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961.
Studies on sorption of diammine Au(I) cationic complex from ammoniacal solutions of varying composition into pure and modified with butylamine α‐ZrP have been performed in the temperature change from 40 to 80°C. Experimental results have been discussed in terms of first order reaction kinetics. The activation energies of sorption of Au(I) into pure and modified α‐ZrP were found to be equal to 28 (± 3) and 84 (± 7) kJ?mol?1, respectively. The effects of concentrations of ammonia, ammonium sulfate and Cu(II) were also examined. The kinetic parameters of sorption of tetraammine Cu(II) complex from ammoniacal solutions into modified α‐ZrP were also determined. 相似文献
962.
Wojciech Bocian Beata Naumczuk Magdalena Urbanowicz Jerzy Sitkowski Anna Bierczyska-Krzysik Elbieta Bednarek Katarzyna Wiktorska Magorzata Milczarek Lech Kozerski 《International journal of molecular sciences》2021,22(14)
The compounds 7-ethyl-9-(N-methylamino)methyl-10-hydroxycamptothecin (2) and 7-ethyl-9-(N-morpholino)methyl-10-hydroxycamptothecin (3) are potential topoisomerase I poisons. Moreover, they were shown to have favorable anti-neoplastic effects on several tumor cell lines. Due to these properties, the compounds are being considered for advancement to the preclinical development stage. To gain better insights into the molecular mechanism with the biological target, here, we conducted an investigation into their interactions with model nicked DNA (1) using different techniques. In this work, we observed the complexity of the mechanism of action of the compounds 2 and 3, in addition to their decomposition products: compound 4 and SN38. Using DOSY experiments, evidence of the formation of strongly bonded molecular complexes of SN38 derivatives with DNA duplexes was provided. The molecular modeling based on cross-peaks from the NOESY spectrum also allowed us to assign the geometry of a molecular complex of DNA with compound 2. Confirmation of the alkylation reaction of both compounds was obtained using MALDI–MS. Additionally, in the case of 3, alkylation was confirmed in the recording of cross-peaks in the 1H/13C HSQC spectrum of 13C-enriched compound 3. In this work, we showed that the studied compounds—parent compounds 2 and 3, and their potential metabolite 4 and SN38—interact inside the nick of 1, either forming the molecular complex or alkylating the DNA nitrogen bases. In order to confirm the influence of the studied compounds on the topoisomerase I relaxation activity of supercoiled DNA, the test was performed based upon the measurement of the fluorescence of DNA stain which can differentiate between supercoiled and relaxed DNA. The presented results confirmed that studied SN38 derivatives effectively block DNA relaxation mediated by Topo I, which means that they stop the machinery of Topo I activity. 相似文献
963.
Hanna Grajek Jacek Kubicki Ignacy Gryczyski Jerzy Karolczak Grayna urkowska Agnieszka I. Piotrowicz-Cielak Piotr Bojarski 《International journal of molecular sciences》2021,22(14)
The results of time-resolved fluorescence measurements of flavin mononucleotide (FMN) in rigid polyvinyl alcohol films (PVA) demonstrate that fluorescence intensity decays are strongly accelerated in the presence of fluorescent dimers and nonradiative energy transfer processes. The fluorescence decay originating both from H and J dimer states of FMN was experimentally observed for the first time. The mean fluorescence lifetimes for FMN dimers were obtained: = 2.66 ns (at λexc = 445 nm) and = 2.02 (at λexc = 487 nm) at λobs = 600 nm and T = 253 K from H and J state of dimers, respectively. We show that inhomogeneous orientational broadening of energy levels (IOBEL) affects the shape of the fluorescence decay and leads to the dependence of the average monomer fluorescence lifetime on excitation wavelength. IOBEL affected the nonradiative energy transfer and indicated that different flavin positioning in the protein pocket could (1) change the spectroscopic properties of flavins due to the existence of “blue” and “red” fluorescence centers, and (2) diminish the effectiveness of energy transfer between FMN molecules. 相似文献
964.
Jan Jankowski Zenon Zdunczyk Dariusz Mikulski Jerzy Juskiewicz Jakub Naczmanski Janusz F. Pomianowski Przemysław Zdunczyk 《European Journal of Lipid Science and Technology》2012,114(9):1025-1035
The objective of this study was to determine the effect of diets with a different n‐6/n‐3 PUFAs ratio (7.31, 4.43, and 0.99), resulting from the addition of different dietary oils: soybean, rapeseed, and linseed (diets S, R, and L, respectively), on the fatty acid (FA) profile, oxidative status, and sensory properties of turkey breast meat. After 15 wk of feeding, breast meat yield and chemical properties of the meat were similar in all groups. Raw breast meat of R turkeys had a significantly higher content of all‐trans‐retinol and α‐tocopherol, compared with S and L. The physicochemical properties of breast meat, including pH, color, drip loss, and cooking loss, did not differ significantly. Cooked meat samples differed significantly with respect to the concentrations of oleic acid, linoleic acid (S and R>L), and linolenic acid (S and R<L). Compared with S and R, breast meat of L turkeys was characterized by higher concentrations of total PUFAs (35.1 vs. 30.1 and 29.3%), a significantly lower n‐6/n‐3 PUFAs ratio (1.51 vs. 5.43 and 5.07%) and a higher thiobarbituric acid reactive substances content (TBARS; 31.9 vs. 26.4 and 26.7 nmol/g). After 4 months of deep‐freeze storage the n‐6/n‐3 PUFAs ratio did not deteriorate. It may be concluded that replacing soybean oil with linseed oil, but not with rapeseed oil, increased the proportion of PUFAs in the total FAs pool and improved the n‐6/n‐3 PUFAs ratio, yet it also adversely affected the sensory properties and oxidative stability of meat. Both raw and stored breast meat from L turkeys was susceptible to oxidative changes, as manifested by the significantly higher TBARS concentrations (17.07 and 81.06) compared with those of the S group (10.91 and 53.00 nmol/g, respectively). Practical applications: Studies investigating the possibility of increasing the health benefits of poultry meat have been performed mostly on broilers, while the problem remains poorly researched in turkeys. Our findings show that linseed oil, in contrast to rapeseed oil, is a good source of PUFAs, in particular n‐3 PUFAs, that can be effectively transferred from feed to carcass lipids. However, desirable changes in the fatty acid profile are accompanied by increased susceptibility to lipid oxidation and deterioration of the sensory properties of meat. Thus, the linseed oil content of turkey diets should be reduced, or diets supplemented with linseed oil should be fed for shorter periods of time to alleviate the negative effects of linseed oil on the sensory attributes and oxidative status of meat. 相似文献
965.
966.
Jerzy Dryzek 《Tribology Letters》2010,40(1):175-180
The report about subsurface zone (SZ) created during dry sliding in pure bismuth is presented. The positron lifetime measurements
revealed the well defined subsurface zone where the concentration of created during sliding vacancy clusters decreases exponentially
with the depth from the worn surface increases. The experimental results are quite well described by the two state trapping
model which allows to determine the positron trapping rate and hence deduce about the depth dependency of vacancy voids concentration.
Despite of the low recrystallization temperature ca. 115 °C in this semimetal, determined also by the positron lifetime measurements, no significant effect of temperature rise
due to sliding on the SZ constitution is observed. 相似文献
967.
G Jarzyńska A Chojnacka A Dryżałowska IC Nnorom J Falandysz 《Journal of food science》2012,77(9):H202-H206
Abstract: Yellow‐cracking Bolete (Xerocomus subtomentosus) mushrooms and soil were collected from Note? Forest–a large forested enclave in western part of Poland. Mercury was determined by cold vapour atomic absorption spectroscopy and the other elements by inductively coupled plasma atomic emission spectroscopy. K, P, and Mg were particularly abundant, with mean values of 46000, 8400, and 1100 mg/kg dry weight (dw) in caps followed by Na, Rb, Zn, and Ca with mean concentrations of 580, 350, 200, and 170 mg/kg dw, respectively. In descending order, the mean concentrations of Fe, Al, Cu, and Mn were 52, 49, 46, and 14 mg/kg dw, while the mean for the remaining elements was around 1.0 mg/kg dw or less. The elements such as Ca, Cu, Hg, K, Mg, Na, P, Rb, Zn, Ag, Cd, and Ni were accumulated (with bioconcentration factor (BCF) > 1), while Al, Ba, Fe, Mn, Sr, Co, Cr, and Pb were excluded (BCF < 1) in the fruiting bodies. The Pb and Cd content did not exceed the maximum levels set by the EU for cultivated mushrooms. Mercury in a conventional meal (300 g) portion of Yellow‐cracking Bolete was far below the provisionally tolerable weekly intake of 0.004 mg/kg body weight (bw) as reevaluated recently by WHO. Practical Application: The method presented in this study allows one to determine the content of 20 elements (Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, and Zn) in caps and stipes of Yellow‐cracking Bolete (Xerocomus subtomentosus) mushrooms and soil samples collected from Poland. This study has revealed that the total Cd, Hg, and Pb dose provided to human body due to consumption of Yellow‐cracking Bolete does not pose threat to a consumer's health. 相似文献
968.
Naveed Ahsan Christer Svensson Rashad Ramzan Jerzy Dabrowski Aziz Ouacha Carl Samuelsson 《Analog Integrated Circuits and Signal Processing》2012,70(1):79-90
This paper presents the design and implementation of a low power, highly linear, wideband RF front-end in 90 nm CMOS. The
architecture consists of an inverter-like common gate low noise amplifier followed by a passive ring mixer. The proposed architecture
achieves a high linearity in a wide band (0.5–6 GHz) at very low power. Therefore, it is a suitable choice for software defined
radio (SDR) receivers. The chip measurement results indicate that the inverter-like common gate input stage has a broadband
input match achieving S11 below −8.8 dB up to 6 GHz. The measured single sideband noise figure at an LO frequency of 3 GHz
and an IF of 10 MHz is 6.25 dB. The front-end achieves a voltage conversion gain of 4.5 dB at 1 GHz with 3 dB bandwidth of
more than 6 GHz. The measured input referred 1 dB compression point is +1.5 dBm while the IIP3 is +11.73 dBm and the IIP2
is +26.23 dBm respectively at an LO frequency of 2 GHz. The RF front-end consumes 6.2 mW from a 1.1 V supply with an active
chip area of 0.0856 mm2. 相似文献
969.
970.
Wojciech Knap Mikhail Dyakonov Dominique Coquillat Frederic Teppe Nina Dyakonova Jerzy Łusakowski Krzysztof Karpierz Maciej Sakowicz Gintaras Valusis Dalius Seliuta Irmantas Kasalynas Abdelouahad El Fatimy Y. M. Meziani Taiichi Otsuji 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(12):1319-1337
Resonant frequencies of the two-dimensional plasma in FETs increase with the reduction of the channel dimensions and can reach the THz range for sub-micron gate lengths. Nonlinear properties of the electron plasma in the transistor channel can be used for the detection and mixing of THz frequencies. At cryogenic temperatures resonant and gate voltage tunable detection related to plasma waves resonances is observed. At room temperature, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector. We present the main theoretical and experimental results on THz detection by FETs in the context of their possible application for THz imaging. 相似文献