Articles de revues : « Mer – Surfaces »

1

Yoshihiko, Amino. « Les Japonais et la mer ». Annales. Histoire, Sciences Sociales 50, n^o 2 (avril 1995) : 235–58. http://dx.doi.org/10.3406/ahess.1995.279364.

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L'archipel japonais compte plus de 3700 îles, grandes et petites, et possède un littoral de près de 28 000 kilomètres. Son relief est extrêmement tourmenté : les zones montagneuses, souvent volcaniques, occupent 60 % du territoire, les collines couvrent 11 % du pays et les piémonts 4 %. Plateaux et basses terres ne représentent guère plus de 25 % de la superficie du pays. Les rivières sont nombreuses et dévalent souvent les montagnes à une allure torrentielle. Les vallées sont encaissées et le terrain particulièrement accidenté. Les montagnes, les rivières et la mer occupent une part importante du paysage et, pour ceux qui vivent sur cet archipel, les surfaces cultivables n'ont jamais été très vastes.

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Consiglio, Giuseppe, et Giuseppe Forte. « Molecular dynamics study of coil-to-globule transition in a thermo-responsive oligomer bound to various surfaces : hydrophilic surfaces stabilize the coil form ». Physical Chemistry Chemical Physics 20, n^o 47 (2018) : 29754–63. http://dx.doi.org/10.1039/c8cp05396k.

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The structural and dynamical properties of 40-mer of thermo-responsive polymer PNIPAM covalently bound to different surfaces have been studied, at different temperatures, by means of molecular dynamics simulations.

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Britten, Michel, Margaret L. Green, Marcel Boulet et Paul Paquin. « Deposit formation on heated surfaces : effect of interface energetics ». Journal of Dairy Research 55, n^o 4 (novembre 1988) : 551–62. http://dx.doi.org/10.1017/s0022029900033331.

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SummaryDeposit formation was measured in a model laboratory plant in which whole milk was in contact with a heated surface at 100 °C for 1 h. The effect of the interfacial properties of various poly mer-coated surfaces on the amount and the adhesion strength of deposit was determined. The nature of the surface influenced the formation of deposit only slightly, but had a large effect on its adhesion strength. From correlation analysis, the polar contribution to surface energy was identified as the main factor influencing the deposit adhesion strength. These results suggest that the type of interactions at the surface govern the ease of removal of deposit.

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Guney, Dilvin, Aysin Tulunay, Funda Pepedil, Isik Kaygusuz, Cafer Adiguzel, Tülin Tuglular, Muzaffer Demir, Emel Eksioglu-Demiralp et Fikriye Uras. « Tyro3, Axl Ve Mer (TAM) Receptors On Surfaces of Mononuclear Cells in Patients with B-Cell Chronic Lymphocytic Leukemia ». Blood 120, n^o 21 (16 novembre 2012) : 4588. http://dx.doi.org/10.1182/blood.v120.21.4588.4588.

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Abstract Abstract 4588 Background: Tyro 3 (Sky), Axl, and Mer receptors are members of the family of tyrosine kinases and Gas6 is their ligand molecule. In some types of cancer, upregulation of Axl/Gas6 indicated a worse prognosis, but an opposite situation was observed in renal “cell” carcinoma. This contradiction may suggest that Axl/Gas6 pathway varies depending on the type of cancer. The objective of this study is to investigate TAM receptors on surfaces of mononuclear cells in patients with B-Cell chronic lymphocytic leukemia (B-Cell-CLL). Material & Methods: B-Cell-CLL patients (grade 0–1, according to the classification of RAI), who were not on a drug treatment, were recruited in this study (n= 20; 9 female, 11 male). Their ages were 44 to 74 (mean: 63), and the control group consisted of 13 healthy volunteers (5 female, 8 male), whose age range is 20–89 (mean: 36). Mononuclear cells were isolated by density gradient centrifugation, and then surface TAM receptors were detected by flow cytometry. Mononuclear cell were stained with the primary antibodies against Tyro3, Axl and Mer. Results: The percentage of the surface TAM receptors on mononuclear cells from the patient group (25–75% interquartile range): Tyro 3= 25.50 (4.2– 45.62); Axl= 17/55 (5.57– 36.32), and Mer= 19.90 (1.92– 37.55). In the control group the following values were obtained: Tyro 3= 2.60 (1.35–3.25); Axl= 0.9 (0.4–2.6), and Mer= 2.50 (0.35–3.65). The percentage of three of them was significantly higher in the B-Cell-CLL group than those in the control group (P<0.01). Conclusion: In conclusion, this preliminary study showed that TAM receptors on surfaces of mononuclear cells are higher in patients with B-Cell-CLL patients than the control group. Gas6/TAM signaling may play a potential role in the pathogenesis of B Cell-CLL. Further studies are required to elucidate the actual role of Gas6/TAM signaling in B-Cell-CLL. Gas6/TAM signaling might be a new strategic goal for the treatment of B-Cell-CLL. Disclosures: No relevant conflicts of interest to declare.

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Branchford, Brian R., Luke Law, Susan Sather, Gary Brodsky, H. Shelton Earp, Xiaodong Wang, Stephen Frye, Douglas K. Graham et Jorge A. Di Paola. « A Small Molecule Inhibitor of the Gas6/Mer Pathway Inhibits Platelet Activation and Thrombosis with Equal Efficacy to, but Greater Potency Than, iMer, the Novel MerTK Splice Variant ». Blood 120, n^o 21 (16 novembre 2012) : 3303. http://dx.doi.org/10.1182/blood.v120.21.3303.3303.

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Abstract Abstract 3303 Background: Growth Arrest Specific gene 6 (Gas6) signals through platelet-surface Mer receptors, leading to platelet activation and thrombus stabilization via activation of PI3K and Akt, and β3 integrin phosphorylation. This amplifies outside-in signaling via αIIb β3, a necessary step for stable platelet aggregation. iMer is a truncated form of the Mer receptor tyrosine kinase's extracellular domain, produced by alternative splicing, that inhibits Gas6 signaling. A selective UNC Mer small molecule inhibitor (UNC Mer TKI) inhibits signaling by inhibiting Mer tyrosine phosphorylation. Objectives: We hypothesized that inhibiting the Gas6/Mer pathway with UNC Mer TKI would decrease platelet activation responses and thrombus formation to a greater degree than iMer. So, we comparatively evaluated iMer's and UNC Mer TKI's inhibition of Gas6/Mer signaling in vitro and in vivo. Methods: We measured the effect on platelet inhibiton of iMer and UNC Mer TKI using lab assays of human platelet function and murine thrombosis models. In vitro studies included standard aggregometry and aggregate formation on collagen surfaces in a microfluidic flow chamber. In vivo studies included a FeCl3-induced model of carotid artery injury and a collagen/epinephrine-induced pulmonary embolism (PE) model to compare thrombosis protection between littermate C57BL/6 mice treated with inhibitors or vehicle control. A paired t-test was used to compare samples in aggregation, microfluidic flow surface area coverage, as well as elapsed time to initial and stable occlusions in the FeCl3model and survival time in the PE model. Results/Discussion: Inhibitor-treated platelets exhibited significantly decreased aggregation. Collagen-stimulated samples treated with 1.2 μM iMer had mean aggregation of 45 +/− 13% (Stand Dev), compared to 72 +/− 8% in controls (n=6, p=0.02). 1.2 μM UNC Mer TKI-treated samples had mean aggregation of 56 +/−15%, compared to 74 +/−10% in controls (n=5, p<0.01). Adhesion of platelets to collagen under physiologic flow conditions resulted in 1.9% (+/− 1%) coverage in 1.2 μM iMer-treated samples compared to 8.7 +/− 2% mean surface area coverage in controls (n=7, p<0.001). 1.2 μM UNC Mer TKI-treated samples exhibited 8.5 +/−8.8% surface area coverage, compared to 19.2 +/− 15.7% for control-treated samples (n=5 in quadruplicate, p<0.01), and 2.4 +/−1.7% for abciximab-treated positive controls. Both iMer- and UNC Mer TKI-treated samples have a higher average percentage of small platelet aggregates (1–10 platelets/aggregate) compared to controls, which had a higher average percentage of large aggregates (>10 platelets/aggregate). Following 6% FeCl3-induced carotid artery injury for analysis of iMer's thrombosis protection, vehicle-treated control mice (n=6) had a hazard ratio for stable artery occlusion of 7.9 (95%CI 1.7–36.3) compared to 30mg/kg iMer-treated mice (n=8, p<0.01). The 1.2 μM iMer treated mice also demonstrated significantly prolonged time to both initial (p=0.03) and stable occlusion (p=0.02), suggesting decreased thrombus stability. In analysis of UNC Mer TKI's thrombosis inhibition, vehicle-treated control mice (n=10) had a hazard ratio for stable artery occlusion of 4.8 (95%CI 1.4–15.8) compared 3 mg/kg UNC Mer TKI-treated mice (n=9, p=0.02). Times to initial (p=0.06) and stable (p<0.01) occlusions were also prolonged in the UNC Mer TKI-treated mice compared to controls. In the PE model, 1.2 μM iMer-treated mice (n=5) had longer mean survival (14.1 +/− 14.5 min) following collagen/epinephrine injection than controls (n=5, 1.78 +/12.4 min, p=NS), with 2 iMer–treated mice and no controls surviving for 30 min. A much greater effect was seen with the 3 mg/kg UNC Mer TKI-treated mice (n=5) who had a mean survival time of 37.24 +/−31.2 min, with 3 surviving for a full 60 min, compared to 1.63 +/− 0.6 min (p=0.03) for controls (n=5), of which only 1 survived for 60 min. Conclusions: iMer and UNC Mer TKI are Gas6/Mer inhibitors that decrease platelet activation and protect mice from thrombosis, and may have translational applications as novel anti-platelet agents. UNC Mer TKI has similar efficacy, and higher potency, especially in the animal models where similar (FeCl3 model) or superior (PE model) results were seen with a 10-fold lower concentration. UNC Mer TKI also has the advantage of possible oral preparation, which may increase its potential therapeutic appeal. Disclosures: Branchford: University of Colorado: This author has provisional patent considerations for iMer, This author has provisional patent considerations for iMer Patents & Royalties. Sather:University of Colorado: This author has provisional patent considerations for iMer, This author has provisional patent considerations for iMer Patents & Royalties. Brodsky:University of Colorado: This author has provisional patent considerations for iMer, This author has provisional patent considerations for iMer Patents & Royalties. Graham:University of Colorado: This author has provisional patent considerations for iMer, This author has provisional patent considerations for iMer Patents & Royalties.

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Zhou, Junsong, Lu Wang et Yi Wu. « Gas6 Receptors, Tyro3, Axl and Mer, Differentially Participate in Glycoprotein VI-Mediated Platelet activation ». Blood 118, n^o 21 (18 novembre 2011) : 364. http://dx.doi.org/10.1182/blood.v118.21.364.364.

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Abstract Abstract 364 Growth arrest-specific gene 6 (Gas6) has three receptors on platelets - Tyro3, Axl and Mer. It has been shown that these three receptors are equally important in platelet activation (J Clin Invest. 2005;115:237–46), and they synergizes with ADP receptor for platelet activation, but not with collagen receptor (J Thromb Haemost. 2010;8:1797–808). Considering the fact that Tyro3, Axl or Mer plays a distinct role in the function of endothelial cells and leukocytes, we hypothesized that these three receptors play specific role in platelet activation, and examined the role of each receptor in Gycoprotein VI (GPVI)-mediated platelet activation using single receptor knockout mice. In response to 100 ng/ml convulxin or 5 ng/ml poly(PHG), a GPVI-specific synthetic peptide, the aggregation of Axl−/− or Tyro3−/− platelets was almost completely prevented. However, the aggregation of Mer−/− platelets was only delayed, and still could reach the maximum level. In the presence of 100 ng/ml convulxin or 5 ng/ml poly(PHG), the spreading of Axl−/− or Tyro3−/− platelets, but not Mer−/− platelets, on fibrinogen-coated surfaces was markedly inhibited. Moreover, convulxin-stimulated P-selectin expression and JON/A binding were both significantly decreased in Axl−/− and Tyro3−/− platelets, but not in Mer−/− platelets. Upon stimulation with 100 ng/ml convulxin, tyrosine phosphorylation of Syk, linker for activation of T cells (LAT), SLP-76(SH2 domain-containing leukocyte protein of 76) and phospholipase C (PLCγ2) was markedly reduced in the Axl−/− or Tyro3−/− platelets, but not in the Mer−/− platelets. Interestingly, anti-Axl or anti-Tyro3 antibody (20 mg/ml) completely blocked convulxin-stimulated human platelet aggregation, however, the neutralizing anti-Gas6 antibody (60 mg/ml) did not have any effect, suggesting the homodimer formation of Axl or Tyro3 is involved in GPVI-mediated platelet activation. As detected by flow cytometry, there was no difference in the expression of GPVI and integrin aIIbb3 on membrane surface among Tyro-3−/−, Axl−/−, Mer−/− and wild type platelets. In conclusion, Gas6 receptors are not equally important in platelet activation, Axl and Tyro3 play more critical role than Mer in GPVI-mediated platelet activation. The trans-interaction of Axl or Tyro3 mediates cell-cell contact-dependent activation, which facilitates the activation of GPVI in platelets. Thus, Axl and Tyro3 may serve as better targets than Mer for the development of new antiplatelet agents. Disclosures: No relevant conflicts of interest to declare.

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Jousselme, A., D. Grenier et H. T. Huynh. « Analyse de la distorsion spectrale des images radar de surfaces de mer ». Canadian Journal of Electrical and Computer Engineering 29, n^o 4 (octobre 2004) : 243–51. http://dx.doi.org/10.1109/cjece.2004.1426052.

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Barragan, Antonio, Victor Fernandez, Qijun Chen, Anne von Euler, Mats Wahlgren et Dorothe Spillmann. « The Duffy-binding-like domain 1 of Plasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) is a heparan sulfate ligand that requires 12 mers for binding ». Blood 95, n^o 11 (1 juin 2000) : 3594–99. http://dx.doi.org/10.1182/blood.v95.11.3594.

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Abstract The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), present on the surfaces of parasitized red blood cells (pRBC), mediates rosetting, a virulent phenotype. Here, we show that pRBC specifically bind heparan sulfate (HS) and heparin onto their surfaces and that the rosetting ligand PfEMP1 specifically adheres to heparin–Sepharose when extracted from the surfaces of radioiodinated infected RBC. An analysis of the binding properties of the different regions of PfEMP1 provides evidence that the Duffy-binding–like domain-1 (DBL-1) is the predominant ligand involved in HS and heparin binding. Soluble DBL-1 requires a minimal heparin fragment size of a 12-mer (≈4 kd) for binding and is critically dependent on N-sulfation. A 12-mer is also the minimal heparin fragment that disrupts naturally formed rosettes. DBL-1 binds specifically to erythrocytes and also to HS from endothelial cells and human aorta but not to chondroitin sulfate A, suggesting that different PfEMP1s mediate adhesion to distinct glycosaminoglycans in individual malaria parasites. Present data suggest that HS on endothelial cells may also be involved in the sequestration of pRBC. Elucidation of these binding mechanisms opens up new possibilities for therapeutic strategies targeting adhesive interactions of pRBC.

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Barragan, Antonio, Victor Fernandez, Qijun Chen, Anne von Euler, Mats Wahlgren et Dorothe Spillmann. « The Duffy-binding-like domain 1 of Plasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) is a heparan sulfate ligand that requires 12 mers for binding ». Blood 95, n^o 11 (1 juin 2000) : 3594–99. http://dx.doi.org/10.1182/blood.v95.11.3594.011k21_3594_3599.

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The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), present on the surfaces of parasitized red blood cells (pRBC), mediates rosetting, a virulent phenotype. Here, we show that pRBC specifically bind heparan sulfate (HS) and heparin onto their surfaces and that the rosetting ligand PfEMP1 specifically adheres to heparin–Sepharose when extracted from the surfaces of radioiodinated infected RBC. An analysis of the binding properties of the different regions of PfEMP1 provides evidence that the Duffy-binding–like domain-1 (DBL-1) is the predominant ligand involved in HS and heparin binding. Soluble DBL-1 requires a minimal heparin fragment size of a 12-mer (≈4 kd) for binding and is critically dependent on N-sulfation. A 12-mer is also the minimal heparin fragment that disrupts naturally formed rosettes. DBL-1 binds specifically to erythrocytes and also to HS from endothelial cells and human aorta but not to chondroitin sulfate A, suggesting that different PfEMP1s mediate adhesion to distinct glycosaminoglycans in individual malaria parasites. Present data suggest that HS on endothelial cells may also be involved in the sequestration of pRBC. Elucidation of these binding mechanisms opens up new possibilities for therapeutic strategies targeting adhesive interactions of pRBC.

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Riul, A., A. Dhanabalan, L. H. C. Mattoso, L. M. de Souza, E. A. Ticianelli et O. N. Oliveria. « Characterization of 16-mer polyaniline composite Langmuir–Blodgett films ». Thin Solid Films 327-329 (août 1998) : 576–80. http://dx.doi.org/10.1016/s0040-6090(98)00716-0.

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Mebus-Antunes, Nathane C., Wellington S. Ferreira, Glauce M. Barbosa, Thais C. Neves-Martins, Gilberto Weissmuller, Fabio C. L. Almeida et Andrea T. Da Poian. « The interaction of dengue virus capsid protein with negatively charged interfaces drives the in vitro assembly of nucleocapsid-like particles ». PLOS ONE 17, n^o 3 (1 mars 2022) : e0264643. http://dx.doi.org/10.1371/journal.pone.0264643.

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Dengue virus (DENV) causes a major arthropod-borne viral disease, with 2.5 billion people living in risk areas. DENV consists in a 50 nm-diameter enveloped particle in which the surface proteins are arranged with icosahedral symmetry, while information about nucleocapsid (NC) structural organization is lacking. DENV NC is composed of the viral genome, a positive-sense single-stranded RNA, packaged by the capsid (C) protein. Here, we established the conditions for a reproducible in vitro assembly of DENV nucleocapsid-like particles (NCLPs) using recombinant DENVC. We analyzed NCLP formation in the absence or presence of oligonucleotides in solution using small angle X-ray scattering, Rayleigh light scattering as well as fluorescence anisotropy, and characterized particle structural properties using atomic force and transmission electron microscopy imaging. The experiments in solution comparing 2-, 5- and 25-mer oligonucleotides established that 2-mer is too small and 5-mer is sufficient for the formation of NCLPs. The assembly process was concentration-dependent and showed a saturation profile, with a stoichiometry of 1:1 (DENVC:oligonucleotide) molar ratio, suggesting an equilibrium involving DENVC dimer and an organized structure compatible with NCLPs. Imaging methods proved that the decrease in concentration to sub-nanomolar concentrations of DENVC allows the formation of regular spherical NCLPs after protein deposition on mica or carbon surfaces, in the presence as well as in the absence of oligonucleotides, in this latter case being surface driven. Altogether, the results suggest that in vitro assembly of DENV NCLPs depends on DENVC charge neutralization, which must be a very coordinated process to avoid unspecific aggregation. Our hypothesis is that a specific highly positive spot in DENVC α4-α4’ is the main DENVC-RNA binding site, which is required to be firstly neutralized to allow NC formation.

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Nguyen, Jennifer M., Martin Gilar, Brooke Koshel, Michael Donegan, Jason MacLean, Zhimin Li et Matthew A. Lauber. « Assessing the impact of nonspecific binding on oligonucleotide bioanalysis ». Bioanalysis 13, n^o 16 (août 2021) : 1233–44. http://dx.doi.org/10.4155/bio-2021-0115.

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Aim: Accurate and reliable quantification of oligonucleotides can be difficult, which has led to an increased focus on bioanalytical methods for more robust analyses. Recent advances toward mitigating sample losses on liquid chromatography (LC) systems have produced recovery advantages for oligonucleotide separations. Results & methodology: LC instruments and columns constructed from MP35N metal alloy and stainless steel columns were compared against LC hardware modified with hybrid inorganic-organic silica surfaces. Designed to minimize metal-analyte adsorption, these surfaces demonstrated a 73% increase in 25-mer phosphorothioate oligonucleotide recovery using ion-pairing reversed-phase LC versus standard LC surfaces, most particularly upon initial use. Conclusion: Hybrid silica chromatographic surfaces improve the performance, detection limits and reproducibility of oligonucleotide bioanalytical assays.

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Lehmann, Benjamin, Frédéric Herman, Pierre G. Valla, Georgina E. King, Rabiul H. Biswas, Susan Ivy-Ochs, Olivia Steinemann et Marcus Christl. « Postglacial erosion of bedrock surfaces and deglaciation timing : New insights from the Mont Blanc massif (western Alps) ». Geology 48, n^o 2 (22 novembre 2019) : 139–44. http://dx.doi.org/10.1130/g46585.1.

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Abstract Since the Last Glacial Maximum, ∼20 k.y. ago, Alpine glaciers have retreated and thinned. This transition exposed bare bedrock surfaces that could then be eroded by a combination of debuttressing or local frost cracking and weathering. Quantification of the respective contributions of these processes is necessary to understand the links between long-term climate and erosion in mountains. Here, we quantified the erosion histories of postglacial exposed bedrock in glacial valleys. Combining optically stimulated luminescence and terrestrial cosmogenic nuclide (TCN) surface exposure dating, we estimated the erosion rate of bedrock surfaces at time scales from 101 to 104 yr. Bedrock surfaces sampled from the flanks of the Mer de Glace (Mont Blanc massif, European Alps) revealed erosion rates that vary from 3.5 ± 1.2 ⋅ 10−3 mm/yr to 4.3 ± 0.6 mm/yr over ∼500 m of elevation, with a negative correlation between erosion rate and elevation. The observed spatial variation in erosion rates, and their high values, reflect morphometric (elevation and surface slope) and climatic (temperature and snow cover) controls. Furthermore, the derived erosion rates can be used to correct the timing of deglaciation based on TCN data, potentially suggesting very rapid ice thinning during the Gschnitz stadial.

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Ie, Yutaka, Aihong Han, Tetsuo Otsubo et Yoshio Aso. « Completely encapsulated oligothiophenes up to 12-mer ». Chemical Communications, n^o 21 (2009) : 3020. http://dx.doi.org/10.1039/b901354g.

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Cauderay, Gérald C. « Visibilité du signe distinctif des établissements, des formations et des transports sanitaires ». Revue Internationale de la Croix-Rouge 72, n^o 784 (août 1990) : 319–47. http://dx.doi.org/10.1017/s0035336100013186.

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Les Conventions de Genève du 12 août 1949 prévoient comme moyen général d'identification du personnel et du matériel sanitaires le signe distinctif de la croix rouge ou du croissant rouge. La IIe Convention de Genève, applicable aux victimes des conflits sur mer, précise en plus la couleur blanche pour les surfaces extérieures des navires hôpitaux et embarcations sanitaires et elle recommande aux parties en conflit d'utiliser «les méthodes les plus modernes” pour faciliter l'identification des moyens de transport sanitaires maritimes (article 43).

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Sitthiyotha, Thassanai, et Surasak Chunsrivirot. « Computational Design of 25-mer Peptide Binders of SARS-CoV-2 ». Journal of Physical Chemistry B 124, n^o 48 (17 novembre 2020) : 10930–42. http://dx.doi.org/10.1021/acs.jpcb.0c07890.

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Klotz, Stephen A., Nand K. Gaur, Jason Rauceo, Douglas F. Lake, Y. Park, K. S. Hahm et Peter N. Lipke. « Inhibition of Adherence and Killing of Candida albicans with a 23-Mer Peptide (Fn/23) with Dual Antifungal Properties ». Antimicrobial Agents and Chemotherapy 48, n^o 11 (novembre 2004) : 4337–41. http://dx.doi.org/10.1128/aac.48.11.4337-4341.2004.

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ABSTRACT Candida albicans adheres to host tissue and then proliferates in order to establish a commensal as well as a pathogenic state. Specific adherence to proteins is provided by several surface adhesins of Candida. Two well-studied proteins, Als1p and Als5p, do not require energy for adherence to occur (dead as well as living cells adhere) and have a multiplier effect of cell-cell aggregation that mediates the formation of microcolonies of Candida cells. The entire process is spontaneous, reversible, and stable for physiologically relevant chemical and physical forces. This adherence process is inhibited by the addition of free peptide ligands, including a 23-mer derived from fibronectin (Fn/23) that binds to the adhesins through H bond formation. Adherence was measured by determining the number of yeast cells that adhered to 90-μm-diameter polyethylene glycol (PEG) beads with a 7-mer peptide (KLRIPSV) synthesized on the surfaces of the beads. The concentration of the Fn/23 peptide that inhibited the adherence of cells to the peptide-coated beads by 50% was 4 to 5 μM, and the magnitudes of adherence were similar regardless of the presence or absence of physiologic salt concentrations. The minimum fungicidal concentration of Fn/23 was 2 to 4 μM in water, but there was no killing in physiologic salt concentrations. Peptides from the C and N termini or the center sequence of Fn/23 had no effect on inhibition of adherence and little effect on fungal viability. The fungicidal effect was similar to that seen with 23-, 19-, and 18-mer peptides derived from porcine myeloid cells, a Helicobacter pylori ribosomal protein, and a hybrid of cecropin and magainin, respectively. However, these fungicidal peptides did not inhibit C. albicans adherence to the peptide-coated PEG beads. This dual property of Fn/23, i.e., inhibition of adherence and killing of C. albicans, may provide important adjuvant effects in the treatment of disease caused by this fungus.

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OZAWA, HIROAKI, et TAKUJI OGAWA. « SYNTHESIS OF THICK PORPHYRIN MOLECULAR WIRES BY A PALLADIUM CATALYZED OLIGOMERIZATION ». International Journal of Nanoscience 01, n^o 05n06 (octobre 2002) : 483–87. http://dx.doi.org/10.1142/s0219581x02000541.

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In the aim to prepare thick porphyrin molecular wires, which is visible by atomic force microscopy (AFM), even on the rough surfaces of nanogap electrodes fabricated by electron beam lithography, dendrimer protected porphyrins whose two meso-positions are substituted with ethynyl groups. The porphyrin monomer was reacted with palladium catalyst to make oligomers. Analyses of them with time-of-flight mass spectroscopy (TOF-MS), gel-permeation-chromatography (GPC) revealed that the oligomers were distributed up to 16 mer, whose molecular weight was about 38 000 Daltons.

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MacPherson, Joyce Brown. « Raised Shorelines and Drainage Evolution in the Montréal Lowland ». Cahiers de géographie du Québec 11, n^o 23 (12 avril 2005) : 343–60. http://dx.doi.org/10.7202/020731ar.

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La rive la plus élevée de la mer Champlain, qui a envahi les Basses-Terres du Saint-Laurent après la dernière glaciation, a été identifiée à une altitude de 750 pieds au nord de Montréal, et de 525 pieds au sud. Une rive plus récente parcourt toute la région à une altitude uniforme de 100 pieds. Les rivages intermédiaires résultent de pulsations variables de la mer, mais leur répartition et leur nature même rendent difficile la corrélation du niveau des eaux par des méthodes statistiques. Cependant, la preuve est maintenant établie qu'il est possible de localiser les niveaux intermédiaires par l'analyse du pollen. L'accumulation de sédiments renfermant du pollen est plus ancienne dans les secteurs les plus élevés, évacués les premiers par les eaux, et les échantillons positifs tirés de tourbières choisies permettent d'établir les différentes altitudes des surfaces séparant ces tourbières qui se sont développées dans les zones anciennes et plus récentes recelant du pollen. La surface séparant les tourbières datant de la zone IV de pollen (récente) de celle de la zone V (plus ancienne) a été remaniée et se situe à 230 pieds d'altitude au nord de Montréal et à 170 pieds au sud. La déclivité nord-sud de cette surface est de 1.25 pied au mille, ce qui correspond à une rive bien déterminée à une altitude équivalente. Dans la basse vallée de l'Outaouais. Une preuve plus poussée de la validité de la méthode est fournie par la nature horizontale de la surface séparant les tourbières datant des zones de pollen n° III et IV, à la même altitude que la ligne de rivage de 100 pieds. Un rivage inférieur, par exemple à une altitude de 50 pieds, ne peut être daté selon cette méthode. Les noms de Rigaud, Montréal et Saint-Barthélémi, sont proposés pour nommer les rives s'élevant respectivement à 200, 150 et 50 pieds d'altitude. Au stade « Rigaud », les eaux envahissaient les vallées de l'Outaouais, du Saint-Laurent et du Richelieu. Au stade « Montréal », le lac Saint-François, section du Saint-Laurent, a été séparé du corps principal de la mer de Champlain, tandis que le lac Champlain, le lac des Deux-Montagnes et le lac Saint-Louis se sont successivement séparés durant le stade transitoire « Montréal - Saint-Barthélémi ».

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Kochetov, N. A., et I. D. Kovalev. « Features of SHS of multicomponent carbides ». Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya, n^o 4 (10 décembre 2022) : 58–66. http://dx.doi.org/10.17073/1997-308x-2022-4-58-66.

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Combustion of powders of transition metals of titanium PTS (average particle size 57 μm), zirconium PCRK-1 (12 μm), tantalum Ta PM-3 (8 μm), hafnium GFM-1 (4 μm), niobium NBP-1a (21 μm) with carbon black grade P-803 dispersion 1–2 μm was studied. The combustion process of the compressed samples (mass 2.5–6.9 g, height 1.2–1.7 cm, relative density 0.55–0.61) was performed in an inert argon medium at a pressure of 760 mmHg in the constant pressure chamber. Combinations were studied, Me1 + Me2 + Me3 + Me4 + 4C, Me1 + Me2 + Me3 + Me4 + Me5 + 5C. XRD patterns of the mixtures were recorded on a DRON-3М diffractometer (CuKα-radiation). Combustion product sections were studied using a LEO 1450 VP scanning electron microscope (Carl Zeiss, Germany). The fractional composition and particle size distribution of the mixture were determined according to standard procedure using a Microsizer-201C laser particle size analyzer. Combustion velocity, elongation of samples, phase composition of products were determined. The maximum combustion temperature of the mixture (Ti + Hf + Zr + Nb + Ta) + 5C was measured experimentally for the first time. The morphology and microstructure of the reaction products were also observed. Combustion products of mixtures (Ti + Zr + Nb + Ta) + 4C and (Ti + Zr + Nb + Hf) + 4C contain high entropy carbides, which are solid solutions with the same structural type B1 (space group Fm-3m) and having different cell parameters. Product samples of mixtures (Ti + Zr ++ Hf + Ta) + 4C and (Ti + Hf + Zr + Nb + Ta) + 5C contain high entropy and medium entropy carbides, also representing solid solutions with the same structural type B1 (space group Fm-3m). The results of this work can be used in the production of high-entropy and medium-entropy multicomponent carbides.

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Abd El-Mageed, Ahmed I. A., et Takuji Ogawa. « Identification of Supramolecular Structures of Porphyrin Polymer on Single-Walled Carbon Nanotube Surface Using Microscopic Imaging Techniques ». Polymers 15, n^o 6 (14 mars 2023) : 1439. http://dx.doi.org/10.3390/polym15061439.

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Although the supramolecular structure of porphyrin polymers on flat surfaces (i.e., mica and HOPG) has been extensively studied, the self-assembly arrays of porphyrin polymers on the SWNT (as curved nanocarbon surfaces) have yet to be fully identified and/or investigated, especially using microscopic imaging techniques, i.e., scanning tunneling microscopy (STM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). This study reports the identification of the supramolecular structure of poly-[5,15-bis-(3,5-isopentoxyphenyl)-10,20-bis ethynylporphyrinato]-zinc (II) on the SWNT surface using mainly AFM and HR-TEM microscopic imaging techniques. After synthesizing around >900 mer of porphyrin polymer (via Glaser-Hay coupling); the as-prepared porphyrin polymer is then non-covalently adsorbed on SWNT surface. Afterward, the resultant porphyrin/SWNT nanocomposite is then anchored with gold nanoparticles (AuNPs), which are used as a marker, via coordination bonding to produce a porphyrin polymer/AuNPs/SWNT hybrid. The polymer, AuNPs, nanocomposite, and/or nanohybrid are characterized using 1H-NMR, mass spectrometry, UV-visible spectroscopy, AFM, as well as HR-TEM measuring techniques. The self-assembly arrays of porphyrin polymers moieties (marked with AuNPs) prefer to form a coplanar well-ordered, regular, repeated array (rather than wrapping) between neighboring molecules along the polymer chain on the tube surface. This will help with further understanding, designing, and fabricating novel supramolecular architectonics of porphyrin/SWNT-based devices.

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Grobe, George L., Anthony S. Nagel, Joseph A. Gardella, Roland L. Chin et Lawrence Salvati. « Characterization of Solution-Cast Extracts from Cardiothane-51 ® by FT-IR and ESCA ». Applied Spectroscopy 42, n^o 6 (août 1988) : 980–89. http://dx.doi.org/10.1366/0003702884430506.

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Extracts from Cardiothane-51 ® have been cast from solvents of varying polarity. Cardiothane-51® can be described as block polyether-polyurethane copolymer with a 10% by weight addition of polydimethylsiloxane (DMS) that is partially copolymerized and partially blended to form a copolv mer/polv blend. FT-IR has been utilized to probe bulk and near-surface bonding and composition in the solution-cast extract films. Results show that Cardiothane-51 ® is similar in bulk composition, as measured by FT-IR, to Avcothane-51®. However, these two polymers are quite different in composition over a depth of microns. Both Cardiothane-51 ® and Avcothane-51 ® have surfaces, as measured by ESCA, which are dominated by their DMS component with a significant amount of the polyether present. Results suggest that the DMS in Cardiothane-51 ® is a blended phase, because of its ease of extraction.

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Xu, Fang, Qinwei Lu, Po-Jung Jimmy Huang et Juewen Liu. « Nanoceria as a DNase I mimicking nanozyme ». Chemical Communications 55, n^o 88 (2019) : 13215–18. http://dx.doi.org/10.1039/c9cc06782e.

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Ueki, Ryosuke, Saki Atsuta, Ayaka Ueki, Junya Hoshiyama, Jingyue Li, Yohei Hayashi et Shinsuke Sando. « DNA aptamer assemblies as fibroblast growth factor mimics and their application in stem cell culture ». Chemical Communications 55, n^o 18 (2019) : 2672–75. http://dx.doi.org/10.1039/c8cc08080a.

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Smith, Daniel J., William F. King, Joy Rivero et Martin A. Taubman. « Immunological and Protective Effects of Diepitopic Subunit Dental Caries Vaccines ». Infection and Immunity 73, n^o 5 (mai 2005) : 2797–804. http://dx.doi.org/10.1128/iai.73.5.2797-2804.2005.

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ABSTRACT As a prelude to development of broader-spectrum vaccines for dental caries, we explored the immune potential of constructs combining epitopes from mutans streptococcal glucosyltransferases (GTF) and glucan binding protein B (GbpB). Two diepitopic peptide constructs were synthesized in a multiple antigenic peptide (MAP) format. Both constructs contained SYI, a 20-mer GbpB peptide that included a sequence having major histocompatibility complex class II binding characteristics. One diepitopic construct (SYI-CAT) also contained a 22-mer sequence from the catalytic domain of GTF. Another diepitopic construct (SYI-GLU) contained a 22-mer sequence from the glucan binding domain of GTF. To assess the ability of each construct to induce antibody reactive with GbpB and GTF native proteins, rats were injected subcutaneously with SYI-CAT, SYI-GLU, or the constituent monoepitopic constructs. Only the SYI-CAT construct induced significant levels of serum immunoglobulin G (IgG) and IgA antibody to both pathogenesis-associated proteins. Also, immunization with SYI-CAT significantly (P < 0.001) enhanced the antibody response to the CAT peptide. Experiments then compared experimental dental caries after immunization with SYI-CAT, SYI, or CAT MAP constructs, followed by infection with Streptococcus mutans strain SJr. Dental caries were lower in each peptide-immunized group than in the sham-injected group. The level of protection after SYI-CAT immunization was similar to that after immunization with constituent MAP constructs. In another experiment, rats were infected with Streptococcus sobrinus strain 6715 under an identical protocol. Significant protection was observed on buccal surfaces in both SYI-CAT and CAT construct-immunized, but not in the SYI construct-immunized, groups. Thus, addition of the GbpB-derived SYI peptide to the GTF-derived CAT peptide construct not only enhanced the immunological response to CAT and GTF epitopes, but also extended the protective effect of the construct to include both S. mutans and S. sobrinus.

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Jiang, X., A. Israyeeyan, E. Boykin, L. Lomax, J. F. Head et R. L. Elliott. « Antisense oligonucleotide targeted to the transferrin receptor gene suppresses tumor growth and lung metastases in 4T1 mammary adenocarcinoma mouse model ». Journal of Clinical Oncology 24, n^o 18_suppl (20 juin 2006) : 10616. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.10616.

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10616 Iron is required for the activity of ribonucleotide reductase and synthesis of DNA. Cellular surface transferrin receptors (TfR) are the principal transport protein for iron into cells. It has been reported that inhibition of TfR gene expression leads to the suppression of tumor cell growth in cell culture. In the present study, an antisense oligonucleotide targeted to the transferrin receptor gene was used to treat 4T1 mammary adenocarinoma in cell culture and a mouse model. The cytotoxicity of a 24-mer TfR antisense oligonucleotide was determined by 3[H]-thymidine incorporation in vitro. The sense and random sequence 24-mer oligonucleotides were used as controls. We found that TfR antisense inhibited mRNA expression of TfR and cell growth of the 4T1 cells in the dose-dependent manner. Mice bearing the 4T1 mammary adenocarcinoma were continuously treated for 14 days through subcutaneous implantation of Alzet osmotic mini-pumps. Tumor sizes were measured twice a week. Tumor necrosis and metastases were determined grossly at autopsy and by microscopy. Tumor metastases to lungs (all lung lobes) was scored by the following criteria: 0 = no metastasis, 1 = 1–2 foci/slide, 2 = 3–10 foci/slide, 3 = 11–20 foci/slide and 4 = >20 foci/slide. At 4, 7 and 10 days post-treatment, tumor sizes of the TfR antisense-treated group were significant smaller than control mice (p < 0.05, p < 0.05 and p < 0.05, respectively). At 14 days post-treatment, autopsy showed that 91.7% (11/12) of control mice had multiple metastatic foci on their lung surfaces, but only 16.7% (2/12) of TfR antisense-treated mice had metastatic tumor foci on their lung surfaces (p < 0.001). Primary tumor did not have significant necrosis in either group. Mean lung metastasis scores of 3.25 ± 1.06 in control group vs. 1.75 ± 1.49 in TfR antisense-treated group (p < 0.01) were determined by microscopy. In summary, TfR antisense inhibited cell growth in cell culture and primary tumor growth in mice, and reduced lung metastasis of the 4T1 mouse mammary adenocarcinoma. No significant financial relationships to disclose.

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Topman-Rakover, Shiri, Einav Malach, Saul Burdman et Zvi Hayouka. « Antibacterial lipo-random peptide mixtures exhibit high selectivity and synergistic interactions ». Chemical Communications 56, n^o 80 (2020) : 12053–56. http://dx.doi.org/10.1039/d0cc04493h.

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We report antimicrobial activity of 5-mer lipo-random peptide mixtures (lipo-RPMs) composed of l-Phe, d-Lys and palmitic acid. Synergistic interactions were detected between selected lipopeptides that compose the lipo-RPM mixture.

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Pagano, Bruno, Carlo A. Mattia, Luigi Cavallo, Seiichi Uesugi, Concetta Giancola et Franca Fraternali. « Stability and Cations Coordination of DNA and RNA 14-Mer G-Quadruplexes : A Multiscale Computational Approach ». Journal of Physical Chemistry B 112, n^o 38 (25 septembre 2008) : 12115–23. http://dx.doi.org/10.1021/jp804036j.

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Wang, Yimin, Xinchuan Huang, Benjamin C. Shepler, Bastiaan J. Braams et Joel M. Bowman. « Flexible, ab initio potential, and dipole moment surfaces for water. I. Tests and applications for clusters up to the 22-mer ». Journal of Chemical Physics 134, n^o 9 (7 mars 2011) : 094509. http://dx.doi.org/10.1063/1.3554905.

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Lu, Pengfei, et Makoto Ando. « Uniform surface-to-line integral reduction of physical optics for curved surfaces by Keller-type equivalent edge currents in MER : Behaviors of fields on reflection shadow boundary ». Radio Science 49, n^o 5 (mai 2014) : 330–40. http://dx.doi.org/10.1002/2013rs005287.

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Zhu, Huaqun, Xiaolin Sun, Lei Zhu, Fanlei Hu, Lianjie Shi, Zhanguo Li et Yin Su. « The Expression and Clinical Significance of Different Forms of Mer Receptor Tyrosine Kinase in Systemic Lupus Erythematosus ». Journal of Immunology Research 2014 (2014) : 1–12. http://dx.doi.org/10.1155/2014/431896.

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Objective. To investigate the expression and clinical significance of trans-membrane MerTK (mMer) on circulating CD14+ monocytes/macrophages and soluble MerTK (sMer) levels in plasma in systemic lupus erythematosus (SLE).Method. 108 SLE patients and 42 healthy controls were recruited in this study. The expression of mMer on the surfaces of CD14+ monocytes/macrophages was evaluated by flow cytometry (FCM). The sMer levels were measured by ELISA. Real-time quantitative PCR was applied to evaluate the mRNA levels of MerTK and ADAM17.Results. Both mMer expression on CD14+ monocytes/macrophages and sMer levels in plasma significantly increased in SLE patients compared to healthy subjects. The frequency of anti-inflammatory MerTK expressing CD14+CD16+ monocytes decreased in SLE. mMer expression was positively correlated with CD163 expression on CD14+ cells. Both the mMer expression on CD14+ monocytes/macrophages and sMer levels in plasma were positively correlated with SLEDAI. Furthermore, more elevated mMer and sMer levels were found in patients with higher SLEDAI, presence of anti-SSA, anti-Sm autoantibodies, and lupus nephritis.Conclusion. Both mMer and sMer levels significantly increased in SLE and positively correlated with disease activity and severity. The upregulation of MerTK expression may serve as a biomarker of the disease activity and severity of SLE.

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Radcliffe, Scott, Meredith Sutzko, Zheng Jiang, Denise Freitag, Christy Swoboda, Lukas Frank et Adrian Rogers. « Validation of the AgraStrip® Gluten G12 Test Kit ». Journal of AOAC INTERNATIONAL 97, n^o 6 (1 novembre 2014) : 1638–50. http://dx.doi.org/10.5740/jaoacint.14-143.

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Abstract Romer Labs®, Inc. developed an immunochromatographic lateral flow assay for the qualitative detection of gluten in raw ingredients, processed foods, finished food products, and environmental surfaces, using the G12 antibody developed by Belén Morón. The G12 antibody targets a 33-mer peptide which is resistant to enzymatic digestion and heat denaturation, as well as being the fragment of the gliadin protein to which celiac disease sufferers react, making it a reliable analytical marker. This study was performed to validate the AgraStrip® Gluten G12 assay method under the guidance of the AOAC Performance Tested MethodsSM (PTM) program against AOAC Official Method of AnalysisSM2012.01 in rice flour, bread, cookie, ice cream, and chocolate matrixes spiked with either purified gliadin or wheat gluten standard at 0, 3, 8, 15, and 25 ppm concentrations and tested at the 5, 10, and 20 ppm assay thresholds, as well as on environmental surfaces. Stability, robustness, variation, and lot consistency studies were performed by spiking wheat gluten into a rice flour matrix at 0 and 15 ppm concentrations. The AgraStrip Gluten G12 assay was rigorously evaluated during this study and demonstrates its suitability as an AOAC PTM-certified gluten detection method.

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de Oliveira-Júnior, Luiz Carlos, Fabiana de Almeida Araújo Santos, Luiz Ricardo Goulart et Carlos Ueira-Vieira. « Epitope Fingerprinting for Recognition of the Polyclonal Serum Autoantibodies of Alzheimer’s Disease ». BioMed Research International 2015 (2015) : 1–8. http://dx.doi.org/10.1155/2015/267989.

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Autoantibodies (aAb) associated with Alzheimer’s disease (AD) have not been sufficiently characterized and their exact involvement is undefined. The use of information technology and computerized analysis with phage display technology was used, in the present research, to map the epitope of putative self-antigens in AD patients. A 12-mer random peptide library, displayed on M13 phages, was screened using IgG from AD patients with two repetitions. Seventy-one peptides were isolated; however, only 10 were positive using the Elisa assay technique (Elisa Index > 1). The results showed that the epitope regions of the immunoreactive peptides, identified by phage display analysis, were on the exposed surfaces of the proteins. The putative antigens MAST1, Enah, MAO-A, X11/MINT1, HGF, SNX14, ARHGAP 11A, APC, and CENTG3, which have been associated with AD or have functions in neural tissue, may indicate possible therapeutic targets.

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Pham, Hoang Lan, Da Hyun Yang, Woo Ri Chae, Jong Hyeok Jung, Thi Xoan Hoang, Nae Yoon Lee et Jae Young Kim. « PDMS Micropatterns Coated with PDA and RGD Induce a Regulatory Macrophage-like Phenotype ». Micromachines 14, n^o 3 (17 mars 2023) : 673. http://dx.doi.org/10.3390/mi14030673.

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Regulatory macrophages (Mreg) are a special cell type that present a potential therapeutic strategy for various inflammatory diseases. In vitro, Mreg generation mainly takes 7–10 days of treatment with chemicals, including cytokines. In the present study, we established a new approach for Mreg generation using a three-dimensional (3D) micropatterned polydimethylsiloxane (PDMS) surface coated with a natural biopolymer adhesive polydopamine (PDA) and the common cell adhesion peptide motif arginylglycylaspartic acid (RGD). The 3D PDMS surfaces were fabricated by photolithography and soft lithography techniques and were subsequently coated with an RGD+PDA mixture to form a surface that facilitates cell adhesion. Human monocytes (THP-1 cells) were cultured on different types of 2D or 3D micropatterns for four days, and the cell morphology, elongation, and Mreg marker expression were assessed using microscopic and flow cytometric analyses. The cells grown on the PDA+RGD-coated 3D micropatterns (20-µm width/20-µm space) exhibited the most elongated morphology and strongest expression levels of Mreg markers, such as CD163, CD206, CD209, CD274, MER-TK, TREM2, and DHRS9. The present study demonstrated that PDA+RGD-coated 3D PDMS micropatterns successfully induced Mreg-like cells from THP-1 cells within four days without the use of cytokines, suggesting a time- and cost-effective method to generate Mreg-like cells in vitro.

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Jabłońska-Wawrzycka, Agnieszka, Patrycja Rogala, Grzegorz Czerwonka, Katarzyna Gałczyńska, Marcin Drabik et Magdalena Dańczuk. « Ruthenium Complexes with 2-Pyridin-2-yl-1H-benzimidazole as Potential Antimicrobial Agents : Correlation between Chemical Properties and Anti-Biofilm Effects ». International Journal of Molecular Sciences 22, n^o 18 (18 septembre 2021) : 10113. http://dx.doi.org/10.3390/ijms221810113.

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Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2′-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.

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Tatareau, J. C., G. Lalaus, J. Pensedent Erblon, Elie Shitalou, P. Milhet, Nicolas Barré et Gérard Matheron. « L'élevage des petits ruminants en Martinique, Guadeloupe et Guyane : situation actuelle ». Revue d’élevage et de médecine vétérinaire des pays tropicaux 44, special (1 mai 1991) : 5–10. http://dx.doi.org/10.19182/remvt.9244.

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Les petits ruminants représentent 57000 têtes en Martinique, 30000 en Guadeloupe et un millier en Guyane, répartis en unités inférieures, en moyenne, à 10 têtes par exploitation. Les ovins sont les mieux représentés en Martinique alors qu'ils sont numériquement équivalents aux caprins dans les dépendances de Guadeloupe et en Guyane. Ils sont de races rustiques, prolifiques et bien adaptées au milieu : Créole, Black-Belly et St Martin. Les caprins, de race Créole dominent largement en Guadeloupe où ils bénéficient d'une bonne image de marque auprès des consommateurs et où, à la différence des ovins en Martinique, ils sont peu concurrencés par les importations de viande congelée. L'élevage, mené le plus souvent selon un mode traditionnel par des exploitants pluriactifs disposant de petites surfaces, et réticents à l'introduction d'innovations techniques, doit cependant pouvoir s'adapter aux nouvelles contraintes du marché et bénéficier de l'essor touristique et économique de ces départements d'outre mer.

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Chin, Andrea, Jing Liu, Theodore Jardetzky, David C. Johnson et Adam Vanarsdall. « Identification of functionally important domains of human cytomegalovirus gO that act after trimer binding to receptors ». PLOS Pathogens 18, n^o 4 (22 avril 2022) : e1010452. http://dx.doi.org/10.1371/journal.ppat.1010452.

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Human cytomegalovirus (HCMV) entry involves trimer (gH/gL/gO) that interacts with PDGFRα in fibroblasts. Entry into epithelial and endothelial cells requires trimer, which binds unidentified receptors, and pentamer (gH/gL/UL128-131), which binds neuropilin-2. To identify functionally important domains in trimer, we screened an overlapping 20-mer gO peptide library and identified two sets of peptides: 19/20 (a.a. 235–267) and 32/33 (a.a. 404–436) that could block virus entry. Soluble trimer containing wild type gO blocked HCMV entry, whereas soluble trimers with the 19/20 or 32/33 sequences mutated did not block entry. Interestingly, the mutant trimers retained the capacity to bind to cellular receptors including PDGFRα. Peptide 19/20 and 32/33 sequences formed a lobe extending from the surface of gO and an adjacent concave structure, respectively. Neither of these sets of sequences contacted PDGFRα. Instead, our data support a model in which the 19/20 and 32/33 trimer sequences function downstream of receptor binding, e.g. trafficking of HCMV into endosomes or binding to gB for entry fusion. We also screened for peptides that bound antibodies (Abs) in human sera, observing that peptides 20 and 26 bound Abs. These peptides engendered neutralizing Abs (NAbs) after immunization of rabbits and could pull out NAbs from human sera. Peptides 20 and 26 sequences represent the first NAb epitopes identified in trimer. These studies describe two important surfaces on gO defined by: i) peptides 19/20 and 32/33, which apparently act downstream of receptor binding and ii) peptide 26 that interacts with PDGFRα. Both these surfaces are targets of NAbs.

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Caro, A., V. Humblot, M. Minier, M. Salmain, C. Compère et C. M. Pradier. « Fonctionnalisation de surfaces d'acier inoxydable par des enzymes en vue d'inhiber l'adhésion de bactéries et la formation de biofilms en eau de mer ». Matériaux & ; Techniques 94 (2006) : 455–65. http://dx.doi.org/10.1051/mattech:2007020.

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Michaud, Yves, et Jean-Claude Dionne. « Altération des substrats rocheux et rôle du soulèvement gélival dans la formation des champs de blocaille, en Hudsonie ». Géographie physique et Quaternaire 41, n^o 1 (18 décembre 2007) : 7–18. http://dx.doi.org/10.7202/032661ar.

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RÉSUMÉ Depuis la déglaciation (7500 ans BP) et le retrait de la mer de Tyrrell, les cuestas hudsoniennes sont soumises aux agents d'érosion périglaciaires. Les surfaces rocheuses composées principalement de basalte, de dolomie et d'arkose, montrent, en moyenne, un pourcentage d'altération de 27%. Bien que la gélifraction soit le processus dominant, le soulèvement gélival a retenu l'attention en raison de son originalité et de son intensité. Ce mécanisme responsable de la formation des soulèvements rocheux périglaciaires joue aussi un rôle important dans la formation de champs de biocaille. Dans le secteur du golfe de Guillaume-Delisie, dans une aire de 16 km2, plus de 1800 édifices de soulèvement gélival ont été observés, ce qui donne, en moyenne, 110 soulèvements/km2. Les formes d'éjection ont été regroupées en quatre grandes catégories: monolithes, monticules, chaos et édifices à dépression centrale. Le volume de débris impliqués dans les soulèvements est important. Il concourt à la destruction des substrats rocheux au même titre que la gélifraction et la gélidisjonction. Dans le secteur étudié, plus de 25 000 m2 de surface rocheuse ont été détruits par le soulèvement gélival depuis la déglaciation. Comme les fragments éjectés demeurent sur place, il en résulte des champs de blocaille. La manifestation du phénomène requiert une surface rocheuse abondamment fissurée et saturée en eau ainsi que l'existence de cycles gel-dégel de grande amplitude. Le pergélisol jouerait aussi un rôle dans leur formation.

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Highlander, Sarah K., Jason M. Wood, John D. Gillece, Megan Folkerts, Viacheslav Fofanov, Tara Furstenau, Nitin K. Singh et al. « Multi-faceted metagenomic analysis of spacecraft associated surfaces reveal planetary protection relevant microbial composition ». PLOS ONE 18, n^o 3 (22 mars 2023) : e0282428. http://dx.doi.org/10.1371/journal.pone.0282428.

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The National Aeronautics and Space Administration (NASA) has been monitoring the microbial burden of spacecraft since the 1970’s Viking missions. Originally culture-based and then focused 16S sequencing techniques were used, but we have now applied whole metagenomic sequencing to a variety of cleanroom samples at the Jet Propulsion Lab (JPL), including the Spacecraft Assembly Facility (SAF) with the goals of taxonomic identification and for functional assignment. Our samples included facility pre-filters, cleanroom vacuum debris, and surface wipes. The taxonomic composition was carried out by three different analysis tools to contrast marker, k-mer, and true alignment approaches. Hierarchical clustering analysis of the data separated vacuum particles from other SAF DNA samples. Vacuum particle samples were the most diverse while DNA samples from the ISO (International Standards Organization) compliant facilities and the SAF were the least diverse; all three were dominated by Proteobacteria. Wipe samples had higher diversity and were predominated by Actinobacteria, including human commensals Cutibacterium acnes and Corynebacterium spp. Taxa identified by the three methods were not identical, supporting the use of multiple methods for metagenome characterization. Likewise, functional annotation was performed using multiple methods. Vacuum particles and SAF samples contained strong signals of the tricarboxylic acid cycle and of amino acid biosynthesis, suggesting that many of the identified microorganisms have the ability to grow in nutrient-limited environments. In total, 18 samples generated high quality metagenome assembled genomes (MAG), which were dominated by Moraxella osloensis or Malassezia restricta. One M. osloensis MAG was assembled into a single circular scaffold and gene annotated. This study includes a rigorous quantitative determination of microbial loads and a qualitative dissection of microbial composition. Assembly of multiple specimens led to greater confidence for the identification of particular species and their predicted functional roles.

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Francés-Monerris, Antonio, Kevin Magra, Mohamed Darari, Cristina Cebrián, Marc Beley, Edoardo Domenichini, Stefan Haacke et al. « Synthesis and Computational Study of a Pyridylcarbene Fe(II) Complex : Unexpected Effects of fac/mer Isomerism in Metal-to-Ligand Triplet Potential Energy Surfaces ». Inorganic Chemistry 57, n^o 16 (31 juillet 2018) : 10431–41. http://dx.doi.org/10.1021/acs.inorgchem.8b01695.

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Palmer, Bentley J., et Ross H. Hill. « Solid state photochemistry of fac-Co(NH3)3(NO2)3 and mer-Co(NH3)3(N3)3 as thin films on Si(111) surfaces ». Journal of Photochemistry and Photobiology A : Chemistry 72, n^o 3 (juin 1993) : 243–49. http://dx.doi.org/10.1016/1010-6030(93)80020-a.

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Morozov, I. A. « Kinetics of atomic force microscope probe interaction with inhomogeneous polymer surface in fast nano-indentation regime ». Вестник Пермского университета. Физика, n^o 4 (2021) : 21–29. http://dx.doi.org/10.17072/1994-3598-2021-4-21-29.

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Atomic force microscopy (AFM) is a powerful tool for studying the structural and physical-mechanical properties of surfaces. The AFM experiment consists in detecting the interaction be-tween the probe and the material. The probe is an elastic cantilever fixed horizontally at one end; a tip is located at the free end of the cantilever. The interaction of the tip with the surface causes de-flection of the cantilever, which is interpreted depending on the experimental conditions. High-speed indentation atomic force microscopy methods allow obtaining maps of three-dimensional re-lief and physical-mechanical properties of the material in high resolution at micro- and nanoscale levels. In this case, the probe is rapidly pressed on the material and the interaction is recorded at each point of the surface of the studied area. The user sets the speed at which the probe approaches the material surface. This value is assumed to be constant and is called the indentation rate. How-ever, this is not true: the tip speed at the loose end of the cantilever depends in general on many factors. As an example of investigation of polyurethane surface (heterogeneous two-phase poly-mer) it is shown that the probe-material interaction speed nonlinearly depends on the surface area, indentation depth and direction, nominal speed of experiment, cantilever properties. This affects the measurement of relief topography, stiffness, Van der Waals forces and adhesion between the probe and the material. Thus, for a correct quantitative interpretation of the results, the interaction speed of the tip with the material must be taken into account; this statement is especially important when working with soft polymers. The presented methods can be useful in the study of a wide class of soft heterogeneous materials.

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COURAULT, Dominique, Gilles BELAUD, Valérie DEMAREZ, Nicolas BAGHDADI et Jean-Stéphane BAILLY. « Contribution de la télédétection pour caractériser les zones irriguées et les prélèvements d'eau pour l'irrigation ». Sciences Eaux & ; Territoires, n^o 45 (11 octobre 2024) : 8143. http://dx.doi.org/10.20870/revue-set.2024.45.8143.

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La télédétection, en offrant une couverture spatiale et temporelle étendue, permet une meilleure compréhension des besoins en eau des cultures. Actuellement, diverses variables liées à l'eau sont en libre accès, permettant de suivre les types de cultures, l'humidité des sols, et la dynamique des couverts végétaux. Cependant, les cartes annuelles des zones irriguées manquent encore, bien que des méthodes prometteuses soient en développement. Les estimations des dates d'irrigation et des volumes d'eau apportés restent également en phase de recherche. Les sections développées dans cet article décrivent des avancées sur ces points. Les images satellitaires, comme celles délivrées sur la plateforme THEIA, fournissent des mises à jour régulières des cartes des cultures, identifiant 24 classes en France et outre-mer. D'ici 2026, des projets visent à améliorer la fréquence et la précision de ces cartes. Pour les surfaces irriguées, l'utilisation d'indices de végétation et de données radar permet de distinguer les cultures irriguées des non-irriguées, avec une précision variable. Enfin, des approches combinant télédétection et modèles agro-hydrologiques montrent un potentiel significatif pour la gestion de l'eau agricole, malgré des défis persistants.

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Mummert, Mark E., Mansour Mohamadzadeh, Diana I. Mummert, Norikatsu Mizumoto et Akira Takashima. « Development of a Peptide Inhibitor of Hyaluronan-Mediated Leukocyte Trafficking ». Journal of Experimental Medicine 192, n^o 6 (11 septembre 2000) : 769–80. http://dx.doi.org/10.1084/jem.192.6.769.

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Hyaluronan (HA), a high molecular weight glycosaminoglycan, is expressed abundantly in the extracellular matrix and on cell surfaces. Although HA is known to bind many adhesion molecules, little information has been available with respect to its direct physiological role. In this study, we developed a novel 12-mer (GAHWQFNALTVR) peptide inhibitor of HA, termed “Pep-1,” by using phage display technology. Pep-1 showed specific binding to soluble, immobilized, and cell-associated forms of HA, and it inhibited leukocyte adhesion to HA substrates almost completely. Systemic, local, or topical administration of Pep-1 inhibited the expression of contact hypersensitivity responses in mice by blocking skin-directed homing of inflammatory leukocytes. Pep-1 also inhibited the sensitization phase by blocking hapten-triggered migration of Langerhans cells from the epidermis. These observations document that HA plays an essential role in “two-way” trafficking of leukocytes to and from an inflamed tissue, and thus provide technical and conceptual bases for testing the potential efficacy of HA inhibitors (e.g., Pep-1) for inflammatory disorders.

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Anne, Agnès, et Christophe Demaille. « Electron Transport by Molecular Motion of redox-DNA Strands : Unexpectedly Slow Rotational Dynamics of 20-mer ds-DNA Chains End-Grafted onto Surfaces via C6Linkers ». Journal of the American Chemical Society 130, n^o 30 (juillet 2008) : 9812–23. http://dx.doi.org/10.1021/ja801074m.

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Clet, Martine, et Serge Occhietti. « La sous-séquence des sédiments de Saint-Pierre — rythmites du Saint-Maurice — Sables des Vieilles-Forges, Pléistocène supérieur, vallée du Saint-Laurent, Québec ». Géographie physique et Quaternaire 50, n^o 3 (30 novembre 2007) : 287–310. http://dx.doi.org/10.7202/033101ar.

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RÉSUMÉLe Quaternaire de la vallée et de l'estuaire moyen du Saint-Laurent est caractérisé par des séquences sédimentaires emboîtées. La séquence supérieure est la mieux représentée. Elle comprend des dépôts non glaciaires inférieurs, associés notamment à l'Interstade des Becquets, le Till wisconsinien de Gentilly et les sédiments des mers de Champlain et de Goldthwait. La base de cette séquence est emboîtée dans l'Argile de La Pérade (Mer de Cartier, Sangamonien supérieur) dont le contenu pollinique témoigne de la recolonisation végétale des surfaces déglacées et d'un bref épisode de réchauffement avant l'implantation de la forêt boréale. Au-dessus de la surface d'emboîtement, les Sédiments fluviatiles de Saint-Pierre ont un contenu pollinique qui indique le maintien d'une forêt boréale. Les Rythmites du Saint-Maurice, sus-jacentes, représentent au moins 1000 ans de sédimentation dans le Lac de La Vérendrye. Le contenu pollinique et les macrorestes de la zone inférieure de ces rythmites indiquent l'inondation, dans les basses terres, d'une sapinière associée à des essences thermophiles plus abondantes que dans les sédiments fluviatiles antérieurs. La zone supérieure évoque le retour à une pessière avec diminution des espèces thermophiles. Au-dessus, les Sables des Vieilles-Forges comprennent trois lithozones : sable fin lacustre, sable deltaïque et dépôts proglaciaires. Leur contenu pollinique témoigne de la détérioration du climat : la forêt boréale à Picea évolue progressivement vers une toundra forestière. Les zones supérieures sont stériles. Cette palynostratigraphie permet d'établir des corrélations entre les différents sites répartis sur plus de 400 km dans la vallée du Saint-Laurent et de différencier des unités et des séquences qui semblaient similaires.

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Mogi, Iwao, Ryoichi Morimoto, Ryoichi Aogaki et Kohki Takahashi. « Effects of Vertical Magnetohydrodynamic Flows on Chiral Surface Formation in Magnetoelectrolysis ». Magnetochemistry 4, n^o 3 (6 septembre 2018) : 40. http://dx.doi.org/10.3390/magnetochemistry4030040.

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Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce chiral surfaces. This paper shows the effects of vertical MHD flow on the chiral surface formation in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. To control the vertical MHD flows the working electrode was embedded in a tube wall with various heights of 2–12 mm, and the vertical MHD flows were expected to penetrate into the tubes with damping. In both MED and MEE experiments, the surface chirality diminished considerably at the wall height of 12 mm. When the penetrating MHD flow could not reach the electrode surface in the sufficiently tall wall, such an MHD flow could not affect the micro-MHD vortices. These results demonstrate that the vertical MHD flow plays a significant role in symmetry breaking of micro-MHD vortices.

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Lai, D. Y. F., N. T. Roulet, E. R. Humphreys, T. R. Moore et M. Dalva. « The effect of atmospheric turbulence and chamber deployment period on autochamber CO<sub>2</sub> ; and CH<sub>4</sub> ; flux measurements in an ombrotrophic peatland ». Biogeosciences Discussions 9, n^o 2 (1 février 2012) : 1439–82. http://dx.doi.org/10.5194/bgd-9-1439-2012.

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Abstract. Accurate quantification of soil-atmosphere gas exchange is essential for understanding the magnitude and controls of greenhouse gas emissions. We used an automatic closed dynamic chamber system to measure the fluxes of CO2 and CH4 for several years at the ombrotrophic Mer Bleue peatland near Ottawa, Canada and found that atmospheric turbulence and chamber deployment period had a considerable influence on the observed flux rates. With a short deployment period of 2.5 min, CH4 flux exhibited strong diel patterns and both CH4 and nighttime CO2 effluxes were highly and negatively correlated with friction velocity as were the CO2 concentration gradients in the top 20 cm of peat. This suggests winds were flushing the very porous and relatively dry near surface peat layers, altering the concentration gradient and resulting in a 9 to 57% underestimate of CH4 flux at any time of day and a 13 to 21% underestimate of nighttime CO2 fluxes in highly turbulent conditions. Conversely, there was evidence of an overestimation of ~100% of CH4 and nighttime CO2 effluxes in calm atmospheric conditions possibly due to enhanced near-surface gas concentration gradient by mixing of chamber headspace air by fans. These problems were resolved by extending the deployment period to 30 min. After 13 min of chamber closure, the flux rate of CH4 and nighttime CO2 became constant and were not affected by turbulence thereafter, yielding a reliable estimate of the net biological fluxes. The measurement biases we observed likely exist to some extent in all chamber flux measurements made on porous and aerated substrate, such as peatlands, organic soils in tundra and forests, and snow-covered surfaces, but would be difficult to detect unless high frequency, semi-continuous observations are made.

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Newcombe, David A., Myron T. La Duc, Parag Vaishampayan et Kasthuri Venkateswaran. « Impact of assembly, testing and launch operations on the airborne bacterial diversity within a spacecraft assembly facility clean-room ». International Journal of Astrobiology 7, n^o 3-4 (19 septembre 2008) : 223–36. http://dx.doi.org/10.1017/s1473550408004254.

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AbstractIn an effort to minimize the probability of forward contamination of pristine extraterrestrial environments, the National Aeronautics and Space Administration requires that all US robotic spacecraft undergo assembly, testing and launch operations (ATLO) in controlled clean-room environments. This study examines the impact of ATLO activity on the microbial diversity and overall bioburden contained within the air of the clean-room facility in which the Mars Exploration Rovers (MERs) underwent final preparations for launch. Air samples were collected from several facility locations and traditional culture-based and molecular methodologies were used to measure microbial burden and diversity. Surprisingly, the greatest estimates of airborne bioburden, as derived from ATP content and cultivation assays, were observed prior to the commencement of MER ATLO activities. Furthermore, airborne microbial diversity gradually declined from the initiation of ATLO on through to launch. Proteobacterial sequences were common in 16S rDNA clone libraries. Conspicuously absent were members of the Firmicutes phylum, which includes the genusBacillus. In previous studies, species of this genus were repeatedly isolated from the surfaces of spacecraft and clean-room assembly facilities. Increased cleaning and maintenance initiated immediately prior to the start of ATLO activity could explain the observed declines in both airborne bioburden and microbial diversity.

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