72 research outputs found

    Comparison of real-time elastography and multiparametric MRI for prostate cancer detection: A whole-mount step-section analysis

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    OBJECTIVE. The purpose of this study was to compare prostate cancer detection rate of real-time elastography (RTE) with that of multiparametric MRI to evaluate the advantages and disadvantages of the two methods. SUBJECTS AND METHODS. Thirty-nine patients with biopsy-proven prostate cancer underwent both RTE and multiparametric MRI to localize prostate cancer before radical prostatectomy. RTE was performed to assess prostate tissue elasticity, and hard lesions were considered suspicious for prostate cancer. Multiparametric MRI included T2-weighted MRI, diffusion-weighted MRI (DWI), and contrast-enhanced MRI (CE-MRI) with an endorectal coil at 1.5 T. After radical prostatectomy, whole-mount step sections of the prostate were generated, and the prostate cancer detection rates with both modalities were analyzed for cancer lesions measuring 0.2 cm 3 or larger. RESULTS. Histopathologic examination revealed 61 cancer lesions. RTE depicted 39 of 50 cancer lesions (78.0%) in the peripheral zone and 2 of 11 (18.2%) in the transitional zone. Multiparametric MRI depicted 45 of 50 cancer lesions (90.0%) in the peripheral zone and 8 of 11 (72.7%) in the transitional zone. Significant differences between the two modalities were found for the transitional zone and anterior part in prostates with volumes greater than 40 cm3 (p \u3c 0.05). Detection rates for high-risk prostate cancer (Gleason score ≥ 4 and 3) and cancer lesions with volumes greater than 0.5 cm3 were high for both methods (93.8% and 80.5% for RTE, 87.5% and 92.7% for multiparametric MRI). Volumetric measurements of prostate cancer were more reliable with T2-weighted MRI than with RTE (Spearman rank correlation, 0.72 and 0.46). CONCLUSION. RTE and multiparametric MRI depicted high-risk prostate cancer with high sensitivity. However, multiparametric MRI seems to have advantages in tumor volume assessment and for the detection of prostate cancer in the transitional zone and anterior part within prostates larger than 40 cm3. American Roentgen Ray Society

    Different metabolic responses during incremental exercise assessed by localized 31P MRS in sprint and endurance athletes and untrained individuals

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    Until recently, assessment of muscle metabolism was only possible by invasive sampling. 31P magnetic resonance spectroscopy ( 31P MRS) offers a way to study muscle metabolism non-invasively. The aim of the present study was to use spatially-resolved 31P MRS to assess the metabolism of the quadriceps muscle in sprint-trained, endurance-trained and untrained individuals during exercise and recovery. 5 sprint-trained (STA), 5 endurance-trained (ETA) and 7 untrained individuals (UTI) completed one unlocalized 31P MRS session to measure phosphocreatine (PCr) recovery, and a second session in which spatially-resolved 31P MR spectra were obtained. PCr recovery time constant (τ) was significantly longer in STA (50±17 s) and UTI (41±9 s) than in ETA (30±4 s), (P\u3c0.05). PCr changes during exercise differed between the groups, but were uniform across the different components of the quadriceps within each group. pH during recovery was higher for the ETA than for the UTI (P\u3c0.05) and also higher than for the STA (P\u3c0.01). Muscle volume was greater in STA than in UTI (P\u3c0.05) but not different from ETA. Dynamic 31P MRS revealed considerable differences among endurance and sprint athletes and untrained people. This non-invasive method offers a way to quantify differences between individual muscles and muscle components in athletes compared to untrained individuals. 2013 Georg Thieme Verlag KG Stuttgart.New York

    Netzwerk Teilchenwelt - Jugendliche und Lehrkräfte erfahren aktuelle Forschung in der Teilchenphysik

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    Die Förderung des Interesses von Jugendlichen an physikalischen Themen ist ein zentrales Ziel außerschulischer Lernorte. Wichtige Aspekte hierbei sind die Methoden und modernen Arbeitsweisen von PhysikerInnen. Das bundesweite „Netzwerk Teilchenwelt“ ermöglicht Jugendlichen und Lehrkräften, den Forschungsprozess in der Teilchenphysik möglichst authentisch zu erleben. In dem Beitrag wird das Programm vorgestellt, das verschiedene Vertiefungsebenen von der Teilnahme am Basisprogramm bis hin zu einem Besuch des CERN und eigenen Forschungsprojekten anbietet. Die Teilchenphysik-Masterclasses im Basisprogramm bilden das Herzstück dieses Netzwerkes. Es wird ein Einblick in die speziell für die Masterclasses entwickelte Lernumgebung gegeben, die Messungen mit realen Daten des Large Hadron Collider am CERN beinhalten. Die Masterclasses werden derzeit zur interessenfördernden Wirkung auf Jugendliche in einer wissenschaftlichen Evaluation untersucht. Erste Erkenntnisse aus der Piloterprobung der Fragebögen in Bezug zu dem Veranstaltungsformat der „International Masterclasses“ werden vorgestellt

    Brake response time before and after total knee arthroplasty: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Although the numbers of total knee arthroplasty (TKA) are increasing, there is only a small number of studies investigating driving safety after TKA. The parameter 'Brake Response Time (BRT)' is one of the most important criteria for driving safety and was therefore chosen for investigation.</p> <p>The present study was conducted to test the hypotheses that patients with right- or left-sided TKA show a significant increase in BRT from pre-operative (pre-op, 1 day before surgery) to post-operative (post-op, 2 weeks post surgery), and a significant decrease in BRT from post-op to the follow-up investigation (FU, 8 weeks post surgery). Additionally, it was hypothesized that the BRT of patients after TKA is significantly higher than that of healthy controls.</p> <p>Methods</p> <p>31 of 70 consecutive patients (mean age 65.7 +/- 10.2 years) receiving TKA were tested for their BRT pre-op, post-op and at FU. BRT was assessed using a custom-made driving simulator. We used normative BRT data from 31 healthy controls for comparison.</p> <p>Results</p> <p>There were no significant increases between pre-op and post-op BRT values for patients who had undergone left- or right-sided TKA. Even the proportion of patients above a BRT threshold of 700 ms was not significantly increased postop. Controls had a BRT which was significantly better than the BRT of patients with right- or left-sided TKA at all three time points.</p> <p>Conclusion</p> <p>The present study showed a small and insignificant postoperative increase in the BRT of patients who had undergone right- or left-sided TKA. Therefore, we believe it is not justified to impair the patient's quality of social and occupational life post-surgery by imposing restrictions on driving motor vehicles beyond an interval of two weeks after surgery.</p

    QUBE-II - Quantum Key Distribution with a CubeSat

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    The digitization of our everyday lives is omnipresent. Secure data transmission is therefore of enormous importance in almost all areas of our society. The cryptographic processes for encrypting transmitted messages used today are based on algorithms relying on the limited computing power of today's computers. However, data intercepted today can be stored, decrypted and altered in the future with more powerful or even quantum computers, which are currently under development. However, the use of quantum states as carriers of information makes physically secure communication possible. The laws of quantum mechanics guarantee that data cannot be intercepted or stored unnoticedly. The security against eavesdropping is based on fundamental laws of nature and therefore cannot be overcome even by future technologies. One approach for the global distribution of quantum keys is communication via satellite. This enables a greater range than fiber-optic links, which are currently limited to a few 100 kilometers due to losses along the line. The exchange of secret keys between several ground stations via satellite thus enables global, secure communication. The QUBE-II group is working on the development of a novel miniature satellite capable of complete quantum key exchange. The platform for this is formed by low-cost miniature satellites, so-called CubeSats. New technologies for generating quantum keys on the CubeSat platform in combination with powerful optical communication systems will enable a fully functional system in a 3x2 cube form factor. Building on the predecessor project QUBE, miniaturized quantum components are being developed that can withstand the extreme temperature and radiation loads in space. These will then be integrated into a miniature satellite weighing about 10 kilograms. The research team will use the Optical Ground Station Oberpfaffenhofen near Munich as receiver station and upgrade it accordingly for reception of QUBE quantum states and implementation of the needed classical free-space optical communication links. This paper provides insight into the structure of the QUBE-II project and lays out the challenges of a successful key exchange between CubeSat and ground station. Thereby, especially the future improvements and innovations compared to the predecessor project QUBE will be discussed

    Genome evolution in the allotetraploid frog Xenopus laevis

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    To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of ???fossil??? transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.ope

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurement of jet fragmentation in Pb+Pb and pppp collisions at sNN=2.76\sqrt{{s_\mathrm{NN}}} = 2.76 TeV with the ATLAS detector at the LHC

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