"The writings of Mao Zedong have been circulated throughout the world more widely, perhaps, than those of any other single person this century. The “Talks at the Yan’an Conference on Literature and ...Art” has occupied a prominent position among his many works and has been the subject of intense scrutiny both within and outside China. This text has undoubted importance to modern Chinese literature and history. In particular, it reveals Mao’s views on such questions as the relationship between writers or works of literature and their audience, or the nature and value of different kinds of literary products. In this translation and commentary, Bonnie S. McDougall finds that Mao was in fact ahead of many of his critics in the West and his Chinese contemporaries in his discussion of literary issues. Unlike the majority of modern Chinese writers deeply influenced by Western theories of literature and society (including Marxism), Mao remained close to traditional patterns of thought and avoided the often mechanical or narrowly literal interpretations that were the hallmark of Western schools current in China in the early twentieth century. Many of the detailed discussions on the “Talks” in the West have been concerned with their political and historical significance. However, since Mao is a literary figure of some importance in twentieth-century China, McDougall finds it worthwhile to follow up his published remarks on the nature and source of literature and the means of its evaluation. By better understanding the complex and revolutionary ideas contained in the “Talks,” McDougall suggests we may acquire the necessary analytical tools for a more fruitful investigation into contemporary Chinese literature."
The palladium‐catalyzed Heck reaction is a well‐known, Nobel Prize winning transformation for producing alkenes. Unlike the alkenyl and aryl variants of the Heck reaction, the alkyl‐Heck reaction is ...still underdeveloped owing to the competitive side reactions of alkyl–palladium species. Herein, we describe the development of a deaminative alkyl‐Heck‐type reaction that proceeds through C−N bond activation by visible‐light photoredox catalysis. A variety of aliphatic primary amines were found to be efficient starting materials for this new process, affording the corresponding alkene products in good yields under mild reaction conditions. Moreover, this strategy was successfully applied to deaminative carbonylative alkyl‐Heck‐type reactions.
Single‐electron process: A deaminative alkyl‐Heck‐type reaction and its carbonylative variant proceed through photocatalytic C−N bond activation. This process represents a significant complement to the classic palladium‐catalyzed Heck reaction, and features easily available starting materials, good reaction efficiency, and mild reaction conditions. Tppy=2,4,6‐triphenylpyridine.
Spatial electromagnetic (EM) radiation, big data, is both an opportunity and a challenge. Harvesting and converting waste EM energy for high‐efficient recycling has a huge significance in the energy ...field. Herein, a new and effective patching engineering method using conductive polymers to repair magnetic graphene (NF‐P) is proposed, tailoring the microstructure network controllably, including conductive network and relaxation genes. It realizes the precise tuning of EM property, and the EM response shows a significant increase of 52%. The energy transformation inside materials is surveyed, and a revolutionary mode of energy conversion is constructed, ingeniously utilizing the stored electrical energy and the converted heat energy inside the material with the theoretical utilization of absorbed EM energy up to 100%. The NF‐P patching network serves as a prototype for a potential cell device with the EM energy conversion improved by ≈10 times and effective bandwidth increased by 13 GHz that covers the entire research frequency band (2–18 GHz). This research opens up a new idea for energy utilization inside materials, providing a novel and effective path for harvesting, converting and delivering spatial EM energy.
Energy is not produced, but is simply portered. Here, a revolutionary prototype cell is constructed, ingeniously utilizing the stored electrical energy and converted heat energy inside material with the theoretical utilization of absorbed electromagnetic energy up to 100%.
Two mixed‐metal gallium iodate fluorides, namely, α‐ and β‐Ba2GaF4(IO3)2(IO3) (1 and 2), have been designed by the aliovalent substitutions of α‐ and β‐Ba2VO2F2(IO3)2(IO3) (3 and 4) involving one ...cationic and two anionic sites. Both 1 and 2 display large second‐harmonic generation responses (≈6×KH2PO4 (KDP)), large energy band gaps (4.61 and 4.35 eV), wide transmittance ranges (≈0.27–12.5 μm), and high relevant laser‐induced damage thresholds (29.7× and 28.3×AgGaS2, respectively), which indicates that 1 and 2 are potential second‐order nonlinear optical materials in the ultraviolet to mid‐infrared. Our studies propose that three‐site aliovalent substitution is a facile route for the discovery of good NLO materials.
Trading places: Two new nonlinear optical materials, α‐ and β‐Ba2GaF4(IO3)2(IO3) (1 and 2), were designed via three‐site aliovalent substitution of VO4F2 in α‐ and β‐Ba2VO2F2(IO3)2(IO3) by GaO2F4. The new materials display large second‐harmonic generation responses (≈6×KH2PO4 (KDP)), wide energy band gaps (4.61 and 4.35 eV), and high laser damage thresholds (29.7× and 28.3× relative to that of AgGaS2).
Abstract
Nitric oxide (NO) has been implicated in a variety of physiological and pathological processes. Monitoring cellular levels of NO requires a sensor to feature adequate sensitivity, transient ...recording ability and biocompatibility. Herein we report a single-atom catalysts (SACs)-based electrochemical sensor for the detection of NO in live cellular environment. The system employs nickel single atoms anchored on N-doped hollow carbon spheres (Ni SACs/N-C) that act as an excellent catalyst for electrochemical oxidation of NO. Notably, Ni SACs/N-C shows superior electrocatalytic performance to the commonly used Ni based nanomaterials, attributing from the greatly reduced Gibbs free energy that are required for Ni SACs/N-C in activating NO oxidation. Moreover, Ni SACs-based flexible and stretchable sensor shows high biocompatibility and low nanomolar sensitivity, enabling the real-time monitoring of NO release from cells upon drug and stretch stimulation. Our results demonstrate a promising means of using SACs for electrochemical sensing applications.
Catalytic asymmetric cycloadditions via transition-metal-containing dipolar intermediates are a powerful tool for synthesizing chiral heterocycles. However, within the field of palladium catalysis, ...compared with the well-developed normal electron-demand cycloadditions with electrophilic dipolarophiles, a general strategy for inverse electron-demand ones with nucleophilic dipolarophiles remains elusive, due to the inherent linear selectivity in the key palladium-catalyzed intermolecular allylations. Herein, based on the switched regioselectivity of iridium-catalyzed allylations, we achieved two asymmetric 4+2 cycloadditions of vinyl aminoalcohols with aldehydes and β,γ-unsaturated ketones through synergetic iridium and amine catalysis. The activation of vinyl aminoalcohols by iridium catalysts and carbonyls by amine catalysts provide a foundation for the subsequent asymmetric 4+2 cycloadditions of the resulting iridium-containing 1,4-dipoles and (di)enamine dipolarophiles. The former provides a straightforward route to a diverse set of enantio-enriched hydroquinolines bearing chiral quaternary stereocenters, and the later represent an enantio- and diastereodivergent synthesis of chiral hydroquinolines.
Porphyry and skarn deposits in the middle Yangtze Valley within the Northern Yangtze Craton have a combined tungsten resource of ~3milliontonnes (Mt) and represent one of the most important tungsten ...regions in the world. The Dahutang porphyry tungsten deposit, with reserves of >1Mt, is one of the largest deposits. Uranium–Pb analyses for the ore-related granitoids yield ages of 147.4±0.58Ma–148.3±1.9Ma for porphyritic biotite granite, 144.7±0.47Ma–146.1±0.64Ma for fine-grained granite, and 143.0±0.76Ma–143.1±1.2Ma for granite porphyry, a progressive youngling of ages that is consistent with field observations. Geochemical data show that the three types of granite are characterized by enrichments in Rb, Pb, and U, and depletion in Ba, Nb, P, and Ti, with ASI molar Al2O3/(CaO+Na2O+K2O)>1.1 that is characteristic of a peraluminous melt. The P2O5 contents of the granites are 0.13–0.37% and have a positive correlation with SiO2, and they are thus S-type intrusions. They exhibit initial 87Sr/86Sr of 0.721 to 0.731 and εNd(t) of −5.06 to −7.99 for porphyritic biotite granite, 0.7196 to 0.7289 and −6.29 to −6.74 for fine-grained granite, and 0.7153 to 0.7365 and −5.09 to −7.64 for granite porphyry. Chondrite-normalized rare earth element (REE) patterns for the granites are characterized by enrichment in the light REE and a strong negative Eu anomaly, indicating that they were derived from the Proterozoic pelitic and psammitic basement strata and experienced strong fractional crystallization of plagioclase. Our ca. 150–140Ma age for the Dahutang S-type magmatism and W mineralization is identical to that of the I-type magmatism related to Cu–Au–Mo–Fe-bearing porphyry and skarn deposits along the middle to lower Yangtze River Valley. We propose that the latest Jurassic to earliest Cretaceous granitoids and ores formed during a tearing of the subducting Izanagi slab, which caused the upwelling of asthenosphere and resulting mantle–crust interaction. The S-type granitoids and related W ore systems resulted from the re-melting of the Proterozoic crust, whereas the I-type granitic rocks and related ores are attributed to the partial melting of the subducted slab.
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•Petrogenesis of the granitoids within Dahutang tungsten deposit, South-Central China.•Zircon U-Pb ages for granitoids obtained range from 147.4±0.58 Ma to 143.0±0.76 Ma.•Petrochemical and Sr-Nd data indicate the granitoids are remelted from the crust.•Model for the petrogenesis and related mineraliztion of the deposit was proposed.
Ferroptosis regulates cell death through reactive oxygen species (ROS)‐associated lipid peroxide accumulation, which is expected to affect the structure and polarity of lipid droplets (LDs), but with ...no clear evidence. Herein, we report the first example of an LD/nucleus dual‐targeted ratiometric fluorescent probe, CQPP, for monitoring polarity changes in the cellular microenvironment. Due to the donor–acceptor structure of CQPP, it offers ratiometric fluorescence emission and fluorescence lifetime signals that reflect polarity variations. Using nucleus imaging as a reference, CQPP was applied to report the increase in LD polarity and the homogenization of polarity between LDs and cytoplasm in the ferroptosis model. This LD/nucleus dual‐targeted fluorescent probe shows the great potential of using fluorescence imaging to study ferroptosis and ferroptosis‐related diseases.
The first lipid droplet (LD)/nucleus dual‐targeted ratiometric fluorescence probe, CQPP, for monitoring polarity change was developed. CQPP offers ratiometric fluorescence and fluorescence lifetime imaging of LD polarity variations. Using nucleus imaging as a reference, CQPP was applied to report the increase in LD polarity and the homogenization of polarity between LDs and cytoplasm in the ferroptosis model.
Carbohydrate-active enzymes (CAZymes) are very important to the biotech industry, particularly the emerging biofuel industry because CAZymes are responsible for the synthesis, degradation and ...modification of all the carbohydrates on Earth. We have developed a web resource, dbCAN (http://csbl.bmb.uga.edu/dbCAN/annotate.php), to provide a capability for automated CAZyme signature domain-based annotation for any given protein data set (e.g. proteins from a newly sequenced genome) submitted to our server. To accomplish this, we have explicitly defined a signature domain for every CAZyme family, derived based on the CDD (conserved domain database) search and literature curation. We have also constructed a hidden Markov model to represent the signature domain of each CAZyme family. These CAZyme family-specific HMMs are our key contribution and the foundation for the automated CAZyme annotation.
A copper‐catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth‐abundant metal catalyst, ...mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles. Moreover, experiments to demonstrate the synthetic potential of this methodology are performed.
Switch‐hitter: This work describes a copper‐catalyzed decarboxylative amination/hydroamination sequential reaction. The one‐pot treatment of an indoline intermediate with either an acid or a base enables the switchable synthesis of two types of functionalized indoles in generally high yields and with complete chemoselectivities (36 examples and up to 99 % yield).
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