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The direct and selective C(sp 3 )-H functionalization of cycloalkanes and alkanes is a highly useful process in organic synthesis owing to the low-cost starting materials, the high step and atom economy. Its application to asymmetric catalysis, however, has been scarcely explored. Herein, we disclose our effort toward this goal by incorporation of dual asymmetric photocatalysis by a chiral nickel catalyst and a commercially available organophotocatalyst with a radical relay strategy through sulfur dioxide insertion. Such design leads to the development of three-component asymmetric sulfonylation involving direct functionalization of cycloalkanes, alkanes, toluene derivatives or ethers. The photochemical reaction of a C(sp 3 )-H precursor, a SO 2 surrogate and a common α,β-unsaturated carbonyl compound proceeds smoothly under mild conditions, delivering a wide range of biologically interesting α-C chiral sulfones with high regio- and enantioselectivity (>50 examples, up to >50:1 rr and 95% ee). This method is applicable to late-stage functionalization of bioactive molecules, and provides an appealing access to enantioenriched compounds starting from the abundant hydrocarbon compounds. The direct and selective C(sp 3 )-H functionalization of cycloalkanes and alkanes is useful in organic synthesis but its application to asymmetric catalysis has been less explored. Here, the authors demonstrate the incorporation of a dual asymmetric photocatalyst which leads to the development of asymmetric sulfonylation involving direct functionalization of cycloalkanes, alkanes, toluene derivatives or ethers.

Development of practical deuteration reactions is highly valuable for organic synthesis, analytic chemistry and pharmaceutic chemistry. Deuterodehalogenation of organic chlorides tends to be an attractive strategy but remains a challenging task. We here develop a photocatalytic system consisting of an aryl-amine photocatalyst and a disulfide co-catalyst in the presence of sodium formate as an electron and hydrogen donor. Accordingly, many aryl chlorides, alkyl chlorides, and other halides are converted to deuterated products at room temperature in air (>90 examples, up to 99% D-incorporation). The mechanistic studies reveal that the aryl amine serves as reducing photoredox catalyst to initiate cleavage of the C-Cl bond, at the same time as energy transfer catalyst to induce homolysis of the disulfide for consequent deuterium transfer process. This economic and environmentally-friendly method can be used for site-selective D-labeling of a number of bioactive molecules and direct H/D exchange of some drug molecules. Deuterodehalogenation of organic chlorides is a useful strategy to install deuterium atoms at specific positions, however, it has several drawbacks. In this study, the authors report an organophotocatalytic system consisting of an aryl-amine-based photocatalyst and a common disulfide co-catalyst, for efficient deuteration of a wide range of aryl chlorides, alkyl chlorides and other halides, at room temperature in air.

Graphene, the thinnest, strongest, and stiffest material with exceptional thermal conductivity and electron mobility, has increasingly received world‐wide attention in the past few years. These unique properties may lead to novel or improved technologies to address the pressing global challenges in many applications including transparent conducting electrodes, field effect transistors, flexible touch screen, single‐molecule gas detection, desalination, DNA sequencing, osmotic energy production, etc. To realize these applications, it is necessary to transfer graphene films from growth substrate to target substrate with large‐area, clean, and low defect surface, which are crucial to the performances of large‐area graphene devices. This critical review assesses the recent development in transferring large‐area graphene grown on Fe, Ru, Co, Ir, Ni, Pt, Au, Cu, and some nonmetal substrates by using various synthesized methods. Among them, the transfers of the most attention kinds of graphene synthesized on Cu and SiC substrates are discussed emphatically. The advances and the main challenges of each wet and dry transfer method for obtaining the transferred graphene film with large‐area, clean, and low defect surface are also reviewed. Finally, the article concludes the most promising methods and the further prospects of graphene transfer. Graphene has increasingly received world‐wide attention in the past few years. It is necessary to transfer graphene films from growth substrate to target substrate when fabricating graphene‐based devices. This critical review assesses the recent development in transferring large‐area graphene and concludes the most promising methods and the further prospects of graphene transfer.

The selective functionalization of inert C( sp 3 )–H bonds is extremely attractive in organic synthesis and catalysis science, but the conversion of hydrocarbons lacking directing groups into chiral molecules through catalytic C( sp 3 )–H functionalization is formidably challenging. Here, to address this problem, we have developed a photochemical system consisting of a hydrogen atom transfer organophotocatalyst and a chiral catalyst containing an earth-abundant metal. With the cooperative catalysts and imine partners, a wide range of benzylic, allylic hydrocarbons and unactivated alkanes can be converted to functionalized chiral products. The readily tunable bisoxazoline catalysts of copper or other metals exhibit precise regional recognition and asymmetric induction towards these inert C–H bonds. The reactions are applicable to many compounds including small hydrocarbons, branched alkanes, cycloalkanes and more complex medicinal agents. This method provides an economic and rapid construction of optically active compounds, starting from the most basic chemical feedstocks. Selective functionalization of C( sp 3 )–H bonds is difficult in alkanes and other hydrocarbons, and especially so for enantioselective reactions. Here the authors report a photocatalyst and chiral metal catalyst to allow the radical, asymmetric addition of alkyl, allylic and benzylic groups to imines.

Multiplexing multiple orbital angular momentum (OAM) channels enables high-capacity optical communication. However, optical scattering from ambient microparticles in the atmosphere or mode coupling in optical fibers significantly decreases the orthogonality between OAM channels for demultiplexing and eventually increases crosstalk in communication. Here, we propose a novel scattering-matrix-assisted retrieval technique (SMART) to demultiplex OAM channels from highly scattered optical fields and achieve an experimental crosstalk of –13.8 dB in the parallel sorting of 24 OAM channels after passing through a scattering medium. The SMART is implemented in a self-built data transmission system that employs a digital micromirror device to encode OAM channels and realize reference-free calibration simultaneously, thereby enabling a high tolerance to misalignment. We successfully demonstrate high-fidelity transmission of both gray and color images under scattering conditions at an error rate of <0.08%. This technique might open the door to high-performance optical communication in turbulent environments.Recovering scattered data from twisted lightTwisted light beams can be made to transmit higher quality data by decoding the information present in the ‘speckle patterns’ that arise when they pass through scattering media. Lei Gong of the University of Science and Technology of China and colleagues developed the ‘scattering-matrix-assisted retrieval technique’ (SMART) to recover scattered data from multiplexed multiple orbital angular momentum (OAM) channels. These multiple twisting light beams have the potential to carry unlimited data channels, but light scattering, caused by micro-particles in the atmosphere or by energy transfer between channels, reduces data quality. The SMART platform allowed high-fidelity transmission of images, reducing the error rate by 21 times compared to previous reports. Improvements on the technique could facilitate the transfer of high quality optical data in harsh atmospheric or underwater conditions.

Copper-based asymmetric photocatalysis has great potential in the development of green synthetic approaches to chiral molecules. However, there are several formidable challenges associated with such a conception. These include the relatively weak visible light absorption, short excited-state lifetimes, incompatibility of different catalytic cycles, and the difficulty of the stereocontrol. We report here an effective strategy by means of single-electron-transfer (SET) initiated formation of radicals and photoactive intermediates to address the long-standing problems. Through elaborate selection of well-matched reaction partners, the chiral bisoxazoline copper catalyst is engaged in the SET process, photoredox catalysis, Lewis acid activation and asymmetric induction. Accordingly, a highly enantioselective photocatalytic α-aminoalkylation of acyclic imine derivatives has been accessed. This strategy sheds light on how to make use of diverse functions of a single transition metal catalyst in one reaction, and offers an economic and simplified approach to construction of highly valuable chiral vicinal diamines. Copper-based asymmetric photocatalysis has great synthetic potential, however it has been rarely exploited due to challenges inherent to such systems. Here, a chiral bisoxazoline copper catalyst is involved in a SET process, photoredox catalysis, Lewis acid activation and asymmetric induction to construct chiral vicinal diamines.

At present, SLAM is widely used in all kinds of dynamic scenes. It is difficult to distinguish dynamic targets in scenes using traditional visual SLAM. In the matching process, dynamic points are incorrectly added to the pose calculation with the camera, resulting in low precision and poor robustness in the pose estimation. This paper proposes a new dynamic scene visual SLAM algorithm based on adaptive threshold homogenized feature extraction and YOLOv5 object detection, named AHY-SLAM. This new method adds three new modules based on ORB-SLAM2: a keyframe selection module, a threshold calculation module, and an object detection module. The optical flow method is used to screen keyframes for each frame input in AHY-SLAM. An adaptive threshold is used to extract feature points for keyframes, and dynamic points are eliminated with YOLOv5. Compared with ORB-SLAM2, AHY-SLAM has significantly improved pose estimation accuracy over multiple dynamic scene sequences in the TUM open dataset, and the absolute pose estimation accuracy can be increased by up to 97%. Compared with other dynamic scene SLAM algorithms, the speed of AHY-SLAM is also significantly improved under a guarantee of acceptable accuracy.

Changes in soil carbon (C):nitrogen (N):phosphorus (P) stoichiometry have great significance on understand regulatory mechanism and restoration of ecosystem functions. However, the responses of C, N and P stoichiometry to soil depth and different vegetation types remains elusive. To address this problem, the study aims to explore the effects of soil depth and vegetation types on soil C, N, and P stoichiometry, and their relationships with microbial biomass in low mountain and hill region of China. The results indicated that soil SOC and TN concentrations in oak forest were markedly higher than those in grassland, and the vertical distribution of SOC and TN concentration showed an inverted triangle trend as the soil deepens. However, there was no significant change in soil TP concentration among 0–20 cm, 20–40 cm, and 40–60 cm. Soil C/N among different layers (0–20, 20–40, and 40–60 cm) is narrower fluctuation margin, and its value is basically stable within a certain range (11–14.5). Both soil C/P and N/P showed significant variability in different vegetation types, and soil N/P decreased with soil layers deepen. Both the microbial biomass C (MBC) and N (MBN) showed a decreasing trend with the increase of soil depth, and three soil layers from high to low was: oak forest > pine forest > grassland. Our results will potentially provide useful information for the vegetation restoration and forest management and great significance to enrich the scientific theory of ecological stoichiometry.

Background Elucidating the mechanisms underlying cold-tolerant germination is crucial for enhancing crop resilience to low temperatures. Hulless barley ( Hordeum vulgare var. coeleste L.), with remarkable natural cold adaptation, serves as an ideal model to study cold stress tolerance mechanisms in gramineous crops. In this study, cold-tolerant variety 37 and cold-sensitive variety 44 were screened and used to investigate the molecular mechanisms of cold-tolerant germination, via seed germination assays, combined with phytohormone determination, transcriptome sequencing and 16 S rRNA amplicon sequencing. Results Low temperature significantly inhibited hulless barley seed germination: the germination rate of cold-sensitive variety 44 decreased by 69%, while that of cold-tolerant variety 37 only decreased by 2%. Transcriptome analysis identified 2,647 and 2,392 differentially expressed genes (DEGs) in variety 37 and 44, respectively. Weighted gene co-expression network analysis (WGCNA) revealed a green module significantly positively correlated with gibberellic acid (GA) content, containing 10 core genes such as late embryogenesis abundant protein ( LEA ) and Homeobox genes. 16 S rRNA sequencing showed that the cold-tolerant variety 37 had enriched abundances of dominant endophytes including Sphingomonas and Pelomonas , with correlation coefficients of 0.70 and 0.87 with GA content, respectively. Additionally, exogenous GA treatment significantly increased germination rates under cold stress by 176.67% in cold-sensitive variety 44. Conclusions This study confirms that the enhanced cold tolerance of hulless barley during seed germination originates from the synergistic interaction between beneficial endophytes ( Sphingomonas , Pelomonas ), GA, and core genes (e.g., LEA , Homeobox ). Exogenous GA application can significantly restore the germination ability of cold-sensitive varieties. These findings provide a critical theoretical basis for improving cold tolerance in hulless barley germplasm.

The Paleogene braided river delta deposits in the Lenghu tectonic belt of the northern Qaidam Basin document an environmental transition critical for understanding regional petroleum systems. Through integration of petrographic (thin-section and heavy mineral analyses), geochemical (trace and rare earth element analyses), and geophysical (well logging and 2D seismic interpretation) methods, this study investigates paleoclimate, paleosalinity, paleoredox conditions, provenance, and paleosedimentary evolution. A transition from humid, freshwater, oxic to semiarid-induced brackish, suboxic conditions is revealed, characterized by increasing salinity, depth, and reducibility, particularly during the deposition of the Xiaganchaigou Formation. The Saishiteng Shan is identified as the primary sediment source, reflecting a continental island-arc setting and supplying intermediate basement igneous rocks that influence reservoir quality. Tectonoclimatically controlled depositional facies shift from braided rivers to lacustrine deltas, characterized by thin-bedded discrete sand bodies and low sand-to-mud ratios. These integrated factors highlight the critical role of tectonoclimatic coupling, aridification-enhanced evaporite seals, and intermediate igneous provenance-driven secondary porosity development in controlling reservoir architecture, source rock potential, and petroleum system evolution within the Qaidam Basin and analogous lacustrine settings.