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Sulphonic Acid (sulphonic + acid)

Distribution by Scientific Domains

Medical Sciences	53%
Polymers and Materials Science	20%
Chemistry	20%

Selected Abstracts

Sulphonic acids doped poly(N -ethyl aniline): A material for humidity sensing application

POLYMER ENGINEERING & SCIENCE, Issue 10 2007
Milind V. Kulkarni
Substituted polyaniline, poly(N- ethyl aniline) (PNEA), doped with camphor sulphonic acid (CSA) and p -toluene sulphonic acid (p -TSA), was synthesized by single-step chemical polymerization method using ammonium persulphate as an oxidizing agent. This is a single-step polymerization process to synthesize directly the conducting emeraldine salt phase of the polymer using CSA and p -toluene sulphonic acid as dopants. The synthesized polymers were characterized by UV,vis and FTIR spectroscopy, scanning electron microscopy, TGA/SDTA, DSC, and conductivity measurements. This single-step chemical synthesis method offers a polymer having very good physicochemical properties with good electrical conductivity. High temperature conductivity measurements show "thermal activated behavior." The change in resistance with respect to % relative humidity (% RH) is observed, when pressed pellets of the polymer were exposed to the broad range of humidity (ranging between 20 and 100% RH). POLYM. ENG. SCI., 47:1621,1629, 2007. © 2007 Society of Plastics Engineers [source]

Novel synthesis of flavour quality , -lactones

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2006
Dhananjay D. Zope
Abstract The cyclization of 3-alkenoic acids with 80% sulphuric acid in the synthesis of , -lactones is always associated with fumes of sulphur dioxide gas and traces of cyclopentenones. The cyclopentenones formed during the reaction give off-odours to the , -lactones formed. Two catalysts, p -toluene sulphonic acid and o -phosphoric acid, with a catalytic amount of perchloric acid, were tried in the lactonization reaction to obtain , -lactones in high yields, and the reaction was free from sulphur dioxide gas fumes and cyclopentenones. A comparison of these catalysts with 80% sulphuric acid in the synthesis of , -lactones was also made. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Activator protein-1 signalling pathway and apoptosis are modulated by poly(ADP-ribose) polymerase-1 in experimental colitis

IMMUNOLOGY, Issue 4 2004
Basilia Zingarelli
Summary Poly(ADP-ribose) polymerase-1 (PARP-1) is activated in response to DNA injury in the nucleus of eukaryotic cells and has been implicated in intestinal barrier dysfunction during inflammatory bowel diseases. In this study we investigated whether PARP-1 may regulate the inflammatory response of experimental colitis at the level of signal transduction mechanisms. Mice genetically deficient of PARP-1 (PARP-1,/,) and wild-type littermates were subjected to rectal instillation of trinitrobenzene sulphonic acid (TNBS). Signs of inflammation were monitored for 14 days. In wild-type mice, TNBS treatment resulted in colonic ulceration and marked apoptosis, which was associated with decreased colon content of the antiapoptotic protein Bcl-2, whereas the proapoptotic Bax was unchanged. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were associated with activation of c-Jun-NH2 terminal kinase (JNK), phosphorylation of c-Jun and activation of the nuclear transcription factor activator protein-1 (AP-1) in the colon. In contrast, PARP-1,/, mice exhibited a significant reduction of colon damage and apoptosis, which was associated with increased colonic expression of Bcl-2 and lower levels of plasma nitrate/nitrite when compared to wild-type mice. Amelioration of colon damage was associated with a significant reduction of the activation of JNK and reduction of the DNA binding of AP-1. The data indicate that PARP-1 exerts a pathological role in colitis possibly by regulating the early stress-related transcriptional response through a positive modulation of the AP-1 and JNK pathways. [source]

Design, Synthesis and Evaluation of N -Basic Substituted 3-Hydroxypyridin-4-ones: Orally Active Iron Chelators with Lysosomotrophic Potential

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2000
ZU D. LIU
To investigate the possibility of targeting chelators into the lysosomal iron pool, nine bidentate 3-hydroxypyridin-4-ones with basic chains have been synthesized. As the turnover of ferritin iron is centred in the lysosome, such strategy is predicted to increase chelator efficacy of bidentate ligands. The pKa values of the ligands together with their distribution coefficients between 1-octanol and 4-morpholinepropane sulphonic acid (MOPS) buffer pH 7.4 have been determined. The in-vivo iron mobilization efficacy of these basic 3-hydroxypyridin-4-ones has been investigated in a 59Fe-ferritin-loaded rat model. No obvious correlation was observed between efficacy and the pKa value of the side chain, although those with pKa > 7.0 tended to be more efficient than those with pKa < 7.0. The imidazole-containing molecules are much less effective than the tertiary amine derivatives. A dose-response study suggested that basic pyridinones are relatively more effective at lower doses when compared with N -alkyl hydroxypyridinones. Optimal effects were observed with the piperidine derivatives 4h and 4i. The derivative 4i at a dose of 150 ,mol kg,1 was more effective than 450 ,mol kg,1 deferiprone, the widely adopted clinical dose. [source]

Sunscreens , what's important to know

JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 9 2008
C Antoniou
Abstract The popularity of sunscreens dramatically increased since ultraviolet irradiation was implicated in the pathogenesis of skin cancer and skin ageing. The absorption properties, safety, photostability of different organic and inorganic filters are reviewed: para -aminobenzoic acid, salicylates, cinnamates, benzophenones, butylmethoxydibenzoylmethane (Parsol 1789), drometrizole trisulphonic (Mexoryl XL), terephthalydene dicamphor sulphonic acid (Mexoryl SX), methylene bisbenzotriazol tetramethylbutylphenol (Tinasorb M), anisotriazine (Tinasorb S), titanium dioxide and zinc oxide. Furthermore, this review discusses the optimal methods for measuring the protection that a sunscreen offers, the role of sunscreen use in melanoma prevention and future trends in sunscreen filters development. [source]

Corticotropin-releasing hormone receptor 1 antagonist blocks colonic hypersensitivity induced by a combination of inflammation and repetitive colorectal distension

NEUROGASTROENTEROLOGY & MOTILITY, Issue 10 2008
K. Saito-nakaya
Abstract, Gastroenteritis is one of the risk factors for developing irritable bowel syndrome (IBS). However, the precise mechanism of postinfectious IBS is still unknown. We tested the hypothesis that a combination of previous inflammation and repetitive colorectal distention (CRD) makes the colon hypersensitive and that treatment with a corticotropin-releasing hormone receptor 1 (CRH-R1) antagonist blocks this colonic hypersensitivity. Rats were pretreated with vehicle or 2,4,6-trinitrobenzene sulphonic acid (TNBS) 6 weeks before CRD. For the CRD experiment, the colorectum was distended once a day for six consecutive days. The CRH-R1 antagonist (CP-154,526, 20 mg kg,1) or vehicle was injected subcutaneously 30 min before CRD. Visceral perception was quantified as visceromotor response (VMR) using an electromyograph. For histological examination, the rats were killed on the last day of CRD experiment, and haematoxylin and eosin-staining of colon segments was performed. Although from the first to the third day of CRD, VMRs increased in both the vehicle-treated rats and TNBS-treated rats, they were significantly higher in TNBS-treated rats than those in vehicle-treated controls. On the fifth day of CRD, however, VMRs in the vehicle-treated rats were significantly greater than those in TNBS-treated rats. Pretreatment of rats with CP-154,526 significantly attenuated the increase in VMR induced by repetitive CRD with previous inflammation. Finally, we found that repetitive CRD and repetitive CRD after colitis induced visceral inflammation. These results indicate that a combination of previous inflammation and repetitive CRD induces visceral hypersensitivity and that a CRH-R1 antagonist attenuates this response in rats. [source]

Neural mechanisms of early postinflammatory dysmotility in rat small intestine

NEUROGASTROENTEROLOGY & MOTILITY, Issue 12 2006
I. Demedts
Abstract, Although human postinflammatory dysmotility is known, so far animal studies have primarily investigated changes during inflammation. Here, we focused on postinflammatory changes in rat jejunal myenteric plexus and jejunal motility. Evolution of ethanol/2,4,6-tri-nitrobenzene sulphonic acid (TNBS)-induced inflammation was assessed histologically and by measuring myeloperoxidase activity (MPO). Electromyography and immunohistochemistry were performed 1 week after ethanol/TNBS and also after NG -nitro- l -arginine methyl ester (l -NAME) administration. Ethanol/TNBS induced a transient inflammation, with normalization of MPO and histological signs of an early phase of recovery after 1 week. The number of cholinergic neurones was not altered, but myenteric neuronal nitric oxide synthase (nNOS)-immunoreactivity was significantly lower in the early phase of recovery after TNBS compared with water (1.8 ± 0.2 vs 3.5 ± 0.2 neurones ganglion,1, P < 0.001). Interdigestive motility was disrupted with a loss of phase 1 quiescence, an increase of migrating myoelectric complex cycle length, a higher number of non-propagated activity fronts and a decrease of adequately propagated phase 3 s after TNBS. Administration of l -NAME resulted in a similar disruption of interdigestive motility patterns. In the early phase of recovery after ethanol/TNBS-induced jejunal inflammation, a loss of motor inhibition occurs due to a decrease of myenteric nNOS activity. These observations may provide a model for early postinflammatory dysmotility syndromes. [source]

A comparative study on camphorsulphonic acid modified montmorillonite clay based conducting polymer nanocomposites

POLYMER COMPOSITES, Issue 5 2010
Ufana Riaz
Nanotechnology has emerged as a subject of immense academic interest and excitement in the past few decades. The immediate goal of this science aims at the production of high performance nanomaterials. The present study reports comparative investigations on the in situ polymerization of polyaniline (PANI), and its derivatives poly(1-naphthylamine) (PNA) and poly(o -toluidine) (POT) within the camphor sulphonic acid (CSA) modified montmorillonite (MMT) layers. The polymerization as well as intercalation of the conducting polymers was confirmed by FT-IR, UV-visible spectroscopies, and XRD studies, whereas the morphology of the nanocomposites was analyzed by TEM studies. It was found that the PANI derivatives (PNA and POT) revealed higher intercalation as compared with PANI. The morphology of nanocomposites was found to be governed by the type of conducting polymer intercalated. A large variation in the morphology as well as particle size was observed between the nanocomposites of PANI and its derivatives. The conductivity was found to be in the range of 10,3,10,2 S·cm,1. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source]

Sulphonic acids doped poly(N -ethyl aniline): A material for humidity sensing application

Synaptic facilitation and enhanced neuronal excitability in the submucosal plexus during experimental colitis in guinea-pig

THE JOURNAL OF PHYSIOLOGY, Issue 3 2005
Alan E. Lomax
Intestinal secretion is regulated by submucosal neurones of the enteric nervous system. Inflammation of the intestines leads to aberrant secretory activity; therefore we hypothesized that the synaptic and electrical behaviours of submucosal neurones are altered during colitis. To test this hypothesis, we used intracellular microelectrode recording to compare the excitability and synaptic properties of submucosal neurones from normal and trinitrobenzene sulphonic acid (TNBS)-inflamed guinea-pig colons. Inflammation differentially affected the electrophysiological characteristics of the two functional classes of submucosal neurones. AH neurones from inflamed colons were more excitable, had shorter action potential durations and reduced afterhyperpolarizations. Stimulus-evoked fast and slow excitatory postsynaptic potentials (EPSPs) in S neurones were larger during colitis, and the incidence of spontaneous fast EPSPs was increased. In control preparations, fast EPSPs were almost completely blocked by the nicotinic receptor antagonist hexamethonium, whereas fast EPSPs in inflamed S neurones were only partially inhibited by hexamethonium. In inflamed tissues, components of the fast EPSP in S neurones were sensitive to blockade of P2X and 5-HT3 receptors while these antagonists had little effect in control preparations. Control and inflamed S neurones were equally sensitive to brief application of acetylcholine, ATP and 5-HT, suggesting that synaptic facilitation was due to a presynaptic mechanism. Immunoreactivity for 5-HT in the submucosal plexus was unchanged by inflammation; this indicates that altered synaptic transmission was not due to anatomical remodelling of submucosal nerve terminals. This is the first demonstration of alterations in synaptic pharmacology in the enteric nervous system during inflammation. [source]

Photoallergic contact dermatitis is uncommon

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2001
A. Darvay
Background Despite the enormous increase in sunscreen use, allergic contact (AC) and photoallergic (PA) reactions to ultraviolet (UV) filters are considered rare. Objectives To analyse the data from 2715 patients who underwent photopatch testing at St John's Institute of Dermatology during the period 1983,98. Methods A retrospective analysis of all positive photopatch test episodes was undertaken with the results retrieved from the environmental dermatology database and further verified with the original archived patch test documentation for each individual patient. Results In 111 patients with positive reactions (4·1%), there were 155 AC or PA reactions to allergens in the photopatch test series. Eighty PA reactions were observed in 62 (2·3%) patients (32 men and 30 women, age range 28,75 years), with UV filters accounting for 52 positive reactions (65%), drugs 16 (20%), musk ambrette 11 (14%) and the antiseptic trichlorocarbanilide one (1%). The most common UV filter photoallergen was benzophenone-3 with 14 positive results, followed by benzophenone-10 (n = 9), isopropyl dibenzoylmethane (n = 6), p -aminobenzoic acid (PABA) (n = 5), octyl dimethyl PABA (n = 5), butyl methoxydibenzoylmethane (n = 4), isoamyl methoxycinnamate (n = 2), ethyl methoxycinnamate (n = 2), octyl methoxycinnamate (n = 2), amyl dimethyl PABA (n = 2) and phenylbenzimidazole sulphonic acid (n = 1). A similar number of AC reactions to UV filters was detected in this study. Thus 49 patients (1·8%) had a total of 75 reactions: 51 due to UV filters and 24 as a result of exposure to fragrances and therapeutic agents. Benzophenone-10 accounted for 13 AC reactions and benzophenone-3 for eight reactions. Twenty-two patients had a PA reaction alone, whereas 19 patients had chronic actinic dermatitis and 15 patients polymorphic light eruption (PLE) in addition. Thus, 34 of the 62 patients (55%) had a preceding underlying photodermatosis. Conclusions These results show a low yield of positive photopatch tests. Thus, despite the large increase in the use of UV filters over the last decade, the development of PA reactions remains rare. Furthermore, most of the common UV filter photoallergens identified in this study, including PABA, amyl dimethyl PABA and benzophenone-10, are now rarely used in sunscreen manufacture, while isopropyl dibenzoylmethane was voluntarily removed from the market in 1993. Currently, benzophenone-3 is the commonest contact photoallergen still in widespread use. In contrast, the UVB filter octyl methoxycinnamate, used in a number of sunscreens, produced only two positive PA reactions in 12 years of testing. Nevertheless, although these reactions are extremely rare, patients with photodermatoses such as PLE and chronic actinic dermatitis do represent a group of patients at increased risk of developing photoallergy. Further photopatch test series should be regularly reviewed and updated, as the relevance of individual photoallergens changes over time. Currently, there is no evidence that PA reactions represent a common clinical problem. [source]

Immunoglobulin E antibodies enhance pulmonary inflammation induced by inhalation of a chemical hapten

CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2009
C. B. Mathias
Summary Background Occupational exposure to chemicals is an important cause of asthma. Recent studies indicate that IgE antibodies enhance sensitization to chemicals in the skin. Objective We investigated whether IgE might similarly promote the development of airway inflammation following inhalation of a contact sensitizer. Methods A model of chemical-induced asthma is described in which introduction of the low-molecular-weight compound, trinitrobenzene sulphonic acid (TNBS), via the respiratory tract was used for both sensitization and challenge. The role of IgE antibodies in the immune response to inhaled TNBS in this model was assessed by comparing the responses of wild-type (WT) and IgE-deficient (IgE,/,) mice on the BALB/c background. Reconstitution of circulating IgE levels by intravenous injection of IgE antibodies into IgE,/, mice before sensitization was performed to confirm the role of IgE in any differences observed between the responses of WT and IgE,/, mice. Results Intranasal challenge of TNBS-sensitized (but not sham-sensitized control mice) induced intense pulmonary inflammation. Macrophages, eosinophils and lymphocytes, including T, B, natural killer and natural killer T cells, were recruited to the airway and the animals displayed bronchial hyperresponsiveness (BHR) to methacholine. Serum levels of murine mast cell protease-1 (mMCP-1) were elevated suggesting mast cell activation. In contrast, the development of airway inflammation, recruitment of lymphocytes, induction of BHR and production of mMCP-1 were all significantly attenuated in IgE-deficient mice. Reconstitution of IgE,/, mice with IgE (of unrelated antigen specificity) before sensitization partially restored these features of asthma. Conclusion Our data indicate that IgE antibodies non-specifically enhance the development of airway inflammation induced by exposure to chemical antigens. [source]

Molecular cloning and immunoglobulin E reactivity of a natural rubber latex lecithinase homologue, the major allergenic component of Hev b 4

CLINICAL & EXPERIMENTAL ALLERGY, Issue 11 2005
E. Sunderasan
Summary Background Hev b 4 is an allergenic natural rubber latex (NRL) protein complex that is reactive in skin prick tests and in vitro immunoassays. On SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Hev b 4 is discerned predominantly at 53,55 kDa together with a 57 kDa minor component previously identified as a cyanogenic glucosidase. Of the 13 NRL allergens recognized by the International Union of Immunological Societies, the 53,55 kDa Hev b 4 major protein is the only candidate that lacks complete cDNA and protein sequence information. Objective We sought to clone the transcript encoding the Hev b 4 major protein, and characterize the native protein and its recombinant form in relation to IgE binding. Methods The 5,/3, rapid amplification of cDNA ends method was employed to obtain the complete cDNA of the Hev b 4 major protein. A recombinant form of the protein was over-expressed in Escherichia coli. The native Hev b 4 major protein was deglycosylated by trifluoromethane sulphonic acid. Western immunoblots of the native, deglycosylated and recombinant proteins were performed using both polyclonal antibodies and sera from latex-allergic patients. Results The cDNA encoding the Hev b 4 major protein was cloned. Its open reading frame matched lecithinases in the conserved domain database and contained 10 predicted glycosylation sites. Detection of glycans on the Hev b 4 lecithinase homologue confirmed it to be a glycoprotein. The deglycosylated lecithinase homologue was discerned at 40 kDa on SDS-PAGE, this being comparable to the 38.53 kDa mass predicted by its cDNA. Deglycosylation of the lecithinase homologue resulted in the loss of IgE recognition, although reactivity to polyclonal rabbit anti-Hev b 4 was retained. IgE from latex-allergic patients also failed to recognize the non-glycosylated E. coli recombinant lecithinase homologue. Conclusion The IgE epitopes of the Hev b 4 lecithinase homologue reside mainly in its carbohydrate moiety, which also account for the discrepancy between the observed molecular weight of the protein and the value calculated from its cDNA. [source]

Effect of reactive dyes upon the uptake and antibacterial action of poly(hexamethylene biguanide) on cotton.

COLORATION TECHNOLOGY, Issue 5 2004
Part 1: Effect of bis(monochlorotriazinyl) dyes
Poly(hexamethylene biguanide) (PHMB) is of interest as a bactericide for fabrics. It has affinity for cotton by reaction with the cellulosic carboxylate groups. In this study, the capacity of undyed cotton to absorb PHMB has been determined and compared with cotton dyed with anionic bis(monochlorotriazinyl) reactive dyes. When cotton is dyed with these dyes the absorption of PHMB increases, the dye providing sulphonic acid sites with which the PHMB can react. The reacted PHMB and the percentage fixation of reactive dye were determined and from this the concentration of sulphonic acid on the dyed fibre. In the case of cotton dyed with Procion Yellow H-E4R, the dye increased the absorption of PHMB to approximately 1.45 mequiv. of biguanide per sulphonic acid group. For Procion Red H-E3B and Navy H-ER the figures were 1.18 and 1.00, respectively. [source]

Ion-pair mediated transport of small model peptides in liquid phase micro extraction under acidic conditions

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2005
J. Léon E. Reubsaet
Abstract This paper discusses the behaviour of five small model peptides in a three phase (aqueous donor-organic-aqueous acceptor) liquid phase micro extraction system in relation to their physico-chemical properties (charge, hydrophobicity). It is proved that for all peptides transport over the organic phase is mediated by aliphatic sulphonic acids. Heptane-1-sulphonic acid gave the best overall recoveries. It appeared that peptides with hydrophobic properties (IPI) and a high number of positive charges (KYK) show good recoveries and are enriched in the acceptor phase. Variation in the pH (1.6,4.4) of the donor phase shows that there are peptide-dependent optimal pH-values for their recovery. Increasing pH in the acceptor phase shows that in most cases the recovery decreases due to decreased ion-pair mediated membrane transport. For KYK the partition between the organic phase and the aqueous acceptor-phase is also driven by the solubility in the aqueous acceptor phase. Increase of the ion strength of the acceptor phase did not affect the recovery of the peptides. Except for KYK, which showed decreased recovery when the ion strength increased. Another finding is that delocalisation of positive charge causes bad recovery, probably due to incomplete ion-pair-peptide complex formation. [source]