Background
Although some retrospective studies have suggested the value of adjuvant therapy, no recommended standard exists in bile duct cancer. The aim of this study was to test the hypothesis that ...adjuvant gemcitabine chemotherapy would improve survival probability in resected bile duct cancer.
Methods
This was a randomized phase III trial. Patients with resected bile duct cancer were assigned randomly to gemcitabine and observation groups, which were balanced with respect to lymph node status, residual tumour status and tumour location. Gemcitabine was given intravenously at a dose of 1000 mg/m2, administered on days 1, 8 and 15 every 4 weeks for six cycles. The primary endpoint was overall survival, and secondary endpoints were relapse‐free survival, subgroup analysis and toxicity.
Results
Some 225 patients were included (117 gemcitabine, 108 observation). Baseline characteristics were well balanced between the gemcitabine and observation groups. There were no significant differences in overall survival (median 62·3 versus 63·8 months respectively; hazard ratio 1·01, 95 per cent c.i. 0·70 to 1·45; P = 0·964) and relapse‐free survival (median 36·0 versus 39·9 months; hazard ratio 0·93, 0·66 to 1·32; P = 0·693). There were no survival differences between the two groups in subsets stratified by lymph node status and margin status. Although haematological toxicity occurred frequently in the gemcitabine group, most toxicities were transient, and grade 3/4 non‐haematological toxicity was rare.
Conclusion
The survival probability in patients with resected bile duct cancer was not significantly different between the gemcitabine adjuvant chemotherapy group and the observation group. Registration number: UMIN 000000820 (http://www.umin.ac.jp/).
No advantage
•A non-parametric design method for railway wheel webs is evaluated.•The two types of railway wheels in Japan are optimized using the traction method.•The method is shown to provide a more efficient ...and effective design.•Improve wheel design can lead to reduced maintenance and manufacturing costs.
Railway wheels are safety-critical components with complex stress states that make parametric design difficult. Accordingly, this study evaluated a non-parametric shape optimization technique using the traction method for the fatigue design of railway wheel webs, considering design specifications or factors such as the position and size of the rim or hub as constraints. Reduced models were then employed to consider the influence of wheel wear on the stress state of the web to further inform design. The findings of this study indicate that the traction method can be successfully used to optimize the geometry of railway wheel webs according to stress, geometric, or mass constraints.
We investigate the forces and atmosphere‐ionosphere coupling that create atmospheric dynamo currents using two rockets launched nearly simultaneously on 4 July 2013 from Wallops Island (USA), during ...daytime Sq conditions with ΔH of −30 nT. One rocket released a vapor trail observed from an airplane which showed peak velocities of >160 m/s near 108 km and turbulence coincident with strong unstable shear. Electric and magnetic fields and plasma density were measured on a second rocket. The current density peaked near 110 km exhibiting a spiral pattern with altitude that mirrored that of the winds, suggesting the dynamo is driven by tidal forcing. Such stratified currents are obscured in integrated ground measurements. Large electric fields produced a current opposite to that driven by the wind, believed created to minimize the current divergence. Using the observations, we solve the dynamo equation versus altitude, providing a new perspective on the complex nature of the atmospheric dynamo.
Plain Language Summary
Two rockets with scientific instruments were launched in the middle of the day to study the upper atmosphere and how it interacts with the ionosphere. The rockets ascended to altitudes of about 140 km—just high enough to gather the necessary data—before coming back down along parabolic trajectories. A vapor trail released by one rocket was photographed on an airplane and showed the upper atmosphere moving at very large speeds, much larger than previously believed. In fact, these winds were so large and changed speed so quickly that in some places the upper atmosphere became turbulent. Instruments on the second rocket gathered information about the ionosphere, including the number of ions present and how the currents and electric fields associated with those charged particles varied with altitude, particularly where the winds were strongest. The winds and currents both displayed a spiral pattern with altitude indicative that they were driven by atmospheric forcing from below. By combining all of these measurements, we are able to better determine what drives the worldwide system of currents at the base of the ionosphere. This “daytime dynamo” is a fundamental part of our natural world, swirling high above us and changing every day.
Key Points
Comprehensive observations of the daytime Sq dynamo electrodynamics have been gathered for the first time
Observed daytime winds in the dynamo region are much larger than expected yet their currents are reduced by those of DC electric fields
Winds and currents exhibit an interleaved spiral pattern indicative of tidal forcing
Anthropogenic CO2 uptake drives ocean acidification and so decreases the calcium carbonate (CaCO3) saturation state (Ω). Undersaturation of surface water with respect to aragonite‐type CaCO3 was ...first reported for 2008 in the Canada Basin, preceding other open ocean basins. This study reveals interannual variation of Ω in the surface Canada Basin before and after 2008. A rapid decrease of Ω occurred during 2003–2007 at a rate of −0.09 year−1, 10 times faster than other open oceans. This was due to melting and retreat of sea ice, which diluted surface water and enhanced air‐sea CO2 exchange. After 2007, Ω did not further decrease, despite increasing atmospheric CO2 and continued sea ice retreat. A weakened dilution effect from sea ice melt and stabilized air‐sea CO2 disequilibrium state is the main reason for this stabilization of Ω. Aragonite undersaturation has been observed for the last 11 years, and aragonite‐shelled organisms may be threatened.
Plain Language Summary
Anthropogenic CO2 absorbed by the ocean results in decreases in pH and the calcium carbonate saturation state of seawater (Ω). This is ocean acidification (OA). In the Arctic Ocean, the most susceptible region in the world to OA, melting sea ice and anthropogenic CO2 absorption promote both OA and the decline of Ω. This study used observations collected over the last two decades to estimate Ω interannual variation in the surface waters of the Beaufort Gyre and to understand the effects of different factors: atmospheric CO2, air‐sea CO2 disequilibrium, seawater temperature, and dilution by sea ice melt. The results showed that Ω decreased rapidly from 2003 to 2007 at a rate ~10 times faster than other open ocean basins, resulting in undersaturation of aragonite‐type calcium carbonate. After 2007 Ω was stable, rather than continuously decreasing with increasing atmospheric CO2. The rapid decrease and then stabilization of Ω before and after 2007 are related to strong and then weakened dilution effects from sea ice melting. In addition, enhanced and then stabilized air‐sea CO2 exchange conditions contributed to variation of Ω. Aragonite undersaturation has now been observed for the last 11 years which may threaten shelled organisms residing in the Canada Basin.
Key Points
Aragonite saturation state (Ω) of surface water declined rapidly at −0.09 year−1 from 2003 to 2007, 10 times faster than other open oceans
Aragonite undersaturation has been observed for the last 11 years, beginning in 2006
After 2007, mean Ω has stabilized due to a decrease of sea ice meltwater content and stabilization of the air‐sea CO2 disequilibrium state
Supercurrent in the quantum Hall regime Amet, F.; Ke, C. T.; Borzenets, I. V. ...
Science (American Association for the Advancement of Science),
05/2016, Letnik:
352, Številka:
6288
Journal Article
Recenzirano
Odprti dostop
A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH ...regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.
PDF
