No abstract

No abstract

A new source of factitial dermatitis in adolescents is the "salt and ice challenge." This "challenge" causes frostbite on the child's body, resulting in epidermal necrosis with occasional bulla. The following is the case of a 12-year-old girl who underwent the "salt and ice challenge."

No abstract

On the other hand, we can get a variable DC voltage from a fixed DC source by using DC-DC converter. There are so many types of dc-dc converters available, Buck converter-to get the reduced output voltage. Boost converter-to get the output voltage more than input. Buck-Boost-to do both the operations buck and boost. Normally, buck-boost converter consists of single switch to do both the operations buck and boost according to MATLAB simulation model of Buck Boost DC-DC converter, according to the duty cycle of the gate pulse. Single switch buck-boost converter produces an inverting output with respect to input. This is a disadvantage of this converter. To get a non-inverting output voltage the converter is designed with two switches one for buck operation and another one for boost operation. The two mode control is achieved by implementing the input feed forward method. According to the input voltage level, buck or boost switch is selected.[2], [3] There are two active switches in the TSBB converter, which provides the possibility of obtaining various control methods for this converter. If Q1 and Q2 (switches) are switched ON and OFF simultaneously, the TSBB converter behaves the same as the single switch buck-boost converter. This control method is called one mode control scheme.[12] Q1 and Q2 can also be controlled in other manners. For example, when the input voltage is higher than the output voltage, Q2 is always kept OFF, and Q1 is controlled to regulate the output voltage, and as a result, the TSBB converter is equivalent to a buck converter, and is said to operate in buck mode. On the other hand, when the input voltage is lower than the output voltage, Q1 is always kept ON, and Q2 is controlled to regulate the output voltage, and in this case, the TSBB converter is equivalent to a boost converter, and is said to operate in boost mode. Such control method is called two-mode control scheme. [13]