Question
Can you use a knife to cut bread or apply butter to bread during Shabbat? Or would the cutting of bread be considered part of the preparation for Shabbat and done before its arrival?

Question
If somebody gets plastic surgery, do the implants ever count as Chatzitzah. For example for a woman who gets breast implants, will that be a Chatzitzah for the mikveh? Sources for the Halacha/responsa regardinf this question please