bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphite Furnace Modification for Second Surface Atomization
Authors: Holcombe James A. , Sheehan Michael T.
Published: August 2005

Preliminary results from a simple furnace modification are presented. A graphite condensation site has been located inside a commercial graphite furnace atomizer. Solution samples are deposited on the furnace wall and the analyte and other condensible species “distilled” to this site during a high temperature ash. During the atomization cycle, the analyte is revaporized from the “plug” into the higher temperature furnace environment. The plug is radiatively heated and can lag behind the wall temperature by more than 1000 K, thus providing atomization into a higher temperature environment which is more nearly isothermal. The heating program with analyte transfer permits extremely high ash temperatures to be used and offers the possibility of separating the analyte from gaseous, thermal decomposition products from the matrix. Additionally, distortions of the analytical absorbance signal caused by degradation in the pyrolytic surface of the furnace are minimized when atomization from the secondary surface is employed. Limits of detection for Ag, Cr, Cu, Fe, Pb, Sn, and Zn are within a factor of 2 of values determined using wall atomization. Studies are presented on the interference of sulfate on Sn analysis. Improved peak height sensitivity and a decreased dependency on sulfate concentrations have been observed.
Diffuse Thickness as a Measure of Light Scattering
Authors: Birth Gerald S.
Published: August 2005

The concept of diffuse thickness was developed as an alternative method of measuring the light scattering in diffusely reflecting samples. It is defined as the minimum thickness of a diffusely reflecting and transmitting material required to produce complete diffusion. A series of liquid samples with varying concentrations of a green dye differed in light scattering by as much as 7:1 and in reflectance by 8:1. Results showed the diffuse thickness to be independent of absorption. In addition, the diffuse thickness was used with reflectance data to compute an absorption coefficient that correlated linearly with dye concentration despite the differences in light scattering ( r = 0.99896). Additional data obtained with samples in which the scattering was varied by changing the proportion of two types of particles showed that a different mathematical procedure was required to obtain an equivalent correlation.
Infrared Spectra of Some Substituted Monoazobenzenes, Hydroxyhydrazone Tautomerism in Orthohydroxy, and Orthoaminoazobenzenes
Authors: Afifi M. S. , Tera F. M. , Sayed A. M. B.
Published: August 2005

The infrared spectra of substituted monoazobenzenes (O-Cl, m-Cl, p-Cl, p-Br, 2,5-dichloro, O-NO2, m-NO2, p-NO2, and 2,4-dinitro) derived from p-hydroxy, O-aminobenzenes (series A), and of the substituted monoazobenzenes ( O-Cl, m-Cl, p-Cl, 2,5-dichloro, p-Br, and O-NO2) derived from p-amino, O-hydroxybenzene (series B) have been recorded and tentatively assigned. In series A the O-NO2, m-NO2, and 2,4-dinitro compounds and all members of series B show a relatively intense IR band at 1651 ± 17 cm−1. The appearance of this band in the nitrocompounds of series A at 1654 ± 14 cm−1 is interpreted as being probably due to coupling of ΔNH2 and α as NO2. The band at 1642 ± 8 cm−1 in series B is tentatively as signed as a ν C=O absorption. This interpretation is regarded as evidence of tautomeric equilibrium in series B of these azodyes.
Infrared Photothermal Beam Deflection Fourier Transform Spectroscopy of Solids
Authors: Low M. J. D. , Lacroix M. , Morterra C.
Published: August 2005

Infrared spectra were recorded of organic and inorganic solids with a Fourier transform spectrometer built to operate with a photothermal beam deflection detector. No sample preparation or cells per se is needed to examine milligram quantities of powder. The total absence of sample-containing devices makes it possible to examine portions of the surfaces of objects which are very large in size. Sample heating may occur, so that care must be taken with heat-sensitive materials.
Noise Reduction via Factor Analysis in FT-IR Spectra
Authors: Gillette P. C. , Koenig J. L.
Published: August 2005

The application of factor analysis to reduce random noise in FT-IR spectra is described. By utilizing the total information content of all the spectra, it is possible to reduce the amount of random noise present in individual spectrum.
ICP Emission Spectra: II. Alkaline Earth Elements
Authors: Anderson T. A. , Forster A. R. , Parsons M. L.
Published: August 2005

The spectra originating from an ICP excitation source operated under a standard set of conditions were classified and tabulated for the alkaline earth elements. The spectra were acquired by means of a scanning, echelle monochromator capable of measuring wavelength position to 0.01 Å. The spectral range observed was 2075 to 6005 Å. Almost all expected transitions for both atomic and singly ionized species in this spectral range were observed. The nature of this spectra is discussed. Several transitions are reported which were not in the MIT Tables.
Effects of Laser Linewidth on the Coherent Anti-Stokes Raman Spectroscopy Spectral Profile
Authors: Kataoka Haruhiko , Maeda Shiro , Hirose Chiaki
Published: August 2005

The expression for the intensity in coherent anti-Stokes Raman spectroscopy (CARS) was derived for scanning CARS by taking into account the linewidths and phase relation of the two laser beams, and simulation procedures suited for practical applications were developed. The CARS spectra of p-xylene and N2 gas were observed, and the results were compared with the simulation curves based on two extreme cases of the statistical property of the laser source. It was shown that the effect of laser linewidth becomes remarkable when the Raman linewidth is comparable to or smaller than the laser linewidth, and that the degree of coherence among the frequency components within the laser linewidth is an important factor in determining the spectral profile.
Nuclear Magnetic Resonance Studies of Substituted 4-Hydroxy-5-phosphinyl-2-imidazolidinones
Authors: Mikroyannidis John A. , Tsolis Alexandros K.
Published: August 2005

The proton nuclear magnetic resonance (NMR) spectra of some substituted 4-hydroxy-5-phosphinyl-2-imidazolidinones have been studied. The predominance of the cis stereoisomer of these compounds has been also established by 1H NMR spectroscopy. The spectral effects produced by the introduction of the phosphinyl group on the parent compound and by reaction of the substituted 4-hydroxy-5-phosphinyl-2-imidazolidinones with aqueous sodium deuteroxide are discussed. In addition, it has been established by 1H NMR that the product obtained from the reaction of 2-hydroxy-2-(diethoxyphosphinyl)ethanal with N-methylurea was a mixture of 18.2% 1-methyl- and of 81.8% 3-methyl-4-hydroxy-5-diethoxyphosphinyl-2-imidazolidinone.
Infrared Studies of Styrene-Acrylic Acid and Styrene-Acrylamide Copolymers at Variable Temperature
Authors: Nyquist R. A. , Platt A. E. , Priddy D. B.
Published: August 2005

Changes in the physical properties of these copolymers at variable temperature are explained on the basis of change in the intermolecular structure as determined by application of infrared spectroscopy.
In Situ Analysis of Fluorinated Gases in Plasma Etching by Infrared Spectroscopy
Authors: Poll H. U. , Hinze D. , Schlemm H.
Published: August 2005

Infrared absorption spectroscopy proves to be a useful tool in the evaluation of plasma chemical conversions of etch gas mixtures during plasma etching for microelectronics. The partial pressures of the various perfluorinated gas components are obtained from infrared spectra with sufficient accuracy and may yield information about the actual state of the system. Methods of spectra recording and partial pressure computation are discussed. To demonstrate the applicability of the method, the conversions of CF4 + O2, and C2F4 in a glow discharge are investigated.
Fourier Transform Infrared Spectroscopy of Protein Adsorption from Whole Blood: II. Ex Vivo Sheep Studies
Authors: Winters S. , Gendreau R. M. , Leininger R. I. , Jakobsen R. J.
Published: August 2005

The adsorption of proteins from ex vivo flowing sheep blood has been studied using FT-IR/ATR with spectra being collected at 0.8-s intervals of blood flow. We have found that protein adsorption can be divided into four adsorption regions: the first region being one of rapid adsorption of protein species such as albumin, an unknown protein species, glycoproteins, and some fibrinogen; in the second region, there is little increase in the total protein adsorbed, but there is evidence of protein replacement. Fibrinogen adsorption is the major event occurring in the third adsorption region, whereas the appearance of red blood cells and platelets marks the fourth region. Such knowledge of protein composition at various times in the adsorption process is providing molecular level information on thrombosis occurring on surfaces.
Characterization of Catalytic Supports by Infrared Spectroscopy and ESCA
Authors: Wieserman Larry F. , Hercules David M.
Published: August 2005

This study compares the properties of γ-alumina, silica, and titania using ESCA and in situ FT-IR. The FWHM's of the O1s and metal 2p ESCA peaks increased systematically from titania to γ alumina; the O1s/metal 2p ESCA peak area ratios were nearly equal for γ-alumina and silica. For titania, however, the value was half that obtained for γ-alumina. In situ FT-IR showed hydroxyl bands with increasing frequencies from titania to silica. Alumina and titania form carbonate-type structures after exposure to CO at elevated temperatures. Silica exhibited no additional bands after CO treatment that could be assigned to physically adsorbed CO or carbonate-type structures. At 100°C, there is a direct correlation between the specific surface area and the intensity of infrared absorbance of the free-hydroxyl and the hydrogen-bonded hydroxyl bands for silica. The intensities of the infrared bands due to matrix modes were not affected by surface area.
Analysis of Polycyclic Aromatic Compounds Containing Nitrogen and Oxygen by Matrix Isolation Fourier Transform Infrared Spectroscopy
Authors: Garrison A. A. , Mamantov G. , Wehry E. L.
Published: August 2005

Matrix isolation sampling techniques are used in the qualitative and quantitative analysis of polar aromatic hydrocarbons. Fourier transform infrared spectrometry is used to characterize pure compounds isolated in nitrogen matrices and subsequently to identify individual components in mixtures. Compounds studied are polycyclic aromatic hydrocarbons containing nitrogen and oxygen heteroatoms or amine substituent groups. These toxic substances are common to coal liquefaction products. The analytical method chosen, matrix isolation Fourier transform infrared spectrometry, is capable of distinguishing between isomers differing only in the position of the heteroatom. Beer's law is obeyed in the range between 20 μg and 500 ng.
Fluorometric Properties of N-Methyltetraphenylporphine and Several Derivatives: Evaluation as Standards for Determination of Chlorophyll Concentrations
Authors: Lavallee David K. , McDonough Thomas J. , Cioffi Lisa
Published: August 2005

As part of an ongoing study of the chemistry and properties of N-methylporphyrins and their metal complexes, we have observed that the excitation and emission spectra of N-methyltetraphenylporphyrin and N-methyltetra( p-sulfophenyl)porphyrin and their zinc complexes closely resemble corresponding spectra of chlorophyll a. We have characterized fluorescence spectra for these species in a variety of solvents commonly used for quantitative determination of chlorophylls. Quantum yields for the N-methylporphyrins are lower by approximately a factor of 10 than yields for chlorophyll a in such solvents as acetone, ethanol, and mixed aqueous/organic solvent systems. The yields are quite sufficient, however, for these species to be used as fluorescence standards. Solution of N-methylporphyrins are stable and the compounds can be inexpensively synthesized in high purity. The tetra( p-sulfophenyl) species are soluble in aqueous and highly polar organic solvents, whereas the tetraphenyl species are soluble in nonpolar organic solvents.
Band Shape Analysis of Fourier Transform Infrared Spectra
Authors: Gillette P. C. , Lando J. B. , Koenig J. L.
Published: August 2005

The application of a finite difference Levenberg-Marquardt nonlinear least-squares procedure for the resoluton of overlapping peaks in Fourier transform-infrared spectra is described. Starting estimates of peak parameters utilized in the refinement are obtained from a numerically approximated second derivative spectrum which has been smoothed. Quantitative information reflecting the constituent peaks and the “goodness of fit” is displayed graphically in a procedure requiring much less than 1 min to both initiate and obtain results in a form that is readily interpreted.
Infrared and Photoacoustic Spectroscopic Studies of a Silica-Immobilized β-Diketone
Authors: Kendall D. S. , Leyden D. E. , Burggraf L. W. , Pern F. J.
Published: August 2005

Infrared and photoacoustic spectroscopies have in combination produced useful information about an immobilized β-diketone, formed by the reaction of acetylacetone with p-chloromethylphenyltrimethoxysilane previously immobilized on silica. Evidence confirming the synthesis of immobilized 3-benzyl-2,4-pentanedione is presented. Comparisons with 3-benzyl-2,4-pentanedione, a model for the surface bonded ligand, were valuable. The bound β-diketone is largely in the keto tautomer on the surface. The photoacoustic spectrum shows that the remainder is in the form of an intermolecular hydrogen-bonded enol. In basic solution the enolate ion and metal-enolate complexes can be formed. Infrared spectra show that the keto form can bind metals in acidic solutions.
Genetic Mapping of Species Boundaries in Louisiana Irises UsingIRRERetrotransposon Display Markers
Authors: Bouck Amy , Peeler Ryan , Arnold Michael L , Wessler Susan R
Published: August 2005

Genetic mapping studies provide insight into the pattern and extent of genetic incompatibilities affecting hybridization between closely related species. Genetic maps of two species of Louisiana Irises, Iris fulva and I. brevicaulis, were constructed from transposon-based molecular markers segregating in reciprocal backcross (BC1) interspecific hybrids and used to investigate genomic patterns of species barriers inhibiting introgression. Linkage mapping analyses indicated very little genetic incompatibility between I. fulva and I. brevicaulis in the form of map regions exhibiting transmission ratio distortion, and this was confirmed using a Bayesian multipoint mapping analysis. These results demonstrate the utility of transposon-based marker systems for genetic mapping studies of wild plant species and indicate that the genomes of I. fulva and I. brevicaulis are highly permeable to gene flow and introgression from one another via backcrossing.
A Genetic Screen Targeting the Tumor Necrosis Factor/Eiger Signaling Pathway: Identification of Drosophila TAB2 as a Functionally Conserved Component
Authors: Geuking Peter , Narasimamurthy Rajesh , Basler Konrad
Published: August 2005

Signaling by tumor necrosis factors (TNFs) plays a prominent role in mammalian development and disease. To fully understand this complex signaling pathway it is important to identify all regulators and transduction components. A single TNF family member, Eiger, is encoded in the Drosophila genome, offering the possibility of applying genetic approaches for pursuing this goal. Here we present a screen for the isolation of novel genes involved in the TNF/Eiger pathway. On the basis of Eiger's ability to potently activate Jun-N-terminal kinase (JNK) and trigger apoptosis, we used the Drosophila eye to establish an assay for dominant suppressors of this activity. In a large-scale screen the Drosophila homolog of TAB2/3 (dTAB2) was identified as an essential component of the Eiger-JNK pathway. Genetic epistasis and biochemical protein-protein interaction assays assign an adaptor role to dTAB2, linking dTRAF1 to the JNKKK dTAK1, demonstrating a conserved mechanism of TNF signal transduction in mammals and Drosophila. Thus, in contrast to morphogenetic processes, such as dorsal closure of the embryo, in which the JNK pathway is activated by the JNKKK Slipper, Eiger uses the dTAB2-dTAK1 module to induce JNK signaling activity.
The Ama1-Directed Anaphase-Promoting Complex Regulates the Smk1 Mitogen-Activated Protein Kinase During Meiosis in Yeast
Authors: McDonald Christine M , Cooper Katrina F , Winter Edward
Published: August 2005

Smk1 is a meiosis-specific MAPK homolog in Saccharomyces cerevisiae that regulates the postmeiotic program of spore formation. Similar to other MAPKs, it is activated via phosphorylation of the T-X-Y motif in its regulatory loop, but the signals controlling Smk1 activation have not been defined. Here we show that Ama1, a meiosis-specific activator of the anaphase-promoting complex/cyclosome (APC/C), promotes Smk1 activation during meiosis. A weakened allele of CDC28 suppresses the sporulation defect of an ama1 null strain and increases the activation state of Smk1. The function of Ama1 in regulating Smk1 is independent of the FEAR network, which promotes exit from mitosis and exit from meiosis I through the Cdc14 phosphatase. The data indicate that Cdc28 and Ama1 function in a pathway to trigger Smk1-dependent steps in spore morphogenesis. We propose that this novel mechanism for controlling MAPK activation plays a role in coupling the completion of meiosis II to gamete formation.
Systemic Suppression of the Contact Hypersensitivity by the Products of Protoporphyrin IX Photooxidation
Authors: Kyagova Alla A. , Mansurova Galina V. , Kozir Lyudmila A. , Ponomarev Gelii V. , Pavlov Vsevolod Y. , Konstantinov Igor O. , Ya. Potapenko Alexander
Published: August 2005

Photodynamic therapy (PDT) is frequently accompanied by induction of systemic immunosuppression. Photochemical mechanisms underlying this effect are not completely understood. Here, we demonstrate the immunosuppressive activity of photooxidation products of protoporphyrin IX dimethyl ester (PPIX) in a murine model of contact hypersensitivity (CHS) to 2,4‐dinitrofluorobenzene (DNFB). Intravenous injection of the preirradiated solution of PPIX to mice resulted in fluence‐dependent suppression of the CHS. The samples of photodecomposed PPIX with suppressive effect on the CHS contained chlorin‐type products, namely, two isomers of photoprotoporphyrin (pPP1 and pPP2) as main photoproducts. Concentration‐dependent suppression of the CHS was also induced when purified pPP1 or pPP2 were injected to mice intravenously. These purified photoproducts exerted equal immunosuppressive activity. The highest suppression of the CHS was induced when pPP1 was injected 20 h before sensitization with DNFB. The lowest suppression was at its injection time 24 h before challenge. The pPP1‐induced suppression of the CHS was adoptively transferable and was associated with generation of cells with suppressive functions. These suppressor cells inhibited the efferent phase of the CHS. Our results strongly indicate that induction of systemic immunosuppression by PDT with PPIX may proceed through photobleaching of photosensitizer and generation of photoprotoporphyrins, which can affect T cell immunity.
Inside Front Cover: Self‐Assembled Highly Faceted Wurtzite‐Type ZnS Single‐Crystalline Nanotubes with Hexagonal Cross‐Sections (Adv. Mater. 16/2005)
Authors: Yin L.‐W. , Bando Y. , Zhan J.‐H. , Li M.‐S. , Golberg D.
Published: August 2005

Highly faceted wurtzite‐type ZnS nanotubes with hexagonal cross‐section morphologies have been self‐assembled via a controllable high‐temperature thermal‐chemical reaction route in work reported by Yin and co‐workers on p. 1972. The self‐assembly growth along c‐axis to highly hexagonal‐faceted ZnS single‐crystalline nanotubes is associated with the crystallographic characteristics, such as the non‐central and polar surfaces of the wurtzite‐type ZnS structure. The faceted ZnS nanotubes grow along the <0001> direction, and are closed by low‐index faces of non‐polar {1000} faces. The inside cover and insets show electron microscopy and scanning electron microscopy images of the faceted ZnS nanotubes.
A patient with mosaic partial trisomy 18 resulting from dicentric chromosome breakage
Authors: Morrissette Jennifer J.D. , Medne Livija , Bentley Tyrone , Owens Nancy L. , Geiger Elizabeth , Pipan Mary , Zackai Elaine H. , Shaikh Tamim , Spinner Nancy B.
Published: August 2005

We present a patient with minor dysmorphic features and a mosaic karyotype with two different abnormal cell lines, both involving abnormalities of chromosome 18. Twenty percent of cells studied (4/20) had 46 chromosomes with a large derivative pseudoisodicentric chromosome 18. This chromosome was deleted for 18pter and duplicated for part of proximal 18p (18p11.2 based on fluorescence in situ hybridization (FISH) studies and all of 18q. The two copies of portions of chromosome 18 were fused in an inverted fashion (duplicated for 18qter‐>18p11.3). The smaller der(18) was present in 80% of cells studied (16/20) and had a normal q‐arm, while the p‐arm was missing the subtelomere region but had duplication of a part of 18p. FISH studies showed that the larger derivative 18 contained the 18q subtelomere at each end, but the 18p subtelomere was absent, consistent with fusion of two regions within 18p resulting in deletion of the subtelomeric regions. The smaller der(18) was also missing the 18p subtelomere (with normal 18q as expected). Further testing with BAC clones mapping within 18p11.2 showed that these sequences were duplicated and inverted in both of the der(18)s. These findings lead us to hypothesize that the smaller der(18) was derived from the larger, dicentric 18 following anaphase bridge formation, with breakage distal to the duplicated segment. © 2005 Wiley‐Liss, Inc.
Family‐based association study of serotonin transporter gene polymorphisms in attention deficit hyperactivity disorder: No evidence for association in UK and Taiwanese samples
Authors: Xu Xiaohui , Mill Jonathan , Chen Chi‐Ken , Brookes Keeley , Taylor Eric , Asherson Philip
Published: August 2005

Five independent studies have reported associations between serotonin transporter gene (5‐HTT) polymorphisms and attention deficit hyperactivity disorder (ADHD). Four studies found evidence for association between the long‐allele of a 44‐base pair insertion/deletion polymorphism (5‐HTTLPR), one of the studies found association to a variable number tandem repeat within intron 2, another to the T‐allele of a single base pair substitution in the 3′‐untranslated regions and another reported preferential transmission of a haplotype of the three markers (long‐allele/10‐repeat‐allele/T‐allele). One further study found no evidence for these associations. We investigated the association of these three markers in two samples of ADHD patients from the United Kingdom (n = 197) and Taiwan (n = 212), using within‐family tests of association. No association was found between any of the three markers in either of the two populations. Although we found some evidence for the preferential transmission of a rare haplotype (long‐allele/9‐repeat‐allele/T‐allele; χ2 = 4.5,P = 0.034), we concluded that this most likely occurred by chance factors alone. © 2005 Wiley‐Liss, Inc.
Neuregulin‐1 polymorphism in late onset Alzheimer's disease families with psychoses
Authors: Go Rodney C. P. , Perry Rodney T. , Wiener Howard , Bassett Susan S. , Blacker Deborah , Devlin Bernie , Sweet Robert A.
Published: August 2005

Probands with late onset Alzheimer's disease (LOAD) exhibit positive symptoms of psychosis, 30–60% of the time. Positive symptoms of psychosis have been shown to appear prior to the onset of dementia to be accompanied by greater cognitive deficits, and to predict a more rapid decline. A study of the distribution of AD with psychosis (ADP) in families from the NIMH Alzheimer's Disease Genetic Initiative sample indicates that the trait is heritable, and linkage studies of multiplex ADP families have found suggestive peaks on 2p, 6q, 8p, and 21q. A genome scan of idiopathic psychosis, schizophrenia, in the Icelandic population identified a risk haplotype within the 5′ region of neuregulin‐1 (NRG1) on 8p12. Associations with NRG1 SNPs have also been found in other schizophrenia populations from Scotland, Ireland, and China. Here, we report results demonstrating a significant linkage peak for ADP on 8p12 in the NIMH AD dataset, encompassing the NRG1 region. We also demonstrate that there is a significant association with a NRG1 SNP (single nucleotide polymorphism), rs392499, with ADP, χ2 = 7.0, P = 0.008. This same SNP is part of a 3‐SNP haplotype preferentially transmitted to individuals with this phenotype. Our results suggest that NRG1 plays a role in increasing the genetic risk to positive symptoms of psychosis in a proportion of LOAD families. © 2005 Wiley‐Liss, Inc.
Morphology, thermal stability, and dynamic mechanical properties of atactic polypropylene/carbon nanotube composites
Authors: Yang Jun , Lin Yuhan , Wang Jinfeng , Lai Mingfang , Li Jing , Liu Jingjiang , Tong Xin , Cheng Huiming
Published: August 2005

Nanocomposites based on atactic polypropylene (aPP) and multiwall carbon nanotubes were prepared by melt blending at 80°C with a Barabender mixer. The morphology, thermal stability, and dynamic mechanical properties of the obtained composites were studied subsequently. SEM observations indicate that the nanotubes are well dispersed in the aPP matrix. Each nanotube is covered by a layer of aPP molecules. Thermal stability of the aPP in nitrogen is found to be enhanced significantly by the addition of nanotubes. Peak temperature of the DTG curve for the nanocomposite with 5 wt % nanotube loading shows about 70°C higher than that of pure aPP. Dynamic mechanical properties of aPP are also influenced by nanotubes, as shown by the increase in the storage modulus as well as significantly broadened loss tanδ peak. These effects of nanotubes on the thermal stability and mechanical properties of aPP are explained by the adsorption effect of the aPP molecules on the nanotube surfaces in this study. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1087–1091, 2005
Characterization of optical properties of acrylate based adhesives exposed to different temperature conditions
Authors: Priyadarshi A. , Shimin L. , Mhaisalkar S. G. , Rajoo R. , Wong E. H. , Kripesh V. , Namdas E. B.
Published: August 2005

Optical adhesives combine the traditional function of structural attachment with a more advanced function of providing an optical path between optical interconnects. This article aims to characterize refractive index and birefringence of such adhesives under environmental exposure to different temperature conditions. Optical time domain reflectometery (OTDR) and prism coupling methods were employed to measure optical properties of an optical adhesive. Thermo‐optic coefficient (dn/dT) of the adhesive was observed to decrease noticeably from −2 × 10−4°C−1 to −4 × 10−4°C−1 around the glass transition temperature (Tg ∼ 78°C). It is observed that refractive indices for both TE and TM modes increase with increasing annealing temperature, but the birefringence (TE − TM) is decreasing. This suggests that the material has become more isotropic due to the annealing. The environmental changes in optical properties of the adhesive are discussed in the light of Lorentz–Lorenz equations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 950–956, 2005
Single wall carbon nanotube dispersion and exfoliation in polymers
Authors: Uchida Tetsuya , Kumar Satish
Published: August 2005

Dispersion and exfoliation of single wall carbon nanotubes (SWNTs) have been studied in poly(acrylonitrile) (PAN), poly(p‐phenylene benzobisoxazole) (PBO) solutions, and composite fibers using transmission electron microscopy. As a result of polymer assisted dispersion and exfoliation, the average SWNT bundle diameter in SWNT/PAN (5/95) was 11 nm, while the average diameter for the pristine SWNT bundles was about 30 nm. High resolution TEM of SWNT/PBO (10/90) composite fibers did not reveal the presence of SWNT aggregates or bundles, suggesting SWNT exfoliation as individuals. On the other hand, both oriented and unoriented nanotube bundles have been observed in SWNT/PBO samples containing 15 wt % nanotubes. Carbon nanotubes are 105 times more radiation resistant than flexible polymers such as polyethylene, and 103 times more resistant than highly radiation resistant polymers such as PBO. Therefore in the high resolution TEM study of nanotube/polymer composites, nanotubes can be observed long after the polymer has been damaged by electron radiation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 985–989, 2005
Development of a fast drying hybrid lacquer in a low‐relative‐humidity environment based on kurome lacquer sap
Authors: Lu Rong , Ishimura Takahisa , Tsutida Katsuya , Honda Takayuki , Miyakoshi Tetsuo
Published: August 2005

Hybrid lacquers that dry quickly in a low‐relative‐humidity environment were synthesized with the repeated kurome lacquer process and an organic silicone compound. An investigation by gel permeation chromatography showed that fractions with different molecular weights showed a lower monomer concentration than the pure kurome lacquer. Fourier transform infrared spectra of the hybrid lacquers revealed that absorption due to the ether of the quinone olefin and/or dibenzofuran appeared around 1470 and 1080 cm−1 and increased with the number of drying days. The gel fractions in the lacquer films increased according to the number of drying days, and this showed that the hybrid lacquers had higher gel fractions than the pure kurome lacquer in the initial stage of dryness. In addition, the drying mechanism of the hybrid lacquers was analyzed with an automatic drying time recorder and rigid‐body pendulum physical property testing measurements. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1055–1061, 2005
Rheological properties of styrene‐co‐2‐furfuryl methacrylate copolymers
Authors: Rego Jose M. , Berglund Charles , Welsh Gary , White Michael
Published: August 2005

The copolymerization of styrene with furfuryl methacrylate (FMA) led to a very significant molecular weight increase and to branching, as measured by standard gel permeation chromatography (GPC) and tri‐angle laser light‐scattering GPC. This increase was also confirmed by dynamic mechanical spectroscopy. Extensional viscosity analysis showed that styrene‐co‐2‐furfuryl methacrylate copolymers exhibited strain hardening at low strain rates. This strain hardening is explained as a result of the copolymers' polydispersity features rather than a result of their topology. The presence of strain hardening in extensional viscosity experiments is believed to be advantageous in the production of foamed materials with lower densities. A reduction in density was corroborated by foaming experiments on a development extrusion line. The mechanism of density lowering was related more to cell growth than to increased nucleation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1062–1071, 2005
Synthesis and characterization of epoxy based nanocomposites
Authors: Basara Cigdem , Yilmazer Ulku , Bayram Goknur
Published: August 2005

Epoxy‐clay nanocomposites were synthesized to examine the effects of the content and type of different clays on the structure and mechanical properties of the nanocomposites. Diglycidyl ether of bisphenol‐A (epoxy) was reinforced by 0.5–11 wt % natural (Cloisite Na+) and organically modified (Cloisite 30B) types of montmorillonite. SEM results showed that as the clay content increased, larger agglomerates of clay were present. Nanocomposites with Cloisite 30B exhibited better dispersion and a lower degree of agglomeration than nanocomposites with Cloisite Na+. X‐ray results indicated that in nanocomposites with 3 wt % Cloisite 30B, d‐spacing expanded from 18.4 Å (the initial value of the pure clay) to 38.2 Å. The glass transition temperature increased from 73°C, in the unfilled epoxy resin, to 83.5°C in the nanocomposite with 9 wt % Cloisite 30B. The tensile strength exhibited a maximum at 1 wt % modified clay loading. Addition of 0.5 wt % organically modified clay improved the impact strength of the epoxy resin by 137%; in contrast, addition of 0.5 wt % unmodified clay improved the impact strength by 72%. Tensile modulus increased with increasing clay loading in both types of nanocomposites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1081–1086, 2005
Metrics for the scope of a collection
Authors: Allen Robert B. , Wu Yejun
Published: August 2005

Some collections cover many topics, while others are narrowly focused on a limited number of topics. We introduce the concept of the “scope” of a collection of documents and we compare two ways of measuring it. These measures are based on the distances between documents. The first uses the overlap of words between pairs of documents. The second measure uses a novel method that calculates the semantic relatedness to pairs of words from the documents. Those values are combined to obtain an overall distance between the documents. The main validation for the measures compared Web pages categorized by Yahoo. Sets of pages sampled from broad categories were determined to have a higher scope than sets derived from subcategories. The measure was significant and confirmed the expected difference in scope. Finally, we discuss other measures related to scope.
Measuring short‐ and long‐run promotional effectiveness on scanner data using persistence modelling
Authors: Dekimpe Marnik G. , Hanssens Dominique M. , Nijs Vincent R. , Steenkamp Jan‐Benedict E. M.
Published: August 2005

The use of price promotions to stimulate brand and firm performance is increasing. We discuss how (i) the availability of longer scanner data time series, and (ii) persistence modelling, have lead to greater insights into the dynamic effects of price promotions, as one can now quantify their immediate, short‐run, and long‐run effectiveness. We review recent methodological developments, and illustrate how the analysis of numerous brands and product categories has resulted in various empirical generalizations. Finally, we argue that persistence modelling should not only be applied to traditional performance metrics such as sales, but also to metrics such as firm value and customer equity. Copyright © 2005 John Wiley & Sons, Ltd.
Genotype–phenotype relationships in an investigation of the role of proteases in abdominal aortic aneurysm expansion
Authors: Eriksson P , Jormsjö-Pettersson S , Brady A R , Deguchi H , Hamsten A , Powell J T
Published: August 2005

Background

The aim of the study was to investigate the effect of functional polymorphisms in promoters of matrix metalloproteinase (MMP) 2, MMP-3, MMP-9, MMP-12 and plasminogen activator inhibitor (PAI) 1 genes on the growth rate of small abdominal aortic aneurysms (AAA).

Methods

Some 455 individuals with a small AAA (4·0–5·5 cm) were monitored for aneurysm growth by ultrasonography (mean follow-up 2·6 years). They also provided a DNA sample for analysis of the −1306 C > T, −1171 5A > 6A, −1562 C > T, −82 A > G and −675 4G > 5G alleles of MMP-2, MMP-3, MMP-9, MMP-12 and PAI-1, respectively. Mean linear AAA growth rates were calculated by flexible modelling; the sample size was sufficient to detect variants that influenced the growth rate by 25 per cent.

Results

For MMP-2, MMP-9 and MMP-12 genotypes, growth rates were similar to the mean linear growth rate of 3·08 mm per year. For MMP-3, growth rates were 3·05 (for 5A5A), 3·19 (for 5A6A) and 2·90 (for 6A6A) mm per year. For PAI-1, patients with 4G4G, 4G5G and 5G5G genotypes had growth rates of 3·18, 2·92 and 3·47 mm per year, respectively, for aneurysms with a baseline diameter of 45·1, 44·6 and 46·2 mm. The increased growth rate for patients with PAI-1 5G5G genotype was not statistically significant (P = 0·061), although these patients had the lowest plasma PAI-1 concentrations (P = 0·018).

Conclusion

There was no evidence that any specific MMP polymorphism had a clinically significant effect on AAA expansion. The plasminogen system may have a small but clinically significant role in AAA development. Much larger studies would be needed to evaluate genes of smaller effect.
Nonlinear optical spectroscopy of chiral molecules
Authors: Fischer Peer , Hache François
Published: August 2005

We review nonlinear optical processes that are specific to chiral molecules in solution and on surfaces. In contrast to conventional natural optical activity phenomena, which depend linearly on the electric field strength of the optical field, we discuss how optical processes that are nonlinear (quadratic, cubic, and quartic) functions of the electromagnetic field strength may probe optically active centers and chiral vibrations. We show that nonlinear techniques open entirely new ways of exploring chirality in chemical and biological systems: The cubic processes give rise to nonlinear circular dichroism and nonlinear optical rotation and make it possible to observe dynamic chiral processes at ultrafast time scales. The quadratic second‐harmonic and sum‐frequency‐generation phenomena and the quartic processes may arise entirely in the electric‐dipole approximation and do not require the use of circularly polarized light to detect chirality. They provide surface selectivity and their observables can be relatively much larger than in linear optical activity. These processes also give rise to the generation of light at a new color, and in liquids this frequency conversion only occurs if the solution is optically active. We survey recent chiral nonlinear optical experiments and give examples of their application to problems of biophysical interest. © 2005 Wiley‐Liss, Inc. Chirality 17:421–437, 2005.
Ab initio Studies of ClOx Reactions: Prediction of the Rate Constants of ClO+NO2 for the Forward and Reverse Processes
Authors: Zhu R. S. , Lin M. C.
Published: August 2005

The potential‐energy surface for the reaction of ClO with NO2 has been constructed at the CCSD(T)/6‐311+G(3df)//B3LYP/6‐311+G(3df) level of theory. Six ClNO3 isomers are located; these are ClONO2, pc‐ClOONO, pt‐ClOONO, OClNO2, pt‐OClONO, pc‐OClONO, with predicted energies relative to the reactants of −25.6, −0.5, 1.0, 1.9, 12.2 and 13.6 kcal mol−1, and heats of formation at 0 K of 7.8, 32.9, 34.4, 35.5, 45.6 and 47.0 kcal mol−1, respectively. Isomerizations among them are also discussed. The rate constants for the low‐energy pathways have been computed by statistical theory calculations. For the association reaction producing exclusively ClONO2, the predicted low‐ and high‐pressure‐limit rate constants in N2 for the temperature range of 200–600 K can be represented by: ${{\rm{k}}_1^0 }$(N2)=3.19×10−17 T−5.54 exp(−384 K/T) cm6 molecule−2 s−1 and ${{\rm{k}}_1^\infty }$=3.33×10−7 T−1.48 exp(−18 K/T) cm3 molecule−1 s−1. The predicted low‐ and high‐pressure‐limit rate constants for the decomposition of ClONO2 in N2 at 200–600 K can be expressed, respectively, by ${{\rm{k}}_{ - 1}^0 }$=6.08×1013 T−6.54 exp(−13813 K/T) cm3 molecule−1 s−1 and ${{\rm{k}}_{ - 1}^\infty }$=4.59×1023 T−2.43 exp(−13437 K/T) s−1. The predicted values compare satisfactorily with available experimental data. The reverse Cl+NO3 reaction was found to be independent of the pressure, giving exclusively ClO+NO2; the predicted rate constant can be expressed as k(Cl+NO3)=1.19×10−9 T−0.60 exp(58 K/T) cm3 molecule−1 s−1.
Hydrophobic–Hydrophilic Interactions of Water with Alkanethiolate Chains from First‐Principles Calculations
Authors: Silvestrelli Pier Luigi , Ancilotto Francesco , Toigo Flavio , Sbraccia Carlo , Ikeda Takashi , Boero Mauro
Published: August 2005

The interaction of water with alkanethiolate chains is studied from first principles. A detailed analysis is performed by optimizing the structure of small water clusters, one‐dimensional water chains, and ordered and disordered thin water layers adsorbed on hydroxyl(OH)‐ and methyl(CH3)‐terminated alkanethiol monolayers. The hydrophilic/hydrophobic character of these two different substrates is investigated by means of an energetic analysis combined with hydrogen‐bond counting. On the hydrophilic OH‐terminated alkanethiol surface, zigzag, one‐dimensional water chains and disordered thin water layers are the energetically favored structures. The ab initio results can be used to determine the optimal value of the empirical parameters characterizing a suitable force field to be used in classic molecular dynamics simulations.
Photophysical Characterization of Light‐Emitting Poly(indenofluorene)s
Authors: Keivanidis Panagiotis E. , Jacob Josemon , Oldridge Luke , Sonar Prashant , Carbonnier Benjamin , Baluschev Stanislav , Grimsdale Andrew C. , Müllen Klaus , Wegner Gerhard
Published: August 2005

Time‐resolved photoluminescence spectroscopy experiments of three poly(2,8‐indenofluorene) derivatives bearing different pendant groups are presented. A comparison of the photophysical properties of dilute solutions and thin films provides information on the chemical purity of the materials. The photophysical properties of poly(2,8‐indenofluorene)s are correlated with the morphological characteristics of their corresponding films. Wide‐angle X‐ray scattering experiments reveal the order in these materials at the molecular level. The spectroscopic results confirm the positive impact of a new synthetic approach on the spectral purity of the poly(indenofluorene)s. It is concluded that complete side‐chain substitution of the bridgehead carbon atoms C‐6 and C‐12 in the indenofluorene unit, prior to indenofluorene ring formation, reduces the probability of keto formation. Due to the intrinsic chemical purity of the arylated derivative, identification of a long‐delayed spectral feature, other than the known keto band, is possible in the case of thin films. Controlled doping experiments on the arylated derivative with trace amounts of an indenofluorene‐monoketone provide quantitative information on the rates of two major photophysical processes, namely, singlet photoluminescence emission and singlet photoluminescence quenching. These results allow the determination of the minimum keto concentration that can affect the intrinsic photophysical properties of this polymer. The data suggest that photoluminescence quenching operates in the doped films according to the Stern–Volmer formalism.
A Colloidal Au Monolayer Modulates the Conformation and Orientation of a Protein at the Electrode/Solution Interface
Authors: Jiang Xiue , Zhang Lei , Jiang Junguang , Qu Xiaohu , Wang Erkang , Dong Shaojun
Published: August 2005

The orientation and conformation of adsorbed cytochrome c (cyt c) at the interface between an electrode modified with colloidal Au and a solution were studied by electrochemical, spectroscopic, and spectroelectrochemical techniques. The results indicate that the colloidal Au monolayer formed via preformation of an organic self‐assembled monolayer (SAM) can increase the electronic coupling between the SAM and cyt c in the same manner as bifunctional molecular bridges, one functional group of which is bound to the electrode surface while the other interacts with the protein surface. The approach of cyt c to the modified electrode/solution interface can be assisted by strong interactions of the intrinsic charge of colloidal particles with cyt c, while the heme pocket remains almost unchanged due to the screening effect of the negatively charged field created by the intrinsic charge. The conformational changes of cyt c induced by its adsorption at a bare glassy carbon electrode/solution interface and the effect of the electric field on the ligation state of the heme can be avoided at the colloidal‐Au‐modified electrode/solution interface. Finally, a possible model for the adsorption orientation of cyt c at the colloidal‐Au‐modified electrode/solution interface is proposed.
A Theoretical Description of Elastic Pillar Substrates in Biophysical Experiments
Authors: Mohrdieck Camilla , Wanner Alexander , Roos Wouter , Roth Alexander , Sackmann Erich , Spatz Joachim P. , Arzt Eduard
Published: August 2005

Arrays of elastic pillars are used in biophysical experiments as sensors for traction forces. The evaluation of the forces can be complicated if they are coupled to the pillar displacements over large distances. This is the case if many of the pillars are interconnected by elastic linkages as, for example, in fiber networks that are grown on top of pillars. To calculate the traction forces in such a network, we developed a set of nonlinear inhomogeneous equations relating the forces in the linking elements to the resulting pillar deflections. We chose a homogeneous, activated two‐dimensional network of cytoskeletal actin filaments to illustrate that a pillar substrate is generally not a force sensor but a force‐gradient sensor. In homogeneous networks the forces acting along the filaments can be approximated by analyzing only pillar deflections in the edge zones of the substrate and by integration over the corresponding force gradients.
Kinetics of the Initial Steps of G Protein‐Coupled Receptor‐Mediated Cellular Signaling Revealed by Single‐Molecule Imaging
Authors: Lill Yoriko , Martinez Karen L. , Lill Markus A. , Meyer Bruno H. , Vogel Horst , Hecht Bert
Published: August 2005

We report on an in vivo single‐molecule study of the signaling kinetics of G protein‐coupled receptors (GPCR) performed using the neurokinin 1 receptor (NK1R) as a representative member. The NK1R signaling cascade is triggered by the specific binding of a fluorescently labeled agonist, substance P (SP). The diffusion of single receptor–ligand complexes in plasma membrane of living HEK 293 cells is imaged using fast single‐molecule wide‐field fluorescence microscopy at 100 ms time resolution. Diffusion trajectories are obtained which show intra‐ and intertrace heterogeneity in the diffusion mode. To investigate universal patterns in the diffusion trajectories we take the ligand‐binding event as the common starting point. This synchronization allows us to observe changes in the character of the ligand–receptor‐complex diffusion. Specifically, we find that the diffusion of ligand–receptor complexes is slowed down significantly and becomes more constrained as a function of time during the first 1000 ms. The decelerated and more constrained diffusion is attributed to an increasing interaction of the GPCR with cellular structures after the ligand–receptor complex is formed.
DNA labeling in living cells
Authors: Martin Robert M. , Leonhardt Heinrich , Cardoso M. Cristina
Published: August 2005

Background

Live cell fluorescence microscopy experiments often require visualization of the nucleus and the chromatin to determine the nuclear morphology or the localization of nuclear compartments.

Methods

We compared five different DNA dyes, TOPRO‐3, TOTO‐3, propidium iodide, Hoechst 33258, and DRAQ5, to test their usefulness in live cell experiments with continuous imaging and photobleaching in widefield epifluorescence and confocal laser scanning microscopy. In addition, we compared the DNA stainings with fluorescent histones as an independent fluorescent label to mark chromatin.

Results

From the dyes tested, only Hoechst and DRAQ5 could be used to stain DNA in living cells. However, DRAQ5 had several advantages, namely low photobleaching, labeling of the chromatin compartments comparable to that of H2B‐GFP fusion proteins, and deep red excitation/emission compatible with available genetically encoded fluorescent proteins such as C/G/YFP or mRFP.

Conclusions

The DNA dye DRAQ5 is well suited for chromatin visualization in living cells and can easily be combined with other fluorophores with blue to orange emission. © 2005 Wiley‐Liss, Inc.