ABO genotype alters the gut microbiota by regulating GalNAc levels in pigs.

The composition of the intestinal microbiome varies considerably between individuals and is correlated with health1. Understanding the extent to which, and how, host genetics contributes to this variation is essential yet has proved to be difficult, as few associations have been replicated, particularly in humans2. Here we study the effect of host genotype on the composition of the intestinal microbiota in a large mosaic pig population. We show that, under conditions of exacerbated genetic diversity and environmental uniformity, microbiota composition and the abundance of specific taxa are heritable. We map a quantitative trait locus affecting the abundance of Erysipelotrichaceae species and show that it is caused by a 2.3 kb deletion in the gene encoding N-acetyl-galactosaminyl-transferase that underpins the ABO blood group in humans. We show that this deletion is a ≥3.5-million-year-old trans-species polymorphism under balancing selection. We demonstrate that it decreases the concentrations of N-acetyl-galactosamine in the gut, and thereby reduces the abundance of Erysipelotrichaceae that can import and catabolize N-acetyl-galactosamine. Our results provide very strong evidence for an effect of the host genotype on the abundance of specific bacteria in the intestine combined with insights into the molecular mechanisms that underpin this association. Our data pave the way towards identifying the same effect in rural human populations.

Heterodimensional superlattice with in-plane anomalous Hall effect.

Superlattices-a periodic stacking of two-dimensional layers of two or more materials-provide a versatile scheme for engineering materials with tailored properties1,2. Here we report an intrinsic heterodimensional superlattice consisting of alternating layers of two-dimensional vanadium disulfide (VS2) and a one-dimensional vanadium sulfide (VS) chain array, deposited directly by chemical vapour deposition. This unique superlattice features an unconventional 1T stacking with a monoclinic unit cell of VS2/VS layers identified by scanning transmission electron microscopy. An unexpected Hall effect, persisting up to 380 kelvin, is observed when the magnetic field is in-plane, a condition under which the Hall effect usually vanishes. The observation of this effect is supported by theoretical calculations, and can be attributed to an unconventional anomalous Hall effect owing to an out-of-plane Berry curvature induced by an in-plane magnetic field, which is related to the one-dimensional VS chain. Our work expands the conventional understanding of superlattices and will stimulate the synthesis of more extraordinary superstructures.

3D Carbon Fiber Skeleton Film Modified with Gradient Cu Nanoparticles as Auxiliary Anode Regulates Dendrite-Free, Bottom-Up Zinc Deposition.

Achieving stable Zn plating/stripping under high current density and large area capacity remains a major challenge for metal Zn anodes. To address this issue, common filter paper is utilized to construct 3D carbon fiber skeleton film modified with gradient Cu nanoparticles (CFF@Cu). The original zincophobic hydrophilic CFF is transformed into gradient zincophilic and reversed gradient hydrophilic composite, due to the gradient distribution of Cu nanoparticles. When CFF@Cu is placed above Zn foil as an auxiliary anode, Zn foil anode exhibits stable, reversible, and dendrite-free Zn plating/stripping for 1200 h at 10 mA cm-2 and 2 mAh cm-2, 2000 h at 2 mA cm-2 and 2 mAh cm-2, 340 h at 10 mA cm-2 and 10 mAh cm-2. Additionally, nucleation barrier of Zn, Zn2+ transport and deposition kinetics are improved. The deposits on the Zn foil anode become homogeneous, dense, and fine. Side reactions and by-products are effectively inhibited. The excellent performance is mainly attributed to the gradient zincophilic field in 3D CFF. A portion of Zn2+ is captured by Cu and deposited within CFF@Cu from bottom to top, which reduces and homogenizes Zn2+ flux on Zn foil, as well as weakens and homogenizes electric field on Zn foil.

Tuning Electronic Structure and Composition of FeNi Nanoalloys for Enhanced Oxygen Evolution Electrocatalysis via a General Synthesis Strategy.

Developing low-cost and efficient oxygen evolution electrocatalysts is key to decarbonization. A facile, surfactant-free, and gram-level biomass-assisted fast heating and cooling synthesis method is reported for synthesizing a series of carbon-encapsulated dense and uniform FeNi nanoalloys with a single-phase face-centered-cubic solid-solution crystalline structure and an average particle size of sub-5 nm. This method also enables precise control of both size and composition. Electrochemical measurements show that among Fex Ni(1- x ) nanoalloys, Fe0.5 Ni0.5 has the best performance. Density functional theory calculations support the experimental findings and reveal that the optimally positioned d-band center of O-covered Fe0.5 Ni0.5 renders a half-filled antibonding state, resulting in moderate binding energies of key reaction intermediates. By increasing the total metal content from 25 to 60 wt%, the 60% Fe0.5 Ni0.5 /40% C shows an extraordinarily low overpotential of 219 mV at 10 mA cm-2 with a small Tafel slope of 23.2 mV dec-1 for the oxygen evolution reaction, which are much lower than most other FeNi-based electrocatalysts and even the state-of-the-art RuO2 . It also shows robust durability in an alkaline environment for at least 50 h. The gram-level fast heating and cooling synthesis method is extendable to a wide range of binary, ternary, quaternary nanoalloys, as well as quinary and denary high-entropy-alloy nanoparticles.

Chemical Vapor Deposition of Superconducting FeTe1-xSex Nanosheets.

FeTe1-xSex, a promising layered material used to realize Majorana zero modes, has attracted enormous attention in recent years. Pulsed laser deposition (PLD) and molecular-beam epitaxy (MBE) are the routine growth methods used to prepare FeTe1-xSex thin films. However, both methods require high-vacuum conditions and polished crystalline substrates, which hinder the exploration of the topological superconductivity and related nanodevices of this material. Here we demonstrate the growth of the ultrathin FeTe1-xSex superconductor by a facile, atmospheric pressure chemical vapor deposition (CVD) method. The composition and thickness of the two-dimensional (2D) FeTe1-xSex nanosheets are well controlled by tuning the experimental conditions. The as-prepared FeTe0.8Se0.2 nanosheet exhibits an onset superconducting transition temperature of 12.4 K, proving its high quality. Our work offers an effective strategy for preparing the ultrathin FeTe1-xSex superconductor, which could become a promising platform for further study of the unconventional superconductivity in the FeTe1-xSex system.

Highly Stable and Ultrahigh-Rate Li Metal Anode Enabled by Fluorinated Carbon Fibers.

The advanced energy storage of an Li metal substituted for graphite anode can provide a significant enhancement in a battery's energy density. Nevertheless, the practical implementation of metallic Li has seriously been fettered by the notorious Li dendrite growth and the huge volumetric variation of Li metal inducing poor cycling performance and safety concerns. In this regard, constructing a robust SEI layer combined with a 3D host to stabilize the Li metal is strongly in demand. Herein, a highly stable hosted Li with an LiF dominated SEI has successfully been achieved through metal-free fluorinated carbon fibers (FCF) with strong lithiophilicity. The metal-free design is cost-effective and can retain the energy density of the Li metal, minimizing the unnecessary energy sacrifice from the extra high gravimetric density lithiophilic sites. The FCF hosted Li delivers a promoted high Coulombic efficiency, homogeneous Li deposition, and ultrahigh rate stable cycling over 1000 cycles at 20 mA cm-2 with a much lower voltage polarization (≈220 mV). Moreover, half cells coupled with LiNi0.8 Co0.1 Mn0.1 O2 , sulfur or even thick LiCoO2 cathode demonstrate superior rate performances and enhanced cycling stability even under a lean electrolyte. This work proves the feasibility of FCF hosted Li for practical usage and provides a novel approach toward cost-effective and high performance lithium metal batteries.

Gas-solid interfacial charge transfer in volatile organic compound detection by CuCrO2nanoparticles.

Nanostructured metal oxide semiconductors have received great attention used as the chemiresistive layer of gas sensor to detect the volatile organic compound recently. As indispensable complementary parts for dominative n-type semiconductors, the p-type metal oxides based gas sensors fail to be studied sufficiently, which hampers their practical applications. In this work, the p-type delafossite CuCrO2nanoparticles were synthesized, characterized, and tested for gas sensing, followed by the first principles calculations to simulate the generation of chemiresistive signal. The hydrothermal synthesis time of CuCrO2nanoparticles is optimized as 24 h with a higher proportion of oxygen vacancies but a smaller size, which is confirmed by the microscopy and spectrum characterization and allows for a prevailing gas sensitivity. Meanwhile, this CuCrO2gas sensor is proven to perform a higher selectivity to n-propanol and a low detection limit of 1 ppm. The adsorption sites and charge variations of dehydrogenation at the gas-solid interface predicted by the theoretical analysis are claimed to be crucial to such selectivity. It is an innovative approach to understand the chemiresistive gas sensing by evaluating the preference of charge transfer between the sensor and target gaseous molecule, which provides a new route to precisely design and develop the advanced sensing devices for the diverse applications.

Confining Tiny MoO2 Clusters into Reduced Graphene Oxide for Highly Efficient Low Frequency Microwave Absorption.

Herein, a supermolecular-scale cage-confinement pyrolysis strategy is proposed to build two dielectric electromagnetic wave absorbents, in which MoO2 nanoparticles are sandwiched uniformly between porous carbon shells and reduced graphene oxide (RGO). Both sandwich structures are derived from hybrid hydrogels doped by two different crosslinkers (with/without oxygen bridge), which can precisely confine Mo source (e.g., PMo12 ). Without adding magnetic components, both absorbents exhibit excellent low frequency absorption performance in combination with electrically tunable ability and enhanced reflection loss value, which is superior over other relative 2D dielectric absorbers and satisfies the requirements of portable electronics. Notably, introducing oxygen bridges in the crosslinker generates a more stable confining configuration, which in turn renders its corresponding derivative exhibiting an extra multifrequency electromagnetic wave absorption trait. The intrinsic electromagnetic wave adjustment mechanism of the ternary hybrid absorbent is also explored. The result reveals that the elevated electromagnetic wave absorbing property is attributed to moderate attenuation constant and glorious impendence matching. The cage-confinement pyrolysis route to fabricate 2D MoO2 -based dielectric electromagnetic wave absorbents opens a new path for the design of electromagnetic wave absorbents used in multi/low frequency.

Metal-organic framework derived Co3Se4@Nitrogen-doped porous carbon as a high-performance anode material for lithium ion batteries.

In this paper, Co3Se4 nanoparticles embedded in nitrogen-doped porous carbon polyhedra are synthesized via a facile one-step thermal selenization, using zeolitic imidazolate framework-67 (ZIF-67) as the template. The electrochemical properties of the fabricated nanocomposite are evaluated for use as anodes for lithium ion batteries and found to exhibit a specific capacity (950 mAh g-1 at 0.2 C) and excellent cyclic stability (899 mAh g-1 at 1 C after 1000 cycles). Both are much higher than those of the state-of-the-art Co-Se based nanocomposites. This extraordinary lithium storage is attributed to the synergetic effect between the Co3Se4 nanocrystals and nitrogen-doped porous carbon framework, and is believed to offer a potential candidate anode material for next-generation lithium ion batteries.

Nanostructured Metal-Organic Conjugated Coordination Polymers with Ligand Tailoring for Superior Rechargeable Energy Storage.

Conjugated coordination polymers have become an emerging category of redox-active materials. Although recent studies heavily focus on the tailoring of metal centers in the complexes to achieve stable electrochemical performance, the effect on different substitutions of the bridging bonds has rarely been studied. An innovative tailoring strategy is presented toward the enhancement of the capacity storage and the stability of metal-organic conjugated coordination polymers. Two nanostructured d-π conjugated compounds, Ni[C6 H2 (NH)4 ]n (Ni-NH) and Ni[C6 H2 (NH)2 S2 ]n (Ni-S), are evaluated and demonstrated to exhibit hybrid electrochemical processes. In particular, Ni-S delivers a high reversible capacity of 1164 mAh g-1 , an ultralong stability up to 1500 cycles, and a fully recharge ability in 67 s. This tailoring strategy provides a guideline to design future effective conjugated coordination-polymer-based electrodes.

Unravelling the genetic loci for growth and carcass traits in Chinese Bamaxiang pigs based on a 1.4 million SNP array.

Bamaxiang pig is from Guangxi province in China, characterized by its small body size and two-end black coat colour. It is an important indigenous breed for local pork market and excellent animal model for biomedical research. In this study, we performed genomewide association studies (GWAS) on 43 growth and carcass traits in 315 purebred Bamaxiang pigs based on a 1.4 million SNP array. We observed considerable phenotypic variability in the growth and carcass traits in the Bamaxiang pigs. The corresponding SNP based heritability varied greatly across the 43 traits and ranged from 9.0% to 88%. Through a conditional GWAS, we identified 53 significant associations for 35 traits at p value threshold of 10-6 . Among which, 26 associations on chromosome 3, 7, 14 and X passed a genomewide significance threshold of 5 × 10-8 . The most remarkable loci were at around 30.6 Mb on chromosome 7, which had growth stage-dependent effects on body lengths and cannon circumferences and showed large effects on multiple carcass traits. We discussed HMGA1 NUDT3, EIF2AK1, TMEM132C and AFF2 that near the lead SNP of significant loci as plausible candidate genes for corresponding traits. We also showed that including phenotypic covariate in GWAS can help to reveal additional significant loci for the target traits. The results provide insight into the genetic architecture of growth and carcass traits in Bamaxiang pigs.

Single-Nanowire Fuse for Ionization Gas Detection.

Local electric field enhancement is crucial to detect gases for an ionization gas sensor. Nanowires grown collectively along the identical lattice orientation have been claimed to show a strong tip effect in many previous studies. Herein, we propose a novel ionization gas detector structure by using a single crystalline silicon nanowire as one electrode that is placed above the prepatterned nanotips. A significant improvement of the local electric field in its radical direction was obtained leading to an ultralow operation voltage for gas breakdown. Different from the tip of the nanowire in the reported ionization gas sensors, the gaseous discharge current in this device flows towards the sidewall in the case of a trace amount of gas environment change. Technically, this discharge current brings about a sudden temperature rise followed by a fusion of the silicon nanowire. Such unique fusibility of a single nanowire in this gas detection device suggests a novel architecture that is portable and in-site executable and can be used as an integrated gas environmental monitor.

Phase Transformation of GeO2 Glass to Nanocrystals under Ambient Conditions.

Theoretically, the accomplishment of phase transformation requires sufficient energy to overcome the barriers of structure rearrangements. The transition of an amorphous structure to a crystalline structure is implemented traditionally by heating at high temperatures. However, phase transformation under ambient condition without involving external energy has not been reported. Here, we demonstrate that the phase transformation of GeO2 glass to nanocrystals can be triggered at ambient conditions when subjected to aqueous environments. In this case, continuous chemical reactions between amorphous GeO2 and water are responsible for the amorphous-to-crystalline transition. The dynamic evolution process is monitored by using in situ liquid-cell transmission electron microscopy, clearly revealing this phase transformation. It is the hydrolysis of amorphous GeO2 that leads to the formation of clusters with a size of ∼0.4 nm, followed by the development of dense liquid clusters, which subsequently aggregate to facilitate the nucleation and growth of GeO2 nanocrystals. Our finding breaks the traditional understanding of phase transformation and will bring about a significant revolution and contribution to the classical glass-crystallization theories.

The Electrochemical Response of Single Crystalline Copper Nanowires to Atmospheric Air and Aqueous Solution.

In this paper, single crystalline copper nanowires (CuNWs) have been electrochemically grown through anodic aluminum oxide template. The environmental stability of the as-obtained CuNWs in both 40% relative humidity (RH) atmosphere and 0.1 m NaOH aqueous solution has been subsequently studied. In 40% RH atmosphere, a uniform compact Cu2 O layer is formed as a function of exposure time following the logarithmic law and epitaxially covers the CuNW surfaces. It is also found that the oxide layers on CuNWs are sequentially grown when subjected to the cyclic voltammetry measurement in 0.1 m NaOH solution. An epitaxially homogeneous Cu2 O layer is initially formed over the surface of the CuNW substrates by solid-state reaction (SSR). Subsequently, the conversion of Cu2 O into epitaxial CuO based on the SSR takes place with the increase of applied potential. This CuO layer is partially dissolved in the solution forming Cu(OH)2 , which then redeposited on the CuNW surfaces (i.e., dissolution-redeposition (DR) process) giving rise to a mixed polycrystalline CuO/Cu(OH)2 layer. The further increase of applied potential allows the complete oxidation of Cu2 O into CuO to form a dual-layer structure (i.e., CuO inner layer and Cu(OH)2 outer layer) with random orientations through an enhanced DR process.

1.2-W average-power, 700-W peak-power, 100-ps dissipative soliton resonance in a compact Er:Yb co-doped double-clad fiber laser.

Mode-locked pulses in the dissipative soliton resonance (DSR) regime enable extremely high pulse energy, but typically have the limited peak power of <100 W and a nanosecond-long pulse duration. In this Letter, we demonstrate high-peak-power, ultrashort DSR pulses in a compact Er:Yb co-doped double-clad fiber laser. The linear cavity is simply formed by two fiber loop mirrors (FLMs) using a 50/50 optical coupler (OC) and a 5/95 OC. The 5/95 FLM with a short loop length of 3 m is not only used as the output mirror, but also acts as a nonlinear optical loop mirror for initiating high-peak-power DSR. In particular, the mode-locked laser can deliver ∼100 ps DSR pulses with a maximum average power of 1.2 W and a peak power as high as ∼700 W. This is, to the best of our knowledge, the highest peak power of DSR pulses obtained in mode-locked fiber lasers.

Gamma radiation effects in amorphous silicon and silicon nitride photonic devices.

Understanding radiation damage is of significant importance for devices operating in radiation-harsh environments. In this Letter, we present a systematic study on gamma radiation effects in amorphous silicon and silicon nitride guided wave devices. It is found that gamma radiation increases the waveguide modal effective indices by as much as 4×10-3 in amorphous silicon and 5×10-4 in silicon nitride at 10 Mrad dose. This Letter further reveals that surface oxidation and radiation-induced densification account for the observed index change.

New insight into the roles of oxygen vacancies in hematite for solar water splitting.

Oxygen vacancies play an important role in the performance improvement of oxide semiconductors as photoanodes for water splitting, such as TiO2, WO3, and Fe2O3. Conductivity improvement due to the presence of oxygen vacancies was reported to be the main reason for the enhanced performance. However, oxygen vacancies may also affect light absorption and charge transfer through the solid/electrolyte interface. The roles of oxygen vacancies have not been thoroughly discussed in the past. Herein, with hematite as an example, the effects of oxygen vacancies on bulk charge transport and surface catalysis are quantitatively analyzed by decoupling photon absorption, interfacial charge transfer and charge separation processes. Oxygen vacancies improve the charge separation of both pristine and Ti-doped hematite. However, opposite observations are found in the charge transfer process for pristine and Ti-doped hematite: the positive effect in pristine hematite but the negative effect in the Ti-doped one. An electrochemical technique is used to analyze the different influences on pristine and Ti-doped hematite to unravel the mechanism of the opposite observations caused by oxygen vacancies. The current study sheds lights on how oxygen vacancies affect various aspects of important factors behind PEC performance, which is helpful to the development of more efficient photoanodes in the future.

[Preliminary study on premixed materials of emulsion gel].

The purpose of this paper was to study the pre-mixed materials of emulsion gel. Accessories were screened and formula was designed with the most common use, low cost and simple process as the standards. Experiments were designed by central composite design-response surface methodology (ccd-rsm). 8.0.6 Trial Design-Expert was used for data processing and analysis, and subjective scores were used as the index to draw the three-dimensional effect surface and 2D contour maps. It was determined that the optimal ranges were A (carbomer 940)： 0.05-0.065 g; B (castor oil)： 1.00-1.12 mL; C (poly polysorbate-80)： 0.15 mL. The optimal formula was as follows： carbopol 0.057 5 g, castor oil 1.1 mL, polysorbate-80 0.15 mL. The formulated substrate was studied on its preliminary stability and rheology characteristics, such as viscosity and thixotropy. Then with the optimal formula as substrate, emulsion type gel was prepared respectively with 98% rutin, 98% berberine hydrochloride, and 98% berbamine hydrochloride as the main component. With 0.9% normal saline as the absorption solution, the results showed that the ransdermal flux of the three formulations of 1 h was all less than 1%. The results indicated that this substrate had the potential to be developed into a premixed material. The emulsion type gel matrix made from this formula had a good appearance, stability to certain extent, appropriate viscosity and thixotropy, and showed no skin irritation in 1 h.

Low-loss photonic device in Ge-Sb-S chalcogenide glass.

Low-loss waveguides constitute an important building block for integrated photonic systems. In this work, we investigated low-loss photonic device fabrication in Ge23Sb7S70 chalcogenide glass using electron beam lithography followed by plasma dry etching. High-index-contrast waveguides with a low propagation loss of 0.5 dB/cm and microdisk resonators with an intrinsic quality factor (Q-factor) of 1.2×106 were demonstrated. Both figures represent, to the best of our knowledge, the best low-loss results reported thus far in submicrometer single-mode chalcogenide glass devices.