198 research outputs found
Integrating planar circuits with superconducting 3D microwave cavities using tunable low-loss couplers
We design and test a low-loss interface between superconducting 3-dimensional
microwave cavities and 2-dimensional circuits, where the coupling rate is
highly tunable. This interface seamlessly integrates a magnetic antenna and a
Josephson junction based coupling element with a cavity, and we demonstrate
that the introduced loss from this integration only limits the quality factor
to 4.5 million. The cavity external coupling rate can then be tuned from
negligibly small to over 3 orders of magnitude larger than the internal loss
rate with a characteristic time of 3.2 ns. This switching speed does not impose
additional limits on the coupling rate because it is much faster than the
coupling rate. Moreover, the coupler can be controlled by baseband signals to
avoid interference with microwave signals near the cavity or qubit frequencies.
Finally, the coupling element introduces a 0.04 Hz/photon self-Kerr
nonlinearity to the cavity, remaining linear in high photon number operations
Microwave Spin Control of a Tin-Vacancy Qubit in Diamond
The negatively charged tin-vacancy (SnV-) center in diamond is a promising
solid-state qubit for applications in quantum networking due to its high
quantum efficiency, strong zero phonon emission, and reduced sensitivity to
electrical noise. The SnV- has a large spin-orbit coupling, which allows for
long spin lifetimes at elevated temperatures, but unfortunately suppresses the
magnetic dipole transitions desired for quantum control. Here, by use of a
naturally strained center, we overcome this limitation and achieve
high-fidelity microwave spin control. We demonstrate a pi-pulse fidelity of up
to 99.51+/0.03%$ and a Hahn-echo coherence time of T2echo = 170.0+/-2.8
microseconds, both the highest yet reported for SnV- platform. This performance
comes without compromise to optical stability, and is demonstrated at 1.7
Kelvin where ample cooling power is available to mitigate drive induced
heating. These results pave the way for SnV- spins to be used as a building
block for future quantum technologies
Comparative Survival of Asian and White Metastatic Castration-Resistant Prostate Cancer Men Treated With Docetaxel
There are few data regarding disparities in overall survival (OS) between Asian and white men with metastatic castration-resistant prostate cancer (mCRPC). We compared OS of Asian and white mCRPC men treated in phase III clinical trials with docetaxel and prednisone (DP) or a DP-containing regimen. Individual participant data from 8820 men with mCRPC randomly assigned on nine phase III trials to receive DP or a DP-containing regimen were combined. Men enrolled in these trials had a diagnosis of prostate adenocarcinoma. The median overall survival was 18.8 months (95% confidence interval [CI] = 17.4 to 22.1 months) and 21.2 months (95% CI = 20.8 to 21.7 months) for Asian and white men, respectively. The pooled hazard ratio for death for Asian men compared with white men, adjusted for baseline prognostic factors, was 0.95 (95% CI = 0.84 to 1.09), indicating that Asian men were not at increased risk of death. This large analysis showed that Asian men did not have shorter OS duration than white men treated with docetaxel
Risk factors for late bowel and bladder toxicities in NRG Oncology prostate cancer trials of high-risk patients: A meta-analysis of physician-rated toxicities
Purpose: A meta-analysis of sociodemographic variables and their association with late (\u3e180 days from start of radiation therapy[RT]) bowel, bladder, and clustered bowel and bladder toxicities was conducted in patients with high-risk (clinical stages T2c-T4b or Gleason score 8-10 or prostate-specific antigen level \u3e20) prostate cancer.
Methods and materials: Three NRG trials (RTOG 9202, RTOG 9413, and RTOG 9406) that accrued from 1992 to 2000 were used. Late toxicities were measured with the Radiation Therapy Oncology Group Late Radiation Morbidity Scale. After controlling for study, age, Karnofsky Performance Status, and year of accrual, sociodemographic variables were added to the model for each outcome variable of interest in a stepwise fashion using the Fine-Gray regression models with an entry criterion of 0.05.
Results: A total of 2432 patients were analyzed of whom most were Caucasian (76%), had a KPS score of 90 to 100 (92%), and received whole-pelvic RT+HT (67%). Of these patients, 13 % and 16% experienced late grade ≥2 bowel and bladder toxicities, respectively, and 2% and 3% experienced late grade ≥3 bowel and bladder toxicities, respectively. Late grade ≥2 clustered bowel and bladder toxicities were seen in approximately 1% of patients and late grade ≥3 clustered toxicities were seen in 2 patients (
Conclusions: Patients with high-risk prostate cancer who receive whole-pelvic RT+LT HT are more likely to have a grade ≥2 bowel toxicity than those who receive prostate-only RT. LT bowel and bladder toxicities were infrequent. Future studies will need to confirm these findings utilizing current radiation technology and patient-reported outcomes
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