Photoelectrochemical water splitting directly converts solar energy to chemical energy stored in hydrogen, a high energy density fuel. Although water splitting using semiconductor photoelectrodes has been studied for more than 40 years, it has only recently been demonstrated using dye-sensitized electrodes. The quantum yield for water splitting in these dye-based systems has, so far, been very low because the charge recombination reaction is faster than the catalytic four-electron oxidation of water to oxygen. We show here that the quantum yield is more than doubled by incorporating an electron transfer mediator that is mimetic of the tyrosine-histidine mediator in Photosystem II. The mediator molecule is covalently bound to the water oxidation catalyst, a colloidal iridium oxide particle, and is coadsorbed onto a porous titanium dioxide electrode with a Ruthenium polypyridyl sensitizer. As in the natural photosynthetic system, this molecule mediates electron transfer between a relatively slow metal oxide catalyst that oxidizes water on the millisecond timescale and a dye molecule that is oxidized in a fast light-induced electron transfer reaction. The presence of the mediator molecule in the system results in photoelectrochemical water splitting with an internal quantum efficiency of approximately 2.3% using blue light.artificial photosynthesis | photoelectrochemistry T he design of biomimetic systems for artificial photosynthesis is of fundamental interest in the study of light-driven electron and proton transfer reactions. It also represents a potential route to the efficient conversion of solar energy to energy stored in fuel. System modeling has shown that it should be possible, using complementary dye molecules that absorb in the infrared and the visible, to construct artificial Z-schemes that split water with over 10% energy conversion efficiency (1, 2). It is simpler in many ways to design small molecules with the proper photoredox properties than it is to find a set of semiconductors that can be coupled for visible light water splitting. Nevertheless, the molecular approach has so far lagged behind the semiconductor-based approach where high efficiencies have been realized with expensive materials (3-7).A ubiquitous problem in molecular artificial photosynthesis is back electron transfer, which rapidly thermalizes the energy stored by light-induced charge separation in donor-acceptor pairs. Recently, our group and several others have studied this problem in dye-sensitized solar cells where a molecular dye and a porous TiO 2 electrode act as the donor-acceptor dyad (8-13). The dye is covalently coupled to a colloidal or molecular water oxidation catalyst. Fast back electron transfer, relative to the rate of water oxidation, results in low quantum yields for water splitting in these systems.It is well known that charge-separation lifetimes in molecular donor-acceptor systems can be increased dramatically by adding secondary electron donors or acceptors to form triads, tetrads, and more complex supermolecu...

Graphical Abstract Highlights d Hi-C analysis of meiotic chromatin architecture during spermatogenesis d TADs and compartments A and B dissolve and then reappear during spermatogenesis d Pachytene chromatin has highly refined transcriptioncorrelated compartments d Inactive X chromosome during MSCI shows unique chromatin architecture

Summary Gene-editing technologies have made it feasible to create nonhuman primate models for human genetic disorders. Here, we report detailed genotypes and phenotypes of TALEN-edited MECP2 mutant cynomolgus monkeys serving as a model for a neurodevelopmental disorder, Rett syndrome (RTT), which is caused by loss-of-function mutations in the human MECP2 gene. Male mutant monkeys were embryonic lethal, reiterating that RTT is a disease of females. Through a battery of behavioral analyses, including primate-unique eye-tracking tests, in combination with brain imaging via MRI, we found a series of physiological, behavioral, and structural abnormalities resembling clinical manifestations of RTT. Moreover, blood transcriptome profiling revealed that mutant monkeys resembled RTT patients in immune gene dysregulation. Taken together, the stark similarity in phenotype and/or endophenotype between monkeys and patients suggested that gene-edited RTT founder monkeys would be of value for disease mechanistic studies as well as development of potential therapeutic interventions for RTT.

Maternal separation (MS), which can lead to hypothalamic pituitary adrenal axis dysfunction and behavioral abnormalities in rhesus monkeys, is frequently used to model early adversity. Whether this deleterious effect on monkeys is reversible by later experience is unknown. In this study, we assessed the basal hair cortisol in rhesus monkeys after 1.5 and 3 y of normal social life following an early separation. These results showed that peer-reared monkeys had significantly lower basal hair cortisol levels than the mother-reared monkeys at both years examined. The plasma cortisol was assessed in the monkeys after 1.5 y of normal social life, and the results indicated that the peak in the peer-reared cortisol response to acute stressors was substantially delayed. In addition, after 3 y of normal social life, abnormal behavioral patterns were identified in the peer-reared monkeys. They showed decreases in locomotion and initiated sitting together, as well as increases in stereotypical behaviors compared with the mother-reared monkeys. These results demonstrate that the deleterious effects of MS on rhesus monkeys cannot be compensated by a later normal social life, suggesting that the effects of MS are long-lasting and that the maternal-separated rhesus monkeys are a good animal model to study early adversity and to investigate the development of psychiatric disorders induced by exposure to early adversity.

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harvested and converted into heat for steam generation. [3] Because the existing ions, organics, and bacteria can be separated in the cost-effective and environmentally friendly process, solar energy-driven water evaporation is considered as a highly promising technology to purify water. [3b,4] Conventional water steam generation systems require many optical concentrators to achieve sufficiently high temperatures for heating water, low efficiency and high investment are the shortcomings. [3b] In this regard, recent studies focused on the localized heating of interfacial water based on photothermal materials with effective light absorption and light-to-heat conversion capabilities. [5] Nanoparticles such as gold, [6] titanium sesquioxide, [7] and alumina [8] were proposed for steam generation and water purification, but the low chemical stability, high cost, and low yield limit their large-scale applications. Carbon-based materials including graphene, carbon black, and carbon nanotubes have promising applications owing to their broadband light absorption, high stability, and low cost, [9] which are the most important prerequisites to ensure high solar energy conversion and practical application in water purification.Rational structural design for solar energy-driven water steam generation devices is significant to achieve high water evaporation efficiency and potential large-scale application. In the concept of heat localization, [10] the light-absorbing materials are integrated into the floating and thermally insulating substrates, which can effectively reduce the heat loss to the bulk water and enhance the water evaporation efficiency. Chen and co-workers developed a floating double-layer structure composed of exfoliated graphite and porous carbon foam with a water steam generation efficiency as high as 85% under 10 kW m −2 irradiation. [10a] A variety of solar energy-driven water evaporation devices with a bilayer structure, such as carbonized mushroom/polystyrene foam, [11] reduced graphene oxide/ bacterial nanocellulose biofoam, [12] graphene aerogel/polystyrene foam, [13] and carbon nanotube-coated wood, [14] were reported for high-efficiency water steam generation. However, these designed devices require precise and complicated fabrication processes, which limit their practicability and large-scale applications.Efficient utilization of abundant solar energy for clean water generation is considered a sustainable and environment friendly approach to mitigate the global water crisis. For this purpose, this study reports a flexible fire-resistant photothermal paper by combining carbon nanotubes (CNTs) and fire-resistant inorganic paper based on ultralong hydroxyapatite nanowires (HNs) for efficient solar energy-driven water steam generation and water purification. Benefiting from the structural characteristics of the HN/CNT photothermal paper, the black CNT surface layer exhibits a high light absorbability and photothermal conversion capability, the HN-based inorganic paper acts as a thermal insulator wit...

Soft carbon, which possesses the advantages of low cost and considerable potassium storage capacity, has been widely studied as an anode in K-ion batteries (KIBs). Herein, we constructed a novel polycrystalline semi-hollow microrods-structured soft carbon as an anode in KIBs, which exhibited both high capacity and excellent cycling stability.

Heteroatom-doped carbons represent a unique class of low-cost, effective catalysts for the electroreduction of oxygen, with a performance that may rival that of commercial Pt/C catalysts. In the present study, Fe and N codoped porous carbon nanotubules were prepared by controlled pyrolysis of tellurium nanowire-supported melamine formaldehyde polymer core–sheath nanofibers at elevated temperatures. Electron microscopic studies showed the formation of hollow carbon nanotubules with the outer diameter of 35–40 nm, inner diameter of 5–10 nm, and length of several hundred nanometers. Elemental mapping and spectroscopic measurements confirmed the doping of the carbon nanotubules with N and Fe including the formation of FeN4 moieties. Electrochemical studies showed that the resulting Fe,N-codoped carbons exhibited much enhanced electrocatalytic activity toward oxygen reduction in alkaline media as compared to the counterparts doped with nitrogen alone and prepared in a similar fashion, and the one prepared at 800 °C stood out as the best among the series, with an activity even better than that of commercial Pt/C. Such a remarkable performance was ascribed to the FeN4 moieties that facilitated the binding of oxygen species. This is further supported by results from DFT calculations, where relevant atomistic models were built based on experimental results and reaction free energies on various possible active sites were computed by first-principles calculations. The computational results suggested that for N-doped carbons, the active sites were the carbon atoms adjacent to nitrogen dopants, while for Fe,N-codoped carbon, the FeN4 moieties were most likely responsible for the much enhanced electrocatalytic activity, in excellent agreement with experimental results. Significantly, from the electronic structure studies, it was found that the high density of states close to the Fermi level and high spin density played a critical role in determining the electrocatalytic activity.