bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization, thermal analysis, and band gap of oligo‐2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol
Authors: Kaya İsmet , Bilici Ali 
Published: March 2007

AbstractThe oxidative polycondensation reaction conditions of 2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol (2M‐4‐MPIMP) by using oxidants such as air O2, H2O2 and NaOCl were studied in an aqueous alkaline medium between 30 and 90°C. The structures of synthesized monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13CNMR, and elemental analysis. The characterization was made by TG–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo (O)‐2M‐4‐MPIMP was 68% for air O2 oxidant, 68% for H2O2 oxidant, and 82% for NaOCl oxidant. According to the SEC analysis, the number– average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index (PDI) values of O‐2M‐4‐MPIMP were found to be 695, 1000 g mol−1 and 1.439, using air O2, and 670, 795 g mol−1 and 1.187, using NaOCl, and 645, 790 g mol−1 and 1.225, using H2O2, respectively. TG–DTA analyses were shown to be stable of O‐2M‐4‐MPIMP against thermal decomposition. The weight losses of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were found to be 98.46% and 89.54% at 1000°C, respectively. Also, electrical conductivity of the O‐2M‐4‐MPIMP was measured, showing that the polymer is typical semiconductor. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of monomer and oligomer were determined from the onset potentials for n‐doping and p‐doping, respectively. Optical energy gaps (Eg) of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were calculated from UV–vis measurements. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Adsorption and desorption properties of expanded poly(tetrafluoroethylene) films grafted with DMAEMA and their regeneration
Authors: Yamada Kazunori , Takagi Chiyo , Hirata Mitsuo 
Published: March 2007

AbstractAn investigation was undertaken on the adsorption and desorption properties of the expanded poly (tetrafluoroethylene) (ePTFE) films grafted with 2‐(dimethylamino)ethyl methacrylate (DMAEMA) to anionic dye anions with one to three sulfonic groups in response to temperature changes. The amount of adsorbed metanil yellow (MY) anions increased with the grafted amount and most of the dimethylamino groups appended to the grafted PDMAEMA chains worked as an adsorption site to MY anions for the DMAEMA‐grafted ePTFE (ePTFE‐g‐PDMAEMA) films with the grafted amounts of higher than 1.1 mmol/g. When the dye‐anion‐adsorbed ePTFE‐g‐PDMAEMA films were alternately immersed in water at two different temperatures, dye anions were desorbed from the ePTFE‐g‐PDMAEMA films at higher temperatures without any chemical agents. The amount of desorbed dye anions increased with an increase in the temperature of water from 40 to 80°C. Desorption of dye anions is caused by either deprotonation of dimethylamino groups appended to the grafted PDMAEMA chains or thermosensitive contraction of the grafted PDMAEMA chains. These results indicate that the ePTFE‐g‐PDMAEMA films can be applied as a regenerative ion‐exchange membrane for adsorption and desorption processes of anionic compounds in response to the temperature change. The thermally regenerative ion‐exchange properties of the ePTFE‐g‐PDMAEMA films was superior to that of the PE‐g‐PDMAEMA films reported in our previous article in the fact that the total degree of desorption was higher for the ePTFE‐g‐PDMAEMA films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Vasculitis in the antiphospholipid syndrome. A cause of ischemia responding to corticosteroids
Authors: Goldberger Edward , Elder Rachel C. , Schwartz Robert A. , Phillips Paul E. 
Published: March 2007

AbstractA 63‐year‐old woman with atherosclerotic peripheral vascular disease and the lupus anticoagulant developed ischemia of the right lower extremity, requiring progressive amputations. Pathologic specimens revealed inflammatory vasculitis in multiple arteries. Her serum showed anticardiolipin antibodies in high titer. Treatment with high‐dose corticosteroids reversed the ischemic process. In patients with antiphospholipid antibodies, thrombosis is the most common pathologic finding associated with cutaneous lesions and/or gangrene. Vasculitis, although uncommon, is known to occur and may respond to corticosteroid therapy.
Selective deficiency of c1s associated with a systemic lupus erythematosus—like syndrome. Report of a case
Authors: Suzuki Yoshio , Ogura Yosuke , Otsubo Osamu , Akagi Kunihiko , Fujita Teizo 
Published: March 2007

AbstractWe describe a patient who developed a systemic lupus erythematosus‐like syndrome characterized by bilateral malar erythema, antinuclear antibody, and anti—double‐stranded DNA antibody. He was started on hemodialysis (3 times/week) because of renal failure. He completely lacked total hemolytic complement (CH50) activity, which was subsequently determined to be due to the absence of the first component of complement (CI). The specificity was further defined, by Ouchterlony analysis using anti‐CIs antiserum, and was found to be the C1 subcomponent C1s. There was no absence of C1r. We conclude that this is a case of selective deficiency of C1s.
Introductory bioinformatics exercises utilizing hemoglobin and chymotrypsin to reinforce the protein sequence‐structure–function relationship
Authors: Inlow Jennifer K. , Miller Paige , Pittman Bethany 
Published: March 2007

AbstractWe describe two bioinformatics exercises intended for use in a computer laboratory setting in an upper‐level undergraduate biochemistry course. To introduce students to bioinformatics, the exercises incorporate several commonly used bioinformatics tools, including BLAST, that are freely available online. The exercises build upon the students' background knowledge of hemoglobin and chymotrypsin, and foster a better understanding of how protein sequence relates to structure and function.
Utilization of integrated Michaelis‐Menten equation to determine kinetic constants
Authors: Bezerra Rui M. F. , Dias Albino A. 
Published: March 2007

AbstractStudents of biochemistry and related biosciences are urged to solve problems where kinetic parameters are calculated from initial rates obtained at different substrate concentrations. Troubles begin when they go to the laboratory to perform kinetic experiments and realize that usual laboratory instruments do not measure initial rates but only substrate or product concentrations as a function of reaction time. To overcome this problem we present a methodology which uses the integrated form of Michaelis‐Menten equation. The method presented has a theoretical and pedagogic basis which is not as arbitrary as other approaches. Here we present and describe the methodology for analyzing time course data together with some examples of the essential computer procedures to implement these analyses. To simplify the understanding of this methodology the experimental examples are confined to linear inhibitions and experimental points utilized are the same from which the initial rates are determined.
The personal response: A novel writing assignment to engage first year students in large human biology classes
Authors: Moni Roger W. , Moni Karen B. , Lluka Lesley J. , Poronnik Philip 
Published: March 2007

AbstractThe teaching of highly valued scientific writing skills in the first year of university is challenging. This report describes the design, implementation, and evaluation of a novel written assignment, The Personal Response and accompanying Peer Review, in the course, Human Biology (BIOL1015) at The University of Queensland. These assignments were the first assessment tasks of the course and were set early in the first semester of university. BIOL1015 had a diverse cohort of 319 first year students from five bachelor degree programs, primarily from Pharmacy and Human Movement Studies. Audio files in the form of interviews with eminent biomedical scientists were obtained from a leading public radio program. Students used these files as triggers to submit a short but highly structured assignment written from a personal perspective and in an expressive style. Evaluations revealed that overall, students found the task interesting and challenging. Students performed well, regardless of their background knowledge, disciplinary interest, or preference for topics within human biology. This study demonstrated that The Personal Response was an appropriate task for these first year students of human biology. It represents an alternative to traditional essay writing.
Diphenic Acid as a General Conformational Lock in the Design of Bihelical Structures
Authors: Karle Isabella L. , Venkateshwarlu Punna , Nagaraj Ramakrishnan , Sarma Akella V. S. , Vijay Dolly , Sastry Narahari G. , Ranganathan Subramania 
Published: March 2007

AbstractThe bihelical (figure of “∞”) topology was examined from vantages of design, crystal structures, chirality, circular dichroism (CD) studies and molecular‐orbital calculations. The minimalistic design envisaged the sequential linking of cystine to the anchor diphenic acid, which proved to be a general conformational lock. The bihelical compound 4 was obtained in two steps from diphenic anhydride 1 and cystine di‐OMe. The chirality of 4 arises largely from the L‐cystine. The bihelical compound 5 obtained from D‐cystine di‐OMe was found, by X‐ray crystallography, CD studies, and optical rotation, to be the perfect mirror image of 4 prepared from L‐cystine. The crystal structure of prototype 8, prepared by protocols used for 4 from the achiral cystine analogue cystamine, had a “U”‐shaped conformation held together by intramolecular hydrogen bonds. Analysis of 4 and 5 show that the pairs of nine‐membered β‐turn‐like constructs made compact through hydrogen bonding with DMSO hold the key for the bihelical conformation. Another factor is the need for the presence of a ligand at the Cα position. The absence of this, as in 8, allows major flexibility in the torsional angles around this critical region, promoting flexible alternatives. The CD analysis of 4, confirmed to be bihelical by X‐ray crystallography, showed a typical negative band at about 210 Å attributed to the β‐turn‐like motif, and in the positive‐band region a peak at about 227 Å, generally related to the twist of the biphenyl unit. The cystamine analogue 8, which showed a “U”‐type structure, presented a CD spectrum with no typical features. The total energy, derived from theoretical calculations by using the X‐ray structure data, support the bihelical structure for 4 and a “U”‐shaped one for 8. The limited utility of such calculations was tested with composite 9. Composite 9, in which the anchor diphenic acid is linked to cystamine on the one hand and to cystine on the other, showed a CD spectrum similar to that of 4, and this coupled with molecular‐orbital calculations, using data from 4 and 8, predict a bihelical structure for this compound.
Controlling Polymer Properties through Dynamic Metal–Ligand Interactions: Supramolecular Cruciforms Made Easy
Authors: Gerhardt Warren W. , Zucchero Anthony J. , South Clinton R. , Bunz Uwe H. F. , Weck Marcus 
Published: March 2007

AbstractA straightforward methodology towards the supramolecular synthesis of novel organometallic polymers with attractive optical properties is presented. By coordinating bifunctional fluorescent cruciform molecules through ditopic metalated pincer complexes (Pd or Pt), we have synthesized a new class of well‐defined coordination polymers that have controllable and tunable physical and photophysical properties. The formation of these new materials by employing metal coordination was monitored by 1H NMR spectroscopy, the association strength of the metal–ligand interaction was measured by isothermal titration calorimetry, the solution polymeric properties were evaluated by viscometry, and the optical properties were measured and observed by fluorescence spectroscopy. The fast and quantitative synthesis of a wide range of prefabricated monomeric cruciform and metalated‐pincer‐complex components will allow for the rapid generation, growth, and optimization of this new class of functional polymers, which have potential electronic and optical applications.
Eph receptor expression defines midline boundaries for ephrin‐positive migratory neurons in the enteric nervous system of Manduca sexta
Authors: Coate Thomas M. , Swanson Tracy L. , Proctor Thomas M. , Nighorn Alan J. , Copenhaver Philip F. 
Published: March 2007

AbstractEph receptor tyrosine kinases and their ephrin ligands participate in the control of neuronal growth and migration in a variety of contexts, but the mechanisms by which they guide neuronal motility are still incompletely understood. By using the enteric nervous system (ENS) of the tobacco hornworm Manduca sexta as a model system, we have explored whether Manduca ephrin (MsEphrin; a GPI‐linked ligand) and its Eph receptor (MsEph) might regulate the migration and outgrowth of enteric neurons. During formation of the Manduca ENS, an identified set of ∼300 neurons (EP cells) populates the enteric plexus of the midgut by migrating along a specific set of muscle bands forming on the gut, but the neurons strictly avoid adjacent interband regions. By determining the mRNA and protein expression patterns for MsEphrin and the MsEph receptor and by examining their endogenous binding patterns within the ENS, we have demonstrated that the ligand and its receptor are distributed in a complementary manner: MsEphrin is expressed exclusively by the migratory EP cells, whereas the MsEph receptor is expressed by midline interband cells that are normally inhibitory to migration. Notably, MsEphrin could be detected on the filopodial processes of the EP cells that extended up to but not across the midline cells expressing the MsEph receptor. These results suggest a model whereby MsEphrin‐dependent signaling regulates the response of migrating neurons to a midline inhibitory boundary, defined by the expression of MsEph receptors in the developing ENS. J. Comp. Neurol. 502:175–191, 2007. © 2007 Wiley‐Liss, Inc.
Deletion of α‐neurexins does not cause a major impairment of axonal pathfinding or synapse formation
Authors: Dudanova Irina , Tabuchi Katsuhiko , Rohlmann Astrid , Südhof Thomas C. , Missler Markus 
Published: March 2007

Abstractα‐Neurexins are synaptic cell‐surface molecules that are required for Ca2+‐triggered exocytosis. Mice lacking all three α‐neurexins show drastically reduced neurotransmitter release at excitatory and inhibitory synapses and die early postnatally. Although previous histological analysis of newborn α‐neurexin triple mutants revealed only a moderate reduction in the density of type II synapses in the brainstem, cell culture studies proposed that neurexins are prominently involved in synapse formation. To assess the contribution of α‐neurexins to the formation and structural properties of synapses in vivo, we performed a detailed morphological analysis of the brains from surviving adult double knockout mice lacking two of the three α‐neurexins. Despite their impaired neurotransmission, we did not observe any gross anatomical defects or changes in the distribution of synaptic proteins in adult mutants. Only mild structural alterations were found: a ∼20% reduction of neuropil area in many brain regions, resulting predominantly from shortened distal dendritic branches and fewer spines, as demonstrated by Golgi impregnation of pyramidal neurons. Quantitative electron microscopy revealed ultrastructurally normal type I and II terminals and a ∼30% decrease in the density of type II synapses in the neocortex. To exclude errors in pathfinding, we investigated axonal projections in the olfactory bulb of newborn knockouts and did not observe any changes. Therefore, α‐neurexins are not essential for the formation of the vast majority of synapses in vivo but rather regulate the function of these synapses. J. Comp. Neurol. 502:261–274, 2007. © 2007 Wiley‐Liss, Inc.
Cytological organization of the central gelatinosa in the turtle spinal cord
Authors: Trujillo‐Cenóz Omar , Fernández Anabel , Radmilovich Milka , Reali Cecilia , Russo Raúl E. 
Published: March 2007

AbstractThis paper deals with the cytological organization of the central gelatinosa (CG) in the spinal cord of juvenile (2–12 months) turtles. We found two main cell classes in the CG: one with characteristics of immature neurons, the other identified as radial glia (RG). The cells surrounding the central canal formed radial conglomerates in such a way that the RG lamellae covered the immature neurons. We found three major subpopulations of RG that expressed S‐100, glial fibrillary acidic protein, or both proteins. Electron microscopic images showed gap junctions interconnecting RG. As with the mammalian neuroepithelial cells, most CG cells displayed intrinsic polarity expressed by structural and molecular differences between the most apical and basal cell compartments. The apical zone was characterized by the occurrence of a single cilium associated with a conspicuous centrosomal complex. We found a prominent expression of the PCM‐1 centrosomal protein concentrated close to the central canal lumen. In the particular case of RG, the peripheral end feet contacted the subpial basement membrane. We also found “transitional cell forms” difficult to classify by the usual imaging approaches. Functional clues obtained by patch‐clamp recordings of CG cells defined some of them as already committed to follow the neuronal lineage, whereas others had properties of less mature or migrating cells. The CG appeared as a richly innervated region receiving terminal branches from nerve plexuses expressing γ‐aminobutyric acid, serotonin, and glutamate. The results presented here support our previous studies indicating that the CG is an extended neurogenic niche along the spinal cord of turtles. J. Comp. Neurol. 502:291–308, 2007. © 2007 Wiley‐Liss, Inc.
Crystal growth of mixed‐valence ammonium vanadates
Authors: Ren Tie‐Zhen , Yuan Zhong‐Yong , Zou Xiaodong 
Published: March 2007

AbstractA new method has been developed for the synthesis of mixed‐valence ammonium vanadate crystals. Single crystals of (NH4)2V3O8 were synthesized on a large scale by hydrothermal reduction of NH4VO3 in ethanol‐H2O solutions in the presence of triblock copolymer Pluronic P123. The crystals are shining thin plates with (001) cleavage planes. Calcination of the (NH4)2V3O8 crystals at 300°C or above resulted in pure phases of V2O5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of a layered chlorozincophosphate templated by protonated 4‐methylpiperidine
Authors: Kefi R. , Lefebvre F. , Ben Nasr C. 
Published: March 2007

AbstractA chlorozincophosphate with the composition Zn(HPO4)Cl·[C6H14N] has been synthesised under mild conditions in water medium in presence of 4‐methylpiperidine as organic template. The structure was determinated by single crystal X‐ray diffraction. The unit cell is orthorhombic (space group Pcab) with a = 8.743(9), b = 9.592(6), c = 26.573(6) Å, Z = 8 and V = 2228.91(12) Å3. The structure involves a network of ZnO3Cl and PO3(OH) tetrahedra forming macroanionic inorganic layers with four and eight‐membered rings. Charge balance is achieved by the protonated amine which is trapped in the interlayers space and interacts with the organic framework through hydrogen bonding. Solid state 31P and 13C MAS‐NMR spectroscopies are in full agreement with the X‐ray structure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation, single crystal growth and characterization of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper
Authors: Wang X. Q. , Xu D. , Ren Q. , Zhang G. H. , Sun X. B. , Hou X. Q. , Guo W. F. , Lü H. 
Published: March 2007

AbstractThe preparation and single crystal growth of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper, (I), are described. The energy gap Eg of (I) is about 2.38 eV. The nonlinear optical susceptibility χ(3) is about 1.3×10‐3 esu at 1064 nm. The characterization of (I) has been performed by electronic absorption, infrared and X‐ray powder diffraction spectroscopy. The thermal behavior of (I) has been investigated by means of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements in air. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal growth and magnetic properties of the copper coordination polymer [Cu(µ ‐C2O4)(4‐aminopyridine)2(H2O)]n
Authors: Prokofiev A. V. , Assmus W. , Remović‐Langer K. , Pashchenko V. , Tsui Y. , Wolf B. , Lang M. 
Published: March 2007

AbstractIn this paper, we consider various ways of crystal growth of the polymer [Cu(µ ‐C2O4)(4‐aminopyridine)2(H2O)]n. Single crystals of the size of 1.5×1.5×0.2 mm3 have been grown by a slow diffusion technique from solutions of the monoammine copper complex and of the mixture of potassium oxalate and aminopyridine with the stoichiometric ratio. Magnetic susceptibility and ESR measurements have been performed on single crystals large enough for investigating anisotropic properties. The susceptibility can be well described within the model of a Heisenberg antiferromagnetic spin chain. The magnetic measurements reveal a small concentration of paramagnetic moments reflecting the high quality of the single crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of 4‐(2‐hydroxyphenylamino)‐pent‐3‐en‐2‐one single crystals
Authors: Parekh B. B. , Purohit D. H. , Sagayaraj P. , Joshi H. S. , Joshi M. J. 
Published: March 2007

Abstract4‐(2‐hydroxyphenylamino)‐pent‐3‐en‐2‐one (HPAP) was synthesized and single crystals were grown by the solution growth technique using methanol as a solvent. The crystals having orthorhombic symmetry were characterized by single crystal XRD, FTIR spectroscopy, NMR spectroscopy, TGA, DSC and dielectric studies. Very less variation in the value of dielectric constant is found for different frequencies of applied field. The crystals were exhibiting positive photoconductivity and poor NLO responses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cell‐autonomous control of interferon type I expression by indoleamine 2,3‐dioxygenase in regulatory CD19+ dendritic cells
Authors: Manlapat Anna K. , Kahler David J. , Chandler Phillip R. , Munn David H. , Mellor Andrew L. 
Published: March 2007

AbstractFollowing CD80/86 (B7) and TLR9 ligation, small subsets of splenic dendritic cells expressing CD19 (CD19+ DC) acquire potent T cell regulatory functions due to induced expression of the intracellular enzyme indoleamine 2,3‐dioxygenase (IDO), which catabolizes tryptophan. In CD19+ DC, IFN type I (IFN‐α) is the obligate inducer of IDO. We now report that IFN‐α production needed to stimulate high‐level expression of IDO following B7 ligation is itself dependent on basal levels of IDO activity. Genetic and pharmacologic ablation of IDO completely abrogated IFN‐α production by CD19+ DC after B7 ligation. In contrast, IDO ablation did not block IFN‐α production by CD19+ DC after TLR9 ligation. IDO‐mediated control of IFN‐α production depended on tryptophan depletion as adding excess tryptophan also blocked IFN‐α expression after B7 ligation. Consistent with this, DC from mice deficient in general control of non‐derepressible‐2 (GCN2)‐kinase, a component of the cellular stress response to amino acid withdrawal, did not produce IFN‐α following B7 ligation, but produced IFN‐α after TLR9 ligation. Thus, B7 and TLR9 ligands stimulate IFN‐α expression in CD19+ DC via distinct signaling pathways. In the case of B7 ligation, IDO activates cell‐autonomous signals essential for IFN‐α production, most likely by activating the GCN2‐kinase‐dependent stress response.See accompanying commentary: http://dx.doi.org/10.1002/eji.20073737184