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排序方式: 共有207条查询结果,搜索用时 15 毫秒
111.
Darko Anđelković Milica Branković Gordana Kocić Sanja Mitić Radmila Pavlović 《Biomedical chromatography : BMC》2020,34(1):e4720
Apple peel is frequently exposed to pesticides, especially in the last stages of the pesticide treatment practice. For a certain period, peel retains most of the applied pesticides, which precisely indicates the presence of pesticide residues. This study was conducted to establish and evaluate the method for the residue analysis of pyrimethanil, cyprodinil, trifloxystrobin, bifenthrin and boscalid by GC–MS in peel of Granny Smith, Golden Delicious and Idared varieties. The method consisted of few steps, without the routine usage of sorbents, and resulted in efficient removal of waxes, targeted as main interferences in GC–MS analysis. The matrix effect, boscalid selectivity issue, trend of lower trueness for bifenthrin in all matrices and for all analytes in Granny Smith matrix were in some way associated with the waxes. Finally, the method was applied to the analysis of three varieties of apple orchard samples, after 9 and 5 months of treatment with commercial formulations that contain pyrimethanil, cyprodinil and boscalid as active ingredients. Since the developed method consisted of few steps and used nontoxic and economic reagents, it could be implemented as a fast, economic and reliable screening method. 相似文献
112.
Maria-Gabriela Alexandru Tanja Cirkovic Velickovic Ioana Jitaru Sanja Grguric-Sipka Constantin Draghici 《Central European Journal of Chemistry》2010,8(3):639-645
This paper presents the synthesis of complex compounds of type [M(L1)2], where M(II)= Cu (1), Co (2), Zn (3), L1=2-aminothiazole-4-acetate and [Mn(L1)2(H2O)] (4) using ethyl 2-(2-aminothiazole-4-yl) acetate (L), and characterization by elemental analysis, magnetic susceptibilities,
IR, 1H-NMR, UV-Vis spectroscopy and for [Mn(L1)2(H2O)] also by X-ray diffraction. In vitro cytotoxicity studies were performed on human cervix adenocarcinoma, HeLa cells. The
antitumor selectivity was assessed using normal human peripheral blood mononuclear cells, PBMC as control.
相似文献
113.
Hyper-heuristics or “methodologies to choose heuristics” are becoming increasingly popular given their suitability to solve
hard real world combinatorial optimisation problems. Their distinguishing feature is that they operate in the space of heuristics
or heuristic components rather than in the solution space. In Dispatching Rule Based Genetic Algorithms (DRGA) solutions are
represented as sequences of dispatching rules which are called one at a time and used to sequence a number of operations onto
machines. The number of operations that each dispatching rule in the sequence handles is a parameter to which DRGA is notoriously
sensitive. This paper proposes a new hybrid DRGA which searches simultaneously for the best sequence of dispatching rules
and the number of operations to be handled by each dispatching rule. The investigated DRGA uses the selection mechanism of
NSGA-II when handling multi-objective problems. 相似文献
114.
Background
Autoantibodies directed against the 160 kDa endosome protein early endosome antigen 1 (EEA1) are seen in patients with neurological diseases. To determine if antibodies to EEA1 have a neuropathological effect, mice from three major histocompatability haplotype backgrounds (H2q, H2b and H2d) were immunized with EEA1 (amino acids 82–1411) that was previously shown to contain the target EEA1 epitopes. The mice were then subjected to five neuro-behavioural tests: grid walking, forelimb strength, open field, reaching and rotarod. 相似文献115.
Milan B. Jovanovic Zoran Mulutinovic Jelena Perovic Andrej Grubor Sanja Milenkovic Slobodan Malobabic 《Journal of voice》2007,21(3):355-360
AIM: To evaluate contact telescopy findings for estimation of blood vessel changes in vocal fold mucosa in patients with Reinke's edema. Histological features significant for diagnosis of microvascular vocal fold alteration were correlated with clinical findings. METHODS: In 80 patients with Reinke's edema, laryngoscopy and video-telescopy image analysis of vocal folds were performed. Vocal fold mucosa biopsies were histologically analyzed and compared with contact telescopy findings. An interesting aspect of vocal fold microcirculation found both by contact telescopy imiging and by histological specimens was described. RESULTS: Contact telescopy in vivo revealed different forms of pathological blood vessel networks with unusual appearance of loops or branching. Some dilated varicose vascular channels had very thin walls, and within atypical capillaries, partial erythrocyte accumulation was found. Details of blood flow are also visible, showing multidirectional and discontinuous blood flow in neighboring vessels. CONCLUSION: The noninvasive contact telescope technique is very useful as an additional diagnostic tool for defining a condition of a subepithelial Reinke's space in a very short period of time. The great advantage of contact telescopy is systematic in vivo and in situ observation of microvascular details in the vocal folds. The contact technique allows dynamic follow-up of the microcirculation in Reinke's edema as well as simultaneous consultation of a pathologist in the operating theater. 相似文献
116.
Sanja Varošanec 《Journal of Mathematical Analysis and Applications》2007,326(1):303-311
We introduce a class of h-convex functions which generalize convex, s-convex, Godunova-Levin functions and P-functions. Namely, the h-convex function is defined as a non-negative function which satisfies f(αx+(1−α)y)?h(α)f(x)+h(1−α)f(y), where h is a non-negative function, α∈(0,1) and x,y∈J. Some properties of h-convex functions are discussed. Also, the Schur-type inequality is given. 相似文献
117.
Binding behavior of amino acid conjugates of indole-3-acetic acid to immobilized human serum albumin
The affinity of indole-3-acetic acid (IAA), indole-3-propionic acid, indole-3-butyric acid and 24 of their amino acid conjugates to immobilized human serum albumin, as expressed by the retention factor k (determined by HPLC), was dependent on (1) lipophilicity, (2) chirality and (3) functional groups in the amino acid moiety; in some cases conformation plays an additional role. Two lipophilicity-related parameters afforded quantitative correlations with k: retention on a C18 reversed-phase column (experimental approach) and the distance between the hydrophilic and hydrophobic poles of the molecules (in silico approach). Most compounds examined are possible metabolic precursors of IAA, an experimental tumor therapeutic. 相似文献
118.
An operationally much simpler method for the extraction of thermochemical data from energy-resolved collision-induced dissociation cross sections, which is specifically designed for ligand binding energy determinations by tandem mass spectrometry, is presented. Compared to previous methods available in the literature, the present method has three advantages: (i) A more realistic treatment of the electrostatic potential for the approach of the ion to the collision partner leads to a better, nonempirical threshold function, allowing fitting of the cross section over the entire energy range rather than just the onset. (ii) Treatment of the kinetic shift with a new model for the density-of-states function eliminates the need for explicit entry of frequencies for the starting ion or the transition state without loss of accuracy relative to direct state counts. (iii) Data fitting using Monte Carlo simulation and a genetic algorithm instead of the usual Marquardt-Levenburg least-squares routines not only produces an equivalent fit but also produces statistically relevant error bounds on the derived fit parameters. Although the method is conceived for medium-to-large organometallic complexes, the theory is general enough to be appropriate for a wide range of binding phenomena of a small molecule to a larger one observed in mass spectrometry. 相似文献
119.
120.
Dictyotaceae, the large family of brown algae with the genus Dictyota as the richest one among them, produce a significant number of secondary metabolites, like diterpenes. The aim of this study was to investigate the variations in the composition of the volatile organic compounds (VOCs) of the brown alga Dictyota dichotoma collected from the Adriatic Sea. For the first time, both seasonal changes and the impact of air drying were examined. Headspace solid-phase microextraction (HS-SPME) on two fibres with different polarities and hydrodistillation (HD), followed by gas chromatography and mass spectrometry (GC-MS) analysis, was performed on both fresh (FrDd) and air-dried (DrDd) D. dichotoma. The major compounds of HS-FrDd were pentadecane and oct-1-en-3-ol. The percentage of pentadecane in HS-DrDd was increased up to 7.8 times in comparison with HS-FrDd. Principal component analysis (PCA) identified differences between the variability of data among fresh and dried samples over months and clearly dissociated the fresh May samples from the others in the HS-SPME results. The most abundant group of VOCs in HD were terpenes, with diterpenes isopachydictyol A and cembra-4,7,11,15-tetraen-3-ol as the major compounds. Diterpene pachydictyol A was also found and among sesquiterpenes and gleenol was the most abundant. Based on the dominant compound analyses, the PCA showed distinct separation of the fresh and dried samples, indicating similarities between the samples and allowing the establishment of typical VOCs significant for the chemotaxonomy of D. dichotoma. 相似文献