A phase field model of discontinuous dynamic recrystallization (PF-DDRX) was employed to investigate grain structure evolution and its impact on mechanical response during thermomechanical processing ...of magnesium alloys. A set of isothermal compression experiments were conducted by thermo-mechanical simulator and used to calibrate the PF-DDRX model parameters such as the critical stress of recrystallization, the activation energy coefficient of dislocation, grain boundary mobility and recrystallization grain nucleation. The grain structure features of polycrystalline magnesium alloys were used to generate the initial grain structure for DDRX simulations. Simulation results show that 1) the ‘necklace’ microstructures, which are often observed in DDRX, form at the earlier stage of recrystallization; and 2) both predicted grain structure and mechanical response are in a reasonable agreement with experimental data. More importantly, the results demonstrate that the proposed methods enable one to establish the relationships between PF-DDRX model parameters and material properties for quantitative prediction and design of grain microstructures and material properties with thermomechanical processes.
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•A PF-DDRX model involving dislocation activities, nucleation and boundary migration has been developed.•Rate sensitive and nucleation activation energy were determined by analyzing experimental flow characteristics.•Actual microstructure details were reproduced by PF model and used as initial grain structure for DRX modeling.•Mechanical response and grain structure can be well predicted for given temperature and strain rate.
The phase III, randomized, open-label ENSURE study (NCT01342965) evaluated first-line erlotinib versus gemcitabine/cisplatin (GP) in patients from China, Malaysia and the Philippines with epidermal ...growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC).
Patients ≥18 years old with histologically/cytologically confirmed stage IIIB/IV EGFR mutation-positive NSCLC and Eastern Cooperative Oncology Group performance status 0-2 were randomized 1:1 to receive erlotinib (oral; 150 mg once daily until progression/unacceptable toxicity) or GP G 1250 mg/m(2) i.v. days 1 and 8 (3-weekly cycle); P 75 mg/m(2) i.v. day 1, (3-weekly cycle) for up to four cycles. Primary end point: investigator-assessed progression-free survival (PFS). Other end points include objective response rate (ORR), overall survival (OS), and safety.
A total of 217 patients were randomized: 110 to erlotinib and 107 to GP. Investigator-assessed median PFS was 11.0 months versus 5.5 months, erlotinib versus GP, respectively hazard ratio (HR), 0.34, 95% confidence interval (CI) 0.22-0.51; log-rank P < 0.0001. Independent Review Committee-assessed median PFS was consistent (HR, 0.42). Median OS was 26.3 versus 25.5 months, erlotinib versus GP, respectively (HR, 0.91, 95% CI 0.63-1.31; log-rank P = .607). ORR was 62.7% for erlotinib and 33.6% for GP. Treatment-related serious adverse events (AEs) occurred in 2.7% versus 10.6% of erlotinib and GP patients, respectively. The most common grade ≥3 AEs were rash (6.4%) with erlotinib, and neutropenia (25.0%), leukopenia (14.4%), and anemia (12.5%) with GP.
These analyses demonstrate that first-line erlotinib provides a statistically significant improvement in PFS versus GP in Asian patients with EGFR mutation-positive NSCLC (NCT01342965).
Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ...ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s
and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona.
Abstract
Spin-valley locking in monolayer transition metal dichalcogenides has attracted enormous interest, since it offers potential for valleytronic and optoelectronic applications. Such an exotic ...electronic state has sparsely been seen in bulk materials. Here, we report spin-valley locking in a Dirac semimetal BaMnSb
2
. This is revealed by comprehensive studies using first principles calculations, tight-binding and effective model analyses, angle-resolved photoemission spectroscopy measurements. Moreover, this material also exhibits a stacked quantum Hall effect (QHE). The spin-valley degeneracy extracted from the QHE is close to 2. This result, together with the Landau level spin splitting, further confirms the spin-valley locking picture. In the extreme quantum limit, we also observed a plateau in the
z
-axis resistance, suggestive of a two-dimensional chiral surface state present in the quantum Hall state. These findings establish BaMnSb
2
as a rare platform for exploring coupled spin and valley physics in bulk single crystals and accessing 3D interacting topological states.
About 3196 EA-type binaries (EAs) were observed by LAMOST by 2017 June 16 and their spectral types were derived. Meanwhile, the stellar atmospheric parameters of 2020 EAs were determined. In this ...paper, those EAs are cataloged and their physical properties and evolutionary states are investigated. The period distribution of EAs suggests that the period limit of tidal locking for the close binaries is about 6 days. It is found that the metallicity of EAs is higher than that of EW-type binaries (EWs), indicating that EAs are generally younger than EWs and they are the progenitors of EWs. The metallicities of long-period EWs ( days) are the same as those of EAs with the same periods, while their values of Log (g) are usually smaller than those of EAs. These support the evolutionary process that EAs evolve into long-period EWs through the combination of angular momentum loss (AML) via magnetic braking and case A mass transfer. For short-period EWs, their metallicities are lower than those of EAs, while their gravitational accelerations are higher. These reveal that they may be formed from cool short-period EAs through AML via magnetic braking with little mass transfer. For some EWs with high metallicities, they may be contaminated by material from the evolution of unseen neutron stars and black holes or they have third bodies that may help them to form rapidly through a short timescale of pre-contact evolution. The present investigation suggests that the modern EW populations may have formed through a combination of these mechanisms.
Objective
To assess the efficacy of metformin in megestrol acetate (MA)‐based fertility‐sparing treatment for patients with atypical endometrial hyperplasia (AEH) and endometrioid endometrial cancer ...(EEC).
Design
A randomised, single‐centre, open‐label, controlled trial conducted between October 2013 and December 2017.
Setting
Shanghai OBGYN Hospital of Fudan University, China.
Population
A total of 150 patients (18–45 years old) with primary AEH or well‐differentiated EEC were randomised into an MA group (n = 74) and an MA plus metformin group (n = 76).
Methods
Patients with AEH or EEC were firstly stratified, then randomised to receive MA (160 mg orally, daily) or MA (160 mg orally, daily) plus metformin (500 mg orally, three times a day).
Main outcomes and measures
The primary efficacy parameter was the cumulate complete response (CR) rate within 16 weeks of treatment (16w‐CR rate); the secondary efficacy parameters were 30w‐CR rate and adverse events.
Results
The 16w‐CR rate was higher in the metformin plus MA group than in the MA‐only group (34.3 versus 20.7%, odds ratio OR 2.0, 95% confidence interval CI 0.89–4.51, P = 0.09) but the difference was more significant in 102 AEH patients (39.6 versus 20.4%, OR 2.56, 95% CI 1.06–6.21, P = 0.04). This effect of metformin was also significant in non‐obese (51.4 versus 24.3%, OR 3.28, 95% CI 1.22–8.84, P = 0.02) and insulin‐sensitive (54.8 versus 28.6%, OR 3.04, 95% CI 1.03–8.97, P = 0.04) subgroups of AEH women. No significant result was found in secondary endpoints.
Conclusion
As a fertility‐sparing treatment, metformin plus MA was associated with a higher early CR rate compared with MA alone in AEH patients.
Tweetable
For AEH patients, metformin plus MA might be a better fertility‐sparing treatment to achieve a higher early CR rate compared with MA alone.
Tweetable
For AEH patients, metformin plus MA might be a better fertility‐sparing treatment to achieve higher early CR rate compared with MA alone.
Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or ...single-crystal aluminum at scales beyond nanotwins. Here, we present the first experimental demonstration of macrodeformation twins in single-crystal aluminum formed under an ultrahigh strain rate (∼10^{6} s^{-1}) and large shear strain (200%) via dynamic equal channel angular pressing. Large-scale molecular dynamics simulations suggest that the frustration of subsonic dislocation motion leads to transonic deformation twinning. Deformation twinning is rooted in the rate dependences of dislocation motion and twinning, which are coupled, complementary processes during severe plastic deformation under ultrahigh strain rates.
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