scholarly journals Effect of Drying Processes on Stability of Anthocyanin Extracts from Saffron Petal

2014 ◽  
Vol 2 ◽  
pp. 13-18 ◽  
Author(s):  
Somayeh Heydari ◽  
Roya Rezaei ◽  
Gholam Hossein Haghayegh
Keyword(s):  
Room Temperature ◽  
Heating Temperature ◽  
Heating Time ◽  
Crocus Sativus ◽  
The Sun ◽  
Processing Treatment ◽  
Different Temperatures ◽  
The Stability ◽  
Synthetic Pigments ◽  
Good Substitute

Saffron (Crocus sativus) has cyanic color flowers with major colorant of anthocyanin. Attractive color and functional properties of anthocyanins make them a good substitute for synthetic pigments in the food industry. These natural soluble water colorants are rather unstable and influenced by final processing treatment. The drying process is critical to the stability of saffron petals anthocyanins. Four different dehydration methods were evaluated: traditional method (at room temperature and under the sun); dehydration with electrical oven at different temperatures; and dehydration with microwave at different powers. The results showed that the highest amount of anthocyanin was obtained when saffron petals treated by traditional methods (at room temperature and under the sun). According to the results, the stability of saffron petals anthocyanins gradually accessed with increase of the heating temperature and decrement of heating time until 100 °C. However, heated at 120 and 140 °C, the anthocyanins could break down, and their residual amounts declined within 20 min and 10 min, respectively. The results suggested that saffron petals anthocyanins tended to degrade at high temperatures (>100 °C). Between these methods, drying at room temperature and drying with microwave at 900 W obtained the highest and the lowest results respectively.

scholarly journals Effects of Temperature on Bending Properties of Three-Dimensional and Five-Directional Braided Composite

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3977
Author(s):  
Li ◽  
Jia ◽  
Pei ◽  
Wan ◽  
Li ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Room Temperature ◽  
Bending Strength ◽  
Heating Temperature ◽  
Three Dimensional ◽  
Heating Time ◽  
Resin Composites ◽  
Bending Properties ◽  
Different Temperatures ◽  
Epoxy Resin Composites

The bending properties of three-dimensional (3Dim) and five-directional (5Dir) braided/epoxy resin composites at room temperature, 90 °C, 110 °C, and 150 °C and heating for 0.25 h, 10 h, and 30 h, respectively, were studied. The effect of different temperatures and heating times on the bending property of these composites was discussed. The results showed that the bending strength of these composites at 90 °C, 110 °C, and 150 °C and heating time of 0.25 h is 33.86%, 46.27%, and 83.94% lower, respectively, than that at room temperature. In addition, 3Dim–5Dir braided composites exhibit different damage modes at different temperatures, revealing different failure mechanisms. Heating temperature has greater influence on the bending properties of these composites than heating time. The results provided a basis for the application of resin-based 3Dim–5Dir braided/epoxy resin composites at different temperatures.

Conductivities of Room Temperature Molten Salts Containing ZnCl2, Measured by a Computerized Direct Current Method

2002 ◽  
Vol 57 (3-4) ◽  
pp. 129-135
Author(s):  
Hsin-Yi Hsu ◽  
Chao-Chen Yang
Keyword(s):  
Activation Energy ◽  
Direct Current ◽  
Molten Salts ◽  
Room Temperature ◽  
Current Method ◽  
Cross Linking ◽  
Infra Red ◽  
Different Temperatures ◽  
The Stability ◽  
Benzyltriethylammonium Chloride

The conductivities of the binary room-temperature molten salt (RTMS) systems ZnCl2-N-nbutylpyridinium chloride (BPC), ZnCl2 -1-ethyl-3-methylimidazolium chloride (EMIC) and ZnCl2 - benzyltriethylammonium chloride (BTEAC) have been measured at different temperatures and compositions by a d.c. four-probes method. The conductivities of the three RTMS are in the order ZnCl2-EMIC > ZnCl2-BPC > ZnCl2-BTEAC. In ZnCl2-BPC the conductivity at 70 to 150 °C, is maximal for 40 mol% ZnCl2. In ZnCl2 - EMIC, the conductivity below 130 °C is almost constant for 30 to 50 mol% ZnCl2 and has the lowest activation energy 25.21 kJ/mol. For these two systems, the conductivities decrease rapidly beyond 50 mol% ZnCl2 owing to the rapid increase in cross-linking and resultant tightening of the polyelectrolyte structure. As to the ZnCl2-BTEAC system, the conductivities at 110 - 150 °C decrease slowly for 30 - 60 mol% ZnCl2. The conductivities of the ZnCl2-EMICmelt are compared with those of the AlCl3-EMIC melt previously studied. The stability of the ZnCl2-EMIC melt system is explored by the effect of the environment on the conductivity and the Far Transmission Infra Red (FTIR) spectrum. It reveals that the effect is slight, and that the ZnCl2-EMIC melt may be classified as stable.

scholarly journals Stability of the Combination of Ceftazidime and Cephazolin in Icodextrin or PH Neutral Peritoneal Dialysis Solution

2014 ◽  
Vol 34 (2) ◽  
pp. 212-218 ◽  
Author(s):  
Rahul P. Patel ◽  
Madhur D. Shastri ◽  
Mohammad Bakkari ◽  
Troy Wanandy ◽  
Matthew D. Jose
Keyword(s):  
Peritoneal Dialysis ◽  
Body Temperature ◽  
High Performance ◽  
Room Temperature ◽  
Storage Conditions ◽  
Initial Concentration ◽  
Dialysis Solution ◽  
Different Temperatures ◽  
Colour Changes ◽  
The Stability

IntroductionThe objective of this study was to investigate the stability of ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral peritoneal dialysis (PD) solution.MethodsCeftazidime and cephazolin were injected into either a 7.5% icodextrin or pH neutral PD bag to obtain the concentration of 125 mg/L of each antibiotic. A total of nine 7.5% icodextrin or pH neutral PD bags containing ceftazidime and cephazolin were prepared and stored at 1 of 3 different temperatures: 4°C in a domestic refrigerator; 25°C at room temperature; or 37°C (body temperature) in an incubator. An aliquot was withdrawn immediately before (0 hour) or after 12, 24, 48, 96, 120, 144, 168 and 336 hours of storage. Each sample was analyzed in duplicate for the concentration of ceftazidime and cephazolin using a stability-indicating high-performance liquid chromatography technique. Ceftazidime and cephazolin were considered stable if they retained more than 90% of their initial concentration. Samples were also assessed for pH, colour changes and evidence of precipitation immediately after preparation and on each day of analysis.ResultsCeftazidime and cephazolin in both types of PD solution retained more than 90% of their initial concentration for 168 and 336 hours respectively when stored at 4°C. Both of the antibiotics lost more than 10% of the initial concentration after 24 hours of storage at 25 or 37°C. There was no evidence of precipitation at any time under the tested storage conditions. Change in the pH and color was observed at 25 and 37°C, but not at 4°C.ConclusionPremixed ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral PD solution is stable for at least 168 hours when refrigerated. This allows the preparation of PD bags in advance, avoiding the necessity for daily preparation. Both the antibiotics are stable for at least 24 hours at 25 and 37°C, permitting storage at room temperature and pre-warming of PD bags to body temperature prior to its administration.

scholarly journals The Effect of Heating on Surface Microhardness of Resin-based Materials for Direct Restoration

2018 ◽  
Vol 55 (4) ◽  
pp. 584-589
Author(s):  
Simona Stoleriu ◽  
Gianina Iovan ◽  
Irina Nica ◽  
Galina Pancu ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Vickers Microhardness ◽  
Composite Resin ◽  
Heating Temperature ◽  
Surface Hardness ◽  
Mean Value ◽  
Direct Restoration ◽  
Different Temperatures ◽  
Materials Used ◽  
Hardness Values

The aim of this study was to evaluate and to compare the surface hardness of three types of resin-based materials used for direct restoration after heating at different temperatures. A giomer (Beautifil II, Shofu Dental), a compomer (Dyract eXtra, Dentsply Sirona) and a hybrid composite resin (Gaenial Posterior, GC Corporation) were selected for this study. Twenty disk-shaped specimens of each material were heated at room temperature (21�C), at 37�C, at 50�C and at 60�C. Vickers microhardness test was performed on top and bottom surfaces using digital microhardness tester (Micro-Vickers Hardness System CV- 400DMTM, CV Instruments Namicon). The top and bottom surfaces VHN was calculated as a mean value of five determinations. Also, the microhardness ratio was calculated by dividing the top mean VHN value by bottom mean VHN value. Increased mean hardness values were recorded after heating, irrespective of resin-based tested materials. The highest hardness values were recorded after heating all three materials at 60�C, followed by the hardness recorded at 50�C, 37�C and 21�C. For top surfaces, the lowest hardness value was recorded in Dyract eXtra group when samples were warmed at room temperature and the highest hardness value was obtained in Beautifil II group when samples where heated at 60�C. For the bottom surfaces, Dyract eXtra specimens heated at 21�C presented the lowest hardness values and Beautifil II samples heated at 60�C presented the highest hardness values. On top and on bottom surfaces Dyract eXtra showed the lowest hardness values, followed by G-aenial Posterior and Beautifil II, irrespective the heating temperature.

scholarly journals Temperature Effect on the Physical Properties of Enamel Paint Layer on Cement Plaster

2021 ◽  
Vol 12 (2) ◽  
pp. 103-108
Author(s):  
Samiul Kaiser ◽  
Mohammad Salim Kaiser
Keyword(s):  
Thermal Degradation ◽  
Heating Temperature ◽  
Paint Layer ◽  
B Value ◽  
Electric Resistance Furnace ◽  
A Value ◽  
Optical Images ◽  
Different Temperatures ◽  
L Value ◽  
The Stability

The heating effect on the stability and visual colour of enamel paint on cement plaster is evaluated through light intensity ratio of three primary colours (RGB). The painted cement plaster is isochronally heated in an electric resistance furnace at different temperatures for one hour. The investigation of optical images reveals that the original colour of the paint layer on the plaster samples remains more or less unchanged up to heating at 100°C. However, thermal degradation of the samples becomes evident in colour when they are heated beyond 200°C and at 350°C the colour becomes already burned. The microstructural images of the samples at room temperature show fine and uniform grains. But at higher heating condition the microstructure of the colour sample is characterized by coarsening grain. The colour of the heated samples are then studied through tristimulus colour ‘L*’, ‘a*’ ‘b*’ and ‘E*’ values which were analyzed and evaluated in MATLAB software. The results show that after 200°C the hunter ‘L*’ value starts to decrease greatly up to 250°C. The hunter ‘a*’ value shows an increasing trend up to 100°C and then begins to decrease until 200°C. After 200°C the same increasing character is showed till 300°C. The change of hunter ‘b*’ value remains insignificant up to 100°C and shows decreasing trend between 100°C-250°C range and an increase after 250°C up to 300°C. It is graphically shown that the proportion of all three colours decreases with the increasing temparature. The overall change of colour ‘E*’ occurs with increasing heating temperature due to moisture releasing, chemical changes and thermal degradation simulteneously. The thickness of enamel paint layer comply the above degradation by showing the nature of decresing trend. Journal of Engineering Science 12(2), 2021, 103-108

Streptokinase Stability Pattern during Storage in Various Solvents and at Different Temperatures

1975 ◽  
Vol 33 (03) ◽  
pp. 586-596 ◽  
Author(s):  
M Martin ◽  
Fräulein H Auel ◽  
Keyword(s):  
Room Temperature ◽  
Group Iii ◽  
Charged Colloids ◽  
Group I ◽  
Different Temperatures ◽  
Order Of Magnitude ◽  
Stability Pattern ◽  
The Stability ◽  
Incubation Temperatures ◽  
Dextran Solution

SummaryThe activity drop of 5 u streptokinase was measured in 1 ml each of various solutions (0.9% NaCl solution, 5% glucose solution, 5% levulose solution, 10% dextran solution, gelatin solution, 3% albumin solution, Michaelis buffer, glucose (5%)-heparin (750 u/ml) solution) at different incubation temperatures (–20° c, 4° c, 20 c, 37 C), and over different observation periods (15 min, 30 min, 45 min, 60 min, 6 h, 12 h, 24 h, and 48 h). Solution media tested for streptokinase-protecting quality were broken down into three groups.Group I: Solvents displaying excellent stabilizing properties (gelatin and albumin solutions).Group II: Solvents displaying medium stabilizing properties (dextran and levulose solutions).Group III: Solvents displaying poor stabilizing properties (NaCl and glucose solutions, Michaelis buffer).In testing streptokinase concentrations as used for therapeutic purposes (1500 u/ml, 50,000 u/ml), no decay was found to take place over observation periods of up to 48 h, and no influence by different solvents (Group I, II or III) was traceable. Heparin stored with streptokinase at room temperature over a period of 48 h did not alter the streptokinase stability.Some mechanisms concerning the stability pattern of streptokinase are discussed. It appears that low streptokinase concentrations need negatively charged colloids to keep the protein structure intact. The streptokinase-protecting macro-molecules tested so far were albumin, gelatin, and streptokinase. Obviously, streptokinase by itself was able to preserve its own stability provided its concentration was of a certain order of magnitude (1500 u/ml, 50,000 u/ml).

Analysis of Volatile Organic Compounds in Disposable Food Packages at Three types of Temperature

2012 ◽  
Vol 476-478 ◽  
pp. 2625-2629
Author(s):  
Li Xie ◽  
Jiang Yu ◽  
Shuang Li ◽  
Sha Sha Diao
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Room Temperature ◽  
Heating Temperature ◽  
Food Packages ◽  
External Standard Method ◽  
Volatile Organic ◽  
Different Temperatures ◽  
Black Plastic ◽  
Method Show

Eight volatile organic compounds (VOCs) in the four disposable food packages at refrigeration temperature, room temperature and heating temperature have been analyzed by a headspace gas chromatography and mass spectrometry method. The results of external standard method show that the amount of VOCs in the four disposable packages at different temperatures are arranged in the following order: black plastic lunch box, white plastic lunch box, paper cup, paper bowl. Under the three types of temperature for an hour, the amount of VOCs in the black plastic lunch box at heating temperatures is higher (1.2382 mg/m2at 90 °C), room temperature has smaller content (0.6682 mg/m2and 0.9105 mg/m2at 20 °C and 30 °C, repectively). Content of VOCs in the white plastic lunch box increases gradually with temperature rising.

The Stability Study of Thermodynamic Parameters of Sorption of Light Hydrocarbons on Poly [Trimethylsilyl (Propyn-1)] at Different Temperatures

2019 ◽  
Vol 57 (9) ◽  
pp. 778-783
Author(s):  
V E Shiryaeva ◽  
A A Korolev ◽  
T P Popova ◽  
A Y Kanateva ◽  
A A Kurganov
Keyword(s):  
Stationary Phase ◽  
Thermodynamic Parameters ◽  
Heating Temperature ◽  
Chromatographic Determination ◽  
Stability Study ◽  
Light Hydrocarbons ◽  
Different Temperatures ◽  
Entropy Factor ◽  
The Stability

Abstract Chromatographic determination of the thermodynamic parameters of sorption for light hydrocarbons retention on a stationary phase based on poly [trimethylsilyl (propyn-1)] (PTMSP) was performed and the effect of column preheating at temperatures up to 260°C on the retention of analytes was investigated. It was shown that heating the column to 130°C does not affect the retention of the analytes. At temperatures above 130°C, the gradual decrease of the retention of analytes on PTMSP stationary phase is observed. The process is non-selective and proceeds at the same extent for all the studied hydrocarbons, regardless of the size and geometry of the molecule. Values of enthalpy and entropy of sorption of light hydrocarbons are determined for the original column and after its aging at 200°C. The enthalpy of sorption of the analytes at the PTMSP phase is practically independent on the heating temperature of the PTMSP phase, whereas the loss of entropy increases after heating. The increase of the entropy factor after the heating of the PTMSP stationary phase is associated with its aging and is confirmed by the construction of compensation functions for treated and untreated columns.

scholarly journals PHYSICAL STABILITY AND ANTIOXIDANT ACTIVITY ASSAY OF A NANOEMULSION GEL FORMULATION CONTAINING TOCOTRIENOL

2017 ◽  
Vol 9 ◽  
pp. 140
Author(s):  
Mentari Mayang Suminar ◽  
Mahdi Jufri
Keyword(s):  
Antioxidant Activity ◽  
Room Temperature ◽  
Inhibitory Concentration ◽  
Physical Stability ◽  
Tween 80 ◽  
Skin Damage ◽  
Activity Assay ◽  
Nanoemulsion Gel ◽  
Different Temperatures ◽  
The Stability

Objective: Tocotrienols have an antioxidant potential higher than that of tocopherols. Nanoemulsion gel can deliver tocotrienols into the skin toprevent skin damage caused by free radicals and improve the stability of the dosage form. The present study aimed to determine the physical stabilityand antioxidant activity of a nanoemulsion gel formulation containing tocotrienol.Methods: The tocotrienol nanoemulsion was made using tocotrienols, oleic acid, Tween 80, 96% ethanol, and propylene glycol. The gel base was madeusing a carbomer and triethanolamine. A physical stability test was conducted at three different temperatures, namely, low temperature (4±2°C),room temperature (27±2°C), and high temperature (40±2°C). The antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl methodfor determining inhibitory concentration (IC50) values.Results: Formula 1 demonstrated the best physical stability, with a pH of 6.2. The droplet size of the tocotrienol nanoemulsion gel was 596 nm, witha zeta potential value of −27.1 nm. The IC50 of the tocotrienol nanoemulsion gel was 6252.14 ppm.Conclusion: The nanoemulsion gel formulation retained antioxidant activity and was physically stable for 8 weeks.

Stability Study of Epirubicin in Nacl 0.9% Injection

1997 ◽  
Vol 31 (9) ◽  
pp. 992-995 ◽  
Author(s):  
Montserrat Pujol ◽  
Montserrat Muñoz ◽  
Josefina Prat ◽  
Victoria Girona ◽  
Jordi De Bolós
Keyword(s):  
Shelf Life ◽  
Room Temperature ◽  
Degradation Kinetics ◽  
Storage Conditions ◽  
Hplc Method ◽  
Stability Study ◽  
Chemistry Laboratory ◽  
Maximum Decrease ◽  
Different Temperatures ◽  
The Stability

Objective To determine the stability of epirubicin in NaCl 0.9% injection under hospital storage conditions. Methods NaCl 0.9% solution was added to epirubicin iyophilized powder to make a final concentration of 1 mg/mL to study the degradation kinetics and 2 mg/mL to study the stability in polypropylene syringes under hospital conditions. Setting Physical chemistry laboratory, Unitat de Fisicoquímica, Universitat de Barcelona. Main outcome Measures Solutions of epirubicin at 2 mg/mL in NaCl 0.9% solutions stored in plastic syringes were studied under hospital conditions at room temperature (25 ± 1 °C) and under refrigeration (4 ± 1 °C) both protected from light and exposed to room light (~50 lumens/m2). All samples were studied in triplicate and epirubicin concentrations were obtained periodically throughout each storage/time condition via a specific stability-indicating HPLC method. To determine the degradation kinetics, solutions of epirubicin in NaCl 0.9% at 1 mg/mL were stored at different temperatures (40, 50, and 60 °C) to obtain the rate degradation constant and the shelf life at room temperature and under refrigeration. Results The degradation of epirubicin in NaCl 0.9% solutions follows first-order kinetics. The shelf life was defined as the time by which the epirubicin concentration had decreased by 10% from the initial concentration. In this study, epirubicin was stable in NaCl 0.9% injection stored in polypropylene containers for all time periods and all conditions. That results in a shelf life of at least 14 and 180 days at 25 and 4 °C, respectively. The maximum decrease in epirubicin concentration observed at 25 °C and 14 days was 4%, and at 4 °C and 180 days was 8%. The predicted shelf life obtained from the Arrhenius equation was 72.9 ± 0.2 and 3070 ± 15 days at 25 and 4 °C, respectively, in both dark and illuminated conditions. Conclusions Solutions of epirubicin in NaCl 0.9% at 2 mg/mL are chemically stable when they are stored in polypropylene syringes under hospital storage conditions. No special precaution is neccessary to protect epirubicin solutions (2 mg/mL) from light.

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