Operating room personnel (ORP) operating mobile image intensifier systems (C-arms) need training to produce high quality radiographs with a minimum of time and X-ray exposure. Our study aims at ...evaluating acceptance, usability and learning effect of the CBT system virtX that simulates C-arm based X-ray imaging in the context of surgical case scenarios.
Prospective, interventional study conducted during an ORP course with three groups: intervention group 1 (training on a PC using virtX), and 2 (virtX with a C-arm as input device), and a control group (training without virtX) - IV1, IV2 and CG. All participants finished training with the same exercise. Time needed to produce an image of sufficient quality was recorded and analyzed using One-Way-ANOVA and Dunnett post hoc test (alpha = .05). Acceptance and usability of virtX have been evaluated using a questionnaire.
CG members (n = 21) needed more time for the exercise than those of IV2 (n = 20): 133 +/- 55 vs. 101 +/- 37 sec. (p = .03). IV1 (n = 12) also performed better than CG (128 +/- 48 sec.), but this was not statistically significant. Seventy-nine participants returned a questionnaire (81% female, age 34 +/- 9 years, professional experience 8.3 +/- 7.6 years; 77% regularly used a C-arm). 83% considered virtX a useful addition to conventional C-arm training. 91% assessed virtual radiography as helpful for understanding C-arm operation.
Trainees experienced virtX as substantial enhancement of C-arm training. Training with virtX can reduce the time needed to perform an imaging task.
Cryptomonads are unicellular algae with chloroplasts surrounded by four membranes. Between the inner and the outer pairs of membranes is a narrow plasmatic compartment which contains a nucleus-like ...organelle called the nucleomorph. Using pulsed field gel electrophoresis it is shown that the nucleomorph of the cryptomonad Pyrenomonas salina contains three linear chromosomes of 195 kb, 225 kb and 240 kb all of which encode rRNAs. Thus, this vestigial nucleus has a haploid genome size of 660 kb, harboring the smallest eukaryotic genome known so far. From the cell nucleus of P. salina at least 20 chromosomes ranging from 230 kb to 3.000 kb were fractionated. Here, the rDNA was detected on a single chromosome of about 2.500 kb.
The cryptomonad Pyrenomonas salina presumably has arisen from a symbiotic event involving a flagellated phagotrophic host cell and a photosynthetic eukaryote as the symbiont. Correspondingly, in this ...unicellular alga there are four different genomes, e.g., the nuclear and the mitochondrial genomes of the host cell as well as the plastid genome and the genome contained in the vestigial nucleus of the endocytobiont (nucleomorph). To analyze the origin of one of the symbiotic partners the small subunit rRNA gene sequence of the host cell nucleus was determined, and a secondary structure model has been constructed. This sequence is compared to those of 40 other eukaryotes. A phylogenetic tree constructed using the neighborliness method revealed a close relationship between the host cell of P. salina and the chlorophytes, whereas the rhodophytes diverge more deeply in the tree.
Theatra et spectacula André, Pierre; Blin, Séverine; Bridel, Philippe ...
Études de lettres,
2011
Journal Article
Odprti dostop
Les grands édifices des jeux – théâtres, amphithéâtres et cirques – comptent parmi les monuments les plus familiers du paysage archéologique. Pourtant, en dépit d’une silhouette si caractéristique et ...d’une vocation explicite, ces grands monuments ne cessent de susciter interrogations et débats. En témoignent les travaux conduits ces dernières années par les chercheurs suisses sur les théâtres et amphithéâtres d’Avenches et d’Augst, ainsi que sur les théâtres de Lausanne et d’Alésia. La confrontation de ces recherches avec celles menées en France, au Luxembourg, en Grèce et en Libye était l’occasion d’une mise au point fructueuse concrétisée par une table ronde tenue à l’Université de Lausanne les 22 et 23 mai 2008. L’origine et le sens de ces édifices, leur histoire et leur évolution architecturale propre, les différents types d’usage qu’ils autorisaient, le rôle politique et social qu’ils jouaient, sont autant de problématiques auxquelles ce volume collectif, fort de quinze contributions variées et inédites, tente d’apporter un éclairage nouveau.
Mobile communication systems as, e.g, UMTS LTE perform rate matching and Hybrid Automatic Repeat reQuest (HARQ) to provide adequate decoding performance over a wide range of channel conditions. In ...UMTS LTE this is realized by means of a fixed rate convolutional Turbo code and a rate matching scheme based on bit puncturing and bit repetition. A promising alternative to convolutional Turbo codes with simple bit repetition are Rate-Compatible Insertion Convolutional (RCIC) Turbo codes which have proven considerable performance gains in systems without HARQ. Since modern systems conventionally employ HARQ, a novel HARQ scheme for UMTS LTE based on RCIC Turbo codes is presented in this paper. Extensive simulations have demonstrated that the conventional UMTS LTE HARQ scheme is outperformed by our novel HARQ scheme in terms of system throughput.
Background: Focal 68Ga-DOTATATE PET lesions within the myocardium of neuroendocrine tumor (NET) patients are observed in clinical practice. We determined the frequency and characteristics of lesions ...that are consistent with cardiac metastasis and assessed the lesion detection rate of conventional imaging. Methods: 629 patients who underwent 68Ga-DOTATATE PET-CT at a supraregional comprehensive cancer center on NET were included from a consecutive registry. Inclusion criteria were: (1) focal 68Ga-DOTATATE tracer uptake within the myocardium in more than two sequential PET exams, and (2) contrast-enhanced CT. To determine the diagnostic accuracy of conventional CT imaging, a case-control cohort with a ratio of 1:3 was used. PET and CT were independently analyzed by two blinded readers. Cohen's K was assessed for interreader agreement Descriptive statistics were applied for frequencies and characteristics and group comparisons were analyzed using the Fisher's exact test. Results: The prevalence of myocardial metastases related to the registry was 2.4% (15 of 629 NET patients fulfilling the inclusion criteria), for a total of 21 myocardial 68Ga-DOTATATE foci detected. Myocardial lesions were most frequently located in the left ventricle (43%) and the septum (43%). No patient demonstrated a pericardial effusion. Patients with myocardial metastases did not differ in demographics, tumor grading, disease stage or circulating tumor markers compared to the overall registry (all p > 0.05). Higher Ki67-Indices were observed (p = 0.049) for patients with myocardial metastases. Interreader agreement for PET assessment was excellent (Cohen's K = 1.0). CT reading showed a sensitivity of 19% (95% confidence interval: 6-43%) at a specificity of 100% (95% confidence interval: 90-100%). Conclusions: 68Ga-DOTATATE PET enables detection of myocardial metastatic lesions in NET patients. In contrast, standard morphologic CT imaging provides very limited sensitivity.
Background: The purpose of the study was to investigate a novel BRAF and CDK 4/6 inhibitor combination therapy in a murine model of BRAF-V600-mutant human melanoma monitored by F-18-FDG-PET/CT and ...diffusionweighted MRI (DW-MRI). Methods: Human BRAF-V600-mutant melanoma (A375) xenograft-bearing balb/c nude mice (n = 21) were imaged by 18F-FDG-PET/CT and DW-MRI before (day 0) and after (day 7) a 1-week BRAF and CDK 4/6 inhibitor combination therapy (n = 12;dabrafenib, 20 mg/kg/d;ribociclib, 100 mg/kg/d) or placebo (n = 9). Animals were scanned on a small animal PET after intravenous administration of 20 MBq F-18-FDG. Tumor glucose uptake was calculated as the tumor-to-liver-ratio (TTL). Unenhanced CT data sets were subsequently acquired for anatomic coregistration. Tumor diffusivity was assessed by DW-MRI using the apparent diffusion coefficient (ADC). Anti-tumor therapy effects were assessed by ex vivo immunohistochemistry for validation purposes (microvascular density -CD31;tumor cell proliferation -Ki-67). Results: Tumor glucose uptake was significantly suppressed under therapy (Delta TTLTherapy -1.00 +/- 0.53 vs.Delta TTLControl 0.85 +/- 1.21;p < 0.001). In addition, tumor diffusivity was significantly elevated following the BRAF and CDK 4/6 inhibitor combination therapy (Delta ADC(Therapy) 0.12 +/- 0.14 x 10(-3) mm(2)/s;Delta ADCControl -0.12 +/- 0.06 x 10(-3) mm(2)/s;p < 0.001). Immunohistochemistry revealed a significant suppression of microvascular density (CD31, 147 +/- 48 vs. 287 +/- 92;p = 0.001) and proliferation (Ki-67, 3718 +/- 998 vs. 5389 +/- 1332;p = 0.007) in the therapy compared to the control group. Conclusion: A novel BRAF and CDK 4/6 inhibitor combination therapy exhibited significant anti-angiogenic and anti-proliferative effects in experimental human melanomas, monitored by F-18-FDG-PET/CT and DW-MRI.
PDF
