bluuebunny/crossref_metadata_2025 huggingface dataset:
FAK phosphorylation at Ser‐843 inhibits Tyr‐397 phosphorylation, cell spreading and migration
Authors: Jacamo Rodrigo , Jiang Xiaohua , Lunn J. Adrian , Rozengurt Enrique
Published: November 2006

Multiple stimuli promote the tyrosine phosphorylation and activation of focal adhesion kinase (FAK), which ultimately facilitates migration. Little is known about the effect of adhesion‐dependent signals and cytoskeleton organization on the regulation of FAK phosphorylation at serine sites, or about the role of FAK serine phosphorylation in cell migration. Here, we show that FAK phosphorylation at Ser‐843 is strikingly increased when adherent cells are removed from the substratum and held in suspension or by treatment of adherent cells with cytochalasin D, conditions that disrupt the F‐actin cytoskeleton and promote focal adhesion disassembly. Notably, the increase in Ser‐843 phosphorylation was accompanied by a concomitant sharp decrease in Tyr‐397 phosphorylation. To further examine the cause‐effect relationship between these two phosphorylation sites we generated Ser‐843 phosphorylation‐deficient and phosphorylation‐mimicking FAK mutants. We found that mutation of Ser‐843 to aspartic acid (FAK[S843D]) markedly decreased FAK Tyr‐397 phosphorylation in integrin‐stimulated cells. While the migratory defect of FAK‐deficient fibroblasts was rescued by stable re‐expression of WT FAK or FAK[S843A], stable re‐expression of FAK[S843D] failed to restore the ability of the cells to migrate into the denuded area of a wound. Our results indicate that increased FAK phosphorylation at Ser‐843 represses FAK phosphorylation at Tyr‐397, thus suggesting a mechanism of cross‐talk between these phosphorylation sites that could regulate FAK‐mediated cell shape and migration. J. Cell. Physiol. 210: 436–444, 2007. © 2006 Wiley‐Liss, Inc.
Establishment of histone gene regulation and cell cycle checkpoint control in human embryonic stem cells
Authors: Becker Klaus A. , Stein Janet L. , Lian Jane B. , van Wijnen Andre J. , Stein Gary S.
Published: November 2006

Rapid self‐renewal of human embryonic stem (ES) cells (NIH designation WA01 and WA09) is accommodated by an abbreviated cell cycle due to a reduction in the G1 phase. Thus, molecular mechanisms operative in ES cells may expedite the cellular commitment to progress into S phase to initiate replication of DNA and biosynthesis of histone proteins to form new chromatin. Here we show that the selective cell cycle regulated expression of individual histone H4 gene copies, which is typical for somatic cell types, is already firmly established in human ES cells. This early establishment of H4 gene regulation, which is E2F independent, is consistent with co‐expression of the cognate transcriptional regulators HiNF‐P and p220NPAT. Human ES cells differ from somatic cells in the expression of members of the E2F family and RB‐related pocket proteins (p105RB1, p107RBL1, and p130RBL2/RB2) that control expression of genes encoding enzymes for nucleotide metabolism and DNA synthesis. Human ES cells rapidly and robustly (>200‐fold) induce the cyclin dependent kinase (CDK) inhibitor p21WAF1/CIP1 upon gamma‐irradiation. This DNA damage response promptly reduces histone gene expression as well as mRNA levels for HiNF‐P and p220NPAT and causes accumulation of unprocessed histone H4 precursor RNAs. Furthermore, while E2F4, E2F5 and p130RBL2/RB2 are the major E2F and pocket protein mRNAs in actively proliferating ES cells, expression levels of E2F5, E2F6, and p105RB1 are most strongly elevated during cell cycle arrest in cells responding to DNA damage. Our data suggest that the brief G1 phase of ES cells is supported by a potent p21WAF1/CIP1 related DNA damage response that functions through several mechanisms to rapidly inhibit cell cycle progression. This response may alter the E2F/pocket protein combinations that control E2F dependent genes and block H4 gene expression by inhibiting histone‐specific transcription factors and processing of histone gene transcripts, as well as by destabilizing histone mRNAs. J. Cell. Physiol. 210: 517–526, 2007. © 2006 Wiley‐Liss, Inc.
Detection of antigen‐specific T cells on p/MHC microarrays
Authors: Deviren Gokhan , Gupta Kapil , Paulaitis Michael E. , Schneck Jonathan P.
Published: November 2006

The development of high‐throughput protein microarrays for rapidly determining antigen‐specific T‐cell receptor repertoires of diverse T‐cell populations can enable comprehensive, broad‐based analyses of T‐cell responses. Promising applications include medical diagnostics, vaccine development, treatment of autoimmune diseases and detection of potential agents of bioterrorism. In this study, we examined the feasibility of using peptide/major histocompatibility complex (p/MHC) microarrays to selectively capture and enumerate antigen‐specific T cells. Results are presented for p/MHC microarrays consisting of a dimeric MHC‐immunoglobulin complex, Kb‐Ig, loaded with either a cognate or non‐cognate peptide for binding CD8+ T cells. We quantified the sensitivity of these Kb‐Ig microarrays by measuring a lower detection limit of 0.05% antigen‐specific CD8+ T cells mixed with splenocytes from C57BL/6J mouse. A fivefold increase in this lower detection limit (0.01%) was achieved using a secondary capture anti‐Ig antibody to coat the microarray surface. This higher sensitivity is comparable to that obtained using standard state‐of‐the‐art fluorescence activated cell sorting (FACS) instruments. We also found that contacting the T‐cell suspension with the Kb‐Ig microarrays under mild shear flow conditions produced more uniform distributions of captured T cells on the individual spots and better spot‐to‐spot reproducibility across the entire microarray. Copyright © 2006 John Wiley & Sons, Ltd.
Measurement of DTI metrics in hemorrhagic brain lesions: Possible implication in MRI interpretation
Authors: Haris Mohammad , Gupta Rakesh K , Husain Nuzhat , Hasan Khader M , Husain Mazhar , Narayana Ponnada A
Published: November 2006

Purpose

To understand the biological basis of possible mechanisms responsible for increased fractional anisotropy (FA) in different stages of hemorrhage and hemorrhagic brain lesions.

Materials and Methods

A total of 19 patients with cerebral hemorrhage (CH), five patients with hemorrhagic infarct (HI), and nine patients with hemorrhagic brain tumor (HBT) were prospectively evaluated with diffusion tensor imaging (DTI) and the FA and mean diffusivity (MD) was quantified. Ex vivo DTI of blood clot and histology of the blood clot and HBT were performed to interpret the temporal changes in the DTI metrics.

Results

High FA (>0.20) with low MD in the acute and early subacute stage and low FA (<0.20) with increased MD in the late subacute and chronic stage of CH and HI were observed. HBT showed high FA with low MD at all stages. In CH and HI, a significant reduction in FA (P < 0.001) with increased MD (P < 0.001) was seen in the late subacute and chronic stages compared to the acute and early subacute stages, normal white matter (NWM), and HBT. In HBT, there was no significant statistical difference in the FA values between different stages. Histology of HBT and ex vivo blood clot showed structural organization of intact red blood cells (RBCs) with fibrin mesh where the FA values were high compared to normal tissue region that is devoid of blood.

Conclusion

Intact RBCs entangled within fibrin mesh appear to be responsible for high FA in hemorrhagic brain lesions. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
In vivo perfusion, T1, and T2 measurements in the female pelvis during the normal menstrual cycle: A feasibility study
Authors: Hoad Caroline L. , Fulford Jonathan , Raine‐Fenning Nick J. , Campbell Bruce K. , Johnson Ian R. , Gowland Penelope A.
Published: November 2006

Purpose

To quantify T1, T2, and regional tissue perfusion in uterine tissues, with MR imaging in clinically feasible imaging times, using echo planar imaging (EPI) techniques over a single menstrual cycle.

Materials and Methods

A total of 24 healthy ovulating women were scanned; however, complete data sets through the menstrual cycle were not obtained from all women. Three scans were performed to coincide prospectively with the follicular, periovulatory, and luteal phases of the cycle. T1 and perfusion were measured simultaneously using flow alternating inversion recovery (FAIR), while T2 was measured using a single Hahn spin‐echo (SE) EPI sequence.

Results

Between the follicular and periovulatory phases, statistically significant increases (P < 0.05) were seen for the T2 of the endometrium and perfusion of the myometrium as well as the T2/T1 ratio for both endometrium and myometrium. A statistically significant decrease was seen in the endometrial T2 between the periovulatory and luteal phases of the cycle. Tissue differentiation was achieved using the parameters measured, with T1 and T2 being statistically greater for the endometrium than for the myometrium, and endometrial perfusion being statistically lower than myometrial perfusion.

Conclusion

These results show the feasibility of using these techniques to measure T1, T2, and perfusion in uterine tissues and of extending this work to study pathological conditions. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Fragmentation induced in atmospheric pressure photoionization of peptides
Authors: Debois D. , Giuliani A. , Laprévote O.
Published: November 2006

In this work, the fragmentation of peptides under atmospheric pressure photoionization conditions is investigated. Intensive fragmentations into b/y‐ and c‐sequence ions are reported. Abundance of these c‐ions appeared to be related to the quantity of dopant infused and to the disappearance of the doubly protonated peptide ion. A careful analysis of the role of the dopant indicates that the fragmentations are not dependent on the nature of the dopant but on their ionization efficiencies. This result shows that the fragmentation arises from the reaction of the protonated peptide with photoelectrons released upon ionization of the dopant in an electron capture dissociation/electron transfer dissociation (ECD/ETD) type mechanism. Experiments with peptides bearing a single proton indicate that additional mechanisms are involved. H‐atom transfer reactions are suggested to be responsible for the fragmentations as well. Those atoms could arise either from the dopant ions or from negatively charged solvent nanodroplets. This is the first report of an ECD/ETD mechanism in a dense medium and at atmospheric pressure. Copyright © 2006 John Wiley & Sons, Ltd.
The effects of pulse energy variations on the dimensions of microscopic thermal treatment zones in nonablative fractional resurfacing
Authors: Bedi Vikramaditya P. , Chan Kin Foong , Sink R. Kehl , Hantash Basil M. , Herron G. Scott , Rahman Zakia , Struck Steven K. , Zachary Christopher B.
Published: November 2006

Background and Objectives

We examined the effects of pulse energy variations on the dimensions of microscopic thermal injury zones (MTZs) created on human skin ex vivo and in vivo using nonablative fractional resurfacing.

Materials and Methods

A Fraxel® SR laser system emitting at 1,550 nm provided an array of microscopic spots at variable densities. Pulse energies ranging from 4.5 to 40mJ were tested on human abdominal skin ex vivo and in vivo. Tissue sections were stained with hematoxylin and eosin (H&E) or nitro blue tetrazolium chloride (NBTC) and MTZ dimensions were determined. Ex vivo and in vivo results were compared. Dosimetry analyses were made for the surface treatment coverage calculation as a function of pulse energy and collagen coagulation based on H&E stain or cell necrotic zone based on NBTC stain.

Results

Each MTZ was identified by histological detection of a distinct region of loss of tissue birefringence and hyalinization, representing collagen denaturation and cell necrosis within the irradiated field immediately, 1, 3, and 7days after treatment. At high pulse energies, the MTZ depth could exceed 1 mm and width approached 200 µm as assessed by H&E. NBTC staining revealed viable interlesional tissue. In general, no statistically significant difference was found between in vivo and ex vivo depth and width measurements.

Conclusions

The Fraxel® SR laser system delivers pulses across a wide range of density and energy levels. We determined that increases in pulse energy led to increases in MTZ depth and width without compromising the structure or viability of interlesional tissue. Lasers Surg. Med. 39:157–163, 2007. © 2007 Wiley‐Liss, Inc.
Detection of sentinel nodes by a novel red‐fluorescent dye, ATX‐S10Na (II), in an orthotopic xenograft rat model of human gastric carcinoma
Authors: Koyama Tomoki , Tsubota Akihito , Nariai Koichi , Yoshikawa Tetsuya , Mitsunaga Makoto , Sumi Makoto , Nimura Hiroshi , Yanaga Katsuhiko , Yumoto Yoko , Mabashi Yasuo , Takahashi Hiroshi
Published: November 2006

Background and Objective

We developed a new imaging system to detect sentinel nodes (SNs) using a novel fluorescent tracer, ATX‐S10Na(II), and investigated its usefulness in an animal model.

Study Design/Materials and Methods

Human gastric carcinoma cells were implanted orthotopically into nude rats. ATX‐S10Na(II) was injected subserosally into the primary tumor lesion, and visualized by a fluorescence spectro‐laparoscope. Presence of tumor cells in lymph nodes (LNs) was determined by RT‐PCR specific for human β‐actin.

Results

Injection of ATX‐S10Na(II) was successful in 27 tumor‐bearing rats. A red fluorescence was incorporated into the left gastric and hepatic LNs in 25 and 2 rats, respectively. Of note, human β‐actin was detected in most of these LNs. Fluorescence was not detected in LNs that did not contain cancer.

Conclusion

ATX‐S10Na(II) is useful for the detection of cancer‐containing SNs in an animal model of gastric carcinoma, and may serve as a novel tracer in SN navigation surgery. Lasers Surg. Med. © 2006 Wiley‐Liss, Inc.
Biaxial Orientation in Triple Centrifuged Natural Rubber
Authors: Alam Mohammad Mahay , Asano Tsutomu
Published: November 2006

Natural rubber (NR) latex was purified through triple centrifugation process and film samples were prepared. The strain‐induced crystallization was studied during the uniaxial elongation of the NR samples at room temperature. Crystalline orientation was detected by wide angle x‐ray diffraction (WAXD) measuring the intensity of 200 and 120 reflections. The WAXD patterns were compared with the aspect ratio (width/length) of the original NR films. The results indicate that the induced crystals have a biaxial orientation (BO), where the c‐axis is parallel to the draw direction and the a‐axis is parallel to the film surface. Using the WAXD through patterns, we distinguish the highly oriented BO region in the samples. In order to analyze the structure and properties of the NR, the effect of BO is an essential factor.
Application and Modification of Cyclometalated Ruthenium(II) Complex [Ru(o‐C6H4‐2‐C5H4N)‐ (MeCN)4]PF6 for Atom Transfer Radical Polymerization
Authors: Camacho Francisco Diaz , Morales Salvador Lopez , Le Lagadec Ronan , Alexandrova Larissa
Published: November 2006

Polymerizations of n‐butyl acrylate (BA), methyl methacrylate (MMA) and styrene (St) were promoted by the Ru(II) cyclometalated complex with labile MeCN ligand in the presence of Al(OiPr)3. The polymerization proceeds via radical mechanism and requires the loss of MeCN ligand. The poor control over the polymerizations can be explained in terms of the traditional ATRP scheme. However, the controllability may be significantly improved by addition of reducing SnCl2. Mechanism of the process is proposed.
Synthesis and Electrorheological Characterization of Polyaniline/Barium Titanate Hybrid Suspension
Authors: Fang Fei Fei , Kim Ji Hye , Choi Hyoung Jin
Published: November 2006

As organic/inorganic composites having attracted much attention due to their heterogeneous physical properties, conducting polyaniline (PANI) and barium titanate (BaTiO3) which possesses large electronic resistance and excellent dielectric strength, were utilized to synthesize PANI/BaTiO3 hybrid which is applicable for an electrorheological (ER) material via ‘in‐situ’ oxidative polymerization. Physical properties of the obtained PANI/BaTiO3 composites were characterized via Fourier‐transform infrared spectra (FT‐IR), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). The ER behaviors were investigated via a rotational rheometer, and their shear stresses were fitted using our previously proposed rheological equation of state.
Reinforcement of Biodegradable Poly(DL‐lactic acid) Material by Equal‐Channel Angular Extrusion
Authors: Cui Hongxiang , Zhang Lianhong , Gong Jianguo , Ma Yuchun , Ying Wang
Published: November 2006

The purpose of this study was to reinforce biodegradable poly(DL‐lactic acid) (PDLLA) material using a new method, equal‐channel angular extrusion (ECAE). Different processing parameters, including the number of extrusion passes and the process temperature, were investigated to analyze their effect on the PDLLA properties. Experimental results indicate that the mechanical strength of PDLLA increased with the number of extrusion passes. The extrusion temperature also affected the mechanical strength of the PDLLA. After two ECAE passes, the bending strength of PDLLA increased from 83.3 to 178.7 MPa. The bending fracture mode for PDLLA changed from brittle failure for initial specimens to ductile fracture after ECAE processing. SEM micrographs showed that the longitudinal split surfaces of PDLLA are of a fibrillar structure. Taken together, the results suggest that ECAE might represent a useful approach for the preparation of reinforced PDLLA.
A “ladder” Morphology in an ABC Triblock Copolymer
Authors: Kaneko Takeshi , Suda Kazuya , Satoh Kotaro , Kamigaito Masami , Kato Toshinori , Ono Tomohiro , Nakamura Eiji , Nishi Toshio , Jinnai Hiroshi
Published: November 2006

ABC triblock copolymers are known to exhibit a wide variety of unique types of morphologies compared to AB diblock copolymers. In the present study, poly(styrene‐block‐(ethylene‐alt‐propylene)‐block‐(methyl methacrylate)) (SEPM) triblock copolymers were synthesized and their morphologies were extensively studied by transmission electron microtomography (TEMT). In the SEPM triblock copolymer, two kinds of morphologies coexist: One was the well‐known knitting morphology, and the other was a novel morphology called the “ladder morphology”. The ladder morphology was a major morphology in the SEPM copolymer, the stability of which was discussed in terms of the interfacial area and the solubility parameters between the three components.
Magnetic Alignment of Rhodamine B Intercalated in Synthetic Mica
Authors: Kimura Tsunehisa , Uemura Taichi , Kimura Takumasa , Takagi Shinsuke , Inoue Haruo
Published: November 2006

Rhodamine B was intercalated in interlayer spaces of Somasif Me‐100, a synthetic mica, and the obtained rhodamine B/Somasif hybrid was suspended in a UV‐curable resin precursor. Then, the suspension was subjected to an applied rotating magnetic field to align the hybrid particles, followed by solidification of the medium by UV irradiation to fix the alignment. The hybrid particles were aligned so that the Somasif layer lay perpendicular to the axis of rotation of the applied rotating magnetic field. UV/vis measurement indicated that the transition moment of xanthene ring of rhodamine B lay inclined to the layer of Somasif.
Study of the Impact Resistance of Physically and Dynamically Vulcanized Mixtures of PP/EPDM
Authors: Murillo Edwin A. , López Betty L.
Published: November 2006

Physically and dynamically vulcanized (TPV) mixtures of polypropylene (PP) and ethylene propylene diene terpolymer (EPDM) are prepared by extrusion in order to improve the impact resistance of PP. To enhance the chemical compatibility and provide better interaction between the PP and EPDM in the physical mixtures, both polymers are modified with maleic anhydride (MAH) in solution using xylene as solvent and dicumyl peroxide (DCP) as initiator. The qualitative and quantitative determination of the degree of grafting is study by Fourier Transform Infrared Spectroscopy (FTIR) and varying the amount of DCP and/or amount of MAH in order to determine the optimum amounts to obtain the highest degree of grafting. The effect of the relation of PP/EPDM, the amount of reinforcement filler and mix rate are studied for modified polymer mixtures (PP‐g‐MAH/EPDM‐g‐MAH). For the TPV of PP/EPDM the effects of amount and triallylisocyanurate (TAC) as coupling agent in presence of different amounts of DCP are studied. The physical mixtures of modified polymers prepared with a PP/EPDM ratio of 80/20 and the TPVs blends prepared with a PP/EPDM ratio of 70/30 and containing 15% filler at 60 rpm show the highest impact resistance. The impact resistance, melt flow index and hardness of the different mixtures are measured to determine their possible applications to prepare front panels and bumpers for automobiles by injection molding.
Pre‐Averaged Sampling On the Entanglement Kinetics for Polymer Dynamics
Authors: Horio Kazushi , Masubuchi Yuichi
Published: November 2006

A new model for entangled polymer dynamics based on pre‐averaged sampling of the entanglement structure is proposed. Although it has been reported that sliplink simulations are powerful and promising to predict entangled polymer dynamics, it is still unpractical to calculate polymers with many entanglements. In the present study, a possible approach to achieve fast calculation is proposed by pre‐averaged sampling of entanglement structure with skipping detail kinetics of entanglements dominated by chain ends in conventional sliplink models. To achieve time development of the chain conformation and entanglement structure, i) number of entanglement per chain and number of monomers for each segment are randomly obtained from the equilibrium distribution proposed by Schieber [J. Chem. Phys. 2003, 118, 5162] and ii) the renewed entanglement structure is mechanically equilibrated. The established power‐laws on molecular weight dependence of chain dimension, the longest relaxation time and self‐diffusion coefficient were reasonably reproduced. Comparison on linear viscoelastic response is also discussed.
Characterization of PVA and Chitosan/PVA Blends Prepared from Aqueous Solutions of Various Na2SO4 Concentrations
Authors: Drambei Petronela , Nakano Yumiko , Bin Yuezhen , Okuno Tsumuko , Matsuo Masaru
Published: November 2006

Uniplaner orientation of a particular crystal plane along the surface of a film was investigated for poly (vinyl alcohol) (PVA) film prepared by a coagulation bath with concentrated aqueous solution containing 100 ∼ 300g of Na2SO4 against 1 ℓ of water. The orientation distribution functions of the three crystallographic principal axes of the dried films were obtained by the X‐ray diffraction technique. The same treatment was carried out for the films prepared by stretching biaxially of the fresh gel and then by drying the resultant fresh gel. The very high preferential orientation of the crystal chain axes and amorphous chain segments could be realized by the biaxially elongation. Accordingly, the techniques were applied to the biaxially stretching of chitosan and PVA blend films with high Young's modulus. The planer orientation of the chain axes of chitosan and PVA crystallites could be confirmed. The morphology of the film surface was estimated by measurements of contact angle and electron spectroscopy for chemical analysis. The results suggested that the admixture of chitosan decreases wet ability of the specimen and this tendency was slightly enhanced by the biaxially elongation.
(Supercritical) Ammonia for Recycling of Thermoset Polymers
Authors: Mormann Werner , Frank Petra
Published: November 2006

Chemical recycling of thermosetting bisphenol‐A‐polycyanurate, triphenylisocyanurate and of N‐phenylmaleimide (pPMI) as well as 4,4′‐methylenbis‐ (4‐N‐phenylmaleimide) (pBMI) has been studied. Polycyanurate thermosets undergo ammonolytic degradation to the level of oligomeric soluble products already at room temperature, complete degradation to bisphenol‐A and melamine, however requires supercritical conditions (160 °C) and longer reaction times. Polyimides prepared by free radical polymerisation after ammonolysis at 160 °C give the corresponding amines and linear polymers with unsubstituted imide and diamide units. SEC of the polymer analogous (with respect to the carbon chain) reaction products and of linear pPMI shows that the polymers have a polymodal molar mass distribution with a high molar mass and an oligomeric fraction.
Nucleation and Crystallization of PLDA‐b‐PE and PLLA‐b‐PE Diblock Copolymers
Authors: Müller Alejandro J. , Castillo Reina V. , Hillmyer Marc
Published: November 2006

The nucleation and crystallization of two types of strongly segregated poly(lactide)‐block‐polyethylene diblock copolymers with an approximate 50/50 composition has been investigated. One material contains an amorphous PLDA block (PLDA‐b‐PE) and the other contains a semicrystalline PLLA block (PLLA‐b‐PE). The overall isothermal crystallization rate of the PLLA block was slowed down as compared to homo‐PLLA by the covalently bonded PE chains that were molten at the PLLA crystallization temperatures. This crystallization rate depression of the PLLA block produces a coincident crystallization process when PLLA‐b‐PE is cooled down from the melt at rates larger than 2 °C/min. The overall crystallization rate of the PE block is faster when it is covalently bonded to previously crystallized PLLA than when it is attached to a rubbery PDLA block, this results from a nucleation effect of PLLA on the PE block. Polarized Light Optical Microscopy (PLOM) confirmed the confined nature of the crystallization process within lamellar microdomains for both diblock copolymers, since neither PLLA nor PE are capable of breaking out and spherulites can not be formed.
Relaxation Processes in Polymer Surface Layers
Authors: Myasnikova Liubov , Blashenkov Nicolai , Boiko Yurii , Ivan'kova Elena , Kalachev Alexei , Lebedev Dmitrii , Marikhin Vycheslav , Radovanova Elena
Published: November 2006

A recently built and patented device Nanoluminograph is used for the investigation of the relaxation processes in the surface layers of HDPE films, produced at various conditions. The work of the device is based on the phenomenon of radiothermoluminescence. The use of high‐frequency low‐power, low‐temperature plasma as an ionizing source, and a reduction of the consumed energy down to several orders of magnitude (as compared to that used in similar devices) provides excitation of a surface layer as thin as 100–200 nm. The high sensitivity of the device enables one to reduce the excitation time to 1–2 seconds for obtaining a sufficient intensity of glow curves even from ultrathin layers 20–30 nm thick. All of that minimizes the modifying plasma action on the samples under investigation and provides well reproducible and reliable data. It is found that the intensity, number and positions of peaks on the glow curves are strongly influenced by the preparation conditions of polymer films. The complicated profile of glow curve peaks allows one to assume the overlapping of multiple relaxation processes. Decomposing and fitting peak profiles with the help of a PEAKFIT computer program result in revealing at least 4 relaxation transitions in the temperature region from 109 to 213 K. The temperatures and activation energies of relaxation transitions in surface layers appeared to be lower than those inferred from the DSC data for the bulk polymer. The activation energies of trap depletion upon heating are calculated. The nature of traps is discussed in terms of molecular conformations, morphology and structural defects, as well as the attribution of the observed relaxation transitions to defreezing mobility of different kinetic units.
Polymorphism in Nylon‐11: Characterization using HTWAXS and HTFTIR
Authors: Nair Smitha S. , Ramesh C. , Tashiro K.
Published: November 2006

Nylon‐11 was crystallized into different crystalline phases by appropriate methods. The α phase was obtained by precipitating nylon‐11 in 1,4‐butanediol. The melt crystallized sample at 175 °C gave pseudohexagonal phase. The γ phase was obtained by casting nylon‐11 in trifluroacetic acid (TFA). The change in the structure was monitored in situ by high temperature wide‐angle X‐ray scattering (HTWAXS) and high temperature Fourier transform infrared spectroscopy (HTFTIR). The studies have shown that nylon‐11 is one of the few nylons that exhibit extensive degree of polymorphism. HTFTIR studies revealed, apart from the conformational differences between various phases of nylon‐11, some information on the formation of γ phase.
A High Performance Flocculating Agent and Viscosifiers Based On Cationic Guar Gum
Authors: Singh R. P. , Pal Sagar , Mal D.
Published: November 2006

The anionic, cationic and nonionic polymeric flocculants endowed with several distinguished characteristics are being increasingly applied for the treatment of industrial effluents, municipal and wastewater. For the treatment of highly negatively charged particle suspensions, cationic flocculants are more efficient. A new route to guar gum derivatives bearing cationic groups has been developed. A series of cationic guar gums (Cat GG) have been developed by incorporating a cationic moiety N‐ (3‐ Chloro‐2‐ hydroxypropyl) trimethyl ammonium chloride (CHPTAC) onto the backbone of guar gum in presence of NaOH. The various grades of cationic guar gum have been characterized by elemental analysis, FTIR spectroscopy and intrinsic viscosity measurement. The flocculation characteristics of these cationic guar gums have been evaluated in silica suspension by jar test. It has been found that among the various grades of cationic guar gums, the one with longer CHPTAC chains shows better performance. The flocculation characteristics of this best performing cationic guar are compared with those of various commercially available flocculants in silica suspension. Their rheological investigations have also been undertaken.
Controlled Release of Model Drug from Biodegradable Segmented Polyurethane Ureas: Morphological and Structural Features
Authors: Reddy Thatiparti Thimma , Hadano Michiko , Takahara Atsushi
Published: November 2006

Segmented polyurethane ureas (SPUUs), which are being used in implant devices, were evaluated as drug delivery matrices using theophylline as a model drug without much sacrificing the mechanical properties of films after drug doping. SPUUs were synthesized from aliphatic diisocyanate (lysine methyl ester diisocyante (LDI)), poly(caprolactone) diol with molecular weights 530, 1250 and 2000 and 1,4‐butanediamine. Three series of segmented SPUUs were prepared with various soft segment lengths and were characterized by Fourier transform infrared spectroscopy, dynamic viscoelastic measurements and tensile testing. A single tanδ peak was observed in dynamic viscoelastic measurements, which revealed phase mixing of hard and soft segments. Low elongation at break was observed in case of PCL 2000 based SPUUs, may be due to partial cystallization of PCL segment. The degradation of SPUUs in alkaline solution and in vitro drug release of theophylline in pH 7.4 buffer were also investigated. The drug release behavior from these films were analyzed by the exponent relation Mt/M∞ = ktn, where k and n are constants and Mt/M∞ is the fraction of drug released until time, t. The constant n was found to be close to 0.5 in all samples, which suggests the release of drug from these polymers can be explained by the Fickian diffusion model.
Thermally‐Induced Phase Transitions in the Uniaxially‐Oriented δ Form of Syndiotactic Polystyrene
Authors: Gowd E. Bhoje , Shibayama Naoya , Tashiro Kohji
Published: November 2006

The empty δ (δe) form of uniaxially‐oriented syndiotactic polystyrene (sPS) samples were obtained by extracting the solvent molecules from the δ form of sPS and solvent complex in acetone and methanol. Temperature dependence of the X‐ray fiber diagrams starting from the uniaxially‐oriented δe and δ form has been measured successfully at various temperatures for the first time. The transition behavior was traced clearly by separating the equatorial and layer line reflections. The δe form transformed to the γ form via an intermediate form. The intermediate form is speculated to take disordered structure due to the empty cavities present in the δe form. Calorimetric studies showed an endotherm followed by an exotherm during this phase transition, which is consistant with such a speculation. On the other hand the δ form transformed to the γ form directly without passing through the intermediate form or δe form. During the δ to γ phase transition the solvent molecules evaporate through the columnar structure in a broad range of temperature, allowing the transition to occur smoothly.
Structural Study on Water‐induced Phase Transitions of Poly(ethylene imine) as Viewed from the Simultaneous Measurements of Wide‐Angle X‐ray Diffractions and DSC Thermograms
Authors: Hashida Tomoko , Tashiro Kohji
Published: November 2006

Thermal behavior of poly(ethylene imine) [PEI] has been studied using simultaneous WAXD/DSC measurement system. PEI exhibits water‐induced and thermally‐induced phase transitions among four kinds of crystalline hydrates: anhydrate (EI/water = 1/0), hemihydrate (1/0.5), sesquihydrate (1/1.5), and dihydrate (1/2). The chain conformation changes from a double helix in the anhydrate to a planar zigzag form in the three hydrates. The anhydrate melts at 60 °C while the hydrates melt differently in the temperature region of 70–110 °C. By means of the simultaneous WAXD/DSC measurements, complex DSC thermograms of PEI hydrates were characterized on the basis of X‐ray diffractions obtained concurrently.
Structural Study of Phase Transition Behavior of Uniaxially‐Oriented Ethylene‐Tetrafluoroethylene Alternating Copolymer
Authors: Phongtamrug Suttinun , Tashiro Kohji , Funaki Atsushi , Arai Kiyotaka , Aida Shigeru
Published: November 2006

Crystal modifications and phase transition behavior have been investigated for the uniaxially‐oriented ethylene‐tetrafluoroethylene alternating copolymer samples of equimolar content by the temperature‐dependent X‐ray diffraction and Raman spectral measurements. The X‐ray fiber diagram measured for the sample drawn at 0 °C has been found to be quite different from that drawn above 100 °C or the normal orthorhombic‐type sample. The new X‐ray diagram is characterized by the sharpness of the reflections and the positional shift from the horizontal lines, indicating the tilting phenomenon of the crystallites. This sample was found to transform into the hexagonal phase in the temperature region around 110 °C with keeping the tilting phenomenon. The molecular motion of the more or less conformationally disordered chains was enhanced above this transition region as seen from the increase in the half‐width of trans bands and the intensity increment of gauche bands in the Raman spectra.
Confirmation of Disorder α Form of Poly(L‐lactic acid) by the X‐ray Fiber Pattern and Polarized IR/Raman Spectra Measured for Uniaxially‐Oriented Samples
Authors: Zhang Jianming , Tashiro Kohji , Domb Abraham J. , Tsuji Hideto
Published: November 2006

In the present research, we report for the first time the X‐ray fiber pattern and polarized IR/Raman spectra taken for the uniaxially oriented disorder α form of PLLA, which can confirm the existence of the disorder PLLA α form (α′‐form) and provide some new insight on the structural difference between the order and disorder α forms.
The Control of Thermal and Radiation Stability of Polypropylene Containing Calcium Carbonate Nanoparticles
Authors: Zaharescu Traian , Jipa Silviu , Kappel Wilhelm , Supaphol Pitt
Published: November 2006

Thermal and γ radiation stability of iPP containing CaCO3 nanoparticles were investigated by oxygen uptake procedure at 190 °C. The loading of iPP matrix was maximum 25% (w/w). The behavior on thermal oxidation was investigated for two formulations of iPP compounds differing by the surface characteristics of nanoparticles (i.e. uncoated and stearic acid‐coated filler). Three irradiation doses (5, 15 and 25 kGy) were applied. The efficient protection of stabilizers that are present in the as‐prepared formulations was emphasized by proper values of the kinetic parameters obtained for oxidation. The contribution of CaCO3 nanoparticles to the oxidative process of iPP is discussed.
Cover Picture: Macromol. Symp. 242/2006
Authors: Kaneko Takeshi , Suda Kazuya , Satoh Kotaro , Kamigaito Masami , Kato Toshinori , Ono Tomohiro , Nakamura Eiji , Nishi Toshio , Jinnai Hiroshi
Published: November 2006

Cover: The POLYCHAR‐14 World Forum on Advanced Materials took place in April 2006 at Nara Women's University in Nara City, Japan. More than 250 contributions, including 63 invited lectures, presented the state of the art of advanced polymeric materials. Leading scientists from 35 countries discussed the most recent developments in sessions on Characterization, Nanocomposites, Physical Properties, Syntheses, Surface, Interface and Thin Films. A critical selection of the presented contributions has been compiled for this volume. The graphics on the cover are based on results on the ‘ladder’ morphology in an ABC triblock copolymer presented by H. Jinnai et al.
Relationships among symptoms, bother, and treatment satisfaction in overactive bladder patients
Authors: Michel Martin C. , Oelke Matthias , Goepel Mark , Beck Elmar , Burkart Martin
Published: November 2006

Aims

We have studied the association between various symptoms, bother, and patient treatment satisfaction in overactive bladder (OAB).

Methods

Episodes of urgency, incontinence, daytime frequency and nocturia and responses to the patient perception of bladder condition scale, the urgency perception scale, and visual analog scales of limitations in daily life and of treatment satisfaction were evaluated in 3,824 OAB patients at baseline and during 9 months treatment with tolterodine ER (4 mg q.d.) in an open‐label, observational study. Relationships amongst number of symptoms/ 24 hr and scales were explored. Treatment satisfaction was correlated with improvements in symptoms and scales.

Results

At baseline, the number of episodes of the four OAB symptoms correlated only poorly with each other and with the two bother‐related scales, while the two scales assessing bother correlated much stronger with each other. Factor analysis identified four components which described “bother,” “incontinence,” “urgency/frequency,” and “nocturia” and in combination explained 81.9% of the total variance. The component “bother” had the strongest individual effect accounting for 42.1% of the total variance. While improvements of symptoms and bother were seen with tolterodine treatment, patient treatment satisfaction correlated strongest with improvements of the two bother‐related scales.

Conclusions

We conclude that the counting of episodes of OAB symptoms only insufficiently describes the afflicted patients. Patient bother is the strongest individual component but only poorly explained by episodes of the four symptoms defining OAB. Alterations of bother may better reflect patient‐relevant outcomes in OAB treatment than alterations in the number of symptom episodes. Neurourol. Urodynam. 26:190–195, 2007. © 2006 Wiley‐Liss, Inc.
Discontinuous Galerkin methods for periodic boundary value problems
Authors: Vemaganti Kumar
Published: November 2006

This article considers the extension of well‐known discontinuous Galerkin (DG) finite element formulations to elliptic problems with periodic boundary conditions. Such problems routinely appear in a number of applications, particularly in homogenization of composite materials. We propose an approach in which the periodicity constraint is incorporated weakly in the variational formulation of the problem. Both H1 and L2 error estimates are presented. A numerical example confirming theoretical estimates is shown. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2007
Clonal analysis favours a monoclonal origin for serous borderline tumours with peritoneal implants
Authors: Sieben NL , Roemen GMJM , Oosting J , Fleuren GJ , van Engeland M , Prat J
Published: November 2006

Serous borderline tumours (SBTs) of the ovary were originally classified as such because the vast majority behave in a remarkably indolent manner, even in the presence of widespread tumour deposits, termed implants, and/or lymph node involvement. The pathogenesis of the implants is currently unknown. Two major hypotheses have been proposed: the first favours a monoclonal origin, arguing that the peritoneal lesions derive from neoplastic cells that are shed from the primary ovarian tumour. The second hypothesis favours a polyclonal origin as a result of a field defect of susceptible Müllerian cells from which multiple independent tumours arise. To test both hypotheses, genome‐wide allelotyping and B‐RAF/K‐RAS mutation analyses were employed to assess clonality in 25 metachronous or synchronous tumours from ten SBT patients. Loss of heterozygosity (LOH) profiling and K‐RAS/B‐RAF mutation analysis showed concordance of the genetic changes in all sites in 21 tumours from eight patients who were informative. These results favour a common origin, underscored by a likelihood ratio (probability of common origin/probability of independent origin) ranging from 2.43 to 7 662 850. In conclusion, this study strongly supports the hypothesis that both non‐invasive and invasive implants arise as a consequence of spread from a single ovarian site. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Outcome of children treated with preradiation chemotherapy for a high‐grade glioma: Results of a French Society of Pediatric Oncology (SFOP) pilot study
Authors: Chastagner P. , Kalifa C. , Doz F. , Bouffet E. , Gentet J.C. , Ruchoux M.M. , Bracard S. , Desandes E. , Frappaz D.
Published: November 2006

Background

To evaluate the efficacy of BCNU, cisplatin, and vincristine (BCV regimen) in a prospective nonrandomized study among newly diagnosed children with high‐grade glioma.

Procedure

Following surgery, patients received a combination of BCNU + cisplatin + VP16 (BCV), over 3 consecutive days. Patients with residual tumor continued this regimen unless no further improvement was observed on MRI, for a maximum of six courses. Patients who underwent complete surgical resection received six courses of adjuvant BCV.

Results

Seventy‐three patients were enrolled. Out of 66 eligible patients with central pathology review, the diagnosis of high‐grade glioma was confirmed in 53 cases. The response rate was 20%. With a median follow‐up of 128 months, 5‐ and 10‐year event free survival rates are 16 ± 9 and 13.3 ± 9.4%. In univariate analysis, two prognostic factors were statistically significant: extent of resection and tumor location, while macroscopic total resection was the only significant prognostic factor in the multivariate analysis. The response to BCV did not translate into improved event free survival. Interstitial pneumonitis occurred in seven patients, leading to six deaths.

Conclusion

This BCV regimen could not be recommended in the treatment of high‐grade gliomas in children, according to its lack of efficacy and its unacceptable pulmonary toxicity. Pediatr Blood Cancer 2007;49:803–807. © 2006 Wiley‐Liss, Inc.
Functionalization of CNT: synthesis and applications in photovoltaics and biology
Authors: Campidelli Stéphane , Klumpp Cédric , Bianco Alberto , Guldi Dirk M. , Prato Maurizio
Published: November 2006

Here, we review part of the work carried out in our laboratories on carbon nanotube functionalization. Both covalent (sidewall derivatization) and non‐covalent (using π‐π interactions) functionalization have been used to solubilize carbon nanotubes (NTs). The combination of NTs with various electron donors, mainly using the supramolecular approach, led to a new generation of donor‐acceptor nanohybrids which can be used for the development of carbon‐based photovoltaic cells. Covalent functionalization has been successfully applied for preparation of water soluble nanotubes and further derivatization of the nanotubes with bioactive molecules hold great promise for application in drug, vaccine and gene delivery. Copyright © 2006 John Wiley & Sons, Ltd.
Self‐assembled, wormlike‐cylinder network of polystyrene‐block‐poly(ethylene oxide) micelles in solution
Authors: Bhargava Prachur , Zheng Joseph X. , Quirk Roderic P. , Cheng Stephen Z. D.
Published: November 2006

We report the formation of a highly entangled and interconnected, self‐assembled, wormlike‐cylinder network of polystyrene‐block‐poly(ethylene oxide) in N, N‐dimethylformamide/water. In this system, N,N‐dimethylformamide was a common solvent and water was a selective solvent for the poly(ethylene oxide) blocks. The degrees of polymerization of the polystyrene and poly(ethylene oxide) blocks were 962 and 227, respectively. The network was formed at copolymer concentrations higher than 0.4 wt % and consisted of self‐assembled, wormlike cylinders that were interconnected by Y‐shaped, T‐shaped, and multiple junctions. The network morphology was visualized with transmission electron microscopy. Capillary viscometry measurements revealed an order‐of‐magnitude increase in the inherent viscosity of the colloidal system upon the formation of the network. A similar effort to obtain a wormlike‐cylinder network in an N,N‐dimethylformamide/acetonitrile system, in which acetonitrile was a selective solvent for the poly(ethylene oxide) blocks, was unsuccessful even at high copolymer concentrations; instead, the wormlike cylinders showed a tendency to align. The viscosity measurements also did not show a substantial increase in the inherent viscosity. Thus, the solvent played a critical role in determining the formation of the self‐assembled, wormlike‐cylinder network. This formation of the network resulted from an interplay between the end‐capping energy, bending energy (curvature), and configurational entropy of the self‐assembled, wormlike‐cylinder micelles that minimized the free energy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3605–3611, 2006
Orientational anisotropy of bead‐spring star chains during creep process
Authors: Matsumiya Yumi , Inoue Tadashi , Oishi Yohei , Watanabe Hiroshi
Published: November 2006

The bead‐spring model for star chains (Rouse–Ham model) is a fundamental model for the polymer dynamics. Despite the importance of this model, its dynamics under the stress‐controlled condition was not analyzed so far. For completeness of the model, the equation of motion of the Rouse–Ham chain was solved to derive an analytical expression of the orientation function S(n,t) for the stress‐controlled creep process. This expression indicated that the segments near the free end of the star arm exhibit overshoot of their orientational anisotropy to compensate for the slow growth of the anisotropy near the branching point and that the distribution of the anisotropy along the arm contour becomes more heterogeneous with increasing arm number f. This correlation/interplay of the segments at different locations along the arm, not seen under the strain‐controlled condition, is a natural consequence of the constant‐stress requirement during the creep process. The corresponding interplay was noted also for respective Rouse–Ham eigenmodes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3501–3517, 2006