bluuebunny/crossref_metadata_2025_split huggingface dataset:
nightskylive.net: The Night Sky Live project
Authors: Pérez‐Ramírez D. , Nemiroff R. J. , Rafert J. B. 
Published: October 2004

AbstractThe Night Sky Live project's main goal is to create a useful continuous record of the night sky. In its current implementation, it is essentially a passive observatory, designed to work autonomously. It sees from horizon to horizon and does not track the sky. A continuous camera mates a Fisheye lens to a CCD camera under the control of a laptop computer. These components are housed in a case similar in size to a large briefcase. This observatory is designed to be bolted to a rooftop and connected to power and Ethernet, and is programmed remotely over the Internet. In addition to information about weather and seeing conditions, there are many scientific objectives established by the Night Sky Live project. The data is considered public domain immediately upon recording. Currently, these cameras are allocated at major professional observatories all over the World. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of the Pan‐STARRS telescopes
Authors: Hodapp K. W. , Kaiser N. , Aussel H. , Burgett W. , Chambers K. C. , Chun M. , Dombeck T. , Douglas A. , Hafner D. , Heasley J. , Hoblitt J. , Hude C. , Isani S. , Jedicke R. , Jewitt D. , Laux U. , Luppino G. A. , Lupton R. , Maberry M. , Magnier E. , Mannery E. , Monet D. , Morgan J. , Onaka P. , Price P. , Ryan A. , Siegmund W. , Szapudi I. , Tonry J. , Wainscoat R. , Waterson M. 
Published: October 2004

AbstractPan‐STARRS, the Panoramic Survey Telescope and Rapid Response System, is a project by the Institute for Astronomy, University of Hawaii, to first develop a single wide field synoptic survey telescope (Pan‐STARRS‐1) followed by a system of four such telescopes. It is designed to accomplish many of the science goals envisioned by the Decadal Review for the Large Synoptic Survey Telescope (LSST). The primary mission of Pan‐STARRS is the detection of potentially hazardous asteroids (PHA), secondary science objectives are a (nearly) all‐sky survey, a medium‐deep survey, an ultra‐deep survey, and studies of transients and variable objects. This paper presents the current status of the telescope system design, with emphasis on the optics. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic orbits of potential interferometric binaries
Authors: Fekel F. C. , Tomkin J. 
Published: October 2004

AbstractWe are obtaining high‐resolution, red‐wavelength spectra at McDonald and Kitt Peak National Observatory to improve the orbits of known spectroscopic binaries that are potential targets for ground‐based optical interferometers. The combination of such observations will produce three‐dimensional orbits from which very accurate masses and orbital parallaxes can be obtained for double‐lined systems. This spectroscopic program will be expanded and placed on the menu of the 2 meter Automatic Spectroscopic Telescope of Tennessee State University once it commences routine operation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Blazar variability studies with the 1.3 m Robotically Controlled Telescope and the automated 0.6 m Bell Observatory telescope
Authors: Carini M. T. , Barnaby D. , Mattox J. R. , Walters R. , Poteet C. , Wills W. , Gelderman R. , Davis D. , Everett M. , Guinan E. , Howell S. , McGruder C. H. 
Published: October 2004

AbstractOne of the key programs on the 1.3 m Robotically Controlled Telescope (RCT) located at Kitt Peak National Observatory and the 0.6 m telescope at the Bell Observatory operated by Western Kentucky University is a study of the variability of the class of Active Galactic Nuclei (AGN) known as Blazars. Blazars are highly variable on timescales of minutes to decades and this variability is seen across the electromagnetic spectrum. In addition, they display a featureless spectrum, thus continuum variability provides the only diagnostic of these objects. Variability provides information on the size of the emission region responsible for the observed variations and when observations are obtained at multiple wavelengths, it can be used to discriminate between emission models. However, traditional ground based observations are limited in a variety of ways. We will discuss how an automated facility, with time dedicated to this astrophysically interesting problem, can overcome many of these limitations, and we show results from the Bell Observatory as well as some of the first results of Blazar observations from the RCT. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Meteorological monitoring system of TÜBİTAK National Observatory
Authors: Koçak M. , Selam S. O. , Keskin V. 
Published: October 2004

AbstractA custom meteorological monitoring system was constructed to reliably monitor the meteorological parameters of the site of TÜBİTAK National Observatory (TÜBİTAK: The Scientific and Technical Research Council of Turkey). The site is located on a mountain top known as Bakįrlįtepe about 50 km west of the Antalya City at a height of 2547 m. The system has software (C‐based data acquisition/archiving structure and PHP based WEB monitoring support) and micro‐controller based control electronics, fiber based custom designed encoder sensors (for wind speed and direction) and transmission lines using fiberoptic to RS232 transcievers. The constructed system can be used in any robotic telescope project for data monitoring and alert system creation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A 2‐m robotic telescope project
Authors: Geyl R. , Gashut H. 
Published: October 2004

AbstractThis paper reports a recently started project for a 2‐m diameter robotic telescope dedicated to astronomy and education. After a brief recall of SAGAM‐REOSC background in this domain, the project will be presented with more details on the telescope optics, mount and control system, the dome, the coating chamber and the weather station. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐performance liquid chromatographic method for simultaneous determination of sophoridine and matrine in rat plasma
Authors: Li Yumin , Min Guangtao , Xue Qunji , Chen Liren , Liu Weimin , Chen Hao 
Published: October 2004

AbstractA high‐performance liquid chromatographic (HPLC) method is described for the simultaneous determination of sophoridine and matrine in rat plasma. Sophoridine and matrine in the resulting supernatant of the plasma deproteinized with acetonitrile containing an internal standard (acetanilide) were directly determined by reversed‐phase HPLC and ultraviolet detection. The result of limits of quantitation for matrine and sophoridine were 200 and 350 ng/mL in plasma, respectively, and recovery of both analytes was greater than 98%. The assay was linear from 250 to 4000 ng/mL for matrine and from 500 to 8000 ng/mL for sophoridine. Variation over the range of the standard curve was less than 15%. The method was used to determine the concentration–time proﬁles of matrine and sophoridine in the plasma following oral administration of Kexieling tablets, which is one of the preparations of Kudouzi at a dose equivalent to 30 and 60 mg/kg of matrine and sophoridine, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Imaging the Selective Binding of Synapsin to Anionic Membrane Domains
Authors: Murray Jill , Cuccia Louis , Ianoul Anatoli , Cheetham James J. , Johnston Linda J. 
Published: October 2004

AbstractSynapsins are membrane‐associated proteins that cover the surface of synaptic vesicles and are responsible for maintaining a pool of neurotransmitter‐loaded vesicles for use during neuronal activity. We have used atomic force microscopy (AFM) to study the interaction of synapsin I with negatively charged lipid domains in phase‐separated supported lipid bilayers prepared from mixtures of phosphatidylcholines (PCs) and phosphatidylserines (PSs). The results indicate a mixture of electrostatic binding to anionic PS‐rich domains as well as some nonspecific binding to the PC phase. Interestingly, both protein binding and scanning with synapsin‐coated AFM tips can be used to visualize charged lipid domains that cannot be detected by topography alone.
Identification and Biosynthesis of an Aggregation Pheromone of the Storage Mite Chortoglyphus arcuatus
Authors: Schulz Stefan , Fuhlendorff Jens , Steidle Johannes L. M. , Collatz Jana , Franz Jörg‐Thomas 
Published: October 2004

AbstractIn an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC‐MS by use of a closed‐loop stripping apparatus (CLSA) or solid‐phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)‐4,6,8‐trimethyldecan‐2‐one (4R,6R,8R‐8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter.
Synthesis and Degradation of Nucleobases and Nucleic Acids by Formamide in the Presence of Montmorillonites
Authors: Saladino Raffaele , Crestini Claudia , Ciambecchini Umberto , Ciciriello Fabiana , Costanzo Giovanna , Di Mauro Ernesto 
Published: October 2004

AbstractWe describe the role of formamide, a product of the hydrolysis of hydrogen cyanide, as precursor of several components of nucleic acids under prebiotic conditions. When formamide is heated in the presence of montmorillonites, the efficient one‐pot synthesis of purine, adenine, cytosine, and uracil is obtained. Along with these nucleobases, several components of the inosine pathway are obtained: 5‐aminoimidazole‐4‐carboxamide, 5‐formamidoimidazole‐4‐carboxamide and hypoxanthine. This almost complete catalogue of nucleic acid precursors is accompanied by N9‐formylpurine, which, containing a masked glycosidic bond in its formyl moiety, is a plausible precursor of purine acyclonucleosides. In addition, montmorillonites differentially affect the rate of degradation of nucleobases when embedded in 2′‐deoxyoligonucleotides; namely, montmorillonites protect adenine and guanine from the degradative action of formamide, while thymine degradation is enhanced. The oligonucleotide backbone reactivity to formamide is also affected; this shows that the interaction with montmorillonites modifies the rate of abstraction of the Hα and Hβ protons on the sugar moieties.
NMR Backbone Assignment of a Protein Kinase Catalytic Domain by a Combination of Several Approaches: Application to the Catalytic Subunit of cAMP‐Dependent Protein Kinase
Authors: Langer Thomas , Vogtherr Martin , Elshorst Bettina , Betz Marco , Schieborr Ulrich , Saxena Krishna , Schwalbe Harald 
Published: October 2004

AbstractProtein phosphorylation is one of the most important mechanisms used for intracellular regulation in eukaryotic cells. Currently, one of the best‐characterized protein kinases is the catalytic subunit of cAMP‐dependent protein kinase or protein kinase A (PKA). PKA has the typical bilobular structure of kinases, with the active site consisting of a cleft between the two structural lobes. For full kinase activity, the catalytic subunit has to be phosphorylated. The catalytic subunit of PKA has two main phosphorylation sites: Thr197 and Ser338. Binding of ATP or inhibitors to the ATP site induces large structural changes. Here we describe the partial backbone assignment of the PKA catalytic domain by NMR spectroscopy, which represents the first NMR assignment of any protein kinase catalytic domain. Backbone resonance assignment for the 42 kDa protein was accomplished by an approach employing 1) triply (2H,13C,15N) labeled protein and classical NMR assignment experiments, 2) back‐calculation of chemical shifts from known X‐ray structures, 3) use of paramagnetic adenosine derivatives as spin‐labels, and 4) selective amino acid labeling. Interpretation of chemical‐shift perturbations allowed mapping of the interaction surface with the protein kinase inhibitor H7. Furthermore, structural conformational changes were observed by comparison of backbone amide shifts obtained by 2D 1H,15N TROSY of an inactive Thr197Ala mutant with the wild‐type enzyme.
Some Novel Binuclear Group 13 Metal Tin Hydrides Formed in Ar Matrices Following the Codeposition of the Metal Vapor with SnH4
Authors: Gaertner Benjamin , Himmel Hans‐Jörg , Macrae Victoria A. , Pardoe Jennifer A. J. , Randall Paul G. , Downs Anthony J. 
Published: October 2004

AbstractIR measurements show that co‐condensation of Al or Ga atoms (M) with SnH4in a solid Ar matrix at about 12 K results mainly in the spontaneous insertion of the metal into an SnH bond to form the MIIhydride HMSnH3. Simultaneously the Ga2dimer also reacts with SnH4, possibly to form anido‐type cluster Ga2(μ‐H)4Sn, with a metal‐deficient cubane‐like structure. All of these products are photolabile. Irradiation with visible light causes HMSnH3to tautomerize to the novel dihydrido‐bridged species H2M(μ‐H)2Sn, which decomposes in turn under broad‐band UV‐visible light (λ=200–800 nm); some H2Al(μ‐H)2Sn is formed even on deposition. The data collected from experiments with SnH4and SnD4and different reagent concentrations, together with the results of quantum chemical calculations, are used to interpret the results and elucidate the structures and bonding of the new species.
Use of Different Unsaturated Dicarboxylates Toward the Design of New 3D and 2D Networks of Copper(II)
Authors: Mukherjee Partha Sarathi , Ghoshal Debajyoti , Zangrando Ennio , Mallah Talal , Chaudhuri Nirmalendu Ray 
Published: October 2004

AbstractTwo new polymeric complexes of copper(II), [Cu(L1)(μ‐fum)(μ‐H2O)]n (1) (fum = fumarate dianion; L1 = N,N′‐dimethylethane‐1,2‐diamine) and [Cu(L2)(μ‐tp)]n (2) [tp = terephthalate dianion; L2 = N‐(2‐aminoethyl)‐3‐amino‐1‐propanol], have been synthesized. The molecular structures are determined by X‐ray crystallography. Complex 1 is a fumarato‐bridged zig‐zag 1D chain of CuII−L1, which is extended to a 3D coordination polymer through bridging water molecules. Complex 2 is a chain of CuII in which the terephthalate anions bridge in alternate bis(bidentate) and bis(monodentate) fashions. The coexistence of such types of bridging modes of terephthalate ions in a single molecule is unprecedented. The chelating terephthalate ion is linked to an equatorial and an axial site of consecutive metal ions, while the other terephthalate ion is axially linked to CuII centers. Both the complexes are characterized by variable‐temperature susceptibility measurements at room temperature down to 4 K. Fitting of the magnetic data reveals the existence of weak antiferromagnetic interactions through the bridging dicarboxylate pathways. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Coordination Chemistry of Large Diphosphanes − Directional Properties of a Calix[4]arene Proximally Substituted by Two −OCH2PPh2 Podand Arms
Authors: Kuhn Pierre , Jeunesse Catherine , Sémeril David , Matt Dominique , Lutz Pierre , Welter Richard 
Published: October 2004

AbstractThe proximally‐functionalised calixarene 5,11,17,23‐tetra‐tert‐butyl‐25,26‐bis(diphenylphosphanylmethoxy)‐27,28‐dihydroxycalix[4]arene (1), a large diphosphane in which the PIII centres are separated by 10 bonds, behaves as a chelating ligand towards NiX2 moieties (X = Cl, Br). As shown by three X‐ray studies carried out on complexes of the type [NiX2·1], the diphosphane is able to accommodate either tetrahedral or strongly distorted tetrahedral coordination geometries, but not a square planar one. In all structures, the ligand positions the nickel atom away from the calixarene axis. In the presence of methylaluminoxane (MAO), [NiCl2·1] effectively catalyses the oligomerisation of ethylene, affording C4−C12 oligomers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Lipase‐catalyzed acidolysis and phospholipase D‐catalyzed transphosphatidylation of phosphocholine
Authors: Wongsakul Sirirung , Bornscheuer Uwe T. , H‐Kittikun Aran 
Published: October 2004

AbstractTwo approaches on enzymatic phospholipid modification were studied: (1) transphosphatidylation of the 1,2‐dilauroyl‐sn‐glycero‐3‐phosphocholine (DLPC) and ethanolamine in biphasic and anhydrous organic solvent systems by phospholipase D (PLD) and (2) incorporation of oleic acid into the sn1‐position of DLPC in organic solvents with different immobilized lipases at controlled water activity. First, DLPC was chemically synthesized from glycerophosphocholine and lauric acid. Next, PLD‐catalyzed head group exchange of DLPC with ethanolamine was studied using an enzyme from Streptomyces antibioticus expressed recombinantly in E. coli. A comparison of the free PLD with the biocatalyst activated by a salt‐activation technique using KCl showed that the salt‐activated enzyme (PLD‐KCl) was 10–12 folds more active based on the amount of protein used. Thus, DLPC was quantitatively converted to 1,2‐dilauroyl‐sn‐glycero‐3‐phosphoethanolamine in an anhydrous solvent system within 12 h at 60 °C. For the acidolysis of DLPC with oleic acid, among the four lipases studied (CAL‐B, Lipozyme TL IM, Lipozyme RM IM and lipase D immobilized on Accurel EP‐100), Lipozyme TL IM showed the highest activity and incorporation of oleic acid. A quantitative incorporation was achieved at 40 °C using a 8‐fold molar excess of oleic acid in n‐hexane at a water activity of 0.11.
Recent Advances inCinchonaAlkaloid Chemistry
Authors: Hoffmann H. Martin R. , Frackenpohl Jens 
Published: October 2004

AbstractQuinine has been among the best known alkaloids for over 300 years, thanks to its antimalarial activity. In the last two decades,Cinchonaalkaloids have emerged as powerful chiral auxiliaries, resulting in some well known landmark developments in asymmetric synthesis, but more recently these alkaloidsthemselveshave been shown to undergo some remarkable transformations and skeletal shifts that are rapidly widening perspectives in the chemistry ofCinchonabases, embracing both basic and applied science. The alkaloids enter into a series of fundamental transformations that have given rise to the industrial manufacture of a host of new enantiopure materials showing promise for asymmetric syntheses and combinatorial chemistry. Stereochemical diversity, well developed conformational minima not encountered in conventional organic substrates, hydrophilic pockets and stereoelectronics contribute subtle mechanistic features and structural complexity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
β‐Lactam‐Containing Cyclopeptide Analogs
Authors: Maier Thomas C. , Podlech Joachim 
Published: October 2004

AbstractCyclic peptide analogs containing a β‐lactam moiety were prepared. Reacting Fmoc‐protected amino acid‐derived diazo ketones 1, 2 with benzylidene‐protected amino esters 3, 4 in a photochemically induced Staudinger‐type reaction, trans‐substituted β‐lactams 5a/b and 6a/b were formed in 35−70% yield (dr 60:40−70:30). N‐Terminal chain elongation to the respective acyclic precursors 14, 17a/b and 19a/b was achieved using conventional peptide synthesis (i.e. the pentafluorophenyl ester protocol). After saponification, activation as pentafluorophenyl esters and subsequent cleavage of the N‐terminal Boc‐protecting group, the pre‐strained (3R,4S)‐configured isomers could be cyclized without the need for high dilution or prolonged reaction times. Contrary to this, the (3S,4R)‐configured isomers did not cyclize but gave polymeric material. The conformational stability of the cyclic peptidomimetics 16, 20, and 21 which were obtained in high yield, was elucidated by means of NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Donor‐Substituted Heptaazaphenalene as a Nonlinear Optically Active Molecule with Multiple Charge‐Transfer Transitions
Authors: Traber Boris , Oeser Thomas , Gleiter Rolf , Goebel Mark , Wortmann Rüdiger 
Published: October 2004

AbstractThe synthesis of a novel nonlinear optical (NLO) chromophore with threefold symmetry − 2,5,8‐tris(diethylamino)‐1,3,4,6,7,9,9b‐heptaazaphenalene (4) − is reported. Compound 4 was synthesized from 2,5,8‐trichloro‐1,3,4,6,7,9,9b‐heptaazaphenalene (3) through a nucleophilic aromatic substitution, its structural assignment was confirmed by X‐ray investigations, and its second‐order polarisability (β) was determined by hyper Rayleigh scattering (HRS). Compound 4 shows a very high absorbance coefficient in the UV and a remarkably large β value despite its short‐wavelength absorption. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of (ϵ‐13C‐,ϵ‐15N)‐Enriched L‐Lysine − Establishing Schemes for the Preparation of All Possible 13C and 15N Isotopomers of L‐Lysine, L‐Ornithine, and L‐Proline
Authors: Siebum Arjan H. G. , Tsang Robert K. F. , Steen Rob van der , Raap Jan , Lugtenburg Johan 
Published: October 2004

AbstractIn this paper we describe a simple synthetic strategy that, with the right rational adaptation, gives direct access to any 13C/15N isotopomer of L‐glutamate, L‐ornithine, L‐proline, L‐lysine, and L‐α amino adipic acid. This strategy also allows access to nonproteinogenic amino acids like L‐citrulline in high yields and optical purity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Rearrangement of N‐Organyloxy β‐Lactams Derived from a (4+2)/(3+2) Sequential Cycloaddition Reaction Involving Enol Ethers and Nitro Alkenes
Authors: van Berkom Leon W. A. , Kuster George J. T. , de Gelder René , Scheeren Hans W. 
Published: October 2004

AbstractThe synthesis of N‐organyloxy β‐lactams 2 by treatment of nitroso acetals 1 with a base is discussed. Based on the formation of a by‐product, a mechanism for the rearrangement to N‐organyloxy β‐lactams is proposed. This mechanism is supported by trapping of the intermediate acyl nitro compound 8 with dimethylamine. Furthermore, it was discovered that upon more forcing basic conditions these N‐organyloxy β‐lactams can rearrange further to 3‐organyloxy β‐lactams. By using a series of structurally diverse N‐organyloxy β‐lactams the generality of this novel rearrangement is demonstrated. A mechanism for the conversion of N‐organyloxy β‐lactams to 3‐organyloxy β‐lactams is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
3(5)‐(2‐Hydroxyphenyl)‐5(3)‐styrylpyrazoles: Synthesis and Diels−Alder Transformations
Authors: Silva Vera L. M. , Silva Artur M. S. , Pinto Diana C. G. A. , Cavaleiro José A. S. , Elguero José 
Published: October 2004

AbstractReactions between cinnamoyl(2‐hydroxybenzoyl)methanes and hydrazine hydrate in acetic acid gave 3‐(2‐hydroxyphenyl)‐5‐styrylpyrazoles, while the corresponding reactions with phenylhydrazine yielded 5‐(2‐hydroxyphenyl)‐1‐phenyl‐3‐styrylpyrazoles as the major products and 3‐(2‐hydroxyphenyl)‐1‐phenyl‐5‐styrylpyrazoles as by‐products. The reaction mechanism of this transformation is discussed. The first cycloaddition reactions between ortho‐benzoquinodimethane and either 3‐(2‐hydroxyphenyl)‐5‐styrylpyrazoles or 5‐(2‐hydroxyphenyl)‐1‐phenyl‐3‐styrylpyrazoles afforded 5‐[2‐(3‐aryl‐1,2,3,4‐tetrahydronaphthyl)]‐3‐(2‐hydroxyphenyl)pyrazoles or 3‐[2‐(3‐aryl‐1,2,3,4‐tetrahydronaphthyl)]‐1‐phenyl‐5‐(2‐hydroxyphenyl)pyrazoles, respectively. These cycloadducts were converted into the corresponding naphthylpyrazoles by oxidation with DDQ in dry 1,4‐dioxane. The structures of all new derivatives have been established by NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)