The mother-and-daughter duo tottered back onto the cobbles like a pair of evil twins, with sarcasm and surliness dripping from every one of their pretty little pores.
Each filter is made up of tiny micro tubes with pores hundreds of times smaller than the diameter of a human hair.
I have met staff whose joy in their work seeped out of their very pores and I have listened to a thousand complaints.
These pores remove deadly bacteria and allow only clean water to pass through for drinking.
They also added blood, which has the effect of making the stuff more frost-resistant by creating extra pores.
Nicholas Kotov of the University of Michigan in Ann Arbor and his colleagues have therefore been trying to grow human marrow artificially.When they started their research, Dr Kotov and his team knew that the stem cells from which marrow is derived grow naturally in specialised pores within bone.
Rigs are migrating from gassy places like the Haynesville Shale, in Louisiana, to spots where oil is trapped in tiny rock pores, such as the Permian Basin and Eagle Ford Shale in Texas, the Bakken formation of North Dakota and the Mississippian Lime, which sits astride the border between Oklahoma and Kansas.
These pores are between 100 and 200 nanometres in diameter perfect for trapping the rods and thus marking the tumour.
Timken, another steelmaker, is spending $200m on its mill in Canton, Ohio.The main reason for this flurry of investment lies a few thousand feet below the ground: the Marcellus shale, a geological formation containing huge reserves of natural gas trapped in tiny pores in the rock.
These pores are lined by a mixture of connective-tissue cells, bone cells and fat cells, which collaborate to nurture the stem cells.
Third, pores punched in this way are straight, rather than being convoluted channels as is the case in a polymer membrane.
