bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Experiences and Clinical Implications of Restenosis and Drug-Eluting Stents: Part 2
Authors: Chong Pang H , Cheng Judy WM
Published: March 2004

OBJECTIVE

To review early clinical experience and future implications of drug-eluting stents (DES) in percutaneous coronary interventions.

DATA SOURCES

Using the search terms sirolimus, paclitaxel, and drug-eluting stents, a literature review was conducted to identify peer-reviewed articles and abstracts in MEDLINE (1966—June 2003). Recent meeting abstracts were also accessed through the American Heart Association and the American College of Cardiology Web sites. Citations from available articles were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

Published reviews and studies showing the effects of in-stent restenosis and drug-coated and -eluting stents were evaluated and reviewed.

DATA SYNTHESIS

Current antiplatelet and antithrombotic therapy have proven successful in preventing acute in-stent thrombosis, but not in-stent restenosis. Recently, stents eluted with certain antimitotic agents have demonstrated positive findings in reducing restenosis (eg, sirolimus, paclitaxel-eluting stents) compared with bare-metal stents. However, data regarding long-term benefits and adverse effects are only beginning to accumulate.

CONCLUSIONS

While the current clinical efficacy and safety of DES appear promising, further investigations are required to examine long-term efficacy, safety, and cost-effectiveness. Subanalysis of the current data may help to determine the specific patient population that may benefit maximally from DES.
Transitory Ataxia Related to Topically Administered Lidocaine
Authors: Perney Pascal , Blanc François , Mourad Georges , Blayac Jean-Pierre , Hillaire-Buys Dominique
Published: March 2004

OBJECTIVE

To report 2 cases of transitory cerebellar ataxia related to lidocaine administered topically for endoscopy.

CASE SUMMARIES

Two patients developed transitory cerebellar ataxia a few minutes after local anesthesia using lidocaine 10% spray and lidocaine 2% orally for a bronchoscopy and transesophageal echocardiography. This effect completely disappeared in 3–5 hours. In neither case was an alternate etiology of cerebellar ataxia identified. The second patient had previously experienced a similar reaction to lidocaine.

DISCUSSION

Several central neurologic effects of lidocaine have been reported, but until now, only few cases of cerebellar ataxia. In these 2 cases, the Naranjo probability scale indicated that a probable and a highly probable relationship existed between lidocaine administration and the transitory cerebellar ataxia.

CONCLUSIONS

Cerebellar ataxia may occur after local anesthesia with lidocaine; therefore, care must be taken to avoid overdose, even when administered topically.
Recycling rice hull ash: A filler material for polymeric composites?
Authors: Chaudhary Deeptangshu S. , Jollands Margaret C. , Cser Ferenc
Published: March 2004

Born more out of necessity, the “awareness‐attitude” of our society has caused the channeling of technological developments toward immediate economic and ecological benefits. The polymer industry has a newfound interest in fillers from industrial by‐products and other waste materials having potential “recyclability.” This new class of fillers includes fillers from natural sources (e.g., natural fibers), industrial by‐products (e.g., saw dust, rice husks), and a recent entry in the form of rice husk ash—an industrial waste material–‐obtained by burning rice husks. Their recyclability and utilization has become a major driving factor in their acceptance and employability, as well as low cost and abundant availability. However, their performance in composites and processing requirements has hindered their applicability within the current economic framework. The present article reviews the performance of rice husk ash, or silica ash, in polymeric composites. Silica ash, composed mainly of silica, is obtained after burning rice husks and is a major industrial waste material in rice growing countries. Optimism surrounds the application of silica ash as a potential filler in a variety of polymeric composites, however, its performance has been limited by its inherent characteristics. This paper emphasizes the need for better characterization of silica ash to obtain an in‐depth understanding of its behaviour with the view to identifying suitable modifications to improve its performance as a filler. It is emphasized that poor understanding of silica ash as a filler is linked to the lack of surface characterization, since its behaviour is significantly linked with its surface properties. Based on this analysis, a new approach to silica ash modification is proposed. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 147–155, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20000
A comprehensive 3‐D analysis of polymer melt flow in slit extrusion dies
Authors: Huang Yihan , Gentle C. Richard , Hull J. Barry
Published: March 2004

An understanding of flow behaviour of polymer melts through a slit die is extremely important for optimizing die design and, consequently, for die performance in processing polymer sheets and films. In view of the complex nature and the physical properties of polymer melts as well as of die geometries, such as coat‐hanger dies, no simple mathematical formulae can be used to compute the flow regimes within dies. This paper illustrates the development of a three‐dimensional (3‐D) computer model of an example of a coat‐hanger die design using the computational fluid dynamics package, FIDAP, based on the finite element method. A difference of only 3.7% was found when comparing the velocity distribution at the die exit obtained from the 3‐D simulation with that calculated using a two‐dimensional analytical design procedure, indicating that full 3‐D analysis seems to be unnecessary. However it has been shown that unwanted flow phenomena and production problems can be ameliorated by means of visualization and the detailed information obtained from computer simulations. Comparative simulation results with polymers of different rheological properties in the same die are also described. The comprehensive analyses provide a means of interpretation for flow behavior, which allows modification of the die geometry for optimal design. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 111–124, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20002
Origin of Dissolved Organic Carbon Studied by UV‐vis Spectroscopy
Authors: Giancoli Barreto Sônia Regina , Nozaki Jorge , Barreto Wagner J.
Published: March 2004

Dissolved organic carbon (DOC) distributions in water from Lake Ipê, MS, Brazil, were investigated. The samplings were performed monthly (surface, 1 m depth, and bottom) from June 1999 to June 2000. Absorbance at 285 nm and DOC concentrations in mg dm—3, p(DOC), were highly correlated for the three depths. 77% of the surface, 85% for 1 m and bottom samples presented a variation between 20 dm3 g—1 cm—1 and 50 dm3 g—1 cm—1 of A(285 nm)/p(DOC), that characterizes the dissolved organic matter in lake water as essentially fulvic. The ratio A(254 nm)/p(DOC) was also sensitive for fulvic matter, and an A(250 nm)/A(365 nm) = 4 ratio was characteristic of strongly colored waters. The ratios A(436 nm)/p(DOC) for the three depths also showed a significant correlation. The predominance of fulvic acid is explained by environmental characteristics such as the tropical climate, temperatures above 18 °C, and the lake environment. It was demonstrated that the variation in the water carbon content due to different compartments in the lake can be monitored by UV‐vis spectroscopy ratios.
Thermodynamics of fluid‐phase equilibria for standard chemical engineering operations
Authors: Prausnitz John M. , Tavares Frederico W.
Published: March 2004

Thermodynamics provides one of the scientific cornerstones of chemical engineering. This review considers how thermodynamics is and has been used to provide phase equilibria as required for design of standard chemical engineering processes with emphasis on distillation and other conventional separation operations. While this review does not consider “modern” thermodynamics for high‐tech applications, attention is given to 50 years of progress in developing excess‐Gibbs‐energy models and engineering‐oriented equations of state; these developments indicate rising use of molecular physics and statistical mechanics whose application for chemical process design is made possible by increasingly powerful computers. As yet, results from molecular simulations have not had a major influence on thermodynamics for conventional chemical engineering; however, it is likely that molecular simulation methods will become increasingly useful, especially when supported by quantum‐mechanical calculations for describing intermolecular forces in complex systems. © 2004 American Institute of Chemical Engineers AIChE J, 50: 739–761, 2004
Decreasing self‐injurious behavior associated with awakening in a child with autism and developmental delays
Authors: DeLeon Iser G. , Fisher Wayne W. , Marhefka Jean‐Marie
Published: March 2004

Direct observation data revealed that self‐injurious behavior (SIB) emitted by a young boy with autism occurred primarily within one hour after waking versus all other times of the day. Experimentally manipulated scheduled awakenings supported the hypothesized relation between waking and SIB. A faded‐bedtime procedure was then implemented to stabilize his sleep patterns, which reduced awakenings by 81% and post‐waking SIB by 82%. Copyright © 2004 John Wiley & Sons, Ltd.
Tris(oxalato)phosphorus Acid and Its Lithium Salt
Authors: Wietelmann Ulrich , Bonrath Werner , Netscher Thomas , Nöth Heinrich , Panitz Jan‐Christoph , Wohlfahrt‐Mehrens Margret
Published: March 2004

The conversion of three equivalents of anhydrous oxalic acid with phosphorus pentachloride yields tris(oxalato)phosphorus acid 1, which crystallizes from diethyl ether solutions as protonated diethyl ether complex [(Et2O)2H]+[P(C2O4)3]−. The superacidic compound can be used as catalyst for Friedel–Crafts‐type reactions. Upon neutralization with lithium hydride, the lithium salt Li[P(C2O4)3] 2 is obtained, which is highly soluble in aprotic solvents and which exhibits a wide voltage window. Thus, the lithium compound is a promising candidate as electrolyte for high performance non‐aqueous batteries.
Synthesis of (E)‐α‐Hydroxy‐β,γ‐Unsaturated Amides with High Selectivity from α,β‐Epoxyamides by Using Catalytic Samarium Diiodide or Triiodide
Authors: Concellón José M. , Bernad Pablo L. , Bardales Eva
Published: March 2004

The highly stereoselective synthesis of (E)‐α‐hydroxy‐β,γ‐unsaturated amides starting from α,β‐epoxyamides, by using catalytic SmI2 or SmI3, was achieved. This transformation can also be carried out by using SmI2 generated in situ from samarium powder and diiodomethane. The starting compounds 1 are easily prepared by the reaction of enolates derived from α‐chloroamides with ketones at −78 °C. A mechanism to explain this transformation has been proposed. Cyclopropanation of (E)‐α‐hydroxy‐β,γ‐unsaturated amides has been performed to demonstrate their synthetic applications.
Hydrogenation Studies Involving Halobis(phosphine)–Rhodium(i) Dimers: Use of Parahydrogen Induced Polarisation To Detect Species Present at Low Concentration
Authors: Colebrooke Simon A. , Duckett Simon B. , Lohman Joost A. B. , Eisenberg Richard
Published: March 2004

Reaction of [RhCl(PPh3)2]2 with parahydrogen revealed that the binuclear dihydride [Rh(H)2(PPh3)2(μ‐Cl)2Rh(PPh3)2] and the tetrahydride complex [Rh(H)2(PPh3)2(μ‐Cl)]2 are readily formed. While magnetisation transfer from free H2 into both the hydride resonances of the tetrahydride and [Rh(H)2Cl(PPh3)3] is observable, neither transfer into [Rh(H)2(PPh3)2(μ‐Cl)2Rh(PPh3)2] nor transfer between the two binuclear complexes is seen. Consequently [Rh(H)2(PPh3)2(μ‐Cl)]2 and [Rh(H)2(PPh3)2(μ‐Cl)2Rh(PPh3)2] are not connected on the NMR timescale by simple elimination or addition of H2. The rapid exchange of free H2 into the tetrahydride proceeds via reversible halide bridge rupture and the formation of [Rh(H)2(PPh3)2(μ‐Cl)RhCl(H)2(PPh3)2]. When these reactions are examined in CD2Cl2, the formation of the solvent complex [Rh(H)2(PPh3)2(μ‐Cl)2Rh(CD2Cl2)(PPh3)] and the deactivation products [Rh(Cl)(H)(PPh3)2(μ‐Cl)(μ‐H)Rh(Cl)(H)(PPh3)2] and [Rh(Cl)(H)(CD2Cl2)(PPh3)(μ‐Cl)(μ‐H)Rh(Cl)(H)(PPh3)2] is indicated. In the presence of an alkene and parahydrogen, signals corresponding to binuclear complexes of the type [Rh(H)2(PPh3)2(μ‐Cl)2(Rh)(PPh3)(alkene)] are detected. These complexes undergo intramolecular hydride interchange in a process that is independent of the concentration of styrene and catalyst and involves halide bridge rupture, followed by rotation about the remaining Rh–Cl bridge, and bridge re‐establishment. This process is facilitated by electron rich alkenes. Magnetisation transfer from the hydride ligands of these complexes into the alkyl group of the hydrogenation product is also observed. Hydrogenation is proposed to proceed via binuclear complex fragmentation and trapping of the resultant intermediate [RhCl(H)2(PPh3)2] by the alkene. Studies on a number of other binuclear dihydride complexes including [(H)(Cl)Rh(PMe3)2(μ‐H)(μ‐Cl)Rh(CO)(PMe3)], [(H)2Rh(PMe3)2(μ‐Cl)2Rh(CO)(PMe3)] and [HRh(PMe3)2(μ‐H)(μ‐Cl)2Rh(CO)(PMe3)] reveal that such species are able to play a similar role in hydrogenation catalysis. When the analogous iodide complexes [RhI(PPh3)2]2 and [RhI(PPh3)3] are examined, [Rh(H)2(PPh3)2(μ‐I)2Rh(PPh3)2], [Rh(H)2(PPh3)2(μ‐I)]2 and [Rh(H)2I(PPh3)3] are observed in addition to the corresponding binuclear alkene–dihydride products. The higher initial activity of these precursors is offset by the formation of the trirhodium phosphide bridged deactivation product, [{(H)(PPh3)Rh(μ‐H)(μ‐I)(μ‐PPh2)Rh(H)(PPh3)}(μ‐I)2Rh(H)2(PPh3)2]
Solvent Effects on 195Pt and 205Tl NMR Chemical Shifts of the Complexes [(NC)5PtTl(CN)n]n− (n=0–3), and [(NC)5PtTlPt(CN)5]3− Studied by Relativistic Density Functional Theory
Authors: Autschbach Jochen , Le Guennic Boris
Published: March 2004

The 295Pt and 205Tl NMR chemical shifts of the complexes [(NC)5PtTl(CN)n]n− n=0–3, and of the related system [(NC)5PtTlPt(CN)5]3− have been computationally investigated. It is demonstrated that based on relativistically optimized geometries, by applying an explicit first solvation shell, an additional implicit solvation model to represent the bulk solvent effects (COSMO model), and a DFT exchange‐correlation potential that was specifically designed for the treatment of response properties, that the experimentally observed metal chemical shifts can be calculated with satisfactory accuracy. The metal chemical shifts have been computed by means of a two‐component relativistic density functional approach. The effects of electronic spin–orbit coupling were included in all NMR computations. The impact of the choice of the reference, which ideally should not affect the accuracy of the computed chemical shifts, is also demonstrated. Together with recent calculations by us of the Pt and Tl spin–spin coupling constants, all measured metal NMR parameters of these complexes are now computationally determined with sufficient accuracy in order to allow a detailed analysis of the experimental results. In particular, we show that interaction of the complexes with the solvent (water) must be an integral part of such an analysis.
Indium‐Mediated Regio‐ and Diastereoselective Reduction of Norbornyl α‐Diketones
Authors: Khan Faiz Ahmed , Dash Jyotirmayee , Sudheer Ch.
Published: March 2004

A novel, efficient, and regio‐ as well as diastereoselective conversion of non‐enolizable bicyclic α‐diketones into synthetically useful acyloins mediated by indium metal is described. The reduction is highly diastereoselective, leading exclusively to endo‐acyloins (endo‐hydroxyl groups) in excellent yields, and tolerates a variety of sensitive substituents, such as acetate, ester, and bridgehead halogens. The regioselectivity in the reductions of monosubstituted α‐diketones varied from 70:30 to 100:0 for the two possible isomeric alcohols. The methodology is extended to the synthesis of highly functionalized cyclopentane carboxaldehydes, potential building blocks in organic syntheses, by cleavage of the acyloins by treating them with Pb(OAc)4 in MeOH/PhH. Allylindium additions to carboxaldehydes 22 have been found to be highly diastereoselective.
Electronic and Vibrational Properties of Fluorenone in the Channels of Zeolite L
Authors: Devaux André , Minkowski Claudia , Calzaferri Gion
Published: March 2004

Fluorenone (C13H8O) was inserted into the channels of zeolite L by using gas‐phase adsorption. The size, structure, and stability of fluorenone are well suited for studying host–guest interactions. The Fourier transform IR, Raman, luminescence, and excitation spectra, in addition to thermal analysis data, of fluorenone in solution and fluorenone/zeolite L are reported. Normal coordinate analysis of fluorenone was performed, based on which IR and Raman bands were assigned, and an experimental force field was determined. The vibrational spectra can be used for nondestructive quantitative analysis by comparing a characteristic dye band with a zeolite band that has been chosen as the internal standard. Molecular orbital calculations were performed to gain a better understanding of the electronic structure of the system and to support the interpretation of the electronic absorption and luminescence spectra. Fluorenone shows unusual luminescence behavior in that it emits from two states. The relative intensity of these two bands depends strongly on the environment and changes unexpectedly in response to temperature. In fluorenone/zeolite L, the intensity of the 300 nm band (lifetime 9 μs) increases with decreasing temperature, while the opposite is true for the 400 nm band (lifetime 115 μs). A model of the host–guest interaction is derived from the experimental results and calculations: the dye molecule sits close to the channel walls with the carbonyl group pointing to an Al3+ site of the zeolite framework. A secondary interaction was observed between the fluorenone's aromatic ring and the zeolite's charge‐compensating cations.
Molecular Reactors and Machines: Applications, Potential, and Limitations
Authors: Easton Christopher J. , Lincoln Stephen F. , Barr Lorna , Onagi Hideki
Published: March 2004

Molecular reactors are miniature vessels for the assembly of reactants at the molecular level, in order to change the nature of chemical transformations. It seems probable that those that will find most immediate applications are those that change product ratios or give products which would not readily form in the absence of the reactors, and thereby afford easy access to materials that are otherwise difficult to obtain. Molecular machines consist of interrelated parts with separate functions and perform some kind of work, at the molecular level. Practical examples are likely to be relatively uncomplicated and not based on individual functions of single‐molecule devices. Instead they will probably rely on extensive redundancy of the molecular components and their interactions and reactions, as well as of the machines themselves.
Biotin is endogenously expressed in select regions of the rat central nervous system
Authors: McKay Bruce E. , Molineux Michael L. , Turner Ray W.
Published: March 2004

The vitamin biotin is an endogenous molecule that acts as an important cofactor for several carboxylases in the citric acid cycle. Disorders of biotin metabolism produce neurological symptoms that range from ataxia to sensory loss, suggesting the presence of biotin in specific functional systems of the CNS. Although biotin has been described in some cells of nonmammalian nervous systems, the distribution of biotin in mammalian CNS is virtually unknown. We report the presence of biotin in select regions of rat CNS, as revealed with a monoclonal antibody directed against biotin and with avidin‐ and streptavidin‐conjugated labels. Detectable levels of biotin were primarily found caudal to the diencephalon, with greatest expression in the cerebellar motor system and several brainstem auditory nuclei. Biotin was found as a somatic label in cerebellar Purkinje cells, in cell bodies and proximal dendrites of cerebellar deep nuclear neurons, and in red nuclear neurons. Biotin was detected in cells of the spiral ganglion, somata and proximal dendrites of cells in the cochlear nuclei, superior olivary nuclei, medial nucleus of the trapezoid body, and nucleus of the lateral lemniscus. Biotin was further found in pontine nuclei and fiber tracts, the substantia nigra pars reticulata, lateral mammillary nucleus, and a small number of hippocampal interneurons. Biotin was detected in glial cells of major tract systems throughout the brain but was most prominent in tracts of the hindbrain. Biotin is thus expressed in select regions of rat CNS with a distribution that correlates to the known clinical sequelae associated with biotin deficiencies. J. Comp. Neurol. 473:86–96, 2004. © 2004 Wiley‐Liss, Inc.
A Novel Pentacoordinated Dioxovanadium(V) Salicylaldiminate: Solvent Specific Crystallization of Dimorphs with Contrasting Coordination Geometries, Ligand Conformations and Supramolecular Architectures
Authors: Baruah Bharat , Rath Sankar Prasad , Chakravorty Animesh
Published: March 2004

The reaction of the tridentate salicylaldimine of 2‐picolylamine, C6H4(OH)CHNCH2C5H4N (HL), with bis(acetylacetonato)oxovanadium(IV) at room temperature under oxygen (or with VOSO4·5H2O plus H2O2) furnished crystalline greenish‐yellow α‐VO2(L) and green β‐VO2(L) from methanol (or ethanol) and acetonitrile (or dichloromethane), respectively. The dimorphs give rise to the same solution species as revealed by spectroscopic data (UV/Vis, 1H and 51V NMR). Both forms react with 3,5‐bis(tert‐butyl)catechol (H2dbcat) furnishing the known pseudooctahedral complex VO(L)(dbcat). In the α form the V(L) fragment is planar and the VO3N2 coordination sphere is distorted trigonal bipyramidal (τ = 0.55) with the two oxo oxygen atoms and the azomethine nitrogen atom defining the trigonal plane. In β‐VO2(L) the V(L) moiety, like that in VO(L)(dbcat), is not planar but consists of two planar parts rotated away from each other along the C−N single bond. In this case the coordination sphere is distorted square pyramidal (τ = 0.20) with the three donor sites of the L ligand and an oxo oxygen atom defining the tetragonal plane. Both the α and β crystal lattices consist of dimers which associate further to form supramolecules. The noncovalent intradimer and interdimer bonding interactions are predominantly of aromatic π‐π stacking (aryl···pyridyl and pyridyl···pyridyl) and C−H···O hydrogen bonding (azomethine···oxo and aryl···phenolato) types in the α and β dimorphs, respectively. It is proposed that the low polarizability of methanol promotes π‐π stacking of planar V(L) fragments, resulting in crystallization of the α form. When the polarizability is relatively high, as in acetonitrile, the β form crystallizes. The geometrically isomeric coordination spheres of the α and β forms are sustained by the respective supramolecular architectures. The Schiff base HL′ of 2‐hydroxynapthaldehyde and 2‐picolylamine has also afforded two forms of VO2(L′) in the same manner as for VO2(L). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Ruthenium Tetraammines as a Model of Nitric Oxide Donor Compounds
Authors: Toledo José Carlos , Silva Hildo A. S. , Scarpellini Marciela , Mori Vânia , Camargo Ademir J. , Bertotti Mauro , Franco Douglas W.
Published: March 2004

The nitric oxide liberation fromtrans‐[Ru(NH3)4(L)(NO)]3+(where L = py, 4‐pic, isn, nic,L‐His, 4‐Clpy, imN) after one‐electron‐chemical or electrochemical reduction was investigated through spectroscopic and electrochemical techniques, reaction‐product analysis and quantum‐mechanic calculations. These complexes can be formally viewed as a RuII(NO+) species and the reduction site is located on the NO ligand. TheE° for thetrans‐[RuII(NH3)4(L)(NO+)]3+/trans‐[RuII(NH3)4(L)(NO)]2+redox process ranges from 0.072 V vs. NHE (nic) to −0.118 V vs. NHE (imN). The specific rate constants for NO dissociation fromtrans‐[RuII(NH3)4(L)(NO)]2+, evaluated through double‐step chronoamperometry, range from 0.025 s−1(nic) to 0.160 s−1(ImN) at 25 °C. The [RuIINO+/RuIINO0] redox potential and the specific rate constant (k‐NO),key steps for designing nitrosyl complexes as NO‐donor drug prototypes, proved to be controlled by a judicious choice of the ligand (L) trans to NO. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Methacrylate‐Substituted Titanium‐Yttrium Mixed‐Metal Oxo Clusters
Authors: Jupa Myhedin , Kickelbick Guido , Schubert Ulrich
Published: March 2004

Upon reaction of titanium propoxide and yttrium 2‐methoxyethoxide with a sevenfold excess of methacrylic acid, three different mixed‐metal clusters were obtained, depending on the titanium to yttrium alkoxide ratio. Clusters of the type Ti4Y2(μ3‐O)4(μ2‐methacrylate)12(μ1‐methacrylate)2L2 (L = MeOCH2CH2OH or methacrylic acid), with two [TiO6] octahedra condensed to a zigzag chain of two [YO8] dodecahedra and two [TiO6] octahedra, were formed when the Ti/Y ratio in the precursor mixture was ⩾ 3.5. The structure of Ti4Y2O4(OMc)12(OCH2CH2OMe)2(McOH)2 obtained with a Ti/Y ratio of 2 in the precursor mixture, consists of a ring of four corner‐sharing [TiO6] octahedra to which two [YO8] dodecahedra are condensed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Strongly Nucleophilic RhI Centre in Square‐Planar Complexes with Terdentate (κ3) 2,2′:6′,2′′‐Terpyridine Ligands: Crystallographic, Electrochemical and Density Functional Theoretical Studies
Authors: de Pater Boke C. , Frühauf Hans‐Werner , Vrieze Kees , de Gelder René , Baerends Evert J. , McCormack Drew , Lutz Martin , Spek Anthony L. , Hartl František
Published: March 2004

RhI‐terpyridine complexes have been unambiguously formed for the first time. The 2,2′:6′,2′′‐terpyridine (tpy), 4′‐chloro‐2,2′:6′,2′′‐terpyridine (4′‐Cl‐tpy) and 4′‐(tert‐butyldimethylsilyl‐ortho‐carboranyl)‐2,2′:6′,2′′‐terpyridine (carboranyl‐tpy) ligands were used for successful syntheses and characterisation of the corresponding RhI complexes with halide co‐ligands, [Rh(X)(4′‐Y‐terpyridine)] (X = Cl, Y = H, Cl, carboranyl; X = Br, Y = H). All four neutral Rh‐tpy complexes are square planar, with Rh−X bonds in the plane of the 4′‐Y‐terpyridine ligands. Full characterisation of these dark blue, highly air‐sensitive compounds was hampered by their poor solubility in various organic solvents. This is mainly due to the formation of π‐stacked aggregates, as evidenced by the crystal structure of [Rh(Cl)(tpy)]; in addition, [Rh(Cl)(carboranyl‐tpy)] merely forms discrete dimers. The (bonding) properties of the novel RhI‐terpyridine complexes have been studied with single‐crystal X‐ray diffraction, (time‐dependent) density functional theoretical (DFT) calculations, far‐infrared spectroscopy, electronic absorption spectroscopy and cyclic voltammetry. From DFT calculations, the HOMO of the studied RhI‐terpyridine complexes involves predominantly the metal centre, while the LUMO resides on the terpyridine ligand. Absorption bands of the studied complexes in the visible region (400−900 nm) can be assigned to MLCT and MLCT/XLCT transitions. The relatively low oxidation potentials of [Rh(X)(tpy)] (X = Cl, Br) point to a high electron density on the metal centre. This makes the RhI‐terpyridine complexes strongly nucleophilic and (potentially) highly reactive towards various (small) substrate molecules containing carbon−halide bonds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Series of Molybdenum(V) Complexes with the Oxalato Ligand Engaged in Different Binding Roles − An Unusual Staggered Conformation of the μ4‐Oxalate in [{Mo2O4(η2‐C2O4)2}2(μ4‐C2O4)]6−
Authors: Modec Barbara , Brenčič Jurij V. , Koller Jože
Published: March 2004

Solvothermal reactions between mononuclear halooxomolybdates(V) and oxalic acid afforded smaller oligonuclear complexes with the oxalate ion engaged in different binding modes. The oxalate ion coordinates as a bidentate terminal ligand to each metal centre of the {Mo2O4}2+ unit to form the anion of (MeNC5H5)2[Mo2O4(η2‐C2O4)2py2] (1; py = pyridine; MeNC5H5+ = N‐methylpyridinium cation). (MeNC5H5)6[{Mo2O4(η2‐C2O4)2}2(μ4‐C2O4)] (2) with a tetradentate oxalate ion connecting two dinuclear subunits is a very rare example of a coordination compound with the oxalato ligand in a completely staggered conformation: the two CO2 entities of the μ4‐oxalate ion are rotated by 90° with respect to each other. Ab initio MO calculations on [{Mo2O4(η2‐C2O4)2}2(μ4‐C2O4)]6− revealed the isomer with the staggered conformation of the μ4‐oxalate ion to be of the lowest energy. The cyclic octanuclear anion of (MeNC5H5)2[Mo8O16(OMe)8(μ8‐C2O4)] (3) consists of four dinuclear subunits arranged around the central oxalate ion and additionally linked by pairs of methoxide bridges. Each oxygen atom of the oxalate ion bridges a pair of metal centres not connected by a metal−metal bond. The anionic part of [MeNC5H2(Me)3]2[HNC5H2(Me)3]2[Mo2O3(η2‐C2O4)4] (4) [MeNC5H2(Me)3+ = N‐methylcollidinium cation; HNC5H2(Me)3+ = protonated 2,4,6‐collidine] possesses an anti‐{Mo2O3}4+ structural fragment with a pair of bidentate oxalate ions coordinated to each molybdenum atom. The compounds were fully characterized by X‐ray structural analysis and infrared spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization
Authors: Janas Zofia , Jerzykiewicz Lucjan B. , Przybylak Katarzyna , Sobota Piotr , Szczegot Krzysztof
Published: March 2004

The mixed‐ligand complexes [Ti2(μ‐OR)2(OR)2(κ3‐tbop)2] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR)4 and H2tbop {H2tbop = 2,2′‐thiobis[4‐(1,1,3,3‐tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti2(μ‐OR)2(κ3‐tbop)2(Me)2] (2a) for R = Me and (2b) for R = Et. Controlled hydrolysis of 2b causes the evolution of methane and the formation of the titanoxane compounds [{Ti2(μ‐OEt)2(κ3‐tbop)2}2(μ‐O)2]·2CH2Cl2 (3). Structures of 1a, 1b, 2a, 2b, and 3 were confirmed by NMR spectroscopy; 1b and 3 were further investigated with X‐ray crystallography. Compounds 1a, 1b, 2a, and 2b were supported on MgCl2 and when activated with aluminum alkyls, found to effectively polymerize ethylene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Absorption, Magnetic Circular Dichroism, IR Spectra, Electrochemistry, and Molecular Orbital Calculations of Monoaza‐ and Opposite Diazaporphyrins
Authors: Ogata Hiroshi , Fukuda Takamitsu , Nakai Katsunori , Fujimura Yuichi , Neya Saburo , Stuzhin Pavel A. , Kobayashi Nagao
Published: March 2004

Electronic absorption, magnetic circular dichroism (MCD), IR spectra, and cyclic and differential pulse voltammograms of metal‐free and copper monoaza‐ and opposite diazaporphyrins are reported, together with molecular orbital (MO) calculations using the density functional theory (DFT) method. Introduction of nitrogen atoms at the meso position of porphyrins caused a blue‐shift of the B band and a red‐shift of the Q band, with a concomitant decrease and increase of the apparent absorption coefficient, respectively. On going from monoaza to diaza species, the apparent bandwidth at half‐height of the B band and the splitting of the Q band do not change significantly for metal‐free species, but increase for the copper species. The MCD peaks and troughs correspond closely to the peaks of the absorption spectra, so that these are interpreted as the superimposition of Faraday B terms. The MCD sign pattern (minus‐to‐plus on going from longer to shorter wavelengths) substantiates experimentally that the splitting between the HOMO and HOMO−1 orbital is larger than that between the LUMO and LUMO+1. Of the copper complexes of octaethylporphyrin (OEP), monoaza‐ (MAP), diaza‐ (DAP) and tetraazaporphyrins (TAP), CuTAP is the easiest to reduce and hardest to oxidize. The potential differences between the first oxidation and reduction couples were about 2.1−2.4 V. MO calculations using DFT succeeded in reproducing some of the above spectroscopic and electrochemical characteristics. In addition, some of the IR bands were assigned on the basis of the DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Assessment of the sensitivity of the computational programs DEREK, TOPKAT, and MCASE in the prediction of the genotoxicity of pharmaceutical molecules
Authors: Snyder Ronald D. , Pearl Greg S. , Mandakas George , Choy Wai Nang , Goodsaid Federico , Rosenblum I.Y.
Published: March 2004

Computational models are currently being used by regulatory agencies and within the pharmaceutical industry to predict the mutagenic potential of new chemical entities. These models rely heavily, although not exclusively, on bacterial mutagenicity data of nonpharmaceutical‐type molecules as the primary knowledge base. To what extent, if any, this has limited the ability of these programs to predict genotoxicity of pharmaceuticals is not clear. In order to address this question, a panel of 394 marketed pharmaceuticals with Ames Salmonella reversion assay and other genetic toxicology findings was extracted from the 2000–2002 Physicians' Desk Reference and evaluated using MCASE, TOPKAT, and DEREK, the three most commonly used computational databases. These evaluations indicate a generally poor sensitivity of all systems for predicting Ames positivity (43.4–51.9% sensitivity) and even poorer sensitivity in prediction of other genotoxicities (e.g., in vitro cytogenetics positive; 21.3–31.9%). As might be expected, all three programs were more highly predictive for molecules containing carcinogenicity structural alerts (i.e., the so‐called Ashby alerts; 61% ± 14% sensitivity) than for those without such alerts (12% ± 6% sensitivity). Taking all genotoxicity assay findings into consideration, there were 84 instances in which positive genotoxicity results could not be explained in terms of structural alerts, suggesting the possibility of alternative mechanisms of genotoxicity not relating to covalent drug‐DNA interaction. These observations suggest that the current computational systems when applied in a traditional global sense do not provide sufficient predictivity of bacterial mutagenicity (and are even less accurate at predicting genotoxicity in tests other than the Salmonella reversion assay) to be of significant value in routine drug safety applications. This relative inability of all three programs to predict the genotoxicity of drugs not carrying obvious DNA‐reactive moieties is discussed with respect to the nature of the drugs whose positive responses were not predicted and to expectations of improving the predictivity of these programs. Limitations are primarily a consequence of incomplete understanding of the fundamental genotoxic mechanisms of nonstructurally alerting drugs rather than inherent deficiencies in the computational programs. Irrespective of their predictive power, however, these programs are valuable repositories of structure‐activity relationship mutagenicity data that can be useful in directing chemical synthesis in early drug discovery. Environ. Mol. Mutagen. 43:143–158, 2004. © 2004 Wiley‐Liss, Inc.
Biomagnetic fluid flow in a 3D rectangular duct
Authors: Tzirtzilakis1 E. E. , Sakalis V. D. , Kafoussias N. G. , Hatzikonstantinou P. M.
Published: March 2004

The laminar, incompressible, three‐dimensional, fully developed viscous flow of a non‐conducting biomagnetic fluid in a impermeable rectangular duct is numerically studied in the presence of an applied magnetic field. It is assumed that the magnetic field strength is sufficiently strong to saturate the biofluid and the magnetization is given as a function of the magnetic field intensity. The system of the partial differential equations, resulting after the introduction of appropriate non‐dimensional variables, is solved applying an efficient numerical technique based on a pressure‐linked pseudotransient method on a common grid. Results concerning the existence and the uniqueness of the solution, are also given. The obtained results, for different values for the parameters entering into the problem under consideration, show that the flow is appreciably influenced by the presence of the magnetic field. Copyright © 2004 John Wiley & Sons, Ltd.
Analysis of hypersonic flows using finite elements with Taylor–Galerkin scheme
Authors: Kessler Martin P. , Awruch Armando M.
Published: March 2004

The aim of the present work is to introduce a formulation for the numerical analysis of three‐dimensional thermochemical non‐equilibrium hypersonic flows, using the finite element method and the Taylor–Galerkin scheme and adopting Park's 2‐temperature, 5‐species (N2, O2, NO, N and O) and 17‐reaction model. Examples using Euler and Navier–Stokes equations are included and compared with experimental and numerical works presented by other authors. The results are close to those analysed by other researches and a good computational performance was obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Dominant negative Ras enhances lactogenic hormone‐induced differentiation by blocking activation of the Raf–Mek–Erk signal transduction pathway
Authors: Cerrito Maria Grazia , Galbaugh Traci , Wang Weihan , Chopp Treasa , Salomon David , Cutler Mary Lou
Published: March 2004

Epidermal growth factor (EGF) and Ras mitogenic signal transduction pathways are frequently activated in breast carcinoma and inhibit mammary differentiation and apoptosis. HC11 mouse mammary epithelial cells, which differentiate and synthesize β‐casein following growth to confluency and stimulation with lactogenic hormones, were used to study EGF‐dependent signaling during differentiation. Blocking Mek–Erk or phosphotidylinositol‐3‐kinase (PI‐3 kinase) signaling with specific chemical inhibitors enhanced β‐casein promotor‐driven luciferase activity. Because EGF stimulation of HC11 cells resulted in the activation of Ras, the effect of activated Ras (RasV12) or dominant negative (DNRasN17) on lactogen induced differentiation was examined. HC11 cell lines expressing RasV12 or DNRasN17 under the control of a tetracycline (tet)‐responsive promotor were constructed. Activated RasV12 expression resulted in reduced tyrosine phosphorylation of Stat5 and a delay in β‐casein expression in response to prolactin. However, the expression of tet‐regulated DNRasN17 and adenovirus‐encoded DNRasN17 enhanced Stat5 tyrosine phosphorylation, Stat5 DNA binding, and β‐casein transcription. The expression of DNRasN17 blocked the activation of the Mek–Erk pathway by EGF but did not prevent the phosphorylation of AKT, a measure of activation of the PI‐3‐kinase pathway. Moreover, the expression of DNRasN17 prevented the block to lactogenic differentiation induced by EGF. Stimulation of HC11 cells with prolactin resulted in the association of the SHP2 phosphatase with Stat5, and this association was prevented by DNRasN17 expression. These results demonstrate that in HC11 cells DNRas inhibits the Mek–Erk pathway and enhances lactogenic hormone‐induced differentiation. This occurs, in part, by inhibiting the association of the SHP2 phosphatase with Stat5. Published 2004 Wiley‐Liss, Inc.
An engineered EBV vector expressing human factor VIII and von Willebrand factor in cultured B‐cells
Authors: Basu Utpal , Banerjee Subrata
Published: March 2004

Background

Hemophilia A is a congenital disorder caused by a deficiency of the blood‐clotting factor VIII (FVIII) and is an attractive candidate for gene therapy. Most of the studies have only explored the potential of hepatocytes and muscle cells as the targets for gene transfer. Attempts to transfer the genes into hematopoietic cells have so far been mostly unsuccessful due to inefficiency of most viral vectors to transduce these cells and the supposed inability of the cells to express FVIII.

Methods

We demonstrate the generation of an engineered Epstein‐Barr virus (EBV) vector with a BAC backbone that has the unique capacity to carry either the full‐length FVIII cDNA or its B‐domain‐deleted form; a modified version of the vector that carries B‐domain‐deleted FVIII along with the von Willebrand factor (vWF) cDNA or the reporter gene DsRed2 was also used. All these vectors have been safety modified with viral thymidine kinase cDNA to transduce human B‐cells in culture.

Results

Low‐level expression of FVIII in the order of 5–8 ng FVIIIC/ml were observed in the cells stably transduced with full‐length FVIII, while cells with the B‐domain‐deleted version expressed 8–16 ng FVIIIC/ml. Expression of vWF and B‐domain‐deleted FVIII resulted in a moderate expression of 18–30 ng FVIIIC/ml. Long‐term expression for 12–16 weeks was observed in these cells regardless of selection pressure.

Conclusions

These results support the development of an episomal engineered EBV vector for treatment of hemophilia A using the hematopoietic cells as a target for providing immediate secretion of functionally active product in the circulating bloodstream. Copyright © 2004 John Wiley & Sons, Ltd.
Organ‐specific expression of the lacZ gene controlled by the opsin promoter after intravenous gene administration in adult mice
Authors: Zhu Chunni , Zhang Yun , Zhang Yu‐feng , Yi Li Jian , Boado Ruben J. , Pardridge William M.
Published: March 2004

Background

The tissue‐specific expression of an exogenous gene, under the influence of a tissue‐specific promoter, has been examined in the past with pro‐nuclear injections of the transgene and the development of transgenic mouse models. ‘Adult transgenics’ is possible with the acute expression of an exogenous gene that is administered to adult animals, providing the transgene can be effectively delivered to distant sites following an intravenous administration.

Methods

The organ specificity of exogenous gene expression in adult mice was examined with a bacterial β‐galactosidase (LacZ) expression plasmid under the influence of the bovine rhodopsin gene promoter. The 8‐kb plasmid DNA was delivered to organs following an intravenous administration with the pegylated immunoliposome (PIL) non‐viral gene transfer technology. The PIL carrying the gene was targeted to organs with the rat 8D3 monoclonal antibody (MAb) to the mouse transferrin receptor (TfR).

Results

The rhodopsin/β‐galactosidase gene was expressed widely in both the eye and the brain of adult mice, but was not expressed in peripheral tissues, including liver, spleen, lung, or heart. Ocular expression included the retinal‐pigmented epithelium, the iris, and ciliary body, and brain expression was observed in neuronal structures throughout the cerebrum and cerebellum.

Conclusions

The expression of trans‐genes in adult animals is possible with the PIL non‐viral gene transfer method. The opsin promoter enables tissue‐specific gene expression in the eye, as well as the brain of adult mice, whereas gene expression in peripheral tissues, such as liver or spleen, is not observed. Copyright © 2004 John Wiley & Sons, Ltd.
Wider impacts of microfinance institutions: issues and concepts
Authors: Zohir Sajjad , Matin Imran
Published: March 2004

The paper distinguishes between a ‘wider’ definition of wider impacts (which takes into account feedbacks from impacts to institutional performance) and a ‘narrower’ definition, which does not. In respect of both definitions, the paper sets out a typology of the effects which need to be measured (cultural, economic, social and political) and of the levels at which each of these impacts needs to be assessed (local, regional and national). The purpose is not to set out a blueprint for specific studies but rather to offer a framework which may be useful for guiding the methodology of such studies. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative approach to impact analysis of microfinance programmes in Bangladesh—what have we learned?
Authors: Khalily M. A. Baqui
Published: March 2004

The quantitative impact assessment of microfinance programmes, like the programmes themselves, originated in Bangladesh. This essay reflects on the significance and usefulness for present day researchers of the analytical advances made in Bangladesh since the beginning of the 1990s. Particularly in the area of selection bias, fungibility and the assessment of wider impacts, it argues, those advances are crucial, and need to be borne in mind by all practitioners; but financial sustainability remains an unresolved problem. Copyright © 2004 John Wiley & Sons, Ltd.
The wider impacts of BRAC poverty alleviation programme in Bangladesh
Authors: Chowdhury A. Mushtaque R. , Bhuiya Abbas
Published: March 2004

Over the decades of the 1980s and 90s many poverty alleviation programmes have been implemented in developing countries. Evaluations of such programmes have traditionally looked at their success in increasing the income levels of participants but less at the wider goals of human well‐being. This paper looks at the poverty alleviation programme of BRAC, a large non‐governmental organisation in Bangladesh, and, based on carefully designed studies, presents its impact on selected components of ‘human well‐being’.

This study found better child survival and nutritional status in households served by the programme. Simular impacts were also found in other areas such as expenditure patterns, family planning practices and children's education. The studies also looked at the impact on the rural power structure and found a substantial change in the networking relationship of health providers. The likely influence of ‘selectivity bias’ on the above results is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Mapping cognitions to better understand attitudinal and behavioral responses in appraisal research
Authors: Wright Robert P.
Published: March 2004

Perceptions are important in determining performance appraisal system success. The growing body of research in this area has clearly documented the differences in perceptions between appraisers and appraisees. However, many of these findings are predominately based on aspects of the system in judging its overall effectiveness and rely heavily on self‐report questionnaire responses with weak methodological rigor. Not much is known about the deeper cognitive perceptions of appraisers and appraisees in better explaining their attitudinal and behavioral outcomes. This paper breaks away from conventional questionnaire‐generated perceptions and applies a unique clinical cognitive mapping methodology called the repertory grid technique to elicit the personal constructs of how real respondents perceive appraisal systems based on their real‐life experiences. The method allowed the investigation to go much deeper than past research into the core perceptions that influenced respondents' attitudes and subsequent behaviors. Though the findings showed some commonality in personal constructions of appraisal systems with those found in the literature, new constructs, core perceptual dimensions, and collective cognitive maps were elicited for the very first time, opening up new questions and issues for further research. Implications to theory and practice are also discussed. Copyright © 2004 John Wiley & Sons, Ltd.