In this paper, an LLC resonant dc-dc converter is proposed for high voltage applications. Full bridge inverter, LLC resonant tanks, high voltage transformer and full bridge rectifier are comprised in the proposed converter circuit. In operating frequency of proposing converter, output voltage regulation is achieved by narrow varying. The energy trapped in leakage inductance of the transformer and to achieve ZVS feature, LLC resonant circuit is utilized to retrieve. It also increases conversion efficiency. A high voltage transformer is used to step up AC voltage which is then refined by the rectifier. With the equivalent circuit derived by first harmonic approximation (FHA method, input-output response and DC characteristics in frequency domain are obtained. The theoretical equations of the circuit operations are studied in detail to infer. Finally, a design example is implemented out to establish the feasibility of the proposed LLC resonant converter. The simulation results on the essential switching and circuit operation are presented. The robustness of this study is verified by the simulation results of the proposed converter with 300V input and 3.5kV/0.35A output.

Introduction: Frequency of lower urinary tract symptoms (LUTS) in young age women is not well studied. It is said to be common among female elderly and multiparous population. The aim of this study is to obtain the prevalence of LUTS among nulliparous students in relation to their personal hygiene. Materials and methods: This is a prospective cross-sectional study conducted among  200 nulliparous medical and nursing students aged between 18-28 years using standardized questionnaires. Urine samples were also collected from students to detect urinary tract infections. Results: The complete data sets of 146 students were analyzed. All of them were nulliparous, single and not sexually active. The prevalence of LUTS was 52.7% consist of over-active bladder, urinary incontinence (UI) and voiding difficulty respectively (51.3%, 34.9% and 45.2%). The most common type of UI was stress urinary incontinence which was 21.9% followed by 11.6% of urgency incontinence. Conclusion: The prevalence of LUTS among young age population is high at 52.7%. Public awareness regarding LUTS and availability of treatment is needed.