Quantum bath suppression in a superconducting circuit by immersion cooling.

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK - far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins - factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid 3He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The 3He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors.

Effects of endocrine therapy on steroid-receptor content of breast cancer.

In order to determine the mechanisms of relapse following response to endocrine therapy, we have measured the oestrogen receptor (RE) content of biopsies of breast cancer in patients receiving various types of endocrine treatment. RE content fell in responding (means of 260.2 to 12 fmol/mg protein) and in nonresponding (means of 155.1 to 31.8 fmol/mg protein) patients who had measurable receptor at the start of treatment. Some of these patients, and a further group of responders to endocrine therapy, were monitored until relapse. Tumour biopsies at the time of relapse showed that 10/14 tumour samples contained significant RE (mean of 86.7 fmol/mg protein; range less than 10-271 fmol/mg protein) after successful endocrine therapy. No relationship could be found between RE content and plasma gonadotrophin or steroid-hormone concentration, but the fall in RE content correlated with reduced numbers of tumour cells in the biopsy. These results indicate that relapse following successful endocrine therapy in breast cancer does not appear to be due to the emergence of RE-negative tumour cells. The fall in RE content during response to endocrine therapy may be due to reduced tumour-cell content of the biopsy.

Failure of intensive combination therapy (cyclophosphamide, adriamycin, 5-fluorouracil) to control adenocarcinoma or large-cell anaplastic carcinoma of lung.

Eleven patients with advanced adenocarcinoma of lung and six patients with large cell anaplastic carcinoma of lung were treated with combination chemotherapy using cyclophosphamide 1 g/m2 i.v., adriamycin 30 mg/m2 and 5-FU 500 mg/m2 i.v. on days 1 and 8, of a 28 day cycle. In neither group did any patient achieve a complete remission; 1 patient achieved a partial response in each group, and the rest showed no evidence of response. The duration of survival of the responding patients in each group was not significantly longer than those of the non-responders. Toxicity and side effects were considerable in all patients. This study demonstrates that these tumour types are refractory to this form of intensive combination chemotherapy. A literature review suggests that other forms of combination chemotherapy are usually equally ineffective.