The president joked that “we’re building ‘Iron Man,’” but Obama’s jest contained more than a kernel of truth: The exoskeleton, called the Tactical Assault Light Operator Suit (TALOS), does look vaguely like the fictional Tony Stark’s famous Iron Man suit.The first prototypes already are being built, and if all goes as planned, American soldiers may soon be much stronger and largely impervious to bullets.A little more than a year later and an ocean away, scientists with the United Kingdom’s National Health Service (NHS) announced that by 2017, they plan to begin giving human subjects synthetic or artificial blood.If the NHS moves ahead with its plans, it would be the first time people receive blood created in a lab.While the ultimate aim of the effort is to stem blood shortages, especially for rare blood types, the success of synthetic blood could lay the foundation for a blood substitute that could be engineered to carry more oxygen or better fight infections.Scientists are making tissue and blood in the laboratory.