Self-Aggregation Control of Porphyrin for Enhanced Selective Covalent Organic Network Membranes.

Covalent organic networks (CONs) are considered ideal for precise molecular separation compared with traditional polymer membranes because their pores have a sharp molecular weight cut-off and a robust structure. However, challenges remain with regard to tuning pores as a prerequisite for facile membrane fabrication to a defect-free layer. Herein, a highly conjugated amino-porphyrin is used and exploited its tunable stacking behavior to fabricate porphyrin-based polyamide CONs with ordered structures through interfacial polymerization with acyl chlorides.

Influence of perfluoroalkyl substances, with focus on perfluorobutanoic acid on the responding characteristics and molecular mechanisms of Thalassiosira pseudonana.

Perfluoroalkyl substances (PFAS) are widely dispersed persistent organic pollutants (POPs) throughout marine ecosystems. Due to ban of traditional long-chain PFAS, the emerging short-chain ones showed increased environmental detection as substitutes. As the foundation of aquatic food webs, microalgae play a pivotal role in the stability of marine environments.

One-Step Phase Separation and Mineralization Fabrication of Membranes for Oily Wastewater Treatment.

Oily wastewater threatens the environment and the human health. Membrane technology offers a simple and efficient alternative to separating oil and water. However, complex membrane modifications are usually employed to optimize the separation performance.

Organo-photoredox catalyzed -difluoroallylation of ketone-derived dihydroquinazolinones C(sp)-C bond and C(sp)-F bond cleavage.

An organo-photoredox catalyzed -difluoroallylation of both acyclic and cyclic ketone derivatives with α-trifluoromethyl alkenes has been demonstrated, thus giving access to a diverse set of -difluoroalkenes in moderate to high yields. Pro-aromatic dihydroquinazolinones can be either pre-formed or generated for ketone activation. This reaction is characterized by readily available starting materials, mild reaction conditions, and broad substrate scope.

A enzyme-free fluorescence quenching sensor for amplified detection of kanamycin in milk based on competitive triggering strategies.

In this work, we constructed a FAM fluorescence quenching biosensor based on an aptamer competition recognition and enzyme-free amplification strategy. We design a competing unit consisting of an aptamer chain and a complementary chain, and a catalytic hairpin self-assembly (CHA) unit consisting of two hairpins in which the complementary chain can trigger the catalytic hairpin self-assembly. In the initial state, the aptamer chain is combined with the complementary chain, the catalytic hairpin self-assembly unit is inhibited, the FAM fluorescence group was far away from the BHQ1 quenching group, and the fluorescence is turn-on.

A label free fluorescent aptamer sensor based on the combined action of Graphene oxide and SYBR Green I for the detection of Aflatoxin B1.

Here, based on the characteristics of Graphene oxide(GO) and SYBR Green I(SGI) dye, an enzyme-free and label-free fluorescent biosensor with signal amplification through DNA strand reaction is proposed for the detection of Aflatoxin B1(AFB1) in food safety. Firstly, without the addition of AFB1, the substrate in the system includes a double stranded Apt-S with a long sticky end and two hairpins H1 and H2. Although the complementary pairing of bases may exhibit fluorescence due to the insertion of SGI dyes, the use of GO, which is highly capable of adsorbing single stranded parts and quenching fluorescence, cleverly reduces the background fluorescence.

Fabrication of polydopamine/rGO Membranes for Effective Radionuclide Removal.

In this work, a novel polydopamine/reduced graphene oxide (PDA/rGO) nanofiltration membrane was prepared to efficiently and stably remove radioactive strontium ions under an alkaline environment. Through the incorporation of PDA and thermal reduction treatment, not only has the interlayer spacing of graphene oxide (GO) nanosheets been appropriately regulated but also an improved antiswelling property has been achieved. The dosage of GO, reaction time with PDA, mass ratio of PDA to GO, and thermal treatment temperature have been optimized to achieve a high-performance PDA/rGO membrane.

Iron-Catalyzed Allylic C(sp)-H Silylation: Spin-Crossover-Efficiency-Determined Chemoselectivity.

The nuanced role of spin effects remains a critical gap in designing proficient open-shell catalysts. This study elucidates an iron-catalyzed allylic C(sp)-H silylation/alkyne hydrosilylation reaction, in which the spin state of the open-shell iron catalyst dictates the reaction kinetics and pathway. Specifically, spin crossover led to alkyne hydrosilylation, whereas spin conservation resulted in a novel allylic C(sp)-H silylation reaction.

Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation.

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program.

Efficacy in bowel movement and change of gut microbiota on adult functional constipation patients treated with probiotics-containing products: a systematic review and meta-analysis.

Objectives: This study aimed to pool the efficacy in bowel movement and explore the change of gut microbiota on adult functional constipated patients after probiotics-containing products treatment.

Design: Systematic review and meta-analysis.

Data Sources: PubMed, Cochrane Library for published studies and ClinicalTrials.

Iron-Catalyzed Stereoconvergent 1,4-Hydrosilylation of Conjugated Dienes.

Stereoconvergent transformation of E/Z mixtures of olefins to products with a single steric configuration is of great practical importance but hard to achieve. Herein, we report an iron-catalyzed stereoconvergent 1,4-hydrosilylation reactions of E/Z mixtures of readily available conjugated dienes for the synthesis of Z-allylsilanes with high regioselectivity and exclusive stereoselectivity. Mechanistic studies suggest that the reactions most likely proceed through a two-electron redox mechanism.

Development and analysis of a universal label-free micro/nano component for three-channel detection of silver ions, mercury ions, and tetracycline.

In this paper, an enzyme-free and label-free fluorescent nanomodule is proposed for rapid, simple and sensitive detection of Ag, Hg and tetracycline (TC). The strategy is cleverly designed to enable multiple-purpose detection with as little as 31 nt of ssDNA. Both the embedded dye SYBR Green I and the nanomaterial graphene oxide (GO) are able to distinguish single-stranded DNA from double-stranded DNA; thus, the combination of the two instead of using traditional molecular beacon (MB)-labeled fluorophores and quencher groups can effectively reduce the cost of experiments while efficiently reducing the background noise.

Iron-Catalyzed Alkene Hydroalumination.

Hydroalumination of olefins generally gives thermodynamically controlled anti-Markovnikov addition selectivity in literatures. In this paper, a highly Markovnikov hydroalumination of aromatic terminal alkenes was realized to prepare various new benzylaluminum complexes by using the well-defined 2,9-diaryl-1,10-phenanthroline modified iron complex as the catalyst and commercially available DIBAL-H as the aluminum hydride reagent. This is the first ironcatalyzed alkene hydroalumination, and the regioselectivity observed in this study is different from the related reactions reported in the literatures.

Side-Chain-Dependent Functional Intercalations in Graphene Oxide Membranes for Selective Water and Ion Transport.

Subnanometer interlayer space in graphene oxide (GO) laminates is desirable for use as permselective membrane nanochannels. Although the facile modification of the local structure of GO enables various nanochannel functionalizations, precisely controlling nanochannel space is still a challenge, and the roles of confined nanochannel chemistry in selective water/ion separation have not been clearly defined. In this study, macrocyclic molecules with consistent basal plane but varying side groups were used to conjunct with GO for modified nanochannels in laminates.

Potential Universal Engineering Component: Tetracycline Response Nanoswitch Based on Triple Helix-Graphene Oxide.

The overuse of antibiotics can lead to the emergence of drug resistance, preventing many common diseases from being effectively treated. Therefore, based on the special composite platform of P1/graphene oxide (GO) and DNA triple helix, a programmable DNA nanoswitch for the quantitative detection of tetracycline (TC) was designed. The introduction of GO as a quenching agent can effectively reduce the background fluorescence; stabilizing the trigger strand with a triplex structure minimizes errors.

Developing a DNA logic gate nanosensing platform for the detection of acetamiprid.

This paper reports a novel fluorescence and colorimetric dual-signal-output DNA aptamer based sensor for the detection of acetamiprid residue. Acetamiprid is a new systemic broad-spectrum insecticide with high insecticidal efficiency that is widely used worldwide, but there is a risk of adverse neurological reactions in humans and animals. The dual-mode output principle designed in this paper, consisting of a fluorescence signal and colorimetric signal, is based on the relevant reaction of the special domain of a G-quadruplex, bidding farewell to a classical single-signal output, with a target-recognition cycle used to complete signal amplification through a hybridization chain reaction.

Iron-catalysed hydroalumination of internal alkynes.

Although research on iron-catalysed reactions has recently achieved significant progress, the activity and selectivity of iron catalysts are generally inferior to those of noble-metal catalysts. The development of new iron-catalysed reactions, especially those in which iron catalysts exhibit superior activity or selectivity to other catalysts, is the key to promote iron catalysis. Herein, we report the first protocol for iron-catalysed hydroalumination of internal alkynes.

Phenanthroline-imine ligands for iron-catalyzed alkene hydrosilylation.

Iron-catalyzed organic reactions have been attracting increasing research interest but still have serious limitations on activity, selectivity, functional group tolerance, and stability relative to those of precious metal catalysts. Progress in this area will require two key developments: new ligands that can impart new reactivity to iron catalysts and elucidation of the mechanisms of iron catalysis. Herein, we report the development of novel 2-imino-9-aryl-1,10-phenanthrolinyl iron complexes that catalyze both -Markovnikov hydrosilylation of terminal alkenes and 1,2--Markovnikov hydrosilylation of various conjugated dienes.

A Biosensor Based on Interchain Reactions for the Detection of Acetamiprid and the Construction of Basic Logic Gates OR and AND.

An enzyme-free and label-free fluorescent DNA aptasensor was constructed with computer assistance based on thermodynamic deviation driving interchain reactions. In this work, in the presence of target acetamiprid, the released trigger strand C-apt could open hairpin Hp1, which in turn triggered the strand displacement reaction and catalyzed the self-assembly of hairpins Hp1 and Hp2, so that the guanine base rich stem in Hp2 was opened. In the presence of K and NMM, the G-rich moiety could form a G-quadruplex and emit strong fluorescence at a specific excitation wavelength.

Iron-Catalyzed Vinylzincation of Terminal Alkynes.

Organozinc reagents are among the most commonly used organometallic reagents in modern synthetic chemistry, and multifunctionalized organozinc reagents can be synthesized from structurally simple, readily available ones by means of alkyne carbozincation. However, this method suffers from poor tolerance for terminal alkynes, and transformation of the newly introduced organic groups is difficult, which limits its applications. Herein, we report a method for vinylzincation of terminal alkynes catalyzed by newly developed iron catalysts bearing 1,10-phenanthroline-imine ligands.

Developing a three-input cascade DNA logic gate based on the biological characteristics of metal ion-GO, combined with analysis and verification.

Due to the limitation of technology, electronic computing is approaching the limit of technology, and new computing tools need to be developed. Here, we build a three-input cascade logic gate based on the advantages of biomolecules, particularly DNA, in the construction of computational logic systems, combined with metal ions and graphene oxide (GO). It is worth mentioning that this study uses a variety of research methods.

Transcriptomic analysis provides insights into the AUXIN RESPONSE FACTOR 6-mediated repression of nicotine biosynthesis in tobacco (Nicotiana tabacum L.).

NtARF6 overexpression represses nicotine biosynthesis in tobacco. Transcriptome analysis suggests that NtARF6 acts as a regulatory hub that connect different phytohormone signaling pathways to antagonize the jasmonic acid-induced nicotine biosynthesis. Plant specialized metabolic pathways are regulated by a plethora of molecular regulators that form complex networks.

Enantioselective Silicon-Directed Nazarov Cyclization.

The Nazarov electrocyclization reaction is a convenient, widely used method for construction of cyclopentenones. In the past few decades, catalytic asymmetric versions of the reaction have been extensively studied, but the strategies used to control the position of the double bond limit the substituent pattern of the products and thus the synthetic applications of the reaction. Herein, we report highly enantioselective silicon-directed Nazarov reactions which were cooperatively catalyzed by a Lewis acid and a chiral Brønsted acid.