bluuebunny/crossref_metadata_2025 huggingface dataset:
Density functional theory study of formaldehyde oligomers
Authors: Chaudhari Ajay , Sahu Prabhat K. , Lee Shyi‐Long
Published: August 2004

Hydrogen‐bonded formaldehyde oligomers (dimer to pentamer) are studied using density functional theory (DFT), the B3LYP method, and the 6‐311+G* basis set. Many‐body interaction energies are obtained to study the contribution of many‐body terms to binding energy. The basis set superposition error (BSSE)‐corrected total energies are −229.08170, −343.61410, −458.16660, and −572.70901 hartrees for dimer, trimer, tetramer, and pentamer, respectively, with corresponding binding energies −2.55, −4.86, −6.99, and −9.49 kcal/mol. Two‐body energies have been found to contribute significantly to the total binding energy in dimer to pentamer, whereas higher‐order interaction energies are negligible. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Conventional strain energy in the oxadiazetidines
Authors: Benton Christopher W. , Magers David H.
Published: August 2004

The conventional strain energies for all four isomers of oxadiazetidine are determined within the isodesmic, homodesmotic, and hyperhomodesmotic models. Optimum equilibrium geometries, harmonic vibrational frequencies, and corresponding electronic energies are computed for all pertinent molecular systems using self‐consistent field theory, second‐order perturbation theory, and density functional theory (DFT) and employing two basis sets of triple‐zeta valence quality: 6‐311G(d,p) and 6‐311+G(2df,2pd). The DFT functional employed is Becke's three‐parameter hybrid functional using the Lee, Yang, and Paar correlation functional. Single‐point fourth‐order perturbation theory and coupled‐cluster theory restricted to single and double excitations [CCSD(T)] calculations employing the larger basis set also are computed, at both the second‐order Møller–Plesset (MP2)/6‐311G(d,p) and the MP2/6‐311+G(2df,2pd) optimized geometries, to determine the effect of higher‐order correlation effects on strain energy computation and to gauge the effect of geometry on these effects. Using the same models and methods, the conventional strain energies for both isomers of oxazetidine also are computed, to determine the effect on the strain energy of replacing a nitrogen with a carbon in the ring. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
A computer program for automated data evaluation to support in vitro higher‐throughput screening for drug metabolism and pharmacokinetics attributes
Authors: Fung Eliza N. , Chu Inhou , Nomeir Amin A.
Published: August 2004

With the advances in analytical techniques, higher‐throughput screening for drug metabolism and pharmacokinetics (DMPK) attributes has become an integral part of drug discovery. However, as the number of compounds increases, the volume of data that needs to be processed and evaluated increases exponentially. As a result, a major challenge for the analytical chemist is how to quickly process the vast amount of data so as to keep up with the throughput of the screening assay. We have developed a customized computer program for automated evaluation of the liquid chromatography/tandem mass spectrometric (LC/MS/MS) data generated from the in vitro DMPK screening assays. This program performs automatic data processing and quality control. It identifies analytical anomalies, such as low internal standard intensity and poor reproducibility of replicates. All analytical anomalies for individual compounds are summarized into an ‘E‐Log’ in a color‐coded format for reviewing. With the use of this program and other supporting software, data processing and evaluation for up to 100 compounds are accomplished in several minutes. Copyright © 2004 John Wiley & Sons, Ltd.
Method for differential detection and identification of components in protein mixtures analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Ossipova Elena , Nord Lars I. , Kenne Lennart , Eriksson Jan
Published: August 2004

We demonstrate that the semi‐quantitative information in matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectra of tryptically digested protein mixtures can, via a systematic statistical approach, be utilized for the identification of a protein present in different concentrations in two samples. Multiple mass spectra were acquired from a series of tryptically digested test samples in which the concentration of one protein was varied and the concentrations of three other proteins were held constant. The mass spectra were subjected to soft independent modeling of class analogy (SIMCA) analysis assuming that spectra originating from two different samples belonged to different data classes. The SIMCA analysis yielded information on which individual m/z values discriminate between two classes. Protein identification by proteolytic peptide mass fingerprinting was performed with different numbers of mass values in the fingerprint according to the discriminatory information, beginning with the mass corresponding to the best discrimination, followed by the best together with the second best, etc. By using the Probity algorithm, which computes the statistical significance of each identification result, we demonstrate that the first protein identified at a desired significance level (0.001) is the protein that was present in a different concentration in the two samples. Differential analysis of expression is often performed by comparing 2D‐gel‐spot intensities followed by mass spectrometric identification of the respective protein in each spot that differs. The method presented here has the potential to allow identification of the protein component that differs in cases where a gel‐spot is poorly resolved and contains several proteins. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of sodium dodecyl sulfate micelles on peptide mass fingerprinting by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Tummala Rama , Limbach Patrick A.
Published: August 2004

Here we have examined the effect of sodium dodecyl sulfate (SDS) at various concentrations on matrix‐assisted laser desorption/ionization (MALDI) peptide mass fingerprinting experiments. Several model proteins were digested with trypsin and then various amounts of SDS were added prior to MALDI mass spectrometry. Evaluation of the data was made by calculating the amino acid sequence coverage within each analysis. It was found that addition of 0.1–0.3% w/v SDS prior to MALDI analysis results in an increase in the number of tryptic peptides detected thereby improving the total sequence coverage of the analysis. The use of SDS at concentrations near its critical micelle concentration can improve sequence coverage from MALDI peptide mass fingerprinting analyses allowing for increased confidence in protein identification or additional opportunities to identify putative regions of posttranslational modification. Copyright © 2004 John Wiley & Sons, Ltd.
On‐line laser desorption/ionization mass spectrometry of matrix‐coated aerosols
Authors: Jackson Shelley N. , Mishra Sushama , Murray Kermit K.
Published: August 2004

Matrix‐assisted laser desorption/ionization (MALDI) was used for the on‐line analysis of single particles. An aerosol was generated at atmospheric pressure and particles were introduced into a time‐of‐flight (TOF) mass spectrometer through a single‐stage differentially pumped capillary inlet. Prior to entering the mass spectrometer, a matrix was added to the particles using a heated saturator and condenser. A liquid matrix, 3‐nitrobenzyl alcohol (NBA), and a solid matrix, picolinic acid (PA), were used. Particles were ablated with a 351 nm excimer laser and the resulting ions were mass‐separated in a two‐stage reflectron TOF mass spectrometer. Aerosol particles containing the biomolecules erythromycin and gramicidin S were analyzed with and without the matrix addition step. The addition of NBA to the particles resulted in mass spectra that contained an intact molecular ion mass peak. In contrast, PA‐coated particles did not yield molecular ion peaks from matrix‐coated particles. Copyright © 2004 John Wiley & Sons, Ltd.
Single‐drop microextraction and gas chromatography/mass spectrometric determination of anisaldehyde isomers in human urine and blood serum
Authors: Liu Bo‐Min , Malik Pridap , Wu Hui‐Fen
Published: August 2004

The application of single‐drop microextraction (SDME) followed by gas chromatography/chemical ionization mass spectrometry (GC/CI‐MS) was investigated for the determination of anisaldehyde isomers in human urine and blood serum. The effects of extraction solvent, sample agitation rate, salt addition, sampling time and temperature on the extraction efficiency were examined and optimized. Analytical parameters such as linearity, reproducibility, detection limit and relative recovery were evaluated under the optimized experimental conditions. Good reproducibilities of replicate extractions (n = 5) were obtained, with relative standard deviation (RSD) values below 6%. The limits of detection (LOD) using an extraction time of 5 min were found to be in the range 2–5 ng/mL under the selected ion monitoring (SIM) mode of GC/MS. Recoveries of 82–98% were achieved after 5 min extraction. Copyright © 2004 John Wiley & Sons, Ltd.
Stability of porphyrin–calix[4]arene complexes analyzed by electrospray ionization mass spectrometry
Authors: Arai Satoshi , Ishihara Shinsuke , Takeoka Shinji , Ohkawa Haruki , Shibue Toshimichi , Nishide Hiroyuki
Published: August 2004

The stability of some porphyrin–calix[4]arene sodium‐ion complexes were determined by a collision‐activated decomposition (CAD) method utilizing electrospray ionization mass spectrometry (ESI‐MS). Comparing the values of E1/2, the collision energy at which the relative intensity of the complex ion is 0.5, we found that the porphyrin‐calix[4]arene complex with the higher value of E1/2 corresponded to that with the larger association constant (Kass), as measured by 1H‐NMR in CDCl3. Both our ESI‐MS and NMR studies proved that the number of hydrogen bonds and the rigidity of the calix[4]arene stabilized the complex. The ESI‐MS technique could be successful in screening the binding affinity in host–guest systems with a small amount of sample. Copyright © 2004 John Wiley & Sons, Ltd.
Mass spectral study of meso‐alkyl and meso‐cycloalkyl calix(4)pyrroles under electron impact conditions
Authors: Prabhakar S. , Radha Kishan M. , Mirza S. P. , Raghavan K. V. , Vairamani M.
Published: August 2004

A series of meso‐cycloalkyl calix(4)pyrroles (I) and meso‐dialkyl calix(4)pyrroles (II) has been studied under electron ionization (EI) mass spectral conditions. All the calix(4)pyrroles showed prominent molecular ions. The cleavage of the CC bond linked at position 2 of the pyrrole ring (β‐cleavage) is the foremost and dominant fragmentation process. The β‐cleavage process, either through ring opening or directly, results in the loss of an alkyl radical from the molecular ion. The collision‐induced dissociation (CID) spectra of I showed specific sequential expulsion of pyrrole and/or cycloalkyl rings from the molecular ion with or without hydrogen migrations, revealing more information on the structure of individual compounds than was available from the EI spectra. The isomeric cycloalkyl calix(4)pyrroles showed distinguishable CID spectra, indicating structure specificity in initial ring opening whereas, in the case of II, the EI mass spectrum contains all the structure‐indicative fragment ions. The CID spectra of II resulted in a dominant [M–R]+ ion, with other characteristic ions being less abundant. Copyright © 2004 John Wiley & Sons, Ltd.
Isolation and Partial Characterization of Mexican Oxalis tuberosa Starch
Authors: Hernández‐Lauzardo Ana Niurka , Méndez‐Montealvo Guadalupe , Velázquez del Valle Miguel Gerardo , Solorza‐Feria Javier , Bello‐Pérez Luis Arturo
Published: August 2004

The chemical, physicochemical and rheological characteristics of Oxalis tuberosa starch were investigated. Oxalis starch presented an apparent amylose content of 33%, similar to maize starch used as control, with a granule size between 25–50 μm with oval and elliptical shapes and A‐type X‐ray diffraction pattern. The gelatinization temperature of oxalis starch was 64.0°C, that was lower than the one determined in maize starch (73.0°C), with an enthalpy value of 12.2 J/g, which was similar to that of maize starch.

Both oxalis and maize starch pastes behaved as weak viscoelastic systems with the elastic character (G′) predominating over the viscous character (G′′). An increase in the level of solids in the pastes increased the values of the moduli. The results suggest that heating the systems (gelatinization), causes a more pronounced enhancement in the structure of the maize starch pastes than in that of oxalis starch pastes.

Overall, it was concluded that due to its physicochemical, functional and rheological properties, Oxalis starch could be suitable for testing its use in the cosmetic and in the food industry.
Development and Physicochemical Characterization of New Resistant Citrate Starch from Different Corn Starches
Authors: Xie Xueju (Sherry) , Liu Qiang
Published: August 2004

Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high‐amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High‐amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC thermogram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the thermograms. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the thermograms when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.
Effect of Protease Addition on Starch Recovery from Steeped Sorghum and Maize
Authors: Mezo‐Villanueva Martha , Serna‐Saldívar Sergio O.
Published: August 2004

The effect of protease addition on starch recovery from steeped white regular sorghum (RSOR) compared to yellow maize (YMZ) was determined. An in vitro wet milling method standardized to test dosages from 0 to 1.5 Anson units (AU/100 g grain) indicated that starch yields increased proportionally as enzyme concentration increased. The yields were significantly lower for RSOR. A factorial experiment with a level of confidence of P < 0.05 was performed to study the effect of protease addition (1.25 AU/100 g grain) to coarsely ground kernels for 4 h after 20 h or 44 h SO2 steeping of whole grains. Calcium oxide (CaO) was used to increase the pH of the steep solution to 5.5 and improve enzyme activity. The in vitro and laboratory tests indicated that the enzyme treatment significantly improved starch yields and recoveries; the effect being more pronounced in RSOR. Protease‐treated kernels yielded 3.2% more starch than those steeped regularly. RSOR steeped for 20 h and then treated with the enzyme for 4 h yielded 6.7% more starch than the counterparts steeped regularly. When steep times were compared, kernels soaked regularly for 48 h produced 1.6% more starch than counterparts steeped for 24 h. The protease treatment reduced the amount of inseparables (gluten‐starch complexes) to zero and also lowered the gluten content of starch by about 1.5%. A comparison of protein and ash contents for the refined starches indicated that the process was more efficient for YMZ than for RSOR and for grains steeped regularly for 48 h. YMZ starch started gelatinization at a lower temperature, required less time to reach peak viscosity and had less shear thinning than RSOR.
Color Doppler velocimetry and three‐dimensional color power angiography of cervical carcinoma
Authors: Testa A. C. , Ferrandina G. , Distefano M. , Fruscella E. , Mansueto D. , Basso D. , Salutari V. , Scambia G.
Published: August 2004

Objectives

To investigate the blood flow within invasive cervical carcinoma by transvaginal two‐dimensional (2D) color spectral Doppler and three‐dimensional (3D) color power angiography and to correlate these parameters with the clinicopathological characteristics.

Methods

Seventy‐four patients with invasive cervical carcinoma were enrolled for the analysis. Squamous cell carcinoma serum antigen levels (SCC) were obtained for all the patients. Sections of all malignant tissues were analyzed for tumor expression of cyclooxygenase‐2 (COX‐2). All patients underwent color and spectral Doppler examination and 44 patients had 3D color power angiography. Color spectral Doppler parameters (color score, lowest resistance index (RI), highest peak systolic velocity (PSV)) and 3D color power angiography indices (relative color, average color, flow measure) of FIGO I/II cervical cancers were compared with those obtained in a control group of 24 patients with a normal uterine cervix. Pulsed Doppler parameters and the 3D vascular indices were compared with clinicopathological parameters, SCC serum antigen levels and tumor COX‐2 expression.

Results

At color Doppler analysis 72 patients (97%) showed intralesional detectable vessels. Color spectral Doppler and 3D‐derived parameters were significantly different in FIGO I/II cervical cancers compared with those in women with a normal cervix. A significantly higher color score (P = 0.0008), lower RI (P = 0.032) and higher PSV (P = 0.004) were associated with a tumor diameter ≥4 cm compared with smaller tumors. The highest PSV was significantly higher in patients with FIGO stage III/IV compared with FIGO stage I/II (P = 0.0069). There was a direct correlation between PSV and SCC (r = +0.44, P = 0.003). The median relative color was significantly higher in patients with a higher color score (P = 0.0006). No statistically significant correlations were found between 3D color power angiography parameters and the clinicopathological characteristics or between the 3D vascular parameters and biological factors.

Conclusions

Alterations of 3D ultrasound‐derived vascular indices were found in patients with cervical cancer compared with those with a normal cervix. Moreover, some vascular indices proved to be associated with tumor size. The assessment of a possible clinical role of 2D and 3D ultrasound‐derived vascular indices in cervical cancer deserves further investigation. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Doppler assessment of cardiac function at 11–14 weeks' gestation in fetuses with normal and increased nuchal translucency
Authors: Huggon I. C. , Turan O. , Allan L. D.
Published: August 2004

Objective

To investigate cardiac dysfunction as a potential underlying mechanism for increased nuchal translucency (NT) in fetuses with chromosomal abnormality or heart defects.

Methods

Myocardial performance index (MPI) and atrioventricular valve E/A ratios for both sides of the heart were measured by Doppler echocardiography in fetuses at 11–14 weeks' gestation. The study groups consisted of 159 normal control fetuses, 199 otherwise normal fetuses but with increased NT ≥ 4 mm, 142 fetuses with trisomy 21, 58 with trisomy 18, 19 with trisomy 13, 37 with Turner's syndrome and 24 with isolated heart defects. Groups were compared using Student's t‐test and confidence intervals for differences between groups were calculated.

Results

Otherwise normal fetuses with increased NT showed no difference in any of the cardiac Doppler parameters from normal controls. Mean E/A ratio was slightly but significantly increased in trisomy 21 fetuses compared with normal controls (0.604 vs. 0.578 on the right, P = 0.011; 0.581 vs. 0.542 on the left, P = 0.0001). E/A ratio was not significantly different between any of the other groups and the normals but there was a small increase in absolute E‐wave velocity in trisomy 18 fetuses. MPI was significantly decreased in trisomy 21 fetuses, (0.330 vs. 0.378, P = 0.002 on the left) and also in Turner's syndrome fetuses (0.301 vs. 0.352 on the right, P = 0.04; 0.320 vs. 0.378 on the left, P = 0.034) implying better performance, but not in the other groups.

Conclusions

The magnitude and/or direction of the differences shown do not support a major role for cardiac functional abnormality in the development of NT. Important cardiac dysfunction could not be demonstrated in association with increased NT in normal or abnormal fetuses. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Lanthanzirkonat: ein innovatives Wärmedämmschichtmaterial. Lanthanum zirconate: an innovative Thermal Barrier Material
Authors: Lugscheider Erich , Bobzin Kirsten , Lackner Kristijan
Published: August 2004

In diesem Bericht werden die Arbeiten des Forschungsprojekts AiF‐13114 N/1 beschrieben. Im Rahmen des Forschungsvorhabens wurden mittels der Electron Beam Physical Vapour Deposition (EB‐PVD) Schichtsysteme auf Basis der Verbindungen Lanthanzirkonat und Zirkoniumdioxid (YSZ) entwickelt und deren Potenziale für die Anwendung als Wärmedämmschichten (WDS) in der Gastur‐binenapplikation ausgeleuchtet. Basis der Schichtentwicklung war die Verwendung von Lanthanoxid und Yttriumoxid teilstabilisierten Zirkoniumdioxids (YSZ) als pulverförmiges Ausgangsmaterial, welches in einer EB‐PVD‐Anlage aus einem Zweirillen Kupfertiegel verdampft wurde. Es wurden Prozessparameter ermittelt, mit denen langzeitbeständige, kolumnare Lanthanzirkonat EB‐PVD‐Schichten mit einer höheren Phasenstabilität, niedrige Wärmeleitfähigkeit und höheren Sinterträgheit hergestellt werden können, die die Möglichkeit bieten, die Oberflächentemperatur der 1. Turbinenstufe in Gasturbinenanlagen zu steigern [1, 2, 3, 4, 5, 6]. YSZ, eine seit 1989 eingesetzte WDS, wurde als Referenzsystem für die durchgeführten Untersuchungen verwendet. Als Grundwerkstoff wurde die Nickelbasislegierung Inconel Alloy 600 eingesetzt. Bruchgefüge und Topografie der entwickelten Schichtsysteme wurden mittels Rasterelektronenmikroskopie charakterisiert. Mit dem Verfahren der Nanoindentation ist es gelungen, den Steifigkeitsverlauf entlang der Kolumnen zu bestimmen. Mittels Thermozyklustest wurde die Thermowechselbeständigkeit ermittelt.
Disilynes. III [1] A Relatively Stable Disilyne RSi≡SiR (R = SiMe(SitBu3)2)
Authors: Wiberg Nils , Vasisht Sham Kumar , Fischer Gerd , Mayer Peter
Published: August 2004

The disilyne R**Si≡SiR** (R** = SiMe(SitBu3)2), prepared as the first isolable and realtively stable silicon compound with a SiSi triple bond two years ago by dehalogenation of trans‐R**ClSi=SiClR** with LiC10H8 in thf at ‐78 °C (calc.: Si≡Si distance 2.072Å, Si‐Si≡Si bond angle 148°), forms with CH2=CH2 a [2+2] and with CH2=CH‐CH=CH2 a [2+4] cycloadduct. The ethene adduct takes up oxygen very easily with change of the Si=Si group into a SiOSiO ring with formation of R**Si(μ‐O)(μ‐O)(μ‐C2H4)SiR**. By heating the disilyne in heptane to ca. 50 °C in the presence of traces of thf it transforms into a monoxide of the ethene adduct with formation of R**Si(μ‐O)(μ‐C2H4)SiR**. In thf, the disilyne rearranges at r.t. and below by migration of a SitBu3 group with formation of a silyl substituted cyclotrisilene. X‐ray structure determinations of the ethene adduct and its mono‐ and dioxide are presented.
On the Gabai-Eliashberg-Thurston Theorem
Authors: Honda Ko , Kazez William H. , Matić Gordana
Published: August 2004

We present a new, completely three-dimensional proof of the fact, due to the combined work of Gabai and Eliashberg-Thurston, that every closed, oriented, connected, irreducible 3-manifold with nonzero second homology carries a universally tight contact structure.
Combinatorics of rational singularities
Authors: Dũng Tráng Lê , Tosun Meral
Published: August 2004

A normal surface singularity is rational if and only if the dual intersection graph of a desingularization satisfies some combinatorial properties. In fact, the graphs defined in this way are trees. In this paper we give geometric features of these trees. In particular, we prove that the number of vertices of valency greater than 3 in the dual intersection tree of the minimal desingularization of a rational singularity of multiplicity m greater than 3 is at most m - 2.
On the equation of degree 6
Authors: De Concini Corrado , Procesi Claudio , Salvetti Mario
Published: August 2004

In this paper we study the Schwarz genus for the covering of the space of polynomials with distinct roots by its roots. We show that, for the first unknown case (degree 6), the genus is strictly less than the one predicted by dimension arguments, contrary to what happens in all other reflection groups.
Rohlin's invariant and gauge theory, I. Homology 3-tori
Authors: Ruberman Daniel , Saveliev Nikolai
Published: August 2004

This is the first in a series of papers exploring the relationship between the Rohlin invariant and gauge theory. We discuss a Casson-type invariant of a 3-manifold Y with the integral homology of the 3-torus, given by counting projectively flat U(2)-connections. We show that its mod 2 evaluation is given by the triple cup product in cohomology, and so it coincides with a certain sum of Rohlin invariants of Y. Our counting argument makes use of a natural action of H^1 (Y;Z_2) on the moduli space of projectively flat connections; along the way we construct perturbations that are equivariant with respect to this action. Combined with the Floer exact triangle, this gives a purely gauge-theoretic proof that Casson's homology sphere invariant reduces mod 2 to the Rohlin invariant.
Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörungen
Authors: Hampel Petra , Petermann Franz
Published: August 2004

Zusammenfassung. Hyperkinetische Störungen bzw. die Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen (ADHS) gehören zu den häufigsten psychischen Auffälligkeiten im Kindesalter. Durch ihre recht hohe Persistenz stellen sie ein beträchtliches Entwicklungsrisiko dar. Es wird der aktuelle Stand der klinischen Forschung zur Epidemiologie, Ätiologie sowie Intervention der ADHS zusammengefasst. Außerdem werden aktuelle Trends vorgestellt, die sich in aktuellen Beiträgen zu neurobiologischen, neuropsychologischen und klinisch-psychologischen Fragestellungen widerspiegeln.
Neurobiologie der Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörung (ADHS)
Authors: Banaschewski Tobias , Roessner Veit , Uebel Henrik , Rothenberger Aribert
Published: August 2004

Zusammenfassung. Bei der Aufmerksamkeitsdefizit-Hyperaktivitätsstörung (ADHS) handelt es sich um eine in der Kindheit beginnende, klinisch und wahrscheinlich auch ätiologisch heterogene Störung, die durch die Symptom-Trias Unaufmerksamkeit, Hyperaktivität und Impulsivität gekennzeichnet ist. Obwohl die genauen neurobiologischen Ursachen der ADHS weiterhin unbekannt sind, konnten in den Forschungsbereichen Genetik, psychosoziale Umweltfaktoren, Neuropsychologie, Psychophysiologie, funktionelle und strukturelle Bildgebung und Biochemie bedeutende Fortschritte erzielt und verschiedene, hypothetische Modelle zur Pathophysiologie entwickelt werden. Die vorliegende Übersichtsarbeit fasst die aktuellen Erkenntnisse der unterschiedlichen Gebiete zusammen und gibt so eine Zusammenfassung über den aktuellen Wissensstand zur Pathophysiologie der ADHS.
Wirken sich unterschiedliche Verstärkerbedingungen bei Kindern mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen auf psychophysiologische Kennwerte aus?
Authors: Hampel Petra , Petermann Franz , Mohr Beate , Bonkowski Matthias , Mönter Christiane
Published: August 2004

Zusammenfassung. Kinder und Jugendliche mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen (ADHS) zeigen in experimentellen Versuchsanordnungen eine Schwäche, Handlungsimpulse zu unterdrücken. Hierbei wird diskutiert, ob diese gestörte Verhaltenshemmung auf eine Störung in der exekutiven Hemmung oder auf ein motivationales Defizit zurückgeführt werden kann. In dieser Pilotstudie sollte insbesondere die Durchführbarkeit einer modifizierten Go/Nogo-Aufgabe mit vier verschiedenen Verstärkerbedingungen geprüft werden: Belohnung, Bestrafung, kombinierte Belohnung/Bestrafung sowie eine Bedingung ohne sekundäre Verstärkung. Die Effekte der vier Verstärkerbedingungen auf Fehlerraten, aufgabenbezogene Maße, aktuelles Befinden und peripherphysiologische Kennwerte wurden an 16 weiblichen und 16 männlichen gesunden Kontrollen im Alter zwischen 8 und 12 Jahren geprüft. Außerdem wurden 8 Jungen mit ADHS im Vergleich zu 8 gesunden Jungen untersucht. Es ergaben sich keine Geschlechtseffekte, aber Haupteffekte der Bedingung für die Gesunden. Unter Bestrafung waren die Auslassungsfehler signifikant erhöht, die Aufgabenbewertung und die Leistungseinschätzung erniedrigt. Die Herzrate war unter Belohnung und unter Lohn/Strafe erhöht. Die klinische und gesunde Gruppe unterschieden sich nicht in den Kennwerten. Post hoc t-Tests ergaben erwartungsgemäß nur in der Bedingung ohne Verstärkung tendenziell erhöhte Fehlreaktionen bei der klinischen Gruppe im Vergleich zu den Gesunden. Die Ergebnisse sprechen für eine Durchführbarkeit der motivationalen Go/Nogo-Aufgabe, legen aber auch einige Modifikationen nahe (z. B. Erhöhung des Geldanreizes unter Belohnung).
Unterrichtsverhalten von Kindern mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen
Authors: Lauth Gerhard W. , Mackowiak Katja
Published: August 2004

Zusammenfassung. In der vorliegenden Untersuchung wird das Unterrichtsverhalten einer Gruppe von klinisch auffälligen Kindern mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen (ADHS) mit dem Verhalten unauffälliger Kinder verglichen. Die Auswahl der aufmerksamkeitsgestörten/hyperaktiven Kinder erfolgte aus einer Grundgesamtheit von 569 Grundschülern anhand von DSM III-R Kriterien (Lehrerbeurteilung) und der Teacher Rating Scale ( Conners, 1969 ). 55 derart auffällige Kinder wurden mit einer Stichprobe von 55 Kindern ohne ADHS (Kontrollgruppe) parallelisiert (matched pairs). Das Unterrichtsverhalten wurde anhand des Münchner Aufmerksamkeitsinventars (MAI; Helmke, 1988 ; Helmke & Renkl, 1992 ) beobachtet. Dieses Instrument erfasst sowohl negative als auch angemessene, unterrichtsförderliche Verhaltensweisen sowie den Unterrichtskontext (z. B. mehr oder weniger stark strukturierte Situationen). Ein Vergleich der beiden Gruppen zeigt, dass sich aufmerksamkeitsgestörte und nicht-aufmerksamkeitsgestörte Grundschüler deutlich unterscheiden. Die auffälligen Kinder erweisen sich in allen Verhaltenskategorien als aktiver und störender und zeichnen sich vor allem durch einen Mangel an anforderungskonformen Verhaltensweisen aus. Die Analyse der Kontextbedingungen weist darauf hin, dass unterschiedliche Kontexte durchaus einen Einfluss auf das Verhalten der Kinder im Unterricht haben; allerdings zeigen sich keine differenziellen Effekte für ADHS- und Kontrollkinder. Die Korrelationen zwischen Lehrerurteilen und dem beobachteten Unterrichtsverhalten sind durchgehend signifikant, wobei das anforderungsgemäße Unterrichtsverhalten am höchsten mit dem Lehrerurteil korreliert und einen bedeutsamen Prädiktor für das Lehrerurteil darstellt.
EEG - Feedback für Kinder mit einer Aufmerksamkeitsdefizit- und Hyperaktivitätsstörung (ADHS)
Authors: Strehl Ute , Leins Ulrike , Danzer Nadine , Hinterberger Thilo , Schlottke Peter F.
Published: August 2004

Zusammenfassung. Die Therapie von Kindern mit einer Aufmerksamkeitsdefizit- und Hyperaktivitätsstörung (ADHS) mithilfe von EEG-Feedback knüpft an die Annahme einer Beeinträchtigung der zentralnervösen Aktivierungsregulation an. Neben dem bislang praktizierten Feedback zur Veränderung bestimmter EEG-Frequenzen (meistens in den Frequenzbändern von Theta und Beta) wird erstmals in einem einfach-blinden Design eine zweite Methode eingesetzt: das Feedback der langsamen kortikalen Potenziale (LP). Eine erste Auswertung für 19 Kinder, die ein solches LP-Training absolviert haben, sowie für 8 Kinder im Theta-Beta-Feedback, zeigt ein halbes Jahr nach Ende des Trainings für beide Gruppen signifikante Veränderungen im Verhalten, der Aufmerksamkeit sowie in der Ausprägung des Intelligenzquotienten. Der Erwerb von Selbstkontrolle der jeweiligen EEG-Parameter, gemessen als Trefferquote, verläuft hingegen unterschiedlich. Während die LP-Gruppe eine stetige Verbesserung im Verlauf zeigt, ist die Theta-Beta-Gruppe schon in der ersten von drei Trainingsphasen erfolgreich, ohne sich jedoch weiter zu steigern.
Personality, Cardiovascular Disease, and Cancer:
Authors: Amelang Manfred , Hasselbach Petra , Stürmer Til
Published: August 2004

Abstract. Ten years ago a sample of N = 5.133 male and female subjects (age 28-74) responded to questionnaires including scales for personality, life style, work stress as well as questions on prevalent disease. We now report on the follow-up regarding self-reported incidence of cardiovascular disease and cancer. During a mean follow-up of 10 years, 257 participants had died. Of those alive, N = 4.010 (82%) participated in the follow-up. Of these, 120 and 180 persons reported incident cardiovascular disease and cancer, respectively. The incidence of cardiovascular disease could be significantly predicted by the personality factors “Emotional Lability”, “Behavioral Control” and “Type-A-Behavior” as well as by the “Rationality/Antemotionality”-scale according to Grossarth-Maticek. After controlling for age, gender and smoking behavior only the significant effect of “Emotional Lability” remained and the predictors according to Grossarth-Maticek had no incremental validity. Cancer could not be predicted by any personality factors.
Unzufriedenheit mit dem eigenen Gewicht nach Reduktionsdiät bei Frauen und Männern:
Authors: Mönnichs Gabriele , von Lengerke Thomas
Published: August 2004

Zusammenfassung. Es werden Unzufriedenheit mit und Einschränkung durch Körpergewicht in Abhängigkeit von Diätverhalten zur Gewichtsreduktion, Diätfolgen, Übergewicht, soziodemographischen Variablen und Lebensstil untersucht. Daten der 4261 Teilnehmer des KORA-Survey 2000 wurden mittels logistischer Regressionen bzgl. der Zusammenhänge von Diätverhalten, Diäterfolg, Jojo-Effekt, BMI, Alter/Familienstand/Sozialschicht/Wohnort und Rauchen/Alkoholkonsum/Bewegung/Ernährung mit gewichtsbedingter Unzufriedenheit und Einschränkung analysiert. Unzufriedenheit mit dem Körpergewicht nimmt mit steigendem BMI zu; gleichzeitig sind Jüngere und Männer höherer sozialer Schichten unzufriedener, wohingegen bei Frauen keine soziale Stratifizierung auftritt. Personen, die im letzten Jahr eine Reduktionsdiät gemacht hatten, waren unzufriedener als Personen ohne Diät, wobei dieser Zusammenhang durch die Subgruppen, die keinen Diäterfolg und/oder Jojo-Effekt-Erfahrungen hatten, erklärbar ist. Die Ergebnisse für gewichtsbedingte Einschränkungen sind entsprechend, allerdings weniger ausgeprägt. Diätverhalten und Diätmisserfolg sind eigenständige, von Übergewicht unabhängige Korrelate der Unzufriedenheit mit und Einschränkung durch Körpergewicht. Die Arbeit ergänzt die klinisch orientierte Forschung zum Zusammenhang zwischen Körperwahrnehmung und (Über-)Gewicht durch einen bevölkerungsbezogenen Ansatz.
Global dayside ionospheric uplift and enhancement associated with interplanetary electric fields
Authors: Tsurutani Bruce , Mannucci Anthony , Iijima Byron , Abdu Mangalathayil Ali , Sobral Jose Humberto A. , Gonzalez Walter , Guarnieri Fernando , Tsuda Toshitaka , Saito Akinori , Yumoto Kiyohumi , Fejer Bela , Fuller‐Rowell Timothy J. , Kozyra Janet , Foster John C. , Coster Anthea , Vasyliunas Vytenis M.
Published: August 2004

The interplanetary shock/electric field event of 5–6 November 2001 is analyzed using ACE interplanetary data. The consequential ionospheric effects are studied using GPS receiver data from the CHAMP and SAC‐C satellites and altimeter data from the TOPEX/Poseidon satellite. Data from ∼100 ground‐based GPS receivers as well as Brazilian Digisonde and Pacific sector magnetometer data are also used. The dawn‐to‐dusk interplanetary electric field was initially ∼33 mV/m just after the forward shock (IMF BZ = −48 nT) and later reached a peak value of ∼54 mV/m 1 hour and 40 min later (BZ = −78 nT). The electric field was ∼45 mV/m (BZ = −65 nT) 2 hours after the shock. This electric field generated a magnetic storm of intensity DST = −275 nT. The dayside satellite GPS receiver data plus ground‐based GPS data indicate that the entire equatorial and midlatitude (up to ±50° magnetic latitude (MLAT)) dayside ionosphere was uplifted, significantly increasing the electron content (and densities) at altitudes greater than 430 km (CHAMP orbital altitude). This uplift peaked ∼2 1/2 hours after the shock passage. The effect of the uplift on the ionospheric total electron content (TEC) lasted for 4 to 5 hours. Our hypothesis is that the interplanetary electric field “promptly penetrated” to the ionosphere, and the dayside plasma was convected (by E × B) to higher altitudes. Plasma upward transport/convergence led to a ∼55–60% increase in equatorial ionospheric TEC to values above ∼430 km (at 1930 LT). This transport/convergence plus photoionization of atmospheric neutrals at lower altitudes caused a 21% TEC increase in equatorial ionospheric TEC at ∼1400 LT (from ground‐based measurements). During the intense electric field interval, there was a sharp plasma “shoulder” detected at midlatitudes by the GPS receiver and altimeter satellites. This shoulder moves equatorward from −54° to −37° MLAT during the development of the main phase of the magnetic storm. We presume this to be an ionospheric signature of the plasmapause and its motion. The total TEC increase of this shoulder is ∼80%. Part of this increase may be due to a “superfountain effect.” The dayside ionospheric TEC above ∼430 km decreased to values ∼45% lower than quiet day values 7 to 9 hours after the beginning of the electric field event. The total equatorial ionospheric TEC decrease was ∼16%. This decrease occurred both at midlatitudes and at the equator. We presume that thermospheric winds and neutral composition changes produced by the storm‐time Joule heating, disturbance dynamo electric fields, and electric fields at auroral and subauroral latitudes are responsible for these decreases.
Mathematical analysis of the stratospheric photochemical system
Authors: Yang Peicai , Brasseur Guy P.
Published: August 2004

The impact of odd chlorine (Cly) and odd nitrogen (NOy) perturbations (resulting from human activities) and of enhanced H2O‐H2SO4 aerosol load (associated with volcanic activity) on stratospheric ozone (25 km altitude, midlatitudes) is assessed by using a chemical box model in which key heterogeneous reactions on the surface of sulfate aerosol particles are taken into account. The model shows that if transport is ignored, the response of the photochemical system to increased abundances of odd chlorine and odd nitrogen and to enhanced aerosol surface area density is characterized by a multiequilibrium regime. Catastrophic transitions may occur and may produce dramatic reductions in the stratospheric ozone concentration. When the dissipative effects associated with transport are taken into account, the system still exhibits a nonlinear response to external nitrogen and chlorine sources but without multiequilibrium solutions or catastrophic transitions. Over a sensitive interval, small external disturbances applied to model parameters can lead to large changes in the state of the system. For example, the large drop in ozone derived by the model when dissipative transport effects are taken into account corresponds to a degeneracy of the multiequilibrium regime found when dissipative terms are omitted.
Dynamic interactions between erosion, deposition, and three‐dimensional deformation in compressional fold belt settings
Authors: Simpson Guy
Published: August 2004

This study investigates whether the three‐dimensionality of erosion and deposition can influence three‐dimensional folding, even when compression is purely convergent. This problem is studied by employing a three‐dimensional mathematical model incorporating dynamic thin‐plate deformation coupled with fluvial and hillslope sediment transport. The approach taken is to impose several fundamentally different sediment routing patterns (by changing the initial regional topographic slope, β, and the ratio of the characteristic timescales for deformation to fluvial surface processes, R) and to investigate how deformation responds. Numerical results indicate that when β and/or R are small (i.e., initial topography is regionally flat and/or rates of surface processes are slow compared to rate of imposed deformation), folding is two‐dimensional and unaffected by surface processes since loads created by surface processes are imposed after deformation. This situation favors development of small‐scale drainage networks transporting sediment from anticlines to adjacent basins. When β and/or R are relatively large, the development of a large‐scale transverse drainage network, which can be maintained during folding, is able to strongly amplify and localize folding. This leads to interesting features where the largest transverse rivers coincide with the greatest structural and topographic amplitude of doubly plunging folds, which is caused by erosion‐enhanced deformation. For intermediate parameter values, folding and surface processes interact in a complex manner, giving rise to three‐dimensional en echelon structures that migrate in a transient manner. This study demonstrates that under some circumstances, one can anticipate major two‐way interaction between surface processes and three‐dimensional deformation.
Glass compositions, plume‐ridge interaction, and hydrous melting along the Galápagos Spreading Center, 90.5°W to 98°W
Authors: Cushman Buffy , Sinton John , Ito Garrett , Eaby Dixon Jacqueline
Published: August 2004

The Galápagos Spreading Center (GSC) between 90.5°W and 98°W manifests its interaction with the nearby Galápagos plume by way of variations in lava geochemistry, crustal thickness, and morphology along the ridge axis. Natural glasses from stations with ∼9 km average spacing were analyzed for major and minor elements, H2O, and CO2. Samples can be classified as enriched mid‐ocean ridge basalts (E‐MORB), transitional MORB (T‐MORB), or normal MORB (N‐MORB) on the basis of K/Ti ratios. E‐MORB dominate the GSC east of 92.6°W. T‐MORB are mainly found between 92.6°W and 95.5°W. West of the propagating rift tip at 95.5°W, N‐MORB dominate. High K/Ti E‐MORB also have higher H2O, Al2O3, and Na2O and lower FeO*, SiO2, and CaO/Al2O3 relative to N‐MORB at similar values of MgO, characteristics consistent with lower mean extents of partial melting relative to N‐MORB. We examine the melting process along this section of the GSC with a set of equations that simulate a deep zone of hydrous melting related to the depression of the mantle solidus by H2O. This model constrains the range of mantle source compositions, the depth of the additional hydrous melting zone, the melt productivity in the hydrous region, and the ratio of mantle flow rate through the hydrous zone relative to the anhydrous zone (Uw/U0) that can explain the measured crustal thickness as well as the fractionation‐corrected concentrations of K, Na2O, H2O, and Ti along the GSC. Far from the hot spot, the measured crustal thickness and N‐MORB compositions are explained by passive mantle upwelling (Uw/U0 = 1), mean melt fraction () ∼ 0.06, and a source with ∼35 ppm K, 130 ppm H2O, 2300 ppm Na2O, and 1050 ppm Ti. The transitional zone has a source enriched in K and could have a slight excess plume‐driven flow through the hydrous melting zone (Uw/U0 ≤ 1.5). The crustal thickness and glass compositions in the “enriched” region of the GSC nearest the hot spot are best explained by only a slight increase in the temperature of the mantle (<∼20°C), coupled with a mantle source moderately enriched (relative to N‐MORB source) and plume‐driven flow through the hydrous zone of Uw/U0 = 1.5–3.5.
Century‐scale solar variability and Alaskan temperature change over the past millennium
Authors: Wiles Gregory C. , D'Arrigo Rosanne D. , Villalba Ricardo , Calkin Parker E. , Barclay David J.
Published: August 2004

Correlation of geologic histories from 130 Alaskan glaciers with a record of solar variation suggests that multi‐decadal to century‐scale temperature variations in the North Pacific and Arctic sectors have been influenced by solar forcing over the past thousand years. Mountain glacier fluctuations are primarily a record of summer cooling and the composite glacial history from three climatic regions across Alaska shows ice expansions approximately every 200 years, compatible with a solar mode of variability. The modulating effects of the cold phases of the Pacific Decadal Oscillation and the Arctic Oscillation may, when in phase with decreased solar activity, serve to amplify cooling, forcing glacier advance.
Intrusion of the Bay of Bengal water into the Arabian Sea during winter monsoon and associated chemical and biological response
Authors: Prasanna Kumar S. , Narvekar Jayu , Kumar Ajoy , Shaji C. , Anand P. , Sabu P. , Rijomon G. , Josia J. , Jayaraj K. A. , Radhika A. , Nair K. K. C.
Published: August 2004

Situated in similar latitudes and subjected to similar atmospheric forcing, the tropical basins of the Arabian Sea looses fresh water due to excess evaporation over precipitation while Bay of Bengal receives freshwater via excess rain and river run off. The hydrological imbalance thus created on an annual scale will have to be balanced by the inter‐basin exchange. In winter this happens through the intrusion of Bay of Bengal waters into the Arabian Sea, when the southward flowing East India Coastal Current carrying low salinity waters from the northern Bay feeds into the West India Coastal Current flowing north along the shelf in the Arabian Sea. Advection of nutrients by this intrusion triggers enhanced levels of chlorophyll near the southern part of the western shelf of India and may play a role in altering the biogeochemistry of this intense hypoxic region.
Wind ringing of the ocean in presence of mesoscale eddies
Authors: Klein P. , Lapeyre G. , Large W. G.
Published: August 2004

Recent findings have highlighted the impact of high frequency (HF) winds on the inertial motions and the consequences on the large‐scale oceanic circulation [Wunsch and Ferrari, 2004]. Within this context the present study focuses on the role of intermediate scales related to oceanic mesoscale eddies. Results show that a turbulent eddy field does not affect the impact of HF winds on the inertial motions. However the eddies efficiently and permanently concentrate the wind‐forced inertial motions in small‐scale anticyclonic structures. This leads to a spatially heterogeneous vertical mixing strongly related to the eddy field properties.