Nitrogen doped porous carbon nanopolyhedra (N-PCNPs) were prepared from direct carbonization of ZIF-8 nanopolyhedra. The N-PCNPs showed uniform morphology, narrow pore-size distribution centered at 3.7 nm, high surface area (2221 m 2 g À1 ) and good electrochemical properties and were used to modify a glassy carbon electrode to electrochemically detect ascorbic acid (AA), dopamine (DA) and uric acid (UA). Compared with the bare GC electrode and reduced graphene oxide modified glassy carbon (rGO/GC) electrode, the N-PCNPs modified GC electrode (N-PCNPs/GC) was found to perform better toward electrocatalytic oxidation of AA, DA and UA. For simultaneous sensing of three analytes, three well-separated voltammetry peaks were obtained using the N-PCNPs/GC electrode in differential pulse voltammetry measurements, and the corresponding peak separations between AA and DA, DA and UA were 228 mV, 124 mV respectively. The linear response ranges for the determination of AA, DA and UA were 80-2000 mM, 0.5-30 mM and 4-50 mM, respectively, and the detection limits (S/N ¼ 3) were 740 nM, 11 nM and 21 nM, respectively. Furthermore, the N-PCNPs/GC electrode showed good reproducibility and stability. The attractive features of N-PCNPs provided potential applications in the simultaneous determination of UA, AA and DA.

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Intergroup conflict contributes to human discrimination and violence, but persists because individuals make costly contributions to their group’s fighting capacity. Yet how group members effectively coordinate their contributions during intergroup conflict remains poorly understood. Here we examine the role of oxytocin for (the coordination of) contributions to group attack or defense in a multi-round, real-time feedback economic contest. In a double-blind placebo-controlled study with N=480 males in an Intergroup Attacker-Defender contest game, we found that oxytocin reduced contributions to attack and over time increased attacker’s within-group coordination of contributions. However, rather than becoming peaceful, attackers given oxytocin better tracked their rival’s historical defense and coordinated their contributions into well-timed and hence more profitable attacks. Our results reveal coordination of contributions as a critical component of successful attacks and subscribe to the possibility that oxytocin enables individuals to contribute to in-group efficiency and prosperity even when doing so implies outsiders are excluded or harmed.Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).