RESUMO
In this work, a novel wire-shaped supercapacitor based on nylon yarn with a high specific capacitance and energy density was developed by designing an asymmetric configuration and integrating pseudocapacitive materials for both electrodes. The nylon/Ag/MnO2 yarn was prepared as a positive electrode by electrochemically depositing MnO2 on a silver-paste-coated nylon yarn. Additionally, PPy was prepared on nylon/Ag yarn by chemical polymerization firstly to enlarge the surface roughness of nylon/Ag, and then the PPy could be easily coated on the chemically polymerized nylon/Ag/PPy by electrochemical polymerization to obtain a nylon/Ag/PPy yarn-shaped negative electrode. The wire-shaped asymmetric supercapacitor (WASC) was fabricated by assembling the nylon/Ag/MnO2 electrode, nylon/Ag/PPy electrode and PAANa/Na2SO4 gel electrolyte. This WASC showed a wide potential window of 1.6 V and a high energy density varying from 13.9 to 4.2 µWh cm-2 with the corresponding power density changing from 290 to 2902 µW cm-2. Meanwhile, because of the high flexibility of the nylon substrate and superior adhesion of active materials, the WASC showed a good electrochemical performance stability under different bending conditions, suggesting its good flexibility. The promising performance of this novel WASC is of great potential for wearable/portable devices in the future.
RESUMO
OBJECTIVE: The true incidence of ovarian tumors in children is unknown. Few studies beyond case reports and case series have been published concerning pediatric ovarian tumors. Herein we review a large number of ovarian tumor cases. METHODS: The charts of 203 patients who presented with adnexal masses were reviewed. RESULTS: The patient's ranged in age from 2 to 18 years (mean = 15.6 years), with 30 being premenarchal (14.8%). The incidence of ovarian tumor increases with age, especially in patients older than 14 years. The main complaint was abdominal pain or abdominal distension in 117 patients (57.7%). A high AFP level in a pre-pubic girl with an adnexal mass is indicative of a malignant ovarian tumor. The 214 adnexal masses (11 patients had bilateral cysts) consisted of benign tumorous oophoropathy (107 masses, 50.0%), borderline and malignant tumors (29 masses, 13.6%), and nontumorous oophoropathy (78 masses, 36.5%). Of the 136 neoplasia, germ cell tumors accounted for 71.5%. Surgical intervention was performed in 98.5% of cases. There were statistically decreased blood loss, surgery duration and days of hospitalization with the laparoscopic procedure when compared with open surgery. CONCLUSIONS: Abdominal pain is the most common complaint in young patients with adnexal masses. AFP is the most useful diagnostic biomarker of ovarian tumors in young females. Laparoscopic resection of ovarian cysts is an alternative operation approach.