bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypoxia/reoxygenation: A dynamic regulator of lysyl oxidase‐facilitated breast cancer migration
Authors: Postovit Lynne‐Marie , Abbott Daniel E. , Payne Stacey L. , Wheaton William W. , Margaryan Naira V. , Sullivan Richard , Jansen Matthias K. , Csiszar Katalin , Hendrix Mary J.C. , Kirschmann Dawn A. 
Published: August 2007

AbstractFluctuating oxygen levels characterize the microenvironment of many cancers and tumor hypoxia is associated with increased invasion and metastatic potential concomitant with a poor prognosis. Similarly, the expression of lysyl oxidase (LOX) in breast cancer facilitates tumor cell migration and is associated with estrogen receptor negative status and reduced patient survival. Here we demonstrate that hypoxia/reoxygenation drives poorly invasive breast cancer cells toward a more aggressive phenotype by up‐regulating LOX expression and catalytic activity. Specifically, hypoxia markedly increased LOX protein expression; however, catalytic activity (β‐aminopropionitrile inhibitable hydrogen peroxide production) was significantly reduced under hypoxic conditions. Moreover, poorly invasive breast cancer cells displayed a marked increase in LOX‐dependent FAK/Src activation and cell migration following hypoxia/reoxygenation, but not in response to hypoxia alone. Furthermore, LOX expression is only partially dependent on hypoxia inducible factor‐1 (HIF‐1α) in poorly invasive breast cancer cells, as hypoxia mimetics and overexpression of HIF‐1α could not up‐regulate LOX expression to the levels observed under hypoxia. Clinically, LOX expression positively correlates with tumor progression and co‐localization with hypoxic regions (defined by HIF‐1α expression) in ductal carcinoma in situ and invasive ductal carcinoma primary tumors. However, positive correlation is lost in metastatic tumors, suggesting that LOX expression is independent of a hypoxic environment at later stages of tumor progression. This work demonstrates that both hypoxia and reoxygenation are necessary for LOX catalytic activity which facilitates breast cancer cell migration through a hydrogen peroxide‐mediated mechanism; thereby illuminating a potentially novel mechanism by which poorly invasive cancer cells can obtain metastatic competency. J. Cell. Biochem. 103: 1369–1378, 2008. © 2007 Wiley‐Liss, Inc.
Optimization of pullulan production using Ca‐alginate‐immobilized Aureobasidium pullulans by response surface methodology
Authors: Ürküt Zümrüt , Daǧbaǧlı Seval , Göksungur Yekta 
Published: August 2007

AbstractBACKGROUND: The production of pullulan from synthetic medium by Aureobasidium pullulans P56 immobilized in Ca‐alginate beads was investigated using batch and repeated batch fermentation systems.RESULTS: The highest pullulan concentration (19.52 ± 0.37 g dm−3) was obtained with 2.0‐2.4 mm beads prepared from 2% sodium alginate solution. Pullulan production was mainly accomplished by immobilized fungal cells since leaked cells in the fermentation medium comprised 17.4% of the total fungal population at the end of fermentation. The pullulan proportion was 84.5% of the total polysaccharide in the fermentation medium. Response surface methodology was used to investigate the effects of three fermentation parameters (initial pH, agitation speed and incubation time) on the concentration of pullulan. Results of the statistical analysis showed that the fit of the model was good in all cases. The maximum pullulan concentration of 21.07 ± 0.48 g dm−3 was obtained at the optimum concentrations of process variables (pH 7.31, agitation speed 191.5 rpm, incubation time 101.2 h). The gel beads produced pullulan under the optimized conditions for six consecutive batch fermentations without marked activity loss and deformation.CONCLUSION: The results of this study suggest that the immobilization of A. pullulans cells in Ca‐alginate gel beads is suitable for batch and repeated batch production of pullulan. Copyright © 2007 Society of Chemical Industry
Sonographic detection of subcutaneous fly larvae in human myiasis
Authors: Richter Joachim , Schmitt Marcus , Müller‐Stöver Irmela , Göbels Klaus , Häussinger Dieter 
Published: August 2007

AbstractSonographers increasingly face imported diseases such as subcutaneous myiasis. In myiasis, some fly species such as the American Dermatobia hominis and the African Cordylobia anthropophaga use humans as intermediate hosts for the maturation of their larvae. High‐resolution gray‐scale and color Doppler sonography enabled us to identify D hominis larvae in 2 travelers to Central America by visualizing their typical shape, segmentations, and the continuous fluid transport inside the larval body cavity and spiracles. The small C anthropophaga larva in an individual returning from Namibia was initially not detected. Only when using color Doppler sonography was the larva discerned by its intralarval fluid transport. Sonography enables clinicians to locate viable subcutaneous larvae in suspected cases of myiasis. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Neuro MR: Principles
Authors: Roberts Timothy P.L. , Mikulis David 
Published: August 2007

AbstractThe principles of contrast mechanisms and fast pulse sequences underlying neurological and neuroradiological application of MRI are introduced in this part of a two‐part review. In particular, the relaxation time constants T1, T2, and T are introduced, along with pulse sequences harnessing their contrast, spin‐echo, fast spin echo (FSE), inversion recovery (IR), gradient recalled echo (GRE), and echo planar imaging (EPI). The use of gadolinium (Gd)‐based contrast is discussed in both T1‐ and T‐weighted sequences. Tradeoffs between speed and image quality are discussed, particularly in the context of long echo train sequences (FSE imaging and EPI). The influence of parallel imaging strategies is also discussed. T sensitivity is discussed as both a source of artifact as well as a contrast mechanism (perfusion imaging with contrast agents, susceptibility weighted imaging [SWI], and blood oxygenation level dependent [BOLD] imaging). Finally, the contrast mechanism of diffusion is introduced, as well as the concept of anisotropy. From these principles, the other part of this two‐part review draws upon the pulse sequences and contrast mechanisms to design disease and indication‐specific protocols for state‐of‐the‐art clinical use. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Microstructural changes in ischemic cortical gray matter predicted by a model of diffusion‐weighted MRI
Authors: Vestergaard‐Poulsen Peter , Hansen Brian , Østergaard Leif , Jakobsen Rikke 
Published: August 2007

AbstractPurposeTo understand the diffusion attenuated MR signal from normal and ischemic brain tissue in order to extract structural and physiological information using mathematical modeling, taking into account the transverse relaxation rates in gray matter.Materials and MethodsWe fit our diffusion model to the diffusion‐weighted MR signal obtained from cortical gray matter in healthy subjects. Our model includes variable volume fractions, intracellular restriction effects, and exchange between compartments in addition to individual diffusion coefficients and transverse relaxation rates for each compartment. A global optimum was found from a wide range of parameter permutations using cluster computing. We also present simulations of cell swelling and changes of exchange rate and intracellular diffusion as possible cellular mechanisms in ischemia.ResultsOur model estimates an extracellular volume fraction of 0.19 in accordance with the accepted value from histology. The absolute apparent diffusion coefficient obtained from the model was similar to that of experiments. The model and the experimental results indicate significant differences in diffusion and transverse relaxation between the tissue compartments and slow water exchange. Our model reproduces the signal changes observed in ischemia via physiologically credible mechanisms.ConclusionOur modeling suggests that transverse relaxation has a profound influence on the diffusion attenuated MR signal. Our simulations indicate cell swelling as the primary cause of the diffusion changes seen in the acute phase of brain ischemia. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Evaluation of ganglion cysts using vastly undersampled isotropic projection reconstruction (VIPR)
Authors: Amrami Kimberly K. , Desy Nicholas M. , Stanley David W. , Skinner John A. , Felmlee Joel P. , Barger Andrew V. , Block Walter F. , Spinner Robert J. 
Published: August 2007

AbstractFor some atypical para‐articular ganglia, the presence of a joint connection is highly controversial. The proper preoperative diagnosis and identification of this joint connection for ganglion cysts is important for patient treatment and outcome. MRI is the imaging modality of choice when evaluating such lesions, but the detection of subtle joint connections remains difficult with conventional MR protocols. We investigated the utility of a steady‐state free‐precession acquisition with isotropic high resolution using the vastly undersampled isotropic projection reconstruction (VIPR) pulse sequence to determine if joint connections for ganglion cysts could be seen more effectively, using the knee region as a model. We evaluated four patients: two with peroneal intraneural ganglion cysts, one with adventitial cystic disease of the popliteal artery, and one patient with a more typical extraneural (intramuscular) cyst. Both conventional MR and VIPR techniques were used. In our clinical experience, we found VIPR to be superior to conventional MR techniques in detecting and depicting joint connections in typical and atypical ganglion cysts around the knee. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Quantitative regional oxygen transfer imaging of the human lung
Authors: Arnold Johannes F.T. , Kotas Markus , Fidler Florian , Pracht Eberhard D. , Flentje Michael , Jakob Peter M. 
Published: August 2007

AbstractPurposeTo demonstrate that the use of nonquantitative methods in oxygen‐enhanced (OE) lung imaging can be problematic and to present a new approach for quantitative OE lung imaging, which fulfills the requirements for easy application in clinical practice.Materials and MethodsA total of 10 healthy volunteers and three non‐small‐cell lung cancer (NSCLC) patients were examined using a 1.5T scanner. OE imaging was performed using a snapshot fast low‐angle shot (FLASH) T1‐mapping technique (TE = 1.4 msec, TR = 3.5 msec) as well as a series of T1‐weighted inversion recovery (IR) half‐ Fourier acquisition single‐shot turbo spin‐echo (HASTE) (TEeffective = 43 msec, TEinter = 4.2 msec, and inversion time [TI] = 1200 msec) images. Semiquantitative relative signal enhancement ratios (RER) of T1‐weighted images before and after inhalation of oxygen‐enriched gas were compared to the quantitative change in T1. A hybrid method is proposed that combines the advantages of T1‐weighted imaging with the quantification provided by T1‐mapping. To this end, the IR‐HASTE images were transformed into quantitative parameter maps. To prevent mismatching and incorrect parameter maps, retrospective image selection was performed using a postprocessing navigator technique.ResultsThe RER was dependent on the intrinsic values of T1 in the lung. Quantitative parameters, such as the decrease of T1 after switching the breathing gas, were more suited to oxygen transfer quantification than to relative signal enhancement. The mean T1 value during inhalation of room air (T1,room) for the volunteers was 1260 msec. This value decreased by about 10% after switching the breathing gas to carbogen. For the patients, the mean T1,room value was 1182 msec, which decreased by about 7% when breathing carbogen. The parameter maps generated using the proposed hybrid method deviated, on average, only about 1% from the T1‐maps.ConclusionFor the purpose of intersubject comparison, OE lung imaging should be performed quantitatively. The proposed hybrid technique produced reliable quantitative results in a short amount of time and, therefore, is suited for clinical use. J. Magn Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Comparison of three accelerated pulse sequences for semiquantitative myocardial perfusion imaging using sensitivity encoding incorporating temporal filtering (TSENSE)
Authors: Weber Stefan , Kronfeld Andrea , Kunz R. Peter , Fiebich Martin , Horstick Georg , Kreitner Karl‐Friedrich , Schreiber Wolfgang G. 
Published: August 2007

AbstractPurposeTo investigate the parallel acquisition technique sensitivity encoding incorporating temporal filtering (TSENSE) with three saturation‐recovery (SR) prepared pulse sequences (SR turbo fast low‐angle shot [SR‐TurboFLASH], SR true fast imaging with steady precession [SR‐TrueFISP], and SR‐prepared segmented echo‐planar‐imaging [SR‐segEPI]) for semiquantitative first‐pass myocardial perfusion imaging.Materials and MethodsIn blood‐ and tissue‐equivalent phantoms the relationship between signal intensity (SI) and contrast‐medium concentration was evaluated for the three pulse sequences. In volunteers, signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), and normalized upslopes (NUS) were calculated from signal–time curves (STC). Moreover, artifacts, image noise, and overall image quality were qualitatively evaluated.ResultsPhantom data showed a 40% increased linear range of the relation between SI and contrast‐medium concentration with TSENSE. In volunteers, TSENSE introduced significantly residual artifacts and loss in SNR and CNR. No differences were found for NUS values with TSENSE. SR‐TrueFISP yielded highest SNR, CNR, and quality scores. However, in SR‐True‐FISP images, dark‐banding artifacts were most pronounced. NUS values obtained with SR‐TrueFISP were significantly higher and with SR‐segEPI significantly lower than with SR‐TurboFLASH.ConclusionSemiquantitative myocardial perfusion imaging can significantly benefit from TSENSE due to shorter acquisition times and increased linearity of the pulse sequences. Among the three pulse sequences tested, SR‐TrueFISP yielded best image quality. SR‐segEPI proved to be an interesting alternative due to shorter acquisition times, higher linearity and fewer dark‐banding artifacts. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Improvement of the diffusion‐weighted images acquired with radial trajectories using projection data regeneration
Authors: Han Yeji , Hwang JinYoung , Chung Jun‐Young , Yun Sungdae , Park HyunWook 
Published: August 2007

AbstractPurposeTo reduce the artifacts due to pulsatile motion artifacts in diffusion‐weighted imaging (DWI) with radial trajectories and to improve the image quality using projection data regeneration.Materials and MethodsThe projection data is obtained by a radial spin‐echo DWI (rSE‐DWI) sequence, from which a temporary image is generated using the inverse Radon transform (IRT). The projection data include some degraded data due to cardiac pulsatile motion. The degraded data are then replaced with data that are regenerated using the Radon transform (RT) of the temporary image. The proposed method for image quality improvement is demonstrated through a computer simulation and in vivo images obtained by rSE‐DWI.ResultsIn general, electrocardiograph (ECG) triggering is used to reduce the degradation of projection data in the DWI with radial trajectories, where the amount of degradation depends on the cardiac phase. Cardiac gating reduces the artifacts resulting from the cardiac pulsatile motion to a certain extent only. The proposed projection data regeneration method successfully improves image quality.ConclusionThe regeneration method based on back‐projection reconstruction effectively uses the features of the degraded projections having lower signal intensity than the normal projections, resulting in image quality improvement without acquisition of additional data. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Effect of deficit irrigation on apricot fruit quality at harvest and during storage
Authors: Pérez‐Pastor Alejandro , Ruiz‐Sánchez Maria Carmen , Martínez Juan A , Nortes Pedro A , Artés Francisco , Domingo Rafael 
Published: August 2007

AbstractThe effect of different irrigation strategies on the fruit quality at harvest and during storage at 1 °C of 'Búlida' apricots (Prunus armeniaca L.) was studied. Irrigation treatments consisted of a control irrigated at 100% of crop evapotranspiration (ETc) throughout the season, and two deficit irrigation treatments consisting of continuous irrigation at 50% of control, and regulated deficit irrigation (RDI) at 100% of ETc during the critical periods (second rapid fruit growth and early post‐harvest) and at 25% during the rest of the season. Fruits at harvest from both deficit irrigation treatments showed higher values of total soluble solids (TSS), titratable acidity and hue angle (h°) than control fruits, whereas their diameter, fresh weight, firmness and maturity index values were similar to those in the control. During the first 10 days of the 30‐day chilling storage period, higher TSS and h° values were found in deficit irrigated fruits, whilst the other parameters were similar for all treatments. Weight loss and fungal attacks (mainly Rhizopus sp. and Monilinia sp.) during a subsequent retail sale period of 4 days at 13 °C were the lowest in RDI. Deficit irrigation was demonstrated to be commercially advantageous for keeping fruit quality, saving considerable amounts of water. Copyright © 2007 Society of Chemical Industry
Reconstruction with pasteurized autograft‐total hip prosthesis composite for periacetabular tumors
Authors: Jeon Dae‐Geun , Kim Min Suk , Cho Wan Hyeong , Song Won Seok , Lee Soo‐Yong 
Published: August 2007

AbstractBackgroundWith the development of preoperative adjuvant treatment, imaging techniques, and improvement of surgical technique, limb salvage is now possible even in patients with pelvic tumors. However, reconstruction after periacetabular resection is complicated and challenging.MethodsWe retrospectively evaluated the usefulness of pasteurized autograft‐total hip composite in pelvic reconstruction with regard to graft survival, union, graft‐related complications, and functional outcome in 14 patients with periacetabular tumor.ResultsThe 5‐year and 10‐year survival rates of the pasteurized bones were 64.3% and 32.1%, respectively. Major complications that necessitated graft removal included infection in three, fracture in two, and loosening in three patients. The average functional score of seven long‐term successful patients was 25.6 (85.2%).ConclusionsIn spite of the high complication rate, pasteurized autograft can be considered as an option for periacetabular reconstruction in the selected patients who meet the following criteria. First, iliopectineal and ilioischial lines are radiologically intact; second, the tumor volume is small (preferably less than 100 ml). J. Surg. Oncol. 2007;96:493–502. © 2007 Wiley‐Liss, Inc.
Structure–retention relationship study of diastereomeric (Z)‐ and (E)‐2‐alkylidene‐4‐oxothiazolidines
Authors: Natić Maja , Marković Rade , Milojković‐Opsenica Dušanka , Tešić Živoslav 
Published: August 2007

AbstractQuantitative structure–retention relationship (QSRR) was developed for a series of the (Z)‐ and (E)‐2‐alkylidene‐4‐oxothiazolidine derivatives by the multiple linear regression (MLR) analysis. Full geometry optimization based on Austin Model 1 (AM1) semiempirical molecular orbital method was carried out and a set of physicochemical molecular descriptors was calculated from the optimized structures. In order to obtain useful experimental parameters, the lipophilic character of analytes was measured by RP‐TLC, and lipophilicity parameters were correlated with physicochemical structural descriptors. Statistically significant and physically meaningful structure–retention relationships were obtained.
CAESURA Studies of Helical Jump Motions in Semi‐Crystalline Polymers
Authors: Shao Limin , Titman Jeremy J. 
Published: August 2007

AbstractApplications of the CAESURA experiment to studies of helical jump motions in semi‐crystalline polymers are described. CAESURA is a recently proposed magic angle spinning exchange NMR experiment which provides detailed information about the timescale and geometry of molecular motions. The potential utility of CAESURA in studies of helical jump motions in a range semi‐crystalline polymers is illustrated using simulated data. In addition, a full experimental investigation of isotactic poly(propylene) is described which confirms the geometry of the helical jump motion and provides a measurement of the jump rate.magnified image
On the number of positive solutions of elliptic systems
Authors: O'Regan Donal , Wang Haiyan 
Published: August 2007

AbstractThe paper deals with the existence, multiplicity and nonexistence of positive radial solutions for the elliptic system div(|∇|p –2∇) + λki (|x |) fi (u1, …,un) = 0, p > 1, R1 < |x | < R2, ui (x) = 0, on |x | = R1 and R2, i = 1, …, n, x ∈ ℝN , where ki and fi, i = 1, …, n, are continuous and nonnegative functions. Let u = (u1, …, un), φ (t) = |t |p –2t, fi0 = lim‖u‖→0((fi (u))/(φ (‖u‖))), fi∞= lim‖u‖→∞((fi (u))/(φ (‖u‖))), i = 1, …, n, f = (f1, …, fn), f0 = ∑n i =1 fi 0 and f∞ = ∑n i =1 fi ∞. We prove that either f0 = 0 and f∞ = ∞ (superlinear), or f0 = ∞and f∞ = 0 (sublinear), guarantee existence for all λ > 0. In addition, if fi (u) > 0 for ‖u‖ > 0, i = 1, …, n, then either f0 = f∞ = 0, or f0 = f∞ = ∞, guarantee multiplicity for sufficiently large, or small λ, respectively. On the other hand, either f0 and f∞ > 0, or f0 and f∞ < ∞ imply nonexistence for sufficiently large, or small λ, respectively. Furthermore, all the results are valid for Dirichlet/Neumann boundary conditions. We shall use fixed point theorems in a cone. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Clarkson's inequality in the real case
Authors: Maligranda Lech , Sabourova Natalia 
Published: August 2007

AbstractThe best constant in a generalized complex Clarkson inequality is Cp,q (ℂ) = max {21–1/p , 21/q , 21/q –1/p +1/2} which differs moderately from the best constant in the real case Cp,q (ℝ) = max {21–1/p , 21/q ,Bp,q }, where . For 1 < q < 2 < p < ∞ the constant Cp,q (ℝ) is equal to Bp,q and these numbers are difficult to calculate in general. As applications of the generalized Clarkson inequalities the (p, q)‐Clarkson inequalities in Lebesgue spaces, in mixed norm spaces and in normed spaces are presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)