[en] The general binary breakage problem with power-law breakage functions and two families of symmetric and asymmetric breakage kernels is studied in this work. A useful transformation leads to an equation that predicts self-similar solutions in its asymptotic limit and offers explicit knowledge of the mean size and particle density at each point in dimensionless time. A novel moving boundary algorithm in the transformed coordinate system is developed, allowing the accurate prediction of the full transient behaviour of the system from the initial condition up to the point where self-similarity is achieved, and beyond if necessary. The numerical algorithm is very rapid and its results are in excellent agreement with known analytical solutions. In the case of the symmetric breakage kernels only unimodal, self-similar number density functions are obtained asymptotically for all parameter values and independent of the initial conditions, while in the case of asymmetric breakage kernels, bimodality appears for high degrees of asymmetry and sharp breakage functions. For symmetric and discrete breakage kernels, self-similarity is not achieved. The solution exhibits sustained oscillations with amplitude that depends on the initial condition and the sharpness of the breakage mechanism, while the period is always fixed and equal to ln 2 with respect to dimensionless time

[en] Full text of publication follows. Aim: to retrospectively evaluate any factors that may limit the success rate of radioiodine therapy (RIT) in Graves' disease patients. Methods: 80 Graves' disease patients submitted for RIT in our department in a two years' period (2010-2011) were enrolled in the study. A fixed dose of 12 mCi (444 MBq) of ¹³¹I was administered to all patients after antithyroid drug administration, in order to achieve normal FT3 serum values. Thyroid function outcome were assessed 10-12 months after RIT. Patient's sex, age, evidence of ophthalmopathy, ultrasound measurement of the thyroid volume and ^99mTc thyroid uptake % prior to RIT were considered as potential interference factors for success. Multiple logistic regression analysis was performed. Results: after RIT, 9 patients (11%) became euthyroid, 48 patients (61%) became hypothyroid and 23 (28%) remained hyperthyroid. No statistically significant association between treatment outcome and sex (p = 0.56), age (p=0.61) and ophthalmopathy (p = 0.72) was found. On the contrary, ^99mTc thyroid uptake % and thyroid volume were associated with success rate (thyroid uptake<14%, p<0.001, odds ratio 3.9 and thyroid volume <58 ml, p < 0.001, odds ratio 7.9). Conclusions: A radioiodine fixed dose of 12 mCi (444 MBq) for treatment of Graves' disease seems to be a practical and effective approach. However, this administration is not recommended for patients with large goiters and a high pre-RIT thyroid uptake, due to high failure rates observed in patients with thyroid volume more than 58 ml and thyroid uptake higher than 14%. (authors)

[en] Full text of publication follows. Background: Treatment of extensive diffuse pigmented villonodular synovitis (PVNS) of knee joint by isolated surgical resection is usually suboptimal, with high rates of local recurrence. Adjuvant treatment with intra-articular injection of yttrium-90 is supposed to provide better results. Aim: The aim of this study was to evaluate the efficacy of a combined treatment with radio synovectomy (RS) and surgical synovectomy (SS). Methods: the final effect of 21 RS performed in all 16 patients with PVNS presented in 2 years in our department was assessed. Adjuvant post-operative therapy using intra-articular injection of 5 mCi ⁹⁰Y was performed within 2-3 months after SS. 5 out of 16 patients had to be treated twice, due to a relapse of symptoms 4-6 months after the first treatment. Treatment efficacy was evaluated 8-12 months after the initial RS by a questionnaire reporting the relief of limiting the daily activities knee pain as a percentage of the pre-therapeutic joint discomfort using a visual analog scale (VAS). Relative uptake of Tc^99m-diphosphonate in the knee joint involved on the blood pool was also taken into consideration. Results: the overall response rate for all knee treatments was 81%. Results in double treated joints were significantly worse than in single treated ones. A significant improvement in blood pool bone scintigraphic signs of inflammation was noticed. On the other hand, there was no influence on late diphosphonate uptake. Conclusion: A combination of surgical synovectomy with adjuvant post-operative radio-synovectomy is highly efficacious in treating clinical symptoms of pigmented villonodular synovitis, with excellent results regarding the incidence of local recurrence and functional outcome. (authors)

[en] Since February 2016, the equatorial quasi-biennial oscillation (QBO) in zonal wind of the lower stratosphere exhibited anomalous behavior. In more detail, it broke down from its typical pattern and the eastward stratospheric winds unexpectedly reversed to a westward direction. We herewith attempt to detect whether this unprecedented event could be considered as a result of plausible long-range correlations in the QBO temporal evolution. The analyses performed using all the available QBO data sets showed that such an interpretation could not be inferred, because the temporal evolution of the equatorial zonal wind in the lower stratosphere does not exhibit power-law behavior. Further, the natural time analysis of the QBO data indicates precursory behavior before the maximization of the zonal wind velocity and that the recent strong El Niño event might be related with the aforementioned unprecedented behavior.