Mechanical properties of nanophase metals

Nanophase metals have grain-size dependent mechanical properties that are significantly different than those of their coarse-grained counterparts. Pure metals are much stronger and apparently less ductile than conventional ones; intermetallics are also strengthened, but they tend toward increased ductility at the smallest grain sizes. These property changes are primarily related to grain size limitations, but they are also affected by the large percentage of atoms in grain boundaries and other microstructural features. Strengthening appears to result from a limitation of dislocation activity, while increased ductility probably relates to grain boundary sliding. A brief overview of our present understanding of the mechanical properties of nanophase metals is presented

Hall Effect in the coma of 67P/Churyumov-Gerasimenko

Magnetohydrodynamics simulations have been carried out in studying the solar wind and cometary plasma interactions for decades. Various plasma boundaries have been simulated and compared well with observations for comet 1P/Halley. The Rosetta mission, which studies comet 67P/Churyumov-Gerasimenko, challenges our understanding of the solar wind and comet interactions. The Rosetta Plasma Consortium observed regions of very weak magnetic field outside the predicted diamagnetic cavity. In this paper, we simulate the inner coma with the Hall magnetohydrodynamics equations and show that the Hall effect is important in the inner coma environment. The magnetic field topology becomes complex and magnetic reconnection occurs on the dayside when the Hall effect is taken into account. The magnetic reconnection on the dayside can generate weak magnetic filed regions outside the global diamagnetic cavity, which may explain the Rosetta Plasma Consortium observations. We conclude that the substantial change in the inner coma environment is due to the fact that the ion inertial length (or gyro radius) is not much smaller than the size of the diamagnetic cavity.Comment: 23 pages, 6 figur

Low CO/CO₂ ratios of comet 67P measured at the Abydos landing site by the <i>Ptolemy</i> mass spectrometer

Comets are generally considered to contain the best-preserved material from the beginning of our planetary system, although the mechanism of their formation and subsequent evolution are still poorly understood. Here we report the direct in situ measurement of H2O, CO, and CO2 by the Ptolemy mass spectrometer onboard the Philae lander, part of the European Space Agency’s Rosetta mission, at the Abydos site of the Jupiter-family comet 67P/Churyumov-Gerasimenko. A CO/CO2 ratio of around 0.07 ± 0.04 is found at the surface of the comet, a value substantially lower than the one measured by ROSINA in the coma. Such a major difference is a potential indication of heterogeneity of the nucleus and not of changes in the CO/CO2 ratio of the coma with radial distance

A role for artificial intelligence in molecular imaging of infection and inflammation

The detection of occult infections and low-grade inflammation in clinical practice remains challenging and much depending on readers' expertise. Although molecular imaging, like [F-18]FDG PET or radiolabeled leukocyte scintigraphy, offers quantitative and reproducible whole body data on inflammatory responses its interpretation is limited to visual analysis. This often leads to delayed diagnosis and treatment, as well as untapped areas of potential application. Artificial intelligence (AI) offers innovative approaches to mine the wealth of imaging data and has led to disruptive breakthroughs in other medical domains already. Here, we discuss how AI-based tools can improve the detection sensitivity of molecular imaging in infection and inflammation but also how AI might push the data analysis beyond current application toward predicting outcome and long-term risk assessment

Interim analysis of the REASSURE (Radium-223 alpha Emitter Agent in non-intervention Safety Study in mCRPC popUlation for long-teRm Evaluation) study: patient characteristics and safety according to prior use of chemotherapy in routine clinical practice

Purpose: REASSURE is a global, prospective, non-interventional study to assess long-term safety of radium-223 in patients with bone metastatic castration-resistant prostate cancer. Here we report an interim analysis of patients according to previous use of chemotherapy. Methods: Radium-223 was administered in routine clinical practice. Interim safety analysis was planned after enrolment of the first 600 patients. Patient characteristics and safety data by previous administration of chemotherapy (docetaxel and/or cabazitaxel) were investigated. Results: This interim analysis included 583 patients. Median duration of observation was 7 months (range, 0–20). Nineteen patients treated with concomitant chemotherapy were excluded, 564 (97%) were eligible for exploratory analysis according to prior use of chemotherapy; 190 (34%) had previously received and completed chemotherapy, and 374 (66%) had not. In the prior versus no prior chemotherapy group, a higher proportion of patients had an Eastern Cooperative Oncology Group performance status of ≥2 (22% vs 11%) and > 20 metastatic lesions (26% vs 15%), median alkaline phosphatase (162.0 vs 115.0 U/L) and prostate-specific antigen (132.0 vs 40.2 ng/mL) levels were higher, and a lower proportion completed 6 radium-223 injections (45% vs 63%). Drug-related treatment-emergent adverse events (TEAEs) occurred in 63 and 48%, and haematological drug-related TEAEs in 21 and 9% of patients who had or had not previously received chemotherapy. Four drug-related deaths were reported, all in the prior chemotherapy group. Conclusions: The short-term safety profile of radium-223 in routine clinical practice was comparable to other clinical studies, irrespective of prior chemotherapy use. Haematological TEAEs occurred more frequently in the prior chemotherapy group, presumably due to decreased bone marrow function as a consequence of more advanced disease and prior exposure to cytotoxic therapy. Patients who had not previously received chemotherapy appeared to have a lower burden of disease at baseline, and a lower proportion discontinued radium-223 treatment.Purpose: REASSURE is a global, prospective, non-interventional study to assess long-term safety of radium-223 in patients with bone metastatic castration-resistant prostate cancer. Here we report an interim analysis of patients according to previous use of chemotherapy. Methods: Radium-223 was administered in routine clinical practice. Interim safety analysis was planned after enrolment of the first 600 patients. Patient characteristics and safety data by previous administration of chemotherapy (docetaxel and/or cabazitaxel) were investigated. Results: This interim analysis included 583 patients. Median duration of observation was 7&nbsp;months (range, 0–20). Nineteen patients treated with concomitant chemotherapy were excluded, 564 (97%) were eligible for exploratory analysis according to prior use of chemotherapy; 190 (34%) had previously received and completed chemotherapy, and 374 (66%) had not. In the prior versus no prior chemotherapy group, a higher proportion of patients had an Eastern Cooperative Oncology Group performance status of ≥2 (22% vs 11%) and &gt; 20 metastatic lesions (26% vs 15%), median alkaline phosphatase (162.0 vs 115.0&nbsp;U/L) and prostate-specific antigen (132.0 vs 40.2&nbsp;ng/mL) levels were higher, and a lower proportion completed 6 radium-223 injections (45% vs 63%). Drug-related treatment-emergent adverse events (TEAEs) occurred in 63 and 48%, and haematological drug-related TEAEs in 21 and 9% of patients who had or had not previously received chemotherapy. Four drug-related deaths were reported, all in the prior chemotherapy group. Conclusions: The short-term safety profile of radium-223 in routine clinical practice was comparable to other clinical studies, irrespective of prior chemotherapy use. Haematological TEAEs occurred more frequently in the prior chemotherapy group, presumably due to decreased bone marrow function as a consequence of more advanced disease and prior exposure to cytotoxic therapy. Patients who had not previously received chemotherapy appeared to have a lower burden of disease at baseline, and a lower proportion discontinued radium-223 treatment

Atomic-scale modeling of the deformation of nanocrystalline metals

Nanocrystalline metals, i.e. metals with grain sizes from 5 to 50 nm, display technologically interesting properties, such as dramatically increased hardness, increasing with decreasing grain size. Due to the small grain size, direct atomic-scale simulations of plastic deformation of these materials are possible, as such a polycrystalline system can be modeled with the computational resources available today. We present molecular dynamics simulations of nanocrystalline copper with grain sizes up to 13 nm. Two different deformation mechanisms are active, one is deformation through the motion of dislocations, the other is sliding in the grain boundaries. At the grain sizes studied here the latter dominates, leading to a softening as the grain size is reduced. This implies that there is an ``optimal'' grain size, where the hardness is maximal. Since the grain boundaries participate actively in the deformation, it is interesting to study the effects of introducing impurity atoms in the grain boundaries. We study how silver atoms in the grain boundaries influence the mechanical properties of nanocrystalline copper.Comment: 10 pages, LaTeX2e, PS figures and sty files included. To appear in Mater. Res. Soc. Symp. Proc. vol 538 (invited paper). For related papers, see http://www.fysik.dtu.dk/~schiotz/publist.htm

CN and OH emissions in the 67P/Churyumov-Gerasimenko coma with Rosetta/VIRTIS-M spectrometer

Observations with the visible channel of the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on board Rosetta taken when the spacecraft was at a distance of 80-140 km from 67P/Churyumov-Gerasimenko (67P/C-G) allowed the detection of daughter gaseous species in its inner coma. The detection of the violet doublet emission of CN at 388.3 nm has occurred during the coma monitoring campaign in November-December 2015, when the instrument has operated with long integration times (50 s) necessary to boost the instrumental SNR and detect these faint emissions. Other features, like the C3 and C2 signatures around 420-480 nm, might possibly be visible in few cases but with a very low intensity. For this reason, we concentrate our analysis in the spectral region from 250 to 450 nm, where the detector sensitivity allows the positive detection of the above mentioned CN violet line at 388.3 nm, and the OH doublet emission at 309 nm. The CN emission at 388.3 nm is observed on both the day and night sides of 67P/C-G with a higher intensity on the dayside. In addition, at a preliminary analysis, the hydroxyl doublet emission intensity seems to be comparable to the violet CN line. The same emissions were also identified in spectra acquired using ground-based facilities, when the comet had just passed the perihelion (Fitzsimmons et al., 2016). These gaseous species emissions appear well contrasted with respect to the dust broad continuum, preferentially observed on the dayside. Distribution and variability of the OH and CN band intensities will be discussed with respect to observation parameters

Interim analysis of the REASSURE (Radium-223 alpha Emitter Agent in non-intervention Safety Study in mCRPC popUlation for long-teRm Evaluation) study : patient characteristics and safety according to prior use of chemotherapy in routine clinical practice

Purpose: REASSURE is a global, prospective, non-interventional study to assess long-term safety of radium-223 in patients with bone metastatic castration-resistant prostate cancer. Here we report an interim analysis of patients according to previous use of chemotherapy. Methods: Radium-223 was administered in routine clinical practice. Interim safety analysis was planned after enrolment of the first 600 patients. Patient characteristics and safety data by previous administration of chemotherapy (docetaxel and/or cabazitaxel) were investigated. Results: This interim analysis included 583 patients. Median duration of observation was 7&nbsp;months (range, 0\u201320). Nineteen patients treated with concomitant chemotherapy were excluded, 564 (97%) were eligible for exploratory analysis according to prior use of chemotherapy; 190 (34%) had previously received and completed chemotherapy, and 374 (66%) had not. In the prior versus no prior chemotherapy group, a higher proportion of patients had an Eastern Cooperative Oncology Group performance status of 652 (22% vs 11%) and &gt; 20 metastatic lesions (26% vs 15%), median alkaline phosphatase (162.0 vs 115.0&nbsp;U/L) and prostate-specific antigen (132.0 vs 40.2&nbsp;ng/mL) levels were higher, and a lower proportion completed 6 radium-223 injections (45% vs 63%). Drug-related treatment-emergent adverse events (TEAEs) occurred in 63 and 48%, and haematological drug-related TEAEs in 21 and 9% of patients who had or had not previously received chemotherapy. Four drug-related deaths were reported, all in the prior chemotherapy group. Conclusions: The short-term safety profile of radium-223 in routine clinical practice was comparable to other clinical studies, irrespective of prior chemotherapy use. Haematological TEAEs occurred more frequently in the prior chemotherapy group, presumably due to decreased bone marrow function as a consequence of more advanced disease and prior exposure to cytotoxic therapy. Patients who had not previously received chemotherapy appeared to have a lower burden of disease at baseline, and a lower proportion discontinued radium-223 treatment

Radium-223 for primary bone metastases in patients with hormone-sensitive prostate cancer after radical prostatectomy

Radium-223 dichloride (Ra-223) is the first bone-targeting agent showing improvement in overall survival in patients with castration-resistant prostate cancer (CRPC) and bone metastases. We aimed to assess feasibility of Ra-223 treatment in patients with metastatic hormone-sensitive prostate cancer (mHSPC). Ten patients with primary bone metastases received Ra-223 following radical prostatectomy (RP). Changes in alkaline phosphatase (ALP) and prostate-specific antigen (PSA) were recorded, while pain intensity was evaluated using the self-reporting Brief Pain Inventory (BPI) questionnaire. Bone scintigraphy (BS) was performed to assess treatment response. Seven patients completed six cycles of Ra-223. Discontinuation was due to leuko-and lymphopenia, progressive lymph node metastasis or newly diagnosed liver metastasis. Treatment-related adverse events occurred in three patients and included leuko-and lymphopenia, fatigue, abdominal discomfort and nausea. Overall, a median decrease of 28% in ALP and a median decrease of 83% in PSA were noted at follow-up. However, PSA progressed in five patients at follow-up. Improvement of pain was observed in all patients (median decrease of 36% after 3 cycles and of 40% at the end of therapy). On BS, three patients showed remission, four had stable disease, and one showed progressive disease at follow-up. Our results suggest that Ra-223 for primary bone metastases in patients with mHSPC after RP is feasible and alleviates pain. ALP, rather than PSA, may be a good marker for assessing treatment response. Ra-223 could therefore be taken into consideration as part of a multimodal approach for carefully selected patients with advanced prostate cancer