The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Stacey F. Bent - One of the best experts on this subject based on the ideXlab platform.
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Reaction of Phenyl Isocyanate and Phenyl Isothiocyanate with the Ge(100)-2 × 1 Surface
Journal of Physical Chemistry C, 2010Co-Authors: Paul W. Loscutoff, Keith T. Wong, Stacey F. BentAbstract:The adsorption of Phenyl isocyanate and Phenyl Isothiocyanate at the Ge(100)-2 × 1 surface was probed using multiple internal reflection Fourier transform infrared (FTIR) spectroscopy, density functional theory (DFT), and X-ray photoelectron spectroscopy (XPS). Results for Phenyl isocyanate indicate that the saturation product is a [2 + 2] cycloaddition reaction product across the C═N bond, forming a surface-bound carbonyl. DFT reveals that this is the most stable of the expected products, and its calculated vibrational spectrum agrees closely with experimental spectra. FTIR spectroscopy studies of Phenyl Isothiocyanate reveal multiple surface adducts, with the product of the [2 + 2] cycloaddition reaction across the C═S bond as the major species and the product of the [2 + 2] cycloaddition reaction across the C═N bond as a minor product. In addition to these products, an excess of sulfur measured by XPS indicates the presence of a dissociative desorption product. The DFT calculated pathways and vibration...
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reaction of Phenyl isocyanate and Phenyl Isothiocyanate with the ge 100 2 1 surface
Journal of Physical Chemistry C, 2010Co-Authors: Paul W. Loscutoff, Keith T. Wong, Stacey F. BentAbstract:The adsorption of Phenyl isocyanate and Phenyl Isothiocyanate at the Ge(100)-2 × 1 surface was probed using multiple internal reflection Fourier transform infrared (FTIR) spectroscopy, density functional theory (DFT), and X-ray photoelectron spectroscopy (XPS). Results for Phenyl isocyanate indicate that the saturation product is a [2 + 2] cycloaddition reaction product across the C═N bond, forming a surface-bound carbonyl. DFT reveals that this is the most stable of the expected products, and its calculated vibrational spectrum agrees closely with experimental spectra. FTIR spectroscopy studies of Phenyl Isothiocyanate reveal multiple surface adducts, with the product of the [2 + 2] cycloaddition reaction across the C═S bond as the major species and the product of the [2 + 2] cycloaddition reaction across the C═N bond as a minor product. In addition to these products, an excess of sulfur measured by XPS indicates the presence of a dissociative desorption product. The DFT calculated pathways and vibration...
Wolfgang E. S. Unger - One of the best experts on this subject based on the ideXlab platform.
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determination of accessible amino groups on surfaces by chemical derivatization with 3 5 bis trifluoromethyl Phenyl Isothiocyanate and xps nexafs analysis
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Nora Graf, Andreas Lippitz, Thomas Gross, Falko Pippig, Andreas Holländer, Wolfgang E. S. UngerAbstract:The determination of amino groups on surfaces capable of binding biomolecules is important for the understanding and optimization of technologically relevant coupling processes. In this study, three different types of amino-functionalized model surfaces, amino thiolate on Au, amino siloxane on Si, and polyethylene (PE) foils and films reacted with 1,2-diaminoethane (DAE) were derivatized with 3,5-bis(trifluoromethyl)Phenyl Isothiocyanate. Subsequently, these samples were analyzed by chemical derivatization X-ray photoelectron spectroscopy (CD-XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The determination of amino groups by this analytical approach allows gaining insight into the availability of groups on surfaces that can actually serve as attachment sites for biomolecules in technical applications. In the case of the amino thiolate on Au, almost 90% of the expected amino groups were detected by CD-XPS. Investigation of the amino siloxane films revealed lower yields for the derivatization reaction in the order of 30%. The lowered reaction yields are thought to be due to interactions between the amino siloxane’s amino and silanol groups or the underlying substrate, making them inaccessible to the derivatization agent. The aminated PE samples are characterized by a complex surface chemistry and structure, and reaction yields of the derivatization reaction cannot be unequivocally derived. However, 1–3% of the total carbon atoms in the surface layer were found to be bound to amino groups accessible to the derivatization agent. It can be concluded that, depending on the detailed character of the investigated amino-terminated surface, the amount of amino groups accessible to CD-XPS can be substantially lower than the total amount of amino groups present at the surface.
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Determination of accessible amino groups on surfaces by chemical derivatization with 3,5-bis(trifluoromethyl)Phenyl Isothiocyanate and XPS/NEXAFS analysis
Analytical and Bioanalytical Chemistry, 2009Co-Authors: Nora Graf, Andreas Lippitz, Thomas Gross, Falko Pippig, Andreas Holländer, Wolfgang E. S. UngerAbstract:The determination of amino groups on surfaces capable of binding biomolecules is important for the understanding and optimization of technologically relevant coupling processes. In this study, three different types of amino-functionalized model surfaces, amino thiolate on Au, amino siloxane on Si, and polyethylene (PE) foils and films reacted with 1,2-diaminoethane (DAE) were derivatized with 3,5-bis(trifluoromethyl)Phenyl Isothiocyanate. Subsequently, these samples were analyzed by chemical derivatization X-ray photoelectron spectroscopy (CD-XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The determination of amino groups by this analytical approach allows gaining insight into the availability of groups on surfaces that can actually serve as attachment sites for biomolecules in technical applications. In the case of the amino thiolate on Au, almost 90% of the expected amino groups were detected by CD-XPS. Investigation of the amino siloxane films revealed lower yields for the derivatization reaction in the order of 30%. The lowered reaction yields are thought to be due to interactions between the amino siloxane’s amino and silanol groups or the underlying substrate, making them inaccessible to the derivatization agent. The aminated PE samples are characterized by a complex surface chemistry and structure, and reaction yields of the derivatization reaction cannot be unequivocally derived. However, 1–3% of the total carbon atoms in the surface layer were found to be bound to amino groups accessible to the derivatization agent. It can be concluded that, depending on the detailed character of the investigated amino-terminated surface, the amount of amino groups accessible to CD-XPS can be substantially lower than the total amount of amino groups present at the surface.
Alice Marino - One of the best experts on this subject based on the ideXlab platform.
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The novel H2S donor 4‐carboxy‐Phenyl Isothiocyanate inhibits mast cell degranulation and renin release by decreasing intracellular calcium
British Journal of Pharmacology, 2016Co-Authors: Alice Marino, Alma Martelli, Valentina Citi, Ming Fu, Rui Wang, Vincenzo Calderone, Roberto LeviAbstract:Background and Purpose Hydrogen sulfide (H2S) modulates many pathophysiological processes, including inflammation and allergic reactions, in which mast cells act as major effector cells. IgE receptor (FceRI) cross-linking leads to an increase in intracellular calcium ([Ca+2]i), a critical step in mast cell degranulation. The aim of this study was to investigate the role of H2S in [Ca+2]i-dependent mast cell activation. Experimental Approach We investigated the effects of H2S, either endogenously produced or released by the slow H2S donor 4-carboxy-Phenyl Isothiocyanate (PhNCS-COOH), on antigenic- and non-antigenic degranulation of native murine mast cells (BMMC), human (HMC-1) and rat (RBL-2H3) mast cell lines. We measured the release of specific mast cell degranulation markers (β-hexosaminidase and renin), as well as changes in [Ca+2]i and phosphorylation of proteins downstream of FceRI activation. Key Results Endogenously produced H2S inhibited antigen-induced degranulation in RBL-2H3. Similarly, H2S released by PhNCS-COOH (10-300 μM) reduced, in a concentration-dependent manner, antigenic and non-antigenic degranulation and renin release in all mast cell types. Notably, PhNCS-COOH also prevented in a concentration-dependent mode the increase in [Ca+2]i elicited by Ca+2 ionophore, thapsigargin and FceRI activation. Moreover, PhNCS-COOH attenuated the phosphorylation of Syk, cPLA-2 and PLCγ1 in antigen-stimulated RBL-2H3 cells. Conclusion and Implications Collectively, our results demonstrate that, by attenuating the phosphorylation of proteins downstream of FceRI cross-linking on mast cells, H2S diminishes [Ca+2]i availability and thus, mast cell degranulation and renin release. These findings suggest that PhNCS-COOH could be a strategic therapeutic tool in mast cell-mediated allergic conditions. This article is protected by copyright. All rights reserved.
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the novel h2s donor 4 carboxy Phenyl Isothiocyanate inhibits mast cell degranulation and renin release by decreasing intracellular calcium
British Journal of Pharmacology, 2016Co-Authors: Alice Marino, Alma Martelli, Valentina Citi, Ming Fu, Rui Wang, Vincenzo Calderone, Roberto LeviAbstract:Background and Purpose Hydrogen sulfide (H2S) modulates many pathophysiological processes, including inflammation and allergic reactions, in which mast cells act as major effector cells. IgE receptor (FceRI) cross-linking leads to an increase in intracellular calcium ([Ca+2]i), a critical step in mast cell degranulation. The aim of this study was to investigate the role of H2S in [Ca+2]i-dependent mast cell activation. Experimental Approach We investigated the effects of H2S, either endogenously produced or released by the slow H2S donor 4-carboxy-Phenyl Isothiocyanate (PhNCS-COOH), on antigenic- and non-antigenic degranulation of native murine mast cells (BMMC), human (HMC-1) and rat (RBL-2H3) mast cell lines. We measured the release of specific mast cell degranulation markers (β-hexosaminidase and renin), as well as changes in [Ca+2]i and phosphorylation of proteins downstream of FceRI activation. Key Results Endogenously produced H2S inhibited antigen-induced degranulation in RBL-2H3. Similarly, H2S released by PhNCS-COOH (10-300 μM) reduced, in a concentration-dependent manner, antigenic and non-antigenic degranulation and renin release in all mast cell types. Notably, PhNCS-COOH also prevented in a concentration-dependent mode the increase in [Ca+2]i elicited by Ca+2 ionophore, thapsigargin and FceRI activation. Moreover, PhNCS-COOH attenuated the phosphorylation of Syk, cPLA-2 and PLCγ1 in antigen-stimulated RBL-2H3 cells. Conclusion and Implications Collectively, our results demonstrate that, by attenuating the phosphorylation of proteins downstream of FceRI cross-linking on mast cells, H2S diminishes [Ca+2]i availability and thus, mast cell degranulation and renin release. These findings suggest that PhNCS-COOH could be a strategic therapeutic tool in mast cell-mediated allergic conditions. This article is protected by copyright. All rights reserved.
Mahmoud A Abdelrahman - One of the best experts on this subject based on the ideXlab platform.
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addition reaction of Phenyl isocyanate and Phenyl Isothiocyanate to partially cyclic 1 3 diaza 1 3 butadienes synthesis of annulated 1 3 5 triazine 2 4 1h 3h diones and 2 4 1h 3h dithiones
Bulletin of the Chemical Society of Japan, 1993Co-Authors: Mahmoud A AbdelrahmanAbstract:Annulated 1,3,5-triazine-2,4(1H,3H)-diones and -2,4(1H,3H)-dithiones (8 and 9) are synthesized by a 4π+2π cyclodimerization of heterocyclic heterocumulenes (6 and 7). These heterocumulenes are generated from partially cyclic 1,3-diaza-1,3-butadienes (1a—c) by means of a 2π+2π cycloaddition reaction with Phenyl isocyanate or Phenyl Isothiocyanate and followed by dissociation of the resulting cycloadducts (1,3-diazetidinones (3) and 1,3-diazetidithiones (4)).
Roberto Levi - One of the best experts on this subject based on the ideXlab platform.
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The novel H2S donor 4‐carboxy‐Phenyl Isothiocyanate inhibits mast cell degranulation and renin release by decreasing intracellular calcium
British Journal of Pharmacology, 2016Co-Authors: Alice Marino, Alma Martelli, Valentina Citi, Ming Fu, Rui Wang, Vincenzo Calderone, Roberto LeviAbstract:Background and Purpose Hydrogen sulfide (H2S) modulates many pathophysiological processes, including inflammation and allergic reactions, in which mast cells act as major effector cells. IgE receptor (FceRI) cross-linking leads to an increase in intracellular calcium ([Ca+2]i), a critical step in mast cell degranulation. The aim of this study was to investigate the role of H2S in [Ca+2]i-dependent mast cell activation. Experimental Approach We investigated the effects of H2S, either endogenously produced or released by the slow H2S donor 4-carboxy-Phenyl Isothiocyanate (PhNCS-COOH), on antigenic- and non-antigenic degranulation of native murine mast cells (BMMC), human (HMC-1) and rat (RBL-2H3) mast cell lines. We measured the release of specific mast cell degranulation markers (β-hexosaminidase and renin), as well as changes in [Ca+2]i and phosphorylation of proteins downstream of FceRI activation. Key Results Endogenously produced H2S inhibited antigen-induced degranulation in RBL-2H3. Similarly, H2S released by PhNCS-COOH (10-300 μM) reduced, in a concentration-dependent manner, antigenic and non-antigenic degranulation and renin release in all mast cell types. Notably, PhNCS-COOH also prevented in a concentration-dependent mode the increase in [Ca+2]i elicited by Ca+2 ionophore, thapsigargin and FceRI activation. Moreover, PhNCS-COOH attenuated the phosphorylation of Syk, cPLA-2 and PLCγ1 in antigen-stimulated RBL-2H3 cells. Conclusion and Implications Collectively, our results demonstrate that, by attenuating the phosphorylation of proteins downstream of FceRI cross-linking on mast cells, H2S diminishes [Ca+2]i availability and thus, mast cell degranulation and renin release. These findings suggest that PhNCS-COOH could be a strategic therapeutic tool in mast cell-mediated allergic conditions. This article is protected by copyright. All rights reserved.
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the novel h2s donor 4 carboxy Phenyl Isothiocyanate inhibits mast cell degranulation and renin release by decreasing intracellular calcium
British Journal of Pharmacology, 2016Co-Authors: Alice Marino, Alma Martelli, Valentina Citi, Ming Fu, Rui Wang, Vincenzo Calderone, Roberto LeviAbstract:Background and Purpose Hydrogen sulfide (H2S) modulates many pathophysiological processes, including inflammation and allergic reactions, in which mast cells act as major effector cells. IgE receptor (FceRI) cross-linking leads to an increase in intracellular calcium ([Ca+2]i), a critical step in mast cell degranulation. The aim of this study was to investigate the role of H2S in [Ca+2]i-dependent mast cell activation. Experimental Approach We investigated the effects of H2S, either endogenously produced or released by the slow H2S donor 4-carboxy-Phenyl Isothiocyanate (PhNCS-COOH), on antigenic- and non-antigenic degranulation of native murine mast cells (BMMC), human (HMC-1) and rat (RBL-2H3) mast cell lines. We measured the release of specific mast cell degranulation markers (β-hexosaminidase and renin), as well as changes in [Ca+2]i and phosphorylation of proteins downstream of FceRI activation. Key Results Endogenously produced H2S inhibited antigen-induced degranulation in RBL-2H3. Similarly, H2S released by PhNCS-COOH (10-300 μM) reduced, in a concentration-dependent manner, antigenic and non-antigenic degranulation and renin release in all mast cell types. Notably, PhNCS-COOH also prevented in a concentration-dependent mode the increase in [Ca+2]i elicited by Ca+2 ionophore, thapsigargin and FceRI activation. Moreover, PhNCS-COOH attenuated the phosphorylation of Syk, cPLA-2 and PLCγ1 in antigen-stimulated RBL-2H3 cells. Conclusion and Implications Collectively, our results demonstrate that, by attenuating the phosphorylation of proteins downstream of FceRI cross-linking on mast cells, H2S diminishes [Ca+2]i availability and thus, mast cell degranulation and renin release. These findings suggest that PhNCS-COOH could be a strategic therapeutic tool in mast cell-mediated allergic conditions. This article is protected by copyright. All rights reserved.