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Search Results: 1 - 10 of 32540 matches for " Thomas Josef Vogl "
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Dose Efficiency in Dual Source High-Pitch Computed Tomography of the Chest  [PDF]
Boris Bodelle, Thomas Lehnert, Martin Beeres, Thomas Josef Vogl, Boris Schulz
Advances in Computed Tomography (ACT) , 2014, DOI: 10.4236/act.2014.34008

Objectives: Evaluation of radiation efficiency of dual source high-pitch (DSHP) chest CT in comparison to single source technique with special regards to individual patient anatomy. Methods: 150 consecutive patients who underwent chest CT with automated tube current modulation were evaluated retrospectively and divided into three study groups, each with an equal quantity of 50 patients (DSHP vs. single source 128 slices vs. single source 16 slices). By using a dedicated workstation, volumetric analyses of each of the scanned anatomic area were performed and correlated to the individual dose length product (DLP). The calculated result was defined as dose efficiency. Results: DLP was 203 mGycm (DSHP), vs. 269 mGycm (single source) vs. 273 mGycm (16 slice CT). The total patient volume was lowest in the dual source group with 18956.3 cm3 (vs. 22481.2 cm3 vs. 22133.8 cm3). With regards to the DLP, the calculated dose efficiency of dual source CT was better than the 128 slice CT (p = 0.045) and the 16 slice CT (p < 0.01). Conclusions: DSHP CT has considerably better dose efficiency compared to 16 slice CT. Compared to 128 slice single source technique, the high-pitch mode does not cause any dose penalty when performing chest CT.

Near-infrared single-photon spectroscopy of a whispering gallery mode resonator using energy-resolving transition edge sensors
Michael F?rtsch,Thomas Gerrits,Martin J. Stevens,Dmitry Strekalov,Gerhard Schunk,Josef U. Fürst,Ulrich Vogl,Florian Sedlmeir,Harald G. L. Schwefel,Gerd Leuchs,Sae Woo Nam,Christoph Marquardt
Physics , 2014, DOI: 10.1088/2040-8978/17/6/065501
Abstract: We demonstrate a method to perform spectroscopy of near-infrared single photons without the need of dispersive elements. This method is based on a photon energy resolving transition edge sensor and is applied for the characterization of widely wavelength tunable narrow-band single photons emitted from a crystalline whispering gallery mode resonator. We measure the emission wavelength of the generated signal and idler photons with an uncertainty of up to 2 nm.
Local Perceptions and Responses to Climate Change and Variability: The Case of Laikipia District, Kenya
Sarah Ayeri Ogalleh,Christian R. Vogl,Josef Eitzinger,Michael Hauser
Sustainability , 2012, DOI: 10.3390/su4123302
Abstract: Agricultural policies in Kenya aim to improve farmers’ livelihoods. With projected climate change, these policies are short of mechanisms that promote farmers’ adaptation. As a result, smallholders are confronted with a variety of challenges including climate change, which hinders their agricultural production. Local knowledge can be instrumental in assisting smallholders to cope with climate change and variability. In this paper, we present empirical evidence that demonstrates local knowledge, perceptions and adaptations to climate change and variability amongst smallholders of Laikipia district of Kenya. A Palmer Drought Severity Index (PDSI) calculated for one station is compared with smallholders’ perceptions. Data was collected using qualitative and quantitative methods in Umande and Muhonia sub-locations. Qualitative data included 46 transcripts from focus group discussions and key informant interviews. Quantitative data is derived from 206 interviewees. We analyzed qualitative and quantitative data using Atlas-ti and SPSS respectively. According to smallholders’ perceptions, climatic variability is increasingly changing. Local perceptions include decreasing rainfalls, increasing temperatures, increasing frosts and increasing hunger. The PDSI shows a trend towards severe droughts in the last four decades, which is in accordance with farmers’ perceptions. Smallholders use a combination of coping and adaptation strategies to respond to variability, including, among others, diversification of crop varieties, migration and sale of livestock. Significant relationships exist between drought perceptions and some adaptations such as migration and sale of livestock. Farmers have an in-depth knowledge of climatic variability, which they use to inform their coping and adaptation strategies. Knowledge of climatic perceptions and adaptations are vital entry points for decision makers and policy makers to learn how and where to enhance the adaptive capacity of smallholders in rainy and drought periods.
Different imaging techniques in the head and neck: Assets and drawbacks
Thomas J Vogl, Marc Harth , Petra Siebenhandl
World Journal of Radiology , 2010,
Abstract: In this review, the gold standard imaging techniques for the head and neck and the latest upcoming techniques are presented, by comparing computed tomography (CT), magnetic resonance imaging and positron emission tomography-CT, as well as ultrasound, depending on the examined area. The advantages and disadvantages of each examination protocol are presented. This article illustrates the connection between the imaging technique and the examined area. Therefore, the head and neck area is divided into different sections such as bony structures, nervous system, mucous membranes and squamous epithelium, glandular tissue, and lymphatic tissue and vessels. Finally, the latest techniques in the field of head and neck imaging such as multidetector CT, dual-energy CT, flash CT, magnetic resonance angiography, spectroscopy, and diffusion tensor tractography using 3 tesla magnetic resonance are discussed.
Computed Tomography Guided Percutaneous Liver Biopsy Using a Robotic Assistance Device—A Corpse Study  [PDF]
Boris Schulz, Katrin Eichler, Firas Al-Butmeh, Claudia Frellesen, Christoph Czerny, Thomas Vogl, Stephan Zangos
Open Journal of Radiology (OJRad) , 2015, DOI: 10.4236/ojrad.2015.52014
Abstract: Purpose: To investigate a robot assistance device for CT-guided percutan liver biopsy. Materials and Methods: The liver of a corpse was equipped with target dummies. Four radiologists used a 16 G needle to perform biopsy of the target region in standard free hand technique and then used a robot system which allowed planning and aligning the trajectory path. Accuracy in terms of needle tip deviation, and time efficiency and radiation exposure in terms of effective dose for the radiologists were measured. Results: For in plane procedures, there was no significant benefit in accuracy when using the robot versus standard technique (4 mm vs. 5.6 mm, p = 0.11); timely effort was worse (443 sec vs. 405 sec, p = 0.64). For angulated punctures, a needle tip of 3.7 mm was measured by using the robotic device (vs. 10.8 mm, p < 0.01); mean biopsy duration was 490 sec (vs. 900 sec, p < 0.01). Mean radiation exposures in freehand technique were 2.4 μSv (in plane procedures) and 10.8 μSv (oblique procedures); the robotic assisted procedures were performed without additional image guidance. Conclusion: The proposed robotic assistance device may be superior for angulated interventions regarding accuracy and timely effort. Furthermore, the zero radiation exposure is a significant benefit for the interventional radiologist.
Perinatal testicular torsion—An emergency with grave consequences  [PDF]
Dietrich Doll, Josef Erkel, Thomas Erhart, Christian H?nemann
Case Reports in Clinical Medicine (CRCM) , 2013, DOI: 10.4236/crcm.2013.21019

Introduction: Perinatal testicular torsion is not a frequent, but a grave finding finding. As only immediate surgical retorsion may save the viability of the testicle, time is of essence. We report the case of a newborn where delayed diagnosis led to an unnecessary loss of one testicle. Presentation of Case: The newborn was presented one day after delivery with a swollen left blue scrotal pouch. The left testicle was little tender, higher in position and enlarged. Ultrasound revealed a globular, enlarged testicle left, showing hypodense necrotic areas within. Doppler sound could not detect any perfusion of the spermatic vessels. Scrotal fluid was present bilaterally. At operation, the testicle was considered unsalvageable, and left orchiectomy and right orchidopexy were performed. Discussion: In the new-born, it is more than convenient to perfom ultrasound of both testicles at the same time, which allows to compare texture and perfusion easily. Immediate surgical exploration should be performed at any time, even if in diagnostic doubt. The very most important step though is to professionally recognise and to react to this pediatric emergency, as time is of paramount essence. Conclusion: A case of a male newborn with unilateral perinatal testicular torsion is presented, where typical clinical signs and ultrasound features can be seen. Early exploration with orchiectomy of the necrotic testicle and orchidopexy of the healthy side may save the endocrine function and fertility.

Quantitative EEG Changes in Patients with Parkinson’s Disease during Therapy with Rasagiline  [PDF]
Wilfried Dimpfel, Christian Oehlwein, Josef Anton Hoffmann, Thomas Müller
Advances in Parkinson's Disease (APD) , 2014, DOI: 10.4236/apd.2014.33005

It has been suggested that in patients with Parkinson’s disease (PD) metabolism of the MAO-B inhibitor selegiline to methamphetamine may contribute and/or exacerbate sleep problems, possibly leading to deficits of cognition. This open-label exploratory study included 30 PD patients currently being treated with selegiline (7.5 mg/day) and complaining of sleep disturbances. The aim of the study was to determine whether switching from selegiline to another MAO-B inhibitor without amphetamine-like metabolites, namely rasagiline, would improve sleep behaviour and cognitive function in PD patients. Pathologic aberrations as determined by comparison of the frequency pattern of patients to a database consisting of healthy subjects revealed an approximation of electric brain activity to normality. For verification of efficacy, a combination of questionnaires, quantitative source density EEG recording with CATEEMò and performance of two psychometric tasks (d2-test of attention and reading) during the EEG recording were done on the last day of selegiline treatment (7.5 mg/day) as well as 2 and 4 months later, during which the patients were treated with rasagiline (1 mg/day). In addition, performance of the mental tasks revealed a statistically significant (p < 0.05) increase of theta power (4.75 - 6.75 Hz) indicative of improved cognitive abilities at the end of the treatment period. At the same time evaluation of the psychometric test results indicated a statistical improvement with respect to the score of the d2-test (increase from 6.54 to 7.37; p < 0.05). Serum levels of methamphetamine were measured before and after intake of selegiline or rasagiline. They were correlated to alpha2 power, which is under dopaminergic control, within the temporal lobe. From these results it is concluded that the switch from selegiline to rasagiline not only improved sleep behaviour as reported separately but also had a positive effect on electric brain activity and on cognition in these patients.

Pro-Inflammatory S100A8 and S100A9 Proteins: Self-Assembly into Multifunctional Native and Amyloid Complexes
Thomas Vogl,Anna L. Gharibyan,Ludmilla A. Morozova-Roche
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13032893
Abstract: S100A8 and S100A9 are EF-hand Ca 2+ binding proteins belonging to the S100 family. They are abundant in cytosol of phagocytes and play critical roles in numerous cellular processes such as motility and danger signaling by interacting and modulating the activity of target proteins. S100A8 and S100A9 expression levels increased in many types of cancer, neurodegenerative disorders, inflammatory and autoimmune diseases and they are implicated in the numerous disease pathologies. The Ca 2+ and Zn 2+-binding properties of S100A8/A9 have a pivotal influence on their conformation and oligomerization state, including self-assembly into homo- and heterodimers, tetramers and larger oligomers. Here we review how the unique chemical and conformational properties of individual proteins and their structural plasticity at the quaternary level account for S100A8/A9 functional diversity. Additional functional diversification occurs via non-covalent assembly into oligomeric and fibrillar amyloid complexes discovered in the aging prostate and reproduced in vitro. This process is also regulated by Ca 2+and Zn 2+-binding and effectively competes with the formation of the native complexes. High intrinsic amyloid-forming capacity of S100A8/A9 proteins may lead to their amyloid depositions in numerous ailments characterized by their elevated expression patterns and have additional pathological significance requiring further thorough investigation.
Electric g Tensor Control and Spin Echo of a Hole-Spin Qubit in a Quantum Dot Molecule
Robert Roloff,Thomas Eissfeller,Peter Vogl,Walter P?tz
Physics , 2010, DOI: 10.1088/1367-2630/12/9/093012
Abstract: The feasibility of high-fidelity single-qubit operations of a hole spin in a quantum dot molecule by electric g tensor control is demonstrated. Apart from a constant external magnetic field the proposed scheme allows for an exclusively electric control of the hole spin. Realistic electric gate bias profiles are identified for various qubit operations using process-tomography-based optimal control. They are shown to be remarkably robust against decoherence and dissipation arising from the interaction of the hole with host-lattice nuclear spins and phonons, with a fidelity loss of $\approx$ 1 percent for gate operation times of $\approx 10$ ns. Spin-echo experiments for the hole spin are modeled to explore dephasing mechanisms and the role of pulse-timing imperfections on the gate fidelity loss is discussed.
Analysis of and function predictions for previously conserved hypothetical or putative proteins in Blochmannia floridanus
Peter Gaudermann, Ina Vogl, Evelyn Zientz, Francisco J Silva, Andres Moya, Roy Gross, Thomas Dandekar
BMC Microbiology , 2006, DOI: 10.1186/1471-2180-6-1
Abstract: Improved sequence analysis algorithms, databanks and gene and pathway context methods allowed us to reveal new information on various enzyme and pathways from the Blochmannia floridanus genome sequence [EMBL-ID BX248583]. Furthermore, these predictions are supported and linked to experimental data for instance from structural genomics projects (e.g. Bfl341, Bfl 499) or available biochemical data on proteins from other species which we show here to be related. We were able to assign a confirmed or at least a putative molecular function for 21 from 27 previously conserved hypothetical proteins. For 48 proteins of 66 with a previous putative assignment the function was further clarified. Several of these proteins occur in many proteobacteria and are found to be conserved even in the compact genome of this endosymbiont. To extend and re-test predictions and links to experimentally verified protein functions, functional clusters and interactions were assembled. These included septum initiation and cell division (Bfl165, Bfl303, Bfl248 et al.); translation; transport; the ubiquinone (Bfl547 et al.), the inositol and nitrogen pathways.Taken together, our data allow a better and more complete description of the pathway capabilities and life style of this typical endosymbiont.Genome analysis is improved and becomes more meaningful when one considers genome context, pathway context and metabolic reconstruction. A focus on the prediction of encoded proteins and establishing links to experimentally characterized protein sequences from other organisms is particularly important in organisms where there has been characterized mainly the genome sequence. Examples are obligate intracellular endosymbionts where direct experimental identification of their proteins is very challenging. As a case in point we analyze the genome sequence from the endosymbiont Blochmannia floridanus, an obligate intracellular endosymbiont of ants of the genus Camponotus. Such symbioses between insects and
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