TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Structure: The structure (S1) is spherical. The structure (S1) further comprises substrate. Preferred Components: The metal powder comprises at least one of aluminum, copper, stainless steel, titanium, iron, chromium, manganese, tin, and zinc. The metal powder comprises at least two different metal species. The metal powder comprises copper and at least one of aluminum, titanium, and zinc. The metal powder comprises particles having an average major dimension of less than 10 microns. The porous metallic matrix comprises at lest one of aluminum, copper, stainless steel, nickel, tin, titanium, zinc, iron, chromium, and manganese. The porous metallic matrix comprises at least two of aluminum, copper, stainless steel, nickel, tin, titanium, and zinc. The porous metallic matrix comprises copper and at least one of aluminum, stainless steel, titanium, and zinc. The porous metallic matrix comprises homogenous distribution of first metal and second metal.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The method (M1) further involves crosslinking the collagen nanofibrils in the shaped body prior to removing the collagen nanofibrils. The crosslinking comprises dehydrothermal crosslinking. The method (M1) further involves cooling the porous metallic structure following the removal of the collagen nanofibrils. The carrier comprises aqueous solution having pH lower than 7. The collagen nanofibrils are produced by providing a solution of raw corium, where the corium contains several bundled collagen fibers; milling the solution of raw corium; and optionally sonicating the milled solution of raw corium; and recovering the collagen nanofibrils from the solution. The ratio of the first metal species to the second metal species in the metal powder is 1:1-1:9 by weight. The ratio of metal powder to collagen nanofibrils in the blend is 1:1-40:1 (preferably 1:1, 5:1, 10:1, or 20:1) by weight. The shaped body is formed by applying the blend onto a substrate. The shaped body is formed by freezing the blend. The amount of carrier is reduced in shaped body by freeze-drying. The removal of a major proportion of the collagen nanofibrils comprises flash heating the shaped body, followed by sintering the shaped body. The flash heating is performed at 300-1400 (preferably 400, 600, 800 or 1200) degrees C. The duration of the flash heating is 1-3 hours. The sintering is performed at 400-1400 (preferably 600 or 800 or 900 or 1000, or 1100 or 1200) degrees C. The duration of the sintering is 1-6 hours. The heating is effective to produce an average pore size of 1-100 microns in the porous metallic structure. Preferred Components: The corium is bovine, and/or porcine. The collagen nanofibrils have an average diameter of 10-250 nm. EXAMPLE - No suitable example given.