A new class of carboxylate and sulfonate esters of 1‐hydroxy‐2(1H)‐quinolone has been demonstrated as nonionic photoacid generators (PAGs). Irradiation of carboxylates and sulfonates of 1‐hydroxy‐2(1H)‐quinolone by UV light (λ≥310 nm) resulted in homolysis of weak N? O bond leading to efficient generation of carboxylic and sulfonic acids, respectively. The mechanism for the homolytic N? O bond cleavage was supported by time‐dependent DFT calculations. Photoresponsive 1‐(p‐styrenesulfonyloxy)‐2‐quinolone–methyl methacrylate (SSQL‐MMA) and 1‐(p‐styrenesulfonyloxy)‐2‐quinolone–lauryl acrylate (SSQL‐LA) copolymers were synthesized from PAG monomer 1‐(p‐styrenesulfonyloxy)‐2‐quinolone, and subsequently controlled surface wettability was demonstrated for the above‐mentioned photoresponsive polymers. 相似文献
Caged in : The formation of a complex between a peptide ligand and a major histocompatibility complex (MHC) class II protein is detected by a 129Xe biosensor. Cryptophane molecules that trap Xe atoms are modified with a hemagglutinin (HA) peptide, which binds to the MHC protein. The interaction can be monitored by an NMR chemical shift change of cage–HA bound 129Xe.
A happy ending : The germanium(II) hydride [LGeH], where L=[HC{(CMe)(2,6‐iPr2C6H3N)}2], reacts with a diazoalkane to form the hydrazone derivative (see picture). The reaction proceeds through the unprecedented end‐on nitrogen insertion of the diazo compound.
In this study, we realized the continual and long-term electrochemical detection of NO production by stimulated macrophages
using modified porphyrinic microsensor. The NO release from RAW 264.7 cells stimulated by lipopolysaccharide started 5 h after
the lipopolysaccharide administration. After reaching its maximum at the sixth hour, the stable level of NO production was
observed between the seventh and 12th hour of the experiment. This phase was followed by a gradual decline in NO production.
A close correlation between the NO signal detected with microelectrode and nitrite accumulation, which had been determined
in supernatants removed from stimulated cells, was observed. This finding was utilized for the calibration of the electrochemical
experiment. The presence of iNOS enzyme, which constitutes a main requirement for NO production by stimulated macrophages,
was confirmed by Western blot analysis of iNOS protein expression at key time points of the corresponding electrochemical
experiment. The capability of our microsensor to instantaneously monitor the changes in the NO production by stimulated RAW
264.7 cells was demonstrated by the immediate decrease in the signal due to NO as a response to the addition of iNOS inhibitor
into the cell culture medium.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
The first example of nucleophilic substitution with perfluoroalkyl Grignard reagents on the sp3 carbon centre is described. Thus, a series of organometals RF-MgBr, prepared from perfluorinated alkyl iodides RF-I with RF = C4F9, C6F13, C8F17, C10F21 and C12F25, reacted with 1,3,2-dioxathiolane-2,2-dioxide to afford the corresponding 2-(perfluoroalkyl)ethyl magnesium sulfates, which were isolated after metathesis to the corresponding potassium salts. In the model reaction, perfluorohexylmagnesium iodide was reacted with methyl triflate yielding polyfluorinated alkane. The attempts to extend the reaction to 1,3,2-dioxathiane-2,2-dioxide were unsuccessful due to its inferior reactivity and only reduced polyfluoroalkane and the product of coupling were detected in the reaction mixture. Polyfluorinated sulfates are easily hydrolyzed with hydrochloric or triflic acid to the corresponding alcohols, which is an alternative to standard transformation of perfluoroalkyl iodides to 2-(perfluoroalkyl)ethanols. Quantum-chemical calculations of the PES of the reaction with both sulfur-containing heterocycles found that the failure of the reaction with 1,3,2-dioxathiane-2,2-dioxide is caused by higher activation energy of the process. 相似文献
A fingerprinting method for chemical screening of microbial metabolites, potential antibiotics, in spent cultivation broths is described. The method is based on high-throughput ultra-high-performance liquid chromatography (UHPLC) separation with UV detection (photodiode array detector). Thirteen antibiotic standards and four cultivation broths were used for the method development. The comparison of ten liquid–liquid and solid phase extraction protocols for sample clean-up and pre-concentration revealed that Oasis HLB C18 sorbent gives the best recoveries. The Acquity BEH C18 chromatographic column was chosen for the samples separation with respect to its universality, selectivity, efficiency and robustness. The method is presented by two 3D fingerprints for every sample that was obtained under different, acidic and alkaline, UHPLC conditions. The acidic mobile phase consisted of 0.5% phosphoric acid with methanol and the alkaline mobile phase of 1 mM ammonium formate, pH 9 with acetonitrile. Each pair of 3D fingerprints includes the following physico-chemical information: polarity (retention time), presence and characterization of chromophores (UV spectra), compound concentration (detector response), and acid–base properties (influence of different pH of the aqueous parts of mobile phases on retention times). The sample extraction and method validation were assessed with relative standard deviation (RSD) of 0.5, 5.0 and 20.0% for retention times, peak areas and minor compound peak areas, respectively. 相似文献
The aim of this study was to determine whether [131I]apigenin is a powerful and discrimination infection from inflammation for scintigraphic imaging. The study was carried out
in inflamed rats with Staphylococcus aureus (S. aureus) and sterile inflamed rats with turpentine oil. Biodistribution study of [131I]apigenin was performed in the rats. Apigenin was labeled with 131I by iodogen method. Obtained [131I]apigenin with high yield (98%) was injected i.v. to both group rats. The results were expressed as the percent uptake of
injected dose per gram of organ (%ID/g), the bacterial infected and sterile inflamed muscles. Binding of [131I]apigenin to the infected thigh muscle (target muscle = T) and normal thigh muscle (non-target muscle = NT) ratio (T/NT = 4.51
at 15 min) was higher than binding to bacterial inflamed muscle (T/NT = 2.25 at 15 min) of rats. [131I]apigenin showed good localization in both inflamed tissues. This uptake in the sterile inflamed tissue is higher than bacterial
infected tissue. [131I]apigenin might be useful for imaging of inflamed tissues. However, it is not discriminate sterile inflamed tissue from bacterial
infected tissue. 相似文献
The introduction of fluorinated aryls at zinc in Zn(4)N(8)-type (and to a lesser extent Zn(4)N(6)O) cages led to enhanced H(2) uptake. Lithium alkoxides have been shown to link such cages (non-fluorinated), but showed no substantial improvement in uptake. 相似文献
In first‐principles molecular dynamics simulations of the mechanically induced ring‐opening of substituted benzocyclobutene we observe both con‐ and disrotatory ring‐opening reactions. We show that this finding does not contradict the fundamental principle that the orbitals develop continuously in time. However, it constitutes an exception from the principle of the conservation of orbital symmetry and thus is indeed an exception from the Woodward–Hoffmann rules. In contrast, the ring‐opening of unsubstituted cyclobutene proceeds in a conrotatory fashion. This shows that the breaking of the Woodward–Hoffmann rules is significantly facilitated by the substituents.相似文献
The steady rate of development and diffusion of genetically modified plants and their increasing diversification of characteristics,
genes and genetic control elements poses a challenge in analysis of genetically modified organisms (GMOs). It is expected
that in the near future the picture will be even more complex. Traditional approaches, mostly based on the sequential detection
of one target at a time, or on a limited multiplexing, allowing only a few targets to be analysed at once, no longer meet
the testing requirements. Along with new analytical technologies, new approaches for the detection of GMOs authorized for
commercial purposes in various countries have been developed that rely on (1) a smart and accurate strategy for target selection,
(2) the use of high-throughput systems or platforms for the detection of multiple targets and (3) algorithms that allow the
conversion of analytical results into an indication of the presence of individual GMOs potentially present in an unknown sample.
This paper reviews the latest progress made in GMO analysis, taking examples from the most recently developed strategies and
tools, and addresses some of the critical aspects related to these approaches. 相似文献