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    A new capacitive rotary encoder based on analog synchronous demodulation
    (Springer, 2018) Karali, M.; Karasahin, A. T.; Keles, O.; Kocak, M.; Erismis, M. A.
    Rotary encoders, which are mainly used to feedback the angle of the robot arm to the robot controller system, are widely used in industrial and robotic applications. While optical and magnetic rotary encoders are dominant in the market, capacitive rotary encoders are also gaining interest for their simple design, ability to miniaturize and being absolute encoders insensitive to magnetic field variations. In this study, a new economical capacitive rotary encoder based on analog synchronous demodulation is developed. Analog synchronous demodulation technique is used for the first time in the literature as far as known to the authors for capacitive rotary encoders. It is chosen as it is quite robust, simple and economical. A compact mechanical body is developed by 3D printing. After packaging, the sensor is fixed to a motor for testing. The developed encoder shows 2880 pulse/rotation resolution and repeatable output under different temperature environments.
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    Risk for Malignant and Borderline Ovarian Neoplasms Following Basic Preoperative Evaluation by Ultrasonography, Ca125 Level and Age
    (Asian Pacific Organization Cancer Prevention, 2014) Karadag, Burak; Kocak, M.; Kayikcioglu, F.; Ercan, F.; Dilbaz, B.; Kose, M. F.; Haberal, A.
    Objective: To verify the basic preoperative evaluation in the discrimination between benign and malignant adnexal masses in our clinical practice. Materials and Methods: Data were collected on the records of 636 women with adnexal masses who had undergone surgery either by open or endoscopic approaches. Those with obvious signs of malignancy, any history of cancer, emergency surgeries without basic evaluation were excluded. The preoperative features by age, ultrasound and serum Ca125 level were compared with final histopathological diagnosis at the four departments of the institution. These are the general gynecology (Group 1:exploratory laparotomy), the gynecologic endoscopy (Group 2: laparoscopy and adnexectomy), the gynecological oncology (Group 3:staging laparotomy) and the gynecologic endocrinology and infertility (Group 4: laparoscopy and cystectomy). Results: There were simple and complex cyst rates of 22.3% and 77.2%, respectively. There were 86.3% benign, 4.1% (n:20) borderline ovarian tumor (BOT) and 6.4% (n:48) malignant lesions. There were 3 BOT and 9 ovarian cancers in Group 1 and one BOT and two ovarian cancer in the Group 2. During the surgery, 15 BOT (75%) and 37 ovarian cancer (77%) were detected in the Group 3, only one BOT was encountered in the Group 4. The risk of rate of unsuspected borderline or focally invasive ovarian cancer significantly increased by age, size, complex morphology and Ca125 (95% CI, OR=2.72, OR=6.60, OR=6.66 and OR=4.69, respectively). Conclusions: Basic preoperative evaluation by comprehensive ultrasound imaging combined with age and Ca125 level has proved highly accurate for prediction of unexpected malignancies. Neither novel markers nor new imaging techniques provide better information that allow clinicians to assess the feasibility of the planned surgery; consequently, the risk of inadvertent cyst rupture during laparoscopy may be significantly decreased in selected cases.