The road network suffered from inadequate load capacity, poor surfacing and deficient roadside servicing. Correcting low or deficient zinc levels can help elevate serum uric acid. "Candida" species cause infections in individuals with deficient immune systems. There were a number of bridges deemed structurally deficient. Individuals who are deficient in leptin fail to initiate puberty. Plants and animals grown in iodine deficient soils are correspondingly deficient. This will replace an existing pedestrian bridge, which has been designated as "structurally deficient". Further study conducted in neuronal cultures derived from presenilin-1 deficient mouse embryos. It is also used to treat kidney stones caused by deficient activity of adenine phosphoribosyltransferase. This is consistent with an interpretation of PTSD as a syndrome of deficient extinction ability. Triad members may experience themselves as incomplete, deficient, or unfinished. Some species of frog have adaptations that allow them to survive in oxygen deficient water. The 5-position is less electron deficient and substituents there are quite stable. Like primaquine, tafenoquine causes hemolysis in people who are G6PD deficient. A 2007 survey concluded that low and deficient niacin status was common in Angola.