bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses of meta‐[18F]fluorobenzaldehyde and meta‐[18F]fluorobenzylbromide from phenyl(3‐Formylphenyl) iodonium salt precursors
Authors: Basuli Falguni , Wu Haitao , Griffiths Gary L. 
Published: February 2011

Abstract18F‐labeled fluorobenzaldehydes and fluorobenzylbromides are useful synthons for the preparation of positron emission tomography radiopharmaceuticals. Although ortho‐ and para‐[18F]fluorobenzaldehydes can easily be prepared with high yields, the corresponding meta‐derivatives are more problematic. In order to improve the yield of meta‐[18F]fluorobenzaldehyde, we used the corresponding diaryliodonium salt precursors, since diaryliodonium salts had already been used as precursors in the preparations of 18F‐labeled electron‐rich, as well as electron‐deficient, aromatic rings. Diaryliodonium salts with different counter ions [PhIPhCHO]X (X = Cl, Br, OTs, OTf) were synthesized. 18F radiolabeling was performed using different bases at different temperatures in the presence of a radical scavenger, 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO). The best conversion (∼80%) to meta‐[18F]fluorobenzaldehyde was obtained using CsHCO3 base at a reaction temperature of 110°C. To study iodonium salt counter ion effects on radiofluorination, each precursor was separately treated with Cs[18F]F/CsHCO3 in DMF at 110°C for 5 min in the presence of TEMPO. Our observed reactivity order was OTs<Cl<OTf<Br. Meta‐[18F]fluorobenzaldehyde thus obtained was reduced to the corresponding alcohol with aqueous NaBH4 at room temperature and then converted to meta‐[18F]fluorobenzylbromide using triphenylphosphine dibromide. Formation of meta‐[18F]fluorobenzylbromide was confirmed using high‐performance liquid chromatography and the desired product was purified on a silica Sep‐Pak® plus cartridge. Published in 2011 by John Wiley & Sons, Ltd.
Directing dopaminergic fiber growth along a preformed molecular pathway from embryonic ventral mesencephalon transplants in the rat brain
Authors: Jin Y. , Zhang C. , Ziemba K.S. , Goldstein G.A. , Sullivan P.G. , Smith G.M. 
Published: February 2011

AbstractTo identify guidance molecules to promote long‐distance growth of dopaminergic axons from transplanted embryonic ventral mesencephalon (VM) tissue, three pathways were created by expressing green fluorescent protein (GFP), glial cell line‐derived neurotrophic factor (GDNF), or a combination of GDNF/GDNF receptor α1 (GFRα1) along the corpus callosum. To generate the guidance pathway, adenovirus encoding these transcripts was injected at four positions along the corpus callosum. In all groups, GDNF adenovirus was also injected on the right side 2.5 mm from the midline at the desired transplant site. Four days later, a piece of VM tissue from embryonic day 14 rats was injected at the transplant site. All rats also received daily subcutaneous injections of N‐acetyl‐L‐cysteinamide (NACA; 100 μg per rat) as well as chondroitinase ABC at transplant site (10 U/ml, 2 μl). Two weeks after transplantation, the rats were perfused and the brains dissected out. Coronal sections were cut and immunostained with antibody to tyrosine hydroxylase (TH) to identify and count dopaminergic fibers in the corpus callosum. In GFP‐expressing pathways, TH+ fibers grew out of the transplants for a short distance in the corpus callosum. Very few TH+ fibers grew across the midline. However, pathways expressing GDNF supported more TH+ fiber growth across the midline into the contralateral hemisphere. Significantly greater numbers of TH+ fibers grew across the midline in animals expressing a combination of GDNF and GFRα1 in the corpus callosum. These data suggest that expression of GDNF or a combination of GDNF and GFRα1 can support the long‐distance dopaminergic fiber growth from a VM transplant, with the combination having a superior effect. © 2011 Wiley‐Liss, Inc.
Partial XBP1 knockdown does not affect viability of oligodendrocyte precursor cells exposed to new models of hypoxia and ischemia in vitro
Authors: Kraskiewicz Honorata , FitzGerald Una 
Published: February 2011

AbstractThe endoplasmic reticulum (ER) stress signaling pathway has been implicated in tissue injury in several rodent models of brain ischemia. To understand better the effects of ischemia on white matter in particular, we developed several in vitro models of hypoxia and ischemia in oligodendrocyte precursors. For the first time, we present data showing that exposure of rat oligodendrocyte precursor cells (OPCs) to cobalt chloride (CoCl2), antimycin A (AA), or oxygen, glucose and nutrient deprivation (OGND) causes up‐regulation of glucose‐regulated protein 78/B‐cell immunoglobulin‐binding protein (Grp78/BiP), C/EBP homologous binding protein (CHOP), and spliced X‐box‐binding protein 1 (XBP1). To mimic the effects of ischemia, OPCs supplemented with 5% normal growth medium and 95% Hank's balanced salt solution were incubated in a hypoxia chamber set at 0.1% oxygen. Because the toxic effects of AA on OPCs more closely resembled those seen when OPCs were subjected to OGND, we found AA treatment preferable to CoCl2 as an in vitro model. To investigate the role of XBP1 in survival following an ischemic insult, we generated a stable XBP1 knockdown OPC cell line and subjected it to simulated hypoxia or ischemia. Surprisingly, 65% XBP1 knockdown had no effect on viability following chemical treatment or OGND. These data strengthen the case for targeting the ER stress signalling pathway in an effort to develop new early treatments for ischemic stroke patients but at the same time demonstrate that partial knockdown of XBP1 is not sufficient to protect precursor oligodendrocytes from ischemic damage. © 2011 Wiley‐Liss, Inc.
Increased expression of the close homolog of the adhesion molecule l1 in different cell types over time after rat spinal cord contusion
Authors: Wu Junfang , Leung Philberta Y. , Sharp April , Joon Lee Hyun , Wrathall Jean R. 
Published: February 2011

AbstractThe close homolog of the adhesion molecule L1 (CHL1) is important during CNS development, but a study with CHL1 knockout mice showed greater functional recovery after spinal cord injury (SCI) in its absence. We investigated CHL1 expression from 1 to 28 days after clinically relevant contusive SCI in Sprague‐Dawley rats. Western blot analysis showed that CHL1 expression was significantly up‐regulated at day 1 and further increased over 4 weeks after SCI. Immunohistochemistry of tissue sections showed that CHL1 in the intact spinal cord was expressed at low levels. By 1 day and through 4 weeks after SCI, CHL1 became highly expressed in NG2+ cells. Hypertrophic GFAP+ astrocytes also expressed CHL1 by 1 week after injury. The increase in CHL1 protein paralleled that of NG2 in the first week and GFAP between 1 and 4 weeks after injury. At 4 weeks, NG2+/CHL1+ cells and GFAP+/CHL1+ astrocytes were concentrated at the boundary between residual spinal cord tissue and the central lesion. NF200+ spinal cord axons approached but did not penetrate this boundary. In contrast, CHL1+ cells in the central lesion at 1 week and later colabeled with p75 and NG2 and were chronically associated with many NF200+ axons, presumably axons that had sprouted in association with CHL1+ Schwann cells infiltrating the cord after contusion. Thus, our study demonstrates up‐regulation of CHL1 in multiple cell types and locations in a rat model of contusion injury and suggests that this molecule may be involved both in inhibition of axonal regeneration and in recovery processes after SCI. © 2011 Wiley‐Liss, Inc.
Management of recurrent gastrointestinal stromal tumors
Authors: Winer Joshua H. , Raut Chandrajit P. 
Published: February 2011

AbstractRecurrence after resection of primary gastrointestinal stromal tumor (GIST) is an unfortunately all‐too‐common phenomenon. The principal treatment for recurrent GIST is the first‐line tyrosine kinase inhibitor (TKI) imatinib mesylate. Those who progress on, or are intolerant of imatinib, are treated with second‐line TKI sunitinib malate. Cytoreductive surgery may be considered as an “adjuvant” therapy for patients with disease stabilized on imatinib, and, on an individual basis, sunitinib. J. Surg. Oncol. 2011; 104:915–920. © 2011 Wiley Periodicals, Inc.
Recent developments in the HPLC separation of phenolic compounds
Authors: Kalili Kathithileni M. , de Villiers André 
Published: February 2011

AbstractPhenolic compounds represent a class of highly complex naturally occurring molecules that possess a range of beneficial health properties. As a result, considerable attention has been devoted to the analysis of phenolics in a variety of samples. HPLC is the workhorse method for phenolic separation. However, conventional HPLC methods provide insufficient resolving power when faced with the complexity of real‐world phenolic fractions. This limitation has been traditionally circumvented by extensive sample fractionation, multiple analysis methods and/or selective detection strategies. On the other hand, there is an increasing demand for improved throughput and resolving power from the chromatographic methods used for phenolic analyses. Fortunately, during the last decade, a number of important technological advances in LC have demonstrated significant gains in terms of both speed and resolution. These include ultra high‐pressure liquid chromatography (UHPLC), high‐temperature liquid chromatography (HTLC), multi‐dimensional separations as well as various new stationary phase chemistries and morphologies. In recent years, these technologies have also found increasing application for phenolic analysis. This review seeks to provide an updated overview of the application of recent advances in HPLC to phenolic separation, with the emphasis on how these methodologies can contribute to improve performance in HPLC analysis of phenolics.
Surface Modification to Control Protein/Surface Interactions
Authors: Yuan Lin , Yu Qian , Li Dan , Chen Hong 
Published: February 2011

AbstractProtein/surface interactions are well known to play an important role in various biological phenomena and to determine the ultimate biofunctionality of a given material once it is in contact with a biological environment. Control over the interactions between proteins and material surfaces are not only of great theoretical interest but also of crucial importance for many biomedical applications. In this Feature Article, we summarize various successful approaches used in our laboratory and other groups for controlling protein adsorption through chemical modification of the surface and/or the introduction of specific topographic features. Some perspectives on future research in these areas are also presented.
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Engineering geo‐engineering
Authors: Fox Timothy A. , Chapman Lee 
Published: February 2011

AbstractThis paper reviews the geo‐engineering approach to tackling climate change. The failure of the 15th United Nations Framework Convention on Climate Change Conference of the Parties (COP15) to obtain a legally binding emissions reduction agreement makes the deployment of geo‐engineering solutions an increasingly attractive proposition. This review looks at a variety of global and local approaches to geo‐engineering covering solar radiation management and carbon cycle engineering and attempts to assess the feasibility of the technologies from an engineering perspective. However, despite the plethora of ideas generated by the science community, it still appears that much work remains to be done in the initial engineering assessment of these techniques and this is a major hurdle to overcome before any geo‐engineering scheme can be fully considered. Hence, the paper concludes by calling for the instigation of national and international programmes of research at the feasibility level, to inform discussions regarding future possible deployment of small scale, local geo‐engineering and adaptation measures. Copyright © 2011 Royal Meteorological Society
In‐Line Monitoring of Particle Size during Emulsion Polymerization under Different Operational Conditions using NIR Spectroscopy
Authors: Chicoma Dennis L. , Sayer Claudia , Giudici Reinaldo 
Published: February 2011

AbstractIn the present work, the sensitivity of NIR spectroscopy toward the evolution of particle size was studied during emulsion homopolymerization of styrene (Sty) and emulsion copolymerization of vinyl acetate–butyl acrylate conducted in a semibatch stirred tank and a tubular pulsed sieve plate reactor, respectively. All NIR spectra were collected online with a transflectance probe immersed into the reaction medium. The spectral range used for the NIR monitoring was from 9 500 to 13 000 cm−1, where the absorbance of the chemical components present is minimal and the changes in the NIR spectrum can be ascribed to the effects of light scattering by the polymer particles. Off‐line measurements of the average diameter of the polymer particles by DLS were used as reference values for the development of the multivariate NIR calibration models based on partial least squares. Results indicated that, in the spectral range studied, it is possible to monitor the evolution of the average size of the polymer particles during emulsion polymerization reactions. The inclusion of an additional spectral range, from 5 701 to 6 447 cm−1, containing information on absorbances (“chemical information”) in the calibration models was also evaluated.
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Optimization of pulse train presaturation for CEST imaging in clinical scanners
Authors: Schmitt Benjamin , Zaiß Moritz , Zhou Jinyuan , Bachert Peter 
Published: February 2011

AbstractChemical exchange saturation transfer (CEST) imaging depends on the performance of radiofrequency saturation during the experiment. Scanner specifications, in particular limited pulse width and duty‐cycle, and specific absorption rate guidelines restrict the full exploitation of CEST effects in clinical MR systems. The purpose of this study was to optimize techniques for effective pulse train presaturation for CEST imaging in a whole‐body MR scanner. Theoretical analysis and simulations of the spectral properties of radiofrequency pulse trains demonstrated the significance of pulse width τP and interpulse delay τD for effective and selective labeling of a chemically exchanging proton pool. CEST experiments with model solutions, e.g., creatine dissolved in water, showed best performance of pulse trains with τP = τD = 100 msec, regarding minimum direct water saturation in z‐spectra and distinct magnetization transfer ratio asymmetry that can be determined quantitatively. Saturation efficiency of trains of Gaussian‐shaped radiofrequency pulses using this timing was evaluated in MR imagers with field strengths of 1.5, 3, and 7 T. The proposed saturation pulse train does not require hardware modifications, offers low specific absorption rate, and can be used in a standard clinical setup. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Liver stiffness assessment by tagged MRI of cardiac‐induced liver motion
Authors: Chung Sohae , Breton Elodie , Mannelli Lorenzo , Axel Leon 
Published: February 2011

AbstractCirrhosis is an important and growing public health problem, affecting millions of Americans and many more people internationally. A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide therapy. Here, we report a method to use magnetization‐tagged magnetic resonance imaging to measure the cardiac‐induced motion and deformation in the liver, as a means for noninvasively assessing liver stiffness, which is related to fibrosis. The initial results show statistically significant differences between healthy and cirrhotic subjects in the direct comparisons of the maximum displacement (mm), and the maximum (P1) and minimum (P2) two‐dimensional strains, through the cardiac cycle (3.514 ± 0.793, 2.184 ± 0.611; 0.116 ± 0.043, 0.048 ± 0.011; −0.094 ± 0.020, −0.041 ± 0.015; healthy, cirrhosis, respectively; P < 0.005 for all). There are also significant differences in the displacement‐normalized P1 and P2 strains (mm−1) (0.030 ± 0.008, 0.017 ± 0.007; −0.024 ± 0.006, −0.013 ± 0.004; healthy, cirrhosis, respectively; P < 0.005 for all). Therefore, this noninvasive imaging‐based method is a promising means to assess liver stiffness using clinically available imaging tools. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Time resolved contrast enhanced intracranial MRA using a single dose delivered as sequential injections and highly constrained projection reconstruction (HYPR CE)
Authors: Wu Yijing , Johnson Kevin , Kecskemeti Steven R. , Wang Kang , Wieben Oliver , Aagaard‐Kienitz Beverly L. , Rowley Howard , Korosec Frank R. , Mistretta Charles , Turski Patrick 
Published: February 2011

AbstractTime‐resolved contrast‐enhanced magnetic resonance angiography of the brain is challenging due to the need for rapid imaging and high spatial resolution. Moreover, the significant dispersion of the intravenous contrast bolus as it passes through the heart and lungs increases the overlap between arterial and venous structures, regardless of the acquisition speed and reconstruction window. An innovative technique is presented that divides a single dose contrast into two injections. Initially a small volume of contrast material (2–3 mL) is used to acquiring time‐resolved weighting images with a high frame rate (2 frames/s) during the first pass of the contrast agent. The remaining contrast material is used to obtain a high resolution whole brain contrast‐enhanced (CE) magnetic resonance angiography (0.57 × 0.57 × 1 mm3) that is used as the spatial constraint for Local Highly Constrained Projection Reconstruction (HYPR LR) reconstruction. After HYPR reconstruction, the final dynamic images (HYPR CE) have both high temporal and spatial resolution. Furthermore, studies of contrast kinetics demonstrate that the shorter bolus length from the reduced contrast volume used for the first injection significantly improves the arterial and venous separation. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Temporal filtering effects in dynamic parallel MRI
Authors: Blaimer Martin , Ponce Irene P. , Breuer Felix A. , Jakob Peter M. , Griswold Mark A. , Kellman Peter 
Published: February 2011

AbstractAutocalibrated parallel MRI methods such as TSENSE or k‐t SENSE have been presented for dynamic imaging studies as they are able to provide images with high temporal resolution. One key element of these techniques is the temporal averaging of the undersampled raw data to obtain an unaliased image. This image represents the temporal average (also known as direct current, DC) and is used to derive the reconstruction parameters. In this work, we show that aliasing artifacts can be introduced in the DC signal obtained from the undersampled raw data. These artifacts lead to undesired temporal filtering effects when the DC signal is used for coil sensitivity calibration or when the DC signal is subtracted from the raw data. It is demonstrated that the temporal filtering effects can be reduced significantly by filtering the DC signal. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Detection of tumor glutamate metabolism in vivo using 13C magnetic resonance spectroscopy and hyperpolarized [1‐13C]glutamate
Authors: Gallagher Ferdia A. , Kettunen Mikko I. , Day Sam E. , Hu De‐en , Karlsson Magnus , Gisselsson Anna , Lerche Mathilde H. , Brindle Kevin M. 
Published: February 2011

AbstractDynamic nuclear polarization can be used to increase the sensitivity of solution state 13C magnetic resonance spectroscopy by four orders of magnitude. We show here that [1‐13C]glutamate can be polarized to 28%, representing a 35,000‐fold increase in its sensitivity to detection at 9.4 T and 37°C. The metabolism of hyperpolarized glutamate to α‐ketoglutarate, catalyzed by the enzyme alanine transaminase, was detected in vitro in human hepatoma cells (HepG2). Incubation of the cells with sodium pyruvate increased the level of the hyperpolarized label in the α‐ketoglutarate pool, with an associated increase in the apparent rate constant describing flux of hyperpolarized 13C label between glutamate and α‐ketoglutarate. The metabolism of hyperpolarized glutamate was observed in vivo following coadministration of pyruvate in a murine lymphoma model. This represents a new method to probe glutamate metabolism and citric acid cycle activity in vivo; as glutamate is an endogenous molecule, it has the potential to be used in the clinic. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Quantitative tracking of edema, hemorrhage, and microvascular obstruction in subacute myocardial infarction in a porcine model by MRI
Authors: Ghugre Nilesh R. , Ramanan Venkat , Pop Mihaela , Yang Yuesong , Barry Jennifer , Qiang Beiping , Connelly Kim A. , Dick Alexander J. , Wright Graham A. 
Published: February 2011

AbstractPathophysiological responses after acute myocardial infarction include edema, hemorrhage, and microvascular obstruction along with cellular damage. The in vivo evolution of these processes simultaneously throughout infarct healing has not been well characterized. The purpose of our study was to quantitatively monitor the time course of these mechanisms by MRI in a porcine model of myocardial infarction. Ten pigs underwent MRI before coronary occlusion with subgroups studied at day 2 and weeks 1, 2, 4, and 6 post‐infarction. Tissue characterization was performed using quantitative T2 and T2* maps to identify edema and hemorrhage, respectively. Contrast‐enhanced MRI was used for infarct/ microvascular obstruction delineation. Inflammation was reflected by T2 fluctuations, however at day 2, edema and hemorrhage had counter‐acting effects on T2. Hemorrhage (all forms) and mineralization (calcium) could be identified by T2* in the presence of edema. Simultaneous resolution of microvascular obstruction and T2* abnormality suggested that the two phenomenon were closely associated during the healing process. Our study demonstrates that quantitative T2 and T2* mapping techniques allow regional, longitudinal, and cross‐subject comparisons and give insights into histological and tissue remodeling processes. Such in vivo characterization will be important in grading severity and evaluating treatment strategies for myocardial infarction, potentially improving clinical outcomes. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Naivety and relationship marketing in nonprofit organisations
Authors: Catherine  , O'Sullivan Terry 
Published: February 2011

AbstractThe widespread adoption of the language and concepts of marketing as a series of exchanges with customers continues to present problems to nonprofit organisations. Measured against marketing orthodoxy their approach to marketing might appear naive, but it is often effective. This paper discusses five differences between ‘orthodox’ and ‘naive’ marketing (nature of the exchange, focus of the encounter, attitude to technology, attitude to product and plans for the customer) to explore the nature of naive marketing. The role and importance of product or service in nonprofits is emphasised as a crucial difference. Finally, the emerging discipline of relationship marketing is argued to be a framework which vindicates many of the positions of naive marketers and to offer a valuable source of theory for nonprofit marketing.