bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective resonance suppression 1H‐[13C] NMR spectroscopy with asymmetric adiabatic RF pulses
Authors: Xin Lijing , Frenkel Hanne , Mlynárik Vladimír , Morgenthaler Florence D. , Gruetter Rolf
Published: January 2009

Despite obvious improvements in spectral resolution at high magnetic field, the detection of 13C labeling by 1H‐[13C] NMR spectroscopy remains hampered by spectral overlap, such as in the spectral region of 1H resonances bound to C3 of glutamate (Glu) and glutamine (Gln), and C6 of N‐acetylaspartate (NAA). The aim of this study was to develop, implement, and apply a novel 1H‐[13C] NMR spectroscopic editing scheme, dubbed “selective Resonance suppression by Adiabatic Carbon Editing and Decoupling single‐voxel STimulated Echo Acquisition Mode” (RACED‐STEAM). The sequence is based on the application of two asymmetric narrow‐transition‐band adiabatic RF inversion pulses at the resonance frequency of the 13C coupled to the protons that need to be suppressed during the mixing time (TM) period, alternating the inversion band downfield and upfield from the 13C resonance on odd and even scans, respectively, thus suppressing the detection of 1H resonances bound to 13C within the transition band of the inversion pulse. The results demonstrate the efficient suppression of 1H resonances bound to C3 of Glu and Gln, and C4 of Glu, which allows the 1H resonances bound to C6 of NAA and C4 of Gln to be revealed. The measured time course of the resolved labeling into NAA C6 with the new scheme was consistent with the slow turnover of NAA. Magn Reson Med 61:260–266, 2009. © 2009 Wiley‐Liss, Inc.
Use of magnetic nanoparticles to monitor alginate‐encapsulated βTC‐tet cells
Authors: Constantinidis Ioannis , Grant Samuel C. , Simpson Nicholas E. , Oca‐Cossio Jose A. , Sweeney Carol A. , Mao Hui , Blackband Stephen J. , Sambanis Athanassios
Published: January 2009

Noninvasive monitoring of tissue‐engineered constructs is an important component in optimizing construct design and assessing therapeutic efficacy. In recent years, cellular and molecular imaging initiatives have spurred the use of iron oxide‐based contrast agents in the field of NMR imaging. Although their use in medical research has been widespread, their application in tissue engineering has been limited. In this study, the utility of monocrystalline iron oxide nanoparticles (MIONs) as an NMR contrast agent was evaluated for βTC‐tet cells encapsulated within alginate/poly‐L‐lysine/alginate (APA) microbeads. The constructs were labeled with MIONs in two different ways: 1) MION‐labeled βTC‐tet cells were encapsulated in APA beads (i.e., intracellular compartment), and 2) MION particles were suspended in the alginate solution prior to encapsulation so that the alginate matrix was labeled with MIONs instead of the cells (i.e., extracellular compartment). The data show that although the location of cells can be identified within APA beads, cell growth or rearrangement within these constructs cannot be effectively monitored, regardless of the location of MION compartmentalization. The advantages and disadvantages of these techniques and their potential use in tissue engineering are discussed. Magn Reson Med 61:282–290, 2009. © 2009 Wiley‐Liss, Inc.
Temporal stability of adaptive 3D radial MRI using multidimensional golden means
Authors: Chan Rachel W. , Ramsay Elizabeth A. , Cunningham Charles H. , Plewes Donald B.
Published: January 2009

Breast tumor diagnosis requires both high spatial resolution to obtain information about tumor morphology and high temporal resolution to probe the kinetics of contrast uptake. Adaptive sampling of k‐space allows images in dynamic contrast‐enhanced (DCE)‐magnetic resonance imaging (MRI) to be reconstructed at various spatial or temporal resolutions from the same dataset. However, conventional radial approaches have limited flexibility that restricts image reconstruction to predetermined resolutions. Golden‐angle radial k‐space sampling achieves flexibility in‐plane with samples that are incremented by the golden angle, which fills two‐dimensional (2D) k‐space with radial spokes that have a relatively uniform angular distribution for any time interval. We extend this method to three‐dimensional (3D) radial sampling, or 3D‐Projection Reconstruction (3D‐PR) using multidimensional golden means, which are derived from modified Fibonacci sequences by an eigenvalue approach. We quantitatively compare this technique to conventional 3D radial methods in terms of the fluctuation in error caused by undersampling artifacts, and show that the golden 3D‐PR method can substantially improve the temporal stability of quantitative measurements made from dynamic images when compared to conventional 3D radial approaches of k‐space sampling. Magn Reson Med 61:354–363, 2009. © 2009 Wiley‐Liss, Inc.
Reduced power magnetic resonance spectroscopic imaging of the prostate at 4.0 Tesla
Authors: Near Jamie , Romagnoli Cesare , Bartha Robert
Published: January 2009

Proton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been described at 1.5 T and 3 T as a means of localizing prostate cancers with high sensitivity and specificity. This technique could be improved by increasing the field strength further; however, it has not been described in detail above 3 T. To address the increase in B1 and SAR at high field strengths, a new protocol is described for reduced power STEAM MRSI of the prostate at 4.0 Tesla, using a pelvic surface coil array for RF transmission and reception, and a solid, reusable endorectal coil for reception only. The optimal STEAM sequence timing parameters for observation of the strongly coupled citrate spin system were determined through simulation to be echo time (TE) = 27 ms and mixing time (TM) = 27 ms, and the results were verified in vitro. Power reduction was achieved by applying the VERSE method to each of the three slice selective pulses in the STEAM sequence, and the B1max and SAR were reduced by 43% and 36%, respectively. Finally, in vivo spectroscopic imaging data were acquired from a prostate cancer patient, demonstrating the detection of citrate, choline, and creatine with 0.37 cc nominal resolution in a 10 minute scan. Magn Reson Med 61:273–281, 2009. © 2009 Wiley‐Liss, Inc.
Whole‐brain single‐shot STEAM DTI at 4 Tesla utilizing transverse coherences for enhanced SNR
Authors: Stöcker Tony , Kaffanke Joachim , Shah N. Jon
Published: January 2009

Diffusion tensor imaging is an important method for noninvasively acquiring structural information of the human brain. For advanced fiber tracking, the acquisition of diffusion‐weighted (DW) images has to be performed along many different spatial directions, resulting in long scan times. Therefore, the ultra‐fast imaging method, echo‐planar imaging (EPI), is mostly used, but this technique suffers from susceptibility‐induced image artefacts and geometric distortions. These problems become even more pronounced at very high magnetic field strengths. In this regard, DW, single‐shot STEAM is an interesting and rapid imaging alternative to EPI‐based methods. DW single‐shot STEAM enables the acquisition of artefact‐free images albeit at the expense of a reduced signal‐to‐noise ratio (SNR), which can be compensated by utilizing high magnetic fields. Here, the application of DW single‐shot STEAM at 4 Tesla is demonstrated. To optimize the SNR and the resolution properties, a new variable flip‐angle computational algorithm is introduced enabling accurate signal evolution computation with a precise calculation of transverse coherences. Omission of radiofrequency (RF) spoiling results in an approximate twofold increase of the DW signal by integration of the stable refocused transverse magnetization. The advantage of the approach is shown in simulations and in vivo experiments. Magn Reson Med 61:372–380, 2009. © 2009 Wiley‐Liss, Inc.
Comparison of hypercapnia‐based calibration techniques for measurement of cerebral oxygen metabolism with MRI
Authors: Bulte Daniel P. , Drescher Knut , Jezzard Peter
Published: January 2009

MRI may be used to measure fractional changes in cerebral oxygen metabolism via a metabolic model. One step commonly used in this measurement is calibration with image data acquired during hypercapnia, which is a state of increased CO2 content of the blood. In this study some commonly used hypercapnia‐inducing stimuli were compared to assess their suitability for the calibration step. The following stimuli were investigated: (a) inspiration of a mixture of 4% CO2, 21% O2 and balance N2; (b) 30‐s breath holding; and (c) inspiration of a mixture of 4% CO2 and 96% O2 (i.e., carbogen). Measurements of BOLD and cerebral blood flow made on nine subjects during the different hypercapnia‐inducing stimuli showed that each stimulus leads to a different calibration of the model. We argue that of the aforementioned stimuli, inspiration of 4% CO2, 21% O2 and balance N2 should be preferred for the calibration as the other stimuli produce responses that violate assumptions of the metabolic model. Magn Reson Med 61:391–398, 2009. © 2009 Wiley‐Liss, Inc.
Advanced Lung Disease: Quality of Life and Role of Palliative Care
Authors: Gilbert Christopher R. , Smith Cecilia M.
Published: January 2009

Advanced restrictive lung diseases remain a challenge for both the clinician and patient alike. Because there are few available treatment options that prolong survival for patients with diseases such as idiopathic pulmonary fibrosis, improvement in quality of life and palliation of significant symptoms become realistic treatment goals. Several validated instruments that assess quality of life and health‐related quality of life have demonstrated the dramatic impact that lung disease has on patients. Quality‐of‐life assessments of patients with interstitial lung disease have commonly cited respiratory complaints as problematic, but other distressing symptoms often not addressed include fear, social isolation, anxiety, and depression. Not only do respiratory symptoms limit this patient population, but the awareness of decreased independence and ability for social participation also has an impact on the quality of life. Some patients describe a deepened spiritual well‐being during their disease process; however, many patients' mental health suffers with experiences of fear, worry, anxiety, and panic. Many patients express desire for more attention to end‐of‐life issues from their physicians. Fears of worsening symptoms and suffocation exist with an expressed desire by most to die peacefully with symptom control. Interventions to improve quality of life are largely directed at symptom control. Pharmacologic and nonpharmacologic interventions have been helpful in relieving dyspnea. Studies have demonstrated that the use of supplemental oxygen in the face of advancing hypoxemia can have both positive and negative effects on quality of life. Patients using nasal prongs describe feelings of self‐consciousness, embarrassment, and social withdrawal. Pulmonary rehabilitation is recommended, with some studies noting increased quality‐of‐life scores and decreased sensations of dyspnea. Sleep deprivation and poor sleep quality also have a negative impact on quality of life. Recognition and correction of nocturnal hypoxemia and other sleep disturbances should enhance quality of life in patients with restrictive lung disease; however, there is currently no evidence to support this claim. End‐of‐life care needs more attention by clinicians in the decision‐making and preparatory phase. Physicians need to maintain their focus on quality‐of‐life issues as medical management shifts from curative therapies to comfort management therapies. Palliative care and hospice appear to be underused in patients with advanced diseases other than cancer. Because the only curative option for some end‐stage restrictive lung diseases is lung transplantation, if transplantation is not an option, palliation of symptoms and hospice care may offer patients and families the opportunity to die with dignity and comfort. Mt Sinai J Med 76:63–70, © 2009 Mount Sinai School of Medicine
A mesoscopic model for the behaviour of concrete under high confinement
Authors: Dupray F. , Malecot Y. , Daudeville L. , Buzaud E.
Published: January 2009

When impact loaded, concrete is submitted to high triaxial stresses. The experimental response of concrete under quasi‐static triaxial compression is studied using a triaxial press capable of applying a mean pressure greater than 1 GPa on cylindrical samples measuring 7 cm in diameter and 14 cm high. A numerical analysis of these previous experiments is performed herein at a mesoscopic scale. Concrete is modelled as a biphasic material consisting of a mortar (cement paste and fine aggregates) and roughly spherical aggregates (with a diameter exceeding 2 mm) whose characteristics are applied on a regular cubic finite element mesh. A damage‐plasticity model is then used to model the behaviour of mortar. An identification of model parameters on mortar samples and the subsequent comparison between numerical and experimental tests will be presented for hydrostatic and triaxial compression. Copyright © 2009 John Wiley & Sons, Ltd.
Improved radial basis function fluid–structure coupling via efficient localized implementation
Authors: Rendall T. C. S. , Allen C. B.
Published: January 2009

Previous work by the authors has developed a universal interpolation scheme, using radial basis functions (RBFs), which results in a unified formulation for robust fluid–structure interpolation and high‐quality mesh motion. The method has several significant advantages. Primarily, all volume mesh, structural mesh, and flow‐solver‐type dependence is removed entirely, as all operations are performed on totally arbitrary point clouds of any form. Hence, all connectivity requirements are removed from both the coupling and mesh motion problems. Furthermore, only matrix‐vector multiplications are required during unsteady simulation because dependence relations are computed once prior to any simulation and then remain constant. This property means that the method is both perfectly parallel and totally independent from the flow‐solver. However, the full method is expensive, since the dependence matrix between two sets of points is N × N. The fluid–structure coupling behaviour can also be influenced by parameters used in the interpolation. To alleviate these difficulties a more efficient form of the RBF fluid–structure coupling is presented, which also greatly reduces the interpolation parameter influence. A pointwise form of the partition of unity approach is developed that localizes the interpolation, with results presented for static aeroelastic simulations of the Brite‐Euram multi‐disciplinary optimization wing using a very fine mesh containing 58 000 surface points. It is shown that a 58 × reduction in data size is achieved, and equally importantly the interpolation has a much smaller influence on final aeroelastic results. Copyright © 2009 John Wiley & Sons, Ltd.
The numerical solution of the second Painlevé equation
Authors: Dehghan Mehdi , Shakeri Fatemeh
Published: January 2009

The Painlevé equations were discovered by Painlevé, Gambier and their colleagues during studying a nonlinear second‐order ordinary differential equation. The six equations which bear Painlevé's name are irreducible in the sense that their general solutions cannot be expressed in terms of known functions. Painlevé has derived these equations on the sole requirement that their solutions should be free from movable singularities. Many situations in mathematical physics reduce ultimately to Painlevé equations: applications including statistical mechanics, plasma physics, nonlinear waves, quantum gravity, quantum field theory, general relativity, nonlinear optics, and fiber optics. This fact has caused a significant interest to the study of these equations in recent years. In this study, the solution of the second Painlevé equation is investigated by means of Adomian decomposition method, homotopy perturbation method, and Legendre tau method. Then a numerical evaluation and comparison with the results obtained by the method of continuous analytic continuation are included. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Synthesis of surface‐initiated polymer brushes using macro‐initiators
Authors: Edmondson Steve , Armes Steven P
Published: January 2009

The synthesis of polymer brushes using surface‐adsorbed macro‐initiators is briefly reviewed, with particular emphasis being placed on the combination of atom transfer radical polymerisation with polyelectrolytic macro‐initiators. The latter contain 2‐bromoester initiator groups and can be readily prepared with either cationic or anionic character from (co)polymer precursors. Such macro‐initiators offer convenient functionalisation of a wide range of colloidal and planar charged surfaces such as silica, mica, alumina or tin(IV) oxide, since electrostatic adsorption occurs rapidly from aqueous solution at room temperature. A wide range of hydrophilic methacrylic polymer brushes have been grown from these macro‐initiators, offering potential applications in surface lubricity and tribology, tuneable surface (de)wetting and cell detachment. In some cases surface degrafting can occur if thicker polymer brushes are targeted. However, this problem can be circumvented if pairs of oppositely charged polyelectrolytic macro‐initiators are used to build up ionically crosslinked multilayers via layer‐by‐layer self‐assembly. This facile approach to surface functionalisation appears to be steadily growing in popularity and has now been adopted by a number of research groups in several countries. Copyright © 2009 Society of Chemical Industry
Synthesis and properties of sulfonated polyimides derived from bis(sulfophenoxy) benzidines
Authors: Sutou Yoshiki , Yin Yan , Hu Zhaoxia , Chen Shouwen , Kita Hidetoshi , Okamoto Ken‐Ichi , Wang Hongyuan , Kawasato Hironobu
Published: January 2009

A series of aromatic sulfonated polyimides (SPIs) bearing sulfophenoxy side groups have been successfully synthesized and evaluated as polymer electrolyte membranes for fuel cell applications. The SPIs had high viscosity and gave tough and flexible membranes. The SPI membranes showed anisotropic membrane swelling in water with much larger dimensional change in thickness direction than in plane one. They showed the better proton‐conducting performance even in the lower relative humidity (RH) range than the other SPI membranes, for example, a high proton conductivity of 0.05 S/cm at 50 % RH and 120 °C. They maintained high mechanical strength and conductivity after aging in water at 130 °C for 500 h, showing much better water stability compared with the main‐chain‐type SPI and side‐chain‐type SPI membranes reported so far. In polymer electrolyte fuel cells (PEFCs) operated at 90 °C and 84–30%RH, they showed fairly high cell performances and have high potential for PEFC applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1463–1477, 2009
Hydrobromination of residual vinyl groups on divinylbenzene polymer particles followed by atom transfer radical surface graft polymerization
Authors: Limé Fredrik , Irgum Knut
Published: January 2009

Rigid and monodisperse spherical polymer particles with 2.36 ± 0.18 μm diameter containing residual surface vinyl groups were prepared by photoinitiated precipitation polymerization of divinylbenzene. Anti‐Markovnikov addition of HBr to the surface vinyl groups yielded a 2‐bromoethyl functionality that was used as macroinitiator for atom transfer radical polymerization (ATRP), providing the possibility for further functionalization by controlled “grafting from” processes. This was demonstrated by grafting of glycidyl methacrylate brushes from the particle surface, using an ATRP system based on CuBr and pentamethyl diethylenetriamine. Existence of a methacrylic overlayer was verified by FTIR and XPS measurements, and the grafted particles were easily dispersed in water, confirming conversion of the particle surface from hydrophobic to hydrophilic. Hydrobromination of residual vinyl groups yields a macroinitiator that can be used for grafting of glycidyl methacrylate by ATRP. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1259–1265, 2009
Amphiphilic conetworks. IV. Poly(methacrylic acid)‐l‐polyisobutylene and poly(acrylic acid)‐l‐polyisobutylene based hydrogels prepared by two‐step polymer procedure. New pH responsive conetworks
Authors: Toman Ludĕk , Janata Miroslav , Spĕváček Jiří , Brus Jiří , Sikora Antonín , Horský Jiří , Vlček Petr , Látalová Petra
Published: January 2009

This article describes the synthesis and characterization of new amphiphilic polymer conetworks containing hydrophilic poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) and hydrophobic polyisobutylene (PIB) chains. These conetworks were prepared by a two‐step polymer synthesis. In the first step, a cationic copolymer of isobutylene (IB) and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate (IDI) was prepared. The isocyanate groups of the IB–IDI random copolymer were subsequently transformed in situ to methacrylate (MA) groups in reaction with 2‐hydroxyethyl methacrylate (HEMA). In the second step, the resulting MA‐multifunctional PIB‐based crosslinker, PIB(MA)n, with an average functionality of approximately four methacrylic groups per chain, was copolymerized with methacrylic acid (MAA) or acrylic acid (AA) by radical mechanism in tetrahydrofuran giving rise to amphiphilic conetworks containing 31–79 mol % of MAA or 26–36 mol % of AA. The synthesized conetworks were characterized with solid‐state 13C‐NMR spectroscopy and differential scanning calorimetry. The amphiphilic nature of the conetworks was proven by swelling in both aqueous media with low and high pH and n‐heptane. The effect of varying pH on the swelling behavior of the synthesized conetworks is presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1284–1291, 2009
Poly(ether tert‐amine): A novel family of multiresponsive polymer
Authors: Ren Yanrong , Jiang Xuesong , Yin Jie
Published: January 2009

A novel multiresponsive poly(ether tert‐amine) (PEA) was synthesized by nucleophilic addition/ring‐opening reaction of commercial poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and di‐epoxy and di‐amine monomer. The process of synthesis was very simple and green in ethanol as reactive media. These PEAs exhibit sharp response to temperature, pH, and ionic strength, with adjustable and sharp phase transitions in the range of 27–100 °C. The lower critical solution temperature (LCST) of PEA's aqueous solution presents a linear relationship to the PEO content (y = 35.7 + x), indicating well‐tunable LCST. The concentration of PEA has no obvious effect on LCST. Therefore, PEA will be potential in applications of drug delivery, separation, and biotechnology. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1292–1297, 2009
All‐aromatic liquid crystalline thermosets with high glass transition temperatures
Authors: Iqbal Mazhar , Norder Ben , Mendes Eduardo , Dingemans Theo J.
Published: January 2009

We have synthesized and characterized a new family of low melting all‐aromatic ester‐based liquid crystal oligomers end‐capped with reactive phenylethynyl end groups. In a consecutive, high‐temperature step, the reactive end groups were thermally activated and polymerization was initiated. This reactive oligomer approach allows us to synthesize liquid crystal thermosets with outstanding mechanical and thermal properties, which are superior to well‐known high‐performance polymers such as PPS and PEEK. We have modified an intractable LC formulation based on hydroquinone and terephthalic acid, with Mn = 1000, 5000, and 9000 g mol−1, and varied the backbone composition using isophthalic acid, resorcinol, 4‐hydroxy‐benzoic acid, 6‐hydroxy‐2‐naphthoic acid, and chlorohydroquinone. All fully cured polymers showed glass transition temperatures in the range of 164–275 °C, and high storage moduli at room temperature (∼ 5 GPa) and elevated temperature (∼ 2 GPa at 200 °C). All oligomers display nematic mesophases and in most cases, the nematic order is maintained after cure. Rheology experiments showed that the phenylethynyl end group undergoes predominantly chain extension below 340 °C and crosslinking above this temperature. Highly aligned fibers could be spun from the nematic melt, and we found that the order parameter 〈P2〉 was not affected by the chain extension and crosslink chemistry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1368–1380, 2009
Analysis of association constant for ground‐state dye‐electron acceptor complex of photoinitiator systems and the association constant effect on the kinetics of visible‐light‐induced polymerizations
Authors: Kim Dongkwan , Scranton Alec B. , Stansbury Jeffrey W.
Published: January 2009

We investigated the formation of ground‐state donor/acceptor complexes between xanthene dyes [rose bengal (RB) and fluorescein (FL)] and a diphenyliodonium (DPI) salt, which is dissolved in 2‐hydroxyethyl methacrylate (HEMA) monomer. To characterize the association constant of the complex, we have suggested a new analysis model based upon the Benesi–Hildebrand model. Because the assumption of the original Benesi–Hildebrand model is that the absorption bands are only due to the presence of the complex and that the absorption by the free component is negligible, the model cannot be applied to our systems, which is a dye‐based initiator system. For each dye, the molar absorptivity of the ground‐state complex was evaluated as a function of wavelength, and this analysis confirmed the validity of the modified Benesi–Hildebrand model. In addition, we observed that the RB/DPI photoinitiator system failed to produce a perceptible polymerization rate but the FL/DPI photoinitiator system provided high rates of polymerization. On the basis of the association constant for these complexes, we concluded that the observed kinetic differences arise from the different association constant values of the ground‐state dye‐acceptor complex, resulting in back‐electron transfer reaction. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1429–1439, 2009
Synthesis of PEG‐PNIPAM‐PLys hetero‐arm star polymer and its variation of thermo‐responsibility after the formation of polyelectrolyte complex micelles with PAA
Authors: Li Jian , He Wei‐Dong , He Ning , Han Shou‐Chen , Sun Xiao‐Li , Li Li‐Ying , Zhang Bo‐Yu
Published: January 2009

A hetero‐arm star polymer, poly(ethylene glycol)‐poly(N‐isopropylacrylamide)‐poly(L‐lysine) (PEG‐PNIPAM‐PLys), was synthesized by “clicking” the azide group at the junction of PEG‐b‐PNIPAM diblock copolymer with the alkyne end‐group of poly(L‐lysine) (PLys) homopolymer via 1,3‐dipolar cycloaddition. The resultant polymer was characterized by gel permeation chromatography, proton nuclear magnetic resonance, and Fourier transform infrared spectroscopes. Surprisingly, the PNIPAM arm of this hetero‐arm star polymer nearly lose its thermal responsibility. It is found that stable polyelectrolyte complex micelles are formed when mixing the synthesized polymer with poly(acrylic acid) (PAA) in water. The resultant polyelectrolyte complex micelles are core‐shell spheres with the ion‐bonded PLys/PAA chains as core and the PEG and PNIPAM chains as shell. The PNIPAM shell is, as expected, thermally responsive. However, its lower critical solution temperature is shifted to 37.5 °C, presumably because of the existence of hydrophilic components in the micelles. Such star‐like PEG‐PNIPAM‐PLys polymer with different functional arms as well as its complexation with anionic polymers provides an excellent and well‐defined model for the design of nonviral vectors to deliver DNA, RNA, and anionic molecular medicines. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1450–1462, 2009
Formation of the RFX gene regulatory complex induces folding of the interaction domain of RFXAP
Authors: Briggs LaTese , Laird Kholiswa , Boss Jeremy M. , Garvie Colin W.
Published: January 2009

Major histocompatibility complex class II (MHCII) molecules have a central role in the mammalian adaptive immune response against infection. The level of the immune response is directly related to the concentration of MHCII molecules in the cell, which have a central role in initiating the immune response. MHCII molecules are therefore a potential target for the development of immunosuppressant drugs for the treatment of organ transplant rejection and autoimmune disease. The expression of MHCII molecules is regulated by a cell specific multiprotein complex. The RFX complex is the key DNA binding component of this complex. The RFX complex is composed of three proteins—RFX5, RFXAP, and RFXB—all of which are required for activation of expression of the MHCII genes. Little is currently known about the precise regions of the RFX proteins that are required for complex formation, or their structure. We have therefore identified the key regions of RFX5, RFXAP, and RFXB, which are required to form the RFX complex and have characterized the individual domains and the complexes they form using NMR and circular dichroism spectroscopy and isothermal titration calorimetry. Our results support a model for the assembly of the RFX complex in which the interaction between RFX5 and RFXAP promote folding of a poorly structured region ofRFXAP, which is required for high affinity binding of RFXB to the RFX5·RFXAP complex. Proteins 2009. © 2009 Wiley‐Liss, Inc.
REMO: A new protocol to refine full atomic protein models from C‐alpha traces by optimizing hydrogen‐bonding networks
Authors: Li Yunqi , Zhang Yang
Published: January 2009

Protein structure prediction approaches usually perform modeling simulations based on reduced representation of protein structures. For biological utilizations, it is an important step to construct full atomic models from the reduced structure decoys. Most of the current full atomic model reconstruction procedures have defects which either could not completely remove the steric clashes among backbone atoms or generate final atomic models with worse topology similarity relative to the native structures than the reduced models. In this work, we develop a new protocol, called REMO, to generate full atomic protein models by optimizing the hydrogen‐bonding network with basic fragments matched from a newly constructed backbone isomer library of solved protein structures. The algorithm is benchmarked on 230 nonhomologous proteins with reduced structure decoys generated by I‐TASSER simulations. The results show that REMO has a significant ability to remove steric clashes, and meanwhile retains good topology of the reduced model. The hydrogen‐bonding network of the final models is dramatically improved during the procedure. The REMO algorithm has been exploited in the recent CASP8 experiment which demonstrated significant improvements of the I‐TASSER models in both atomic‐level structural refinement and hydrogen‐bonding network construction. Proteins 2009. © 2009 Wiley‐Liss, Inc.
De novoidentification of binding sequences for antibody replacement molecules
Authors: Quirk Stephen , Zhong Shi , Hernandez Rigoberto
Published: January 2009

A newin silicomethod has been developed that automatically identifies peptide sequences that can bind to targets of known three‐dimensional structure. The method is potentially faster and more economical than traditional methods of raising antibodies by means of hybridomas or biopanning technology. The current algorithm creates an initial peptide library that is either completely random or that is constrained by the user. This library represents only a small fraction of possible sequence space and the peptides are created with a specified torsional geometry. The library is used as input to any number of available molecular docking programs and the library is docked and scored. The final rank ordering is then used to create a new library by constraining that library to the sequence conservation pattern deduced from the topN‐scoring peptides in the first round. Successive rounds of screening, scoring, and new library creation ultimately results in the system converging to a final solution set of peptides. To test the method, a family of novel peptides that can bind to, and inhibit the enzyme Deoxyribonuclease I has been discovered. The peptides inhibit the enzyme either alone or when placed into a protein backbone structure as has been confirmed experimentally. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Low glyphosate rates do not affect Citrus limonia (L.) Osbeck seedlings
Authors: Gravena Renan , Victoria Filho Ricardo , Alves Pedro Luis CA , Mazzafera Paulo , Gravena Adriana R
Published: January 2009

BACKGROUND: Glyphosate is used to control weeds in citrus orchards, and accidental spraying or wind drift onto the seedlings may cause growth arrest owing to metabolism disturbance. Two experiments were carried out to investigate the effect of non‐lethal rates (0, 180, 360 and 720 g AI ha−1) of glyphosate on four‐month‐old ‘Cravo’ lime, Citrus limonia (L.) Osbeck, seedlings. Photosynthesis and the concentrations of shikimic acid, total free amino acids and phenolic acids were evaluated.

RESULTS: Only transitory effects were observed in the contents of shikimate and total free amino acids. No visual effects were observed.

CONCLUSION: The present study showed that glyphosate at non‐lethal rates, which is very usual when accidental spraying or wind drift occurs in citrus orchard, did not cause severe metabolic damage in ‘Cravo’ lime seedlings. Copyright © 2009 Society of Chemical Industry
Anisotropy of thermal vibrations and polymorphic transformations in lanthanum and uranium
Authors: Blanter M. S. , Glazkov V. P. , Somenkov V. A.
Published: January 2009

Average thermal atomic displacements along different crystallographic axes were measured for polycrystalline samples employing the method of neutron diffraction and defining the anisotropic Debye–Waller factor, obtained by processing the corresponding reflections. In the double hexagonal close‐packed lanthanum modification, the anisotropy of vibrations is insignificant at room temperature, yet it increases markedly with increasing temperature; also, the relative displacement (in relation to the corresponding lattice parameters) in the basal plane considerably exceeds that along the hexagonal axis. In orthorhombic α‐uranium, large anisotropy is observed even at room temperature, which increases with increasing temperature. It is clearly proved that in lanthanum and uranium the polymorphic transition of low‐temperature anisotropic phases into high‐temperature cubic modifications with isotropic thermal vibrations reduces the maximum relative quantity of thermal displacements at the expense of more homogeneous distribution of vibrations along the lattice axes, and thus probably ‘prevents’ the melting of low‐temperature modifications at a lower temperature due to the critical value of these displacements being reached. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antifungal activity of Glycyrrhiza glabra extracts and its active constituent glabridin
Authors: Fatima Atiya , Gupta Vivek K. , Luqman Suaib , Negi Arvind S. , Kumar J. K. , Shanker Karuna , Saikia Dharmendra , Srivastava Suchita , Darokar M. P. , Khanuja Suman P.S.
Published: January 2009

Glabridin, an active constituent of Glycyrrhiza glabra roots, was found to be active against both yeast and filamentous fungi. Glabridin also showed resistance modifying activity against drug resistant mutants of Candida albicans at a minimum inhibitory concentration of 31.25–250 µg/mL. Although the compound was reported earlier to be active against Candida albicans, but this is the first report of its activity against drug resistant mutants. Copyright © 2009 John Wiley & Sons, Ltd.
The clinical investigation of citrullus colocynthis (L.) schrad fruit in treatment of Type II diabetic patients: a randomized, double blind, placebo‐controlled clinical trial
Authors: Huseini H. Fallah , Darvishzadeh F. , Heshmat R. , Jafariazar Z. , Raza Mohsin , Larijani B.
Published: January 2009

Citrullus colocynthis (L.) Schrad fruit is an herbal medicine used by traditional herbalists for the treatment of diabetes in Iran. To determine its efficacy and toxicity, a 2 month clinical trial was conducted in 50 type II diabetic patients. Two groups of 25 each under standard antidiabetic therapy, received 100 mg C. colocynthis fruit capsules or placebos three times a day, respectively. The patients were visited monthly and glycosylated hemoglobin (HbA1c), fasting blood glucose, total cholesterol, LDL, HDL, triglyceride, aspartate transaminase, alanine transaminase, alkaline phosphatase, urea and creatinine levels were determined at the beginning and after 2 months. The results showed a significant decrease in HbA1c and fasting blood glucose levels in C. colocynthis treated patients. Other serological parameters levels in both the groups did not change significantly. No notable gastrointestinal side effect was observed in either group. In conclusion, C. colocynthis fruit treatment had a beneficial effect on improving the glycemic profile without severe adverse effects in type II diabetic patients. Further clinical studies are recommended to evaluate the long‐term efficacy and toxicity of C. colocynthis in diabetic patients. Copyright © 2009 John Wiley & Sons, Ltd.
Chemical composition and biological potential of plants from the genusBauhinia
Authors: Filho Valdir Cechinel
Published: January 2009

Plants of the genusBauhinia(Fabaceae, Leguminosae), commonly known as cow's‐paw or cow's hoof, are widely distributed in most tropical countries and have been used frequently in folk medicine to treat different kinds of pathologies, particularly diabetes, infections, as well as pain and inflammation. In recent years, interest in these plants has increased considerably throughout the world. The biological properties of different phytopreparations and pure metabolites have been investigated in numerous experimentalin vivoandin vitromodels. Although some contradicting evidence has been documented, in general, the results support the reported therapeutic properties, indicating that they are mainly due to the presence of flavonoids. This review summarizes the recent chemical and biological knowledge of plants of the genusBauhinia. Copyright © 2009 John Wiley & Sons, Ltd.
Pomegranate extract mouth rinsing effects on saliva measures relevant to gingivitis risk
Authors: DiSilvestro Robert A. , DiSilvestro Daniel J. , DiSilvestro David J.
Published: January 2009

Pomegranate components have properties that could promote oral health, including reducing the risk of gingivitis. The present study examined young adults (n = 32, split evenly among both genders), for the effects of 4 weeks of thrice daily mouth rinsing with the pomegranate (Punica granatum L.) extract PomElla® dissolved in water. This treatment changed salivary measures relevant to oral health including gingivitis. The changes were: reduced total protein (which can correlate with plaque forming bacteria readings), reduced activities of aspartate aminotransferase (an indicator of cell injury), reduced alpha‐glucosidase activity (a sucrose degrading enzyme), increased activities of the antioxidant enzyme ceruloplasmin (which could give better protection against oral oxidant stress) and increased radical scavenging capacity (though this increase was significant only by nonparametric statistical analysis). A placebo of cornstarch in water did not affect these measures. These data raise the possibility of using pomegranate extracts in oral health products such as toothpaste and mouthwashes. Copyright © 2009 John Wiley & Sons, Ltd.
Mapping river floodplain ecotopes by segmentation of spectral (CASI) and structural (LiDAR) remote sensing data
Authors: Geerling G. W. , Vreeken‐Buijs M. J. , Jesse P. , Ragas A. M. J. , Smits A. J. M.
Published: January 2009

Floodplain land cover maps are important tools for river management and ecological assessment. These maps have to be revised regularly due to the dynamic nature of floodplains. Automation of the mapping process cuts the map processing time and can increase overall accuracy. Manual delineation and classification of vegetation is based on colour, contrasts (texture) and often‐stereoscopic view of aerial images. In this study, this is mimicked by the simultaneous use of both structural light detection and ranging (LiDAR) and compact airborne spectral imager (CASI) remote sensing data in an image segmentation routine fractal net evolution approach (FNEA). The segmentation results are tested against manually delineated ecotopes. Ecotope delineation improves when LiDAR and CASI are used simultaneously; the combination significantly lowers the number of segmented objects needed to accurately map ecotopes. Overall map accuracy of the LiDAR and CASI combination is 8–19% higher than single CASI and LiDAR, respectively. Copyright © 2009 John Wiley & Sons, Ltd.
Early Beneficial Effects of Bone Marrow-Derived Mesenchymal Stem Cells Overexpressing Akt on Cardiac Metabolism After Myocardial Infarction
Authors: Gnecchi Massimiliano , He Huamei , Melo Luis G. , Noiseux Nicolas , Morello Fulvio , de Boer Rudolf A. , Zhang Lunan , Pratt Richard E. , Dzau Victor J. , Ingwall Joanne S.
Published: January 2009

Administration of mesenchymal stem cells (MSCs) is an effective therapy to repair cardiac damage after myocardial infarction (MI) in experimental models. However, the mechanisms of action still need to be elucidated. Our group has recently suggested that MSCs mediate their therapeutic effects primarily via paracrine cytoprotective action. Furthermore, we have shown that MSCs overexpressing Akt1 (Akt-MSCs) exert even greater cytoprotection than unmodified MSCs. So far, little has been reported on the metabolic characteristics of infarcted hearts treated with stem cells. Here, we hypothesize that Akt-MSC administration may influence the metabolic processes involved in cardiac adaptation and repair after MI. MI was performed in rats randomized in four groups: sham group and animals treated with control MSCs, Akt-MSCs, or phosphate-buffered saline (PBS). High energy metabolism and basal 2-deoxy-glucose (2-DG) uptake were evaluated on isolated hearts using phosphorus-31 nuclear magnetic resonance spectroscopy at 72 hours and 2 weeks after MI. Treatment with Akt-MSCs spared phosphocreatine stores and significantly limited the increase in 2-DG uptake in the residual intact myocardium compared with the PBS- or the MSC-treated animals. Furthermore, Akt-MSC-treated hearts had normal pH, whereas low pH was measured in the PBS and MSC groups. Correlative analysis indicated that functional recovery after MI was inversely related to the rate of 2-DG uptake. We conclude that administration of MSCs overexpressing Akt at the time of infarction results in preservation of normal metabolism and pH in the surviving myocardium.

Disclosure of potential conflicts of interest is found at the end of this article.
Sall4 Is Essential for Stabilization, But Not for Pluripotency, of Embryonic Stem Cells by Repressing Aberrant Trophectoderm Gene Expression
Authors: Yuri Shunsuke , Fujimura Sayoko , Nimura Keisuke , Takeda Naoki , Toyooka Yayoi , Fujimura Yu-Ichi , Aburatani Hiroyuki , Ura Kiyoe , Koseki Haruhiko , Niwa Hitoshi , Nishinakamura Ryuichi
Published: January 2009

Sall4 is a mouse homolog of a causative gene of the autosomal dominant disorder Okihiro syndrome. We previously showed that the absence of Sall4 leads to lethality during peri-implantation and that Sall4-null embryonic stem (ES) cells proliferate poorly with intact pluripotency when cultured on feeder cells. Here, we report that, in the absence of feeder cells, Sall4-null ES cells express the trophectoderm marker Cdx2, but are maintained for a long period in an undifferentiated state with minimally affected Oct3/4 expression. Feeder-free Sall4-null ES cells contribute solely to the inner cell mass and epiblast in vivo, indicating that these cells still retain pluripotency and do not fully commit to the trophectoderm. These phenotypes could arise from derepression of the Cdx2 promoter, which is normally suppressed by Sall4 and the Mi2/NuRD HDAC complex. However, proliferation was impaired and G1 phase prolonged in the absence of Sall4, suggesting another role for Sall4 in cell cycle control. Although Sall1, also a Sall family gene, is known to genetically interact with Sall4 in vivo, Sall1-null ES cells have no apparent defects and no exacerbation is observed in ES cells lacking both Sall1 and Sall4, compared with Sall4-null cells. This suggests a unique role for Sall4 in ES cells. Thus, though Sall4 does not contribute to the central machinery of the pluripotency, it stabilizes ES cells by repressing aberrant trophectoderm gene expression.

Disclosure of potential conflicts of interest is found at the end of this article.
Neurosphere Formation Is an Independent Predictor of Clinical Outcome in Malignant Glioma
Authors: Laks Dan R. , Masterman-Smith Michael , Visnyei Koppany , Angenieux Brigitte , Orozco Nicholas M. , Foran Ian , Yong William H. , Vinters Harry V. , Liau Linda M. , Lazareff Jorge A. , Mischel Paul S. , Cloughesy Timothy F. , Horvath Steve , Kornblum Harley I.
Published: January 2009

Renewable neurosphere formation in culture is a defining characteristic of certain brain tumor initiating cells. This retrospective study was designed to assess the relationship among neurosphere formation in cultured human glioma, tumorigenic capacity, and patient clinical outcome. Tumor samples were cultured in neurosphere conditions from 32 patients with glioma, including a subpopulation of 15 patients with primary glioblastoma. A subsample of renewable neurosphere cultures was xenografted into mouse brain to determine if they were tumorigenic. Our study shows that both renewable neurosphere formation and tumorigenic capacity are significantly associated with clinical outcome measures. Renewable neurosphere formation in cultured human glioma significantly predicted an increased hazard of patient death and more rapid tumor progression. These results pertained to both the full population of glioma and the subpopulation of primary glioblastoma. Similarly, there was a significant hazard of progression for patients whose glioma had tumorigenic capacity. Multivariate analysis demonstrated that neurosphere formation remained a significant predictor of clinical outcome independent of Ki67 proliferation index. In addition, multivariate analysis of neurosphere formation, tumor grade and patient age, demonstrated that neurosphere formation was a robust, independent predictor of glioma tumor progression. Although the lengthy duration of this assay may preclude direct clinical application, these results exemplify how neurosphere culture serves as a clinically relevant model for the study of malignant glioma. Furthermore, this study suggests that the ability to propagate brain tumor stem cells in vitro is associated with clinical outcome.

Disclosure of potential conflicts of interest is found at the end of this article.