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•The development of anion coordination chemistry: from recognition to self-assembly.•Typical anion ligands based on hydrogen bonding.•Anion-coordination-based supramolecular ...assemblies.•Anion–π interaction and halogen bonding in designing anion ligands and assemblies.
The field of anion coordination chemistry has received more and more attention in recent years. A large number of articles, from the initial anion recognition to various applications, have been published in the past few decades. This review will focus on the recent progress in this fast-growing field, emphasizing the anion-ligand coordination properties from structural and geometrical aspects. Firstly, typical anion ligands based on hydrogen bonding are briefly summarized. This is followed by a collection of representative and the most recent examples of anion coordination compounds, whose structures are analyzed in terms of hydrogen bonding parameters and coordination number and geometry. In the third part, recent achievements in anion coordination-based supramolecular assemblies are discussed, and finally developments of two non-classical interactions (anion–π interactions and halogen bonding) in anion coordination and self-assembly processes are also described.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Single-walled carbon nanotubes (SWCNTs) have been attracting tremendous attention owing to their structure (chirality) dependent outstanding properties, which endow them with great potential in a ...wide range of applications. The preparation of chirality-pure SWCNTs is not only a great scientific challenge but also a crucial requirement for many high-end applications. As such, research activities in this area over the last two decades have been very extensive. In this review, we summarize recent achievements and accumulated knowledge thus far and discuss future developments and remaining challenges from three aspects: controlled growth, postsynthesis sorting, and characterization techniques. In the growth part, we focus on the mechanism of chirality-controlled growth and catalyst design. In the sorting part, we organize and analyze existing literature based on sorting targets rather than methods. Since chirality assignment and quantification is essential in the study of selective preparation, we also include in the last part a comprehensive description and discussion of characterization techniques for SWCNTs. It is our view that even though progress made in this area is impressive, more efforts are still needed to develop both methodologies for preparing ultrapure (e.g., >99.99%) SWCNTs in large quantity and nondestructive fast characterization techniques with high spatial resolution for various nanotube samples.
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IJS, KILJ, NUK, PNG, UL, UM
In this study, the polyphenols composition and antioxidant properties of 12 blue highland barley varieties planted on the Qinghai-Tibet Plateau area were measured. The contents of the free, bound and ...total phenolic acids varied between 166.20-237.60, 170.10-240.75 and 336.29-453.94 mg of gallic acid equivalents per 100 g of dry weight (DW) blue highland barley grains, while the free and bound phenolic acids accounted for 50.09% and 49.91% of the total phenolic acids, respectively. The contents of the free, bound and total flavones varied among 20.61-25.59, 14.91-22.38 and 37.91-47.98 mg of catechin equivalents per 100 g of dry weight (DW) of blue highland barley grains, while the free and bound flavones accounted for 55.90% and 44.10% of the total flavones, respectively. The prominent phenolic compounds in the blue hulless barley grains were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, naringenin, hesperidin, rutin, (+)-catechin and quercetin. Among these, protocatechuic acid, chlorogenic acid and (+)-catechin were the major phenolic compounds in the free phenolics extract. The most abundant bound phenolics were gallic acid, benzoic acid, syringic acid, 4-coumaric acid, benzoic acid, dimethoxybenzoic acid, naringenin, hesperidin, quercetin and rutin. The average contribution of the bound phenolic extract to the DPPH
free radical scavenging capacity was higher than 86%, that of free phenolic extract to the ABTS
free radical scavenging capacity was higher than 79%, and that of free phenolic (53%) to the FRAP antioxidant activity was equivalent to that of the bound phenol extract (47%). In addition, the planting environment exerts a very important influence on the polyphenol composition, content and antioxidant activity of blue highland barley. The correlation analysis showed that 2,4-hydroxybenzoic acid and protocatechuic acid were the main contributors to the DPPH
and ABTS
free radical scavenging capacity in the free phenolic extract, while chlorogenic acid, vanillic acid, ferulic acid and quercetin were the main contributors to the free radical scavenging capacity in the bound phenol extract. The study results show that the blue highland barley grains have rich phenolic compounds and high antioxidant activity, as well as significant varietal differences. The free and bound phenolic extracts in the blue hulless barley grains have an equivalent proportion in the total phenol, and co-exist in two forms. They can be used as a potential valuable source of natural antioxidants, and can aid in enhancing the development and daily consumption of foods relating to blue highland barley.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Activated carbons were prepared from walnut shells by vacuum chemical activation with zinc chloride as the activation agent. To optimize the preparation method, the effects of the main process ...parameters (such as system pressure, activation temperature, and impregnation ratio) on the properties (expressed in terms of specific surface area and pore volume) of the obtained activated carbons were studied. It was found that the optimum activated carbon obtained with system pressure of 30
kPa, activation temperature of 450
°C, and impregnation ratio of 2.0 has a BET surface area of 1800
m
2/g and total pore volume of 1.176
cm
3/g. The prepared activated carbons were characterized by SEM, TEM, and FTIR. Then they were used as an adsorbent for the removal of methylene blue from aqueous solutions. The results showed that the methylene blue adsorption capacity was positively correlated to the BET surface area. The highest methylene blue adsorption capacity was 315
mg/g for the optimum activated carbon. The effect of the dose of the activated carbon was evaluated and the adsorption isotherm of methylene blue was determined. Redlich–Peterson and Langmuir–Freundlich models were found to best represent the equilibrium data, suggesting heterogeneous surface adsorption of methylene blue on the activated carbon.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
An azobenzene‐functionalized bis‐bis(urea) ligand (Lazo) and phosphate anion assemble to give the first photoactive “aniono” constructs, tetrahedron (A4L6) and helicate (A2L3), which readily undergo ...interconversion through cis‐trans isomerization of the azo group under irradiation/heating. Most strikingly, the tetrahedral cage can accommodate an 18crown‐6 molecule, which can capture two tetramethylammonium (TMA+) ions with an unusually high affinity, even capable of replacing K+ in K(18crown‐6)+ to form a {(TMA)2⊂
(18crown‐6)}⊂
cage “Russian doll” structure. Thus, the current work may provide a model for the light‐driven binding and exchange of the biologically important K+ and TMA+ ions.
Anion‐coordination‐driven assembly from an azobenzene‐functionalized bis‐bis(urea) ligand (Lazo) with phosphate anion affords the first photoactive A4L6‐type tetrahedral cage. The tetrahedral cage can reversibly trap two TMA+ cations and one 18crown‐6 molecule with an unusually high affinity accompanied by the release/capture of K+ ion from K(18crown‐6)+ under irradiation/heating.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The rapid development of nanotechnology offers a variety of potential therapeutic strategies for cancer treatment. High atomic element nanomaterials are often utilized as radiosensitizers due to ...their unique photoelectric decay characteristics. Among them, gold nanoparticles (GNPs) are one of the most widely investigated and are considered to be an ideal radiosensitizers for radiotherapy due to their high X-ray absorption and unique physicochemical properties. Over the last few decades, multi-disciplinary studies have focused on the design and optimization of GNPs to achieve greater dosing capability and higher therapeutic effects and highlight potential mechanisms for radiosensitization of GNPs. Although the radiosensitizing potential of GNPs has been widely recognized, its clinical translation still faces many challenges. This review analyses the different roles of GNPs as radiosensitizers in cancer radiotherapy and summarizes recent advances. In addition, the underlying mechanisms of GNP radiosensitization, including physical, chemical and biological mechanisms are discussed, which may provide new directions for the optimization and clinical transformation of next-generation GNPs.
With the continuous development and improvement of China's social economy, and the improvement of social living standards and abilities has led to increasingly strict requirements on the quality of ...life, more and more attention has been paid to education in China. Driven by the current social development, applied linguistics is developing and making progress. Its corresponding language research methods and the reform and innovation of language application have undergone further changes, and great research achievements have also been achieved. At present, with the open development of social economy and the comprehensive coverage of scientific information technology, language learning and communication have gradually become an important part of learning and education. With the emergence and development of cognitive linguistics, corpus, statistics, special English and computer languages, applied linguistics has become a nationalized research system in its research development. This paper makes an empirical investigation and analysis of the corresponding situation through the research method of applied linguistics, and reflects the development of current applied linguistics through data.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The 2019 coronavirus disease (COVID-19) has spread worldwide, and its associated stressors have resulted in decreased sleep quality among front-line workers. However, in China, the general public ...displayed more psychological problems than the front-line workers during the pandemic. Therefore, we investigated the influence of perceived stress on the sleep quality of the non-diseased general public and developed a moderated mediation model to explain said relationship.
Questionnaire-based surveys were conducted online from February 18–25, 2020 with 1630 Chinese participants (aged 18–68 years).
Around one-third (36.38%) of participants were poor sleepers during the COVID-19 pandemic. Moreover, higher perceived stress was significantly associated with higher anxiety levels, which, in turn, was associated with lower sleep quality. Self-esteem moderated the indirect effect of perceived stress on sleep quality through its moderation of the effect of perceived stress on anxiety. This indicated that the mediation effect of anxiety was stronger in those with low levels of self-esteem than in those with high levels of self-esteem.
These findings suggest that both the sleep quality and perceived stress levels of the non-diseased general public required attention during the COVID-19 pandemic. Our findings also identify personality characteristics related to better sleep quality, demonstrating the important role of self-esteem in environmental adaptation.
•One-third of the 1630 participants were poor sleepers during the pandemic.•Higher perceived stress was related to lower sleep quality.•Anxiety mediated the relationship between perceived stress and sleep quality.•Anxiety as a mediator was stronger in those with low (vs. high) self-esteem.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, we systematically summarize the chord configuration method in harmonic writing, start from the connection principle of functional harmony, and use the knowledge of harmonic theory to ...research and explain the harmonic variability writing and chord configuration method. Secondly, based on big data algorithms, it is proposed that according to the chord composition law and progression logic, a chord system construction objective function is proposed, and a dynamic planning algorithm for automatic chord arrangement is designed to realize automatic chord arrangement by machine. Then, after reducing the chord repetition rate of the generated music, it was found that the ideal style type of music could not be achieved. For this problem, a hidden Markov-based chord auto-configuration model is proposed for optimization and experimental analysis of the chord configuration method in harmonic writing is carried out. The results show that the emotional response of the major triad music fragment with an octave decrease in overall pitch is a positive emotion, and the intensity of the emotion is significantly reduced compared to the major triad with no pitch change. The emotional response to the music fragment of the major triad with an octave increase in overall pitch was positive, and the emotional intensity of the major triad with no pitch change was significantly increased. This study improved students’ musical aesthetics, cognitive abilities, and experiences.
Summary
Proanthocyanidins (PAs) have antioxidant properties and are beneficial to human health. The fruit of apple (Malus × domestica Borkh.), especially the peel, is rich in various flavonoids, such ...as PAs, and thus is an important source of dietary antioxidants. Previous research on the regulation of PAs in apple has mainly focussed on the transcription level, whereas studies conducted at the post‐transcriptional level are relatively rare. In this study, we investigated the function of mdm‐miR858, a miRNA with multiple functions in plant development, in the peel of apple fruit. We showed that mdm‐miR858 negatively regulated PA accumulation by targeting MdMYB9/11/12 in the peel. During fruit development, mdm‐miR858 expression was negatively correlated with MdMYB9/11/12 expression and PA accumulation. A 5′‐RACE experiment, GUS staining assays and transient luminescent assays indicated that mdm‐miR858 cleaved and inhibited the expression of MdMYB9/11/12. Overexpression of mdm‐miR858 in apple calli, tobacco and Arabidopsis reduced the accumulation of PAs induced by overexpression of MdMYB9/11/12. Furthermore, we found that MdBBX22 bound to the mdm‐miR858 promoter and induced its expression. Overexpression of MdBBX22 induced the expression of mdm‐miR858 to inhibit the accumulation of PAs in apple calli overexpressing MdMYB9/11/12. Under light stress, MdBBX22 induced mdm‐miR858 expression to inhibit PA accumulation and thereby indirectly enhanced anthocyanin synthesis in the peel. The present results revealed that the MdBBX22–miR858–MdMYB9/11/12 module regulates PA accumulation in apple. The findings provide a reference for further studies of the regulatory mechanism of PA accumulation and the relationship between PAs and anthocyanins.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
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