bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and photophysical properties of some 5(2)‐aryl‐2(5)‐(4‐pyridyl)oxazoles and related oxadiazoles and furans
Authors: Herbert Hall J. , Chien Joseph Yuming , Kauffman Joel M. , Litak Peter T. , Adams Jeffrey K. , Henry Ronald A. , Hollins Richard A. 
Published: March 2009

AbstractA number of 5‐aryl‐2‐(4‐pyridyl)oxazoles, a 2‐aryl‐5‐(4‐pyridyl)oxazole, the related oxadiazole and furan, several 2‐(4‐pyridyl)cycloalkano[d]oxazoles, and many of their quaternary salts were prepared. No single standard synthesis was effective for preparation of more than a few of the 25 free bases described; methods often unique to a base were employed. Minor variations in structure sometimes produced large differences in absorption and emission wavelengths, as well as in the magnitude of the extinction coefficient. The salts are of interest as laser dyes, scintillation fluors, biological stains, and shifters for luminescent solar concentrators.
Assignment of the NMR spectra of a potent ribonucleotide reductase inactivator ‐ utilization of HMQC‐TOCSY to establish connectivities in exchange broadened spectra
Authors: Blumenkopf Todd A. , Crouch Ronald C. , Martin Gary E. 
Published: March 2009

AbstractInverted and Suppressed Direct Response (IDR and SDR, respectively) HMQC‐TOCSY experiments are evaluated relative to the conventional HMQC‐TOCSY experiment in the assignment of the congested proton and carbon spectra of a 2‐acetylpyridine thiocarbonohydrazone used to potentiate the antiviral drug acyclovir. Spectra with moderate overlap can be most expeditiously interpreted using the inverted direct response HMQC‐TOCSY variant; spectra with severe overlap can be more readily interpreted if direct responses are suppressed.
Polycondensed nitrogen heterocycles. Part24. Pyrrolo[3,4‐c]isoquinolinone by thermal rearrangement of a pyrrolylbenzotriazinone
Authors: Cirrincione Girolamo , Almerico Anna Maria , Dattolo Gaetano , Aiello Enrico , Diana Patrizia , Mingoia Francesco 
Published: March 2009

AbstractRearrangement under acidic conditions of the pyrrolylbenzotriazinone7afforded the pyrrolylbenzamides10and11. By thermal rearrangement instead, the first fully aromatic derivative of the pyrrolo[3,4‐c]isoquinoline ring system9was obtained.
1,2,4‐Triazolo[4,3‐c]pyrimidines from 4‐acylhydrazinopyrimidines
Authors: Cocco Maria Teresa , Congiu Cenzo , Maccioni Antonio , Onnis Valentina 
Published: March 2009

AbstractThe reaction of N1‐acetylacetamidrazones 1 with N‐[bis(methylthio)methylene]cyanamide (2) at room temperature in the presence of potassium carbonate in dimethyl sulfoxide affords good yields of ethyl 4‐acylhydrazino‐2‐amino‐6‐methylthio‐5‐pyrimidine carboxylate 3. By briefly refluxing compounds 3 in dimethyl sulfoxide, 1,2,4‐triazolo[4,3‐c]pyrimidine derivatives 4 were obtained. When equimolecular amounts of N1‐acylacetamidrazones and compounds 2 were refluxed in dimethyl sulfoxide/toluene, compounds 4 were obtained directly.
Tautomerism in quinaldyl ketones
Authors: Douglass James E. , Michelena Elba , Ataei Ali , Dotson Darin L. , Lo Herng‐Hsiang 
Published: March 2009

AbstractThe quinaldyl ketone, 4‐phenyl‐3‐(quinolin‐2‐yl)‐butan‐2‐one was prepared by two methods: (a) benzylation of 1‐(1H‐quinolin‐2‐ylidene)propan‐2‐one in the presence of sodium hydride in dimethylformamide and (b) by the benzylative demethoxycarbonylation of methyl 2‐(1H‐quinolin‐2‐ylidene)‐3‐oxobutanoate in the presence of lithium bromide in hexamethylphosphoramide at 135°. In the absence of acid, the compound exists exclusively in the tautomeric form, 4‐phenyl‐3‐(1H‐quinolin‐2‐ylidene)butan‐2‐one.
Large scale synthesis of 4‐ethylpyrimidine
Authors: Butters M. 
Published: March 2009

AbstractThe reaction of methyl propionyl acetate with formamidine acetate in the presence of sodium methoxide produces 6‐ethyl‐4(3H)‐pyrimidinone (1) in 67% isolated yield. Reaction with phosphorus oxychloride and subsequent catalytic hydrogenolysis affords 4‐ethylpyrimidine (3) in 41% overall yield.
Self‐determination group or extra‐legal governance agency? The multifaceted nature of the Oodua people's congress in Nigeria
Authors: Guichaoua Yvan 
Published: March 2009

AbstractThe paper contributes to the understanding of the origins of violent non‐legal organisations in West Africa by focusing on the emergence and the evolution of the Oodua People's Congress (OPC), a movement aiming at defending the interests of the Yoruba people in Nigeria. It discusses the causes of its gradual transformation from a self‐determination group ready to use political violence into an agency of local extra‐legal governance tolerated by official federal authorities. This evolution may reflect the normalisation of the OPC in Nigeria's weak democracy. Copyright © 2009 John Wiley & Sons, Ltd.
The female gonad in two species of Microplana (Platyhelminthes, Tricladida, Rhynchodemidae): Ultrastructural and cytochemical investigations
Authors: Falleni Alessandra , Lucchesi Paolo , Ghezzani Claudio , McDonald Jillian C. , Jones Hugh D. 
Published: March 2009

AbstractThe female gonad of the land planarians Microplana scharffi and Microplana terrestris consists of two small germaria located ventrally in the anterior third of the body and of two ventro‐lateral rows of oblong vitelline follicles distributed between the intestinal pouches. Both these structures are enveloped by a tunica composed of an outer extracellular lamina and an inner sheath of accessory cells. Oocyte maturation is characterized by the appearance of chromatoid bodies and the development of endoplasmic reticulum and Golgi complexes. These organelles appear to be correlated with the production of egg granules with a fenestrated/granular content of medium electron density, about 4–5 μm in diameter, which remain dispersed in the ooplasm of mature oocytes. On the basis of cytochemical tests showing their glycoprotein composition, and their localization in mature oocytes, these egg granules have been interpreted as yolk. In the vitelline follicles, vitellocytes show the typical features of secretory cells with well‐developed rough endoplasmic reticulum and Golgi complexes involved in the production of eggshell globules and yolk. The eggshell globules, which appear to arise from repeated coalescences of two types of Golgi‐derived vesicles, contain polyphenols and, when completely mature, they measure about 1–1,2 μm in diameter and show a meandering/concentric content pattern as is typical of the situation observed in most Proseriata and Tricladida. Mature vitellocytes also contain a large amount of glycogen and lipids as further reserve material. On the basis of the ultrastructural features of the female gonad and in relation to the current literature the two species of rhynchodemids investigated appear to be closely related to the freshwater planarians belonging to the family Dugesiidae. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.
Nanocarbon materials: probing the curvature and topology effects using phonon spectra
Authors: Gupta Sanju , Saxena Avadh 
Published: March 2009

AbstractMuch has been learned from the use of resonance Raman spectroscopy and high‐resolution transmission electron microscopy techniques about the micro‐/nanoscopic structure of various nanostructured carbons. However, they still possess some features that are not entirely understood particularly in terms of topological characteristics, which go beyond making a distinction with just the geometrical structure at nanoscale. To effectively utilize the potential of these materials for technological needs, understanding both the geometrical and topological structure and perhaps relating these attributes to physical (optical/electronic, lattice vibrational) properties become indispensable. Here, we make an attempt to describe the differences between various nanostructures and provide geometrical and topological property assessment semiquantitatively by monitoring the phonon spectra using resonance Raman spectroscopy thereby also capturing the electronic spectra. We elucidate the notion of global topology and curvature for a range of technologically important nanoscale carbons including tubular (single‐, double‐ and multiwalled nanotubes, peapod), spherical (hypo‐ and hyperfullerenes, onion‐like carbon) and complex (nanocones, nanohorns, nanodisks and nanorings) geometries. To demonstrate the proof‐of‐concept, we determined the variation in the prominent Raman bands of the respective materials, represented as D, G and D* (the overtone of D) bands, as a possible topological or curvature trend due to their sensitivity toward structural modification. The latter arises from local topological defects such as pentagons giving rise to curved nanocarbons. In this study, we provide systematics of their variation with respect to their geometric forms and compare with highly oriented pyrolytic graphite and monolayer graphene since the nanocarbons discussed are their derivatives. Once established, this knowledge will provide a powerful machinery to understand newer nanocarbons and indeed point to an unprecedented emergent paradigm of global topology/curvature → property → functionality relationship. We emphasize that these concepts are applicable to other topologically distinct nanomaterials, which include boron‐nitride (BN) nanotubes and nanotori, helical gold nanotubes and Möbius conjugated organics. Copyright © 2009 John Wiley & Sons, Ltd.
Multitoxin extraction and detection of trichothecenes in cereals: an improved LC‐MS/MS approach
Authors: Santini Antonello , Ferracane Rosalia , Somma Maria Carmela , Aragón Alejandro , Ritieni Alberto 
Published: March 2009

AbstractBACKGROUND: Many multiresidual methods to evaluate natural occurrence of Fusarium toxins are already reported in the scientific literature but a new rapid, reliable, cost‐efficient and high‐sensitivity method for the simultaneous determination of several fusariotoxins is always welcome. Nivalenol (NIV), deoxynivalenol, fusarenon‐X (FUS‐X), 3‐acetyldeoxynivalenol, diacetoxyscirpenol (DAS), HT‐2 toxin, T‐2 toxin, neosolaniol (NEO), zearalanone and zearalenone (ZON) belong to the most common mycotoxins in food matrix grains, e.g., wheat and maize. The proposed method is a multitoxin analytical method that combines high‐performance liquid chromatography (HPLC), atmospheric pressure chemical ionization (APCI), triple‐quadrupole tandem mass spectrometry (LC‐MS/MS) under the selected reaction monitoring (SRM) mode, and it is focused on the optimization of the sample preparation without the need for any cleanup.RESULTS: Three different methods for sample preparation and for the simultaneous extractions of the above‐mentioned fusariotoxins were tested: two of these were followed by a different cleanup step for comparison, while the extraction method proposed in this work, which uses an 84% (v/v) acetonitrile aqueous solution, sample homogenization and subsequent filtration, was validated without any further cleanup step.CONCLUSION: Calibration curves for all analytes are linear, except DAS, HT‐2 and ZON, over the working range of 10–1000 µg kg−1. The calibration curve of DAS was linear between 10 and 500 µg kg−1, although the curves of HT‐2 and ZON were linear in the range 10–250 µg kg−1. Squared correlation coefficients (R2) were in the range 0.995–0.998 for the all point calibration curves. The lowest limits of detection (LOD) were found for DON and ZAN with 0.5 and 0.2 µg kg−1, respectively, while the highest LODs were obtained for NIV, FUS‐X and NEO, with 3.3 µg kg−1 for each toxin. Copyright © 2009 Society of Chemical Industry
Towards more relaxed conditions for a gamma‐ray laser: Methods to realize induced transparency for nuclear resonant gamma radiation
Authors: Odeurs J. , Hoy G.R. , Rostovtsev Y. , Shakhmuratov R.N. 
Published: March 2009

AbstractNuclear quantum optics deals with the resonant interaction of gamma‐radiation and nuclei, generally incorporated in a solid‐state material. Single gamma‐rays interact with an ensemble of nuclei. The properties of the resonantly forward‐scattered gamma‐radiation depend on the details of the interaction. An external modification of the nuclear energies will influence the interactions, and hence the properties of the radiation. Several techniques are proposed to reduce the resonant absorption of the gamma‐rays, creating a nuclear medium that is partially transparent: nuclear‐level‐mixing induced transparency, modification of nuclear levels by means of an optical laser, phase‐shift‐induced transparency. Interference is crucial in all this. The partial transparency could be exploited to study special effects such as slow gamma‐radiation and gain without population inversion. It could also be of importance for the realization of a gamma‐ray laser.
Antibiotics: Natural products essential to human health
Authors: Demain Arnold L. 
Published: March 2009

AbstractFor more than 50 years, natural products have served us well in combating infectious bacteria and fungi. Microbial and plant secondary metabolites helped to double our life span during the 20th century, reduced pain and suffering, and revolutionized medicine. Most antibiotics are either (i) natural products of microorganisms, (ii) semi‐synthetically produced from natural products, or (iii) chemically synthesized based on the structure of the natural products. Production of antibiotics began with penicillin in the late 1940s and proceeded with great success until the 1970–1980s when it became harder and harder to discover new and useful products. Furthermore, resistance development in pathogens became a major problem, which is still with us today. In addition, new pathogens are continually emerging and there are still bacteria that are not eliminated by any antibiotic, e.g., Pseudomonas aeruginosa. In addition to these problems, many of the major pharmaceutical companies have abandoned the antibiotic field, leaving much of the discovery efforts to small companies, new companies, and the biotechnology industries. Despite these problems, development of new antibiotics has continued, albeit at a much lower pace than in the last century. We have seen the (i) appearance of newly discovered antibiotics (e.g., candins), (ii) development of old but unutilized antibiotics (e.g., daptomycin), (iii) production of new semi‐synthetic versions of old antibiotics (e.g., glycylcyclines, streptogrammins), as well as the (iv) very useful application of old but underutilized antibiotics (e.g., teicoplanin). © 2009 Wiley Periodicals, Inc. Med Res Rev, 29, No. 6, 821–842, 2009
Anatomical information is needed in ultrasound imaging of muscle to avoid potentially substantial errors in measurement of muscle geometry
Authors: Bénard Menno R. , Becher Jules G. , Harlaar Jaap , Huijing Peter A. , Jaspers Richard T. 
Published: March 2009

AbstractThis study validates two‐dimensional (2D) ultrasound measurements of muscle geometry of the human medial gastrocnemius (GM) and investigates effects of probe orientation on errors in these measurements. Ultrasound scans of GM muscle belly were made both on human cadavers (n = 4) and on subjects in vivo (n = 5). For half of the cadavers, ultrasound scans obtained according to commonly applied criteria of probe orientation deviated 15° from the true fascicle plane. This resulted in errors of fascicle length and fascicle angle up to 14% and 23%, respectively. Fascicle‐like structures were detectable over a wide range of probe tilt and rotation angles, but they did not always represent true fascicles. Errors of measurement were either linear or quadratic functions of tilt angle. Similar results were found in vivo. Therefore, we conclude that similar errors are likely to occur for in vivo measurements. For all cadavers, at the distal end of GM, the true fascicle plane was shown to be perpendicular to the distal aponeurosis. Using transverse images of GM to detect the curvature of the deep aponeurosis at the distal end of the muscle belly is a simple strategy to help identify the fascicle plane. For subsequent longitudinal imaging, probe alignment within this plane will help minimize measurement errors of fascicle length, fascicle angle, and muscle thickness. Muscle Nerve, 2009
Characterisation of tannin‐containing herbal drugs by HPLC
Authors: Møller Charlotte , Hansen Steen Honoré , Cornett Claus 
Published: March 2009

AbstractIntroductionHerbal drugs containing tannins are characterised in the European Pharmacopoeia by their tannin content analysed by the old, nonspecific, colorimetric Folin–Ciocalteu method. The result of the analysis is a single figure relating to the content of tannins, but this does not provide much information on the identity or status of the herbal drug.ObjectiveIn the present paper methods for obtaining more detailed information of the constituents in these herbal drugs are described.MethodologyThe methods developed are based on a reversed‐phase gradient HPLC system coupled to DAD, fluorescence, electrochemical and MS detectors.ResultsThe HPLC system developed provides characteristic fingerprints of the herbal drugs when using UV detection at 250 nm. The fingerprints may be used for identification of tannin‐containing herbal drugs. Methanolysis of the herbal drug generated methyl gallate and ellagic acid, which were analysed in the HPLC system. The molar ratio between methyl gallate and ellagic acid may also be used for the identification of herbal drugs.ConclusionsAn HPLC system equipped with selective detectors was shown to be valuable in the identification of herbal tannin. Most promising was fingerprinting using UV detection, but methanolysis followed by HPLC also proved useful. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of injection molding conditions on the morphology of polymer structural foams
Authors: Barzegari M. Reza , Rodrigue Denis 
Published: March 2009

AbstractThis study investigates the relations between processing conditions and morphology of injection molded structural foams. The samples were produced by adjusting five process parameters (blowing agent concentration, mold temperature, melt temperature, injection pressure, and back pressure) at four different levels. The experiments were based on the design of experiments (DOE) analysis with a Taguchi method, and the results were used to determine the optimum conditions to produce high quality foams in terms of low skin thickness, small cell sizes, and narrow cell size distribution combined with low foam density and high cell density. The conclusions revealed that blowing agent concentration and injection pressure were the most influential factors. Using the optimum conditions predicted from the DOE, a validation test was performed and confirmed the results. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
The influence of the stress relaxation and creep recovery times on the viscoelastic properties of open cell foams
Authors: Greco Antonio , Lionetto Francesca 
Published: March 2009

AbstractThe aim of this work is to study the mechanical behavior of flexible polyurethane foams used in cushioning applications. In particular, the differences between slow recovery (SR) and fast recovery (FR) foams are highlighted. To characterize the flexible polyurethane foams, creep and hysteresis tests were performed at different strain rate, stress levels, and temperatures. Significant differences were observed between the SR and FR foams, particularly in terms of residual deformation after unloading, hysteresis area, and creep behavior at different stress levels. Creep compliance at different stress levels was compared with a Voigt‐Kelvin model. Stress–strain loading curves were compared with a phenomenological model originally modified to account for the strain rate dependence. In both cases, it is possible to show that the main differences observed in the behavior of the foams are due to the different relaxation and recovery times of the foams. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Improving homework accuracy: Interdependent group contingencies and randomized components
Authors: Reinhardt Danielle , Theodore Lea A. , Bray Melissa A. , Kehle Thomas J. 
Published: March 2009

AbstractHomework is an often employed teaching strategy that has strong positive effects on academic achievement across grade levels, content areas, and student ability levels. To maximize academic learning, accuracy of homework should be addressed. The present investigation employed a multiple‐baseline design across academic behaviors to examine the efficacy of randomization of the interdependent group contingency on the homework accuracy of six fourth‐grade students enrolled in a general education class. Results demonstrated that the interdependent group contingency coupled with randomly selected components improved accuracy of homework performance. Specifically, participants demonstrated gains in all three subject areas. Limitations and future research are also addressed. © 2009 Wiley Periodicals, Inc.
Building a foundation for structure‐based cellulosome design for cellulosic ethanol: Insight into cohesin‐dockerin complexation from computer simulation
Authors: Xu Jiancong , Crowley Michael F. , Smith Jeremy C. 
Published: March 2009

AbstractThe organization and assembly of the cellulosome, an extracellular multienzyme complex produced by anaerobic bacteria, is mediated by the high‐affinity interaction of cohesin domains from scaffolding proteins with dockerins of cellulosomal enzymes. We have performed molecular dynamics simulations and free energy calculations on both the wild type (WT) and D39N mutant of the C. thermocellum Type I cohesin‐dockerin complex in aqueous solution. The D39N mutation has been experimentally demonstrated to disrupt cohesin‐dockerin binding. The present MD simulations indicate that the substitution triggers significant protein flexibility and causes a major change of the hydrogen‐bonding network in the recognition strips—the conserved loop regions previously proposed to be involved in binding—through electrostatic and salt‐bridge interactions between β‐strands 3 and 5 of the cohesin and α‐helix 3 of the dockerin. The mutation‐induced subtle disturbance in the local hydrogen‐bond network is accompanied by conformational rearrangements of the protein side chains and bound water molecules. Additional free energy perturbation calculations of the D39N mutation provide differences in the cohesin‐dockerin binding energy, thus offering a direct, quantitative comparison with experiments. The underlying molecular mechanism of cohesin‐dockerin complexation is further investigated through the free energy profile, that is, potential of mean force (PMF) calculations of WT cohesin‐dockerin complex. The PMF shows a high‐free energy barrier against the dissociation and reveals a stepwise pattern involving both the central β‐sheet interface and its adjacent solvent‐exposed loop/turn regions clustered at both ends of the β‐barrel structure.