排序方式: 共有187条查询结果,搜索用时 93 毫秒
41.
Bartosz J. Pachno Maciej Strzemski Sawomir Dresler Lubomír Adamec Kamila Wojas-Krawczyk Ireneusz Sowa Anna Danielewicz Vitor F. O. Miranda 《Molecules (Basel, Switzerland)》2021,26(1)
The genus Aldrovanda is a Palaeogene element containing a single extant species, Aldrovanda vesiculosa L. This aquatic carnivorous herb has a very wide range of distribution, natively covering four continents; however, it is a critically endangered aquatic plant species worldwide. Previous studies revealed that A. vesiculosa had an extremely low genetic variation. The main aim of the present paper is to explore, using chemometric tools, the diversity of 16 A. vesiculosa populations from various sites from four continents (Eurasia, Africa, Australia). Using chemometric data as markers for genetic diversity, we show the relationships of 16 A. vesiculosa populations from various sites, including four continents. Phytochemical markers allowed the identification of five well-supported (bootstrap > 90%) groups among the 16 populations sampled. The principal component analysis data support the idea that the strongly related African (Botswana) and Australian (Kimberley, NT, NW Australia) populations are the most distant ones, separated from the European and Asian ones. However, considering the five Australian populations sampled, three are nested within the Eurasian group. The chemometric data are correlated positively with the geographical distances between the samples, which suggests a tendency toward isolation for the most distant populations. 相似文献
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Anton Pljonkin Dmitry Petrov Lilia Sabantina Kamila Dakhkilgova 《Entropy (Basel, Switzerland)》2021,23(5)
The article is focused on research of an attack on the quantum key distribution system and proposes a countermeasure method. Particularly noteworthy is that this is not a classic attack on a quantum protocol. We describe an attack on the process of calibration. Results of the research show that quantum key distribution systems have vulnerabilities not only in the protocols, but also in other vital system components. The described type of attack does not affect the cryptographic strength of the received keys and does not point to the vulnerability of the quantum key distribution protocol. We also propose a method for autocompensating optical communication system development, which protects synchronization from unauthorized access. The proposed method is based on the use of sync pulses attenuated to a photon level in the process of detecting a time interval with a signal. The paper presents the results of experimental studies that show the discrepancies between the theoretical and real parameters of the system. The obtained data allow the length of the quantum channel to be calculated with high accuracy. 相似文献
43.
To help to clarify therapeutic functions of lipoic acid (LA) in biochemical and clinical practice we have elaborated a fast, simple and accurate HPLC method enabling determination of LA in human urine. The proposed analytical approach includes reduction of LA with tris(2‐carboxyethyl)phosphine and simultaneous separation and derivatization of the analyte with butylamine and o‐phthaldialdehyde followed by spectrofluorimetric detection at λex = 340 nm and λem = 440 nm. The assay was performed using gradient elution and the mobile phase containing 0.0025 mol L?1 o‐phthaldialdehyde in 0.0025 mol L?1 NaOH and acetonitrile. Linearity of the detector response for LA was observed in the range of 0.3–8 μmol L?1. Limits of detection and quantification for LA in urine samples were 0.02 and 0.03 μmol L?1, respectively. The total analysis time, including sample work‐up, was <20 min. The analytical procedure was successfully applied to analysis of real urine samples delivered from six healthy volunteers who received a single 100 mg dose of LA. 相似文献
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Kamila Pruszkowska Olga A. Stasyuk Anna Zep Adam Krówczyński Rafal R. Sicinski Miquel Solà Michał K. Cyrański 《Chemphyschem》2022,23(2):e202100741
Two new square planar ONNO nickel(II) complexes C2_core and C3_core have been synthesized and characterized by single crystal X-ray diffraction, NMR spectroscopy, thermogravimetry, and DFT calculations. The experimental results revealed the effect of the length of diamine bridge in the ligand on the behavior of the studied complexes in the reaction with N-heterocyclic aromatic amines, while DFT calculations provided a basis for the rationalization of this observation. The complex with propylenediamine bridge ( C3_core ) readily reacts with pyridine and its derivatives to form high-spin (paramagnetic) complexes with octahedral geometry as characterized by X-ray diffraction; electron-donating substituents on the pyridine ring facilitate the coordination of axial ligands. In contrast, the complex with ethylenediamine bridge ( C2_core) does not undergo such a reaction because of the high deformation energy of the core required for the formation of C2_Py complex. 相似文献
47.
Ostrowska KM Malkin A Meade A O'Leary J Martin C Spillane C Byrne HJ Lyng FM 《The Analyst》2010,135(12):3087-3093
The main aetiology of cervical cancer is infection with high-risk human papillomavirus (HPV). Cervical cancer is almost 100% curable if detected in the early stages. Thus, information about the presence and levels of HPV in patient samples has high clinical value. As current screening methods, such as the Pap smear test, are highly subjective and in many cases show low sensitivity and specificity, new supportive techniques are desirable to improve the quality of cervical cancer screening. In this study, vibrational spectroscopic techniques (Raman and Fourier Transform Infra Red absorption) have been applied to the investigation of four cervical cancer cell lines: HPV negative C33A, HPV-18 positive HeLa with 20-50 integrated HPV copies per cell, HPV-16 positive SiHa with 1-2 integrated HPV strands per cell and HPV-16 positive CaSki containing 60-600 integrated HPV copies per cell. Results show that vibrational spectroscopic techniques can discriminate between the cell lines and elucidate cellular differences originating from proteins, nucleic acids and lipids. Similarities between C33A and SiHa cells were exhibited in the Raman and infrared spectra and were confirmed by Principal Component Analysis (PCA). Analysis of the biochemical composition of the investigated cells, with the aid of PCA, showed a clear discrimination between the C33A-SiHa group and HeLa and CaSki cell lines indicating the potential of vibrational spectroscopic techniques as a support to current methods for cervical cancer screening. 相似文献
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Rafał Głowacki Kamila Borowczyk Edward Bald Hieronim Jakubowski 《Analytical and bioanalytical chemistry》2010,396(6):2363-2366
A new assay for urinary homocysteine is described. The assay relies on an on-column derivatization with o-phthaldialdehyde, using a reversed-phase HPLC column and detection/quantification by fluorescence. The analysis time for
reduced and total homocysteine, including sample work-up, was 5 and 13 min, respectively. Quantification limit was 25 nM. 相似文献
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Kamila Kotrasova Eva Kormanikova 《Mathematical Methods in the Applied Sciences》2020,43(13):7664-7676
This paper presents the seismic response analysis of a cylindrical container made of laminated composite. The analytical homogenization is used for calculation of the material properties of unidirectional fiber-reinforced composite layer. Constitutive relations for laminate within the classical laminate theory are considered. Effective modulus of elasticity is obtained and put into a calculation of internal forces of the laminated composite cylindrical tank. The seismic analysis of liquid storage facilities has to have different approaches as the analysis of typical structures. Because of an earthquake, the hydrodynamic impulsive and convective pressures are generated in addition to hydrostatic pressure. The solved liquid-filled container made of the laminated composite was situated for the region of Slovak Republic and was analyzed in respect of Eurocode 8 recommendations. 相似文献
50.
Kamila Gawe? 《European Polymer Journal》2010,46(7):1475-1479
Novel polyelectrolytes have been synthesized by grafting sulfobetaine side chains onto hydroxypropylcellulose backbone. Polymers with various degrees of grafting have been obtained. The polymers do not interact with model anionic, cationic and zwitterionic surfactants as found in fluorescence studies using pyrene as a molecular probe. Dynamic light scattering (DLS) studies indicated that in the graft polymer solution two types of polymers are present. The films were formed from the grafted polymers. Using atomic force microscopy (AFM) technique it was found that they are resistant to the adhesion of proteins and can be used for the preparation of antiadhesive surfaces which may find biomedical applications. 相似文献