objective: this study presents an efficient, cost-effective method to improve proliferation and colonization of spermatogonial stem cells (sscs) in vitro. methods: isolated sscs from neonate mice were cultured in dmem culture medium with 10% fetal bovine serum (fbs). in the first phase of the study, the temperature was controlled by low intensity pulsed ultrasound stimulation (lipus) of the pla...

Nitriding is a surface treatment technique used to introduce nitrogen into metallic materials to improve their surface hardness, mechanical properties, wear resistance and corrosion resistance. In this research, the effects of plasma nitriding parameters including frequency and duty cycle were investigated on samples with different grooves dimensions. Steel blocks prepared from DIN1.2344 hot wo...

the direct torque control (dtc) of interior permanent magnet synchronous motor (ipmsm) offers simple structure and fast torque response. the conventional switching table-based dtc (st-dtc) presents some disadvantages like high torque and flux ripple and also variable switching frequency. this paper investigates the improved st-dtc strategies to reduce both torque and flux ripple in dtc of ipmsm...

Novel frequency doubler circuits and dividers for clock signal generation are presented. In combination with two edge detectors and two duty cycle control buffers a low cost frequency doubler circuit is achieved as compared to Phase-Locked Loop (PLL) design. An input clock signal with an unpredictable duty cycle is inputted to a rising (or falling) edge detector. The edge detector converts the ...

BACKGROUND Duty cycle is the portion of time spent in compression relative to total time of the compression-decompression cycle. Guidelines recommend a 50% duty cycle based largely on animal investigation. We undertook a descriptive evaluation of duty cycle in human resuscitation, and whether duty cycle correlates with other CPR measures. METHODS We calculated the duty cycle, compression dept...

A simple odd number frequency divider with 50% duty cycle is presented. The odd number frequency divider consists of a general odd number counter and the proposed duty cycle trimming circuit. The duty cycle trimming circuit can output 50% duty cycle with only additional six transistors. A prototype divide-by-5 circuit with 50% duty cycle was implemented for a 500-Mb/s ∼ 5.6-Gb/s 1:10 CDR/DEMUX ...

BACKGROUND Sustained compression is recommended to maximize myocardial and cerebral blood flow during cardiopulmonary resuscitation (CPR) in adults and children. We compared myocardial and cerebral perfusion during CPR in three groups of 2-week-old anesthetized swine using compression rates and duty cycles (duration of compression/total cycle time) of 100 per minute, 60%; 100 per minute, 30%; a...

A new fuzzy maximum power point tracker (MPPT) for photovoltaic systems is proposed. Fuzzy controller input parameters dI dP , ) dI dP ( D and variation of duty cycle ( DC D ) are used to generate the optimal MPPT converter duty cycle, such that solar panel maximum power is generated under different operating conditions. A photovoltaic system including a solar panel, a fuzzy MPP tracker and...