bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composition and Morphology Control in Ordered Mesostructured High‐Temperature Ceramics from Block Copolymer Mesophases
Authors: Kamperman Marleen , Du Phong , Scarlat Raluca O. , Herz Erik , Werner‐Zwanziger Ulrike , Graf Robert , Zwanziger Josef W. , Spiess Hans W. , Wiesner Ulrich 
Published: August 2007

AbstractThe co‐assembly between a polyisoprene‐block‐poly(dimethylaminoethyl methacrylate) block copolymer and poly(ureamethylvinyl)silazane is investigated. The hybrid morphology can be controlled by systematically increasing the inorganic‐to‐organic ratio or by changing the molecular weight of the block copolymer. Temperature treatment up to 1 500 °C of the hybrids resulted in mesoporous, ordered non‐oxide‐type ceramics. The results suggest that careful control of co‐assembly processes enables access to nanostructured high‐temperature ceramics that may have novel mechanical, thermal, and chemical properties.magnified image
Probing Proton Mobility in Polyvinazene and its Sulfonated Derivatives Using 1H Solid‐State NMR
Authors: Ye Gang , Fortier‐McGill Blythe , Traer Jason W. , Czardybon Agata , Goward Gillian R. 
Published: August 2007

AbstractThe proton dynamics of PV and its sulfonated derivatives have been studied using high‐resolution solid state 1H MAS NMR. Variable temperature experiments were used to determine the activation energy for transportation of hydrogen bonded protons, found to be 22 ± 1 kJ · mol−1 for PV and 13 ± 1 kJ · mol−1 for PV–B25. The proton exchange between sulfonic acid group and vinazene ring observed from both variable temperature experiments and 1H EXSY NMR experiments provides a good explanation for this difference. A rotor‐synchronized homonuclear double quantum filter sequence was used to distinguish protons of differing mobilities. A model is proposed to understand the distinct proton mobilities in these materials.magnified image
Comparison Between Coarse‐Graining Models for Polymer Systems: Two Mapping Schemes for Polystyrene
Authors: Harmandaris Vagelis A. , Reith Dirk , van der Vegt Nico F. A. , Kremer Kurt 
Published: August 2007

AbstractWe present a detailed study of a new, optimized coarse‐grained (CG) model of polystyrene (PS) and compare it with a recently published one (Harmandaris et al.,Macromolecules2006,39, 6708). By implementing a different mapping scheme, the new model, augmented with softer nonbonded interactions, better reproduces the local chain conformations and melt packing observed in atomistic simulations of atactic PS. Both models properly predict the bonded distributions and are capable of simulating different tacticities without needing sidegroups. Both CG models fit dynamic data from long atomistic simulations after determining the scale factor for the simulation time. Together with a rigorous back‐mapping procedure from the mesoscopic to atomistic description, this opens up a very feasible way for generating very long atomistic trajectories.magnified image
Director Orientation of Nematic Side‐Chain Liquid Crystalline Polymers Under Shear Flow: Comparison of a Flow‐Aligning and a Non‐Flow‐Aligning Polysiloxane
Authors: Siebert Hartmut , Quijada‐Garrido Isabel , Vermant Jan , Noirez Laurence , Burghardt Wesley R. , Schmidt Claudia 
Published: August 2007

AbstractThe flow behavior and phase structure of two side‐chain liquid‐crystalline polysiloxanes with the same mesogens but different spacers of either four (PSi4) or six (PSi6) methylene groups are studied in the nematic phase by2H NMR, polarization microscopy, and scattering of light, neutrons, and X‐rays. PSi4 is flow‐aligning, forming a monodomain with the director close to the flow direction, whereas PSi6 is non‐flow‐aligning showing a polydomain structure with a preferred director orientation corresponding to the log‐rolling state. The flow behavior of PSi6 is related to the presence of strong smectic clusters. The director tilt in the smectic clusters of both polymers is reported.magnified image
Rheological Properties of Concentrated Solutions of Aliphatic Hyperbranched Polyesters
Authors: Vuković Jasna , Lechner Manfred D. , Jovanović Slobodan 
Published: August 2007

AbstractThe rheological investigation of concentrated solutions of aliphatic hyperbranched polyesters (AHBP) in N‐methyl‐2‐pyrrolidinon (NMP) is presented. Two series of hydroxy‐functional AHBP were synthesized using pseudo‐one‐step and one‐step procedure. Three commercial (Boltorn®) AHBP were also investigated. In the examined temperature region (10–50 °C), AHBP solutions (c ≤ 45 wt.‐%) exhibited Newtonian behavior. The same was observed for 50 and 55 wt.‐% solutions at T ≥ 40 °C. However, at T < 50 °C, solutions of AHBP of higher concentrations (50 and 55 wt.‐%) showed shear thinning behavior. Values of the flow activation energies were calculated for all examined AHBP. The influence of the procedure for the synthesis, concentration and temperature on rheological behavior of AHBP solutions in NMP is discussed.magnified image
Enhanced, Perpendicular Liquid‐Crystal Alignment on Rubbed Films of a Coumarin‐Containing Polystyrene
Authors: Kang Hyo , Kwon Ki‐Sun , Kang Daeseung , Lee Jong‐Chan 
Published: August 2007

AbstractWe synthesized a series of polystyrene derivatives containing coumarin side groups using polymer analogous reactions. The liquid‐crystal (LC) alignment director for these polymer films was found to be perpendicular to the rubbing direction. The contrast ratio and anchoring‐energy values of these polystyrene derivatives were found to be much greater than those of polystyrene and poly(chloromethylstyrene), indicating that the coumarin side groups increase the aligning ability. For example, the anchoring energy of a polymer with 82 mol‐% of coumarin‐containing monomeric units, compared to polystyrene, is about 7 × 10−5 J · m−2 and 1 × 10−7 J · m−2, respectively.magnified image
Mechanical Properties of Hemp‐Fibre‐Reinforced Euphorbia Composites
Authors: Mwaikambo Leonard Y. , Tucker Nick , Clark Andrew J. 
Published: August 2007

AbstractA composite material consisting of hydroxide‐modified hemp fibres and euphorbia resin was produced. The composites were tested in tension, short‐beam interlaminar shear stress and in impact. There was an increase in the tensile strength and modulus for resins with high‐hydroxyl‐group based composites. Similar results were obtained for interlaminar shear stress while low‐hydroxyl group euphorbia resin based composites exhibited high impact strength. The euphorbia resin with high hydroxyl content yielded composites with high stiffness. The use of euphorbia‐based resins in composite manufacture increases the value of the euphorbia oil as well as creating a new route of composite manufacturing.magnified image
Use of SEBS/EPR and SBR/EPR as Binary Compatibilizers for PE/PP/PS/HIPS Blends: A Work Oriented to the Recycling of Thermoplastic Wastes
Authors: Equiza Nilton , Yave Wilfredo , Quijada Raúl , Yazdani‐Pedram Mehrdad 
Published: August 2007

AbstractRecycling of thermoplastic wastes consisting of PE/PP/PS/HIPS blends was investigated by using SEBS/EPR and SBR/EPR as compatibilizers. The effect of the binary compatibilizer systems and processing conditions on the mechanical properties and morphology of the blends are discussed. The SEBS/EPR system allowed blends with better mechanical properties to be obtained than the SBR/EPR system; this was attributed to the chemical structure similarity between compatibilizers and recycled materials. The optimal conditions for processing of the recycled thermoplastics (blends) were found to be 190 °C, 14 min of processing time and 3.5 wt.‐% of compatibilizer. The morphology and mechanical properties of the blends were discussed using theoretical phase diagrams and models proposed in the literature, and good agreements between these properties were found.magnified image
EVA Nanocomposites Elaborated with Bentonite Organo‐Modified by Wet and Semi‐Wet Methods
Authors: Cárdenas Miguel Angel , García‐López David , Fernández José Francisco , Gobernado‐Mitre Isabel , Merino Juan Carlos , Pastor José María , Martínez Juan de Dios , Barbeta Javier , Calveras Daniel 
Published: August 2007

AbstractEVA copolymer/organoclay nanocomposites were prepared using melt‐compounding. Organoclays were obtained using wet and semi‐wet modification methods. These methods enable us to obtain organoclays with adequate modifier incorporation, but organoclays with a homogeneous and narrow agglomeration size distribution were obtained only with the wet method. TS and EB were higher for nanocomposites obtained with organoclays prepared using the wet method. Analysis of Limiting Oxygen Index, UL94 test and Cone Calorimeter test showed that the retardant properties of nanocomposites were also influenced by the kind of modifiers and the modification method.magnified image
The Influence of Interchain Branches on Solid State Packing, Hole Mobility and Photovoltaic Properties of Poly(3‐hexylthiophene) (P3HT)
Authors: Tu Guoli , Bilge Askin , Adamczyk Sylwia , Forster Michael , Heiderhoff Ralf , Balk Ludwig Josef , Mühlbacher David , Morana Mauro , Koppe Markus , Scharber Markus C. , Choulis Stelios A. , Brabec Christoph J. , Scherf Ullrich 
Published: August 2007

AbstractThe hole mobility and power conversion efficiency of bulk heterojunction solar cells based on P3HT‐type donor polymers and the soluble fullerene derivative [6,6]‐phenyl C61 butyric acid methyl ester (PCBM) as an acceptor both show a strong sensitivity to the introduction of interchain branches into the P3HT backbones. Branched B‐P3HT copolymers display a distinctly decreased hole mobility and reduced solar cell power conversion efficiency with increasing amount of interchain 3.3′‐bithiophene branches within the polythiophene macromolecules. The results illustrate the primary importance of proper solid state packing towards optimum charge transport and solar cell performance.magnified image
Anionic Polymerization of Methyl Methacrylate with the Aid of Lithium Trimethylsilanolate (Me3SiOLi) ‐ Superior Control of Isotacticity and Molecular Weight
Authors: Kitaura Takehiro , Kitayama Tatsuki 
Published: August 2007

AbstractHighly isotactic‐specific polymerization of methyl methacrylate (MMA) was developed by using a combined anionic initiator comprising α‐lithioisobutyrate (Li‐iPrIB) and a large excess of lithium trimethylsilanolate (Me3SiOLi), which afford, in particular, isotactic poly(methyl methacrylate) (PMMA) with isotactic triad content of up to 99.5% under the adjusted polymerization conditions. The polymerization system also exhibited a high activity such that isotactic PMMA with $\overline M _{\rm n}$ of over 800 000 and narrow molecular weight distribution ($\overline M _{\rm w} /\overline M _{\rm n}$ < 1.2) was obtained.magnified image
Poly(2,7‐carbazole) Derivatives as Semiconductors for Organic Thin‐Film Transistors
Authors: Wakim Salem , Blouin Nicolas , Gingras Emilie , Tao Ye , Leclerc Mario 
Published: August 2007

AbstractNew poly(2,7‐carbazole) derivatives have been synthesized using Yamamoto or Stille coupling reaction. These polymers are highly soluble in common organic solvents and have relatively high molecular weights. Solution‐processed organic field‐effect transistors using these new polymeric semiconductors were found to exhibit a hole mobility up to 2.0 × 10−3 cm2·V−1s−1 with a current on/off ratio of 5 × 104 under ambient conditions.magnified image
Easy One‐Pot Synthesis of a Reactive Hydrogel from Commercially Available 2‐Isocyanatoethyl Methacrylate and K2S2O5
Authors: Barruet Julien , Gaillet Christine , Penelle Jacques 
Published: August 2007

AbstractAddition of commercially available 2‐isocyanatoethyl methacrylate to a water solution of potassium bisulfite unexpectedly yields an anionically charged hydrogel. Structural analysis shows the presence of sulfonato‐blocked isocyanates (with no detectable residual isocyanates), a full polymerization of the vinyl groups, and the appearance of urea functional groups. A mechanism is proposed to explain the gel formation, based on a combination of bisulfite‐initiated free‐radical polymerization, crosslinking by urea bridge formation, and addition of bisulfite ions to isocyanate groups. Some basic physical properties (TGA, swelling) of the gel are presented.magnified image
Freezing of gait affects quality of life of peoples with Parkinson's disease beyond its relationships with mobility and gait
Authors: Moore Orna , Peretz Chava , Giladi Nir 
Published: August 2007

AbstractThe aim of this study was to examine the association between freezing of gait (FOG) and quality of life (QoL) in patients with Parkinson's disease (PD). PD patients (n = 118) completed the PDQ‐39 (QoL) and FOG‐Q questionnaires. Disease severity was assessed by the Hoehn and Yahr (H&Y) staging and the Unified Parkinson's Disease Rating Scale (UPDRS). The relations between those parameters were assessed using regression models. 66 men and 52 women (mean age 65.8 ± 10.2 years, UPDRS total score 48.4 ± 17.1, disease duration 8.5 ± 5.8 years, H&Y stage 2.7 ± 0.8) participated. FOG severity had a significant effect on QoL (P < 0.0015), accounting for disease severity assessed by UPDRS. Specifically, FOG severity was correlated with all the dimensions of the PDQ‐39 except for stigma and social support, as follows: with mobility, bodily discomfort, activity of daily living (ADL) (P < 0.005 in all), with emotional, communication, and cognition (P < 0.05 in all). FOG severity (FOG‐Q) was also found to affect a modified PDQ total score, without the mobility aspect (P = 0.0081). FOG should be viewed as a highly important symptom with regard to QoL of PD patients beyond its effect on gait and mobility. On the basis of the present results, special attention should be given to FOG in the treatment of patients with PD. © 2007 Movement Disorder Society
Patients with adult‐onset dystonic tremor resembling parkinsonian tremor have scans without evidence of dopaminergic deficit (SWEDDs)
Authors: Schneider Susanne A. , Edwards Mark J. , Mir Pablo , Cordivari Carla , Hooker Juzar , Dickson John , Quinn Niall , Bhatia Kailash P. 
Published: August 2007

AbstractWe present the clinical details and dopamine transporter SPECT scan results of 10 patients with arm tremor, including a rest component and reduced arm swing on the affected side, in whom the possibility of PD had been raised. All patients had signs of dystonia or components of their arm tremor that were compatible with dystonic tremor, and none had true akinesia with fatiguing or decrement, even after a mean follow‐up period of 5.8 years. All patients had normal dopamine transporter SPECT scans. Clinicians should be aware that primary adult‐onset dystonia can present with an asymmetric resting arm tremor, with impaired arm swing and sometimes also facial hypomimia or a jaw tremor, but without evidence of true akinesia. Given the important consequences of misdiagnosing such patients as PD, in cases with diagnostic uncertainty functional imaging should be considered. Among patients suspected of PD, dystonic tremor may be one cause of SWEDDs (Scans Without Evidence of Dopaminergic Deficit). © 2007 Movement Disorder Society
A large Italian family with Gilles de la Tourette syndrome: Clinical study and analysis of the SLITRK1 gene
Authors: Fabbrini Giovanni , Pasquini Massimo , Aurilia Cinzia , Berardelli Isabella , Breedveld Guido , Oostra Ben A. , Bonifati Vincenzo , Berardelli Alfredo 
Published: August 2007

AbstractOur objective was to report the clinical characteristics and to investigate the role of SLITRK1 gene in a large Italian family with Tourette syndrome (TS). The diagnosis of TS and chronic motor tics (CMT) was made according to “The Tourette Syndrome Classification Study Group” (1993). Psychiatric diagnoses were made by administering the Structured Clinical Interview for DSM and the Yale‐Brown Obsessive Compulsive Scale. Genetic study included direct sequencing and copy number analysis of the SLITRK1 gene, and haplotype analysis. We found tics or other behavioral manifestations in 15 subjects. Of these, 5 received a diagnosis of definite TS, 5 were classified as having definite CMT, 2 had definite nonspecific tic disorder, and 3 patients had obsessive–compulsive disorder without motor or phonic tics. Tics mainly involved the craniocervical district. Many patients with tics had coexisting psychiatric disorders, especially obsessive–compulsive disorder, performed poorly at school and had social problems. Direct sequencing and copy number analysis of the SLITRK1 gene, and haplotype analysis suggested that the SLITRK1 locus was not involved in this family. In conclusion, the distinctive clinical features in this family are the motor tics mainly involving the face and the neck and the severe coexisting psychiatric disorders. The negative results of the SLITRK1 analysis point to genetic heterogeneity in TS. © 2007 Movement Disorder Society
Genetic analysis of SCA 2 and 3 repeat expansions in essential tremor and atypical Parkinsonism
Authors: Tan Eng‐King , Tong Justina , Pavanni Ratnagopal , Wong Meng‐Cheong , Zhao Yi 
Published: August 2007

AbstractAnecdotal reports suggest that patients with spinocerebellar ataxia (SCA 2) patients can present with postural tremor with ataxia. We determined the prevalence of SCA2 and SCA3 mutations in a cohort of ET and atypical Parkinsonism patients. A total of 277 subjects comprising of 177 ET and 100 atypical Parkinsonism were examined. We identified one positive case of SCA3 among those who were diagnosed with ET, yielding a prevalence of 0.5%, but a zero prevalence among our atypical Parkinsonism patients. No study subjects carried an abnormal SCA2 repeat expansion. Our study highlights that SCA3 can present initially with ET symptoms, expanding the spectrum of genetic diseases that can be associated with ET‐like phenotype. Routine screening for SCA2 and SCA3 in ET and atypical Parkinsonism patients may not be cost effective. However, in the long‐term follow‐up of patients who present with an ET phenotype, clinicians should be vigilant for other neurological signs, which may be point to an alternate diagnosis. © 2007 Movement Disorder Society
Acute ataxia, Graves' disease, and stiff person syndrome
Authors: Chia Su‐Ynn , Chua Richard , Lo Yew‐Long , Wong Meng‐Cheong , Chan Ling‐Ling , Tan Eng‐King 
Published: August 2007

AbstractStiff person syndrome (SPS) has been associated with autoimmune diseases, such as Type 1 diabetes mellitus and autoimmune thyroid disease (Hashimoto's thyroiditis), among others. The association of SPS with hyperthyroidism is extremely rare. We describe a patient with uncontrolled Graves' disease and undiagnosed SPS, who presented initially with acute ataxia simulating a cerebrovascular accident. Initiation of immunosuppressive therapy dramatically improved the patient's Graves' disease within 2 weeks but the neurological symptoms were not alleviated after a follow‐up period of 3 years. © 2007 Movement Disorder Society
Coffee and tea consumption and the risk of Parkinson's disease
Authors: Hu Gang , Bidel Siamak , Jousilahti Pekka , Antikainen Riitta , Tuomilehto Jaakko 
Published: August 2007

AbstractSeveral prospective studies have assessed the association between coffee consumption and Parkinson's disease (PD) risk, but the results are inconsistent. We examined the association of coffee and tea consumption with the risk of incident PD among 29,335 Finnish subjects aged 25 to 74 years without a history of PD at baseline. During a mean follow‐up of 12.9 years, 102 men and 98 women developed an incident PD. The multivariate‐adjusted (age, body mass index, systolic blood pressure, total cholesterol, education, leisure‐time physical activity, smoking, alcohol and tea consumption, and history of diabetes) hazard ratios (HRs) of PD associated with the amount of coffee consumed daily (0, 1–4, and ≥5 cups) were 1.00, 0.55, and 0.41 (Pfor trend = 0.063) in men, 1.00, 0.50, and 0.39 (Pfor trend = 0.073) in women, and 1.00, 0.53, and 0.40 (Pfor trend = 0.005) in men and women combined (adjusted also for sex), respectively. In both sexes combined, the multivariate‐adjusted HRs of PD for subjects drinking ≥3 cups of tea daily compared with tea nondrinkers was 0.41 (95% CI 0.20–0.83). These results suggest that coffee drinking is associated with a lower risk of PD. More tea drinking is associated with a lower risk of PD. © 2007 Movement Disorder Society
Psychogenic camptocormia
Authors: Skidmore Frank , Anderson Karen , Fram David , Weiner William 
Published: August 2007

AbstractCamptocormia describes a severe forward‐flexion at the waist. Originally used in reference to a conversion disorder seen in military personel (Souques and Rosanoff‐Saloff, Rev Neurol 1915, 22, 937; Rosen and Frymoyer, Spine 1985, 10, 325; Miller and Forbes, Br J Psychiatry 1990, 157, 765; Perez‐Sales, Arch Phys Med Rehabil 1990, 71, 1078; Sinel and Eisenberg, Rev Rhum Mal Osteoartic 1992, 59, 169; Miller and Forbes, Mil Med 1990, 155, 561; Belgrano and Giordano, Rev Neurol 1947, 79, 25–35), the term has been adapted to describe severely flexed postures observed in Parkinson disease (Djaldetti et al., Mov Disord 1999, 14, 443), other basal ganglia disorders (Nieves et al., Mov Disord 2001, 16, 177; Reichel et al., Nervenarzt 2001, 72, 281), and muscular disease (Delcey et al., Rev Med Intern 2002, 23, 144; Van Gerpen, Mov Disord 2001, 16, 358). Although rare, psychogenic camptocormia is seen in civilian populations, presenting diagnostic challenges. We describe a patient whose initial history and examination suggested a psychogenic etiology for his camptocormic posture. A multidisciplinary approach elucidated the patient's motivations and emotional state, and has been helpful in management of this patient. © 2007 Movement Disorder Society
Immunolocalization of the High‐Mobility Group N2 protein and acetylated histone H3K14 in early developing parthenogenetic bovine embryos derived from oocytes of high and low developmental competence
Authors: Bastos Guilherme M. , Gonçalves Paulo Bayard D. , Bordignon Vilceu 
Published: August 2007

AbstractThis study investigated differences in the distribution of acetylated histone H3 at Lysine 14 (H3K14ac) and the High‐Mobility Group N2 (HMGN2) protein in the chromatin of early‐ (before 24 hr) and late‐cleaved (after 24 hr) bovine embryos derived from small‐ (1–2 mm) and large‐follicles (4–8 mm). The presence of HMGN2 and H3K14ac has been associated with different nuclear functions including chromatin condensation, transcription, DNA replication and repair. In vitro matured oocytes were parthenogenetically activated (PA) and cultured in synthetic oviduct fluid medium. Early‐ and late‐cleaved embryos were fixed at 36, 50, 60, 70 and 80 hr after PA to detect the presence of H3K14ac and HMGN2. The rates of nuclear maturation (81.1% vs. 58.7%), early cleavage (46.9% vs. 38.9%), and development to blastocyst stage (34.3% vs. 18.9%) were higher (P < 0.05) in oocytes derived from large‐ compared to small follicles. The proportion of positively stained nuclei at 50 and 60 hr after PA was higher for both H3K14ac (27.2% vs. 4.8% and 64.3% vs. 30%) and HMGN2 (47% vs. 21.3% and 60.6% vs. 46%) in early versus late cleaved embryos derived from small‐ versus large‐follicles, respectively. However, the rate of positive nuclei in early‐cleaved embryos from small‐versus large‐follicles was similar for HMGN2 (87% vs. 93%) but lower for H3K14ac (51% vs. 64.4%) at 80 hr after PA. These data suggest that less developmentally competent embryos derived from small follicles had an altered chromatin remodeling process at the early stages of development compared to those derived from large follicles that are more competent to support development to blastocyst stage. Mol. Reprod. Dev. 75: 282–290, 2008. © 2007 Wiley‐Liss, Inc.