In this paper, the impact of HARQ signaling errors caused by unreliable feedback on the throughput of communication systems like UMTS LTE is investigated. We derive analytical expressions for the ...calculation of the average number of transmissions per data frame as well as the system throughput based on a general feedback channel model. In combination with the residual frame error rates (FERs) after channel decoding, measured for a system with error-free feedback, a semi-analytical evaluation of the influence of unreliable feedback information on the system throughput can be carried out for any feedback channel condition. Consequently, time-consuming simulations of the respective system with unreliable feedback can be avoided. The theoretical results are verified by extensive simulations of the UMTS LTE physical layer. They are also applicable to other communication systems.
Beta-titanium alloys such as Ti-15Mo are increasingly utilized for orthopaedic implant applications because of their excellent corrosion resistance and low elastic modulus. Particularly in ...osteosynthesis, where the biomaterial stands in direct contact to soft tissue, undesirable biologic reactions may have severe consequences especially in the vulnerable state of trauma and added iatrogenic damage to the microvascular system. In a comparative study we therefore assessed in vivo nutritive perfusion and leukocytic response of striated muscle to the biomaterials Ti-15Mo, Ti-6Al-4V and Ti-6Al-7Nb, thereby drawing conclusions on their short term inflammatory potential. Utilizing the well established skinfold chamber preparation in the hamster and intravital fluorescence microscopy, we could not demonstrate any significant discrepancies between the three alloys. All metals induced an initial moderate inflammatory response in skeletal muscle microcirculation. While recuperation of animals treated with Ti-15Mo and Ti-6Al-7Nb was prompt, we documented a slightly more sluggish recovery of Ti-6Al-4V treated animals. A gross toxicity was not observed for any of the alloys. Conclusively, Ti-15Mo, Ti-6Al-4V and Ti-6Al-7Nb induce an only transient inflammatory answer of the striated muscle microvascular system. Our results indicate that on the microvascular level the tested bulk Ti-alloys do not cause enduring biologic impairment in muscle.
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-FDG-PET/CT and ...diffusion-weighted MRI (DW-MRI).
Human BRAF-V600-mutant melanoma (A375) xenograft-bearing balb/c nude mice (n = 21) were imaged by
F-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-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).
Tumor glucose uptake was significantly suppressed under therapy (∆TTL
- 1.00 ± 0.53 vs. ∆TTL
0.85 ± 1.21; p < 0.001). In addition, tumor diffusivity was significantly elevated following the BRAF and CDK 4/6 inhibitor combination therapy (∆ADC
0.12 ± 0.14 × 10
mm
/s; ∆ADC
- 0.12 ± 0.06 × 10
mm
/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.
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-FDG-PET/CT and DW-MRI.
New three-dimensional (3D) topological phases can emerge in superlattices containing constituents of known two-dimensional topologies. Here we demonstrate that stoichiometric Bi
Te
, which is a ...natural superlattice of alternating two Bi
Te
quintuple layers and one Bi bilayer, is a dual 3D topological insulator where a weak topological insulator phase and topological crystalline insulator phase appear simultaneously. By density functional theory, we find indices (0;001) and a non-zero mirror Chern number. We have synthesized Bi
Te
by molecular beam epitaxy and found evidence for its topological crystalline and weak topological character by spin- and angle-resolved photoemission spectroscopy. The dual topology opens the possibility to gap the differently protected metallic surface states on different surfaces independently by breaking the respective symmetries, for example, by magnetic field on one surface and by strain on another surface.
Mapping brain function to brain structure is a fundamental task for neuroscience. For such an endeavour, the
larva is simple enough to be tractable, yet complex enough to be interesting. It features ...about 10,000 neurons and is capable of various taxes, kineses and Pavlovian conditioning. All its neurons are currently being mapped into a light-microscopical atlas, and Gal4 strains are being generated to experimentally access neurons one at a time. In addition, an electron microscopic reconstruction of its nervous system seems within reach. Notably, this electron microscope-based connectome is being drafted for a stage 1 larva - because stage 1 larvae are much smaller than stage 3 larvae. However, most behaviour analyses have been performed for stage 3 larvae because their larger size makes them easier to handle and observe. It is therefore warranted to either redo the electron microscopic reconstruction for a stage 3 larva or to survey the behavioural faculties of stage 1 larvae. We provide the latter. In a community-based approach we called the Ol
mpiad, we probed stage 1
larvae for free locomotion, feeding, responsiveness to substrate vibration, gentle and nociceptive touch, burrowing, olfactory preference and thermotaxis, light avoidance, gustatory choice of various tastants plus odour-taste associative learning, as well as light/dark-electric shock associative learning. Quantitatively, stage 1 larvae show lower scores in most tasks, arguably because of their smaller size and lower speed. Qualitatively, however, stage 1 larvae perform strikingly similar to stage 3 larvae in almost all cases. These results bolster confidence in mapping brain structure and behaviour across developmental stages.
We propose the combination of orthogonal frequency division multiplexing (OFDM) and turbo decodulation (TDeC) - a multiple turbo process consisting of iterative demodulation and iterative ...source-channel decoding - for transmission of correlated source codec parameters over wireless frequency-selective broadband fading channels. As OFDM systems split up frequency-selective fading channels into orthogonal flat-fading channels, individual modulation signal constellations sets with different bit mapping rules can be assigned to subcarriers taking into account the iterative reception and decoding process. The superior performance of the proposed OFDM-TDeC system is demonstrated by analyzing the achieved residual bit error rate (BER) and parameter signal-to-noise ratio (SNR).
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.
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.
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