bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Treatment of UV Resonance Raman Spectra of Biological Molecules: Application to the Study of Membrane-Bound Proteins
Authors: Efremov Roman G. , Feofanov Alexey V. , Nabiev Igor R.
Published: July 2005

A set of instrumental and digital signal processing techniques (Fourier self-deconvolution and the maximum entropy method) was adopted to detect and treat low-signal-level UV resonance Raman spectra of biological molecules and supramolecular complexes. The applicability of the methods for analysis of ATP binding in the active site of Na+,K+-ATPase, as well as for investigation of aromatic amino acids involved in the functioning of bacterial and visual rhodopsins, is demonstrated.
GC/MS and FT-IR Spectra of Methoxymethanol
Authors: Johnson R. A. , Stanley A. E.
Published: July 2005

In the course of recent investigations of the laser-induced reactions of the alkyl alcohols, irradiations of methanol in the gas phase with a carbon dioxide (infrared) laser produced very interesting results. The principal product of the reaction, formaldehyde, spontaneously reacted with excess methanol to form methoxymethanol, a molecule about which very little is known. Initially, due to the presence of excess reactant still in the sample cell, the infrared spectra displayed the bands of the mixtures of both methanol and methoxymethanol, enabling this laboratory to report only the combined infrared spectra with three infrared bands assigned to methoxymethanol. Additional research utilizing hyphenated chromatographic/spectroscopic techniques significantly advanced this effort. A gas chromatograph interfaced with a mass selective detector (GC/MS) and another gas chromatograph interfaced to a gold-plated lightpipe (GC/FT-IR) enabled the recording of both mass and infrared spectra, respectively. After extensive and innovative research efforts, which included the use of novel subambient temperature lightpipe studies, this laboratory recorded the infrared spectra of isolated methoxymethanol, a scientific first. Research in this area is ongoing. This paper reports the experimental parameters and techniques as well as infrared and mass spectra of all molecules investigated, including methoxymethanol, formaldehyde, and methanol, including one deuterated species.
Sample Transfer Technique for Thin-Layer Chromatography/Fourier Transform Infrared Spectrometry
Authors: Yamamoto H. , Wada K. , Tajima T. , Ichimura K.
Published: July 2005

A simple and convenient procedure for the transfer of separated zones from a thin-layer chromatographic (TLC) sheet to a powder layer of potassium bromide is described. The pattern of the zones separated in two dimensions on a TLC sheet is preserved during transfer; therefore, an infrared (IR) chromatogram corresponding to the original TLC pattern and an IR spectrum for each separated zone are easily recorded by diffuse reflectance Fourier transform IR spectrometry. The transfer process requires only 2 min, and the TLC sheet can be placed directly into the diffuse reflectance accessory of the spectrometer, which prevents sample loss and shortens data collection time. The limit of detection for anhydrous caffeine was 2 μg.
Apparent Bias in the X-Ray Fluorescence Determination of Titanium in Selected NIST SRM Low-Alloy Steels
Authors: Pella P. A. , Marinenko R. B. , Norris J. A. , Marlow A.
Published: July 2005

X-ray fluorescence results of the analysis of titanium in NIST SRM 1165 and 1264 low-alloy steels were found to be significantly different from the certified values. These differences appear to be unique to the XRF results since results from other methods such as emission spectroscopy did not show any discrepancies. The microhomogeneity of selected samples was examined by electron probe microanalysis and revealed the presence of titanium inclusions containing varying amounts of zirconium, niobium, and tantalum. Differences in metallurgical uniformity are believed to be the major cause of apparent XRF bias in these SRMs. XRF analysis of the new 1760-series alloys indicates that these are more uniform and more accurate for purposes of calibration than the 1160 series and 1260 series for elements such as titanium.
A Quantum-Statistical Method for the Determination of Vertical Temperature Profiles in the ICP
Authors: Curry D. L. , Fannin H. B.
Published: July 2005

A method for the determination of vertical temperature profiles in the ICP utilizing Fermi-Dirac statistics to describe the relative population of excited neutral states of argon is presented. This method allows for calculation of temperature relative to a single position in the plasma, or absolute temperature profiles if the temperature is known at a single position.
ChaRacterization of Carbon-Filled Polymers by Specular Reflectance
Authors: Claybourn M. , Colombel P. , Chalmers J.
Published: July 2005

Carbon-filled polymers, due to their opacity, are normally difficult to characterize by IR spectroscopy. We describe a method for obtaining spectra based on a specular reflectance measurement at normal incidence using the IR microscope. Peaks in the specular reflectance spectrum have a derivative-like shape due to refractive index dispersion. After application of the Kramers-Kronig transformation, an absorption index spectrum is obtained; this has a more conventional appearance and is thus much easier to interpret. The technique was found to be applicable so long as certain criteria were met, such as optical flatness and no contributing reflectance effects from the subsurface. Various polymeric materials were examined which contained carbon in the range 2 to 25% w/w. This approach was found unsuitable for carbon-fiber/polymer composites which show predominantly diffuse reflectance due to scattering at the surface features.
Recognition of Mass Spectral Interferences in Inductively Coupled Plasma-Mass Spectrometry
Authors: Shao Youbin , Horlick Gary
Published: July 2005

Spectral-interference problems in inductively coupled plasma-mass spectrometry (ICP-MS) can be recognized by making analytical determinations at more than one mass for elements that have more than one naturally occurring isotope. If the results for the isotopes do not agree, then a spectral-interference problem is often indicated. A powerful tool that can be used to pinpoint the source of spectral interference is to compare results (even for mono-isotopic elements) and result discrepancies, sample-by-sample, with the sample composition of the suspected sources of the spectral interferent. This can be effectively carried out with the use of computer-generated bar graphs. The major elements in a sample are frequently the source of species that cause spectral-interference problems. The concentrations of the major elements in a sample may, in some cases, be more readily determined by ICP-atomic emission spectrometry (ICP-AES). When ICP-AES results for major components in a set of samples are compared to ICP-MS results of the minor components in the same set of samples, spectral interferences may be revealed. The application of this approach to the identification of spectral interferences is illustrated for the determination of Ba, Zn, Cu, and Ni in a set of ground-water samples.
A Simple Device for Studying FT-IR Emission Spectra of Solid Surfaces
Authors: Rewick Robert T. , Messerschmidt Robert G.
Published: July 2005

We have designed and tested a spectral infrared emissivity device (SIRED) for studying the FT-IR emission spectra of solid surfaces. The cell, which is commercially available, can be used from near room temperature to 400°C. Emissivity results obtained by SIRED for several common laboratory samples compare well to published values for similar materials. As an example of another measurement using SIRED, we show results for the evaluation of the plasma wavelength of a semiconductor.
A Color Analysis of the Brancacci Chapel Frescoes
Authors: Bacci M. , Baldini F. , Carlà R. , Linari R.
Published: July 2005

About one hundred significant spots (area = 0.5 cm2) that were homogeneously colored were selected on the frescoes “Resurrection of the son of Teofilo,” “Saint Peter in pulpit,” and “Saint Peter heals invalids by his shadow” in the Brancacci Chapel (Chiesa del Carmine, Florence). The reflectance spectra of these spots were recorded before and after restoration with the use of an external integrating sphere, which was connected through optical fibers to a UV/visible spectrophotometer, and the data were stored in a personal computer. Spectrophotometric investigations were also performed on small samples of frescoes, which were appropriately prepared, in a laboratory, with pure pigments. The results we obtained are discussed in the light of our main purposes: (1) to achieve nondestructive identification of pigments; (2) to help create time-unalterable color archives; (3) to establish a method for monitoring eventual color changes; and finally (4) to obtain useful information for the fields of art restoration and art history.
Application of Step-Scan Interferometry to Two-Dimensional Fourier Transform Infrared (2D FT-IR) Correlation Spectroscopy
Authors: Palmer Richard A. , Manning Christopher J. , Chao James L. , Noda Isao , Dowrey Anthony E. , Marcott Curtis
Published: July 2005

The application of step-scan interferometry to two-dimensional infrared (2D IR) spectroscopy is described. In this 2D FT-IR experiment, a step-scan interferometer is used to study a system undergoing dynamic changes induced by an external perturbation. Because step-scanning removes the spectral multiplexing from the temporal domain, the time dependence of the sample response to the perturbation can be retrieved more conveniently, in comparison to conventional rapid-scan techniques. Time-resolved IR data are then converted to 2D IR correlation spectra. Peaks located on a 2D spectral plane provide information about interactions among various functional groups associated with the IR bands. In the step-scan mode, the FT-IR multiplex advantage is retained; thus, spectral regions far removed from each other can be correlated with the use of 2D analysis from a single scan. 2D FT-IR spectra for a composite film of isotactic polypropylene and poly( γ-benzyl-L-glutamate) subjected to a small-amplitude sinusoidal strain are presented. The 2D FT-IR spectra clearly differentiate bands arising from the polyolefin and polypeptide. Overlapped bands are deconvoluted into individual components on the 2D spectral plane due to their different dynamic behavior. The applicability of step-scan 2D FT-IR to a variety of dynamic experiments is discussed.
Deconvolution and Curve-Fitting in the Analysis of Complex Spectra: The CH Stretching Region in Infrared Spectra of Coal
Authors: Friesen W. I. , Michaelian K. H.
Published: July 2005

Numerical techniques are widely used to analyze spectra comprising overlapping bands. In principle, curve-fitting yields the most information, provided that the assumptions concerning the number of bands and their shapes are valid. Deconvolution is an effective means of estimating the number of bands and their positions, but this method is sensitive to noise and can produce spurious features which may be misinterpreted as being genuine. In this paper, we have combined curve-fitting with a nonlinear deconvolution technique to examine the CH stretching region of the infrared spectra of two different coal samples. The probable number of bands and their approximate frequencies were obtained by deconvolution of the measured spectra and then used in the fitting calculation. In order to choose between band shapes yielding fits of comparable quality, the fitted spectra were deconvolved and the results compared with the deconvolution of the original spectra. The samples analyzed were a Western Canadian vitrinite (separated coal maceral) and a lignite (low-rank coal). We conclude that the CH region of the photoacoustic spectrum of the vitrinite contents of twelve Voigt bands, while the diffuse reflectance spectrum of lignite is made up of ten Gaussian bands.
A Modified Phase-Modulation Spectrofluorometer for Lifetime-Resolved Fluorescence-Detected Circular Dichroism
Authors: Wu Karen , McGown Linda B.
Published: July 2005

The first demonstration of lifetime resolution in fluorescence-detected circular dichroism (FDCD) is described, performed on a modified phase-modulation spectrofluorometer in which a Babinet-Soleil compensator is used to generate the circularly polarized excitation. Measurements of optically inactive solutions indicate the absence of significant instrumental or optical artifacts for steady-state and lifetime-resolved FDCD. Advantages of the instrumental approach are discussed and early results are presented for a system of benzo(a)pyrene and benzo(k)fluoranthene in γ-cyclodextrin, demonstrating the accuracy of the lifetime determinations with circularly polarized excitation as well as the applicability of lifetime-resolved FDCD for studies of induced chirality in asymmetric microenvironments.
Rotational Temperature Estimation of CO at High Temperatures by Graphical Methods Using FT-IR Spectrometry
Authors: McNesby K. L. , Fifer R. A.
Published: July 2005

Rotational temperatures are obtained from gas-phase Fourier transformed infrared spectra of CO with the use of graphical methods over the temperature range 302 to 773 K. Peak absorbances of individual rovibrational transitions are corrected for instrumental distortion and are then fit to a Boltzmann distribution to obtain the rotational temperature of the gas. A solution to the convolution integral for FT-IR spectrometry is obtained by numerical integration. The equation relating observed peak absorbance, Aobs, to true peak absorbance, Apm, ranging from one to five true peak absorbance units for triangularly apodized spectra is:

[Formula: see text]

where the resolution parameter, ρ, is equal to 1/(2Δ γm), γm is the half-width at half-height (HWHH) of the absorption line in question, and Δ is the maximum optical retardation of the interferometer (here equal to 1 cm). In all cases, temperatures obtained by graphical analysis yielded gas temperatures within 10% of the actual temperatures. Experiments were also conducted to determine the CO rotational temperature in a premixed, low-pressure (64 Torr) CH4/N2O flame. CO temperatures for the premixed flame ranged from 1500 to 1700 K, indicating a large transferral of heat from the flame to the burner chamber.
Comparison of Electron and Infrared Spectroscopy with Thermal Analysis to Study Molecular Weight Effects in PVC-PMMA Blends
Authors: Burkhardt Cindy A. , Gardella Joseph A.
Published: July 2005

The effects of homopolymer molecular weight on the miscibility of PVC/PMMA solvent cast blends were studied. Two significantly different molecular weights were chosen for each of the homopolymers, and a series of blends was prepared from the four possible homopolymer-homopolymer combinations. Angle-dependent ESCA results suggest that the surfaces of the blends are enriched with PMMA. The extent of this enrichment is dependent on molecular weight, with the most enrichment seen in blends containing the lower-molecular-weight PMMA homopolymer. Differential scanning calorimetry (DSC) results are also presented.
Forensic Analysis of Acrylic Copolymer Fibers by Infrared Microscopy
Authors: Tungol Mary W. , Bartick Edward G. , Montaser Akbar
Published: July 2005

Ratios of absorbance peak areas ( AC=O/ AC=N) of carbonyl and nitrile groups were obtained for single acrylic fibers by IR microscopy. The precision of the comonomer ratios was evaluated for potential application in forensic fiber examinations. Precise (RSDs less than 0.4%) results for repetitive analyses of one location on a fiber were obtained. Precision was reduced when the cited ratio was measured at adjacent locations along the length of a single fiber. A further deterioration in precision was observed when different fiber specimens of the same type were analyzed. Analysis of different acrylic fiber specimens of the same type yielded RSDs which ranged from 2 to 6%. Fibers with diameters which ranged from 13 to 43 µm were examined. Precision was decreased for fibers with smaller diameters. Preliminary results indicate that acrylic fibers can differ by manufacturer as indicated by AC=O/ AC=N.
Chemical Sensor Based on an Artificial Receptor Element Trapped in a Porous Sol-Gel Glass Matrix
Authors: Narang Upvan , Dunbar Richard A. , Bright Frank V. , Prasad Paras N.
Published: July 2005

A synthetic organic receptor, dansyl-tethered β-cyclodextrin, is doped into an inorganic sol-gel matrix and spin cast as a film on fused-silica plates. The entrapped receptor exhibits changes in its fluorescence in the presence of borneol. Thus, this new material can be used as a reversible sensor. Various aspects of a sol-gel matrix as a host for recognition molecules were explored. This system demonstrates the possibility of using artificial receptors and sol-gel porous glass films for chemical sensing purposes.
Quantitative Analysis of Sugar Solutions Using a Novel Fiber-Optic-Based Sapphire ATR Accessory
Authors: Kemsley E. K. , Wilson R. H. , Poulter G. , Day L. L.
Published: July 2005

Quantitative analysis of sugar mixtures in solution is important in the soft drinks and brewing industries. Existing infrared sampling methods based on attenuated total reflectance (ATR) generally use crystal materials that do not have direct contact approval in food process environments. Sapphire is an attractive alternative, being hard, inert, and nontoxic. This work discloses a novel sapphire ATR crystal, built into a stainless steel-housed fiber-optic probe, suitable for use in a food production environment. The probe has been used to perform quantitative analysis of sucrose, glucose, and fructose mixtures in solutions, with the use of principal components regression (PCR) as the calibration method, and internal cross-validation to assess the predictive ability. Good prediction results were obtained.
Rare-Earth-Doped Glass Fiber for Background Rejection in Remote Fiber-Optic Raman Probes: Theory and Analysis of Holmium-Bearing Glass
Authors: Cooney Thomas F. , Schoen Christian L. , Sharma Shiv K. , Carey David M.
Published: July 2005

We have investigated the feasibility of using rare-earth-doped glasses in “self-filtering” optical fibers used for remote Raman spectral collection. We have derived a theoretical treatment and have used the measured relevant sample and glass parameters (e.g., optical absorption of the doped glass and ratio of the intensities of inelastic scattering to elastic scattering plus reflection) to evaluate the usefulness of such fibers. With the use of these parameters, the optical absorption bands of Ho-doped glass, in particular, are found to be sufficiently intense and sharp to enable this glass to be used in the collection fiber of a remote Raman probe. Ho-doped glass fiber of as little as 2 cm in length is sufficient to filter undesirable laser radiation while permitting a high proportion of the sample Raman signal to pass. Use of the 488.0-nm Ar+ laser line or green or red laser wavelengths from a “tunable” laser can ensure that the excitation is within an absorption band and close to the long-wavelength transmission cut-on for the doped glass.
Improvements in Methods for Spectral Combination of Gas Chromatography/Fourier Transform Infrared Spectroscopic Data
Authors: Haaland David M. , Thomas Edward V. , Blair Dianna S.
Published: July 2005

Coaddition of spectra in a single-component peak of a gas Chromatograph (GC) obtained with a Fourier transform infrared spectrometer is the method generally used to improve the signal-to-noise ratio (S/N) of the spectrum of the eluted analyte. It is commonly thought that coaddition of spectra to a relative intensity level of 40% of the GC peak will lead to the optimal improvement in S/N of the resulting composite spectrum. We have shown that this is not generally the case for either simulated Gaussian-shaped or experimentally obtained asymmetric GC bands. The optimal intensity level for coaddition is found to be a function of the shape of the GC band and the ratio of the number of background to sample scans used in generating the individual IR spectra. We have also introduced the use of classical least-squares (CLS) techniques as a superior method to improve the S/N of the composite analyte spectrum. With the use of CLS methods, spectra included in generating the composite spectrum can be a small fraction of the maximum intensity in the GC peak while still resulting in S/N improvements. The theoretical S/N of the composite spectrum with the use of CLS methods is shown to be always as good as or better than that achieved with the coaddition method. The improvements achieved in S/N when CLS methods are used can be more than a factor of two greater than results for the traditional coaddition method for the cases considered in this paper. Furthermore, it is shown that increasing the number of background to sample scans is a very convenient method to improve the S/N of the composite spectrum obtained by either method. The results presented here for GC/FT-IR are also generally applicable to LC/FT-IR, SFC/FT-IR, and TGA/FT-IR for bands that contain a single analyte.
Simultaneous Determination of Molecular Orientation and Surface Concentration in Anisotropic Monolayers on Liquid Substrates
Authors: Tung Yei-Shin , Gao Tao , Rosen Milton J. , Valentini Jose E. , Fina Leslie J.
Published: July 2005

A new method is developed for the simultaneous determination of chain orientation and surface concentration in monolayers on liquid substrates. The method is based on the use of s- and p-polarized reflection-absorption (RA) infrared intensities in conjunction with an optical model that includes anisotropy in the optical constants. The advantages and limitations of the method are explored in detail. A modeling assessment of the RA p/RA s ratio leads to information on how the ratio can be used to qualitatively interpret RA spectra. Spectral simulations are given that address the issues of frequency shifting and band distortion in reflection-absorption due solely to optical considerations. Experimental spectra of sodium dodecyl sulfonate are collected as soluble monolayers at the air/water interface. The spectral intensities are used to calculate the chain orientation, the surface concentration, and the associated errors. The surface concentration is compared with that predicted from surface tension isotherms.
Shifting of -OH Absorption Bands on NIR Spectra of Esters
Authors: Hansen Wei G.
Published: July 2005

The hydroxyl value is an indicator for the stages of esterification reaction. Instead of the wet chemistry titration method, the near-infrared (NIR) spectroscopic technique was utilized to monitor the hydroxyl values during the reaction. Because of the various raw materials and reaction conditions, the shifting of the -OH absorption band in the NIR spectra of esters was observed. The molecular structure, the reaction environment, and the state of the -OH groups are the most likely parameters responsible for the shifting of the -OH band.
TEA CO2 Laser-Induced Plasma with a Plane Shock Wave Structure
Authors: Kagawa K. , Tani M. , Ueda H. , Sasaki M. , Mizukami K.
Published: July 2005

A TEA CO2 laser beam (500 mJ, 100 ns) has been focused on a Zn target at reduced ambient gas pressures. In order to confine the laser plasma into a limited space, a tube (7 × 7 × 20 mm) has been placed just in front of the target, and the laser beam has been focused through the tube on the target. The time-resolved spatial distributions of Zn emission lines show that emission intensity increases quickly with a distinct jump near the front of the plasma and that the emissions take place only in a limited thin layer. It is also shown that the displacement of the emission front is proportional to 0.6 power of time. These experimental results support the supposition that the plasma is excited by a plane shock wave induced by the laser bombardment. This laser plasma confinement technique shows the possibility of improving the sensitivity in laser microprobe spectrochemical analysis.
Characterization and Application of an Infrared Linear Array Spectrometer for Time-Resolved Infrared Spectroscopy
Authors: Alawi Sadiq M. , Krug Teresa , Richardson Hugh H.
Published: July 2005

An infrared spectrometer is described which uses a 32-element InSb linear array detector. The infrared linear array (IRLA) spectrometer collects infrared spectra with a spectral width of 0.50 µm every 16 µs. The performance of the IRLA spectrometer is characterized with respect to signal-to-noise ratio, spectral resolution, time resolution, and instrumental line shape. The IRLA spectrometer is used to collect the time-resolved infrared spectra following 193-nm irradiation of a solution of Mo(CO)6 in hexane.
Polarized Raman Spectra from Some Sol-Gel Precursors and Micro-Raman Study of One Selected Copolymer
Authors: Posset U. , Lankers M. , Kiefer W. , Steins H. , Schottner G.
Published: July 2005

The polarized Raman spectra of γ-substituted propyl-trialkoxysilanes [Formula: see text] have been recorded, and an assignment is proposed. The spectra are briefly discussed with emphasis on the glycidoxy compound (IV). Micro-Raman data are also given for the co-condensation product of a 5:95 mixture of III and IV. The copolymer spectrum is compared to the precursor spectrum to show the effect of condensation on some selected vibrational bands. No bands for residual, noncondensed Si-OH groups are found in the polymer spectrum from which condensation to a three-dimensional network can be assumed to a high degree. The epoxy ring-breathing vibrational band indicates the ring to be cleaved only to a minor extent by reaction with the base catalyst.
Approach for Increased Information from the Second-Derivative Spectra in UV-Vis Absorption Spectroscopy
Authors: Antonov Liudmil , Stoyanov Stefan
Published: July 2005

The resolution of overlapping bands in the UV-Vis absorption spectra leading to determination of their basic parameters ([Formula: see text]) provides important information about the energies and probabilities of the electronic transitions. In the analysis of UV-Vis absorption spectra recorded linearly in wavelength by means of modern spectrophotometers with holographic gratings, the analytical shape describing individual bands is asymmetric. This factor leads to certain limitations in determining their number with the use of the second-derivative spectra and decreased effectiveness of the computing procedure. It was found that the loss of information in d2 A/dλ2 is due to its long-wavelength attenuation in comparison with d2 A/dν˜2. An analytical equation connecting d2 A/dλ2 with d2 A/dν˜2 is proposed, which restores the information from the second derivative in the long-wavelength region.
Fluorometry of Carcinogenic Polycyclic Aromatic Hydrocarbons in Biological Systems
Authors: Song Ruixia , Li Kuang-Pang
Published: July 2005

Benzo(a)pyrene (BP) in liposomes and microsomes exhibits overlapping excimer bands peaked at 495 and 520 nm, respectively, in contrast to the single band of pyrene at 480 nm. Since BP is asymmetrical and pyrene is symmetrical, the dual maxima imply that the BP molecules in the excimer must be oriented either parallel or anti-parallel to each other. Time-resolved studies of BP oxidation by cytochrome P-450 show that the 520-nm component dissipates much faster than the 495-nm component during the first 30 min of metabolism, indicating that the initial P-450-BP interaction may be BP orientation sensitive. The binding of BP to the porphyrin group of a heme protein (e.g., hemoglobin or myoglobin) appears to be stronger under oxygen saturation than under CO2 saturation conditions. The transfer of BP between the membrane and the porphyrin group, as measured by means of excimer/monomer ratios, appears to be significantly different from that of pyrene. As the liposome-to-protein ratio increases, the excimer/monomer of BP steadily decreases, whereas that of pyrene increases and reaches a plateau. The significance of this phenomenon in their mechanisms of metabolism will have to be investigated further.
Infrared Hollow Waveguides for Capillary Flow Cells
Authors: Sato S. , Saito M. , Miyagi M.
Published: July 2005

Infrared hollow waveguides were studied for use as a capillary flow cell in spectroscopic gas sensing. Explosive gases (CH4, C4H10) were detected successfully by using a ZnS-coated Ag hollow waveguide, which has a high transmittance over a wide infrared spectral region. The response time was reduced to 0.1 s owing to the decrease in the cell volume. Pollution gases (SO2, NO2) were measured by a glass hollow waveguide, which is durable for such corrosive gases. By using these hollow waveguides, we can extend the optical pathlength easily, and consequently we can expect enhancement of the sensitivity.
Reflectance Spectra and Color of Potassium and Silver Chromates in Various Matrices
Authors: Tłaczała T. , Cieślak-Golonka M. , Bartecki A. , Raczko M.
Published: July 2005

The matrix influence on the diffuse reflectance spectra of K2CrO4 and Ag2CrO4 has been studied spectroscopically and colorimetrically. Oxide matrices (MgO, BaO, Li2CO3) were found to be inert towards the studied compounds. In halide matrices, the symmetry decrease of the tetrahedral CrO42− ion was observed through the appearance of the symmetry-forbidden transitions and intensity reversal. A bathochromic shift of the bands, in comparison to the results for K2CrO4, was found in the Ag2CrO4/Ag2SO4 system. It is explained under the assumption of strong cationanion interaction in the latter. On the basis of the color parameters, the halide matrices can be ordered according to their inertness towards K2CrO4. The quantitative relationship between the matrix effect and the molecular size of the host lattice components is given for K2CrO4.
Quantitative, Depth-Resolved Imaging of Oxygen Concentration by Phosphorescence Lifetime Measurement
Authors: Plant Randall L. , Burns David H.
Published: July 2005

Minimally invasive determination of oxygen concentration can be made by measuring phosphorescence lifetime. We describe a technique for depth-resolved measurements of oxygen concentration using confocal imaging of phosphorescence lifetime. A confocal imaging system is used to obtain depth-resolved measurements of phosphorescence decay. The spatial resolution of the system is characterized in terms of the Line Spread Function and shown to be similar in both lateral and depth directions. Lifetimes are calculated with the use of the Rapid Lifetime Determination technique. One- and two-dimensional quantitative images of oxygen concentration in a test specimen are rapidly generated from luminescence decay data. Measurements are made for oxygen concentrations ranging from 2 to 90 µM. A linear relationship between Pdmeso-tetra-(4-sulfonato-phenyl)-porphine phosphorescence inverse lifetime and oxygen concentration is determined. The presence of an intervening solution of different oxygen concentration does not significantly affect the concentration measurements made with the use of depth-resolved imaging techniques.
Shift of Mode-Hopping Wavelength in Single-Mode Semiconductor Lasers
Authors: Chien Ring-Ling
Published: July 2005

The shifts of the wavelength position that a radiation mode jumps from one longitudinal mode to the next in semiconductor lasers have been studied. The variation of the gain curve is found to depend not only on the junction temperature but also on the carrier density. The mode hops occur at different wavelengths and temperatures as the injection current changes. A systematic approach to controlling the temperature and current could extend the wavelength tuning range to a much greater extent. A wider tuning range will provide a free-running diode laser capable of readily reaching the specific atomic or molecular transition.
Variability of Steady-State Bacterial Fluorescence with Respect to Growth Conditions
Authors: Bronk Burt V. , Reinisch Lou
Published: July 2005

The UV-excited (∼280 nm) fluorescence emission spectra from suspensions of several different species of bacteria are examined to determine to what extent differences in condition of growth change their spectra. This is an important factor if these spectra are considered for use for identification of species. It was found that the spectra were relatively invariant with respect to whether the bacteria were harvested during growth (log phase) or after the medium was depleted (stationary phase). For a given strain of Escherichia coli it was found that the emission spectrum did not change for growth in rich, compared to minimal, medium; however, there was some change for other species. For bacterial spores, the emission spectra were found to be similar for several species. An estimate was made for the quantum yield for Bacillus megaterium spores. The emission spectrum from spores and bacteria was found to change substantially on drying.
Selective UV Resonance Raman Excitation of Vinyl Group Vibrations in an Isomer of Crotyl Chloride
Authors: Chadha S. , Nelson W. H. , Emrich R. , Lindesmith E.
Published: July 2005

The Raman spectra of cis, trans, and vinyl isomers of crotyl chloride (i.e., cis and trans 1-chloro-2-butene, and 3-chloro-1-butene) have been excited at 218 nm and at 231 nm. With 218-nm excitation the ethylenic mode belonging to the vinyl isomer is only modestly preresonance enhanced. On the other hand, the preresonance enhancement of the peaks belonging to the cis and trans isomers is very noticeable and nearly identical in energy to the peaks of cis and trans polybutadiene, which occur at 1655 and 1665 cm−1, respectively. However, with 231-nm excitation the vinyl-isomer ethylenic mode at 1633 cm−1 is very strongly enhanced, while the cis and trans isomer modes show no corresponding enhancement, but appear to decrease in relative intensity. Responsibility for the strong vinyl group enhancement is assigned to an electronic transition observed as a broad shoulder near 230 nm. By exciting at 231 nm it is possible to detect small amounts of the vinyl isomer in the presence of cis and trans crotyl chloride. Remarkably strong enhancement under 231-nm excitation has been noted as well for the first overtone of the vinyl ethylenic mode observed at 3263 cm−1.
IR and NMR Correlations for 3-x and 4-x Substituted Anilines
Authors: Nyquist R. A.
Published: July 2005

Infrared (IR) and/or Nuclear Magnetic Resonance (NMR) carbon-13 data are presented for 3- x and 4- x substituted anilines. Correlations are presented for the δ13C-1 chemical shift vs. Hammett δ p and δ m values, vasym., NH2 vs. δ13C-1, vsym. NH2 vs. δ13C-1, δ13C-1 vs. vasym. NH2, δ13C-1 vs. the absorbance ratio A( vasym. NH2/ A( vsym. NH2), and δ13C-l vs. Taft δ R°. The IR data for these compounds are recorded in the vapor phase, and in hexane, carbon tetrachloride, and chloroform solutions. The NMR chemical shift data for these compounds in solution with chloroform were obtained with the use of tetramethylsilane as the δ13C resonance reference frequency.
On the Phase Match in Multiplex CARS of Condensed Media
Authors: Kircheva P. P. , Hadjichristov G. B.
Published: July 2005

The phase-matching conditions in condensed-media multiplex CARS are analyzed for the case where a spectral region is recorded according to variation of the pump frequency. The possibility of eliminating the influence of the phase mismatch on the recorded CARS spectra and of experimentally evaluating the third-order electronic susceptibility tensor is discussed.
Rapid Recovery of Wide-Bandwidth Photothermal Signals via Homodyne Photothermal Spectrometry: Theory and Methodology
Authors: Power J. F. , Prystay M. C.
Published: July 2005

Homodyne photothermal spectrometry (HPS) is a very wide bandwidth signal recovery technique which uses many of the elements of lock-in detection at very low cost. The method uses a frequency sweep, with a high-frequency bandwidth of up to 10 MHz, to excite a linear photothermal system. The response sweep of the photothermal system is downshifted into a bandwidth of a few kilohertz by means of in-phase mixing with the excitation sweep with the use of a four-quadrant double-balanced mixer and a low-pass filter. Under conditions derived from theory, the filter output gives a good approximation to the real part of the photothermal system's frequency response, dispersed as a function of time. From a recording of this signal, the frequency and impulse response of the photothermal system are rapidly recovered at very high resolution. The method has been tested with the use of laser photopyroelectric effect spectrometry and provides an inexpensive, convenient method for the recovery of high-frequency photothermal signals.
Quantitative Spectrographic Analysis for in Situ Continuous Emission Monitoring
Authors: Shlifshteyn Alex , Lang Fred D.
Published: July 2005

To determine the thermal efficiency and the effluent flow rates of fossil-fired boilers, Exergetic Systems has developed an in situ, dispersive interferometer. This Emissions Spectral Radiometer/Fuel Flow instrument (ESR/FF) can measure effluent concentrations with the high accuracies needed to make efficiency determinations and to meet environmental control requirements. This paper discusses the software algorithms developed to process the data from these instruments to provide accurate peak-to-peak normalization of measured absorbance data to HITRAN-generated data. After implementation of both signal-domain and frequency-domain normalization, the frequency-domain method was chosen because it was significantly faster to process. With the use of this analysis method and the pre-installation calibration method described herein, flue gas compounds are quantified with a sensitivity of 10 Δppm. This inexpensive and reliable instrument yields accurate quantitative analysis of flue gases for continuous emission monitoring (CEM) of fossil-fired boilers.
Use of Buffered Solvent Systems with Concentric Flow Nebulization Liquid Chromatography/Fourier Transform Infrared Spectrometry
Authors: Lange Andrew J. , Griffiths Peter R.
Published: July 2005

Identifiable Fourier transform infrared (FT-IR) spectra of species eluting from a high-performance liquid Chromatograph (HPLC) in buffered mobile phases are shown. The spectra are measured with the use of an online solvent-elimination HPLC/FT-IR interface based on direct-deposition concentric flow nebulization. Both volatile and nonvolatile buffers were used, in mobile phases consisting of 63–100% water. Examples of spectra of components separated by microbore HPLC using these buffered systems are shown. For the systems using nonvolatile buffers, spectral subtraction is needed to obtain analyte spectra, and absorption bands due to the buffer are rarely completely eliminated. For systems using volatile buffers, very little or no spectral subtraction is needed at low buffer concentrations. Minimum identifiable quantities in the low-nanogram range were achieved.
Optical Data of Rough-Surfaced Ceramics: Infrared Specular and Diffuse Reflectance versus Spectra Simulation
Authors: Hopfe V. , Korte E. H. , Klobes P. , Grählert W.
Published: July 2005

Infrared reflection of strongly absorbing as well as scattering samples was studied. The optical functions of sintered alumina ceramics were derived with the use of the Kramers-Kronig transformation to reconstruct the phase shift under the assumption of a semi-infinite sample with an ideal plane and, in any scale, a smooth surface. In order to validate this procedure and to optimize measuring parameters, the results were compared to their simulated counterparts. Starting from the dielectric functions of monocrystalline Al2O3, the optical response of the sample was calculated by taking into account the polycrystallinity of the bulk and the roughness of the surface; eventually the spectra of specular reflectance were simulated on this basis for different angles of incidence. It turned out that the comparably simple evaluation procedure is well suited in spite of the rough surface and is particularly reliable in the case of large angles of incidence whereby scattering is minimized. Some characteristics of this diffusely reflected component are discussed.
BMP-4 inhibits follicle-stimulating hormone secretion in ewe pituitary
Authors: Faure M-O , Nicol L , Fabre S , Fontaine J , Mohoric N , McNeilly A , Taragnat C
Published: July 2005

Activins and inhibins, members of the transforming growth factor-beta family are able to stimulate and inhibit, respectively, FSH synthesis and release. Other members of this superfamily, the bone morphogenetic proteins (BMPs), may also affect FSH synthesis in the mouse. The aim of this work was to determine whether BMPs are expressed in the ovine pituitary and whether they play a role in the regulation of FSH release.

The mRNAs encoding BMP-2, BMP-4, BMP-7 and the oocyte-derived growth factor, growth differentiation factor (GDF)-9 were detected in the pituitaries of cyclic ewes by reverse-transcriptase PCR, as well as the mRNAs encoding the BMP type I receptors, BMPR-IA (activin-receptor-like kinase (ALK)-3) and BMPR-IB (ALK-6), and type II receptors (BMPR-II). Immunolabeling of pituitary sections revealed the presence of BMPR-IA (ALK-3) and BMPR-II in gonadotrope cells. To investigate the potential effects of BMPs on FSH secretion, ewe pituitary cell cultures were treated with BMP-4 (10−11 M to 10−9 M) for 48 h. Interestingly, FSH release was decreased in a dose-dependent manner. At 10−9 M BMP-4 both FSH concentration and FSHβ mRNA expression were reduced by 40% of control values. In contrast, there was no inhibitory effect on either LH or LHβ mRNA expression. A similar result was found with BMP-6. BMP-4 triggered the phosphorylation of Smad1, suggesting that the effect of BMP-4 on FSH secretion is due to the activation of the BMPs signaling pathway. Furthermore, BMP-4 blocked the stimulatory effect of activin on both FSH release and FSHβ mRNA and amplified the suppression of FSH release and FSHβ mRNA levels induced by 17β-estradiol. These results indicate that a functional BMP system operates within the sheep pituitary, at least in vitro, to decrease FSH release and to modulate the effect of activin.
Effects of 5′-uridylic acid feeding on postprandial plasma concentrations of GH, insulin and metabolites in young calves
Authors: Katoh K , Yoshioka K , Hayashi H , Mashiko T , Yoshida M , Kobayashi Y , Obara Y
Published: July 2005

Postprandial changes in plasma concentrations of GH, insulin, IGF-I, leptin and metabolites were compared between young Holstein bull calves fed with milk alone (control group) and with milk+5′-uridylic acid (UMP) (UMP group). UMP (2 g/day) was given with milk at 0830 h and 1530 h for 11 days from the 4th to the 14th day after birth. The perirenal fat weight was significantly lower in the UMP group than in the control group, but there was no significant difference in the weights of the liver, spleen and heart between the groups. Basal GH concentrations in the UMP group were slightly higher, but the postprandial increase in plasma insulin level and the area under the curve for insulin in the UMP group were significantly lower than those in the control group. There was no significant difference in IGF-I levels between the groups. In addition, the postprandial glucose concentrations were lower in the UMP group as reflected by the insulin level, and nonesterified fatty acid concentrations were not different. In the muscle (M. longissimus thoracis) sampled at 14 days of age, the triacylglycerol (TAG) content was significantly greater but glycogen content was significantly lower in the UMP group than in the control group. From these results, we have concluded that feeding 5′-UMP at 2 g/day for 11 days significantly alters TAG accumulation in the body and plasma concentrations of GH and insulin in young bull calves.
Adipose tissue transplantation protects ob/ob mice from obesity, normalizes insulin sensitivity and restores fertility
Authors: Klebanov Simon , Astle Clinton M , DeSimone Olga , Ablamunits Vitaly , Harrison David E
Published: July 2005

Adipose tissue affects metabolism by secreting various adipokines. Lipodystropic mice benefit both from leptin replacement therapy and from transplantation of normal fat. Leptin-deficient Lepob/Lepob (ob/ob) mice can also be treated with leptin. Surprisingly, there have been no reports of successful treatment of obese ob/ob mice by transplantation of normal white adipose tissue (WAT). If WAT transplantation is ineffective in treating insulin resistance and diabetes in obese individuals, its applicability may be limited in humans as such abnormalities are usually associated with obesity. In the current study, we tested whether WAT transplantation might prevent, and even reverse, abnormalities characteristic of ob/ob mice. To assess the preventive potential, 6-week-old ob/ob mice were transplanted, subcutaneously, with gonadal fat pads from normal mice. Profound effects on multiple physiological phenotypes were achieved despite leptin levels below 25% of those in control mice. WAT from one donor reduced body weight gain, and WAT from 4 or 8 donors prevented obesity in ob/ob mice. Nonfasting insulin levels and insulin tolerance test were normalized. Corticosterone elevation was also prevented. Finally, WAT from 4 donors restored fertility in ob/ob females. The effects of WAT transplantation were long-lasting, with body weight gain suppressed for at least 40 weeks. To assess the therapeutic potential, obese 13-month-old ob/ob mice with a long history of leptin deficiency were used. Their body weight decreased by approximately 50% when transplanted with WAT from 8 donors. As in young recipients, transplantation greatly reduced nonfasting insulin, suggesting normalized insulin sensitivity. Thus, WAT transplantation was effective for both prevention and therapy. In the future, WAT transplantation may become a useful alternative to hormone replacement in treating not only lipodystropy, but also certain types of obesity.
State of the Art Pump Technology for Reverse Osmosis Systems
Authors: Schmitz R.
Published: July 2005

The industrial significance of diaphragm processes in mass separation is ever increasing; this is particularly true for the use of reverse osmosis (RO) and related methods. Decisive factors for the economy of RO processes, and thus for the future of this technology, are the reliability and energy consumption of the high‐pressure pumps involved. Current pump developments reflect clear progress in this field.
Genetic interaction between Wnt7a and Lrp6 during patterning of dorsal and posterior structures of the mouse limb
Authors: Adamska Maja , Billi Allison C. , Cheek Susannah , Meisler Miriam H.
Published: July 2005

The original article to which this Erratum refers was published in Developmental Dynamics 233:368–372Developmental Dynamics(2005) 233(2) 368–372