bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur Thermodynamik von Systemen mit zwei Temperaturen
Authors: Ziemann H.
Published: May 2007

Der erste und zweite Hauptsatz der Thermodynamik werden auf Systeme verallgemeinert, deren stabile Zustände durch zwei Temperaturen gekennzeichnet sind. Die Abgrenzung solcher Systeme gegenüber denen der konventionellen Art erfolgt durch die Forderung, daß sie durch äußere Parameter und zwei zusätzliche Variable beschrieben werden können. Ihre Wechselwirkungen miteinander haben die in der herkömmlichen Theorie zugrunde gelegte Struktur. Diese Wechselwirkungen definieren im Verein mit der genannten Voraussetzung über Anzahl und Art der zur Beschreibung notwendigen Parameter zwei Temperaturen und zwei innere Energien. Ferner gestattet der eine von zwei möglichen Systemtypen die Konstruktion einer Entropie. An dieser Stelle wird nur dieser Typ behandelt.
Zur statistischen Thermodynamik von Teilchensystemen mit kurz‐ und weitreichenden Wechselwirkungen
Authors: Schmitz G.
Published: May 2007

Auf der Grundlage der BBGKY‐Hierarchie werden für klassische Systeme von Teilchen unter Berücksichtigung von kurz‐ und weitreichenden Wechselwirkungen die molekularen Verteilungsfunktionen berechnet. Die Hierarchie wird durch eine konvergente uneigentliche Dichteentwicklung gelöst. Die freie Exzeßenergie wird über einen Aufladungsprozeß bis zum vierten Koeffizienten in der Entwicklung angegeben.
Über anomale GREENsche Funktionen für flüssiges Helium 4
Authors: Fritzsch K.
Published: May 2007

In kondensierten Systemen vieler Teilchen sind anomale GREENsche Funktionen, so z. B. die aus drei Erzeugungs‐ bzw. Vernichtungsoperatoren bestehende Dreihalbe‐Funktion zu beachten. Aussagen über Dreihalbe‐Funktionen mit äußeren Phononlinien, die bisher mit phänomenologischen Argumenten geltend gemacht worden sind, werden mikroskopisch begründet. In den Selbstenergieteilen führen die anomalen Beiträge zu Singularitäten, die sämtlich behoben werden können. Im Zerfallsbereich gelingt dies durch Annahme einer komplexen Anregungsenergie.
Zur Diskontinuität der Impulsverteilung im Grundzustand eines dichten Elektronengases
Authors: Ziesche P.
Published: May 2007

The density dependence of the discontinuity in the one‐particle momentum distribution of an electron gas in the high density limit ground state is calculated.
Anlaufvorgang der Molekularströmung in Rohren mit Teilchenadsorption bei nichtlinearer Adsorptionsisotherme
Authors: Teubner W. , Paul G.
Published: May 2007

Der Anlaufvorgang der molekularen Strömung von Gasen durch Rohre wird als Diffusionsproblem behandelt und die Verzögerungszeit bis zur Einstellung stationärer Verhältnisse bei physikalischer Adsorption von Teilchen für verschiedene Adsorptionsisothermen berechnet. Dazu dient eine Methode von Frisch, nach der sich die Verzögerungszeit unter Umgehung einer Lösung der im allgemeinen nichtlinearen Differentialgleichung aus den Daten der stationären Strömung ermitteln läßt. Das Verfahren wird für die Adsorptionsisothermen nach Langmuir sowie nach Dubinin und Raduškevič angewendet, wobei Aussagen über die Genauigkeit einer von Clausing angegebenen einfachen Näherungsformel für die Verzögerungszeit möglich sind. In Umkehrung der Problemstellung wird gezeigt, wie sich aus Ergebnissen von Strömungsexperimenten Adsorptionsisothermen gewinnen lassen.
Vereinfachung der Störungstheorie von Atomen und Molekülen durch Verwendung separabler Potentiale
Authors: Hausmann K.
Published: May 2007

Es wird aus den im Grundzustand besetzten Hartree‐Fock‐Einelektronenwellen‐funktionen ein einfacher Modellhamiltonoperator konstruiert. Dieser Einelektronenoperator enthält außer der kinetischen Energie eine Überlagerung von Projektionsoperatoren. Er besitzt als gebundene Zustände nur die besetzten Hartree‐Fock‐Zustände. Die Berechnung der unbesetzten Zustände und damit der Störungsterme ist wesentlich einfacher als beim Hartree‐Fock‐Operator. Für das Heliumatom konvergiert die zum Modelloperator gehörende Störungsreihe fast ebenso rasch wie die Störungstheorie ausgehend vom Hartree‐Fock‐Operator.
Influence of Electronic Shell on Gamma Radiation of Atomic Nuclei
Authors: Krutov V. A. , Fomenko V. N.
Published: May 2007

Additional de‐excitation of the nucleus over the electronic shell is considered, the excited states of the electronic shell being intermediate in such de‐excitation.
Einschwingvorgänge der magnetischen Resonanz und subharmonische Resonanzen beim optischen Pumpen an 201Hg
Authors: Cappeller U. , Dellit L.
Published: May 2007

The dynamical equations for optical pumping are studied in the case of the alignment of 201Hg. The transients of the magnetic resonance in the ground state (I = 3/2) and subharmonic resonances in a linearly polarized H1‐field are observed.
Comparison of colour development in sugar–amino acid solutions with colour changes in wood during drying
Authors: McCurdy Murray C. , Pang Shusheng
Published: May 2007

Kiln brown stain (KBS) is a major concern in the drying of high‐grade softwood due to the darkened wood surface. Although numerous studies have been conducted in the last decade, the mechanism of the KBS formation is still not fully understood. One theory is that the KBS is caused by Maillard reaction between the concentrated sap solution and the surrounding drying medium during drying. The present study has investigated this theory using artificial sap solution at various concentrations. Colour development of these solutions treated at different temperatures is measured and compared with the actual colour changes in Pinus radiata sapwood during drying. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Competitive hydrogen bonding mechanisms underlying phase behavior of triple poly(N‐vinyl pyrrolidone)–poly(ethylene glycol)–poly(methacrylic acid‐co‐ethylacrylate) blends
Authors: Kireeva Polina E. , Shandryuk Georgy A. , Kostina Julia V. , Bondarenko Galina N. , Singh Parminder , Cleary Gary W. , Feldstein Mikhail M.
Published: May 2007

Differential scanning calorimetry (DSC) of triple blends of high molecular weight poly(N‐vinyl pyrrolidone) (PVP) with oligomeric poly(ethylene glycol) (PEG) of molecular weight 400 g/mol and copolymer of methacrylic acid with ethylacrylate (PMAA‐co‐EA) demonstrates partial miscibility of polymer components, which is due to formation of interpolymer hydrogen bonds (reversible crosslinking). Because both PVP and PMAA‐co‐EA are amorphous polymers and PEG exhibits crystalline phase, the DSC examination is informative on the phase state of PEG in the triple blends and reveals a strong competition between PEG and PMAA‐co‐EA for interaction with PVP. The hydrogen bonding in the triple PVP–PEG–PMAA‐co‐EA blends has been established with FTIR Spectroscopy. To evaluate the relative strengths of hydrogen bonded complexes in PVP–PEG–PMAA‐co‐EA blends, quantum‐chemical calculations were performed. According to this analysis, the energy of H‐bonding has been found to diminish in the order: PVP–PMAA‐co‐EA–PEG(OH) > PVP–(OH)PEG(OH)–PVP > PVP–H2O > PVP–PEG(OH) > PMAA‐co‐EA–PEG(O) > PVP–PMAA‐co‐EA > PMAA‐co‐EA–PEG(OH). Thus, most stable complexes are the triple PVP–PMAA‐co‐EA–PEG(OH) complex and the complex wherein comparatively short PEG chains form simultaneously two hydrogen bonds to PVP carbonyl groups through both terminal OH‐groups, acting as H‐bonding crosslinks between longer PVP backbones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Designing acrylamide‐ and methacrylate‐based novel supports for lipase immobilization
Authors: Chauhan Ghanshyam S. , Chauhan Sandeep , Kumar Yogesh , Thakur Usha Sen , Kanwar S. S. , Kaushal Rajeev
Published: May 2007

To design efficient polymeric supports for lipase immobilization, two series of hydrogels based on acrylamide and three methacrylates were prepared via crosslinking with ethylene glycol methacrylate and N,N‐methylenebisacrylamide. The three methacrylates used to prepare these hydrogels had different alkyl chain lengths: C1 (methyl methacrylate), C12 (dodecyl methacrylate), and C18 (octadecyl methacrylate). In the reaction scheme, only the feed concentration of the hydrophobic component (methacrylate) was varied. The characterization of the hydrogels was carried out with Fourier transform infrared, scanning electron microscopy, and nitrogen analysis to establish their structural aspects and to obtain evidence for network formation; the swelling and water uptake of the hydrogels were studied as functions of the time, temperature, and pH. Lipase immobilization on selected hydrogels was studied as a function of the concentration of the methacrylate used in the feed and the nature of the crosslinker. The activity of the hydrogel series that showed the highest activity of the immobilized lipase was investigated further as a function of the methacrylate feed concentration, pH, and temperature. Some organic solvents were studied to investigate the effect of the nature of the solvent on the activity of the immobilized lipase. The activity of the immobilized lipase was more than that of the free lipase and was affected by the structural attributes of the polymeric supports and by the nature of the solvent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Properties of films from corn zein reacted with glutaraldehyde
Authors: Sessa David J. , Mohamed Abdellatif , Byars Jeffrey A. , Hamaker Sharon A. H. , Selling Gordon W.
Published: May 2007

To improve the mechanical properties of zein films, a commercial white zein was reacted in glacial acetic acid (HAc) with glutaraldehyde (GDA) from 0.5 to 16% by weight based on the weight of zein. Amounts of 4% or higher GDA‐modified zein, when cured in a closed system, generated a gel. That gel was insoluble in organic solvents known to solubilize zein. Zein solutions cast within a silicon rubber gasket sealed onto Teflon‐coated plates, when air dried, generated 0.7–0.9‐mm thick films. Those films from 8% GDA‐modified zein had a water vapor permeability of 5.9 × 10−8 g cm/Pa s m2. Overall, results indicate that our thicker films gave higher water vapor permeability than values reported in the literature. To achieve consistent and comparable results with differential scanning calorimetry (DSC) and dynamic mechanical analyses (DMA), film samples had to be heated to remove residual HAc. An increase in the glass transition temperatures for those films from GDA‐modification of zein, observed with both DSC and DMA, was attributed to the crosslinking of zein. Physical testing of tensile bars cut from GDA‐modified zein films showed minor enhancement of tensile strength, percent elongation, and Young's modulus in the 0.5% GDA‐modified zein films, which increased and leveled off with 4% or higher amounts of GDA for the modifications. When the 4 to 16% GDA results are averaged, the tensile strength for the modified zein films increased 1.8‐fold when compared with unmodified zein control films. On the same note, percent elongation showed a 1.8‐fold increase and Young's modulus showed a 1.5‐fold increase. GDA reaction with zein generated films with improved tensile strength, ductility, and stiffness when compared with respective zein control films that retained their integrity when subjected to either boiling water or extensive soaking. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Electrical properties of segregated ultrahigh molecular weight polyethylene/multiwalled carbon nanotube composites
Authors: Xi Ying , Yamanaka Atsuko , Bin Yuezhen , Matsuo Masaru
Published: May 2007

Multiwalled carbon nanotubes (MWNTs) and ultrahigh molecular weight polyethylene (UHMWPE) composites are prepared using paraffin as solvent. The resulting electrical properties show lower electrical percolation threshold, which is 1.4 vol %, than that of UHMWPE‐MWNT composites prepared by gelation/crystallization from decalin solution. Good reproducibility and higher maximum of electrical conductivity are obtained. The extremely low electrical percolation threshold indicates that the dispersion of MWNTs is segregated, which can be proved by the morphology of the film observed by optical microscopy. The complex planes of electric modulus are useful to analyze the dispersion of MWNTs and the quality of interparticle contacts. In addition, the result of thermogravimetry shows that the retardation of onset of UHMWPE decomposition in inert gas is observed in the mixture with MWNTs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Superabsorbent hydrogel based on modified polysaccharide for removal of Pb2+ and Cu2+ from water with excellent performance
Authors: Guilherme Marcos R. , Reis Adriano V. , Paulino Alexandre T. , Fajardo André R. , Muniz Edvani C. , Tambourgi Elias B.
Published: May 2007

This contribution describes the absorption percentage of Pb2+ and Cu2+ from water by a superabsorbent hydrogel matrix (SH) made from an anionic polysaccharide copolymerized with acrylic acid (AAc) and acrylamide (AAm). Metal‐absorption tests, upon sequential pH variation, indicated that the SH has pH‐sensitivity for the absorption of both metals from solution, attributed to the functional ionic groups (COOH) present in the AAc and arabic gum (AG) segments. At the pH 5.0, the SH exhibited good absorption capacity: 73.10% for Pb2+, 81.99% for Cu2+ in water and 63.64% for Pb2+, and 76.67% for Cu2+ in saline water with 0.1 mol kg−1 ionic strength. A replicated 22 full factorial design with a central point was built to evaluate the maximum absorption capacity of the metals into the SH. It was found that both the interaction and main effects of the pH and the initial concentration of metal solution on absorption percentage of the metals were statistically significant. Surface response plots indicated that the absorption capacity of both metals into the SH may be appreciably improved by using the solutions with lower initial concentration of metal and with higher pH values. Metal‐absorption results demonstrated that the SH is a convenient material for absorption of Pb2+ and Cu2+ from pure aqueous and saline aqueous environments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Behavior of α‐ and β‐cyclodextrin‐encapsulated allyl isothiocyanate as slow‐release additives in polylactide‐co‐polycaprolactone films
Authors: Plackett David , Ghanbari‐Siahkali Afshin , Szente Lajos
Published: May 2007

The natural antibacterial agent allyl isothiocyanate (AITC) encapsulated in either α‐ or β‐cyclodextrin (CD) has previously been evaluated as a slow‐release additive in polylactide‐co‐polycaprolactone (PLA–PCL) films designed for use in cheese packaging. In the research described in this article, thermogravimetric analysis (TGA) and thermogravimetric analysis in tandem with mass spectrometry (TGA–MS) were used to explore the thermal properties of CD‐encapsulated AITC complexes as well as those of PLA–PCL films containing these complexes. To our knowledge, this is the first reported application of the TGA–MS technique to explore the thermal stability of CD‐entrapped AITC and the first study to report differences in thermal stability of AITC in α‐and β‐CD cavities in the solid state. Observed differences in the thermal degradation profile of films containing the CD complexes can be explained if AITC binds more strongly to β‐CD than to α‐CD. This hypothesis has been reinforced by gas chromatography (GC) and high performance liquid chromatography (HPLC) studies, the results of which suggest that a new covalently bound AITC–CD complex may be formed when incorporating the β‐CD complex of AITC in PLA–PCL films but not when incorporating the α‐CD complex of AITC. This finding means that the α‐CD complex of AITC would be preferred in situations where adequate long‐term controlled release of AITC from polymer films is required, as for example in the case of active packaging applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Alternating‐current impedance and chronoamperometry studies of poly(vinylidene fluoride‐co‐hexafluoropropylene)–polyacrylonitrile‐based microporous polymer blend electrolytes prepared by a phase‐inversion technique
Authors: Sundaram N. T. Kalyana , Vasudevan T. , Subramania A.
Published: May 2007

This article describes a comparative study of poly(vinylidene fluoride‐co‐hexafluoropropylene)–polyacrylonitrile‐based plain gel polymer blend electrolytes and microporous gel polymer blend electrolytes. Scanning electron microscopy, differential scanning calorimetry, alternating‐current impedance, chronoamperometry, and dielectric spectroscopy studies were carried out. The microporous gel polymer blend electrolytes enhanced the ionic conductivity, lithium transference number, and dielectric permittivity, and this could be attributed to a higher uptake of the electrolyte solution (an increase in the number of charge carriers) by the porous structure. The temperature dependence of the ionic conductivity of the polymer electrolyte followed an Arrhenius relationship. An LSV experiment was carried out to investigate the electrochemical stability in the polymer electrolyte. Finally, charge–discharge studies of lithium‐ion cells made from the coupling of gel polymer blend electrolytes (plain and microporous) with LiMg0.10Mn1.90O4 as a cathode and carbon as an anode were conducted. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of poly(methyl methacrylate) nanocomposites with superior impact strength
Authors: Singh Dhananjay , Jayasimha T. , Rai K. N. , Kumar Anil
Published: May 2007

A chemically stable syrup of poly(methyl methacrylate) in its monomer was prepared with a suitable dual‐initiating system. Nanoalumina particles were prepared by the autoignition of aluminum nitrate with urea and were made compatible with the organic medium by chemical modification with methacrylol isocyanate. The polymer syrup prepared in this way was applied between two poly(methyl methacrylate) sheets (each 10 cm × 10 cm × 2 mm), and the composite thus prepared was tested with a bullet‐firing machine and a drop‐weight‐impact testing machine. The impact strength measurements of the two‐plate composite from both of these procedures showed that the impact resistance doubled in the case of nanoalumina. The modeling of the damage to the multilayered composite by the critical impact energy was performed with the relation E = pn2 + qn + r, where E is the impact energy, p, q, and r are constants, and n is the number of layers. Experiments showed that the presence of nanoparticles in the adhesive increased the value of the constants. The 10‐layer composite was further tested with a 0.32 Indian Ordinance Factory (IOF) revolver with a bullet mass of 9.9 g and a muzzle velocity of 236 ± 7 m/s (muzzle energy = 275 J) from a 10‐m distance, which produced an ordinary indentation with no penetration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Betweenness centrality as an indicator of the interdisciplinarity of scientific journals
Authors: Leydesdorff Loet
Published: May 2007

In addition to science citation indicators of journals like impact and immediacy, social network analysis provides a set of centrality measures like degree, betweenness, and closeness centrality. These measures are first analyzed for the entire set of 7,379 journals included in the Journal Citation Reports of the Science Citation Index and the Social Sciences Citation Index 2004 (Thomson ISI, Philadelphia, PA), and then also in relation to local citation environments that can be considered as proxies of specialties and disciplines. Betweenness centrality is shown to be an indicator of the interdisciplinarity of journals, but only in local citation environments and after normalization; otherwise, the influence of degree centrality (size) overshadows the betweenness‐centrality measure. The indicator is applied to a variety of citation environments, including policy‐relevant ones like biotechnology and nanotechnology. The values of the indicator remain sensitive to the delineations of the set because of the indicator's local character. Maps showing interdisciplinarity of journals in terms of betweenness centrality can be drawn using information about journal citation environments, which is available online.
Can citation analysis of Web publications better detect research fronts?
Authors: Zhao Dangzhi , Strotmann Andreas
Published: May 2007

We present evidence that in some research fields, research published in journals and reported on the Web may collectively represent different evolutionary stages of the field, with journals lagging a few years behind the Web on average, and that a “two‐tier” scholarly communication system may therefore be evolving. We conclude that in such fields, (a) for detecting current research fronts, author co‐citation analyses (ACA) using articles published on the Web as a data source can outperform traditional ACAs using articles published in journals as data, and that (b) as a result, it is important to use multiple data sources in citation analysis studies of scholarly communication for a complete picture of communication patterns. Our evidence stems from comparing the respective intellectual structures of the XML research field, a subfield of computer science, as revealed from three sets of ACA covering two time periods: (a) from the field's beginnings in 1996 to 2001, and (b) from 2001 to 2006. For the first time period, we analyze research articles both from journals as indexed by theScience Citation Index(SCI) and from the Web as indexed byCiteSeer. We follow up by an ACA ofSCIdata for the second time period. We find that most trends in the evolution of this field from the first to the second time period that we find when comparing ACA results from theSCIbetween the two time periods already were apparent in the ACA results fromCiteSeerduring the first time period.
Ir A.H. de Voogt: life and career of a radio pioneer
Authors: Strom R.G.
Published: May 2007

There are probably few radio astronomers who would be able to recall A.H. de Voogt, which is unfortunate, but at the same time unsurprising: for he published no original astronomical research, never carried out pioneering observations, nor is his name linked to either theoretical or instrumental breakthroughs. Yet he was described by the man who first observed the 21 cm hydrogen line from the Netherlands as a radio astronomy pioneer, at the very birth of the Dutch effort. He was, moreover, a trail blazer at the cutting edge of radio, not once but twice in his career. Without him it is unlikely that the 21 cm line would have been observed in the Netherlands in 1951, and arguably the H I mapping of the Milky Way under Jan Oort's leadership would have taken place much later, if at all. Radio astronomy observing itself might well have been compromised by interference had it not been for De Voogt's foresight.

Anthonet Hugo de Voogt (1892–1969) built, while still a teenager, one of the very first amateur radio stations (call letters VO: · · · –/– – –) in Holland, earned the radio‐telegrapher's diploma during his student days, and was intimately involved in the foundation of the Dutch Society for Radio‐Telegraphy in 1916. Until the 1920s, he was very active in amateur radio and astronomy circles. Trained in electrical engineering at Delft, he joined the PTT (Post Office) as a telegraph engineer in 1919, worked his way through the ranks to become head of the telephone district of Breda in 1939, and was promoted to head the PTT Radio Service just days after the end of the war. As his department was responsible for overseas radio communication, he initiated a research effort to study radio propagation in the ionosphere and the effects of solar activity. To this end, he rescued a number of Würzburg‐Riese 7.5‐m radar antennas abandoned at the end of the war, made one available for Jan Oort's H I work, and launched a series of radio astronomical initiatives. His group also built a number of antennas, monitored solar emission, and participated in the International Geophysical Year (1957–1958). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The search for the elusive Zeeman effect in HI
Authors: Davies R.D.
Published: May 2007

The paper describes the early endeavours by radioastronomers to detect the weak signature of the Zeeman effect in interstellar neutral hydrogen clouds in an effort to measure the Galactic magnetic field strength. The search is set in the context of the neutral hydrogen programme at Jodrell Bank. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Early Cambridge radio astronomy
Authors: Smith F.G.
Published: May 2007

Radio astronomy started in Cambridge immediately after the hostilities of the World War II have ceased. Martin Ryle was the inspiring leader of a small group that started to develop interferometry techniques at the Cavendish Laboratory. From this development came the numerous Cambridge radio source surveys culminating in the Nobel prize awarded to Martin Ryle for invention of aperture synthesis. The history of this early development is the subject of the present paper. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The beginnings of decameter radio astronomy: pioneering works of Semen Ya. Braude and his followers in Ukraine
Authors: Vavilova I.B. , Konovalenko A.A. , Megn A.V.
Published: May 2007

S.Ya. Braude (1911–2003) was the well‐known radio astronomer, one of the founders of low‐frequency astronomical research in the world, in particular in the former Soviet Union. He began to work in this field of science in 1957, in Kharkiv city (Ukraine), from the design and manufacturing small decameter interferometer ID‐1 and ID‐2. Since that time Braude and his team have developed more sophisticated radio decameter telescopes as UTR‐1 and UTR‐2 (the largest in the world till now) as well as the first decameter VLBI network URAN. They have obtained some important pioneering results about low‐frequency radio emission of objects in our Solar system, Galaxy and Metagalaxy by means of these telescopes. In this paper the key events of early history of decameter radio astronomy research in the former USSR are mentioned with emphasizing the role of S. Braude. For the period of 1957–1962, the quotations of Braude's Personal Diary (2003) are first laying open to the public. The most important results obtained by S.Ya. Braude and his followers as well as perspectives of decameter radio astronomy in Ukraine and in the world are highlighted briefly. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Early VLBI in the USSR
Authors: Matveenko L.I.
Published: May 2007

This article gives story of interferometer with independent elements (Very Long Baseline Interferometer) in Russia. At the end of February 1962 the author discussed with G.Ya. Gus'kov, DSN Station, Evpatorija a new type of radio interferometer and proposed an experiment between two DSN stations. In September 1962 he reported the new method and proposed a VLBI experiment at seminar of Radio Astronomical Laboratory, Pushino, and then at a seminar of Astronomical Institute GAISH which recommended to take out a Patent. In December GAISH sent documents to the Patent Bureau. In summer 1963 the author discussed with B. Lovell in Evpatorija the VLBI method of and we signed memorandum an Ev‐JB experiment at λ = 32 cm. In December 1963 the Patent Bureau permitted publication, and the paper was sent to Radiofizika. Really VLBI in the USSR began with the proposal of M. Cohen and K. Kellermann, February 1968, to do an experiment between 22‐m antenna Pushino and 43‐m Green Bank. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fifty years of the Stockert Radio Telescope and what came afterwards
Authors: Wielebinski R.
Published: May 2007

The Stockert radio telescope was inaugurated 50 years ago. It is the beginning of German radio astronomy after the World War II. The 25‐m dish was for a short time the largest radio telescope in the world. It certainly was the most precise radio telescope for many years. The Bonn University Observatory was the starting base for the future Max‐Planck‐Institut für Radioastronomie with its 100‐m Effelsberg radio telescope. The early years of German radio astronomy and what came afterwards is the subject of this contribution. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dwingeloo – the golden radio telescope
Authors: van Woerden H. , Strom R.G.
Published: May 2007

The Dwingeloo 25‐m telesope, inaugurated in 1956, has played a major role in research for half a century. We trace its history back to its conception in 1944, and summarize its main achievements. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oral vaccines: new needs, new possibilities
Authors: Aziz Mohd Azhar , Midha Shuchi , Waheed Syed Mohsin , Bhatnagar Rakesh
Published: May 2007

Vaccination is an important tool for handling healthcare programs both in developed and developing countries. The current global scenario calls for a more‐efficacious, acceptable, cost‐effective and reliable method of immunization for many fatal diseases. It is hoped that the adoption of oral vaccines will help to provide an effective vaccination strategy, especially in developing countries. Mucosal immunity generated by oral vaccines can serve as a strong first line of defense against most of the pathogens infecting through the mucosal lining. Advances in elucidating the mechanism of action of oral vaccines will facilitate the design of more effective, new generation vaccines. There are promising developments in the use of different agents to effectively deliver the vaccine candidate. It is hoped that ongoing research may be able to set another cardinal point, after polio vaccine, in eradicating infectious diseases. BioEssays 29:591–604, 2007. © 2007 Wiley Periodicals, Inc.
Dynamic mutations as digital genetic modulators of brain development, function and dysfunction
Authors: Nithianantharajah Jess , Hannan Anthony J.
Published: May 2007

A substantial portion of the human genome has been found to consist of simple sequence repeats, including microsatellites and minisatellites. Microsatellites, tandem repeats of 1–6 nucleotides, form the template for dynamic mutations, which involve heritable changes in the lengths of repeat sequences. In recent years, a large number of human disorders have been found to be caused by dynamic mutations, the most common of which are trinucleotide repeat expansion diseases. Dynamic mutations are common to numerous nervous system disorders, including Huntington's disease, various spinocerebellar ataxias, fragile X syndrome, fragile X tremor/ataxia syndrome, Friedreich ataxia and other neurodegenerative disorders. The involvement of dynamic mutations in brain disorders will be reviewed, with a focus on the large group caused by CAG/glutamine repeat expansions. We will also outline a proposed role of tandem repeat polymorphisms (TRPs), with unique ‘digital’ genetic distributions, in modulating brain development and normal function, so as to generate additional mutational diversity upon which natural selection may act. BioEssays 29:525–535, 2007. © 2007 Wiley Periodicals, Inc.
Early mouse embryo development: could epigenetics influence cell fate determination?
Authors: Henckel Amandine , Tóth Szabolcs , Arnaud Philippe
Published: May 2007

It is generally assumed that the developmental program of embryogenesis relies on epigenetic mechanisms. However, a mechanistic link between epigenetic marks and cell fate decisions had not been established so far. In a recent article, Torres‐Padilla and colleagues1 show that epigenetic information and, more precisely, histone arginine methylation mediated by CARM1 could contribute to cell fate decisions in the mouse 4‐cell‐stage embryo. It provides the first indications that global epigenetic information influences allocation of pluripotent cells toward the first cell lineages. BioEssays 29:520–524, 2007. © 2007 Wiley Periodicals, Inc.
Increased serum lipid peroxides initiate atherogenesis
Authors: Yagi Kunio
Published: May 2007

The development of a reliable and relatively simple micro‐assay for lipid peroxides in serum or plasma has made it possible to conduct clinical surveys of lipid peroxide levels in man. From many studies made in Japan, those suggesting a relationship between the elevation of lipid peroxide level plasma serum and the occurrence of vascular disorders are discussed here.

The data described in this paper show that the elevation of the serum lipid peroxide level over the normal value is a direct cause of the initiation of atherogenesis. Therefore, any factor bringing about the elevation of serum lipid peroxide levels, such as irradiation, would be an indirect cause of atherogenesis. In fact, irradiation is known to provoke this disorder and to elevate serum lipid peroxide levels.
Seasonal Variation of the Chemical Constituents of the Essential Oil of Santolina etrusca from Italy
Authors: Flamini Guido , Cioni Pier Luigi
Published: May 2007

The seasonal variation of the essential oil, in terms of both yield and composition, of a population of Santolina etrusca (Asteraceae) is reported in detail for different aerial parts, including sterile branches, fertile branches, and capitula. The yields generally increased from November to June, and then decreased in August and September. The main constituents of the sterile branches were 1,8‐cineole and viridiflorol. The oil from fertile branches was characterized by myrcene as principal compound, whereas the essential oil obtained from the capitula contained germacrene D as the main constituent. Several compounds, as identified by GC and GC/MS, were found to prevail during the cold season.
Possible Molecular Evolution of Biomembranes: from Single‐Chain to Double‐Chain Lipids
Authors: Gotoh Mari , Sugawara Ayae , Akiyoshi Kazunari , Matsumoto Isamu , Ourisson Guy , Nakatani Yoichi
Published: May 2007

We have studied a possible evolution process permitting a ‘primitive’ membrane to evolve towards a membrane structure with an outer wall, similar to that of bacteria. We have investigated whether a polysaccharide bearing hydrophobic phytyl or cholesteryl chains coats giant vesicles made of single‐ or double‐chain lipids. Phytyl‐pullulan 5b was found to bind to the surface of vesicles made of either single‐ or double‐chain lipids. In contrast, cholesteryl‐pullulan 5a only coated the surface of vesicles made of double‐chain lipids. These results indicate that there must be a close match between the size and shape of membrane constituents and the hydrophobic molecules to be inserted. This process could, thus, provide a selection mechanism of lipid‐membrane constituents during the course of biomembrane evolution.

The presence of the above ‘hydrophobized’ polysaccharides on the surface of different giant vesicles was identified by lectin binding. Both concanavalin A and annexin V were shown by fluorescence microscopy to bind spontaneously to vesicles made of double‐chain lipids. Our experiments exemplify that self‐organization of amphiphiles into closed vesicles in aqueous solution automatically leads to the coating of vesicles by ‘hydrophobized’ polysaccharides, which then permit lectin binding. This is a possible mechanism for the evolution of primitive membranes towards ‘proto‐cells’.
Distribution of Phenolic Compounds in Middleeuropean Taxa of the Achillea millefolium L. Aggregate
Authors: Benedek Birgit , Gjoncaj Noela , Saukel Johannes , Kopp Brigitte
Published: May 2007

Achillea millefolium L. s.l. is a cytogenetically, morphologically, and chemically polymorphic aggregate. Besides the sesquiterpenes that possess chemotaxonomic relevance and mediate the antiphlogistic activity, the plant contains phenolic compounds such as dicaffeoylquinic acids and flavonoids causing choleretic and spasmolytic effects. To evaluate their contribution to the chemotaxonomy of European taxa of the A. millefolium group, we developed a SPE‐HPLC/UV method that allows quantification of the phenolic constituents in the different taxa. The investigated species displayed differences in the quantitative and qualitative composition of phenolic acids and flavonoids. Hence, they seem to be of chemotaxonomic significance, especially for the distinction of the diploid taxa. Combining the obtained results with the data of the sesquiterpene analyses gives a comprehensive insight into the distribution of those pharmacologically relevant plant constituents in the A. millefolium group.
Starch Degradation by Glucoamylase Glm from Saccharomycopsis fibuligera IFO 0111 in the Presence and Absence of a Commercial Pullulanase
Authors: Valachová Katarína , Horváthová Viera
Published: May 2007

This study describes the course of enzymatic hydrolysis of the native corn starches Maritena 100 and Maritena 300. Hydrolyses were carried out with glucoamylase Glm produced by Saccharomycopsis fibuligera IFO 0111, which degrades also native starch, with the purpose to substitute a two‐step hydrolysis (amylase followed by glucoamylase) by a one‐step process (glucoamylase only). Hydrolysis generally became more effective by adding the pullulanase Promozyme D, which cleaves α‐1,6‐glycosidic bonds more effectively than glucoamylase Glm does. The time course (kinetics) of hydrolysis was followed by determination of the glucose concentration and calculation of dextrose equivalents.
Cytotoxic and Apoptosis‐Inducing Properties of Auriculoside A in Tumor Cells
Authors: Zhang Rusong , Liu Yulan , Wang Yiqi , Ye Yiping , Li Xiaoyu
Published: May 2007

The C21‐steroidal glycoside auriculoside A (1), recently isolated from the roots of Cynanchum auriculatum, was found to inhibit the growth of several human tumor cell lines and to induce apoptosis in human breast cancer (MCF‐7) cells. Compound 1 was evaluated for its in vitro cytotoxicity against MCF‐7, HO‐8910, and Bel‐7402 cells, and for its in vivo antitumor effects on implanted sarcoma‐180 (S180) tumors in mice. It showed significant, concentration‐dependent inhibition of the cancer cells, both in vitro and in vivo. MCF‐7 Cells exposed to 1 displayed typical morphological apoptosis characteristics such as cytoplasm contraction and nuclear‐chromatin condensation. Flow‐cytometric analysis showed that the MCF‐7 cell cycle was arrested at the G0/G1 phase. When treated with 40 μg/ml of 1 for 24, 48, and 72 h, respectively, the apoptotic rates of the cells were ca. 5, 8, and 18.5%, respectively.
Rhizobialide: A New Stearolactone Produced by Mesorhizobium sp. CCNWGX022, a Rhizobial Endophyte from Glycyrrhiza uralensis
Authors: Wei Ge‐Hong , Yang Xue‐Ying , Zhang Ji‐Wen , Gao Jin‐Ming , Ma Yong‐Qing , Fu Yun‐Yun , Wang Pang
Published: May 2007

The endophytic strain Mesorhizobium sp. CCNWGX022 was isolated from licorice (Glycyrrhiza uralensis Fisch.) grown in the arid and semi‐arid regions of Northwest China. The new stearic acid derived γ‐lactone 1, named rhizobialide (=(5S)‐4,5‐dihydro‐5‐(8‐oxotetradecyl)furan‐2(3H)‐one), was isolated from the petroleum‐ether extract of the fermentation broth of this strain. The structure of 1 was elucidated on the basis of spectroscopic and mass‐spectrometric analysis. This is the first report of this type of compound from rhizobia.
Secondary Metabolites from Endophytic Streptomyces sp. Lz531
Authors: Zhao Pei‐Ji , Wang Hao‐Xin , Li Guo‐Hong , Li Hua‐Dong , Liu Jin , Shen Yue‐Mao
Published: May 2007

From the branch tissue of Maytenus hookeri, the endophytic strain Lz531 was isolated, and determined to belong to Streptomyces, according to its 16S rRNA sequence. From the extracts of the fermentation broth of Streptomyces sp. Lz531, two new and four known compounds were isolated. The two new compounds were identified as cyclo(L‐Pro‐L‐Val‐L‐Val) (1) and 13‐methyl‐N‐(2‐phenylethyl)tetradecanamide (2).
Variability of the Needle Essential Oils of Pinus heldreichii from Different Populations in Montenegro and Serbia
Authors: Nikolić Biljana , Ristić Mihailo , Bojović Srdjan , Marin Petar D.
Published: May 2007

The essential‐oil compositions of Pinus heldreichii Christ. from Montenegro and Serbia are reported at the population level. Whitebark pine is a sub‐endemic high‐mountain Balkan pine relict of an anthropogenically reduced area, with large morphological diversity and insufficiently clear taxonomic position. In the pine‐needle terpene profile from three populations from Montenegro, and one from Serbia, 101 compounds were detected, 72 of which could be identified (Table 3). The dominant constituents are limonene (26.3%), α‐pinene (17.5%), germacrene D (13.5%), and β‐caryophyllene (10.4%), comprising ca. 67.7% of the essential oil. Medium‐to‐high contents (0.5–10%) of the following 16 additional components were found: β‐pinene, β‐myrcene, α‐humulene, δ‐cadinene, α‐muurolene, (E)‐hex‐2‐enal, β‐gurjunene, γ‐muurolene, isopimarol, camphene, γ‐cadinene, aromadendrene, β‐bisabolene, trans‐β‐farnesene, α‐cadinene, and (Z)‐hex‐3‐en‐1‐ol. The similarity of the populations and the within‐population variability was visualized by principle‐component analysis (PCA) of eleven selected terpenes in 97 tree samples. Cluster and genetic analyses suggest closest connection between the two spatially most‐distant populations I (Montenegro) and IV (Serbia). Based on the profile of the main sesquiterpene components, the studied populations from Montenegro and Serbia are more similar to the populations from Greece and the Central Balkan peninsula (Bosnia and Serbia–Kosovo) than to those on the furthest eastern margin of their natural range (Bulgaria).
Three New Sesquiterpenoids from the Aerial Parts of Homalomena occulta
Authors: Wang Yi‐Fen , Wang Xian‐You , Lai Guo‐Fang , Lu Chun‐Hua , Luo Shi‐De
Published: May 2007

Three new eudesmane‐type sesquiterpenoids, compounds 1–3, and eight known constituents, including mucrolidin (4), 1β,4β,7α‐trihydroxyeudesmane (5), 1β,4β,6β,11‐tetrahydroxyeudesmane (6), oplodiol (7), bullatantriol (8), acetylbullatantriol (9), homalomenol (10), and maristeminol (11), were isolated from the aerial parts of Homalomena occulta. Their structures were determined by interpretation of spectroscopic and mass‐spectrometric data, and their antimicrobial activities toward six different bacterial strains were tested. Most of the compounds showed weak antibacterial activities in an agar‐diffusion assay.
Synthesis, Cytotoxicity, and Antitumor Activity of Lantadene‐A Congeners
Authors: Sharma Manu , Sharma Pritam Dev , Bansal Mohinder Pal , Singh Jaswant
Published: May 2007

Five new derivatives of the pentacyclic triterpenoid lantadene A (=22β‐angeloyloxy‐3‐oxoolean‐12‐en‐28‐oic acid; 1) from the leaves of Lantana camara L. were synthesized, characterized, and screened for their cytotoxicities against four human cancer cell lines. The three most‐potent compounds, i.e., 1, 4, and 6, with IC50 values in the range of ca. 20–29 μM, were further studied for their in vivo tumor‐inhibitory potential upon oral administration in two‐stage squamous cell carcinogenesis, using female Swiss albino mice, papilloma being induced by 7,12‐dimethylbenz[a]anthracene (DMBA), and promoted by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA). The results are discussed in terms of structure–activity relationship.
A Major Triterpenoid Saponin from Gypsophila oldhamiana
Authors: Bai Hong , Zhong Ying , Xie Yan‐Ying , Wang Yuan‐Shu , Liu Lu , Zhou Ling , Wang Ju , Mu Yan‐Ling , Zuo Chun‐Xu
Published: May 2007

A new saponin, gypoldoside A (1), was isolated from the roots of Gypsophila oldhamiana. On the basis of in‐depth NMR‐spectroscopic and mass‐spectrometric analysis, in combination with chemical evidence, its structure was established as 3‐O‐{β‐D‐galactopyranosyl‐(1→2)‐[β‐D‐xylopyranosyl‐(1→3)]‐β‐D‐glucuronopyranosyl}quillaic acid 28‐[α‐L‐arabinopyranosyl‐(1→2)‐α‐L‐arabinopyranosyl‐(1→3)‐β‐D‐xylopyranosyl‐(1→4)‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐fucopyranosyl] ester. Compound 1 was found to be highly active against three different human cancer cell lines, with IC50 values in the low micromolar range.
Dibenzocyclooctane Lignans from the Stems of Kadsura induta and Their Antiviral Effect on Hepatitis B Virus
Authors: Ma Wenhui , Ma Xiaolin , Huang Hai , Zhou Pei , Chen Daofeng
Published: May 2007

Two new dibenzocyclooctane lignans, kadsurindutins A (1) and B (2), were isolated from the stems of Kadsura induta, together with the known, structurally related lignans schisantherin L (3), schisantherin P (4), kadsulignan L (5), and neokadsuranin (6). Their structures and configurations were elucidated by spectroscopic methods (UV, ORD, CD, IR, 1D‐ and 2D‐NMR) in combination with mass‐spectrometric (HR‐MS) techniques. Compounds 1, 5, and 6 showed in vitro antiviral effects on hepatitis B virus.
Synthesis and Antitumor Evaluation of Benzopsoralen Analogues
Authors: Oliveira Ana M. A. G. , Oliveira‐Campos Ana M. F. , Rodrigues Lígia M. , Raposo M. Manuela M. , Machado Antonio E. H. , Nascimento M. São José , Nazareth N. , Pinto Madalena
Published: May 2007

The synthesis of five new tetracyclic benzopsoralen analogues, compounds 2–6, with 9H‐xanthen‐9‐one or 9H‐carbazole frameworks, is described. Their inhibitory effects on the growth of three human tumor cell lines (MCF‐7, SF‐268, and NCI‐460) were evaluated, and discussed in terms of structure–activity relationship, taking into account both geometric and electronic features. Generally, the angular compounds showed significant biological activities, but the arrangement of functional groups also contributed to the overall activity.
Cytotoxic Cardenolides from Streptocaulon griffithii
Authors: Zhang Xiao‐Hui , Zhu Hui‐Lin , Yu Qiang , Xuan Li‐Jiang
Published: May 2007

A new cardenolide, 3‐O‐(β‐glucopyranosyl)acovenosigenin A (1), was isolated from the roots of Streptocaulon griffithii, together with eight known cardenolides, compounds 2–9. All compounds showed significant in vitro inhibition of the proliferation of the human gastrointestinal cancer cell line HGC‐27, with IC50 values in the range of ca. 20–564 nM, taxol being used as positive control. Compound 1 was also found to be strongly cytotoxic against other human tumor cell lines, including A549, MCF‐7, and Hela cells.
Hemmstoffe der Carboxylase
Authors: Kuhn Richard , Beinert Helmut
Published: May 2007

Es wurde der Einfluß verschiedener Stoffe, insbesondere von Benzo‐, Naphtho‐ und Anthrachinonen auf die Aktivität hoch‐gereinigter Hefecarboxylase untersucht. Am wirksamsten waren halogensubstituierte Chinone und Naphthazarine. 2‐Brom‐naphthazarin hemmte unter den eingehaltenen Bedingungen in einer Verdünnung von 1:2 000 000 zu 50%.„Aufgeschlitzte”︁ Chinone von der Art des α.β‐Diacetyl‐äthylens H3·CO·CH: CH·CO·CH3 erwiesen sich gleichfalls als Hemmstoffe. Es waren etwa 7 Moleküle 2‐Brom‐naphthazarin zur Inaktivierung von 1 Mol. Carboxylase erforderlich.
Die Synthese heparinwirksamer Verbindungen aus carboxylierter Cellulose
Authors: Maurer Kurt , Vincke Erich
Published: May 2007

Bei der Bedeutung des Heparins für die Thromboseprophylaxe sind von, verschiedenen Seiten Versuche unternommen worden, leichter zugängliche, ähnlich gebaute synthetische Ersatzpräparate zu schaffen. Diese haben aber alle den Nachteil, bedeutend toxischer als das Heparin zu sein und schwächer blutgerinnungshemmend zu wirken. Es wurde nun versucht, die Toxicität dadurch zu vermindern, daß man durch Oxydation mit Distickstofftetroxyd carboxylierte Cellulosen darstellte, die mit Schwefelsäure verestert wurden. Die schließlich erhaltenen Natriumsalze sind in Wasser leicht löslich; ihre Zusammensetzung wechselt je nach dem Ausgangsmaterial, der Reaktionszeit und der Temperatur. Verschiedene derartige Verbindungen wurden im Tierversuch hinsichtlich ihrer Toxicität und der Wirkung auf Blutbild, Blutdruck und Blutgerinnung geprüft. Es zeigte sich, daß sich mittels des angegebenen Verfahrens Stoffe von geringer Toxicität herstellen lassen, deren blutgerinnungshemmende Wirkung jedoch von derjenigen des Heparins um ein Mehrfaches übertroffen wird.
Das Absorptionsspektrum des Acetyl‐bis‐methylsulfonyl‐methans. Ein Beitrag zur Kenntnis der Gültigkeitsgrenzen der Enolreaktionen bei sulfonylhaltigen Verbindungen
Authors: Böhme Horst , Wolff Günther
Published: May 2007

Die Frage der Konstitution der Acyl‐bis‐alkylsulfonyl‐methane konnte bisher mit chemischen Mitteln nicht entschieden werden. Durch Messung der Ultraviolett‐Absorption wird jetzt das Vorliegen der Ketoform wahrscheinlich gemacht.
Ein neues Fenchen, ζ‐Fenchen (Änderungen des Molekülbaus bei chemischen Reaktionen, VIII. Mitteil.
Authors: Hückel Walter , Kindler Horst
Published: May 2007

Aus β‐Fenchol wird über dessen p‐Toluolsulfonsäureester mit Natriumisopropylat das letzte bisher noch unbekannte Fenchen, das ζ‐Fenchen genannt wird, erhalten. Seine Konstitution wird durch oxydativen Abbau zur cis‐Apocamphersäure bewiesen.