bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Mechanical and Dielectric Relaxation Behavior of Chitosan Films: Influence of Water Content
Authors: González‐Campos J. Betzabe , Prokhorov Evgen , Luna‐Bárcenas Gabriel , Sanchez Isaac C. , Kovalenko Yuriy 
Published: September 2009

AbstractThe dynamic mechanical dielectric behavior of neutralized chitosan films has been investigated as a function of water content and temperature. Chitosan films exhibit three relaxation processes in the low frequency range: the first one between 86–102 °C, it corresponds to the α‐relaxation process and shifts to higher temperatures with decreasing water content; a second relaxation was observed from 80 °C to the onset of thermal degradation (240 °C) and it is identified as the σ‐relaxation often associated with proton mobility; and a third relaxation process in the 240–300 °C temperature range that corresponds to chitosan thermal degradation.
Ionic Conductivity of Polymer Electrolytes
Authors: Cardoso Judith , Vázquez Gerardo , Soria‐Arteche Olivia , Cruz Raúl , González Ignacio 
Published: September 2009

AbstractIn this work, the effect of different salts: LiCF3SO3 (lithium triflate, LiOTf) and LiCl in 1:1 mole ratio in a methacrylate‐type polymer with zwitterionic pendant groups (PMBS‐4) used as host polymer, are evaluated. By means of X‐ray diffraction patterns, the formation of a homogeneous solution is observed in the case of PMBS‐4/LiCl and PMBS‐4/LiOTf. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) allows determination of glass transition temperatures (Tg) and thermal stability of the polymers. Tg values of the two polymer electrolytes are 293 ± 2 K against PMBS‐4 which is 291 K. The initial decomposition temperatures (IDT) for PMBS‐4 and PMBS‐4/Lithium salt are 483 K and 460 K, respectively. The ac ionic conductivity (σ) was obtained using the electrochemical impedance spectroscopy (EIS). It was found that σ increases as temperature rises following a simple Arrhenius behavior and reaches a value of ∼6 × 10−4 S/cm in the case of PMBS‐4/LiCl and ∼2 × 10−2 S/cm in the case of PMBS‐4/LiOTf, both measured at 343 K.
Effect of Di(2‐ethyl hexyl phthalate)/Epoxidized Soybean Oil and Calcium Stearate/Zinc Stearate Ratios on the Tensile Properties of Plasticized PVC Formulations. A Study for Calcium Stearate Rich Formulations
Authors: González‐Ortiz Luis J. , Arellano Martín , Sánchez‐Peña M. Judith 
Published: September 2009

AbstractTwo series of plasticized PVC formulations were prepared, containing one of the following di (2‐ethyl hexyl phthalate)/epoxidized soybean oil ratios (phr/phr): (a) 35/3, (b) 55/3, (c) 45/0 or, (d) 45/6. For each ratio, the following calcium stearate/zinc stearate ratios (phr/phr) were considered: (a) 0.6/0.4, (b) 0.8/0.2 or, (c) 1.0/0.0; all formulations were prepared with a total content of stearate(s) of 1.0 phr. The difference between the series was the preheating of stearates (150 °C, 90 min), carried out before the dry‐blend preparation. The changes of tensile properties produced by the degradation process were measured in ribbons obtained by extrusion.
Tensile Properties of Self‐Crosslinkable Poly(n‐butyl methacrylate‐co‐N‐methylolacrylamide) Films Prepared by Emulsion and Microemulsion Latexes
Authors: Aguilar Jacobo , Rabelero Martín , Mendizábal Eduardo , Nuño‐Donlucas Sergio M. , Arellano Martín , Puig Jorge E. 
Published: September 2009

AbstractThe gel content, swelling degree and mechanical properties of self‐crosslinkable poly(n‐butyl methacrylate‐co‐N‐methylolacrylamide) films made by two‐stage emulsion (using sodium dodecyl sulfate as surfactant) or microemulsion (using cetyltrimethylammonium bromide as surfactant) polymerization processes in the presence of variable amounts of the chain transfer agent, n‐butyl mercaptan, are reported here. Latexes made by microemulsion polymerization contain much smaller nanoparticles with lower amount of gel than those obtained by the emulsion process. Stress‐strain tests in uncured and cured films indicate that microemulsion‐made films are tougher and exhibit smaller deformations at break.
Phase Behavior and Particle Formation of Poly (1H,1H‐dihydrofluorooctyl Methacrylate) in Supercritical CO2
Authors: Santoyo‐Arreola José G. , Vásquez‐Medrano Rubén C. , Ruiz‐Treviño Alberto , Luna‐Bárcenas Gabriel , Sanchez Isaac C. , Ortiz‐Estrada Ciro H. 
Published: September 2009

AbstractThe poly(1H,1H‐dihydrofluorooctyl methacrylate) behavior in supercritical CO2 was determined in relation to the emulsions formation phenomena in surfactants including a CO2‐philic chain and the particles formation process by RESS. The stability conditions show an obvious influence of both the polymer molecular weight and the CO2 density, which are in competence with the thermal effect. The results are consistent with a LCST behavior in function of the molecular weight reaching the θ condition that converges for both the upper critical solution (UCSD) and the critical flocculation density (CFD) for a colloidal system. By using Sanchez‐Lacombe equation of state, a solubility parameter is estimated and it confirms the affinity of the fluorinated polymer with CO2, this in agreement with the literature information that relates surface tension with cohesion energy. In the particles formation by RESS, it was determined that concentration, saturation degree and nozzle diameter have a direct influence on the particle morphology and size; meanwhile, temperature and pre‐expansion pressure are variables used to tune of saturation degree dependent phase behavior. Results show that particles of 200–400 nm can be obtained when 1%wt polymer, homogeneous solution and 130 µm nozzle diameter are used. Under those conditions, the nucleation process and the particles growth and size during precipitation can be controlled; the mechanism is analyzed in relation to the phase behavior.
Polymer Chain Collapse in Supercritical Fluids. 2. Experimental Evidence
Authors: Ortiz‐Estrada C. H. , Luna‐Bárcenas G. , Alvarado J. F. J. , González‐Alatorre G. , Sanchez I. C. , Ramírez N. Flores , García Salomón R. Vásquez , Castillo‐Tejas J. , Manero‐Brito O. 
Published: September 2009

AbstractThe phase behavior of a polymer in a supercritical solvent at the LCST equilibrium limits is described in this work, in the proximity of θ point, proposing the use of a conformational parameter, Ψ. The results obtained by molecular simulation in an NVT ensemble have been correlated by extensive, varied experimental information. The relationship between polymer/solvent solubility parameters has shown that the behavior of these systems is a function of the energetic structure‐interaction relationship between the polymer chain and the solvent. Ψ results in a generalized parameter indicative of the phase stability of the solution. At greater magnitudes, the solution becomes unstable, requiring elevated pressure to stabilize. However, stable solutions are found at lower pressures when Ψ approaches 1. The experimental evidence, together with the determination of the solubility parameter with the Sanchez‐Lacombe equation (also obtained from the literature) strengthens this observation. The analysis of the polar contribution on the Hansen Parameter (HSP) enables their effect to be studied in systems where high polar interactions between the polymer and solvent (as in the case of biopolymers) are expected.
Water‐Based Coatings Based on Mixtures of Acrylic Dispersions and Alkyd Emulsions
Authors: Kivit Patrick J. J. , Aramendia Esteban , Cabrera Amadeo A. , Ríos Lucero M. 
Published: September 2009

AbstractIn this work acrylic dispersions were mixed with alkyd emulsions to obtain coatings that lower the amount of volatile organic compounds (VOC) in surface coatings. The advantage of this approach is that the fast drying of the acrylic is combined with the good film properties of the alkyd. Films produced with an alkyd and a soft acrylic (AA1) did not exhibit good film properties. Whereas, films produced with a hard acrylic (SA1 and AA2) and a soft alkyd gave films with good appearance, appropriate drying times, superior pendulum hardness and promising values of gloss. VOC was calculated below 25 g/L. The novel mixtures may be applied as high gloss enamels for architectural coatings.
Polymeric Surfaces with Anticoagulant, Antifouling, and Antimicrobial Attributes
Authors: Yu Min , Urban Marek W. 
Published: September 2009

AbstractSummary: Recent advances in developments of anticoagulant, antifouling, and antimicrobial polymeric surfaces with the focus on surface modifications of polymeric materials as well as the influence of nanosize materials on interactions with biological systems are discussed. Controllable surface modifications using microwave plasma reactions in the presence of maleic anhydride provides a platform for attaching acid groups to inert polymeric surfaces which serves as a reactive anchor for further reactions. To effectively attach bioactive species inhibiting interactions with biological systems it is often necessary to attach a molecular spacer that facilitates mobility to terminal bioactive species.
Structural and Electrical Characterization of Isotactic PMMA Thin Films Deposited by Spin Coating
Authors: García B. , Ocampo M.A. , Luna‐Bárcenas G. , García R. , Mejia I. , Melgarejo F. Rodríguez , Loyola C. H. OR. Fernández , Catalán K. Sánchez , Ramírez N. Flores , García Salomón R. Vásquez , Ortiz‐Estrada C. , Garcia‐Gaitan B. , Zavala R. 
Published: September 2009

AbstractThin PMMA films have been studied extensively for their potential applications as membranes, microlithography and optical applications. PMMA has been recently use like gate dielectric film in OTFT. In this paper we present the structural and electrical characteristics of isotactic PMMA (i‐PMMA) thin films prepared by spin coating depositions. The electrical characterization was done using a simple capacitive structure to observe current density across dielectric film and voltage breakdown. The i‐PMMA films possess low current density across dielectric (1 × 10−8 A/cm2) and the breakdown voltage is higher than 100 V.
Strain Effect on the Electrical Conductivity of CB/SEBS and GP/SEBS Composites
Authors: Estrada Moreno Iván Alziri , Díaz Diaz Alberto , Mendoza Duarte Mónica Elvira , Ibarra Gómez Rigoberto 
Published: September 2009

AbstractCarbon black (CB) and Graphite (GP) were embedded in poly(styrene–ethylene/butylene–styrene) (SEBS) to form CB/SEBS and GP/SEBS composites. The electrical resistance was monitored in situ during tensile, compressive and dynamic mechanical tests, obtaining a correlation between the electrical response and strain. In the dynamic test the conductivity of the composites showed almost the same behavior than the elastic modulus, decreasing at deformations higher than 1%.
Neuropsychiatric symptoms in Parkinson's disease
Authors: Aarsland Dag , Marsh Laura , Schrag Anette 
Published: September 2009

AbstractNeuropsychiatric symptoms are common in Parkinson's disease, even at the earliest stages, and have important consequences for quality of life and daily functioning, are associated with increased carer burden and increased risk for nursing home admission. In addition to cognitive impairment, a wide range of neuropsychiatric symptoms have been reported. In this article, the epidemiology, clinical course, diagnosis, and management of some of the most common neuropsychiatric symptoms in PD are discussed: depression, anxiety, apathy, fatigue, and psychotic symptoms. Although much is known regarding the prevalence and course of these symptoms, the empirical evidence for how to manage these symptoms is limited at best. There is thus an urgent need for systematic studies for the pharmacological and non‐pharmacological management of these symptoms. © 2009 Movement Disorder Society
Parkinson's disease tremor is diminished with relaxation guided imagery
Authors: Schlesinger Ilana , Benyakov Orna , Erikh Ilana , Suraiya Suheir , Schiller Yitzhak 
Published: September 2009

AbstractPatients with Parkinson's disease (PD) may have pronounced tremor that exacerbates during stress. To determine whether PD tremor improves with relaxation guided imagery (RGI) and relaxing music. Twenty patients with PD with moderate to severe tremor participated in sessions where relaxation techniques were implemented. Tremor was objectively monitored using an accelerometer. RGI dramatically decreased tremor in all 20 patients (baseline 270.38 ± 85.82 vs. RGI 35.57 ± 43.90 movements per minute P < 0.0001). In 15 patients, RGI completely abolished tremor for 1–13 min. Average tremor activity remained significantly bellow baseline both 15 min and 30 min after RGI was discontinued (P < 0.001). Patients reported improvement lasting 2–14 hours (mean 6.8 ± 3.8). Relaxing music significantly reduced tremor but to a lesser degree than RGI (220.04 ± 106.53 movements per minute P = 0.01). Self‐relaxation had no significant effect on tremor. RGI can supplement conventional medical treatments for tremor in patients with PD on best medical treatment. © 2009 Movement Disorder Society
A novel method for systematic analysis of rigidity in Parkinson's disease
Authors: Endo Takayuki , Okuno Ryuhei , Yokoe Masaru , Akazawa Kenzo , Sakoda Saburo 
Published: September 2009

AbstractWe propose a novel system that analyzes the components of rigidity in Parkinson's disease (PD) usually perceived by physicians, in a very simple and systematic way for routine clinical practice. Our system is composed of two compact force sensors, a gyroscope, and EMG surface electrodes. Muscle tone was assessed in 24 healthy elderly subjects and 27 PD patients by passive extension and flexion of the elbow joint with ramp‐and‐hold trajectory. Torque and angle data in the dynamic phase were used to calculate “elastic coefficients” in extension and flexion, and the mean value of torque in each dynamic phase at each joint angle (defined as “Bias”) was also calculated. The muscle activity index in the static phase (EMG Index) was obtained for both biceps brachii (BB) and triceps brachii (TB) muscles. “Elastic coefficients,” sum of the “difference of Bias” and “EMG Index” for BB all correlated well with UPDRS score. Based on our results, Parkinsonian rigidity consists of both an “elastic” component and a “difference of Bias” component, and neurologists may assess greater rigidity when either one or both components are high in value. The EMG index was useful for differentiating PD patients with slight rigidity from healthy elderly adults. © 2009 Movement Disorder Society
Brain atrophy and white matter hyperintensities in early Parkinson's disease
Authors: Dalaker Turi O. , Larsen Jan P. , Bergsland Niels , Beyer Mona K. , Alves Guido , Dwyer Michael G. , Tysnes Ole‐Bjorn , Benedict Ralph H.B. , Kelemen Arpad , Bronnick Kolbjorn , Zivadinov Robert 
Published: September 2009

AbstractThe purpose of this research was to examine the extent of global brain atrophy and white matter hyperintensities (WMH) in early Parkinson's disease (PD) compared to normal controls (NC), to explore the relationship between the MRI variables and cognition in PD. In this multicenter study we included 155 PD patients (age 65.6 ± 9.1 years, disease duration 26.7 ± 19.9 months) and 101 age‐matched NC. On 3D‐T1‐WI, we calculated normalized brain volumes using SIENAX software. WMH volumes were assessed semiautomatically. In PD patients, correlation and regression analyses investigated the association between atrophy and WMH outcomes and global, attention‐executive, visuospatial, and memory cognitive functions. Regression analysis was controlled for age, education, depression score, motor severity, cerebrovascular risk, and sex. No significant MRI variable volume group differences were found. The models did not retain any of the imaging variables as significant predictors of cognitive impairment. There was no evidence of brain atrophy or higher WMH volume in PD compared to NC, and MRI volumetric measurements were not significant predictors of cognitive functions in PD patients. We conclude that global structural brain changes are not a major feature in patients with incident PD. © 2009 Movement Disorder Society
Loss of nocturnal blood pressure fall in various extrapyramidal syndromes
Authors: Schmidt Claudia , Berg Daniela , Herting  , Prieur Silke , Junghanns Susann , Schweitzer Katherine , Globas Christoph , Schöls Ludger , Reichmann Heinz , Ziemssen Tjalf 
Published: September 2009

AbstractCardiovascular autonomic dysfunction has frequently been reported in some patients with extrapyramidal syndromes, especially multiple system atrophy (MSA) but also Parkinson's disease (PD). However, there are only few reports on the prevalence of cardiovascular autonomic dysfunction progressive in supranuclear palsy (PSP). Moreover, the relation of detailed cardiovascular testing and easy to assess 24‐hour ambulatory blood pressure (BP) is not known. Our study evaluates 24‐hour ambulatory BP monitoring in patients with PD, PSP, MSA, and corresponding controls (Con) and relates the findings to the results of comprehensive cardiovascular autonomic testing. Twenty‐three patients with PD, 25 patients with PSP, 25 patients with MSA, and 26 corresponding controls were studied by 24‐hour ambulatory BP monitoring (ABPM) in comparison to cardiovascular autonomic testing. Patients with PD, PSP, and MSA presented frequently with a pathological nocturnal BP regulation (no decrease or even an increase of nocturnal BP) in comparison to the control group (PD 48%, PSP 40%, MSA 68% vs. Con 8%). In MSA and PD patients, the frequent pathological BP increase during night was closely correlated to orthostatic hypotension. Since loss of nocturnal BP fall is frequent in patients with extrapyramidal syndromes, even if they are free of subjective autonomic dysfunction, we recommend 24‐hour ABPM as an easy to perform screening test, especially if detailed autonomic testing is not available. Pathological loss of nocturnal BP fall may account for increased cardiovascular mortality in extrapyramidal syndromes. © 2009 Movement Disorder Society
NMR‐based metabonomics analysis of mouse urine and fecal extracts following oral treatment with the broad‐spectrum antibiotic enrofloxacin (Baytril)
Authors: Romick‐Rosendale Lindsey E. , Goodpaster Aaron M. , Hanwright Philip J. , Patel Neil B. , Wheeler Esther T. , Chona Deepika L. , Kennedy Michael A. 
Published: September 2009

AbstractThe human gastrointestinal tract is home to hundreds of species of bacteria and the balance between beneficial and pathogenic bacteria plays a critical role in human health and disease. The human infant, however, is born with a sterile gut and the complex gastrointestinal host/bacterial ecosystem is only established after birth by rapid bacterial colonization. Composition of newborn gut flora depends on several factors including type of birth (Ceasarian or natural), manner of early feeding (breast milk or formula), and exposure to local, physical environment. Imbalance in normal, healthy gut flora contributes to several adult human diseases including inflammatory bowel (ulcerative colitis and Crohn's disease) and Clostridium difficile associated disease, and early childhood diseases such as necrotizing enterocolitis. As a first step towards characterization of the role of gut bacteria in human health and disease, we conducted an 850 MHz 1H nuclear magnetic resonance spectroscopy study to monitor changes in metabolic profiles of urine and fecal extracts of 15 mice following gut sterilization by the broad‐spectrum antibiotic enrofloxacin (also known as Baytril). Ten metabolites changed in urine following enrofloxacin treatment including decreased acetate due to loss of microbial catabolism of sugars and polysaccharides, decreased trimethylamine‐N‐oxide due to loss of microbial catabolism of choline, and increased creatine and creatinine due to loss of microbial enzyme degradation. Eight metabolites changed in fecal extracts of mice treated with enrofloxacin including depletion of amino acids produced by microbial proteases, reduction in metabolites generated by lactate‐utilizing bacteria, and increased urea caused by loss of microbial ureases. Copyright © 2009 John Wiley & Sons, Ltd.
Micromelosides A–D, four new coumarins from the stem bark of Micromelum falcatum
Authors: Luo Xiongming , Qi Shuhua , Yin Hao , Xiao Zhihui , Zhang Si 
Published: September 2009

AbstractFour new coumarins, micromelosides A–D, together with four known coumarins were isolated from the stem bark of Micromelum falcatum. The complete assignments of the 1H and 13C NMR chemical shifts for these new compounds were achieved by means of 1D and 2D NMR techniques, including 1H‐1H COSY, HSQC, HMBC and NOE difference. Copyright © 2009 John Wiley & Sons, Ltd.
Electrical impedance myography: Background, current state, and future directions
Authors: Rutkove Seward B. 
Published: September 2009

AbstractElectrical impedance myography (EIM) is a non‐invasive technique for the evaluation of neuromuscular disease that relies upon the application and measurement of high‐frequency, low‐intensity electrical current. EIM assesses disease‐induced changes to the normal composition and architecture of muscle, including myocyte atrophy and loss, edema, reinnervation, and deposition of endomysial connective tissue and fat. With application of single‐frequency electrical current, EIM can be used to help grade the severity of neuromuscular disease. Assessing electrical impedance across a spectrum of applied frequencies and with current flow at multiple orientations relative to major muscle fiber direction can provide a more complete picture of the condition of muscle. EIM holds the promise of serving as an indicator of disease status. It may be useful in clinical trials and in monitoring effectiveness of treatment in individual patients; ultimately, it may also find diagnostic application. Ongoing efforts have been focused on obtaining a deeper understanding of the basic mechanisms of impedance change, studying EIM in a variety of clinical contexts, and further refining the methods of EIM data acquisition and analysis. Muscle Nerve, 2009
Evolution of the phenotype in a family with an LMNA gene mutation presenting with isolated cardiac involvement
Authors: Carboni Nicola , Porcu Maurizio , Mura Marco , Cocco Eleonora , Marrosu Giovanni , Maioli Maria A. , Solla Elisabetta , Tranquilli Stefania , Orrù Pierpaolo , Marrosu Maria G. 
Published: September 2009

AbstractThe aim of this study is to report the evolution of a phenotype in members of a single family carrying the heterozygous exon 1 c.178 C/G, p.Arg 60 Gly LMNA gene mutation. All mutated family members underwent neurological and cardiological assessments for a period ranging from 10 to 20 years. At onset, 4 affected adult members presented a phenotype that required pacemaker implantation. Three subjects underwent cardiac transplantation leading to long‐term survival in 2 of them. One of the 3 longest surviving relatives manifested late lipodystrophy, and the other 2 had lipodystrophy, insulin‐resistant diabetes, and distal peripheral neuropathy. The findings demonstrate that the exon 1 c.178 C/G, p.Arg 60 Gly LMNA gene mutation is associated with a novel phenotype featuring cardiac involvement followed by late lipodystrophy, diabetes, and peripheral axonal neuropathy. Muscle Nerve, 2010