bluuebunny/crossref_metadata_2025 huggingface dataset:
Luminescence Instrument for the Acquisition of Low-Temperature Fluorescence and Phosphorescence Spectra
Authors: Pace Charles F. , Thornberg Steven M. , Maple Jon R.
Published: July 2005

An inexpensive, simple (but highly automated) instrument for acquiring high-resolution fluorescence and phosphorescence spectra of polycyclic aromatic hydrocarbons (PAHs) is described. Fluorescence and phosphorescence signals are processed by gated integration and photon counting, respectively. The instrument can be used to acquire excitation as well as emission spectra in both the frequency and time domain. In addition, a method for measuring single and double exponential phosphorescence decay times is presented. Decay times ranging from 0.3 ms to 300 ms were measured for several naphthalene derivatives, with a precision of ∼10%. The primary advantages of this instrument are high sensitivity, high selectivity, wide linear dynamic ranges, and a versatile range of applications.
The Improvement of Mossbauer Spectra by FIRO Deconvolution
Authors: Rex A. F. , Olson M. A. , Silva N. J.
Published: July 2005

A deconvolution method similar to that used by Shimokoshi, Kanzaki, and Jones [Applied Spectroscopy 39, 1014 (1985)] has been used to study 57Fe Mossbauer spectra containing various mixtures of iron compounds. In all cases the spectra studied contained one or more sets of overlapping spectral lines. The resolution of these overlapping lines can often be improved by deconvolution to the point at which the integrated intensities of the deconvoluted peaks provide reliable information about sample concentrations. A comparison of the results which can be obtained for different deconvolution parameters and different degrees of overlapping is presented.
Comparison of Infrared Spectroscopic Methods for the Quantitative Analysis of Epoxy Resins Used in Carbon-Epoxy Composite Materials
Authors: Cole K. C. , Pilon A. , Noël D. , Hechler J.-J. , Chouliotis A. , Overbury K. C.
Published: July 2005

Three different methods of obtaining the infrared spectrum of carbon-epoxy prepreg for quality control purposes are critically evaluated with respect to their suitability for quantitative analysis. They are: transmission using a cast film of resin, attenuated total reflection (ATR) using prepreg, and diffuse reflection (DR) using prepreg. The cast film method is subject to significant error resulting from nonuniform film thickness; careful sample preparation is necessary in order to obtain acceptable results. The ATR method is faster and easier to use than the transmission method and gives more reproducible results; the use of a 45° germanium prism is recommended. The DR method is not suitable for quantitative work because of complications arising from front-surface reflection effects; it can be very useful, however, as a qualitative method.
Weathering of a Metal Artifact in a Saharan Environment: Evidence for a Novel Form of Desert Varnish
Authors: Eastes John W. , Hearn Paul P. , McCauley John F.
Published: July 2005

A dark-brown coating on the exterior of a World War II metal fuel can recovered in southwestern Egypt may be a variation of the desert varnish that develops on rock surfaces in arid regions. This suggestion is supported by results of infrared spectroscopic work, x-ray diffraction, scanning electron microscopic studies, and x-ray fluorescence. Exterior portions of the can resemble heavily varnished rock, differing completely in appearance and texture from rusty areas which had developed on portions of the interior surface. The coating consists principally of microscopic mineral deposits, some of which appear to be largely Fe-oxides and Fe-oxy-hydroxides. However many deposits are assemblages of Fe-oxides, clay minerals, and other elements typically occurring in forms of desert varnish often observed on the undersides of desert pavement stones in contact with the soil. Associated with the mineral matter is an organic component apparently deriving from residues of an original paint layer which had been removed by wind/sand scouring.
Determination of Polycyclic Aromatic Hydrocarbons in Cooked Beef by Low-Temperature Molecular Luminescence Spectrometry Using a Moving Sample Cooling Belt
Authors: Jones Bradley T. , Glick Mark R. , Mignardi Michael A. , Winefordner James D.
Published: July 2005

Four polycyclic aromatic hydrocarbons are identified in broiled hamburger at the part per billion level by low-temperature molecular luminescence spectrometry (LT-MLS). Hamburger extracts in a Shpol'skii solvent are injected onto a moving sample cooling device maintained at 15 K in a vacuum. Results obtained by the present system are compared with those obtained by constant energy synchronous luminescence spectrometry (CESLS) at 77 K and by high-performance liquid chromatography (HPLC) with multiwavelength detection.
Analysis of Intact Tablets by Near-Infrared Reflectance Spectrometry
Authors: Lodder Robert A. , Hieftje Gary M.
Published: July 2005

A typical pharmaceutical tablet is too small for analysis in an ordinary NIRA instrument. An intact tablet will not begin to fill a solid-sample holder designed for use with a powdered sample. Grinding the sample is likewise unproductive, as a single tablet also does not provide enough powder for the sample cup. Potential NIRA applications such as the detection of product tampering and even routine quality control are unnecessarily complicated by this grinding requirement. A method of analyzing single, intact tablets using a double-reflecting aluminum sample holder is described in this report. The integrity of the sample is preserved during the analysis, allowing the tablet to be sold or consumed after the procedure.
Comparison between a TIAP Crystal and a PX1 Multilayer Pseudocrystal in Light Element X-Ray Fluorescence Emission Using Different Excitation Sources
Authors: Grimaldi R. , Mariani E. , Paris V. , Farnè G. , Randi G. , Leoni M.
Published: July 2005

A PX1 multilayer pseudocrystal is compared with a TlAP crystal for the analysis of light elements by means of two different excitation sources, i.e., a chromium and a scandium target tube. Peak and background intensities for Cl, S, P, Si, Al, Mg, Na, F, and O are compared with the use of both a fine and a coarse collimator. The most suitable working conditions for the analysis are pointed out.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part IX
Authors: Coleman W. M. , Gordon Bert M.
Published: July 2005

A series of β-diketones and alkenes have been examined by matrix isolation Fourier transform infrared spectroscopy. The matrix experiment readily detects the presence of extensive keto-enol tautomerization in selected β-diketones. Certain absorption bands in the IR could be used to estimate the extent of the tautomerization. The data gathered on the alkenes found their absorption bands to occur in the same regions (±5 cm−1) as those found for VP and SS phases. Minimal nearest-neighbor (aggregation) interactions were found. These results are in contrast to those found for aldehydes, ketones, and acids of similar chain lengths.
An FT-IR Method for Performing Dynamic Kinetic Experiments
Authors: Snyder Randy W. , Sheen C. Wade
Published: July 2005

A method is shown for the determination of kinetic parameters from dynamic FT-IR experiments. The effect heating rate has on the reproducibility of the calculated activation energy is discussed. The curing of PMDA/ODA polyimide at several heating rates is given as an example.
Room-Temperature Luminescence Properties of p-Aminobenzoic Acid and 4-Phenylphenol Adsorbed on α-Cyclodextrin/NaCl Mixtures
Authors: Bello J. M. , Hurtubise R. J.
Published: July 2005

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on α-cyclodextrin/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol on α-cyclodextrin/NaCl mixtures. In addition, the percentages of radiative and nonradiative transitions were calculated for the two compounds. The various luminescence parameters obtained in this work provided important insights into the analyte/α-cyclodextrin substrate interactions responsible for the observed solid-surface room-temperature fluorescence (RTF) and phosphorescence (RTP). Furthermore, the RTF and RTP intensities of PABA and 4-phenylphenol were obtained from several α-cyclodextrin/NaCl mixtures. These data showed the importance of the initial wet chemistry in the sample preparation procedure.
Radiative and Electrical Properties of a Center-Post Cathode Magnetron Glow Discharge Device
Authors: Tanguay Suzanne , Sacks Richard
Published: July 2005

Current-voltage characteristics and spatially resolved atomic emission data are used to describe the basic operation of a magnetron glow discharge plasma device. The low-pressure glow discharge lamp uses a center-post cathode and a concentric ring-shaped anode. A coaxial magnetic field of a few hundred Gauss is used to achieve magnetron operation where plasma electrons are trapped in closed paths which are concentric with the electrode structure. This results in dramatic changes in the radiative and electrical properties of the device. With constant current, lamp operating voltage may be reduced by more than a factor of two when the magnetic field is present. The effects of filler gas pressure and magnetic field strength on the current-voltage characteristics are presented. The presence of the magnetic field results in a radial contraction of the plasma. This contraction increases with increasing field strength and with decreasing pressure. Ion lines from the Ar filler gas are more affected by the field than are neutral-atom lines from the cathode material.
Self-Absorption in Copper Hollow Cathode Discharges: Effects on Spectral Line Shape and Absorption Sensitivity
Authors: Phillips Hugh A. , Lancaster Herbert L. , Denton M. Bonner , Rózsa Karoly , Apai Pal
Published: July 2005

The intensity of the hyperfine doublet of the Cu(I) 324.8-nm transition was observed as a function of current, fill gas, and fill gas pressure for a new design of hollow cathode lamp incorporating a positive column and an enlarged volume cathode cavity. The intensity ratio of the two components, which reflects the degree of self-absorption, and the flame absorption sensitivity were compared with those of a conventional hollow cathode lamp. Higher intensity, better component ratio, and increased absorption sensitivity were found in the new lamp.
Atomization of Organic Compounds in the Inductively Coupled Plasma
Authors: Hauser P. C. , Blades M. W.
Published: July 2005

The problem of incomplete atomization when nonmetals are being determined in aspirated organic solutions was studied. Abel inverted spatial profiles of C2, CN, C(I) and S(I) emission were acquired at several heights. It was found that molecular emission caused by the analyte is restricted to the lower aerosol channel. Nonmetal atomic emission is found in the toroidal region and higher up in the aerosol channel. Compounds that contained nonmetals comprised of either oxygen, nitrogen, or sulfur, which were dissolved in xylene, exhibited nonmetal emission intensities independent of the structure of the compound.
Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part X
Authors: Coleman W. M. , Gordon Bert M.
Published: July 2005

The characteristics of the OH stretching absorptions in a series of catechols, resorcinols, hydroquinones, and diols have been documented with the use of matrix isolation Fourier transform infrared spectroscopy. Steric and electronic effects were described and found to agree with published results on the vapor-phase studies on the same compounds. The positions of the OH absorptions were shown to fall within a window set on the high energy side by the vapor-phase results and on the lower energy side by solid-state/solution results. The very low full width at half-height values unique to the matrix experiment allowed for the observance of absorption bands not yet seen before in the vapor-phase or solid-state studies. These new bands confirm the presence of intramolecular interactions not previously documented. The data as a whole do indicate that extensive intermolecular interactions do occur at very low loadings on the cryogenic disk (10 ng) for compounds containing polar substituents.
Raman Microspectroscopic Study of the Cation Distribution in Amphiboles
Authors: Wang A. , Dhamelincourt P. , Turrell G.
Published: July 2005

The first attempt to determine the cation distributions in amphiboles by Raman microspectroscopy is described. The Raman spectra of five amphibole samples were obtained. It was observed that the Raman bands of the OH stretching modes were narrower than the corresponding infrared bands previously reported. However, even with the use of the most sophisticated Raman instruments, it was not possible to distinguish the bands due to the different cation arrangements of one particular configuration. Nevertheless, the experimental results and the theoretical analysis developed here allowed approximate calculations of the site occupancies to be made for four samples. These results yield a better understanding of the problems involved in the determination of the cation distributions in amphiboles with the use of vibrational spectroscopic methods.
CARS Spectroscopy of Ammonia in the Laboratory and a Commercial Scale Ammonia Oxidation Plant
Authors: England William A. , Ali Ansar
Published: July 2005

CARS spectra of NH3 have been obtained from a commercial catalytic ammonia oxidation plant operating at ∼10 atmospheres (absolute) and 250°C. A purpose-designed ruggedized CARS spectrometer—incorporating a novel dye laser, remote control, and fiber optic signal transfer—is described. A new and simple technique for CARS concentration analysis using polarized beams gave a precision of 5.9% for NH3 from single-shot spectra under laboratory conditions. Unfortunately, severe beam steering problems were encountered in the full-scale plant; this prevented a quantitative analysis of the spectra obtained. The origins of this problem together with suggestions for overcoming or reducing its effect are given.
A Newly Designed Cryostat for Absorption Spectroscopic Studies of Liquids, Solids, and the Interphases
Authors: Cornut J. C. , Huong P. V. , Graja A. , Daleau G.
Published: July 2005

A double jacket cryostat based on thermal convection between a gaseous cold stream filled in a freezing chamber and the sample cell is described. This device is designed for absorption spectroscopy in the infrared and in the UV-visible regions for gases, liquids, liquefied gases, and solids, as well as for the transitions between these phases or between phases in the solid state, over the range 85 to 340 K, at variable thicknesses and under a pressure of up to 10 bars.
Fourier Transform Fluorescence Spectrometry
Authors: Hlivko B. , Hong H. , Williams R. R.
Published: July 2005

A variety of fluorescence spectra have been measured interferometrically, demonstrating the feasibility of Fourier Transform Fluorescence Spectrometry (FT-FS). Emission spectra have been measured with the use of a monochromatic source and an interferometer as the emission selector. Excitation spectra have been measured with the use of a multi-line laser. Fluorescence polarization spectra have also been recorded with the use of laser excitation. The analytical characteristics of working curves are discussed.
Laser-Induced Photochemical Reactions of Methanol, Ethanol, 1-Propanol, and 2-Propanol
Authors: Johnson R. A. , Stanley A. E.
Published: July 2005

This study focuses on the carbon dioxide laser-induced excitation and resultant dissociation of several members of a group of carbon-oxygen (C-O)-containing molecules, the alcohols methanol, ethanol, 1-propanol, and 2-propanol. The tunable continuous-wave infrared (cw) laser provides the energy of activation necessary for dissociation to occur after absorption into the C-O stretching fundamentals of the alcohols. Chemical reactions were monitored with the use of Fourier transform infrared spectroscopy, also used for identification of end products. After irradiation, ethanol and 1-propanol each yielded acetaldehyde. The products of the dissocation of methanol were carbon monoxide, formaldehyde, and hydrogen. The formaldehyde then reacted with excess methanol to produce methoxymethanol. Fourier transform interferograms were collected at specific time intervals, thus monitoring any consecutive reactions that occurred after the irradiation. For methanol, laser parameters such as output line frequency and power as well as irradiation time were varied. The effect of initial reactant pressure on the laser-induced dissociation of methanol was evaluated. Only methanol underwent a consecutive reaction. Hydrocarbon fragments were also observed from ethanol, 1-propanol, and 2-propanol. Methane, ethene, and ethyne were produced from ethanol. Propene, ethene, and methane were produced from 1-propanol, and methane and propene from 2-propanol. The products observed in some instances were different from those reported in the literature for pyrolytic and pulsed laser studies. The results from these investigations are compared with results from other similar compounds and similar techniques.
An Investigation of the Chemical Variability of Woody Peat by FT-IR Spectroscopy
Authors: Durig D. T. , Esterle J. S. , Dickson T. J. , Durig J. R.
Published: July 2005

Woody peats from Indonesia and Malaysia were examined by FT-IR spectroscopy to observe the variation in degree of humification between peat types and among botanical components and matrix material within a peat type. Results of the FT-IR analysis showed significant changes occurring in the 1600 and 1000 cm−1 regions which are interpreted to represent lignin and lignocellulose, respectively. These components were considered to describe variations in degree of humification. Between peat types the intensity of the lignocellulose region decreased accordingly between fibric, hemic, and sapric samples. Within a sample, variations in the relative amount of lignocellulose in the three different size fractions of a sample were observed that could generally, but not always, be related to peat type. In all peat types the coarse material still contained some lignocellulosic component, whereas the finer fractions contained variably less to no lignocellulose. The lignin-dominated composition of the finer matrix material suggests that these peats are derived mainly from trees and woody vines with little input from herbaceous, less decay-resistant (cellulose-dominant) plant material.
Design and Interfacing of an Automated Langmuir-Type Film Balance to an FT-IR Spectrometer
Authors: Dluhy Richard A. , Mitchell Melody L. , Pettenski Thomas , Beers Jeffery
Published: July 2005

We report the design of a surface analysis accessory that allows for the use of external reflection FT-IR spectroscopy to investigate the structure of insoluble monolayer films in situ at the air/water interface. The Langmuir film balance constructed for this purpose is optimized to contain the monolayer film at the focal point of the infrared beam, as well as to generate high surface pressures within the film. The optical interfacing of the film balance to an FT-IR spectrometer is also described. Results are presented for a representative surface pressure/molecular area isotherm and infrared spectrum for a phospholipid monolayer film.
A Critical Evaluation of Internal Reflection Spectroscopic Methods for Determining Macromolecular Orientation in Polymer Surfaces
Authors: Mirabella Francis M.
Published: July 2005

A critical evaluation was made of the available internal reflection spectroscopic (IRS) methods for the determination of macromolecular orientation in surfaces. A method involving the measurement of band ratios within a single spectrum, which were used to calculate the molecular orientation along the three principle orthogonal axes (MD, TD, and ND), was found to be in good agreement with independent orientation determinations on the same set of oriented polypropylene sheets by x-ray diffraction and polarized refractometry methods. Methods in which dichroic ratios are determined from two separate spectra were shown to lead to unsatisfactory results due to differing sample contact to the internal reflection element (IRE) for each spectrum. This was demonstrated for a method using a rotatable IRE and sample holder which permitted the measurement of spectra along orthogonal axes in the sample without demounting and remounting of the sample. It was found that this method yielded irreproducible results which were not in agreement with the aforementioned independent methods. The reason for the irreproducible results was clearly due to differing sample contact along the two paths through the rotatable IRE—a contact problem that was exacerbated for more highly oriented samples. The conclusion was drawn that only IRS methods involving band ratios within a single spectrum can yield quantitative and reproducible orientation functions, since the sample contact problem does not exist for these methods.
In Situ Fourier Transform Infrared Diffuse Reflectance and Photoacoustic Spectroscopy Characterization of Sulfur-Oxygen Species Resulting from the Reaction of SO2 with CaCO3
Authors: Thompson Meg Martin , Palmer Richard Alan
Published: July 2005

Fourier transform photoacoustic and diffuse reflectance spectroscopies (FT-IR-PAS and -DRS) have been used in situ to monitor the reaction of SO2 (1.5% in N2) with particulate CaCO3 at temperatures up to 400°C (PAS) and 690°C (DRS). The PA spectra indicate that at 360°C SO2 is physisorbed on the CaCO3 surface. This species is readily desorbed by N2 purging. Under continuous SO2/N2 exposure at 400°C and above, the physisorbed species is shown by the DR data to be converted first to oxygen-bound and then to nonspecifically bound pyramidal SO3−. Reaction of the SO3= with SO2 to form SO4− begins at 400°C and is essentially complete at 690°C. The DR data further indicate that for the SO4−: (1) at temperatures between 400 and 640°C a monodentate C3 v species forms; (2) above 640°C the SO4− ion has nearly Td symmetry; and (3) upon subsequent cooling, the SO4− exhibits the characteristics of a chelating C2 v species.
Application of Multidimensional Analyses to the Extraction of Discriminant Spectral Patterns from NIR Spectra
Authors: Devaux M. F. , Bertrand D. , Robert P. , Qannari M.
Published: July 2005

A method for extracting NIR discriminant spectral patterns without any reference to chemical values is suggested. First, groups of samples have to be defined a priori. Second, this method involves two procedures: the application of Principal Component Analysis (PCA) on spectral data and Factorial Discriminant Analysis (FDA) on the PC scores. Discriminant spectral patterns are assessed as linear combinations of PCA eigenvectors with weights determined by FDA. This method was applied on an illustrative collection of wheat semolina conditioned at 3 levels of water concentration. Three groups were made on the basis of the 3 water levels. Two discriminant spectral patterns representative of water concentration were extracted. They showed the commonly known bands of water at 1940 and 1450 nm. The band at 1450 nm was resolved into two bands at 1410 and 1460 nm, which could be assigned to free and bound OH, respectively. The discriminant spectral patterns therefore modeled the relative proportion of free and bound water. Suitability of the method for other applications is discussed.
Detection of Ethanol in Wines Using Optical-Fiber Measurements and Near-Infrared Analysis
Authors: Buchanan B. R. , Honigs D. E. , Lee Cynthia J. , Roth William
Published: July 2005

Optical-fiber measurements coupled with near-infrared analysis is used to predict the ethanol content of wine samples to within ±0.33 volume percent. Because telecommunications-grade optical fibers are used, the wavelength range is limited and the signal-to-noise ratio is an order of magnitude less than that for conventional near-infrared measurements. These features prompted the use of partial least-squares (PLS) as the calibration algorithm. PLS provides robust calibrations that are based upon the entire spectrum. The problem of extreme samples not being represented in the calibration model is discussed and illustrated. Also, the robustness of the PLS calibration is demonstrated. Spectral reconstruction is used to help assign the bands in the wavelength range used.
Time-Resolved Constant-Energy Synchronous Phosphorimetry
Authors: Laserna Javier J. , Mignardi Michael A. , Von Wandruska Ray , Winefordner James D.
Published: July 2005

Constant-energy synchronous scanning has been combined with time resolution in order to increase the spectral selectivity in low-temperature phosphorimetry. The technique is called Time-Resolved Constant-Energy Synchronous Phosphorimetry (TRCESP). The personal computer-controlled flashlamp phosphorimeter consisted of a conventional spectrophosphorimeter with computer control of the scanning of the excitation and emission spectrometers. Temporal features such as the repetition rate, source pulse width, delay time between termination of the source pulse and the gate opening, and detector gate width were under various forms of electronic control. A discussion of the spectral resolution resulting from synchronous scanning and temporal resolution from pulsing the source and gating the detector is given. Several mixtures of phosphors are evaluated with respect to the effect of spatial resolution, temporal resolution, and combination of the two resolution approaches upon both sensitivity and selectivity measurements.
In Situ FT-IR Analysis of a Composite Curing Reaction Using a Mid-Infrared Transmitting Optical Fiber
Authors: Compton David A. C. , Hill Stephen L. , Wright Norman A. , Druy Mark A. , Piche Joseph , Stevenson William A. , Vidrine D. Warren
Published: July 2005

The use of a mid-infrared transmitting fiber to carry the infrared beam of an FT-IR spectrometer outside of the optical bench is reported. In addition it is demonstrated that it is possible to analyze samples using the fiber as an internal reflection element. The fiber is covered with a protective coating which can be removed for a short region, to allow contact with the sample over a controlled length. Two examples of the use of an optical fiber for remote sampling are discussed. The first shows that a spectrum of a liquid sample (2-butanone) can be easily measured, and the second shows how a fiber can be used to monitor the progress of curing reactions in thermoset composite materials. The spectrum of a resin was recorded before the cure by embedding the optical fiber in the graphite fiber/polyimide matrix resin prepreg, and then the progress of the cure was monitored during the curing process. This type of remote sampling shows tremendous potential for opening totally new areas of usage for FT-IR spectrometry, including the studies of hazardous materials, enclosed reactions, and processes that do not allow samples to be taken inside the spectrometer.
Comparison among Several Numerical Integration Methods for Kramers-Kronig Transformation
Authors: Ohta Koji , Ishida Hatsuo
Published: July 2005

Several numerical integration methods are compared in order to search out the most effective method for the Kramers-Kronig transformation, using the analytical formula of the Kramers-Kronig transformation of a Lorentzian function as a reference. The methods to be compared involve the use of (1) Maclaurin's formula, (2) trapezium formula, (3) Simpson's formula, and (4) successive double Fourier transform methods. It is found that Maclaurin's formula, in which no special approximation is necessary for the pole part of the integration, gives the most accurate results, and also that its computation time is short. Successive Fourier transform is less accurate than the other methods, but it takes the least time when used without zero-filling. These results have important relevance for programs used to obtain optical constant spectra and to analyze spectral data.
Spectroscopic and Fluorometric Characterization of Oxacyanine Dyes in Water and Nitrobenzene
Authors: Wiegand Deborah H. , Vanýsek Petr
Published: July 2005

The spectroscopic and fluorometric properties of nine oxacyanine dyes (3,3′-dimethyloxacarbocyanine through 3,3′-diheptyloxacarbocyanine, 3,3′-diethyl-, and 3,3′-dipropyloxadicarbocyanine iodides) were determined in two solvents, water and nitrobenzene. In nitrobenzene the absorbance and fluorometric spectra of the dyes showed a red shift of 15 to 20 nm when compared with the spectra in water. In addition, the fluorescence emission intensity of the dyes is lower in nitrobenzene than in water, by one to two orders of magnitude. Thus it is possible to measure fluorescence in water in water/nitrobenzene systems without interference from the nitrobenzene part. The molar absorptivities of the dyes were calculated and used to determine the solubility of the dyes in water and the partition coefficients of the dyes between nitrobenzene and water. These dyes were characterized in order to provide a better understanding of the properties of the dyes in a water/nitrobenzene interface system which will be used in electrochemical studies of the dyes.
Characterization of Solution-Cast Extracts from Cardiothane-51 ® by FT-IR and ESCA
Authors: Grobe George L. , Nagel Anthony S. , Gardella Joseph A. , Chin Roland L. , Salvati Lawrence
Published: July 2005

Extracts from Cardiothane-51 ® have been cast from solvents of varying polarity. Cardiothane-51® can be described as block polyether-polyurethane copolymer with a 10% by weight addition of polydimethylsiloxane (DMS) that is partially copolymerized and partially blended to form a copolv mer/polv blend. FT-IR has been utilized to probe bulk and near-surface bonding and composition in the solution-cast extract films. Results show that Cardiothane-51 ® is similar in bulk composition, as measured by FT-IR, to Avcothane-51®. However, these two polymers are quite different in composition over a depth of microns. Both Cardiothane-51 ® and Avcothane-51 ® have surfaces, as measured by ESCA, which are dominated by their DMS component with a significant amount of the polyether present. Results suggest that the DMS in Cardiothane-51 ® is a blended phase, because of its ease of extraction.
Interference and ion effects in the electro‐optical response of PDNLC films
Authors: Barannik A. , Shabanov V. , Zyryanov V. , Lapanik V. , Bezborodov V.
Published: July 2005

Abstract— We have considered the interference in polymer‐dispersed nematic liquid‐crystal (PDNLC) films caused by the superposition of light beams that pass through and between the LC droplets. The relative phase retardation of the beams depends on the applied voltage, and, as a consequence, interference oscillations can occur at transmittance‐voltage curves. Typical forms of the curves for composite films with various structures are presented. Interference oscillations were revealed not only in the static electro‐optical characteristics but in the dynamic ones also. For PDLC films based on commercially available components produced without thorough purification, the combination of interference and ionic effects is observed in the dynamics of the optical response. The relaxation of transmittance due to the depolarization ionic field is presented, depending on droplet size, temperature, pulse duration, and the concentration of the ionic admixture.
Diamond‐like‐carbon LC‐alignment layers for application in LCOS microdisplays
Authors: Bol Ageeth , Dvorak Joseph , Arena Dario
Published: July 2005

Abstract— To improve the lifetime and yield of LCOS microdisplays, non‐contact LC alignment techniques using inorganic materials are under investigation. This report focuses on oblique ion‐beam treatment of diamond‐like carbon (DLC) layers, and in particular on the influence of the ion dose on the LC alignment on DLC, keeping the ion‐beam angle (40°) and ion‐beam energy (170 eV) the same. LC alignment on ion‐milled DLC layers is uniform if the ion dose is between 3.8 × 10−4 C/cm2 and 5.5 × 10−3 C/cm2. Above and below this ion dose range, non‐uniform alignment is observed. NEXAFS experiments show that this is caused by lack of molecular anisotropy on the surface of the ion‐milled DLC layers. By varying the ion dose between 3.8 × 10−4 C/cm2 and 5.5 × 10−3 C/cm2, LC molecules have an average pre‐tilt between 3° and 5°, which is within the desired range for application in LCOS microdisplays. The lifetime of the LCOS microdisplays with ion‐milled DLC for projection‐TV application is, however, shorter than the lifetime of microdisplays with PI layers. Ion milling probably creates a reactive surface that is unstable under the high light fluxes used in projection TVs. A solution for this problem could be chemical passivation of the ion‐milled alignment layers. Initial experiments with passivation of ion‐milled PI resulted in an increase in lifetime, but the lifetime after passivation was still lower than the lifetime of rubbed PI layers (factor 0.7). Nevertheless, ion‐milling of DLC or PI can be a good alternative LC alignment technique in other LCD applications. LC‐alignment layers based on inorganic layers such as obliquely deposited SiO2 films would be a better option for application in LCOS microdisplays due to their higher light stability.
Polarized light diffraction on anisotropic substrates with rectangular and sine microrelief
Authors: Belyaev V. V. , Tsoy V. I. , Kushnir E. M. , Klyckov A. V. , Kalashnikov A. Y.
Published: July 2005

Abstract— Light diffraction on optically anisotropic substrates with surface microrelief has been calculated by using the OAGSM method. Varying the microrelief depth and material birefringence allows us to realize different polarization states of the light beam transmitted or reflected by the substrate. The approach can be used to optimize the LCD backlight and control light‐beam propagation for different puposes.
Properties of thin films of organosilicone compounds for LC alignment
Authors: Mazaeva Vera , Belyaev Victor , Sobolevskii Mikhail
Published: July 2005

Abstract— Two different methods of fabricating ultrathin films made of organosilicon compounds (OSC) with various chemical structures on both the glass and plastic films has been developed and investigated. There is the adsorption method for linear siloxane derivatives and strained cyclosiloxanes and the Langmuir‐Blodgette method. The physical properties (surface energy with polar and dispersion components and surface charge) of the films were studied as well as their ability to align liquid crystals (LCs). The OSC films have improved stability in ambient environments.
Split-2 Bisimilarity has a Finite Axiomatization over CCS with Hennessy's Merge
Authors: Aceto Luca , Fokkink Wan , Ingolfsdottir Anna , Luttik Bas
Published: July 2005

This note shows that split-2 bisimulation equivalence (also known as timed
equivalence) affords a finite equational axiomatization over the process
algebra obtained by adding an auxiliary operation proposed by Hennessy in 1981
to the recursion, relabelling and restriction free fragment of Milner's
Calculus of Communicating Systems. Thus the addition of a single binary
operation, viz. Hennessy's merge, is sufficient for the finite equational
axiomatization of parallel composition modulo this non-interleaving
equivalence. This result is in sharp contrast to a theorem previously obtained
by the same authors to the effect that the same language is not finitely based
modulo bisimulation equivalence.
Gate Dielectrics for Organic Field‐Effect Transistors: New Opportunities for Organic Electronics
Authors: Facchetti A. , Yoon M.‐H. , Marks T. J.
Published: July 2005

In this contribution we review the motivations for, and recent advances in, new gate dielectric materials for incorporation into organic thin‐film transistors (OTFTs) for organic electronics. After a general introduction to OTFT materials, operating principles, and processing requirements for optimizing low‐cost organic electronics, this review focuses on three classes of OTFT‐compatible dielectrics: i) inorganic (high‐k) materials; ii) polymeric materials; and iii) self‐assembled mono‐ and/multilayer materials. The principal goals in this active research area are tunable and reduced OTFT operating voltages, leading to decreased device power consumption while providing excellent dielectric/insulator properties and efficient low‐cost solution‐phase processing characteristics.
Electroactive Luminescent Self‐Assembled Bio‐organic Nanowires: Integration of Semiconducting Oligoelectrolytes within Amyloidogenic Proteins (Adv. Mater. 2005, 12, 1466)
Authors: Herland A. , Björk P. , Nilsson K. P. R. , Olsson J. D. M. , Åsberg P. , Konradsson P. , Hammarström P. , Inganäs O.
Published: July 2005

To view the original paper use http://dx.doi.org/10.1002/adma.200500183.
Inheritance pattern of Beckwith–Wiedemann syndrome is heterogeneous in 291 families with an affected proband
Authors: Wangler Michael F. , An Ping , Feinberg Andrew P. , Province Michael , DeBaun Michael R.
Published: July 2005

Beckwith–Wiedemann syndrome (BWS) is congenital disorder whose molecular etiology is related to genetic and epigenetic mutations on 11p15. The majority of cases of BWS are sporadic, but a substantial proportion are familial, with an unknown inheritance pattern, although autosomal dominant and sex‐dependent inheritance have been proposed. We tested the hypothesis that in familial BWS, autosomal dominant inheritance is the primary mode of transmission underlying familial instances. Segregation analysis was performed in 291 families ascertained with an affected child. Individuals were considered to have BWS if they had two of five major features: macroglossia, macrosomia, hypoglycemia at birth, abdominal wall defect, and ear pits or creases. Models of inheritance were tested using pedigree analysis package (PAP) parameterized for a discrete trait. A total of 291 families of an affected proband were included in the study. The analysis was based on a revised general model that included a boundary solution. Sporadic and environmental models were rejected. Overall, the results suggested Mendelian inheritance but under recessive or additive mode of inheritance, which fit the data equally well rather than dominant inheritance. However, the presence of families in the cohort consistent with dominant and sex‐dependent inheritance suggest familial BWS may be a heterogeneous group comprised of different inheritance patterns. Familial BWS does not appear to be consistent with autosomal dominant transmission, and is likely a complex mixture of different inheritance patterns. © 2005 Wiley‐Liss, Inc.
Cardiofaciocutaneous syndrome (CFC) with congenital peripheral neuropathy and nonorganic malnutrition: An autopsy study
Authors: Manci Elizabeth A. , Martinez Jose E. , Horenstein Marcelo G. , Gardner Todd M. , Ahmed Arsalan , Mancao Mary C. , Gremse David A. , Gardner David M. , Nimityongskul Prasit , Maertens Paul , Riddick Leroy , Kavamura Maria I.
Published: July 2005

Many phenotypic manifestations have been reported in cardiofaciocutaneous (CFC) syndrome, but none, to date, are pathognomonic or obligatory. Previous histopathological studies reported findings in skin and hair; no autopsy studies have been published. We report the clinical and autopsy findings of a 7‐year‐old boy with severe CFC syndrome and malnutrition of psychosocial origin. Manifestations of CFC, reported previously, included macrocephaly and macrosomia at birth; short stature; hypotonia; global developmental delays; dry, sparse thin curly hair; sparse eyebrows and eyelashes; dilated cerebral ventricles; high cranial vault; bitemporal constriction; supraorbital ridge hypoplasia; hypertelorism; ptosis; exophthalmos; depressed nasal bridge; anteverted nostrils; low‐set, posteriorly‐rotated, large, thick ears; decayed, dysplastic teeth; strabismus; hyperelastic skin; wrinkled palms; keratosis pilaris atrophicans faciei; ulerythema ophryogenes; hyperkeratosis; gastroesophageal reflux; and tracheobronchomalacia. Additional findings, not previously reported, include islet cell hyperplasia, lymphoid depletion, thymic atrophy and congenital hypertrophy of peripheral nerves with onion bulb formations. Although the islet cell hyperplasia, lymphoid depletion, and thymic atrophy are nonspecific findings that may be associated with either CFC or malnutrition, the onion bulb hypertrophy is specific for a demyelinating–remyelinating neuropathy. These findings implicate congenital peripheral neuropathy in the pathogenesis of the developmental delays, feeding difficulties, respiratory difficulties, ptosis and short stature in this case. Additional studies of other cases of CFC are needed. © 2005 Wiley‐Liss, Inc.
Epidemiologic characteristics of anophthalmia and bilateral microphthalmia among 2.5 million births in California, 1989–1997
Authors: Shaw Gary M. , Carmichael Suzan L. , Yang Wei , Harris John A. , Finnell Richard H. , Lammer Edward J.
Published: July 2005

There is a paucity of epidemiologic information about the eye malformations anophthalmia and microphthalmia. Using data from a large population‐based registry, we explored prevalences and maternal/infant characteristics associated with anophthalmia and bilateral microphthalmia. Data were derived from the California Birth Defects Monitoring Program, a population‐based active surveillance system for collecting information on infants and fetuses with congenital malformations using multiple source ascertainment. Approximately 2.5 million births (liveborn and stillborn) occurred during the ascertainment period, 1989–1997. Information on maternal and infant/fetal characteristics was obtained from California birth certificate and fetal death files. The prevalence per 10,000 livebirths and stillbirths for anophthalmia was 0.18 and for bilateral microphthalmia was 0.22. These estimates reflect prevalences among births without chromosomal anomalies. Relative risks of anophthalmia were modestly higher among women aged 40 or more (relative risk = 2.0, 95% confidence interval 0.5–8.6). Risks were substantially lower for those mothers with >12 years of education, even after adjusting for other study factors, relative risk = 0.6 (0.2–1.7). The risk of anophthalmia was approximately twofold among multiple births compared to singletons. Similar to results for anophthalmia, decreased risks for bilateral microphthalmia were observed for maternal education of 12 years or more and increased risks observed for multiple births. These data show descriptive epidemiologic features of anophthalmia and bilateral microphthalmia. © 2005 Wiley‐Liss, Inc.
Growth hormone benefits children with 18q deletions
Authors: Cody Jannine D. , Semrud‐Clikeman Margaret , Hardies L. Jean , Lancaster Jack , Ghidoni Patricia D. , Schaub Rebecca L. , Thompson Nora M. , Wells Lynda , Cornell John E. , Love Tanzy M. , Fox Peter T. , Leach Robin J. , Kaye Celia I. , Hale Daniel E.
Published: July 2005

Most individuals with constitutional deletions of chromosome 18q have developmental delays, dysmyelination of the brain, and growth failure due to growth hormone deficiency. We monitored the effects of growth hormone treatment by evaluating 23 individuals for changes in growth, nonverbal intelligence quotient (nIQ), and quantitative brain MRI changes. Over an average of 37 months, the treated group of 13 children had an average nIQ increase of 17 points, an increase in height standard deviation score of 1.7, and significant change in T1 relaxation times in the caudate and frontal white matter. Cognitive changes of this magnitude are clinically significant and are anticipated to have an effect on the long‐term outcomes for the treated individuals. © 2005 Wiley‐Liss, Inc.
Microdeletion in the SHOX 3′ region associated with skeletal phenotypes of Langer mesomelic dysplasia in a 45,X/46,X,r(X) infant and Leri–Weill dyschondrosteosis in her 46,XX mother: Implication for the SHOX enhancer
Authors: Fukami Maki , Okuyama Torayuki , Yamamori Shunji , Nishimura Gen , Ogata Tsutomu
Published: July 2005

It is known that SHOX nullizygosity results in Langer mesomelic dysplasia (LMD) and SHOX haploinsufficiency leads to Leri–Weill dyschondrosteosis (LWDC). Here, we report on a microdeletion in the SHOX 3′ region identified in a Japanese infant with LMD‐compatible skeletal features and a 45,X[191]/46,X,r(X)(p22.3q24)[9] karyotype and in her mother with LWDC‐compatible skeletal features and a normal 46,XX karyotype. Physical and auxological examinations revealed mesomelic appearance, ulnarly deviated hands, and borderline micrognathia in the infant, and relatively short forearms and lower legs in the mother. Radiological studies indicated mesomelia, markedly curved radii, hypoplastic ulnas and fibulas, and metaphyseal splaying in the infant, and borderline to mild curvature of the radii, decreased carpal angles, and high‐normal triangularization index in the mother. Cytogenetic and molecular studies showed that the ring X chromosome of the infant was missing SHOX and of paternal origin, whereas the cytogenetically normal X chromosomes of the infant and one of the two X chromosomes of the mother, though they retained SHOX with normal coding sequences, had a microdeletion in the SHOX 3′ region. The microdeletion started from a position ∼200 kb from SHOX coding sequences, and spanned 240–350 kb in physical length involving DXYS233. The results, in conjunction with those reported by Flanagan et al. [2002], suggest that a cis‐acting enhancer exists in the SHOX 3′ region around DXYS233. © 2005 Wiley‐Liss, Inc.
Plantar lipomatosis, unusual facies, and developmental delay: Confirmation of Pierpont syndrome
Authors: Oudesluijs Grétel G. , Hordijk Roel , Boon Maartje , Sijens Paul E. , Hennekam Raoul C.M.
Published: July 2005

In 1998, Pierpont et al. reported on two unrelated boys with plantar lipomatosis, unusual facial phenotype, and developmental delay as a possible new MR/MCA syndrome. Here we report on a 2‐year‐old boy with similar manifestations: axial hypotonia in the first few months, prolonged feeding problems, moderate developmental delay, no speech development, deep palmar and plantar grooves, fat pads at the anteromedial aspect of the heels, and a distinct facial phenotype (high forehead, high anterior hairline, mild midfacial hypoplasia, remarkably narrow and upward slanted palpebral fissures, broad nasal ridge and tip, broad philtrum, bowed upper lip, “pouting” lower lip, full cheeks, and flat occiput). Brain MRI and MR spectroscopy studies showed relatively small frontal lobes, some widening of the lateral and third ventricles, and increased choline levels in the frontal white matter. Cytogenetic studies in lymphocytes and skin fibroblasts and whole genome micro‐array CGH failed to show abnormalities. The present patient has a phenotype almost identical to that of the earlier reported children (Pierpont et al. [1998]: Am J Med Genet 75:18–21), which thereby validates this as a separate MR/MCA syndrome, appropriately designated Pierpont syndrome. The cause of the entity remains uncertain, the most likely etiologies being X‐linked recessive or autosomal dominant genes. © 2005 Wiley‐Liss, Inc.
Metathesereaktionen in der Totalsynthese
Authors: Nicolaou K. C. , Bulger Paul G. , Sarlah David
Published: July 2005

Mit Ausnahme der palladiumkatalysierten Kreuzkupplungsreaktionen hatte im vergangenen Vierteljahrhundert keine Reaktionsklasse einen derart weitreichenden Einfluss auf die Kohlenstoff‐Kohlenstoff‐Verknüpfung und die Totalsynthese wie die Metathesereaktionen von Olefinen, Eninen, und Alkinen. In diesem Aufsatz präsentieren wir Glanzlichter aus einer Reihe ausgewählter Totalsynthesen, in denen diese eleganten und effizienten Reaktionen entscheidend zum Erfolg beigetragen haben. Schon an ihrer kurzen, aber beeindruckenden Geschichte kann man ablesen, dass die Bedeutung dieser Reaktionen für die chemische Synthese weiter zunehmen wird.