Measurement Uncertainty of Chromogenic LAL Assays: Reaction Time and Proportion of Endotoxin and LAL Reagent Affect Release of p-Nitroaniline

2015 ◽  
Vol 98 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Celina Silva Ostronoff ◽  
Felipe Rebello Lourenço
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Measurement Uncertainty ◽  
Medical Devices ◽  
Bacterial Endotoxin ◽  
Limulus Amebocyte Lysate ◽  
End Point ◽  
Bacterial Endotoxins ◽  
Endotoxin Content ◽  
Detection And Quantification

Abstract Limulus Amebocyte Lysate (LAL) assays are widely used for detection and quantification of bacterial endotoxins in pharmaceuticals and medical devices. However, there are only a few studies on the measurement uncertainty of LAL assays. The aim of this work was to identify and quantify the main sources of measurement uncertainty for end point and kinetic-chromogenic LAL assays. Response surface methodology was used to study how the release of p-nitroaniline (pNA)is affected by reaction time and proportion of endotoxin and LAL reagent in end point and kinetic-chromogenic LAL assays, respectively. Increased release ofpNA was observed when reaction time was increased. In addition, if different volumes of sample (or endotoxin standard) and LAL reagent are used, the pNA release rate will be affected. These results may be dueto the increased interaction between the bacterial endotoxin and LAL-activated enzyme. Final measurementuncertainties (95% confidence interval) were 90–120% and 90–127% of bacterial endotoxin content for end point and kinetic-chromogenic assays, respectively. These values are reasonable for the scope of the method and allow the application of thesemeasurement uncertainties in routine analysis of pharmaceuticals and medical devices.

Optimization of Magnesium Separation and Extraction from Boron Slurry Using Response Surface Methodology

2011 ◽  
Vol 366 ◽  
pp. 366-369
Author(s):  
Feng Gao ◽  
Rong Fu ◽  
Ming Yang Qian ◽  
Zhu Min Wang ◽  
Xiang Zhang
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Factorial Design ◽  
Response Surface ◽  
Reaction Temperature ◽  
Fractional Factorial Design ◽  
Design Criterion ◽  
Fractional Factorial ◽  
Effective Factors

Response surface methodology was used to optimize the soaking Mg leaching ratio from the boron slurry screened by 25 fractional factorial design. Five effective factors such as H2SO4 concentrations, reaction time, reaction temperature and stir velocity were tested by using 25 fractional factorial design criterion and three effective factors H2SO4 concentrations, reaction time and reaction temperature showed significant effect(P2SO4 concentrations of 0.29mol/l, reaction time of 90 min and reaction temperature of 50°C. Three runs of additional confirmation experiments were conducted. The mixture magnesium leaching value was 58.20%.

scholarly journals Optimization of Synthesis of Seleno-Sargassum fusiforme(Harv.) Setch. Polysaccharide by Response Surface Methodology, Its Characterization, and Antioxidant Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Bin Ji ◽  
Fang Dong ◽  
Miao Yu ◽  
Long Qin ◽  
Dan Liu
Keyword(s):  
Antioxidant Activity ◽  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Reaction Temperature ◽  
Sargassum Fusiforme ◽  
Synthesis Conditions ◽  
Optimum Reaction ◽  
Series Of Experiments

The response surface methodology was employed to optimize the synthesis conditions of seleno-Sargassum fusiforme(Harv.) Setch. polysaccharide. Three independent variables (reaction time, reaction temperature, and ratio of Na2SeO3to SFPSI) were tested. Furthermore, the characterization and antioxidant activity of Se-SFPSIin vivowere investigated. The result showed that the actual experimental Se content of Se-SFPSI was 3.352 mg/g at the optimum reaction conditions of reaction time 8 h, reaction temperature 71°C, and ratio of Na2SeO3to SFPSIB 1.0 g/g. A series of experiments showed that the characterization of Se-SFPSIB was significantly different from that of SFPSIB. Additionally, antioxidant activity assay indicated that the Se-SFPSIB could increase catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity of mice bearing tumor S180in blood, heart, and liver while decreasing malondialdehyde (MDA) levels. It can be concluded that selenylation is a feasible approach to obtain seleno-polysaccharide which was utilized as highly biological medicine or functional food.

scholarly journals Optimized Degradation of Eosin Dye Through UV-ZnO NPs Catalyzed Reaction

2021 ◽  
Author(s):  
Rania Farouq ◽  
Ehsan Kh. Ismaeel ◽  
Aliaa M. Monazie
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Flow Rate ◽  
Zno Nanoparticles ◽  
Effective Parameters ◽  
Zno Nps ◽  
Statistical Tool ◽  
Box Behnken Design ◽  
Influential Parameters ◽  
Dye Solutions

Abstract The present study is set out to determine the photocatalytic degradation potential of ZnO nanoparticles for effective degradation of Eosin dye. The heterogeneous photocatalytic experiments were carried out by irradiating aqueous dye solutions with ultraviolet light. The influence of effective parameters like flow rate, pH, catalyst dose, and dye concentration was examined. The best degradation efficiency (66.82%) of ZnO Nanoparticles against Eosin dye was achieved within 90 min of reaction time. The Box–Behnken design under the Response Surface Methodology (RSM) was chosen as a statistical tool to obtain the correlation of influential parameters. The optimum values were recorded as follows: 0.59 g, 15.75 ppm and 136.12 ml/min for amount of catalyst, dye concentration and flow rate, respectively. The maximum percent degradation achieved at these conditions was 71.44%.

scholarly journals Optimization of Enzymatic Synthesis of Betulinic Acid Amide in Organic Solvent by Response Surface Methodology (RSM)

2019 ◽  
Vol 19 (4) ◽  
pp. 849
Author(s):  
Nurul Atikah Amin Yusof ◽  
Nursyamsyila Mat Hadzir ◽  
Siti Efliza Ashari ◽  
Nor Suhaila Mohamad Hanapi ◽  
Rossuriati Dol Hamid
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Reaction Temperature ◽  
Betulinic Acid ◽  
Enzymatic Synthesis ◽  
Acid Amide ◽  
Molar Ratio ◽  
Percentage Yield ◽  
Substrate Molar Ratio

Optimization of the lipase catalyzed enzymatic synthesis of betulinic acid amide in the presence of immobilized lipase, Novozym 435 from Candida antartica as a biocatalyst was studied. Response surface methodology (RSM) and 5-level-4-factor central-composite rotatable design (CCRD) were employed to evaluate the effects of the synthesis parameters, such as reaction time (20–36 h), reaction temperature (37–45 °C), substrate molar ratio of betulinic acid to butylamine (1:1–1:3), and enzyme amounts (80–120 mg) on the percentage yield of betulinic acid amide by direct amidation reaction. The optimum conditions for synthesis were: reaction time of 28 h 33 min, reaction temperature of 42.92 °C, substrate molar ratio of 1:2.21, and enzyme amount of 97.77 mg. The percentage yield of actual experimental values obtained 65.09% which compared well with the maximum predicted value of 67.23%. The obtained amide was characterized by GC, GCMS and 13C NMR. Betulinic acid amide (BAA) showed a better cytotoxicity compared to betulinic acid as the concentration inhibited 50% of the cell growth (IC50) against MDA-MB-231 cell line (IC50 < 30 µg/mL).

scholarly journals Two-Step Production of Neofructo-Oligosaccharides Using Immobilized Heterologous Aspergillus terreus 1F-Fructosyltransferase Expressed in Kluyveromyces lactis and Native Xanthophyllomyces dendrorhous G6-Fructosyltransferase

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 673 ◽  
Author(s):  
Burghardt ◽  
Baas ◽  
Gerlach ◽  
Czermak
Keyword(s):  
Response Surface Methodology ◽  
Enzyme Activity ◽  
Reaction Time ◽  
Aspergillus Terreus ◽  
Kluyveromyces Lactis ◽  
Xanthophyllomyces Dendrorhous ◽  
Initial Concentration ◽  
Total Enzyme Activity ◽  
Glycosidic Bonds ◽  
Total Enzyme

Fructo-oligosaccharides (FOS) are prebiotic low-calorie sweeteners that are synthesized by the transfer of fructose units from sucrose by enzymes known as fructosyltransferases. If these enzymes generate β-(2,6) glycosidic bonds, the resulting oligosaccharides belong to the neoseries (neoFOS). Here, we characterized the properties of three different fructosyltransferases using a design of experiments approach based on response surface methodology with a D-optimal design. The reaction time, pH, temperature, and substrate concentration were used as parameters to predict three responses: The total enzyme activity, the concentration of neoFOS and the neoFOS yield relative to the initial concentration of sucrose. We also conducted immobilization studies to establish a cascade reaction for neoFOS production with two different fructosyltransferases, achieving a total FOS yield of 47.02 ± 3.02%. The resulting FOS mixture included 53.07 ± 1.66 mM neonystose (neo-GF3) and 20.8 ± 1.91 mM neo-GF4.

The Limulus Amoebocyte Lysate Assay for Bacterial Endotoxins

1985 ◽  
Vol 13 (3) ◽  
pp. 180-192
Author(s):  
A. Christine McCartney
Keyword(s):  
Medical Devices ◽  
Limulus Amoebocyte Lysate ◽  
Bacterial Endotoxins

The Limulus amoeboecyte lysate (LAL) test not only provides a means for the detection and quantitation of endotoxin in parenteral preparations and medical devices to be used for the benefit of man without recourse to the use of animals, but also provides a more precise assay than the traditional rabbit test.

Optimization of Synthesis Technology of Acetylferrocene by Response Surface Methodology

2012 ◽  
Vol 622-623 ◽  
pp. 162-165
Author(s):  
Da Wei Yin ◽  
Gang Tao Liang ◽  
Xiao Ming Sun ◽  
Yu Ting Liu
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Acetyl Chloride ◽  
Raw Materials ◽  
Raw Material ◽  
Interactive Effects ◽  
Percentage Yield ◽  
Experimental Yield ◽  
Central Composite

Acetylferrocene was synthesized by acetyl chloride and ferrocene as raw materials, dichloromethane as the solvent, and ZnO as catalyst. Response surface methodology based on three-level, three-variable central composite rotable design was used to evaluate the interactive effects of the ratio of acetyl chloride and ferrocene(2-4), the amount of ZnO(1.0-1.3mol), reaction time(30-60 min)on the percentage yield of acylferrocene. The optimal raw material ratio, amount catalyst, and reaction time was 3:1, 1.19mol, 40min. Under the optimum conditions, the actual experimental yield can reach 86.72%.

scholarly journals ALTERATIONS IN THE BLOOD COAGULATION SYSTEM INDUCED BY BACTERIAL ENDOTOXIN

1958 ◽  
Vol 107 (3) ◽  
pp. 353-367 ◽  
Author(s):  
Donald G. McKay ◽  
Sandor S. Shapiro
Keyword(s):  
Blood Coagulation ◽  
Marked Decrease ◽  
Fibrinogen Level ◽  
Normal Values ◽  
Bacterial Endotoxin ◽  
Coagulation System ◽  
Bacterial Endotoxins ◽  
Shwartzman Reaction ◽  
The One

The intravenous injection of bacterial endotoxins alter the coagulation system of rabbits' blood in vivo. Twenty-four hours after the first injection the fibrinogen level rises to twice normal values. The second injection at this time causes a 30 to 40 per cent decrease in fibrinogen content in 4 hours. Twenty hours later it again rises to twice normal values. A marked decrease in whole blood coagulation times in silicone occurs 4 hours after both injections but rises to normal values 24 hours following each injection. The circulating platelets drop from average levels of 300,000/c.mm. to 150,000/c.mm. after the first injection. The platelets remain at this low level and decrease to less than 100,000 after the second injection. During this time no fibrinolytic or fibrinogenolytic activity can be detected. Also, there is no significant change in the one stage prothrombin times or antithrombin titres. The marked decrease in circulating fibrinogen at the time when intracapillary thrombi are formed suggests that the "hyaline" thrombi of the generalized Shwartzman reaction are composed, in part, of fibrin. There appears to be a relationship between the level of circulating fibrinogen at the time of injection of bacterial endotoxin and the extent of the thrombosis. The higher the preinjection fibrinogen level, the more extensive is the thrombosis. There is also a relationship between the amount of fibrinogen loss and the extent of thrombosis after the injection. The more extensive the thrombosis the greater is the postinjection decrease in circulating fibrinogen. A comparison between the response of the hemostatic mechanism to tissue thromboplastin and bacterial endotoxin indicates that the latter acts in a unique manner and not by way of a simple "thromboplastic" activity. From the hematological standpoint, "preparation" for the generalized Shwartzman reaction is accompanied by an increased circulating fibrinogen, leukocytosis, and thrombocytopenia.

Response Surface Methodology Optimization and Kinetic Study of Ultrafiltration-Enhanced, SCER-catalyzed Hydrolysis of Lard

2019 ◽  
Vol 17 (8) ◽  
Author(s):  
Enmin Lv ◽  
Shaoxuan Ding ◽  
Jie Lu ◽  
Zhuang Li ◽  
Lixiong Du ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Membrane Separation ◽  
Molar Ratio ◽  
Transmembrane Pressure ◽  
Cleaning Efficiency ◽  
Membrane Cleaning ◽  
Exponential Factor ◽  
Hydrolysis Of

Abstract The integration process of polyethersulphone (PES) ultrafiltration with catalytic hydrolysis of lard was optimized by response surface methodology (RSM). The influences of molar ratio of water to lard, reaction time and transmembrane pressure on the fatty acids (FAs) yield were investigated. Results showed that the maximum FAs yield of 99.52 % was obtained under the optimized conditions of molar ratio of water to lard of 6.0:1.0, reaction time of 10.0 h and transmembrane pressure of 100.0 kPa. Moreover, the membrane cleaning efficiency was studied after four cleanings. Furthermore, the kinetic model of membrane separation process was investigated and the activation energy and pre-exponential factor were determined.

Optimization of melon oil methyl ester production using response surface methodology

2017 ◽  
Vol 2 (1) ◽  
pp. 1-10 ◽  
Author(s):  
O. S. Aliozo ◽  
L. N. Emembolu ◽  
O. D. Onukwuli
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Methyl Ester ◽  
Response Surface ◽  
Research Work ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Central Composite Designs ◽  
American Society

Abstract In this research work, melon oil was used as feedstock for methyl ester production. The research was aimed at optimizing the reaction conditions for methyl ester yield from the oil. Response surface methodology (RSM), based on a five level, four variable central composite designs (CCD)was used to optimize and statistically analyze the interaction effect of the process parameter during the biodiesel production processes. A total of 30 experiments were conducted to study the effect of methanol to oil molar ratio, catalyst weight, temperature and reaction time. The optimal yield of biodiesel from melon oil was found to be 94.9% under the following reaction conditions: catalyst weight - 0.8%, methanol to oil molar ratio - 6:1, temperature - 55°C and reaction time of 60mins. The quality of methyl ester produced at these conditions was within the American Society for Testing and Materials (ASTM D6751) specification.

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