Evidence for Chemical Interaction in Carbon and Polymer Associations. Butyl and Acidic Oxy Blacks. The Possible Role of Carboxylic Acid Groups on the Black

1969 ◽  
Vol 42 (3) ◽  
pp. 850-857 ◽  
Author(s):  
A. M. Gessler
Keyword(s):  
Carboxylic Acid ◽  
Chemical Interaction ◽  
Interaction Mechanism ◽  
Carboxyl Groups ◽  
Carboxylic Acid Groups

Abstract Assuming that the enhanced reinforcement capacity of oxidized black in butyl is related specifically to acidity provided by carboxyl groups on the surface of the black, the black was neutralized by esterification and saponification, respectively. The reduced carbon-polymer bonding activity resulting from these neutralizations is discussed in the light of the cationic interaction mechanism which it is proposed is involved.

Metal organic frameworks decorated with free carboxylic acid groups: topology, metal capture and dye adsorption properties

2020 ◽  
Vol 49 (41) ◽  
pp. 14690-14705
Author(s):  
M. Naqi Ahamad ◽  
M. Shahnawaz Khan ◽  
M. Shahid ◽  
Musheer Ahmad
Keyword(s):  
Carboxylic Acid ◽  
Metal Organic Frameworks ◽  
Dye Adsorption ◽  
Adsorption Properties ◽  
Carboxylic Acid Groups ◽  
Metal Capture ◽  
Metal Organic

Elaborating the role of uncoordinated carboxylic acid functions in MOFs in post synthetic modification (PSM) through metal capture and hence in tuning dye adsorption properties.

Preparation of cross-linked poly(vinyl alcohol) films from copolymers with benzoxaborole and carboxylic acid groups, and their degradability in an oxidizing environment

2020 ◽  
Vol 11 (14) ◽  
pp. 2469-2474
Author(s):  
Nao Hakuto ◽  
Katsuya Saito ◽  
Masayuki Kirihara ◽  
Yohei Kotsuchibashi
Keyword(s):  
Carboxylic Acid ◽  
Vinyl Alcohol ◽  
Carboxyl Groups ◽  
Poly Vinyl Alcohol ◽  
Carboxylic Acid Groups

Functionalized PVA films were prepared from copolymers with benzoxaborole and carboxyl groups.

Role of carboxylic acid groups in the reduction of nitric oxide by carbon at low temperature, as exemplified by graphene oxide

2017 ◽  
Vol 19 (33) ◽  
pp. 22462-22471 ◽  
Author(s):  
J. Zhang ◽  
Q. Gao ◽  
X. M. Li ◽  
J. Z. Zhou ◽  
X. X. Ruan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Graphene Oxide ◽  
Carboxylic Acid ◽  
Low Temperature ◽  
Active Sites ◽  
Reduction Of No ◽  
Carboxylic Acid Groups ◽  
Nano Carbon ◽  
First Time

This work reported the reduction of NO by carboxylic acid groups and the derived active sites on nano-carbon at a temperature as low as 100 °C for the first time.

Role of Hydrogen Bonding in the pH-Dependent Aggregation of Colloidal Gold Particles Bearing Solution-Facing Carboxylic Acid Groups

2009 ◽  
Vol 113 (32) ◽  
pp. 14236-14244 ◽  
Author(s):  
Thomas C. Preston ◽  
Mohammad Nuruzzaman ◽  
Nathan D. Jones ◽  
Silvia Mittler
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Colloidal Gold ◽  
Gold Particles ◽  
Carboxylic Acid Groups ◽  
Ph Dependent

scholarly journals Protonation of carboxyl groups in EuDOTA-tetraamide complexes results in catalytic prototropic exchange and quenching of the CEST signal

2017 ◽  
Vol 375 (2107) ◽  
pp. 20170113 ◽  
Author(s):  
Lei Zhang ◽  
Osasere M. Evbuomwan ◽  
Michael Tieu ◽  
Piyu Zhao ◽  
Andre F. Martins ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Water Molecule ◽  
Bound Water ◽  
Bulk Water ◽  
Proton Exchange ◽  
Ethyl Esters ◽  
Carboxyl Groups ◽  
Carboxylic Acid Groups ◽  
Coordination Isomers ◽  
Ph Range

The CEST properties of EuDOTA-tetraamide complexes bearing pendant carboxylate and carboxyl ethyl esters were measured as a function of pH. The CEST signal from the Eu 3+ -bound water molecule decreased in intensity between pH 8.5 and 4.5 while the proton exchange rates ( k ex ) increased over this same pH range. In comparison, the CEST signal in the corresponding carboxyl ester derivatives was nearly constant. Both observations are consistent with stepwise protonation of the four carboxylic acid groups over this same pH range. This indicates that negative charges on the carboxyl groups above pH 6 facilitate the formation of a strong hydrogen-bonding network in the coordination second sphere above the single Eu 3+ -bound water molecule, thereby decreasing prototropic exchange of protons on the bound water molecule with bulk water protons. The percentage of square antiprismatic versus twisted square antiprism coordination isomers also decreased as the appended carboxylic acid groups were positioned further away from the amide. The net effect of lowering the pH was an overall increase in k ex and a quenching of the CEST signal. This article is part of the themed issue ‘Challenges for chemistry in molecular imaging’.

scholarly journals 5,6-Dihydroxyindole-2-carboxylic acid is incorporated in mammalian melanin

1992 ◽  
Vol 286 (2) ◽  
pp. 491-495 ◽  
Author(s):  
K Tsukamoto ◽  
A Palumbo ◽  
M D'Ischia ◽  
V J Hearing ◽  
G Prota
Keyword(s):  
Carboxylic Acid ◽  
Carboxyl Groups

The role of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) in the biosynthesis of melanins has been studied by using the incorporation of specifically radiolabelled melanogenic precursors into melanins formed by melanocytes growing in vitro and in vivo. Extracts of mouse melanocytes and intact viable melanocytes were found to incorporate into melanin from 25% to more than 60% of [1-14C]tyrosine. Melanins from melanoma tumours grown in mice were radiolabelled with 3,4-dihydroxy[1-14C]phenylalanine, purified and chemoselectively decarboxylated. Determination of the 14CO2 evolved showed that at least 20% of the precursor incorporated in vivo retains the label in the form of non-aminoacidic aromatic-type carboxyl groups. These results provide the first unambiguous demonstration that DHICA is incorporated in physiologically relevant amounts in mammalian melanins.

scholarly journals The role of carboxylic acid groups in the action of glucoamylase I

FEBS Letters ◽  
1973 ◽  
Vol 29 (2) ◽  
pp. 197-200 ◽  
Author(s):  
C.J. Gray ◽  
M.E. Jolley
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acid Groups

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

scholarly journals Modulation of Macrophages M1/M2 Polarization Using Carbohydrate-Functionalized Polymeric Nanoparticles

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 88
Author(s):  
Raquel G. D. Andrade ◽  
Bruno Reis ◽  
Benjamin Costas ◽  
Sofia A. Costa Lima ◽  
Salette Reis
Keyword(s):  
Inflammatory Responses ◽  
Polymeric Nanoparticles ◽  
Interaction Mechanism ◽  
Mannose Receptor ◽  
The Body ◽  
Receptor Expression ◽  
Production Methods ◽  
Polymeric Nanocarriers ◽  
Efficient Delivery

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

scholarly journals Grafting TRAIL through Either Amino or Carboxylic Groups onto Maghemite Nanoparticles: Influence on Pro-Apoptotic Efficiency

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 502
Author(s):  
Hanene Belkahla ◽  
Andrei Alexandru Constantinescu ◽  
Tijani Gharbi ◽  
Florent Barbault ◽  
Alexandre Chevillot-Biraud ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Cancer Therapy ◽  
Computational Study ◽  
Carcinoma Cells ◽  
Maghemite Nanoparticles ◽  
Carboxylic Acid Groups ◽  
Lung Carcinoma Cells ◽  
Biological Studies ◽  
Apoptotic Effect ◽  
Carboxylic Groups

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF cytokine superfamily. TRAIL is able to induce apoptosis through engagement of its death receptors DR4 and DR5 in a wide variety of tumor cells while sparing vital normal cells. This makes it a promising agent for cancer therapy. Here, we present two different ways of covalently grafting TRAIL onto maghemite nanoparticles (NPs): (a) by using carboxylic acid groups of the protein to graft it onto maghemite NPs previously functionalized with amino groups, and (b) by using the amino functions of the protein to graft it onto NPs functionalized with carboxylic acid groups. The two resulting nanovectors, NH-TRAIL@NPs-CO and CO-TRAIL@NPs-NH, were thoroughly characterized. Biological studies performed on human breast and lung carcinoma cells (MDA-MB-231 and H1703 cell lines) established these nanovectors are potential agents for cancer therapy. The pro-apoptotic effect is somewhat greater for CO-TRAIL@NPs-NH than NH-TRAIL@NPs-CO, as evidenced by viability studies and apoptosis analysis. A computational study indicated that regardless of whether TRAIL is attached to NPs through an acid or an amino group, DR4 recognition is not affected in either case.

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