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1.
A perfluorosulfonic acid Nafion membrane has been studied with infrared spectroscopy. Infrared spectra of the membrane in acid form at the different degree of hydration were analysed in details and the conclusions about the state of sulfonic groups within clusters were drawn. The results indicate that in swollen samples in acid form hydrate structures involving dissociated sulfonic groups and water molecules are formed. These structures are analogous to those found in polystyrenesulfonic acid. With progressive drying of the Nafion membrane the network of hydrate structures breaks up and functional groups are transformed into their undissociated forms. 相似文献
2.
Andrzej Temeriusz Magdalena Rowińska Bogusława Piekarska‐Bartoszewicz Romana Anulewicz‐Ostrowska Michał K. Cyrański 《Journal of carbohydrate chemistry》2013,32(7):697-704
The title compound was synthesized starting from methyl 3,4,6‐tri‐O‐acetyl‐2‐acetamido‐2‐deoxy‐β‐D‐glucopyranoside, oxalyl chloride, and methyl 3,4,6‐tri‐O‐acetyl‐2‐amino‐2‐deoxy‐β‐D‐glucopyranoside. The crystal and molecular structure of the obtained imidazolidine‐4,5‐dione have been determined by X‐ray analysis as well as 1H and 13C NMR spectroscopy. 相似文献
3.
KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献
4.
We report a spatially resolved kinetic finite element model of parahydrogen-induced polarisation (PHIP) in a microfluidic chip that was calibrated using on-chip and off-chip NMR data. NMR spectroscopy has great potential as a read-out technique for lab-on-a-chip (LoC) devices, but is often limited by sensitivity. By integrating PHIP with a LoC device, a continuous stream of hyperpolarised material can be produced, and mass sensitivities of have been achieved. However, the yield and polarisation levels have so far been quite low, and can still be optimised. To facilitate this, a kinetic model of the reaction has been developed, and its rate constants have been calibrated using macroscopic kinetic measurements. The kinetic model was then coupled with a finite element model of the microfluidic chip. The model predicts the concentration of species involved in the reaction as a function of flow rate and position in the device. The results are in quantitative agreement with published experimental data. 相似文献
5.
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
6.
Joanna Wojnarska Katarzyna Ostrowska Marlena Gryl Katarzyna Marta Stadnicka 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(9):1228-1233
The carboxylic acid group is an example of a functional group which possess a good hydrogen‐bond donor (–OH) and acceptor (C=O). For this reason, carboxylic acids have a tendency to self‐assembly by the formation of hydrogen bonds between the donor and acceptor sites. We present here the crystal structure of N‐tosyl‐l ‐proline (TPOH) benzene hemisolvate {systematic name: (2S)‐1‐[(4‐methylbenzene)sulfonyl]pyrrolidine‐2‐carboxylic acid benzene hemisolvate}, C12H15NO4S·0.5C6H6, (I), in which a cyclic R22(8) hydrogen‐bonded carboxylic acid dimer with a strong O—(H)…(H)—O hydrogen bond is observed. The compound was characterized by single‐crystal X‐ray diffraction and NMR spectroscopy, and crystallizes in the space group I2 with half a benzene molecule and one TPOH molecule in the asymmetric unit. The H atom of the carboxyl OH group is disordered over a twofold axis. An analysis of the intermolecular interactions using the noncovalent interaction (NCI) index showed that the TPOH molecules form dimers due to the strong O—(H)…(H)—O hydrogen bond, while the packing of the benzene solvent molecules is governed by weak dispersive interactions. A search of the Cambridge Structural Database revealed that the disordered dimeric motif observed in (I) was found previously only in six crystal structures. 相似文献
7.
Daniel Długosz Malgorzata Pach Anna Zabrzeńska Monika Zegar Barbara J. Oleksyn Justyna Kalinowska-Tłuścik Katarzyna Ostrowska 《Monatshefte für Chemie / Chemical Monthly》2008,139(5):543-548
Bis(cycloamidine-2-yl)alkanes easily form bromide tribromide salts in the reduction-oxidation processes with bromine. Bis(tetrahydroimidazolium-2-yl)ethane
and bis(hexahydropyrimidinium-2-yl)-ethane bromide tribromides are such new convenient brominating agents for aromatic amides
in chemo- and regioselective electrophilic substitutions and α-bromination reactions.
Correspondence: Katarzyna Ostrowska, Department of Organic Chemistry, Jagiellonian University, R. Ingardena 3, PL-30060 Kraków,
Poland. 相似文献
8.
Pena Ruiz Tomas Drzewiecka Aleksandra Koziol Anna E. Fernandez Gomez Manuel Ostrowska Kinga Struga Marta Kossakowski Jerzy 《Structural chemistry》2012,23(5):1573-1584
Structural Chemistry - The structural analysis of khellinone and visnaginone indicated the planarity of the benzo[b]furan ring system. The oxygen or carbon atoms of the substituents, –OH,... 相似文献
9.
Ostrowska KM Garcia A Meade AD Malkin A Okewumi I O'Leary JJ Martin C Byrne HJ Lyng FM 《The Analyst》2011,136(7):1365-1373
Cervical cancer, a potentially preventable disease, has its main aetiology in infection by high risk human papillomavirus (HR-HPV). Approaches to improving cervical cancer screening and diagnostic methodologies include molecular biological analysis, targeting of biomarker proteins, but also exploration and implementation of new techniques such as vibrational spectroscopy. This study correlates the biomarker protein p16(INK4A) expression levels dependent on HPV copy number with the infrared absorption spectral signatures of the cervical cancer cell lines, HPV negative C33A, HPV-16 positive SiHa and CaSki and HPV-18 positive HeLa. Confocal fluorescence microscopy demonstrated that p16(INK4A) is expressed in all investigated cell lines in both nuclear and cytoplasmic regions, although predominantly in the cytoplasm. Flow cytometry was used to quantify the p16(INK4A) expression levels and demonstrated a correlation, albeit nonlinear, between the reported number of integrated HPV copies and p16(INK4A) expression levels. CaSki cells were found to have the highest level of expression, HeLa intermediate levels, and SiHa and C33A the lowest levels. FTIR spectra revealed differences in nucleic acid, lipid and protein signatures between the cell lines with varying HPV copy number. Peak intensities exhibited increasing tendency in nucleic acid levels and decreasing tendency in lipid levels with increasing HPV copy number, and although they were found to be nonlinearly correlated with the HPV copy number, their dependence on p16(INK4A) levels was found to be close to linear. Principal Component Analysis (PCA) of the infrared absorption spectra revealed differences between nuclear and cytoplasmic spectroscopic signatures for all cell lines, and furthermore clearly differentiated the groups of spectra representing each cell line. Finally, Partial Least Squares (PLS) analysis was employed to construct a model which can predict the p16(INK4A) expression level based on a spectral fingerprint of a cell line, demonstrating the diagnostic potential of spectroscopic techniques. 相似文献
10.