A solar wind-derived water reservoir on the Moon hosted by impact glass beads

The past two decades of lunar exploration have seen the detection of substantial quantities of water on the Moon’s surface. It has been proposed that a hydrated layer exists at depth in lunar soils, buffering a water cycle on the Moon globally. However, a reservoir has yet to be identified for this hydrated layer. Here we report the abundance, hydrogen isotope composition and core-to-rim variations of water measured in impact glass beads extracted from lunar soils returned by the Chang’e-5 mission. The impact glass beads preserve hydration signatures and display water abundance profiles consistent with the inward diffusion of solar wind-derived water. Diffusion modelling estimates diffusion timescales of less than 15 years at a temperature of 360 K. Such short diffusion timescales suggest an efficient water recharge mechanism that could sustain the lunar surface water cycle. We estimate that the amount of water hosted by impact glass beads in lunar soils may reach up to 2.7 × 1014 kg. Our direct measurements of this surface reservoir of lunar water show that impact glass beads can store substantial quantities of solar wind-derived water on the Moon and suggest that impact glass may be water reservoirs on other airless bodies

Synthesis and optical-electronic properties of a novel star-shaped benzodithiophene molecule

Benzodithiophene (BDT)-based star-shaped molecule (12TBDT) was synthesized by Stille coupling reactions. The star-shaped molecule shows high decomposition temperature (447 °C), low-lying HOMO level (-5.52 eV), and wide UVvis absorption between 300 and 530nm (Eg= 2.36 eV). DFT results show that the electron density of the HOMO and LUMO are localized on the thiophene and BDT groups. To the best of our knowledge, this is one of the earliest reports on star-shaped benzodithiophene molecules.</p

Improved open-circuit voltage of benzodithiophene based polymer solar cells using bulky terthiophene side group

Terthiophene, including one α-α and one branching α-β connection of the thiophene units, is introduced as benzodithiophene (BDT) side chain to build a novel two-dimensional (2D) conjugated BDT block. By copolymerizing this BDT block with three electron acceptors (DTTz (bis(thiophene-2-yl)-tetrazine), DPP (diketopyrrolopyrrole), DTffBT (4,7-bis(4-hexylthienyl)-5,6-difluoro-2,1,3-benzothiadiazole)) and one electron donor (TTT (2,5-Di(2-thienyl)thiophene)), four terthiophene side-chained benzodithiophene based copolymers were synthesized. Due to the difference in electron affinity among DTTz, DPP, DTffBT and TTT, these four polymers show different UV-vis absorption spectra and optical band gaps (1.3-2.0 eV), while fortunately they all remain deep highest occupied molecular orbital (HOMO) energy levels (-5.3 to 5.6 eV) which is very favorable to high open-circuit voltage (Voc) polymer solar cells (PSCs). By comparing the photovoltaic properties with polymers which have same backbone but do not have the bulky 2D side group in the literatures, our polymer solar cells devices show higher Voc. Especially for PQ3 (a copolymer of benzodithiophene and diketopyrrolopyrrole), the donor photon energy loss (Eg-eVoc) is 0.51 eV which is almost the lowest value achieved by the researchers. It can be concluded that: the bulky terthiophene side group helps to improve Voc of the PSCs devices. The overall performance of solar cells devices is correlated with the molecule conformation, polymer hole mobility and polymer/PCBM blend film morphology.</p

Heterologous expression facilitates the discovery and characterization of marine microbial natural products

Microbial natural products and their derivatives have been developed as a considerable part of clinical drugs and agricultural chemicals. Marine microbial natural products exhibit diverse chemical structures and bioactivities with substantial potential for the development of novel pharmaceuticals. However, discovering compounds with new skeletons from marine microbes remains challenging. In recent decades, multiple approaches have been developed to discover novel marine microbial natural products, among which heterologous expression has proven to be an effective method. Facilitated by large DNA cloning and comparative metabolomic technologies, a few novel bioactive natural products from marine microorganisms have been identified by the expression of their biosynthetic gene clusters (BGCs) in heterologous hosts. Heterologous expression is advantageous for characterizing gene functions and elucidating the biosynthetic mechanisms of natural products. This review provides an overview of recent progress in heterologous expression-guided discovery, biosynthetic mechanism elucidation, and yield optimization of natural products from marine microorganisms and discusses the future directions of the heterologous expression strategy in facilitating novel natural product exploitation

A dry lunar mantle reservoir for young mare basalts of Chang'e-5

The distribution of water in the Moon’s interior carries implications for the origin of the Moon1, the crystallization of the lunar magma ocean2 and the duration of lunar volcanism2. The Chang’e-5 mission returned some of the youngest mare basalt samples reported so far, dated at 2.0 billion years ago (Ga)3, from the northwestern Procellarum KREEP Terrane, providing a probe into the spatiotemporal evolution of lunar water. Here we report the water abundances and hydrogen isotope compositions of apatite and ilmenite-hosted melt inclusions from the Chang’e-5 basalts. We derive a maximum water abundance of 283 ± 22 μg g−1 and a deuterium/hydrogen ratio of (1.06 ± 0.25) × 10–4 for the parent magma. Accounting for low-degree partial melting of the depleted mantle followed by extensive magma fractional crystallization4, we estimate a maximum mantle water abundance of 1–5 μg g−1, suggesting that the Moon’s youngest volcanism was not driven by abundant water in its mantle source. Such a modest water content for the Chang’e-5 basalt mantle source region is at the low end of the range estimated from mare basalts that erupted from around 4.0 Ga to 2.8 Ga (refs. 5,6), suggesting that the mantle source of the Chang’e-5 basalts had become dehydrated by 2.0 Ga through previous melt extraction from the Procellarum KREEP Terrane mantle during prolonged volcanic activity