bluuebunny/crossref_metadata_2025 huggingface dataset:
A simulation experiment for optimal design hyetograph selection
Authors: Alfieri Lorenzo , Laio Francesco , Claps Pierluigi
Published: September 2007

The aim of this work is to assess the accuracy of literature design hyetographs for the evaluation of peak discharges during flood events. Five design hyetographs are examined in a set of simulations, based upon the following steps: (i) an ideal river basin is defined, characterized by a Beta distribution shaped unit hydrograph (UH); (ii) 1000 years of synthetic rainfall are artificially generated; (iii) a discharge time‐series is obtained from the convolution of the rainfall time‐series and the UH, and the reference T‐years flood is computed from this series; (iv) for the same return period T, the parameters of the intensity–duration–frequency (IDF) curve are estimated from the 1000 years of synthetic rainfall; (v) five design hyetographs are determined from the IDF curves and are convolved with the discrete UH to find the corresponding design hydrographs; (vi) the hydrograph peaks are compared with the reference T‐years flood and the advantages and drawbacks of each of the five approaches are evaluated. The rainfall and UH parameters are varied, and the whole procedure is repeated to assess the sensitivity of results to the system configuration.

We found that all design hyetographs produce flood peak estimates that are consistently biased in most of the climatic and hydrologic conditions considered. In particular, significant underestimation of the design flood results from the adoption of any rectangular hyetograph used in the context of the rational formula. In contrast, the Chicago hyetograph tends to overestimate peak flows. In two cases it is sufficient to multiply the result by a constant scaling factor to obtain robust and nearly unbiased estimates of the design floods. Copyright © 2007 John Wiley & Sons, Ltd.
Diurnal variability in riverine dissolved organic matter composition determined by in situ optical measurement in the San Joaquin River (California, USA)
Authors: Spencer Robert G. M. , Pellerin Brian A. , Bergamaschi Brian A. , Downing Bryan D. , Kraus Tamara E. C. , Smart David R. , Dahlgren Randy A. , Hernes Peter J.
Published: September 2007

Dissolved organic matter (DOM) concentration and composition in riverine and stream systems are known to vary with hydrological and productivity cycles over the annual and interannual time scales. Rivers are commonly perceived as homogeneous with respect to DOM concentration and composition, particularly under steady flow conditions over short time periods. However, few studies have evaluated the impact of short term variability (<1 day) on DOM dynamics. This study examined whether diurnal processes measurably altered DOM concentration and composition in the hypereutrophic San Joaquin River (California) during a relatively quiescent period. We evaluated the efficacy of using optical in situ measurements to reveal changes in DOM which may not be evident from bulk dissolved organic carbon (DOC) measurement alone. The in situ optical measurements described in this study clearly showed for the first time diurnal variations in DOM measurements, which have previously been related to both composition and concentration, even though diurnal changes were not well reflected in bulk DOC concentrations. An apparent asynchronous trend of DOM absorbance and chlorophyll‐a in comparison to chromophoric dissolved organic matter (CDOM) fluorescence and spectral slope S290–350 suggests that no one specific CDOM spectrophotometric measurement explains absolutely DOM diurnal variation in this system; the measurement of multiple optical parameters is therefore recommended. The observed diurnal changes in DOM composition, measured by in situ optical instrumentation likely reflect both photochemical and biologically‐mediated processes. The results of this study highlight that short‐term variability in DOM composition may complicate trends for studies aiming to distinguish different DOM sources in riverine systems and emphasizes the importance of sampling specific study sites to be compared at the same time of day. The utilization of in situ optical technology allows short‐term variability in DOM dynamics to be monitored and serves to increase our understanding of its processing and fundamental role in the aquatic environment. Copyright © 2007 John Wiley & Sons, Ltd.
Macrophages function as a ferritin iron source for cultured human erythroid precursors
Authors: Leimberg Moshe J. , Prus Eugenia , Konijn Abraham M. , Fibach Eitan
Published: September 2007

Iron is essential for the survival as well as the proliferation and maturation of developing erythroid precursors (EP) into hemoglobin‐containing red blood cells. The transferrin–transferrin receptor pathway is the main route for erythroid iron uptake. Using a two‐phase culture system, we have previously shown that placental ferritin as well as macrophages derived from peripheral blood monocytes could partially replace transferrin and support EP growth in a transferrin‐free medium. We now demonstrate that in the absence of transferrin, ferritin synthesized and secreted by macrophages can serve as an iron source for EP. Macrophages trigger an increase in both the cytosolic and the mitochondrial labile iron pools, in heme and in hemoglobin synthesis, along with a decrease in surface transferrin receptors. Inhibiting macrophage exocytosis, binding extracellular ferritin with specific antibodies, inhibiting EP receptor‐mediated endocytosis or acidification of EP lysosomes, all resulted in a decreased EP growth when co‐cultured with macrophages under transferrin‐free conditions. The results suggest that iron taken up by macrophages is incorporated mainly into their ferritin, which is subsequently secreted by exocytosis. Nearby EP are able to take up this ferritin probably through clathrin‐dependent, receptor‐mediated endocytosis into endosomes, which following acidification and proteolysis release the iron from the ferritin, making it available for regulatory and synthetic purposes. Thus, macrophages support EP development under transferrin‐free conditions by delivering essential iron in the form of metabolizable ferritin. J. Cell. Biochem. 103: 1211–1218, 2008. © 2007 Wiley‐Liss, Inc.
Retinoids in biological control and cancer
Authors: Fields Anthonise Louis , Soprano Dianne Robert , Soprano Kenneth J.
Published: September 2007

More than 80 years ago, Wolbach and Howe provided the first evidence suggesting a link between alterations within human cells that lead to malignancies and vitamin A deficiencies (Wolbach and Howe 1925 Nutr. Rev. 36: 16–19). Since that time, epidemiological, preclinical and clinical studies have established a causative relationship between vitamin A deficiency and cancer. Laboratory research has provided insight into the intracellular targets, various signaling cascades and physiological effects of the biologically‐active natural and synthetic derivatives of vitamin A, known as retinoids. Collectively, this body of research supports the concept of retinoids as chemopreventive and chemotherapeutic agents that can prevent epithelial cell tumorigenesis by directing the cells to either differentiate, growth arrest, or undergo apoptosis, thus preventing or reversing neoplasia. Continued refinement of the retinoid signaling pathway is essential to establishing their use as effective therapeutics for tumor subtypes whose oncogenic intracellular signaling pathways can be blocked or reversed by treatment with retinoids. J. Cell. Biochem. 102: 886–898, 2007. © 2007 Wiley‐Liss, Inc.
Ultraviolet radiation (UVR) activates p38 MAP kinase and induces post‐transcriptional stabilization of the C/EBPδ mRNA in G0 growth arrested mammary epithelial cells
Authors: Li Bin , Si Junling , DeWille James W.
Published: September 2007

The G0 growth arrest (quiescent) state is highly conserved in evolution to promote survival under adverse environmental conditions. To maintain viability, G0 growth arrested cells limit gene expression to essential growth control and pro‐survival genes. CCAAT enhancer binding proteinδ (C/EBPδ), a member of the C/EBP family of nuclear proteins, is highly expressed in G0 growth arrested mammary epithelial cells (MECs). Although C/EBPδ gene transcription is elevated during G0 growth arrest, C/EBPδ mRNA and protein are relatively short lived, suggesting tight control of the cellular C/EBPδ content in unstressed, quiescent cells. Treatment of G0 growth arrested MECs with ultraviolet radiation (UVR) dramatically increases the C/EBPδ mRNA half‐life (∼4‐fold) and protein content (∼3‐fold). The mRNA stabilizing effects of UVR treatment are mediated by the C/EBPδ mRNA 3′untranslated region, which contains an AU rich element. UVR increased p38 MAP kinase (MAPK) activation and SB203580, a p38 MAPK inhibitor, blocked UVR‐induced C/EBPδ mRNA stabilization. UVR increased the nuclear to cytoplasmic translocation of HuR, an ARE‐binding protein that functions in mRNA stabilization. Finally, HuR siRNA treatment blocked UVR‐induced stabilization of the C/EBPδ and C/EBPβ mRNAs but had no effect on C/EBPζ (CHOP) mRNA stability. In summary, G0 growth arrested MECs respond to UVR treatment by activating p38 MAPK, increasing HuR translocation and HuR/C/EBPδ mRNA binding and stabilizing the C/EBPδ mRNA. These results identify post‐transcriptional stabilization of the C/EBPδ mRNA as a mechanism to increase C/EBPδ levels in the stress response of quiescent cells to UVR. J. Cell. Biochem. 103: 1657–1669, 2008. © 2007 Wiley‐Liss, Inc.
Colle‐Salvetti‐type correction for electron–nucleus correlation in the nuclear orbital plus molecular orbital theory
Authors: Imamura Yutaka , Kiryu Hiroyoshi , Nakai Hiromi
Published: September 2007

A Colle‐Salvetti (CS)‐type electron–nucleus correction in the nuclear orbital plus molecular orbital theory is proposed. The CS‐type correction is designed to satisfy the cusp condition for the electron–nucleus interaction. Since the CS‐type correction is expressed in terms of the electron and nucleus densities, its evaluation is computationally feasible. Numerical assessment confirms that the CS‐type correction performs well for the small G2 set. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
OPN deficiency suppresses appearance of odontoclastic cells and resorption of the tooth root induced by experimental force application
Authors: Chung Chooryung J. , Soma Kunimichi , Rittling Susan R. , Denhardt David T. , Hayata Tadayoshi , Nakashima Kazuhisa , Ezura Yoichi , Noda Masaki
Published: September 2007

Osteopontin (OPN) is a major non‐collagenous bone matrix protein implicated in the regulation of cell function. Although OPN is rich in the cementum of the tooth, the significance of OPN in this tissue is not understood. Tooth root resorption is the most frequent complication of orthodontic tooth movement (TM). The objective of this study was to examine the pathophysiological role of OPN in cementum of the tooth root. For this purpose, the upper right first molar (M1) in OPN‐deficient and wild‐type (WT) mice was subjected to mechanical force via 10 gf NiTi coil spring while the left side molar was kept intact to serve as an internal control. Micro‐CT section and the level of tartrate resistant acid phosphatase (TRAP)‐positive cells on the tooth root surface defined as odontoclasts were quantified at the end of the force application. In WT mice, force application to the tooth caused appearance of odontoclasts around the mesial surface of the tooth root resulting in tooth root resorption. In contrast, OPN deficiency significantly suppressed the force‐induced increase in the number of odontoclasts and suppressed root resorption. This force application also induced increase in the number of TRAP‐positive cells in the alveolar bone on the pressure side defined as osteoclasts, while the levels of the increase in osteoclastic cell number in such alveolar bone were similar between the OPN‐deficient and WT mice. These observations indicate that OPN deficiency suppresses specifically tooth root resorption in case of experimental force application. J. Cell. Physiol. 214: 614–620, 2008. © 2007 Wiley‐Liss, Inc.
Protease‐mediated arsenic prodrug strategy in cancer and infectious diseases: A hypothesis for targeted activation
Authors: Bellacchio Emanuele , Paggi Marco G.
Published: September 2007

A strategy for the selective in vivo activation of prodrugs by proteases is presented. The approach is based on the design of polythiol peptides able to neutralize the toxicity of As(III) through chelation, and contemporarily to be recognized as substrates of a disease‐linked specific protease. Enzyme digestion implies conversion of such polythiol peptides into monothiol fragments with irreversible loss of the ability to chelate the metalloid, thus triggering the release in its free and pharmacologically effective form. The proteases whose activity appears dramatically up‐regulated in various pathologies, ranging from cancer to infectious diseases, can be conveniently employed as prodrug activators in the disease microenvironment. The design of the representative peptide shown here has been assisted by molecular modeling in order to fulfill the dual characteristic to be an efficient As(III) chelator and simultaneously a substrate of the matrix metalloproteinase‐9 (MMP‐9) whose activity results dramatically increased at the surface of cells affected by several pathologies. J. Cell. Physiol. 214: 681–686, 2008. © 2007 Wiley‐Liss, Inc.
High extracellular inorganic phosphate concentration inhibits RANK–RANKL signaling in osteoclast‐like cells
Authors: Mozar Anaïs , Haren Nathalie , Chasseraud Maud , Louvet Loïc , Mazière Cécile , Wattel Alice , Mentaverri Romuald , Morlière Patrice , Kamel Saïd , Brazier Michel , Mazière Jean C. , Massy Ziad A.
Published: September 2007

In this work, we investigated the effect of inorganic phosphate (Pi) on the differentiation of monocyte/macrophage precursors into an “osteoclastic” phenotype, and we delineated the molecular mechanisms which could be involved in this phenomenon. This was achieved by stimulating human peripheral blood monocytic cells and RAW 264.7 monocyte–macrophage precursor cells to differentiate into osteoclast‐like cells in the presence of receptor activator of NF‐κB ligand (RANKL) and macrophage colony‐stimulating factor (M‐CSF). RANKL has been previously reported to stimulate the signaling kinases ERK 1/2, p38, Akt, JNK, and the DNA‐binding activity of the transcription factors AP‐1 and NF‐κB. Increase in extracellular Pi concentration (1.5–4.5 mM) dose‐dependently inhibits both osteoclastic differentiation and bone resorption activity induced by RANKL and M‐CSF. Pi was found to specifically inhibit the RANKL‐induced JNK and Akt activation, while RANKL‐induced p38 and ERK 1/2 phosphorylation were not significantly affected. Moreover, we found that Pi significantly reduced the RANKL‐stimulated DNA‐binding activity of NF‐κB. The effects of Pi on osteoclast differentiation and DNA‐binding activity of NF‐κB were prevented by Foscarnet®, a sodium–phosphate cotransport inhibitor, suggesting that the effects of Pi occur subsequently to its intake. These results demonstrate that Pi downregulates the differentiation of osteoclasts via a negative feedback exerted on RANK–RANKL signaling. J. Cell. Physiol. 215: 47–54, 2008. © 2007 Wiley‐Liss, Inc.
Growth and patterning are evolutionarily dissociated in the vestigial wing discs of workers of the red imported fire ant, Solenopsis Invicta
Authors: Bowsher Julia H. , Wray Gregory A. , Abouheif Ehab
Published: September 2007

Over the last decade, it has become clear that organismal form is largely determined by developmental and evolutionary changes in the growth and pattern formation of tissues. Yet, there is little known about how these two integrated processes respond to environmental cues or how they evolve relative to one another. Here, we present the discovery of vestigial wing imaginal discs in worker larvae of the red imported fire ant, Solenopsis invicta. These vestigial wing discs are present in all worker larvae, which is uncommon for a species with a large worker size distribution. Furthermore, the growth trajectory of these vestigial discs is distinct from all of the ant species examined to date because they grow at a rate slower than the leg discs. We predicted that the growth trajectory of the vestigial wing discs would be mirrored by evolutionary changes in their patterning. We tested this prediction by examining the expression of three patterning genes, extradenticle, ultrabithorax, and engrailed, known to underlie the wing polyphenism in ants. Surprisingly, the expression patterns of these three genes in the vestigial wing discs was the same as those found in ant species with different worker size distributions and wing disc growth than fire ants. We conclude that growth and patterning are evolutionarily dissociated in the vestigial wing discs of S. invicta because patterning in these discs is conserved, whereas their growth trajectories are not. The evolutionary dissociation of growth and patterning may be an important feature of gene networks that underlie polyphenic traits. J. Exp. Zool. (Mol. Dev. Evol.) 308B:769–776, 2007. © 2007 Wiley‐Liss, Inc.
Building on a 50‐year legacy of the MRC Cyclotron Unit: the Hammersmith radiochemistry pioneering journey
Authors: Brady Frank , Clark John C. , Luthra Sajinder K.
Published: September 2007

The Medical Research Council Cyclotron Unit (MRC CU) situated at Hammersmith Hospital, London, is widely recognised for its pioneering developments in radiochemistry. The MRC CU became one of the largest and most comprehensive PET centres in the world. More recently, under the umbrella of a public/private partnership between the MRC and Amersham Health (now part of GE Healthcare) this centre has continued to advance PET research.

This article reviews the 50‐year history of radiochemistry development and application for medical research at Hammersmith. Copyright © 2007 John Wiley & Sons, Ltd.
Fifty years of radiopharmacy at Rossendorf
Authors: Spies Hartmut , Steinbach Jörg
Published: September 2007

The Central Institute of Nuclear Research was founded in Rossendorf near Dresden in 1956 and the production of radioactive materials and radiopharmaceuticals was started in 1958. The basis for the production was the irradiation of targets in the Rossendorf research reactor and, to a lower extent, at the Rossendorf cyclotron U‐120.

This paper gives an account of the accomplishments of Rossendorf in the field of radiopharmacy from the early fifties, in the former department of ‘Radioactive Isotopes’, till to date. The production of radiopharmaceuticals is reviewed in brief. Investigations in technetium chemistry and pharmacology are discussed in more detail, and efforts to set up positron emission tomography (PET) in Rossendorf, as the first PET centre in the former Eastern Block, are described. Nowadays, the research in radiopharmacy is carried out within the well‐equipped Institute of Radiopharmacy, established in 1992. Copyright © 2007 John Wiley & Sons, Ltd.
Energy landscape roughness of the streptavidin–biotin interaction
Authors: Rico Félix , Moy Vincent T.
Published: September 2007

Molecular interactions between receptors and ligands can be characterized by their free energy landscape. In its simplest representation, the energy landscape is described by a barrier of certain height and width that determines the dissociation rate of the complex, as well as its dynamic strength. Some interactions, however, require a more complex landscape with additional barriers and roughness along the reaction coordinate. This roughness slows down the dissociation kinetics of the interaction and contributes to its dynamic strength. The streptavidin–biotin complex has been extensively studied due to its remarkably low dissociation kinetics. However, single molecule measurements from independent experiments showed scattered and disparate results. In this work, the energy landscape roughness of the streptavidin–biotin interaction was estimated to be in the range of 5–8kBT using dynamic force spectroscopy (DFS) measurements at three different temperatures. These results can be used to explain both its slow dissociation kinetics and the discrepancies in the reported force measurements. Copyright © 2007 John Wiley & Sons, Ltd.
Manganese‐enhanced MRI in a rat model of Parkinson's disease
Authors: Pelled Galit , Bergman Hagai , Ben‐Hur Tamir , Goelman Gadi
Published: September 2007

Purpose

To measure intra‐ and inter‐hemispheric connectivity within the basal ganglia (BG) nuclei in healthy and in unilateral 6‐hydroxydopamine (6‐OHDA) Parkinson disease rat model in order to test the BG interhemispheric connectivity hypothesis.

Material and Methods

The manganese‐enhanced MRI (MEMRI) method with direct injection of manganese chloride into the entopeduncular (EP), substantia nigra (SN), and the Habenula nuclei in unilateral 6‐OHDA (N = 22) and sham‐operated (N = 16) rat groups was used. MEMRI measurements were applied before, 3, 24, and 48 hours post‐manganese injection. Signal enhancements in T1‐weighted images were compared between groups.

Results

Manganese injection into the EP nucleus resulted with bihemispheric signal enhancements in the habenular complex (Hab) at both groups with stronger enhancements in the 6‐OHDA group. It also exhibited lower sensorimotor cortex signal enhancement in the 6‐OHDA rat group. SN manganese injection caused enhanced anteroventral thalamic and habenular nuclei signals in the 6‐OHDA rat group. Manganese habenula injection revealed enhanced interpeduncular (IP) and raphe nuclei signals of the 6‐OHDA rat group.

Conclusion

Modulations in the effective intra‐ and interhemispheric BG connectivity in unilateral 6‐OHDA Parkinson's disease (PD) rat model support the BG interhemispheric connectivity hypothesis and suggest a linkage between the dopaminergic and serotonergic systems in PD, in line with clinical symptoms. J. Magn. Reson. Imaging 2007;26:863–870. © 2007 Wiley‐Liss, Inc.
Coronary MR angiography at 3T during diastole and systole
Authors: Gharib Ahmed M. , Herzka Daniel A. , Ustun Ali O. , Desai Milind Y. , Locklin Julia , Pettigrew Roderic I. , Stuber Matthias
Published: September 2007

Purpose

To investigate the impact of end‐systolic imaging on quality of right coronary magnetic resonance angiography (MRA) in comparison to diastolic and to study the effect of RR interval variability on image quality.

Materials and Methods

The right coronary artery (RCA) of 10 normal volunteers was imaged at 3T using parallel imaging (sensitivity encoding [SENSE]). Navigator‐gated three‐dimensional (3D) gradient echo was used three times: 1) end‐systolic short acquisition (SS): 35‐msec window; 2) diastolic short (DS): middiastolic acquisition using 35‐msec window; and 3) diastolic long (DL): 75‐msec diastolic acquisition window. Vectorcardiogram (VCG) data was used to analyze RR variability. Vessel sharpness, length, and diameter were compared to each other and correlated with RR variability. Blinded qualitative image scores of the images were compared.

Results

Quantitative and qualitative parameters were not significantly different and showed no significant correlation with RR variability.

Conclusion

Imaging the RCA at 3T during the end‐systolic rest period using SENSE is possible without significant detrimental effect on image quality. Breaking away from the standard of imaging only during diastole can potentially improve image quality in tachycardic patients or used for simultaneous imaging during both periods in a single scan. J. Magn. Reson. Imaging 2007;26:921–926. © 2007 Wiley‐Liss, Inc.
First‐time shoulder dislocation: High prevalence of labral injury and age‐related differences revealed by MR arthrography
Authors: Antonio Gregory E. , Griffith James F. , Yu Alfred B. , Yung Patrick S.H. , Chan Kai Ming , Ahuja Anil T.
Published: September 2007

Purpose

To evaluate abnormalities and age‐related differences after first‐time shoulder dislocation.

Materials and Methods

MRA images of first‐time dislocators were assessed for labral‐ligamentous‐capsular / rotator cuff abnormalities and analyzed the age‐related differences (< and ≥30 years old).

Results

Sixty‐six patients (34 <30 years old vs. 32 ≥30 years; 51 males; all anterior dislocations) were imaged. Forty‐eight patients (73%) showed anteroinferior labral avulsion, consisting of: 6% (4/34 vs. 0/32) Perthes; 23% (8/34 vs. 7/32) free ALPSA (anterior labrum periosteal sleeve avulsion) lesion); 6% (1/34 vs. 3/32) adherent ALPSA; 23% (9/34 vs. 6/32) Bankart; 14% (5/34 vs. 4/32) inferiorly displaced avulsed labrum; 2% (1/34 vs. 0/32) GLAD. Extensive labral detachment (extended above 3 o'clock position) was present in 31% (11/28 vs. 4/20). There were 14% (6/34 vs. 3/32) superior labrum anterior‐posterior (SLAP) lesion; 27% (1/34 vs. 17/34) rotator cuff tendon tear; 71% (25/34 vs. 22/32) Hill‐Sachs defect. Young patients were more likely to have extensive labral avulsions (P = 0.054), but less likely to have rotator cuff tears (P < 0.001).

Conclusion

A high prevalence and wide variety of labral avulsions after first‐time shoulder dislocation, especially adherent ALPSA, inferiorly displaced avulsed labrum, or GLAD lesion, may influence treatment choice and outcome, suggesting a role for early MRA to assist in treatment triage. J. Magn. Reson. Imaging 2007;26:983–991. © 2007 Wiley‐Liss, Inc.
Reconstruction of the human visual system based on DTI fiber tracking
Authors: Staempfli Philipp , Rienmueller Anna , Reischauer Carolin , Valavanis Anton , Boesiger Peter , Kollias Spyridon
Published: September 2007

Purpose

To apply and to evaluate the newly developed advanced fast marching algorithm (aFM) in vivo by reconstructing the human visual pathway, which is characterized by areas of extensive fiber crossing and branching, i.e., the optic chiasm and the lateral geniculate nucleus (LGN).

Materials and Methods

Diffusion tensor images were acquired in 10 healthy volunteers. Due to the proximity to bony structures and air‐filled spaces of the optic chiasm, a high sensitivity encoding (SENSE) reduction factor was applied to reduce image distortions in this area. To reconstruct the visual system, three different seed areas were chosen separately. The results obtained by the aFM tracking algorithm were compared and validated with known anatomy.

Results

The visual system could be reconstructed reproducibly in all subjects and the reconstructed fiber pathways are in good agreement with known anatomy.

Conclusion

The present work shows that the advanced aFM, which is especially designed for overcoming tracking limitations within areas of extensive fiber crossing, handles the fiber crossing and branching within the optic chiasm and the LGN correctly, thus allowing the reconstruction of the entire human visual fiber pathway, from the intraorbital segment of the optic nerves to the visual cortex. J. Magn. Reson. Imaging 2007;26:886–893. © 2007 Wiley‐Liss, Inc.
Hepatic viscoelastic parameters measured with MR elastography: Correlations with quantitative analysis of liver fibrosis in the rat
Authors: Salameh Najat , Peeters Frank , Sinkus Ralph , Abarca‐Quinones Jorge , Annet Laurence , ter Beek Leon C. , Leclercq Isabelle , Van Beers Bernard E.
Published: September 2007

Purpose

To determine the correlations between the viscoelastic parameters of the liver measured with in vivo MR elastography and quantitative analysis of liver fibrosis.

Materials and Methods

MR elastography of the liver was performed in 10 rats with hepatic fibrosis induced by intraperitoneal carbon tetrachloride (CCl4) injections and five normal rats. Longitudinal waves of 200 MHz were transmitted into the liver with a mechanical transducer. Wave propagation into the liver was analyzed with a phase‐locked spin‐echo sequence at 1.5 T. The viscoelastic parameters, obtained with the Voigt model, were correlated with automatic image analysis of the fibrotic areas and with analysis of the hydroxyproline content of the liver.

Results

Substantial correlations were observed between the shear viscoelastic parameters and the percentage of fibrosis at automatic image analysis (r = 0.7, P = 0.005 for the elasticity, and r = 0.8, P = 0.001 for the viscosity) and moderate correlations were seen between the shear viscoelastic parameters and the hydroxyproline content (r = 0.6, P = 0.016 for the elasticity and r = 0.5, P = 0.041 for the viscosity).

Conclusion

The viscoelastic parameters of the liver measured with in vivo MR elastography correlate with quantitative analysis of liver fibrosis. These results suggest that MR elastography is a promising noninvasive method to quantify liver fibrosis. J. Magn. Reson. Imaging 2007;26:956–962. © 2007 Wiley‐Liss, Inc.
MRI of spontaneous fluctuations after acute cerebral ischemia in nonhuman primates
Authors: Liu Yutong , D'Arceuil Helen , He Julian , Duggan Mike , Gonzalez Gilberto , Pryor Johnny , de Crespigny Alex
Published: September 2007

Purpose

To study the spontaneous low‐frequency blood oxygenation level‐dependent (BOLD) functional MRI (fMRI) signal fluctuations during hyperacute focal cerebral ischemia.

Materials and Methods

A stroke model in nonhuman primates (macaques) was used in this study. Spontaneous fluctuations were recorded using a series of gradient‐recalled echo (GRE) echo‐planar imaging (EPI) images. Fast Fourier transformation (FFT) was performed on the serial EPI data to calculate the frequency and magnitude of the spontaneous fluctuations. Diffusion tensor imaging (DTI) and perfusion‐weighted imaging (PWI) were preformed to detect the ischemic lesion.

Results

The frequency of these fluctuations decreased in the periinfarct tissue in the ipsilateral hemisphere, while their magnitude increased. This area of abnormal signal fluctuations often extended beyond the hyperacute diffusion/perfusion abnormality.

Conclusion

This study suggests that measurement of the spontaneous fMRI signal fluctuations provides different information than is available from diffusion/perfusion or T2‐weighted MRI. J. Magn. Reson. Imaging 2007;26:1112–1116. © 2007 Wiley‐Liss, Inc.
Fragmentation of (LiF)nLi+ clusters in the acceleration region of TOF spectrometers
Authors: Ponciano C. R. , Martinez R. , da Silveira E. F.
Published: September 2007

The binary decay of ionized clusters in the extraction region of time‐of‐flight (TOF) spectrometers is analyzed. The dynamics of the fragments is studied and an analytical expression for the TOF peak shape is deduced; simulations are performed for linear spectrometers of different configurations. The questions addressed refer to the design of TOF spectrometers to improve their accuracy in the determination of metastable‐state mean lives, the identification of precursor masses and the investigation of desorption mechanisms. As an illustration, the method is applied to the decay of positive ion clusters (LiF)nLi+ for both spontaneous and collision‐induced fragmentation processes. No clear evidence of delayed emission is found. The bumps observed in the TOF spectrum are due to tertiary ions emitted by the LiF target sputtered by secondary ions produced in the grid, a process that increases with higher target bias. The main cluster fragmentation observed is (LiF)3Li+* decaying preferentially into (LiF)Li+; the data are compatible with a spontaneous decay of metastable clusters with mean lives of 20–30 ns. Copyright © 2007 John Wiley & Sons, Ltd.
Mass spectrometry and Web 2.0
Authors: Murray Kermit K.
Published: September 2007

The term Web 2.0 is a convenient shorthand for a new era in the Internet in which users themselves are both generating and modifying existing web content. Several types of tools can be used. With social bookmarking, users assign a keyword to a web resource and the collection of the keyword ‘tags’ from multiple users form the classification of these resources. Blogs are a form of diary or news report published on the web in reverse chronological order and are a popular form of information sharing. A wiki is a website that can be edited using a web browser and can be used for collaborative creation of information on the site. This article is a tutorial that describes how these new ways of creating, modifying, and sharing information on the Web are being used for on‐line mass spectrometry resources. Copyright © 2007 John Wiley & Sons, Ltd.
Use of 1‐methylcyclopropene for alleviating chilling injury and lignification of bamboo shoot (Phyllostachys praecox f. prevernalis) during cold storage
Authors: Luo Zisheng , Xu Xiaoling , Yan Bifang
Published: September 2007

BACKGROUND: Bamboo shoot is sensitive to chilling, and low‐temperature injury is a major limitation to its long‐term storage. Studies on the causes of postharvest deterioration in bamboo shoot are few. The aim of the present study was to evaluate the effects of ethylene and 1‐methylcyclopropene (1‐MCP) treatments on the physiological and biochemical responses of bamboo shoot and their ability as a postharvest tool to alleviate chilling injury and lignification of bamboo shoot during storage at 2 °C.

RESULTS: Disease incidence, electrical conductivity (EC), respiration and ethylene production of control bamboo shoot increased after about 2–3 weeks of cold storage, associated with higher chilling injury (CI) index. Increased shoot firmness during cold storage was positively correlated with higher lignin and cellulose accumulation, and this accumulation of lignin in flesh tissue was also positively correlated with the activities of phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD). Ethylene treatment was associated with higher disease incidence, CI index, EC, respiration and ethylene production, enhanced lignin and cellulose accumulation and accelerated the activities of PAL, CAD and POD. In contrast, 1‐MCP treatment was associated with lower respiration, ethylene production, CI index and EC, reduced lignin and cellulose accumulation and retarded the activities of PAL, CAD and POD.

CONCLUSION: The present findings throw light on the role of ethylene in postharvest physiological disorders such as chilling injury and lignification and suggest that 1‐MCP could be used commercially to control these disorders in bamboo shoot during cold storage. Copyright © 2007 Society of Chemical Industry
Polymer Networks in Research and Application
Authors: Burchard Walther
Published: September 2007

Summary: The present review presents an attempt to trace common aspects in the research on networks of very different origin, directed to industrial or biochemical applications. One major feature is the preparation of thermal, pH or ionic sensitive core/ shell structures. These elements proved to be significant in the field of reinforcement of rubbery materials as well as for suitable design of scaffolds for tissue engineering. Striking properties are reveal with examples of thermo‐ and magneto‐sensitive core/shell microgels. Two other instances of oscillating systems are discussed. One was directed to the development of nano‐scaled motors, the other to broadcasting biochemical relevant signals via oscillating Ca++ and H+ ions in vesicle/cytosol systems. Finally problems and progress in scaffold preparation are discussed.
Nanocomposite Gels: New Advanced Functional Soft Materials
Authors: Haraguchi Kazutoshi
Published: September 2007

Summary: Nanocomposite gels (NC gels) consisting of poly(N‐alkylacrylamides) and exfoliated inorganic clay were prepared by in‐situ, free‐radical polymerization at high yield under mild conditions (near ambient temperature, without stirring). Various shapes and different surface forms of NC gels were readily obtained using corresponding vessels and templates, since NC gels were always mechanically tough. The view that polymer/clay networks are formed in NC gels was supported by dynamic viscoelastic and swelling measurements. The entirely different mechanical properties of NC gels, compared with conventional, chemically‐crosslinked hydrogels (OR gels), are discussed on the basis of their network structure. In addition to functions previously reported, NC gels exhibit further interesting characteristics, such as inherent incombustibility, good thermal conductivity, large heat capacity, they can be readily colored and fabricated as foams. NC gels can be utilized as environmentally‐friendly, soft materials from the viewpoints of resources and waste, as their primary component is water.
Programmed Ephemeral Gels: New Types of Biomaterials
Authors: Giraudier Sébastien , Picard Julien , Garde Véronique Larreta
Published: September 2007

Summary: In various biological processes, a solid gel phase is produced which later dissolves. Similar ephemeral protein gels were obtained in vitro using two antagonistic enzymes, one generating and the other cleaving covalent bonds. Alternate sol/gel and gel/sol transitions should occur within such a system, generating transient gel phases. An experimental system consisting of gelatin, transglutaminase and thermolysin was first tested. The various gels obtained were programmed to dissolve after a determined time, without any change in temperature or medium composition, and constitute a completely new type of material which we term “Enzgels”. Varying temperature, but also the protein nature and concentration, the protease specificity, the ratio of the two antagonistic enzymes and, the activity of each enzyme, we were able to generate a full range of ephemeral gels with controlled life times and mechanistic properties.
Bulk High‐Impact Polystyrene Process, 1
Authors: Luciani Carla V. , Estenoz Diana A. , Meira Gregorio R. , García Nancy L. , Oliva Haydée M.
Published: September 2007

In relation to the bulk high‐impact polystyrene process, this work investigates the partition between phases of styrene and an initiator: tert‐butyl peroctoate. A Flory‐Huggins model was applied for predicting the phase separation point and the partitions of styrene and tert‐butyl peroctoate. For blends of styrene, polystyrene, and a styrene‐butadiene diblock copolymer, the model provides reasonable predictions of a ternary equilibrium diagram. For blends of styrene, polystyrene, polybutadiene, and tert‐butyl peroctoate, the partition of tert‐butyl peroctoate was measured at 25 °C. At emulated conversions of 13% or lower, equilibrium was reached after 1 h of mixing time. For the higher molar masses and conversion of 16%, equilibrium was not reached after 24 h of mixing time. To fit the equilibrium measurements, the solubility parameter of tert‐butyl peroctoate was adjusted.

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Subdural motor cortex stimulation in Parkinson's disease does not modify movement‐related rCBF pattern
Authors: Strafella Antonio P. , Lozano Andres M. , Lang Anthony E. , Ko Ji Hyun , Poon Yu‐Yan , Moro Elena
Published: September 2007

There has been some evidence that electrical stimulation of the primary motor cortex (MCS) may relieve motor symptoms of Parkinson's disease (PD). This surgical technique is being studied as alternative for PD patients who are considered poor candidates for deep brain stimulation (DBS) of subthalamic nucleus (STN). In 4 PD patients with unilateral MCS, we used [15O] H2O positron emission tomography to measure changes in regional cerebral blood flow (rCBF) while testing motor performance with a joystick motor task during different stimulation frequencies, OFF‐condition, 50 and 130 Hz. We found that different stimulation settings did neither improve performance on joystick task nor modify the pattern of movement‐related rCBF. Similarly, no changes were observed in UPDRS motor score between Off and On stimulation while off medication. We conclude that while MCS may be a simpler and safer surgical procedure than DBS of STN, it failed to provide evidence of clear effect on motor performance and movement‐related activation pattern in patients with advanced PD. © 2007 Movement Disorder Society
Comparison of brain MRI and 18F‐FDG PET in the differential diagnosis of multiple system atrophy from Parkinson's disease
Authors: Kwon Kyum‐Yil , Choi Choong G. , Kim Jae S. , Lee Myoung C. , Chung Sun J.
Published: September 2007

To investigate the diagnostic value of brain magnetic resonance image (MRI) and 18F‐fluorodeoxyglucose positron emission tomography (18F‐FDG PET) in the differentiation of multiple system atrophy (MSA) from Parkinson's disease (PD). Thirty‐five patients with MSA (23 MSA‐P and 12 MSA‐C) and 17 patients with PD were included in this study. Overall correct diagnosis rates between clinical and imaging diagnosis among MSA‐P, MSA‐C, and PD patients were 80% for visual MRI analysis, 88.5% for visual 18F‐FDG PET analysis, and 84.3% for SPM‐supported analysis of 18F‐FDG PET. The sensitivity of brain MRI, and visual and SPM analysis of 18F‐FDG PET in differentiating MSA from PD was 72.7%, 90.9%, and 95.5%, respectively, the specificity was 100% for each imaging analysis, the positive predictive value was 100% for each imaging analysis, and the negative predictive value was 60%, 81.8%, and 90%, respectively. Our results suggest that brain MRI and 18F‐FDG PET are diagnostically useful in differentiating MSA (MSA‐P and MSA‐C) from PD, and indicate that 18F‐FDG PET has a tendency toward higher sensitivity compared to brain MRI, but a larger longitudinal study including pathological data will be required to confirm our findings. © 2007 Movement Disorder Society
Short‐term continuous infusion of apomorphine hydrochloride for treatment of Huntington's chorea: A double blind, randomized cross‐over trial
Authors: Vitale Carmine , Marconi Stefano , Di Maio Luigi , De Michele Giuseppe , Longo Katia , Bonavita Vincenzo , Barone Paolo
Published: September 2007

We evaluated tolerability and the efficacy of continuous infusion of apomorphine hydrochloride on involuntary movements and mood disorder in Huntington's disease (HD) patients in a pilot, single center, double‐blind, randomized, crossover, and controlled versus placebo study. Nine patients with a molecular diagnosis of HD were screened for response to acute apomorphine injection. Four of them, not ameliorating at the acute test, were discontinued. Five patients, responding to acute apomorphine, received continuous infusion of either apomorphine or placebo for 5 days. After 2 days of washout, the alternative treatment was administered. Primary endpoint measures were scores of the Unified Huntington's Disease Rating Scale (UHDRS “motor section”) and of the Abnormal Involuntary Movement Scale (AIMS). Secondary endpoint measures were the Hamilton Depression Rating Scale (HAD) score and safety parameters. Both UHDRS and AIMS scores significantly decreased in all patients after apomorphine. The beneficial effect of apomorphine was recorded throughout the 5 treatment days. The HAD score did not change after infusion of either treatment. No serious adverse events were reported by either group during the study. Our results suggest that continuous infusion of apomorphine might be considered for the treatment of involuntary movements in some HD patients. © 2007 Movement Disorder Society
Decreased cortical inhibition and yet cerebellar pathology in ‘familial cortical myoclonic tremor with epilepsy’
Authors: van Rootselaar Anne‐Fleur , van der Salm Sandra M.A. , Bour Lo J. , Edwards Mark J. , Brown Peter , Aronica Eleonora , Rozemuller‐Kwakkel Johanna M. , Koehler Peter J. , Koelman Johannes H.T.M. , Rothwell John C. , Tijssen Marina A.J.
Published: September 2007

Cortical hyperexcitability is a feature of “familial cortical myoclonic tremor with epilepsy” (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar Purkinje cell degeneration and a normal sensorimotor cortex. Subsequently, we sought to explore the nature of cerebellar and motor system pathophysiology in FCMTE. Eye movement recordings and transcranial magnetic stimulation performed in six related FCMTE patients showed impaired saccades and smooth pursuit and downbeat nystagmus upon hyperventilation, as in patients with spinocerebellar ataxia type 6. In FCMTE patients short‐interval intracortical inhibition (SICI) was significantly reduced. Resting motor threshold, recruitment curve, silent period, and intracortical facilitation were normal. The neuropathological and ocular motor abnormalities indicate cerebellar involvement in FCMTE patients. Decreased SICI is compatible with intracortical GABAA‐ergic dysfunction. Cerebellar and intracortical functional changes could result from a common mechanism such as a channelopathy. Alternatively, decreased cortical inhibition may be caused by dysfunction of the cerebello‐thalamo‐cortical loop as a result of primary cerebellar pathology. © 2007 Movement Disorder Society
The REM sleep behavior disorder screening questionnaire—A new diagnostic instrument
Authors: Stiasny‐Kolster Karin , Mayer Geert , Schäfer Sylvia , Möller Jens Carsten , Heinzel‐Gutenbrunner Monika , Oertel Wolfgang H.
Published: September 2007

Many patients with assumed idiopathic REM sleep behavior disorder (RBD) may actually represent an early clinical manifestation of an evolving neurodegenerative disorder, such as the α‐synucleinopathies, Parkinson's disease or multiple system atrophy. Early detection of these patients is clinically relevant for long‐term prospective as well as future neuroprotective studies. For this purpose, we validated a 10‐item patient self‐rating questionnaire (maximum total score 13 points) covering the clinical features of RBD. The RBD screening questionnaire (RBDSQ) was applied to 54 patients with polysomnographically confirmed RBD (29 men; mean age 53.7 ± 15.8 years), 160 control subjects (81 men; mean age 50.8 ± 15.5 years) in whom RBD was excluded by history and polysomnography (PSG, control group 1) and 133 unselected healthy subjects (58 men; mean age 46.9 ± 12.3 years; no PSG, control group 2). In most subjects (n = 153) of control group 1, other sleep‐wake disturbances were present. The mean RBDSQ score in the RBD group was 9.5 ± 2.8 points compared with 4.6 ± 3.0 points in control group 1 (P < 0.0001). Considering an RBDSQ score of five points as a positive test result, we found a sensitivity of 0.96 and a specificity of 0.56. The RBDSQ poorly discriminated patients with the most challenging differential diagnoses such as sleepwalking or epilepsy. In control group 2, the mean RBDSQ score (2.02 ± 1.78) was significantly lower than in the RBD group (P < 0.0005), revealing a specificity of 0.92. Due to its high sensitivity, the RBDSQ appears to be particularly useful as a screening tool. © 2007 Movement Disorder Society
Towards a resource management and service deployment framework
Authors: Chrysoulas Christos , Haleplidis Evangelos , Kostopoulos Giorgos , Haas Robert , Koufopavlou Odysseas
Published: September 2007

Owing to the increase in both heterogeneity and complexity in today's networking systems, the need arises for new network‐based services architectures. They must provide flexibility and efficiency in the definition, deployment and execution of the services and, at the same time, handle the adaptability and evolution of such services. In this paper we present an approach that applies a Web‐service‐based resource management framework. It enables the provision of parallel applications as QoS‐aware applications, whose performance characteristics may be dynamically negotiated between a client application and service providers. Our component model allows context dependencies to be explicitly expressed and dynamically managed with respect to the hosting environment, computational resources and dependencies on other components. In such a model the resource management, in terms of representation, allocation and management of the resources, plays a vital role regarding the efficiency of the entire dynamic service deployment architecture. Copyright © 2007 John Wiley & Sons, Ltd.