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Naseem Ahmed - One of the best experts on this subject based on the ideXlab platform.

  • study on effects of temperature moisture and ph in Degradation and Degradation Kinetics of aldrin endosulfan lindane pesticides during full scale continuous rotary drum composting
    Chemosphere, 2014
    Co-Authors: A A Kazmi, Naseem Ahmed
    Abstract:

    Abstract Study focused on effects of temperature, moisture and pH on Degradation and Degradation Kinetics of aldrin, endosulfan (α), endosulfan (β) and lindane during vegetable waste composting using full-scale continuous rotary drum composter (FSCRDC). Extraction, concentration and quantification of pesticides were made from waste material at different stages by ultra-sonification, silica gel column and GC–MS analysis. Removal efficiency of aldrin, endosulfan α, endosulfan β and lindane was found 85.67%, 84.95%, 83.20% and 81.36% respectively due to optimum temperature, moisture, pH and enhanced microbial activity. Maximum temperature in inlet zone was found 60–65 °C which is most suitable for complex microbial population. After feeding and turning in inlet zone, temperature reduced to 38 °C from 60 to 65 °C and regained it within 7–8 h, and pH reduced to 5.3 ± 0.2 from 7.5 ± 0.3 in 4 h and regained it in 10 h. Heterotrophic bacteria Bacillus sp., Pseudomonas sp. and Lactobacillus sp. also decreased from 4.4 × 10 3 to 7.80 × 10 2  CFU g −1 in 2 h due to gradual variation in temperature and pH. No significant temperature change was found in middle and outlet zones during feeding and turning. Degradation of pesticides was observed as first order Kinetics and half-life of aldrin, endosulfan α, endosulfan β and lindane was reduced to 25.54, 18.43, 18.43 and 27.43 d from 1095, 60, 270 and 160 d respectively. Thus, the observations in contrast of removal and Degradation Kinetics of organochlorine pesticides residues in vegetable waste though full-scale rotary drum composting proved it the best suited technique.

  • study on effects of temperature moisture and ph in Degradation and Degradation Kinetics of aldrin endosulfan lindane pesticides during full scale continuous rotary drum composting
    Chemosphere, 2014
    Co-Authors: A A Kazmi, Naseem Ahmed
    Abstract:

    Abstract Study focused on effects of temperature, moisture and pH on Degradation and Degradation Kinetics of aldrin, endosulfan (α), endosulfan (β) and lindane during vegetable waste composting using full-scale continuous rotary drum composter (FSCRDC). Extraction, concentration and quantification of pesticides were made from waste material at different stages by ultra-sonification, silica gel column and GC–MS analysis. Removal efficiency of aldrin, endosulfan α, endosulfan β and lindane was found 85.67%, 84.95%, 83.20% and 81.36% respectively due to optimum temperature, moisture, pH and enhanced microbial activity. Maximum temperature in inlet zone was found 60–65 °C which is most suitable for complex microbial population. After feeding and turning in inlet zone, temperature reduced to 38 °C from 60 to 65 °C and regained it within 7–8 h, and pH reduced to 5.3 ± 0.2 from 7.5 ± 0.3 in 4 h and regained it in 10 h. Heterotrophic bacteria Bacillus sp., Pseudomonas sp. and Lactobacillus sp. also decreased from 4.4 × 10 3 to 7.80 × 10 2  CFU g −1 in 2 h due to gradual variation in temperature and pH. No significant temperature change was found in middle and outlet zones during feeding and turning. Degradation of pesticides was observed as first order Kinetics and half-life of aldrin, endosulfan α, endosulfan β and lindane was reduced to 25.54, 18.43, 18.43 and 27.43 d from 1095, 60, 270 and 160 d respectively. Thus, the observations in contrast of removal and Degradation Kinetics of organochlorine pesticides residues in vegetable waste though full-scale rotary drum composting proved it the best suited technique.

Matthias Peuster - One of the best experts on this subject based on the ideXlab platform.

  • Biocompatibility of fluoride-coated magnesium-calcium alloys with optimized Degradation Kinetics in a subcutaneous mouse model.
    Journal of biomedical materials research. Part A, 2012
    Co-Authors: Andreas Drynda, Juliane Seibt, Thomas Hassel, Friedrich-wilhelm Bach, Matthias Peuster
    Abstract:

    The principle of bioDegradation has been considered for many years in the development of cardiovascular stents, especially for patients with congenital heart defects. A variety of materials have been examined with regard to their suitability for cardiovascular devices. Iron- and magnesium-based stents were investigated intensively during the last years. It has been shown, that iron, or iron based alloys have slow Degradation Kinetics whereas magnesium-based systems exhibit rapid Degradation rates. Recently we have developed fluoride coated binary magnesium-calcium alloys with reduced Degradation Kinetics. These alloys exhibit good biocompatibility and no major adverse effects toward smooth muscle and endothelial cells in in vitro experiments. In this study, these alloys were investigated in a subcutaneous mouse model. Fluoride coated (fc) magnesium, as well as MgCa0.4%, MgCa0.6%, MgCa0.8%, MgCa1.0%, and a commercially available WE43 alloy were implanted in form of (fc) cylindrical plates into the subcutaneous tissue of NMRI mice. After a 3 and 6 months follow-up, the (fc) alloy plates were examined by histomorphometric techniques to assess their Degradation rate in vivo. Our data indicate that all (fc) alloys showed a significant corrosion. For both time points the (fc) MgCa alloys showed a higher corrosion rate in comparison to the (fc) WE43 reference alloy. Significant adverse effects were not observed. Fluoride coating of magnesium-based alloys can be a suitable way to reduce Degradation rates. However, the (fc) MgCa alloys did not exhibit decreased Degradation Kinetics in comparison to the (fc) WE43 alloy in a subcutaneous mouse model.

  • development and biocompatibility of a novel corrodible fluoride coated magnesium calcium alloy with improved Degradation Kinetics and adequate mechanical properties for cardiovascular applications
    Journal of Biomedical Materials Research Part A, 2009
    Co-Authors: Andreas Drynda, Thomas Hassel, Friedrich-wilhelm Bach, Rene Hoehn, Angela Perz, Matthias Peuster
    Abstract:

    Recently, corrodible magnesium-based alloys have been introduced for use as cardiovascular stents and orthopedic implants. However, rapid corrosion rates have raised questions about their biocompatibility. Therefore, we developed a binary fluoride-coated magnesium-calcium alloy with improved Degradation Kinetics. Biocompatibility of the alloys was evaluated with metabolic assays (colorimetric WST-1 test). Furthermore, five different probes of magnesium-calcium alloys (MgCa 0.4, 0.6, 0.8, 1.2, and 2.0 wt %) were cocultivated with human smooth muscle cells and endothelial cells. To investigate the decomposition Kinetics in a physiological environment the alloys were used untreated and fluoride coated (MgF2). Mg and Ca decreased the metabolic activity in vascular cells dose-dependently, with cytotoxic effects only at unphysiological concentrations. Uncoated magnesium alloys showed signs of decomposition after a short incubation time of 24 h in contrast to MgF2 coated alloys. After 10 days smooth muscle and endothelial cells around the alloys were still alive, whereas colonization of the surfaces was only observed for smooth muscle cells. The fluoride-coated MgCa alloys exhibited good results concerning mechanical properties, Degradation Kinetics, and biocompatibility in vitro. We conclude that a binary fluoride magnesium-calcium alloy is a promising candidate for the production of cardiovascular stents. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

A A Kazmi - One of the best experts on this subject based on the ideXlab platform.

  • study on effects of temperature moisture and ph in Degradation and Degradation Kinetics of aldrin endosulfan lindane pesticides during full scale continuous rotary drum composting
    Chemosphere, 2014
    Co-Authors: A A Kazmi, Naseem Ahmed
    Abstract:

    Abstract Study focused on effects of temperature, moisture and pH on Degradation and Degradation Kinetics of aldrin, endosulfan (α), endosulfan (β) and lindane during vegetable waste composting using full-scale continuous rotary drum composter (FSCRDC). Extraction, concentration and quantification of pesticides were made from waste material at different stages by ultra-sonification, silica gel column and GC–MS analysis. Removal efficiency of aldrin, endosulfan α, endosulfan β and lindane was found 85.67%, 84.95%, 83.20% and 81.36% respectively due to optimum temperature, moisture, pH and enhanced microbial activity. Maximum temperature in inlet zone was found 60–65 °C which is most suitable for complex microbial population. After feeding and turning in inlet zone, temperature reduced to 38 °C from 60 to 65 °C and regained it within 7–8 h, and pH reduced to 5.3 ± 0.2 from 7.5 ± 0.3 in 4 h and regained it in 10 h. Heterotrophic bacteria Bacillus sp., Pseudomonas sp. and Lactobacillus sp. also decreased from 4.4 × 10 3 to 7.80 × 10 2  CFU g −1 in 2 h due to gradual variation in temperature and pH. No significant temperature change was found in middle and outlet zones during feeding and turning. Degradation of pesticides was observed as first order Kinetics and half-life of aldrin, endosulfan α, endosulfan β and lindane was reduced to 25.54, 18.43, 18.43 and 27.43 d from 1095, 60, 270 and 160 d respectively. Thus, the observations in contrast of removal and Degradation Kinetics of organochlorine pesticides residues in vegetable waste though full-scale rotary drum composting proved it the best suited technique.

  • study on effects of temperature moisture and ph in Degradation and Degradation Kinetics of aldrin endosulfan lindane pesticides during full scale continuous rotary drum composting
    Chemosphere, 2014
    Co-Authors: A A Kazmi, Naseem Ahmed
    Abstract:

    Abstract Study focused on effects of temperature, moisture and pH on Degradation and Degradation Kinetics of aldrin, endosulfan (α), endosulfan (β) and lindane during vegetable waste composting using full-scale continuous rotary drum composter (FSCRDC). Extraction, concentration and quantification of pesticides were made from waste material at different stages by ultra-sonification, silica gel column and GC–MS analysis. Removal efficiency of aldrin, endosulfan α, endosulfan β and lindane was found 85.67%, 84.95%, 83.20% and 81.36% respectively due to optimum temperature, moisture, pH and enhanced microbial activity. Maximum temperature in inlet zone was found 60–65 °C which is most suitable for complex microbial population. After feeding and turning in inlet zone, temperature reduced to 38 °C from 60 to 65 °C and regained it within 7–8 h, and pH reduced to 5.3 ± 0.2 from 7.5 ± 0.3 in 4 h and regained it in 10 h. Heterotrophic bacteria Bacillus sp., Pseudomonas sp. and Lactobacillus sp. also decreased from 4.4 × 10 3 to 7.80 × 10 2  CFU g −1 in 2 h due to gradual variation in temperature and pH. No significant temperature change was found in middle and outlet zones during feeding and turning. Degradation of pesticides was observed as first order Kinetics and half-life of aldrin, endosulfan α, endosulfan β and lindane was reduced to 25.54, 18.43, 18.43 and 27.43 d from 1095, 60, 270 and 160 d respectively. Thus, the observations in contrast of removal and Degradation Kinetics of organochlorine pesticides residues in vegetable waste though full-scale rotary drum composting proved it the best suited technique.

Deyi Wang - One of the best experts on this subject based on the ideXlab platform.

  • thermal oxidative Degradation Kinetics of novel intumescent flame retardant polypropylene composites
    Journal of Thermal Analysis and Calorimetry, 2015
    Co-Authors: Shibin Nie, Can Zhou, Chao Peng, Lei Liu, Chi Zhang, Xiang Dong, Deyi Wang
    Abstract:

    Novel intumescent flame-retardant polypropylene (PP) composites were prepared based on a char-forming agent (CFA) and silica-gel microencapsulated APP (Si-MCAPP). The thermal oxidative Degradation Kinetics of pure PP and the flame-retardant PP composites were investigated using Kissinger method, Flynn–Wall–Ozawa method and Coats–Redfern method. The results show that the value of the activation energy of the samples has the same sequence that obtained by three methods. The sample with CFA/Si-MCAPP = 1:3 has highest activation energy, and pure PP has the lowest activation energy. The reaction orders of pure PP and flame-retardant PP composites are also calculated by Coats–Redfern method. The results of thermal oxidative Degradation Kinetics of flame-retardant PP composites provide useful date for understanding the flame-retardant behaviours of novel intumescent flame-retardant PP composites with different intumescent flame-retardant system.

Andreas Drynda - One of the best experts on this subject based on the ideXlab platform.

  • Biocompatibility of fluoride-coated magnesium-calcium alloys with optimized Degradation Kinetics in a subcutaneous mouse model.
    Journal of biomedical materials research. Part A, 2012
    Co-Authors: Andreas Drynda, Juliane Seibt, Thomas Hassel, Friedrich-wilhelm Bach, Matthias Peuster
    Abstract:

    The principle of bioDegradation has been considered for many years in the development of cardiovascular stents, especially for patients with congenital heart defects. A variety of materials have been examined with regard to their suitability for cardiovascular devices. Iron- and magnesium-based stents were investigated intensively during the last years. It has been shown, that iron, or iron based alloys have slow Degradation Kinetics whereas magnesium-based systems exhibit rapid Degradation rates. Recently we have developed fluoride coated binary magnesium-calcium alloys with reduced Degradation Kinetics. These alloys exhibit good biocompatibility and no major adverse effects toward smooth muscle and endothelial cells in in vitro experiments. In this study, these alloys were investigated in a subcutaneous mouse model. Fluoride coated (fc) magnesium, as well as MgCa0.4%, MgCa0.6%, MgCa0.8%, MgCa1.0%, and a commercially available WE43 alloy were implanted in form of (fc) cylindrical plates into the subcutaneous tissue of NMRI mice. After a 3 and 6 months follow-up, the (fc) alloy plates were examined by histomorphometric techniques to assess their Degradation rate in vivo. Our data indicate that all (fc) alloys showed a significant corrosion. For both time points the (fc) MgCa alloys showed a higher corrosion rate in comparison to the (fc) WE43 reference alloy. Significant adverse effects were not observed. Fluoride coating of magnesium-based alloys can be a suitable way to reduce Degradation rates. However, the (fc) MgCa alloys did not exhibit decreased Degradation Kinetics in comparison to the (fc) WE43 alloy in a subcutaneous mouse model.

  • development and biocompatibility of a novel corrodible fluoride coated magnesium calcium alloy with improved Degradation Kinetics and adequate mechanical properties for cardiovascular applications
    Journal of Biomedical Materials Research Part A, 2009
    Co-Authors: Andreas Drynda, Thomas Hassel, Friedrich-wilhelm Bach, Rene Hoehn, Angela Perz, Matthias Peuster
    Abstract:

    Recently, corrodible magnesium-based alloys have been introduced for use as cardiovascular stents and orthopedic implants. However, rapid corrosion rates have raised questions about their biocompatibility. Therefore, we developed a binary fluoride-coated magnesium-calcium alloy with improved Degradation Kinetics. Biocompatibility of the alloys was evaluated with metabolic assays (colorimetric WST-1 test). Furthermore, five different probes of magnesium-calcium alloys (MgCa 0.4, 0.6, 0.8, 1.2, and 2.0 wt %) were cocultivated with human smooth muscle cells and endothelial cells. To investigate the decomposition Kinetics in a physiological environment the alloys were used untreated and fluoride coated (MgF2). Mg and Ca decreased the metabolic activity in vascular cells dose-dependently, with cytotoxic effects only at unphysiological concentrations. Uncoated magnesium alloys showed signs of decomposition after a short incubation time of 24 h in contrast to MgF2 coated alloys. After 10 days smooth muscle and endothelial cells around the alloys were still alive, whereas colonization of the surfaces was only observed for smooth muscle cells. The fluoride-coated MgCa alloys exhibited good results concerning mechanical properties, Degradation Kinetics, and biocompatibility in vitro. We conclude that a binary fluoride magnesium-calcium alloy is a promising candidate for the production of cardiovascular stents. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010