Arbitrary qubit transformations on tuneable Rashba rings

An exact solution is presented for the time-dependent wave function of an initial ground-state Kramers-doublet qubit that is driven around a quantum ring. We show that the initial qubit may be transformed to an arbitrary point on the Bloch sphere for an integral number of revolutions around the ring. Full coverage of the Bloch sphere is achieved by dividing the total rotation into segments, changing the rotation axis after each segment by an adiabatic shift in the Rashba spin-orbit interaction. Prospects and challenges for possible realizations are discussed for which rings based on InAs quantum wires are promising candidates

Carcinoma of the soft palate and the posterior oropharyngeal wall

Between 1966 and 1984, 14 patients with carcinoma of the soft palate and eight patients with a posterior oropharyngeal wall carcinoma were treated at the Netherlands Cancer Institute. In the soft palate group, the majority of patients (10) had small tumours T1-T2; the median patient delay was 1 month (range 0-5). Eleven patients were treated with radiotherapy and three with surgery, as single treatment modalities. Tumour control was achieved in 10 patients following initial treatment. Five-year results for tumour control and overall survival were 67% and 41%, respectively. In the posterior wall group all patients had advanced tumours (T3-T4), after a median patient delay of 4 months (range 0-6). Six patients were treated with radiotherapy, one with surgery only and one with a combination of these. Following the initial treatment, tumour control was achieved in half of the patients. Five-year tumour control was 50%, and overall survival at 5 years was 38%. In conclusion, the tumours in these two sub-sites of the oropharynx differ significantly in the extent of the primary tumour (P <0.01), posterior wall tumours being more advanced on admission, after a significantly longer history (P <0.01

Radiotherapy of tonsillar and base of the tongue carcinoma. Prediction of local control

119 patients with squamous cell carcinoma of the tonsillar region (68) and the base of the tongue (51), who received external radiotherapy with curative intent between 1966 and 1984, are analysed with respect to overall treatment results, local tumour control and prognostic factors. Radiation doses were equivalent to 60-70 Gy in 6-7 weeks, with a mean fraction dose of 2.4 Gy on the cobalt 60 equipment and 2 Gy on the linear accelerator. Significant differences were found between both oropharyngeal subsites. Three-year overall survival was 57% in tonsillar carcinoma and 38% in base of the tongue (P = 0.006); disease-specific survival was 70% and 47%, respectively (P = 0.005); and local control rates were 82% and 61% (P = 0.02). Late damage to normal tissues, like persistent dysphagia and osteomyelitis, were seen in 11% of patients. Patients with large tumours in the tongue based developed significantly more complications (P = 0.04). T-stage and tumour subsite predicted local control independently before start of the treatment (P = 0.02 in both cases). A significant nonlinear correlation between Normalised Total Dose (using an alpha/beta ratio of 15 Gy) and local control rate was found (P = 0.006), the middle range having the worst prognosis. The size of radiation field and overall treatment time did not correlate with local control in either site. Response at the end of radiotherapy and 6 weeks later have additional prognostic value for local control, irrespective of the initial stage or subsite (P = 0.004 and <0.001, respectively