bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water use and productivity of two small reservoir irrigation schemes in Ghana's upper east region
Authors: Faulkner Joshua W. , Steenhuis Tammo , van de Giesen Nick , Andreini Marc , Liebe Jens R. 
Published: March 2008

AbstractTo examine the impact of small reservoir irrigation development in Africa, the performance and productivity of two small reservoirs and irrigation schemes in the Upper East Region of Ghana were investigated in this study. Hydrologic data measured included daily irrigation volumes and daily evaporation. Farmer cost inputs, excluding labor, and harvest data were also recorded. There was a strong contrast in water availability between the two systems, the Tanga system having a higher amount of available water than did the Weega system. The concept of relative water supply was used to confirm this disparity; Tanga was an inefficient system with a relative water supply of 5.7, compared to a value of 2.4 for the efficient Weega system. It was also concluded that the dissimilar water availabilities resulted in the evolution of very different irrigation methods and coincided with different management structures. Where there was more water available per unit land (Tanga), management was relaxed and the irrigation inefficient. Where there was less water available per unit land (Weega), management was well structured and irrigation efficient. The productivity of water (US$ m−3) of the Tanga system was half that of the Weega system, when analyzed at a high market price for crops grown. In terms of productivity of cultivated land (US$ ha−1), however, the Tanga system was 49% more productive than the Weega system. The difference in the productivity of land is primarily a result of increased farmer cash inputs in the Tanga system as compared to the Weega system. The difference in the productivity of water can be attributed to the varying irrigation methods and management structures, and ultimately to the contrasting water availability. Copyright © 2008 John Wiley & Sons, Ltd.
Source of low‐frequency fluctuations in functional MRI signal
Authors: Razavi Mehrdad , Eaton Brent , Paradiso Sergio , Mina Mani , Hudetz Anthony G. , Bolinger Lizann 
Published: March 2008

AbstractPurposeTo investigate the source of native low‐frequency fluctuations (LFF) in functional MRI (fMRI) signal.Materials and MethodsPhase analysis was performed on tissue‐segmented fMRI data acquired at systematically varying sampling rates.ResultsLFF in fMRI signal were both native and aliased in origin. Scanner instability did not contribute to native or aliased LFF. Aliased LFF arose from cardiorespiratory processes and head motion. Native LFF did not arise from cardiorespiratory processes, but did so, at least in part, from head motion. Motion correction reduced native LFF, but did not eliminate them. The residual native LFF in motion‐corrected fMRI data showed a systematic phase difference among different tissue structures. The native LFF in fMRI signals of cerebral blood vessels and CSF were synchronous, and preceded those of gray and white matter, indicating that the vascular fluctuations lead the metabolic fluctuations.ConclusionThe primary physiologic source of native LFF in fMRI signal is vasomotion. J. Magn. Reson. Imaging 2008;27:891–897. © 2008 Wiley‐Liss, Inc.
Relationship between choline and apparent diffusion coefficient in patients with gliomas
Authors: Khayal Inas S. , Crawford Forrest W. , Saraswathy Suja , Lamborn Kathleen R. , Chang Susan M. , Cha Soonmee , McKnight Tracy R. , Nelson Sarah J. 
Published: March 2008

AbstractPurposeTo examine the relationship between apparent diffusion coefficients (ADC) from diffusion weighted imaging (DWI) and choline levels from proton magnetic resonance spectroscopic imaging (MRSI) in newly diagnosed Grade II and IV gliomas within distinct anatomic regions.Materials and MethodsA total of 37 patients with Grade II and 28 patients with Grade IV glioma were scanned on a 1.5T system with 3D MRSI and DWI. Region level analysis included Spearman rank correlation between median normalized ADC and choline for each patient per grade within each distinct abnormal anatomical region. Voxel level analysis calculated a Spearman rank correlation per region, per patient.ResultsGrade II lesions showed no evidence of a correlation between normalized ADC and choline using either the region or voxel level analysis. Region level analysis of Grade IV lesions did not appear to correlate in the contrast enhancement or necrotic core, but did suggest a significant negative correlation in the more heterogeneous nonenhancing and combined regions.ConclusionThere appears to be differences in the relationship between ADC and choline levels in Grade II and Grade IV gliomas. Correlation within these regions in Grade IV lesions was strongest when all regions were included, suggesting heterogeneity may be driving the relationship. J. Magn. Reson. Imaging 2008;27:718–725. © 2008 Wiley‐Liss, Inc.
Contrast‐enhanced MRI of murine sponge model for progressive angiogenesis assessed with gadoteridol (ProHance) and gadocoletic acid trisodium salt (B22956/1)
Authors: Ramponi Simona , Rebaudengo Cristina , Cabella Claudia , Grotti Adriana , Vultaggio Stefania , Aime Silvio , Morisetti Alberto , Lorusso Vito 
Published: March 2008

AbstractPurposeTo investigate the potential value of MRI for noninvasive assessment of angiogenesis in a murine model exploiting the properties of two contrast agents, gadoteridol (ProHance) and gadocoletic acid trisodium salt (B22956/1).Materials and MethodsBiocompatible sponges were implanted in both mice flanks. Stimulated sponges contained human recombinant basic fibroblast growth factor (bFGF) as the angiogenic agent; control sponges contained vehicle. Angiogenesis was evaluated by MRI after injection of extravascular (ProHance) or blood‐pool (B22956/1) contrast agents at different times after sponge implantation. Sponges signal intensity enhancement was calculated both as the relative enhancement and the rate of relative enhancement. Results from MRI were validated by classic biochemical (hemoglobin level and protein content) and morphological (histology) assays.ResultsThe intrinsic different properties of ProHance and B22956/1 in wash‐in and wash‐out kinetics were useful to detect progressive vascularization and the establishment of a functional vascular network in the implants. Moreover, MRI allowed the appreciation of differences in neovessel colonization between bFGF‐treated sponges and controls. Hemoglobin level, protein content, and histology confirmed the sponge vascularization and MRI results.ConclusionContrast‐enhanced MRI is a reliable tool to study vascular characteristics in animal models of angiogenesis. The different kinetic properties of contrast agents can provide evidence of different functional neovascularization aspects and levels. J. Magn. Reson. Imaging 2008;27:872–880. © 2008 Wiley‐Liss, Inc.
Simultaneous imaging of myocardial motion and chamber blood flow with SPAMM n' EGGS (spatial modulation of magnetization with encoded gradients for gauging speed)
Authors: Sampath Smita , Kim June H. , Lederman Robert J. , McVeigh Elliot R. 
Published: March 2008

AbstractPurposeTo provide simultaneous measurements of one‐dimensional (1‐D) myocardial displacement and 1‐D chamber blood flow in a single breath‐held acquisition using an MR imaging technique, SPAMM n' EGGS (Spatial Modulation of Magnetization With Encoded Gradients for Gauging Speed).Materials and MethodsVelocity encoding bipolar gradients sensitive to chamber blood flow were played out before the readout gradient in a 1‐1 SPAMM‐tagged MR imaging pulse sequence. For any given motion–flow encoded direction, the acquired image sequence was later postprocessed to separate the tag motion and blood flow terms. Experiments were performed on seven normal volunteers, and two pigs with moderate ischemic mitral regurgitation. Left‐ventricular motion and trans‐valvular flow obtained using the SPAMM n' EGGS pulse sequence was compared against measurements obtained using standard tagging and phase‐contrast pulse sequences, respectively.ResultsResults in normal volunteers and diseased pigs demonstrate multiphase correlated measurements of myocardial motion and chamber blood flow using SPAMM n' EGGS. A close correspondence in these measurements to conventional tagging and phase‐contrast sequences is confirmed.ConclusionWe have demonstrated that simultaneous acquisition of myocardial motion and chamber blood flow is possible within a single breath‐hold. The data obtained using the SPAMM n' EGGS pulse sequence may be useful in the planning and evaluation of mitral‐valve repair procedures. J. Magn. Reson. Imaging 2008;27:809–817. © 2008 Wiley‐Liss, Inc.
Quantification of MRI measured myocardial perfusion reserve in healthy humans: A comparison with positron emission tomography
Authors: Fritz‐Hansen Thomas , Hove Jens D. , Kofoed Klaus F. , Kelbaek Henning , Larsson Henrik B.W. 
Published: March 2008

AbstractPurposeTo validate a noninvasive quantitative MRI technique, the Ki perfusion method, for myocardial perfusion in humans using 13N‐ammonia PET as a reference method.Materials and MethodsTen healthy males (64 ± 8 years) were examined with combined PET and MRI perfusion imaging at rest and during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd‐DTPA‐enhanced MRI and 13N‐ammonia PET were fitted by a two‐compartment perfusion model.ResultsMean perfusion values (±SD) derived from the MRI method at rest and at hyperemia were 80 ± 20 and 183 ± 56 mL/min/100 g, respectively. The same data for PET were 71 ± 16 and 203 ± 67 mL/min/100 g. A linear relationship was observed between MRI and PET‐derived myocardial perfusion reserve for regional and global data. Linear regression for the global absolute perfusion reserve gave a correlation coefficient of 0.96 (P < 0.004, y=0.83x‐6.9). A good agreement between the two methods to determine low or high perfusion reserves was found.ConclusionOur data provide validation of the perfusion marker Ki derived by the MRI method as a quantitative marker for myocardial perfusion in healthy humans. J. Magn. Reson. Imaging 2008;27:818–824. © 2008 Wiley‐Liss, Inc.
Local re‐inversion coronary MR angiography: Arterial spin‐labeling without the need for subtraction
Authors: Katoh Marcus , Spuentrup Elmar , Barmet Christoph , Stuber Matthias 
Published: March 2008

AbstractPurposeTo implement a double‐inversion bright‐blood coronary MR angiography sequence using a cylindrical re‐inversion prepulse for selective visualization of the coronary arteries.Materials and MethodsLocal re‐inversion bright‐blood magnetization preparation was implemented using a nonselective inversion followed by a cylindrical aortic re‐inversion prepulse. After an inversion delay that allows for in‐flow of the labeled blood‐pool into the coronary arteries, three‐dimensional radial steady‐state free‐precession (SSFP) imaging (repetition/echo time, 7.2/3.6 ms; flip angle, 120°, 16 profiles per RR interval; field of view, 360 mm; matrix, 512, twelve 3‐mm slices) is performed. Coronary MR angiography was performed in three healthy volunteers and in one patient on a commercial 1.5 Tesla whole‐body MR System.ResultsIn all subjects, coronary arteries were selectively visualized with positive contrast. In addition, a middle‐grade stenosis of the proximal right coronary artery was seen in one patient.ConclusionA novel T1 contrast‐enhancement strategy is presented for selective visualization of the coronary arteries without extrinsic contrast medium application. In comparison to former arterial spin‐labeling schemes, the proposed magnetization preparation obviates the need for a second data set and subtraction. J. Magn. Reson. Imaging 2008;27:913–917. © 2008 Wiley‐Liss, Inc.
Estrogen receptor and breast MR imaging features: A correlation study
Authors: Chen Jeon‐Hor , Baek Hyeon‐Man , Nalcioglu Orhan , Su Min‐Ying 
Published: March 2008

AbstractPurposeTo compare the MRI features between estrogen receptor (ER) positive and negative breast cancers.Materials and MethodsBreast MRI of 90 consecutive patients confirmed with invasive ductal carcinoma (IDC), 51 ER positive and 39 ER negative, were analyzed. The tumor morphology and dynamic contrast‐enhanced (DCE) kinetics were evaluated based on the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI‐RADS) MRI lexicon and compared. Enlarged axillary lymph nodes on MRI and choline (Cho) detection using MR spectroscopy (MRS) were also analyzed and compared. For patients receiving axillary node dissection the pathological nodal status was also compared.ResultsER negative breast cancer had bigger tumors compared to ER positive cancer (3.6 ± 2.0 cm vs. 1.8 ± 1.3 cm, P < 0.00005). ER negative cancer was more likely to exhibit nonmass type enhancements compared to ER positive cancer (P < 0.005). Enlarged axillary lymph nodes were more frequently identified on MRI in ER negative compared to ER positive patients (P < 0.05). After excluding patients undergoing neoadjuvant chemotherapy, axiliary lymph node status did not show significant difference between ER positive and ER negative cancer on MRI and pathology. ER negative cancer was more likely to show the malignant type enhancement kinetics (P = 0.15), rim enhancement (P = 0.15), and Cho detection on MRS (P = 0.23) compared to ER positive cancer, but it did not reach a level of statistical significance.ConclusionER negative breast cancer was more aggressive, with larger tumor size, more non‐mass‐type enhancement lesions, and a higher percentage showing enlarged axillary nodes on MRI. These features might be related to its poorer cellular differentiation and/or a higher angiogenesis. J. Magn. Reson. Imaging 2008;27:825–833. © 2008 Wiley‐Liss, Inc.
Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C–valine isotopic ratios in complex biological samples
Authors: Godin Jean‐Philippe , Breuillé Denis , Obled Christiane , Papet Isabelle , Schierbeek Henk , Hopfgartner Gérard , Fay Laurent‐Bernard 
Published: March 2008

AbstractOn‐line gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high‐precision 13C isotopic enrichment can also be measured by liquid chromatography‐isotope ratio mass spectrometry (LC‐IRMS). Indeed, LC‐IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure 13C isotopic enrichment of underivatised amino acids (Asp, Thr–Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(δ13C) reported with this method was found to be below 1‰ . Another key feature of the new LC‐IRMS method reported in this paper is the comparison of the LC‐IRMS approach with the conventional GC‐C‐IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)‐ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (δ13C = − 12.3 to 150.8‰), the calculated root‐mean‐square (rms) of SD was 0.38 and 0.46‰ and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC‐C‐IRMS and LC‐IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (δ13C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC‐C‐IRMS and LC‐IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC‐C‐IRMS and LC‐IRMS instruments were also used to assess isotopic enrichment of protein‐bound 13C–Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC‐IRMS and GC‐C‐IRMS were not statistically different (p > 0.05). The results of this work indicate that the LC‐IRMS was successful for high‐precision 13C isotopic measurements in tracer studies giving 13C isotopic enrichment similar to the GC‐C‐IRMS but without the step of GC derivatisation. Therefore, for clinical studies requiring high‐precision isotopic measurement, the LC‐IRMS is the method of choice to measure the isotopic ratio. Copyright © 2008 John Wiley & Sons, Ltd.
Mycoflora associated withHyoscyamus muticusgrowing under an extremely arid desert environment (Aswan region, Egypt)
Authors: El‐Zayat Soad A. , Nassar Mortada S. M. , El‐Hissy Farida T. , Abdel‐Motaal Fatma F. , Ito Shin‐ichi 
Published: March 2008

AbstractHyoscyamus muticusL. (Egyptian henbane) is one of the desert medicinal plants of family Solanaceae. The plant produces pharmaceutically important compounds (tropane alkaloids) as secondary metabolites. In the present study, we describe mycoflora ofH. muticusgrown in four different locations in Egyptian southern desert (Aswan region): Aswan university campus, Wadi Allaqi down stream part, Aswan airport road, and Sahari city. Eighty‐one species and two varieties belonging to 31 genera were isolated from soils surroundingH. muticusplants, the surface of the plants, and inside the plants as endophytic fungi.Aspergilluswas the most common genus in all study areas. The highest number of genera and species of fungi were recorded in Aswan university campus followed by Aswan airport road. Fungal diversity analysis revealed that these two locations have higher fungal diversity compared to other two locations. A higher number of fungal species were isolated from rhizosphere soil and rhizoplane than from non‐rhizosphere and other plant organs. Endophytic fungi were isolated from all plant parts ofH. muticus.Communications betweenH. muticusplants and fungi under desert conditions both in rhizosphere and inside the plant are deduced. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screening of Aspergillus species for occurrence of lectins and their characterization
Authors: Singh Ram Sarup , Tiwary Ashok Kumar , Bhari Ranjeeta 
Published: March 2008

AbstractTen species of Aspergillus were screened for occurrence of lectins. Each of the species was investigated for the occurrence of extracellular, surface‐bound and intracellular lectin activities. As many as four species namely, Aspergillus niger, Aspergillus versicolor, Aspergillus rugulosus and Aspergillus nidulans, were found to possess intracellular lectin activities, while none of the species showed extracellular or surface‐bound lectin activities. Each of the lectin was characterized with respect to blood group and carbohydrate specificities. All the lectins were found to agglutinate human erythrocytes, irrespective of their blood group and pig erythrocytes. However, they did not show agglutination with sheep or goat erythrocytes. Of the various carbohydrates tested, all lectins were found to be specific for inulin, mucin, asialofetuin, N‐acetyl galactosamine, melibiose, D‐ribose, L‐fucose, D‐arabinose, D‐sucrose and D‐mannitol. The minimum inhibitory concentration of each of the specific sugars was also determined. The lectins were partially purified using ammonium sulfate precipitation technique. Each of the lectin was found to be precipitated at 40–50% saturation of ammonium sulfate, yielding about 80% of lectin activity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new spiroketal from Aspergillus terreus, an endophytic fungus in Opuntia ficusindica Mill
Authors: Wu Shao‐Hua , Chen You‐Wei , Qin Sheng , Huang Rong 
Published: March 2008

AbstractA new spiroketal, named aspergiketal (1) was isolated from the culture broth of Aspergillus terreus, an endophytic fungus in the stems of the plant Opuntia ficusindica Mill., together with two known compounds, physcion (2) and asterric acid (3). Their structures were elucidated by spectroscopic methods including 2D‐NMR techniques. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supercritical fluid extraction of cynaropicrin and 20‐hydroxyecdysone from Leuzea carthamoides DC
Authors: Sovová Helena , Opletal Lubomír , Sajfrtová Marie , Bártlová Milena 
Published: March 2008

AbstractLeuzea carthamoides is an adaptogenic plant containing biologically active compounds as ecdysteroids and guaianolide‐type sesquiterpene lactones, conventionally extracted from the plant with ethanol. It may be a potential source of the mentioned natural compounds. Ethanol‐modified near‐critical CO2 was used as selective solvent with the aim to increase the level of 20‐hydroxyecdysone in the extract from L. carthamoides roots and to remove selectively cynaropicrin, a sesquiterpene lactone of bitter taste, from the leaves. The extraction conditions were varied (pressure 20–28 MPa, temperature 40–60°C, ethanol concentration in the solvent 0–7.1%) and the extraction yield and extract composition were compared with the results of ethanolic extraction. The supercritical fluid extraction (SFE) from finely powdered plant was controlled by phase equilibrium. Cynaropicrin was quantitatively removed from the leaves where 89% of 20‐hydroxyecdysone was retained. The extraction yield of 20‐hydroxyecdysone from roots with ethanol‐modified CO2 was lower by 30% than with ethanol but its concentration in the extract was higher by 67%.
Light propagation in multi‐step index optical fibres
Authors: Zubia J. , Aldabaldetreku G. , Durana G. , Arrue J. , Jiménez F. 
Published: March 2008

AbstractThis paper reviews the theoretical analysis of light propagation we have carried out on multimode multi‐step index (MSI) optical fibres. Starting from the Eikonal equation, we derive the analytical expressions that allow calculating the ray trajectories inside these fibres. We also analyse the effects of leaky rays on the transmission properties of MSI fibres. For this purpose, a single analytical expression for the evaluation of the ray power transmission coefficient is calculated. Afterwards, we investigate the effects of extrinsic and intrinsic coupling losses on the performance of MSI fibres, providing analytical expressions to calculate the coupling loss and, also, determining the most critical parameters. Finally, we carry out a comprehensive numerical analysis of the fibre bandwidth under different source configurations.
Potential and limitations of laser technology in restoration of metallic objects of art and cultural heritage
Authors: Klotzbach U. , Panzner M. , Wiedemann G. 
Published: March 2008

AbstractPotential applications of laser techniques, such as precision cutting, micro welding, and ablation of stains, are presented. Concerning laser beam ablation, we explain the mechanism, and then discuss potential applications (cleaning of gilded or solid metal surfaces, cleaning of verdigris) and limits (thinning of verdigris, removing rust from verdigris). This research has been performed within the frame of a joint project sponsored by Deutsche Bundesstiftung Umwelt (DBU, German Foundation for the Environment) as well as in immediate co‐operation with restorers. The presentation of these results is to propose laser technology as a promising option to be taken into account in planning and doing restoratory work.