The Friday Five covers five stories in health research over the previous week that you may have missed. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend. Covered in this week's Friday Five:- A new blood test for cancer - Patch of bacteria uses your sweat to power electronic devices- Researchers revive organs of dead pigs- Phone apps detect cancer-causing chemicals in foods- Stem cells generate "synthetic placentas" in micePlus, an honorable mention for early research involving vitamin K and Alzheimer's