bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interleaved variable density sampling with a constrained parallel imaging reconstruction for dynamic contrast‐enhanced MR angiography
Authors: Wang Kang , Busse Reed F. , Holmes James H. , Beatty Philip J. , Brittain Jean H. , Francois Christopher J. , Reeder Scott B. , Du Jiang , Korosec Frank R. 
Published: March 2011

AbstractFor MR applications such as contrast‐enhanced MR angiography, it is desirable to achieve simultaneously high spatial and temporal resolution. The current clinical standard uses view‐sharing methods combined with parallel imaging; however, this approach still provides limited spatial and temporal resolution. To improve on the clinical standard, we present an interleaved variable density (IVD) sampling method that pseudorandomly undersamples each individual frame of a 3D Cartesian ky–kz plane combined with parallel imaging acceleration. From this dataset, time‐resolved images are reconstructed with a method that combines parallel imaging with a multiplicative constraint. Total acceleration factors on the order of 20 are achieved for contrast‐enhanced MR angiography of the lower extremities, and improvements in temporal fidelity of the depiction of the contrast bolus passage are demonstrated relative to the clinical standard. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Assessment of radiofrequency self‐heating around a metallic wire with MR T1‐based thermometry
Authors: Detti V. , Grenier D. , Perrin E. , Beuf O. 
Published: March 2011

AbstractHeat produced by a magnetic resonance (MR) imaging sequence in the vicinity of a conductive wire (pacemaker, electrodes, or catheter), is a subject of interest for the assessment of patient safety during imaging. For this purpose, the measurement of temperature rises during an MR imaging sequence using MR T1‐based thermometry provides several advantages, mainly in its ability to retrieve in situ real‐time thermal maps. Recent studies investigated the heat produced by an independent radiofrequency pulse, assessing MR imaging sequence heating using a specific MR thermometry sequence. This study focuses on self‐heating for which the radiofrequency pulses used for measuring temperature create the heat. An experimental design was set up to evaluate T1‐based thermometry self‐heating using a coupled/decoupled wire and to compare it with a reference temperature gathered by an optical fiber device. For the tested experimental set up, T1‐based thermometry is in fairly good agreement with optical fiber reference temperature. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Arterial input functions determined from MR signal magnitude and phase for quantitative dynamic contrast‐enhanced MRI in the human pelvis
Authors: Cron Greg O. , Foottit Claire , Yankeelov Thomas E. , Avruch Leonard I. , Schweitzer Mark E. , Cameron Ian 
Published: March 2011

AbstractDynamic contrast‐enhanced (DCE) MRI is often used to measure the transfer constant (Ktrans) and distribution volume (ve) in pelvic tumors. For optimal accuracy and reproducibility, one must quantify the arterial input function (AIF). Unfortunately, this is challenging due to inflow and signal saturation. A potential solution is to use MR signal phase (ϕ), which is relatively unaffected by these factors. We hypothesized that phase‐derived AIFs (AIFϕ) would provide more reproducible Ktrans and ve values than magnitude‐derived AIFs (AIF|S|). We tested this in 27 prostate dynamic contrast‐enhanced MRI studies (echo time = 2.56 ms, temporal resolution = 13.5 s), using muscle as a standard. AIFϕ peak amplitude varied much less as a function of measurement location (inferior–superior) than AIF|S| (5.6 ± 0.6 mM vs. 2.6 ± 1.5 mM), likely as a result of ϕ inflow insensitivity. However, our main hypothesis was not confirmed. The best AIF|S| provided similar reproducibility versus AIFϕ (interpatient muscle Ktrans = 0.039 ± 0.021 min−1 vs. 0.037 ± 0.025 min−1, ve = 0.090 ± 0.041 vs. 0.062 ± 0.022, respectively). Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Test‐retest reliability and reproducibility of short‐echo‐time spectroscopic imaging of human brain at 3T
Authors: Gasparovic Charles , Bedrick Edward J. , Mayer Andrew R. , Yeo Ronald A. , Chen HongJi , Damaraju Eswar , Calhoun Vince D. , Jung Rex E. 
Published: March 2011

AbstractA1H magnetic resonance spectroscopic imaging study at 3T and short echo time was conducted to evaluate both the reproducibility, as measured by the interscan coefficient of variation (CV), and test‐retest reliability, as measured by the intraclass correlation coefficient (ICC), of measurements of glutamate (Glu), combined glutamate and glutamine (Glx), myo‐inositol (mI),N‐acetylaspartate, creatine, and choline in 21 healthy subjects. The effect of partial volume correction on these measures and the relationship of reproducibility and reliability to data quality were also examined. A1H magnetic resonance spectroscopic imaging slice was prescribed above the lateral ventricles and single repeat scans were performed within 30 min to minimize physiologic variability. Interscan CVs based on all the voxels varied from 0.05 to 0.07 forN‐acetylaspartate, creatine, and choline to 0.10–0.13 for mI, Glu, and Glx. Findings on the reproducibility of gray and white matter estimates ofN‐acetylaspartate, creatine, and choline are consistent with previous studies using longer echo times, with CVs in the range of 0.02–0.04 and ICC in the range of 0.65–0.90. CVs for Glu, Glx, and mI are much lower than reported in previous studies at 1.5T, while white matter mI (CV = 0.04, ICC = 0.93) and gray matter Glx (CV = 0.04, ICC = 0.68) demonstrated both high reproducibility and test‐retest reliability. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Approximate deflection of rigidly framed earth retaining structures due to an unknown earth pressure distribution
Authors: Iskander Magued , Dimond Andrew J. , Aboumoussa Walid , Masood Farah 
Published: March 2011

SUMMARYA simple and reliable method for predicting the relationship between lateral displacement and earth pressure for rigidly framed earth retaining structures (RFERS) was developed. Closed‐form equations were derived such that if one value of displacement or pressure is known (or assumed) the other can be computed for hydrostatic, seismic, uniform, and semi‐elliptical earth pressure distributions. Additionally, the general form of the equations can be used to predict the magnitude of the lateral force even if the shape of the earth pressure is unknown, with a reasonable degree of accuracy. The expressions for deflection were derived by treating the structure as an equivalent cantilever beam and calibrating the resulting expression using the finite element method (FEM). A parametric FEM analysis, of 42 000 different RFERS configurations, was performed to calibrate the expressions, using multivariate non‐linear regression between the derived expressions and FEM. A Weibull statistical analysis was performed for each equation and determined that the equations had better than 80% probability to yield deflections that are within 25% of the value computed using FEM. Furthermore, there is a 98% certainty that each equation will yield a deflection that is within 50% of that computed using FEM. Copyright © 2011 John Wiley & Sons, Ltd.
Implementation of an algorithm for general material behavior of steel taking interaction between plasticity and transformation‐induced plasticity into account
Authors: Wolff Michael , Böhm Michael , Mahnken Rolf , Suhr Bettina 
Published: March 2011

AbstractIn this article a semi‐implicit algorithm (predictor–corrector approach) for incorporating the interaction between plasticity and transformation‐induced plasticity (TRIP) in steel is developed. Contrary to the usual elasto‐plasticity, the underlying model of material behavior of steel is far more complex. The interaction between plasticity and TRIP requires extensions of algorithms developed in Doghri (Int. J. Numer. Meth. Engng 1993; 36:3915–3932) and in Mahnken (Commun. Numer. Meth. Engng 1999; 15:745–754). A particular feature of the algorithm is that the inner iteration can be reduced to a single scalar equation. Numerical examples illustrate the algorithm's capabilities. Copyright © 2011 John Wiley & Sons, Ltd.
3D NURBS‐enhanced finite element method (NEFEM)
Authors: Sevilla Ruben , Fernández‐Méndez Sonia , Huerta Antonio 
Published: March 2011

AbstractThis paper presents the extension of the recently proposed NURBS‐enhanced finite element method (NEFEM) to 3D domains. NEFEM is able to exactly represent the geometry of the computational domain by means of its CAD boundary representation with non‐uniform rational B‐splines (NURBS) surfaces. Specific strategies for interpolation and numerical integration are presented for those elements affected by the NURBS boundary representation. For elements not intersecting the boundary, a standard finite element rationale is used, preserving the efficiency of the classical FEM. In 3D NEFEM special attention must be paid to geometric issues that are easily treated in the 2D implementation. Several numerical examples show the performance and benefits of NEFEM compared with standard isoparametric or cartesian finite elements. NEFEM is a powerful strategy to efficiently treat curved boundaries and it avoids excessive mesh refinement to capture small geometric features. Copyright © 2011 John Wiley & Sons, Ltd.
Perturbation and stability analysis of strong form collocation with reproducing kernel approximation
Authors: Hu Hsin‐Yun , Chen Jiun‐Shyan , Chi Sheng‐Wei 
Published: March 2011

AbstractSolving partial differential equations using strong form collocation with nonlocal approximation functions such as orthogonal polynomials and radial basis functions offers an exponential convergence, but with the cost of a dense and ill‐conditioned linear system. In this work, the local approximation functions based on reproducing kernel approximation are introduced for strong form collocation method, called the reproducing kernel collocation method (RKCM). We perform the perturbation and stability analysis of RKCM, and estimate the condition numbers of the discrete equation. Our stability analyses, validated with numerical tests, show that this approach yields a well‐conditioned and stable linear system similar to that in the finite element method. We also introduce an effective condition number where the properties of both matrix and right‐hand side vector of a linear system are taken into consideration in the measure of conditioning. We first derive the effective condition number of the linear systems resulting from RKCM, and show that using the effective condition number offers a tighter estimation of stability of a linear system. The mathematical analysis also suggests that the effective condition number of RKPM does not grow with model refinement. The numerical results are also presented to validate the mathematical analysis. Copyright © 2011 John Wiley & Sons, Ltd.
OLED technology: also the ultimate lighting solution?
Authors: Visser Peter 
Published: March 2011

AbstractThe interest for OLEDs (Organic Light Emitting Diodes) has grown since SONY sold out its first two shipments of the XEL‐1: an 11 inch TV with an OLED screen of only 3 mm thickness. With its superior contrast ratio, vivid colors, speed and huge viewing angle this is indeed the ultimate TV solution. But OLED technology has much more potential: it can also be applied for lighting purposes. In this article the potential and status of OLED technology for lighting applications is reviewed.
Next Generation Light Sources for Biomedical Applications
Authors: Clowes John 
Published: March 2011

AbstractLasers are increasingly important components within biological imaging and analysis systems. Applications range from flow cytometry to confocal and multi‐photon microscopy. However, many commercial imaging systems are still limited in performance by the availability of suitable laser sources‐limited in the availability of wavelengths and in the size, cost, power and reliability of conventional laser technologies. Ultrafast fibre lasers offer turnkey, compact and reliable solutions for next generation biomedical imaging systems.
Mehrdimensionale Objekterfassung mittels PMD­Sensorik
Authors: Hagebeuker Bianca 
Published: March 2011

AbstractKlassische optisch empfindliche Sensoren detektieren nur Helligkeitsinformationen und liefern damit nur ein projiziertes Abbild der Umgebung, d. h. die räumliche Information geht verloren. PMD­Sensoren dagegen registrieren inhärent das konventionelle Helligkeitsbild pixelweise mit der Tiefeninformation der betrachteten Szene. Ähnlich einem Laserradar bestimmt ein PMD­Pixel die Entfernung über das TOF­Verfahren (TOF, engl.: time­of­flight), d. h. die Echolaufzeit eines ausgesandten Lichtsignals zur Objektoberfläche und zurück wird gemessen.
EUV Sources for Lithographic Applications
Authors: Schriever Guido , Zink Peter 
Published: March 2011

AbstractSemiconductor device manufacturing is currently using excimer lasers as the light source for lithographic structuring. The wavelength of these ArF lasers is 193 nm and the high volume manufacturing of structures with 45 nm has started already. To further shrink the structure size to 32 nm and beyond, a reduction of the used wavelength is required for physical reasons. The next technology will be the extreme ultraviolet (EUV) lithography using light with 13.5 nm wavelength. Efficient optical elements like multi layer optics were developed in the last years using improvements in thin film technology on large area substrates with roughness in the sub­nanometer range. Sources for such light are plasma based sources in which the plasmas are generated either by electrical gas discharges or by pulsed laser radiation. In this paper we describe the discharge produced plasma (DPP) sources only because of their advantages concerning efficiency, simplicity, reliability and maturity.
Calcium Fluoride Crystals
Authors: Maushake Peter 
Published: March 2011

AbstractThe performance of microchips continues to double about every 18 months. The incredible progress that is being made in lithography and many other areas of technology owes a lot to calcium fluoride crystals. Low solubility and wide transmission make calcium fluoride extremely useful for a variety of different applications, including microlithography, mirror substrates for UV laser systems, windows, lenses and prisms for UV and IR applications.
Der enttarnte Terrorist
Authors: May Torsten , Meyer Hans Georg 
Published: March 2011

AbstractWieviel sicherer wären unsere Flugreisen, wenn die Kontrollbeamten wirklich alle versteckten Bedrohungen finden könnten, die potentielle Terroristen mit an Bord eines Flugzeugs schmuggeln wollen. Auf einem Terahertzbild könnte man Verdächtigen buchstäblich unter die Kleidung schauen. Doch bislang gab es noch keine Technologie, eine THz‐Videokamera zu bauen. Jenaer Forscher aus dem Institut für Photonische Technologien könnten das jetzt ändern.
Mikroskopie jenseits der Beugungsgrenze
Authors: Hell Stefan 
Published: March 2011

AbstractIn einer Festveranstaltung am 23. November 2006 in Berlin wurde der „10. Deutsche Zukunftspreis ‐ Preis des Bundespräsidenten für Technik und Innovation”︁ vergeben. Aus vier nominierten Teams wurde Stefan Hell, Direktor am Max‐Planck‐Institut für biophysikalische Chemie und Leiter der Abteilung Nano‐Biophotonik, ausgewählt und für seine bahnbrechenden Ideen zur Verbesserung der Lichtmikroskopie ausgezeichnet. Andreas Thoß sprach für Optik & Photonik mit dem Preisträger über die Hintergründe dieser Erfindung.
Industrielle Bildverarbeitung für automatisierte Produktionen
Authors: Modrich Kai‐Udo 
Published: March 2011

AbstractDie industrielle Bildverarbeitung (IBV) hat sich in vielen Branchen zu einem festen Standbein entwickelt. Sie unterstützt den Menschen bei der Triade aus „Sehen — Erkennen — Verstehen”︁, die in vielen Bereichen die Grundlage für zielgerichtetes Handeln und erfolgreiches Wirtschaften bildet. Bei hoch entwickelten Fertigungstechnologien wie auch bei hohen Personalkosten sind Produktionsanlagen nur mit einem hohen Grad an Automatisierung wirtschaftlich zu betreiben. Daher sind im industriellen Bereich effiziente Automatisierungslösungen unabdingbar.
Nanostrukturen für die Optik
Authors: Klenke Martin 
Published: March 2011

AbstractNanomaterialien sind bislang bekannt für ihre mechanischen (Lotuseffekt) oder elektrischen (Festplatte) Eigenschaften. Eine neue Idee erlaubt jetzt auch die gezielte Nutzung der optischen Eigenschaften von Nanomaterialien. Dabei geht es darum, Nanostrukturen auf ein Substrat oder ein anderes optisches Element aufzubringen und ihre wellenoptischen Eigenschaften so zu gestalten, dass sich ein definierter diffraktiver Effekt ergibt.
Chirp Managed Lasers
Authors: Fan Frank , Mahgerefteh Daniel 
Published: March 2011

AbstractHigh‐performance optical transmitters based on external modulator technologies have been used in 10 Gbps telecommunication systems for all applications that extend beyond a few kilometers. Such externally modulated transmitters require a continuous wave (CW) laser to provide the light source and a modulator to encode the digital data into the intensity of the light. Now, a new technology may eliminate the external modulators.
Precision Injection Molding
Authors: Mayer Ralf 
Published: March 2011

AbstractWhether it is a cellphone camera or a head‐up display — polymer optics is at the heart of many high tech devices and the market demand for such precision optical components is growing year by year. The main application fields are in the automotive industry, in the medical field (disposable optics), in sensor and information technology. Beside lightweight and economic advantages, polymer optics enables completely new solutions in optics. The key to all this is precision manufacturing.
Optical Design using Fresnel Lenses
Authors: Davis Arthur , Kühnlenz Frank 
Published: March 2011

AbstractThe Fresnel lens can be used in a wide variety of applications. The basic principles of the Fresnel lens are reviewed and some practical examples are described. There are definite advantages and tradeoffs that should be considered when deciding if a Fresnel lens is the appropriate component to use in a design. Some basic optimization rules are presented which may facilitate a first order design or feasibility study.
Rapid lamina propria retraction and zipper‐like constriction of the epithelium preserves the epithelial lining in human small intestine exposed to ischaemia–reperfusion
Authors: Grootjans Joep , Thuijls Geertje , Derikx Joep PM , van Dam Ronald M , Dejong Cornelis HC , Buurman Wim A 
Published: March 2011

AbstractTo ensure a sufficient barrier between a host and noxious luminal content, the intestinal epithelium must be equipped with efficient mechanisms to limit damage to the epithelial lining. Using a human model, we were able to investigate these mechanisms in the human gut exposed to ischaemia–reperfusion (IR) over the time course of 150 min. In 10 patients a part of jejunum, to be removed for surgical reasons, was selectively exposed to IR. Control tissue was collected, as well as tissue exposed to 30 min of ischaemia with 0, 30 or 120 min of reperfusion. Haematoxylin/eosin staining demonstrated the appearance of subepithelial spaces following 30 min of ischaemia, while the epithelial lining remained intact at this stage. Western blot for myosin light chain kinase (MLCK) revealed a significant increase in protein levels after ischaemia (p < 0.01), and selective staining of MLCK and phosphorylated MLC (pMLC) in lamina propria muscle fibres indicated that appearance of subepithelial spaces was a consequence of active villus contraction. Early during reperfusion, accumulation of pMLC was observed exclusively at the basal side of enterocytes that had lost contact with the collagen‐IV‐positive basement membrane. These epithelial sheets were pulled together like a zipper, even before these cells were shed. This constriction, verified by increased F‐actin and pMLC double staining, accounted for a 45% reduction in virtual wound surface (p < 0.001) at 30 min of reperfusion. In addition, these mechanisms were involved in resealing remaining small epithelial defects, resulting in a fully restored epithelial lining within 120 min of reperfusion. In conclusion, we show in a human in vivo model that the human jejunum has the ability to preserve the epithelial lining during intestinal IR by rapid lamina propria contraction and zipper‐like constriction of epithelial cells that are to be shed into the lumen. These newly described phenomena limit exposure to noxious luminal content. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Minimal residual disease detected prior to hematopoietic cell transplantation
Authors: Foster Jennifer H. , Hawkins Douglas S. , Loken Michael R. , Wells Denise A. , Thomson Blythe 
Published: March 2011

AbstractPrevious studies to evaluate minimal disease in acute lymphoblastic leukemia (ALL) after treatment have relied on the diagnostic specimen to develop patient‐specific analytical probes. The diagnostic specimen is often not available in a tertiary setting; therefore, we evaluated the use of flow cytometry (FCM) using a “difference from normal” approach to detect residual disease prior to myeloablative allogeneic hematopoietic cell transplantation (HCT). Among 116 pediatric patients with ALL who were in morphological remission at time of transplant, we found that those patients who had detectable residual disease by FCM prior to HCT experienced significantly inferior outcome. Pediatr Blood Cancer 2011;57:163–165. © 2011 Wiley‐Liss, Inc.
New computerized fetal heart rate analysis for surveillance of intrauterine growth restriction
Authors: Huhn E. A. , Lobmaier S. , Fischer T. , Schneider R. , Bauer A. , Schneider K. T. , Schmidt G. 
Published: March 2011

AbstractObjectiveDecreased fetal heart rate variability is associated with higher perinatal morbidity and mortality in intrauterine growth restriction (IUGR). This study used a new method [phase‐rectified signal averaging (PRSA)] to calculate acceleration‐ and deceleration‐related fluctuations of the fetal heart rate.MethodCardiotocograms from 74 growth‐restricted and 161 normal fetuses were included. Both groups were matched for gestational age. The transformed PRSA signal was quantified by the acceleration‐related parameter‐averaged acceleration capacity (AAC) and compared to the standard short‐term variation (STV). Mann‐Whitney test and receiver operator characteristic (ROC) curves were used for statistical analysis.ResultsFor AAC, the median values of the IUGR group and control group were 1.97 bpm [interquartile range (IQR): 1.66–2.23] and 2.49 bpm (IQR: 2.24–2.72), respectively. For STV, these values were 5.44 ms (IQR: 4.49–7.38) and 7.79 ms (IQR: 6.35–9.66), respectively. The area under the ROC curve was 81.4% for AAC and 70.5% for STV.ConclusionThe results of AAC are in both groups comparable to STV. Longitudinal studies are needed to investigate the association of AAC with the clinical outcome of the newborn. Copyright © 2011 John Wiley & Sons, Ltd.