A series of pyridine-type ligands containing CC bonds were designed and synthesized for selective oxidative Heck reaction. These ligands were utilized as functional units and integrated into the ...skeleton of conjugated microporous polymers. 6,6′-diiodo-2,2′-bipyridine and 1,3,5-triethynylbenzene were polycondensed via Sonogashira cross-coupling strategy to afford CMP-1 material. The resultant CMP-1 was used as a heterogeneous catalytic ligand for the PdII-catalyzed oxidative Heck reaction with high linear selectivity. The linear selectivity of CMP-1 is about 30 times higher than that of bipyridine-based monomer ligand. This work opens a new front of using CMP as an intriguing platform for developing highly efficient catalysts in controlling the regioselectivity in organic reactions.
Reactive oxygen species (ROS) have emerged as important cellular-signaling agents for cellular survival. Herein, we demonstrate that ROS-mediated oxidation of DNA to yield 8-oxo-7,8-dihydroguanine ...(OG) in gene promoters is a signaling agent for gene activation. Enhanced gene expression occurs when OG is formed in guanine-rich, potential G-quadruplex–forming sequences (PQS) in promoter-coding strands, initiating base excision repair (BER) by 8-oxoguanine DNA glycosylase (OGG1), yielding an abasic site (AP). The AP enables melting of the duplex to unmask the PQS, adopting a G-quadruplex fold in which apurinic/apyrimidinic endonuclease 1 (APE1) binds, but inefficiently cleaves, the AP for activation of vascular endothelial growth factor (VEGF) or endonuclease III-like protein 1 (NTHL1) genes. These details were mapped via synthesis of OG and AP analogs at single-nucleotide precision within the promoter of a luciferase reporter system. The reporters were analyzed in human and mouse cells while selectively knocking out or down critical BER proteins to identify the impact on luciferase expression. Identification of the oxidatively modified DNA base OG to guide BER activity in a gene promoter and impact cellular phenotype ascribes an epigenetic role to OG.
The catalytic conversion of ethanol into butanol is one of crucial reactions in biorefinery for the production of renewable fuels and chemicals. The development of highly durable non‐noble ...metal‐based catalysts is of great significance but poses big challenges. Herein, we prepared a series of NiAl‐hydrotalcite derived Cu/NiAlOx catalysts via the hydrothermal precipitation method. Cu addition to the system shows an enhanced reactivity in the continuous catalytic conversion of ethanol into butanol. The 0.75 %Cu/NiAlOx catalyst afford a sustained ethanol conversion of ∼35 % and butanol selectivity of ∼45 % within 1000 h at 250 °C, 3 MPa N2. Complementary characterization studies reveal that Cu addition into the catalysts could not only provide redox sites for facilitating the dehydrogenation/hydrogenation processes, but also modulate the base/acid property for suppressing the side reactions. The excellent stability might stem from the enhanced interaction between Cu and Ni species, as evidenced by EDX‐mapping and H2‐TPR. We believe this work will help to rational design and develop of high‐performing and durable non‐noble metal catalysts for ethanol coupling to higher alcohols.
Acid‐base catalysis: High performing and stable Cu/NiAlOx catalysts were developed for continuous catalytic conversion of ethanol into butanol, with sustained ethanol conversion of ∼35 % and butanol selectivity of ∼45 % for 1000 h. The induced strong interaction between Cu and Ni species under the redox conditions could prevent the agglomeration of Cu species and maintain the long‐term stability in the catalysis.
Heterogeneous, metal, single‐site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a ...precoordination/solvothermal polymerization strategy to fabricate a stable mononuclear Pd‐metalized porous organic polymer catalyst (Pd@POP). Pd@POP was easy to use in regioselective organic reactions because the internal structure of this Pd@POP can be easily modified. The catalyst was used to solve the intractable regioselectivity problems of Heck reactions. Pd@POP‐9 can efficiently activate the ends of olefins, thereby leading to high selectivity for substitution at the external position. To understand the reason underlying the high selectivity and activity of the catalyst, the systemic characterization of Pd@POP‐9 and density‐functional theory calculations were conducted. This Heck reaction is the first to be catalyzed by a recyclable mononuclear metal catalyst with unprecedented catalytic activity and regioselectivity.
Pop around: Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stable atomically dispersed mononuclear Pd‐metalized N‐heterocyclic carbene doped porous organic polymer catalyst (Pd@POP). This Heck reaction of electronically unbiased alkenes is the first to be catalyzed by a recyclable catalyst (Pd@POP‐9) with unprecedented catalytic activity and regioselectivity.
To investigate the effect of long non-coding RNA LINC01268 on apoptosis of acute myeloid leukemia (AML) cells and related mechanisms.
The expression levels of LINC01268 and miR-217 in peripheral ...blood samples from AML patients and AML cell lines HL-60 and KG-1 were detected by qRT-PCR. HL-60 cells were divided into pcDNA3.1-NC, pcDNA3.1-LINC01268, si-NC, si-LINC01268, miR-NC, miR-217 mimics, si-LINC01268 + inhibitor-NC and si-LINC01268+ miR-217 inhibitor groups. The mRNA expressions of LINC01268 and miR-217 were detected by qRT-PCR. The targeting relationship between LINC01268 and miR-217 was detected by dual-luciferase reporter assay. Cell viability was detected by CCK-8 assay. Cell cycle distribution and apoptosis were detected by flow cytometry. The expression of cell cycle and apoptosis-related proteins p21, Bcl-2, Bax, caspase-3 and PI3K/AKT signaling pathway-related proteins were detected by Western blot.
The expression of LINC01268 in peripheral blood samples of AML patients and AML cell lines HL-60 an
A new type of phosphorus‐doped porous organic polymer (POP) has been readily synthesized through a Heck reaction, which could be used not only as a support but also a ligand for palladium ...nanoparticles. The dual‐functional material supported palladium nanocatalyst was used for the efficient and chemoselective hydrogenation of varieties of nitroarenes and α,β‐unsaturated compounds, as well as for the synthesis of indoles from 2‐nitrophenylacetonitrile under 1 atm hydrogen in green solvents at room temperature. No obvious aggregation and loss of catalytic activity of the new nanocatalyst were observed after 10 runs in the reaction.
There is insufficient evidence on the efficacy of masks in the general population for the prevention of coronavirus disease 2019 (COVID-19) in public areas. Therefore, it is imperative to investigate ...the association of mandatory mask-wearing policies with behaviors associated with the transmission of COVID-19.
To assess the association of mask wearing with face-touching behavior among the general population in public areas.
This cross-sectional study used videos recorded in public transportation stations, streets, and parks among the general population in China, Japan, South Korea, Western Europe (ie, England, France, Germany, Spain, and Italy), and the US to analyze mask-wearing and face-touching behavior in public areas. Videos before the COVID-19 pandemic were defined as those recorded from January 2018 to October 2019, and those during the COVID-19 pandemic were defined as those recorded during February 2020 to March 2020 in China, Japan, and South Korea and during March 2020 in Western Europe and the US. Individuals who clearly displayed their face and face-touching behavior were included, and those whose behaviors were influenced by filming or public events were excluded.
Mandatory mask-wearing policies enacted at various time points in China, Japan, South Korea, Western Europe, and the US.
Proportion of individuals wearing masks and incidence of face touching.
This study included 4699 individuals before the COVID-19 pandemic and 2887 individuals during the pandemic. During the periods studied, mask wearing increased in all regions except the US, from 20 of 1745 individuals (1.1%) to 1090 of 1097 individuals (99.4%) in mainland China (P < .001), 44 of 1422 individuals (3.1%) to 346 of 893 individuals (38.7%) in Japan (P < .001), 6 of 717 individuals (0.8%) to 277 of 324 individuals (85.5% ) in South Korea (P < .001), 1 of 546 individuals (0.2%) to 6 of 379 individuals (1.6%) in Western Europe (P = .02), and 1 of 269 individuals (0.4%) to 4 of 194 individuals (2.1%) in the US (P = .17). Surgical masks were predominant in China (989 masks 89.1%), and fabric masks were predominant in the other regions (Japan: 371 masks 95.1%; South Korea: 240 masks 84.8%; Western Europe: 6 masks 85.7%; US: 5 masks 100%). Face-touching behaviors decreased from before COVID-19 to during COVID-19 among individuals in China (72 incidences of 1745 observations 4.1% to 12 incidences of 1097 observations 1.1%; P < .001), South Korea (80 incidences of 717 observations 11.2% to 7 incidences of 324 observations 2.2%; P < .001), and Europe (62 incidences of 546 observations 11.4% to 23 incidences of 379 observations 6.1%; P = .01). Logistic regression found that mask wearing was associated with a reduction in face touching in China (odds ratio OR, 3.91; 95% CI, 2.11-7.24) and South Korea (OR, 6.69; 95% CI, 2.69-16.69) and of touching the nose, mouth, and eyes (China: OR, 8.60; 95% CI, 2.65-27.86; South Korea: OR, 29.27; 95% CI, 1.79-478.22).
The findings of this cross-sectional study suggest that mandatory mask-wearing policies were associated with increased mask wearing during the COVID-19 pandemic. Mask wearing was associated with reduced face-touching behavior, especially touching of the eyes, nose, and mouth, which may prevent contact transmission of COVID-19 among the general population in public areas.
With the development of modern chemistry and biology, non-proteinogenic amino acids (NPAAs) have become a powerful tool for developing peptide-based drug candidates. Drug-like properties of peptidic ...medicines, due to the smaller size and simpler structure compared to large proteins, can be changed fundamentally by introducing NPAAs in its sequence. While peptides composed of natural amino acids can be used as drug candidates, the majority have shown to be less stable in biological conditions. The impact of NPAA incorporation can be extremely beneficial in improving the stability, potency, permeability, and bioavailability of peptide-based therapies. Conversely, undesired effects such as toxicity or immunogenicity should also be considered. The impact of NPAAs in the development of peptide-based therapeutics is reviewed in this article. Further, numerous examples of peptides containing NPAAs are presented to highlight the ongoing development in peptide-based therapeutics.
Radiotherapy is one important treatment for malignant tumours. It is widely believed today that radiotherapy has not only been used as a local tumour treatment method, but also can induce systemic ...anti-tumour responses by influencing the tumour microenvironment, but its efficacy is limited by the tumour immunosuppression microenvironment. With the advancement of technology, immunotherapy has entered a golden age of rapid development, gradually occupying a place in clinical tumour treatment. Regulatory T cells (Tregs) widely distributing in the tumour microenvironment play an important role in mediating tumour development. This article analyzes immunotherapy, the interaction between Tregs, tumours and radiotherapy. It briefly introduces immunotherapies targeting Tregs, aiming to provide new strategies for radiotherapy combined with Immunotherapy.
Oxidative damage to the genome can yield the base 8-oxo-7,8-dihydroguanine (OG). In vitro studies suggested OG would preferentially form in 5′-GG-3′ sequence contexts after exposure to reactive ...oxygen species. Herein, OG locations in the genome were studied by development of “OG-Seq” to sequence OG sites via next-generation sequencing at ∼0.15-kb resolution. The results of this study found ∼10 000 regions of OG enrichment in WT mouse embryonic fibroblasts and ∼18 000 regions when the OG repair glycosylase Ogg1 was knocked out. Gene promoters and UTRs harbor more OG-enriched sites than expected if the sites were randomly distributed throughout the genome and correlate with reactive 5′-GG-3′ sequences, a result supporting decades of in vitro studies. Sequencing of OG paves the way to address chemical and biological questions surrounding this modified DNA base, such as its role in disease-specific mutations and its epigenetic potential in gene regulation.
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