bluuebunny/crossref_metadata_2025 huggingface dataset:
Room-Temperature Luminescence of a Variety of Compounds on 1% α-Cyclodextrin/NaCl Mixture
Authors: Richmond Marsha D. , Hurtubise Robert J.
Published: June 2005

With the use of model compounds of widely different functionality, it was found that a 1% α-cyclodextrin/NaCl mixture could be used in place of an 80% α-cyclodextrin/NaCl mixture to obtain solid surface room-temperature fluorescence (RTF) and phosphorescence (RTP) data. Analytical figures of merit are reported for four compounds. The use of a smaller percentage of α-cyclodextrin results in lower cost; no loss of analytical integrity, compared with that for an 80% α-cyclodextrin/NaCl mixture; and easier handling of the α-cyclodextrin/NaCl mixtures.
Adaptive Signal Processing Techniques: An Application to Raman Spectroscopy
Authors: Jordan Ramiro , Dyer Stephen A.
Published: June 2005

In this study, the applicability of adaptive filters and algorithms to the enhancement of Raman spectra is investigated. The two adaptive-filter realizations described are the transversal (tapped-delay) and the lattice. The two adaptive algorithms considered are the least-mean-square and the modified least-square. Experimental results demonstrate that enhancement of Raman spectra obtained at low signal-to-noise ratios can be achieved. Extrapolation is applied to enhance the inherently low resolution of Raman spectra. Adaptive filtering techniques yield results comparable to those obtained from maximum-entropy methods for estimating spectra, with a resolution exceeding that allowed by Fourier procedures.
Glass Capillary Array Nebulizer for Atomic Spectrometry
Authors: Babis Jeffery S. , Kacsir Jerold M. , Denton M. Bonner
Published: June 2005

The nebulization of sample solution is a critical step in most atomic spectrometric methods. A novel nebulization technique, based on a glass capillary array, has been investigated. Basic operating parameters and characteristics have been studied to determine how this new nebulizer may be applied to atomic spectrometric methods. The results of preliminary comparisons with current pneumatic nebulizers as well as the porous glass frit nebulizer indicate several notable differences. The glass capillary array nebulizer has a high sample transport efficiency, and, in addition, the glass capillary array is not as limited in performance as the porous frit nebulizer in terms of sample equilibration time and the requirement for a wash cycle. The nebulizer shows great promise where sample volume is limited or where rapid response is necessary, as in chromatography or flow injection analysis.
Obliquely Crossed, Differential Thermal Lens Measurements under Conditions of High Background Absorbance
Authors: Erskine Steven R. , Bobbitt Donald R.
Published: June 2005

A differential thermal lens spectrometer based on the oblique crossing of separate pump and probe beams is described. This arrangement utilizes the differential response of the thermal lens to compensate for the intensity noise in the pump source while maintaining the intrinsic sensitivity of photothermal measurements. Thus, this design is ideally suited for absorbance measurements in the presence of a large background, such as might be encountered in circular dichroism or indirect photometry. The theory describing the thermal lens signal observed with this configuration will be developed and experimentally verified. The experimental conditions mandating differential TL measurements will also be investigated. Absorbance changes of 2 × 10−7 are demonstrated. Application of this arrangement to indirect HPLC detection is also discussed.
The Effects of Temperature on the Solid-Surface Luminescence Properties of Benzo(f)quinoline Adsorbed on Filter Paper
Authors: Ramasamy S. M. , Hurtubise R. J.
Published: June 2005

Experimental values of fluorescence quantum yield, phosphorescence quantum yield, and phosphorescence lifetime were acquired at temperatures from 23° to −180°C for the protonated form of benzo( f)quinoline adsorbed on filter paper. From the experimental values, triplet formation efficiencies, rate constants for phosphorescence, and rate constants for the radiationless transition from the triplet state were calculated. The results showed the various interrelationships of the solid-surface radiative and nonradiative processes. In addition, the results indicated that the modulus of the solid matrix is an important factor in enhancing phosphorescence quantum yield.
FT-IR Spectra of Water in Microporous KBr Pellets and Water's Desorption Kinetics
Authors: Malhotra V. M. , Jasty S. , Mu R.
Published: June 2005

The structure and spectra of water adsorbed on microporous (pore size <3 μm) KBr pellets were investigated, with the use of an infrared absorption technique at 220 < T < 450 K; P = 0.13 Pa, and differential scanning calorimetry (DSC) measurements at 100 < T < 320 K. In addition, water's overall desorption kinetics from KBr pellets were determined by isothermal runs at 330 < T < 400 K, P = 0.13 Pa by means of in situ transmission Fourier transform infrared (FT-IR) spectroscopy. The results suggest that KBr/water interaction is complex and that water is retained by pellets in three modes. In the first, water forms a monolayer around KBr particles in which hydrogens of water are held at the surface via bonding between hydrogen and Br− ions. This monolayer contains the dominant water in KBr pellets. In the second mode, small water clusters are trapped between the KBr particles and in micropores, and we believe that this type of water is trapped during pellet preparation. Additional water bands, observed at ∼3300 and ∼1670 cm−1, have been assigned to a coordinated type of water, near or at the surface, which constitutes a third type. DSC results indicate that none of the three types of water are capable of forming ice in KBr pellets. On increasing the water content in the pellets, additional water is adsorbed on the top of the monolayer type water, with the other two types being uneffected. The water's desorption kinetics data were tested for ten different decomposition models, and the results can best be described by a 3-dimensional diffusion desorption model, suggesting that micropores are blocked by KBr particles and/or that pores do not run across the width of the pellet.
Laser-Enhanced Ionization Detection in a Laser-Produced Plasma at Atmospheric Pressure: Theoretical and Experimental Considerations
Authors: Coche Marianne , Berthoud Thierry , Mauchien Patrick , Camus Pierre
Published: June 2005

The essential data of matter-laser interaction which govern the creation of the plasma are described and are shown to permit the determination of several plasma parameters. The choice of an electrical detection adapted to a continuous plasma under atmospheric pressure allows the study by analogy of the transient laser-produced plasma (LPP). Experimental results confirm that laser-enhanced ionization detection in an LPP at atmospheric pressure is not feasible because ionization is “strong” and collection is “weak.”
Resonance-Enhanced Multiphoton Ionization Jet Spectroscopy and Mass Spectrometry of Tyrosine-Containing Dipeptides Using a Pulsed Laser Desorption/Volatilization Method
Authors: Li Liang , Lubman David M.
Published: June 2005

Pulsed laser desorption is used as a means of volatilizing thermally labile tyrosine-containing dipeptides for entrainment into a supersonic jet expansion. The jet expansion provides ultracold molecules whose spectral features are probed by resonant two-photon ionization (R2PI) spectroscopy in a time-of-flight mass spectrometer. In the dipeptides studied, spectral contours ∼1.5 nm FWHM are observed. Although no sharp spectral features were obtained, the shape of the contour is quite distinctive, and isomeric dipeptides can be distinguished. In addition, the ions produced are monitored in a time-of-flight mass spectrometer. It is shown that soft ionization can be obtained for each of these dipeptides by optimizing the jet cooling and exciting at the maximum intensity of the specific origin transition. By an increase in the laser energy, fragmentation is produced which can be used for structural identification of each of these dipeptides. Other factors that may affect these results, such as thermal decomposition, are also investigated.
IR Spectroscopy of Polyperfluoroethylene Oxide Lubricants on Amorphous Carbon
Authors: Saperstein David D.
Published: June 2005

The FT-IR transmission spectrum of 30 Å of a polyperfluoroethylene oxide lubricant on amorphous carbon is shown to be proportional to the transmission spectrum of a 0.4-μm film, and thus, there appears to be little or no interaction of the lubricant with amorphous carbon. These transmission spectra are dramatically different from the spectrum of the lubricant on a carbon-overcoated thin-film disk recorded at grazing incidence. The alteration of the grazing incidence reflection spectrum is due to polarization changes of the light when a strong absorber is measured near a reflecting surface.
Photoacoustic Detection of Rapid-Scan Fourier Transform Infrared Spectra from Low-Surface-Area Solid Samples
Authors: Carter R. O. , Peck M. C. Paputa
Published: June 2005

We have demonstrated that the PAS cell volume, and the state of the background material as well as the interferometer mirror velocity and the cell gas composition, must be controlled when one is recording spectra of solid samples. An optically thick, totally absorbing material with a volume matching that of the sample is needed in order to properly normalize spectra of solid samples. With the proper detection bandwidth, mirror speeds of up to 0.181 cm/s can be used with helium as a transfer medium, for the cell specified. The improvement attained at high frequency by using helium can be as much as 10-fold over that obtained with air. The Helmholtz design of the cell produces a resonance at 1.4 kHz with air and 2.65 kHz with helium. These resonances are also affected by the volume and composition of the gas in the sample chamber. Thus, it is essential to select an appropriate background sample for the purpose of normalizing spectra.
Effect of Atomization Surface on the Quantitation of Vanadium by Electrothermal Atomization Atomic Absorption Spectrometry
Authors: Pantano Paul , Sneddon Joseph
Published: June 2005

The effect of four different atomization surfaces (uncoated graphite, pyrolitically coated graphite, continuously in situ coated graphite, and molybdenum coated graphite) on the quantitation of vanadium by electrothermal atomization atomic absorption spectrometry was investigated. For the four different surfaces, tube lifetimes ranged from a high of 410 firings (uncoated graphite) to a low of 230 firings (molybdenum coated graphite), mass changes in the range from 5.6 to 7.2% were found, and the peak shape from the uncoated and pyrolytically graphite surface approached a good degree of symmetry. The single addition of several matrix modifiers to an uncoated graphite surface affected the signal over a range of −106.5% for ammonium molybdate to +12.3% for magnesium nitrate. A combined matrix modifier improved the signal from all four surfaces in the range from 12.8 to 34.0%. Detection limits ranged from 2 μg/L for the pyrolytic surface to 19 μg/L for the molybdenum coated surface. Electron micrographs of the four surfaces at various stages of the tube lifetime showed the deterioration of the surface with increasing use.
Field Applications of Fiber-Optic Sensors. Part I: Temperature Measurements in a Geothermal Well
Authors: Angel S. M. , Garvis D. G. , Sharma S. K. , Seki A.
Published: June 2005

We have initiated a program for developing and field testing fiber-optics-based sensors to monitor in situ physical and chemical parameters in highly corrosive environments, such as geothermal wells, oil wells, and hot-water boiler reactors. Inability to sample hot geothermal wells or to measure the chemical composition of hot brines limits our understanding of in situ conditions in geothermal fields. In this communication, we report preliminary results obtained with a temperature optrode to profile the temperature in a geothermal steam well. To our best knowledge, this is the first time in situ geothermal well measurements have been made with the use of a fiber-optic sensor.
Characterization of Chromium(III) Acetate in Aqueous Solution
Authors: Tackett James E.
Published: June 2005

FT-IR, 2H NMR, FAB mass spectrometry, and ion exchange chromatography were used to characterize structures in chromium acetate solutions prepared under several different conditions. Infrared and 2H NMR peaks for ionic, unidentate, bidentate, and bridging acetate groups were assigned on the basis of chemical information and appearance/disappearance correlations. FAB mass spectrometry was used to confirm the existence of the cyclic chromium trimer in solution. Ion exchange chromatography allowed separation of the complexes based on ionic charge. Replacement of acetate groups by hydroxyl groups causes ring opening and the formation of linear species. Many commercial chromium(III) acetates contain oxalate as well as acetate ligands.
Early Detection of C-130 Aircraft Engine Malfunction by Principal Component Analysis of the Wear Metals in C-130 Engine Oil
Authors: Hancock Darrell O. , Synovec Robert E.
Published: June 2005

Spectrophotometry analysis of engine oil for wear metal to detect engine malfunctions and failing engine components is the basis of the United States Air Force Spectrophotometric Oil Analysis Program (SOAP). This program was abandoned for C-130 transport aircraft because of difficulties in correlating the atomic emission spectroscopy data with engine problems. Principal component analysis (PCA), a factor analysis method, reveals information and structure not previously apparent in the C-130 oil analysis data. These results suggest that the C-130 SOAP program could be made viable with the significant advantages obtained through incorporation of PCA.
Selection of Samples for Calibration in Near-Infrared Spectroscopy. Part I: General Principles Illustrated by Example
Authors: Næs Tormod , Isaksson Tomas
Published: June 2005

General principles for the selection of samples in the calibration of near-infrared (NIR) spectrophotometers are discussed. The discussion ends with suggestions of alternative strategies, which are illustrated by examples.
Study of Alkoxide Silica Gels by Infrared Spectroscopy
Authors: Wood D. L. , Rabinovich E. M.
Published: June 2005

The infrared spectra of silica gels made from alkoxides are different from those made from fumed silica, and from the infrared spectra of other amorphous silicas in which the SiO2 network is relatively complete. One important feature of these spectra is the occurrence of an absorption band at 960 cm−1 due to the vibration of dangling -Si-OH bonds in the alkoxide gels, which is not present in many other silicas. There also are less well-defined absorption bands due to structural defects for the alkoxide gels, but their interpretation is speculative. Dried gels made with more concentrated reactants contain more defects, and heat treatment reduces the concentration of dangling bonds, especially above 900°C. For gels containing fluorine, two absorption bands appear at 932 and 980 cm−1, and these are interpreted as arising from terminal -SiF and -SiF2 groups, respectively.
The Determination of Impurities in Plutonium Metal by Anion Exchange and ICP/AES
Authors: Huff Edmund A. , Bowers Delbert L.
Published: June 2005

The determination of trace-metal impurities in plutonium metal was investigated with the use of anion exchange separation and analysis by inductively coupled plasma/atomic emission spectrometry. Data on recoveries and independent measurements for some 30 elements show precisions and accuracies in the 1–10% range, values that are a significant improvement over those of traditional carrier distillation techniques. Americium can be determined on the same sample aliquot, with figures of merit rivaling those of nuclear counting procedures.
The Effect of a Single Defective Mask Element on the Multiplex Advantage in Hadamard Transform Spectroscopy
Authors: Dyer Stephen A. , Park Jin Bae
Published: June 2005

The effect of a single defective mask element on the output signal-to-noise ratio (SNR) for a stationary-mask Hadamard transform (HT) spectrometer is investigated. The decrease in output-SNR from that of an HT spectrometer having a perfect mask is found to be dependent on the amount of energy impinging on the defective element. A method of compensating for the defective mask element is presented. The method is computationally inexpensive and can be fully automated.
An Analysis for the Composition and Film Thickness of Organic Layered Photoconductors. Part I: Complex Refractive Indices over the Infrared for Hydroxysquarilium and Chlorodiane Blue Charge Generation Dyes
Authors: Pacansky J. , Waltman R. J. , Grygier R.
Published: June 2005

The composition and film thickness of organic layered photoconductors containing the charge generation dyes hydroxysquarilium and chlorodiane blue are analyzed by specular reflectance infrared spectroscopy. The analysis involves recording the infrared spectrum of the photoconductor after the dye layer is coated onto an appropriate substrate. Since the IR spectra are recorded in a specular reflection mode, modeling is required in order to understand the relationship between reflectance and film thickness for the dye layers. Thus a dispersion analysis is used to determine the complex refractive indices over the infrared for the charge generation dyes hydroxysquarilium and chlorodiane blue.
Spectral Study of Promethium and Samarium by Resonance Ionization Mass Spectrometry
Authors: Young J. P. , Shaw R. W. , Smith D. H.
Published: June 2005

A spectral study of promethium and samarium in the wavelength ranges of 530 to 560 and 580 to 615 nm has been made by resonance ionization mass spectrometry. A total of 54 promethium and 35 samarium ionization wavelengths were found. These optical routes are thought to involve a single-color, three-photon process. On the basis of this premise, new qualitative spectral information for both these elements is obtained from these data, and directions for more definitive studies result.
Pyrolysis-GC/FT-IR Analysis for Silane Coupling Treatment of Glass Fibers
Authors: Nishio Etsuo , Ikuta Nobuo , Hirashima Tsuneaki , Koga Joichi
Published: June 2005

Pyrolysis gas chromatography coupled with FT-IR (Py-GC/FT-IR) has been applied to the study of silane treatment of E-glass fiber. The glass fiber treated with a silane coupling agent, γ-anilinopropyltrimethoxy-silane (AnPS), is pyrolyzed at 750°C. The pyrolysates are fractionated by GC and analyzed by FT-IR. The main fraction is assigned to the organofunctional group of the coupling agent. Thus, Py-GC/FT-IR enables us to identify the treated coupling agent qualitatively. A mixture of two different coupling agents, AnPS and γ-methacryloxypropyltrimethoxysilane on glass fiber, is separated and characterized from the spectra of fractions resulting from each coupling agent. Py-GC/FT-IR also provides quantitative information regarding the coupling agents on glass fiber. The total amount of the treated coupling agent is estimated according to the calibration curves, which are proportional to the amount of the coupling agent. Moreover, Py-GC/FT-IR enables us to evaluate the fixing ratio of the coupling agent to the total amount through washing the samples with methanol. The fixing ratio falls significantly above treatment concentration. This tendency is consistent with the results from nondestructive sampling preparation techniques in infrared spectroscopy. The above results indicate the usefulness of Py-GC/FT-IR for the evaluation of silane treatment.
A Model for Time-Resolved Photothermal Spectroscopy of Reactions in Condensed Media
Authors: Schoonover J. R. , Lin S. H.
Published: June 2005

A theory for time-resolved photothermal spectroscopy is proposed for in situ determination of reaction and phase transformation kinetics and mechanisms in condensed media. The theory is developed from the thermal diffusion equation for thin slabs of materials with a finite optical absorption coefficient undergoing a first-order process. The ratio of the photo-response to the total thermal response is evaluated for various reaction kinetics, and a series of time-resolved spectra is constructed.
Chemical and Physical Effects upon Carbonyl Stretching Frequencies: Ketones
Authors: Nyquist R. A. , Chrzan V. , Houck J.
Published: June 2005

The carbonyl stretching frequencies for a series of ketones occur at a lower frequency in dimethyl sulfoxide solution than in carbon tetrachloride solution, and occur at intermediate frequencies depending upon the mole percent ratio (CH3)2SO/CCl4. Ketones of form (CH3)2C=O, φ(C=O)CH3, and (φ)2C=O exhibit carbonyl stretching frequencies which are affected in the same manner by solvent effects. In general, inductive and resonance effects play an important role in determining the unperturbed carbonyl stretching frequencies of ketones.
An Instrumental System for Simultaneous Measurement of Spatially Resolved Electron Number Densities in Plasmas
Authors: Olesik John W. , Den Su-Jane , Bradley Kathryn R.
Published: June 2005

An instrumental system based on a two-dimensional detector to measure electron number densities in plasmas is described. High-resolution H spectra are detected simultaneously at up to 200 spatial locations. Radially resolved electron number densities are determined, following Abel inversion and comparison of H line profiles to theoretical Stark-broadened spectra. The particular interpolation procedure used to calculate H spectra from discrete literature data can affect the calculated electron number density values. Radially and vertically resolved electron number maps for inductively coupled plasmas supported in Fassel-type and low-flow torches are presented. Electron number densities in the center of the 1.0-kW ICPs are less than 2.5 × 1014 cm−3. Short-term precision is better than 1% relative standard deviation except low in the center of the plasma, where the H intensity is low on-axis and larger off-axis.
In Situ, Real-Time FT-IR/CIR/ATR Study of the Biocorrosion of Copper by Gum Arabic, Alginic Acid, Bacterial Culture Supernatant and Pseudomonas atlantica Exopolymer
Authors: Jolley John G. , Geesey Gill G. , Hankins Michael R. , Wright Randy B. , Wichlacz Paul L.
Published: June 2005

Thin films (2.0 nm) of copper on germanium internal reflection elements (IREs) were exposed to 10% gum arabic (aqueous solution), 2% alginic acid (aqueous solution), 1% bacterial culture supernatant (BCS, simulated seawater solution), and 0.5% Pseudomonas atlantica exopolymer (simulated seawater solution) and monitored in situ, real time, with the use of Fourier transform infrared/cylindrical internal reflection/attenuated total reflection spectroscopy as a function of time at ambient conditions. Ancillary graphite furnace atomic absorption spectroscopy was used to monitor the removal process of the copper thin film from the germanium IREs. Results indicate that some of the copper was removed from the Cu/Ge interface by all four polymers and incorporated into the polymer matrix. Thus, biocorrosion of copper was exhibited by the four polymers in the order of alginic acid < gum arabic < BCS > Pseudomonas atlantica exopolymer. The FT-IR/CIR/ATR technique can be successfully used to monitor biocorrosion systems in in situ, real-time settings.
The Effect of Pressure on the Raman and Absorption Spectra of PrCl3, PrBr3, and NdBr3
Authors: Wilmarth W. R. , Begun G. M. , Haire R. G. , Young J. P. , Peterson J. R.
Published: June 2005

Solid-state absorption and Raman phonon spectroscopic investigations of PrCl3, PrBr3, and NdBr3 under high pressure have been carried out at room temperature. These studies showed that the UCl3-type hexagonal form of PrCl3 and PrBr3 converts with the application of pressure to the PuBr3-type orthorhombic crystal structure. The absorption and Raman spectra obtained from PrBr3 and NdBr3 at pressures above ∼260 kbar exhibit differences from spectra obtained at lower pressures, where they exhibit the PuBr3-type orthorhombic structure. These spectral differences suggest that a phase transformation might have taken place to an as-yet-unidentified crystal structure.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XV
Authors: Coleman W. M. , Gordon Bert M.
Published: June 2005

Matrix isolation Fourier transform infrared spectra (MI/FT-IR) of a series of essential oil components have been described. Clear, well-defined differences were detected in the MI/FT-IR spectra of compounds having minor differences in their structure. A library search routine was found to correctly identify components of interest when visual differences were not clearly evident. The presence of discrete conformers in the argon matrix resulted in the presence of split absorptions in the carbonyl band for selected compounds.
Study of the Radiative Properties of Natural and Synthetic Fibers in the 0.25–2.5 µm Region
Authors: Papini Marie
Published: June 2005

Measurements of the reflectance for the solar radiation spectrum of natural and synthetic fibers have been made with an integrating sphere. The obtained spectra are shown to relate to the chemical composition of the materials. The influence that moisture and blending of fibers have on the monochromatic, directional, hemispherical reflection factor is shown.
Chemical Shift Effects in NMR Imaging of Adhesives and Adhesive Joints
Authors: Nieminen Antti O. K. , Koenig Jack L.
Published: June 2005

Chemical shift effects in nuclear magnetic resonance imaging (NMRI) of adhesives are demonstrated and discussed. The effects of more than one proton resonance on slice selection and on the final image are shown. Relative chemical shift effects are introduced to explain, numerically, how sample size, spectral width, and gradient strengths affect the observed image. The potential and limitations of using chemical shift effects in adhesive studies are discussed with illustrative examples. A model adhesive system was studied which was a typical solventless two-component polyurethane adhesive.
Deconvolution of Near-Infrared Spectra
Authors: Nadler T. K. , McDaniel S. T. , Westerhaus M. O. , Shenk J. S.
Published: June 2005

Deconvolution is a mathematical technique for improving the resolution of spectra. Deconvolution can be done in either signal space or frequency space. Both methods were attempted after special adaptations of the algorithms were carried out in order to make them specific for the near-infrared (NIR) spectrum. Signal-space deconvolution works well when a line is subtracted from the spectrum before a modified Jansson's algorithm is applied. Frequency-space deconvolution requires the addition of a polynomial tail to the spectrum, the addition of a constant to the bandpass divisor, and a Gaussian apodization function.
Multifrequency Phase-Modulation Fluorescence Lifetime Determinations On-the-Fly in HPLC
Authors: Cobb W. Tyler , McGown Linda B.
Published: June 2005

The first use of a multifrequency, phase-modulation spectrofluorometer for fluorescence lifetime determinations on-the-fly in HPLC is described. Direct, simultaneous measurements of fluorescence intensity, phase-shift, and demodulation are made at one-second intervals for polycylic aromatic hydrocarbons as they are eluted from the chromatograph. Fluorescence lifetime is calculated from both the phase-shift and the demodulation; the two independent values can be used to indicate the absence or presence of more than one component at any point in the chromatogram. Special considerations regarding data correction and calibration for phase-modulation lifetime determinations under continuous-flow conditions are discussed, along with effects of flow rate and mobile phase composition.
Signal-to-Noise Ratio Enhancement of Spectra using Recursive Integration
Authors: Williams Ron
Published: June 2005

A recursive algorithm independent of any functional peak shape is presented for determining optimal integration limits of spectral data from multiwavelength spectrometers. The resulting areas have significantly higher signal-to-noise ratios than the peak maxima. Signal-to-noise ratios are computed for synthetic data with both shot and white noise limitations. The algorithm is also applied to data from a Fourier transform spectrometer. For these data, integration of 25 adjacent spectral elements improves the signal-to-noise ratio as well as the signal averaging peak maxima from 25 successive spectra.
Spatially Encoded Fourier Transform Spectroscopy in the Ultraviolet to Near-Infrared
Authors: Sweedler Jonathan V. , Denton M. Bonner
Published: June 2005

A spatial (Sagnac triangular common path) interferometer is described and evaluated for obtaining spectra in the 200–950 nm wavelength region. The interferometer has no moving parts, requires no entrance or exit slits, and is easy to align. A linear CCD is employed as the detector, allowing spectra to be simultaneously acquired. The performance of the interferometer is demonstrated for atomic emission and solution absorbance spectra. A method to remove the fixed-pattern response of the detector and optical system is demonstrated which effectively increases the dynamic range of the resulting spectra.
Expression of a Wild-type CFTR Maintains the Integrity of the Biosynthetic/Secretory Pathway in Human Cystic Fibrosis Pancreatic Duct Cells
Authors: Hollande Etienne , Salvador-Cartier Christel , Alvarez Laetitia , Fanjul Marjorie
Published: June 2005

The structural integrity of the Golgi complex is essential to its functions in the maturation, sorting, and transport of plasma membrane proteins. Previously, we demonstrated that in pancreatic duct CFPAC-1 cells, which express δF508 CFTR (cystic fibrosis transmembrane conductance regulator), the intracellular trafficking of carbonic anhydrase IV (CA IV), a membrane protein involved in HCO3− secretion, was impaired. To determine whether these abnormalities were related to changes in the Golgi complex, we examined the ultrastructure and distribution of Golgi compartments with regard to the microtubule cytoskeleton in CFPAC-1 cells transfected or not with the wild-type CFTR. Ultrastructural and immunocytochemical analysis showed that in polarized CFPAC-1 cells, Golgi stacks were disconnected from one another and scattered throughout the cytoplasm. The colocalization of CA IV with markers of Golgi compartments indicated the ability of stacks to transfer this enzyme. This Golgi dispersal was associated with abnormal microtubule distribution and multiplicity of the microtubule-organizing centers (MTOCs). In reverted cells, the normalization of Golgi structure, microtubule distribution, and MTOC number was observed. These observations suggest that the entire biosynthetic/secretory pathway is disrupted in CFPAC-1 cells, which might explain the abnormal intracellular transport of CA IV. Taken together, these results point to the fact that the expression of δF508 CFTR affects the integrity of the secretory pathway.
Immunoexpression of Tyro 3 Family Receptors—Tyro 3, Axl, and Mer—and Their Ligand Gas6 in Postnatal Developing Mouse Testis
Authors: Wang Huizhen , Chen Yongmei , Ge Yehua , Ma Pengpeng , Ma Quanhong , Ma Jing , Wang Haikun , Xue Shepu , Han Daishu
Published: June 2005

Tyro 3 family receptors contain three members—Tyro 3, Axl, and Mer—that are essential regulators of mammalian spermatogenesis. However, their exact expression patterns in testis are unclear. In this study, we examined the localizations of Tyro 3, Axl, Mer, and their ligand Gas6 in postnatal mouse testes by immunohistochemistry. All three members and their ligand were continuously expressed in different testicular cells during postnatal development. Tyro 3 was expressed only in Sertoli cells with a varied distribution during testis development. At day 3 postnatal, Tyro 3 was distributed in overall cytoplasmic membrane and cytoplasm of Sertoli cells. From day 14 to day 35 postnatal, Tyro 3 appeared on Sertoli cell processes toward the adlumenal compartment of seminiferous tubules. A stage-dependent Tyro 3 immunoexpression in Sertoli cells was shown by adulthood testis at day 56 postnatal with higher expression at stages I-VII and lower level at stages IX-XII. Axl showed a similar expression pattern to Tyro 3, except for some immunopositive Leydig cells detected in mature testis. In contrast, immunostaining of Mer was detected mainly in primitive spermatogonia and Leydig cells, whereas a relative weak signal was found in Sertoli cells. Gas6 was strongly expressed in Leydig cells, and a relative weak staining signal was seen in primitive spermatogonia and Sertoli cells. These immunoexpression patterns of Tyro 3 family receptors and ligand in testis provide a basis to further study their functions and mechanisms in regulating mammalian spermatogenesis.
Nuclear Expression of Thymidylate Synthase in Colorectal Cancer Cell Lines and Clinical Samples
Authors: Bissoon-Haqqani Seema , Moyana Terence , Jonker Derek , Maroun Jean A. , Birnboim H. Chaim
Published: June 2005

Thymidylate synthase (TS) [TYMS; OMIM reference number (188, 350)] is normally considered to be a cytoplasmic enzyme. However, a few reports have suggested it may also be present in the nucleus. To explore this in more detail, we used a highly specific polyclonal antibody to TS and a combination of techniques, including immunocytochemistry, confocal microscopy, cell fractionation, and Western blotting. We developed cell line HeLa-55, a HeLa derivative that grossly overexpresses TS. Although the vast majority of TS was in the cytoplasm, some TS also was seen in the nucleus. TS in parental HeLa cells and in normal human fibroblasts was seen exclusively in the cytoplasm. HeLa-55 cells exposed to 5-fluorodeoxyuridine were fractionated and examined by Western blotting. Interestingly, both free TS and the ternary complex of TS were seen in the cytoplasmic fraction but only free TS was detected in the nuclear fraction. Amongst different cell lines examined, HCT-15 and normal fibroblasts showed no nuclear TS, HCC-2998 and SW-620 showed a small amount of nuclear TS, and HT-29, RKO, and HCT-116 showed a strong nuclear TS signal. Nuclear staining was clearly evident in some clinical colorectal specimens, both normal and malignant. This staining was definitively shown to be TS by competition with recombinant TS protein. A putative leucine-rich nuclear export sequence was identified but its function could not be confirmed. We conclude that small amounts of TS protein is present in the nucleus of some cell types but further work is needed to determine the significance of this observation.
Differential Cellular Expression of Galectin Family mRNAs in the Epithelial Cells of the Mouse Digestive Tract
Authors: Nio Junko , Kon Yasuhiro , Iwanaga Toshihiko
Published: June 2005

Galectin is an animal lectin that recognizes β-galactosides of glycoconjugates and is abundant in the gut. This study revealed the cellular expression of galectin subtypes throughout the mouse digestive tract by in situ hybridization. Signals for five subtypes (galectin-2, -3, -4/6, and -7) were detected exclusively in the epithelia. In the glandular stomach, galectin-2 and -4/6 were predominantly expressed from gastric pits to neck of gastric glands, where mucous cells were the main cellular sources. The small intestine exhibited intense, maturation-associated expressions of galectin-2, -3, and -4/6 mRNAs. Galectin-2 was intensely expressed from crypts to the base of villi, whereas transcripts of galectin-3 gathered at villous tips. Signals for galectin-4/6 were most intense at the lower half of villi. Galectin-2 was also expressed in goblet cells of the small intestine but not in those of the large intestine. In the large intestine, galectin-4/6 predominated, and the upper half of crypts simultaneously contained transcripts of galectin-3. Stratified epithelium from the lip to forestomach and anus intensely expressed galectin-7 with weak expressions of galectin-3. Because galectins in the digestive tract may be multi-functional, information on their cell/stage-specific expression contributes to a better understanding of the functions and pathological involvements of galectins.
Histochemical Analyses of Altered Fetal Lung Development Following Single vs Multiple Courses of Antenatal Steroids
Authors: Pua Zarah J. , Stonestreet Barbara S. , Cullen Anne , Shahsafaei Aliakbar , Sadowska Grazyna B. , Sunday Mary E.
Published: June 2005

A single course of antenatal steroids is widely used during preterm labor to promote fetal lung maturation. However, little is known regarding efficacy and safety of multiple courses of antenatal steroids. In animal models and clinical trials, treatment with glucocorticoids can inhibit growth. The present study of single- vs multiple-course steroids in pregnant ewes analyzes the effects of steroids vs placebo on fetal lung histopathology. Single-course groups received dexamethasone (Dex) 6 mg or normal saline every 12 hr for 48 hr at 104-106 days of gestation (term = 150 days). Multiple-course groups received the first course at 76-78 days; this was repeated weekly for 5 weeks. At 108 days, lungs were analyzed using immunohistochemistry for α-smooth muscle actin, a myofibroblast marker and proliferating cell nuclear antigen. Cell injury/death was evaluated using TdT-mediated dUTP digoxigenin nick end labeling (TUNEL) analysis. Although fetal growth was restricted by either single or multiple courses of Dex, alveolar development was accelerated as measured by mean linear intercepts. Alveolar walls were thinner, developing septa were longer, and septal myofibroblasts were increased for both Dex groups compared with controls. Cell proliferation increased following multiple steroid courses, especially in the distal parenchyma, with a corresponding decrease in apoptosis. These observations suggest that Dex promotes alveolarization, whether given in single or multiple courses.
Protein-embedding Technique: A Potential Approach to Standardization of Immunohistochemistry for Formalin-fixed, Paraffin-embedded Tissue Sections
Authors: Shi Shan-Rong , Liu Cheng , Perez Jeanette , Taylor Clive R.
Published: June 2005

A serial study was performed to develop a protein-embedding technique for standardization of immunohistochemistry (IHC) on formalin-fixed, paraffin-embedded (FFPE) tissue sections. A protein carrier matrix must have two phases, a liquid phase to allow uniform mixing of a protein and a solid phase forming a ‘block’ that can be fixed and processed in the same manner as human tissue. This standardized protein block would serve as a source of thin sections for control of IHC and therefore must also withstand the boiling conditions of antigen retrieval (AR). After multiple experiments, a method was developed utilizing polymer microsphere (beads) as a support medium for protein. The method showed particular promise for quantitative IHC.
Genome-Wide Characterization of Tetrahymena thermophila Chromosome Breakage Sites. II. Physical and Genetic MappingSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession nos. AY653004, AY653005, AY653006, AY653007, AY653008, AY653009, AY653010, AY653011, AY653012, AY653013, AY653014, AY653015, AY653016, AY653017, AY653018, AY653019, AY653020, AY653021, AY653022, AY653023, AY653024, AY653025, AY653026, AY653027, AY653028, AY653029.
Authors: Cassidy-Hanley Donna , Bisharyan Yelena , Fridman Vladimir , Gerber Joseph , Lin Cindy , Orias Eduardo , Orias Judith D , Ryder Hilary , Vong Linh , Hamilton Eileen P
Published: June 2005

The chromosomes of the macronuclear (expressed) genome of Tetrahymena thermophila are generated by developmental fragmentation of the five micronuclear (germline) chromosomes. This fragmentation is site specific, directed by a conserved chromosome breakage sequence (Cbs element). An accompanying article in this issue reports the development of a successful scheme for the genome-wide cloning and identification of functional chromosome breakage sites. This article reports the physical and genetic characterization of 30 functional chromosome breakage junctions. Unique sequence tags and physical sizes were obtained for the pair of macronuclear chromosomes generated by fragmentation at each Cbs. Cbs-associated polymorphisms were used to genetically map 11 junctions to micronuclear linkage groups and macronuclear coassortment groups. Two pairs of junctions showed statistically significant similarity of the sequences flanking the Cbs, suggestive of relatively recent duplications of entire Cbs junctions during Tetrahymena genome evolution. Two macronuclear chromosomes that lose at least one end in an age-related manner were also identified. The whole-genome shotgun sequencing of the Tetrahymena macronucleus has recently been completed at The Institute for Genome Research (TIGR). By providing unique sequence from natural ends of macronuclear chromosomes, Cbs junctions will provide useful sequence tags for relating macro- and micronuclear genetic, physical, and whole-genome sequence maps.
A Comparison of Three Estimators of the Population-Scaled Recombination Rate: Accuracy and Robustness
Authors: Smith Nick G C , Fearnhead Paul
Published: June 2005

We have performed simulations to assess the performance of three population genetics approximate-likelihood methods in estimating the population-scaled recombination rate from sequence data. We measured performance in two ways: accuracy when the sequence data were simulated according to the (simplistic) standard model underlying the methods and robustness to violations of many different aspects of the standard model. Although we found some differences between the methods, performance tended to be similar for all three methods. Despite the fact that the methods are not robust to violations of the underlying model, our simulations indicate that patterns of relative recombination rates should be inferred reasonably well even if the standard model does not hold. In addition, we assess various techniques for improving the performance of approximate-likelihood methods. In particular we find that the composite-likelihood method of Hudson (2001) can be improved by including log-likelihood contributions only for pairs of sites that are separated by some prespecified distance.
Adult Myogenesis in Drosophila melanogaster Can Proceed Independently of Myocyte Enhancer Factor-2
Authors: Baker Phillip W , Tanaka Kathleen K Kelly , Klitgord Niels , Cripps Richard M
Published: June 2005

Myocyte enhancer factor-2 (MEF2) is a transcription factor that is necessary for embryonic muscle development in Drosophila and vertebrates; however, whether this factor is required during later muscle development remains largely unknown. Using heteroallelic combinations of different Mef2 mutant alleles, we isolated and characterized a temperature-sensitive combination. Through temperature-shift experiments, we obtained adult animals that were lacking proper MEF2 function. Many of these individuals died as mature pupae, and those that eclosed showed poor locomotion and an inability to fly. Histological analysis of these animals revealed a requirement for MEF2 in skeletal muscle patterning, although these animals had strikingly normal amounts of muscle tissue. Using quantitative polymerase chain reaction, we determined that expression of the MEF2-regulated actin gene Act57B was severely reduced in these animals. By contrast myofibrillar actin genes unique to the adult stage were only mildly affected. Since MEF2 mutant adults were still capable of forming muscle tissue, we conclude that MEF2 is required for the expression of only a subset of muscle structural genes in the adult. These results indicate that additional muscle-specific factors function to control the myogenesis of complex and diverse muscle in the adult.
NinR- and Red-Mediated Phage-Prophage Marker Rescue Recombination in Escherichia coli
Authors: Hayes Sidney , Asai Kengo , Chu Audrey M , Hayes Connie
Published: June 2005

We examined the requirement of λ recombination functions for marker rescue of cryptic prophage genes within the Escherichia coli chromosome. We infected lysogenic host cells with λimm434 phages and selected for recombinant immλ phages that had exchanged the imm434 region of the infecting phage for the heterologous 2.6-kb immλ region from the prophage. Phage-encoded activity, provided by either Red or NinR functions, was required for the substitution. Red− phages with ΔNinR, internal NinR deletions of rap-ninH, or orf-ninC were 117-, 12-, and 5-fold reduced for immλ rescue in a Rec+ host, suggesting the participation of several NinR activities. RecA was essential for NinR-dependent immλ rescue, but had slight influence on Red-dependent rescue. The host recombination activities RecBCD, RecJ, and RecQ participated in NinR-dependent recombination while they served to inhibit Red-mediated immλ rescue. The opposite effects of several host functions toward NinR- and Red-dependent immλ rescue explains why the independent pathways were not additive in a Rec+ host and why the NinR-dependent pathway appeared dominant. We measured the influence of the host recombination functions and DnaB on the appearance of oriλ-dependent replication initiation and whether oriλ replication initiation was required for immλ marker rescue.
Portrait of a Species
Authors: Pröschold Thomas , Harris Elizabeth H , Coleman Annette W
Published: June 2005

Chlamydomonas reinhardtii, the first alga subject to a genome project, has been the object of numerous morphological, physiological, and genetic studies. The organism has two genetically determined mating types (plus and minus) and all stages of the simple life cycle can be evoked in culture. In the nearly 60 years since the first standard laboratory strains were isolated, numerous crosses and exchanges among laboratories have led to some confusion concerning strain genealogy. Here we use analyses of the nuclear internal transcribed spacer regions and other genetic traits to resolve these issues, correctly identify strains currently available, and analyze phylogenetic relationships with all other available similar chlamydomonad types. The presence of a 10-bp indel in ITS2 in some but not all copies of the nuclear ribosomal cistrons of an individual organism, and the changing ratios of these in crosses, provide a tool to investigate mechanisms of concerted evolution. The standard C. reinhardtii strains, plus C. smithii  +, plus the new eastern North American C. reinhardtii isolates, comprise one morphological species, one biological species of high sexual intercompatibility, and essentially identical ITS sequences (except the tip of helix I of ITS2). However, variant RFLP patterns characterize strains from each geographic site.