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排序方式: 共有90条查询结果,搜索用时 15 毫秒
21.
S. Del Gaudio A. Cirillo G. Di Bernardo U. Galderisi M. Cipollaro 《Analytical and bioanalytical chemistry》2010,396(6):2135-2142
DNA is widely used as a target for GMO analysis because of its stability and high detectability. Real-time PCR is the method
routinely used in most analytical laboratories due to its quantitative performance and great sensitivity. Accurate DNA detection
and quantification is dependent on the specificity and sensitivity of the amplification protocol as well as on the quality
and quantity of the DNA used in the PCR reaction. In order to enhance the sensitivity of real-time PCR and consequently expand
the number of analyzable target genes, we applied a preamplification technique to processed foods where DNA can be present
in low amounts and/or in degraded forms thereby affecting the reliability of qualitative and quantitative results. The preamplification
procedure utilizes a pool of primers targeting genes of interest and is followed by real-time PCR reactions specific for each
gene. An improvement of Ct values was found comparing preamplified vs. non-preamplified DNA. The strategy reported in the
present study will be also applicable to other fields requiring quantitative DNA testing by real-time PCR. 相似文献
22.
C.?Cirillo S.?L.?Prischepa M.?Salvato C.?AttanasioEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,38(1):59-64
We have investigated, in the framework of proximity effect theory, the interface transparency
of superconducting/normal metal layered systems which consist of Nb and high paramagnetic Pd deposited by dc magnetron sputtering. The obtained
value is relatively high, as expected by theoretical arguments. This leads to a large value of the ratio
although Pd does not exhibit any magnetic ordering.Received: 12 December 2003, Published online: 20 April 2004PACS:
74.45. + c Proximity effects; Andreev effect; SN and SNS junctions - 74.78.Fk Multilayers, superlattices, heterostructuresS.L. Prischepa: Permanent address: State University of Computer Science and RadioElectronics, P. Brovka street 6, 220600, Minsk, Belarus 相似文献
23.
I never satisfy myself until I can make a mechanical model of a thing. If I can make a mechanical model I can understand it. As long as I cannot make a mechanical model all the way through I cannot understand...... 相似文献
24.
M. Salvato F. Bobba G. Calabrese C. Cirillo A. M. Cucolo A. De Santis A. Vecchione C. Attanasio 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(1):79-85
Resistivity vs. temperature measurements on
La0.7Ca0.3MnO3/YBa2Cu3O7-δ
/La0.7Ca0.3MnO3 (LCMO/YBCO/LCMO) trilayers with different
YBCO thickness, were performed in external magnetic field H up to 8 T. By
evaluating the activation energy U from the slope of the resistivity
Arrhenius plot, a strong depression of U has been observed when decreasing
the YBCO layer thickness and the absolute U values appear to be reduced with
respect to the values reported in literature in the case of YBCO thin films
and YBCO/insulating multilayers. Moreover, a logarithmic U vs. H dependence is
shown both in the case of thick and thin YBCO layers indicating the
formation of a two dimensional vortex lattice. The experimental data are
discussed considering the strong influence of the ferromagnetic LCMO on the
superconducting YBCO properties which reduces the effective YBCO thickness
more than predicted by the conventional theories. 相似文献
25.
Removal of metal ions from aqueous solution by chelating polymeric microspheres bearing phytic acid derivatives 总被引:1,自引:0,他引:1
Francesca Iemma Giuseppe Cirillo Umile Gianfranco Spizzirri Francesco Puoci Ortensia Ilaria Parisi Nevio Picci 《European Polymer Journal》2008,44(4):1183-1190
The aim of this study was to investigate the possibility to synthesize new chelating polymeric microspheres owing immobilized biocompatible agent as chelating functional groups and to evaluate their performance in metal ions removal from aqueous solution.The microparticles were synthesized via precipitation polymerization of 4-O-(4-vinylbenzyl)-myo-inositol 1,3,5-orthoformate with ethylene glycol dimethacrylate (EGDMA) and subsequent exhaustive phosphorylation of myo-inositol groups using phosphoric acid.Spherical geometry with monodisperse nature of the polymeric microparticles was confirmed by scanning electron micrographs (SEM) and dimensional analysis. A large surface area of the microspheres provided a maximum interaction of metal ions and the chelating functional groups on the surface. Absorption capacity of the beads for the selected metal ions, i.e., Cu(II), Ni(II), Fe(III), was investigated in detail in aqueous solution at pH 5.0 utilizing UV/Vis spectroscopy. This study showed that the macromolecular systems are very effective in chelating these metal ions and the affinity order of the microbeads toward metal ions is: Fe(III) > Ni(II) > Cu(II).The chelating beads can be easily regenerated by 1.0 M HNO3 with high effectiveness. These features make the synthesized beads a potential candidate for metal ions removal at high capacity. 相似文献
26.
A new sorbent for molecularly imprinted solid phase extraction (MISPE) was synthesized to extract and purify α-tocopherol (α-TP) from vegetable sources. Molecularly imprinted polymers (MIP) were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent using a photo-polymerization procedure. A thermo-polymerization was also performed but no imprinting effect in the resulting materials was raised.The proposed MISPE protocol could overcome the drawback of traditional detection methods, which require pre-treatments of the samples. The possibility to obtain the selective recognition of α-TP from natural samples in aqueous mixtures represents one of the main advantages of our materials. Our procedure involves the direct HPLC injection of eluate without any treatment and above all the use of no toxic and biocompatible organic solvents.After the evaluation of the selectivity of the α-TP imprinted polymers, the performance of these materials as solid phase extraction (SPE) sorbents was investigated. Our MISPE-HPLC procedure has a high sensitivity, LOD and LOQ were 3.49 × 10−7 and 1.16 × 10−6 mol L−1, respectively, as well as good precision (intraday precision below 3.3% and interday precisions below 6.5%) and recovery (60%). Thus, it can be successfully used for the purification of α-TP from bay leaves. 相似文献
27.
A new method for the determination of biogenic amines in cheese by LC with evaporative light scattering detector 总被引:1,自引:0,他引:1
Restuccia D Spizzirri UG Puoci F Cirillo G Curcio M Parisi OI Iemma F Picci N 《Talanta》2011,85(1):363-369
This paper presents a new LC method with evaporative light scattering detection (ELSD), for the separation and determination of the biogenic amines (histamine, spermidine, spermine, tyramine, putrescine and β-phenylethylamine) which are commonly present in cheese, as their presence and relative amounts give useful information about freshness, level of maturing, quality of storage and cheese authentication. The LC-ELSD method is validated by comparison of the results with those obtained through LC-UV determination, based on a pre-column dansyl chloride derivatisation step. The obtained data demonstrate that both methods can be interchangeably used for biogenic amines determination in cheese. The new LC-ELSD method shows good precision and permits to achieve, for standard solutions, limit of detection (LOD) values ranging from 1.4 to 3.6 mg L−1 and limit of quantitation (LOQ) values ranging from 3.6 to 9.3 mg L−1. The whole methodology, comprehensive of the homogenization-extraction process and LC-ELSD analysis, has been applied in the analysis of a typical Calabria (Southern Italy) POD cheese, known as Caciocavallo Silano. The most aboundant amine found was histamine, followed, in decreasing order, by tyramine, spermine, putrescine, β-phenylethylamine and spermidine, for a total amount of 127 mg kg−1. This value does not represent a possible risk for consumer health, according to the toxicity levels reported in literature and regarded as acceptable. 相似文献
28.
L Ricciardi F Puoci G Cirillo M La Deda 《Dalton transactions (Cambridge, England : 2003)》2012,41(36):10923-10925
The grafting of a 2-picolylamine Pt(ii) complex into polymethacrylic acid has been successfully performed. The obtained polymer is water soluble, and it represents the first example of a platinum-containing polymer able to photogenerate singlet oxygen. 相似文献
29.
F. Iemma U. G. Spizzirri F. Puoci G. Cirillo M. Curcio O. I. Parisi N. Picci 《Colloid and polymer science》2009,287(7):779-787
Novel thermo-responsive hydrophilic microspheres were prepared by free radical polymerization of methacrylate bovine serum
albumin and N-isopropylacrylamide, as cross-linker and functional monomer, respectively. The incorporation of monomers in the network was
confirmed by infrared spectroscopy, while the network density and shape of hydrogels strictly depend on concentration of monomers
in the polymerization feed. The thermal analyses showed negative thermo-responsive behavior with pronounced water affinity
of microspheres at temperature lower than lower critical solution temperature (LCST). The in vitro release studies of drug-loaded
thermo-sensitive hydrogels were performed. Experimental data showed, for the copolymers with functional monomer/cross-linker
ratio ≤ 1, a predominant drug release in the collapsed state, while the copolymers with functional monomer/cross-linker ratio > 1
showed prominent drug release in the swollen state. Below the hydrogel LCST, drug release through the swollen polymeric networks
was observed, while a squeezing-out effect at temperature above the LCST was predominant. 相似文献
30.
The catalytic activity of snowman-like and core-shell Fe3O4/Au nanoparticles (NPs), obtained through a “wet chemistry” approach which directly restitutes nanocatalysts stable and highly active in the reaction medium, was tested towards N-alkylation reactions. The nanocatalysts were tested for the synthesis of secondary amines. The core-shell NPs, thanks to the surface properties, homogeneous dispersion and intimate connection with reagents in the catalyst medium, exhibited an excellent catalytic activity (e. g. >99 % yield and conversion of aniline in very short time and mild conditions). Owing to the magnetic part, the nanoparticles can be easily separated and reused, showing an almost stable activity after 10 cycles. 相似文献