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排序方式: 共有699条查询结果,搜索用时 46 毫秒
121.
122.
Dr. Mauro Carraro Dr. Giulia Fiorani Dr. Lorenzo Mognon Dr. Francesca Caneva Dr. Martino Gardan Dr. Chiara Maccato Dr. Marcella Bonchio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13195-13202
Anchoring terminal octenyl tails on molecular polyoxotungstates yield polymerizable organic–inorganic monomers with formula [{CH2?CH(CH2)6Si}xOySiWwOz]4? [x=2, w=11, y=1, z=39 ( 1 ); x=2, w=10, y=1, z=36 ( 2 ); and x=4, w=9, y=3, z=34 ( 3 )]. These molecular hybrids can use aqueous hydrogen peroxide to catalyze the selective oxidation of organic sulfides in CH3CN. Copolymerization of 1 – 3 with methyl methacrylate and ethylene glycol dimethacrylate leads to porous materials with a homogeneous distribution of the functional monomers, as indicated by converging evidence from FTIR spectroscopy and electronic microscopy. The catalytic polymers activate hydrogen peroxide for oxygen transfer, as demonstrated by the quantitative and selective oxidation of methyl p‐tolyl sulfide, which was screened as model substrate. The hybrid material containing monomer 2 was also tested in n‐octane to evaluate its potential for the oxidation and removal of dibenzothiophene, a well‐known gasoline contaminant. 相似文献
123.
Alessandro Massella Giulia D'Intino Mercedes Fernández Sandra Sivilia Luca Lorenzini Silvia Giatti Roberto C Melcangi Laura Calzà Luciana Giardino 《BMC neuroscience》2012,13(1):12
Background
Multiple sclerosis (MS) varies considerably in its incidence and progression in females and males. In spite of clinical evidence, relatively few studies have explored molecular mechanisms possibly involved in gender-related differences. The present study describes possible cellular- and molecular-involved markers which are differentially regulated in male and female rats and result in gender-dependent EAE evolution and progression. Attention was focused on markers of myelination (MBP and PDGFαR) and neuronal distress and/or damage (GABA synthesis enzymes, GAD65 and GAD67, NGF, BDNF and related receptors), in two CNS areas, i.e. spinal cord and cerebellum, which are respectively severely and mildly affected by inflammation and demyelination. Tissues were sampled during acute, relapse/remission and chronic phases and results were analysed by two-way ANOVA. 相似文献124.
Three related cyclic peptides, aeruginazole DA1497 (1), aeruginazole DA1304 (2), and aeruginazole DA1274 (3), were isolated from the freshwater cyanobacteria, Microcystis aeruginosa, bloom material collected on October 2007 from the Dalton water-reservoir in Northern Israel. Aeruginazoles DA1304 (2), DA1338 (4), and DA1372 (5) were isolated as an inseparable mixture from a bloom material of M. aeruginosa collected from the same water-reservoir on August 2000. Their structures were elucidated using a combination of various spectroscopic techniques, mainly NMR and MS, while the absolute stereochemistry of the chiral centers were determined by Marfey’s method. Aeruginazoles 1–3 were tested in various bioassays (antibacterial, cytotoxicity, and protease inhibition). Aeruginazole DA1497 (1) showed a mild antimicrobial activity against Staphylococcus aureus, but was inactive like the rest of the compounds in all other bioassays. 相似文献
125.
Optimization of a SPME/GC/MS Method for the Simultaneous Determination of Pharmaceuticals and Personal Care Products in Waters 总被引:2,自引:0,他引:2
A headspace solid phase microextraction (HS-SPME) method coupled with gas chromatography and MS detection (GC/MS) was optimized for the simultaneous determination of 21 target Pharmaceuticals and Personal Care Products (PPCPs) in water samples. The analytes included fragrances, UV-filters, antiseptics, estrogens, anti-inflammatory drugs, and pesticides. An on-fiber SPME derivatization, using silyl reagents, was performed for the analysis of more polar acidic compounds. An experimental design approach was applied to systematically investigate and optimize the operative parameters affecting the extraction recovery, namely: extraction temperature and time, derivatization time, desorption temperature and time. The optimum operating conditions were: extraction time of 125?min at a temperature of 40?°C; derivatization time of 30.5?min; desorption time of 2?min at a temperature of 300?°C. Under these conditions, good reproducibility was assessed as RDS% values ≤10% for underivatized PPCPs and ≤20% for derivatized compounds. The method detection limits (LOD) were between 0.7 and 9.0?ng?L?1, with the highest values in the range 2.5–9.0?ng?L?1 for the derivatized analytes. Method accuracy was evaluated on spiked tap water samples: recoveries varied from 85 to 103% and from 75 to 110% for non-derivatized and derivatized compounds, respectively. 相似文献
126.
127.
Let G be a connected graph with least eigenvalue –2, of multiplicity k. A star complement for –2 in G is an induced subgraph H = G – X such that |X| = k and –2 is not an eigenvalue of H. In the case that G is a generalized line graph, a characterization of such subgraphs is used to decribe the eigenspace of –2. In some instances, G itself can be characterized by a star complement. If G is not a generalized line graph, G is an exceptional graph, and in this case it is shown how a star complement can be used to construct G without recourse to root systems. 相似文献
128.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. 相似文献
129.
Matteo Mori Giulia Cazzaniga Fiorella Meneghetti Stefania Villa Arianna Gelain 《Molecules (Basel, Switzerland)》2022,27(14)
SIRT5 is a member of the Sirtuin family, a class of deacetylating enzymes consisting of seven isoforms, involved in the regulation of several processes, including gene expression, metabolism, stress response, and aging. Considering that the anomalous activity of SIRT5 is linked to many pathological conditions, we present herein an overview of the most interesting modulators, with the aim of contributing to further development in this field. 相似文献
130.
Vincenzo Algieri Paola Costanzo Matteo Antonio Tallarida Fabrizio Olivito Antonio Jiritano Giulia Fiorani Francesca Peccati Gonzalo Jimnez-Oss Loredana Maiuolo Antonio De Nino 《Molecules (Basel, Switzerland)》2022,27(23)
1,2,3-triazoles are versatile building blocks with growing interest in medicinal chemistry. For this reason, organic chemistry focuses on the development of new synthetic pathways to obtain 1,2,3-triazole derivatives, especially with pyridine moieties. In this work, a novel series of 1,5-disubstituted-1,2,3-triazoles functionalized with pyrimidine nucleobases were prepared via 1,3-dipolar cycloaddition reaction in a regioselective manner for the first time. The N1-propargyl nucleobases, used as an alkyne intermediate, were obtained in high yields (87–92%) with a new two-step procedure that selectively led to the monoalkylated compounds. Then, FeCl3 was employed as an efficient Lewis acid catalyst for 1,3-dipolar cycloaddition between different aryl and benzyl azides and the N1-propargyl nucleobases previously synthesized. This new protocol allows the synthesis of a series of new 1,2,3-triazole derivatives with good to excellent yields (82–92%). The ADME (Absorption, Distribution, Metabolism, and Excretion) analysis showed good pharmacokinetic properties and no violations of Lipinsky’s rules, suggesting an appropriate drug likeness for these new compounds. Molecular docking simulations, conducted on different targets, revealed that two of these new hybrids could be potential ligands for viral and bacterial protein receptors such as human norovirus capsid protein, SARS-CoV-2 NSP13 helicase, and metallo-β-lactamase. 相似文献