIFT) Spectra and High-Temperature DRIFT Spectra of β—Ni(IO3)2·4H2O, Ni(IO3)2·2H2O, Mg(OH)2, and Zn(OH)F: Novel Embedding Materials
Authors: Pracht G. , Weckler B. , Lutz H. D.
Published: October 2003

Diffuse reflection infrared Fourier transform (DRIFT) spectra of the hydroxides Mg(OH)2 and Zn(OH)F and the iodate hydrates β–Ni(IO3)2·4H2O and Ni(IO3)2·2H2O have been recorded at ambient and high temperature. Spectra without shifts of the band maxima compared to those of conventional infrared transmission spectra and without inversion of the bands were obtained by dilution of the compounds to about 2–10% with an appropriate embedding material. α–Al2O3, TiO2, ZrO2, PbF2, MgO, BaO, ZnO, Na2SiO3, SiO2 (aerosil), and powdered copper, aluminum, and magnesium were tested as diluents for hydrates and hydroxides, especially at elevated temperatures, as alternatives for the commonly used KBr. Thus, α–Al2O3, PbF2, and powdered copper were established as the most favorable diluents. Using these novel embedding materials, high-temperature DRIFT spectra are obtainable at temperatures not accessible with KBr discs. Dehydration and decomposition of the iodate hydrates under study were shown by change or disappearance of the respective water bands.
Infrared Reflection—Absorption Spectra of Metal-Effect Coatings
Authors: Gunde Marta Klanjšek , Kunaver Matjaž
Published: October 2003

The results of studies of infrared reflection–absorption spectra of metal-effect coatings are presented in this paper. Such coatings consist of metallic flakes that are dispersed in a polymer binder. The spectra show two distinct phenomena. One is due to the polymer matrix. The other is due to metallic flakes that are dispersed inside the layer. The polymer binder causes narrow spectral lines that give a thickness-dependent intensity and position. Metallic flakes change the average baseline of this spectrum over the entire infrared spectral region. This particular effect was evaluated using a simple rough-surface model. Two parameters of the model, the root-mean-square roughness and the correlation length of the rough surface, described the reflection of the partial beams on the metal flake surfaces and scattering on flakes boundaries. The other two parameters are the specular reflectance and the diffuse reflectance of the plane untextured interface between the polymer matrix and the metal flake surface. Various metal-effect coatings within the same polymer binder were analyzed. The effect of each metal flake dispersion was evaluated by the parameters within the rough-surface model. The results were analyzed in terms of the size and the loadings of flakes that were used in the coatings.
Crystal—Smectic G Transformation Investigated by Temperature-Dependent Raman Study
Authors: Singh Ranjan K. , Schlücker S. , Asthana B. P. , Kiefer W.
Published: October 2003

We report on a temperature-dependent Raman study of terephthalidine-bis-butylaniline (TBBA) and terephthalidine-bis-heptylaniline (TB7A) in the temperature range 10–406 K and in the wavenumber regions 1120–1240 cm−1 and 1500–1700 cm−1. The variations of peak positions and linewidths of several Raman marker bands with temperature, which clearly show crystal–SmG transition at ∼334 K, have been used to discuss the dynamics of this phase transition. The temperature-dependent Raman study revealed that the increased vibration of the long alkyl tail and the rotation around the long molecular axis are the two primary phenomena responsible for the crystal–SmG transition. Density functional theory (DFT) at the B3LPY/6-31G(d) level was employed to obtain the optimized geometry and the harmonic vibrational wavenumbers of TBBA. The eigenvectors of the modes corresponding to these marker bands were also calculated.
Laser-Induced Differential Fluorescence for Cancer Diagnosis without Biopsy
Authors: Vo-Dinh Tuan , Panjehpour Masoud , Overholt Bergein F. , Buckley Paul
Published: October 2003

An optical diagnostic procedure based on laser-induced fluorescence was developed for direct in vivo cancer diagnosis without requiring biopsy. The methodology was applied in a clinical study involving over 100 patients in order to differentiate normal tissue from malignant tumors of the esophagus. Endogenous fluorescence of normal and malignant tissues was measured directly with the use of a fiber-optic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Detection of the fluorescence signal from the tissue was performed with the use of laser excitation. This report describes the differential normalized fluorescence (DNF) procedure using the amplified spectral differences between the normalized fluorescence of malignant tissue and normal mucosa. The results of this DNF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal tissue and malignant tumors for the samples investigated. Data related to various grades of Barrett's esophagus are discussed. The DNF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.
Use of Raman Spectroscopy for the Quantitative Analysis of Calcium Oxalate Hydrates: Application for the Analysis of Urinary Stones
Authors: Kontoyannis Christos G. , Bouropoulos Nicolaos Ch. , Koutsoukos Petros G.
Published: October 2003

The potential use of the Raman spectroscopy (RS) for the quantitative analysis of the mineral components of urinary stones consisting mainly of the mono- and dihydrate salts of calcium oxalate has been demonstrated. The quantitative analysis was based on the construction of calibration curves made of known mixtures of synthetically prepared pure calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD). The Raman spectra of well-mixed powdered samples of COM and COD were recorded, and the characteristic bands at 1462 and 1477 cm−1 for COM and COD, respectively, were used as the basis for the quantitative analysis. It was found that xM = ( IR – 0.134)/(0.8 IR + 1.52), where xM is the molar fraction of COM in the solid mixture and IR represents the intensity ratio of the Raman band at 1462 cm−1 to that of 1477 cm−1. The calibration curve was used for the analysis of a typical urinary stone surgically removed, and it was found that xM = 0.33. This finding was confirmed by infrared quantitative spectroscopic analysis. Quantitative analysis using the proposed Raman technique had a detection limit of approximately 0.6 mol % content in COM. The relative advantage of RS lies in its potential use as a nondestructive analytical technique for the mineral composition of urinary stones.
Fused-Silica-Aperture Thermospray Sample Introduction into Axially Viewed Inductively Coupled Plasma—Atomic Emission Spectrometry
Authors: Conver Timothy S. , Yang Jinfu , Koropchak John A. , Shkolnik Gerald , Flajnik-Rivera Christine
Published: October 2003

Axially viewed inductively coupled plasma–atomic emission spectrometry (ICP-AES) has encountered a resurgence in popularity over the past few years. It has been demonstrated that 5- to 10-fold improvements in limits of detection (LODs) can be obtained with axial viewing compared to conventional side-on-viewed ICP-AES. In this report, the coupling of fused-silica-aperture thermospray (FSApT)-based sample introduction with axially viewed ICP-AES is reported, in order to combine the properties of increased sample transport and reduced LODs for FSApT with the improved detection power of axially viewed ICP-AES. When FSApT was used with the standard axial torch having a large-diameter (2.3-mm) injector, high signal and background relative standard deviations (RSDs) resulted, as compared to results for pneumatic nebulization, limiting the LOD improvements obtained with FSApT. Smaller injectors (0.8-mm and 1.5-mm i.d.) allowed RSDs for FSApT that were similar to pneumatic sample introduction levels, and larger LOD improvements (10×) resulted. Data for FSApT with axially viewed ICP-AES were also compared with data for FSApT with side-on-viewed ICP-AES, and axial viewing averaged an improvement of only a factor of 2. This small level of improvement suggests that the optical system for the axial system is not optimized for use with high-performance sample introduction. On the basis of improvement factors for FSApT with side-on viewing, FSApT with axially viewed ICP-AES averages LODs that are about 73 times better than those for the conventional side-on-viewed ICP-AES with pneumatic nebulization.
Novel Environmental Control Chamber for FT-Raman Spectroscopy: Study of in situ Phase Change of Sulfur
Authors: Edwards H. G. M. , Farwell D. W. , Turner J. M. C. , Williams A. C.
Published: October 2003

The adaptation and construction of an environmental chamber suitable for FT-Raman spectroscopy is described for the recording of Raman spectra of specimens at temperatures from 25 to 125 °C while exposed to different controlled synthetic atmospheric conditions. Test spectra were obtained from sulfur to illustrate the stability and applications of the system. The α rhombic/β monoclinic phase change in sulfur was monitored as a function of time, and bands sensitive to this phase change have been identified.
Recovery of Digital Information Stored in Living Plant Leaf Photosynthetic Apparatus as Fluorescence Signals
Authors: Ning Li , Petersen Bent E. , Edwards Gerald E. , Daley Larry S. , Callis James B.
Published: October 2003

A CCD (charge-coupled device)-equipped, imaging spectroscopic instrument is discussed that can be reversible and rapidly reconfigured to image photosynthetic fluorescence, allowing two-dimensional spatial estimates of fluorescence quantum yield ( Y′). Y′ images of leaf areas with immediately functional photosynthetic apparatus appear smooth and uniform and are much less affected by variations in chlorophyll content and light path through the leaf. However, areas of the leaf where the photosynthetic apparatus has different light history, pathology, or other damage generate different Y′ value images. This characteristic allowed storage and recovery of images from leaves. Extending this finding, we prepared binary data coding for the value of π to 99 decimal places (100 digits), on living leaves. The images containing the binary codes for these digits can be “read” by eye, because the human brain interprets visual data with great skill. However, it was necessary to enhance the images to facilitate instrument “reading”. A program was developed to enhance the images and “read” the data images with no errors. The photosynthetic mechanism involved (nonphotochemical quenching), the role of leaf age and germplasm variation, and the potential applications of this finding in terms of bioelectronics are discussed.
Improved Infrared Spectroscopic Method for the Measurement of 13C: 12C Ratios
Authors: Kindness Andrew , Marr Iain L.
Published: October 2003

Pressure broadening of an infrared absorption band of gaseous CO2 makes measurement of a band intensity very much easier and also much more precise in comparison with the results obtained by measuring the intensity of a single line in a gas-phase spectrum. The isotopic shift of the v3 bands for carbon dioxide centered at 2350 cm−1 is sufficient to completely separate the P branch for 13CO2 from the two branches for 12CO2. The intensity ratios can be measured accurately on a low-resolution FT-IR spectrometer when the CO2 is pressurized to 10 bar (106N m−2) with N2, permitting isotope ratio differences as small as 0.02 atom % above the natural abundance of 1.11 atom % to be detected.
Quantitative Analysis of Aluminum Impurities in Zinc Alloy by Laser-Induced Breakdown Spectroscopy
Authors: Kim D. E. , Yoo K. J. , Park H. K. , Oh K. J. , Kim D. W.
Published: October 2003

Laser-induced breakdown spectroscopy has been employed for the spectroscopic study of a laser-produced Zn alloy plasma for the analysis of Al impurities in Zn alloy. The laser-produced Zn alloy plasma was generated by a pulsed Nd:YAG laser (105 mJ, 3 ns). The physical characteristics of the laser-produced Zn alloy plasmas and an optimum condition for the composition analysis are reported. With the use of the relative intensities of spectral emission lines from standard samples, calibration curves for the analysis of aluminum in Zn samples were obtained in the case of air, vacuum, and Ar environments.
T1 Relaxation of Perylene in Fluid Ethane: Pressure-Dependent Changes in Short-Range Organization
Authors: Heitz M. P. , Horne J. C. , Blanchard G. J. , Bright F. V.
Published: October 2003

We report our measurements of vibrational population relaxation of the v7 (1375 cm−1) mode of perylene in ethane at a series of fluid pressures. The data show that T1 decreases with increasing fluid pressure and that the dependence of T1 on pressure is not consistent with predictions based on simple spatial or stoichiometric considerations. The data indicate a nonrandom orientational distribution of the solvent molecules about the solute where the portion of the solvent environment sensed by the perylene v1 coordinate changes from one ordered state to another ordered state with increasing pressure.