bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyetheretherketone Films with Low Thermal Expansion for Flexible Printed Circuit Boards
Authors: Seidel C. , Muenstedt H. 
Published: February 2008

Abstract
Rigid and flexible circuit boards consist of layers of different materials. Particularly, the different thermal expansion coefficients of thermoplastic polymers and metals can lead to problems during application. The investigations presented are focused on the high-temperature thermoplastic polyetheretherketone (PEEK), as it has a remarkable potential for novel flexible circuit boards. The work shows the significant thermal expansion reductions that can be reached in a thermoplastic polyetheretherketone (PEEK) film by the incorporation of different contents of calcium carbonate or talc fillers and compares their effectiveness. Particularly the influence of filler geometry on the thermal expansion is studied in detail. The effect of the filling on mechanical properties and the dimensional stability of the PEEK films under thermal load is investigated quantitatively.
Hybrid Organic‐Inorganic Materials from Di‐(2‐pyridyl)methylamine‐Palladium Dichloride Complex as Recoverable Catalysts for Suzuki, Heck and Sonogashira Reactions
Authors: Trilla Montserrat , Pleixats Roser , Man Michel Wong Chi , Bied Catherine , Moreau Joël J. E. 
Published: February 2008

AbstractHybrid silica materials containing the di‐(2‐pyridyl)methylamine‐palladium dichloride complex, prepared by sol‐gel cogelification, are efficient recyclable catalysts for Suzuki (aryl bromides and chlorides), Heck (aryl bromides) and Sonogashira reactions (aryl iodides and bromides). Formation of palladium(0) nanoparticles is observed in the Suzuki and Heck reactions but not in the Sonogashira coupling.
Adenosine A2A receptor antagonists exert motor and neuroprotective effects by distinct cellular mechanisms
Authors: Yu Liqun , Shen Hai‐Ying , Coelho Joana E. , Araújo Inês M. , Huang Qing‐Yuan , Day Yuan‐Ji , Rebola Nelson , Canas Paula M. , Rapp Erica Kirsten , Ferrara Jarrod , Taylor Darcie , Müller Christa E. , Linden Joel , Cunha Rodrigo A. , Chen Jiang‐Fan 
Published: February 2008

AbstractObjectiveTo investigate whether the motor and neuroprotective effects of adenosine A2A receptor (A2AR) antagonists are mediated by distinct cell types in the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) model of Parkinson's disease.MethodsWe used the forebrain A2AR knock‐out mice coupled with flow cytometric analyses and intracerebroventricular injection to determine the contribution of A2ARs in forebrain neurons and glial cells to A2AR antagonist‐mediated motor and neuroprotective effects.ResultsThe selective deletion of A2ARs in forebrain neurons abolished the motor stimulant effects of the A2AR antagonist KW‐6002 but did not affect acute MPTP neurotoxicity. Intracerebroventricular administration of KW‐6002 into forebrain A2AR knock‐out mice reinstated protection against acute MPTP‐induced dopaminergic neurotoxicity and attenuated MPTP‐induced striatal microglial and astroglial activation.InterpretationA2AR activity in forebrain neurons is critical to the control of motor activity, whereas brain cells other than forebrain neurons (likely glial cells) are important components for protection against acute MPTP toxicity. Ann Neurol 2008
A new amyloid β variant favoring oligomerization in Alzheimer's‐type dementia
Authors: Tomiyama Takami , Nagata Tetsu , Shimada Hiroyuki , Teraoka Rie , Fukushima Akiko , Kanemitsu Hyoue , Takuma Hiroshi , Kuwano Ryozo , Imagawa Masaki , Ataka Suzuka , Wada Yasuhiro , Yoshioka Eito , Nishizaki Tomoyuki , Watanabe Yasuyoshi , Mori Hiroshi 
Published: February 2008

AbstractObjectiveSoluble oligomers of amyloid β (Aβ), rather than amyloid fibrils, have been proposed to initiate synaptic and cognitive dysfunction in Alzheimer's disease (AD). However, there is no direct evidence in humans that this mechanism can cause AD. Here, we report a novel amyloid precursor protein (APP) mutation that may provide evidence to address this question.MethodsA Japanese pedigree showing Alzheimer's‐type dementia was examined for mutations in APP, PSEN1, and PSEN2. In addition, 5,310 Japanese people, including 2,121 patients with AD, were screened for the novel APP mutation. The pathogenic effects of this mutation on Aβ production, degradation, aggregation, and synaptotoxicity were also investigated.ResultsWe identified a novel APP mutation (E693Δ) producing variant Aβ lacking gulutamate‐22 (E22Δ) in Japanese pedigrees showing Alzheimer's‐type dementia and AD. Although the secretion of total Aβ was markedly reduced by this mutation, the variant Aβ was more resistant to proteolytic degradation. The mutant peptides showed the unique aggregation property of enhanced oligomerization but no fibrillization, and inhibited hippocampal long‐term potentiation more potently than wild‐type peptide in rats in vivo. Consistent with the nonfibrillogenic property of the variant Aβ, a very low amyloid signal was observed in the patient's brain on positron emission tomography using Pittsburgh compound‐B.InterpretationThe E693Δ mutation has been suggested as a cause of dementia because of enhanced formation of synaptotoxic Aβ oligomers. Our findings may provide genetic validation in humans for the emerging hypothesis that the synaptic and cognitive impairment in AD is primarily caused by soluble Aβ oligomers. Ann Neurol 2008
Effect of phenserine treatment on brain functional activity and amyloid in Alzheimer's disease
Authors: Kadir Ahmadul , Andreasen Niels , Almkvist Ove , Wall Anders , Forsberg Anton , Engler Henry , Hagman Göran , Lärksäter Marie , Winblad Bengt , Zetterberg Henrik , Blennow Kaj , Långström Bengt , Nordberg Agneta 
Published: February 2008

AbstractObjectiveThe effects of (−)‐phenserine (phenserine) and placebo/donepezil treatment on regional cerebral metabolic rate for glucose (rCMRglc) and brain amyloid load were investigated by positron emission tomography in 20 patients with mild Alzheimer's disease in relation to cerebrospinal fluid (CSF) and plasma biomarkers, and cognitive function.MethodsThe first 3 months of the study was a randomized, double‐blind, placebo‐controlled phase, during which 10 patients received phenserine (30mg/day) and 10 patients the placebo. Three to 6 months was an open‐label extension phase, during which the placebo group received donepezil (5mg/day) and the phenserine group remained on phenserine. After 6 months, all patients received phenserine treatment up to 12 months. The patients underwent positron emission tomography examinations to measure rCMRglc (18F‐FDG) and amyloid load (11C‐PIB) at baseline and after 3 and 6 months of the treatment. Neuropsychological and biomarker data were collected at the three times of positron emission tomography imaging.ResultsStatistically significant effects on a composite neuropsychological test score were observed in the phenserine‐treated group compared with the placebo and donepezil group at 3 and 6 months, respectively. Values of rCMRglc were significantly increased in several cortical regions after 3 months of phenserine treatment, compared with baseline, and correlated positively with cognitive function and CSF β‐amyloid 40 (Aβ40). Cortical Pittsburgh Compound B retention correlated negatively with CSF Aβ40 levels and the ratio Aβ/β‐secretase–cleaved amyloid precursor protein. In CSF, Aβ40 correlated positively with the attention domain of cognition.InterpretationPhenserine treatment was associated with an improvement in cognition and an increase in rCMRglc. Ann Neurol 2008
Nanocrystallite regions of guar gum filled PU/PAN composites before and after biodegradation using WAXS
Authors: Kumar H. , Siddaramaiah  , Somashekar R. , Mahesh S. S. , Manjunath A. 
Published: February 2008

AbstractPolyurethane/polyacrylonitrile semi‐interpenetrating polymer network containing varying weight percent of guar gum were prepared. The resulting composites were subjected to biodegradation with the help of specific fungi Aspergillus niger. The composite before and after biodegradation were subjected to wide angle X‐ray scattering studies. The nanocrystallite regions, area, and size are determined from X‐ray data using three different asymmetric column length functions. A comparison of these parameters does explain the nature of biodegradation at microlevel. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of porous materials by 2‐nitroresorcinol/cyanuric chloride thermal polycondensation in emulsions
Authors: Audouin Fabrice , Birot Marc , Pasquinet Éric , Deleuze Hervé , Besnard Olivier , Poullain Didier 
Published: February 2008

AbstractRigid monoliths were prepared from concentrated oil in water (O/W) emulsions by a base‐catalyzed polycondensation reaction of 2‐nitroresorcinol with cyanuric chloride. Mercury intrusion/extrusion porosimetry confirmed that the obtained monoliths were porous with an open porosity. However, scanning electron microscopy showed that the structure of these materials was different from that of emulsion‐derived materials previously described in the literature [polymerized high internal phase emulsions (polyHIPEs)]. In comparison with polystyrene/divinylbenzene‐based polyHIPEs obtained by radical polymerization, these materials exhibited a higher skeletal density, and thermogravimetric analysis and differential scanning calorimetry analysis indicated that they were more thermally stable. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
In situ pH‐decrease‐induced gelation of sodium alginate/carboxymethylated konjac glucomannan
Authors: Gao Shanjun , Wu Chengdong , Nishinari Katsuyoshi 
Published: February 2008

AbstractThe gelation kinetics and rheological properties of a mixture system containing two anionic polysaccharides, sodium alginate and carboxymethylated konjac glucomannan, in the presence of glucono‐delta‐lactone were investigated with dynamic viscoelastic measurements. The slow release of protons induced by glucono‐delta‐lactone gave birth to partly uncharged polymer chains and partly shielded electrostatic repulsion, resulting in an interpolymer association. This segregative interaction brought about a significant improvement in the elastic modulus of the resultant gel. The strongest synergism occurred at a carboxymethylated konjac glucomannan concentration of 29.9 wt %, exhibiting the highest gel strength. Increasing the content or the degree of substitution of carboxymethylated konjac glucomannan resulted in slower gelation kinetics. The fractal dimension of the incipient gel, which was not greatly affected by the mixing ratio or the degree of substitution of carboxymethylated konjac glucomannan, reflected a rather compact gel structure network. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Conductivity and structure of a polyamide/silver iodide nanocomposite
Authors: Fujimori Yoshie , Gotoh Yasuo , Kawaguchi Akio , Ohkoshi Yutaka , Nagura Masanobu 
Published: February 2008

AbstractIn this study, the structure and properties of an organic–inorganic composite material prepared from nylon 6 doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of nylon 6 with polyiodide ions such as I and I by immersion in an iodine/potassium iodide (I2–KI) aqueous solution followed by reaction in a silver nitrate (AgNO3) aqueous solution; this resulted in the in situ formation of β‐AgI fine particles within the nylon 6 matrix. The AgI content formed in the composite was dependent on the immersion temperatures of the I2–KI and AgNO3 solutions. Lower solution temperatures resulted in larger amounts of AgI in the composite. This method readily provided a composite with a high content of AgI in nylon 6 and a conductivity of approximately 10−5 Ω−1 cm−1. In a uniaxially oriented nylon 6 matrix, AgI particles precipitated with anisotropic shape, which was caused by the orientation of the precursor polyiodide ions. The structure of the oriented composite provided the anisotropic conductivity. Additionally, the composite exhibited high antibacterial properties. The procedure used in this study is considered a unique method for the preparation of organic–inorganic composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Green and self‐lubricating polyoxymethylene composites filled with low‐density polyethylene and rice husk flour
Authors: Li Ke , Xiang Dinghan , Lei Xiaoyu 
Published: February 2008

AbstractPolyoxymethylene (POM) composites filled with low‐density polyethylene (LDPE) and rice husk flour (RHF) were prepared by injection molding. The POM/5 wt % LDPE/7.5 wt % RHF composite exhibited the lowest wear rate, whereas the coefficient of friction remained low, and the POM/5 wt % LDPE/5 wt % RHF composite had the best mechanical properties. X‐ray diffraction analysis was carried out, and the worn surfaces were examined with scanning electron microscopy. The results showed that the addition of the filler reduced the crystallinity degree of the POM composites. The main wear mechanism for unfilled POM was adhesion, whereas for the POM composites, wear seemed to occur mainly by fatigue and abrasion. It was experimentally confirmed that the POM composite filled with LDPE and RHF, which is well‐performing, low‐cost, and environmentally friendly, could be a potential material for tribological applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Morphology and barrier properties of nanobiocomposites of poly(3‐hydroxybutyrate) and layered silicates
Authors: Sanchez‐Garcia M. D. , Gimenez E. , Lagaron J. M. 
Published: February 2008

AbstractPolyhydroxybutyrate (PHB) is generally considered to be a very uneasy biopolymer to handle because of significant instability during melt processing and some excessive brittleness. This work studied the morphological, thermal, and barrier properties of novel melt‐mixed nanobiocomposites of PHB, poly(ε‐caprolactones) (PCL), and layered phyllosilicates based on commercial organomodified kaolinite and montmorillonite clay additives. The addition of PCL component to the blend was seen to reduce oxygen permeability but it was also found to lead to a finer dispersion of the clay. The addition of highly intergallery swollen organomodified montmorillonite clays to the PHB blend led to a highly dispersed morphology of the filler, but this simultaneously increased to a significant extend the melt instability of the biopolymer. Nevertheless, the organomodified kaolinite clay, despite the fact that it was found to both lead to less dispersed and irregular morphology, particularly for higher clay loadings, it led to enhanced barrier properties to oxygen, D‐limonene, and water. D‐limonene and specially water molecules were, however, found to sorb in both hydrophobic and hydrophilic sites of the filler, respectively, hence diminishing the positive barrier effect of an enlarged tortuosity factor in the permeability. Mass transport properties were found to depend on the type of penetrant and modeling of the permeability data to most commonly applied formalisms was not found to be satisfactory because of factors such as morphological alterations, heterogeneity in the clay dispersion, and penetrant solubility in the filler. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tribological testing of peroxide cured HNBR with different MWCNT and silica contents under dry sliding and rolling conditions against steel
Authors: Felhös D. , Karger‐Kocsis J. , Xu D. 
Published: February 2008

AbstractThe sliding, and rolling friction and wear behaviors of peroxide cured hydrogenated nitrile rubber (HNBR) with 10 and 30 parts per hundred rubber (phr) multiwall carbon nanotube (MWCNT) and silica, respectively, were investigated. Mechanical properties (hardness, tensile modulus, ultimate tensile strength and strain, tear strength) of the rubbers were determined. Dynamic‐mechanical thermal analysis was also performed and the apparent crosslink density estimated. Tribological properties were investigated in pin (steel)‐on‐plate (rubber), with roller (steel)‐on‐plate (rubber), with oscillating steel cylinder on rubber plate (Fretting) and with rolling ball (steel)‐on‐plate (rubber) (RBOP) test configurations. Coefficient of friction and specific wear rate (Ws) of the HNBR systems were determined. It was established that the resistance to wear increases with increasing filler content, and the incorporation of MWCNT was more advantageous than silica from the viewpoint of dry sliding and rolling performance. The friction and wear characteristics strongly depended on the test configurations. The worn surface of the HNBR systems was inspected in scanning electron microscope to conclude the typical wear mechanisms which were discussed accordingly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and electrorheological activity of a modified kaolinite/carboxymethyl starch hybrid nanocomposite
Authors: Zhao Xiaopeng , Wang Baoxiang , Li Jia 
Published: February 2008

AbstractAccording to physical and chemical designs, a novel modified kaolinite/carboxymethyl starch (CMS) nanocomposite was synthesized with a displacement method with dimethyl sulfoxide modified kaolinite as an intermediate. The material characterizations were carried out by X‐ray diffraction, transmission electron microscopy, thermogravimetric analysis, and scanning electron microscopy. The analyses showed that kaolinite was dispersed at the nanometer‐scale segments into the CMS matrix. The electrorheological behavior of the modified kaolinite/CMS hybrid nanocomposite dispersed in silicone oil was investigated. Under electric field strength (E) = 4 kV/mm and shear rate , the shear stress of the modified kaolinite/CMS nanocomposite electrorheological fluid could be up to 8380 Pa, which was 10.4 times that of the electrorheological fluid at zero field. The modified kaolinite/CMS nanocomposite electrorheological fluid also exhibited good sedimentation properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of different functionalized multiwall carbon nanotubes on the mechanical properties of poly(ethylene terephthalate) fibers
Authors: Shen Liming , Gao Xushan , Tong Yan , Yeh Andrew , Li Ruixia , Wu Dacheng 
Published: February 2008

AbstractMaster batches with four different kinds of functionalized multiwall carbon nanotubes (MWCTs) were prepared through the mixing of MWCTs with poly(ethylene terephthalate) (PET) (0.01 : 0.99 w/w) in trifluoroacetic acid/dichloromethane mixed solvents (0.7 : 0.3 v/v) followed by the removal of the solvents in the mixture by flocculation. The results of scanning electron microscopy showed that a good dispersion of MWCTs in PET was achieved. The reinforced fibers were fabricated by the melt spinning of PET chips with small amounts of the master batch and then further postdrawing. The optimal spinning conditions for the reinforcement of fibers were a 0.6‐mm spinneret hole and a 250 m/min wind‐up speed. Among the four master batches, the fibers obtained from PET/master batch B made by acid‐treatment had the highest enhancement of mechanical properties. For a 0.02 wt % loading of acid‐treated MWCT, the breaking strength of the PET/master batch B composite fibers increased by 36.9% (from 4.45 to 6.09 cN/dtex), and the initial modulus increased by 41.2% (from 80.7 to 113.9 cN/dtex). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Prediction of lateral lymph node metastases in medullary thyroid cancer
Authors: Machens A , Hauptmann S , Dralle H 
Published: February 2008

Abstract

Background
In medullary thyroid cancer (MTC), there is a concordance between central and lateral neck involvement, but this relationship has not been assessed quantitatively.

Methods
After compartment-oriented lymphadenectomy for untreated MTC, the numbers of central lymph node metastases with ipsilateral (195 patients) and contralateral (185 of 195 patients) lateral lymph node metastases were analysed retrospectively.

Results
With one to three positive central lymph nodes, involvement of the ipsilateral lateral neck increased from 10·1 per cent (with no central node involvement) to 77 per cent, and from a mean of 0·6 to 3·7 nodal metastases (P &lt; 0·001). With four or more central nodes, the rate was 98 per cent, with 10·7 nodal metastases (P = 0·001). A weaker increase was observed in the contralateral lateral neck: with one to nine positive central nodes, contralateral lateral neck involvement increased from 4·9 to 38 per cent, and from a mean of 0·6 to 2·3 nodal metastases (P = 0·011). With ten or more positive central nodes, the rate rose to 77 per cent, with 6·2 nodal metastases (P = 0·009). With one exception, contralateral lateral nodal metastases coexisted with metastases in the central and ipsilateral lateral neck.

Conclusion
These data may lay the groundwork for more informed decision-making regarding dissection of the lateral neck compartments.
Prognostic significance of extracapsular lymph node involvement in patients with adenocarcinoma of the ampulla of Vater
Authors: van der Gaag N A , ten Kate F J W , Lagarde S M , Busch O R C , van Gulik T M , Gouma D J 
Published: February 2008

Abstract

Background
Lymphatic dissemination is an important predictor of survival in patients with adenocarcinoma of the ampulla of Vater. The incidence and clinical consequences of extracapsular lymph node involvement (LNI) in patients who undergo resection are unknown.

Methods
In a consecutive series of 160 patients with adenocarcinoma of the ampulla of Vater, 75 (46·9 per cent) had positive lymph nodes (N1). The relation of extracapsular LNI with tumour stage and number of positive nodes was evaluated and its prognostic significance analysed.

Results
Extracapsular LNI was identified in 44 (59 per cent) of the 75 patients. Median overall survival was 30 and 18 months in patients with intracapsular and extracapsular LNI respectively (P = 0·015). The 5-year overall survival rate was 20 and 9 per cent respectively, compared with 59 per cent in patients without LNI (N0). Extracapsular LNI and tumour differentiation were independent prognostic factors for survival. In patients with N1 disease, extracapsular LNI was the only significant prognostic factor for recurrent disease after radical resection (R0).

Conclusion
The presence of extracapsular LNI identifies a subgroup of patients who have a significantly worse prognosis. Adjuvant therapy is advised following resection in these patients.
Augmented reality agents for user interface adaptation
Authors: Barakonyi István , Schmalstieg Dieter 
Published: February 2008

AbstractMost augmented reality (AR) applications are primarily concerned with letting a user browse a 3D virtual world registered with the real world. More advanced AR interfaces let the user interact with the mixed environment, but the virtual part is typically rather finite and deterministic. In contrast, autonomous behavior is often desirable in ubiquitous computing (Ubicomp), which requires the computers embedded into the environment to adapt to context and situation without explicit user intervention. We present an AR framework that is enhanced by typical Ubicomp features by dynamically and proactively exploiting previously unknown applications and hardware devices, and adapting the appearance of the user interface to persistently stored and accumulated user preferences. Our framework explores proactive computing, multi‐user interface adaptation, and user interface migration. We employ mobile and autonomous agents embodied by real and virtual objects as an interface and interaction metaphor, where agent bodies are able to opportunistically migrate between multiple AR applications and computing platforms to best match the needs of the current application context. We present two pilot applications to illustrate design concepts. Copyright © 2007 John Wiley & Sons, Ltd.