No abstract

Extracorporeal shockwave lithotripsy (SWL) has remained the preferred method of treatment of urinary stones since its introduction in 1980. Although SWL is classified as a potential first-line treatment for renal stones smaller than 2 cm and its overall success rate is higher than 85% for stone clearance, not all renal calculi are successfully fragmented after SWL. Among the urinary stones, calcium oxalate monohydrate (COM) stone is one of the hardest stones to fragment. Several factors interfering with stone fragility are known to exist. In addition to technical properties for SWL to increase the quality and rate of stone disintegration, the composition of stones such as trace element levels may also interfere with the efficacy of SWL. Therefore, in the present study, we aimed to elucidate the correlation, if it exists, between fragmentation of renal stones and their trace element (Cu, Zn, Mg, Fe, Pb, Mn, Cr) concentrations. For this purpose, the patients admitted to our department who were identified with urinary stones (740 patients) and underwent SWL sessions were evaluated prospectively. Patients having 5-20 mm of solitary COM stone in the renal pelvis were included in this study. The trace element concentrations of renal stones that were successfully fragmented with SWL (SWL-S) were compared with those that were unsuccessfully fragmented after three SWL sessions (SWL-US) and removed surgically. Our measurements showed that the concentrations of Cu, Fe, Pb, and Cr were similar in both groups; by contrast, the concentration of Zn, Mg and Mn was significantly lower in SWL-US renal stones. The present results suggest that low concentrations of Zn, Mg and Mn in COM stones appear to make them resistant to SWL fragmentation and may offer a critical distinction for the choice of a treatment program.

Özet -Bu çalışmanın iki amacı vardır ve iki bölümden oluşmaktadır. Çalışmanın birinci bölümünde gerçek boyutlarından küçültülerek Güneş-Dünya-Ay modeli geliştirilmiş, ikinci bölümünde ise bu modelin öğretmen adaylarının astronomi başarıları üzerine etkisi araştırılmıştır. Öğretmen adaylarının astronomi başarılarındaki değişimi incelemek amacıyla Astronomi Başarı Testi geliştirilmiş, 60 öğretmen adayına ön test ve son test olarak uygulanmıştır. Öğrencilerin yarısına ilgili konular, standart öğretim ile anlatılırken, kalan yarısına ise geliştirilen model kullanılarak anlatılmıştır. Araştırmanın sonucunda modelle öğretimin öğrenme ve anlama bakımından önemli etkilere yol açtığı görülmüştür.

No abstract

Ionospheric critical frequency (foF2) is an important ionospheric parameter in telecommunication. Ionospheric processes are highly nonlinear and time varying. Thus, mathematical modeling based on physical principles is extremely difficult if not impossible. The authors forecast foF2 values by using neural networks and, in parallel, they calculate foF2 values based on the IRI model. The foF2 values were forecast 1 h in advance by using the Middle East Technical University Neural Network model (METU‐NN) and the work was reported previously. Since then, the METU‐NN has been improved. In this paper, 1 h in advance forecast foF2 values and the calculated foF2 values have been compared with the observed values considering the Slough (51.5°N, 0.6°W), Uppsala (59.8°N, 17.6°E), and Rome (41.8°N, 12.5°E) station foF2 data. The authors have considered the models alternative to each other. The performance results of the models are promising. The METU‐NN foF2 forecast errors are smaller than the calculated foF2 errors. The models may be used in parallel employing the METU‐NN as the primary source for the foF2 forecasting.