bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenylaminopropyl‐functionalized stationary phase for open‐tubular capillary electrochromatography of alkaloids and aromatic acids
Authors: Lin Xucong , Tan Jingjing , Xu Shengmei , Xie Zenghong 
Published: May 2011

AbstractA multi‐functional open‐tubular (OT) column covalently modified with [3‐(phenylamino)propyl]trimethoxysilane (PPTMS) via a single‐step silanization reaction has been developed, and employed for alkaloids and aromatic acids analytes by CEC. Both anodic and cathodic EOF could be gained in the PPTMS‐bonded column, and anodic EOF was exhibited when the pH of running buffer was less than 8.0. Using thiourea as the EOF marker, a satisfactory column stability was denoted, and the RSD values for migration time and peak area were gained at 0.5 and 3.7% (intra‐day, n=5), 1.7 and 5.6% (inter‐day, n=3), 3.9 and 5.8% (column‐to‐ column, n=16 in four batches). With anodic EOF mode (pH=2.0 of 10 mmol/L phosphate buffer), favorable separations of cationic alkaloids (viz. uridine, adenosine, cytidine, adenine, cytosine) were successfully achieved with column efficiencies ranging from 95 000 to 187 000 plates/m, and the undesired adsorption on the inter‐wall of capillary column could be avoided. Besides, six anionic aromatic acids could be also separated efficiently in the co‐electroosmotic mode with anodic EOF. And high efficiencies ranged from 176 000 to 235 000 plates/m were gained with a good repeatability. PPTMS‐bonded capillary column might be used as an alternative functional medium to physical coating capillary column for the analyses of aromatic organic acids and bases.
Engineering of Phenylboronic Acid Based Glucose‐Sensitive Microgels with 4‐Vinylpyridine for Working at Physiological pH and Temperature
Authors: Farooqi Zahoor H. , Wu Weitai , Zhou Shuiqin , Siddiq Mohammad 
Published: May 2011

AbstractGlucose‐sensitive p(NIPAM‐4‐VP‐PBA) microgels with different 4‐VP content are synthesized by the functionalization of p(NIPAM‐4‐VP‐AA) microgels with 3‐aminophenylboronic acid. The glucose‐, pH‐, and thermosensitive behavior of the microgels are investigated using DLS. The feeding content of the hydrophilic 4‐VP group increases the hydrodynamic radius and volume phase transition temperature of the resultant microgel. The effect of 4‐VP content on hydrodynamic radius and volume phase transition is systematically studied at different pH values. The effect of 4‐VP content on the glucose sensitivity is studied at physiological pH and temperature. The Lewis base moiety 4‐VP adjusts the working pH of the PBA‐based glucose‐responsive microgel to physiological values. magnified image
Poly(ethylene glycol)‐Coated Fe3O4 Nanoparticles by UV‐Thiol‐Ene Addition of PEG Dithiol on Vinyl‐Functionalized Magnetite Surface
Authors: Amici Julia , Allia Paolo , Tiberto Paola , Sangermano Marco 
Published: May 2011

AbstractMagnetite nanoparticles are synthesized and functionalized with vinyl groups (by silanization reaction with VTMS) and further coated with poly(ethylene glycol) dithiol under UV activation via thiol‐ene addition. TEM analysis is in a good agreement with DLS analyses and shows that by vinyl functionalization and following PEG coating it was possible to achieve nanometer‐sized particles with an average size of about 20–50 nm, well distributed and not‐aggregated. Superparamagnetic‐like behavior of coated Fe3O4 nanoparticles, which is typically looked for in biomedical applications, is ensured by the Brownian motion of the magnetic NPs in the ferrofluid. The polymeric coating does not modify the magnetic response of the magnetite nanoparticles. magnified image
Quantification of changes in muscle from individuals with and without mitochondrial disease
Authors: Sleigh Kerry , Ball Susan , Hilton David A. 
Published: May 2011

AbstractIntroduction: Muscle biopsy is used in the diagnosis of mitochondrial disorders. There are limited data on the normal ranges, so interpretation of findings can be difficult. Methods: We evaluated the percentage of fibers showing mitochondrial abnormalities using Gomori trichrome staining, succinate dehydrogenase, and cytochrome oxidase histochemistry in autopsy samples taken from 45 individuals without evidence of muscle disease and biopsies from 17 patients with mitochondrial disorders. Results: In controls, mitochondrial abnormalities were rare before the fifth decade, and most had <0.1% abnormal fibers. The proportion of abnormal fibers increased with age and was higher in deltoid than quadriceps. Most patients with mitochondrial disorders had >0.5% abnormal fibers. Conclusions: Although some patients with mitochondrial disease have very few muscle fibers that show mitochondrial abnormalities, a rate of abnormality of >0.5% fibers, in the absence of a primary muscle disease this should raise the possibility of a mitochondrial disorder. Muscle Nerve, 2011
Crossed spinal soleus muscle communication demonstrated by H‐reflex conditioning
Authors: Stubbs Peter W. , Nielsen Jørgen F. , Sinkjær Thomas , Mrachacz‐Kersting Natalie 
Published: May 2011

AbstractIntroduction: A conditioning volley to the ipsilateral tibial nerve (iTN) inhibits contralateral soleus (cSOL) electromyographic activity at latencies of 37–41 ms. This is evidence for spinal muscular communication in opposing limbs. The aim of our study was to determine whether the cSOL H‐reflex would be inhibited in a similar manner. Methods: Thirteen subjects participated in two experiments: (1) stimuli delivered to the iTN at 85% of the maximal peak‐to‐peak M‐wave (85% M‐max) with a pre‐contracted cSOL; (2) 510 stimuli delivered at 85% M‐max to the iTN with a test volley delivered to the contralateral tibial nerve at interstimulus intervals of −6 to 100 ms. Results: Significant inhibition was observed in the cSOL H‐reflex when conditioning stimuli were delivered 3–33 ms before the test H‐reflex. Conclusions: The activity of this spinal pathway can be quantified using H‐reflex conditioning to provide a controlled model for further studies of this response. Muscle Nerve, 2011
Analysis of continuous diaphragm electromyographic signal: Results from a patient with amyotrophic lateral sclerosis
Authors: Katzberg Hans D. , Barros Daniel F. , Widrow Bernard , Cho Charles S. , So Yuen T. 
Published: May 2011

AbstractIntroduction: Analysis of continuous diaphragm electromyography (dEMG) has not been well studied. We describe a system of analyzing continuous dEMG using implanted electrodes.Methods: dEMG signal was acquired via two pairs of electrodes near the diaphragm motor points. Raw bursts of dEMG signal were compared to externally captured electrocardiogram (ECG) using adaptive filtering in order to remove cardiac contamination. Differential energy levels were used to identify each dEMG burst, and average amplitude and area values from both hemidiaphragms were aggregated and averaged for the duration of the recording.Results: A 64‐year‐old patient with amyotrophic lateral sclerosis underwent three serial dEMG studies every 6 months. An average of three tracings were collected per visit, and all had excellent intertest reliability (κ > 0.8). Average dEMG area correlated with forced vital capacity and mean inspiratory pressure (r2> 0.9).Conclusions: The approach described represents a comprehensive method for capturing and analyzing continuous diaphragm EMG signal. Muscle Nerve, 2011
Electrodiagnostic consultation and identification of neuromuscular conditions in persons with diabetes
Authors: Sohn Min‐Woong , Whittle Jeff , Pezzin Liliana E. , Miao Haiyan , Dillingham Timothy R. 
Published: May 2011

AbstractIntroduction: Although the American Association of Neuromuscular and Electrodiagnostic Medicine recommends that electrodiagnostic procedures should be performed by physicians with specialty training, these procedures are increasingly being performed by non‐specialists. Methods: We used a nationally representative sample of Medicare beneficiaries with diabetes who used electrodiagnostic services in 2006 to examine whether specialists and non‐specialists were different in the rates of identifying common neuromuscular conditions. Results: Specialists (neurologists and physiatrists) performed 62% of electrodiagnostic consultations; non‐specialist physicians and non‐physicians performed 31% and 5%, respectively. After adjusting for age, race/ethnicity, diabetes severity, and comorbidities, specialists were 1.26–9 times more likely than non‐physicians to diagnose polyneuropathy, lumbosacral radiculopathy, cervical radiculopathy, carpal tunnel syndrome, and ulnar neuropathy. Almost 80% of electrodiagnostic studies performed by specialists included electromyography testing; fewer than 13% by non‐specialists did. Conclusions: Inadequate use of electromyography and fewer specific diagnoses suggest that many non‐specialists perform insufficiently comprehensive electrodiagnostic studies. Muscle Nerve, 2011
A note on a generalization of eigenvector centrality for bipartite graphs and applications
Authors: Daugulis Peteris 
Published: May 2011

AbstractEigenvector centrality is a linear algebra based graph invariant used in various rating systems such as webpage ratings for search engines. A generalization of the eigenvector centrality invariant is defined which is motivated by the need to design rating systems for bipartite graph models of time‐sensitive and other processes. The linear algebra connection and some applications are described. © 2011 Wiley Periodicals, Inc. NETWORKS, 2012
An ETD Crank‐Nicolson method for reaction‐diffusion systems
Authors: Kleefeld B. , Khaliq A.Q.M. , Wade B.A. 
Published: May 2011

AbstractA novel Exponential Time Differencing Crank‐Nicolson method is developed which is stable, second‐order convergent, and highly efficient. We prove stability and convergence for semilinear parabolic problems with smooth data. In the nonsmooth data case, we employ a positivity‐preserving initial damping scheme to recover the full rate of convergence. Numerical experiments are presented for a wide variety of examples, including chemotaxis and exotic options with transaction cost. © 2011Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012
Superconvergence for a time‐discretization procedure for the mixed finite element approximation of miscible displacement in porous media
Authors: Cheng Aijie , Wang Kaixin , Wang Hong 
Published: May 2011

AbstractA time‐stepping procedure is established and analyzed for the problem of miscible displacement in porous medium. The fluid velocity based on mixed element method is post‐processed by interpolation along Gauss lines. Error analysis shows that this procedure has a superconvergence error bound O(h) with respect to the parameter hp, which is one order higher than the conventional Galerkin or mixed finite element procedures. Compared with the results in the references, the parameter constraint conditions in this article are obviously relaxed. © 2011Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012
Utilizing Medicare claims data for real‐time drug safety evaluations: is it feasible?,
Authors: Hartzema Abraham G. , Racoosin Judith A. , MaCurdy Thomas E. , Gibbs Jonathan M. , Kelman Jeffrey A. 
Published: May 2011

ABSTRACTPurposeThe Centers for Medicare & Medicaid Services claims comprise an administrative database of beneficiary‐specific clinical information. This study evaluates the impacts of (i) claim information updates (claims adjudication) and (ii) delay in claim processing (claims delay) on real‐time evaluation of health service and drug safety signals using the Medicare database.MethodsUsing Medicare claims data accumulated through May 2009 on health services rendered in 2006 and drugs dispensed in 2007, this study measures the frequency with which clinical information changes in the database as a result of (i) claims adjudication and (ii) claims delay.ResultsOver 85% of health services claims were processed within 8 weeks after the date of service, and 72% of drug claims were processed within 3 months after the dispense date. Clinical information changed for no more than 3% of unique claim groups in inpatient hospital, outpatient institutional, physician's office, and prescription drug Medicare claim settings.ConclusionsClaims delay is consistent across time and is minimal. Claims adjudication does not substantially impact the content of clinical information in the Medicare claims database. Therefore, the Medicare claims database provides consistent information regarding health services and prescription drugs in a manner that is prompt enough to facilitate medical product safety evaluations in real time. Copyright © 2011 John Wiley & Sons, Ltd.
Systematic review of peptic ulcer disease incidence rates: do studies without validation provide reliable estimates?
Authors: Lin Kueiyu Joshua , García Rodríguez Luis A. , Hernández‐Díaz Sonia 
Published: May 2011

ABSTRACTPurposeIncidence rate (IR) estimates for peptic ulcer disease (PUD) vary widely among studies. We conducted a systematic review to quantify and examine the discrepancies.MethodsOf 4780 articles identified from PubMed and EMBASE databases, 31 published in the last three decades that had reported IRs of PUD in the general population were included. Random effects meta‐analysis and meta‐regression were performed to calculate pooled estimates and to identify sources of heterogeneity.ResultsThe pooled IR estimate per 1000 person‐years was 0.90 (95% confidence interval: 0.78–1.04) for uncomplicated PUD, 0.57 (0.49–0.65) for peptic ulcer bleeding, 0.10 (0.08–0.13) for gastrointestinal perforations, and 3.18 (2.05–4.92) for nonspecific PUD. Within specific outcomes definitions, IR estimates were significantly lower in studies with restriction to hospitalized cases, case validation, and case ascertainment directly from hospital or clinical sources versus computerized health care databases. Younger age, female sex, and later calendar time were also associated with lower PUD incidence.ConclusionsWe found that the IR of uncomplicated PUD was in the order of one case per 1000 person‐years in the general population, and that the IR of peptic ulcer complications was around 0.7 cases per 1000 person‐years. Comparisons of IR estimates among studies need to take into account disease definition and other study characteristics, particularly whether outcome validation was performed in computerized claims. The use of claims to identify PUD cases might overestimate the IR by around 45%. Copyright © 2011 John Wiley & Sons, Ltd.
Functional copolymer/organo‐montmorillonite nanoarchitectures. IX. Synthesis and nanostructure–morphology–thermal behaviour relationships of poly[(maleic anhydride)‐alt‐(acrylic acid)]/organo‐ montmorillonite nanocomposites
Authors: Rzayev Zakir MO , Şenol Burcu , Denkbaş Amir B 
Published: May 2011

AbstractFunctional copolymer/clay hybrids were synthesized by radical‐initiated interlamellar copolymerization of maleic anhydride/maleic acid and acrylic acid with 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride as a water‐soluble ionizable radical initiator in the presence of reactive (octadecylamine‐montmorillonite (ODA‐MMT)) and non‐reactive (dimethyldodecylammonium‐montmorillonite) organoclays at 60 °C in aqueous medium under nitrogen atmosphere. The monomers were dissolved in aqueous medium, and the two types of clay particles used were easily dissolved and dispersed partially swollen, respectively, in deionized water. Structure, thermal behaviour and morphology of the synthesized nanocomposites were investigated using Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning and transmission electron microscopy. It is demonstrated that intercalative copolymerization proceeds via ion exchange between organoclays and carboxylic groups of monomers/polymers, which essentially improves interfacial interactions of polymer matrix and clay layers through strong hydrogen bonding. In the case of intercalative copolymerization in the presence of ODA‐MMT clay, a similar improvement is provided by in situ hydrogen bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine groups of ODA‐MMT. The nanocomposites exhibit higher degree of intercalation/exfoliation of copolymer chains, improved thermal properties and fine dispersed morphology. Copyright © 2011 Society of Chemical Industry
Synthesis and photophysical properties of soluble low‐bandgap thienothiophene polymers with various alkyl side‐chain lengths
Authors: Bae Woo Jin , Scilla Christopher , Duzhko Volodimyr V. , Ho Jo Won , Coughlin E. Bryan 
Published: May 2011

AbstractWe report the facile synthesis and characterization of a class of thienothiophene polymers with various lengths of alkyl side chains. A series of 2‐alkylthieno[3,4‐b]thiophene monomers (Ttx) have been synthesized in a two‐step protocol in an overall yield of 28–37%. Poly(2‐alkylthieno[3,4‐b]thiophenes) (PTtx, alkyl: pentyl, hexyl, heptyl, octyl, and tridecyl) were synthesized by oxidative polymerization with FeCl3 or via Grignard metathesis (GRIM) polymerization methods. The polymers are readily soluble in common organic solvents. The polymers synthesized by GRIM polymerization method (PTtx‐G) have narrower molecular weight distribution (Đ) with lower molecular weight (Mn) than those synthesized by oxidative polymerization (PTtx‐O). The band structures of the polymers with various lengths of alkyl side chains were investigated by UV–vis spectroscopy, cyclic voltammetry, and ultraviolet photoelectron spectroscopy. These low‐bandgap polymers are good candidates for organic transistors, organic light‐emitting diodes, and organic photovoltaic cells. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Ethylene polymerization using novel titanium catalytic precursors bearing N,N‐dialkylcarbamato ligands
Authors: Forte Claudia , Hayatifar Mohammad , Pampaloni Guido , Galletti Anna Maria Raspolli , Renili Filippo , Zacchini Stefano 
Published: May 2011

AbstractPolymerization catalysts based on N,N‐dialkylcarbamato complexes of titanium(IV) appear particularly interesting, because these novel catalytic precursors are rather cheap and easy to synthesize and handle. This contribution reports ethylene polymerization behavior of titanium(IV) complexes of general formula Ti(O2CNR2)4 R = Me (I) and Et (II) and TiCl2(O2CNMe2)2 (III). These precursors in conjunction with methylaluminoxane resulted active catalysts for the polymerization of ethylene, affording high‐density polyethylene with limited branch content. The influence of the polymerization parameters was studied with particular reference to the type of catalyst components, solvent, temperature, monomer concentration, and Al/Ti ratio. The nature of the solvent appears crucial for catalytic performances: when toluene was replaced by chlorobenzene, a significant increase of the productivity was ascertained. The obtained polymers were characterized by DSC, size exclusion chromatography, FTIR, and NMR techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of the stirring speed and CaCl2 concentration on the nano‐object morphologies obtained via RAFT‐mediated aqueous emulsion polymerization in the presence of a water‐soluble macroRAFT agent
Authors: Boissé Stéphanie , Rieger Jutta , Pembouong Gaëlle , Beaunier Patricia , Charleux Bernadette 
Published: May 2011

AbstractAqueous emulsion polymerizations of styrene were performed in the presence of a macromolecular reversible addition‐fragmentation chain transfer (RAFT) agent (macroRAFT) composed of acrylic acid (AA) and poly(ethylene oxide) methyl ether acrylate (PEOA), end‐capped by a reactive dodecyl trithiocarbonate group (P(AA‐co‐PEOA)‐TTC). The influence of the stirring speed or the presence of different amounts of a divalent salt, CaCl2, were investigated in this polymerization‐induced self‐assembly process, in which spherical and nonspherical nano‐objects were formed upon the synthesis of amphiphilic diblock copolymers in situ. It appeared that the addition of CaCl2 led to the controlled formation of different nano‐objects such as spheres, fibers or vesicles, whereas an appropriate stirring speed was required for the formation of nanofibers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and electroluminescence properties of white‐light single polyfluorenes with high‐molecular weight by click reaction
Authors: Lo Chih‐Nan , Hsu Chain‐Shu 
Published: May 2011

AbstractWe reported a new way to synthesize single‐chain white light‐emitting polyfluorene (WPF) with an increased molecular weight using azide‐alkyne click reaction. Four basic polymers with specific end‐capping, which exhibited high‐glass transition temperatures (Tg > 100 °C) and excellent thermal stability, were used as foundations of the WPF's synthesis; a blue‐light polymer (PFB2) end‐capped with azide groups can easily react with acetylene end‐capped polymers (PFB1, PFG1, and PFR1, which are emitting blue‐, green‐ and red‐light, respectively) to form triazole‐ring linkages in polar solvents such as N,N‐dimethylforamide/toluene co‐solvent at moderate temperature of 100 °C, even without metal‐catalyst. Several WPFs that consist of these four basic polymers in certain ratios were derived, and the polymer light‐emitting diode device based on the high‐molecular weight WPF was achieved and demonstrated a maximum brightness of 7551 cd/m2 (at 12.5 V) and a maximum yield of 5.5 cd/A with Commission Internationale de l'Eclairage coordinates of (0.30, 0.33) using fine‐tuned WPF5 as emitting material. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
High‐Rate Deposition of Electrochromic Organotungsten Oxide Thin Films for Flexible Electrochromic Devices by Atmospheric Pressure Plasma Jet: The Effect of Substrate Distance
Authors: Lin Yung‐Sen , Wu Siang‐Syuan , Tsai Tsung‐Hsien 
Published: May 2011

AbstractHigh‐rate deposition of electrochromic organotungsten oxide (WOxCy) films onto flexible PET (polyethylene terephthalate)/ITO (indium tin oxide) substrates by atmospheric pressure‐plasma enhanced chemical vapor deposition (AP‐PECVD) with atmospheric pressure plasma jet (APPJ) under various substrate distances is investigated. A precursor (tungsten carbonyl, W(CO)6, TC) vapor, carried by argon gas, is injected into air plasma torch for the synthesis of WOxCy films. Uniform light modulation up to 1 cm wide on PET/ITO/WOxCy is produced, while the moving PET/ITO substrate is exposed to a 0.3 cm diameter plasma torch at room temperature (≈23 °C) and atmospheric pressure. The porous APPJ‐synthesized WOxCy films result in fast responses using potential steps for coloration of 11.5 s at −1V and bleaching of 7.2 s at +1V, respectively. APPJ‐synthesized WOxCy films offer noteworthy electrochromic performance in light modulation with up to 73.0% of transmittance variation, optical density change of 0.72 and coloration efficiency of 67.7 cm2 · C−1 at a wavelength of 800 nm. magnified image