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Objectives The healing process of tendons after surgical treatment of tendon ruptures mainly depends on the perfusion of the tendon and its surrounding tissue. Dynamic contrast-enhanced ultrasound (DCE-US) and dynamic contrast-enhanced MRI (DCE-MRI) can provide additional information about the local microperfusion. In this pilot study, the feasibility of these techniques to assess the vascularization during tendon regeneration was evaluated. Methods Between 2013 and 2015, 23 patients with surgical treatment of traumatic rupture of quadriceps, patellar, and Achilles tendons were involved. All patients received clinical follow-up examinations at 6, 12, and at least 52 weeks postoperatively. Dynamic contrast-enhanced US and DCE-MRI examinations were performed 6 and 12 weeks postoperatively. Dynamic contrast-enhanced US perfusion was quantified by the parameters peak enhancement, wash-in area under the curve, rise time, and initial area under the curve. Correlations between these parameters were examined via the Spearman rank correlation. The clinical and functional outcomes were assessed via the Lysholm Knee Score and Knee and Osteoarthritis Outcome Score at 12 and 52 weeks postoperatively. Results Fourteen patients with quadriceps (n = 8), patellar (n = 4) and Achilles (n = 2) tendon ruptures with complete follow-up were available. The microperfusion could be successful assessed. We could detect a strong correlation of DCE-US (peak enhancement) parameters with DCE-MRI (initial area under the curve) parameters after 6 and 12 weeks. Conclusions In this pilot study, DCE-US was able to visualize the microperfusion of healing tendons with a strong correlation with DCE-MRI. Our initial results are in favor of DCE-US as a potential quantitative imaging tool for evaluating the vascularization in tendon regeneration as a complementary method.

“Oxide-Based Solid-State Batteries: A Perspective on Composite Cathode Architecture”The garnet-type phase Li7La3Zr2O12 (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid-state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all-solid-state LLZO-based battery that delivers safety, durability, and pack-level performance characteristics that are unobtainable with state-of-the-art Li-ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo- and heteroionic interfaces in a pure oxide-based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO-based SSBs.

One of the major advantages of SOFCs is their high fuel flexibility. Next to natural gas and hydrogen, which are today's most common fuels for SOFC-systems and cell-/stack-testing respectively, various other fuels are applicable as well. In the literature, a number of promising results show that available fuels as propane, butane, ammonia, gasoline, diesel etc. can be applied. Here, the performance of an anode supported cell operated in specialized single cell test benches with different gaseous and liquid fuels and reformates thereof is presented. Fuels as ammonia, dissolved urea (AddBlue(TM)), methane/steam and ethanol/water mixtures can directly be fed to the cell, whereas propane and diesel require external reforming. It is shown that in case of a stable fuel supply the cell performance with such fuels is similar to that of appropriate mixtures of H-2, N-2, CO, CO2, and steam, if the impact of endothermic reforming or decomposition reactions is considered. Even though a stable fuel cell operation with such fuels is possible in a single cell test bench, it should be pointed out that an appropriate fuel processing will be mandatory on the system level.

Supraspinatus (SSP) tendon tears represent a common indication for shoulder surgery. Yet, prediction of postoperative function and tendon retear remains challenging and primarily relies on morphologic magnetic resonance imaging (MRI)-based parameters, supported by patients' demographic data like age, gender, and comorbidities. Considering continuously high retear rates, especially in patients with larger tears and negative prognostic factors, improved outcome prediction could be of high clinical value. Contrast-enhanced ultrasound (CEUS) enables an assessment of dynamic perfusion of the SSP muscle. As a potential surrogate for muscle vitality, CEUS might reflect functional properties of the SSP and support improved outcome prediction after tendon repair. Fifty patients with isolated SSP tendon tears were prospectively enrolled. Preoperatively, SSP muscle perfusion was quantified by CEUS and conventional morphologic parameters like tear size, fatty infiltration, and tendon retraction were assessed by MRI. At six months follow-up, shoulder function, tendon integrity, and muscle perfusion were reassessed. The predictive value of preoperative CEUS for postoperative shoulder function and tendon integrity was evaluated. 35 patients entered the statistical analysis. Preoperative CEUS-based assessment of SSP perfusion significantly correlated with early postoperative shoulder function (Constant, r = 0.48, p < 0.018) and tendon retear (r = 0.67, p < 0.001). CEUS-based subgroup analysis identified patients with exceptionally high, respectively low risk for tendon retear. CEUS-based assessment of the SSP seemed to predict early shoulder function and tendon retear after SSP repair and allowed to identify patient subgroups with exceptionally high or low risk for tendon retear. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 38:1150-1158, 2020.

Purpose To evaluate the utility of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T2 mapping in evaluation of type II osteochondral lesions (OCLs) of the talus and define cutoff values for identifying patients with good/poor clinical outcomes. Materials and Methods 28 patients (mean age, 42.3 years) underwent T2 mapping and dGEMRIC at least 1.5 years (mean duration, 3.5 years) after microfracture (n = 12) or conservative (n = 16) treatment for type II OCL. Clinical outcomes were considered good with an American Orthopedic Foot and Ankle Society score ≥80. The T1/T2-values and indices of repair tissue (RT; cartilage above the OCL) were compared to those of the adjacent normal cartilage (NC) by region-of-interest analysis. The ability of the two methods to discriminate RT from NC was determined by area under the receiver operating characteristics curve (AUC) analysis. The Youden index was maximized for T1/T2 measures for identifying cutoff values indicative of good/poor clinical outcomes. Results Repair tissue exhibited lower dGEMRIC values (629.83 vs. 738.51 msec) and higher T2 values (62.07 vs. 40.69 msec) than NC (P < 0.001). T2 mapping exhibited greater AUC than dGEMRIC (0.88 vs. 0.69; P = 0.0398). All T1 measures exhibited higher maximized Youden indices than the corresponding T2 measures. The highest maximized Youden index for T1difference was observed at a cutoff value of 84 msec (sensitivity, 78%; specificity, 83%). Conclusion While T2 mapping is superior to dGEMRIC in discriminating RT, the latter better identifies good/poor clinical outcomes in patients with type II talar OCL. Level of Evidence: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1601–1610.

Purpose To assess the feasibility of gadoteric acid for delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and to compare the dGEMRIC values obtained using gadoteric acid with those obtained by an equimolar dose of Gd-DTPA. Materials and Methods At 3T, dGEMRIC of the wrist was performed twice using a T1-weighted 3D-volumetric interpolated breath-hold examination sequence in 16 healthy volunteers (10 women; mean age 26.0 years) using gadoteric acid first and Gd-DTPA 3 weeks later. In addition, 24 patients with knee pain were examined using gadoteric acid (n = 12; seven women; mean age 45.8 years) or Gd-DTPA (n = 12; four women; mean age 47.1 years). T1 values, the relative decrease in T1, and the delta R1 were compared using t-tests. Interobserver agreement was assessed using the intraclass correlation (ICC) between two independent readers. Results At the wrist, there was no significant difference in delta R1 values (0.34 ± 0.10/s, 95% confidence interval [0.30;0.38]/s for gadoteric acid and 0.32 ± 0.09 [0.29;0.35]/s for Gd-DTPA, P = 0.24) or the relative decrease in T1 (0.25 ± 0.06 [0.29;0.35] msec for gadoteric acid and 0.24 ± 0.05 [0.22;0.27] msec for Gd-DTPA, P = 0.35). High observer agreement was found at precontrast (ICC = 0.87, P < 0.001) and postcontrast (ICC = 0.89, P < 0.001). Similarly, at the knee, there was no significant difference in delta R1 (0.39 ± 0.18 [0.32;0.47]/s for gadoteric acid and 0.41 ± 0.09 [0.38;0.45]/s for Gd-DTPA, P = 0.59) or the relative decrease in T1 (0.30 ± 0.10 [0.26;0.34] msec for gadoteric acid and 0.33 ± 0.05 [0.30;0.35] msec for Gd-DTPA, P = 0.28). High ICCs of 0.96 (P < 0.01) were noted both at precontrast and postcontrast. Conclusion dGEMRIC using gadoteric acid is feasible and yields comparable values when compared with Gd-DTPA. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1433–1440.

Porous electrode models are essential for inexpensively predicting the performance and lifetime of lithium‐ion batteries. Physics‐based models range from microscopic 3D models, which spatially resolve the microstructural characteristics of all phases in porous electrodes, to reduced and computationally effective models, which do not resolve the microstructure. The homogenized Newman model, also known as the pseudo‐2D (P2D) model, is well established and widely used. However, the necessary simplification shows its weaknesses, especially for high charge and discharge rates, and these lead to significant differences in comparison with the microscopic 3D model. Herein, the validity of the homogenized Newman model is investigated with respect to variations of the microstructural characteristics of a porous cathode. The effects of 1) a homogenized conductive additive; 2) non‐spherical particle geometries; and 3) overlapping particles on charge/discharge curves are analyzed. The result is a better understanding of the validity limits of P2D models. These new insights about the individual influences of the simplifications will be used to improve the homogenized model. The simulation of complex cathode structures, where several homogenization assumptions are violated, shows that the improved homogenized model reaches a very high accuracy, and, thus, overcomes the existing limitations of the P2D model approach.

PURPOSE To evaluate the volume and changes of human brown adipose tissue (BAT) in vivo following exposure to cold using magnetic resonance imaging (MRI). MATERIALS AND METHODS The clavicular region of 10 healthy volunteers was examined with a 3T MRI system. One volunteer participated twice. A cooling vest that was circulated with temperature-controlled water was used to expose each volunteer to a cold environment. Three different water temperature phases were employed: baseline (23°C, 20 min), cooling (12°C, 90 min), and a final warming phase (37°C, 30 min). Temperatures of the water in the circuit, of the body, and at the back skin of the volunteers were monitored with fiberoptic temperature probes. Applying the 2-point DIXON pulse sequence every 5 minutes, fat fraction (FF) maps were determined and evaluated over time to distinguish between brown and white adipose tissue. RESULTS Temperature measurements showed a decrease of 3.8 ± 1.0°C of the back skin temperature, while the body temperature stayed constant at 37.2 ± 0.9°C. Focusing on the two interscapular BAT depots, a mean FF decrease of -2.9 ± 2.0%/h (P < 0.001) was detected during cold stimulation in a mean absolute volume of 1.31 ± 1.43 ml. Also, a correlation of FF decrease to back skin temperature decrease was observed in all volunteers (correlation coefficients: |r| = [0.51; 0.99]). CONCLUSION We found that FF decreases in BAT begin immediately with mild cooling of the body and continue during long-time cooling. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:369-380.

Purpose To assess the feasibility of delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) and T2 mapping for biochemical imaging of the wrist at 3T. Materials and Methods Seventeen patients with wrist pain (mean age, 41.4 ± 13.1 years) including a subgroup with chondromalacia (n = 11) and 15 healthy volunteers (26.0 ± 2.2 years) underwent dGEMRIC and T2 mapping at 3T. For dGEMRIC, the optimum time window after contrast-injection (gadopentetate dimeglumine) was defined as the plateau of the T1 curve of repeated measurements 15–90 minutes postinjection and assessed in all volunteers. Reference values of healthy-appearing cartilage from all individuals and values in areas of chondromalacia were assessed using region-of-interest analyses. Receiver-operating-characteristic analyses were applied to assess discriminatory ability between damaged and normal cartilage. Results The optimum time window was 45–90 minutes, and the 60-minute timepoint was subsequently used. In chondromalacia, dGEMRIC values were lower (551 ± 84 msec, P < 0.001), and T2 values higher (63.9 ± 17.7, P = 0.001) compared to healthy-appearing cartilage of the same patient. Areas under the curve did not significantly differ between dGEMRIC (0.91) and T2 mapping (0.99; P = 0.17). In healthy-appearing cartilage of volunteers and patients, mean dGEMRIC values were 731.3 ± 47.1 msec and 674.6 ± 72.1 msec (P = 0.01), and mean T2 values were 36.5 ± 5 msec and 41.1 ± 3.2 msec (P = 0.009), respectively. Conclusion At 3T, dGEMRIC and T2 mapping are feasible for biochemical cartilage imaging of the wrist. Both techniques allow separation and biochemical assessment of thin opposing cartilage surfaces and can distinguish between healthy and damaged cartilage. Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:381–389.

In gewissen Anwendungsbereichen haben Glasfaserbewehrungen gegenueber Stahlbewehrungen Vorteile. Der Beitrag nennt Bereiche, in denen das der Fall ist, zeigt die Unterschiede des Materialverhaltens zwischen beiden Materialien auf und stellt wichtige Grundlagen zur Bemessung mit Gladfaserkunststoff (GFK) vor. Darueber hinaus enthaelt der Beitrag einige praktische Anwendungsbeispiele. Vorteile bietet die seit etwa 20 Jahren bekannte Glasfaserbewehrung bei hoher Korrosionsgefaehrdung in korrosiver Umgebung, bei elektrisch durch Streustrom induzierter Korrosion, wenn geringe thermische Leitfaehigkeit oder Magnetfeldwirkung gefragt ist oder wenn die Bewehrung leicht zerspanbar sein muss. GFK zaehlt zu den aus zwei Grundmaterialien bestehenden Faserverbundwerkstoffen (FVK), die aus den Fasern fuer die Lastaufnahme und einer Harzmatrix fuer den inneren Verbund bestehen. Zur Beurteilung der Tragfaehigkeit und Dauerhaftigkeit von GFK sind vom Hersteller produktspezifisch abgestimmte Materialpruefungen durchzufuehren. Dazu gehoeren unter anderem Zugversuche, Langzeitzugversuche und Verbundversuche. Die grosse Zahl der auf dem Markt erhaeltlichen GFK-Produkte unterscheidet sich hinsichtlich ihrer Eigenschaften und der Qualitaetsstandards erheblich. Ein einheitliches Regelwerk fuer die Bemessung und Anwendung, zum Beispiel eine europaeisch harmonisierte Norm, ist nicht vorhanden. Fuer die Anwendung in Deutschland ist die Verwendung von Bewehrung aus GFK an eine allgemeine bauaufsichtliche Zulassung (abZ) oder eine Zustimmung im Einzelfall gebunden. Derzeit gibt es auf dem Markt nur eine Glasfaserbewehrung mit einer durch das DIBt erteilten abZ. Die aufgefuehrten Beispiele zeigen die Bandbreite der Anwendung von Faserverbundkunststoff-Bewehrung (FVB), deren Hauptanwendung bisher bei Bauwerken der Verkehrsinfrastruktur und der Elektrizitaetsversorgung liegt, darunter folgende Beispiele: Stahlbetonbauteile des Masse-Feder-Systems des Gleisdreiecks Nikolaus-Duerkopp-Strasse in Bielefeld zur Reduzierung der Emission von Koerperschall in die Umgebung; Erneuerung der Brueckenkappen der Talbruecke Trockau; 1,5 Meter dicke Stahlbetonbodenplatte einer Versuchshalle des Max-Planck-Instituts fuer Eisenforschung in Duesseldorf sowie Waende der Startbaugrube und der Vereisungsschaechte beim Eisenbahntunnel Rastatt, die von einer Tunnelvortriebsmaschine durchfahren werden. GFK hat in diesem Fall den Vorteil, dass gegenueber Stahl Schaeden an den Schneidraedern vermieden werden, da GFK zerspanbar ist. ABSTRACT IN ENGLISH: In cases where reinforcement with special requirements is needed, glass fibre reinforced polymer bars have successfully been used since more than 20 years. The first approval by the German Institute of Construction Techniques (DIBt) has been issued in 2008 giving way for broad application of this technology. This article focuses on differences in the material behaviour of mild steel and glass fibre rebar and offers basic knowledge for the design of glass fibre rebar. Additional information on comparison of different materials as well as for single use permissions (ZiE) is given. This knowledge combined with a glance on the future regulations on glass fibre rebar in the next EC2 shall enable structural engineers to perform safe calculations and a proper application of glass fibre rebar. Examples of carried out projects give an overview of the broad field of applications. (A)

The aim of our study was to assess in which way different infiltration patterns of monoclonal plasma cell diseases in whole-body (wb) magnetic resonance imaging (MRI) are associated with clinical stages, plasma cell content in bone marrow samples and established serum markers of disease activity. Institutional review board approval was obtained. We performed wb-MRI in 547 consecutive, unselected and untreated patients with monoclonal gammopathy of undetermined significance (MGUS, n = 138), smoldering myeloma (SMM, n = 157) and multiple myeloma (MM, n = 252) on two 1.5 T MRI-scanners with body array coils. The studies were evaluated in consensus by two experienced radiologists blinded to the diagnosis. We observed focal lesions in 23.9% (MGUS), 34.4% (SMM) and 81.3% (MM), respectively. A diffuse infiltration pattern was detected in 38.4%, 45.9% and 71%, respectively. The differences between all infiltration patterns were significant (p

Employing a mechanically robust metal support as the structural element in SOFC has been the objective of various development efforts. The EU-sponsored project “METSOFC”, completed at the end of 2011, resulted in a number of advancements towards implementing this strategy. These include robust metal supported cells (MSCs) having low ASR at low temperature, incorporation into small stacks of powers approaching ½kW, and stack tolerance to various operation cycles. DTU Energy Conversion's (formerly Risø DTU) research into planar MSCs has produced an advanced cell design with high performance. The novel approach has yielded roboust, defect-free cells fabricated by a unique and well-tailored co-sintering process. At low operation temperatures (650°C), these cells have shown remarkable ASRs: 0.35 Ωcm2 in cell tests (16 cm2 active area) and under 0.3 Ωcm2 in button cells (0.5 cm2 active area). Further success was attained with even larger cell areas of 12 cm squares, which facilitated integration into stacks at Topsoe Fuel Cell. Development of MSC stacks showed that the MSCs could achieve similar or better performance, compared to SoA anode supported ceramic cells. The best stacked MSCs had power densities approaching 275 mW/cm2 (at 680°C and 0.8V). Furthermore, extended testing at AVL determined extra stack performance and reliability characteristics, including behavior towards sulfur and simulated diesel reformate, and tolerance to thermal cycles and load cycles. These and other key outcomes of the METSOFC consortium are covered, along with associated work supported by the Danish National Advanced Technology Foundation.

The impact of sulfur-poisoning on reforming chemistry and electrochemistry of anode-supported solid oxide fuel cells is analyzed via electrochemical impedance spectroscopy. Different types of anode supported cells are operated in hydrogen/steam – as well as simulated reformate – (H2 + H2O + CO + CO2 + N2) fuels containing 0.1–15 ppm of H2S. A detailed analysis of impedance spectra by the distribution of relaxation times (DRT) and a subsequent complex nonlinear least squares (CLNS) fit separates the impedance changes taking place at the anode and the cathode. Two main features were detected in the DRT, a decreased reaction rate of the electrochemical hydrogen oxidation and a deactivation of the catalytic conversion of CO via the water-gas shift reaction. During the first exposure of the cell to a H2S-containing fuel, an enhanced degradation is observed. The degradation rate increases several hours after H2S was added to the fuel and decreases after the poisoning is completed. The polarization resistance increased by a factor of 2–10, depending on H2S-content, fuel composition and cell type. Comparing the temporal characteristics of the polarization resistance of two different anode supported cells, it could be shown that the accumulated H2S-amount divided by the Ni-surface area inside the anode substrate and anode functional layer determine the onset of the degradation.

A detailed electrochemical impedance study with the help of the distribution of relaxation times (DRT) method and a subsequent CNLS-fit enabled us to quantitatively analyze the different loss contributions in the cell: the ohmic resistance and the polarization processes related to the gas diffusion in the metal support, the electrochemical fuel oxidation at the anode and the oxygen reduction in the mixed ionic electronic conducting cathode. An additional process with a rather high relaxation frequency was attributed to the formation of insulating interlayers at the cathode/electrolyte-interface. Based on these results, selective measures to improve performance and stability, such as (i) PVD-deposited CGO buffer layer preventing solid state reaction between cathode and the zirconia-based electrolyte, (ii) LSC-CGO based in-situ sintered cathodes and (iii) reduced corrosion of the metal support, were adopted and validated.

In this work we investigate the effect of Cr-poisoning at OCV-condition by means of electrochemical impedance spectroscopy (EIS). The anode-supported cell (ASC) is operated in Cr-free environment for the first 70 h of the cell test at 800 °C supplying air to the cathode and a varying mixture of H2O/H2 to the anode. The performance of the cell is determined by current-voltage (CV) measurement after the start up. After an operating time of 70 h in the absence of chromium species a Cr-source was switched on by passing the oxidant (air) through a Crofer22APU powder bed. In order to determine the degradation caused by Cr-poisoning electrical impedance spectra are collected at every 29 h of operating time. After further 275 h at OCV-condition in the presence of Cr-source another CV-curve is measured. A detailed analysis of the measured impedance spectra by the distribution of relaxation times (DRT) enables a separation of the cathode polarization resistance. During the Cr-free operation the cathode polarization shows a constant value. After the Cr-source is switched on a strong increase of the cathode polarization resistance is observed. This unique result shows clearly that Cr-poisoning of an LSM/8YSZ-cathode already takes place at OCV-condition.

We propose a Bayesian smoothness prior in the spectral fitting of MRS images which can be used in addition to commonly employed prior knowledge. By combining a frequency-domain model for the free induction decay with a Gaussian Markov random field prior, a new optimization objective is derived that encourages smooth parameter maps. Using a particular parameterization of the prior, smooth damping, frequency and phase maps can be obtained whilst preserving sharp spatial features in the amplitude map. A Monte Carlo study based on two sets of simulated data demonstrates that the variance of the estimated parameter maps can be reduced considerably, even below the Cramer-Rao lower bound, when using spatial prior knowledge. Long-TE 1H MRSI at 1.5 T of a patient with a brain tumor shows that the use of the spatial prior resolves the overlapping peaks of choline and creatine when a single voxel method fails to do so. Improved and detailed metabolic maps can be derived from high-spatial-resolution, short-TE 1H MRSI at 3 T. Finally, the evaluation of four series of long-TE brain MRSI data with various signal-to-noise ratios shows the general benefit of the proposed approach.

The present study proposes a catheter system with an expandable coil etched on a polyimide foil. The catheter system combines the advantages of a small insertion diameter when the coil is rolled up in a protective carrier sheath with an increased signal-to-noise ratio (SNR) and penetration depth when the coil is pushed out. After imaging, the coil can be retracted into the sheath and folded back into the initial rolled-up configuration due to the tapered geometry of the carrier foil. The catheter system was tested on two healthy anesthetized pigs, including tracking and high-resolution intravascular imaging. To reduce artifacts in high-resolution images induced by catheter motion in the pulsatile blood flow, a motion-gating method was implemented that combines a flow-compensated two-dimensional fast low angle shot (FLASH) imaging sequence with the acquisition of projection data for retrospective gating. Using the projection data for motion detection, image SNR was increased by up to 500% over uncorrected images, and anatomic structures of 150 μm size could be differentiated in the aorta. Magn Reson Med, 2010. © 2009 Wiley-Liss, Inc.

A density-adapted three-dimensional radial projection reconstruction pulse sequence is presented which provides a more efficient k-space sampling than conventional three-dimensional projection reconstruction sequences. The gradients of the density-adapted three-dimensional radial projection reconstruction pulse sequence are designed such that the averaged sampling density in each spherical shell of k-space is constant. Due to hardware restrictions, an inner sphere of k-space is sampled without density adaption. This approach benefits from both the straightforward handling of conventional three-dimensional projection reconstruction sequence trajectories and an enhanced signal-to-noise ratio (SNR) efficiency akin to the commonly used three-dimensional twisted projection imaging trajectories. Benefits for low SNR applications, when compared to conventional three-dimensional projection reconstruction sequences, are demonstrated with the example of sodium imaging. In simulations of the point-spread function, the SNR of small objects is increased by a factor 1.66 for the density-adapted three-dimensional radial projection reconstruction pulse sequence sequence. Using analytical and experimental phantoms, it is shown that the density-adapted three-dimensional radial projection reconstruction pulse sequence allows higher resolutions and is more robust in the presence of field inhomogeneities. High-quality in vivo images of the healthy human leg muscle and the healthy human brain are acquired. For equivalent scan times, the SNR is up to a factor of 1.8 higher and anatomic details are better resolved using density-adapted three-dimensional radial projection reconstruction pulse sequence.

The transport properties of oxygen-ion conducting yttria-stabilized zirconia (YSZ)—featuring mean grain sizes from a few nm up to the μm regime—were studied with regard to grain-size effects. Chemically homogeneous, 8.3 mol% YSZ thin films (thickness approximately 400 nm) were processed on single-crystal sapphire substrates by a sol–gel method. The mean grain size d of the thin films was systematically adjusted to 5 nm≤d≤782 nm by (i) a rapid thermal annealing step for conversion into the oxide phase and (ii) a consecutive calcination step at 650°C≤Tcal (24 h) ≤1400°C for grain growth. The quality of the thin films was examined with respect to chemical homogeneity, crystal structure, grain-size, and grain-boundary properties. Total and specific conductivities of the thin films were characterized by means of electrical impedance spectroscopy at 200°≤T≤400°C in ambient air, where a complex nonlinear least-squares approximation was applied to determine the bulk conductivity and the grain-boundary conductivity. Despite grain boundaries being free of second phases, oxygen transport was observed to be impeded by the grain boundaries as the specific grain-boundary conductivity was determined to be two orders of magnitude below the bulk conductivity for thin films with d>36 nm. The transport properties of nanoscaled YSZ thin films (5 nm≤d≤36 nm) were modeled by application of the brick-layer model indicating the absence of beneficial grain-size effects at the nanoscale.

Dermato- or polymyositis must be diagnosed or ruled out early because early immunosuppressive therapy prevents irreversible muscle degeneration. Acute poly- and dermatomyositis are accompanied by normal or increased size, low echogenicity, and elevated perfusion of affected muscles, whereas in chronic poly- and dermatomyositis, the size and perfusion of affected muscles are reduced and echogenicity is increased. Although magnetic resonance imaging is more sensitive in detecting edema-like muscular changes and thereby acute myositis, contrast-enhanced ultrasound with its capability of measuring perfusion has become a useful diagnostic tool in diagnosing acute inflammation in poly- and dermatomyositis.

Besides the diagnostic evaluation of a spectrum, the assessment of its quality and a check for plausibility of its information remains a highly interactive and thus time-consuming process in MR spectroscopic imaging (MRSI) data analysis. In the automation of this quality control, a score is proposed that is obtained by training a machine learning classifier on a representative set of spectra that have previously been classified by experts into evaluable data and nonevaluable data. In the first quantitative evaluation of different quality measures on a test set of 45,312 long echo time spectra in the diagnosis of brain tumor, the proposed pattern recognition (using the random forest classifier) separated high- and low-quality spectra comparable to the human operator (area-under-the-curve of the receiver-operator-characteristic, AUC >0.993), and performed better than decision rules based on the signal-to-noise-ratio (AUC

Based on system tests, a model-aided system analysis tool is developed to model different types of fuel cell systems. In the experimental modeling approach, a model system which is general and flexible is parameterized on the basis of data measured from a system. The aim of this model is to obtain information concerning the efficiency of the system and its individual system components, to reveal problems during operation and to analyze the potential for optimization. A first evaluation of the procedure is performed on a 2 kWel and 4 kWthermal Polymer Electrolyte Membrane fuel cell (PEMFC) Combined Heat and Power (CHP) prototype system, installed at the Institut fur Werkstoffe der Elektrotechnik (IWE), Universitat Karlsruhe (TH). The system, which was developed at the Zentrum fur Sonnenenergie- und Wasserstoff-Forschung ZSW, Ulm (FC stack) and the Fraunhofer-Institut fur Solare Energiesysteme ISE, Freiburg (natural gas reformer) is operated and tested in close cooperation with the Stadtwerke Karlsruhe. The CHP system including the measurement equipment, as well as the modeling and simulation approach based on system tests are presented.

The internal reforming of methane on Ni/CGO and Ni/YSZ anodes was investigated with single cells operated at steam to carbon ratios from 0 to 3 and at temperatures of 800 °C and 950 °C. The incorporation of gas extraction ports allowed the measurement of the local gas composition in the anode gas compartment by gas chromatography. The methane conversion is presented as a function of feed gas composition, temperature, gas flow velocity, and electrical load. The impact of the anode material on the reforming reaction and on cell performance is shown. Methane conversion along the Ni/CGO anode was calculated with a one-dimensional model; the required kinetic parameters were obtained by data fitting.

(23)Na MRI has the potential to noninvasively detect sodium (Na) content changes in vivo. The goal of this study was to implement (23)Na MRI in a clinical setting for neurooncological and muscular imaging. Due to the biexponential T(2) decay of the tissue Na signal with a short component, which ranges between 0.5-8 ms, the measurement of total Na content requires imaging techniques with echo times (TEs) below 0.5 ms. A 3D radial pulse sequence with a TE of 0.2 ms at a spatial resolution of 4 x 4 x 4 mm(3) was developed that allows the acquisition and presentation of Na images on the scanner. This sequence was evaluated in patients with low- and high-grade gliomas, and higher (23)Na MR signals corresponding to an increased Na content were found in the tumor regions. The contrast-to-noise ratio (CNR) between tumor and white matter increased from 0.8 +/- 0.2 to 1.3 +/- 0.3 with tumor grade. In patients with an identified muscular (23)Na channelopathy (Paramyotonia congenita (PC)), induced muscle weakness led to a signal increase of approximately 18% in the (23)Na MR images, which was attributed to intracellular Na(+) accumulation in this region.

OBJECTIVE The purpose of this study was to develop a clinically applicable examination method to assess perfusion of the skeletal muscle using contrast-enhanced ultrasonography (CEUS) analyzing replenishment kinetics of microbubbles. METHODS Power Doppler sonography (7 MHz) after intravenous bolus injection of 10 mL of a microbubble contrast agent was used to repeatedly examine the perfusion of the right biceps muscle at rest and after defined exercise in 10 healthy volunteers. Parameters of perfusion, such as local blood volume, blood flow velocity, and perfusion, were calculated by a modified analysis of replenishment kinetics. For validation, CEUS was correlated with venous occlusion plethysmography (VOP) examining the right forearm flexor muscles at rest and after defined exercise. RESULTS The CEUS examination was easily feasible and was able to depict the physiologic large variability of the right biceps muscle perfusion at rest (mean +/- SD, 3.0 +/- 2.3 [approximately mL/s x 100 mg]) compared with the results after exercise (22.9 +/- 11.0 [approximately mL/s x 100 mg]). The perfusion calculated with VOP significantly correlated with the CEUS parameters perfusion (r = 0.81; P < .001) and blood volume (r = 0.82; P < .001). The calculated mean blood flow velocity in the right forearm flexor muscles raised from 0.41 +/- 0.24 mm/s at rest to 0.64 +/- 0.39 mm/s after exercise, showing a significant correlation with the CEUS perfusion (r = 0.72; P < .001). CONCLUSIONS Muscle perfusion can be easily and quantitatively assessed with CEUS. Compared with VOP, CEUS allows for a separate analysis of different muscle groups, unaffected by skin perfusion. Its application may be of particular interest in the diagnosis and monitoring of pathologic microvascularization in myositis or diabetic obstructive disease.