bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atypical dementia associated with a novel presenilin‐2 mutation
Authors: Binetti Giuliano , Signorini Simona , Squitti Rosanna , Alberici Antonella , Benussi Luisa , Cassetta Emanuele , Battista Frisoni Giovanni , Barbiero Laura , Feudatari Enrica , Nicosia Francesca , Testa Cristina , Zanetti Orazio , Gennarelli Massimo , Perani Daniela , Anchisi Davide , Ghidoni Roberta , Rossini Paolo Maria 
Published: December 2003

AbstractWe describe an Italian pedigree with hereditary dementia associated with a novel T122R mutation in the presenilin‐2 gene (PSEN2). The clinical history, symptom presentation, and structural neuroimaging were consistent with an atypical form of dementia. Disease expression varied within family members. One in a pair of mutated monozygotic twins had evident signs of disease, whereas the other did not, even if her functional neuroimaging investigations, cerebrospinal fluid levels of Aβ1‐42, and Tau protein were able to provide markers for future disease development. These observations suggest the importance of still unknown biological and perhaps environmental factors in the disease determination.
Amyloid β protein toxicity mediated by the formation of amyloid‐β protein precursor complexes
Authors: Lu Daniel C. , Shaked Gideon M. , Masliah Eliezer , Bredesen Dale E. , Koo Edward H. 
Published: December 2003

AbstractThe amyloid‐β protein precursor, a type 1 transmembrane protein, gives rise to the amyloid β‐protein, a neurotoxic peptide postulated to be involved in the pathogenesis of Alzheimer's disease. Here, we show that soluble amyloid β protein accelerates amyloid precursor protein complex formation, a process that contributes to neuronal cell death. The mechanism of cell death involves the recruitment of caspase‐8 to the complex, followed by intracytoplasmic caspase cleavage of amyloid precursor protein. In vivo, the levels of soluble amyloid β protein correlated with caspase‐cleaved fragments of the amyloid precursor protein in brains of Alzheimer's disease subjects. These findings suggest that soluble amyloid β protein–induced multimerization of the amyloid precursor protein may be another mechanism by which amyloid β protein contributes to synapse loss and neuronal cell death seen in Alzheimer's disease. Ann Neurol 2003;54:781–789
The release of tumor necrosis factor–α is associated with ischemic tolerance in human stroke
Authors: Castillo José , Moro María Ángeles , Blanco Miguel , Leira Rogelio , Serena Joaquín , Lizasoain Ignacio , Dávalos Antonio 
Published: December 2003

AbstractTumor necrosis factor (TNF)–α overexpression has been related to experimental ischemic tolerance when transient ischemia precedes cerebral infarction. We investigated TNF‐α and interleukin (IL)–6 plasma concentrations in 283 patients with an acute stroke within 24 hours after symptom onset. An ipsilateral transient ischemic attack (TIA) within 72 hours before stroke was recorded in 38 patients. The infarct volume measured on computed tomography on days 4 to 7 and the frequency of poor outcome (Barthel Index score < 85) at 3 months were significantly lower in patients with prior TIA. Plasma concentrations of TNF‐α were higher (42.5 ± 9.9 vs 13.1 ± 6.4pg/ml, p < 0.0001) and IL‐6 levels were lower (10.1 ± 6.2 vs 28.3 ± 17.3pg/ml, p < 0.0001) in patients with prior TIA. A new variable termed TNF‐α/IL‐6 index was considered positive when TNF‐α was greater than 30pg/ml and IL‐6 was less than 30pg/ml. Positive TNF‐α/IL‐6 index was found in 92% of patients with prior TIA and in 1% of those without. TNF‐α/IL‐6 index (p = 0.0003) and TIA (p = 0.0001) were associated with good outcome in logistic regression analysis after adjusting for potential confounding factors. Ischemic tolerance in acute stroke is associated with increased plasma levels of TNF‐α in the presence of reduced concentrations of IL‐6. Ann Neurol 2003;54:811–819
A locus for complicated hereditary spastic paraplegia maps to chromosome 1q24‐q32
Authors: Blumen Sergiu C. , Bevan Simon , Abu‐Mouch Saif , Negus David , Kahana Michael , Inzelberg Rifka , Mazarib Aziz , Mahamid Ahmad , Carasso Ralph L. , Slor Hanoch , Withers David , Nisipeanu Puiu , Navon Ruth , Reid Evan 
Published: December 2003

AbstractWe updated the clinical features of a consanguineous Arab Israeli family, in which four of seven children were affected by spastic paraplegia complicated by skin pigmentary abnormalities. A genomewide linkage screen performed for the family identified a new locus (SPG23) for this form of hereditary spastic paraplegia, in an approximately 25cM region of chromosome 1q24‐q32, with a peak logarithm of odds score of 3.05. Ann Neurol 2003;54:796–803
Diagnostic value of electromyography and muscle biopsy in arthrogryposis multiplex congenita
Authors: Kang Peter B. , Lidov Hart G. W. , David William S. , Torres Alcy , Anthony Douglas C. , Jones H. Royden , Darras Basil T. 
Published: December 2003

AbstractArthrogryposis multiplex congenita (AMC), a clinical syndrome characterized by multiple congenital joint contractures, frequently is caused by lesions in the peripheral nervous system. Two standard tests for the evaluation of the motor unit are nerve conduction studies/electromyography (NCS/EMG) and muscle biopsy. We reviewed the diagnostic value of these two studies in the evaluation of AMC over a 23‐year period, analyzing 38 patients with AMC who had NCS/EMG, muscle biopsy, or both. Final diagnoses were classified as neurogenic (8 patients), myopathic (10 patients), “other” (12 patients), or unknown (8 patients). Neither test alone had consistently high sensitivities, positive predictive values, or specificities. However, when NCS/EMG and muscle biopsy were concordant for neurogenic or myopathic findings, they were more accurate than either test alone, especially for neurogenic diseases. Test results were most commonly discordant in patients with “other” or unknown diagnoses. These findings suggest that when the clinical evaluation indicates a specific syndromic, developmental, or exogenous cause, NCS/EMG and muscle biopsy are not helpful and may not need to be performed. When the history, examination, and genetic evaluation are unrevealing, NCS/EMG and muscle biopsy together provide valuable diagnostic information.
Vascular parkinsonism in moyamoya: Microvascular biopsy and imaging correlates
Authors: Tan Eng‐King , Chan Ling‐Ling , Yu Gui Xia , Rumpel Helmut , Wilder‐Smith Einar , Wong Meng‐Cheng 
Published: December 2003

AbstractWe highlight the first case to our knowledge of vascular parkinsonism with angiographic moyamoya and functional imaging correlates. In addition, transmission electron microscopy of the cutaneous vasculature revealed the mean smooth muscle cell layer of the terminal arterioles to be significantly higher compared with ischemic stroke patients classified by vascular risk factors. Smooth muscle cell thickness was also greater in those with small vessel and large vessel strokes compared with cardioembolic strokes. The marked cutaneous arteriolar smooth muscle cell hypertrophy may be a useful surrogate marker for those at risk of developing angiographic moyamoya.
Die Rolle von Radikalen bei metallvermittelten Oxygenierungen
Authors: Limberg Christian 
Published: December 2003

AbstractMetallvermittelte Oxofunktionalisierungen organischer Substrate sind von fundamentaler Bedeutung – in der Natur genauso wie in Hochschul‐ und Industrielaboratorien. Ungeachtet dessen sind die Mechanismen dieser Reaktionen rätselhaft geblieben, und nur wenige Prozesse werden im Detail verstanden. Dank intensiver Forschung konnte der Wissensstand in den letzten Jahren aber erheblich verbessert werden: So wurde gezeigt, dass viele Oxygenierungen über Radikalintermediate verlaufen – mitunter auch dann, wenn eine vergleichsweise hohe Selektivität Gegenteiliges vermuten lässt. Das zeigen Beispiele aus den unterschiedlichsten Bereichen: von molekularen Metalloxokomplexen, gasförmigen und matrixisolierten Spezies über das Reaktionsverhalten von Metalloenzymen bis hin zu Prozessen an Festkörperoberflächen. Der vorliegende Aufsatz beleuchtet die Vielfalt dieser Systeme und vermittelt einen Überblick über allgemein gültige Reaktionsmuster und Prinzipien sowie einige noch ungelöste Probleme.
The Role of Radicals in Metal‐Assisted Oxygenation Reactions
Authors: Limberg Christian 
Published: December 2003

AbstractThe oxo‐functionalization of organic substrates with the aid of metal oxo moieties is of fundamental importance not only in nature but also in academic and industrial research. Nevertheless the corresponding reaction mechanisms remain among the most enigmatic in chemistry and few of them are understood in detail. Recent research efforts have resulted in significantly improved information: In the cases of many oxygenation reactions evidence has been provided for the occurrence radical intermediates, even though the high selectivity observed suggests to a different mechanism. Examples stem from various areas of chemistry and include processes involving molecular metal oxo complexes, gas‐phase and matrix‐isolated species, metalloenzymes, and solid‐state oxide surfaces. This Review treats this seemingly wide variety of systems with the aim of providing an overview of common reactivity patterns and principles, as well as open problems.
High‐conversion catalytic chain transfer polymerization of methyl methacrylate
Authors: Pierik S. C. J. , Herk A. M. van 
Published: December 2003

AbstractIn this work the effects of conversion on the apparent catalyst activity in the catalytic chain transfer polymerization of methyl methacrylate are reported. Several mechanisms are discussed that may explain the experimental observations. The discussion is supported with computer simulations using Predici software. It is shown that the experimental decrease in weight average molecular weight with conversion is smaller than the decrease obtained in simulations. The most likely cause for this discrepancy is slow catalyst deactivation. The half‐life of CoBF under the reported conditions was determined to be about 10 h. Furthermore, the effect of acetic acid (HAc) and benzoyl peroxide (BPO) on the evolution of the molecular weight distribution is investigated. Both HAc and BPO enhance catalyst deactivation. For HAc, catalyst deactivation scales with the square root of its concentration. BPO‐ enhanced deactivation depends linearly on its concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1375–1388, 2004
Degradation of polyethylene during extrusion. II. Degradation of low‐density polyethylene, linear low‐density polyethylene, and high‐density polyethylene in film extrusion
Authors: Andersson Thorbjörn , Stålbom Berit , Wesslén Bengt 
Published: December 2003

AbstractThe degradation of different polyethylenes—low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and high‐density polyethylene (HDPE)—with and without antioxidants and at different oxygen concentrations in the polymer granulates, have been studied in extrusion coating processing. The degradation was followed by online rheometry, size exclusion chromatography, surface oxidation index measurements, and gas chromatography–mass spectrometry. The degradations start in the extruder where primary radicals are formed, which are subject to the auto‐oxidation when oxygen is present. In the extruder, crosslinking or chain scissions reactions are dominating at low and high melt temperatures, respectively, for LDPE, and chain scission is overall dominating for the more linear LLDPE and HDPE resins. Additives such as antioxidants react with primary radicals formed in the melt. Degradation taking place in the film between the die orifice, and the quenching point is mainly related to the exposure time to air oxygen. Melt temperatures above 280°C give a dominating surface oxidation, which increases with the exposure time to air between die orifice and quenching too. A number of degradation products were identified—for example, aldehydes and organic acids—which were present in homologous series. The total amount of aldehydes and acids for each number of chain carbon atoms were appeared in the order of C5>C4>C6>C7≫C2 for LDPE, C5>C6>C4>C7≫C2 for LLDPE, and C5>C6>C7>C4≫C2 for HDPE. The total amounts of oxidized compounds presented in the films were related to the processing conditions. Polymer melts exposed to oxygen at the highest temperatures and longest times showed the presence dialdehydes, in addition to the aldehydes and acids. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1525–1537, 2004
Blends of plasticized poly(vinyl chloride) and waste flexible poly(vinyl chloride) with waste nitrile rubber powder
Authors: Ghaisas S. S. , Kale D. D. , Kim J. G. , Jo B. W. 
Published: December 2003

AbstractBlends of poly(vinyl chloride) (PVC) with varying contents of plasticizer and finely ground powder of waste nitrile rubber rollers were prepared over a wide range of rubber contents through high‐temperature blending. The effects of rubber and plasticizer (dioctyl phthalate) content on the tensile strength, percentage elongation, impact properties, hardness, abrasion resistance, flexural crack resistance, limiting oxygen index (LOI), electrical properties, and breakdown voltage were studied. The percentage elongation, flexural crack resistance, and impact strength of blends increased considerably over those of PVC. The waste rubber had a plasticizing effect. Blends of waste plasticized PVC and waste nitrile rubber showed promising properties. The electrical properties and LOI decreased with increasing rubber and plasticizer content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1552–1558, 2004
Lifetime assessment of epoxies by the kinetics of thermal degradation
Authors: Stutz Herbert 
Published: December 2003

AbstractThe kinetics of thermal degradation of 4,4′‐diaminodiphenylsulfone (DDS)‐cured glycidylethers (DGBA) and glycidylamines (TGDDM) have been studied by isothermal annealing. Thermal degradation proceeds via first‐order kinetics with activation energies of 138 (DGBA/DDS) and 95 kJ/mol (TGDDM/DDS). From these data the temperature‐dependent lifetime can be calculated. Based on the heat distortion temperature and 20 years' service as criteria, the upper service temperature is found to be around 115–120°C. In spite of the different activation energies and bond stabilities, only marginal differences in the upper allowed service temperatures between these resins were found. Only slight improvements can be expected by optimizing the cure conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1881–1886, 2004
Miscibility and specific interactions in blends of poly(vinyl phenyl ketone hydrogenated) with poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Maldonado‐Santoyo M. , Nuño‐Donlucas S. M. , Cesteros L. C. , Katime I. 
Published: December 2003

AbstractThe miscibility behavior of poly(vinyl phenyl ketone hydrogenated) (PVPhKH) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) are studied by differential scanning calorimetry, thermomechanical analysis, and FTIR spectroscopy. Two miscibility windows between 10 to 40 and 60 to 90 wt % PPO are detected. Only the blend with 50 wt % PPO is immiscible. The best fit of the Gordon–Taylor equation of the experimental glass‐transition temperatures for miscible PVPhKH/PPO blends is shown. A study by FTIR spectroscopy suggests that hydrogen bonding interactions are formed between the hydroxyl groups of PVPhKH and the ether groups of PPO. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1887–1892, 2004
Surface free‐energy analysis of poly(N‐vinyl‐2‐pyrrolidone–crotonic acid) copolymers prepared by γ‐ray‐induced polymerization technique
Authors: Çaykara Tuncer , Yerlikaya Zekeriya , Kantoğlu Ömer 
Published: December 2003

AbstractPure poly(N‐vinyl‐2‐pyrrolidone) (PVP) and P(VP–crotonic acid) [P(VP/CrA)] copolymers with different CrA contents were prepared by the γ‐ray‐induced polymerization technique. The change in the surface free energy of the copolymers was investigated using the Van Oss–Good contact angle evaluation methodology in order to estimate their wettability properties. The apolar Lifshitz–van der Waals component (γ) and the electron donor component (γ) of the PVP network were calculated as 27.6 and 56.5 mN m−1, respectively. In this case, the surface of the PVP network had a basic character (electron donor). By contrast, the γ component of P(VP/CrA) copolymers increased and then remained almost constant with increasing CrA content. In addition, the surface of these copolymers changed from a basic character (γ = 56.5 mN m−1) to an acidic character (γ = 0.07 mN m−1) with increasing CrA contents in the copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1893–1897, 2004
Rheological behavior of reactive blending of epoxidized natural rubber with cassava starch and epoxidized natural rubber with natural rubber and cassava starch
Authors: Nakason C. , Kaesaman A. , Sainamsai W. , Kiatkamjonwong S. 
Published: December 2003

AbstractEpoxidized natural rubbers (ENR‐25 and ENR‐45) were prepared using the performic epoxidation method. Two‐component (ENR–cassava starch) and three‐component (ENR–NR–cassava starch) blends were prepared. ENR‐25 and ENR‐45 were blended with various quantities of gelatinized cassava starch in the latex state. The pure ENR exhibited lower shear stress and shear viscosity than those of the blends with cassava starch. Furthermore, the shear stress and shear viscosity were increased with an increase in the cassava starch concentration. The chemical interaction between the epoxide groups in the ENR and the hydroxyl groups in the cassava starch molecules might be the reason for the increasing trends of the shear stress and shear viscosity. The blends are classified as compatible blends because of the strong chemical bonding between different phases. SEM micrographs were used to clarify the compatibility. Power law behavior with pluglike flow profiles was observed for all sets of ENR–NR–cassava starch blends. Very low power law index values (<0.34) and highly pseudoplastic fluid behavior were also observed. The log additive rule was applied to plots of zero shear viscosity (consistency index) and the shear viscosity versus the concentration of ENR‐25. Positive deviation blending was observed, which indicates compatible blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1752–1762, 2004
Characterization of mechanical properties of γAl2O3 dispersed epoxy resin cured by γ‐ray radiation
Authors: Jin Kim Dong , Hyun Kang Phil , Chang Nho Young 
Published: December 2003

AbstractEpoxy resins are widely utilized as high performance thermosetting resins for many industrial applications, but they are characterized by relatively low toughness. Incorporation of rigid inorganics is suggested to improve the mechanical properties of epoxy resins. An attempt is made to disperse nanosized γ‐Al2O3 particles into diglycidyl ether of bisphenol A epoxy resins for the improvement of the mechanical properties. These hybrid epoxy–alumina composites are prepared using by the γ‐ray curing technique conducted at 100 kGy under nitrogen at room temperature. The composites are characterized by determining the gel content, flexural strength, Youngis modulus, and toughness at room temperature using scanning electron microscopy and FTIR studies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1898–1903, 2004
Treatment of Caribbean pine by in situ polymerization of styrene and furfuryl alcohol
Authors: Magalhães Washington Luiz Esteves , da Silva Renato Romano 
Published: December 2003

AbstractCaribbean pine impregnated by the full cell treatment schedule with styrene, furfuryl alcohol (FFA), and styrene–FFA monomers was cured for 48 h at 100°C. Styrene did not penetrate inside the wood cell wall; instead, it adhered on the cell wall surfaces and fill cell lumens. The volume contraction during the formation of polystyrene causes the volume contraction of the wood sample. The permanent volumetric swelling is attained only for samples treated with FFA, which is caused by cell wall impregnation. The dimensional stability of the treated wood samples is evaluated with the antiswell efficiency coefficient (ASE). The water repellency is expressed as the water‐repellent effectiveness (WRE). Treatment with styrene improves the water repellence, whereas a double treatment increases the dimensional stability. Lixiviation slightly affects the ASE and WRE coefficients. The treatments improve the Shore D hardness in comparison to untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1763–1769, 2004
Compatibilization of nitrile‐butadiene rubber/ethylene‐propylene‐diene monomer blends by mercapto‐modified ethylene‐vinyl acetate copolymers
Authors: Oliveira Marcia G. , Soares Bluma G. 
Published: December 2003

AbstractMercapto‐modified ethylene‐vinyl acetate (EVASH) has been employed as a reactive compatibilizing agent for nitrile‐butadiene rubber (NBR)/ethylene‐propylene‐diene monomer (EPDM) blends vulcanized with a sulfur/2,2′‐dithiobisbenzothiazole (MBTS) single accelerator system and a (sulfur/MBTS/tetramethylthiuram disulfide (TMTD) binary accelerator system. The addition of 5.0 phr EVASH resulted in a significant improvement in the tensile properties of blends vulcanized with the sulfur/MBTS system. In addition to better mechanical performance, these functionalized copolymers gave rise to a more homogeneous morphology and, in some cases, better aging resistance. The compatibilization was not efficient in blends vulcanized with the S/MBTS/TMTD binary system, probably because of the faster vulcanization process occurring in this system. The good performance of these EVASH samples as compatibilizing agents for NBR/EPDM blends is attributed to the higher polarity of these components that is associated with their lower viscosity. Dynamic mechanical analysis also suggested a good interaction between the phases in the presence of EVASH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1404–1412, 2004