Effect of Al/Si Substitutions and Silanol Nests on the Local Geometry of Si and Al Framework Sites in Silicone-Rich Zeolites: A Combined High Resolution ²⁷Al and ²⁹Si NMR and Density Functional Theory/Molecular Mechanics Study

We employed 29Si and 27Al (3Q) magic-angle spinning (MAS) NMR spectroscopy and density functional theory/molecular mechanics (DFT/MM) calculations to investigate the effect of Al/Si substitutions and the presence of silanol nests on the 29Si and 27Al NMR parameters as well as the local geometry of SiO4 and AlO4− tetrahedra of the nearest and next-nearest neighboring Si and Al atoms. The silicon-rich zeolite of the chabazite structure (Si/Al 38) was chosen for this study as a representative model of silicon-rich zeolites since it exhibits a low number of distinguishable T sites. Our computational results show the following: (I) Al atoms can occupy three different crystallographic T sites in the framework of chabazite (Si/Al 38). This result is in agreement with two observed 27Al NMR resonances. (II) An Al/Si substitution causes a downshift of the 29Si chemical shift of the nearest neighboring Si atoms (Al−O−Si) by 4−11 ppm. (III) The effect of a more distant Al/Si substitution (Al−O−Si−O−Si) is significantly less pronounced (downshift up to 2 ppm). (IV) An Al/Si substitution (Al−O−Si−O−Al) leads to larger 27Al isotropic chemical shifts of the next-nearest neighboring Al atoms by up to 3 ppm. (V) The presence of a silanol “nest” (vacant T site) as a nearest (H−O−Si) and next-nearest (H−O−Si−O−Si) neighbor is responsible for a systematic downshift of the 29Si chemical shift of Si by 11−16 ppm and by 0−1 ppm, respectively. (VI) There is no systematic effect of a silanol “nest” as a next-nearest neighbor (H−O−Si−O−Al) on the 27Al isotropic chemical shift of Al as its values are smaller for some H−O−Si−O−Al sequences (up to −3.6 ppm) and greater for others (up to +2.9 ppm). (VII) Al atoms present in hypothetical Al−O−Al sequences would have their 27Al isotropic chemical shifts larger by 7−9 ppm than single Al atoms. Our predictions of NMR parameters using the quantum mechanics/interatomic potential functions approach and our bare zeolite framework model are in good agreement with the available experiments

Proton-Coupled Electron Transfer of Plastoquinone Redox Reactions in Photosystem II: A Pump–Probe Ultraviolet Resonance Raman Study

Plastoquinones (PQs) act as electron and proton mediators in photosystem II (PSII) for solar-to-chemical energy conversion. It is known that the redox potential of PQ varies in a wide range spanning hundreds of millivolts; however, its structural origin is not known yet. Here, by developing a pump–probe ultraviolet resonance Raman technique, we measured the vibrational structures of PQs including QA and QB in cyanobacterial PSII directly. The conversion of QA to QA•– in the Mn-depleted PSII is verified by direct observation of the distinct QA•– vibrational bands. A frequency upshift of the ring C=O/C=C stretch band at 1565 cm–1 for QA•– was observed, which suggests a π–π interaction between the quinone ring and Trp253. In contrast, proton-coupled reduction of QA to QAH upon light-driven electron transfer is demonstrated in PSII without QB bound. The H-bond between QA and His214 is likely the proton origin of this proton-coupled electron transfer

Proton-Coupled Electron Transfer of Plastoquinone Redox Reactions in Photosystem II: A Pump–Probe Ultraviolet Resonance Raman Study

Plastoquinones (PQs) act as electron and proton mediators in photosystem II (PSII) for solar-to-chemical energy conversion. It is known that the redox potential of PQ varies in a wide range spanning hundreds of millivolts; however, its structural origin is not known yet. Here, by developing a pump–probe ultraviolet resonance Raman technique, we measured the vibrational structures of PQs including QA and QB in cyanobacterial PSII directly. The conversion of QA to QA•– in the Mn-depleted PSII is verified by direct observation of the distinct QA•– vibrational bands. A frequency upshift of the ring C=O/C=C stretch band at 1565 cm–1 for QA•– was observed, which suggests a π–π interaction between the quinone ring and Trp253. In contrast, proton-coupled reduction of QA to QAH upon light-driven electron transfer is demonstrated in PSII without QB bound. The H-bond between QA and His214 is likely the proton origin of this proton-coupled electron transfer

The effect of LSD1 inhibition on the hTERT mRNA expression or gene transcription in human normal fibroblast MRC5 cells.

<p>(A) The induction and synergistic up-regulation of hTERT mRNA expression in MRC5 cells by the LSD1 inhibitor tranylcypromine alone and its combined treatment with the histone deacetylase (HDAC) inhibitor TSA, respectively. The cells were incubated with either tranylcypromine at 25.0 µM or TSA 0.1 µM, or both of them overnight and then harvested for hTERT mRNA analyses using RT-PCR. Trans: tranylcypromine. (B) The synergistic effect of LSD1 and CoREST depletion on the induction of hTERT mRNA in MRC5 cells. The knocking-down of LSD1 and CoREST expression was performed using the specific siRNA targeting LSD1 and CoREST. Arrow: primer dimmers. (C) The demonstration of efficient down-regulation of the target genes in siRNA-transfected cells. Lane 1: Control siRNA; lane 2: LSD1 (Upper) and CoREST siRNAs (Lower), respectively; and lane 3: LSD1+CoREST siRNAs. Note the results in (B) and (C) were from the same set of cDNA, and therefore, β2 –M was only shown in (B). (D) The up-regulation of the hTERT promoter activity by tranylcypromine. The p181 reporter construct that harbors the hTERT proximal promoter sequence was transfected into MRC5 cells in the absence or presence of tranylcypromine, and then analysed for luciferase activity 48 hours later. Variation in transfection efficiency was normalized by the TK-driven <i>Renilla</i> luciferase activity. Columns: Relative luciferase activity arbitrarily expressed as the ratio of p181/TK; Bars: SD.</p

LSD1-depletion mediated up-regulation of hTERT and telomerase expression through enhancing H3-K4(M2) and H3 acetylation at the hTERT proximal promoter in cancer cells.

<p>(A) The up-regulation of hTERT mRNA expression induced by depletion of LSD1 in human cancer cells. RT-PCR for LSD1 mRNA was shown to verify efficient depletion of LSD1 expression in those cells. The lower panel further demonstrated an inhibition of LSD1 expression at protein levels in HeLa and SiHa cells treated with LSD1 siRNA. WB: Western blot. (B) The enhanced telomerase activity in HeLa and SiHa cells with LSD1 depletion. (C) The western blot analysis of global histone H3 acetylation, H3-K4, and H3-K9 mono-, di- and tri-methylation in HeLa and SiHa cells transfected with LSD1 specific siRNA. Pansus staining was shown for equal histone protein loads. (D) The abolishment of LSD1 concomitant with the increased H3-K4(M2) and H3 acetylation at the hTERT proximal promoter in LSD1-depleted HeLa and SiHa cells. Representative ChIP results were shown. C and L: Control and LSD1 siRNA, respectively.</p

The recruitment of LSD1 to the hTERT proximal promoter concomitant with repression of hTERT transcription in the differentiated HL60 cells.

<p>(A) The down-regulation of hTERT mRNA expression in HL60 cells undergoing terminal differentiation induced by DMSO treatment. (B) The presence of LSD1 concomitant with a loss of H3-K4(M2) at the hTERT proximal promoter region in differentiated but not undifferentiated HL60 cells. Control: Undifferentiated HL60 cells and DMSO: DMSO-induced differentiated HL60 cells.</p

The tranylcypromine-induced up-regulation of hTERT mRNA expression and telomerase activity accompanied by increase in H3-K4(M2) and H3 acetylation at the hTERT proximal promoter region in human cancer cells.

<p>(A) The dose-dependent up-regulation of hTERT mRNA expression in A549, HeLa, SiHa and SW756 cells treated with tranylcypromine. (B) Telomerase activity in the same sets of cells treated with tranylcypromine (Trans) at 100 µM (for A549, HeLa and SW756) or 50 µM (for SiHa) as in (A). Telomerase activity was assessed using a telomerase PCR ELISA kit and arbitrarily expressed as absorbance (OD450–OD690). Columns: Relative telomerase activity; Bars: SD. (C) The western blot analysis of global histone H3 acetylation, H3-K4, and H3-K9 mono-, di- and tri-methylation in HeLa and SiHa cells treated with tranylcypromine (Trans). Pansus staining was shown for equal histone protein loads. (D) The increased histone H3-K4(M2) and H3 acetylation at the hTERT proximal promoter in tranylcypromine-treated HeLa and SiHa cells. Representative ChIP results were shown.</p

Modulation of Hot Electrons via Interface Engineering of Au@ZnIn₂S₄/MXene for Efficient Photoelectrochemical Seawater Splitting under Visible Light

Interface engineering in hybrid plasmonic metal/semiconductor heterostructures is an efficient approach to enhance the catalytic performance of photocatalysts and photoelectrochemical cells in harvesting and converting sunlight, especially in the range of visible light. Plasmon-induced hot electron injection plays a crucial role in the transfer of plasmonic energy from a plasmonic metal to semiconductor in a plasmonic metal/semiconductor system. Herein, the efficient injection and utilization of hot electrons are achieved by fabrication of a Au@ZnIn2S4/Ti3C2 (Au@ZIS/Ti3C2) system, in which the core–shell Au@ZIS nanoparticles with well-defined interfaces are anchored on the 2D Ti3C2 surface. The core–shell Au@ZIS nanostructure is first constructed by a cation exchange reaction method. The well-defined interface of the Au core and ZIS shell optimizes the electron transfer pathway and greatly promotes the extraction of hot electrons from Au to ZIS. Furthermore, the electrons concentrated on ZIS can be further transferred to Ti3C2 owing to its excellent electron mobility and conductivity, leading to highly efficient separation and transfer of electrons through a two-step transfer process. The activities of photoelectrochemical (PEC) seawater splitting demonstrate that the integration of Au and ZIS into an optimized core–shell structure and its further modification by Ti3C2 results in a drastic improvement in PEC activity. Therefore, Au@ZIS/Ti3C2 shows the highest photocurrent density and smallest charge transfer resistance among various samples, accompanied by 6.5 and 10.8 orders of enhancement in PEC H2 evolution compared to reference samples of ZIS/Ti3C2 and Au/Ti3C2. Elaborate design and construction of core–shell plasmonic metal@semiconductor nanostructure with a well-defined interface and 2D MXene support would provide a feasible and promising method to enhance the performance of PEC seawater splitting

DataSheet1_To explore the effect of kaempferol on non-small cell lung cancer based on network pharmacology and molecular docking.pdf

Non-small cell lung cancer (NSCLC) is a common pathological type of lung cancer, which has a serious impact on human life, health, psychology and life. At present, chemotherapy, targeted therapy and other methods commonly used in clinic are prone to drug resistance and toxic side effects. Natural extracts of traditional Chinese medicine (TCM) have attracted wide attention in cancer treatment because of their small toxic and side effects. Kaempferol is a flavonoid from natural plants, which has been proved to have anticancer properties in many cancers such as lung cancer, but the exact molecular mechanism is still unclear. Therefore, on the basis of in vitro experiments, we used network pharmacology and molecular docking methods to study the potential mechanism of kaempferol in the treatment of non-small cell lung cancer. The target of kaempferol was obtained from the public database (PharmMapper, Swiss target prediction), and the target of non-small cell lung cancer was obtained from the disease database (Genecards and TTD). At the same time, we collected gene chips GSE32863 and GSE75037 in conjunction with GEO database to obtain differential genes. By drawing Venn diagram, we get the intersection target of kaempferol and NSCLC. Through enrichment analysis, PI3K/AKT is identified as the possible key signal pathway. PIK3R1, AKT1, EGFR and IGF1R were selected as key targets by topological analysis and molecular docking, and the four key genes were further verified by analyzing the gene and protein expression of key targets. These findings provide a direction for further research of kaempferol in the treatment of NSCLC.</p