bluuebunny/crossref_metadata_2025 huggingface dataset:
Struktur, Eigenschaften und NMR‐spektroskopische Charakterisierung von Cp2Zr(Pyridin)(Me3SiCCSiMe3)
Authors: Rosenthal Uwe , Ohff Andreas , Baumann Wolfgang , Tillack Annegret , Görls Helmar , Burlakov Vladimir V. , Shur Vladimir. B.
Published: January 2005

Die Substitution des THF‐Liganden in Cp2Zr(THF)(Me3SiCCSiMe3) (1) durch Pyridin ergibt den Komplex Cp2Zr(η1‐NC5H5)(Me3SiCCSiMe3) (3). Im Gegensatz zu 1 ist Komplex 3 stabil in Kohlenwasserstoffen.

In temperaturabhängigen 1H‐ und 13C‐NMR‐Spektren zeigt 3 in Lösung dynamisches Verhalten durch eine Rotation des Alkin‐Liganden. Zusätzlich tritt beim Lösen von 3 in Pyridin ein Austausch zwischen koordinierten und freien Pyridin‐Molekülen auf. Die Kristallstrukturanalyse von 3 belegt eine tetraedrische Koordinationsgeometrie am Zirkonium‐Zentrum bestehend aus den Cp‐, Alkin‐ und Pyridin‐Liganden. Der Komplex 3 reagiert wie Verbindung 1 mit Wasser und Kohlendioxid zu gleichen Produkten.
EPR Spectra of Copper(II) Complexes with N,N‐Dialkyl Amino Acids. The Influence of Water dissolved in Organic Solvents on the Copper(II) Coordination Sphere
Authors: Noethig‐Laslo V. , Paulić N.
Published: January 2005

EPR spectra of four bis(N,N‐dialkyl‐L‐α‐aminoacidato) copper(II) complexes were studied with the aim to determine the effect of the water molecules dissolved in organic solvents on the electronic states of copper(II). It was shown that water dissolved in methylene chloride or dioxan influence the copper(II) electronic states. If the amino acid side chains are long enough to form the aliphatic intramolecular van der Waals contacts, the water molecules will induce the change in the conformation of the whole complex.
Metallorganische Verbindungen der Lanthanoide. 88. Monomere Lanthanoid(III)‐amide: Synthese und Röntgenstrukturanalyse von [Nd{N(C6H5)(SiMe3)}3(THF)], [Li(THF)2(μ‐Cl)2Nd{N(C6H3Me2‐2,6)(SiMe3)}2(THF)] und [ClNd{N(C6H3‐iso‐Pr2‐2,6)(SiMe3)}2(THF)]
Authors: Schumann Herbert , Winterfeld Jörn , Rosenthal Esther C. E. , Hemling Holger , Esser Lothar
Published: January 2005

Eine Reihe von Lanthanoid(III)‐amiden [Ln{N(C6H5)(SiMe3)}3(THF)x] [Ln = Y (1), La (2), Nd (3), Sm (4), Eu (5), Tb (6), Er (8), Yb (9), Lu (10)] wurde durch Reaktion der entsprechenden Lanthanoidtrichloride, LnCl3, mit LiN(C6H5)(SiMe3) erhalten. Die Umsetzung von NdCl3(THF)2 und LuCl3(THF)3 mit den Lithiumsalzen der sterisch anspruchsvollen Amide [N(C6H3R2‐2,6)(SiMe3)]− (R = Me, iso‐Pr) führt zur Bildung der Lanthanoiddiamide [Li(THF)2(μ‐Cl)2Nd{N(C6H3Me2‐2, 6)(SiMe3)}2(THF)] (11) und [ClLn{N(C6H3‐iso‐Pr2‐2,6)(SiMe3)} 2(THF)] [Ln = Nd (12), Lu (13)]. Die neuen Verbindungen wurden durch 1H‐ und 13C‐NMR‐ und Massenspektren, die Neodymderivate 3, 11 und 12 durch Röntgenstrukturanalysen charakterisiert.
Kristallstruktur und Phasenumwandlungen von As(CH3)4I
Authors: Assenmacher Wilfried , Jansen Martin
Published: January 2005

Die Struktur von α‐As(CH3)4I wurde an Einkristallen bei Raumtemperatur bestimmt: kubisch, RG: Pa3, a = 1 198,0(2) pm. Danach hat α‐As(CH3)4I eine neuartige Kristallstruktur, die sich bezüglich der Anordnung von Anionen und Schwerpunkten der komplexen Kationen auf keinen bekannten AB‐Typ zurückführen läßt. Mittels DTA wurden drei Phasenumwandlungen bei 103, 175 und 215°C gefunden. Die Gitterkonstanten der Hochtemperaturphasen (Heizguinier‐aufnahmen) betragen für β‐As(CH3)4I (tetragonal): a = 845,2(2) pm, c = 615,0(2) pm; für γ‐As(CH3)4I (hexagonal): a = 737,7(2) pm, c = 1 082,2(3) pm; und für γ‐As(CH3)4I (hexagonal): a = 705,8(2) pm, c = 1 147(1) pm. β‐ und γ‐As(CH3)4I sind isotyp zu N(CH3)4Cl bzw. As(CH3)4Br.
Zur Kenntnis der Alkalimetallthionylimide
Authors: Mann S. , Jansen M.
Published: January 2005

Es wird über die Darstellung und Charakterisierung neuer Alkalimetallthionylimide MNSO (M = Na, Rb, Cs) und des bekannten KNSO berichtet. Ihre Charakterisierung erfolgte mittels thermoanalytischer, IR‐spektroskopischer und röntgenographischer Methoden. KNSO ist mit RbNSO isotyp (Röntgenpulverdaten): Pnma; KNSO: a = 766,81(2), b = 635,28(1), c = 704,22(2) pm; RbNSO: a = 800,21(1), b = 658,144(9), c = 731,39(1) pm. Für CsNSO (kubisch; Pm3m; a = 464,78(3) pm) wurde unter Annahme eines rotationsfehlgeordneten [NSO]−‐Anions ein Strukturmodell entwickelt. Auf Grundlage der Bindungsabstände und ‐winkel des Anions wurden GVFF‐Kraftkonstantenrechnungen durchgeführt.
Molekülstruktur und intermolekulare Koordination von acylsubstituierten Chelatkomplexen Schiffscher Basen
Authors: Wiesemann F. , Krebs B. , Görls H. , Jäger E.‐G.
Published: January 2005

Die Kristall‐ und Molekülstruktur von vier Schiff‐Base‐Komplexen mit zusätzlichen Acylgruppen an den meso‐Positionen der Liganden wurde mittels Röntgenstruktur‐analyse untersucht. Im Nickelkomplex 5 und im Kupferkomplex 4 a ist der Sauerstoff der Acetylgruppen in den Chelatsechsringen koordiniert, während die Benzoylgruppen als meso‐Substituenten wirken. Im Gegensatz zum Nickelkomplex 5 und zu den Kupferkomplexen 4 b und 6 a, die keinerlei intermolekulare Koordination der freien Carbonylgruppen zeigen, bildet 4 a durch intermolekulare side‐on‐Koordination beider Benzoylgruppen 1 D‐Koordinationspolymere mit stark verzerrt oktaedrischer Koordination des Kupfers. Die Molekülverkettung unterscheidet sich deutlich von der im Cobaltkomplex 3 b, bei dem nur eine der meso‐Carbonylgruppen koordiniert ist, so daß treppenartige Ketten mit Koordinationszahl 5 des Cobalts und einem kürzeren Metall‐Oaxial‐Abstand entstehen. Die zentrale [Cu4O4]‐Einheit in 6 a hat eine cyclooctan‐ähnliche Boot‐Konformation mit quadratisch‐pyramidal koordiniertem Kupfer anstelle der Cubanstruktur mit trigonal‐bipyramidaler Koordination in der α‐Form von 6 b.
Transition Metal Chemistry of Main Group Hydrazides. 17. Triphosphine derived from phosphanyl hydrazide as a building block for hetero trimetallic compounds. Synthesis and coordination chemistry of ((Me2P)2NN(Me)(PMe2))
Authors: Reddy V. Sreenivasa , Katti Kattesh V.
Published: January 2005

The new triphosphine (Me2P)2NN(Me)(PMe2) (1), has been synthesized in pure form by the reaction of methylhydrazine with dimethylchlorophosphine in the presence of triethylamine. This triphosphine represents a bridge between phosphinoamine (>PN(R)P<) and phosphanyl hydrazide (>PN(R)N(R)P<) backbones. Reaction of 1 with cis‐[W(CO)4(NHC5H10)2] proceeds via two coordination modes to give four‐membered MPNP and five‐membered MPNNP metallacyclic frameworks. The tungsten complex cis‐[W(CO)4{(Me2P)2NN(Me)(PMe2)}] (2) possessing an uncoordinated phosphine moiety to prepare multimetallic organometallic compounds. For example, reactions of 2 with PdCl2(PhCN)2 and PtCl2(COD) produced the trimetallic complexes consisting of W(0)Pt(II) and W(0)Pd(II) centers respectively in good yields. The different isomers of these trinuclear complexes have been clearly identified by 31P NMR spectroscopy.
Die 2,6‐Diisopropyl‐phenylgruppe als sperriger Substituent in Bor‐Stickstoff‐Verbindungen. II [1]
Authors: Luthin W. , Stratmann J.‐G. , Elter G. , Meller A. , Heine A. , Gornitzka H.
Published: January 2005

Die HF‐Eliminierung aus Fluorbis(amino)boranen des Typs R′ (Me3Si)NBFNHR (R = 2,6‐)Me2CH)2C6H3, R′ = Me (Ia), CH2Me (Ib), CHMe2 (Ic), CMe3 (Id), SiMe3 (Ie), R (If)) mit t‐Butyllithium im Molverhältnis 1:1 führt zu den Amino‐imino‐boranen (IIa–f), die – abhängig von der Größe des Substituenten R′ – unterschiedliche thermische Stabilität aufweisen. IIa – c und IIe dimerisieren zu den Diazadiboretidinen IIIa – c und IIIe. IId ist bis über 200°C stabil, während sich IIf bei dem Versuch seiner Isolierung zum Bor‐Methyl‐substituierten Diazasila‐boretidin IVf umlagert. Führt man die gleiche Umsetzung mit t‐Butyllithium im überschuß (Molverhältnis 1:2) durch, erhält man fast ausschließlich die Bor‐t‐Butyl‐substituierten Diaza‐sila‐boretidine Va – Vf.

Alle Verbindungen sind elementaranalytisch (C, H) und spektroskopisch MS, NMR (1H, 13C, 15N (teilweise), 19F, 29Si) charakterisiert. Charakteristische IR‐Banden werden für die Amino‐imino‐borane (II) angegeben. Eine Röntgenstruktur‐analyse wurde von IVf angefertigt.
31P MAS‐NMR an Phosphoroxidsulfiden — experimentelle Bestimmung und quantenchemische Berechnung der Tensoren der chemischen Verschiebung
Authors: Kutzelnigg W. , Fleischer U. , Frick F. , Hoffbauer W. , Jansen M. , Grimmer A. R.
Published: January 2005

Mittels hochaufgelöster 31P MAS‐NMR‐Spektroskopie und entsprechender Analyse der Seitenbandspektren werden in der homologen Reihe P4O6Sn (n = 0–4) die Hauptwerte der Verschiebungstensoren bestimmt und die Lagen der zugehörigen Hauptachsen im Molekül abgeleitet. Innerhalb der experimentellen Genauigkeit zeigen die kernmagnetischen Abschirmungstensoren axiale Symmetrie. Man gelangt daher zu Aussagen über die Orientierung der Tensoren im Molekül, was in der Regel in polykristallinen Proben nicht möglich ist.

Die Tensorhauptwerte der dreiwertigen Phosphoratome in P4O6S weichen bezüglich der Anisotropie und Axialität der Tensoren scheinbar von denen der anderen Verbindungen ab. Ursache hierfür ist ein dynamischer Effekt: die Rotation des Moleküls um die PS‐Bindungachse. Die Ergebnisse, im besonderen das durch die Rotation verursachte ungewöhnliche Verhalten in P4O6S stehen in Einklang mit ab‐initio Rechnungen mit der IGLO Methode.
Mixed Chloro(dialkylamido) Complexes of Zirconium and Hafnium
Authors: Brenner Simon , Kempe Rhett , Arndt Perdita
Published: January 2005

Chloro(dialkylamido) complexes of the type (R2N)2MCl2(THF)2 (R = Me, Et; M = Zr and R = Me; M = Hf) were synthesized in a conproportionation reaction by adding an equimolar amount of the corresponding M(NR2)4 to an ether slurry of MCl4 in the presence of THF. X‐ray crystal structure determinations of (Et2N)2ZrCl2(THF)2 (1 a) and (Me2N)2ZrCl2 · (THF)2 (1 b) reveal a distorted octahedral coordination geometry where the sterically demanding dialkylamide ligands force the chloride and the THF ligands out of their ideal position. Dynamic NMR investigations indicate an equilibrium of complexes with coordinated THF at low temperature in accordance with the structure determined by X‐ray crystallography and of chloro‐amido complexes that do not bind THF (at higher temperature).
Preparation, crystal structure, and infrared characterization of the first thiocyanato‐oxy‐antimonate(III) [(CH3)4N]2[Sb6O4(NCS)12]
Authors: Bertazzi N. , Alonzo G. , Saiano F. , Battaglia L. P.
Published: January 2005

The salt [(CH3)4N]2[Sb6O4(NCS)12] is the first identified thiocyanato‐oxy‐antimonate(III) complex. Reported are details of the synthesis, relevant infrared data and its x‐ray structure. The compound crystallizes in the triclinic space group P1 with Z = 2 (C10H12N7O2S6Sb3) and unit cell dimensions a = 11.314(6), b = 12.846(3), c = 8.679(2) Å; α = 91.93(3)°, β = 90.31(3)° and γ = 99.13(3)°. It contains centrosymmetric [Sb6O4(NCS)12]2− anions packed with isolated tetramethyl‐ammonium cations. The fundamental structural element of the anion is provided by the fusion of three SbOSbO rings forming a zig‐zag portion of a ribbon, only slightly pleated. Peculiar is the unequivalence of the six thiocyanate ligands, though all primarily N‐bonded to antimony atoms. Three thiocyanates are terminal while other three are asymmetrically N‐bridging between two centers; two of this latter type are also interconnecting the anions via Sb⋅⋅⋅S contacts. There are three different antimony environments, the primary bonding at Sb being to one nitrogen and three oxygens, to one oxygen and three nitrogens and to two atoms of each type.
Ternäre Thalliumplatin‐ und Thalliumpalladiumchalkogenide Tl2M4X6. Synthesen, Kristallstruktur und Bindungsverhältnisse
Authors: Bronger W. , Bonsmann B.
Published: January 2005

Die Verbindungen Tl2Pt4S6, Tl2Pt4Se6, Tl2Pt4Te6 und Tl2Pd4Se6 sind durch Schmelzreaktionen aus den jeweiligen Elementen oder durch die Umsetzung von Thalliumcarbonat, Übergangsmetall‐ und Chalkogenpulver im Temperaturbereich zwischen 400°C und 950°C darstellbar. Röntgenographische Untersuchungen an Einkristallen und an pulverförmigen Proben ergaben, daß die Verbindungen in einem neuen Strukturtyp kristallisieren, der als Stapelvariante schon bekannter Atomanordnungen der Alkalimetallplatinchalkogenide A2Pt4X6 (A ≙ Alkalimetall, X ≙ S, Se) aufgefaßt werden kann. Die geringen Atomabstände Thallium‐Platin bzw. Thallium‐Palladium deuten in übereinstimmung mit den Ergebnissen von Extended‐Hückel‐Rechnungen auf eine kovalente Bindung zwischen dem Hauptgruppen‐ und dem übergangsmetall hin.
Zur Bildung von Vinylverbindungen des Lanthans und Lutetiums
Authors: Thiele Karl‐Heinz , Seifert Ronald
Published: January 2005

Permethyllanthanocenchlorid reagiert mit Vinyllithium unter Vinylkopplung zu dem Butadienkomplex [Li(DME)3] [Cp2*La(C4H6)] (1). Ausgehend von der entsprechenden Lutetiumverbindung konnte dagegen das gesuchte Cp2*Lu(CHCH2) · LiCl · DME (4) als wenig beständige Substanz erhalten werden. Als stabilere Alkenylverbindungen werden das Cp2*LaCPhCMe2 · 2 THF (2) und Cp2*LuCPhCMe2 · MgCl2 · DME (3) beschrieben. Die Charakterisierung der Komplexe erfolgte durch ihre 1H‐ und 13C‐NMR‐Spektren.
Monomeres Trilithium‐tris[tert‐butyldimethylsilylamido]phenylsilan, PhSi[NLi(THF)SiMe2CMe3]3 ‐‐ Darstellung und Kristallstruktur
Authors: Hemme I. , Klingebiel U. , Freitag S. , Stalke D.
Published: January 2005

Lithiiertes tert‐Butyldimethylsilylamin reagiert mit Trifluorphenylsilan im molaren Verhältnis 2:1 bzw. 3:1 zu den Bis‐ und Tris(silylamino)silanen 1 [(Me3CSiMe2NH)2 · SiFPh] und 2 [(Me3CSiMe2NH)3SiPh]. In der Reaktion von 2 mit n‐BuLi in Hexan/THF entsteht das Trilithiumderivat 3 [Me3CSiMe2NLi(THF)]3SiPh. 3 kristallisiert als Monomer und bildet im Kristall drei planare, viergliedrige (LiNSiN)‐Ringe. Die Ergebnisse der Kristallstrukturanalyse von 3 werden mitgeteilt.
Ethical dilemmas in context: Some preliminary questions
Authors: Bond Meg A.
Published: January 2005

I have tried to build on O'Neill's thought‐provoking paper by examining two influences that shape and define ethical dilemmas in the community: our personal agendas and the broader context. The first influence is the way in which our personal and professional values shape our agendas for community work. The way these agendas frame the choices for action are a force to be recognized separate from the question of who constitutes our community constituency. Our values may push us into proactive roles and we must face the way our actions make personal/political statements. The broader context of the community situation and the ways in which resource limitations frame the ethical question also need to be actively recognized. Otherwise there is a danger of making the psychologist the victim by posing the ethical dilemma as a question of how they alone should find a solution.

The nature of our personal agenda must be clear before we ask “responsible to whom?” The broader context must be considered before we ask “responsible for what?”
Toward a synergism of rural development and community psychology
Authors: Omprakash S.
Published: January 2005

Conclusion

The community psychologist should be attuned to the phenomenon that deprived communities are not always attracted by goals that are understandable to the middle‐class power structure. Persons in a constant battle against poverty settle at first for immediate visible gains. An increase in the number of children getting lunch at school is tangible; a revision of the curriculum to produce better competence in mathematics is not quite so tangible.
Context and process: An ecological view of the interdependence of practice and research: An invited address by James G. Kelly
Authors: Altman David G.
Published: January 2005

James G. Kelly has made important and wide‐ranging conributions to community psychology. The field is fortunate to have a member with his vision and commitment. In the paper presented here, Jim discusses the advantages that arise when scientists and citizens work as collaborative partners in community research. As with his previous work, his ideas provide new insights into the role of community psychology in and for the community.
Refining fit: Conceptual and methodological challenges
Authors: Pargament Kenneth I.
Published: January 2005

Conclusions

In some respects the development of research on person‐environment fit has paralleled that of other methods and constructs in psychology such as psychotherapy and social support. Initial efforts have focused on basic questions such as: “Does psychotherapy work?; What are the correlates of social support?; and Is fit good for you?” However, as research has accumulated, it becomes clear that the initial questions raised were too simple (Gottlieb, 1981; Kiesler, 1971). Like psychotherapy and social support, some kinds of fit may be good for some people, in some places, some of the time, and in some ways. The challenge for researchers in the area is the development of models and methods that capture more fully the richness of the transaction between person and environment.
Development of the design of fermenters with energy introduced by aerating gas, having contacting devices
Authors: Prokopenko V. D. , Viesturs U. E.
Published: December 2004

This paper deals with fermenters with energy introduced by gas phase (FG), having contacting devices, of laboratory, pilot and industrial scale.

It is an attempt to state the possible use of such apparata in view of the rheological properties of the culture and intensity of mass transfer.

There has been proved the necessity to introduce additional energy to speed up the circulation, determined by requirements of rational construction and definite demands set forth by the very process of microorganism cultivation (prevention of oxygen limitation, flotation, foam regulation etc.).
Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC). I. Separations of carbohydrates, organic acids and lipids
Authors: Gey M.
Published: December 2004

Suitable and optimized chromatographic separation systems for HPLC analyses of mono‐, di‐ and oligomeric carbohydrates, organic acids (e.g. gluconic acid, α‐ketoglutaric acid), phospholipids (PE, LPE, LPC, PC, SPH) and neutral lipids (squalene, cholesterol) are demonstrated.

Applications of HPLC technique are separation examples of sugars from hydrolyzed starches which were isolated from potatos, calculations of organic acids in fermentation mediums and determinations of neutral lipids and phospholipids which were isolated from microbial biomass.

The liquid chromatographic separations are based on self‐packed highly efficient (approximately 80 000 theoretical plates per meter, N/m) glass columns.
Influence of the mycelium growth conditions on the production of amylolytic, proteolytic and pectinolytic enzymes by Aspergillus niger C
Authors: Fiedurek J. , Ilczuk Z. , Łobarzewski J.
Published: December 2004

Various nitrogen and carbon sources, as well as natural products, were examined as inducers of the production of amylases, proteases and pectinases by A. niger C. A. niger C grown on wheat bran extract medium provided culture supernatants with the highest enzymatic activities. Some culture conditions, e.g. pH, medium temperature and time period of cultivation, were optimalized to improve the growth and enzymes biosynthesis by A. niger C.
Biochemical reactions of Brevibacterium flavum depending on medium stirring intensity and flow structure
Authors: Ruklisha M. P. , Vanags J. J. , Rikmanis M. A. , Toma M. K. , Viesturs U. E.
Published: December 2004

Authors have studied the dependence of the physiological and biochemical characteristics of lysine producers Brevibacterium flavum on medium stirring intensity upon constant pO2 during fermentation processes. Various factors affecting the rate of biochemical reactions in cells upon a changeable intensity of medium stirring in apparata with turbine stirrers; oxygen mass transfer intensity in the system; stirring characteristics in the fermenter; biochemical changes in the cells due to gradients of energy introduced by the stirrer in the fermenter, etc. have been studied. A comparison of the experimentally established values, characterizing macrostirring (e) and microstirring (KR), with the physiological and chemical characteristics of bacteria during fermentation made us suppose that the character of the kinetic energy distribution in the volume of fermenter is one of the factors regulating bacterial metabolism. Besides, there exists the value ecrit, upon which there can be observed essential changes of the physiological and biochemical properties of the cells. The effect of medium flows upon the cells is characterized by index Fstress, which takes into account both, the possible presence of the cells in the zone with e ≧ ecrit, and the degree of medium flow and cell interaction, numerically equal to value (e – ecrit)0.5.
Microorganisms for lipids
Authors: Ratledge C.
Published: December 2004

Micro‐organisms have often been considered for the production of oils and fats as an alternative to agricultural commodities. However, with the continuing low cost of agricultural production of oil‐seeds, biotechnology has little to offer in the way of competition against such items as soybean oil, groundnut oil, and even polyunsaturated oil such as sunflower oil even though good facsimiles of these oils could be produced. It is now clear that if we are to use microorganisms to produce lipids, i.e. Single Cell Oil, then these must be highly specific ones which are currently expensive to obtain from agricultural sources. In particular, the possible production of a cocoa‐butter substitute using mutated yeast cells is reviewed here as well as the production of highly polyunsaturated fatty acids (PUFAs) using various species of mould. With regard to producing a cocoa‐butter equivalent fat, it is necessary to identify not only a cheap carbon source on which the yeast may grow (this is now considered likely to be lactose arising from whey) as well as deriving a mutant strain of the yeast which will accumulate large amounts of stearic acid within the oil. The recent work carried out in The Netherlands and New Zealand to achieve these goals is described. With regard to polyunsaturated fatty acid production, various prospects exist and indeed, the commercial production of one acid, gamma‐linolenic acid, is now being produced commercially in both the U.K. and Japan. The background work leading to this product is described and opportunities for other PUFAs being produced biotechnologically are discussed.
Aggregation kinetics of saccharomyces cerevisiae on solid surfaces
Authors: Schmidt R.
Published: December 2004

In the colonization experiments of yeast cells on stainless steel surfaces the analyzed minimum of the colonization rate was found in a roughness interval between a highly polished sample and a very rough surface. This phenomenon is a problem of the shear forces and of adhesion.

On the basis of reaction kinetics it was possible to analyze the change between an unstable and a stable cell‐cluster. The analysis of the energy needed for forming a stable cluster tends toward values known from the stochastic simulation of cluster formation in an undisturbed region. But the potential function is not clear which describes the interactions between the cells and the forming cluster in the reaction field. This is a problem of special materials‐testing which is not established.

For producing plants it is of high interest to note that it are not the most highly polished surfaces that are the best.
Application of vesicle chromatography in protein purification
Authors: Kleine R. , Woehlecke H. , Ehwald R.
Published: December 2004

A recently described vesicular packing material (VP) representing clusters of microcapsules (derived from plant cells) was tested with respect to its application for protein purification. Protein elution behaviour was investigated with 28 defined proteins and several protein containing preparations and biological fluids. All proteins were eluted with a neutral buffer without retardation as peaks in the permeable or excluded fraction. Due to its sharp separation limits VP can be used for the separation of proteins with small differences in size. In special cases, proteins of nearly equal molecular weight (e.g. carboxypeptidase A and pepsin) may be separated due to differences in the electrical charge of the protein molecules and resulting differences in the electric in the electrical charge of the protein molecules and resulting differnces in the electric interaction with the negatively charged polygalacturonan matrix of the vesicle membrane (cell wall).

Vesicle chromatography is a biocompatible process. The VP may be applied on a large scale. Complete separation between excluded and permeable proteins may be reached if the columns are loaded with concentrated protein samples (e.g., blood plasma). Size fractionation by the VP seems to be applicable in the following fields:

Preparative separation of an excluded protein from an excess of permeable macromolecules, especially if the difference in STOKES' diameter is too small for an effective separation by gel chromatography or conventional membrane techniques.

Preparative separation of permeable proteins from an excess of excluded proteins.

Chromatography of proteins in the presence of alcohol, polyethylene glycol or detergents.
Biosynthesis, preparation and properties of ascochitine
Authors: Foremska E. , Kostecki M. , Chełkowski J.
Published: December 2004

This paper is concerned with the biosynthesis of a high yield of mycotoxin ascochitine by a Ascochyta pisi strain ATCC 66101 on solid substrate with a description of the subsequent procedure of extraction, purification and crystallization. Spectroscopic, chromatographic and antibiotic properties of the mycotoxin are reported.
Fixation of thermostable β galactosidase on zeolithes with controlled hydrophobicity
Authors: Zentgraf B. , Gwenner C.
Published: December 2004

Thermostable and hydrophobic β galactosidase of Bacillus sp. TP32 is fixed on zeolithes of controlled hydrophobicity. Thereby, the Si/Al ratio of the zeolithe is an important quantity for controlling the zeolithe hydrophobicity and with it the rate and efficiency of enzyme fixation. The fixation properties improve from NaY via Us(w) to mordenite and Us‐Ex.

Mordenite β galactosidase is highly active in SOERENSEN phosphate buffer, dodecanole, and ethylene glycole at 70°C using ortho nitrophenyl β D‐galactopyranoside (ONPG) as substrate. Further preparations of zeolithe β galactosidase have more or less disadvantages in regard to hydrolysis of ONPG at elevated temperature, as well as rate and efficiency of enzyme fixation exept of Us‐Ex β galactosidase in ONPG‐containing dodecanole.
Determination of the best nutrient medium for the production of L‐lactic acid from beet molasses a statistical approach
Authors: Monteagudo J. M , Rincón J. , Rodríguez L. , Fuertes J. , Moya A.
Published: December 2004

Optimization studies have been carried out for the production of L‐lactic acid from the fermentation of beet molasses by Lactobacillus delbrueckii. A PLACKETT‐BURMAN Design and a Central Composite Design have been used to determine the most suitable nutrient medium for obtaining a maximum cell concentration. A second‐order polynomial empirical model relating both the cell and nutrient concentrations was formulated. The variables selected for the study were Yeast Extract, Peptone, Tween 80 (antifoam), MgSO4 · 7H2O, MnSO4·4H2O, FeSO4 · 7H2O and K2HPO4/KH2PO4. Among them, only Yeast Extract and Peptone were found to significantly affect the cell concentration. A maximum cell yield was found when the concentrations of Yeast Extract and Peptone were, respectively, 5.31 g/l and 5.08 g/l. All conclusions are restricted to the experimental range studied.
Lipid production and fatty acid composition of selected strains belonging to Mucorales
Authors: Čertík M. , Berhan S. Sereke , Šajbidor J.
Published: December 2004

The lipid accumulation, fatty acid composition and γ‐linolenic acid (GLA) production by 28 strains belonging to Mucorales were investigated. The lipid content varied from 5 to 30% on dry biomass and the percentage of γ‐linolenic acid in total intracellular lipid was in a range from 2.5 to 15.4% (w/w). The best yield of γ‐linolenic acid (expressed as mg GLA per 1 g biomass) was found for Mucor mucedo CCF – 1384 (28.4) and Cunninghamella echinulata CCF – 103 (25.1).
Production of oxytetracycline and rifamycins B and SV with cells immobilized on glass wool
Authors: Farid M. A. , El Diwany A. I. , El Enshasy H. A.
Published: December 2004

The antibiotic producing microorganisms Streptomyces rimosus PFIZER 18234‐2 and Amycolatopsis mediterranei CBS 42575 were immobilized in glass wool for the production of oxytetracycline and rifamycins B and SV. The growth of the immobilized cells was dependent on the type of the microorganism and on the amount of glass wool as well. After 5 exchanges of the medium, 530 mg O.T.C., 2138 mg rifamycin B and 8672 mg rifamycin SV were maintained. The periodic batch culture was continued for 20 days.
Extracellular amylase synthesis by Bacillus globisporus BH‐1b
Authors: Bandyopadhyay A. , Sen S. K. , Pal S. C.
Published: December 2004

Despite the prevalence of starch‐hydrolyzing enzymes in bacilli, relatively few have been studied in detail. In an attempt to isolate an effective α‐amylase‐producing strain, Bacillus globisporus BH‐1b has been isolated. The strain requires few nutritional supplements and shows induction in the presence of galactose. 2% potassium nitrate and pH 7.2 emerged as optimum for the fermentation medium. The durability of the enzyme has also been tested at a low pH and a high temperature.
Behaviour of Candida utilis during growth in relation to Mg2+ and K+ concentration in sugar cane molasses
Authors: Otero M. A. , Reyes A.
Published: December 2004

Magnesium and potassium ions are present in sugar cane molasses in a concentration of about 0.3% and 2.5%, respectively, which is high enough to support biomass production from Candida utilis. Culture broth with 40 g/l of total reducing substances supplemented by the addition of 1 ppm of Mg2+ leads to a higher yield (Y x/s) in batch fermentation experiments. The subsequent addition of Mg2+ up to 10 ppm decreases the yield coefficient from 0.53 to 0.42 without affecting the growth rate. Fermentation media supplemented with 1 to 10 ppm of K+ decreased both the yield coefficient and the specific growth rate. A Mg/K ratio of about 0.1 seems to be optimal for yeast biomass propagation.
Transformation of ferulic acid by soil bacteria Nocardia provides various valuable phenolic compounds
Authors: Malarczyk E. , Rogalski J. , Leonowicz A.
Published: December 2004

Nocardia autotrophica was grown in a medium containing ferulic acid and 14C‐ferulic acid, labelled in various parts of a particle as a main carbon source. After incubation, the products were analyzed by thin layer, high performance liqid and gas chromatography and by IR and NMR spectra methods. The products detected were caffeic acid, catechol, coniferyl alcohol, eugenol, guaiacol, hydrocaffeic acid, isoeugenol, isoferulic acid, isovanillic acid, p‐hydroxybenzoic acid, protocatechuic acid and aldehyde, vanillic acid, and vinylguaiacol. A liberation of 14CO2 during cultivation was noticed.
Aerobic degradation of toluene in a closed chemostat with and without a head space outlet
Authors: Ray P. , Löser C.
Published: December 2004

The present paper describes the continuous aerobic cultivation of a Pseudomonas strain with toluene as the substrate in a closed chemostat with oxygen or air as the gas phase. Due to the constant supply of a nitrogen‐saturated aqueous medium, nitrogen passes from the liquid phase of the chemostat into the gas phase (head space). This results in an increasing nitrogen content (asymptotic approach to 100%). The concomitant decrease in the partial pressure of the oxygen in the gas phase finally leads to an oxygen limitation for the bacteria in the medium and an incomplete toluene degradation. The critical nitrogen content of the gas phase at which oxygen limitation begins depends on the toluene concentration in the incoming medium. However, when the gas is continuously removed from the head space, the nitrogen content reaches a steady‐state value of less than 100%, depending on the flow rate of the outgoing gas. The oxygen limitation and the associated incomplete toluene degradation can be prevented in this way. The method of gas removal from the head space to avoid oxygen limitation is also applicable when the reactor is supplied with air instead of oxygen. Waste waters contaminated with highly volatile pollutants can thus be biologically decontaminated under aerobic conditions, without shifting the pollution problem from the liquid to the gas phase.
Kinetics of the utilization of different C sources and the cellulose formation by Acetobacter xylinum
Authors: Geyer U. , Klemm D. , Schmauder H.‐P.
Published: December 2004

Different methylated glucose derivatives and cellobiose were examined as the carbon sources for growth and cellulose formation by Acetobacter xylinum. HPLC studies were carried out to gain information about the kinetics of the utilization of the C sources used. The type and yields of the synthesized cellulose were described. Besides glucose, cellobiose was a substrate for the synthesis of this polysaccharide by the bacteria. Other methylated derivatives of glucose were not accepted for a comparable synthesis of this polymer. An estimation of citrate in an unmodified culture liquid (SH medium) showed utilization in a late phase of cultivation. The influence of this organic acid on the pH value, cellulose synthesis and growth is described. By the application of citric acid as a sole carbon source “gel‐like” forms of cellulose were formed generally.
Separation of D‐forms and L‐forms of DL‐aspartic acid derivatives by the enzyme subtilisin DY
Authors: Milev L. , Vezenkov L. , Yotova L.
Published: December 2004

The ability of the enzyme subtilisin DY for the synthesis of derivatives of DL‐aspartic acid which are differently N and C‐terminal protected and semiproducts of the peptide synthesis was investigated. The enzyme reaction was characterized by high yields and a comparatively short reaction time. Two of the substrates, Z‐D,L‐Asp‐(OMe)2 and PhAc‐D,L‐Asp‐(OMe)2, were hydrolyzed for about 15 min; the reaction time for Boc‐D,L‐Asp‐(OMe)2 was 2.5 h. The values for the MICHAELIS constants obtained for Z‐D,L‐Asp‐(OMe)2 (Km = 0.576 mM) and PhAc‐D,L‐Asp‐(OMe)2 (Km = 0.300 mM) showed a high affinity of the enzyme to the substrates. For Boc‐D,L‐Asp‐(OMe)2 the affinity of the enzyme is considerable lower (Km = 14.07 mM).

The results of these investigations can be effectively used for the separation of N‐protected derivatives of D,L‐aspartic acid and with a high probability also for other amino and racemic forms.
Trends in biotechnology: Sustainable technology development: From high tech to Eco Tech
Authors: Moser A.
Published: December 2004

Biotechnology as a multidisciplinary and transdisciplinary field of science and engineering is regarded to be a key technology for the future, able to essentially contribute to sustainable development. In the first part of this paper, a critical analysis of the status quo in biotechnologies is given in the area of pharmaceutical, agricultural, environmental, and industrial biotechnology as well as food biotechnology. Here the general potential becomes clear, but also a series of disadvantages which are partly the result of the existing paradigm in science and technology and partly in direct connection to bioprocessing itself. Nevertheless, these biotechnologies will contribute to sustainable development, but mainly in a shallow sense of survival and livelihood.

In the second part of this paper, another new dimension in bioprocessing is elucidated, which is in agreement with the new ecological, holistic world view. Here the so‐called “eco‐principles” are derived from a systems analysis of the ecosphere and represent the intelligence of nature as the result of evolution. The eco‐principles will serve as guidelines for the general eco‐restructuring of technology, being a drastic change within the next 2–5 decades. For the applying of eco‐principles, a quantitative measure for sustainability in technology was developed (“sustainable process index”), which will enable us to design the new technology paradigm called “Eco Tech”. Ecological security and social equity, together with economic efficiency will define sustainable technology development in a deeper sense.

Following this route, a completely new dimension of biotechnology will be reached, where the technosphere is fully embedded into the natural cycles of the ecosphere on a local basis.
Colonisation of seedling roots by 2,4‐D degrading bacteria: A plant‐microbial model
Authors: Zwieten L. , Feng L. , Kennedy I. R.
Published: December 2004

The development of model plant‐microbial associations between Gram negative soil microbes capable of degrading phenoxyacetate herbicides, such as 2,4‐D and 2,4‐D methyl ester, and the crops canola and wheat was described. Both an Acinetobacter baumannii pJP4 transconjugant and Alcaligenes eutrophus JMP 134 colonised non‐parasitically on the roots of sterilised seedlings in a hydroponic system. Laser scanning confocal microscopy has shown that colonisation occurred both on the root surface and deeper inside the mucilage layer or inside some surface root cells. When 2,4‐D was added to the hydroponic medium supporting the growth of those seedlings colonised by 2,4‐D degrading bacteria, the gas chromatographic analysis showed a rapid decrease in the concentration of this herbicide. These bacteria colonising the root system were shown to be responsible for the degradation of 2,4‐D. Plants inoculated with the 2,4‐D degrading microbes were subsequently found to be less susceptible to damage by the herbicide in such hydroponic systems.
Characterization of biosurfactants and their use in pollution removal – State of the Art. (Review)
Authors: Banat I. M.
Published: December 2004

Surface‐active compound of biological origin (biosurfactants) have only been described in the past few decades. With the advantage of biodegradability and production on renewable resources, biosurfactants have been gaining prominence and their applications are becoming wider. So far, literature contains mixed reports on the successes of the applications of biosurfactants and their economical viability. They remain compounds which are not very well understood, yet, with several important applications. The target industries for biosurfactant use are the petroleum remediation industries and environmental conservation agencies. These industries, however, seem reluctant to use them for fear of dealing with microbes or microbial products. This includes cleaning up oil spills from the environment, remediation of metal‐contaminated soils or waste streams, mobilizing heavy oil sludge and enhanced oil recovery. The importance of biosurfactants, their production, characteristics and limited successes and applications in oil pollution remediation and oil storage tank cleaning are discussed.
Airborne bacteria and fungal spores in the indoor environment. A case study in Singapore
Authors: Goh I. , Obbard J. P. , Viswanathan S. , Huang Y.
Published: December 2004

The concentration of airborne fungal spores and bacteria as related to room temperature, humidity and occupancy levels within a library building in Singapore was determined. Measurement of indoor air quality with respect to microorganisms is of particular importance in tropical environments due to the extensive use of air‐conditioning systems and the potential implications for human health. This study has revealed a number of interesting relationships between the concentrations of fungal spores and bacteria in relation to both environmental and human factors. The levels of fungal spores measured in the indoor environment were approximately fifty times lower than those measured outside, probably because of the lowered humidity caused by air‐conditioning in the indoor environment. The variation in fungal spore concentration in the outdoor environment is likely to be due to the diurnal periodicity of spore release and the response to environmental factors such as light temperature and humidity. The indoor concentration of fungal spores in air was not clearly correlated to concentrations measured in air outside of the library building and remained relatively constant, unaffected by the difference in the numbers of occupants in the library. In contrast, the indoor concentrations of bacteria in air were approximately ten times higher than those measured outdoors, indicating a signficant internal source of bacteria. The elevated levels of indoor bacteria were primarily attributed to the number of library occupants. Increased human shedding of skin cells, ejection of microorganisms and particulates from the respiratory tract, and the transport of bacteria on suspended dust particles from floor surfaces probably accounts for the strong positive correlation between occupancy levels and the concentration of bacteria in internal air.
Phase behavior of discotic liquid crystalline polymers and related model compounds
Authors: Kranig Wolfgang , Hüser Bernhard , Spiess Hans W. , Kreuder Willi , Ringsdorf Helmut , Zimmermann Herbert
Published: December 2004

The phase behavior of liquid cyrstalline polymers and oligomer model compounds with alkylated tripheylenes (see figure) as the mesogenic core is studied using a combination of optical microscopy, DSC and 2H NMR. The information provided by NMR provides unique insights into the behavior of liquid crystalline phases.

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Chemically modified metal surfaces—a new class of composite materials
Authors: Stratmann Martin
Published: December 2004

This promising method of chemically modifying reactive metal surfaces with organic molecules prior to the attachment of polymers could have a significant impact on work aimed at the optimization of the performance of composite materials. Strong chemical bonds can be formed between a suitably prepared metal surface and certain monomers, which resist even an electrochemical polarization of the interface at large cathodic or anodic overpotentials. These chemical bonds can, however, only be achieved if a suitable structure and reactivity is generated, for example, by using electrochemical techniques. Therefore, further technological progress in this important area requires the cooperation of scientists from rather different scientific disciplines like electrochemistry, surface science and organic chemistry, in order to optimize the structure of the organic monomers and to provide the best possible bonds to the different metals in use, taking into account the rather different reactivity of technologically important media.
Molecular recognition directed self‐assembly of supramolecular liquid crystalline polymers from complementary chiral components
Authors: Fouquey Claudine , Lehn Jean‐Marie , Levelut Anne‐Marie
Published: December 2004

The self‐assembly of intelligent supermolecular materials, for example, liquid crystalline polymers, is the subject of this communication. Employing units based on tartaric acid in the molecular recognition process (see figure) allows the effects of chirality to be investigated as the recognition which occurs at a molecular level is reflected in the properties of the macroscopic mesophases formed.

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Aligned molecular sieve crystals
Authors: Caro Jürgen , Finger Gerd , Kornatowski Jan , Richter‐Mendau Jürgen , Werner Lutz , Zibrowius Bodo
Published: December 2004

The controlled incorporation of guest molecules in zeolites opens the way to novel materials with desirable optical, magnetic, or electronic properties. The properties of the guests are often direction dependent and therefore the bulk orientation of the host matrixes (see figure) in an electric field can lead to greatly enhanced performance.

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White light emission from C60 molecules confined in molecular cage materials
Authors: Hamilton Bruce , Rimmer J. S. , Anderson M. , Leigh D.
Published: December 2004

Confining C60 in the cages within a zeolite (see Figure) results in the modification of the optical properties of the fullerene. This possibly results from a weak interaction of the C60 with the wall of the zeolite which is, however, strong enough to perturb the electronic structure of the C60 resulting in otherwise forbidden transitions (e.g. white light emission) being observed.

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Conducting polymers—materials of commerce
Authors: Miller Joel S.
Published: December 2004

Are conducting polymers commercially viable? In the first part of a two‐part article the attributes of conducting polymers which make them attractive for the development of new products are reviewed. In the second part (next month) products based on conducting polymers will be discussed in detail.
Synthesis and electropolymerization of 3‐(3,3,4,4,5,5,6,6,6‐nonafluorohexyl‐1‐dimethylsilyl thiophene): Reduction of steric hindrance in 3‐substituted poly(thiophenes) by fluorophilic interactions
Authors: Thobie‐Gautier Christine , Guy Alain , Gorgues Alain , Jubault Michel , Roncali Jean
Published: December 2004

Fluoropolymers and conjugated poly(thiophenes) both exhibit exceptional properties: the fluoropolymers are known for their low coefficient of friction, high thermal and chemical stability, hydrophobicity and lipophobicity, while poly(thiophenes) allow the design of tailored conducting polymers. A combination of these properties would be of great interest. The title compound (see Figure) can be readily electropolymerized, yielding a hydrophobic conjugated polymer with doping level and conductivity comparable to those of its alkyl‐substituted analogue.

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Nematic liquid crystalline mineral polymers
Authors: Davidson Patrick , Gabriel Jean‐Christophe , Levelut Anne‐Marie , Batail Patrick
Published: December 2004

Anisotropic fluids are demonstrating that liquid crystals need not be organic. Recent theories predict the existence of lyotropic liquid crystalline phases for particular anisotropies and concentrations of the fluid‐constituting objects, regardless of their chemical nature. Attention has been focused on the solution‐phase chemistry of LiMo3Se3, which dissolves in highly polar solvents to give very long Mo3Se3 strings (the Figure shows a texture photograph of LiMo3Se3 in N‐methylformamide).

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Advanced materials—A tale of two journals
Authors: Gregory Peter
Published: December 2004

Advanced Materials has changed during its first five years of publication. The development of the journal from its beginnings as a section of Angewandte Chemie to today's international and interdisciplinary journal is traced. Trends in the type, number and rate of acceptance of papers are pointed out, along with the increasing variety of their country of origin. Looking towards the future, the members of the new Editorial Advisory Board who will guide the journal in the coming months are introduced.
Nanoporous tin(IV) sulfides: Mode of formation
Authors: Jiang Tong , Ozin Geoffrey A. , Bedard Robert L.
Published: December 2004

Nanoporous R‐SnS‐n materials e.g. (Et4N)2Sn3S7, have been sythesized and characterized. The crystal structures of two molecular tin(IV) sulfide species that are thought to be important in the formation of these materials are reported. Both contain the dimer (Sn2S6)4⊖, which can be combined (see Fingure) to form the Sn4S4 broken‐cube clusters that constitute the open framework of R‐SnS‐1.

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Photoinitiation of vinyl polymerization by polysilanes
Authors: Wolff Andrew R , West Robert
Published: January 2005

Polysilanes were found to photoinitiate the polymerization of a variety of vinyl monomers including methyl methacrylate, styrene, ethyl acrylate and acrylic acid. Polymerization initiated by polysilane photolysis is rather insensitive to oxygen inhibition, which may make it especially suitable for polymerization of thin films. The initiation efficiency of poly(phenylmethylsilylene) in styrene was determined from dilatometry data to be 1 × 10−3. This rather low efficiency is counterbalanced by the very high extinction coefficient of polysilane polymers, ca. 4–8 × 103 per silicon atom. Possible reasons for the low initiation efficiency and reduced oxygen inhibition of polysilane photoinitiators are discussed.