Electro-Induced Phase Transformation of a Conductive Metal-Organic Framework Film for Nonlinear Optical Switching.

Achieving metal-organic frameworks (MOFs) with nonlinear optical (NLO) switching is profoundly important. Herein, the conductive MOFs Cu-TCNQ phase I (Ph-I) and phase II (Ph-II) films were prepared using the liquid-phase-epitaxial layer-by-layer spin-coating method and steam heating method, respectively. Electronic experiments showed that the Ph-II film could be changed into the Ph-I film under an applied electric field. The third-order NLO results revealed that the Ph-I film had a third-order nonlinear reverse saturation absorption (RSA) response and the Ph-II film displayed a third-order nonlinear saturation absorption (SA) response. With increases in the heating time and applied voltage, the third-order NLO response realized the reversible transition between SA and RSA. The theoretical calculations indicated that Ph-I possessed more interlayer charge transfer, resulting in a third-order nonlinear RSA response that was stronger than that of Ph-II. This work applies phase-transformed MOFs to third-order NLO switching and provides new insights into the nonlinear photoelectric applications of MOFs.

The role of m5C methyltransferases in cardiovascular diseases.

The global leading cause of death is cardiovascular disease (CVD). Although advances in prevention and treatment have been made, the role of RNA epigenetics in CVD is not fully understood. Studies have found that RNA modifications regulate gene expression in mammalian cells, and m5C (5-methylcytosine) is a recently discovered RNA modification that plays a role in gene regulation. As a result of these developments, there has been renewed interest in elucidating the nature and function of RNA "epitranscriptomic" modifications. Recent studies on m5C RNA methylomes, their functions, and the proteins that initiate, translate and manipulate this modification are discussed in this review. This review improves the understanding of m5C modifications and their properties, functions, and implications in cardiac pathologies, including cardiomyopathy, heart failure, and atherosclerosis.

Cu/Cu2O nanocrystals for electrocatalytic carbon dioxide reduction to multi-carbon products.

We demonstrate the electrochemical conversion of carbon dioxide into multi-carbon products catalyzed by Cu/Cu2O nanocrystals, with a maximum C2+ faradaic efficiency of 75% in 0.10 M K2SO4 aqueous solution at -2.0 V versus Ag/AgCl and a partial current density of 34 mA cm-2.

SnS2/polypyrrole for high-efficiency photocatalytic oxidation of benzylamine.

Here, SnS2/polypyrrole (PPy) was synthesized, which shows high catalytic activity for the photocatalytic oxidation of benzylamine under mild conditions (at 25 °C, in air and without adding an additional sacrificial reagent, redox mediator and photosensitizer).

Cu3(BTC)2 nanoflakes synthesized in an ionic liquid/water binary solvent and their catalytic properties.

Low-dimensional metal-organic frameworks (MOFs) exhibit enhanced properties compared with three-dimensional (3D) geometry MOFs in many fields. In this work, we demonstrate the synthesis of Cu3(BTC)2 (BTC = benzene-1,3,5-tricarboxylate) nanoflakes in a binary solvent of ionic liquid (IL) and water. Such a MOF architecture has a high surface area and abundant unsaturated coordination metal sites, making them attractive for adsorption and catalysis. For example, in catalyzing the oxidation reactions of a series of alcohols, the Cu3(BTC)2 nanoflakes exhibit a high performance that is superior to Cu3(BTC)2 microparticles synthesized in a conventional solvent. Experimental and theoretical studies reveal that the IL accelerates the crystallization of Cu3(BTC)2, while water plays a role in stripping the Cu3(BTC)2 blocks that are formed at an early stage through its attack on the crystal plane of Cu3(BTC)2. Such an in situ crystallization-exfoliation process that uses an IL/water solvent opens a new route for producing low-dimensional MOFs.

ZIF-9(III) nanosheets synthesized in ionic liquid/ethanol mixture for efficient photocatalytic hydrogen production.

To improve the photocatalytic performance of metal-organic frameworks is of great importance. We synthesized the nanosheets of a zeolitic imidazolate framework (ZIF-9(III)) in ionic liquid/ethanol solution, with an average thickness of 4.6 nm. The as-synthesized ZIF-9(III) nanosheets have optoelectronic properties superior to the three-dimensional ZIF-9(III) synthesized by the conventional solvothermal method. The ZIF-9(III) nanosheets exhibit high activity for photocatalytic hydrogen production under visible light irradiation. The maximum hydrogen production rate can reach 112.37 mmol g-1 h-1, while that by three-dimensional ZIF-9(III) is 29.64 mmol g-1 h-1 under the same experimental conditions.

Periodically nanoporous hydrogen-bonded organic frameworks for high performance photocatalysis.

The development of highly catalytic hydrogen-bonded organic frameworks (HOFs) is of great importance, but remains challenging. Herein, we demonstrate the fabrication of a periodically nanoporous HOF for high performance photocatalysis. Compared with the conventional microporous HOFs, the nanoporous HOF architecture has a larger number of free carboxyl groups on the surface and presents greatly improved photoelectrochemical properties. It exhibits high catalytic activity for the photo-oxidative coupling of amines under mild conditions such as air atmosphere and room temperature and without any co-catalysts, sacrificial reagents or photosensitizers. The relationship between the structure, properties and catalytic performance of the nanoporous HOF was studied by experimental and theoretical investigations. It shows that such a HOF structure facilitates reactant adsorption and O2 dissociation, thus promoting the oxidative coupling reaction. This work provides a new way for improving the catalytic performance of a single HOF.

Co(NO3)2/covalent organic framework nanoparticles for high-efficiency photocatalytic oxidation of thioanisole.

Herein, we demonstrated a highly efficient photocatalytic sulfide oxidation reaction at ambient conditions without a sacrificial reagent or redox mediator, by using Co(NO3)2/covalent organic framework nanoparticles as a photocatalyst.

Annexin A protein family in atherosclerosis.

Atherosclerosis, a silent chronic vascular pathology, is the cause of the majority of cardiovascular ischaemic events. Atherosclerosis is characterized by a series of deleterious changes in cellularity, including endothelial dysfunction, transmigration of circulating inflammatory cells into the arterial wall, pro-inflammatory cytokines production, lipid accumulation in the intima, vascular local inflammatory response, atherosclerosis-related cells apoptosis and autophagy. Proteins of Annexin A (AnxA) family, the well-known Ca2+ phospholipid-binding protein, have many functions in regulating inflammation-related enzymes and cell signaling transduction, thus influencing cell adhesion, migration, differentiation, proliferation and apoptosis. There is now accumulating evidence that some members of the AnxA family, such as AnxA1, AnxA2, AnxA5 and AnxA7, play major roles in the development of atherosclerosis. This article discusses the major roles of AnxA1, AnxA2, AnxA5 and AnxA7, and the multifaceted mechanisms of the main biological process in which they are involved in atherosclerosis. Considering these evidences, it has been proposed that AnxA are drivers- and not merely participator- on the road to atherosclerosis, thus the progression of atherosclerosis may be prevented by targeting the expression or function of the AnxA family proteins.

Anchoring Ionic Liquid in Copper Electrocatalyst for Improving CO2 Conversion to Ethylene.

Electrochemical conversion of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. The Cu-based catalysts feature unique superiorities, but achieving high ethylene selectivity is still restricted. In this study, we propose the anchoring of an ionic liquid (IL) on a Cu electrocatalyst for improving the electrochemical CO2 reduction to ethylene. In a water-based electrolyte and a commonly used H-type cell, a high ethylene Faradaic efficiency of 77.3 % was achieved at -1.49 V (vs. RHE). Experimental and theoretical studies reveal that an IL can modify the electronic structure of a Cu catalyst through its interaction with Cu, making it more conducive to *CO dimerization for ethylene formation.

Weekly Variations of Intracerebral Hemorrhage Occurrence Among Different Populations: A Cross-Sectional Study.

Background and purpose: The causes of the higher incidence of intracerebral hemorrhage (ICH) on a given day are unclear. Previous studies have shown that it may vary by region and population. The purpose of this study was to detect weekly variations in ICH occurrence in southwest China and to assess differences in ICH occurrence among different populations. Methods: This hospital-based study included patients with first-onset ICH that occurred from January 1, 2012, to December 31, 2019. The weekly variation in ICH occurrence was analyzed and stratified by sex, age, comorbidities, living habits, and residence. Results: A total of 5,038 patients with first-onset ICH were enrolled. ICH occurrence was higher on Monday [odds ratio (OR), 1.22; 95% CI, 1.09-1.36; P < 0.001] and Friday (OR, 1.15; 95% CI, 1.03-1.28; P < 0.001) among all patients, and this pattern was consistent with that of men, whereas women showed a higher incidence on Mondays, Saturdays, and Sundays. The increase in the number of ICH events on Monday and Friday was pronounced in the age range of 41-60 years; however, no significant weekly variation in ICH occurrence was observed among other age groups. After stratifying by comorbidities, a significant weekly variation in ICH occurrence was observed in patients with hypertension or diabetes. Smoking and alcohol consumption was associated with a higher incidence of ICH on Friday; otherwise, a Monday excess was observed. The urban population demonstrated a significant weekly variation in ICH occurrence, whereas the rural population did not. Conclusions: Intracerebral hemorrhage occurrence showed weekly variations in southwest China and was significantly affected by sex, age, comorbidities, living habits, and residence. This suggests that weekly variations in ICH occurrence maybe dependent on the region and population.

Circadian variations in the occurrence of first-ever intracerebral hemorrhage from different sources of income: a hospital-based cross-sectional study.

BACKGROUND: The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, the purpose of our study was to investigate the Circadian Variations in the occurrence of ICH from different sources of income. METHODS: This retrospective study enrolled 4,327 patients with first-ever ICH. Based on the time of day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners, and Freelancers. Demographic and risk factors of patients were then summarized, and the circadian variation of the 3 groups of patients' known time of onset and those stratified by sex and age were analyzed. RESULTS: The frequency of ICH onset exhibited significant circadian variation among the 3 income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, and the same peak was observed in their subgroups of sex and age. In the 3 income source groups, there was a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by sex and age, the second peak was between 18:01 and 21:00 for female in Farmers, female in Freelancers, under 65 years of age in Wage-earners and 65 years or older in Freelancers, while 15:01 and 18:00 for the other groups. CONCLUSIONS: Different circadian variations of ICH onset time are found in patients with different income sources in southwest China's Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours may be closely related to the working style and living habits of people with different income sources.

Epitaxial Growth of Highly Transparent Metal-Porphyrin Framework Thin Films for Efficient Bifacial Dye-Sensitized Solar Cells.

Bifacial dye-sensitized solar cells (DSSCs) are regarded as promising solar energy conversion devices with high efficiency and less resource consumption. In this work, a highly transparent and efficient counter electrode (CE) is fabricated by introducing highly dispersed single Pt atoms doped into the van der Waals layer-by-layer epitaxially grown Zn-TCPP thin film (Zn-TCPP-Pt). The resulting Zn-TCPP-Pt CE has similar catalytic activity to commercial Pt CE but shows a better light transmission capacity in the range of visible light. The bifacial DSSC with Zn-TCPP-Pt thin film CE achieves high power conversion efficiencies of 5.48 and 4.88% under front-side and rear-side irradiation, respectively. With maximized atomic efficiency, excellent performance was obtained with about 1% Pt content and highly transparent CEs. Therefore, the light energy resource utilization rate of such less Pt and transparence CE is greatly improved in bifacial dye-sensitized solar cells, making it a promising candidate to replace Pt CE.

Cross-Linked Aptamer-Lipid Micelles for Excellent Stability and Specificity in Target-Cell Recognition.

The specific binding ability of DNA-lipid micelles (DLMs) can be increased by the introduction of an aptamer. However, supramolecular micellar structures based on self-assemblies of amphiphilic DLMs are expected to demonstrate low stability when interacting with cell membranes under certain conditions, which could lead to a reduction in selectivity for targeting cancer cells. We herein report a straightforward cross-linking strategy that relies on a methacrylamide branch to link aptamer and lipid segments. By an efficient photoinduced polymerization process, covalently linked aptamer-lipid units help stabilize the micelle structure and enhance aptamer probe stability, further improving the targeting ability of the resulting nanoassembly. Besides the development of a facile cross-linking method, this study clarifies the relationship between aptamer-lipid concentration and the corresponding binding ability.

Aptamer-based multifunctional ligand-modified UCNPs for targeted PDT and bioimaging.

We designed an aptamer-based multifunctional ligand which, upon conjugation to the surface of upconversion nanoparticles (UCNPs), could realize phase transfer, covalent photosensitizer (PS) loading, and cancer cell targeting in one simple step. The as-built PDT nanodrug is selectively internalized into cancer cells and it exhibits highly efficient and selective cytotoxicity.

Helical carbon tubes derived from epitaxial Cu-MOF coating on textile for enhanced supercapacitor performance.

The design and development of the supercapacitors containing metal oxides and carbon materials is very important for energy-storage devices in laboratory and industry. In this study, we report a helical carbon tube material derived from epitaxial Cu-MOF coating on textile by calcination treatment. The electrochemical performance obtained from the cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and cyclic stability measurements indicates that such a hybrid carbon material with a unique structure has a very high areal capacitance of 1812 mF cm-2 at a current density of 1 mA cm-2, and the material also has a good recyclability of 90% after 2000 cycles. This study combines the advantages of MOF- and cotton textile-derived carbon materials, and this study can serve as a guidance to improve the capacitance performance of supercapacitors.

Thiol-ene click chemistry: a biocompatible way for orthogonal bioconjugation of colloidal nanoparticles.

Bioconjugation based on crosslinking primary amines to carboxylic acid groups has found broad applications in protein modification, drug development, and nanomaterial functionalization. However, proteins, which are made up of amino acids, typically give nonselective bioconjugation when using primary amine-based crosslinking. In order to control protein orientation and activity after conjugation, selective bioconjugation is desirable. We herein report an efficient and cysteine-selective thiol-ene click reaction-based bioconjugation strategy using colloidal nanoparticles. The resulting thiol-ene based aptamer and enzyme nanoconjugates demonstrated excellent target binding ability and enzymatic activity, respectively. Thus, thiol-ene click chemistry can provide a stable and robust crosslinker in a biocompatible manner for bioconjugation of any thiol-containing biomolecule with nanomaterials. This will open more opportunities for applications of thiol-ene reactions and functional colloidal nanoparticles in chemical biology.

Molecular Elucidation of Disease Biomarkers at the Interface of Chemistry and Biology.

Disease-related biomarkers are objectively measurable molecular signatures of physiological status that can serve as disease indicators or drug targets in clinical diagnosis and therapy, thus acting as a tool in support of personalized medicine. For example, the prostate-specific antigen (PSA) biomarker is now widely used to screen patients for prostate cancer. However, few such biomarkers are currently available, and the process of biomarker identification and validation is prolonged and complicated by inefficient methods of discovery and few reliable analytical platforms. Therefore, in this Perspective, we look at the advanced chemistry of aptamer molecules and their significant role as molecular probes in biomarker studies. As a special class of functional nucleic acids evolved from an iterative technology termed Systematic Evolution of Ligands by Exponential Enrichment (SELEX), these single-stranded oligonucleotides can recognize their respective targets with selectivity and affinity comparable to those of protein antibodies. Because of their fast turnaround time and exceptional chemical properties, aptamer probes can serve as novel molecular tools for biomarker investigations, particularly in assisting identification of new disease-related biomarkers. More importantly, aptamers are able to recognize biomarkers from complex biological environments such as blood serum and cell surfaces, which can provide direct evidence for further clinical applications. This Perspective highlights several major advancements of aptamer-based biomarker discovery strategies and their potential contribution to the practice of precision medicine.

Versatile surface engineering of porous nanomaterials with bioinspired polyphenol coatings for targeted and controlled drug delivery.

The development of biocompatible drug delivery systems with targeted recognition and controlled release has experienced a number of design challenges, including, for example, complicated preparation steps and premature drug release. Herein, we address these problems through an in situ self-polymerization method that synthesizes biodegradable polyphenol-coated porous nanomaterials for targeted and controlled drug delivery. As a proof of concept, we synthesized polyphenol-coated mesoporous silica nanoparticles, termed MSN@polyphenol. The polyphenol coatings not only improved colloidal stability and prevented premature drug leakage, but also provided a scaffold for immobilization of targeting moieties, such as aptamers. Both immobilization of targeting aptamers and synthesis of polyphenol coating are easily accomplished without the aid of any other organic reagents. Importantly, the polyphenol coating (EGCg) used in this study could be biodegraded by acidic pH and intracellular glutathione, resulting in the release of trapped anticancer drugs. Based on confocal fluorescence microscopy and cytotoxicity experiments, drug-loaded and polyphenol-coated MSNs were shown to possess highly efficient internalization and an apparent cytotoxic effect on target cancer, but not control, cells. Our results suggest that these highly biocompatible and biodegradable polyphenol-coated MSNs are promising vectors for controlled-release biomedical applications and cancer therapy.

DNA micelle flares: a study of the basic properties that contribute to enhanced stability and binding affinity in complex biological systems.

DMFs are spherical DNA-diacyllipid nanostructures formed by hydrophobic effects between lipid tails coupled to single-stranded DNAs. Such properties as high cellular permeability, low critical micelle concentration (CMC) and facile fabrication facilitate intracellular imaging and drug delivery. While the basic properties of NFs have been amply described and tested, few studies have characterized the fundamental properties of DMFs with particular respect to aggregation number, dissociation constant and biostability. Therefore, to further explore their conformational features and enhanced stability in complex biological systems, we herein report a series of characterization studies. Static light scattering (SLS) demonstrated that DMFs possess greater DNA loading capacity when compared to other DNA-based nanostructures. Upon binding to complementary DNA (cDNA), DMFs showed excellent dissociation constants (Kd) and increased melting temperatures, as well as constant CMC (10 nM) independent of DNA length. DMFs also present significantly enhanced stability in aqueous solution with nuclease and cell lysate. These properties make DMFs ideal for versatile applications in bioanalysis and theranostics studies.