bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic source imaging for the surgical evaluation of electroencephalography-confirmed secondary bilateral synchrony in intractable epilepsy
Authors: Chang Edward F. , Nagarajan Srikantan S. , Mantle Mary , Barbaro Nicholas M. , Kirsch Heidi E.
Published: July 2009

Object

Routine scalp electroencephalography (EEG) cannot always distinguish whether generalized epileptiform discharges are the result of primary bilateral synchrony or secondary bilateral synchrony (SBS) from a focal origin; this is an important distinction because the latter may be amenable to resection. Whole-head magnetoencephalography (MEG) has superior spatial resolution compared with traditional EEG, and can potentially elucidate seizure foci in challenging epilepsy cases in which patients are undergoing evaluation for surgery.

Methods

Sixteen patients with medically intractable epilepsy in whom SBS was suspected were referred for magnetic source (MS) imaging. All patients had bilateral, synchronous, widespread, and most often generalized spike-wave discharges on scalp EEG studies, plus some other clinical (for example, seizure semiology) or MR imaging feature (for example, focal lesion) suggesting focal onset and hence possible surgical candidacy. The MS imaging modality is the combination of whole-head MEG and parametric reconstruction of corresponding electrical brain sources. An MEG and simultaneous EEG studies were recorded with a 275-channel whole-head system. Single-equivalent current dipoles were estimated from the MEG data, and dipole locations and orientations were superimposed on patients' MR images.

Results

The MS imaging studies revealed focal dipole clusters in 12 (75%) of the 16 patients, of which a single dipole cluster was identified in 7 patients (44%). Patient age, seizure type, duration of disease, video-EEG telemetry, and MR imaging results were analyzed to determine factors predictive of having clusters revealed on MS imaging. Of these factors, only focal MR imaging anatomical abnormalities were associated with dipole clusters (chi-square test, p = 0.03). Selective resections (including the dipole cluster) in 7 (87%) of 8 patients resulted in seizure-free or rare seizure outcomes (Engel Classes I and II).

Conclusions

Magnetic source imaging may provide noninvasive anatomical and neurophysiological confirmation of localization in patients in whom there is a suspicion of SBS (based on clinical or MR imaging data), especially in those with an anatomical lesion. Identification of a focal seizure origin has significant implications for both resective and nonresective treatment of intractable epilepsy.
Radiation-induced rhabdomyosarcoma of the brainstem in a patient with neurofibromatosis Type 2
Authors: Carlson Matthew L. , Babovic-Vuksanovic Dusica , Messiaen Ludwine , Scheithauer Bernd W. , Neff Brian A. , Link Michael J.
Published: July 2009

Neurofibromatosis Type 2 (NF2) is a rare autosomal dominant disorder characterized by the development of benign tumors of the peripheral nervous system and the CNS, including schwannomas, meningiomas, and ependymomas. The gene responsible for the development of NF2 acts as a tumor suppressor gene. Stereotactic radiotherapy (SRT) or single-fraction stereotactic radiosurgery has been increasingly used in the past decades to treat benign tumors in patients with NF2. These radiotherapy methods are less invasive and can be potentially used to treat multiple tumors in a single session. The risk of inducing malignancy is unclear. Few reports exist of malignant peripheral nerve sheath tumors, meningiomas, or ependymomas occurring after SRT or stereotactic radiosurgery in patients with NF2. The authors present the first documented case of rhabdomyosarcoma following SRT for multiple NF2-associated schwannomas. Compared with patients with sporadic tumors, NF2 patients having a germline tumor suppressor gene defect may be more prone to secondary malignancies after treatment involving radiation therapy.
Introduction: Computer Simulations in Social Epistemology
Authors: Douven Igor
Published: July 2009

Over recent decades, computer simulations have become a common tool among practitioners of the social sciences. They have been utilized to study such diverse phenomena as the integration and segregation of different racial groups, the emergence and evolution of friendship networks, the spread of gossip, fluctuations of housing prices in an area, the transmission of social norms, and many more. Philosophers of science and others interested in the methodological status of these studies have identified a number of distinctive virtues of the use of computer simulations. For instance, it has been generally appreciated that as simulations require the formulation of an explicit algorithm, they foster precision and clarity about whatever conceptual issues are involved in the study. The value of computer simulations as a heuristic tool for developing hypotheses, models, and theories has also been recognized, as has been the fact that they can serve as a substitute for real experiments. This is especially useful in the social domain, given that human beings cannot be freely manipulated at the discretion of the experimenter (for both points, see Hartmann 1996). However, the main virtue of computer simulations is generally believed to be that they are able to deal with the complexities that arise when many elements interact in a highly dynamic system and which often evade an exact formal analysis (see, e.g., Humphreys 1991).
Open Problems in Universal Induction & Intelligence
Authors: Hutter Marcus
Published: July 2009

Specialized intelligent systems can be found everywhere: finger print, handwriting, speech, and face recognition, spam filtering, chess and other game programs, robots, et al. This decade the first presumably complete mathematical theory of artificial intelligence based on universal induction-prediction-decision-action has been proposed. This informationtheoretic approach solidifies the foundations of inductive inference and artificial intelligence. Getting the foundations right usually marks a significant progress and maturing of a field. The theory provides a gold standard and guidance for researchers working on intelligent algorithms. The roots of universal induction have been laid exactly half-a-century ago and the roots of universal intelligence exactly one decade ago. So it is timely to take stock of what has been achieved and what remains to be done. Since there are already good recent surveys, I describe the state-of-the-art only in passing and refer the reader to the literature. This article concentrates on the open problems in universal induction and its extension to universal intelligence.
Tobacco Smoke Exposure and Levels of Urinary Metals in the U.S. Youth and Adult Population: The National Health and Nutrition Examination Survey (NHANES) 1999–2004
Authors: Richter Patricia A. , Bishop Ellen E. , Wang Jiantong , Swahn Monica H.
Published: July 2009

We assessed 12 urine metals in tobacco smoke-exposed and not exposed National Health and Nutrition Examination Survey participants. Our analysis included age, race/ethnicity, and poverty status. Gender and racial/ethnic differences in cadmium and lead and creatinine-adjusted and unadjusted data for group comparisons are presented. Smokers’ had higher cadmium, lead, antimony, and barium levels than nonsmokers. Highest lead levels were in the youngest subjects. Lead levels among adults with high second-hand smoke exposure equaled smokers. Older smokers had cadmium levels signaling the potential for cadmium-related toxicity. Given the potential toxicity of metals, our findings complement existing research on exposure to chemicals in tobacco smoke.
Applications of Isothermal Titration Calorimetry in Biophysical Studies of G-quadruplexes
Authors: Pagano Bruno , Mattia Carlo Andrea , Giancola Concetta
Published: July 2009

G-quadruplexes are higher-order nucleic acids structures formed by G-rich sequences that are stabilized by tetrads of hydrogen-bonded guanine bases. Recently, there has been growing interest in the study of G-quadruplexes because of their possible involvement in many biological processes. Isothermal titration calorimetry (ITC) has been proven to be a useful tool to study the energetic aspects of G-quadruplex interactions. Particularly, ITC has been applied many times to determine the thermodynamic properties of drug-quadruplex interactions to screening among various drugs and to address drug design. In the present review, we will focus on the ITC studies of G-quadruplex structures and their interaction with proteins and drugs and the most significant results will be discussed.
Hyaluronan Benzyl Ester as a Scaffold for Tissue Engineering
Authors: Vindigni Vincenzo , Cortivo Roberta , Iacobellis Laura , Abatangelo Giovanni , Zavan Barbara
Published: July 2009

Tissue engineering is a multidisciplinary field focused on in vitro reconstruction of mammalian tissues. In order to allow a similar three-dimensional organization of in vitro cultured cells, biocompatible scaffolds are needed. This need has provided immense momentum for research on “smart scaffolds” for use in cell culture. One of the most promising materials for tissue engineering and regenerative medicine is a hyaluronan derivative: a benzyl ester of hyaluronan (HYAFF®). HYAFF® can be processed to obtain several types of devices such as tubes, membranes, non-woven fabrics, gauzes, and sponges. All these scaffolds are highly biocompatible. In the human body they do not elicit any adverse reactions and are resorbed by the host tissues. Human hepatocytes, dermal fibroblasts and keratinocytes, chondrocytes, Schwann cells, bone marrow derived mesenchymal stem cells and adipose tissue derived mesenchymal stem cells have been successfully cultured in these meshes. The same scaffolds, in tube meshes, has been applied for vascular tissue engineering that has emerged as a promising technology for the design of an ideal, responsive, living conduit with properties similar to that of native tissue.
Molecular Characterization of Tb, a New Approach for an Ancient Brucellaphage
Authors: Zhu Cai-Zhong , Xiong Hong-Yan , Han Jing , Cui Bu-Yun , Piao Dong-Ri , Li Ya-Fei , Jiang Hai , Ren Qian , Ma Xiang-Yu , Chai Ya-Ming , Huang Xia , Zhao Hong-Yan , Li Lan-Yu
Published: July 2009

Tb (Tbilisi), the reference Brucellaphage strain, was classified as a member of the Podoviridae family with icosahedral capsids (57 ± 2 nm diameter) and short tails (32 ± 3 nm long). Brucellaphage DNA was double stranded and unmethylated; its molecular size was 34.5 kilobase pairs. Some sequences were found through RAPD analysis, TA cloning technology, and structural proteins were observed by using SDS-PAGE. Thus, the results have laid the foundation for the wider use of Brucellaphage’s basic mechanisms and practical applications.
A New Synthetic Compound, 2-OH, Enhances Interleukin-2 and Interferon-γ Gene Expression in Human Peripheral Blood Mononuclear Cells
Authors: Chou Shiu-Huey , Chou Shang-Shing P. , Liew Yih-Fong , Leu Jyh-Yih , Wang Su-Jane , Huang Rwei-Fen S. , Tzeng Woan-Fang , Kuo Yuh-Chi
Published: July 2009

A new synthetic compound, 6-hydroxy-2-tosylisoquinolin-1(2H)-one (2-OH), was selected for immunopharmacological activity tests. The effects of 2-OH on human peripheral blood mononuclear cell (PBMC) proliferation were determined by tritiated thymidine uptake. Compared to phytohemagglutinin (PHA; 5 μg/mL) stimulation, 2-OH significantly enhanced PBMC proliferation in a dose-dependent manner. The 50% enhancement activity (EC50) for 2-OH was 4.4±0.1 μM. In addition, effects of 2-OH on interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in PBMC were determined by enzyme immunoassay. Results demonstrated that 2-OH stimulated IL-2 and IFN-γ production in PBMC. Data from reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR indicated that IL-2 and IFN-γ mRNA expression in PBMC could be induced by 2-OH. Therefore, 2-OH enhanced IL-2 and IFN-γ production in PBMC by modulation their gene expression. We suggest that 2-OH may be an immunomodulatory agent.
Salivary Aldehyde Dehydrogenase: Activity towards Aromatic Aldehydes and Comparison with Recombinant ALDH3A1
Authors: Giebułtowicz Joanna , Wolinowska Renata , Sztybor Anna , Pietrzak Monika , Wroczyński Piotr , Wierzchowski Jacek
Published: July 2009

A series of aromatic aldehydes was examined as substrates for salivary aldehyde dehydrogenase (sALDH) and the recombinant ALDH3A1. Para-substituted benzaldehydes, cinnamic aldehyde and 2-naphthaldehydes were found to be excellent substrates, and kinetic parameters for both salivary and recombinant ALDH were nearly identical. It was demonstrated that for the fluorogenic naphthaldehydes the only produced reaction product after incubation in saliva is the carboxylate.
Steroidal Lactones from Withania somnifera, an Ancient Plant for Novel Medicine
Authors: Mirjalili Mohammad Hossein , Moyano Elisabeth , Bonfill Mercedes , Cusido Rosa M. , Palazón Javier
Published: July 2009

Withania somnifera, commonly known as Ashwagandha, is an important medicinal plant that has been used in Ayurvedic and indigenous medicine for over 3,000 years. In view of its varied therapeutic potential, it has also been the subject of considerable modern scientific attention. The major chemical constituents of the Withania genus, the withanolides, are a group of naturally occurring C28-steroidal lactone triterpenoids built on an intact or rearranged ergostane framework, in which C-22 and C-26 are appropriately oxidized to form a six-membered lactone ring. In recent years, numerous pharmacological investigations have been carried out into the components of W. somnifera extracts. We present here an overview of the chemical structures of triterpenoid components and their biological activity, focusing on two novel activities, tumor inhibition and antiangiogenic properties of withaferin A and the effects of withanolide A on Alzheimer's disease. The most recent attempts in biotechnological production of withanolides are also discussed.
Radiometric Calibration of Terrestrial Laser Scanners with External Reference Targets
Authors: Kaasalainen Sanna , Krooks Anssi , Kukko Antero , Kaartinen Harri
Published: July 2009

The intensity data produced by terrestrial laser scanners has become a topic of increasing interest in the remote sensing community. We present a case study of radiometric calibration for two phase-shift continuous wave (CW) terrestrial scanners and discuss some major issues in correcting and applying the intensity data, and a practical calibration scheme based on external reference targets. There are differences in the operation of detectors of different (although similar type) instruments, and the detector effects must be known in order to calibrate the intensity data into values representing the target reflectance. It is, therefore, important that the effects of distance and target reflectance on the recorded intensity are carefully studied before using the intensity data from any terrestrial laser scanner.
Design and Implementation of an Architectural Framework for Web Portals in a Ubiquitous Pervasive Environment
Authors: Raza Muhammad Taqi , Yoo Seung-Wha , Kim Ki-Hyung , Joo Seong-Soon , Jeong Wun-Cheol
Published: July 2009

Web Portals function as a single point of access to information on the World Wide Web (WWW). The web portal always contacts the portal’s gateway for the information flow that causes network traffic over the Internet. Moreover, it provides real time/dynamic access to the stored information, but not access to the real time information. This inherent functionality of web portals limits their role for resource constrained digital devices in the Ubiquitous era (U-era). This paper presents a framework for the web portal in the U-era. We have introduced the concept of Local Regions in the proposed framework, so that the local queries could be solved locally rather than having to route them over the Internet. Moreover, our framework enables one-to-one device communication for real time information flow. To provide an in-depth analysis, firstly, we provide an analytical model for query processing at the servers for our framework-oriented web portal. At the end, we have deployed a testbed, as one of the world’s largest IP based wireless sensor networks testbed, and real time measurements are observed that prove the efficacy and workability of the proposed framework.
Use of the Plasma Spectrum RMS Signal for Arc-Welding Diagnostics
Authors: Mirapeix Jesus , Cobo Adolfo , Fuentes Jose , Davila Marta , Etayo Juan  Maria , Lopez-Higuera Jose-Miguel
Published: July 2009

A new spectroscopic parameter is used in this paper for on-line arc-welding quality monitoring. Plasma spectroscopy applied to welding diagnostics has typically relied on the estimation of the plasma electronic temperature, as there is a known correlation between this parameter and the quality of the seams. However, the practical use of this parameter gives rise to some uncertainties that could provoke ambiguous results. For an efficient on-line welding monitoring system, it is essential to prevent the appearance of false alarms, as well as to detect all the possible defects. In this regard, we propose the use of the root mean square signal of the welding plasma spectra, as this parameter will be proven to exhibit a good correlation with the quality of the resulting seams. Results corresponding to several arc-welding field tests performed on Inconel and titanium specimens will be discussed and compared to non-destructive evaluation techniques.
Periodic TiO2 Nanorod Arrays with Hexagonal Nonclose‐Packed Arrangements: Excellent Field Emitters by Parameter Optimization
Authors: Li Yue , Fang Xiaosheng , Koshizaki Naoto , Sasaki Takeshi , Li Liang , Gao Shuyan , Shimizu Yoshiki , Bando Yoshio , Golberg Dmitri
Published: July 2009

Periodic TiO2 nanorod arrays with hexagonal nonclose‐packed (hncp) arrangements are synthesized by pulsed laser deposition (PLD) using polystyrene colloidal monolayers as templates and with subsequent annealing in air. The hncp‐array formation is governed by in situ volume shrinkage of amorphous TiO2 nanorods in the crystallizing process during annealing. The array periodicity can easily be tuned by different sphere sizes of the colloidal template, whereas the distance between neighboring nanorods can be controlled by altering the background gas pressure during the PLD process, at a given periodicity for the nanorod array. Parameter‐controlled growth is helpful for investigating and optimizing the parameter‐dependent field‐emission properties. The hncp nanorod array exhibits an enhanced field‐emission (FE) performance compared to both particle films and nanorod arrays with top aggregation. With an increase in periodicity of a hncp nanorod array, the field‐enhancement factor decreases and the turn‐on FE field increases. FE characteristics can be further enhanced by increasing the distance between adjacent nanorods while maintaining the same periodicity. The parameter‐optimized results suggest that the arrays with a smaller periodicity and a larger distance display the best FE performance and could be highly valuable for designing field‐emission devices based on these periodic nanorod arrays.
Materials for a Reliable Solid‐State Dye Laser at the Red Spectral Edge
Authors: Garcia‐Moreno Inmaculada , Costela Angel , Martin Virginia , Pintado‐Sierra Mercedes , Sastre Roberto
Published: July 2009

In the search to extend the tuning range of solid‐state dye lasers (SSDLs) to the red‐edge spectral region, new photosensitive materials have been designed and synthesized based on six commercial dyes (sulforhodamine B, perylene red, rhodamine 640, LDS698, LDS722, and LDS730) incorporated into different linear, crosslinked, fluorinated, and sililated polymeric matrices. Under transversal pumping at 532 nm, these materials exhibit highly efficient, stable, as well as wavelength‐tunable laser action from the visible‐to‐NIR spectral region (575–750 nm). The lasing performance of the materials doped with perylene and xanthene dyes is, to the best of our knowledge, the highest achieved to date for these chromophores when incorporated into organic, inorganic, or hybrid matrices. Regarding the LDS derivatives, this is the first time that laser action from these dyes in solid‐state media is reported. These particular characteristics have impelled the building of the first prototype SSDL that is compact, versatile, and easy to handle.
Printable Ferroelectric PVDF/PMMA Blend Films with Ultralow Roughness for Low Voltage Non‐Volatile Polymer Memory
Authors: Kang Seok Ju , Park Youn Jung , Bae Insung , Kim Kap Jin , Kim Ho‐Cheol , Bauer Siegfried , Thomas Edwin L. , Park Cheolmin
Published: July 2009

Here, a facile route to fabricate thin ferroelectric poly(vinylidene fluoride) (PVDF)/poly(methylmethacrylate) (PMMA) blend films with very low surface roughness based on spin‐coating and subsequent melt‐quenching is described. Amorphous PMMA in a blend film effectively retards the rapid crystallization of PVDF upon quenching, giving rise to a thin and flat ferroelectric film with nanometer scale β‐type PVDF crystals. The still, flat interfaces of the blend film with metal electrode and/or an organic semi‐conducting channel layer enable fabrication of a highly reliable ferroelectric capacitor and transistor memory unit operating at voltages as low as 15 V. For instance, with a TIPS‐pentacene single crystal as an active semi‐conducting layer, a flexible ferroelectric field effect transistor shows a clockwise I–V hysteresis with a drain current bistability of 103 and data retention time of more than 15 h at ±15 V gate voltage. Furthermore, the robust interfacial homogeneity of the ferroelectric film is highly beneficial for transfer printing in which arrays of metal/ferroelectric/metal micro‐capacitors are developed over a large area with well defined edge sharpness.
Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices
Authors: Mauro Matteo , Procopio Elsa Quartapelle , Sun Yinghui , Chien Chen‐Han , Donghi Daniela , Panigati Monica , Mercandelli Pierluigi , Mussini Patrizia , D'Alfonso Giuseppe , De Cola Luisa
Published: July 2009

A series of neutral, dinuclear, luminescent rhenium(I) complexes suitable for phosphorescent organic light emitting devices (OLEDs) is reported. These compounds, of general formula [Re2(µ‐Cl)2(CO)6(µ‐1,2‐diazine)], contain diazines bearing alkyl groups in one or in both the β positions. Their electrochemical and photophysical properties are presented, as well as a combined density functional and time‐dependent density functional study of their geometry, relative stability and electronic structure. The complexes show intense green/yellow emissions in toluene solution and in the solid state and some of the complexes possess high emission quantum yields (ϕ = 0.18–0.22 for the derivatives with disubstituted diazines). In butyronitrile glass, at 77 K, due to the charge transfer character of the lowest (emitting) excited state, strong blue shift of the emission is observed, accompanied by a strong increase in the lifetime values. The highest‐performing emitting complex, containing cyclopentapyridazine as ligand, is tested in a polymer‐based light‐emitting device, with poly(9‐vinylcarbazole) as matrix, as well as in a device obtained by vacuum sublimation of the complex in the 2,7‐bis(diphenylphosphine oxide)‐9‐(9‐phenylcarbazol‐3‐yl)‐9‐phenylfluorene (PCF) matrix. This represents the first example of devices obtained with a rhenium complex which can be sublimed and is solution processable. Furthermore, the emission is the bluest ever reported for electrogenerated luminescence for rhenium complexes.
Stimulation of the subthalamic nucleus and impulsivity: Release your horses
Authors: Ballanger Benedicte , van Eimeren Thilo , Moro Elena , Lozano Andres M. , Hamani Clement , Boulinguez Philippe , Pellecchia Giovanna , Houle Sylvain , Poon Yu Yan , Lang Anthony E. , Strafella Antonio P.
Published: July 2009

Objective

In Parkinson disease (PD) patients, deep brain stimulation (DBS) of the subthalamic nucleus (STN) may contribute to certain impulsive behavior during high‐conflict decisions. A neurocomputational model of the basal ganglia has recently been proposed that suggests this behavioral aspect may be related to the role played by the STN in relaying a “hold your horses” signal intended to allow more time to settle on the best option. The aim of the present study was 2‐fold: 1) to extend these observations by providing evidence that the STN may influence and prevent the execution of any response even during low‐conflict decisions; and 2) to identify the neural correlates of this effect.

Methods

We measured regional cerebral blood flow during a Go/NoGo and a control (Go) task to study the motor improvement and response inhibition deficits associated with STN‐DBS in patients with PD.

Results

Although it improved Unified Parkinson Disease Rating Scale motor ratings and induced a global decrease in reaction time during task performance, STN‐DBS impaired response inhibition, as revealed by an increase in commission errors in NoGo trials. These behavioral effects were accompanied by changes in synaptic activity consisting of a reduced activation in the cortical networks responsible for reactive and proactive response inhibition.

Interpretation

The present results suggest that although it improves motor functions in PD patients, modulation of STN hyperactivity with DBS may tend at the same time to favor the appearance of impulsive behavior by acting on the gating mechanism involved in response initiation. Ann Neurol 2009;66:817–824
Solvent‐free N‐nitrosation of secondary amines mediated by polymeric nitrosation reagent
Authors: Karimi Zarchi Mohammad Ali , Noei Jalil
Published: July 2009

A combination of cross‐linked poly(4‐vinylpridininium) chloride [P4‐H] Cl, [II], and sodium nitrite or quaternized cross‐linked poly(N‐methyl‐4‐vinylpyridinum) nitrite [P4‐Me] NO2, [IV], was used as effective nitrosating agents for the N‐nitrosation of secondary amines under solvent‐free conditions in high yields. The spent polymeric reagents can usually be removed quantitatively and regenerated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of polymer‐grafted natural rubbers by radical photopolymerization of vinyl monomers initiated from the rubber chains
Authors: Derouet D. , Tran Quang Ngoc , Thuc H. Ha
Published: July 2009

The synthesis of polymer‐grafted natural rubbers (NRs) was considered through photopolymerization of vinyl monomers initiated from N,N‐diethyldithiocarbamate groups previously introduced onto cis 1,4‐polyisoprene units of NR chains. The development of the procedure was made with methyl methacrylate (MMA) as monomer. First, initiation of MMA photopolymerization was tested using a model molecule of the N,N‐diethyldithiocarbamate‐functionalized 1,4‐polyisoprene unit to verify the feasibility of the procedure considered. Then, MMA polymerization was successfully initiated from N,N‐diethyldithiocarbamate‐functionalized NR backbone used as macroinitiator, and the conditions of grafting were optimized. It was shown that MMA grafting could occur either in monomer medium, in solution in toluene, and in latex medium, and that the quantities of homopolymer formed were still low. Thereafter, grafting studies were performed with other vinyl monomers (styrene, methacrylonitrile, acrylamide, acrylic acid) showing that grafting efficiency depends essentially on the nature of the monomer. The method developed here was shown particularly well adapted for the synthesis of polymer‐grafted NR with monomers of low polarity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Studies on epoxy/calcium carbonate nanocomposites
Authors: Jain Ritu , Narula A. K. , Choudhary Veena
Published: July 2009

The article describes the preparation of epoxy‐calcium carbonate nanocomposites using diaminodiphenyl sulfone (DDS) as a curing agent. The curing behavior of diglycidyl ether of bisphenol‐A (DGEBA) (1 mol) in the presence of varying amounts of nanocalcium carbonate was investigated by differential scanning calorimetry (DSC) using stoichiometric amounts of diaminodiphenyl sulphone (0.5 mol) as curing agent. The amount of calcium carbonate (∼ 44 nm) was varied from 2% to 10% (w/w). In the DSC scans of these samples, a broad exothermic transition due to curing was observed in the temperature range of 110–335°C. As expected, heat of curing decreased with increasing amount of nanocalcium carbonate; however it did not affect the curing characteristics, thereby indicating that the filler did not hinder the curing reaction. Thermal stability of DGEBA in the presence of varying amounts of nano‐CaCO3 after isothermal curing [(i.e., by heating in an air oven at 80°C (1 h), 100°C (1 h), 120°C (1.5 h), and 180°C (4 h)] was evaluated by thermogravimetry. All the samples were stable upto 350°C, and char yield at 800°C increased with increasing amount of nanocalcium carbonate. Rectangular bars were prepared by mixing DGEBA, DDS, and varying amounts of CaCO3 using silicone mold. The nanocomposites were characterized by X‐ray, scanning electron microscopy (morphological characterization), and dynamic mechanical analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Removal of paraquat pesticide from aqueous solutions using a novel adsorbent material based on polyacrylamide and methylcellulose hydrogels
Authors: Aouada Fauze A. , Pan Zhongli , Orts William J. , Mattoso Luiz H. C.
Published: July 2009

This research studied the characteristics of poly(acrylamide) and methylcellulose (PAAm‐MC) hydrogels as a novel adsorbent material for removal of pesticide paraquat, from aqueous solution, with potential applications in curbing environmental risk from such herbicides. PAAm‐MC hydrogels with different acrylamide (AAm) and MC concentrations were prepared by a free‐radical polymerization method. The capability of the hydrogels in removing paraquat dichloride from aqueous solution was determined using UV–Vis analysis. The scanning electron microscopy method was used to study the morphological properties of the hydrogels, and swelling degree (Q) of the hydrogels was also measured. The entrapped MC in PAAm chains provoked significant changes in morphological, hydrophilic, and adsorption properties of the PAAm‐MC hydrogels. The adsorption capacity of hydrogels was strongly influenced by AAm, MC, and paraquat concentrations with the highest adsorption capacity (qeq = 14.3 mg g−1) was observed for hydrogels synthesized with 6.0% AAm with 0.75% MC swollen in 45.7 mg L−1 of paraquat solution. Freundlich model performed better than Langmuir model in describing the adsorption isotherm of PAAm‐MC/paraquat system, implying a heterogeneous surface. These results suggest that PAAm‐MC hydrogels are potentially viable absorbents for removal of paraquat pesticide from aqueous solution and cleaning water contaminated with dyes, heavy metals, and others pesticides. © 2009 Wiley Periodicals, Inc. Journal of Appl Polym Sci, 2009
Mesomorphic behavior and optical properties of liquid‐crystalline polysiloxanes bearing different chiral groups
Authors: Meng Fan‐Bao , Zhang Bao‐Yan , Lian Jiao , Wu Yan‐Peng , Li Xi‐Zhi , Yao Dan‐Shu
Published: July 2009

A series of side‐chain liquid crystalline polysiloxanes bearing different chiral groups were synthesized with a cholesteric liquid crystalline monomer cholesteryl 2‐(4‐allyloxy‐benzoxy)‐succinate and a chiral monomer 2‐isopropyl‐5‐methyl‐cyclohexyl 4‐allyloxy‐benzoate. All the chiral polymers showed cholesteric mesophase with very wide mesophase temperature ranges. Along with phase morphology varied from solid state to isotropic state, the sample exhibited varied spectroscopic images, indicating different phase behaviors between mesophase and isotropic state. Optical properties of the polymers were characterized with circular polarization spectra and optical rotation analysis. The specific rotations of the chiral liquid crystalline polymers were all negative values and increased with increase of menthyl component in the polymer systems. As compared with corresponding monomers, the polymers showed significantly lower specific rotations, suggesting that the existence of polysiloxane main chains affect the molecule polarity. The selective light reflection maximum wavelength of the polymers at the same temperature shifted to short wavelength with decrease of cholesteryl component, indicating that the helical pitch becomes shorter due to induction of menthyl groups with high chiral properties. The temperature dependence of selective light reflection maximum wavelength was shifted to a longer wavelength region as the temperature decreased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Removal of heavy‐metal ions by magnetic beads containing triazole chelating groups
Authors: Uzun Lokman , Kara Ali , Osman Bilgen , Yılmaz Erkut , Beşirli Necati , Denizli Adil
Published: July 2009

The aim of this study was to prepare magnetic beads that could be used for the removal of heavy‐metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [m‐poly(EGDMA–VTAZ)] beads were produced by suspension polymerization in the presence of a magnetite Fe3O4 nanopowder. The specific surface area of the m‐poly(EGDMA–VTAZ) beads was 74.8 m2/g with a diameter range of 150–200 μm, and the swelling ratio was 84%. The average Fe3O4 content of the resulting m‐poly(EGDMA–VTAZ) beads was 14.8%. The maximum binding capacities of the m‐poly(EGDMA–VTAZ) beads from aquous solution were 284.3 mg/g for Hg2+, 193.8 mg/g for Pb2+, 151.5 mg/g for Cu2+, 128.1 mg/g for Cd2+, and 99.4 mg/g for Zn2+. The affinity order on a mass basis was Hg2+ > Pb2+ > Cu2+ > Cd2+> Zn2+. The binding capacities from synthetic waste water were 178.1 mg/g for Hg2+, 132.4 mg/g for Pb2+, 83.5 mg/g for Cu2+, 54.1 mg/g for Cd2+, and 32.4 mg/g for Zn2+. The magnetic beads could be regenerated (up to ca. 97%) by a treatment with 0.1M HNO3. These features make m‐poly(EGDMA–VTAZ) beads potential supports for heavy‐metal removal under a magnetic field. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Investigation of the structural, thermal, mechanical, and optical properties of poly(methyl methacrylate) and poly(vinylidene fluoride) blends
Authors: Pawde S. M. , Deshmukh Kalim
Published: July 2009

In this investigation, poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride) (PVDF) blends (w/w) were prepared in a Brabender (South Hackensack, NJ) plasticorder with a thermoplastic mixing chamber (type W60) preheated at 180°C. These blends were further converted into films by a conventional solution casting method and characterized with Fourier transform infrared spectroscopy, differential scanning calorimetry, X‐ray diffraction, mechanical property measurements, impact strength testing, ultraviolet–visible spectroscopy, refractive‐index measurements, and contact‐angle study. The Fourier transform infrared results indicated that the compatibility between these two systems resulted from hydrogen bonding between the carbonyl group of PMMA and the CH2 group of PVDF. The thermal analysis showed depressions in the glass‐transition temperature, melting temperature, and crystallization temperature. The heat of crystallization increased with an increase in the PVDF content in the blend. An increase in the heat of crystallization meant an increase in the crystallinity. An increase in the cooling rate increased the crystallization rate. The improvement in the mechanical properties of the blend films indicated that the observed behavior was ascribable to a more coherent structure of the blends due to strong specific interactions between PMMA and PVDF chains. The impact strength analysis revealed a substantial increase in the impact strength from 21.64 to 38.52 J/m. Optical absorption spectra suggested the presence of an optical band gap energy that increased with an increase in the PVDF content in the blend. The contact angle against water increased with the PVDF content in the blend film, and this was caused by the hydrophobicity of PVDF due to the CF2 group of PVDF. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Development of polyurethanes with azo‐type chromophores for second‐order nonlinear optical applications
Authors: Tambe S. M. , Tasaganva R. G. , Jogul J. J. , Castiglione D. C. , Kariduraganavar M. Y.
Published: July 2009

Active nonlinear optical nitro‐substituted thiazole, benzothiazole, and thiadiazole chromophores were prepared and condensed with tolylene‐2,4‐diisocyanate (TDI) and 4,4′‐methylenedi(phenyl isocyanate) (MDI) to yield a series of polyurethanes. The resulting polyurethanes were characterized with Fourier transform infrared, proton nuclear magnetic resonance, and ultraviolet–visible spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. The weight‐average molecular weights of the polyurethanes ranged between 19,500 and 28,000 (weight‐average molecular weight/number‐average molecular weight = 1.71–2.15). All the polyurethanes exhibited excellent solubility in most common organic solvents, and this indicated that these polyurethanes offered good processability. The glass‐transition temperatures (Tg's) of the polyurethanes were in the range of 166–204°C. Among the polyurethanes, chromophores containing the nitrothiazole moiety exhibited lower Tg values in comparison with those of chromophores containing nitrobenzothiazole and nitrothiadiazole moieties. This was attributed to the small size of the nitrothiazole moiety in the polyurethane matrix. The polyurethanes containing a TDI backbone demonstrated relatively high Tg values in comparison with those of the polyurethanes containing an MDI backbone. This was a result of an enhancement of the rigidity caused by the incorporation of a toluene ring into the polyurethane backbone. The second harmonic generation (SHG) coefficients of the poled polyurethane films ranged from 67.29 to 105.45 pm/V at 1064 nm. High thermal endurance of the poled dipoles was observed for all the polyurethanes. This was attributed to the formation of extensive hydrogen bonds between urethane linkages. Furthermore, none of the developed polyurethanes showed SHG decay below 150°C, and this signified their acceptability for nonlinear optical devices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of montmorillonite treatment and montmorillonite dispersion state on the crystallization behavior of poly(ethylene terephthalate)/montmorillonite nanocomposites
Authors: Yin Ming , Li Chuncheng , Guan Guohu , Zhang Dong , Xiao Yaonan
Published: July 2009

TiO2/SiO2 sol was intercalated into montmorillonite (MMT), which was pretreated with polyvinylpyrrolidone (PVP). A series of poly(ethylene terephthalate) (PET)/MMT hybrids were prepared using the obtained MMT as polycondensation catalysts. X‐ray diffraction (XRD) results proved that MMT dispersion states could be controlled by the amount of TiO2/SiO2 sol that was incorporated into MMT, ranging from agglomeration to exfoliation. The crystallization behavior of PET/MMT composites synthesized in this study was characterized by differential scanning calorimeter (DSC), polarized optical microscope (POM) and scanning electron microscopy (SEM) to clarify the effects of clay treatment and its dispersion state on the crystallization behavior of the PET substrate. The results indicated that MMT treated with less PVP would retain relatively higher nucleation efficiency while when MMT containing more PVP, the nucleation effect of MMT became weaker. If MMT formed big grains within PET substrate, the disturbance of the growing crystals was negligible; but the exfoliation of MMT layers would greatly magnify the spatial constraint which would slow down the crystallization process of PET matrix. For certain exfoliated PET/MMT composites, the crystallization rate was even lower than that of pure PET though clay content was low. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of doping anions on the ion exchange behavior of polypyrrole
Authors: Li Sheng , Qiu Yubing , Guo Xingpeng
Published: July 2009

The ion exchange behavior of polypyrrole (PPy) doped with a variety of dopants (A), namely chloride, nitrate, para‐toluene sulfonate (pTS−), and dodecyl sulfonate (DS−), was investigated by means of cyclic voltammetry (CV) in NaCl, NapTS, and AlCl3 aqueous solutions. The results show that PPy/pTS and PPy/DS films had the best anion and cation exchange ability, respectively. However, the ion exchange ability evaluated by CV charge cannot describe the exact amount of exchanged ions. For that reason, a new ion exchange experiment was designed to evaluate the amount of ions removed from NaCl aqueous solution to AlCl3 or NapTS aqueous solution. In addition, the ion exchange ratio is defined as the ratio of the charge associated with ion ejection to the synthesis charge, and can be conveniently converted to operating exchange capability (OEC). The ion exchange ratio and OEC can be used to characterize and evaluate the ion exchange ability of PPy/A films in different conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The effect of coupling agent on the microwave properties of the melt‐spun iron/earth nanocomposites
Authors: Guozhi Xie , Ping Wang , Liukui Yuan , Baoshan Zhang , Pinghua Lin , Huaixian Lu
Published: July 2009

The effects of silane coupling agent doping on the microstructure and microwave properties of melt‐spun Nd‐Fe‐Co alloys were investigated. All as‐milled powders, with or without silane coupling agent treatment, were characterized as flake‐like shape. However, it is found that with the addition of 0.25 mL coupling agent, the as‐milled Nd‐Fe‐Co powders can deagglomerate and become more uniform dispersion with smaller thickness. In contrast, the excessive addition of coupling agent led to somewhat higher thickness of the flakes and much more amount of coupling agent on the surface of powder. The electromagnetic properties show that the Reflection loss will arrive −27.1 dB at 4.2 GHz, for the addition of 0.25 mL coupling agent powders. The probably reasons for this are discussed on the basis of the morphology of the powders, uniform dispersion and the physical coating between the polymer and coupling agent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of membranes of poly(vinyl ether)s and their gas permeability
Authors: Sakaguchi Toshikazu , Koide Yohei , Hashimoto Tamotsu
Published: July 2009

Cationic polymerizations of various vinyl ethers with cyclic substituents were performed with BF3OEt2. The polymers had relatively high molecular weight (Mn: 18,900–132,000), although the polymerization of phenyl vinyl ether did not proceed. According to differential scanning calorimetry, the obtained poly(vinyl ether)s showed higher glass transition temperatures than room temperature. These poly(vinyl ether)s gave free‐standing membranes both by a solution‐casting method and by a hot‐press method. In the membranes prepared by solution‐casting, the oxygen permeability coefficients of these membranes were in the range of 0.81–6.01 barrers, and poly(2‐adamanthyl vinyl ether) showed the highest gas permeability among them. Gas permeability of the membranes prepared by hot‐press was lower than that of the membranes prepared by solution‐casting. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Platinum Films with Controlled 3‐Dimensional Nanoscopic Morphologies and Their Effects on Surface Enhanced Raman Scattering
Authors: Lee Hyun‐Ju , Lee U‐Hwang , Park Jin‐Young , Yoo Sang‐Hoon , Park Sungho , Kwon Young‐Uk
Published: July 2009

The synthesis of Pt thin films with a controlled nanoscopic architecture that can support surface enhanced Raman scattering (SERS) is reported. The syntheses are achieved by replicating the pores of a type of mesoporous silica thin film whose pore structure could be described as a regular array of vertical channels of ∼9 nm in diameter and their interconnections, forming a 3‐dimensional pore network. Electrochemical deposition into the pores followed by the removal of the templates produced Pt films composed of arrays of vertically standing Pt nanorods with narrow gaps between them. The 3‐dimensional nanostructure increases the surface area and enables the Pt film to absorb visible light. SERS studies of rhodamine 6G and benzenethiol on such Pt films as substrates reveals that the control of the nanostructure is critical for the SERS effect.
Characterization of electrochemical activity of a strain ISO2‐3 phylogenetically related to Aeromonas sp. isolated from a glucose‐fed microbial fuel cell
Authors: Chung Kyungmi , Okabe Satoshi
Published: July 2009

The microbial communities associated with electrodes in closed and open circuit microbial fuel cells (MFCs) fed with glucose were analyzed by 16S rRNA approach and compared. The comparison revealed that bacteria affiliated with the Aeromonas sp. within the Gammaproteobacteria constituted the major population in the closed circuit MFC (harvesting electricity) and considered to play important roles in current generation. We, therefore, attempted to isolate the dominant bacteria from the anode biofilm, successfully isolated a Fe (III)‐reducing bacterium phylogenetically related to Aeromonas sp. and designated as strain ISO2‐3. The isolated strain ISO2‐3 could grow and concomitantly produce current (max. 0.24 A/m2) via oxidation of glucose or hydrogen with an electrode serving as the sole electron acceptor. The strain could ferment glucose, but generate less electrical current. Cyclic voltammetry supported the strain ISO2‐3 was electrically active and likely to transfer electrons to the electrode though membrane‐associated compounds (most likely c‐type cytochrome). This mechanism requires intimate contact with the anode surface. Scanning electron microscopy revealed that the strain ISO2‐3 developed multiplayer biofilms on the anode surface and also produced anchor‐like filamentous appendages (most likely pili) that may promote long‐range electron transport across the thick biofilm. Biotechnol. Bioeng. 2009; 104: 901–910. © 2009 Wiley Periodicals, Inc.
Expression of merA, trxA, amoA, and hao in continuously cultured Nitrosomonas europaea cells exposed to cadmium sulfate additions
Authors: Radniecki Tyler S. , Semprini Lewis , Dolan Mark E.
Published: July 2009

The effects of CdSO4 additions on the gene expressions of a mercury reductase, merA, an oxidative stress protein, trxA, the ammonia‐monooxygenase enzyme (AMO), amoA, and the hydroxylamine oxidoreductase enzyme (HAO), hao, were examined in continuously cultured N. europaea cells. The reactor was fed 50 mM NH4+ and was operated for 78 days with a 6.9 days hydraulic retention time. Over this period, six successive batch additions of CdSO4 were made with increasing maximum concentrations ranging from 1 to 60 µM Cd2+. The expression of merA was highly correlated with the level of Cd2+ within the reactor (Rs = 0.90) with significant up‐regulation measured at non‐inhibitory Cd2+ concentrations. Cd2+ appears to target AMO specifically at lower concentrations and caused oxidative stress at higher concentrations, as indicated by the SOURs (specific oxygen uptake rates) and the up‐regulation of trxA. Since Cd2+ inhibition is irreversible and amoA was up‐regulated in response to Cd2+ inhibition, it is hypothesized that de novo synthesis of the AMO enzyme occurred and was responsible for the observed recovery in activity. Continuously cultured N. europaea cells were more resistant to Cd2+ inhibition than previously examined batch cultured cells due to the presence of Mg2+ and Ca2+ in the growth media, suggesting that Cd2+ enters the cell through Mg2+ and Ca2+ import channels. The up‐regulation of merA during exposure to non‐inhibitory Cd2+ levels indicates that merA is an excellent early warning signal for Cd2+ inhibition. Biotechnol. Bioeng. 2009; 104: 1004–1011. © 2009 Wiley Periodicals, Inc.