The effect of temperature on the stability of compounds used as UV-MALDI-MS matrix: 2,5-dihydroxybenzoic acid, 2,4,6-trihydroxyacetophenone, α-cyano-4-hydroxycinnamic acid, 3,5-dimethoxy-4-hydroxycinnamic acid, nor-harmane and harmane

2009 ◽  
Vol 44 (2) ◽  
pp. 260-277 ◽  
Author(s):  
Olga I. Tarzi ◽  
Hiroshi Nonami ◽  
Rosa Erra-Balsells
Keyword(s):  
Hydroxycinnamic Acid ◽  
Maldi Ms ◽  
Effect Of Temperature ◽  
Dihydroxybenzoic Acid ◽  
The Stability

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

The effect of temperature and time on the properties of 2D Cs2ZnBr4 perovskite nanocrystals and its application in a Schottky barrier device

2021 ◽  
Author(s):  
Olusola Akinbami ◽  
Grace N Ngubeni ◽  
Francis Otieno ◽  
Rudo Kadzutu-Sithole ◽  
Cebisa Linganiso ◽  
...  
Keyword(s):  
Solar Cell ◽  
Schottky Barrier ◽  
Effect Of Temperature ◽  
Inorganic Perovskite ◽  
Perovskite Nanocrystals ◽  
The Stability ◽  
Barrier Device

2D hybrid perovskites are promising materials for solar cell applications, in particular, cesium based perovskite nanocrystals as they offer the stability that is absent in organic-inorganic perovskite. However, the most...

Temperature Dependence of Degradation of Colored Oxo-Biodegradable Low-Density Polyethylene Films under Accelerated Thermal Aging

2017 ◽  
Vol 890 ◽  
pp. 82-85 ◽  
Author(s):  
Reymark D. Maalihan ◽  
Bryan B. Pajarito
Keyword(s):  
Thermal Aging ◽  
Degradation Products ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Polyethylene Films ◽  
Hot Air ◽  
Taguchi Design Of Experiments ◽  
Oxidant Concentration ◽  
The Stability

This work reports the effect of temperature on degradation of colored low-density polyethylene (PE) films during thermal aging. Film samples were formulated according to Taguchi design of experiments where colorant, thickness, and pro-oxidant concentration were varied accordingly. Tensile properties of films were monitored with time during heat aging in a hot air oven at 50, 70, and 90 °C. Likewise, surfaces of aged films were analyzed to evaluate the degree of oxidation of PE during thermal aging. The Arrhenius equation was then used to predict the lifetime of PE at an in-use temperature of 30 °C. Results indicate that increasing the temperature reduces the tensile strength and modulus of films. Formation of carbonyl groups as degradation products is also observed at higher temperatures. Consequently, thermal aging at 90 °C offers the highest extent of degradation of exposed films. Regression analysis reveals that white films degrade at a higher rate than yellow and non-colored films. The presence of TiO2 in white films shortens the lifetime of PE while amine stabilizer in yellow films enhances the stability of PE during thermal aging.

scholarly journals Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Andery Lim ◽  
Noramaliyana Haji Manaf ◽  
Kushan Tennakoon ◽  
R. L. N. Chandrakanthi ◽  
Linda Biaw Leng Lim ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Structural Changes ◽  
Dye Sensitized Solar Cells ◽  
Life Time ◽  
Effect Of Temperature ◽  
Synergistic Activity ◽  
Electron Recombination ◽  
Positive Interaction ◽  
Effective Electron ◽  
The Stability

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect.

scholarly journals Effect of temperature and relative humidity on the stability of infectious porcine reproductive and respiratory syndrome virus in aerosols

2007 ◽  
Vol 38 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Joseph Hermann ◽  
Steve Hoff ◽  
Claudia Muñoz-Zanzi ◽  
Kyoung-Jin Yoon ◽  
Michael Roof ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Effect Of Temperature ◽  
Respiratory Syndrome Virus ◽  
The Stability

scholarly journals SYNTHESIS OF NEW SUBSTITUTED PROCAINE HYDROCHLORIDE COMPOUNDS AND THEIR USE IN SPECTROPHOTOMETRIC DETERMINATION OF TETRACYCLINE HYDROCHLORIDE THROUGH DIAZOTIZATION-COUPLING REACTIONS

2021 ◽  
Vol 18 (39) ◽  
pp. 14-32
Author(s):  
Hind Sadiq Al-WARD ◽  
Mouayed Qassssim AL-ABACHI ◽  
Mohammed Rifaat AHMED
Keyword(s):  
Stability Constant ◽  
Thermodynamic Parameters ◽  
Coupling Reaction ◽  
Water Soluble ◽  
Procaine Hydrochloride ◽  
Effect Of Temperature ◽  
Basic Medium ◽  
Fast Method ◽  
The Stability

Background: Tetracycline is one of the most important antibiotics. It is used to treat many different bacterial infections. It is often used in treating severe acne, or sexually transmitted diseases such as syphilis, gonorrhea, or chlamydia. In some cases, tetracycline is used when penicillin or another antibiotic cannot be used to treat serious infections such as the ones caused by Bacillus anthracis, Listeria, Clostridium, Actinomyces. Aim: synthesized a new novel reagent used to determine TCH spectrophotometrically by using diazonium and coupling reaction. Methods: Four new substituted procaine derivatives were prepared by simple organic methods using aniline derivatives. A spectrophotometric approach was established for the micro-determination of TCH. The stoichiometry was investigated using mole ratio and continuous variation methods, and the stability constant was also estimated. The ΔG, ΔH, and ΔS were determined as thermodynamic parameters for evaluating the effect of temperature on the reaction. Results: Substituted procaine derivatives were prepared, and o-hydroxy procaine seems to be the best reagent used to determine TCH by diazotization and coupling reaction. The result was a yellow water-soluble dye with a maximum absorbance of 380 nm. The reaction conditions were studied and optimized. Beers law was obeyed over a concentration range (2.5–50) μg.mL-1 for TCH. The molar absorptivity was (14.4669.103) L.mol-1.cm-1, and the detection limit was (0.5052) μg.mL-1. The stoichiometry of the formed product was found 1:1 (o-hydroxyprocaine: TCH). The stability constant indicated that the product formed was stable, and the thermodynamic parameters showed that the diazonium salt reaction was preferred to occur at a low temperature. Conclusions: a simple, accurate, and fast method was developed to determine TCH in pure form and pharmaceuticals by coupling the TCH with a newly synthesized procaine derivative reagent (o-hydroxy procaine) in a basic medium.

Effect of temperature and PH value on the stability of bioactive compounds and antioxidative activity of juice from colour‐fleshed potatoes

2019 ◽  
Vol 55 (6) ◽  
pp. 2335-2343
Author(s):  
Elżbieta Rytel ◽  
Agnieszka Tajner‐Czopek ◽  
Agnieszka Kita ◽  
Anna Sokół‐Łętowska ◽  
Alicja Z. Kucharska ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Antioxidative Activity ◽  
Ph Value ◽  
Effect Of Temperature ◽  
The Stability

Effect of temperature regimes on the stability of the process of drawing optical fibers

1986 ◽  
Vol 27 (3) ◽  
pp. 417-423
Author(s):  
V. L. Kolpashchikov ◽  
Yu. I. Lanin ◽  
O. G. Martynenko ◽  
A. I. Shnip
Keyword(s):  
Optical Fibers ◽  
Effect Of Temperature ◽  
Temperature Regimes ◽  
The Stability
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