bluuebunny/crossref_metadata_2025_split huggingface dataset:
Filtered deconvolution of a simulated and an in vivo phase model of the human brain
Authors: Grabner Günther , Trattnig Siegfried , Barth Markus 
Published: July 2010

AbstractPurpose:To remove spatial patterns in gradient echo phase images which are caused by susceptibility differences between different tissue types using filtered deconvolution and to evaluate deconvolution effects.Materials and Methods:A realistic simulated susceptibility map of the human brain was built and used to evaluate the effects of filtered deconvolution. The simulated susceptibility map was convolved with a filter kernel representing a magnetic dipole resulting in a simulated phase map. The artificial phase map was superimposed with different noise levels and deconvolved using different deconvolution kernels. The resulting contrast‐to‐noise ratios between white and gray matter of the deconvolved data provide an estimate for an optimal deconvolution kernel for a given noise level. These results were used to deconvolve an in vivo phase model representing the average of 30 phase data sets and also individual phase data acquired at 7 Tesla.Results:The deconvolved phase model shows a better anatomical agreement with the corresponding magnitude than the original phase model (5% higher κ coefficient). Visual inspection of the deconvolved individual phase shows a more consistent delineation of blood vessels.Conclusion:Filtered deconvolution of SWI phase is possible when an appropriate filter kernel is used. This helps to improve region of interest definition as unrealistic phase patterns are removed. J. Magn. Reson. Imaging 2010;32:289–297. © 2010 Wiley‐Liss, Inc.
Intra‐renal oxygenation in rat kidneys during water loading: Effects of cyclooxygenase (COX) inhibition and nitric oxide (NO) donation
Authors: Ji Lin , Li Lu‐Ping , Schnitzer Thomas , Du Hongyan , Prasad Pottumarthi V. 
Published: July 2010

AbstractPurpose:To evaluate intra‐renal oxygenation by blood oxygenation level dependent (BOLD) MRI in rat kidneys during water loading and to investigate if the NO donating moiety in naproxcinod could compensate for the effect of cyclooxygenase (COX) inhibition of naproxen.Materials and Methods:Nineteen male Sprague Dawley rats were divided into three groups and dosed with vehicle, naproxen or naproxcinod by gavage for two weeks. On the day of the experiment, hypotonic saline with glucose was infused intravenously to induce water diuresis. BOLD MRI data to monitor renal oxygenation and timed urine samples for estimation of prostaglandins (PGs) and urine flow were obtained.Results:The data in this study is consistent with previous experience in humans in that pre‐treatment with naproxen abolished the improvement in medullary oxygenation during water loading. In addition, the inhibition of PGs by naproxcinod reached similar levels as naproxen but maintained the improvement in oxygenation in renal medulla during water loading.Conclusion:This suggests that naproxcinod may have less nephrotoxicity and that the NO donating moiety partially compensates for the hemodynamic effects of prostaglandin inhibition by naproxen. J. Magn. Reson. Imaging 2010;32:383–387. © 2010 Wiley‐Liss, Inc.
Comparison of the high relaxivity Gd chelates P1152 and Gd‐BOPTA for contrast‐enhanced MR angiography in rabbits at 1.5 Tesla and 3.0 Tesla
Authors: Peldschus Kersten , Hamdorf Mareike , Robert Philippe , Port Marc , Adam Gerhard , Herborn Christoph U. 
Published: July 2010

AbstractPurpose:To compare signal‐enhancing properties of the high relaxivity Gd chelates P1152 and Gd‐BOPTA for contrast‐enhanced MR angiography (CE‐MRA) in rabbits at 1.5 Tesla (T) and 3.0T.Materials and Methods:Three‐dimensional CE‐MRA of the abdominal vasculature was performed in six rabbits using both contrast agents at a dose of 0.1 mmol/kg. Data acquisition was carried out during first pass and up to 10 min after contrast material administration. CNR was determined in aorta, vena cava, and renal cortex. Image quality (5‐point scale, 5 = best) of first pass MR angiograms was rated by two radiologists.Results:During first pass CNR of the aorta was 55.1 ± 5.8 (P1152) and 40.3 ± 3.9 (Gd‐BOPTA) at 1.5T (P < 0.05), and 114.9 ± 9.9 (P1152) and 73.5 ± 8.1 (Gd‐BOPTA) at 3.0T (P < 0.05). Both contrast agents showed a comparable decline of CNR within 10 min. Image quality was rated 4.8 ± 0.40 (P1152) and 4.5 ± 0.50 (Gd‐BOPTA) at 1.5T (P = 0.17), and 4.8 ± 0.37 (P1152) and 4.7 ± 0.47 (Gd‐BOPTA) at 3.0T (P = 0.61).Conclusion:The high relaxivity Gd‐chelate P1152 offers potential to improve image contrast for CE‐MRA compared with a clinically approved high relaxivity contrast agent. J. Magn. Reson. Imaging 2010;32:459–465. © 2010 Wiley‐Liss, Inc.
Individual voxel‐based analysis of brain magnetization transfer maps shows great variability of gray matter injury in the first stage of multiple sclerosis
Authors: Jure Lorena , Zaaraoui Wafaa , Rousseau Celia , Reuter Françoise , Rico Audrey , Malikova Irina , Confort‐Gouny Sylviane , Cozzone Patrick J. , Pelletier Jean , Ranjeva Jean‐Philippe , Audoin Bertrand 
Published: July 2010

AbstractIn multiple sclerosis (MS), it seems likely that the variability of the long‐term disability might be partly due to the variability of the early gray matter (GM) injury. In the present study, we assessed the variability of GM injury in early MS, using a method designed to determine individual pathological GM patterns. Eighteen patients presenting with a clinically isolated syndrome and 24 healthy matched control subjects were included in this study. Patients were explored using a 1.5 Tesla MR scanner (Magnetom Vision Plus; Siemens). Brain MR protocol included magnetization transfer ratio imaging (MTR). Statistical mapping analyses were performed to compare each subject's GM MTR maps with those of the whole group of control subjects (SPM5). The statistical threshold was taken to be the maximum P value showing no significant cluster when any control individual was compared with the whole control population. GM abnormalities were observed in 83% of the patients, ranging in size from 0.3 to 125 cm3. Among the patients with GM abnormalities, 87% had abnormalities located in the temporal cortex, 80% in the frontal cortex, 80% in the limbic cortex, 73% in the posterior fossa, 53% in the deep GM, 47% in the parietal cortex, and 47% in the occipital cortex. Individual statistical mapping of MTR data, which gives a quantitative assessment of individual GM lesions, demonstrates great variability of grey matter injury in the first stage of multiple sclerosis. J. Magn. Reson. Imaging 2010;32:424–428. © 2010 Wiley‐Liss, Inc.
Value of delayed hypointensity and delayed enhancing rim in magnetic resonance imaging diagnosis of small hepatocellular carcinoma in the cirrhotic liver
Authors: Khan Asra S. , Hussain Hero K. , Johnson Timothy D. , Weadock William J. , Pelletier Shawn J. , Marrero Jorge A. 
Published: July 2010

AbstractPurpose:To determine the diagnostic utility of delayed hypointensity and delayed enhancing rim on magnetic resonance imaging (MRI) as indicators of hepatocellular carcinoma (HCC) in arterially enhancing nodules ≤5 cm in the cirrhotic liver and determine the features that best predict HCC.Materials and Methods:Gadolinium‐enhanced MRI studies performed from January 2001 to December 2004 in patients with cirrhosis were evaluated for arterially enhancing nodules measuring ≤5 cm. Verification was via explant correlation, biopsy, or imaging follow‐up. Sensitivity and specificity of diagnostic features of HCC were calculated. Features predictive of HCC were determined using the Generalized Estimating Equation approach.Results:In all, 116 arterially enhancing nodules were identified in 80 patients (<2 cm: n = 79, 2–5 cm n = 37). Sensitivity and specificity of delayed hypointensity for HCC measuring ≤5 cm, 2–5 cm, and <2 cm were 0.54 (40 of 74) and 0.86 (36 of 42); 0.72 (23 of 32) and 0.80 (4 of 5); and 0.41 (17 of 42) and 0.87 (32 of 37). For the delayed enhancing rim sensitivity and specificity were 0.64 (47 of 74) and 0.86 (36 of 42); 0.75 (24 of 32) and 1.0 (5 of 5); and 0.55 (23 of 42) and 0.83 (31 of 37), respectively. Lesion size (≥2 cm) and delayed enhancing rim, as main features and their interaction, were the most significant predictors of HCC.Conclusion:Delayed hypointensity and enhancing rim improve the specificity of diagnosis of HCC of all sizes but are seen less frequently in small (<2 cm) HCC. Nodule size (≥2 cm) and delayed enhancing rim are the strongest predictors of HCC. J. Magn. Reson. Imaging 2010;32:360–366. © 2010 Wiley‐Liss, Inc.
Effective use of flow‐spoiled FBI and time‐SLIP methods in the diagnostic study of an aberrant vessel of the head and neck: “Left jugular venous steal by the right jugular vein”
Authors: Kogure Taroh , Kogure Kyuya , Iizuka Mitsumasa , Ino Azusa , Ishii Masako 
Published: July 2010

AbstractThree‐dimensional (3D) time‐of‐flight (TOF) is now commonly used in routine magnetic resonance angiography (MRA) studies of the head and neck. However, there are limits to its diagnostic abilities in the clinical field and, in some instances, a more invasive supplementary examination may be required. We incidentally discovered a patient with an aberrant vessel of the head and neck that ran alongside the left carotid artery and contained a constant, slowly pulsating efferent blood flow. 3D‐TOF and carotid ultrasonography could not determine the nature and origin of this vessel. Additional studies using flow‐spoiled fresh blood imaging (flow‐spoiled FBI) and time spatial labeling inversion pulse (time‐SLIP) methods were effective in determining that the vessel was the left jugular vein, and that the continuous venous reflux was a result of a venous steal by the right jugular vein. We show that by combining different MRA techniques we can effectively achieve diagnosis without resorting to more invasive examinations. J. Magn. Reson. Imaging 2010;32:429–433. © 2010 Wiley‐Liss, Inc.
Efficient flow suppressed MRI improves interscan reproducibility of carotid atherosclerosis plaque burden measurements
Authors: Dong Li , Wang Jinnan , Yarnykh Vasily L. , Underhill Hunter R. , Neradilek Moni B. , Polissar Nayak , Hatsukami Thomas S. , Yuan Chun 
Published: July 2010

AbstractPurpose:To determine if better flow suppression can meaningfully improve the reproducibility of measurements associated with carotid atherosclerotic disease, particularly for lumen and wall areas.Materials and Methods:Eighteen subjects with carotid artery stenosis identified by duplex ultrasound (11 with 16%–49% stenosis; 7 with 50%–79% stenosis) underwent two carotid magnetic resonance imaging (MRI) examinations on a 3T scanner with a 4‐channel phased array coil. High‐resolution intermediate‐weighted TSE (TR/TE = 4000/8.5 msec, 0.55 mm in‐plane resolution, 2 mm slice thickness, 16 slices, 3‐minute scan time) with two different flow‐suppression techniques (multislice double inversion recovery [mDIR] and motion‐sensitized driven‐equilibrium [MSDE]) were obtained separately. For each subject, bilateral arteries were reviewed. One radiologist blinded to timepoints, flow suppression techniques, and clinical information measured the arterial lumen area, wall area, and total vessel wall area.Results:Compared to mDIR, the MSDE technique had a smaller interscan standard deviation (SD) in lumen (SD: 3.6 vs. 5.2 mm2, P = 0.02), wall area measurements (SD: 4.5 vs. 6.4 mm2, P = 0.02), and a trend towards smaller SD in total vessel area measurement (SD: 4.4 vs. 4.9 mm2, P = 0.07).Conclusion:The results from this study demonstrate that vessel wall imaging could quantify atherosclerotic plaque measurements more reliably with an improved blood suppression technique. This relationship between flow‐suppression efficiency and reproducibility of plaque measurements is important, as more reliable area measurements will be useful in clinical diagnosis and in serial MRI studies that monitor carotid atherosclerotic lesion progression and regression. J. Magn. Reson. Imaging 2010;32:452–458. © 2010 Wiley‐Liss, Inc.
The First Half‐Century of Laser Development
Authors: Hecht Jeff 
Published: July 2010

AbstractThe laser was born on May 16, 1960 at Hughes Research Laboratories in Malibu, California. Instead of enjoying the view of the Pacific from his new office window, Theodore Maiman closeted himself in a windowless lab, where he slipped a spring‐shaped photographic flashlamp over a stubby ruby rod, then put the assembly inside a reflective cylinder. Firing pulses with higher and higher voltage through the lamp, he carefully studied oscilloscope traces of the rise and fall of the ruby's red fluorescence. Once the voltage exceeded 950 volts, the lamp flashed bright enough to excite the ruby above laser threshold. The red light suddenly flashed so bright that Maiman's colorblind assistant Irnee D'Haenens saw red light for the first time [1]! The instruments recorded what Maiman had predicted would happen above laser threshold – the pulse rose and fell faster, and the range of red wavelengths narrowed. This article provides an overview of the first 50 years of laser development as well as a brief outlook what's coming next.
Nächste Generation des Laserselektivlötens
Authors: Deininger Christoph 
Published: July 2010

AbstractDas Löten von Elektronikkomponenten moderner Produkte nimmt im Produktionsalltag vieler Hersteller stetig zu. Durch eine stetige Entwicklung hin zu komplexeren Bauteilen werden dabei Selektivlötprozesse immer wichtiger. Dieser Artikel beschreibt einen neuen laserbasierten Ansatz zum Selektivlöten, der durch Kombination intelligenter Systemkomponenten eine neue Dimension des Laserlötens eröffnet.
Amelioration of an acid ultisol by agricultural by‐products
Authors: Wang N. , Xu R.‐K. , Li J.‐Y. 
Published: July 2010

AbstractUltisols are widely distributed in the subtropical regions of China as well as in the world. High acidity of Ultisols limits plant growth and reduces crop yields. Amelioration of an acid Ultisol was investigated by incorporating the residues of canola (Brassica campestris L.), wheat (Triticum aestivum L.), rice (Oryza sativa), corn (Zea mays), soybean (Glycine max), peanut (Arachis hypogaea), faba bean (Vicia faba L.) and pea (Pisum sativum) and Chinese milk vetch (Astragalus sinicus L.) shoots after incubation of the agricultural by‐products for a maximum of 75 days, soil pH was increased by each of the plant materials. The degree of amelioration of the soil acidity by the plant materials was found to depend on the ash alkalinity and N content of the materials; the legumes of higher ash alkalinities and lower N contents, such as peanut straw and faba bean straw, led to the largest increases in soil pH, while the legumes of higher N contents showed less amelioration of the acidity to a certain degree, because of the release of protons during nitrification of NH from mineralisation of organic N. The non‐leguminous materials have medium amelioration effects and increased soil pH by 0·42–0·56 units at the end of incubation. The incorporation of the plant materials also increased exchangeable base status and reduced exchangeable Al, and thus decreased the toxicity of Al in the soil. This study demonstrates that plant materials, especially crop residues, can be used as amendments for acidic soils to restore degraded land in subtropical regions. Copyright © 2010 John Wiley & Sons, Ltd.
Population structure of three woody species in four ethnic domains of the sub‐sahel of Burkina Faso
Authors: Sop T. K. , Oldeland J. , Schmiedel U. , Ouedraogo I. , Thiombiano A. 
Published: July 2010

AbstractIn developing countries many people depend on woody resources for their livelihoods. Monitoring human impact on the populations of socio‐economically important species is therefore important for the conservation of vulnerable plants.In order to assess and compare the population structure and regeneration patterns of three multipurpose species, namely Acacia seyal Del., Balanites aegyptiaca Delile and Pterocarpus lucens Lepr. in four ethnic areas of the sub‐Sahel of Burkina Faso (Samo, Gourmantché, Fulani and Mossi), we used the size‐class distribution method (SCD) (Condit et al., 1998). Diameter at breast height (Dbh) of adult individuals of each species were sampled on 1000 m2 (20 m × 50 m) plots in each ethnic domain. Recorded Dbhs were distributed among eight size‐classes of 5 cm intervals. For each species, the slope of the regression of the SCD was considered to be an indicator of the population structure. Seedlings and saplings were recorded on five nested 25 m2 plots and fell into five height classes of 0·5 m intervals.The target species had significant (p < 0·001) negative SCD slopes with an inverse J‐shape distribution in all ethnic areas; indicating stable populations with good regeneration. Kruskal–Wallis test for the SCDs of A. seyal, B. aegyptiaca and P. lucens did not differ significantly among the ethnic areas (p > 0·1). This suggests that the dynamics of each of the three species is similar across ethnic domains and the sub‐Sahel. Data from P. lucens depicted an apparent stable population structure which contrasted with our field observations, perception of local people and previous studies. Copyright © 2010 John Wiley & Sons, Ltd.
Highly tuned gas atomization for controlled preparation of coarse powder
Authors: Anderson I. E. , Byrd D. , Meyer J. 
Published: July 2010

AbstractWhile close‐coupled gas atomization has been demonstrated for highly controlled production of fine powders in many alloy systems, defense applications for Mg powder demand that such an atomization system also be capable of producing a narrow standard deviation for coarse Mg powders. To develop this capability, a series of 5 gas atomization experiments were conducted with Al, as a less hazardous surrogate for Mg, over a range of a very low atomization gas pressures. The optimum result produced an average particle diameter of about 460 μm with a standard deviation of 1.53 using Ar atomization gas, sufficiently close to the 500 μm target size. These experiments achieved the process uniformity needed for this narrow standard deviation by stabilizing melt filming with an expanded discrete jet, close‐coupled atomization nozzle and a slotted trumpet bell pour tube. Initial analysis of the size results indicated that decreased atomization gas velocity, acting within the acceleration wave model, was the key controlling variable in this low‐pressure regime. No consistent influence of gas/melt mass flow ratio was detected in the data. Experimental observation of the atomization spray images also indicated that a practical lower limit to atomization gas pressure is about 69 kPa for achieving atomization process uniformity with the method of this study.
Spray forming of stainless steel matrix composites with injection of hard particulates
Authors: Cui C. , Schulz A. , Uhlenwinkel V. , Zobel F. , Zoch H.‐W. 
Published: July 2010

AbstractTo produce new types of wear resistant and corrosion resistant materials for the manufacture of knives, hard particles (TiC and VC, size 1–10 μm) have been injected into martensitic stainless steel (X46Cr13) and austenitic stainless steel (X2CrNiMo17‐12‐2) during spray forming, respectively. To eliminate porosity in the deposits and prepare semi‐finished materials for subsequent applications, the spray‐formed billets (diameter 130 mm–160 mm after peeling) have been hot worked to bars (75 mm×25 mm or 75 mm×15 mm) and thin plates (7–8 mm thickness). The microstructures and properties of the spray‐formed and hot worked steel matrix composites have been investigated and evaluated. A porosity level less than 1% in the as‐deposited composites can be achieved under proper carbide powder feeding and spray forming conditions. The carbide particles are more homogeneously distributed in the steel matrices after hot working. The hardness of the spray‐formed composites, particularly the austenitic steel matrix composites, increases significantly with increasing carbide content. The abrasive wear resistance of the composites is also improved.Neue Arten von verschleißfesten und korrosionsbeständigen Materialien wurden erzeugt, indem beim Sprühkompaktieren Refraktärmetallcarbide (MC), speziell TiC und VC (Partikelgröße 1–10 μm), in den rostfreien martensitischen Stahl (X46Cr13) und den austenitischen Stahl (X2CrNiMo17‐12‐2) eingebracht wurden. Zur Verdichtung und Formgebung zu Halbzeugen für spätere Anwendungen als Schneidwerkzeuge wurden die sprühkompaktierten, bolzenförmigen Deposits zunächst zu Platinen (75×25 bzw. 75×15 mm2) geschmiedet und dann weiter zu 7–8 mm dünnen Blechen warmgewalzt. Gefüge und Eigenschaften der sprühkompaktierten Stahl‐Verbundwerkstoffe wurden untersucht und bewertet. Unter geeigneten Bedingungen bei der Pulverzufuhr und beim Sprühkompaktieren kann die Porosität in den Deposits unter 1% liegen. Die Karbidpartikel sind nach der Warmumformung in der Stahl‐Matrix homogener verteilt. Die Härte der sprühkompaktierten Verbundwerkstoffe, insbesondere der austenitischen Matrix‐Composites, steigt signifikant mit zunehmendem Hartstoffgehalt. Die Verschleißfestigkeit der Verbundwerkstoffe wird ebenfalls gesteigert.
Why is spray forming a rapid solidification process?
Authors: Henein H. 
Published: July 2010

AbstractSince the invention of spray forming by Prof. Singer in the early 80's, many researchers have attempted to explain the rapid solidification features of the spray deposit through mathematical modelling of the process. The break‐up of the stream into atomized drops followed by the deposition of these semi‐solid droplets into a rotating deposit have been simulated using both the energy and the momentum equations. These models, however, do not explain the fineness of structure observed in spray formed products when compared to cast structures of similar dimensions and experiencing similar cooling rates. A single fluid technique provides an ideal tool to study the effect of atomization variables on the structure evolution of a spray formed deposit. It will be shown based on Cu‐6Sn, Al‐Cu and Al‐Fe alloys that the undercooling of second and subsequent phases in the deposit accounts for the rapid solidified structure in spray forming.
Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy
Authors: Kaur K. , Pandey O. P. 
Published: July 2010

AbstractThe requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent‐divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work.