Quantum Materials Exploration by Sequential Screening Technique of Heteroatomicity

AbstractPredictive materials synthesis is the primary bottleneck in realizing functional and quantum materials. Strategies for synthesis of promising materials are currently identified by time-consuming trial and error and there are no known predictive schemes to design synthesis parameters for materials. We use offline reinforcement learning (RL) to predict optimal synthesis schedules, i.e., a time-sequence of reaction conditions like temperatures and concentrations, for the synthesis of semiconducting monolayer MoS2 using chemical vapor deposition. The RL agent, trained on 10,000 computational synthesis simulations, learned threshold temperatures and chemical potentials for onset of chemical reactions and predicted previously unknown synthesis schedules that produce well-sulfidized crystalline, phase-pure MoS2. The model can be extended to multi-task objectives such as predicting profiles for synthesis of complex structures including multi-phase heterostructures and can predict long-time behavior of reacting systems, far beyond the domain of molecular dynamics simulations, making these predictions directly relevant to experimental synthesis.

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Quantum materials with strong spin-orbit coupling: challenges and opportunities for materials chemists

Journal of Materials Chemistry C ◽

10.1039/d1tc02070f ◽

2021 ◽

Author(s):

Alexander J. Browne ◽

Aleksandra Krajewska ◽

Alexandra Gibbs

Keyword(s):

Transition Metals ◽

Quantum Effect ◽

Orbit Coupling ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Challenges And Opportunities ◽

Quantum Materials ◽

Magnetic States ◽

Strong Spin

Spin-orbit coupling is a quantum effect that can give rise to exotic electronic and magnetic states in the compounds of the 4d and 5d transition metals. Exploratory synthesis, chemical tuning...

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Bi- or multiparametric MRI in a sequential screening program for prostate cancer with PSA followed by MRI? Results from the Göteborg prostate cancer screening 2 trial

European Radiology ◽

10.1007/s00330-021-07907-9 ◽

2021 ◽

Author(s):

Jonas Wallström ◽

Kjell Geterud ◽

Kimia Kohestani ◽

Stephan E. Maier ◽

Marianne Månsson ◽

...

Keyword(s):

Prostate Cancer ◽

Cancer Detection ◽

Screening Program ◽

Prostate Cancer Screening ◽

High Sensitivity ◽

Multiparametric Mri ◽

False Positives ◽

Quality Data ◽

Gadolinium Contrast ◽

Sequential Screening

Abstract Objectives The PIRADS Steering Committee has called for “higher quality data before making evidence-based recommendations on MRI without contrast enhancement as an initial diagnostic work up,” however, recognizing biparametric (bp) MRI as a reasonable option in a low-risk setting such as screening. With bpMRI, more men can undergo MRI at a lower cost and they can be spared the invasiveness of intravenous access. The aim of this study was to assess cancer detection in bpMRI vs mpMRI in sequential screening for prostate cancer (PCa). Methods Within the ongoing Göteborg PCa screening 2 trial, we assessed cancer detection in 551 consecutive participants undergoing prostate MRI. In the same session, readers first assessed bpMRI and then mpMRI. Four targeted biopsies were performed for lesions scored PIRADS 3–5 with bpMRI and/or mpMRI. Results Cancer was detected in 84/551 cases (15.2%; 95% CI: 12.4–18.4) with mpMRI and in 83/551 cases (15.1%; 95% CI: 12.3–18.2%) with bpMRI. The relative risk (RR) for cancer detection with bpMRI compared to mpMRI was 0.99 (95% one-sided CI: > 94.8); bpMRI was non-inferior to mpMRI (10% non-inferiority margin). bpMRI resulted in fewer false positives, 45/128 (35.2%), compared to mpMRI, 52/136 (38.2%), RR = 0.92; 95% CI: 0.84–0.98. Of 8 lesions scored positive only with mpMRI, 7 were false positives. The PPV for MRI and targeted biopsy was 83/128 (64.8%) for bpMRI and 84/136 (61.8%) for mpMRI, RR = 1.05, 95% CI: 1.01–1.10. Conclusions In a PSA-screened population, bpMRI was non-inferior to mpMRI for cancer detection and resulted in fewer false positives. Key Points • In screening for prostate cancer with PSA followed by MRI, biparametric MRI allows radiologists to detect an almost similar number of prostate cancers and score fewer false positive lesions compared to multiparametric MRI. • In a screening program, high sensitivity should be weighed against cost and risks for healthy men; a large number of men can be saved the exposure of gadolinium contrast medium by adopting biparametric MRI and at the same time allowing for a higher turnover in the MRI room.

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