Boosting room-temperature conversion of methane via confining Cu atoms in ultrathin Ru nanosheets




在温和条件下设计用于 CH 4活化的活性中心对于天然气的低能转化至关重要,但由于 CH 4的化学惰性和调节活性中心配位环境的困难,这仍然是一个巨大的挑战。

在此,我们报道了在具有受限Cu原子的超薄Ru纳米片上实现了在室温下将CH 4高效转化为液态C1含氧化合物。与之前报道的催化剂相比,它具有高达 1,533 mmol g -1 Cu(surf.) h -1生产率和 97.3 h -1 TOF 的优异性能,对 C1 氧化物的选择性超过 99%,并且优化的 CH 4在 25°C 时转化率达到 0.05%。多光谱分析和第一性原理计算表明,在Ru边缘受限的Cu位上产生的双配位桥位氧可以以中等低的能垒解离CH 4的C-H键,从而实现CH 4转化在室温下通过自由基机制。





Volume34, Issue36   September 8, 2022


Abstract (上下滑动查看)

Engineering a proper immune response following biomaterial implantation is essential to bone tissue regeneration. Herein, a biomimetically hierarchical scaffold composed of deferoxamine@poly(ε-caprolactone) nanoparticles (DFO@PCL NPs), manganese carbonyl (MnCO) nanosheets, gelatin methacryloyl hydrogel, and a polylactide/hydroxyapatite (HA) matrix is fabricated to augment bone repair by facilitating the balance of the immune system and bone metabolism. First, a 3D printed stiff scaffold with a well-organized gradient structure mimics the cortical and cancellous bone tissues; meanwhile, an inside infusion of a soft hydrogel further endows the scaffold with characteristics of the extracellular matrix. A Fenton-like reaction between MnCO and endogenous hydrogen peroxide generated at the implant-tissue site triggers continuous release of carbon monoxide and Mn2+, thus significantly lessening inflammatory response by upregulating the M2 phenotype of macrophages, which also secretes vascular endothelial growth factor to induce vascular formation. Through activating the hypoxia-inducible factor-1α pathway, Mn2+ and DFO@PCL NP further promote angiogenesis. Moreover, DFO inhibits osteoclast differentiation and synergistically collaborates with the osteoinductive activity of HA. Based on amounts of data in vitro and in vivo, strong immunomodulatory, intensive angiogenic, weak osteoclastogenic, and superior osteogenic abilities of such an osteoimmunity-regulating scaffold present a profound effect on improving bone regeneration, which puts forward a worthy base and positive enlightenment for large-scale bone defect repair.



Volume32, Issue37   September 12, 2022


Abstract (上下滑动查看)

Deoxyribonucleic acid (DNA) represents an important class of molecular building blocks for the assembly of supramolecular functional systems primarily due to its molecular recognition capability and sequence programmability. Eventually, DNA-based nanostructures are assembled in a way that their states remain at the thermodynamic minimum of the energy. However, active life-like functions and their interactive adaption require the integration of energy away from thermodynamic equilibrium. The construction of DNA-based artificial systems was often inspired by the naturally occurring dissipative assembly processes, which leads to the consumption of energy to maintain the thermodynamically non-equilibrium state. In this review, the recent progress of the fabrications and properties of DNA-based dissipative assembly systems toward nanoarchitectonics is summarized. It focuses on the principle of dissipative assembly and shows some pioneering examples of DNA-based dissipative assembly systems. The latest corresponding perspectives are also proposed.



Volume 94, Issue 31   August 9, 2022


Abstract (上下滑动查看)

Protein networks can be assembled in vitro for basic biochemistry research, drug screening, and the creation of artificial cells. Two standard methodologies are used: manual pipetting and pipetting robots. Manual pipetting has limited throughput in the number of input reagents and the combination of reagents in a single sample. While pipetting robots are evident in improving pipetting efficiency and saving hands-on time, their liquid handling volume usually ranges from a few to hundreds of microliters. Microfluidic methods have been developed to minimize the reagent consumption and speed up screening but are challenging in multifactorial protein studies due to their reliance on complex structures and labeling dyes. Here, we engineered a new impact-printing-based methodology to generate printed microdroplet arrays containing water-in-oil droplets. The printed droplet volume was linearly proportional (R2 = 0.9999) to the single droplet number, and each single droplet volume was around 59.2 nL (coefficient of variation = 93.8%). Our new methodology enables the study of protein networks in both membrane-unbound and -bound states, without and with anchor lipids DGS–NTA(Ni), respectively. The methodology is demonstrated using a subnetwork of mitogen-activated protein kinase (MAPK). It takes less than 10 min to prepare 100 different droplet-based reactions, using <1 μL reaction volume at each reaction site. We validate the kinase (ATPase) activity of MEK1 (R4F)* and ERK2 WT individually and together under different concentrations, without and with the selective membrane attachment. Our new methodology provides a reagent-saving, efficient, and flexible way for protein network research and related applications.



Volume 23, Issue 9   September 12, 2022


Abstract (上下滑动查看)

Covalent bonds and noncovalent interactions play crucial roles in enzyme self-assembly. Here, we designed a Tag/Catcher system named NGTag/NGCatcher in which the Catcher is a highly charged protein that can bind proteins with positively charged tails and rapidly form a stable isopeptide bond with NGTag. In this study, we present a multienzyme strategy based on covalent bonds and noncovalent interactions. In vitro, mCherry, YFP, and GFP can form protein-rich three-dimensional networks based on NGCatcher, NGTag, and RK (Arginine/Lysine) tails, respectively. Furthermore, this technology was applied to improve lycopene production in Escherichia coli. Three key enzymes were involved in lycopene production variants from Deinococcus wulumuqiensis R12 of NGCatcher_CrtE, NGTag_Idi, and RKIspARK, where the multienzyme complexes were clearly observed in vivo and in vitro, and the lycopene production in vivo was 17.8-fold higher than that in the control group. The NGTag/NGCatcher system will provide new opportunities for in vivo and in vitro multienzyme catalysis.



Volume35, 2022




Volume 43 ,Issue 9    September 9 2022




Volume 1,   Issue 9   2022


Abstract (上下滑动查看)

Holographic technology shows great potential in data storage, three-dimensional display, and artificial intelligence, etc. The theoretical unbounded physical dimension of the orbital angular momentum (OAM) has been used as an information carrier in holography, resulting in the concept of OAM holography. However, the state of the illumination beam in the traditional holographic decoding process is based on phase modulation, resulting in a long switching time (generally no more than 30 Hz). The switching rate is physically determined by the switching speed of the illumination beam state. Currently, it is limited by the refresh rate of the phase-modulated spatial light modulator, which limits the future development of ultra-high-speed OAM-addressable dynamic holography.

This cover paper proposes a new concept of cross convolution aiming at high-speed extracting information from the OAM multiplexing hologram. They design a special amplitude-modulated pattern to illuminate the hologram in order to extract a specific picture based on the cross convolution relation between a series of spatial frequency components of the amplitude-modulated pattern and the OAM-multiplexing hologram in spatial frequency domain. With the help of the digital micromirror device, the amplitude-modulated pattern can be loaded and switched on the illumination beam at a frame rate of several kilohertz, so that holographic video can be played at this frame rate by using this technology which leads to a two-orders of magnitude increase of information extraction speed in OAM holography in principle. In their experiment, the significant digits of the value are encoded in the hologram, and they show that the first 100 significant digits are emerged quickly at a speed of 100 Hz as shown in the figure. The typical example of high-speed reconstruction of digits proves that the scheme can not only support holographic video, but also show the potential in construction of a high-capacity short-range optical communication system.



Volume 49, Issue 8   2022


Abstract (上下滑动查看)

Non-volatile memory(NVM),also known as persistent memory(PM),has the characteristics of bit-based addressing,durability,high storage density and low latency.Although the latency of NVM is much smaller than that of solid-state drives,it is greater than that of DRAM.In addition,NVM has shortcomings such as unbalanced reading and writing as well as short writing life.Therefore,currently NVM cannot completely replace DRAM.A more reasonable method is using NVM to build a hybrid memory architecture based on DRAM+NVM.Based on the observation that many data accesses in database applications are skewed,this paper focuses on the hybrid memory architecture composed of NVM and DRAM and proposes a hotspot data-based speedup method for persistent memory indices.Particularly,we utilize the low latency of DRAM and the durability and high sto-rage density of NVM,and propose to add a DRAM-based hotspot-data cache for persistent memory indices.Then,we present a query-adaptive indexing method that can automatically adjust the cache according to the change of hotspot data.We apply the proposed method to several persistent memory indices,including wBtree,FPTree and Fast&Fair,and conduct comparative experiments.The results show that when the number of hotspot data visits accounts for 80% of the total visits,the proposed method can accelerate the query performance of the three indices by 52%,33% and 37%,respectively.