The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Giulio Bertoloni - One of the best experts on this subject based on the ideXlab platform.
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role of ground and excited singlet state Oxygen in the red light induced stimulation of escherichia coli cell growth
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Polo, Francesca Presti, Andreas Schindl, Liesbeth Schindl, Giulio Jori, Giulio BertoloniAbstract:Irradiation of selected Escherichia coli defective strains with red-light induces a stimulation of the cell growth rate. Such effect is wavelength-dependent and is accompanied by a transient increase of the cell volume and some enzymic activities. The presence of Oxygen appears to be essential for the occurrence of a significant photostimulatory effect. The results obtained upon irradiation in the presence of quenchers (tryptophan, histidine, azide) or enhancers (deuterium oxide) of singlet Oxygen (1O2) strongly suggest that this activated Oxygen Derivative is generated by excitation of endocellular chromophores (possibly cytochromes). The reaction of 1O2 with nearby cellular targets could induce a sublethal cell damage which in turn promotes an accelerated cell metabolism.
Laura Polo - One of the best experts on this subject based on the ideXlab platform.
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role of ground and excited singlet state Oxygen in the red light induced stimulation of escherichia coli cell growth
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Polo, Francesca Presti, Andreas Schindl, Liesbeth Schindl, Giulio Jori, Giulio BertoloniAbstract:Irradiation of selected Escherichia coli defective strains with red-light induces a stimulation of the cell growth rate. Such effect is wavelength-dependent and is accompanied by a transient increase of the cell volume and some enzymic activities. The presence of Oxygen appears to be essential for the occurrence of a significant photostimulatory effect. The results obtained upon irradiation in the presence of quenchers (tryptophan, histidine, azide) or enhancers (deuterium oxide) of singlet Oxygen (1O2) strongly suggest that this activated Oxygen Derivative is generated by excitation of endocellular chromophores (possibly cytochromes). The reaction of 1O2 with nearby cellular targets could induce a sublethal cell damage which in turn promotes an accelerated cell metabolism.
Yi Rong - One of the best experts on this subject based on the ideXlab platform.
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Main Group and Transition Metal Complexes Supported by Multidentate Tripodal Ligands that Feature Nitrogen, Oxygen and Sulfur Donors: Synthesis, Structural Characterization and Appliations
'Columbia University Libraries Information Services', 2013Co-Authors: Yi RongAbstract:Chapter 1 focuses on the computational study of Zr(CH2Ph)4 and chapter 2 discusses synthesis, characterization and density functional study of 2-imidazolethione. Chapters 3 - 6 describe the synthesis, structural characterization several multidentate tripodal ligands, namely tris(mercaptoimidazolyl)-hydroborato ligand, [TmR], tris(2-pyridylseleno)methyl ligand, [Tpsem], bis(2-pyridonyl)(pyridine-2-yloxy)methyl ligand, [O-poBpom] and allyl-tris(3-t-butylpyrazolyl)borato ligand, [allylTpBut], and their application to main group and transition metals. Chapter 1 describes the analysis of a monoclinic modification of Zr(CH2Ph)4 by single crystal X-ray diffraction, which reveals that the Zr-CH2-Ph bond angles in this compound span a range of 25.1°; that is much larger than previously observed for the orthorhombic form (12.1°;). In accord with this large range, density functional theory calculations demonstrate that little energy is required to perturb the Zr-CH2-Ph bond angles in this compound. Furthermore, density functional theory calculations on Me3ZrCH2Ph indicate that bending of the Zr-CH2-Ph moiety in the monobenzyl compound is also facile, thereby demonstrating that a benzyl ligand attached to zirconium is intrinsically flexible, such that its bending does not require a buffering effect involving another benzyl ligand. Chapter 2 describes the structure of 1-t-butyl-1,3-dihydro-2H-benzimidazole-2-thione which has been determined by X-ray diffraction. The compound exists in the chalcogenone form instead of chalcogenol form, which is similar to its oxo and selone counterparts. Comparison of 2-imidazolone, 2-imidazolethione and 2-imidazoleselone compounds shows that two N-C-E bond angles in the chalcogenone forms are not symmetric. This trend can be reproduced by density functional theory calculations. Additionally, H(mbenzimBut) has intermolecular hydrogen bonding interactions, whereas its selenium counterpart does not. The C-E bond lengths of 2-imidazolone, 2-imidazolethione and 2-imidazoleselone compounds are intermediate between those of formal C-E single and double bonds, which is in accord with the notion that zwitterionic structures that feature single C+-E- dative covalent bonds provide an important contribution in such molecules. Furthermore, NBO analysis of the bonding in H(ximBut) Derivatives demonstrates that the doubly bonded C=E resonance structure is most significant for the Oxygen Derivative, whereas singly bonded C+-E- resonance structures dominate for the tellurium Derivative. This result appears to be counterintuitive, based on the fact that it opposes the trend that one would expect on the basis of electronegativity difference, however, studies on XC(E)NH2 Derivatives provide solid support for it. In this regard, the C~E bonding in these compounds is significantly different to that in chalcogenoformaldehyde Derivatives for which the bonding is well represented by a H2C=E double bonded resonance structure. Chapter 3 describes the computational study on [TmMeBenz] anion and the synthesis and characterization of [TmButBenz]Na, [TmButBenz]Tl and [TmButBenz]Tl. It is worth noting that the two thallium compounds are the first structurally characterized monovalent monomeric [TmR]Tl complexes. Chapter 4 describes the synthesis and characterization of a few [TmR]M (M = Ti, Zr, Hf) complexes, including (i) Cp[TmBut]TiCl2 and Cp[TmBut]ZrCl2, which are analogues of Cp2TiCl2 and Cp2ZrCl2; (ii) [TmBut]Zr(CH2Ph)3 and (iii) [TmBut]Hf(CH2Ph)3 and [TmAd]Hf(CH2Ph)3, which are the first structurally characterized [TmR]Hf complexes. Chapter 5 describes two multidentate, L3X type ligands, which feature [CN3] and [CNO2] donors, namely tris(2 pyridylseleno)methane, [Tpsem]H, and bis(2-pyridonyl)(pyridin-2-yloxy)methane, [O-poBpom]H. They have been synthesized, characterized, and employed in the synthesis of zinc and cadmium complexes. Chapter 6 describes the synthesis and structural characterization of a new [Tp] ligand featuring an allyl substituent on the central boron atom, namely [allylTpBut]Li is reported. The compound reacts steadily with CH3CH2SH under 350 nm UV light via a thiol-ene click reaction. The resulting [CH3CH2S(CH2)3TpBut]Li complex can further react with metal halide. For example, the reaction of [CH3CH2S(CH2)3TpBut]Li with ZnI2 produced [CH3CH2S(CH2)3TpBut]ZnI at room temperature. This study provides a simple model on the immobilization of [Tp] metal complexes to the polymer chains with -SH terminals
Francesca Presti - One of the best experts on this subject based on the ideXlab platform.
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role of ground and excited singlet state Oxygen in the red light induced stimulation of escherichia coli cell growth
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Polo, Francesca Presti, Andreas Schindl, Liesbeth Schindl, Giulio Jori, Giulio BertoloniAbstract:Irradiation of selected Escherichia coli defective strains with red-light induces a stimulation of the cell growth rate. Such effect is wavelength-dependent and is accompanied by a transient increase of the cell volume and some enzymic activities. The presence of Oxygen appears to be essential for the occurrence of a significant photostimulatory effect. The results obtained upon irradiation in the presence of quenchers (tryptophan, histidine, azide) or enhancers (deuterium oxide) of singlet Oxygen (1O2) strongly suggest that this activated Oxygen Derivative is generated by excitation of endocellular chromophores (possibly cytochromes). The reaction of 1O2 with nearby cellular targets could induce a sublethal cell damage which in turn promotes an accelerated cell metabolism.
Andreas Schindl - One of the best experts on this subject based on the ideXlab platform.
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role of ground and excited singlet state Oxygen in the red light induced stimulation of escherichia coli cell growth
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Polo, Francesca Presti, Andreas Schindl, Liesbeth Schindl, Giulio Jori, Giulio BertoloniAbstract:Irradiation of selected Escherichia coli defective strains with red-light induces a stimulation of the cell growth rate. Such effect is wavelength-dependent and is accompanied by a transient increase of the cell volume and some enzymic activities. The presence of Oxygen appears to be essential for the occurrence of a significant photostimulatory effect. The results obtained upon irradiation in the presence of quenchers (tryptophan, histidine, azide) or enhancers (deuterium oxide) of singlet Oxygen (1O2) strongly suggest that this activated Oxygen Derivative is generated by excitation of endocellular chromophores (possibly cytochromes). The reaction of 1O2 with nearby cellular targets could induce a sublethal cell damage which in turn promotes an accelerated cell metabolism.
