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11.
ule Hilal Attar Muhammet Ali Gündeli Ipek Urün Salih Kafkas Nesibe Ebru Kafkas Sezai Ercisli Chunfeng Ge Jiri Mlcek Anna Adamkova 《Molecules (Basel, Switzerland)》2022,27(3)
Pitaya is one of the most preferred and produced tropical fruit species recently introduced to the Mediterrranean region in Turkey. Due to its nutritional fruits with high economic value, the popularity of pitaya increases steadily in Turkey as an alternative crop. No detailed nutritional analysis has been undertaken in Turkey so far on fruits of the pitaya species. In this study, we determined and compared some nutritional parameters in fruit flesh of two pitaya (dragon fruit) species (Hylocereus polyrhizus: Siyam and Hylocereus undatus: Vietnam Jaina) grown in the Adana province located in the eastern Mediterranean region in Turkey. The individual sugars, antioxidant activity, total phenolic content, phenolic compounds and volatiles were determined for the first time in Turkey on two pitaya species. The results showed that total phenol content and antioxidant capacity are notably higher in red-fleshed fruits than white-fleshed ones and the predominant phenolic compound in fruits of both species was quercetin. The total sugar content and most of the phenolic compounds in fruits of two pitaya species were similar. A total of 51 volatile compounds were detected by using two Solid Phase Micro Extraction (SPME) fibers, coupled with Gas Chromatography Mass Spectrometry (GC-MS) techniques, and more volatile compounds were presented in the white-fleshed species. Total phenolic content (TPC) of the red-fleshed and white-fleshed pitaya species were 16.66 and 17.11 mg GAE/100 g FW (fresh weight). This study provides a first look at the biochemical comparison of red-fleshed and white-fleshed pitaya species introduced and cultivated in Turkey. The results also showed, for the first time, the biochemical content and the potential health benefit of Hylocereus grown in different agroecological conditions, providing important information for pitaya researchers and application perspective. 相似文献
12.
Fuxiang Ji Feng Wang Libor Kobera Sabina Abbrent Jiri Brus Weihua Ning Feng Gao 《Chemical science》2021,12(5):1730
Although lead-free halide double perovskites are considered as promising alternatives to lead halide perovskites for optoelectronic applications, state-of-the-art double perovskites are limited by their large bandgap. The doping/alloying strategy, key to bandgap engineering in traditional semiconductors, has also been employed to tune the bandgap of halide double perovskites. However, this strategy has yet to generate new double perovskites with suitable bandgaps for practical applications, partially due to the lack of fundamental understanding of how the doping/alloying affects the atomic-level structure. Here, we take the benchmark double perovskite Cs2AgInCl6 as an example to reveal the atomic-level structure of double perovskite alloys (DPAs) Cs2AgIn1−xFexCl6 (x = 0–1) by employing solid-state nuclear magnetic resonance (ssNMR). The presence of paramagnetic alloying ions (e.g. Fe3+ in this case) in double perovskites makes it possible to investigate the nuclear relaxation times, providing a straightforward approach to understand the distribution of paramagnetic alloying ions. Our results indicate that paramagnetic Fe3+ replaces diamagnetic In3+ in the Cs2AgInCl6 lattice with the formation of [FeCl6]3−·[AgCl6]5− domains, which show different sizes and distribution modes in different alloying ratios. This work provides new insights into the atomic-level structure of bandgap engineered DPAs, which is of critical significance in developing efficient optoelectronic/spintronic devices.Through Fe3+-alloying, the bandgap of benchmark double perovskite Cs2AgInCl6 can be tuned from 2.8 eV to 1.6 eV. The atomic-level structure of Cs2AgIn1−xFexCl6 was revealed by solid-state nuclear magnetic resonance (ssNMR). 相似文献
13.
Luk Petera Klaudia Mrazikova Lukas Nejdl Kristyna Zemankova Marketa Vaculovicova Adam Pastorek Svatopluk Civis Petr Kubelik Alan Heays Giuseppe Cassone Jiri Sponer Martin Ferus Judit Sponer 《Molecules (Basel, Switzerland)》2021,26(8)
Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers. 相似文献
14.
Werzer O Boucher N de Silva JP Gbabode G Geerts YH Konovalov O Moser A Novak J Resel R Sferrazza M 《Langmuir : the ACS journal of surfaces and colloids》2012,28(22):8530-8536
Temperature dependent structural and morphological investigations on semiconducting dioctyl-terthiophene (DOTT) thin films prepared on silica surfaces reveals the coexistence of surface induce order and distinct crystalline/liquid crystalline bulk polymorphs. X-ray diffraction and scanning force microscopy measurements indicate that at room temperature two polymorphs are present: the surface induced phase grows directly on the silica interface and the bulk phase on top. At elevated temperatures the long-range order gradually decreases, and the crystal G (340 K), smectic F (348 K), and smectic C (360 K) phases are observed. Indexation of diffraction peaks reveals that an up-right standing conformation of DOTT molecules is present within all phases. A temperature stable interfacial layer close to the silica-DOTT interface acts as template for the formation of the different phases. Rapid cooling of the DOTT sample from the smectic C phase to room temperature results in freezing into a metastable crystalline state with an intermediated unit cell between the room temperature crystalline phase and the smectic C phase. The understanding of such interfacial induced phases in thin semiconducting liquid crystal films allows tuning of crystallographic and therefore physical properties within organic thin films. 相似文献
15.
Dr. Tana Koudelakova Dr. Radka Chaloupkova Dr. Jan Brezovsky Dr. Zbynek Prokop Dr. Eva Sebestova Dr. Martin Hesseler Dr. Morteza Khabiri Maryia Plevaka Daryna Kulik Dr. Ivana Kuta Smatanova Dr. Pavlina Rezacova Dr. Rudiger Ettrich Prof. Uwe T. Bornscheuer Prof. Jiri Damborsky 《Angewandte Chemie (International ed. in English)》2013,52(7):1959-1963
16.
Francine Vinette Jiri Cizek Edward R. Vrscay 《International journal of quantum chemistry》1987,32(6):663-667
The upper and lower bounds of a harmonic oscillator with an octic perturbation are studied with the use of renormalized inner projection. It is shown that this relatively simple technique works even in the infinite coupling constant limit. Symbolic computation is very convenient and useful in these types of problems, where only a finite number of operations are required. 相似文献
17.
Dimitris I. Ioannou Prof. Dr. Luca Capaldo Jiri Sanramat Prof. Dr. Joost N. H. Reek Prof. Dr. Timothy Noël 《Angewandte Chemie (International ed. in English)》2023,62(52):e202315881
Electrophotocatalytic transformations are garnering attention in organic synthesis, particularly for accessing reactive intermediates under mild conditions. Moving these methodologies to continuous-flow systems, or flow ElectroPhotoCatalysis (f-EPC), showcases potential for scalable processes due to enhanced irradiation, increased electrode surface, and improved mixing of the reaction mixture. Traditional methods sequentially link photochemical and electrochemical reactions, using flow reactors connected in series, yet struggle to accommodate reactive transient species. In this study, we introduce a new flow reactor concept for electrophotocatalysis (EPC) that simultaneously utilizes photons and electrons. The reactor is designed with a transparent electrode and employs cost-effective materials. We used this technology to develop an efficient process for electrophotocatalytic heteroarylation of C(sp3)−H bonds. Importantly, the same setup can also facilitate purely electrochemical and photochemical transformations. This reactor represents a significant advancement in electrophotocatalysis, providing a framework for its application in flow for complex synthetic transformations. 相似文献
18.
Sylvie Skalickova Pavel Horky Veronika Mlejnkova Jiri Skladanka Bozena Hosnedlova Branislav Ruttkay‐Nedecky Carlos Fernandez Rene Kizek 《Chemical record (New York, N.Y.)》2021,21(1):17-28
Polysaccharide nanoparticles are promising materials in the wide range of disciplines such as medicine, nutrition, food production, agriculture, material science and others. They excel not only in their non‐toxicity and biodegradability but also in their easy preparation. As well as inorganic particles, a protein corona (PC) around polysaccharide nanoparticles is formed in biofluids. Moreover, it has been considered that the overall response of the organism to nanoparticles presence depends on the PC. This review summarises scientific publications about the structural chemistry of polysaccharide nanoparticles and their impact on theranostic applications. Three strategies of implementation of the PC in theranostics have been discussed: I) Utilisation of the PC in therapy; II) How the composition of the PC is analysed for specific disease markers; III) How the formed PC can interact with the immune system and enhances the immunomodulation or immunoelimination. Thus, the findings from this review can contribute to improve the design of drug delivery systems. However, it is still necessary to elucidate the mechanisms of nano‐bio interactions and discover new connections in nanoscale research. 相似文献
19.
Uranium is determined via its 239U nuclide (74.0 keV, t = 23.5 min) in natural waters down to 0.03 ng U ml-1 after preconcentration with activated carbon and oxine; 30-min irradiation and counting times are used. No preconcentration is required for samples containing more than 4 ng U ml-1 with 10-min irradiation and counting times. Uranium in urine can be determined under a boron shield at the 5 ng ml-1 level after 30-min irradiation and counting. 相似文献
20.
Ab initio investigations at the RHF and CI levels have been carried out on a section of the potential energy surface of the Rydberg 3s3A″2 state of NH3 leading to dissociation into NH2(2B1) and H(2S). It was found that the barrier towards dissociation is due to a Rydberg-valence transformation. The barrier height calculated with the CI wavefunction is significantly smaller than at the RHF level The results may explain the difficulties associated with experimental observation of the 3s3A″2 state. 相似文献