bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and biological significance of CXCR5 expressed by prostate cancer specimens and cell lines
Authors: Singh Shailesh , Singh Rajesh , Singh Udai P. , Rai Shesh N. , Novakovic Kristian R. , Chung Leland W.K. , Didier Peter J. , Grizzle William E. , Lillard James W.
Published: May 2009

Chemokines and chemokine receptors have been shown to be involved in metastatic process of prostate cancer (PCa). In this study, we show primary PCa tissues and cell lines (LNCaP and PC3) express CXCR5, a specific chemokine receptor for CXCL13. Expression of CXCR5 was significantly higher (p < 0.001) in PCa cases than compared to normal match (NM) tissues. CXCR5 intensity correlated (R2 = 0.97) with Gleason score. While prostate tumor tissues with Gleason scores ≥ 7, displayed predominantly nuclear CXCR5 expression patterns, PCa specimens with Gleason scores ≤ 6 showed predominantly membrane and cytoplasmic expression patterns that were comparable to benign prostatic hyperplasia (BPH). Similar to tissue expression, PCa cell lines expressed significantly more CXCR5 than normal prostatic epithelial cells (PrECs), and CXCR5 expression was distributed among intracellular and extracellular compartments. Functional in vitro assays showed higher migratory and invasive potentials toward CXCL13, an effect that was mediated by CXCR5. In both PCa cell lines, CXCL13 treatment increased the expression of collagenase‐1 or matrix metalloproteinase‐1 (MMP‐1), collagenase‐3 (MMP‐13), stromelysin‐1 (MMP‐3), stromelysin‐2 (MMP‐10) and stromelysin‐3 (MMP‐11). These data demonstrate the clinical and biological relevance of the CXCL13‐CXCR5 pathway and its role in PCa cell invasion and migration. © 2009 UICC
Subcellular localization of antizyme inhibitor 2 in mammalian cells: Influence of intrinsic sequences and interaction with antizymes
Authors: López‐Contreras Andrés J. , Sánchez‐Laorden Berta L. , Ramos‐Molina Bruno , de la Morena María E. , Cremades Asunción , Peñafiel Rafael
Published: May 2009

Ornithine decarboxylase (ODC) and the antizyme inhibitors (AZIN1 and AZIN2), regulatory proteins of polyamine levels, are antizyme‐binding proteins. Although it is widely recognized that ODC is mainly a cytosolic enzyme, less is known about the subcellular distribution of AZIN1 and AZIN2. We found that these proteins, which share a high degree of homology in their amino acid sequences, presented differences in their subcellular location in transfected mammalian cells. Whereas ODC was mainly present in the cytosol, and AZIN1 was found predominantly in the nucleus, interestingly, AZIN2 was located in the ER‐Golgi intermediate compartment (ERGIC) and in the cis‐Golgi network, apparently not related to any known cell‐sorting sequence. Our results rather suggest that the N‐terminal region may be responsible for this particular location, since its deletion abrogated the incorporation of the mutated AZIN2 to the ERGIC complex and, on the other hand, the substitution of this sequence for the corresponding sequence in ODC, translocated ODC from cytosol to the ERGIC compartment. Furthermore, the coexpression of AZIN2 with any members of the antizyme family induced a shift of AZIN2 from the ERGIC to the cytosol. These findings underline the complexity of the AZs/AZINs regulatory system, supporting early evidence that relates these proteins with additional functions other than regulating polyamine homeostasis. J. Cell. Biochem. 107: 732–740, 2009. © 2009 Wiley‐Liss, Inc.
Multi‐component stable isotope records from Late Weichselian and early Holocene lake sediments at Imiołki, Poland: palaeoclimatic and methodological implications
Authors: Apolinarska Karina , Hammarlund Dan
Published: May 2009

Late Weichselian and early Holocene climatic and environmental changes are inferred from stable carbon and oxygen isotope records obtained on bulk and biogenic carbonates from the sediment sequence of Lake Lednica, western Poland. Along with sediment and pollen stratigraphic data, a wide range of carbonate components occurring in the sediments was analysed forδ13C andδ18O, including shells of several gastropod species and the bivalve genusPisidium, carapaces of the ostracod subfamily Candoninae and oogonia of the aquatic macrophyte genusChara. The development of catchment soils and the onset of authigenic carbonate production in response to the climatic amelioration during the Late Weichselian are clearly reflected by rising carbonate content, distinct isotopic shifts in bulk carbonates and decreasingδ13C values of bulk organic matter in the sediments. The GI‐1/GS‐1 (the Bølling–Allerød Interstadial complex/Younger Dryas Stadial) and the GS‐1/Preboreal transitions are marked by significant shifts inδ18O values of 2–3‰, as well as by distinct changes in carbonate content, indicative of a decrease and a subsequent increase in mean annual temperature. Correspondingδ13C records reflect primarily changes in aquatic productivity, with favourable conditions for phytoplankton and macrophytes during GI‐1 and the Preboreal resulting in persistent13C enrichment. The Younger Dryas Stadial is characterised by depletions in13C and18O, with indications of a climatic tripartition. Consistent offsets inδ13C andδ18O between records obtained on specific carbonate components reflect vital effects in combination with seasonal characteristics and habitat preferences of the respective carbonate‐precipitating biota. Largely parallel first‐order variations inδ13C andδ18O of the different carbonate components demonstrate that individual isotope records may provide important palaeoclimatic information, although more detailed reconstructions can be obtained from multi‐component analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Hot water acid‐resistant enamels for sheet steel
Authors: Kassem A. S. , Mostafa M. Z. , Abadir M. F. , Sherbiny S. A. El
Published: May 2009

Several enamel frit recipes were formulated for direct‐on application on sheet steel. Their suitability as hot water and acid‐resistant coatings were investigated. DTA analyses were performed on raw batches to follow up physico‐chemical changes occurring on firing. Then batches with different recipe compositions were fritted and mixed with mill additions. These were then tested for thermal expansion and the corresponding linear coefficients as well as glass transition temperatures and softening points were obtained. Also, the viscosity of molten frits was determined as a function of temperature. These frits were then applied on sheet steel and the following properties were investigated: resistance to hot water, acid resistance, surface gloss, and adherence to steel. It was found that recipe No. 4, containing no manganese dioxide and the highest amount of nickel oxide among all the suggested recipes, gave the best results. The optimum conditions for application on steel sheet were: firing at 850 °C for 5 min.
Effect of Ag addition on the corrosion properties of Sn‐based solder alloys
Authors: Bui Q. V. , Nam N. D. , Noh B.‐I. , Kar A. , Kim J.‐G. , Jung S.‐B.
Published: May 2009

Corrosion properties of three different Sn‐Ag lead free solder alloys have been investigated in 0.3 wt% Na2SO4 solution as corrosive environment. As cast solder alloy was analyzed by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Volume fractions of the Ag3Sn in the solders were determined by image analysis technique. Pitting potential and corrosion potential for the alloys were determined by potentiodynamic tests. Electrochemical impedance spectroscopy (EIS) was carried out to measure the film and charge transfer resistance. Alloys with lower Ag content have been found as better corrosion resistance material.
A note on substitutions in representable cylindric algebras
Authors: Ahmed Tarek Sayed
Published: May 2009

We show that it is impossible to define a substitution operator for arbitrary representable cylindric algebras that agrees in its basic properties with the notion of substitutions introduced for dimension complemented algebras (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of a novel oligomeric intumescent flame retardant and its application in polypropylene
Authors: Song Pingan , Fang Zhengping , Tong Lifang , Xu Zhongbin
Published: May 2009

A novel oligomeric phosphorous‐nitrogen containing intumescent flame retardant, poly (4,4‐diamino diphenyl methane‐O‐bicycli pentaerythritol phosphate‐phosphate) (PDBPP), was synthesized and characterized. Thermal stability and flammability properties of polypropylene (PP)/PDBPP composites with various PDBPP loading were investigated by thermogravimetric analysis (TGA), limited oxygen index (LOI), and cone calorimeter, respectively. The results showed that the incorporation of PDBPP could improve both the thermal stability and flame retardancy of PP considerably. PP/30%PDBPP system had a LOI value of 28 and its peak heat release rate was reduced by 60% relative to pure PP. Infrared spectrum and field emission scanning electron microscope measurements revealed that PDBPP and PP/PDBPP composites would form a continuous multicellular char layer containing phosphoric acid when exposed to elevated temperature. It was suggested that the very char layer was responsible for the enhanced thermal stability and improved flame retardancy. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Nonisothermal thermophysical evaluation of polypropylene/natural rubber based TPEs: Effect of blend ratio and dynamic vulcanization
Authors: Joseph Aju , Lüftl Sigrid , Seidler Sabine , Thomas Sabu , Joseph Kuruvilla
Published: May 2009

Ozawa macrokinetic model is applied to describe the nonisothermal melt crystallization process of polypropylene (PP), in natural rubber/polypropylene (NR/PP) thermoplastic elastomers (TPEs) as a function of blend ratio and dynamic vulcanization of the rubber phase. It was found that as cooling rate increases, the crystallization temperature Tc and half time for crystallization t1/2 get diminished. Dynamic vulcanizates show a similar trend in crystallization as that of neat PP. Crystallization rate constant and Ozawa exponent were found out for different temperatures by linear regression method using Ozawa analysis. Ozawa exponent, nO, showed variation in values when the conversion proceeded. For neat PP, the value of nO changes from 1.4 (102°C) to 3 (112°C). The nO values for NR/PP 50/50 blend were higher (e.g. 4.1 at 116°C). Crystallization rate constant KO shows a maximum at 0.5 relative crystallinity. The highest crystallization rate constants were found for NR/PP 50/50 TPEs. The activation energy for the melt crystallization was found to vary with the degree of conversion, as well as with the concentration of NR in the TPEs. Finally, attempts have been made to correlate the crystallization process with morphology of the blend. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Melting behavior, isothermal and nonisothermal crystallization kinetics of nylon 1111
Authors: Jiang Tao , Liu Minying , Fu Peng , Wang Yudong , Fang Yunli , Zhao Qingxiang
Published: May 2009

The isothermal and nonisothermal crystallization kinetics of nylon 1111 was extensively studied using differential scanning calorimetry (DSC). The equilibrium melting temperature of nylon 1111 was determined to be 188°C. In this article, the Avrami equation was used to describe the isothermal crystallization behavior of nylon 1111. On the basis of the DSC results, the Avrami exponent, n, was determined to be around 3 during the isothermal crystallization process. Nonisothermal crystallization was analyzed using both the Avrami equation as modified by Jeziorny and an equation suggested by Mo. The larger value of the Avrami exponent, n, during the nonisothermal crystallization process indicates that the development of nucleation and crystal growth are more complicated during the nonisothermal crystallization for nylon 1111, and that the nucleation mode might simultaneously include both homogeneous and heterogeneous nucleations. The isothermal and nonisothermal crystallization activation energies of nylon 1111 were determined to be −132 kJ/mol and −121 kJ/mol using the Arrhenius equation and the Kissinger method, respectively. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
RAFT copolymerization of methacrylic acid and poly(ethylene glycol) methyl ether methacrylate in the presence of a hydrophobic chain transfer agent in organic solution and in water
Authors: Rinaldi David , Hamaide Thierry , Graillat Christian , D'Agosto Franck , Spitz Roger , Georges Sébastien , Mosquet Martin , Maitrasse Philippe
Published: May 2009

RAFT polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA, 1100 g mol−1) was first performed using cyanoisopropyl dithiobenzoate (CPDB). The control of PEGMA homopolymerization, carried out in THF ([PEGMA] = 40 wt %) at 65 °C (reflux) using 2,2′‐Azobis(isobutyronitrile) (AIBN) as initiator, was shown by the linear increase of molar masses and the low polydispersity indices (PDI) observed with conversion and also by the determination of a high chain transfer constant (Ctr = 9.1) for CPDB in this system. Copolymerization of PEGMA with methacrylic acid (MAA) ([PEGMA]/[MAA] = 40/60) was then undertaken first in dioxane at 85 °C. High conversion (89%) was obtained in 3 h without any composition drift and with a good level of control (PDI < 1.40). When the polymerization was performed in water, a strong increase in polymerization rate was observed with almost quantitative conversion (98%) in 2 h without affecting the level of control of the final copolymers (PDI ∼ 1.30). These last results were tentatively explained by the formation of hydrophobic domains in which the polymerization occurred as in bulk. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3045–3055, 2009
Conjugated polyelectrolyte with pendant carboxylate groups: Synthesis, photophysics, and pH responses in the presence of surfactants
Authors: Zhang Tao , Fan Hongliang , Zhou Jianguang , Jin Qinhan
Published: May 2009

This article reports the synthesis, optical properties, and pH responses of a water‐soluble poly(phenylene ethynylene) with pendant carboxylate groups. This conjugated polyelectrolyte, PPE‐OBS, was prepared via a facile synthetic route, using 1,4‐di(ethyl 4‐oxy‐butyrate)‐2,5‐diiodo‐benzene as polymeric monomer and followed by the alkali induced saponification. PPE‐OBS absorbs strongly in the blue region and emits a moderately intense fluorescence. However, it subjects to unstable emission in neutral aqueous media, which is believed to arise because the polymer tends to become more hydrophobic via protonation and to form much heavier aggregates (clusters). Subsequent studies on the interaction and stabilization of PPE‐OBS with various surfactants indicate that its fluorescence stability can be largely improved in the presence of a small amount of surfactant. More interestingly, even at low pH, the surfactant‐stabilized polyelectrolyte with its pendant groups being COOH rather than COO− remains water‐soluble and emits efficiently, which is expected of great significance for the covalent linkage to bio‐molecules. In addition, the sensitive pH response in emission spectrum of PPE‐OBS/surfactant complex over a relatively wide range suggests surely a potential access to the fluorescent sensing of pH variation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3056–3065, 2009
Polymerization of branched thiophene monomers and optoelectronic properties of materials
Authors: Takagi Koji , Torii Chikako , Yamashita Yusuke
Published: May 2009

Bithiophene monomers (5HBTh and 5HBThO) were prepared by the Suzuki coupling reaction of 3‐thienylboronic acid with 2‐bromo‐5‐hexylthiophene and 2‐bromo‐5‐hexylthiophene‐1,1‐dioxide. The oxidation polymerization mediated by vanadium catalyst gave poly(5HBTh) and oligo(5HBThO). 5HBThO bearing thiophene‐1,1‐dioxide had an absorption maximum at longer wavelength region than 5HBTh due to the intramolecular charge transfer interaction, while peak maxima blue shifted and their difference became small after the polymerization. Terthiophene monomers (5″HTTh, 3,5″DHTTh, and 4,5″DHTTh) were subsequently prepared by the mono‐bromination of 5HBTh followed by the Suzuki coupling reaction with boronic acid derivatives. The vanadium‐catalyzed oxidation polymerization of 5″HTTh and 4,5″DHTTh afforded soluble polymers and the absorption maximum wavelengths red shifted after the polymerization in contrast to bithiophene monomers and 3,5″DHTTh. The absorption and emission spectra of poly(5″DHTTh) red shifted when compared with those of poly(4,5″DHTTh). Thus the presence and position of n‐hexyl chain influenced the monomer polymerizability and optoelectronic properties of branched polythiophenes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3034–3044, 2009
N‐(2‐benzimidazolylquinolin‐8‐yl)benzamidate half‐titanocene chlorides: Synthesis, characterization and their catalytic behavior toward ethylene polymerization
Authors: Liu Shaofeng , Yi Jianjun , Zuo Weiwei , Wang Kefeng , Wang Deligeer , Sun Wen‐Hua
Published: May 2009

A series of N‐(2‐benzimidazolyquinolin‐8‐yl)benzamidate half‐titanocene chlorides, Cp′TiLCl (C1–C8: Cp′ = C5H5, MeC5H4, or C5Me5; L = N‐(benzimidazolyquinolin‐8‐yl)benzamides)), was synthesized by the KCl elimination reaction of half‐titanocene trichlorides with the correspondent potassium N‐(2‐benzimidazolyquinolin‐8‐yl)benzamide. These half‐titanocene complexes were fully characterized by elemental and NMR analyses, and the molecular structures of complexes C2 and C8 were determined by the single‐crystal X‐ray diffraction. The high stability of the pentamethylcyclopentadienyl complex (C8) was evident by no decomposing nature of its solution in air for one week. The oxo‐bridged dimeric complex (C9) was isolated from the solution of the corresponding cyclopentadienyl complex (C3) solution in air. Complexes C1–C8 exhibited good to high catalytic activities toward ethylene polymerization and ethylene/α‐olefin copolymerization in the presence of methylaluminoxane (MAO) cocatalyst. In the typical catalytic system of C1/MAO, the polymerization productivities were enhanced with either elevating reaction temperature or increasing the ratio of MAO to titanium precursor. In general, it was observed that higher the catalytic activity of the catalytic system lower the molecular weight of polyethylene. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3154–3169, 2009
How oncologists and their patients with advanced cancer communicate about health‐related quality of life
Authors: Rodriguez Keri L. , Bayliss Nichole , Alexander Stewart C. , Jeffreys Amy S. , Olsen Maren K. , Pollak Kathryn I. , Kennifer Sarah L. , Tulsky James A. , Arnold Robert M.
Published: May 2009

Objective: To describe the content and frequency of communication about health‐related quality of life (HRQOL) during outpatient encounters between oncologists and their patients with advanced cancer.

Methods: We coded for HRQOL talk in a subset of audio‐recorded conversations (each previously found to contain prognostic talk by the oncologist) from the Study of Communication in Oncologist–Patient Encounters Trial, a randomized controlled trial conducted from 2003 to 2008 in two large US academic medical centers and one Veterans Affairs Medical Center.

Results: Seventy‐three encounters involved 70 patients and 37 oncologists. Patients were more likely to be female (53%), White (86%), married (78%), and possessing some college education (62%). Most oncologists were male (78%) and White (78%). Mean ages were 59 years for patients and 44 years for oncologists. Every encounter included some talk about HRQOL and HRQOL discussions made up, on average, 25% of the visit time. HRQOL segments described symptoms (50%), general HRQOL (27%), and the following concerns: physical (27%), functional (22%), psychological (9%), social (7%), spiritual (1%), and other (28%). Topics included treatment (56%), disease (14%), and testing (3%), and conversations focused on past (44%), present (68%), and future HRQOL (59%).

Conclusions: HRQOL discussions between oncologists and patients are common, but the emphasis is often on treatment (e.g. side effects) and symptoms (e.g. pain) even in patients with advanced disease. Given the often intense emotional experience of patients with advanced cancer, oncologists may need to pay more attention to psychological, social, and spiritual HRQOL concerns. Copyright © 2009 John Wiley & Sons, Ltd.
Safety and tolerability of montelukast in placebo‐controlled pediatric studies and their open‐label extensions
Authors: Bisgaard Hans , Skoner David , Boza Maria L. , Tozzi Carol A. , Newcomb Kathleen , Reiss Theodore F. , Knorr Barbara , Noonan Gertrude
Published: May 2009

Background

Montelukast is a potent leukotriene‐receptor antagonist administered once daily that provides clinical benefit in the treatment of asthma and allergic rhinitis in children and adults. Because of its wide use as a pediatric controller, there is a need for a further review of the safety and tolerability of montelukast in children.

Objective

To summarize safety and tolerability data for montelukast from previously reported as well as from unpublished placebo‐controlled, double‐blind, pediatric studies and their active‐controlled open‐label extension/extended studies.

Methods

These studies evaluated 2,751 pediatric patients 6 months to 14 years of age with persistent asthma, intermittent asthma associated with upper respiratory infection, or allergic rhinitis. These patients were enrolled in seven randomized, placebo‐controlled, double‐blind registration and post‐registration studies and three active‐controlled open‐label extension/extended studies conducted by Merck Research Laboratories between 1995 and 2004.

Results

Montelukast was well tolerated in all studies. Clinical and laboratory adverse experiences for patients treated with montelukast were generally mild and transient. The most frequent clinical adverse events for all treatments (placebo, montelukast, active control/usual care) in virtually all studies were upper respiratory infection, worsening asthma, pharyngitis, and fever.

Conclusion

The clinical and laboratory safety profile for montelukast was similar to that observed for placebo or active control/usual care therapies. The safety profile of montelukast did not change with long‐term use. Pediatr Pulmonol. 2009; 44:568–579. © 2009 Wiley‐Liss, Inc.
Phosphonium labeling for increasing metabolomic coverage of neutral lipids using electrospray ionization mass spectrometry
Authors: Woo Hin‐Koon , Go Eden P. , Hoang Linh , Trauger Sunia A. , Bowen Benjamin , Siuzdak Gary , Northen Trent R.
Published: May 2009

Mass spectrometry has become an indispensable tool for the global study of metabolites (metabolomics), primarily using electrospray ionization mass spectrometry (ESI‐MS). However, many important classes of molecules such as neutral lipids do not ionize well by ESI and go undetected. Chemical derivatization of metabolites can enhance ionization for increased sensitivity and metabolomic coverage. Here we describe the use of tris(2,4,6,‐trimethoxyphenyl)phosphonium acetic acid (TMPP‐AA) to improve liquid chromatography (LC)/ESI‐MS detection of hydroxylated metabolites (i.e. lipids) from serum extracts. Cholesterol which is not normally detected from serum using ESI is observed with attomole sensitivity. This approach was applied to identify four endogenous lipids (hexadecanoyl‐sn‐glycerol, dihydrotachysterol, octadecanol, and alpha‐tocopherol) from human serum. Overall, this approach extends the types of metabolites which can be detected using standard ESI‐MS instrumentation and demonstrates the potential for targeted metabolomics analysis. Published in 2009 by John Wiley & Sons, Ltd.
Characterization of dihydrostreptomycin‐related substances by liquid chromatography coupled to ion trap mass spectrometry
Authors: Pendela Murali , Hoogmartens Jos , Van Schepdael Ann , Adams Erwin
Published: May 2009

Dihydrostreptomycin sulphate (DHS) is a water‐soluble, broad‐spectrum aminoglycoside antibiotic. For quantitative analysis, the European Pharmacopoeia (Ph. Eur.) prescribes an ion‐pairing liquid chromatography/ultraviolet (LC/UV) method using a C18 stationary phase. Several unknown compounds were detected in commercial samples. Hence, for characterization of these unknown peaks in a commercial DHS sample, the Ph. Eur. method was coupled to mass spectrometry (MS). However, since the Ph. Eur. method uses a non‐volatile mobile phase, each peak eluted was collected and desalted before introduction into the mass spectrometer. The desalting procedure was applied to remove the non volatile salt, buffer and ion‐pairing reagent in the collected fraction. In total, 20 impurities were studied and 14 of them were newly characterized. Five impurities which are already reported in the literature were also traced in this LC/UV method. Copyright © 2009 John Wiley & Sons, Ltd.
Automatic identification of otologic drilling faults: a preliminary report
Authors: Shen Peng , Feng Guodong , Cao Tianyang , Gao Zhiqiang , Li Xisheng
Published: May 2009

Background

A preliminary study was carried out to identify parameters to characterize drilling faults when using an otologic drill under various operating conditions.

Methods

An otologic drill was modified by the addition of four sensors. Under consistent conditions, the drill was used to simulate three important types of drilling faults and the captured data were analysed to extract characteristic signals. A multisensor information fusion system was designed to fuse the signals and automatically identify the faults.

Results

When identifying drilling faults, there was a high degree of repeatability and regularity, with an average recognition rate of >70%.

Conclusions

This study shows that the variables measured change in a fashion that allows the identification of particular drilling faults, and that it is feasible to use these data to provide rapid feedback for a control system. Further experiments are being undertaken to implement such a system. Copyright © 2009 John Wiley & Sons, Ltd.
Using the PhysX engine for physics‐based virtual surgery with force feedback
Authors: Maciel Anderson , Halic Tansel , Lu Zhonghua , Nedel Luciana P. , De Suvranu
Published: May 2009

Background

The development of modern surgical simulators is highly challenging, as they must support complex simulation environments. The demand for higher realism in such simulators has driven researchers to adopt physics‐based models, which are computationally very demanding. This poses a major problem, since real‐time interactions must permit graphical updates of 30 Hz and a much higher rate of 1 kHz for force feedback (haptics). Recently several physics engines have been developed which offer multi‐physics simulation capabilities, including rigid and deformable bodies, cloth and fluids. While such physics engines provide unique opportunities for the development of surgical simulators, their higher latencies, compared to what is necessary for real‐time graphics and haptics, offer significant barriers to their use in interactive simulation environments.

Methods

In this work, we propose solutions to this problem and demonstrate how a multimodal surgical simulation environment may be developed based on NVIDIA's PhysX physics library. Hence, models that are undergoing relatively low‐frequency updates in PhysX can exist in an environment that demands much higher frequency updates for haptics. We use a collision handling layer to interface between the physical response provided by PhysX and the haptic rendering device to provide both real‐time tissue response and force feedback.

Results

Our simulator integrates a bimanual haptic interface for force feedback and per‐pixel shaders for graphics realism in real time. To demonstrate the effectiveness of our approach, we present the simulation of the laparoscopic adjustable gastric banding (LAGB) procedure as a case study.

Conclusions

To develop complex and realistic surgical trainers with realistic organ geometries and tissue properties demands stable physics‐based deformation methods, which are not always compatible with the interaction level required for such trainers. We have shown that combining different modelling strategies for behaviour, collision and graphics is possible and desirable. Such multimodal environments enable suitable rates to simulate the major steps of the LAGB procedure. Copyright © 2009 John Wiley & Sons, Ltd.
Immersion and invariance‐based impedance control for electrohydraulic systems
Authors: Kemmetmüller W. , Kugi A.
Published: May 2009

This work deals with the impedance control of electrohydraulic systems based on the concept of immersion and invariance. In the first step, the impedance control task for a basic electrohydraulic system comprising a hydraulic cylinder and a 4/3 proportional valve is analyzed. In order to mitigate the problem of energetic inefficiency and the high demands on the dynamics of the valve, an extended electrohdydraulic system is proposed. By means of a suitable choice of the parameters and an immersion and invariance‐based controller strategy, a significant reduction of both energy consumption and required dynamics of the valve can be obtained. The feasibility of the proposed impedance control strategies is demonstrated by extensive simulation studies. Copyright © 2009 John Wiley & Sons, Ltd.
Method for Quantitative and Molecular Characterisation of Adsorbed Starch Polysaccharides on a Papermaking Pulp by SEC‐MALLS Measurements and Correlation with Paper Strength
Authors: Ulbrich Marco , Radosta Sylvia , Vorwerg Waltraud
Published: May 2009

A laboratory‐scale method for determining the molecularly dispersed amount of cationic starch adsorbed on a papermaking pulp was developed. The starch was molecularly dispersed by pressure cooking and was characterised by SEC‐MALLS (Size Exclusion with Multi‐Angle Laser Light Scattering) before and after the adsorption experiment. The adsorbed amount was calculated from the depletion of starch polymers in the starch‐fibre suspension. The molecular composition of the adsorbed starch product was determined from the difference in the SEC chromatograms before and after adsorption. In addition, handsheets were formed to correlate starch adsorption on the pulp with the resulting paper strength. The value of the method was demonstrated using the example of a low DS cationic potato starch derivative. This sample from a slurry process was adsorbed to a significantly higher extent in virtually electrolyte‐free deionised water (DW) than in water with a high electrolyte content (36 degrees German Hardness – 36 dGH). In DW, both amylopectin and amylose were adsorbed on the pulp, whereas in water of 36 dGH only the amylopectin‐rich fraction was adsorbed. A correlation between starch adsorption as a function of water quality and the resulting paper strength was found. The amount and molecular composition of the adsorbed starch product influenced paper properties.
Epidermal Growth Factor Induces the Progeny of Subventricular Zone Type B Cells to Migrate and Differentiate into Oligodendrocytes
Authors: Gonzalez-Perez Oscar , Romero-Rodriguez Ricardo , Soriano-Navarro Mario , Garcia-Verdugo Jose Manuel , Alvarez-Buylla Arturo
Published: May 2009

New neurons and oligodendrocytes are continuously produced in the subventricular zone (SVZ) of adult mammalian brains. Under normal conditions, the SVZ primary precursors (type B1 cells) generate type C cells, most of which differentiate into neurons, with a small subpopulation giving rise to oligodendrocytes. Epidermal growth factor (EGF) signaling induces dramatic proliferation and migration of SVZ progenitors, a process that could have therapeutic applications. However, the fate of cells derived from adult neural stem cells after EGF stimulation remains unknown. Here, we specifically labeled SVZ B1 cells and followed their progeny after a 7-day intraventricular infusion of EGF. Cells derived from SVZ B1 cells invaded the parenchyma around the SVZ into the striatum, septum, corpus callosum, and fimbria-fornix. Most of these B1-derived cells gave rise to cells in the oligodendrocyte lineage, including local NG2+ progenitors, and premyelinating and myelinating oligodendrocytes. SVZ B1 cells also gave rise to a population of highly-branched S100β+/glial fibrillary acidic protein (GFAP)+ cells in the striatum and septum, but no neuronal differentiation was observed. Interestingly, when demyelination was induced in the corpus callosum by a local injection of lysolecithin, an increased number of cells derived from SVZ B1 cells and stimulated to migrate and proliferate by EGF infusion differentiated into oligodendrocytes at the lesion site. This work indicates that EGF infusion can greatly expand the number of progenitors derived from the SVZ primary progenitors which migrate and differentiate into oligodendroglial cells. This expanded population could be used for the repair of white matter lesions.

Disclosure of potential conflicts of interest is found at the end of this article.
Initiation of Dopaminergic Differentiation of Nurr1− Mesencephalic Precursor Cells Depends on Activation of Multiple Mitogen-Activated Protein Kinase Pathways
Authors: Sabolek Michael , Baumann Bernd , Heinrich Maria , Meyer Anne K. , Herborg Anna , Liebau Stefan , Maisel Martina , Hermann Andreas , Ventz Katharina , Schwarz Johannes , Wirth Thomas , Storch Alexander
Published: May 2009

Interleukin-1 (IL-1) plays a pivotal role in terminal dopaminergic differentiation of midbrain-derived neural precursor cells already committed to the mesencephalic dopaminergic phenotype (named mdNPCs for mesencephalic dopaminergic neural precursor cells). Here we characterized the molecular events in long-term expanded rat nuclear receptor related-1− (Nurr1−) mdNPCs in response to IL-1β during their terminal dopaminergic specification. We showed that IL-1β induced a rapid induction of mRNA of dopaminergic key fate-determining transcription factors, such as Nurr1 and Pitx3, and a subsequent increase of tyrosine hydroxylase protein as an early marker for dopaminergic neurons in vitro. These effects of IL-1β were specific for mdNPCs and were not observed in striatal neural precursor cells (NPCs). Surprisingly, IL-1β did not activate the NF-κB pathway or the transcription factor activating protein 1 (AP-1), but inhibition of nuclear translocation of NF-κB by SN50 facilitated IL-1β-induced Nurr1 expression and dopaminergic differentiation of mdNPCs. Incubation of mdNPCs with IL-1β led to a rapid phosphorylation of ERK1/2 and p38 mitogen-activated protein (MAP) kinases within 1 to 3 hours, whereas Jun kinase was not phosphorylated in response to IL-1β. Consistently, inhibition of the ERK1/2 pathway or p38 MAP kinase blocked Nurr1 upregulation and further dopaminergic specification of mdNPCs, but not differentiation into MAP2ab+ neurons. IL-1 receptor antagonist did not block early dopaminergic differentiation events, suggesting that the effects of IL-1β are not mediated through activation of IL-1 receptor type I. Our results indicate that induction of terminal dopaminergic specification of Nurr1− mdNPCs by IL-1β depends on activation of the ERK1/2 and p38 MAP kinase pathway.

Disclosure of potential conflicts of interest is found at the end of this article.
Ionizing Radiation Induces Ataxia Telangiectasia Mutated-Dependent Checkpoint Signaling and G2 But Not G1 Cell Cycle Arrest in Pluripotent Human Embryonic Stem Cells
Authors: Momčilović Olga , Choi Serah , Varum Sandra , Bakkenist Christopher , Schatten Gerald , Navara Christopher
Published: May 2009

Human embryonic stem (ES) cells are highly sensitive to environmental insults including DNA damaging agents, responding with high levels of apoptosis. To understand the response of human ES cells to DNA damage, we investigated the function of the ataxia telangiectasia mutated (ATM) DNA damage signaling pathway in response to γ-irradiation. Here, we demonstrate for the first time in human ES cells that ATM kinase is phosphorylated and properly localized to the sites of DNA double-strand breaks within 15 minutes of irradiation. Activation of ATM kinase resulted in phosphorylation of its downstream targets: Chk2, p53, and Nbs1. In contrast to murine ES cells, Chk2 and p53 were localized to the nucleus of irradiated human ES cells. We further show that irradiation resulted in a temporary arrest of the cell cycle at the G2, but not G1, phase. Human ES cells resumed cycling approximately 16 hours after irradiation, but had a fourfold higher incidence of aberrant mitotic figures compared to nonirradiated cells. Finally, we demonstrate an essential role of ATM in establishing G2 arrest since inhibition with the ATM-specific inhibitor KU55933 resulted in abolishment of G2 arrest, evidenced by an increase in the number of cycling cells 2 hours after irradiation. In summary, these results indicate that human ES cells activate the DNA damage checkpoint, resulting in an ATM-dependent G2 arrest. However, these cells re-enter the cell cycle with prominent mitotic spindle defects.

Disclosure of potential conflicts of interest is found at the end of this article.
Smad, PI3K/Akt, and Wnt-Dependent Signaling Pathways Are Involved in BMP-4-Induced ESC Self-Renewal
Authors: Lee Min Young , Lim Hyun Woo , Lee Sang Hun , Han Ho Jae
Published: May 2009

It is known that bone morphogenetic protein 4 (BMP-4) has a diverse effect on ESCs. However, its precise mechanism in mouse ESCs is not fully understood. We evaluated the effect of BMP-4 on ESC proliferation and its related signal cascades in this study. BMP-4 significantly increased the level of [3H]-thymidine incorporation in time- (≥8 hours) and dose- (≥10 ng/ml) dependent manners. Additionally, BMP-4 increased cyclin D1 and decreased p27kip1 expression values in a time-dependent manner. The increases in BMP-4-induced [3H]-thymidine incorporation and cyclin D1 expression were inhibited by the BMP-4 receptor antagonist noggin. BMP-4 increased Wnt1 expression. Wnt1 expression was attenuated by Smad4 small interfering RNA (siRNA), and BMP-4-induced cyclin D1 expression was inhibited by Smad4 and Wnt1 siRNAs. BMP-4 also activated β-catenin, which was blocked by Smad4 and Wnt1 siRNAs. In addition, BMP-4 induced Akt phosphorylation. BMP-4-induced β-catenin activation and cyclin D1 expression were attenuated by phosphatidyl inositol 3-kinase (PI3K) siRNA and Akt inhibitor. Additionally, downregulation of Smad4, Wnt1, and PI3K expression by siRNA decreased the levels of pluripotency marker mRNAs of ESCs, including Oct4, Sox2, and FoxD3. Our results suggested that BMP-4-induced [3H]-thymidine incorporation was significantly attenuated by Smad4, Wnt1, and PI3K knockdown. In conclusion, BMP-4 contributed to the maintenance of cell proliferation and the pluripotent state by Smad, PI3K/Akt, and Wnt1/β-catenin in mouse ESCs.

Disclosure of potential conflicts of interest is found at the end of this article.
A Complex Role for FGF-2 in Self-Renewal, Survival, and Adhesion of Human Embryonic Stem Cells
Authors: Eiselleova Livia , Matulka Kamil , Kriz Vitezslav , Kunova Michaela , Schmidtova Zuzana , Neradil Jakub , Tichy Boris , Dvorakova Dana , Pospisilova Sarka , Hampl Ales , Dvorak Petr
Published: May 2009

The transcription program that is responsible for the pluripotency of human ESCs (hESCs) is believed to be comaintained by exogenous fibroblast growth factor-2 (FGF-2), which activates FGF receptors (FGFRs) and stimulates the mitogen-activated protein kinase (MAPK) pathway. However, the same pathway is stimulated by insulin receptors, insulin-like growth factor 1 receptors, and epidermal growth factor receptors. This mechanism is further complicated by intracrine FGF signals. Thus, the molecular mechanisms by which FGF-2 promotes the undifferentiated growth of hESCs are unclear. Here we show that, in undifferentiated hESCs, exogenous FGF-2 stimulated the expression of stem cell genes while suppressing cell death and apoptosis genes. Inhibition of autocrine FGF signaling caused upregulation of differentiation-related genes and downregulation of stem cell genes. Thus, exogenous FGF-2 reinforced the pluripotency maintenance program of intracrine FGF-2 signaling. Consistent with this hypothesis, expression of endogenous FGF-2 decreased during hESC differentiation and FGF-2 knockdown-induced hESC differentiation. In addition, FGF-2 signaling via FGFR2 activated MAPK kinase/extracellular signal-regulated kinase and AKT kinases, protected hESC from stress-induced cell death, and increased hESC adhesion and cloning efficiency. This stimulation of self-renewal, cell survival, and adhesion by exogenous and endogenous FGF-2 may synergize to maintain the undifferentiated growth of hESCs.

Disclosure of potential conflicts of interest is found at the end of this article.
A Targeted Neuroglial Reporter Line Generated by Homologous Recombination in Human Embryonic Stem Cells
Authors: Xue Haipeng , Wu Sen , Papadeas Sophia T. , Spusta Steve , Swistowska Anna Maria , MacArthur Chad C. , Mattson Mark P. , Maragakis Nicholas J. , Capecchi Mario R. , Rao Mahendra S. , Zeng Xianmin , Liu Ying
Published: May 2009

In this study, we targeted Olig2, a basic helix-loop-helix transcription factor that plays an important role in motoneuron and oligodendrocyte development, in human embryonic stem cell (hESC) line BG01 by homologous recombination. One allele of Olig2 locus was replaced by a green fluorescent protein (GFP) cassette with a targeting efficiency of 5.7%. Targeted clone R-Olig2 (like the other clones) retained pluripotency, typical hESC morphology, and a normal parental karyotype 46,XY. Most importantly, GFP expression recapitulated endogenous Olig2 expression when R-Olig2 was induced by sonic hedgehog and retinoic acid, and GFP-positive cells could be purified by fluorescence-activated cell sorting. Consistent with previous reports on rodents, early GFP-expressing cells appeared biased to a neuronal fate, whereas late GFP-expressing cells appeared biased to an oligodendrocytic fate. This was corroborated by myoblast coculture, transplantation into the rat spinal cords, and whole genome expression profiling. The present work reports an hESC reporter line generated by homologous recombination targeting a neural lineage-specific gene, which can be differentiated and sorted to obtain pure neural progenitor populations.

Disclosure of potential conflicts of interest is found at the end of this article.
Seismic performance of a 20‐story steel‐frame building in Canada
Authors: Yousuf MD , Bagchi Ashutosh
Published: May 2009

In performance‐based seismic design of a structure, the inelastic deformation demand of structural members or system is the primary input, whereas in conventional design procedure the input is the equivalent static loads to represent seismic effects. The National Building Code of Canada (NBCC) 2005 requires that for irregular and buildings higher than 60 m, dynamic analysis must be conducted to calculate seismic design forces and deflection, while for other cases, equivalent static loads can be used for the design. In this paper, the performance of a 20‐story steel moment resisting steel frame building, designed for western part of Canada, has been presented. Simulated and actual (scaled) ground motion records are used to evaluate the dynamic response. While NBCC does not provide any performance‐based design method, various techniques for displacement‐based design have been explored here in the context of the 20‐story building. A wide range of variation amongst these methods in terms of their application and results was found. Amongst these methods the direct displacement‐based design method seems to be more suitable for carrying out the performance‐based design of a building. Copyright © 2009 John Wiley & Sons, Ltd.
Indoor–outdoor distribution and risk assessment of volatile organic compounds in the atmosphere of industrial and urban areas
Authors: Massolo Laura , Rehwagen Martina , Porta Andres , Ronco Alicia , Herbarth Olf , Mueller Andrea
Published: May 2009

Volatile organic compounds (VOCs), which play an important part indoors and outdoors, comprise differing compound groups such as n‐alkanes, cycloalkanes, aromatic and chlorinated hydrocarbons and terpenes. In the current study, samples were analyzed from indoor (schools and houses, n = 92) and outdoor (n = 33) air in urban, industrial, semirural and residential areas from the region of La Plata (Argentine) to consider VOC exposure in different types of environments. VOCs were sampled for 1 month during winter for 3 years, with passive 3M monitors. Samples were extracted with CS2 and analyzed by GC/MS detectors. The results show significant differences in concentration and distribution between indoor and outdoor samples, depending on the study area. Most VOCs predominantly originated indoors in urban, semirural and residential areas, whereas an important outdoor influence in the industrial area was observed. In all areas alkanes and aromatic compounds dominated, even though a different chemical distribution was seen. Traffic burden was determined as the major source of outdoor VOC with a benzene/toluene ratio close to 0.5. Indoors, C9–C11 alkanes, toluene and xylenes dominated, caused by human activities. In contrast, in the industrial area higher concentrations of hexane, heptane and benzene occurred outdoors and affected the indoor air significantly. The lifetime cancer risk (LCR) associated to the benzene exposure was calculated for children from the different study areas. For all groups the study showed a LCR value greater than 1 × 10−6 related to the benzene exposure indoors as well outdoors. A value two magnitudes higher was detected indoors in the industrial area, what demonstrates the high risk for children living in this area of La Plata. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 339–349, 2010.
Reduced Ternary Rare‐Earth–Transition Metal Tellurides for the Smaller Rare‐Earth Elements. An Exploration and an Explanation of the Marked Stability Differentiation among the Rare‐Earth Elements in These Phases
Authors: Herzmann Nina , Gupta Shalabh , Corbett John D.
Published: May 2009

The existence of further metal‐rich condensed cluster compounds in R–Z–Te systems has been synthetically explored for R = Sc, Y, Pr, Dy, Er, Tm, Yb, Lu and, mainly, Z = Ru, Rh, Pd, Ag, Ir, Pt, Au. Ten new examples of orthorhombic Er7Ni2Te2‐type (Imm2) have been identified and that for Dy7Ir2Te2 has been refined. Seven new examples of other ternary structure types plus X‐ray powder pattern evidence for 14 unknown phases have also been identified. To date the family of ternary R–Z–Te phases appears to be limited to those for R = Sc, Y, and Dy–Lu, a trend that is parallel to but more emphatic than those variations found among parallel cluster halide systems. Stability trends among the halide and especially the telluride series follow the I1 + I2 sums for the R elements well, the larger values of which are considered to reflect better mixing of R and Z valence d orbitals in the more stable phases.