bluuebunny/crossref_metadata_2025_split huggingface dataset:
Apatite‐coated poly(lactic‐co‐glycolic acid) microspheres as an injectable scaffold for bone tissue engineering
Authors: Kang Sun‐Woong , Yang Hee Seok , Seo Sang‐Woo , Han Dong Keun , Kim Byung‐Soo 
Published: September 2007

AbstractBiodegradable polymer/ceramic composite scaffold could overcome limitations of biodegradable polymers or ceramics for bone regeneration. Injectable scaffold has raised great interest for bone regeneration in vivo, since it allows one for easy filling of irregularly shaped bone defects and implantation of osteogenic cells through minimally invasive surgical procedures The purpose of this study was to determine whether apatite‐coated poly(lactic‐co‐glycolic acid) (PLGA) microspheres could be used as an injectable scaffold to regenerate bone in vivo. Apatite‐coated PLGA microspheres were fabricated by incubating PLGA microspheres in simulated body fluid. The apatite that coated the PLGA microsphere surfaces was similar to apatite in natural bone, as demonstrated by scanning electron microscopy, X‐ray diffraction spectra, energy‐dispersive spectroscopy, and Fourier transformed‐infrared spectroscopy analyses. Rat osteoblasts were mixed with apatite‐coated PLGA microspheres and injected immediately into subcutaneous sites of athymic mice. Osteoblast transplantation with plain PLGA microspheres served as a control. Histological analysis of the implants at 6 weeks with hematoxylin and eosin staining, Masson's trichrome staining, and von Kossa staining revealed much better regeneration of bone in the apatite‐coated PLGA microsphere group than the plain PLGA microsphere group. The new bone formation area and the calcium content of the implants were significantly higher in the apatite‐coated PLGA microsphere group than in the plain PLGA microsphere group. This study demonstrates the feasibility of using apatite‐coated PLGA microspheres as an injectable scaffold for in vivo bone tissue engineering. This scaffold may be useful for bone regeneration through minimally invasive surgical procedures in orthopedic applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Fibrous capsule formation around titanium and copper
Authors: Suska Felicia , Emanuelsson Lena , Johansson Anna , Tengvall Pentti , Thomsen Peter 
Published: September 2007

AbstractPrevious studies suggest that implant material properties influence the quality and quantity of fibrous capsule around the implant. However, the precise relation between material surface chemistry, early inflammatory response, and fibrous subsequent repair outcome is still unknown. Titanium (Ti) and copper (Cu), surfaces with different inflammatory potential, were implanted subcutaneously in rats and retrieved fibrous capsules were analyzed after 28 and 56 days. Histological examinations show pronounced differences in capsule morphology. The fibrous capsule around Ti was thinner than that around Cu, with less number of the inflammatory cells in the layer close to the implant surface, and less and smaller blood vessels. The capsule around Cu was thick, with a large number of the inflammatory cells, particularly macrophages and giant cells, and increased number of blood vessels. Our study suggests that material surface properties, which initiate early, multiple cellular inflammatory events, are also associated with increased fibrosis and angiogenesis during repair phase. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Non‐conventional signal transduction by type 1 interferons: The NF‐κB pathway
Authors: Du Ziyun , Wei Lai , Murti Aruna , Pfeffer Susan R. , Fan Meiyun , Yang Chuan He , Pfeffer Lawrence M. 
Published: October 2007

AbstractType I interferons (IFNs) regulate diverse cellular functions by modulating the expression of IFN‐stimulated genes (ISGs) through the activation of the well established signal transduction pathway of the Janus Kinase (JAK) and signal transducers and activators of transcription (STAT) proteins. Although the JAK–STAT signal transduction pathway is critical in mediating IFN's antiviral and antiproliferative activities, other signaling pathways are activated by IFNs and regulate cellular response to IFN. The NF‐κB transcription factor regulates the expression of genes involved in cell survival and immune responses. We have identified a novel IFN mediated signal pathway that leads to NF‐κB activation and demonstrate that a subset of ISGs that play key roles in cellular response to IFN is regulated by NF‐κB. This review focuses on the IFN‐induced NF‐κB activation pathway and the role of NF‐κB in ISG expression, antiviral activity and apoptosis, and the therapeutic application of IFN in cancer and infectious disease. J. Cell. Biochem. 102: 1087–1094, 2007. © 2007 Wiley‐Liss, Inc.
Generation of novel, secreted epidermal growth factor receptor (EGFR/ErbB1) isoforms via metalloprotease‐dependent ectodomain shedding and exosome secretion
Authors: Sanderson Michael P. , Keller Sascha , Alonso Angel , Riedle Svenja , Dempsey Peter J. , Altevogt Peter 
Published: October 2007

AbstractExosomes are small membrane vesicles derived from intracellular multivescicular bodies (MVBs) that can undergo constitutive and regulated secretion from cells. Exosomes can also secrete soluble proteins through metalloprotease‐dependent ectodomain shedding. In this study, we sought to determine whether ErbB1 receptors are present within exosomes isolated from the human keratinocyte cell line, HaCaT, and whether exosome‐associated ErbB1 receptors can undergo further proteolytic processing. We show that full‐length transmembrane ErbB1 is secreted in HaCaT exosomes. EGF treatment and calcium flux stimulated the release of phosphorylated ErbB1 in exosomes but only ligand‐stimulated release was blocked by the ErbB1 kinase inhibitor, AG1478, indicating that ligand‐dependent ErbB1 receptor activation can initiate ErbB1 secretion into exosomes. In addition, other immunoreactive but truncated ErbB1 isoforms were detected in exosomes suggestive of additional proteolytic processing. We demonstrate that cellular and exosomal ErbB1 receptors can undergo ectodomain shedding to generate soluble N‐terminal ectodomains and membrane‐associated C‐terminal remnant fragments (CTFs). ErbB1 shedding was activated by calcium flux and the metalloprotease activator APMA (4‐aminophenylmercuric acetate) and was blocked by a metalloprotease inhibitor (GM6001). Soluble ErbB1 ectodomains shed into conditioned medium retained the ability to bind exogenous ligand. Our results provide new insights into the proteolysis, trafficking and fate of ErbB1 receptors and suggest that the novel ErbB1 isoforms may have functions distinct from the plasma membrane receptor. J. Cell. Biochem. 103: 1783–1797, 2007. © 2007 Wiley‐Liss, Inc.
Trifluoromethanesulfonic acid, an alternative solvent medium for the direct electrophilic fluorination of DOPA: new syntheses of 6‐[18F]fluoro‐L‐DOPA and 6‐[18F]fluoro‐D‐DOPA
Authors: Behnam Azad Babak , Chirakal Raman , Schrobilgen Gary J. 
Published: October 2007

AbstractPrevious work from this laboratory has shown that the direct fluorination of 3, 4‐dihydroxy‐phenyl‐L‐alanine (L‐DOPA) in anhydrous HF (aHF) or BF3/HF with F2 is an efficient method for the synthesis of 6‐fluoro‐L‐DOPA. Since then, 18F‐labeled 6‐fluoro‐L‐DOPA ([18F]6‐fluoro‐L‐DOPA) has been used to study presynaptic dopaminergic function in the human brain and to monitor gastrointestinal carcinoid tumors.This work demonstrates that the reactivity and selectivity of F2 toward L‐DOPA in CF3SO3H is comparable with that in aHF. This new synthetic procedure has led to the production of [18F]fluoro‐L‐DOPA and [18F]fluoro‐D‐DOPA isomers in 17±2% radiochemical yields (decay corrected with respect to [18F]F2). The 2‐ and 6‐FDOPA isomers were separated by HPLC and subsequently characterized by 19F NMR spectroscopy. The corresponding [18F]‐FDOPA enantiomers have been obtained in clinically useful quantities by a synthetic approach that avoids the use of aHF. Copyright © 2007 John Wiley & Sons, Ltd.
A compact one‐dimensional modal FDTD method
Authors: Luo Shuiping , Chen Zhizhang (David) 
Published: September 2007

AbstractThe finite‐difference time‐domain (FDTD) method is an effective technique for computing wideband electrical parameters such as scattering parameters of waveguide structures. in the computations, a known incident is normally required and is usually obtained with a simulation of a long uniform structure. For a three‐dimensional problem, simulation of a long structure can be very memory‐ and CPU time‐intensive. In addition, effective absorbing boundary conditions are needed to effectively terminate the structure even at and below the cutoff frequencies. To address these issues, many one‐dimensional FDTD methods and absorbing schemes were proposed. However, they all have dispersion characteristics different from those of the conventional FDTD method, leading to undesired errors or reflections. In this paper, a new one‐dimensional scheme is developed that has numerical dispersion characteristics very similar to that of the conventional FDTD method. When used as the absorbing boundary condition, it generates reflections of less than −200 dB even at and below the cutoff frequencies for the considered modes. When used to obtain the incident wave, its results have difference of less than −200 dB from that produced by the conventional FDTD method. Copyright © 2007 John Wiley & Sons, Ltd.
Raman scattering from double‐walled carbon nanotubes
Authors: Kuzmany H. , Plank W. , Pfeiffer R. , Simon F. 
Published: September 2007

AbstractRaman scattering from double‐walled carbon nanotubes is reported with particular emphasis on the response from the radial breathing mode (RBM) of the inner‐shell tubes. The unexpected large number of very narrow lines observed is explained by the growth of one and the same inner tube type in different outer tubes in a highly shielded environment. The response of the RBM and of the G‐line is used to analyze the transition from peapods to double‐walled carbon nanotubes. During the transformation process the Raman response disappears for a short time, indicating the existence of some Raman dark matter. By preparing the starting peapods from heterofullerenes such as (C59N)2 or 13C‐substituted fullerenes, hetero‐nanotubes can be grown where nitrogen or the 13C atoms are incorporated into the inner tube wall. Copyright © 2007 John Wiley & Sons, Ltd.
Vibrational spectroscopy of the seselin crystal
Authors: Bento R. R. F. , Freire P. T. C. , Lemos V. , Teixeira A. M. R. , Lima R. J. C. , de Oliveira M. C. F. , Mafezoli J. , Mourão G. M. M. S. , Pontes F. M. 
Published: September 2007

AbstractSeselin, C14H12O3, is a coumarin which crystallizes in a monoclinic structure P21/b(C2h5) with four molecules per unit cell. In a Fourier‐transform Raman spectroscopic study performed at room temperature, several normal modes were observed. Vibrational wavenumber and wave vector calculations using density functional theory were compared with experiment, which allowed the assignment of a number of normal modes of the crystal. Temperature‐dependent Raman spectra were recorded between 10 and 300 K. No anomalies were observed in the phonon spectra, indicating that the monoclinic structure remains stable. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopy of smithsonite
Authors: Frost Ray L. , Hales Matt C. , Wain Daria L. 
Published: September 2007

AbstractRaman spectroscopy at both 298 and 77 K has been used to study a series of selected natural smithsonites from different origins. An intense sharp band at 1092 cm−1 is assigned to the CO32− symmetric stretching vibration. Impurities of hydrozincite are identified by a band around 1060 cm−1. An additional band at 1088 cm−1 which is observed in the 298 K spectra but not in the 77 K spectra is attributed to a CO32− hot band. Raman spectra of smithsonite show a single band in the 1405–1409 cm−1 range assigned to the ν3 (CO3)2− antisymmetric stretching mode. The observation of additional bands for the ν3g modes for some smithsonites is significant in that it shows distortion of the ZnO6 octahedron. No ν2 bending modes are observed for smithsonite. A single band at 730 cm−1 is assigned to the ν4 in phase bending mode. Multiple bands be attributed to the structural distortion are observed for the carbonate ν4 in phase bending modes in the Raman spectrum of hydrozincite with bands at 733, 707 and 636 cm−1. An intense band at 304 cm−1 is attributed to the ZnO symmetric stretching vibration. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of pre‐harvest salicylic acid spray treatment on post‐harvest antioxidant in the pulp and peel of ‘Cara cara’ navel orange (Citrus sinenisis L. Osbeck)
Authors: Huang Renhua , Xia Renxue , Lu Yunmei , Hu Liming , Xu Yongjie 
Published: October 2007

AbstractBACKGROUND: Exogenous salicylic acid (SA) pretreatment could change the antioxidant system and maintain the nutritional value of fruits and vegetables, which have a higher ability to withstand oxidation injuries. However, the relationship between a pre‐harvest SA spray and post‐harvest antioxidant compounds in fruit remains unknown.RESULTS: The post‐harvest behaviour of antioxidant compounds in ‘Cara cara’ navel orange (Citrus sinenisis L. Osbeck) fruit was investigated in relation to the pre‐harvest SA applications. Pre‐harvest SA treatment significantly increased the content of carotenoids (lycopene and α‐carotene), ascorbic acid, glutathione, total phenolics, and total flavonoids in the pulp and peel during storage. Furthermore, the values of these antioxidant compounds were high in the fruit treated with high SA concentrations (1.0 and 2.0 mmol L−1). High antioxidant activity was also observed in the SA pre‐harvest treated fruit when compared with the control. The positive relationships were found between the antioxidant activity and the content of these active compounds.CONCLUSION: These results indicated that SA could maintain fruit antioxidant activity and nutrition which was shown by the increase in content of antioxidant compounds and suggested that pre‐harvest treatment with SA promised a novel technology, which was a substitute for the perplexing programme control of post‐harvest nutrition in fruit. Copyright © 2007 Society of Chemical Industry
Enzymatic modification as a tool to improve the functional properties of heat‐processed soy flour
Authors: Radha Cheruppanpullil , Ramesh Kumar Parigi , Prakash Vishweshwaraiah 
Published: October 2007

AbstractBACKGROUND: There are a number of antinutritional factors present in soybeans that exert a negative impact on the nutritional quality of the protein. Among those factors that are destroyed by heat treatment are protease inhibitors and lectins. Protease inhibitors show antinutritional effect and moreover the digestibility of the protein is limited by the presence of these antinutrients. The aims of the present study are (1) to study the effect of autoclaving on the trypsin inhibitor inactivation, nitrogen solubility and protein digestibility of defatted soy flour and (2) to study the effect of enzymatic modification on the functional properties of autoclaved soy flour.RESULTS: The solubility of the soy flour decreased with increase in autoclaving time. Partial hydrolysis of the autoclaved soy flour increased its acid solubility (pH 4.5) from 17% to 56% over a control value of 24% without affecting its functional properties. Inactivation of trypsin inhibitors improved the protein digestibility of soy flour from 25% to 95%. Particle size analysis of the autoclaved flour indicated the formation of soy protein aggregates, which resulted in poor solubility. The enzymatic modification of autoclaved soy flour resulted in its property as a good emulsifying agent with an emulsion capacity of 118 ± 4 mL.CONCLUSION: Enzymatic modification of the heat‐processed soy flour increased its solubility and other functional attributes. The increased acid solubility would be advantageous in the utilization of soy proteins in acidic foods. Thus the autoclaved and partially modified soy flour is a potential source for specific functional foods. Copyright © 2007 Society of Chemical Industry
The universal covering homomorphism in o‐minimal expansions of groups
Authors: Edmundo Mário J. , Eleftheriou Pantelis E. 
Published: September 2007

AbstractSuppose G is a definably connected, definable group in an o‐minimal expansion of an ordered group. We show that the o‐minimal universal covering homomorphism $ \tilde p $: $ \tilde G $→ G is a locally definable covering homomorphism and π1(G) is isomorphic to the o‐minimal fundamental group π (G) of G defined using locally definable covering homomorphisms. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A ratio‐dependent predator–prey model with stage structure and optimal harvesting policy
Authors: Cai Liming , Li Xuezhi , Yu Jingyuan , Zhu Guangtian 
Published: October 2007

AbstractIn this paper, a ratio‐dependent predator–prey model with stage structure and harvesting is investigated. Mathematical analyses of the model equations with regard to boundedness of solutions, nature of equilibria, permanence and stability are performed. By constructing appropriate Lyapunov functions, a set of easily verifiable sufficient conditions are obtained for the global asymptotic stability of nonnegative equilibria of the model. The existence possibilities of bioeconomic equilibria have been examined. An optimal harvesting policy is also given by using Pontryagin's maximal principle. Copyright © 2007 John Wiley & Sons, Ltd.
Enhanced relative BOLD signal changes in T2‐weighted stimulated echoes
Authors: Goerke Ute , van de Moortele Pierre‐Francois , Ugurbil Kamil 
Published: September 2007

AbstractThe origin of the stimulus/task‐induced signal changes in spin echo (SE) functional MRI (fMRI) at high magnetic fields is dynamic averaging due to diffusion in the presence of field gradients surrounding deoxyhemoglobin‐containing microvasculature. The same mechanism is expected to be operative in stimulated echoes (STE). Compared to SE‐fMRI, however, STE‐fMRI has the potential for larger diffusion weighting and consequently larger stimulus/task‐induced signal changes as a result of an additional delay, the mixing time, TM. In the present study, functional signal changes were quantified for both primary echo (PRE) and STE as a function of echo and mixing time. The relative blood oxygenation level dependent (BOLD) signal changes in STE were larger than in PRE at the same echo time and increased with both mixing and echo time. The contrast‐to‐noise ratio (CNR) of the STE, however, is close to the CNR of the PRE, indicating an increase of physiological noise with longer mixing times. In addition, the signal attenuation due to diffusion in the presence of magnetic field gradients near blood vessels was modeled using Monte Carlo simulations. They support the hypothesis that the sensitivity of the STE to fluctuations of susceptibility‐induced magnetic field gradients near microvasculature is enhanced as a result of an extended diffusion time. Magn Reson Med 58:754–762, 2007. © 2007 Wiley‐Liss, Inc.
A method for improving the performance of gradient systems for diffusion‐weighted MRI
Authors: Nagy Zoltan , Weiskopf Nikolaus , Alexander Daniel C. , Deichmann Ralf 
Published: September 2007

AbstractThe MR signal is sensitive to diffusion. This effect can be increased by the use of large, balanced bipolar gradients. The gradient systems of MR scanners are calibrated at installation and during regular servicing visits. Because the measured apparent diffusion constant (ADC) depends on the square of the amplitude of the diffusion sensitizing gradients, errors in the gradient calibration are exaggerated. If the error is varying among the different gradient axes, it will affect the estimated degree of anisotropy. To assess the gradient calibration accuracy in a whole‐body MRI scanner, ADC values were calculated for a uniform water phantom along each gradient direction while monitoring the temperature. Knowledge of the temperature allows the expected diffusion constant of water to be calculated independent of the MRI measurement. It was found that the gradient axes (±x, ±y, ±z) were calibrated differently, resulting in offset ADC values. A method is presented to rescale the amplitude of each of the six principal gradient axes within the MR pulse sequence. The scaling factor is the square root of the ratio of the expected and observed diffusion constants. In addition, fiber tracking results in the human brain were noticeably affected by improving the gradient system calibration. Magn Reson Med 58:763–768, 2007. © 2007 Wiley‐Liss, Inc.
Very‐low‐frequency electron paramagnetic resonance (EPR) imaging of nitroxide‐loaded cells
Authors: Kao Joseph P.Y. , Barth Eugene D. , Burks Scott R. , Smithback Philip , Mailer Colin , Ahn Kang‐Hyun , Halpern Howard J. , Rosen Gerald M. 
Published: September 2007

AbstractRecent advances in electron paramagnetic resonance (EPR) imaging have made it possible to image, in real time in vivo, cells that have been labeled with nitroxide spin probes. We previously reported that cells can be loaded to high (millimolar) intracellular concentrations with (2,2,5,5‐tetramethylpyrrolidin‐1‐oxyl‐3‐ylmethyl)amine‐N,N‐diacetic acid by incubation with the corresponding acetoxymethyl (AM) ester. Furthermore, the intracellular lifetime (t1/e) of this nitroxide is 114 min—sufficiently long to permit in vivo imaging studies. In the present study, at a gradient of ∼50 mT/m, we acquire and compare EPR images of a three‐tube phantom, filled with either a 200‐μM solution of the nitroxide, or a suspension of cells preincubated with the nitroxide AM ester. In both cases, 3‐mm resolution images can be acquired with excellent signal‐to‐noise ratios (SNRs). These findings indicate that cells well‐loaded with nitroxide are readily imageable by EPR imaging, and that in vivo tracking studies utilizing such cells should be feasible. Magn Reson Med 58:850–854, 2007. © 2007 Wiley‐Liss, Inc.
Combined functional and viability cardiac MR imaging in a single breathhold
Authors: Ibrahim El‐Sayed H. , Stuber Matthias , Kraitchman Dara L. , Weiss Robert G. , Osman Nael F. 
Published: September 2007

AbstractThe combination of cardiac viability and functional information enhances the identification of different heart tissues in the setting of ischemic heart disease. A method has recently been proposed for obtaining black‐blood delayed‐enhancement (DE) viability images using the stimulated‐echo acquisition mode (STEAM) MRI pulse sequence in a single short breathhold. The method was validated against conventional inversion‐recovery (IR) DE images for identifying regions of myocardial infarction (MI). The method was based on the acquisition of three consecutive images of the same anatomical slice. One image has T1‐weighted contrast in which infarction appears bright. The two other images are used to construct an anatomical image of the heart, which is combined with the first image to produce a black‐blood viability image. However, using appropriate modulation and demodulation frequencies, the latter two images bear useful information about myocardial deformation that results in a cardiac strain‐encoding (SENC) functional image. In this work, a method is proposed for obtaining three consecutive SENC images in a single acquisition that can be combined to produce a composite image of the heart, which shows both functional and viability information. The proposed technique reduces scan time by one‐half, compared with separate acquisitions of functional and viability images, and alleviates misregistration problems caused by separate breathholds. Magn Reson Med 58:843–849, 2007. © 2007 Wiley‐Liss, Inc.