| 1. |
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| 2. |
- Wang, Dongping, et al.
(författare)
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Asymmetric epoxidation of styrene and chromenes catalysed by dimeric chiral (pyrrolidine salen)Mn(III) complexes
- 2006
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Ingår i: Applied Catalysis A. - : Elsevier BV. - 0926-860X .- 1873-3875. ; 315, s. 120-127
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Tidskriftsartikel (refereegranskat)abstract
- Two dimeric chiral (pyrrolidine salen)Mn(III) complexes 3 and 4 were prepared, in which the two (pyrrolidine salen)Mn(III) units are linked either by a p-xylylene or by ap-phthalyl bridge. High yields were attained for asymmetric epoxidation of styrene and substituted chromenes at 0.5-4.0 mol% catalyst loading of 3 and 4 using NaClO/PPNO and m-CPBA/NMO as oxidant systems, with 37-39% ee for styrene and 86-95% ee for substituted chromenes. Dimeric complexes 3 and 4 displayed higher activities than their parent monomeric complexes 1 and 2 of double equiv for epoxidation of substituted chromenes. Complex 3 bearing two tertiary amine units displayed considerably higher activity than analogous dimeric complex 4 containing two carboxamide units in the aforementioned reaction. The effect of excess CH3I on the epoxidation of 6-nitro-2,2-dimethylchromene catalysed by 3 in the aqueous/organic biphasic medium was explored. The recovery and recycling possibilities of the dimeric complexes 3 and 4 were studied.
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| 3. |
- Gao, Aiping, et al.
(författare)
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Asymmetric oxidation of sulfides catalyzed by chiral (salen)Mn(III) complexes with a pyrrolidine backbone
- 2006
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Ingår i: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 20:12, s. 830-834
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Tidskriftsartikel (refereegranskat)abstract
- Catalytic properties of a series of chiral (pyrrolidine salen)Mn(III) complexes for asymmetric oxidation of aryl methyl sulfides were evaluated. Moderate activity, good chemical selectivity and low enantioselectivity were attained with iodosylbenzene as a terminal oxidant. Enantioselectivity of sulfide oxidation was affected slightly by polar solvent and the sulfoxidation carried out in THF for thioanisole and in CH3CO2Et for electron-deficient sulfides gave better enatioselctivities. The addition of the donor ligand PPNO (4-phenylpyridine N-oxide) or MNO (trimethylamine N-oxide) only has a minor positive effect on the enantioselectivity. Also explored was the steric effect of the N-aza-substituent in the backbone of (pyrrolidine salen)Mn(III) complexes on the enantioselectivity of sulfide oxidation. The sulfides' access pathway is discussed based on the catalytic results.
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| 4. |
- Gao, Aiping, et al.
(författare)
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Asymmetric oxidation of sulfides catalyzed by vanadium(IV) complexes of dibromo- and diiodo-functionalized chiral Schiff bases
- 2006
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Ingår i: Cuihuà xuébào. - 0253-9837 .- 1872-2067. ; 27:8, s. 743-748
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Tidskriftsartikel (refereegranskat)abstract
- The catalyst system of VO(acac)(2) and Schiff base ligands derived from 3,5-dibromo- or 3,5-diiodosalicylaldehyde and inexpensive chiral amino alcohols was prepared. This catalyst displayed good yields and moderate to high enantioselectivity for the asymmetric oxidation of aryl methyl sulfides at room temperature when 1% catalyst (VO(acac)(2)/ligand molar ratio of 1: 2) and H2O2 Oxidant were used. The ligands derived from ( S)valinol exhibited considerably higher enantioselectivity than those ligands derived from ( S)-phenylalaninol and (R)-leucinol. The enantiomeric excess values were improved up to 88% for methyl phenyl sulfoxide and 92% for methyl p-bromophenyl sulfoxide by slow dropwise addition of H2O2 with the ligand prepared from 3 15-diiodosalicylaldehyde and (s)-valinol. The present study showed that the catalytic efficiency of VO(acac)(2) /Schiff base systems could not be improved by the addition of carboxylic acids or carboxylate salts.
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| 5. |
- Wang, Fei, et al.
(författare)
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Endothelial cell heterogeneity and microglia regulons revealed by a pig cell landscape at single-cell level
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Pigs are valuable large animal models for biomedical and genetic research, but insights into the tissue- and cell-type-specific transcriptome and heterogeneity remain limited. By leveraging single-cell RNA sequencing, we generate a multiple-organ single-cell transcriptomic map containing over 200,000 pig cells from 20 tissues/organs. We comprehensively characterize the heterogeneity of cells in tissues and identify 234 cell clusters, representing 58 major cell types. In-depth integrative analysis of endothelial cells reveals a high degree of heterogeneity. We identify several functionally distinct endothelial cell phenotypes, including an endothelial to mesenchymal transition subtype in adipose tissues. Intercellular communication analysis predicts tissue- and cell type-specific crosstalk between endothelial cells and other cell types through the VEGF, PDGF, TGF-beta, and BMP pathways. Regulon analysis of single-cell transcriptome of microglia in pig and 12 other species further identifies MEF2C as an evolutionally conserved regulon in the microglia. Our work describes the landscape of single-cell transcriptomes within diverse pig organs and identifies the heterogeneity of endothelial cells and evolutionally conserved regulon in microglia.
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| 6. |
- Andersson, Maria, et al.
(författare)
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Inhibition of kainic acid binding to glutamate receptors by extracts of Gastrodia
- 1995
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Ingår i: Phytochemistry. - 0031-9422. ; 38:4, s. 835-836
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Tidskriftsartikel (refereegranskat)abstract
- S-(4-hydroxybenzyl)glutathione was isolated as the major principle responsible for the inhibition of the in vitro binding of kainic acid to brain glutamate receptors by water extracts of the plant Gastrodia elata. The affinity (IC50 value) of the compound is slightly lower compared to glutamate and glutathione.
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| 7. |
- Hellenbrand, Markus, et al.
(författare)
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Thin-film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity
- 2023
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Ingår i: Science Advances. - : AMER ASSOC ADVANCEMENT SCIENCE. - 2375-2548. ; 9:25
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Tidskriftsartikel (refereegranskat)abstract
- A design concept of phase-separated amorphous nanocomposite thin films is presented that realizes interfacial resistive switching (RS) in hafnium oxide-based devices. The films are formed by incorporating an average of 7% Ba into hafnium oxide during pulsed laser deposition at temperatures <= 400 degrees C. The added Ba prevents the films from crystallizing and leads to similar to 20-nm-thin films consisting of an amorphous HfOx host matrix interspersed with similar to 2-nm-wide, similar to 5-to-10-nm-pitch Ba-rich amorphous nanocolumns penetrating approximately two-thirds through the films. This restricts the RS to an interfacial Schottky-like energy barrier whose magnitude is tuned by ionic migration under an applied electric field. Resulting devices achieve stable cycle-to-cycle, device-to-device, and sample-to-sample reproducibility with a measured switching endurance of >= 10(4) cycles for a memory window >= 10 at switching voltages of +/- 2 V. Each device can be set to multiple intermediate resistance states, which enables synaptic spike-timing-dependent plasticity. The presented concept unlocks additional design variables for RS devices.
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| 8. |
- Luo, Cheng, et al.
(författare)
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Molecular inhibition mechanisms of cell migration and invasion by coix polysaccharides in A549 NSCLC cells via targeting S100A4
- 2017
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Ingår i: Molecular Medicine Reports. - : Spandidos Publications. - 1791-2997 .- 1791-3004. ; 15:1, s. 309-316
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Tidskriftsartikel (refereegranskat)abstract
- S100 calcium binding protein A4 (S100A4) promotes extracellular signal transduction, intercellular adhesion, motility and mobility. Different extracts from Coix lachryma-jobi have been used for the treatment of various types of cancer in Asia. In our previous study, the polysaccharide fraction extact, CP1, induced cell apoptosis of non-small cell lung cancer cells. In the current study, CP1 inhibited migration and invasion of A549 cells in a scratch wound healing assay and matrigel invasion assay, respectively. Furthermore, reverse transcription-polymerase chain reaction and western blotting demonstrated that CP1 downregulated the gene and protein expression levels of SI00A4. In silico docking analysis demonstrated that polysaccharides may not interfere with dimerization, whereas, the affinity of polysaccharides for an S100A4-NMIIA pocket was margnially greater than at the dimerization sites. Thus, CP1 inhibited A549 cell migration and invasion potentially via downregulation of S100A4, and may also interact with the binding site of S100A4-NMIIA, which indicated that CP1 has potential as an alternative cancer chemotherapeutic by targeting S100A4.
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| 9. |
- Meng, Qinglai, et al.
(författare)
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Rapid Detection of Multiple Classes of β-Lactam Antibiotics in Blood Using an NDM-1 Biosensing Assay
- 2021
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Ingår i: Antibiotics. - : MDPI AG. - 2079-6382. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- Currently, assays for rapid therapeutic drug monitoring (TDM) of β-lactam antibiotics in blood, which might be of benefit in optimizing doses for treatment of critically ill patients, remain challenging. Previously, we developed an assay for determining the penicillin-class antibiotics in blood using a thermometric penicillinase biosensor. The assay eliminates sample pretreatment, which makes it possible to perform semicontinuous penicillin determinations in blood. However, penicillinase has a narrow substrate specificity, which makes it unsuitable for detecting other classes of β-lactam antibiotics, such as cephalosporins and carbapenems. In order to assay these classes of clinically useful antibiotics, a novel biosensor was developed using New Delhi metallo-β-lactamase-1 (NDM-1) as the biological recognition layer. NDM-1 has a broad specificity range and is capable of hydrolyzing all classes of β-lactam antibiotics in high efficacy with the exception of monobactams. In this study, we demonstrated that the NDM-1 biosensor was able to quantify multiple classes of β-lactam antibiotics in blood plasma at concentrations ranging from 6.25 mg/L or 12.5 mg/L to 200 mg/L, which covered the therapeutic concentration windows of the tested antibiotics used to treat critically ill patients. The detection of ceftazidime and meropenem was not affected by the presence of the β-lactamase inhibitors avibactam and vaborbactam, respectively. Furthermore, both free and protein-bound β-lactams present in the antibiotic-spiked plasma samples were detected by the NDM-1 biosensor. These results indicated that the NDM-1 biosensor is a promising technique for rapid TDM of total β-lactam antibiotics present in the blood of critically ill patients.
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| 10. |
- Wang, Aiping, et al.
(författare)
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Loss of NHE8 expression impairs intestinal mucosal integrity
- 2015
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Ingår i: American Journal of Physiology - Gastrointestinal and Liver Physiology. - : American Physiological Society. - 0193-1857 .- 1522-1547. ; 309:11
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Tidskriftsartikel (refereegranskat)abstract
- The newest member of the Na(+)/H(+) exchanger (NHE) family, NHE8, is abundantly expressed at the apical membrane of the intestinal epithelia. We previously reported that mucin 2 expression was significantly decreased in the colon in NHE8(-/-) mice, suggesting that NHE8 is involved in intestinal mucosal protection. In this study, we further evaluated the role of NHE8 in intestinal epithelial protection after dextran sodium sulfate (DSS) challenge. Compared with wild-type mice, NHE8(-/-) mice have increased bacterial adhesion and inflammation, especially in the distal colon. NHE8(-/-) mice are also susceptible to DSS treatment. Real-time PCR detected a remarkable increase in the expression of IL-1β, IL-6, TNF-α, and IL-4 in DSS-treated NHE8(-/-) mice compared with DSS-treated wild-type littermates. Immunohistochemistry showed a disorganized epithelial layer in the colon of NHE8(-/-) mice. Periodic acid-Schiff staining showed a reduction in the number of mature goblet cells and the area of the goblet cell theca in NHE8(-/-) mice. Phyloxine/tartrazine staining revealed a decrease in functional Paneth cell population in the NHE8(-/-) small intestinal crypt. The expression of enteric defensins was also decreased in NHE8(-/-) mice. The reduced mucin production in goblet cells and antimicrobial peptides production in Paneth cells lead to disruption of the intestinal mucosa protection. Therefore, NHE8 may be involved in the establishment of intestinal mucosal integrity by regulating the functions of goblet and Paneth cells.
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