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201.
Alla Synytsya Miluše Judexová Tomáš Hrubý Michal Tatarkovič Michaela Miškovičová Luboš Petruželka Vladimír Setnička 《Analytical and bioanalytical chemistry》2013,405(16):5441-5453
Chiroptical methods are widely used in structural and conformational analyses of biopolymers. The application of these methods to investigations of biofluids would provide new avenues for the molecular diagnosis of protein-misfolding diseases. In this work, samples of human blood plasma and hen egg white were analyzed using a combination of conventional and chiroptical methods: ultraviolet absorption/electronic circular dichroism (UV/ECD), Fourier transform infrared absorption/vibrational circular dichroism (FTIR/VCD), and Raman scattering/Raman optical activity (Raman/ROA). For comparison, the main components of these substances—human serum albumin (HSA) and ovalbumin (Ova)—were also analyzed by these methods. The ultraviolet region of the ECD spectrum was analyzed using the CDNN CD software package to evaluate the secondary structures of the proteins. The UV/ECD, FTIR/VCD, and Raman/ROA spectra of the substances were quite similar to those of the corresponding major proteins, while some differences were also detected and explained. The conclusions drawn from the FTIR/VCD and Raman/ROA data were in good agreement with the secondary structures calculated from ECD. The results obtained in this work demonstrate that the chiroptical methods used here can be applied to analyze not only pure protein solutions but also more complex systems, such as biological fluids. Figure
Analysis of human blood plasma and hen egg white by ECD, VCD and ROA. 相似文献
202.
Niga P King W Hedberg J Johnson CM Frey JG Rutland MW 《Physical chemistry chemical physics : PCCP》2011,13(17):7930-7938
The surface of aqueous solutions of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) has been studied using the surface sensitive technique vibrational sum frequency spectroscopy (VSFS). The NO, CN, COC and CH vibrational modes of these compounds at the air-water interface as well as OH vibrational modes of the surface water hydrating this compound have been targeted in order to obtain molecular information about arrangement and conformation of the adsorbed crown ether molecules at the air-water interface. The CH(2) vibrational modes of crown ethers have been identified and found to be split due to interaction with ether oxygen. The spectra provide evidence for the existence of a protonated crown complex moiety at the surface leading to the appearance of strongly ordered water species. The interfacial water species are influenced by the resulting charged interface and by the strong Zundel polarizability due to tunneling of the proton species between equivalent sites within the crown ring. 相似文献
203.
Păușescu Iulia Todea Anamaria Badea Valentin Peter Francisc Medeleanu Mihai Ledeți Ionuț Vlase Gabriela Vlase Titus 《Journal of Thermal Analysis and Calorimetry》2020,141(3):999-1008
Journal of Thermal Analysis and Calorimetry - Intelligent food packaging systems register and monitor food quality through data carriers, sensors or indicators. Food spoilage often leads to pH... 相似文献
204.
Todea Anamaria Aparaschivei Diana Bîtcan Ioan Ledeți Ionuț Valentin Bandur Geza Péter Francisc Nagy Lajos Kéki Sándor Biró Emese 《Journal of Thermal Analysis and Calorimetry》2020,141(3):1017-1026
Journal of Thermal Analysis and Calorimetry - The thermal behavior of co-oligomers of ε-caprolactone (ECL) with gluconolactone, compared to the ε-caprolactone oligomer, has been assessed... 相似文献
205.
206.
Petru Jitaru 《Analytica chimica acta》2003,489(1):45-57
A simple, rapid and accurate method on the basis of multicapillary gas chromatography (MCGC) combined with inductively coupled plasma-time-of-flight mass spectrometry (ICP-TOFMS) was developed for speciation analysis of methylmercury (MeHg+) and inorganic mercury (Hg2+). The potential of the ICP-TOFMS for transient multi-isotope detection of very short signals (peak width of 0.4 s at half peak height) was evaluated. Two injection systems (purge-and-trap (PTI) and split (SI) injections) were compared in terms of species separation resolution and transient signal profile. Using purge-and-trap injection, after in situ derivatization of the ionic mercury species with sodium tetraethylborate, a baseline separation of MeHg+ and Hg2+ was achieved within a chromatographic run of <35 s. To correct for matrix-induced ion signal variation and instrumental drift, propylmercury (PrHg+) was used as internal standard. Detection limits of 16 and 257 fg g−1 for MeHg+ (as Hg) and Hg2+, respectively, were achieved. The analytical precision (R.S.D. (%)) for 10 successive injections of a standard mixture containing 10 pg MeHg+ (as Hg) and Hg2+ was 1.2% for MeHg+ and 4.1% for Hg2+. The method was validated by analysis of two biological certified reference materials (CRM): a dogfish muscle (DORM-2) and a freeze-dried tuna fish (CRM 464). 相似文献
207.
Yan Zhang Jiande Wang Petru Apostol Darsi Rambabu Alae Eddine Lakraychi Xiaolong Guo Xiaozhe Zhang Xiaodong Lin Shubhadeep Pal Vasudeva Rao Bakuru Xiaohua Chen Alexandru Vlad 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310033
A new phosphonate-based anionic bimetallic organic framework, with the general formula of A4−Zn−DOBDP (wherein A is Li+ or Na+, and DOBDP6− is the 2,5-dioxido-1,4-benzenediphosphate ligand) is prepared and characterized for energy storage applications. With four alkali cations per formula unit, the A4−Zn−DOBDP MOF is found to be the first example of non-solvated cation conducting MOF with measured conductivities of 5.4×10−8 S cm−1 and 3.4×10−8 S cm−1 for Li4- and Na4- phases, indicating phase and composition effects of Li+ and Na+ shuttling through the channels. Three orders of magnitude increase in ionic conductivity is further attained upon solvation with propylene carbonate, placing this system among the best MOF ionic conductors at room temperature. As positive electrode material, Li4−Zn−DOBDP delivers a specific capacity of 140 mAh g−1 at a high average discharge potential of 3.2 V (vs. Li+/Li) with 90 % of capacity retention over 100 cycles. The significance of this research extends from the development of a new family of electroactive phosphonate-based MOFs with inherent ionic conductivity and reversible cation storage, to providing elementary insights into the development of highly sought yet still evasive MOFs with mixed-ion and electron conduction for energy storage applications. 相似文献
208.
Georgiana Ioana Potra Cicalu Petru Aurel Babes Horia Calniceanu Adelina Popa Gabriela Ciavoi Gilda Mihaela Iova Mariana Ganea Ioana Scrobot 《Molecules (Basel, Switzerland)》2021,26(22)
Periodontal disease and diabetes mellitus are two pathologies that are extremely widespread worldwide and share the feature of chronic inflammation. Carvacrol is a phenolic monoterpenoid, produced by a variety of herbs, the most well-known of which is Origanum vulgare. Magnolol is a traditional polyphenolic compound isolated from the stem bark of Magnolia officinalis, mainly used in Chinese medicine. The purpose of this paper is to review the therapeutic properties of these bioactive compounds, in the treatment of periodontitis and diabetes. Based on our search strategy we conducted a literature search in the PubMed and Google Scholar databases to identify studies. A total of one hundred eighty-four papers were included in the current review. The results show that carvacrol and magnolol have anti-inflammatory, antioxidant, antimicrobial, anti-osteoclastic, and anti-diabetic properties that benefit both pathologies. Knowledge of the multiple activities of carvacrol and magnolol can assist with the development of new treatment strategies, and the design of clinical animal and human trials will maximize the potential benefits of these extracts in subjects suffering from periodontitis or diabetes. 相似文献