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991.
Adam Gryff‐Keller Przemysław Szczeciński Anna Kraska‐Dziadecka 《Journal of Physical Organic Chemistry》2011,24(3):249-256
2‐[2‐Nitro‐4‐(trifluoromethyl)benzoyl]cyclohexane‐1,3‐dione (NTBC) is an active component of nitisinone, a medicine against tyrosinemia type I. Using 1H, 13C and 19F NMR spectroscopy it has been found that in the urine of patients treated with nitisinone two compounds possessing CF3 group are always present. They have been isolated by using TLC technique and identified as 4‐hydroxy‐2‐[2‐nitro‐4‐(trifluoromethyl)benzoyl]cyclohexane‐1,3‐dione and 5‐hydroxy‐2‐[2‐nitro‐4‐(trifluoromethyl)benzoyl]cyclohexane‐1,3‐dione, the latter being previously unknown. The constitution, tautomerism and stereochemistry of these compounds have been thoroughly investigated using 1H and 13C NMR spectroscopy supported by theoretical calculations. Molecular structures have been optimized using density functional theory (DFT) with PBE1PBE functional and 6‐31G* basis set. In NMR parameter calculations, the larger 6‐311++G(2d,p) basis set has been used. At both calculation stages, the polarizable continuum model of the solvent has been employed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
992.
Stanis?aw L. Ba?ański 《General Relativity and Gravitation》2011,43(12):3693-3703
It is my great pleasure to dedicate this article to Josh Goldberg, a long-standing friend of mine. In terms of special theory
of relativity, a discussion of a geometric model representing a rigidly rotating circle of material particles is given. It
is shown that the ratio of the proper length of the spatial circumference of the circle to its radius is the same as in the
case of a circle that is at rest relative to a global inertial frame of reference when the circumference is measured in terms
of invariants determined by a set of local inertial observers who are momentarily comoving with the particles at equal values
of their proper times which are synchronized in turn by every pair of neighbouring observers one after the other. 相似文献
993.
Judyta Cielecka-Piontek Przemysław Zalewski Bolesław Barszcz Kornelia Lewandowska Magdalena Paczkowska 《Chromatographia》2013,76(7-8):381-386
A inexpensive and rapid isocratic LC method has been developed for the quantitative determination of tebipenem—a new β-lactam antibiotic. Stress degradation studies were performed on tebipenem in acidic (0.2 N hydrochloric acid) and basic (0.02 N sodium hydroxide) solutions, in a solution with oxidizing agent (3 % hydrogen peroxide), and in the solid state, during thermolysis and photolysis. For a chromatographic separation of tebipenem and its degradation products, a C-18 stationary phase and 12 mM ammonium acetate-acetonitrile (96:4 v/v) were used. A quantitative determination of tebipenem was carried out by using a PDA detector at 298 nm, with a flow rate of 1.2 mL min?1. The linear regression analysis for the calibration plots showed a good linear relationship (r = 0.999) in the concentration range 0.041–0.240 mg mL?1. The method demonstrated good precision (1.14–1.96 % RSD) and recovery (99.60–101.90 %). The limits of detection and quantitation were 9.69 and 29.36 μg mL?1, respectively. The analysis of tebipenem reactivity was supported by quantum chemical calculations based on the density functional theory (DFT). The analysis of the electron density of the HOMO and LUMO of tebipenem suggested the possibility of electron transport in the molecule during the degradation of bi-cyclic 4:5 fused penem rings. 相似文献
994.
Zdzisław Brzeźniak Utpal Manna Akash Ashirbad Panda 《Journal of Differential Equations》2019,266(10):6204-6283
In this work we consider a stochastic evolution equation which describes the system governing the nematic liquid crystals driven by a pure jump noise in the Marcus canonical form. The existence of a martingale solution is proved for both 2D and 3D cases. The construction of the solution relies on a modified Faedo–Galerkin method based on the Littlewood–Paley-decomposition, compactness method and the Jakubowski version of the Skorokhod representation theorem for non-metric spaces. We prove that in the 2-D case the martingale solution is pathwise unique and hence deduce the existence of a strong solution. 相似文献
995.
Numerical Algorithms - In this paper, an abstract evolutionary hemivariational inequality with a history-dependent operator is studied. First, a result on its unique solvability and solution... 相似文献
996.
997.
Sylwia Modrzycka Sonia Kot Stphanie G. I. Polderdijk Ty E. Adams Stanisaw Potoczek James A. Huntington Paulina Kasperkiewicz Marcin Drg 《Chemical science》2022,13(23):6813
Activated protein C (APC), thrombin, and factor (f) Xa are vitamin K-dependent serine proteases that are key factors in blood coagulation. Moreover, they play important roles in inflammation, apoptosis, fibrosis, angiogenesis, and viral infections. Abnormal activity of these coagulation factors has been related to multiple conditions, such as bleeding and thrombosis, Alzheimer''s disease, sepsis, multiple sclerosis, and COVID-19. The individual activities of APC, thrombin, and fXa in coagulation and in various diseases are difficult to establish since these proteases are related and have similar substrate preferences. Therefore, the development of selective chemical tools that enable imaging and discrimination between coagulation factors in biological samples may provide better insight into their roles in various conditions and potentially aid in the establishment of novel diagnostic tests. In our study, we used a large collection of unnatural amino acids, and this enabled us to extensively explore the binding pockets of the enzymes'' active sites. Based on the specificity profiles obtained, we designed highly selective substrates, inhibitors, and fluorescent activity-based probes (ABPs) that were used for fast, direct, and simultaneous detection of APC, thrombin, and fXa in human plasma.Using a collection of natural and unnatural amino acids, we synthesized a set of fluorescent activity-based probes for the fast, direct, and simultaneous detection of coagulation factors in human plasma. 相似文献
998.
Robert Hildebrandt Krystian Skubacz Izabela Chmielewska Zdzisaw Dyduch Aleksandra Zgrska Adam Smoliski 《Molecules (Basel, Switzerland)》2022,27(12)
Aerosol transmission constitutes one of the major transmission routes of the SARS-CoV-2 pathogen. Due to the pathogen’s properties, research on its airborne transmission has some limitations. This paper focuses on silica nanoparticles (SiO2) of 40 and 200 nm sizes as the physicochemical markers of a single SARS-CoV-2 particle enabling experiments on the transmission of bioaerosols in public spaces. Mixtures of a determined silica concentration were sprayed on as an aerosol, whose particles, sedimented on dedicated matrices, were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Since it was not possible to quantitatively identify the markers based on the obtained images, the filters exposed with the AirSampler aspirator were analyzed based on inductively coupled plasma optical emission spectroscopy (ICP-OES). The ICP-OES method enabled us to determine the concentration of silica after extracting the marker from the filter, and consequently to estimate the number of markers. The developed procedure opens up the possibility of the quantitative estimation of the spread of the coronavirus, for example in studies on the aerosol transmission of the pathogen in an open environment where biological markers—surrogates included—cannot be used. 相似文献
999.
Aleksandra Stegliska Katarzyna Pielech-Przybylska Regina Janas Mieczysaw Grzesik Sebastian Borowski Dorota Krgiel Beata Gutarowska 《Molecules (Basel, Switzerland)》2022,27(12)
The feasibility of early disease detection in potato seeds storage monitoring of volatile organic compounds (VOCs) and plant physiological markers was evaluated using 10 fungal and bacterial pathogens of potato in laboratory-scale experiments. Data analysis of HS-SPME-GC-MS revealed 130 compounds released from infected potatoes, including sesquiterpenes, dimethyl disulfide, 1,2,4-trimethylbenzene, 2,6,11-trimethyldodecane, benzothiazole, 3-octanol, and 2-butanol, which may have been associated with the activity of Fusarium sambucinum, Alternaria tenuissima and Pectobacterium carotovorum. In turn, acetic acid was detected in all infected samples. The criteria of selection for volatiles for possible use as incipient disease indicators were discussed in terms of potato physiology. The established physiological markers proved to demonstrate a negative effect of phytopathogens infecting seed potatoes not only on the kinetics of stem and root growth and the development of the entire root system, but also on gas exchange, chlorophyll content in leaves, and yield. The negative effect of phytopathogens on plant growth was dependent on the time of planting after infection. The research also showed different usefulness of VOCs and physiological markers as the indicators of the toxic effect of inoculated phytopathogens at different stages of plant development and their individual organs. 相似文献
1000.