bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR‐Nomenklatur: Kernspineigenschaften und Konventionen für die Angabe chemischer Verschiebungen
Authors: Berger Stefan , Zeller, Leipzig Uta 
Published: March 2004

AbstractHier wird eine vereinheitlichte Skala zur Angabe der NMR‐chemischen Verschiebungen aller Kerne relativ zur 1H‐Resonanzfrequenz von Tetramethylsilan (TMS) empfohlen. Diese Skala liefert ein genaues Verhältnis Ξ zwischen der Resonanzfrequenz eines gegebenen Kerns und der primären Referenz, der 1H‐Resonanzfrequenz von TMS in verdünnter Chloroformlösung (Volumenverhältnis φ<1:99). Die Referenzierungsverfahren werden gemeinsam mit Aspekten der praktischen Anwendung der vereinheitlichten Skala diskutiert. Ein Schwerpunkt sind die vorgeschlagenen Referenzverbindungen und die Ξ‐Werte für Sekundärreferenzen auf der vereinheitlichten Skala. Viele dieser Daten sind das Ergebnis neuer Messungen. Einige ältere Empfehlungen zur Wiedergabe chemischer Verschiebungen bleiben gültig. Die chemische Verschiebung δ wird neu definiert, um frühere Unklarheiten zu beseitigen, ohne jedoch die praktische Anwendung zu beeinflussen. Des Weiteren werden die Beziehungen zwischen der vereinheitlichten Skala und kürzlich veröffentlichten Empfehlungen für die Referenzierung in wässrigen Lösungen (speziell bei biochemischen Arbeiten) sowie die speziellen Effekte bei Festkörper‐MAS‐NMR‐Experimenten diskutiert. Insgesamt werden neun neue Empfehlungen zur chemischen Verschiebung gegeben. Darüber hinaus werden standardisierte Kernspindaten (Spinquantenzahl, Isotopen‐Häufigkeit, magnetisches Moment, gyromagnetisches Verhältnis, Rezeptivität sowie, wo angebracht, Quadrupolmoment und Linienbreitefaktor) für die stabilen (und einige instabile) Isotope aller Elemente mit einem Spin ungleich null in tabellarischer Form angegeben.
Task analysis, correspondence training, and general case instruction for teaching personal hygiene skills
Authors: Stokes John V. , Cameron Michael J. , Dorsey Michael F. , Fleming Elizabeth 
Published: March 2004

AbstractThe effect of a 10‐step task analysis, general case instruction, and correspondence training was evaluated for teaching appropriate personal hygiene following bowel movements. Correspondence training maintained a central role in this study. According to Israel (1978), the relationship between an individual's verbal and nonverbal behaviors is influential in self‐instruction training. Essentially, correspondence training encourages an individual to generate his or her own instructional cues; in consequence, the procedure can be instrumental in ensuring the maintenance and generalization of important verbal and nonverbal behavior. Three adults with developmental disabilities participated in this study. The dependent variables included the level of assistance required on each step of the task analysis and an end of sequence rating on a three‐point Likert‐type cleanliness scale. Results showed that all three participants learned to care for themselves appropriately following bowel movements. Moreover, the skills generalized to other settings and were maintained over a nine‐month period. The target skill was evaluated against the five criteria for a behavioral cusp and met the criteria for ‘an important behavior change’ (Bosch & Fuqua, 2001, p. 123). Copyright © 2004 John Wiley & Sons, Ltd.
Functional analysis and treatment of low‐rate problem behavior in individuals with developmental disabilities
Authors: Tarbox Jonathan , Wallace Michele D. , Tarbox Rachel S. F. , Landaburu Heidi J. , Williams W. Larry 
Published: March 2004

AbstractExtensive research has validated the standard functional analysis as a useful technology for identifying the function of problem behavior in individuals with developmental disabilities. The assessment of low‐rate problem behavior is one area that has yet to receive a significant amount of research. Some problem behaviors may occur at rates too low to be observed during a standard functional analysis, despite the fact that they may be highly destructive behaviors. The current study evaluated the effectiveness of initiating functional analysis sessions contingent on the occurrence of bursts of problem behavior for producing interpretable functional analysis results. While a standard functional analysis did not produce definitive results with respect to behavioral function, the ‘low‐rate’ functional analysis produced interpretable results for all three participants. Two of the three participants were available for the evaluation of treatments based on their functional analysis results. Function‐based treatments suppressed rates of problem behavior for both participants. Copyright © 2004 John Wiley & Sons, Ltd.
Contingent electric shock (SIBIS) and a conditioned punisher eliminate severe head banging in a preschool child
Authors: Salvy Sarah‐Jeanne , Mulick James A. , Butter Eric , Bartlett Rita Kahng , Linscheid Thomas R. 
Published: March 2004

AbstractWe report a case in which a Self‐Injurious Behavior Inhibiting System (SIBIS) device and a conditioned punisher were utilized to decrease and maintain suppression of severe head hitting/banging in a preschool child. After an experimental evaluation conducted at the hospital, SIBIS was implemented at home. The originality of this particular SIBIS case study is that programmed and systematic effort at establishing conditioned punishment was included in the intervention. Results indicate that a zero‐level response was rapidly reached, and that the conditioned punisher (i.e. verbal prompt + movement towards the place where SIBIS was kept) was sufficient to maintain treatment effects. Continuous assessment after treatment and formal observation session at 7 months follow‐up revealed that SIBIS could be removed from the natural environment of the child while maintaining a therapeutic effect. These results were interpreted as the effects of the explicit pairing between the delivery of electric stimulations and previously neutral stimuli, which were initially ineffective to elicit any response, or to suppress SIB. Close and extended monitoring during and after treatment failed to reveal the presence of negative side effects associated with SIBIS, whereas a number of positive effects were observed. Copyright © 2004 John Wiley & Sons, Ltd.
Computational Approaches to Activity in Rhodium‐Catalysed Hydroformylation
Authors: Gleich Dieter , Hutter Jürg 
Published: March 2004

AbstractIn this theoretical study on rhodium‐catalysed hydroformylation we examine an unmodified hydridorhodium(I) carbonyl system a together with three variants modified by the model phosphane ligands PF3 (system b), PH3 (system c) and PMe3 (system d), which show increasing basicity on the Tolman χ parameter scale. The olefinic substrate for all systems is ethene. Based on the dissociative hydroformylation mechanism, static and dynamic quantum‐mechanical approaches are made for preequilibria and the whole catalytic cycle. Agreement with experimental results was achieved with regard to the predominance of phosphane monocoordination in systems b–d, different sensitivity of unmodified and modified systems towards hydrogen pressure and the early location of the rate‐determining step. Neither the catalytic cycle as a whole nor olefin insertion as an important selectivity‐determining step gives a clear picture of activity differences among a–d. However, the crucial first catalytic step, association of ethene to the active species [HRhL3] (L=CO, PR3), may play the key role in the experimentally observed higher activity of a and systems with less basic phosphane ligands modelled by b.
Noncentrosymmetric Organic Solids with Very Strong Harmonic Generation Response
Authors: Zhao Hong , Li Yong‐Hua , Wang Xi‐Sen , Qu Zhi‐Rong , Wang Li‐Zhong , Xiong Ren‐Gen , Abrahams Brendan F. , Xue Ziling 
Published: March 2004

AbstractThe molten reaction of 2‐naphthol, 4‐(aminomethyl)pyridine, and 4‐pyridinecarboxaldehyde at about 180 °C yields trans‐2,3‐dihydro‐2,3‐di(4′‐pyridyl)benzo[e]indole (1) which possesses two chiral centers, rather than an expected Betti‐type reaction product with only one chiral carbon center. The same reactions, using 3‐pyridinecarboxaldehyde, 4‐cyanobenzaldehyde, or 3‐ cyanobenzaldehyde instead of 4‐pyridinecarboxaldehyde produce the related compounds trans‐2,3‐dihydro‐2‐(4′‐pyridyl)‐3‐(3′′‐pyridyl)benzo[e]indole (2), trans‐2,3‐dihydro‐2‐(4′‐pyridyl)‐3‐(4′′‐cyanophenyl)benzo[e]indole (3), and trans‐2,3‐dihydro‐2‐(4′‐pyridyl)‐3‐(3′′‐cyanophenyl)benzo[e]indole (4), respectively. This reaction proceeds with a high degree of stereoselectivity with a trans/cis ratio of about 98:2 at elevated temperature. Compounds 1, 2, and 4 crystallize in a noncentrosymmetric space group (Pca21, Pca21, and Cc), while compound 3 has a chiral space group (P21). These successfully acentric packing arrangements are probably due to the molecule bearing both two chiral centers and potential hydrogen‐bonding groups. Furthermore, the reaction of racemic 6‐hydroxy‐2′‐methyl‐2‐naphthaleneacetic acid with ethyl‐2‐cyano‐1‐(4′‐pyridyl)acrylic acetate in the presence of piperidine gives 1‐pyridyl‐2‐ethoxycarbonyl‐3‐amino‐1H‐naphtho[2,1‐b]pyran‐2′‐methylacetic acid (5), which likewise crystallizes in a chiral space group. All of compounds are second harmonic generation (SHG) active, and have a very strong SHG response approximately about 8.0, 5.0, 12.0, 6.0, and 1.4 (for 1–5 compounds) times that of urea. Ferroelectric property measurements indicate that compounds 1, 2, 4, and 5 may display ferroelectric behavior.
Kinetic Precipitation of Solution‐Phase Polyoxomolybdate Followed by Transmission Electron Microscopy: A Window to Solution‐Phase Nanostructure
Authors: Zhu Yan , Cammers‐Goodwin Arthur , Zhao Bin , Dozier Alan , Dickey Elizabeth C. 
Published: March 2004

AbstractThis study aimed to elucidate the structural nature of the polydisperse, nanoscopic components in the solution and the solid states of partially reduced polyoxomolybdate derived from the {Mo132} keplerate, {(Mo)Mo5}12‐{Mo2 acetate}30. Designer tripodal hexamine‐tris‐crown ethers and nanoscopic molybdate coprecipitated from aqueous solution. These microcrystalline solids distributed particle radii between 2–30 nm as assayed by transmission electron microscopy (TEM). The solid materials and their particle size distributions were snap shots of the solution phase. The mother liquor of the preparation of the {Mo132} keplerate after three days revealed large species (r=20–30 nm) in the coprecipitate, whereas {Mo132} keplerate redissolved in water revealed small species (3–7 nm) in the coprecipitate. Nanoparticles of coprecipitate were more stable than solids derived solely from partially reduced molybdate. The TEM features of all material analyzed lacked facets on the nanometer length scale; however, the structures diffracted electrons and appeared to be defect‐free as evidenced by Moiré patterns in the TEM images. Moiré patterns and size‐invariant optical densities of the features in the micrographs suggested that the molybdate nanoparticles were vesicular.
The Advantage of Being Virtual—Target‐Induced Adaptation and Selection in Dynamic Combinatorial Libraries
Authors: Severin Kay 
Published: March 2004

AbstractNumerical simulations are presented that describe the adaptive behavior of simple dynamic combinatorial libraries (DCLs) upon addition of a target. By studying the effect of various parameters such as the network topology, the initial concentrations, the association constants, and the binding affinities, general characteristics of such systems were derived. It is shown that the adaptation may lead to the amplification of molecules with a high affinity to the target, but only for specific boundary conditions. Furthermore, it is demonstrated that the selection process can be refined by using an evolutionary approach. These results are of importance for the design of selection experiments with DCLs.
Crystallization‐Induced Asymmetric Transformation of Chiral‐at‐metal Ruthenium(II) Complexes Bearing Achiral Ligands
Authors: Hamelin Olivier , Pécaut Jacques , Fontecave Marc 
Published: March 2004

AbstractRecently, we observed that the enantiopure Λ form of the tributylammonium salt of the chiral anion tris[tetrachlorobenzene‐1,2‐bis(olato)]phosphate, also named Trisphat, was able to induce an efficient resolution of a Δ,Λ racemic mixture of cis‐[Ru(dmp)2(NCCH3)2](PF6)2 (dmp=2,9‐dimethyl‐1,10‐phenanthroline) due to the spontaneous and selective precipitation of the heterochiral pair [Δ‐Ru(dmp)2(CH3CN)2][Λ‐Trisphat]2. We report here that the combination of such a stereoselective precipitation process and irradiation results in the quantitative conversion of the initial [Ru(dmp)2(NCCH3)2]2+ racemate into only one of the two enantiomers. This is the first example in inorganic chemistry of an asymmetric transformation that leads to a chiral complex with no chiral ligand. Finally, three new racemic ruthenium bis(diimine) complexes, namely [Ru(dmp)2(NCCH3)Py](PF6)2 (Py=pyridine), [Ru(dmp)2(1,3‐diaminopropane)](PF6)2, and [Ru(dmp)2(ethylenediamine)](PF6)2 were synthesized. For all of them, crystallization‐induced asymmetric transformation proved to be an efficient way of obtaining the corresponding optically active chiral‐at‐metal complexes in high yields and with excellent stereoselectivities.
Peripheral olfactory ensheathing cells reduce scar and cavity formation and promote regeneration after spinal cord injury
Authors: Ramer Leanne M. , Au Edmund , Richter Miranda W. , Liu Jie , Tetzlaff Wolfram , Roskams A. Jane 
Published: March 2004

AbstractBridging of a lesion site and minimizing local damage to create an environment permissive for regeneration are both primary components of a successful strategy to repair spinal cord injury (SCI). Olfactory ensheathing cells (OECs) are prime candidates for autologous transplantation to bridge this gap, but little is known currently about their mechanism of action. In addition, OECs from the accessible lamina propria (LP) of the olfactory mucosa are a more viable source in humans but have yet to be tested for their ability to promote regeneration in established SCI models. Here, mouse LP‐OECs expressing green fluorescent protein (GFP) transplanted directly into both rat and mouse dorsolateral spinal cord lesion sites demonstrate limited migration but interact with host astrocytes to develop a new transitional zone at the lesion border. LP‐OECs also promote extensive migration of host Schwann cells into the central nervous system repair zone and stimulate angiogenesis to provide a biological scaffold for repair. This novel environment created by transplanted and host glia within the spinal cord inhibits cavity and scar formation and promotes extensive sprouting of multiple sensory and motor axons into and through the lesion site. Sixty days after rat SCI, serotonin‐ and tyrosine hydroxylase‐positive axons sprouted across the lesion into the distal cord, although axotomized rubrospinal axons did not. Thus, even in a xenotransplant paradigm, LP‐OECs work collaboratively with host glial cells to create an environment to ameliorate local damage and simultaneously promote a regenerative response in multiple axonal populations. J. Comp. Neurol. 473:1–15, 2004. © 2004 Wiley‐Liss, Inc.
Androgen receptor immunoreactivity in skeletal muscle: Enrichment at the neuromuscular junction
Authors: Monks Douglas Ashley , O'Bryant Erin Louise , Jordan Cynthia Lee 
Published: March 2004

AbstractPotential cellular targets of androgen action within skeletal muscle of the rat were determined by comparing the cellular distribution of androgen receptor (AR)‐positive nuclei in the highly androgen‐responsive levator ani (LA) muscle with that of the relatively androgen‐unresponsive extensor digitorum longus (EDL) muscle. We found that androgen responsiveness correlates with AR expression in muscle fibers and not in fibroblasts. Results indicate that a much higher percentage of myonuclei in the LA are AR+ than in the EDL (74% vs. 7%), correlating with differences in androgen responsiveness. Both muscles contain an equivalent proportion of AR+ fibroblasts (∼62%). AR+ nuclei were not observed in terminal Schwann cells in either muscle. These results suggest that ARs within LA muscle fibers mediate the androgen‐dependent survival and growth of the LA muscle and its motoneurons. We also observed an unexpected enrichment of AR+ myonuclei and fibroblasts proximate to neuromuscular junctions, suggesting that ARs at muscle synapses may selectively regulate synapse‐specific genes important for the survival and growth of motoneurons. Although castration reduced the proportion of AR+ fibroblasts in both muscles, the proportion of AR+ myonuclei was reduced only in the LA. As expected, testosterone treatment prevented these effects of castration but, unexpectedly, increased the proportion of AR+ myonuclei in the EDL to above normal. These results suggest that how AR expression in skeletal muscle is influenced by androgens depends not only on the particular muscle but on the particular cell type within that muscle. J. Comp. Neurol. 473:59–72, 2004. © 2004 Wiley‐Liss, Inc.
Iminohydroxamato Early and Late Transition Metal Halide Complexes − New Precatalysts for Aluminoxane‐Cocatalyzed Olefin Insertion Polymerization
Authors: Krajete Alexander , Steiner Georg , Kopacka Holger , Ongania Karl‐Hans , Wurst Klaus , Kristen Marc O. , Preishuber‐Pflügl Peter , Bildstein Benno 
Published: March 2004

AbstractWe report on new families of non‐metallocene metal precatalysts for olefin polymerization with titanium, zirconium, vanadium and nickel as the active metal sites. The novel ligand design concept is based on iminohydroxamic acids and their derivatives as the principal chelating units. Various anionic and neutral [N,O] and [N,N] ligand systems are easily accessible by a modular synthetic sequence of imidoyl chlorides with substituted hydroxylamines or hydrazines, respectively. Steric protection of the metal coordination site, a necessary requirement for suppression of chain termination pathways of non‐metallocene catalysts, is brought about by bulky aryl substituents on the imino nitrogen atoms. Crystal structures of some of the hydroxamato ligands reveal interesting intermolecular hydrogen‐bridged structures, whereas in the solid‐state structure of one titanium precatalyst a five‐membered chelate was observed, in line with the design principle of these systems. Preliminary ethylene polymerization studies with methylaluminoxane‐activated metal complexes (M = Ti, Zr, V, Ni) show that the most active systems are [N,O]NiBr2 catalysts containing neutral O‐alkyl iminohydroxamate ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Carboxy Ester Hydrolysis Promoted by a Dicopper(II) Macrocyclic Polyamine Complex with Hydroxypropyl Pendant Groups
Authors: Huang Jin , Li Shu‐An , Li Dong‐Feng , Yang De‐Xi , Sun Wei‐Yin , Tang Wen‐Xia 
Published: March 2004

AbstractA dinuclear CuII complex containing a hexaaza macrocyclic ligand bearing two 2‐hydroxypropyl pendants, 3,6,9,16,19,22‐hexaaza‐6,19‐bis(2‐hydroxypropyl)tricyclo[22.2.2.211,14]triaconta‐1,11,13,24,27,29‐hexaene (L), was synthesized. The title complex [Cu2(H−2L)Cl2]·6.5H2O was isolated as a blue crystal, orthorhombic, space group Fddd, with a = 16.4581(12), b = 32.248(2), c = 35.830(2) Å, V = 19017(2) Å3, Z = 16, R1 = 0.0690, and wR2 = 0.1546 [I > 2σ(I)]. The protonation constants of Cu2L were determined by potentiometric titration, and it was found that the alcoholic hydroxypropyl group of the complex Cu2L exhibits low pKa values of pKa1 = 7.31, pKa2 = 7.83 at 25 °C. The hydrolysis kinetics of 4‐nitrophenyl acetate (NA) promoted by the title complex have also been studied. The pH‐rate profile for Cu2L gave a sigmoidal curve and showed a second‐order rate constant of 0.39 ± 0.02 M−1 s−1 in 10% CH3CN/H2O(v/v), which is greater than that of the dinuclear CuII complex formed by a hexaaza macrocycle without pendants. The reason for the higher catalytic activity of the title complex is discussed. We found that the volume of nucleophile RO− can effect the hydrolysis of the carboxy ester, the nucleophilicity of RO− and the Lewis acidity of the metal macrocycle also affect the carboxy ester hydrolysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Unusual Two‐Dimensional Nickel(II) Complexes Based on [Ni(dien)]2+ and [M(CN)4]2− Building Blocks (M = Ni, Pd and Pt) − Synthesis, Structural Diversity and Magnetic Properties
Authors: Muga Iñaki , Gutiérrez‐Zorrilla Juan M. , Vitoria Pablo , Román Pascual , Lezama Luis , Beitia Javier I. 
Published: March 2004

AbstractThree novel polymeric compounds [Ni(dien)Ni(CN)4]n(H2O)n (1), [Ni(dien)Pd(CN)4]n (2), and [Ni(dien)Pt(CN)4]n (3) were synthesised by reaction of [{Ni(dien)(H2O)}2(μ‐ox)](PF6)2 with [M(CN)4]2− (M = Ni, Pd, Pt) in aqueous solution. The structure of these compounds contains two [Ni(dien)]2+ cationic units bridged by two [M(CN)4]2− anions in a cis fashion, generating a square‐shaped [Ni2−M2] metal core. The different linking modes between the cores afford a 2D bilayer with encapsulated water in compound 1 and corrugated layers in compounds 2 and 3. These coordination modes are compared to the different bridging modes of tetracyanometalate‐containing compounds retrieved from the CSD database. The three compounds present a very weak antiferromagnetic coupling between the octahedrally coordinated NiII ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
One‐Pot Synthesis of 1,6‐Diiodo‐2,3,4,5‐tetracarba‐nido‐hexaboranes(6) and Mechanistic Studies on the Reaction System Alkynes/BI3/NaK2.8
Authors: Nie Yong , Schwiegk Stefan , Pritzkow Hans , Siebert Walter 
Published: March 2004

AbstractAttempts to prepare the tetracarba‐nido‐octaborane(8) derivative (EtC)4(BI)4 (4) by treatment of 3‐hexyne with BI3 (2 equiv.) and NaK2.8 led to 2,3,4,5‐tetraethyl‐1,6‐diiodo‐2,3,4,5‐tetracarba‐nido‐hexaborane(6) (2a) as the predominant product with trace quantities of 4 as well as 2,3‐diethyl‐1,4,5,6,7‐pentaiodo‐2,3‐dicarba‐closo‐heptaborane(7) (5). Starting at −78 °C, reactions of 3‐hexyne, 2‐butyne or diphenylacetylene, respectively, with BI3 (1 equiv.) and NaK2.8 afforded the corresponding 1,6‐diiodo‐2,3,4,5‐tetracarba‐nido‐hexaboranes(6) 2a−c as the single carborane products. In the cases of 3‐hexyne and diphenylacetylene, the formation of hexaorganylbenzene derivatives was also detected. To confirm the formation of 4 and 5, the independent dehalogenation of cis‐3,4‐bis(diiodoboryl)‐3‐hexene (3) with NaK2.8 has been studied, which indeed affords 4 and 5, with the former being the predominant product. A mechanism for the formation of 2a has been proposed, which involves iodoboration of the alkyne to give the borylalkene 1a. This is followed by deiodination, presumably yielding the iodoborirene derivative 7, which easily dimerizes to form the 1,4‐diboracyclo‐2,5‐hexadiene derivative 8. Subsequent rearrangement leads to the final C4B2‐nido‐carborane 2a. To determine the stereochemistry of 1a, its pyridine adduct 9 (and the isomer 9′) and catechol derivative 10 (and the isomer 10′), and the diisopropylamino derivative 11 have also been prepared. The new compounds have been characterized by MS and NMR spectroscopy, and the structures of 2a, 3, 9 and 9′ were confirmed by single‐crystal X‐ray analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)