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    Impact of previous SWL on ureterorenoscopy outcomes and optimal timing for ureterorenoscopy after SWL failure in proximal ureteral stones
    (Springer Verlag, 2019) Irer B.; Sahin M.O.; Erbatu O.; Yildiz A.; Ongun S.; Cinar O.; Aegean Study Group of the Society of Urological Surgery
    Purpose: We aimed to evaluate the impact of previous unsuccessful shock wave lithotripsy (SWL) therapy on ureterorenoscopy (URS) outcomes in proximal ureteral stones and to define whether there is any optimal timing for safe URS after SWL. Methods: The patients who underwent URS for proximal ureteral stones between the years 2015 and 2018 in eight centers were included. Patients were divided into two groups according to previous SWL history; group 1 consisted of patients without SWL before URS for the stone [SWL (-)] and group 2 consisted of patients with a previous SWL for the stone [SWL (+)]. Demographics, operation outcomes and stone characteristics were compared between these two groups. Regarding the complication and success rates, optimal timing for URS after SWL for the stone was calculated with receiver operator characteristics curve analysis. Results: Totally 638 patients were included (group 1: 466 patients and group 2: 172 patients). The operation and hospitalization times, rate of ureteral stenting and complications were significantly higher in group 2. Stone free status was similar between the groups. Optimal timing for URS after SWL was calculated as 16.5 days (AUC = 0.657, p = 0.012) with a sensitivity of 68% and specificity of 72%, regarding the complication rates. Complication rates were significantly higher in patients who were operated before 16.5 days (27.7% vs 6.5%, p < 0.001). Conclusions: The optimal timing; 2–3 weeks delay of the URS procedure after unsuccessful SWL may decrease complication rates according to our results. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Physicochemical properties and availability of Tahar-Güzelöz (Nevşehir) diatomite
    (General Directorate of Mineral Research and Exploration (MTA), 2018) Yildiz A.; Gürel A.; Okutan D.
    In this study, utilization of Tahar-Güzelöz (Nevşehir) diatomites occurring within the late Miocene-Pliocene age vocanosedimentary units which formed due to volcanism and outcropping in Tahar and Güzelöz (Nevşehir) areas were investigated. In the study area, three stratigraphic sections were measured, one of which was measured in the Tahar area (TK), and the two others were measured in the Güzelöz area (GÜ1 and GÜ2). Various physicomechanical, chemical, mineralogical and analytical methods were used on the samples. Analyses results of the diatomites in the investigated area were determined as follow; amount of acid-insoluble matters; 74,20 - 84,20 %, amount of water-insoluble matters; 99,80 %, loss on ignition ratios (950 °C de); 8,18 - 22,82 %, whitenesses; 80,45 - 84,79 %, particle sizes; 0,7-209 µ, pore sizes; 1,448 e-03A – 5,888 e-04A, pore volumes; 1,148 e-02 – 8,515 e-02 cc/g, specific gravities; 2,33 – 2,49 gr/cm3 , total porosities; 57 –60 %, cumulative specific surface areas; 4,047 e+01 – 5,160 e+01 m2/g, pH; 5-7 (acit and neutral), filtration rates; 138 – 351 ml/dk, SiO2 contents; 38,16 – 67,77 %. It was determined that, the samples are not contain palinological material and these generally formed from long and large diatom genus and species. The evaluation of the analyses results showed that, none of the three location’s diatomites is suitable as construction material, carrier, mild abrasive and cleaner, isolution material. At the same time, determined that, the Tahar and Güzelöz–1 location’s diatomites can not be used as filler material. In addition, it was determined that, the subject diatomites can be used in the manufacture of silicate, and in percolator by the enrichment in terms SiO2 . Also, Güzelöz-2 location’s diatomites can be used as filler material in the rubber and paper industries. © 2018 General Directorate of Mineral Research and Exploration (MTA). All rights reserved.
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    Physicochemical properties and uses of Karacaören area (Nevşehir) diatomite
    (General Directorate of Mineral Research and Exploration (MTA), 2016) Yildiz A.; Gürel A.; Dursun Y.G.
    In this study, physicochemical properties and the area of use of diatomites that occur in association with Central Anatolian volcanism in the Karacaören region (Ürgüp country, Nevşehir) are investigated. In the investigated area two stratigraphic sections were measured, one is in Quaternary lake units (K1) and another section is in the lacustrine sediments of Bayramhacili member within Ürgüp formation of late Miocene-Pliocene age (K2). In order to specify physicochemical properties and the area of use of diatomites, various analyses were carried out at the Laboratories of General Directorate of Mineral Research and Exploration including loss on ignition (at 1050 °C), XRD, amount of acid and water-insoluble matter, thermal conductivity (in the range of 101; 150 °C and ± 10 °C), XRF, pH, total porosity, specific gravity, specific surface area, pore volume, pore size, whiteness, particle size and SEM analysis. The evaluation of the analyses results showed that the studied diatomites have a commercial value and can be used directly in percolator, as filler and structuring agents and in silicate manufacturing. In addition, once processed, they can also be used as mild abrasive and cleaner in production of isolation material.