Often , prepared packs are warm ; the heat opens up the pores of the skin , and helps the interaction of the clay with the body .
Prepared packs are often warm , the heat opens the pores of the skin and supports the interaction of the clay with the body .

Are these two sentences paraphrases of each other?
yes

It was originally developed by groups of Chinese and Russian scholars in the Soviet Union , and used by Chinese immigrants there until the majority left the country .
It was originally developed by groups of Chinese scholars in the Soviet Union and used by Chinese and Russian immigrants there until the majority of them left the country .

Are these two sentences paraphrases of each other?
no

Thiago is the father of current players Mazinho by Inter Milan and Rafinha of Bayern Munich .
Thiago is the father of current players Mazinho of Inter Milan and Rafinha of Bayern Munich .

Are these two sentences paraphrases of each other?
yes

On 19 October , Shire PLC ( SHPG ) Linear Technology ( LLTC ) replaced the index .
On 19 October , Linear Technology ( SHPG ) replaced the Shire PLC ( LLTC ) index .

Are these two sentences paraphrases of each other?
no