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Sample records for enhanced mucosal reactions

  1. Enhanced mucosal reactions in AIDS patients receiving oropharyngeal irradiation

    SciTech Connect

    Watkins, E.B.; Findlay, P.; Gelmann, E.; Lane, H.C.; Zabell, A.

    1987-09-01

    The oropharynx and hypopharynx are common sites of involvement in AIDS patients with mucocutaneous Kaposi's sarcoma. The radiotherapist is often asked to intervene with these patients due to problems with pain, difficulty in swallowing, or impending airway obstruction. We have noted an unexpected decrease in normal tissue tolerance of the oropharyngeal mucosa to irradiation in AIDS patients treated in our department. Data on 12 patients with AIDS and Kaposi's sarcoma receiving oropharyngeal irradiation are presented here. Doses ranged from 1000 cGy to 1800 cGy delivered in 150-300 cGy fractions. Seven of eight patients receiving doses of 1200 cGy or more developed some degree of mucositis, four of these developed mucositis severe enough to require termination of treatment. All patients in this study received some form of systemic therapy during the course of their disease, but no influence on mucosal response to irradiation was noted. Four patients received total body skin electron treatments, but no effect on degree of mucositis was seen. Presence or absence of oral candidiasis was not an obvious factor in the radiation response of the oral mucosa in these patients. T4 counts were done on 9 of the 12 patients. Although the timing of the T4 counts was quite variable, no correlation with immune status and degree of mucositis was found. The degree of mucositis seen in these patients occurred at doses much lower than expected based on normal tissue tolerances seen in other patient populations receiving head and neck irradiations. We believe that the ability of the oral mucosa to repair radiation damage is somehow altered in patients with AIDS.

  2. Enhancement of gastric mucosal blood flow with sulglycotide.

    PubMed

    Guslandi, M; Sorghi, M; Tittobello, A

    1994-01-01

    Twelve patients with dyspepsia whose gastric abnormalities ranged from diffuse reddening of the mucosa to multiple erosions were treated for 4 weeks with oral sulglycotide, a sulphated glycopeptide with known gastroprotective and ulcer-healing properties. Before and after treatment, gastric mucosal blood flow was assessed by means of laser Doppler flowmetry. A significant (P < 0.01) increase in mucosal perfusion was observed after sulglycotide treatment, suggesting that enhancement of mucosal blood flow may contribute to the therapeutic properties of the drug.

  3. Cinnamon-induced Oral Mucosal Contact Reaction

    PubMed Central

    Vivas, Ana P. M; Migliari, Dante A

    2015-01-01

    Contact stomatitis associated with consumption of cinnamon flavoring agents is a relatively uncommon disorder. Of relevance, both clinical features and the histopathologic findings of this condition are nonspecific, and, more importantly, may resemble some other inflammatory oral mucosa disorders, eventually making diagnosis difficult. Usually a patient exhibits a combination of white and erythematous patches of abrupt onset, accompanied by a burning sensation. To shed some light on this subject, a case of a 64-year-old woman with hypersensitivity contact reaction on the oral mucosa due to cinnamon mints is presented, with emphasis on differential diagnosis and the process for confirmation of the diagnosis. The treatment consists of discontinuing the use of cinnamon products. Clinicians will be able to recognize this disorder following a careful clinical examination and detailed history. This recognition is important in order to avoid invasive and expensive diagnostic procedures. PMID:26312097

  4. Polymeric penetration enhancers promote humoral immune responses to mucosal vaccines.

    PubMed

    Klein, Katja; Mann, Jamie F S; Rogers, Paul; Shattock, Robin J

    2014-06-10

    Protective mucosal immune responses are thought best induced by trans-mucosal vaccination, providing greater potential to generate potent local immune responses than conventional parenteral vaccination. However, poor trans-mucosal permeability of large macromolecular antigens limits bioavailability to local inductive immune cells. This study explores the utility of polymeric penetration enhancers to promote trans-mucosal bioavailability of insulin, as a biomarker of mucosal absorption, and two vaccine candidates: recombinant HIV-1 envelope glycoprotein (CN54gp140) and tetanus toxoid (TT). Responses to vaccinating antigens were assessed by measurement of serum and the vaginal humoral responses. Polyethyleneimine (PEI), Dimethyl-β-cyclodextrin (DM-β-CD) and Chitosan enhanced the bioavailability of insulin following intranasal (IN), sublingual (SL), intravaginal (I.Vag) and intrarectal (IR) administration. The same penetration enhancers also increased antigen-specific IgG and IgA antibody responses to the model vaccine antigens in serum and vaginal secretions following IN and SL application. Co-delivery of both antigens with PEI or Chitosan showed the highest increase in systemic IgG and IgA responses following IN or SL administration. However the highest IgA titres in vaginal secretions were achieved after IN immunisations with PEI and Chitosan. None of the penetration enhancers were able to increase antibody responses to gp140 after I.Vag immunisations, while in contrast PEI and Chitosan were able to induce TT-specific systemic IgG levels following I.Vag administration. In summary, we present supporting data that suggest appropriate co-formulation of vaccine antigens with excipients known to influence mucosal barrier functions can increase the bioavailability of mucosally applied antigens promoting the induction of mucosal and systemic antibody responses. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Sacral nerve stimulation enhances early intestinal mucosal repair following mucosal injury in a pig model

    PubMed Central

    Brégeon, Jérémy; Coron, Emmanuel; Da Silva, Anna Christina Cordeiro; Jaulin, Julie; Aubert, Philippe; Chevalier, Julien; Vergnolle, Nathalie; Meurette, Guillaume

    2016-01-01

    Key points Reducing intestinal epithelial barrier (IEB) dysfunctions is recognized as being of major therapeutic interest for various intestinal disorders.Sacral nerve stimulation (SNS) is known to reduce IEB permeability.Here, we report in a pig model that SNS enhances morphological and functional recovery of IEB following mucosal injury induced via 2,4,6‐trinitrobenzenesulfonic acid. These effects are associated with an increased expression of tight junction proteins such as ZO‐1 and FAK.These results establish that SNS enhances intestinal barrier repair in acute mucosal injury. They further set the scientific basis for future use of SNS as a complementary or alternative therapeutic option for the treatment of gut disorders with IEB dysfunctions such as inflammatory bowel diseases or irritable bowel syndrome. Abstract Intestinal epithelial barrier (IEB) dysfunctions, such as increased permeability or altered healing, are central to intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability, but its ability to modulate IEB repair remains unknown. This study aimed to characterize the impact of SNS on mucosal repair following 2,4,6‐trinitrobenzenesulfonic acid (TNBS)‐induced lesions. Six pigs were stimulated by SNS 3 h prior to and 3 h after TNBS enema, while sham animals (n = 8) were not stimulated. The impact of SNS on mucosal changes was evaluated by combining in vivo imaging, histological and functional methods. Biochemical and transcriptomic approaches were used to analyse the IEB and mucosal inflammatory response. We observed that SNS enhanced the recovery from TNBS‐induced increase in transcellular permeability. At 24 h, TNBS‐induced alterations of mucosal morphology were significantly less in SNS compared with sham animals. SNS reduced TNBS‐induced changes in ZO‐1 expression and its epithelial pericellular distribution, and also increased pFAK/FAK expression compared with sham. Interestingly, SNS increased

  6. Sacral nerve stimulation enhances early intestinal mucosal repair following mucosal injury in a pig model.

    PubMed

    Brégeon, Jérémy; Coron, Emmanuel; Da Silva, Anna Christina Cordeiro; Jaulin, Julie; Aubert, Philippe; Chevalier, Julien; Vergnolle, Nathalie; Meurette, Guillaume; Neunlist, Michel

    2016-08-01

    Reducing intestinal epithelial barrier (IEB) dysfunctions is recognized as being of major therapeutic interest for various intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability. Here, we report in a pig model that SNS enhances morphological and functional recovery of IEB following mucosal injury induced via 2,4,6-trinitrobenzenesulfonic acid. These effects are associated with an increased expression of tight junction proteins such as ZO-1 and FAK. These results establish that SNS enhances intestinal barrier repair in acute mucosal injury. They further set the scientific basis for future use of SNS as a complementary or alternative therapeutic option for the treatment of gut disorders with IEB dysfunctions such as inflammatory bowel diseases or irritable bowel syndrome. Intestinal epithelial barrier (IEB) dysfunctions, such as increased permeability or altered healing, are central to intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability, but its ability to modulate IEB repair remains unknown. This study aimed to characterize the impact of SNS on mucosal repair following 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced lesions. Six pigs were stimulated by SNS 3 h prior to and 3 h after TNBS enema, while sham animals (n = 8) were not stimulated. The impact of SNS on mucosal changes was evaluated by combining in vivo imaging, histological and functional methods. Biochemical and transcriptomic approaches were used to analyse the IEB and mucosal inflammatory response. We observed that SNS enhanced the recovery from TNBS-induced increase in transcellular permeability. At 24 h, TNBS-induced alterations of mucosal morphology were significantly less in SNS compared with sham animals. SNS reduced TNBS-induced changes in ZO-1 expression and its epithelial pericellular distribution, and also increased pFAK/FAK expression compared with sham. Interestingly, SNS increased the mucosal density of neutrophils

  7. Enhancing the buccal mucosal uptake and retention of triamcinolone acetonide.

    PubMed

    Nicolazzo, Joseph A; Reed, Barry L; Finnin, Barrie C

    2005-07-20

    In this study, the buccal mucosal uptake and retention of triamcinolone acetonide (TAC) were assessed in the presence of the skin penetration enhancer, Azone (AZ). Porcine buccal mucosa was excised, mounted in modified Ussing chambers, and pretreated with ethanolic solutions of AZ. After 2 h, the rate of TAC disappearance from the donor chamber and TAC appearance in the receptor chamber was monitored, and the mucosal retention of TAC was determined at the completion of the experiment. The permeability and mucosal uptake of TAC was also determined using the TAC-containing proprietary product, Kenalog in Orabase (KO), in the presence and absence of AZ. Pretreatment of the buccal mucosa with AZ increased the TAC disappearance permeability coefficient from 4.78+/-0.31x10(-5) cm/s to 7.12+/-0.53x10(-5) cm/s. While the TAC appearance permeability coefficient was also enhanced 3.8-fold, a 4.4-fold increase in the tissue concentration of TAC was observed. Incorporation of AZ into KO did not result in an enhanced tissue concentration of TAC, however, when the tissue was pretreated with AZ, significantly higher amounts of TAC accumulated in the tissue. Pretreatment of the buccal mucosa with AZ results in increased tissue concentrations of TAC, which may be of clinical benefit in the treatment of oral mucosal inflammatory conditions.

  8. Enhancing the buccal mucosal delivery of peptide and protein therapeutics.

    PubMed

    Caon, Thiago; Jin, Liang; Simões, Cláudia M O; Norton, Raymond S; Nicolazzo, Joseph A

    2015-01-01

    With continuing advances in biotechnology and genetic engineering, there has been a dramatic increase in the availability of new biomacromolecules, such as peptides and proteins that have the potential to ameliorate the symptoms of many poorly-treated diseases. Although most of these macromolecular therapeutics exhibit high potency, their large molecular mass, susceptibility to enzymatic degradation, immunogenicity and tendency to undergo aggregation, adsorption, and denaturation have limited their ability to be administered via the traditional oral route. As a result, alternative noninvasive routes have been investigated for the systemic delivery of these macromolecules, one of which is the buccal mucosa. The buccal mucosa offers a number of advantages over the oral route, making it attractive for the delivery of peptides and proteins. However, the buccal mucosa still exhibits some permeability-limiting properties, and therefore various methods have been explored to enhance the delivery of macromolecules via this route, including the use of chemical penetration enhancers, physical methods, particulate systems and mucoadhesive formulations. The incorporation of anti-aggregating agents in buccal formulations also appears to show promise in other mucosal delivery systems, but has not yet been considered for buccal mucosal drug delivery. This review provides an update on recent approaches that have shown promise in enhancing the buccal mucosal transport of macromolecules, with a major focus on proteins and peptides.

  9. Enhancing chemical reactions

    DOEpatents

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  10. Smoking during radiotherapy for head and neck cancer and acute mucosal reaction

    PubMed Central

    Szeszko, Beata; Osowiecka, Karolina; Rucińska, Monika; Wasilewska-Teśluk, Ewa; Gliński, Krzysztof; Kępka, Lucyna

    2015-01-01

    Aim We compared the incidence of RTOG/EORTC grade III and higher acute mucositis in patients with head and neck cancer who continued to smoke during radiotherapy with those who quit smoking. Background There are conflicting data on the relationship between smoking during radiotherapy and the severity of acute mucosal reaction. More studies dealing with this issue are needed. Materials and methods Among 136 patients receiving curative radio(chemo)therapy, 37 (27%) declared that they had not quit smoking during radiotherapy. The intensity of mucositis was scored daily by a nurse and weekly by a physician using the RTOG/EORTC scale. The main end-point of the study was the highest observed RTOG/EORTC grade of mucositis. Results Patients who smoked during radiotherapy (smokers) were younger than their counterparts who quit smoking (non-smokers), p = 0.06. There were no other differences in the baseline characteristics between smokers and non-smokers. Grade III/IV acute mucositis was observed in 43.5% of all patients. The percentage of patients with grade III/IV acute mucositis was similar in smokers and non-smokers (46% vs. 42%, p = 0.71). Nine patients (smokers [13.5%]; non-smokers [4%], p = 0.05) required prolonged hospitalization to heal mucositis. Conclusions In the whole group, smoking during radiotherapy was not related to acute mucosal toxicity evaluated as the rate of the highest observed grade of mucositis. PMID:26109918

  11. Use of inactivated E.Coli enterotoxins to enhance respiratory mucosal adjuvanticity during vaccination in swine

    USDA-ARS?s Scientific Manuscript database

    In order to augment responses to respiratory vaccines in swine, various adjuvants were intranasally co-administered with an antigen to pigs. Detoxified E. coli enterotoxins LTK63 and LTR72 enhanced mucosal and systemic immunity to the model peptide, exhibiting their efficacy as mucosal adjuvants for...

  12. Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers

    PubMed Central

    Lin, Hwai-Jeng; Lo, Wen-Ching; Perng, Chin-Lin; Tseng, Guan-Ying; Li, Anna Fen-Yau; Ou, Yueh-Hsing

    2005-01-01

    AIM: Helicobacter pylori (H pylori) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosal polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers. METHODS: In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosal polymerase chain reaction for detecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosal polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2 and cag A. RESULTS: Between October 2000 and April 2002, 88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81

  13. IL-33 targeting attenuates intestinal mucositis and enhances effective tumor chemotherapy in mice.

    PubMed

    Guabiraba, R; Besnard, A G; Menezes, G B; Secher, T; Jabir, M S; Amaral, S S; Braun, H; Lima-Junior, R C P; Ribeiro, R A; Cunha, F Q; Teixeira, M M; Beyaert, R; Graham, G J; Liew, F Y

    2014-09-01

    Intestinal damage and severe diarrhea are serious side effects of cancer chemotherapy and constrain the usage of most such therapies. Here we show that interleukin-33 (IL-33) mediates the severe intestinal mucositis in mice treated with irinotecan (CPT-11), a commonly used cancer chemotherapeutic agent. Systemic CPT-11 administration led to severe mucosal damage, diarrhea, and body weight loss concomitant with the induction of IL-33 in the small intestine (SI). This mucositis was markedly reduced in mice deficient in the IL-33R (ST2(-/-)). Moreover, recombinant IL-33 exacerbated the CPT-11-induced mucositis, whereas IL-33 blockade with anti-IL-33 antibody or soluble ST2 markedly attenuated the disease. CPT-11 treatment increased neutrophil accumulation in the SI and adhesion to mesenteric veins. Supernatants from SI explants treated with CPT-11 enhanced transmigration of neutrophils in vitro in an IL-33-, CXCL1/2-, and CXCR2-dependent manner. Importantly, IL-33 blockade reduced mucositis and enabled prolonged CPT-11 treatment of ectopic CT26 colon carcinoma, leading to a beneficial outcome of the chemotherapy. These results suggest that inhibition of the IL-33/ST2 pathway may represent a novel approach to limit mucositis and thus improve the effectiveness of chemotherapy.

  14. Image-enhanced bronchoscopic evaluation of bronchial mucosal microvasculature in COPD

    PubMed Central

    Fathy, Eman Mahmoud; Shafiek, Hanaa; Morsi, Tamer S; El Sabaa, Bassma; Elnekidy, Abdelaziz; Elhoffy, Mohamed; Atta, Mohamed Samy

    2016-01-01

    Background Bronchial vascular remodeling is an underresearched component of airway remodeling in COPD. Image-enhanced bronchoscopy may offer a less invasive method for studying bronchial microvasculature in COPD. Objectives To evaluate endobronchial mucosal vasculature and changes in COPD by image-enhanced i-scan3 bronchoscopy and correlate them pathologically by analyzing bronchial mucosal biopsies. Methods This case–control study analyzed 29 COPD patients (41.4% Global initiative for chronic Obstructive Lung Disease B [GOLD B] and 58.6% GOLD D) and ten healthy controls admitted at Alexandria Main University Hospital, Egypt. Combined high-definition white light bronchoscopy (HD WLB) with i-scan3 was used to evaluate endobronchial mucosal microvasculature. The vascularity was graded according to the level of mucosal red discoloration (ie, endobronchial erythema) from decreased discoloration to normal, mild, moderate, and severe increased red discoloration (G−1, G0, G+1, G+2, and G+3, respectively) and scored by three bronchoscopists independently. Bronchial mucosal biopsies were taken for microvascular density counting using anti-CD34 antibody as angiogenesis marker. Results Different grades of endobronchial erythema were observed across/within COPD patients using combined HD WLB + i-scan3, with significant agreement among scorers (P=0.031; median score of G+1 [G−1–G+2]) being higher in GOLD D (P=0.001). Endobronchial erythema significantly correlated with COPD duration, exacerbation frequency, and body mass index (P<0.05). Angiogenesis was significantly decreased among COPD patients versus controls (10.6 [8–13.3] vs 14 [11–17.1]; P=0.02). Mucosal surface changes (including edema, atrophy, and nodules) were better visualized by the combined HD WLB + i-scan3 rather than HD WLB alone. Conclusion Combined HD WLB + i-scan3 seems to be valuable in evaluating mucosal microvasculature and surface changes in COPD, which may represent vasodilatation rather than

  15. Freeze Enhanced Halate Halide Reactions

    NASA Astrophysics Data System (ADS)

    Newberg, J. T.; Weaver, K.; Broderick, A.

    2014-12-01

    Relatively little is known about halate ion species (XO3-; X = I, Br, Cl) in atmospheric condensed phases. It was initial thought that iodate was a terminal stable species upon iodide oxidation. However, it is becoming increasingly recognized that reactions involving iodate can lead to reactive iodine, and this chemistry is accelerated under acidic conditions. The environmental concentrations and chemistry of bromate and chlorate are largely unexplored in environmental ices. We present results from a series of aqueous phase halate ion reactions with halides under acidic conditions, showing that the kinetics are strongly enhanced upon freezing. The products of these reactions are reactive halogens, which have important implications to marine boundary layer chemistry.

  16. Enhancement of Mucosal Immunization with Virus-Like Particles of Simian Immunodeficiency Virus

    PubMed Central

    Kang, Sang-Moo; Compans, Richard W.

    2003-01-01

    Cholera toxin (CT) is the most potent known mucosal adjuvant, but its toxicity precludes its use in humans. Here, in an attempt to develop safe and effective mucosal adjuvants, we compared immune responses to simian immunodeficiency virus (SIV) virus-like particles (VLPs) after intranasal coimmunization with RANTES, CpG oligodeoxynucleotides (ODN), or CT. Antibody analysis demonstrated that RANTES and CpG ODN had capacities for mucosal adjuvanticity, i.e., for enhancing serum and vaginal antibodies specific to SIV Env, similar to those for CT. RANTES and CpG ODN skewed serum antibodies predominantly to the immunoglobulin G2a isotype. Most importantly, RANTES and CpG ODN were more effective than CT in increasing neutralizing titers of both serum and vaginal antibodies. After intranasal coadministration with VLPs, RANTES or CpG ODN also induced increased levels of gamma interferon (IFN-γ)-producing lymphocyte and cytotoxic T-lymphocyte activities in both spleen and lymph nodes but did not increase the levels of interleukin-4-producing lymphocytes. The results suggest that RANTES and CpG ODN enhance immune responses in a T-helper-cell-type-1 (Th1)-oriented manner and that they can be used as effective mucosal adjuvants for enhancing both humoral and cellular immune responses in the context of VLPs, which are particulate antigens. PMID:12610137

  17. Separate effects of irradiation and of graft-versus-host reaction on rat mucosal mast cells.

    PubMed Central

    Cummins, A G; Munro, G H; Huntley, J F; Miller, H R; Ferguson, A

    1989-01-01

    T cell mediated immune responses in the gut can produce enteropathy and malabsorption. We have investigated the relevance of mucosal mast cells (MMC) to the mechanisms of this enteropathy by using graft-versus-host reaction (GvHR) in the rat as a model of mucosal delayed type hypersensitivity. Measurements of mucosal architecture, intraepithelial lymphocytes (IEL) and MMC counts were performed in control and experimental rats, and release of rat mast cell protease II (RMCPII) into the bloodstream was used as an index of MMC activation. In unirradiated rats, jejunal MMC count was increased on day 14 of the GvHR (mean 272/mm2 v 182 in controls, p less than 0.01), as was serum RMCPII (p less than 0.01). Irradiated rats (4.5 Gy, reconstituted with isogeneic spleen cells) had low counts of IEL and crypt hyperplasia seven to 14 days after irradiation. Irradiated rats with GvHR (induced by ip injection of parental strain spleen cells) and studied on days 7, 10 and 14, had significant enteropathy with longer crypts and higher CCPR than matched irradiated animals (p less than 0.05 on day 14 when compared with irradiation alone). Intraepithelial lymphocytes counts, however, reflected only the effect of radiation. Irradiation, with or without GvHR, led to the virtual disappearance of jejunal MMC, undetectable jejunal RMCPII and very low levels of RMCPII in serum (all p less than 0.01 when compared with unirradiated controls). These experiments show that there is a modest expansion in jejunal MMC in unirradiated rats with semiallogeneic GvHR, whereas irradiation, alone or associated with GvHR, profoundly depletes MMC for at least two weeks. The enteropathy of GvHR can evolve in the virtual absence of MMC. PMID:2707634

  18. Enhancement in gastric mucosal epidermal growth factor receptor expression by sulglycotide.

    PubMed

    Slomiany, B L; Piotrowski, J; Czajkowski, A; Murty, V L; Majka, J; Slomiany, A

    1994-05-01

    The effect of intragastric administration of sulglycotide, a cytoprotective sulfated glycopeptide, on the expression of gastric mucosal epidermal growth factor receptor was investigated. The experiments were conducted with groups of rats, one receiving twice daily for 5 consecutive days a dose of 200mg/kg sulglycotide, and the other only vehicle. Mucosal cell membranes were isolated from the stomachs at 16, 40 and 88h after the last dose, and used for EGF receptor assays. The binding assays revealed a marked increase in mucosal EGF receptor expression with sulglycotide. Compared to the controls, the sulglycotide-treated group showed a 4-fold increase in the EGF receptor expression at 16h after the last dose of sulglycotide, a 4.7-fold increase in the EGF receptor was observed by the 40h, and a 4.2-fold increase was still evident at 88h following the treatment. The results demonstrate that sulglycotide exhibits remarkable ability to enhance the gastric mucosal expression of EGF receptor.

  19. Enhancement in gastric mucosal EGF and PDGF receptor expression with ulcer healing by sulglycotide.

    PubMed

    Piotrowski, J; Majka, J; Sano, S; Nowak, P; Murty, V L; Slomiany, A; Slomiany, B L

    1995-07-01

    1. The effect of an antiulcer agent, sulglycotide, on mucosal expression of EGF and PDGF receptors with chronic ulcer healing was investigated. 2. Rats with experimentally-induced gastric ulcers were treated twice daily for 14 consecutive days, either with sulglycotide at 200 mg/kg or vehicle, and at different stages of treatment used for quantitation of gastric mucosal EGF and PDGF receptors. 3. The ulcer healing was accompanied by an increase in mucosal expression of both types of receptors. A 1.8-fold increase in EGF and 3.1-fold increase in PDGF receptors occurred by the 4th day following the development of ulcer and reached a maximum of 2.4-3.9-fold increase by the 10-14th day. 4. Treatment with sulglycotide caused accelerated ulcer healing accompanied by a significant enhancement in the receptors expression. A 2.3- and 3.6-fold increase in EGF and PDGF receptor expression occurred by the 4th day of sulglycotide treatment, reaching a 5.5- and 5.6-fold respective increase by the 10th day when the ulcer essentially healed. 5. The results attest to the ability of sulglycotide to stimulate the gastric mucosal proliferative activities associated with ulcer healing.

  20. CTA1: Purified and display onto gram-positive enhancer matrix (GEM) particles as mucosal adjuvant.

    PubMed

    Zhang, Yuanpeng; Yu, Xiaoming; Hou, Liting; Chen, Jin; Li, Pengcheng; Qiao, Xuwen; Zheng, Qisheng; Hou, Jibo

    2017-09-01

    The A1 subunit of cholera toxin (CTA1) retains the adjuvant function of CT, without its toxic side effects, making the molecule a promising mucosal adjuvant. However, the methods required to obtain a pure product are both complicated and expensive, constricting its potential commercial applicability. Here, we fused the peptidoglycan binding domain (PA) to the C-terminus of CTA1, which enabled the fusion protein to be expressed by Bacillus subtilis, and secreted into the culture medium. CTA1 was then purified and displayed on GEM particles using a one step process, which resulted in the formation of CTA1-GEM complexes. Next, the CTA1-GEM complexes were used as an adjuvant to enhance the immune responses of mice to the influenza subunit vaccine. It was observed that the CTA1-GEM complexes enhanced specific systemic (IgG) and mucosal (IgA) immune responses against antigen, and induced cellular immune responses as well. The data presented here suggests that CTA1-GEM complexes can serve as a viable mucosal adjuvant. Copyright © 2017. Published by Elsevier Inc.

  1. Neutrophil Interactions with Epithelial Expressed ICAM-1 Enhances Intestinal Mucosal Wound Healing

    PubMed Central

    Sumagin, R; Brazil, JC; Nava, P; Nishio, H; Alam, A; Luissint, AC; Weber, DA; Neish, AS; Nusrat, A; Parkos, CA

    2015-01-01

    A characteristic feature of gastrointestinal tract inflammatory disorders, such as inflammatory bowel disease, is polymorphonuclear neutrophil (PMN) transepithelial migration (TEM) and accumulation in the gut lumen. PMN accumulation within the intestinal mucosa contributes to tissue injury. While epithelial infiltration by large numbers of PMNs results in mucosal injury, we found that PMN interactions with luminal epithelial membrane receptors may also play a role in wound healing. Intercellular adhesion molecule-1 (ICAM-1) is a PMN ligand that is upregulated on apical surfaces of intestinal epithelial cells under inflammatory conditions. In our study, increased expression of ICAM-1 resulted in enhanced PMN binding to the apical epithelium, which was associated with reduced PMN apoptosis. Following TEM, PMN adhesion to ICAM-1 resulted in activation of Akt and β-catenin signaling, increased epithelial-cell proliferation, and wound healing. Such responses were ICAM-1 dependent as engagement of epithelial ICAM-1 by antibody-mediated cross-linking yielded similar results. Furthermore, using an in-vivo biopsy-based, colonic-mucosal-injury model, we demonstrated epithelial ICAM-1 plays an important role in activation of epithelial Akt and β-catenin signaling and wound healing. These findings suggest that post-migrated PMNs within the intestinal lumen can regulate epithelial homeostasis, thereby identifying ICAM-1 as a potential therapeutic target for promoting mucosal wound healing. PMID:26732677

  2. Neutrophil interactions with epithelial-expressed ICAM-1 enhances intestinal mucosal wound healing.

    PubMed

    Sumagin, R; Brazil, J C; Nava, P; Nishio, H; Alam, A; Luissint, A C; Weber, D A; Neish, A S; Nusrat, A; Parkos, C A

    2016-09-01

    A characteristic feature of gastrointestinal tract inflammatory disorders, such as inflammatory bowel disease, is polymorphonuclear neutrophil (PMN) transepithelial migration (TEM) and accumulation in the gut lumen. PMN accumulation within the intestinal mucosa contributes to tissue injury. Although epithelial infiltration by large numbers of PMNs results in mucosal injury, we found that PMN interactions with luminal epithelial membrane receptors may also play a role in wound healing. Intercellular adhesion molecule-1 (ICAM-1) is a PMN ligand that is upregulated on apical surfaces of intestinal epithelial cells under inflammatory conditions. In our study, increased expression of ICAM-1 resulted in enhanced PMN binding to the apical epithelium, which was associated with reduced PMN apoptosis. Following TEM, PMN adhesion to ICAM-1 resulted in activation of Akt and β-catenin signaling, increased epithelial-cell proliferation, and wound healing. Such responses were ICAM-1 dependent as engagement of epithelial ICAM-1 by antibody-mediated cross-linking yielded similar results. Furthermore, using an in-vivo biopsy-based, colonic-mucosal-injury model, we demonstrated epithelial ICAM-1 has an important role in activation of epithelial Akt and β-catenin signaling and wound healing. These findings suggest that post-migrated PMNs within the intestinal lumen can regulate epithelial homeostasis, thereby identifying ICAM-1 as a potential therapeutic target for promoting mucosal wound healing.

  3. Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

    PubMed Central

    Kohgadai, Nargis; Müller, Janis A.; Laustsen, Anders; Thavachelvam, Karthiga; Stürzel, Christina M.; Jones, Jennifer J.; Somsouk, Ma; Garcia, Maurice M.; Smith, James F.; Greenblatt, Ruth M.; Münch, Jan; Jakobsen, Martin R.; Giudice, Linda C.; Greene, Warner C.; Roan, Nadia R.

    2017-01-01

    Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethra, and intestines significantly increase HIV infection of CD4+ T cells–by up to 37-fold for R5-tropic HIV and 100-fold for X4-tropic HIV–without themselves becoming infected. Fibroblasts were more efficient than dendritic cells at trans-infection and mediate this response in the absence of the DC-SIGN and Siglec-1 receptors. In comparison, mucosal epithelial cells secrete antivirals and inhibit HIV infection. These data suggest that breaches in the epithelium allow external or luminal HIV to escape an antiviral environment to access the infection-favorable environment of the stromal fibroblasts, and suggest that resident fibroblasts have a central, but previously unrecognized, role in HIV acquisition at mucosal sites. Inhibiting fibroblast-mediated enhancement of HIV infection should be considered as a novel prevention strategy. PMID:28207890

  4. Bifidobacterium bifidum Extracellular Sialidase Enhances Adhesion to the Mucosal Surface and Supports Carbohydrate Assimilation.

    PubMed

    Nishiyama, Keita; Yamamoto, Yuji; Sugiyama, Makoto; Takaki, Takashi; Urashima, Tadasu; Fukiya, Satoru; Yokota, Atsushi; Okada, Nobuhiko; Mukai, Takao

    2017-10-03

    Bifidobacterium is a natural inhabitant of the human gastrointestinal (GI) tract. We studied the role of the extracellular sialidase (SiaBb2, 835 amino acids [aa]) from Bifidobacterium bifidum ATCC 15696 in mucosal surface adhesion and carbohydrate catabolism. Human milk oligosaccharides (HMOs) or porcine mucin oligosaccharides as the sole carbon source enhanced B. bifidum growth. This was impaired in a B. bifidum ATCC 15696 strain harboring a mutation in the siabb2 gene. Mutant cells in early to late exponential growth phase also showed decreased adhesion to human epithelial cells and porcine mucin relative to the wild-type strain. These results indicate that SiaBb2 removes sialic acid from HMOs and mucin for metabolic purposes and may promote bifidobacterial adhesion to the mucosal surface. To further characterize SiaBb2-mediated bacterial adhesion, we examined the binding of His-tagged recombinant SiaBb2 peptide to colonic mucins and found that His-SiaBb2 as well as a conserved sialidase domain peptide (aa 187 to 553, His-Sia) bound to porcine mucin and murine colonic sections. A glycoarray assay revealed that His-Sia bound to the α2,6-linked but not to the α2,3-linked sialic acid on sialyloligosaccharide and blood type A antigen [GalNAcα1-3(Fucα1-2)Galβ] at the nonreducing termini of sugar chains. These results suggest that the sialidase domain of SiaBb2 is responsible for this interaction and that the protein recognizes two distinct carbohydrate structures. Thus, SiaBb2 may be involved in Bifidobacterium-mucosal surface interactions as well as in the assimilation of a variety of sialylated carbohydrates.IMPORTANCE Adhesion to the host mucosal surface and carbohydrate assimilation are important for bifidobacterium colonization and survival in the host gastrointestinal tract. In this study, we investigated the mechanistic basis for B. bifidum extracellular sialidase (SiaBb2)-mediated adhesion. SiaBb2 cleaved sialyl-human milk oligosaccharides and mucin

  5. Enhancement of Microbiota in Healthy Macaques Results in Beneficial Modulation of Mucosal and Systemic Immune Function1

    PubMed Central

    Manuzak, Jennifer A.; Hensley-McBain, Tiffany; Zevin, Alexander S.; Miller, Charlene; Cubas, Rafael; Agricola, Brian; Gile, Jill; Richert-Spuhler, Laura; Patilea, Gabriela; Estes, Jacob D.; Langevin, Stanley; Reeves, R. Keith; Haddad, Elias K.; Klatt, Nichole R.

    2016-01-01

    Given the critical role of mucosal surfaces in susceptibility to infection, it is imperative that effective mucosal responses are induced when developing efficacious vaccines and prevention strategies for infection. Modulating the microbiota in the gastrointestinal (GI) tract through the use of probiotics (PBio) is a safe and well-tolerated approach to enhance mucosal and overall health. We assessed the longitudinal impact of daily treatment with the VSL#3 probiotic on cellular and humoral immunity and inflammation in healthy macaques. PBio therapy resulted in significantly increased frequencies of B cells expressing IgA in the colon and lymph node (LN), likely due to significantly increased LN T follicular helper cell (Tfh) frequencies and LN follicles. Increased frequencies of IL-23+ antigen presenting cells (APCs) in the colon were found post-PBio treatment, which correlated with LN Tfh. Finally, VSL#3 significantly down-modulated the response of TLR2, TLR3, TLR4 and TLR9-expressing HEK293 cells to stimulation with Pam3CSK4, Poly(I:C), LPS and ODN2006, respectively. These data provide a mechanism for the beneficial impact of PBio on mucosal health and implicates the use of PBio therapy in the context of vaccination or preventative approaches to enhance protection from mucosal infection by improving immune defenses at the mucosal portal of entry. PMID:26826246

  6. Oral Mucosal Injection of a Local Anesthetic Solution Containing Epinephrine Enhances Muscle Relaxant Effects of Rocuronium

    PubMed Central

    Ninomiya, Asako; Terakawa, Yui; Matsuura, Nobuyuki; Ichinohe, Tatsuya; Kaneko, Yuzuru

    2012-01-01

    The purpose of this study was to examine how submucosal injection of a clinically relevant dose of a lidocaine hydrochloride solution containing epinephrine affects the muscle relaxant effects of rocuronium bromide. Sixteen patients scheduled for orthognathic surgery participated in this study. All patients were induced with fentanyl citrate, a target-controlled infusion of propofol and rocuronium bromide. Anesthesia was maintained by total intravenous anesthesia. After nasotracheal intubation, an infusion of rocuronium bromide was started at 7 µg/kg/min, and the infusion rate was then adjusted to maintain a train of four (TOF) ratio at 10 to 15%. The TOF ratio just prior to oral mucosal injection of a 1% lidocaine hydrochloride solution containing 10 µg/mL epinephrine (LE) was taken as the baseline. TOF ratio was observed for 20 minutes, with 1-minute intervals following the start of injection. Mean epinephrine dose was 85.6 ± 18.6 µg and mean infusion rate of rocuronium bromide was 6.3 ± 1.6 µg/kg/min. TOF ratio began to decrease 2 minutes after the injection of LE, reached the minimum value at 3.1 ± 3.6% 12 minutes after the injection, and then began to recover. We conclude that oral mucosal injection of LE enhances the muscle relaxant effects of rocuronium bromide. PMID:22428970

  7. Oral mucosal injection of a local anesthetic solution containing epinephrine enhances muscle relaxant effects of rocuronium.

    PubMed

    Ninomiya, Asako; Terakawa, Yui; Matsuura, Nobuyuki; Ichinohe, Tatsuya; Kaneko, Yuzuru

    2012-01-01

    The purpose of this study was to examine how submucosal injection of a clinically relevant dose of a lidocaine hydrochloride solution containing epinephrine affects the muscle relaxant effects of rocuronium bromide. Sixteen patients scheduled for orthognathic surgery participated in this study. All patients were induced with fentanyl citrate, a target-controlled infusion of propofol and rocuronium bromide. Anesthesia was maintained by total intravenous anesthesia. After nasotracheal intubation, an infusion of rocuronium bromide was started at 7 µg/kg/min, and the infusion rate was then adjusted to maintain a train of four (TOF) ratio at 10 to 15%. The TOF ratio just prior to oral mucosal injection of a 1% lidocaine hydrochloride solution containing 10 µg/mL epinephrine (LE) was taken as the baseline. TOF ratio was observed for 20 minutes, with 1-minute intervals following the start of injection. Mean epinephrine dose was 85.6 ± 18.6 µg and mean infusion rate of rocuronium bromide was 6.3 ± 1.6 µg/kg/min. TOF ratio began to decrease 2 minutes after the injection of LE, reached the minimum value at 3.1 ± 3.6% 12 minutes after the injection, and then began to recover. We conclude that oral mucosal injection of LE enhances the muscle relaxant effects of rocuronium bromide.

  8. Intranasal Vaccination with Murabutide Enhances Humoral and Mucosal Immune Responses to a Virus-Like Particle Vaccine

    PubMed Central

    Jackson, Erin M.; Herbst-Kralovetz, Melissa M.

    2012-01-01

    Murabutide (MB) is a synthetic immunomodulator recognized by the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) receptor on mammalian cells. MB has previously been approved for testing in multiple human clinical trials to determine its value as an antiviral therapeutic, and as an adjuvant for injected vaccines. We have found a new use for this immunomodulator; it functions as a mucosal adjuvant that enhances immunogenicity of virus-like particles (VLP) administered intranasally. MB enhanced Norwalk virus (NV) VLP-specific IgG systemically and IgA production at distal mucosal sites following intranasal (IN) vaccination. A dose escalation study identified 100 µg as the optimal MB dosage in mice, based on the magnitude of VLP-specific IgG, IgG1, IgG2a and IgA production in serum and VLP-specific IgA production at distal mucosal sites. IN vaccination using VLP with MB was compared to IN delivery VLP with cholera toxin (CT) or gardiquimod (GARD) and to parenteral VLP delivery with alum; the MB groups were equivalent to CT and GARD and superior to alum in inducing mucosal immune responses and stimulated equivalent systemic VLP-specific antibodies. These data support the further testing of MB as a potent mucosal adjuvant for inducing robust and durable antibody responses to non-replicating subunit vaccines. PMID:22855691

  9. (Laser enhanced chemical reaction studies)

    SciTech Connect

    Not Available

    1992-01-01

    Experimental studies of dynamic molecular processes are described with particular emphasis on the use of a powerful infrared diode laser probe technique developed in our laboratory. This technique allows us to determine the final states of CO{sub 2} (and other molecules) produced by collisions, photofragmentation, or chemical reactions with a spectral resolution of 0.0003 cm{sup {minus}1} and a time resolution of 10{sup {minus}7} sec. Such high spectral resolution provides a detailed picture of the vibrational and rotational states of molecules produced by these dynamic events. We have used this experimental method to probe collisions between hot hydrogen/deuterium atoms and CO{sub 2}, between O({sup 1}D) atoms and CO{sub 2}, to study the final states of DC1 molecules produced as a result of the reactions of hot Cl atoms, and to investigate the dynamics of the reaction between OH and CO molecules. Advances in our techniques over the past two years have allowed us to identify and study more than 200 final rotational states in ten different vibrational levels of CO{sub 2} encompassing all 3 normal modes, many overtones, and combination states of the molecule. We have extended the technique to probe a variety of new molecules such as OCS, N{sub 2}O, DCl, and CS{sub 2}. All of this work is aimed at providing experimental tests for polyatomic molecule potential energy surfaces, chemical transition states in complex systems, and theories of reaction dynamic in molecules with more than 3 atoms.

  10. Intragastric capsaicin enhances rat gastric acid elimination and mucosal blood flow by afferent nerve stimulation.

    PubMed Central

    Lippe, I. T.; Pabst, M. A.; Holzer, P.

    1989-01-01

    1. This study investigated the effects of intragastric capsaicin on acid output, clearance of aniline, potential difference, and morphology of the mucosa in the rat stomach. The experiments were carried out on rats anaesthetized with urethane in which the stomachs were continuously perfused with saline. 2. When the stomach was perfused with normal saline (pH approximately 6), intragastric capsaicin (32-640 microM) had no effect on the output of titratable acid. In contrast, when acid output was stimulated by pentagastrin or when the stomach was perfused with acid saline (pH 3), capsaicin reduced acid output. Acid loss which occurred during perfusion with saline of pH 2 was not significantly increased by capsaicin. This suggests that capsaicin does not enhance acid back-diffusion but facilitates acid elimination by other means. 3. The gastric clearance of [14C]-aniline, which is an indirect index of gastric mucosal blood flow, was estimated while the stomach was perfused with saline of pH 3. The clearance of aniline rose by 50-60% following intragastric administration of capsaicin (160 microM) whereas the mean arterial blood pressure was increased by about 2.5 mmHg only. Combined pretreatment of the rats with atropine, phentolamine, and propranolol did not alter the effect of capsaicin on the gastric clearance of aniline. 4. The gastric potential difference was not altered by capsaicin (160 microM) administered together with saline of pH 3. This and the finding that there were no signs of mucosal damage by light and scanning electron microscopy indicate that intragastric capsaicin does not irritate the gastric mucosa. 5. The effects of intragastric capsaicin on gastric acid output and aniline clearance and on blood pressure were absent in rats in which capsaicin-sensitive afferent neurones had been ablated by neonatal treatment with a neurotoxic dose of capsaicin, which indicates that they result from stimulation of afferent nerve endings in the stomach. It is

  11. Genetic conjugation of components in two pneumococcal fusion protein vaccines enhances paediatric mucosal immune responses.

    PubMed

    Pope, Caroline; Oliver, Elizabeth H; Ma, Jiangtao; Langton Hewer, Claire; Mitchell, Tim J; Finn, Adam

    2015-03-30

    Streptococcus pneumoniae colonises the upper respiratory tract and can cause pneumonia, meningitis and otitis media. Existing pneumococcal conjugate vaccines are expensive to produce and only protect against 13 of the 90+ pneumococcal serotypes; hence there is an urgent need for the development of new vaccines. We have shown previously in mice that pneumolysin (Ply) and a non-toxic variant (Δ6Ply) enhance antibody responses when genetically fused to pneumococcal surface adhesin A (PsaA), a potentially valuable effect for future vaccines. We investigated this adjuvanticity in human paediatric mucosal primary immune cell cultures. Adenoidal mononuclear cells (AMNC) from children aged 0-15 years (n=46) were stimulated with conjugated, admixed or individual proteins, cell viability and CD4+ T-cell proliferative responses were assessed using flow cytometry and cytokine secretion was measured using multiplex technology. Proliferation of CD4+ T-cells in response to PsaAPly, was significantly higher than responses to individual or admixed proteins (p=0.002). In contrast, an enhanced response to PsaAΔ6Ply compared to individual or admixed proteins only occurred at higher concentrations (p<0.01). Evaluation of cytotoxicity suggested that responses occurred when Ply-induced cytolysis was inhibited, either by fusion or mutation, but importantly an additional toxicity independent immune enhancing effect was also apparent as a result of fusion. Responses were MHC class II dependent and had a Th1/Th17 profile. Genetic fusion of Δ6Ply to PsaA significantly modulates and enhances pro-inflammatory CD4+ T-cell responses without the cytolytic effects of some other pneumolysoids. Membrane binding activity of such proteins may confer valuable adjuvant properties as fusion may assist Δ6Ply to deliver PsaA to the APC surface effectively, contributing to the initiation of anti-pneumococcal CD4+ T-cell immunity.

  12. Comparisons of late vaginal mucosal reactions between interstitial and conventional intracavitary brachytherapy in patients with gynecological cancer: speculation on the relation between pallor reaction and stenosis.

    PubMed

    Yoshida, Ken; Yamazaki, Hideya; Nakamura, Satoaki; Masui, Koji; Kotsuma, Tadayuki; Baek, Sung Jae; Akiyama, Hironori; Tanaka, Eiichi; Yoshioka, Yasuo

    2013-09-01

    To examine late vaginal mucosal reactions in patients following interstitial brachytherapy (ISBT) compared with that of intracavitary brachytherapy (ICBT). We introduced a modified Dische score to examine late reactions in vaginal mucosa of patients with gynecological cancer who underwent vaginal brachytherapy at 6, 12, 18, 24, 36, and 60 months after treatment. A comparison was made between patients who underwent ISBT (n=37) and those under conventional ICBT (n=63) with a median follow-up time of 41 months. The ICBT group included only patients with newly diagnosed cervical cancer, whereas the ISBT group included 17 patients with recurrent and 20 with newly-diagnosed cancer. Grade 1 reactions of bleeding and discharge were exhibited by <12% of patients. Erythema was detected in approximately 30% (mainly grade 1) of the patients. A total of two (3%) patients developed superficial ulceration after ICBT, whereas three (8%) grade 1 ulcers were detected in patients after ISBT. Telangiectasias were detected in approximately 70% (60% grade 1 and 10% grade 2) of patients. No statistically significant difference was found between the patients after ISBT and ICBT. After ISBT, patients have a higher stenosis rate than after ICBT (p=0.003). The pallor scores showed a strong correlation with stenosis (p<0.0001) and were higher in patients after ICBT than in patients after ISBT (p=0.006). After ISBT, patients exhibited milder but similar late mucosal reactions compared to those after ICBT, except the fact that the stenosis was more severe and the pallor reaction was milder in these patients. It can be, therefore, concluded that the pallor reaction is related to stenosis.

  13. Novel Mucosal DNA-MVA HIV Vaccination in Which DNA-IL-12 Plus Cholera Toxin B Subunit (CTB) Cooperates to Enhance Cellular Systemic and Mucosal Genital Tract Immunity

    PubMed Central

    Holgado, María Pía; Falivene, Juliana; Gherardi, María Magdalena

    2014-01-01

    Induction of local antiviral immune responses at the mucosal portal surfaces where HIV-1 and other viral pathogens are usually first encountered remains a primary goal for most vaccines against mucosally acquired viral infections. Exploring mucosal immunization regimes in order to find optimal vector combinations and also appropriate mucosal adjuvants in the HIV vaccine development is decisive. In this study we analyzed the interaction of DNA-IL-12 and cholera toxin B subunit (CTB) after their mucosal administration in DNA prime/MVA boost intranasal regimes, defining the cooperation of both adjuvants to enhance immune responses against the HIV-1 Env antigen. Our results demonstrated that nasal mucosal DNA/MVA immunization schemes can be effectively improved by the co-delivery of DNA-IL-12 plus CTB inducing elevated HIV-specific CD8 responses in spleen and more importantly in genital tract and genito-rectal draining lymph nodes. Remarkably, these CTL responses were of superior quality showing higher avidity, polyfunctionality and a broader cytokine profile. After IL-12+CTB co-delivery, the cellular responses induced showed an enhanced breadth recognizing with higher efficiency Env peptides from different subtypes. Even more, an in vivo CTL cytolytic assay demonstrated the higher specific CD8 T-cell performance after the IL-12+CTB immunization showing in an indirect manner its potential protective capacity. Improvements observed were maintained during the memory phase where we found higher proportions of specific central memory and T memory stem-like cells T-cell subpopulations. Together, our data show that DNA-IL-12 plus CTB can be effectively employed acting as mucosal adjuvants during DNA prime/MVA boost intranasal vaccinations, enhancing magnitude and quality of HIV-specific systemic and mucosal immune responses. PMID:25215887

  14. Enhanced Mucosal Antibody Production and Protection against Respiratory Infections Following an Orally Administered Bacterial Extract

    PubMed Central

    Pasquali, Christian; Salami, Olawale; Taneja, Manisha; Gollwitzer, Eva S.; Trompette, Aurelien; Pattaroni, Céline; Yadava, Koshika; Bauer, Jacques; Marsland, Benjamin J.

    2014-01-01

    Secondary bacterial infections following influenza infection are a pressing problem facing respiratory medicine. Although antibiotic treatment has been highly successful over recent decades, fatalities due to secondary bacterial infections remain one of the leading causes of death associated with influenza. We have assessed whether administration of a bacterial extract alone is sufficient to potentiate immune responses and protect against primary infection with influenza, and secondary infections with either Streptococcus pneumoniae or Klebsiella pneumoniae in mice. We show that oral administration with the bacterial extract, OM-85, leads to a maturation of dendritic cells and B-cells characterized by increases in MHC II, CD86, and CD40, and a reduction in ICOSL. Improved immune responsiveness against influenza virus reduced the threshold of susceptibility to secondary bacterial infections, and thus protected the mice. The protection was associated with enhanced polyclonal B-cell activation and release of antibodies that were effective at neutralizing the virus. Taken together, these data show that oral administration of bacterial extracts provides sufficient mucosal immune stimulation to protect mice against a respiratory tract viral infection and associated sequelae. PMID:25593914

  15. Distinct TRPV1- and TRPA1-based mechanisms underlying enhancement of oral ulcerative mucositis-induced pain by 5-fluorouracil.

    PubMed

    Yamaguchi, Kiichiro; Ono, Kentaro; Hitomi, Suzuro; Ito, Misa; Nodai, Tomotaka; Goto, Tetsuya; Harano, Nozomu; Watanabe, Seiji; Inoue, Hiromasa; Miyano, Kanako; Uezono, Yasuhito; Matoba, Motohiro; Inenaga, Kiyotoshi

    2016-05-01

    In many patients with cancer, chemotherapy-induced severe oral ulcerative mucositis causes intractable pain, leading to delays and interruptions in therapy. However, the pain mechanism in oral ulcerative mucositis after chemotherapy has not been extensively studied. In this study, we investigated spontaneous pain and mechanical allodynia in a preclinical model of oral ulcerative mucositis after systemic administration of the chemotherapy drug 5-fluorouracil, using our proprietary pain assay system for conscious rats. 5-Fluorouracil caused leukopenia but did not induce pain-related behaviors. After 5-fluorouracil administration, oral ulcers were developed with topical acetic acid treatment. Compared with saline-treated rats, 5-fluorouracil-exposed rats showed more severe mucositis with excessive bacterial loading due to a lack of leukocyte infiltration, as well as enhancements of spontaneous pain and mechanical allodynia. Antibacterial drugs, the lipid A inhibitor polymyxin B and the TRPV1/TRPA1 channel pore-passing anesthetic QX-314, suppressed both the spontaneous pain and the mechanical allodynia. The cyclooxygenase inhibitor indomethacin and the TRPV1 antagonist SB-366791 inhibited the spontaneous pain, but not the mechanical allodynia. In contrast, the TRPA1 antagonist HC-030031 and the N-formylmethionine receptor FPR1 antagonist Boc MLF primarily suppressed the mechanical allodynia. These results suggest that 5-fluorouracil-associated leukopenia allows excessive oral bacterial infection in the oral ulcerative region, resulting in the enhancement of spontaneous pain through continuous TRPV1 activation and cyclooxygenase pathway, and mechanical allodynia through mechanical sensitization of TRPA1 caused by neuronal effects of bacterial toxins. These distinct pain mechanisms explain the difficulties encountered with general treatments for oral ulcerative mucositis-induced pain in patients with cancer and suggest more effective approaches.

  16. Medroxyprogesterone acetate and levonorgestrel increase genital mucosal permeability and enhance susceptibility to genital herpes simplex virus type 2 infection

    PubMed Central

    Calla, Nirk E Quispe; Miguel, Rodolfo D Vicetti; Boyaka, Prosper N; Hall-Stoodley, Luanne; Kaur, Balveen; Trout, Wayne; Pavelko, Stephen D; Cherpes, Thomas L

    2016-01-01

    Depot-medroxyprogesterone acetate (DMPA) is a hormonal contraceptive especially popular in areas with high prevalence of HIV and other sexually transmitted infections (STI). While observational studies identify DMPA as an important STI risk factor, mechanisms underlying this connection are undefined. Levonorgestrel (LNG) is another progestin used for hormonal contraception, but its effect on STI susceptibility is much less explored. Using a mouse model of genital HSV-2 infection, we herein found DMPA and LNG similarly reduced genital expression of the desmosomal cadherin desmoglein-1α (DSG1α), enhanced access of inflammatory cells to genital tissue by increasing mucosal epithelial permeability, and increased susceptibility to viral infection. Additional studies with uninfected mice revealed DMPA-mediated increases in mucosal permeability promoted tissue inflammation by facilitating endogenous vaginal microbiota invasion. Conversely, concomitant treatment of mice with DMPA and intravaginal estrogen restored mucosal barrier function and prevented HSV-2 infection. Evaluating ectocervical biopsy tissue from women before and 1 month after initiating DMPA remarkably revealed inflammation and barrier protection were altered by treatment identically to changes seen in progestin-treated mice. Together, our work reveals DMPA and LNG diminish the genital mucosal barrier; a first-line defense against all STI, but may offer foundation for new contraceptive strategies less compromising of barrier protection. PMID:27007679

  17. Medroxyprogesterone acetate and levonorgestrel increase genital mucosal permeability and enhance susceptibility to genital herpes simplex virus type 2 infection.

    PubMed

    Quispe Calla, N E; Vicetti Miguel, R D; Boyaka, P N; Hall-Stoodley, L; Kaur, B; Trout, W; Pavelko, S D; Cherpes, T L

    2016-11-01

    Depot-medroxyprogesterone acetate (DMPA) is a hormonal contraceptive especially popular in areas with high prevalence of HIV and other sexually transmitted infections (STI). Although observational studies identify DMPA as an important STI risk factor, mechanisms underlying this connection are undefined. Levonorgestrel (LNG) is another progestin used for hormonal contraception, but its effect on STI susceptibility is much less explored. Using a mouse model of genital herpes simplex virus type 2 (HSV-2) infection, we herein found that DMPA and LNG similarly reduced genital expression of the desmosomal cadherin desmoglein-1α (DSG1α), enhanced access of inflammatory cells to genital tissue by increasing mucosal epithelial permeability, and increased susceptibility to viral infection. Additional studies with uninfected mice revealed that DMPA-mediated increases in mucosal permeability promoted tissue inflammation by facilitating endogenous vaginal microbiota invasion. Conversely, concomitant treatment of mice with DMPA and intravaginal estrogen restored mucosal barrier function and prevented HSV-2 infection. Evaluating ectocervical biopsy tissue from women before and 1 month after initiating DMPA remarkably revealed that inflammation and barrier protection were altered by treatment identically to changes seen in progestin-treated mice. Together, our work reveals DMPA and LNG diminish the genital mucosal barrier; a first-line defense against all STI, but may offer foundation for new contraceptive strategies less compromising of barrier protection.

  18. Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

    DTIC Science & Technology

    2006-03-15

    in developing and applying adjuvants that can enhance mucosal immunity. Parenteral administration of aluminum ( alum ) hydroxide or phosphate (the...personal communication). However, alum adjuvant given by intranasally (i.n.) or aerosol route may cause adverse 264-410X/$ – see front matter. Published by...levels of cAMP alters ion transport, inducing secre- ion of water and chloride ions in the intestine [12]. Guided by the crystal structure of LT and by

  19. Enhanced aqueous photochemical reaction rates after freezing.

    PubMed

    Grannas, Amanda M; Bausch, Alexandra R; Mahanna, Kendell M

    2007-11-01

    Sunlit snow/ice is known to play an important role in the processing of atmospheric species, including photochemical production of NO(x), HONO, molecular halogens, alkyl halides, and carbonyl compounds, among others. It has been shown that a liquid-like (quasi-liquid or disordered) layer exists on the surface of pure ice and that this quasi-liquid layer is also found on the surface of ambient snow crystals and ice at temperatures similar to polar conditions. However, it is unclear what role the liquid-like fractions present in and on frozen water play in potential photochemical reactions, particularly with regard to organic substrates. Here, we report a detailed study of enhanced rates of photochemical nucleophilic substitution of p-nitroanisole (PNA) with pyridine, a well-characterized and commonly used actinometer system. Reaction rates were enhanced by a factor of up to approximately 40 when frozen at temperatures between 236 and 272 K. Reaction rates were dependent on temperature and solute concentration, both variables that control the nature of the liquid-like fraction in frozen water. The results obtained indicate that a major portion of the organic solutes is excluded to the liquid-like layer, significantly impacting the rate of the photochemical nucleophilic substitution reaction studied here. Also, the direct comparison of liquid-phase kinetics to reactions occurring in frozen water systems is drawn into question, indicating that a simple extrapolation of liquid-phase mechanisms to snow/ice may not be valid for certain reactions.

  20. N-succinyl chitosan as buccal penetration enhancer for delivery of herbal agents in treatment of oral mucositis.

    PubMed

    Dhawan, Neha; Kumar, Krishan; Kalia, A N; Arora, Saahil

    2014-01-01

    Oral mucositis is one of the major side effects of cancer chemotherapy (30-76%) and radiotherapy (over 50%). Current palliative treatments of oral mucositis include specialized agents like pelifermin, platelet derived factors etc. or oral hygienic agents which suffered from various drawbacks like systemic side effect, least effect owing to fast wash out of buccal mucosa, patient unfriendly delivery systems, and mere symptomatic relief. In this research work, N-succinyl chitosan gel delivery system of microemulsified eugenol, honey and sodium hyaluronate was prepared to explore their multiple and synergistic effects on various pathological factors of oral mucositis. N-succinyl chitosan was synthesized in our laboratory and loaded with microemulsified eugenol (10% v/v), honey (10% v/v) and sodium hyaluronate (0.2% w/v) to prepare orogel with optimum pH, spreadability, mucoadhesion strength, and viscosity. In vitro eugenol release from N-succinyl chitosan gel after 8 hours in PBS (pH-6.4) was found to be 87.45±0.14%, which was better in comparison to that released from chitosan gel. Ex vivo penetration studies using rat buccal mucosal tissue also suggested better J-efflux of eugenol through N-succinyl chitosan in comparison to chitosan gel with enhancement ratio (ER) of 1.71. The antimicrobial effect of N-succinyl chitosan based orogel against S. aureus and C. albicans efficacy was found to be statistically high in comparison to chitosan based orogel as well as marketed formulation of chlorhexidine (p<0.05). The N-succinyl chitosan orogel in 5-fluoro uracil induced oral mucositis animal (Wistar rats) model showed enhanced survival ratio, weight gain and high tissue regeneration activity than chitosan gel formulation within 15 days. The formulation was successful in elevating the survival and reducing the inflammation in the oral mucosa of animals compared to disease control (p<0.05) and hence suggesting the potential of N-succinyl chitosan orogel in the treatment of

  1. Competition enhances stochasticity in biochemical reactions.

    PubMed

    Firman, Taylor; Ghosh, Kingshuk

    2013-09-28

    We study stochastic dynamics of two competing complexation reactions (i) A + B↔AB and (ii) A + C↔AC. Such reactions are common in biology where different reactants compete for common resources--examples range from binding enzyme kinetics to gene expression. On the other hand, stochasticity is inherent in biological systems due to small copy numbers. We investigate the complex interplay between competition and stochasticity, using coupled complexation reactions as the model system. Within the master equation formalism, we compute the exact distribution of the number of complexes to analyze equilibrium fluctuations of several observables. Our study reveals that the presence of competition offered by one reaction (say A + C↔AC) can significantly enhance the fluctuation in the other (A + B↔AB). We provide detailed quantitative estimates of this enhanced fluctuation for different combinations of rate constants and numbers of reactant molecules that are typical in biology. We notice that fluctuations can be significant even when two of the reactant molecules (say B and C) are infinite in number, maintaining a fixed stoichiometry, while the other reactant (A) is finite. This is purely due to the coupling mediated via resource sharing and is in stark contrast to the single reaction scenario, where large numbers of one of the components ensure zero fluctuation. Our detailed analysis further highlights regions where numerical estimates of mass action solutions can differ from the actual averages. These observations indicate that averages can be a poor representation of the system, hence analysis that is purely based on averages such as mass action laws can be potentially misleading in such noisy biological systems. We believe that the exhaustive study presented here will provide qualitative and quantitative insights into the role of noise and its enhancement in the presence of competition that will be relevant in many biological settings.

  2. Photocatalytic silver enhancement reaction for gravimetric immunosensors.

    PubMed

    Seo, Hyejung; Joo, Jinmyoung; Ko, Wooree; Jung, Namchul; Jeon, Sangmin

    2010-12-17

    A novel microgravimetric immunosensor has been developed using TiO(2) nanoparticle-modified immunoassay and silver enhancement reaction. An antibody-conjugated TiO(2) nanoparticle is bound to the AFP antigen immobilized on a quartz resonator. When the nanoparticles are exposed to UV light in a silver nitrate solution, the photocatalytic reduction of silver ions results in the formation of metallic silver onto the nanoparticles and induces a decrease in the resonance frequency. The frequency change by this photocatalytic reduction reaction is three orders of magnitude larger than the change by antigen binding alone. The efficiency of the photocatalytic reaction has been found to increase with the fraction of anatase crystallites in the nanoparticles and the concentration of the AgNO(3) solution. The results highlight the potential of the photocatalytic nanoparticles for the detection of low concentrations of target molecules using gravimetric sensors.

  3. Vibrationally Enhanced Hydrogen Tunneling in Enzymatic Reactions

    NASA Astrophysics Data System (ADS)

    Bruno, William James

    1990-01-01

    Evidence for tunneling in enzymatic hydrogen transfer reactions has recently been observed. We argue that such reactions are likely to proceed via ground-state tunneling through a barrier which has been greatly shortened by thermally activated vibrational fluctuations. These fluctuations enhance the tunneling rate, cause it to depend on temperature and lead to a modest, temperature dependent "kinetic isotope effect" (KIE), which is defined to be the factor by which the reaction slows down due to isotopic substitution of the transferred hydrogen. We present a quantitative model for this mechanism which leads to a simple expression for the KIE in terms of two parameters: the tunneling action, S, and the ratio of its derivatives, S^ {'2}/S^{ ''}. This expression is used to fit the four KIE quantities measured in the bovine serum amine oxidase (BSAO) system: the hydrogen/tritium and hydrogen/deuterium KIE's and their Arrhenius slopes.

  4. Photocatalytic silver enhancement reaction for gravimetric immunosensors

    NASA Astrophysics Data System (ADS)

    Seo, Hyejung; Joo, Jinmyoung; Ko, Wooree; Jung, Namchul; Jeon, Sangmin

    2010-12-01

    A novel microgravimetric immunosensor has been developed using TiO2 nanoparticle-modified immunoassay and silver enhancement reaction. An antibody-conjugated TiO2 nanoparticle is bound to the AFP antigen immobilized on a quartz resonator. When the nanoparticles are exposed to UV light in a silver nitrate solution, the photocatalytic reduction of silver ions results in the formation of metallic silver onto the nanoparticles and induces a decrease in the resonance frequency. The frequency change by this photocatalytic reduction reaction is three orders of magnitude larger than the change by antigen binding alone. The efficiency of the photocatalytic reaction has been found to increase with the fraction of anatase crystallites in the nanoparticles and the concentration of the AgNO3 solution. The results highlight the potential of the photocatalytic nanoparticles for the detection of low concentrations of target molecules using gravimetric sensors.

  5. Sublingual delivery of insulin: effects of enhancers on the mucosal lipid fluidity and protein conformation, transport, and in vivo hypoglycemic activity.

    PubMed

    Cui, Chun-Ying; Lu, Wan-Liang; Xiao, Lan; Zhang, Shuang-Qing; Huang, Yan-Bei; Li, Sheng-Lin; Zhang, Rui-Juan; Wang, Gui-Ling; Zhang, Xuan; Zhang, Qiang

    2005-12-01

    The purposes of this study were to evaluate effects of enhancers for sublingual delivering insulin on the mucosal lipid fluidity and protein conformation, transport, and in vivo hypoglycemic activity in normal rats. The effects on sublingual mucosa, and aggregation states of insulin were estimated using fluorescence polarization, and circular dichroism method, respectively. The human immortalized oral epithelial cell monolayer was used for evaluating transport of insulin. Hydroxylpropyl-beta-cyclodextrin (HP-beta-CD), chitosan, polyethylene-polypropylene glycol, polyoxyethylene lauryl ether, polysorbate 80, egg lecithin, or oleic acid, was used as a penetration enhancer, respectively. The fluidity of sublingual mucosal lipid was markedly reduced by these enhancers excluding polysorbate 80, and the secondary structure of the mucosal proteins was also influenced by these enhancers. The hexamers of insulin were dissociated to monomers only by chitosan, polyoxyethylene lauryl ether, and egg lecithin. Nonetheless, plasma glucose levels in normal rats were significantly lowered after sublingual administration of insulin with an enhancer compared with those without an enhancer at the same time-point. The enhancing effects may be due to one or multiple factors: increasing the mucosal lipid fluidity, directly loosing the tight junction of epithelia, and dissociating the hexamers of insulin to monomers. Among these, the opened tight junction may correlate most with the enhancing effect in the mucosal permeability. Because the aggregates of insulin exist, the dissociation of the aggregates by an enhancer would benefit the permeability.

  6. AdHu5Ag85A Respiratory Mucosal Boost Immunization Enhances Protection against Pulmonary Tuberculosis in BCG-Primed Non-Human Primates

    PubMed Central

    Yu, Xuefeng; Harkness, Robin; Jiang, Rong; Li, Junqiang; Xing, Zhou; Zhu, Tao

    2015-01-01

    Persisting high global tuberculosis (TB) morbidity and mortality and poor efficacy of BCG vaccine emphasizes an urgent need for developing effective novel boost vaccination strategies following parenteral BCG priming in humans. Most of the current lead TB vaccine candidates in the global pipeline were developed for parenteral route of immunization. Compelling evidence indicates respiratory mucosal delivery of vaccine to be the most effective way to induce robust local mucosal protective immunity against pulmonary TB. However, despite ample supporting evidence from various animal models, there has been a lack of evidence supporting the safety and protective efficacy of respiratory mucosal TB vaccination in non-human primates (NHP) and humans. By using a rhesus macaque TB model we have evaluated the safety and protective efficacy of a recombinant human serotype 5 adenovirus-based TB vaccine (AdHu5Ag85A) delivered via the respiratory mucosal route. We show that mucosal AdHu5Ag85A boost immunization was safe and well tolerated in parenteral BCG-primed rhesus macaques. A single AdHu5Ag85A mucosal boost immunization in BCG-primed rhesus macaques enhanced the antigen–specific T cell responses. Boost immunization significantly improved the survival and bacterial control following M.tb challenge. Furthermore, TB-related lung pathology and clinical outcomes were lessened in BCG-primed, mucosally boosted animals compared to control animals. Thus, for the first time we show that a single respiratory mucosal boost immunization with a novel TB vaccine enhances protection against pulmonary TB in parenteral BCG-primed NHP. Our study provides the evidence for the protective potential of AdHu5Ag85A as a respiratory mucosal boost TB vaccine for human application. PMID:26252520

  7. Mucosal poly IC improves protection elicited by replicating influenza vaccines via enhanced dendritic cell function and T cell immunity

    PubMed Central

    Pérez-Girón, José V.; Belicha-Villanueva, Alan; Hassan, Ebrahim; Gómez-Medina, Sergio; Cruz, Jazmina L.G.; Lüdtke, Anja; Ruibal, Paula; Albrecht, Randy A.; García-Sastre, Adolfo; Muñoz-Fontela, César

    2014-01-01

    Live-attenuated influenza vaccines (LAIV) have the potential to generate CD8 T cell immunity that may limit the virulence of an antigenically shifted influenza strain in a population lacking protective antibodies. However, current LAIVs exert limited T cell immunity restricted to the vaccine strains. One approach to improve LAIV-induced T cell responses could be to use specific adjuvants to enhance T cell priming by respiratory dendritic cells (rDCs), but this hypothesis has not been addressed. Here we studied the effect of the toll-like receptor (TLR)-3 ligand poly IC on CD8 T cell immunity and protection elicited by LAIVs. Mucosal treatment with poly IC shortly after vaccination enhanced rDC function, CD8 T cell formation, and production of neutralizing antibodies. This adjuvant effect of poly IC was dependent on amplification of TLR3 signaling by non-hematopoietic radio-resistant cells, and enhanced mouse protection to homosubtypic as well as heterosubtypic virus challenge. Our findings indicate that mucosal TLR3 ligation may be utilized to improve CD8 T cell responses to replicating vaccines, which has implications for protection in the absence of pre-existing antibody immunity. PMID:24958904

  8. Monophosphoryl lipid A enhances nontypeable Haemophilus influenzae-specific mucosal and systemic immune responses by intranasal immunization.

    PubMed

    Iwasaki, Taro; Hirano, Takashi; Kodama, Satoru; Kadowaki, Yoshinori; Moriyama, Munehito; Kawano, Toshiaki; Suzuki, Masashi

    2017-06-01

    Acute otitis media (AOM) is one of the most common infectious diseases in children. Nontypeable Haemophilus influenzae (NTHi) is Gram-negative bacteria that are considered major pathogens of AOM and respiratory tract infections. In this study, we used monophosphoryl lipid A (MPL), a toll-like receptor (TLR) 4 agonist, as an adjuvant to induce mucosal immune responses against NTHi to enhance bacterial clearance from the nasopharynx. Mice were administered 10 μg outer membrane protein (OMP) from NTHi and 0, 10, or 20 μg MPL intranasally once a week for 3 weeks. Control mice were administered phosphate-buffered saline alone. After immunization, these mice were challenged with NTHi. At 6 and 12 h after bacterial challenge, the mice were killed and nasal washes and sera were collected. The numbers of NTHi- and OMP-specific antibodies were quantified by enzyme-linked immunosorbent assay. The MPL 10 and 20 μg group produced a significant reduction in the number of bacteria recovered from the nasopharynx at 12 h after bacterial challenge compared to the control group. OMP-specific IgA titers were also augmented in the MPL groups compared to the control and OMP groups. MPL is suitable for eliciting effective mucosal immune responses against NTHi in the nasopharynx. These results demonstrate the possibility of an adjuvant that involves stimulation of the innate immune system by TLR4 agonists such as MPL for mucosal vaccination. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Mucosal vaccines

    PubMed Central

    Nizard, Mevyn; Diniz, Mariana O; Roussel, Helene; Tran, Thi; Ferreira, Luis CS; Badoual, Cecile; Tartour, Eric

    2014-01-01

    The mucosal immune system displays several adaptations reflecting the exposure to the external environment. The efficient induction of mucosal immune responses also requires specific approaches, such as the use of appropriate administration routes and specific adjuvants and/or delivery systems. In contrast to vaccines delivered via parenteral routes, experimental, and clinical evidences demonstrated that mucosal vaccines can efficiently induce local immune responses to pathogens or tumors located at mucosal sites as well as systemic response. At least in part, such features can be explained by the compartmentalization of mucosal B and T cell populations that play important roles in the modulation of local immune responses. In the present review, we discuss molecular and cellular features of the mucosal immune system as well as novel immunization approaches that may lead to the development of innovative and efficient vaccines targeting pathogens and tumors at different mucosal sites. PMID:25424921

  10. Endogenous IL-21 regulates pathogenic mucosal CD4 T-cell responses during enhanced RSV disease in mice

    PubMed Central

    Dodd, J S; Clark, D; Muir, R; Korpis, C; Openshaw, P J M

    2013-01-01

    A role for interleukin-21 (IL-21) has recently been found in several diseases, but contribution to mucosal defences has not been described. In BALB/c mice infected with respiratory syncytial virus (RSV), IL-21 depletion had little effect in primary infection. However, depletion of mice during priming with recombinant vaccinia expressing RSV G protein (which primes RSV-specific T helper type 2 cells and causes lung eosinophilia during RSV infection) further exacerbated pathology during RSV challenge, with reduced viral clearance and impaired virus-specific serum antibody responses. This enhancement was accompanied by lymphocyte, neutrophil, and antigen-presenting cell recruitment to the lungs, with increased bronchoalveolar lavage interferon-γ and IL-17 levels. Adoptive transfer of splenic CD4 T cells from depleted mice into naive recipients replicated these effects, indicating that IL-21 mediates its effects via CD4 T cells. Endogenous IL-21, therefore, has potent and specific effects on mucosal antiviral responses, assisting viral clearance, regulating pulmonary T- and B-cell responses, and inhibiting IL-17 production. PMID:23168836

  11. Delivery of optical contrast agents using Triton-X100, part 2: enhanced mucosal permeation for the detection of cancer biomarkers

    NASA Astrophysics Data System (ADS)

    van de Ven, Anne L.; Adler-Storthz, Karen; Richards-Kortum, Rebecca

    2009-03-01

    Uniform delivery of optical contrast agents through mucosal tissue has proven a significant challenge. Topical permeation enhancers that have proven useful for skin demonstrate limited success in mucosal tissue. We sought to develop a topical permeation strategy capable of delivering tissue-impermeant molecular-specific contrast agents through mucosal epithelium in a uniform, controlled manner. We demonstrate that Triton-X100 can be utilized to deliver targeted and untargeted optical contrast agents through freshly excised normal mucosal epithelium and epithelial cancer. Macromolecules up to 150 kDa in size were successfully delivered via transcellular and paracellular routes. The depth of Triton-mediated permeation was modulated by varying the treatment time and concentration. Uniform epithelial penetration to a depth of 500 μm was achieved in ~1.5 h for molecules of 40 kDa or less. Larger optical probes required longer treatment times. Coadministration of molecular-specific contrast agents with Triton-X100 treatment facilitated simultaneous labeling of biomarkers on the cell membrane, in the cytoplasm, and in the nucleus with high specificity. Together, these data suggest that Triton-X100 is a promising topical permeation enhancer for mucosal delivery of tissue-impermeant molecular-specific optical contrast agents.

  12. Polymerase chain reaction-based method for the identification of Leishmania (Viannia) braziliensis and Leishmania (Viannia) guyanensis in mucosal tissues conserved in paraffin.

    PubMed

    Prestes, Suzane Ribeiro; Guerra, Jorge Augusto de Oliveira; Romero, Gustavo Adolfo Sierra; Magalhaes, Laylah Kelre Costa; Santana, Rosa Amelia Gonçalves; Maciel, Marcel Gonçalves; Custódio, Ana; Barbosa, Maria das Graças Vale; Silveira, Henrique

    2015-01-01

    In the Americas, mucosal leishmaniasis is primarily associated with infection by Leishmania (Viannia) braziliensis. However, Leishmania (Viannia) guyanensis is another important cause of this disease in the Brazilian Amazon. In this study, we aimed at detecting Leishmaniadeoxyribonucleic acid (DNA) within paraffin-embedded fragments of mucosal tissues, and characterizing the infecting parasite species. We evaluated samples collected from 114 patients treated at a reference center in the Brazilian Amazon by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses. Direct examination of biopsy imprints detected parasites in 10 of the 114 samples, while evaluation of hematoxylin and eosin-stained slides detected amastigotes in an additional 17 samples. Meanwhile, 31/114 samples (27.2%) were positive for Leishmania spp. kinetoplast deoxyribonucleic acid (kDNA) by PCR analysis. Of these, 17 (54.8%) yielded amplification of the mini-exon PCR target, thereby allowing for PCR-RFLP-based identification. Six of the samples were identified as L. (V.) braziliensis, while the remaining 11 were identified as L. (V.) guyanensis. The results of this study demonstrate the feasibility of applying molecular techniques for the diagnosis of human parasites within paraffin-embedded tissues. Moreover, our findings confirm that L. (V.) guyanensisis a relevant causative agent of mucosal leishmaniasis in the Brazilian Amazon.

  13. Aluminum enhances inflammation and decreases mucosal healing in experimental colitis in mice

    PubMed Central

    Pineton de Chambrun, G; Body-Malapel, M; Frey-Wagner, I; Djouina, M; Deknuydt, F; Atrott, K; Esquerre, N; Altare, F; Neut, C; Arrieta, M C; Kanneganti, T-D; Rogler, G; Colombel, J-F; Cortot, A; Desreumaux, P; Vignal, C

    2014-01-01

    The increasing incidence of inflammatory bowel diseases (IBDs) in developing countries has highlighted the critical role of environmental pollutants as causative factors in their pathophysiology. Despite its ubiquity and immune toxicity, the impact of aluminum in the gut is not known. This study aimed to evaluate the effects of environmentally relevant intoxication with aluminum in murine models of colitis and to explore the underlying mechanisms. Oral administration of aluminum worsened intestinal inflammation in mice with 2,4,6-trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis and chronic colitis in interleukin 10-negative (IL10−/−) mice. Aluminum increased the intensity and duration of macroscopic and histologic inflammation, colonic myeloperoxidase activity, inflammatory cytokines expression, and decreased the epithelial cell renewal compared with control animals. Under basal conditions, aluminum impaired intestinal barrier function. In vitro, aluminum induced granuloma formation and synergized with lipopolysaccharide to stimulate inflammatory cytokines expression by epithelial cells. Deleterious effects of aluminum on intestinal inflammation and mucosal repair strongly suggest that aluminum might be an environmental IBD risk factor. PMID:24129165

  14. Enhancement of mucosal immune responses in chickens by oral administration of cysteamine.

    PubMed

    Yang, Q; Lian, G; Gong, X

    2007-07-01

    Somatostatin, a tetradecapeptide originally isolated from the hypothalamus, can exert an inhibitory effect on the secretion of growth hormone by the anterior pituitary gland. In addition to endocrine organs, somatostatin is also present in the digestive tract and immune organs. In lymphoid tissues, somatostatin appears to play a role in the modulation of the immune response. Cysteamine (CS) is a sulfhydryl reducing agent that is known as a depletory agent of somatostatin. To evaluate its effects on chicken mucosal immune responses, CS was administrated orally to 1-wk-old broilers (40 mg/kg) that were immunized orally with Newcastle disease attenuated vaccine (NDV). The number of IgA-positive cells and intestinal intraepithelial lymphocytes (iIEL) in duodenum and jejunum were examined at 3-, 5-, and 7-wk posttreatment and immunization. The number of somatostatin-positive cells and relative amounts of somatostatin mRNA were also examined in the duodenum. The number of somatostatin-positive cells in the duodenum was reduced (P < 0.05) after CS treatment. In broilers receiving CS and NDV treatment (CS+NDV) the level of IgA-positive cells and iIEL in the duodenum and jejunum was increased (P < 0.05) at 3 and 5 wk posttreatment. The expression of somatostatin mRNA increased (P < 0.05) compared with that of the control group at 5 wk after immunization in broilers receiving CS+NDV or NDV alone. The results suggest that CS can induce proliferation and differentiation of IgA-positive cells and iIEL in the intestinal mucosa of chickens by reducing the number of somatostatin-positive cells.

  15. Chronic ethanol feeding promotes azoxymethane and dextran sulfate sodium-induced colonic tumorigenesis potentially by enhancing mucosal inflammation.

    PubMed

    Shukla, Pradeep K; Chaudhry, Kamaljit K; Mir, Hina; Gangwar, Ruchika; Yadav, Nikki; Manda, Bhargavi; Meena, Avtar S; Rao, RadhaKrishna

    2016-03-07

    Alcohol consumption is one of the major risk factors for colorectal cancer. However, the mechanism involved in this effect of alcohol is unknown. We evaluated the effect of chronic ethanol feeding on azoxymethane and dextran sulfate sodium (AOM/DSS)-induced carcinogenesis in mouse colon. Inflammation in colonic mucosa was assessed at a precancerous stage by evaluating mucosal infiltration of neutrophils and macrophages, and analysis of cytokine and chemokine gene expression. Chronic ethanol feeding significantly increased the number and size of polyps in colon of AOM/DSS treated mice. Confocal microscopic and immunoblot analyses showed a significant elevation of phospho-Smad, VEGF and HIF1α in the colonic mucosa. RT-PCR analysis at a precancerous stage indicated that ethanol significantly increases the expression of cytokines IL-1α, IL-6 and TNFα, and the chemokines CCL5/RANTES, CXCL9/MIG and CXCL10/IP-10 in the colonic mucosa of AOM/DSS treated mice. Confocal microscopy showed that ethanol feeding induces a dramatic elevation of myeloperoxidase, Gr1 and CD68-positive cells in the colonic mucosa of AOM/DSS-treated mice. Ethanol feeding enhanced AOM/DSS-induced suppression of tight junction protein expression and elevated cell proliferation marker, Ki-67 in the colonic epithelium. This study demonstrates that chronic ethanol feeding promotes colonic tumorigenesis potentially by enhancing inflammation and elevation of proinflammatory cytokines and chemokines.

  16. M cell-targeting strategy facilitates mucosal immune response and enhances protection against CVB3-induced viral myocarditis elicited by chitosan-DNA vaccine.

    PubMed

    Ye, Ting; Yue, Yan; Fan, Xiangmei; Dong, Chunsheng; Xu, Wei; Xiong, Sidong

    2014-07-31

    Efficient delivery of antigen to mucosal associated lymphoid tissue is a first and critical step for successful induction of mucosal immunity by vaccines. Considering its potential transcytotic capability, M cell has become a more and more attractive target for mucosal vaccines. In this research, we designed an M cell-targeting strategy by which mucosal delivery system chitosan (CS) was endowed with M cell-targeting ability via conjugating with a CPE30 peptide, C terminal 30 amino acids of clostridium perfringens enterotoxin (CPE), and then evaluated its immune-enhancing ability in the context of coxsackievirus B3 (CVB3)-specific mucosal vaccine consisting of CS and a plasmid encoding CVB3 predominant antigen VP1. It had shown that similar to CS-pVP1, M cell-targeting CPE30-CS-pVP1 vaccine appeared a uniform spherical shape with about 300 nm diameter and +22 mV zeta potential, and could efficiently protect DNA from DNase I digestion. Mice were orally immunized with 4 doses of CPE30-CS-pVP1 containing 50 μg pVP1 at 2-week intervals and challenged with CVB3 4 weeks after the last immunization. Compared with CS-pVP1 vaccine, CPE30-CS-pVP1 vaccine had no obvious impact on CVB3-specific serum IgG level and splenic T cell immune responses, but significantly increased specific fecal SIgA level and augmented mucosal T cell immune responses. Consequently, much milder myocarditis and lower viral load were witnessed in CPE30-CS-pVP1 immunized group. The enhanced immunogenicity and immunoprotection were associated with the M cell-targeting ability of CPE30-CS-pVP1 which improved its mucosal uptake and transcytosis. Our findings indicated that CPE30-CS-pVP1 may represent a novel prophylactic vaccine against CVB3-induced myocarditis, and this M cell-targeting strategy indeed could be applied as a promising and universal platform for mucosal vaccine development.

  17. Enhancement of Sonochemical Reaction by Dual-Pulse Ultrasound

    NASA Astrophysics Data System (ADS)

    Xu, Zheng; Yasuda, Keiji

    2011-07-01

    In order to apply sonochemistry in wastewater treatment, enhancement of sonochemical reaction is necessary. Oxidation of potassium iodide and the degradation of acid orange 7 in aqueous solution using ultrasound irradiation were performed at 490 kHz. Power-modulated pulsed waves were employed and the enhancement of reaction amount was observed compared with using continuous wave. The enhancement ratio for irradiation to rigid wall was larger than that for irradiation to free surface. Moreover, the best modulated pulsed on time was experimentally determined and the effect of the superposition of pulsed waves (dual-pulse) was studied. Enhancement was also observed and calculated separately when using dual-pulse ultrasound. The enhancement upon the use of the dual-transducer was ascribed to the enlargement of sonochemical reaction field. The enhancement upon the incorporating pulsed waves was ascribed to both the reduction of reaction threshold effect and the residual acoustical pressure at the pulsed off time.

  18. POZylation: a new approach to enhance nanoparticle diffusion through mucosal barriers

    NASA Astrophysics Data System (ADS)

    Mansfield, Edward D. H.; Sillence, Katy; Hole, Patrick; Williams, Adrian C.; Khutoryanskiy, Vitaliy V.

    2015-08-01

    The increasing use of nanoparticles in the pharmaceutical industry is generating concomitant interest in developing nanomaterials that can rapidly penetrate into, and permeate through, biological membranes to facilitate drug delivery and improve the bioavailability of active pharmaceutical ingredients. Here, we demonstrate that the permeation of thiolated silica nanoparticles through porcine gastric mucosa can be significantly enhanced by their functionalization with either 5 kDa poly(2-ethyl-2-oxazoline) or poly(ethylene glycol). Nanoparticle diffusion was assessed using two independent techniques; Nanoparticle Tracking Analysis, and fluorescence microscopy. Our results show that poly(2-ethyl-2-oxazoline) and poly(ethylene glycol) have comparable abilities to enhance diffusion of silica nanoparticles in mucin dispersions and through the gastric mucosa. These findings provide a new strategy in the design of nanomedicines, by surface modification or nanoparticle core construction, for enhanced transmucosal drug delivery.The increasing use of nanoparticles in the pharmaceutical industry is generating concomitant interest in developing nanomaterials that can rapidly penetrate into, and permeate through, biological membranes to facilitate drug delivery and improve the bioavailability of active pharmaceutical ingredients. Here, we demonstrate that the permeation of thiolated silica nanoparticles through porcine gastric mucosa can be significantly enhanced by their functionalization with either 5 kDa poly(2-ethyl-2-oxazoline) or poly(ethylene glycol). Nanoparticle diffusion was assessed using two independent techniques; Nanoparticle Tracking Analysis, and fluorescence microscopy. Our results show that poly(2-ethyl-2-oxazoline) and poly(ethylene glycol) have comparable abilities to enhance diffusion of silica nanoparticles in mucin dispersions and through the gastric mucosa. These findings provide a new strategy in the design of nanomedicines, by surface modification or

  19. Cyanohydrin reactions enhance glycolytic oscillations in yeast.

    PubMed

    Hald, Bjørn Olav; Nielsen, Astrid Gram; Tortzen, Christian; Sørensen, Preben Graae

    2015-01-01

    Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here, (13)C NMR is used to confirm our previous hypothesis, that cyanide directly affects glycolytic fluxes through reaction with carbonyl-containing compounds. Intracellularly, at least 3 cyanohydrins were identified. Extracellularly, all signals could be identified and lactonitrile was found to account for ~66% of total cyanide removal. Simulations of our updated computational model show that intracellular cyanide reactions increase the amplitude of oscillations and that cyanide addition lowers [ACA] instantaneously. We conclude that cyanide provides the following means of inducing global oscillations: a) by reducing [ACAx] relative to oscillation amplitude, b) by targeting multiple intracellular carbonyl compounds during fermentation, and c) by acting as a phase resetting stimulus.

  20. Dietary phytic acid and wheat bran enhance mucosal phytase activity in rat small intestine.

    PubMed

    Lopez, H W; Vallery, F; Levrat-Verny, M A; Coudray, C; Demigné, C; Rémésy, C

    2000-08-01

    The aim of this work was to investigate the influence of dietary phytic acid (PA) on intestinal phytase activity in growing rats by in vitro determination of phytase activity in the three segments of the small intestine (duodenum, jejunum and ileum), and by in vivo intestinal perfusion of a solution rich in PA (diluted soymilk). Using the in vitro method, duodenal and jejunal activities were enhanced significantly by adaptation to purified PA (+44 and +145% respectively, compared with control rats). For the rats adapted to the wheat bran (WB) diet, the induction of intestinal phytase by the substrate compared with the control values (P < 0.001) was observed only in ileum. Using soymilk in perfusions, rats consuming PA or WB diets hydrolyzed more phytate (P < 0.001 and P < 0.05, respectively) than controls. Further, Mg absorption from diluted soymilk was not affected by food adaptation, whereas Ca absorption was greater in the PA and WB groups (P < 0.001 and P < 0.05, respectively) than in the control group. Thus, intake of pure PA by rats enhances phytase in the upper parts of the small intestine (duodenum and jejunum), whereas the WB diet activates ileal phytase. Furthermore, the induction of phytase activity is greater in magnitude in rats fed synthetic PA than that observed in rats fed the WB diet. The enhancement of phytase improves intestinal Ca absorption, thus showing the capacity of the small intestine to adapt to diets rich in PA and poor in Ca.

  1. Enhanced nasal mucosal delivery and immunogenicity of anti-caries DNA vaccine through incorporation of anionic liposomes in chitosan/DNA complexes.

    PubMed

    Chen, Liulin; Zhu, Junming; Li, Yuhong; Lu, Jie; Gao, Li; Xu, Huibi; Fan, Mingwen; Yang, Xiangliang

    2013-01-01

    The design of optimized nanoparticles offers a promising strategy to enable DNA vaccines to cross various physiological barriers for eliciting a specific and protective mucosal immunity via intranasal administration. Here, we reported a new designed nanoparticle system through incorporating anionic liposomes (AL) into chitosan/DNA (CS/DNA) complexes. With enhanced cellular uptake, the constructed AL/CS/DNA nanoparticles can deliver the anti-caries DNA vaccine pGJA-P/VAX into nasal mucosa. TEM results showed the AL/CS/DNA had a spherical structure. High DNA loading ability and effective DNA protection against nuclease were proved by gel electrophoresis. The surface charge of the AL/CS/DNA depended strongly on pH environment, enabling the intracellular release of loaded DNA via a pH-mediated manner. In comparison to the traditional CS/DNA system, our new design rendered a higher transfection efficiency and longer residence time of the AL/CS/DNA at nasal mucosal surface. These outstanding features enable the AL/CS/DNA to induce a significantly (p<0.01) higher level of secretory IgA (SIgA) than the CS/DNA in animal study, and a longer-term mucosal immunity. On the other hand, the AL/CS/DNA exhibited minimal cytotoxicity. These results suggest that the developed nanoparticles offer a potential platform for DNA vaccine packaging and delivery for more efficient elicitation of mucosal immunity.

  2. [Laser enhanced chemical reaction studies]. [Progress report

    SciTech Connect

    Not Available

    1992-04-01

    Experimental studies of dynamic molecular processes are described with particular emphasis on the use of a powerful infrared diode laser probe technique developed in our laboratory. This technique allows us to determine the final states of CO{sub 2} (and other molecules) produced by collisions, photofragmentation, or chemical reactions with a spectral resolution of 0.0003 cm{sup {minus}1} and a time resolution of 10{sup {minus}7} sec. Such high spectral resolution provides a detailed picture of the vibrational and rotational states of molecules produced by these dynamic events. We have used this experimental method to probe collisions between hot hydrogen/deuterium atoms and CO{sub 2}, between O({sup 1}D) atoms and CO{sub 2}, to study the final states of DC1 molecules produced as a result of the reactions of hot Cl atoms, and to investigate the dynamics of the reaction between OH and CO molecules. Advances in our techniques over the past two years have allowed us to identify and study more than 200 final rotational states in ten different vibrational levels of CO{sub 2} encompassing all 3 normal modes, many overtones, and combination states of the molecule. We have extended the technique to probe a variety of new molecules such as OCS, N{sub 2}O, DCl, and CS{sub 2}. All of this work is aimed at providing experimental tests for polyatomic molecule potential energy surfaces, chemical transition states in complex systems, and theories of reaction dynamic in molecules with more than 3 atoms.

  3. Optimal stretching of fluid for enhancing reaction growth

    NASA Astrophysics Data System (ADS)

    Nevins, Thomas; Kelley, Douglas

    2016-11-01

    When a biological or chemical scalar grows in flowing fluid, the resulting reacted region is dependent on both the details of the flow, and the reaction kinetics. We simultaneously film reaction state and flow in a laboratory model of reactive mixing in order to examine reactive mixing in physical, time-dependent flows. Using the excitable Belousov-Zhabotinsky (BZ) reaction, we find an optimal stretching range in which the flow enhances reaction, but larger stretching causes reaction blowout. We observe the transition from flow mostly helping to mostly blowout is not associated with the transition to turbulence, and that stretching fields (closely related to finite-time Lyapunov exponents) inside the optimal range appear to have a large effect on reaction growth rate locally. We also present estimates of the optimal stretching for BZ, and hypothesize that it is a feature exclusive to excitable reactions.

  4. A Novel Peptide for Simultaneously Enhanced Treatment of Head and Neck Cancer and Mitigation of Oral Mucositis

    PubMed Central

    Chen, Peili; Mancini, Maria; Sonis, Stephen T.; Fernandez-Martinez, Juan; Liu, Jing; Cohen, Ezra E. W.; Toback, F. Gary

    2016-01-01

    We have characterized a novel 21 amino acid-peptide derived from Antrum Mucosal Protein (AMP)-18 that mediates growth promotion of cultured normal epithelial cells and mitigates radiation-induced oral mucositis in animal models, while suppressing in vitro function of cancer cells. The objective of this study was to evaluate these dual potential therapeutic effects of AMP peptide in a clinically relevant animal model of head and neck cancer (HNC) by simultaneously assessing its effect on tumor growth and radiation-induced oral mucositis in an orthotopic model of HNC. Bioluminescent SCC-25 HNC cells were injected into the anterior tongue and tumors that formed were then subjected to focal radiation treatment. Tumor size was assessed using an in vivo imaging system, and the extent of oral mucositis was compared between animals treated with AMP peptide or vehicle (controls). Synergism between AMP peptide and radiation therapy was suggested by the finding that tumors in the AMP peptide/radiation therapy cohort demonstrated inhibited growth vs. radiation therapy-only treated tumors, while AMP peptide-treatment delayed the onset and reduced the severity of radiation therapy-induced oral mucositis. A differential effect on apoptosis appears to be one mechanism by which AMP-18 can stimulate growth and repair of injured mucosal epithelial cells while inhibiting proliferation of HNC cells. RNA microarray analysis identified pathways that are differentially targeted by AMP-18 in HNC vs. nontransformed cells. These observations confirm the notion that normal cells and tumor cells may respond differently to common biological stimuli, and that leveraging this finding in the case of AMP-18 may provide a clinically relevant opportunity. PMID:27049860

  5. Cell-Associated Flagella Enhance the Protection Conferred by Mucosally-Administered Attenuated Salmonella Paratyphi A Vaccines

    PubMed Central

    Gat, Orit; Galen, James E.; Tennant, Sharon; Simon, Raphael; Blackwelder, William C.; Silverman, David J.; Pasetti, Marcela F.; Levine, Myron M.

    2011-01-01

    Background Antibiotic-resistant Salmonella enterica serovar Paratyphi A, the agent of paratyphoid A fever, poses an emerging public health dilemma in endemic areas of Asia and among travelers, as there is no licensed vaccine. Integral to our efforts to develop a S. Paratyphi A vaccine, we addressed the role of flagella as a potential protective antigen by comparing cell-associated flagella with exported flagellin subunits expressed by attenuated strains. Methodology S. Paratyphi A strain ATCC 9150 was first deleted for the chromosomal guaBA locus, creating CVD 1901. Further chromosomal deletions in fliD (CVD 1901D) or flgK (CVD 1901K) were then engineered, resulting in the export of unpolymerized FliC, without impairing its overall expression. The virulence of the resulting isogenic strains was examined using a novel mouse LD50 model to accommodate the human-host restricted S. Paratyphi A. The immunogenicity of the attenuated strains was then tested using a mouse intranasal model, followed by intraperitoneal challenge with wildtype ATCC 9150. Results Mucosal (intranasal) immunization of mice with strain CVD 1901 expressing cell-associated flagella conferred superior protection (vaccine efficacy [VE], 90%) against a lethal intraperitoneal challenge, compared with the flagellin monomer-exporting mutants CVD 1901K (30% VE) or CVD 1901D (47% VE). The superior protection induced by CVD 1901 with its cell-attached flagella was associated with an increased IgG2a∶IgG1 ratio of FliC-specific antibodies with enhanced opsonophagocytic capacity. Conclusions Our results clearly suggest that enhanced anti-FliC antibody-mediated clearance of S. Paratyphi A by phagocytic cells, induced by vaccines expressing cell-associated rather than exported FliC, might be contributing to the vaccine-induced protection from S. Paratyphi A challenge in vivo. We speculate that an excess of IgG1 anti-FliC antibodies induced by the exported FliC may compete with the IgG2a subtype and block

  6. Mucoadhesive glycol chitosan nanoparticles for intranasal delivery of hepatitis B vaccine: enhancement of mucosal and systemic immune response.

    PubMed

    Pawar, Dilip; Jaganathan, K S

    2016-01-01

    In this study, for the first time, glycol chitosan (GC) nanoparticles (NPs) were prepared and evaluated to obtain systemic and mucosal immune responses against nasally administered hepatitis B surface antigen (HBsAg). Size, zeta potential and morphology of the NPs were investigated as a function of preparation method. NPs with high loading efficacy ( > 95%) and positively charged surface were obtained with an average particle size of approximately 200 nm. The structural integrity of HBsAg in NPs was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and further confirmed by measuring the in vitro antigenicity using an enzyme immunoassay. During in vivo studies, GC NPs showed the lowest nasal clearance rate and better mucosal uptake when compared with chitosan (CS) NPs. The immunogenicity of NPs-based delivery system(s) was assessed by measuring anti-HBsAg antibody titer in mice serum and secretions after intranasal administration. The alum-based HBsAg vaccine injected subcutaneously was used as positive control. Results indicated that alum-based HBsAg induced strong humoral but negligible mucosal immunity. However, GC NPs induced stronger immune response at both of the fronts as compared to generated by CS NPs. This study demonstrates that this newly developed system has potential for mucosal administration of vaccines.

  7. Grape seed extract dose-responsively decreases disease severity in a rat model of mucositis; concomitantly enhancing chemotherapeutic effectiveness in colon cancer cells.

    PubMed

    Cheah, Ker Yeaw; Howarth, Gordon Stanley; Bastian, Susan Elaine Putnam

    2014-01-01

    Mucositis is a serious disorder of the gastrointestinal tract that results from cancer chemotherapy. We investigated the effects of increasing grape seed extract doses on the severity of chemotherapy in a rat model and its coincident impact on chemotherapeutic effectiveness in colon cancer cells. Female Dark Agouti rats were gavaged with grape seed extract (400-1000 mg/kg) or water (day 3-11) and were injected intraperitoneally with 5-Fluorouracil (150 mg/kg) or saline (control) on day 9 to induce mucositis. Daily metabolic data were collected and rats were sacrificed on day 12. Intestinal tissues were collected for histological and myeloperoxidase analyses. Caco-2 cell viability was examined in response to grape seed extract in combination with 5-Fluorouracil by 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide) assay. Compared with 5-Fluorouracil controls, grape seed extract (400-1000 mg/kg) significantly decreased the histological damage score (P<0.05) in the jejunum. Grape seed extract (1000 mg/kg) increased jejunal crypt depth by 25% (P<0.05) in 5-Fluorouracil treated rats compared to 5-Fluorouracil controls, and attenuated the 5-Fluorouracil -induced reduction of mucosal thickness (25%, P<0.05). Grape seed extract (600 mg/kg) decreased myeloperoxidase activity by 55% (P<0.01) compared to 5-Fluorouracil controls. Grape seed extract was more effective at ameliorating 5-Fluorouracil induced intestinal injury, with effects most pronounced in the proximal jejunum. Grape seed extract (10-25 ug/mL) significantly enhanced the growth-inhibitory effects of 5-Fluorouracil by 26% (P<0.05) in Caco-2 cells and was more potent than 5-Fluorouracil at 50-100 µg/mL. Grape seed extract may represent a new therapeutic option to decrease the symptoms of intestinal mucositis while concurrently impacting on the viability of colon cancer cells.

  8. Grape Seed Extract Dose-Responsively Decreases Disease Severity in a Rat Model of Mucositis; Concomitantly Enhancing Chemotherapeutic Effectiveness in Colon Cancer Cells

    PubMed Central

    Cheah, Ker Yeaw; Howarth, Gordon Stanley; Bastian, Susan Elaine Putnam

    2014-01-01

    Objective Mucositis is a serious disorder of the gastrointestinal tract that results from cancer chemotherapy. We investigated the effects of increasing grape seed extract doses on the severity of chemotherapy in a rat model and its coincident impact on chemotherapeutic effectiveness in colon cancer cells. Design Female Dark Agouti rats were gavaged with grape seed extract (400–1000 mg/kg) or water (day 3–11) and were injected intraperitoneally with 5-Fluorouracil (150 mg/kg) or saline (control) on day 9 to induce mucositis. Daily metabolic data were collected and rats were sacrificed on day 12. Intestinal tissues were collected for histological and myeloperoxidase analyses. Caco-2 cell viability was examined in response to grape seed extract in combination with 5-Fluorouracil by 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide) assay. Results Compared with 5-Fluorouracil controls, grape seed extract (400–1000 mg/kg) significantly decreased the histological damage score (P<0.05) in the jejunum. Grape seed extract (1000 mg/kg) increased jejunal crypt depth by 25% (P<0.05) in 5-Fluorouracil treated rats compared to 5-Fluorouracil controls, and attenuated the 5-Fluorouracil -induced reduction of mucosal thickness (25%, P<0.05). Grape seed extract (600 mg/kg) decreased myeloperoxidase activity by 55% (P<0.01) compared to 5-Fluorouracil controls. Grape seed extract was more effective at ameliorating 5-Fluorouracil induced intestinal injury, with effects most pronounced in the proximal jejunum. Grape seed extract (10–25 ug/mL) significantly enhanced the growth-inhibitory effects of 5-Fluorouracil by 26% (P<0.05) in Caco-2 cells and was more potent than 5-Fluorouracil at 50–100 µg/mL. Conclusion Grape seed extract may represent a new therapeutic option to decrease the symptoms of intestinal mucositis while concurrently impacting on the viability of colon cancer cells. PMID:24465501

  9. The importance of local mucosal HIV-specific CD8(+) cytotoxic T lymphocytes for resistance to mucosal viral transmission in mice and enhancement of resistance by local administration of IL-12.

    PubMed Central

    Belyakov, I M; Ahlers, J D; Brandwein, B Y; Earl, P; Kelsall, B L; Moss, B; Strober, W; Berzofsky, J A

    1998-01-01

    Although crucial to mucosal vaccine development, the mechanisms of defense against mucosal viral infection are still poorly understood. Protection, cytotoxic T lymphocytes (CTL), and neutralizing antibodies have all been observed, but cause and effect have been difficult to determine. The ability of CTL in the mucosa to mediate protection against mucosal viral transmission has never been proven. Here, we use an HIV peptide immunogen and an HIV-1 gp160-expressing recombinant vaccinia viral intrarectal murine challenge system, in which neutralizing antibodies do not play a role, to demonstrate for the first time that long-lasting immune resistance to mucosal viral transmission can be accomplished by CD8(+) CTL that must be present in the mucosal site of exposure. The resistance is ablated by depleting CD8(+) cells in vivo and requires CTL in the mucosa, whereas systemic (splenic) CTL are shown to be unable to protect against mucosal challenge. Furthermore, the resistance as well as the CTL response can be increased by local mucosal delivery of IL-12 with the vaccine. These results imply that induction of local mucosal CTL may be critical for success of a vaccine against viruses transmitted through a mucosal route, such as HIV. PMID:9854042

  10. Enhancement of Biological Reactions on Cell Surfaces via Macromolecular Crowding

    PubMed Central

    Chapanian, Rafi; Kwan, David H.; Constantinescu, Iren; Shaikh, Fathima A.; Rossi, Nicholas A.A.; Withers, Stephen G.; Kizhakkedathu, Jayachandran N.

    2016-01-01

    The reaction of macromolecules such as enzymes and antibodies with cell surfaces is often an inefficient process, requiring large amounts of expensive reagent. Here we report a general method based on macromolecular crowding with a range of neutral polymers to enhance such reactions, using red blood cells (RBCs) as a model system. Rates of conversion of Type A and B red blood cells to universal O type by removal of antigenic carbohydrates with selective glycosidases are increased up to 400-fold in the presence of crowders. Similar enhancements are seen for antibody binding. We further explore the factors underlying these enhancements using confocal microscopy and fluorescent recovery after bleaching (FRAP) techniques with various fluorescent protein fusion partners. Increased cell-surface concentration due to volume exclusion, along with two-dimensionally confined diffusion of enzymes close to the cell surface, appear to be the major contributing factors. PMID:25140641

  11. Mucoadhesive Fenretinide Patches for Site-specific Chemoprevention of Oral Cancer: Enhancement of Oral Mucosal Permeation of Fenretinide by Co-incorporation of Propylene Glycol and Menthol

    PubMed Central

    Wu, Xiao; Desai, Kashappa-Goud H.; Mallery, Susan R.; Holpuch, Andrew S.; Phelps, Maynard P.; Schwendeman, Steven P.

    2012-01-01

    The objective of this study was to enhance oral mucosal permeation of fenretinide by co-incorporation of propylene glycol (PG) and menthol in fenretinide/Eudragit® RL PO mucoadhesive patches. Fenretinide is an extremely hydrophobic chemopreventive compound with poor tissue permeability. Co-incorporation of 5-10 wt% PG (mean Js = 16-23 μg cm−2 h−1; 158-171 μg fenretinide/g tissue) or 1-10 wt% PG + 5 wt% menthol (mean Js = 18-40 μg cm−2 h−1; 172-241 μg fenretinide/g tissue) in fenretinide/Eudragit® RL PO patches led to significant ex vivo fenretinide permeation enhancement (p < 0.001). Addition of PG above 2.5 wt% in the patch resulted in significant cellular swelling in the buccal mucosal tissues. These alterations were ameliorated by combining both enhancers and reducing PG level. After buccal administration of patches in rabbits, in vivo permeation of fenretinide across the oral mucosa was greater (~43 μg fenretinide/g tissue) from patches that contained optimized permeation enhancer content (2.5 wt% PG + 5 wt% menthol) relative to permeation obtained from enhancer-free patch (~ 17 μg fenretinide/g tissue) (p < 0.001). In vitro and in vivo release of fenretinide from patch was not significantly increased by co-incorporation of permeation enhancers, indicating that mass transfer across the tissue, and not the patch, largely determined the permeation rate control in vivo. As a result of its improved permeation and its lack of deleterious local effects, the mucoadhesive fenretinide patch co-incorporated with 2.5 wt% PG + 5 wt% menthol represents an important step in the further preclinical evaluation of oral site-specific chemoprevention strategies with fenretinide. PMID:22280430

  12. Mucoadhesive fenretinide patches for site-specific chemoprevention of oral cancer: enhancement of oral mucosal permeation of fenretinide by coincorporation of propylene glycol and menthol.

    PubMed

    Wu, Xiao; Desai, Kashappa-Goud H; Mallery, Susan R; Holpuch, Andrew S; Phelps, Maynard P; Schwendeman, Steven P

    2012-04-02

    The objective of this study was to enhance oral mucosal permeation of fenretinide by coincorporation of propylene glycol (PG) and menthol in fenretinide/Eudragit RL PO mucoadhesive patches. Fenretinide is an extremely hydrophobic chemopreventive compound with poor tissue permeability. Coincorporation of 5-10 wt % PG (mean J(s) = 16-23 μg cm⁻² h⁻¹; 158-171 μg of fenretinide/g of tissue) or 1-10 wt % PG + 5 wt % menthol (mean J(s) = 18-40 μg cm⁻² h⁻¹; 172-241 μg of fenretinide/g of tissue) in fenretinide/Eudragit RL PO patches led to significant ex vivo fenretinide permeation enhancement (p < 0.001). Addition of PG above 2.5 wt % in the patch resulted in significant cellular swelling in the buccal mucosal tissues. These alterations were ameliorated by combining both enhancers and reducing PG level. After buccal administration of patches in rabbits, in vivo permeation of fenretinide across the oral mucosa was greater (∼43 μg fenretinide/g tissue) from patches that contained optimized permeation enhancer content (2.5 wt % PG + 5 wt % menthol) relative to permeation obtained from enhancer-free patch (∼17 μg fenretinide/g tissue) (p < 0.001). In vitro and in vivo release of fenretinide from patch was not significantly increased by coincorporation of permeation enhancers, indicating that mass transfer across the tissue, and not the patch, largely determined the permeation rate control in vivo. As a result of its improved permeation and its lack of deleterious local effects, the mucoadhesive fenretinide patch coincorporated with 2.5 wt % PG + 5 wt % menthol represents an important step in the further preclinical evaluation of oral site-specific chemoprevention strategies with fenretinide.

  13. Anti-tumour necrosis factor therapy enhances mucosal healing through down-regulation of interleukin-21 expression and T helper type 17 cell infiltration in Crohn's disease.

    PubMed

    Liu, C; Xia, X; Wu, W; Wu, R; Tang, M; Chen, T; Xu, F; Cong, Y; Xu, X; Liu, Z

    2013-07-01

    Anti-tumour necrosis factor (TNF) monoclonal antibody (mAb) (infliximab, IFX) has been shown to be highly effective in the management of Crohn's disease (CD). Herein we investigated the potential role of IFX in inducing clinical remission and regulating interleukin (IL)-21 expression and T helper type 17 (Th17) cell infiltration in the intestinal mucosa of CD patients. Twenty-six CD patients were treated with IFX at weeks 0, 2 and 6. Clinical response, mucosal healing, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were evaluated at week 10 after IFX administration. Expression of IL-21, IL-17A and retinoic acid-related orphan receptor C (RORC) in intestinal mucosa were analysed by quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Peripheral blood and lamina propria CD4(+) T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of IFX. Cytokine profiles and RORC were determined with enzyme-linked immunosorbent assay (ELISA) and real-time PCR. IL-21 and Th17 cells were found to be expressed highly in inflamed mucosa of active CD patients compared with healthy controls. Ten weeks after IFX infusion, CD activity index, ESR, CRP and intestinal mucosal healing were improved markedly in CD patients, and IL-21 expression and Th17 cell infiltration were decreased significantly compared with those before IFX therapy. In-vitro study demonstrated that IFX treatment could suppress IL-21, IL-17A and RORC expression in cultured CD biopsies. Moreover, IFX was also observed to down-regulate markedly IL-17A, IL-21 and RORC expression by CD CD4(+) T cells. IFX is highly effective in inducing clinical remission and promoting intestinal mucosal healing in CD patients through down-regulation of IL-21 expression and Th17 cell infiltration in intestinal mucosa. © 2013 British Society for Immunology.

  14. Lactobacillus plantarum Strains Can Enhance Human Mucosal and Systemic Immunity and Prevent Non-steroidal Anti-inflammatory Drug Induced Reduction in T Regulatory Cells.

    PubMed

    de Vos, Paul; Mujagic, Zlatan; de Haan, Bart J; Siezen, Roland J; Bron, Peter A; Meijerink, Marjolein; Wells, Jerry M; Masclee, Ad A M; Boekschoten, Mark V; Faas, Marijke M; Troost, Freddy J

    2017-01-01

    Orally ingested bacteria interact with intestinal mucosa and may impact immunity. However, insights in mechanisms involved are limited. In this randomized placebo-controlled cross-over trial, healthy human subjects were given Lactobacillus plantarum supplementation (strain TIFN101, CIP104448, or WCFS1) or placebo for 7 days. To determine whether L. plantarum can enhance immune response, we compared the effects of three stains on systemic and gut mucosal immunity, by among others assessing memory responses against tetanus toxoid (TT)-antigen, and mucosal gene transcription, in human volunteers during induction of mild immune stressor in the intestine, by giving a commonly used enteropathic drug, indomethacin [non-steroidal anti-inflammatory drug (NSAID)]. Systemic effects of the interventions were studies in peripheral blood samples. NSAID was found to induce a reduction in serum CD4(+)/Foxp3 regulatory cells, which was prevented by L. plantarum TIFN101. T-cell polarization experiments showed L. plantarum TIFN101 to enhance responses against TT-antigen, which indicates stimulation of memory responses by this strain. Cell extracts of the specific L. plantarum strains provoked responses after WCFS1 and TIFN101 consumption, indicating stimulation of immune responses against the specific bacteria. Mucosal immunomodulatory effects were studied in duodenal biopsies. In small intestinal mucosa, TIFN101 upregulated genes associated with maintenance of T- and B-cell function and antigen presentation. Furthermore, L. plantarum TIFN101 and WCFS1 downregulated immunological pathways involved in antigen presentation and shared downregulation of snoRNAs, which may suggest cellular destabilization, but may also be an indicator of tissue repair. Full sequencing of the L. plantarum strains revealed possible gene clusters that might be responsible for the differential biological effects of the bacteria on host immunity. In conclusion, the impact of oral consumption L. plantarum on

  15. Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

    DTIC Science & Technology

    2005-03-15

    histopathological changes in every organ including the lung nd the CNS of the mice during the vaccination and during 57 days of the study. In the nasal passages of...the nasal passages are the major por- als of entry for air-borne microorganisms and bioterrorism gents, including ricin toxin, therefore, the mucosal...lung and the CNS of the mice during the vaccination and during 57 days of the study. In the nasal passages of the mice in the absence of DGCA, LTR72

  16. Reaction enhancement of point sources due to vortex stirring.

    PubMed

    Crimaldi, John P; Hartford, Jillian R; Weiss, Jeffrey B

    2006-07-01

    We investigate a class of reactive advection-diffusion problems motivated by an ecological mixing process. We use analytical and numerical methods to determine reaction rates between two initially distinct scalar point masses that are separated from one another by a third (nonreactive) scalar. The scalars are stirred by a single two-dimensional vortex in a variety of geometrical configurations. We show that the aggregate second-order reaction rate in the low-concentration limit is enhanced by the instantaneous stirring processes, relative to the rate predicted by an equivalent eddy diffusivity. The peak reaction rate grows as P(1/3), and the time to reach the peak decreases as P(-2/3), where P is the Péclet number. The results of this study have important implications not only for ecological modeling, but for the general understanding of turbulent reactive flows.

  17. Hochuekkito, a Kampo (traditional Japanese herbal) Medicine, Enhances Mucosal IgA Antibody Response in Mice Immunized with Antigen-entrapped Biodegradable Microparticles.

    PubMed

    Matsumoto, Tsukasa; Noguchi, Masaaki; Hayashi, Osamu; Makino, Kimiko; Yamada, Haruki

    2010-03-01

    The effect of oral administration of Hochuekkito (HET; Bu-Zhong-Yi-Qi-Tang in Chinese), a traditional Japanese herbal medicine, on mucosal IgA immune response was investigated. To induce the antigen-specific antibodies in mucosal site, ovalbumin (OVA)-entrapped biodegradable microparticles (OVA-microparticles) were used as an antigen. Mice were orally immunized with OVA-microparticles for 3 successive days with intragastric gavage. From 7 days after the onset of immunization, the mice were boosted twice a week with the same antigen for 2 weeks. HET or water alone was orally administered to the mice via the intragastric route from 7 days before to 27 days after the onset of immunization. Although no significant change in total secretory IgA antibody level was observed in intestinal and nasal washes, OVA-specific IgA titers in intestinal washes were significantly enhanced by oral administration of HET. When lymphocytes from spleen, peripheral blood and Payer's patches were investigated for cytokines production, it was found that the IFN-γ secretion from the lymphocytes was increased by the administration of HET. Microarray analysis of Peyer's patch cells revealed enhanced expression of L-selectin gene. The increase of L-selectin positive cells in B lymphocytes fraction was observed in Peyer's patch cells and peripheral blood mononuclear cells by flow cytometry. These results suggest that the enhanced IFN-γ secretion and increased population of L-selectin positive B lymphocytes by orally administered HET may partly contribute to enhancement of IgA immune response against intestinal antigens, and orally administered HET may strengthen defensive systems against various pathogens and food antigens in intestine.

  18. Reaction enhancement of initially distant scalars by Lagrangian coherent structures

    NASA Astrophysics Data System (ADS)

    Pratt, Kenneth R.; Meiss, James D.; Crimaldi, John P.

    2015-03-01

    Turbulent fluid flows have long been recognized as a superior means of diluting initial concentrations of scalars due to rapid stirring. Conversely, experiments have shown that the structures responsible for this rapid dilution can also aggregate initially distant reactive scalars and thereby greatly enhance reaction rates. Indeed, chaotic flows not only enhance dilution by shearing and stretching but also organize initially distant scalars along transiently attracting regions in the flow. To show the robustness of this phenomenon, a hierarchical set of three numerical flows is used: the periodic wake downstream of a stationary cylinder, a chaotic double gyre flow, and a chaotic, aperiodic flow consisting of interacting Taylor vortices. We demonstrate that Lagrangian coherent structures (LCS), as identified by ridges in finite time Lyapunov exponents, are directly responsible for this coalescence of reactive scalar filaments. When highly concentrated filaments coalesce, reaction rates can be orders of magnitude greater than would be predicted in a well-mixed system. This is further supported by an idealized, analytical model that was developed to quantify the competing effects of scalar dilution and coalescence. Chaotic flows, known for their ability to efficiently dilute scalars, therefore have the competing effect of organizing initially distant scalars along the LCS at timescales shorter than that required for dilution, resulting in reaction enhancement.

  19. Reaction enhancement of initially distant scalars by Lagrangian coherent structures

    SciTech Connect

    Pratt, Kenneth R. Crimaldi, John P.; Meiss, James D.

    2015-03-15

    Turbulent fluid flows have long been recognized as a superior means of diluting initial concentrations of scalars due to rapid stirring. Conversely, experiments have shown that the structures responsible for this rapid dilution can also aggregate initially distant reactive scalars and thereby greatly enhance reaction rates. Indeed, chaotic flows not only enhance dilution by shearing and stretching but also organize initially distant scalars along transiently attracting regions in the flow. To show the robustness of this phenomenon, a hierarchical set of three numerical flows is used: the periodic wake downstream of a stationary cylinder, a chaotic double gyre flow, and a chaotic, aperiodic flow consisting of interacting Taylor vortices. We demonstrate that Lagrangian coherent structures (LCS), as identified by ridges in finite time Lyapunov exponents, are directly responsible for this coalescence of reactive scalar filaments. When highly concentrated filaments coalesce, reaction rates can be orders of magnitude greater than would be predicted in a well-mixed system. This is further supported by an idealized, analytical model that was developed to quantify the competing effects of scalar dilution and coalescence. Chaotic flows, known for their ability to efficiently dilute scalars, therefore have the competing effect of organizing initially distant scalars along the LCS at timescales shorter than that required for dilution, resulting in reaction enhancement.

  20. Enhancement of Antituberculosis Immunity in a Humanized Model System by a Novel Virus-Vectored Respiratory Mucosal Vaccine.

    PubMed

    Yao, Yushi; Lai, Rocky; Afkhami, Sam; Haddadi, Siamak; Zganiacz, Anna; Vahedi, Fatemeh; Ashkar, Ali A; Kaushic, Charu; Jeyanathan, Mangalakumari; Xing, Zhou

    2017-07-01

    The translation of preclinically promising novel tuberculosis vaccines to ultimate human applications has been challenged by the lack of animal models with an immune system equivalent to the human immune system in its genetic diversity and level of susceptibility to tuberculosis. We have developed a humanized mice (Hu-mice) tuberculosis model system to investigate the clinical relevance of a novel virus-vectored (VV) tuberculosis vaccine administered via respiratory mucosal or parenteral route. We find that VV vaccine activates T cells in Hu-mice as it does in human vaccinees. The respiratory mucosal route for delivery of VV vaccine in Hu-mice, but not the parenteral route, significantly reduces the humanlike lung tuberculosis outcomes in a human T-cell-dependent manner. Our results suggest that the Hu-mouse can be used to predict the protective efficacy of novel tuberculosis vaccines/strategies before they proceed to large, expensive human trials. This new vaccine testing system will facilitate the global pace of clinical tuberculosis vaccine development.

  1. Enhancement of serum and mucosal immune responses to a Haemophilus influenzae Type B vaccine by intranasal delivery.

    PubMed

    Fernandez, Stefan; Cisney, Emily D; Ulrich, Robert G

    2013-11-01

    Intranasal (i.n.) vaccination is potentially the most direct method for conveying upper respiratory and mucosal immunity to respiratory pathogens. However, for unclear reasons, vaccines introduced into the nasal sinuses often have lower efficacy than vaccines administered by the more frequently used parenteral routes. We examined i.n. vaccination in a mouse immune-response model with a commonly used Haemophilus influenzae type B vaccine (Hibv) composed of the polyribosylribitol phosphate (PRP) capsule antigen conjugated to tetanus toxoid. Intranasal vaccination with Hibv using a Toll-like receptor 4 (TLR4) agonist as an adjuvant significantly increased the levels of IgA specific for the PRP capsule antigen in blood serum, saliva, and mucosal secretion specimens. In contrast, control mice vaccinated transdermally (t.d.) with Hibv did not produce significant levels of PRP-specific IgA in the blood serum and saliva, and anti-PRP IgG was increased only in serum. The i.n. and t.d. vaccinations resulted in equivalent bactericidal antibody responses in blood serum, suggesting that vaccine-derived IgG is protective against infection. Elevated levels of IgG specific for the tetanus toxoid carrier protein were measured in nasal sinuses and vaginal secretions in mice vaccinated by either the t.d. or i.n. route. Tissue culture studies confirmed that the nasopharynx-associated lymphoid tissue (NALT) was at least one of the sources of PRP-specific IgA and carrier-specific IgG within the nasal sinuses. We conclude that i.n. vaccination aided by a TLR4 agonist results in robust immune responses to both the carrier protein and bacterial polysaccharide components of the Hibv.

  2. Enhancement of thermonuclear reaction rates in extremely dense stellar plasmas

    NASA Astrophysics Data System (ADS)

    Itoh, Naoki; Kuwashima, Fumiyoshi; Munakata, Hiroharu

    1990-10-01

    The enhancement factor of the thermonuclear reaction rates is calculated for the extremely dense stellar plasmas in the liquid phase where the condition 3Gamma/tau less than or equal to 1.6 is not necessarily imposed. Here the parameter 3Gamma/tau corresponds to the ratio of the classical turning point radius at the Gamow peak and the mean interionic distance in the case of the pure Coulomb potential. Direct double integration is carried out to obtain the thermonuclear reaction rates. The result is presented in the form of an analytic fitting formula to facilitate applications. The present fitting formula is valid for 3Gamma/tau = 0-5.4. The present calculation is intended to serve as the best available one for the case that ions are in the semiquantum regime.

  3. Hepatocyte Growth Factor Mediates Enhanced Wound Healing Responses and Resistance to Transforming Growth Factor-β₁-Driven Myofibroblast Differentiation in Oral Mucosal Fibroblasts.

    PubMed

    Dally, Jordanna; Khan, Jabur S; Voisey, Alex; Charalambous, Chrisandrea; John, Hannah L; Woods, Emma L; Steadman, Robert; Moseley, Ryan; Midgley, Adam C

    2017-08-24

    Oral mucosal wounds are characterized by rapid healing with minimal scarring, partly attributable to the "enhanced" wound healing properties of oral mucosal fibroblasts (OMFs). Hepatocyte growth factor (HGF) is a pleiotropic growth factor, with potential key roles in accelerating healing and preventing fibrosis. HGF can exist as full-length or truncated (HGF-NK), NK1 and NK2 isoforms. As OMFs display elevated HGF expression compared to dermal fibroblasts (DFs), this study investigated the extent to which HGF mediates the preferential cellular functions of OMFs, and the influence of pro-fibrotic, transforming growth factor-β₁ (TGF-β₁) on these responses. Knockdown of HGF expression in OMFs by short-interfering RNA (siHGF) significantly inhibited OMF proliferative and migratory responses. Supplementation with exogenous TGF-β₁ also significantly inhibited proliferation and migration, concomitant with significantly down-regulated HGF expression. In addition, knockdown abrogated OMF resistance to TGF-β₁-driven myofibroblast differentiation, as evidenced by increased α-smooth muscle actin (α-SMA) expression, F-actin reorganisation, and stress fibre formation. Responses were unaffected in siHGF-transfected DFs. OMFs expressed significantly higher full-length HGF and NK1 levels compared to patient-matched DFs, whilst NK2 expression was similar in both OMFs and DFs. Furthermore, NK2 was preferentially expressed over NK1 in DFs. TGF-β₁ supplementation significantly down-regulated full-length HGF and NK1 expression by OMFs, while NK2 was less affected. This study demonstrates the importance of HGF in mediating "enhanced" OMF cellular function. We also propose that full-length HGF and HGF-NK1 convey desirable wound healing properties, whilst fibroblasts preferentially expressing more HGF-NK2 readily undergo TGF-β₁-driven differentiation into myofibroblasts.

  4. Enhanced Diffusion of Enzymes that Catalyze Exothermic Reactions

    NASA Astrophysics Data System (ADS)

    Golestanian, Ramin

    2015-09-01

    Enzymes have been recently found to exhibit enhanced diffusion due to their catalytic activities. A recent experiment [C. Riedel et al., Nature (London) 517, 227 (2015)] has found evidence that suggests this phenomenon might be controlled by the degree of exothermicity of the catalytic reaction involved. Four mechanisms that can lead to this effect, namely, self-thermophoresis, boost in kinetic energy, stochastic swimming, and collective heating are critically discussed, and it is shown that only the last two can be strong enough to account for the observations. The resulting quantitative description is used to examine the biological significance of the effect.

  5. Enhanced Diffusion of Enzymes that Catalyze Exothermic Reactions.

    PubMed

    Golestanian, Ramin

    2015-09-04

    Enzymes have been recently found to exhibit enhanced diffusion due to their catalytic activities. A recent experiment [C. Riedel et al., Nature (London) 517, 227 (2015)] has found evidence that suggests this phenomenon might be controlled by the degree of exothermicity of the catalytic reaction involved. Four mechanisms that can lead to this effect, namely, self-thermophoresis, boost in kinetic energy, stochastic swimming, and collective heating are critically discussed, and it is shown that only the last two can be strong enough to account for the observations. The resulting quantitative description is used to examine the biological significance of the effect.

  6. Sorption enhanced reaction process (SERP) for production of hydrogen

    SciTech Connect

    Sircar, S.; Anand, M.; Carvill, B.

    1995-09-01

    Sorption Enhanced Reaction (SER) is a novel process that is being developed for the production of lower cost hydrogen by steam-methane reforming (SMR). In this process, the reaction of methane with steam is carried out in the presence of an admixture of a catalyst and a selective adsorbent for carbon dioxide. The consequences of SER are: (1) reformation reaction at a significantly lower temperature (300-500{degrees}C) than conventional SMR (800-1100{degrees}C), while achieving the same conversion of methane to hydrogen, (2) the product hydrogen is obtained at reactor pressure (200-400 psig) and at 99+% purity directly from the reactor (compared to only 70-75% H{sub 2} from conventional SMR reactor), (3) downstream hydrogen purification step is either eliminated or significantly reduced in size. The early focus of the program will be on the identification of an adsorbent/chemisorbent for CO{sub 2} and on the demonstration of the SER concept for SMR in our state-of-the-art bench scale process. In the latter stages, a pilot plant will be built to scale-up the technology and to develop engineering data. The program has just been initiated and no significant results for SMR will be reported. However, results demonstrating the basic principles and process schemes of SER technology will be presented for reverse water gas shift reaction as the model reaction. If successful, this technology will be commercialized by Air Products and Chemicals, Inc. (APCI) and used in its existing hydrogen business. APCI is the world leader in merchant hydrogen production for a wide range of industrial applications.

  7. Enhanced reaction rates in NDP analysis with neutron scattering

    SciTech Connect

    Downing, R. Gregory

    2014-04-15

    Neutron depth profiling (NDP) makes accessible quantitative information on a few isotopic concentration profiles ranging from the surface into the sample a few micrometers. Because the candidate analytes for NDP are few, there is little interference encountered. Furthermore, neutrons have no charge so mixed chemical states in the sample are of no direct concern. There are a few nuclides that exhibit large probabilities for neutron scattering. The effect of neutron scattering on NDP measurements has not previously been evaluated as a basis for either enhancing the reaction rates or as a source of measurement error. Hydrogen is a common element exhibiting large neutron scattering probability found in or around sample volumes being analyzed by NDP. A systematic study was conducted to determine the degree of signal change when neutron scattering occurs during analysis. The relative signal perturbation was evaluated for materials of varied neutron scattering probability, concentration, total mass, and geometry. Signal enhancements up to 50% are observed when the hydrogen density is high and in close proximity to the region of analysis with neutron beams of sub thermal energies. Greater signal enhancements for the same neutron number density are reported for thermal neutron beams. Even adhesive tape used to position the sample produces a measureable signal enhancement. Because of the shallow volume, negligible distortion of the NDP measured profile shape is encountered from neutron scattering.

  8. Enhanced reaction rates in NDP analysis with neutron scattering

    NASA Astrophysics Data System (ADS)

    Downing, R. Gregory

    2014-04-01

    Neutron depth profiling (NDP) makes accessible quantitative information on a few isotopic concentration profiles ranging from the surface into the sample a few micrometers. Because the candidate analytes for NDP are few, there is little interference encountered. Furthermore, neutrons have no charge so mixed chemical states in the sample are of no direct concern. There are a few nuclides that exhibit large probabilities for neutron scattering. The effect of neutron scattering on NDP measurements has not previously been evaluated as a basis for either enhancing the reaction rates or as a source of measurement error. Hydrogen is a common element exhibiting large neutron scattering probability found in or around sample volumes being analyzed by NDP. A systematic study was conducted to determine the degree of signal change when neutron scattering occurs during analysis. The relative signal perturbation was evaluated for materials of varied neutron scattering probability, concentration, total mass, and geometry. Signal enhancements up to 50% are observed when the hydrogen density is high and in close proximity to the region of analysis with neutron beams of sub thermal energies. Greater signal enhancements for the same neutron number density are reported for thermal neutron beams. Even adhesive tape used to position the sample produces a measureable signal enhancement. Because of the shallow volume, negligible distortion of the NDP measured profile shape is encountered from neutron scattering.

  9. Enhanced reaction rates in NDP analysis with neutron scattering.

    PubMed

    Downing, R Gregory

    2014-04-01

    Neutron depth profiling (NDP) makes accessible quantitative information on a few isotopic concentration profiles ranging from the surface into the sample a few micrometers. Because the candidate analytes for NDP are few, there is little interference encountered. Furthermore, neutrons have no charge so mixed chemical states in the sample are of no direct concern. There are a few nuclides that exhibit large probabilities for neutron scattering. The effect of neutron scattering on NDP measurements has not previously been evaluated as a basis for either enhancing the reaction rates or as a source of measurement error. Hydrogen is a common element exhibiting large neutron scattering probability found in or around sample volumes being analyzed by NDP. A systematic study was conducted to determine the degree of signal change when neutron scattering occurs during analysis. The relative signal perturbation was evaluated for materials of varied neutron scattering probability, concentration, total mass, and geometry. Signal enhancements up to 50% are observed when the hydrogen density is high and in close proximity to the region of analysis with neutron beams of sub thermal energies. Greater signal enhancements for the same neutron number density are reported for thermal neutron beams. Even adhesive tape used to position the sample produces a measureable signal enhancement. Because of the shallow volume, negligible distortion of the NDP measured profile shape is encountered from neutron scattering.

  10. [Mucosal immune system and mucosal vaccine].

    PubMed

    Yanagita, M; Hiroi, T; Kiyono, H

    1997-02-01

    In the recent years, mucosal immune system is recognized as the new world in the area of immunology. The host is continuously exposed to the numerous numbers of environmental antigens via the mucosa and the skin. A total surface area of the mucosa is approximately 200 times larger than that of the skin, and the former surface area contains a large numbers of lymphoid cells (> 10(11)). In order to provide an effective defence for the host by vaccine, it is logical to consider the mucosal immune system. According to the new informations obtained by the modern cellular and molecular immunobiological knowledges and approaches, the concept of the mucosal immune system has been rapidly proceeded to apply for the development of mucosal vaccine. In this report, we have reviewed and discussed the recent progress in the characterization of mucosal immune system and the development of mucosal vaccine.

  11. Enhanced Light Scattering of Secondary Organic Aerosols by Multiphase Reactions.

    PubMed

    Li, Kun; Li, Junling; Liggio, John; Wang, Weigang; Ge, Maofa; Liu, Qifan; Guo, Yucong; Tong, Shengrui; Li, Jiangjun; Peng, Chao; Jing, Bo; Wang, Dong; Fu, Pingqing

    2017-02-07

    Secondary organic aerosol (SOA) plays a pivotal role in visibility and radiative forcing, both of which are intrinsically linked to the refractive index (RI). While previous studies have focused on the RI of SOA from traditional formation processes, the effect of multiphase reactions on the RI has not been considered. Here, we investigate the effects of multiphase processes on the RI and light-extinction of m-xylene-derived SOA, a common type of anthropogenic SOA. We find that multiphase reactions in the presence of liquid water lead to the formation of oligomers from intermediate products such as glyoxal and methylglyoxal, resulting in a large enhancement in the RI and light-scattering of this SOA. These reactions will result in increases in light-scattering efficiency and direct radiative forcing of approximately 20%-90%. These findings improve our understanding of SOA optical properties and have significant implications for evaluating the impacts of SOA on the rapid formation of regional haze, global radiative balance, and climate change.

  12. Alphavirus replicon-based enhancement of mucosal and systemic immunity is linked to the innate response generated by primary immunization

    PubMed Central

    Tonkin, Daniel R; Jorquera, Patricia; Todd, Tracie; Beard, Clayton W; Johnston, Robert E; Barro, Mario

    2010-01-01

    Venezuelan equine encephalitis virus replicon particles (VRP) function as an effective systemic, cellular and mucosal adjuvant when codelivered with antigen, and show promise for use as a component in new and existing human vaccine formulations. We show here that VRP are effective at low dose and by intramuscular delivery, two useful features for implementation of VRP as a vaccine adjuvant. In mice receiving a prime and boost with antigen, we found that VRP are required in prime only to produce a full adjuvant effect. This outcome indicates that the events triggered during prime with VRP are sufficient to establish the nature and magnitude of the immune response to a second exposure to antigen. Events induced by VRP in the draining lymph node after prime include robust secretion of many inflammatory cytokines, upregulation of CD69 on leukocytes, and increased cellularity, with a disproportionate increase of a cell population expressing CD11c, CD11b, and F4/80. We show that antigen delivered 24 hours after administration of VRP does not benefit from an adjuvant effect, indicating that the events which are critical to VRP-mediated adjuvant activity occur within the first 24 hours. Further studies of the events induced by VRP will help elucidate the mechanism of VRP adjuvant activity and will advance the safe implementation of this adjuvant in human vaccines. PMID:20184975

  13. Alphavirus replicon-based enhancement of mucosal and systemic immunity is linked to the innate response generated by primary immunization.

    PubMed

    Tonkin, Daniel R; Jorquera, Patricia; Todd, Tracie; Beard, Clayton W; Johnston, Robert E; Barro, Mario

    2010-04-19

    Venezuelan equine encephalitis virus replicon particles (VRP) function as an effective systemic, cellular and mucosal adjuvant when codelivered with antigen, and show promise for use as a component in new and existing human vaccine formulations. We show here that VRP are effective at low dose and by intramuscular delivery, two useful features for implementation of VRP as a vaccine adjuvant. In mice receiving a prime and boost with antigen, we found that VRP are required in prime only to produce a full adjuvant effect. This outcome indicates that the events triggered during prime with VRP are sufficient to establish the nature and magnitude of the immune response to a second exposure to antigen. Events induced by VRP in the draining lymph node after prime include robust secretion of many inflammatory cytokines, upregulation of CD69 on leukocytes, and increased cellularity, with a disproportionate increase of a cell population expressing CD11c, CD11b, and F4/80. We show that antigen delivered 24h after administration of VRP does not benefit from an adjuvant effect, indicating that the events which are critical to VRP-mediated adjuvant activity occur within the first 24h. Further studies of the events induced by VRP will help elucidate the mechanism of VRP adjuvant activity and will advance the safe implementation of this adjuvant in human vaccines. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. Porous platinum mesoflowers with enhanced activity for methanol oxidation reaction

    SciTech Connect

    Zhuang Lina; Wang Wenjin; Hong Feng; Yang Shengchun; You Hongjun; Fang Jixiang; Ding Bingjun

    2012-07-15

    Porous Pt and Pt-Ag alloy mesoflowers (MFs) with about 2 {mu}m in diameter and high porosity were synthesized using Ag mesoflowers as sacrificial template by galvanic reaction. The silver content in Pt-Ag alloys can be facilely controlled by nitric acid treatment. And the pure Pt MFs can be obtained by selective removal of silver element from Pt{sub 72}Ag{sub 28} MFs electrochemically. Both Pt{sub 45}Ag{sub 55}, Pt{sub 72}Ag{sub 28} and pure Pt show a high catalytic performance in methanol oxidation reaction (MOR). Especially, pure Pt MFs exhibited a 2 to 3 times current density enhancement in MOR compared with the commercial used Pt black, which can be attributed to their porous nanostructure with 3-dimentional nature and small crystal sizes. - Graphical Abstract: The CVs of MOR on Pt (red) and Pt black (green) catalysts in 0.1 M HClO{sub 4} and 0.5 M CH{sub 3}OH for specific mass current. The insert shows the SEM images of two porous Pt MFs. Platinum mesoflowers (MFs) with about 2 {mu}m in diameter and high porosity were synthesised with Ag mesoflowers as sacrificial template by galvanic replacement. The porous Pt MFs exhibited a more than 3 times enhancement in electrocatalytic performance for methanol oxidation reaction compared the commercial used Pt black. Highlights: Black-Right-Pointing-Pointer Porous Pt and Pt-Ag mesoflowers (MFs) were synthesized using Ag MFs sacrifical template. Black-Right-Pointing-Pointer Pt MFs presents an improved catalytic activity in MOR compared with Pt black. Black-Right-Pointing-Pointer We provided a facile approach for the development of high performance Pt electrocatalysts for fuel cells.

  15. Development of a novel adjuvanted nasal vaccine: C48/80 associated with chitosan nanoparticles as a path to enhance mucosal immunity.

    PubMed

    Bento, D; Staats, H F; Gonçalves, T; Borges, O

    2015-06-01

    In a time in which mucosal vaccines development has been delayed by the lack of safe and effective mucosal adjuvants, the combination of adjuvants has started to be explored as a strategy to obtain potent vaccine formulations. This study describes a novel adjuvant combination as an effective approach for a nasal vaccine - the association of the mast cell activator compound 48/80 with chitosan based nanoparticles. It was hypothesized that mucoadhesive nanoparticles would promote the cellular uptake and prolong the antigen residence time on nasal cavity. Simultaneously, mast cell activation would promote a local microenvironment favorable to the development of an immune response. To test this hypothesis, two different C48/80 loaded nanoparticles (NPs) were prepared: Chitosan-C48/80 NP (Chi-C48/80 NP) and Chitosan/Alginate-C48/80 NP (Chi/Alg-C48/80 NP). The potential as a vaccine adjuvant of the two delivery systems was evaluated and directly compared. Both formulations had a mean size near 500nm and a positive charge; however, Chi-C48/80 NP was a more effective adjuvant delivery system when compared with Chi/Alg-C48/80 NP or C48/80 alone. Chi-C48/80 NP activated mast cells at a greater extent, were better internalized by antigen presenting cells than Chi/Alg-C48/80 NP and successfully enhanced the nasal residence time of a model antigen. Superiority of Chi-C48/80 NP as adjuvant was also observed in vivo. Therefore, nasal immunization of mice with Bacillus anthracis protective antigen (PA) adsorbed on Chi-C48/80 NP elicited high levels of serum anti-PA neutralizing antibodies and a more balanced Th1/Th2 profile than C48/80 in solution or Chi/Alg-C48/80 NP. The incorporation of C48/80 within Chi NP also promoted a mucosal immunity greater than all the other adjuvanted groups tested, showing that the combination of a mast cell activator and chitosan NP could be a promising strategy for nasal immunization. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Early Mucosal Reactions During and After Head-and-Neck Radiotherapy: Dependence of Treatment Tolerance on Radiation Dose and Schedule Duration

    SciTech Connect

    Fenwick, John D. Lawrence, Geoff P.; Malik, Zafar; Nahum, Alan E.; Mayles, W. Philip M.

    2008-06-01

    Purpose: To more precisely localize the dose-time boundary between head-and-neck radiotherapy schedules inducing tolerable and intolerable early mucosal reactions. Methods and Materials: Total cell-kill biologically effective doses (BED{sub CK}) have been calculated for 84 schedules, including incomplete repair effects, but making no other corrections for the effect of schedule duration T. [BED{sub CK},T] scatterplots are graphed, overlying BED{sub CKboundary}(T) curves on the plots and using discriminant analysis to optimize BED{sub CKboundary}(T) to best represent the boundary between the tolerable and intolerable schedules. Results: More overlap than expected is seen between the tolerable and intolerable treatments in the 84-schedule [BED{sub CK},T] scatterplot, but this was largely eliminated by removing gap and tolerated accelerating schedules from the plot. For the remaining 57 predominantly regular schedules, the BED{sub CKboundary}(T) boundary increases with increasing T (p = 0.0001), curving upwards significantly nonlinearly (p = 0.00007) and continuing to curve beyond 15 days (p = 0.035). The regular schedule BED{sub CKboundary}(T) boundary does not describe tolerability well for accelerating schedules (p = 0.002), with several tolerated accelerating schedules lying above the boundary where regular schedules would be intolerable. Gap schedule tolerability also is not adequately described by the regular schedule boundary (p = 0.04), although no systematic offset exists between the regular boundary and the overall gap schedule tolerability pattern. Conclusions: All schedules analyzed (regular, gap, and accelerating) with BED{sub CK} values below BED{sub CKboundary}(T)=69.5x(T/32.2)/sin((T/32.2){sup (radians)})-3.5Gy= {sub 10}(forT{<=}50 days) are tolerable, and many lying above the boundary are intolerable. The accelerating schedules analyzed were tolerated better overall than are the regular schedules with similar [BED{sub CK},T] values.

  17. Computerized approaches to enhance understanding of organic reaction mechanisms: CAN reaction mechanisms and CPLEX prelaboratory methodology

    NASA Astrophysics Data System (ADS)

    Al-Shammari, Abdulrahman G. Alhamzani

    2008-10-01

    Two approaches to enhance the understanding of organic reaction mechanisms are described. First, a new method for teaching organic reaction mechanisms that can be used in a Computer-Assisted Instruction (CAI) environment is proposed and tested (Chapter 1). The method concentrates upon the important intermediate structures, which are assumed to be on the reaction coordinate, and which can be evaluated and graded by currently available computer techniques. At the same time, the "curved arrows" that show the electron flow in a reaction mechanism are neglected, since they cannot be evaluated and graded with currently available computer techniques. By allowing student practice for learning organic reaction mechanisms using the Curved Arrow Neglect (CAN) method within a "Practice Makes Perfect" CAI method, student performance in the drawing of traditional reaction mechanisms, in which students had to include the "curved arrows" on their written classroom exams, was significantly enhanced. Second, computerized prelaboratory experiments (CPLEX) for organic chemistry laboratory 1 & 2 courses have been created, used, and evaluated (Chapters 2 and 3). These computerized prelabs are unique because they combine both "dry lab" actions with detailed animations of the actual chemistry occurring at the molecular level. The "dry lab" serves to simulate the actual physical manipulations of equipment and chemicals that occur in the laboratory experiment through the use of drag-and-drop computer technology. At the same time, these physical actions are accompanied on a separate part of the computer screen by animations showing the chemistry at the molecular level that is occurring in the experiment. These CPLEX modules were made into Internet accessible modules. The students were allowed to access the CPLEX modules prior to performing the actual laboratory experiment. A detailed evaluation of students' perception of the modules was accomplished via survey methodology during the entire

  18. Biology of HIV Mucosal Transmission

    PubMed Central

    Wu, Li

    2008-01-01

    Purpose of review HIV-1 mucosal transmission plays a critical role in HIV-1 infection and AIDS pathogenesis. This review summarizes the latest advances in biological studies of HIV-1 mucosal transmission, highlighting the implications of these studies in the development of microbicides to prevent HIV-1 transmission. Recent findings New studies of initial HIV-1 infection using improved culture models updated the current view of mucosal transmission. Mechanistic studies enhanced our understanding of cell-cell transmission of HIV-1 mediated by the major target cells, including dendritic cells, CD4+ T cells, and macrophages. Increasing evidence indicated the significance of host factors and immune responses in HIV-1 mucosal infection and transmission. Summary Recent progress in HIV-1 mucosal infection and transmission enriches our knowledge of virus-host interactions and viral pathogenesis. Functional studies of HIV-1 interactions with host cells can provide new insights into the design of more effective approaches to combat HIV-1 infection and AIDS. PMID:18802490

  19. Multifunctional polyurethane sponge for polymerase chain reaction enhancement.

    PubMed

    Seok, Seunghwan; Shin, Sujeong; Lee, Tae Jae; Jeong, Jae-Min; Yang, MinHo; Kim, Do Hyun; Park, Jung Youn; Lee, Seok Jae; Choi, Bong Gill; Lee, Kyoung G

    2015-03-04

    Selective filtering of target biomaterials from impurities is an important task in DNA amplification through polymerase chain reaction (PCR) enhancement and gene identification to save endangered animals and marine species. Conventional gene extraction methods require complicated steps, skilled persons, and expensive chemicals and instruments to improve DNA amplification. Herein, we proposed an alternative method for overcoming such challenges by imparting secondary functionality using commercially available polyurethane (PU) sponges and cost-effective fabrication approaches through polydopamine and polysiloxane coatings. The porous, highly flexible, and chemically modified superhydrophilic and superhydrophobic PU sponges allow large surface areas and mechanically stable frames for effective extraction of genomic DNA through selective filtering of fish tissues and oils. Furthermore, these chemically modified PU sponges allow separation of genes and improvement of PCR for DNA amplification for the identification of fish species. The combination of a simple fabrication method and functionalized PU sponges could be a useful platform for PCR enhancement and gene-based identification of species for practical applications.

  20. Sorption enhanced reaction process (SERP) for the production of hydrogen

    SciTech Connect

    Hufton, J.; Mayorga, S.; Gaffney, T.; Nataraj, S.; Rao, M.; Sircar, S.

    1998-08-01

    The novel Sorption Enhanced Reaction Process has the potential to decrease the cost of hydrogen production by steam methane reforming. Current effort for development of this technology has focused on adsorbent development, experimental process concept testing, and process development and design. A preferred CO{sub 2} adsorbent, K{sub 2}CO{sub 3} promoted hydrotalcite, satisfies all of the performance targets and it has been scaled up for process testing. A separate class of adsorbents has been identified which could potentially improve the performance of the H{sub 2}-SER process. Although this material exhibits improved CO{sub 2} adsorption capacity compared to the HTC adsorbent, its hydrothermal stability must be improved. Single-step process experiments (not cyclic) indicate that the H{sub 2}-SER reactor performance during the reaction step improves with decreasing pressure and increasing temperature and steam to methane ratio in the feed. Methane conversion in the H{sub 2}-SER reactor is higher than for a conventional catalyst-only reactor operated at similar temperature and pressure. The reactor effluent gas consists of 90+% H{sub 2}, balance CH{sub 4}, with only trace levels (< 50 ppm) of carbon oxides. A best-case process design (2.5 MMSCFD of 99.9+% H{sub 2}) based on the HTC adsorbent properties and a revised SER process cycle has been generated. Economic analysis of this design indicates the process has the potential to reduce the H{sub 2} product cost by 25--31% compared to conventional steam methane reforming.

  1. Sorption Enhanced Reaction Process (SERP) for production of hydrogen

    SciTech Connect

    Anand, M.; Hufton, J.; Mayorga, S.

    1996-10-01

    Sorption Enhanced Reaction Process (SERP) is a novel process that is being developed for the production of lower cost hydrogen by steam-methane reforming (SMR). In this process the reaction of methane with steam is carried out in the presence of an admixture of a catalyst and a selective adsorbent for carbon dioxide. The key consequences of SERP are: (i) reformation reaction is carried out at a significantly lower temperature (300-500{degrees}C) than that in a conventional SMR reactor (800-1100{degrees}C), while achieving the same conversion of methane to hydrogen, (ii) the product hydrogen is obtained at reactor pressure (200-400 psig) and at 98+% purity directly from the reactor (compared to only 70-75% H{sub 2} from conventional SMR reactor), (iii) downstream hydrogen purification step is either eliminated or significantly reduced in size. The first phase of the program has focused on the development of a sorbent for CO{sub 2} which has (a) reversible CO{sub 2} capacity >0.3 mmol/g at low partial pressures of CO{sub 2} (0.1 - 1.0 atm) in the presence of excess steam (pH{sub 2}O/pCO{sub 2}>20) at 400-500{degrees}C and (b) fast sorption-desorption kinetics for CO{sub 2}, at 400-500{degrees}C. Several families of supported sorbents have been identified that meet the target CO{sub 2} capacity. A few of these sorbents have been tested under repeated sorption/desorption cycles and extended exposure to high pressure steam at 400-500{degrees}C. One sorbent has been scaled up to larger quantities (2-3 kg) and tested in the laboratory process equipment for sorption and desorption kinetics of CO{sub 2}. The CO{sub 2}, sorption and desorption kinetics are desirably fast. This was a critical path item for the first phase of the program and now has been successfully demonstrated. A reactor has been designed that will allow nearly isothermal operation for SERP-SMR. This reactor was integrated into an overall process flow diagram for the SERP-SMR process.

  2. Depth-resolved measurement of mucosal microvascular blood content using 
low-coherence enhanced backscattering spectroscopy

    PubMed Central

    Radosevich, Andrew J.; Turzhitsky, Vladimir M.; Mutyal, Nikhil N.; Rogers, Jeremy D.; Stoyneva, Valentina; Tiwari, Ashish Kumar; De La Cruz, Mart; Kunte, Dhananjay P.; Wali, Ramesh K.; Roy, Hemant K.; Backman, Vadim

    2010-01-01

    Low-coherence enhanced backscattering (LEBS) spectroscopy is a light scattering technique which uses partial spatial coherence broadband illumination to interrogate the optical properties at sub-diffusion length scales. In this work, we present a post-processing technique which isolates the hemoglobin concentration at different depths within a sample using a single spectroscopic LEBS measurement with a fixed spatial coherence of illumination. We verify the method with scattering (spectralon reflectance standard and polystyrene microspheres) and absorbing (hemoglobin) phantoms. We then demonstrate the relevance of this method for quantifying hemoglobin content as a function of depth within biological tissue using the azoxymethane treated animal model of colorectal cancer. PMID:21258541

  3. Depth-resolved measurement of mucosal microvascular blood content using 
low-coherence enhanced backscattering spectroscopy.

    PubMed

    Radosevich, Andrew J; Turzhitsky, Vladimir M; Mutyal, Nikhil N; Rogers, Jeremy D; Stoyneva, Valentina; Tiwari, Ashish Kumar; De La Cruz, Mart; Kunte, Dhananjay P; Wali, Ramesh K; Roy, Hemant K; Backman, Vadim

    2010-10-20

    Low-coherence enhanced backscattering (LEBS) spectroscopy is a light scattering technique which uses partial spatial coherence broadband illumination to interrogate the optical properties at sub-diffusion length scales. In this work, we present a post-processing technique which isolates the hemoglobin concentration at different depths within a sample using a single spectroscopic LEBS measurement with a fixed spatial coherence of illumination. We verify the method with scattering (spectralon reflectance standard and polystyrene microspheres) and absorbing (hemoglobin) phantoms. We then demonstrate the relevance of this method for quantifying hemoglobin content as a function of depth within biological tissue using the azoxymethane treated animal model of colorectal cancer.

  4. Evaluation of alkylmaltosides as intestinal permeation enhancers: comparison between rat intestinal mucosal sheets and Caco-2 monolayers.

    PubMed

    Petersen, Signe Beck; Nolan, Gavin; Maher, Sam; Rahbek, Ulrik Lytt; Guldbrandt, Mette; Brayden, David J

    2012-11-20

    Alkylmaltosides are a class of non-ionic surfactant currently in clinical trials to improve nasal permeation of peptide drugs, however few studies have detailed their potential effects on intestinal permeation enhancement. Tetradecyl maltoside (TDM, C(14)), was examined in Caco-2 monolayers and in isolated rat jejunal and colonic mucosae mounted in Ussing chambers. Dodecyl maltoside (DDM, C(12)) was examined in mucosae. Parameters measured included critical micelle concentration (CMC), transepithelial electrical resistance (TEER), and apparent permeability coefficients (P(app)) of paracellular and transcellular flux markers. TDM and DDM decreased TEER and increased the P(app) of [(14)C]-mannitol and FD-4 across Caco-2 monolayers and colonic mucosae in the concentration range of 0.01-0.1% w/v, concentrations much higher than the CMC. Remarkably, neither agent had any effect on the TEER or fluxes of jejunal mucosae. Histopathology, cell death assays (MTT and LDH) and sub-lethal high content cytotoxicity analyses (HCA) were carried out with TDM. Exposure of colonic mucosae to high concentrations of TDM had no major effects on gross histology and ion transport function was retained. In Caco-2, HCA data at sub-lethal concentrations of TDM was consistent with the action of a mild non-ionic surfactant. In conclusion, alkylmaltosides are effective non-toxic permeation enhancers in isolated colonic tissue and their inclusion in oral peptide formulations directed to that intestinal region warrants further study. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Palliation of radiation-related mucositis

    SciTech Connect

    Rothwell, B.R.; Spektor, W.S.

    1990-01-01

    Oral mucositis associated with head and neck radiotherapy can substantially hinder completion of cancer therapy. Alleviation of this often severe stomatitis can provide enhanced patient comfort and facilitate appropriate care. A double-blind format was used in a pilot project to measure, against a control rinse, the effectiveness of an oral rinse consisting of hydrocortisone, nystatin, tetracycline, and diphenhydramine in controlling radiation-related mucositis. A combination of clinical evaluation and patient responses to a questionnaire was used to judge the results of the topical medications. Patients using the experimental medication developed less mucositis than did patients in the control group.

  6. Neutralisation of the interleukin-33/ST2 pathway ameliorates experimental colitis through enhancement of mucosal healing in mice

    PubMed Central

    Sedhom, Mamdouh A K; Pichery, Mélanie; Murdoch, Jenna R; Foligné, Benoit; Ortega, Nathalie; Normand, Sylvain; Mertz, Kirsten; Sanmugalingam, Devika; Brault, Lea; Grandjean, Teddy; Lefrancais, Emma; Fallon, Padraic G; Quesniaux, Valérie; Peyrin-Biroulet, Laurent; Cathomas, Gieri; Junt, Tobias; Chamaillard, Mathias; Girard, Jean-Philippe; Ryffel, Bernhard

    2013-01-01

    Objective Inflammatory bowel diseases (IBD) have been intrinsically linked to a deregulated cytokine network, but novel therapeutic principles are urgently needed. Here we identify the interleukin (IL)-33 and its receptor ST2 as key negative regulators of wound healing and permeability in the colon of mice. Design Expression of IL-33 and ST2 was determined by qRT-PCR, ELISA, immunohistochemistry and western-blot analysis. Wild-type and St2−/− mice were used in wound healing experiments and in two experimental models of IBD triggered by 2,4,6-trinitrobenzene sulphonic acid or dextran sodium sulphate (DSS). Neutralisation of ST2 was performed by using a specific blocking antibody. Results Nuclear localisation and enhanced expression of IL-33 in myofibroblasts and enterocytes was linked to disease involvement independently of inflammation, while the expression of ST2 was primarily restricted to the colonic epithelia. In two experimental models of IBD, genetic ablation of ST2 significantly improved signs of colitis, while a sustained epithelial expression of the cyto-protective factor connexin-43 was observed in DSS-treated St2-deficient mice. Unexpectedly, absence of ST2 in non-hematopoietic cells was sufficient to protect against colitis. Consistently, specific inhibition of endogenous ST2-mediated signalling by treatment with neutralising antibody improved DSS-induced colitis. In addition, IL-33 treatment impaired epithelial barrier permeability in vitro and in vivo, whereas absence of ST2 enhanced wound healing response upon acute mechanical injury in the colon. Conclusions Our study unveiled a novel non-hematopoietic function of IL-33 in epithelial barrier function and wound healing. Therefore, blocking the IL-33/ST2 axis may represent an efficient therapy in IBD. PMID:23172891

  7. Enhanced Mucosal Defense and Reduced Tumor Burden in Mice with the Compromised Negative Regulator IRAK-M.

    PubMed

    Rothschild, Daniel E; Zhang, Yao; Diao, Na; Lee, Christina K; Chen, Keqiang; Caswell, Clayton C; Slade, Daniel J; Helm, Richard F; LeRoith, Tanya; Li, Liwu; Allen, Irving C

    2017-02-01

    Aberrant inflammation is a hallmark of inflammatory bowel disease (IBD) and colorectal cancer. IRAK-M is a critical negative regulator of TLR signaling and overzealous inflammation. Here we utilize data from human studies and Irak-m(-/-) mice to elucidate the role of IRAK-M in the modulation of gastrointestinal immune system homeostasis. In human patients, IRAK-M expression is up-regulated during IBD and colorectal cancer. Further functional studies in mice revealed that Irak-m(-/-) animals are protected against colitis and colitis associated tumorigenesis. Mechanistically, our data revealed that the gastrointestinal immune system of Irak-m(-/-) mice is highly efficient at eliminating microbial translocation following epithelial barrier damage. This attenuation of pathogenesis is associated with expanded areas of gastrointestinal associated lymphoid tissue (GALT), increased neutrophil migration, and enhanced T-cell recruitment. Further evaluation of Irak-m(-/-) mice revealed a splice variant that robustly activates NF-κB signaling. Together, these data identify IRAK-M as a potential target for future therapeutic intervention.

  8. Preventative vaccine-loaded mannosylated chitosan nanoparticles intended for nasal mucosal delivery enhance immune responses and potent tumor immunity.

    PubMed

    Yao, Wenjun; Peng, Yixing; Du, Mingzhu; Luo, Juan; Zong, Li

    2013-08-05

    Chitosan (CS) has been extensively used as a protein drug and gene delivery carrier, but its delivery efficiency is unsatisfactory. In this study, a mannose ligand was used to modify CS, which could enhance the delivery efficiency of CS via mannose receptor-mediated endocytosis. A preventative anti-GRP DNA vaccine (pCR3.1-VS-HSP65-TP-GRP6-M2, pGRP) was condensed with mannosylated chitosan (MCS) to form MCS/pGRP nanoparticles. Nanoparticles were intranasally administered in a subcutaneous mice prostate carcinoma model to evaluate the efficacy on inhibition of the growth of tumor cells. The titers of anti-GRP IgG that lasted for 11 weeks were significantly higher than that for administration of CS/pGRP nanoparticles (p < 0.01) and intramuscular administration of a pGRP solution (p < 0.05) to mice. In addition, immunization with MCS/pGRP nanoparticles could suppress the growth of tumor cells. The average tumor weight (0.79 ± 0.30 g) was significantly lower than that in the CS/pGRP nanoparticle group (1.69 ± 0.15 g) (p < 0.01) or that in the pGRP group (1.12 ± 0.37 g) (p < 0.05). Cell binding and cellular uptake results indicated that MCS/pGRP nanoparticles bound with C-type lectin receptors on macrophages. MCS was an efficient targeting gene delivery carrier and could be used in antitumor immunotherapy.

  9. A study on a dental device for the prevention of mucosal dose enhancement caused by backscatter radiation from dental alloy during external beam radiotherapy

    PubMed Central

    Katsura, Kouji; Utsunomiya, Satoru; Abe, Eisuke; Sakai, Hironori; Kushima, Naotaka; Tanabe, Satoshi; Yamada, Takumi; Hayakawa, Takahide; Yamanoi, Yoshihiko; Kimura, Syuhei; Wada, Shinichi; Aoyama, Hidefumi; Hayashi, Takafumi

    2016-01-01

    The changes in dose distribution caused by backscatter radiation from a common commercial dental alloy (Au–Ag–Pd dental alloy; DA) were investigated to identify the optimal material and thicknesses of a dental device (DD) for effective prevention of mucositis. To this end, 1 cm3 of DA was irradiated with a 6-MV X-ray beam (100 MU) in a field size of 10 × 10 cm2 using a Novalis TX linear accelerator. Ethylene vinyl acetate copolymer, polyolefin elastomer, and polyethylene terephthalate (PET) were selected as DD materials. The depth dose along the central axis was determined with respect to the presence/absence of DA and DDs at thicknesses of 1–10 mm using a parallel-plate ionization chamber. The dose in the absence of DDs showed the lowest value at a distance of 5 mm from the DA surface and gradually increased with distance between the measurement point and the DA surface for distances of ≥5 mm. Except for PET, no significant difference between the DA dose curves for the presence and absence of DDs was observed. In the dose curve, PET showed a slightly higher dose for DA with DD than for DA without DD for thicknesses of ≥4 mm. The findings herein suggest that the optimal DD material for preventing local dose enhancement of the mucosa caused by DA backscatter radiation should have a relatively low atomic number and physical density and that optimal DD thickness should be chosen considering backscatter radiation and percentage depth dose. PMID:27702778

  10. A study on a dental device for the prevention of mucosal dose enhancement caused by backscatter radiation from dental alloy during external beam radiotherapy.

    PubMed

    Katsura, Kouji; Utsunomiya, Satoru; Abe, Eisuke; Sakai, Hironori; Kushima, Naotaka; Tanabe, Satoshi; Yamada, Takumi; Hayakawa, Takahide; Yamanoi, Yoshihiko; Kimura, Syuhei; Wada, Shinichi; Aoyama, Hidefumi; Hayashi, Takafumi

    2016-11-01

    The changes in dose distribution caused by backscatter radiation from a common commercial dental alloy (Au-Ag-Pd dental alloy; DA) were investigated to identify the optimal material and thicknesses of a dental device (DD) for effective prevention of mucositis. To this end, 1 cm(3) of DA was irradiated with a 6-MV X-ray beam (100 MU) in a field size of 10 × 10 cm(2) using a Novalis TX linear accelerator. Ethylene vinyl acetate copolymer, polyolefin elastomer, and polyethylene terephthalate (PET) were selected as DD materials. The depth dose along the central axis was determined with respect to the presence/absence of DA and DDs at thicknesses of 1-10 mm using a parallel-plate ionization chamber. The dose in the absence of DDs showed the lowest value at a distance of 5 mm from the DA surface and gradually increased with distance between the measurement point and the DA surface for distances of ≥5 mm. Except for PET, no significant difference between the DA dose curves for the presence and absence of DDs was observed. In the dose curve, PET showed a slightly higher dose for DA with DD than for DA without DD for thicknesses of ≥4 mm. The findings herein suggest that the optimal DD material for preventing local dose enhancement of the mucosa caused by DA backscatter radiation should have a relatively low atomic number and physical density and that optimal DD thickness should be chosen considering backscatter radiation and percentage depth dose.

  11. Gastroduodenal Mucosal Defense Mechanisms

    PubMed Central

    Said, Hyder; Kaji, Izumi; Kaunitz, Jonathan D.

    2015-01-01

    Purpose of Review To highlight recent developments in the field of gastroduodenal mucosal defense with emphasis on lumen-gut interactions. Recent Findings There has been a growing interest in the physiological functions of luminal chemosensors present from tongue to colon that detect organic molecules in the luminal content associated with nutrient ingestion, usually associated with specialized cells, in particular the enteroendocrine cells. These receptors transduce the release of peptide hormones, in particular proglucagon-derived products such as the glucagon-like-peptides (GLPs), which have profound effects on gut function and on metabolism. Luminal chemosensors transduce GLP release in response to changes in the cellular environment, as part of the mechanism of nutrient chemosensing. GLP-2 has important trophic effects on the intestinal mucosa, including increasing the proliferation rate of stem cells and reducing transmucosal permeability to ions and small molecules, in addition to increasing the rate of duodenal bicarbonate secretion. GLP-1, although traditionally considered an incretin that enhances the effect of insulin on peripheral tissues, also has trophic effects on the intestinal epithelium. Summary A better understanding of the mechanisms that mediate GLP release can further illuminate the importance of nutrient chemosensing as an important component of the mechanism that mediates the trophic effects of luminal nutrients. GLP-1 and -2 are already in clinical use for the treatment of diabetes and intestinal failure. Improved understanding of the control of their release and their end-organ effects will identify new clinical indications and interventions that enhance their release. PMID:26376476

  12. Why mucosal health?

    USDA-ARS?s Scientific Manuscript database

    Aquaculture species depend more heavily on mucosal barriers than their terrestrial agricultural counterparts as they are continuously interacting with the aquatic microbiota. Unlike classical immune centers, such as the spleen and kidney, the accessibility of mucosal surfaces through immersion/dip t...

  13. Herbs in Oral Mucositis

    PubMed Central

    Baharvand, Maryam; Jafari, Soudeh

    2017-01-01

    Oral mucositis is an inflammatory mucosal destruction as a result of chemotherapy and/or radiation therapy, which in severe cases can impair patients’ quality of life. Moreover, mucosal infection and/or systemic involvement due to compromised immunity leads to delay or discontinuation of the treatment. Many strategies and agents have been suggested for the management of this condition. Because of their lower side effects compared to chemical drugs, general interest in evaluating therapeutic effects of herbs has been increased intensively. Herbal plants apply their effect through different mechanisms of action: antioxidant, analgesic, anti-inflammatory, antifungal, antiseptic, and anticarcinogenic activity. Recently, various natural agents in plants have been noticed in mucositis, which may improve the symptoms through different interventions. The purpose of this review is to focus on the preventive or therapeutic use of herbal medicine to alleviate oral mucositis. PMID:28511530

  14. Radiation Induced Oral Mucositis

    PubMed Central

    PS, Satheesh Kumar; Balan, Anita; Sankar, Arun; Bose, Tinky

    2009-01-01

    Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i) With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii) who also received concomitant chemotherapy; (iii) who received a total dose over 5,000 cGy; and (iv) who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene PMID:20668585

  15. Aquifer/aquitard interfaces: Mixing zones that enhance biogeochemical reactions

    USGS Publications Warehouse

    McMahon, P.B.

    2001-01-01

    Several important biogeochemical reactions are known to occur near the interface between aquifer and aquitard sediments. These reactions include O2 reduction; denitrification; and Fe3+, SO42-, and CO2 (methanogenesis) reduction. In some settings, these reactions occur on the aquitard side of the interface as electron acceptors move from the aquifer into the electron-donor-enriched aquitard. In other settings, these reactions occur on the aquifer side of the interface as electron donors move from the aquitard into the electron-acceptor-enriched, or microorganism-enriched, aquifer. Thus, the aquifer/aquitard interface represents a mixing zone capable of supporting greater microbial activity than either hydrogeologic unit alone. The extent to which biogeochemical reactions proceed in the mixing zone and the width of the mixing zone depend on several factors, including the abundance and solubility of electron acceptors and donors on either side of the interface and the rate at which electron acceptors and donors react and move across the interface. Biogeochemical reactions near the aquifer/aquitard interface can have a substantial influence on the chemistry of water in aquifers and on the chemistry of sediments near the interface.

  16. Sensory neurons signal for an increase in rat gastric mucosal blood flow in the face of pending acid injury.

    PubMed

    Holzer, P; Livingston, E H; Guth, P H

    1991-08-01

    Disruption of the gastric mucosal barrier is quickly followed by an increase in gastric mucosal blood flow, which is thought to be a defensive reaction to prevent further injury. This study examined how this increase in blood flow is brought about. When the stomach of urethane-anesthetized rats was perfused with 0.15N HCl, disruption of the gastric mucosal barrier with 15% ethanol increased the disappearance of acid from the gastric lumen and enhanced gastric mucosal blood flow. This increase in blood flow was blocked by local arterial infusion of tetrodotoxin (60 ng/min) to the stomach and by chemical ablation of capsaicin-sensitive sensory neurons. Inhibition of the blood flow increase was associated with exaggeration of gross and histological injury to the mucosa. IV injection of atropine (0.2 mg/kg) or pyrilamine (2 mg/kg) did not affect blood flow increase in response to barrier disruption, whereas morphine injection (2 mg/kg) inhibited it. The current findings show that the increase in gastric mucosal blood flow that follows disruption of the gastric mucosal barrier in the presence of acid is mediated by sensory neurons that seem to monitor acid back-diffusion and in turn signal for a protective increase in blood flow.

  17. The pathophysiology of extracellular hemoglobin associated with enhanced oxidative reactions

    PubMed Central

    Rifkind, Joseph M.; Mohanty, Joy G.; Nagababu, Enika

    2015-01-01

    Hemoglobin (Hb) continuously undergoes autoxidation producing superoxide which dismutates into hydrogen peroxide (H2O2) and is a potential source for subsequent oxidative reactions. Autoxidation is most pronounced under hypoxic conditions in the microcirculation and for unstable dimers formed at reduced Hb concentrations. In the red blood cell (RBC), oxidative reactions are inhibited by an extensive antioxidant system. For extracellular Hb, whether from hemolysis of RBCs and/or the infusion of Hb-based blood substitutes, the oxidative reactions are not completely neutralized by the available antioxidant system. Un-neutralized H2O2 oxidizes ferrous and ferric Hbs to Fe(IV)-ferrylHb and OxyferrylHb, respectively. FerrylHb further reacts with H2O2 producing heme degradation products and free iron. OxyferrylHb, in addition to Fe(IV) contains a free radical that can undergo additional oxidative reactions. Fe(III)Hb produced during Hb autoxidation also readily releases heme, an additional source for oxidative stress. These oxidation products are a potential source for oxidative reactions in the plasma, but to a greater extent when the lower molecular weight Hb dimers are taken up into cells and tissues. Heme and oxyferryl have been shown to have a proinflammatory effect further increasing their potential for oxidative stress. These oxidative reactions contribute to a number of pathological situations including atherosclerosis, kidney malfunction, sickle cell disease, and malaria. The toxic effects of extracellular Hb are of particular concern with hemolytic anemia where there is an increase in hemolysis. Hemolysis is further exacerbated in various diseases and their treatments. Blood transfusions are required whenever there is an appreciable decrease in RBCs due to hemolysis or blood loss. It is, therefore, essential that the transfused blood, whether stored RBCs or the blood obtained by an Autologous Blood Recovery System from the patient, do not further increase

  18. Mucosal immunization with a flagellin-adjuvanted Hgp44 vaccine enhances protective immune responses in a murine Porphyromonas gingivalis infection model.

    PubMed

    Puth, Sao; Hong, Seol Hee; Park, Mi Jin; Lee, Hye Hwa; Lee, Youn Suhk; Jeong, Kwangjoon; Kang, In-Chol; Koh, Jeong Tae; Moon, Byounggon; Park, Sang Chul; Rhee, Joon Haeng; Lee, Shee Eun

    2017-06-12

    Chronic periodontitis is caused by interactions between the oral polymicrobial community and host factors. Periodontal diseases are associated with dysbiotic shift in oral microbiota. Vaccination against periodontopathic bacteria could be a fundamental therapeutic to modulate polymicrobial biofilms. Because oral cavity is the site of periodontopathic bacterial colonization, mucosal vaccines should provide better protection than vaccines administered systemically. We previously reported that bacterial flagellin is an excellent mucosal adjuvant. In this study, we investigated whether mucosal immunization with a flagellin-adjuvanted polypeptide vaccine induces protective immune responses using a Porphyromonas gingivalis infection model. We employed the Hgp44 domain polypeptide of Arg-gingipain A (RgpA) as a mucosal antigen. Intranasal (IN) immunization induced a significantly higher Hgp44-specific IgG titer in the serum of mice than sublingual (SL) administration. The co-administration of flagellin potentiated serum IgG responses for both the IN and SL vaccinations. On the other hand, the anti-Hgp44-specific IgA titer in the saliva was comparable between IN and SL vaccinations, suggesting SL administration as more compliant vaccination route for periodontal vaccines. The co-administration of flagellin significantly potentiated the secretory IgA response in saliva also. Furthermore, mice administered a mixture of Hgp44 and flagellin via the IN and SL routes exhibited significant reductions in alveolar bone loss induced by live P. gingivalis infections. An intranasally administered Hgp44-flagellin fusion protein induced a comparable level of Hgp44-specific antibody responses to the mixture of Hgp44 and flagellin. Overall, a flagellin-adjuvanted Hgp44 antigen would serve an important component for a multivalent mucosal vaccine against polymicrobial periodontitis.

  19. Mucosally-directed adrenergic nerves and sympathomimetic drugs enhance non-intimate adherence of Escherichia coli O157:H7 to porcine cecum and colon

    PubMed Central

    Chen, Chunsheng; Lyte, Mark; Stevens, Mark P.; Vulchanova, Lucy; Brown, David R.

    2008-01-01

    The sympathetic neurotransmitter norepinephrine has been found to increase mucosal adherence of enterohemorrhagic Escherichia coli O157:H7 in explants of murine cecum and porcine distal colon. In the present study, we tested the hypothesis that norepinephrine augments the initial, loose adherence of this important pathogen to the intestinal mucosa. In mucosal sheets of porcine cecum or proximal, spiral and distal colon mounted in Ussing chambers, norepinephrine (10 µM, contraluminal addition) increased mucosal adherence of wild-type E. coli O157:H7 strain 85–170; in the cecal mucosa, this effect occurred within 15 – 90 min after bacterial inoculation. In addition, norepinephrine transiently increased short-circuit current in cecal and colonic mucosal sheets, a measure of active anion transport. Norepinephrine was effective in promoting cecal adherence of a non-O157 E. coli strain as well as E. coli O157:H7 eae or espA mutant strains that are incapable of intimate mucosal attachment. Nerve fibers immunoreactive for the norepinephrine synthetic enzyme dopamine β-hydroxylase appeared in close proximity to the cecal epithelium, and the norepinephrine reuptake blocker cocaine, like norepinephrine and the selective α2-adrenoceptor agonist UK-14,304, increased E. coli O157:H7 adherence. These results suggest that norepinephrine, acting upon the large bowel mucosa, modulates early, non-intimate adherence of E. coli O157:H7 and probably other mucosa-associated bacteria. Sympathetic nerves innervating the cecocolonic mucosa may link acute stress exposure or psychostimulant abuse with an increased microbial colonization of the intestinal surface. This in turn may alter host susceptibility to enteric infections. PMID:16687138

  20. Enhancing Paradynamics for QM/MM Sampling of Enzymatic Reactions.

    PubMed

    Lameira, Jerônimo; Kupchencko, Ilya; Warshel, Arieh

    2016-03-10

    Despite the enormous increase in computer power, it is still extremely challenging to obtain computationally converging sampling of ab initio QM/MM (QM(ai)/MM) free energy surfaces in condensed phases. The sampling problem can be significantly reduced by the use of the reference potential paradynamics (PD) approach, but even this approach still requires major computer time in studies of enzymatic reactions. To further reduce the sampling problem we developed here a new PD version where we use an empirical valence bond reference potential that has a minimum rather than a maximum at the transition state region of the target potential (this is accomplished conveniently by shifting the EVB of the product state). Hence, we can map the TS region in a more efficient way. Here, we introduce and validate the inverted EVB PD approach. The validation involves the study of the S(N)2 step of the reaction catalyzed by haloakene dehalogenase (DhlA) and the GTP hydrolysis in the RasGAP system. In addition, we have also studied the corresponding reaction in water for each of the systems described here and the reaction involving trimethylsulfonium and dimethylamine in solution. The results are encouraging and the new strategy appears to provide a powerful way of evaluating QM(ai)/MM activation free energies.

  1. Intranasal Mucosal Boosting with an Adenovirus-Vectored Vaccine Markedly Enhances the Protection of BCG-Primed Guinea Pigs against Pulmonary Tuberculosis

    PubMed Central

    Xing, Zhou; McFarland, Christine T.; Sallenave, Jean-Michel; Izzo, Angelo; Wang, Jun; McMurray, David N.

    2009-01-01

    Background Recombinant adenovirus-vectored (Ad) tuberculosis (TB) vaccine platform has demonstrated great potential to be used either as a stand-alone or a boost vaccine in murine models. However, Ad TB vaccine remains to be evaluated in a more relevant and sensitive guinea pig model of pulmonary TB. Many vaccine candidates shown to be effective in murine models have subsequently failed to pass the test in guinea pig models. Methods and Findings Specific pathogen-free guinea pigs were immunized with BCG, AdAg85A intranasally (i.n), AdAg85A intramuscularly (i.m), BCG boosted with AdAg85A i.n, BCG boosted with AdAg85A i.m, or treated only with saline. The animals were then infected by a low-dose aerosol of M. tuberculosis (M.tb). At the specified times, the animals were sacrificed and the levels of infection in the lung and spleen were assessed. In separate studies, the long-term disease outcome of infected animals was monitored until the termination of this study. Immunization with Ad vaccine alone had minimal beneficial effects. Immunization with BCG alone and BCG prime-Ad vaccine boost regimens significantly reduced the level of M.tb infection in the tissues to a similar extent. However, while BCG alone prolonged the survival of infected guinea pigs, the majority of BCG-immunized animals succumbed by 53 weeks post-M.tb challenge. In contrast, intranasal or intramuscular Ad vaccine boosting of BCG-primed animals markedly improved the survival rate with 60% of BCG/Ad i.n- and 40% of BCG/Ad i.m-immunized guinea pigs still surviving by 74 weeks post-aerosol challenge. Conclusions Boosting, particularly via the intranasal mucosal route, with AdAg85A vaccine is able to significantly enhance the long-term survival of BCG-primed guinea pigs following pulmonary M.tb challenge. Our results thus support further evaluation of this viral-vectored TB vaccine in clinical trials. PMID:19516906

  2. Plasmon-assisted chemical reactions revealed by high-vacuum tip-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lu, Shuaicheng; Sheng, Shaoxiang; Zhang, Zhenglong; Xu, Hongxing; Zheng, Hairong

    2014-08-01

    Tip-enhanced Raman spectroscopy (TERS) is the technique that combines the nanoscale spatial resolution of a scanning probe microscope and the highly sensitive Raman spectroscopy enhanced by the surface plasmons. It is suitable for chemical analysis at nanometer scale. Recently, TERS exhibited powerful potential in analyzing the chemical reactions at nanoscale. The high sensitivity and spatial resolution of TERS enable us to learn the reaction processes more clearly. More importantly, the chemical reaction in TERS is assisted by surface plasmons, which provides us an optical method to manipulate the chemical reactions at nanoscale. Here using our home-built high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) setup, we successfully observed the plasmon-assisted molecule dimerization and dissociation reactions. In HV-TERS system, under laser illumination, 4-nitrobenzenethiol (4NBT) molecules can be dimerized to p,p'-dimercaptoazobenzene (DMAB), and dissociation reaction occurs for malachite green (MG) molecules. Using our HV-TERS setup, the dynamic processes of the reactions are clearly revealed. The chemical reactions can be manipulated by controlling the plasmon intensity through changing the power of the incident laser, the tunneling current and the bias voltage. We also investigated the role of plasmonic thermal effect in the reactions by measuring both the Stokes and anti- Stokes Raman peaks. Our findings extend the applications of TERS, which can help to study the chemical reactions and understand the dynamic processes at single molecular level, and even design molecules by the plasmon-assisted chemical reactions.

  3. Experiments concerning the laser-enhanced reaction between vibrationally excited O3 and NO

    NASA Technical Reports Server (NTRS)

    Hui, K.-K.; Cool, T. A.

    1978-01-01

    The enhancement in reaction rate between O3 and NO is studied for the case of O3 vibrationally excited by a CO2 laser. Chemiluminescence observations of a vibrationally excited and an electronically excited nitrogen dioxide reaction product provide information on the separate contributions to the overall reaction rate of these two reactive channels. The contribution of the stretching and bending modes of O3 to the reaction rate enhancement is also discussed. In addition, consideration is given to the nonreactive vibrational deactivation of vibrationally excited O3.

  4. Enhancement of photosensitivity in the alcohol-added ferroin-catalyzed Belousov-Zhabotinsky reaction system

    NASA Astrophysics Data System (ADS)

    Jiro, Abe; Kazuhisa, Matsuda; Masakazu, Taka; Yasuo, Shirai

    1995-10-01

    The observation of photoinduced image formation in the alcohol-added ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction is reported. It is found that alcohol acts as a reagent that reduces the activation energy both of the ferroin-catalyzed and the Ce-catalyzed BZ reaction system and enhances the photosensitivity. By comparing the photosensitivity and photoinduced image formation for the ferroin-catalyzed BZ system with and without alcohol, we concluded that the photosensitivity of this alcohol-added BZ reaction system is enhanced by the presence of alcohol. This enhancement of the photosensitivity was confirmed in other alcohols such as ethanol, 1-propanol and 2-propanol.

  5. Fluctuation enhanced electrochemical reaction rates at the nanoscale

    PubMed Central

    García-Morales, Vladimir; Krischer, Katharina

    2010-01-01

    The electrode potential constitutes a dynamical variable whenever an electrode is resistively coupled to the electric circuit. We show that at the nanoscale, the discreteness and stochasticity of an electron transfer event causes fluctuations of the electrode potential that render all elementary electrochemical reactions to be faster on a nanoelectrode than predicted by the macroscopic (Butler–Volmer) electrochemical kinetics. This phenomenon is substantiated by means of a generalized (electro)chemical master equation. PMID:20176966

  6. Mucosal Health in Aquaculture

    USDA-ARS?s Scientific Manuscript database

    Abstract The mucosal surfaces (skin, gill, and intestine) constitute the first line of defense against pathogen invasion while simultaneously carrying out a diverse array of other critical physiological processes, including nutrient absorption, osmoregulation, and waste excretion. Aquaculture specie...

  7. Enhanced Olefin Cross Metathesis Reactions: The Copper Iodide Effect

    PubMed Central

    Voigtritter, Karl; Ghorai, Subir

    2011-01-01

    Copper iodide has been shown to be an effective co-catalyst for the olefin cross metathesis reaction. In particular, it has both a catalyst stabilizing effect due to iodide ion, as well as copper(I)-based phosphine-scavenging properties that apply to use of the Grubbs-2 catalyst. A variety of Michael acceptors and olefinic partners can be cross-coupled under mild conditions in refluxing diethyl ether that avoid chlorinated solvents. This effect has also been applied to chemistry in water at room temperature using the new surfactant TPGS-750-M. PMID:21528868

  8. Organic radicals for the enhancement of oxygen reduction reaction in Li-O2 batteries.

    PubMed

    Tesio, A Y; Blasi, D; Olivares-Marín, M; Ratera, I; Tonti, D; Veciana, J

    2015-12-25

    We examine for the first time the ability of inert carbon free-radicals as soluble redox mediators to catalyze and enhance the oxygen reduction reaction in a (TEGDME)-based electrolyte. We demonstrate that the tris(2,4,6-trichlorophenyl)methyl (TTM) radical is capable of chemically favoring the oxygen reduction reaction improving significantly the Li-O2 battery performance.

  9. Infrared chemiluminescence study of the reaction Cl + HI yielding HCl + I at enhanced collision energies.

    NASA Technical Reports Server (NTRS)

    Cowley, L. T.; Horne, D. S.; Polanyi, J. C.

    1971-01-01

    Performed chemiluminescence and beam experiments show a markedly increased efficiency of conversion of the reaction energy into vibration and a markedly enhanced tendency for forward scattering in the reaction Cl + HI yields HCl + I as compared with H + Cl2 yields HCl + Cl. These differences appear to be due predominantly to the difference in the masses involved.

  10. Tension-Enhanced Hydrogen Evolution Reaction on Vanadium Disulfide Monolayer

    NASA Astrophysics Data System (ADS)

    Pan, Hui

    2016-02-01

    Water electrolysis is an efficient way for hydrogen production. Finding efficient, cheap, and eco-friendly electrocatalysts is essential to the development of this technology. In the work, we present a first-principles study on the effects of tension on the hydrogen evolution reaction of a novel electrocatalyst, vanadium disulfide (VS2) monolayer. Two electrocatalytic processes, individual and collective processes, are investigated. We show that the catalytic ability of VS2 monolayer at higher hydrogen coverage can be efficiently improved by escalating tension. We find that the individual process is easier to occur in a wide range of hydrogen coverage and the collective process is possible at a certain hydrogen coverage under the same tension. The best hydrogen evolution reaction with near-zero Gibbs free energy can be achieved by tuning tension. We further show that the change of catalytic activity with tension and hydrogen coverage is induced by the change of free carrier density around the Fermi level, that is, higher carrier density, better catalytic performance. It is expected that tension can be a simple way to improve the catalytic activity, leading to the design of novel electrocatalysts for efficient hydrogen production from water electrolysis.

  11. Tension-Enhanced Hydrogen Evolution Reaction on Vanadium Disulfide Monolayer.

    PubMed

    Pan, Hui

    2016-12-01

    Water electrolysis is an efficient way for hydrogen production. Finding efficient, cheap, and eco-friendly electrocatalysts is essential to the development of this technology. In the work, we present a first-principles study on the effects of tension on the hydrogen evolution reaction of a novel electrocatalyst, vanadium disulfide (VS2) monolayer. Two electrocatalytic processes, individual and collective processes, are investigated. We show that the catalytic ability of VS2 monolayer at higher hydrogen coverage can be efficiently improved by escalating tension. We find that the individual process is easier to occur in a wide range of hydrogen coverage and the collective process is possible at a certain hydrogen coverage under the same tension. The best hydrogen evolution reaction with near-zero Gibbs free energy can be achieved by tuning tension. We further show that the change of catalytic activity with tension and hydrogen coverage is induced by the change of free carrier density around the Fermi level, that is, higher carrier density, better catalytic performance. It is expected that tension can be a simple way to improve the catalytic activity, leading to the design of novel electrocatalysts for efficient hydrogen production from water electrolysis.

  12. A novel retinoic acid, catechin hydrate and mustard oil-based emulsion for enhanced cytokine and antibody responses against multiple strains of HIV-1 following mucosal and systemic vaccinations

    PubMed Central

    Yu, Mingke; Vajdy, Michael

    2011-01-01

    Non-replicating protein- or DNA-based antigens generally require immune-enhancing adjuvants and delivery systems. It has been particularly difficult to raise antibodies against gp120 of HIV-1, which constitutes an important approach in HIV vaccine design. While almost all effort in adjuvant research has focused on mimicking the pathogens and the danger signals they engender in the host, relatively little effort has been spent on nutritive approaches. In this study, a new nutritive immune-enhancing delivery system (NIDS) composed of vitamin A, a polyphenol-flavonoid catechin hydrate, and mustard oil was tested for its adjuvant effect in immune responses against the gp120 protein of HIV-1CN54. Following a combination of two mucosal and two systemic vaccinations of mice, we found significant enhancement of both local and systemic antibodies as well as cytokine responses. These data have important implications for vaccine and adjuvant design against HIV-1 and other pathogens. PMID:21272602

  13. Aquifer/aquitard interfaces: mixing zones that enhance biogeochemical reactions

    NASA Astrophysics Data System (ADS)

    McMahon, P. B.

    2001-01-01

    Several important biogeochemical reactions are known to occur near the interface between aquifer and aquitard sediments. These reactions include O2 reduction; denitrification; and Fe3+, SO42-, and CO2 (methanogenesis) reduction. In some settings, these reactions occur on the aquitard side of the interface as electron acceptors move from the aquifer into the electron-donor-enriched aquitard. In other settings, these reactions occur on the aquifer side of the interface as electron donors move from the aquitard into the electron-acceptor-enriched, or microorganism-enriched, aquifer. Thus, the aquifer/aquitard interface represents a mixing zone capable of supporting greater microbial activity than either hydrogeologic unit alone. The extent to which biogeochemical reactions proceed in the mixing zone and the width of the mixing zone depend on several factors, including the abundance and solubility of electron acceptors and donors on either side of the interface and the rate at which electron acceptors and donors react and move across the interface. Biogeochemical reactions near the aquifer/aquitard interface can have a substantial influence on the chemistry of water in aquifers and on the chemistry of sediments near the interface. Résumé. Il se produit au voisinage de l'interface entre les aquifères et les imperméables plusieurs réactions biogéochimiques importantes. Il s'agit des réactions de réduction de l'oxygène, de la dénitrification et de la réduction de Fe3+, SO42- et CO2 (méthanogenèse). Dans certaines situations, ces réactions se produisent du côté imperméable de l'interface, avec des accepteurs d'électrons qui vont de l'aquifère vers l'imperméable riche en donneurs d'électrons. Dans d'autres situations, ces réactions se produisent du côté aquifère de l'interface, avec des donneurs d'électrons qui se déplacent de l'imperméable vers l'aquifère riche en accepteurs d'électrons ou en microorganismes. Ainsi, l'interface aquif

  14. A Gallium Oxide-Graphene Oxide Hybrid Composite for Enhanced Photocatalytic Reaction

    PubMed Central

    Kim, Seungdu; Han, Kook In; Lee, In Gyu; Park, Won Kyu; Yoon, Yeojoon; Yoo, Chan Sei; Yang, Woo Seok; Hwang, Wan Sik

    2016-01-01

    Hybrid composites (HCs) made up of gallium oxide (GaO) and graphene oxide (GO) were investigated with the intent of enhancing a photocatalytic reaction under ultraviolet (UV) radiation. The material properties of both GaO and GO were preserved, even after the formation of the HCs. The incorporation of the GO into the GaO significantly enhanced the photocatalytic reaction, as indicated by the amount of methylene blue (MB) degradation. The improvements in the reaction were discussed in terms of increased surface area and the retarded recombination of generated charged carriers. PMID:28335255

  15. Alterations in mucosal immunity identified in the colon of patients with irritable bowel syndrome.

    PubMed

    Aerssens, Jeroen; Camilleri, Michael; Talloen, Willem; Thielemans, Leen; Göhlmann, Hinrich W H; Van Den Wyngaert, Ilse; Thielemans, Theo; De Hoogt, Ronald; Andrews, Christopher N; Bharucha, Adil E; Carlson, Paula J; Busciglio, Irene; Burton, Duane D; Smyrk, Thomas; Urrutia, Raul; Coulie, Bernard

    2008-02-01

    Irritable bowel syndrome (IBS) has been associated with mucosal dysfunction, mild inflammation, and altered colonic bacteria. We used microarray expression profiling of sigmoid colon mucosa to assess whether there are stably expressed sets of genes that suggest there are objective molecular biomarkers associated with IBS. Gene expression profiling was performed using Human Genome U133 Plus 2.0 (Affymetrix) GeneChips with RNA from sigmoid colon mucosal biopsy specimens from 36 IBS patients and 25 healthy control subjects. Real-time quantitative polymerase chain reaction was used to confirm the data in 12 genes of interest. Statistical methods for microarray data were applied to search for differentially expressed genes, and to assess the stability of molecular signatures in IBS patients. Mucosal gene expression profiles were consistent across different sites within the sigmoid colon and were stable on repeat biopsy over approximately 3 months. Differentially expressed genes suggest functional alterations of several components of the host mucosal immune response to microbial pathogens. The most strikingly increased expression involved a yet uncharacterized gene, DKFZP564O0823. Identified specific genes suggest the hypothesis that molecular signatures may enable distinction of a subset of IBS patients from healthy controls. By using 75% of the biopsy specimens as a validation set to develop a gene profile, the test set (25%) was predicted correctly with approximately 70% accuracy. Mucosal gene expression analysis shows there are relatively stable alterations in colonic mucosal immunity in IBS. These molecular alterations provide the basis to test the hypothesis that objective biomarkers may be identified in IBS and enhance understanding of the disease.

  16. Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

    PubMed

    Collins, Gillian; Holmes, Justin D

    2016-07-01

    Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs.

  17. Accidental SUSY: enhanced bulk supersymmetry from brane back-reaction

    NASA Astrophysics Data System (ADS)

    Burgess, C. P.; van Nierop, L.; Parameswaran, S.; Salvio, A.; Williams, M.

    2013-02-01

    We compute how bulk loops renormalize both bulk and brane effective interactions for codimension-two branes in 6D gauged chiral supergravity, as functions of the brane tension and brane-localized flux. We do so by explicitly integrating out hyper- and gauge-multiplets in 6D gauged chiral supergravity compactified to 4D on a flux-stabilized 2D rugby-ball geometry, specializing the results of a companion paper, arXiv:1210.3753, to the supersymmetric case. While the brane back-reaction generically breaks supersymmetry, we show that the bulk supersymmetry can be preserved if the amount of brane- localized flux is related in a specific BPS-like way to the brane tension, and verify that the loop corrections to the brane curvature vanish in this special case. In these systems it is the brane-bulk couplings that fix the size of the extra dimensions, and we show that in some circumstances the bulk geometry dynamically adjusts to ensure the supersymmetric BPS-like condition is automatically satisfied. We investigate the robustness of this residual supersymmetry to loops of non-supersymmetric matter on the branes, and show that supersymmetry-breaking effects can enter only through effective brane-bulk interactions involving at least two derivatives. We comment on the relevance of this calculation to proposed applications of codimension-two 6D models to solutions of the hierarchy and cosmological constant problems.

  18. Characterization of photosynthetic reaction centers by surface-enhanced resonance Raman scattering

    NASA Astrophysics Data System (ADS)

    Chumanov, George D.; Cotton, Therese M.; Zhou, Chengli; Gaul, Dale; Picorel, Rafael; Seibert, Michael

    1993-06-01

    Surface-enhanced Resonance Raman scattering (SERRS) spectra were obtained for the reaction center complexes of the photosynthetic bacterium Rhodobacter sphaeroides (RC) and from photosystem II (PSII) of spinach, adsorbed on Ag and Au surfaces. These preliminary results demonstrate the considerable potential of this technique for selectively exciting resonance Raman scattering from reaction center components within their distinct absorption bands. Because of the high sensitivity afforded by SERRS, spectra could be measured from a single monolayer of reaction centers adsorbed on a metal surface. The surface-sensitivity provides new information indicating the topology of the PSII reaction center 47 kD light-harvesting protein complex. The activity of the PSII reaction center complex adsorbed on metal surfaces was monitored by photochemical reduction of cyt b-559. Measurement of fluorescence emission was shown to be a new and sensitive method for monitoring the structural and functional integrity of the PSII reaction center complex on the metal surface.

  19. Fermented milk with probiotic Lactobacillus rhamnosus S1K3 (MTCC5957) protects mice from salmonella by enhancing immune and nonimmune protection mechanisms at intestinal mucosal level.

    PubMed

    Kemgang, Tanedjeu Sonfack; Kapila, Suman; Shanmugam, Venkatesa Perumal; Reddi, Srinu; Kapila, Rajeev

    2016-04-01

    We investigated the mechanism by which an Indian indigenous probiotic culture, Lactobacillus rhamnosus S1K3, could overcome the pathogenic strain Salmonella enterica with an emphasis on the response at the intestinal mucosal level after long-term (30days) consumption. S1K3 was able to produce antimicrobial compounds against the pathogens. The probiotic adhered strongly to intestinal epithelium and maintained its integrity in presence of Salmonella through stimulation of tight junction and antimicrobial peptide genes in vitro. Mice prefed for 30days with S1K3-fermented milk exhibited low incidence of pathogenic Salmonella at mucosal and systemic levels. The probiotic induced TLRs transcripts at the Peyer's patches, followed by an increase in the Secretory-IgA in intestinal fluid, the IgA-secreting cells in lamina propria of small intestine and the IgA level in serum. Moreover, S1K3 maintained the protein level of IL-12, increased the IL-4 and reduced the TGF-β level in intestinal fluid/serum at the later stage of infection. All these actions concurred to lower the count of Salmonella in feces, its invasion in spleen, liver and intestine tissues and improved the health status of probiotic-fed group. In view of this performance, S1K3 appears to be a suitable candidate for the development of nutraceutical food.

  20. Enhanced mucosal immune responses against tetanus toxoid using novel delivery system comprised of chitosan-functionalized gold nanoparticles and botanical adjuvant: characterization, immunogenicity, and stability assessment.

    PubMed

    Barhate, Ganesh; Gautam, Manish; Gairola, Sunil; Jadhav, Suresh; Pokharkar, Varsha

    2014-11-01

    Approaches based on combined use of delivery systems and adjuvants are being favored to maximize efficient mucosal delivery of antigens. Here, we describe a novel delivery system comprised of chitosan-functionalized gold nanoparticles (CsAuNPs) and saponin-containing botanical adjuvant; Asparagus racemosus extract (ARE) for oral delivery of tetanus toxoid (TT). A significant increase in TT-specific IgG (34.53-fold) and IgA (43.75-fold) was observed when TT-CsAuNPs were formulated with ARE (TT-ARE-CsAuNPs). The local IgA immune responses for TT also showed a significant increase (106.5-fold in intestine washes and 99.74-fold in feces) with ARE-based formulations as compared with plain TT group. No effect of ARE was observed on size, charge, and loading properties of CsAuNPs. Additionally, no effect of ARE and CsAuNPs was observed on antigenicity and secondary structure of TT as determined by fluorescence, circular dichroism, and Fourier transform infrared spectroscopy. The stability studies demonstrated excellent stability profile of formulation at recommended storage conditions. The study establishes the possible role of immunomodulatory adjuvants in particulate delivery systems for mucosal delivery of vaccines.

  1. Recombinant cholera toxin B subunit (rCTB) as a mucosal adjuvant enhances induction of diphtheria and tetanus antitoxin antibodies in mice by intranasal administration with diphtheria-pertussis-tetanus (DPT) combination vaccine.

    PubMed

    Isaka, Masanori; Komiya, Takako; Takahashi, Motohide; Yasuda, Yoko; Taniguchi, Tooru; Zhao, Yanqiu; Matano, Keiko; Matsui, Hideyuki; Maeyama, Jun-Ichi; Morokuma, Kazunori; Ohkuma, Kunio; Goto, Norihisa; Tochikubo, Kunio

    2004-08-13

    Recombinant cholera toxin B subunit (rCTB) which is produced by Bacillus brevis carrying pNU212-CTB acts as a mucosal adjuvant capable of enhancing host immune responses specific to unrelated, mucosally co-administered vaccine antigens. When mice were administered intranasally with diphtheria-pertussis-tetanus (DPT) combination vaccine consisting of diphtheria toxoid (DTd), tetanus toxoid (TTd), pertussis toxoid (PTd), and formalin-treated filamentous hemagglutinin (fFHA), the presence of rCTB elevated constantly high values of DTd- and TTd-specific serum ELISA IgG antibody titres, and protective levels of diphtheria and tetanus toxin-neutralizing antibodies but the absence of rCTB did not. Moreover, the addition of rCTB protected all mice against tetanic symptoms and deaths. DPT combination vaccine raised high levels of serum anti-PT IgG antibody titres regardless of rCTB and protected mice from Bordetella pertussis challenge. These results suggest that co-administration of rCTB as an adjuvant is necessary for induction of diphtheria and tetanus antitoxin antibodies on the occasion of intranasal administration of DPT combination vaccine.

  2. The differences in colonic mucosal microbiota between normal individual and colon cancer patients by polymerase chain reaction-denaturing gradient gel electrophoresis.

    PubMed

    Huipeng, Wang; Lifeng, Gong; Chuang, Ge; Jiaying, Zhao; Yuankun, Cai

    2014-02-01

    The aim of this study was to analyze the differences in the intestinal composition between normal individuals and colon cancer patients. To establish the criteria for screening a normal individual for colon cancer, human colonic biopsies were obtained at routine colonoscopy. For patients with colon cancer, samples were obtained from cancerous regions. For normal individuals, colonic biopsies were taken from 3 sites of large intestine (descending, transverse, and ascending colon). Thereafter, a comparison of the microbiota structure by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was carried out. At last, bacterial species were identified by sequencing special bands from DGGE gels and comparing data with sequence databases. With PCR-DGGE, we have discovered that the diversity and richness of the bacterial community from colon cancer patient's colonic mucosa were lower than that of the normal individual's sample. Then, a special DGGE band was found in the colon cancer patients. After sequencing, we confirmed that it had a high level of similarity with bacteroides. Colon cancers are closely related with the alteration of intestinal flora such as the reduction of biodiversity and richness of the bacterial community. Furthermore, the increase in proportion of bacteroides may be directly associated with colon cancer.

  3. Cytokines and mucosal immunity.

    PubMed

    Bamias, Giorgos; Arseneau, Kristen O; Cominelli, Fabio

    2014-11-01

    Cytokines are integral mediators for maintaining intestinal mucosal homeostasis, as well as prominent effector molecules during chronic gut inflammatory diseases. This review focuses on recent studies of the role of specific cytokines in mucosal immunity. Dichotomous, or even opposing, functions have been described for several cytokines involved in intestinal innate immunity (most notably for members of the interleukin-1 family), which depend on the specific inflammatory conditions within the intestinal mucosa. For example, both interleukin-1α and interleukin-33 exhibit 'alarmin'-type properties that can signal tissue or cell damage, which further add to their well described proinflammatory roles. Costimulatory molecules of the tumor necrosis factor/tumor necrosis factor receptor superfamily, such as TNF-like cytokine 1A and LIGHT, are actively involved in mucosal proinflammatory pathways, but also may exert protection against infectious agents to facilitate recovery from acute inflammation. Finally, innate lymphoid cells are increasingly recognized as important cellular sources of pivotal mucosal cytokines, including the interleukin-23/T helper 17 cytokine, interleukin-22. Elucidating the complexity of cytokine signaling within the normal mucosa and during acute and chronic inflammation will be a pivotal step toward understanding the pathogenesis of immune-mediated gut diseases and developing effective therapies to treat them.

  4. Sphingosine kinase-1-dependent and -independent inhibitory effects of zanthoxyli fructus to attenuate the activation of mucosal mast cells and ameliorate food allergies in mice.

    PubMed

    Wang, Xiaoyu; Kageyama-Yahara, Natsuko; Hayashi, Shusaku; Yamamoto, Takeshi; Kadowaki, Makoto

    2012-01-01

    Food allergy (FA) is relatively a common disease in infants, but effective drug therapies are not yet available. Notably, mucosal mast cells, but not connective-tissue mast cells, play important roles in food allergic reactions via the release of inflammatory mediators. Therefore, we screened medicinal herb extracts for in vitro and in vivo antiallergic activity through inhibiting mucosal mast cell activation. As a result, both antigen-induced and calcium ionophore-induced degranulation was significantly inhibited by Zanthoxyli Fructus water extract (ZF) in mucosal-type murine bone marrow-derived mast cells (mBMMCs). ZF suppressed the antigen-induced [Ca(2+)](i) elevation and the antigen-enhanced mRNA expression of TNF-α, IL-4, and IL-13. The transcriptome and real-time PCR analyses revealed that ZF greatly decreased the antigen-enhanced expression level of sphingosine kinase 1 (Sphk1), which plays a key role in the FcεRI-mediated immune responses in mast cells. Furthermore, ZF inhibited allergic symptoms in an ovalbumin-caused murine FA model and decreased the number of infiltrating mucosal mast cells and the enhanced mRNA expression levels of IL-4 and Sphk1 in the FA mice colons. These results indicate that ZF suppresses mucosal mast cell activities mainly through Sphk1-dependent mechanism, and ZF is utilized for the development of a novel, potent anti-FA agent.

  5. Role of a Streambed's Benthic Biolayer in Enhancing Chemical Reactions in Hyporheic Flow

    NASA Astrophysics Data System (ADS)

    Harvey, J. W.

    2016-12-01

    Chemical processing of metals, nutrients, and organic compounds occurs throughout natural waters, however the rate of reactions often is greater at the streambed interface compared with surface water or deeper groundwater. Hydrologic exchange across the sediment interface brings reactive solutes and fine particulate organic matter from surface waters into contact with the streambed biolayer, a zone with algae and other living microflora and fauna, microbial communities, and reactive geochemical coatings on granular sediments. Compared with surface water or deeper hyporheic sediments, the intrinsic rate of reactions may be stimulated in biolayers because of higher rates of metabolic processing and associated redox reactions. Also, hydrologic transport may enhance reaction rates by relieving potential transport limitations through the re-supply of reactive substrates from surface water. As a result the chemical processing that occurs in the biolayer may far exceed processing that occurs in deeper hyporheic flow. Here I highlight new understanding of enhancement of reaction rates and their hydrologic and biogeochemical controls in streambed biolayers compared with hyporheic flow as a whole. The approach distinguishes and quantifies reaction limitation and transport limitation both at the centimeter-scale within the hyporheic zone and at the river network scale where the effect of streambed reactions accumulates and influences downstream water quality.

  6. Oral immunization with recombinant hepatitis E virus antigen displayed on the Lactococcus lactis surface enhances ORF2-specific mucosal and systemic immune responses in mice.

    PubMed

    Gao, Shenyang; Li, Dandan; Liu, Ying; Zha, Enhui; Zhou, Tiezhong; Yue, Xiqing

    2015-01-01

    Hepatitis E virus (HEV) as a recognized zoonotic pathogen has posed global burden on public health, which is exacerbated by lack of efficient vaccine. In this study, we constructed a recombinant (inaQ-ORF2 gene fusion) Lactococcus lactis (L. lactis) strain NZ3900 that expresses and displays the hepatitis E virus antigen ORF2 utilizing an ice uncleation protein-based anchor system. After oral vaccination of BALB/c mice, significantly higher levels of ORF2-specific mucosal IgA and serum IgG were detected and cellular immunity was also induced. These findings further support that L. lactis-based HEV antigen vaccines could be used for human and animal protection against infection.

  7. Cathodic current enhancement via manganese and oxygen related reactions in marine biofilms

    NASA Astrophysics Data System (ADS)

    Strom, Matthew James

    Corrosion is a threat that has economic, and environmental impacts worldwide. Many types of corrosive attack are the subject of ongoing research. One of these areas of research is microbiologically influenced corrosion, which is the enhancement and/or initiation of corrosion events caused by microorganisms. It is well known that colonies of microorganisms can enhance cathodic currents through biofilm formation. The aim of the present work was to elucidate the role of manganese in enhancing cathodic currents in the presence of biofilms. Repeated polarizations conducted in Delaware Bay waters, on biofilm coated Cr identified potentially sustainable reduction reactions. The reduction of MnO2 and the enhancement of the oxygen reduction reaction (ORR) were proven to be factors that influence cathodic current enhancement. The removal of ambient oxygen during polarizations resulted in a shutdown of cathodic current enhancement. These field data led to an exploration of the synergistic relationship between MnO2 and the ORR. Laboratory studies of the catalysis of peroxide disproportionation by MnO2 were monitored using a hanging mercury drop electrode. Experiments were run at an ambient sweater pH of 8 and pH 9, which simulated the near-surface conditions typical of cathodes immersed in seawater. Rapid reoxidation at the more basic pH was shown to allow manganese to behave as a persistent catalyst under the typical electrochemical surface conditions of a cathode. As a result a mechanism for ORR enhancement by manganese was proposed as a unique mechanism for cathodic current enhancement in biofilms. A separate field study of Delaware biofilms on stainless steel coupled to a sacrificial Al anode was carried out to identify the ORR enhancement mechanism and sustainable redox reactions at the cathode. Chemical treatments of glutaraldehyde and formaldoxime were applied to cathodes with biofilms to distinguish between enzymatic and MnO2 related ORR enhancement. The results ruled

  8. Dermatologic Reactions to Targeted Therapy: A Focus on Epidermal Growth Factor Receptor Inhibitors and Nursing Care.

    PubMed

    Barton-Burke, Margaret; Ciccolini, Kathryn; Mekas, Maria; Burke, Sean

    2017-03-01

    Cancer treatments usually have side effects of bone marrow depression, mucositis, hair loss, and gastrointestinal issues. Rarely do we think of skin side effects until patients have been treated successfully with epidermal growth factor receptor inhibitors (EGFRi). Those reactions include papulopustular rash, hair changes, radiation dermatitis enhancement, pruritus, mucositis, xerosis, fissures, and paronychia. This article discusses the common skin reactions seen when using EGFRi and presents an overview of skin as the largest and important organ of the body, including an overview of skin assessment, pathophysiology of the skin reactions, nursing care involved, and introduction to oncodermatology.

  9. Nucleosome linker proteins HMGB1 and histone H1 differentially enhance DNA ligation reactions.

    PubMed

    Yamanaka, Shiho; Katayama, Eisaku; Yoshioka, Ken-ichi; Nagaki, Sumiko; Yoshida, Michiteru; Teraoka, Hirobumi

    2002-03-22

    We previously reported that HMGB1, which originally binds to chromatin in a manner competitive with linker histone H1 to modulate chromatin structure, enhances both intra-molecular and inter-molecular ligations. In this paper, we found that histone H1 differentially enhances ligation reaction of DNA double-strand breaks (DSB). Histone H1 stimulated exclusively inter-molecular ligation reaction of DSB with DNA ligase IIIbeta and IV, whereas HMGB1 enhanced mainly intra-molecular ligation reaction. Electron microscopy of direct DNA-protein interaction without chemical cross-linking visualized that HMGB1 bends and loops linear DNA to form compact DNA structure and that histone H1 is capable of assembling DNA in tandem arrangement with occasional branches. These results suggest that differences in the enhancement of DNA ligation reaction are due to those in alteration of DNA configuration induced by these two linker proteins. HMGB1 and histone H1 may function in non-homologous end-joining of DSB repair and V(D)J recombination in different manners.

  10. Enhancement of Nuclear Reactions due to Screening Effects of Core Electrons

    NASA Astrophysics Data System (ADS)

    Luo, N.; Shrestha, P. J.; Miley, G. H.; Violante, V.

    2005-12-01

    Recent progress in understanding the screening effects of core level atomic electrons is summarized in this paper. Some preliminary results on core electron screening were reported before.1 The studies focus on two types of nuclear reactions in some metal lattices: fusion between deuterons and also proton capture by medium and heavy lattice nuclei. In both reactions the energy of the light nuclear species, proton or deuteron, is on the keV (1000 eV) scale, while that of heavy nuclei is essentially zero. A standard atomic code is used to obtain the core electron charge density and the potential profile in the metal atom. This Hartree-Fock-Slater type code was originally written by Herman and Skillman2 and later modified by others and available online.3 For the D-D reaction, the charge density obtained then gives an estimate on the screening length. The corresponding enhancement in Coulomb barrier tunneling can be obtained from this data. For the proton capture reaction, an ion dynamic code4 written to simulate the motion of keV protons in Pd/Ni lattice, CLAIRE, was modified to take into account the realistic atomic potential, including core electron contributions. In both cases, our result shows a significant nuclear reaction enhancement. The reaction rate calculated roughly matches the scale of excess heat observed in some metal hydride/deuteride5 experiments.

  11. Hydrocarbon-water-rock interaction: Redox reaction as a mechanism for sandstone reservoir porosity enhancement

    SciTech Connect

    Shebl, M.A.; Surdam, R.C.

    1995-06-01

    Experiments evaluated the potential for and extent of oil-water-rock reactions in hydrocarbon reservoirs. Results indicate not only that significant potential exists for redox reactions between oxidized mineral phases and crude oil, but that such reactions can significantly alter porosity and permeability characteristics of an elastic hydrocarbon reservoir. The red (oxidized) sandstones used in the redox experiment initially contained 10 to 25% carbonate, anhydrite, and intergranular clay cements. Porosity ranged from 6 to 15%. The sandstones were gray or white after experimentation, and porosity increased 12 to 20% over original values, primarily due to carbonate dissolution. It is suggested that during the redox experiments, the iron oxides ({+-} sulphate) were reduced and hydrocarbon was oxidized to produce oxygenated organic compounds (e.g., organic acid anions, CO{sub 2}). These redox reaction products destabilized the carbonate cements and enhanced sandstone porosity. It is concluded that redox reactions involving crude oil and the mineral matrix of these reservoir rocks in the presence of H{sub 2}O do occur and may result in significantly enhanced porosity. Hydrocarbon emplacement and the resultant redox reactions can cause bleaching and changes in porosity and permeability. This relationship is well documented in the Wingate, White Rim, and Tensleep sandstones. The hydrocarbon reservoir units are white to gray and have good porosity and permeability. The adjacent non-reservoir units are red (due to hematite staining), and have good carbonate cementation and poor porosity and permeability, confining hydrocarbon flow to the nearby reservoir units or associated fractures.

  12. Mucosal melanoma: an update.

    PubMed

    Ballester Sánchez, R; de Unamuno Bustos, B; Navarro Mira, M; Botella Estrada, R

    2015-03-01

    Mucosal melanoma is a rare melanoma subtype that differs from the cutaneous form of the tumor in its biology, clinical manifestations, and management. Diagnosis is usually late due to a lack of early or specific signs and the location of lesions in areas that are difficult to access on physical examination. Surgical excision is the treatment of choice for localized disease. The value of sentinel lymph node biopsy and lymphadenectomy is still unclear. Radiotherapy can be used as adjuvant therapy for the control of local disease. c-KIT mutations are more common than in other types of melanoma and this has led to significant advances in the use of imatinib for the treatment of metastatic mucosal melanoma. Copyright © 2014 Elsevier España, S.L.U. and AEDV. All rights reserved.

  13. A visible light-induced photocatalytic silver enhancement reaction for gravimetric biosensors.

    PubMed

    Ko, Wooree; Yim, Changyong; Jung, Namchul; Joo, Jinmyoung; Jeon, Sangmin; Seo, Hyejung; Lee, Soo Suk; Park, Jae Chan

    2011-10-07

    We have developed a novel microgravimetric immunosensor using a WO(3) nanoparticle-modified immunoassay and a silver enhancement reaction. When the nanoparticles in silver ion solution (i.e.  AgNO(3)) are exposed to visible light, the silver ions are photocatalytically reduced and form a metallic silver coating on the nanoparticles. This silver coating consequently induces changes in the mass and light absorption spectrum. Although photocatalytic reduction reactions can be achieved using ultraviolet (UV) light and TiO(2) nanoparticles as described in our previous publication (Seo et al 2010 Nanotechnology 21 505502), the use of UV light in biosensing applications has drawbacks in that UV light can damage proteins. In addition, conventional quartz crystal substrates must be passivated to prevent undesirable silver ion reduction on their gold-coated sensing surfaces. We addressed these problems by adopting a visible light-induced photocatalytic silver enhancement method using WO(3) nanoparticles and lateral field excited (LFE) quartz crystals. As a proof-of-concept demonstration of the technique, streptavidin was adsorbed onto an LFE quartz crystal, and its mass was enhanced with biotinylated WO(3) nanoparticles, this being followed by a photocatalytic silver enhancement reaction. The mass change due to the enhancement was found to be > 30 times greater than the mass change obtained with the streptavidin alone.

  14. Communication: Enhanced oxygen reduction reaction and its underlying mechanism in Pd-Ir-Co trimetallic alloys

    SciTech Connect

    Ham, Hyung Chul; Hwang, Gyeong S.; Manogaran, Dhivya; Lee, Kang Hee; Jin, Seon-ah; You, Dae Jong; Pak, Chanho; Kwon, Kyungjung

    2013-11-28

    Based on a combined density functional theory and experimental study, we present that the electrochemical activity of Pd{sub 3}Co alloy catalysts toward oxygen reduction reaction (ORR) can be enhanced by adding a small amount of Ir. While Ir tends to favorably exist in the subsurface layers, the underlying Ir atoms are found to cause a substantial modification in the surface electronic structure. As a consequence, we find that the activation barriers of O/OH hydrogenation reactions are noticeably lowered, which would be mainly responsible for the enhanced ORR activity. Furthermore, our study suggests that the presence of Ir in the near-surface region can suppress Co out-diffusion from the Pd{sub 3}Co substrate, thereby improving the durability of Pd-Ir-Co catalysts. We also discuss the relative roles played by Ir and Co in enhancing the ORR activity relative to monometallic Pd catalysts.

  15. Enhanced reactivity for hydrogen reactions at Pt nanoislands on Au(111).

    PubMed

    Wolfschmidt, Holger; Weingarth, Daniel; Stimming, Ulrich

    2010-05-17

    We report high exchange current densities exceeding 1 A cm(-2) at Pt nanostructures on Au(111) for hydrogen-related reactions. Such activity is found at Pt nanoparticles with a coverage of less than 10 % of a monolayer on Au(111) and on single Pt particles deposited on Au(111). Potential pulse technique as well as micropolarization curves with overpotentials of +/-10 mV were used in the case of extended nanostructured surfaces to determine the activity. Single Pt particles were investigated in an in situ electrochemical scanning tunneling microscope setup using the STM tip as local sensor. The reactivity obtained on Pt nanostructured Au(111) towards hydrogen reactions were subsidized by single particle reactivity measurements. The specific activity of platinum is enhanced by more than a factor of 1000 as compared to a Pt(111) single crystal. Aspects that may explain this enhancement such as an involvement of the substrate, highly reactive defect sites and enhanced mass transport are discussed.

  16. Enhanced mucosal immunoglobulin A response and solid protection against foot-and-mouth disease virus challenge induced by a novel dendrimeric peptide.

    PubMed

    Cubillos, Carolina; de la Torre, Beatriz G; Jakab, Annamaria; Clementi, Giorgia; Borrás, Eva; Bárcena, Juan; Andreu, David; Sobrino, Francisco; Blanco, Esther

    2008-07-01

    The successful use of a dendrimeric peptide to protect pigs against challenge with foot-and-mouth disease virus (FMDV), which causes the most devastating animal disease worldwide, is described. Animals were immunized intramuscularly with a peptide containing one copy of a FMDV T-cell epitope and branching out into four copies of a B-cell epitope. The four immunized pigs did not develop significant clinical signs upon FMDV challenge, neither systemic nor mucosal FMDV replication, nor was its transmission to contact control pigs observed. The dendrimeric construction specifically induced high titers of FMDV-neutralizing antibodies and activated FMDV-specific T cells. Interestingly, a potent anti-FMDV immunoglobulin A response (local and systemic) was observed, despite the parenteral administration of the peptide. On the other hand, peptide-immunized animals showed no antibodies specific of FMDV infection, which qualifies the peptide as a potential marker vaccine. Overall, the dendrimeric peptide used elicited an immune response comparable to that found for control FMDV-infected pigs that correlated with a solid protection against FMDV challenge. Dendrimeric designs of this type may hold substantial promise for peptide subunit vaccine development.

  17. Trehalose enhances osmotic tolerance and suppresses lysophosphatidylcholine-induced acrosome reaction in ram spermatozoon.

    PubMed

    Ahmad, E; Naseer, Z; Aksoy, M; Küçük, N; Uçan, U; Serin, I; Ceylan, A

    2015-09-01

    This study was aimed to investigate the influence of trehalose on osmotic tolerance and the ability of ram spermatozoon to undergo acrosome reaction induced by lysophosphatidylcholine (LPC). In experiment 1, the diluted ejaculates were exposed to anisosmotic fructose solutions (70, 500, 750 and 1000 mOsm l(-1) ) with or without 50 mm trehalose. The presence of trehalose in hyperosmotic conditions enhanced (P < 0.05) the percentage of live, live-intact and intact spermatozoa. Similarly, trehalose enhanced (P < 0.05) the live and live-intact spermatozoa during hypo-osmotic conditions. In experiment 2, the centrifuged ejaculates were diluted with TCG only or TCG containing either 50 or 100 mm trehalose. The acrosome reaction was induced by LPC. The percentage of acrosome-reacted spermatozoon was less (P < 0.05) in trehalose-supplemented groups compared to control. In experiment 3, the ejaculates were cryopreserved in an extender containing 0 mm (control), 50 mm or 100 mm trehalose. Supplementation of extender with trehalose, either 50 mm or 100 mm, enhanced the cryosurvival rate (P < 0.05) compared to the control. In conclusion, the presence of trehalose in anisosmotic conditions enhances the osmotic tolerance, cryosurvival rate of ram spermatozoon and suppresses their ability to undergo LPC and cryo-induced acrosome reaction.

  18. Mucosal adaptation to aspirin induced gastric damage in humans. Studies on blood flow, gastric mucosal growth, and neutrophil activation.

    PubMed Central

    Konturek, J W; Dembinski, A; Stoll, R; Domschke, W; Konturek, S J

    1994-01-01

    The gastropathy associated with the ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin is a common side effect of this class of drugs, but the precise mechanisms by which they cause mucosal damage have not been fully explained. During continued use of an injurious substance, such as aspirin, the extent of gastric mucosal damage decreases and this phenomenon is named gastric adaptation. To assess the extent of mucosal damage by aspirin and subsequent adaptation the effects of 14 days of continuous, oral administration of aspirin (2 g per day) to eight healthy male volunteers was studied. To estimate the rate of mucosal damage, gastroscopy was performed before (day 0) and at days 3, 7, 14 of aspirin treatment. Gastric microbleeding and gastric mucosal blood flow were measured using laser Doppler flowmeter and mucosal biopsy specimens were taken for the estimation of tissue DNA synthesis and RNA and DNA concentration. In addition, the activation of neutrophils in peripheral blood was assessed by measuring their ability to associate with platelets. Aspirin induced acute damage mainly in gastric corpus, reaching at day 3 about 3.5 on the endoscopic Lanza score but lessened to about 1.5 at day 14 pointing to the occurrence of gastric adaptation. Mucosal blood flow increased at day 3 by about 50% in the gastric corpus and by 88% in the antrum. The in vitro DNA synthesis and RNA concentration, an index of mucosal growth, were reduced at day 3 but then increased to reach about 150% of initial value at the end of aspirin treatment. It is concluded that the treatment with aspirin in humans induces gastric adaptation to this agent, which entails the increase in mucosal blood flow, the rise in neutrophil activation, and the enhancement in mucosal growth. PMID:7959223

  19. Montanide IMS 1313 N VG PR nanoparticle adjuvant enhances antigen-specific immune responses to profilin following mucosal vaccination against Eimeria acervulina.

    PubMed

    Jang, Seung I; Lillehoj, Hyun S; Lee, Sung Hyen; Lee, Kyung Woo; Lillehoj, Erik P; Bertrand, François; Dupuis, Laurent; Deville, Sébastien

    2011-12-15

    This study investigated protection against Eimeria acervulina (E. acervulina) following vaccination of chickens with an Eimeria recombinant profilin in conjunction with different adjuvants, or by changing the route of administration of the adjuvants. Day-old broilers were immunized twice with profilin emulsified in Montanide IMS 1313 N VG PR adjuvant (oral, nasal, or ocular routes), Montanide ISA 71 VG adjuvant (subcutaneous route), or Freund's adjuvant (subcutaneous route) and orally challenged with virulent E. acervulina parasites. Birds orally immunized with profilin plus IMS 1313 N VG PR, or subcutaneously immunized with profilin plus ISA 71 VG, had increased body weight gains compared with animals nasally or ocularly immunized with profilin plus IMS 1313 N VG PR, or subcutaneously immunized with profilin plus Freund's adjuvant. All adjuvant formulations, except for IMS 1313 N VG PR given by the nasal or ocular routes, decreased fecal parasite excretion and/or reduced intestinal lesions, compared with non-vaccinated and infected controls. Compared with animals vaccinated with profilin plus Freund's adjuvant, chickens immunized with profilin plus IMS 1313 N VG PR or ISA 71 VG showed higher post-infection intestinal levels of profilin-reactive IgY and secretary IgA antibodies. Finally, immunization with profilin in combination with ISA 71 VG was consistently better than profilin plus IMS 1313 N VG PR or Freund's adjuvant for increasing the percentages of CD4(+), CD8(+), BU1(+), TCR1(+), and TCR2(+) intestinal lymphocytes. These results indicate that experimental immunization of chickens with the recombinant profilin subunit vaccine in conjunction with IMS 1313 or ISA 71 VG adjuvants increases protective mucosal immunity against E. acervulina infection. Published by Elsevier B.V.

  20. Lactobacilli and Bifidobacteria enhance mucosal B cell responses and differentially modulate systemic antibody responses to an oral human rotavirus vaccine in a neonatal gnotobiotic pig disease model

    PubMed Central

    Kandasamy, Sukumar; Chattha, Kuldeep S; Vlasova, Anastasia N; Rajashekara, Gireesh; Saif, Linda J

    2014-01-01

    B cells play a key role in generation of protective immunity against rotavirus infection, a major cause of gastroenteritis in children. Current RV vaccines are less effective in developing countries compared to developed countries. Commensals/probiotics influence mucosal immunity, but the role of early gut colonizing bacteria in modulating intestinal B cell responses to RV vaccines is largely unknown. We co-colonized neonatal gnotobiotic pigs, the only animal model susceptible to HRV diarrhea, with 2 dominant bacterial species present in the gut of breastfed infants, Lactobacillus rhamnosus strain GG and Bifidobacterium animalis lactis Bb12 to evaluate their impact on B cell responses to an attenuated (Att) human rotavirus (HRV) Wa strain vaccine. Following HRV challenge, probiotic-colonized, AttHRV vaccinated piglets had significantly lower fecal scores and reduced HRV shedding titers compared to uncolonized, AttHRV vaccinated pigs. The reduction in HRV diarrhea was significantly correlated with higher intestinal IgA HRV antibody titers and intestinal HRV-specific IgA antibody secreting cell (ASC) numbers in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs. The significantly higher small intestinal HRV IgA antibody responses coincided with higher IL-6, IL-10 and APRIL responses of ileal mononuclear cells (MNCs) and the immunomodulatory effects of probiotics genomic DNA on TGF-β and IL-10 responses. However, serum RV IgG antibody titers and total IgG titers were significantly lower in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs, both pre- and post-challenge. In summary, LGG and Bb12 beneficially modulated intestinal B cell responses to HRV vaccine. PMID:25483333

  1. Lactobacilli and Bifidobacteria enhance mucosal B cell responses and differentially modulate systemic antibody responses to an oral human rotavirus vaccine in a neonatal gnotobiotic pig disease model.

    PubMed

    Kandasamy, Sukumar; Chattha, Kuldeep S; Vlasova, Anastasia N; Rajashekara, Gireesh; Saif, Linda J

    2014-01-01

    B cells play a key role in generation of protective immunity against rotavirus infection, a major cause of gastroenteritis in children. Current RV vaccines are less effective in developing countries compared to developed countries. Commensals/probiotics influence mucosal immunity, but the role of early gut colonizing bacteria in modulating intestinal B cell responses to RV vaccines is largely unknown. We co-colonized neonatal gnotobiotic pigs, the only animal model susceptible to HRV diarrhea, with 2 dominant bacterial species present in the gut of breastfed infants, Lactobacillus rhamnosus strain GG and Bifidobacterium animalis lactis Bb12 to evaluate their impact on B cell responses to an attenuated (Att) human rotavirus (HRV) Wa strain vaccine. Following HRV challenge, probiotic-colonized, AttHRV vaccinated piglets had significantly lower fecal scores and reduced HRV shedding titers compared to uncolonized, AttHRV vaccinated pigs. The reduction in HRV diarrhea was significantly correlated with higher intestinal IgA HRV antibody titers and intestinal HRV-specific IgA antibody secreting cell (ASC) numbers in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs. The significantly higher small intestinal HRV IgA antibody responses coincided with higher IL-6, IL-10 and APRIL responses of ileal mononuclear cells (MNCs) and the immunomodulatory effects of probiotics genomic DNA on TGF-β and IL-10 responses. However, serum RV IgG antibody titers and total IgG titers were significantly lower in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs, both pre- and post-challenge. In summary, LGG and Bb12 beneficially modulated intestinal B cell responses to HRV vaccine.

  2. Dynamics and Kinetics Study of "In-Water" Chemical Reactions by Enhanced Sampling of Reactive Trajectories.

    PubMed

    Zhang, Jun; Yang, Y Isaac; Yang, Lijiang; Gao, Yi Qin

    2015-11-12

    High potential energy barriers and engagement of solvent coordinates set challenges for in silico studies of chemical reactions, and one is quite commonly limited to study reactions along predefined reaction coordinate(s). A systematic protocol, QM/MM MD simulations using enhanced sampling of reactive trajectories (ESoRT), is established to quantitatively study chemical transitions in complex systems. A number of trajectories for Claisen rearrangement in water and toluene were collected and analyzed, respectively. Evidence was found that the bond making and breaking during this reaction are concerted processes in solutions, preferentially through a chairlike configuration. Water plays an important dynamic role that helps stabilize the transition sate, and the dipole-dipole interaction between water and the solute also lowers the transition barrier. The calculated rate coefficient is consistent with the experimental measurement. Compared with water, the reaction pathway in toluene is "narrower" and the reaction rate is slower by almost three orders of magnitude due to the absence of proper interactions to stabilize the transition state. This study suggests that the "in-water" nature of the Claisen rearrangement in aqueous solution influences its thermodynamics, kinetics, as well as dynamics.

  3. Modeling of Sheath Ion-Molecule Reactions in Plasma Enhanced Chemical Vapor Deposition of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Govindan, T. R.; Meyyappan, M.

    2004-01-01

    In many plasma simulations, ion-molecule reactions are modeled using ion energy independent reaction rate coefficients that are taken from low temperature selected-ion flow tube experiments. Only exothermic or nearly thermoneutral reactions are considered. This is appropriate for plasma applications such as high-density plasma sources in which sheaths are collisionless and ion temperatures 111 the bulk p!asma do not deviate significantly from the gas temperature. However, for applications at high pressure and large sheath voltages, this assumption does not hold as the sheaths are collisional and ions gain significant energy in the sheaths from Joule heating. Ion temperatures and thus reaction rates vary significantly across the discharge, and endothermic reactions become important in the sheaths. One such application is plasma enhanced chemical vapor deposition of carbon nanotubes in which dc discharges are struck at pressures between 1-20 Torr with applied voltages in the range of 500-700 V. The present work investigates The importance of the inclusion of ion energy dependent ion-molecule reaction rates and the role of collision induced dissociation in generating radicals from the feedstock used in carbon nanotube growth.

  4. Development of enhancing agglutination reaction using gold nanoparticle for pre-transfusion testing.

    PubMed

    Choktaweesak, N; Krasathong, P; Ammaranond, P

    2016-10-01

    To explore an alternative way for antibody detection testing, the examination of gold nanoparticle solution for enhancing unexpected antibodies for pre-transfusion testing was investigated. Exposure of foreign antigens on red blood cells from transfusion can trigger the immune system to produce unexpected antibodies. This immunological response may cause the complication to future transfusion. For detection of unexpected antibodies, the antibody screening test is performed approximately 30-60 min. To reduce turnaround time, enhancing reagent, low-ionic strength solution (LISS), is widely used. However, cost of enhancing reagent is an issue which has concerned in resource limited countries. Gold nanoparticle solution can increase red blood cells agglutination reaction. To solve this issue, study of gold nanoparticle solution was investigated. Samples were performed comparing between LISS and gold nanoparticle solution at antiglobulin phase. After reading the agglutination reaction, supernatants were collected and measured at the optical density at 760 nm by spectrophotometer. The optical density in the tube of gold nanoparticle solution was higher than in the tube of 2-5% cell suspension and monoclonal antibody. It has been observed that gold nanoparticle solution enhanced the reaction of agglutination 98% while LISS enhanced the agglutination only 60·8%. Employing a commercially available enhancing reagent, parallel samples confirmed results providing validation of the assay. It approximately costs $1 US dollars compared to $30 for a commercially available reagent. The low cost and yet effective time-consuming test for antibody screening is a practical and viable solution alternative way for performing in antibody screening test in resource limited countries. © 2016 British Blood Transfusion Society.

  5. [Mucositis in head and neck cancer patients undergoing radiochemotherapy].

    PubMed

    Santos, Renata Cristina Schmidt; Dias, Rodrigo Souza; Giordani, Adelmo José; Segreto, Roberto Araújo; Segreto, Helena Regina Comodo

    2011-12-01

    The objective of present study was to classify oral mucositis according to the Common Toxicity Criterion (CTC) international parameters in head and neck tumor patients simultaneously treated with radio and chemotherapy, and characterize a patient profile in our area, observing the individuals' habits, tumor characteristics, treatment protocol and acute reaction intensity. Fifty patients undergoing simultaneous 66 to 70 Gy megavoltage radiotherapy and cisplatin/carboplatin chemotherapy were evaluated in this study. Weekly evaluations of the degree of mucositis were perfoemed according to CTC, a four-degree ordinal scale; 36% of all patients and 100% of those with diabetes discontinued treatment due to mucositis, showing that this pathology contributes to the severity of mucositis.

  6. Enzyme immunoassay by dynamic enhanced vibrational spectroscopy of the enzyme reaction product

    NASA Astrophysics Data System (ADS)

    Zhao, Haiying; Dou, Xiaoming

    2005-01-01

    This paper reports a kind of application of surface-enhanced Raman scattering (SERS) to immunology. In the proposed system, antibody immobilized on a solid substrate reacts with antigen, which binds with another antibody labeled with peroxidase. If this immunocomplex is subjected to reaction with o-phenylenediamine and hydrogenperoxide at 37°C, azoaniline is generated. This azo compound is adsorbed on a silver colloid and only the azo compound gives a strong surface-enhanced resonance Raman (SERRS) spectrum. A linear relationship was observed between the peak intensity of the N=N stretching band and the concentration of antigen, revealing that one can determine the concentration of antigen by the SERRS measurement of the reaction product.

  7. Humoral immune responses among mucosal and cutaneous leishmaniasis patients caused by Leishmania braziliensis.

    PubMed

    Valli, L C; Passos, V M; Dietze, R; Callahan, H L; Berman, J D; Grogl, M

    1999-12-01

    Mucosal leishmaniasis is arguably the most morbid sequelae of cutaneous leishmaniasis. The importance of early diagnosis for effective therapy, coupled with the difficulty of diagnosing the disease parasitologically, prompted this investigation of humoral immune markers of mucosal disease. Promastigote soluble antigens of Leishmania braziliensis, isolated from cutaneous and mucosal lesions, were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis; antigens were identified by immunoblotting with parasite-specific IgG antibody-positive sera of patients with mucosal disease (n = 18) and cutaneous disease (n = 23). For antigens of the cutaneous parasite WR 2095, mucosal sera generally reacted intensely to antigens of 75, 66, and 45 kDa and weakly to 48-50-kDa antigens, whereas cutaneous sera generally detected weakly the first 3 antigens and intensely the latter doublet. The data suggest that the transition from the cutaneous antigenic profile to a mucosal antigenic profile could be used to predict mucosal disease in approximately half of mucosal patients. An additional finding was that antibodies present in the sera of patients with mucosal disease labeled a 66-kDa peptide of normal human lip mucosa more intensely than did cutaneous sera. Autoimmune processes stimulated by the reaction of IgG, originally directed against the 66-kDa of L. braziliensis, to the 66-kDa antigen of mucosal tissue may contribute to the clinical presentation of mucosal leishmaniasis.

  8. (Gold core)@(ceria shell) nanostructures for plasmon-enhanced catalytic reactions under visible light.

    PubMed

    Li, Benxia; Gu, Ting; Ming, Tian; Wang, Junxin; Wang, Peng; Wang, Jianfang; Yu, Jimmy C

    2014-08-26

    Driving catalytic reactions with sunlight is an excellent example of sustainable chemistry. A prerequisite of solar-driven catalytic reactions is the development of photocatalysts with high solar-harvesting efficiencies and catalytic activities. Herein, we describe a general approach for uniformly coating ceria on monometallic and bimetallic nanocrystals through heterogeneous nucleation and growth. The method allows for control of the shape, size, and type of the metal core as well as the thickness of the ceria shell. The plasmon shifts of the Au@CeO2 nanostructures resulting from the switching between Ce(IV) and Ce(III) are observed. The selective oxidation of benzyl alcohol to benzaldehyde, one of the fundamental reactions for organic synthesis, performed under both broad-band and monochromatic light, demonstrates the visible-light-driven catalytic activity and reveals the synergistic effect on the enhanced catalysis of the Au@CeO2 nanostructures.

  9. Field Effect Enhanced Hydrogen Evolution Reaction of MoS2 Nanosheets.

    PubMed

    Wang, Junhui; Yan, Mengyu; Zhao, Kangning; Liao, Xiaobin; Wang, Peiyao; Pan, Xuelei; Yang, Wei; Mai, Liqiang

    2017-02-01

    Hydrogen evolution reaction performance of MoS2 can be enhanced through electric-field-facilitated electron transport. The best catalytic performance of a MoS2 nanosheet can achieve an overpotential of 38 mV (100 mA cm(-2) ) at gate voltage of 5 V, the strategy of utilizing the electric field can be used in other semiconductor materials to improve their electrochemical catalysis for future relevant research.

  10. [Structural characteristics of infrared spectra for polyaluminum chloride in enhanced reactions of modification].

    PubMed

    Zhou, Feng-shan; Wang, Shi-hu; Su, Jin-zhu; Sun, Hu; Ding, Jie; Xu, Yi-zhuang; Wu, Jin-guang

    2004-05-01

    As an important preparation method of Inorganic Polymer Flocculants (IPFs) with all-round performance, the use of enhanced reactions of modification for Polyaluminum Chlorides (PAC) is a trend of application. In this paper, auctorial-made multicore oligomers as a complexing agent, polysilicate as a crosslinking agent and polyacrylamide as a compounding agent are respectively used to enhance PAC and prepared three kinds of IPFs, named CO-PAC, CR-PAC and PAM-PAC. The Fourier Transform Infrared spectra (FTIR) of the three flocculants show that there have been found new chemical bonds beyond Al-OH in their structures, and each characteristic band of primary group in PAC has a band shift to a lower frequency due to its structural aberration. These evidences suggested that enhanced reactions of modification for PAC are not at all a simple process of physical mix, but a chemical reaction to form other structural characteristics of inorganic polymers. The excellent coagulation behavior of these new flocculants depends mainly on the chemical actions, but there are a little physical effects between the modifiers and PAC.

  11. Organizing a mucosal defense.

    PubMed

    Newberry, Rodney D; Lorenz, Robin G

    2005-08-01

    Gastrointestinal associated lymphoid tissue can be divided into loosely organized effector sites, which include the lamina propria and intraepithelial lymphocytes, and more organized structures, such as mesenteric lymph nodes (LNs), Peyer's patches (PPs), isolated lymphoid follicles, and cryptopatches (CPs). These organized structures in the gastrointestinal tract have been hypothesized to play the role of primary lymphoid organ, supporting the extrathymic development of T lymphocytes (CPs), secondary lymphoid organs involved in the induction of the mucosal immune response (PPs), and tertiary lymphoid structures whose function is still under debate (isolated lymphoid follicles). The most widely studied lymphoid structure found in the small intestine is the PP. PPs are secondary lymphoid structures, and their development and function have been extensively investigated. However, single lymphoid aggregates resembling PPs have been also described in humans and in the murine small intestines. These isolated lymphoid follicles have both germinal centers and an overlying follicle-associated epithelium, suggesting that they also can function as inductive sites for the mucosal immune response. This review compares and contrasts the development and function of the four main organized gastrointestinal lymphoid tissues: CPs, isolated lymphoid follicles, PPs, and mesenteric LNs.

  12. Reaction mechanisms for enhancing mineral sequestration of CO{sub 2}

    SciTech Connect

    Karalee Jarvis; R.W. Carpenter; Todd Windman; Youngchul Kim; Ryan Nunez; Firas Alawneh

    2009-08-15

    Storage of CO{sub 2} through mineral sequestration using olivine has been shown to produce environmentally benign carbonates. However, due to the formation of a rate-limiting reaction product layer, the rate of reaction is insufficient for large-scale applications. We report the results of altering the reactant solution composition and the resultant reaction mechanism to enhance the reaction rate. The products were analyzed for total carbon content with thermal decomposition analysis, product phase compositions with Debye-Scherrer X-ray powder diffraction (XRD), surface morphology with scanning electron microscopy (SEM), and composition with energy dispersive X-ray spectroscopy (EDXS). Carbon analysis showed that an increase in bicarbonate ion activity increased the olivine to carbonate conversion rate. The fastest conversion rate, 63% conversion in one hour, occurred in a solution of 5.5 M KHCO{sub 3}. Additionally, SEM confirmed that when the bicarbonate ion activity was increased, magnesium carbonate product particles significantly increased in both number density and size and the rate passivating-reaction layer exfoliation was augmented. 30 refs., 5 figs., 1 tab.

  13. Plasmon-enhanced reverse water gas shift reaction over oxide supported Au catalysts

    SciTech Connect

    Upadhye, AA; Ro, I; Zeng, X; Kim, HJ; Tejedor, I; Anderson, MA; Dumesic, JA; Huber, GW

    2015-01-01

    We show that localized surface plasmon resonance (LSPR) can enhance the catalytic activities of different oxide-supported Au catalysts for the reverse water gas shift (RWGS) reaction. Oxide-supported Au catalysts showed 30 to 1300% higher activity for RWGS under visible light compared to dark conditions. Au/TiO2 catalyst prepared by the deposition-precipitation (DP) method with 3.5 nm average Au particle size showed the highest activity for the RWGS reaction. Visible light is converted into chemical energy for this reaction with up to a 5% overall efficiency. A shift in the apparent activation energy (from 47 kJ mol(-1) in dark to 35 kJ mol(-1) in light) and apparent reaction order with respect to CO2 (from 0.5 in dark to 1.0 in light) occurs due to the LSPR. Our kinetic results indicate that the LSPR increases the rate of either the hydroxyl hydrogenation or carboxyl decomposition more than any other steps in the reaction network.

  14. Stakeholder perspectives and reactions to "academic" cognitive enhancement: Unsuspected meaning of ambivalence and analogies.

    PubMed

    Forlini, Cynthia; Racine, Eric

    2012-07-01

    The existence of diverging discourses in the media and academia on the use of prescription medications to improve cognition in healthy individuals, i.e. "cognitive enhancement" (CE) creates the need to better understand perspectives from stakeholders. This qualitative focus-group study examined perspectives from students, parents and healthcare providers on CE. Stakeholders expressed ambivalence regarding CE (i.e. reactions to, definitions of, risks, and benefits). They were reluctant to adopt analogies to performance-enhancing steroids and caffeine though these analogies were useful in discussing concepts common to the use of different performance-enhancing substances. Media coverage of CE was criticized for lack of scientific rigor, ethical clarity, and inadvertent promotion of CE. Ambivalence of stakeholders suggests fundamental discomfort with economic and social driving forces of CE. Forms of public dialogue that voice the unease and ambivalence of stakeholders should be pursued to avoid opting hastily for permissive or restrictive health policies for CE.

  15. Wave speeds for the FKPP equation with enhancements of the reaction function

    NASA Astrophysics Data System (ADS)

    Dumortier, Freddy; Kaper, Tasso J.

    2015-06-01

    In classes of N-particle systems and lattice models, the speed of front propagation is approximated by that of the corresponding continuum model, and for many such systems, the rate of convergence to the continuum speed is known to be slow as N → ∞. This slow convergence has been captured by including a cutoff function on the reaction terms in the continuum models. For example, the Fisher-Kolmogorov-Petrowskii-Piscounov (FKPP) equation with a cutoff has fronts that travel at the speed , which agrees well with data from numerical simulations of the corresponding N-particle systems, where c FKPP is the linear spreading speed. In Panja and van Saarloos (Phys Rev E 66:015206, 2002), an example is presented in which a small enhancement of the reaction function causes the propagation speeds of fronts to be larger than c FKPP. Such front speeds are also observed in stochastic lattice models where the growth rates in the regime of few particles are modified. In this article, we analyze the dynamics of traveling fronts in the FKPP equation with the constant enhancement function employed by Panja and van Saarloos. We present formulas for the wave speeds, develop the criteria on the parameters for which the front speeds are larger than the linear spreading speed even in the limit in which the size of the cutoff domain vanishes, study the rate of approach as N → ∞, and identify the mechanisms in phase space by which the constant enhancement of the reaction function makes possible the larger than linear wave speeds. In addition, we extend these results to the FKPP equation with two other enhancement functions, which are also of interest for continuum level modeling of lattice models and many-particle systems in the regimes of small numbers of particles, namely a linear enhancement function and an enhancement that is uniform above the linearized reaction function. We also derive explicit formulas for the parameters in these problems. The mathematical techniques used

  16. Intranasal Immunization with DOTAP Cationic Liposomes Combined with DC-Cholesterol Induces Potent Antigen-Specific Mucosal and Systemic Immune Responses in Mice.

    PubMed

    Tada, Rui; Hidaka, Akira; Iwase, Naoko; Takahashi, Saeko; Yamakita, Yuki; Iwata, Tomoko; Muto, Shoko; Sato, Emi; Takayama, Noriko; Honjo, Emi; Kiyono, Hiroshi; Kunisawa, Jun; Aramaki, Yukihiko

    2015-01-01

    Despite the progress made by modern medicine, infectious diseases remain one of the most important threats to human health. Vaccination against pathogens is one of the primary methods used to prevent and treat infectious diseases that cause illness and death. Vaccines administered by the mucosal route are potentially a promising strategy to combat infectious diseases since mucosal surfaces are a major route of entry for most pathogens. However, this route of vaccination is not widely used in the clinic due to the lack of a safe and effective mucosal adjuvant. Therefore, the development of safe and effective mucosal adjuvants is key to preventing infectious diseases by enabling the use of mucosal vaccines in the clinic. In this study, we show that intranasal administration of a cationic liposome composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] (DC-chol) (DOTAP/DC-chol liposome) has a potent mucosal adjuvant effect in mice. Intranasal vaccination with ovalbumin (OVA) in combination with DOTAP/DC-chol liposomes induced the production of OVA-specific IgA in nasal tissues and increased serum IgG1 levels, suggesting that the cationic DOTAP/DC-chol liposome leads to the induction of a Th2 immune response. Additionally, nasal-associated lymphoid tissue and splenocytes from mice treated with OVA plus DOTAP/DC-chol liposome showed high levels of IL-4 expression. DOTAP/DC-chol liposomes also enhanced OVA uptake by CD11c+ dendritic cells in nasal-associated lymphoid tissue. These data demonstrate that DOTAP/DC-chol liposomes elicit immune responses via an antigen-specific Th2 reaction. These results suggest that cationic liposomes merit further development as a mucosal adjuvant for vaccination against infectious diseases.

  17. Intranasal Immunization with DOTAP Cationic Liposomes Combined with DC-Cholesterol Induces Potent Antigen-Specific Mucosal and Systemic Immune Responses in Mice

    PubMed Central

    Iwase, Naoko; Takahashi, Saeko; Yamakita, Yuki; Iwata, Tomoko; Muto, Shoko; Sato, Emi; Takayama, Noriko; Honjo, Emi; Kiyono, Hiroshi; Kunisawa, Jun; Aramaki, Yukihiko

    2015-01-01

    Despite the progress made by modern medicine, infectious diseases remain one of the most important threats to human health. Vaccination against pathogens is one of the primary methods used to prevent and treat infectious diseases that cause illness and death. Vaccines administered by the mucosal route are potentially a promising strategy to combat infectious diseases since mucosal surfaces are a major route of entry for most pathogens. However, this route of vaccination is not widely used in the clinic due to the lack of a safe and effective mucosal adjuvant. Therefore, the development of safe and effective mucosal adjuvants is key to preventing infectious diseases by enabling the use of mucosal vaccines in the clinic. In this study, we show that intranasal administration of a cationic liposome composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] (DC-chol) (DOTAP/DC-chol liposome) has a potent mucosal adjuvant effect in mice. Intranasal vaccination with ovalbumin (OVA) in combination with DOTAP/DC-chol liposomes induced the production of OVA-specific IgA in nasal tissues and increased serum IgG1 levels, suggesting that the cationic DOTAP/DC-chol liposome leads to the induction of a Th2 immune response. Additionally, nasal-associated lymphoid tissue and splenocytes from mice treated with OVA plus DOTAP/DC-chol liposome showed high levels of IL–4 expression. DOTAP/DC-chol liposomes also enhanced OVA uptake by CD11c+ dendritic cells in nasal-associated lymphoid tissue. These data demonstrate that DOTAP/DC-chol liposomes elicit immune responses via an antigen-specific Th2 reaction. These results suggest that cationic liposomes merit further development as a mucosal adjuvant for vaccination against infectious diseases. PMID:26440657

  18. Alleviating mucositis: are we on track for a novel therapeutic?

    PubMed

    Lalla, Rajesh V

    2015-02-01

    Oral and gastrointestinal mucositis has emerged as an important toxicity of cancer therapy. In addition to supportive care measures, agents for the prevention or treatment of mucositis in specific patient populations are described in the evidence-based clinical practice guidelines published by the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. However, there still remains an unmet clinical need for preventive and therapeutic agents in several patient populations. The successful development of such agents will rely on our improved understanding of the pathogenic mechanisms underlying mucositis. Studies are also underway on novel delivery mechanisms and risk prediction models that can facilitate the selective use of interventions for mucositis in a targeted and cost-effective manner. A large number of agents are at various stages in the clinical development pipeline. Enhanced management of this dose-limiting toxicity will allow the delivery of optimal cancer therapy and improve patient prognosis.

  19. Mucosal biofilms of Candida albicans.

    PubMed

    Ganguly, Shantanu; Mitchell, Aaron P

    2011-08-01

    Biofilms are microbial communities that form on surfaces and are embedded in an extracellular matrix. C. albicans forms pathogenic mucosal biofilms that are evoked by changes in host immunity or mucosal ecology. Mucosal surfaces are inhabited by many microbial species; hence these biofilms are polymicrobial. Several recent studies have applied paradigms of biofilm analysis to study mucosal C. albicans infections. These studies reveal that the Bcr1 transcription factor is a master regulator of C. albicans biofilm formation under diverse conditions, though the most relevant Bcr1 target genes can vary with the biofilm niche. An important determinant of mucosal biofilm formation is the interaction with host defenses. Finally, studies of interactions between bacterial species and C. albicans provide insight into the communication mechanisms that endow polymicrobial biofilms with unique properties.

  20. Near-Infrared Plasmonic-Enhanced Solar Energy Harvest for Highly Efficient Photocatalytic Reactions.

    PubMed

    Cui, Jiabin; Li, Yongjia; Liu, Lei; Chen, Lin; Xu, Jun; Ma, Jingwen; Fang, Gang; Zhu, Enbo; Wu, Hao; Zhao, Lixia; Wang, Leyu; Huang, Yu

    2015-10-14

    We report a highly efficient photocatalyst comprised of Cu7S4@Pd heteronanostructures with plasmonic absorption in the near-infrared (NIR)-range. Our results indicated that the strong NIR plasmonic absorption of Cu7S4@Pd facilitated hot carrier transfer from Cu7S4 to Pd, which subsequently promoted the catalytic reactions on Pd metallic surface. We confirmed such enhancement mechanism could effectively boost the sunlight utilization in a wide range of photocatalytic reactions, including the Suzuki coupling reaction, hydrogenation of nitrobenzene, and oxidation of benzyl alcohol. Even under irradiation at 1500 nm with low power density (0.45 W/cm(2)), these heteronanostructures demonstrated excellent catalytic activities. Under solar illumination with power density as low as 40 mW/cm(2), nearly 80-100% of conversion was achieved within 2 h for all three types of organic reactions. Furthermore, recycling experiments showed the Cu7S4@Pd were stable and could retain their structures and high activity after five cycles. The reported synthetic protocol can be easily extended to other Cu7S4@M (M = Pt, Ag, Au) catalysts, offering a new solution to design and fabricate highly effective photocatalysts with broad material choices for efficient conversion of solar energy to chemical energy in an environmentally friendly manner.

  1. Process for the oxidation of materials in water at supercritical temperatures utilizing reaction rate enhancers

    SciTech Connect

    Swallow, K.C.; Killilea, W.R.; Hong, G.T.; Bourhis, A.L.

    1993-08-03

    A method is described for substantially completely oxidizing combustible materials in which an aqueous stream bearing the combustible materials is reacted in the presence of an oxidant comprising diatomic oxygen and at a temperature greater than the critical temperature of water and at a pressure greater than about 25 bar, within a reactor for a period of less than about 5 minutes to produce a reaction product stream, wherein the reaction is initiated in the presence of a rate enhancer comprising at least one oxidizing agent in addition to said oxidant selected from the group consisting of ozone, hydrogen peroxide, salts containing persulfate, salts containing permanganate, nitric acid, salts containing nitrate, oxyacids of chlorine and their corresponding salts, hypochlorous acid, salts containing hypochlorite, chlorous acid, salts containing chlorite, chloric acid, salts containing chlorate, perchloric acid, and salts containing perchlorate.

  2. Bimodal and trimodal multisensory enhancement: effects of stimulus onset and intensity on reaction time.

    PubMed

    Diederich, Adele; Colonius, Hans

    2004-11-01

    Manual reaction times to visual, auditory, and tactile stimuli presented simultaneously, or with a delay, were measured to test for multisensory interaction effects in a simple detection task with redundant signals. Responses to trimodal stimulus combinations were faster than those to bimodal combinations, which in turn were faster than reactions to unimodal stimuli. Response enhancement increased with decreasing auditory and tactile stimulus intensity and was a U-shaped function of stimulus onset asynchrony. Distribution inequality tests indicated that the multisensory interaction effects were larger than predicted by separate activation models, including the difference between bimodal and trimodal response facilitation. The results are discussed with respect to previous findings in a focused attention task and are compared with multisensory integration rules observed in bimodal and trimodal superior colliculus neurons in the cat and monkey.

  3. Three Dimensional Hybrids of Vertical Graphene-nanosheet Sandwiched by Ag-nanoparticles for Enhanced Surface Selectively Catalytic Reactions

    PubMed Central

    Zhao, Jing; Sun, Mentao; Liu, Zhe; Quan, Baogang; Gu, Changzhi; Li, Junjie

    2015-01-01

    Three dimensional (3D) plasmonic nanostructure is perfect for the surface-enhanced Raman scattering (SERS) and also very suitable for surface catalytic reaction, but how to design and fabricate is still a robust task. Here, we show a 3D plasmonic nanohybrid of vertical graphene-nanosheet sandwiched by Ag-nanoparticles on the silicon nanocone array substrate for enhanced surface catalytic reaction. By SERS detection, we find that this hierarchical nanohybrid structure is highly efficient in the enhancement of catalytic reaction, even at a very low concentration of 10−11 M, which is far better than previous reports by four orders of magnitude. A strong electric field enhancement produced in the 3D framework nanohybrids of graphene nanosheet/Ag-nanoparticles is responsible for this great enhancement of catalytic reaction, due to larger electron collective oscillation in the composite system. Especially the oxygen adsorbed on the graphene and Ag nanoparticles can be excited to triplet excited states, and the electrons on the graphene and the nanoparticles can be effectively transferred to the oxygen, which plays very important role in molecular catalytic reactions. Our results demonstrate the contribution of graphene in plasmon-driven catalytic reactions, revealing a co-driven reaction process.This excellent SERS substrate can be used for future plasmon and graphene co-catalytic surface catalytic reactions, graphene-based surface plasmon sensors and so on. PMID:26522142

  4. Risk analysis, diagnosis and management of gastrointestinal mucositis in pediatric cancer patients.

    PubMed

    Kuiken, Nicoline S S; Rings, Edmond H H M; Tissing, Wim J E

    2015-04-01

    Mucositis is a complex inflammatory reaction of the mucous membranes of the alimentary tract upon chemotherapy and radiotherapy treatment in oncology patients. Mucositis can be subdivided in oral and gastrointestinal mucositis (GI mucositis). The damage to the gastrointestinal tract compromises the intestinal function and thereby the nutritional status and the quality of life, and eventually affects survival. The literature on GI mucositis focuses mainly on adults. This review focuses on data available on GI mucositis in pediatric cancer patients. An evaluation of the clinical presentation and consequences of GI mucositis in children is outlined. The review summarizes key issues for clinicians with respect to risk analysis for developing mucositis and the diagnosis of this condition in children. Information on these issues is obtained from clinical trials in children and adults, and from animal models. Diagnostic tools and assessment of severity of GI mucositis in children is elaborated on. Furthermore, the clinical management of the symptoms and consequences of GI mucositis in children, with specific focus on nutritional support, are discussed.

  5. Enhancement of nitrite on heme-induced oxidative reactions: A potential toxicological implication.

    PubMed

    Lu, Naihao; Chen, Wei; Zhu, Jingjie; Peng, Yi-Yuan

    2012-02-01

    Evidence to support the role of heme as major inducers of oxidative damage is increasingly present. Nitrite (NO(2)(-)) is one of the major end products of NO metabolism. Although the biological significance of heme/NO(2)(-)-mediated protein tyrosine nitration is a subject of great interest, the important roles of NO(2)(-) on heme-dependent redox reaction have been greatly underestimated. In this study, we investigated the influence of NO(2)(-) on heme -dependent oxidative reactions. It was found that NO(2)(-) had the capacity to act as a reducing agent to remove high oxidation states of heme iron. In the reduction of ferryl heme to ferric heme, NO(2)(-) was oxidized to a nitrating agent NO(2), and subsequently, tyrosine residues in bovine serum albumin (BSA) were nitrated. However, the presence of NO(2)(-) surprisingly exerted pro-oxidant effect on heme-H(2)O(2)-induced formation of BSA carbonyls at lower concentrations and enhanced the loss of HepG2 cell viability dose-dependently, which was probably due to the ability of this inorganic compound to efficiently enhance the peroxidase activity and oxidative degradation of heme. These data provide novel evidence that the dietary intake and experimental use of NO(2)(-) in vivo and in vitro would possess the pro-oxidant activity through interfering in heme-dependent oxidative reactions. Besides the classic role in protein tyrosine nitration, the deleterious effects on heme redox reactions may provide new insights into the toxicological implications of NO(2)(-) with cellular heme proteins. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Oral lichen planus and lichenoid mucositis.

    PubMed

    De Rossi, Scott S; Ciarrocca, Katharine

    2014-04-01

    Oral lichen planus (OLP) is commonly found in middle-aged women. Although the cause is unknown, research points to several complex immunologic events and cells that are responsible for the inflammatory destruction and chronicity of these lesions. Biopsy for histologic diagnosis is recommended. The mainstay of treatment remains topical corticosteroids; however, newer therapies such as immunomodulating agents are available for recalcitrant lesions. In cases of lichenoid mucositis or reactions, treatment should be directed at identifying and removing the presumed cause. Given the apparent risk of squamous cell carcinoma in these patients, frequent follow-up and repeat biopsy are vital.

  7. Energetic composite and system with enhanced mechanical sensitivity to initiation of self-sustained reaction

    DOEpatents

    Gash, Alexander E [Brentwood, CA; Barbee, Jr., Troy W.

    2012-05-29

    An energetic composition and system using amassed energetic multilayer pieces which are formed from the division, such as for example by cutting, scoring, breaking, crushing, shearing, etc., of a mechanically activatable monolithic energetic multilayer(s) (e.g. macro-scale sheets of multilayer films), for enhancing the sensitivity of the energetic composite and system to mechanical initiation of self-sustained reaction. In particular, mechanical initiation of the energetic composition may be achieved with significantly lower mechanical energy inputs than that typically required for initiating the monolithic energetic multilayers from which it is derived.

  8. Oleylamine-functionalized palladium nanoparticles with enhanced electrocatalytic activity for the oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Shi, Yi; Yin, Shengkang; Ma, Yanrong; Lu, Dingkun; Chen, Yu; Tang, Yawen; Lu, Tianhong

    2014-01-01

    The oleylamine (OAm)-functionalized Pd nanoparticles (Pd-OAm) have been conveniently synthesized through direct thermal decomposition method of low cost palladium acetate. The morphology, crystalline structure and composition of the Pd-OAm are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Fourier transform infrared (FT-IR) spectroscopy, XPS and zeta potential analysis confirm the successful immobilization of OAm molecules on the Pd nanoparticles surface. The Pd-OAm displays an enhanced electrocatalytic activity and formic acid-tolerant ability for the oxygen reduction reaction (ORR), suggesting a potential application in cathodic catalyst for direct formic acid fuel cells.

  9. Mucosal Targeting of a BoNT/A Subunit Vaccine Adjuvanted with a Mast Cell Activator Enhances Induction of BoNT/A Neutralizing Antibodies in Rabbits

    PubMed Central

    Staats, Herman F.; Fielhauer, Jeffrey R.; Thompson, Afton L.; Tripp, Alice A.; Sobel, Ashley E.; Maddaloni, Massimo; Abraham, Soman N.; Pascual, David W.

    2011-01-01

    Background We previously reported that the immunogenicity of Hcβtre, a botulinum neurotoxin A (BoNT/A) immunogen, was enhanced by fusion to an epithelial cell binding domain, Ad2F, when nasally delivered to mice with cholera toxin (CT). This study was performed to determine if Ad2F would enhance the nasal immunogenicity of Hcβtre in rabbits, an animal model with a nasal cavity anatomy similar to humans. Since CT is not safe for human use, we also tested the adjuvant activity of compound 48/80 (C48/80), a mast cell activating compound previously determined to safely exhibit nasal adjuvant activity in mice. Methods New Zealand White or Dutch Belted rabbits were nasally immunized with Hcβtre or Hcβtre-Ad2F alone or combined with CT or C48/80, and serum samples were tested for the presence of Hcβtre-specific binding (ELISA) or BoNT/A neutralizing antibodies. Results Hcβtre-Ad2F nasally administered with CT induced serum anti-Hcβtre IgG ELISA and BoNT/A neutralizing antibody titers greater than those induced by Hcβtre + CT. C48/80 provided significant nasal adjuvant activity and induced BoNT/A-neutralizing antibodies similar to those induced by CT. Conclusions Ad2F enhanced the nasal immunogenicity of Hcβtre, and the mast cell activator C48/80 was an effective adjuvant for nasal immunization in rabbits, an animal model with a nasal cavity anatomy similar to that in humans. PMID:21304600

  10. Intracluster reactions in phenylacetylene ammonia clusters initiated through resonant enhanced ionization

    SciTech Connect

    Breen, J.J.; Tzeng, W.; Kilgore, K.; Keesee, R.G.; Castleman A.W. Jr.

    1989-01-01

    Protonated ammonia clusters of specific size are observed to form following the resonant enhanced ionization of phenylacetylene--ammonia clusters PAx(NH/sub 3/)/sub n/ in the 0/sup 0//sub 0/ region of the S/sub 1/--S/sub 0/ transition of the (unclustered) PA. The resonance enhanced absorption of two photons, approx. =8.8 eV total energy, are found to cause intracluster reactions for ngreater than or equal to5. The findings imply that the adiabatic ionization potential of (NH/sub 3/)/sub 4/ is greater than 8.8 eV, while that of (NH/sub 3/)/sub 5/ is (slightly) less.

  11. Deep Sub-Barrier Fusion Enhancement in the {sup 6}He+{sup 206}Pb Reaction

    SciTech Connect

    Penionzhkevich, Yu.E.; Zagrebaev, V.I.; Lukyanov, S.M.; Kalpakchieva, R.

    2006-04-28

    The fusion of {sup 6}He with {sup 206}Pb has been studied at energies close to and below the Coulomb barrier. The experiment was carried out at the Dubna Radioactive Ion Beams complex of FLNR, JINR. The {sup 6}He beam intensity was about 5x10{sup 6} pps, the maximum energy being 60.3{+-}0.4 MeV. The yield of the {sup 210}Po isotope, produced in the 2n-evaporation channel, demonstrates an extremely large enhancement of the sub-barrier fusion cross section as compared with the {sup 4}He+{sup 208}Pb reaction. This enhancement is most likely due to the mechanism of 'sequential fusion' with an intermediate neutron transfer from {sup 6}He to the Pb nucleus with positive Q values.

  12. Enhancement Effect of Noble Metals on Manganese Oxide for the Oxygen Evolution Reaction.

    PubMed

    Seitz, Linsey C; Hersbach, Thomas J P; Nordlund, Dennis; Jaramillo, Thomas F

    2015-10-15

    Developing improved catalysts for the oxygen evolution reaction (OER) is key to the advancement of a number of renewable energy technologies, including solar fuels production and metal air batteries. In this study, we employ electrochemical methods and synchrotron techniques to systematically investigate interactions between metal oxides and noble metals that lead to enhanced OER catalysis for water oxidation. In particular, we synthesize porous MnOx films together with nanoparticles of Au, Pd, Pt, or Ag and observe significant improvement in activity for the combined catalysts. Soft X-ray absorption spectroscopy (XAS) shows that increased activity correlates with increased Mn oxidation states to 4+ under OER conditions compared to bare MnOx, which exhibits minimal OER current and remains in a 3+ oxidation state. Thickness studies of bare MnOx films and of MnOx films deposited on Au nanoparticles reveal trends suggesting that the enhancement in activity arises from interfacial sites between Au and MnOx.

  13. Significant enhancement of the Stille reaction with a new combination of reagents-copper(I) iodide with cesium fluoride.

    PubMed

    Mee, Simon P H; Lee, Victor; Baldwin, Jack E

    2005-05-20

    The combination of copper(I) iodide and cesium fluoride significantly enhances the Stille reaction. After extensive optimisation, a variety of electronically unfavourable and sterically hindered substrates were coupled in very high yields under mild conditions.

  14. Bifidobacterium bifidum OLB6378 Simultaneously Enhances Systemic and Mucosal Humoral Immunity in Low Birth Weight Infants: A Non-Randomized Study

    PubMed Central

    Tanaka, Katsunori; Tsukahara, Takamitsu; Yanagi, Takahide; Nakahara, Sayuri; Furukawa, Ouki; Tsutsui, Hidemi; Koshida, Shigeki

    2017-01-01

    Probiotic supplementation has been part of the discussion on methods to enhance humoral immunity. Administration of Bifidobacterium bifidum OLB6378 (OLB6378) reduced the incidence of late-onset sepsis in infants. In this non-randomized study, we aimed to determine the effect of administration of live OLB6378 on infants’ humoral immunity. Secondly, we tried to elucidate whether similar effects would be observed with administration of non-live OLB6378. Low birth weight (LBW) infants weighing 1500–2500 g were divided into three groups: Group N (no intervention), Group L (administered live OLB6378 concentrate), and Group H (administered non-live OLB6378 concentrate). The interventions were started within 48 h after birth and continued until six months of age. Serum immunoglobulin G (IgG) levels (IgG at one month/IgG at birth) were significantly higher in Group L than in Group N (p < 0.01). Group H exhibited significantly higher serum IgG levels (p < 0.01) at one month of age and significantly higher intestinal secretory immunoglobulin A (SIgA) levels (p < 0.05) at one and two months of age than Group N. No difference was observed in the mortality or morbidity between groups. Thus, OLB6378 administration in LBW infants enhanced humoral immunity, and non-live OLB6378, which is more useful as a food ingredient, showed a more marked effect than the viable bacteria. PMID:28245626

  15. Antimicrobial agent, tetracycline, enhanced upper alimentary tract Candida albicans infection and its related mucosal proliferation in alloxan-induced diabetic rats.

    PubMed

    Sano, Tomoya; Ozaki, Kiyokazu; Kodama, Yasushi; Matsuura, Tetsuro; Narama, Isao

    2012-10-01

    Alloxan-induced diabetic rats showed proliferative changes in the forestomach, accompanied by chronic inflammation, and one lesion progress to squamous cell carcinoma (SCC) without distant metastasis. The authors demonstrated that these lesions might be caused by Candida albicans infection. Antimicrobial therapy, particularly tetracycline treatment, has been blamed for a reduction in the number of competing bacterial organisms, which is frequently mentioned as a cause of candidiasis. The objective of this study is to ascertain whether or not tetracycline treatment can accelerate early-onset of C. albicans infection and the proliferative changes in this diabetic model. Alloxan-induced diabetic rats were given chlorinated water (AL group) and tetracycline solution (0.1% during week 1 and 0.01% thereafter) as drinking water (AT group). They were sacrificed after 25 weeks of drinking the treated water. The infection rate with C. albicans in the AT group was significantly higher than in the AL group. The incidence and severity of the squamous cell hyperplasia were enhanced in the AT group compared to the AL group. The proliferative lesions were consistently accompanied by inflammation and C. albicans infection in both groups. SCC was detected in one case in the AT group. These findings demonstrate that tetracycline induces C. albicans infection and enhances forestomach proliferative lesions in alloxan-induced diabetic rats.

  16. Enhancing stability of octahedral PtNi nanoparticles for oxygen reduction reaction by halide treatment

    NASA Astrophysics Data System (ADS)

    Choi, Juhyuk; Lee, Youhan; Kim, Jihan; Lee, Hyunjoo

    2016-03-01

    Because a reduction in the amount of Pt catalysts is essential for the commercialization of fuel cells, various approaches have been tested to maximize the mass activity of Pt-based catalysts. Among these, the most successful results so far were obtained using shaped PtNi alloy nanoparticles, preferably with PtNi(111) facets. However, these nanoparticles typically suffer from much lower activity after the durability tests due to the leaching out of the surface Ni during the oxygen reduction reaction (ORR), which leads to the disappearance of the activity-enhancing effect caused by electronic structure modification. Here, we showed that halide treatment of the octahedral PtNi nanoparticles could significantly enhance their durability. Halides are adsorbed on surface Ni more strongly than on surface Pt, and the surface halides are found to preserve the surface Ni that induces the ORR activity enhancement. Especially, Br can preserve the surface Ni effectively. Durability testing by repeating cyclic voltammetry 10,000 times in the 0.6-1.1 V range showed that the mass activity decreased by 52.6% for the as-prepared PtNi octahedral nanoparticles, whereas the mass activity decreased by only 15.0% for the Br-treated PtNi nanoparticles. The simple treatment significantly enhanced the long-term stability of the highly active PtNi alloy nano-octahedra.

  17. An Overview of Challenges Limiting the Design of Protective Mucosal Vaccines for Finfish

    PubMed Central

    Munang’andu, Hetron Mweemba; Mutoloki, Stephen; Evensen, Øystein

    2015-01-01

    Research in mucosal vaccination in finfish has gained prominence in the last decade in pursuit of mucosal vaccines that would lengthen the duration of protective immunity in vaccinated fish. However, injectable vaccines have continued to dominate in the vaccination of finfish because they are perceived to be more protective than mucosal vaccines. Therefore, it has become important to identify the factors that limit developing protective mucosal vaccines in finfish as an overture to identifying key areas that require optimization in mucosal vaccine design. Some of the factors that limit the success for designing protective mucosal vaccines for finfish identified in this review include the lack optimized protective antigen doses for mucosal vaccines, absence of immunostimulants able to enhance the performance of non-replicative mucosal vaccines, reduction of systemic antibodies due to prolonged exposure to oral vaccination and the lack of predefined correlates of protective immunity for use in the optimization of newly developed mucosal vaccines. This review also points out the need to develop prime-boost vaccination regimes able to induce long-term protective immunity in vaccinated fish. By overcoming some of the obstacles identified herein, it is anticipated that future mucosal vaccines shall be designed to induce long-term protective immunity in finfish. PMID:26557121

  18. Mucosal vaccines: the promise and the challenge.

    PubMed

    Neutra, Marian R; Kozlowski, Pamela A

    2006-02-01

    Most infectious agents enter the body at mucosal surfaces and therefore mucosal immune responses function as a first line of defence. Protective mucosal immune responses are most effectively induced by mucosal immunization through oral, nasal, rectal or vaginal routes, but the vast majority of vaccines in use today are administered by injection. As discussed in this Review, current research is providing new insights into the function of mucosal tissues and the interplay of innate and adaptive immune responses that results in immune protection at mucosal surfaces. These advances promise to accelerate the development and testing of new mucosal vaccines against many human diseases including HIV/AIDS.

  19. Resonant Enhancement of Nuclear Reactions as a Possible Solution to the Cosmological Lithium Problem

    NASA Astrophysics Data System (ADS)

    Cyburt, Richard H.; Pospelov, Maxim

    There is a significant discrepancy between the current theoretical prediction of the cosmological lithium abundance, mostly produced as 7Be during the Big Bang, and its observationally inferred value. We investigate whether the resonant enhancement of 7 Be burning reactions may alleviate this discrepancy. We identify one narrow nuclear level in 9B, E5/2+ ≃ 16.7 MeV that is not sufficiently studied experimentally, and being just ~ 200 keV above the 7Be+d threshold, may lead to the resonant enhancement of 7Be(d, γ)9B and 7Be(d, p)αα reactions. We determine the relationship between the domain of resonant energies Er and the deuterium separation width Γd that results in the significant depletion of the cosmological lithium abundance and find that (Er, Γd)≃(170-220, 10-40) keV can eliminate the current discrepancy. Such a large width at this resonant energy can be only achieved if the interaction radius for the deuterium entrance channel is very large, a27 ≥ 10 fm. New nuclear experimental and theoretical work is needed to clarify the role this resonance plays on the BBN prediction of the lithium abundance. Alternatively, the most liberal interpretation of the allowed parameters of 16.7 MeV resonance can significantly increase the errors in predicted lithium abundance: [7Li/H]BBN = (2.5-6) × 10-10.

  20. A combination of quantitative marinating and Maillard reaction to enhance volatile flavor in Chinese marinated chicken.

    PubMed

    Wei, Xiuli; Wang, Chunqing; Zhang, Chunhui; Li, Xia; Wang, Jinzhi; Li, Hai; Tang, Chunhong

    2017-02-01

    A combination of quantitative marinating and Maillard reaction was investigated by adding d-xylose, l-cysteine and thiamine to the marinated brine of quantitative marinating, which was expected to enhance the volatile flavor of Chinese marinated chicken. Response surface methodology was used to optimize parameters, in which response was sensory evaluation scores of marinated chicken. A Box-Behnken center design was applied to the optimized added contents. The optimized contents were d-xylose (1-5‰), l-cysteine (1-5‰) and thiamine (1-3‰). Analysis of variance indicated that a second-order polynomial equation could predict the experimental data well (R(2)  = 0.94), and sensory evaluation scores were significantly affected by the added amount of d-xylose, l-cysteine and thiamine. The optimal conditions that maximized the sensory evaluation score of Chinese marinated chicken were found to be 4.96‰ d-xylose, 2.28‰ l-cysteine and 2.66‰ thiamine (w/w). Given these optimal conditions, a number of meat-like flavor compounds such as 2-pentyl-furan, benzothiazole and 4-methyl-5-thiazoleethanol were identified by gas chromatographic-mass spectrometric analysis. Our results suggested that a combination of quantitative marinating and Maillard reaction might be a promising method to enhance the volatile flavor, especially meat-like flavor, of Chinese marinated chicken. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  1. Intrinsic relationship between enhanced oxygen reduction reaction activity and nanoscale work function of doped carbons.

    PubMed

    Cheon, Jae Yeong; Kim, Jong Hun; Kim, Jae Hyung; Goddeti, Kalyan C; Park, Jeong Young; Joo, Sang Hoon

    2014-06-25

    Nanostructured carbon materials doped with a variety of heteroatoms have shown promising electrocatalytic activity in the oxygen reduction reaction (ORR). However, understanding of the working principles that underpin the superior ORR activity observed with doped nanocarbons is still limited to predictions based on theoretical calculations. Herein, we demonstrate, for the first time, that the enhanced ORR activity in doped nanocarbons can be correlated with the variation in their nanoscale work function. A series of doped ordered mesoporous carbons (OMCs) were prepared using N, S, and O as dopants; the triple-doped, N,S,O-OMC displayed superior ORR activity and four-electron selectivity compared to the dual-doped (N,O-OMC and S,O-OMC) and the monodoped (O-OMC) OMCs. Significantly, the work functions of these heteroatom-doped OMCs, measured by Kelvin probe force microscopy, display a strong correlation with the activity and reaction kinetics for the ORR. This unprecedented experimental insight can be used to provide an explanation for the enhanced ORR activity of heteroatom-doped carbon materials.

  2. Prompt gamma ray diagnostics and enhanced hadron-therapy using neutron-free nuclear reactions

    NASA Astrophysics Data System (ADS)

    Giuffrida, L.; Margarone, D.; Cirrone, G. A. P.; Picciotto, A.; Cuttone, G.; Korn, G.

    2016-10-01

    We propose a series of simulations about the potential use of Boron isotopes to trigger neutron-free (aneutronic) nuclear reactions in cancer cells through the interaction with an incoming energetic proton beam, thus resulting in the emission of characteristic prompt gamma radiation (429 keV, 718 keV and 1435 keV). Furthermore assuming that the Boron isotopes are absorbed in cancer cells, the three alpha-particles produced in each p-11B aneutronic nuclear fusion reactions can potentially result in the enhancement of the biological dose absorbed in the tumor region since these multi-MeV alpha-particles are stopped inside the single cancer cell, thus allowing to spare the surrounding tissues. Although a similar approach based on the use of 11B nuclei has been proposed in [Yoon et al. Applied Physics Letters 105, 223507 (2014)], our work demonstrate, using Monte Carlo simulations, the crucial importance of the use of 10B nuclei (in a solution containing also 11B) for the generation of prompt gamma-rays, which can be applied to medical imaging. In fact, we demonstrate that the use of 10B nuclei can enhance the intensity of the 718 keV gamma-ray peak more than 30 times compared to the solution containing only 11B nuclei. A detailed explanation of the origin of the different prompt gamma-rays, as well as of their application as real-time diagnostics during a potential cancer treatment, is here discussed.

  3. Amorphous nickel boride membrane on a platinum-nickel alloy surface for enhanced oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    He, Daping; Zhang, Libo; He, Dongsheng; Zhou, Gang; Lin, Yue; Deng, Zhaoxiang; Hong, Xun; Wu, Yuen; Chen, Chen; Li, Yadong

    2016-08-01

    The low activity of the oxygen reduction reaction in polymer electrolyte membrane fuel cells is a major barrier for electrocatalysis, and hence needs to be optimized. Tuning the surface electronic structure of platinum-based bimetallic alloys, a promising oxygen reduction reaction catalyst, plays a key role in controlling its interaction with reactants, and thus affects the efficiency. Here we report that a dealloying process can be utilized to experimentally fabricate the interface between dealloyed platinum-nickel alloy and amorphous nickel boride membrane. The coating membrane works as an electron acceptor to tune the surface electronic structure of the platinum-nickel catalyst, and this composite catalyst composed of crystalline platinum-nickel covered by amorphous nickel boride achieves a 27-times enhancement in mass activity relative to commercial platinum/carbon at 0.9 V for the oxygen reduction reaction performance. Moreover, this interactional effect between a crystalline surface and amorphous membrane can be readily generalized to facilitate the 3-times higher catalytic activity of commercial platinum/carbon.

  4. Amorphous nickel boride membrane on a platinum–nickel alloy surface for enhanced oxygen reduction reaction

    PubMed Central

    He, Daping; Zhang, Libo; He, Dongsheng; Zhou, Gang; Lin, Yue; Deng, Zhaoxiang; Hong, Xun; Wu, Yuen; Chen, Chen; Li, Yadong

    2016-01-01

    The low activity of the oxygen reduction reaction in polymer electrolyte membrane fuel cells is a major barrier for electrocatalysis, and hence needs to be optimized. Tuning the surface electronic structure of platinum-based bimetallic alloys, a promising oxygen reduction reaction catalyst, plays a key role in controlling its interaction with reactants, and thus affects the efficiency. Here we report that a dealloying process can be utilized to experimentally fabricate the interface between dealloyed platinum–nickel alloy and amorphous nickel boride membrane. The coating membrane works as an electron acceptor to tune the surface electronic structure of the platinum–nickel catalyst, and this composite catalyst composed of crystalline platinum–nickel covered by amorphous nickel boride achieves a 27-times enhancement in mass activity relative to commercial platinum/carbon at 0.9 V for the oxygen reduction reaction performance. Moreover, this interactional effect between a crystalline surface and amorphous membrane can be readily generalized to facilitate the 3-times higher catalytic activity of commercial platinum/carbon. PMID:27503412

  5. Local administration of growth hormone enhances periimplant bone reaction in an osteoporotic rabbit model.

    PubMed

    Tresguerres, Isabel F; Clemente, Celia; Donado, Manuel; Gómez-Pellico, Luis; Blanco, Luis; Alobera, Miguel Angel; Tresguerres, Jesús A F

    2002-12-01

    The purpose of this study was to determine whether rhGH administered locally during the surgical placement of an implant, in the tibia of an osteoporotic rabbit model, would induce qualitative and quantitative differences in peri-implant bone reaction. Eight New Zealand rabbits were ovariectomized and fed with a low-calcium diet (with 0.07% of calcium) to induce osteoporosis. After 6 weeks, an experimental titanium sheet was inserted into the rabbit tibiae. The rabbits were randomly divided into two groups. The experimental group was treated with 4 IU of rhGH added locally into the ostectomy as a lyophilized powder and the control group was left without any treatment. After 2 weeks, animals were sacrificed, tibial sections were prepared and bone-titanium interface was examined at light microscopy, using Masson, hematoxylin-eosin and Pichrosirius stains. Light microscopic morphometry and densitometry were used to comparatively quantitate bone reaction. Local administration of rhGH during the surgical placement of titanium sheets on the tibiae of an osteoporotic rabbit model enhances periosteal and transcortical reaction and mineralization of osteoid 14 days later around titanium sheets, without increasing bone resorption.

  6. Plasmonic photocatalytic reactions enhanced by hot electrons in a one-dimensional quantum well

    NASA Astrophysics Data System (ADS)

    Huang, H. J.; Liu, B.-H.; Lin, C.-T.; Su, W. S.

    2015-11-01

    The plasmonic endothermic oxidation of ammonium ions in a spinning disk reactor resulted in light energy transformation through quantum hot charge carriers (QHC), or quantum hot electrons, during a chemical reaction. It is demonstrated with a simple model that light of various intensities enhance the chemical oxidization of ammonium ions in water. It was further observed that light illumination, which induces the formation of plasmons on a platinum (Pt) thin film, provided higher processing efficiency compared with the reaction on a bare glass disk. These induced plasmons generate quantum hot electrons with increasing momentum and energy in the one-dimensional quantum well of a Pt thin film. The energy carried by the quantum hot electrons provided the energy needed to catalyze the chemical reaction. The results indicate that one-dimensional confinement in spherical coordinates (i.e., nanoparticles) is not necessary to provide an extra excited state for QHC generation; an 8 nm Pt thin film for one-dimensional confinement in Cartesian coordinates can also provide the extra excited state for the generation of QHC.

  7. Plasmonic photocatalytic reactions enhanced by hot electrons in a one-dimensional quantum well

    SciTech Connect

    Huang, H. J. E-mail: hhjhuangkimo@gmail.com; Liu, B. H.; Lin, C. T.; Su, W. S.

    2015-11-15

    The plasmonic endothermic oxidation of ammonium ions in a spinning disk reactor resulted in light energy transformation through quantum hot charge carriers (QHC), or quantum hot electrons, during a chemical reaction. It is demonstrated with a simple model that light of various intensities enhance the chemical oxidization of ammonium ions in water. It was further observed that light illumination, which induces the formation of plasmons on a platinum (Pt) thin film, provided higher processing efficiency compared with the reaction on a bare glass disk. These induced plasmons generate quantum hot electrons with increasing momentum and energy in the one-dimensional quantum well of a Pt thin film. The energy carried by the quantum hot electrons provided the energy needed to catalyze the chemical reaction. The results indicate that one-dimensional confinement in spherical coordinates (i.e., nanoparticles) is not necessary to provide an extra excited state for QHC generation; an 8 nm Pt thin film for one-dimensional confinement in Cartesian coordinates can also provide the extra excited state for the generation of QHC.

  8. Differential Effect Triggered by a Heparan Mimetic of the RGTA Family Preventing Oral Mucositis Without Tumor Protection

    SciTech Connect

    Mangoni, Monica; Yue Xiaoli; Morin, Christophe; Violot, Dominique; Frascogna, Valerie; Tao Yungan; Opolon, Paule; Castaing, Marine; Auperin, Anne; Biti, Giampaolo; Barritault, Denis; Vozenin-Brotons, Marie-Catherine; Deutsch, Eric; Bourhis, Jean

    2009-07-15

    Purpose: Oral mucositis is a common side effect induced by radio/chemotherapy in patients with head and neck cancer. Although it dramatically impairs patient quality of life, no efficient and safe therapeutic solution is available today. Therefore, we investigated the protective efficacy of a new heparan mimetic biopolymer, RGTA-OTR4131, used alone or in combination with amifostine, for oral mucositis and simultaneously evaluated its effect on tumor growth in vitro and in vivo. Methods and Materials: A single dose of 16.5 Gy was selectively delivered to the snout of mice, and the effects of OTR4131 or amifostine-OTR4131 were analyzed by macroscopic scoring and histology. The effect of OTR4131 administration on tumor growth was then investigated in vitro and in xenograft models using two cell lines (HEP-2 and HT-29). Results: Amifostine and OTR4131 significantly decreased the severity and duration of lip mucosal reactions. However, amifostine has to be administered before irradiation, whereas the most impressive protection was obtained when OTR4131 was injected 24 h after irradiation. In addition, OTR4131 was well tolerated, and the combination of amifostine and OTR4131 further enhanced mucosal protection. At the tumor level, OTR4131 did not modify HEP-2 cell line clonogenic survival in vitro or protect xenografted tumor cells from radiotherapy. Of interest, high doses of OTR4131 significantly decreased clonogenic survival of HT-29 cells. Conclusions: RGTAs-OTR4131 is a well-tolerated, natural agent that effectively reduces radio-induced mucositis without affecting tumor sensitivity to irradiation. This suggests a possible transfer into the clinic for patients' benefit.

  9. Realistic neutron energy spectrum and a possible enhancement of reaction rates in the early Universe plasma

    NASA Astrophysics Data System (ADS)

    Nakao, Yasuyuki; Tsukida, Kazuki; Voronchev, Victor T.

    2011-09-01

    A plasma-kinetic model to properly describe the behavior of neutrons in the primordial plasma during the epoch of big bang nucleosynthesis (BBN) is formulated. For the first time, this model is applied to calculate the realistic energy distribution function of these neutrons and examine their main characteristics. The fact that the realistic neutron distribution departs from a conventional Maxwellian function is obtained; its high-energy tail is essentially enhanced by nonthermal neutrons produced in the T(d,n)4He and D(d,n)3He reactions. The fraction of these neutrons ηn' in the total neutron component is at a level of 10-2%-10-3%, while their effective temperature Tn' reaches several MeV and exceeds the plasma temperature in the BBN epoch by about a factor of 102. The nonthermal neutron influence on individual reactions is examined on the example of the threshold D(n,2n)p, Li7(n,nt)He4, and Be7(n,nHe3)He4 processes. We show that at plasma temperatures T9≲1.2 the nonthermal neutrons strongly maintain these reactions, increasing their rates by orders of magnitude as compared with the respective Maxwellian estimates. Note that the obtained phenomenon has a general nature. It may manifest in other nuclear systems and becomes a natural supplement of nonthermal effects triggered by dark matter decay, which has been extensively studied elsewhere. An important question remains—to what extent such fast particles may affect chain reaction kinetics in the plasma and change the predictions of standard BBN.

  10. Intervertebral reaction force prediction using an enhanced assembly of OpenSim models.

    PubMed

    Senteler, Marco; Weisse, Bernhard; Rothenfluh, Dominique A; Snedeker, Jess G

    2016-01-01

    OpenSim offers a valuable approach to investigating otherwise difficult to assess yet important biomechanical parameters such as joint reaction forces. Although the range of available models in the public repository is continually increasing, there currently exists no OpenSim model for the computation of intervertebral joint reactions during flexion and lifting tasks. The current work combines and improves elements of existing models to develop an enhanced model of the upper body and lumbar spine. Models of the upper body with extremities, neck and head were combined with an improved version of a lumbar spine from the model repository. Translational motion was enabled for each lumbar vertebrae with six controllable degrees of freedom. Motion segment stiffness was implemented at lumbar levels and mass properties were assigned throughout the model. Moreover, body coordinate frames of the spine were modified to allow straightforward variation of sagittal alignment and to simplify interpretation of results. Evaluation of model predictions for level L1-L2, L3-L4 and L4-L5 in various postures of forward flexion and moderate lifting (8 kg) revealed an agreement within 10% to experimental studies and model-based computational analyses. However, in an extended posture or during lifting of heavier loads (20 kg), computed joint reactions differed substantially from reported in vivo measures using instrumented implants. We conclude that agreement between the model and available experimental data was good in view of limitations of both the model and the validation datasets. The presented model is useful in that it permits computation of realistic lumbar spine joint reaction forces during flexion and moderate lifting tasks. The model and corresponding documentation are now available in the online OpenSim repository.

  11. Enhancement of oxygen reduction reaction activities by Pt nanoclusters decorated on ordered mesoporous porphyrinic carbons

    SciTech Connect

    Sun-Mi Hwang; Choi, YongMan; Kim, Min Gyu; Sohn, Young-Jun; Cheon, Jae Yeong; Joo, Sang Hoon; Yim, Sung-Dae; Kuttiyiel, Kurian A.; Sasaki, Kotaro; Adzic, Radoslav R.; Park, Gu-Gon

    2016-03-08

    The high cost of Pt-based membrane electrode assemblies (MEAs) is a critical hurdle for the commercialization of polymer electrolyte fuel cells (PEFCs). Recently, non-precious metal-based catalysts (NPMCs) have demonstrated much enhanced activity but their oxygen reduction reaction (ORR) activity is still inferior to that of Pt-based catalysts resulting in a much thicker electrode in the MEA. For the reduction of mass transport and ohmic overpotential we adopted a new concept of catalyst that combines an ultra-low amount of Pt nanoclusters with metal–nitrogen (M–Nx) doped ordered mesoporous porphyrinic carbon (FeCo–OMPC(L)). The 5 wt% Pt/FeCo–OMPC(L) showed a 2-fold enhancement in activities compared to a higher loading of Pt. Our experimental results supported by first-principles calculations indicate that a trace amount of Pt nanoclusters on FeCo–OMPC(L) significantly enhances the ORR activity due to their electronic effect as well as geometric effect from the reduced active sites. Finally, in terms of fuel cell commercialization, this class of catalysts is a promising candidate due to the limited use of Pt in the MEA.

  12. Enhancement of oxygen reduction reaction activities by Pt nanoclusters decorated on ordered mesoporous porphyrinic carbons

    DOE PAGES

    Sun-Mi Hwang; Choi, YongMan; Kim, Min Gyu; ...

    2016-03-08

    The high cost of Pt-based membrane electrode assemblies (MEAs) is a critical hurdle for the commercialization of polymer electrolyte fuel cells (PEFCs). Recently, non-precious metal-based catalysts (NPMCs) have demonstrated much enhanced activity but their oxygen reduction reaction (ORR) activity is still inferior to that of Pt-based catalysts resulting in a much thicker electrode in the MEA. For the reduction of mass transport and ohmic overpotential we adopted a new concept of catalyst that combines an ultra-low amount of Pt nanoclusters with metal–nitrogen (M–Nx) doped ordered mesoporous porphyrinic carbon (FeCo–OMPC(L)). The 5 wt% Pt/FeCo–OMPC(L) showed a 2-fold enhancement in activities comparedmore » to a higher loading of Pt. Our experimental results supported by first-principles calculations indicate that a trace amount of Pt nanoclusters on FeCo–OMPC(L) significantly enhances the ORR activity due to their electronic effect as well as geometric effect from the reduced active sites. Finally, in terms of fuel cell commercialization, this class of catalysts is a promising candidate due to the limited use of Pt in the MEA.« less

  13. Exploration of the Role of Heat Activation in Enhancing Serpentine Carbon Sequestration Reactions

    SciTech Connect

    McKelvy, M.J.; Chizmeshya, A.V.G.; Diefenbacher, J.; Bearat, H.; Wolf, G.

    2005-03-29

    As compared with other candidate carbon sequestration technologies, mineral carbonation offers the unique advantage of permanent disposal via geologically stable and environmentally benign carbonates. The primary challenge is the development of an economically viable process. Enhancing feedstock carbonation reactivity is key. Heat activation dramatically enhances aqueous serpentine carbonation reactivity. Although the present process is too expensive to implement, the materials characteristics and mechanisms that enhance carbonation are of keen interest for further reducing cost. Simultaneous thermogravimetric and differential thermal analysis (TGA/DTA) of the serpentine mineral lizardite was used to isolate a series of heat-activated materials as a function of residual hydroxide content at progressively higher temperatures. Their structure and composition are evaluated via TGA/DTA, X-ray powder diffraction (including phase analysis), and infrared analysis. The meta-serpentine materials that were observed to form ranged from those with longer range ordering, consistent with diffuse stage-2 like interlamellar order, to an amorphous component that preferentially forms at higher temperatures. The aqueous carbonation reaction process was investigated for representative materials via in situ synchrotron X-ray diffraction. Magnesite was observed to form directly at 15 MPa CO{sub 2} and at temperatures ranging from 100 to 125 C. Carbonation reactivity is generally correlated with the extent of meta-serpentine formation and structural disorder.

  14. Airway structural cells regulate TLR5-mediated mucosal adjuvant activity.

    PubMed

    Van Maele, L; Fougeron, D; Janot, L; Didierlaurent, A; Cayet, D; Tabareau, J; Rumbo, M; Corvo-Chamaillard, S; Boulenouar, S; Jeffs, S; Vande Walle, L; Lamkanfi, M; Lemoine, Y; Erard, F; Hot, D; Hussell, T; Ryffel, B; Benecke, A G; Sirard, J-C

    2014-05-01

    Antigen-presenting cell (APC) activation is enhanced by vaccine adjuvants. Most vaccines are based on the assumption that adjuvant activity of Toll-like receptor (TLR) agonists depends on direct, functional activation of APCs. Here, we sought to establish whether TLR stimulation in non-hematopoietic cells contributes to flagellin's mucosal adjuvant activity. Nasal administration of flagellin enhanced T-cell-mediated immunity, and systemic and secretory antibody responses to coadministered antigens in a TLR5-dependent manner. Mucosal adjuvant activity was not affected by either abrogation of TLR5 signaling in hematopoietic cells or the presence of flagellin-specific, circulating neutralizing antibodies. We found that flagellin is rapidly degraded in conducting airways, does not translocate into lung parenchyma and stimulates an early immune response, suggesting that TLR5 signaling is regionalized. The flagellin-specific early response of lung was regulated by radioresistant cells expressing TLR5 (particularly the airway epithelial cells). Flagellin stimulated the epithelial production of a small set of mediators that included the chemokine CCL20, which is known to promote APC recruitment in mucosal tissues. Our data suggest that (i) the adjuvant activity of TLR agonists in mucosal vaccination may require TLR stimulation of structural cells and (ii) harnessing the effect of adjuvants on epithelial cells can improve mucosal vaccines.

  15. Reaction enhancement in an unsteady obstacle wake: Implications for broadcast spawning and other mixing-limited processes in marine environments

    NASA Astrophysics Data System (ADS)

    Crimaldi, J. P.; Kawakami, T. R.

    2015-03-01

    Structured wakes behind flow obstacles are shown to be regions that enhance mixing and reactions between initially distant scalars, with implications for a wide range of mixing-limited biogeochemical processes in marine systems (e.g., broadcast spawning, phytoplankton-nutrient interactions). Reaction of initially distant reactive scalars in the structured laminar wake of a round obstacle is quantified using direct numerical simulations of the 2D Navier-Stokes and reactive transport equations with Reynolds number of 100 and Schmidt number of 1. Scalars are released upstream of the obstacle, initially separated by ambient fluid that acts as a barrier to mixing and reaction. Reaction is computed using second-order kinetics in the low-Damkholer limit. Reaction enhancement is quantified by comparing the obstacle-wake reactions to those in a similar flow but without the obstacle. Integrated reaction rates are shown to be orders of magnitude larger in the obstacle wake for cases with significant initial separation between the scalars. The role of unsteady processes in the reaction enhancement is also investigated by quantifying the scalar covariance in different regions of the wake.

  16. Immunomodulation by mucosal gene transfer using TGF-beta DNA.

    PubMed Central

    Kuklin, N A; Daheshia, M; Chun, S; Rouse, B T

    1998-01-01

    This report evaluates the efficacy of DNA encoding TGF-beta administered mucosally to suppress immunity and modulate the immunoinflammatory response to herpes simplex virus (HSV) infection. A single intranasal administration of an eukaryotic expression vector encoding TGF-beta1 led to expression in the lung and lymphoid tissue. T cell-mediated immune responses to HSV infection were suppressed with this effect persisting as measured by the delayed-type hypersensitivity reaction for at least 7 wk. Treated animals were more susceptible to systemic infection with HSV. Multiple prophylactic mucosal administrations of TGF-beta DNA also suppressed the severity of ocular lesions caused by HSV infection, although no effects on this immunoinflammatory response were evident after therapeutic treatment with TGF-beta DNA. Our results demonstrate that the direct mucosal gene transfer of immunomodulatory cytokines provides a convenient means of modulating immunity and influencing the expression of inflammatory disorders. PMID:9664086

  17. Enhanced Specificity of Multiplex Polymerase Chain Reaction via CdTe Quantum Dots

    NASA Astrophysics Data System (ADS)

    Liang, Gaofeng; Ma, Chao; Zhu, Yanliang; Li, Shuchun; Shao, Youhua; Wang, Yong; Xiao, Zhongdang

    2011-12-01

    Nanoparticles were recently reported to be able to improve both efficiency and specificity in polymerase chain reaction (PCR). Here, CdTe QDs were introduced into multi-PCR systems. It was found that an appropriate concentration of CdTe QDs could enhance the performance of multi-PCR by reducing the formation of nonspecific products in the complex system, but an excessive amount of CdTe QDs could suppress the PCR. The effects of QDs on PCR can be reversed by increasing the polymerase concentration or by adding bovine serum albumin (BSA). The mechanisms underlying these effects were also discussed. The results indicated that CdTe QDs could be used to optimize the amplification products of the PCR, especially in the multi-PCR system with different primers annealing temperatures, which is of great significance for molecular diagnosis.

  18. Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide

    NASA Astrophysics Data System (ADS)

    Fang, Si-Ling; Chou, Tsu-Chin; Samireddi, Satyanarayana; Chen, Kuei-Hsien; Chen, Li-Chyong; Chen, Wei-Fu

    2017-03-01

    Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP2 crystal phase is formed which enhances the electrochemical activity.

  19. Complex dynamics and enhanced photosensitivity in a modified Belousov-Zhabotinsky reaction.

    PubMed

    Li, Nan; Zhao, Jinpei; Wang, Jichang

    2008-06-28

    This study presents an experimental investigation of nonlinear dynamics in a modified Belousov-Zhabotinsky (BZ) reaction, in which the addition of 1,4-benzoquinone induced various complex behaviors such as mixed-mode oscillations and consecutive period-adding bifurcations. In addition, the presence of 1,4-benzoquinone significantly enhanced the photosensitivity of the ferroin-catalyzed BZ system, in which light-induced transitions between simple and complex oscillations have been achieved. Mechanistic study suggests that the influence of benzoquinone may arise from its interactions with the metal catalyst ferroin/ferriin, where cyclic voltammograms illustrate that the presence of benzoquinone causes an increase in the redox potential of ferroin/ferriin couple, which may consequently alternate the oxidation and reduction paths of the catalyst.

  20. Complex dynamics and enhanced photosensitivity in a modified Belousov-Zhabotinsky reaction

    SciTech Connect

    Li Nan; Zhao Jinpei; Wang Jichang

    2008-06-28

    This study presents an experimental investigation of nonlinear dynamics in a modified Belousov-Zhabotinsky (BZ) reaction, in which the addition of 1,4-benzoquinone induced various complex behaviors such as mixed-mode oscillations and consecutive period-adding bifurcations. In addition, the presence of 1,4-benzoquinone significantly enhanced the photosensitivity of the ferroin-catalyzed BZ system, in which light-induced transitions between simple and complex oscillations have been achieved. Mechanistic study suggests that the influence of benzoquinone may arise from its interactions with the metal catalyst ferroin/ferriin, where cyclic voltammograms illustrate that the presence of benzoquinone causes an increase in the redox potential of ferroin/ferriin couple, which may consequently alternate the oxidation and reduction paths of the catalyst.

  1. Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide

    PubMed Central

    Fang, Si-Ling; Chou, Tsu-Chin; Samireddi, Satyanarayana; Chen, Kuei-Hsien; Chen, Li-Chyong

    2017-01-01

    Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer–Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP2 crystal phase is formed which enhances the electrochemical activity. PMID:28405392

  2. Complex dynamics and enhanced photosensitivity in a modified Belousov-Zhabotinsky reaction

    NASA Astrophysics Data System (ADS)

    Li, Nan; Zhao, Jinpei; Wang, Jichang

    2008-06-01

    This study presents an experimental investigation of nonlinear dynamics in a modified Belousov-Zhabotinsky (BZ) reaction, in which the addition of 1,4-benzoquinone induced various complex behaviors such as mixed-mode oscillations and consecutive period-adding bifurcations. In addition, the presence of 1,4-benzoquinone significantly enhanced the photosensitivity of the ferroin-catalyzed BZ system, in which light-induced transitions between simple and complex oscillations have been achieved. Mechanistic study suggests that the influence of benzoquinone may arise from its interactions with the metal catalyst ferroin/ferriin, where cyclic voltammograms illustrate that the presence of benzoquinone causes an increase in the redox potential of ferroin/ferriin couple, which may consequently alternate the oxidation and reduction paths of the catalyst.

  3. Atomic Ordering Enhanced Electrocatalytic Activity of Nanoalloys for Oxygen Reduction Reaction

    SciTech Connect

    Loukrakpam, Rameshwori; Shan, Shiyao; Petkov, Valeri; Yang, Lefu; Luo, Jin; Zhong, Chuan-Jian

    2013-10-01

    For oxygen reduction reaction (ORR) over alloy electrocatalysts, the understanding of how the atomic arrangement of the metal species in the nanocatalysts is responsible for the catalytic enhancement is challenging for achieving better design and tailoring of nanoalloy catalysts. This paper reports results of an investigation of the atomic structures and the electrocatalytic activities of ternary and binary nanoalloys, aiming at revealing a fundamental insight into the unique atomic-scale structure-electrocatalytic activity relationship. PtIrCo catalyst and its binary counterparts (PtCo and PtIr) are chosen as a model system for this study. The effect of thermochemical treatment temperature on the atomic-scale structure of the catalysts was examined as a useful probe to the structure-activity correlation. The structural characterization of the binary and ternary nanoalloy catalysts was performed by combining surface sensitive techniques such as XPS and 3D atomic ordering sensitive techniques such as high-energy X-ray diffraction (HE-XRD) coupled to atomic pair distribution function (PDF) analysis (HE-XRD/PDFs) and computer simulations. The results show that the thermal treatment temperature tunes the nanoalloy’s atomic and chemical ordering in a different way depending on the chemical composition, leading to differences in the nanoalloy’s mass and specific activities. A unique structural tunability of the atomic ordering in a platinum-iridium-cobalt nanoalloy has been revealed for enhancing greatly the electrocatalytic activity toward oxygen reduction reaction, which has significant implication for rational design and nanoengineering of advanced catalysts for electrochemical energy conversion and storage.

  4. Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

    NASA Astrophysics Data System (ADS)

    Nouralishahi, Amideddin; Rashidi, Ali Morad; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Choolaei, Mohammadmehdi

    2015-04-01

    The electro-catalytic behavior of Pt-CoOx/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH4 as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoOx, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of COads on Pt active sites by the participation of CoOx. Compared to Pt/MWCNTs, Pt-CoOx/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoOx/MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups controls the total rate of MOR process.

  5. Aldimine Formation Reaction, the First Step of the Maillard Early-phase Reaction, Might be Enhanced in Variant Hemoglobin, Hb Himeji.

    PubMed

    Koga, Masafumi; Inada, Shinya; Shimizu, Sayoko; Hatazaki, Masahiro; Umayahara, Yutaka; Nishihara, Eijun

    2015-01-01

    Hb Himeji (β140Ala→Asp) is known as a variant hemoglobin in which glycation is enhanced and HbA1c measured by immunoassay shows a high value. The phenomenon of enhanced glycation in Hb Himeji is based on the fact that the glycation product of variant hemoglobin (HbX1c) shows a higher value than HbA1c. In this study, we investigated whether aldimine formation reaction, the first step of the Maillard early-phase reaction, is enhanced in Hb Himeji in vitro. Three non-diabetic subjects with Hb Himeji and four non-diabetic subjects without variant hemoglobin were enrolled. In order to examine aldimine formation reaction, whole blood cells were incubated with 500 mg/dl of glucose at 37°C for 1 hour and were analyzed by high-performance liquid chromatography. Both HbA1c and HbX1c were not increased in this condition. After incubation with glucose, labile HbA1c (LA1c) fraction increased in the controls (1.1±0.3%). In subjects with Hb Himeji increases in the labile HbX1c (LX1c) fraction as well as the LA1c fraction were observed, and the degree of increase in the LX1c fraction was significantly higher than that of the LA1c fraction (1.8±0.1% vs. 0.5±0.2%, P<0.01). We have shown for the first time that aldimine (LX1c) formation reaction might be enhanced in Hb Himeji in vitro. The 140th amino acid in β chain of hemoglobin is suggested to be involved in aldimine formation reaction.

  6. Enhanced Hydrogen Evolution Reactions on Nanostructured Cu2ZnSnS4 (CZTS) Electrocatalyst

    NASA Astrophysics Data System (ADS)

    Digraskar, Renuka V.; Mulik, Balaji B.; Walke, Pravin S.; Ghule, Anil V.; Sathe, Bhaskar R.

    2017-08-01

    A novel and facile one-step sonochemical method is used to synthesize Cu2ZnSnS4 (CZTS) nanoparticles (2.6 ± 0.4 nm) as cathode electrocatalyst for hydrogen evolution reactions. The detailed morphology, crystal and surface structure, and composition of the CZTS nanostructures were characterized by high resolution transmission electron microscopy (HR-TEM), Selected area electron diffraction (SAED), X-ray diffraction, Raman spectroscopy, FTIR analysis, Brunauer-Emmett-Teller (BET) surface area measurements, Electron dispersive analysis, X-ray photoelectron spectroscopy respectively. Electrocatalytic abilities of the nanoparticles toward Hydrogen Evolution Reactions (HER) were verified through cyclic voltammograms (CV) and Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements. It reveals enhanced activity at lower onset potential 300 mV v/s RHE, achieved at exceptionally high current density -130 mA/cm2, which is higher than the existing non-nobel metal based cathodes. Further result exhibits Tafel slope of 85 mV/dec, exchange current density of 882 mA/cm2, excellent stability (> 500 cycles) and lower charge transfer resistance. This sonochemically fabricated CZTSs nanoparticles are leading to significantly reduce cell cost and simplification of preparation process over existing high efficiency Pt and other nobel metal-free cathode electrocatalyst.

  7. Surface plasmon field-enhanced fluorescence spectroscopy studies of primer extension reactions.

    PubMed

    Stengel, Gudrun; Knoll, Wolfgang

    2005-04-22

    Surface plasmon field-enhanced fluorescence spectroscopy (SPFS) utilizes the evanescent electromagnetic field of a surface plasmon to excite chromophors in close proximity to the surface. While conventional surface plasmon resonance spectroscopy allows the observation of surface reactions by means of refractive index changes, SPFS additionally provides a channel for the read-out of fluorescence changes. Thus, the detection limit for low mass compounds, whose adsorption is only accompanied by small refractive index changes, can be substantially improved by fluorescent labeling. In this study, we present the first example that utilizes SPFS to follow the dynamics of an enzymatic reaction. The elongation of surface-tethered DNA has been observed by the incorporation of Cy5-labeled nucleotides into the nascent strand by the action of DNA polymerase I (Klenow fragment). The technique offers a rapid way to determine the binding constant and the catalytic activity of a DNA processing enzyme, here exemplified by the Klenow fragment. Furthermore, the effect of mispaired bases in the primer/template duplex and the influence of different label densities have been studied. The resulting sensitivity for nucleotide incorporation, being in the femtomolar regime, combined with the specificity of the enzyme for fully complementary DNA duplexes suggest the application of this assay as a powerful tool for DNA detection.

  8. Sorption enhanced reaction process for production of hydrogen. Phase 1 final report

    SciTech Connect

    Mayorga, S.G.; Hufton, J.R.; Sircar, S.; Gaffney, T.R.

    1997-07-01

    Hydrogen is one of the most suitable energy sources from both technological and environmental perspectives for the next century, especially in the context of a sustainable global energy economy. The most common industrial process to produce high-purity (99.99+ mol%) hydrogen is to reform natural gas by a catalytic reaction with steam at a high temperature. Conventional steam-methane reforming (SMR) contributed to approximately 2.4 billion standard cubic feet per day (SCFD) of hydrogen production in the US. By 1998, the growth of SMR-produced hydrogen in the US is expected to reach 3.4 billion SCFD, with the increased demand attributed to hydrogen`s use in reformulated gasolines required by the Clean Air Act. The goal of this work is to develop an even more efficient process for reforming steam and methane to hydrogen product than the conventional SMR process. The application of Sorption Enhanced Reaction (SER) technology to SMR has the potential to markedly reduce the cost of hydrogen through lower capital and energy requirements. The development of a more cost-effective route to hydrogen production based on natural gas as the primary energy source will accelerate the transition to a more hydrogen-based economy in the future. The paper describes the process, which includes a sorbent for CO{sub 2} removal, and the various tasks involved in its development.

  9. Enhancement of Au Dissolution by Microorganisms Using an Accelerating Cathode Reaction

    NASA Astrophysics Data System (ADS)

    Kita, Yoshito; Nishikawa, Hiroshi; Ike, Michihiko; Takemoto, Tadashi

    2009-02-01

    A Chromobacterium violaceum ( C. violaceum) strain that produces cyanide was used to dissolve Au. In this bacterial Au dissolution process, decreased dissolved oxygen concentration in the bacterial medium significantly inhibits Au dissolution. Although aeration is effective in increasing the level of dissolved oxygen in the bacterial medium, it is not effective in increasing Au dissolution during the growth phase of the bacteria because of the latter’s high respiratory consumption of oxygen. The present study investigated the utility of H2O2, rather than aeration, for increasing dissolved oxygen concentrations in bacterial growth medium. It was anticipated that the stronger oxidation reagent would increase Au dissolution by accelerating the cathode reaction during the bacterial growth phase. In fact, the addition of H2O2 to the bacterial culture increased dissolved oxygen concentrations in the growth phase and also drastically increased the dissolution rate of Au. Electrochemical measurements indicated that H2O2 addition to the bacterial medium accelerated the cathode reaction and thus enhanced Au dissolution by this biological process.

  10. Omics in fish mucosal immunity.

    PubMed

    Salinas, Irene; Magadán, Susana

    2017-10-01

    The mucosal immune system of fish is a complex network of immune cells and molecules that are constantly surveilling the environment and protecting the host from infection. A number of "omics" tools are now available and utilized to understand the complexity of mucosal immune systems in non-traditional animal models. This review summarizes recent advances in the implementation of "omics" tools pertaining to the four mucosa-associated lymphoid tissues in teleosts. Genomics, transcriptomics, proteomics, and "omics" in microbiome research require interdisciplinary collaboration and careful experimental design. The data-rich datasets generated are proving really useful at discovering new innate immune players in fish mucosal secretions, identifying novel markers of specific mucosal immune responses, unraveling the diversity of the B and T cell repertoires and characterizing the diversity of the microbial communities present in teleost mucosal surfaces. Bioinformatics, data analysis and storage platforms should be developed to facilitate rapid processing of large datasets, especially when mammalian tools such as bioinformatics analysis software are not available in fishes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Mucosal barrier injury, fever and infection in neutropenic patients with cancer: introducing the paradigm febrile mucositis.

    PubMed

    van der Velden, Walter J F M; Herbers, Alexandra H E; Netea, Mihai G; Blijlevens, Nicole M A

    2014-11-01

    Infection remains one of the most prominent complications after cytotoxic treatment for cancer. The connection between neutropenia and both infections and fever has long been designated as 'febrile neutropenia', but treatment with antimicrobial agents and haematopoietic growth factors has failed to significantly reduce its incidence. Moreover, emerging antimicrobial resistance is becoming a concern that necessitates the judicious use of available antimicrobial agents. In addition to neutropenia, patients who receive cytotoxic therapy experience mucosal barrier injury (MBI) or 'mucositis'. MBI creates a port-de-entrée for resident micro-organisms to cause blood stream infections and contributes directly to the occurrence of fever by disrupting the highly regulated host-microbe interactions, which, even in the absence of an infection, can result in strong inflammatory reactions. Indeed, MBI has been shown to be a pivotal factor in the occurrence of inflammatory complications after cytotoxic therapy. Hence, the concept 'febrile neutropenia' alone may no longer suffice and a new concept 'febrile mucositis' should be recognized as the two are at least complementary. This review we summarizes the existing evidence for both paradigms and proposes new therapeutic approaches to tackle the perturbed host-microbe interactions arising from cytotoxic therapy-induced tissue damage in order to reduce fever in neutropenic patients with cancer. © 2014 John Wiley & Sons Ltd.

  12. Enhancing oxygen reduction reaction activity of Pt-shelled catalysts via subsurface alloying.

    PubMed

    Cheng, Daojian; Qiu, Xiangguo; Yu, Haiyan

    2014-10-14

    Despite remarkable efforts have been put into the field of Pt-shelled catalysts containing an atomically thin Pt surface layer for the oxygen reduction reaction (ORR) in the last decade, further development of new Pt-shelled catalysts is still necessary. Here, a new set of Pt-shelled catalysts by subsurface alloying with early transition metals such as Mn and Fe is predicted to be a good candidate for the ORR by using density functional theory (DFT) calculations. Trends in oxygen reduction activity of Pt-alloy catalysts are determined with calculations of oxygen binding by using the slab and cluster models. It is found that the subsurface alloys by the incorporation of submonolayer M (M = Mn and Fe) into Pt(111) in the slab model result in the enhancement of ORR activity, compared with the well-known Pt(111)-skin-M, pure Pt, and Pt3M alloy catalysts. For the cluster model, the Pt12Mn and Pt12Fe clusters are also found to be the optimal catalysts for the ORR. It is expected that this work can open up new opportunities for enhancing the ORR activity of Pt-alloy catalysts by subsurface alloying.

  13. Functional palladium tetrapod core of heterogeneous palladium-platinum nanodendrites for enhanced oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Nguyen, Trung-Thanh; Pan, Chun-Jern; Liu, Jyong-Yue; Chou, Hung-Lung; Rick, John; Su, Wei-Nien; Hwang, Bing-Joe

    2014-04-01

    The synthesis, characterization, and application of bimetallic Pd-Pt nanocatalysts with heterogeneous structures are reported. The Pd tetrapod core is demonstrated to enhance the catalytic activity and durability of Pd@Pt nanodendrites for the oxygen reduction reaction (ORR). Special attention is given to the effects of oxalate-ion-formaldehyde during the hydrothermal synthesis of various Pd morphologies at different temperatures. Pd tetrapod synthesis can be delicately achieved without directly using hazardous CO gas. 30 wt% Pt on tetrapodal and truncated-octahedral Pd cores and 50 wt% Pt on tetrapodal Pd cores are prepared and compared against the commercial Pt/C catalyst (E-Tek) for ORR. The Pdtetrapod@30 wt% Pt catalyst exhibits the highest ORR activity. Overall, the Pd tetrapod core is a functional morphology which offers high-index facets for the subsequent deposition of Pt(110) nanodendrites, with the bimetallic interaction between two materials allowing for good electron transfer from the Pd core onto the Pt surfaces. Both effects contribute to the increased catalytic activity of Pdtetrapod@30 wt% Pt, even under a lower loading of Pt. Furthermore, Pdtetrapod@30 wt% Pt has a rather large particle size (∼39.5 nm) which enhances durability and resistance to the agglomeration of Pt.

  14. Enhancement of the contact hypersensitivity reaction by acute morphine administration at the elicitation phase.

    PubMed

    Nelson, C J; How, T; Lysle, D T

    1999-11-01

    The present study investigated the effects of morphine on the irritant contact sensitivity (ICS) and contact hypersensitivity (CHS) reaction. ICS was induced by croton oil application on the pinnae of naïve rats. Morphine injected prior to croton oil application did not affect the ICS response when assessed by measurements of pinnae thickness. CHS was induced by applying the antigen 2,4-dinitro-1-fluorobenzene (DNFB) to the pinnae of rats sensitized to DNFB. Rats received an injection of morphine prior to either initial antigen exposure (sensitization) or antigen reexposure (challenge). Morphine prior to challenge, but not sensitization, resulted in a pronounced enhancement of the CHS response as measured by pinna thickness. Quantitative PCR also showed increased IFN-gamma mRNA levels in the inflamed tissue of morphine-treated rats. Naltrexone blocked the morphine-induced enhancement of the CHS response. The differential effects of morphine suggest that opioids have a more pronounced effect on in vivo immune responses that involve immunological memory. Copyright 1999 Academic Press.

  15. Helminths and mucosal immune modulation.

    PubMed

    Weinstock, Joel V

    2006-08-01

    Geographic and ethnic variations in ulcerative colitis and Crohn's disease frequency suggest that environmental factors affect disease risk. Prevention of parasitic worms (helminths) through improved hygiene may be one factor leading to the increased disease prevalence. Helminths alter host mucosal and systemic immunity. Animals exposed to helminths are protected from experimental colitis and other immunological diseases, and helminthic colonization can be used to treat ongoing murine and human disease. Helminths induce mucosal T cells to make Th2 and regulatory cytokines. Helminth-induced mucosal IL4, TGFbeta, and IL10 likely are part of the protective process. Helminths affect pathways of innate immunity like TLR4 expression and function. Worms also induce various regulatory-type T-cell subsets in the gut that limit effector T-cell growth and function. These effects of once ever-present helminths may have protected people from immune-mediated illnesses like inflammatory bowel disease.

  16. Dispersion quality of amine functionalized multiwall carbon nanotubes plays critical roles in polymerase chain reaction enhancement

    NASA Astrophysics Data System (ADS)

    Yuce, Meral; Budak, Hikmet

    2014-12-01

    Impact of dispersion quality of NH2-MWCNTs (13-18 nm in diameter with a length between 1 and 12 µm, >99 % purity) in the amplification efficiency of a random DNA oligonucleotide library (96 bp) was investigated. Amplification yield in the presence of non-filtered NH2-MWCNT dispersion, filtered NH2-MWCNT dispersion and surface-attached NH2-MWCNTs was explored, and physical interactions between NH2-MWCNTs and major PCR reagents including DNA template, wild type Taq DNA polymerase enzyme and primers were determined using high resolution polyacrylamide gel electrophoresis, dynamic light scattering, UV-Vis-NIR spectroscopy and scanning electron microscopy techniques. The results revealed that presence of NH2-MWCNT dispersion which was sonicated, centrifuged and filtered, enhanced the total PCR efficiency up to 70 % while the presence of NH2-MWCNT only centrifuged after sonication, inhibited the reaction significantly at similar concentrations. Furthermore, the NH2-MWCNTs coupled covalently onto magnetic microspheres, contributed for the specificity enhancement whilst decreasing the amplification efficiency by 30 % at the maximum concentration, which suggests a removable enhancement system for sensitive applications. On the other hand, the relative hydrodynamic size distribution measurements displayed a clear difference between the filtered NH2 and non-filtered NH2-MWCNT water dispersions, which justifies the inhibition of the amplification by the non-filtered NH2-MWCNTs containing big agglomerates and bundles. Finally, we demonstrated that major PCR components adsorb onto the NH2-MWCNTs with diverse affinities, and maintain their functions after adsorption, which provides a good framework to further develop tunable NH2-MWCNT-carriers to be utilized in various nanobiotechnology and material science applications.

  17. Physiology and immunology of mucosal barriers in catfish (Ictalurus spp.)

    PubMed Central

    Peatman, Eric; Lange, Miles; Zhao, Honggang; Beck, Benjamin H

    2015-01-01

    The mucosal barriers of catfish (Ictalurus spp) constitute the first line of defense against pathogen invasion while simultaneously carrying out a diverse array of other critical physiological processes, including nutrient adsorption, osmoregulation, waste excretion, and environmental sensing. Catfish depend more heavily on mucosal barriers than their terrestrial counterparts as they are continuously interacting with the aquatic microbiota. Our understanding of these barriers, while growing, is still limited relative to that of mammalian model systems. Nevertheless, a combination of molecular and cellular studies in catfish over the last few decades, and particularly within the last few years, has helped to elucidate many of the primary actors and pathways critical to their mucosal health. Here we describe aspects of innate and adaptive immune responses in the primary mucosal tissues (skin, gill, and intestine) of catfish, focusing on mucus-driven responses, pathogen recognition, soluble mediators, and immunoglobulin and T-cell derived immunity. Modulation of mucosal barriers will be critical moving forward for crafting better diets, improving vaccine delivery, enhancing water quality, and ensuring sustainable production practices in catfish. PMID:26716071

  18. Iron medication-induced gastric mucosal injury.

    PubMed

    Zhang, Xuchen; Ouyang, Jie; Wieczorek, Rosemary; DeSoto, Fidelina

    2009-01-01

    Severe gastrointestinal erosion, ulcer, necrosis and strictures after an acute iron overdose are well described. However, gastric mucosal injury in patients receiving therapeutic iron has received only scant recognition despite its wide use. We report a case of iron medication-induced gastric mucosal injury in a 76-year-old male who presented with iron deficiency anemia and had been taking ferrous sulfate tablet for 4 years. Esophagogastroduodenoscopy (EGD) revealed a pale, villous appearing flat lesion along the lesser curvature of gastric body. Histopathologic examination of EGD biopsies of the flat lesion showed brown crystalline materials deposited in the lamina propria of gastric mucosa, which was accompanied with fibrosis, chronic inflammation, and foreign body reaction. The crystalline materials were covered and admixed with gastric epithelium. Prussian blue iron stain confirmed that the brown crystalline materials were iron. The iron and hemosiderin accumulation was also seen in cytoplasm of epithelial cells and lumen of fundic gastric glands. The recognition and reporting by pathologists of iron-induced changes in EGD biopsies will alert clinicians to this underrecognized but easily correctable complication by alternative forms of iron therapy, such as liquid preparation.

  19. Immunoglobulin Responses at the Mucosal Interface

    PubMed Central

    Chen, Kang; Chorny, Alejo

    2011-01-01

    Mucosal surfaces are colonized by large communities of commensal bacteria and represent the primary site of entry for pathogenic agents. To prevent microbial intrusion, mucosal B cells release large amounts of immunoglobulin (Ig) molecules through multiple follicular and extrafollicular pathways. IgA is the most abundant antibody isotype in mucosal secretions and owes its success in frontline immunity to its ability to undergo transcytosis across epithelial cells. In addition to translocating IgA onto the mucosal surface, epithelial cells educate the mucosal immune system as to the composition of the local microbiota and instruct B cells to initiate IgA responses that generate immune protection while preserving immune homeostasis. Here we review recent advances in our understanding of the cellular interactions and signaling pathways governing IgA production at mucosal surfaces and discuss new findings on the regulation and function of mucosal IgD, the most enigmatic isotype of our mucosal antibody repertoire. PMID:21219173

  20. Spectacular Rate Enhancement of the Diels-Alder Reaction at the Ionic Liquid/n-Hexane Interface.

    PubMed

    Beniwal, Vijay; Manna, Arpan; Kumar, Anil

    2016-07-04

    The use of the ionic liquid/n-hexane interface as a new class of reaction medium for the Diels-Alder reaction gives large rate enhancements of the order of 10(6) to 10(8) times and high stereoselectivity, as compared to homogeneous media. The rate enhancement is attributed to the H-bonding abilities and polarities of the ionic liquids, whereas the hydrophobicity of ionic liquids was considered to be the factor in controlling stereoselectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields

    SciTech Connect

    Miknis, F.P.

    1992-07-01

    The overall objectives of this work are to conduct research that will provide the basis for an improved liquefaction process, and to facilitate our understanding of those processes that occur when coals are initially dissolved. Changes in coal structure that occur during coal drying and steam pretreatments will be measured in order to determine what effect water has on retrograde/condensation reactions, and to determine the mechanism by which water enhances coal reactivity toward liquefaction. Different methods for coal drying will be investigated to determine if drying can be accomplished without destroying coal reactivity toward liquefaction, thereby making coal drying a relatively economical and efficient method for coal pretreatment. Coal drying methods will include conventional thermal drying, microwave drying, and chemical drying at low temperature. State-of-the-art solid-state nuclear magnetic resonance (NMR) techniques using combined rotation and multiple pulse spectroscopy (CRAMPS) and cross polarization with magic-angle spinning (CP/MAS) will be employed: (1) to measures changes in coal structure brought about by the different methods of drying and by low temperature oxidation, and (2) to obtain direct measurements of changes in the aromatic hydrogen-to-carbon ratio of the solid/semi-solid material formed or remaining during pretreatment and the initial stages of liquefaction. The aromatic hydrogen-to-carbon ratios are difficult, if not impossible, to measure without the use of solid-state NMR, and as a result this ratio will be used to monitor the retrograde/condensation reactions that take place during coal liquefaction in the presence and absence of steam and various inert gases.

  2. Immunology of Gut Mucosal Vaccines

    PubMed Central

    Pasetti, Marcela F.; Simon, Jakub K.; Sztein, Marcelo B.; Levine, Myron M.

    2011-01-01

    Summary Understanding the mechanisms underlying the induction of immunity in the gastrointestinal mucosa following oral immunization and the cross-talk between mucosal and systemic immunity should expedite the development of vaccines to diminish the global burden caused by enteric pathogens. Identifying an immunological correlate of protection in the course of field trials of efficacy, animal models (when available), or human challenge studies is also invaluable. In industrialized country populations, live attenuated vaccines (e.g. polio, typhoid, and rotavirus) mimic natural infection and generate robust protective immune responses. In contrast, a major challenge is to understand and overcome the barriers responsible for the diminished immunogenicity and efficacy of the same enteric vaccines in underprivileged populations in developing countries. Success in developing vaccines against some enteric pathogens has heretofore been elusive (e.g. Shigella). Different types of oral vaccines can selectively or inclusively elicit mucosal secretory immunoglobulin A and serum immunoglobulin G antibodies and a variety of cell-mediated immune responses. Areas of research that require acceleration include interaction between the gut innate immune system and the stimulation of adaptive immunity, development of safe yet effective mucosal adjuvants, better understanding of homing to the mucosa of immunologically relevant cells, and elicitation of mucosal immunologic memory. This review dissects the immune responses elicited in humans by enteric vaccines. PMID:21198669

  3. Differential Apoptosis in Mucosal and Dermal Wound Healing

    PubMed Central

    Johnson, Ariel; Francis, Marybeth; DiPietro, Luisa Ann

    2014-01-01

    Objectives: Dermal and mucosal healing are mechanistically similar. However, scarring and closure rates are dramatically improved in mucosal healing, possibly due to differences in apoptosis. Apoptosis, nature's preprogrammed form of cell death, occurs via two major pathways, extrinsic and intrinsic, which intersect at caspase3 (Casp3) cleavage and activation. The purpose of this experiment was to identify the predominant pathways of apoptosis in mucosal and dermal wound healing. Approach: Wounds (1 mm biopsy punch) were made in the dorsal skin (n=3) or tongue (n=3) of female Balb/C mice aged 6 weeks. Wounds were harvested at 6 h, 24 h, day 3 (D3), D5, D7, and D10. RNA was isolated and analyzed using real time reverse transcriptase–polymerase chain reaction. Expression levels for genes in the intrinsic and extrinsic apoptotic pathways were compared in dermal and mucosal wounds. Results: Compared to mucosal healing, dermal wounds exhibited significantly higher expression of Casp3 (at D5; p<0.05), Casp7 (at D5; p<0.05), Trp53 (at 24 h and D5; p<0.05), Tnfrsf1b (at 24 h; p<0.05), FasR (at 24 h, D5, and D7; p<0.05), and Casp8 (at 24 h; p<0.05) and significantly lower gene expression of Tradd (at 24 h; p<0.05). Innovation: Our observations indicate differential execution of apoptosis in oral wound healing compared to skin. Conclusion: Expression patterns of key regulators of apoptosis in wound healing indicate that apoptosis occurs predominantly through the intrinsic pathway in the healing mucosa, but predominantly through the extrinsic pathway in the healing skin. The identification of differences in the apoptotic pathways in skin and mucosal wounds may allow the development of therapeutics to improve skin healing. PMID:25493209

  4. Enhancing pyridinic nitrogen level in graphene to promote electrocatalytic activity for oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Sun, Jiaguang; Wang, Lan; Song, Ranran; Yanga, Shubin

    2016-02-01

    We develop an efficient approach to fabricate nitrogen-doped graphene with tunable pyridinic nitrogen levels (from 1.1 to 1.8 at.%), abundant in-plane holes and high surface areas (623 m2 g-1) via a hydrothermal treatment of graphene oxide with hydrogen peroxide and subsequent annealing under ammonia gas. It is found that the chemical etching is beneficial to the formation of pyridinic nitrogen in graphene during the nitrogen-doping process, which is crucial to enhancing the electrocatalytic properties of graphene for oxygen reduction reaction (ORR). Hence, the optimized NG exhibits good electrocatalytic activity, more positive onset potential than Pt-C (-0.08 V versus -0.09 V), good durability, and high selectivity when it is employed as a metal-free catalyst for ORR. This approach may uncover a mechanism in escalation of pyridinic N atoms doped on the graphene basal edge and provide an efficient platform for the synthesis of a series of heteroatom-doped graphene with tunable heteroatom content for broad applications.

  5. Sintering Behavior of Metal Powders Involving Microwave-Enhanced Chemical Reaction

    NASA Astrophysics Data System (ADS)

    Takayama, Sadatsugu; Saito, Yasushi; Sato, Motoyasu; Nagasaka, Takuya; Muroga, Takeo; Ninomiya, Yoshihiko

    2006-03-01

    Copper powder compacts were sintered by microwave radiation in air. In this procedure, the samples were sintered by microwave in air without using any special atmosphere, only by protecting them in a container filled with ceramic powder. The enhancement of the deoxidation reaction by the microwave was observed. The samples were analyzed by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis. The samples were deoxidized on the surface and were well sintered to the edge from the inside throughout the entire cross section. The tensile strength of the copper samples sintered by the microwave in air was higher than that found in conventional sintering in N2 gas. No other differences were noticed between the samples sintered by the microwave under the air-rich conditions and in the conventional furnace in H2+N2 gas. The microwave-sintered copper samples were of good quality; for example, the tensile strength measured throughout the cross section was the same as that for the samples sintered in H2+N2 gas by the conventional method.

  6. Comprehensive evaluation of molecular enhancers of the isothermal exponential amplification reaction

    PubMed Central

    Mok, Ellie; Wee, Eugene; Wang, Yuling; Trau, Matt

    2016-01-01

    The exponential amplification reaction (EXPAR) is an emerging isothermal nucleic acid amplification method with high potential for molecular diagnostics due to its isothermal nature and high amplification efficiency. However, the use of EXPAR is limited by the high levels of non-specific amplification. Hence, methods that can improve the specificity of EXPAR are desired to facilitate its widespread adoption in practice. Herein, we proposed a strategy to improve EXPAR performance by using molecular enhancers. Eight small molecules were investigated, including ethylene glycol, propylene glycol, betaine, dimethyl sulfoxide (DMSO), trehalose, tetramethylammonium chloride (TMAC), bovine serum albumin (BSA) and single-stranded binding (SSB) proteins. A combination of kinetic and end-point analysis was adopted to investigate how these molecules affected EXPAR performance. Trehalose, TMAC, BSA and SSB proteins were found to have positive effects on EXPAR with trehalose being able to increase the efficiency of EXPAR. In contrast, TMAC, BSA and SSB proteins were shown to increase the specificity of EXPAR. We applied our findings to demonstrate the combination of trehalose and TMAC could simultaneously improve both the efficiency and specificity of an EXPAR-based miRNA detection method. The information provided in this study may serve as a reference to benefit the wider isothermal amplification community. PMID:27910874

  7. Uniquely confining Cu2S nanoparticles in graphitized carbon fibers for enhanced oxygen evolution reaction.

    PubMed

    Zhao, Xiaoqian; Liu, Li; Zhang, Yan; Zhang, Huijuan; Wang, Yu

    2017-08-25

    Up to now, the literature on Cu2S with specific morphology applied to oxygen evolution reaction (OER) in the electrocatalytic field has been limited. In this work, unique peapod-like Cu2S/C exhibiting superb electrocatalytic performance toward OER is successfully synthesized, by employing Cu(OH)2 nanorods as the template and nontoxic glucose as the carbon source and then annealing with sublimed sulfur. It can be seen that this work explores a new application area for Cu2S. More precisely, the novel morphology contributes to increasing the electrochemical active surface area effectively and promoting contact between the Cu2S nanoparticles and the electrolyte. During electrochemical measurements, the peapod-like Cu2S/C shows enhanced electrocatalytic activity with a low overpotential of 401 mV at the current density of 10 mA cm(-2) and a Tafel slope of 52 mV dec(-1). More importantly, our material is able to maintain stability for at least 8 h at constant potential and the current loss is negligible after 2000 cycles. Obviously, these striking properties fully demonstrate that the peapod-like Cu2S/C as an efficient catalyst shows great promise for OER.

  8. Uniquely confining Cu2S nanoparticles in graphitized carbon fibers for enhanced oxygen evolution reaction

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoqian; Liu, Li; Zhang, Yan; Zhang, Huijuan; Wang, Yu

    2017-08-01

    Up to now, the literature on Cu2S with specific morphology applied to oxygen evolution reaction (OER) in the electrocatalytic field has been limited. In this work, unique peapod-like Cu2S/C exhibiting superb electrocatalytic performance toward OER is successfully synthesized, by employing Cu(OH)2 nanorods as the template and nontoxic glucose as the carbon source and then annealing with sublimed sulfur. It can be seen that this work explores a new application area for Cu2S. More precisely, the novel morphology contributes to increasing the electrochemical active surface area effectively and promoting contact between the Cu2S nanoparticles and the electrolyte. During electrochemical measurements, the peapod-like Cu2S/C shows enhanced electrocatalytic activity with a low overpotential of 401 mV at the current density of 10 mA cm-2 and a Tafel slope of 52 mV dec-1. More importantly, our material is able to maintain stability for at least 8 h at constant potential and the current loss is negligible after 2000 cycles. Obviously, these striking properties fully demonstrate that the peapod-like Cu2S/C as an efficient catalyst shows great promise for OER.

  9. Synthetic polyacrylate polymers as particulate intranasal vaccine delivery systems for the induction of mucosal immune response.

    PubMed

    Zaman, Mehfuz; Simerska, Pavla; Toth, Istvan

    2010-04-01

    The nasal route as a site of vaccine delivery for both local and systemic effect is currently of considerable interest. The administration of vaccines to mucosal surfaces such as the nasopharynx associated lymphoid tissues confers many advantages since the nasal mucosa is a primary site through which most inhaled antigens are encountered. However, the success of intranasally delivered mucosal vaccines is limited by lack of effective vaccine formulations or delivery systems suitable for use in humans. This review provides a brief overview of the mucosal immune system at the nasal surface, enhancement techniques for induction of mucosal immune response after intranasal administration of particulate systems and an explanation of the inherent properties of polyacrylate polymer-based particulate systems that may facilitate mucosal immune responses.

  10. PPS nanoparticles as versatile delivery system to induce systemic and broad mucosal immunity after intranasal administration.

    PubMed

    Stano, Armando; van der Vlies, André J; Martino, Mikael M; Swartz, Melody A; Hubbell, Jeffrey A; Simeoni, Eleonora

    2011-01-17

    Degradable polymer nanoparticles (NPs, 50 nm) based on polypropylene sulfide (PPS) were conjugated to thiolated antigen and adjuvant proteins by reversible disulfide bonds and evaluated in mucosal vaccination. Ovalbumin was used as a model antigen, and antigen-conjugated NPs were administered intranasally in the mouse. We show penetration of nasal mucosae, transit via M cells, and uptake by antigen-presenting cells in the nasal-associated lymphoid tissue. Ovalbumin-conjugated NPs induced cytotoxic T lymphocytic responses in lung and spleen tissues, as well as humoral response in mucosal airways. Co-conjugation of the TLR5 ligand flagellin further enhanced humoral responses in the airways as well as in the distant vaginal and rectal mucosal compartments and induced cellular immune responses with a Th1 bias, in contrast with free flagellin. The PPS NP platform thus appears interesting as a platform for intranasally-administered mucosal vaccination for inducing broad mucosal immunity.

  11. Observing Metal-Catalyzed Chemical Reactions in Situ Using Surface-Enhanced Raman Spectroscopy on Pd–Au Nanoshells

    PubMed Central

    Heck, Kimberly N.; Janesko, Benjamin G.; Scuseria, Gustavo E.

    2016-01-01

    Insight into the nature of transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions is obtainable from a number of surface spectroscopic techniques. Carrying out these investigations under actual reaction conditions is preferred but remains challenging, especially for catalytic reactions that occur in water. Here, we report the direct spectroscopic study of the catalytic hydrodechlorination of 1,1-dichloroethene in H2O using surface-enhanced Raman spectroscopy (SERS). With Pd islands grown on Au nanoshell films, this reaction can be followed in situ using SERS, exploiting the high enhancements and large active area of Au nanoshell SERS substrates, the transparency of Raman spectroscopy to aqueous solvents, and the catalytic activity enhancement of Pd by the underlying Au metal. The formation and subsequent transformation of several adsorbate species was observed. These results provide the first direct evidence of the room-temperature catalytic hydrodechlorination of a chlorinated solvent, a potentially important pathway for groundwater cleanup, as a sequence of dechlorination and hydrogenation steps. More broadly, the results highlight the exciting prospects of studying catalytic processes in water in situ, like those involved in biomass conversion and proton-exchange membrane fuel cells. PMID:19554693

  12. Experimental Study on Impact-Induced Reaction Characteristics of PTFE/Ti Composites Enhanced by W Particles

    PubMed Central

    Li, Yan; Wang, Zaicheng; Jiang, Chunlan; Niu, Haohao

    2017-01-01

    Metal/fluoropolymer composites are a category of energetic structural materials that release energy through exothermic chemical reactions initiated under highly dynamic loadings. In this paper, the chemical reaction mechanism of PTFE (polytetrafluoroethylene)/Ti/W composites is investigated through thermal analysis and composition analysis. These composites undergo exothermic reactions at 510 °C to 600 °C, mainly producing TiFx. The tungsten significantly reduces the reaction heat due to its inertness. In addition, the dynamic compression properties and impact-induced reaction behaviors of PTFE/Ti/W composites with different W content prepared by pressing and sintering are studied using Split Hopkinson Pressure Bar and high speed photography. The results show that both the mechanical strength and the reaction degree are significantly improved with the increasing strain rate. Moreover, as W content increases, the mechanical strength is enhanced, but the elasticity/plasticity is decreased. The PTFE/Ti/W composites tend to become more inert with the increasing W content, which is reflected by the reduced reaction degree and the increased reaction threshold for the impact ignition. PMID:28772534

  13. Experimental Study on Impact-Induced Reaction Characteristics of PTFE/Ti Composites Enhanced by W Particles.

    PubMed

    Li, Yan; Wang, Zaicheng; Jiang, Chunlan; Niu, Haohao

    2017-02-13

    Metal/fluoropolymer composites are a category of energetic structural materials that release energy through exothermic chemical reactions initiated under highly dynamic loadings. In this paper, the chemical reaction mechanism of PTFE (polytetrafluoroethylene)/Ti/W composites is investigated through thermal analysis and composition analysis. These composites undergo exothermic reactions at 510 °C to 600 °C, mainly producing TiFx. The tungsten significantly reduces the reaction heat due to its inertness. In addition, the dynamic compression properties and impact-induced reaction behaviors of PTFE/Ti/W composites with different W content prepared by pressing and sintering are studied using Split Hopkinson Pressure Bar and high speed photography. The results show that both the mechanical strength and the reaction degree are significantly improved with the increasing strain rate. Moreover, as W content increases, the mechanical strength is enhanced, but the elasticity/plasticity is decreased. The PTFE/Ti/W composites tend to become more inert with the increasing W content, which is reflected by the reduced reaction degree and the increased reaction threshold for the impact ignition.

  14. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    ERIC Educational Resources Information Center

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  15. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    ERIC Educational Resources Information Center

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  16. Why Chitosan? From properties to perspective of mucosal drug delivery.

    PubMed

    Kumar, Ashwini; Vimal, Archana; Kumar, Awanish

    2016-10-01

    Non-parenteral drug delivery routes primarily remove the local pain at the injection site. The drugs administered through the oral route encounter the process of hepatic first pass metabolism. Among the alternative delivery routes, mucosal route is being investigated as the most preferred route. Different mucosal routes include the gastrointestinal tract (oral), vagina, buccal cavity and nasal cavity. Novel formulations are being developed using natural and synthetic polymers that could increase the residence time of the drug at mucosal surface in order to facilitate permeation and reduce (or bypass) the first pass metabolism. For recombinant drugs, the formulations are accompanied by enzyme inhibitors and penetration enhancers. Buccal cavity (buccal and sublingual mucosa) has smaller surface area than the gastrointestinal tract but the drugs can easily escape the first pass metabolism. Chitosan is the most applied natural polymer while synthetic polymers include Carbopol and Eudragit. Chitosan has inherent properties of mucoadhesion and penetration enhancement apart from biodegradability and efflux pump inhibition. This review hoards the important research purview of chitosan as a compatible drug carrier macromolecule for mucosal delivery on single platform.

  17. Primary mucosal melanomas: a comprehensive review

    PubMed Central

    Mihajlovic, Marija; Vlajkovic, Slobodan; Jovanovic, Predrag; Stefanovic, Vladisav

    2012-01-01

    Primary mucosal melanomas arise from melanocytes located in mucosal membranes lining respiratory, gastrointestinal and urogenital tract. Although a majority of mucosal melanomas originate from the mucosa of the nasal cavity and accessory sinuses, oral cavity, anorectum, vulva and vagina, they can arise in almost any part of mucosal membranes. Most of mucosal melanomas occur in occult sites, which together with the lack of early and specific signs contribute to late diagnosis, and poor prognosis. Because of their rareness the knowledge about their pathogenesis and risk factors is insufficient, and also there are not well established protocols for staging and treatment of mucosal melanomas. Surgery is the mainstay of treatment, with trends toward more conservative treatment since radical surgery did not show an advantage for survival. Radiotherapy can provide better local control in some locations, but did not show improvement in survival. There is no effective systemic therapy for these aggressive tumors. Compared with cutaneous and ocular melanoma, mucosal melanomas have lowest percent of five-year survival. Recently revealed molecular changes underlying mucosal melanomas offer new hope for development of more effective systemic therapy for mucosal melanomas. Herein we presented a comprehensive review of various locations of primary melanoma along mucosal membranes, their epidemiological and clinical features, and treatment options. We also gave a short comparison of some characteristics of cutaneous and mucosal melanomas. PMID:23071856

  18. The Mucosal Immune System of Teleost Fish

    PubMed Central

    Salinas, Irene

    2015-01-01

    Teleost fish possess an adaptive immune system associated with each of their mucosal body surfaces. Evidence obtained from mucosal vaccination and mucosal infection studies reveal that adaptive immune responses take place at the different mucosal surfaces of teleost. The main mucosa-associated lymphoid tissues (MALT) of teleosts are the gut-associated lymphoid tissue (GALT), skin-associated lymphoid tissue (SALT), the gill-associated lymphoid tissue (GIALT) and the recently discovered nasopharynx-associated lymphoid tissue (NALT). Teleost MALT includes diffuse B cells and T cells with specific phenotypes different from their systemic counterparts that have co-evolved to defend the microbe-rich mucosal environment. Both B and T cells respond to mucosal infection or vaccination. Specific antibody responses can be measured in the gills, gut and skin mucosal secretions of teleost fish following mucosal infection or vaccination. Rainbow trout studies have shown that IgT antibodies and IgT+ B cells are the predominant B cell subset in all MALT and respond in a compartmentalized manner to mucosal infection. Our current knowledge on adaptive immunity in teleosts is limited compared to the mammalian literature. New research tools and in vivo models are currently being developed in order to help reveal the great intricacy of teleost mucosal adaptive immunity and help improve mucosal vaccination protocols for use in aquaculture. PMID:26274978

  19. Atmospheric CO2 uptake throughout bio-enhanced brucite-water reaction at Montecastelli serpentinites (Italy)

    NASA Astrophysics Data System (ADS)

    Bedini, Federica; Boschi, Chiara; Ménez, Benedicte; Perchiazzi, Natale; Zanchetta, Giovanni

    2014-05-01

    active microbial communities in or at the serpentinites surface could promote and/or enhance the key reaction through which serpentine, reacting with the carbon dioxide, becomes hydrated Mg-carbonates. This novel study aims to provide a contribution to the identification of the biominerals that could be a valid proof between CO2-mineral sequestration and microbial activity interactions. This innovative research is designed to provide a plan in future at industrial scale to reduce and capture the greenhouse gas content by Earth's atmosphere, thanks to the precipitation of carbonate biominerals. Keywords: serpentinite, carbonation, biominerals. Bedini F., Boschi C., Ménez B., Perchiazzi N., Natali C., Zanchetta G. (2013) Interaction between Geosphere and Biosphere in CO2-mineral sequestration environment. FIST GEOITALIA 2013- XI Forum di Scienze della Terra (Pisa, Italy).

  20. Nystatin and lidocaine pastilles for the local treatment of oral mucositis.

    PubMed

    Silva, Filipa Cosme; Marto, Joana M; Salgado, Ana; Machado, Paula; Silva, Alexandra N; Almeida, António J

    2017-03-01

    Oral mucositis (OM) is a common adverse reaction to radiotherapy and chemotherapy in oncology. Its treatment requires oral formulations that enhance therapy compliance, improve administration and ensure drug effectiveness. Solid dosage forms that act by slow dissolution, such as pastilles, are an effective alternative to mouthwashes, for their versatility, ease of administration and extended residence time in the oral cavity. The present work describes the development and stability studies of an innovative formulation of nystatin and lidocaine pastilles for the treatment of oral mucositis. Full pharmaceutical quality testing was carried out, including disintegration and dissolution testing, texture profile analysis, grittiness and an antifungal activity testing. A soft pastille formulation containing 0.25% lidocaine and 78,000 IU nystatin was obtained, presenting suitable pharmaceutical characteristics, as a disintegration time of 17 ± 2 min, dissolution rate and microbiological and physicochemical for 30 days when stored at 2-8 °C under light protection. Palatability was also evaluated, being well accepted by a panel of 38 healthy volunteers. This formulation allows an accurate drug dosing by the prescriber, while enabling the patients to control the retention time of the drugs in the oral cavity and consequently manage their pain treatment.

  1. Diet-Induced Obesity Enhances TRPV1-Mediated Neurovascular Reactions in the Dura Mater.

    PubMed

    Marics, Balázs; Peitl, Barna; Pázmándi, Kitti; Bácsi, Attila; Németh, József; Oszlács, Orsolya; Jancsó, Gábor; Dux, Mária

    2017-03-01

    -induced CGRP release from meningeal afferents ex vivo. Except for minor morphological changes, the distribution of dural TRPV1- and CGRP-immunoreactive afferents was similar in control and obese animals. Our results suggest that obesity induced by long-term HFHS diet results in sensitization of the trigeminovascular system. Changes in TRPV1-mediated vascular reactions and CGRP release are pathophysiological alterations that may be of relevance to the enhanced headache susceptibility of obese individuals. © 2017 American Headache Society.

  2. Mucosal drug delivery: membranes, methodologies, and applications.

    PubMed

    Song, Yifan; Wang, Yiping; Thakur, Rashmi; Meidan, Victor M; Michniak, Bozena

    2004-01-01

    In recent years, extensive research into novel forms of drug delivery has suggested that mucosal approaches offer a promising therapeutic alternative, especially for systemically acting drugs. Transmucosal drug delivery offers many benefits, including noninvasive administration, convenience, rapid onset, as well as elimination of hepatic first-pass metabolism. The investigated absorptive surfaces consist of the nasal, buccal, ocular, vaginal, and rectal mucosae. Among these, the nasal and buccal routes have proved the most promising to date. The bioavailability achieved mainly depends upon the pathophysiological state of the mucosa and the properties of both the drug and delivery systems. Various agents can increase the efficacy of transmucosal drug delivery. These include cyclodextrins, bile salts, surfactants, fusidic acid derivatives, microspheres, liposomes, and bioadhesive agents. The mechanisms of action, effectiveness, and toxicity profiles of these enhancers have been investigated extensively in both animal and human models.

  3. Cryopreservation of Human Mucosal Leukocytes

    PubMed Central

    Shu, Zhiquan; Levy, Claire N.; Ferre, April L.; Hartig, Heather; Fang, Cifeng; Lentz, Gretchen; Fialkow, Michael; Kirby, Anna C.; Adams Waldorf, Kristina M.; Veazey, Ronald S.; Germann, Anja; von Briesen, Hagen; McElrath, M. Juliana; Dezzutti, Charlene S.; Sinclair, Elizabeth; Baker, Chris A. R.; Shacklett, Barbara L.; Gao, Dayong; Hladik, Florian

    2016-01-01

    Background Understanding how leukocytes in the cervicovaginal and colorectal mucosae respond to pathogens, and how medical interventions affect these responses, is important for developing better tools to prevent HIV and other sexually transmitted infections. An effective cryopreservation protocol for these cells following their isolation will make studying them more feasible. Methods and Findings To find an optimal cryopreservation protocol for mucosal mononuclear leukocytes, we compared cryopreservation media and procedures using human vaginal leukocytes and confirmed our results with endocervical and colorectal leukocytes. Specifically, we measured the recovery of viable vaginal T cells and macrophages after cryopreservation with different cryopreservation media and handling procedures. We found several cryopreservation media that led to recoveries above 75%. Limiting the number and volume of washes increased the fraction of cells recovered by 10–15%, possibly due to the small cell numbers in mucosal samples. We confirmed that our cryopreservation protocol also works well for both endocervical and colorectal leukocytes. Cryopreserved leukocytes had slightly increased cytokine responses to antigenic stimulation relative to the same cells tested fresh. Additionally, we tested whether it is better to cryopreserve endocervical cells on the cytobrush or in suspension. Conclusions Leukocytes from cervicovaginal and colorectal tissues can be cryopreserved with good recovery of functional, viable cells using several different cryopreservation media. The number and volume of washes has an experimentally meaningful effect on the percentage of cells recovered. We provide a detailed, step-by-step protocol with best practices for cryopreservation of mucosal leukocytes. PMID:27232996

  4. Mucosal immunology of food allergy.

    PubMed

    Berin, M Cecilia; Sampson, Hugh A

    2013-05-06

    Food allergies are increasing in prevalence at a higher rate than can be explained by genetic factors, suggesting a role for as yet unidentified environmental factors. In this review, we summarize the state of knowledge about the healthy immune response to antigens in the diet and the basis of immune deviation that results in immunoglobulin E (IgE) sensitization and allergic reactivity to foods. The intestinal epithelium forms the interface between the external environment and the mucosal immune system, and emerging data suggest that the interaction between intestinal epithelial cells and mucosal dendritic cells is of particular importance in determining the outcome of immune responses to dietary antigens. Exposure to food allergens through non-oral routes, in particular through the skin, is increasingly recognized as a potentially important factor in the increasing rate of food allergy. There are many open questions on the role of environmental factors, such as dietary factors and microbiota, in the development of food allergy, but data suggest that both have an important modulatory effect on the mucosal immune system. Finally, we discuss recent developments in our understanding of immune mechanisms of clinical manifestations of food allergy. New experimental tools, particularly in the field of genomics and the microbiome, are likely to shed light on factors responsible for the growing clinical problem of food allergy.

  5. Mucosal vaccination: lung versus nose.

    PubMed

    Vujanic, Ana; Sutton, Philip; Snibson, Kenneth J; Yen, Hung-Hsun; Scheerlinck, Jean-Pierre Y

    2012-07-15

    The induction of potent mucosal immune responses able to prevent the establishment of infection at the onset of mucosal pathogen colonisation represents a desirable but challenging goal for vaccine development. Here we compare nasal vaccine delivery with intra-pulmonary vaccination using a sheep lymphatic cannulation model. Our results demonstrate that nasal delivery of a non-infective ISCOMATRIX(®) influenza vaccine does not induce primary immune responses in the lymph draining the nasal lymph nodes, suggesting that local immune responses in the lymph nodes draining the nasal cavity are relatively weak. However, this mode of delivery can boost existing immunity in the nasal lymph. Using the same adjuvant we were able to induce very potent immune responses in both blood and bronchoalveolar lavage (BAL), following intra-pulmonary delivery of ISCOMATRIX(®) influenza vaccine, even when very small doses of antigen were employed. Lung delivery could also induce comparable immune responses against other recombinant antigens mixed with ISCOMATRIX(®) adjuvant and could therefore become a method of choice for the induction of immunity to mucosal pathogens infecting the lower respiratory tract. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Cryopreservation of Human Mucosal Leukocytes.

    PubMed

    Hughes, Sean M; Shu, Zhiquan; Levy, Claire N; Ferre, April L; Hartig, Heather; Fang, Cifeng; Lentz, Gretchen; Fialkow, Michael; Kirby, Anna C; Adams Waldorf, Kristina M; Veazey, Ronald S; Germann, Anja; von Briesen, Hagen; McElrath, M Juliana; Dezzutti, Charlene S; Sinclair, Elizabeth; Baker, Chris A R; Shacklett, Barbara L; Gao, Dayong; Hladik, Florian

    2016-01-01

    Understanding how leukocytes in the cervicovaginal and colorectal mucosae respond to pathogens, and how medical interventions affect these responses, is important for developing better tools to prevent HIV and other sexually transmitted infections. An effective cryopreservation protocol for these cells following their isolation will make studying them more feasible. To find an optimal cryopreservation protocol for mucosal mononuclear leukocytes, we compared cryopreservation media and procedures using human vaginal leukocytes and confirmed our results with endocervical and colorectal leukocytes. Specifically, we measured the recovery of viable vaginal T cells and macrophages after cryopreservation with different cryopreservation media and handling procedures. We found several cryopreservation media that led to recoveries above 75%. Limiting the number and volume of washes increased the fraction of cells recovered by 10-15%, possibly due to the small cell numbers in mucosal samples. We confirmed that our cryopreservation protocol also works well for both endocervical and colorectal leukocytes. Cryopreserved leukocytes had slightly increased cytokine responses to antigenic stimulation relative to the same cells tested fresh. Additionally, we tested whether it is better to cryopreserve endocervical cells on the cytobrush or in suspension. Leukocytes from cervicovaginal and colorectal tissues can be cryopreserved with good recovery of functional, viable cells using several different cryopreservation media. The number and volume of washes has an experimentally meaningful effect on the percentage of cells recovered. We provide a detailed, step-by-step protocol with best practices for cryopreservation of mucosal leukocytes.

  7. Mucosal Immunology of Food Allergy

    PubMed Central

    Berin, M. Cecilia; Sampson, Hugh A.

    2013-01-01

    Food allergies are increasing in prevalence at a higher rate than can be explained by genetic factors, suggesting a role for as yet unidentified environmental factors. In this review, we summarize the state of knowledge about the healthy immune response to antigens in the diet and the basis of immune deviation that results in IgE sensitization and allergic reactivity to foods. The intestinal epithelium forms the interface between the external environment and the mucosal immune system, and emerging data suggest that the interaction between intestinal epithelial cells and mucosal dendritic cells is of particular importance in determining the outcome of immune responses to dietary antigens. Exposure to food allergens through non-oral routes, in particular through the skin, is increasingly recognized as a potentially important factor in the increasing rate of food allergy. There are many open questions on the role of environmental factors such as dietary factors and microbiota in the development of food allergy, but data suggest that both have an important modulatory effect on the mucosal immune system. Finally, we discuss recent developments in our understanding of immune mechanisms of clinical manifestations of food allergy. New experimental tools, particularly in the field of genomics and microbiome, are likely to shed light on factors responsible for the growing clinical problem of food allergy. PMID:23660362

  8. Vestibuloplasty: allograft versus mucosal graft.

    PubMed

    Hashemi, H M; Parhiz, A; Ghafari, S

    2012-04-01

    The aim of the present study was to compare the application of alloderm and mucosal graft for vestibuloplasty. This randomized controlled trial with split mouth design was carried out on 20 edentulous patients. Patients underwent vestibuloplasty surgery with the Clark technique. Half of the prepared bed in each patient was covered with alloderm and the other half with mucosal graft. Vestibule depth (width of fixed tissue) and relapse in the two sides immediately after surgery, and 1, 3 and 6 months after surgery were measured and compared. Statistical analysis was carried out using the Kolmogorov-Smirnov, Student's paired t and Friedman tests. The width of the fixed tissue in the alloderm graft at 1, 3 and 6 month intervals was significantly lower than that in the autograft (P<0.05). The difference in relapse between the two grafts was not statistically significant at any time. The results of the study suggest that alloderm is as effective as mucosal grafts in vestibuloplasty. Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. All rights reserved.

  9. Enhancement of water-gas shift reaction efficiency: catalysts and the catalyst bed arrangement

    NASA Astrophysics Data System (ADS)

    Baronskaya, Natal'ya A.; Minyukova, Tat'yana P.; Khassin, Aleksandr A.; Yurieva, Tamara M.; Parmon, Valentin N.

    2010-12-01

    The results of studies devoted to the search for catalysts of water-gas shift (WGS) reaction that are highly active in a wide temperature interval are generalized. New compositions based on traditional and alternative, as regards the chemical composition, catalysts of high- and low-temperature WGS reaction are considered in detail. The single-stage arrangement of WGS reaction ensuring small temperature gradients in the radial direction of the catalyst bed are discussed.

  10. Quantitative rate determination by dynamic nuclear polarization enhanced NMR of a Diels-Alder reaction.

    PubMed

    Zeng, Haifeng; Lee, Youngbok; Hilty, Christian

    2010-11-01

    Emerging techniques for hyperpolarization of nuclear spins, foremost dynamic nuclear polarization (DNP), lend unprecedented sensitivity to nuclear magnetic resonance spectroscopy. Sufficient signal can be obtained from a single scan, and reactions even far from equilibrium can be studied in real-time. When following the progress of a reaction by nuclear magnetic resonance, however, spin relaxation occurs concomitantly with the reaction to alter resonance line intensities. Here, we present a model for accounting for spin-relaxation in such reactions studied by hyperpolarized NMR. The model takes into account auto- and cross-relaxation in dipole-dipole coupled spin systems and is therefore applicable to NMR of hyperpolarized protons, the most abundant NMR-active nuclei. Applied to the Diels-Alder reaction of 1,4-dipheneylbutadiene (DPBD) with 4-phenyl-1,2,4-triazole-3,5-dione (PTD), reaction rates could be obtained accurately and reproducibly. Additional parameters available from the same experiment include relaxation rates of the reaction product, which may yield further information about the molecular properties of the product. The method presented is also compatible with an experiment where a single spin in the reactant is labeled in its spin-state by a selective radio frequency pulse for subsequent tracking through the reaction, allowing the unambiguous identification of its position in the product molecule. In this case, the chemical shift specificity of high-resolution NMR can allow for the simultaneous determination of reaction rates and mechanistic information in one experiment.

  11. Elite Control, Gut CD4 T Cell Sparing, and Enhanced Mucosal T Cell Responses in Macaca nemestrina Infected by a Simian Immunodeficiency Virus Lacking a gp41 Trafficking Motif

    PubMed Central

    Breed, Matthew W.; Elser, Samra E.; Torben, Workineh; Jordan, Andrea P. O.; Aye, Pyone P.; Midkiff, Cecily; Schiro, Faith; Sugimoto, Chie; Alvarez-Hernandez, Xavier; Blair, Robert V.; Somasunderam, Anoma; Utay, Netanya S.; Kuroda, Marcelo J.; Pahar, Bapi; Wiseman, Roger W.; O'Connor, David H.; LaBranche, Celia C.; Montefiori, David C.; Marsh, Mark; Li, Yuan; Piatak, Michael; Lifson, Jeffrey D.; Keele, Brandon F.; Fultz, Patricia N.; Lackner, Andrew A.

    2015-01-01

    ABSTRACT Deletion of Gly-720 and Tyr-721 from a highly conserved GYxxØ trafficking signal in the SIVmac239 envelope glycoprotein cytoplasmic domain, producing a virus termed ΔGY, leads to a striking perturbation in pathogenesis in rhesus macaques (Macaca mulatta). Infected macaques develop immune activation and progress to AIDS, but with only limited and transient infection of intestinal CD4+ T cells and an absence of microbial translocation. Here we evaluated ΔGY in pig-tailed macaques (Macaca nemestrina), a species in which SIVmac239 infection typically leads to increased immune activation and more rapid progression to AIDS than in rhesus macaques. In pig-tailed macaques, ΔGY also replicated acutely to high peak plasma RNA levels identical to those for SIVmac239 and caused only transient infection of CD4+ T cells in the gut lamina propria and no microbial translocation. However, in marked contrast to rhesus macaques, 19 of 21 pig-tailed macaques controlled ΔGY replication with plasma viral loads of <15 to 50 RNA copies/ml. CD4+ T cells were preserved in blood and gut for up to 100 weeks with no immune activation or disease progression. Robust antiviral CD4+ T cell responses were seen, particularly in the gut. Anti-CD8 antibody depletion demonstrated CD8+ cellular control of viral replication. Two pig-tailed macaques progressed to disease with persisting viremia and possible compensatory mutations in the cytoplasmic tail. These studies demonstrate a marked perturbation in pathogenesis caused by ΔGY's ablation of the GYxxØ trafficking motif and reveal, paradoxically, that viral control is enhanced in a macaque species typically predisposed to more pathogenic manifestations of simian immunodeficiency virus (SIV) infection. IMPORTANCE The pathogenesis of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) reflects a balance between viral replication, host innate and adaptive antiviral immune responses, and sustained immune activation

  12. [Dental materials can cause oral allergic reactions].

    PubMed

    Røn Larsen, Kristine; Johansen, Jeanne Duus; Arenholt-Bindslev, Dorthe; Reibel, Jesper; Pedersen, Anne Marie Lynge

    2013-06-17

    A large number of materials used in the diagnosis, treatment and prevention of dental, periodontal and oral mucosal diseases may induce acute or chronic reactions in the oral cavity including allergic reactions. Clinically, it may be difficult to discriminate oral mucosal changes caused by dental materials from changes related to oral mucosal diseases. Diagnosis and management of allergic reactions in the oral mucosa may therefore be a major challenge. The purpose of this paper is to draw attention to commonly used dental materials, which can trigger typical, but also atypical, symptoms and clinical signs of an allergic reaction.

  13. Pharmacological Protection From Radiation {+-} Cisplatin-Induced Oral Mucositis

    SciTech Connect

    Cotrim, Ana P.; Yoshikawa, Masanobu; Sunshine, Abraham N.; Zheng Changyu; Sowers, Anastasia L.; Thetford, Angela D.; Cook, John A.; Mitchell, James B.; Baum, Bruce J.

    2012-07-15

    Purpose: To evaluate if two pharmacological agents, Tempol and D-methionine (D-met), are able to prevent oral mucositis in mice after exposure to ionizing radiation {+-} cisplatin. Methods and Materials: Female C3H mice, {approx}8 weeks old, were irradiated with five fractionated doses {+-} cisplatin to induce oral mucositis (lingual ulcers). Just before irradiation and chemotherapy, mice were treated, either alone or in combination, with different doses of Tempol (by intraperitoneal [ip] injection or topically, as an oral gel) and D-met (by gavage). Thereafter, mice were sacrificed and tongues were harvested and stained with a solution of Toluidine Blue. Ulcer size and tongue epithelial thickness were measured. Results: Significant lingual ulcers resulted from 5 Multiplication-Sign 8 Gy radiation fractions, which were enhanced with cisplatin treatment. D-met provided stereospecific partial protection from lingual ulceration after radiation. Tempol, via both routes of administration, provided nearly complete protection from lingual ulceration. D-met plus a suboptimal ip dose of Tempol also provided complete protection. Conclusions: Two fairly simple pharmacological treatments were able to markedly reduce chemoradiation-induced oral mucositis in mice. This proof of concept study suggests that Tempol, alone or in combination with D-met, may be a useful and convenient way to prevent the severe oral mucositis that results from head-and-neck cancer therapy.

  14. Pharmacological protection from radiation ± Cisplatin - induced oral mucositis

    PubMed Central

    Cotrim, Ana P.; Yoshikawa, Masanobu; Sunshine, Abraham N.; Zheng, Changyu; Sowers, Anastasia L.; Thetford, Angela D.; Cook, John A.; Mitchell, James B.; Baum, Bruce J.

    2011-01-01

    Purpose To evaluate if two pharmacological agents, Tempol and D-methionine (D-met), are able to prevent oral mucositis in mice following exposure to ionizing radiation ± Cisplatin. Methods and Materials Female C3H mice, ~8 weeks old, were irradiated with five fractionated doses ± Cisplatin to induce oral mucositis (lingual ulcers). Just prior to irradiation and chemotherapy, mice were treated, either alone or in combination, with different doses of Tempol (by intraperitoneal, ip, injection or topically, as an oral gel) and D-met (by gavage). Thereafter, mice were sacrificed, tongues harvested and stained with a solution of Toluidine Blue. Ulcer size and tongue epithelial thickness were measured. Results Significant lingual ulcers resulted from 5 × 8 Gy radiation fractions, which were enhanced with Cisplatin treatment. D-met provided stereospecific partial protection from lingual ulceration after radiation. Tempol, via both routes of administration, provided nearly complete protection from lingual ulceration. D-met plus a suboptimal ip dose of Tempol also provided complete protection. Conclusions Two fairly simple pharmacological treatments were able to markedly reduce chemoradiation-induced oral mucositis in mice. This proof of concept study suggests that Tempol, alone or in combination with D-met, may be a useful and convenient way to prevent the severe oral mucositis that results from head and neck cancer therapy. PMID:22197226

  15. Directed surfaces structures and interfaces for enhanced electrocatalyst activity, selectivity, and stability for energy conversion reactions

    SciTech Connect

    Jaramillo, Thomas F.

    2016-04-20

    In this project, we have employed a systematic approach to develop active, selective, and stable catalyst materials for important electrochemical reactions involving energy conversion. In particular, we have focused our attention on developing active catalyst materials for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). HER: We have synthesized and investigated several highly active and acid stable non-precious metal HER catalysts, including: [Mo3S13]2- nanoclusters (Nature Chemistry, 2014) and molybdenum phosphosulfide (MoP|S) (Angewandte Chemie, 2014). We have also aimed to engineer these catalyst formulations in a membrane electrode assembly (MEA) for fundamental studies of water electrolysis at high current densities, approximately 1 A/cm2 (ChemSusChem, 2015). We furthermore investigated transition metal phosphide (TMP) catalysts for HER by a combined experimental–theoretical approach (Energy & Environmental Science, 2015). By synthesizing different TMPs and comparing experimentally determined HER activities with the hydrogen adsorption free energies, ΔGH, calculated by density functional theory, we showed that the TMPs follow a volcano relationship for the HER. Using our combined experimental–theoretical model, we predicted that the mixed metal TMP, Fe0.5Co0.5P, should have a near-optimal ΔGH. We synthesized several mixtures of Co and Fe phosphides alloys and confirmed that Fe0.5Co0.5P exhibits the highest HER activity of the investigated TMPs (Energy & Environmental Science, 2015). The understanding gained as to how to improve catalytic activity for the HER, particularly for non-precious metal materials, is important to DOE targets for sustainable H2 production. OER: We have developed a SrIrO3/IrOx catalyst for acidic conditions (submitted, 2016). The Sr

  16. Rapid cortisol enhancement of psychomotor and startle reactions to side-congruent stimuli in a focused cross-modal choice reaction time paradigm.

    PubMed

    Schilling, Thomas M; Larra, Mauro F; Deuter, Christian E; Blumenthal, Terry D; Schächinger, Hartmut

    2014-11-01

    The stress hormone cortisol has been shown to affect hemodynamic activity of human brain structures, presumably via a nongenomic mechanism. However, behavioral implications of this finding remain unknown. In a placebo-controlled, blinded, cross-over design the rapid effects of IV hydrocortisone (5mg) on cross-modal integration of simultaneous, unilateral visual and acoustic signals in a challenging startle and reaction time (RT) paradigm were studied. On two separate days 1 week apart, 24 male volunteers responded by button push to either up- or down pointing triangles presented in random sequence in the periphery of one of the visual hemi-fields. Visual targets were accompanied by unilateral acoustic startle noise bursts, presented at the same or opposite side. Saccadic latency, manual RT, and startle eye blink responses were recorded. Faster manual reactions and increased startle eye blink responses were observed 11-20 min after hydrocortisone administration when visual targets and unilateral acoustic startle noises were presented in the same sensory hemi-field, but not when presented in opposite sensory hemi-fields. Our results suggest that a nongenomic, cortisol-sensitive mechanism enhances psychomotor and startle reactions when stimuli occur in the same sensory hemi-field. Such basic cognitive effects of cortisol may serve rapid adaptation and protection against danger stimuli in stressful contexts. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  17. The Therapeutic Effect of PLAG against Oral Mucositis in Hamster and Mouse Model

    PubMed Central

    Lee, Ha-Reum; Yoo, Nina; Kim, Joo Heon; Sohn, Ki-Young; Kim, Heung-Jae; Kim, Myung-Hwan; Han, Mi Young; Yoon, Sun Young; Kim, Jae Wha

    2016-01-01

    Chemotherapy-induced mucositis can limit the effectiveness of cancer therapy and increase the risk of infections. However, no specific therapy for protection against mucositis is currently available. In this study, we investigated the therapeutic effect of PLAG (1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol, acetylated diglyceride) in 5-fluorouracil (5-FU)-induced oral mucositis animal models. Hamsters were administered 5-FU (80 mg/kg) intraperitoneally on days 0, 6, and 9. The animals’ cheek pouches were then scratched equally with the tip of an 18-gage needle on days 1, 2, and 7. PLAG was administered daily at 250 mg/kg/day. PLAG administration significantly reduced 5-FU/scratching-induced mucositis. Dramatic reversal of weight loss in PLAG-treated hamsters with mucositis was observed. Histochemical staining data also revealed newly differentiated epidermis and blood vessels in the cheek pouches of PLAG-treated hamsters, indicative of recovery. Whole blood analyses indicated that PLAG prevents 5-FU-induced excessive neutrophil transmigration to the infection site and eventually stabilizes the number of circulating neutrophils. In a mouse mucositis model, mice with 5-FU-induced disease treated with PLAG exhibited resistance to body-weight loss compared with mice that received 5-FU or 5-FU/scratching alone. PLAG also dramatically reversed mucositis-associated weight loss and inhibited mucositis-induced inflammatory responses in the tongue and serum. These data suggest that PLAG enhances recovery from 5-FU-induced oral mucositis and may therefore be a useful therapeutic agent for treating side effects of chemotherapy, such as mucositis and cachexia. PMID:27800302

  18. Clinical assessment of oral mucositis and candidiasis compare to chemotherapic nadir in transplanted patients.

    PubMed

    Patussi, Cleverson; Sassi, Laurindo Moacir; Munhoz, Eduardo Ciliao; Zanicotti, Roberta Targa Stramandinoli; Schussel, Juliana Lucena

    2014-01-01

    Oral mucositis is a chief complication in patients undergoing hematopoietic stem cell transplantation (HSCT). It is considered a toxic inflammatory reaction that interferes with the patient's recuperation and quality of life. Oral candidiasis is a common fungal infection observed in dental practice, particularly in immunocompromised patients. The aim of this study was to evaluate the presence of oral mucositis and oral candidiasis in patients who underwent HSCT and their correlation with the chemotherapeutic nadir (lowest possible outcome). We evaluated patients with different diagnoses who underwent HSCT at the Hospital Erasto Gaertner. No chemotherapeutic nadir curves could be associated with mucositis, and patients had different presentations of mucositis. No patient developed oral candidiasis during hospitalization. Together with cell counts, we collected demographic data including age, oral hygiene, habits harmful to health, and the use of oral prostheses. It was observed that patients who smoked cigarettes before hospitalization showed less mucositis, resulting in no feeding problems or other comorbid conditions due to the effect of mucositis. However, the nadir of the chemotherapy curve, in isolation, is not a predictive tool for the appearance (or no appearance) of oral mucositis.

  19. Isoniazid Induced Lupus Presenting as Oral Mucosal Ulcers with Pancytopenia

    PubMed Central

    Ankale, Padmaraj; Sinha, Kanishk; Iyer, Aparna; Jayalakshmi, T.K

    2016-01-01

    Drug Induced Lupus Erythematous (DILE) is a rare adverse reaction to a large variety of drugs including Isoniazid (INH), with features resembling idiopathic Systemic Lupus Erythematosus (SLE). Diagnosis require identification of a temporal relationship between drug administered and symptom. It is an idiosyncratic reaction, with no pre-existing lupus. Our case highlights a rare presentation of isoniazid induced lupus with profound pancytopenia and mucosal ulcers, thus posing a diagnostic challenge. The patient was on multidrug treatment for pulmonary and knee joint tuberculosis. DILE was diagnosed on basis of strongly positive Anti Nuclear Antibodies (ANA), anti ds DNA and antihistone antibodies with clinical response to cessation of INH. PMID:27891378

  20. Determination of hydrogen peroxide concentrations by flow injection analysis based on the enhanced chemiluminescent reaction using peroxidase

    SciTech Connect

    Eremin, S.A.; Vlasenko, S.B.; Osipov, A.P.; Eremina, I.D.; Egerov, A.M. )

    1989-01-01

    The technique of flow injection analysis was employed in the determination of hydrogen peroxide. The method was based on the chemiluminescence reaction of luminol with H{sub 2}O{sub 2} which is catalyzed by horseradish peroxidase and enhanced by p-iodophenol. Hydrogen peroxide was linearly detected in the range 10{sup {minus}6}M-10{sup {minus}4}M by measuring the maximum intensity of light emitted. The detection limit is about 1 10{sup {minus}6}M hydrogen peroxide. Transition metal cations at millimolar concentrations do not have any interference on the determination of hydrogen peroxide by FIA based on the enhanced chemiluminescent reaction. This technique is relatively rapid and simple, and permits measurement of up to 80 samples/hr using generally available equipment.

  1. Communication: The origin of rotational enhancement effect for the reaction of H2O+ + H2 (D2)

    NASA Astrophysics Data System (ADS)

    Li, Anyang; Li, Yongle; Guo, Hua; Lau, Kai-Chung; Xu, Yuntao; Xiong, Bo; Chang, Yih-Chung; Ng, C. Y.

    2014-01-01

    We have measured the absolute integral cross sections (σ's) for H3O+ formed by the reaction of rovibrationally selected H2O+(X2B1; v1+v2+v3+ = 000; N+Ka+Kc+ = 000, 111, and 211) ion with H2 at the center-of-mass collision energy (Ecm) range of 0.03-10.00 eV. The σ(000), σ(111), and σ(211) values thus obtained reveal rotational enhancements at low Ecm < 0.50 eV, in agreement with the observation of the previous study of the H2O+(X2B1) + D2 reaction. This Communication presents important progress concerning the high-level ab initio quantum calculation of the potential energy surface for the H2O+(X2B1) + H2 (D2) reactions, which has provided valuable insight into the origin of the rotational enhancement effect. Governed by the charge and dipole-induced-multipole interactions, the calculation shows that H2 (D2) approaches the H end of H2O+(X2B1) in the long range, whereas chemical force in the short range favors the orientation of H2 (D2) toward the O side of H2O+. The reorientation of H2O+ reactant ion facilitated by rotational excitation thus promotes the H2O+ + H2 (D2) reaction along the minimum energy pathway, rendering the observed rotational enhancement effects. The occurrence of this effect at low Ecm indicates that the long range charge and dipole-induced-multipole interactions of the colliding pair play a significant role in the dynamics of the exothermic H2O+ + H2 (D2) reactions.

  2. Reaction enhanced channelised fluid-flux along mid- crustal shear zone: An example from Mesoproterozoic Phulad Shear Zone, Rajasthan, India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sadhana M.; Choudhury, Manideepa Roy; Das, Subhrajyoti

    2016-10-01

    Fluid infiltration at great depth during regional metamorphism plays a major role in mass transport and is responsible for significant rheological changes in the rock. Calc-silicate rocks of the Kajalbas area of Delhi Fold Belt, Rajasthan, are characterised by foliation parallel alternate bands of amphibole-rich and clinopyroxene-plagioclase feldspar-rich layers of varying thicknesses (mm to decimetre thick). Textural relation suggests that the amphibole grains formed from clinopyroxene and plagioclase in the late phase of regional deformation. Algebraic analysis of the reaction textures and mineral compositions was performed with the computer program C-Space to obtain the balanced chemical reactions that led to the formation of amphibole-rich bands. The computed balanced reaction is 70.74 Clinopyroxene + 27.23 Plagioclase + 22.018 H2O + 5.51 K++ 1.00 Mg2++ 27.15 Fe2+ = 22.02 Amphibole + 67.86 SiO2 aqueous + 36.42 Ca2++ 8.98 Na+. The constructed reaction suggests that aqueous fluid permeated the calc-silicate rock along mm to decimetre thick channels, metasomatized the clinopyroxene-plagioclase bearing rocks to form the amphibole-rich layers. The regional deformation presumably created the fluid channels thereby allowing the metasomatic fluid to enter the rock system. The above reaction has large negative volume change for solid phases indicating reaction-induced permeability. Thermodynamic calculations suggest that the fluid-rock interaction occurred at 665 ±05∘C and 6.6 ±0.25 kbar (corresponding to ˜20 km depth). Textural modeling integrating the textural features and balanced chemical reaction of the calc-silicate rocks of Mesoproterozoic Phulad Shear Zone thus indicate that extremely channelled fluid flow was reaction enhanced and caused major change in the rock rheology.

  3. A model SN2 reaction ‘on water’ does not show rate enhancement

    NASA Astrophysics Data System (ADS)

    Nelson, Katherine V.; Benjamin, Ilan

    2011-05-01

    Molecular dynamics calculations of the benchmark nucleophilic substitution reaction (SN2) Cl- + CH3Cl are carried out at the water liquid/vapor interface. The reaction free energy profile and the activation free energy are determined as a function of the reactants' location normal to the surface. The activation free energy remains almost constant relative to that in bulk water, despite the fact that the barrier is expected to significantly decrease as the reaction is carried out near the vapor phase. We show that this is due to the combined effects of a clustering of water molecules around the nucleophile and a relatively weak hydration of the transition state.

  4. Low degree metabolites explain essential reactions and enhance modularity in biological networks

    PubMed Central

    Samal, Areejit; Singh, Shalini; Giri, Varun; Krishna, Sandeep; Raghuram, Nandula; Jain, Sanjay

    2006-01-01

    Background Recently there has been a lot of interest in identifying modules at the level of genetic and metabolic networks of organisms, as well as in identifying single genes and reactions that are essential for the organism. A goal of computational and systems biology is to go beyond identification towards an explanation of specific modules and essential genes and reactions in terms of specific structural or evolutionary constraints. Results In the metabolic networks of Escherichia coli, Saccharomyces cerevisiae and Staphylococcus aureus, we identified metabolites with a low degree of connectivity, particularly those that are produced and/or consumed in just a single reaction. Using flux balance analysis (FBA) we also determined reactions essential for growth in these metabolic networks. We find that most reactions identified as essential in these networks turn out to be those involving the production or consumption of low degree metabolites. Applying graph theoretic methods to these metabolic networks, we identified connected clusters of these low degree metabolites. The genes involved in several operons in E. coli are correctly predicted as those of enzymes catalyzing the reactions of these clusters. Furthermore, we find that larger sized clusters are over-represented in the real network and are analogous to a 'network motif. Using FBA for the above mentioned three organisms we independently identified clusters of reactions whose fluxes are perfectly correlated. We find that the composition of the latter 'functional clusters' is also largely explained in terms of clusters of low degree metabolites in each of these organisms. Conclusion Our findings mean that most metabolic reactions that are essential can be tagged by one or more low degree metabolites. Those reactions are essential because they are the only ways of producing or consuming their respective tagged metabolites. Furthermore, reactions whose fluxes are strongly correlated can be thought of as 'glued

  5. Mucosal disease series. Number IV. Erythema multiforme.

    PubMed

    Farthing, P; Bagan, J-V; Scully, C

    2005-09-01

    Erythema multiforme (EM) is an acute mucocutaneous hypersensitivity reaction characterised by a skin eruption, with or without oral or other mucous membrane lesions. Occasionally EM may involve the mouth alone. EM has been classified into a number of different variants based on the degree of mucosal involvement and the nature and distribution of the skin lesions. EM minor typically affects no more than one mucosa, is the most common form and may be associated with symmetrical target lesions on the extremities. EM major is more severe, typically involving two or more mucous membranes with more variable skin involvement - which is used to distinguish it from Stevens-Johnson syndrome (SJS), where there is extensive skin involvement and significant morbidity and a mortality rate of 5-15%. Both EM major and SJS can involve internal organs and typically are associated with systemic symptoms. Toxic epidermal necrolysis (TEN) may be a severe manifestation of EM, but some experts regard it as a discrete disease. EM can be triggered by a number of factors, but the best documented is preceding infection with herpes simplex virus (HSV), the lesions resulting from a cell mediated immune reaction triggered by HSV-DNA. SJS and TEN are usually initiated by drugs, and the tissue damage is mediated by soluble factors including Fas and FasL.

  6. Cage-bell Pt-Pd nanostructures with enhanced catalytic properties and superior methanol tolerance for oxygen reduction reaction

    PubMed Central

    Chen, Dong; Ye, Feng; Liu, Hui; Yang, Jun

    2016-01-01

    Precisely tailoring the structure and fully making use of the components of nanoparticles are effective to enhance their catalytic performance for a given reaction. We herein demonstrate the design of cage-bell structured Pt-Pd nanoparticles, where a Pd shell is deliberately selected to enhance the catalytic property and methanol tolerance of Pt for oxygen reduction reaction. This strategy starts with the synthesis of core-shell Pt@Ag nanoparticles, followed by galvanic replacement reaction between the Ag shell and Pd2+ ions to form core-shell-shell Pt@Ag@Ag-Pd nanoparticles with a Pt core and double shells composed of Ag at inner and alloy Ag-Pd at outer, respectively. Then, the core-shell-shell templates are agitated with saturated NaCl solution to eliminate the Ag component from the double shells, leading to the formation of bimetallic Pt-Pd nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a porous Pd shell, which show enhanced catalytic activity for oxygen reduction compared with that of the Pt seeds due to the additional catalysis from Pd shell. In addition, owing to the different diffusion behavior of methanol and oxygen molecules in the porous Pd shell, the Pt-Pd cage-bell nanostructures also exhibit superior methanol tolerant property in catalyzing the oxygen reduction. PMID:27079897

  7. Plasmon-Enhanced Enzymatic Reactions: A Study of Nanoparticle-Enzyme Distance- and Nanoparticle Loading-Dependent Enzymatic Activity

    PubMed Central

    Abel, Biebele; Akinsule, Alice; Andrews, Canisha; Aslan, Kadir

    2011-01-01

    A detailed investigation of the dependence of the efficiency of plasmon-enhanced enzymatic reactions on the distance between silver island films (SIFs) and horse radish peroxidase (HRP) enzyme and on the loading of SIFs on glass surfaces is presented. Three different extent of loading of SIFs on glass slides were used: 1) low, 2) medium and 3) high, which was characterized by using optical absorption spectroscopy and scanning electron microscopy. Streptavidin-linked HRP enzyme was deposited onto SIFs and glass slides by using three different strategies: strategy 1: biotin-avidin protein assay (distance between SIFs and HRP = 4–8 nm), strategy 2: self assembled monolayers (SAMs) (1–5 nm), strategy 3: polymer layer (1–5 nm). The efficiency of enzymatic conversion of O-phenylenediamine dihydrochloride (OPD) to a colored product by HRP on SIFs and glass surfaces was assessed by optical absorption spectroscopy. The distance between SIFs and HRP and the extent of loading of SIFs on the glass surfaces were shown to have significant effect on the efficiency of plasmon-enhanced enzymatic reactions. In this regard, up to an %250 increase in enzymatic conversion of OPD was observed from SIFs with high loading using strategy 1. In addition, we have studied the potential of repeated use of SIFs in plasmon-enhanced enzymatic reactions. PMID:21949594

  8. Plasmon-Enhanced Enzymatic Reactions: A Study of Nanoparticle-Enzyme Distance- and Nanoparticle Loading-Dependent Enzymatic Activity.

    PubMed

    Abel, Biebele; Akinsule, Alice; Andrews, Canisha; Aslan, Kadir

    2011-01-01

    A detailed investigation of the dependence of the efficiency of plasmon-enhanced enzymatic reactions on the distance between silver island films (SIFs) and horse radish peroxidase (HRP) enzyme and on the loading of SIFs on glass surfaces is presented. Three different extent of loading of SIFs on glass slides were used: 1) low, 2) medium and 3) high, which was characterized by using optical absorption spectroscopy and scanning electron microscopy. Streptavidin-linked HRP enzyme was deposited onto SIFs and glass slides by using three different strategies: strategy 1: biotin-avidin protein assay (distance between SIFs and HRP = 4-8 nm), strategy 2: self assembled monolayers (SAMs) (1-5 nm), strategy 3: polymer layer (1-5 nm). The efficiency of enzymatic conversion of O-phenylenediamine dihydrochloride (OPD) to a colored product by HRP on SIFs and glass surfaces was assessed by optical absorption spectroscopy. The distance between SIFs and HRP and the extent of loading of SIFs on the glass surfaces were shown to have significant effect on the efficiency of plasmon-enhanced enzymatic reactions. In this regard, up to an %250 increase in enzymatic conversion of OPD was observed from SIFs with high loading using strategy 1. In addition, we have studied the potential of repeated use of SIFs in plasmon-enhanced enzymatic reactions.

  9. Cage-bell Pt-Pd nanostructures with enhanced catalytic properties and superior methanol tolerance for oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Ye, Feng; Liu, Hui; Yang, Jun

    2016-04-01

    Precisely tailoring the structure and fully making use of the components of nanoparticles are effective to enhance their catalytic performance for a given reaction. We herein demonstrate the design of cage-bell structured Pt-Pd nanoparticles, where a Pd shell is deliberately selected to enhance the catalytic property and methanol tolerance of Pt for oxygen reduction reaction. This strategy starts with the synthesis of core-shell Pt@Ag nanoparticles, followed by galvanic replacement reaction between the Ag shell and Pd2+ ions to form core-shell-shell Pt@Ag@Ag-Pd nanoparticles with a Pt core and double shells composed of Ag at inner and alloy Ag-Pd at outer, respectively. Then, the core-shell-shell templates are agitated with saturated NaCl solution to eliminate the Ag component from the double shells, leading to the formation of bimetallic Pt-Pd nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a porous Pd shell, which show enhanced catalytic activity for oxygen reduction compared with that of the Pt seeds due to the additional catalysis from Pd shell. In addition, owing to the different diffusion behavior of methanol and oxygen molecules in the porous Pd shell, the Pt-Pd cage-bell nanostructures also exhibit superior methanol tolerant property in catalyzing the oxygen reduction.

  10. Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Wegeng, Robert S [Richland, WA; Gao, Yufei [Kennewick, WA

    2003-04-01

    The present invention is a method and apparatus (vessel) for providing a heat transfer rate from a reaction chamber through a wall to a heat transfer chamber substantially matching a local heat transfer rate of a catalytic thermal chemical reaction. The key to the invention is a thermal distance defined on a cross sectional plane through the vessel inclusive of a heat transfer chamber, reaction chamber and a wall between the chambers. The cross sectional plane is perpendicular to a bulk flow direction of the reactant stream, and the thermal distance is a distance between a coolest position and a hottest position on the cross sectional plane. The thermal distance is of a length wherein the heat transfer rate from the reaction chamber to the heat transfer chamber substantially matches the local heat transfer rate.

  11. Enhanced electrocatalysis of the oxygen reduction reaction based on pattering of platinum surfaces with cyanide.

    SciTech Connect

    Strmcnik, D.; Escudero-Escribano, M.; Kodama, K.; Stamenkovic, V. R.; Cuesta, A.; Markovic, N. M.; Materials Science Division; Inst. de Quimica Fisica; Toyota Central R&D Labs., Inc.

    2010-08-15

    The slow rate of the oxygen reduction reaction in the phosphoric acid fuel cell is the main factor limiting its wide application. Here, we present an approach that can be used for the rational design of cathode catalysts with potential use in phosphoric acid fuel cells, or in any environments containing strongly adsorbing tetrahedral anions. This approach is based on molecular patterning of platinum surfaces with cyanide adsorbates that can efficiently block the sites for adsorption of spectator anions while the oxygen reduction reaction proceeds unhindered. We also demonstrate that, depending on the supporting electrolyte anions and cations, on the same CN-covered Pt(111) surface, the oxygen reduction reaction activities can range from a 25-fold increase to a 50-fold decrease. This behaviour is discussed in the light of the role of covalent and non-covalent interactions in controlling the ensemble of platinum active sites required for high turn over rates of the oxygen reduction reaction.

  12. Enhanced electrocatalysis of the oxygen reduction reaction based on patterning of platinum surfaces with cyanide

    SciTech Connect

    Strmcnik, D.; Escudero, M.; Kodama, K.; Stamenkovic, V. R.; Cuesta, A.; Markovic, N. M.

    2010-10-01

    The slow rate of the oxygen reduction reaction in the phosphoric acid fuel cell is the main factor limiting its wide application. Here, we present an approach that can be used for the rational design of cathode catalysts with potential use in phosphoric acid fuel cells, or in any environments containing strongly adsorbing tetrahedral anions. This approach is based on molecular patterning of platinum surfaces with cyanide adsorbates that can efficiently block the sites for adsorption of spectator anions while the oxygen reduction reaction proceeds unhindered. We also demonstrate that, depending on the supporting electrolyte anions and cations, on the same CN-covered Pt(111) surface, the oxygen reduction reaction activities can range from a 25-fold increase to a 50-fold decrease. This behaviour is discussed in the light of the role of covalent and non-covalent interactions in controlling the ensemble of platinum active sites required for high turn over rates of the oxygen reduction reaction.

  13. Reaction mechanisms and rate constants of waste degradation in landfill bioreactor systems with enzymatic-enhancement.

    PubMed

    Jayasinghe, P A; Hettiaratchi, J P A; Mehrotra, A K; Kumar, S

    2014-06-01

    Augmenting leachate before recirculation with peroxidase enzymes is a novel method to increase the available carbon, and therefore the food supply to microorganisms at the declining phase of the anaerobic landfill bioreactor operation. In order to optimize the enzyme-catalyzed leachate recirculation process, it is necessary to identify the reaction mechanisms and determine rate constants. This paper presents a kinetic model developed to ascertain the reaction mechanisms and determine the rate constants for enzyme catalyzed anaerobic waste degradation. The maximum rate of reaction (Vmax) for MnP enzyme-catalyzed reactors was 0.076 g(TOC)/g(DS).day. The catalytic turnover number (k(cat)) of the MnP enzyme-catalyzed was 506.7 per day while the rate constant (k) of the un-catalyzed reaction was 0.012 per day. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. The Development of an AIDS Mucosal Vaccine

    PubMed Central

    Tang, Xian; Chen, Zhiwei

    2010-01-01

    It is well known that mucosal tissues contain the largest surface area of the human body and are the front line of natural host defense against various pathogens. In fact, more than 80% of infectious disease pathogens probably gain entry into the susceptible human hosts through open mucosal surfaces. Human immunodeficiency virus type one (HIV-1), a mainly sexually transmitted virus, also primarily targets the vaginal and gastrointestinal mucosa as entry sites for viral transmission, seeding, replication and amplification. Since HIV-1 establishes its early replication in vaginal or rectal mucosal tissues, the induction of sufficient mucosal immunity at the initial site of HIV-1 transmission becomes essential for a protective vaccine. However, despite the fact that current conventional vaccine strategies have remained unsuccessful in preventing HIV-1 infection, sufficient financial support and resources have yet to be given to develop a vaccine able to elicit protective mucosal immunity against sexual transmissions. Interestingly, Chinese ancestors invented variolation through intranasal administration about one thousand years ago, which led to the discovery of a successful smallpox vaccine and the final eradication of the disease. It is the hope for all mankind that the development of a mucosal AIDS vaccine will ultimately help control the AIDS pandemic. In order to discover an effective mucosal AIDS vaccine, it is necessary to have a deep understanding of mucosal immunology and to test various mucosal vaccination strategies. PMID:21994611

  15. Reaction time as a measure of enhanced blue-light mediated cognitive function following cataract surgery.

    PubMed

    Schmoll, Conrad; Tendo, Christelle; Aspinall, Peter; Dhillon, Bal

    2011-12-01

    Since 2002 the discovery of a novel population of intrinsically photosensitive retinal ganglion cells, expressing the photopigment melanopsin, has attracted broad interest in human blue-light mediated non-visual effects including circadian regulation and cognitive function. Ageing is associated with insomnia and cognitive decline. It has been postulated that reduced blue-light transmission through the formation of cataract impairs melanopsin dependant non-visual brain responses mediated by intrinsically photosensitive retinal ganglion cells. We aimed to establish if any objective improvement in cognition could be demonstrated using a reaction time task (RTT) following cataract surgery and intraocular lens implantation. Following strict inclusion and exclusion criteria, 15 patients (age range 59-87, mean 75.4 years) with bilateral cataract performed the RTT before and after surgery on one eye. The mean and the SD of two modalities of reaction time, namely complex reaction time and simple reaction time, were measured and analysed. Responses became both quicker and more consistent following surgery, with statistically significant improvements in the complex reaction time (p=0.016) and the complex reaction time SD (p=0.055), which were not due to a learning effect or improved vision. The results suggest that improved blue-light transmission following cataract surgery has a beneficial effect on cognitive function. We advocate the RTT as an objective platform for exploring these benefits in large sample randomised controlled trials.

  16. Voice Disorders in Mucosal Leishmaniasis

    PubMed Central

    Ruas, Ana Cristina Nunes; Lucena, Márcia Mendonça; da Costa, Ananda Dutra; Vieira, Jéssica Rafael; de Araújo-Melo, Maria Helena; Terceiro, Benivaldo Ramos Ferreira; de Sousa Torraca, Tania Salgado; de Oliveira Schubach, Armando; Valete-Rosalino, Claudia Maria

    2014-01-01

    Introduction Leishmaniasis is considered as one of the six most important infectious diseases because of its high detection coefficient and ability to produce deformities. In most cases, mucosal leishmaniasis (ML) occurs as a consequence of cutaneous leishmaniasis. If left untreated, mucosal lesions can leave sequelae, interfering in the swallowing, breathing, voice and speech processes and requiring rehabilitation. Objective To describe the anatomical characteristics and voice quality of ML patients. Materials and Methods A descriptive transversal study was conducted in a cohort of ML patients treated at the Laboratory for Leishmaniasis Surveillance of the Evandro Chagas National Institute of Infectious Diseases - Fiocruz, between 2010 and 2013. The patients were submitted to otorhinolaryngologic clinical examination by endoscopy of the upper airways and digestive tract and to speech-language assessment through directed anamnesis, auditory perception, phonation times and vocal acoustic analysis. The variables of interest were epidemiologic (sex and age) and clinic (lesion location, associated symptoms and voice quality. Results 26 patients under ML treatment and monitored by speech therapists were studied. 21 (81%) were male and five (19%) female, with ages ranging from 15 to 78 years (54.5+15.0 years). The lesions were distributed in the following structures 88.5% nasal, 38.5% oral, 34.6% pharyngeal and 19.2% laryngeal, with some patients presenting lesions in more than one anatomic site. The main complaint was nasal obstruction (73.1%), followed by dysphonia (38.5%), odynophagia (30.8%) and dysphagia (26.9%). 23 patients (84.6%) presented voice quality perturbations. Dysphonia was significantly associated to lesions in the larynx, pharynx and oral cavity. Conclusion We observed that vocal quality perturbations are frequent in patients with mucosal leishmaniasis, even without laryngeal lesions; they are probably associated to disorders of some resonance

  17. Developments in the production of mucosal antibodies in plants.

    PubMed

    Vasilev, Nikolay; Smales, C Mark; Schillberg, Stefan; Fischer, Rainer; Schiermeyer, Andreas

    2016-01-01

    Recombinant mucosal antibodies represent attractive target molecules for the development of next generation biopharmaceuticals for passive immunization against various infectious diseases and treatment of patients suffering from mucosal antibody deficiencies. As these polymeric antibodies require complex post-translational modifications and correct subunit assembly, they are considered as difficult-to-produce recombinant proteins. Beside the traditional, mammalian-based production platforms, plants are emerging as alternative expression hosts for this type of complex macromolecule. Plant cells are able to produce high-quality mucosal antibodies as shown by the successful expression of the secretory immunoglobulins A (IgA) and M (IgM) in various antibody formats in different plant species including tobacco and its close relative Nicotiana benthamiana, maize, tomato and Arabidopsis thaliana. Importantly for biotherapeutic application, transgenic plants are capable of synthesizing functional IgA and IgM molecules with biological activity and safety profiles comparable with their native mammalian counterparts. This article reviews the structure and function of mucosal IgA and IgM antibodies and summarizes the current knowledge of their production and processing in plant host systems. Specific emphasis is given to consideration of intracellular transport processes as these affect assembly of the mature immunoglobulins, their secretion rates, proteolysis/degradation and glycosylation patterns. Furthermore, this review provides an outline of glycoengineering efforts that have been undertaken so far to produce antibodies with homogenous human-like glycan decoration. We believe that the continued development of our understanding of the plant cellular machinery related to the heterologous expression of immunoglobulins will further improve the production levels, quality and control of post-translational modifications that are 'human-like' from plant systems and enhance the

  18. Colonic mucosal mediators from patients with irritable bowel syndrome excite enteric cholinergic motor neurons.

    PubMed

    Balestra, B; Vicini, R; Cremon, C; Zecchi, L; Dothel, G; Vasina, V; De Giorgio, R; Paccapelo, A; Pastoris, O; Stanghellini, V; Corinaldesi, R; De Ponti, F; Tonini, M; Barbara, G

    2012-12-01

    Mediators released in the mucosal milieu have been suggested to be involved in visceral hypersensitivity and abdominal pain in patients with irritable bowel syndrome (IBS). However, their impact on myenteric neurons remains unsettled. Mucosal biopsies were obtained from the descending colon of patients with IBS and controls. Mucosal mast cells were identified immunohistochemically. The impact of spontaneously released mucosal mediators on guinea pig electrically stimulated longitudinal muscle myenteric plexus (LMMP) preparations was assessed in vitro by means of selective receptor antagonists and inhibitors. Patients with IBS showed an increased mast cell count compared with controls. Application of mucosal mediators of IBS to LMMPs potentiated cholinergic twitch contractions, an effect directly correlated with mast cell counts. Enhanced contractions were inhibited by 50.3% with the prostaglandin D2 antagonist BW A868C, by 31.3% and 39% with the TRPV1 antagonists capsazepine and HC-030031, respectively, and by 60.5% with purinergic P2X antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid. Conversely, the serotonin1-4, histamine1-3, tachykinin1-3 receptor blockade, and serine protease inhibition had no significant effect. Colonic mucosal mediators from patients with IBS excite myenteric cholinergic motor neurons. These effects were correlated with mast cell counts and mediated by activation of prostanoid receptors, TRPV1, and P2X receptors. These results support the role of mucosal inflammatory mediators and mast cell activation in altered motor function of IBS. © 2012 Blackwell Publishing Ltd.

  19. Mucosal Vaccination Overcomes the Barrier to Recombinant Vaccinia Immunization Caused by Preexisting Poxvirus Immunity

    NASA Astrophysics Data System (ADS)

    Belyakov, Igor M.; Moss, Bernard; Strober, Warren; Berzofsky, Jay A.

    1999-04-01

    Overcoming preexisting immunity to vaccinia virus in the adult population is a key requirement for development of otherwise potent recombinant vaccinia vaccines. Based on our observation that s.c. immunization with vaccinia induces cellular and antibody immunity to vaccinia only in systemic lymphoid tissue and not in mucosal sites, we hypothesized that the mucosal immune system remains naive to vaccinia and therefore amenable to immunization with recombinant vaccinia vectors despite earlier vaccinia exposure. We show that mucosal immunization of vaccinia-immune BALB/c mice with recombinant vaccinia expressing HIV gp160 induced specific serum antibody and strong HIV-specific cytotoxic T lymphocyte responses. These responses occurred not only in mucosal but also in systemic lymphoid tissue, whereas systemic immunization was ineffective under these circumstances. In this context, intrarectal immunization was more effective than intranasal immunization. Boosting with a second dose of recombinant vaccinia was also more effective via the mucosal route. The systemic HIV-specific cytotoxic T lymphocyte response was enhanced by coadministration of IL-12 at the mucosal site. These results also demonstrate the independent compartmentalization of the mucosal versus systemic immune systems and the asymmetric trafficking of lymphocytes between them. This approach to circumvent previous vaccinia immunity may be useful for induction of protective immunity against infectious diseases and cancer in the sizable populations with preexisting immunity to vaccinia from smallpox vaccination.

  20. Characterization of mucosal biofilms on human adenoid tissues.

    PubMed

    Kania, Romain E; Lamers, Gerda E M; Vonk, Marcel J; Dorpmans, Esmee; Struik, Joyce; Tran Ba Huy, Patrice; Hiemstra, Pieter; Bloemberg, Guido V; Grote, Jan J

    2008-01-01

    To demonstrate the presence of mucosal biofilm in adenoid tissue using double staining for visualization of both the bacterial matrix and the bacterial cells. To identify bacterial species present on the surface of the studied adenoids. Prospective study. A total of 39 specimens of adenoidectomy were removed from children with chronic and/or recurrent otitis media. The specimens were prepared for light microscopy using Gram staining, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Double staining was performed with CLSM to visualize both the bacteria and the glycocalyx matrix. Nine adenoids on which bacterial biofilms were visualized with CLSM were used for identification of bacterial species by 16S-DNA polymerase chain reaction (PCR) amplification and homology analysis. Of the 39 adenoids investigated, 22 (54%) showed evidence of mucosal biofilms. Gram staining, SEM and CLSM showed the presence of bacterial cells, organized in bacterial microcolonies. CLSM with double staining demonstrated mucosal biofilms by showing the presence of both bacteria and the glycocalyx. The use of 16S-DNA polymerase chain reaction (PCR) amplification and subsequent sequence analyses identified the presence of Corynebacterium argentoratense, Streptococcus salivarius, Micrococcus luteus, and Staphylococcus aureus. This study demonstrates that adenoid tissue in children with chronic or/and recurrent otitis media contains mucosal biofilms in 54% of the cases. The existence of living bacteria has been demonstrated. Further studies are required to describe the panel of bacteria that can be harbored in the biofilms present in adenoids and the mechanisms involved in the physiopathology of otitis prone children.

  1. Interfacial engineering of MoS2/TiO2 hybrids for enhanced electrocatalytic hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Song, Xiaolin; Chen, Guifeng; Guan, Lixiu; Zhang, Hui; Tao, Junguang

    2016-09-01

    Herein, we show that the synergistic effect between MoS2 and TiO2 enhances the hydrogen evolution reaction (HER) performance of their hybrids, which is tunable via interface engineering. Among several interfaces, MoS2/TiO2-H complexes exhibit the best HER activity. The observed Tafel slope of 66.9 mV/dec is well in range of previous literature reports, suggesting a Volmer-Heyrovsky mechanism. Enhanced activities were attributed to abundant active sites at the interfaces, as well as improved charge transfer efficiency. Our results emphasize the roles that interfaces play in enhancing the HER activities of MoS2-based heterogeneous catalysts.

  2. Mucosal immunity and probiotics in fish.

    PubMed

    Lazado, Carlo C; Caipang, Christopher Marlowe A

    2014-07-01

    Teleost mucosal immunity has become the subject of unprecedented research studies in recent years because of its diversity and defining characteristics. Its immune repertoire is governed by the mucosa-associated lymphoid tissues (MALT) which are divided into gut-associated lymphoid tissues (GALT), skin-associated lymphoid tissues (SALT), and gill-associated lymphoid tissues (GIALT). The direct contact with its immediate environment makes the mucosal surfaces of fish susceptible to a wide variety of pathogens. The inherent immunocompetent cells and factors in the mucosal surfaces together with the commensal microbiota have pivotal role against pathogens. Immunomodulation is a popular prophylactic strategy in teleost and probiotics possess this beneficial feature. Most of the studies on the immunomodulatory properties of probiotics in fish mainly discussed their impacts on systemic immunity. In contrast, few of these studies discussed the immunomodulatory features of probiotics in mucosal surfaces and are concentrated on the influences in the gut. Significant attention should be devoted in understanding the relationship of mucosal immunity and probiotics as the present knowledge is limited and are mostly based on extrapolations of studies in humans and terrestrial vertebrates. In the course of the advancement of mucosal immunity and probiotics, new perspectives in probiotics research, e.g., probiogenomics have emerged. This review affirms the relevance of probiotics in the mucosal immunity of fish by revisiting and bridging the current knowledge on teleost mucosal immunity, mucosal microbiota and immunomodulation of mucosal surfaces by probiotics. Expanding the knowledge of immunomodulatory properties of probiotics especially on mucosal immunity is essential in advancing the use of probiotics as a sustainable and viable strategy for successful fish husbandry.

  3. Choice and Design of Adjuvants for Parenteral and Mucosal Vaccines

    PubMed Central

    Savelkoul, Huub F. J.; Ferro, Valerie A.; Strioga, Marius M.; Schijns, Virgil E. J. C.

    2015-01-01

    The existence of pathogens that escape recognition by specific vaccines, the need to improve existing vaccines and the increased availability of therapeutic (non-infectious disease) vaccines necessitate the rational development of novel vaccine concepts based on the induction of protective cell-mediated immune responses. For naive T-cell activation, several signals resulting from innate and adaptive interactions need to be integrated, and adjuvants may interfere with some or all of these signals. Adjuvants, for example, are used to promote the immunogenicity of antigens in vaccines, by inducing a pro-inflammatory environment that enables the recruitment and promotion of the infiltration of phagocytic cells, particularly antigen-presenting cells (APC), to the injection site. Adjuvants can enhance antigen presentation, induce cytokine expression, activate APC and modulate more downstream adaptive immune reactions (vaccine delivery systems, facilitating immune Signal 1). In addition, adjuvants can act as immunopotentiators (facilitating Signals 2 and 3) exhibiting immune stimulatory effects during antigen presentation by inducing the expression of co-stimulatory molecules on APC. Together, these signals determine the strength of activation of specific T-cells, thereby also influencing the quality of the downstream T helper cytokine profiles and the differentiation of antigen-specific T helper populations (Signal 3). New adjuvants should also target specific (innate) immune cells in order to facilitate proper activation of downstream adaptive immune responses and homing (Signal 4). It is desirable that these adjuvants should be able to exert such responses in the context of mucosal administered vaccines. This review focuses on the understanding of the potential working mechanisms of the most well-known classes of adjuvants to be used effectively in vaccines. PMID:26344951

  4. Choice and Design of Adjuvants for Parenteral and Mucosal Vaccines.

    PubMed

    Savelkoul, Huub F J; Ferro, Valerie A; Strioga, Marius M; Schijns, Virgil E J C

    2015-03-05

    The existence of pathogens that escape recognition by specific vaccines, the need to improve existing vaccines and the increased availability of therapeutic (non-infectious disease) vaccines necessitate the rational development of novel vaccine concepts based on the induction of protective cell-mediated immune responses. For naive T-cell activation, several signals resulting from innate and adaptive interactions need to be integrated, and adjuvants may interfere with some or all of these signals. Adjuvants, for example, are used to promote the immunogenicity of antigens in vaccines, by inducing a pro-inflammatory environment that enables the recruitment and promotion of the infiltration of phagocytic cells, particularly antigen-presenting cells (APC), to the injection site. Adjuvants can enhance antigen presentation, induce cytokine expression, activate APC and modulate more downstream adaptive immune reactions (vaccine delivery systems, facilitating immune Signal 1). In addition, adjuvants can act as immunopotentiators (facilitating Signals 2 and 3) exhibiting immune stimulatory effects during antigen presentation by inducing the expression of co-stimulatory molecules on APC. Together, these signals determine the strength of activation of specific T-cells, thereby also influencing the quality of the downstream T helper cytokine profiles and the differentiation of antigen-specific T helper populations (Signal 3). New adjuvants should also target specific (innate) immune cells in order to facilitate proper activation of downstream adaptive immune responses and homing (Signal 4). It is desirable that these adjuvants should be able to exert such responses in the context of mucosal administered vaccines. This review focuses on the understanding of the potential working mechanisms of the most well-known classes of adjuvants to be used effectively in vaccines.

  5. Modulation of gut mucosal biofilms.

    PubMed

    Kleessen, Brigitta; Blaut, Michael

    2005-04-01

    Non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. Bifidobacteria and lactobacilli are the most frequently targeted organisms. Less information exists on effects of inulin-type fructans on the composition, metabolism and health-related significance of bacteria at or near the mucosa surface or in the mucus layer forming mucosa-associated biofilms. Using rats inoculated with a human faecal flora as an experimental model we have found that inulin-type fructans in the diet modulated the gut microbiota by stimulation of mucosa-associated bifidobacteria as well as by partial reduction of pathogenic Salmonella enterica subsp. enterica serovar Typhimurium and thereby benefit health. In addition to changes in mucosal biofilms, inulin-type fructans also induced changes in the colonic mucosa stimulating proliferation in the crypts, increasing the release of mucins, and altering the profile of mucin components in the goblet cells and epithelial mucus layer. These results indicate that inulin-type fructans may stabilise the gut mucosal barrier. Dietary supplementation with these prebiotics could offer a new approach to supporting the barrier function of the mucosa.

  6. Eosinophils in mucosal immune responses

    PubMed Central

    Travers, J; Rothenberg, M E

    2015-01-01

    Eosinophils, multifunctional cells that contribute to both innate and adaptive immunity, are involved in the initiation, propagation and resolution of immune responses, including tissue repair. They achieve this multifunctionality by expression of a diverse set of activation receptors, including those that directly recognize pathogens and opsonized targets, and by their ability to store and release preformed cytotoxic mediators that participate in host defense, to produce a variety of de novo pleotropic mediators and cytokines and to interact directly and indirectly with diverse cell types, including adaptive and innate immunocytes and structural cells. Herein, we review the basic biology of eosinophils and then focus on new emerging concepts about their role in mucosal immune homeostasis, particularly maintenance of intestinal IgA. We review emerging data about their development and regulation and describe new concepts concerning mucosal eosinophilic diseases. We describe recently developed therapeutic strategies to modify eosinophil levels and function and provide collective insight about the beneficial and detrimental functions of these enigmatic cells. PMID:25807184

  7. Antimicrobials, mucosal coating agents, anesthetics, analgesics, and nutritional supplements for alimentary tract mucositis.

    PubMed

    Barasch, Andrei; Elad, Sharon; Altman, Arnold; Damato, Kathryn; Epstein, Joel

    2006-06-01

    This review focuses on the value of several groups of agents for the prevention and treatment of mucositis. The review refers to alimentary mucositis as a generalized term that includes oral mucositis and gastrointestinal mucositis. This paper is part of the systematic review made by the mucositis study group which operates in the Multinational Association of Supportive Care in Cancer (MASCC)/International Society of Oral Oncology (ISOO). Several new guidelines are suggested in this review as an update to the primary systematic review that was published by the same group in 2004.

  8. Enhancing the methanol tolerance of platinum nanoparticles for the cathode reaction of direct methanol fuel cells through a geometric design

    PubMed Central

    Feng, Yan; Ye, Feng; Liu, Hui; Yang, Jun

    2015-01-01

    Mastery over the structure of nanoparticles might be an effective way to enhance their performance for a given application. Herein we demonstrate the design of cage-bell nanostructures to enhance the methanol tolerance of platinum (Pt) nanoparticles while remaining their catalytic activity for oxygen reduction reaction. This strategy starts with the synthesis of core-shell-shell nanoparticles with Pt and silver (Ag) residing respectively in the core and inner shell regions, which are then agitated with saturated sodium chloride (NaCl) solution to eliminate the Ag component from the inner shell region, leading to the formation of bimetallic nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a metal shell with nano-channels, which exhibit superior methanol-tolerant property in catalyzing oxygen reduction reaction due to the different diffusion behaviour of methanol and oxygen in the porous metal shell of cage-bell structured nanoparticles. In particular, the use of remarkably inexpensive chemical agent (NaCl) to promote the formation of cage-bell structured particles containing a wide spectrum of metal shells highlights its engineering merit to produce highly selective electrocatalysts on a large scale for the cathode reaction of direct methanol fuel cells. PMID:26578100

  9. Surface-Enhanced Raman Spectroscopy Assisted by Radical Capturer for Tracking of Plasmon-Driven Redox Reaction

    PubMed Central

    Yan, Xuefeng; Wang, Lingzhi; Tan, Xianjun; Tian, Baozhu; Zhang, Jinlong

    2016-01-01

    The deep understanding about the photocatalytic reaction induced by the surface plasmon resonance (SPR) effect is desirable but remains a considerable challenge due to the ultrafast relaxation of hole-electron exciton from SPR process and a lack of an efficient monitoring system. Here, using the p-aminothiophenol (PATP) oxidation SPR-catalyzed by Ag nanoparticle as a model reaction, a radical-capturer-assisted surface-enhanced Raman spectroscopy (SERS) has been used as an in-situ tracking technique to explore the primary active species determining the reaction path. Hole is revealed to be directly responsible for the oxidation of PATP to p, p′-dimercaptoazobenzene (4, 4′-DMAB) and O2 functions as an electron capturer to form isolated hole. The oxidation degree of PATP can be further enhanced through a joint utilization of electron capturers of AgNO3 and atmospheric O2, producing p-nitrothiophenol (PNTP) within 10 s due to the improved hole-electron separation efficiency. PMID:27444268

  10. Twin defects engineered Pd cocatalyst on C3N4 nanosheets for enhanced photocatalytic performance in CO2 reduction reaction.

    PubMed

    Lang, Qingqing; Hu, Wenli; Zhou, Penghui; Huang, Tianlong; Zhong, Shuxian; Yang, Lining; Chen, Jianrong; Bai, Song

    2017-10-05

    Photocatalytic coversion of CO2 to value-added chemicals, a potential route to addressing the depletion of fossil fuels and anthropogenic climate change, is greatly limited by the low-efficient semiconductor photocatalyst. The integration of cocatalyst with light-harvesting semiconductor is a promising approach to enhancing the photocatalytic performance in CO2 reduction reaction. The enhancement is greatly determined by the catalytic active sites on the surface of cocatalyst. Herein, we demonstrate that the photocatalytic performance in the CO2 reduction reaction is greatly promoted by twin defects engineered Pd cocatalyst. In this work, Pd nanoicosahedrons with twin defects were in-situ grown on C3N4 nanosheets, which effectively improve the photocatalytic performance in reduction of CO2 to CO and CH4 in comparison with Pd nanotetrahedrons without twin defects. It is proposed that the twin boundary (TB) terminations on the surface of Pd cocatalysts are highly catalytic active sites for CO2 reduction reaction. Based on the proposed mechanism, the photocatalytic activity and selectivity in CO2 reduction were further advanced through reducing the size of Pd icosahedral cocatalyst resulted from the increased surface density of TB terminations. The defect engineering on the surface of cocatalyst represents a novel route in realizing high-performance photocatalytic applications. © 2017 IOP Publishing Ltd.

  11. Enhancing the methanol tolerance of platinum nanoparticles for the cathode reaction of direct methanol fuel cells through a geometric design

    NASA Astrophysics Data System (ADS)

    Feng, Yan; Ye, Feng; Liu, Hui; Yang, Jun

    2015-11-01

    Mastery over the structure of nanoparticles might be an effective way to enhance their performance for a given application. Herein we demonstrate the design of cage-bell nanostructures to enhance the methanol tolerance of platinum (Pt) nanoparticles while remaining their catalytic activity for oxygen reduction reaction. This strategy starts with the synthesis of core-shell-shell nanoparticles with Pt and silver (Ag) residing respectively in the core and inner shell regions, which are then agitated with saturated sodium chloride (NaCl) solution to eliminate the Ag component from the inner shell region, leading to the formation of bimetallic nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a metal shell with nano-channels, which exhibit superior methanol-tolerant property in catalyzing oxygen reduction reaction due to the different diffusion behaviour of methanol and oxygen in the porous metal shell of cage-bell structured nanoparticles. In particular, the use of remarkably inexpensive chemical agent (NaCl) to promote the formation of cage-bell structured particles containing a wide spectrum of metal shells highlights its engineering merit to produce highly selective electrocatalysts on a large scale for the cathode reaction of direct methanol fuel cells.

  12. Mucosal Wave Measurement and Visualization Techniques

    PubMed Central

    Krausert, Christopher R.; Olszewski, Aleksandra E.; Taylor, Lindsay N.; McMurray, James S.; Dailey, Seth H.; Jiang, Jack J.

    2010-01-01

    Organized vibration of the vocal folds is critical to high quality voice production. When the vocal folds oscillate, the superficial tissue of the vocal fold is displaced in a wave-like fashion, creating the so called “mucosal wave”. Because the mucosal wave is dependent on vocal fold structure, physical alterations of that structure cause mucosal wave abnormalities. Visualization and quantification of mucosal wave properties have become useful parameters in diagnosing and managing vocal fold pathology. Mucosal wave measurement provides information about vocal fold characteristics that cannot be determined with other assessment techniques. Here, we discuss the benefits, disadvantages, and clinical applicability of the different mucosal wave measurement techniques, such as electroglottography (EGG), photoglottography (PGG), and ultrasound and visualization techniques that include videokymography (VKG), stroboscopy, and high-speed digital imaging (HSDI). The various techniques and their specific uses are reviewed with the intention of helping researchers and clinicians choose a method for a given situation and understand its limitations as well as its potential applications. Recent applications of these techniques for quantitative assessment demonstrate that additional research must be conducted to realize the full potential of these tools. Evaluations of existing research and recommendations for future research are given to promote both the quantitative study of the mucosal wave through accurate and standardized measurement of mucosal wave parameters and the development of reliable methods with which physicians can diagnose vocal disorders. PMID:20471798

  13. Mucosal Immunosenescence In The Gastrointestinal Tract

    PubMed Central

    Sato, Shintaro; Kiyono, Hiroshi; Fujihashi, Kohtaro

    2014-01-01

    It has been shown that pathogen-specific secretory IgA (SIgA) antibody (Ab) is the major player at mucosal surfaces for host defense. However, alterations in the mucosal immune system occur in advanced aging which results in a failure of induction of SIgA Abs for protection from infectious diseases. Signs of mucosal senescence first appear in the gut immune system. Further, changes in the intestinal microbiota most likely influence mucosal immunity. To overcome the immunological aging decline in mucosal immunity, several adjuvant systems including mucosal dendritic cell (DC) targeting have been shown to be attractive and effective immunological strategies. Similarly, antigen (Ag) uptake-M cells are ideal targets for facilitating Ag-specific mucosal immune responses. However, the numbers of M cells are reduced in aged mice. In this regard, Spi-B, an essential transcription factor for the functional and structural differentiation of M cells could be a potent strategy for the induction of effective mucosal immunity in aging. PMID:25531743

  14. Localized Pemphigus Vegetans without Mucosal Involvement.

    PubMed

    Jain, Vk; Jindal, N; Imchen, S

    2014-03-01

    Pemphigus vegetans is a rare variant of pemphigus vulgaris. A 62-year-old woman presented with erythematous moist vegetative plaque on the left breast and left groin. There was no mucosal involvement. Histopathological and direct immunofluorescence findings were suggestive of pemphigus vegetans. She showed excellent response to oral steroids. Literature is scarcely available on the limited involvement with pemphigus vegetans without mucosal involvement.

  15. Biology and Mucosal Immunity to Myxozoans

    PubMed Central

    Gómez, Daniela; Bartholomew, Jerri; Sunyer, J. Oriol

    2014-01-01

    Myxozoans are among the most abundant parasites in nature. Their life cycles involve two hosts: an invertebrate, usually an annelid, and a vertebrate, usually a fish. They affect fish species in their natural habitats but also constitute a menace for fish aquaculture. Using different strategies they are able to parasitize and cause damage in multiple organs, including mucosal tissues, which they use also as portals of entry. In fish, the main mucosal sites include the intestine, skin and gills. Recently the finding of a specific mucosal immunoglobulin in teleost (IgT), analogous to mammalian IgA, and the capacity of fish to develop a specific mucosal immune response against different pathogens, has highlighted the importance of studying immune responses at mucosal sites. In this review, we describe the major biological characteristics of myxozoan parasites and present the data available regarding immune responses for species that infect mucosal sites. As models for mucosal immunity we review the responses to Enteromyxum spp. and Ceratomyxa shasta, both of which parasitize the intestine. The immune response at the skin and gills is also described, as these mucosal tissues are used by myxozoans as attaching surfaces and portal of entry, and some species also parasitize these sites. Finally, the development of immunoprophylactic strategies is discussed. PMID:23994774

  16. Vaccination strategies for mucosal immune responses.

    PubMed

    Ogra, P L; Faden, H; Welliver, R C

    2001-04-01

    Mucosal administration of vaccines is an important approach to the induction of appropriate immune responses to microbial and other environmental antigens in systemic sites and peripheral blood as well as in most external mucosal surfaces. The development of specific antibody- or T-cell-mediated immunologic responses and the induction of mucosally induced systemic immunologic hyporesponsiveness (oral or mucosal tolerance) depend on complex sets of immunologic events, including the nature of the antigenic stimulation of specialized lymphoid structures in the host, antigen-induced activation of different populations of regulatory T cells (Th1 versus Th2), and the expression of proinflammatory and immunoregulatory cytokines. Availability of mucosal vaccines will provide a painless approach to deliver large numbers of vaccine antigens for human immunization. Currently, an average infant will receive 20 to 25 percutaneous injections for vaccination against different childhood infections by 18 months of age. It should be possible to develop for human use effective, nonliving, recombinant, replicating, transgenic, and microbial vector- or plant-based mucosal vaccines to prevent infections. Based on the experience with many dietary antigens, it is also possible to manipulate the mucosal immune system to induce systemic tolerance against environmental, dietary, and possibly other autoantigens associated with allergic and autoimmune disorders. Mucosal immunity offers new strategies to induce protective immune responses against a variety of infectious agents. Such immunization may also provide new prophylactic or therapeutic avenues in the control of autoimmune diseases in humans.

  17. Vaccination Strategies for Mucosal Immune Responses

    PubMed Central

    Ogra, Pearay L.; Faden, Howard; Welliver, Robert C.

    2001-01-01

    Mucosal administration of vaccines is an important approach to the induction of appropriate immune responses to microbial and other environmental antigens in systemic sites and peripheral blood as well as in most external mucosal surfaces. The development of specific antibody- or T-cell-mediated immunologic responses and the induction of mucosally induced systemic immunologic hyporesponsiveness (oral or mucosal tolerance) depend on complex sets of immunologic events, including the nature of the antigenic stimulation of specialized lymphoid structures in the host, antigen-induced activation of different populations of regulatory T cells (Th1 versus Th2), and the expression of proinflammatory and immunoregulatory cytokines. Availability of mucosal vaccines will provide a painless approach to deliver large numbers of vaccine antigens for human immunization. Currently, an average infant will receive 20 to 25 percutaneous injections for vaccination against different childhood infections by 18 months of age. It should be possible to develop for human use effective, nonliving, recombinant, replicating, transgenic, and microbial vector- or plant-based mucosal vaccines to prevent infections. Based on the experience with many dietary antigens, it is also possible to manipulate the mucosal immune system to induce systemic tolerance against environmental, dietary, and possibly other autoantigens associated with allergic and autoimmune disorders. Mucosal immunity offers new strategies to induce protective immune responses against a variety of infectious agents. Such immunization may also provide new prophylactic or therapeutic avenues in the control of autoimmune diseases in humans. PMID:11292646

  18. Prophylactic and therapeutic modulation of innate and adaptive immunity against mucosal infection of herpes simplex virus.

    PubMed

    Uyangaa, Erdenebileg; Patil, Ajit Mahadev; Eo, Seong Kug

    2014-08-01

    Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, CD4(+) Th1 T cells producing IFN-γ are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.

  19. Low-energy enhancement of nuclear γ strength and its impact on astrophysical reaction rates

    NASA Astrophysics Data System (ADS)

    Larsen, A. C.; Blasi, N.; Bracco, A.; Bürger, A.; Camera, F.; Eriksen, T. K.; Giacoppo, F.; Goriely, S.; Guttormsen, M.; Görgen, A.; Hagen, T. W.; Harissopulos, S.; Koehler, P. E.; Leoni, S.; Million, B.; Nyhus, H. T.; Renstrøm, T. T.; Rose, S.; Ruud, I. E.; Schiller, A.; Siem, S.; Tornyi, T.; Tveten, G. M.; Voinov, A. V.; Wiedeking, M.

    2014-03-01

    An unexpected enhancement in the low-energy part of the γ-strength function for light and medium-mass nuclei has been discovered at the Oslo Cyclotron Laboratory. This enhancement could lead to an increase in the neutron-capture rates up to two orders of magnitude for very exotic, neutron-rich nuclei. However, it is still an open question whether this structure persists when approaching the neutron drip line.

  20. Plasma-enhanced microwave solid-state synthesis of cadmium sulfide: reaction mechanism and optical properties.

    PubMed

    Du, Ke-zhao; Chaturvedi, Apoorva; Wang, Xing-zhi; Zhao, Yi; Zhang, Ke-ke; Iqbal Bakti Utama, M; Hu, Peng; Jiang, Hui; Xiong, Qi-hua; Kloc, Christian

    2015-08-14

    CdS synthesis by plasma-enhanced microwave physical vapor transport (PMPVT) has been developed in this work. The photoluminescence (PL), absorbance, Raman spectra and the mechanism of CdS crystal growth have been investigated. Furthermore, plasma-enhanced microwave chemical vapour transport (PMCVT) synthesis of CdS with additional chemical transport agents has been explored. In addition, other II-VI chalcogenides were also synthesized by PMPVT.

  1. Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

    DOEpatents

    Tonkovich, Anna Lee Y.; Wang, Yong; Wegeng, Robert S.; Gao, Yufei

    2003-09-09

    Reactors and processes are disclosed that can utilize high heat fluxes to obtain fast, steady-state reaction rates. Porous catalysts used in conjunction with microchannel reactors to obtain high rates of heat transfer are also disclosed. Reactors and processes that utilize short contact times, high heat flux and low pressure drop are described. Improved methods of steam reforming are also provided.

  2. Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

    DOEpatents

    Tonkovich, Anna Lee Y.; Wang, Yong; Wegeng, Robert S.; Gao, Yufei

    2006-05-16

    Reactors and processes are disclosed that can utilize high heat fluxes to obtain fast, steady-state reaction rates. Porous catalysts used in conjunction with microchannel reactors to obtain high rates of heat transfer are also disclosed. Reactors and processes that utilize short contact times, high heat flux and low pressure drop are described. Improved methods of steam reforming are also provided.

  3. Microwave-enhanced cross-coupling reactions involving alkynyltrifluoroborates with aryl bromides.

    PubMed

    Coltuclu, Vitali; Dadush, Eric; Naravane, Abhijit; Kabalka, George W

    2013-01-29

    Palladium-catalyzed alkynylation has emerged as one of the most reliable methods for the synthesis of alkynes which are often used in natural product syntheses and material science. An efficient method for coupling alkynyltrifluoroborates with various aryl bromides in the presence of a palladium catalyst has been developed using microwave irradiation. The microwave reactions are rapid and efficient.

  4. ENHANCING THE STABILITY OF POROUS CATALYSTS WITH SUPERCRITICAL REACTION MEDIA. (R826034)

    EPA Science Inventory

    Adsorption/desorption and pore-transport are key parameters influencing the activity and product selectivity in porous catalysts. With conventional reaction media (gas or liquid phase), one of these parameters is generally favorable while the other is not. For instance, while ...

  5. ENHANCING THE STABILITY OF POROUS CATALYSTS WITH SUPERCRITICAL REACTION MEDIA. (R826034)

    EPA Science Inventory

    Adsorption/desorption and pore-transport are key parameters influencing the activity and product selectivity in porous catalysts. With conventional reaction media (gas or liquid phase), one of these parameters is generally favorable while the other is not. For instance, while ...

  6. Emphasizing Multiple Levels of Representation to Enhance Students' Understandings of the Changes Occurring during Chemical Reactions

    ERIC Educational Resources Information Center

    Chandrasegaran, A. L.; Treagust, David F.; Mocerino, Mauro

    2009-01-01

    An alternative program of instruction was implemented with 33 high-achieving Grade 9 students (15-16 years old) in Singapore that overtly focused on the use of macroscopic, submicroscopic, and symbolic representations to describe and explain the changes that occurred during the burning of metals, reactions of dilute acids, ionic precipitations,…

  7. Emphasizing Multiple Levels of Representation to Enhance Students' Understandings of the Changes Occurring during Chemical Reactions

    ERIC Educational Resources Information Center

    Chandrasegaran, A. L.; Treagust, David F.; Mocerino, Mauro

    2009-01-01

    An alternative program of instruction was implemented with 33 high-achieving Grade 9 students (15-16 years old) in Singapore that overtly focused on the use of macroscopic, submicroscopic, and symbolic representations to describe and explain the changes that occurred during the burning of metals, reactions of dilute acids, ionic precipitations,…

  8. Mucosal vaccines: a paradigm shift in the development of mucosal adjuvants and delivery vehicles.

    PubMed

    Srivastava, Atul; Gowda, Devegowda Vishakante; Madhunapantula, SubbaRao V; Shinde, Chetan G; Iyer, Meenakshi

    2015-04-01

    Mucosal immune responses are the first-line defensive mechanisms against a variety of infections. Therefore, immunizations of mucosal surfaces from which majority of infectious agents make their entry, helps to protect the body against infections. Hence, vaccinization of mucosal surfaces by using mucosal vaccines provides the basis for generating protective immunity both in the mucosal and systemic immune compartments. Mucosal vaccines offer several advantages over parenteral immunization. For example, (i) ease of administration; (ii) non-invasiveness; (iii) high-patient compliance; and (iv) suitability for mass vaccination. Despite these benefits, to date, only very few mucosal vaccines have been developed using whole microorganisms and approved for use in humans. This is due to various challenges associated with the development of an effective mucosal vaccine that can work against a variety of infections, and various problems concerned with the safe delivery of developed vaccine. For instance, protein antigen alone is not just sufficient enough for the optimal delivery of antigen(s) mucosally. Hence, efforts have been made to develop better prophylactic and therapeutic vaccines for improved mucosal Th1 and Th2 immune responses using an efficient and safe immunostimulatory molecule and novel delivery carriers. Therefore, in this review, we have made an attempt to cover the recent advancements in the development of adjuvants and delivery carriers for safe and effective mucosal vaccine production.

  9. Enhanced Reactivity in Nucleophilic Acyl Substitution Ion/Ion Reactions Using Triazole-Ester Reagents

    NASA Astrophysics Data System (ADS)

    Bu, Jiexun; Peng, Zhou; Zhao, Feifei; McLuckey, Scott A.

    2017-02-01

    The acyl substitution reactions between 1-hydroxy-7-aza-benzotriazole (HOAt)/1-hydroxy-benzotriazole (HOBt) ester reagents and nucleophilic side chains on peptides have been demonstrated in the gas phase via ion/ion reactions. The HOAt/HOBt ester reagents were synthesized in solution and ionized via negative nano-electrospray ionization. The anionic reagents were then reacted with doubly protonated model peptides containing amines, guanidines, and imidazoles in the gas phase. The complexes formed in the reaction cell were further probed with ion trap collision induced dissociation (CID) yielding either a covalently modified analyte ion or a proton transfer product ion. The covalent reaction yield of HOAt/HOBt ester reagents was demonstrated to be higher than the yield with N-hydroxysuccinimide (NHS) ester reagents over a range of equivalent conditions. Density functional theory (DFT) calculations were performed with a primary amine model system for both triazole-ester and NHS-ester reactants, which indicated a lower transition state barrier for the former reagent, consistent with experiments. The work herein demonstrates that the triazole-ester reagents are more reactive, and therefore less selective, than the analogous NHS-ester reagent. As a consequence, the triazole-ester reagents are the first to show efficient reactivity with unprotonated histidine residues in the gas phase. For all nucleophilic sites and all reagents, covalent reactions are favored under long time, low amplitude activation conditions. This work presents a novel class of reagents capable of gas-phase conjugation to nucleophilic sites in analyte ions via ion/ion chemistry.

  10. Baicalin inhibits the fenton reaction by enhancing electron transfer from Fe (2+) to dissolved oxygen.

    PubMed

    Nishizaki, Daisuke; Iwahashi, Hideo

    2015-01-01

    Sho-saiko-to is an herbal medicine that is known to have diverse pharmacological activities and has been used for the treatment of various infectious diseases. Here, we examined the effects of baicalin, a compound isolated from Sho-saiko-to, and the effects of the iron chelator quinolinic acid on the Fenton reaction. The control reaction mixture contained 0.1 M 5,5-dimethyl-1-pyrroline N-oxide (DMPO), 0.2 mM H 2 O 2, 0.2 mM FeSO 4( NH 4)2 SO 4, and 40 mM sodium phosphate buffer (pH 7.4). Upon the addition of 0.6 mM baicalin or quinolinic acid to the control reaction mixture, the ESR peak heights of DMPO/OH radical adducts were measured as 32% ± 1% (baicalin) and 166% ± 27% (quinolinic acid) of that of the control mixture. In order to clarify why baicalin and quinolinic acid exerted opposite effects on the formation of hydroxyl radicals, we measured oxygen consumption in the presence of either compound. Upon the addition of 0.6 mM baicalin (or quinolinic acid) to the control reaction mixture without DMPO and H 2 O 2, the relative oxygen consumption rates were found to be 449% ± 40% (baicalin) and 18% ± 9% (quinolinic acid) of that of the control mixture without DMPO and H 2 O 2, indicating that baicalin facilitated the transfer of electrons from Fe (2+) to dissolved oxygen. Thus, the great majority of Fe (2+) turned into Fe (3+), and the formation of hydroxyl radicals was subsequently inhibited in this reaction.

  11. Enhanced Reactivity in Nucleophilic Acyl Substitution Ion/Ion Reactions Using Triazole-Ester Reagents

    NASA Astrophysics Data System (ADS)

    Bu, Jiexun; Peng, Zhou; Zhao, Feifei; McLuckey, Scott A.

    2017-07-01

    The acyl substitution reactions between 1-hydroxy-7-aza-benzotriazole (HOAt)/1-hydroxy-benzotriazole (HOBt) ester reagents and nucleophilic side chains on peptides have been demonstrated in the gas phase via ion/ion reactions. The HOAt/HOBt ester reagents were synthesized in solution and ionized via negative nano-electrospray ionization. The anionic reagents were then reacted with doubly protonated model peptides containing amines, guanidines, and imidazoles in the gas phase. The complexes formed in the reaction cell were further probed with ion trap collision induced dissociation (CID) yielding either a covalently modified analyte ion or a proton transfer product ion. The covalent reaction yield of HOAt/HOBt ester reagents was demonstrated to be higher than the yield with N-hydroxysuccinimide (NHS) ester reagents over a range of equivalent conditions. Density functional theory (DFT) calculations were performed with a primary amine model system for both triazole-ester and NHS-ester reactants, which indicated a lower transition state barrier for the former reagent, consistent with experiments. The work herein demonstrates that the triazole-ester reagents are more reactive, and therefore less selective, than the analogous NHS-ester reagent. As a consequence, the triazole-ester reagents are the first to show efficient reactivity with unprotonated histidine residues in the gas phase. For all nucleophilic sites and all reagents, covalent reactions are favored under long time, low amplitude activation conditions. This work presents a novel class of reagents capable of gas-phase conjugation to nucleophilic sites in analyte ions via ion/ion chemistry.

  12. Mucosal vaccines: novel strategies and applications for the control of pathogens and tumors at mucosal sites.

    PubMed

    Nizard, Mevyn; Diniz, Mariana O; Roussel, Helene; Tran, Thi; Ferreira, Luis Cs; Badoual, Cecile; Tartour, Eric

    2014-01-01

    The mucosal immune system displays several adaptations reflecting the exposure to the external environment. The efficient induction of mucosal immune responses also requires specific approaches, such as the use of appropriate administration routes and specific adjuvants and/or delivery systems. In contrast to vaccines delivered via parenteral routes, experimental, and clinical evidences demonstrated that mucosal vaccines can efficiently induce local immune responses to pathogens or tumors located at mucosal sites as well as systemic response. At least in part, such features can be explained by the compartmentalization of mucosal B and T cell populations that play important roles in the modulation of local immune responses. In the present review, we discuss molecular and cellular features of the mucosal immune system as well as novel immunization approaches that may lead to the development of innovative and efficient vaccines targeting pathogens and tumors at different mucosal sites.

  13. Enhancement of nucleate pool boiling heat transfer to dilute binary mixtures using endothermic chemical reactions around the smoothed horizontal cylinder

    NASA Astrophysics Data System (ADS)

    Sarafraz, M. M.; Peyghambarzadeh, S. M.; Alavifazel, S. A.

    2012-10-01

    Experimental studies on enhancing the pool boiling heat transfer coefficient of binary dilute mixtures of water/glycerol, water/MEG (Mono-ethylene glycol) and water/DEG (di-ethylene glycol) have been carried out. Some particular endothermic chemical reactions related to ammonium salts were used to enhance the pool boiling heat transfer coefficient, simultaneously with occurrence of pool boiling heat transfer. Accordingly, 100 g of Ammonium nitrate, ammonium perborate and Ammonium sulfate were selected to dissolve into mixtures. High and extreme solution enthalpies of each of these ammonium salt powders are employed to reduce the surface temperature around the horizontal cylinder locally. Results demonstrated that presence of ammonium salts into the mixtures deteriorates the surface temperature of cylinder and as the result, higher pool boiling heat transfer coefficient is reported for tested solutions. Results are also reported and compared for different ammonium salts to find the influence of inducing different enthalpies of solution on pool boiling heat transfer coefficient. Obtained results also indicated that presence of endothermic reaction besides the pool boiling heat transfer enhances the heat transfer coefficients in comparison with nucleate pool boiling phenomenon solely.

  14. Enhanced Colloidal Stability of CeO2 Nanoparticles by Ferrous Ions: Adsorption, Redox Reaction, and Surface Precipitation.

    PubMed

    Liu, Xuyang; Ray, Jessica R; Neil, Chelsea W; Li, Qingyun; Jun, Young-Shin

    2015-05-05

    Due to the toxicity of cerium oxide (CeO2) nanoparticles (NPs), a better understanding of the redox reaction-induced surface property changes of CeO2 NPs and their transport in natural and engineered aqueous systems is needed. This study investigates the impact of redox reactions with ferrous ions (Fe2+) on the colloidal stability of CeO2 NPs. We demonstrated that under anaerobic conditions, suspended CeO2 NPs in a 3 mM FeCl2 solution at pH 4.8 were much more stable against sedimentation than those in the absence of Fe2+. Redox reactions between CeO2 NPs and Fe2+ lead to the formation of 6-line ferrihydrite on the CeO2 surfaces, which enhanced the colloidal stability by increasing the zeta potential and hydrophilicity of CeO2 NPs. These redox reactions can affect the toxicity of CeO2 NPs by increasing cerium dissolution, and by creating new Fe(III) (hydr)oxide reactive surface layers. Thus, these findings have significant implications for elucidating the phase transformation and transport of redox reactive NPs in the environment.

  15. Enhanced Reaction Kinetics and Structure Integrity of Ni/SnO2 Nanocluster toward High-Performance Lithium Storage.

    PubMed

    Jiang, Yinzhu; Li, Yong; Zhou, Peng; Yu, Shenglan; Sun, Wenping; Dou, Shixue

    2015-12-09

    SnO2 is regarded as one of the most promising anodes via conversion-alloying mechanism for advanced lithium ion batteries. However, the sluggish conversion reaction severely degrades the reversible capacity, Coulombic efficiency and rate capability. In this paper, through constructing porous Ni/SnO2 composite electrode composed of homogeneously distributed SnO2 and Ni nanoparticles, the reaction kinetics of SnO2 is greatly enhanced, leading to full conversion reaction, superior cycling stability and improved rate capability. The uniformly distributed Ni nanoparticles provide a fast charge transport pathway for electrochemical reactions, and restrict the direct contact and aggregation of SnO2 nanoparticles during cycling. In the meantime, the void space among the nanoclusters increases the contact area between the electrolyte and active materials, and accommodates the huge volume change during cycling as well. The Ni/SnO2 composite electrode possesses a high reversible capacity of 820.5 mAh g(-1) at 1 A g(-1) up to 100 cycles. More impressively, large capacity of 841.9, 806.6, and 770.7 mAh g(-1) can still be maintained at high current densities of 2, 5, and 10 A g(-1) respectively. The results demonstrate that Ni/SnO2 is a high-performance anode for advanced lithium-ion batteries with high specific capacity, excellent rate capability, and cycling stability.

  16. Flagellin modulates functions of the follicle-associated epithelium to facilitate uptake of particles into organized mucosal lymphoid tissues

    PubMed Central

    Chabot, Sophie M.; Shawi, May; Eaves-Pyles, Tonyia; Neutra, Marian R.

    2016-01-01

    Bacterial flagellin activates innate immune responses by signaling through TLR5, and is a potential vaccine adjuvant. Mucosal lymphoid follicles, inductive sites for adaptive mucosal immune responses, are covered by a follicle-associated epithelium (FAE) specialized for uptake of antigens. This study demonstrates that mucosal application of S.dublin flagellin enhanced transepithelial transport of microparticles by the FAE of mouse Peyer's patch in vivo. Flagellin also induced rapid, matrix metalloproteinase-dependent migration of subepithelial dendritic cells (DCs) into the FAE, better positioning DCs for antigen capture. These innate responses to flagellin enhance FAE functions and may promote adaptive immune responses in the mucosa. PMID:18721059

  17. Alteration of the Redox State with Reactive Oxygen Species for 5-Fluorouracil-Induced Oral Mucositis in Hamsters

    PubMed Central

    Wada-Takahashi, Satoko; Takahashi, Shun-suke; Lee, Masaichi Chang-il

    2013-01-01

    Oral mucositis is often induced in patients receiving cancer chemotherapy treatment. It has been reported that oral mucositis can reduce quality of life, as well as increasing the incidence of mortality. The participation of reactive oxygen species (ROS) in the pathogenesis of oral mucositis is well known, but no report has actually demonstrated the presence of ROS. Thus, the purpose of this study was thus to demonstrate the involvement of ROS and the alteration of the redox state in oral mucositis using an in vivo L-band electron spin resonance (ESR) technique. An oral mucositis animal model induced by treatment of 5-fluorouracil with 10% acetic acid in hamster cheek pouch was used. Lipid peroxidation was measured as the level of malondialdehyde determined by the thiobarbituric acid reaction. The rate constants of the signal decay of nitroxyl compounds using in vivo L-band ESR were calculated from the signal decay curves. Firstly, we established the oral mucositis animal model induced by treatment of 5-fluorouracil with acetic acid in hamster cheek pouch. An increased level of lipid peroxidation in oral mucositis was found by measuring malondialdehyde using isolated hamster cheek pouch ulcer. In addition, as a result of in vivo L-band ESR measurements using our model animals, the decay rate constants of carbamoyl-PROXYL, which is a reagent for detecting the redox balance in tissue, were decreased. These results suggest that a redox imbalance might occur by excessive generation of ROS at an early stage of oral mucositis and the consumption of large quantities of antioxidants including glutathione in the locality of oral mucositis. These findings support the presence of ROS involved in the pathogenesis of oral mucositis with anti-cancer therapy, and is useful for the development of novel therapies drugs for oral mucositis. PMID:24376587

  18. Mucositis management in patients with cancer.

    PubMed

    Keefe, Dorothy M K

    2006-04-01

    Mucositis is an important toxicity to be aware of in anticancer therapy. It contributes to a reduction in cure rates from cancer. Until recently, it has been poorly understood and therefore has not been well managed. It causes patient distress, delays in treatment administration, and reductions in dose intensity, and it costs the health-care system a large amount of money. Mucositis has traditionally been associated more with hematologic malignancies than with solid tumors, because the incidence of severe mucositis has been much higher with the high-dose chemotherapy regimens used in hematologic malignancies. However, the chemotherapy used in solid tumors also causes mucositis and deserves further study. The separation between oral and gastrointestinal mucositis is potentially false and is being removed, with much research now investigating the entire alimentary canal. There are similarities and differences between radiation therapy- and chemotherapy-induced mucositis, and these have implications for treatment and prevention scheduling and type. Risk prediction is another area that requires more work, but there is real hope that, in the future, we might be able to predict who will suffer from mucositis and in which parts of the alimentary canal, thus enabling us to appropriately target the newer antimucotoxic therapies. The Mucositis Study Goup of the Multinational Association for Supportive Care in Cancer has recently published management guidelines for oral and gastrointestinal mucositis and is in the process of updating them. The guidelines serve as an excellent starting place for future mucositis research because they not only review the available treatments but also discuss mechanisms and epidemiology.

  19. A nickel nanocatalyst within a h-BN shell for enhanced hydrogen oxidation reactions.

    PubMed

    Gao, Lijun; Wang, Ying; Li, Haobo; Li, Qihao; Ta, Na; Zhuang, Lin; Fu, Qiang; Bao, Xinhe

    2017-08-01

    The development of low-cost and high-performance electrocatalysts remains a challenge for the hydrogen oxidation reaction (HOR) in alkaline membrane fuel cells. Here, we have reported novel Ni@h-BN core-shell nanocatalysts consisting of nickel nanoparticles encapsulated in few-layer h-BN shells. The Ni@h-BN catalysts exhibit an improved HOR performance compared with the bare Ni nanoparticles. In situ characterization experiments and density functional theory calculations indicate that the interactions of the O, H, and OH species with the Ni surface under the h-BN shell are weakened, which helps to maintain the active metallic Ni phase both in air and in the electrolyte and strengthen the HOR processes occurring at the h-BN/Ni interfaces. These results suggest a new route for designing high-performance non-noble metal electrocatalysts with encapsulating two-dimensional material overlayers for HOR reactions.

  20. Covalent grafting of carbon nanotubes with a biomimetic heme model compound to enhance oxygen reduction reactions.

    PubMed

    Wei, Ping-Jie; Yu, Guo-Qiang; Naruta, Yoshinori; Liu, Jin-Gang

    2014-06-23

    The oxygen reduction reaction (ORR) is one of the most important reactions in both life processes and energy conversion systems. The replacement of noble-metal Pt-based ORR electrocatalysts by nonprecious-metal catalysts is crucial for the large-scale commercialization of automotive fuel cells. Inspired by the mechanisms of dioxygen activation by metalloenzymes, herein we report a structurally well-defined, bio-inspired ORR catalyst that consists of a biomimetic model compound-an axial imidazole-coordinated porphyrin-covalently attached to multiwalled carbon nanotubes. Without pyrolysis, this bio-inspired electrocatalyst demonstrates superior ORR activity and stability compared to those of the state-of-the-art Pt/C catalyst in both acidic and alkaline solutions, thus making it a promising alternative as an ORR electrocatalyst for application in fuel-cell technology.

  1. Prediction of enhanced solvent-induced enantioselectivity for a ring opening with a bifurcating reaction path

    SciTech Connect

    Carpenter, Barry K.; Harvey, Jeremy N.; Glowacki, David R.

    2014-12-11

    Classical molecular dynamics simulations are reported for the deazetisation and ring opening of meso-2,3-difluoro-2,3-dimethyldiazocyclopropane in three solvents: CHCl3, CHFClBr and CH3CH(OH)CF3 (TFIPA). In this study, the achiral reactant leads to enantiomeric allene products, and the question addressed in the study is whether either of the chiral, enantiomerically pure solvents can induce significant enantiomeric excess in the products. The direct dynamics calculations use an empirical valence bond potential for the solute, with empirical parameters optimised against M06-2X/cc-pVTZ density functional results. The results reveal that the exothermic N2 loss and ring opening promote transient strong solvent–solute interactions within the first ~100 fs of the reaction. Because of the bifurcating reaction path, these interactions occur at time when the “decision” about which enantiomer of the product to form has yet to be made (at least for many of the trajectories). Hence, it is possible in principle that the solvent could exert a larger-than-normal influence on the course of the reaction. In fact, the results reveal no such effect for CHFClBr but do predict that TFIPA should induce 15.2 ± 2.1% enantiomeric excess. This is roughly an order of magnitude larger than solvent-induced enantiomeric excesses found experimentally in reactions where the conversion of reactant(s) to enantiomeric products occur over separate transition states.

  2. Prediction of enhanced solvent-induced enantioselectivity for a ring opening with a bifurcating reaction path

    DOE PAGES

    Carpenter, Barry K.; Harvey, Jeremy N.; Glowacki, David R.

    2014-12-11

    Classical molecular dynamics simulations are reported for the deazetisation and ring opening of meso-2,3-difluoro-2,3-dimethyldiazocyclopropane in three solvents: CHCl3, CHFClBr and CH3CH(OH)CF3 (TFIPA). In this study, the achiral reactant leads to enantiomeric allene products, and the question addressed in the study is whether either of the chiral, enantiomerically pure solvents can induce significant enantiomeric excess in the products. The direct dynamics calculations use an empirical valence bond potential for the solute, with empirical parameters optimised against M06-2X/cc-pVTZ density functional results. The results reveal that the exothermic N2 loss and ring opening promote transient strong solvent–solute interactions within the first ~100 fsmore » of the reaction. Because of the bifurcating reaction path, these interactions occur at time when the “decision” about which enantiomer of the product to form has yet to be made (at least for many of the trajectories). Hence, it is possible in principle that the solvent could exert a larger-than-normal influence on the course of the reaction. In fact, the results reveal no such effect for CHFClBr but do predict that TFIPA should induce 15.2 ± 2.1% enantiomeric excess. This is roughly an order of magnitude larger than solvent-induced enantiomeric excesses found experimentally in reactions where the conversion of reactant(s) to enantiomeric products occur over separate transition states.« less

  3. Idiopathic mucosal penile squamous papillomas in dogs.

    PubMed

    Cornegliani, Luisa; Vercelli, Antonella; Abramo, Francesca

    2007-12-01

    A new papillomatous clinical entity is described affecting the penile mucosa of dogs. The animals, 11 male dogs of different breeds, ageing from 6 to 13 years, were presented for genital mass and occasional haematuria. Surgical incision of the prepuce skin of the anaesthetized dogs showed the presence of single pedunculated, soft, pink-red, cauliflower-like masses arising from the penile mucosa, with diameter ranging from 2 to 8 cm. In all cases, histopathological examination of the excised masses showed normal epithelial differentiation with digitiform expansion of all the layers and elongated rete ridges slanted towards the periphery of the lesion. Evidence of ballooning degeneration or basophilic intranuclear inclusion bodies was not found. Both immunohistochemistry and polymerase chain reaction techniques failed to reveal papillomavirus. According to the histological World Health Organization classification of papillomatous lesions and due to the lack of evidence of a viral origin the masses were identified as idiopathic mucosal penile squamous papillomas. Urinary problems resolved after surgical excision, haematuria was therefore considered secondary to ulceration of the papillated masses.

  4. Human papillomavirus DNA in oral mucosal lesions.

    PubMed

    Giovannelli, Lucia; Campisi, Giuseppina; Lama, Anna; Giambalvo, Ornella; Osborn, John; Margiotta, Valerio; Ammatuna, Pietro

    2002-03-15

    This study determined the presence of human papillomavirus (HPV) DNA in oral mucosa cells from 121 patients with different types of oral mucosal lesions (13 squamous cell carcinomas, 59 potentially malignant lesions, 49 benign erosive ulcerative lesions) and from 90 control subjects. HPV DNA was detected by nested polymerase chain reaction, and genotype was determined by DNA sequencing. HPV prevalence was 61.5% in carcinomas, 27.1% in potentially malignant lesions, 26.5% in erosive ulcerative lesions, and 5.5% in control subjects. The risk of malignant or potentially malignant lesions was associated with HPV and was statistically significant. HPV-18 was found in 86.5% of HPV-positive lesions but was not associated with a particular type of lesion and was found in 80% of the HPV-positive control subjects. HPV infection was related to older age but not to sex, smoking, or alcohol use; the presence of lesions in the oral cavity increased the risk of HPV infection.

  5. Enhanced biomolecular detection based on localized surface plasmon resonance (LSPR) using enzyme-precipitation reaction.

    PubMed

    Lee, Seung-Woo; Ahn, Junhyoung; Kim, Min-Gon; Shin, Yong-Beom; Lee, Jae Jong; Lim, Ki-Pil; Kim, Ki-Bum

    2010-05-01

    An enzyme-catalyzed precipitation reaction was employed as a means to increase the change in the LSPR signal after intermolecular bindings between antigens and antibodies occurred on gold nanodot surfaces. The gold nanodot array with an diameter of 175 nm and a thickness of 20 nm was fabricated on a glass wafer using thermal nanoimprint lithography. The human interleukin (hIL) 5 antibody was immobilized on the gold nanodot, followed by binding of hIL 5 to the anti-hIL 5. Subsequently, a biotinylated anti-hIL 5 and a alkaline phosphatase conjugated with streptavidin were simultaneously introduced. A mixture of 5-bromo-4-chloro-3-indolyl phosphate p-toluidine (BCIP) and nitro blue tetrazolium (NBT) was then used for precipitation, which resulted from the biocatalytic reaction of the alkaline phosphatase on gold nanodot. The LSPR spectra were obtained after each binding process. Using this analysis, the enzyme-catalyzed precipitation reaction on gold nanodots was found to be effective in amplifying the change in the peak wavelength of LSPR after molecular bindings.

  6. Visible-light-enhanced catalytic oxidation reactions on plasmonic silver nanostructures.

    PubMed

    Christopher, Phillip; Xin, Hongliang; Linic, Suljo

    2011-06-01

    Catalysis plays a critical role in chemical conversion, energy production and pollution mitigation. High activation barriers associated with rate-limiting elementary steps require most commercial heterogeneous catalytic reactions to be run at relatively high temperatures, which compromises energy efficiency and the long-term stability of the catalyst. Here we show that plasmonic nanostructures of silver can concurrently use low-intensity visible light (on the order of solar intensity) and thermal energy to drive catalytic oxidation reactions--such as ethylene epoxidation, CO oxidation, and NH₃ oxidation--at lower temperatures than their conventional counterparts that use only thermal stimulus. Based on kinetic isotope experiments and density functional calculations, we postulate that excited plasmons on the silver surface act to populate O₂ antibonding orbitals and so form a transient negative-ion state, which thereby facilitates the rate-limiting O₂-dissociation reaction. The results could assist the design of catalytic processes that are more energy efficient and robust than current processes.

  7. Reaction/separation process for enhanced methane conversion. Final report, January 1990-December 1994

    SciTech Connect

    Gokhale, Y.V.; Falconer, J.L.; Noble, R.D.

    1995-06-01

    The conventional process for methanol production from natural gas (CH4) is a two-step, energy intensive process. In constrat, direct partial oxidation is a single-step, energy efficient process, but methanol yield is limited due to its thermal instability. The authors proposed a membrane reactor system that could potentially increase the methanol yield. A non-isothermal membrane reactor with a tubular membrane, and a cooling tube located coaxially inside the membrane was built. A pre-heating and a post-membrane sections maintained a constant reactor-wall-temperature in the membrane section. The membrane did not selectively remove methanol from the reaction zone, but it effectively distributed the reaction mixture over the cooling tube which quenched the reaction mixture, and thereby increased the methanol yield. The maximum methanol yield of 3.3% was obtained at 3.5 MPa with 8% O2 in CH4 as feed; the reactor wall temperature was 800 K. Zeolite membranes of silicalite-1 were prepared, and used in a pervaporation apparatus. The membrane increased the methanol concentration from 46 vol% in the feed (as obtained in our membrane reactor study) to 92 vol% in the permeate. Temperature profiles in the reactor were computed by solving momentum and thermal energy balances. The profiles indicated that the postmembrane section could be detrimental to products that are unstable above 420 K.

  8. Adjusting the Chemical Bonding of SnO2 @CNT Composite for Enhanced Conversion Reaction Kinetics.

    PubMed

    Cheng, Yayi; Huang, Jianfeng; Qi, Hui; Cao, Liyun; Yang, Jun; Xi, Qiao; Luo, Xiaomin; Yanagisawa, Kazumichi; Li, Jiayin

    2017-08-01

    Carbon nanotubes (CNTs) with excellent electron conductivity are widely used to improve the electrochemical performance of the SnO2 anode. However, the chemical bonding between SnO2 and CNTs is not clearly elucidated despite it may affect the lithiation/delithiation behavior greatly. In this work, an SnO2 @CNT composite with SnC and SnOC bonds as a linkage bridge is reported and the influence of the SnC and SnOC bonds on the lithium storage properties is revealed. It is found that the SnC bond can act as an ultrafast electron transfer path, facilitating the reversible conversion reaction between Sn and Li2 O to form SnO2 . Therefore, the SnO2 @CNT composite with more SnC bond shows high reversible capacity and nearly half capacity contributes from conversion reaction. It is opposite for the SnO2 @CNT composite with more SnOC bond that the electrons cannot be transferred directly to CNTs, resulting in depressed conversion reaction kinetics. Consequently, this work can provide new insight for exploration and design of metal oxide/carbon composite anode materials in lithium-ion battery. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Intestinal mucosal atrophy and adaptation.

    PubMed

    Shaw, Darcy; Gohil, Kartik; Basson, Marc D

    2012-11-28

    Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes.

  10. Radiation-Induced Oral Mucositis

    PubMed Central

    Maria, Osama Muhammad; Eliopoulos, Nicoletta; Muanza, Thierry

    2017-01-01

    Radiation-induced oral mucositis (RIOM) is a major dose-limiting toxicity in head and neck cancer patients. It is a normal tissue injury caused by radiation/radiotherapy (RT), which has marked adverse effects on patient quality of life and cancer therapy continuity. It is a challenge for radiation oncologists since it leads to cancer therapy interruption, poor local tumor control, and changes in dose fractionation. RIOM occurs in 100% of altered fractionation radiotherapy head and neck cancer patients. In the United Sates, its economic cost was estimated to reach 17,000.00 USD per patient with head and neck cancers. This review will discuss RIOM definition, epidemiology, impact and side effects, pathogenesis, scoring scales, diagnosis, differential diagnosis, prevention, and treatment. PMID:28589080

  11. Radiation-Induced Oral Mucositis.

    PubMed

    Maria, Osama Muhammad; Eliopoulos, Nicoletta; Muanza, Thierry

    2017-01-01

    Radiation-induced oral mucositis (RIOM) is a major dose-limiting toxicity in head and neck cancer patients. It is a normal tissue injury caused by radiation/radiotherapy (RT), which has marked adverse effects on patient quality of life and cancer therapy continuity. It is a challenge for radiation oncologists since it leads to cancer therapy interruption, poor local tumor control, and changes in dose fractionation. RIOM occurs in 100% of altered fractionation radiotherapy head and neck cancer patients. In the United Sates, its economic cost was estimated to reach 17,000.00 USD per patient with head and neck cancers. This review will discuss RIOM definition, epidemiology, impact and side effects, pathogenesis, scoring scales, diagnosis, differential diagnosis, prevention, and treatment.

  12. Intestinal mucosal atrophy and adaptation

    PubMed Central

    Shaw, Darcy; Gohil, Kartik; Basson, Marc D

    2012-01-01

    Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes. PMID:23197881

  13. Utilization of Fc receptors as a mucosal vaccine strategy against an intracellular bacterium, Francisella tularensis.

    PubMed

    Rawool, Deepak B; Bitsaktsis, Constantine; Li, Ying; Gosselin, Diane R; Lin, Yili; Kurkure, Nitin V; Metzger, Dennis W; Gosselin, Edmund J

    2008-04-15

    Numerous studies have demonstrated that targeting Ag to Fc receptors (FcR) on APCs can enhance humoral and cellular immunity. However, studies are lacking that examine both the use of FcR-targeting in generating immune protection against infectious agents and the use of FcRs in the induction of mucosal immunity. Francisella tularensis is a category A intracellular mucosal pathogen. Thus, intense efforts are underway to develop a vaccine against this organism. We hypothesized that protection against mucosal infection with F. tularensis would be significantly enhanced by targeting inactivated F. tularensis live vaccine strain (iFt) to FcRs at mucosal sites, via intranasal immunization with mAb-iFt complexes. These studies demonstrate for the first time that: 1) FcR-targeted immunogen enhances immunogen-specific IgA production and protection against subsequent infection in an IgA-dependent manner, 2) FcgammaR and neonatal FcR are crucial to this protection, and 3) inactivated F. tularensis, when targeted to FcRs, enhances protection against the highly virulent SchuS4 strain of F. tularensis, a category A biothreat agent. In summary, these studies show for the first time the use of FcRs as a highly effective vaccination strategy against a highly virulent mucosal intracellular pathogen.

  14. Mechanical bending induced catalytic activity enhancement of monolayer 1 T'-MoS2 for hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Shi, Wenwu; Wang, Zhiguo; Fu, Yong Qing

    2017-09-01

    In this paper, mechanisms behind enhancement of catalytic activity of MoS2 mono-layer (three atomic layers) for hydrogen evolution reaction (HER) by mechanically applying bending strain were investigated using density functional theory. Results showed that with the increase of bending strains, the Gibbs free energy for hydrogen adsorption on the MoS2 mono-layer was decreased from 0.18 to -0.04 eV and to 0.13 eV for the bend strains applied along the zigzag and armchair directions, respectively. The mechanism for the enhanced catalytic activity comes from the changes of density of electronic states near the Fermi energy level, which are induced by the changes of the Mo-S and Mo-Mo bonds upon bending. This report provides a new design methodology to improve the catalytic activity of catalysts based on two-dimensional transition metal dichalcogenides through a simple mechanical bending.

  15. The enhancement activities of histidyl-histidine in some prebiotic reactions

    NASA Technical Reports Server (NTRS)

    Shen, C.; Lazcano, A.; Oro, J.

    1990-01-01

    The prebiotic synthesis of His and its dimer has led us to study the possible catalytic properties of His-His. The enhancing effect of His-His has been tested in the dephosphorylation of dAMP, the hydrolysis of oligo(A)12, and the oligomerization of 2'3'-cAMP.

  16. Enhancement of the Chemiluminescence Response of Enzymatic Reactions by Plasmonic Surfaces for Biosensing Applications.

    PubMed

    Abel, Biebele; Odukoya, Babatunde; Mohammed, Muzaffer; Aslan, Kadir

    We report the enhancement of chemiluminescence response of horseradish peroxidase (HRP) in bioassays by plasmonic surfaces, which are comprised of (i) silver island films (SIFs) and (ii) metal thin films (silver, gold, copper, and nickel, 1 nm thick) deposited onto glass slides. A model bioassay, based on the interactions of avidin-modified HRP with a monolayer of biotinylated poly(ethylene-glycol)-amine, was employed to evaluate the ability of plasmonic surfaces to enhance chemiluminescence response of HRP. Chemiluminescence response of HRP in model bioassays were increased up to ~3.7-fold as compared to the control samples (i.e. glass slides without plasmonic nanoparticles), where the largest enhancement of the chemiluminescence response was observed on SIFs with high loading. These findings allowed us to demonstrate the use of SIFs (high loading) for the detection of a biologically relevant target protein (glial fibrillary acidic protein or GFAP), where the chemiluminescence response of the standard bioassay for GFAP was enhanced up to ~50% as compared to bioassay on glass slides.

  17. Mucosal acid causes gastric mucosal microcirculatory disturbance in nonsteroidal anti-inflammatory drug-treated rats.

    PubMed

    Funatsu, Toshiyuki; Chono, Koji; Hirata, Takuya; Keto, Yoshihiro; Kimoto, Aishi; Sasamata, Masao

    2007-01-05

    The mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) suppress gastric mucosal blood flow is not fully understood, although the depletion of mucosal prostaglandin E2 has been proposed as one possible explanation. We investigated the role of gastric acid on gastric mucosal blood flow in NSAID-treated rats. A rat stomach was mounted in an ex vivo chamber, and gastric mucosal blood flow was measured sequentially in a 5-mm2 area of the gastric corpus using a scanning laser Doppler perfusion image system. Results showed that diclofenac (5 mg/kg s.c.) and indomethacin (10 mg/kg s.c.) did not affect gastric mucosal blood flow, although both strongly decreased mucosal prostaglandin E2 when saline was instilled into the gastric chamber. On replacement of the saline in the chamber with 100 mM hydrochloric acid, these drugs caused a decrease in gastric mucosal blood flow levels within 30 min. The specific cyclooxygenase (COX)-2 inhibitors celecoxib (50 mg/kg s.c.) and rofecoxib (25 mg/kg s.c.) did not affect mucosal prostaglandin E2 level, nor did they decrease gastric mucosal blood flow, even when hydrochloric acid was added to the chamber. Furthermore, measurement of vasoconstrictive factors present in the mucosa showed that endothelin-1 levels increased after administration of diclofenac s.c. in the presence of intragastric hydrochloric acid. This indicates that the presence of mucosal hydrochloric acid plays an important role in the NSAID-induced decrease in gastric mucosal blood flow, while the COX-1-derived basal prostaglandin E2, which is unlikely to control gastric mucosal blood flow itself, protects microcirculatory systems from mucosal hydrochloric acid.

  18. Lansoprazole induces mucosal protection through gastrin receptor-dependent up-regulation of cyclooxygenase-2 in rats.

    PubMed

    Tsuji, Shingo; Sun, Wei-Hao; Tsujii, Masahiko; Kawai, Naoki; Kimura, Arata; Kakiuchi, Yoshimi; Yasumaru, Shoichi; Komori, Masato; Murata, Hiroaki; Sasaki, Yutaka; Kawano, Sunao; Hori, Masatsugu

    2002-12-01

    Proton pump inhibitors (PPIs) are antiulcer agents that have both gastric antisecretory and mucosal protective actions. The mechanisms of PPI-induced gastric mucosal protection are not known. The present study was designed to examine the mechanism for lansoprazole-induced gastric mucosal protection in rats. Rats were given 0.5, 5, and 50 mg/kg/day lansoprazole alone or both lansoprazole (50 mg/kg/day) and a specific gastrin receptor antagonist 3R-1-(2,2-diethoxyethyl)-((4-methylphenyl)amino-carbonyl methyl)-3-((4-methylphenyl)ureidoindoline-2- one) (AG-041R) (3, 10, and 30 mg/kg/day) for 14 days. Serum gastrin concentrations were measured. The expression of cyclooxygenases (COX-1 and COX-2) in the gastric mucosa was analyzed using Western blotting and immunohistochemical staining. Another series of rats was used to examine the 1) levels of prostaglandin (PG) E2 in gastric mucosa, 2) influences of the drugs on gastric damage caused by absolute ethanol, and 3) effects of a COX-2-specific inhibitor on PGE2 in the gastric mucosa and the mucosal protection afforded by lansoprazole. Lansoprazole dose dependently increased the serum gastrin concentration and enhanced the mucosal expression of COX-2 but not that of COX-1. Lansoprazole increased gastric mucosal PGE2 and reduced gastric damage caused by ethanol. Concomitant administration of AG-041R abolished the lansoprazole-induced COX-2 expression, and increased mucosal PGE2 and mucosal protection. A specific COX-2 inhibitor blocked the lansoprazole-induced increase in mucosal PGE2 and mucosal protection. Activation of gastrin receptors by endogenous gastrin has a pivotal role in the effects of lansoprazole on COX-2 up-regulation and mucosal protection in the rat stomach.

  19. Mucosal Vaccine Development Based on Liposome Technology

    PubMed Central

    Norling, Karin; Bally, Marta; Höök, Fredrik

    2016-01-01

    Immune protection against infectious diseases is most effective if located at the portal of entry of the pathogen. Hence, there is an increasing demand for vaccine formulations that can induce strong protective immunity following oral, respiratory, or genital tract administration. At present, only few mucosal vaccines are found on the market, but recent technological advancements and a better understanding of the principles that govern priming of mucosal immune responses have contributed to a more optimistic view on the future of mucosal vaccines. Compared to live attenuated vaccines, subcomponent vaccines, most often protein-based, are considered safer, more stable, and less complicated to manufacture, but they require the addition of nontoxic and clinically safe adjuvants to be effective. In addition, another limiting factor is the large antigen dose that usually is required for mucosal vaccines. Therefore, the combination of mucosal adjuvants with the recent progress in nanoparticle technology provides an attractive solution to these problems. In particular, the liposome technology is ideal for combining protein antigen and adjuvant into an effective mucosal vaccine. Here, we describe and discuss recent progress in nanoparticle formulations using various types of liposomes that convey strong promise for the successful development of the next generation of mucosal vaccines. PMID:28127567

  20. Treatment of oral mucositis due to chemotherapy

    PubMed Central

    Bagán-Sebastián, José V

    2016-01-01

    Introduction The management of oral mucositis is a challenge, due to its complex biological nature. Over the last 10 years, different strategies have been developed for the management of oral mucositis caused by chemotherapy in cancer patients. Material and Methods An exhaustive search was made of the PubMed-Medline, Cochrane Library and Scopus databases, crossing the key words “oral mucositis”, “prevention” and “treatment” with the terms “chemotherapy” and “radiotherapy” by means of the boolean operators “AND” and “NOT”. A total of 268 articles were obtained, of which 96 met the inclusion criteria. Results Several interventions for the prevention of oral mucositis, such as oral hygiene protocols, amifostine, benzidamine, calcium phosphate, cryotherapy and iseganan, among others, were found to yield only limited benefits. Other studies have reported a decrease in the appearance and severity of mucositis with the use of cytoprotectors (sucralfate, oral glutamine, hyaluronic acid), growth factors, topical polyvinylpyrrolidone, and low power laser irradiation. Conclusions Very few interventions of confirmed efficacy are available for the management of oral mucositis due to chemotherapy. However, according to the reviewed literature, the use of palifermin, cryotherapy and low power laser offers benefits, reducing the incidence and severity of oral mucositis – though further studies are needed to confirm the results obtained. Key words:Chemotherapy-Induced Oral Mucositis Treatment. PMID:27034762

  1. The mucosal immune system for vaccine development.

    PubMed

    Lamichhane, Aayam; Azegamia, Tatsuhiko; Kiyonoa, Hiroshi

    2014-11-20

    Mucosal surfaces are continuously exposed to the external environment and therefore represent the largest lymphoid organ of the body. In the mucosal immune system, gut-associated lymphoid tissues (GALTs), including Peyer's patches and isolated lymphoid follicles, play an important role in the induction of antigen-specific immune responses in the gut. GALTs have unique organogenesis characteristics and interact with the network of dendritic cells and T cells for the simultaneous induction and regulation of IgA responses and oral tolerance. In these lymphoid tissues, antigens are up taken by M cells in the epithelial layer, and antigen-specific immune responses are subsequently initiated by GALT cells. Nasopharynx- and tear-duct-associated lymphoid tissues (NALTs and TALTs) are key organized lymphoid structures in the respiratory tract and ocular cavities, respectively, and have been shown to interact with each other. Mucosal surfaces are also characterized by host-microbe interactions that affect the genesis and maturation of mucosa-associated lymphoid tissues and the induction and regulation of innate and acquired mucosal immune responses. Because most harmful pathogens enter the body through mucosal surfaces by ingestion, inhalation, or sexual contact, the mucosa is a candidate site for vaccination. Mucosal vaccination has some physiological and practical advantages, such as decreased costs and reduced risk of needle-stick injuries and transmission of bloodborne diseases, and it is painless. Recently, the application of modern bioengineering and biochemical engineering technologies, including gene transformation and manipulation systems, resulted in the development of systems to express vaccine antigens in transgenic plants and nanogels, which will usher in a new era of delivery systems for mucosal vaccine antigens. In this review, based on some of our research group's thirty seven years of progress and effort, we highlight the unique features of mucosal immune

  2. Performance Enhancement and Side Reactions in Rechargeable Nickel-Iron Batteries with Nanostructured Electrodes.

    PubMed

    Lei, Danni; Lee, Dong-Chan; Magasinski, Alexandre; Zhao, Enbo; Steingart, Daniel; Yushin, Gleb

    2016-01-27

    We report for the first time a solution-based synthesis of strongly coupled nanoFe/multiwalled carbon nanotube (MWCNT) and nanoNiO/MWCNT nanocomposite materials for use as anodes and cathodes in rechargeable alkaline Ni-Fe batteries. The produced aqueous batteries demonstrate very high discharge capacities (800 mAh gFe(-1) at 200 mA g(-1) current density), which exceed that of commercial Ni-Fe cells by nearly 1 order of magnitude at comparable current densities. These cells also showed the lack of any "activation", typical in commercial batteries, where low initial capacity slowly increases during the initial 20-50 cycles. The use of a highly conductive MWCNT network allows for high-capacity utilization because of rapid and efficient electron transport to active metal nanoparticles in oxidized [such as Fe(OH)2 or Fe3O4] states. The flexible nature of MWCNTs accommodates significant volume changes taking place during phase transformation accompanying reduction-oxidation reactions in metal electrodes. At the same time, we report and discuss that high surface areas of active nanoparticles lead to multiple side reactions. Dissolution of Fe anodes leads to reprecipitation of significantly larger anode particles. Dissolution of Ni cathodes leads to precipitation of Ni metal on the anode, thus blocking transport of OH(-) anions. The electrolyte molarity and composition have a significant impact on the capacity utilization and cycling stability.

  3. ENHANCEMENT OF EQUILIBRIUMSHIFT IN DEHYDROGENATION REACTIONS USING A NOVEL MEMBRANE REACTOR

    SciTech Connect

    Shamsuddin Ilias, Ph.d., P.E.; Franklin G. King, D.Sc.

    2001-02-13

    With the advances in new inorganic materials and processing techniques, there has been renewed interest in exploiting the benefits of membranes in many industrial applications. Inorganic and composite membranes are being considered as potential candidates for use in membrane-reactor configuration for effectively increasing reaction rate, selectivity and yield of equilibrium limited reactions. To investigate the usefulness of a palladium-ceramic composite membrane in a membrane reactor-separator configuration, we investigated the dehydrogenation of cyclohexane by equilibrium shift. A two-dimensional pseudo-homogeneous reactor model was developed to study the dehydrogenation of cyclohexane by equilibrium shift in a tubular membrane reactor. Radial diffusion was considered to account for the concentration gradient in the radial direction due to permeation through the membrane. For a dehydrogenation reaction, the feed stream to the reaction side contained cyclohexane and argon, while the separation side used argon as the sweep gas. Equilibrium conversion for dehydrogenation of cyclohexane is 18.7%. The present study showed that 100% conversion could be achieved by equilibrium shift using Pd-ceramic membrane reactor. For a feed containing cyclohexane and argon of 1.64 x 10{sup -6} and 1.0 x 10{sup -3} mol/s, over 98% conversion could be readily achieved. The dehydrogenation of cyclohexane was also experimentally investigated in a palladium-ceramic membrane reactor. The Pd-ceramic membrane was fabricated by electroless deposition of palladium on ceramic substrate. The performance of Pd-ceramic membrane was compared with a commercially available hydrogen-selective ceramic membrane. From limited experimental data it was observed that by appropriate choice of feed flow rate and sweep gas rate, the conversion of cyclohexane to benzene and hydrogen can increased to 56% at atmospheric pressure and 200 C in a Pd-ceramic membrane reactor. In the commercial ceramic membrane

  4. Animal models of mucositis: implications for therapy.

    PubMed

    Bowen, Joanne M; Gibson, Rachel J; Keefe, Dorothy M K

    2011-01-01

    Alimentary mucositis is a major acute complication in the clinical setting, occurring in a large percentage of patients undergoing cytotoxic therapy. One of the major problems with alimentary mucositis is that the underlying mechanisms behind its development are not entirely understood, which makes it extremely difficult to develop effective interventions. Animal models provide a critical source of knowledge when sampling from patients is unavailable or interventions are yet to be fully tested. This review focuses on the animal models used to increase our understanding of the mechanisms of mucositis and translate new antimucotoxic agents into clinical trials.

  5. Oral mucositis. A complication of radiotherapy

    SciTech Connect

    Rider, C.A. )

    1990-11-01

    Oral mucositis is a complication of head and neck radiotherapy. It is understood what causes the inflammation and what biological tissue changes occur, however, a definite cure for oral mucositis has not yet been found. Supportive treatments, analgesics, antimicrobials and anti-inflammatory agents have been prescribed, none of which has been a thorough measure of treatment. An effective cure for oral mucositis is still in the midst of scientific research. In the interim local palliative treatments will help to alleviate the patients', debilitating symptoms.

  6. Design Paradigm Utilizing Reversible Diels-Alder Reactions to Enhance the Mechanical Properties of 3D Printed Materials.

    PubMed

    Davidson, Joshua R; Appuhamillage, Gayan A; Thompson, Christina M; Voit, Walter; Smaldone, Ronald A

    2016-07-06

    A design paradigm is demonstrated that enables new functional 3D printed materials made by fused filament fabrication (FFF) utilizing a thermally reversible dynamic covalent Diels-Alder reaction to dramatically improve both strength and toughness via self-healing mechanisms. To achieve this, we used as a mending agent a partially cross-linked terpolymer consisting of furan-maleimide Diels-Alder (fmDA) adducts that exhibit reversibility at temperatures typically used for FFF printing. When this mending agent is blended with commercially available polylactic acid (PLA) and printed, the resulting materials demonstrate an increase in the interfilament adhesion strength along the z-axis of up to 130%, with ultimate tensile strength increasing from 10 MPa in neat PLA to 24 MPa in fmDA-enhanced PLA. Toughness in the z-axis aligned prints increases by up to 460% from 0.05 MJ/m(3) for unmodified PLA to 0.28 MJ/m(3) for the remendable PLA. Importantly, it is demonstrated that a thermally reversible cross-linking paradigm based on the furan-maleimide Diels-Alder (fmDA) reaction can be more broadly applied to engineer property enhancements and remending abilities to a host of other 3D printable materials with superior mechanical properties.

  7. Enhanced osteogenic differentiation of MC3T3-E1 on rhBMP-2-immobilized titanium via click reaction.

    PubMed

    Kim, Eun-Cheol; Kim, Tae-Hee; Jung, Jae-Hoon; Hong, Sung Ok; Lee, Deok-Won

    2014-03-15

    In the present study, we report about the efficacy of titanium surface-immobilized with bone morphogenetic protein-2 (BMP-2) via click reaction on enhanced osteogenic differentiation of MC3T3-E1 cells. The surface was characterized by static contact angles and XPS measurements, which indicated that pristine titanium (Ti-1) was successfully surface-modified via click chemistry (aminated titanium, Ti-4). By quantitative analysis of heparin immobilized on aminated titanium (Ti-4), we found that the Ti-4 can be used as a good candidate to immobilize biomolecules such as heparin. BMP-2 from titanium immobilized with BMP-2 (Ti-6) was released for a period of 28 days in a sustained manner. The highest proliferation rate of MC3T3-E1 cells was observed on Ti-6. Through in vitro tests including alkaline phosphatase (ALP) activity, calcium deposition and real-time polymerase chain reaction (real-time PCR), we found that Ti-6 can be used as a good implant to enhance the osteogenic differentiation of MC3T3-E1 cells.

  8. Reaction of cyclohexylamine with hypochlorite and enhancement of oxidation of plasma sulfhydryl groups by hypochlorite in vitro.

    PubMed

    Hu, M L; Tsai, H H

    1998-01-01

    In this study we investigated the reaction of cyclamate and its major metabolite, cyclohexylamine (CyhNH2), with NaOCl. NaOCl at 100 microM was allowed to react with various concentrations of cyclamate and CyhNH2, and the reactivity was compared with those of reduced glutathione (GSH) and ascorbic acid. The results showed that CyhNH2 was less reactive with NaOCl than GSH but was slightly more reactive than ascorbic acid at concentrations below 50 microM. CyhNH2 at 75 and 100 microM did not further decrease NaOCl. Cyclamate was much less reactive than CyhNH2, with only 43% loss in NaOCl at 100 microM cyclamate. When human blood plasma was incubated with 0.75 microM NaOCl, inclusion of CyhNH2 enhanced oxidation of sulfhydryl groups in a concentration-dependent manner, with complete oxidation of SH groups at 7.5 mM CyhNH2. Cyclamate had no effect. This enhancement by CyhNH2 suggests the formation of reactive products from the reaction of CyhNH2 with NaOCl. Absorption spectra demonstrated that reaction of CyhNH2 with NaOCl at pH 7.4 produced N-monochloramine, as evidenced by the appearance of a new peak at 245 nm and by the disappearance of the 292-nm peak of NaOCl. Cyclamate, which contains a sulfamic acid instead of a primary amine, also reacted with NaOCl at pH 7.4, but the reaction was much less pronounced and the product was probably not monochloramine since the peak was at 270 nm rather than at 245 nm. Because cyclamate is an important sweetener in many countries for people with diabetes mellitus, the possibility exists that CyhNH2 may enhance oxidation of important proteins by HOCl/OCl-.

  9. Hypersensitivity to acid is associated with impaired esophageal mucosal integrity in patients with gastroesophageal reflux disease with and without esophagitis.

    PubMed

    Weijenborg, Pim W; Smout, André J P M; Verseijden, Caroline; van Veen, Henk A; Verheij, Joanne; de Jonge, Wouter J; Bredenoord, Albert J

    2014-08-01

    Increased esophageal sensitivity and impaired mucosal integrity have both been described in patients with gastroesophageal reflux disease, but the relationship between hypersensitivity and mucosal integrity is unclear. The aim of the present study was to investigate acid sensitivity in patients with erosive and nonerosive reflux disease and control subjects to determine the relation with functional esophageal mucosal integrity changes as well as to investigate cellular mechanisms of impaired mucosal integrity in these patients. In this prospective experimental study, 12 patients with nonerosive reflux disease, 12 patients with esophagitis grade A or B, and 11 healthy control subjects underwent an acid perfusion test and upper endoscopy. Mucosal integrity was measured during endoscopy by electrical tissue impedance spectroscopy and biopsy specimens were analyzed in Ussing chambers for transepithelial electrical resistance, transepithelial permeability and gene expression of tight junction proteins and filaggrin. Patients with nonerosive reflux disease and esophagitis were more sensitive to acid perfusion compared with control subjects, having a shorter time to perception of heartburn and higher perceived intensity of heartburn. In reflux patients, enhanced acid sensitivity was associated with impairment of in vivo and vitro esophageal mucosal integrity. Mucosal integrity was significantly impaired in patients with esophagitis, displaying higher transepithelial permeability and lower extracellular impedance. Although no significant differences in the expression of tight junction proteins were found in biopsies among patient groups, mucosal integrity parameters in reflux patients correlated negatively with the expression of filaggrin. In conclusion, sensitivity to acid is enhanced in patients with gastroesophageal reflux disease, irrespective of the presence of erosions, and is associated with impaired esophageal mucosal integrity. Mucosal integrity of the esophagus

  10. Mucosal transmission and pathogenesis of chronic wasting disease in ferrets

    PubMed Central

    Perrott, Matthew R.; Sigurdson, Christina J.; Mason, Gary L.

    2013-01-01

    Chronic wasting disease (CWD) of cervids is almost certainly transmitted by mucosal contact with the causative prion, whether by direct (animal-to-animal) or indirect (environmental) means. Yet the sites and mechanisms of prion entry remain to be further understood. This study sought to extend this understanding by demonstrating that ferrets exposed to CWD via several mucosal routes developed infection, CWD prion protein (PrPCWD) amplification in lymphoid tissues, neural invasion and florid transmissible spongiform encephalopathy lesions resembling those in native cervid hosts. The ferrets developed extensive PrPCWD accumulation in the nervous system, retina and olfactory epithelium, with lesser deposition in tongue, muscle, salivary gland and the vomeronasal organ. PrPCWD accumulation in mucosal sites, including upper respiratory tract epithelium, olfactory epithelium and intestinal Peyer’s patches, make the shedding of prions by infected ferrets plausible. It was also observed that regionally targeted exposure of the nasopharyngeal mucosa resulted in an increased attack rate when compared with oral exposure. The latter finding suggests that nasal exposure enhances permissiveness to CWD infection. The ferret model has further potential for investigation of portals for initiation of CWD infection. PMID:23100363

  11. Atomic Layer-by-Layer Deposition of Platinum on Palladium Octahedra for Enhanced Catalysts toward the Oxygen Reduction Reaction

    DOE PAGES

    Park, Jinho; Zhang, Lei; Choi, Sang-Il; ...

    2015-02-08

    We systematically evaluated two different approaches to the syntheses of Pd@PtnL (n = 2–5) core–shell octahedra. We initially prepared the core–shell octahedra using a polyol-based route by titrating a Pt(IV) precursor into the growth solution containing Pd octahedral seeds at 200 °C through the use of a syringe pump. The number of Pt atomic layers could be precisely controlled from two to five by increasing the volume of the precursor solution while fixing the amount of seeds. We then demonstrated the synthesis of Pd@PtnL octahedra using a water-based route at 95 °C through the one-shot injection of a Pt(II) precursor.more » Due to the large difference in reaction temperature, the Pd@PtnL octahedra obtained via the water-based route showed sharper corners than their counterparts obtained through the polyol-based route. When compared to a commercial Pt/C catalyst based upon 3.2 nm Pt particles, the Pd@PtnL octahedra prepared using both methods showed similar remarkable enhancement in terms of activity (both specific and mass) and durability toward the oxygen reduction reaction. These calculations based upon periodic, self-consistent density functional theory suggested that the enhancement in specific activity for the Pd@PtnL octahedra could be attributed to the destabilization of OH on their PtnL*/Pd(111) surface relative to the {111} and {100} facets exposed on the surface of Pt/C. Finally. the destabilization of OH facilitates its hydrogenation, which was found to be the rate-limiting step of the oxygen reduction reaction on all these surfaces.« less

  12. Atomic Layer-by-Layer Deposition of Platinum on Palladium Octahedra for Enhanced Catalysts toward the Oxygen Reduction Reaction

    SciTech Connect

    Park, Jinho; Zhang, Lei; Choi, Sang-Il; Roling, Luke T.; Lu, Ning; Herron, Jeffrey A.; Xie, Shuifen; Wang, Jinguo; Kim, Moon J.; Mavrikakis, Manos; Xia, Younan

    2015-02-08

    We systematically evaluated two different approaches to the syntheses of Pd@PtnL (n = 2–5) core–shell octahedra. We initially prepared the core–shell octahedra using a polyol-based route by titrating a Pt(IV) precursor into the growth solution containing Pd octahedral seeds at 200 °C through the use of a syringe pump. The number of Pt atomic layers could be precisely controlled from two to five by increasing the volume of the precursor solution while fixing the amount of seeds. We then demonstrated the synthesis of Pd@PtnL octahedra using a water-based route at 95 °C through the one-shot injection of a Pt(II) precursor. Due to the large difference in reaction temperature, the Pd@PtnL octahedra obtained via the water-based route showed sharper corners than their counterparts obtained through the polyol-based route. When compared to a commercial Pt/C catalyst based upon 3.2 nm Pt particles, the Pd@PtnL octahedra prepared using both methods showed similar remarkable enhancement in terms of activity (both specific and mass) and durability toward the oxygen reduction reaction. These calculations based upon periodic, self-consistent density functional theory suggested that the enhancement in specific activity for the Pd@PtnL octahedra could be attributed to the destabilization of OH on their PtnL*/Pd(111) surface relative to the {111} and {100} facets exposed on the surface of Pt/C. Finally. the destabilization of OH facilitates its hydrogenation, which was found to be the rate-limiting step of the oxygen reduction reaction on all these surfaces.

  13. Self-reported food intolerance and mucosal reactivity after rectal food protein challenge in patients with rheumatoid arthritis.

    PubMed

    Lidén, M; Kristjánsson, G; Valtysdottir, S; Venge, P; Hällgren, R

    2010-08-01

    A dietary link to rheumatoid arthritis (RA) has been suspected and an influence on arthritic symptoms by different diets has been reported. Our primary aim was to record the self-experienced adverse food reactions in patients with RA. A secondary aim was to relate self-experienced adverse reactions to dairy produce and wheat to the local mucosal reactivity observed after rectal challenge with cow's milk protein (CM) and wheat gluten. A questionnaire about self-experienced adverse reaction to food was sent to 347 RA patients. Rectal challenge with CM and gluten was performed in 27 of these patients and in healthy controls (n = 18). After a 15-h challenge the mucosal production of nitric oxide (NO) and the mucosal release of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were measured by using the mucosal patch technique. Twenty-seven per cent of the RA patients reported food intolerance (FI) to various foods, and in particular to CM, meat, and wheat gluten. Strong mucosal reactivity to CM was observed in 11% of the patients. Moderately increased mucosal reactivity to CM and gluten was found in 22% and 33%, respectively, of the patients. No relationship was found between self-experienced adverse reactions to CM or gluten and mucosal reactivity to these proteins. Perceived FI is reported frequently by RA patients, with a prevalence similar to that reported previously in the general population. Mucosal reactivity to CM and gluten is seen in a minor fraction of RA patients and is not related to the frequently perceived intolerance to these proteins.

  14. Radiation treatment breaks and ulcerative mucositis in head and neck cancer.

    PubMed

    Russo, Gregory; Haddad, Robert; Posner, Marshall; Machtay, Mitchell

    2008-08-01

    Unplanned radiation treatment breaks and prolongation of the radiation treatment time are associated with lower survival and locoregional control rates when radiotherapy or concurrent chemoradiotherapy is used in the curative treatment of head and neck cancer. Treatment of head and neck cancer is intense, involving high-dose, continuous radiotherapy, and often adding chemotherapy to radiotherapy. As the intensity of treatment regimens has escalated in recent years, clinical outcomes generally have improved. However, more intensive therapy also increases the incidence of treatment-related toxicities, particularly those impacting the mucosal lining of the oral cavity, pharynx, and cervical esophagus, and results in varying degrees of ulcerative mucositis. Ulcerative mucositis is a root cause of unscheduled radiation treatment breaks, which prolongs the total radiation treatment time. Alterations in radiotherapy and chemotherapy, including the use of continuous (i.e., 7 days/week) radiotherapy to ensure constant negative proliferative pressure, may improve efficacy outcomes. However, these approaches also increase the incidence of ulcerative mucositis, thereby increasing the incidence of unplanned radiation treatment breaks. Conversely, the reduction of ulcerative mucositis to minimize unplanned breaks in radiotherapy may enhance not only tolerability, but also efficacy outcomes. Several strategies to prevent ulcerative mucositis in radiotherapy for head and neck cancer have been evaluated, but none have demonstrated strong efficacy. Continued investigation is needed to identify superior radiation treatment regimens, technology, and supportive care that reduce unplanned radiation treatment breaks with the goal of improving clinical outcomes in head and neck cancer.

  15. ALTERATIONS IN MUCOSAL IMMUNITY IDENTIFIED IN THE COLON OF PATIENTS WITH IRRITABLE BOWEL SYNDROME

    PubMed Central

    Aerssens, Jeroen; Camilleri, Michael; Talloen, Willem; Thielemans, Leen; Göhlmann, Hinrich W. H.; Wyngaert, Ilse Van den; Thielemans, Theo; de Hoogt, Ronald; Andrews, Christopher N.; Bharucha, Adil E.; Carlson, Paula J.; Busciglio, Irene; Burton, Duane D.; Smyrk, Thomas; Urrutia, Raul; Coulie, Bernard

    2008-01-01

    BACKGROUND & AIMS Irritable bowel syndrome (IBS) has been associated with mucosal dysfunction,, mild inflammation, and altered colonic bacteria. We used microarray expression profiling of sigmoid colon mucosa to assess whether there are stably expressed sets of genes that suggest there are objective molecular biomarkers associated with IBS. METHODS Gene expression profiling was performed using Affymetrix GeneChips with RNA from sigmoid colon mucosal biopsies from 36 IBS patients and 25 healthy control subjects. RTQ-PCR was used to confirm the data in 12 genes of interest. Statistical methods for microarray data were applied to search for differentially expressed genes, and to assess the stability of molecular signatures in IBS patients. RESULTS Mucosal gene expression profiles were consistent across different sites within the sigmoid colon and were stable on repeat biopsy over ~3 months. Differentially expressed genes suggest functional alterations of several components of the host mucosal immune response to microbial pathogens. The most strikingly increased expression involved a yet uncharacterized gene, DKFZP564O0823. Identified specific genes suggest the hypothesis that molecular signatures may enable distinction of a subset of IBS patients from healthy controls. Using 75% of the biopsies as a validation set to develop a gene profile, the test set (25%) was correctly predicted with ~70% accuracy. CONCLUSIONS Mucosal gene expression analysis shows there are relatively stable alterations in colonic mucosal immunity in IBS. These molecular alterations provide the basis to test the hypothesis that objective biomarkers may be identified in IBS and enhance understanding of the disease. PMID:18237869

  16. Enhancing the free corrosion dealloying rate with a catalytically driven reaction.

    PubMed

    Deng, Ziling; Detsi, Eric

    2017-08-24

    Despite its high popularity, chemical dealloying that is widely used for the fabrication of nanoporous metals is a relatively slow process: dealloying a few milligrams of bulk material may take from several hours up to a few days, depending on the material system. Raising the temperature of the corroding medium is a common approach to speed up the dealloying process. However, high temperatures cause undesired ligament growth in dealloyed materials. Here we report for the first time the use of a catalytically driven reaction to speed up the dealloying process at ambient temperature and pressure. To demonstrate the concept, we show that the free corrosion dealloying of a silver-aluminum alloy is significantly faster with the help of a platinum catalyst. More importantly, the corresponding characteristic nanostructured size is much smaller than that without a catalyst. Our finding is expected to play a central role in scaling up the dealloying process from the laboratory to the industrial scale.

  17. Systems biology approaches to enhance our understanding of drug hypersensitivity reactions.

    PubMed

    Perkins, J R; Barrionuevo, E; Ranea, J A; Blanca, M; Cornejo-Garcia, J A

    2014-12-01

    Hypersensitivity drug reactions (HDRs) encompass a wide spectrum of unpredictable clinical entities. They represent an important health problem, affecting people of all ages, and lead to a large strain on the public health system. Here, we summarize experiments that use high-throughput genomics technologies to investigate HDRs. We also introduce the field of systems biology as a relatively recent discipline concerned with the integration and analysis of high-throughput data sets such as DNA microarrays and next-generation sequencing data. We describe previous studies that have applied systems biology techniques to related fields such as allergy and asthma. Finally, we present a number of potential applications of systems biology to the study of HDRs, in order to make the reader aware of the types of analyses that can be performed and the insights that can be gained through their application. © 2014 John Wiley & Sons Ltd.

  18. Effects of iron type in Fenton reaction on mineralization and biodegradability enhancement of hazardous organic compounds.

    PubMed

    Khan, Eakalak; Wirojanagud, Wanpen; Sermsai, Nawarat

    2009-01-30

    The mineralization and biodegradability increase and their combination of two traditional and two relatively new organic contaminants by Fenton reagents with three different types of iron, Fe(2+), Fe(3+), and Fe(0) were investigated. The traditional contaminants examined were trichloroethene (TCE) and 2,4-dichlorophenol (2,4-DCP) while 1,4-dioxane (1,4-D) and 1,2,3-trichloropropane (TCP) were studied for the relatively new contaminants. The mineralization and biodegradability were represented by dissolved organic carbon (DOC) reduction and the ratio of biodegradable dissolved organic carbon and DOC, respectively. For all four contaminants, Fenton reagent using Fe(2+) was more effective in the DOC reduction than Fenton reagents using Fe(3+) and Fe(0) in most cases. The types of Fe that provided maximum biodegradability increase were not the same for all four compounds, Fe(3+) for TCE, Fe(0) for 2,4-DCP, Fe(2+) for 1,4-D, and Fe(3+) for TCP. When the combination of DOC elimination and biodegradability increase (least refractory fraction) was considered, Fe(2+) was the best choice except for 2,4-DCP which was susceptible to Fe(0) catalyzed Fenton reagent the most. The least refractory fractions remaining after 120 min of reaction were 20-25% for TCE, 2,4-DCP, and TCP and 30-40% for 1,4-D. The iron type in Fenton reaction also affected the type of mineralization kinetics of TCE, 2,4-DCP, and TCP as well as the types of degradation by-products of these contaminants. Some of the by-products found, such as isopropanol and propionic aldehyde, which were produced from Fe(0) catalyzed Fenton degradation of TCP, have not been previously reported.

  19. Elderly Fallers Enhance Dynamic Stability Through Anticipatory Postural Adjustments during a Choice Stepping Reaction Time

    PubMed Central

    Tisserand, Romain; Robert, Thomas; Chabaud, Pascal; Bonnefoy, Marc; Chèze, Laurence

    2016-01-01

    In the case of disequilibrium, the capacity to step quickly is critical to avoid falling in elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT), where elderly fallers (F) take longer to step than elderly non-fallers (NF). However, the reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA) that elderly F develop in a stepping context and their consequences on the dynamic stability. Forty-four community-dwelling elderly subjects (20 F and 24 NF) performed a CSRT where kinematics and ground reaction forces were collected. Variables were analyzed using two-way repeated measures ANOVAs. Results for F compared to NF showed that stepping time is elongated, due to a longer APA phase. During APA, they seem to use two distinct balance strategies, depending on the axis: in the anteroposterior direction, we measured a smaller backward movement and slower peak velocity of the center of pressure (CoP); in the mediolateral direction, the CoP movement was similar in amplitude and peak velocity between groups but lasted longer. The biomechanical consequence of both strategies was an increased margin of stability (MoS) at foot-off, in the respective direction. By elongating their APA, elderly F use a safer balance strategy that prioritizes dynamic stability conditions instead of the objective of the task. Such a choice in balance strategy probably comes from muscular limitations and/or a higher fear of falling and paradoxically indicates an increased risk of fall. PMID:27965561

  20. Anionic surfactants enhance click reaction-mediated protein conjugation with ubiquitin.

    PubMed

    Schneider, Daniel; Schneider, Tatjana; Aschenbrenner, Joos; Mortensen, Franziska; Scheffner, Martin; Marx, Andreas

    2016-03-01

    The Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) has become increasingly important in the conjugation chemistry of biomolecules. For example, it is an efficient and convenient method to generate defined ubiquitin-protein conjugates. Here, we investigate the effect of surfactants on the efficiency of CuAAC for chemical protein ubiquitylation. We found that anionic surfactants enhance conjugate formation by up to 10-fold resulting in high yields even at low (i.e., micromolar) concentrations of the reactants. Notably, the herein investigated conjugates are functional and thus properly folded. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Uniform Gold Nanoparticles Decorated {001}-Faceted Anatase TiO2 Nanosheets for Enhanced Solar Light Photocatalytic Reactions.

    PubMed

    Shi, Huimin; Zhang, Shi; Zhu, Xupeng; Liu, Yu; Wang, Tao; Jiang, Tian; Zhang, Guanhua; Duan, Huigao

    2017-10-09

    The {001}-faceted anatase TiO2 micro/nanocrystals have been widely investigated for enhancing the photocatalysis and photoelectrochemical performance of TiO2 nanostructures but their practical applications still require improved energy conversion efficiency under solar light and enhanced cycling stability. In this work, we demonstrate the controlled growth of ultrathin {001}-faceted anatase TiO2 nanosheets on flexible carbon cloth for enhancing the cycling stability, and the solar light photocatalytic performance of the synthesized TiO2 nanosheets can be significantly improved by decorating with vapor-phase deposited uniformly-distributed plasmonic gold nanoparticles. The fabricated Au-TiO2 hybrid system shows an eight-fold solar light photocatalysis enhancement factor in photo-degrading Rhodamine B, a high photocurrent density of 300 μA cm-2 under the illumination of AM 1.5G, and 100% recyclability under consecutive long-term cycling measurement. Combined with electromagnetic simulations and systematic control experiments, it is believed that the tandem type separation and transition of plasmon-induced hot electrons from Au nanoparticles to {001} facet of anatase TiO2, and then to neighboring {101} facet is responsible to the enhanced solar light photochemical performance of the hybrid system. The Au-TiO2 nanosheet system well addresses the problems of limited solar-light response of anatase TiO2 and fast recombination of photo-generated electron-hole pairs, representing a promising high-performance recyclable solar light responded system for practical photocatalytic reactions.

  2. Enhancing the specificity and efficiency of polymerase chain reaction using polyethyleneimine-based derivatives and hybrid nanocomposites

    PubMed Central

    Tong, Weiwei; Cao, Xueyan; Wen, Shihui; Guo, Rui; Shen, Mingwu; Wang, Jianhua; Shi, Xiangyang

    2012-01-01

    There is a general necessity to improve the specificity and efficiency of the polymerase chain reaction (PCR), and exploring the PCR-enhancing mechanism still remains a great challenge. In this paper we report the use of branched polyethyleneimine (PEI)-based derivatives and hybrid nanocomposites as a novel class of enhancers to improve the specificity and efficiency of a nonspecific PCR system. We show that the surface-charge polarity of PEI and PEI derivatives plays a major role in their effectiveness to enhance the PCR. Positively charged amine-terminated pristine PEI, partially (50%) acetylated PEI (PEI-Ac50), and completely acetylated PEI (PEI-Ac) are able to improve PCR efficiency and specificity with an optimum concentration order of PEI < PEI-Ac50 < PEI-Ac, whereas negatively charged carboxyl-terminated PEI (PEI-SAH; SAH denotes succinamic acid groups) and neutralized PEI modified with both polyethylene glycol (PEG) and acetyl (Ac) groups (PEI-PEG-Ac) are unable to improve PCR specificity and efficiency even at concentrations three orders of magnitude higher than that of PEI. Our data clearly suggests that the PCR-enhancing effect is primarily based on the interaction between the PCR components and the PEI derivatives, where electrostatic interaction plays a major role in concentrating the PCR components locally on the backbones of the branched PEI. In addition, multiwalled carbon nanotubes modified with PEI and PEI-stabilized gold nanoparticles are also able to improve the PCR specificity and efficiency with an optimum PEI concentration less than that of the PEI alone, indicating that the inorganic component of the nanocomposites may help improve the interaction between PEI and the PCR components. The developed PEI-based derivatives or nanocomposites may be used as efficient additives to enhance other PCR systems for different biomedical applications. PMID:22393296

  3. Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

    NASA Astrophysics Data System (ADS)

    Pham, Huong T.; Maccarone, Alan T.; Campbell, J. Larry; Mitchell, Todd W.; Blanksby, Stephen J.

    2013-02-01

    Ozone-induced dissociation (OzID) is an alternative ion activation method that relies on the gas phase ion-molecule reaction between a mass-selected target ion and ozone in an ion trap mass spectrometer. Herein, we evaluated the performance of OzID for both the structural elucidation and selective detection of conjugated carbon-carbon double bond motifs within lipids. The relative reactivity trends for [M + X]+ ions (where X = Li, Na, K) formed via electrospray ionization (ESI) of conjugated versus nonconjugated fatty acid methyl esters (FAMEs) were examined using two different OzID-enabled linear ion-trap mass spectrometers. Compared with nonconjugated analogues, FAMEs derived from conjugated linoleic acids were found to react up to 200 times faster and to yield characteristic radical cations. The significantly enhanced reactivity of conjugated isomers means that OzID product ions can be observed without invoking a reaction delay in the experimental sequence (i.e., trapping of ions in the presence of ozone is not required). This possibility has been exploited to undertake neutral-loss scans on a triple quadrupole mass spectrometer targeting characteristic OzID transitions. Such analyses reveal the presence of conjugated double bonds in lipids extracted from selected foodstuffs. Finally, by benchmarking of the absolute ozone concentration inside the ion trap, second order rate constants for the gas phase reactions between unsaturated organic ions and ozone were obtained. These results demonstrate a significant influence of the adducting metal on reaction rate constants in the fashion Li > Na > K.

  4. Enhancement of selective decomposition. Adsorption and reaction of methanethiol on carbon-covered W(001)

    SciTech Connect

    Mullins, D.R.; Lyman, P.F.

    1995-04-13

    Selective decomposition of methanethiol (CH{sub 3}SH) on carbon-covered W(001) to produce methane is enhanced by 75% compared to the clean surface. The maximum enhancement requires only 0.25 monolayers (ML) of preadsorbed C. On a surface percovered with 0.8 ML of C, the methane desorbs in peaks at 460 and 550 K compared to 360 K on the clean surface, suggesting a greater stability in the C-S and C-H bonds. Increased intramolecular bond stability is confirmed by the temperature dependence of the S 2p and C 1s soft X-ray photoemission. Methyl thiolate, CH{sub 3}S, forms upon adsorption at 100 K. Chemisorbed methanethiol, which is not stable on the clean surface, is also observed between 100 and 300 K. The chemisorbed thiol decomposes to form additional thiolate. The thiolate reacts along three competing pathways. It undergoes rehydrogenation and desorbs as methanethiol, it selectively decomposes to form desorbed methane and adsorbed S, or it totally decomposes to form S, C, and desorbed H{sub 2}. 23 refs., 11 figs., 1 tab.

  5. A regenerative approach towards mucosal fenestration closure.

    PubMed

    Gandi, Padma; Anumala, Naveen; Reddy, Amarender; Chandra, Rampalli Viswa

    2013-06-06

    Mucosal fenestration is an opening or an interstice through the oral mucosa. A lesion which occurs with greater frequency than generally realised, its occurrence is attributed to a myriad of causes. Mucogingival procedures including connective tissue grafts, free gingival grafts and lateral pedicle grafts are generally considered to be the treatment of choice in the closure of a mucosal fenestration. More often, these procedures are performed in conjunction with other procedures such as periradicular surgery and with bone grafts. However, the concomitant use of gingival grafts and bone grafts in mucosal fenestrations secondary to infections in sites exhibiting severe bone loss is highly debatable. In this article, we report two cases of mucosal fenestrations secondary to trauma and their management by regenerative periodontal surgery with the placement of guided tissue regeneration membrane and bone graft. The final outcome was a complete closure of the fenestration in both the cases.

  6. A regenerative approach towards mucosal fenestration closure

    PubMed Central

    Gandi, Padma; Anumala, Naveen; Reddy, Amarender; Viswa Chandra, Rampalli

    2013-01-01

    Mucosal fenestration is an opening or an interstice through the oral mucosa. A lesion which occurs with greater frequency than generally realised, its occurrence is attributed to a myriad of causes. Mucogingival procedures including connective tissue grafts, free gingival grafts and lateral pedicle grafts are generally considered to be the treatment of choice in the closure of a mucosal fenestration. More often, these procedures are performed in conjunction with other procedures such as periradicular surgery and with bone grafts. However, the concomitant use of gingival grafts and bone grafts in mucosal fenestrations secondary to infections in sites exhibiting severe bone loss is highly debatable. In this article, we report two cases of mucosal fenestrations secondary to trauma and their management by regenerative periodontal surgery with the placement of guided tissue regeneration membrane and bone graft. The final outcome was a complete closure of the fenestration in both the cases. PMID:23749826

  7. Microbiota and mucosal immunity in amphibians.

    PubMed

    Colombo, Bruno M; Scalvenzi, Thibault; Benlamara, Sarah; Pollet, Nicolas

    2015-01-01

    We know that animals live in a world dominated by bacteria. In the last 20 years, we have learned that microbes are essential regulators of mucosal immunity. Bacteria, archeas, and viruses influence different aspects of mucosal development and function. Yet, the literature mainly covers findings obtained in mammals. In this review, we focus on two major themes that emerge from the comparative analysis of mammals and amphibians. These themes concern: (i) the structure and functions of lymphoid organs and immune cells in amphibians, with a focus on the gut mucosal immune system; and (ii) the characteristics of the amphibian microbiota and its influence on mucosal immunity. Lastly, we propose to use Xenopus tadpoles as an alternative small-animal model to improve the fundamental knowledge on immunological functions of gut microbiota.

  8. Topical therapy for mucosal yeast infections.

    PubMed

    Summers, Paul R

    2011-01-01

    Mucosal yeast infection is best understood as a consequence of compromised mucosal cell-mediated and innate immunity. Defense against oral candidiasis is dominantly cell mediated. The innate immune system may play the main role in regulating vulvovaginal yeast infection. Conditions that compromise cell-mediated immunity such as leukemia, severe illness and HIV infection must be considered as predisposing factors for recurrent oral candidiasis. Compromise of vaginal innate immunity due to mucosal allergy or due to a genetic defect such as mannose-binding lectin deficiency contributes to chronic vulvovaginal yeast infection. Treatment of cofactors must be considered in order to achieve control in recurrent mucosal yeast infection. Copyright © 2011 S. Karger AG, Basel.

  9. Targeting Mucosal Healing in Crohn's Disease

    PubMed Central

    Kakkar, Aarti; Wasan, Sharmeel K.

    2011-01-01

    The goal of medical treatment for Crohn's disease includes improving patients' quality of life while reducing the need for hospitalization and surgery. The current medical armamentarium includes 5-aminosalicylates, corticosteroids, immunomodulators, and biologic agents. In the past, response to treatment was measured by clinical improvement in symptoms; however, with the advent of disease-modifying medications, mucosal healing has emerged as an increasingly important goal of therapy. Mucosal healing, or endoscopic remission, is associated with increased rates of clinical remission, fewer hospitalizations, and fewer abdominal surgeries. Both the immunomodulator and biologic classes of medications are effective at inducing mucosal healing. Despite several limitations, mucosal healing has become a desirable and valid measure of disease activity. PMID:21869869

  10. Transgenic killer commensal bacteria as mucosal protectants.

    PubMed

    Polonelli, L

    2001-05-01

    As first line of defense against the majority of infections and primary site for their transmission, mucosal surfaces of the oral cavity and genitourinary, gastrointestinal, and respiratory tracts represent the most suitable sites to deliver protective agents for the prevention of infectious diseases. Mucosal protection is important not only for life threatening diseases but also for opportunistic infections which currently represent a serious burden in terms of morbidity, mortality, and cost of cures. Candida albicans is among the most prevalent causes of mucosal infections not only in immuno-compromised patients, such as HIV-infected subjects who are frequently affected by oral and esophageal candidiasis, but also in otherwise healthy individuals, as in the case of acute vaginitis. Unfortunately, current strategies for mucosal protection against candidiasis are severely limited by the lack of effective vaccines and the relative paucity and toxicity of commercially available antifungal drugs.

  11. Microbiota and Mucosal Immunity in Amphibians

    PubMed Central

    Colombo, Bruno M.; Scalvenzi, Thibault; Benlamara, Sarah; Pollet, Nicolas

    2015-01-01

    We know that animals live in a world dominated by bacteria. In the last 20 years, we have learned that microbes are essential regulators of mucosal immunity. Bacteria, archeas, and viruses influence different aspects of mucosal development and function. Yet, the literature mainly covers findings obtained in mammals. In this review, we focus on two major themes that emerge from the comparative analysis of mammals and amphibians. These themes concern: (i) the structure and functions of lymphoid organs and immune cells in amphibians, with a focus on the gut mucosal immune system; and (ii) the characteristics of the amphibian microbiota and its influence on mucosal immunity. Lastly, we propose to use Xenopus tadpoles as an alternative small-animal model to improve the fundamental knowledge on immunological functions of gut microbiota. PMID:25821449

  12. Mucosal Vaccination against Tuberculosis Using Inert Bioparticles

    PubMed Central

    Reljic, Rajko; Sibley, Laura; Huang, Jen-Min; Pepponi, Ilaria; Hoppe, Andreas; Hong, Huynh A.

    2013-01-01

    Needle-free, mucosal immunization is a highly desirable strategy for vaccination against many pathogens, especially those entering through the respiratory mucosa, such as Mycobacterium tuberculosis. Unfortunately, mucosal vaccination against tuberculosis (TB) is impeded by a lack of suitable adjuvants and/or delivery platforms that could induce a protective immune response in humans. Here, we report on a novel biotechnological approach for mucosal vaccination against TB that overcomes some of the current limitations. This is achieved by coating protective TB antigens onto the surface of inert bacterial spores, which are then delivered to the respiratory tract. Our data showed that mice immunized nasally with coated spores developed humoral and cellular immune responses and multifunctional T cells and, most importantly, presented significantly reduced bacterial loads in their lungs and spleens following pathogenic challenge. We conclude that this new vaccine delivery platform merits further development as a mucosal vaccine for TB and possibly also other respiratory pathogens. PMID:23959722

  13. Enhanced sensitivity of laterl flow strip biosensors based on enyzmatic reaction and nanomaterials

    NASA Astrophysics Data System (ADS)

    Xu, Hui

    Ultrasensitive detection for trace amount of proteins plays pivotal role in the diagnosis of specific diseases in clinical application, basic discovery research and the improvement of proteomics. Recently, lateral flow strip biosensor (LFSB) has gained considerable attention for protein analysis. Compared with the traditional immunoassays, LFSB has several advantages: user-friendly format, short assay time (generally several minutes), less interference due to chromatographic separation, a relatively low cost, and no requirements for skilled technicians. This ideal technique is suitable for on-site testing by people who are untrained. Traditional gold nanoparticles (GNPs) based LFSB have been used for qualitative and semiquantitative analysis, the application of GNP-based LFSB is limited by its low sensitivity. In this dissertation, different nanomaterials and advanced detection technologies have been used to enhance the LFSB sensitivities. An ultrasensitive LFSB based on horseradish peroxidase (HRP)/GNP dual labels was developed for qualitative (Yes/No) and quantitative detection of protein. The LFSB signal was enhanced dramatically by introducing the second tracer (enzyme) on the GNP surface. The detection limit of LFSB was 100 times lower than that of GNP-based LFSB. A fluorescent LFSB based on enzyme tracers was developed for sensitive detection of proteins. Alkaline Phosphatase (ALP) was selected as a label to prepare the LFSB. The signal was from the fluorescent emission of the ELF-97 alcohol precipitate which was the product of ALP catalyzed dephosphorylation of ELF-97 phosphate. ALP-conjugated antibody (ALP-Ab) functionalized gold nanoparticles (GNPs) were used as labels for the development of a chemiluminescence-based quantitative LFSB. The use of chemiluminescence detection and GNPs as enzyme carriers allowed accurate and sensitive analyte detection. GNP-decorated silica nanorods (GNP-SiNRs) were synthesized and employed as the labels for ultrasensitive

  14. Polyamines and Gut Mucosal Homeostasis

    PubMed Central

    Timmons, Jennifer; Chang, Elizabeth T.; Wang, Jian-Ying; Rao, Jaladanki N.

    2012-01-01

    The epithelium of gastrointestinal (GI) mucosa has the most rapid turnover rate of any tissue in the body and its integrity is preserved through the dynamic balance between cell migration, proliferation, growth arrest and apoptosis. To maintain tissue homeostasis of the GI mucosa, the rates of epithelial cell division and apoptosis must be highly regulated by various extracellular and intracellular factors including cellular polyamines. Natural polyamines spermidine, spermine and their precursor putrescine, are organic cations in eukaryotic cells and are implicated in the control of multiple signaling pathways and distinct cellular functions. Normal intestinal epithelial growth depends on the available supply of polyamines to the dividing cells in the crypts, and polyamines also regulate intestinal epithelial cell (IEC) apoptosis. Although the specific molecular processes controlled by polyamines remains to be fully defined, increasing evidence indicates that polyamines regulate intestinal epithelial integrity by modulating the expression of various growth-related genes. In this review, we will extrapolate the current state of scientific knowledge regarding the roles of polyamines in gut mucosal homeostasis and highlight progress in cellular and molecular mechanisms of polyamines and their potential clinical applications. PMID:25237589

  15. Electric Field-Enhanced Catalytic Conversion of Methane: AN Experimental Study on the Effects of Corona Discharge on Methane Reactions

    NASA Astrophysics Data System (ADS)

    Marafee, Abdulathim M. J.

    The oxidative coupling of methane (OCM) is currently being actively studied for the production of higher hydrocarbons from natural gas. The present study concentrates on the oxidative conversion of methane in a high-pressure (one atmosphere), nonthermal plasma formed by corona discharge. Here, methyl radicals are formed by the reaction of methane with negatively-charged oxygen species created in the corona discharge. The results of methane conversion in the presence of both AC and DC corona discharges revealed that ethane and ethylene product selectivity is affected by electrode polarity, frequency, and oxygen partial pressure in the feed. Higher C_2 yields were obtained with the AC corona. All of the AC corona discharges specified here were initiated at room temperature (i.e., no oven or other heat source used), with temperature increases from 300 to 500^circC due to the exothermic gas discharge and exothermic reaction. A reaction mechanism is presented to explain the observed phenomena. The results suggest that AC and/or DC gas discharge techniques should be further studied for improved economics of methane conversion. The oxidative dehydrogenation of ethane in DC corona discharges was investigated. The atomic oxygen radicals initiated by corona discharges are thought to be active for the OXD of ethane. The selectivity to ethylene is affected by the reaction temperature, the DC applied voltage, voltage polarity, and the C_2H _6/O_2 ratio. The results of this study suggest the corona discharge process to be very efficient and selective in the oxidative dehydrogenation of ethane. The effects of DC corona discharge were examined in the presence of a typical OCM catalyst, Sr/La _2O_3. Experimental investigations have correspondingly been conducted, in which all reactive gases passed through a catalyst bed situated within the corona-induced plasma zone. The methane conversion and C_2 yield increased (with O_2 partial pressure) during the corona-enhanced catalytic

  16. Three-dimensional ordered mesoporous Co3O4 enhanced by Pd for oxygen evolution reaction

    NASA Astrophysics Data System (ADS)

    Qu, Qing; Zhang, Jian-Hua; Wang, Jing; Li, Qing-Yu; Xu, Chang-Wei; Lu, Xihong

    2017-01-01

    Considerable efforts have been devoted recently to design and fabrication of high performance and low cost electrocatalysts for oxygen evolution reaction (OER). However, catalytic activity of current electrocatalysts is usually restricted by high onset potential and limited active sites. Herein, we fabricated three-dimensional (3D) highly ordered mesoporous Pd-Co3O4 composite materials as excellent electrocatalysts for OER in alkaline solution with high activity and stability. Three-dimensional highly ordered mesoporous Co3O4 material was firstly synthesized using mesoporous silica KIT-6 as hard template. Then, Pd-Co3O4 nanomaterials were prepared by a simple reduction method. The as-prepared 3D mesoporous Pd-Co3O4 catalysts have ordered mesoporous structure with a high surface area of 81.0 m2 g‑1. Three-dimensional highly ordered mesoporous structure can facilitate diffusion and penetration of electrolyte and oxygen. Moreover, the catalysts can also keep catalyst particles in a well dispersed condition with more catalytic active sites. Electrochemical measurements reveal that the 3D mesoporous Pd-Co3O4 catalysts exhibit superior performance in alkaline solution with low onset potential (0.415 V vs. SCE) and excellent long-duration cycling stability.

  17. Triggering comprehensive enhancement in oxygen evolution reaction by using newly created solvent

    PubMed Central

    Chen, Hsiao-Chien; Mai, Fu-Der; Yang, Kuang-Hsuan; Chen, Liang-Yih; Yang, Chih-Ping; Liu, Yu-Chuan

    2016-01-01

    Theoretical calculations indicate that the properties of confined liquid water, or liquid water at surfaces, are dramatically different from those of liquid bulk water. Here we present an experimentally innovative strategy on comprehensively efficient oxygen evolution reaction (OER) utilizing plasmon-induced activated water, creating from hot electron decay at resonantly illuminated Au nanoparticles (NPs). Compared to conventional deionized (DI) water, the created water owns intrinsically reduced hydrogen-bonded structure and a higher chemical potential. The created water takes an advantage in OER because the corresponding activation energy can be effectively reduced by itself. Compared to DI water-based solutions, the OER efficiencies at Pt electrodes increased by 69.3%, 21.1% and 14.5% in created water-based acidic, neutral and alkaline electrolyte solutions, respectively. The created water was also effective for OERs in photoelectrochemically catalytic and in inert systems. In addition, the efficiency of OER increased by 47.5% in created water-based alkaline electrolyte solution prepared in situ on a roughened Au electrode. These results suggest that the created water has emerged as an innovative activator in comprehensively effective OERs. PMID:27328821

  18. Enhancement of the Hydrogen Evolution Reaction from Ni-MoS2 Hybrid Nanoclusters

    PubMed Central

    2016-01-01

    This report focuses on a novel strategy for the preparation of transition metal–MoS2 hybrid nanoclusters based on a one-step, dual-target magnetron sputtering, and gas condensation process demonstrated for Ni-MoS2. Aberration-corrected STEM images coupled with EDX analysis confirms the presence of Ni and MoS2 in the hybrid nanoclusters (average diameter = 5.0 nm, Mo:S ratio = 1:1.8 ± 0.1). The Ni-MoS2 nanoclusters display a 100 mV shift in the hydrogen evolution reaction (HER) onset potential and an almost 3-fold increase in exchange current density compared with the undoped MoS2 nanoclusters, the latter effect in agreement with reported DFT calculations. This activity is only reached after air exposure of the Ni-MoS2 hybrid nanoclusters, suggested by XPS measurements to originate from a Ni dopant atoms oxidation state conversion from metallic to 2+ characteristic of the NiO species active to the HER. Anodic stripping voltammetry (ASV) experiments on the Ni-MoS2 hybrid nanoclusters confirm the presence of Ni-doped edge sites and reveal distinctive electrochemical features associated with both doped Mo-edge and doped S-edge sites which correlate with both their thermodynamic stability and relative abundance. PMID:27818842

  19. Triggering comprehensive enhancement in oxygen evolution reaction by using newly created solvent.

    PubMed

    Chen, Hsiao-Chien; Mai, Fu-Der; Yang, Kuang-Hsuan; Chen, Liang-Yih; Yang, Chih-Ping; Liu, Yu-Chuan

    2016-06-22

    Theoretical calculations indicate that the properties of confined liquid water, or liquid water at surfaces, are dramatically different from those of liquid bulk water. Here we present an experimentally innovative strategy on comprehensively efficient oxygen evolution reaction (OER) utilizing plasmon-induced activated water, creating from hot electron decay at resonantly illuminated Au nanoparticles (NPs). Compared to conventional deionized (DI) water, the created water owns intrinsically reduced hydrogen-bonded structure and a higher chemical potential. The created water takes an advantage in OER because the corresponding activation energy can be effectively reduced by itself. Compared to DI water-based solutions, the OER efficiencies at Pt electrodes increased by 69.3%, 21.1% and 14.5% in created water-based acidic, neutral and alkaline electrolyte solutions, respectively. The created water was also effective for OERs in photoelectrochemically catalytic and in inert systems. In addition, the efficiency of OER increased by 47.5% in created water-based alkaline electrolyte solution prepared in situ on a roughened Au electrode. These results suggest that the created water has emerged as an innovative activator in comprehensively effective OERs.

  20. Unilateral balance training enhances neuromuscular reactions to perturbations in the trained and contralateral limb.

    PubMed

    Oliveira, Anderson Souza Castelo; Brito Silva, Priscila; Farina, Dario; Kersting, Uwe Gustav

    2013-09-01

    The aim of this study was to investigate the effect of unilateral balance training on the reactive recovery of balance for both trained and untrained limbs. Twenty-three subjects were randomly assigned to either a control group (CG) or a training group (TG). The latter performed six weeks of balance training for the right leg. The pre- and post-training measurements were based on single leg standing posture on a moveable force platform which moved 6 cm anteriorly. TG subjects were tested on the trained (TR) and untrained leg (UTR), whereas CG subjects were tested on the right leg (CTR). The center of pressure trajectory length (CPLEN) and average speed (CPSPD) as well as onsets of muscular activation and time to peak (EMGTP) from lower limb muscles were calculated and compared by a 2-way ANOVA (three legs×two training status). Muscular onsets were reduced after training for TR (∼19 ms, p<0.05) and UTR (∼17 ms, p<0.05) with no significant changes for CTR. No effects of training for CPLEN and medial-lateral CPSPD were found. Furthermore, the EMGTP of UTR was predominantly greater before training (∼17 ms, p<0.05). However, after training the EMGTP was similar among limbs. These results suggest that concomitant with improved balance recovery and neuromuscular reactions in TR, there is also a cross-education effect in UTR, which might be predominantly related to supraspinal adaptations shared between interconnected structures in the brain.

  1. Biostability enhancement of oil core - polysaccharide multilayer shell via photoinitiator free thiol-ene 'click' reaction.

    PubMed

    Calcagno, Vincenzo; Vecchione, Raffaele; Sagliano, Angela; Carella, Antonio; Guarnieri, Daniela; Belli, Valentina; Raiola, Luca; Roviello, Antonio; Netti, Paolo A

    2016-06-01

    Layer-by-layer of polyelectrolytes has emerged as one of the easiest and most controlled techniques to deposit ultrathin polymer layers mainly driven by electrostatic interactions. However, this kind of interaction results to be weak and easily breakable in physiological environment. Here we report on the preparation of nanocapsules completely made of natural biomaterials: a lipophilic core (soybean oil and egg lecithin as surfactant) as nanometric template and a polysaccharide-based multilayer shell (glycol chitosan and heparin) covalently cross-linked. We first modified glycol chitosan with a thiol moiety and heparin with an alkene moiety, respectively, and then we built a polymer multilayer film with a covalent cross-linkage among layers, exploiting the light initiated thiol-ene reaction, known as click chemistry. We showed the possibility to perform the covalent cross-linkage without any photoinitiator or metal catalyst, thus avoiding cytotoxic effects and further purification steps. The so realized nanocapsules resulted to be stable and completely biocompatible and, therefore, of interest for the biotechnology fields, mainly for drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Three-dimensional ordered mesoporous Co3O4 enhanced by Pd for oxygen evolution reaction

    PubMed Central

    Qu, Qing; Zhang, Jian-Hua; Wang, Jing; Li, Qing-Yu; Xu, Chang-Wei; Lu, Xihong

    2017-01-01

    Considerable efforts have been devoted recently to design and fabrication of high performance and low cost electrocatalysts for oxygen evolution reaction (OER). However, catalytic activity of current electrocatalysts is usually restricted by high onset potential and limited active sites. Herein, we fabricated three-dimensional (3D) highly ordered mesoporous Pd-Co3O4 composite materials as excellent electrocatalysts for OER in alkaline solution with high activity and stability. Three-dimensional highly ordered mesoporous Co3O4 material was firstly synthesized using mesoporous silica KIT-6 as hard template. Then, Pd-Co3O4 nanomaterials were prepared by a simple reduction method. The as-prepared 3D mesoporous Pd-Co3O4 catalysts have ordered mesoporous structure with a high surface area of 81.0 m2 g−1. Three-dimensional highly ordered mesoporous structure can facilitate diffusion and penetration of electrolyte and oxygen. Moreover, the catalysts can also keep catalyst particles in a well dispersed condition with more catalytic active sites. Electrochemical measurements reveal that the 3D mesoporous Pd-Co3O4 catalysts exhibit superior performance in alkaline solution with low onset potential (0.415 V vs. SCE) and excellent long-duration cycling stability. PMID:28134348

  3. Predicting the Folding Pathway of Engrailed Homeodomain with a Probabilistic Roadmap Enhanced Reaction-Path Algorithm☆

    PubMed Central

    Li, Da-wei; Yang, Haijun; Han, Li; Huo, Shuanghong

    2008-01-01

    To predict a protein-folding pathway, we present an alternative to the time-consuming dynamic simulation of atomistic models. We replace the actual dynamic simulation with variational optimization of a reaction path connecting known initial and final protein conformations in such a way as to maximize an estimate of the reactive flux or minimize the mean first passage time at a given temperature, referred to as MaxFlux. We solve the MaxFlux global optimization problem with an efficient graph-theoretic approach, the probabilistic roadmap method (PRM). We employed CHARMM19 and the EEF1 implicit solvation model to describe the protein solution. The effectiveness of our MaxFlux-PRM is demonstrated in our promising simulation results on the folding pathway of the engrailed homeodomain. Our MaxFlux-PRM approach provides the direct evidence to support that the previously reported intermediate state is a genuine on-pathway intermediate, and the demand of CPU power is moderate. PMID:18024496

  4. α-1 Antitrypsin Enhances Islet Engraftment by Suppression of Instant Blood-Mediated Inflammatory Reaction.

    PubMed

    Wang, Jingjing; Sun, Zhen; Gou, Wenyu; Adams, David B; Cui, Wanxing; Morgan, Katherine A; Strange, Charlie; Wang, Hongjun

    2017-04-01

    Islet cell transplantation has limited effectiveness because of an instant blood-mediated inflammatory reaction (IBMIR) that occurs immediately after cell infusion and leads to dramatic β-cell death. In intraportal islet transplantation models using mouse and human islets, we demonstrated that α-1 antitrypsin (AAT; Prolastin-C), a serine protease inhibitor used for the treatment of AAT deficiency, inhibits IBMIR and cytokine-induced inflammation in islets. In mice, more diabetic recipients reached normoglycemia after intraportal islet transplantation when they were treated with AAT compared with mice treated with saline. AAT suppressed blood-mediated coagulation pathways by diminishing tissue factor production, reducing plasma thrombin-antithrombin complex levels and fibrinogen deposition on islet grafts, which correlated with less graft damage and apoptosis. AAT-treated mice showed reduced serum tumor necrosis factor-α levels, decreased lymphocytic infiltration, and decreased nuclear factor (NF)-κB activation compared with controls. The potent anti-inflammatory effect of AAT is possibly mediated by suppression of c-Jun N-terminal kinase (JNK) phosphorylation. Blocking JNK activation failed to further reduce cytokine-induced apoptosis in β-cells. Taken together, AAT significantly improves islet graft survival after intraportal islet transplantation by mitigation of coagulation in IBMIR and suppression of cytokine-induced JNK and NF-κB activation. AAT-based therapy has the potential to improve graft survival in human islet transplantation and other cellular therapies on the horizon.

  5. High Electrocatalytic Response of a Mechanically Enhanced NbC Nanocomposite Electrode Toward Hydrogen Evolution Reaction.

    PubMed

    Coy, Emerson; Yate, Luis; Valencia, Drochss P; Aperador, Willian; Siuzdak, Katarzyna; Torruella, Pau; Azanza, Eduardo; Estrade, Sonia; Iatsunskyi, Igor; Peiro, Francesca; Zhang, Xixiang; Tejada, Javier; Ziolo, Ronald F

    2017-09-13

    Resistant and efficient electrocatalysts for hydrogen evolution reaction (HER) are desired to replace scarce and commercially expensive platinum electrodes. Thin-film electrodes of metal carbides are a promising alternative due to their reduced price and similar catalytic properties. However, most of the studied structures neglect long-lasting chemical and structural stability, focusing only on electrochemical efficiency. Herein we report on a new approach to easily deposit and control the micro/nanostructure of thin-film electrodes based on niobium carbide (NbC) and their electrocatalytic response. We will show that, by improving the mechanical properties of the NbC electrodes, microstructure and mechanical resilience can be obtained while maintaining high electrocatalytic response. We also address the influence of other parameters such as conductivity and chemical composition on the overall performance of the thin-film electrodes. Finally, we show that nanocomposite NbC electrodes are promising candidates toward HER and, furthermore, that the methodology presented here is suitable to produce other transition-metal carbides with improved catalytic and mechanical properties.

  6. Cancer therapy-related oral mucositis.

    PubMed

    Redding, Spencer W

    2005-08-01

    Oral mucositis is a common side effect of cancer therapies, particularly radiation therapy for head and neck cancer and various forms of chemotherapy. It commonly results in severe oral pain that can compromise the duration and success of cancer management. Hospitalizations are common because patients lose the ability to take anything by mouth due to severe pain and must have alimentation supported during this period. Pain management usually requires potent narcotic analgesia. Cancer therapy-related oral mucositis is commonly described as the most significant and debilitating acute complication associated with radiation therapy and chemotherapy. Until recently, cancer therapy-induced oral mucositis was thought to be a process involving the epithelium only. Evidence is building that the process of oral mucositis involves far more than just the epithelium, but includes multiple cellular processes of the submucosa as well. Many strategies have been evaluated to prevent oral mucositis, but the data is confusing since it is often conflicting. Therapy with the growth factor, KGF1, appears promising, as it is the only medication currently approved by the FDA. A multifaceted approach that targets the entire mucositis process will probably be needed to optimize overall prevention.

  7. Simultaneous synthesis of gold nanoparticle/graphene nanocomposite for enhanced oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Govindhan, Maduraiveeran; Chen, Aicheng

    2015-01-01

    We report here on a novel and facile technique for the simultaneous synthesis of a highly active and stable gold (Au) nanoparticle/reduced graphene oxide (rGO) sheet nanocomposite as an efficient electrocatalyst to facilitate the oxygen reduction reaction (ORR). X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy and electrochemical methods were employed to characterize the Au and rGO nanocomposites formed on the electrode surface. The major advantage of the simultaneous synthetic method is the integration of the superb properties of both Au nanoparticles and graphene in a single-step with a 100% usage of the precursors. The Au/rGO nanocomposites exhibited pronounced electrocatalytic performance towards ORR with approximately three times higher than that of Au nanoparticles. The nanocomposites show the ORR onset peak potentials at 0.12 and -0.03 V (vs Ag/AgCl), with reduction peaks at -0.06 and -0.16 V (vs Ag/AgCl) in 0.1 M H2SO4 and KOH media, which is ∼120-190 mV more positive than that of Au nanoparticles and a commercial Pt/C catalyst. Moreover, the nanocomposites exhibit excellent methanol tolerance and high durability in comparison with the commercial Pt/C. The new method demonstrated in this study provides an efficient route for the generation of ultrafine and highly dense Au nanoparticles that are homogeneously dispersed on rGO sheets for ORR.

  8. Nanostructured silver for applications in surface enhanced Raman spectroscopy and photoelectrochemical reactions

    NASA Astrophysics Data System (ADS)

    Clayton, Daniel A.

    Initial work focused on characterizing silver and its surface enhanced Raman spectroscopy (SERS) capabilities. Silver nanowires were chosen as an ideal material and scanning confocal microscopy studies were performed to identify hot spots. The silver nanowires were found to exhibit fluorescence blinking that was attributed to small silver clusters undergoing rapid interchange from Ag0 to Ag2O. Control of this blinking was accomplished through the removal of oxygen and through electrochemical control of the system. SERS was also recorded from these nanowires. Deconvolution of the SERS signal from the fluorescence was accomplished either by increasing the SERS analyte concentration or increasing the total number of "hot spots" in the focus volume. Silver applications were studied by performing a SERS study of Rhodamine 6G (R6G) and Poly(3-hexylthiophene-2,5-diyl) (P3HT). A Tollens' silver substrate was utilized as the SERS substrate and similar blinking effects were found to arise. P3HT was cast from 4 different solvents:dichloromethane, chlorobenzene, THF, and toluene. The solvent effects were studied, with kinking of the polymer noted in the non-chlorinated solvents. Single molecule studies in conjunction with polarization control indicated that the P3HT formed in an overlapping manner with only partial charge transfer within the molecule. Finally silvers interactions with TiO2 were studied. Micron scale single crystal anatase TiO2 was synthesized by using HF in a hydrothermal process forming a truncated bipyramidal structure consisting of [101] and [001] faces. Fluorine was present in small amounts on the surface of the TiO2 as confirmed by x-ray photoelectron spectroscopy (XPS). An annealing process was used to remove the fluorine. Nitrogen doping was attempted, but was not found to occur in significant amounts. Visible light sensitivity was noted in annealed samples but did not occur in the bulk as demonstrated through photoelectrochemical measurements. Silver

  9. Enhanced formic acid electro-oxidation reaction on ternary Pd-Ir-Cu/C catalyst

    NASA Astrophysics Data System (ADS)

    Chen, Jinwei; Zhang, Jie; Jiang, Yiwu; Yang, Liu; Zhong, Jing; Wang, Gang; Wang, Ruilin

    2015-12-01

    Aim to further reduce the cost of Pd-Ir for formic acid electro-oxidation (FAEO), the Cu was used to construct a ternary metallic alloy catalyst. The prepared catalysts are characterized using XRD, TGA, EDX, TEM, XPS, CO-stripping, cyclic voltammetry and chronoamperometry. It is found that the Pd18Ir1Cu6 nanoparticles with a mean size of 3.3 nm are highly dispersed on carbon support. Componential distributions on catalyst are consistent with initial contents. Electrochemical measurements show that the PdIrCu/C catalyst exhibits the highest activity for FAEO. The mass activity of Pd in Pd18Ir1Cu6/C at 0.16 V (vs. SCE) is about 1.47, 1.62 and 2.08 times as high as that of Pd18Cu6/C, Pd18Ir1/C and Pd/C, respectively. The activity enhancement of PdIrCu/C should be attributed to the weakened CO adsorption strength and the removal of adsorbed intermediates at lower potential with the addition of Cu and Ir.

  10. Enhanced ethanol electro-oxidation reaction on carbon supported Pd-metal oxide electrocatalysts.

    PubMed

    Abdel Hameed, R M

    2017-11-01

    Various Pd-metal oxide/C electrocatalysts were fabricated using ethylene glycol as a reducing agent in modified microwave-assisted polyol process. The crystal structure and surface morphology were studied using X-ray diffraction and transmission electron microscopy. All prepared Pd-metal oxide/C electrocatalysts exhibited a shift of Pd diffraction planes in the positive direction in relation to that of Pd/C. Highly dispersed palladium nanoparticles were formed on different metal oxide/C supports. The electrocatalytic performance of these electrocatalysts for ethanol oxidation was examined in NaOH solution using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. An improvement in electrochemical parameters including onset potential, oxidation current density and If/Ib values was recorded at different Pd-metal oxide/C electrocatalysts, especially Pd-NiO/C. Three folds increment in steady state oxidation current density value was also displayed by investigated Pd-metal oxide/C electrocatalysts when contrasted to that of Pd/C to reflect their enhanced stability behavior. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Enhancing the specificity of the enterokinase cleavage reaction to promote efficient cleavage of a fusion tag.

    PubMed

    Shahravan, S Hesam; Qu, Xuanlu; Chan, I-San; Shin, Jumi A

    2008-06-01

    In our work with designed minimalist proteins based on the bZIP motif, we have found our His-tagged proteins to be prone to inclusion body formation and aggregation; we suspect this problem is largely due to the His tag, known to promote aggregation. Using AhR6-C/EBP, a hybrid of the AhR basic region and C/EBP leucine zipper, as representative of our bZIP-like protein family, we attempted removal of the His tag with enterokinase (EK) but obtained the desired cleavage product in very small yield. EK is known for proteolysis at noncanonical sites, and most cleavage occurred at unintended sites. We manipulated experimental conditions to improve specificity of proteolysis and analyzed the cleavage products; no effect was observed after changing pH, temperature, or the amount of EK. We then suspected the accessibility of the EK site was impeded due to protein aggregation. We found that the easily implemented strategy of addition of urea (1-4 M) greatly improved EK cleavage specificity at the canonical site and reduced adventitious cleavage. We believe that this enhancement in specificity is due to a more "open" protein structure, in which the now accessible canonical target can compete effectively with adventitious cleavage sites of related sequence.

  12. Increased Mucosal CD4+ T Cell Activation in Rhesus Macaques following Vaccination with an Adenoviral Vector

    PubMed Central

    Bukh, Irene; Calcedo, Roberto; Roy, Soumitra; Carnathan, Diane G.; Grant, Rebecca; Qin, Qiuyue; Boyd, Surina; Ratcliffe, Sarah J.; Veeder, Christin L.; Bellamy, Scarlett L.; Betts, Michael R.

    2014-01-01

    ABSTRACT The possibility that vaccination with adenovirus (AdV) vectors increased mucosal T cell activation remains a central hypothesis to explain the potential enhancement of HIV acquisition within the Step trial. Modeling this within rhesus macaques is complicated because human adenoviruses, including human adenovirus type 5 (HAdV-5), are not endogenous to macaques. Here, we tested whether vaccination with a rhesus macaque-derived adenoviral vector (simian adenovirus 7 [SAdV-7]) enhances mucosal T cell activation within rhesus macaques. Following intramuscular SAdV-7 vaccination, we observed a pronounced increase in SAdV-7-specific CD4+ T cell responses in peripheral blood and, more dramatically, in rectal mucosa tissue. Vaccination also induced a significant increase in the frequency of activated memory CD4+ T cells in SAdV-7- and HAdV-5-vaccinated animals in the rectal mucosa but not in peripheral blood. These fluctuations within the rectal mucosa were also associated with a pronounced decrease in the relative frequency of naive resting CD4+ T cells. Together, these results indicate that peripheral vaccination with an AdV vector can increase the activation of mucosal CD4+ T cells, potentially providing an experimental model to further evaluate the role of host-vector interactions in increased HIV acquisition after AdV vector vaccination. IMPORTANCE The possibility that vaccination with a human adenovirus 5 vector increased mucosal T cell activation remains a central hypothesis to explain the potential enhancement of human immunodeficiency virus (HIV) acquisition within the Step trial. In this study, we tested whether vaccination with a rhesus macaque-derived adenoviral vector in rhesus macaques enhances mucosal CD4+ T cell activation, the main cell target of simian immunodeficiency virus (SIV)/HIV. The results showed that vaccination with an adenoviral vector indeed increases activation of mucosal CD4+ T cells and potentially increases susceptibility to SIV

  13. Ultrathin Coating of Confined Pt Nanocatalysts by Atomic Layer Deposition for Enhanced Catalytic Performance in Hydrogenation Reactions.

    PubMed

    Wang, Meihua; Gao, Zhe; Zhang, Bin; Yang, Huimin; Qiao, Yan; Chen, Shuai; Ge, Huibin; Zhang, Jiankang; Qin, Yong

    2016-06-13

    Metal-support interfaces play a prominent role in heterogeneous catalysis. However, tailoring the metal-support interfaces to realize full utilization remains a major challenge. In this work, we propose a graceful strategy to maximize the metal-oxide interfaces by coating confined nanoparticles with an ultrathin oxide layer. This is achieved by sequential deposition of ultrathin Al2 O3 coats, Pt, and a thick Al2 O3 layer on carbon nanocoils templates by atomic layer deposition (ALD), followed by removal of the templates. Compared with the Pt catalysts confined in Al2 O3 nanotubes without the ultrathin coats, the ultrathin coated samples have larger Pt-Al2 O3 interfaces. The maximized interfaces significantly improve the activity and the protecting Al2 O3 nanotubes retain the stability for hydrogenation reactions of 4-nitrophenol. We believe that applying ALD ultrathin coats on confined catalysts is a promising way to achieve enhanced performance for other catalysts.

  14. Pore-scale mechanisms for the enhancement of mixing in unsaturated porous media and implications for chemical reactions

    NASA Astrophysics Data System (ADS)

    Jiménez-Martínez, Joaquín.; Anna, Pietro de; Tabuteau, Hervé; Turuban, Régis; Borgne, Tanguy Le; Méheust, Yves

    2015-07-01

    Porous media in which different fluid phases coexist are common in nature (e.g., vadose zone and gas-oil reservoirs). In partially saturated porous media, the intricate spatial distributions of the wetting and nonwetting phases causes their flow to be focused onto preferential paths. Using a novel 2-D experimental setup allowing pore-scale measurement of concentration fields in a controlled unsaturated flow, we highlight mechanisms by which mixing of an invading fluid with the resident fluid is significantly enhanced when decreasing saturation. The mean scalar dissipation rate is observed to decrease slowly in time, while under saturated conditions it decays rapidly. This slow decrease is due to sustained longitudinal solute fingering, which causes concentration gradients to remain predominantly transverse to the average flow. Consequently, the effective reactivity is found to be much larger than under saturated conditions. These results provide new insights into the role that multiphase flows play on mixing/reaction in porous media.

  15. Novel molybdenum disulfide nanosheets-decorated polyaniline: Preparation, characterization and enhanced electrocatalytic activity for hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Ding, Shuangshuang; He, Ping; Feng, Wanru; Li, Lian; Zhang, Guangli; Chen, Jingchao; Dong, Faqin; He, Huichao

    2016-04-01

    Novel molybdenum disulfide nanosheets-decorated polyaniline (MoS2/PANI) was synthesized and investigated as an efficient catalyst for hydrogen evolution reaction (HER). Compared with MoS2, MoS2/PANI nanocomposites exhibited higher catalytic activity and lower Tafel slope for HER in H2SO4 solution. The amount of 19 wt% PANI for coupling with MoS2 resulted in a high current density of 80 mA cm-2 at 400 mV (vs. RHE). In addition, the optimal MoS2/PANI nanocomposite showed impressive long-term stability even after 500 cycles. The enhanced catalytic activity of MoS2/PANI nanocomposites was primarily ascribed to the effective electron transport channels of PANI and the increase of electrochemically accessible surface area in composite materials, which was advantageous to facilitate the charge transfer at catalyst/electrolyte interface.

  16. Palladium networks decorated by cuprous oxide for remarkably enhanced electrocatalytic activity of methanol oxidation reaction with high CO-tolerance

    NASA Astrophysics Data System (ADS)

    Ji, Yuanyuan; Ying, Ye; Pan, Yuxia; Li, Mengzhu; Guo, Xiaoyu; Wu, Yiping; Wen, Ying; Yang, Haifeng

    2016-10-01

    The CuO nanorods (NRs) are prepared with the help of inositol hexakisphosphate which serves as a binding agent and stabilizer. We have successfully fabricated Cu2O-decorated palladium networks (Cu2O/Pd Networks) by using such CuO NRs as reaction beds. Transmission electron microscopy images show that Cu2O/Pd network is composed of small and irregular fused nanoparticles with an average size of about 10 nm. Electrochemical results depict that the as-synthesized catalyst exhibits 2-fold higher activity for methanol oxidation than the commercially available 20% Pd/C catalyst and Pd black catalyst. Furthermore, CO-tolerance is also remarkably enhanced due to the presence of Cu2O. Such highly active, low-cost, and superiorly CO-tolerant catalysts of Cu2O/Pd Networks will open up a new avenue for direct methanol fuel cells.

  17. Electrochemical fabrication of platinum nanoflakes on fulleropyrrolidine nanosheets and their enhanced electrocatalytic activity and stability for methanol oxidation reaction

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Ma, Li-Xia

    2015-07-01

    Pyridine-functionalized fulleropyrrolidine nanosheets are prepared by a fast reprecipitation method under ultrasonication, and used as a novel nanostructured support materials to fabricate Pt catalyst nanoflakes by a simple electrodeposition approach. The as-prepared novel Pt-fullerene hybrid catalyst (Pt/PyC60) exhibits much enhanced electrocatalytic activity and stability for methanol oxidation reaction compared to the unsupported Pt nanoflakes and commercial Pt/C. The introduction of nanostructured fulleropyrrolidine as new support materials not only increases the electrochemically active surface area of catalyst, but also significantly improves the long-term stability. This will contribute to developing functionalized fullerenes as new nanostructured support materials for advanced electrocatalysts in fuel cells.

  18. Synergistic effect of laminin and mesenchymal stem cells on tracheal mucosal regeneration.

    PubMed

    Lee, Doh Young; Lee, Jin Ho; Ahn, Hee-Jin; Oh, Se Heang; Kim, Tae Ho; Kim, Hee-Bok; Park, Seok-Won; Kwon, Seong Keun

    2015-03-01

    Although several studies have been successfully undertaken of tracheal reconstruction in terms of the maintaining the framework of the graft, most cases of reconstruction failure have resulted from delayed mucosal regeneration. The purposes of this study were to evaluate whether laminin-coated asymmetrically porous membrane (APM) scaffold enhances mucosal regeneration, to compare the mucosalization capability with mesenchymal stem cell (MSC) seeded APM, and to determine whether laminin coating and MSC seeding has a synergistic effect on mucosal regeneration. We reconstructed the full-thickness anterior tracheal defect of 36 New Zealand White rabbits with the APM scaffold. MSCs were isolated from the rabbit's inguinal fat. The animals were divided into 4 groups by the presence of laminin coating on APM and application of MSC [Group I, -/- (laminin/MSC); Group II, -/+; Group III, +/-; Group IV, +/+]. Endoscopy and histologic evaluation were performed and the results were compared among the groups. The results showed that ciliated columnar epithelium was regenerated earlier in groups II and III than in group I. Furthermore, the application of laminin and MSC had synergistic effects on tracheal epithelial regeneration. These results demonstrate that tracheal reconstruction by laminin-coated APM seeded with MSCs is most effective in enhancing tracheal mucosalization, and appears to be promising strategy in the regenerative treatment of tracheal defects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Coral kin aggregations exhibit mixed allogeneic reactions and enhanced fitness during early ontogeny.

    PubMed

    Amar, Keren-Or; Chadwick, Nanette E; Rinkevich, Baruch

    2008-04-30

    Aggregated settlement of kin larvae in sessile marine invertebrates may result in a complex array of compatible and incompatible allogeneic responses within each assemblage. Each such aggregate can, therefore, be considered as a distinct self-organizing biological entity representing adaptations that have evolved to maximize the potential benefits of gregarious settlement. However, only sparse information exists on the selective forces and ecological consequences of allogeneic coalescence. We studied the consequences of aggregated settlement of kin larvae of Stylophora pistillata (a Red Sea stony coral), under controlled laboratory settings. When spat came into contact, they either fused, establishing a chimera, or rejected one another. A one-year study on growth and survivorship of 544 settled S. pistillata genotypes revealed six types of biological entities: (1) Single genotypes (SG); (2) Bi-chimeras (BC); (3) Bi-rejecting genotypes (BR); (4) Tri-chimera entities (TC); (5) Three-rejecting genotypes (TR); and (6) Multi-partner entities (MP; consisting of 7.5 +/- 2.6 partners). Analysis of allorecognition responses revealed an array of effector mechanisms: real tissue fusions, transitory fusions and six other histoincompatible reactions (borderline formation, sutures, overgrowth, bleaching, rejection, and partner death), disclosing unalike onsets of ontogeny and complex modes of appearance within each aggregate. Evaluations at the entity level revealed that MP entities were the largest, especially in the first two months (compared with SG: 571% in the first month and 162% in the seventh month). However, at the genotype level, the SG entities were the largest and the colonies with the highest-cost-per-genotype were the TR and the MP colonies. The cost was calculated as reduced average genotype size, from 27% and 12% in the first month to 67% and 64% in the seventh month, respectively. In general, MP exhibited the highest survivorship rate (85%, after one year) and

  20. Coral kin aggregations exhibit mixed allogeneic reactions and enhanced fitness during early ontogeny

    PubMed Central

    2008-01-01

    Background Aggregated settlement of kin larvae in sessile marine invertebrates may result in a complex array of compatible and incompatible allogeneic responses within each assemblage. Each such aggregate can, therefore, be considered as a distinct self-organizing biological entity representing adaptations that have evolved to maximize the potential benefits of gregarious settlement. However, only sparse information exists on the selective forces and ecological consequences of allogeneic coalescence. Results We studied the consequences of aggregated settlement of kin larvae of Stylophora pistillata (a Red Sea stony coral), under controlled laboratory settings. When spat came into contact, they either fused, establishing a chimera, or rejected one another. A one-year study on growth and survivorship of 544 settled S. pistillata genotypes revealed six types of biological entities: (1) Single genotypes (SG); (2) Bi-chimeras (BC); (3) Bi-rejecting genotypes (BR); (4) Tri-chimera entities (TC); (5) Three-rejecting genotypes (TR); and (6) Multi-partner entities (MP; consisting of 7.5 ± 2.6 partners). Analysis of allorecognition responses revealed an array of effector mechanisms: real tissue fusions, transitory fusions and six other histoincompatible reactions (borderline formation, sutures, overgrowth, bleaching, rejection, and partner death), disclosing unalike onsets of ontogeny and complex modes of appearance within each aggregate. Evaluations at the entity level revealed that MP entities were the largest, especially in the first two months (compared with SG: 571% in the first month and 162% in the seventh month). However, at the genotype level, the SG entities were the largest and the colonies with the highest-cost-per-genotype were the TR and the MP colonies. The cost was calculated as reduced average genotype size, from 27% and 12% in the first month to 67% and 64% in the seventh month, respectively. In general, MP exhibited the highest survivorship rate (85

  1. On the reaction of D-amino acid oxidase with dioxygen: O2 diffusion pathways and enhancement of reactivity.

    PubMed

    Rosini, Elena; Molla, Gianluca; Ghisla, Sandro; Pollegioni, Loredano

    2011-02-01

    Evidence is accumulating that oxygen access in proteins is guided and controlled. We also have recently described channels that might allow access of oxygen to pockets at the active site of the flavoprotein D-amino acid oxidase (DAAO) that have a high affinity for dioxygen and are in close proximity to the flavin. With the goal of enhancing the reactivity of DAAO with oxygen, we have performed site-saturation mutagenesis at three positions that flank the putative oxygen channels and high-affinity sites. The most interesting variants at positions 50, 201 and 225 were identified by a screening procedure at low oxygen concentration. The biochemical properties of these variants have been studied and compared with those of wild-type DAAO, with emphasis on the reactivity of the reduced enzyme species with dioxygen. The substitutions at positions 50 and 225 do not enhance this reaction, but mainly affect the protein conformation and stability. However, the T201L variant shows an up to a threefold increase in the rate constant for reaction of O(2) with reduced flavin, together with a fivefold decrease in the K(m) for dioxygen. This effect was not observed when a valine is located at position 201, and is thus attributed to a specific alteration in the micro-environment of one high-affinity site for dioxygen (site B) close to the flavin that plays an important role in the storage of oxygen. The increase in O(2) reactivity observed for T201L DAAO is of great interest for designing new flavoenzymes for biotechnological applications.

  2. Enhancement of visual scoring of skin irritant reactions using cross-polarized light and parallel-polarized light.

    PubMed

    Farage, Miranda A

    2008-03-01

    Polarized light has been used as an aid in visualizing various skin conditions, including acne vulgaris, rosacea, photoageing, lentigo simplex, and basal cell carcinoma. The use of parallel-polarized and cross-polarized light was evaluated in mild irritant reactions to determine, if this increases the ability to detect very early stages or low levels of irritation. Low concentrations of sodium lauryl sulfate (0.01% and 0.1%) were patched on human volunteers for 2, 6, and 24 hr, daily for 2-3 days in a modification of the standard patch test. Feminine protection products were evaluated in the behind-the-knee (BTK) test. Erythema reactions were scored by unaided visual assessment and using a polarized light visualization system. In the 24-hr patch test, mean erythema assessed with polarized light was consistent with results of unaided visual scoring. Under milder conditions (2- and 6-hr patches), and in the BTK, significant differences from pretreatment levels of erythema were apparent earlier in the series of treatments compared with unaided scoring. In addition, subsurface scoring demonstrated that changes were still present under the skin surface even after unaided visual scoring indicated recovery. Low (subclinical) levels of irritation can be detected using enhanced visual scoring, indicating this non-invasive method has the potential to increase the sensitivity of our clinical studies.

  3. Enhanced autotrophic astaxanthin production from Haematococcus pluvialis under high temperature via heat stress-driven Haber-Weiss reaction.

    PubMed

    Hong, Min-Eui; Hwang, Sung Kwan; Chang, Won Seok; Kim, Byung Woo; Lee, Jeewon; Sim, Sang Jun

    2015-06-01

    High temperatures (30-36 °C) inhibited astaxanthin accumulation in Haematococcus pluvialis under photoautotrophic conditions. The depression of carotenogenesis was primarily attributed to excess intracellular less reactive oxygen species (LROS; O2 (-) and H2O2) levels generated under high temperature conditions. Here, we show that the heat stress-driven inefficient astaxanthin production was improved by accelerating the iron-catalyzed Haber-Weiss reaction to convert LROS into more reactive oxygen species (MROS; O2 and OH·), thereby facilitating lipid peroxidation. As a result, during 18 days of photoautotrophic induction, the astaxanthin concentration of cells cultured in high temperatures in the presence of iron (450 μM) was dramatically increased by 75 % (30 °C) and 133 % (36 °C) compared to that of cells exposed to heat stress alone. The heat stress-driven Haber-Weiss reaction will be useful for economically producing astaxanthin by reducing energy cost and enhancing photoautotrophic astaxanthin production, particularly outdoors utilizing natural solar radiation including heat and light for photo-induction of H. pluvialis.

  4. Humin as an electron donor for enhancement of multiple microbial reduction reactions with different redox potentials in a consortium.

    PubMed

    Zhang, Dongdong; Zhang, Chunfang; Xiao, Zhixing; Suzuki, Daisuke; Katayama, Arata

    2015-02-01

    A solid-phase humin, acting as an electron donor, was able to enhance multiple reductive biotransformations, including dechlorination of pentachlorophenol (PCP), dissimilatory reduction of amorphous Fe (III) oxide (FeOOH), and reduction of nitrate, in a consortium. Humin that was chemically reduced by NaBH4 served as an electron donor for these microbial reducing reactions, with electron donating capacities of 0.013 mmol e(-)/g for PCP dechlorination, 0.15 mmol e(-)/g for iron reduction, and 0.30 mmol e(-)/g for nitrate reduction. Two pairs of oxidation and reduction peaks within the humin were detected by cyclic voltammetry analysis. 16S rRNA gene sequencing-based microbial community analysis of the consortium incubated with different terminal electron acceptors, suggested that Dehalobacter sp., Bacteroides sp., and Sulfurospirillum sp. were involved in the PCP dechlorination, dissimilatory iron reduction, and nitrate reduction, respectively. These findings suggested that humin functioned as a versatile redox mediator, donating electrons for multiple respiration reactions with different redox potentials. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Understanding the role of gold nanoparticles in enhancing the catalytic activity of manganese oxides in water oxidation reactions.

    PubMed

    Kuo, Chung-Hao; Li, Weikun; Pahalagedara, Lakshitha; El-Sawy, Abdelhamid M; Kriz, David; Genz, Nina; Guild, Curtis; Ressler, Thorsten; Suib, Steven L; He, Jie

    2015-02-16

    The Earth-abundant and inexpensive manganese oxides (MnOx) have emerged as an intriguing type of catalysts for the water oxidation reaction. However, the overall turnover frequencies of MnOx catalysts are still much lower than that of nanostructured IrO2 and RuO2 catalysts. Herein, we demonstrate that doping MnOx polymorphs with gold nanoparticles (AuNPs) can result in a strong enhancement of catalytic activity for the water oxidation reaction. It is observed that, for the first time, the catalytic activity of MnOx/AuNPs catalysts correlates strongly with the initial valence of the Mn centers. By promoting the formation of Mn(3+) species, a small amount of AuNPs (<5%) in α-MnO2/AuNP catalysts significantly improved the catalytic activity up to 8.2 times in the photochemical and 6 times in the electrochemical system, compared with the activity of pure α-MnO2.

  6. Monitoring the inorganic chemical reaction by surface-enhanced Raman spectroscopy: A case of Fe³⁺ to Fe²⁺ conversion.

    PubMed

    Qin, Suhua; Meng, Juan; Tang, Xianghu; Yang, Liangbao

    2016-01-01

    Monitoring the process of organic chemical reactions to study the kinetics by surface-enhanced Raman spectroscopy (SERS) is currently of immense interest. However, monitoring the inorganic chemical reaction is still an extremely difficulty for researchers. This study exactly focused on the monitor of inorganic chemical reaction. Capillary coated with silver nanoparticles was introduced, which was an efficient platform for monitoring reactions with SERS due to the advantages of sensitivity and excellent reproducibility. The photoreduction of [Fe(phen)3](3+) to [Fe(phen)3](2+) was used as model reaction to demonstrated the feasibility of SERS monitoring inorganic chemical reaction by involving in metal-organic complexes. Moreover, the preliminary implementation demonstrated that the kinetics of photoreduction can be real-time monitored by in situ using the SERS technique on a single constructed capillary, which may be useful for the practical application of SERS technique. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Reactivation of Mucosal and Cutaneous Leishmaniasis in a Renal Transplanted Patient

    PubMed Central

    Tuon, Felipe F.; Bombonatto, Giovana Marina; Battaglin, Eveline Roesler; Sakumoto, Marcus Henrique; Amato, Valdir Sabbaga; de Camargo, Raphael Abegão; Nicodemo, Antônio Carlos

    2014-01-01

    Mucosal leishmaniasis (ML) is a chronic form of tegumentary leishmaniasis, which causes destructive lesions of nasal, pharyngeal, and laryngeal mucosa. We describe a case of leishmaniasis reactivation with simultaneous cutaneous and mucosal forms in a renal transplanted patient with no history of prior leishmaniasis. Reactivation after renal transplantation was not reported in Brazil. A 67-year-old woman receiving prednisone 20 mg/day, tacrolimus 1 mg/day, and mycophenolic acid 360 mg/day presented with nose edema with erythema and cutaneous lesions. Amastigotes were identified on biopsies and the polymerase chain reaction confirmed Leishmania (Viannia) braziliensis. The patient was treated with liposomal amphotericin B but died 3 weeks after as a result of bacterial septic shock. In conclusion, tegumentary leishmaniasis can reactivate with simultaneous cutaneous and mucosal forms in a renal transplanted patient during the immunosuppressant therapy. PMID:24732458

  8. Vacuum Ultraviolet and Ultraviolet Radiation-Induced Effect of Hydrogenated Silicon Nitride Etching: Surface Reaction Enhancement and Damage Generation

    NASA Astrophysics Data System (ADS)

    Fukasawa, Masanaga; Miyawaki, Yudai; Kondo, Yusuke; Takeda, Keigo; Kondo, Hiroki; Ishikawa, Kenji; Sekine, Makoto; Matsugai, Hiroyasu; Honda, Takayoshi; Minami, Masaki; Uesawa, Fumikatsu; Hori, Masaru; Tatsumi, Tetsuya

    2012-02-01

    Photon-enhanced etching of SiNx:H films caused by the interaction between vacuum ultraviolet (VUV)/ultraviolet (UV) radiation and radicals in the fluorocarbon plasma was investigated by a technique with a novel sample setup of the pallet for plasma evaluation. The simultaneous injection of UV radiation and radicals causes a dramatic etch rate enhancement of SiNx:H films. Only UV radiation causes the film shrinkage of SiNx:H films owing to hydrogen desorption from the film. Capacitance-voltage characteristics of SiNx:H/Si substrates were studied before and after UV radiation. The interface trap density increased monotonically upon irradiating the UV photons with a wavelength of 248 nm. The estimated effective interface trap generation probability is 4.74 ×10-7 eV-1·photon-1. Therefore, the monitoring of the VUV/UV spectra during plasma processing and the understanding of its impact on the surface reaction, film damage and electrical performance of underlying devices are indispensable to fabricate advanced devices.

  9. The reactions of NO2/N2O4 with Ag: A surface enhanced Raman scattering and ellipsometric measurement

    NASA Astrophysics Data System (ADS)

    Dorain, Paul B.; Boggio, Joseph E.

    1986-01-01

    This paper, to our knowledge, reports the first detailed kinetic study of surface chemical reactions on Ag metal powder using surface enhanced Raman scattering (SERS). A pulse technique was used to admit NO2/N2O4 gas to the Ag powder surface in the temperature range of 20-80 °C. The initial chemical step is the formation of AgNO2 which subsequently decomposes autocatalytically into AgNO3, NO, and Ag. It is the product Ag metal atoms which aggregate, forming the Ag microstructures necessary for the SERS enhancement mechanisms to be operative. Ellipsometric and scanning electron microscope measurements confirm the existence of the Ag microstructures which are embedded in the AgNO3 surface film. Subsequent pulses of NO2/N2O4 rapidly react with the Ag microstructures which suggests that the process may be used to study in situ heterogeneous catalysis of other gases on Ag metal surfaces at ambient and elevated temperatures.

  10. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions

    NASA Astrophysics Data System (ADS)

    Shen, Cenchao; Yang, Wenjuan; Ji, Qiaoli; Maki, Hisaji; Dong, Anjie; Zhang, Zhizhou

    2009-11-01

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  11. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions.

    PubMed

    Shen, Cenchao; Yang, Wenjuan; Ji, Qiaoli; Maki, Hisaji; Dong, Anjie; Zhang, Zhizhou

    2009-11-11

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  12. Differences in microbial signatures between rectal mucosal biopsies and rectal swabs.

    PubMed

    Araújo-Pérez, Félix; McCoy, Amber N; Okechukwu, Charles; Carroll, Ian M; Smith, Kevin M; Jeremiah, Kim; Sandler, Robert S; Asher, Gary N; Keku, Temitope O

    2012-01-01

    There is growing evidence the microbiota of the large bowel may influence the risk of developing colorectal cancer as well as other diseases including type-1 diabetes, inflammatory bowel diseases and irritable bowel syndrome. Current sampling methods to obtain microbial specimens, such as feces and mucosal biopsies, are inconvenient and unappealing to patients. Obtaining samples through rectal swabs could prove to be a quicker and relatively easier method, but it is unclear if swabs are an adequate substitute. We compared bacterial diversity and composition from rectal swabs and rectal mucosal biopsies in order to examine the viability of rectal swabs as an alternative to biopsies. Paired rectal swabs and mucosal biopsy samples were collected in un-prepped participants (n = 11) and microbial diversity was characterized by Terminal Restriction Fragment Length polymorphism (T-RFLP) analysis and quantitative polymerase chain reaction (qPCR) of the 16S rRNA gene. Microbial community composition from swab samples was different from rectal mucosal biopsies (p = 0.001). Overall the bacterial diversity was higher in swab samples than in biopsies as assessed by diversity indexes such as: richness (p = 0.01), evenness (p = 0.06) and Shannon's diversity (p = 0.04). Analysis of specific bacterial groups by qPCR showed higher copy number of Lactobacillus (p < 0.0001) and Eubacteria (p = 0.0003) in swab samples compared with biopsies. Our findings suggest that rectal swabs and rectal mucosal samples provide different views of the microbiota in the large intestine.

  13. Bone marrow transplantation helps restore the intestinal mucosal barrier after total body irradiation in mice.

    PubMed

    Garg, Sarita; Wang, Wenze; Prabath, Biju G; Boerma, Marjan; Wang, Junru; Zhou, Daohong; Hauer-Jensen, Martin

    2014-03-01

    Bone marrow transplantation (BMT) substantially improves 10-day survival after total body irradiation (TBI), consistent with an effect on intestinal radiation death. Total body irradiation, in addition to injuring the intestinal epithelium, also perturbs the mucosal immune system, the largest immune system in the body. This study focused on how transplanted bone marrow cells (BMCs) help restore mucosal immune cell populations after sublethal TBI (8.0 Gy). We further evaluated whether transplanted BMCs: (a) home to sites of radiation injury using green fluorescent protein labeled bone marrow; and (b) contribute to restoring the mucosal barrier in vivo. As expected, BMT accelerated recovery of peripheral blood (PB) cells. In the intestine, BMT was associated with significant early recovery of mucosal granulocytes (P = 0.005). Bone marrow transplantation did not affect mucosal macrophages or lymphocyte populations at early time points, but enhanced the recovery of these cells from day 14 onward (P = 0.03). Bone marrow transplantation also attenuated radiation-induced increase of intestinal CXCL1 and restored IL-10 levels (P = 0.001). Most importantly, BMT inhibited the post-radiation increase in intestinal permeability after 10 Gy TBI (P = 0.02) and modulated the expression of tight junction proteins (P = 0.01-0.05). Green fluorescent protein-positive leukocytes were observed both in intestinal tissue and in PB. These findings strongly suggest that BMT, in addition to enhancing general hematopoietic and immune system recovery, helps restore the intestinal immune system and enhances intestinal mucosal barrier function. These findings may be important in the development and understanding of strategies to alleviate or treat intestinal radiation toxicity.

  14. Anti-ulcerogenic effect of banana powder (Musa sapientum var. paradisiaca) and its effect on mucosal resistance.

    PubMed

    Goel, R K; Gupta, S; Shankar, R; Sanyal, A K

    1986-10-01

    Orally administered banana pulp powder (Musa sapientum var. paradisiaca) was shown to have significant anti-ulcerogenic activity in rats subjected to aspirin, indomethacin, phenylbutazone, prednisolone and cysteamine and in guinea-pigs subjected to histamine. Banana powder not only increased mucosal thickness but also significantly increased [3H]thymidine incorporation into mucosal DNA. Relative to untreated control sections, histological studies showed that banana treatment increased staining by alcian blue in the apical cells with staining noted in the deeper layers of the mucosal glands. Banana-treated and control sections were also stained for DNA by the Feulgen reaction. The banana-treated sections showed a greater aggregation and intensity of pink spots when compared to controls. The present study suggests that banana powder treatment not only strengthens mucosal resistance against ulcerogens but also promotes healing by inducing cellular proliferation.

  15. Visceral and mucosal involvement in neonatal haemangiomatosis.

    PubMed

    Maruani, A; Piram, M; Sirinelli, D; Herbreteau, D; Saliba, E; Machet, M C; Lorette, G

    2012-10-01

    Two types of neonatal haemangiomatosis (NH) are distinguished: diffuse which is associated with a high rate of mortality linked to mucosal/visceral involvement, and benign. First, this study aimed to examine the frequency of mucosal and visceral (especially hepatic) involvement in NH, according to skin extension, and second, it aimed to examine clinical, pathological (with glucose transporter 1 (GLUT-1) immunostaining), and imaging features of NH, including follow-up data. This was a descriptive retrospective study carried out in the University Hospital Center of Tours, France. The study included 19 patients with cutaneous NH (number of skin haemangiomas ranging from 5 to >100). Mucosal involvement was observed in 32% of all cases (100% and 19% in diffuse and other cutaneous cases respectively) and hepatic involvement in 42% (67% and 38% respectively). The number of hepatic haemangiomas ranged from 1 to >10. Half of the hepatic haemangiomas cases exhibited increased hepatic arterial blood flow. Mucosal and hepatic involvement was frequent in cases with a high number of cutaneous haemangiomas (>100), but only frequency of mucosal involvement was statistically significant (P = 0.021). © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

  16. Enhancement by cigarette smoke extract of the radical formation in a reaction mixture of 13-hydroperoxide octadecadienoic acid and ferric ions.

    PubMed

    Iimura, Sae; Iwahashi, Hideo

    2006-04-01

    The effects of cigarette smoke extract on radical formation were examined in reaction mixtures containing 13-hydroperoxide octadecadienoic acid (13-HPODE), FeCl3, cigarette smoke extract, ethylenediaminetetraacetic acid (EDTA), alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN), and phosphate buffer (pH 7.4). Cigarette smoke extract enhanced the formation of both 7-carboxyheptyl and pentyl radicals in the reaction. Ferric ions were reduced in the reaction mixture, suggesting that cigarette smoke extract enhances the formation of 7-carboxyheptyl and pentyl radicals by reducing ferric irons. Although there is a large body of evidence supporting the involvement of radicals such as the semiquinone radical, hydroxyl radical, superoxide radical, nitric oxide radicals in smoking-related diseases, the enhancement by cigarette smoke of lipid-derived radical formation, which we first report here, may be one of the other causes of smoking-related diseases.

  17. An NK Cell Perforin Response Elicited via IL-18 Controls Mucosal Inflammation Kinetics during Salmonella Gut Infection

    PubMed Central

    Müller, Anna A.; Dolowschiak, Tamas; Sellin, Mikael E.; Felmy, Boas; Verbree, Carolin; Gadient, Sandra; Westermann, Alexander J.; Vogel, Jörg; LeibundGut-Landmann, Salome; Hardt, Wolf-Dietrich

    2016-01-01

    Salmonella Typhimurium (S.Tm) is a common cause of self-limiting diarrhea. The mucosal inflammation is thought to arise from a standoff between the pathogen's virulence factors and the host's mucosal innate immune defenses, particularly the mucosal NAIP/NLRC4 inflammasome. However, it had remained unclear how this switches the gut from homeostasis to inflammation. This was studied using the streptomycin mouse model. S.Tm infections in knockout mice, cytokine inhibition and –injection experiments revealed that caspase-1 (not -11) dependent IL-18 is pivotal for inducing acute inflammation. IL-18 boosted NK cell chemoattractants and enhanced the NK cells' migratory capacity, thus promoting mucosal accumulation of mature, activated NK cells. NK cell depletion and Prf-/- ablation (but not granulocyte-depletion or T-cell deficiency) delayed tissue inflammation. Our data suggest an NK cell perforin response as one limiting factor in mounting gut mucosal inflammation. Thus, IL-18-elicited NK cell perforin responses seem to be critical for coordinating mucosal inflammation during early infection, when S.Tm strongly relies on virulence factors detectable by the inflammasome. This may have broad relevance for mucosal defense against microbial pathogens. PMID:27341123

  18. An NK Cell Perforin Response Elicited via IL-18 Controls Mucosal Inflammation Kinetics during Salmonella Gut Infection.

    PubMed

    Müller, Anna A; Dolowschiak, Tamas; Sellin, Mikael E; Felmy, Boas; Verbree, Carolin; Gadient, Sandra; Westermann, Alexander J; Vogel, Jörg; LeibundGut-Landmann, Salome; Hardt, Wolf-Dietrich

    2016-06-01

    Salmonella Typhimurium (S.Tm) is a common cause of self-limiting diarrhea. The mucosal inflammation is thought to arise from a standoff between the pathogen's virulence factors and the host's mucosal innate immune defenses, particularly the mucosal NAIP/NLRC4 inflammasome. However, it had remained unclear how this switches the gut from homeostasis to inflammation. This was studied using the streptomycin mouse model. S.Tm infections in knockout mice, cytokine inhibition and -injection experiments revealed that caspase-1 (not -11) dependent IL-18 is pivotal for inducing acute inflammation. IL-18 boosted NK cell chemoattractants and enhanced the NK cells' migratory capacity, thus promoting mucosal accumulation of mature, activated NK cells. NK cell depletion and Prf-/- ablation (but not granulocyte-depletion or T-cell deficiency) delayed tissue inflammation. Our data suggest an NK cell perforin response as one limiting factor in mounting gut mucosal inflammation. Thus, IL-18-elicited NK cell perforin responses seem to be critical for coordinating mucosal inflammation during early infection, when S.Tm strongly relies on virulence factors detectable by the inflammasome. This may have broad relevance for mucosal defense against microbial pathogens.

  19. Prospective Evaluation to Establish a Dose Response for Clinical Oral Mucositis in Patients Undergoing Head-and-Neck Conformal Radiotherapy

    SciTech Connect

    Narayan, Samir Lehmann, Joerg; Coleman, Matthew A.; Vaughan, Andrew; Yang, Claus Chunli; Enepekides, Danny; Farwell, Gregory; Purdy, James A.; Laredo, Grace; Nolan, Kerry A.S.; Pearson, Francesca S.; Vijayakumar, Srinivasan

    2008-11-01

    Purpose: We conducted a clinical study to correlate oral cavity dose with clinical mucositis, perform in vivo dosimetry, and determine the feasibility of obtaining buccal mucosal cell samples in patients undergoing head-and-neck radiation therapy. The main objective is to establish a quantitative dose response for clinical oral mucositis. Methods and Materials: Twelve patients undergoing radiation therapy for head-and-neck cancer were prospectively studied. Four points were chosen in separate quadrants of the oral cavity. Calculated dose distributions were generated by using AcQPlan and Eclipse treatment planning systems. MOSFET dosimeters were used to measure dose at each sampled point. Each patient underwent buccal sampling for future RNA analysis before and after the first radiation treatment at the four selected points. Clinical and functional mucositis were assessed weekly according to National Cancer Institute Common Toxicity Criteria, Version 3. Results: Maximum and average doses for sampled sites ranged from 7.4-62.3 and 3.0-54.3 Gy, respectively. A cumulative point dose of 39.1 Gy resulted in mucositis for 3 weeks or longer. Mild severity (Grade {<=} 1) and short duration ({<=}1 week) of mucositis were found at cumulative point doses less than 32 Gy. Polymerase chain reaction consistently was able to detect basal levels of two known radiation responsive genes. Conclusions: In our sample, cumulative doses to the oral cavity of less than 32 Gy were associated with minimal acute mucositis. A dose greater than 39 Gy was associated with longer duration of mucositis. Our technique for sampling buccal mucosa yielded sufficient cells for RNA analysis using polymerase chain reaction.

  20. Connexins in respiratory and gastrointestinal mucosal immunity.

    PubMed

    Bou Saab, Joanna; Losa, Davide; Chanson, Marc; Ruez, Richard

    2014-04-17

    The mucosal lining forms the physical and chemical barrier that protects against pathogens and hostile particles and harbors its own population of bacteria, fungi and archea, known as the microbiota. The immune system controls tolerance of this population of microorganisms that have proven to be beneficial for its host. Keeping its physical integrity and a correct balance with the microbiota, the mucosa preserves its homeostasis and its protective function and maintains host's health. However, in some conditions, pathogens may succeed in breaching mucosal homeostasis and successfully infecting the host. In this review we will discuss the role the mucosa plays in the defense against bacterial pathogens by considering the gap junction protein connexins. We will detail their implication in mucosal homeostasis and upon infection with bacteria in the respiratory and the gastrointestinal tracts. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  1. Mucosal Immunity and Candida albicans Infection

    PubMed Central

    Moyes, David L.; Naglik, Julian R.

    2011-01-01

    Interactions between mucosal surfaces and microbial microbiota are key to host defense, health, and disease. These surfaces are exposed to high numbers of microbes and must be capable of distinguishing between those that are beneficial or avirulent and those that will invade and cause disease. Our understanding of the mechanisms involved in these discriminatory processes has recently begun to expand as new studies bring to light the importance of epithelial cells and novel immune cell subsets such as Th17 T cells in these processes. Elucidating how these mechanisms function will improve our understanding of many diverse diseases and improve our ability to treat patients suffering from these conditions. In our voyage to discover these mechanisms, mucosal interactions with opportunistic commensal organisms such as the fungus Candida albicans provide insights that are invaluable. Here, we review current knowledge of the interactions between C. albicans and epithelial surfaces and how this may shape our understanding of microbial-mucosal interactions. PMID:21776285

  2. C. albicans Colonization of Human Mucosal Surfaces

    PubMed Central

    Southern, Peter; Horbul, Julie; Maher, Diane; Davis, Dana A.

    2008-01-01

    Background Candida albicans is a low level commensal organism in normal human populations with the continuous potential to expand and cause a spectrum of clinical conditions. Methodology/Principal Findings Using ex vivo human organ cultures and populations of primary human cells, we have developed several related experimental systems to examine early-stage interactions between C. albicans and mucosal surfaces. Experiments have been conducted both with exogenously added C. albicans and with overtly normal human mucosal surfaces supporting pre-existing infections with natural isolates of Candida. Under different culture conditions, we have demonstrated the formation of C. albicans colonies on human target cells and filament formation, equivalent to tissue invasion. Conclusions/Significance These organ culture systems provide a valuable new resource to examine the molecular and cellular basis for Candida colonization of human mucosal surfaces. PMID:18446191

  3. Detection of deoxyribonucleic acid (DNA) targets using polymerase chain reaction (PCR) and paper surface-enhanced Raman spectroscopy (SERS) chromatography.

    PubMed

    Hoppmann, Eric P; Yu, Wei W; White, Ian M

    2014-01-01

    Surface-enhanced Raman spectroscopy (SERS) enables multiplex detection of analytes using simple, portable equipment consisting of a single excitation source and detector. Thus, in theory, SERS is ideally suited to replace fluorescence in assays that screen for numerous deoxyribonucleic acid (DNA) targets, but in practice, SERS-based assays have suffered from complexity and elaborate processing steps. Here, we report an assay in which a simple inkjet-fabricated plasmonic paper device enables SERS-based detection of multiple DNA targets within a single polymerase chain reaction (PCR). In prior work, we demonstrated the principles of chromatographic separation and SERS-based detection on inkjet-fabricated plasmonic paper. The present work extends that capability for post-PCR gene sequence detection. In this design, hydrolysis DNA probes with 5' Raman labels are utilized; if the target is present, the probe is hydrolyzed during PCR, freeing the reporter. After applying the PCR sample to a paper SERS device, an on-device chromatographic separation and concentration is conducted to discriminate between hydrolyzed and intact probes. SERS is then used to detect the reporter released by the hydrolyzed probes. This simple separation and detection on paper eliminates the need for complex sample processing steps. In this work, we simultaneously detect the methicillin-resistant Staphylococcus aureus genes mecA and femB to illustrate the concept. We envision that this approach could contribute to the development of multiplex DNA diagnostic tests enabling screening for several target sequences within a single reaction, which is necessary for cases in which sample volume and resources are limited.

  4. Bifunctional Ag@SiO 2 /Au Nanoparticles for Probing Sequential Catalytic Reactions by Surface-Enhanced Raman Spectroscopy

    DOE PAGES

    Wu, Yiren; Su, Dong; Qin, Dong

    2017-02-22

    Here, we report the synthesis of bifunctional Ag@SiO2/Au nanoparticles with an “islands in the sea” configuration by titrating HAuCl4 solution into an aqueous suspension of Ag@SiO2 core–shell nanocubes in the presence of NaOH, ascorbic acid, and poly(vinyl pyrrolidone) at pH 11.9. The NaOH plays an essential role in generating small pores in the SiO2 shell in situ, followed by the epitaxial deposition of Au from the Ag surface through the pores, leading to the formation of Au islands (6–12 nm in size) immersed in a SiO2 sea. Furthermore, by controlling the amount of HAuCl4 titrated into the reaction system, themore » Au islands can be made to pass through and protrude from the SiO2 shell, embracing catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. And while the Ag in the core provides a strong surface-enhanced Raman scattering activity, the SiO2 sea helps maintain the Au component as compact, isolated, and stabilized islands. The Ag@SiO2/Au nanoparticles can serve as a bifunctional probe to monitor the stepwise Au-catalyzed reduction of 4-nitrothiophenol to 4-aminothiophenol by NaBH4 and Ag-catalyzed oxidation of 4-aminothiophenol to trans-4,4'-dimercaptoazobenzene by the O2 from air in the same reaction system.« less

  5. Enhanced electrocatalytic activity of MoS(x) on TCNQ-treated electrode for hydrogen evolution reaction.

    PubMed

    Chang, Yung-Huang; Nikam, Revannath D; Lin, Cheng-Te; Huang, Jing-Kai; Tseng, Chien-Chih; Hsu, Chang-Lung; Cheng, Chia-Chin; Su, Ching-Yuan; Li, Lain-Jong; Chua, Daniel H C

    2014-10-22

    Molybdenum sulfide has recently attracted much attention because of its low cost and excellent catalytical effects in the application of hydrogen evolution reaction (HER). To improve the HER efficiency, many researchers have extensively explored various avenues such as material modification, forming hybrid structures or modifying geometric morphology. In this work, we reported a significant enhancement in the electrocatalytic activity of the MoSx via growing on Tetracyanoquinodimethane (TCNQ) treated carbon cloth, where the MoSx was synthesized by thermolysis from the ammonium tetrathiomolybdate ((NH4)2MoS4) precursor at 170 °C. The pyridinic N- and graphitic N-like species on the surface of carbon cloth arising from the TCNQ treatment facilitate the formation of Mo(5+) and S2(2-) species in the MoSx, especially with S2(2-) serving as an active site for HER. In addition, the smaller particle size of the MoSx grown on TCNQ-treated carbon cloth reveals a high ratio of edge sites relative to basal plane sites, indicating the richer effective reaction sites and superior electrocatalytic characteristics. Hence, we reported a high hydrogen evolution rate for MoSx on TCNQ-treated carbon cloth of 6408 mL g(-1) cm(-2) h(-1) (286 mmol g(-1) cm(-2) h(-1)) at an overpotential of V = 0.2 V. This study provides the fundamental concepts useful in the design and preparation of transition metal dichalcogenide catalysts, beneficial in the development in clean energy.

  6. Pulsed Laser-Assisted Focused Electron-Beam-Induced Etching of Titanium with XeF 2 : Enhanced Reaction Rate and Precursor Transport

    SciTech Connect

    Noh, J. H.; Fowlkes, J. D.; Timilsina, R.; Stanford, M. G.; Lewis, B. B.; Rack, P. D.

    2015-01-28

    We introduce a laser-assisted focused electron-beam-induced etching (LA-FEBIE) process which is a versatile, direct write nanofabrication method that allows nanoscale patterning and editing; we do this in order to enhance the etch rate of electron-beam-induced etching. The results demonstrate that the titanium electron stimulated etch rate via the XeF2 precursor can be enhanced up to a factor of 6 times with an intermittent pulsed laser assist. Moreover, the evolution of the etching process is correlated to in situ stage current measurements and scanning electron micrographs as a function of time. Finally, the increased etch rate is attributed to photothermally enhanced Ti–F reaction and TiF4 desorption and in some regimes enhanced XeF2 surface diffusion to the reaction zone.

  7. Pulsed laser-assisted focused electron-beam-induced etching of titanium with XeF2: enhanced reaction rate and precursor transport.

    PubMed

    Noh, J H; Fowlkes, J D; Timilsina, R; Stanford, M G; Lewis, B B; Rack, P D

    2015-02-25

    In order to enhance the etch rate of electron-beam-induced etching, we introduce a laser-assisted focused electron-beam-induced etching (LA-FEBIE) process which is a versatile, direct write nanofabrication method that allows nanoscale patterning and editing. The results demonstrate that the titanium electron stimulated etch rate via the XeF2 precursor can be enhanced up to a factor of 6 times with an intermittent pulsed laser assist. The evolution of the etching process is correlated to in situ stage current measurements and scanning electron micrographs as a function of time. The increased etch rate is attributed to photothermally enhanced Ti-F reaction and TiF4 desorption and in some regimes enhanced XeF2 surface diffusion to the reaction zone.

  8. Origin of Enhanced Reactivity of a Microsolvated Nucleophile in Ion Pair SN2 Reactions: The Cases of Sodium p-Nitrophenoxide with Halomethanes in Acetone.

    PubMed

    Li, Qiang-Gen; Xu, Ke; Ren, Yi

    2015-04-30

    In a kinetic experiment on the SN2 reaction of sodium p-nitrophenoxide with iodomethane in acetone-water mixed solvent, Humeres et al. (J. Org. Chem. 2001, 66, 1163) found that the reaction depends strongly on the medium, and the fastest rate constant was observed in pure acetone. The present work tries to explore why acetone can enhance the reactivity of the title reactions. Accordingly, we make a mechanistic study on the reactions of sodium p-nitrophenoxide with halomethanes (CH3X, X = Cl, Br, I) in acetone by using a supramolecular/continuum model at the PCM-MP2/6-311+G(d,p)//B3LYP/6-311+G(d,p) level, in which the ion pair nucleophile is microsolvated by one to three acetone molecules. We compared the reactivity of the microsolvated ion pair nucleophiles with solvent-free ion pair and anionic ones. Our results clearly reveal that the microsolvated ion pair nucleophile is favorable for the SN2 reactions; meanwhile, the origin of the enhanced reactivity induced by microsolvation of the nucleophile is discussed in terms of the geometries of transition state (TS) structures and activation strain model, suggesting that lower deformation energies and stronger interaction energies between the deformed reactants in the TS lead to the lower overall reaction barriers for the SN2 reaction of microsolvated sodium p-nitrophenoxide toward halomethanes in acetone.

  9. Non-surgical treatment of peri-implant mucositis and peri-implantitis: a literature review.

    PubMed

    Renvert, Stefan; Roos-Jansåker, Ann-Marie; Claffey, Noel

    2008-09-01

    To review the literature on non-surgical treatment of peri-implant mucositis and peri-implantitis. A search of PubMed and The Cochrane Library of the Cochrane Collaboration (CENTRAL) as well as a hand search of articles were conducted. Publications and articles accepted for publication up to November 2007 were included. Out of 437 studies retrieved a total of 24 studies were selected for the review. Thus the available evidence for non-surgical treatment of peri-implant mucositis and peri-implantitis is scarce. It was observed that mechanical non-surgical therapy could be effective in the treatment of peri-implant mucositis lesions. Furthermore, the adjunctive use of antimicrobial mouth rinses enhanced the outcome of mechanical therapy of such mucositis lesions. In peri-implantitis lesions non-surgical therapy was not found to be effective. Adjunctive chlorhexidine application had only limited effects on clinical and microbiological parameters. However, adjunctive local or systemic antibiotics were shown to reduce bleeding on probing and probing depths. Minor beneficial effects of laser therapy on peri-implantitis have been shown; this approach needs to be further evaluated. There is a need for randomized-controlled studies evaluating treatment models of non-surgical therapy of peri-implant mucositis and peri-implantitis.

  10. HIV enteropathy and aging: gastrointestinal immunity, mucosal epithelial barrier, and microbial translocation.

    PubMed

    Wang, Hongyin; Kotler, Donald P

    2014-07-01

    Despite decreases in morbidity and mortality as a result of antiretroviral therapy, gastrointestinal dysfunction remains common in HIV infection. Treated patients are at risk for complications of 'premature' aging, such as cardiovascular disease, osteopenia, neurocognitive decline, malignancies, and frailty. This review summarizes recent observations in this field. Mucosal CD4 lymphocytes, especially Th17 cells, are depleted in acute HIV and simian immune deficiency virus (SIV) infections, although other cell types also are affected. Reconstitution during therapy often is incomplete, especially in mucosa. Mucosal barrier function is affected by both HIV infection and aging and includes paracellular transport via tight junctions and uptake through areas of apoptosis; other factors may affect systemic antigen exposure. The resultant microbial translocation is associated with systemic immune activation in HIV and SIV infections. There is evidence of immune activation and microbial translocation in the elderly. The immune phenotypes of immunosenescence in HIV infection and aging appear similar. There are several targets for intervention; blockage of residual mucosal virus replication, preventing antigen uptake, modulating the microbiome, improving T cell recovery, combining therapies aimed at mucosal integrity, augmenting mucosal immunity, and managing traditional risk factors for premature aging in the general population. Aging may interact with HIV enteropathy to enhance microbial translocation and immune activation.

  11. Oral mucosal diseases: evaluation and management.

    PubMed

    Stoopler, Eric T; Sollecito, Thomas P

    2014-11-01

    Oral mucosal diseases encompass several common conditions that affect the general population. Some of these disorders present with signs and symptoms that are pathognomonic for the condition, whereas others present with similar features that can make clinical diagnosis difficult to achieve. It is important for physicians to have a clear understanding of these disorders to provide appropriate care to patients. This article reviews clinical aspects of common oral mucosal disorders, including candidiasis, herpes simplex viral infections, aphthous stomatitis, lichen planus, pemphigus vulgaris, and mucous membrane pemphigoid.

  12. Sub-4 nm PtZn Intermetallic Nanoparticles for Enhanced Mass and Specific Activities in Catalytic Electrooxidation Reaction

    DOE PAGES

    Qi, Zhiyuan; Xiao, Chaoxian; Liu, Cong; ...

    2017-03-08

    Atomically ordered intermetallic nanoparticles (iNPs) have sparked considerable interest in fuel cell applications by virtue of their exceptional electronic and structural properties. However, the synthesis of small iNPs in a controllable manner remains a formidable challenge because of the high temperature generally required in the formation of intermetallic phases. Here in this paper we report a general method for the synthesis of PtZn iNPs (3.2 ± 0.4 nm) on multiwalled carbon nanotubes (MWNT) via a facile and capping agent free strategy using a sacrificial mesoporous silica (mSiO2) shell. The as-prepared PtZn iNPs exhibited ca. 10 times higher mass activity inmore » both acidic and basic solution toward the methanol oxidation reaction (MOR) compared to larger PtZn iNPs synthesized on MWNT without the mSiO2 shell. Density functional theory (DFT) calculations predict that PtZn systems go through a “non-CO” pathway for MOR because of the stabilization of the OH* intermediate by Zn atoms, while a pure Pt system forms highly stable COH* and CO* intermediates, leading to catalyst deactivation. Experimental studies on the origin of the backward oxidation peak of MOR coincide well with DFT predictions. Moreover, the calculations demonstrate that MOR on smaller PtZn iNPs is energetically more favorable than larger iNPs, due to their high density of corner sites and lower-lying energetic pathway. Therefore, smaller PtZn iNPs not only increase the number but also enhance the activity of the active sites in MOR compared with larger ones. This work opens a new avenue for the synthesis of small iNPs with more undercoordinated and enhanced active sites for fuel cell applications.« less

  13. RT3D Reaction Modules for Natural and Enhanced Attenuation of Chloroethanes, Chloroethenes, Chloromethanes, and Daughter Products

    SciTech Connect

    Johnson, Christian D.; Truex, Michael J.

    2006-07-25

    This document describes a suite of MNA/EA reaction modules that were developed for addressing complex chlorinated solvent reactions using RT3D. As an introduction, an overview of these MNA/EA reaction modules is presented, including discussions of similarities between reaction modules, the purpose of key reaction parameters, and important considerations for using the reaction modules. Subsequent sections provide the details of the reaction kinetics (conceptual model and equations), data input requirements, and example (batch reactor) results for each reaction module. This document does not discuss reaction module implementation or validation; such information will accompany the software in the form of release notes or a supplement to the RT3D manual.

  14. Induction of mucosal and systemic antibody and T-cell responses following prime–boost immunization with novel adjuvanted human immunodeficiency virus-1-vaccine formulations

    PubMed Central

    Cristillo, Anthony D.; Ferrari, Maria Grazia; Hudacik, Lauren; Lewis, Brad; Galmin, Lindsey; Bowen, Britany; Thompson, DeVon; Petrovsky, Nikolai; Markham, Phillip; Pal, Ranajit

    2011-01-01

    As sexual transmission of human immunodeficiency virus-1 (HIV-1) occurs via the mucosa, an ideal HIV-1 vaccine should induce both mucosal and systemic immunity. We therefore sought to evaluate the induction of mucosal responses using a DNA env prime–gp120 protein boost approach in which sequential nasal and parenteral protein administration was performed with two novel carbohydrate-based adjuvants. These adjuvants, Advax-M and Advax-P, were specifically designed for mucosal and systemic immune enhancement, respectively. Murine intranasal immunization with gp120/Advax-M adjuvant elicited gp120-specific IgA in serum and mucosal secretions that was markedly enhanced by DNA priming. Boosting of DNA-primed mice with gp120/Advax-M and gp120/Advax-P by sequential intranasal and intramuscular immunization, or vice versa, elicited persistent mucosal gp120-specific IgA, systemic IgG and memory T- and B-cell responses. Induction of homologous, but not heterologous, neutralizing activity was noted in the sera of all immunized groups. While confirmation of efficacy is required in challenge studies using non-human primates, these results suggest that the combination of DNA priming with sequential nasal and parenteral protein boosting, with appropriate mucosal and systemic adjuvants, could generate strong mucosal and systemic immunity and may block HIV-1 mucosal transmission and infection. PMID:21169215

  15. Impact of Mucosal Inflammation on Oral Simian Immunodeficiency Virus Transmission

    PubMed Central

    Chen, Hui-Ling; Hodara, Vida L.; Chu, Lianrui; Parodi, Laura M.; Smith, Lisa M.; Sexton, Valerie; Cappelli, David; Sodora, Donald L.

    2013-01-01

    Mucosal tissues are the primary route of transmission for most respiratory and sexually transmitted diseases, including human immunodeficiency virus (HIV). There is epidemiological evidence that genital mucosal inflammation leads to enhanced HIV type 1 (HIV-1) transmission. The objective of this study was to assess the influence of periodontal inflammation on oral HIV transmission using a nonhuman primate model of teeth ligature-induced periodontitis. Simian immunodeficiency virus (SIV) was nontraumatically applied to the gingiva after moderate gingivitis was identified through clinical and immunologic analyses (presence of inflammatory cytokines). Overall oral SIV infection rates were similar in the gingivitis-induced and control groups (5 infections following 12 SIV administrations for each), although more macaques were infected with multiple viral variants in the gingivitis group. SIV infection also affected the levels of antiviral and inflammatory cytokines in the gingival crevicular fluid, and a synergistic effect was observed, with alpha interferon and interferon-inducible protein 10 undergoing significant elevations following SIV infection in macaques with gingivitis compared to controls. These increases in antiviral and inflammatory immune modulators in the SIV-infected gingivitis macaques could also be observed in blood plasma, although the effects at both compartments were generally restricted to the acute phase of the infection. In conclusion, while moderate gingivitis was not associated with increased susceptibility to oral SIV infection, it resulted in elevated levels of cytokines in the oral mucosa and plasma of the SIV-infected macaques. These findings suggest a synergy between mucosal inflammation and SIV infection, creating an immune milieu that impacts the early stages of the SIV infection with potential implications for long-term pathogenesis. PMID:23175379

  16. Suppression of gastric mucosal inflammatory responses to Helicobacter pylori lipopolysaccharide by sulglycotide.

    PubMed

    Slomiany, B L; Piotrowski, J; Slomiany, A

    1999-02-01

    The effect of the antiulcer agent sulglycotide on gastric epithelial cell apoptosis and the expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-4 (IL-4) during Helicobacter pylori lipopolysaccharide-induced acute gastritis was investigated. Rats, pretreated twice daily for 3 consecutive days with sulglycotide at 200 mg/kg or vehicle, were subjected to surface epithelial application of H. pylori lipopolysaccharide (50 microg/animal), and, after 4 additional days on the drug or vehicle regimen, their mucosal tissue was used for histologic assessment, quantitation of TNF-alpha and IL-4, and the assay of epithelial cell apoptosis. In the absence of sulglycotide, H. pylori lipopolysaccharide caused acute mucosal responses manifested by the inflammatory infiltration of the lamina propria with lymphocytes and plasma cells, edema, hyperemia, and epithelial hemorrhage. These responses were accompanied by an 11-fold increase in epithelial cell apoptosis and a 9-fold enhancement of the mucosal expression of proinflammatory cytokine TNF-alpha. However, the mucosal expression of regulatory cytokine IL-4 decreased by 15%. Treatment with sulglycotide produced significant (56.6%) reduction in the extent of acute mucosal inflammatory changes caused by H. pylori lipopolysaccharide. Moreover, the effect of sulglycotide was manifested in an 88.3% reduction in the epithelial cell apoptosis and a 69.1% decrease in the mucosal expression of TNF-alpha, whereas the expression of IL-4 showed only marginal (6%) enhancement. The results suggest that the cytoprotective agent sulglycotide suppresses the inflammatory and apoptotic events elicited in gastric mucosa by H. pylori lipopolysaccharide through stimulation of TNF-alpha expression.

  17. Enteric glia promote intestinal mucosal healing via activation of focal adhesion kinase and release of proEGF

    PubMed Central

    Van Landeghem, Laurianne; Chevalier, Julien; Mahé, Maxime M.; Wedel, Thilo; Urvil, Petri; Derkinderen, Pascal; Savidge, Tor

    2011-01-01

    Wound healing of the gastrointestinal mucosa is essential for the maintenance of gut homeostasis and integrity. Enteric glial cells play a major role in regulating intestinal barrier function, but their role in mucosal barrier repair remains unknown. The impact of conditional ablation of enteric glia on dextran sodium sulfate (DSS)-induced mucosal damage and on healing of diclofenac-induced mucosal ulcerations was evaluated in vivo in GFAP-HSVtk transgenic mice. A mechanically induced model of intestinal wound healing was developed to study glial-induced epithelial restitution. Glial-epithelial signaling mechanisms were analyzed by using pharmacological inhibitors, neutralizing antibodies, and genetically engineered intestinal epithelial cells. Enteric glial cells were shown to be abundant in the gut mucosa, where they associate closely with intestinal epithelial cells as a distinct cell population from myofibroblasts. Conditional ablation of enteric glia worsened mucosal damage after DSS treatment and significantly delayed mucosal wound healing following diclofenac-induced small intestinal enteropathy in transgenic mice. Enteric glial cells enhanced epithelial restitution and cell spreading in vitro. These enhanced repair processes were reproduced by use of glial-conditioned media, and soluble proEGF was identified as a secreted glial mediator leading to consecutive activation of epidermal growth factor receptor and focal adhesion kinase signaling pathways in intestinal epithelial cells. Our study shows that enteric glia represent a functionally important cellular component of the intestinal epithelial barrier microenvironment and that the disruption of this cellular network attenuates the mucosal healing process. PMID:21350188

  18. Augmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre

    NASA Astrophysics Data System (ADS)

    Grayson, Katie J.; Faries, Kaitlyn M.; Huang, Xia; Qian, Pu; Dilbeck, Preston; Martin, Elizabeth C.; Hitchcock, Andrew; Vasilev, Cvetelin; Yuen, Jonathan M.; Niedzwiedzki, Dariusz M.; Leggett, Graham J.; Holten, Dewey; Kirmaier, Christine; Neil Hunter, C.

    2017-01-01

    Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve the efficiency of light capture. Here, we show that a hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in the bacterium Rhodobacter sphaeroides. The structure of the RC/YFP-light-harvesting 1 (LH1) complex shows the position of YFP attachment to the RC-H subunit, on the cytoplasmic side of the RC complex. Fluorescence lifetime microscopy of whole cells and ultrafast transient absorption spectroscopy of purified RC/YFP complexes show that the YFP-RC intermolecular distance and spectral overlap between the emission of YFP and the visible-region (QX) absorption bands of the RC allow energy transfer via a Förster mechanism, with an efficiency of 40+/-10%. This proof-of-principle study demonstrates the feasibility of increasing spectral coverage for harvesting light using non-native genetically-encoded light-absorbers, thereby augmenting energy transfer and trapping in photosynthesis.

  19. Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry

    DOE PAGES

    Chen, Tsung-Chi; Fillmore, Thomas L.; Prost, Spencer A.; ...

    2015-06-24

    The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher pressure regions (e.g. ion source interfaces) of mass spectrometers, and thus providing increased sensitivity. An “off-axis” ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to charge ratios. In this study a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadruple mass spectrometer was developed and characterized. An orthogonal ionmore » injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at 9-10 Torr pressure. Several critical factors for the HPIF were characterized, including the effects of RF amplitude, DC gradient and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. Lastly, the sensitivity enhancement in liquid chromatography selected reaction monitoring (SRM) analyses of low abundance peptides spiked into a highly complex mixture was also compared with that obtained using a both commercial s-lens interface and a in-line dual ion funnel interface.« less

  20. Augmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre

    DOE PAGES

    Grayson, Katie J.; Faries, Kaitlyn M.; Huang, Xia; ...

    2017-01-05

    Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve the efficiency of light capture. Here, we show that a hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in the bacterium Rhodobacter sphaeroides. The structure of the RC/YFP-light-harvesting 1 (LH1) complex shows the position of YFP attachment to the RC-H subunit, on the cytoplasmic side of the RC complex. Fluorescence lifetime microscopy of whole cells and ultrafast transient absorption spectroscopy of purified RC/YFP complexes show that the YFP–RC intermolecular distance and spectral overlap between the emission of YFP and the visible-region (QX)more » absorption bands of the RC allow energy transfer via a Fo¨rster mechanism, with an efficiency of 40±10%. Finally, this proof-of-principle study demonstrates the feasibility of increasing spectral coverage for harvesting light using non-native genetically-encoded light-absorbers, thereby augmenting energy transfer and trapping in photosynthesis.« less

  1. Synergistic enhancement of nitrogen and sulfur co-doped graphene with carbon nanospheres insertion for electrocatalytic oxygen reduction reaction

    SciTech Connect

    Wu, Min; Xin, Huolin L.; Wang, Jie; Wu, Zexing; Wang, Deli

    2015-03-13

    A nitrogen and sulfur co-doped graphene/carbon black (NSGCB) nanocomposite for the oxygen reduction reaction (ORR) was synthesized through a one-pot annealing of a precursor mixture containing graphene oxide, thiourea, and acidized carbon black (CB). The NSGCB showed excellent performance for the ORR with the onset and half-way potentials at 0.96 V and 0.81 V (vs. RHE), respectively. It is significantly improved over that of the catalysts derived from only graphene (0.90 V and 0.76 V) or carbon nanosphere (0.82 V and 0.74 V). The enhanced catalytic activity on the NSGCB electrode could be attributed to the synergistic effect of N/S co-doping and the enlarged interlayer space resulted from the insertion of carbon nanosphere into the graphene sheets. The four-electron selectivity and the limiting current density of the NSGCB nanocomposite are comparable to that of the commercially Pt/C catalyst. Furthermore, the NSGCB nanocomposite was superior to Pt/C in terms of long-term durability and tolerance to methanol poisoning.

  2. Sensitive electrochemical immunoassay with signal enhancement based on nanogold-encapsulated poly(amidoamine) dendrimer-stimulated hydrogen evolution reaction.

    PubMed

    Sun, Ai-Li

    2015-12-07

    A new electrochemical immunosensor with signal enhancement was designed for sensitive detection of disease-related protein (human carbohydrate antigen 19-9, CA 19-9 used in this case). The assay was carried out on a capture antibody-modified screen-printed carbon electrode with a sandwich-type mode by using detection antibody-functionalized nanogold-encapsulated poly(amidoamine) dendrimer (AuNP-PAAD). The AuNP-PAAD was first synthesized through the in situ reduction method and functionalized with the polyclonal rabbit anti-human CA 19-9 antibody. Upon target CA 19-9 introduction, a sandwiched immunocomplex could be formed between the capture antibody and detection antibody. Accompanying the AuNP-PAAD, the electrocatalytic activity of the carried gold nanoparticles toward the hydrogen evolution reaction (HER) allowed the rapid quantification of the target analyte on the electrode. The amplified electrochemical signal mainly derived from AuNP-catalyzed HER in an acidic medium. Under optimal conditions, the immuno-HER assay displayed a wide dynamic concentration range from 0.01 to 300 U mL(-1) toward target CA 19-9 with a detection limit (LOD) of 6.3 mU mL(-1). The reproducibility, precision, specificity and stability of our strategy were acceptable. Additionally, the system was further validated by assaying 13 human serum specimens, giving well matched results obtained from the commercialized enzyme-linked immunosorbent assay (ELISA) method.

  3. A simple synthesis method for nanostructured Co-WC/carbon composites with enhanced oxygen reduction reaction activity

    PubMed Central

    Kang, Jun; Kim, Hye-min; Saito, Nagahiro; Lee, Myeong-Hoon

    2016-01-01

    Abstract Co nanoparticles (Co NPs) and nanoscale tungsten carbide (WC) are successfully synthesized simultaneously with mesoporous structured carbon black (C) using an innovative simple method, which is known as solution plasma processing (SPP), and NPs are also loaded onto carbon black at the same time by SPP. The introduction of Co NPs led to not only superior oxygen reduction reaction (ORR) activity in terms of onset potential and peak potential, but also to a more efficient electron transfer process compared to that of pure WC. Co-WC/C also showed durability for long-term operation better than that of commercial Pt/C. These results clearly demonstrate that the presence of Co NPs significantly enhanced the ORR and charge transfer number of neighboring WC NPs in ORR activities. In addition, it was proved that SPP is a simple method (from synthesis of NPs and carbon black to loading on carbon black) for the large-scale synthesis of NP-carbon composite. Therefore, SPP holds great potential as a candidate for next-generation synthetic methods for the production of NP-carbon composites. PMID:27877856

  4. Augmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre.

    PubMed

    Grayson, Katie J; Faries, Kaitlyn M; Huang, Xia; Qian, Pu; Dilbeck, Preston; Martin, Elizabeth C; Hitchcock, Andrew; Vasilev, Cvetelin; Yuen, Jonathan M; Niedzwiedzki, Dariusz M; Leggett, Graham J; Holten, Dewey; Kirmaier, Christine; Neil Hunter, C

    2017-01-05

    Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve the efficiency of light capture. Here, we show that a hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in the bacterium Rhodobacter sphaeroides. The structure of the RC/YFP-light-harvesting 1 (LH1) complex shows the position of YFP attachment to the RC-H subunit, on the cytoplasmic side of the RC complex. Fluorescence lifetime microscopy of whole cells and ultrafast transient absorption spectroscopy of purified RC/YFP complexes show that the YFP-RC intermolecular distance and spectral overlap between the emission of YFP and the visible-region (QX) absorption bands of the RC allow energy transfer via a Förster mechanism, with an efficiency of 40±10%. This proof-of-principle study demonstrates the feasibility of increasing spectral coverage for harvesting light using non-native genetically-encoded light-absorbers, thereby augmenting energy transfer and trapping in photosynthesis.

  5. Orthogonal Injection Ion Funnel Interface Providing Enhanced Performance for Selected Reaction Monitoring-Triple Quadrupole Mass Spectrometry

    SciTech Connect

    Chen, Tsung-Chi; Fillmore, Thomas L.; Prost, Spencer A.; Moore, Ronald J.; Ibrahim, Yehia M.; Smith, Richard D.

    2015-06-24

    The electrodynamic ion funnel facilitates efficient focusing and transfer of charged particles in the higher pressure regions (e.g. ion source interfaces) of mass spectrometers, and thus providing increased sensitivity. An “off-axis” ion funnel design has been developed to reduce the source contamination and interferences from, e.g. ESI droplet residue and other poorly focused neutral or charged particles with very high mass-to charge ratios. In this study a dual ion funnel interface consisting of an orthogonal higher pressure electrodynamic ion funnel (HPIF) and an ion funnel trap combined with a triple quadruple mass spectrometer was developed and characterized. An orthogonal ion injection inlet and a repeller plate electrode was used to direct ions to an ion funnel HPIF at 9-10 Torr pressure. Several critical factors for the HPIF were characterized, including the effects of RF amplitude, DC gradient and operating pressure. Compared to the triple quadrupole standard interface more than 4-fold improvement in the limit of detection for the direct quantitative MS analysis of low abundance peptides was observed. Lastly, the sensitivity enhancement in liquid chromatography selected reaction monitoring (SRM) analyses of low abundance peptides spiked into a highly complex mixture was also compared with that obtained using a both commercial s-lens interface and a in-line dual ion funnel interface.

  6. Augmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre

    PubMed Central

    Grayson, Katie J.; Faries, Kaitlyn M.; Huang, Xia; Qian, Pu; Dilbeck, Preston; Martin, Elizabeth C.; Hitchcock, Andrew; Vasilev, Cvetelin; Yuen, Jonathan M.; Niedzwiedzki, Dariusz M.; Leggett, Graham J.; Holten, Dewey; Kirmaier, Christine; Neil Hunter, C.

    2017-01-01

    Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve the efficiency of light capture. Here, we show that a hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in the bacterium Rhodobacter sphaeroides. The structure of the RC/YFP-light-harvesting 1 (LH1) complex shows the position of YFP attachment to the RC-H subunit, on the cytoplasmic side of the RC complex. Fluorescence lifetime microscopy of whole cells and ultrafast transient absorption spectroscopy of purified RC/YFP complexes show that the YFP–RC intermolecular distance and spectral overlap between the emission of YFP and the visible-region (QX) absorption bands of the RC allow energy transfer via a Förster mechanism, with an efficiency of 40±10%. This proof-of-principle study demonstrates the feasibility of increasing spectral coverage for harvesting light using non-native genetically-encoded light-absorbers, thereby augmenting energy transfer and trapping in photosynthesis. PMID:28054547

  7. Non-histone chromosomal proteins HMG1 and 2 enhance ligation reaction of DNA double-strand breaks.

    PubMed

    Nagaki, S; Yamamoto, M; Yumoto, Y; Shirakawa, H; Yoshida, M; Teraoka, H

    1998-05-08

    DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.

  8. Carbonization of self-assembled nanoporous hemin with a significantly enhanced activity for the oxygen reduction reaction.

    PubMed

    Xie, Yan; Tang, Chizhou; Hao, Zhiqiang; Lv, Yang; Yang, Ruixia; Wei, Xuming; Deng, Weiqiao; Wang, Anjie; Yi, Baolian; Song, Yujiang

    2014-01-01

    The scarcity and high cost of Pt-based electrocatalysts for the oxygen reduction reaction (ORR) hinder the practical application of proton exchange membrane fuel cells (PEMFCs). It is critical to replace platinum with non-noble metal electrocatalysts (NNMEs). Carbonized metalloporphyrins represent an important class of NNMEs, but most metalloporphyrins are costly and the corresponding NNMEs do not possess a high ORR activity. Herein, we report that the self-assembly of inexpensive hemin leads to porous nanomaterials in water under ambient conditions and subsequent heat-treatment of the unprecedented nanoporous hemin results in a magnetic NNME with a much enhanced ORR activity compared with directly carbonized hemin without self-assembly. The improvement of the ORR activity likely originates from the exposure of more ORR active sites, caused by the surface area increase of the nanoporous hemin after carbonization over that of micro-scale pristine hemin crystals. Moreover, the ORR activity of heat-treated nanoporous hemin is actually comparable to that of commercial Pt/C in alkaline solution. Additionally, the carbonized nanoporous hemin is much better than commercial Pt/C in terms of durability and tolerance to methanol. This study opens up a new avenue to the production of inexpensive metalloporphyrin-based NNMEs with a high ORR performance by using a self-assembly method in combination with traditional pyrolysis.

  9. Synergistic enhancement of nitrogen and sulfur co-doped graphene with carbon nanospheres insertion for electrocatalytic oxygen redu