bluuebunny/crossref_metadata_2025 huggingface dataset:
Maps in the Marketplace: Cartographic Vendors and Their Customers in Eighteenth-Century America
Authors: Bosse David
Published: June 2007

The sale and purchase of maps, charts, atlases, and globes in colonial British America and the early United States has received little scholarly attention. Most discussions of the eighteenth-century map trade have concerned activities in Europe or have focused on the production, rather than the consumption, of cartographic products. For much of the eighteenth century, the American map trade consisted of a wide variety of retailers selling more-or-less contemporary English products. But French-, German-, Dutch-, and American-made maps, and the occasional antiquarian map or atlas, could also be found on the market. Ownership of cartographic products has been documented among a diverse group of individuals, ranging from physicians and clergymen to farmers and blacksmiths. Drawing upon sources such as newspaper advertisements, booksellers’ catalogues, correspondence, business accounts, subscription lists, and court documents, this article provides an overview of the American map trade during the period from 1700 to 1800.
A dual extremum principle in thermodynamics
Authors: Mitsos Alexander , Barton Paul I.
Published: June 2007

Phase equilibria of multicomponent mixtures are considered and a reinterpretation of the Gibbs tangent plane stability criterion is proposed via Lagrangian duality. The starting point is the natural primal problem of minimizing the Gibbs free energy subject to material balance. The stable phase split is the solution of the corresponding dual problem, providing a necessary and sufficient dual extremum principle. Only in the absence of duality gap is the physical phase split also the solution of the primal problem. The only requirements are continuity of the Gibbs free energy and the trivial requirement that each species is present in the overall composition. The number of phases is permitted to be infinite, and does not need to be known a priori. No assumption is made on the presence of all species in all phases. Case studies are presented based on the NRTL and UNIQUAC activity coefficient model. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Polyferrocenylsilan‐basierte Polymersysteme
Authors: Bellas Vasilios , Rehahn Matthias
Published: June 2007

Metallopolymere haben sich in den letzten Jahrzehnten zu einem ergiebigen Forschungsgebiet entwickelt. Besonders die Polyferrocenylsilan(PFS)‐Chemie hat sich dabei rasant entwickelt. Nach Entdeckung der thermischen Ringöffnungspolymerisation (ROP) von Sila[1]ferrocenophanen konnten Polyferrocenylsilane bald auch durch anionische, kationische, übergangsmetallkatalysierte und photolytische anionische ROP zugänglich gemacht werden. Hiervon ausgehend wurden unterschiedlichste weiterführende Synthesestrategien ausgearbeitet, die Zugang zu einer breiten Palette an Copolymeren, Polyelektrolyten und nanostrukturierten Materialien eröffnen. Die physikalischen Eigenschaften PFS‐basierter Polymere sowie die mit ihnen realisierbaren Funktionen wurden erforscht und können jetzt in technischen Anwendungen genutzt werden.
Strained Metallocenophanes and Related Organometallic Rings Containing π‐Hydrocarbon Ligands and Transition‐Metal Centers
Authors: Herbert David E. , Mayer Ulrich F. J. , Manners Ian
Published: June 2007

The structures, bonding, and ring‐opening reactions of strained cyclic carbon‐based molecules form a key component of standard textbooks. In contrast, the study of strained organometallic molecules containing transition metals is a much more recent development. A wealth of recent research has revealed fascinating nuances in terms of structure, bonding, and reactivity. Building on initial work on strained ferrocenophanes, a broad range of strained organometallic rings composed of a variety of different metals, π‐hydrocarbon ligands, and bridging elements has now been developed. Such strained species can potentially undergo ring‐opening reactions to functionalize surfaces and ring‐opening polymerization to form easily processed metallopolymers with properties determined by the presence of the metal and spacer. This Review summarizes the current state of knowledge on the preparation, structural characterization, electronic structure, and reactivity of strained organometallic rings with π‐hydrocarbon ligands and d‐block metals.
Synthesis of bis‐N‐acyllactams type chain extenders for polyesters and polyamides
Authors: Stier Ulli , Schweizer Michael
Published: June 2007

This article shows the synthesis of chain extenders derived from the group of bis‐N‐acyllactams. These chain extenders may not only increase the molecular weight of polyesters or polyamides but also permit a flexible modification at the same time by incorporating an arbitrary functionality in the polymer chains. The chain extenders are synthesized by a two step process starting from terephthaloyl chloride, ε‐caprolactam, and the functional moiety R which derives from a diol HOROH or diamine H2NRNH2. For five chain extenders varying in the moiety R, the synthesis is explicitly shown and the thermal stability is investigated. It can be shown that the chain extenders are thermal stable up to 260°C at least. The chain extenders may thus be useful to increase the molecular weight and to modify many important thermoplastic polyesters and polyamides during the melt extrusion process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
An HPLC method for the determination of the free cortisol/cortisone ratio in human urine
Authors: Sharef O. Al , Feely J. , Kavanagh P. V. , Scott K. R. , Sharma S. C.
Published: June 2007

The measurement of the urinary free cortisol–cortisone ratio has been reported to be a sensitive indicator of renal 11 β‐hydroxysteroid dehydrogenase type 2 (11 β‐HSD 2) activity. This converts biologically active cortisol to inactive cortisone. A decrease in its activity (e.g. through disease or inhibition caused by a therapeutic agent or a foodstuff) may increase cortisol levels and susceptibility towards hypertension. The method presented here uses a simple isocratic tandem column HPLC system. The method has been validated and found to be robust and reproducible. The lower limit of quantification (LLOQ) was found to be 10 ng/mL for both cortisol and cortisone. Samples of urine (n = 99) from patients, most of whom were on complex combinations of drugs, were analyzed and 92% of samples were found to give successful results with this method (cortisol and cortisone above LLOQ). The ratio ranged from 0.07 to 5.61. No interferences were noted from the drugs that the patients were taking. It was also found that a morning spot urine sample gave comparable results to 24 h collection samples, thus making sample collection much easier. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of benzofurazan derivatization reagents for carboxylic acids in liquid chromatography/electrospray ionization–tandem mass spectrometry
Authors: Santa Tomofumi , Al‐Dirbashi Osama Y , Ichibangase Tomoko , Fukushima Takeshi , Rashed Mohamed S , Funatsu Takashi , Imai Kazuhiro
Published: June 2007

The applicability of benzofurazan derivatization regents to carboxylic acids analysis in LC/ESI‐MS/MS (high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry) was examined. The product ion spectra of DAABD‐AE {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐(2‐aminoethylamino)‐2,1,3‐benzoxadiazole}, DAABD‐PZ {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐N‐piperazino‐2,1,3‐benzoxadiazole}, DAABD‐PiCZ {4‐[4‐carbazoylpiperidin‐1‐yl]‐7‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐2,1,3‐benzoxadiazole}, DAABD‐ProCZ {4‐[2‐carbazoylpyrrolidin‐1‐yl]‐7‐[2‐(N,N‐dimethylamino) ethylaminosulfonyl]‐2,1,3‐benzoxadiazole} and DAABD‐Apy {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐(3‐aminopyrrolidin‐1‐yl)‐2,1,3‐benzoxadiazole}, and their acetylated compounds were obtained. An intense fragment ion at m/z 151 corresponding to (dimethylamino)ethylaminosulfonyl moiety was observed in each spectra, suggesting that these reagents were suitable for ESI‐MS/MS analysis. DAABD‐AE, DAABD‐APy and DAABD‐PZ were applied to the analysis of octanoic acid and it was found that DAABD‐AE and DAABD‐APy gave high signal intensity suitable for LC/ESI‐MS/MS. Copyright © 2007 John Wiley & Sons, Ltd.
Peptaibiotics and Peptaibols: An Alternative to Classical Antibiotics?
Authors: Duclohier Hervé
Published: June 2007

The development and antimicrobial properties of peptaibiotics and peptaibols are discussed. Also, the role of emerging peptaibol analogues, of alamethicin, e.g., harzianins HC, trichotoxin, and antiamoebin, is outlined.
Peptaibols: Stable Markers of Fungal Development in the Marine Environment
Authors: Poirier Laurence , Montagu Monique , Landreau Anne , Mohamed‐Benkada Mustapha , Grovel Olivier , Sallenave‐Namont Claire , Biard Jean‐François , Amiard‐Triquet Claude , Amiard Jean‐Claude , Pouchus Yves François
Published: June 2007

Different peptaibols were observed in both fresh and frozen marine sediments collected from a marine area devoted to bivalve culture (Fier d'Ars, Atlantic coast, France). The identification of the peptaibols was based on a three‐step mass‐spectrometric analysis: observation of doubly charged ions with a characteristic isotopic profile, cleavage and observation of C‐ and N‐terminal fragments, and partial sequencing of the N‐terminal segments. The MS characteristics indicated numerous similarities between the peptaibols detected and those produced by different strains of Trichoderma species isolated from fresh sediments. Peptaibols were also detected in mussel samples collected at the same site. This constitutes the first observation of contamination of the marine human‐food chain by fungal metabolites. Since peptaibols were readily observed both in fresh sediments and in samples kept frozen for several years, these compounds can be considered as stable markers of the development of Trichoderma in the marine environment.
The ‘Azirine/Oxazolone Method’ in Peptaibol Synthesis: Preparation of a Derivative of Trichotoxin A‐50 (G)
Authors: Altherr Werner , Linden Anthony , Heimgartner Heinz
Published: June 2007

The synthesis of a mixture of epimeric derivatives of the peptaibol trichotoxin A‐50 (G) is described. The ‘azirine/oxazolone method’ has been used as a superior method for the introduction of the Aib as well as the Iva units into the peptide chain. In this protocol, 2,2‐disubstituted 2H‐azirin‐3‐amines are the synthons for 2,2‐disubstituted glycines, which undergo coupling with N‐protected amino or peptide acids in high yield, and without any need of coupling reagents. The problem of the instability of the amide function of the Gln side chain under the conditions of the acid‐catalyzed hydrolysis of Z‐Gln‐(Aib)n‐N(Me)Ph was solved by using an appropriate protecting group for the amide function of the Gln side chain, e.g., the triphenylmethyl (trityl; Tr) group. The structures of two intermediate peptides, i.e., the segments comprising residues 1–5 and 10–13, resp., were established by X‐ray crystallography.
Multinuclear Solid‐State‐NMR and FT‐IR‐Absorption Investigations on Lipid/Trichogin Bilayers
Authors: Heuber Christiane , Formaggio Fernando , Baldini Chiara , Toniolo Claudio , Müller Klaus
Published: June 2007

Solid‐state NMR and FT‐IR absorption spectroscopy are employed to study the molecular properties of 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (DMPC) lipids as a function of trichogin‐OMe content, a membrane‐active analogue of the peptaibol trichogin GA IV. Variable‐temperature NMR studies are performed, comprising 13C‐, 31P‐, and 14N‐NMR line‐shape and relaxation experiments, to provide information about the mobility and ordering of the phospholipid head group and the acyl‐chain region in the absence and presence of trichogin‐OMe. Likewise, variable‐temperature FT‐IR‐absorption studies are performed, and the conformation‐sensitive CH2 stretching bands are analyzed to examine the conformational state of the acyl chain.

At lower trichogin‐OMe concentrations, the peptide exhibits no remarkable influence on the dynamics and ordering features of the phospholipid molecules. It is concluded that, in this case, trichogin‐OMe is embedded in the lipid bilayer, with its helix axis laying parallel to the bilayer plane, the more hydrophobic part pointing towards the inner part of the bilayer (‘carpet‐like’ superstructure). The lipid dynamics are probed by rotating‐frame spin–lattice‐relaxation (T1ρ) experiments for the 13C and 31P nuclei, which are assumed to be dominated by collective‐order fluctuations. Variation of T1ρ with sample composition is attributed to changes of the membrane stiffness.

For the sample with the highest lipid/peptide (L/P) molar ratio, i.e., L/P 5 : 1, phase separation as a result of membrane disruption occurs. In this case, a second spectroscopic component can be separated in the 31P‐NMR spectra. In addition, the (motionally averaged) magnetic interactions are greatly reduced, the actual values differing for both components. The second spectroscopic component refers to membrane components with high trichogin‐OMe concentration and to strong lipid–trichogin‐OMe interactions, as reflected by significant changes of the head‐group orientation (toroidal model). At the same time, DMPC molecules exist with minor lipid–trichogin‐OMe interactions, most probably in smaller liposomes, trichogin‐OMe being embedded in a ‘carpet‐like’ manner. Moreover, lipid ordering is generally reduced for the highly concentrated sample, which may result from fast lateral lipid motion along the curved bilayer surface.
Antiamoebin I in Methanol Solution: Rapid Exchange between Right‐Handed and Left‐Handed 310‐Helical Conformations
Authors: Shenkarev Zakhar O. , Paramonov Alexander S. , Nadezhdin Kirill D. , Bocharov Eduard V. , Kudelina Irina A. , Skladnev Dmitry A. , Tagaev Andrey A. , Yakimenko Zoya A. , Ovchinnikova Tatiana V. , Arseniev Alexander S.
Published: June 2007

Antiamoebin I (Aam‐I) is a membrane‐active peptaibol antibiotic isolated from fungal species belonging to the genera Cephalosporium, Emericellopsis, Gliocladium, and Stilbella. Antiamoebin I has the amino acid sequence: Ac‐Phe1‐Aib‐Aib‐Aib‐Iva‐Gly‐Leu‐Aib8‐Aib‐Hyp‐Gln‐Iva‐Hyp‐Aib‐Pro‐Phl16. By using the uniformly 13C,15N‐labeled sample of Aam‐I, the set of conformationally dependent J couplings and 3hJNC couplings through H‐bonds were measured. Analysis of these data along with the data on magnetic nonequivalence of the 13Cβ nuclei (Δδ(13Cβ)) in Aib and Iva residues allowed us to draw the univocal conclusion that the N‐terminal part (Phe1–Gly6) of Aam‐I in MeOH solution is in fast exchange between the right‐handed and left‐handed 310‐helical conformations, with an approximately equal population of both states. An additional conformational exchange process was found at the Aib8 residue. The 15N‐NMR‐relaxation and CD‐spectroscopy measurements confirmed these findings. Molecular modeling and Monte Carlo simulations revealed that both exchange processes are correlated and coupled with significant hinge‐bending motions around the Aib8 residue. Our results explain relatively low activity of Aam‐I with respect to other 15‐amino acid residue peptaibols (for example, zervamicin) in functional and biological tests. The high dynamic ‘propensity’ possibly prevents both initial binding of the antiamoebin to the membrane and subsequent formation of stable ionic channels according to the barrel‐stave mechanism.
Solvent Effects on the Secondary Structure of the Membrane‐Active Zervamicin Determined by PELDOR Spectroscopy
Authors: Milov Alexander D. , Tsvetkov Yuri D. , Gorbunova Elena Y. , Mustaeva Leyla G. , Ovchinnikova Tatiana V. , Handgraaf Jan‐Willem , Raap Jan
Published: June 2007

Zervamicin is a voltage‐gated ion‐channel‐forming peptide. Channels are generally considered to be formed by first insertion of amphipathic molecules into the phospholipid bilayer, followed by self‐assembly of a variable number of transmembrane helices. We have studied the length of the peptide structure to address the question whether this peptide is long enough to span the phospholipid bilayer. The pulsed electron‐electron double resonance (PELDOR) spectroscopic technique was used to determine the length of the helical molecule in membrane‐mimicking solvents. This was achieved from the distance‐related dipole–dipole interaction between spin labels, which were located at both ends of the linear peptide chain. The data were obtained by using samples of frozen glassy solutions of MeOH, MeOH/toluene, and MeOH/CHCl3. Contributions of inter‐ and intramolecular interactions of spin labels were separated to analyze the intramolecular interaction and the distance distribution function between the labels. It is shown that the main maximum of the distribution functions is located at a distance of ca. 3.3 nm, and this distance appears to be only slightly dependent on the solvent composition. The distribution function was observed to narrow after addition of either CHCl3 or toluene to MeOH. This effect is rationalized in terms of a decreased mobility of the terminal amino acid residues. By molecular‐dynamics simulations, it was shown that the conformation, corresponding with the predominant distance found by PELDOR, agrees well with the mixed α/310‐helical that was previously determined by NMR. However, in the case toluene was added to the MeOH solution to further increase the hydrophobicity of the environment of the membrane‐active peptide, the distribution function gives rise to a minor fraction (7–8%) with a distance of 4.2 nm. This distance corresponds most likely to the more extended 27‐helix structure.
Alamethicin Interaction with Lipid Membranes: A Spectroscopic Study on Synthetic Analogues
Authors: Stella Lorenzo , Burattini Marcello , Mazzuca Claudia , Palleschi Antonio , Venanzi Mariano , Coin Irene , Peggion Cristina , Toniolo Claudio , Pispisa Basilio
Published: June 2007

Alamethicin (Alm) is one of the most extensively studied membrane‐active antibiotic peptides, but several aspects of its mechanism of action are still under debate. In this study, synthetic analogues of natural Alm F50/5 (Alm‐N), labeled with a 9H‐fluoren‐9‐yl group at the N‐ (F‐Alm) or C‐terminus (Alm‐F), were employed to investigate the position and orientation of this peptide in the membrane environment. Depth‐dependent fluorescence quenching and polarized ATR‐FT‐IR experiments demonstrated that, in the absence of a transmembrane potential, Alm inserts its N‐terminus into the membrane, while the C‐terminus is exposed to the outer aqueous phase. We also found that the peptaibol populates different orientations with respect to the membrane normal. Furthermore, fluorescence resonance‐energy transfer (FRET) indicated that no peptide translocation to the inner leaflet of lipid bilayers occurs. The mechanism of action of Alm is discussed on the basis of these findings.

Two other Alm analogues, Alm‐P and Alm‐S, were exploited to investigate the role of specific Alm residues in terms of membrane‐perturbing activity. Substitution of two or three Gln (E) residues (the only polar amino acids in the alamethicin sequence) by γ‐methyl glutamate (Glu(OMe)) residues induced marked variations in the aggregation and partition behaviors of the peptaibols, which, in turn, modulate their membrane activity. In particular, substitution of Gln18 and Gln19 caused a six‐fold increase in membrane‐perturbing activity, thus demonstrating that these residues are not essential for the stabilization of Alm pores.
Channel‐Forming Activity of Alamethicin: Effects of Covalent Tethering
Authors: Woolley G. Andrew
Published: June 2007

In this short review article, the effects of covalent tethering of alamethicin molecules on channel‐forming behavior are described. Broadly speaking, these chemical modifications have provided insight into all three aspects of channel behavior: the structure of the conducting state, the ion‐selectivity and ion‐permeation properties, and the voltage dependence. Each of these aspects are discussed in turn.
Membrane Permeabilization of a Mammalian Neuroendocrine Cell Type (PC12) by the Channel‐Forming Peptides Zervamicin, Alamethicin, and Gramicidin
Authors: Weidema Adam F. , Kropacheva Tatyana N. , Raap Jan , Ypey Dirk L.
Published: June 2007

Zervamicin IIB (ZER) is a 16‐mer peptaibol that produces voltage‐dependent conductances in artificial membranes, a property considered responsible for its antimicrobial activity to mainly Gram‐positive microorganisms. In addition, ZER appears to inhibit the locomotor activity of the mouse (see elsewhere in this Issue), probably by affecting the brain. To examine whether the electrophysiological properties of the neuronal cells of the central neural system might be possibly influenced by the pore forming ZER, the present study was undertaken as a first attempt to unravel the molecular mechanism of this biological activity. To this end, membrane permeabilization of the neuron‐like rat pheochromocytoma cell (PC12) by the channel‐forming ZER was studied with the whole‐cell patch‐clamp technique, and compared with the permeabilizations of the well‐known voltage‐gated peptaibol alamethicin F50/5 (ALA) and the cation channel‐forming peptide‐antibiotic gramicidin D (GRAM). While 1 μM GRAM addition to PC12 cells kept at a membrane potential Vm=0 mV causes an undelayed gradual increase of a leak conductance with a negative reversal potential of ca. −24 mV, ZER and ALA are ineffective at that concentration and potential. However, if ZER and ALA are added in 5–10 μM concentrations while Vm is kept at −60 mV, they cause a sudden and strong permeabilization of the PC12 cell membrane after a delay of 1–2 min, usually leading to disintegrating morphology changes of the patched cell but not of the surrounding cells of the culture at that time scale. The zero reversal potential of the established conductance is consistent with the known aselectivity of the channels formed. This sudden permeabilization does not occur within 10–20 min at Vm=0 mV, in accordance with the known voltage dependency of ZER and ALA channel formation in artificial lipid membranes. The permeabilizing action of these peptaibols on the culture as a whole is further supported by K+‐release measurements from a PC12 suspension with a K+‐selective electrode. Further analysis suggested that the permeabilizing action is associated with extra‐ or intracellular calcium effects, because barium inhibited the permeabilizing effects of ZER and ALA. We conclude, for the membrane of the mammalian neuron‐like PC12 cell, that the permeabilizing effects of the peptides ZER and ALA are different from those of GRAM, consistent with earlier studies of these peptides in other (artificial) membrane systems. They are increased by cis‐positive membrane potentials in the physiological range and may include calcium entry into the PC12 cell.
The Peptaibol Alamethicin Induces an rRNA‐Cleavage‐Associated Death in Arabidopsis thaliana
Authors: Rippa Sonia , Adenier Hervé , Derbaly Michel , Béven Laure
Published: June 2007

The plant‐metabolic response to amphipathic peptides produced by the soil fungi of the genus Trichoderma remains largely unknown. The present investigation was undertaken to examine the death process in alamethicin‐treated Arabidopsis thaliana plantlets. The rapid death triggered by alamethicin (at 50 μM) was shown to be associated with protein‐synthesis arrest and with specific cleavage of 18S and 25S ribosomal RNA. The use of an inhibitor of nitric oxide (NO) synthases and of an NO scavenger suggested that rRNA cleavage was suppressed by NO. Experiments conducted with a synthetic alamethicin analogue, in which all α‐aminoisobutyric acid (Aib) residues have been replaced by leucine moieties, showed that the non‐coded residues are essential for the ability of the peptaibol to induce rRNA cleavage in Arabidopsis. Our data indicate that further investigations on the mode of action of alamethicin in planta could be of great interest to study the death‐signaling pathway associated with rRNA degradation in plants.
Neuroleptic Properties of the Ion‐Channel‐Forming Peptaibol Zervamicin: Locomotor Activity and Behavioral Effects
Authors: Ovchinnikova Tatiana V. , Levitskaya Natalia G. , Voskresenskaya Olga G. , Yakimenko Zoya A. , Tagaev Andrey A. , Ovchinnikova Anastasia Y. , Murashev Arkadiy N. , Kamenskii Andrey A.
Published: June 2007

Zervamicins IIA and IIB are members of the peptaibol family of peptide antibiotics. They are produced by the fungus Emericellopsis salmosynnemata. Peptaibols are known to be of potential usefulness for chemotherapeutic applications, as are other secondary fungal metabolites. Previously, we have found zervamicins to decrease spontaneous locomotor activity in mice, suggesting their neurotropic properties on an equal footing with antimicrobial activity. The current study deals with behavioral effects of zervamicins IIA and IIB in mice. According to our results, both zervamicins induce a reliable decrease in locomotion and exploratory activity measured in the hole‐board test. The behavioral effects of zervamicin IIA become apparent at lower dosages (0.05–2.0 mg/kg) as compared with zervamicin IIB (0.5–12.0 mg/kg). The experiments on behavioral effects in the elevated plus maze test showed that both zervamicins caused a reliable decrease in the number of head‐dippings, open‐arm entries, and rearings. The observed behavioral effects may be rather associated with a decrease in the exploratory activity than with anxiety‐related responses in mice. Zervamicins induced depression‐like behavior of experimental animals in the forced‐swim test. Both peptaibols reduce physical endurance and change motor coordination of experimental animals in the bar‐holding test. Taken together, the data obtained clearly indicate that both zervamicins possess neuroleptic activity.
Gadofullerenes as nanoscale magnetic labels for cellular MRI
Authors: Sitharaman Balaji , Tran Lesa A. , Pham Quynh P. , Bolskar Robert D. , Muthupillai Raja , Flamm Scott D. , Mikos Antonios G. , Wilson Lon J.
Published: June 2007

In this study, anionic gadofullerene {Gd@C60[C(COOH)2]10} was used as an in vitro cellular magnetic resonance imaging label. The cellular uptake characteristics of this gadofullerene were significant and nonspecific, and excellent labeling efficiency (98–100%) was achieved without a transfecting agent. The average uptake was up to 133.6 ± 5.5 pg Gd per cell or 1011 Gd3+ ions per cell. The difference in the longitudinal relaxation time T1 between labeled and unlabeled cells generated good contrast between labeled and unlabeled cells. A clinical magnetic resonance imaging imager at 1.5 T showed that signal intensity on the T1 weighted magnetic resonance images was 250% greater in labeled cells. Thus, the anionic gadofullerene {Gd@C60[C(COOH)2]10} is an attractive candidate for ex vivo labeling and noninvasive in vivo tracking of any mammalian cell via magnetic resonance imaging. Copyright © 2007 John Wiley & Sons, Ltd.
Thermal properties of a Nd:LuVO4 crystal
Authors: Ran Donggang , Xia Hairui , Sun Shangqian , Liu Fengqin , Ling Zongcheng , Ge Wenwei , Zhang Huaijin , Wang Jiyang
Published: June 2007

A Nd‐doped lutetium orthovanadate Nd:LuVO4 crystal has been grown using a modified Czochralski method. The thermal properties of this crystal have been studied by measuring the thermal expansion, specific heat and thermal diffusivity. The thermal expansion coefficients are α11 = 1.7 × 10‐6, α22 = 1.5 × 10‐6 and α33 = 9.1 × 10‐6/K in the temperature range of 298–573 K along the three respective crystallographic axes. The specific heat is almost linear and increases from 0.442 to 0.498 Jg‐1K‐1 in the measured temperature range. The thermal diffusivity is anisotropic and decreases with increasing temperature from 295 to 548 K. At room temperature the calculated thermal conductivities κ11 and κ33 are 7.96 and 9.77 Wm‐1K‐1, respectively. These thermal parameters of Nd:LuVO4 crystal have indicated that it is an excellent candidate laser material. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural, optical and photoluminescence properties of ZnS: Cu nanoparticle thin films as a function of dopant concentration and quantum confinement effect
Authors: Jayanthi K. , Chawla S. , Chander H. , Haranath D.
Published: June 2007

Thin films of ZnS: Cu nanoparticles were deposited in chemical bath by a pH controlled solution synthesis technique. The copper concentration was varied from 0 to 0.1M%. XRD and SEM indicated variations in diffracted intensity and morphology with Cu concentration. The PL spectrum of the undoped ZnS nanoparticles showed emission peaks at 393 and 432nm that could be attributed to the intrinsic defect states of ZnS nanoparticles. For ZnS: Cu samples three peaks in the range of 390nm, 480nm and 525nm were observed. With increase in Cu concentration from 0.001 to 0.1M%, the peak position of 480nm and 525nm did not change, whereas 390nm peak red shifted to longer wavelength region to 422nm. In addition, it was found that the overall photoluminescence intensity reached maximum at 0.01M% and quenched with further increase in Cu concentration. Enhancement of blue and green light emission by seven and twenty fivefold respectively compared to undoped ZnS was observed in ZnS: Cu with optimal dopant concentration. Time resolved decay of photoluminescence showed faster decay for 390 – 420nm purple/ blue emission compared to green (525nm) Cu related emission which is in the microsecond time scale. Optical absorption measurements indicate enhancement of band gap (3.89eV) for undoped ZnS suggesting the quantum confinement effect in the developed nanoparticles of size below the Bohr diameter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cover Picture: Expansion and activation of CD4+CD25+ regulatory T cells in Heligmosomoides polygyrus infection – Eur. J. Immunol. 7/2007
Authors: Finney Constance A. M. , Taylor Matthew D. , Wilson Mark S. , Maizels Rick M.
Published: June 2007

The cover shows a photograph of an individual adult Heligmosomoides polygyrus, a gastrointestinal nematode parasite and was provided by Finney et al. (pp. 1874–1886). In this study authors analyse in detail the development and phenotype (CTLA‐4, GITR, CD103) of cells responsible for the suppression of the early Th2 responses during murine H. polygyrus infection. Both CD25+Foxp3+ and CD25+Foxp3‐ subsets are increased during infection but, interestingly, only the latter display significant increases in TGF‐β levels.
Synthesis and Characterization of CuII Complexes with Amino Acid Substituted Di(2‐pyridyl)amine Ligands
Authors: Kirin Srećko I. , Yennawar Hemant P. , Williams Mary Elizabeth
Published: June 2007

The two‐step syntheses of the substituted di(2‐pyridyl)amine ligands (dpa), dpa‐CH2CO2H (1) and dpa‐PhCO2H (2), are described. Ligands 1 and 2 are successfully coupled to the amino acid phenylalanine, yielding the derivatives 4 and 6, respectively. Four CuII(dpa)2 complexes, [Cu(dpa‐CH2CO2tBu)2(NO3)2] (3Cu), [Cu(dpa‐CH2CO‐PheOMe)2(H2O)2](NO3)2·2MeOH (4Cu), [Cu(dpa‐PhCO2Me)2 (MeOH)2](ClO4)2 (5Cu) and [Cu(dpa‐PhCO‐PheOMe)2(ClO4)2] (6Cu) have been prepared and characterized, including their single crystal X‐ray structures. Fluorescence emission at UV (for 3 and 4) or blue (for 5 and 6) wavelengths of the free ligands is preserved in the corresponding Cu complexes, although with lower intensity. X‐band EPR spectra of 4Cu and 6Cu both revealed one axial CuII signal with hyperfine and superhyperfine splittings. Complexes 4Cu and 6Cu are chiral inorganic complexes with amino acid bioconjugates that may serve as nucleoside analogs in modified peptide nucleic acids (PNA). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Classification of feeding fats by FT‐IR spectroscopy
Authors: Gasperini Gianmaria , Fusari Elena , Della Bella Laura , Bondioli Paolo
Published: June 2007

In this paper, a technique useful for the classification of different food oil co‐ and by‐products of potential use for feed preparation is shown. The proposal is based upon a Fourier transform infrared evaluation of different classes of compounds, and its elaboration was carried out starting from the knowledge of the chemical composition of each feedstock category. Using this technique, a sure classification of fatty acid calcium soaps, fully hydrogenated fatty acids, lecithins, acid oils from chemical refining, acid oils from physical refining and fish oils can be easily done. The remaining categories of animal fats, fried oils and oils recovered from exhausted bleaching earth can be differentiated by using one or two additional chemical tests. The scope of this paper is to provide a quick, easy and non‐expensive tool for a correct classification of feedstock, in order to allow the choice of correct and applicable analytical tests for the evaluation of the quality and of the composition of each sample.
Inhibition of butter oxidation by some phenolics
Authors: Soulti Kalliopi , Roussis Ioannis G.
Published: June 2007

The ability of some phenolic compounds to inhibit butter oxidation was evaluated. Peroxide values and thiobarbituric acid reactive substances were monitored during storage of butter at 50 °C and at 110 °C. Gallic acid, caffeic acid and catechin, each at 80 mg/L, inhibited butter oxidation at 50 °C to a degree equal to that of butylated hydroxyanisole (BHA) at 200 mg/L. Gallic acid, at 80 mg/L, was more effective than BHA, at 200 mg/L, in inhibiting butter oxidation at 110 °C. Present results indicate that some phenolics, and especially gallic acid, may be taken into account as antioxidants in butter.
Reductive Coupling of Aromatic Aldehydes Promoted by an Aqueous TiCl3/tBuOOH System in Alcoholic Cosolvents
Authors: Clerici Angelo , Greco Cosimina , Panzeri Walter , Pastori Nadia , Punta Carlo , Porta Ombretta
Published: June 2007

The tert‐butoxyl radical, generated by the aqueous TiIII/TBHP system, abstracts an H atom from alcoholic cosolvents (EtOH, iPrOH), leading to α‐hydroxyalkyl radicals thatreduce aromatic aldehydes to the corresponding 1,2‐diols. The reactivities observed are explained by resonance stabilization of the α‐hydroxybenzyl radicals formed in the electron‐transfer (ET) process. Good Hammett‐type correlations are obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cover Picture: Progress in Supramolecular Chemistry of Gases (Eur. J. Org. Chem. 20/2007)
Authors: Rudkevich Dmitry M.
Published: June 2007

The cover picture shows a star field filled with molecules of environmentally important gases. Gases are very interesting for molecular recognition. Supramolecular complexes with gases have been obtained by utilizing dynamic, reversible forces. On this basis, supramolecular, optical sensors for the detection of gases have been introduced. Studies on molecules and molecular materials for gas entrapment, separation, storage and release that involve synthetic containers, self‐assembling capsules and even nanotubes and fullerenes have been well in progress. Moreover, supramolecular fixation of gases has yielded stable and selective chemical reagents for preparative organic chemistry. Gases have also been used as building blocks for supramolecular nanostructures. Dynamic, switchable polymers that can be used as storing and separating materials have been constructed from gases. The current progress in supramolecular chemistry and molecular recognition of gases is presented in the Microreview by D. M. Rudkevich on p. 3255 ff. The star field picture is a courtesy of Joe Eakin, Director, The Planetarium at The University of Texas at Arlington.
The uniform estimation of the M/G/1 processor sharing response time distribution
Authors: Hartmann Harro L.
Published: June 2007

This contribution avoids frequently used transform and inversion problems by a decomposition of the transition state model in the original domain. First, the relevant differential‐recurrence backward equation system valid for the M/M/1 processor sharing (PS) is converted to a sum of a service component and an arrival–departure component. The first one yields a pure differential equation system, which can be solved exactly and proves to be uniformly valid for M/G/1 PS systems. The second component vanishes for small and large processor utilisations but contributes to shorter response times otherwise. Thus, the PS service component defines an estimate of the true response time distribution. Second, the higher order moments of the estimates form simple upper bounds of their true much more complicated counterparts where the first moments agree. Partly simulative case studies subject to M, D, H2, heavy‐tailed service time distributions, and PS with permanent customers confirm the new estimation. Third, reference values of the arrival–departure component provide an approximate solution of the differential‐recurrence equation system. This significantly improves the accuracy of the estimates for moderate utilisations. Finally it is shown that the remaining inaccuracies of the estimates are far below expectable forecast errors for high economic loads and otherwise the approximation significantly supports PS system engineering for moderate loads too. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of optically active γ‐lactones via lipase‐catalyzed resolution
Authors: Shimotori Yasutaka , Nakahachi Yukihiko , Inoue Keita , Miyakoshi Tetsuo
Published: June 2007

Both enantiomers of the six major kinds of γ‐lactones were synthesized to >98% e.e. in four steps, starting from succinic anhydride. The key features were the syntheses of the various rac‐N‐methyl‐4‐hydroxyalkanamides via Grignard reaction and the enantioselective acetylation and hydrolysis promoted by Novozym 435. Copyright © 2007 John Wiley & Sons, Ltd.
Mobilizing a region in crisis to build a college‐going culture
Authors: Carden Allen
Published: June 2007

A consortium in California's Central Valley is putting traditional boundaries and thinking aside to attack a low college attainment rate that threatens to limit the future of the poorest and fastest‐growing region of the state.
Leveraging resources to create comprehensive access services
Authors: Boisvert Pamela K.
Published: June 2007

The Colleges of Worcester Consortium has experienced significant success with a partnering model of providing higher education access services across the state of Massachusetts.
From Baccalaureate to the professoriate: Cooperating to increase access to graduate education
Authors: Allen Barbara McFadden , Zepeda Yolanda
Published: June 2007

Faculty in the Summer Research Opportunities Program mentor and prepare students for graduate school.
Structure‐Based Design and Synthesis of the First Weak Non‐Phosphate Inhibitors for IspF, an Enzyme in the Non‐Mevalonate Pathway of Isoprenoid Biosynthesis
Authors: Baumgartner Corinne , Eberle Christian , Diederich François , Lauw Susan , Rohdich Felix , Eisenreich Wolfgang , Bacher Adelbert
Published: June 2007

In this paper, we describe the structure‐based design, synthesis, and biological evaluation of cytosine derivatives and analogues that inhibit IspF, an enzyme in the non‐mevalonate pathway of isoprenoid biosynthesis. This pathway is responsible for the biosynthesis of the C5 precursors to isoprenoids, isopentenyl diphosphate (IPP, 1) and dimethylallyl diphosphate (DMAPP, 2; Scheme 1). The non‐mevalonate pathway is the sole source for 1 and 2 in the protozoan Plasmodium parasites. Since mammals exclusively utilize the alternative mevalonate pathway, the enzymes of the non‐mevalonate pathway have been identified as attractive new drug targets in the fight against malaria. Based on computer modeling (cf. Figs. 2 and 3), new cytosine derivatives and analogues (Fig. 1) were selected as potential drug‐like inhibitors of IspF protein, and synthesized (Schemes 2–5). Determination of the enzyme activity by 13C‐NMR spectroscopy in the presence of the new ligands showed inhibitory activities for some of the prepared cytosine and pyridine‐2,5‐diamine derivatives in the upper micromolar range (IC50 values; Table). The data suggest that it is possible to inhibit IspF protein without binding to the polar diphosphate binding site and the side chain of Asp56′, which interacts with the ribose moiety of the substrate and substrate analogues. Furthermore, a new spacious sub‐pocket was discovered which accommodates aromatic spacers between cytosine derivatives or analogues (binding to ‘Pocket III’) and rings that occupy the flexible hydrophobic region of ‘Pocket II’. The proposed binding mode remains to be further validated by X‐ray crystallography.
Reaction Mechanism of Selenate(IV) Ions with Several Thiols in Aqueous Media
Authors: Forastiere Daniel O. , Borghi Elena B. , Morando Pedro J.
Published: June 2007

In several enzymatic systems, selenium (an essential element commonly incorporated as sodium selenite to the human diet) is bonded through a mercapto group of a cysteine residue. The reaction of SeIV (as selenite) with different thiols in aqueous media was studied to increase the information about the mechanism of the enzyme reaction. The influence of the reagents' concentration on the reaction rate and temporal spectral changes was analyzed. A complex with a UV maximum between 270 and 290 nm was formed, which quickly decayed when the thiol concentration was increased. The proposed reaction mechanism includes a fast SeIV–thiol association step followed by two parallel steps (one is first‐order in the complex and the other one is globally second‐order). Kinetics and equilibrium constants were obtained, and the rate dependence of the thiol oxidation on the SeIV concentration was modelled for all thiols tested. Very good agreement between the experimental and calculated curves was observed.
Habaenines A and B, Two New Norditerpenoid Alkaloids from Aconitum habaense
Authors: Yang Shu , Yang Xiao‐Dong , Zhao Jing‐Feng , Zhang Hong‐Bin , Li Liang
Published: June 2007

Two new norditerpenoid alkaloids, habaenine A and B (1 and 2), together with two known compounds, were isolated from Aconitum habaense. The structures of the new compounds were elucidated on the basis of spectral analyses as (1α,6α,16β)‐8‐(acetyloxy)‐20‐ethyl‐13‐hydroxy‐1,6,16‐trimethoxy‐4‐(methoxymethyl)‐19‐oxoaconitan‐14‐yl 4‐methoxybenzoate (1) and (1α,6α,16β)‐8‐(acetyloxy)‐13‐hydroxy‐1,6,16‐trimethoxy‐4‐(methoxymethyl)‐aconitan‐14‐yl 4‐methoxybenzoate (2).
Superacid‐Catalyzed Cyclization of Methyl (6Z)‐Geranylfarnesoates
Authors: Grinco Marina , Kulciţki Veaceslav , Ungur Nicon , Jankowski Wieslaw , Chojnacki Tadeusz , Vlad Pavel F.
Published: June 2007

Methyl (2Z,6Z,10E,14E)‐ (3) and methyl (2E,6Z,10E,14E)‐geranylfarnesoate (4) were prepared, and then individually cyclized in the presence of the superacid FSO3H. In the case of substrate 3, the scalaranic ester 9 (26%) and the cheilanthanic ester 10 (39%) were isolated. Under the same conditions, substrate 4 afforded a mixture of the corresponding stereoisomers 11 (25%) and 12 (63%). The observed product selectivity supports that the internal, (6Z)‐configured CC bond in these and other biologically relevant substrates plays an essential role in the cyclization process.
New Labdane‐Type Diterpenoids from Amentotaxus argotaenia
Authors: Yang Qin , Ye Guan , Feng Jia‐Quan , Zhao Wei‐Min
Published: June 2007

A new labdane diterpene, amentotaxin A (1), and an unprecedented dinorlabdane diterpene, amentotaxin B (2), were isolated from the stems of Amentotaxus argotaenia (Hance) Pilger, together with seven known compounds. Their structures were identified by in‐depth spectroscopic and mass‐spectrometric analyses.
Two New Triterpene Lactones from the Stems of Kadsura polysperma
Authors: Jia Zhengwei , Lu Yan , Liao Zhixin , Chen Daofeng
Published: June 2007

Two new triterpene lactones, polysperlactones A (2) and B (3), were isolated from the stems of Kadsura polysperma, together with the known compounds heteroclitalactone D (1) and schisanlactone E (4). Their structures were elucidated by spectroscopic methods, including 2D‐NMR and HR‐MS techniques. The configuration of 1 was confirmed by X‐ray analysis. Compounds 2 and 3 are members of a rare class of 3,4‐secolanostane metabolites with ring‐expanded or cyclized structures, respectively.
Young mothers' play with their toddlers: individual variability as a function of psychosocial factors
Authors: Driscoll Joan Riley , Easterbrooks M. Ann
Published: June 2007

There is no one style of parenting which characterizes young mothers as a group. In addition, life circumstances play an important role in shaping maternal behaviour. The aim of this study was to identify patterns of maternal play behaviour and contextual (social and personal) factors associated with these different patterns. In this study, 107 young mothers were observed at home during play with their toddlers; maternal behaviour was coded for joint attention (shared focus of mother and toddler attention) and emotional availability (e.g. sensitivity, intrusiveness, hostility). Mothers reported on aspects of their childhood history and current personal functioning and social support. A person‐centred analytic approach, using cluster analysis, revealed three distinct groups of maternal play behaviour: (1) ‘sensitive‐engaged’ (2) ‘inconsistent‐directive,’ and (3) ‘intrusive‐prohibitive’. Multivariate analyses revealed that contextual factors in mothers' lives (e.g. childhood abuse, depressive symptomatology, partner violence, social support, and parenting self‐confidence) were differentially associated with parenting clusters. Copyright © 2007 John Wiley & Sons, Ltd.
Enhanced wear resistance of orthopaedic bearing due to the cross‐linking of poly(MPC) graft chains induced by gamma‐ray irradiation
Authors: Kyomoto Masayuki , Moro Toru , Miyaji Fumiaki , Konno Tomohiro , Hashimoto Masami , Kawaguchi Hiroshi , Takatori Yoshio , Nakamura Kozo , Ishihara Kazuhiko
Published: June 2007

We assumed that the extra energy supplied by gamma‐ray irradiation produced cross‐links in 2‐methacryloyloxyethyl phosphorylcholine (MPC) polymer grafted cross‐linked polyethylene (CLPE‐g‐MPC) and investigated its effects on the tribological properties of CLPE‐g‐MPC. In this study, we found that the gamma‐ray irradiation produced cross‐links in three kinds of regions of CLPE‐g‐MPC: poly(MPC) layer, CLPE‐MPC interface, and CLPE substrate. The dynamic coefficient of friction of CLPE‐g‐MPC slightly increased with increasing irradiation doses. After the simulator test, both the nonsterilized and gamma‐ray sterilized CLPE‐g‐MPC cups exhibited lower wear than the untreated CLPE ones. In particular, the gamma‐ray sterilized CLPE‐g‐MPC cups showed extremely low and stable wear. As for the nonsterilized CLPE‐g‐MPC cups, the weight change varied with each cup. When the CLPE surface is modified by poly(MPC) grafting, the MPC graft polymer leads to a significant reduction in the sliding friction between the surfaces that are grafted because water thin films formed can behave as extremely efficient lubricants. Such a cross‐link of poly(MPC) slightly increases the friction of CLPE by gamma‐ray irradiation but provides a stable wear resistant layer on the friction surface. The cross‐links formed by gamma‐ray irradiation would give further longevity to the CLPE‐g‐MPC cups. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008