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Gordon W. Duff - One of the best experts on this subject based on the ideXlab platform.
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The interleukin‐1 genotype as a Severity Factor in adult periodontal disease
Journal of clinical periodontology, 1997Co-Authors: Kenneth S. Kornman, Allison Crane, Hwa-ying Wang, Francesco S.di Giovlne, Michael G. Newman, Frederick W. Pirk, Thomas G. Wilson, Frank L. Higginbottom, Gordon W. DuffAbstract:Although specific bacteria, dental plaque, and age are associated with periodontal disease, there are currently no reliable predictors of periodontitis Severity. Studies in twins have suggested a genetic contribution to the pathogenesis of periodontitis, but previous attempts to identify genetic markers have been unsuccessful. The pro-inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis Factor alpha (TNF alpha) are key regulators of the host responses to microbial infection. IL-1 is also a major modulator of extracellular matrix catabolism and bone resorption. We report a specific genotype of the polymorphic IL-1 gene cluster that was associated with Severity of periodontitis in non-smokers, and distinguished individuals with severe periodontitis from those with mild disease (odds ratio 18.9 for ages 40-60 years). Functionally, the specific periodontitis-associated IL-1 genotype comprises a variant in the IL-1B gene that is associated with high levels of IL-1 production. In smokers severe disease was not correlated with genotype. In this study, 86.0% of the severe periodontitis patients were accounted for by either smoking or the IL-1 genotype. This study demonstrates that specific genetic markers, that have been associated with increased IL-1 production, are a strong indicator of susceptibility to severe periodontitis in adults.
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the interleukin 1 genotype as a Severity Factor in adult periodontal disease
Journal of Clinical Periodontology, 1997Co-Authors: Kenneth S. Kornman, Allison Crane, Hwa-ying Wang, Francesco S.di Giovlne, Michael G. Newman, Frederick W. Pirk, Thomas G. Wilson, Frank L. Higginbottom, Gordon W. DuffAbstract:Although specific bacteria, dental plaque, and age are associated with periodontal disease, there are currently no reliable predictors of periodontitis Severity. Studies in twins have suggested a genetic contribution to the pathogenesis of periodontitis, but previous attempts to identify genetic markers have been unsuccessful. The pro-inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis Factor alpha (TNF alpha) are key regulators of the host responses to microbial infection. IL-1 is also a major modulator of extracellular matrix catabolism and bone resorption. We report a specific genotype of the polymorphic IL-1 gene cluster that was associated with Severity of periodontitis in non-smokers, and distinguished individuals with severe periodontitis from those with mild disease (odds ratio 18.9 for ages 40-60 years). Functionally, the specific periodontitis-associated IL-1 genotype comprises a variant in the IL-1B gene that is associated with high levels of IL-1 production. In smokers severe disease was not correlated with genotype. In this study, 86.0% of the severe periodontitis patients were accounted for by either smoking or the IL-1 genotype. This study demonstrates that specific genetic markers, that have been associated with increased IL-1 production, are a strong indicator of susceptibility to severe periodontitis in adults.
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interleukin 1 receptor antagonist gene polymorphism as a disease Severity Factor in systemic lupus erythematosus
Arthritis & Rheumatism, 1994Co-Authors: Alexandra I. F. Blakemore, Joanna K. Tarlow, Michael J. Cork, Caroline Gordon, Paul Emery, Gordon W. DuffAbstract:Objective. We have previously described associations between an allele of the interleukin–1 receptor antagonist gene (IL1RN) and several inflammatory diseases. In this study we tested the IL1RN gene as a possible marker in patients with systemic lupus erythematosus (SLE). Methods. Eighty–one SLE patients and 261 ethnically matched control subjects were genotyped by polymerase chain reaction. Results. We found an increase in both frequency and carriage rate of IL1RN*2 in the SLE group. This association strengthened with extensive disease and particularly with the presence of photosensitivity and discoid skin lesions. Conclusion. We describe a novel association between IL1RN*2 and SLE. Carriage of the allele seems to influence Severity rather than susceptibility to SLE. We postulate that the association of this polymorphism with disease Severity is a widespread feature of common inflammatory and autoimmune diseases.
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Interleukin–1 receptor antagonist gene polymorphism as a disease Severity Factor in systemic lupus erythematosus
Arthritis and rheumatism, 1994Co-Authors: Alexandra I. F. Blakemore, Joanna K. Tarlow, Michael J. Cork, Caroline Gordon, Paul Emery, Gordon W. DuffAbstract:Objective. We have previously described associations between an allele of the interleukin–1 receptor antagonist gene (IL1RN) and several inflammatory diseases. In this study we tested the IL1RN gene as a possible marker in patients with systemic lupus erythematosus (SLE). Methods. Eighty–one SLE patients and 261 ethnically matched control subjects were genotyped by polymerase chain reaction. Results. We found an increase in both frequency and carriage rate of IL1RN*2 in the SLE group. This association strengthened with extensive disease and particularly with the presence of photosensitivity and discoid skin lesions. Conclusion. We describe a novel association between IL1RN*2 and SLE. Carriage of the allele seems to influence Severity rather than susceptibility to SLE. We postulate that the association of this polymorphism with disease Severity is a widespread feature of common inflammatory and autoimmune diseases.
Jean-michel Lavoie - One of the best experts on this subject based on the ideXlab platform.
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Steam explosion of sweet sorghum stems: Optimisation of the production of sugars by response surface methodology combined with the Severity Factor
Industrial Crops and Products, 2018Co-Authors: Jérémie Damay, Xavier Duret, Thierry Ghislain, Olivier Lalonde, Jean-michel LavoieAbstract:Abstract The purpose of this work is to determine the best conditions allowing the optimal recovery of the first and second generation sugars found in sweet sorghum. This optimization was performed using the Severity Factor, combined with response surface methodology (RSM) and based on a two-variable central composite design. Dry sorghum was first impregnated with water and then submitted to steam processes. Sugars were recovered in solution, both after the impregnation step and after the steam treatments. A central composite design and response surface methodology was applied to analyze the effects of the reaction time (2–8 min) and the temperature (200–220 °C) on the mass loss and sugar yields. Mass loss and different sugar yields were also correlated to the Severity Factor and compared to the RSM analysis. Similarly, the response surfaces and the isoresponse curves from the experimental design allowed understanding the mass loss as well as understanding several sugar yields according to the temperature and reaction time. The best operating conditions (i.e. for a Severity Factor of 3.6 or 2 min at 215 °C) allowed recovery of 37.3 wt% total sugars based on dry sorghum.
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Lignin extraction – Reassessment of the Severity Factor with respect to hydroxide concentration
Bioresource technology, 2014Co-Authors: Roland Lee, Véronique Berberi, Joey Labranche, Jean-michel LavoieAbstract:Steam processes have often been associated with a Severity Factor, correlating the cooking temperature, time and catalyst used in the process. Although equations for treatments with and without acid catalyst have been suggested, there is so far no simple equation allowing a precise estimation of the amount of lignin extracted from lignocellulosic biomass. In this work, a new version of the Severity Factor equation is proposed. This has been shown to correlate effectively to the amount of lignin extracted from various types of lignocellulosic materials and different extraction methods. The resulting Severity Factor is robust with potential to be utilized both for acid and base-catalyzed extraction of lignin. Finally, the proposed correlation between the Severity Factor and extracted lignin under base conditions has been correlated with empirical data to validate the entire model and especially under mild condition where lesser information was available from open literature.
Carlos Martín - One of the best experts on this subject based on the ideXlab platform.
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Effects of operational conditions on auto-catalyzed and sulfuric-acid-catalyzed hydrothermal pretreatment of sugarcane bagasse at different Severity Factor
Industrial Crops and Products, 2021Co-Authors: Dimitrios Ilanidis, Stefan Stagge, Leif J. Jönsson, Carlos MartínAbstract:Abstract Bagasse, a major by-product of sugarcane-processing industries, has potential to play a significant role as feedstock for production of cellulosic ethanol, platform chemicals, and bio-based commodities. Pretreatment is essential for efficient processing of lignocellulosic feedstocks by biochemical conversion. In this work, auto-catalyzed (A-HTP) and dilute sulfuric-acid-catalyzed (SA-HTP) hydrothermal pretreatment of sugarcane bagasse was investigated, setting the temperature (175−205 °C) and the time (4−51 min) in such a way that the Severity Factor (SF) was always maintained at one of three predetermined values (2.8, 3.8, and 4.8). The investigation covered the effects of different operational pretreatment conditions on (i) the formation of sugars and water-soluble bioconversion inhibitors, including newly discovered inhibitors such as formaldehyde and p-benzoquinone, in the pretreatment liquid, (ii) the chemical composition and recovery of constituents in the solid phase, as determined using two-step treatment with sulfuric acid, Py-GC/MS, and solid-state NMR, (iii) pseudo-lignin formation, (iv) furan aldehydes in condensates from the gas phase, (v) enzymatic digestibility of pretreated solids, (vi) enzyme inhibition by pretreatment liquids, and (vii) fermentability of pretreatment liquids using Saccharomyces cerevisiae yeast. Glucose and xylose were the predominant sugars in pretreatment liquids from SA-HTP and A-HTP, respectively. For A-HTP, the enzymatic digestibility of the pretreated solids was proportional to the SF, while for SA-HTP no clear trend was observed. The best enzymatic digestibility (above 80%) was achieved for A-HTP performed at SF 4.8. The highest total yields of glucose and xylose, the predominant sugars, were achieved for A-HTP at SF 3.8 and temperatures of 190 °C and 205 °C. The fermentability of the pretreatment liquids by Saccharomyces cerevisiae was lower for SA-HTP than for A-HTP. The investigation suggests that hydrothermal pretreatment of sugarcane bagasse can be performed with good results without addition of sulfuric acid, but that the conditions must be just harsh enough to almost quantitatively solubilize the hemicelluloses.
Rezzoug Sid-ahmed - One of the best experts on this subject based on the ideXlab platform.
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Combined steam-explosion toward vacuum and dilute-acid spraying of wheat straw. Impact of Severity Factor on enzymatic hydrolysis
Renewable Energy, 2015Co-Authors: Maache-rezzoug Zoulikha, Maugard Thierry, Zhao Jean-michel Qiuyu, Armelle Nouviaire, Rezzoug Sid-ahmedAbstract:This study deals with the development of an eco-friendly hydrothermal pretreatment of wheat straw. This pretreatment involves moderate temperatures without generation of liquid fractions allowing to reduce the energy input consumption and the environmental impact and enhance the enzymatic hydrolysis. For this purpose, the synergistic effect of impregnation of wheat straw by dilute sulfuric acid and DIC (in french: Detente instantannee Controlee) pretreatment on enzymatic hydrolysis has been investigated. DIC process involves subjecting the lignocellulosic biomass to saturated steam pressure (0.3–0.7 MPa), followed by a sudden decompression toward vacuum (5 kPa). The optimization of processing conditions was carried out using a full-Factorial design, in respect to processing temperature (133–165 °C), residence time (5–40 min) and sulfuric acid concentration (0.70–2.20%). These processing conditions were converted into a single combined Severity Factor (CS), relating pH, temperature and residence time of pretreatment, ranged from −2.22 to 1.25. The efficiency of proposed pretreatment was measured through the enzymatic digestibility of lignocellulose and the responses parameters of experimental design were the monomeric glucose and xylose. The most influential Factor on biomass bioconversion was sulfuric acid concentration followed by temperature and processing time. The optimum values were 2.2%, 165 °C and 40 min, for acid concentration, temperature and residence time, respectively. Strong correlations were observed between the enzymatic hydrolysis and conditions of pretreatment through the analysis of CS. The intense conditions have contributed to disrupt the biomass structure make it less dense leading to a higher specific surface area (ABET). Thus, increasing in accessibility of cellulose to enzymes has improved the rate and yields of bioconversion.
Pau Loke Show - One of the best experts on this subject based on the ideXlab platform.
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Torrefaction performance prediction approached by torrefaction Severity Factor
Fuel, 2019Co-Authors: Wei Hsin Chen, Ching Lin Cheng, Pau Loke ShowAbstract:Abstract Torrefaction is a crucial biomass upgrading technology to produce biochar for fuel, soil amendment, and bio-absorbent. A number of indicators such as weight loss (WL), torrefaction Severity index (TSI), and Severity Factor (SF) have been conducted to describe the torrefaction degree. However, operating conditions such as torrefaction temperature and duration are not considered in weight loss and torrefaction Severity index, while biomass nature is not taken into account in the Severity Factor. To overcome these drawbacks, an indicator termed torrefaction Severity Factor (TSF) is proposed by introducing a time exponent in the Severity Factor. Four different biomass materials of Chinese medicine residue, Arthrospira platensis residue, C. sp. JSC4, and spent coffee grounds are examined. After the optimization of the time exponent, TSF can accurately correlate weight loss and thereby torrefaction Severity, and improve the prediction up to 13% when compared to Severity Factor. In addition, the results suggest that TSF is able to appropriately predict the enhancement Factor of HHV and energy yield where the coefficient of determination (R2) is beyond 0.83. Overall, TSF has successfully combined the operating conditions (temperature and duration) and biomass species, can be utilized for predicting torrefaction performance. This gives a simple and fast way for torrefaction operation and reactor design, thereby achieving time-saving and efficient predictions.