No abstract

Biomineralization in crustaceans is a remarkably efficient process of ion transport and phase transformation in a spatial template. Here we show the use of this preorganized pathway with waste shrimp shell as both a phosphate source and template for the mineralization of UO2 2+ to uramphite. By using the physical structural and chemical reservoir of the biogenic platform, the only requirement was to develop a solution for ion supply. Hydroxylammonium acetate, an amphiprotic salt parallel to the amine and carboxylic acid motif pervasive in biomolecules, was prepared and used for the delivery of dissolved uranyl ions into the spatial constraints of the exoskeleton. Although biomediated phase transformations of exogenous metals is typically limited to living organisms, our results show that metabolically inactive shrimp shells are adaptive and responsive toward a nonessential ion. This suggests the nonliving exoskeleton may provide rapid bottom-up assembly routes to technologically important new inorganic crystalline materials.

Many policies attempt to help extremely poor households build sustainable sources of income. Although economic interventions have predominated historically1,2, psychosocial support has attracted substantial interest3–5, particularly for its potential cost-effectiveness. Recent evidence has shown that multi-faceted ‘graduation’ programmes can succeed in generating sustained changes6,7. Here we show that a multi-faceted intervention can open pathways out of extreme poverty by relaxing capital and psychosocial constraints. We conducted a four-arm randomized evaluation among extremely poor female beneficiaries already enrolled in a national cash transfer government programme in Niger. The three treatment arms included group savings promotion, coaching and entrepreneurship training, and then added either a lump-sum cash grant, psychosocial interventions, or both the cash grant and psychosocial interventions. All three arms generated positive effects on economic outcomes and psychosocial well-being, but there were notable differences in the pathways and the timing of effects. Overall, the arms with psychosocial interventions were the most cost-effective, highlighting the value of including well-designed psychosocial components in government-led multi-faceted interventions for the extreme poor.