bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlling the biodegradation rate of magnesium using biomimetic apatite coating
Authors: Zhang Yajing , Zhang Guozhi , Wei Mei
Published: September 2008

Magnesium is light, biocompatible and has similar mechanical properties to natural bone, so it has the potential to be used as a biodegradable material for orthopedic applications. However, pure magnesium severely corrodes in a physiological environment, which may result in fracture prior to substantial tissue healing. Hydroxyapatite (HA) is the main composition of natural bone. It has excellent bioactivity and osteoconductivity. In this study, HA coating with two different thicknesses was applied onto the surface of pure magnesium substrates using a biomimetic technique. The corrosion rate of the surface‐treated substrates was tested. It was found that both types of coatings substantially slowed down the corrosion of the substrate, and the dual coating was more effective than the single coating in hindering the degradation of the substrate. Thus, the corrosion rate of magnesium implants can be closely tailored by adjusting apatite coating thickness and thereby monitoring the release of magnesium ions into the body. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Sphingosine‐1‐phosphate acts as a developmental stage specific inhibitor of platelet‐derived growth factor‐induced chemotaxis of osteoblasts
Authors: Roelofsen T. , Akkers R. , Beumer W. , Apotheker M. , Steeghs I. , van de Ven J. , Gelderblom C. , Garritsen A. , Dechering K.
Published: September 2008

The development and maintenance of a healthy skeleton depends on the migration of cells to areas of new bone formation. Osteoblasts, the bone forming cells of the body, mature from mesenchymal stem cells under the influence of bone morphogenetic protein. It is unclear at what developmental stage the osteoblasts start to migrate to their functional location. We have studied migration of immature pre‐osteoblasts and of mature osteoblasts in response to Platelet‐derived growth factor (PDGF) and sphingosine‐1‐phosphate (S1P). PDGF is a growth factor involved in bone remodeling and fracture healing whereas S1P is a circulating sphingolipid known to control cell trafficking. Our data indicate that PDGF acts as a chemotactic cue for pre‐osteoblasts. In contrast, S1P is a chemorepellent to these cells. Upon Bone Morphogenetic Protein 2‐induced conversion to the osteoblast phenotype, the chemotaxis response to PDGF is retained whereas the sensitivity to S1P is lost. By RNA interference and overexpression experiments we showed that the expression level of the S1P2 receptor is the sole determinant controlling responsiveness to S1P. The combined data indicate that migration of osteoblasts is controlled by the balance between PDGF, S1P and the differentiation state of the cells. We propose that this mechanism preserves the osteoprogenitor pool in the bone marrow, only allowing the more differentiated cell to travel to sites of bone formation. J. Cell. Biochem. 105: 1128–1138, 2008. © 2008 Wiley‐Liss, Inc.
Role of gender in depressive disorder outcome for individual and group cognitive–behavioral treatment
Authors: Watson Hunna J. , Nathan Paula R.
Published: September 2008

Gender in cognitive–behavioral therapy (CBT) for outcome for depression has been inadequately examined in previous research. Thirty‐five men and 55 women diagnosed with a depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV; American Psychiatric Association, 1994) completed individual CBT at an outpatient community mental health clinic and 56 men and 105 women completed group CBT. Depression severity was measured before treatment and at endpoint using the Beck Depression Inventory‐II (Beck, Steer, & Brown, 1996) along with secondary outcomes of anxiety (Beck Anxiety Inventory; Beck, Epstein, Brown, & Steer, 1988) and quality of life (Quality of Life Enjoyment and Satisfaction Questionnaire; Endicott, Nee, Harrison, & Blumenthal, 1993). Men and women demonstrated equivalent pretreatment and posttreatment illness severity, a comparable gradient of improvement on outcomes, and attainment of clinically meaningful benchmarks. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64:1–15, 2008.
Decay of pavement mortar due to thaumasite formation
Authors: de Rojas M Isabel Sánchez , Sotolongo Reinaldo , Frías Moises , Marín Félix , Rivera Julian , Sabador Elvira
Published: September 2008

BACKGROUND: This paper discusses the formation of thaumasite in the mortar sub‐flooring used as a base material for laying tiles, and the influence of this mineral in relation to deterioration of building materials. An investigation of a mortar sub‐flooring constructed with dolomitic limestone sand with high sulfate content used to settle a ceramic pavement was carried out.

RESULTS: The mortar sub‐flooring underwent an important deterioration process due to the formation of expansive compounds in the environmental conditions of temperature and humidity of the installation area in Murcia (Spain). Expansion appeared essentially at the interface between the ceramic tiles and the mortar sub‐flooring, an area consisting primarily of cement paste.

CONCLUSION: Materials present in the soft pulpy mass were examined by X‐ray diffraction and scanning electron microscopy with energy‐dispersive X‐rays. The presence of thaumasite was detected, which had been formed under conditions of temperature higher than temperatures reported in the literature and with a high degree of humidity. Copyright © 2008 Society of Chemical Industry
Synthesis and stability of S‐(2‐[18F]fluoroethyl)‐L‐homocysteine for potential tumour imaging
Authors: Bourdier Thomas , Fookes Christopher J. R. , Pham Tien Q. , Greguric Ivan , Katsifis Andrew
Published: September 2008

The F‐18 labelled methionine derivative S‐(2‐[18F]fluoroethyl)‐L‐homocysteine ([18F]FEHCys) was prepared by a one‐pot two‐step synthesis via the protected S‐(2‐bromoethyl)‐L‐homocysteine 1 and S‐(2‐chloroethyl)‐L‐homocysteine 2 precursors. The bromoethyl derivative 1 gave higher radiochemical yields (40% at 5 min) at 100°C compared with the chloro‐analogue (22% at 100°C in 30 min). However, [18F]FEHCys was found to be unstable in aqueous systems being transformed to the corresponding hydroxyl derivative within 20 min. Copyright © 2008 John Wiley & Sons, Ltd.
Gas‐phase peptide fragmentation: how understanding the fundamentals provides a springboard to developing new chemistry and novel proteomic tools
Authors: Barlow Christopher K. , O'Hair Richard A. J.
Published: September 2008

This tutorial provides an overview of the evolution of some of the key concepts in the gas‐phase fragmentation of different classes of peptide ions under various conditions [e.g. collision‐induced dissociation (CID) and electron transfer dissociation (ETD)], and then demonstrates how these concepts can be used to develop new methods. For example, an understanding of the role of the mobile proton and neighboring group interactions in the fragmentation reactions of protonated peptides has led to the design of the ‘SELECT’ method. For ETD, a model based on the Landau–Zener theory reveals the role of both thermodynamic and geometric effects in the electron transfer from polyatomic reagent anions to multiply protonated peptides, and this predictive model has facilitiated the design of a new strategy to form ETD reagent anions from precursors generated via ESI. Finally, two promising, emerging areas of gas‐phase ion chemistry of peptides are also described: (1) the design of new gas‐phase radical chemistry to probe peptide structure, and (2) selective cleavage of disulfide bonds of peptides in the gas phase via various physicochemical approaches. Copyright © 2008 John Wiley & Sons, Ltd.
Raman scattering of L‐tryptophan enhanced by surface plasmon of silver nanoparticles: vibrational assignment and structural determination
Authors: Chuang Chi‐Hung , Chen Yit‐Tsong
Published: September 2008

Vibrational bands of L‐tryptophan which was adsorbed on Ag nanoparticles (∼10 nm in diameter) have been investigated in the spectral range of 200–1700 cm−1 using surface‐enhanced Raman scattering (SERS) spectroscopy. Compared with the normal Raman scattering (NRS) of L‐tryptophan in either 0.5 M aqueous solution (NRS‐AS) or solid powder (NRS‐SP), the intensified signals by SERS have made the SERS investigation at a lower molecular concentration (5 × 10−4 M) possible. Ab initio calculations at the B3LYP/6‐311G level have been carried out to predict the optimal structure and vibrational wavenumbers for the zwitterionic form of L‐tryptophan. Facilitated with the theoretical prediction, the observed vibrational modes of L‐tryptophan in the NRS‐AS, NRS‐SP, and SERS spectra have been analyzed. In the spectroscopic observations, there are no significant changes for the vibrational bands of the indole ring in either NRS‐AS, NRS‐SP, or SERS. In contrast, spectral intensities involving the vibrations of carboxylate and amino groups are weak in NRS‐AS and NRS‐SP, but strong in SERS. The intensity enhancement in the SERS spectrum can reach 103–104‐fold magnification. On the basis of spectroscopic analysis, the carboxylate and amino groups of L‐tryptophan are determined to be the preferential terminal groups to attach onto the surfaces of Ag nanoparticles in the SERS measurement. Copyright © 2008 John Wiley & Sons, Ltd.
Sternocleidomastoid muscle interposition to prevent carotid artery blowout
Authors: Pathak K. Alok , Viallet Norbert R. , Nason Richard W.
Published: September 2008

Carotid blow‐out syndrome is the most dreaded complication in head and neck surgical oncology practice This article describes a simple technique of interposition of sternocleidomastoid muscle between pharynx and carotid sheath to isolate the latter from salivary contamination in the event of salivary leak. Authors have used this technique in 83 laryngectomies with excellent results. J. Surg. Oncol. 2008;98:565–566. © 2008 Wiley‐Liss, Inc.
Macromol. Chem. Phys. 19/2008
Authors: Saito Tomonori , Harich Kim C. , Long Timothy E.
Published: September 2008

Cover: The cover image shows the brief reaction scheme of well‐defined low molecular weight liquid polybutadienes via anionic telomerization. As can be seen from the monodisperse peak in the SEC curve (right) and the MALDI‐TOF MS spectrum (left), a controlled reaction temperature and reaction procedure minimizes chain transfer and enables the polymerization to occur in living fashion. Further details can be found in the article by T. Saito, K. C. Harich, and T. E. Long* on page 1983.
Advancing the Solid State Properties of Metallo‐Supramolecular Materials: Poly(ε‐caprolactone) Modified π‐Conjugated Bis(terpyridine)s and their Zn(II) Based Metallo‐Polymers
Authors: Winter Andreas , Friebe Christian , Hager Martin D. , Schubert Ulrich S.
Published: September 2008

A set of rigid π‐conjugated bis(terpyridine) macroligands with poly(ε‐caprolactone) (pCL) on their side chains was synthesized and investigated. The introduced pCL chains gave rise to enhanced processability and film‐forming properties of the materials. Blue photoluminescence with high quantum yields was observed in dilute solution and in the solid state, indicating that intermolecular aggregation of the π‐conjugated systems was effectively suppressed. The macroligands were further used for coordination with zinc(II) ions leading to new metallo‐polymers with high solubility, improved film‐forming behavior and promising photophysical properties with respect to potential OLED applications.

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Novel Biopolymer Structures Synthesized by Dendronization of 6‐Deoxy‐6‐aminopropargyl cellulose
Authors: Pohl Matthias , Heinze Thomas
Published: September 2008

Propargyl cellulose with regioselective functionalization pattern was synthesized by nucleophilic displacement reaction of 6‐O‐toluenesulfonyl ester of cellulose (degree of substitution, DS 0.58) with propargyl amine. The novel 6‐deoxy‐6‐aminopropargyl cellulose provides an excellent starting material for the selective dendronization of cellulose at position 6 via the copper‐catalyzed Huisgen reaction yielding 6‐deoxy‐6‐amino‐(4‐methyl‐[1,2,3‐triazolo]‐1‐propyl‐polyamido amine) cellulose derivatives of first‐ (DS 0.33) and second (DS 0.25) generation, which are soluble in polar aprotic solvents. The novel biopolymer derivatives were characterized by elemental analysis, FT‐IR spectroscopy, and one‐ and two dimensional NMR spectroscopy, showing no side reactions (cross‐linking) or impurities and no conversion at the secondary positions.

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Bioactive Amphiphilic Peptide Derivatives with pH Triggered Morphology and Structure
Authors: Jin Yue , Xu Xiao‐Ding , Chen Chang‐Sheng , Cheng Si‐Xue , Zhang Xian‐Zheng , Zhuo Ren‐Xi
Published: September 2008

A series of bioactive amphiphilic peptide derivatives that contain the RGD (Arg‐Gly‐Asp) sequence have been designed and prepared by the standard solid‐phase peptide synthesis (SPPS) technique. The influence of the molecular structure and pH change on the morphology of the amphiphilic peptide derivatives in aqueous solution is investigated. The results reveal that the amphiphilic peptide derivatives with different molecular structures exhibit different self‐assembly behavior in response to environmental changes. Furthermore, by adjusting the pH, the molecular interactions of amphiphilic peptide derivatives are tuned, which results in a morphology change.

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Performance of a miniature high‐temperature superconducting (HTS) surface coil for in vivo microimaging of the mouse in a standard 1.5T clinical whole‐body scanner
Authors: Poirier‐Quinot Marie , Ginefri Jean‐Christophe , Girard Olivier , Robert Philippe , Darrasse Luc
Published: September 2008

The performance of a 12‐mm high‐temperature superconducting (HTS) surface coil for in vivo microimaging of mice in a standard 1.5T clinical whole‐body scanner was investigated. Systematic evaluation of MR image quality was conducted on saline phantoms with various conductivities to derive the sensitivity improvement brought by the HTS coil compared with a similar room‐temperature copper coil. The observed signal‐to‐noise ratio (SNR) was correlated to the loaded quality factor of the radio frequency (RF) coils and is theoretically validated with respect to the noise contribution of the MR acquisition channel. The expected in vivo SNR gain was then extrapolated for different anatomical sites by monitoring the quality factor in situ during animal imaging experiments. Typical SNR gains of 9.8, 9.8, 5.4, and 11.6 were found for brain, knee, back, and subcutaneous implanted tumors, respectively, over a series of mice. Excellent in vivo image quality was demonstrated in 16 min with native voxels down to (59 μm)3 with an SNR of 20. The HTS coil technology opens the way, for the first time at the current field strength of clinical MR scanners, to spatial resolutions below 10–3 mm3 in living mice, which until now were only accessible to specialized high‐field MR microscopes. Magn Reson Med 60:917–927, 2008. © 2008 Wiley‐Liss, Inc.
Four‐dimensional transcatheter intraarterial perfusion (TRIP)‐MRI for monitoring liver tumor embolization in VX2 rabbits
Authors: Wang Dingxin , Virmani Sumeet , Tang Richard , Szolc‐Kowalska Barbara , Woloschak Gayle , Omary Reed A. , Larson Andrew C.
Published: September 2008

Transcatheter intraarterial perfusion (TRIP)‐MRI is an intraprocedural technique to iteratively monitor liver tumor perfusion changes during transcatheter arterial embolization (TAE) and chemoembolization (TACE). However, previous TRIP‐MRI approaches using two‐dimensional (2D) T1‐weighted saturation‐recovery gradient‐recalled echo (GRE) sequences provided only limited spatial coverage and limited capacity for accurate perfusion quantification. In this preclinical study, a quantitative 4D TRIP‐MRI technique (serial iterative 3D volumetric perfusion imaging) with rigorous radiofrequency (RF) B1 field calibration and dynamic tissue longitudinal relaxation rate R1 measurement is presented for monitoring intraprocedural liver tumor perfusion during TAE. 4D TRIP‐MRI and TAE were performed in five rabbits with eight VX2 liver tumors (N = 8). After B1 calibrated baseline and dynamic R1 quantification, subsequent tissue contrast agent concentration time curves were derived. A single‐input flow‐limited pharmacokinetic model and peak gradient method were applied for perfusion analysis. The perfusion Fρ reduced significantly from pre‐TAE 0.477 (95% confidence interval [CI]: 0.384–0.570) to post‐TAE 0.131 (95% CI: 0.080–0.183 ml/min/ml, P < 0.001). Magn Reson Med 60:970–975, 2008. © 2008 Wiley‐Liss, Inc.
New “multicolor” polypeptide diamagnetic chemical exchange saturation transfer (DIACEST) contrast agents for MRI
Authors: McMahon Michael T. , Gilad Assaf A. , DeLiso Marco A. , Cromer Berman Stacey M. , Bulte Jeff W.M. , van Zijl Peter C.M.
Published: September 2008

An array of 33 prototype polypeptides was examined as putative contrast agents that can be distinguished from each other based on the chemical exchange saturation transfer (CEST) mechanism. These peptides were chosen based on predictions of the chemical exchange rates of exchangeable amide, amine, and hydroxyl protons that produce this contrast, and tested at 11.7T for their CEST suitability. Artificial colors were assigned to particular amino acid units (lysine, arginine, threonine, and serine) based on the separate resonance frequencies of these exchangeable protons. The magnitude of the CEST effect could be fine‐tuned by altering the amino acid sequence, and these three exchangeable groups could be distinguished in an MR phantom based on their different chemical shifts (“colors”). These new diamagnetic CEST (DIACEST) agents possess a wide range of electrostatic charges, compositions, and protein stabilities in vivo, making them potentially suitable for a variety of biological applications such as designing MR reporter genes for imaging cells and distinguishing multiple targets within the same MR image. Magn Reson Med 60:803–812, 2008. © 2008 Wiley‐Liss, Inc.
Altered white matter diffusion anisotropy in normal and preterm infants at term‐equivalent age
Authors: Rose Stephen E. , Hatzigeorgiou Xanthy , Strudwick Mark W. , Durbridge Gail , Davies Peter S.W. , Colditz Paul B.
Published: September 2008

To investigate white matter (WM) development, voxelwise analyses of diffusion tensor MRI (DTMRI) data, acquired from 12 very preterm and 11 preterm infants with gestational ages (GA) ranging from 25 to 29 and 29 to 32 weeks, respectively, and 10 newborn normal term infants were performed. T2 relaxation measures were also generated to assess brain water content. Compared with newborn term infants, very preterm infants were found to possess reduced fractional anisotropy (FA) within the frontal lobe, and a number of anterior and posterior commissural pathways. Preterm infants possessed reduced FA mainly within the posterior regions of the corpus callosum. Unexpectedly, we observed significantly reduced FA and increased T2 within a number of corticospinal projections in the newborn term infants compared to the preterm groups. This finding may reflect increased water concentration and/or a lowering of FA due to the presence of crossing interhemispheric WM projections. These findings indicate that care should be taken when interpreting FA indices without knowledge of the possible effects of water concentration in the newborn infant brain. Magn Reson Med 60:761–767, 2008. © 2008 Wiley‐Liss, Inc.
In vivo quantification of transvascular water exchange during the acute phase of permanent stroke
Authors: Kim Y.R. , Tejima E. , Huang S. , Atochin D.N. , Dai G. , Lo E.H. , Huang P.L. , Bogdanov A. , Rosen B.R.
Published: September 2008

Mechanisms that underlie early ischemic damages to the blood‐brain‐barrier (BBB) are not well understood. This study presents a novel magnetic resonance imaging (MRI) technique using a widely available pulse sequence and a long‐circulating intravascular contrast agent to quantify water movements across the BBB at early stages of stroke progression. We characterized the integrity of the BBB by measuring the flip angle dependence of the water exchange‐affected MRI signal intensity, to generate an efficient quantitative index of vascular permeability (WEI, or water exchange index). We performed in vivo MRI experiments to measure the transvascular WEI immediately after the permanent filament occlusion of the middle cerebral artery of mice (n = 5), in which we monitored changes in blood volume (Vb), apparent diffusion coefficient (ADC), and intra‐/extravascular WEI for 4 hours. Statistically significant elevations (P < 0.05) of WEI in the ischemic tissue were observed as early as 1 hour after ischemic onset. Initial reduction of the apparent blood volume (Vapp) in the infarct cortex was followed by a continuous increase of Vapp over time. Although the measured ADC in the ipsilesional cortex continuously decreased, the abnormally high intra‐/extravascular WEI remained constant at a significantly elevated level, indicating apparent BBB injury at this early stage of stroke. Magn Reson Med 60:813–821, 2008. © 2008 Wiley‐Liss, Inc.
Investigation of optimizing and translating pH‐sensitive pulsed‐chemical exchange saturation transfer (CEST) imaging to a 3T clinical scanner
Authors: Sun Phillip Zhe , Benner Thomas , Kumar Ashok , Sorensen A. Gregory
Published: September 2008

Chemical exchange saturation transfer (CEST) MRI provides a sensitive detection mechanism that allows characterization of dilute labile protons usually undetectable by conventional MRI. Particularly, amide proton transfer (APT) imaging, a variant of CEST MRI, has been shown capable of detecting ischemic acidosis, and may serve as a surrogate metabolic imaging marker. For preclinical CEST imaging, continuous‐wave (CW) radiofrequency (RF) irradiation is often applied so that the steady state CEST contrast can be reached. On clinical scanners, however, specific absorption rate (SAR) limit and hardware preclude the use of CW irradiation, and instead require an irradiation scheme of repetitive RF pulses (pulsed‐CEST imaging). In this work, CW‐ and pulsed‐CEST MRI were systematically compared using a tissue‐like pH phantom on an imager capable of both CW and pulsed RF irradiation schemes. The results showed that the maximally obtainable pulsed‐CEST contrast is approximately 95% of CW‐CEST contrast, and their optimal RF irradiation powers are equal. Moreover, the pulsed‐CEST sequence was translated to a 3 Tesla clinical scanner and detected pH contrast from the labile creatine amine groups (1.9 ppm). Furthermore, pilot endogenous APT imaging of normal human volunteers was demonstrated, warranting future APT MRI of stroke patients to elucidate its diagnostic value. Magn Reson Med 60:834–841, 2008. © 2008 Wiley‐Liss, Inc.
Age dependence of regional proton metabolites T2 relaxation times in the human brain at 3 T
Authors: Kirov Ivan I. , Fleysher Lazar , Fleysher Roman , Patil Vishal , Liu Songtao , Gonen Oded
Published: September 2008

Although recent studies indicate that use of a single global transverse relaxation time, T2, per metabolite is sufficient for better than ±10% quantification precision at intermediate and short echo‐time spectroscopy in young adults, the age‐dependence of this finding is unknown. Consequently, the age effect on regional brain choline (Cho), creatine (Cr), and N‐acetylaspartate (NAA) T2s was examined in four age groups using 3D (four slices, 80 voxels 1 cm3 each) proton MR spectroscopy in an optimized two‐point protocol. Metabolite T2s were estimated in each voxel and in 10 gray and white matter (GM, WM) structures in 20 healthy subjects: four adolescents (13 ± 1 years old), eight young adults (26 ± 1); two middle‐aged (51 ± 6), and six elderly (74 ± 3). The results reveal that T2s in GM (average ± standard error of the mean) of adolescents (NAA: 301 ± 30, Cr: 162 ± 7, Cho: 263 ± 7 ms), young adults (NAA: 269 ± 7, Cr: 156 ± 7, Cho: 226 ± 9 ms), and elderly (NAA: 259 ± 13, Cr: 154 ± 8, Cho: 229 ± 14 ms), were 30%, 16%, and 10% shorter than in WM, yielding mean global T2s of NAA: 343, Cr: 172, and Cho: 248 ms. The elderly NAA, Cr, and Cho T2s were 12%, 6%, and 10% shorter than the adolescents, a change of under 1 ms/year assuming a linear decline with age. Formulae for T2 age‐correction for higher quantification precision are provided. Magn Reson Med 60:790–795, 2008. © 2008 Wiley‐Liss, Inc.
Transient MR elastography (t‐MRE) using ultrasound radiation force: Theory, safety, and initial experiments in vitro
Authors: Souchon Rémi , Salomir Rares , Beuf Olivier , Milot Laurent , Grenier Denis , Lyonnet Denis , Chapelon Jean‐Yves , Rouvière Olivier
Published: September 2008

The purpose of our study was to assess the feasibility of using ultrasound radiation force as a safe vibration source for transient MR elastography (t‐MRE). We present a theoretical framework to predict the phase shift of the complex MRE signal, the temperature elevation due to ultrasound, and safety indicators (ISPPA,ISPTA,MI). Next, we report wave images acquired in porcine liver samples in vitro. MR thermometry was used to estimate the temperature elevation induced by ultrasound. Finally, we discuss the implications of our results with regard to the feasibility of using radiation force for t‐MRE in a clinical setting, and a specific echo‐planar imaging (EPI) MRE sequence is proposed. Magn Reson Med 60:871–881, 2008. © 2008 Wiley‐Liss, Inc.
Estimation of the orientation distribution function from diffusional kurtosis imaging
Authors: Lazar Mariana , Jensen Jens H. , Xuan Liang , Helpern Joseph A.
Published: September 2008

The Orientation Distribution Function (ODF) is used to describe the directionality of multimodal diffusion in regions with complex fiber architecture present in brain and other biological tissues. In this study, an approximation for the ODF of water diffusion from diffusional kurtosis imaging (DKI) is presented. DKI requires only a relatively limited number of diffusion measurements and, for the brain, b values no higher than 2500 s/mm2. The DKI‐based ODF approximation is decomposed into two components representing the Gaussian and non‐Gaussian (NG) diffusion contributions, respectively. Simulations of multiple fiber configurations show that both the total and the NG‐ODF are able to resolve the orientations of the component fibers, with the NG‐ODF being the most sensitive to profiling the fibers' directions. Orientation maps obtained for in vivo brain imaging data demonstrate multiple fiber components in brain regions with complex anatomy. The results appear to be in agreement with known white matter architecture. Magn Reson Med 60:774–781, 2008. © 2008 Wiley‐Liss, Inc.
A phase‐sensitive method of flip angle mapping
Authors: Morrell Glen R.
Published: September 2008

A radiofrequency (RF) excitation scheme is presented in which flip angle is encoded in the phase of the resulting excitation. This excitation is implemented with nonselective hard pulses, and is used to give flip angle maps over three‐dimensional volumes. This phase‐sensitive B1 mapping excitation can be combined with various acquisition methods such as gradient recalled echo (GRE) and echo‐planar (EP) readouts. Imaging time depends primarily on the readout method, and is roughly equivalent to the imaging time of conventional double‐angle techniques for three‐dimensional acquisition. The phase‐sensitive method allows imaging over a much wider range of flip angles than double‐angle methods. Phantom and in vivo results are presented comparing the phase‐sensitive method with the conventional double‐angle method, demonstrating the ability of the phase‐sensitive method to measure a wider range of flip angles than double‐angle methods. Magn Reson Med 60:889–894, 2008. © 2008 Wiley‐Liss, Inc.
Single‐shot 3D GRASE with cylindrical k‐space trajectories
Authors: Ramanna S. , Feinberg D.A.
Published: September 2008

Development of GRASE (gradient‐ and spin‐echo) pulse sequences for single‐shot 3D imaging has been motivated by physiologic studies of the brain. The duration of echo‐planar imaging (EPI) subsequences between RF refocusing pulses in the GRASE sequence is determinant of image distortions and susceptibility artifacts. To reduce these artifacts the regular Cartesian trajectory is modified to a circular trajectory in 2D and a cylindrical trajectory in 3D for reduced echo train time. Incorporation of “fly‐back” trajectories lengthened the time of the subsequences and proportionally increased susceptibility artifact but the unipolar readout gradients eliminate all ghost artifacts. The modified cylindrical trajectory reduced susceptibility artifact and distortion artifact while raising the signal‐to‐noise ratio in both phantom and human brain images. Magn Reson Med 60:976–980, 2008. © 2008 Wiley‐Liss, Inc.
Treatment of peritoneal mesothelioma in pediatric patients
Authors: Cioffredi Leigh‐Anne , Jänne Pasi A. , Jackman David M.
Published: September 2008

Peritoneal mesothelioma is a rare and often aggressive malignancy, mostly affecting asbestos exposed adults. We present four pediatric peritoneal cases treated with a cisplatin‐based doublet regimen, the standard of care in the systemic therapy of adult mesothelioma. Treatment was well tolerated, and three of these patients have achieved long‐term survival. The fathers of three of the patients worked in the construction industry and may have been the source of indirect asbestos exposure. Pediatr Blood Cancer 2009;52:127–129. © 2008 Wiley‐Liss, Inc.
Intermittent oral trimethoprim/sulfamethoxazole on two non‐consecutive days per week is effective as Pneumocystis jiroveci pneumonia prophylaxis in pediatric patients receiving chemotherapy or hematopoietic stem cell transplantation
Authors: Ohata Yasuhisa , Ohta Hideaki , Hashii Yoshiko , Tokimasa Sadao , Ozono Keiichi , Hara Junichi
Published: September 2008

Pneumocystis jiroveci pneumonia (PCP) is a serious complication in patients receiving chemotherapy or hematopoietic stem cell transplantation. Current recommendations for trimethoprim‐sulfamethoxazole (TMP‐SMZ) dosing as PCP prophylaxis in immunocompromised patients are based on either daily dosing or dosing three consecutive days per week. We report our experience of prophylaxis with TMP‐SMZ twice daily on two non‐consecutive days per week in 145 immunocompromised children with hematologic disorders, cancer, or metabolic disorders following chemotherapy or hematopoietic stem cell transplantation. There were no breakthrough cases of PCP. We therefore conclude our prophylaxis regimen is effective against PCP in immunocompromised children. Pediatr Blood Cancer 2009;52:142–144. © 2008 Wiley‐Liss, Inc.
Sentinel node biopsy in pediatric soft tissue sarcomas of extremities
Authors: De Corti Federica , Dall'Igna Patrizia , Bisogno Gianni , Casara Dario , Rossi Carlo Riccardo , Foletto Mirto , Alaggio Rita , Carli Modesto , Cecchetto Giovanni
Published: September 2008

Background

Sentinel Node Biopsy is an established staging technique in many adult malignancies. However, only few reports describe this procedure for the evaluation of regional lymph nodes in childhood and adolescents. Our experience with sentinel node biopsy in soft tissue sarcomas of extremities in children is reported.

Methods

Seventeen children were evaluated with sentinel node biopsy between 2002 and 2007: 11 at initial surgery, 5 at primary re‐excision, 1 at local relapse. The diagnosis was rhabdomyosarcoma in 5 and other soft tissue sarcomas in 12: Ewing/PNET sarcoma 6, epithelioid sarcoma 1, malignant peripheral‐nerve‐sheath tumor 1, undifferentiated sarcoma 1, myxoid liposarcoma 2, adult‐type fibrosarcoma 1. Primary sites included lower limbs (8), upper limbs (9). Mapping of nodes was performed with lymphoscintigraphy plus intra‐operative injections with blue‐dye in 14 cases, with lymphoscintigraphy and intra‐operative injections alone in 2 and 1, respectively.

Results

Of the 17 lymphatic regions (9 axilla, 8 inguinal), 16 were identified with lymphoscintigraphy, 15 by intra‐operative injections. Thirty‐five lymph nodes were removed. Nodes were positive for metastasis in two patients with alveolar rhabdomyosarcoma and undifferentiated sarcoma. There were no complications. No further lymph node metastases were recognized either at diagnosis or during the follow‐up (6–78 months).

Conclusions

Sentinel node biopsy was technically feasible, reliable, and free of complications. It could be an alternative to aggressive or random biopsies for extremity rhabdomyosarcoma and it can contribute to define those non‐rhabdomyosarcoma soft tissue sarcomas that spread to regional nodes. Pediatr Blood Cancer 2009;52:51–54. © 2008 Wiley‐Liss, Inc.
Effect of childhood cancer treatment on fertility markers in adult male long‐term survivors
Authors: van Casteren Niels J. , van der Linden Geert H.M. , Hakvoort‐Cammel Friederike G.A.J. , Hählen Karel , Dohle Gert R. , van den Heuvel‐Eibrink Marry M.
Published: September 2008

Background

Although it is accepted that pediatric cancer treatment harbors a risk of gonadal damage, large cohort studies using up‐to‐date fertility markers are lacking.

Procedure

The aim of our study was to evaluate the gonadal toxicity of childhood cancer treatment using fertility markers. We included 248 adult male long‐term survivors of childhood cancer. Median age at diagnosis: 5 years, median age at follow‐up: 24 years, median follow‐up time 18 years. We evaluated patient characteristics, treatment modalities, testicular size, and endocrinological parameters including Inhibin B, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), and testosterone.

Results

The median value of Inhibin B in the cancer survivor group was 126 ng/L versus 177 ng/L in the control group (P < 0.001). In the survivors, 67% had Inhibin B levels below the normal reference value of 150 ng/L compared with 26% in the control group (P < 0.05). Inhibin B was the most sensitive discriminator between survivors and controls. Significantly decreased Inhibin B levels and increased FSH levels were found in men treated for Hodgkin and non‐Hodgkin lymphoma, acute‐myeloid leukemia, neuroblastoma, and sarcoma as compared to other malignancies. Cumulative dosages of procarbazine and cyclophosphamide were the only independent chemotherapy‐related predictors for decrease of Inhibin B levels and increase of FSH. Age at time of treatment did not influence post‐treatment Inhibin B or FSH levels.

Conclusions

Severe gonadal impairment is a risk in a considerable subgroup of childhood cancer survivors based on current fertility markers like Inhibin B. Males receiving gonadotoxic treatment before puberty are not protected from post treatment gonadal dysfunction. Pediatr Blood Cancer 2009;52:108–112. © 2008 Wiley‐Liss, Inc.
Effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/β‐nucleating agent system
Authors: Lv Zhiping , Hu Caixia , Xue Jianwei , Dou Tao
Published: September 2008

The effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/β‐nucleating agent system was investigated with X‐ray diffractometer (XRD), differential scanning calorimeter (DSC), and polarized light microscope (PLM) in this study. Zeolite 5A has less effect on crystalline phase of PP/β‐nucleating agent than does n‐CaCO3, which is ascribed to the stronger surficial polarity and better dispersibility of zeolite 5A. The data of DSC indicated that the crystallization peak temperature of PP increases by 8.3°C in the presence of zeolite 5A, and n‐CaCO3 increases 5.7°C in PP/TMB‐5 system, relative to pure PP. And the initial crystallization temperature (Tc0) and the relative crystallinity (Xc) of PP is much more dramatically raised in the presence of zeolite 5A than CaCO3. The efficiency of zeolite 5A in reducing the spherulites size of PP was seen clearly from the PLM photographs. The mechanical testing results showed that the flexural strength and impact strength of PP/β‐nucleating agent system increased in the presence of zeolite 5A. POLYM. COMPOS., 2008. © Society of Plastics Engineers
A population survey on the use of 24 common medicinal herbs in Australia
Authors: Zhang Anthony Lin , Story David Frederick , Lin Vivian , Vitetta Luis , Xue Charlie Changli
Published: September 2008

Background

Herbal medicine use is common in Australia but little is known about the use of individual herbs.

Methods

A cross‐sectional population survey conducted in 2007 with a sample of 2526, in the Australian state of Victoria.

Results

Almost a quarter (22.6%, 95% confidence interval (CI): 20.9–24.2%) of survey participants had used at least one medicinal herb in the preceding 12 months. Aloe vera, garlic and green tea were the most popular, each used by about 10% of participants. Health enhancement was the most common reason for herbal medicine use (69.6% of users) but relatively high proportions of users sought relief of specific medical conditions. Over 90% considered their herbal medicine to be very or somewhat helpful. Less than half (46.6%) the users were aware that there were potential risks associated with herbal medicine. Relatively high proportions of female users had taken herbal medicine whilst pregnant (14.4%) and/or whilst breast feeding (10.0%). Over half (50.9%) of herbal medicine users had also used Western medicine for the same medical condition in the 12‐month period. Almost the same proportion (49.9%) had used both forms of medication on the same day. In deciding whether or not to use herbal medicine, the vast majority of survey participants indicated that they would accept the advice of their medical practitioner.

Conclusions

In addition to health enhancement, specific herbs are commonly used to treat a range of medical conditions, without clear evidence of efficacy. Concurrent use of herbal and conventional medicine is relatively common and the majority of herbal medicine users are not aware of potential adverse effects. It appears that medical practitioners could exert significant influence on their patients' decisions about herbal medicine use. Copyright © 2008 John Wiley & Sons, Ltd.
Correlation of the melt rheological properties with the foaming behavior of immiscible blends of poly(2,6‐dimethyl‐1,4‐phenylene ether) and poly(styrene‐co‐acrylonitrile)
Authors: Ruckdäschel Holger , Rausch Julius , Sandler Jan K.W. , Altstädt Volker , Schmalz Holger , Müller Axel H.E.
Published: September 2008

Immiscible blends of poly(2,6‐dimethyl‐1,4‐phenylene ether)/poly(styrene‐co‐acrylonitrile) (PPE/SAN) were batch‐foamed using CO2as a blowing agent as a function of foaming temperature, foaming time, and blend composition. Evaluation of the resulting cellular morphology revealed an enhanced foamability of SAN with PPE contents up to 20 wt% as indicated by a similar volume expansion but a significantly reduced mean cell size. This behavior is related to a heterogeneous nucleation activity by the dispersed PPE phase. A further increasing PPE content, however, leads to increasing foam densities as well as nonuniform foam morphologies. The changes in the foaming behavior can be correlated with the melt rheological properties and the corresponding blend morphology. Shear‐rheological investigations revealed an onset of percolation of the dispersed PPE phase between 20 and 40 wt%, and a transition towards cocontinuity at 60 wt%. The materials response under uniaxial elongational flow, as assessed by Rheotens measurements, revealed an increase in elongational viscosity scaling with the PPE content, similar to the shear data. However, the strain hardening behavior was reduced by increasing PPE contents and, at 20 wt%, the drawability revealed a significant drop‐both phenomena limiting the foamability of polymers. In summary, the present study discusses fundamental aspects of foaming immiscible PPE/SAN blends. POLYM. ENG. SCI., 48:2111–2125, 2008. © 2008 Society of Plastics Engineers
The development and characterization of polymer microinjection molded gratings
Authors: Angelov A.K. , Coulter J.P.
Published: September 2008

Ruled diffraction gratings were fabricated via injection micromolding and characterized via atomic force and scanning‐electron microscopy. A unique aspect of this study was the utilization of commercially available optical grating as the injection molding tooling. After depositing a reflective aluminum (Al) coating with 150 and 250 nm thickness onto the untreated polymer replicas, diffracted power profiles of the polymer gratings were compared with that of the mold. It was found that both the mold and nozzle temperatures, Tmold and Tnoz, respectively, are important parameters influencing the fidelity of replication. Statistical analysis, however, revealed that the cyclic olefin copolymer (COC) replicated well the microtopography of the mold but did not replicate properly (within ∼20 nm) the nanotopography formed by the Al grains. Grain size quantification revealed that the Al coating with 150‐nm thickness had smaller grains than that with the 250‐nm coating. Furthermore, testing of delamination of the reflective coatings revealed good adhesion between the COC and Al interface. Lastly, photoelasticity measurements showed stress levels only around the gate of the molded components, suggesting that COCs are excellent materials for optical applications. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Polydomain model predictions of molecular orientation in isothermal channel flows of thermotropic liquid crystalline polymers
Authors: Fang Jun , Burghardt Wesley R. , Bubeck Robert A.
Published: September 2008

We report process simulations of molecular orientation of liquid crystalline polymers for isothermal channel flows in extrusion. The simulations use a “polydomain” model due to Larson and Doi (Larson and Doi, J. Rheol., 35, 539 (1991)), which is implemented by exploiting a nearly exact analogy with a fiber orientation model that is widely used for analysis of composites processing. Simulation results are compared to experimental data previously obtained using a customized X‐ray capable extrusion die that allows a wide range of channel flow geometries to be explored. Competition between inhomogeneous shear and extension in these kinematically complex flows has a profound effect on the resulting molecular orientation distributions. We find that the Larson–Doi model successfully predicts most aspects of the experimental observations, demonstrating its utility for process modeling. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Spatial heterogeneity of photo‐oxidation and its relation with crack propagation in polyethylene composites
Authors: Yang Rui , Liu Ying , Yu Jian , Zhang Dongqing
Published: September 2008

The evolution of oxidation‐depth profiles and section morphologies of high‐density polyethylene (HDPE) composites during natural weathering have been investigated. Crack formation was found to be in good accordance with the development of the oxidation‐depth profile. For stable composites such as HDPE/talc and HDPE/wollastonite, there was no obvious evidence of oxidation and no cracks appeared in the sections. For easily oxidizable composites such as HDPE filled with sericite, mica, kaolin, or diatomite, the oxidation depth profile increased with increasing exposure time, and cracks in the sections developed accordingly. Furthermore, determination of the molecular weight of the surface layer demonstrated that oxidation of the polyethylene chains caused significant chain scission. Recrystallization of the small molecules thus formed resulted in contraction of the surface layer, and the consequent tension led to the appearance of cracks. The transition region closely linked to the injection‐molding process determined the thickness of the surface‐oxidation layer, and hence the average length of the cracks. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Fine line printed silicon solar cells exceeding 20% efficiency
Authors: Hörteis M. , Glunz S.W.
Published: September 2008

Silicon solar cells with passivated rear side and laser‐fired contacts were produced on float zone material. The front side contacts are built up in two steps, seed and plate. The seed layer is printed using an aerosol jet printer and a silver ink. After firing this seed layer through the silicon nitride layer, the conductive layer is grown by light induced plating. The contact formation is studied on different emitter sheet resistances, 55 Ω/sq, 70 Ω/sq, and on 110 Ω/sq. These emitters are passivated with a PECVD silicon nitride layer which also acts as an anti‐reflection coating. Even on the 110 Ω/sq emitters it was possible to reach a fill factor of 80·1%. The electrical properties i.e., the contact resistance of the front side contacts are studied by transfer length model (TLM) measurements. On a cell area of 4 cm2 and emitter sheet resistance of 110 Ω/sq, a record efficiency of 20·3% was achieved. Excellent open‐circuit voltage (Voc) and short‐circuit current (jsc) values of 661 mV and 38·4 mA/cm2 were obtained due to the low recombination in the 110 Ω/sq emitter and at the passivated rear surface. These results show impressively that it is possible to contact emitter profiles with a very high efficiency potential using optimized printing technologies. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and electroluminescent properties of fluorene‐based copolymers containing electron‐withdrawing thiazole derivatives
Authors: Jung In Hwan , Jung Young Kwan , Lee Jonghee , Park Jong‐Hwa , Woo Han Young , Lee Jeong‐Ik , Chu Hye Yong , Shim Hong‐Ku
Published: September 2008

We synthesized two fluorene‐based copolymers poly[(2,5‐bis(4‐hexylthiophen‐2‐yl)thiazolo[5,4‐day]thiazole‐5,5′‐diyl)‐alt‐(9,9′‐dioctylfluorene‐2,7‐diyl)] (PF‐TTZT), and poly[(5,5′‐bis(4‐hexylthiophen‐2‐yl)‐2,2′‐bithiazole‐5,5′‐diyl)‐alt‐(9,9′‐dioctylfluorene‐2,7‐diyl)] (PF‐TBTT), which contain the electron‐withdrawing moieties, thiazolothiazole, and bithiazole, respectively. Through electrochemical studies, we found that these two polymers exhibit stable reversible oxidation and reduction behaviors. Moreover, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PF‐TBTT are lower than those of PF‐TTZT, and the bandgap of PF‐TBTT is smaller than that of PF‐TTZT. Thus the bithiazole moiety in PF‐TBTT is more electron‐withdrawing than the thiazolothiazole moiety in PF‐TTZT. Light‐emitting devices with indium tin oxide (ITO)/poly(3,4‐ethylene dioxythiophene):poly(styrenesulfonate)(PEDOT)/polymer/bis(2‐methyl‐8‐quinolinato)‐4‐phenylphenolate aluminum (BAlq)/LiF/Al configurations were fabricated. The performance of the PF‐TBTT device was found to be almost three times better than that of the PF‐TTZT device, which is because electron injection from the cathode to PF‐TBTT is much easier than for PF‐TTZT. We also investigated the planarity and frontier orbitals of the electron donor‐acceptor (D‐A) moieties with computational calculations using ab initio Hartree–Fock with the split‐valence 6‐31G* basis set. These calculations show that TBTT has a more nonplanar structure than TTZT and that the bithiazole moiety is more electron‐withdrawing than thiazolothiazole. These calculations are in good agreement with the experimental results. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7148–7161, 2008
Synthesis and study of the thermal crosslinking of bis(m‐aminophenyl) methylphosphine oxide based benzoxazine
Authors: Spontón M. , Larrechi M. S. , Ronda J. C. , Galià M. , Cádiz V.
Published: September 2008

Bis(m‐aminophenyl)methylphosphine oxide based benzoxazine (Bz‐BAMPO) was obtained using a three‐step synthetic method from the aromatic diamine and 2‐hydroxybenzaldehyde as starting materials. The structure and purity of the monomer was confirmed by elemental analysis, FTIR, 1H NMR, 13C NMR and 31P NMR spectra. The curing kinetics of Bz‐BAMPO was investigated by nonisothermal differential scanning calorimetry (DSC) at different heating rates and by FTIR spectroscopy. The isoconversional method was used to evaluate the dependence of the effective activation energy on the extent of conversion. The evolving factor analysis (EFA) method was applied to the spectroscopic FTIR data obtained in monitoring benzoxazine homopolymerizations. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7162–7172, 2008