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  • 1
    Electronic Resource
    Electronic Resource
    Species-specificity of the cohesin-dockerin interaction between Clostridium thermocellum and Clostridium cellulolyticum: Prediction of specificity determinants of the dockerin domain (1997)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 29 (1997), S. 517-527 
    Details
    ISSN: 0887-3585
    Keywords: cellulosome ; cellulases ; cohesin domain ; scaffoldin subunit ; EF-hand motif ; molecular modeling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cross-species specificity of the cohesin-dockerin interaction, which defines the incorporation of the enzymatic subunits into the cellulosome complex, has been investigated. Cohesin-containing segments from the cellulosomes of two different species, Clostridium thermocellum and Clostridium cellulolyticum, were allowed to interact with cellulosomal (dockerin-containing) enzymes from each species. In both cases, the cohesin domain of one bacterium interacted with enzymes from its own cellulosome in a calcium-dependent manner, but the same cohesin failed to recognize enzymes from the other species. Thus, in the case of these two bacteria, the cohesin-dockerin interaction seems to be species-specific. Based on intra- and cross-species sequence comparisons among the different dockerins together with their known specificities, we tender a prediction as to the amino-acid residues critical to recognition of the cohesins. The suspected residues were narrowed down to only four, which comprise a repeated pair located within the calcium-binding motif of two duplicated sequences, characteristic of the dockerin domain. According to the proposed model, these four residues do not participate in the binding of calcium per se; instead, they appear to serve as recognition codes in promoting interaction with the cohesin surface. Proteins 29:517-527, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Thermogravimetric analysis of polystyrene: Influence of sample weight and heating rate on thermal and kinetic parameters (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 187-197 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This article studies the influence of the heating rate and sample weight on the thermal decomposition of polystyrene (first-order kinetics). For this purpose, the kinetic parameters (i.e., frequency factor and activation energy), variables at the maximum decomposition rate (such as conversion, reaction rate, and temperature), as well as some characteristic temperatures have been determined for a series of experiments where the heating rate varies (0.5-11.5 K/min) and also, the sample weight (6.0-25.1 mg). Some mathematical equations have been developed that allow: (1) evaluation of the activation energy of thermal decomposition by different ways and comparing the results obtained; (2) relating different parameters between themselves, such as the heating rate with the temperature at the maximum decomposition rate or the frequency factor with the heating rate and sample weight. Finally, some theoretical explanations of the variation of thermal and kinetic parameters have been proposed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of the crosslinking degree on curing kinetics of an epoxy-anhydride systemThis article was presented during the 6th European Symposium on Thermal Analysis and Calorimetry held in Grado, Italy, September 11-16, 1994. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 1413-1421 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The cure kinetics of a diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin with methyltetrahydrophthalic anhydride and an accelerator was studied by nonisothermal DSC data. The systems were uncured resin and partially cured with the following extents of cure measured by the residual heat method (αDSC): 0.37, 0.63, 0.81, and 0.90. The activation energy calculated by the Kissinger method increases from 63 kJ/mol for the uncured epoxy to 77 kJ/mol for the partially cured with αDSC = 0.90. Additionally, the activation energy calculated by the isoconversional method shows a dependence on the conversion degree α. The activation energy tends to decreases initially with the conversion degree, possibly due to the autocatalytic effect; then, it passes through a minimum about α = 0.4 and, finally, increases slightly due to the increase of crosslinks which reduce the mobility of the unreacted groups. A simple, consistent method of kinetic analysis was applied. This method enables one to select the most convenient model and the calculation of kinetic parameters. A two-parameter (m, n) autocatalytic model (S̆esták-Berggren equation) was found to be the most convenient model to study the curing of epoxy systems. The results show a dependence of the kinetic parameters on the initial degree of crosslinking of the partially cured epoxy. The exponent m tends to decrease with the extent of cure, while the exponent n remains practically invariable. These results show a change of the kinetic when the initial extent of cure of the epoxy system increases. The In A data, A being the preexponenetial factor in the Arrhenius dependence of the temperature on the rate of conversion, increase with the extent of cure, showing a correlation with the calculated activation energy values. The nonisothermal DSC curves theoretically calculated show a very good agreement with the experimental data. The two-parameter (m, n) autocatalytic model gives a good description of the curing kinetics of epoxy resins with different extents of cure. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070561104
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  • 4
    Electronic Resource
    Electronic Resource
    FTIR and DSC study of HDPE structural changes and mechanical properties variation when exposed to weathering aging during canadian winter (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 153-159 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The aging of high-density polyethylene (HDPE) when exposed to drastic climatic conditions (Canadian winter, characterized by low temperature and abrupt temperature variations between the night and the day) was studied. The importance of degradation was determined by evaluating the microstructural changes in HDPE (i.e., oxidations, ramifications, and polymeric chain breaking) by means of FTIR spectrophotometry. The crystallinity variation in HDPE by FTIR and DSC was also studied. Both techniques led to coherent results: there was a loss of crystallinity due to weathering degradation. This crystallinity reduction produced a drastic decrease in impact energy. However, the other properties evaluated were not significantly affected. © 1996 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
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    Ocean acidification reduces feeding rates in the scleractinian coral Stylophora pistillata (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-01-04
    Description: A general decline in coral calcification has been observed in response to ocean acidification. It has recently been shown that heterotrophic feeding (the acquisition of organic nutrients) enables one massive coral species to maintain its calcification rates while exposed to ocean acidification but the consequences of higher seawater partial pressure of CO 2 ( ) on coral feeding capacities themselves have never been investigated. Exposing long-term acclimated starved and fed colonies of the major reef builder Stylophora pistillata to either ambient pH T (8.06 ± 0.05; 417 Pa ) or low pH T (7.51 ± 0.06; 1697 Pa ) showed that higher feeding rates can counterbalance the negative effects of seawater acidification on coral calcification. Indeed, relative to unfed corals under ambient pH T conditions, calcification rates in unfed corals decreased by 53.6% but remained constant in fed corals under high conditions. Results also clearly show that acidification affects the feeding capacity and feeding effort of the branching coral S. pistillata . Organic nutrient acquisition was severely reduced under high , with a simultaneous decrease in the dissolved free amino acid uptake rates, the alkaline phosphatase activities, and the feeding rates on Artemia salina nauplii. Considering that all these processes are needed to fulfill the nutrient needs of the symbiotic association, on a long-term basis, lower feeding rates will likely aggravate the already fragile physiological state of many corals under warmer, more acidic conditions.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
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  • 6
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    Vertical and Oblique ionospheric soundings over the long haul HF link between Antarctica and Spain (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-08-28
    Description: This paper presents a comparative study between the oblique sounding results, the ITU Rec533 HF prediction model and the vertical sounding results of a transequatorial long haul link. The long haul link is a 12760km link between the Spanish Antarctic Station, SAS, located in the Livingston Island and the Ebro Observatory (OE) in Spain. The data was collected during three consecutive surveys (2009/10, 2010/11 and 2011/12). The ionospheric channel from the SAS to the OE is studied in terms of frequency availability as function of time using the measurements of an oblique incidence sounder (OIS) and measurements of several vertical incidence sounding stations (VIS) placed near the estimated radiopropagation path. The results obtained show promising correlations between VIS and OIS measurements, and led us think that the frequency of largest availability for this particular long haul radio link can be estimated from the VIS sounding measurements.
    Print ISSN: 0048-6604
    Electronic ISSN: 1944-799X
    Topics: Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
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  • 7
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    Thermally tolerant corals have limited capacity to acclimatize to future warming (2014)
    Wiley-Blackwell
    Details
    Publication Date: 2014-03-12
    Description: Thermal stress affects organism performance differently depending on the ambient temperature to which they are acclimatized, which varies along latitudinal gradients. This study investigated whether differences in physiological responses to temperature are consistent with regional differences in temperature regimes for the stony coral Oculina patagonica . To resolve this question we experimentally assessed how colonies originating from four different locations characterized by 〉3°C variation in mean maximum annual temperature responded to warming from 20 to 32°C. We assessed plasticity in symbiont identity, density, and photosynthetic properties, together with changes in host tissue biomass. Results show that, without changes in the type of symbiont hosted by coral colonies, O. patagonica has limited capacity to acclimatize to future warming. We found little evidence of variation in overall thermal tolerance, or in thermal optima, in response to spatial variation in ambient temperature. Given that the invader O. patagonica is a relatively new member of the Mediterranean coral fauna our results also suggest that coral populations may need to remain isolated for a long period of time for thermal adaptation to potentially take place. Our study indicates that for O. patagonica , mortality associated with thermal stress manifests primarily through tissue breakdown under moderate but prolonged warming (which does not impair symbiont photosynthesis and, therefore, does not lead to bleaching). Consequently, projected global warming is likely to causes repeat incidents of partial and whole colony mortality and might drive a gradual range contraction of Mediterranean corals. This article is protected by copyright. All rights reserved.
    Print ISSN: 1354-1013
    Electronic ISSN: 1365-2486
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Published by Wiley-Blackwell
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  • 8
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    Psoriasis associated with idiopathic CD4+ T-cell lymphopenia: a regulatory T cells defect? (2014)
    Wiley-Blackwell
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    Publication Date: 2014-03-04
    Description: Idiopathic CD4 + lymphocytopenia (ICL) is a rare immunodeficiency syndrome of unknown origin for which the increased risks of opportunistic infections and of malignancies have been well established but skin dysimmune diseases, including psoriasis, have been scarcely reported to now. We report herein the severe course of psoriasis in 4 patients with ICL, and show evidence for a defect in the skin recruitment of regulatory CD4 + FoxP3 + T cells. These data raise the apparent paradigm of the occurrence of a severe immunomediated disease together with a profound T-cell defect, a model which might also apply to other immune deficiencies associated with psoriasis. This article is protected by copyright. All rights reserved.
    Print ISSN: 0007-0963
    Electronic ISSN: 1365-2133
    Topics: Medicine
    Published by Wiley-Blackwell
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  • 9
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    The effect of a centenary storm on the long-lived seagrass Posidonia oceanica (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-01-06
    Description: We used the disturbance resulting from a once in a 100-yr storm on the northwest Mediterranean coast to examine the extent of the disturbance, the tolerance thresholds to burial, and the medium-term response of the long-lived Posidonia oceanica seagrass. Sediment burial at 12 surveyed areas was particularly strong in shallow meadows, with 23% of their surfaces buried, on average, under more than 10 cm of sediment. In contrast, less than 5% of the meadow was affected at deeper locations. At three sites, we tracked short-term mortality along a gradient of sediment burial. Survival response to burial was clearly nonlinear, with a significant threshold at 4–5 cm, beyond which shoot mortality was 100%. To track medium-term potential recovery, we established permanent plots subject to three sediment burial levels (0–5, 5–10, and 〉 10 cm burial) in four meadows. Where the initial shoot mortality was 100%, we recorded no shoot recovery over the 4-yr period. In the remaining plots, where some shoots remained alive, we detected either further mortality or shoot recovery of 7% per year on average. Extreme storm events can result in sudden catastrophic losses of seagrass cover in shallow P. oceanica meadows. In the long term and due to the long return time of such storms, the species may still be able to recover despite its low recovery potential. However, added anthropogenic stressors, including climate change, may seriously test the ability of long-lived shallow seagrass ecosystems to resist high-intensity natural disturbances and may be critical for its persistence.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
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  • 10
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    Efficacy and safety of biologics in erythrodermic psoriasis: a multicentre, retrospective study (2012)
    Wiley-Blackwell
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    Publication Date: 2012-04-03
    Description: Background:  Even though efficacy of biologics has been extensively studied in psoriasis vulgaris, studies in erythrodermic psoriasis, the most severe form of the disease, have beenscarcelyreported. Objectives:  To address the efficacy and safety of biologics in patients with erythrodermic psoriasis. Methods:  A multicentre national retrospective study was performed using the French Psoriasis Group network. Patients showing psoriasis involving at least 90% of body surface area (BSA), and in whom severity of the disease had been evaluated before and after 3 and/or 6 months of treatment with biologics, were enrolled in the study. Results were expressed using intention to treat analysis. Results:  We included 28 patients, representing 42 flares of erythrodermic psoriasis treated with infliximab (n=24), adalimumab (7), etanercept (6), ustekinumab (3) or efalizumab (2). A 75% improvement of BSA or PASI index 12 to 14 weeks after treatment onset was reached in 48% of flares treated with infliximab, in 50% of those treated with adalimumab and in 40% of those treated with etanercept. Twelve serious adverse events consisting of bacterial infection in 7 of them were observed. Biological treatment was discontinued for safety concern in 19% of cases. A given biologic was pursued up to 48 weeks in 34% of flares. Conclusion:  Biologics show overall good short-term efficacy, but treatment switch due to lack of efficacy or side effects is frequently observed on a longer term, with one third of patients still receiving the drug after one year. The most significant safety concern consists of severe infections.
    Print ISSN: 0007-0963
    Electronic ISSN: 1365-2133
    Topics: Medicine
    Published by Wiley-Blackwell
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