bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sudden failure of dual channel pulse generators
Authors: Alesch François 
Published: December 2004

AbstractAn Editor‐Solicited Manufacturer ResposeEditor‐Solicited Manufacturer Respose to this article has been published in Movement Disorders.We report a series of four sudden hardware failures in dual channel pulse generators implanted for chronic stimulation of the subthalamic nucleus in the treatment of Parkinson's disease. In all cases, a sudden and severe deterioration of the patient's neurological condition occurred with symptoms similar to those present before surgery. In all cases, destructive analysis of the generator revealed a fracture of the wire bonds connecting the battery to the hybrid (electronic) part of the pulse generator. This fracture led to repeated Power On Resets, bringing the parameter settings back to default (factory settings). As a cause, we propose that relative movements between the hybrid and the battery led to low cycle fatigue fractures due to insufficient stiffness of the device. That three of four failures occurred when the implant was in the infracostal region makes it likely that the fractures depend on the mechanical stress applied to the device. The efficacy of the therapy resumed immediately after device replacement. As a corrective measure, the manufacturer has added epoxy between both components, increasing significantly the stiffness of the device. © 2004 Movement Disorder Society
Pallidal deep brain stimulation influences both reflexive and voluntary saccades in Huntington's disease
Authors: Fawcett Adrian P. , Moro Elena , Lang Anthony E. , Lozano Andres M. , Hutchison William D. 
Published: December 2004

AbstractDeep brain stimulation (DBS) of the globus pallidus internus (GPi) is being evaluated as a potential new therapy for patients with Huntington's disease (HD). In addition to skeletal movement disorders, HD patients have difficulty initiating voluntary saccades and have difficulty in suppressing rapid saccades toward newly appearing stimuli. We measured several saccade parameters in an HD patient who had marked improvement of clinical symptoms with bilateral GPi DBS to determine whether oculomotor performance improved in parallel with clinical scores. Oculomotor performance was assessed using three testing paradigms: pro‐saccades, anti‐saccades, and memory‐guided saccades. The data from the HD patient was also compared to that of two healthy controls. Pallidal DBS decreased pro‐saccade latency, total movement time, and the number of correctly executed trials, as well as increasing saccade gain. Memory–saccade performance was negatively affected with stimulation: saccade gain decreased, latency increased, and the patient's ability to suppress unwanted saccades decreased with stimulation. Our data demonstrate a task‐specific improvement of oculomotor deficits in this HD patient with pallidal DBS, supporting a role of GPi in oculomotor control. © 2004 Movement Disorder Society
Trial of subtherapeutic pergolide in de novo Parkinson's disease
Authors: Grosset Katherine , Grosset Donald , Lees Andrew ,   Parkinson's Disease Research Group of the United Kingdom
Published: December 2004

AbstractThe effect of pergolide 25 μg twice daily on levodopa initiation was assessed in a randomized, placebo‐controlled, parallel group, double‐blind multicenter trial in 106 untreated early Parkinson's disease patients. The primary endpoint of mean time until levodopa was 520 days (95% confidence interval [CI], 422–618 days) for pergolide versus 434 days (95% CI, 358–609 days) for placebo. However, this increase of 86 days for pergolide was not statistically significant. The wash‐in effect of pergolide was significant at 6 weeks (change in mean Unified Parkinson's Disease Rating Scale [UPDRS] 2 and 3 was −0.1 [95% CI, −1.4 to 1.3] for pergolide vs. 2.2 [95% CI, 1.1–3.3] for placebo). At termination, the change from baseline in mean UPDRS 2 and 3 score was 11.4 (95% CI, 8.8–14) for pergolide and 14.6 (95% CI, 12–17.2) for placebo (P = 0.08). There was no significant change in UPDRS 2 and 3 for the 83 patients achieving the planned 4‐week washout at termination (pergolide 1.2 [95% CI, −0.8 to 3.2] vs. placebo 0.0 [95% CI, −1.6 to 1.6]. Adverse events were infrequent and occurred equally for pergolide and placebo. The study shows no evidence of a neuroprotective effect but indicates a mild symptomatic benefit from pergolide at a dose normally considered subtherapeutic. © 2004 Movement Disorder Society
Melt‐extensional properties and orientation behaviors of polypropylene‐layered silicate nanocomposites
Authors: Koo Chong Min , Kim Jong Hyun , Wang Ki Hyun , Chung In Jae 
Published: December 2004

AbstractPolypropylene‐layered silicate nanocomposites consisting of three components—pure polypropylene, maleated polypropylene, and organically modified silicate—were prepared by the melt‐intercalation method to investigate melt‐extensional properties such as melt strength, neck‐in test, and orientation behavior. The nanocomposites showed an enhanced tensile modulus, enhanced storage modulus, much enhanced melt tension, and reduced neck‐in during the melt processing as compared with neat polymer. The uniaxial drawing induced the silicate surface to align parallel to the sheet surface. The c and a* axes of the polypropylene crystals were bimodally oriented to the flow direction, and the b axes were oriented to the thickness direction. The bimodal orientation of the polypropylene crystal was enhanced with the concentration of silicates. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 158–167, 2005
Syntheses, Crystal Structures, and Antibacterial Activities of Four Schiff Base Complexes of Copper and Zinc
Authors: You Zhong‐Lu , Zhu Hai‐Liang 
Published: December 2004

AbstractFour Schiff base complexes, [Cu2(L1)2(μ‐NCS)2] (1), [Cu2(L2)2(μ‐N3)2] (2), Cu[Cu(CH3COO)(L3)]2 (3), and [Zn{Zn(C3H4N2)(L3)}2(NO3)](NO3) (4) (where L1 = 2‐[(pyridin‐2‐ylmethylimino)methyl]phenol, L2 = 1‐[(pyridin‐2‐ylmethylimino)methyl]naphthalen‐2‐ol, and L3 = bis(salicylidene)‐1, 3‐propanediamine), were synthesized and characterized by elemental analyses, infrared spectroscopy, and single crystal X‐ray determinations. Both 1 and 2 are structurally similar di‐nuclear complexes, which are located at crystallographic inversion centers (with the center of the central Cu2N2 ring). In 1, each copper atom has a slightly distorted square pyramidal configuration, coordinated by two nitrogen atoms and one oxygen atom from L1 and another two terminal nitrogen atoms from two bridging thiocyanate anions. The Cu···Cu separation is 3.466(3) Å. The structure of 2 is similar to that of 1, with Cu···Cu separation of 3.368(2) Å. Both 3 and 4 are linear tri‐nuclear complexes. In 3, the central Cu2+ ion is located on an inversion centre and has a distorted octahedral coordination involving four bridging O atoms from two Schiff base ligands (L3) in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal Cu2+ ions is irregular‐square pyramidal, with two O and two N atoms of L3 in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal Cu2+ ions are mutually trans. The Cu···Cu separation is 3.009(3) Å. In 4, the coordination configuration of the central and the terminal zinc atoms are similar to that of the 3, with Zn···Zn separation of 3.153(4) Å. The three Schiff bases and the corresponding three copper complexes exhibit good antibacterial properties, while the zinc complex 4 has nearly no.
Synthesis and Crystal Structures of α‐ and β‐Mg2[(UO2)3(SeO4)5](H2O)16
Authors: Krivovichev Sergey V. , Kahlenberg Volker 
Published: December 2004

AbstractSingle crystals of α‐ and β‐Mg2[(UO2)3(SeO4)5](H2O)16 have been synthesized by evaporation from an aqueous solution of the ionic components. The structure of α‐Mg2[(UO2)3(SeO4)5](H2O)16 (monoclinic, C2/c, a = 19.544(3), b = 10.4783(11), c = 18.020(3) Å, β = 91.352(12)°, V = 3689.3(9) Å3) has been solved by direct methods and refined to R1 = 0.048 on the basis of 4338 unique observed reflections. The structure of β‐Mg2[(UO2)3(SeO4)5](H2O)16 (orthorhombic, Pbcm, a = 10.3807(7), b = 22.2341(19), c = 33.739(5) Å, V = 7787.2(14) Å3) has been solved by direct methods and refined to R1 = 0.107 on the basis of 3621 unique observed reflections. The structures of α‐ and β‐Mg2[(UO2)3(SeO4)5](H2O)16 are based upon sheets with the chemical composition [(UO2)3(SeO4)5]4‐. The sheets are formed by corner sharing between pentagonal bipyramids [UO7]8‐ and SeO42‐ tetrahedra. In the α‐modification, the [(UO2)3(SeO4)5]4‐ sheets are more or less planar and run parallel to (001). In the structure of the β‐modification, the uranyl selenate sheets are strongly corrugated and oriented parallel to (010). The [Mg(H2O)6]2+ polyhedra reside in the interlayers and provide three‐dimensional linkage of the uranyl selenate sheets via hydrogen bonding. In addition to H2O groups attached to Mg2+ cations, both structures also contain H2O molecules that are not bonded to any cation. The [(UO2)3(SeO4)5]4‐ sheets in the structures of α‐ and β‐Mg2[(UO2)3(SeO4)5](H2O)16 represent two different structural isomers. The sequences of the orientations of the tetrahedra within the sheets can be described by their orientational matrices with their shortened forms (ddudd□/uu□uud) and (dd□dd□uu□uu□/uuduumdduddm) for α‐ and β‐Mg2[(UO2)3(SeO4)5](H2O)16, respectively. A short review on the isomerism of [(UO2)3(TO4)5]4‐ sheets (T = S, Cr, Se, Mo) is given.
Synthese, Strukturen, NMR‐ und EPR‐spektroskopische Untersuchungen an Übergangsmetallkomplexen monofluorsubstituierter Acylselenoharnstoffliganden
Authors: Kampf Michael , Richter Rainer , Hennig Lothar , Eidner Andreas , Baldamus Jens , Kirmse Reinhard 
Published: December 2004

AbstractDie Synthesen und die Kristallstrukturen des Liganden N, N‐Diethyl‐N′‐(2‐fluor)benzoylselenoharnstoff HEt2mfbsu und dessen NiII‐ und ZnII‐Komplexen sowie des Liganden N, N‐Diisobutyl‐N′‐(2‐fluor)benzoylselenoharnstoff HBui2mfbsu und dessen NiII‐ und PdII‐Komplexen werden berichtet. Die Liganden koordinieren zweizähnig unter Bildung von Bischelaten. Der PdII‐ und die NiII‐Komplexe sind planar koordiniert und cis‐konfiguriert; [ZnII(Et2mfbsu)2] ist tetraedrisch koordiniert. Die Struktur des ebenfalls erhaltenen Bis[diisobutylamino‐(2‐fluorbenzoylimino)methyl]diselenids wird vorgestellt. Die CuII‐Komplexe beider Liganden konnten nicht isoliert werden. EPR‐Untersuchungen an den als Öle anfallenden Komplexen bestätigen jedoch eindeutig das Vorliegen der CuII‐Bischelate. Detaillierte NMR‐spektroskopische Untersuchungen ‐ 1H‐, 13C‐ und 19F‐COSY, HMBC und HMQC ‐ an [MII(Et2mfbsu)2] (M = NiII, ZnII) erlauben eine exakte Zuordnung aller Signale zu den magnetisch aktiven Kernen der Komplexe.
Complex Tellurium Salts with Supramolecular Bidimensional Lattices: Synthesis and X‐ray Characterization of (2‐Br‐C5NH5)2[TeX6] (X = Cl, Br)
Authors: Fernandes Ramão Marceli , de Oliveira Gelson Manzoni , Schulz Lang Ernesto , Vázquez‐López Ezequiel M. 
Published: December 2004

AbstractThe reaction of tellurium(IV) tetrahalides with hydrochloric and hydrobromic acid leads to the formation of (H3O)2[TeX6], which reacts subsequently with (2‐Br‐C5NH5)+X‐ to afford (2‐Br‐C5NH5)2[TeCl6] (1) and (2‐Br‐C5NH5)2[TeBr6] (2). The structure of the complex salts were analysed by X‐ray diffractometry affording the centrosymmetric space groups P21/n (monoclinic, 1) and P1¯ (triclinic, 2). Interionic hydrogen bondings hold their lattices in bidimensional supramolecular arrays not yet described in the literature. The lone electron pair of the AX6E‐system of the hexahalotellurates [TeX6]2‐ (X = Cl, Br) seems to be fully delocalized since only small octahedral deviations were observed for the anionic species. The structures of the title compounds were refined with the Te atoms occupying sites with full point symmetry, approximately m3¯m. In both cases the Te atoms enclose centers of inversion and the octahedrally dynamic structures are enforced and stabilized along the supramolecular lattices by the crystal field of the 2‐Br‐pyridinium cations.
Cyclic Iminoboranes: Analogues of Cycloalkynes
Authors: Münster Jochen , Paetzold Peter , Schröder Ernst , Schwan Heinrich , von Bennigsen‐Mackiewicz Theo 
Published: December 2004

Abstract1‐Azido‐ and 1‐[trimethylsilyl(trimethylsilyloxy)]boracycloalkanes, (‐Y‐BX‐) [X = N3 (2), N(OSiMe3)SiMe3 (3), Y = alkanediyl], were synthesized from the corresponding chloroboranes [X = Cl (1)]. The following alkanediyl ring fragments were considered: Y = ‐CH2‐CHMe‐CH2‐CH2‐ (a), 1, 5‐cyclooctanediyl (b), ‐(CH2)6‐ (c), ‐(CH2)7‐ (d), ‐CMe2‐(CH2)6‐ (e), ‐C(‐CMe2‐CH2‐)‐(CH2)6‐ (f). The thermal elimination of N2 (from 2) or (SiMe3)2O (from 3) is accompanied by the migration of one of the two alkanediyl ends from boron to nitrogen under ring expansion to give the cyclic iminoboranes 4. Formed in solution, the iminoboranes react immediately with undecomposed starting material 2 or 3 under formation of the products 5 or 6 by azidoboration or aminoboration, respectively, of the BN multiple bond. The temperature for the decomposition of 2 depends on the ring size: the five‐membered ring compound 2a and the bicyclic six‐membered ring compound 2b decompose beneath 0 °C, the seven‐ and eight‐membered ring compounds 2c and 2d in boiling hexane and toluene, respectively, whereas the eight‐membered ring compounds 2e and 2f are decomposed in solution above 100 °C so slowly that only unidentified polymers are found. The boranes 3a and 3b, stable at room temperature, afford a temperature of 80 °C for decomposition in solution. The azidoboranes 2c‐f can be transported into the gas‐phase without decomposition and can be thermolyzed there at 270‐285 °C. The cyclic iminoboranes 4c‐e, formed in the hot tube, were condensed at ‐196 °C, but thereafter not characterized, because they either cyclotrimerized (4c, d) or cyclodimerized (4e, e′; two isomers depending on which end of the 1, 1‐dimethylheptamethylene unit migrates) beneath ‐60 °C under formation of the corresponding borazines 10c, d or of the diazadiboretidine isomer mixture 9e, e′, respectively; the spirocyclic borane 2f gives a mixture of unidentified products on gas‐phase thermolysis. The iminoboranes 4e, e′ can be trapped by ethyloboration with BEt3 giving the products 8e, e′. The acyclic azidoborane R(Me)BN3 (2g; R = 1‐methylcycloheptyl), formed after the ring‐contracting rearrangement of a boracyclooctane derivative, gives the isolated and characterized mixture of the acyclic iminoboranes MeB≡NR (4g) and RB≡NMe (4g′) upon gas‐phase thermolysis; the stabilization of 4g, g′ gives the Dewar borazines 11g and 11g′.
Synthese und Struktur von (PPh4)3[Re2NCl10]
Authors: Schwarz Simon , Strähle Joachim 
Published: December 2004

AbstractDer Rhenium(V)nitrido‐Komplex (PPh4)3[Re2NCl10] (1) entsteht bei der Reaktion von (PPh4)[ReNCl4] mit 1, 3‐Dioxan‐(2‐ylmethyl)diphenylphosphan in CH2Cl2/CH3CN in Form orangeroter, solvathaltiger Kristalle. Er kristallisiert als 1·2CH2Cl2 in der triklinen Raumgruppe P1¯ mit a = 1210, 7(2); b = 1232, 5(1); c = 2756, 3(5) pm; α = 99, 68(1)°; β = 100, 24(1)°; γ = 98, 59(1)° und Z = 2. In der Kristallstruktur liegen zwei symmetrieunabhängige, zentrosymmetrische Komplexanionen [Re2NCl10]3‐ mit symmetrischen Nitridobrücken Re=N=Re und Abständen Re(1) ‐ N(1) = 181, 34(5) und Re(2) ‐ N(2) = 181, 51(4) pm vor.
Interplay of Electronic Structure and Bulk Properties in 2D and 3D Ternary Carbonitrides from First Principles
Authors: Betranhandy E. , Matar Samir F. , El‐Kfoury Ch. , Weihrich R. , Etourneau J. 
Published: December 2004

AbstractThe changes in electronic structure and hardness as inferred from the bulk modulus are investigated for model structures of ternary compounds XC3N3 (X = B, Al, P, As, Ga) within the framework of density functional theory (DFT). The optimisations of the proposed two‐ (2D) and three‐dimensional (3D) structures and the calculations of the bulk moduli are performed by a pseudo potential method. The electronic structures are calculated with the augmented sphere wave method (ASW). The obtained hardness for 2D BC3N3 system (B0 ∼ 220 GPa) points to a magnitude close to that of graphitic C3N4. For heavier X atoms it decreases rapidly. This is equally observed for the 3D systems examined in the β‐C3N4 structure for which B0(β‐BC3N3) amounts to ∼330 GPa. Within the magnitude of the well known hard material cubic BN, the BC3N3 phases can be predicted as candidates for ultra hard materials. The electronic effect induced by the chemical nature of the X substitutional was examined according to its position in the periodic table i.e. XIII or XV. Both, band structures and the electron localisation function (ELF) were used for this analysis. The ELF plots show a decreasing covalency with heavier X‐atoms. Potential applications of the devised systems are proposed such as dopings with atoms (Li, rare gas) and molecules (N2).
Computational Design of Hybrid Frameworks: Structure and Energetics of Two Me3OF3{‐O2C‐C6H4‐CO2‐}3 Metal‐Dicarboxylate Polymorphs, MIL‐hypo‐1 and MIL‐hypo‐2
Authors: Mellot‐Draznieks C. , Dutour Julien , Férey Gérard 
Published: December 2004

AbstractThe present paper aims at exploring the candidate hybrid structures of the Cr/trimesic acid system by assembling pre‐defined hybrid building‐blocks in direct space. Two possible hybrid building‐blocks were identified where the connection of the 1, 4 BDC molecules to an inorganic metal‐containing trimer forms a large supertetrahedron (ST) or alternatively a large supercube (SC). From existing topologies derived from the space filling packing of corner‐sharing cubes and tetrahedra, two candidates hybrid crystal structures were constructed. Lattice energy minimizations were performed on each candidate structure, as a preliminary step towards the estimation of their relative stabilities. This work further illustrates the computational design of very open hybrid frameworks using the concept of pre‐defined building blocks and their assembly in 3D space.
Chondrodysplasia punctata with a mild clinical course
Authors: Nuoffer J. M. , Pfammatter J. P. , Spahr A. , Toplak H. , Wanders R. J. A. , Schutgens R. B. H. , Wiesmann U. N. 
Published: December 2004

SummaryWe report a 7‐year‐old patient with chondrodysplasia punctata but without rhizomelia. He was born with typical clinical and radiological symptoms of this disease. He developed slowly with considerable psychomotor retardation but improved later, gaining some speech and psychosocial contacts. Joint contractures and bilateral cataracts are still major problems.De novo plasmalogen synthesis in fibroblasts was greatly reduced and DHAP‐AT activity was at the lower limit of controls. Peroxisomal thiolase was present in its precursor form only. Membrane fluidity (measured by TMA‐DPH fluorescence anisotropy) was increased in erythrocyte ghosts and in lymphocytes. Plasma phytanic acid concentration was elevated 5‐fold. The patient represents a mild clinical course of chondrodysplasia punctata, resembling Conradi‐Hünermann syndrome, but biochemically he has the typical peroxisomal dysfunction of rhizomelic chondrodysplasia punctata except for a high residual activity of DHAP‐AT.
The N370S mutation in the glucocerebrosidase gene of Portuguese type 1 Gaucher patients: Linkage to the PvuII polymorphism
Authors: Lacerda L. , Amaral O. , Pinto R. , Aerts J. , Sá Miranda M. C. 
Published: December 2004

SummaryThe mutation N370S accounts for 63% of the mutated glucocerebrosidase alleles of Portuguese type 1 Gaucher patients. It has been shown previously that this mutation is linked to the Pv1.1− form of the PvuII polymorphism and suggested that the N370S mutation in glucocerebrosidase alleles has an Ashkenazi Jewish origin. We have found that in Portuguese type 1 Gaucher patients this mutation is also invariably associated with the Pv1.1− haplotype, despite the fact that there is no evidence of Ashkenazi Jewish background in this population.
Sjögren‐Larsson syndrome: Nuclear magnetic resonance imaging of the brain in a 4‐year‐old boy
Authors: Di Rocco M. , Filocamo M. , Tortori‐Donati P. , Veneselli E. , Borrone C. , Rizzo W. B. 
Published: December 2004

SummaryMagnetic resonance imaging of the brain of a 4‐year‐old patient with fatty alcohol: NAD+ oxidoreductase deficiency (Sjögren‐Larsson syndrome) showed a severe leukodystrophy.
Ser95, Asn97, and Thr78 are important for the catalytic function of porcine NADP‐dependent isocitrate dehydrogenase
Authors: Kim Tae‐Kang , Colman Roberta F. 
Published: December 2004

AbstractThe mammalian mitochondrial NADP‐dependent isocitrate dehydrogenase is a citric acid cycle enzyme and an important contributor to cellular defense against oxidative stress. The Mn2+‐isocitrate complex of the porcine enzyme was recently crystallized; its structure indicates that Ser95, Asn97, and Thr78 are within hydrogen‐bonding distance of the γ‐carboxylate of enzyme‐bound isocitrate. We used site‐directed mutagenesis to replace each of these residues by Ala and Asp. The wild‐type and mutant enzymes were expressed in Escherichia coli and purified to homogeneity. All the enzymes retain their native dimeric structures and secondary structures as monitored by native gel electrophoresis and circular dichroism, respectively. Vmax of the three alanine mutants is decreased to 24%–38% that of wild‐type enzyme, with further decreases in the aspartate mutants. For T78A and S95A mutants, the major changes are the 10‐ to 100‐fold increase in the Km values for isocitrate and Mn2+. The results suggest that Thr78 and Ser95 function to strengthen the enzyme's affinity for Mn2+‐isocitrate by hydrogen bonding to the γ‐carboxylate of isocitrate. For the Asn97 mutants, the Km values are much less affected. The major change in the N97A mutant is the increase in pKa of the ionizable metal‐liganded hydroxyl of enzyme‐bound isocitrate from 5.23 in wild type to 6.23 in the mutant enzyme. The hydrogen bond between Asn97 and the γ‐carboxylate of isocitrate may position the substrate to promote a favorable lowering of the pK of the enzyme–isocitrate complex. Thus, Thr78, Ser95, and Asn97 perform important but distinguishable roles in catalysis by porcine NADP‐specific isocitrate dehydrogenase.
Amyloid accomplices and enforcers
Authors: Alexandrescu Andrei T. 
Published: December 2004

AbstractAmyloid‐related diseases are often ascribed to protein “misfolding.” Yet in the absence of high‐resolution structures for mature fibrils or intermediates, the connection between the mechanism of amyloid formation and protein folding remains tenuous. The simplistic view of amyloid fibrillogenesis as a homogeneous self‐assembly process is being increasingly challenged by observations that amyloids interact with a variety of cofactors including metals, glycosaminoglycans, glycoproteins such as serum amyloid P and apolipo‐protein E, and constituents of basement membranes such as perlecan, laminin, and agrin. These “pathological chaperones” have effects that range from mediating the rate of amyloid fibril formation to increasing the stability of amyloid deposits, and may contribute to amyloid toxicity. An increasing appreciation of the role of accessory molecules in amyloid etiology has paved the way to novel diagnostics and therapeutic strategies.