Mild and Efficient Preparation of N-Heterocyclic Organic Molecules by Catalyst-free and Solvent-free Methods.

AIMS: The small organic molecular compounds with biological activity containing C-C and C-N or C-O bonding were efficiently prepared without catalyst and solvent in the hydrothermal synthesis reactor. OBJECTIVES: Our goal was to explore new applications for the more environmentally friendly and efficient synthesis of bis(indolyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives in hydrothermal synthesis reactors under solvent-free and catalyst-free conditions. METHODS: A greener and more efficient method was successfully developed for the synthesis of bis(indolyl)methyl, heteroanthracene, quinazolinone, and N-heterocyclic derivatives using a hydrothermal synthesis reactor in a solvent- and catalyst-free manner. RESULTS: In a hydrothermal synthesis reactor, bis(indoyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives were synthesized without catalysts and solvents. CONCLUSION: Overall, it is proved once again that the catalyst-free and solvent-free synthesis method has universal value and is a more ideal and environmentally friendly new method, especially the hydrothermal reactor for synthesis.

Acid protonation promoted different crystal phase structure silicon carbide-based carbon nitride composites to enhance the photocatalytic degradation of dye wastewater.

Acid-protonated crystalline silicon carbide-supported carbon nitride photocatalytic composites were successfully prepared by the impregnation-heat treatment method (P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), UV-vis diffuse reflectance spectra (UV-vis-DRS) photoluminescence (PL), etc. The results of SEM showed that the P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC materials were transformed from large-area lamellar structures to uniform and dispersed lamellar particles. The UV-vis-DRS and PL showed that the recombination probability of photogenerated electron-hole pairs of P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC samples decreased and the band gap increased. The results of photocatalytic degradation of alizarin red S (ARS), acid fuchsin (AF), and basic fuchsin (BF) showed that the samples P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC had excellent photocatalytic degradation performance. It is worth noting that the degradation performance of the sample P-g-C3N4/ß-SiC on the three dyes is better than that of P-g-C3N4/α-SiC. The electron spin resonance spectra (ESR) results showed that the ˙O2- and ˙OH produced by the two catalysts during the dye degradation process played a leading role in the degradation reaction. Fortunately, the catalyst maintains an excellent cycle life and can be reused more than seven times while degrading all three dyes.

A κ-Carrageenan-Containing Organohydrogel with Adjustable Transmittance for an Antifreezing, Nondrying, and Solvent-Resistant Strain Sensor.

Gel polymers are widely used in different fields due to their unique properties, especially in flexible electronic devices. However, developing multienvironmentally-tolerant (antifreezing, antidrying, and solvent-resistant) gel polymer-based soft electronics is still a significant challenge. Herein, a binary solvent system-based versatile organohydrogel is designed and successfully prepared, which exhibits superior stretchability, favorable self-adhesive properties, prominent temperature tolerance, and excellent solvent-resistant capabilities. Furthermore, the as-assembled organohydrogel-based sensor demonstrates a satisfied sensitivity (GF = 1.8), wide strain range (5-500%), and outstanding human motion detection. Meanwhile, the obtained organohydrogel can also serve as an all-weather sensor for achieving precise and reliable mechanical sensing in a wide temperature range from -50 to 50 °C and diverse liquid media consisting of water, toluene, and carbon tetrachloride. Interestingly, the organohydrogel displays a repeatable transmittance change behavior in water and dimethyl sulfoxide, based on this feature, which could realize the functional applications for recording and erasing information. It is envisioned that these superior performances render the as-prepared organohydrogel suitable to develop future advanced soft electronics with multienvironmental tolerance.

Prediction of Transcription Factor Binding Sites Using a Combined Deep Learning Approach.

In the process of regulating gene expression and evolution, such as DNA replication and mRNA transcription, the binding of transcription factors (TFs) to TF binding sites (TFBS) plays a vital role. Precisely modeling the specificity of genes and searching for TFBS are helpful to explore the mechanism of cell expression. In recent years, computational and deep learning methods searching for TFBS have become an active field of research. However, existing methods generally cannot meet high performance and interpretability simultaneously. Here, we develop an accurate and interpretable attention-based hybrid approach, DeepARC, that combines a convolutional neural network (CNN) and recurrent neural network (RNN) to predict TFBS. DeepARC employs a positional embedding method to extract the hidden embedding from DNA sequences, including the positional information from OneHot encoding and the distributed embedding from DNA2Vec. DeepARC feeds the positional embedding of the DNA sequence into a CNN-BiLSTM-Attention-based framework to complete the task of finding the motif. Taking advantage of the attention mechanism, DeepARC can gain greater access to valuable information about the motif and bring interpretability to the work of searching for motifs through the attention weight graph. Moreover, DeepARC achieves promising performances with an average area under the receiver operating characteristic curve (AUC) score of 0.908 on five cell lines (A549, GM12878, Hep-G2, H1-hESC, and Hela) in the benchmark dataset. We also compare the positional embedding with OneHot and DNA2Vec and gain a competitive advantage.

Boosting Room Temperature Sensing Performances by Atomically Dispersed Pd Stabilized via Surface Coordination.

The urgent requirement of monitoring air pollution worldwide evokes intensive research interest in developing chemiresistive gas sensing techniques. To overcome the limits in sensitivity and selectivity of room temperature (RT) chemiresistive sensing materials, a new strategy using single-atom catalysts (SACs) via surface coordination is proposed. As a proof-of-concept, single Pd atoms on TiO2 (Pd1-TiO2) possess high efficiency in generating adsorbed O2- as well as high activity and selectivity in catalyzing CO oxidation at RT. As a result, Pd1-TiO2 shows record high sensitivity among the reported RT sensing materials, which is even comparable to those of the best materials working at high temperature. It also provides an approximately 1 order of magnitude lower limit of detection than the best CO sensing materials. Moreover, Pd1-TiO2 presents high selectivity toward 12 kinds of interference gases. This work not only paves a way to design high-performance RT gas sensing materials but also extends the application of SACs.

Comparative genomic analysis of different virulence strains reveals reasons for the increased virulence of Aeromonas veronii.

Aeromonas veronii is an important zoonotic and aquatic agent. More and more cases have shown that it has caused huge economic losses in the aquaculture industry in addition to threatening human health. But the reasons for the increasing virulence of A. veronii are still unclear. In order to further understand the reasons for the increased virulence of A. veronii, we conducted a comparative analysis of the genomes of A. veronii with different virulence. The analysis revealed that there are multiple virulence factors, such as those related to fimbriae, flagella, toxins, iron ion uptake systems and type II, type III and type VI secretion systems in the virulent strain TH0426 genome. And comparative analysis showed that there were two complete type III secretion systems (API1 and API2), of which the API2 and iron ion transport system were unique to the TH0426 strain. In addition, TH0426 strain also has unique functional gene clusters, which may play important roles in terms of resisting infection, adapting to different environments and genetic evolution. These particular virulence factors and gene clusters may be the important reasons for the increased virulence. These insights will provide a reference for the study of the pathogenesis of A. veronii.

Comparative proteomic analysis reveals novel potential virulence factors of Aeromonas veronii.

Aeromonas veronii is an important zoonotic and aquatic pathogen. An increasing number of reports indicate that it has caused substantial economic losses in the aquaculture industry, in addition to threatening human health. However, little is known about its pathogenesis. Exploration of new virulence factors of A. veronii would be helpful for further understanding its pathogenesis. Hence, we comparatively analyzed the proteomes of virulent, attenuated, and avirulent strains of A. veronii using tandem mass tag (TMT) protein labeling and found numerous proteins either up- or downregulated in the virulent strain. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that these differentially expressed proteins (DEPs) were involved mainly in pathways associated with bacterial chemotaxis and microbial metabolism in diverse environments. Furthermore, the expression levels of lysine decarboxylase, endoribonuclease, maltoporin, pullulanase, and aerolysin were positively correlated with the virulence of the strains, suggesting that their function may be closely related to the virulence of A. veronii. The results of qRT-PCR and multiple reaction monitoring for some DEPs were consistent with the results of TMT protein labeling. These results suggest that these DEPs may be novel potential virulence factors and will help to further understand the pathogenesis of A. veronii.

Organic "receptor" fully covered few-layer organic-metal chalcogenides for high-performance chemiresistive gas sensing at room temperature.

Organic-metal chalcogenides (OMCs) are proposed as a new family of two-dimensional (2D) chemiresistive sensing materials. Few-layer Ag(SPh-NH2), one of the OMCs, fully and orderly covered with predesigned -NH2 groups as "receptors", shows the highest sensitivity, excellent selectivity and reversibility in response to NO2 among all the reported 2D chemiresistive sensing materials at room temperature.

Van der Waals Heterostructured MOF-on-MOF Thin Films: Cascading Functionality to Realize Advanced Chemiresistive Sensing.

Heterostructured metal-organic framework (MOF)-on-MOF thin films have the potential to cascade the various properties of different MOF layers in a sequence to produce functions that cannot be achieved by single MOF layers. An integration method that relies on van der Waals interactions, and which overcomes the lattice-matching limits of reported methods, has been developed. The method deposits molecular sieving Cu-TCPP (TCPP=5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) layers onto semiconductive Cu-HHTP (HHTP=2,3,6,7,10,11-hexahydrotriphenylene) layers to obtain highly oriented MOF-on-MOF thin films. For the first time, the properties in different MOF layers were cascaded in sequence to synergistically produce an enhanced device function. Cu-TCPP-on-Cu-HHTP demonstrated excellent selectivity and the highest response to benzene of the reported recoverable chemiresistive sensing materials that are active at room temperature. This method allows integration of MOFs with cascading properties into advanced functional materials.