bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Hodograf der Bewegung eines materiellen Punktes in der relativistischen Mechanik
Authors: Zâgânescu M. 
Published: May 2007

AbstractDie Hodografengleichung wird aus den relativistischen Bewegungsgleichungen abgeleitet und zwar wird nur die zweidimensionale Bewegung betrachtet. Diese Gleichung ist vom Ricattischen Typ. Falls die Komponenten der Kraft konstant sind, stellt der Hodograf eine Äquidistante dar.
Über die Auswertung von Leitfähigkeitsglowkurven
Authors: Böer K. W. , Oberländer S. , Voigt J. 
Published: May 2007

AbstractEs wird für ein einfaches reaktionskinetisches Modell mit einer Hafttermgruppe einheitlicher energetischer Lage der Verlauf der Lösungsfunktionen des ihm entsprechenden Gleichungssystems diskutiert, unter gewissen Näherungsannahmen eine Methode zur Bestimmung physikalisch interessierender Parameter aus Leitfähigkeitsglowkurven angegeben und eine Fehlerabschätzung für die nach dieser Methode bestimmten Parameter durchgeführt. Es ergibt sich überdies, daß die Näherungsformel von Randall und Wilkins auch für Leitfähigkeitsglowkurven und auch dann, wenn ein Wiederanhaften. von Elektronen nicht vernachlässigt werden kann, recht gute Werte für den energetischen Abstand der Hafttermgruppe vom Leitungsband liefert.
Die Einstein‐Rosen‐Materie
Authors: Treder H. J. 
Published: May 2007

AbstractThe Einstein‐Rosen matter is given by a space‐time V4 in which the domains z < 0 and z > 0 are isometric. But, on the hypersurface z = 0 the Riemannian tensor Riklm and the Ricci tensor Rkl become delta‐like infinite. On this surface the first derivations of the metric tensor gik have essential discontinuities. Therefore, it is impossible to cover the small domain –ε ≤ z ≤ +ε with one coordinate system of the class C2.
Zur Interferenz unabhängiger Lichtstrahlen geringer Intensität
Authors: Radloff W. 
Published: May 2007

AbstractWe have observed the interference between two independent single mode He‐Ne laser beams. Our special equipment allowed us to record many times the interference pattern, when it was standing for a short time at the same position on the recorder. In this way we have obtained an interference picture of two independent light beams, which was (a) visible directly for the unaided eye for large intensities, (b) recorded on a photographic film for low intensities. The result of the experiments were in agreement with the statement of the quantummechanical description: We found a classical interference pattern down to very small intensities of the superposed beams. This result is discussed with regard to the quantum structure of light.
Die Beugung skalarer Wellen am elliptischen Kegel
Authors: Kirchner M. 
Published: May 2007

AbstractEs werden die Greenschen Funktionen des elliptischen Kegels in Form einer Reihenentwicklung nach geeigneten Partikulärlösungen der homogenen Wellengleichung angegeben. Das erste Glied dieser Entwicklung wird numerisch ausgewertet.
Lebensdauer und Hyperfeinstrukturaufspaltung der Terme 4d5s5p y2D3/2,5/2 und 4d5s5p y2F5/2,7/2 im Yttrium I Spektrum
Authors: Beer H. 
Published: May 2007

AbstractWith level crossing technique the states 4d5s5p y2D3/2,5/2 and 4d5s5p y2F5/2,7/2 in the Yttrium I spectrum were investigated and the magnetic hyperfine structure splitting A factors and the lifetimes determined. The experimental values are discussed and compared with theoretical results.
Innere Reibung durch Mitschleppen von Punktfehlern
Authors: Schultrich B. 
Published: May 2007

AbstractDas Mitschleppen beweglicher Punktfehler führt zu einer Dämpfung der Versetzungsbewegung. Es wird die Frequenz‐, Konzentrations‐ und Amplitudenabhängigkeit der auf diesem Relaxationsprozeß beruhenden inneren Reibung untersucht. Sie läßt sich bei kleinen Schwingungen durch einen einfachen Relaxationsprozeß mit konzentrationsabhängiger Relaxationszeit und ‐stärke beschreiben. im Falle kleiner Punktfehlerkonzentrationen. d. h. keine Hysteresedämpfung, nimmt die Höhe des Relaxationsmaximums mit wachsender Schwingungsamplitude ab und verschiebt sich zu kleineren Frequenzen.
Berechnung der Amplitudenfluktuation eines mit Laserlicht gepumpten optischen parametrischen Oszillators
Authors: Brunner W. , Paul H. 
Published: May 2007

AbstractThe intensity fluctuations of the radiation of an optical parametric oscillator have been calculated by taking into account the corresponding fluctuations of the pump light. The latter are shown to have a strong influence on the fluctuations of signal and idler waves. In contrary to the laser case, they are essentially reproduced in the signal and idler radiation; more quantitatively, the correlation function 〈ϱ(t1) ϱ(t2)〉 where ϱ denotes the deviation of the amplitude of the signal (or idler) wave from its mean value is, for t1 = t2, equal to the corresponding quantity for the pump wave apart from a reduction factor, whose value depends on the resonator losses and the relative excitation of both the pumping laser and the optical parametric oscillator and is found to be of the order of one for the normal case. It is interesting to note that for sufficiently strong pumping, the correlation function 〈ϱ(t1) ϱ(t2)〉 approaches the value zero for |t1 – t2| → ∞ not monotonically but in form of damped oscillations.
Brechzahländerungen durch Schwingungsanregung beim stimulierten Raman‐Effekt
Authors: Heumann E. , Wilhelmi B. 
Published: May 2007

AbstractDer Einfluß der stimulierten Raman‐Streuung (SRS) auf die Brechzahl infolge Schwingungsanregung von Molekülen wird für Wasserstoff und Schwefelkohlenstoff abgeschätzt. Die durch SRS hervorgerufenen Änderungen des Brechungsindex werden mit den aus Molekülorientierung und Elektrostriktion resultierenden Beiträgen verglichen. Es werden Bedingungen angegeben, unter denen derartige Brechzahländerungen und damit Polarisierbarkeiten in angeregten Zuständen beobachtbar sein müßten.
Anwendung von Doppelresonanzmethoden in der Fourier‐Transformationsspektroskopie der hochauflösenden NMR
Authors: Günther F. 
Published: May 2007

AbstractAm Beispiel eines AX‐Systems mit intramolekularer Dipol‐Dipol‐Wechselwirkung als Relaxationsmechanismus wird der Einfluß eines zweiten hochfrequenten Magnetfeldes auf die freie Induktion und deren Fourier‐Transformierte untersucht.Durch Einstrahlung des zweiten Hochfrequenzfeldes während des Abfalls der freien Induktion ergeben sich nach der Fourier‐Transformation des Signals ”︁spin‐tickling”︁ ‐bzw. Spin‐Entkopplungsspektren ohne den Einfluß des Kern‐Overhauser‐Effektes. Wird dagegen das Hochfrequenzfeld nur vor Anlegen des π/2 ‐Impulses eingestrahlt, so besteht das Fourier‐Spektrum der freien Induktion aus Linien an den Positionen des Einzelresonanz‐spektrums, deren Linienintensitäten durch den verallgemeinerten Overhauser‐Effekt verändert sind. Hierbei ergeben sich unterschiedliche Linienamplituden, je nachdem ob durch den π/2‐Impuls nur der eine Spin oder beide Spins gleichzeitig angeregt werden.
Inelastic Interaction Free Path of High Energy Neutrons with Copper Nuclei
Authors: Bhattacharyya D. P. , Das N. C. 
Published: May 2007

AbstractThe inelastic interaction free path of cosmic ray neutrons in copper was estimated by a multiplate cloud chamber operated by coincidence and anticoincidence technique of GEIGER counters and found to be 133 ± 24 g/cm2 at 37.5 ± 2.1 GeV energy. The collision free path so obtained is in agreement with the expected value calculated after the optical model of the nucleus.
Spaltbeugung von Röntgenstrahlen im Doppel‐Diffraktometer
Authors: Otto J. 
Published: May 2007

AbstractRegistrierung der Spaltbeugungsfunktion bis zum dritten Nebenmaximum für Λ=1,542 Å (Cu Kα) und a ≈ 10 μm. Λ‐Messung mit der für Spaltbeugung geringen Standardabweichung von 0,02 Å. Berechnung und experimentelle Bestätigung des Verlaufs der Winkelverbreiterung durch Spaltbeugunge für a → ∞.
The Boundary Value Problem for Helium II
Authors: Schmidt R. 
Published: May 2007

AbstractConsidering all the dissipative processes in confined helium II, it turns out that the boundary value problem, as given by the Khalatnikov equations and the already known boundary conditions has a unique solution only if one has a further condition concerning the behaviour of helium II at the boundary. In this paper such an additional boundary condition is deduced from the thermodynamics of irreversible processes. The other already known boundary conditions are also generalized, to the extent that all dissipative processes in the helium are considered. Explicit calculations will be made for the free surface case as well as for the case of a rigid immovable wall.
Exponential Transformations in Lattice Dynamics
Authors: Brühl S. , Sigmund E. , Wagner M. 
Published: May 2007

AbstractAn exponential transformation for the Hamiltonian of a perturbed harmonic lattice with arbitrary point defects is presented. It decouples one mode and leads to a derivation of the equations of the well known Lifshitz formalism in a pure quantum mechanical manner. For illustration, the method is applied to a linear chain with a single anomalous force constant.
Structural analysis of spray‐dried powders by confocal laser scanning microscopy
Authors: Soottitantawat Apinan , Peigney Julien , Uekaji Yukiko , Yoshii Hidefumi , Furuta Takeshi , Ohgawara Masaaki , Linko Pekka 
Published: May 2007

AbstractThe internal and external morphology of spray‐dried powders were investigated as a function of the operating conditions of the spray dryer by using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The blend of gum arabic (GA) and maltodextrin (MD) solution, which is normally used in the encapsulated food industry, was prepared at 30% solid content of the mass ratio of GA and MD of 1 to 3. In order to make the powder particles visible by CLSM, fluorescein sodium was used to label the solid materials. The solutions were fed through an Ohkawara L‐8 type spray dryer at different inlet air temperatures and atomizing speeds. An increase in the vacuole as well as the particle size was observed when the inlet air temperature was increased. Smaller vacuoles and lower yields of vacuoles were observed when using low atomization speeds. The density of powders decreased with an increase of the inlet air temperature as well as with an increase of the atomizing speed. Furthermore, the surface morphology presented smooth and shriveled particles for all powders, but deeper surface grooving for low inlet air temperatures. More grooves were observed by using a low atomizing speed. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Synthesis and characterization superabsorbent‐ethanol polyacrylic acid gels
Authors: Qingchun Zhao , Changling Liu 
Published: May 2007

AbstractIn this article, superabsorbent‐ethanol polyacrylic acid gels were synthesized by free‐radical aqueous polymerization method by using γ rays as initiator and varying the concentration of the Zn2+ from 0.1 to 0.3%, which acts as crosslinker. Effect of irradiation dose, monomer concentration, kind, and concentration of the crosslinker on swelling behaviors of polyacrylic acid gels were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effects of high frequency electromagnetic field (EMF) emitted by mobile phones on the human motor cortex
Authors: Inomata‐Terada Satomi , Okabe Shingo , Arai Noritoshi , Hanajima Ritsuko , Terao Yasuo , Frubayashi Toshiaki , Ugawa Yoshikazu 
Published: May 2007

AbstractWe investigated whether the pulsed high frequency electromagnetic field (EMF) emitted by a mobile phone has short term effects on the human motor cortex. We measured motor evoked potentials (MEPs) elicited by single pulse transcranial magnetic stimulation (TMS), before and after mobile phone exposure (active and sham) in 10 normal volunteers. Three sites were stimulated (motor cortex (CTX), brainstem (BST) and spinal nerve (Sp)). The short interval intracortical inhibition (SICI) of the motor cortex reflecting GABAergic interneuronal function was also studied by paired pulse TMS method. MEPs to single pulse TMS were also recorded in two patients with multiple sclerosis showing temperature dependent neurological symptoms (hot bath effect). Neither MEPs to single pulse TMS nor the SICI was affected by 30 min of EMF exposure from mobile phones or sham exposure. In two MS patients, mobile phone exposure had no effect on any parameters of MEPs even though conduction block occurred at the corticospinal tracts after taking a bath. As far as available methods are concerned, we did not detect any short‐term effects of 30 min mobile phone exposure on the human motor cortical output neurons or interneurons even though we can not exclude the possibility that we failed to detect some mild effects due to a small sample size in the present study. This is the first study of MEPs after electromagnetic exposure from a mobile phone in neurological patients. Bioelectromagnetics 28:553–561, 2007. © 2007 Wiley‐Liss, Inc.
Lack of promoting effects of chronic exposure to 1.95‐GHz W‐CDMA signals for IMT‐2000 cellular system on development of N‐ethylnitrosourea‐induced central nervous system tumors in F344 rats
Authors: Shirai Tomoyuki , Ichihara Toshio , Wake Kanako , Watanabe So‐ichi , Yamanaka Yukio , Kawabe Mayumi , Taki Masao , Fujiwara Osamu , Wang Jianqing , Takahashi Satoru , Tamano Seiko 
Published: May 2007

AbstractThe present study was performed to evaluate effects of a 2‐year exposure to an electromagnetic near‐field (EMF) equivalent to that generated by cellular phones on tumor development in the central nervous system (CNS) of rats. For this purpose, pregnant F344 rats were given a single administration of N‐ethylnitrosourea (ENU) on gestational day 18. A total of 500 pups were divided into five groups, each composed of 50 males and 50 females: Group 1, untreated controls; Group 2, ENU alone; Groups 3 to 5, ENU + EMF (sham exposure and two exposure levels). A 1.95‐GHz wide‐band code division multiple access (W‐CDMA) signal, which is a feature of the International Mobile Telecommunication 2000 (IMT‐2000) cellular system was employed for exposure of the rat head starting from 5 weeks of age, 90 min a day, 5 days a week, for 104 weeks. Brain average specific absorption rates (SARs) were designed to be .67 and 2.0 W/kg for low and high exposures, respectively. The incidence and numbers of brain tumors in female rats exposed to 1.95‐GHz W‐CDMA signals showed tendencies to increase but without statistical significance. Overall, no significant increase in incidences or numbers, either in the males or females, was detected in the EMF‐exposed groups. In addition, no clear changes in tumor types in the brain were evident. Thus, under the present experimental conditions, exposure of heads of rats to 1.95‐GHz W‐CDMA signals for IMT‐2000 for a 2‐year period was not demonstrated to accelerate or otherwise affect ENU‐initiated brain tumorigenesis. Bioelectromagnetics 28:562–572, 2007. © 2007 Wiley‐Liss, Inc.
Effects of 120 mT static magnetic field on TGF‐β1‐inhibited endothelial tubular formation in vitro
Authors: Okano Hideyuki , Tomita Naohide , Ikada Yoshito 
Published: May 2007

AbstractWe designed this study to examine the effects of static magnetic fields (SMF; 120 mT [Bmax] and a maximum spatial magnetic flux gradient of 21 mT/mm) on inhibited tubular formation when treated with human transforming growth factor (TGF)‐β1 at a relatively high concentration (5 ng/ml). Three experimental groups of 25 samples each were examined: (1) sham exposure alone (control); (2) sham‐exposure with TGF‐β1; (3) SMF exposure with TGF‐β1. The SMF or sham exposure was carried out for 10 days. Photomicrographs of tubular cells, immunostained with an anti‐platelet‐endothelial cell adhesion molecule‐1 (PECAM‐1 [CD31]) antibody as a pan‐endothelial marker, were analyzed after the 10‐day culture. SMF was found to significantly reverse the inhibition of TGF‐β1 on tubular formation in terms of the area density and length of tubules (arteriogenesis) in the peripheral part of the wells, compared with the TGF‐β1 treatment alone. These findings suggest that one of the possible exogenous factors for arteriogenesis might involve ‘magnetic force’ (the product of the magnetic flux density, the magnetic gradient, and the volume susceptibility of the cells) because values are much larger in the peripheral part than in the central part. Bioelectromagnetics 28:497–499, 2007. © 2007 Wiley‐Liss, Inc.
Pulsed electromagnetic fields affect osteoblast proliferation and differentiation in bone tissue engineering
Authors: Tsai Ming‐Tzu , Chang Walter Hong‐Shong , Chang Kyle , Hou Ru‐Jyuan , Wu Tai‐Wei 
Published: May 2007

AbstractBone tissue engineering is an interdisciplinary field involving both engineers and cell biologists, whose main purpose is to repair bone anatomical defects and maintain its functions. A novel system that integrates pulsed electromagnetic fields (PEMFs) and bioreactors was applied to bone tissue engineering for regulating osteoblast proliferation and differentiation in'vitro. Osteoblasts were acquired from the calvaria of newborn Wistar rats and isolated after sequential digestion. Poly(DL‐lactic‐co‐glycolic acid) (PLGA) scaffolds were made by the solvent merging/particulate leaching method. Osteoblasts were seeded into porous PLGA scaffolds with 85% porosity and cultured in bioreactors for the 18‐day culture period. Cells were exposed to PEMF pulsed stimulation with average (rms) amplitudes of either 0.13, 0.24, or 0.32 mT amplitude. The resulting induced electric field waveform consisted of single, narrow 300 µs quasi‐rectangular pulses with a repetition rate of 7.5'Hz. The results showed that PEMF stimulation for 2 and 8 h at .13 mT increased the cell number on days 6 and 12, followed by a decrease on day 18 using 8 h stimulation. However, ALP activity was decreased and then increased on days 12 and 18, respectively. On the other hand, PEMF‐treated groups (irrespective of the stimulation time) at 0.32 mT inhibited cell proliferation but enhanced ALP activity during the culture period. These findings suggested that PEMF stimulation with specific parameters had an effect on regulating the osteoblast proliferation and differentiation. This novel integrated system may have potential in bone tissue engineering. Bioelectromagnetics 28:519–528, 2007. © 2007 Wiley‐Liss, Inc.
Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms
Authors: Ashton H A , Gao L , Kim L G , Druce P S , Thompson S G , Scott R A P 
Published: May 2007

Abstract

Background
Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined.

Methods
One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65–80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death).

Results
In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1·8 to 1·6 per cent, hazard ratio 0·89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0·56 per 1000 person-years).

Conclusion
Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented. Registration number: ISRCTN 00079388 (http://www.controlled-trials.com).
Platelet function and antiplatelet therapy
Authors: Troxler M , Dickinson K , Homer-Vanniasinkam S 
Published: May 2007

AbstractBackgroundPlatelets have roles other than haemostasis and many are relevant to surgical practice. This review examines both the pathophysiology of platelets in haemostasis and thrombosis, and other roles of clinical importance.MethodsA literature review of the various functional roles of platelets was performed (Medline search, English language) including their action in inflammation (in particular in atherothrombosis), antimicrobial defence and tumour growth. Current clinical evidence for antiplatelet therapy is also reviewed.Results and conclusionPlatelet functions are multiple, complex and not limited to haemostasis. Understanding of platelet pathophysiology continues to grow and this is relevant to many aspects of surgical practice, particularly the clinical use of antiplatelet therapy.
Precolumn fluorescence labeling method for simultaneous determination of hydroxyzine and cetirizine in human serum
Authors: Hammad Sherin Farouk , Mabrouk Mokhtar Mohamed , Habib Ahmed , Elfatatry Hamed , Kishikawa Naoya , Nakashima Kenichiro , Kuroda Naotaka 
Published: May 2007

AbstractA highly selective and sensitive method was developed for simultaneous determination of the antihistaminic drug hydroxyzine (HZ) and its pharmacologically active metabolite cetirizine (CZ) in human serum using haloperidol as internal standard. The method was based on fluorescence labeling of both drugs with a fluorescent arylboronic acid 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenyl boronic acid followed by separation on silica column using a mobile phase consisting of acetonitrile and water (90:10, v/v%) containing triethylamine and acetic acid. The labeling reaction conditions were optimized and the liquid–liquid extraction method was successfully applied to extract the both drugs from serum. The linearity range was 0.025–2.00 µg/mL for HZ and CZ. The limit of detection (S/N = 3) was 10 and 5 ng/mL for HZ and CZ, respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Die Umesterung von Orthokieselsäureestern
Authors: Helferich Burckhardt , Reimann Wolfgang 
Published: May 2007

AbstractEs wurde gefunden, daß Orthokieselsäureester niederer Alkohole sich unter dem katalytischen Einfluß von Alkoholat‐Ionen höherer Alkohole glatt in die Ester dieser Alkohole umestern lassen.
Über eine neue Methode zur Herstellung von α‐Naphthylessigsäure
Authors: Griehl Wolfgang 
Published: May 2007

AbstractDurch Dehydrierung von Naphthalin in Gegenwart von Essig‐säureanhydrid erhält man bei Einhaltung gewisser Bedingungen dic als Pflanzenwuchs‐ bzw. hemmstoff bekannte α‐Naphthylessigsäure in guter Ausbeute. Die neue Reaktion ist nicht auf Naphthalin beschränkt, sondern man kan grundsätzlich alle aromatischen Kohlenwasserstoffe mit ähnlich beweglichem Wasserstoffatom in die entsprechenden Arylessigsäuren.
Über eine neue Synthese dialkylierter Brenztraubensäuren
Authors: Wieland Theodor 
Published: May 2007

AbstractDialkylierte Brenztraubensäuren lassen sich aus den Magnesium‐Verbindungen von sek. Halogenparaffinen und Oxalester in Ausbeuten bis zu 30% darstellen, wenn man die Grignard‐Lösung zu einem Überschuß des Esters in Äther bei gemäßigter Temperatur tropfen läßt.
Unterscheidbarkeit von Aldosen und Ketosen durch die Osazonbildungs‐Geschwindigkeit in Gegenwart von Anilin
Authors: Weygand Friedrich , Reckhaus Margaret 
Published: May 2007

AbstractDie Osazonbildungs‐Geschwindigkeit aus Aldopentosen bzw. Aldohexosen und Phenylhydrazin in verdünnter Essigsäure wird durch Anilinzusatz erheblich gesteigert. Ketosen zeigen dieses Verhalten nicht.
Über Indoxylrot
Authors: Seidel Paul 
Published: May 2007

AbstractEs werden die bei der Umsetzung des Indoxylrots mit Oxindol, Hydrogensulfit, Alkali, Permanganat und Salpetriger Säure entstehenden Reaktionsprodukte sowie ein bei seiner Dimerisation in Pyridin gebildetes Nebenprodukt beschrieben und Konstitutions formeln für die erhaltenen Verbindungen abgeleitet.
Zur Umkehrbarkeit metallorganischer Additionsreaktionen
Authors: Wittig Georg , Nagel Konrad 
Published: May 2007

AbstractAn zwei Beispielen wird gezeigt, daß gewisse metallorganische Additionen nicht möglich sind, da die auf Umwegen hergestellten Addukte im Augenblick ihrer Bildung in ihre Komponenten zerfallen.