Sorption of microorganisms by wide-porous agarose cryogels containing grafted aliphatic chains of different length

The possibility of fractionation of heterogeneous bacterial populations using wide-porous agarose cryogels containing grafted aliphatic groups with the chain lengths of 4, 7, and 12 carbon atoms was demonstrated for the first time. The maximum sorption of vegetative cells of gram-positive bacteria (60%) was shown for the polymeric carrier with the chain length of 4 carbon atoms, while the hypometabolic cells appearing in the population after prolonged (60-day) cultivation were trapped by wide-porous affinity sorbents with C7- and C12- aliphatic groups much better than vegetative cells. © Pleiades Publishing, Ltd 2009

Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure

Two-Photon Fluorescence Microscopy Imaging of Cellular Oxidative Stress Using Profluorescent Nitroxides

A range of varying chromophore nitroxide free radicals and their nonradical methoxyamine analogues were synthesized and their linear photophysical properties examined. The presence of the proximate free radical masks the chromophore’s usual fluorescence emission, and these species are described as profluorescent. Two nitroxides incorporating anthracene and fluorescein chromophores (compounds 7 and 19, respectively) exhibited two-photon absorption (2PA) cross sections of approximately 400 G.M. when excited at wavelengths greater than 800 nm. Both of these profluorescent nitroxides demonstrated low cytotoxicity toward Chinese hamster ovary (CHO) cells. Imaging colocalization experiments with the commercially available CellROX Deep Red oxidative stress monitor demonstrated good cellular uptake of the nitroxide probes. Sensitivity of the nitroxide probes to H2O2-induced damage was also demonstrated by both one- and two-photon fluorescence microscopy. These profluorescent nitroxide probes are potentially powerful tools for imaging oxidative stress in biological systems, and they essentially “light up” in the presence of certain species generated from oxidative stress. The high ratio of the fluorescence quantum yield between the profluorescent nitroxide species and their nonradical adducts provides the sensitivity required for measuring a range of cellular redox environments. Furthermore, their reasonable 2PA cross sections provide for the option of using two-photon fluorescence microscopy, which circumvents commonly encountered disadvantages associated with one-photon imaging such as photobleaching and poor tissue penetration

Living Bacterial Sacrificial Porogens to Engineer Decellularized Porous Scaffolds

Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types

Sorption of microorganisms by wide-porous agarose cryogels containing grafted aliphatic chains of different length

The possibility of fractionation of heterogeneous bacterial populations using wide-porous agarose cryogels containing grafted aliphatic groups with the chain lengths of 4, 7, and 12 carbon atoms was demonstrated for the first time. The maximum sorption of vegetative cells of gram-positive bacteria (60%) was shown for the polymeric carrier with the chain length of 4 carbon atoms, while the hypometabolic cells appearing in the population after prolonged (60-day) cultivation were trapped by wide-porous affinity sorbents with C7- and C12- aliphatic groups much better than vegetative cells. © Pleiades Publishing, Ltd 2009

Sorption of microorganisms by wide-porous agarose cryogels containing grafted aliphatic chains of different length

The possibility of fractionation of heterogeneous bacterial populations using wide-porous agarose cryogels containing grafted aliphatic groups with the chain lengths of 4, 7, and 12 carbon atoms was demonstrated for the first time. The maximum sorption of vegetative cells of gram-positive bacteria (60%) was shown for the polymeric carrier with the chain length of 4 carbon atoms, while the hypometabolic cells appearing in the population after prolonged (60-day) cultivation were trapped by wide-porous affinity sorbents with C7- and C12- aliphatic groups much better than vegetative cells. © Pleiades Publishing, Ltd 2009

Sorption of microorganisms by wide-porous agarose cryogels containing grafted aliphatic chains of different length

The possibility of fractionation of heterogeneous bacterial populations using wide-porous agarose cryogels containing grafted aliphatic groups with the chain lengths of 4, 7, and 12 carbon atoms was demonstrated for the first time. The maximum sorption of vegetative cells of gram-positive bacteria (60%) was shown for the polymeric carrier with the chain length of 4 carbon atoms, while the hypometabolic cells appearing in the population after prolonged (60-day) cultivation were trapped by wide-porous affinity sorbents with C7- and C12- aliphatic groups much better than vegetative cells. © Pleiades Publishing, Ltd 2009