In the “post‐Moore's Law” era, new materials are highly expected to bring next revolutionary technologies in electronics and optoelectronics, wherein 2D materials are considered as very promising ...candidates beyond bulk materials due to their superiorities of atomic thickness, excellent properties, full components, and the compatibility with the processing technologies of traditional complementary metal‐oxide semiconductors, enabling great potential in fabrication of logic, storage, optoelectronic, and photonic 2D devices with better performances than state‐of‐the‐art ones. Toward the massive applications of highly integrated 2D devices, large‐size 2D single crystals are a prerequisite for the ultimate quality of materials and extreme uniformity of properties. However, at present, it is still very challenging to grow all 2D single crystals into the wafer scale. Therefore, a systematic understanding for controlled growth of various 2D single crystals needs to be further established. Here, four key aspects are reviewed, i.e., nucleation control, growth promotion, surface engineering, and phase control, which are expected to be controllable at different periods during the growth. In addition, the perspectives on designed growth and potential applications are discussed for showing the bright future of these advanced material systems of 2D single crystals.
To obtain large‐size 2D single crystals, systematic understanding of the designed growth of 2D materials needs to be further established. Thereby, effective controls based on interfacial engineering are summarized from four critical aspects: nucleation control, growth promotion, surface engineering, and phase control. Furthermore, prospects for the bright future of 2D single crystals are also provided.
Under visible light irradiation, o-phosphinophenolate functions as an easily accessible photoredox catalyst to activate trifluoromethyl groups in trifluoroacetamides, trifluoroacetates, and ...trifluoromethyl (hetero)arenes to deliver corresponding difluoromethyl radicals. It works in relay with a thiol hydrogen atom transfer (HAT) catalyst to enable selective defluoroalkylation and hydrodefluorination. The reaction allows for the facile synthesis of a broad scope of difluoromethylene-incorporated carbonyl and (hetero)aromatic compounds, which are valuable fluorinated intermediates of interest in the pharmaceutical industry. The ortho-diphenylphosphino substituent, which is believed to facilitate photoinduced electron transfer, plays an essential role in the redox reactivity of phenolate. In addition to trifluoromethyl groups, pentafluoroethyl groups could also be selectively defluoroalkylated.
PurposeThe socialist political economy with Chinese characteristics is a systematic economic discipline, which theoretically summarises the socialist economic system and the path of economic ...development with Chinese characteristics. It is a systematic economic theory of adapting Marxism to the Chinese context. The theoretical system construction for the discipline of socialist political economy with Chinese characteristics is currently a major task.Design/methodology/approachFrom the perspective of disciplinary cognition, the theoretical system of the discipline of socialist political economy with Chinese characteristics includes the disciplinary attributes and connotations, theoretical basis, the origin of thoughts, major principles, logical starting point, main logic and problem-based study of major theoretical and practical issues.FindingsDeveloping the discipline and building the theoretical system of the socialist political economy with Chinese characteristics, several major principles should be adhered to, including building the socialist political economy with Chinese characteristics on the basis of historical materialism; building the theoretical paradigm of socialist political economy with Chinese characteristics around the analysis of production relations; adhering to the people-centred principle; taking common prosperity as the main logic of the socialist political economy with Chinese characteristics; studying the major theoretical and practical issues of building the socialism with Chinese characteristics in the new era based on problems; and reflecting the innovative development of the discipline in the textbook, The Socialist Political Economy with Chinese Characteristics.Originality/valueDisciplinary cognition involves the connotations, attributes, mission and development path of the discipline, which is related to how to construct the discipline system and is a significant part of the disciplinary construction.
Thiol is known to act as a hydrogen atom transfer catalyst working in synergy with a photocatalyst in photoredox catalysis, but we report herein that an arene thiolate with an appropriate substituent ...can be photoactivated under visible light to function as both a strongly reducing electron-donating redox catalyst and a HAT catalyst to enable catalytic C–F activation of trifluoromethyl substrates for selective hydrodefluorination and coupling with various alkenes in the presence of formate salts. These reactions demonstrate the promising utility of arenethiolates as dual function photocatalysts. The synthetic utility of this method is demonstrated by the broad scope of amenable trifluoromethyl substrates, including trifluoromethylated (hetero)arenes, trifluoroacetates, and trifluoroacetamides, which exhibited high levels of chemoselectivity. The reaction efficacy allows site-selective late-stage functionalization of multitrifluoromethylated bioactive compounds and pharmaceuticals
This paper discusses Heller’s aesthetic ethics in her feeling theory. ‘Feeling’ is an aesthetic problem as well as an ethical problem. Heller discusses the important role of emotions in modern life. ...‘Housekeeping of feelings’ is the key category of Heller’s ethical aesthetics, which is related to one’s self-realization. It is beneficial to the formation of individual value and helps to reconstruct an increasingly atomized community. The housekeeping of feelings is some kind of care, which is important both ethically and aesthetically. Heller’s feelings theory is based on human value itself, which is of great methodological significance for the reconstruction of the broken emotional community in the post-epidemic era.
Following the first experimental realization of graphene, other ultrathin materials with unprecedented electronic properties have been explored, with particular attention given to the heavy group-IV ...elements Si, Ge and Sn. Two-dimensional buckled Si-based silicene has been recently realized by molecular beam epitaxy growth, whereas Ge-based germanene was obtained by molecular beam epitaxy and mechanical exfoliation. However, the synthesis of Sn-based stanene has proved challenging so far. Here, we report the successful fabrication of 2D stanene by molecular beam epitaxy, confirmed by atomic and electronic characterization using scanning tunnelling microscopy and angle-resolved photoemission spectroscopy, in combination with first-principles calculations. The synthesis of stanene and its derivatives will stimulate further experimental investigation of their theoretically predicted properties, such as a 2D topological insulating behaviour with a very large bandgap, and the capability to support enhanced thermoelectric performance, topological superconductivity and the near-room-temperature quantum anomalous Hall effect.
In the present study, the morphological changes on a gold electrode during the oxygen reduction (ORR) and oxygen evolution reaction (OER) processes in a dimethyl sulfoxide (DMSO)-based electrolyte ...solution were investigated using an electrochemical atomic force microscope (EC-AFM) with the help of vibrational spectroscopy measurements. The growth of the ORR products on the electrode surface, which was mainly assigned to lithium peroxide (Li2O2), was directly confirmed by the EC-AFM. It was found that the water concentration in the solution significantly affects the morphology of the ORR products. The growth of anisotropic Li2O2 particles on the gold electrode surface has been confirmed to be an electrochemical process. No evidence was found to support the disproportionation growth mechanism. These ORR products were fully decomposed at a potential as high as 4.4 V (vs Li+/Li) in the subsequent OER process, more positive than that determined by a surface-enhanced Raman spectroscopy (SERS) measurement. Combined with infrared absorption spectroscopy and SERS measurements, we propose that the oxidation decomposition of the Li2O2 deposits first occurs at its interface with the gold electrode surface, while that of the remaining particles takes place at a higher overpotential. On the contrary, the ORR deposits could be fully decomposed at a potential as low as 3.6 V when tetrathiafulvalene (TTF) was included in the solution. We confirmed by EC-AFM that the electrochemically generated TTF+ can mediate the decomposition of the Li2O2 at a lower potential through a homogeneous oxidation mechanism.
MicroRNAs play important roles in regulating tumour development, progression and metastasis. Here we show that one of the miR-200 family members, miR-141, is under-expressed in several prostate ...cancer (PCa) stem/progenitor cell populations in both xenograft and primary patient tumours. Enforced expression of miR-141 in CD44
and bulk PCa cells inhibits cancer stem cell properties including holoclone and sphere formation, as well as invasion, and suppresses tumour regeneration and metastasis. Moreover, miR-141 expression enforces a strong epithelial phenotype with a partial loss of mesenchymal phenotype. Whole-genome RNA sequencing uncovers novel miR-141-regulated molecular targets in PCa cells including the Rho GTPase family members (for example, CDC42, CDC42EP3, RAC1 and ARPC5) and stem cell molecules CD44 and EZH2, all of which are validated as direct and functionally relevant targets of miR-141. Our results suggest that miR-141 employs multiple mechanisms to obstruct tumour growth and metastasis.
Fifteen transcription factors in the CAMTA (calmodulin binding transcription activator) family of soybean were reported to differentially regulate in multiple stresses; however, their functional ...analyses had not yet been attempted. To characterize their role in stresses, we first comprehensively analyzed the
family in silico and thereafter determined their expression pattern under drought. The bioinformatics analysis revealed multiple stress-related
-regulatory elements including
,
,
and
, 10 unique miRNA (microRNA) targets in
transcripts and 48 proteins in GmCAMTAs' interaction network. We then cloned the 2769 bp CDS (coding sequence) of
in an expression vector and overexpressed in soybean and Arabidopsis through
-mediated transformation. The T3 (Transgenic generation 3) stably transformed homozygous lines of Arabidopsis exhibited enhanced tolerance to drought in soil as well as on MS (Murashige and Skoog) media containing mannitol. In their drought assay, the average survival rate of transgenic Arabidopsis lines OE5 and OE12 (Overexpression Line 5 and Line 12) was 83.66% and 87.87%, respectively, which was ~30% higher than that of wild type. In addition, the germination and root length assays as well as physiological indexes such as proline and malondialdehyde contents, catalase activity and leakage of electrolytes affirmed the better performance of OE lines. Similarly,
overexpression in soybean promoted drought-efficient hairy roots in OE chimeric plants as compare to that of VC (Vector control). In parallel, the improved growth performance of OE in Hoagland-PEG (polyethylene glycol) and on MS-mannitol was revealed by their phenotypic, physiological and molecular measures. Furthermore, with the overexpression of
, the downstream genes including
,
,
and
were upregulated in Arabidopsis. Likewise, in soybean hairy roots,
,
and
were significantly upregulated as a result of
overexpression and majority of these upregulated genes in both plants possess CAMTA binding
motif in their promoters. Taken together, we report that
plays substantial role in tolerance of soybean against drought stress and could prove to be a novel candidate for engineering soybean and other plants against drought stress. Some research gaps were also identified for future studies to extend our comprehension of
-mediated stress regulatory mechanisms.
The precise precursor supply is a precondition for controllable growth of two-dimensional (2D) transition metal dichalcogenides (TMDs). Although great efforts have been devoted to modulating the ...transition metal supply, few effective methods of chalcogen feeding control were developed. Here we report a strategy of using active chalcogen monomer supply to grow high-quality TMDs in a robust and controllable manner, e.g., MoS
monolayers perform representative photoluminescent circular helicity of ~92% and electronic mobility of ~42 cm
V
s
. Meanwhile, a uniform quaternary TMD alloy with three different anions, i.e., MoS
Se
Te
, was accomplished. Our mechanism study revealed that the active chalcogen monomers can bind and diffuse freely on a TMD surface, which enables the effective nucleation, reaction, vacancy healing and alloy formation during the growth. Our work offers a degree of freedom for the controllable synthesis of 2D compounds and their alloys, benefiting the development of high-end devices with desired 2D materials.
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