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41.
Ewa Skrzypczak-Jankun Hanna Małuszyńska Anna Perkowska Zygmunt Kałuski 《Journal of chemical crystallography》1980,10(3-4):67-74
The formula of the title compound is C16H27ClN2O5,MW = 362.9 orthorhombic,P212121,a = 8.403(1),b= 13.133(1),c= 15.972(2) Å,Z = 4,D
x
= 1.37 g cm–3, (CuK) = 2.2 mm-1. The lupanine skeleton has atrans-trans configuration. The ringA has a half-chair conformation, theB andD rings adopt a chair form, and theC ring forms a boat. The lupanine cations are linked together by the intermolecular hydrogen bonds forming infinite chains alongb. The N(16) ... O(C2) distance is 2.763(7) Å. 相似文献
42.
We describe a method to improve the resolution of donor-to-acceptor distance distributions in molecules which are flexing on the timescale of the fluorescence lifetime. We measured the timedependent donor decays of two donor (D)-acceptor (A) pairs, where the donor lifetimes were substantially different. The donors were an indole residue (5.7 ns) and a naphthalene residue (24.4 ns). The same dansyl acceptor was used for both D-A pairs. The donor decays are complex due to both a distribution of D-A distances and D-A diffusion. Using the donor decay data for each D-A pair alone, it is difficult to resolve both the distance distribution and the D-to-A diffusion coefficient. However, these values are unambiguously recovered from global analysis of the data from both D-A pairs. The increased resolution from the global analysis is apparently the result of the complementary information content of the data for each D-A pair. The shorter-lived indole donor provides more information on the time-zero distance distribution because there is less time for D-A diffusion, and the longer-lived naphthyl donor is quenched to a greater extent than indole due to the longer time for diffusion-enhanced energy transfer. Simulations were also used to demonstrate the increased resolution of global analysis with different lifetime donors to obtain distance distribution parameters in the presence of D-A diffusion. 相似文献
43.
Zhang J Gryczynski I Gryczynski Z Lakowicz JR 《The journal of physical chemistry. B》2006,110(18):8986-8991
Silica beads with average diameters of 40-600 nm were prepared, and Ru(bpy)3(2+) complexes were incorporated into the beads. These beads were coated by silver layer by layer to generate porous but continuous metal nanoshells. The thicknesses of these metal shells were 5-50 nm. The emission band from the dyes in the silica cores was more narrow and the intensity was enhanced with growth of silver shell thickness due to coupling of the emission light from Ru(bpy)3(2+) in the cores with the metal plasmon from the silver shells. The enhancement of emission intensity was also dependent on the size of the silica core, showing that the enhancement efficiency decreased with an increase in the size of the silica beads. Lifetime measurements support the coupling mechanism between the dye and metal shell. This study can be used to develop novel dye-labeled metal particles with bright and narrow emission bands. 相似文献
44.
Ewa Pejcz Sabina Lachowicz-Winiewska Paulina Nowicka Agata Wojciechowicz-Budzisz Radosaw Spychaj Zygmunt Gil 《Molecules (Basel, Switzerland)》2021,26(14)
Inoculation of sourdough allows the fermentation medium to be dominated by desired microorganisms, which enables determining the kinetics of the conversion of chemical compounds by individual microorganisms. This knowledge may allow the design of functional food products with health features dedicated to consumers with special needs. The aim of the study was to assess the dynamics of transformations of fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) compounds from wheat flour as well as their antioxidant activity during inoculated and spontaneous sourdough fermentation. The FODMAP content in grain products was determined by the fructan content with negligible amounts of sugars and polyols. To produce a low-FODMAP cereal product, the fermentation time is essential. The 72 h fermentation time of L. plantarum-inoculated sourdough reduced the FODMAP content by 91%. The sourdough fermentation time of at least 72 h also positively influenced the content of polyphenols and antioxidant activity, regardless of the type of fermentation. The inoculation of both L. plantarum and L. casei contributed to a similar degree to the reduction in FODMAP in sourdough compared to spontaneous fermentation. 相似文献
45.
J. Młyńczak K. Kopczyński Z. Mierczyk M. Zygmunt S. Natkański M. Muzal J. Wojtanowski P. Kirwil M. Jakubaszek P. Knysak W. Piotrowski A. Zarzycka A. Gawlikowski 《Opto-Electronics Review》2013,21(3):332-337
The paper describes practical application of pulsed microchip laser generating at 1535-nm wavelength to a laser rangefinder. The complete prototype of a laser rangefinder was built and investigated in real environmental conditions. The measured performance of the device is discussed. To build the prototype of a laser rangefinder at a reasonable price and shape a number of basic considerations had to be done. These include the mechanical and optical design of a microchip laser and the opto-mechanical construction of the rangefinder. 相似文献
46.
Fluorescence amplification by electrochemically deposited silver nanowires with fractal architecture
Goldys EM Drozdowicz-Tomsia K Xie F Shtoyko T Matveeva E Gryczynski I Gryczynski Z 《Journal of the American Chemical Society》2007,129(40):12117-12122
Electrochemically deposited silver structures with nanowires 50-100 nm in diameter show high fluorescence amplification and strongly reduced fluorescence lifetimes. Both quantities depend on the structure thickness. With increasing thickness the fluorescence amplification proportionally increases and the fluorescence lifetime decreases. This thickness dependence is caused by fluorophore interaction with a system of plasmon excitations in coupled nanowires extending over micrometer size regions. Thus the amplification is attributed to a combination of extended structure area and strong plasmonic coupling between nanowires which also help to radiatively scatter the fluorescence emission. 相似文献
47.
Investigation of adsorption and vertical migration of137Cs in three kinds of soil at Lublin vicinity
S. Chibowski J. Zygmunt Z. Klimowicz 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):287-295
The results of field, column and laboratory studies carried out on three types of mineral soils are encloses presented. Based
on the field tests, average migration rates of137Cs were calculated. The highest rate was found for the brown soil (FAO/UNESCO—Cambisol). Cesium migrated with the lowest rate
in the podzol soil (FAO/UNESCO—Cambic Podzol). The column experiments confirmed the above observation. In laboratory tests
the adsorption and desorption isotherms of Cs were determined on samples taken from 0–2 cm layers of each soil profile. It
was found from the calculated partition coefficients that Cs is always irreversibly bonded to some extent, but it appears
to be completely and irreversibly immobilized on the podzol soil. The permanent retention of cesium in the podzol soil was
also confirmed by microcalorimetric studies. The desorption energy was negligibly small and amounted to −0.21 mJ/g. In the
brown soil, containing prevailing amounts of loamy minerals, the desorption energy was found to be 106.89 mJ/g. The investigations
are supplemented by the sorption kinetics measurements. These indicate that the adsorption equilibrium is reached after a
dozen, up to twenty or so minutes. 相似文献
48.
Danuta Gorlo Bogdan Zygmunt Marta Dudek Anna Jaszek Michał Pilarczyk J. Namieśnik 《Analytical and bioanalytical chemistry》1999,363(7):696-699
Practical application of Solid-Phase Microextraction (SPME) for the assessment of the quality of indoor air is presented.
SPME was used to sample selected organic pollutants (carbon tetrachloride, benzene, toluene, chlorobenzene, p-xylene and n-decane). An SPME fiber was coated with a 100 μm film of polydimethylsiloxane. The analytes extracted were analysed with a
gas chromatograph directly coupled with a mass spectrometer (GC-MS). The method was used to assess the indoor air quality
in a few selected flats. The concentrations ranged from below detection limits to 6.9 mg/m3 for benzene depending on the flat; they were relatively high for newly built or freshly renovated flats.
Received: 14 July 1998 / Revised: 17 November 1998 / Accepted: 21 November 1998 相似文献
49.
Zygmunt Bak 《Czechoslovak Journal of Physics》1999,49(11):1525-1529
Within an analytical approach we study the RKKY interaction mediated by the electron gas, which shows fractional spectral
dimensionality. We derive formula for the RKKY exchange integral in a system of nonintegral dimensionality. Also the modifications
of magnetic interaction and magnetic moments in metallic overlayers due to the surface/interface effects are considered.
Presented at the VIII-th Symposium on Surface Physics, Třešt’ Castle, Czech Republic, June 28 – July 2, 1999. 相似文献
50.
The role of water’s H-bond percolation network in acid-assisted proton transfer was studied in water and glycerol solutions
and in sugar glasses. Proton transfer rates were determined by the fluorescence of pyrene-1-carboxylate, a compound with a
higher pK in its excited state relative to the ground state. Excitation of pyrene-1-COO− produces fluorescence from pyrene-1-COOH when a proton is accepted during the excited singlet state lifetime of pyrene-1-COO−. The presence of glycerol as an aqueous cosolvent decreases proton transfer rates from phosphoric and acetic acid in a manner
that does not follow the Stokes relationship on viscosity. In sugar glass composed of trehalose and sucrose, proton transfer
occurs when phosphate is incorporated in the glass. Sugar glass containing phosphate retains water and it is suggested that
proton transfer requires this water. The infrared (IR) frequency of water bending mode in sugar glass and in aqueous solution
is affected by the presence of phosphate and the IR spectral bands of all phosphate species in water are temperature dependent;
both results are consistent with H-bonding between water and phosphate. The fluorescence results, which studied the effect
of cosolvent, highlight the role of water in assisting proton transfer in reactions involving biological acids, and the IR
results, which give spectroscopic evidence for H-bonding between water and phosphate, are consistent with a mechanism of proton
transfer involving H-bonding. The possibility that the phosphate-rich surface of membranes assists in proton equilibration
in cells is discussed. 相似文献