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31.
Dentuto PL Catucci L Cosma P Fini P Agostiano A D'Accolti L Trevithick-Sutton CC Foote CS 《The journal of physical chemistry. B》2005,109(3):1313-1317
The interactions between chlorophyll a and two beta-cyclodextrins, that have the same cavity size but different substituents, were studied in aqueous solutions. These supramolecular host-guest complexes were examined by a combination of UV/vis absorption, circular dichroism, NMR, and steady-state and time-resolved fluorescence measurements. The results indicate that all cyclodextrins solubilize the pigment mainly in monomeric form in water. The pigment forms 1:1 complexes with the heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin and 1:2 complexes with the hydroxypropyl-beta-cyclodextrin. In such complexes the methyl groups of the cyclodextrin inner cavity are involved in the interaction with the pigment as evidenced by NMR measurements. We also measured the luminescence of singlet oxygen photosensitized by chlorophyll a in the inclusion complexes. 相似文献
32.
B. Cosma F. Soggia M. L. Abelmoschi R. Frache 《International journal of environmental analytical chemistry》2013,93(1-4):121-128
Abstract Trace metals (Cu, Pb, Zn, Cd, Cr, Ni, Co, Mn) and iron concentration were determined in several sediments collected in the Antarctica (Terra Nova Bay—Ross Sea). Samples were analyzed by inductively coupled plasma (ICP-AES) after selective and total extraction. The results are in good agreement with the data previously collected in the same area. 相似文献
33.
O. A. Dumitru R. Cs. Begy D. C. Nita L. D. Bobos C. Cosma 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):1335-1339
In this paper a simple method was used to design and set up an electrodeposition device for uranium source preparation for alpha spectrometry measurements. The aim of this work is to find the optimal parameters to be used to achieve uranium alpha sources with good spectral properties and maximum yield of the electrodeposition process. Samples with specific uranium activity were prepared from aqueous solution of uranyl nitrate hexahydrate (UO2 (NO3)2·6H2O). A series of preliminary experiments was conducted to establish the main parameters that have a significant influence on the deposition efficiency. Among these, the electrodeposition time was studied and the optimum time was found to be 1 h, in the case of our home-made deposition cell. It was also shown that a current of 1,500 mA, plating time of 60 min and pH range of 2–2.2 are the best conditions for deposition of uranium. The alpha spectrometry results show a good spectral resolution for the uranium sources obtained by the electrodeposition using the optimal parameters. 相似文献
34.
35.
Rohilla Aman Guangshun LI Jianguo WANG Minliang LIU Xiaohong ZHOU Song GUO Yunhua QIANG Bing DING Dongsheng HOU Shan HUANG 《原子核物理评论》2020,37(3):542-547
在本工作中,我们主要研究了101Pd核中$ \nu_{11/2} $ 带的能级结构,并与临近同位素相对应的能级结构进行了对比。研究发现在Pd同位素链,即$ N\!= \!Z\! =\! 50 $ 的壳附近,三轴形变的演变符合很好的系统性,即从小的不稳定形变逐渐演变为稳定的长椭形变。同时,我们也做了总势能面(TRS)随着原子核转动频率以及中子数变化的系统计算,结果也支持该核区不稳定三轴形变演化的规律。 相似文献
36.
Ventrella Andrea Verrone Raffaella Cosma Pinalysa Fini Paola Longobardi Francesco Lippolis Vincenzo Pascale Michelangelo Catucci Lucia 《Journal of solution chemistry》2014,43(8):1436-1447
Journal of Solution Chemistry - The interaction of ochratoxin A (OTA) with heptakis-2,6-di-O-methyl-β-cyclodextrin (DIMEB) in aqueous solutions at two different pHs (3.5 and 9.5) was studied... 相似文献
37.
Lavinia E. Muntean Constantin Cosma Dorin V. Moldovan 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):523-532
As building materials are known to be the second source regarding high radon concentrations, it is very important to determine the amounts of natural radionuclides from every building material in use. In the present study the most frequently used Romanian natural (sand, gypsum, limestone) and artificial (portland cement, lime, clinker, electrofilter powder, fly ash, cement-lime plaster mortar, cement plaster mortar) building materials were analyzed. The absorbed dose rate and the annual effective dose equivalent rate for people living in dwelling buildings made of these building materials under investigation were also calculated. The analysis was performed with gamma-ray spectrometry, with two hyper-pure germanium detectors. The activity concentrations of natural radionuclides were in the ranges: 5.2–511.8 Bq kg?1 for 226Ra; 0.6–92.6 Bq kg?1 for 232Th and <1–1,720.7 Bq kg?1 for 40K, respectively. The radium equivalent activity in the fifty-one (51) samples varied from 9 to 603 Bq kg?1. By calculating all the radioactivity indices (Raeq, H ext, I α, I yr) it was found that all the building materials under investigation can be used to erect dwelling buildings. Except for sample SA6, SA7 and SA11 among the natural building materials and sample SG1, SG2, FAH1, CLM1, CM1 among the artificial building materials that are considered hazardous materials when are used in large quantities. 相似文献
38.
O. A. Rusu S. Dreve R. Cs. Begy D. C. Nita L. D. Bobos C. Cosma 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):241-245
Alpha spectrometry is an extremely useful and sensitive for detection of alpha-emitting nuclides. Contamination of the silicon
detectors for low-level alpha spectrometry by recoil nuclides is a serious problem in the measurement of alpha emitters decaying
to daughter nuclides with short half-lives. This unwanted contamination leads to decreased measurement sensitivity causing
a degradation of the limit of detection. The simplest method to prevent this radioactive contamination of detector is to use
a catcher film between the alpha source and the detector. In this work we describe the obtaining of the thin formvar films
as stopper foils for recoil nuclei and we investigated the influence of these films on alpha spectrometry parameters, as energy
shift (~30 keV) and resolution (~7%). No significant deterioration of the alpha spectrometry parameters was observed when
using thin formvar films. Using the ASTAR web databases, which calculate stopping powers for alpha particles, the thickness
of formvar films was estimated to be about 5.355 × 10−5 g/cm2. The measurements were performed with an ORTEC SOLOIST alpha spectrometer with PIPS detector. 相似文献
39.
40.
Chiara Mongioví Dario Lacalamita Nadia Morin-Crini Xavier Gabrion Aleksandra Ivanovska Federico Sala Vincent Placet Vito Rizzi Jennifer Gubitosa Ernesto Mesto Ana Rita Lado Ribeiro Paola Fini Nicoletta De Vietro Emanuela Schingaro Mirjana Kosti Cesare Cosentino Pinalysa Cosma Corina Bradu Gilles Chanet Grgorio Crini 《Molecules (Basel, Switzerland)》2021,26(15)
FINEAU (2021–2024) is a trans-disciplinary research project involving French, Serbian, Italian, Portuguese and Romanian colleagues, a French agricultural cooperative and two surface-treatment industries, intending to propose chènevotte, a co-product of the hemp industry, as an adsorbent for the removal of pollutants from polycontaminated wastewater. The first objective of FINEAU was to prepare and characterize chènevotte-based materials. In this study, the impact of water washing and treatments (KOH, Na2CO3 and H3PO4) on the composition and structure of chènevotte (also called hemp shives) was evaluated using chemical analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray computed nanotomography (nano-CT), attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, solid state NMR spectroscopy and thermogravimetric analysis. The results showed that all these techniques are complementary and useful to characterize the structure and morphology of the samples. Before any chemical treatment, the presence of impurities with a compact unfibrillated structure on the surfaces of chènevotte samples was found. Data indicated an increase in the crystallinity index and significant changes in the chemical composition of each sample after treatment as well as in surface morphology and roughness. The most significant changes were observed in alkaline-treated samples, especially those treated with KOH. 相似文献