bluuebunny/crossref_metadata_2025_split huggingface dataset:
Learning From the Birmingham Civil Rights Institute: Documenting Teacher Development
Authors: Gregg Madeleine , Leinhardt Gaea 
Published: June 2007

This study explores the extent to which experiences designed to help preservice teachers take advantage of the Birmingham Civil Rights Institute moved them to acquire deeper knowledge of the Civil Rights Movement. The pre-service teachers came from two teacher education programs that differ with respect to situated activity, discourse communities, and authentic practice. Before and after a visiting the museum, undergraduate preservice teachers (n = 49) created concept maps, or “webs,” of the Civil Rights Movement, responded to discussion prompts in small groups, and prepared field-trip activities and follow-up lessons. Analyses of the webs, conversations, activities, and lesson plans revealed that all students gained a considerable amount of information, appreciation, and understanding. Differences in the two groups support the idea of teacher education frameworks that build from the “community of learners” model.
Education Legislation 1963–68: Various Vantage Points
Authors: COHEN WILBUR J. 
Published: June 2007

The education papers are the first category of Presidential Papers in the Lyndon B. Johnson Library to be opened to the public. Constituting some 225,000 documents, the papers provide a rich primary source for researchers in education. The new Library housing the papers is an elegant eight-story building on the campus of The University of Texas, Austin. The Library is operated by the National Archives and Records Service. Director Harry J. Middleton and a staff of seven archivists service both the collection and its users. The education papers constitute one of 62 categories used to classify the total collection. "The White House classification system is specifically designed to serve the working needs of the President's Office rather than those of researchers," commented Charles Corkran, senior archivist. However, the archivists know both the collection and the classification system well and currently are able to provide customized service on an individual basis to scholars wishing to use the papers. The stacks are closed, but page service is provided to the 28 desk-carrels in the attractive reading room. Although strict National Archives regulations ostensibly govern the use of the library, actual procedures at present appear reasonable, relaxed, and informal. Middleton recommends that researchers desiring to use the Library resources write in advance, outlining the scope of their inquiry and dates or time range. No inter-Library loan or micro-reproduction is available, but limited xerographic reproduction can be arranged by correspondence. A symposium, "Educating a Nation: The Changing American Commitment", sponsored jointly by the University and the Library, was held January 24–25 to mark the opening of the education papers. Principal speakers included John Gardner, Wilbur Cohen. Sidney Marland, William McGill and Lyndon Johnson. Dr. Cohen's address provides an overview and perspective of the new historical data now available to the educational research and development community.
Anchored Instruction and Its Relationship to Situated Cognition
Authors:   The Cognition And Technology Group At Vanderbilt
Published: June 2007

In a recent Educational Researcher article, Brown, Collins, and Duguid (January-February 1989) discussed the concept of situated cognition. We explore relationships between this concept and our Technology Center’s work on anchored instruction. In the latter, instruction is anchored (situated) in videodisc-based, problem-solving environments that teachers and students can explore. We argue that situated cognition provides a broad, useful framework that emphasizes the importance of focusing on everyday cognition, authentic tasks, and the value of in-context apprenticeship training. Anchored instruction provides a way to recreate some of the advantages of apprenticeship training in formal educational settings involving groups of students. In addition, some of the principles of anchored instruction may make it possible to create learning experiences that are more effective than many that occur in traditional apprenticeship training. Together, the situated cognition and anchored instruction perspectives suggest ways to think differently about instruction, and they suggest important issues for future research.
Risk for cancer in patients with Bardet‐Biedl syndrome and their relatives
Authors: Hjortshøj Tina Duelund , Grønskov Karen , Rosenberg Thomas , Brøndum‐Nielsen Karen , Olsen Jørgen H. 
Published: June 2007

AbstractBardet‐Biedl syndrome (BBS) is a rare, autosomal recessive disease with retinal dystrophy leading to blindness, postaxial polydactyly, truncal obesity, learning disabilities, male hypogenitalism, and renal anomalies. Heterozygous carriers of a BBS mutation are not thought to present symptoms of BBS; however, a previous study reported an increased risk of renal cancer among relatives of patients with BBS. This finding was based on the identification of three parents with renal cell carcinoma, representing a 17‐fold increased risk. We performed a population‐based study in Denmark to examine the incidence of cancer in 116 BBS patients and 428 relatives (96 families) through record linkage of information from files of the Retinitis Pigmentosa Registry, the Central Population Registry, and the Danish Cancer Registry. The clinical diagnosis of BBS was molecularly confirmed in 52% of the patients. Among the patients, two cancers were reported, with 4.3 expected. The cancers were an embryonal carcinoma of the testis in a 23‐year‐old man and an acoustic neuroma in a 51‐year‐old man. Among the relatives, 30 cancers were observed, with 45.2 expected. No renal cancers were observed in the two groups. These data do not support the suggested increased risk for renal cancer in relatives of patients with BBS. © 2007 Wiley‐Liss, Inc.
Gespannte Metallocenophane und ähnliche metallorganische Ringe mit π‐Kohlenwasserstoffliganden und Übergangsmetallzentren
Authors: Herbert David E. , Mayer Ulrich F. J. , Manners Ian 
Published: June 2007

AbstractDie Strukturen, Bindungsverhältnisse und Ringöffnungsreaktionen gespannter cyclischer Kohlenstoffverbindungen sind ein fester Bestandteil des Lehrbuchwissens. Gespannte metallorganische Verbindungen mit Übergangsmetallzentren blicken hingegen auf eine viel kürzere Geschichte zurück: Erst jüngere Arbeiten zu ihrer Synthese und ihren Eigenschaften deckten faszinierende Aspekte ihrer Struktur, Bindungsverhältnisse und Reaktivität auf. Auf der Grundlage der Untersuchungen zu gespannten Ferrocenophanen wurden vielfältige gespannte metallorganische Ringe mit unterschiedlichen Metallzentren, π‐Kohlenwasserstoffliganden und Brücken entwickelt. Solche gespannten Spezies können unter Ringöffnung an Oberflächen binden (und diese funktionalisieren) oder durch Ringöffnungspolymerisationen leicht verarbeitbare Metallopolymere bilden. Dieser Aufsatz fasst den aktuellen Stand der Synthese und Strukturbestimmung sowie die Kenntnisse über die elektronische Struktur und die Reaktivität gespannter metallorganischer Ringe mit π‐Kohlenwasserstoffliganden und d‐Block‐Metallen zusammen.
Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers
Authors: Greiner Andreas , Wendorff Joachim H. 
Published: June 2007

AbstractElectrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon‐black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.
Determination of sirolimus in rabbit arteries using liquid chromatography separation and tandem mass spectrometric detection
Authors: Zhang Jun , Rodila Ramona , Watson Pamela , Ji Qin , El‐Shourbagy Tawakol A. 
Published: June 2007

AbstractSirolimus, an effective immunosuppressive agent, is used for drug eluting stents. During stent development, an analytical method for the determination of sirolimus in tissue needs to be established. Normally, tissue samples are homogenized and then analyzed against the calibration standards prepared in a tissue homogenate. This approach provides insufficient control of the homogenization process. In this paper, tissue quality control samples were introduced for the optimization of the homogenization process during method development, but also allowance for the performance evaluation of the entire analytical process. In addition, a new approach using rabbit blood as a homogenization medium was developed to stabilize sirolimus in rabbit tissue homogenates. Calibration standards and quality controls were prepared by spiking different sirolimus working solutions into rabbit blood. Homogenization quality control samples were prepared by injecting other sirolimus working solutions into empty test tubes and pre‐cut arteries within pre‐defined masses. A high‐throughput homogenization procedure was optimized based on the specific chemical properties of sirolimus. The linear dynamic range was between 49.9 pg/mL and 31.9 ng/mL to accommodate the expected artery homogenate concentrations. Additionally, quality controls in rabbit blood were also used in the extraction to support the calibration standards. The accuracy and precision of the quality controls in rabbit blood reflect the extraction performance and the accuracy and precision of the homogenization tissue quality controls reflect the overall performance of the method. The mean bias was between −4.5 and 0.2% for all levels of quality controls in the blood and between 4.8 and 14.9% for all levels of the homogenization tissue quality controls. The CVs of all concentration levels were ≤5.3% for the quality controls in blood and ≤9.2% for the homogenization tissue quality controls. The method was successfully applied to determine the concentration of sirolimus in the rabbit arteries. Copyright © 2007 John Wiley & Sons, Ltd.
LC‐MS/MS determination of 2‐(4‐((2‐(2S,5R)‐2‐Cyano‐5‐ethynyl‐1‐pyrrolidinyl)‐2‐oxoethylamino)‐4‐methyl‐1‐piperidinyl)‐4‐pyridinecarboxylic acid (ABT‐279) in dog plasma with high‐throughput protein precipitation sample preparation
Authors: Kim Joseph , Flick Jeanette , Reimer Michael T. , Rodila Ramona , Wang Perry G. , Zhang Jun , Ji Qin C. , El‐Shourbagy Tawakol A. 
Published: June 2007

AbstractAs an effective DPP‐IV inhibitor, 2‐(4‐((2‐(2S,5R)‐2‐Cyano‐5‐ethynyl‐1‐pyrrolidinyl)‐2‐oxoethylamino)‐4‐methyl‐1‐piperidinyl)‐4‐pyridinecarboxylic acid (ABT‐279), is an investigational drug candidate under development at Abbott Laboratories for potential treatment of type 2 diabetes. In order to support the development of ABT‐279, multiple analytical methods for an accurate, precise and selective concentration determination of ABT‐279 in different matrices were developed and validated in accordance with the US Food and Drug Administration Guidance on Bioanalytical Method Validation. The analytical method for ABT‐279 in dog plasma was validated in parallel to other validations for ABT‐279 determination in different matrices. In order to shorten the sample preparation time and increase method precision, an automated multi‐channel liquid handler was used to perform high‐throughput protein precipitation and all other liquid transfers. The separation was performed through a Waters YMC ODS‐AQ column (2.0 × 150 mm, 5 µm, 120 Å) with a mobile phase of 20 mm ammonium acetate in 20% acetonitrile at a flow rate of 0.3 mL/min. Data collection started at 2.2 min and continued for 2.0 min. The validated linear dynamic range in dog plasma was between 3.05 and 2033.64 ng/mL using a 50 µL sample volume. The achieved r2 coefficient of determination from three consecutive runs was between 0.998625 and 0.999085. The mean bias was between −4.1 and 4.3% for all calibration standards including lower limit of quantitation. The mean bias was between −8.0 and 0.4% for the quality control samples. The precision, expressed as a coefficient of variation (CV), was ≤4.1% for all levels of quality control samples. The validation results demonstrated that the high‐throughput method was accurate, precise and selective for the determination of ABT‐279 in dog plasma. The validated method was also employed to support two toxicology studies. The passing rate was 100% for all 49 runs from one validation study and two toxicology studies. Copyright © 2007 John Wiley & Sons, Ltd.
Quantification of tenatoprazole in rat plasma by HPLC: validation and its application to pharmacokinetic studies
Authors: Nirogi Ramakrishna , Kandikere Vishwottam , Mudigonda Koteshwara , Bhyrapuneni Gopinadh 
Published: June 2007

AbstractA simple, reliable HPLC method with UV detection (295 nm) in rat plasma was developed and validated for quantification of tenatoprazole, a novel proton pump inhibitor, which is in clinical trials. Following a single‐step liquid–liquid extraction, the analyte and internal standard were separated using an isocratic mobile phase on a reverse phase C18 column. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 10%. A linear dynamic range of 20–6000 ng/mL was established. This HPLC method was validated with between‐batch and within‐batch precision of 2.9–6.3 and 1.4–5.8%, respectively. The between‐batch and within‐batch accuracy was 95.1–104.1 and 92.4–101.0%, respectively. This validated method is simple and repeatable enough to be used in pharmacokinetic studies. Copyright © 2007 John Wiley & Sons, Ltd.
Facts and Challenges in the Understanding of the Biosynthesis of Peptaibols by Trichoderma
Authors: Kubicek Christian P. , Komoń‐Zelazowska Monika , Sándor Erzsébet , Druzhinina Irina S. 
Published: June 2007

AbstractSpecies of the mitosporic filamentous fungal genus Trichoderma are prominent producers of both short (7–11 residues) and long (18–20 residues) peptaibols and peptaibiotics, which are thought to be involved in their interaction with other living systems. Numerous reviews are available regarding biodiversity, structure, and mode of action of these peptide derivatives, but little emphasis has been paid to the physiology and genetics of their formation. In this review article, we used the recent knowledge on biosynthesis and production of these components to speculate on some of the unknown points. We also highlight areas where further research is most urgently needed.
Total Synthesis in Solution and Conformational Analysis of the Peptaibol Cervinin and Selected Analogues
Authors: Baldini Chiara , Bellanda Massimo , Peggion Cristina , Djontu Albert Legrand , Atagua Come , Mammi Stefano , Toniolo Claudio 
Published: June 2007

AbstractThe total synthesis in solution and chemical characterization of the antibacterial undecamer peptaibol cervinin, its C‐terminal (Lol‐Ac) derivative, also naturally occurring, and three selected analogues modified at the N‐ and/or C‐terminus(i) to improve the affinity to the membrane environment, are described. A solution conformational analysis in different media, performed by the combined use of FT‐IR, CD, and 2D‐NMR techniques, clearly shows a significant 310‐like helicity for these Aib‐Pro rich peptides. The hydrophilicity/lipophilicity characteristics of the final compounds significantly influence their membrane‐modifying properties.
Synthesis, and Structural and Biological Studies of Efrapeptin C Analogues
Authors: Jost Micha , Weigelt Sven , Huber Thomas , Majer Zsuzsanna , Greie Jörg‐Christian , Altendorf Karlheinz , Sewald Norbert 
Published: June 2007

AbstractA series of analogues of efrapeptin C (1), with variations in the central tripeptide epitope (positions 6–8), were prepared by a combination of solid‐ and solution‐phase peptide syntheses. The conformations of the modified compounds 2–6 were investigated by circular‐dichroism (CD) spectroscopy to differentiate between 310‐ and α‐helical secondary structures. The inhibitory activities of the new compounds towards F1‐ATPase from E. coli were determined. The modified congeners 3–5 were less active by one order of magnitude compared to 1 (Ki 10 μM), and 6 was completely inactive. Our experiments demonstrate that the flexible, central tripeptide epitope, comprising positions 6–8 in 1, is crucial for molecular recognition, even slight sequence modifications being hardly tolerated.
Supramolecular Structure of Self‐Assembling Alamethicin Analog Studied by ESR and PELDOR
Authors: Milov Alexander D. , Samoilova Marina I. , Tsvetkov Yuri D. , Jost Micha , Peggion Cristina , Formaggio Fernando , Crisma Marco , Toniolo Claudio , Handgraaf Jan‐Willem , Raap Jan 
Published: June 2007

AbstractThree analogs of alamethicin F50/5, labelled with the TOAC (=‘2,2,6,6‐tetramethylpiperidin‐1‐oxyl‐4‐amino‐4‐carboxylic acid’) spin label at positions 1 (Alm1), 8 (Alm8), and 16 (Alm16), resp., were studied by Electron‐Spin‐Resonance (ESR) and Pulsed Electron–Electron Double‐Resonance (PELDOR) techniques in solvents of different polarity to investigate the self‐assembly of amphipathic helical peptides in membrane‐mimicking environments. In polar solvents, alamethicin forms homogeneous solutions. In the weakly polar chloroform/toluene 1 : 1 mixture, however, this peptide forms aggregates that are detectable at 293 K by ESR in liquid solution, as well as by PELDOR in frozen, glassy solution at 77 K. In liquid solution, free alamethicin molecules and their aggregates show rotational‐mobility correlation times τr of 0.87 and 5.9 ns, resp. Based on these values and analysis of dipole–dipole interactions of the TOAC labels in the aggregates, as determined by PELDOR, the average number N of alamethicin molecules in the aggregates is estimated to be less than nine. A distance‐distribution function between spin labels in the supramolecular aggregate was obtained. This function exhibits two maxima: a broad one at a distance of 3.0 nm, and a wide one at a distance of ca. 7 nm. A molecular‐dynamics (MD)‐based model of the aggregate, consisting of two parallel tetramers, each composed of four molecules arranged in a ‘head‐to‐tail’ fashion, is proposed, accounting for the observed distances and their distribution.
Ligand‐Induced Extramembrane Conformation Switch Controlling Alamethicin Assembly and the Channel Current
Authors: Futaki Shiroh , Asami Koji 
Published: June 2007

AbstractIn this review, we describe our approach to creating artificial receptor‐channel proteins or sensor systems, using an extramembrane segment conformationally switchable by external stimuli. Alamethicin is known to self‐assemble in membranes to form ion channels with various open states. Employment of an α‐helical leucine‐zipper segment resulted in the effective modulation of the association states of alamethicin to produce a single predominant channel‐open state. A decrease in the helical content of the extramembrane segments was found to induce a channel‐current increase. Therefore, conformational changes in the extramembrane segments induced by the interaction with ligands can be reflected in the current levels.
Enzymatic Reaction in a Vesicular Microreactor: Peptaibol‐Facilitated Substrate Transport
Authors: Kropacheva Tatyana N. , Raap Jan 
Published: June 2007

AbstractCatalytic reactions performed with enzymes localized in lipid vesicles or in whole cells represent a new, promising approach in biocatalysis. The delivery of different substrates into these micro‐ or nano‐‘reactors’ requires a sufficient permeability of lipid membranes. To increase the permeability of lipid bilayers, one may use different membrane‐active peptides, including peptaibols. In the present study, the trypsin‐catalyzed hydrolysis of Nα‐benzoyl‐L‐arginine‐para‐nitroanilide (BAPA; 1) was studied in a phospholipid vesicular system made of phosphatidylcholine (POC), in the presence of the peptaibols alamethicin (ALM) or zervamicin IIB (ZER). Two different manners of compartmentalization of substrate and enzyme (enzyme‐ vs. substrate‐containing vesicles) were used. The kinetics parameters of the reaction in homogeneous solution and in the vesicular systems were determined. The rate of the extra‐ or intravesicular enzymatic reaction was found to be controlled by substrate diffusion through the lipid bilayer. In comparison with untreated vesicular systems, an up to seven‐fold increase in reaction rate was observed in the presence of either ALM or ZER.
Synthetic, Biologically Active Amphiphilic Peptides
Authors: Yamnitz Carl R. , Gokel George W. 
Published: June 2007

AbstractAmphiphilic peptides typically consist of a peptide portion that may be 5–25 (or more) amino acids in length. The hydrophobic portion may be a single fatty acid residue, but can also be more elaborate. The main focus of this article lies on the family of synthetic anion binders (SATs) of the general structure (R1)2N‐COCH2OCH2CO‐(Aaa)n‐OR3. The most‐common R1 group is the octadecyl (C18H37) group. The most studied peptide sequence in this family is (Gly)3‐Pro‐(Gly)3, although different sequences (and longer and shorter peptides) have been prepared as well. The C‐terminal ester residue providing the most effective anion release from liposomes is heptyl (C7H15), although many others have been examined. The compound (C18H37)2N‐COCH2OCH2CO‐(Gly)3‐Pro‐(Gly)3‐OBn (Bn=benzyl) was found to mediate Cl− transport in mouse epithelial cells.
Spirodionic Acid, a Novel Metabolite from Streptomyces sp., Part 2: Total Synthesis through a Twofold Michael Addition as a Selective Spiroannelation Strategy
Authors: Siewert Jürgen , Textor Adriana , Grond Stephanie , von Zezschwitz Paultheo 
Published: June 2007

AbstractTo elucidate the structure of the new natural product spirodionic acid, which has three stereogenic centers of hitherto unknown configuration, two 4‐ethenylspiro[4.5]dec‐6‐en‐1,8‐diones with opposite relative configuration at C4 and C5 were prepared. The first access involved the synthesis of 3‐ethenyl‐2‐formylcyclopentanone (8) using a three‐component coupling process. A sequence of Michael addition to penten‐3‐one (7) and intramolecular aldol condensation then led to the highly selective formation of the 4S*,5S*‐configured spirocycle 5. In contrast, a selective spiroannelation of a cyclohexenone ring was accomplished by a novel type of twofold Michael addition to the dialkenyl ketone 11 with subsequent dehydrogenation to furnish the 4S*,5R*‐configured spirocycle 25. Diastereoselective methylation and oxidative degradation then completed a highly efficient synthesis of the natural product as prerequisite for the assignment of its absolute configuration.