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Search Results: 1 - 10 of 297419 matches for " Schnorr J "
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Contrast-enhanced MR imaging of atherosclerosis using citrate-coated superparamagnetic iron oxide nanoparticles: calcifying microvesicles as imaging target for plaque characterization
Wagner S,Schnorr J,Ludwig A,Stangl V
International Journal of Nanomedicine , 2013,
Abstract: Susanne Wagner,1 J rg Schnorr,1 Antje Ludwig,2 Verena Stangl,2 Monika Ebert,1 Bernd Hamm,1 Matthias Taupitz11Department of Radiology, Section of Experimental Radiology, Charité – Universit tsmedizin Berlin, Campus Charité Mitte, and Campus Benjamin Franklin, Berlin, Germany; 2Department of Cardiology, Section of Experimental Cardiology, Charité – Universit tsmedizin Berlin, Campus Charité Mitte, Berlin, GermanyObjective: To evaluate the suitability of citrate-coated very small superparamagnetic iron oxide particles (VSOP) as a contrast agent for identifying inflammation in atherosclerotic lesions using magnetic resonance imaging (MRI).Methods and results: VSOP, which have already been evaluated as a blood pool contrast agent for MR angiography in human clinical trials, were investigated in Watanabe heritable hyperlipidemic rabbits to determine to what extent their accumulation in atherosclerotic lesions is a function of macrophage density and other characteristics of progressive atherosclerotic plaques. In advanced atherosclerotic lesions, a significant MRI signal loss was found within 1 hour after intravenous administration of VSOP at the intended clinical dose of 0.05 mmol Fe/kg. Histological examinations confirmed correlations between the loss of MRI signal in the vessel wall and the presence of Prussian blue-stained iron colocalized with macrophages in the plaque cap, but surprisingly also with calcifying microvesicles at the intimomedial interface. Critical electrolyte magnesium chloride concentration in combination with Alcian blue stain indicates that highly sulfated glycosaminoglycans are a major constituent of these calcifying microvesicles, which may serve as the key molecules for binding VSOP due to their highly complexing properties.Conclusion: Calcifying microvesicles and macrophages are the targets for intravenously injected VSOP in atherosclerotic plaques, suggesting that VSOP-enhanced MRI may render clinically relevant information on the composition and inflammatory activity of progressive atherosclerotic lesions at risk of destabilization.Keywords: atherosclerosis, inflammation, magnetic resonance imaging, iron oxide nanoparticles, glycosaminoglycans, calcifying microvesicles
Iron oxide magnetic nanoparticles highlight early involvement of the choroid plexus in central nervous system inflammation
Jason?M. Millward,J?rg Schnorr,Matthias Taupitz,Susanne Wagner
ASN Neuro , 2013, DOI: 10.1042/an20120081
Abstract: Neuroinflammation during multiple sclerosis involves immune cell infiltration and disruption of the BBB (blood–brain barrier). Both processes can be visualized by MRI (magnetic resonance imaging), in multiple sclerosis patients and in the animal model EAE (experimental autoimmune encephalomyelitis). We previously showed that VSOPs (very small superparamagnetic iron oxide particles) reveal CNS (central nervous system) lesions in EAE which are not detectable by conventional contrast agents in MRI. We hypothesized that VSOP may help detect early, subtle inflammatory events that would otherwise remain imperceptible. To investigate the capacity of VSOP to reveal early events in CNS inflammation, we induced EAE in SJL mice using encephalitogenic T-cells, and administered VSOP prior to onset of clinical symptoms. In parallel, we administered VSOP to mice at peak disease, and to unmanipulated controls. We examined the distribution of VSOP in the CNS by MRI and histology. Prior to disease onset, in asymptomatic mice, VSOP accumulated in the choroid plexus and in spinal cord meninges in the absence of overt inflammation. However, VSOP was undetectable in the CNS of non-immunized control mice. At peak disease, VSOP was broadly distributed; we observed particles in perivascular inflammatory lesions with apparently preserved glia limitans. Moreover, at peak disease, VSOP was prominent in the choroid plexus and was seen in elongated endothelial structures, co-localized with phagocytes, and diffusely disseminated in the parenchyma, suggesting multiple entry mechanisms of VSOP into the CNS. Thus, using VSOP we were able to discriminate between inflammatory events occurring in established EAE and, importantly, we identified CNS alterations that appear to precede immune cell infiltration and clinical onset.
Litanei und Ostinato in Bachs Passacaglia c-moll BWV 582
Schnorr, Klemens
Anuario Musical , 2001,
Abstract: The theme of Bachs Passacaglia c-minor is based on the bass of Trio en Passacaille, a Christe-eleison-verset in the Messe du Deuziesme ton by André Raison. Bach transposes to c-minor and doubles the length of the theme, but is using the original form in four measures again for the following fugue. According to the contemporary alternatim praxis Raison's verset is the middle, central section of the nine-part Kyrie-cycle, the first part of the roman Ordinarium Missae, which is based on old litany-like acclamations and can be defined as a Litany too. May be that Bach's choosing an ostinato-form reflects the repetitive elements of a Litany and that the 33 entrances of the Passacaglia theme are related to the age of Christ. [de] Das Thema von Bachs Passacaglia c-moll beruht auf dem Bass eines Trio en Passacaille, der Christe-eleison- Versette aus der Messe du Deuziesme ton von André Raison. Bach transponiert ihn nach c-moll und verdoppelt die L nge des Themas für die Passacaglia auf acht Takte, legt aber der anschlie enden Fuge wieder die urspriingliche viertaktige Version zugrunde. Entsprechend der zeitgen ssischen Alternatimpraxis bildet Raisons Versette den mittleren, zentralen Teil des neunteiligen Kyriezyklus, der als erster Teil des Messordinariums auf frühe litaneiartige Akklamationen zurückgeht und seinerseits als Litanei gelten kann. Es scheint, als widerspiegle die Komposition eines Ostinato das repetitive Element von Litaneien und als beziehe sich das 33fache Erscheinen des Themas in der Passacaglia auf das Lebensalter Christi.
Finite volume analysis of temperature effects induced by active MRI implants with cylindrical symmetry: 1. Properly working devices
Martin HJ Busch, Wolfgang Vollmann, J?rg Schnorr, Dietrich HW Gr?nemeyer
BioMedical Engineering OnLine , 2005, DOI: 10.1186/1475-925x-4-25
Abstract: This investigation provides an overview of the supplementary power absorbed by active implants with a cylindrical geometry, corresponding to vessel implants such as stents, stent grafts or vena cava filters. The knowledge of the overall absorbed power is used in a finite volume analysis to estimate temperature maps around different implant structures inside homogeneous tissue under worst-case assumptions. The "worst-case scenario" assumes thermal heat conduction without blood perfusion inside the tissue around the implant and mostly without any cooling due to blood flow inside vessels.The additional power loss of a resonator is proportional to the volume and the quality factor, as well as the field strength of the MRI system and the specific absorption rate of the applied sequence. For properly working devices the finite volume analysis showed only tolerable heating during MRI investigations in most cases. Only resonators transforming a few hundred mW into heat may reach temperature increases over 5 K. This requires resonators with volumes of several ten cubic centimeters, short inductor circuit paths with only a few 10 cm and a quality factor above ten. Using MR sequences, for which the MRI system manufacturer declares the highest specific absorption rate of 4 W/kg, vascular implants with a realistic construction, size and quality factor do not show temperature increases over a critical value of 5 K.The results show dangerous heating for the assumed "worst-case scenario" only for constructions not acceptable for vascular implants. Realistic devices are safe with respect to temperature increases. However, this investigation discusses only properly working devices. Ruptures or partial ruptures of the wires carrying the electric current of the resonance circuits or other defects can set up a power source inside an extremely small volume. The temperature maps around such possible "hot spots" should be analyzed in an additional investigation.Metallic implants often caus
Contrast-enhanced MR imaging of atherosclerosis using citrate-coated superparamagnetic iron oxide nanoparticles: calcifying microvesicles as imaging target for plaque characterization
Wagner S, Schnorr J, Ludwig A, Stangl V, Ebert M, Hamm B, Taupitz M
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S38702
Abstract: ntrast-enhanced MR imaging of atherosclerosis using citrate-coated superparamagnetic iron oxide nanoparticles: calcifying microvesicles as imaging target for plaque characterization Original Research (660) Total Article Views Authors: Wagner S, Schnorr J, Ludwig A, Stangl V, Ebert M, Hamm B, Taupitz M Published Date February 2013 Volume 2013:8 Pages 767 - 779 DOI: http://dx.doi.org/10.2147/IJN.S38702 Received: 01 October 2012 Accepted: 02 December 2012 Published: 20 February 2013 Susanne Wagner,1 J rg Schnorr,1 Antje Ludwig,2 Verena Stangl,2 Monika Ebert,1 Bernd Hamm,1 Matthias Taupitz1 1Department of Radiology, Section of Experimental Radiology, Charité – Universit tsmedizin Berlin, Campus Charité Mitte, and Campus Benjamin Franklin, Berlin, Germany; 2Department of Cardiology, Section of Experimental Cardiology, Charité – Universit tsmedizin Berlin, Campus Charité Mitte, Berlin, Germany Objective: To evaluate the suitability of citrate-coated very small superparamagnetic iron oxide particles (VSOP) as a contrast agent for identifying inflammation in atherosclerotic lesions using magnetic resonance imaging (MRI). Methods and results: VSOP, which have already been evaluated as a blood pool contrast agent for MR angiography in human clinical trials, were investigated in Watanabe heritable hyperlipidemic rabbits to determine to what extent their accumulation in atherosclerotic lesions is a function of macrophage density and other characteristics of progressive atherosclerotic plaques. In advanced atherosclerotic lesions, a significant MRI signal loss was found within 1 hour after intravenous administration of VSOP at the intended clinical dose of 0.05 mmol Fe/kg. Histological examinations confirmed correlations between the loss of MRI signal in the vessel wall and the presence of Prussian blue-stained iron colocalized with macrophages in the plaque cap, but surprisingly also with calcifying microvesicles at the intimomedial interface. Critical electrolyte magnesium chloride concentration in combination with Alcian blue stain indicates that highly sulfated glycosaminoglycans are a major constituent of these calcifying microvesicles, which may serve as the key molecules for binding VSOP due to their highly complexing properties. Conclusion: Calcifying microvesicles and macrophages are the targets for intravenously injected VSOP in atherosclerotic plaques, suggesting that VSOP-enhanced MRI may render clinically relevant information on the composition and inflammatory activity of progressive atherosclerotic lesions at risk of destabilization.
Cardiac MR Elastography: Comparison with left ventricular pressure measurement
Thomas Elgeti, Michael Laule, Nikola Kaufels, J?rg Schnorr, Bernd Hamm, Abbas Samani, Jürgen Braun, Ingolf Sack
Journal of Cardiovascular Magnetic Resonance , 2009, DOI: 10.1186/1532-429x-11-44
Abstract: Three pigs of different cardiac physiology (weight, 25 to 53 kg; heart rate, 61 to 93 bpm; left ventricular [LV] end-diastolic volume, 35 to 70 ml) were subjected to invasive LV pressure measurement by catheter and noninvasive cardiac MRE. Cardiac MRE was performed in a short-axis view of the heart and applying a 48.3-Hz shear-wave stimulus. Relative changes in LV-shear wave amplitudes during the cardiac cycle were analyzed. Correlation coefficients between wave amplitudes and LV pressure as well as between wave amplitudes and LV diameter were determined.A relationship between MRE and LV pressure was observed in all three animals (R2 ≥ 0.76). No correlation was observed between MRE and LV diameter (R2 ≤ 0.15). Instead, shear wave amplitudes decreased 102 ± 58 ms earlier than LV diameters at systole and amplitudes increased 175 ± 40 ms before LV dilatation at diastole. Amplitude ratios between diastole and systole ranged from 2.0 to 2.8, corresponding to LV pressure differences of 60 to 73 mmHg.Externally induced shear waves provide information reflecting intraventricular pressure changes which, if substantiated in further experiments, has potential to make cardiac MRE a unique noninvasive imaging modality for measuring pressure-volume function of the heart.Today several cardiac imaging modalities are available that provide excellent information on cardiac morphology and tissue structure with high temporal resolution [1-4]. However, as these modalities cannot measure forces, insight into myocardial physiology, particularly initiation of contraction and relaxation, is limited. To obtain information on cardiac elasticity and contractility in a clinical setting, it is still necessary to perform invasive catheterization for direct measurement of pressure in the chamber of interest [5]. Such information is very important as abnormal alteration of ventricular pressure between systole and diastole can sensitively indicate a variety of diseases such as hypertrophy or dysfunc
The Perspective of Crack Users Regarding Their Social Reintegration after the End of Treatment in Therapeutic Communities  [PDF]
Analu Schnorr, Adriana R. Binsfeld Hess, Laíssa Eschiletti Prati
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.54040
Abstract:

The use of crack cocaine has been gaining prominence in the media, because even though it’s a phenomenon that emerged little more than twenty years ago, it’s already an epidemic in Brazil. The large number of crack users represents a public health problem, affecting family, professional and social relations. This study investigated the perspectives of crack users regarding their social reintegration. The sample was composed of ten addicted men between the ages of 19 and 37, admitted to therapeutic communities for a social reintegration process. Semi-structured interviews were recorded, transcribed and analyzed through Content Analysis. The main results show that studying, working with addiction and meeting the expectations of family appear to be the main objectives of this period of rehabilitation. Other concerns that were quite emphasized referred to redeeming and gaining acceptance of the family, making new friends and keeping away from old ones (partners in use). As for their professional life, most respondents cited working with recovery as a possibility. Among the reintegration strategies, community work, the quest for God and church attendance, and attending healthy environments were mentioned. Calling and/or talking with friends was cited in relation to actions to be taken in case of a break down. These results indicate that there are several aspects that surround the social reintegration of crack addicts. They also indicate different paths that can help develop new interventions to assist dependents in the recovery phase.

Gas Streaming Motions towards the Nucleus of M81
Allan Schnorr Müller,Thaisa Storchi-Bergmann,Rogemar A. Riffel,Fabricio Ferrari,J. E. Steiner,David J. Axon,Andrew Robinson
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.18116.x
Abstract: We present stellar and gaseous kinematics of the inner 120x250pc^2 of the Liner/Seyfert 1 galaxy M81, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of 10pc. The stellar velocity field shows circular rotation but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated to a nuclear bar. The stellar velocity dispersion of the bulge is 162km/s leading to a black hole mass of M_BH=5.5x10^7M_sun based on the M_BH-sigma relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of ~-100km/s on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the center if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of ~4.0x10^-3M_sun/year, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of Principal Component Analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disk within ~50pc from the nucleus and a compact outflow, approximately perpendicular to the disk. The PCA combined with the observed gas velocity field shows that the nuclear disk is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the [OI]\Halpha line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the feeding -- via the nuclear disk and observed gas inflow, and the feedback -- via the outflow, around the nucleus of M81.
IFN-γ Production to Leishmania Antigen Supplements the Leishmania Skin Test in Identifying Exposure to L. braziliensis Infection
Daniel Schnorr equal contributor,Aline C. Muniz equal contributor,Sara Passos,Luiz H. Guimaraes,Ednaldo L. Lago,Olívia Bacellar,Marshall J. Glesby,Edgar M. Carvalho
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001947
Abstract: Background Cutaneous leishmaniasis due to L. braziliensis (CL) is characterized by a positive delayed type hypersensitivity test (DTH) leishmania skin test (LST) and high IFN-γ production to soluble leishmania antigen (SLA). The LST is used for diagnosis of CL and for identification of individuals exposed to leishmania infection but without disease. The main aim of the present study was to identify markers of exposure to L. braziliensis infection. Methodolgy/Principal Findings This cohort study enrolled 308 household contacts (HC) of 76 CL index cases. HC had no active or past history of leishmaniasis. For the present cross-sectional study cytokines and chemokines were determined in supernatants of whole blood culture stimulated with SLA. Of the 308 HC, 36 (11.7%) had a positive LST but in these IFN-γ was only detected in 22 (61.1%). Moreover of the 40 HC with evidence of IFN-γ production only 22 (55%) had a positive LST. A total of 54 (17.5%) of 308 HC had specific immune response to SLA. Only a moderate agreement (Kappa = 0.52; 95% CI: 0.36–0.66) was found between LST and IFN-γ production. Moreover while enhancement of CXCL10 in cultures stimulated with SLA was observed in HC with DTH+ and IFN-γ+ and in patients with IFN-γ+ and DTH?, no enhancement of this chemokine was observed in supernatants of cells of HC with DTH+ and IFN-γ?. Conclusions/Significance This study shows that in addition of LST, the evaluation of antigen specific IFN-γ production should be performed to determine evidence of exposure to leishmania infection. Moreover it suggests that in some HC production of IFN-γ and CXCL10 are performed by cells not involved with DTH reaction.
Obscuration in AGNs: near-infrared luminosity relations and dust colors
L. Burtscher,G. Orban de Xivry,R. I. Davies,A. Janssen,D. Lutz,D. Rosario,A. Contursi,R. Genzel,J. Gracia-Carpio,M. -Y. Lin,A. Schnorr-Mueller,A. Sternberg,E. Sturm,L. Tacconi
Physics , 2015, DOI: 10.1051/0004-6361/201525817
Abstract: We combine two approaches to isolate the AGN luminosity at near-infrared wavelengths and relate the near-IR pure AGN luminosity to other tracers of the AGN. Using integral-field spectroscopic data of an archival sample of 51 local AGNs, we estimate the fraction of non-stellar light by comparing the nuclear equivalent width of the stellar 2.3 micron CO absorption feature with the intrinsic value for each galaxy. We compare this fraction to that derived from a spectral decomposition of the integrated light in the central arc second and find them to be consistent with each other. Using our estimates of the near-IR AGN light, we find a strong correlation with presumably isotropic AGN tracers. We show that a significant offset exists between type 1 and type 2 sources in the sense that type 1 sources are 7 (10) times brighter in the near-IR at log L_MIR = 42.5 (log L_X = 42.5). These offsets only becomes clear when treating infrared type 1 sources as type 1 AGNs. All AGNs have very red near-to-mid-IR dust colors. This, as well as the range of observed near-IR temperatures, can be explained with a simple model with only two free parameters: the obscuration to the hot dust and the ratio between the warm and hot dust areas. We find obscurations of A_V (hot) = 5 - 15 mag for infrared type 1 sources and A_V (hot) = 15 - 35 mag for type 2 sources. The ratio of hot dust to warm dust areas of about 1000 is nicely consistent with the ratio of radii of the respective regions as found by infrared interferometry.
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