Restricted single isocenter for multiple targets dynamic conformal arc (RSIMT DCA) technique for brain stereotactic radiosurgery (SRS) planning.

In stereotactic radiosurgery (SRS), the multiple isocenters for multiple targets dynamic conformal arc (MIMT DCA) technique is traditionally used to treat multiple brain metastases, with one isocenter for each target. The single isocenter for multiple targets (SIMT) technique has recently been adopted to reduce the treatment time at the cost of plan quality. The objective of this study was to develop a restricted single isocenter for multiple targets DCA (RSIMT DCA) technique that can significantly reduce the treatment time but still maintain similar plan quality as the MIMT DCA technique.Treating multiple brain metastases with a single isocenter poses a challenge to SRS planning using DCA beams that are intrinsically 3D and do not modulate the beam intensity to spare the normal tissue between targets. To address this obstacle, we have developed a RSIMT DCA technique and used it to treat SRS patients with multiple brain metastases since February 2015. This planning approach is similar to the SIMT technique except that the number of targets for each isocenter is restricted and the distance between the isocenter and target is limited. In this technique, the targets are first split into batches so that all targets in a batch are within a chosen distance (e.g., 7 cm) of each other. All targets in a batch are combined into one target and the geometric center of the combined target is the isocenter for the group of DCA beams associated with that batch. Each DCA group typically consists of 3-4 DCA beams to irradiate 1-3 targets. For each DCA beam, the collimator angle is adjusted to minimize the exposure of normal tissue between targets. The dose of each treatment group is normalized so that the maximal point dose to the combined target is 125% of the prescription dose, which is equivalent to normalize the prescription dose to 80% isodose line. If the maximal point dose of a target is 95% and V19Gy=100%) was achieved for all plans using either technique. Most PTVs have a maximal point dose between 24.9 and 25.1 Gy, with 2 PTVs between 24.5 and 24.9 Gy. Overall, the plan quality was slightly better for the MIMT DCA technique and the normalized difference was statistically significantly larger than 0 for all investigated dose quality indexes. The normalized difference of body mean dose and conformity index (CI) between the RSIMT and MIMT techniques was respectively 4.2% (p=0.002) and 9.4% (p=0.001), indicating similar plan quality globally and in the high dose area. The difference was more pronounced for the mid-to-low dose spillage with the ratios of V12Gy and V10Gy/VPTV being 13.9% (p=3.8×10-6) and 14.9% (p=1.3×10-5), respectively. The treatment time was reduced by 30%-50% with the RSIMT DCA technique.The RSIMT DCA technique can produce satisfactory SRS plans for treating multiple targets and can significantly reduce the treatment time

Strain path dependency in incremental sheet-bulk metal forming

Incremental sheet-bulk metal forming (iSBMF) enables the manufacture of functional lightweight components featuring a load-adapted shape with a high material efficiency. The flexibility of the incremental forming process allows for the modification of the strain path through the adjustment of the tool motion while maintaining the final product geometry. These modifications generate both a different strain hardening and damage evolution. In this paper, a numerical and experimental investigation of the different strain paths is carried out to identify their impact on the resulting load capacity of gears. In experiments on the quasistatic load capacity of the gears it is validated that forming of gears with a strain path showing a reduced damage potential leads to a 50% higher load capacity compared to the most unfavorable strain path. Moreover, all investigated load paths present load changes that have to be taken into account in numerical modeling of iSBMF processes. Therefore, a new approach for a material characterization under multiple load changes and high effective plastic strain is tested. Compared to numerical modeling with a characterized monotonically flow curve, this approach decreases the deviation force prediction by around 80% without increasing the calculation time

Organization of networks with tagged nodes and biased links: a priori distinct communities. The case of Intelligent Design Proponents and Darwinian Evolution Defenders

Among topics of opinion formation it is of interest to observe the characteristics of networks with a priori distinct communities. As an illustration, we report on the citation network(s) unfolded in the recent decades through web available works belonging to selected members of the Neocreationist and Intelligent Design Proponents (IDP) and the Darwinian Evolution Defenders (DED) communities. An adjacency matrix of tagged nodes is first constructed; it is not symmetric. A generalization of considerations pertaining to the case of networks with biased links, directed or undirected, is thus presented. The main characteristic coefficients describing the structure of such partially directed networks with tagged nodes are outlined. The structural features are discussed searching for statistical aspects, equivalence or not of subnetworks through the degree distributions, each network assortativity, the global and local clustering coefficients and the Average Overlap Indices. The various closed and open triangles made from nodes, moreover distinguishing the community, are especially listed to calculate the clustering characteristics. The distribution of elements in the rectangular submatrices are specially examined since they represent inter-community connexions. The emphasis being on distinguishing the number of vertices belonging to a given community. Using such informations one can distinguish between opinion leaders, followers and main rivals and briefly interpret their relationships through psychological-like conditions intrinsic to behavior rules in either community. Considerations on other controversy cases with similar social constraints are outlined, as well as suggestions on further, more general, work deduced from our observations on such networks.Comment: 40 pages, 61 references, 7 Tables, 11 Figures, 2 Appendices (giving the adjacency matrices

Evidence for the Role of Mindfulness in Cancer: Benefits and Techniques.

Mindfulness is being used increasingly in various aspects of cancer management. Benefits of mindfulness practices are being observed to manage the adverse effects of treatment, symptoms from cancer progression, and the cost-effectiveness compared to conventional contemporary management strategies. In this review article, we present clinical trial data showing the benefits of mindfulness in various aspects of cancer management as well as techniques that have been commonly used in this practice

Spatial clustering of defect luminescence centers in Si-doped low resistivity Al0.82Ga0.18N

A series of Si-doped AlN-rich AlGaN layers with low resistivities was characterized by a combination of nanoscale imaging techniques. Utilizing the capability of scanning electron microscopy to reliably investigate the same sample area with different techniques, it was possible to determine the effect of doping concentration, defect distribution, and morphology on the luminescence properties of these layers. Cathodoluminescence shows that the dominant defect luminescence depends on the Si-doping concentration. For lower doped samples, the most intense peak was centered between 3.36 eV and 3.39 eV, while an additional, stronger peak appears at 3 eV for the highest doped sample. These peaks were attributed to the (VIII-ON)2− complex and the V3−III vacancy, respectively. Multimode imaging using cathodoluminescence, secondary electrons, electron channeling contrast, and atomic force microscopy demonstrates that the luminescence intensity of these peaks is not homogeneously distributed but shows a strong dependence on the topography and on the distribution of screw dislocations.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeBMBF, 13N12587, Photonische Plattformtechnologie zur ultrasensitiven und hochspezifischen biochemischen Sensorik auf Basis neuartiger UV-LEDs (UltraSens

Magnitude and Timing of Extreme Continental Extension, Central Death Valley Region, California

New geochronologic, stratigraphic, and sedimentologic data indicate extreme late Cenozoic extension across the central Death Valley region (fig. 9). ^(40)Ar/^(39)Ar geochronology of sanidine from tuffs intercalated with steeply tilted sediments along the eastern margin of the central Death Valley region, including sections near Chicago Pass and at Eagle Mountain, indicates deposition from approximately 15 to 11.7 Ma (fig. 10). Clasts of marble, orthoquartzite, fusilinid limestone, and leucogabbro are prominent at both locations. The only known source in the Death Valley region for this clast assemblage is in the southern Cotton wood Mountains, more than 100 km away on the western flank of the Death Valley region. U/Pb geochronology of baddeleyite confirms that leucogabbro clasts from both sections have the same igneous crystallization age (~180 Ma) as the leucogabbroic phase of the Hunter Mountain batholith, in the southern Cottonwood Mountains. The sediments include debris flows, flood deposits, and monolithic boulder beds of large leucogabbro clasts (>1 m), suggesting deposition in an alluvial fan setting. Sedimentary transport of these deposits is unlikely to have exceeded 20 km. Restoration of the Eagle Mountain and Chicago Valley deposits to a position just east of the southern Cotton wood Mountains results in approximate net translations of 80 km and 104 km, respectively, at an azimuth of N. 67° W. (fig. 11). This suggests overall extension magnitudes of at least 500 percent across the Death Valley region since 12 Ma, with strain rates that approached 10^(-14)/s during maximum extension. These results support previous reconstructions based on isopachs and Mesozoic structural features. (See, for example, Wernicke and others, 1988.

Athermalization of the Lasing Wavelength in Vertical-Cavity Surface-Emitting Lasers

A concept for vertical-cavity surface-emitting lasers (VCSELs) is proposed and demonstrated to obtain a lasing wavelength with unprecedented temperature stability. The concept is based on incorporating a dielectric material with a negative thermo-optic coefficient, dn/dT, in the distributed Bragg reflectors (DBRs) to compensate the positive dn/dT of the semiconductor cavity. In a short cavity, the optical field has a significant overlap with the DBRs, and the redshift of the lasing wavelength caused by the semiconductor cavity can be compensated by the negative dn/dT of the DBRs. Here, proof of this concept is presented for optically-pumped VCSELs emitting at 310 nm, demonstrating a lasing wavelength that even blueshifts by less than 0.1\ua0nm over an 80 \ub0C range with a maximum slope of –3.4\ua0pm K−1. This is to be compared with a redshift of 1–1.5\ua0nm over the same temperature range reported for III-nitride blue-emitting VCSELs. Furthermore, this method can also be implemented in VCSELs with longer cavity lengths by including a dielectric layer between the semiconductor and the DBR. The approach used here to obtain a temperature-stable lasing wavelength is generic and can therefore be applied to VCSELs in all material systems and lasing\ua0wavelengths

Global Positioning System constraints on fault slip rates in the Death Valley region, California and Nevada

We estimated horizontal velocities at 15 locations in the vicinity of Yucca Mountain, Nevada, from Global Positioning System surveys conducted between 1991 and 1996. We used these velocity estimates to infer slip rates on two major Quaternary faults within the eastern California shear zone (ECSZ), the Hunter Mountain and Death Valley faults. The sum of slip rates across the two faults is well determined at 5 ± 1 mm/yr (1-σ). Between 3 to 5 mm/yr of this motion appears to be accommodated along the Death Valley fault, implying 30–50 m of strain accumulation over the next 10,000 yr. If so, there is potential for 5 to 10 M_(w) 6.5–7.5 earthquakes during this period, a finding consistent with paleoseismological studies of the fault zone. Yucca Mountain, which lies 50 km east of the ECSZ, is the proposed location for the disposal of high-level nuclear waste in the United States