An Approach to Calculate and Visualize Intraoperative Scattered Radiation Exposure

During the intraoperative radiograph generation process with mobile image intensifier systems (C-arm) most of the radiation exposure for patient, surgeon and operation room personal is caused by scattered radiation. The intensity and propagation of scattered radiation depend on different parameters, e.g. the intensity of the primary radiation, and the positioning of the mobile image intensifier. Exposure through scattered radiation can be minimized when all these parameters are adjusted correctly. Because radiation is potentially dangerous and could not be perceived by any human sense the current education on correct adjustment of a C-arm is designed very theoretical. This paper presents an approach of scattered radiation calculation and visualization embedded in a computer based training system for mobile image intensifier systems called virtX. With the help of this extension the virtX training system should enrich the current radiation protection training with visual and practical training aspects

Electronic and Thermoelectric Properties of RuIn_{3-x}A_{x} (A = Sn, Zn)

Recently, we reported [M. Wagner et al., J. Mater. Res. 26, 1886 (2011)] transport measurements on the semiconducting intermetallic system RuIn3 and its substitution derivatives RuIn_{3-x}A_{x} (A = Sn, Zn). Higher values of the thermoelectric figure of merit (zT = 0.45) compared to the parent compound were achieved by chemical substitution. Here, using density functional theory based calculations, we report on the microscopic picture behind the measured phenomenon. We show in detail that the electronic structure of the substitution variants of the intermetallic system RuIn_{3-x}A_{x} (A = Sn, Zn) changes in a rigid-band like fashion. This behavior makes possible the fine tuning of the substitution concentration to take advantage of the sharp peak-like features in the density of states of the semiconducting parent compound. Trends in the transport properties calculated using the semi-classical Boltzmann transport equations within the constant scattering time approximation are in good agreement with the former experimental results for RuIn_{3-x}Sn_{x}. Based on the calculated thermopower for the p-doped systems, we reinvestigated the Zn-substituted derivative and obtained ZnO-free RuIn_{3-x}Zn_{x}. The new experimental results are consistent with the calculated trend in thermopower and yield large zT value of 0.8.Comment: PRB Accepted, 11 pages, 10 figure

Opioid-Induced Nausea Involves a Vestibular Problem Preventable by Head-Rest

Background and Aims Opioids are indispensable for pain treatment but may cause serious nausea and vomiting. The mechanism leading to these complications is not clear. We investigated whether an opioid effect on the vestibular system resulting in corrupt head motion sensation is causative and, consequently, whether head-rest prevents nausea. Methods Thirty-six healthy men (26.6 +/- 4.3 years) received an opioid remifentanil infusion (45 min, 0.15 mu g/kg/min). Outcome measures were the vestibulo-ocular reflex (VOR) gain determined by video-head-impulse-testing, and nausea. The first experiment (n = 10) assessed outcome measures at rest and after a series of five 1-Hz forward and backward head-trunk movements during one-time remifentanil administration. The second experiment (n = 10) determined outcome measures on two days in a controlled crossover design: (1) without movement and (2) with a series of five 1-Hz forward and backward head-trunk bends 30 min after remifentanil start. Nausea was psychophysically quantified (scale from 0 to 10). The third controlled crossover experiment (n = 16) assessed nausea (1) without movement and (2) with head movement;isolated head movements consisting of the three axes of rotation (pitch, roll, yaw) were imposed 20 times at a frequency of 1 Hz in a random, unpredictable order of each of the three axes. All movements were applied manually, passively with amplitudes of about +/- 45 degrees. Results The VOR gain decreased during remifentanil administration (p<0.001),averaging 0.92 +/- 0.05 (mean +/- standard deviation) before, 0.60 +/- 0.12 with, and 0.91 +/- 0.05 after infusion. The average half-life of VOR recovery was 5.3 +/- 2.4 min. 32/36 subjects had no nausea at rest (nausea scale 0.00/0.00 median/interquartile range). Head-trunk and isolated head movement triggered nausea in 64% (p<0.01) with no difference between head-trunk and isolated head movements (nausea scale 4.00/7.25 and 1.00/4.5, respectively). Conclusions Remifentanil reversibly decreases VOR gain at a half-life reflecting the drug's pharmacokinetics. We suggest that the decrease in VOR gain leads to a perceptual mismatch of multisensory input with the applied head movement, which results in nausea, and that, consequently, vigorous head movements should be avoided to prevent opioid-induced nausea

Self-organization of (001) cubic crystal surfaces

Self-organization on crystal surface is studied as a two dimensional spinodal decomposition in presence of a surface stress. The elastic Green function is calculated for a $(001)$ cubic crystal surface taking into account the crystal anisotropy. Numerical calculations show that the phase separation is driven by the interplay between domain boundary energy and long range elastic interactions. At late stage of the phase separation process, a steady state appears with different nanometric patterns according to the surface coverage and the crystal elastic constants

Photocatalytic production of bisabolene from green microalgae mutant: process analysis and kinetic modeling

Currently, algal fuel research has commenced to shift toward genetically engineered mutants able to express and excrete desired products directly into the culture. In this study, a mutant strain of Chlamydomonas reinhardtii, engineered for bisabolene (alternative biodiesel) excretion, was cultivated at different illumination and temperatures to investigate their effects on cell growth and bisabolene production. Moreover, a kinetic model was constructed to identify the desirable conditions for biofuel synthesis. Three original contributions were concluded. First, this work confirmed that bisabolene was partially synthesized independently of biomass growth, indicating its feasibility for continuous production. Second, it was found that while bisabolene synthesis was independent of light intensity, it was strongly affected by temperature, resulting in conflicting desirable conditions for cell growth and product synthesis. Finally, through model prediction, optimal operating conditions were identified for mutant growth and bisabolene synthesis. This study therefore paves the way toward chemostat production and process scale-up

Cellular Recognition of Trimyristoylated Peptide or Enterobacterial Lipopolysaccharide via Both TLR2 and TLR4

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Partitioning of on-demand electron pairs

We demonstrate the high fidelity splitting of electron pairs emitted on demand from a dynamic quantum dot by an electronic beam splitter. The fidelity of pair splitting is inferred from the coincidence of arrival in two detector paths probed by a measurement of the partitioning noise. The emission characteristic of the on-demand electron source is tunable from electrons being partitioned equally and independently to electron pairs being split with a fidelity of 90%. For low beam splitter transmittance we further find evidence of pair bunching violating statistical expectations for independent fermions

DNA extraction from clotted blood in genotyping quality

DNA extraction from frozen blood clots is challenging. Here, the authors applied QIAGEN Clotspin Baskets and the Gentra Puregene Blood Kit for DNA extraction to cellular fraction of 5.5 ml whole blood without anticoagulating additives. The amount and quality of extracted DNA were assessed via spectrophotometer and gel electrophoresis. Results from array-based genotyping were analyzed. All steps were compared with DNA isolated from anticoagulated blood samples from a separate study. The quality and concentration of DNA extracted from clotted blood were comparable to those of DNA extracted from anticoagulated blood. DNA yield was on average 27 μg per ml clotted blood, with an average purity of 1.87 (A260/A280). Genotyping quality was similar for both DNA sources (call rate: 99.56% from clotted vs 99.49% from anticoagulated blood)