bluuebunny/crossref_metadata_2025 huggingface dataset:
Band Analysis of Temperature-Dependent Near-Infrared Spectra of Oleic Acid in the Pure Liquid State by the Analytic Geometric Approach
Authors: Koashi Katsue , Iwahashi Makio , Ozaki Yukihiro
Published: April 2004

The applicability of the band-stripping and complementary matching method has been demonstrated by the analysis of temperature-dependent near-infrared (NIR) absorption spectra in the 7500–6500 cm−1 region of oleic acid ( cis-9-octadecenoic acid) in the pure liquid state. This method is based on first derivative–second derivative pair (D1–D2) plots and a new concept called the complementary band, cBD i, created by subtracting all the rest of the bands, exclusive of the ith estimated band, eBD i, from an experimental spectrum. The degree of coincidence of both band shapes provides a suitable measure for the quality of fit for each individual component band. It has been confirmed from the present analysis of the NIR spectra of oleic acid measured over a temperature range of 16–79 °C that the change of the peak intensity of the component band at around 6915 cm−1 due to the first overtone of an O–H stretching vibration of the monomer has two transition points around 35 and 55 °C. Moreover, the present study has provided new insight into the analysis of temperature-dependent spectral variations of oleic acid. Among the three temperature ranges, 16–35 °C, 35–55 °C, and 55–79 °C, in the first range the band near 6915 cm−1 shows a slight increase and in the second range it has a linear intensity change with a slope of 0.002 a.u./°C. In the third range, a rapid increase of the peak intensity is observed. This band exists even at 15 °C (just below the melting point) and shows a shift from 6910 to 6915 cm−1 and a band narrowing from 85 to 80 cm−1 (full width at half-height) over a temperature range of 16 to 79 °C. Furthermore, it has been found that there are two broad bands at around 6835 and 6778 cm−1.
Submicrometer Spatial Resolution of Metal-Enhanced Fluorescence
Authors: Pugh Vincent J. , Szmacinski Henryk , Moore Wayne E. , Geddes Chris D. , Lakowicz Joseph R.
Published: April 2004

Enhanced fluorescence emission intensity from fluorescein was observed on glass slides covered with thin films of silver nanoparticles using a confocal laser-scanning microscope. The silver nanoparticle film increased the emission intensity of fluorescein by an average of at least three-fold in the area studied. Statistics are given on the enhancement of individual areas of the silver particle film with a resolution of approximately 210 nm. A histogram of intensity values indicates that the enhancement appears to occur without distinct subpopulations, with the exception that very high intensity subpopulations may occur but could not be resolved. Spatial features with dimensions near or smaller than the resolution limit of the confocal microscope, on the silver nanoparticle slide that enhanced the emission of fluorescein, were found using autocorrelation functions. These spatial features are of the same size as those found from the emission of slides containing silver nanoparticles only. These spatial features do not appear in control slides containing fluorescein without any silver nanoparticles. No long-range spatial ordering of the fluorescence enhancement on chemcially deposited silver nanoparticle slides was detected.
Laser Ablation Inductively Coupled Plasma Mass Spectrometry Measurement of Isotope Ratios in Depleted Uranium Contaminated Soils
Authors: Seltzer Michael D.
Published: April 2004

Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma.
Spectra and Concentration Profiles Throughout the Reaction of Curing Epoxy Resins from Near-Infrared Spectroscopy and Multivariate Curve Resolution Methods
Authors: Larrechi M. S. , Rius F. X.
Published: April 2004

When applied to near-infrared (NIR) data, multivariate curve resolution methods, in particular alternating least squares (ALS), make it possible to calculate the concentration profiles and the spectra of all species involved in the reaction of curing epoxy resins. In this paper, the model reaction between phenyl glicidyl ether and aniline (2:1) was studied at 95 °C. A NIR spectrum was recorded every five minutes throughout the eight-hour reaction process. The data display rank deficiency. This problem was overcome by supplying additional information to the system in the form of known spectra of some reactants. The recovered spectra and concentration profiles satisfactorily reproduced the experimental data. In this way, 99.99% of the variance associated with the experimental matrix was reproduced. A value of 0.87% was obtained for lack of fit while the similarity coefficient r between the spectra recovered and the spectra corresponding to the three pure species involved in the reaction were PGE ( r = 0.994), aniline ( r = 0.994), and tertiary amine ( r = 0.999). The maximum and minimum limits associated with the ALS solutions were calculated, which made it possible to limit to a considerable extent the ambiguity that is characteristic of these curve resolution methods.
Effects of CaCl2 and MgCl2 on Fourier Transform Infrared Spectra of Lung Cancer Cells
Authors: Sulé-Suso J. , Forster A. , Zholobenko V. , Stone N. , Haj A. El
Published: April 2004

The cations Ca2+ and Mg2+ are two important factors in the growth and maintenance of living cells. The addition of Ca2+ to living cells can cause a change in the three-dimensional (3D) structure of calcium binding proteins. Therefore, we decided to study whether the addition of CaCl2 and MgCl2 to three in vitro growing lung cancer cell lines could cause changes that could be measured by Fourier Transform Infrared Spectroscopy. The addition of CaCl2 or MgCl2 to lung cancer cells caused an increase in absorbance of the trough at 1410 cm−1. This translated into an inversion of the 1410/1395 cm−1 ratio following the addition of CaCl2 or MgCl2 for all three lung cancer cell lines. Also, the amide I peak shifted from around 1631 cm−1 to lower wavenumbers when CaCl2 or MgCl2 was added to cancer cells. Furthermore, the addition of these two substances caused a shift of the peak between 3290 and 3395 cm−1. Finally, while the addition of CaCl2 to lung cancer cells was associated with an increased cell death, this was not the case following the addition of MgCl2. This would confirm that the changes seen in the spectra of all three cell lines are due to metabolic and ionic shifts rather than cell death.
Integrated Gas Analyzer for Complete Monitoring of Turbine Engine Test Cells
Authors: Markham James R. , Bush Patrick M. , Bonzani Peter J. , Scire James J. , Zaccardi Vincent A. , Jalbert Paul A. , Bryant M. Denise , Gardner Donald G.
Published: April 2004

Fourier transform infrared (FT-IR) spectroscopy is proving to be reliable and economical for the quantification of many gas-phase species during testing and development of gas turbine engines in ground-based facilities such as sea-level test cells and altitude test cells. FT-IR measurement applications include engine-generated exhaust gases, facility air provided as input to engines, and ambient air in and around test cells. Potentially, the traditionally used assembly of many gas-specific single gas analyzers will be eliminated. However, the quest for a single instrument capable of complete gas-phase monitoring at turbine engine test cells has previously suffered since the FT-IR method cannot measure infrared-inactive oxygen molecules, a key operational gas to both air-breathing propulsion systems and test cell personnel. To further the quest, the FT-IR sensor used for the measurements presented in this article was modified by integration of a miniature, solid-state electrochemical oxygen sensor. Embedded in the FT-IR unit at a location near the long-effective-optical-path-length gas sampling cell, the amperometric oxygen sensor provides simultaneous, complementary information to the wealth of spectroscopic data provided by the FT-IR method.
Fluorescence Anisotropy in the Frequency Domain by an Optical Microscope
Authors: Collini Maddalena , D'Alfonso Laura , Baldini Giancarlo , Oldani Amanda , Cellai Luciano , Giordano Cesare , Barone Flavia , Mazzei Filomena , Chirico Giuseppe
Published: April 2004

Fluorescence anisotropy decay spectroscopy is a suitable tool for investigating the size and the shape of biological molecules. We coupled this technique to an optical microscope in order to reduce the excitation volume and to allow its application to spatially inhomogeneous samples. Phase modulated measurements of the fluorescence anisotropy decay were performed by feeding an intensity modulated linearly polarized laser beam to the epifluorescence port of a microscope. Here we report the test of the dynamic response of the microscope by comparing the lifetime and fluorescence polarization anisotropy decays obtained in cuvettes in a standard phase modulation fluorometer and on tiny drops on the microscope stage. We show that once a correction factor for the objective depolarization is introduced in the best-fit functions for the data analysis of the decays, the results obtained on the two setups are comparable. Some applications are reported here on long DNA tracts as well on short DNA fragments containing structural anomalies.
Binding of Aromatic Isocyanides on Gold Nanoparticle Surfaces Investigated by Surface-Enhanced Raman Scattering
Authors: Joo Sang-Woo , Kim Wan-Joong , Yun Wan Soo , Hwang Sungu , Choi Insung S.
Published: April 2004

The adsorption structure and binding of phenyl isocyanide (PNC), 2,6-dimethyl phenyl isocyanide (DMPNC), and benzyl isocyanide (BZI) on gold nanoparticle surfaces have been studied by means of surface-enhanced Raman scattering (SERS). PNC, DMPNC, and BZI have been found to adsorb on gold assuming a standing geometry with respect to the surfaces. The presence of the v(CH) band in the SERS spectra denotes a vertical orientation of the phenyl ring of PNC, DMPNC, and BZI on Au. The lack of a substantial red shift and significant band broadening of the ring breathing modes implied that a direct ring π orbital interaction with metal substrates should be quite low. For PNC, the band ascribed to the C–NC stretching vibration was found to almost disappear after adsorption on Au. On the other hand, the C–NC band remained quite strong for DMPNC after adsorption. This result suggests a rather bent angle of C–N≡C: for the nitrogen atom of the NC binding group on the surfaces, whereas a linear angle of C–N≡C: should be more favorable on gold surfaces due to an intramolecular steric hindrance of its two methyl groups. SERS of BZI on gold nanopaticles also supports a bent angle of: C≡N–CH2 for its nitrogen atom, suggesting a preference of sp3 (or sp2) hybridization for the nitrogen atom.
Near-Field Infrared Imaging and Spectroscopy of a Thin Film Polystyrene/Poly(Ethyl Acrylate) Blend
Authors: Michaels Chris A. , Gu Xiaohong , Chase D. Bruce , Stranick Stephan J.
Published: April 2004

The application of broadband, near-field infrared microscopy to the characterization of the mesoscale structure of a thin film polymer blend is described. Key features of this instrument, which couples the nanoscale spatial resolution of scanning probe microscopy with the chemical specificity of vibrational spectroscopy, include broad tunability and bandwidth, parallel spectral detection for high image acquisition rates, and infrared-transparent aperture probes. Near-field spectral transmission images of a thin film of polystyrene/poly(ethyl acrylate) acquired in the C–H stretching region are reported. An assessment of the relative importance of transmission image contrast mechanisms is a significant aim of this work. Analysis of the near-field infrared spectra indicates that the image contrast in the C–H stretching region is largely due to near-field coupling and/or scattering effects. Identification and differentiation of the operative contrast mechanisms on the basis of their relative dependence on wavelength is discussed. Analysis of the contrast attributed to absorption is consistent with the chemical morphology of this sample derived from previous chemical modification/atomic force microscopy studies.
Infrared Absorption Enhancement of C60 by Overlaying Thin Silver Island Films
Authors: Wadayama T. , Aoshima K. , Kawano S. , Hatta A.
Published: April 2004

Normal-incidence infrared absorption has been observed for silver overlaid C60 thin films formed on surface-oxidized Si(111) substrates as a function of the silver or C60 film thickness. The absorption spectra exhibit bands at 1429 and 1180 cm−1 due, respectively, to the infrared active T1u (4) and T1u (3) modes of C60 in multi-layers. Additionally, two bands appear at 1442 and 1370 cm−1. The former band is caused by activation of the infrared inactive (Raman active) Ag (2) mode via electron transfer from the silver to adsorbed C60, and the latter is assigned to the T1u (4) mode red-shifted by the charge transfer. These bands are all enhanced in intensity dependent either upon the silver or C60 thickness, i.e., the largest absorption enhancement is obtained for 25-monolayers-thick silver and 12-nm-thick C60. Under atomic force microprobe inspection, the average size and height of the islands in the overlaid 25-monolayers-thick silver change with underlying C60 film thickness. The influence of the C60 film structure upon the silver film and in turn the absorption intensity is strongly suggested.
Characterization of an Optoelectronic Polymer, Poly(2-Phenoxy p-Phenylene Vinylene), and its Precursor Polymer by Dynamic Infrared Spectroscopy
Authors: Wilking James N. , Manning Christopher J. , Arbuckle-Keil Georgia A.
Published: April 2004

Numerous applications of dynamic infrared spectroscopy to study a variety of polymer systems have been described in the literature. Typically, dynamic spectral changes are used to determine the molecular and submolecular reorientations that give rise to a material's observable mechanical properties. In the present study, the normal modes are characterized by their time-dependent response to an applied perturbation as an aid to assignment of the observed vibrational bands. Characterization of a newly synthesized optoelectronic polymer, poly(2-phenoxy p-phenylene vinylene), and its precursor polymer, is described. Vibrational modes along the backbone and side chain are expected to exhibit significantly different responses to mechanical perturbation due to delayed phase response of the phenoxy substituent. In-phase spectra, quadrature spectra, and two-dimensional infrared correlation maps are included in this characterization. This study has demonstrated that dynamic infrared spectroscopy can be used to distinguish backbone phenylene ring stretches from ring stretches associated with the phenoxy substituent. Density functional theory calculations are applied to confirm infrared spectral assignments. The mechanical properties are briefly discussed in light of the dynamic response.
Analysis of Latent Fingerprint Deposits by Infrared Microspectroscopy
Authors: Williams Diane K. , Schwartz Rebecca L. , Bartick Edward G.
Published: April 2004

We report the use of infrared (IR) microspectroscopy for the analysis of fingerprint residues. The advantage of using an IR microscope lies in the ability to visualize and obtain spectra of individual particles and droplets that make up fingerprint ridge deposits at a spatial resolution of approximately 10 μm. Our initial results suggest that infrared microspectroscopy in reflection–absorption mode provides reproducible spectral analysis of fingerprint residue. Since infrared microspectroscopy is nondestructive to the sample, we will be able to study the changes in fingerprint ridge deposits as a function of time. The method holds promise for probing the difference between latent fingerprints of adults and children.
Structural Changes in the Cells of Some Bacteria during Population Growth: A Fourier Transform Infrared—Attenuated Total Reflectance Study
Authors: Ede Sarah M. , Hafner Louise M. , Fredericks Peter M.
Published: April 2004

Structural changes occurring in the cells of several bacteria during their growth curves have been investigated by Fourier transform infrared (FT-IR) spectroscopy using the sampling technique of attenuated total reflectance (ATR). Spectra reflect all of the components of the cells, including the cell walls, cell membranes, internal structures, and the cytoplasm. The bacteria studied were Bacillus stearothermophilus, Halobacterium salinarium, Halococcus morrhuae, and Acetobacter aceti. All species showed significant spectral changes during their growth curves, indicating structural changes in the cells during increases in cell numbers. The major change for B. stearothermophilus was in the lipid content, which was at a maximum during the exponential phase of the growth curve. For the halophiles H. salinarium and H. morrhuae, the major change was that the concentration of sulfate ion in the cells varied during the growth curve and was at a maximum during the mid-part of the exponential phase of the growth curve. A. aceti cells showed increasing polysaccharide content during the growth curve as well as maximum lipid content during the exponential phase of growth.
Vibrational Analysis of Structure Activity Relationships (SAR) in Molecular Binding
Authors: Pivonka Don
Published: April 2004

A novel vibrational spectroscopic approach has been developed to better understand the structure activity relationship (SAR) component of the drug discovery effort. First, vibrational spectroscopy has been developed as a tool for the identification of molecular subcomponents within a compound series, which play an active role in binding kinetics. Second, vibrational spectroscopy has exhibited utility in uncovering electronic trends within both pendant functional groups and within the molecular backbone scaffold, which foster the binding process. In this study, three series of compounds (isoflavone, coumarin, and benzoxazole) within a human estrogen receptor (ER-β) study were used to explore the feasibility of the technique. In each series, infrared and Raman band shifts, which correlated with ER-β binding activity, were identified. Data indicated binding activity to be strongly influenced by electron density in the pi-bonding system of the backbone scaffold for each series. The ability to relate the physical/electronic state of a molecular subcomponent to activity has far-reaching implications in the identification and optimization of binding activity. The preliminary success of this project opens the door to a much broader investigation of the technique using a host of spectroscopic methodologies.
Postoperative Plasma Metabolic Consequences of an Osseous Substitute Implantation: Analysis by Fourier Transform Infrared Spectroscopy
Authors: Lorin Chrystelle , Melin Anne-Marie , Chenu Jean-Patrick , Perromat Annie , Déléris Gérard
Published: April 2004

In this study, we have investigated the postoperative plasma consequences of coral implantation into femoral condyle of rabbits. Analyses were performed using Fourier transform infrared (FT-IR) spectroscopy, a sensitive and nondestructive method, to evaluate plasma modifications one day, one week, one month, and three months after surgery. This technique showed that both surgery and implantation induced important changes of lipidic compounds one day after surgery, with a body lipolysis. Major modifications appeared one week after surgery, with a decrease of protein and saccharide contents, and an increase of amino acids accompanied by a noticeable inflammatory process. These last changes were revealed by a hierarchical classification in the 1430–1295 and 1137–1092 cm−1 spectral regions, leading to two well-separated groups, before and one week after surgery. After a delayed time of three months and despite a substantial recovery for biomolecules such as proteins and fatty acids, some alterations are always observed, such as for amino acids, triglycerides, and glycerol. Moreover, molecules implicated in the inflammatory process had not reached their initial level.
Uncertainties in Depth Determination and Comparison of Multivariate with Univariate Analysis in Confocal Raman Studies of a Laminated Polymer and Skin
Authors: Xiao Chunhong , Flach Carol R. , Marcott Curtis , Mendelsohn Richard
Published: April 2004

Confocal Raman microscopy data are reported for a laminated polymer (Paramount) and for pigskin. The nature of the laminated structure of the polymer provides a useful test for evaluation of thickness distortions in confocal measurements in soft samples, which are found to be quite significant. The spatial variation in line profiles generated from univariate analyses with scores derived from factor loadings are consistent for both samples and provide distinct diagnostic markers for stratum corneum and epidermis regions of skin. Univariate analysis of the C–C stretching region of skin reveals a spatial dependence of chain conformational order. In addition, variations in keratin-containing areas of the stratum corneum are readily identified from area maps of the S–S stretching vibrations. These data indicate that confocal Raman imaging studies of molecular structure changes in particular regions of skin during pathological processes will prove quite valuable in dermatology.
Confocal Raman Microscopy of Morphological Changes in Poly(Ethylene Terephthalate) Film Induced by Supercritical CO2
Authors: Fleming Oliver S. , Kazarian Sergei G.
Published: April 2004

Poly(ethylene terephthalate) (PET) film was exposed to supercritical (sc) CO2 and confocal Raman microscopy was used to investigate the morphological changes induced. The study evaluates the use of oil and dry objectives in confocal mode to obtain depth profiles of PET film. These results were compared with the data obtained by mapping of the film cross-section. A significant gradient of degree of crystallinity normal to the surface of PET film down to 60 μm has been observed. The gradient of the degree of morphological changes are functions of exposure time and pressure.
Rapid Quantification of Carotenoids and Fat in Atlantic Salmon (Salmo Salar L.) by Raman Spectroscopy and Chemometrics
Authors: Wold Jens Petter , Marquardt Brian J. , Dable Brian K. , Robb Dave , Hatlen Bjarne
Published: April 2004

Raman spectroscopy (785 nm excitation) was used to determine the overall carotenoid (astaxanthin and cantaxanthin) and fat content in 49 samples of ground muscle tissue from farmed Atlantic salmon ( Salmo salar L.). Chemically determined contents ranged from 1.0 to 6.8 mg/kg carotenoids and 36 to 205 g/kg fat. In addition to the raw Raman spectra, three types of spectral preprocessing were evaluated: the first derivative, subtraction of the fitted fourth-order polynomial (POLY), and the intensity normalized versions of POLY (POLY-SNV). Further, variable selection based on significance testing by use of jack-knifing was performed on each spectral data set. Partial least-squares regression resulted in a root mean square error of prediction of 0.33 mg/kg ( R = 0.97) for carotenoids for the variable selected versions of all the preprocessed spectral data sets. The fat content was best estimated by the variable selected POLY-SNV, resulting in a root mean square error of prediction of 15.5 g/kg ( R = 0.95). Both preprocessing and variable selection improved the regression models significantly. The results demonstrate that Raman spectroscopy is a suitable method for simultaneous, rapid, and nondestructive quantification of both pigments and fat in ground salmon muscle tissue.
Analysis of Phthalate Ester Content in Poly(Vinyl Chloride) Plastics by Means of Fourier Transform Raman Spectroscopy
Authors: Nørbygaard T. , Berg R. W.
Published: April 2004

Fourier transform (FT) Raman spectroscopy is applied to a range of phthalate ester plasticizers in pure form as well as in poly(vinyl chloride) (PVC) samples. It is found that phthalate esters as a group can be identified by a set of six characteristic Raman bands. FT-Raman spectra of 22 phthalate esters are given. It is demonstrated that the presence of phthalate esters in PVC products is readily detectable by FT-Raman spectroscopy. By use of proper reference samples quantitative determination of the phthalate ester content becomes possible as well.
In situ Analysis of Metal Melts in Metallurgic Vacuum Devices by Laser-Induced Breakdown Spectroscopy
Authors: Gruber J. , Heitz J. , Arnold N. , Bäuerle D. , Ramaseder N. , Meyer W. , Hochörtler J. , Koch F.
Published: April 2004

We report on rapid in situ analysis of liquid metal melts under reduced ambient pressure by laser-induced breakdown spectroscopy (LIBS) using a transportable system. LIBS denotes a method in which characteristic optical emission line intensities of excited species in laser-generated plasma plumes are used for a quantitative chemical analysis of target materials. It is a fast, noncontact method that can be carried out under various atmospheric conditions, allowing large working distances between the sample under investigation and the detection system. For these reasons, LIBS is applicable in particular for process control in metallurgy under reduced ambient pressure. This was demonstrated for two types of vacuum devices under production conditions at a steel mill. The results of these experiments, including calibration curves for Cr, Ni, and Mg in liquid steel, are presented. The influence of variations in the ambient pressure on the results of the LIBS analysis is discussed within the frame of a generalized shock-wave model for the expansion of the laser-induced plasma plume.
Hidden Isosbestic Point(s) in Ultraviolet Spectra
Authors: Pouët M.-F. , Baures E. , Vaillant S. , Thomas O.
Published: April 2004

The existence of isosbestic point(s) in a set of UV-visible spectra is rarely exploited for quantitative or qualitative information despite its interest. Indeed, the presence of isosbestic points means a quality and quantity conservation in the global composition of samples with a given relation between the concentration of absorbing compounds or mixtures of compounds. However, in some cases, for example, when a dilution occurs, no isosbestic point appears. This work shows that a simple operation, called normalization, can reveal the existence of hidden isosbestic point(s) (IP*). This paper first summarizes the required conditions for the presence of isosbestic points. Second, it demonstrates the significance of IP* revealed by normalization. An example of the exploitation of direct or hidden isosbestic points in the environmental field illustrates the interest in and application of the technique.
Multiple Forms of Long-Term Potentiation and Long-Term Depression Converge on a Single Interneuron in the Leech CNS
Authors: Burrell Brian D. , Sahley Christie L.
Published: April 2004

Long-term potentiation (LTP) of synaptic transmission was observed in two types of synapses that converge on the same postsynaptic neuron in the leech CNS. These synapses were made by identifiable sensory neurons, the mechanosensory touch (T-) and pressure (P-) cells, onto the S-cell, an interneuron critical for certain forms of learning. Changes in both the T-S and P-S synapses appear to be activity dependent because LTP was restricted to inputs that had undergone tetanization; however, properties of synaptic plasticity at the T-S and P-S connections differ considerably. At the P-S synapse, LTP was induced in the tetanized synapse but not in the nontetanized synapse tested in parallel. P-S LTP was blocked by the NMDA receptor antagonistdl-2-amino-5-phosphono-valeric acid (AP-5) or by lowering the extracellular concentration of glycine, an NMDA receptor (NMDAR) co-agonist. P-S LTP was strongly affected by the initial amplitude of the synaptic potential at the time LTP was induced. Smaller amplitude synapses (<3.5 mV) underwent robust potentiation, whereas the less common, larger amplitude synapse (>3.5 mV) depressed after tetanization. At the T-S synapse, tetanization simultaneously induced homosynaptic LTP in the tetanized input and heterosynaptic long-term depression (LTD) in the input made by a nontetanized T-cell onto the same S-cell. Interestingly, AP-5 failed to block homosynaptic LTP at the T-S synapse but did prevent heterosynaptic LTD. T-S LTP was not affected by the initial EPSP amplitude. Thus, leech neurons exhibit synaptic plasticity with properties similar to LTP and LTD found in the vertebrate nervous system.
Age-Dependent Neurodegeneration and Alzheimer-Amyloid Plaque Formation in TransgenicDrosophila
Authors: Greeve Isabell , Kretzschmar Doris , Tschäpe Jakob-Andreas , Beyn Anika , Brellinger Claire , Schweizer Michaela , Nitsch Roger M. , Reifegerste Rita
Published: April 2004

β-Amyloid peptides that are cleaved from the amyloid precursor protein (APP) play a critical role in Alzheimer's disease (AD) pathophysiology. Here, we show that inDrosophila, the targeted expression of the key genes of AD, APP, theβ-site APP-cleaving enzyme BACE, and the presenilins led to the generation of β-amyloid plaques and age-dependent neurodegeneration as well as to semilethality, a shortened life span, and defects in wing vein development. Genetic manipulations or pharmacological treatments with secretase inhibitors influenced the activity of the APP-processing proteases and modulated the severity of the phenotypes. This invertebrate model of amyloid plaque pathology demonstrates Aβ-induced neurodegeneration as a basic biological principle and may allow additional genetic analyses of the underlying molecular pathways.
Acid-Sensing Ion Channel-2 Is Not Necessary for Sour Taste in Mice
Authors: Richter Trevor A. , Dvoryanchikov Gennady A. , Roper Stephen D. , Chaudhari Nirupa
Published: April 2004

The acid-sensitive cation channel acid-sensing ion channel-2 (ASIC2) is widely believed to be a receptor for acid (sour) taste in mammals on the basis of its physiological properties and expression in rat taste bud cells. Using reverse transcriptase-PCR, we detected expression of ASIC1 and ASIC3, but not ASIC4, in mouse and rat taste buds and nonsensory lingual epithelium. Surprisingly, we did not detect mRNA for ASIC2 in mouse taste buds, although we readily observed its expression in rat taste buds. Furthermore, in Ca2+imaging experiments, ASIC2 knock-out mice exhibited normal physiological responses (increases in intracellular Ca2+concentrations) to acid taste stimuli. Our results indicate that ASIC2 is not required for acid taste in mice, and that if a universal mammalian acid taste transduction mechanism exists, it likely uses other acid-sensitive receptors or ion channels.
Mice Lacking Sodium Channel β1 Subunits Display Defects in Neuronal Excitability, Sodium Channel Expression, and Nodal Architecture
Authors: Chen Chunling , Westenbroek Ruth E. , Xu Xiaorong , Edwards Chris A. , Sorenson Dorothy R. , Chen Yuan , McEwen Dyke P. , O'Malley Heather A. , Bharucha Vandana , Meadows Laurence S. , Knudsen Gabriel A. , Vilaythong Alex , Noebels Jeffrey L. , Saunders Thomas L. , Scheuer Todd , Shrager Peter , Catterall William A. , Isom Lori L.
Published: April 2004

Sodium channel β1 subunits modulate α subunit gating and cell surface expression and participate in cell adhesive interactionsin vitro. β1(-/-) mice appear ataxic and display spontaneous generalized seizures. In the optic nerve, the fastest components of the compound action potential are slowed and the number of mature nodes of Ranvier is reduced, but Nav1.6, contactin, caspr 1, and Kv1 channels are all localized normally at nodes. At the ultrastructural level, the paranodal septate-like junctions immediately adjacent to the node are missing in a subset of axons, suggesting that β1 may participate in axo-glial communication at the periphery of the nodal gap. Sodium currents in dissociated hippocampal neurons are normal, but Nav1.1 expression is reduced and Nav1.3 expression is increased in a subset of pyramidal neurons in the CA2/CA3 region, suggesting a basis for the epileptic phenotype. Our results show that β1 subunits play important roles in the regulation of sodium channel density and localization, are involved in axo-glial communication at nodes of Ranvier, and are required for normal action potential conduction and control of excitabilityin vivo.
Mutations inCaenorhabditis elegansCytoplasmic Dynein Components Reveal Specificity of Neuronal Retrograde Cargo
Authors: Koushika Sandhya P. , Schaefer Anneliese M. , Vincent Rose , Willis John H. , Bowerman Bruce , Nonet Michael L.
Published: April 2004

We describeCaenorhabditis elegansdynein complex mutants, which misaccumulate synaptic proteins at the ends of neuronal processes. Ultrastructural analysis revealed irregularly sized vesicles that likely represent accumulation of cargo. We propose that synaptobrevin, synaptotagmin, and UNC-104 are specific cargoes of the dynein complex. Many cargoes link to dynein via interactions between dynactin and vesicle-associated spectrin. However, loss of spectrin results in only mild and occasional defects in synaptobrevin localization. Thus, the dynein-dynactin complex shows neuronal cargo selectivity without spectrin being a critical component of cargo binding. We observed parallels to progressive motor neuron disease symptoms in these animals. With age, neuronal misaccumulations increase in size and frequency; locomotion becomes progressively slower; and life span is shortened. These mutants provide a model to assess whether defects in transport of specific cargo mediate neuronal dysfunction.
Genetic Analysis of SolubleN-Ethylmaleimide-Sensitive Factor Attachment Protein Function inDrosophilaReveals Positive and Negative Secretory Roles
Authors: Babcock Michael , Macleod Greg T. , Leither Jennifer , Pallanck Leo
Published: April 2004

TheN-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment protein (SNAP) are cytosolic factors that promote vesicle fusion with a target membrane in both the constitutive and regulated secretory pathways. NSF and SNAP are thought to function by catalyzing the disassembly of a SNAP receptor (SNARE) complex consisting of membrane proteins of the secretory vesicle and target membrane. Although studies of NSF function have provided strong support for this model, the precise biochemical role of SNAP remains controversial. To further explore the function of SNAP, we have used mutational and transgenic approaches inDrosophilato investigate the effect of altered SNAP dosage on neurotransmitter release and SNARE complex metabolism. Our results indicate that reduced SNAP activity results in diminished neurotransmitter release and accumulation of a neural SNARE complex. Increased SNAP dosage results in defective synapse formation and a variety of tissue morphological defects without detectably altering the abundance of neural SNARE complexes. The SNAP overexpression phenotypes are enhanced by mutations in other secretory components and are at least partially overcome by co-overexpression of NSF, suggesting that these phenotypes derive from a specific perturbation of the secretory pathway. Our results indicate that SNAP promotes neurotransmitter release and SNARE complex disassembly but inhibits secretion when present at high abundance relative to NSF.
Selbstnachführendes Laserinterferometer für die Koordinatenmesstechnik (Tracking Laser Interferometer for Coordinate Metrology)
Authors: Härtig Frank , Keck Christian , Kniel Karin , Schwenke Heinrich , Wäldele Franz , Wendt Klaus
Published: April 2004

Die Genauigkeit von Koordinatenmessgeräten (KMG) kann durch die Integration eines selbstnachführenden Laserinterferometers deutlich verbessert werden. Das in der Physikalisch-Technischen Bundesanstalt (PTB) entwickelte Verfahren verknüpft die Koordinaten jedes gemessenen Punktes des KMG mit einer hochgenauen interferometrischen Längeninformation. Die zentrale Komponente hierbei ist das ebenfalls in der PTB entwickelte selbstnachführende Laserinterferometer. Sein konstruktiver Aufbau ermöglicht hochgenaue Abstandsmessungen im Raum. Ergebnisse aus Simulationen und Messungen verifizieren das neue Verfahren.
Mehrkanalige Signalschätzung für die technische Diagnose (Multi-channel Signal Estimation for Machine Diagnosis)
Authors: Knaak Mirko , Filbert Dieter
Published: April 2004

Die akustische Maschinendiagnose hat die Aufgabe, aus dem möglicherweise verrauschten und durch andere Signale gestörten Schallsignal einer Maschine auf deren Fehlerzustand zu schließen. Da dieses Mustererkennungsproblem bereits bei ungestörten Signalen schwierig ist, wird vorgeschlagen, die Störungen mit einer mehrkanaligen Signalschätzung zu eliminieren. Der vorgestellte Algorithmus beruht auf den Methoden der ICA (Independent Component Analysis), integriert vorhandene, jedoch ungenaue geometrische Informationen und erzielt somit sehr gute Schätzraten bei hoher Robustheit. Er ist nicht wie die derzeitigen Algorithmen der akustischen blinden Quellentrennung auf zwei Signale begrenzt und erzielt somit sehr gute Schätzraten bei höherer Robustheit als adaptive Beamformer.
Annealing studies of high Ge composition Si/SiGe multilayers
Authors: Meduňa Mojmír , Novák Jiří , Bauer Günther , Holý Václav , Falub Claudiu Valentin , Tsujino Soichiro , Müller Elisabeth , Grützmacher Detlev , Campidelli Yves , Kermarrec Olivier , Bensahel Daniel
Published: April 2004

For the design flexibility of SiGe based quantum cascade lasers high Ge composition Si/SiGe (x = 80%) superlattices are important. We present an X-ray small angle scattering and high-resolution X-ray diffraction study on strain compensated Si/Si1–

x
Gex multiple quantum well structures with Ge compositions (x up to 80%), grown on Si0.5Ge0.5 pseudo-substrates. To test the temperature stability of such layers occurring in processing steps, in-situ annealing X-ray reflectivity measurements were performed for temperatures up to 810 °C. From the analysis of the reflectivity data, we obtain the layer thicknesses and the interface roughness of the superlattices during annealing. Using a one dimensional diffusion equation, the Ge diffusion coefficient for these conditions was obtained. Furthermore, the strain status and Ge composition in the superlattice structure and in the SiGe buffer before and after annealing were determined from the symmetrical and asymmetrical reciprocal space maps.
Polymeric structures at interfaces: An X-ray scattering study
Authors: Panagiotou Panteleimon , Bauer Estelle , Loi Simona , Titz Tobias , Maurer Edith , Müller-Buschbaum Peter
Published: April 2004

X-ray scattering based on synchrotron radiation enables the detection of polymeric structures at interfaces despite the weak contrast between adjacent polymers build-up from different monomeric units. Variable types of polymeric structures result from typical pattern directing mechanisms, such as dewetting in case of homopolymer films, phase separation in polymer blend films, micro-phase separation in diblock copolymer films and surface enrichment in statistical copolymer films. The pattern directing mechanisms introduce structures ordered perpendicular and parallel to the polymeric surface. Consequently, specular and off-specular X-ray scattering is applied as demonstrated within examples. From scattering the characteristic structures which are not accessible by means of other techniques are determined. Limitations with respect to isolated objects such as holes are discussed.
Epidemiology and Geography of Type 2 Diabetes Mellitus
Authors: Qiao Qing , Williams Desmond E. , Imperatore Giuseppina , Narayan K.M. Venkat , Tuomilehto Jaakko
Published: April 2004

The prevalence of diabetes and impaired glucose metabolism has increased dramatically and has become a serious public health problem worldwide. Age‐ and sex‐specific prevalence of diabetes, impaired glucose tolerance, and impaired fasting glycemia in different ethnic groups in different regions are presented in the chapter. The prevalence of fasting and postload hyperglycemia, the gender difference in the prevalence, the ratio of impaired glucose tolerance to diabetes, and the proportion of undiagnosed diabetes are all reported. The problems with the evolution of the diagnostic criteria for diabetes and other abnormal glucose categories are also addressed. The prevalence estimates presented in the chapter were collected mainly from studies where age‐ and sex‐specific prevalence had been estimated using the World Health Organization 1999 criteria. The secular trend in the prevalence of type 2 diabetes is discussed. The prevalence and the incidence of type 2 diabetes in children and the problem of differentiation between type 1 and type 2 diabetes are also discussed.
Lipid and Lipoprotein Metabolism
Authors: Ruotolo Giacomo , Howard Barbara V.
Published: April 2004

The three major components of the dyslipidemia associated with insulin resistance are increased fasting and postprandial triglyceride‐rich lipoproteins (TRLs), decreased high‐density lipoprotein (HDL), and increased small, dense low‐density lipoprotein (LDL) particles. The insulin resistance and compensatory hyperinsulinemia lead to overproduction of VLDL particles, an early abnormality of insulin resistance. A relative defective lipoprotein lipase (LPL)‐mediated lipolysis has also an important role in the dyslipidemia, since largely contributes to the decreased clearance of fasting and postprandial TRLs and to the decreased production of HDL particles. The resulting increased concentration of cholesteryl ester‐rich fasting and postprandial TRLs [intermediate‐density lipoprotein (IDL) and chylomicron remnants, respectively] is a central lipoprotein abnormality of insulin resistance. The increase of small, dense LDL particles, and decrease of large, buoyant HDL particles seem to be consequential events of the delayed metabolism of TRLs. The dyslipidemia associated with insulin resistance plays a major role in the development of atherosclerosis, and contributes largely to the increased cardiovascular disease risk in individuals with insulin resistance. Peroxisome proliferator‐activated receptors (PPARs) (α, γ, and δ) are ligand‐activated transcription factors belonging to the nuclear receptor family. PPARs agonists seem to improve the dyslipidemia of insulin resistance, by regulating the expression of important genes involved in the deranged lipoprotein metabolism associated with insulin resistance. New compounds with multiple PPAR‐agonist activity are currently under investigation, and could represent a possible solution to the radical treatment of the dyslipidemia of insulin resistance.
Exercise
Authors: Galbo Henrik , Richter Erik A.
Published: April 2004

If type 1 diabetic patients take too little insulin, exercise accelerates the rate at which hyperglycemia and ketosis develop. On the other hand, if the patients take too much insulin, hypoglycemia develops more rapidly, if they also exercise. However, education and home monitoring of blood glucose concentrations allow insulin‐treated diabetic patients to change amount and timing of insulin and food intake to cope with any exercise challenge. In type 2 diabetic patients the metabolic risks with exercise are less. In the postprandial state exercise always reduces glucose levels, and the decrease seems determined primarily by overall energy expenditure. In response to regularly repeated exercise, i.e. training, type 2 diabetic patients show an increase in insulin sensitivity in muscle and a reduction in HbA1clevels. In contrast, type 1 diabetic patients cannot be recommended training as a means to improve glycemic control. However, in addition to mental and social benefits both groups may achieve improvements in aerobic exercise capacity, muscle strength, arterial blood pressure, and endothelium‐dependent vasodilation by training. Furthermore, cardiovascular morbidity and mortality are lower and life expectancy increased in physically active compared with sedentary diabetic patients. The risk of getting type 2 diabetes can also be reduced by an active life style. Before increasing the level of physical activity all diabetic patients should undergo a thorough medical evaluation. In case of overt or suspected clinically silent long‐term complications the examination should include a graded exercise test with ECG and blood pressure measurement. Based on the examination an appropriate program, which accounts for individual limitations and preferences and includes, for instance, both aerobic and resistance training, can be worked out for all patients.
Education of the Diabetic PatientThis article is based in part on a chapter of the same title that was published in an earlier edition of theInternational Textbook of Diabetes Mellitus, by J.L. Day and J.‐P. Assal.
Authors: Day J.L.
Published: April 2004

This chapter provides an overview of the importance of patient education in the clinical area of those with diabetes. A historical review of its development is provided, followed by the determinants of success or failure of educational processes. These include the weak relationship between knowledge and behavior, the context of the learning process, patients' perception of their disease and its treatment, non‐acceptance of disease, the need for patient empowerment, perceived benefits and barriers, patient satisfaction and quality of life. Behavioral models of education are reviewed. Recommendations are provided for those planning programs about the choice between different types of program, problems of development of clear‐cut definition of objectives in behavioral terms, choice of learning methods, the use of audiovisual aids and computer based learning materials. Certain specific problems are dealt with in more detail, for example; the initiation of insulin therapy and learning about hypoglycemia. Methods of evaluation of process and outcome are described and the need for these to be repeated on a regular basis stressed. The lifelong process of education and the recognition that all carers are involved and require training in this process, are emphasized.
The Role of Glycemia in Diabetic Complications
Authors: Amiel Stephanie A.
Published: April 2004

The diabetes syndromes share hyperglycemia as a common metabolic abnormality. Microvascular complications unique to diabetes and the early and more aggressive appearance of macrovascular complications in diabetes of most types imply a common etiopathogenesis. Epidemiological evidence certainly supports the view that chronic hyperglycemia is associated with greater risk of all the diabetic complications. Despite the obvious influence of genetics and other risk factors for vascular damage, prospective randomized controlled trials that target intensified glucose control in diabetes show a striking reduction in the prevalence of micro‐ and macrovascular disease in type 1 and type 2 diabetes and of macrovascular disease in type 1, with suggestions that the glucose targets need to be lower than those achieved to date in order to have an impact upon macrovascular disease in type 2 also. These data show the importance of glucose controlper sein the minimization of complication risk in diabetes.