Image Super-Resolution Reconstruction Based on L1/2 Sparsity

Based on image sparse representation in the shearlet domain, we proposed a L1/2 sparsity regularized unconvex variation model for image super-resolution. The L1/2 regularizer term constrains the underlying image to have a sparse representation in shearlet domain. The fidelity term restricts the consistency with the measured imaged in terms of the data degradation model. Then, the variable splitting algorithm is used to break down the model into a series of constrained optimization problems which can be solved by alternating direction method of multipliers. Experimental results demonstrate the effectiveness of the proposed method, both in its visual effects and in quantitative terms

Bio-Inspired Nano-Traps for Uranium Extraction from Seawater and Recovery from Nuclear Waste

Nature can efficiently recognize specific ions by exerting second-sphere interactions onto well-folded protein scaffolds. However, a considerable challenge remains to artificially manipulate such affinity, while being cost-effective in managing immense amounts of water samples. Here, we propose an effective approach to regulate uranyl capture performance by creating bio-inspired nano-traps, illustrated by constructing chelating moieties into porous frameworks, where the binding motif’s coordinative interaction towards uranyl is enhanced by introducing an assistant group, reminiscent of biological systems. Representatively, the porous framework bearing 2-aminobenzamidoxime is exceptional in sequestering high uranium concentrations with sufficient capacities (530 mg g−1) and trace quantities, including uranium in real seawater (4.36 mg g−1, triple the benchmark). Using a combination of spectroscopic, crystallographic, and theory calculation studies, it is revealed that the amino substituent assists in lowering the charge on uranyl in the complex and serves as a hydrogen bond acceptor, boosting the overall uranyl affinity of amidoxime

Postsynthetically Modified Covalent Organic Frameworks for Efficient and Effective Mercury Removal

A key challenge in environmental remediation is the design of adsorbents bearing an abundance of accessible chelating sites with high affinity, to achieve both rapid uptake and high capacity for the contaminants. Herein, we demonstrate how two-dimensional covalent organic frameworks (COFs) with well-defined mesopore structures display the right combination of properties to serve as a scaffold for decorating coordination sites to create ideal adsorbents. The proof-of-concept design is illustrated by modifying sulfur derivatives on a newly designed vinyl-functionalized mesoporous COF (COF-V) via thiol-ene "click" reaction. Representatively, the material (COF-S-SH) synthesized by treating COF-V with 1,2-ethanedithiol exhibits high efficiency in removing mercury from aqueous solutions and the air, affording He and H-g(0) capacities of 1350 and 863 mg g(-1), respectively, surpassing all those of thiol and thioether functionalized materials reported thus far. More significantly, COF-S-SH demonstrates an ultrahigh distribution coefficient value (K-d) of 2.3 X 10(9) mL g(-1), which allows it to rapidly reduce the Hg2+ concentration from 5 ppm to less than 0.1 ppb, well below the acceptable limit in drinking water (2 ppb). We attribute the impressive performance to the synergistic effects arising from densely populated chelating groups with a strong binding ability within ordered mesopores that allow rapid diffusion of mercury species throughout the material. X-ray absorption fine structure (XAFS) spectroscopic studies revealed that each Hg is bound exclusively by two S via intramolecular cooperativity in COF-S-SH, further interpreting its excellent affinity. The results presented here thus reveal the exceptional potential of COFs for high-performance environmental remediation

Rb_jM_k[Fe(CN)₆]_l (M = Co, Ni) Prussian Blue Analogue Hollow Nanocubes: a New Example of a Multilevel Pore System

A facile surfactant-free route to synthesize uniform Rb_0.4M₄[Fe­(CN)₆]_2.8·7.2H₂O (M = Co, Ni) hollow nanoparticles is described. Rb_1.6Mn₄[Fe­(CN)₆]_3.2·4.8H₂O serves as a sacrificial/removable core in the synthesis of core@shell heterostructures. After dissolution of the cores under very mild conditions, the crystalline hollow nanocubes feature well-defined micro-, meso-, and macropores. The surfactant-free approach preserves the reactivity of the Prussian blue analogue surface as evidenced by the subsequent synthesis of hollow shell@shell heterostructures

Functionalized Porous Aromatic Framework for Efficient Uranium Adsorption from Aqueous Solutions

We demonstrate the successful functionalization of a porous aromatic framework for uranium extraction from water as exemplified by grafting PAF-1 with the uranyl chelating amidoxime group. The resultant amidoxime-functionalized PAF-1 (PAF-1-CH₂AO) exhibits a high uranium uptake capacity of over 300 mg g^–1 and effectively reduces the uranyl concentration from 4.1 ppm to less than 1.0 ppb in aqueous solutions within 90 min, well below the acceptable limit of 30 ppb set by the US Environmental Protection Agency. The local coordination environment of uranium in PAF-1-CH₂AO is revealed by X-ray absorption fine structure spectroscopic studies, which suggest the cooperative binding between UO₂²⁺ and adjacent amidoxime species

How Can Proteins Enter the Interior of a MOF? Investigation of Cytochrome <i>c</i> Translocation into a MOF Consisting of Mesoporous Cages with Microporous Windows

It has been demonstrated for the first time that the heme protein cytochrome <i>c</i> (Cyt <i>c</i>) can enter the interior of a MOF despite the larger molecular dimension of the protein relative to the access pore sizes. Mechanistic studies suggest that the Cyt <i>c</i> molecules must undergo a significant conformational change during translocation into the MOF interior through the relatively small nanopores

Genomic analyses of new genes and their phenotypic effects reveal rapid evolution of essential functions in <i>Drosophila</i> development

It is a conventionally held dogma that the genetic basis underlying development is conserved in a long evolutionary time scale. Ample experiments based on mutational, biochemical, functional, and complementary knockdown/knockout approaches have revealed the unexpectedly important role of recently evolved new genes in the development of Drosophila. The recent progress in the genome-wide experimental testing of gene effects and improvements in the computational identification of new genes (< 40 million years ago, Mya) open the door to investigate the evolution of gene essentiality with a phylogenetically high resolution. These advancements also raised interesting issues in techniques and concepts related to phenotypic effect analyses of genes, particularly of those that recently originated. Here we reported our analyses of these issues, including reproducibility and efficiency of knockdown experiment and difference between RNAi libraries in the knockdown efficiency and testing of phenotypic effects. We further analyzed a large data from knockdowns of 11,354 genes (~75% of the Drosophila melanogaster total genes), including 702 new genes (~66% of the species total new genes that aged < 40 Mya), revealing a similarly high proportion (~32.2%) of essential genes that originated in various Sophophora subgenus lineages and distant ancestors beyond the Drosophila genus. The transcriptional compensation effect from CRISPR knockout were detected for highly similar duplicate copies. Knockout of a few young genes detected analogous essentiality in various functions in development. Taken together, our experimental and computational analyses provide valuable data for detection of phenotypic effects of genes in general and further strong evidence for the concept that new genes in Drosophila quickly evolved essential functions in viability during development.</p