Dispersed H3K27 trimethylation (H3K27me3) of the AGAMOUS (AG) genomic locus is mediated by CURLY LEAF (CLF), a component of the Polycomb Repressive Complex (PRC) 2. Previous reports have shown that ...the AG second intron, which confers AG tissue-specific expression, harbors sequences targeted by several positive and negative regulators.
Using RACE reverse transcription polymerase chain reaction, we found that the AG intron 2 encodes several noncoding RNAs. RNAi experiment showed that incRNA4 is needed for CLF repressive activity. AG-incRNA4 RNAi lines showed increased leaf AG mRNA levels associated with a decrease of H3K27me3 levels; these plants displayed AG overexpression phenotypes.
Genetic and biochemical analyses demonstrated that the AG-incRNA4 can associate with CLF to repress AG expression in leaf tissues through H3K27me3-mediated repression and to autoregulate its own expression level.
The mechanism of AG-incRNA4-mediated repression may be relevant to investigations on tissue-specific expression of Arabidopsis MADS-box genes.
Metal−organic frameworks (MOFs), also known as coordination polymers, represent an interesting type of solid crystalline materials that can be straightforwardly self‐assembled through the ...coordination of metal ions/clusters with organic linkers. Owing to the modular nature and mild conditions of MOF synthesis, the porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre‐designing or post‐synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for exploring multifunctional MOF materials. Here, the bright potential of MOF materials as emerging multifunctional materials is highlighted in some of the most important applications for gas storage and separation, optical, electric and magnetic materials, chemical sensing, catalysis, and biomedicine.
Metal−organic frameworks, as an emerging type of solid crystalline materials, can be straightforwardly self‐assembled through the coordination of metal ions/clusters with organic linkers. The functions of MOFs can not only originate from their porosities, but can also be generated from metal ions/clusters, organic linkers/metalloligands, or a variety of guest species, making MOFs a highly versatile and tunable platform to develop multifunctional materials for their broad applications
Despite progress in the treatment of diabetic macular edema and diabetic retinopathy, the rate of lower fundus examination due to limitations of medical resources delays the diagnosis and treatment ...of diabetic retinopathy. Therefore, implementation of automated diabetic retinopathy screening program and the identification of more specific and sensitive biomarkers are important for facilitating the earlier detection of diabetic macular edema and diabetic retinopathy to decrease the prevalence of poor vision and blindness.
The realization of porous materials for highly selective separation of acetylene (C2H2) from various other gases (e.g., carbon dioxide and ethylene) by adsorption is of prime importance but ...challenging in the petrochemical industry. Herein, a chemically stable Hofmann‐type metal−organic framework (MOF), Co(pyz)Ni(CN)4 (termed as ZJU‐74a), that features sandwich‐like binding sites for benchmark C2H2 capture and separation is reported. Gas sorption isotherms reveal that ZJU‐74a exhibits by far the record C2H2 capture capacity (49 cm3 g−1 at 0.01 bar and 296 K) and thus ultrahigh selectivity for C2H2/CO2 (36.5), C2H2/C2H4 (24.2), and C2H2/CH4 (1312.9) separation at ambient conditions, respectively, of which the C2H2/CO2 selectivity is the highest among all the robust MOFs reported so far. Theoretical calculations indicate that the oppositely adjacent nickel(II) centers together with cyanide groups from different layers in ZJU‐74a can construct a sandwich‐type adsorption site to offer dually strong and cooperative interactions for the C2H2 molecule, thus leading to its ultrahigh C2H2 capture capacity and selectivities. The exceptional separation performance of ZJU‐74a is confirmed by both simulated and experimental breakthrough curves for 50/50 (v/v) C2H2/CO2, 1/99 C2H2/C2H4, and 50/50 C2H2/CH4 mixtures under ambient conditions.
A chemically stable Hofmann‐type metal−organic framework is realized for benchmark acetylene capture capacity and separation, mainly attributed to the unique sandwich‐like binding environments constructed by the oppositely adjacent open metal centers and cyanide groups from the two different Ni(CN)42− building units, thus affording a record‐high acetylene uptake at 0.01 bar and very high selectivities for acetylene‐related separation applications.
Porous materials for C2H2/CO2 separation mostly suffer from high regeneration energy, poor stability, or high cost that largely dampen their industrial implementation. A desired adsorbent should have ...an optimal balance between excellent separation performance, high stability, and low cost. We herein report a stable, low‐cost, and easily scaled‐up aluminum MOF (CAU‐10‐H) for highly efficient C2H2/CO2 separation. The suitable pore confinement in CAU‐10‐H can not only provide multipoint binding interactions with C2H2 but also enable the dense packing of C2H2 inside the pores. This material exhibits one of the highest C2H2 storage densities of 392 g L−1 and highly selective adsorption of C2H2 over CO2 at ambient conditions, achieved by a low C2H2 adsorption enthalpy (27 kJ mol−1). Breakthrough experiments confirm its exceptional separation performance for C2H2/CO2 mixtures, affording both large C2H2 uptake of 3.3 mmol g−1 and high separation factor of 3.4. CAU‐10‐H achieves the benchmark balance between separation performance, stability, and cost for C2H2/CO2 separation.
An ultra‐microporous Al‐MOF with suitable pore confinement enables the dense packing of C2H2 molecules for efficient C2H2/CO2 separation, exhibiting the benchmark balance between high separation performance, low cost, high stability, and large‐scale synthesis for industrial applications.
Tunable metasurfaces enable dynamical control of the key constitutive properties of light at a subwavelength scale. To date, electrically tunable metasurfaces at near-infrared wavelengths have been ...realized using free carrier modulation, and switching of thermo-optical, liquid crystal and phase change media. However, the highest performance and lowest loss discrete optoelectronic modulators exploit the electro-optic effect in multiple-quantum-well heterostructures. Here, we report an all-dielectric active metasurface based on electro-optically tunable III-V multiple-quantum-wells patterned into subwavelength elements that each supports a hybrid Mie-guided mode resonance. The quantum-confined Stark effect actively modulates this volumetric hybrid resonance, and we observe a relative reflectance modulation of 270% and a phase shift from 0° to ~70°. Additionally, we demonstrate beam steering by applying an electrical bias to each element to actively change the metasurface period, an approach that can also realize tunable metalenses, active polarizers, and flat spatial light modulators.
Developing porous materials to overcome the trade‐off between adsorption capacity and selectivity for C2H2/CO2 separation remains a challenge. Herein, we report a stable HKUST‐1‐like MOF (ZJU‐50a), ...featuring large cages decorated with high density of supramolecular binding sites to achieve both high C2H2 storage and selectivity. ZJU‐50a exhibits one of the highest C2H2 storage capacity (192 cm3 g−1) and concurrently high C2H2/CO2 selectivity (12) at 298 K and 1 bar. Single‐crystal X‐ray diffraction studies on gas‐loaded ZJU‐50a crystal unveil that the incorporated supramolecular binding sites can selectively take up C2H2 molecule but not CO2 to result in both high C2H2 storage and selectivity. Breakthrough experiments validated its separation performance for C2H2/CO2 mixtures, providing a high C2H2 recovery capacity of 84.2 L kg−1 with 99.5 % purity. This study suggests a novel strategy of engineering supramolecular binding sites into MOFs to overcome the trade‐off for this separation.
We developed a novel strategy by engineering abundant supramolecular binding sites into a chemically stable HKUST‐1‐like MOF (ZJU‐50a) to achieve simultaneously high C2H2 storage and selectivity, breaking the trade‐off between adsorption capacity and selectivity for C2H2/CO2 separation.
Developing porous materials for C3H6/C3H8 separation faces the challenge of merging excellent separation performance with high stability and easy scalability of synthesis. Herein, we report a robust ...Hofmann clathrate material (ZJU‐75a), featuring high‐density strong binding sites to achieve all the above requirements. ZJU‐75a adsorbs large amount of C3H6 with a record high storage density of 0.818 g mL−1, and concurrently shows high C3H6/C3H8 selectivity (54.2) at 296 K and 1 bar. Single‐crystal structure analysis unveil that the high‐density binding sites in ZJU‐75a not only provide much stronger interactions with C3H6 but also enable the dense packing of C3H6. Breakthrough experiments on gas mixtures afford both high separation factor of 14.7 and large C3H6 uptake (2.79 mmol g−1). This material is highly stable and can be easily produced at kilogram‐scale using a green synthesis method, making it as a benchmark material to address major challenges for industrial C3H6/C3H8 separation.
A novel strategy that incorporates high‐density strong binding sites into ultra‐microporous Hofmann clathrate material for dense packing of C3H6 molecules is reported. The use of this new porous material not only overcomes the trade‐off between uptake capacity and selectivity but also combines excellent separation performance with high stability, economic feasibility and easy scalability of synthesis.
Abstract
One‐step separation of C
2
H
4
from ternary C
2
mixtures by physisorbents remains a challenge to combine excellent separation performance with high stability, low cost, and easy scalability ...for industrial applications. Herein, we report a strategy of constructing negative electrostatic pore environments in a stable, low‐cost, and easily scaled‐up aluminum MOF (MOF‐303) for efficient one‐step C
2
H
2
/C
2
H
6
/C
2
H
4
separation. This material exhibits not only record high C
2
H
2
and C
2
H
6
uptakes, but also top‐tier C
2
H
2
/C
2
H
4
and C
2
H
6
/C
2
H
4
selectivities at ambient conditions. Theoretical calculations combined with in situ infrared spectroscopy indicate that multiple N/O sites on pore channels can build a negative electro‐environment to provide stronger interactions with C
2
H
2
and C
2
H
6
over C
2
H
4
. Breakthrough experiments confirm its exceptional separation performance for ternary mixtures, affording one of the highest C
2
H
4
productivity of 1.35 mmol g
−1
. This material is highly stable and can be easily synthesized at kilogram‐scale from cheap raw materials using a water‐based green synthesis. The benchmark combination of excellent separation properties with high stability and low cost in scalable MOF‐303 has unlocked its great potential in this challenging industrial separation.
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